xref: /openbmc/linux/kernel/events/core.c (revision 62a9bbf2)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Performance events core code:
4  *
5  *  Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
6  *  Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
7  *  Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
8  *  Copyright  ©  2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9  */
10 
11 #include <linux/fs.h>
12 #include <linux/mm.h>
13 #include <linux/cpu.h>
14 #include <linux/smp.h>
15 #include <linux/idr.h>
16 #include <linux/file.h>
17 #include <linux/poll.h>
18 #include <linux/slab.h>
19 #include <linux/hash.h>
20 #include <linux/tick.h>
21 #include <linux/sysfs.h>
22 #include <linux/dcache.h>
23 #include <linux/percpu.h>
24 #include <linux/ptrace.h>
25 #include <linux/reboot.h>
26 #include <linux/vmstat.h>
27 #include <linux/device.h>
28 #include <linux/export.h>
29 #include <linux/vmalloc.h>
30 #include <linux/hardirq.h>
31 #include <linux/hugetlb.h>
32 #include <linux/rculist.h>
33 #include <linux/uaccess.h>
34 #include <linux/syscalls.h>
35 #include <linux/anon_inodes.h>
36 #include <linux/kernel_stat.h>
37 #include <linux/cgroup.h>
38 #include <linux/perf_event.h>
39 #include <linux/trace_events.h>
40 #include <linux/hw_breakpoint.h>
41 #include <linux/mm_types.h>
42 #include <linux/module.h>
43 #include <linux/mman.h>
44 #include <linux/compat.h>
45 #include <linux/bpf.h>
46 #include <linux/filter.h>
47 #include <linux/namei.h>
48 #include <linux/parser.h>
49 #include <linux/sched/clock.h>
50 #include <linux/sched/mm.h>
51 #include <linux/proc_ns.h>
52 #include <linux/mount.h>
53 #include <linux/min_heap.h>
54 #include <linux/highmem.h>
55 #include <linux/pgtable.h>
56 #include <linux/buildid.h>
57 #include <linux/task_work.h>
58 
59 #include "internal.h"
60 
61 #include <asm/irq_regs.h>
62 
63 typedef int (*remote_function_f)(void *);
64 
65 struct remote_function_call {
66 	struct task_struct	*p;
67 	remote_function_f	func;
68 	void			*info;
69 	int			ret;
70 };
71 
72 static void remote_function(void *data)
73 {
74 	struct remote_function_call *tfc = data;
75 	struct task_struct *p = tfc->p;
76 
77 	if (p) {
78 		/* -EAGAIN */
79 		if (task_cpu(p) != smp_processor_id())
80 			return;
81 
82 		/*
83 		 * Now that we're on right CPU with IRQs disabled, we can test
84 		 * if we hit the right task without races.
85 		 */
86 
87 		tfc->ret = -ESRCH; /* No such (running) process */
88 		if (p != current)
89 			return;
90 	}
91 
92 	tfc->ret = tfc->func(tfc->info);
93 }
94 
95 /**
96  * task_function_call - call a function on the cpu on which a task runs
97  * @p:		the task to evaluate
98  * @func:	the function to be called
99  * @info:	the function call argument
100  *
101  * Calls the function @func when the task is currently running. This might
102  * be on the current CPU, which just calls the function directly.  This will
103  * retry due to any failures in smp_call_function_single(), such as if the
104  * task_cpu() goes offline concurrently.
105  *
106  * returns @func return value or -ESRCH or -ENXIO when the process isn't running
107  */
108 static int
109 task_function_call(struct task_struct *p, remote_function_f func, void *info)
110 {
111 	struct remote_function_call data = {
112 		.p	= p,
113 		.func	= func,
114 		.info	= info,
115 		.ret	= -EAGAIN,
116 	};
117 	int ret;
118 
119 	for (;;) {
120 		ret = smp_call_function_single(task_cpu(p), remote_function,
121 					       &data, 1);
122 		if (!ret)
123 			ret = data.ret;
124 
125 		if (ret != -EAGAIN)
126 			break;
127 
128 		cond_resched();
129 	}
130 
131 	return ret;
132 }
133 
134 /**
135  * cpu_function_call - call a function on the cpu
136  * @cpu:	target cpu to queue this function
137  * @func:	the function to be called
138  * @info:	the function call argument
139  *
140  * Calls the function @func on the remote cpu.
141  *
142  * returns: @func return value or -ENXIO when the cpu is offline
143  */
144 static int cpu_function_call(int cpu, remote_function_f func, void *info)
145 {
146 	struct remote_function_call data = {
147 		.p	= NULL,
148 		.func	= func,
149 		.info	= info,
150 		.ret	= -ENXIO, /* No such CPU */
151 	};
152 
153 	smp_call_function_single(cpu, remote_function, &data, 1);
154 
155 	return data.ret;
156 }
157 
158 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
159 			  struct perf_event_context *ctx)
160 {
161 	raw_spin_lock(&cpuctx->ctx.lock);
162 	if (ctx)
163 		raw_spin_lock(&ctx->lock);
164 }
165 
166 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
167 			    struct perf_event_context *ctx)
168 {
169 	if (ctx)
170 		raw_spin_unlock(&ctx->lock);
171 	raw_spin_unlock(&cpuctx->ctx.lock);
172 }
173 
174 #define TASK_TOMBSTONE ((void *)-1L)
175 
176 static bool is_kernel_event(struct perf_event *event)
177 {
178 	return READ_ONCE(event->owner) == TASK_TOMBSTONE;
179 }
180 
181 static DEFINE_PER_CPU(struct perf_cpu_context, perf_cpu_context);
182 
183 struct perf_event_context *perf_cpu_task_ctx(void)
184 {
185 	lockdep_assert_irqs_disabled();
186 	return this_cpu_ptr(&perf_cpu_context)->task_ctx;
187 }
188 
189 /*
190  * On task ctx scheduling...
191  *
192  * When !ctx->nr_events a task context will not be scheduled. This means
193  * we can disable the scheduler hooks (for performance) without leaving
194  * pending task ctx state.
195  *
196  * This however results in two special cases:
197  *
198  *  - removing the last event from a task ctx; this is relatively straight
199  *    forward and is done in __perf_remove_from_context.
200  *
201  *  - adding the first event to a task ctx; this is tricky because we cannot
202  *    rely on ctx->is_active and therefore cannot use event_function_call().
203  *    See perf_install_in_context().
204  *
205  * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
206  */
207 
208 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
209 			struct perf_event_context *, void *);
210 
211 struct event_function_struct {
212 	struct perf_event *event;
213 	event_f func;
214 	void *data;
215 };
216 
217 static int event_function(void *info)
218 {
219 	struct event_function_struct *efs = info;
220 	struct perf_event *event = efs->event;
221 	struct perf_event_context *ctx = event->ctx;
222 	struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
223 	struct perf_event_context *task_ctx = cpuctx->task_ctx;
224 	int ret = 0;
225 
226 	lockdep_assert_irqs_disabled();
227 
228 	perf_ctx_lock(cpuctx, task_ctx);
229 	/*
230 	 * Since we do the IPI call without holding ctx->lock things can have
231 	 * changed, double check we hit the task we set out to hit.
232 	 */
233 	if (ctx->task) {
234 		if (ctx->task != current) {
235 			ret = -ESRCH;
236 			goto unlock;
237 		}
238 
239 		/*
240 		 * We only use event_function_call() on established contexts,
241 		 * and event_function() is only ever called when active (or
242 		 * rather, we'll have bailed in task_function_call() or the
243 		 * above ctx->task != current test), therefore we must have
244 		 * ctx->is_active here.
245 		 */
246 		WARN_ON_ONCE(!ctx->is_active);
247 		/*
248 		 * And since we have ctx->is_active, cpuctx->task_ctx must
249 		 * match.
250 		 */
251 		WARN_ON_ONCE(task_ctx != ctx);
252 	} else {
253 		WARN_ON_ONCE(&cpuctx->ctx != ctx);
254 	}
255 
256 	efs->func(event, cpuctx, ctx, efs->data);
257 unlock:
258 	perf_ctx_unlock(cpuctx, task_ctx);
259 
260 	return ret;
261 }
262 
263 static void event_function_call(struct perf_event *event, event_f func, void *data)
264 {
265 	struct perf_event_context *ctx = event->ctx;
266 	struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
267 	struct event_function_struct efs = {
268 		.event = event,
269 		.func = func,
270 		.data = data,
271 	};
272 
273 	if (!event->parent) {
274 		/*
275 		 * If this is a !child event, we must hold ctx::mutex to
276 		 * stabilize the event->ctx relation. See
277 		 * perf_event_ctx_lock().
278 		 */
279 		lockdep_assert_held(&ctx->mutex);
280 	}
281 
282 	if (!task) {
283 		cpu_function_call(event->cpu, event_function, &efs);
284 		return;
285 	}
286 
287 	if (task == TASK_TOMBSTONE)
288 		return;
289 
290 again:
291 	if (!task_function_call(task, event_function, &efs))
292 		return;
293 
294 	raw_spin_lock_irq(&ctx->lock);
295 	/*
296 	 * Reload the task pointer, it might have been changed by
297 	 * a concurrent perf_event_context_sched_out().
298 	 */
299 	task = ctx->task;
300 	if (task == TASK_TOMBSTONE) {
301 		raw_spin_unlock_irq(&ctx->lock);
302 		return;
303 	}
304 	if (ctx->is_active) {
305 		raw_spin_unlock_irq(&ctx->lock);
306 		goto again;
307 	}
308 	func(event, NULL, ctx, data);
309 	raw_spin_unlock_irq(&ctx->lock);
310 }
311 
312 /*
313  * Similar to event_function_call() + event_function(), but hard assumes IRQs
314  * are already disabled and we're on the right CPU.
315  */
316 static void event_function_local(struct perf_event *event, event_f func, void *data)
317 {
318 	struct perf_event_context *ctx = event->ctx;
319 	struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
320 	struct task_struct *task = READ_ONCE(ctx->task);
321 	struct perf_event_context *task_ctx = NULL;
322 
323 	lockdep_assert_irqs_disabled();
324 
325 	if (task) {
326 		if (task == TASK_TOMBSTONE)
327 			return;
328 
329 		task_ctx = ctx;
330 	}
331 
332 	perf_ctx_lock(cpuctx, task_ctx);
333 
334 	task = ctx->task;
335 	if (task == TASK_TOMBSTONE)
336 		goto unlock;
337 
338 	if (task) {
339 		/*
340 		 * We must be either inactive or active and the right task,
341 		 * otherwise we're screwed, since we cannot IPI to somewhere
342 		 * else.
343 		 */
344 		if (ctx->is_active) {
345 			if (WARN_ON_ONCE(task != current))
346 				goto unlock;
347 
348 			if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
349 				goto unlock;
350 		}
351 	} else {
352 		WARN_ON_ONCE(&cpuctx->ctx != ctx);
353 	}
354 
355 	func(event, cpuctx, ctx, data);
356 unlock:
357 	perf_ctx_unlock(cpuctx, task_ctx);
358 }
359 
360 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
361 		       PERF_FLAG_FD_OUTPUT  |\
362 		       PERF_FLAG_PID_CGROUP |\
363 		       PERF_FLAG_FD_CLOEXEC)
364 
365 /*
366  * branch priv levels that need permission checks
367  */
368 #define PERF_SAMPLE_BRANCH_PERM_PLM \
369 	(PERF_SAMPLE_BRANCH_KERNEL |\
370 	 PERF_SAMPLE_BRANCH_HV)
371 
372 enum event_type_t {
373 	EVENT_FLEXIBLE = 0x1,
374 	EVENT_PINNED = 0x2,
375 	EVENT_TIME = 0x4,
376 	/* see ctx_resched() for details */
377 	EVENT_CPU = 0x8,
378 	EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
379 };
380 
381 /*
382  * perf_sched_events : >0 events exist
383  */
384 
385 static void perf_sched_delayed(struct work_struct *work);
386 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
387 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
388 static DEFINE_MUTEX(perf_sched_mutex);
389 static atomic_t perf_sched_count;
390 
391 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
392 
393 static atomic_t nr_mmap_events __read_mostly;
394 static atomic_t nr_comm_events __read_mostly;
395 static atomic_t nr_namespaces_events __read_mostly;
396 static atomic_t nr_task_events __read_mostly;
397 static atomic_t nr_freq_events __read_mostly;
398 static atomic_t nr_switch_events __read_mostly;
399 static atomic_t nr_ksymbol_events __read_mostly;
400 static atomic_t nr_bpf_events __read_mostly;
401 static atomic_t nr_cgroup_events __read_mostly;
402 static atomic_t nr_text_poke_events __read_mostly;
403 static atomic_t nr_build_id_events __read_mostly;
404 
405 static LIST_HEAD(pmus);
406 static DEFINE_MUTEX(pmus_lock);
407 static struct srcu_struct pmus_srcu;
408 static cpumask_var_t perf_online_mask;
409 static struct kmem_cache *perf_event_cache;
410 
411 /*
412  * perf event paranoia level:
413  *  -1 - not paranoid at all
414  *   0 - disallow raw tracepoint access for unpriv
415  *   1 - disallow cpu events for unpriv
416  *   2 - disallow kernel profiling for unpriv
417  */
418 int sysctl_perf_event_paranoid __read_mostly = 2;
419 
420 /* Minimum for 512 kiB + 1 user control page */
421 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
422 
423 /*
424  * max perf event sample rate
425  */
426 #define DEFAULT_MAX_SAMPLE_RATE		100000
427 #define DEFAULT_SAMPLE_PERIOD_NS	(NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
428 #define DEFAULT_CPU_TIME_MAX_PERCENT	25
429 
430 int sysctl_perf_event_sample_rate __read_mostly	= DEFAULT_MAX_SAMPLE_RATE;
431 
432 static int max_samples_per_tick __read_mostly	= DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
433 static int perf_sample_period_ns __read_mostly	= DEFAULT_SAMPLE_PERIOD_NS;
434 
435 static int perf_sample_allowed_ns __read_mostly =
436 	DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
437 
438 static void update_perf_cpu_limits(void)
439 {
440 	u64 tmp = perf_sample_period_ns;
441 
442 	tmp *= sysctl_perf_cpu_time_max_percent;
443 	tmp = div_u64(tmp, 100);
444 	if (!tmp)
445 		tmp = 1;
446 
447 	WRITE_ONCE(perf_sample_allowed_ns, tmp);
448 }
449 
450 static bool perf_rotate_context(struct perf_cpu_pmu_context *cpc);
451 
452 int perf_proc_update_handler(struct ctl_table *table, int write,
453 		void *buffer, size_t *lenp, loff_t *ppos)
454 {
455 	int ret;
456 	int perf_cpu = sysctl_perf_cpu_time_max_percent;
457 	/*
458 	 * If throttling is disabled don't allow the write:
459 	 */
460 	if (write && (perf_cpu == 100 || perf_cpu == 0))
461 		return -EINVAL;
462 
463 	ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
464 	if (ret || !write)
465 		return ret;
466 
467 	max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
468 	perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
469 	update_perf_cpu_limits();
470 
471 	return 0;
472 }
473 
474 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
475 
476 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
477 		void *buffer, size_t *lenp, loff_t *ppos)
478 {
479 	int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
480 
481 	if (ret || !write)
482 		return ret;
483 
484 	if (sysctl_perf_cpu_time_max_percent == 100 ||
485 	    sysctl_perf_cpu_time_max_percent == 0) {
486 		printk(KERN_WARNING
487 		       "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
488 		WRITE_ONCE(perf_sample_allowed_ns, 0);
489 	} else {
490 		update_perf_cpu_limits();
491 	}
492 
493 	return 0;
494 }
495 
496 /*
497  * perf samples are done in some very critical code paths (NMIs).
498  * If they take too much CPU time, the system can lock up and not
499  * get any real work done.  This will drop the sample rate when
500  * we detect that events are taking too long.
501  */
502 #define NR_ACCUMULATED_SAMPLES 128
503 static DEFINE_PER_CPU(u64, running_sample_length);
504 
505 static u64 __report_avg;
506 static u64 __report_allowed;
507 
508 static void perf_duration_warn(struct irq_work *w)
509 {
510 	printk_ratelimited(KERN_INFO
511 		"perf: interrupt took too long (%lld > %lld), lowering "
512 		"kernel.perf_event_max_sample_rate to %d\n",
513 		__report_avg, __report_allowed,
514 		sysctl_perf_event_sample_rate);
515 }
516 
517 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
518 
519 void perf_sample_event_took(u64 sample_len_ns)
520 {
521 	u64 max_len = READ_ONCE(perf_sample_allowed_ns);
522 	u64 running_len;
523 	u64 avg_len;
524 	u32 max;
525 
526 	if (max_len == 0)
527 		return;
528 
529 	/* Decay the counter by 1 average sample. */
530 	running_len = __this_cpu_read(running_sample_length);
531 	running_len -= running_len/NR_ACCUMULATED_SAMPLES;
532 	running_len += sample_len_ns;
533 	__this_cpu_write(running_sample_length, running_len);
534 
535 	/*
536 	 * Note: this will be biased artifically low until we have
537 	 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
538 	 * from having to maintain a count.
539 	 */
540 	avg_len = running_len/NR_ACCUMULATED_SAMPLES;
541 	if (avg_len <= max_len)
542 		return;
543 
544 	__report_avg = avg_len;
545 	__report_allowed = max_len;
546 
547 	/*
548 	 * Compute a throttle threshold 25% below the current duration.
549 	 */
550 	avg_len += avg_len / 4;
551 	max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
552 	if (avg_len < max)
553 		max /= (u32)avg_len;
554 	else
555 		max = 1;
556 
557 	WRITE_ONCE(perf_sample_allowed_ns, avg_len);
558 	WRITE_ONCE(max_samples_per_tick, max);
559 
560 	sysctl_perf_event_sample_rate = max * HZ;
561 	perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
562 
563 	if (!irq_work_queue(&perf_duration_work)) {
564 		early_printk("perf: interrupt took too long (%lld > %lld), lowering "
565 			     "kernel.perf_event_max_sample_rate to %d\n",
566 			     __report_avg, __report_allowed,
567 			     sysctl_perf_event_sample_rate);
568 	}
569 }
570 
571 static atomic64_t perf_event_id;
572 
573 static void update_context_time(struct perf_event_context *ctx);
574 static u64 perf_event_time(struct perf_event *event);
575 
576 void __weak perf_event_print_debug(void)	{ }
577 
578 static inline u64 perf_clock(void)
579 {
580 	return local_clock();
581 }
582 
583 static inline u64 perf_event_clock(struct perf_event *event)
584 {
585 	return event->clock();
586 }
587 
588 /*
589  * State based event timekeeping...
590  *
591  * The basic idea is to use event->state to determine which (if any) time
592  * fields to increment with the current delta. This means we only need to
593  * update timestamps when we change state or when they are explicitly requested
594  * (read).
595  *
596  * Event groups make things a little more complicated, but not terribly so. The
597  * rules for a group are that if the group leader is OFF the entire group is
598  * OFF, irrespecive of what the group member states are. This results in
599  * __perf_effective_state().
600  *
601  * A futher ramification is that when a group leader flips between OFF and
602  * !OFF, we need to update all group member times.
603  *
604  *
605  * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
606  * need to make sure the relevant context time is updated before we try and
607  * update our timestamps.
608  */
609 
610 static __always_inline enum perf_event_state
611 __perf_effective_state(struct perf_event *event)
612 {
613 	struct perf_event *leader = event->group_leader;
614 
615 	if (leader->state <= PERF_EVENT_STATE_OFF)
616 		return leader->state;
617 
618 	return event->state;
619 }
620 
621 static __always_inline void
622 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
623 {
624 	enum perf_event_state state = __perf_effective_state(event);
625 	u64 delta = now - event->tstamp;
626 
627 	*enabled = event->total_time_enabled;
628 	if (state >= PERF_EVENT_STATE_INACTIVE)
629 		*enabled += delta;
630 
631 	*running = event->total_time_running;
632 	if (state >= PERF_EVENT_STATE_ACTIVE)
633 		*running += delta;
634 }
635 
636 static void perf_event_update_time(struct perf_event *event)
637 {
638 	u64 now = perf_event_time(event);
639 
640 	__perf_update_times(event, now, &event->total_time_enabled,
641 					&event->total_time_running);
642 	event->tstamp = now;
643 }
644 
645 static void perf_event_update_sibling_time(struct perf_event *leader)
646 {
647 	struct perf_event *sibling;
648 
649 	for_each_sibling_event(sibling, leader)
650 		perf_event_update_time(sibling);
651 }
652 
653 static void
654 perf_event_set_state(struct perf_event *event, enum perf_event_state state)
655 {
656 	if (event->state == state)
657 		return;
658 
659 	perf_event_update_time(event);
660 	/*
661 	 * If a group leader gets enabled/disabled all its siblings
662 	 * are affected too.
663 	 */
664 	if ((event->state < 0) ^ (state < 0))
665 		perf_event_update_sibling_time(event);
666 
667 	WRITE_ONCE(event->state, state);
668 }
669 
670 /*
671  * UP store-release, load-acquire
672  */
673 
674 #define __store_release(ptr, val)					\
675 do {									\
676 	barrier();							\
677 	WRITE_ONCE(*(ptr), (val));					\
678 } while (0)
679 
680 #define __load_acquire(ptr)						\
681 ({									\
682 	__unqual_scalar_typeof(*(ptr)) ___p = READ_ONCE(*(ptr));	\
683 	barrier();							\
684 	___p;								\
685 })
686 
687 static void perf_ctx_disable(struct perf_event_context *ctx)
688 {
689 	struct perf_event_pmu_context *pmu_ctx;
690 
691 	list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry)
692 		perf_pmu_disable(pmu_ctx->pmu);
693 }
694 
695 static void perf_ctx_enable(struct perf_event_context *ctx)
696 {
697 	struct perf_event_pmu_context *pmu_ctx;
698 
699 	list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry)
700 		perf_pmu_enable(pmu_ctx->pmu);
701 }
702 
703 static void ctx_sched_out(struct perf_event_context *ctx, enum event_type_t event_type);
704 static void ctx_sched_in(struct perf_event_context *ctx, enum event_type_t event_type);
705 
706 #ifdef CONFIG_CGROUP_PERF
707 
708 static inline bool
709 perf_cgroup_match(struct perf_event *event)
710 {
711 	struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
712 
713 	/* @event doesn't care about cgroup */
714 	if (!event->cgrp)
715 		return true;
716 
717 	/* wants specific cgroup scope but @cpuctx isn't associated with any */
718 	if (!cpuctx->cgrp)
719 		return false;
720 
721 	/*
722 	 * Cgroup scoping is recursive.  An event enabled for a cgroup is
723 	 * also enabled for all its descendant cgroups.  If @cpuctx's
724 	 * cgroup is a descendant of @event's (the test covers identity
725 	 * case), it's a match.
726 	 */
727 	return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
728 				    event->cgrp->css.cgroup);
729 }
730 
731 static inline void perf_detach_cgroup(struct perf_event *event)
732 {
733 	css_put(&event->cgrp->css);
734 	event->cgrp = NULL;
735 }
736 
737 static inline int is_cgroup_event(struct perf_event *event)
738 {
739 	return event->cgrp != NULL;
740 }
741 
742 static inline u64 perf_cgroup_event_time(struct perf_event *event)
743 {
744 	struct perf_cgroup_info *t;
745 
746 	t = per_cpu_ptr(event->cgrp->info, event->cpu);
747 	return t->time;
748 }
749 
750 static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now)
751 {
752 	struct perf_cgroup_info *t;
753 
754 	t = per_cpu_ptr(event->cgrp->info, event->cpu);
755 	if (!__load_acquire(&t->active))
756 		return t->time;
757 	now += READ_ONCE(t->timeoffset);
758 	return now;
759 }
760 
761 static inline void __update_cgrp_time(struct perf_cgroup_info *info, u64 now, bool adv)
762 {
763 	if (adv)
764 		info->time += now - info->timestamp;
765 	info->timestamp = now;
766 	/*
767 	 * see update_context_time()
768 	 */
769 	WRITE_ONCE(info->timeoffset, info->time - info->timestamp);
770 }
771 
772 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx, bool final)
773 {
774 	struct perf_cgroup *cgrp = cpuctx->cgrp;
775 	struct cgroup_subsys_state *css;
776 	struct perf_cgroup_info *info;
777 
778 	if (cgrp) {
779 		u64 now = perf_clock();
780 
781 		for (css = &cgrp->css; css; css = css->parent) {
782 			cgrp = container_of(css, struct perf_cgroup, css);
783 			info = this_cpu_ptr(cgrp->info);
784 
785 			__update_cgrp_time(info, now, true);
786 			if (final)
787 				__store_release(&info->active, 0);
788 		}
789 	}
790 }
791 
792 static inline void update_cgrp_time_from_event(struct perf_event *event)
793 {
794 	struct perf_cgroup_info *info;
795 
796 	/*
797 	 * ensure we access cgroup data only when needed and
798 	 * when we know the cgroup is pinned (css_get)
799 	 */
800 	if (!is_cgroup_event(event))
801 		return;
802 
803 	info = this_cpu_ptr(event->cgrp->info);
804 	/*
805 	 * Do not update time when cgroup is not active
806 	 */
807 	if (info->active)
808 		__update_cgrp_time(info, perf_clock(), true);
809 }
810 
811 static inline void
812 perf_cgroup_set_timestamp(struct perf_cpu_context *cpuctx)
813 {
814 	struct perf_event_context *ctx = &cpuctx->ctx;
815 	struct perf_cgroup *cgrp = cpuctx->cgrp;
816 	struct perf_cgroup_info *info;
817 	struct cgroup_subsys_state *css;
818 
819 	/*
820 	 * ctx->lock held by caller
821 	 * ensure we do not access cgroup data
822 	 * unless we have the cgroup pinned (css_get)
823 	 */
824 	if (!cgrp)
825 		return;
826 
827 	WARN_ON_ONCE(!ctx->nr_cgroups);
828 
829 	for (css = &cgrp->css; css; css = css->parent) {
830 		cgrp = container_of(css, struct perf_cgroup, css);
831 		info = this_cpu_ptr(cgrp->info);
832 		__update_cgrp_time(info, ctx->timestamp, false);
833 		__store_release(&info->active, 1);
834 	}
835 }
836 
837 /*
838  * reschedule events based on the cgroup constraint of task.
839  */
840 static void perf_cgroup_switch(struct task_struct *task)
841 {
842 	struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
843 	struct perf_cgroup *cgrp;
844 
845 	/*
846 	 * cpuctx->cgrp is set when the first cgroup event enabled,
847 	 * and is cleared when the last cgroup event disabled.
848 	 */
849 	if (READ_ONCE(cpuctx->cgrp) == NULL)
850 		return;
851 
852 	WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
853 
854 	cgrp = perf_cgroup_from_task(task, NULL);
855 	if (READ_ONCE(cpuctx->cgrp) == cgrp)
856 		return;
857 
858 	perf_ctx_lock(cpuctx, cpuctx->task_ctx);
859 	perf_ctx_disable(&cpuctx->ctx);
860 
861 	ctx_sched_out(&cpuctx->ctx, EVENT_ALL);
862 	/*
863 	 * must not be done before ctxswout due
864 	 * to update_cgrp_time_from_cpuctx() in
865 	 * ctx_sched_out()
866 	 */
867 	cpuctx->cgrp = cgrp;
868 	/*
869 	 * set cgrp before ctxsw in to allow
870 	 * perf_cgroup_set_timestamp() in ctx_sched_in()
871 	 * to not have to pass task around
872 	 */
873 	ctx_sched_in(&cpuctx->ctx, EVENT_ALL);
874 
875 	perf_ctx_enable(&cpuctx->ctx);
876 	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
877 }
878 
879 static int perf_cgroup_ensure_storage(struct perf_event *event,
880 				struct cgroup_subsys_state *css)
881 {
882 	struct perf_cpu_context *cpuctx;
883 	struct perf_event **storage;
884 	int cpu, heap_size, ret = 0;
885 
886 	/*
887 	 * Allow storage to have sufficent space for an iterator for each
888 	 * possibly nested cgroup plus an iterator for events with no cgroup.
889 	 */
890 	for (heap_size = 1; css; css = css->parent)
891 		heap_size++;
892 
893 	for_each_possible_cpu(cpu) {
894 		cpuctx = per_cpu_ptr(&perf_cpu_context, cpu);
895 		if (heap_size <= cpuctx->heap_size)
896 			continue;
897 
898 		storage = kmalloc_node(heap_size * sizeof(struct perf_event *),
899 				       GFP_KERNEL, cpu_to_node(cpu));
900 		if (!storage) {
901 			ret = -ENOMEM;
902 			break;
903 		}
904 
905 		raw_spin_lock_irq(&cpuctx->ctx.lock);
906 		if (cpuctx->heap_size < heap_size) {
907 			swap(cpuctx->heap, storage);
908 			if (storage == cpuctx->heap_default)
909 				storage = NULL;
910 			cpuctx->heap_size = heap_size;
911 		}
912 		raw_spin_unlock_irq(&cpuctx->ctx.lock);
913 
914 		kfree(storage);
915 	}
916 
917 	return ret;
918 }
919 
920 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
921 				      struct perf_event_attr *attr,
922 				      struct perf_event *group_leader)
923 {
924 	struct perf_cgroup *cgrp;
925 	struct cgroup_subsys_state *css;
926 	struct fd f = fdget(fd);
927 	int ret = 0;
928 
929 	if (!f.file)
930 		return -EBADF;
931 
932 	css = css_tryget_online_from_dir(f.file->f_path.dentry,
933 					 &perf_event_cgrp_subsys);
934 	if (IS_ERR(css)) {
935 		ret = PTR_ERR(css);
936 		goto out;
937 	}
938 
939 	ret = perf_cgroup_ensure_storage(event, css);
940 	if (ret)
941 		goto out;
942 
943 	cgrp = container_of(css, struct perf_cgroup, css);
944 	event->cgrp = cgrp;
945 
946 	/*
947 	 * all events in a group must monitor
948 	 * the same cgroup because a task belongs
949 	 * to only one perf cgroup at a time
950 	 */
951 	if (group_leader && group_leader->cgrp != cgrp) {
952 		perf_detach_cgroup(event);
953 		ret = -EINVAL;
954 	}
955 out:
956 	fdput(f);
957 	return ret;
958 }
959 
960 static inline void
961 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
962 {
963 	struct perf_cpu_context *cpuctx;
964 
965 	if (!is_cgroup_event(event))
966 		return;
967 
968 	/*
969 	 * Because cgroup events are always per-cpu events,
970 	 * @ctx == &cpuctx->ctx.
971 	 */
972 	cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
973 
974 	if (ctx->nr_cgroups++)
975 		return;
976 
977 	cpuctx->cgrp = perf_cgroup_from_task(current, ctx);
978 }
979 
980 static inline void
981 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
982 {
983 	struct perf_cpu_context *cpuctx;
984 
985 	if (!is_cgroup_event(event))
986 		return;
987 
988 	/*
989 	 * Because cgroup events are always per-cpu events,
990 	 * @ctx == &cpuctx->ctx.
991 	 */
992 	cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
993 
994 	if (--ctx->nr_cgroups)
995 		return;
996 
997 	cpuctx->cgrp = NULL;
998 }
999 
1000 #else /* !CONFIG_CGROUP_PERF */
1001 
1002 static inline bool
1003 perf_cgroup_match(struct perf_event *event)
1004 {
1005 	return true;
1006 }
1007 
1008 static inline void perf_detach_cgroup(struct perf_event *event)
1009 {}
1010 
1011 static inline int is_cgroup_event(struct perf_event *event)
1012 {
1013 	return 0;
1014 }
1015 
1016 static inline void update_cgrp_time_from_event(struct perf_event *event)
1017 {
1018 }
1019 
1020 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx,
1021 						bool final)
1022 {
1023 }
1024 
1025 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1026 				      struct perf_event_attr *attr,
1027 				      struct perf_event *group_leader)
1028 {
1029 	return -EINVAL;
1030 }
1031 
1032 static inline void
1033 perf_cgroup_set_timestamp(struct perf_cpu_context *cpuctx)
1034 {
1035 }
1036 
1037 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1038 {
1039 	return 0;
1040 }
1041 
1042 static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now)
1043 {
1044 	return 0;
1045 }
1046 
1047 static inline void
1048 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
1049 {
1050 }
1051 
1052 static inline void
1053 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
1054 {
1055 }
1056 
1057 static void perf_cgroup_switch(struct task_struct *task)
1058 {
1059 }
1060 #endif
1061 
1062 /*
1063  * set default to be dependent on timer tick just
1064  * like original code
1065  */
1066 #define PERF_CPU_HRTIMER (1000 / HZ)
1067 /*
1068  * function must be called with interrupts disabled
1069  */
1070 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1071 {
1072 	struct perf_cpu_pmu_context *cpc;
1073 	bool rotations;
1074 
1075 	lockdep_assert_irqs_disabled();
1076 
1077 	cpc = container_of(hr, struct perf_cpu_pmu_context, hrtimer);
1078 	rotations = perf_rotate_context(cpc);
1079 
1080 	raw_spin_lock(&cpc->hrtimer_lock);
1081 	if (rotations)
1082 		hrtimer_forward_now(hr, cpc->hrtimer_interval);
1083 	else
1084 		cpc->hrtimer_active = 0;
1085 	raw_spin_unlock(&cpc->hrtimer_lock);
1086 
1087 	return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1088 }
1089 
1090 static void __perf_mux_hrtimer_init(struct perf_cpu_pmu_context *cpc, int cpu)
1091 {
1092 	struct hrtimer *timer = &cpc->hrtimer;
1093 	struct pmu *pmu = cpc->epc.pmu;
1094 	u64 interval;
1095 
1096 	/*
1097 	 * check default is sane, if not set then force to
1098 	 * default interval (1/tick)
1099 	 */
1100 	interval = pmu->hrtimer_interval_ms;
1101 	if (interval < 1)
1102 		interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1103 
1104 	cpc->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1105 
1106 	raw_spin_lock_init(&cpc->hrtimer_lock);
1107 	hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
1108 	timer->function = perf_mux_hrtimer_handler;
1109 }
1110 
1111 static int perf_mux_hrtimer_restart(struct perf_cpu_pmu_context *cpc)
1112 {
1113 	struct hrtimer *timer = &cpc->hrtimer;
1114 	unsigned long flags;
1115 
1116 	raw_spin_lock_irqsave(&cpc->hrtimer_lock, flags);
1117 	if (!cpc->hrtimer_active) {
1118 		cpc->hrtimer_active = 1;
1119 		hrtimer_forward_now(timer, cpc->hrtimer_interval);
1120 		hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
1121 	}
1122 	raw_spin_unlock_irqrestore(&cpc->hrtimer_lock, flags);
1123 
1124 	return 0;
1125 }
1126 
1127 static int perf_mux_hrtimer_restart_ipi(void *arg)
1128 {
1129 	return perf_mux_hrtimer_restart(arg);
1130 }
1131 
1132 void perf_pmu_disable(struct pmu *pmu)
1133 {
1134 	int *count = this_cpu_ptr(pmu->pmu_disable_count);
1135 	if (!(*count)++)
1136 		pmu->pmu_disable(pmu);
1137 }
1138 
1139 void perf_pmu_enable(struct pmu *pmu)
1140 {
1141 	int *count = this_cpu_ptr(pmu->pmu_disable_count);
1142 	if (!--(*count))
1143 		pmu->pmu_enable(pmu);
1144 }
1145 
1146 static void perf_assert_pmu_disabled(struct pmu *pmu)
1147 {
1148 	WARN_ON_ONCE(*this_cpu_ptr(pmu->pmu_disable_count) == 0);
1149 }
1150 
1151 static void get_ctx(struct perf_event_context *ctx)
1152 {
1153 	refcount_inc(&ctx->refcount);
1154 }
1155 
1156 static void *alloc_task_ctx_data(struct pmu *pmu)
1157 {
1158 	if (pmu->task_ctx_cache)
1159 		return kmem_cache_zalloc(pmu->task_ctx_cache, GFP_KERNEL);
1160 
1161 	return NULL;
1162 }
1163 
1164 static void free_task_ctx_data(struct pmu *pmu, void *task_ctx_data)
1165 {
1166 	if (pmu->task_ctx_cache && task_ctx_data)
1167 		kmem_cache_free(pmu->task_ctx_cache, task_ctx_data);
1168 }
1169 
1170 static void free_ctx(struct rcu_head *head)
1171 {
1172 	struct perf_event_context *ctx;
1173 
1174 	ctx = container_of(head, struct perf_event_context, rcu_head);
1175 	kfree(ctx);
1176 }
1177 
1178 static void put_ctx(struct perf_event_context *ctx)
1179 {
1180 	if (refcount_dec_and_test(&ctx->refcount)) {
1181 		if (ctx->parent_ctx)
1182 			put_ctx(ctx->parent_ctx);
1183 		if (ctx->task && ctx->task != TASK_TOMBSTONE)
1184 			put_task_struct(ctx->task);
1185 		call_rcu(&ctx->rcu_head, free_ctx);
1186 	}
1187 }
1188 
1189 /*
1190  * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1191  * perf_pmu_migrate_context() we need some magic.
1192  *
1193  * Those places that change perf_event::ctx will hold both
1194  * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1195  *
1196  * Lock ordering is by mutex address. There are two other sites where
1197  * perf_event_context::mutex nests and those are:
1198  *
1199  *  - perf_event_exit_task_context()	[ child , 0 ]
1200  *      perf_event_exit_event()
1201  *        put_event()			[ parent, 1 ]
1202  *
1203  *  - perf_event_init_context()		[ parent, 0 ]
1204  *      inherit_task_group()
1205  *        inherit_group()
1206  *          inherit_event()
1207  *            perf_event_alloc()
1208  *              perf_init_event()
1209  *                perf_try_init_event()	[ child , 1 ]
1210  *
1211  * While it appears there is an obvious deadlock here -- the parent and child
1212  * nesting levels are inverted between the two. This is in fact safe because
1213  * life-time rules separate them. That is an exiting task cannot fork, and a
1214  * spawning task cannot (yet) exit.
1215  *
1216  * But remember that these are parent<->child context relations, and
1217  * migration does not affect children, therefore these two orderings should not
1218  * interact.
1219  *
1220  * The change in perf_event::ctx does not affect children (as claimed above)
1221  * because the sys_perf_event_open() case will install a new event and break
1222  * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1223  * concerned with cpuctx and that doesn't have children.
1224  *
1225  * The places that change perf_event::ctx will issue:
1226  *
1227  *   perf_remove_from_context();
1228  *   synchronize_rcu();
1229  *   perf_install_in_context();
1230  *
1231  * to affect the change. The remove_from_context() + synchronize_rcu() should
1232  * quiesce the event, after which we can install it in the new location. This
1233  * means that only external vectors (perf_fops, prctl) can perturb the event
1234  * while in transit. Therefore all such accessors should also acquire
1235  * perf_event_context::mutex to serialize against this.
1236  *
1237  * However; because event->ctx can change while we're waiting to acquire
1238  * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1239  * function.
1240  *
1241  * Lock order:
1242  *    exec_update_lock
1243  *	task_struct::perf_event_mutex
1244  *	  perf_event_context::mutex
1245  *	    perf_event::child_mutex;
1246  *	      perf_event_context::lock
1247  *	    perf_event::mmap_mutex
1248  *	    mmap_lock
1249  *	      perf_addr_filters_head::lock
1250  *
1251  *    cpu_hotplug_lock
1252  *      pmus_lock
1253  *	  cpuctx->mutex / perf_event_context::mutex
1254  */
1255 static struct perf_event_context *
1256 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1257 {
1258 	struct perf_event_context *ctx;
1259 
1260 again:
1261 	rcu_read_lock();
1262 	ctx = READ_ONCE(event->ctx);
1263 	if (!refcount_inc_not_zero(&ctx->refcount)) {
1264 		rcu_read_unlock();
1265 		goto again;
1266 	}
1267 	rcu_read_unlock();
1268 
1269 	mutex_lock_nested(&ctx->mutex, nesting);
1270 	if (event->ctx != ctx) {
1271 		mutex_unlock(&ctx->mutex);
1272 		put_ctx(ctx);
1273 		goto again;
1274 	}
1275 
1276 	return ctx;
1277 }
1278 
1279 static inline struct perf_event_context *
1280 perf_event_ctx_lock(struct perf_event *event)
1281 {
1282 	return perf_event_ctx_lock_nested(event, 0);
1283 }
1284 
1285 static void perf_event_ctx_unlock(struct perf_event *event,
1286 				  struct perf_event_context *ctx)
1287 {
1288 	mutex_unlock(&ctx->mutex);
1289 	put_ctx(ctx);
1290 }
1291 
1292 /*
1293  * This must be done under the ctx->lock, such as to serialize against
1294  * context_equiv(), therefore we cannot call put_ctx() since that might end up
1295  * calling scheduler related locks and ctx->lock nests inside those.
1296  */
1297 static __must_check struct perf_event_context *
1298 unclone_ctx(struct perf_event_context *ctx)
1299 {
1300 	struct perf_event_context *parent_ctx = ctx->parent_ctx;
1301 
1302 	lockdep_assert_held(&ctx->lock);
1303 
1304 	if (parent_ctx)
1305 		ctx->parent_ctx = NULL;
1306 	ctx->generation++;
1307 
1308 	return parent_ctx;
1309 }
1310 
1311 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1312 				enum pid_type type)
1313 {
1314 	u32 nr;
1315 	/*
1316 	 * only top level events have the pid namespace they were created in
1317 	 */
1318 	if (event->parent)
1319 		event = event->parent;
1320 
1321 	nr = __task_pid_nr_ns(p, type, event->ns);
1322 	/* avoid -1 if it is idle thread or runs in another ns */
1323 	if (!nr && !pid_alive(p))
1324 		nr = -1;
1325 	return nr;
1326 }
1327 
1328 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1329 {
1330 	return perf_event_pid_type(event, p, PIDTYPE_TGID);
1331 }
1332 
1333 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1334 {
1335 	return perf_event_pid_type(event, p, PIDTYPE_PID);
1336 }
1337 
1338 /*
1339  * If we inherit events we want to return the parent event id
1340  * to userspace.
1341  */
1342 static u64 primary_event_id(struct perf_event *event)
1343 {
1344 	u64 id = event->id;
1345 
1346 	if (event->parent)
1347 		id = event->parent->id;
1348 
1349 	return id;
1350 }
1351 
1352 /*
1353  * Get the perf_event_context for a task and lock it.
1354  *
1355  * This has to cope with the fact that until it is locked,
1356  * the context could get moved to another task.
1357  */
1358 static struct perf_event_context *
1359 perf_lock_task_context(struct task_struct *task, unsigned long *flags)
1360 {
1361 	struct perf_event_context *ctx;
1362 
1363 retry:
1364 	/*
1365 	 * One of the few rules of preemptible RCU is that one cannot do
1366 	 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1367 	 * part of the read side critical section was irqs-enabled -- see
1368 	 * rcu_read_unlock_special().
1369 	 *
1370 	 * Since ctx->lock nests under rq->lock we must ensure the entire read
1371 	 * side critical section has interrupts disabled.
1372 	 */
1373 	local_irq_save(*flags);
1374 	rcu_read_lock();
1375 	ctx = rcu_dereference(task->perf_event_ctxp);
1376 	if (ctx) {
1377 		/*
1378 		 * If this context is a clone of another, it might
1379 		 * get swapped for another underneath us by
1380 		 * perf_event_task_sched_out, though the
1381 		 * rcu_read_lock() protects us from any context
1382 		 * getting freed.  Lock the context and check if it
1383 		 * got swapped before we could get the lock, and retry
1384 		 * if so.  If we locked the right context, then it
1385 		 * can't get swapped on us any more.
1386 		 */
1387 		raw_spin_lock(&ctx->lock);
1388 		if (ctx != rcu_dereference(task->perf_event_ctxp)) {
1389 			raw_spin_unlock(&ctx->lock);
1390 			rcu_read_unlock();
1391 			local_irq_restore(*flags);
1392 			goto retry;
1393 		}
1394 
1395 		if (ctx->task == TASK_TOMBSTONE ||
1396 		    !refcount_inc_not_zero(&ctx->refcount)) {
1397 			raw_spin_unlock(&ctx->lock);
1398 			ctx = NULL;
1399 		} else {
1400 			WARN_ON_ONCE(ctx->task != task);
1401 		}
1402 	}
1403 	rcu_read_unlock();
1404 	if (!ctx)
1405 		local_irq_restore(*flags);
1406 	return ctx;
1407 }
1408 
1409 /*
1410  * Get the context for a task and increment its pin_count so it
1411  * can't get swapped to another task.  This also increments its
1412  * reference count so that the context can't get freed.
1413  */
1414 static struct perf_event_context *
1415 perf_pin_task_context(struct task_struct *task)
1416 {
1417 	struct perf_event_context *ctx;
1418 	unsigned long flags;
1419 
1420 	ctx = perf_lock_task_context(task, &flags);
1421 	if (ctx) {
1422 		++ctx->pin_count;
1423 		raw_spin_unlock_irqrestore(&ctx->lock, flags);
1424 	}
1425 	return ctx;
1426 }
1427 
1428 static void perf_unpin_context(struct perf_event_context *ctx)
1429 {
1430 	unsigned long flags;
1431 
1432 	raw_spin_lock_irqsave(&ctx->lock, flags);
1433 	--ctx->pin_count;
1434 	raw_spin_unlock_irqrestore(&ctx->lock, flags);
1435 }
1436 
1437 /*
1438  * Update the record of the current time in a context.
1439  */
1440 static void __update_context_time(struct perf_event_context *ctx, bool adv)
1441 {
1442 	u64 now = perf_clock();
1443 
1444 	lockdep_assert_held(&ctx->lock);
1445 
1446 	if (adv)
1447 		ctx->time += now - ctx->timestamp;
1448 	ctx->timestamp = now;
1449 
1450 	/*
1451 	 * The above: time' = time + (now - timestamp), can be re-arranged
1452 	 * into: time` = now + (time - timestamp), which gives a single value
1453 	 * offset to compute future time without locks on.
1454 	 *
1455 	 * See perf_event_time_now(), which can be used from NMI context where
1456 	 * it's (obviously) not possible to acquire ctx->lock in order to read
1457 	 * both the above values in a consistent manner.
1458 	 */
1459 	WRITE_ONCE(ctx->timeoffset, ctx->time - ctx->timestamp);
1460 }
1461 
1462 static void update_context_time(struct perf_event_context *ctx)
1463 {
1464 	__update_context_time(ctx, true);
1465 }
1466 
1467 static u64 perf_event_time(struct perf_event *event)
1468 {
1469 	struct perf_event_context *ctx = event->ctx;
1470 
1471 	if (unlikely(!ctx))
1472 		return 0;
1473 
1474 	if (is_cgroup_event(event))
1475 		return perf_cgroup_event_time(event);
1476 
1477 	return ctx->time;
1478 }
1479 
1480 static u64 perf_event_time_now(struct perf_event *event, u64 now)
1481 {
1482 	struct perf_event_context *ctx = event->ctx;
1483 
1484 	if (unlikely(!ctx))
1485 		return 0;
1486 
1487 	if (is_cgroup_event(event))
1488 		return perf_cgroup_event_time_now(event, now);
1489 
1490 	if (!(__load_acquire(&ctx->is_active) & EVENT_TIME))
1491 		return ctx->time;
1492 
1493 	now += READ_ONCE(ctx->timeoffset);
1494 	return now;
1495 }
1496 
1497 static enum event_type_t get_event_type(struct perf_event *event)
1498 {
1499 	struct perf_event_context *ctx = event->ctx;
1500 	enum event_type_t event_type;
1501 
1502 	lockdep_assert_held(&ctx->lock);
1503 
1504 	/*
1505 	 * It's 'group type', really, because if our group leader is
1506 	 * pinned, so are we.
1507 	 */
1508 	if (event->group_leader != event)
1509 		event = event->group_leader;
1510 
1511 	event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1512 	if (!ctx->task)
1513 		event_type |= EVENT_CPU;
1514 
1515 	return event_type;
1516 }
1517 
1518 /*
1519  * Helper function to initialize event group nodes.
1520  */
1521 static void init_event_group(struct perf_event *event)
1522 {
1523 	RB_CLEAR_NODE(&event->group_node);
1524 	event->group_index = 0;
1525 }
1526 
1527 /*
1528  * Extract pinned or flexible groups from the context
1529  * based on event attrs bits.
1530  */
1531 static struct perf_event_groups *
1532 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1533 {
1534 	if (event->attr.pinned)
1535 		return &ctx->pinned_groups;
1536 	else
1537 		return &ctx->flexible_groups;
1538 }
1539 
1540 /*
1541  * Helper function to initializes perf_event_group trees.
1542  */
1543 static void perf_event_groups_init(struct perf_event_groups *groups)
1544 {
1545 	groups->tree = RB_ROOT;
1546 	groups->index = 0;
1547 }
1548 
1549 static inline struct cgroup *event_cgroup(const struct perf_event *event)
1550 {
1551 	struct cgroup *cgroup = NULL;
1552 
1553 #ifdef CONFIG_CGROUP_PERF
1554 	if (event->cgrp)
1555 		cgroup = event->cgrp->css.cgroup;
1556 #endif
1557 
1558 	return cgroup;
1559 }
1560 
1561 /*
1562  * Compare function for event groups;
1563  *
1564  * Implements complex key that first sorts by CPU and then by virtual index
1565  * which provides ordering when rotating groups for the same CPU.
1566  */
1567 static __always_inline int
1568 perf_event_groups_cmp(const int left_cpu, const struct pmu *left_pmu,
1569 		      const struct cgroup *left_cgroup, const u64 left_group_index,
1570 		      const struct perf_event *right)
1571 {
1572 	if (left_cpu < right->cpu)
1573 		return -1;
1574 	if (left_cpu > right->cpu)
1575 		return 1;
1576 
1577 	if (left_pmu) {
1578 		if (left_pmu < right->pmu_ctx->pmu)
1579 			return -1;
1580 		if (left_pmu > right->pmu_ctx->pmu)
1581 			return 1;
1582 	}
1583 
1584 #ifdef CONFIG_CGROUP_PERF
1585 	{
1586 		const struct cgroup *right_cgroup = event_cgroup(right);
1587 
1588 		if (left_cgroup != right_cgroup) {
1589 			if (!left_cgroup) {
1590 				/*
1591 				 * Left has no cgroup but right does, no
1592 				 * cgroups come first.
1593 				 */
1594 				return -1;
1595 			}
1596 			if (!right_cgroup) {
1597 				/*
1598 				 * Right has no cgroup but left does, no
1599 				 * cgroups come first.
1600 				 */
1601 				return 1;
1602 			}
1603 			/* Two dissimilar cgroups, order by id. */
1604 			if (cgroup_id(left_cgroup) < cgroup_id(right_cgroup))
1605 				return -1;
1606 
1607 			return 1;
1608 		}
1609 	}
1610 #endif
1611 
1612 	if (left_group_index < right->group_index)
1613 		return -1;
1614 	if (left_group_index > right->group_index)
1615 		return 1;
1616 
1617 	return 0;
1618 }
1619 
1620 #define __node_2_pe(node) \
1621 	rb_entry((node), struct perf_event, group_node)
1622 
1623 static inline bool __group_less(struct rb_node *a, const struct rb_node *b)
1624 {
1625 	struct perf_event *e = __node_2_pe(a);
1626 	return perf_event_groups_cmp(e->cpu, e->pmu_ctx->pmu, event_cgroup(e),
1627 				     e->group_index, __node_2_pe(b)) < 0;
1628 }
1629 
1630 struct __group_key {
1631 	int cpu;
1632 	struct pmu *pmu;
1633 	struct cgroup *cgroup;
1634 };
1635 
1636 static inline int __group_cmp(const void *key, const struct rb_node *node)
1637 {
1638 	const struct __group_key *a = key;
1639 	const struct perf_event *b = __node_2_pe(node);
1640 
1641 	/* partial/subtree match: @cpu, @pmu, @cgroup; ignore: @group_index */
1642 	return perf_event_groups_cmp(a->cpu, a->pmu, a->cgroup, b->group_index, b);
1643 }
1644 
1645 static inline int
1646 __group_cmp_ignore_cgroup(const void *key, const struct rb_node *node)
1647 {
1648 	const struct __group_key *a = key;
1649 	const struct perf_event *b = __node_2_pe(node);
1650 
1651 	/* partial/subtree match: @cpu, @pmu, ignore: @cgroup, @group_index */
1652 	return perf_event_groups_cmp(a->cpu, a->pmu, event_cgroup(b),
1653 				     b->group_index, b);
1654 }
1655 
1656 /*
1657  * Insert @event into @groups' tree; using
1658  *   {@event->cpu, @event->pmu_ctx->pmu, event_cgroup(@event), ++@groups->index}
1659  * as key. This places it last inside the {cpu,pmu,cgroup} subtree.
1660  */
1661 static void
1662 perf_event_groups_insert(struct perf_event_groups *groups,
1663 			 struct perf_event *event)
1664 {
1665 	event->group_index = ++groups->index;
1666 
1667 	rb_add(&event->group_node, &groups->tree, __group_less);
1668 }
1669 
1670 /*
1671  * Helper function to insert event into the pinned or flexible groups.
1672  */
1673 static void
1674 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1675 {
1676 	struct perf_event_groups *groups;
1677 
1678 	groups = get_event_groups(event, ctx);
1679 	perf_event_groups_insert(groups, event);
1680 }
1681 
1682 /*
1683  * Delete a group from a tree.
1684  */
1685 static void
1686 perf_event_groups_delete(struct perf_event_groups *groups,
1687 			 struct perf_event *event)
1688 {
1689 	WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1690 		     RB_EMPTY_ROOT(&groups->tree));
1691 
1692 	rb_erase(&event->group_node, &groups->tree);
1693 	init_event_group(event);
1694 }
1695 
1696 /*
1697  * Helper function to delete event from its groups.
1698  */
1699 static void
1700 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1701 {
1702 	struct perf_event_groups *groups;
1703 
1704 	groups = get_event_groups(event, ctx);
1705 	perf_event_groups_delete(groups, event);
1706 }
1707 
1708 /*
1709  * Get the leftmost event in the {cpu,pmu,cgroup} subtree.
1710  */
1711 static struct perf_event *
1712 perf_event_groups_first(struct perf_event_groups *groups, int cpu,
1713 			struct pmu *pmu, struct cgroup *cgrp)
1714 {
1715 	struct __group_key key = {
1716 		.cpu = cpu,
1717 		.pmu = pmu,
1718 		.cgroup = cgrp,
1719 	};
1720 	struct rb_node *node;
1721 
1722 	node = rb_find_first(&key, &groups->tree, __group_cmp);
1723 	if (node)
1724 		return __node_2_pe(node);
1725 
1726 	return NULL;
1727 }
1728 
1729 static struct perf_event *
1730 perf_event_groups_next(struct perf_event *event, struct pmu *pmu)
1731 {
1732 	struct __group_key key = {
1733 		.cpu = event->cpu,
1734 		.pmu = pmu,
1735 		.cgroup = event_cgroup(event),
1736 	};
1737 	struct rb_node *next;
1738 
1739 	next = rb_next_match(&key, &event->group_node, __group_cmp);
1740 	if (next)
1741 		return __node_2_pe(next);
1742 
1743 	return NULL;
1744 }
1745 
1746 #define perf_event_groups_for_cpu_pmu(event, groups, cpu, pmu)		\
1747 	for (event = perf_event_groups_first(groups, cpu, pmu, NULL);	\
1748 	     event; event = perf_event_groups_next(event, pmu))
1749 
1750 /*
1751  * Iterate through the whole groups tree.
1752  */
1753 #define perf_event_groups_for_each(event, groups)			\
1754 	for (event = rb_entry_safe(rb_first(&((groups)->tree)),		\
1755 				typeof(*event), group_node); event;	\
1756 		event = rb_entry_safe(rb_next(&event->group_node),	\
1757 				typeof(*event), group_node))
1758 
1759 /*
1760  * Add an event from the lists for its context.
1761  * Must be called with ctx->mutex and ctx->lock held.
1762  */
1763 static void
1764 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1765 {
1766 	lockdep_assert_held(&ctx->lock);
1767 
1768 	WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1769 	event->attach_state |= PERF_ATTACH_CONTEXT;
1770 
1771 	event->tstamp = perf_event_time(event);
1772 
1773 	/*
1774 	 * If we're a stand alone event or group leader, we go to the context
1775 	 * list, group events are kept attached to the group so that
1776 	 * perf_group_detach can, at all times, locate all siblings.
1777 	 */
1778 	if (event->group_leader == event) {
1779 		event->group_caps = event->event_caps;
1780 		add_event_to_groups(event, ctx);
1781 	}
1782 
1783 	list_add_rcu(&event->event_entry, &ctx->event_list);
1784 	ctx->nr_events++;
1785 	if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
1786 		ctx->nr_user++;
1787 	if (event->attr.inherit_stat)
1788 		ctx->nr_stat++;
1789 
1790 	if (event->state > PERF_EVENT_STATE_OFF)
1791 		perf_cgroup_event_enable(event, ctx);
1792 
1793 	ctx->generation++;
1794 	event->pmu_ctx->nr_events++;
1795 }
1796 
1797 /*
1798  * Initialize event state based on the perf_event_attr::disabled.
1799  */
1800 static inline void perf_event__state_init(struct perf_event *event)
1801 {
1802 	event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1803 					      PERF_EVENT_STATE_INACTIVE;
1804 }
1805 
1806 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1807 {
1808 	int entry = sizeof(u64); /* value */
1809 	int size = 0;
1810 	int nr = 1;
1811 
1812 	if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1813 		size += sizeof(u64);
1814 
1815 	if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1816 		size += sizeof(u64);
1817 
1818 	if (event->attr.read_format & PERF_FORMAT_ID)
1819 		entry += sizeof(u64);
1820 
1821 	if (event->attr.read_format & PERF_FORMAT_LOST)
1822 		entry += sizeof(u64);
1823 
1824 	if (event->attr.read_format & PERF_FORMAT_GROUP) {
1825 		nr += nr_siblings;
1826 		size += sizeof(u64);
1827 	}
1828 
1829 	size += entry * nr;
1830 	event->read_size = size;
1831 }
1832 
1833 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1834 {
1835 	struct perf_sample_data *data;
1836 	u16 size = 0;
1837 
1838 	if (sample_type & PERF_SAMPLE_IP)
1839 		size += sizeof(data->ip);
1840 
1841 	if (sample_type & PERF_SAMPLE_ADDR)
1842 		size += sizeof(data->addr);
1843 
1844 	if (sample_type & PERF_SAMPLE_PERIOD)
1845 		size += sizeof(data->period);
1846 
1847 	if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
1848 		size += sizeof(data->weight.full);
1849 
1850 	if (sample_type & PERF_SAMPLE_READ)
1851 		size += event->read_size;
1852 
1853 	if (sample_type & PERF_SAMPLE_DATA_SRC)
1854 		size += sizeof(data->data_src.val);
1855 
1856 	if (sample_type & PERF_SAMPLE_TRANSACTION)
1857 		size += sizeof(data->txn);
1858 
1859 	if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1860 		size += sizeof(data->phys_addr);
1861 
1862 	if (sample_type & PERF_SAMPLE_CGROUP)
1863 		size += sizeof(data->cgroup);
1864 
1865 	if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
1866 		size += sizeof(data->data_page_size);
1867 
1868 	if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
1869 		size += sizeof(data->code_page_size);
1870 
1871 	event->header_size = size;
1872 }
1873 
1874 /*
1875  * Called at perf_event creation and when events are attached/detached from a
1876  * group.
1877  */
1878 static void perf_event__header_size(struct perf_event *event)
1879 {
1880 	__perf_event_read_size(event,
1881 			       event->group_leader->nr_siblings);
1882 	__perf_event_header_size(event, event->attr.sample_type);
1883 }
1884 
1885 static void perf_event__id_header_size(struct perf_event *event)
1886 {
1887 	struct perf_sample_data *data;
1888 	u64 sample_type = event->attr.sample_type;
1889 	u16 size = 0;
1890 
1891 	if (sample_type & PERF_SAMPLE_TID)
1892 		size += sizeof(data->tid_entry);
1893 
1894 	if (sample_type & PERF_SAMPLE_TIME)
1895 		size += sizeof(data->time);
1896 
1897 	if (sample_type & PERF_SAMPLE_IDENTIFIER)
1898 		size += sizeof(data->id);
1899 
1900 	if (sample_type & PERF_SAMPLE_ID)
1901 		size += sizeof(data->id);
1902 
1903 	if (sample_type & PERF_SAMPLE_STREAM_ID)
1904 		size += sizeof(data->stream_id);
1905 
1906 	if (sample_type & PERF_SAMPLE_CPU)
1907 		size += sizeof(data->cpu_entry);
1908 
1909 	event->id_header_size = size;
1910 }
1911 
1912 static bool perf_event_validate_size(struct perf_event *event)
1913 {
1914 	/*
1915 	 * The values computed here will be over-written when we actually
1916 	 * attach the event.
1917 	 */
1918 	__perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1919 	__perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1920 	perf_event__id_header_size(event);
1921 
1922 	/*
1923 	 * Sum the lot; should not exceed the 64k limit we have on records.
1924 	 * Conservative limit to allow for callchains and other variable fields.
1925 	 */
1926 	if (event->read_size + event->header_size +
1927 	    event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1928 		return false;
1929 
1930 	return true;
1931 }
1932 
1933 static void perf_group_attach(struct perf_event *event)
1934 {
1935 	struct perf_event *group_leader = event->group_leader, *pos;
1936 
1937 	lockdep_assert_held(&event->ctx->lock);
1938 
1939 	/*
1940 	 * We can have double attach due to group movement (move_group) in
1941 	 * perf_event_open().
1942 	 */
1943 	if (event->attach_state & PERF_ATTACH_GROUP)
1944 		return;
1945 
1946 	event->attach_state |= PERF_ATTACH_GROUP;
1947 
1948 	if (group_leader == event)
1949 		return;
1950 
1951 	WARN_ON_ONCE(group_leader->ctx != event->ctx);
1952 
1953 	group_leader->group_caps &= event->event_caps;
1954 
1955 	list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1956 	group_leader->nr_siblings++;
1957 
1958 	perf_event__header_size(group_leader);
1959 
1960 	for_each_sibling_event(pos, group_leader)
1961 		perf_event__header_size(pos);
1962 }
1963 
1964 /*
1965  * Remove an event from the lists for its context.
1966  * Must be called with ctx->mutex and ctx->lock held.
1967  */
1968 static void
1969 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1970 {
1971 	WARN_ON_ONCE(event->ctx != ctx);
1972 	lockdep_assert_held(&ctx->lock);
1973 
1974 	/*
1975 	 * We can have double detach due to exit/hot-unplug + close.
1976 	 */
1977 	if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1978 		return;
1979 
1980 	event->attach_state &= ~PERF_ATTACH_CONTEXT;
1981 
1982 	ctx->nr_events--;
1983 	if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
1984 		ctx->nr_user--;
1985 	if (event->attr.inherit_stat)
1986 		ctx->nr_stat--;
1987 
1988 	list_del_rcu(&event->event_entry);
1989 
1990 	if (event->group_leader == event)
1991 		del_event_from_groups(event, ctx);
1992 
1993 	/*
1994 	 * If event was in error state, then keep it
1995 	 * that way, otherwise bogus counts will be
1996 	 * returned on read(). The only way to get out
1997 	 * of error state is by explicit re-enabling
1998 	 * of the event
1999 	 */
2000 	if (event->state > PERF_EVENT_STATE_OFF) {
2001 		perf_cgroup_event_disable(event, ctx);
2002 		perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2003 	}
2004 
2005 	ctx->generation++;
2006 	event->pmu_ctx->nr_events--;
2007 }
2008 
2009 static int
2010 perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event)
2011 {
2012 	if (!has_aux(aux_event))
2013 		return 0;
2014 
2015 	if (!event->pmu->aux_output_match)
2016 		return 0;
2017 
2018 	return event->pmu->aux_output_match(aux_event);
2019 }
2020 
2021 static void put_event(struct perf_event *event);
2022 static void event_sched_out(struct perf_event *event,
2023 			    struct perf_event_context *ctx);
2024 
2025 static void perf_put_aux_event(struct perf_event *event)
2026 {
2027 	struct perf_event_context *ctx = event->ctx;
2028 	struct perf_event *iter;
2029 
2030 	/*
2031 	 * If event uses aux_event tear down the link
2032 	 */
2033 	if (event->aux_event) {
2034 		iter = event->aux_event;
2035 		event->aux_event = NULL;
2036 		put_event(iter);
2037 		return;
2038 	}
2039 
2040 	/*
2041 	 * If the event is an aux_event, tear down all links to
2042 	 * it from other events.
2043 	 */
2044 	for_each_sibling_event(iter, event->group_leader) {
2045 		if (iter->aux_event != event)
2046 			continue;
2047 
2048 		iter->aux_event = NULL;
2049 		put_event(event);
2050 
2051 		/*
2052 		 * If it's ACTIVE, schedule it out and put it into ERROR
2053 		 * state so that we don't try to schedule it again. Note
2054 		 * that perf_event_enable() will clear the ERROR status.
2055 		 */
2056 		event_sched_out(iter, ctx);
2057 		perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2058 	}
2059 }
2060 
2061 static bool perf_need_aux_event(struct perf_event *event)
2062 {
2063 	return !!event->attr.aux_output || !!event->attr.aux_sample_size;
2064 }
2065 
2066 static int perf_get_aux_event(struct perf_event *event,
2067 			      struct perf_event *group_leader)
2068 {
2069 	/*
2070 	 * Our group leader must be an aux event if we want to be
2071 	 * an aux_output. This way, the aux event will precede its
2072 	 * aux_output events in the group, and therefore will always
2073 	 * schedule first.
2074 	 */
2075 	if (!group_leader)
2076 		return 0;
2077 
2078 	/*
2079 	 * aux_output and aux_sample_size are mutually exclusive.
2080 	 */
2081 	if (event->attr.aux_output && event->attr.aux_sample_size)
2082 		return 0;
2083 
2084 	if (event->attr.aux_output &&
2085 	    !perf_aux_output_match(event, group_leader))
2086 		return 0;
2087 
2088 	if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux)
2089 		return 0;
2090 
2091 	if (!atomic_long_inc_not_zero(&group_leader->refcount))
2092 		return 0;
2093 
2094 	/*
2095 	 * Link aux_outputs to their aux event; this is undone in
2096 	 * perf_group_detach() by perf_put_aux_event(). When the
2097 	 * group in torn down, the aux_output events loose their
2098 	 * link to the aux_event and can't schedule any more.
2099 	 */
2100 	event->aux_event = group_leader;
2101 
2102 	return 1;
2103 }
2104 
2105 static inline struct list_head *get_event_list(struct perf_event *event)
2106 {
2107 	return event->attr.pinned ? &event->pmu_ctx->pinned_active :
2108 				    &event->pmu_ctx->flexible_active;
2109 }
2110 
2111 /*
2112  * Events that have PERF_EV_CAP_SIBLING require being part of a group and
2113  * cannot exist on their own, schedule them out and move them into the ERROR
2114  * state. Also see _perf_event_enable(), it will not be able to recover
2115  * this ERROR state.
2116  */
2117 static inline void perf_remove_sibling_event(struct perf_event *event)
2118 {
2119 	event_sched_out(event, event->ctx);
2120 	perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2121 }
2122 
2123 static void perf_group_detach(struct perf_event *event)
2124 {
2125 	struct perf_event *leader = event->group_leader;
2126 	struct perf_event *sibling, *tmp;
2127 	struct perf_event_context *ctx = event->ctx;
2128 
2129 	lockdep_assert_held(&ctx->lock);
2130 
2131 	/*
2132 	 * We can have double detach due to exit/hot-unplug + close.
2133 	 */
2134 	if (!(event->attach_state & PERF_ATTACH_GROUP))
2135 		return;
2136 
2137 	event->attach_state &= ~PERF_ATTACH_GROUP;
2138 
2139 	perf_put_aux_event(event);
2140 
2141 	/*
2142 	 * If this is a sibling, remove it from its group.
2143 	 */
2144 	if (leader != event) {
2145 		list_del_init(&event->sibling_list);
2146 		event->group_leader->nr_siblings--;
2147 		goto out;
2148 	}
2149 
2150 	/*
2151 	 * If this was a group event with sibling events then
2152 	 * upgrade the siblings to singleton events by adding them
2153 	 * to whatever list we are on.
2154 	 */
2155 	list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
2156 
2157 		if (sibling->event_caps & PERF_EV_CAP_SIBLING)
2158 			perf_remove_sibling_event(sibling);
2159 
2160 		sibling->group_leader = sibling;
2161 		list_del_init(&sibling->sibling_list);
2162 
2163 		/* Inherit group flags from the previous leader */
2164 		sibling->group_caps = event->group_caps;
2165 
2166 		if (!RB_EMPTY_NODE(&event->group_node)) {
2167 			add_event_to_groups(sibling, event->ctx);
2168 
2169 			if (sibling->state == PERF_EVENT_STATE_ACTIVE)
2170 				list_add_tail(&sibling->active_list, get_event_list(sibling));
2171 		}
2172 
2173 		WARN_ON_ONCE(sibling->ctx != event->ctx);
2174 	}
2175 
2176 out:
2177 	for_each_sibling_event(tmp, leader)
2178 		perf_event__header_size(tmp);
2179 
2180 	perf_event__header_size(leader);
2181 }
2182 
2183 static void sync_child_event(struct perf_event *child_event);
2184 
2185 static void perf_child_detach(struct perf_event *event)
2186 {
2187 	struct perf_event *parent_event = event->parent;
2188 
2189 	if (!(event->attach_state & PERF_ATTACH_CHILD))
2190 		return;
2191 
2192 	event->attach_state &= ~PERF_ATTACH_CHILD;
2193 
2194 	if (WARN_ON_ONCE(!parent_event))
2195 		return;
2196 
2197 	lockdep_assert_held(&parent_event->child_mutex);
2198 
2199 	sync_child_event(event);
2200 	list_del_init(&event->child_list);
2201 }
2202 
2203 static bool is_orphaned_event(struct perf_event *event)
2204 {
2205 	return event->state == PERF_EVENT_STATE_DEAD;
2206 }
2207 
2208 static inline int
2209 event_filter_match(struct perf_event *event)
2210 {
2211 	return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
2212 	       perf_cgroup_match(event);
2213 }
2214 
2215 static void
2216 event_sched_out(struct perf_event *event, struct perf_event_context *ctx)
2217 {
2218 	struct perf_event_pmu_context *epc = event->pmu_ctx;
2219 	struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context);
2220 	enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
2221 
2222 	// XXX cpc serialization, probably per-cpu IRQ disabled
2223 
2224 	WARN_ON_ONCE(event->ctx != ctx);
2225 	lockdep_assert_held(&ctx->lock);
2226 
2227 	if (event->state != PERF_EVENT_STATE_ACTIVE)
2228 		return;
2229 
2230 	/*
2231 	 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2232 	 * we can schedule events _OUT_ individually through things like
2233 	 * __perf_remove_from_context().
2234 	 */
2235 	list_del_init(&event->active_list);
2236 
2237 	perf_pmu_disable(event->pmu);
2238 
2239 	event->pmu->del(event, 0);
2240 	event->oncpu = -1;
2241 
2242 	if (event->pending_disable) {
2243 		event->pending_disable = 0;
2244 		perf_cgroup_event_disable(event, ctx);
2245 		state = PERF_EVENT_STATE_OFF;
2246 	}
2247 
2248 	if (event->pending_sigtrap) {
2249 		bool dec = true;
2250 
2251 		event->pending_sigtrap = 0;
2252 		if (state != PERF_EVENT_STATE_OFF &&
2253 		    !event->pending_work) {
2254 			event->pending_work = 1;
2255 			dec = false;
2256 			WARN_ON_ONCE(!atomic_long_inc_not_zero(&event->refcount));
2257 			task_work_add(current, &event->pending_task, TWA_RESUME);
2258 		}
2259 		if (dec)
2260 			local_dec(&event->ctx->nr_pending);
2261 	}
2262 
2263 	perf_event_set_state(event, state);
2264 
2265 	if (!is_software_event(event))
2266 		cpc->active_oncpu--;
2267 	if (event->attr.freq && event->attr.sample_freq)
2268 		ctx->nr_freq--;
2269 	if (event->attr.exclusive || !cpc->active_oncpu)
2270 		cpc->exclusive = 0;
2271 
2272 	perf_pmu_enable(event->pmu);
2273 }
2274 
2275 static void
2276 group_sched_out(struct perf_event *group_event, struct perf_event_context *ctx)
2277 {
2278 	struct perf_event *event;
2279 
2280 	if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2281 		return;
2282 
2283 	perf_assert_pmu_disabled(group_event->pmu_ctx->pmu);
2284 
2285 	event_sched_out(group_event, ctx);
2286 
2287 	/*
2288 	 * Schedule out siblings (if any):
2289 	 */
2290 	for_each_sibling_event(event, group_event)
2291 		event_sched_out(event, ctx);
2292 }
2293 
2294 #define DETACH_GROUP	0x01UL
2295 #define DETACH_CHILD	0x02UL
2296 #define DETACH_DEAD	0x04UL
2297 
2298 /*
2299  * Cross CPU call to remove a performance event
2300  *
2301  * We disable the event on the hardware level first. After that we
2302  * remove it from the context list.
2303  */
2304 static void
2305 __perf_remove_from_context(struct perf_event *event,
2306 			   struct perf_cpu_context *cpuctx,
2307 			   struct perf_event_context *ctx,
2308 			   void *info)
2309 {
2310 	struct perf_event_pmu_context *pmu_ctx = event->pmu_ctx;
2311 	unsigned long flags = (unsigned long)info;
2312 
2313 	if (ctx->is_active & EVENT_TIME) {
2314 		update_context_time(ctx);
2315 		update_cgrp_time_from_cpuctx(cpuctx, false);
2316 	}
2317 
2318 	/*
2319 	 * Ensure event_sched_out() switches to OFF, at the very least
2320 	 * this avoids raising perf_pending_task() at this time.
2321 	 */
2322 	if (flags & DETACH_DEAD)
2323 		event->pending_disable = 1;
2324 	event_sched_out(event, ctx);
2325 	if (flags & DETACH_GROUP)
2326 		perf_group_detach(event);
2327 	if (flags & DETACH_CHILD)
2328 		perf_child_detach(event);
2329 	list_del_event(event, ctx);
2330 	if (flags & DETACH_DEAD)
2331 		event->state = PERF_EVENT_STATE_DEAD;
2332 
2333 	if (!pmu_ctx->nr_events) {
2334 		pmu_ctx->rotate_necessary = 0;
2335 
2336 		if (ctx->task && ctx->is_active) {
2337 			struct perf_cpu_pmu_context *cpc;
2338 
2339 			cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context);
2340 			WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx);
2341 			cpc->task_epc = NULL;
2342 		}
2343 	}
2344 
2345 	if (!ctx->nr_events && ctx->is_active) {
2346 		if (ctx == &cpuctx->ctx)
2347 			update_cgrp_time_from_cpuctx(cpuctx, true);
2348 
2349 		ctx->is_active = 0;
2350 		if (ctx->task) {
2351 			WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2352 			cpuctx->task_ctx = NULL;
2353 		}
2354 	}
2355 }
2356 
2357 /*
2358  * Remove the event from a task's (or a CPU's) list of events.
2359  *
2360  * If event->ctx is a cloned context, callers must make sure that
2361  * every task struct that event->ctx->task could possibly point to
2362  * remains valid.  This is OK when called from perf_release since
2363  * that only calls us on the top-level context, which can't be a clone.
2364  * When called from perf_event_exit_task, it's OK because the
2365  * context has been detached from its task.
2366  */
2367 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2368 {
2369 	struct perf_event_context *ctx = event->ctx;
2370 
2371 	lockdep_assert_held(&ctx->mutex);
2372 
2373 	/*
2374 	 * Because of perf_event_exit_task(), perf_remove_from_context() ought
2375 	 * to work in the face of TASK_TOMBSTONE, unlike every other
2376 	 * event_function_call() user.
2377 	 */
2378 	raw_spin_lock_irq(&ctx->lock);
2379 	if (!ctx->is_active) {
2380 		__perf_remove_from_context(event, this_cpu_ptr(&perf_cpu_context),
2381 					   ctx, (void *)flags);
2382 		raw_spin_unlock_irq(&ctx->lock);
2383 		return;
2384 	}
2385 	raw_spin_unlock_irq(&ctx->lock);
2386 
2387 	event_function_call(event, __perf_remove_from_context, (void *)flags);
2388 }
2389 
2390 /*
2391  * Cross CPU call to disable a performance event
2392  */
2393 static void __perf_event_disable(struct perf_event *event,
2394 				 struct perf_cpu_context *cpuctx,
2395 				 struct perf_event_context *ctx,
2396 				 void *info)
2397 {
2398 	if (event->state < PERF_EVENT_STATE_INACTIVE)
2399 		return;
2400 
2401 	if (ctx->is_active & EVENT_TIME) {
2402 		update_context_time(ctx);
2403 		update_cgrp_time_from_event(event);
2404 	}
2405 
2406 	perf_pmu_disable(event->pmu_ctx->pmu);
2407 
2408 	if (event == event->group_leader)
2409 		group_sched_out(event, ctx);
2410 	else
2411 		event_sched_out(event, ctx);
2412 
2413 	perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2414 	perf_cgroup_event_disable(event, ctx);
2415 
2416 	perf_pmu_enable(event->pmu_ctx->pmu);
2417 }
2418 
2419 /*
2420  * Disable an event.
2421  *
2422  * If event->ctx is a cloned context, callers must make sure that
2423  * every task struct that event->ctx->task could possibly point to
2424  * remains valid.  This condition is satisfied when called through
2425  * perf_event_for_each_child or perf_event_for_each because they
2426  * hold the top-level event's child_mutex, so any descendant that
2427  * goes to exit will block in perf_event_exit_event().
2428  *
2429  * When called from perf_pending_irq it's OK because event->ctx
2430  * is the current context on this CPU and preemption is disabled,
2431  * hence we can't get into perf_event_task_sched_out for this context.
2432  */
2433 static void _perf_event_disable(struct perf_event *event)
2434 {
2435 	struct perf_event_context *ctx = event->ctx;
2436 
2437 	raw_spin_lock_irq(&ctx->lock);
2438 	if (event->state <= PERF_EVENT_STATE_OFF) {
2439 		raw_spin_unlock_irq(&ctx->lock);
2440 		return;
2441 	}
2442 	raw_spin_unlock_irq(&ctx->lock);
2443 
2444 	event_function_call(event, __perf_event_disable, NULL);
2445 }
2446 
2447 void perf_event_disable_local(struct perf_event *event)
2448 {
2449 	event_function_local(event, __perf_event_disable, NULL);
2450 }
2451 
2452 /*
2453  * Strictly speaking kernel users cannot create groups and therefore this
2454  * interface does not need the perf_event_ctx_lock() magic.
2455  */
2456 void perf_event_disable(struct perf_event *event)
2457 {
2458 	struct perf_event_context *ctx;
2459 
2460 	ctx = perf_event_ctx_lock(event);
2461 	_perf_event_disable(event);
2462 	perf_event_ctx_unlock(event, ctx);
2463 }
2464 EXPORT_SYMBOL_GPL(perf_event_disable);
2465 
2466 void perf_event_disable_inatomic(struct perf_event *event)
2467 {
2468 	event->pending_disable = 1;
2469 	irq_work_queue(&event->pending_irq);
2470 }
2471 
2472 #define MAX_INTERRUPTS (~0ULL)
2473 
2474 static void perf_log_throttle(struct perf_event *event, int enable);
2475 static void perf_log_itrace_start(struct perf_event *event);
2476 
2477 static int
2478 event_sched_in(struct perf_event *event, struct perf_event_context *ctx)
2479 {
2480 	struct perf_event_pmu_context *epc = event->pmu_ctx;
2481 	struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context);
2482 	int ret = 0;
2483 
2484 	WARN_ON_ONCE(event->ctx != ctx);
2485 
2486 	lockdep_assert_held(&ctx->lock);
2487 
2488 	if (event->state <= PERF_EVENT_STATE_OFF)
2489 		return 0;
2490 
2491 	WRITE_ONCE(event->oncpu, smp_processor_id());
2492 	/*
2493 	 * Order event::oncpu write to happen before the ACTIVE state is
2494 	 * visible. This allows perf_event_{stop,read}() to observe the correct
2495 	 * ->oncpu if it sees ACTIVE.
2496 	 */
2497 	smp_wmb();
2498 	perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2499 
2500 	/*
2501 	 * Unthrottle events, since we scheduled we might have missed several
2502 	 * ticks already, also for a heavily scheduling task there is little
2503 	 * guarantee it'll get a tick in a timely manner.
2504 	 */
2505 	if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2506 		perf_log_throttle(event, 1);
2507 		event->hw.interrupts = 0;
2508 	}
2509 
2510 	perf_pmu_disable(event->pmu);
2511 
2512 	perf_log_itrace_start(event);
2513 
2514 	if (event->pmu->add(event, PERF_EF_START)) {
2515 		perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2516 		event->oncpu = -1;
2517 		ret = -EAGAIN;
2518 		goto out;
2519 	}
2520 
2521 	if (!is_software_event(event))
2522 		cpc->active_oncpu++;
2523 	if (event->attr.freq && event->attr.sample_freq)
2524 		ctx->nr_freq++;
2525 
2526 	if (event->attr.exclusive)
2527 		cpc->exclusive = 1;
2528 
2529 out:
2530 	perf_pmu_enable(event->pmu);
2531 
2532 	return ret;
2533 }
2534 
2535 static int
2536 group_sched_in(struct perf_event *group_event, struct perf_event_context *ctx)
2537 {
2538 	struct perf_event *event, *partial_group = NULL;
2539 	struct pmu *pmu = group_event->pmu_ctx->pmu;
2540 
2541 	if (group_event->state == PERF_EVENT_STATE_OFF)
2542 		return 0;
2543 
2544 	pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2545 
2546 	if (event_sched_in(group_event, ctx))
2547 		goto error;
2548 
2549 	/*
2550 	 * Schedule in siblings as one group (if any):
2551 	 */
2552 	for_each_sibling_event(event, group_event) {
2553 		if (event_sched_in(event, ctx)) {
2554 			partial_group = event;
2555 			goto group_error;
2556 		}
2557 	}
2558 
2559 	if (!pmu->commit_txn(pmu))
2560 		return 0;
2561 
2562 group_error:
2563 	/*
2564 	 * Groups can be scheduled in as one unit only, so undo any
2565 	 * partial group before returning:
2566 	 * The events up to the failed event are scheduled out normally.
2567 	 */
2568 	for_each_sibling_event(event, group_event) {
2569 		if (event == partial_group)
2570 			break;
2571 
2572 		event_sched_out(event, ctx);
2573 	}
2574 	event_sched_out(group_event, ctx);
2575 
2576 error:
2577 	pmu->cancel_txn(pmu);
2578 	return -EAGAIN;
2579 }
2580 
2581 /*
2582  * Work out whether we can put this event group on the CPU now.
2583  */
2584 static int group_can_go_on(struct perf_event *event, int can_add_hw)
2585 {
2586 	struct perf_event_pmu_context *epc = event->pmu_ctx;
2587 	struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context);
2588 
2589 	/*
2590 	 * Groups consisting entirely of software events can always go on.
2591 	 */
2592 	if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2593 		return 1;
2594 	/*
2595 	 * If an exclusive group is already on, no other hardware
2596 	 * events can go on.
2597 	 */
2598 	if (cpc->exclusive)
2599 		return 0;
2600 	/*
2601 	 * If this group is exclusive and there are already
2602 	 * events on the CPU, it can't go on.
2603 	 */
2604 	if (event->attr.exclusive && !list_empty(get_event_list(event)))
2605 		return 0;
2606 	/*
2607 	 * Otherwise, try to add it if all previous groups were able
2608 	 * to go on.
2609 	 */
2610 	return can_add_hw;
2611 }
2612 
2613 static void add_event_to_ctx(struct perf_event *event,
2614 			       struct perf_event_context *ctx)
2615 {
2616 	list_add_event(event, ctx);
2617 	perf_group_attach(event);
2618 }
2619 
2620 static void task_ctx_sched_out(struct perf_event_context *ctx,
2621 				enum event_type_t event_type)
2622 {
2623 	struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
2624 
2625 	if (!cpuctx->task_ctx)
2626 		return;
2627 
2628 	if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2629 		return;
2630 
2631 	ctx_sched_out(ctx, event_type);
2632 }
2633 
2634 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2635 				struct perf_event_context *ctx)
2636 {
2637 	ctx_sched_in(&cpuctx->ctx, EVENT_PINNED);
2638 	if (ctx)
2639 		 ctx_sched_in(ctx, EVENT_PINNED);
2640 	ctx_sched_in(&cpuctx->ctx, EVENT_FLEXIBLE);
2641 	if (ctx)
2642 		 ctx_sched_in(ctx, EVENT_FLEXIBLE);
2643 }
2644 
2645 /*
2646  * We want to maintain the following priority of scheduling:
2647  *  - CPU pinned (EVENT_CPU | EVENT_PINNED)
2648  *  - task pinned (EVENT_PINNED)
2649  *  - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2650  *  - task flexible (EVENT_FLEXIBLE).
2651  *
2652  * In order to avoid unscheduling and scheduling back in everything every
2653  * time an event is added, only do it for the groups of equal priority and
2654  * below.
2655  *
2656  * This can be called after a batch operation on task events, in which case
2657  * event_type is a bit mask of the types of events involved. For CPU events,
2658  * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2659  */
2660 /*
2661  * XXX: ctx_resched() reschedule entire perf_event_context while adding new
2662  * event to the context or enabling existing event in the context. We can
2663  * probably optimize it by rescheduling only affected pmu_ctx.
2664  */
2665 static void ctx_resched(struct perf_cpu_context *cpuctx,
2666 			struct perf_event_context *task_ctx,
2667 			enum event_type_t event_type)
2668 {
2669 	bool cpu_event = !!(event_type & EVENT_CPU);
2670 
2671 	/*
2672 	 * If pinned groups are involved, flexible groups also need to be
2673 	 * scheduled out.
2674 	 */
2675 	if (event_type & EVENT_PINNED)
2676 		event_type |= EVENT_FLEXIBLE;
2677 
2678 	event_type &= EVENT_ALL;
2679 
2680 	perf_ctx_disable(&cpuctx->ctx);
2681 	if (task_ctx) {
2682 		perf_ctx_disable(task_ctx);
2683 		task_ctx_sched_out(task_ctx, event_type);
2684 	}
2685 
2686 	/*
2687 	 * Decide which cpu ctx groups to schedule out based on the types
2688 	 * of events that caused rescheduling:
2689 	 *  - EVENT_CPU: schedule out corresponding groups;
2690 	 *  - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2691 	 *  - otherwise, do nothing more.
2692 	 */
2693 	if (cpu_event)
2694 		ctx_sched_out(&cpuctx->ctx, event_type);
2695 	else if (event_type & EVENT_PINNED)
2696 		ctx_sched_out(&cpuctx->ctx, EVENT_FLEXIBLE);
2697 
2698 	perf_event_sched_in(cpuctx, task_ctx);
2699 
2700 	perf_ctx_enable(&cpuctx->ctx);
2701 	if (task_ctx)
2702 		perf_ctx_enable(task_ctx);
2703 }
2704 
2705 void perf_pmu_resched(struct pmu *pmu)
2706 {
2707 	struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
2708 	struct perf_event_context *task_ctx = cpuctx->task_ctx;
2709 
2710 	perf_ctx_lock(cpuctx, task_ctx);
2711 	ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2712 	perf_ctx_unlock(cpuctx, task_ctx);
2713 }
2714 
2715 /*
2716  * Cross CPU call to install and enable a performance event
2717  *
2718  * Very similar to remote_function() + event_function() but cannot assume that
2719  * things like ctx->is_active and cpuctx->task_ctx are set.
2720  */
2721 static int  __perf_install_in_context(void *info)
2722 {
2723 	struct perf_event *event = info;
2724 	struct perf_event_context *ctx = event->ctx;
2725 	struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
2726 	struct perf_event_context *task_ctx = cpuctx->task_ctx;
2727 	bool reprogram = true;
2728 	int ret = 0;
2729 
2730 	raw_spin_lock(&cpuctx->ctx.lock);
2731 	if (ctx->task) {
2732 		raw_spin_lock(&ctx->lock);
2733 		task_ctx = ctx;
2734 
2735 		reprogram = (ctx->task == current);
2736 
2737 		/*
2738 		 * If the task is running, it must be running on this CPU,
2739 		 * otherwise we cannot reprogram things.
2740 		 *
2741 		 * If its not running, we don't care, ctx->lock will
2742 		 * serialize against it becoming runnable.
2743 		 */
2744 		if (task_curr(ctx->task) && !reprogram) {
2745 			ret = -ESRCH;
2746 			goto unlock;
2747 		}
2748 
2749 		WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2750 	} else if (task_ctx) {
2751 		raw_spin_lock(&task_ctx->lock);
2752 	}
2753 
2754 #ifdef CONFIG_CGROUP_PERF
2755 	if (event->state > PERF_EVENT_STATE_OFF && is_cgroup_event(event)) {
2756 		/*
2757 		 * If the current cgroup doesn't match the event's
2758 		 * cgroup, we should not try to schedule it.
2759 		 */
2760 		struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2761 		reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2762 					event->cgrp->css.cgroup);
2763 	}
2764 #endif
2765 
2766 	if (reprogram) {
2767 		ctx_sched_out(ctx, EVENT_TIME);
2768 		add_event_to_ctx(event, ctx);
2769 		ctx_resched(cpuctx, task_ctx, get_event_type(event));
2770 	} else {
2771 		add_event_to_ctx(event, ctx);
2772 	}
2773 
2774 unlock:
2775 	perf_ctx_unlock(cpuctx, task_ctx);
2776 
2777 	return ret;
2778 }
2779 
2780 static bool exclusive_event_installable(struct perf_event *event,
2781 					struct perf_event_context *ctx);
2782 
2783 /*
2784  * Attach a performance event to a context.
2785  *
2786  * Very similar to event_function_call, see comment there.
2787  */
2788 static void
2789 perf_install_in_context(struct perf_event_context *ctx,
2790 			struct perf_event *event,
2791 			int cpu)
2792 {
2793 	struct task_struct *task = READ_ONCE(ctx->task);
2794 
2795 	lockdep_assert_held(&ctx->mutex);
2796 
2797 	WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2798 
2799 	if (event->cpu != -1)
2800 		WARN_ON_ONCE(event->cpu != cpu);
2801 
2802 	/*
2803 	 * Ensures that if we can observe event->ctx, both the event and ctx
2804 	 * will be 'complete'. See perf_iterate_sb_cpu().
2805 	 */
2806 	smp_store_release(&event->ctx, ctx);
2807 
2808 	/*
2809 	 * perf_event_attr::disabled events will not run and can be initialized
2810 	 * without IPI. Except when this is the first event for the context, in
2811 	 * that case we need the magic of the IPI to set ctx->is_active.
2812 	 *
2813 	 * The IOC_ENABLE that is sure to follow the creation of a disabled
2814 	 * event will issue the IPI and reprogram the hardware.
2815 	 */
2816 	if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF &&
2817 	    ctx->nr_events && !is_cgroup_event(event)) {
2818 		raw_spin_lock_irq(&ctx->lock);
2819 		if (ctx->task == TASK_TOMBSTONE) {
2820 			raw_spin_unlock_irq(&ctx->lock);
2821 			return;
2822 		}
2823 		add_event_to_ctx(event, ctx);
2824 		raw_spin_unlock_irq(&ctx->lock);
2825 		return;
2826 	}
2827 
2828 	if (!task) {
2829 		cpu_function_call(cpu, __perf_install_in_context, event);
2830 		return;
2831 	}
2832 
2833 	/*
2834 	 * Should not happen, we validate the ctx is still alive before calling.
2835 	 */
2836 	if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2837 		return;
2838 
2839 	/*
2840 	 * Installing events is tricky because we cannot rely on ctx->is_active
2841 	 * to be set in case this is the nr_events 0 -> 1 transition.
2842 	 *
2843 	 * Instead we use task_curr(), which tells us if the task is running.
2844 	 * However, since we use task_curr() outside of rq::lock, we can race
2845 	 * against the actual state. This means the result can be wrong.
2846 	 *
2847 	 * If we get a false positive, we retry, this is harmless.
2848 	 *
2849 	 * If we get a false negative, things are complicated. If we are after
2850 	 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2851 	 * value must be correct. If we're before, it doesn't matter since
2852 	 * perf_event_context_sched_in() will program the counter.
2853 	 *
2854 	 * However, this hinges on the remote context switch having observed
2855 	 * our task->perf_event_ctxp[] store, such that it will in fact take
2856 	 * ctx::lock in perf_event_context_sched_in().
2857 	 *
2858 	 * We do this by task_function_call(), if the IPI fails to hit the task
2859 	 * we know any future context switch of task must see the
2860 	 * perf_event_ctpx[] store.
2861 	 */
2862 
2863 	/*
2864 	 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2865 	 * task_cpu() load, such that if the IPI then does not find the task
2866 	 * running, a future context switch of that task must observe the
2867 	 * store.
2868 	 */
2869 	smp_mb();
2870 again:
2871 	if (!task_function_call(task, __perf_install_in_context, event))
2872 		return;
2873 
2874 	raw_spin_lock_irq(&ctx->lock);
2875 	task = ctx->task;
2876 	if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2877 		/*
2878 		 * Cannot happen because we already checked above (which also
2879 		 * cannot happen), and we hold ctx->mutex, which serializes us
2880 		 * against perf_event_exit_task_context().
2881 		 */
2882 		raw_spin_unlock_irq(&ctx->lock);
2883 		return;
2884 	}
2885 	/*
2886 	 * If the task is not running, ctx->lock will avoid it becoming so,
2887 	 * thus we can safely install the event.
2888 	 */
2889 	if (task_curr(task)) {
2890 		raw_spin_unlock_irq(&ctx->lock);
2891 		goto again;
2892 	}
2893 	add_event_to_ctx(event, ctx);
2894 	raw_spin_unlock_irq(&ctx->lock);
2895 }
2896 
2897 /*
2898  * Cross CPU call to enable a performance event
2899  */
2900 static void __perf_event_enable(struct perf_event *event,
2901 				struct perf_cpu_context *cpuctx,
2902 				struct perf_event_context *ctx,
2903 				void *info)
2904 {
2905 	struct perf_event *leader = event->group_leader;
2906 	struct perf_event_context *task_ctx;
2907 
2908 	if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2909 	    event->state <= PERF_EVENT_STATE_ERROR)
2910 		return;
2911 
2912 	if (ctx->is_active)
2913 		ctx_sched_out(ctx, EVENT_TIME);
2914 
2915 	perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2916 	perf_cgroup_event_enable(event, ctx);
2917 
2918 	if (!ctx->is_active)
2919 		return;
2920 
2921 	if (!event_filter_match(event)) {
2922 		ctx_sched_in(ctx, EVENT_TIME);
2923 		return;
2924 	}
2925 
2926 	/*
2927 	 * If the event is in a group and isn't the group leader,
2928 	 * then don't put it on unless the group is on.
2929 	 */
2930 	if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2931 		ctx_sched_in(ctx, EVENT_TIME);
2932 		return;
2933 	}
2934 
2935 	task_ctx = cpuctx->task_ctx;
2936 	if (ctx->task)
2937 		WARN_ON_ONCE(task_ctx != ctx);
2938 
2939 	ctx_resched(cpuctx, task_ctx, get_event_type(event));
2940 }
2941 
2942 /*
2943  * Enable an event.
2944  *
2945  * If event->ctx is a cloned context, callers must make sure that
2946  * every task struct that event->ctx->task could possibly point to
2947  * remains valid.  This condition is satisfied when called through
2948  * perf_event_for_each_child or perf_event_for_each as described
2949  * for perf_event_disable.
2950  */
2951 static void _perf_event_enable(struct perf_event *event)
2952 {
2953 	struct perf_event_context *ctx = event->ctx;
2954 
2955 	raw_spin_lock_irq(&ctx->lock);
2956 	if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2957 	    event->state <  PERF_EVENT_STATE_ERROR) {
2958 out:
2959 		raw_spin_unlock_irq(&ctx->lock);
2960 		return;
2961 	}
2962 
2963 	/*
2964 	 * If the event is in error state, clear that first.
2965 	 *
2966 	 * That way, if we see the event in error state below, we know that it
2967 	 * has gone back into error state, as distinct from the task having
2968 	 * been scheduled away before the cross-call arrived.
2969 	 */
2970 	if (event->state == PERF_EVENT_STATE_ERROR) {
2971 		/*
2972 		 * Detached SIBLING events cannot leave ERROR state.
2973 		 */
2974 		if (event->event_caps & PERF_EV_CAP_SIBLING &&
2975 		    event->group_leader == event)
2976 			goto out;
2977 
2978 		event->state = PERF_EVENT_STATE_OFF;
2979 	}
2980 	raw_spin_unlock_irq(&ctx->lock);
2981 
2982 	event_function_call(event, __perf_event_enable, NULL);
2983 }
2984 
2985 /*
2986  * See perf_event_disable();
2987  */
2988 void perf_event_enable(struct perf_event *event)
2989 {
2990 	struct perf_event_context *ctx;
2991 
2992 	ctx = perf_event_ctx_lock(event);
2993 	_perf_event_enable(event);
2994 	perf_event_ctx_unlock(event, ctx);
2995 }
2996 EXPORT_SYMBOL_GPL(perf_event_enable);
2997 
2998 struct stop_event_data {
2999 	struct perf_event	*event;
3000 	unsigned int		restart;
3001 };
3002 
3003 static int __perf_event_stop(void *info)
3004 {
3005 	struct stop_event_data *sd = info;
3006 	struct perf_event *event = sd->event;
3007 
3008 	/* if it's already INACTIVE, do nothing */
3009 	if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3010 		return 0;
3011 
3012 	/* matches smp_wmb() in event_sched_in() */
3013 	smp_rmb();
3014 
3015 	/*
3016 	 * There is a window with interrupts enabled before we get here,
3017 	 * so we need to check again lest we try to stop another CPU's event.
3018 	 */
3019 	if (READ_ONCE(event->oncpu) != smp_processor_id())
3020 		return -EAGAIN;
3021 
3022 	event->pmu->stop(event, PERF_EF_UPDATE);
3023 
3024 	/*
3025 	 * May race with the actual stop (through perf_pmu_output_stop()),
3026 	 * but it is only used for events with AUX ring buffer, and such
3027 	 * events will refuse to restart because of rb::aux_mmap_count==0,
3028 	 * see comments in perf_aux_output_begin().
3029 	 *
3030 	 * Since this is happening on an event-local CPU, no trace is lost
3031 	 * while restarting.
3032 	 */
3033 	if (sd->restart)
3034 		event->pmu->start(event, 0);
3035 
3036 	return 0;
3037 }
3038 
3039 static int perf_event_stop(struct perf_event *event, int restart)
3040 {
3041 	struct stop_event_data sd = {
3042 		.event		= event,
3043 		.restart	= restart,
3044 	};
3045 	int ret = 0;
3046 
3047 	do {
3048 		if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3049 			return 0;
3050 
3051 		/* matches smp_wmb() in event_sched_in() */
3052 		smp_rmb();
3053 
3054 		/*
3055 		 * We only want to restart ACTIVE events, so if the event goes
3056 		 * inactive here (event->oncpu==-1), there's nothing more to do;
3057 		 * fall through with ret==-ENXIO.
3058 		 */
3059 		ret = cpu_function_call(READ_ONCE(event->oncpu),
3060 					__perf_event_stop, &sd);
3061 	} while (ret == -EAGAIN);
3062 
3063 	return ret;
3064 }
3065 
3066 /*
3067  * In order to contain the amount of racy and tricky in the address filter
3068  * configuration management, it is a two part process:
3069  *
3070  * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
3071  *      we update the addresses of corresponding vmas in
3072  *	event::addr_filter_ranges array and bump the event::addr_filters_gen;
3073  * (p2) when an event is scheduled in (pmu::add), it calls
3074  *      perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
3075  *      if the generation has changed since the previous call.
3076  *
3077  * If (p1) happens while the event is active, we restart it to force (p2).
3078  *
3079  * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
3080  *     pre-existing mappings, called once when new filters arrive via SET_FILTER
3081  *     ioctl;
3082  * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
3083  *     registered mapping, called for every new mmap(), with mm::mmap_lock down
3084  *     for reading;
3085  * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
3086  *     of exec.
3087  */
3088 void perf_event_addr_filters_sync(struct perf_event *event)
3089 {
3090 	struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
3091 
3092 	if (!has_addr_filter(event))
3093 		return;
3094 
3095 	raw_spin_lock(&ifh->lock);
3096 	if (event->addr_filters_gen != event->hw.addr_filters_gen) {
3097 		event->pmu->addr_filters_sync(event);
3098 		event->hw.addr_filters_gen = event->addr_filters_gen;
3099 	}
3100 	raw_spin_unlock(&ifh->lock);
3101 }
3102 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
3103 
3104 static int _perf_event_refresh(struct perf_event *event, int refresh)
3105 {
3106 	/*
3107 	 * not supported on inherited events
3108 	 */
3109 	if (event->attr.inherit || !is_sampling_event(event))
3110 		return -EINVAL;
3111 
3112 	atomic_add(refresh, &event->event_limit);
3113 	_perf_event_enable(event);
3114 
3115 	return 0;
3116 }
3117 
3118 /*
3119  * See perf_event_disable()
3120  */
3121 int perf_event_refresh(struct perf_event *event, int refresh)
3122 {
3123 	struct perf_event_context *ctx;
3124 	int ret;
3125 
3126 	ctx = perf_event_ctx_lock(event);
3127 	ret = _perf_event_refresh(event, refresh);
3128 	perf_event_ctx_unlock(event, ctx);
3129 
3130 	return ret;
3131 }
3132 EXPORT_SYMBOL_GPL(perf_event_refresh);
3133 
3134 static int perf_event_modify_breakpoint(struct perf_event *bp,
3135 					 struct perf_event_attr *attr)
3136 {
3137 	int err;
3138 
3139 	_perf_event_disable(bp);
3140 
3141 	err = modify_user_hw_breakpoint_check(bp, attr, true);
3142 
3143 	if (!bp->attr.disabled)
3144 		_perf_event_enable(bp);
3145 
3146 	return err;
3147 }
3148 
3149 /*
3150  * Copy event-type-independent attributes that may be modified.
3151  */
3152 static void perf_event_modify_copy_attr(struct perf_event_attr *to,
3153 					const struct perf_event_attr *from)
3154 {
3155 	to->sig_data = from->sig_data;
3156 }
3157 
3158 static int perf_event_modify_attr(struct perf_event *event,
3159 				  struct perf_event_attr *attr)
3160 {
3161 	int (*func)(struct perf_event *, struct perf_event_attr *);
3162 	struct perf_event *child;
3163 	int err;
3164 
3165 	if (event->attr.type != attr->type)
3166 		return -EINVAL;
3167 
3168 	switch (event->attr.type) {
3169 	case PERF_TYPE_BREAKPOINT:
3170 		func = perf_event_modify_breakpoint;
3171 		break;
3172 	default:
3173 		/* Place holder for future additions. */
3174 		return -EOPNOTSUPP;
3175 	}
3176 
3177 	WARN_ON_ONCE(event->ctx->parent_ctx);
3178 
3179 	mutex_lock(&event->child_mutex);
3180 	/*
3181 	 * Event-type-independent attributes must be copied before event-type
3182 	 * modification, which will validate that final attributes match the
3183 	 * source attributes after all relevant attributes have been copied.
3184 	 */
3185 	perf_event_modify_copy_attr(&event->attr, attr);
3186 	err = func(event, attr);
3187 	if (err)
3188 		goto out;
3189 	list_for_each_entry(child, &event->child_list, child_list) {
3190 		perf_event_modify_copy_attr(&child->attr, attr);
3191 		err = func(child, attr);
3192 		if (err)
3193 			goto out;
3194 	}
3195 out:
3196 	mutex_unlock(&event->child_mutex);
3197 	return err;
3198 }
3199 
3200 static void __pmu_ctx_sched_out(struct perf_event_pmu_context *pmu_ctx,
3201 				enum event_type_t event_type)
3202 {
3203 	struct perf_event_context *ctx = pmu_ctx->ctx;
3204 	struct perf_event *event, *tmp;
3205 	struct pmu *pmu = pmu_ctx->pmu;
3206 
3207 	if (ctx->task && !ctx->is_active) {
3208 		struct perf_cpu_pmu_context *cpc;
3209 
3210 		cpc = this_cpu_ptr(pmu->cpu_pmu_context);
3211 		WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx);
3212 		cpc->task_epc = NULL;
3213 	}
3214 
3215 	if (!event_type)
3216 		return;
3217 
3218 	perf_pmu_disable(pmu);
3219 	if (event_type & EVENT_PINNED) {
3220 		list_for_each_entry_safe(event, tmp,
3221 					 &pmu_ctx->pinned_active,
3222 					 active_list)
3223 			group_sched_out(event, ctx);
3224 	}
3225 
3226 	if (event_type & EVENT_FLEXIBLE) {
3227 		list_for_each_entry_safe(event, tmp,
3228 					 &pmu_ctx->flexible_active,
3229 					 active_list)
3230 			group_sched_out(event, ctx);
3231 		/*
3232 		 * Since we cleared EVENT_FLEXIBLE, also clear
3233 		 * rotate_necessary, is will be reset by
3234 		 * ctx_flexible_sched_in() when needed.
3235 		 */
3236 		pmu_ctx->rotate_necessary = 0;
3237 	}
3238 	perf_pmu_enable(pmu);
3239 }
3240 
3241 static void
3242 ctx_sched_out(struct perf_event_context *ctx, enum event_type_t event_type)
3243 {
3244 	struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3245 	struct perf_event_pmu_context *pmu_ctx;
3246 	int is_active = ctx->is_active;
3247 
3248 	lockdep_assert_held(&ctx->lock);
3249 
3250 	if (likely(!ctx->nr_events)) {
3251 		/*
3252 		 * See __perf_remove_from_context().
3253 		 */
3254 		WARN_ON_ONCE(ctx->is_active);
3255 		if (ctx->task)
3256 			WARN_ON_ONCE(cpuctx->task_ctx);
3257 		return;
3258 	}
3259 
3260 	/*
3261 	 * Always update time if it was set; not only when it changes.
3262 	 * Otherwise we can 'forget' to update time for any but the last
3263 	 * context we sched out. For example:
3264 	 *
3265 	 *   ctx_sched_out(.event_type = EVENT_FLEXIBLE)
3266 	 *   ctx_sched_out(.event_type = EVENT_PINNED)
3267 	 *
3268 	 * would only update time for the pinned events.
3269 	 */
3270 	if (is_active & EVENT_TIME) {
3271 		/* update (and stop) ctx time */
3272 		update_context_time(ctx);
3273 		update_cgrp_time_from_cpuctx(cpuctx, ctx == &cpuctx->ctx);
3274 		/*
3275 		 * CPU-release for the below ->is_active store,
3276 		 * see __load_acquire() in perf_event_time_now()
3277 		 */
3278 		barrier();
3279 	}
3280 
3281 	ctx->is_active &= ~event_type;
3282 	if (!(ctx->is_active & EVENT_ALL))
3283 		ctx->is_active = 0;
3284 
3285 	if (ctx->task) {
3286 		WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3287 		if (!ctx->is_active)
3288 			cpuctx->task_ctx = NULL;
3289 	}
3290 
3291 	is_active ^= ctx->is_active; /* changed bits */
3292 
3293 	list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry)
3294 		__pmu_ctx_sched_out(pmu_ctx, is_active);
3295 }
3296 
3297 /*
3298  * Test whether two contexts are equivalent, i.e. whether they have both been
3299  * cloned from the same version of the same context.
3300  *
3301  * Equivalence is measured using a generation number in the context that is
3302  * incremented on each modification to it; see unclone_ctx(), list_add_event()
3303  * and list_del_event().
3304  */
3305 static int context_equiv(struct perf_event_context *ctx1,
3306 			 struct perf_event_context *ctx2)
3307 {
3308 	lockdep_assert_held(&ctx1->lock);
3309 	lockdep_assert_held(&ctx2->lock);
3310 
3311 	/* Pinning disables the swap optimization */
3312 	if (ctx1->pin_count || ctx2->pin_count)
3313 		return 0;
3314 
3315 	/* If ctx1 is the parent of ctx2 */
3316 	if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3317 		return 1;
3318 
3319 	/* If ctx2 is the parent of ctx1 */
3320 	if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3321 		return 1;
3322 
3323 	/*
3324 	 * If ctx1 and ctx2 have the same parent; we flatten the parent
3325 	 * hierarchy, see perf_event_init_context().
3326 	 */
3327 	if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3328 			ctx1->parent_gen == ctx2->parent_gen)
3329 		return 1;
3330 
3331 	/* Unmatched */
3332 	return 0;
3333 }
3334 
3335 static void __perf_event_sync_stat(struct perf_event *event,
3336 				     struct perf_event *next_event)
3337 {
3338 	u64 value;
3339 
3340 	if (!event->attr.inherit_stat)
3341 		return;
3342 
3343 	/*
3344 	 * Update the event value, we cannot use perf_event_read()
3345 	 * because we're in the middle of a context switch and have IRQs
3346 	 * disabled, which upsets smp_call_function_single(), however
3347 	 * we know the event must be on the current CPU, therefore we
3348 	 * don't need to use it.
3349 	 */
3350 	if (event->state == PERF_EVENT_STATE_ACTIVE)
3351 		event->pmu->read(event);
3352 
3353 	perf_event_update_time(event);
3354 
3355 	/*
3356 	 * In order to keep per-task stats reliable we need to flip the event
3357 	 * values when we flip the contexts.
3358 	 */
3359 	value = local64_read(&next_event->count);
3360 	value = local64_xchg(&event->count, value);
3361 	local64_set(&next_event->count, value);
3362 
3363 	swap(event->total_time_enabled, next_event->total_time_enabled);
3364 	swap(event->total_time_running, next_event->total_time_running);
3365 
3366 	/*
3367 	 * Since we swizzled the values, update the user visible data too.
3368 	 */
3369 	perf_event_update_userpage(event);
3370 	perf_event_update_userpage(next_event);
3371 }
3372 
3373 static void perf_event_sync_stat(struct perf_event_context *ctx,
3374 				   struct perf_event_context *next_ctx)
3375 {
3376 	struct perf_event *event, *next_event;
3377 
3378 	if (!ctx->nr_stat)
3379 		return;
3380 
3381 	update_context_time(ctx);
3382 
3383 	event = list_first_entry(&ctx->event_list,
3384 				   struct perf_event, event_entry);
3385 
3386 	next_event = list_first_entry(&next_ctx->event_list,
3387 					struct perf_event, event_entry);
3388 
3389 	while (&event->event_entry != &ctx->event_list &&
3390 	       &next_event->event_entry != &next_ctx->event_list) {
3391 
3392 		__perf_event_sync_stat(event, next_event);
3393 
3394 		event = list_next_entry(event, event_entry);
3395 		next_event = list_next_entry(next_event, event_entry);
3396 	}
3397 }
3398 
3399 #define double_list_for_each_entry(pos1, pos2, head1, head2, member)	\
3400 	for (pos1 = list_first_entry(head1, typeof(*pos1), member),	\
3401 	     pos2 = list_first_entry(head2, typeof(*pos2), member);	\
3402 	     !list_entry_is_head(pos1, head1, member) &&		\
3403 	     !list_entry_is_head(pos2, head2, member);			\
3404 	     pos1 = list_next_entry(pos1, member),			\
3405 	     pos2 = list_next_entry(pos2, member))
3406 
3407 static void perf_event_swap_task_ctx_data(struct perf_event_context *prev_ctx,
3408 					  struct perf_event_context *next_ctx)
3409 {
3410 	struct perf_event_pmu_context *prev_epc, *next_epc;
3411 
3412 	if (!prev_ctx->nr_task_data)
3413 		return;
3414 
3415 	double_list_for_each_entry(prev_epc, next_epc,
3416 				   &prev_ctx->pmu_ctx_list, &next_ctx->pmu_ctx_list,
3417 				   pmu_ctx_entry) {
3418 
3419 		if (WARN_ON_ONCE(prev_epc->pmu != next_epc->pmu))
3420 			continue;
3421 
3422 		/*
3423 		 * PMU specific parts of task perf context can require
3424 		 * additional synchronization. As an example of such
3425 		 * synchronization see implementation details of Intel
3426 		 * LBR call stack data profiling;
3427 		 */
3428 		if (prev_epc->pmu->swap_task_ctx)
3429 			prev_epc->pmu->swap_task_ctx(prev_epc, next_epc);
3430 		else
3431 			swap(prev_epc->task_ctx_data, next_epc->task_ctx_data);
3432 	}
3433 }
3434 
3435 static void perf_ctx_sched_task_cb(struct perf_event_context *ctx, bool sched_in)
3436 {
3437 	struct perf_event_pmu_context *pmu_ctx;
3438 	struct perf_cpu_pmu_context *cpc;
3439 
3440 	list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) {
3441 		cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context);
3442 
3443 		if (cpc->sched_cb_usage && pmu_ctx->pmu->sched_task)
3444 			pmu_ctx->pmu->sched_task(pmu_ctx, sched_in);
3445 	}
3446 }
3447 
3448 static void
3449 perf_event_context_sched_out(struct task_struct *task, struct task_struct *next)
3450 {
3451 	struct perf_event_context *ctx = task->perf_event_ctxp;
3452 	struct perf_event_context *next_ctx;
3453 	struct perf_event_context *parent, *next_parent;
3454 	int do_switch = 1;
3455 
3456 	if (likely(!ctx))
3457 		return;
3458 
3459 	rcu_read_lock();
3460 	next_ctx = rcu_dereference(next->perf_event_ctxp);
3461 	if (!next_ctx)
3462 		goto unlock;
3463 
3464 	parent = rcu_dereference(ctx->parent_ctx);
3465 	next_parent = rcu_dereference(next_ctx->parent_ctx);
3466 
3467 	/* If neither context have a parent context; they cannot be clones. */
3468 	if (!parent && !next_parent)
3469 		goto unlock;
3470 
3471 	if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3472 		/*
3473 		 * Looks like the two contexts are clones, so we might be
3474 		 * able to optimize the context switch.  We lock both
3475 		 * contexts and check that they are clones under the
3476 		 * lock (including re-checking that neither has been
3477 		 * uncloned in the meantime).  It doesn't matter which
3478 		 * order we take the locks because no other cpu could
3479 		 * be trying to lock both of these tasks.
3480 		 */
3481 		raw_spin_lock(&ctx->lock);
3482 		raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3483 		if (context_equiv(ctx, next_ctx)) {
3484 
3485 			perf_ctx_disable(ctx);
3486 
3487 			/* PMIs are disabled; ctx->nr_pending is stable. */
3488 			if (local_read(&ctx->nr_pending) ||
3489 			    local_read(&next_ctx->nr_pending)) {
3490 				/*
3491 				 * Must not swap out ctx when there's pending
3492 				 * events that rely on the ctx->task relation.
3493 				 */
3494 				raw_spin_unlock(&next_ctx->lock);
3495 				rcu_read_unlock();
3496 				goto inside_switch;
3497 			}
3498 
3499 			WRITE_ONCE(ctx->task, next);
3500 			WRITE_ONCE(next_ctx->task, task);
3501 
3502 			perf_ctx_sched_task_cb(ctx, false);
3503 			perf_event_swap_task_ctx_data(ctx, next_ctx);
3504 
3505 			perf_ctx_enable(ctx);
3506 
3507 			/*
3508 			 * RCU_INIT_POINTER here is safe because we've not
3509 			 * modified the ctx and the above modification of
3510 			 * ctx->task and ctx->task_ctx_data are immaterial
3511 			 * since those values are always verified under
3512 			 * ctx->lock which we're now holding.
3513 			 */
3514 			RCU_INIT_POINTER(task->perf_event_ctxp, next_ctx);
3515 			RCU_INIT_POINTER(next->perf_event_ctxp, ctx);
3516 
3517 			do_switch = 0;
3518 
3519 			perf_event_sync_stat(ctx, next_ctx);
3520 		}
3521 		raw_spin_unlock(&next_ctx->lock);
3522 		raw_spin_unlock(&ctx->lock);
3523 	}
3524 unlock:
3525 	rcu_read_unlock();
3526 
3527 	if (do_switch) {
3528 		raw_spin_lock(&ctx->lock);
3529 		perf_ctx_disable(ctx);
3530 
3531 inside_switch:
3532 		perf_ctx_sched_task_cb(ctx, false);
3533 		task_ctx_sched_out(ctx, EVENT_ALL);
3534 
3535 		perf_ctx_enable(ctx);
3536 		raw_spin_unlock(&ctx->lock);
3537 	}
3538 }
3539 
3540 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3541 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
3542 
3543 void perf_sched_cb_dec(struct pmu *pmu)
3544 {
3545 	struct perf_cpu_pmu_context *cpc = this_cpu_ptr(pmu->cpu_pmu_context);
3546 
3547 	this_cpu_dec(perf_sched_cb_usages);
3548 	barrier();
3549 
3550 	if (!--cpc->sched_cb_usage)
3551 		list_del(&cpc->sched_cb_entry);
3552 }
3553 
3554 
3555 void perf_sched_cb_inc(struct pmu *pmu)
3556 {
3557 	struct perf_cpu_pmu_context *cpc = this_cpu_ptr(pmu->cpu_pmu_context);
3558 
3559 	if (!cpc->sched_cb_usage++)
3560 		list_add(&cpc->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3561 
3562 	barrier();
3563 	this_cpu_inc(perf_sched_cb_usages);
3564 }
3565 
3566 /*
3567  * This function provides the context switch callback to the lower code
3568  * layer. It is invoked ONLY when the context switch callback is enabled.
3569  *
3570  * This callback is relevant even to per-cpu events; for example multi event
3571  * PEBS requires this to provide PID/TID information. This requires we flush
3572  * all queued PEBS records before we context switch to a new task.
3573  */
3574 static void __perf_pmu_sched_task(struct perf_cpu_pmu_context *cpc, bool sched_in)
3575 {
3576 	struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3577 	struct pmu *pmu;
3578 
3579 	pmu = cpc->epc.pmu;
3580 
3581 	/* software PMUs will not have sched_task */
3582 	if (WARN_ON_ONCE(!pmu->sched_task))
3583 		return;
3584 
3585 	perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3586 	perf_pmu_disable(pmu);
3587 
3588 	pmu->sched_task(cpc->task_epc, sched_in);
3589 
3590 	perf_pmu_enable(pmu);
3591 	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3592 }
3593 
3594 static void perf_pmu_sched_task(struct task_struct *prev,
3595 				struct task_struct *next,
3596 				bool sched_in)
3597 {
3598 	struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3599 	struct perf_cpu_pmu_context *cpc;
3600 
3601 	/* cpuctx->task_ctx will be handled in perf_event_context_sched_in/out */
3602 	if (prev == next || cpuctx->task_ctx)
3603 		return;
3604 
3605 	list_for_each_entry(cpc, this_cpu_ptr(&sched_cb_list), sched_cb_entry)
3606 		__perf_pmu_sched_task(cpc, sched_in);
3607 }
3608 
3609 static void perf_event_switch(struct task_struct *task,
3610 			      struct task_struct *next_prev, bool sched_in);
3611 
3612 /*
3613  * Called from scheduler to remove the events of the current task,
3614  * with interrupts disabled.
3615  *
3616  * We stop each event and update the event value in event->count.
3617  *
3618  * This does not protect us against NMI, but disable()
3619  * sets the disabled bit in the control field of event _before_
3620  * accessing the event control register. If a NMI hits, then it will
3621  * not restart the event.
3622  */
3623 void __perf_event_task_sched_out(struct task_struct *task,
3624 				 struct task_struct *next)
3625 {
3626 	if (__this_cpu_read(perf_sched_cb_usages))
3627 		perf_pmu_sched_task(task, next, false);
3628 
3629 	if (atomic_read(&nr_switch_events))
3630 		perf_event_switch(task, next, false);
3631 
3632 	perf_event_context_sched_out(task, next);
3633 
3634 	/*
3635 	 * if cgroup events exist on this CPU, then we need
3636 	 * to check if we have to switch out PMU state.
3637 	 * cgroup event are system-wide mode only
3638 	 */
3639 	perf_cgroup_switch(next);
3640 }
3641 
3642 static bool perf_less_group_idx(const void *l, const void *r)
3643 {
3644 	const struct perf_event *le = *(const struct perf_event **)l;
3645 	const struct perf_event *re = *(const struct perf_event **)r;
3646 
3647 	return le->group_index < re->group_index;
3648 }
3649 
3650 static void swap_ptr(void *l, void *r)
3651 {
3652 	void **lp = l, **rp = r;
3653 
3654 	swap(*lp, *rp);
3655 }
3656 
3657 static const struct min_heap_callbacks perf_min_heap = {
3658 	.elem_size = sizeof(struct perf_event *),
3659 	.less = perf_less_group_idx,
3660 	.swp = swap_ptr,
3661 };
3662 
3663 static void __heap_add(struct min_heap *heap, struct perf_event *event)
3664 {
3665 	struct perf_event **itrs = heap->data;
3666 
3667 	if (event) {
3668 		itrs[heap->nr] = event;
3669 		heap->nr++;
3670 	}
3671 }
3672 
3673 static void __link_epc(struct perf_event_pmu_context *pmu_ctx)
3674 {
3675 	struct perf_cpu_pmu_context *cpc;
3676 
3677 	if (!pmu_ctx->ctx->task)
3678 		return;
3679 
3680 	cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context);
3681 	WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx);
3682 	cpc->task_epc = pmu_ctx;
3683 }
3684 
3685 static noinline int visit_groups_merge(struct perf_event_context *ctx,
3686 				struct perf_event_groups *groups, int cpu,
3687 				struct pmu *pmu,
3688 				int (*func)(struct perf_event *, void *),
3689 				void *data)
3690 {
3691 #ifdef CONFIG_CGROUP_PERF
3692 	struct cgroup_subsys_state *css = NULL;
3693 #endif
3694 	struct perf_cpu_context *cpuctx = NULL;
3695 	/* Space for per CPU and/or any CPU event iterators. */
3696 	struct perf_event *itrs[2];
3697 	struct min_heap event_heap;
3698 	struct perf_event **evt;
3699 	int ret;
3700 
3701 	if (pmu->filter && pmu->filter(pmu, cpu))
3702 		return 0;
3703 
3704 	if (!ctx->task) {
3705 		cpuctx = this_cpu_ptr(&perf_cpu_context);
3706 		event_heap = (struct min_heap){
3707 			.data = cpuctx->heap,
3708 			.nr = 0,
3709 			.size = cpuctx->heap_size,
3710 		};
3711 
3712 		lockdep_assert_held(&cpuctx->ctx.lock);
3713 
3714 #ifdef CONFIG_CGROUP_PERF
3715 		if (cpuctx->cgrp)
3716 			css = &cpuctx->cgrp->css;
3717 #endif
3718 	} else {
3719 		event_heap = (struct min_heap){
3720 			.data = itrs,
3721 			.nr = 0,
3722 			.size = ARRAY_SIZE(itrs),
3723 		};
3724 		/* Events not within a CPU context may be on any CPU. */
3725 		__heap_add(&event_heap, perf_event_groups_first(groups, -1, pmu, NULL));
3726 	}
3727 	evt = event_heap.data;
3728 
3729 	__heap_add(&event_heap, perf_event_groups_first(groups, cpu, pmu, NULL));
3730 
3731 #ifdef CONFIG_CGROUP_PERF
3732 	for (; css; css = css->parent)
3733 		__heap_add(&event_heap, perf_event_groups_first(groups, cpu, pmu, css->cgroup));
3734 #endif
3735 
3736 	if (event_heap.nr) {
3737 		__link_epc((*evt)->pmu_ctx);
3738 		perf_assert_pmu_disabled((*evt)->pmu_ctx->pmu);
3739 	}
3740 
3741 	min_heapify_all(&event_heap, &perf_min_heap);
3742 
3743 	while (event_heap.nr) {
3744 		ret = func(*evt, data);
3745 		if (ret)
3746 			return ret;
3747 
3748 		*evt = perf_event_groups_next(*evt, pmu);
3749 		if (*evt)
3750 			min_heapify(&event_heap, 0, &perf_min_heap);
3751 		else
3752 			min_heap_pop(&event_heap, &perf_min_heap);
3753 	}
3754 
3755 	return 0;
3756 }
3757 
3758 /*
3759  * Because the userpage is strictly per-event (there is no concept of context,
3760  * so there cannot be a context indirection), every userpage must be updated
3761  * when context time starts :-(
3762  *
3763  * IOW, we must not miss EVENT_TIME edges.
3764  */
3765 static inline bool event_update_userpage(struct perf_event *event)
3766 {
3767 	if (likely(!atomic_read(&event->mmap_count)))
3768 		return false;
3769 
3770 	perf_event_update_time(event);
3771 	perf_event_update_userpage(event);
3772 
3773 	return true;
3774 }
3775 
3776 static inline void group_update_userpage(struct perf_event *group_event)
3777 {
3778 	struct perf_event *event;
3779 
3780 	if (!event_update_userpage(group_event))
3781 		return;
3782 
3783 	for_each_sibling_event(event, group_event)
3784 		event_update_userpage(event);
3785 }
3786 
3787 static int merge_sched_in(struct perf_event *event, void *data)
3788 {
3789 	struct perf_event_context *ctx = event->ctx;
3790 	int *can_add_hw = data;
3791 
3792 	if (event->state <= PERF_EVENT_STATE_OFF)
3793 		return 0;
3794 
3795 	if (!event_filter_match(event))
3796 		return 0;
3797 
3798 	if (group_can_go_on(event, *can_add_hw)) {
3799 		if (!group_sched_in(event, ctx))
3800 			list_add_tail(&event->active_list, get_event_list(event));
3801 	}
3802 
3803 	if (event->state == PERF_EVENT_STATE_INACTIVE) {
3804 		*can_add_hw = 0;
3805 		if (event->attr.pinned) {
3806 			perf_cgroup_event_disable(event, ctx);
3807 			perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3808 		} else {
3809 			struct perf_cpu_pmu_context *cpc;
3810 
3811 			event->pmu_ctx->rotate_necessary = 1;
3812 			cpc = this_cpu_ptr(event->pmu_ctx->pmu->cpu_pmu_context);
3813 			perf_mux_hrtimer_restart(cpc);
3814 			group_update_userpage(event);
3815 		}
3816 	}
3817 
3818 	return 0;
3819 }
3820 
3821 static void ctx_pinned_sched_in(struct perf_event_context *ctx, struct pmu *pmu)
3822 {
3823 	struct perf_event_pmu_context *pmu_ctx;
3824 	int can_add_hw = 1;
3825 
3826 	if (pmu) {
3827 		visit_groups_merge(ctx, &ctx->pinned_groups,
3828 				   smp_processor_id(), pmu,
3829 				   merge_sched_in, &can_add_hw);
3830 	} else {
3831 		list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) {
3832 			can_add_hw = 1;
3833 			visit_groups_merge(ctx, &ctx->pinned_groups,
3834 					   smp_processor_id(), pmu_ctx->pmu,
3835 					   merge_sched_in, &can_add_hw);
3836 		}
3837 	}
3838 }
3839 
3840 static void ctx_flexible_sched_in(struct perf_event_context *ctx, struct pmu *pmu)
3841 {
3842 	struct perf_event_pmu_context *pmu_ctx;
3843 	int can_add_hw = 1;
3844 
3845 	if (pmu) {
3846 		visit_groups_merge(ctx, &ctx->flexible_groups,
3847 				   smp_processor_id(), pmu,
3848 				   merge_sched_in, &can_add_hw);
3849 	} else {
3850 		list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) {
3851 			can_add_hw = 1;
3852 			visit_groups_merge(ctx, &ctx->flexible_groups,
3853 					   smp_processor_id(), pmu_ctx->pmu,
3854 					   merge_sched_in, &can_add_hw);
3855 		}
3856 	}
3857 }
3858 
3859 static void __pmu_ctx_sched_in(struct perf_event_context *ctx, struct pmu *pmu)
3860 {
3861 	ctx_flexible_sched_in(ctx, pmu);
3862 }
3863 
3864 static void
3865 ctx_sched_in(struct perf_event_context *ctx, enum event_type_t event_type)
3866 {
3867 	struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3868 	int is_active = ctx->is_active;
3869 
3870 	lockdep_assert_held(&ctx->lock);
3871 
3872 	if (likely(!ctx->nr_events))
3873 		return;
3874 
3875 	if (is_active ^ EVENT_TIME) {
3876 		/* start ctx time */
3877 		__update_context_time(ctx, false);
3878 		perf_cgroup_set_timestamp(cpuctx);
3879 		/*
3880 		 * CPU-release for the below ->is_active store,
3881 		 * see __load_acquire() in perf_event_time_now()
3882 		 */
3883 		barrier();
3884 	}
3885 
3886 	ctx->is_active |= (event_type | EVENT_TIME);
3887 	if (ctx->task) {
3888 		if (!is_active)
3889 			cpuctx->task_ctx = ctx;
3890 		else
3891 			WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3892 	}
3893 
3894 	is_active ^= ctx->is_active; /* changed bits */
3895 
3896 	/*
3897 	 * First go through the list and put on any pinned groups
3898 	 * in order to give them the best chance of going on.
3899 	 */
3900 	if (is_active & EVENT_PINNED)
3901 		ctx_pinned_sched_in(ctx, NULL);
3902 
3903 	/* Then walk through the lower prio flexible groups */
3904 	if (is_active & EVENT_FLEXIBLE)
3905 		ctx_flexible_sched_in(ctx, NULL);
3906 }
3907 
3908 static void perf_event_context_sched_in(struct task_struct *task)
3909 {
3910 	struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3911 	struct perf_event_context *ctx;
3912 
3913 	rcu_read_lock();
3914 	ctx = rcu_dereference(task->perf_event_ctxp);
3915 	if (!ctx)
3916 		goto rcu_unlock;
3917 
3918 	if (cpuctx->task_ctx == ctx) {
3919 		perf_ctx_lock(cpuctx, ctx);
3920 		perf_ctx_disable(ctx);
3921 
3922 		perf_ctx_sched_task_cb(ctx, true);
3923 
3924 		perf_ctx_enable(ctx);
3925 		perf_ctx_unlock(cpuctx, ctx);
3926 		goto rcu_unlock;
3927 	}
3928 
3929 	perf_ctx_lock(cpuctx, ctx);
3930 	/*
3931 	 * We must check ctx->nr_events while holding ctx->lock, such
3932 	 * that we serialize against perf_install_in_context().
3933 	 */
3934 	if (!ctx->nr_events)
3935 		goto unlock;
3936 
3937 	perf_ctx_disable(ctx);
3938 	/*
3939 	 * We want to keep the following priority order:
3940 	 * cpu pinned (that don't need to move), task pinned,
3941 	 * cpu flexible, task flexible.
3942 	 *
3943 	 * However, if task's ctx is not carrying any pinned
3944 	 * events, no need to flip the cpuctx's events around.
3945 	 */
3946 	if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree)) {
3947 		perf_ctx_disable(&cpuctx->ctx);
3948 		ctx_sched_out(&cpuctx->ctx, EVENT_FLEXIBLE);
3949 	}
3950 
3951 	perf_event_sched_in(cpuctx, ctx);
3952 
3953 	perf_ctx_sched_task_cb(cpuctx->task_ctx, true);
3954 
3955 	if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3956 		perf_ctx_enable(&cpuctx->ctx);
3957 
3958 	perf_ctx_enable(ctx);
3959 
3960 unlock:
3961 	perf_ctx_unlock(cpuctx, ctx);
3962 rcu_unlock:
3963 	rcu_read_unlock();
3964 }
3965 
3966 /*
3967  * Called from scheduler to add the events of the current task
3968  * with interrupts disabled.
3969  *
3970  * We restore the event value and then enable it.
3971  *
3972  * This does not protect us against NMI, but enable()
3973  * sets the enabled bit in the control field of event _before_
3974  * accessing the event control register. If a NMI hits, then it will
3975  * keep the event running.
3976  */
3977 void __perf_event_task_sched_in(struct task_struct *prev,
3978 				struct task_struct *task)
3979 {
3980 	perf_event_context_sched_in(task);
3981 
3982 	if (atomic_read(&nr_switch_events))
3983 		perf_event_switch(task, prev, true);
3984 
3985 	if (__this_cpu_read(perf_sched_cb_usages))
3986 		perf_pmu_sched_task(prev, task, true);
3987 }
3988 
3989 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3990 {
3991 	u64 frequency = event->attr.sample_freq;
3992 	u64 sec = NSEC_PER_SEC;
3993 	u64 divisor, dividend;
3994 
3995 	int count_fls, nsec_fls, frequency_fls, sec_fls;
3996 
3997 	count_fls = fls64(count);
3998 	nsec_fls = fls64(nsec);
3999 	frequency_fls = fls64(frequency);
4000 	sec_fls = 30;
4001 
4002 	/*
4003 	 * We got @count in @nsec, with a target of sample_freq HZ
4004 	 * the target period becomes:
4005 	 *
4006 	 *             @count * 10^9
4007 	 * period = -------------------
4008 	 *          @nsec * sample_freq
4009 	 *
4010 	 */
4011 
4012 	/*
4013 	 * Reduce accuracy by one bit such that @a and @b converge
4014 	 * to a similar magnitude.
4015 	 */
4016 #define REDUCE_FLS(a, b)		\
4017 do {					\
4018 	if (a##_fls > b##_fls) {	\
4019 		a >>= 1;		\
4020 		a##_fls--;		\
4021 	} else {			\
4022 		b >>= 1;		\
4023 		b##_fls--;		\
4024 	}				\
4025 } while (0)
4026 
4027 	/*
4028 	 * Reduce accuracy until either term fits in a u64, then proceed with
4029 	 * the other, so that finally we can do a u64/u64 division.
4030 	 */
4031 	while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
4032 		REDUCE_FLS(nsec, frequency);
4033 		REDUCE_FLS(sec, count);
4034 	}
4035 
4036 	if (count_fls + sec_fls > 64) {
4037 		divisor = nsec * frequency;
4038 
4039 		while (count_fls + sec_fls > 64) {
4040 			REDUCE_FLS(count, sec);
4041 			divisor >>= 1;
4042 		}
4043 
4044 		dividend = count * sec;
4045 	} else {
4046 		dividend = count * sec;
4047 
4048 		while (nsec_fls + frequency_fls > 64) {
4049 			REDUCE_FLS(nsec, frequency);
4050 			dividend >>= 1;
4051 		}
4052 
4053 		divisor = nsec * frequency;
4054 	}
4055 
4056 	if (!divisor)
4057 		return dividend;
4058 
4059 	return div64_u64(dividend, divisor);
4060 }
4061 
4062 static DEFINE_PER_CPU(int, perf_throttled_count);
4063 static DEFINE_PER_CPU(u64, perf_throttled_seq);
4064 
4065 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
4066 {
4067 	struct hw_perf_event *hwc = &event->hw;
4068 	s64 period, sample_period;
4069 	s64 delta;
4070 
4071 	period = perf_calculate_period(event, nsec, count);
4072 
4073 	delta = (s64)(period - hwc->sample_period);
4074 	delta = (delta + 7) / 8; /* low pass filter */
4075 
4076 	sample_period = hwc->sample_period + delta;
4077 
4078 	if (!sample_period)
4079 		sample_period = 1;
4080 
4081 	hwc->sample_period = sample_period;
4082 
4083 	if (local64_read(&hwc->period_left) > 8*sample_period) {
4084 		if (disable)
4085 			event->pmu->stop(event, PERF_EF_UPDATE);
4086 
4087 		local64_set(&hwc->period_left, 0);
4088 
4089 		if (disable)
4090 			event->pmu->start(event, PERF_EF_RELOAD);
4091 	}
4092 }
4093 
4094 /*
4095  * combine freq adjustment with unthrottling to avoid two passes over the
4096  * events. At the same time, make sure, having freq events does not change
4097  * the rate of unthrottling as that would introduce bias.
4098  */
4099 static void
4100 perf_adjust_freq_unthr_context(struct perf_event_context *ctx, bool unthrottle)
4101 {
4102 	struct perf_event *event;
4103 	struct hw_perf_event *hwc;
4104 	u64 now, period = TICK_NSEC;
4105 	s64 delta;
4106 
4107 	/*
4108 	 * only need to iterate over all events iff:
4109 	 * - context have events in frequency mode (needs freq adjust)
4110 	 * - there are events to unthrottle on this cpu
4111 	 */
4112 	if (!(ctx->nr_freq || unthrottle))
4113 		return;
4114 
4115 	raw_spin_lock(&ctx->lock);
4116 
4117 	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4118 		if (event->state != PERF_EVENT_STATE_ACTIVE)
4119 			continue;
4120 
4121 		// XXX use visit thingy to avoid the -1,cpu match
4122 		if (!event_filter_match(event))
4123 			continue;
4124 
4125 		perf_pmu_disable(event->pmu);
4126 
4127 		hwc = &event->hw;
4128 
4129 		if (hwc->interrupts == MAX_INTERRUPTS) {
4130 			hwc->interrupts = 0;
4131 			perf_log_throttle(event, 1);
4132 			event->pmu->start(event, 0);
4133 		}
4134 
4135 		if (!event->attr.freq || !event->attr.sample_freq)
4136 			goto next;
4137 
4138 		/*
4139 		 * stop the event and update event->count
4140 		 */
4141 		event->pmu->stop(event, PERF_EF_UPDATE);
4142 
4143 		now = local64_read(&event->count);
4144 		delta = now - hwc->freq_count_stamp;
4145 		hwc->freq_count_stamp = now;
4146 
4147 		/*
4148 		 * restart the event
4149 		 * reload only if value has changed
4150 		 * we have stopped the event so tell that
4151 		 * to perf_adjust_period() to avoid stopping it
4152 		 * twice.
4153 		 */
4154 		if (delta > 0)
4155 			perf_adjust_period(event, period, delta, false);
4156 
4157 		event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
4158 	next:
4159 		perf_pmu_enable(event->pmu);
4160 	}
4161 
4162 	raw_spin_unlock(&ctx->lock);
4163 }
4164 
4165 /*
4166  * Move @event to the tail of the @ctx's elegible events.
4167  */
4168 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
4169 {
4170 	/*
4171 	 * Rotate the first entry last of non-pinned groups. Rotation might be
4172 	 * disabled by the inheritance code.
4173 	 */
4174 	if (ctx->rotate_disable)
4175 		return;
4176 
4177 	perf_event_groups_delete(&ctx->flexible_groups, event);
4178 	perf_event_groups_insert(&ctx->flexible_groups, event);
4179 }
4180 
4181 /* pick an event from the flexible_groups to rotate */
4182 static inline struct perf_event *
4183 ctx_event_to_rotate(struct perf_event_pmu_context *pmu_ctx)
4184 {
4185 	struct perf_event *event;
4186 	struct rb_node *node;
4187 	struct rb_root *tree;
4188 	struct __group_key key = {
4189 		.pmu = pmu_ctx->pmu,
4190 	};
4191 
4192 	/* pick the first active flexible event */
4193 	event = list_first_entry_or_null(&pmu_ctx->flexible_active,
4194 					 struct perf_event, active_list);
4195 	if (event)
4196 		goto out;
4197 
4198 	/* if no active flexible event, pick the first event */
4199 	tree = &pmu_ctx->ctx->flexible_groups.tree;
4200 
4201 	if (!pmu_ctx->ctx->task) {
4202 		key.cpu = smp_processor_id();
4203 
4204 		node = rb_find_first(&key, tree, __group_cmp_ignore_cgroup);
4205 		if (node)
4206 			event = __node_2_pe(node);
4207 		goto out;
4208 	}
4209 
4210 	key.cpu = -1;
4211 	node = rb_find_first(&key, tree, __group_cmp_ignore_cgroup);
4212 	if (node) {
4213 		event = __node_2_pe(node);
4214 		goto out;
4215 	}
4216 
4217 	key.cpu = smp_processor_id();
4218 	node = rb_find_first(&key, tree, __group_cmp_ignore_cgroup);
4219 	if (node)
4220 		event = __node_2_pe(node);
4221 
4222 out:
4223 	/*
4224 	 * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in()
4225 	 * finds there are unschedulable events, it will set it again.
4226 	 */
4227 	pmu_ctx->rotate_necessary = 0;
4228 
4229 	return event;
4230 }
4231 
4232 static bool perf_rotate_context(struct perf_cpu_pmu_context *cpc)
4233 {
4234 	struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
4235 	struct perf_event_pmu_context *cpu_epc, *task_epc = NULL;
4236 	struct perf_event *cpu_event = NULL, *task_event = NULL;
4237 	int cpu_rotate, task_rotate;
4238 	struct pmu *pmu;
4239 
4240 	/*
4241 	 * Since we run this from IRQ context, nobody can install new
4242 	 * events, thus the event count values are stable.
4243 	 */
4244 
4245 	cpu_epc = &cpc->epc;
4246 	pmu = cpu_epc->pmu;
4247 	task_epc = cpc->task_epc;
4248 
4249 	cpu_rotate = cpu_epc->rotate_necessary;
4250 	task_rotate = task_epc ? task_epc->rotate_necessary : 0;
4251 
4252 	if (!(cpu_rotate || task_rotate))
4253 		return false;
4254 
4255 	perf_ctx_lock(cpuctx, cpuctx->task_ctx);
4256 	perf_pmu_disable(pmu);
4257 
4258 	if (task_rotate)
4259 		task_event = ctx_event_to_rotate(task_epc);
4260 	if (cpu_rotate)
4261 		cpu_event = ctx_event_to_rotate(cpu_epc);
4262 
4263 	/*
4264 	 * As per the order given at ctx_resched() first 'pop' task flexible
4265 	 * and then, if needed CPU flexible.
4266 	 */
4267 	if (task_event || (task_epc && cpu_event)) {
4268 		update_context_time(task_epc->ctx);
4269 		__pmu_ctx_sched_out(task_epc, EVENT_FLEXIBLE);
4270 	}
4271 
4272 	if (cpu_event) {
4273 		update_context_time(&cpuctx->ctx);
4274 		__pmu_ctx_sched_out(cpu_epc, EVENT_FLEXIBLE);
4275 		rotate_ctx(&cpuctx->ctx, cpu_event);
4276 		__pmu_ctx_sched_in(&cpuctx->ctx, pmu);
4277 	}
4278 
4279 	if (task_event)
4280 		rotate_ctx(task_epc->ctx, task_event);
4281 
4282 	if (task_event || (task_epc && cpu_event))
4283 		__pmu_ctx_sched_in(task_epc->ctx, pmu);
4284 
4285 	perf_pmu_enable(pmu);
4286 	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
4287 
4288 	return true;
4289 }
4290 
4291 void perf_event_task_tick(void)
4292 {
4293 	struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
4294 	struct perf_event_context *ctx;
4295 	int throttled;
4296 
4297 	lockdep_assert_irqs_disabled();
4298 
4299 	__this_cpu_inc(perf_throttled_seq);
4300 	throttled = __this_cpu_xchg(perf_throttled_count, 0);
4301 	tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
4302 
4303 	perf_adjust_freq_unthr_context(&cpuctx->ctx, !!throttled);
4304 
4305 	rcu_read_lock();
4306 	ctx = rcu_dereference(current->perf_event_ctxp);
4307 	if (ctx)
4308 		perf_adjust_freq_unthr_context(ctx, !!throttled);
4309 	rcu_read_unlock();
4310 }
4311 
4312 static int event_enable_on_exec(struct perf_event *event,
4313 				struct perf_event_context *ctx)
4314 {
4315 	if (!event->attr.enable_on_exec)
4316 		return 0;
4317 
4318 	event->attr.enable_on_exec = 0;
4319 	if (event->state >= PERF_EVENT_STATE_INACTIVE)
4320 		return 0;
4321 
4322 	perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
4323 
4324 	return 1;
4325 }
4326 
4327 /*
4328  * Enable all of a task's events that have been marked enable-on-exec.
4329  * This expects task == current.
4330  */
4331 static void perf_event_enable_on_exec(struct perf_event_context *ctx)
4332 {
4333 	struct perf_event_context *clone_ctx = NULL;
4334 	enum event_type_t event_type = 0;
4335 	struct perf_cpu_context *cpuctx;
4336 	struct perf_event *event;
4337 	unsigned long flags;
4338 	int enabled = 0;
4339 
4340 	local_irq_save(flags);
4341 	if (WARN_ON_ONCE(current->perf_event_ctxp != ctx))
4342 		goto out;
4343 
4344 	if (!ctx->nr_events)
4345 		goto out;
4346 
4347 	cpuctx = this_cpu_ptr(&perf_cpu_context);
4348 	perf_ctx_lock(cpuctx, ctx);
4349 	ctx_sched_out(ctx, EVENT_TIME);
4350 
4351 	list_for_each_entry(event, &ctx->event_list, event_entry) {
4352 		enabled |= event_enable_on_exec(event, ctx);
4353 		event_type |= get_event_type(event);
4354 	}
4355 
4356 	/*
4357 	 * Unclone and reschedule this context if we enabled any event.
4358 	 */
4359 	if (enabled) {
4360 		clone_ctx = unclone_ctx(ctx);
4361 		ctx_resched(cpuctx, ctx, event_type);
4362 	} else {
4363 		ctx_sched_in(ctx, EVENT_TIME);
4364 	}
4365 	perf_ctx_unlock(cpuctx, ctx);
4366 
4367 out:
4368 	local_irq_restore(flags);
4369 
4370 	if (clone_ctx)
4371 		put_ctx(clone_ctx);
4372 }
4373 
4374 static void perf_remove_from_owner(struct perf_event *event);
4375 static void perf_event_exit_event(struct perf_event *event,
4376 				  struct perf_event_context *ctx);
4377 
4378 /*
4379  * Removes all events from the current task that have been marked
4380  * remove-on-exec, and feeds their values back to parent events.
4381  */
4382 static void perf_event_remove_on_exec(struct perf_event_context *ctx)
4383 {
4384 	struct perf_event_context *clone_ctx = NULL;
4385 	struct perf_event *event, *next;
4386 	unsigned long flags;
4387 	bool modified = false;
4388 
4389 	mutex_lock(&ctx->mutex);
4390 
4391 	if (WARN_ON_ONCE(ctx->task != current))
4392 		goto unlock;
4393 
4394 	list_for_each_entry_safe(event, next, &ctx->event_list, event_entry) {
4395 		if (!event->attr.remove_on_exec)
4396 			continue;
4397 
4398 		if (!is_kernel_event(event))
4399 			perf_remove_from_owner(event);
4400 
4401 		modified = true;
4402 
4403 		perf_event_exit_event(event, ctx);
4404 	}
4405 
4406 	raw_spin_lock_irqsave(&ctx->lock, flags);
4407 	if (modified)
4408 		clone_ctx = unclone_ctx(ctx);
4409 	raw_spin_unlock_irqrestore(&ctx->lock, flags);
4410 
4411 unlock:
4412 	mutex_unlock(&ctx->mutex);
4413 
4414 	if (clone_ctx)
4415 		put_ctx(clone_ctx);
4416 }
4417 
4418 struct perf_read_data {
4419 	struct perf_event *event;
4420 	bool group;
4421 	int ret;
4422 };
4423 
4424 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
4425 {
4426 	u16 local_pkg, event_pkg;
4427 
4428 	if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
4429 		int local_cpu = smp_processor_id();
4430 
4431 		event_pkg = topology_physical_package_id(event_cpu);
4432 		local_pkg = topology_physical_package_id(local_cpu);
4433 
4434 		if (event_pkg == local_pkg)
4435 			return local_cpu;
4436 	}
4437 
4438 	return event_cpu;
4439 }
4440 
4441 /*
4442  * Cross CPU call to read the hardware event
4443  */
4444 static void __perf_event_read(void *info)
4445 {
4446 	struct perf_read_data *data = info;
4447 	struct perf_event *sub, *event = data->event;
4448 	struct perf_event_context *ctx = event->ctx;
4449 	struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
4450 	struct pmu *pmu = event->pmu;
4451 
4452 	/*
4453 	 * If this is a task context, we need to check whether it is
4454 	 * the current task context of this cpu.  If not it has been
4455 	 * scheduled out before the smp call arrived.  In that case
4456 	 * event->count would have been updated to a recent sample
4457 	 * when the event was scheduled out.
4458 	 */
4459 	if (ctx->task && cpuctx->task_ctx != ctx)
4460 		return;
4461 
4462 	raw_spin_lock(&ctx->lock);
4463 	if (ctx->is_active & EVENT_TIME) {
4464 		update_context_time(ctx);
4465 		update_cgrp_time_from_event(event);
4466 	}
4467 
4468 	perf_event_update_time(event);
4469 	if (data->group)
4470 		perf_event_update_sibling_time(event);
4471 
4472 	if (event->state != PERF_EVENT_STATE_ACTIVE)
4473 		goto unlock;
4474 
4475 	if (!data->group) {
4476 		pmu->read(event);
4477 		data->ret = 0;
4478 		goto unlock;
4479 	}
4480 
4481 	pmu->start_txn(pmu, PERF_PMU_TXN_READ);
4482 
4483 	pmu->read(event);
4484 
4485 	for_each_sibling_event(sub, event) {
4486 		if (sub->state == PERF_EVENT_STATE_ACTIVE) {
4487 			/*
4488 			 * Use sibling's PMU rather than @event's since
4489 			 * sibling could be on different (eg: software) PMU.
4490 			 */
4491 			sub->pmu->read(sub);
4492 		}
4493 	}
4494 
4495 	data->ret = pmu->commit_txn(pmu);
4496 
4497 unlock:
4498 	raw_spin_unlock(&ctx->lock);
4499 }
4500 
4501 static inline u64 perf_event_count(struct perf_event *event)
4502 {
4503 	return local64_read(&event->count) + atomic64_read(&event->child_count);
4504 }
4505 
4506 static void calc_timer_values(struct perf_event *event,
4507 				u64 *now,
4508 				u64 *enabled,
4509 				u64 *running)
4510 {
4511 	u64 ctx_time;
4512 
4513 	*now = perf_clock();
4514 	ctx_time = perf_event_time_now(event, *now);
4515 	__perf_update_times(event, ctx_time, enabled, running);
4516 }
4517 
4518 /*
4519  * NMI-safe method to read a local event, that is an event that
4520  * is:
4521  *   - either for the current task, or for this CPU
4522  *   - does not have inherit set, for inherited task events
4523  *     will not be local and we cannot read them atomically
4524  *   - must not have a pmu::count method
4525  */
4526 int perf_event_read_local(struct perf_event *event, u64 *value,
4527 			  u64 *enabled, u64 *running)
4528 {
4529 	unsigned long flags;
4530 	int ret = 0;
4531 
4532 	/*
4533 	 * Disabling interrupts avoids all counter scheduling (context
4534 	 * switches, timer based rotation and IPIs).
4535 	 */
4536 	local_irq_save(flags);
4537 
4538 	/*
4539 	 * It must not be an event with inherit set, we cannot read
4540 	 * all child counters from atomic context.
4541 	 */
4542 	if (event->attr.inherit) {
4543 		ret = -EOPNOTSUPP;
4544 		goto out;
4545 	}
4546 
4547 	/* If this is a per-task event, it must be for current */
4548 	if ((event->attach_state & PERF_ATTACH_TASK) &&
4549 	    event->hw.target != current) {
4550 		ret = -EINVAL;
4551 		goto out;
4552 	}
4553 
4554 	/* If this is a per-CPU event, it must be for this CPU */
4555 	if (!(event->attach_state & PERF_ATTACH_TASK) &&
4556 	    event->cpu != smp_processor_id()) {
4557 		ret = -EINVAL;
4558 		goto out;
4559 	}
4560 
4561 	/* If this is a pinned event it must be running on this CPU */
4562 	if (event->attr.pinned && event->oncpu != smp_processor_id()) {
4563 		ret = -EBUSY;
4564 		goto out;
4565 	}
4566 
4567 	/*
4568 	 * If the event is currently on this CPU, its either a per-task event,
4569 	 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4570 	 * oncpu == -1).
4571 	 */
4572 	if (event->oncpu == smp_processor_id())
4573 		event->pmu->read(event);
4574 
4575 	*value = local64_read(&event->count);
4576 	if (enabled || running) {
4577 		u64 __enabled, __running, __now;
4578 
4579 		calc_timer_values(event, &__now, &__enabled, &__running);
4580 		if (enabled)
4581 			*enabled = __enabled;
4582 		if (running)
4583 			*running = __running;
4584 	}
4585 out:
4586 	local_irq_restore(flags);
4587 
4588 	return ret;
4589 }
4590 
4591 static int perf_event_read(struct perf_event *event, bool group)
4592 {
4593 	enum perf_event_state state = READ_ONCE(event->state);
4594 	int event_cpu, ret = 0;
4595 
4596 	/*
4597 	 * If event is enabled and currently active on a CPU, update the
4598 	 * value in the event structure:
4599 	 */
4600 again:
4601 	if (state == PERF_EVENT_STATE_ACTIVE) {
4602 		struct perf_read_data data;
4603 
4604 		/*
4605 		 * Orders the ->state and ->oncpu loads such that if we see
4606 		 * ACTIVE we must also see the right ->oncpu.
4607 		 *
4608 		 * Matches the smp_wmb() from event_sched_in().
4609 		 */
4610 		smp_rmb();
4611 
4612 		event_cpu = READ_ONCE(event->oncpu);
4613 		if ((unsigned)event_cpu >= nr_cpu_ids)
4614 			return 0;
4615 
4616 		data = (struct perf_read_data){
4617 			.event = event,
4618 			.group = group,
4619 			.ret = 0,
4620 		};
4621 
4622 		preempt_disable();
4623 		event_cpu = __perf_event_read_cpu(event, event_cpu);
4624 
4625 		/*
4626 		 * Purposely ignore the smp_call_function_single() return
4627 		 * value.
4628 		 *
4629 		 * If event_cpu isn't a valid CPU it means the event got
4630 		 * scheduled out and that will have updated the event count.
4631 		 *
4632 		 * Therefore, either way, we'll have an up-to-date event count
4633 		 * after this.
4634 		 */
4635 		(void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4636 		preempt_enable();
4637 		ret = data.ret;
4638 
4639 	} else if (state == PERF_EVENT_STATE_INACTIVE) {
4640 		struct perf_event_context *ctx = event->ctx;
4641 		unsigned long flags;
4642 
4643 		raw_spin_lock_irqsave(&ctx->lock, flags);
4644 		state = event->state;
4645 		if (state != PERF_EVENT_STATE_INACTIVE) {
4646 			raw_spin_unlock_irqrestore(&ctx->lock, flags);
4647 			goto again;
4648 		}
4649 
4650 		/*
4651 		 * May read while context is not active (e.g., thread is
4652 		 * blocked), in that case we cannot update context time
4653 		 */
4654 		if (ctx->is_active & EVENT_TIME) {
4655 			update_context_time(ctx);
4656 			update_cgrp_time_from_event(event);
4657 		}
4658 
4659 		perf_event_update_time(event);
4660 		if (group)
4661 			perf_event_update_sibling_time(event);
4662 		raw_spin_unlock_irqrestore(&ctx->lock, flags);
4663 	}
4664 
4665 	return ret;
4666 }
4667 
4668 /*
4669  * Initialize the perf_event context in a task_struct:
4670  */
4671 static void __perf_event_init_context(struct perf_event_context *ctx)
4672 {
4673 	raw_spin_lock_init(&ctx->lock);
4674 	mutex_init(&ctx->mutex);
4675 	INIT_LIST_HEAD(&ctx->pmu_ctx_list);
4676 	perf_event_groups_init(&ctx->pinned_groups);
4677 	perf_event_groups_init(&ctx->flexible_groups);
4678 	INIT_LIST_HEAD(&ctx->event_list);
4679 	refcount_set(&ctx->refcount, 1);
4680 }
4681 
4682 static void
4683 __perf_init_event_pmu_context(struct perf_event_pmu_context *epc, struct pmu *pmu)
4684 {
4685 	epc->pmu = pmu;
4686 	INIT_LIST_HEAD(&epc->pmu_ctx_entry);
4687 	INIT_LIST_HEAD(&epc->pinned_active);
4688 	INIT_LIST_HEAD(&epc->flexible_active);
4689 	atomic_set(&epc->refcount, 1);
4690 }
4691 
4692 static struct perf_event_context *
4693 alloc_perf_context(struct task_struct *task)
4694 {
4695 	struct perf_event_context *ctx;
4696 
4697 	ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4698 	if (!ctx)
4699 		return NULL;
4700 
4701 	__perf_event_init_context(ctx);
4702 	if (task)
4703 		ctx->task = get_task_struct(task);
4704 
4705 	return ctx;
4706 }
4707 
4708 static struct task_struct *
4709 find_lively_task_by_vpid(pid_t vpid)
4710 {
4711 	struct task_struct *task;
4712 
4713 	rcu_read_lock();
4714 	if (!vpid)
4715 		task = current;
4716 	else
4717 		task = find_task_by_vpid(vpid);
4718 	if (task)
4719 		get_task_struct(task);
4720 	rcu_read_unlock();
4721 
4722 	if (!task)
4723 		return ERR_PTR(-ESRCH);
4724 
4725 	return task;
4726 }
4727 
4728 /*
4729  * Returns a matching context with refcount and pincount.
4730  */
4731 static struct perf_event_context *
4732 find_get_context(struct task_struct *task, struct perf_event *event)
4733 {
4734 	struct perf_event_context *ctx, *clone_ctx = NULL;
4735 	struct perf_cpu_context *cpuctx;
4736 	unsigned long flags;
4737 	int err;
4738 
4739 	if (!task) {
4740 		/* Must be root to operate on a CPU event: */
4741 		err = perf_allow_cpu(&event->attr);
4742 		if (err)
4743 			return ERR_PTR(err);
4744 
4745 		cpuctx = per_cpu_ptr(&perf_cpu_context, event->cpu);
4746 		ctx = &cpuctx->ctx;
4747 		get_ctx(ctx);
4748 		raw_spin_lock_irqsave(&ctx->lock, flags);
4749 		++ctx->pin_count;
4750 		raw_spin_unlock_irqrestore(&ctx->lock, flags);
4751 
4752 		return ctx;
4753 	}
4754 
4755 	err = -EINVAL;
4756 retry:
4757 	ctx = perf_lock_task_context(task, &flags);
4758 	if (ctx) {
4759 		clone_ctx = unclone_ctx(ctx);
4760 		++ctx->pin_count;
4761 
4762 		raw_spin_unlock_irqrestore(&ctx->lock, flags);
4763 
4764 		if (clone_ctx)
4765 			put_ctx(clone_ctx);
4766 	} else {
4767 		ctx = alloc_perf_context(task);
4768 		err = -ENOMEM;
4769 		if (!ctx)
4770 			goto errout;
4771 
4772 		err = 0;
4773 		mutex_lock(&task->perf_event_mutex);
4774 		/*
4775 		 * If it has already passed perf_event_exit_task().
4776 		 * we must see PF_EXITING, it takes this mutex too.
4777 		 */
4778 		if (task->flags & PF_EXITING)
4779 			err = -ESRCH;
4780 		else if (task->perf_event_ctxp)
4781 			err = -EAGAIN;
4782 		else {
4783 			get_ctx(ctx);
4784 			++ctx->pin_count;
4785 			rcu_assign_pointer(task->perf_event_ctxp, ctx);
4786 		}
4787 		mutex_unlock(&task->perf_event_mutex);
4788 
4789 		if (unlikely(err)) {
4790 			put_ctx(ctx);
4791 
4792 			if (err == -EAGAIN)
4793 				goto retry;
4794 			goto errout;
4795 		}
4796 	}
4797 
4798 	return ctx;
4799 
4800 errout:
4801 	return ERR_PTR(err);
4802 }
4803 
4804 static struct perf_event_pmu_context *
4805 find_get_pmu_context(struct pmu *pmu, struct perf_event_context *ctx,
4806 		     struct perf_event *event)
4807 {
4808 	struct perf_event_pmu_context *new = NULL, *epc;
4809 	void *task_ctx_data = NULL;
4810 
4811 	if (!ctx->task) {
4812 		struct perf_cpu_pmu_context *cpc;
4813 
4814 		cpc = per_cpu_ptr(pmu->cpu_pmu_context, event->cpu);
4815 		epc = &cpc->epc;
4816 
4817 		if (!epc->ctx) {
4818 			atomic_set(&epc->refcount, 1);
4819 			epc->embedded = 1;
4820 			raw_spin_lock_irq(&ctx->lock);
4821 			list_add(&epc->pmu_ctx_entry, &ctx->pmu_ctx_list);
4822 			epc->ctx = ctx;
4823 			raw_spin_unlock_irq(&ctx->lock);
4824 		} else {
4825 			WARN_ON_ONCE(epc->ctx != ctx);
4826 			atomic_inc(&epc->refcount);
4827 		}
4828 
4829 		return epc;
4830 	}
4831 
4832 	new = kzalloc(sizeof(*epc), GFP_KERNEL);
4833 	if (!new)
4834 		return ERR_PTR(-ENOMEM);
4835 
4836 	if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4837 		task_ctx_data = alloc_task_ctx_data(pmu);
4838 		if (!task_ctx_data) {
4839 			kfree(new);
4840 			return ERR_PTR(-ENOMEM);
4841 		}
4842 	}
4843 
4844 	__perf_init_event_pmu_context(new, pmu);
4845 
4846 	/*
4847 	 * XXX
4848 	 *
4849 	 * lockdep_assert_held(&ctx->mutex);
4850 	 *
4851 	 * can't because perf_event_init_task() doesn't actually hold the
4852 	 * child_ctx->mutex.
4853 	 */
4854 
4855 	raw_spin_lock_irq(&ctx->lock);
4856 	list_for_each_entry(epc, &ctx->pmu_ctx_list, pmu_ctx_entry) {
4857 		if (epc->pmu == pmu) {
4858 			WARN_ON_ONCE(epc->ctx != ctx);
4859 			atomic_inc(&epc->refcount);
4860 			goto found_epc;
4861 		}
4862 	}
4863 
4864 	epc = new;
4865 	new = NULL;
4866 
4867 	list_add(&epc->pmu_ctx_entry, &ctx->pmu_ctx_list);
4868 	epc->ctx = ctx;
4869 
4870 found_epc:
4871 	if (task_ctx_data && !epc->task_ctx_data) {
4872 		epc->task_ctx_data = task_ctx_data;
4873 		task_ctx_data = NULL;
4874 		ctx->nr_task_data++;
4875 	}
4876 	raw_spin_unlock_irq(&ctx->lock);
4877 
4878 	free_task_ctx_data(pmu, task_ctx_data);
4879 	kfree(new);
4880 
4881 	return epc;
4882 }
4883 
4884 static void get_pmu_ctx(struct perf_event_pmu_context *epc)
4885 {
4886 	WARN_ON_ONCE(!atomic_inc_not_zero(&epc->refcount));
4887 }
4888 
4889 static void free_epc_rcu(struct rcu_head *head)
4890 {
4891 	struct perf_event_pmu_context *epc = container_of(head, typeof(*epc), rcu_head);
4892 
4893 	kfree(epc->task_ctx_data);
4894 	kfree(epc);
4895 }
4896 
4897 static void put_pmu_ctx(struct perf_event_pmu_context *epc)
4898 {
4899 	unsigned long flags;
4900 
4901 	if (!atomic_dec_and_test(&epc->refcount))
4902 		return;
4903 
4904 	if (epc->ctx) {
4905 		struct perf_event_context *ctx = epc->ctx;
4906 
4907 		/*
4908 		 * XXX
4909 		 *
4910 		 * lockdep_assert_held(&ctx->mutex);
4911 		 *
4912 		 * can't because of the call-site in _free_event()/put_event()
4913 		 * which isn't always called under ctx->mutex.
4914 		 */
4915 
4916 		WARN_ON_ONCE(list_empty(&epc->pmu_ctx_entry));
4917 		raw_spin_lock_irqsave(&ctx->lock, flags);
4918 		list_del_init(&epc->pmu_ctx_entry);
4919 		epc->ctx = NULL;
4920 		raw_spin_unlock_irqrestore(&ctx->lock, flags);
4921 	}
4922 
4923 	WARN_ON_ONCE(!list_empty(&epc->pinned_active));
4924 	WARN_ON_ONCE(!list_empty(&epc->flexible_active));
4925 
4926 	if (epc->embedded)
4927 		return;
4928 
4929 	call_rcu(&epc->rcu_head, free_epc_rcu);
4930 }
4931 
4932 static void perf_event_free_filter(struct perf_event *event);
4933 
4934 static void free_event_rcu(struct rcu_head *head)
4935 {
4936 	struct perf_event *event = container_of(head, typeof(*event), rcu_head);
4937 
4938 	if (event->ns)
4939 		put_pid_ns(event->ns);
4940 	perf_event_free_filter(event);
4941 	kmem_cache_free(perf_event_cache, event);
4942 }
4943 
4944 static void ring_buffer_attach(struct perf_event *event,
4945 			       struct perf_buffer *rb);
4946 
4947 static void detach_sb_event(struct perf_event *event)
4948 {
4949 	struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4950 
4951 	raw_spin_lock(&pel->lock);
4952 	list_del_rcu(&event->sb_list);
4953 	raw_spin_unlock(&pel->lock);
4954 }
4955 
4956 static bool is_sb_event(struct perf_event *event)
4957 {
4958 	struct perf_event_attr *attr = &event->attr;
4959 
4960 	if (event->parent)
4961 		return false;
4962 
4963 	if (event->attach_state & PERF_ATTACH_TASK)
4964 		return false;
4965 
4966 	if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4967 	    attr->comm || attr->comm_exec ||
4968 	    attr->task || attr->ksymbol ||
4969 	    attr->context_switch || attr->text_poke ||
4970 	    attr->bpf_event)
4971 		return true;
4972 	return false;
4973 }
4974 
4975 static void unaccount_pmu_sb_event(struct perf_event *event)
4976 {
4977 	if (is_sb_event(event))
4978 		detach_sb_event(event);
4979 }
4980 
4981 #ifdef CONFIG_NO_HZ_FULL
4982 static DEFINE_SPINLOCK(nr_freq_lock);
4983 #endif
4984 
4985 static void unaccount_freq_event_nohz(void)
4986 {
4987 #ifdef CONFIG_NO_HZ_FULL
4988 	spin_lock(&nr_freq_lock);
4989 	if (atomic_dec_and_test(&nr_freq_events))
4990 		tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4991 	spin_unlock(&nr_freq_lock);
4992 #endif
4993 }
4994 
4995 static void unaccount_freq_event(void)
4996 {
4997 	if (tick_nohz_full_enabled())
4998 		unaccount_freq_event_nohz();
4999 	else
5000 		atomic_dec(&nr_freq_events);
5001 }
5002 
5003 static void unaccount_event(struct perf_event *event)
5004 {
5005 	bool dec = false;
5006 
5007 	if (event->parent)
5008 		return;
5009 
5010 	if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
5011 		dec = true;
5012 	if (event->attr.mmap || event->attr.mmap_data)
5013 		atomic_dec(&nr_mmap_events);
5014 	if (event->attr.build_id)
5015 		atomic_dec(&nr_build_id_events);
5016 	if (event->attr.comm)
5017 		atomic_dec(&nr_comm_events);
5018 	if (event->attr.namespaces)
5019 		atomic_dec(&nr_namespaces_events);
5020 	if (event->attr.cgroup)
5021 		atomic_dec(&nr_cgroup_events);
5022 	if (event->attr.task)
5023 		atomic_dec(&nr_task_events);
5024 	if (event->attr.freq)
5025 		unaccount_freq_event();
5026 	if (event->attr.context_switch) {
5027 		dec = true;
5028 		atomic_dec(&nr_switch_events);
5029 	}
5030 	if (is_cgroup_event(event))
5031 		dec = true;
5032 	if (has_branch_stack(event))
5033 		dec = true;
5034 	if (event->attr.ksymbol)
5035 		atomic_dec(&nr_ksymbol_events);
5036 	if (event->attr.bpf_event)
5037 		atomic_dec(&nr_bpf_events);
5038 	if (event->attr.text_poke)
5039 		atomic_dec(&nr_text_poke_events);
5040 
5041 	if (dec) {
5042 		if (!atomic_add_unless(&perf_sched_count, -1, 1))
5043 			schedule_delayed_work(&perf_sched_work, HZ);
5044 	}
5045 
5046 	unaccount_pmu_sb_event(event);
5047 }
5048 
5049 static void perf_sched_delayed(struct work_struct *work)
5050 {
5051 	mutex_lock(&perf_sched_mutex);
5052 	if (atomic_dec_and_test(&perf_sched_count))
5053 		static_branch_disable(&perf_sched_events);
5054 	mutex_unlock(&perf_sched_mutex);
5055 }
5056 
5057 /*
5058  * The following implement mutual exclusion of events on "exclusive" pmus
5059  * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
5060  * at a time, so we disallow creating events that might conflict, namely:
5061  *
5062  *  1) cpu-wide events in the presence of per-task events,
5063  *  2) per-task events in the presence of cpu-wide events,
5064  *  3) two matching events on the same perf_event_context.
5065  *
5066  * The former two cases are handled in the allocation path (perf_event_alloc(),
5067  * _free_event()), the latter -- before the first perf_install_in_context().
5068  */
5069 static int exclusive_event_init(struct perf_event *event)
5070 {
5071 	struct pmu *pmu = event->pmu;
5072 
5073 	if (!is_exclusive_pmu(pmu))
5074 		return 0;
5075 
5076 	/*
5077 	 * Prevent co-existence of per-task and cpu-wide events on the
5078 	 * same exclusive pmu.
5079 	 *
5080 	 * Negative pmu::exclusive_cnt means there are cpu-wide
5081 	 * events on this "exclusive" pmu, positive means there are
5082 	 * per-task events.
5083 	 *
5084 	 * Since this is called in perf_event_alloc() path, event::ctx
5085 	 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
5086 	 * to mean "per-task event", because unlike other attach states it
5087 	 * never gets cleared.
5088 	 */
5089 	if (event->attach_state & PERF_ATTACH_TASK) {
5090 		if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
5091 			return -EBUSY;
5092 	} else {
5093 		if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
5094 			return -EBUSY;
5095 	}
5096 
5097 	return 0;
5098 }
5099 
5100 static void exclusive_event_destroy(struct perf_event *event)
5101 {
5102 	struct pmu *pmu = event->pmu;
5103 
5104 	if (!is_exclusive_pmu(pmu))
5105 		return;
5106 
5107 	/* see comment in exclusive_event_init() */
5108 	if (event->attach_state & PERF_ATTACH_TASK)
5109 		atomic_dec(&pmu->exclusive_cnt);
5110 	else
5111 		atomic_inc(&pmu->exclusive_cnt);
5112 }
5113 
5114 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
5115 {
5116 	if ((e1->pmu == e2->pmu) &&
5117 	    (e1->cpu == e2->cpu ||
5118 	     e1->cpu == -1 ||
5119 	     e2->cpu == -1))
5120 		return true;
5121 	return false;
5122 }
5123 
5124 static bool exclusive_event_installable(struct perf_event *event,
5125 					struct perf_event_context *ctx)
5126 {
5127 	struct perf_event *iter_event;
5128 	struct pmu *pmu = event->pmu;
5129 
5130 	lockdep_assert_held(&ctx->mutex);
5131 
5132 	if (!is_exclusive_pmu(pmu))
5133 		return true;
5134 
5135 	list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
5136 		if (exclusive_event_match(iter_event, event))
5137 			return false;
5138 	}
5139 
5140 	return true;
5141 }
5142 
5143 static void perf_addr_filters_splice(struct perf_event *event,
5144 				       struct list_head *head);
5145 
5146 static void _free_event(struct perf_event *event)
5147 {
5148 	irq_work_sync(&event->pending_irq);
5149 
5150 	unaccount_event(event);
5151 
5152 	security_perf_event_free(event);
5153 
5154 	if (event->rb) {
5155 		/*
5156 		 * Can happen when we close an event with re-directed output.
5157 		 *
5158 		 * Since we have a 0 refcount, perf_mmap_close() will skip
5159 		 * over us; possibly making our ring_buffer_put() the last.
5160 		 */
5161 		mutex_lock(&event->mmap_mutex);
5162 		ring_buffer_attach(event, NULL);
5163 		mutex_unlock(&event->mmap_mutex);
5164 	}
5165 
5166 	if (is_cgroup_event(event))
5167 		perf_detach_cgroup(event);
5168 
5169 	if (!event->parent) {
5170 		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
5171 			put_callchain_buffers();
5172 	}
5173 
5174 	perf_event_free_bpf_prog(event);
5175 	perf_addr_filters_splice(event, NULL);
5176 	kfree(event->addr_filter_ranges);
5177 
5178 	if (event->destroy)
5179 		event->destroy(event);
5180 
5181 	/*
5182 	 * Must be after ->destroy(), due to uprobe_perf_close() using
5183 	 * hw.target.
5184 	 */
5185 	if (event->hw.target)
5186 		put_task_struct(event->hw.target);
5187 
5188 	if (event->pmu_ctx)
5189 		put_pmu_ctx(event->pmu_ctx);
5190 
5191 	/*
5192 	 * perf_event_free_task() relies on put_ctx() being 'last', in particular
5193 	 * all task references must be cleaned up.
5194 	 */
5195 	if (event->ctx)
5196 		put_ctx(event->ctx);
5197 
5198 	exclusive_event_destroy(event);
5199 	module_put(event->pmu->module);
5200 
5201 	call_rcu(&event->rcu_head, free_event_rcu);
5202 }
5203 
5204 /*
5205  * Used to free events which have a known refcount of 1, such as in error paths
5206  * where the event isn't exposed yet and inherited events.
5207  */
5208 static void free_event(struct perf_event *event)
5209 {
5210 	if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
5211 				"unexpected event refcount: %ld; ptr=%p\n",
5212 				atomic_long_read(&event->refcount), event)) {
5213 		/* leak to avoid use-after-free */
5214 		return;
5215 	}
5216 
5217 	_free_event(event);
5218 }
5219 
5220 /*
5221  * Remove user event from the owner task.
5222  */
5223 static void perf_remove_from_owner(struct perf_event *event)
5224 {
5225 	struct task_struct *owner;
5226 
5227 	rcu_read_lock();
5228 	/*
5229 	 * Matches the smp_store_release() in perf_event_exit_task(). If we
5230 	 * observe !owner it means the list deletion is complete and we can
5231 	 * indeed free this event, otherwise we need to serialize on
5232 	 * owner->perf_event_mutex.
5233 	 */
5234 	owner = READ_ONCE(event->owner);
5235 	if (owner) {
5236 		/*
5237 		 * Since delayed_put_task_struct() also drops the last
5238 		 * task reference we can safely take a new reference
5239 		 * while holding the rcu_read_lock().
5240 		 */
5241 		get_task_struct(owner);
5242 	}
5243 	rcu_read_unlock();
5244 
5245 	if (owner) {
5246 		/*
5247 		 * If we're here through perf_event_exit_task() we're already
5248 		 * holding ctx->mutex which would be an inversion wrt. the
5249 		 * normal lock order.
5250 		 *
5251 		 * However we can safely take this lock because its the child
5252 		 * ctx->mutex.
5253 		 */
5254 		mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
5255 
5256 		/*
5257 		 * We have to re-check the event->owner field, if it is cleared
5258 		 * we raced with perf_event_exit_task(), acquiring the mutex
5259 		 * ensured they're done, and we can proceed with freeing the
5260 		 * event.
5261 		 */
5262 		if (event->owner) {
5263 			list_del_init(&event->owner_entry);
5264 			smp_store_release(&event->owner, NULL);
5265 		}
5266 		mutex_unlock(&owner->perf_event_mutex);
5267 		put_task_struct(owner);
5268 	}
5269 }
5270 
5271 static void put_event(struct perf_event *event)
5272 {
5273 	if (!atomic_long_dec_and_test(&event->refcount))
5274 		return;
5275 
5276 	_free_event(event);
5277 }
5278 
5279 /*
5280  * Kill an event dead; while event:refcount will preserve the event
5281  * object, it will not preserve its functionality. Once the last 'user'
5282  * gives up the object, we'll destroy the thing.
5283  */
5284 int perf_event_release_kernel(struct perf_event *event)
5285 {
5286 	struct perf_event_context *ctx = event->ctx;
5287 	struct perf_event *child, *tmp;
5288 	LIST_HEAD(free_list);
5289 
5290 	/*
5291 	 * If we got here through err_alloc: free_event(event); we will not
5292 	 * have attached to a context yet.
5293 	 */
5294 	if (!ctx) {
5295 		WARN_ON_ONCE(event->attach_state &
5296 				(PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
5297 		goto no_ctx;
5298 	}
5299 
5300 	if (!is_kernel_event(event))
5301 		perf_remove_from_owner(event);
5302 
5303 	ctx = perf_event_ctx_lock(event);
5304 	WARN_ON_ONCE(ctx->parent_ctx);
5305 
5306 	/*
5307 	 * Mark this event as STATE_DEAD, there is no external reference to it
5308 	 * anymore.
5309 	 *
5310 	 * Anybody acquiring event->child_mutex after the below loop _must_
5311 	 * also see this, most importantly inherit_event() which will avoid
5312 	 * placing more children on the list.
5313 	 *
5314 	 * Thus this guarantees that we will in fact observe and kill _ALL_
5315 	 * child events.
5316 	 */
5317 	perf_remove_from_context(event, DETACH_GROUP|DETACH_DEAD);
5318 
5319 	perf_event_ctx_unlock(event, ctx);
5320 
5321 again:
5322 	mutex_lock(&event->child_mutex);
5323 	list_for_each_entry(child, &event->child_list, child_list) {
5324 
5325 		/*
5326 		 * Cannot change, child events are not migrated, see the
5327 		 * comment with perf_event_ctx_lock_nested().
5328 		 */
5329 		ctx = READ_ONCE(child->ctx);
5330 		/*
5331 		 * Since child_mutex nests inside ctx::mutex, we must jump
5332 		 * through hoops. We start by grabbing a reference on the ctx.
5333 		 *
5334 		 * Since the event cannot get freed while we hold the
5335 		 * child_mutex, the context must also exist and have a !0
5336 		 * reference count.
5337 		 */
5338 		get_ctx(ctx);
5339 
5340 		/*
5341 		 * Now that we have a ctx ref, we can drop child_mutex, and
5342 		 * acquire ctx::mutex without fear of it going away. Then we
5343 		 * can re-acquire child_mutex.
5344 		 */
5345 		mutex_unlock(&event->child_mutex);
5346 		mutex_lock(&ctx->mutex);
5347 		mutex_lock(&event->child_mutex);
5348 
5349 		/*
5350 		 * Now that we hold ctx::mutex and child_mutex, revalidate our
5351 		 * state, if child is still the first entry, it didn't get freed
5352 		 * and we can continue doing so.
5353 		 */
5354 		tmp = list_first_entry_or_null(&event->child_list,
5355 					       struct perf_event, child_list);
5356 		if (tmp == child) {
5357 			perf_remove_from_context(child, DETACH_GROUP);
5358 			list_move(&child->child_list, &free_list);
5359 			/*
5360 			 * This matches the refcount bump in inherit_event();
5361 			 * this can't be the last reference.
5362 			 */
5363 			put_event(event);
5364 		}
5365 
5366 		mutex_unlock(&event->child_mutex);
5367 		mutex_unlock(&ctx->mutex);
5368 		put_ctx(ctx);
5369 		goto again;
5370 	}
5371 	mutex_unlock(&event->child_mutex);
5372 
5373 	list_for_each_entry_safe(child, tmp, &free_list, child_list) {
5374 		void *var = &child->ctx->refcount;
5375 
5376 		list_del(&child->child_list);
5377 		free_event(child);
5378 
5379 		/*
5380 		 * Wake any perf_event_free_task() waiting for this event to be
5381 		 * freed.
5382 		 */
5383 		smp_mb(); /* pairs with wait_var_event() */
5384 		wake_up_var(var);
5385 	}
5386 
5387 no_ctx:
5388 	put_event(event); /* Must be the 'last' reference */
5389 	return 0;
5390 }
5391 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
5392 
5393 /*
5394  * Called when the last reference to the file is gone.
5395  */
5396 static int perf_release(struct inode *inode, struct file *file)
5397 {
5398 	perf_event_release_kernel(file->private_data);
5399 	return 0;
5400 }
5401 
5402 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5403 {
5404 	struct perf_event *child;
5405 	u64 total = 0;
5406 
5407 	*enabled = 0;
5408 	*running = 0;
5409 
5410 	mutex_lock(&event->child_mutex);
5411 
5412 	(void)perf_event_read(event, false);
5413 	total += perf_event_count(event);
5414 
5415 	*enabled += event->total_time_enabled +
5416 			atomic64_read(&event->child_total_time_enabled);
5417 	*running += event->total_time_running +
5418 			atomic64_read(&event->child_total_time_running);
5419 
5420 	list_for_each_entry(child, &event->child_list, child_list) {
5421 		(void)perf_event_read(child, false);
5422 		total += perf_event_count(child);
5423 		*enabled += child->total_time_enabled;
5424 		*running += child->total_time_running;
5425 	}
5426 	mutex_unlock(&event->child_mutex);
5427 
5428 	return total;
5429 }
5430 
5431 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5432 {
5433 	struct perf_event_context *ctx;
5434 	u64 count;
5435 
5436 	ctx = perf_event_ctx_lock(event);
5437 	count = __perf_event_read_value(event, enabled, running);
5438 	perf_event_ctx_unlock(event, ctx);
5439 
5440 	return count;
5441 }
5442 EXPORT_SYMBOL_GPL(perf_event_read_value);
5443 
5444 static int __perf_read_group_add(struct perf_event *leader,
5445 					u64 read_format, u64 *values)
5446 {
5447 	struct perf_event_context *ctx = leader->ctx;
5448 	struct perf_event *sub;
5449 	unsigned long flags;
5450 	int n = 1; /* skip @nr */
5451 	int ret;
5452 
5453 	ret = perf_event_read(leader, true);
5454 	if (ret)
5455 		return ret;
5456 
5457 	raw_spin_lock_irqsave(&ctx->lock, flags);
5458 
5459 	/*
5460 	 * Since we co-schedule groups, {enabled,running} times of siblings
5461 	 * will be identical to those of the leader, so we only publish one
5462 	 * set.
5463 	 */
5464 	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5465 		values[n++] += leader->total_time_enabled +
5466 			atomic64_read(&leader->child_total_time_enabled);
5467 	}
5468 
5469 	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5470 		values[n++] += leader->total_time_running +
5471 			atomic64_read(&leader->child_total_time_running);
5472 	}
5473 
5474 	/*
5475 	 * Write {count,id} tuples for every sibling.
5476 	 */
5477 	values[n++] += perf_event_count(leader);
5478 	if (read_format & PERF_FORMAT_ID)
5479 		values[n++] = primary_event_id(leader);
5480 	if (read_format & PERF_FORMAT_LOST)
5481 		values[n++] = atomic64_read(&leader->lost_samples);
5482 
5483 	for_each_sibling_event(sub, leader) {
5484 		values[n++] += perf_event_count(sub);
5485 		if (read_format & PERF_FORMAT_ID)
5486 			values[n++] = primary_event_id(sub);
5487 		if (read_format & PERF_FORMAT_LOST)
5488 			values[n++] = atomic64_read(&sub->lost_samples);
5489 	}
5490 
5491 	raw_spin_unlock_irqrestore(&ctx->lock, flags);
5492 	return 0;
5493 }
5494 
5495 static int perf_read_group(struct perf_event *event,
5496 				   u64 read_format, char __user *buf)
5497 {
5498 	struct perf_event *leader = event->group_leader, *child;
5499 	struct perf_event_context *ctx = leader->ctx;
5500 	int ret;
5501 	u64 *values;
5502 
5503 	lockdep_assert_held(&ctx->mutex);
5504 
5505 	values = kzalloc(event->read_size, GFP_KERNEL);
5506 	if (!values)
5507 		return -ENOMEM;
5508 
5509 	values[0] = 1 + leader->nr_siblings;
5510 
5511 	/*
5512 	 * By locking the child_mutex of the leader we effectively
5513 	 * lock the child list of all siblings.. XXX explain how.
5514 	 */
5515 	mutex_lock(&leader->child_mutex);
5516 
5517 	ret = __perf_read_group_add(leader, read_format, values);
5518 	if (ret)
5519 		goto unlock;
5520 
5521 	list_for_each_entry(child, &leader->child_list, child_list) {
5522 		ret = __perf_read_group_add(child, read_format, values);
5523 		if (ret)
5524 			goto unlock;
5525 	}
5526 
5527 	mutex_unlock(&leader->child_mutex);
5528 
5529 	ret = event->read_size;
5530 	if (copy_to_user(buf, values, event->read_size))
5531 		ret = -EFAULT;
5532 	goto out;
5533 
5534 unlock:
5535 	mutex_unlock(&leader->child_mutex);
5536 out:
5537 	kfree(values);
5538 	return ret;
5539 }
5540 
5541 static int perf_read_one(struct perf_event *event,
5542 				 u64 read_format, char __user *buf)
5543 {
5544 	u64 enabled, running;
5545 	u64 values[5];
5546 	int n = 0;
5547 
5548 	values[n++] = __perf_event_read_value(event, &enabled, &running);
5549 	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5550 		values[n++] = enabled;
5551 	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5552 		values[n++] = running;
5553 	if (read_format & PERF_FORMAT_ID)
5554 		values[n++] = primary_event_id(event);
5555 	if (read_format & PERF_FORMAT_LOST)
5556 		values[n++] = atomic64_read(&event->lost_samples);
5557 
5558 	if (copy_to_user(buf, values, n * sizeof(u64)))
5559 		return -EFAULT;
5560 
5561 	return n * sizeof(u64);
5562 }
5563 
5564 static bool is_event_hup(struct perf_event *event)
5565 {
5566 	bool no_children;
5567 
5568 	if (event->state > PERF_EVENT_STATE_EXIT)
5569 		return false;
5570 
5571 	mutex_lock(&event->child_mutex);
5572 	no_children = list_empty(&event->child_list);
5573 	mutex_unlock(&event->child_mutex);
5574 	return no_children;
5575 }
5576 
5577 /*
5578  * Read the performance event - simple non blocking version for now
5579  */
5580 static ssize_t
5581 __perf_read(struct perf_event *event, char __user *buf, size_t count)
5582 {
5583 	u64 read_format = event->attr.read_format;
5584 	int ret;
5585 
5586 	/*
5587 	 * Return end-of-file for a read on an event that is in
5588 	 * error state (i.e. because it was pinned but it couldn't be
5589 	 * scheduled on to the CPU at some point).
5590 	 */
5591 	if (event->state == PERF_EVENT_STATE_ERROR)
5592 		return 0;
5593 
5594 	if (count < event->read_size)
5595 		return -ENOSPC;
5596 
5597 	WARN_ON_ONCE(event->ctx->parent_ctx);
5598 	if (read_format & PERF_FORMAT_GROUP)
5599 		ret = perf_read_group(event, read_format, buf);
5600 	else
5601 		ret = perf_read_one(event, read_format, buf);
5602 
5603 	return ret;
5604 }
5605 
5606 static ssize_t
5607 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
5608 {
5609 	struct perf_event *event = file->private_data;
5610 	struct perf_event_context *ctx;
5611 	int ret;
5612 
5613 	ret = security_perf_event_read(event);
5614 	if (ret)
5615 		return ret;
5616 
5617 	ctx = perf_event_ctx_lock(event);
5618 	ret = __perf_read(event, buf, count);
5619 	perf_event_ctx_unlock(event, ctx);
5620 
5621 	return ret;
5622 }
5623 
5624 static __poll_t perf_poll(struct file *file, poll_table *wait)
5625 {
5626 	struct perf_event *event = file->private_data;
5627 	struct perf_buffer *rb;
5628 	__poll_t events = EPOLLHUP;
5629 
5630 	poll_wait(file, &event->waitq, wait);
5631 
5632 	if (is_event_hup(event))
5633 		return events;
5634 
5635 	/*
5636 	 * Pin the event->rb by taking event->mmap_mutex; otherwise
5637 	 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5638 	 */
5639 	mutex_lock(&event->mmap_mutex);
5640 	rb = event->rb;
5641 	if (rb)
5642 		events = atomic_xchg(&rb->poll, 0);
5643 	mutex_unlock(&event->mmap_mutex);
5644 	return events;
5645 }
5646 
5647 static void _perf_event_reset(struct perf_event *event)
5648 {
5649 	(void)perf_event_read(event, false);
5650 	local64_set(&event->count, 0);
5651 	perf_event_update_userpage(event);
5652 }
5653 
5654 /* Assume it's not an event with inherit set. */
5655 u64 perf_event_pause(struct perf_event *event, bool reset)
5656 {
5657 	struct perf_event_context *ctx;
5658 	u64 count;
5659 
5660 	ctx = perf_event_ctx_lock(event);
5661 	WARN_ON_ONCE(event->attr.inherit);
5662 	_perf_event_disable(event);
5663 	count = local64_read(&event->count);
5664 	if (reset)
5665 		local64_set(&event->count, 0);
5666 	perf_event_ctx_unlock(event, ctx);
5667 
5668 	return count;
5669 }
5670 EXPORT_SYMBOL_GPL(perf_event_pause);
5671 
5672 /*
5673  * Holding the top-level event's child_mutex means that any
5674  * descendant process that has inherited this event will block
5675  * in perf_event_exit_event() if it goes to exit, thus satisfying the
5676  * task existence requirements of perf_event_enable/disable.
5677  */
5678 static void perf_event_for_each_child(struct perf_event *event,
5679 					void (*func)(struct perf_event *))
5680 {
5681 	struct perf_event *child;
5682 
5683 	WARN_ON_ONCE(event->ctx->parent_ctx);
5684 
5685 	mutex_lock(&event->child_mutex);
5686 	func(event);
5687 	list_for_each_entry(child, &event->child_list, child_list)
5688 		func(child);
5689 	mutex_unlock(&event->child_mutex);
5690 }
5691 
5692 static void perf_event_for_each(struct perf_event *event,
5693 				  void (*func)(struct perf_event *))
5694 {
5695 	struct perf_event_context *ctx = event->ctx;
5696 	struct perf_event *sibling;
5697 
5698 	lockdep_assert_held(&ctx->mutex);
5699 
5700 	event = event->group_leader;
5701 
5702 	perf_event_for_each_child(event, func);
5703 	for_each_sibling_event(sibling, event)
5704 		perf_event_for_each_child(sibling, func);
5705 }
5706 
5707 static void __perf_event_period(struct perf_event *event,
5708 				struct perf_cpu_context *cpuctx,
5709 				struct perf_event_context *ctx,
5710 				void *info)
5711 {
5712 	u64 value = *((u64 *)info);
5713 	bool active;
5714 
5715 	if (event->attr.freq) {
5716 		event->attr.sample_freq = value;
5717 	} else {
5718 		event->attr.sample_period = value;
5719 		event->hw.sample_period = value;
5720 	}
5721 
5722 	active = (event->state == PERF_EVENT_STATE_ACTIVE);
5723 	if (active) {
5724 		perf_pmu_disable(event->pmu);
5725 		/*
5726 		 * We could be throttled; unthrottle now to avoid the tick
5727 		 * trying to unthrottle while we already re-started the event.
5728 		 */
5729 		if (event->hw.interrupts == MAX_INTERRUPTS) {
5730 			event->hw.interrupts = 0;
5731 			perf_log_throttle(event, 1);
5732 		}
5733 		event->pmu->stop(event, PERF_EF_UPDATE);
5734 	}
5735 
5736 	local64_set(&event->hw.period_left, 0);
5737 
5738 	if (active) {
5739 		event->pmu->start(event, PERF_EF_RELOAD);
5740 		perf_pmu_enable(event->pmu);
5741 	}
5742 }
5743 
5744 static int perf_event_check_period(struct perf_event *event, u64 value)
5745 {
5746 	return event->pmu->check_period(event, value);
5747 }
5748 
5749 static int _perf_event_period(struct perf_event *event, u64 value)
5750 {
5751 	if (!is_sampling_event(event))
5752 		return -EINVAL;
5753 
5754 	if (!value)
5755 		return -EINVAL;
5756 
5757 	if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5758 		return -EINVAL;
5759 
5760 	if (perf_event_check_period(event, value))
5761 		return -EINVAL;
5762 
5763 	if (!event->attr.freq && (value & (1ULL << 63)))
5764 		return -EINVAL;
5765 
5766 	event_function_call(event, __perf_event_period, &value);
5767 
5768 	return 0;
5769 }
5770 
5771 int perf_event_period(struct perf_event *event, u64 value)
5772 {
5773 	struct perf_event_context *ctx;
5774 	int ret;
5775 
5776 	ctx = perf_event_ctx_lock(event);
5777 	ret = _perf_event_period(event, value);
5778 	perf_event_ctx_unlock(event, ctx);
5779 
5780 	return ret;
5781 }
5782 EXPORT_SYMBOL_GPL(perf_event_period);
5783 
5784 static const struct file_operations perf_fops;
5785 
5786 static inline int perf_fget_light(int fd, struct fd *p)
5787 {
5788 	struct fd f = fdget(fd);
5789 	if (!f.file)
5790 		return -EBADF;
5791 
5792 	if (f.file->f_op != &perf_fops) {
5793 		fdput(f);
5794 		return -EBADF;
5795 	}
5796 	*p = f;
5797 	return 0;
5798 }
5799 
5800 static int perf_event_set_output(struct perf_event *event,
5801 				 struct perf_event *output_event);
5802 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5803 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5804 			  struct perf_event_attr *attr);
5805 
5806 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5807 {
5808 	void (*func)(struct perf_event *);
5809 	u32 flags = arg;
5810 
5811 	switch (cmd) {
5812 	case PERF_EVENT_IOC_ENABLE:
5813 		func = _perf_event_enable;
5814 		break;
5815 	case PERF_EVENT_IOC_DISABLE:
5816 		func = _perf_event_disable;
5817 		break;
5818 	case PERF_EVENT_IOC_RESET:
5819 		func = _perf_event_reset;
5820 		break;
5821 
5822 	case PERF_EVENT_IOC_REFRESH:
5823 		return _perf_event_refresh(event, arg);
5824 
5825 	case PERF_EVENT_IOC_PERIOD:
5826 	{
5827 		u64 value;
5828 
5829 		if (copy_from_user(&value, (u64 __user *)arg, sizeof(value)))
5830 			return -EFAULT;
5831 
5832 		return _perf_event_period(event, value);
5833 	}
5834 	case PERF_EVENT_IOC_ID:
5835 	{
5836 		u64 id = primary_event_id(event);
5837 
5838 		if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5839 			return -EFAULT;
5840 		return 0;
5841 	}
5842 
5843 	case PERF_EVENT_IOC_SET_OUTPUT:
5844 	{
5845 		int ret;
5846 		if (arg != -1) {
5847 			struct perf_event *output_event;
5848 			struct fd output;
5849 			ret = perf_fget_light(arg, &output);
5850 			if (ret)
5851 				return ret;
5852 			output_event = output.file->private_data;
5853 			ret = perf_event_set_output(event, output_event);
5854 			fdput(output);
5855 		} else {
5856 			ret = perf_event_set_output(event, NULL);
5857 		}
5858 		return ret;
5859 	}
5860 
5861 	case PERF_EVENT_IOC_SET_FILTER:
5862 		return perf_event_set_filter(event, (void __user *)arg);
5863 
5864 	case PERF_EVENT_IOC_SET_BPF:
5865 	{
5866 		struct bpf_prog *prog;
5867 		int err;
5868 
5869 		prog = bpf_prog_get(arg);
5870 		if (IS_ERR(prog))
5871 			return PTR_ERR(prog);
5872 
5873 		err = perf_event_set_bpf_prog(event, prog, 0);
5874 		if (err) {
5875 			bpf_prog_put(prog);
5876 			return err;
5877 		}
5878 
5879 		return 0;
5880 	}
5881 
5882 	case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5883 		struct perf_buffer *rb;
5884 
5885 		rcu_read_lock();
5886 		rb = rcu_dereference(event->rb);
5887 		if (!rb || !rb->nr_pages) {
5888 			rcu_read_unlock();
5889 			return -EINVAL;
5890 		}
5891 		rb_toggle_paused(rb, !!arg);
5892 		rcu_read_unlock();
5893 		return 0;
5894 	}
5895 
5896 	case PERF_EVENT_IOC_QUERY_BPF:
5897 		return perf_event_query_prog_array(event, (void __user *)arg);
5898 
5899 	case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5900 		struct perf_event_attr new_attr;
5901 		int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5902 					 &new_attr);
5903 
5904 		if (err)
5905 			return err;
5906 
5907 		return perf_event_modify_attr(event,  &new_attr);
5908 	}
5909 	default:
5910 		return -ENOTTY;
5911 	}
5912 
5913 	if (flags & PERF_IOC_FLAG_GROUP)
5914 		perf_event_for_each(event, func);
5915 	else
5916 		perf_event_for_each_child(event, func);
5917 
5918 	return 0;
5919 }
5920 
5921 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5922 {
5923 	struct perf_event *event = file->private_data;
5924 	struct perf_event_context *ctx;
5925 	long ret;
5926 
5927 	/* Treat ioctl like writes as it is likely a mutating operation. */
5928 	ret = security_perf_event_write(event);
5929 	if (ret)
5930 		return ret;
5931 
5932 	ctx = perf_event_ctx_lock(event);
5933 	ret = _perf_ioctl(event, cmd, arg);
5934 	perf_event_ctx_unlock(event, ctx);
5935 
5936 	return ret;
5937 }
5938 
5939 #ifdef CONFIG_COMPAT
5940 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5941 				unsigned long arg)
5942 {
5943 	switch (_IOC_NR(cmd)) {
5944 	case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5945 	case _IOC_NR(PERF_EVENT_IOC_ID):
5946 	case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5947 	case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5948 		/* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5949 		if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5950 			cmd &= ~IOCSIZE_MASK;
5951 			cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5952 		}
5953 		break;
5954 	}
5955 	return perf_ioctl(file, cmd, arg);
5956 }
5957 #else
5958 # define perf_compat_ioctl NULL
5959 #endif
5960 
5961 int perf_event_task_enable(void)
5962 {
5963 	struct perf_event_context *ctx;
5964 	struct perf_event *event;
5965 
5966 	mutex_lock(&current->perf_event_mutex);
5967 	list_for_each_entry(event, &current->perf_event_list, owner_entry) {
5968 		ctx = perf_event_ctx_lock(event);
5969 		perf_event_for_each_child(event, _perf_event_enable);
5970 		perf_event_ctx_unlock(event, ctx);
5971 	}
5972 	mutex_unlock(&current->perf_event_mutex);
5973 
5974 	return 0;
5975 }
5976 
5977 int perf_event_task_disable(void)
5978 {
5979 	struct perf_event_context *ctx;
5980 	struct perf_event *event;
5981 
5982 	mutex_lock(&current->perf_event_mutex);
5983 	list_for_each_entry(event, &current->perf_event_list, owner_entry) {
5984 		ctx = perf_event_ctx_lock(event);
5985 		perf_event_for_each_child(event, _perf_event_disable);
5986 		perf_event_ctx_unlock(event, ctx);
5987 	}
5988 	mutex_unlock(&current->perf_event_mutex);
5989 
5990 	return 0;
5991 }
5992 
5993 static int perf_event_index(struct perf_event *event)
5994 {
5995 	if (event->hw.state & PERF_HES_STOPPED)
5996 		return 0;
5997 
5998 	if (event->state != PERF_EVENT_STATE_ACTIVE)
5999 		return 0;
6000 
6001 	return event->pmu->event_idx(event);
6002 }
6003 
6004 static void perf_event_init_userpage(struct perf_event *event)
6005 {
6006 	struct perf_event_mmap_page *userpg;
6007 	struct perf_buffer *rb;
6008 
6009 	rcu_read_lock();
6010 	rb = rcu_dereference(event->rb);
6011 	if (!rb)
6012 		goto unlock;
6013 
6014 	userpg = rb->user_page;
6015 
6016 	/* Allow new userspace to detect that bit 0 is deprecated */
6017 	userpg->cap_bit0_is_deprecated = 1;
6018 	userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
6019 	userpg->data_offset = PAGE_SIZE;
6020 	userpg->data_size = perf_data_size(rb);
6021 
6022 unlock:
6023 	rcu_read_unlock();
6024 }
6025 
6026 void __weak arch_perf_update_userpage(
6027 	struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
6028 {
6029 }
6030 
6031 /*
6032  * Callers need to ensure there can be no nesting of this function, otherwise
6033  * the seqlock logic goes bad. We can not serialize this because the arch
6034  * code calls this from NMI context.
6035  */
6036 void perf_event_update_userpage(struct perf_event *event)
6037 {
6038 	struct perf_event_mmap_page *userpg;
6039 	struct perf_buffer *rb;
6040 	u64 enabled, running, now;
6041 
6042 	rcu_read_lock();
6043 	rb = rcu_dereference(event->rb);
6044 	if (!rb)
6045 		goto unlock;
6046 
6047 	/*
6048 	 * compute total_time_enabled, total_time_running
6049 	 * based on snapshot values taken when the event
6050 	 * was last scheduled in.
6051 	 *
6052 	 * we cannot simply called update_context_time()
6053 	 * because of locking issue as we can be called in
6054 	 * NMI context
6055 	 */
6056 	calc_timer_values(event, &now, &enabled, &running);
6057 
6058 	userpg = rb->user_page;
6059 	/*
6060 	 * Disable preemption to guarantee consistent time stamps are stored to
6061 	 * the user page.
6062 	 */
6063 	preempt_disable();
6064 	++userpg->lock;
6065 	barrier();
6066 	userpg->index = perf_event_index(event);
6067 	userpg->offset = perf_event_count(event);
6068 	if (userpg->index)
6069 		userpg->offset -= local64_read(&event->hw.prev_count);
6070 
6071 	userpg->time_enabled = enabled +
6072 			atomic64_read(&event->child_total_time_enabled);
6073 
6074 	userpg->time_running = running +
6075 			atomic64_read(&event->child_total_time_running);
6076 
6077 	arch_perf_update_userpage(event, userpg, now);
6078 
6079 	barrier();
6080 	++userpg->lock;
6081 	preempt_enable();
6082 unlock:
6083 	rcu_read_unlock();
6084 }
6085 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
6086 
6087 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
6088 {
6089 	struct perf_event *event = vmf->vma->vm_file->private_data;
6090 	struct perf_buffer *rb;
6091 	vm_fault_t ret = VM_FAULT_SIGBUS;
6092 
6093 	if (vmf->flags & FAULT_FLAG_MKWRITE) {
6094 		if (vmf->pgoff == 0)
6095 			ret = 0;
6096 		return ret;
6097 	}
6098 
6099 	rcu_read_lock();
6100 	rb = rcu_dereference(event->rb);
6101 	if (!rb)
6102 		goto unlock;
6103 
6104 	if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
6105 		goto unlock;
6106 
6107 	vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
6108 	if (!vmf->page)
6109 		goto unlock;
6110 
6111 	get_page(vmf->page);
6112 	vmf->page->mapping = vmf->vma->vm_file->f_mapping;
6113 	vmf->page->index   = vmf->pgoff;
6114 
6115 	ret = 0;
6116 unlock:
6117 	rcu_read_unlock();
6118 
6119 	return ret;
6120 }
6121 
6122 static void ring_buffer_attach(struct perf_event *event,
6123 			       struct perf_buffer *rb)
6124 {
6125 	struct perf_buffer *old_rb = NULL;
6126 	unsigned long flags;
6127 
6128 	WARN_ON_ONCE(event->parent);
6129 
6130 	if (event->rb) {
6131 		/*
6132 		 * Should be impossible, we set this when removing
6133 		 * event->rb_entry and wait/clear when adding event->rb_entry.
6134 		 */
6135 		WARN_ON_ONCE(event->rcu_pending);
6136 
6137 		old_rb = event->rb;
6138 		spin_lock_irqsave(&old_rb->event_lock, flags);
6139 		list_del_rcu(&event->rb_entry);
6140 		spin_unlock_irqrestore(&old_rb->event_lock, flags);
6141 
6142 		event->rcu_batches = get_state_synchronize_rcu();
6143 		event->rcu_pending = 1;
6144 	}
6145 
6146 	if (rb) {
6147 		if (event->rcu_pending) {
6148 			cond_synchronize_rcu(event->rcu_batches);
6149 			event->rcu_pending = 0;
6150 		}
6151 
6152 		spin_lock_irqsave(&rb->event_lock, flags);
6153 		list_add_rcu(&event->rb_entry, &rb->event_list);
6154 		spin_unlock_irqrestore(&rb->event_lock, flags);
6155 	}
6156 
6157 	/*
6158 	 * Avoid racing with perf_mmap_close(AUX): stop the event
6159 	 * before swizzling the event::rb pointer; if it's getting
6160 	 * unmapped, its aux_mmap_count will be 0 and it won't
6161 	 * restart. See the comment in __perf_pmu_output_stop().
6162 	 *
6163 	 * Data will inevitably be lost when set_output is done in
6164 	 * mid-air, but then again, whoever does it like this is
6165 	 * not in for the data anyway.
6166 	 */
6167 	if (has_aux(event))
6168 		perf_event_stop(event, 0);
6169 
6170 	rcu_assign_pointer(event->rb, rb);
6171 
6172 	if (old_rb) {
6173 		ring_buffer_put(old_rb);
6174 		/*
6175 		 * Since we detached before setting the new rb, so that we
6176 		 * could attach the new rb, we could have missed a wakeup.
6177 		 * Provide it now.
6178 		 */
6179 		wake_up_all(&event->waitq);
6180 	}
6181 }
6182 
6183 static void ring_buffer_wakeup(struct perf_event *event)
6184 {
6185 	struct perf_buffer *rb;
6186 
6187 	if (event->parent)
6188 		event = event->parent;
6189 
6190 	rcu_read_lock();
6191 	rb = rcu_dereference(event->rb);
6192 	if (rb) {
6193 		list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
6194 			wake_up_all(&event->waitq);
6195 	}
6196 	rcu_read_unlock();
6197 }
6198 
6199 struct perf_buffer *ring_buffer_get(struct perf_event *event)
6200 {
6201 	struct perf_buffer *rb;
6202 
6203 	if (event->parent)
6204 		event = event->parent;
6205 
6206 	rcu_read_lock();
6207 	rb = rcu_dereference(event->rb);
6208 	if (rb) {
6209 		if (!refcount_inc_not_zero(&rb->refcount))
6210 			rb = NULL;
6211 	}
6212 	rcu_read_unlock();
6213 
6214 	return rb;
6215 }
6216 
6217 void ring_buffer_put(struct perf_buffer *rb)
6218 {
6219 	if (!refcount_dec_and_test(&rb->refcount))
6220 		return;
6221 
6222 	WARN_ON_ONCE(!list_empty(&rb->event_list));
6223 
6224 	call_rcu(&rb->rcu_head, rb_free_rcu);
6225 }
6226 
6227 static void perf_mmap_open(struct vm_area_struct *vma)
6228 {
6229 	struct perf_event *event = vma->vm_file->private_data;
6230 
6231 	atomic_inc(&event->mmap_count);
6232 	atomic_inc(&event->rb->mmap_count);
6233 
6234 	if (vma->vm_pgoff)
6235 		atomic_inc(&event->rb->aux_mmap_count);
6236 
6237 	if (event->pmu->event_mapped)
6238 		event->pmu->event_mapped(event, vma->vm_mm);
6239 }
6240 
6241 static void perf_pmu_output_stop(struct perf_event *event);
6242 
6243 /*
6244  * A buffer can be mmap()ed multiple times; either directly through the same
6245  * event, or through other events by use of perf_event_set_output().
6246  *
6247  * In order to undo the VM accounting done by perf_mmap() we need to destroy
6248  * the buffer here, where we still have a VM context. This means we need
6249  * to detach all events redirecting to us.
6250  */
6251 static void perf_mmap_close(struct vm_area_struct *vma)
6252 {
6253 	struct perf_event *event = vma->vm_file->private_data;
6254 	struct perf_buffer *rb = ring_buffer_get(event);
6255 	struct user_struct *mmap_user = rb->mmap_user;
6256 	int mmap_locked = rb->mmap_locked;
6257 	unsigned long size = perf_data_size(rb);
6258 	bool detach_rest = false;
6259 
6260 	if (event->pmu->event_unmapped)
6261 		event->pmu->event_unmapped(event, vma->vm_mm);
6262 
6263 	/*
6264 	 * rb->aux_mmap_count will always drop before rb->mmap_count and
6265 	 * event->mmap_count, so it is ok to use event->mmap_mutex to
6266 	 * serialize with perf_mmap here.
6267 	 */
6268 	if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
6269 	    atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
6270 		/*
6271 		 * Stop all AUX events that are writing to this buffer,
6272 		 * so that we can free its AUX pages and corresponding PMU
6273 		 * data. Note that after rb::aux_mmap_count dropped to zero,
6274 		 * they won't start any more (see perf_aux_output_begin()).
6275 		 */
6276 		perf_pmu_output_stop(event);
6277 
6278 		/* now it's safe to free the pages */
6279 		atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm);
6280 		atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
6281 
6282 		/* this has to be the last one */
6283 		rb_free_aux(rb);
6284 		WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
6285 
6286 		mutex_unlock(&event->mmap_mutex);
6287 	}
6288 
6289 	if (atomic_dec_and_test(&rb->mmap_count))
6290 		detach_rest = true;
6291 
6292 	if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
6293 		goto out_put;
6294 
6295 	ring_buffer_attach(event, NULL);
6296 	mutex_unlock(&event->mmap_mutex);
6297 
6298 	/* If there's still other mmap()s of this buffer, we're done. */
6299 	if (!detach_rest)
6300 		goto out_put;
6301 
6302 	/*
6303 	 * No other mmap()s, detach from all other events that might redirect
6304 	 * into the now unreachable buffer. Somewhat complicated by the
6305 	 * fact that rb::event_lock otherwise nests inside mmap_mutex.
6306 	 */
6307 again:
6308 	rcu_read_lock();
6309 	list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
6310 		if (!atomic_long_inc_not_zero(&event->refcount)) {
6311 			/*
6312 			 * This event is en-route to free_event() which will
6313 			 * detach it and remove it from the list.
6314 			 */
6315 			continue;
6316 		}
6317 		rcu_read_unlock();
6318 
6319 		mutex_lock(&event->mmap_mutex);
6320 		/*
6321 		 * Check we didn't race with perf_event_set_output() which can
6322 		 * swizzle the rb from under us while we were waiting to
6323 		 * acquire mmap_mutex.
6324 		 *
6325 		 * If we find a different rb; ignore this event, a next
6326 		 * iteration will no longer find it on the list. We have to
6327 		 * still restart the iteration to make sure we're not now
6328 		 * iterating the wrong list.
6329 		 */
6330 		if (event->rb == rb)
6331 			ring_buffer_attach(event, NULL);
6332 
6333 		mutex_unlock(&event->mmap_mutex);
6334 		put_event(event);
6335 
6336 		/*
6337 		 * Restart the iteration; either we're on the wrong list or
6338 		 * destroyed its integrity by doing a deletion.
6339 		 */
6340 		goto again;
6341 	}
6342 	rcu_read_unlock();
6343 
6344 	/*
6345 	 * It could be there's still a few 0-ref events on the list; they'll
6346 	 * get cleaned up by free_event() -- they'll also still have their
6347 	 * ref on the rb and will free it whenever they are done with it.
6348 	 *
6349 	 * Aside from that, this buffer is 'fully' detached and unmapped,
6350 	 * undo the VM accounting.
6351 	 */
6352 
6353 	atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
6354 			&mmap_user->locked_vm);
6355 	atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
6356 	free_uid(mmap_user);
6357 
6358 out_put:
6359 	ring_buffer_put(rb); /* could be last */
6360 }
6361 
6362 static const struct vm_operations_struct perf_mmap_vmops = {
6363 	.open		= perf_mmap_open,
6364 	.close		= perf_mmap_close, /* non mergeable */
6365 	.fault		= perf_mmap_fault,
6366 	.page_mkwrite	= perf_mmap_fault,
6367 };
6368 
6369 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
6370 {
6371 	struct perf_event *event = file->private_data;
6372 	unsigned long user_locked, user_lock_limit;
6373 	struct user_struct *user = current_user();
6374 	struct perf_buffer *rb = NULL;
6375 	unsigned long locked, lock_limit;
6376 	unsigned long vma_size;
6377 	unsigned long nr_pages;
6378 	long user_extra = 0, extra = 0;
6379 	int ret = 0, flags = 0;
6380 
6381 	/*
6382 	 * Don't allow mmap() of inherited per-task counters. This would
6383 	 * create a performance issue due to all children writing to the
6384 	 * same rb.
6385 	 */
6386 	if (event->cpu == -1 && event->attr.inherit)
6387 		return -EINVAL;
6388 
6389 	if (!(vma->vm_flags & VM_SHARED))
6390 		return -EINVAL;
6391 
6392 	ret = security_perf_event_read(event);
6393 	if (ret)
6394 		return ret;
6395 
6396 	vma_size = vma->vm_end - vma->vm_start;
6397 
6398 	if (vma->vm_pgoff == 0) {
6399 		nr_pages = (vma_size / PAGE_SIZE) - 1;
6400 	} else {
6401 		/*
6402 		 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
6403 		 * mapped, all subsequent mappings should have the same size
6404 		 * and offset. Must be above the normal perf buffer.
6405 		 */
6406 		u64 aux_offset, aux_size;
6407 
6408 		if (!event->rb)
6409 			return -EINVAL;
6410 
6411 		nr_pages = vma_size / PAGE_SIZE;
6412 
6413 		mutex_lock(&event->mmap_mutex);
6414 		ret = -EINVAL;
6415 
6416 		rb = event->rb;
6417 		if (!rb)
6418 			goto aux_unlock;
6419 
6420 		aux_offset = READ_ONCE(rb->user_page->aux_offset);
6421 		aux_size = READ_ONCE(rb->user_page->aux_size);
6422 
6423 		if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
6424 			goto aux_unlock;
6425 
6426 		if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
6427 			goto aux_unlock;
6428 
6429 		/* already mapped with a different offset */
6430 		if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
6431 			goto aux_unlock;
6432 
6433 		if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
6434 			goto aux_unlock;
6435 
6436 		/* already mapped with a different size */
6437 		if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
6438 			goto aux_unlock;
6439 
6440 		if (!is_power_of_2(nr_pages))
6441 			goto aux_unlock;
6442 
6443 		if (!atomic_inc_not_zero(&rb->mmap_count))
6444 			goto aux_unlock;
6445 
6446 		if (rb_has_aux(rb)) {
6447 			atomic_inc(&rb->aux_mmap_count);
6448 			ret = 0;
6449 			goto unlock;
6450 		}
6451 
6452 		atomic_set(&rb->aux_mmap_count, 1);
6453 		user_extra = nr_pages;
6454 
6455 		goto accounting;
6456 	}
6457 
6458 	/*
6459 	 * If we have rb pages ensure they're a power-of-two number, so we
6460 	 * can do bitmasks instead of modulo.
6461 	 */
6462 	if (nr_pages != 0 && !is_power_of_2(nr_pages))
6463 		return -EINVAL;
6464 
6465 	if (vma_size != PAGE_SIZE * (1 + nr_pages))
6466 		return -EINVAL;
6467 
6468 	WARN_ON_ONCE(event->ctx->parent_ctx);
6469 again:
6470 	mutex_lock(&event->mmap_mutex);
6471 	if (event->rb) {
6472 		if (data_page_nr(event->rb) != nr_pages) {
6473 			ret = -EINVAL;
6474 			goto unlock;
6475 		}
6476 
6477 		if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
6478 			/*
6479 			 * Raced against perf_mmap_close(); remove the
6480 			 * event and try again.
6481 			 */
6482 			ring_buffer_attach(event, NULL);
6483 			mutex_unlock(&event->mmap_mutex);
6484 			goto again;
6485 		}
6486 
6487 		goto unlock;
6488 	}
6489 
6490 	user_extra = nr_pages + 1;
6491 
6492 accounting:
6493 	user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
6494 
6495 	/*
6496 	 * Increase the limit linearly with more CPUs:
6497 	 */
6498 	user_lock_limit *= num_online_cpus();
6499 
6500 	user_locked = atomic_long_read(&user->locked_vm);
6501 
6502 	/*
6503 	 * sysctl_perf_event_mlock may have changed, so that
6504 	 *     user->locked_vm > user_lock_limit
6505 	 */
6506 	if (user_locked > user_lock_limit)
6507 		user_locked = user_lock_limit;
6508 	user_locked += user_extra;
6509 
6510 	if (user_locked > user_lock_limit) {
6511 		/*
6512 		 * charge locked_vm until it hits user_lock_limit;
6513 		 * charge the rest from pinned_vm
6514 		 */
6515 		extra = user_locked - user_lock_limit;
6516 		user_extra -= extra;
6517 	}
6518 
6519 	lock_limit = rlimit(RLIMIT_MEMLOCK);
6520 	lock_limit >>= PAGE_SHIFT;
6521 	locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
6522 
6523 	if ((locked > lock_limit) && perf_is_paranoid() &&
6524 		!capable(CAP_IPC_LOCK)) {
6525 		ret = -EPERM;
6526 		goto unlock;
6527 	}
6528 
6529 	WARN_ON(!rb && event->rb);
6530 
6531 	if (vma->vm_flags & VM_WRITE)
6532 		flags |= RING_BUFFER_WRITABLE;
6533 
6534 	if (!rb) {
6535 		rb = rb_alloc(nr_pages,
6536 			      event->attr.watermark ? event->attr.wakeup_watermark : 0,
6537 			      event->cpu, flags);
6538 
6539 		if (!rb) {
6540 			ret = -ENOMEM;
6541 			goto unlock;
6542 		}
6543 
6544 		atomic_set(&rb->mmap_count, 1);
6545 		rb->mmap_user = get_current_user();
6546 		rb->mmap_locked = extra;
6547 
6548 		ring_buffer_attach(event, rb);
6549 
6550 		perf_event_update_time(event);
6551 		perf_event_init_userpage(event);
6552 		perf_event_update_userpage(event);
6553 	} else {
6554 		ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
6555 				   event->attr.aux_watermark, flags);
6556 		if (!ret)
6557 			rb->aux_mmap_locked = extra;
6558 	}
6559 
6560 unlock:
6561 	if (!ret) {
6562 		atomic_long_add(user_extra, &user->locked_vm);
6563 		atomic64_add(extra, &vma->vm_mm->pinned_vm);
6564 
6565 		atomic_inc(&event->mmap_count);
6566 	} else if (rb) {
6567 		atomic_dec(&rb->mmap_count);
6568 	}
6569 aux_unlock:
6570 	mutex_unlock(&event->mmap_mutex);
6571 
6572 	/*
6573 	 * Since pinned accounting is per vm we cannot allow fork() to copy our
6574 	 * vma.
6575 	 */
6576 	vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
6577 	vma->vm_ops = &perf_mmap_vmops;
6578 
6579 	if (event->pmu->event_mapped)
6580 		event->pmu->event_mapped(event, vma->vm_mm);
6581 
6582 	return ret;
6583 }
6584 
6585 static int perf_fasync(int fd, struct file *filp, int on)
6586 {
6587 	struct inode *inode = file_inode(filp);
6588 	struct perf_event *event = filp->private_data;
6589 	int retval;
6590 
6591 	inode_lock(inode);
6592 	retval = fasync_helper(fd, filp, on, &event->fasync);
6593 	inode_unlock(inode);
6594 
6595 	if (retval < 0)
6596 		return retval;
6597 
6598 	return 0;
6599 }
6600 
6601 static const struct file_operations perf_fops = {
6602 	.llseek			= no_llseek,
6603 	.release		= perf_release,
6604 	.read			= perf_read,
6605 	.poll			= perf_poll,
6606 	.unlocked_ioctl		= perf_ioctl,
6607 	.compat_ioctl		= perf_compat_ioctl,
6608 	.mmap			= perf_mmap,
6609 	.fasync			= perf_fasync,
6610 };
6611 
6612 /*
6613  * Perf event wakeup
6614  *
6615  * If there's data, ensure we set the poll() state and publish everything
6616  * to user-space before waking everybody up.
6617  */
6618 
6619 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
6620 {
6621 	/* only the parent has fasync state */
6622 	if (event->parent)
6623 		event = event->parent;
6624 	return &event->fasync;
6625 }
6626 
6627 void perf_event_wakeup(struct perf_event *event)
6628 {
6629 	ring_buffer_wakeup(event);
6630 
6631 	if (event->pending_kill) {
6632 		kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
6633 		event->pending_kill = 0;
6634 	}
6635 }
6636 
6637 static void perf_sigtrap(struct perf_event *event)
6638 {
6639 	/*
6640 	 * We'd expect this to only occur if the irq_work is delayed and either
6641 	 * ctx->task or current has changed in the meantime. This can be the
6642 	 * case on architectures that do not implement arch_irq_work_raise().
6643 	 */
6644 	if (WARN_ON_ONCE(event->ctx->task != current))
6645 		return;
6646 
6647 	/*
6648 	 * Both perf_pending_task() and perf_pending_irq() can race with the
6649 	 * task exiting.
6650 	 */
6651 	if (current->flags & PF_EXITING)
6652 		return;
6653 
6654 	send_sig_perf((void __user *)event->pending_addr,
6655 		      event->attr.type, event->attr.sig_data);
6656 }
6657 
6658 /*
6659  * Deliver the pending work in-event-context or follow the context.
6660  */
6661 static void __perf_pending_irq(struct perf_event *event)
6662 {
6663 	int cpu = READ_ONCE(event->oncpu);
6664 
6665 	/*
6666 	 * If the event isn't running; we done. event_sched_out() will have
6667 	 * taken care of things.
6668 	 */
6669 	if (cpu < 0)
6670 		return;
6671 
6672 	/*
6673 	 * Yay, we hit home and are in the context of the event.
6674 	 */
6675 	if (cpu == smp_processor_id()) {
6676 		if (event->pending_sigtrap) {
6677 			event->pending_sigtrap = 0;
6678 			perf_sigtrap(event);
6679 			local_dec(&event->ctx->nr_pending);
6680 		}
6681 		if (event->pending_disable) {
6682 			event->pending_disable = 0;
6683 			perf_event_disable_local(event);
6684 		}
6685 		return;
6686 	}
6687 
6688 	/*
6689 	 *  CPU-A			CPU-B
6690 	 *
6691 	 *  perf_event_disable_inatomic()
6692 	 *    @pending_disable = CPU-A;
6693 	 *    irq_work_queue();
6694 	 *
6695 	 *  sched-out
6696 	 *    @pending_disable = -1;
6697 	 *
6698 	 *				sched-in
6699 	 *				perf_event_disable_inatomic()
6700 	 *				  @pending_disable = CPU-B;
6701 	 *				  irq_work_queue(); // FAILS
6702 	 *
6703 	 *  irq_work_run()
6704 	 *    perf_pending_irq()
6705 	 *
6706 	 * But the event runs on CPU-B and wants disabling there.
6707 	 */
6708 	irq_work_queue_on(&event->pending_irq, cpu);
6709 }
6710 
6711 static void perf_pending_irq(struct irq_work *entry)
6712 {
6713 	struct perf_event *event = container_of(entry, struct perf_event, pending_irq);
6714 	int rctx;
6715 
6716 	/*
6717 	 * If we 'fail' here, that's OK, it means recursion is already disabled
6718 	 * and we won't recurse 'further'.
6719 	 */
6720 	rctx = perf_swevent_get_recursion_context();
6721 
6722 	/*
6723 	 * The wakeup isn't bound to the context of the event -- it can happen
6724 	 * irrespective of where the event is.
6725 	 */
6726 	if (event->pending_wakeup) {
6727 		event->pending_wakeup = 0;
6728 		perf_event_wakeup(event);
6729 	}
6730 
6731 	__perf_pending_irq(event);
6732 
6733 	if (rctx >= 0)
6734 		perf_swevent_put_recursion_context(rctx);
6735 }
6736 
6737 static void perf_pending_task(struct callback_head *head)
6738 {
6739 	struct perf_event *event = container_of(head, struct perf_event, pending_task);
6740 	int rctx;
6741 
6742 	/*
6743 	 * If we 'fail' here, that's OK, it means recursion is already disabled
6744 	 * and we won't recurse 'further'.
6745 	 */
6746 	preempt_disable_notrace();
6747 	rctx = perf_swevent_get_recursion_context();
6748 
6749 	if (event->pending_work) {
6750 		event->pending_work = 0;
6751 		perf_sigtrap(event);
6752 		local_dec(&event->ctx->nr_pending);
6753 	}
6754 
6755 	if (rctx >= 0)
6756 		perf_swevent_put_recursion_context(rctx);
6757 	preempt_enable_notrace();
6758 
6759 	put_event(event);
6760 }
6761 
6762 #ifdef CONFIG_GUEST_PERF_EVENTS
6763 struct perf_guest_info_callbacks __rcu *perf_guest_cbs;
6764 
6765 DEFINE_STATIC_CALL_RET0(__perf_guest_state, *perf_guest_cbs->state);
6766 DEFINE_STATIC_CALL_RET0(__perf_guest_get_ip, *perf_guest_cbs->get_ip);
6767 DEFINE_STATIC_CALL_RET0(__perf_guest_handle_intel_pt_intr, *perf_guest_cbs->handle_intel_pt_intr);
6768 
6769 void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6770 {
6771 	if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs)))
6772 		return;
6773 
6774 	rcu_assign_pointer(perf_guest_cbs, cbs);
6775 	static_call_update(__perf_guest_state, cbs->state);
6776 	static_call_update(__perf_guest_get_ip, cbs->get_ip);
6777 
6778 	/* Implementing ->handle_intel_pt_intr is optional. */
6779 	if (cbs->handle_intel_pt_intr)
6780 		static_call_update(__perf_guest_handle_intel_pt_intr,
6781 				   cbs->handle_intel_pt_intr);
6782 }
6783 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6784 
6785 void perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6786 {
6787 	if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs) != cbs))
6788 		return;
6789 
6790 	rcu_assign_pointer(perf_guest_cbs, NULL);
6791 	static_call_update(__perf_guest_state, (void *)&__static_call_return0);
6792 	static_call_update(__perf_guest_get_ip, (void *)&__static_call_return0);
6793 	static_call_update(__perf_guest_handle_intel_pt_intr,
6794 			   (void *)&__static_call_return0);
6795 	synchronize_rcu();
6796 }
6797 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6798 #endif
6799 
6800 static void
6801 perf_output_sample_regs(struct perf_output_handle *handle,
6802 			struct pt_regs *regs, u64 mask)
6803 {
6804 	int bit;
6805 	DECLARE_BITMAP(_mask, 64);
6806 
6807 	bitmap_from_u64(_mask, mask);
6808 	for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6809 		u64 val;
6810 
6811 		val = perf_reg_value(regs, bit);
6812 		perf_output_put(handle, val);
6813 	}
6814 }
6815 
6816 static void perf_sample_regs_user(struct perf_regs *regs_user,
6817 				  struct pt_regs *regs)
6818 {
6819 	if (user_mode(regs)) {
6820 		regs_user->abi = perf_reg_abi(current);
6821 		regs_user->regs = regs;
6822 	} else if (!(current->flags & PF_KTHREAD)) {
6823 		perf_get_regs_user(regs_user, regs);
6824 	} else {
6825 		regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6826 		regs_user->regs = NULL;
6827 	}
6828 }
6829 
6830 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6831 				  struct pt_regs *regs)
6832 {
6833 	regs_intr->regs = regs;
6834 	regs_intr->abi  = perf_reg_abi(current);
6835 }
6836 
6837 
6838 /*
6839  * Get remaining task size from user stack pointer.
6840  *
6841  * It'd be better to take stack vma map and limit this more
6842  * precisely, but there's no way to get it safely under interrupt,
6843  * so using TASK_SIZE as limit.
6844  */
6845 static u64 perf_ustack_task_size(struct pt_regs *regs)
6846 {
6847 	unsigned long addr = perf_user_stack_pointer(regs);
6848 
6849 	if (!addr || addr >= TASK_SIZE)
6850 		return 0;
6851 
6852 	return TASK_SIZE - addr;
6853 }
6854 
6855 static u16
6856 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6857 			struct pt_regs *regs)
6858 {
6859 	u64 task_size;
6860 
6861 	/* No regs, no stack pointer, no dump. */
6862 	if (!regs)
6863 		return 0;
6864 
6865 	/*
6866 	 * Check if we fit in with the requested stack size into the:
6867 	 * - TASK_SIZE
6868 	 *   If we don't, we limit the size to the TASK_SIZE.
6869 	 *
6870 	 * - remaining sample size
6871 	 *   If we don't, we customize the stack size to
6872 	 *   fit in to the remaining sample size.
6873 	 */
6874 
6875 	task_size  = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6876 	stack_size = min(stack_size, (u16) task_size);
6877 
6878 	/* Current header size plus static size and dynamic size. */
6879 	header_size += 2 * sizeof(u64);
6880 
6881 	/* Do we fit in with the current stack dump size? */
6882 	if ((u16) (header_size + stack_size) < header_size) {
6883 		/*
6884 		 * If we overflow the maximum size for the sample,
6885 		 * we customize the stack dump size to fit in.
6886 		 */
6887 		stack_size = USHRT_MAX - header_size - sizeof(u64);
6888 		stack_size = round_up(stack_size, sizeof(u64));
6889 	}
6890 
6891 	return stack_size;
6892 }
6893 
6894 static void
6895 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6896 			  struct pt_regs *regs)
6897 {
6898 	/* Case of a kernel thread, nothing to dump */
6899 	if (!regs) {
6900 		u64 size = 0;
6901 		perf_output_put(handle, size);
6902 	} else {
6903 		unsigned long sp;
6904 		unsigned int rem;
6905 		u64 dyn_size;
6906 
6907 		/*
6908 		 * We dump:
6909 		 * static size
6910 		 *   - the size requested by user or the best one we can fit
6911 		 *     in to the sample max size
6912 		 * data
6913 		 *   - user stack dump data
6914 		 * dynamic size
6915 		 *   - the actual dumped size
6916 		 */
6917 
6918 		/* Static size. */
6919 		perf_output_put(handle, dump_size);
6920 
6921 		/* Data. */
6922 		sp = perf_user_stack_pointer(regs);
6923 		rem = __output_copy_user(handle, (void *) sp, dump_size);
6924 		dyn_size = dump_size - rem;
6925 
6926 		perf_output_skip(handle, rem);
6927 
6928 		/* Dynamic size. */
6929 		perf_output_put(handle, dyn_size);
6930 	}
6931 }
6932 
6933 static unsigned long perf_prepare_sample_aux(struct perf_event *event,
6934 					  struct perf_sample_data *data,
6935 					  size_t size)
6936 {
6937 	struct perf_event *sampler = event->aux_event;
6938 	struct perf_buffer *rb;
6939 
6940 	data->aux_size = 0;
6941 
6942 	if (!sampler)
6943 		goto out;
6944 
6945 	if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE))
6946 		goto out;
6947 
6948 	if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id()))
6949 		goto out;
6950 
6951 	rb = ring_buffer_get(sampler);
6952 	if (!rb)
6953 		goto out;
6954 
6955 	/*
6956 	 * If this is an NMI hit inside sampling code, don't take
6957 	 * the sample. See also perf_aux_sample_output().
6958 	 */
6959 	if (READ_ONCE(rb->aux_in_sampling)) {
6960 		data->aux_size = 0;
6961 	} else {
6962 		size = min_t(size_t, size, perf_aux_size(rb));
6963 		data->aux_size = ALIGN(size, sizeof(u64));
6964 	}
6965 	ring_buffer_put(rb);
6966 
6967 out:
6968 	return data->aux_size;
6969 }
6970 
6971 static long perf_pmu_snapshot_aux(struct perf_buffer *rb,
6972                                  struct perf_event *event,
6973                                  struct perf_output_handle *handle,
6974                                  unsigned long size)
6975 {
6976 	unsigned long flags;
6977 	long ret;
6978 
6979 	/*
6980 	 * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler
6981 	 * paths. If we start calling them in NMI context, they may race with
6982 	 * the IRQ ones, that is, for example, re-starting an event that's just
6983 	 * been stopped, which is why we're using a separate callback that
6984 	 * doesn't change the event state.
6985 	 *
6986 	 * IRQs need to be disabled to prevent IPIs from racing with us.
6987 	 */
6988 	local_irq_save(flags);
6989 	/*
6990 	 * Guard against NMI hits inside the critical section;
6991 	 * see also perf_prepare_sample_aux().
6992 	 */
6993 	WRITE_ONCE(rb->aux_in_sampling, 1);
6994 	barrier();
6995 
6996 	ret = event->pmu->snapshot_aux(event, handle, size);
6997 
6998 	barrier();
6999 	WRITE_ONCE(rb->aux_in_sampling, 0);
7000 	local_irq_restore(flags);
7001 
7002 	return ret;
7003 }
7004 
7005 static void perf_aux_sample_output(struct perf_event *event,
7006 				   struct perf_output_handle *handle,
7007 				   struct perf_sample_data *data)
7008 {
7009 	struct perf_event *sampler = event->aux_event;
7010 	struct perf_buffer *rb;
7011 	unsigned long pad;
7012 	long size;
7013 
7014 	if (WARN_ON_ONCE(!sampler || !data->aux_size))
7015 		return;
7016 
7017 	rb = ring_buffer_get(sampler);
7018 	if (!rb)
7019 		return;
7020 
7021 	size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size);
7022 
7023 	/*
7024 	 * An error here means that perf_output_copy() failed (returned a
7025 	 * non-zero surplus that it didn't copy), which in its current
7026 	 * enlightened implementation is not possible. If that changes, we'd
7027 	 * like to know.
7028 	 */
7029 	if (WARN_ON_ONCE(size < 0))
7030 		goto out_put;
7031 
7032 	/*
7033 	 * The pad comes from ALIGN()ing data->aux_size up to u64 in
7034 	 * perf_prepare_sample_aux(), so should not be more than that.
7035 	 */
7036 	pad = data->aux_size - size;
7037 	if (WARN_ON_ONCE(pad >= sizeof(u64)))
7038 		pad = 8;
7039 
7040 	if (pad) {
7041 		u64 zero = 0;
7042 		perf_output_copy(handle, &zero, pad);
7043 	}
7044 
7045 out_put:
7046 	ring_buffer_put(rb);
7047 }
7048 
7049 static void __perf_event_header__init_id(struct perf_event_header *header,
7050 					 struct perf_sample_data *data,
7051 					 struct perf_event *event,
7052 					 u64 sample_type)
7053 {
7054 	data->type = event->attr.sample_type;
7055 	header->size += event->id_header_size;
7056 
7057 	if (sample_type & PERF_SAMPLE_TID) {
7058 		/* namespace issues */
7059 		data->tid_entry.pid = perf_event_pid(event, current);
7060 		data->tid_entry.tid = perf_event_tid(event, current);
7061 	}
7062 
7063 	if (sample_type & PERF_SAMPLE_TIME)
7064 		data->time = perf_event_clock(event);
7065 
7066 	if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
7067 		data->id = primary_event_id(event);
7068 
7069 	if (sample_type & PERF_SAMPLE_STREAM_ID)
7070 		data->stream_id = event->id;
7071 
7072 	if (sample_type & PERF_SAMPLE_CPU) {
7073 		data->cpu_entry.cpu	 = raw_smp_processor_id();
7074 		data->cpu_entry.reserved = 0;
7075 	}
7076 }
7077 
7078 void perf_event_header__init_id(struct perf_event_header *header,
7079 				struct perf_sample_data *data,
7080 				struct perf_event *event)
7081 {
7082 	if (event->attr.sample_id_all)
7083 		__perf_event_header__init_id(header, data, event, event->attr.sample_type);
7084 }
7085 
7086 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
7087 					   struct perf_sample_data *data)
7088 {
7089 	u64 sample_type = data->type;
7090 
7091 	if (sample_type & PERF_SAMPLE_TID)
7092 		perf_output_put(handle, data->tid_entry);
7093 
7094 	if (sample_type & PERF_SAMPLE_TIME)
7095 		perf_output_put(handle, data->time);
7096 
7097 	if (sample_type & PERF_SAMPLE_ID)
7098 		perf_output_put(handle, data->id);
7099 
7100 	if (sample_type & PERF_SAMPLE_STREAM_ID)
7101 		perf_output_put(handle, data->stream_id);
7102 
7103 	if (sample_type & PERF_SAMPLE_CPU)
7104 		perf_output_put(handle, data->cpu_entry);
7105 
7106 	if (sample_type & PERF_SAMPLE_IDENTIFIER)
7107 		perf_output_put(handle, data->id);
7108 }
7109 
7110 void perf_event__output_id_sample(struct perf_event *event,
7111 				  struct perf_output_handle *handle,
7112 				  struct perf_sample_data *sample)
7113 {
7114 	if (event->attr.sample_id_all)
7115 		__perf_event__output_id_sample(handle, sample);
7116 }
7117 
7118 static void perf_output_read_one(struct perf_output_handle *handle,
7119 				 struct perf_event *event,
7120 				 u64 enabled, u64 running)
7121 {
7122 	u64 read_format = event->attr.read_format;
7123 	u64 values[5];
7124 	int n = 0;
7125 
7126 	values[n++] = perf_event_count(event);
7127 	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
7128 		values[n++] = enabled +
7129 			atomic64_read(&event->child_total_time_enabled);
7130 	}
7131 	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
7132 		values[n++] = running +
7133 			atomic64_read(&event->child_total_time_running);
7134 	}
7135 	if (read_format & PERF_FORMAT_ID)
7136 		values[n++] = primary_event_id(event);
7137 	if (read_format & PERF_FORMAT_LOST)
7138 		values[n++] = atomic64_read(&event->lost_samples);
7139 
7140 	__output_copy(handle, values, n * sizeof(u64));
7141 }
7142 
7143 static void perf_output_read_group(struct perf_output_handle *handle,
7144 			    struct perf_event *event,
7145 			    u64 enabled, u64 running)
7146 {
7147 	struct perf_event *leader = event->group_leader, *sub;
7148 	u64 read_format = event->attr.read_format;
7149 	unsigned long flags;
7150 	u64 values[6];
7151 	int n = 0;
7152 
7153 	/*
7154 	 * Disabling interrupts avoids all counter scheduling
7155 	 * (context switches, timer based rotation and IPIs).
7156 	 */
7157 	local_irq_save(flags);
7158 
7159 	values[n++] = 1 + leader->nr_siblings;
7160 
7161 	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
7162 		values[n++] = enabled;
7163 
7164 	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
7165 		values[n++] = running;
7166 
7167 	if ((leader != event) &&
7168 	    (leader->state == PERF_EVENT_STATE_ACTIVE))
7169 		leader->pmu->read(leader);
7170 
7171 	values[n++] = perf_event_count(leader);
7172 	if (read_format & PERF_FORMAT_ID)
7173 		values[n++] = primary_event_id(leader);
7174 	if (read_format & PERF_FORMAT_LOST)
7175 		values[n++] = atomic64_read(&leader->lost_samples);
7176 
7177 	__output_copy(handle, values, n * sizeof(u64));
7178 
7179 	for_each_sibling_event(sub, leader) {
7180 		n = 0;
7181 
7182 		if ((sub != event) &&
7183 		    (sub->state == PERF_EVENT_STATE_ACTIVE))
7184 			sub->pmu->read(sub);
7185 
7186 		values[n++] = perf_event_count(sub);
7187 		if (read_format & PERF_FORMAT_ID)
7188 			values[n++] = primary_event_id(sub);
7189 		if (read_format & PERF_FORMAT_LOST)
7190 			values[n++] = atomic64_read(&sub->lost_samples);
7191 
7192 		__output_copy(handle, values, n * sizeof(u64));
7193 	}
7194 
7195 	local_irq_restore(flags);
7196 }
7197 
7198 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
7199 				 PERF_FORMAT_TOTAL_TIME_RUNNING)
7200 
7201 /*
7202  * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
7203  *
7204  * The problem is that its both hard and excessively expensive to iterate the
7205  * child list, not to mention that its impossible to IPI the children running
7206  * on another CPU, from interrupt/NMI context.
7207  */
7208 static void perf_output_read(struct perf_output_handle *handle,
7209 			     struct perf_event *event)
7210 {
7211 	u64 enabled = 0, running = 0, now;
7212 	u64 read_format = event->attr.read_format;
7213 
7214 	/*
7215 	 * compute total_time_enabled, total_time_running
7216 	 * based on snapshot values taken when the event
7217 	 * was last scheduled in.
7218 	 *
7219 	 * we cannot simply called update_context_time()
7220 	 * because of locking issue as we are called in
7221 	 * NMI context
7222 	 */
7223 	if (read_format & PERF_FORMAT_TOTAL_TIMES)
7224 		calc_timer_values(event, &now, &enabled, &running);
7225 
7226 	if (event->attr.read_format & PERF_FORMAT_GROUP)
7227 		perf_output_read_group(handle, event, enabled, running);
7228 	else
7229 		perf_output_read_one(handle, event, enabled, running);
7230 }
7231 
7232 void perf_output_sample(struct perf_output_handle *handle,
7233 			struct perf_event_header *header,
7234 			struct perf_sample_data *data,
7235 			struct perf_event *event)
7236 {
7237 	u64 sample_type = data->type;
7238 
7239 	perf_output_put(handle, *header);
7240 
7241 	if (sample_type & PERF_SAMPLE_IDENTIFIER)
7242 		perf_output_put(handle, data->id);
7243 
7244 	if (sample_type & PERF_SAMPLE_IP)
7245 		perf_output_put(handle, data->ip);
7246 
7247 	if (sample_type & PERF_SAMPLE_TID)
7248 		perf_output_put(handle, data->tid_entry);
7249 
7250 	if (sample_type & PERF_SAMPLE_TIME)
7251 		perf_output_put(handle, data->time);
7252 
7253 	if (sample_type & PERF_SAMPLE_ADDR)
7254 		perf_output_put(handle, data->addr);
7255 
7256 	if (sample_type & PERF_SAMPLE_ID)
7257 		perf_output_put(handle, data->id);
7258 
7259 	if (sample_type & PERF_SAMPLE_STREAM_ID)
7260 		perf_output_put(handle, data->stream_id);
7261 
7262 	if (sample_type & PERF_SAMPLE_CPU)
7263 		perf_output_put(handle, data->cpu_entry);
7264 
7265 	if (sample_type & PERF_SAMPLE_PERIOD)
7266 		perf_output_put(handle, data->period);
7267 
7268 	if (sample_type & PERF_SAMPLE_READ)
7269 		perf_output_read(handle, event);
7270 
7271 	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
7272 		int size = 1;
7273 
7274 		size += data->callchain->nr;
7275 		size *= sizeof(u64);
7276 		__output_copy(handle, data->callchain, size);
7277 	}
7278 
7279 	if (sample_type & PERF_SAMPLE_RAW) {
7280 		struct perf_raw_record *raw = data->raw;
7281 
7282 		if (raw) {
7283 			struct perf_raw_frag *frag = &raw->frag;
7284 
7285 			perf_output_put(handle, raw->size);
7286 			do {
7287 				if (frag->copy) {
7288 					__output_custom(handle, frag->copy,
7289 							frag->data, frag->size);
7290 				} else {
7291 					__output_copy(handle, frag->data,
7292 						      frag->size);
7293 				}
7294 				if (perf_raw_frag_last(frag))
7295 					break;
7296 				frag = frag->next;
7297 			} while (1);
7298 			if (frag->pad)
7299 				__output_skip(handle, NULL, frag->pad);
7300 		} else {
7301 			struct {
7302 				u32	size;
7303 				u32	data;
7304 			} raw = {
7305 				.size = sizeof(u32),
7306 				.data = 0,
7307 			};
7308 			perf_output_put(handle, raw);
7309 		}
7310 	}
7311 
7312 	if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7313 		if (data->sample_flags & PERF_SAMPLE_BRANCH_STACK) {
7314 			size_t size;
7315 
7316 			size = data->br_stack->nr
7317 			     * sizeof(struct perf_branch_entry);
7318 
7319 			perf_output_put(handle, data->br_stack->nr);
7320 			if (branch_sample_hw_index(event))
7321 				perf_output_put(handle, data->br_stack->hw_idx);
7322 			perf_output_copy(handle, data->br_stack->entries, size);
7323 		} else {
7324 			/*
7325 			 * we always store at least the value of nr
7326 			 */
7327 			u64 nr = 0;
7328 			perf_output_put(handle, nr);
7329 		}
7330 	}
7331 
7332 	if (sample_type & PERF_SAMPLE_REGS_USER) {
7333 		u64 abi = data->regs_user.abi;
7334 
7335 		/*
7336 		 * If there are no regs to dump, notice it through
7337 		 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7338 		 */
7339 		perf_output_put(handle, abi);
7340 
7341 		if (abi) {
7342 			u64 mask = event->attr.sample_regs_user;
7343 			perf_output_sample_regs(handle,
7344 						data->regs_user.regs,
7345 						mask);
7346 		}
7347 	}
7348 
7349 	if (sample_type & PERF_SAMPLE_STACK_USER) {
7350 		perf_output_sample_ustack(handle,
7351 					  data->stack_user_size,
7352 					  data->regs_user.regs);
7353 	}
7354 
7355 	if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
7356 		perf_output_put(handle, data->weight.full);
7357 
7358 	if (sample_type & PERF_SAMPLE_DATA_SRC)
7359 		perf_output_put(handle, data->data_src.val);
7360 
7361 	if (sample_type & PERF_SAMPLE_TRANSACTION)
7362 		perf_output_put(handle, data->txn);
7363 
7364 	if (sample_type & PERF_SAMPLE_REGS_INTR) {
7365 		u64 abi = data->regs_intr.abi;
7366 		/*
7367 		 * If there are no regs to dump, notice it through
7368 		 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7369 		 */
7370 		perf_output_put(handle, abi);
7371 
7372 		if (abi) {
7373 			u64 mask = event->attr.sample_regs_intr;
7374 
7375 			perf_output_sample_regs(handle,
7376 						data->regs_intr.regs,
7377 						mask);
7378 		}
7379 	}
7380 
7381 	if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7382 		perf_output_put(handle, data->phys_addr);
7383 
7384 	if (sample_type & PERF_SAMPLE_CGROUP)
7385 		perf_output_put(handle, data->cgroup);
7386 
7387 	if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7388 		perf_output_put(handle, data->data_page_size);
7389 
7390 	if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7391 		perf_output_put(handle, data->code_page_size);
7392 
7393 	if (sample_type & PERF_SAMPLE_AUX) {
7394 		perf_output_put(handle, data->aux_size);
7395 
7396 		if (data->aux_size)
7397 			perf_aux_sample_output(event, handle, data);
7398 	}
7399 
7400 	if (!event->attr.watermark) {
7401 		int wakeup_events = event->attr.wakeup_events;
7402 
7403 		if (wakeup_events) {
7404 			struct perf_buffer *rb = handle->rb;
7405 			int events = local_inc_return(&rb->events);
7406 
7407 			if (events >= wakeup_events) {
7408 				local_sub(wakeup_events, &rb->events);
7409 				local_inc(&rb->wakeup);
7410 			}
7411 		}
7412 	}
7413 }
7414 
7415 static u64 perf_virt_to_phys(u64 virt)
7416 {
7417 	u64 phys_addr = 0;
7418 
7419 	if (!virt)
7420 		return 0;
7421 
7422 	if (virt >= TASK_SIZE) {
7423 		/* If it's vmalloc()d memory, leave phys_addr as 0 */
7424 		if (virt_addr_valid((void *)(uintptr_t)virt) &&
7425 		    !(virt >= VMALLOC_START && virt < VMALLOC_END))
7426 			phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
7427 	} else {
7428 		/*
7429 		 * Walking the pages tables for user address.
7430 		 * Interrupts are disabled, so it prevents any tear down
7431 		 * of the page tables.
7432 		 * Try IRQ-safe get_user_page_fast_only first.
7433 		 * If failed, leave phys_addr as 0.
7434 		 */
7435 		if (current->mm != NULL) {
7436 			struct page *p;
7437 
7438 			pagefault_disable();
7439 			if (get_user_page_fast_only(virt, 0, &p)) {
7440 				phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
7441 				put_page(p);
7442 			}
7443 			pagefault_enable();
7444 		}
7445 	}
7446 
7447 	return phys_addr;
7448 }
7449 
7450 /*
7451  * Return the pagetable size of a given virtual address.
7452  */
7453 static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
7454 {
7455 	u64 size = 0;
7456 
7457 #ifdef CONFIG_HAVE_FAST_GUP
7458 	pgd_t *pgdp, pgd;
7459 	p4d_t *p4dp, p4d;
7460 	pud_t *pudp, pud;
7461 	pmd_t *pmdp, pmd;
7462 	pte_t *ptep, pte;
7463 
7464 	pgdp = pgd_offset(mm, addr);
7465 	pgd = READ_ONCE(*pgdp);
7466 	if (pgd_none(pgd))
7467 		return 0;
7468 
7469 	if (pgd_leaf(pgd))
7470 		return pgd_leaf_size(pgd);
7471 
7472 	p4dp = p4d_offset_lockless(pgdp, pgd, addr);
7473 	p4d = READ_ONCE(*p4dp);
7474 	if (!p4d_present(p4d))
7475 		return 0;
7476 
7477 	if (p4d_leaf(p4d))
7478 		return p4d_leaf_size(p4d);
7479 
7480 	pudp = pud_offset_lockless(p4dp, p4d, addr);
7481 	pud = READ_ONCE(*pudp);
7482 	if (!pud_present(pud))
7483 		return 0;
7484 
7485 	if (pud_leaf(pud))
7486 		return pud_leaf_size(pud);
7487 
7488 	pmdp = pmd_offset_lockless(pudp, pud, addr);
7489 	pmd = pmdp_get_lockless(pmdp);
7490 	if (!pmd_present(pmd))
7491 		return 0;
7492 
7493 	if (pmd_leaf(pmd))
7494 		return pmd_leaf_size(pmd);
7495 
7496 	ptep = pte_offset_map(&pmd, addr);
7497 	pte = ptep_get_lockless(ptep);
7498 	if (pte_present(pte))
7499 		size = pte_leaf_size(pte);
7500 	pte_unmap(ptep);
7501 #endif /* CONFIG_HAVE_FAST_GUP */
7502 
7503 	return size;
7504 }
7505 
7506 static u64 perf_get_page_size(unsigned long addr)
7507 {
7508 	struct mm_struct *mm;
7509 	unsigned long flags;
7510 	u64 size;
7511 
7512 	if (!addr)
7513 		return 0;
7514 
7515 	/*
7516 	 * Software page-table walkers must disable IRQs,
7517 	 * which prevents any tear down of the page tables.
7518 	 */
7519 	local_irq_save(flags);
7520 
7521 	mm = current->mm;
7522 	if (!mm) {
7523 		/*
7524 		 * For kernel threads and the like, use init_mm so that
7525 		 * we can find kernel memory.
7526 		 */
7527 		mm = &init_mm;
7528 	}
7529 
7530 	size = perf_get_pgtable_size(mm, addr);
7531 
7532 	local_irq_restore(flags);
7533 
7534 	return size;
7535 }
7536 
7537 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
7538 
7539 struct perf_callchain_entry *
7540 perf_callchain(struct perf_event *event, struct pt_regs *regs)
7541 {
7542 	bool kernel = !event->attr.exclude_callchain_kernel;
7543 	bool user   = !event->attr.exclude_callchain_user;
7544 	/* Disallow cross-task user callchains. */
7545 	bool crosstask = event->ctx->task && event->ctx->task != current;
7546 	const u32 max_stack = event->attr.sample_max_stack;
7547 	struct perf_callchain_entry *callchain;
7548 
7549 	if (!kernel && !user)
7550 		return &__empty_callchain;
7551 
7552 	callchain = get_perf_callchain(regs, 0, kernel, user,
7553 				       max_stack, crosstask, true);
7554 	return callchain ?: &__empty_callchain;
7555 }
7556 
7557 void perf_prepare_sample(struct perf_event_header *header,
7558 			 struct perf_sample_data *data,
7559 			 struct perf_event *event,
7560 			 struct pt_regs *regs)
7561 {
7562 	u64 sample_type = event->attr.sample_type;
7563 	u64 filtered_sample_type;
7564 
7565 	header->type = PERF_RECORD_SAMPLE;
7566 	header->size = sizeof(*header) + event->header_size;
7567 
7568 	header->misc = 0;
7569 	header->misc |= perf_misc_flags(regs);
7570 
7571 	/*
7572 	 * Clear the sample flags that have already been done by the
7573 	 * PMU driver.
7574 	 */
7575 	filtered_sample_type = sample_type & ~data->sample_flags;
7576 	__perf_event_header__init_id(header, data, event, filtered_sample_type);
7577 
7578 	if (sample_type & (PERF_SAMPLE_IP | PERF_SAMPLE_CODE_PAGE_SIZE))
7579 		data->ip = perf_instruction_pointer(regs);
7580 
7581 	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
7582 		int size = 1;
7583 
7584 		if (filtered_sample_type & PERF_SAMPLE_CALLCHAIN)
7585 			data->callchain = perf_callchain(event, regs);
7586 
7587 		size += data->callchain->nr;
7588 
7589 		header->size += size * sizeof(u64);
7590 	}
7591 
7592 	if (sample_type & PERF_SAMPLE_RAW) {
7593 		struct perf_raw_record *raw = data->raw;
7594 		int size;
7595 
7596 		if (raw && (data->sample_flags & PERF_SAMPLE_RAW)) {
7597 			struct perf_raw_frag *frag = &raw->frag;
7598 			u32 sum = 0;
7599 
7600 			do {
7601 				sum += frag->size;
7602 				if (perf_raw_frag_last(frag))
7603 					break;
7604 				frag = frag->next;
7605 			} while (1);
7606 
7607 			size = round_up(sum + sizeof(u32), sizeof(u64));
7608 			raw->size = size - sizeof(u32);
7609 			frag->pad = raw->size - sum;
7610 		} else {
7611 			size = sizeof(u64);
7612 			data->raw = NULL;
7613 		}
7614 
7615 		header->size += size;
7616 	}
7617 
7618 	if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7619 		int size = sizeof(u64); /* nr */
7620 		if (data->sample_flags & PERF_SAMPLE_BRANCH_STACK) {
7621 			if (branch_sample_hw_index(event))
7622 				size += sizeof(u64);
7623 
7624 			size += data->br_stack->nr
7625 			      * sizeof(struct perf_branch_entry);
7626 		}
7627 		header->size += size;
7628 	}
7629 
7630 	if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
7631 		perf_sample_regs_user(&data->regs_user, regs);
7632 
7633 	if (sample_type & PERF_SAMPLE_REGS_USER) {
7634 		/* regs dump ABI info */
7635 		int size = sizeof(u64);
7636 
7637 		if (data->regs_user.regs) {
7638 			u64 mask = event->attr.sample_regs_user;
7639 			size += hweight64(mask) * sizeof(u64);
7640 		}
7641 
7642 		header->size += size;
7643 	}
7644 
7645 	if (sample_type & PERF_SAMPLE_STACK_USER) {
7646 		/*
7647 		 * Either we need PERF_SAMPLE_STACK_USER bit to be always
7648 		 * processed as the last one or have additional check added
7649 		 * in case new sample type is added, because we could eat
7650 		 * up the rest of the sample size.
7651 		 */
7652 		u16 stack_size = event->attr.sample_stack_user;
7653 		u16 size = sizeof(u64);
7654 
7655 		stack_size = perf_sample_ustack_size(stack_size, header->size,
7656 						     data->regs_user.regs);
7657 
7658 		/*
7659 		 * If there is something to dump, add space for the dump
7660 		 * itself and for the field that tells the dynamic size,
7661 		 * which is how many have been actually dumped.
7662 		 */
7663 		if (stack_size)
7664 			size += sizeof(u64) + stack_size;
7665 
7666 		data->stack_user_size = stack_size;
7667 		header->size += size;
7668 	}
7669 
7670 	if (filtered_sample_type & PERF_SAMPLE_WEIGHT_TYPE)
7671 		data->weight.full = 0;
7672 
7673 	if (filtered_sample_type & PERF_SAMPLE_DATA_SRC)
7674 		data->data_src.val = PERF_MEM_NA;
7675 
7676 	if (filtered_sample_type & PERF_SAMPLE_TRANSACTION)
7677 		data->txn = 0;
7678 
7679 	if (sample_type & (PERF_SAMPLE_ADDR | PERF_SAMPLE_PHYS_ADDR | PERF_SAMPLE_DATA_PAGE_SIZE)) {
7680 		if (filtered_sample_type & PERF_SAMPLE_ADDR)
7681 			data->addr = 0;
7682 	}
7683 
7684 	if (sample_type & PERF_SAMPLE_REGS_INTR) {
7685 		/* regs dump ABI info */
7686 		int size = sizeof(u64);
7687 
7688 		perf_sample_regs_intr(&data->regs_intr, regs);
7689 
7690 		if (data->regs_intr.regs) {
7691 			u64 mask = event->attr.sample_regs_intr;
7692 
7693 			size += hweight64(mask) * sizeof(u64);
7694 		}
7695 
7696 		header->size += size;
7697 	}
7698 
7699 	if (sample_type & PERF_SAMPLE_PHYS_ADDR &&
7700 	    filtered_sample_type & PERF_SAMPLE_PHYS_ADDR)
7701 		data->phys_addr = perf_virt_to_phys(data->addr);
7702 
7703 #ifdef CONFIG_CGROUP_PERF
7704 	if (sample_type & PERF_SAMPLE_CGROUP) {
7705 		struct cgroup *cgrp;
7706 
7707 		/* protected by RCU */
7708 		cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup;
7709 		data->cgroup = cgroup_id(cgrp);
7710 	}
7711 #endif
7712 
7713 	/*
7714 	 * PERF_DATA_PAGE_SIZE requires PERF_SAMPLE_ADDR. If the user doesn't
7715 	 * require PERF_SAMPLE_ADDR, kernel implicitly retrieve the data->addr,
7716 	 * but the value will not dump to the userspace.
7717 	 */
7718 	if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7719 		data->data_page_size = perf_get_page_size(data->addr);
7720 
7721 	if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7722 		data->code_page_size = perf_get_page_size(data->ip);
7723 
7724 	if (sample_type & PERF_SAMPLE_AUX) {
7725 		u64 size;
7726 
7727 		header->size += sizeof(u64); /* size */
7728 
7729 		/*
7730 		 * Given the 16bit nature of header::size, an AUX sample can
7731 		 * easily overflow it, what with all the preceding sample bits.
7732 		 * Make sure this doesn't happen by using up to U16_MAX bytes
7733 		 * per sample in total (rounded down to 8 byte boundary).
7734 		 */
7735 		size = min_t(size_t, U16_MAX - header->size,
7736 			     event->attr.aux_sample_size);
7737 		size = rounddown(size, 8);
7738 		size = perf_prepare_sample_aux(event, data, size);
7739 
7740 		WARN_ON_ONCE(size + header->size > U16_MAX);
7741 		header->size += size;
7742 	}
7743 	/*
7744 	 * If you're adding more sample types here, you likely need to do
7745 	 * something about the overflowing header::size, like repurpose the
7746 	 * lowest 3 bits of size, which should be always zero at the moment.
7747 	 * This raises a more important question, do we really need 512k sized
7748 	 * samples and why, so good argumentation is in order for whatever you
7749 	 * do here next.
7750 	 */
7751 	WARN_ON_ONCE(header->size & 7);
7752 }
7753 
7754 static __always_inline int
7755 __perf_event_output(struct perf_event *event,
7756 		    struct perf_sample_data *data,
7757 		    struct pt_regs *regs,
7758 		    int (*output_begin)(struct perf_output_handle *,
7759 					struct perf_sample_data *,
7760 					struct perf_event *,
7761 					unsigned int))
7762 {
7763 	struct perf_output_handle handle;
7764 	struct perf_event_header header;
7765 	int err;
7766 
7767 	/* protect the callchain buffers */
7768 	rcu_read_lock();
7769 
7770 	perf_prepare_sample(&header, data, event, regs);
7771 
7772 	err = output_begin(&handle, data, event, header.size);
7773 	if (err)
7774 		goto exit;
7775 
7776 	perf_output_sample(&handle, &header, data, event);
7777 
7778 	perf_output_end(&handle);
7779 
7780 exit:
7781 	rcu_read_unlock();
7782 	return err;
7783 }
7784 
7785 void
7786 perf_event_output_forward(struct perf_event *event,
7787 			 struct perf_sample_data *data,
7788 			 struct pt_regs *regs)
7789 {
7790 	__perf_event_output(event, data, regs, perf_output_begin_forward);
7791 }
7792 
7793 void
7794 perf_event_output_backward(struct perf_event *event,
7795 			   struct perf_sample_data *data,
7796 			   struct pt_regs *regs)
7797 {
7798 	__perf_event_output(event, data, regs, perf_output_begin_backward);
7799 }
7800 
7801 int
7802 perf_event_output(struct perf_event *event,
7803 		  struct perf_sample_data *data,
7804 		  struct pt_regs *regs)
7805 {
7806 	return __perf_event_output(event, data, regs, perf_output_begin);
7807 }
7808 
7809 /*
7810  * read event_id
7811  */
7812 
7813 struct perf_read_event {
7814 	struct perf_event_header	header;
7815 
7816 	u32				pid;
7817 	u32				tid;
7818 };
7819 
7820 static void
7821 perf_event_read_event(struct perf_event *event,
7822 			struct task_struct *task)
7823 {
7824 	struct perf_output_handle handle;
7825 	struct perf_sample_data sample;
7826 	struct perf_read_event read_event = {
7827 		.header = {
7828 			.type = PERF_RECORD_READ,
7829 			.misc = 0,
7830 			.size = sizeof(read_event) + event->read_size,
7831 		},
7832 		.pid = perf_event_pid(event, task),
7833 		.tid = perf_event_tid(event, task),
7834 	};
7835 	int ret;
7836 
7837 	perf_event_header__init_id(&read_event.header, &sample, event);
7838 	ret = perf_output_begin(&handle, &sample, event, read_event.header.size);
7839 	if (ret)
7840 		return;
7841 
7842 	perf_output_put(&handle, read_event);
7843 	perf_output_read(&handle, event);
7844 	perf_event__output_id_sample(event, &handle, &sample);
7845 
7846 	perf_output_end(&handle);
7847 }
7848 
7849 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
7850 
7851 static void
7852 perf_iterate_ctx(struct perf_event_context *ctx,
7853 		   perf_iterate_f output,
7854 		   void *data, bool all)
7855 {
7856 	struct perf_event *event;
7857 
7858 	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7859 		if (!all) {
7860 			if (event->state < PERF_EVENT_STATE_INACTIVE)
7861 				continue;
7862 			if (!event_filter_match(event))
7863 				continue;
7864 		}
7865 
7866 		output(event, data);
7867 	}
7868 }
7869 
7870 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
7871 {
7872 	struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
7873 	struct perf_event *event;
7874 
7875 	list_for_each_entry_rcu(event, &pel->list, sb_list) {
7876 		/*
7877 		 * Skip events that are not fully formed yet; ensure that
7878 		 * if we observe event->ctx, both event and ctx will be
7879 		 * complete enough. See perf_install_in_context().
7880 		 */
7881 		if (!smp_load_acquire(&event->ctx))
7882 			continue;
7883 
7884 		if (event->state < PERF_EVENT_STATE_INACTIVE)
7885 			continue;
7886 		if (!event_filter_match(event))
7887 			continue;
7888 		output(event, data);
7889 	}
7890 }
7891 
7892 /*
7893  * Iterate all events that need to receive side-band events.
7894  *
7895  * For new callers; ensure that account_pmu_sb_event() includes
7896  * your event, otherwise it might not get delivered.
7897  */
7898 static void
7899 perf_iterate_sb(perf_iterate_f output, void *data,
7900 	       struct perf_event_context *task_ctx)
7901 {
7902 	struct perf_event_context *ctx;
7903 
7904 	rcu_read_lock();
7905 	preempt_disable();
7906 
7907 	/*
7908 	 * If we have task_ctx != NULL we only notify the task context itself.
7909 	 * The task_ctx is set only for EXIT events before releasing task
7910 	 * context.
7911 	 */
7912 	if (task_ctx) {
7913 		perf_iterate_ctx(task_ctx, output, data, false);
7914 		goto done;
7915 	}
7916 
7917 	perf_iterate_sb_cpu(output, data);
7918 
7919 	ctx = rcu_dereference(current->perf_event_ctxp);
7920 	if (ctx)
7921 		perf_iterate_ctx(ctx, output, data, false);
7922 done:
7923 	preempt_enable();
7924 	rcu_read_unlock();
7925 }
7926 
7927 /*
7928  * Clear all file-based filters at exec, they'll have to be
7929  * re-instated when/if these objects are mmapped again.
7930  */
7931 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
7932 {
7933 	struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7934 	struct perf_addr_filter *filter;
7935 	unsigned int restart = 0, count = 0;
7936 	unsigned long flags;
7937 
7938 	if (!has_addr_filter(event))
7939 		return;
7940 
7941 	raw_spin_lock_irqsave(&ifh->lock, flags);
7942 	list_for_each_entry(filter, &ifh->list, entry) {
7943 		if (filter->path.dentry) {
7944 			event->addr_filter_ranges[count].start = 0;
7945 			event->addr_filter_ranges[count].size = 0;
7946 			restart++;
7947 		}
7948 
7949 		count++;
7950 	}
7951 
7952 	if (restart)
7953 		event->addr_filters_gen++;
7954 	raw_spin_unlock_irqrestore(&ifh->lock, flags);
7955 
7956 	if (restart)
7957 		perf_event_stop(event, 1);
7958 }
7959 
7960 void perf_event_exec(void)
7961 {
7962 	struct perf_event_context *ctx;
7963 
7964 	ctx = perf_pin_task_context(current);
7965 	if (!ctx)
7966 		return;
7967 
7968 	perf_event_enable_on_exec(ctx);
7969 	perf_event_remove_on_exec(ctx);
7970 	perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL, true);
7971 
7972 	perf_unpin_context(ctx);
7973 	put_ctx(ctx);
7974 }
7975 
7976 struct remote_output {
7977 	struct perf_buffer	*rb;
7978 	int			err;
7979 };
7980 
7981 static void __perf_event_output_stop(struct perf_event *event, void *data)
7982 {
7983 	struct perf_event *parent = event->parent;
7984 	struct remote_output *ro = data;
7985 	struct perf_buffer *rb = ro->rb;
7986 	struct stop_event_data sd = {
7987 		.event	= event,
7988 	};
7989 
7990 	if (!has_aux(event))
7991 		return;
7992 
7993 	if (!parent)
7994 		parent = event;
7995 
7996 	/*
7997 	 * In case of inheritance, it will be the parent that links to the
7998 	 * ring-buffer, but it will be the child that's actually using it.
7999 	 *
8000 	 * We are using event::rb to determine if the event should be stopped,
8001 	 * however this may race with ring_buffer_attach() (through set_output),
8002 	 * which will make us skip the event that actually needs to be stopped.
8003 	 * So ring_buffer_attach() has to stop an aux event before re-assigning
8004 	 * its rb pointer.
8005 	 */
8006 	if (rcu_dereference(parent->rb) == rb)
8007 		ro->err = __perf_event_stop(&sd);
8008 }
8009 
8010 static int __perf_pmu_output_stop(void *info)
8011 {
8012 	struct perf_event *event = info;
8013 	struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
8014 	struct remote_output ro = {
8015 		.rb	= event->rb,
8016 	};
8017 
8018 	rcu_read_lock();
8019 	perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
8020 	if (cpuctx->task_ctx)
8021 		perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
8022 				   &ro, false);
8023 	rcu_read_unlock();
8024 
8025 	return ro.err;
8026 }
8027 
8028 static void perf_pmu_output_stop(struct perf_event *event)
8029 {
8030 	struct perf_event *iter;
8031 	int err, cpu;
8032 
8033 restart:
8034 	rcu_read_lock();
8035 	list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
8036 		/*
8037 		 * For per-CPU events, we need to make sure that neither they
8038 		 * nor their children are running; for cpu==-1 events it's
8039 		 * sufficient to stop the event itself if it's active, since
8040 		 * it can't have children.
8041 		 */
8042 		cpu = iter->cpu;
8043 		if (cpu == -1)
8044 			cpu = READ_ONCE(iter->oncpu);
8045 
8046 		if (cpu == -1)
8047 			continue;
8048 
8049 		err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
8050 		if (err == -EAGAIN) {
8051 			rcu_read_unlock();
8052 			goto restart;
8053 		}
8054 	}
8055 	rcu_read_unlock();
8056 }
8057 
8058 /*
8059  * task tracking -- fork/exit
8060  *
8061  * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
8062  */
8063 
8064 struct perf_task_event {
8065 	struct task_struct		*task;
8066 	struct perf_event_context	*task_ctx;
8067 
8068 	struct {
8069 		struct perf_event_header	header;
8070 
8071 		u32				pid;
8072 		u32				ppid;
8073 		u32				tid;
8074 		u32				ptid;
8075 		u64				time;
8076 	} event_id;
8077 };
8078 
8079 static int perf_event_task_match(struct perf_event *event)
8080 {
8081 	return event->attr.comm  || event->attr.mmap ||
8082 	       event->attr.mmap2 || event->attr.mmap_data ||
8083 	       event->attr.task;
8084 }
8085 
8086 static void perf_event_task_output(struct perf_event *event,
8087 				   void *data)
8088 {
8089 	struct perf_task_event *task_event = data;
8090 	struct perf_output_handle handle;
8091 	struct perf_sample_data	sample;
8092 	struct task_struct *task = task_event->task;
8093 	int ret, size = task_event->event_id.header.size;
8094 
8095 	if (!perf_event_task_match(event))
8096 		return;
8097 
8098 	perf_event_header__init_id(&task_event->event_id.header, &sample, event);
8099 
8100 	ret = perf_output_begin(&handle, &sample, event,
8101 				task_event->event_id.header.size);
8102 	if (ret)
8103 		goto out;
8104 
8105 	task_event->event_id.pid = perf_event_pid(event, task);
8106 	task_event->event_id.tid = perf_event_tid(event, task);
8107 
8108 	if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
8109 		task_event->event_id.ppid = perf_event_pid(event,
8110 							task->real_parent);
8111 		task_event->event_id.ptid = perf_event_pid(event,
8112 							task->real_parent);
8113 	} else {  /* PERF_RECORD_FORK */
8114 		task_event->event_id.ppid = perf_event_pid(event, current);
8115 		task_event->event_id.ptid = perf_event_tid(event, current);
8116 	}
8117 
8118 	task_event->event_id.time = perf_event_clock(event);
8119 
8120 	perf_output_put(&handle, task_event->event_id);
8121 
8122 	perf_event__output_id_sample(event, &handle, &sample);
8123 
8124 	perf_output_end(&handle);
8125 out:
8126 	task_event->event_id.header.size = size;
8127 }
8128 
8129 static void perf_event_task(struct task_struct *task,
8130 			      struct perf_event_context *task_ctx,
8131 			      int new)
8132 {
8133 	struct perf_task_event task_event;
8134 
8135 	if (!atomic_read(&nr_comm_events) &&
8136 	    !atomic_read(&nr_mmap_events) &&
8137 	    !atomic_read(&nr_task_events))
8138 		return;
8139 
8140 	task_event = (struct perf_task_event){
8141 		.task	  = task,
8142 		.task_ctx = task_ctx,
8143 		.event_id    = {
8144 			.header = {
8145 				.type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
8146 				.misc = 0,
8147 				.size = sizeof(task_event.event_id),
8148 			},
8149 			/* .pid  */
8150 			/* .ppid */
8151 			/* .tid  */
8152 			/* .ptid */
8153 			/* .time */
8154 		},
8155 	};
8156 
8157 	perf_iterate_sb(perf_event_task_output,
8158 		       &task_event,
8159 		       task_ctx);
8160 }
8161 
8162 void perf_event_fork(struct task_struct *task)
8163 {
8164 	perf_event_task(task, NULL, 1);
8165 	perf_event_namespaces(task);
8166 }
8167 
8168 /*
8169  * comm tracking
8170  */
8171 
8172 struct perf_comm_event {
8173 	struct task_struct	*task;
8174 	char			*comm;
8175 	int			comm_size;
8176 
8177 	struct {
8178 		struct perf_event_header	header;
8179 
8180 		u32				pid;
8181 		u32				tid;
8182 	} event_id;
8183 };
8184 
8185 static int perf_event_comm_match(struct perf_event *event)
8186 {
8187 	return event->attr.comm;
8188 }
8189 
8190 static void perf_event_comm_output(struct perf_event *event,
8191 				   void *data)
8192 {
8193 	struct perf_comm_event *comm_event = data;
8194 	struct perf_output_handle handle;
8195 	struct perf_sample_data sample;
8196 	int size = comm_event->event_id.header.size;
8197 	int ret;
8198 
8199 	if (!perf_event_comm_match(event))
8200 		return;
8201 
8202 	perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
8203 	ret = perf_output_begin(&handle, &sample, event,
8204 				comm_event->event_id.header.size);
8205 
8206 	if (ret)
8207 		goto out;
8208 
8209 	comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
8210 	comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
8211 
8212 	perf_output_put(&handle, comm_event->event_id);
8213 	__output_copy(&handle, comm_event->comm,
8214 				   comm_event->comm_size);
8215 
8216 	perf_event__output_id_sample(event, &handle, &sample);
8217 
8218 	perf_output_end(&handle);
8219 out:
8220 	comm_event->event_id.header.size = size;
8221 }
8222 
8223 static void perf_event_comm_event(struct perf_comm_event *comm_event)
8224 {
8225 	char comm[TASK_COMM_LEN];
8226 	unsigned int size;
8227 
8228 	memset(comm, 0, sizeof(comm));
8229 	strlcpy(comm, comm_event->task->comm, sizeof(comm));
8230 	size = ALIGN(strlen(comm)+1, sizeof(u64));
8231 
8232 	comm_event->comm = comm;
8233 	comm_event->comm_size = size;
8234 
8235 	comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
8236 
8237 	perf_iterate_sb(perf_event_comm_output,
8238 		       comm_event,
8239 		       NULL);
8240 }
8241 
8242 void perf_event_comm(struct task_struct *task, bool exec)
8243 {
8244 	struct perf_comm_event comm_event;
8245 
8246 	if (!atomic_read(&nr_comm_events))
8247 		return;
8248 
8249 	comm_event = (struct perf_comm_event){
8250 		.task	= task,
8251 		/* .comm      */
8252 		/* .comm_size */
8253 		.event_id  = {
8254 			.header = {
8255 				.type = PERF_RECORD_COMM,
8256 				.misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
8257 				/* .size */
8258 			},
8259 			/* .pid */
8260 			/* .tid */
8261 		},
8262 	};
8263 
8264 	perf_event_comm_event(&comm_event);
8265 }
8266 
8267 /*
8268  * namespaces tracking
8269  */
8270 
8271 struct perf_namespaces_event {
8272 	struct task_struct		*task;
8273 
8274 	struct {
8275 		struct perf_event_header	header;
8276 
8277 		u32				pid;
8278 		u32				tid;
8279 		u64				nr_namespaces;
8280 		struct perf_ns_link_info	link_info[NR_NAMESPACES];
8281 	} event_id;
8282 };
8283 
8284 static int perf_event_namespaces_match(struct perf_event *event)
8285 {
8286 	return event->attr.namespaces;
8287 }
8288 
8289 static void perf_event_namespaces_output(struct perf_event *event,
8290 					 void *data)
8291 {
8292 	struct perf_namespaces_event *namespaces_event = data;
8293 	struct perf_output_handle handle;
8294 	struct perf_sample_data sample;
8295 	u16 header_size = namespaces_event->event_id.header.size;
8296 	int ret;
8297 
8298 	if (!perf_event_namespaces_match(event))
8299 		return;
8300 
8301 	perf_event_header__init_id(&namespaces_event->event_id.header,
8302 				   &sample, event);
8303 	ret = perf_output_begin(&handle, &sample, event,
8304 				namespaces_event->event_id.header.size);
8305 	if (ret)
8306 		goto out;
8307 
8308 	namespaces_event->event_id.pid = perf_event_pid(event,
8309 							namespaces_event->task);
8310 	namespaces_event->event_id.tid = perf_event_tid(event,
8311 							namespaces_event->task);
8312 
8313 	perf_output_put(&handle, namespaces_event->event_id);
8314 
8315 	perf_event__output_id_sample(event, &handle, &sample);
8316 
8317 	perf_output_end(&handle);
8318 out:
8319 	namespaces_event->event_id.header.size = header_size;
8320 }
8321 
8322 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
8323 				   struct task_struct *task,
8324 				   const struct proc_ns_operations *ns_ops)
8325 {
8326 	struct path ns_path;
8327 	struct inode *ns_inode;
8328 	int error;
8329 
8330 	error = ns_get_path(&ns_path, task, ns_ops);
8331 	if (!error) {
8332 		ns_inode = ns_path.dentry->d_inode;
8333 		ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
8334 		ns_link_info->ino = ns_inode->i_ino;
8335 		path_put(&ns_path);
8336 	}
8337 }
8338 
8339 void perf_event_namespaces(struct task_struct *task)
8340 {
8341 	struct perf_namespaces_event namespaces_event;
8342 	struct perf_ns_link_info *ns_link_info;
8343 
8344 	if (!atomic_read(&nr_namespaces_events))
8345 		return;
8346 
8347 	namespaces_event = (struct perf_namespaces_event){
8348 		.task	= task,
8349 		.event_id  = {
8350 			.header = {
8351 				.type = PERF_RECORD_NAMESPACES,
8352 				.misc = 0,
8353 				.size = sizeof(namespaces_event.event_id),
8354 			},
8355 			/* .pid */
8356 			/* .tid */
8357 			.nr_namespaces = NR_NAMESPACES,
8358 			/* .link_info[NR_NAMESPACES] */
8359 		},
8360 	};
8361 
8362 	ns_link_info = namespaces_event.event_id.link_info;
8363 
8364 	perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
8365 			       task, &mntns_operations);
8366 
8367 #ifdef CONFIG_USER_NS
8368 	perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
8369 			       task, &userns_operations);
8370 #endif
8371 #ifdef CONFIG_NET_NS
8372 	perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
8373 			       task, &netns_operations);
8374 #endif
8375 #ifdef CONFIG_UTS_NS
8376 	perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
8377 			       task, &utsns_operations);
8378 #endif
8379 #ifdef CONFIG_IPC_NS
8380 	perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
8381 			       task, &ipcns_operations);
8382 #endif
8383 #ifdef CONFIG_PID_NS
8384 	perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
8385 			       task, &pidns_operations);
8386 #endif
8387 #ifdef CONFIG_CGROUPS
8388 	perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
8389 			       task, &cgroupns_operations);
8390 #endif
8391 
8392 	perf_iterate_sb(perf_event_namespaces_output,
8393 			&namespaces_event,
8394 			NULL);
8395 }
8396 
8397 /*
8398  * cgroup tracking
8399  */
8400 #ifdef CONFIG_CGROUP_PERF
8401 
8402 struct perf_cgroup_event {
8403 	char				*path;
8404 	int				path_size;
8405 	struct {
8406 		struct perf_event_header	header;
8407 		u64				id;
8408 		char				path[];
8409 	} event_id;
8410 };
8411 
8412 static int perf_event_cgroup_match(struct perf_event *event)
8413 {
8414 	return event->attr.cgroup;
8415 }
8416 
8417 static void perf_event_cgroup_output(struct perf_event *event, void *data)
8418 {
8419 	struct perf_cgroup_event *cgroup_event = data;
8420 	struct perf_output_handle handle;
8421 	struct perf_sample_data sample;
8422 	u16 header_size = cgroup_event->event_id.header.size;
8423 	int ret;
8424 
8425 	if (!perf_event_cgroup_match(event))
8426 		return;
8427 
8428 	perf_event_header__init_id(&cgroup_event->event_id.header,
8429 				   &sample, event);
8430 	ret = perf_output_begin(&handle, &sample, event,
8431 				cgroup_event->event_id.header.size);
8432 	if (ret)
8433 		goto out;
8434 
8435 	perf_output_put(&handle, cgroup_event->event_id);
8436 	__output_copy(&handle, cgroup_event->path, cgroup_event->path_size);
8437 
8438 	perf_event__output_id_sample(event, &handle, &sample);
8439 
8440 	perf_output_end(&handle);
8441 out:
8442 	cgroup_event->event_id.header.size = header_size;
8443 }
8444 
8445 static void perf_event_cgroup(struct cgroup *cgrp)
8446 {
8447 	struct perf_cgroup_event cgroup_event;
8448 	char path_enomem[16] = "//enomem";
8449 	char *pathname;
8450 	size_t size;
8451 
8452 	if (!atomic_read(&nr_cgroup_events))
8453 		return;
8454 
8455 	cgroup_event = (struct perf_cgroup_event){
8456 		.event_id  = {
8457 			.header = {
8458 				.type = PERF_RECORD_CGROUP,
8459 				.misc = 0,
8460 				.size = sizeof(cgroup_event.event_id),
8461 			},
8462 			.id = cgroup_id(cgrp),
8463 		},
8464 	};
8465 
8466 	pathname = kmalloc(PATH_MAX, GFP_KERNEL);
8467 	if (pathname == NULL) {
8468 		cgroup_event.path = path_enomem;
8469 	} else {
8470 		/* just to be sure to have enough space for alignment */
8471 		cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64));
8472 		cgroup_event.path = pathname;
8473 	}
8474 
8475 	/*
8476 	 * Since our buffer works in 8 byte units we need to align our string
8477 	 * size to a multiple of 8. However, we must guarantee the tail end is
8478 	 * zero'd out to avoid leaking random bits to userspace.
8479 	 */
8480 	size = strlen(cgroup_event.path) + 1;
8481 	while (!IS_ALIGNED(size, sizeof(u64)))
8482 		cgroup_event.path[size++] = '\0';
8483 
8484 	cgroup_event.event_id.header.size += size;
8485 	cgroup_event.path_size = size;
8486 
8487 	perf_iterate_sb(perf_event_cgroup_output,
8488 			&cgroup_event,
8489 			NULL);
8490 
8491 	kfree(pathname);
8492 }
8493 
8494 #endif
8495 
8496 /*
8497  * mmap tracking
8498  */
8499 
8500 struct perf_mmap_event {
8501 	struct vm_area_struct	*vma;
8502 
8503 	const char		*file_name;
8504 	int			file_size;
8505 	int			maj, min;
8506 	u64			ino;
8507 	u64			ino_generation;
8508 	u32			prot, flags;
8509 	u8			build_id[BUILD_ID_SIZE_MAX];
8510 	u32			build_id_size;
8511 
8512 	struct {
8513 		struct perf_event_header	header;
8514 
8515 		u32				pid;
8516 		u32				tid;
8517 		u64				start;
8518 		u64				len;
8519 		u64				pgoff;
8520 	} event_id;
8521 };
8522 
8523 static int perf_event_mmap_match(struct perf_event *event,
8524 				 void *data)
8525 {
8526 	struct perf_mmap_event *mmap_event = data;
8527 	struct vm_area_struct *vma = mmap_event->vma;
8528 	int executable = vma->vm_flags & VM_EXEC;
8529 
8530 	return (!executable && event->attr.mmap_data) ||
8531 	       (executable && (event->attr.mmap || event->attr.mmap2));
8532 }
8533 
8534 static void perf_event_mmap_output(struct perf_event *event,
8535 				   void *data)
8536 {
8537 	struct perf_mmap_event *mmap_event = data;
8538 	struct perf_output_handle handle;
8539 	struct perf_sample_data sample;
8540 	int size = mmap_event->event_id.header.size;
8541 	u32 type = mmap_event->event_id.header.type;
8542 	bool use_build_id;
8543 	int ret;
8544 
8545 	if (!perf_event_mmap_match(event, data))
8546 		return;
8547 
8548 	if (event->attr.mmap2) {
8549 		mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
8550 		mmap_event->event_id.header.size += sizeof(mmap_event->maj);
8551 		mmap_event->event_id.header.size += sizeof(mmap_event->min);
8552 		mmap_event->event_id.header.size += sizeof(mmap_event->ino);
8553 		mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
8554 		mmap_event->event_id.header.size += sizeof(mmap_event->prot);
8555 		mmap_event->event_id.header.size += sizeof(mmap_event->flags);
8556 	}
8557 
8558 	perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
8559 	ret = perf_output_begin(&handle, &sample, event,
8560 				mmap_event->event_id.header.size);
8561 	if (ret)
8562 		goto out;
8563 
8564 	mmap_event->event_id.pid = perf_event_pid(event, current);
8565 	mmap_event->event_id.tid = perf_event_tid(event, current);
8566 
8567 	use_build_id = event->attr.build_id && mmap_event->build_id_size;
8568 
8569 	if (event->attr.mmap2 && use_build_id)
8570 		mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID;
8571 
8572 	perf_output_put(&handle, mmap_event->event_id);
8573 
8574 	if (event->attr.mmap2) {
8575 		if (use_build_id) {
8576 			u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 };
8577 
8578 			__output_copy(&handle, size, 4);
8579 			__output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE_MAX);
8580 		} else {
8581 			perf_output_put(&handle, mmap_event->maj);
8582 			perf_output_put(&handle, mmap_event->min);
8583 			perf_output_put(&handle, mmap_event->ino);
8584 			perf_output_put(&handle, mmap_event->ino_generation);
8585 		}
8586 		perf_output_put(&handle, mmap_event->prot);
8587 		perf_output_put(&handle, mmap_event->flags);
8588 	}
8589 
8590 	__output_copy(&handle, mmap_event->file_name,
8591 				   mmap_event->file_size);
8592 
8593 	perf_event__output_id_sample(event, &handle, &sample);
8594 
8595 	perf_output_end(&handle);
8596 out:
8597 	mmap_event->event_id.header.size = size;
8598 	mmap_event->event_id.header.type = type;
8599 }
8600 
8601 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
8602 {
8603 	struct vm_area_struct *vma = mmap_event->vma;
8604 	struct file *file = vma->vm_file;
8605 	int maj = 0, min = 0;
8606 	u64 ino = 0, gen = 0;
8607 	u32 prot = 0, flags = 0;
8608 	unsigned int size;
8609 	char tmp[16];
8610 	char *buf = NULL;
8611 	char *name;
8612 
8613 	if (vma->vm_flags & VM_READ)
8614 		prot |= PROT_READ;
8615 	if (vma->vm_flags & VM_WRITE)
8616 		prot |= PROT_WRITE;
8617 	if (vma->vm_flags & VM_EXEC)
8618 		prot |= PROT_EXEC;
8619 
8620 	if (vma->vm_flags & VM_MAYSHARE)
8621 		flags = MAP_SHARED;
8622 	else
8623 		flags = MAP_PRIVATE;
8624 
8625 	if (vma->vm_flags & VM_LOCKED)
8626 		flags |= MAP_LOCKED;
8627 	if (is_vm_hugetlb_page(vma))
8628 		flags |= MAP_HUGETLB;
8629 
8630 	if (file) {
8631 		struct inode *inode;
8632 		dev_t dev;
8633 
8634 		buf = kmalloc(PATH_MAX, GFP_KERNEL);
8635 		if (!buf) {
8636 			name = "//enomem";
8637 			goto cpy_name;
8638 		}
8639 		/*
8640 		 * d_path() works from the end of the rb backwards, so we
8641 		 * need to add enough zero bytes after the string to handle
8642 		 * the 64bit alignment we do later.
8643 		 */
8644 		name = file_path(file, buf, PATH_MAX - sizeof(u64));
8645 		if (IS_ERR(name)) {
8646 			name = "//toolong";
8647 			goto cpy_name;
8648 		}
8649 		inode = file_inode(vma->vm_file);
8650 		dev = inode->i_sb->s_dev;
8651 		ino = inode->i_ino;
8652 		gen = inode->i_generation;
8653 		maj = MAJOR(dev);
8654 		min = MINOR(dev);
8655 
8656 		goto got_name;
8657 	} else {
8658 		if (vma->vm_ops && vma->vm_ops->name) {
8659 			name = (char *) vma->vm_ops->name(vma);
8660 			if (name)
8661 				goto cpy_name;
8662 		}
8663 
8664 		name = (char *)arch_vma_name(vma);
8665 		if (name)
8666 			goto cpy_name;
8667 
8668 		if (vma->vm_start <= vma->vm_mm->start_brk &&
8669 				vma->vm_end >= vma->vm_mm->brk) {
8670 			name = "[heap]";
8671 			goto cpy_name;
8672 		}
8673 		if (vma->vm_start <= vma->vm_mm->start_stack &&
8674 				vma->vm_end >= vma->vm_mm->start_stack) {
8675 			name = "[stack]";
8676 			goto cpy_name;
8677 		}
8678 
8679 		name = "//anon";
8680 		goto cpy_name;
8681 	}
8682 
8683 cpy_name:
8684 	strlcpy(tmp, name, sizeof(tmp));
8685 	name = tmp;
8686 got_name:
8687 	/*
8688 	 * Since our buffer works in 8 byte units we need to align our string
8689 	 * size to a multiple of 8. However, we must guarantee the tail end is
8690 	 * zero'd out to avoid leaking random bits to userspace.
8691 	 */
8692 	size = strlen(name)+1;
8693 	while (!IS_ALIGNED(size, sizeof(u64)))
8694 		name[size++] = '\0';
8695 
8696 	mmap_event->file_name = name;
8697 	mmap_event->file_size = size;
8698 	mmap_event->maj = maj;
8699 	mmap_event->min = min;
8700 	mmap_event->ino = ino;
8701 	mmap_event->ino_generation = gen;
8702 	mmap_event->prot = prot;
8703 	mmap_event->flags = flags;
8704 
8705 	if (!(vma->vm_flags & VM_EXEC))
8706 		mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
8707 
8708 	mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
8709 
8710 	if (atomic_read(&nr_build_id_events))
8711 		build_id_parse(vma, mmap_event->build_id, &mmap_event->build_id_size);
8712 
8713 	perf_iterate_sb(perf_event_mmap_output,
8714 		       mmap_event,
8715 		       NULL);
8716 
8717 	kfree(buf);
8718 }
8719 
8720 /*
8721  * Check whether inode and address range match filter criteria.
8722  */
8723 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
8724 				     struct file *file, unsigned long offset,
8725 				     unsigned long size)
8726 {
8727 	/* d_inode(NULL) won't be equal to any mapped user-space file */
8728 	if (!filter->path.dentry)
8729 		return false;
8730 
8731 	if (d_inode(filter->path.dentry) != file_inode(file))
8732 		return false;
8733 
8734 	if (filter->offset > offset + size)
8735 		return false;
8736 
8737 	if (filter->offset + filter->size < offset)
8738 		return false;
8739 
8740 	return true;
8741 }
8742 
8743 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
8744 					struct vm_area_struct *vma,
8745 					struct perf_addr_filter_range *fr)
8746 {
8747 	unsigned long vma_size = vma->vm_end - vma->vm_start;
8748 	unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8749 	struct file *file = vma->vm_file;
8750 
8751 	if (!perf_addr_filter_match(filter, file, off, vma_size))
8752 		return false;
8753 
8754 	if (filter->offset < off) {
8755 		fr->start = vma->vm_start;
8756 		fr->size = min(vma_size, filter->size - (off - filter->offset));
8757 	} else {
8758 		fr->start = vma->vm_start + filter->offset - off;
8759 		fr->size = min(vma->vm_end - fr->start, filter->size);
8760 	}
8761 
8762 	return true;
8763 }
8764 
8765 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
8766 {
8767 	struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8768 	struct vm_area_struct *vma = data;
8769 	struct perf_addr_filter *filter;
8770 	unsigned int restart = 0, count = 0;
8771 	unsigned long flags;
8772 
8773 	if (!has_addr_filter(event))
8774 		return;
8775 
8776 	if (!vma->vm_file)
8777 		return;
8778 
8779 	raw_spin_lock_irqsave(&ifh->lock, flags);
8780 	list_for_each_entry(filter, &ifh->list, entry) {
8781 		if (perf_addr_filter_vma_adjust(filter, vma,
8782 						&event->addr_filter_ranges[count]))
8783 			restart++;
8784 
8785 		count++;
8786 	}
8787 
8788 	if (restart)
8789 		event->addr_filters_gen++;
8790 	raw_spin_unlock_irqrestore(&ifh->lock, flags);
8791 
8792 	if (restart)
8793 		perf_event_stop(event, 1);
8794 }
8795 
8796 /*
8797  * Adjust all task's events' filters to the new vma
8798  */
8799 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
8800 {
8801 	struct perf_event_context *ctx;
8802 
8803 	/*
8804 	 * Data tracing isn't supported yet and as such there is no need
8805 	 * to keep track of anything that isn't related to executable code:
8806 	 */
8807 	if (!(vma->vm_flags & VM_EXEC))
8808 		return;
8809 
8810 	rcu_read_lock();
8811 	ctx = rcu_dereference(current->perf_event_ctxp);
8812 	if (ctx)
8813 		perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
8814 	rcu_read_unlock();
8815 }
8816 
8817 void perf_event_mmap(struct vm_area_struct *vma)
8818 {
8819 	struct perf_mmap_event mmap_event;
8820 
8821 	if (!atomic_read(&nr_mmap_events))
8822 		return;
8823 
8824 	mmap_event = (struct perf_mmap_event){
8825 		.vma	= vma,
8826 		/* .file_name */
8827 		/* .file_size */
8828 		.event_id  = {
8829 			.header = {
8830 				.type = PERF_RECORD_MMAP,
8831 				.misc = PERF_RECORD_MISC_USER,
8832 				/* .size */
8833 			},
8834 			/* .pid */
8835 			/* .tid */
8836 			.start  = vma->vm_start,
8837 			.len    = vma->vm_end - vma->vm_start,
8838 			.pgoff  = (u64)vma->vm_pgoff << PAGE_SHIFT,
8839 		},
8840 		/* .maj (attr_mmap2 only) */
8841 		/* .min (attr_mmap2 only) */
8842 		/* .ino (attr_mmap2 only) */
8843 		/* .ino_generation (attr_mmap2 only) */
8844 		/* .prot (attr_mmap2 only) */
8845 		/* .flags (attr_mmap2 only) */
8846 	};
8847 
8848 	perf_addr_filters_adjust(vma);
8849 	perf_event_mmap_event(&mmap_event);
8850 }
8851 
8852 void perf_event_aux_event(struct perf_event *event, unsigned long head,
8853 			  unsigned long size, u64 flags)
8854 {
8855 	struct perf_output_handle handle;
8856 	struct perf_sample_data sample;
8857 	struct perf_aux_event {
8858 		struct perf_event_header	header;
8859 		u64				offset;
8860 		u64				size;
8861 		u64				flags;
8862 	} rec = {
8863 		.header = {
8864 			.type = PERF_RECORD_AUX,
8865 			.misc = 0,
8866 			.size = sizeof(rec),
8867 		},
8868 		.offset		= head,
8869 		.size		= size,
8870 		.flags		= flags,
8871 	};
8872 	int ret;
8873 
8874 	perf_event_header__init_id(&rec.header, &sample, event);
8875 	ret = perf_output_begin(&handle, &sample, event, rec.header.size);
8876 
8877 	if (ret)
8878 		return;
8879 
8880 	perf_output_put(&handle, rec);
8881 	perf_event__output_id_sample(event, &handle, &sample);
8882 
8883 	perf_output_end(&handle);
8884 }
8885 
8886 /*
8887  * Lost/dropped samples logging
8888  */
8889 void perf_log_lost_samples(struct perf_event *event, u64 lost)
8890 {
8891 	struct perf_output_handle handle;
8892 	struct perf_sample_data sample;
8893 	int ret;
8894 
8895 	struct {
8896 		struct perf_event_header	header;
8897 		u64				lost;
8898 	} lost_samples_event = {
8899 		.header = {
8900 			.type = PERF_RECORD_LOST_SAMPLES,
8901 			.misc = 0,
8902 			.size = sizeof(lost_samples_event),
8903 		},
8904 		.lost		= lost,
8905 	};
8906 
8907 	perf_event_header__init_id(&lost_samples_event.header, &sample, event);
8908 
8909 	ret = perf_output_begin(&handle, &sample, event,
8910 				lost_samples_event.header.size);
8911 	if (ret)
8912 		return;
8913 
8914 	perf_output_put(&handle, lost_samples_event);
8915 	perf_event__output_id_sample(event, &handle, &sample);
8916 	perf_output_end(&handle);
8917 }
8918 
8919 /*
8920  * context_switch tracking
8921  */
8922 
8923 struct perf_switch_event {
8924 	struct task_struct	*task;
8925 	struct task_struct	*next_prev;
8926 
8927 	struct {
8928 		struct perf_event_header	header;
8929 		u32				next_prev_pid;
8930 		u32				next_prev_tid;
8931 	} event_id;
8932 };
8933 
8934 static int perf_event_switch_match(struct perf_event *event)
8935 {
8936 	return event->attr.context_switch;
8937 }
8938 
8939 static void perf_event_switch_output(struct perf_event *event, void *data)
8940 {
8941 	struct perf_switch_event *se = data;
8942 	struct perf_output_handle handle;
8943 	struct perf_sample_data sample;
8944 	int ret;
8945 
8946 	if (!perf_event_switch_match(event))
8947 		return;
8948 
8949 	/* Only CPU-wide events are allowed to see next/prev pid/tid */
8950 	if (event->ctx->task) {
8951 		se->event_id.header.type = PERF_RECORD_SWITCH;
8952 		se->event_id.header.size = sizeof(se->event_id.header);
8953 	} else {
8954 		se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
8955 		se->event_id.header.size = sizeof(se->event_id);
8956 		se->event_id.next_prev_pid =
8957 					perf_event_pid(event, se->next_prev);
8958 		se->event_id.next_prev_tid =
8959 					perf_event_tid(event, se->next_prev);
8960 	}
8961 
8962 	perf_event_header__init_id(&se->event_id.header, &sample, event);
8963 
8964 	ret = perf_output_begin(&handle, &sample, event, se->event_id.header.size);
8965 	if (ret)
8966 		return;
8967 
8968 	if (event->ctx->task)
8969 		perf_output_put(&handle, se->event_id.header);
8970 	else
8971 		perf_output_put(&handle, se->event_id);
8972 
8973 	perf_event__output_id_sample(event, &handle, &sample);
8974 
8975 	perf_output_end(&handle);
8976 }
8977 
8978 static void perf_event_switch(struct task_struct *task,
8979 			      struct task_struct *next_prev, bool sched_in)
8980 {
8981 	struct perf_switch_event switch_event;
8982 
8983 	/* N.B. caller checks nr_switch_events != 0 */
8984 
8985 	switch_event = (struct perf_switch_event){
8986 		.task		= task,
8987 		.next_prev	= next_prev,
8988 		.event_id	= {
8989 			.header = {
8990 				/* .type */
8991 				.misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
8992 				/* .size */
8993 			},
8994 			/* .next_prev_pid */
8995 			/* .next_prev_tid */
8996 		},
8997 	};
8998 
8999 	if (!sched_in && task->on_rq) {
9000 		switch_event.event_id.header.misc |=
9001 				PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
9002 	}
9003 
9004 	perf_iterate_sb(perf_event_switch_output, &switch_event, NULL);
9005 }
9006 
9007 /*
9008  * IRQ throttle logging
9009  */
9010 
9011 static void perf_log_throttle(struct perf_event *event, int enable)
9012 {
9013 	struct perf_output_handle handle;
9014 	struct perf_sample_data sample;
9015 	int ret;
9016 
9017 	struct {
9018 		struct perf_event_header	header;
9019 		u64				time;
9020 		u64				id;
9021 		u64				stream_id;
9022 	} throttle_event = {
9023 		.header = {
9024 			.type = PERF_RECORD_THROTTLE,
9025 			.misc = 0,
9026 			.size = sizeof(throttle_event),
9027 		},
9028 		.time		= perf_event_clock(event),
9029 		.id		= primary_event_id(event),
9030 		.stream_id	= event->id,
9031 	};
9032 
9033 	if (enable)
9034 		throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
9035 
9036 	perf_event_header__init_id(&throttle_event.header, &sample, event);
9037 
9038 	ret = perf_output_begin(&handle, &sample, event,
9039 				throttle_event.header.size);
9040 	if (ret)
9041 		return;
9042 
9043 	perf_output_put(&handle, throttle_event);
9044 	perf_event__output_id_sample(event, &handle, &sample);
9045 	perf_output_end(&handle);
9046 }
9047 
9048 /*
9049  * ksymbol register/unregister tracking
9050  */
9051 
9052 struct perf_ksymbol_event {
9053 	const char	*name;
9054 	int		name_len;
9055 	struct {
9056 		struct perf_event_header        header;
9057 		u64				addr;
9058 		u32				len;
9059 		u16				ksym_type;
9060 		u16				flags;
9061 	} event_id;
9062 };
9063 
9064 static int perf_event_ksymbol_match(struct perf_event *event)
9065 {
9066 	return event->attr.ksymbol;
9067 }
9068 
9069 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
9070 {
9071 	struct perf_ksymbol_event *ksymbol_event = data;
9072 	struct perf_output_handle handle;
9073 	struct perf_sample_data sample;
9074 	int ret;
9075 
9076 	if (!perf_event_ksymbol_match(event))
9077 		return;
9078 
9079 	perf_event_header__init_id(&ksymbol_event->event_id.header,
9080 				   &sample, event);
9081 	ret = perf_output_begin(&handle, &sample, event,
9082 				ksymbol_event->event_id.header.size);
9083 	if (ret)
9084 		return;
9085 
9086 	perf_output_put(&handle, ksymbol_event->event_id);
9087 	__output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
9088 	perf_event__output_id_sample(event, &handle, &sample);
9089 
9090 	perf_output_end(&handle);
9091 }
9092 
9093 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
9094 			const char *sym)
9095 {
9096 	struct perf_ksymbol_event ksymbol_event;
9097 	char name[KSYM_NAME_LEN];
9098 	u16 flags = 0;
9099 	int name_len;
9100 
9101 	if (!atomic_read(&nr_ksymbol_events))
9102 		return;
9103 
9104 	if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
9105 	    ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
9106 		goto err;
9107 
9108 	strlcpy(name, sym, KSYM_NAME_LEN);
9109 	name_len = strlen(name) + 1;
9110 	while (!IS_ALIGNED(name_len, sizeof(u64)))
9111 		name[name_len++] = '\0';
9112 	BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
9113 
9114 	if (unregister)
9115 		flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
9116 
9117 	ksymbol_event = (struct perf_ksymbol_event){
9118 		.name = name,
9119 		.name_len = name_len,
9120 		.event_id = {
9121 			.header = {
9122 				.type = PERF_RECORD_KSYMBOL,
9123 				.size = sizeof(ksymbol_event.event_id) +
9124 					name_len,
9125 			},
9126 			.addr = addr,
9127 			.len = len,
9128 			.ksym_type = ksym_type,
9129 			.flags = flags,
9130 		},
9131 	};
9132 
9133 	perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
9134 	return;
9135 err:
9136 	WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
9137 }
9138 
9139 /*
9140  * bpf program load/unload tracking
9141  */
9142 
9143 struct perf_bpf_event {
9144 	struct bpf_prog	*prog;
9145 	struct {
9146 		struct perf_event_header        header;
9147 		u16				type;
9148 		u16				flags;
9149 		u32				id;
9150 		u8				tag[BPF_TAG_SIZE];
9151 	} event_id;
9152 };
9153 
9154 static int perf_event_bpf_match(struct perf_event *event)
9155 {
9156 	return event->attr.bpf_event;
9157 }
9158 
9159 static void perf_event_bpf_output(struct perf_event *event, void *data)
9160 {
9161 	struct perf_bpf_event *bpf_event = data;
9162 	struct perf_output_handle handle;
9163 	struct perf_sample_data sample;
9164 	int ret;
9165 
9166 	if (!perf_event_bpf_match(event))
9167 		return;
9168 
9169 	perf_event_header__init_id(&bpf_event->event_id.header,
9170 				   &sample, event);
9171 	ret = perf_output_begin(&handle, data, event,
9172 				bpf_event->event_id.header.size);
9173 	if (ret)
9174 		return;
9175 
9176 	perf_output_put(&handle, bpf_event->event_id);
9177 	perf_event__output_id_sample(event, &handle, &sample);
9178 
9179 	perf_output_end(&handle);
9180 }
9181 
9182 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
9183 					 enum perf_bpf_event_type type)
9184 {
9185 	bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
9186 	int i;
9187 
9188 	if (prog->aux->func_cnt == 0) {
9189 		perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
9190 				   (u64)(unsigned long)prog->bpf_func,
9191 				   prog->jited_len, unregister,
9192 				   prog->aux->ksym.name);
9193 	} else {
9194 		for (i = 0; i < prog->aux->func_cnt; i++) {
9195 			struct bpf_prog *subprog = prog->aux->func[i];
9196 
9197 			perf_event_ksymbol(
9198 				PERF_RECORD_KSYMBOL_TYPE_BPF,
9199 				(u64)(unsigned long)subprog->bpf_func,
9200 				subprog->jited_len, unregister,
9201 				subprog->aux->ksym.name);
9202 		}
9203 	}
9204 }
9205 
9206 void perf_event_bpf_event(struct bpf_prog *prog,
9207 			  enum perf_bpf_event_type type,
9208 			  u16 flags)
9209 {
9210 	struct perf_bpf_event bpf_event;
9211 
9212 	if (type <= PERF_BPF_EVENT_UNKNOWN ||
9213 	    type >= PERF_BPF_EVENT_MAX)
9214 		return;
9215 
9216 	switch (type) {
9217 	case PERF_BPF_EVENT_PROG_LOAD:
9218 	case PERF_BPF_EVENT_PROG_UNLOAD:
9219 		if (atomic_read(&nr_ksymbol_events))
9220 			perf_event_bpf_emit_ksymbols(prog, type);
9221 		break;
9222 	default:
9223 		break;
9224 	}
9225 
9226 	if (!atomic_read(&nr_bpf_events))
9227 		return;
9228 
9229 	bpf_event = (struct perf_bpf_event){
9230 		.prog = prog,
9231 		.event_id = {
9232 			.header = {
9233 				.type = PERF_RECORD_BPF_EVENT,
9234 				.size = sizeof(bpf_event.event_id),
9235 			},
9236 			.type = type,
9237 			.flags = flags,
9238 			.id = prog->aux->id,
9239 		},
9240 	};
9241 
9242 	BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
9243 
9244 	memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
9245 	perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
9246 }
9247 
9248 struct perf_text_poke_event {
9249 	const void		*old_bytes;
9250 	const void		*new_bytes;
9251 	size_t			pad;
9252 	u16			old_len;
9253 	u16			new_len;
9254 
9255 	struct {
9256 		struct perf_event_header	header;
9257 
9258 		u64				addr;
9259 	} event_id;
9260 };
9261 
9262 static int perf_event_text_poke_match(struct perf_event *event)
9263 {
9264 	return event->attr.text_poke;
9265 }
9266 
9267 static void perf_event_text_poke_output(struct perf_event *event, void *data)
9268 {
9269 	struct perf_text_poke_event *text_poke_event = data;
9270 	struct perf_output_handle handle;
9271 	struct perf_sample_data sample;
9272 	u64 padding = 0;
9273 	int ret;
9274 
9275 	if (!perf_event_text_poke_match(event))
9276 		return;
9277 
9278 	perf_event_header__init_id(&text_poke_event->event_id.header, &sample, event);
9279 
9280 	ret = perf_output_begin(&handle, &sample, event,
9281 				text_poke_event->event_id.header.size);
9282 	if (ret)
9283 		return;
9284 
9285 	perf_output_put(&handle, text_poke_event->event_id);
9286 	perf_output_put(&handle, text_poke_event->old_len);
9287 	perf_output_put(&handle, text_poke_event->new_len);
9288 
9289 	__output_copy(&handle, text_poke_event->old_bytes, text_poke_event->old_len);
9290 	__output_copy(&handle, text_poke_event->new_bytes, text_poke_event->new_len);
9291 
9292 	if (text_poke_event->pad)
9293 		__output_copy(&handle, &padding, text_poke_event->pad);
9294 
9295 	perf_event__output_id_sample(event, &handle, &sample);
9296 
9297 	perf_output_end(&handle);
9298 }
9299 
9300 void perf_event_text_poke(const void *addr, const void *old_bytes,
9301 			  size_t old_len, const void *new_bytes, size_t new_len)
9302 {
9303 	struct perf_text_poke_event text_poke_event;
9304 	size_t tot, pad;
9305 
9306 	if (!atomic_read(&nr_text_poke_events))
9307 		return;
9308 
9309 	tot  = sizeof(text_poke_event.old_len) + old_len;
9310 	tot += sizeof(text_poke_event.new_len) + new_len;
9311 	pad  = ALIGN(tot, sizeof(u64)) - tot;
9312 
9313 	text_poke_event = (struct perf_text_poke_event){
9314 		.old_bytes    = old_bytes,
9315 		.new_bytes    = new_bytes,
9316 		.pad          = pad,
9317 		.old_len      = old_len,
9318 		.new_len      = new_len,
9319 		.event_id  = {
9320 			.header = {
9321 				.type = PERF_RECORD_TEXT_POKE,
9322 				.misc = PERF_RECORD_MISC_KERNEL,
9323 				.size = sizeof(text_poke_event.event_id) + tot + pad,
9324 			},
9325 			.addr = (unsigned long)addr,
9326 		},
9327 	};
9328 
9329 	perf_iterate_sb(perf_event_text_poke_output, &text_poke_event, NULL);
9330 }
9331 
9332 void perf_event_itrace_started(struct perf_event *event)
9333 {
9334 	event->attach_state |= PERF_ATTACH_ITRACE;
9335 }
9336 
9337 static void perf_log_itrace_start(struct perf_event *event)
9338 {
9339 	struct perf_output_handle handle;
9340 	struct perf_sample_data sample;
9341 	struct perf_aux_event {
9342 		struct perf_event_header        header;
9343 		u32				pid;
9344 		u32				tid;
9345 	} rec;
9346 	int ret;
9347 
9348 	if (event->parent)
9349 		event = event->parent;
9350 
9351 	if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
9352 	    event->attach_state & PERF_ATTACH_ITRACE)
9353 		return;
9354 
9355 	rec.header.type	= PERF_RECORD_ITRACE_START;
9356 	rec.header.misc	= 0;
9357 	rec.header.size	= sizeof(rec);
9358 	rec.pid	= perf_event_pid(event, current);
9359 	rec.tid	= perf_event_tid(event, current);
9360 
9361 	perf_event_header__init_id(&rec.header, &sample, event);
9362 	ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9363 
9364 	if (ret)
9365 		return;
9366 
9367 	perf_output_put(&handle, rec);
9368 	perf_event__output_id_sample(event, &handle, &sample);
9369 
9370 	perf_output_end(&handle);
9371 }
9372 
9373 void perf_report_aux_output_id(struct perf_event *event, u64 hw_id)
9374 {
9375 	struct perf_output_handle handle;
9376 	struct perf_sample_data sample;
9377 	struct perf_aux_event {
9378 		struct perf_event_header        header;
9379 		u64				hw_id;
9380 	} rec;
9381 	int ret;
9382 
9383 	if (event->parent)
9384 		event = event->parent;
9385 
9386 	rec.header.type	= PERF_RECORD_AUX_OUTPUT_HW_ID;
9387 	rec.header.misc	= 0;
9388 	rec.header.size	= sizeof(rec);
9389 	rec.hw_id	= hw_id;
9390 
9391 	perf_event_header__init_id(&rec.header, &sample, event);
9392 	ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9393 
9394 	if (ret)
9395 		return;
9396 
9397 	perf_output_put(&handle, rec);
9398 	perf_event__output_id_sample(event, &handle, &sample);
9399 
9400 	perf_output_end(&handle);
9401 }
9402 
9403 static int
9404 __perf_event_account_interrupt(struct perf_event *event, int throttle)
9405 {
9406 	struct hw_perf_event *hwc = &event->hw;
9407 	int ret = 0;
9408 	u64 seq;
9409 
9410 	seq = __this_cpu_read(perf_throttled_seq);
9411 	if (seq != hwc->interrupts_seq) {
9412 		hwc->interrupts_seq = seq;
9413 		hwc->interrupts = 1;
9414 	} else {
9415 		hwc->interrupts++;
9416 		if (unlikely(throttle
9417 			     && hwc->interrupts >= max_samples_per_tick)) {
9418 			__this_cpu_inc(perf_throttled_count);
9419 			tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
9420 			hwc->interrupts = MAX_INTERRUPTS;
9421 			perf_log_throttle(event, 0);
9422 			ret = 1;
9423 		}
9424 	}
9425 
9426 	if (event->attr.freq) {
9427 		u64 now = perf_clock();
9428 		s64 delta = now - hwc->freq_time_stamp;
9429 
9430 		hwc->freq_time_stamp = now;
9431 
9432 		if (delta > 0 && delta < 2*TICK_NSEC)
9433 			perf_adjust_period(event, delta, hwc->last_period, true);
9434 	}
9435 
9436 	return ret;
9437 }
9438 
9439 int perf_event_account_interrupt(struct perf_event *event)
9440 {
9441 	return __perf_event_account_interrupt(event, 1);
9442 }
9443 
9444 static inline bool sample_is_allowed(struct perf_event *event, struct pt_regs *regs)
9445 {
9446 	/*
9447 	 * Due to interrupt latency (AKA "skid"), we may enter the
9448 	 * kernel before taking an overflow, even if the PMU is only
9449 	 * counting user events.
9450 	 */
9451 	if (event->attr.exclude_kernel && !user_mode(regs))
9452 		return false;
9453 
9454 	return true;
9455 }
9456 
9457 /*
9458  * Generic event overflow handling, sampling.
9459  */
9460 
9461 static int __perf_event_overflow(struct perf_event *event,
9462 				 int throttle, struct perf_sample_data *data,
9463 				 struct pt_regs *regs)
9464 {
9465 	int events = atomic_read(&event->event_limit);
9466 	int ret = 0;
9467 
9468 	/*
9469 	 * Non-sampling counters might still use the PMI to fold short
9470 	 * hardware counters, ignore those.
9471 	 */
9472 	if (unlikely(!is_sampling_event(event)))
9473 		return 0;
9474 
9475 	ret = __perf_event_account_interrupt(event, throttle);
9476 
9477 	/*
9478 	 * XXX event_limit might not quite work as expected on inherited
9479 	 * events
9480 	 */
9481 
9482 	event->pending_kill = POLL_IN;
9483 	if (events && atomic_dec_and_test(&event->event_limit)) {
9484 		ret = 1;
9485 		event->pending_kill = POLL_HUP;
9486 		perf_event_disable_inatomic(event);
9487 	}
9488 
9489 	if (event->attr.sigtrap) {
9490 		/*
9491 		 * The desired behaviour of sigtrap vs invalid samples is a bit
9492 		 * tricky; on the one hand, one should not loose the SIGTRAP if
9493 		 * it is the first event, on the other hand, we should also not
9494 		 * trigger the WARN or override the data address.
9495 		 */
9496 		bool valid_sample = sample_is_allowed(event, regs);
9497 		unsigned int pending_id = 1;
9498 
9499 		if (regs)
9500 			pending_id = hash32_ptr((void *)instruction_pointer(regs)) ?: 1;
9501 		if (!event->pending_sigtrap) {
9502 			event->pending_sigtrap = pending_id;
9503 			local_inc(&event->ctx->nr_pending);
9504 		} else if (event->attr.exclude_kernel && valid_sample) {
9505 			/*
9506 			 * Should not be able to return to user space without
9507 			 * consuming pending_sigtrap; with exceptions:
9508 			 *
9509 			 *  1. Where !exclude_kernel, events can overflow again
9510 			 *     in the kernel without returning to user space.
9511 			 *
9512 			 *  2. Events that can overflow again before the IRQ-
9513 			 *     work without user space progress (e.g. hrtimer).
9514 			 *     To approximate progress (with false negatives),
9515 			 *     check 32-bit hash of the current IP.
9516 			 */
9517 			WARN_ON_ONCE(event->pending_sigtrap != pending_id);
9518 		}
9519 
9520 		event->pending_addr = 0;
9521 		if (valid_sample && (data->sample_flags & PERF_SAMPLE_ADDR))
9522 			event->pending_addr = data->addr;
9523 		irq_work_queue(&event->pending_irq);
9524 	}
9525 
9526 	READ_ONCE(event->overflow_handler)(event, data, regs);
9527 
9528 	if (*perf_event_fasync(event) && event->pending_kill) {
9529 		event->pending_wakeup = 1;
9530 		irq_work_queue(&event->pending_irq);
9531 	}
9532 
9533 	return ret;
9534 }
9535 
9536 int perf_event_overflow(struct perf_event *event,
9537 			struct perf_sample_data *data,
9538 			struct pt_regs *regs)
9539 {
9540 	return __perf_event_overflow(event, 1, data, regs);
9541 }
9542 
9543 /*
9544  * Generic software event infrastructure
9545  */
9546 
9547 struct swevent_htable {
9548 	struct swevent_hlist		*swevent_hlist;
9549 	struct mutex			hlist_mutex;
9550 	int				hlist_refcount;
9551 
9552 	/* Recursion avoidance in each contexts */
9553 	int				recursion[PERF_NR_CONTEXTS];
9554 };
9555 
9556 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
9557 
9558 /*
9559  * We directly increment event->count and keep a second value in
9560  * event->hw.period_left to count intervals. This period event
9561  * is kept in the range [-sample_period, 0] so that we can use the
9562  * sign as trigger.
9563  */
9564 
9565 u64 perf_swevent_set_period(struct perf_event *event)
9566 {
9567 	struct hw_perf_event *hwc = &event->hw;
9568 	u64 period = hwc->last_period;
9569 	u64 nr, offset;
9570 	s64 old, val;
9571 
9572 	hwc->last_period = hwc->sample_period;
9573 
9574 again:
9575 	old = val = local64_read(&hwc->period_left);
9576 	if (val < 0)
9577 		return 0;
9578 
9579 	nr = div64_u64(period + val, period);
9580 	offset = nr * period;
9581 	val -= offset;
9582 	if (local64_cmpxchg(&hwc->period_left, old, val) != old)
9583 		goto again;
9584 
9585 	return nr;
9586 }
9587 
9588 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
9589 				    struct perf_sample_data *data,
9590 				    struct pt_regs *regs)
9591 {
9592 	struct hw_perf_event *hwc = &event->hw;
9593 	int throttle = 0;
9594 
9595 	if (!overflow)
9596 		overflow = perf_swevent_set_period(event);
9597 
9598 	if (hwc->interrupts == MAX_INTERRUPTS)
9599 		return;
9600 
9601 	for (; overflow; overflow--) {
9602 		if (__perf_event_overflow(event, throttle,
9603 					    data, regs)) {
9604 			/*
9605 			 * We inhibit the overflow from happening when
9606 			 * hwc->interrupts == MAX_INTERRUPTS.
9607 			 */
9608 			break;
9609 		}
9610 		throttle = 1;
9611 	}
9612 }
9613 
9614 static void perf_swevent_event(struct perf_event *event, u64 nr,
9615 			       struct perf_sample_data *data,
9616 			       struct pt_regs *regs)
9617 {
9618 	struct hw_perf_event *hwc = &event->hw;
9619 
9620 	local64_add(nr, &event->count);
9621 
9622 	if (!regs)
9623 		return;
9624 
9625 	if (!is_sampling_event(event))
9626 		return;
9627 
9628 	if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
9629 		data->period = nr;
9630 		return perf_swevent_overflow(event, 1, data, regs);
9631 	} else
9632 		data->period = event->hw.last_period;
9633 
9634 	if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
9635 		return perf_swevent_overflow(event, 1, data, regs);
9636 
9637 	if (local64_add_negative(nr, &hwc->period_left))
9638 		return;
9639 
9640 	perf_swevent_overflow(event, 0, data, regs);
9641 }
9642 
9643 static int perf_exclude_event(struct perf_event *event,
9644 			      struct pt_regs *regs)
9645 {
9646 	if (event->hw.state & PERF_HES_STOPPED)
9647 		return 1;
9648 
9649 	if (regs) {
9650 		if (event->attr.exclude_user && user_mode(regs))
9651 			return 1;
9652 
9653 		if (event->attr.exclude_kernel && !user_mode(regs))
9654 			return 1;
9655 	}
9656 
9657 	return 0;
9658 }
9659 
9660 static int perf_swevent_match(struct perf_event *event,
9661 				enum perf_type_id type,
9662 				u32 event_id,
9663 				struct perf_sample_data *data,
9664 				struct pt_regs *regs)
9665 {
9666 	if (event->attr.type != type)
9667 		return 0;
9668 
9669 	if (event->attr.config != event_id)
9670 		return 0;
9671 
9672 	if (perf_exclude_event(event, regs))
9673 		return 0;
9674 
9675 	return 1;
9676 }
9677 
9678 static inline u64 swevent_hash(u64 type, u32 event_id)
9679 {
9680 	u64 val = event_id | (type << 32);
9681 
9682 	return hash_64(val, SWEVENT_HLIST_BITS);
9683 }
9684 
9685 static inline struct hlist_head *
9686 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
9687 {
9688 	u64 hash = swevent_hash(type, event_id);
9689 
9690 	return &hlist->heads[hash];
9691 }
9692 
9693 /* For the read side: events when they trigger */
9694 static inline struct hlist_head *
9695 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
9696 {
9697 	struct swevent_hlist *hlist;
9698 
9699 	hlist = rcu_dereference(swhash->swevent_hlist);
9700 	if (!hlist)
9701 		return NULL;
9702 
9703 	return __find_swevent_head(hlist, type, event_id);
9704 }
9705 
9706 /* For the event head insertion and removal in the hlist */
9707 static inline struct hlist_head *
9708 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
9709 {
9710 	struct swevent_hlist *hlist;
9711 	u32 event_id = event->attr.config;
9712 	u64 type = event->attr.type;
9713 
9714 	/*
9715 	 * Event scheduling is always serialized against hlist allocation
9716 	 * and release. Which makes the protected version suitable here.
9717 	 * The context lock guarantees that.
9718 	 */
9719 	hlist = rcu_dereference_protected(swhash->swevent_hlist,
9720 					  lockdep_is_held(&event->ctx->lock));
9721 	if (!hlist)
9722 		return NULL;
9723 
9724 	return __find_swevent_head(hlist, type, event_id);
9725 }
9726 
9727 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
9728 				    u64 nr,
9729 				    struct perf_sample_data *data,
9730 				    struct pt_regs *regs)
9731 {
9732 	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9733 	struct perf_event *event;
9734 	struct hlist_head *head;
9735 
9736 	rcu_read_lock();
9737 	head = find_swevent_head_rcu(swhash, type, event_id);
9738 	if (!head)
9739 		goto end;
9740 
9741 	hlist_for_each_entry_rcu(event, head, hlist_entry) {
9742 		if (perf_swevent_match(event, type, event_id, data, regs))
9743 			perf_swevent_event(event, nr, data, regs);
9744 	}
9745 end:
9746 	rcu_read_unlock();
9747 }
9748 
9749 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
9750 
9751 int perf_swevent_get_recursion_context(void)
9752 {
9753 	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9754 
9755 	return get_recursion_context(swhash->recursion);
9756 }
9757 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
9758 
9759 void perf_swevent_put_recursion_context(int rctx)
9760 {
9761 	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9762 
9763 	put_recursion_context(swhash->recursion, rctx);
9764 }
9765 
9766 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9767 {
9768 	struct perf_sample_data data;
9769 
9770 	if (WARN_ON_ONCE(!regs))
9771 		return;
9772 
9773 	perf_sample_data_init(&data, addr, 0);
9774 	do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
9775 }
9776 
9777 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9778 {
9779 	int rctx;
9780 
9781 	preempt_disable_notrace();
9782 	rctx = perf_swevent_get_recursion_context();
9783 	if (unlikely(rctx < 0))
9784 		goto fail;
9785 
9786 	___perf_sw_event(event_id, nr, regs, addr);
9787 
9788 	perf_swevent_put_recursion_context(rctx);
9789 fail:
9790 	preempt_enable_notrace();
9791 }
9792 
9793 static void perf_swevent_read(struct perf_event *event)
9794 {
9795 }
9796 
9797 static int perf_swevent_add(struct perf_event *event, int flags)
9798 {
9799 	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9800 	struct hw_perf_event *hwc = &event->hw;
9801 	struct hlist_head *head;
9802 
9803 	if (is_sampling_event(event)) {
9804 		hwc->last_period = hwc->sample_period;
9805 		perf_swevent_set_period(event);
9806 	}
9807 
9808 	hwc->state = !(flags & PERF_EF_START);
9809 
9810 	head = find_swevent_head(swhash, event);
9811 	if (WARN_ON_ONCE(!head))
9812 		return -EINVAL;
9813 
9814 	hlist_add_head_rcu(&event->hlist_entry, head);
9815 	perf_event_update_userpage(event);
9816 
9817 	return 0;
9818 }
9819 
9820 static void perf_swevent_del(struct perf_event *event, int flags)
9821 {
9822 	hlist_del_rcu(&event->hlist_entry);
9823 }
9824 
9825 static void perf_swevent_start(struct perf_event *event, int flags)
9826 {
9827 	event->hw.state = 0;
9828 }
9829 
9830 static void perf_swevent_stop(struct perf_event *event, int flags)
9831 {
9832 	event->hw.state = PERF_HES_STOPPED;
9833 }
9834 
9835 /* Deref the hlist from the update side */
9836 static inline struct swevent_hlist *
9837 swevent_hlist_deref(struct swevent_htable *swhash)
9838 {
9839 	return rcu_dereference_protected(swhash->swevent_hlist,
9840 					 lockdep_is_held(&swhash->hlist_mutex));
9841 }
9842 
9843 static void swevent_hlist_release(struct swevent_htable *swhash)
9844 {
9845 	struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
9846 
9847 	if (!hlist)
9848 		return;
9849 
9850 	RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
9851 	kfree_rcu(hlist, rcu_head);
9852 }
9853 
9854 static void swevent_hlist_put_cpu(int cpu)
9855 {
9856 	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9857 
9858 	mutex_lock(&swhash->hlist_mutex);
9859 
9860 	if (!--swhash->hlist_refcount)
9861 		swevent_hlist_release(swhash);
9862 
9863 	mutex_unlock(&swhash->hlist_mutex);
9864 }
9865 
9866 static void swevent_hlist_put(void)
9867 {
9868 	int cpu;
9869 
9870 	for_each_possible_cpu(cpu)
9871 		swevent_hlist_put_cpu(cpu);
9872 }
9873 
9874 static int swevent_hlist_get_cpu(int cpu)
9875 {
9876 	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9877 	int err = 0;
9878 
9879 	mutex_lock(&swhash->hlist_mutex);
9880 	if (!swevent_hlist_deref(swhash) &&
9881 	    cpumask_test_cpu(cpu, perf_online_mask)) {
9882 		struct swevent_hlist *hlist;
9883 
9884 		hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
9885 		if (!hlist) {
9886 			err = -ENOMEM;
9887 			goto exit;
9888 		}
9889 		rcu_assign_pointer(swhash->swevent_hlist, hlist);
9890 	}
9891 	swhash->hlist_refcount++;
9892 exit:
9893 	mutex_unlock(&swhash->hlist_mutex);
9894 
9895 	return err;
9896 }
9897 
9898 static int swevent_hlist_get(void)
9899 {
9900 	int err, cpu, failed_cpu;
9901 
9902 	mutex_lock(&pmus_lock);
9903 	for_each_possible_cpu(cpu) {
9904 		err = swevent_hlist_get_cpu(cpu);
9905 		if (err) {
9906 			failed_cpu = cpu;
9907 			goto fail;
9908 		}
9909 	}
9910 	mutex_unlock(&pmus_lock);
9911 	return 0;
9912 fail:
9913 	for_each_possible_cpu(cpu) {
9914 		if (cpu == failed_cpu)
9915 			break;
9916 		swevent_hlist_put_cpu(cpu);
9917 	}
9918 	mutex_unlock(&pmus_lock);
9919 	return err;
9920 }
9921 
9922 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
9923 
9924 static void sw_perf_event_destroy(struct perf_event *event)
9925 {
9926 	u64 event_id = event->attr.config;
9927 
9928 	WARN_ON(event->parent);
9929 
9930 	static_key_slow_dec(&perf_swevent_enabled[event_id]);
9931 	swevent_hlist_put();
9932 }
9933 
9934 static int perf_swevent_init(struct perf_event *event)
9935 {
9936 	u64 event_id = event->attr.config;
9937 
9938 	if (event->attr.type != PERF_TYPE_SOFTWARE)
9939 		return -ENOENT;
9940 
9941 	/*
9942 	 * no branch sampling for software events
9943 	 */
9944 	if (has_branch_stack(event))
9945 		return -EOPNOTSUPP;
9946 
9947 	switch (event_id) {
9948 	case PERF_COUNT_SW_CPU_CLOCK:
9949 	case PERF_COUNT_SW_TASK_CLOCK:
9950 		return -ENOENT;
9951 
9952 	default:
9953 		break;
9954 	}
9955 
9956 	if (event_id >= PERF_COUNT_SW_MAX)
9957 		return -ENOENT;
9958 
9959 	if (!event->parent) {
9960 		int err;
9961 
9962 		err = swevent_hlist_get();
9963 		if (err)
9964 			return err;
9965 
9966 		static_key_slow_inc(&perf_swevent_enabled[event_id]);
9967 		event->destroy = sw_perf_event_destroy;
9968 	}
9969 
9970 	return 0;
9971 }
9972 
9973 static struct pmu perf_swevent = {
9974 	.task_ctx_nr	= perf_sw_context,
9975 
9976 	.capabilities	= PERF_PMU_CAP_NO_NMI,
9977 
9978 	.event_init	= perf_swevent_init,
9979 	.add		= perf_swevent_add,
9980 	.del		= perf_swevent_del,
9981 	.start		= perf_swevent_start,
9982 	.stop		= perf_swevent_stop,
9983 	.read		= perf_swevent_read,
9984 };
9985 
9986 #ifdef CONFIG_EVENT_TRACING
9987 
9988 static void tp_perf_event_destroy(struct perf_event *event)
9989 {
9990 	perf_trace_destroy(event);
9991 }
9992 
9993 static int perf_tp_event_init(struct perf_event *event)
9994 {
9995 	int err;
9996 
9997 	if (event->attr.type != PERF_TYPE_TRACEPOINT)
9998 		return -ENOENT;
9999 
10000 	/*
10001 	 * no branch sampling for tracepoint events
10002 	 */
10003 	if (has_branch_stack(event))
10004 		return -EOPNOTSUPP;
10005 
10006 	err = perf_trace_init(event);
10007 	if (err)
10008 		return err;
10009 
10010 	event->destroy = tp_perf_event_destroy;
10011 
10012 	return 0;
10013 }
10014 
10015 static struct pmu perf_tracepoint = {
10016 	.task_ctx_nr	= perf_sw_context,
10017 
10018 	.event_init	= perf_tp_event_init,
10019 	.add		= perf_trace_add,
10020 	.del		= perf_trace_del,
10021 	.start		= perf_swevent_start,
10022 	.stop		= perf_swevent_stop,
10023 	.read		= perf_swevent_read,
10024 };
10025 
10026 static int perf_tp_filter_match(struct perf_event *event,
10027 				struct perf_sample_data *data)
10028 {
10029 	void *record = data->raw->frag.data;
10030 
10031 	/* only top level events have filters set */
10032 	if (event->parent)
10033 		event = event->parent;
10034 
10035 	if (likely(!event->filter) || filter_match_preds(event->filter, record))
10036 		return 1;
10037 	return 0;
10038 }
10039 
10040 static int perf_tp_event_match(struct perf_event *event,
10041 				struct perf_sample_data *data,
10042 				struct pt_regs *regs)
10043 {
10044 	if (event->hw.state & PERF_HES_STOPPED)
10045 		return 0;
10046 	/*
10047 	 * If exclude_kernel, only trace user-space tracepoints (uprobes)
10048 	 */
10049 	if (event->attr.exclude_kernel && !user_mode(regs))
10050 		return 0;
10051 
10052 	if (!perf_tp_filter_match(event, data))
10053 		return 0;
10054 
10055 	return 1;
10056 }
10057 
10058 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
10059 			       struct trace_event_call *call, u64 count,
10060 			       struct pt_regs *regs, struct hlist_head *head,
10061 			       struct task_struct *task)
10062 {
10063 	if (bpf_prog_array_valid(call)) {
10064 		*(struct pt_regs **)raw_data = regs;
10065 		if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
10066 			perf_swevent_put_recursion_context(rctx);
10067 			return;
10068 		}
10069 	}
10070 	perf_tp_event(call->event.type, count, raw_data, size, regs, head,
10071 		      rctx, task);
10072 }
10073 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
10074 
10075 static void __perf_tp_event_target_task(u64 count, void *record,
10076 					struct pt_regs *regs,
10077 					struct perf_sample_data *data,
10078 					struct perf_event *event)
10079 {
10080 	struct trace_entry *entry = record;
10081 
10082 	if (event->attr.config != entry->type)
10083 		return;
10084 	/* Cannot deliver synchronous signal to other task. */
10085 	if (event->attr.sigtrap)
10086 		return;
10087 	if (perf_tp_event_match(event, data, regs))
10088 		perf_swevent_event(event, count, data, regs);
10089 }
10090 
10091 static void perf_tp_event_target_task(u64 count, void *record,
10092 				      struct pt_regs *regs,
10093 				      struct perf_sample_data *data,
10094 				      struct perf_event_context *ctx)
10095 {
10096 	unsigned int cpu = smp_processor_id();
10097 	struct pmu *pmu = &perf_tracepoint;
10098 	struct perf_event *event, *sibling;
10099 
10100 	perf_event_groups_for_cpu_pmu(event, &ctx->pinned_groups, cpu, pmu) {
10101 		__perf_tp_event_target_task(count, record, regs, data, event);
10102 		for_each_sibling_event(sibling, event)
10103 			__perf_tp_event_target_task(count, record, regs, data, sibling);
10104 	}
10105 
10106 	perf_event_groups_for_cpu_pmu(event, &ctx->flexible_groups, cpu, pmu) {
10107 		__perf_tp_event_target_task(count, record, regs, data, event);
10108 		for_each_sibling_event(sibling, event)
10109 			__perf_tp_event_target_task(count, record, regs, data, sibling);
10110 	}
10111 }
10112 
10113 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
10114 		   struct pt_regs *regs, struct hlist_head *head, int rctx,
10115 		   struct task_struct *task)
10116 {
10117 	struct perf_sample_data data;
10118 	struct perf_event *event;
10119 
10120 	struct perf_raw_record raw = {
10121 		.frag = {
10122 			.size = entry_size,
10123 			.data = record,
10124 		},
10125 	};
10126 
10127 	perf_sample_data_init(&data, 0, 0);
10128 	data.raw = &raw;
10129 	data.sample_flags |= PERF_SAMPLE_RAW;
10130 
10131 	perf_trace_buf_update(record, event_type);
10132 
10133 	hlist_for_each_entry_rcu(event, head, hlist_entry) {
10134 		if (perf_tp_event_match(event, &data, regs))
10135 			perf_swevent_event(event, count, &data, regs);
10136 	}
10137 
10138 	/*
10139 	 * If we got specified a target task, also iterate its context and
10140 	 * deliver this event there too.
10141 	 */
10142 	if (task && task != current) {
10143 		struct perf_event_context *ctx;
10144 
10145 		rcu_read_lock();
10146 		ctx = rcu_dereference(task->perf_event_ctxp);
10147 		if (!ctx)
10148 			goto unlock;
10149 
10150 		raw_spin_lock(&ctx->lock);
10151 		perf_tp_event_target_task(count, record, regs, &data, ctx);
10152 		raw_spin_unlock(&ctx->lock);
10153 unlock:
10154 		rcu_read_unlock();
10155 	}
10156 
10157 	perf_swevent_put_recursion_context(rctx);
10158 }
10159 EXPORT_SYMBOL_GPL(perf_tp_event);
10160 
10161 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
10162 /*
10163  * Flags in config, used by dynamic PMU kprobe and uprobe
10164  * The flags should match following PMU_FORMAT_ATTR().
10165  *
10166  * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
10167  *                               if not set, create kprobe/uprobe
10168  *
10169  * The following values specify a reference counter (or semaphore in the
10170  * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
10171  * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
10172  *
10173  * PERF_UPROBE_REF_CTR_OFFSET_BITS	# of bits in config as th offset
10174  * PERF_UPROBE_REF_CTR_OFFSET_SHIFT	# of bits to shift left
10175  */
10176 enum perf_probe_config {
10177 	PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0,  /* [k,u]retprobe */
10178 	PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
10179 	PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
10180 };
10181 
10182 PMU_FORMAT_ATTR(retprobe, "config:0");
10183 #endif
10184 
10185 #ifdef CONFIG_KPROBE_EVENTS
10186 static struct attribute *kprobe_attrs[] = {
10187 	&format_attr_retprobe.attr,
10188 	NULL,
10189 };
10190 
10191 static struct attribute_group kprobe_format_group = {
10192 	.name = "format",
10193 	.attrs = kprobe_attrs,
10194 };
10195 
10196 static const struct attribute_group *kprobe_attr_groups[] = {
10197 	&kprobe_format_group,
10198 	NULL,
10199 };
10200 
10201 static int perf_kprobe_event_init(struct perf_event *event);
10202 static struct pmu perf_kprobe = {
10203 	.task_ctx_nr	= perf_sw_context,
10204 	.event_init	= perf_kprobe_event_init,
10205 	.add		= perf_trace_add,
10206 	.del		= perf_trace_del,
10207 	.start		= perf_swevent_start,
10208 	.stop		= perf_swevent_stop,
10209 	.read		= perf_swevent_read,
10210 	.attr_groups	= kprobe_attr_groups,
10211 };
10212 
10213 static int perf_kprobe_event_init(struct perf_event *event)
10214 {
10215 	int err;
10216 	bool is_retprobe;
10217 
10218 	if (event->attr.type != perf_kprobe.type)
10219 		return -ENOENT;
10220 
10221 	if (!perfmon_capable())
10222 		return -EACCES;
10223 
10224 	/*
10225 	 * no branch sampling for probe events
10226 	 */
10227 	if (has_branch_stack(event))
10228 		return -EOPNOTSUPP;
10229 
10230 	is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
10231 	err = perf_kprobe_init(event, is_retprobe);
10232 	if (err)
10233 		return err;
10234 
10235 	event->destroy = perf_kprobe_destroy;
10236 
10237 	return 0;
10238 }
10239 #endif /* CONFIG_KPROBE_EVENTS */
10240 
10241 #ifdef CONFIG_UPROBE_EVENTS
10242 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
10243 
10244 static struct attribute *uprobe_attrs[] = {
10245 	&format_attr_retprobe.attr,
10246 	&format_attr_ref_ctr_offset.attr,
10247 	NULL,
10248 };
10249 
10250 static struct attribute_group uprobe_format_group = {
10251 	.name = "format",
10252 	.attrs = uprobe_attrs,
10253 };
10254 
10255 static const struct attribute_group *uprobe_attr_groups[] = {
10256 	&uprobe_format_group,
10257 	NULL,
10258 };
10259 
10260 static int perf_uprobe_event_init(struct perf_event *event);
10261 static struct pmu perf_uprobe = {
10262 	.task_ctx_nr	= perf_sw_context,
10263 	.event_init	= perf_uprobe_event_init,
10264 	.add		= perf_trace_add,
10265 	.del		= perf_trace_del,
10266 	.start		= perf_swevent_start,
10267 	.stop		= perf_swevent_stop,
10268 	.read		= perf_swevent_read,
10269 	.attr_groups	= uprobe_attr_groups,
10270 };
10271 
10272 static int perf_uprobe_event_init(struct perf_event *event)
10273 {
10274 	int err;
10275 	unsigned long ref_ctr_offset;
10276 	bool is_retprobe;
10277 
10278 	if (event->attr.type != perf_uprobe.type)
10279 		return -ENOENT;
10280 
10281 	if (!perfmon_capable())
10282 		return -EACCES;
10283 
10284 	/*
10285 	 * no branch sampling for probe events
10286 	 */
10287 	if (has_branch_stack(event))
10288 		return -EOPNOTSUPP;
10289 
10290 	is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
10291 	ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
10292 	err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
10293 	if (err)
10294 		return err;
10295 
10296 	event->destroy = perf_uprobe_destroy;
10297 
10298 	return 0;
10299 }
10300 #endif /* CONFIG_UPROBE_EVENTS */
10301 
10302 static inline void perf_tp_register(void)
10303 {
10304 	perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
10305 #ifdef CONFIG_KPROBE_EVENTS
10306 	perf_pmu_register(&perf_kprobe, "kprobe", -1);
10307 #endif
10308 #ifdef CONFIG_UPROBE_EVENTS
10309 	perf_pmu_register(&perf_uprobe, "uprobe", -1);
10310 #endif
10311 }
10312 
10313 static void perf_event_free_filter(struct perf_event *event)
10314 {
10315 	ftrace_profile_free_filter(event);
10316 }
10317 
10318 #ifdef CONFIG_BPF_SYSCALL
10319 static void bpf_overflow_handler(struct perf_event *event,
10320 				 struct perf_sample_data *data,
10321 				 struct pt_regs *regs)
10322 {
10323 	struct bpf_perf_event_data_kern ctx = {
10324 		.data = data,
10325 		.event = event,
10326 	};
10327 	struct bpf_prog *prog;
10328 	int ret = 0;
10329 
10330 	ctx.regs = perf_arch_bpf_user_pt_regs(regs);
10331 	if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
10332 		goto out;
10333 	rcu_read_lock();
10334 	prog = READ_ONCE(event->prog);
10335 	if (prog) {
10336 		if (prog->call_get_stack &&
10337 		    (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) &&
10338 		    !(data->sample_flags & PERF_SAMPLE_CALLCHAIN)) {
10339 			data->callchain = perf_callchain(event, regs);
10340 			data->sample_flags |= PERF_SAMPLE_CALLCHAIN;
10341 		}
10342 
10343 		ret = bpf_prog_run(prog, &ctx);
10344 	}
10345 	rcu_read_unlock();
10346 out:
10347 	__this_cpu_dec(bpf_prog_active);
10348 	if (!ret)
10349 		return;
10350 
10351 	event->orig_overflow_handler(event, data, regs);
10352 }
10353 
10354 static int perf_event_set_bpf_handler(struct perf_event *event,
10355 				      struct bpf_prog *prog,
10356 				      u64 bpf_cookie)
10357 {
10358 	if (event->overflow_handler_context)
10359 		/* hw breakpoint or kernel counter */
10360 		return -EINVAL;
10361 
10362 	if (event->prog)
10363 		return -EEXIST;
10364 
10365 	if (prog->type != BPF_PROG_TYPE_PERF_EVENT)
10366 		return -EINVAL;
10367 
10368 	if (event->attr.precise_ip &&
10369 	    prog->call_get_stack &&
10370 	    (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) ||
10371 	     event->attr.exclude_callchain_kernel ||
10372 	     event->attr.exclude_callchain_user)) {
10373 		/*
10374 		 * On perf_event with precise_ip, calling bpf_get_stack()
10375 		 * may trigger unwinder warnings and occasional crashes.
10376 		 * bpf_get_[stack|stackid] works around this issue by using
10377 		 * callchain attached to perf_sample_data. If the
10378 		 * perf_event does not full (kernel and user) callchain
10379 		 * attached to perf_sample_data, do not allow attaching BPF
10380 		 * program that calls bpf_get_[stack|stackid].
10381 		 */
10382 		return -EPROTO;
10383 	}
10384 
10385 	event->prog = prog;
10386 	event->bpf_cookie = bpf_cookie;
10387 	event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
10388 	WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
10389 	return 0;
10390 }
10391 
10392 static void perf_event_free_bpf_handler(struct perf_event *event)
10393 {
10394 	struct bpf_prog *prog = event->prog;
10395 
10396 	if (!prog)
10397 		return;
10398 
10399 	WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
10400 	event->prog = NULL;
10401 	bpf_prog_put(prog);
10402 }
10403 #else
10404 static int perf_event_set_bpf_handler(struct perf_event *event,
10405 				      struct bpf_prog *prog,
10406 				      u64 bpf_cookie)
10407 {
10408 	return -EOPNOTSUPP;
10409 }
10410 static void perf_event_free_bpf_handler(struct perf_event *event)
10411 {
10412 }
10413 #endif
10414 
10415 /*
10416  * returns true if the event is a tracepoint, or a kprobe/upprobe created
10417  * with perf_event_open()
10418  */
10419 static inline bool perf_event_is_tracing(struct perf_event *event)
10420 {
10421 	if (event->pmu == &perf_tracepoint)
10422 		return true;
10423 #ifdef CONFIG_KPROBE_EVENTS
10424 	if (event->pmu == &perf_kprobe)
10425 		return true;
10426 #endif
10427 #ifdef CONFIG_UPROBE_EVENTS
10428 	if (event->pmu == &perf_uprobe)
10429 		return true;
10430 #endif
10431 	return false;
10432 }
10433 
10434 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
10435 			    u64 bpf_cookie)
10436 {
10437 	bool is_kprobe, is_uprobe, is_tracepoint, is_syscall_tp;
10438 
10439 	if (!perf_event_is_tracing(event))
10440 		return perf_event_set_bpf_handler(event, prog, bpf_cookie);
10441 
10442 	is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_KPROBE;
10443 	is_uprobe = event->tp_event->flags & TRACE_EVENT_FL_UPROBE;
10444 	is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
10445 	is_syscall_tp = is_syscall_trace_event(event->tp_event);
10446 	if (!is_kprobe && !is_uprobe && !is_tracepoint && !is_syscall_tp)
10447 		/* bpf programs can only be attached to u/kprobe or tracepoint */
10448 		return -EINVAL;
10449 
10450 	if (((is_kprobe || is_uprobe) && prog->type != BPF_PROG_TYPE_KPROBE) ||
10451 	    (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
10452 	    (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT))
10453 		return -EINVAL;
10454 
10455 	if (prog->type == BPF_PROG_TYPE_KPROBE && prog->aux->sleepable && !is_uprobe)
10456 		/* only uprobe programs are allowed to be sleepable */
10457 		return -EINVAL;
10458 
10459 	/* Kprobe override only works for kprobes, not uprobes. */
10460 	if (prog->kprobe_override && !is_kprobe)
10461 		return -EINVAL;
10462 
10463 	if (is_tracepoint || is_syscall_tp) {
10464 		int off = trace_event_get_offsets(event->tp_event);
10465 
10466 		if (prog->aux->max_ctx_offset > off)
10467 			return -EACCES;
10468 	}
10469 
10470 	return perf_event_attach_bpf_prog(event, prog, bpf_cookie);
10471 }
10472 
10473 void perf_event_free_bpf_prog(struct perf_event *event)
10474 {
10475 	if (!perf_event_is_tracing(event)) {
10476 		perf_event_free_bpf_handler(event);
10477 		return;
10478 	}
10479 	perf_event_detach_bpf_prog(event);
10480 }
10481 
10482 #else
10483 
10484 static inline void perf_tp_register(void)
10485 {
10486 }
10487 
10488 static void perf_event_free_filter(struct perf_event *event)
10489 {
10490 }
10491 
10492 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
10493 			    u64 bpf_cookie)
10494 {
10495 	return -ENOENT;
10496 }
10497 
10498 void perf_event_free_bpf_prog(struct perf_event *event)
10499 {
10500 }
10501 #endif /* CONFIG_EVENT_TRACING */
10502 
10503 #ifdef CONFIG_HAVE_HW_BREAKPOINT
10504 void perf_bp_event(struct perf_event *bp, void *data)
10505 {
10506 	struct perf_sample_data sample;
10507 	struct pt_regs *regs = data;
10508 
10509 	perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
10510 
10511 	if (!bp->hw.state && !perf_exclude_event(bp, regs))
10512 		perf_swevent_event(bp, 1, &sample, regs);
10513 }
10514 #endif
10515 
10516 /*
10517  * Allocate a new address filter
10518  */
10519 static struct perf_addr_filter *
10520 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
10521 {
10522 	int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
10523 	struct perf_addr_filter *filter;
10524 
10525 	filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
10526 	if (!filter)
10527 		return NULL;
10528 
10529 	INIT_LIST_HEAD(&filter->entry);
10530 	list_add_tail(&filter->entry, filters);
10531 
10532 	return filter;
10533 }
10534 
10535 static void free_filters_list(struct list_head *filters)
10536 {
10537 	struct perf_addr_filter *filter, *iter;
10538 
10539 	list_for_each_entry_safe(filter, iter, filters, entry) {
10540 		path_put(&filter->path);
10541 		list_del(&filter->entry);
10542 		kfree(filter);
10543 	}
10544 }
10545 
10546 /*
10547  * Free existing address filters and optionally install new ones
10548  */
10549 static void perf_addr_filters_splice(struct perf_event *event,
10550 				     struct list_head *head)
10551 {
10552 	unsigned long flags;
10553 	LIST_HEAD(list);
10554 
10555 	if (!has_addr_filter(event))
10556 		return;
10557 
10558 	/* don't bother with children, they don't have their own filters */
10559 	if (event->parent)
10560 		return;
10561 
10562 	raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
10563 
10564 	list_splice_init(&event->addr_filters.list, &list);
10565 	if (head)
10566 		list_splice(head, &event->addr_filters.list);
10567 
10568 	raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
10569 
10570 	free_filters_list(&list);
10571 }
10572 
10573 /*
10574  * Scan through mm's vmas and see if one of them matches the
10575  * @filter; if so, adjust filter's address range.
10576  * Called with mm::mmap_lock down for reading.
10577  */
10578 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
10579 				   struct mm_struct *mm,
10580 				   struct perf_addr_filter_range *fr)
10581 {
10582 	struct vm_area_struct *vma;
10583 	VMA_ITERATOR(vmi, mm, 0);
10584 
10585 	for_each_vma(vmi, vma) {
10586 		if (!vma->vm_file)
10587 			continue;
10588 
10589 		if (perf_addr_filter_vma_adjust(filter, vma, fr))
10590 			return;
10591 	}
10592 }
10593 
10594 /*
10595  * Update event's address range filters based on the
10596  * task's existing mappings, if any.
10597  */
10598 static void perf_event_addr_filters_apply(struct perf_event *event)
10599 {
10600 	struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10601 	struct task_struct *task = READ_ONCE(event->ctx->task);
10602 	struct perf_addr_filter *filter;
10603 	struct mm_struct *mm = NULL;
10604 	unsigned int count = 0;
10605 	unsigned long flags;
10606 
10607 	/*
10608 	 * We may observe TASK_TOMBSTONE, which means that the event tear-down
10609 	 * will stop on the parent's child_mutex that our caller is also holding
10610 	 */
10611 	if (task == TASK_TOMBSTONE)
10612 		return;
10613 
10614 	if (ifh->nr_file_filters) {
10615 		mm = get_task_mm(task);
10616 		if (!mm)
10617 			goto restart;
10618 
10619 		mmap_read_lock(mm);
10620 	}
10621 
10622 	raw_spin_lock_irqsave(&ifh->lock, flags);
10623 	list_for_each_entry(filter, &ifh->list, entry) {
10624 		if (filter->path.dentry) {
10625 			/*
10626 			 * Adjust base offset if the filter is associated to a
10627 			 * binary that needs to be mapped:
10628 			 */
10629 			event->addr_filter_ranges[count].start = 0;
10630 			event->addr_filter_ranges[count].size = 0;
10631 
10632 			perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
10633 		} else {
10634 			event->addr_filter_ranges[count].start = filter->offset;
10635 			event->addr_filter_ranges[count].size  = filter->size;
10636 		}
10637 
10638 		count++;
10639 	}
10640 
10641 	event->addr_filters_gen++;
10642 	raw_spin_unlock_irqrestore(&ifh->lock, flags);
10643 
10644 	if (ifh->nr_file_filters) {
10645 		mmap_read_unlock(mm);
10646 
10647 		mmput(mm);
10648 	}
10649 
10650 restart:
10651 	perf_event_stop(event, 1);
10652 }
10653 
10654 /*
10655  * Address range filtering: limiting the data to certain
10656  * instruction address ranges. Filters are ioctl()ed to us from
10657  * userspace as ascii strings.
10658  *
10659  * Filter string format:
10660  *
10661  * ACTION RANGE_SPEC
10662  * where ACTION is one of the
10663  *  * "filter": limit the trace to this region
10664  *  * "start": start tracing from this address
10665  *  * "stop": stop tracing at this address/region;
10666  * RANGE_SPEC is
10667  *  * for kernel addresses: <start address>[/<size>]
10668  *  * for object files:     <start address>[/<size>]@</path/to/object/file>
10669  *
10670  * if <size> is not specified or is zero, the range is treated as a single
10671  * address; not valid for ACTION=="filter".
10672  */
10673 enum {
10674 	IF_ACT_NONE = -1,
10675 	IF_ACT_FILTER,
10676 	IF_ACT_START,
10677 	IF_ACT_STOP,
10678 	IF_SRC_FILE,
10679 	IF_SRC_KERNEL,
10680 	IF_SRC_FILEADDR,
10681 	IF_SRC_KERNELADDR,
10682 };
10683 
10684 enum {
10685 	IF_STATE_ACTION = 0,
10686 	IF_STATE_SOURCE,
10687 	IF_STATE_END,
10688 };
10689 
10690 static const match_table_t if_tokens = {
10691 	{ IF_ACT_FILTER,	"filter" },
10692 	{ IF_ACT_START,		"start" },
10693 	{ IF_ACT_STOP,		"stop" },
10694 	{ IF_SRC_FILE,		"%u/%u@%s" },
10695 	{ IF_SRC_KERNEL,	"%u/%u" },
10696 	{ IF_SRC_FILEADDR,	"%u@%s" },
10697 	{ IF_SRC_KERNELADDR,	"%u" },
10698 	{ IF_ACT_NONE,		NULL },
10699 };
10700 
10701 /*
10702  * Address filter string parser
10703  */
10704 static int
10705 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
10706 			     struct list_head *filters)
10707 {
10708 	struct perf_addr_filter *filter = NULL;
10709 	char *start, *orig, *filename = NULL;
10710 	substring_t args[MAX_OPT_ARGS];
10711 	int state = IF_STATE_ACTION, token;
10712 	unsigned int kernel = 0;
10713 	int ret = -EINVAL;
10714 
10715 	orig = fstr = kstrdup(fstr, GFP_KERNEL);
10716 	if (!fstr)
10717 		return -ENOMEM;
10718 
10719 	while ((start = strsep(&fstr, " ,\n")) != NULL) {
10720 		static const enum perf_addr_filter_action_t actions[] = {
10721 			[IF_ACT_FILTER]	= PERF_ADDR_FILTER_ACTION_FILTER,
10722 			[IF_ACT_START]	= PERF_ADDR_FILTER_ACTION_START,
10723 			[IF_ACT_STOP]	= PERF_ADDR_FILTER_ACTION_STOP,
10724 		};
10725 		ret = -EINVAL;
10726 
10727 		if (!*start)
10728 			continue;
10729 
10730 		/* filter definition begins */
10731 		if (state == IF_STATE_ACTION) {
10732 			filter = perf_addr_filter_new(event, filters);
10733 			if (!filter)
10734 				goto fail;
10735 		}
10736 
10737 		token = match_token(start, if_tokens, args);
10738 		switch (token) {
10739 		case IF_ACT_FILTER:
10740 		case IF_ACT_START:
10741 		case IF_ACT_STOP:
10742 			if (state != IF_STATE_ACTION)
10743 				goto fail;
10744 
10745 			filter->action = actions[token];
10746 			state = IF_STATE_SOURCE;
10747 			break;
10748 
10749 		case IF_SRC_KERNELADDR:
10750 		case IF_SRC_KERNEL:
10751 			kernel = 1;
10752 			fallthrough;
10753 
10754 		case IF_SRC_FILEADDR:
10755 		case IF_SRC_FILE:
10756 			if (state != IF_STATE_SOURCE)
10757 				goto fail;
10758 
10759 			*args[0].to = 0;
10760 			ret = kstrtoul(args[0].from, 0, &filter->offset);
10761 			if (ret)
10762 				goto fail;
10763 
10764 			if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
10765 				*args[1].to = 0;
10766 				ret = kstrtoul(args[1].from, 0, &filter->size);
10767 				if (ret)
10768 					goto fail;
10769 			}
10770 
10771 			if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
10772 				int fpos = token == IF_SRC_FILE ? 2 : 1;
10773 
10774 				kfree(filename);
10775 				filename = match_strdup(&args[fpos]);
10776 				if (!filename) {
10777 					ret = -ENOMEM;
10778 					goto fail;
10779 				}
10780 			}
10781 
10782 			state = IF_STATE_END;
10783 			break;
10784 
10785 		default:
10786 			goto fail;
10787 		}
10788 
10789 		/*
10790 		 * Filter definition is fully parsed, validate and install it.
10791 		 * Make sure that it doesn't contradict itself or the event's
10792 		 * attribute.
10793 		 */
10794 		if (state == IF_STATE_END) {
10795 			ret = -EINVAL;
10796 
10797 			/*
10798 			 * ACTION "filter" must have a non-zero length region
10799 			 * specified.
10800 			 */
10801 			if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
10802 			    !filter->size)
10803 				goto fail;
10804 
10805 			if (!kernel) {
10806 				if (!filename)
10807 					goto fail;
10808 
10809 				/*
10810 				 * For now, we only support file-based filters
10811 				 * in per-task events; doing so for CPU-wide
10812 				 * events requires additional context switching
10813 				 * trickery, since same object code will be
10814 				 * mapped at different virtual addresses in
10815 				 * different processes.
10816 				 */
10817 				ret = -EOPNOTSUPP;
10818 				if (!event->ctx->task)
10819 					goto fail;
10820 
10821 				/* look up the path and grab its inode */
10822 				ret = kern_path(filename, LOOKUP_FOLLOW,
10823 						&filter->path);
10824 				if (ret)
10825 					goto fail;
10826 
10827 				ret = -EINVAL;
10828 				if (!filter->path.dentry ||
10829 				    !S_ISREG(d_inode(filter->path.dentry)
10830 					     ->i_mode))
10831 					goto fail;
10832 
10833 				event->addr_filters.nr_file_filters++;
10834 			}
10835 
10836 			/* ready to consume more filters */
10837 			kfree(filename);
10838 			filename = NULL;
10839 			state = IF_STATE_ACTION;
10840 			filter = NULL;
10841 			kernel = 0;
10842 		}
10843 	}
10844 
10845 	if (state != IF_STATE_ACTION)
10846 		goto fail;
10847 
10848 	kfree(filename);
10849 	kfree(orig);
10850 
10851 	return 0;
10852 
10853 fail:
10854 	kfree(filename);
10855 	free_filters_list(filters);
10856 	kfree(orig);
10857 
10858 	return ret;
10859 }
10860 
10861 static int
10862 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
10863 {
10864 	LIST_HEAD(filters);
10865 	int ret;
10866 
10867 	/*
10868 	 * Since this is called in perf_ioctl() path, we're already holding
10869 	 * ctx::mutex.
10870 	 */
10871 	lockdep_assert_held(&event->ctx->mutex);
10872 
10873 	if (WARN_ON_ONCE(event->parent))
10874 		return -EINVAL;
10875 
10876 	ret = perf_event_parse_addr_filter(event, filter_str, &filters);
10877 	if (ret)
10878 		goto fail_clear_files;
10879 
10880 	ret = event->pmu->addr_filters_validate(&filters);
10881 	if (ret)
10882 		goto fail_free_filters;
10883 
10884 	/* remove existing filters, if any */
10885 	perf_addr_filters_splice(event, &filters);
10886 
10887 	/* install new filters */
10888 	perf_event_for_each_child(event, perf_event_addr_filters_apply);
10889 
10890 	return ret;
10891 
10892 fail_free_filters:
10893 	free_filters_list(&filters);
10894 
10895 fail_clear_files:
10896 	event->addr_filters.nr_file_filters = 0;
10897 
10898 	return ret;
10899 }
10900 
10901 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
10902 {
10903 	int ret = -EINVAL;
10904 	char *filter_str;
10905 
10906 	filter_str = strndup_user(arg, PAGE_SIZE);
10907 	if (IS_ERR(filter_str))
10908 		return PTR_ERR(filter_str);
10909 
10910 #ifdef CONFIG_EVENT_TRACING
10911 	if (perf_event_is_tracing(event)) {
10912 		struct perf_event_context *ctx = event->ctx;
10913 
10914 		/*
10915 		 * Beware, here be dragons!!
10916 		 *
10917 		 * the tracepoint muck will deadlock against ctx->mutex, but
10918 		 * the tracepoint stuff does not actually need it. So
10919 		 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
10920 		 * already have a reference on ctx.
10921 		 *
10922 		 * This can result in event getting moved to a different ctx,
10923 		 * but that does not affect the tracepoint state.
10924 		 */
10925 		mutex_unlock(&ctx->mutex);
10926 		ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
10927 		mutex_lock(&ctx->mutex);
10928 	} else
10929 #endif
10930 	if (has_addr_filter(event))
10931 		ret = perf_event_set_addr_filter(event, filter_str);
10932 
10933 	kfree(filter_str);
10934 	return ret;
10935 }
10936 
10937 /*
10938  * hrtimer based swevent callback
10939  */
10940 
10941 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
10942 {
10943 	enum hrtimer_restart ret = HRTIMER_RESTART;
10944 	struct perf_sample_data data;
10945 	struct pt_regs *regs;
10946 	struct perf_event *event;
10947 	u64 period;
10948 
10949 	event = container_of(hrtimer, struct perf_event, hw.hrtimer);
10950 
10951 	if (event->state != PERF_EVENT_STATE_ACTIVE)
10952 		return HRTIMER_NORESTART;
10953 
10954 	event->pmu->read(event);
10955 
10956 	perf_sample_data_init(&data, 0, event->hw.last_period);
10957 	regs = get_irq_regs();
10958 
10959 	if (regs && !perf_exclude_event(event, regs)) {
10960 		if (!(event->attr.exclude_idle && is_idle_task(current)))
10961 			if (__perf_event_overflow(event, 1, &data, regs))
10962 				ret = HRTIMER_NORESTART;
10963 	}
10964 
10965 	period = max_t(u64, 10000, event->hw.sample_period);
10966 	hrtimer_forward_now(hrtimer, ns_to_ktime(period));
10967 
10968 	return ret;
10969 }
10970 
10971 static void perf_swevent_start_hrtimer(struct perf_event *event)
10972 {
10973 	struct hw_perf_event *hwc = &event->hw;
10974 	s64 period;
10975 
10976 	if (!is_sampling_event(event))
10977 		return;
10978 
10979 	period = local64_read(&hwc->period_left);
10980 	if (period) {
10981 		if (period < 0)
10982 			period = 10000;
10983 
10984 		local64_set(&hwc->period_left, 0);
10985 	} else {
10986 		period = max_t(u64, 10000, hwc->sample_period);
10987 	}
10988 	hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
10989 		      HRTIMER_MODE_REL_PINNED_HARD);
10990 }
10991 
10992 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
10993 {
10994 	struct hw_perf_event *hwc = &event->hw;
10995 
10996 	if (is_sampling_event(event)) {
10997 		ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
10998 		local64_set(&hwc->period_left, ktime_to_ns(remaining));
10999 
11000 		hrtimer_cancel(&hwc->hrtimer);
11001 	}
11002 }
11003 
11004 static void perf_swevent_init_hrtimer(struct perf_event *event)
11005 {
11006 	struct hw_perf_event *hwc = &event->hw;
11007 
11008 	if (!is_sampling_event(event))
11009 		return;
11010 
11011 	hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
11012 	hwc->hrtimer.function = perf_swevent_hrtimer;
11013 
11014 	/*
11015 	 * Since hrtimers have a fixed rate, we can do a static freq->period
11016 	 * mapping and avoid the whole period adjust feedback stuff.
11017 	 */
11018 	if (event->attr.freq) {
11019 		long freq = event->attr.sample_freq;
11020 
11021 		event->attr.sample_period = NSEC_PER_SEC / freq;
11022 		hwc->sample_period = event->attr.sample_period;
11023 		local64_set(&hwc->period_left, hwc->sample_period);
11024 		hwc->last_period = hwc->sample_period;
11025 		event->attr.freq = 0;
11026 	}
11027 }
11028 
11029 /*
11030  * Software event: cpu wall time clock
11031  */
11032 
11033 static void cpu_clock_event_update(struct perf_event *event)
11034 {
11035 	s64 prev;
11036 	u64 now;
11037 
11038 	now = local_clock();
11039 	prev = local64_xchg(&event->hw.prev_count, now);
11040 	local64_add(now - prev, &event->count);
11041 }
11042 
11043 static void cpu_clock_event_start(struct perf_event *event, int flags)
11044 {
11045 	local64_set(&event->hw.prev_count, local_clock());
11046 	perf_swevent_start_hrtimer(event);
11047 }
11048 
11049 static void cpu_clock_event_stop(struct perf_event *event, int flags)
11050 {
11051 	perf_swevent_cancel_hrtimer(event);
11052 	cpu_clock_event_update(event);
11053 }
11054 
11055 static int cpu_clock_event_add(struct perf_event *event, int flags)
11056 {
11057 	if (flags & PERF_EF_START)
11058 		cpu_clock_event_start(event, flags);
11059 	perf_event_update_userpage(event);
11060 
11061 	return 0;
11062 }
11063 
11064 static void cpu_clock_event_del(struct perf_event *event, int flags)
11065 {
11066 	cpu_clock_event_stop(event, flags);
11067 }
11068 
11069 static void cpu_clock_event_read(struct perf_event *event)
11070 {
11071 	cpu_clock_event_update(event);
11072 }
11073 
11074 static int cpu_clock_event_init(struct perf_event *event)
11075 {
11076 	if (event->attr.type != PERF_TYPE_SOFTWARE)
11077 		return -ENOENT;
11078 
11079 	if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
11080 		return -ENOENT;
11081 
11082 	/*
11083 	 * no branch sampling for software events
11084 	 */
11085 	if (has_branch_stack(event))
11086 		return -EOPNOTSUPP;
11087 
11088 	perf_swevent_init_hrtimer(event);
11089 
11090 	return 0;
11091 }
11092 
11093 static struct pmu perf_cpu_clock = {
11094 	.task_ctx_nr	= perf_sw_context,
11095 
11096 	.capabilities	= PERF_PMU_CAP_NO_NMI,
11097 
11098 	.event_init	= cpu_clock_event_init,
11099 	.add		= cpu_clock_event_add,
11100 	.del		= cpu_clock_event_del,
11101 	.start		= cpu_clock_event_start,
11102 	.stop		= cpu_clock_event_stop,
11103 	.read		= cpu_clock_event_read,
11104 };
11105 
11106 /*
11107  * Software event: task time clock
11108  */
11109 
11110 static void task_clock_event_update(struct perf_event *event, u64 now)
11111 {
11112 	u64 prev;
11113 	s64 delta;
11114 
11115 	prev = local64_xchg(&event->hw.prev_count, now);
11116 	delta = now - prev;
11117 	local64_add(delta, &event->count);
11118 }
11119 
11120 static void task_clock_event_start(struct perf_event *event, int flags)
11121 {
11122 	local64_set(&event->hw.prev_count, event->ctx->time);
11123 	perf_swevent_start_hrtimer(event);
11124 }
11125 
11126 static void task_clock_event_stop(struct perf_event *event, int flags)
11127 {
11128 	perf_swevent_cancel_hrtimer(event);
11129 	task_clock_event_update(event, event->ctx->time);
11130 }
11131 
11132 static int task_clock_event_add(struct perf_event *event, int flags)
11133 {
11134 	if (flags & PERF_EF_START)
11135 		task_clock_event_start(event, flags);
11136 	perf_event_update_userpage(event);
11137 
11138 	return 0;
11139 }
11140 
11141 static void task_clock_event_del(struct perf_event *event, int flags)
11142 {
11143 	task_clock_event_stop(event, PERF_EF_UPDATE);
11144 }
11145 
11146 static void task_clock_event_read(struct perf_event *event)
11147 {
11148 	u64 now = perf_clock();
11149 	u64 delta = now - event->ctx->timestamp;
11150 	u64 time = event->ctx->time + delta;
11151 
11152 	task_clock_event_update(event, time);
11153 }
11154 
11155 static int task_clock_event_init(struct perf_event *event)
11156 {
11157 	if (event->attr.type != PERF_TYPE_SOFTWARE)
11158 		return -ENOENT;
11159 
11160 	if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
11161 		return -ENOENT;
11162 
11163 	/*
11164 	 * no branch sampling for software events
11165 	 */
11166 	if (has_branch_stack(event))
11167 		return -EOPNOTSUPP;
11168 
11169 	perf_swevent_init_hrtimer(event);
11170 
11171 	return 0;
11172 }
11173 
11174 static struct pmu perf_task_clock = {
11175 	.task_ctx_nr	= perf_sw_context,
11176 
11177 	.capabilities	= PERF_PMU_CAP_NO_NMI,
11178 
11179 	.event_init	= task_clock_event_init,
11180 	.add		= task_clock_event_add,
11181 	.del		= task_clock_event_del,
11182 	.start		= task_clock_event_start,
11183 	.stop		= task_clock_event_stop,
11184 	.read		= task_clock_event_read,
11185 };
11186 
11187 static void perf_pmu_nop_void(struct pmu *pmu)
11188 {
11189 }
11190 
11191 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
11192 {
11193 }
11194 
11195 static int perf_pmu_nop_int(struct pmu *pmu)
11196 {
11197 	return 0;
11198 }
11199 
11200 static int perf_event_nop_int(struct perf_event *event, u64 value)
11201 {
11202 	return 0;
11203 }
11204 
11205 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
11206 
11207 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
11208 {
11209 	__this_cpu_write(nop_txn_flags, flags);
11210 
11211 	if (flags & ~PERF_PMU_TXN_ADD)
11212 		return;
11213 
11214 	perf_pmu_disable(pmu);
11215 }
11216 
11217 static int perf_pmu_commit_txn(struct pmu *pmu)
11218 {
11219 	unsigned int flags = __this_cpu_read(nop_txn_flags);
11220 
11221 	__this_cpu_write(nop_txn_flags, 0);
11222 
11223 	if (flags & ~PERF_PMU_TXN_ADD)
11224 		return 0;
11225 
11226 	perf_pmu_enable(pmu);
11227 	return 0;
11228 }
11229 
11230 static void perf_pmu_cancel_txn(struct pmu *pmu)
11231 {
11232 	unsigned int flags =  __this_cpu_read(nop_txn_flags);
11233 
11234 	__this_cpu_write(nop_txn_flags, 0);
11235 
11236 	if (flags & ~PERF_PMU_TXN_ADD)
11237 		return;
11238 
11239 	perf_pmu_enable(pmu);
11240 }
11241 
11242 static int perf_event_idx_default(struct perf_event *event)
11243 {
11244 	return 0;
11245 }
11246 
11247 static void free_pmu_context(struct pmu *pmu)
11248 {
11249 	free_percpu(pmu->cpu_pmu_context);
11250 }
11251 
11252 /*
11253  * Let userspace know that this PMU supports address range filtering:
11254  */
11255 static ssize_t nr_addr_filters_show(struct device *dev,
11256 				    struct device_attribute *attr,
11257 				    char *page)
11258 {
11259 	struct pmu *pmu = dev_get_drvdata(dev);
11260 
11261 	return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
11262 }
11263 DEVICE_ATTR_RO(nr_addr_filters);
11264 
11265 static struct idr pmu_idr;
11266 
11267 static ssize_t
11268 type_show(struct device *dev, struct device_attribute *attr, char *page)
11269 {
11270 	struct pmu *pmu = dev_get_drvdata(dev);
11271 
11272 	return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->type);
11273 }
11274 static DEVICE_ATTR_RO(type);
11275 
11276 static ssize_t
11277 perf_event_mux_interval_ms_show(struct device *dev,
11278 				struct device_attribute *attr,
11279 				char *page)
11280 {
11281 	struct pmu *pmu = dev_get_drvdata(dev);
11282 
11283 	return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->hrtimer_interval_ms);
11284 }
11285 
11286 static DEFINE_MUTEX(mux_interval_mutex);
11287 
11288 static ssize_t
11289 perf_event_mux_interval_ms_store(struct device *dev,
11290 				 struct device_attribute *attr,
11291 				 const char *buf, size_t count)
11292 {
11293 	struct pmu *pmu = dev_get_drvdata(dev);
11294 	int timer, cpu, ret;
11295 
11296 	ret = kstrtoint(buf, 0, &timer);
11297 	if (ret)
11298 		return ret;
11299 
11300 	if (timer < 1)
11301 		return -EINVAL;
11302 
11303 	/* same value, noting to do */
11304 	if (timer == pmu->hrtimer_interval_ms)
11305 		return count;
11306 
11307 	mutex_lock(&mux_interval_mutex);
11308 	pmu->hrtimer_interval_ms = timer;
11309 
11310 	/* update all cpuctx for this PMU */
11311 	cpus_read_lock();
11312 	for_each_online_cpu(cpu) {
11313 		struct perf_cpu_pmu_context *cpc;
11314 		cpc = per_cpu_ptr(pmu->cpu_pmu_context, cpu);
11315 		cpc->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
11316 
11317 		cpu_function_call(cpu, perf_mux_hrtimer_restart_ipi, cpc);
11318 	}
11319 	cpus_read_unlock();
11320 	mutex_unlock(&mux_interval_mutex);
11321 
11322 	return count;
11323 }
11324 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
11325 
11326 static struct attribute *pmu_dev_attrs[] = {
11327 	&dev_attr_type.attr,
11328 	&dev_attr_perf_event_mux_interval_ms.attr,
11329 	NULL,
11330 };
11331 ATTRIBUTE_GROUPS(pmu_dev);
11332 
11333 static int pmu_bus_running;
11334 static struct bus_type pmu_bus = {
11335 	.name		= "event_source",
11336 	.dev_groups	= pmu_dev_groups,
11337 };
11338 
11339 static void pmu_dev_release(struct device *dev)
11340 {
11341 	kfree(dev);
11342 }
11343 
11344 static int pmu_dev_alloc(struct pmu *pmu)
11345 {
11346 	int ret = -ENOMEM;
11347 
11348 	pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
11349 	if (!pmu->dev)
11350 		goto out;
11351 
11352 	pmu->dev->groups = pmu->attr_groups;
11353 	device_initialize(pmu->dev);
11354 
11355 	dev_set_drvdata(pmu->dev, pmu);
11356 	pmu->dev->bus = &pmu_bus;
11357 	pmu->dev->release = pmu_dev_release;
11358 
11359 	ret = dev_set_name(pmu->dev, "%s", pmu->name);
11360 	if (ret)
11361 		goto free_dev;
11362 
11363 	ret = device_add(pmu->dev);
11364 	if (ret)
11365 		goto free_dev;
11366 
11367 	/* For PMUs with address filters, throw in an extra attribute: */
11368 	if (pmu->nr_addr_filters)
11369 		ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
11370 
11371 	if (ret)
11372 		goto del_dev;
11373 
11374 	if (pmu->attr_update)
11375 		ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
11376 
11377 	if (ret)
11378 		goto del_dev;
11379 
11380 out:
11381 	return ret;
11382 
11383 del_dev:
11384 	device_del(pmu->dev);
11385 
11386 free_dev:
11387 	put_device(pmu->dev);
11388 	goto out;
11389 }
11390 
11391 static struct lock_class_key cpuctx_mutex;
11392 static struct lock_class_key cpuctx_lock;
11393 
11394 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
11395 {
11396 	int cpu, ret, max = PERF_TYPE_MAX;
11397 
11398 	mutex_lock(&pmus_lock);
11399 	ret = -ENOMEM;
11400 	pmu->pmu_disable_count = alloc_percpu(int);
11401 	if (!pmu->pmu_disable_count)
11402 		goto unlock;
11403 
11404 	pmu->type = -1;
11405 	if (!name)
11406 		goto skip_type;
11407 	pmu->name = name;
11408 
11409 	if (type != PERF_TYPE_SOFTWARE) {
11410 		if (type >= 0)
11411 			max = type;
11412 
11413 		ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
11414 		if (ret < 0)
11415 			goto free_pdc;
11416 
11417 		WARN_ON(type >= 0 && ret != type);
11418 
11419 		type = ret;
11420 	}
11421 	pmu->type = type;
11422 
11423 	if (pmu_bus_running) {
11424 		ret = pmu_dev_alloc(pmu);
11425 		if (ret)
11426 			goto free_idr;
11427 	}
11428 
11429 skip_type:
11430 	ret = -ENOMEM;
11431 	pmu->cpu_pmu_context = alloc_percpu(struct perf_cpu_pmu_context);
11432 	if (!pmu->cpu_pmu_context)
11433 		goto free_dev;
11434 
11435 	for_each_possible_cpu(cpu) {
11436 		struct perf_cpu_pmu_context *cpc;
11437 
11438 		cpc = per_cpu_ptr(pmu->cpu_pmu_context, cpu);
11439 		__perf_init_event_pmu_context(&cpc->epc, pmu);
11440 		__perf_mux_hrtimer_init(cpc, cpu);
11441 	}
11442 
11443 	if (!pmu->start_txn) {
11444 		if (pmu->pmu_enable) {
11445 			/*
11446 			 * If we have pmu_enable/pmu_disable calls, install
11447 			 * transaction stubs that use that to try and batch
11448 			 * hardware accesses.
11449 			 */
11450 			pmu->start_txn  = perf_pmu_start_txn;
11451 			pmu->commit_txn = perf_pmu_commit_txn;
11452 			pmu->cancel_txn = perf_pmu_cancel_txn;
11453 		} else {
11454 			pmu->start_txn  = perf_pmu_nop_txn;
11455 			pmu->commit_txn = perf_pmu_nop_int;
11456 			pmu->cancel_txn = perf_pmu_nop_void;
11457 		}
11458 	}
11459 
11460 	if (!pmu->pmu_enable) {
11461 		pmu->pmu_enable  = perf_pmu_nop_void;
11462 		pmu->pmu_disable = perf_pmu_nop_void;
11463 	}
11464 
11465 	if (!pmu->check_period)
11466 		pmu->check_period = perf_event_nop_int;
11467 
11468 	if (!pmu->event_idx)
11469 		pmu->event_idx = perf_event_idx_default;
11470 
11471 	/*
11472 	 * Ensure the TYPE_SOFTWARE PMUs are at the head of the list,
11473 	 * since these cannot be in the IDR. This way the linear search
11474 	 * is fast, provided a valid software event is provided.
11475 	 */
11476 	if (type == PERF_TYPE_SOFTWARE || !name)
11477 		list_add_rcu(&pmu->entry, &pmus);
11478 	else
11479 		list_add_tail_rcu(&pmu->entry, &pmus);
11480 
11481 	atomic_set(&pmu->exclusive_cnt, 0);
11482 	ret = 0;
11483 unlock:
11484 	mutex_unlock(&pmus_lock);
11485 
11486 	return ret;
11487 
11488 free_dev:
11489 	device_del(pmu->dev);
11490 	put_device(pmu->dev);
11491 
11492 free_idr:
11493 	if (pmu->type != PERF_TYPE_SOFTWARE)
11494 		idr_remove(&pmu_idr, pmu->type);
11495 
11496 free_pdc:
11497 	free_percpu(pmu->pmu_disable_count);
11498 	goto unlock;
11499 }
11500 EXPORT_SYMBOL_GPL(perf_pmu_register);
11501 
11502 void perf_pmu_unregister(struct pmu *pmu)
11503 {
11504 	mutex_lock(&pmus_lock);
11505 	list_del_rcu(&pmu->entry);
11506 
11507 	/*
11508 	 * We dereference the pmu list under both SRCU and regular RCU, so
11509 	 * synchronize against both of those.
11510 	 */
11511 	synchronize_srcu(&pmus_srcu);
11512 	synchronize_rcu();
11513 
11514 	free_percpu(pmu->pmu_disable_count);
11515 	if (pmu->type != PERF_TYPE_SOFTWARE)
11516 		idr_remove(&pmu_idr, pmu->type);
11517 	if (pmu_bus_running) {
11518 		if (pmu->nr_addr_filters)
11519 			device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
11520 		device_del(pmu->dev);
11521 		put_device(pmu->dev);
11522 	}
11523 	free_pmu_context(pmu);
11524 	mutex_unlock(&pmus_lock);
11525 }
11526 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
11527 
11528 static inline bool has_extended_regs(struct perf_event *event)
11529 {
11530 	return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
11531 	       (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
11532 }
11533 
11534 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
11535 {
11536 	struct perf_event_context *ctx = NULL;
11537 	int ret;
11538 
11539 	if (!try_module_get(pmu->module))
11540 		return -ENODEV;
11541 
11542 	/*
11543 	 * A number of pmu->event_init() methods iterate the sibling_list to,
11544 	 * for example, validate if the group fits on the PMU. Therefore,
11545 	 * if this is a sibling event, acquire the ctx->mutex to protect
11546 	 * the sibling_list.
11547 	 */
11548 	if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
11549 		/*
11550 		 * This ctx->mutex can nest when we're called through
11551 		 * inheritance. See the perf_event_ctx_lock_nested() comment.
11552 		 */
11553 		ctx = perf_event_ctx_lock_nested(event->group_leader,
11554 						 SINGLE_DEPTH_NESTING);
11555 		BUG_ON(!ctx);
11556 	}
11557 
11558 	event->pmu = pmu;
11559 	ret = pmu->event_init(event);
11560 
11561 	if (ctx)
11562 		perf_event_ctx_unlock(event->group_leader, ctx);
11563 
11564 	if (!ret) {
11565 		if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
11566 		    has_extended_regs(event))
11567 			ret = -EOPNOTSUPP;
11568 
11569 		if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
11570 		    event_has_any_exclude_flag(event))
11571 			ret = -EINVAL;
11572 
11573 		if (ret && event->destroy)
11574 			event->destroy(event);
11575 	}
11576 
11577 	if (ret)
11578 		module_put(pmu->module);
11579 
11580 	return ret;
11581 }
11582 
11583 static struct pmu *perf_init_event(struct perf_event *event)
11584 {
11585 	bool extended_type = false;
11586 	int idx, type, ret;
11587 	struct pmu *pmu;
11588 
11589 	idx = srcu_read_lock(&pmus_srcu);
11590 
11591 	/* Try parent's PMU first: */
11592 	if (event->parent && event->parent->pmu) {
11593 		pmu = event->parent->pmu;
11594 		ret = perf_try_init_event(pmu, event);
11595 		if (!ret)
11596 			goto unlock;
11597 	}
11598 
11599 	/*
11600 	 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE
11601 	 * are often aliases for PERF_TYPE_RAW.
11602 	 */
11603 	type = event->attr.type;
11604 	if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE) {
11605 		type = event->attr.config >> PERF_PMU_TYPE_SHIFT;
11606 		if (!type) {
11607 			type = PERF_TYPE_RAW;
11608 		} else {
11609 			extended_type = true;
11610 			event->attr.config &= PERF_HW_EVENT_MASK;
11611 		}
11612 	}
11613 
11614 again:
11615 	rcu_read_lock();
11616 	pmu = idr_find(&pmu_idr, type);
11617 	rcu_read_unlock();
11618 	if (pmu) {
11619 		if (event->attr.type != type && type != PERF_TYPE_RAW &&
11620 		    !(pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE))
11621 			goto fail;
11622 
11623 		ret = perf_try_init_event(pmu, event);
11624 		if (ret == -ENOENT && event->attr.type != type && !extended_type) {
11625 			type = event->attr.type;
11626 			goto again;
11627 		}
11628 
11629 		if (ret)
11630 			pmu = ERR_PTR(ret);
11631 
11632 		goto unlock;
11633 	}
11634 
11635 	list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
11636 		ret = perf_try_init_event(pmu, event);
11637 		if (!ret)
11638 			goto unlock;
11639 
11640 		if (ret != -ENOENT) {
11641 			pmu = ERR_PTR(ret);
11642 			goto unlock;
11643 		}
11644 	}
11645 fail:
11646 	pmu = ERR_PTR(-ENOENT);
11647 unlock:
11648 	srcu_read_unlock(&pmus_srcu, idx);
11649 
11650 	return pmu;
11651 }
11652 
11653 static void attach_sb_event(struct perf_event *event)
11654 {
11655 	struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
11656 
11657 	raw_spin_lock(&pel->lock);
11658 	list_add_rcu(&event->sb_list, &pel->list);
11659 	raw_spin_unlock(&pel->lock);
11660 }
11661 
11662 /*
11663  * We keep a list of all !task (and therefore per-cpu) events
11664  * that need to receive side-band records.
11665  *
11666  * This avoids having to scan all the various PMU per-cpu contexts
11667  * looking for them.
11668  */
11669 static void account_pmu_sb_event(struct perf_event *event)
11670 {
11671 	if (is_sb_event(event))
11672 		attach_sb_event(event);
11673 }
11674 
11675 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
11676 static void account_freq_event_nohz(void)
11677 {
11678 #ifdef CONFIG_NO_HZ_FULL
11679 	/* Lock so we don't race with concurrent unaccount */
11680 	spin_lock(&nr_freq_lock);
11681 	if (atomic_inc_return(&nr_freq_events) == 1)
11682 		tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
11683 	spin_unlock(&nr_freq_lock);
11684 #endif
11685 }
11686 
11687 static void account_freq_event(void)
11688 {
11689 	if (tick_nohz_full_enabled())
11690 		account_freq_event_nohz();
11691 	else
11692 		atomic_inc(&nr_freq_events);
11693 }
11694 
11695 
11696 static void account_event(struct perf_event *event)
11697 {
11698 	bool inc = false;
11699 
11700 	if (event->parent)
11701 		return;
11702 
11703 	if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
11704 		inc = true;
11705 	if (event->attr.mmap || event->attr.mmap_data)
11706 		atomic_inc(&nr_mmap_events);
11707 	if (event->attr.build_id)
11708 		atomic_inc(&nr_build_id_events);
11709 	if (event->attr.comm)
11710 		atomic_inc(&nr_comm_events);
11711 	if (event->attr.namespaces)
11712 		atomic_inc(&nr_namespaces_events);
11713 	if (event->attr.cgroup)
11714 		atomic_inc(&nr_cgroup_events);
11715 	if (event->attr.task)
11716 		atomic_inc(&nr_task_events);
11717 	if (event->attr.freq)
11718 		account_freq_event();
11719 	if (event->attr.context_switch) {
11720 		atomic_inc(&nr_switch_events);
11721 		inc = true;
11722 	}
11723 	if (has_branch_stack(event))
11724 		inc = true;
11725 	if (is_cgroup_event(event))
11726 		inc = true;
11727 	if (event->attr.ksymbol)
11728 		atomic_inc(&nr_ksymbol_events);
11729 	if (event->attr.bpf_event)
11730 		atomic_inc(&nr_bpf_events);
11731 	if (event->attr.text_poke)
11732 		atomic_inc(&nr_text_poke_events);
11733 
11734 	if (inc) {
11735 		/*
11736 		 * We need the mutex here because static_branch_enable()
11737 		 * must complete *before* the perf_sched_count increment
11738 		 * becomes visible.
11739 		 */
11740 		if (atomic_inc_not_zero(&perf_sched_count))
11741 			goto enabled;
11742 
11743 		mutex_lock(&perf_sched_mutex);
11744 		if (!atomic_read(&perf_sched_count)) {
11745 			static_branch_enable(&perf_sched_events);
11746 			/*
11747 			 * Guarantee that all CPUs observe they key change and
11748 			 * call the perf scheduling hooks before proceeding to
11749 			 * install events that need them.
11750 			 */
11751 			synchronize_rcu();
11752 		}
11753 		/*
11754 		 * Now that we have waited for the sync_sched(), allow further
11755 		 * increments to by-pass the mutex.
11756 		 */
11757 		atomic_inc(&perf_sched_count);
11758 		mutex_unlock(&perf_sched_mutex);
11759 	}
11760 enabled:
11761 
11762 	account_pmu_sb_event(event);
11763 }
11764 
11765 /*
11766  * Allocate and initialize an event structure
11767  */
11768 static struct perf_event *
11769 perf_event_alloc(struct perf_event_attr *attr, int cpu,
11770 		 struct task_struct *task,
11771 		 struct perf_event *group_leader,
11772 		 struct perf_event *parent_event,
11773 		 perf_overflow_handler_t overflow_handler,
11774 		 void *context, int cgroup_fd)
11775 {
11776 	struct pmu *pmu;
11777 	struct perf_event *event;
11778 	struct hw_perf_event *hwc;
11779 	long err = -EINVAL;
11780 	int node;
11781 
11782 	if ((unsigned)cpu >= nr_cpu_ids) {
11783 		if (!task || cpu != -1)
11784 			return ERR_PTR(-EINVAL);
11785 	}
11786 	if (attr->sigtrap && !task) {
11787 		/* Requires a task: avoid signalling random tasks. */
11788 		return ERR_PTR(-EINVAL);
11789 	}
11790 
11791 	node = (cpu >= 0) ? cpu_to_node(cpu) : -1;
11792 	event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO,
11793 				      node);
11794 	if (!event)
11795 		return ERR_PTR(-ENOMEM);
11796 
11797 	/*
11798 	 * Single events are their own group leaders, with an
11799 	 * empty sibling list:
11800 	 */
11801 	if (!group_leader)
11802 		group_leader = event;
11803 
11804 	mutex_init(&event->child_mutex);
11805 	INIT_LIST_HEAD(&event->child_list);
11806 
11807 	INIT_LIST_HEAD(&event->event_entry);
11808 	INIT_LIST_HEAD(&event->sibling_list);
11809 	INIT_LIST_HEAD(&event->active_list);
11810 	init_event_group(event);
11811 	INIT_LIST_HEAD(&event->rb_entry);
11812 	INIT_LIST_HEAD(&event->active_entry);
11813 	INIT_LIST_HEAD(&event->addr_filters.list);
11814 	INIT_HLIST_NODE(&event->hlist_entry);
11815 
11816 
11817 	init_waitqueue_head(&event->waitq);
11818 	init_irq_work(&event->pending_irq, perf_pending_irq);
11819 	init_task_work(&event->pending_task, perf_pending_task);
11820 
11821 	mutex_init(&event->mmap_mutex);
11822 	raw_spin_lock_init(&event->addr_filters.lock);
11823 
11824 	atomic_long_set(&event->refcount, 1);
11825 	event->cpu		= cpu;
11826 	event->attr		= *attr;
11827 	event->group_leader	= group_leader;
11828 	event->pmu		= NULL;
11829 	event->oncpu		= -1;
11830 
11831 	event->parent		= parent_event;
11832 
11833 	event->ns		= get_pid_ns(task_active_pid_ns(current));
11834 	event->id		= atomic64_inc_return(&perf_event_id);
11835 
11836 	event->state		= PERF_EVENT_STATE_INACTIVE;
11837 
11838 	if (parent_event)
11839 		event->event_caps = parent_event->event_caps;
11840 
11841 	if (task) {
11842 		event->attach_state = PERF_ATTACH_TASK;
11843 		/*
11844 		 * XXX pmu::event_init needs to know what task to account to
11845 		 * and we cannot use the ctx information because we need the
11846 		 * pmu before we get a ctx.
11847 		 */
11848 		event->hw.target = get_task_struct(task);
11849 	}
11850 
11851 	event->clock = &local_clock;
11852 	if (parent_event)
11853 		event->clock = parent_event->clock;
11854 
11855 	if (!overflow_handler && parent_event) {
11856 		overflow_handler = parent_event->overflow_handler;
11857 		context = parent_event->overflow_handler_context;
11858 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
11859 		if (overflow_handler == bpf_overflow_handler) {
11860 			struct bpf_prog *prog = parent_event->prog;
11861 
11862 			bpf_prog_inc(prog);
11863 			event->prog = prog;
11864 			event->orig_overflow_handler =
11865 				parent_event->orig_overflow_handler;
11866 		}
11867 #endif
11868 	}
11869 
11870 	if (overflow_handler) {
11871 		event->overflow_handler	= overflow_handler;
11872 		event->overflow_handler_context = context;
11873 	} else if (is_write_backward(event)){
11874 		event->overflow_handler = perf_event_output_backward;
11875 		event->overflow_handler_context = NULL;
11876 	} else {
11877 		event->overflow_handler = perf_event_output_forward;
11878 		event->overflow_handler_context = NULL;
11879 	}
11880 
11881 	perf_event__state_init(event);
11882 
11883 	pmu = NULL;
11884 
11885 	hwc = &event->hw;
11886 	hwc->sample_period = attr->sample_period;
11887 	if (attr->freq && attr->sample_freq)
11888 		hwc->sample_period = 1;
11889 	hwc->last_period = hwc->sample_period;
11890 
11891 	local64_set(&hwc->period_left, hwc->sample_period);
11892 
11893 	/*
11894 	 * We currently do not support PERF_SAMPLE_READ on inherited events.
11895 	 * See perf_output_read().
11896 	 */
11897 	if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
11898 		goto err_ns;
11899 
11900 	if (!has_branch_stack(event))
11901 		event->attr.branch_sample_type = 0;
11902 
11903 	pmu = perf_init_event(event);
11904 	if (IS_ERR(pmu)) {
11905 		err = PTR_ERR(pmu);
11906 		goto err_ns;
11907 	}
11908 
11909 	/*
11910 	 * Disallow uncore-task events. Similarly, disallow uncore-cgroup
11911 	 * events (they don't make sense as the cgroup will be different
11912 	 * on other CPUs in the uncore mask).
11913 	 */
11914 	if (pmu->task_ctx_nr == perf_invalid_context && (task || cgroup_fd != -1)) {
11915 		err = -EINVAL;
11916 		goto err_pmu;
11917 	}
11918 
11919 	if (event->attr.aux_output &&
11920 	    !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
11921 		err = -EOPNOTSUPP;
11922 		goto err_pmu;
11923 	}
11924 
11925 	if (cgroup_fd != -1) {
11926 		err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
11927 		if (err)
11928 			goto err_pmu;
11929 	}
11930 
11931 	err = exclusive_event_init(event);
11932 	if (err)
11933 		goto err_pmu;
11934 
11935 	if (has_addr_filter(event)) {
11936 		event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
11937 						    sizeof(struct perf_addr_filter_range),
11938 						    GFP_KERNEL);
11939 		if (!event->addr_filter_ranges) {
11940 			err = -ENOMEM;
11941 			goto err_per_task;
11942 		}
11943 
11944 		/*
11945 		 * Clone the parent's vma offsets: they are valid until exec()
11946 		 * even if the mm is not shared with the parent.
11947 		 */
11948 		if (event->parent) {
11949 			struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
11950 
11951 			raw_spin_lock_irq(&ifh->lock);
11952 			memcpy(event->addr_filter_ranges,
11953 			       event->parent->addr_filter_ranges,
11954 			       pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
11955 			raw_spin_unlock_irq(&ifh->lock);
11956 		}
11957 
11958 		/* force hw sync on the address filters */
11959 		event->addr_filters_gen = 1;
11960 	}
11961 
11962 	if (!event->parent) {
11963 		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
11964 			err = get_callchain_buffers(attr->sample_max_stack);
11965 			if (err)
11966 				goto err_addr_filters;
11967 		}
11968 	}
11969 
11970 	err = security_perf_event_alloc(event);
11971 	if (err)
11972 		goto err_callchain_buffer;
11973 
11974 	/* symmetric to unaccount_event() in _free_event() */
11975 	account_event(event);
11976 
11977 	return event;
11978 
11979 err_callchain_buffer:
11980 	if (!event->parent) {
11981 		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
11982 			put_callchain_buffers();
11983 	}
11984 err_addr_filters:
11985 	kfree(event->addr_filter_ranges);
11986 
11987 err_per_task:
11988 	exclusive_event_destroy(event);
11989 
11990 err_pmu:
11991 	if (is_cgroup_event(event))
11992 		perf_detach_cgroup(event);
11993 	if (event->destroy)
11994 		event->destroy(event);
11995 	module_put(pmu->module);
11996 err_ns:
11997 	if (event->hw.target)
11998 		put_task_struct(event->hw.target);
11999 	call_rcu(&event->rcu_head, free_event_rcu);
12000 
12001 	return ERR_PTR(err);
12002 }
12003 
12004 static int perf_copy_attr(struct perf_event_attr __user *uattr,
12005 			  struct perf_event_attr *attr)
12006 {
12007 	u32 size;
12008 	int ret;
12009 
12010 	/* Zero the full structure, so that a short copy will be nice. */
12011 	memset(attr, 0, sizeof(*attr));
12012 
12013 	ret = get_user(size, &uattr->size);
12014 	if (ret)
12015 		return ret;
12016 
12017 	/* ABI compatibility quirk: */
12018 	if (!size)
12019 		size = PERF_ATTR_SIZE_VER0;
12020 	if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
12021 		goto err_size;
12022 
12023 	ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
12024 	if (ret) {
12025 		if (ret == -E2BIG)
12026 			goto err_size;
12027 		return ret;
12028 	}
12029 
12030 	attr->size = size;
12031 
12032 	if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
12033 		return -EINVAL;
12034 
12035 	if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
12036 		return -EINVAL;
12037 
12038 	if (attr->read_format & ~(PERF_FORMAT_MAX-1))
12039 		return -EINVAL;
12040 
12041 	if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
12042 		u64 mask = attr->branch_sample_type;
12043 
12044 		/* only using defined bits */
12045 		if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
12046 			return -EINVAL;
12047 
12048 		/* at least one branch bit must be set */
12049 		if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
12050 			return -EINVAL;
12051 
12052 		/* propagate priv level, when not set for branch */
12053 		if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
12054 
12055 			/* exclude_kernel checked on syscall entry */
12056 			if (!attr->exclude_kernel)
12057 				mask |= PERF_SAMPLE_BRANCH_KERNEL;
12058 
12059 			if (!attr->exclude_user)
12060 				mask |= PERF_SAMPLE_BRANCH_USER;
12061 
12062 			if (!attr->exclude_hv)
12063 				mask |= PERF_SAMPLE_BRANCH_HV;
12064 			/*
12065 			 * adjust user setting (for HW filter setup)
12066 			 */
12067 			attr->branch_sample_type = mask;
12068 		}
12069 		/* privileged levels capture (kernel, hv): check permissions */
12070 		if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) {
12071 			ret = perf_allow_kernel(attr);
12072 			if (ret)
12073 				return ret;
12074 		}
12075 	}
12076 
12077 	if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
12078 		ret = perf_reg_validate(attr->sample_regs_user);
12079 		if (ret)
12080 			return ret;
12081 	}
12082 
12083 	if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
12084 		if (!arch_perf_have_user_stack_dump())
12085 			return -ENOSYS;
12086 
12087 		/*
12088 		 * We have __u32 type for the size, but so far
12089 		 * we can only use __u16 as maximum due to the
12090 		 * __u16 sample size limit.
12091 		 */
12092 		if (attr->sample_stack_user >= USHRT_MAX)
12093 			return -EINVAL;
12094 		else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
12095 			return -EINVAL;
12096 	}
12097 
12098 	if (!attr->sample_max_stack)
12099 		attr->sample_max_stack = sysctl_perf_event_max_stack;
12100 
12101 	if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
12102 		ret = perf_reg_validate(attr->sample_regs_intr);
12103 
12104 #ifndef CONFIG_CGROUP_PERF
12105 	if (attr->sample_type & PERF_SAMPLE_CGROUP)
12106 		return -EINVAL;
12107 #endif
12108 	if ((attr->sample_type & PERF_SAMPLE_WEIGHT) &&
12109 	    (attr->sample_type & PERF_SAMPLE_WEIGHT_STRUCT))
12110 		return -EINVAL;
12111 
12112 	if (!attr->inherit && attr->inherit_thread)
12113 		return -EINVAL;
12114 
12115 	if (attr->remove_on_exec && attr->enable_on_exec)
12116 		return -EINVAL;
12117 
12118 	if (attr->sigtrap && !attr->remove_on_exec)
12119 		return -EINVAL;
12120 
12121 out:
12122 	return ret;
12123 
12124 err_size:
12125 	put_user(sizeof(*attr), &uattr->size);
12126 	ret = -E2BIG;
12127 	goto out;
12128 }
12129 
12130 static void mutex_lock_double(struct mutex *a, struct mutex *b)
12131 {
12132 	if (b < a)
12133 		swap(a, b);
12134 
12135 	mutex_lock(a);
12136 	mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
12137 }
12138 
12139 static int
12140 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
12141 {
12142 	struct perf_buffer *rb = NULL;
12143 	int ret = -EINVAL;
12144 
12145 	if (!output_event) {
12146 		mutex_lock(&event->mmap_mutex);
12147 		goto set;
12148 	}
12149 
12150 	/* don't allow circular references */
12151 	if (event == output_event)
12152 		goto out;
12153 
12154 	/*
12155 	 * Don't allow cross-cpu buffers
12156 	 */
12157 	if (output_event->cpu != event->cpu)
12158 		goto out;
12159 
12160 	/*
12161 	 * If its not a per-cpu rb, it must be the same task.
12162 	 */
12163 	if (output_event->cpu == -1 && output_event->ctx != event->ctx)
12164 		goto out;
12165 
12166 	/*
12167 	 * Mixing clocks in the same buffer is trouble you don't need.
12168 	 */
12169 	if (output_event->clock != event->clock)
12170 		goto out;
12171 
12172 	/*
12173 	 * Either writing ring buffer from beginning or from end.
12174 	 * Mixing is not allowed.
12175 	 */
12176 	if (is_write_backward(output_event) != is_write_backward(event))
12177 		goto out;
12178 
12179 	/*
12180 	 * If both events generate aux data, they must be on the same PMU
12181 	 */
12182 	if (has_aux(event) && has_aux(output_event) &&
12183 	    event->pmu != output_event->pmu)
12184 		goto out;
12185 
12186 	/*
12187 	 * Hold both mmap_mutex to serialize against perf_mmap_close().  Since
12188 	 * output_event is already on rb->event_list, and the list iteration
12189 	 * restarts after every removal, it is guaranteed this new event is
12190 	 * observed *OR* if output_event is already removed, it's guaranteed we
12191 	 * observe !rb->mmap_count.
12192 	 */
12193 	mutex_lock_double(&event->mmap_mutex, &output_event->mmap_mutex);
12194 set:
12195 	/* Can't redirect output if we've got an active mmap() */
12196 	if (atomic_read(&event->mmap_count))
12197 		goto unlock;
12198 
12199 	if (output_event) {
12200 		/* get the rb we want to redirect to */
12201 		rb = ring_buffer_get(output_event);
12202 		if (!rb)
12203 			goto unlock;
12204 
12205 		/* did we race against perf_mmap_close() */
12206 		if (!atomic_read(&rb->mmap_count)) {
12207 			ring_buffer_put(rb);
12208 			goto unlock;
12209 		}
12210 	}
12211 
12212 	ring_buffer_attach(event, rb);
12213 
12214 	ret = 0;
12215 unlock:
12216 	mutex_unlock(&event->mmap_mutex);
12217 	if (output_event)
12218 		mutex_unlock(&output_event->mmap_mutex);
12219 
12220 out:
12221 	return ret;
12222 }
12223 
12224 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
12225 {
12226 	bool nmi_safe = false;
12227 
12228 	switch (clk_id) {
12229 	case CLOCK_MONOTONIC:
12230 		event->clock = &ktime_get_mono_fast_ns;
12231 		nmi_safe = true;
12232 		break;
12233 
12234 	case CLOCK_MONOTONIC_RAW:
12235 		event->clock = &ktime_get_raw_fast_ns;
12236 		nmi_safe = true;
12237 		break;
12238 
12239 	case CLOCK_REALTIME:
12240 		event->clock = &ktime_get_real_ns;
12241 		break;
12242 
12243 	case CLOCK_BOOTTIME:
12244 		event->clock = &ktime_get_boottime_ns;
12245 		break;
12246 
12247 	case CLOCK_TAI:
12248 		event->clock = &ktime_get_clocktai_ns;
12249 		break;
12250 
12251 	default:
12252 		return -EINVAL;
12253 	}
12254 
12255 	if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
12256 		return -EINVAL;
12257 
12258 	return 0;
12259 }
12260 
12261 static bool
12262 perf_check_permission(struct perf_event_attr *attr, struct task_struct *task)
12263 {
12264 	unsigned int ptrace_mode = PTRACE_MODE_READ_REALCREDS;
12265 	bool is_capable = perfmon_capable();
12266 
12267 	if (attr->sigtrap) {
12268 		/*
12269 		 * perf_event_attr::sigtrap sends signals to the other task.
12270 		 * Require the current task to also have CAP_KILL.
12271 		 */
12272 		rcu_read_lock();
12273 		is_capable &= ns_capable(__task_cred(task)->user_ns, CAP_KILL);
12274 		rcu_read_unlock();
12275 
12276 		/*
12277 		 * If the required capabilities aren't available, checks for
12278 		 * ptrace permissions: upgrade to ATTACH, since sending signals
12279 		 * can effectively change the target task.
12280 		 */
12281 		ptrace_mode = PTRACE_MODE_ATTACH_REALCREDS;
12282 	}
12283 
12284 	/*
12285 	 * Preserve ptrace permission check for backwards compatibility. The
12286 	 * ptrace check also includes checks that the current task and other
12287 	 * task have matching uids, and is therefore not done here explicitly.
12288 	 */
12289 	return is_capable || ptrace_may_access(task, ptrace_mode);
12290 }
12291 
12292 /**
12293  * sys_perf_event_open - open a performance event, associate it to a task/cpu
12294  *
12295  * @attr_uptr:	event_id type attributes for monitoring/sampling
12296  * @pid:		target pid
12297  * @cpu:		target cpu
12298  * @group_fd:		group leader event fd
12299  * @flags:		perf event open flags
12300  */
12301 SYSCALL_DEFINE5(perf_event_open,
12302 		struct perf_event_attr __user *, attr_uptr,
12303 		pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
12304 {
12305 	struct perf_event *group_leader = NULL, *output_event = NULL;
12306 	struct perf_event_pmu_context *pmu_ctx;
12307 	struct perf_event *event, *sibling;
12308 	struct perf_event_attr attr;
12309 	struct perf_event_context *ctx;
12310 	struct file *event_file = NULL;
12311 	struct fd group = {NULL, 0};
12312 	struct task_struct *task = NULL;
12313 	struct pmu *pmu;
12314 	int event_fd;
12315 	int move_group = 0;
12316 	int err;
12317 	int f_flags = O_RDWR;
12318 	int cgroup_fd = -1;
12319 
12320 	/* for future expandability... */
12321 	if (flags & ~PERF_FLAG_ALL)
12322 		return -EINVAL;
12323 
12324 	err = perf_copy_attr(attr_uptr, &attr);
12325 	if (err)
12326 		return err;
12327 
12328 	/* Do we allow access to perf_event_open(2) ? */
12329 	err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
12330 	if (err)
12331 		return err;
12332 
12333 	if (!attr.exclude_kernel) {
12334 		err = perf_allow_kernel(&attr);
12335 		if (err)
12336 			return err;
12337 	}
12338 
12339 	if (attr.namespaces) {
12340 		if (!perfmon_capable())
12341 			return -EACCES;
12342 	}
12343 
12344 	if (attr.freq) {
12345 		if (attr.sample_freq > sysctl_perf_event_sample_rate)
12346 			return -EINVAL;
12347 	} else {
12348 		if (attr.sample_period & (1ULL << 63))
12349 			return -EINVAL;
12350 	}
12351 
12352 	/* Only privileged users can get physical addresses */
12353 	if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) {
12354 		err = perf_allow_kernel(&attr);
12355 		if (err)
12356 			return err;
12357 	}
12358 
12359 	/* REGS_INTR can leak data, lockdown must prevent this */
12360 	if (attr.sample_type & PERF_SAMPLE_REGS_INTR) {
12361 		err = security_locked_down(LOCKDOWN_PERF);
12362 		if (err)
12363 			return err;
12364 	}
12365 
12366 	/*
12367 	 * In cgroup mode, the pid argument is used to pass the fd
12368 	 * opened to the cgroup directory in cgroupfs. The cpu argument
12369 	 * designates the cpu on which to monitor threads from that
12370 	 * cgroup.
12371 	 */
12372 	if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
12373 		return -EINVAL;
12374 
12375 	if (flags & PERF_FLAG_FD_CLOEXEC)
12376 		f_flags |= O_CLOEXEC;
12377 
12378 	event_fd = get_unused_fd_flags(f_flags);
12379 	if (event_fd < 0)
12380 		return event_fd;
12381 
12382 	if (group_fd != -1) {
12383 		err = perf_fget_light(group_fd, &group);
12384 		if (err)
12385 			goto err_fd;
12386 		group_leader = group.file->private_data;
12387 		if (flags & PERF_FLAG_FD_OUTPUT)
12388 			output_event = group_leader;
12389 		if (flags & PERF_FLAG_FD_NO_GROUP)
12390 			group_leader = NULL;
12391 	}
12392 
12393 	if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
12394 		task = find_lively_task_by_vpid(pid);
12395 		if (IS_ERR(task)) {
12396 			err = PTR_ERR(task);
12397 			goto err_group_fd;
12398 		}
12399 	}
12400 
12401 	if (task && group_leader &&
12402 	    group_leader->attr.inherit != attr.inherit) {
12403 		err = -EINVAL;
12404 		goto err_task;
12405 	}
12406 
12407 	if (flags & PERF_FLAG_PID_CGROUP)
12408 		cgroup_fd = pid;
12409 
12410 	event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
12411 				 NULL, NULL, cgroup_fd);
12412 	if (IS_ERR(event)) {
12413 		err = PTR_ERR(event);
12414 		goto err_task;
12415 	}
12416 
12417 	if (is_sampling_event(event)) {
12418 		if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
12419 			err = -EOPNOTSUPP;
12420 			goto err_alloc;
12421 		}
12422 	}
12423 
12424 	/*
12425 	 * Special case software events and allow them to be part of
12426 	 * any hardware group.
12427 	 */
12428 	pmu = event->pmu;
12429 
12430 	if (attr.use_clockid) {
12431 		err = perf_event_set_clock(event, attr.clockid);
12432 		if (err)
12433 			goto err_alloc;
12434 	}
12435 
12436 	if (pmu->task_ctx_nr == perf_sw_context)
12437 		event->event_caps |= PERF_EV_CAP_SOFTWARE;
12438 
12439 	if (task) {
12440 		err = down_read_interruptible(&task->signal->exec_update_lock);
12441 		if (err)
12442 			goto err_alloc;
12443 
12444 		/*
12445 		 * We must hold exec_update_lock across this and any potential
12446 		 * perf_install_in_context() call for this new event to
12447 		 * serialize against exec() altering our credentials (and the
12448 		 * perf_event_exit_task() that could imply).
12449 		 */
12450 		err = -EACCES;
12451 		if (!perf_check_permission(&attr, task))
12452 			goto err_cred;
12453 	}
12454 
12455 	/*
12456 	 * Get the target context (task or percpu):
12457 	 */
12458 	ctx = find_get_context(task, event);
12459 	if (IS_ERR(ctx)) {
12460 		err = PTR_ERR(ctx);
12461 		goto err_cred;
12462 	}
12463 
12464 	mutex_lock(&ctx->mutex);
12465 
12466 	if (ctx->task == TASK_TOMBSTONE) {
12467 		err = -ESRCH;
12468 		goto err_locked;
12469 	}
12470 
12471 	if (!task) {
12472 		/*
12473 		 * Check if the @cpu we're creating an event for is online.
12474 		 *
12475 		 * We use the perf_cpu_context::ctx::mutex to serialize against
12476 		 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12477 		 */
12478 		struct perf_cpu_context *cpuctx = per_cpu_ptr(&perf_cpu_context, event->cpu);
12479 
12480 		if (!cpuctx->online) {
12481 			err = -ENODEV;
12482 			goto err_locked;
12483 		}
12484 	}
12485 
12486 	if (group_leader) {
12487 		err = -EINVAL;
12488 
12489 		/*
12490 		 * Do not allow a recursive hierarchy (this new sibling
12491 		 * becoming part of another group-sibling):
12492 		 */
12493 		if (group_leader->group_leader != group_leader)
12494 			goto err_locked;
12495 
12496 		/* All events in a group should have the same clock */
12497 		if (group_leader->clock != event->clock)
12498 			goto err_locked;
12499 
12500 		/*
12501 		 * Make sure we're both events for the same CPU;
12502 		 * grouping events for different CPUs is broken; since
12503 		 * you can never concurrently schedule them anyhow.
12504 		 */
12505 		if (group_leader->cpu != event->cpu)
12506 			goto err_locked;
12507 
12508 		/*
12509 		 * Make sure we're both on the same context; either task or cpu.
12510 		 */
12511 		if (group_leader->ctx != ctx)
12512 			goto err_locked;
12513 
12514 		/*
12515 		 * Only a group leader can be exclusive or pinned
12516 		 */
12517 		if (attr.exclusive || attr.pinned)
12518 			goto err_locked;
12519 
12520 		if (is_software_event(event) &&
12521 		    !in_software_context(group_leader)) {
12522 			/*
12523 			 * If the event is a sw event, but the group_leader
12524 			 * is on hw context.
12525 			 *
12526 			 * Allow the addition of software events to hw
12527 			 * groups, this is safe because software events
12528 			 * never fail to schedule.
12529 			 *
12530 			 * Note the comment that goes with struct
12531 			 * perf_event_pmu_context.
12532 			 */
12533 			pmu = group_leader->pmu_ctx->pmu;
12534 		} else if (!is_software_event(event)) {
12535 			if (is_software_event(group_leader) &&
12536 			    (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12537 				/*
12538 				 * In case the group is a pure software group, and we
12539 				 * try to add a hardware event, move the whole group to
12540 				 * the hardware context.
12541 				 */
12542 				move_group = 1;
12543 			}
12544 
12545 			/* Don't allow group of multiple hw events from different pmus */
12546 			if (!in_software_context(group_leader) &&
12547 			    group_leader->pmu_ctx->pmu != pmu)
12548 				goto err_locked;
12549 		}
12550 	}
12551 
12552 	/*
12553 	 * Now that we're certain of the pmu; find the pmu_ctx.
12554 	 */
12555 	pmu_ctx = find_get_pmu_context(pmu, ctx, event);
12556 	if (IS_ERR(pmu_ctx)) {
12557 		err = PTR_ERR(pmu_ctx);
12558 		goto err_locked;
12559 	}
12560 	event->pmu_ctx = pmu_ctx;
12561 
12562 	if (output_event) {
12563 		err = perf_event_set_output(event, output_event);
12564 		if (err)
12565 			goto err_context;
12566 	}
12567 
12568 	if (!perf_event_validate_size(event)) {
12569 		err = -E2BIG;
12570 		goto err_context;
12571 	}
12572 
12573 	if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) {
12574 		err = -EINVAL;
12575 		goto err_context;
12576 	}
12577 
12578 	/*
12579 	 * Must be under the same ctx::mutex as perf_install_in_context(),
12580 	 * because we need to serialize with concurrent event creation.
12581 	 */
12582 	if (!exclusive_event_installable(event, ctx)) {
12583 		err = -EBUSY;
12584 		goto err_context;
12585 	}
12586 
12587 	WARN_ON_ONCE(ctx->parent_ctx);
12588 
12589 	event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, f_flags);
12590 	if (IS_ERR(event_file)) {
12591 		err = PTR_ERR(event_file);
12592 		event_file = NULL;
12593 		goto err_context;
12594 	}
12595 
12596 	/*
12597 	 * This is the point on no return; we cannot fail hereafter. This is
12598 	 * where we start modifying current state.
12599 	 */
12600 
12601 	if (move_group) {
12602 		perf_remove_from_context(group_leader, 0);
12603 		put_pmu_ctx(group_leader->pmu_ctx);
12604 
12605 		for_each_sibling_event(sibling, group_leader) {
12606 			perf_remove_from_context(sibling, 0);
12607 			put_pmu_ctx(sibling->pmu_ctx);
12608 		}
12609 
12610 		/*
12611 		 * Install the group siblings before the group leader.
12612 		 *
12613 		 * Because a group leader will try and install the entire group
12614 		 * (through the sibling list, which is still in-tact), we can
12615 		 * end up with siblings installed in the wrong context.
12616 		 *
12617 		 * By installing siblings first we NO-OP because they're not
12618 		 * reachable through the group lists.
12619 		 */
12620 		for_each_sibling_event(sibling, group_leader) {
12621 			sibling->pmu_ctx = pmu_ctx;
12622 			get_pmu_ctx(pmu_ctx);
12623 			perf_event__state_init(sibling);
12624 			perf_install_in_context(ctx, sibling, sibling->cpu);
12625 		}
12626 
12627 		/*
12628 		 * Removing from the context ends up with disabled
12629 		 * event. What we want here is event in the initial
12630 		 * startup state, ready to be add into new context.
12631 		 */
12632 		group_leader->pmu_ctx = pmu_ctx;
12633 		get_pmu_ctx(pmu_ctx);
12634 		perf_event__state_init(group_leader);
12635 		perf_install_in_context(ctx, group_leader, group_leader->cpu);
12636 	}
12637 
12638 	/*
12639 	 * Precalculate sample_data sizes; do while holding ctx::mutex such
12640 	 * that we're serialized against further additions and before
12641 	 * perf_install_in_context() which is the point the event is active and
12642 	 * can use these values.
12643 	 */
12644 	perf_event__header_size(event);
12645 	perf_event__id_header_size(event);
12646 
12647 	event->owner = current;
12648 
12649 	perf_install_in_context(ctx, event, event->cpu);
12650 	perf_unpin_context(ctx);
12651 
12652 	mutex_unlock(&ctx->mutex);
12653 
12654 	if (task) {
12655 		up_read(&task->signal->exec_update_lock);
12656 		put_task_struct(task);
12657 	}
12658 
12659 	mutex_lock(&current->perf_event_mutex);
12660 	list_add_tail(&event->owner_entry, &current->perf_event_list);
12661 	mutex_unlock(&current->perf_event_mutex);
12662 
12663 	/*
12664 	 * Drop the reference on the group_event after placing the
12665 	 * new event on the sibling_list. This ensures destruction
12666 	 * of the group leader will find the pointer to itself in
12667 	 * perf_group_detach().
12668 	 */
12669 	fdput(group);
12670 	fd_install(event_fd, event_file);
12671 	return event_fd;
12672 
12673 err_context:
12674 	put_pmu_ctx(event->pmu_ctx);
12675 	event->pmu_ctx = NULL; /* _free_event() */
12676 err_locked:
12677 	mutex_unlock(&ctx->mutex);
12678 	perf_unpin_context(ctx);
12679 	put_ctx(ctx);
12680 err_cred:
12681 	if (task)
12682 		up_read(&task->signal->exec_update_lock);
12683 err_alloc:
12684 	free_event(event);
12685 err_task:
12686 	if (task)
12687 		put_task_struct(task);
12688 err_group_fd:
12689 	fdput(group);
12690 err_fd:
12691 	put_unused_fd(event_fd);
12692 	return err;
12693 }
12694 
12695 /**
12696  * perf_event_create_kernel_counter
12697  *
12698  * @attr: attributes of the counter to create
12699  * @cpu: cpu in which the counter is bound
12700  * @task: task to profile (NULL for percpu)
12701  * @overflow_handler: callback to trigger when we hit the event
12702  * @context: context data could be used in overflow_handler callback
12703  */
12704 struct perf_event *
12705 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
12706 				 struct task_struct *task,
12707 				 perf_overflow_handler_t overflow_handler,
12708 				 void *context)
12709 {
12710 	struct perf_event_pmu_context *pmu_ctx;
12711 	struct perf_event_context *ctx;
12712 	struct perf_event *event;
12713 	struct pmu *pmu;
12714 	int err;
12715 
12716 	/*
12717 	 * Grouping is not supported for kernel events, neither is 'AUX',
12718 	 * make sure the caller's intentions are adjusted.
12719 	 */
12720 	if (attr->aux_output)
12721 		return ERR_PTR(-EINVAL);
12722 
12723 	event = perf_event_alloc(attr, cpu, task, NULL, NULL,
12724 				 overflow_handler, context, -1);
12725 	if (IS_ERR(event)) {
12726 		err = PTR_ERR(event);
12727 		goto err;
12728 	}
12729 
12730 	/* Mark owner so we could distinguish it from user events. */
12731 	event->owner = TASK_TOMBSTONE;
12732 	pmu = event->pmu;
12733 
12734 	if (pmu->task_ctx_nr == perf_sw_context)
12735 		event->event_caps |= PERF_EV_CAP_SOFTWARE;
12736 
12737 	/*
12738 	 * Get the target context (task or percpu):
12739 	 */
12740 	ctx = find_get_context(task, event);
12741 	if (IS_ERR(ctx)) {
12742 		err = PTR_ERR(ctx);
12743 		goto err_alloc;
12744 	}
12745 
12746 	WARN_ON_ONCE(ctx->parent_ctx);
12747 	mutex_lock(&ctx->mutex);
12748 	if (ctx->task == TASK_TOMBSTONE) {
12749 		err = -ESRCH;
12750 		goto err_unlock;
12751 	}
12752 
12753 	pmu_ctx = find_get_pmu_context(pmu, ctx, event);
12754 	if (IS_ERR(pmu_ctx)) {
12755 		err = PTR_ERR(pmu_ctx);
12756 		goto err_unlock;
12757 	}
12758 	event->pmu_ctx = pmu_ctx;
12759 
12760 	if (!task) {
12761 		/*
12762 		 * Check if the @cpu we're creating an event for is online.
12763 		 *
12764 		 * We use the perf_cpu_context::ctx::mutex to serialize against
12765 		 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12766 		 */
12767 		struct perf_cpu_context *cpuctx =
12768 			container_of(ctx, struct perf_cpu_context, ctx);
12769 		if (!cpuctx->online) {
12770 			err = -ENODEV;
12771 			goto err_pmu_ctx;
12772 		}
12773 	}
12774 
12775 	if (!exclusive_event_installable(event, ctx)) {
12776 		err = -EBUSY;
12777 		goto err_pmu_ctx;
12778 	}
12779 
12780 	perf_install_in_context(ctx, event, event->cpu);
12781 	perf_unpin_context(ctx);
12782 	mutex_unlock(&ctx->mutex);
12783 
12784 	return event;
12785 
12786 err_pmu_ctx:
12787 	put_pmu_ctx(pmu_ctx);
12788 	event->pmu_ctx = NULL; /* _free_event() */
12789 err_unlock:
12790 	mutex_unlock(&ctx->mutex);
12791 	perf_unpin_context(ctx);
12792 	put_ctx(ctx);
12793 err_alloc:
12794 	free_event(event);
12795 err:
12796 	return ERR_PTR(err);
12797 }
12798 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
12799 
12800 static void __perf_pmu_remove(struct perf_event_context *ctx,
12801 			      int cpu, struct pmu *pmu,
12802 			      struct perf_event_groups *groups,
12803 			      struct list_head *events)
12804 {
12805 	struct perf_event *event, *sibling;
12806 
12807 	perf_event_groups_for_cpu_pmu(event, groups, cpu, pmu) {
12808 		perf_remove_from_context(event, 0);
12809 		put_pmu_ctx(event->pmu_ctx);
12810 		list_add(&event->migrate_entry, events);
12811 
12812 		for_each_sibling_event(sibling, event) {
12813 			perf_remove_from_context(sibling, 0);
12814 			put_pmu_ctx(sibling->pmu_ctx);
12815 			list_add(&sibling->migrate_entry, events);
12816 		}
12817 	}
12818 }
12819 
12820 static void __perf_pmu_install_event(struct pmu *pmu,
12821 				     struct perf_event_context *ctx,
12822 				     int cpu, struct perf_event *event)
12823 {
12824 	struct perf_event_pmu_context *epc;
12825 
12826 	event->cpu = cpu;
12827 	epc = find_get_pmu_context(pmu, ctx, event);
12828 	event->pmu_ctx = epc;
12829 
12830 	if (event->state >= PERF_EVENT_STATE_OFF)
12831 		event->state = PERF_EVENT_STATE_INACTIVE;
12832 	perf_install_in_context(ctx, event, cpu);
12833 }
12834 
12835 static void __perf_pmu_install(struct perf_event_context *ctx,
12836 			       int cpu, struct pmu *pmu, struct list_head *events)
12837 {
12838 	struct perf_event *event, *tmp;
12839 
12840 	/*
12841 	 * Re-instate events in 2 passes.
12842 	 *
12843 	 * Skip over group leaders and only install siblings on this first
12844 	 * pass, siblings will not get enabled without a leader, however a
12845 	 * leader will enable its siblings, even if those are still on the old
12846 	 * context.
12847 	 */
12848 	list_for_each_entry_safe(event, tmp, events, migrate_entry) {
12849 		if (event->group_leader == event)
12850 			continue;
12851 
12852 		list_del(&event->migrate_entry);
12853 		__perf_pmu_install_event(pmu, ctx, cpu, event);
12854 	}
12855 
12856 	/*
12857 	 * Once all the siblings are setup properly, install the group leaders
12858 	 * to make it go.
12859 	 */
12860 	list_for_each_entry_safe(event, tmp, events, migrate_entry) {
12861 		list_del(&event->migrate_entry);
12862 		__perf_pmu_install_event(pmu, ctx, cpu, event);
12863 	}
12864 }
12865 
12866 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
12867 {
12868 	struct perf_event_context *src_ctx, *dst_ctx;
12869 	LIST_HEAD(events);
12870 
12871 	src_ctx = &per_cpu_ptr(&perf_cpu_context, src_cpu)->ctx;
12872 	dst_ctx = &per_cpu_ptr(&perf_cpu_context, dst_cpu)->ctx;
12873 
12874 	/*
12875 	 * See perf_event_ctx_lock() for comments on the details
12876 	 * of swizzling perf_event::ctx.
12877 	 */
12878 	mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
12879 
12880 	__perf_pmu_remove(src_ctx, src_cpu, pmu, &src_ctx->pinned_groups, &events);
12881 	__perf_pmu_remove(src_ctx, src_cpu, pmu, &src_ctx->flexible_groups, &events);
12882 
12883 	/*
12884 	 * Wait for the events to quiesce before re-instating them.
12885 	 */
12886 	synchronize_rcu();
12887 
12888 	__perf_pmu_install(dst_ctx, dst_cpu, pmu, &events);
12889 
12890 	mutex_unlock(&dst_ctx->mutex);
12891 	mutex_unlock(&src_ctx->mutex);
12892 }
12893 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
12894 
12895 static void sync_child_event(struct perf_event *child_event)
12896 {
12897 	struct perf_event *parent_event = child_event->parent;
12898 	u64 child_val;
12899 
12900 	if (child_event->attr.inherit_stat) {
12901 		struct task_struct *task = child_event->ctx->task;
12902 
12903 		if (task && task != TASK_TOMBSTONE)
12904 			perf_event_read_event(child_event, task);
12905 	}
12906 
12907 	child_val = perf_event_count(child_event);
12908 
12909 	/*
12910 	 * Add back the child's count to the parent's count:
12911 	 */
12912 	atomic64_add(child_val, &parent_event->child_count);
12913 	atomic64_add(child_event->total_time_enabled,
12914 		     &parent_event->child_total_time_enabled);
12915 	atomic64_add(child_event->total_time_running,
12916 		     &parent_event->child_total_time_running);
12917 }
12918 
12919 static void
12920 perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx)
12921 {
12922 	struct perf_event *parent_event = event->parent;
12923 	unsigned long detach_flags = 0;
12924 
12925 	if (parent_event) {
12926 		/*
12927 		 * Do not destroy the 'original' grouping; because of the
12928 		 * context switch optimization the original events could've
12929 		 * ended up in a random child task.
12930 		 *
12931 		 * If we were to destroy the original group, all group related
12932 		 * operations would cease to function properly after this
12933 		 * random child dies.
12934 		 *
12935 		 * Do destroy all inherited groups, we don't care about those
12936 		 * and being thorough is better.
12937 		 */
12938 		detach_flags = DETACH_GROUP | DETACH_CHILD;
12939 		mutex_lock(&parent_event->child_mutex);
12940 	}
12941 
12942 	perf_remove_from_context(event, detach_flags);
12943 
12944 	raw_spin_lock_irq(&ctx->lock);
12945 	if (event->state > PERF_EVENT_STATE_EXIT)
12946 		perf_event_set_state(event, PERF_EVENT_STATE_EXIT);
12947 	raw_spin_unlock_irq(&ctx->lock);
12948 
12949 	/*
12950 	 * Child events can be freed.
12951 	 */
12952 	if (parent_event) {
12953 		mutex_unlock(&parent_event->child_mutex);
12954 		/*
12955 		 * Kick perf_poll() for is_event_hup();
12956 		 */
12957 		perf_event_wakeup(parent_event);
12958 		free_event(event);
12959 		put_event(parent_event);
12960 		return;
12961 	}
12962 
12963 	/*
12964 	 * Parent events are governed by their filedesc, retain them.
12965 	 */
12966 	perf_event_wakeup(event);
12967 }
12968 
12969 static void perf_event_exit_task_context(struct task_struct *child)
12970 {
12971 	struct perf_event_context *child_ctx, *clone_ctx = NULL;
12972 	struct perf_event *child_event, *next;
12973 
12974 	WARN_ON_ONCE(child != current);
12975 
12976 	child_ctx = perf_pin_task_context(child);
12977 	if (!child_ctx)
12978 		return;
12979 
12980 	/*
12981 	 * In order to reduce the amount of tricky in ctx tear-down, we hold
12982 	 * ctx::mutex over the entire thing. This serializes against almost
12983 	 * everything that wants to access the ctx.
12984 	 *
12985 	 * The exception is sys_perf_event_open() /
12986 	 * perf_event_create_kernel_count() which does find_get_context()
12987 	 * without ctx::mutex (it cannot because of the move_group double mutex
12988 	 * lock thing). See the comments in perf_install_in_context().
12989 	 */
12990 	mutex_lock(&child_ctx->mutex);
12991 
12992 	/*
12993 	 * In a single ctx::lock section, de-schedule the events and detach the
12994 	 * context from the task such that we cannot ever get it scheduled back
12995 	 * in.
12996 	 */
12997 	raw_spin_lock_irq(&child_ctx->lock);
12998 	task_ctx_sched_out(child_ctx, EVENT_ALL);
12999 
13000 	/*
13001 	 * Now that the context is inactive, destroy the task <-> ctx relation
13002 	 * and mark the context dead.
13003 	 */
13004 	RCU_INIT_POINTER(child->perf_event_ctxp, NULL);
13005 	put_ctx(child_ctx); /* cannot be last */
13006 	WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
13007 	put_task_struct(current); /* cannot be last */
13008 
13009 	clone_ctx = unclone_ctx(child_ctx);
13010 	raw_spin_unlock_irq(&child_ctx->lock);
13011 
13012 	if (clone_ctx)
13013 		put_ctx(clone_ctx);
13014 
13015 	/*
13016 	 * Report the task dead after unscheduling the events so that we
13017 	 * won't get any samples after PERF_RECORD_EXIT. We can however still
13018 	 * get a few PERF_RECORD_READ events.
13019 	 */
13020 	perf_event_task(child, child_ctx, 0);
13021 
13022 	list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
13023 		perf_event_exit_event(child_event, child_ctx);
13024 
13025 	mutex_unlock(&child_ctx->mutex);
13026 
13027 	put_ctx(child_ctx);
13028 }
13029 
13030 /*
13031  * When a child task exits, feed back event values to parent events.
13032  *
13033  * Can be called with exec_update_lock held when called from
13034  * setup_new_exec().
13035  */
13036 void perf_event_exit_task(struct task_struct *child)
13037 {
13038 	struct perf_event *event, *tmp;
13039 
13040 	mutex_lock(&child->perf_event_mutex);
13041 	list_for_each_entry_safe(event, tmp, &child->perf_event_list,
13042 				 owner_entry) {
13043 		list_del_init(&event->owner_entry);
13044 
13045 		/*
13046 		 * Ensure the list deletion is visible before we clear
13047 		 * the owner, closes a race against perf_release() where
13048 		 * we need to serialize on the owner->perf_event_mutex.
13049 		 */
13050 		smp_store_release(&event->owner, NULL);
13051 	}
13052 	mutex_unlock(&child->perf_event_mutex);
13053 
13054 	perf_event_exit_task_context(child);
13055 
13056 	/*
13057 	 * The perf_event_exit_task_context calls perf_event_task
13058 	 * with child's task_ctx, which generates EXIT events for
13059 	 * child contexts and sets child->perf_event_ctxp[] to NULL.
13060 	 * At this point we need to send EXIT events to cpu contexts.
13061 	 */
13062 	perf_event_task(child, NULL, 0);
13063 }
13064 
13065 static void perf_free_event(struct perf_event *event,
13066 			    struct perf_event_context *ctx)
13067 {
13068 	struct perf_event *parent = event->parent;
13069 
13070 	if (WARN_ON_ONCE(!parent))
13071 		return;
13072 
13073 	mutex_lock(&parent->child_mutex);
13074 	list_del_init(&event->child_list);
13075 	mutex_unlock(&parent->child_mutex);
13076 
13077 	put_event(parent);
13078 
13079 	raw_spin_lock_irq(&ctx->lock);
13080 	perf_group_detach(event);
13081 	list_del_event(event, ctx);
13082 	raw_spin_unlock_irq(&ctx->lock);
13083 	free_event(event);
13084 }
13085 
13086 /*
13087  * Free a context as created by inheritance by perf_event_init_task() below,
13088  * used by fork() in case of fail.
13089  *
13090  * Even though the task has never lived, the context and events have been
13091  * exposed through the child_list, so we must take care tearing it all down.
13092  */
13093 void perf_event_free_task(struct task_struct *task)
13094 {
13095 	struct perf_event_context *ctx;
13096 	struct perf_event *event, *tmp;
13097 
13098 	ctx = rcu_access_pointer(task->perf_event_ctxp);
13099 	if (!ctx)
13100 		return;
13101 
13102 	mutex_lock(&ctx->mutex);
13103 	raw_spin_lock_irq(&ctx->lock);
13104 	/*
13105 	 * Destroy the task <-> ctx relation and mark the context dead.
13106 	 *
13107 	 * This is important because even though the task hasn't been
13108 	 * exposed yet the context has been (through child_list).
13109 	 */
13110 	RCU_INIT_POINTER(task->perf_event_ctxp, NULL);
13111 	WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
13112 	put_task_struct(task); /* cannot be last */
13113 	raw_spin_unlock_irq(&ctx->lock);
13114 
13115 
13116 	list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
13117 		perf_free_event(event, ctx);
13118 
13119 	mutex_unlock(&ctx->mutex);
13120 
13121 	/*
13122 	 * perf_event_release_kernel() could've stolen some of our
13123 	 * child events and still have them on its free_list. In that
13124 	 * case we must wait for these events to have been freed (in
13125 	 * particular all their references to this task must've been
13126 	 * dropped).
13127 	 *
13128 	 * Without this copy_process() will unconditionally free this
13129 	 * task (irrespective of its reference count) and
13130 	 * _free_event()'s put_task_struct(event->hw.target) will be a
13131 	 * use-after-free.
13132 	 *
13133 	 * Wait for all events to drop their context reference.
13134 	 */
13135 	wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
13136 	put_ctx(ctx); /* must be last */
13137 }
13138 
13139 void perf_event_delayed_put(struct task_struct *task)
13140 {
13141 	WARN_ON_ONCE(task->perf_event_ctxp);
13142 }
13143 
13144 struct file *perf_event_get(unsigned int fd)
13145 {
13146 	struct file *file = fget(fd);
13147 	if (!file)
13148 		return ERR_PTR(-EBADF);
13149 
13150 	if (file->f_op != &perf_fops) {
13151 		fput(file);
13152 		return ERR_PTR(-EBADF);
13153 	}
13154 
13155 	return file;
13156 }
13157 
13158 const struct perf_event *perf_get_event(struct file *file)
13159 {
13160 	if (file->f_op != &perf_fops)
13161 		return ERR_PTR(-EINVAL);
13162 
13163 	return file->private_data;
13164 }
13165 
13166 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
13167 {
13168 	if (!event)
13169 		return ERR_PTR(-EINVAL);
13170 
13171 	return &event->attr;
13172 }
13173 
13174 /*
13175  * Inherit an event from parent task to child task.
13176  *
13177  * Returns:
13178  *  - valid pointer on success
13179  *  - NULL for orphaned events
13180  *  - IS_ERR() on error
13181  */
13182 static struct perf_event *
13183 inherit_event(struct perf_event *parent_event,
13184 	      struct task_struct *parent,
13185 	      struct perf_event_context *parent_ctx,
13186 	      struct task_struct *child,
13187 	      struct perf_event *group_leader,
13188 	      struct perf_event_context *child_ctx)
13189 {
13190 	enum perf_event_state parent_state = parent_event->state;
13191 	struct perf_event_pmu_context *pmu_ctx;
13192 	struct perf_event *child_event;
13193 	unsigned long flags;
13194 
13195 	/*
13196 	 * Instead of creating recursive hierarchies of events,
13197 	 * we link inherited events back to the original parent,
13198 	 * which has a filp for sure, which we use as the reference
13199 	 * count:
13200 	 */
13201 	if (parent_event->parent)
13202 		parent_event = parent_event->parent;
13203 
13204 	child_event = perf_event_alloc(&parent_event->attr,
13205 					   parent_event->cpu,
13206 					   child,
13207 					   group_leader, parent_event,
13208 					   NULL, NULL, -1);
13209 	if (IS_ERR(child_event))
13210 		return child_event;
13211 
13212 	pmu_ctx = find_get_pmu_context(child_event->pmu, child_ctx, child_event);
13213 	if (IS_ERR(pmu_ctx)) {
13214 		free_event(child_event);
13215 		return ERR_CAST(pmu_ctx);
13216 	}
13217 	child_event->pmu_ctx = pmu_ctx;
13218 
13219 	/*
13220 	 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
13221 	 * must be under the same lock in order to serialize against
13222 	 * perf_event_release_kernel(), such that either we must observe
13223 	 * is_orphaned_event() or they will observe us on the child_list.
13224 	 */
13225 	mutex_lock(&parent_event->child_mutex);
13226 	if (is_orphaned_event(parent_event) ||
13227 	    !atomic_long_inc_not_zero(&parent_event->refcount)) {
13228 		mutex_unlock(&parent_event->child_mutex);
13229 		/* task_ctx_data is freed with child_ctx */
13230 		free_event(child_event);
13231 		return NULL;
13232 	}
13233 
13234 	get_ctx(child_ctx);
13235 
13236 	/*
13237 	 * Make the child state follow the state of the parent event,
13238 	 * not its attr.disabled bit.  We hold the parent's mutex,
13239 	 * so we won't race with perf_event_{en, dis}able_family.
13240 	 */
13241 	if (parent_state >= PERF_EVENT_STATE_INACTIVE)
13242 		child_event->state = PERF_EVENT_STATE_INACTIVE;
13243 	else
13244 		child_event->state = PERF_EVENT_STATE_OFF;
13245 
13246 	if (parent_event->attr.freq) {
13247 		u64 sample_period = parent_event->hw.sample_period;
13248 		struct hw_perf_event *hwc = &child_event->hw;
13249 
13250 		hwc->sample_period = sample_period;
13251 		hwc->last_period   = sample_period;
13252 
13253 		local64_set(&hwc->period_left, sample_period);
13254 	}
13255 
13256 	child_event->ctx = child_ctx;
13257 	child_event->overflow_handler = parent_event->overflow_handler;
13258 	child_event->overflow_handler_context
13259 		= parent_event->overflow_handler_context;
13260 
13261 	/*
13262 	 * Precalculate sample_data sizes
13263 	 */
13264 	perf_event__header_size(child_event);
13265 	perf_event__id_header_size(child_event);
13266 
13267 	/*
13268 	 * Link it up in the child's context:
13269 	 */
13270 	raw_spin_lock_irqsave(&child_ctx->lock, flags);
13271 	add_event_to_ctx(child_event, child_ctx);
13272 	child_event->attach_state |= PERF_ATTACH_CHILD;
13273 	raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
13274 
13275 	/*
13276 	 * Link this into the parent event's child list
13277 	 */
13278 	list_add_tail(&child_event->child_list, &parent_event->child_list);
13279 	mutex_unlock(&parent_event->child_mutex);
13280 
13281 	return child_event;
13282 }
13283 
13284 /*
13285  * Inherits an event group.
13286  *
13287  * This will quietly suppress orphaned events; !inherit_event() is not an error.
13288  * This matches with perf_event_release_kernel() removing all child events.
13289  *
13290  * Returns:
13291  *  - 0 on success
13292  *  - <0 on error
13293  */
13294 static int inherit_group(struct perf_event *parent_event,
13295 	      struct task_struct *parent,
13296 	      struct perf_event_context *parent_ctx,
13297 	      struct task_struct *child,
13298 	      struct perf_event_context *child_ctx)
13299 {
13300 	struct perf_event *leader;
13301 	struct perf_event *sub;
13302 	struct perf_event *child_ctr;
13303 
13304 	leader = inherit_event(parent_event, parent, parent_ctx,
13305 				 child, NULL, child_ctx);
13306 	if (IS_ERR(leader))
13307 		return PTR_ERR(leader);
13308 	/*
13309 	 * @leader can be NULL here because of is_orphaned_event(). In this
13310 	 * case inherit_event() will create individual events, similar to what
13311 	 * perf_group_detach() would do anyway.
13312 	 */
13313 	for_each_sibling_event(sub, parent_event) {
13314 		child_ctr = inherit_event(sub, parent, parent_ctx,
13315 					    child, leader, child_ctx);
13316 		if (IS_ERR(child_ctr))
13317 			return PTR_ERR(child_ctr);
13318 
13319 		if (sub->aux_event == parent_event && child_ctr &&
13320 		    !perf_get_aux_event(child_ctr, leader))
13321 			return -EINVAL;
13322 	}
13323 	return 0;
13324 }
13325 
13326 /*
13327  * Creates the child task context and tries to inherit the event-group.
13328  *
13329  * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
13330  * inherited_all set when we 'fail' to inherit an orphaned event; this is
13331  * consistent with perf_event_release_kernel() removing all child events.
13332  *
13333  * Returns:
13334  *  - 0 on success
13335  *  - <0 on error
13336  */
13337 static int
13338 inherit_task_group(struct perf_event *event, struct task_struct *parent,
13339 		   struct perf_event_context *parent_ctx,
13340 		   struct task_struct *child,
13341 		   u64 clone_flags, int *inherited_all)
13342 {
13343 	struct perf_event_context *child_ctx;
13344 	int ret;
13345 
13346 	if (!event->attr.inherit ||
13347 	    (event->attr.inherit_thread && !(clone_flags & CLONE_THREAD)) ||
13348 	    /* Do not inherit if sigtrap and signal handlers were cleared. */
13349 	    (event->attr.sigtrap && (clone_flags & CLONE_CLEAR_SIGHAND))) {
13350 		*inherited_all = 0;
13351 		return 0;
13352 	}
13353 
13354 	child_ctx = child->perf_event_ctxp;
13355 	if (!child_ctx) {
13356 		/*
13357 		 * This is executed from the parent task context, so
13358 		 * inherit events that have been marked for cloning.
13359 		 * First allocate and initialize a context for the
13360 		 * child.
13361 		 */
13362 		child_ctx = alloc_perf_context(child);
13363 		if (!child_ctx)
13364 			return -ENOMEM;
13365 
13366 		child->perf_event_ctxp = child_ctx;
13367 	}
13368 
13369 	ret = inherit_group(event, parent, parent_ctx, child, child_ctx);
13370 	if (ret)
13371 		*inherited_all = 0;
13372 
13373 	return ret;
13374 }
13375 
13376 /*
13377  * Initialize the perf_event context in task_struct
13378  */
13379 static int perf_event_init_context(struct task_struct *child, u64 clone_flags)
13380 {
13381 	struct perf_event_context *child_ctx, *parent_ctx;
13382 	struct perf_event_context *cloned_ctx;
13383 	struct perf_event *event;
13384 	struct task_struct *parent = current;
13385 	int inherited_all = 1;
13386 	unsigned long flags;
13387 	int ret = 0;
13388 
13389 	if (likely(!parent->perf_event_ctxp))
13390 		return 0;
13391 
13392 	/*
13393 	 * If the parent's context is a clone, pin it so it won't get
13394 	 * swapped under us.
13395 	 */
13396 	parent_ctx = perf_pin_task_context(parent);
13397 	if (!parent_ctx)
13398 		return 0;
13399 
13400 	/*
13401 	 * No need to check if parent_ctx != NULL here; since we saw
13402 	 * it non-NULL earlier, the only reason for it to become NULL
13403 	 * is if we exit, and since we're currently in the middle of
13404 	 * a fork we can't be exiting at the same time.
13405 	 */
13406 
13407 	/*
13408 	 * Lock the parent list. No need to lock the child - not PID
13409 	 * hashed yet and not running, so nobody can access it.
13410 	 */
13411 	mutex_lock(&parent_ctx->mutex);
13412 
13413 	/*
13414 	 * We dont have to disable NMIs - we are only looking at
13415 	 * the list, not manipulating it:
13416 	 */
13417 	perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
13418 		ret = inherit_task_group(event, parent, parent_ctx,
13419 					 child, clone_flags, &inherited_all);
13420 		if (ret)
13421 			goto out_unlock;
13422 	}
13423 
13424 	/*
13425 	 * We can't hold ctx->lock when iterating the ->flexible_group list due
13426 	 * to allocations, but we need to prevent rotation because
13427 	 * rotate_ctx() will change the list from interrupt context.
13428 	 */
13429 	raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13430 	parent_ctx->rotate_disable = 1;
13431 	raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13432 
13433 	perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
13434 		ret = inherit_task_group(event, parent, parent_ctx,
13435 					 child, clone_flags, &inherited_all);
13436 		if (ret)
13437 			goto out_unlock;
13438 	}
13439 
13440 	raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13441 	parent_ctx->rotate_disable = 0;
13442 
13443 	child_ctx = child->perf_event_ctxp;
13444 
13445 	if (child_ctx && inherited_all) {
13446 		/*
13447 		 * Mark the child context as a clone of the parent
13448 		 * context, or of whatever the parent is a clone of.
13449 		 *
13450 		 * Note that if the parent is a clone, the holding of
13451 		 * parent_ctx->lock avoids it from being uncloned.
13452 		 */
13453 		cloned_ctx = parent_ctx->parent_ctx;
13454 		if (cloned_ctx) {
13455 			child_ctx->parent_ctx = cloned_ctx;
13456 			child_ctx->parent_gen = parent_ctx->parent_gen;
13457 		} else {
13458 			child_ctx->parent_ctx = parent_ctx;
13459 			child_ctx->parent_gen = parent_ctx->generation;
13460 		}
13461 		get_ctx(child_ctx->parent_ctx);
13462 	}
13463 
13464 	raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13465 out_unlock:
13466 	mutex_unlock(&parent_ctx->mutex);
13467 
13468 	perf_unpin_context(parent_ctx);
13469 	put_ctx(parent_ctx);
13470 
13471 	return ret;
13472 }
13473 
13474 /*
13475  * Initialize the perf_event context in task_struct
13476  */
13477 int perf_event_init_task(struct task_struct *child, u64 clone_flags)
13478 {
13479 	int ret;
13480 
13481 	child->perf_event_ctxp = NULL;
13482 	mutex_init(&child->perf_event_mutex);
13483 	INIT_LIST_HEAD(&child->perf_event_list);
13484 
13485 	ret = perf_event_init_context(child, clone_flags);
13486 	if (ret) {
13487 		perf_event_free_task(child);
13488 		return ret;
13489 	}
13490 
13491 	return 0;
13492 }
13493 
13494 static void __init perf_event_init_all_cpus(void)
13495 {
13496 	struct swevent_htable *swhash;
13497 	struct perf_cpu_context *cpuctx;
13498 	int cpu;
13499 
13500 	zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
13501 
13502 	for_each_possible_cpu(cpu) {
13503 		swhash = &per_cpu(swevent_htable, cpu);
13504 		mutex_init(&swhash->hlist_mutex);
13505 
13506 		INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
13507 		raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
13508 
13509 		INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
13510 
13511 		cpuctx = per_cpu_ptr(&perf_cpu_context, cpu);
13512 		__perf_event_init_context(&cpuctx->ctx);
13513 		lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
13514 		lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
13515 		cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
13516 		cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default);
13517 		cpuctx->heap = cpuctx->heap_default;
13518 	}
13519 }
13520 
13521 static void perf_swevent_init_cpu(unsigned int cpu)
13522 {
13523 	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
13524 
13525 	mutex_lock(&swhash->hlist_mutex);
13526 	if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
13527 		struct swevent_hlist *hlist;
13528 
13529 		hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
13530 		WARN_ON(!hlist);
13531 		rcu_assign_pointer(swhash->swevent_hlist, hlist);
13532 	}
13533 	mutex_unlock(&swhash->hlist_mutex);
13534 }
13535 
13536 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
13537 static void __perf_event_exit_context(void *__info)
13538 {
13539 	struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
13540 	struct perf_event_context *ctx = __info;
13541 	struct perf_event *event;
13542 
13543 	raw_spin_lock(&ctx->lock);
13544 	ctx_sched_out(ctx, EVENT_TIME);
13545 	list_for_each_entry(event, &ctx->event_list, event_entry)
13546 		__perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
13547 	raw_spin_unlock(&ctx->lock);
13548 }
13549 
13550 static void perf_event_exit_cpu_context(int cpu)
13551 {
13552 	struct perf_cpu_context *cpuctx;
13553 	struct perf_event_context *ctx;
13554 
13555 	// XXX simplify cpuctx->online
13556 	mutex_lock(&pmus_lock);
13557 	cpuctx = per_cpu_ptr(&perf_cpu_context, cpu);
13558 	ctx = &cpuctx->ctx;
13559 
13560 	mutex_lock(&ctx->mutex);
13561 	smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
13562 	cpuctx->online = 0;
13563 	mutex_unlock(&ctx->mutex);
13564 	cpumask_clear_cpu(cpu, perf_online_mask);
13565 	mutex_unlock(&pmus_lock);
13566 }
13567 #else
13568 
13569 static void perf_event_exit_cpu_context(int cpu) { }
13570 
13571 #endif
13572 
13573 int perf_event_init_cpu(unsigned int cpu)
13574 {
13575 	struct perf_cpu_context *cpuctx;
13576 	struct perf_event_context *ctx;
13577 
13578 	perf_swevent_init_cpu(cpu);
13579 
13580 	mutex_lock(&pmus_lock);
13581 	cpumask_set_cpu(cpu, perf_online_mask);
13582 	cpuctx = per_cpu_ptr(&perf_cpu_context, cpu);
13583 	ctx = &cpuctx->ctx;
13584 
13585 	mutex_lock(&ctx->mutex);
13586 	cpuctx->online = 1;
13587 	mutex_unlock(&ctx->mutex);
13588 	mutex_unlock(&pmus_lock);
13589 
13590 	return 0;
13591 }
13592 
13593 int perf_event_exit_cpu(unsigned int cpu)
13594 {
13595 	perf_event_exit_cpu_context(cpu);
13596 	return 0;
13597 }
13598 
13599 static int
13600 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
13601 {
13602 	int cpu;
13603 
13604 	for_each_online_cpu(cpu)
13605 		perf_event_exit_cpu(cpu);
13606 
13607 	return NOTIFY_OK;
13608 }
13609 
13610 /*
13611  * Run the perf reboot notifier at the very last possible moment so that
13612  * the generic watchdog code runs as long as possible.
13613  */
13614 static struct notifier_block perf_reboot_notifier = {
13615 	.notifier_call = perf_reboot,
13616 	.priority = INT_MIN,
13617 };
13618 
13619 void __init perf_event_init(void)
13620 {
13621 	int ret;
13622 
13623 	idr_init(&pmu_idr);
13624 
13625 	perf_event_init_all_cpus();
13626 	init_srcu_struct(&pmus_srcu);
13627 	perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
13628 	perf_pmu_register(&perf_cpu_clock, NULL, -1);
13629 	perf_pmu_register(&perf_task_clock, NULL, -1);
13630 	perf_tp_register();
13631 	perf_event_init_cpu(smp_processor_id());
13632 	register_reboot_notifier(&perf_reboot_notifier);
13633 
13634 	ret = init_hw_breakpoint();
13635 	WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
13636 
13637 	perf_event_cache = KMEM_CACHE(perf_event, SLAB_PANIC);
13638 
13639 	/*
13640 	 * Build time assertion that we keep the data_head at the intended
13641 	 * location.  IOW, validation we got the __reserved[] size right.
13642 	 */
13643 	BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
13644 		     != 1024);
13645 }
13646 
13647 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
13648 			      char *page)
13649 {
13650 	struct perf_pmu_events_attr *pmu_attr =
13651 		container_of(attr, struct perf_pmu_events_attr, attr);
13652 
13653 	if (pmu_attr->event_str)
13654 		return sprintf(page, "%s\n", pmu_attr->event_str);
13655 
13656 	return 0;
13657 }
13658 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
13659 
13660 static int __init perf_event_sysfs_init(void)
13661 {
13662 	struct pmu *pmu;
13663 	int ret;
13664 
13665 	mutex_lock(&pmus_lock);
13666 
13667 	ret = bus_register(&pmu_bus);
13668 	if (ret)
13669 		goto unlock;
13670 
13671 	list_for_each_entry(pmu, &pmus, entry) {
13672 		if (!pmu->name || pmu->type < 0)
13673 			continue;
13674 
13675 		ret = pmu_dev_alloc(pmu);
13676 		WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
13677 	}
13678 	pmu_bus_running = 1;
13679 	ret = 0;
13680 
13681 unlock:
13682 	mutex_unlock(&pmus_lock);
13683 
13684 	return ret;
13685 }
13686 device_initcall(perf_event_sysfs_init);
13687 
13688 #ifdef CONFIG_CGROUP_PERF
13689 static struct cgroup_subsys_state *
13690 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
13691 {
13692 	struct perf_cgroup *jc;
13693 
13694 	jc = kzalloc(sizeof(*jc), GFP_KERNEL);
13695 	if (!jc)
13696 		return ERR_PTR(-ENOMEM);
13697 
13698 	jc->info = alloc_percpu(struct perf_cgroup_info);
13699 	if (!jc->info) {
13700 		kfree(jc);
13701 		return ERR_PTR(-ENOMEM);
13702 	}
13703 
13704 	return &jc->css;
13705 }
13706 
13707 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
13708 {
13709 	struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
13710 
13711 	free_percpu(jc->info);
13712 	kfree(jc);
13713 }
13714 
13715 static int perf_cgroup_css_online(struct cgroup_subsys_state *css)
13716 {
13717 	perf_event_cgroup(css->cgroup);
13718 	return 0;
13719 }
13720 
13721 static int __perf_cgroup_move(void *info)
13722 {
13723 	struct task_struct *task = info;
13724 
13725 	preempt_disable();
13726 	perf_cgroup_switch(task);
13727 	preempt_enable();
13728 
13729 	return 0;
13730 }
13731 
13732 static void perf_cgroup_attach(struct cgroup_taskset *tset)
13733 {
13734 	struct task_struct *task;
13735 	struct cgroup_subsys_state *css;
13736 
13737 	cgroup_taskset_for_each(task, css, tset)
13738 		task_function_call(task, __perf_cgroup_move, task);
13739 }
13740 
13741 struct cgroup_subsys perf_event_cgrp_subsys = {
13742 	.css_alloc	= perf_cgroup_css_alloc,
13743 	.css_free	= perf_cgroup_css_free,
13744 	.css_online	= perf_cgroup_css_online,
13745 	.attach		= perf_cgroup_attach,
13746 	/*
13747 	 * Implicitly enable on dfl hierarchy so that perf events can
13748 	 * always be filtered by cgroup2 path as long as perf_event
13749 	 * controller is not mounted on a legacy hierarchy.
13750 	 */
13751 	.implicit_on_dfl = true,
13752 	.threaded	= true,
13753 };
13754 #endif /* CONFIG_CGROUP_PERF */
13755 
13756 DEFINE_STATIC_CALL_RET0(perf_snapshot_branch_stack, perf_snapshot_branch_stack_t);
13757