xref: /openbmc/linux/kernel/events/core.c (revision 95777591)
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/rculist.h>
32 #include <linux/uaccess.h>
33 #include <linux/syscalls.h>
34 #include <linux/anon_inodes.h>
35 #include <linux/kernel_stat.h>
36 #include <linux/cgroup.h>
37 #include <linux/perf_event.h>
38 #include <linux/trace_events.h>
39 #include <linux/hw_breakpoint.h>
40 #include <linux/mm_types.h>
41 #include <linux/module.h>
42 #include <linux/mman.h>
43 #include <linux/compat.h>
44 #include <linux/bpf.h>
45 #include <linux/filter.h>
46 #include <linux/namei.h>
47 #include <linux/parser.h>
48 #include <linux/sched/clock.h>
49 #include <linux/sched/mm.h>
50 #include <linux/proc_ns.h>
51 #include <linux/mount.h>
52 
53 #include "internal.h"
54 
55 #include <asm/irq_regs.h>
56 
57 typedef int (*remote_function_f)(void *);
58 
59 struct remote_function_call {
60 	struct task_struct	*p;
61 	remote_function_f	func;
62 	void			*info;
63 	int			ret;
64 };
65 
66 static void remote_function(void *data)
67 {
68 	struct remote_function_call *tfc = data;
69 	struct task_struct *p = tfc->p;
70 
71 	if (p) {
72 		/* -EAGAIN */
73 		if (task_cpu(p) != smp_processor_id())
74 			return;
75 
76 		/*
77 		 * Now that we're on right CPU with IRQs disabled, we can test
78 		 * if we hit the right task without races.
79 		 */
80 
81 		tfc->ret = -ESRCH; /* No such (running) process */
82 		if (p != current)
83 			return;
84 	}
85 
86 	tfc->ret = tfc->func(tfc->info);
87 }
88 
89 /**
90  * task_function_call - call a function on the cpu on which a task runs
91  * @p:		the task to evaluate
92  * @func:	the function to be called
93  * @info:	the function call argument
94  *
95  * Calls the function @func when the task is currently running. This might
96  * be on the current CPU, which just calls the function directly
97  *
98  * returns: @func return value, or
99  *	    -ESRCH  - when the process isn't running
100  *	    -EAGAIN - when the process moved away
101  */
102 static int
103 task_function_call(struct task_struct *p, remote_function_f func, void *info)
104 {
105 	struct remote_function_call data = {
106 		.p	= p,
107 		.func	= func,
108 		.info	= info,
109 		.ret	= -EAGAIN,
110 	};
111 	int ret;
112 
113 	do {
114 		ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1);
115 		if (!ret)
116 			ret = data.ret;
117 	} while (ret == -EAGAIN);
118 
119 	return ret;
120 }
121 
122 /**
123  * cpu_function_call - call a function on the cpu
124  * @func:	the function to be called
125  * @info:	the function call argument
126  *
127  * Calls the function @func on the remote cpu.
128  *
129  * returns: @func return value or -ENXIO when the cpu is offline
130  */
131 static int cpu_function_call(int cpu, remote_function_f func, void *info)
132 {
133 	struct remote_function_call data = {
134 		.p	= NULL,
135 		.func	= func,
136 		.info	= info,
137 		.ret	= -ENXIO, /* No such CPU */
138 	};
139 
140 	smp_call_function_single(cpu, remote_function, &data, 1);
141 
142 	return data.ret;
143 }
144 
145 static inline struct perf_cpu_context *
146 __get_cpu_context(struct perf_event_context *ctx)
147 {
148 	return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
149 }
150 
151 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
152 			  struct perf_event_context *ctx)
153 {
154 	raw_spin_lock(&cpuctx->ctx.lock);
155 	if (ctx)
156 		raw_spin_lock(&ctx->lock);
157 }
158 
159 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
160 			    struct perf_event_context *ctx)
161 {
162 	if (ctx)
163 		raw_spin_unlock(&ctx->lock);
164 	raw_spin_unlock(&cpuctx->ctx.lock);
165 }
166 
167 #define TASK_TOMBSTONE ((void *)-1L)
168 
169 static bool is_kernel_event(struct perf_event *event)
170 {
171 	return READ_ONCE(event->owner) == TASK_TOMBSTONE;
172 }
173 
174 /*
175  * On task ctx scheduling...
176  *
177  * When !ctx->nr_events a task context will not be scheduled. This means
178  * we can disable the scheduler hooks (for performance) without leaving
179  * pending task ctx state.
180  *
181  * This however results in two special cases:
182  *
183  *  - removing the last event from a task ctx; this is relatively straight
184  *    forward and is done in __perf_remove_from_context.
185  *
186  *  - adding the first event to a task ctx; this is tricky because we cannot
187  *    rely on ctx->is_active and therefore cannot use event_function_call().
188  *    See perf_install_in_context().
189  *
190  * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
191  */
192 
193 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
194 			struct perf_event_context *, void *);
195 
196 struct event_function_struct {
197 	struct perf_event *event;
198 	event_f func;
199 	void *data;
200 };
201 
202 static int event_function(void *info)
203 {
204 	struct event_function_struct *efs = info;
205 	struct perf_event *event = efs->event;
206 	struct perf_event_context *ctx = event->ctx;
207 	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
208 	struct perf_event_context *task_ctx = cpuctx->task_ctx;
209 	int ret = 0;
210 
211 	lockdep_assert_irqs_disabled();
212 
213 	perf_ctx_lock(cpuctx, task_ctx);
214 	/*
215 	 * Since we do the IPI call without holding ctx->lock things can have
216 	 * changed, double check we hit the task we set out to hit.
217 	 */
218 	if (ctx->task) {
219 		if (ctx->task != current) {
220 			ret = -ESRCH;
221 			goto unlock;
222 		}
223 
224 		/*
225 		 * We only use event_function_call() on established contexts,
226 		 * and event_function() is only ever called when active (or
227 		 * rather, we'll have bailed in task_function_call() or the
228 		 * above ctx->task != current test), therefore we must have
229 		 * ctx->is_active here.
230 		 */
231 		WARN_ON_ONCE(!ctx->is_active);
232 		/*
233 		 * And since we have ctx->is_active, cpuctx->task_ctx must
234 		 * match.
235 		 */
236 		WARN_ON_ONCE(task_ctx != ctx);
237 	} else {
238 		WARN_ON_ONCE(&cpuctx->ctx != ctx);
239 	}
240 
241 	efs->func(event, cpuctx, ctx, efs->data);
242 unlock:
243 	perf_ctx_unlock(cpuctx, task_ctx);
244 
245 	return ret;
246 }
247 
248 static void event_function_call(struct perf_event *event, event_f func, void *data)
249 {
250 	struct perf_event_context *ctx = event->ctx;
251 	struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
252 	struct event_function_struct efs = {
253 		.event = event,
254 		.func = func,
255 		.data = data,
256 	};
257 
258 	if (!event->parent) {
259 		/*
260 		 * If this is a !child event, we must hold ctx::mutex to
261 		 * stabilize the the event->ctx relation. See
262 		 * perf_event_ctx_lock().
263 		 */
264 		lockdep_assert_held(&ctx->mutex);
265 	}
266 
267 	if (!task) {
268 		cpu_function_call(event->cpu, event_function, &efs);
269 		return;
270 	}
271 
272 	if (task == TASK_TOMBSTONE)
273 		return;
274 
275 again:
276 	if (!task_function_call(task, event_function, &efs))
277 		return;
278 
279 	raw_spin_lock_irq(&ctx->lock);
280 	/*
281 	 * Reload the task pointer, it might have been changed by
282 	 * a concurrent perf_event_context_sched_out().
283 	 */
284 	task = ctx->task;
285 	if (task == TASK_TOMBSTONE) {
286 		raw_spin_unlock_irq(&ctx->lock);
287 		return;
288 	}
289 	if (ctx->is_active) {
290 		raw_spin_unlock_irq(&ctx->lock);
291 		goto again;
292 	}
293 	func(event, NULL, ctx, data);
294 	raw_spin_unlock_irq(&ctx->lock);
295 }
296 
297 /*
298  * Similar to event_function_call() + event_function(), but hard assumes IRQs
299  * are already disabled and we're on the right CPU.
300  */
301 static void event_function_local(struct perf_event *event, event_f func, void *data)
302 {
303 	struct perf_event_context *ctx = event->ctx;
304 	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
305 	struct task_struct *task = READ_ONCE(ctx->task);
306 	struct perf_event_context *task_ctx = NULL;
307 
308 	lockdep_assert_irqs_disabled();
309 
310 	if (task) {
311 		if (task == TASK_TOMBSTONE)
312 			return;
313 
314 		task_ctx = ctx;
315 	}
316 
317 	perf_ctx_lock(cpuctx, task_ctx);
318 
319 	task = ctx->task;
320 	if (task == TASK_TOMBSTONE)
321 		goto unlock;
322 
323 	if (task) {
324 		/*
325 		 * We must be either inactive or active and the right task,
326 		 * otherwise we're screwed, since we cannot IPI to somewhere
327 		 * else.
328 		 */
329 		if (ctx->is_active) {
330 			if (WARN_ON_ONCE(task != current))
331 				goto unlock;
332 
333 			if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
334 				goto unlock;
335 		}
336 	} else {
337 		WARN_ON_ONCE(&cpuctx->ctx != ctx);
338 	}
339 
340 	func(event, cpuctx, ctx, data);
341 unlock:
342 	perf_ctx_unlock(cpuctx, task_ctx);
343 }
344 
345 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
346 		       PERF_FLAG_FD_OUTPUT  |\
347 		       PERF_FLAG_PID_CGROUP |\
348 		       PERF_FLAG_FD_CLOEXEC)
349 
350 /*
351  * branch priv levels that need permission checks
352  */
353 #define PERF_SAMPLE_BRANCH_PERM_PLM \
354 	(PERF_SAMPLE_BRANCH_KERNEL |\
355 	 PERF_SAMPLE_BRANCH_HV)
356 
357 enum event_type_t {
358 	EVENT_FLEXIBLE = 0x1,
359 	EVENT_PINNED = 0x2,
360 	EVENT_TIME = 0x4,
361 	/* see ctx_resched() for details */
362 	EVENT_CPU = 0x8,
363 	EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
364 };
365 
366 /*
367  * perf_sched_events : >0 events exist
368  * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
369  */
370 
371 static void perf_sched_delayed(struct work_struct *work);
372 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
373 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
374 static DEFINE_MUTEX(perf_sched_mutex);
375 static atomic_t perf_sched_count;
376 
377 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
378 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
379 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
380 
381 static atomic_t nr_mmap_events __read_mostly;
382 static atomic_t nr_comm_events __read_mostly;
383 static atomic_t nr_namespaces_events __read_mostly;
384 static atomic_t nr_task_events __read_mostly;
385 static atomic_t nr_freq_events __read_mostly;
386 static atomic_t nr_switch_events __read_mostly;
387 static atomic_t nr_ksymbol_events __read_mostly;
388 static atomic_t nr_bpf_events __read_mostly;
389 
390 static LIST_HEAD(pmus);
391 static DEFINE_MUTEX(pmus_lock);
392 static struct srcu_struct pmus_srcu;
393 static cpumask_var_t perf_online_mask;
394 
395 /*
396  * perf event paranoia level:
397  *  -1 - not paranoid at all
398  *   0 - disallow raw tracepoint access for unpriv
399  *   1 - disallow cpu events for unpriv
400  *   2 - disallow kernel profiling for unpriv
401  */
402 int sysctl_perf_event_paranoid __read_mostly = 2;
403 
404 /* Minimum for 512 kiB + 1 user control page */
405 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
406 
407 /*
408  * max perf event sample rate
409  */
410 #define DEFAULT_MAX_SAMPLE_RATE		100000
411 #define DEFAULT_SAMPLE_PERIOD_NS	(NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
412 #define DEFAULT_CPU_TIME_MAX_PERCENT	25
413 
414 int sysctl_perf_event_sample_rate __read_mostly	= DEFAULT_MAX_SAMPLE_RATE;
415 
416 static int max_samples_per_tick __read_mostly	= DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
417 static int perf_sample_period_ns __read_mostly	= DEFAULT_SAMPLE_PERIOD_NS;
418 
419 static int perf_sample_allowed_ns __read_mostly =
420 	DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
421 
422 static void update_perf_cpu_limits(void)
423 {
424 	u64 tmp = perf_sample_period_ns;
425 
426 	tmp *= sysctl_perf_cpu_time_max_percent;
427 	tmp = div_u64(tmp, 100);
428 	if (!tmp)
429 		tmp = 1;
430 
431 	WRITE_ONCE(perf_sample_allowed_ns, tmp);
432 }
433 
434 static bool perf_rotate_context(struct perf_cpu_context *cpuctx);
435 
436 int perf_proc_update_handler(struct ctl_table *table, int write,
437 		void __user *buffer, size_t *lenp,
438 		loff_t *ppos)
439 {
440 	int ret;
441 	int perf_cpu = sysctl_perf_cpu_time_max_percent;
442 	/*
443 	 * If throttling is disabled don't allow the write:
444 	 */
445 	if (write && (perf_cpu == 100 || perf_cpu == 0))
446 		return -EINVAL;
447 
448 	ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
449 	if (ret || !write)
450 		return ret;
451 
452 	max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
453 	perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
454 	update_perf_cpu_limits();
455 
456 	return 0;
457 }
458 
459 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
460 
461 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
462 				void __user *buffer, size_t *lenp,
463 				loff_t *ppos)
464 {
465 	int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
466 
467 	if (ret || !write)
468 		return ret;
469 
470 	if (sysctl_perf_cpu_time_max_percent == 100 ||
471 	    sysctl_perf_cpu_time_max_percent == 0) {
472 		printk(KERN_WARNING
473 		       "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
474 		WRITE_ONCE(perf_sample_allowed_ns, 0);
475 	} else {
476 		update_perf_cpu_limits();
477 	}
478 
479 	return 0;
480 }
481 
482 /*
483  * perf samples are done in some very critical code paths (NMIs).
484  * If they take too much CPU time, the system can lock up and not
485  * get any real work done.  This will drop the sample rate when
486  * we detect that events are taking too long.
487  */
488 #define NR_ACCUMULATED_SAMPLES 128
489 static DEFINE_PER_CPU(u64, running_sample_length);
490 
491 static u64 __report_avg;
492 static u64 __report_allowed;
493 
494 static void perf_duration_warn(struct irq_work *w)
495 {
496 	printk_ratelimited(KERN_INFO
497 		"perf: interrupt took too long (%lld > %lld), lowering "
498 		"kernel.perf_event_max_sample_rate to %d\n",
499 		__report_avg, __report_allowed,
500 		sysctl_perf_event_sample_rate);
501 }
502 
503 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
504 
505 void perf_sample_event_took(u64 sample_len_ns)
506 {
507 	u64 max_len = READ_ONCE(perf_sample_allowed_ns);
508 	u64 running_len;
509 	u64 avg_len;
510 	u32 max;
511 
512 	if (max_len == 0)
513 		return;
514 
515 	/* Decay the counter by 1 average sample. */
516 	running_len = __this_cpu_read(running_sample_length);
517 	running_len -= running_len/NR_ACCUMULATED_SAMPLES;
518 	running_len += sample_len_ns;
519 	__this_cpu_write(running_sample_length, running_len);
520 
521 	/*
522 	 * Note: this will be biased artifically low until we have
523 	 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
524 	 * from having to maintain a count.
525 	 */
526 	avg_len = running_len/NR_ACCUMULATED_SAMPLES;
527 	if (avg_len <= max_len)
528 		return;
529 
530 	__report_avg = avg_len;
531 	__report_allowed = max_len;
532 
533 	/*
534 	 * Compute a throttle threshold 25% below the current duration.
535 	 */
536 	avg_len += avg_len / 4;
537 	max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
538 	if (avg_len < max)
539 		max /= (u32)avg_len;
540 	else
541 		max = 1;
542 
543 	WRITE_ONCE(perf_sample_allowed_ns, avg_len);
544 	WRITE_ONCE(max_samples_per_tick, max);
545 
546 	sysctl_perf_event_sample_rate = max * HZ;
547 	perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
548 
549 	if (!irq_work_queue(&perf_duration_work)) {
550 		early_printk("perf: interrupt took too long (%lld > %lld), lowering "
551 			     "kernel.perf_event_max_sample_rate to %d\n",
552 			     __report_avg, __report_allowed,
553 			     sysctl_perf_event_sample_rate);
554 	}
555 }
556 
557 static atomic64_t perf_event_id;
558 
559 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
560 			      enum event_type_t event_type);
561 
562 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
563 			     enum event_type_t event_type,
564 			     struct task_struct *task);
565 
566 static void update_context_time(struct perf_event_context *ctx);
567 static u64 perf_event_time(struct perf_event *event);
568 
569 void __weak perf_event_print_debug(void)	{ }
570 
571 extern __weak const char *perf_pmu_name(void)
572 {
573 	return "pmu";
574 }
575 
576 static inline u64 perf_clock(void)
577 {
578 	return local_clock();
579 }
580 
581 static inline u64 perf_event_clock(struct perf_event *event)
582 {
583 	return event->clock();
584 }
585 
586 /*
587  * State based event timekeeping...
588  *
589  * The basic idea is to use event->state to determine which (if any) time
590  * fields to increment with the current delta. This means we only need to
591  * update timestamps when we change state or when they are explicitly requested
592  * (read).
593  *
594  * Event groups make things a little more complicated, but not terribly so. The
595  * rules for a group are that if the group leader is OFF the entire group is
596  * OFF, irrespecive of what the group member states are. This results in
597  * __perf_effective_state().
598  *
599  * A futher ramification is that when a group leader flips between OFF and
600  * !OFF, we need to update all group member times.
601  *
602  *
603  * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
604  * need to make sure the relevant context time is updated before we try and
605  * update our timestamps.
606  */
607 
608 static __always_inline enum perf_event_state
609 __perf_effective_state(struct perf_event *event)
610 {
611 	struct perf_event *leader = event->group_leader;
612 
613 	if (leader->state <= PERF_EVENT_STATE_OFF)
614 		return leader->state;
615 
616 	return event->state;
617 }
618 
619 static __always_inline void
620 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
621 {
622 	enum perf_event_state state = __perf_effective_state(event);
623 	u64 delta = now - event->tstamp;
624 
625 	*enabled = event->total_time_enabled;
626 	if (state >= PERF_EVENT_STATE_INACTIVE)
627 		*enabled += delta;
628 
629 	*running = event->total_time_running;
630 	if (state >= PERF_EVENT_STATE_ACTIVE)
631 		*running += delta;
632 }
633 
634 static void perf_event_update_time(struct perf_event *event)
635 {
636 	u64 now = perf_event_time(event);
637 
638 	__perf_update_times(event, now, &event->total_time_enabled,
639 					&event->total_time_running);
640 	event->tstamp = now;
641 }
642 
643 static void perf_event_update_sibling_time(struct perf_event *leader)
644 {
645 	struct perf_event *sibling;
646 
647 	for_each_sibling_event(sibling, leader)
648 		perf_event_update_time(sibling);
649 }
650 
651 static void
652 perf_event_set_state(struct perf_event *event, enum perf_event_state state)
653 {
654 	if (event->state == state)
655 		return;
656 
657 	perf_event_update_time(event);
658 	/*
659 	 * If a group leader gets enabled/disabled all its siblings
660 	 * are affected too.
661 	 */
662 	if ((event->state < 0) ^ (state < 0))
663 		perf_event_update_sibling_time(event);
664 
665 	WRITE_ONCE(event->state, state);
666 }
667 
668 #ifdef CONFIG_CGROUP_PERF
669 
670 static inline bool
671 perf_cgroup_match(struct perf_event *event)
672 {
673 	struct perf_event_context *ctx = event->ctx;
674 	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
675 
676 	/* @event doesn't care about cgroup */
677 	if (!event->cgrp)
678 		return true;
679 
680 	/* wants specific cgroup scope but @cpuctx isn't associated with any */
681 	if (!cpuctx->cgrp)
682 		return false;
683 
684 	/*
685 	 * Cgroup scoping is recursive.  An event enabled for a cgroup is
686 	 * also enabled for all its descendant cgroups.  If @cpuctx's
687 	 * cgroup is a descendant of @event's (the test covers identity
688 	 * case), it's a match.
689 	 */
690 	return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
691 				    event->cgrp->css.cgroup);
692 }
693 
694 static inline void perf_detach_cgroup(struct perf_event *event)
695 {
696 	css_put(&event->cgrp->css);
697 	event->cgrp = NULL;
698 }
699 
700 static inline int is_cgroup_event(struct perf_event *event)
701 {
702 	return event->cgrp != NULL;
703 }
704 
705 static inline u64 perf_cgroup_event_time(struct perf_event *event)
706 {
707 	struct perf_cgroup_info *t;
708 
709 	t = per_cpu_ptr(event->cgrp->info, event->cpu);
710 	return t->time;
711 }
712 
713 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
714 {
715 	struct perf_cgroup_info *info;
716 	u64 now;
717 
718 	now = perf_clock();
719 
720 	info = this_cpu_ptr(cgrp->info);
721 
722 	info->time += now - info->timestamp;
723 	info->timestamp = now;
724 }
725 
726 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
727 {
728 	struct perf_cgroup *cgrp = cpuctx->cgrp;
729 	struct cgroup_subsys_state *css;
730 
731 	if (cgrp) {
732 		for (css = &cgrp->css; css; css = css->parent) {
733 			cgrp = container_of(css, struct perf_cgroup, css);
734 			__update_cgrp_time(cgrp);
735 		}
736 	}
737 }
738 
739 static inline void update_cgrp_time_from_event(struct perf_event *event)
740 {
741 	struct perf_cgroup *cgrp;
742 
743 	/*
744 	 * ensure we access cgroup data only when needed and
745 	 * when we know the cgroup is pinned (css_get)
746 	 */
747 	if (!is_cgroup_event(event))
748 		return;
749 
750 	cgrp = perf_cgroup_from_task(current, event->ctx);
751 	/*
752 	 * Do not update time when cgroup is not active
753 	 */
754 	if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
755 		__update_cgrp_time(event->cgrp);
756 }
757 
758 static inline void
759 perf_cgroup_set_timestamp(struct task_struct *task,
760 			  struct perf_event_context *ctx)
761 {
762 	struct perf_cgroup *cgrp;
763 	struct perf_cgroup_info *info;
764 	struct cgroup_subsys_state *css;
765 
766 	/*
767 	 * ctx->lock held by caller
768 	 * ensure we do not access cgroup data
769 	 * unless we have the cgroup pinned (css_get)
770 	 */
771 	if (!task || !ctx->nr_cgroups)
772 		return;
773 
774 	cgrp = perf_cgroup_from_task(task, ctx);
775 
776 	for (css = &cgrp->css; css; css = css->parent) {
777 		cgrp = container_of(css, struct perf_cgroup, css);
778 		info = this_cpu_ptr(cgrp->info);
779 		info->timestamp = ctx->timestamp;
780 	}
781 }
782 
783 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
784 
785 #define PERF_CGROUP_SWOUT	0x1 /* cgroup switch out every event */
786 #define PERF_CGROUP_SWIN	0x2 /* cgroup switch in events based on task */
787 
788 /*
789  * reschedule events based on the cgroup constraint of task.
790  *
791  * mode SWOUT : schedule out everything
792  * mode SWIN : schedule in based on cgroup for next
793  */
794 static void perf_cgroup_switch(struct task_struct *task, int mode)
795 {
796 	struct perf_cpu_context *cpuctx;
797 	struct list_head *list;
798 	unsigned long flags;
799 
800 	/*
801 	 * Disable interrupts and preemption to avoid this CPU's
802 	 * cgrp_cpuctx_entry to change under us.
803 	 */
804 	local_irq_save(flags);
805 
806 	list = this_cpu_ptr(&cgrp_cpuctx_list);
807 	list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
808 		WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
809 
810 		perf_ctx_lock(cpuctx, cpuctx->task_ctx);
811 		perf_pmu_disable(cpuctx->ctx.pmu);
812 
813 		if (mode & PERF_CGROUP_SWOUT) {
814 			cpu_ctx_sched_out(cpuctx, EVENT_ALL);
815 			/*
816 			 * must not be done before ctxswout due
817 			 * to event_filter_match() in event_sched_out()
818 			 */
819 			cpuctx->cgrp = NULL;
820 		}
821 
822 		if (mode & PERF_CGROUP_SWIN) {
823 			WARN_ON_ONCE(cpuctx->cgrp);
824 			/*
825 			 * set cgrp before ctxsw in to allow
826 			 * event_filter_match() to not have to pass
827 			 * task around
828 			 * we pass the cpuctx->ctx to perf_cgroup_from_task()
829 			 * because cgorup events are only per-cpu
830 			 */
831 			cpuctx->cgrp = perf_cgroup_from_task(task,
832 							     &cpuctx->ctx);
833 			cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
834 		}
835 		perf_pmu_enable(cpuctx->ctx.pmu);
836 		perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
837 	}
838 
839 	local_irq_restore(flags);
840 }
841 
842 static inline void perf_cgroup_sched_out(struct task_struct *task,
843 					 struct task_struct *next)
844 {
845 	struct perf_cgroup *cgrp1;
846 	struct perf_cgroup *cgrp2 = NULL;
847 
848 	rcu_read_lock();
849 	/*
850 	 * we come here when we know perf_cgroup_events > 0
851 	 * we do not need to pass the ctx here because we know
852 	 * we are holding the rcu lock
853 	 */
854 	cgrp1 = perf_cgroup_from_task(task, NULL);
855 	cgrp2 = perf_cgroup_from_task(next, NULL);
856 
857 	/*
858 	 * only schedule out current cgroup events if we know
859 	 * that we are switching to a different cgroup. Otherwise,
860 	 * do no touch the cgroup events.
861 	 */
862 	if (cgrp1 != cgrp2)
863 		perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
864 
865 	rcu_read_unlock();
866 }
867 
868 static inline void perf_cgroup_sched_in(struct task_struct *prev,
869 					struct task_struct *task)
870 {
871 	struct perf_cgroup *cgrp1;
872 	struct perf_cgroup *cgrp2 = NULL;
873 
874 	rcu_read_lock();
875 	/*
876 	 * we come here when we know perf_cgroup_events > 0
877 	 * we do not need to pass the ctx here because we know
878 	 * we are holding the rcu lock
879 	 */
880 	cgrp1 = perf_cgroup_from_task(task, NULL);
881 	cgrp2 = perf_cgroup_from_task(prev, NULL);
882 
883 	/*
884 	 * only need to schedule in cgroup events if we are changing
885 	 * cgroup during ctxsw. Cgroup events were not scheduled
886 	 * out of ctxsw out if that was not the case.
887 	 */
888 	if (cgrp1 != cgrp2)
889 		perf_cgroup_switch(task, PERF_CGROUP_SWIN);
890 
891 	rcu_read_unlock();
892 }
893 
894 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
895 				      struct perf_event_attr *attr,
896 				      struct perf_event *group_leader)
897 {
898 	struct perf_cgroup *cgrp;
899 	struct cgroup_subsys_state *css;
900 	struct fd f = fdget(fd);
901 	int ret = 0;
902 
903 	if (!f.file)
904 		return -EBADF;
905 
906 	css = css_tryget_online_from_dir(f.file->f_path.dentry,
907 					 &perf_event_cgrp_subsys);
908 	if (IS_ERR(css)) {
909 		ret = PTR_ERR(css);
910 		goto out;
911 	}
912 
913 	cgrp = container_of(css, struct perf_cgroup, css);
914 	event->cgrp = cgrp;
915 
916 	/*
917 	 * all events in a group must monitor
918 	 * the same cgroup because a task belongs
919 	 * to only one perf cgroup at a time
920 	 */
921 	if (group_leader && group_leader->cgrp != cgrp) {
922 		perf_detach_cgroup(event);
923 		ret = -EINVAL;
924 	}
925 out:
926 	fdput(f);
927 	return ret;
928 }
929 
930 static inline void
931 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
932 {
933 	struct perf_cgroup_info *t;
934 	t = per_cpu_ptr(event->cgrp->info, event->cpu);
935 	event->shadow_ctx_time = now - t->timestamp;
936 }
937 
938 /*
939  * Update cpuctx->cgrp so that it is set when first cgroup event is added and
940  * cleared when last cgroup event is removed.
941  */
942 static inline void
943 list_update_cgroup_event(struct perf_event *event,
944 			 struct perf_event_context *ctx, bool add)
945 {
946 	struct perf_cpu_context *cpuctx;
947 	struct list_head *cpuctx_entry;
948 
949 	if (!is_cgroup_event(event))
950 		return;
951 
952 	/*
953 	 * Because cgroup events are always per-cpu events,
954 	 * this will always be called from the right CPU.
955 	 */
956 	cpuctx = __get_cpu_context(ctx);
957 
958 	/*
959 	 * Since setting cpuctx->cgrp is conditional on the current @cgrp
960 	 * matching the event's cgroup, we must do this for every new event,
961 	 * because if the first would mismatch, the second would not try again
962 	 * and we would leave cpuctx->cgrp unset.
963 	 */
964 	if (add && !cpuctx->cgrp) {
965 		struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
966 
967 		if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
968 			cpuctx->cgrp = cgrp;
969 	}
970 
971 	if (add && ctx->nr_cgroups++)
972 		return;
973 	else if (!add && --ctx->nr_cgroups)
974 		return;
975 
976 	/* no cgroup running */
977 	if (!add)
978 		cpuctx->cgrp = NULL;
979 
980 	cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
981 	if (add)
982 		list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
983 	else
984 		list_del(cpuctx_entry);
985 }
986 
987 #else /* !CONFIG_CGROUP_PERF */
988 
989 static inline bool
990 perf_cgroup_match(struct perf_event *event)
991 {
992 	return true;
993 }
994 
995 static inline void perf_detach_cgroup(struct perf_event *event)
996 {}
997 
998 static inline int is_cgroup_event(struct perf_event *event)
999 {
1000 	return 0;
1001 }
1002 
1003 static inline void update_cgrp_time_from_event(struct perf_event *event)
1004 {
1005 }
1006 
1007 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
1008 {
1009 }
1010 
1011 static inline void perf_cgroup_sched_out(struct task_struct *task,
1012 					 struct task_struct *next)
1013 {
1014 }
1015 
1016 static inline void perf_cgroup_sched_in(struct task_struct *prev,
1017 					struct task_struct *task)
1018 {
1019 }
1020 
1021 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1022 				      struct perf_event_attr *attr,
1023 				      struct perf_event *group_leader)
1024 {
1025 	return -EINVAL;
1026 }
1027 
1028 static inline void
1029 perf_cgroup_set_timestamp(struct task_struct *task,
1030 			  struct perf_event_context *ctx)
1031 {
1032 }
1033 
1034 void
1035 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
1036 {
1037 }
1038 
1039 static inline void
1040 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
1041 {
1042 }
1043 
1044 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1045 {
1046 	return 0;
1047 }
1048 
1049 static inline void
1050 list_update_cgroup_event(struct perf_event *event,
1051 			 struct perf_event_context *ctx, bool add)
1052 {
1053 }
1054 
1055 #endif
1056 
1057 /*
1058  * set default to be dependent on timer tick just
1059  * like original code
1060  */
1061 #define PERF_CPU_HRTIMER (1000 / HZ)
1062 /*
1063  * function must be called with interrupts disabled
1064  */
1065 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1066 {
1067 	struct perf_cpu_context *cpuctx;
1068 	bool rotations;
1069 
1070 	lockdep_assert_irqs_disabled();
1071 
1072 	cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1073 	rotations = perf_rotate_context(cpuctx);
1074 
1075 	raw_spin_lock(&cpuctx->hrtimer_lock);
1076 	if (rotations)
1077 		hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1078 	else
1079 		cpuctx->hrtimer_active = 0;
1080 	raw_spin_unlock(&cpuctx->hrtimer_lock);
1081 
1082 	return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1083 }
1084 
1085 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1086 {
1087 	struct hrtimer *timer = &cpuctx->hrtimer;
1088 	struct pmu *pmu = cpuctx->ctx.pmu;
1089 	u64 interval;
1090 
1091 	/* no multiplexing needed for SW PMU */
1092 	if (pmu->task_ctx_nr == perf_sw_context)
1093 		return;
1094 
1095 	/*
1096 	 * check default is sane, if not set then force to
1097 	 * default interval (1/tick)
1098 	 */
1099 	interval = pmu->hrtimer_interval_ms;
1100 	if (interval < 1)
1101 		interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1102 
1103 	cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1104 
1105 	raw_spin_lock_init(&cpuctx->hrtimer_lock);
1106 	hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
1107 	timer->function = perf_mux_hrtimer_handler;
1108 }
1109 
1110 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1111 {
1112 	struct hrtimer *timer = &cpuctx->hrtimer;
1113 	struct pmu *pmu = cpuctx->ctx.pmu;
1114 	unsigned long flags;
1115 
1116 	/* not for SW PMU */
1117 	if (pmu->task_ctx_nr == perf_sw_context)
1118 		return 0;
1119 
1120 	raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1121 	if (!cpuctx->hrtimer_active) {
1122 		cpuctx->hrtimer_active = 1;
1123 		hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1124 		hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
1125 	}
1126 	raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1127 
1128 	return 0;
1129 }
1130 
1131 void perf_pmu_disable(struct pmu *pmu)
1132 {
1133 	int *count = this_cpu_ptr(pmu->pmu_disable_count);
1134 	if (!(*count)++)
1135 		pmu->pmu_disable(pmu);
1136 }
1137 
1138 void perf_pmu_enable(struct pmu *pmu)
1139 {
1140 	int *count = this_cpu_ptr(pmu->pmu_disable_count);
1141 	if (!--(*count))
1142 		pmu->pmu_enable(pmu);
1143 }
1144 
1145 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1146 
1147 /*
1148  * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1149  * perf_event_task_tick() are fully serialized because they're strictly cpu
1150  * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1151  * disabled, while perf_event_task_tick is called from IRQ context.
1152  */
1153 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1154 {
1155 	struct list_head *head = this_cpu_ptr(&active_ctx_list);
1156 
1157 	lockdep_assert_irqs_disabled();
1158 
1159 	WARN_ON(!list_empty(&ctx->active_ctx_list));
1160 
1161 	list_add(&ctx->active_ctx_list, head);
1162 }
1163 
1164 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1165 {
1166 	lockdep_assert_irqs_disabled();
1167 
1168 	WARN_ON(list_empty(&ctx->active_ctx_list));
1169 
1170 	list_del_init(&ctx->active_ctx_list);
1171 }
1172 
1173 static void get_ctx(struct perf_event_context *ctx)
1174 {
1175 	refcount_inc(&ctx->refcount);
1176 }
1177 
1178 static void free_ctx(struct rcu_head *head)
1179 {
1180 	struct perf_event_context *ctx;
1181 
1182 	ctx = container_of(head, struct perf_event_context, rcu_head);
1183 	kfree(ctx->task_ctx_data);
1184 	kfree(ctx);
1185 }
1186 
1187 static void put_ctx(struct perf_event_context *ctx)
1188 {
1189 	if (refcount_dec_and_test(&ctx->refcount)) {
1190 		if (ctx->parent_ctx)
1191 			put_ctx(ctx->parent_ctx);
1192 		if (ctx->task && ctx->task != TASK_TOMBSTONE)
1193 			put_task_struct(ctx->task);
1194 		call_rcu(&ctx->rcu_head, free_ctx);
1195 	}
1196 }
1197 
1198 /*
1199  * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1200  * perf_pmu_migrate_context() we need some magic.
1201  *
1202  * Those places that change perf_event::ctx will hold both
1203  * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1204  *
1205  * Lock ordering is by mutex address. There are two other sites where
1206  * perf_event_context::mutex nests and those are:
1207  *
1208  *  - perf_event_exit_task_context()	[ child , 0 ]
1209  *      perf_event_exit_event()
1210  *        put_event()			[ parent, 1 ]
1211  *
1212  *  - perf_event_init_context()		[ parent, 0 ]
1213  *      inherit_task_group()
1214  *        inherit_group()
1215  *          inherit_event()
1216  *            perf_event_alloc()
1217  *              perf_init_event()
1218  *                perf_try_init_event()	[ child , 1 ]
1219  *
1220  * While it appears there is an obvious deadlock here -- the parent and child
1221  * nesting levels are inverted between the two. This is in fact safe because
1222  * life-time rules separate them. That is an exiting task cannot fork, and a
1223  * spawning task cannot (yet) exit.
1224  *
1225  * But remember that that these are parent<->child context relations, and
1226  * migration does not affect children, therefore these two orderings should not
1227  * interact.
1228  *
1229  * The change in perf_event::ctx does not affect children (as claimed above)
1230  * because the sys_perf_event_open() case will install a new event and break
1231  * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1232  * concerned with cpuctx and that doesn't have children.
1233  *
1234  * The places that change perf_event::ctx will issue:
1235  *
1236  *   perf_remove_from_context();
1237  *   synchronize_rcu();
1238  *   perf_install_in_context();
1239  *
1240  * to affect the change. The remove_from_context() + synchronize_rcu() should
1241  * quiesce the event, after which we can install it in the new location. This
1242  * means that only external vectors (perf_fops, prctl) can perturb the event
1243  * while in transit. Therefore all such accessors should also acquire
1244  * perf_event_context::mutex to serialize against this.
1245  *
1246  * However; because event->ctx can change while we're waiting to acquire
1247  * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1248  * function.
1249  *
1250  * Lock order:
1251  *    cred_guard_mutex
1252  *	task_struct::perf_event_mutex
1253  *	  perf_event_context::mutex
1254  *	    perf_event::child_mutex;
1255  *	      perf_event_context::lock
1256  *	    perf_event::mmap_mutex
1257  *	    mmap_sem
1258  *	      perf_addr_filters_head::lock
1259  *
1260  *    cpu_hotplug_lock
1261  *      pmus_lock
1262  *	  cpuctx->mutex / perf_event_context::mutex
1263  */
1264 static struct perf_event_context *
1265 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1266 {
1267 	struct perf_event_context *ctx;
1268 
1269 again:
1270 	rcu_read_lock();
1271 	ctx = READ_ONCE(event->ctx);
1272 	if (!refcount_inc_not_zero(&ctx->refcount)) {
1273 		rcu_read_unlock();
1274 		goto again;
1275 	}
1276 	rcu_read_unlock();
1277 
1278 	mutex_lock_nested(&ctx->mutex, nesting);
1279 	if (event->ctx != ctx) {
1280 		mutex_unlock(&ctx->mutex);
1281 		put_ctx(ctx);
1282 		goto again;
1283 	}
1284 
1285 	return ctx;
1286 }
1287 
1288 static inline struct perf_event_context *
1289 perf_event_ctx_lock(struct perf_event *event)
1290 {
1291 	return perf_event_ctx_lock_nested(event, 0);
1292 }
1293 
1294 static void perf_event_ctx_unlock(struct perf_event *event,
1295 				  struct perf_event_context *ctx)
1296 {
1297 	mutex_unlock(&ctx->mutex);
1298 	put_ctx(ctx);
1299 }
1300 
1301 /*
1302  * This must be done under the ctx->lock, such as to serialize against
1303  * context_equiv(), therefore we cannot call put_ctx() since that might end up
1304  * calling scheduler related locks and ctx->lock nests inside those.
1305  */
1306 static __must_check struct perf_event_context *
1307 unclone_ctx(struct perf_event_context *ctx)
1308 {
1309 	struct perf_event_context *parent_ctx = ctx->parent_ctx;
1310 
1311 	lockdep_assert_held(&ctx->lock);
1312 
1313 	if (parent_ctx)
1314 		ctx->parent_ctx = NULL;
1315 	ctx->generation++;
1316 
1317 	return parent_ctx;
1318 }
1319 
1320 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1321 				enum pid_type type)
1322 {
1323 	u32 nr;
1324 	/*
1325 	 * only top level events have the pid namespace they were created in
1326 	 */
1327 	if (event->parent)
1328 		event = event->parent;
1329 
1330 	nr = __task_pid_nr_ns(p, type, event->ns);
1331 	/* avoid -1 if it is idle thread or runs in another ns */
1332 	if (!nr && !pid_alive(p))
1333 		nr = -1;
1334 	return nr;
1335 }
1336 
1337 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1338 {
1339 	return perf_event_pid_type(event, p, PIDTYPE_TGID);
1340 }
1341 
1342 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1343 {
1344 	return perf_event_pid_type(event, p, PIDTYPE_PID);
1345 }
1346 
1347 /*
1348  * If we inherit events we want to return the parent event id
1349  * to userspace.
1350  */
1351 static u64 primary_event_id(struct perf_event *event)
1352 {
1353 	u64 id = event->id;
1354 
1355 	if (event->parent)
1356 		id = event->parent->id;
1357 
1358 	return id;
1359 }
1360 
1361 /*
1362  * Get the perf_event_context for a task and lock it.
1363  *
1364  * This has to cope with with the fact that until it is locked,
1365  * the context could get moved to another task.
1366  */
1367 static struct perf_event_context *
1368 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1369 {
1370 	struct perf_event_context *ctx;
1371 
1372 retry:
1373 	/*
1374 	 * One of the few rules of preemptible RCU is that one cannot do
1375 	 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1376 	 * part of the read side critical section was irqs-enabled -- see
1377 	 * rcu_read_unlock_special().
1378 	 *
1379 	 * Since ctx->lock nests under rq->lock we must ensure the entire read
1380 	 * side critical section has interrupts disabled.
1381 	 */
1382 	local_irq_save(*flags);
1383 	rcu_read_lock();
1384 	ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1385 	if (ctx) {
1386 		/*
1387 		 * If this context is a clone of another, it might
1388 		 * get swapped for another underneath us by
1389 		 * perf_event_task_sched_out, though the
1390 		 * rcu_read_lock() protects us from any context
1391 		 * getting freed.  Lock the context and check if it
1392 		 * got swapped before we could get the lock, and retry
1393 		 * if so.  If we locked the right context, then it
1394 		 * can't get swapped on us any more.
1395 		 */
1396 		raw_spin_lock(&ctx->lock);
1397 		if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1398 			raw_spin_unlock(&ctx->lock);
1399 			rcu_read_unlock();
1400 			local_irq_restore(*flags);
1401 			goto retry;
1402 		}
1403 
1404 		if (ctx->task == TASK_TOMBSTONE ||
1405 		    !refcount_inc_not_zero(&ctx->refcount)) {
1406 			raw_spin_unlock(&ctx->lock);
1407 			ctx = NULL;
1408 		} else {
1409 			WARN_ON_ONCE(ctx->task != task);
1410 		}
1411 	}
1412 	rcu_read_unlock();
1413 	if (!ctx)
1414 		local_irq_restore(*flags);
1415 	return ctx;
1416 }
1417 
1418 /*
1419  * Get the context for a task and increment its pin_count so it
1420  * can't get swapped to another task.  This also increments its
1421  * reference count so that the context can't get freed.
1422  */
1423 static struct perf_event_context *
1424 perf_pin_task_context(struct task_struct *task, int ctxn)
1425 {
1426 	struct perf_event_context *ctx;
1427 	unsigned long flags;
1428 
1429 	ctx = perf_lock_task_context(task, ctxn, &flags);
1430 	if (ctx) {
1431 		++ctx->pin_count;
1432 		raw_spin_unlock_irqrestore(&ctx->lock, flags);
1433 	}
1434 	return ctx;
1435 }
1436 
1437 static void perf_unpin_context(struct perf_event_context *ctx)
1438 {
1439 	unsigned long flags;
1440 
1441 	raw_spin_lock_irqsave(&ctx->lock, flags);
1442 	--ctx->pin_count;
1443 	raw_spin_unlock_irqrestore(&ctx->lock, flags);
1444 }
1445 
1446 /*
1447  * Update the record of the current time in a context.
1448  */
1449 static void update_context_time(struct perf_event_context *ctx)
1450 {
1451 	u64 now = perf_clock();
1452 
1453 	ctx->time += now - ctx->timestamp;
1454 	ctx->timestamp = now;
1455 }
1456 
1457 static u64 perf_event_time(struct perf_event *event)
1458 {
1459 	struct perf_event_context *ctx = event->ctx;
1460 
1461 	if (is_cgroup_event(event))
1462 		return perf_cgroup_event_time(event);
1463 
1464 	return ctx ? ctx->time : 0;
1465 }
1466 
1467 static enum event_type_t get_event_type(struct perf_event *event)
1468 {
1469 	struct perf_event_context *ctx = event->ctx;
1470 	enum event_type_t event_type;
1471 
1472 	lockdep_assert_held(&ctx->lock);
1473 
1474 	/*
1475 	 * It's 'group type', really, because if our group leader is
1476 	 * pinned, so are we.
1477 	 */
1478 	if (event->group_leader != event)
1479 		event = event->group_leader;
1480 
1481 	event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1482 	if (!ctx->task)
1483 		event_type |= EVENT_CPU;
1484 
1485 	return event_type;
1486 }
1487 
1488 /*
1489  * Helper function to initialize event group nodes.
1490  */
1491 static void init_event_group(struct perf_event *event)
1492 {
1493 	RB_CLEAR_NODE(&event->group_node);
1494 	event->group_index = 0;
1495 }
1496 
1497 /*
1498  * Extract pinned or flexible groups from the context
1499  * based on event attrs bits.
1500  */
1501 static struct perf_event_groups *
1502 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1503 {
1504 	if (event->attr.pinned)
1505 		return &ctx->pinned_groups;
1506 	else
1507 		return &ctx->flexible_groups;
1508 }
1509 
1510 /*
1511  * Helper function to initializes perf_event_group trees.
1512  */
1513 static void perf_event_groups_init(struct perf_event_groups *groups)
1514 {
1515 	groups->tree = RB_ROOT;
1516 	groups->index = 0;
1517 }
1518 
1519 /*
1520  * Compare function for event groups;
1521  *
1522  * Implements complex key that first sorts by CPU and then by virtual index
1523  * which provides ordering when rotating groups for the same CPU.
1524  */
1525 static bool
1526 perf_event_groups_less(struct perf_event *left, struct perf_event *right)
1527 {
1528 	if (left->cpu < right->cpu)
1529 		return true;
1530 	if (left->cpu > right->cpu)
1531 		return false;
1532 
1533 	if (left->group_index < right->group_index)
1534 		return true;
1535 	if (left->group_index > right->group_index)
1536 		return false;
1537 
1538 	return false;
1539 }
1540 
1541 /*
1542  * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1543  * key (see perf_event_groups_less). This places it last inside the CPU
1544  * subtree.
1545  */
1546 static void
1547 perf_event_groups_insert(struct perf_event_groups *groups,
1548 			 struct perf_event *event)
1549 {
1550 	struct perf_event *node_event;
1551 	struct rb_node *parent;
1552 	struct rb_node **node;
1553 
1554 	event->group_index = ++groups->index;
1555 
1556 	node = &groups->tree.rb_node;
1557 	parent = *node;
1558 
1559 	while (*node) {
1560 		parent = *node;
1561 		node_event = container_of(*node, struct perf_event, group_node);
1562 
1563 		if (perf_event_groups_less(event, node_event))
1564 			node = &parent->rb_left;
1565 		else
1566 			node = &parent->rb_right;
1567 	}
1568 
1569 	rb_link_node(&event->group_node, parent, node);
1570 	rb_insert_color(&event->group_node, &groups->tree);
1571 }
1572 
1573 /*
1574  * Helper function to insert event into the pinned or flexible groups.
1575  */
1576 static void
1577 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1578 {
1579 	struct perf_event_groups *groups;
1580 
1581 	groups = get_event_groups(event, ctx);
1582 	perf_event_groups_insert(groups, event);
1583 }
1584 
1585 /*
1586  * Delete a group from a tree.
1587  */
1588 static void
1589 perf_event_groups_delete(struct perf_event_groups *groups,
1590 			 struct perf_event *event)
1591 {
1592 	WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1593 		     RB_EMPTY_ROOT(&groups->tree));
1594 
1595 	rb_erase(&event->group_node, &groups->tree);
1596 	init_event_group(event);
1597 }
1598 
1599 /*
1600  * Helper function to delete event from its groups.
1601  */
1602 static void
1603 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1604 {
1605 	struct perf_event_groups *groups;
1606 
1607 	groups = get_event_groups(event, ctx);
1608 	perf_event_groups_delete(groups, event);
1609 }
1610 
1611 /*
1612  * Get the leftmost event in the @cpu subtree.
1613  */
1614 static struct perf_event *
1615 perf_event_groups_first(struct perf_event_groups *groups, int cpu)
1616 {
1617 	struct perf_event *node_event = NULL, *match = NULL;
1618 	struct rb_node *node = groups->tree.rb_node;
1619 
1620 	while (node) {
1621 		node_event = container_of(node, struct perf_event, group_node);
1622 
1623 		if (cpu < node_event->cpu) {
1624 			node = node->rb_left;
1625 		} else if (cpu > node_event->cpu) {
1626 			node = node->rb_right;
1627 		} else {
1628 			match = node_event;
1629 			node = node->rb_left;
1630 		}
1631 	}
1632 
1633 	return match;
1634 }
1635 
1636 /*
1637  * Like rb_entry_next_safe() for the @cpu subtree.
1638  */
1639 static struct perf_event *
1640 perf_event_groups_next(struct perf_event *event)
1641 {
1642 	struct perf_event *next;
1643 
1644 	next = rb_entry_safe(rb_next(&event->group_node), typeof(*event), group_node);
1645 	if (next && next->cpu == event->cpu)
1646 		return next;
1647 
1648 	return NULL;
1649 }
1650 
1651 /*
1652  * Iterate through the whole groups tree.
1653  */
1654 #define perf_event_groups_for_each(event, groups)			\
1655 	for (event = rb_entry_safe(rb_first(&((groups)->tree)),		\
1656 				typeof(*event), group_node); event;	\
1657 		event = rb_entry_safe(rb_next(&event->group_node),	\
1658 				typeof(*event), group_node))
1659 
1660 /*
1661  * Add an event from the lists for its context.
1662  * Must be called with ctx->mutex and ctx->lock held.
1663  */
1664 static void
1665 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1666 {
1667 	lockdep_assert_held(&ctx->lock);
1668 
1669 	WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1670 	event->attach_state |= PERF_ATTACH_CONTEXT;
1671 
1672 	event->tstamp = perf_event_time(event);
1673 
1674 	/*
1675 	 * If we're a stand alone event or group leader, we go to the context
1676 	 * list, group events are kept attached to the group so that
1677 	 * perf_group_detach can, at all times, locate all siblings.
1678 	 */
1679 	if (event->group_leader == event) {
1680 		event->group_caps = event->event_caps;
1681 		add_event_to_groups(event, ctx);
1682 	}
1683 
1684 	list_update_cgroup_event(event, ctx, true);
1685 
1686 	list_add_rcu(&event->event_entry, &ctx->event_list);
1687 	ctx->nr_events++;
1688 	if (event->attr.inherit_stat)
1689 		ctx->nr_stat++;
1690 
1691 	ctx->generation++;
1692 }
1693 
1694 /*
1695  * Initialize event state based on the perf_event_attr::disabled.
1696  */
1697 static inline void perf_event__state_init(struct perf_event *event)
1698 {
1699 	event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1700 					      PERF_EVENT_STATE_INACTIVE;
1701 }
1702 
1703 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1704 {
1705 	int entry = sizeof(u64); /* value */
1706 	int size = 0;
1707 	int nr = 1;
1708 
1709 	if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1710 		size += sizeof(u64);
1711 
1712 	if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1713 		size += sizeof(u64);
1714 
1715 	if (event->attr.read_format & PERF_FORMAT_ID)
1716 		entry += sizeof(u64);
1717 
1718 	if (event->attr.read_format & PERF_FORMAT_GROUP) {
1719 		nr += nr_siblings;
1720 		size += sizeof(u64);
1721 	}
1722 
1723 	size += entry * nr;
1724 	event->read_size = size;
1725 }
1726 
1727 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1728 {
1729 	struct perf_sample_data *data;
1730 	u16 size = 0;
1731 
1732 	if (sample_type & PERF_SAMPLE_IP)
1733 		size += sizeof(data->ip);
1734 
1735 	if (sample_type & PERF_SAMPLE_ADDR)
1736 		size += sizeof(data->addr);
1737 
1738 	if (sample_type & PERF_SAMPLE_PERIOD)
1739 		size += sizeof(data->period);
1740 
1741 	if (sample_type & PERF_SAMPLE_WEIGHT)
1742 		size += sizeof(data->weight);
1743 
1744 	if (sample_type & PERF_SAMPLE_READ)
1745 		size += event->read_size;
1746 
1747 	if (sample_type & PERF_SAMPLE_DATA_SRC)
1748 		size += sizeof(data->data_src.val);
1749 
1750 	if (sample_type & PERF_SAMPLE_TRANSACTION)
1751 		size += sizeof(data->txn);
1752 
1753 	if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1754 		size += sizeof(data->phys_addr);
1755 
1756 	event->header_size = size;
1757 }
1758 
1759 /*
1760  * Called at perf_event creation and when events are attached/detached from a
1761  * group.
1762  */
1763 static void perf_event__header_size(struct perf_event *event)
1764 {
1765 	__perf_event_read_size(event,
1766 			       event->group_leader->nr_siblings);
1767 	__perf_event_header_size(event, event->attr.sample_type);
1768 }
1769 
1770 static void perf_event__id_header_size(struct perf_event *event)
1771 {
1772 	struct perf_sample_data *data;
1773 	u64 sample_type = event->attr.sample_type;
1774 	u16 size = 0;
1775 
1776 	if (sample_type & PERF_SAMPLE_TID)
1777 		size += sizeof(data->tid_entry);
1778 
1779 	if (sample_type & PERF_SAMPLE_TIME)
1780 		size += sizeof(data->time);
1781 
1782 	if (sample_type & PERF_SAMPLE_IDENTIFIER)
1783 		size += sizeof(data->id);
1784 
1785 	if (sample_type & PERF_SAMPLE_ID)
1786 		size += sizeof(data->id);
1787 
1788 	if (sample_type & PERF_SAMPLE_STREAM_ID)
1789 		size += sizeof(data->stream_id);
1790 
1791 	if (sample_type & PERF_SAMPLE_CPU)
1792 		size += sizeof(data->cpu_entry);
1793 
1794 	event->id_header_size = size;
1795 }
1796 
1797 static bool perf_event_validate_size(struct perf_event *event)
1798 {
1799 	/*
1800 	 * The values computed here will be over-written when we actually
1801 	 * attach the event.
1802 	 */
1803 	__perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1804 	__perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1805 	perf_event__id_header_size(event);
1806 
1807 	/*
1808 	 * Sum the lot; should not exceed the 64k limit we have on records.
1809 	 * Conservative limit to allow for callchains and other variable fields.
1810 	 */
1811 	if (event->read_size + event->header_size +
1812 	    event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1813 		return false;
1814 
1815 	return true;
1816 }
1817 
1818 static void perf_group_attach(struct perf_event *event)
1819 {
1820 	struct perf_event *group_leader = event->group_leader, *pos;
1821 
1822 	lockdep_assert_held(&event->ctx->lock);
1823 
1824 	/*
1825 	 * We can have double attach due to group movement in perf_event_open.
1826 	 */
1827 	if (event->attach_state & PERF_ATTACH_GROUP)
1828 		return;
1829 
1830 	event->attach_state |= PERF_ATTACH_GROUP;
1831 
1832 	if (group_leader == event)
1833 		return;
1834 
1835 	WARN_ON_ONCE(group_leader->ctx != event->ctx);
1836 
1837 	group_leader->group_caps &= event->event_caps;
1838 
1839 	list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1840 	group_leader->nr_siblings++;
1841 
1842 	perf_event__header_size(group_leader);
1843 
1844 	for_each_sibling_event(pos, group_leader)
1845 		perf_event__header_size(pos);
1846 }
1847 
1848 /*
1849  * Remove an event from the lists for its context.
1850  * Must be called with ctx->mutex and ctx->lock held.
1851  */
1852 static void
1853 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1854 {
1855 	WARN_ON_ONCE(event->ctx != ctx);
1856 	lockdep_assert_held(&ctx->lock);
1857 
1858 	/*
1859 	 * We can have double detach due to exit/hot-unplug + close.
1860 	 */
1861 	if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1862 		return;
1863 
1864 	event->attach_state &= ~PERF_ATTACH_CONTEXT;
1865 
1866 	list_update_cgroup_event(event, ctx, false);
1867 
1868 	ctx->nr_events--;
1869 	if (event->attr.inherit_stat)
1870 		ctx->nr_stat--;
1871 
1872 	list_del_rcu(&event->event_entry);
1873 
1874 	if (event->group_leader == event)
1875 		del_event_from_groups(event, ctx);
1876 
1877 	/*
1878 	 * If event was in error state, then keep it
1879 	 * that way, otherwise bogus counts will be
1880 	 * returned on read(). The only way to get out
1881 	 * of error state is by explicit re-enabling
1882 	 * of the event
1883 	 */
1884 	if (event->state > PERF_EVENT_STATE_OFF)
1885 		perf_event_set_state(event, PERF_EVENT_STATE_OFF);
1886 
1887 	ctx->generation++;
1888 }
1889 
1890 static void perf_group_detach(struct perf_event *event)
1891 {
1892 	struct perf_event *sibling, *tmp;
1893 	struct perf_event_context *ctx = event->ctx;
1894 
1895 	lockdep_assert_held(&ctx->lock);
1896 
1897 	/*
1898 	 * We can have double detach due to exit/hot-unplug + close.
1899 	 */
1900 	if (!(event->attach_state & PERF_ATTACH_GROUP))
1901 		return;
1902 
1903 	event->attach_state &= ~PERF_ATTACH_GROUP;
1904 
1905 	/*
1906 	 * If this is a sibling, remove it from its group.
1907 	 */
1908 	if (event->group_leader != event) {
1909 		list_del_init(&event->sibling_list);
1910 		event->group_leader->nr_siblings--;
1911 		goto out;
1912 	}
1913 
1914 	/*
1915 	 * If this was a group event with sibling events then
1916 	 * upgrade the siblings to singleton events by adding them
1917 	 * to whatever list we are on.
1918 	 */
1919 	list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
1920 
1921 		sibling->group_leader = sibling;
1922 		list_del_init(&sibling->sibling_list);
1923 
1924 		/* Inherit group flags from the previous leader */
1925 		sibling->group_caps = event->group_caps;
1926 
1927 		if (!RB_EMPTY_NODE(&event->group_node)) {
1928 			add_event_to_groups(sibling, event->ctx);
1929 
1930 			if (sibling->state == PERF_EVENT_STATE_ACTIVE) {
1931 				struct list_head *list = sibling->attr.pinned ?
1932 					&ctx->pinned_active : &ctx->flexible_active;
1933 
1934 				list_add_tail(&sibling->active_list, list);
1935 			}
1936 		}
1937 
1938 		WARN_ON_ONCE(sibling->ctx != event->ctx);
1939 	}
1940 
1941 out:
1942 	perf_event__header_size(event->group_leader);
1943 
1944 	for_each_sibling_event(tmp, event->group_leader)
1945 		perf_event__header_size(tmp);
1946 }
1947 
1948 static bool is_orphaned_event(struct perf_event *event)
1949 {
1950 	return event->state == PERF_EVENT_STATE_DEAD;
1951 }
1952 
1953 static inline int __pmu_filter_match(struct perf_event *event)
1954 {
1955 	struct pmu *pmu = event->pmu;
1956 	return pmu->filter_match ? pmu->filter_match(event) : 1;
1957 }
1958 
1959 /*
1960  * Check whether we should attempt to schedule an event group based on
1961  * PMU-specific filtering. An event group can consist of HW and SW events,
1962  * potentially with a SW leader, so we must check all the filters, to
1963  * determine whether a group is schedulable:
1964  */
1965 static inline int pmu_filter_match(struct perf_event *event)
1966 {
1967 	struct perf_event *sibling;
1968 
1969 	if (!__pmu_filter_match(event))
1970 		return 0;
1971 
1972 	for_each_sibling_event(sibling, event) {
1973 		if (!__pmu_filter_match(sibling))
1974 			return 0;
1975 	}
1976 
1977 	return 1;
1978 }
1979 
1980 static inline int
1981 event_filter_match(struct perf_event *event)
1982 {
1983 	return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1984 	       perf_cgroup_match(event) && pmu_filter_match(event);
1985 }
1986 
1987 static void
1988 event_sched_out(struct perf_event *event,
1989 		  struct perf_cpu_context *cpuctx,
1990 		  struct perf_event_context *ctx)
1991 {
1992 	enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
1993 
1994 	WARN_ON_ONCE(event->ctx != ctx);
1995 	lockdep_assert_held(&ctx->lock);
1996 
1997 	if (event->state != PERF_EVENT_STATE_ACTIVE)
1998 		return;
1999 
2000 	/*
2001 	 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2002 	 * we can schedule events _OUT_ individually through things like
2003 	 * __perf_remove_from_context().
2004 	 */
2005 	list_del_init(&event->active_list);
2006 
2007 	perf_pmu_disable(event->pmu);
2008 
2009 	event->pmu->del(event, 0);
2010 	event->oncpu = -1;
2011 
2012 	if (event->pending_disable) {
2013 		event->pending_disable = 0;
2014 		state = PERF_EVENT_STATE_OFF;
2015 	}
2016 	perf_event_set_state(event, state);
2017 
2018 	if (!is_software_event(event))
2019 		cpuctx->active_oncpu--;
2020 	if (!--ctx->nr_active)
2021 		perf_event_ctx_deactivate(ctx);
2022 	if (event->attr.freq && event->attr.sample_freq)
2023 		ctx->nr_freq--;
2024 	if (event->attr.exclusive || !cpuctx->active_oncpu)
2025 		cpuctx->exclusive = 0;
2026 
2027 	perf_pmu_enable(event->pmu);
2028 }
2029 
2030 static void
2031 group_sched_out(struct perf_event *group_event,
2032 		struct perf_cpu_context *cpuctx,
2033 		struct perf_event_context *ctx)
2034 {
2035 	struct perf_event *event;
2036 
2037 	if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2038 		return;
2039 
2040 	perf_pmu_disable(ctx->pmu);
2041 
2042 	event_sched_out(group_event, cpuctx, ctx);
2043 
2044 	/*
2045 	 * Schedule out siblings (if any):
2046 	 */
2047 	for_each_sibling_event(event, group_event)
2048 		event_sched_out(event, cpuctx, ctx);
2049 
2050 	perf_pmu_enable(ctx->pmu);
2051 
2052 	if (group_event->attr.exclusive)
2053 		cpuctx->exclusive = 0;
2054 }
2055 
2056 #define DETACH_GROUP	0x01UL
2057 
2058 /*
2059  * Cross CPU call to remove a performance event
2060  *
2061  * We disable the event on the hardware level first. After that we
2062  * remove it from the context list.
2063  */
2064 static void
2065 __perf_remove_from_context(struct perf_event *event,
2066 			   struct perf_cpu_context *cpuctx,
2067 			   struct perf_event_context *ctx,
2068 			   void *info)
2069 {
2070 	unsigned long flags = (unsigned long)info;
2071 
2072 	if (ctx->is_active & EVENT_TIME) {
2073 		update_context_time(ctx);
2074 		update_cgrp_time_from_cpuctx(cpuctx);
2075 	}
2076 
2077 	event_sched_out(event, cpuctx, ctx);
2078 	if (flags & DETACH_GROUP)
2079 		perf_group_detach(event);
2080 	list_del_event(event, ctx);
2081 
2082 	if (!ctx->nr_events && ctx->is_active) {
2083 		ctx->is_active = 0;
2084 		if (ctx->task) {
2085 			WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2086 			cpuctx->task_ctx = NULL;
2087 		}
2088 	}
2089 }
2090 
2091 /*
2092  * Remove the event from a task's (or a CPU's) list of events.
2093  *
2094  * If event->ctx is a cloned context, callers must make sure that
2095  * every task struct that event->ctx->task could possibly point to
2096  * remains valid.  This is OK when called from perf_release since
2097  * that only calls us on the top-level context, which can't be a clone.
2098  * When called from perf_event_exit_task, it's OK because the
2099  * context has been detached from its task.
2100  */
2101 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2102 {
2103 	struct perf_event_context *ctx = event->ctx;
2104 
2105 	lockdep_assert_held(&ctx->mutex);
2106 
2107 	event_function_call(event, __perf_remove_from_context, (void *)flags);
2108 
2109 	/*
2110 	 * The above event_function_call() can NO-OP when it hits
2111 	 * TASK_TOMBSTONE. In that case we must already have been detached
2112 	 * from the context (by perf_event_exit_event()) but the grouping
2113 	 * might still be in-tact.
2114 	 */
2115 	WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
2116 	if ((flags & DETACH_GROUP) &&
2117 	    (event->attach_state & PERF_ATTACH_GROUP)) {
2118 		/*
2119 		 * Since in that case we cannot possibly be scheduled, simply
2120 		 * detach now.
2121 		 */
2122 		raw_spin_lock_irq(&ctx->lock);
2123 		perf_group_detach(event);
2124 		raw_spin_unlock_irq(&ctx->lock);
2125 	}
2126 }
2127 
2128 /*
2129  * Cross CPU call to disable a performance event
2130  */
2131 static void __perf_event_disable(struct perf_event *event,
2132 				 struct perf_cpu_context *cpuctx,
2133 				 struct perf_event_context *ctx,
2134 				 void *info)
2135 {
2136 	if (event->state < PERF_EVENT_STATE_INACTIVE)
2137 		return;
2138 
2139 	if (ctx->is_active & EVENT_TIME) {
2140 		update_context_time(ctx);
2141 		update_cgrp_time_from_event(event);
2142 	}
2143 
2144 	if (event == event->group_leader)
2145 		group_sched_out(event, cpuctx, ctx);
2146 	else
2147 		event_sched_out(event, cpuctx, ctx);
2148 
2149 	perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2150 }
2151 
2152 /*
2153  * Disable an event.
2154  *
2155  * If event->ctx is a cloned context, callers must make sure that
2156  * every task struct that event->ctx->task could possibly point to
2157  * remains valid.  This condition is satisifed when called through
2158  * perf_event_for_each_child or perf_event_for_each because they
2159  * hold the top-level event's child_mutex, so any descendant that
2160  * goes to exit will block in perf_event_exit_event().
2161  *
2162  * When called from perf_pending_event it's OK because event->ctx
2163  * is the current context on this CPU and preemption is disabled,
2164  * hence we can't get into perf_event_task_sched_out for this context.
2165  */
2166 static void _perf_event_disable(struct perf_event *event)
2167 {
2168 	struct perf_event_context *ctx = event->ctx;
2169 
2170 	raw_spin_lock_irq(&ctx->lock);
2171 	if (event->state <= PERF_EVENT_STATE_OFF) {
2172 		raw_spin_unlock_irq(&ctx->lock);
2173 		return;
2174 	}
2175 	raw_spin_unlock_irq(&ctx->lock);
2176 
2177 	event_function_call(event, __perf_event_disable, NULL);
2178 }
2179 
2180 void perf_event_disable_local(struct perf_event *event)
2181 {
2182 	event_function_local(event, __perf_event_disable, NULL);
2183 }
2184 
2185 /*
2186  * Strictly speaking kernel users cannot create groups and therefore this
2187  * interface does not need the perf_event_ctx_lock() magic.
2188  */
2189 void perf_event_disable(struct perf_event *event)
2190 {
2191 	struct perf_event_context *ctx;
2192 
2193 	ctx = perf_event_ctx_lock(event);
2194 	_perf_event_disable(event);
2195 	perf_event_ctx_unlock(event, ctx);
2196 }
2197 EXPORT_SYMBOL_GPL(perf_event_disable);
2198 
2199 void perf_event_disable_inatomic(struct perf_event *event)
2200 {
2201 	event->pending_disable = 1;
2202 	irq_work_queue(&event->pending);
2203 }
2204 
2205 static void perf_set_shadow_time(struct perf_event *event,
2206 				 struct perf_event_context *ctx)
2207 {
2208 	/*
2209 	 * use the correct time source for the time snapshot
2210 	 *
2211 	 * We could get by without this by leveraging the
2212 	 * fact that to get to this function, the caller
2213 	 * has most likely already called update_context_time()
2214 	 * and update_cgrp_time_xx() and thus both timestamp
2215 	 * are identical (or very close). Given that tstamp is,
2216 	 * already adjusted for cgroup, we could say that:
2217 	 *    tstamp - ctx->timestamp
2218 	 * is equivalent to
2219 	 *    tstamp - cgrp->timestamp.
2220 	 *
2221 	 * Then, in perf_output_read(), the calculation would
2222 	 * work with no changes because:
2223 	 * - event is guaranteed scheduled in
2224 	 * - no scheduled out in between
2225 	 * - thus the timestamp would be the same
2226 	 *
2227 	 * But this is a bit hairy.
2228 	 *
2229 	 * So instead, we have an explicit cgroup call to remain
2230 	 * within the time time source all along. We believe it
2231 	 * is cleaner and simpler to understand.
2232 	 */
2233 	if (is_cgroup_event(event))
2234 		perf_cgroup_set_shadow_time(event, event->tstamp);
2235 	else
2236 		event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2237 }
2238 
2239 #define MAX_INTERRUPTS (~0ULL)
2240 
2241 static void perf_log_throttle(struct perf_event *event, int enable);
2242 static void perf_log_itrace_start(struct perf_event *event);
2243 
2244 static int
2245 event_sched_in(struct perf_event *event,
2246 		 struct perf_cpu_context *cpuctx,
2247 		 struct perf_event_context *ctx)
2248 {
2249 	int ret = 0;
2250 
2251 	lockdep_assert_held(&ctx->lock);
2252 
2253 	if (event->state <= PERF_EVENT_STATE_OFF)
2254 		return 0;
2255 
2256 	WRITE_ONCE(event->oncpu, smp_processor_id());
2257 	/*
2258 	 * Order event::oncpu write to happen before the ACTIVE state is
2259 	 * visible. This allows perf_event_{stop,read}() to observe the correct
2260 	 * ->oncpu if it sees ACTIVE.
2261 	 */
2262 	smp_wmb();
2263 	perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2264 
2265 	/*
2266 	 * Unthrottle events, since we scheduled we might have missed several
2267 	 * ticks already, also for a heavily scheduling task there is little
2268 	 * guarantee it'll get a tick in a timely manner.
2269 	 */
2270 	if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2271 		perf_log_throttle(event, 1);
2272 		event->hw.interrupts = 0;
2273 	}
2274 
2275 	perf_pmu_disable(event->pmu);
2276 
2277 	perf_set_shadow_time(event, ctx);
2278 
2279 	perf_log_itrace_start(event);
2280 
2281 	if (event->pmu->add(event, PERF_EF_START)) {
2282 		perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2283 		event->oncpu = -1;
2284 		ret = -EAGAIN;
2285 		goto out;
2286 	}
2287 
2288 	if (!is_software_event(event))
2289 		cpuctx->active_oncpu++;
2290 	if (!ctx->nr_active++)
2291 		perf_event_ctx_activate(ctx);
2292 	if (event->attr.freq && event->attr.sample_freq)
2293 		ctx->nr_freq++;
2294 
2295 	if (event->attr.exclusive)
2296 		cpuctx->exclusive = 1;
2297 
2298 out:
2299 	perf_pmu_enable(event->pmu);
2300 
2301 	return ret;
2302 }
2303 
2304 static int
2305 group_sched_in(struct perf_event *group_event,
2306 	       struct perf_cpu_context *cpuctx,
2307 	       struct perf_event_context *ctx)
2308 {
2309 	struct perf_event *event, *partial_group = NULL;
2310 	struct pmu *pmu = ctx->pmu;
2311 
2312 	if (group_event->state == PERF_EVENT_STATE_OFF)
2313 		return 0;
2314 
2315 	pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2316 
2317 	if (event_sched_in(group_event, cpuctx, ctx)) {
2318 		pmu->cancel_txn(pmu);
2319 		perf_mux_hrtimer_restart(cpuctx);
2320 		return -EAGAIN;
2321 	}
2322 
2323 	/*
2324 	 * Schedule in siblings as one group (if any):
2325 	 */
2326 	for_each_sibling_event(event, group_event) {
2327 		if (event_sched_in(event, cpuctx, ctx)) {
2328 			partial_group = event;
2329 			goto group_error;
2330 		}
2331 	}
2332 
2333 	if (!pmu->commit_txn(pmu))
2334 		return 0;
2335 
2336 group_error:
2337 	/*
2338 	 * Groups can be scheduled in as one unit only, so undo any
2339 	 * partial group before returning:
2340 	 * The events up to the failed event are scheduled out normally.
2341 	 */
2342 	for_each_sibling_event(event, group_event) {
2343 		if (event == partial_group)
2344 			break;
2345 
2346 		event_sched_out(event, cpuctx, ctx);
2347 	}
2348 	event_sched_out(group_event, cpuctx, ctx);
2349 
2350 	pmu->cancel_txn(pmu);
2351 
2352 	perf_mux_hrtimer_restart(cpuctx);
2353 
2354 	return -EAGAIN;
2355 }
2356 
2357 /*
2358  * Work out whether we can put this event group on the CPU now.
2359  */
2360 static int group_can_go_on(struct perf_event *event,
2361 			   struct perf_cpu_context *cpuctx,
2362 			   int can_add_hw)
2363 {
2364 	/*
2365 	 * Groups consisting entirely of software events can always go on.
2366 	 */
2367 	if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2368 		return 1;
2369 	/*
2370 	 * If an exclusive group is already on, no other hardware
2371 	 * events can go on.
2372 	 */
2373 	if (cpuctx->exclusive)
2374 		return 0;
2375 	/*
2376 	 * If this group is exclusive and there are already
2377 	 * events on the CPU, it can't go on.
2378 	 */
2379 	if (event->attr.exclusive && cpuctx->active_oncpu)
2380 		return 0;
2381 	/*
2382 	 * Otherwise, try to add it if all previous groups were able
2383 	 * to go on.
2384 	 */
2385 	return can_add_hw;
2386 }
2387 
2388 static void add_event_to_ctx(struct perf_event *event,
2389 			       struct perf_event_context *ctx)
2390 {
2391 	list_add_event(event, ctx);
2392 	perf_group_attach(event);
2393 }
2394 
2395 static void ctx_sched_out(struct perf_event_context *ctx,
2396 			  struct perf_cpu_context *cpuctx,
2397 			  enum event_type_t event_type);
2398 static void
2399 ctx_sched_in(struct perf_event_context *ctx,
2400 	     struct perf_cpu_context *cpuctx,
2401 	     enum event_type_t event_type,
2402 	     struct task_struct *task);
2403 
2404 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2405 			       struct perf_event_context *ctx,
2406 			       enum event_type_t event_type)
2407 {
2408 	if (!cpuctx->task_ctx)
2409 		return;
2410 
2411 	if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2412 		return;
2413 
2414 	ctx_sched_out(ctx, cpuctx, event_type);
2415 }
2416 
2417 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2418 				struct perf_event_context *ctx,
2419 				struct task_struct *task)
2420 {
2421 	cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2422 	if (ctx)
2423 		ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2424 	cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2425 	if (ctx)
2426 		ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2427 }
2428 
2429 /*
2430  * We want to maintain the following priority of scheduling:
2431  *  - CPU pinned (EVENT_CPU | EVENT_PINNED)
2432  *  - task pinned (EVENT_PINNED)
2433  *  - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2434  *  - task flexible (EVENT_FLEXIBLE).
2435  *
2436  * In order to avoid unscheduling and scheduling back in everything every
2437  * time an event is added, only do it for the groups of equal priority and
2438  * below.
2439  *
2440  * This can be called after a batch operation on task events, in which case
2441  * event_type is a bit mask of the types of events involved. For CPU events,
2442  * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2443  */
2444 static void ctx_resched(struct perf_cpu_context *cpuctx,
2445 			struct perf_event_context *task_ctx,
2446 			enum event_type_t event_type)
2447 {
2448 	enum event_type_t ctx_event_type;
2449 	bool cpu_event = !!(event_type & EVENT_CPU);
2450 
2451 	/*
2452 	 * If pinned groups are involved, flexible groups also need to be
2453 	 * scheduled out.
2454 	 */
2455 	if (event_type & EVENT_PINNED)
2456 		event_type |= EVENT_FLEXIBLE;
2457 
2458 	ctx_event_type = event_type & EVENT_ALL;
2459 
2460 	perf_pmu_disable(cpuctx->ctx.pmu);
2461 	if (task_ctx)
2462 		task_ctx_sched_out(cpuctx, task_ctx, event_type);
2463 
2464 	/*
2465 	 * Decide which cpu ctx groups to schedule out based on the types
2466 	 * of events that caused rescheduling:
2467 	 *  - EVENT_CPU: schedule out corresponding groups;
2468 	 *  - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2469 	 *  - otherwise, do nothing more.
2470 	 */
2471 	if (cpu_event)
2472 		cpu_ctx_sched_out(cpuctx, ctx_event_type);
2473 	else if (ctx_event_type & EVENT_PINNED)
2474 		cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2475 
2476 	perf_event_sched_in(cpuctx, task_ctx, current);
2477 	perf_pmu_enable(cpuctx->ctx.pmu);
2478 }
2479 
2480 /*
2481  * Cross CPU call to install and enable a performance event
2482  *
2483  * Very similar to remote_function() + event_function() but cannot assume that
2484  * things like ctx->is_active and cpuctx->task_ctx are set.
2485  */
2486 static int  __perf_install_in_context(void *info)
2487 {
2488 	struct perf_event *event = info;
2489 	struct perf_event_context *ctx = event->ctx;
2490 	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2491 	struct perf_event_context *task_ctx = cpuctx->task_ctx;
2492 	bool reprogram = true;
2493 	int ret = 0;
2494 
2495 	raw_spin_lock(&cpuctx->ctx.lock);
2496 	if (ctx->task) {
2497 		raw_spin_lock(&ctx->lock);
2498 		task_ctx = ctx;
2499 
2500 		reprogram = (ctx->task == current);
2501 
2502 		/*
2503 		 * If the task is running, it must be running on this CPU,
2504 		 * otherwise we cannot reprogram things.
2505 		 *
2506 		 * If its not running, we don't care, ctx->lock will
2507 		 * serialize against it becoming runnable.
2508 		 */
2509 		if (task_curr(ctx->task) && !reprogram) {
2510 			ret = -ESRCH;
2511 			goto unlock;
2512 		}
2513 
2514 		WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2515 	} else if (task_ctx) {
2516 		raw_spin_lock(&task_ctx->lock);
2517 	}
2518 
2519 #ifdef CONFIG_CGROUP_PERF
2520 	if (is_cgroup_event(event)) {
2521 		/*
2522 		 * If the current cgroup doesn't match the event's
2523 		 * cgroup, we should not try to schedule it.
2524 		 */
2525 		struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2526 		reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2527 					event->cgrp->css.cgroup);
2528 	}
2529 #endif
2530 
2531 	if (reprogram) {
2532 		ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2533 		add_event_to_ctx(event, ctx);
2534 		ctx_resched(cpuctx, task_ctx, get_event_type(event));
2535 	} else {
2536 		add_event_to_ctx(event, ctx);
2537 	}
2538 
2539 unlock:
2540 	perf_ctx_unlock(cpuctx, task_ctx);
2541 
2542 	return ret;
2543 }
2544 
2545 /*
2546  * Attach a performance event to a context.
2547  *
2548  * Very similar to event_function_call, see comment there.
2549  */
2550 static void
2551 perf_install_in_context(struct perf_event_context *ctx,
2552 			struct perf_event *event,
2553 			int cpu)
2554 {
2555 	struct task_struct *task = READ_ONCE(ctx->task);
2556 
2557 	lockdep_assert_held(&ctx->mutex);
2558 
2559 	if (event->cpu != -1)
2560 		event->cpu = cpu;
2561 
2562 	/*
2563 	 * Ensures that if we can observe event->ctx, both the event and ctx
2564 	 * will be 'complete'. See perf_iterate_sb_cpu().
2565 	 */
2566 	smp_store_release(&event->ctx, ctx);
2567 
2568 	if (!task) {
2569 		cpu_function_call(cpu, __perf_install_in_context, event);
2570 		return;
2571 	}
2572 
2573 	/*
2574 	 * Should not happen, we validate the ctx is still alive before calling.
2575 	 */
2576 	if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2577 		return;
2578 
2579 	/*
2580 	 * Installing events is tricky because we cannot rely on ctx->is_active
2581 	 * to be set in case this is the nr_events 0 -> 1 transition.
2582 	 *
2583 	 * Instead we use task_curr(), which tells us if the task is running.
2584 	 * However, since we use task_curr() outside of rq::lock, we can race
2585 	 * against the actual state. This means the result can be wrong.
2586 	 *
2587 	 * If we get a false positive, we retry, this is harmless.
2588 	 *
2589 	 * If we get a false negative, things are complicated. If we are after
2590 	 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2591 	 * value must be correct. If we're before, it doesn't matter since
2592 	 * perf_event_context_sched_in() will program the counter.
2593 	 *
2594 	 * However, this hinges on the remote context switch having observed
2595 	 * our task->perf_event_ctxp[] store, such that it will in fact take
2596 	 * ctx::lock in perf_event_context_sched_in().
2597 	 *
2598 	 * We do this by task_function_call(), if the IPI fails to hit the task
2599 	 * we know any future context switch of task must see the
2600 	 * perf_event_ctpx[] store.
2601 	 */
2602 
2603 	/*
2604 	 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2605 	 * task_cpu() load, such that if the IPI then does not find the task
2606 	 * running, a future context switch of that task must observe the
2607 	 * store.
2608 	 */
2609 	smp_mb();
2610 again:
2611 	if (!task_function_call(task, __perf_install_in_context, event))
2612 		return;
2613 
2614 	raw_spin_lock_irq(&ctx->lock);
2615 	task = ctx->task;
2616 	if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2617 		/*
2618 		 * Cannot happen because we already checked above (which also
2619 		 * cannot happen), and we hold ctx->mutex, which serializes us
2620 		 * against perf_event_exit_task_context().
2621 		 */
2622 		raw_spin_unlock_irq(&ctx->lock);
2623 		return;
2624 	}
2625 	/*
2626 	 * If the task is not running, ctx->lock will avoid it becoming so,
2627 	 * thus we can safely install the event.
2628 	 */
2629 	if (task_curr(task)) {
2630 		raw_spin_unlock_irq(&ctx->lock);
2631 		goto again;
2632 	}
2633 	add_event_to_ctx(event, ctx);
2634 	raw_spin_unlock_irq(&ctx->lock);
2635 }
2636 
2637 /*
2638  * Cross CPU call to enable a performance event
2639  */
2640 static void __perf_event_enable(struct perf_event *event,
2641 				struct perf_cpu_context *cpuctx,
2642 				struct perf_event_context *ctx,
2643 				void *info)
2644 {
2645 	struct perf_event *leader = event->group_leader;
2646 	struct perf_event_context *task_ctx;
2647 
2648 	if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2649 	    event->state <= PERF_EVENT_STATE_ERROR)
2650 		return;
2651 
2652 	if (ctx->is_active)
2653 		ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2654 
2655 	perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2656 
2657 	if (!ctx->is_active)
2658 		return;
2659 
2660 	if (!event_filter_match(event)) {
2661 		ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2662 		return;
2663 	}
2664 
2665 	/*
2666 	 * If the event is in a group and isn't the group leader,
2667 	 * then don't put it on unless the group is on.
2668 	 */
2669 	if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2670 		ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2671 		return;
2672 	}
2673 
2674 	task_ctx = cpuctx->task_ctx;
2675 	if (ctx->task)
2676 		WARN_ON_ONCE(task_ctx != ctx);
2677 
2678 	ctx_resched(cpuctx, task_ctx, get_event_type(event));
2679 }
2680 
2681 /*
2682  * Enable an event.
2683  *
2684  * If event->ctx is a cloned context, callers must make sure that
2685  * every task struct that event->ctx->task could possibly point to
2686  * remains valid.  This condition is satisfied when called through
2687  * perf_event_for_each_child or perf_event_for_each as described
2688  * for perf_event_disable.
2689  */
2690 static void _perf_event_enable(struct perf_event *event)
2691 {
2692 	struct perf_event_context *ctx = event->ctx;
2693 
2694 	raw_spin_lock_irq(&ctx->lock);
2695 	if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2696 	    event->state <  PERF_EVENT_STATE_ERROR) {
2697 		raw_spin_unlock_irq(&ctx->lock);
2698 		return;
2699 	}
2700 
2701 	/*
2702 	 * If the event is in error state, clear that first.
2703 	 *
2704 	 * That way, if we see the event in error state below, we know that it
2705 	 * has gone back into error state, as distinct from the task having
2706 	 * been scheduled away before the cross-call arrived.
2707 	 */
2708 	if (event->state == PERF_EVENT_STATE_ERROR)
2709 		event->state = PERF_EVENT_STATE_OFF;
2710 	raw_spin_unlock_irq(&ctx->lock);
2711 
2712 	event_function_call(event, __perf_event_enable, NULL);
2713 }
2714 
2715 /*
2716  * See perf_event_disable();
2717  */
2718 void perf_event_enable(struct perf_event *event)
2719 {
2720 	struct perf_event_context *ctx;
2721 
2722 	ctx = perf_event_ctx_lock(event);
2723 	_perf_event_enable(event);
2724 	perf_event_ctx_unlock(event, ctx);
2725 }
2726 EXPORT_SYMBOL_GPL(perf_event_enable);
2727 
2728 struct stop_event_data {
2729 	struct perf_event	*event;
2730 	unsigned int		restart;
2731 };
2732 
2733 static int __perf_event_stop(void *info)
2734 {
2735 	struct stop_event_data *sd = info;
2736 	struct perf_event *event = sd->event;
2737 
2738 	/* if it's already INACTIVE, do nothing */
2739 	if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2740 		return 0;
2741 
2742 	/* matches smp_wmb() in event_sched_in() */
2743 	smp_rmb();
2744 
2745 	/*
2746 	 * There is a window with interrupts enabled before we get here,
2747 	 * so we need to check again lest we try to stop another CPU's event.
2748 	 */
2749 	if (READ_ONCE(event->oncpu) != smp_processor_id())
2750 		return -EAGAIN;
2751 
2752 	event->pmu->stop(event, PERF_EF_UPDATE);
2753 
2754 	/*
2755 	 * May race with the actual stop (through perf_pmu_output_stop()),
2756 	 * but it is only used for events with AUX ring buffer, and such
2757 	 * events will refuse to restart because of rb::aux_mmap_count==0,
2758 	 * see comments in perf_aux_output_begin().
2759 	 *
2760 	 * Since this is happening on an event-local CPU, no trace is lost
2761 	 * while restarting.
2762 	 */
2763 	if (sd->restart)
2764 		event->pmu->start(event, 0);
2765 
2766 	return 0;
2767 }
2768 
2769 static int perf_event_stop(struct perf_event *event, int restart)
2770 {
2771 	struct stop_event_data sd = {
2772 		.event		= event,
2773 		.restart	= restart,
2774 	};
2775 	int ret = 0;
2776 
2777 	do {
2778 		if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2779 			return 0;
2780 
2781 		/* matches smp_wmb() in event_sched_in() */
2782 		smp_rmb();
2783 
2784 		/*
2785 		 * We only want to restart ACTIVE events, so if the event goes
2786 		 * inactive here (event->oncpu==-1), there's nothing more to do;
2787 		 * fall through with ret==-ENXIO.
2788 		 */
2789 		ret = cpu_function_call(READ_ONCE(event->oncpu),
2790 					__perf_event_stop, &sd);
2791 	} while (ret == -EAGAIN);
2792 
2793 	return ret;
2794 }
2795 
2796 /*
2797  * In order to contain the amount of racy and tricky in the address filter
2798  * configuration management, it is a two part process:
2799  *
2800  * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2801  *      we update the addresses of corresponding vmas in
2802  *	event::addr_filter_ranges array and bump the event::addr_filters_gen;
2803  * (p2) when an event is scheduled in (pmu::add), it calls
2804  *      perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2805  *      if the generation has changed since the previous call.
2806  *
2807  * If (p1) happens while the event is active, we restart it to force (p2).
2808  *
2809  * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2810  *     pre-existing mappings, called once when new filters arrive via SET_FILTER
2811  *     ioctl;
2812  * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2813  *     registered mapping, called for every new mmap(), with mm::mmap_sem down
2814  *     for reading;
2815  * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2816  *     of exec.
2817  */
2818 void perf_event_addr_filters_sync(struct perf_event *event)
2819 {
2820 	struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2821 
2822 	if (!has_addr_filter(event))
2823 		return;
2824 
2825 	raw_spin_lock(&ifh->lock);
2826 	if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2827 		event->pmu->addr_filters_sync(event);
2828 		event->hw.addr_filters_gen = event->addr_filters_gen;
2829 	}
2830 	raw_spin_unlock(&ifh->lock);
2831 }
2832 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2833 
2834 static int _perf_event_refresh(struct perf_event *event, int refresh)
2835 {
2836 	/*
2837 	 * not supported on inherited events
2838 	 */
2839 	if (event->attr.inherit || !is_sampling_event(event))
2840 		return -EINVAL;
2841 
2842 	atomic_add(refresh, &event->event_limit);
2843 	_perf_event_enable(event);
2844 
2845 	return 0;
2846 }
2847 
2848 /*
2849  * See perf_event_disable()
2850  */
2851 int perf_event_refresh(struct perf_event *event, int refresh)
2852 {
2853 	struct perf_event_context *ctx;
2854 	int ret;
2855 
2856 	ctx = perf_event_ctx_lock(event);
2857 	ret = _perf_event_refresh(event, refresh);
2858 	perf_event_ctx_unlock(event, ctx);
2859 
2860 	return ret;
2861 }
2862 EXPORT_SYMBOL_GPL(perf_event_refresh);
2863 
2864 static int perf_event_modify_breakpoint(struct perf_event *bp,
2865 					 struct perf_event_attr *attr)
2866 {
2867 	int err;
2868 
2869 	_perf_event_disable(bp);
2870 
2871 	err = modify_user_hw_breakpoint_check(bp, attr, true);
2872 
2873 	if (!bp->attr.disabled)
2874 		_perf_event_enable(bp);
2875 
2876 	return err;
2877 }
2878 
2879 static int perf_event_modify_attr(struct perf_event *event,
2880 				  struct perf_event_attr *attr)
2881 {
2882 	if (event->attr.type != attr->type)
2883 		return -EINVAL;
2884 
2885 	switch (event->attr.type) {
2886 	case PERF_TYPE_BREAKPOINT:
2887 		return perf_event_modify_breakpoint(event, attr);
2888 	default:
2889 		/* Place holder for future additions. */
2890 		return -EOPNOTSUPP;
2891 	}
2892 }
2893 
2894 static void ctx_sched_out(struct perf_event_context *ctx,
2895 			  struct perf_cpu_context *cpuctx,
2896 			  enum event_type_t event_type)
2897 {
2898 	struct perf_event *event, *tmp;
2899 	int is_active = ctx->is_active;
2900 
2901 	lockdep_assert_held(&ctx->lock);
2902 
2903 	if (likely(!ctx->nr_events)) {
2904 		/*
2905 		 * See __perf_remove_from_context().
2906 		 */
2907 		WARN_ON_ONCE(ctx->is_active);
2908 		if (ctx->task)
2909 			WARN_ON_ONCE(cpuctx->task_ctx);
2910 		return;
2911 	}
2912 
2913 	ctx->is_active &= ~event_type;
2914 	if (!(ctx->is_active & EVENT_ALL))
2915 		ctx->is_active = 0;
2916 
2917 	if (ctx->task) {
2918 		WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2919 		if (!ctx->is_active)
2920 			cpuctx->task_ctx = NULL;
2921 	}
2922 
2923 	/*
2924 	 * Always update time if it was set; not only when it changes.
2925 	 * Otherwise we can 'forget' to update time for any but the last
2926 	 * context we sched out. For example:
2927 	 *
2928 	 *   ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2929 	 *   ctx_sched_out(.event_type = EVENT_PINNED)
2930 	 *
2931 	 * would only update time for the pinned events.
2932 	 */
2933 	if (is_active & EVENT_TIME) {
2934 		/* update (and stop) ctx time */
2935 		update_context_time(ctx);
2936 		update_cgrp_time_from_cpuctx(cpuctx);
2937 	}
2938 
2939 	is_active ^= ctx->is_active; /* changed bits */
2940 
2941 	if (!ctx->nr_active || !(is_active & EVENT_ALL))
2942 		return;
2943 
2944 	perf_pmu_disable(ctx->pmu);
2945 	if (is_active & EVENT_PINNED) {
2946 		list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
2947 			group_sched_out(event, cpuctx, ctx);
2948 	}
2949 
2950 	if (is_active & EVENT_FLEXIBLE) {
2951 		list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
2952 			group_sched_out(event, cpuctx, ctx);
2953 	}
2954 	perf_pmu_enable(ctx->pmu);
2955 }
2956 
2957 /*
2958  * Test whether two contexts are equivalent, i.e. whether they have both been
2959  * cloned from the same version of the same context.
2960  *
2961  * Equivalence is measured using a generation number in the context that is
2962  * incremented on each modification to it; see unclone_ctx(), list_add_event()
2963  * and list_del_event().
2964  */
2965 static int context_equiv(struct perf_event_context *ctx1,
2966 			 struct perf_event_context *ctx2)
2967 {
2968 	lockdep_assert_held(&ctx1->lock);
2969 	lockdep_assert_held(&ctx2->lock);
2970 
2971 	/* Pinning disables the swap optimization */
2972 	if (ctx1->pin_count || ctx2->pin_count)
2973 		return 0;
2974 
2975 	/* If ctx1 is the parent of ctx2 */
2976 	if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2977 		return 1;
2978 
2979 	/* If ctx2 is the parent of ctx1 */
2980 	if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2981 		return 1;
2982 
2983 	/*
2984 	 * If ctx1 and ctx2 have the same parent; we flatten the parent
2985 	 * hierarchy, see perf_event_init_context().
2986 	 */
2987 	if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2988 			ctx1->parent_gen == ctx2->parent_gen)
2989 		return 1;
2990 
2991 	/* Unmatched */
2992 	return 0;
2993 }
2994 
2995 static void __perf_event_sync_stat(struct perf_event *event,
2996 				     struct perf_event *next_event)
2997 {
2998 	u64 value;
2999 
3000 	if (!event->attr.inherit_stat)
3001 		return;
3002 
3003 	/*
3004 	 * Update the event value, we cannot use perf_event_read()
3005 	 * because we're in the middle of a context switch and have IRQs
3006 	 * disabled, which upsets smp_call_function_single(), however
3007 	 * we know the event must be on the current CPU, therefore we
3008 	 * don't need to use it.
3009 	 */
3010 	if (event->state == PERF_EVENT_STATE_ACTIVE)
3011 		event->pmu->read(event);
3012 
3013 	perf_event_update_time(event);
3014 
3015 	/*
3016 	 * In order to keep per-task stats reliable we need to flip the event
3017 	 * values when we flip the contexts.
3018 	 */
3019 	value = local64_read(&next_event->count);
3020 	value = local64_xchg(&event->count, value);
3021 	local64_set(&next_event->count, value);
3022 
3023 	swap(event->total_time_enabled, next_event->total_time_enabled);
3024 	swap(event->total_time_running, next_event->total_time_running);
3025 
3026 	/*
3027 	 * Since we swizzled the values, update the user visible data too.
3028 	 */
3029 	perf_event_update_userpage(event);
3030 	perf_event_update_userpage(next_event);
3031 }
3032 
3033 static void perf_event_sync_stat(struct perf_event_context *ctx,
3034 				   struct perf_event_context *next_ctx)
3035 {
3036 	struct perf_event *event, *next_event;
3037 
3038 	if (!ctx->nr_stat)
3039 		return;
3040 
3041 	update_context_time(ctx);
3042 
3043 	event = list_first_entry(&ctx->event_list,
3044 				   struct perf_event, event_entry);
3045 
3046 	next_event = list_first_entry(&next_ctx->event_list,
3047 					struct perf_event, event_entry);
3048 
3049 	while (&event->event_entry != &ctx->event_list &&
3050 	       &next_event->event_entry != &next_ctx->event_list) {
3051 
3052 		__perf_event_sync_stat(event, next_event);
3053 
3054 		event = list_next_entry(event, event_entry);
3055 		next_event = list_next_entry(next_event, event_entry);
3056 	}
3057 }
3058 
3059 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3060 					 struct task_struct *next)
3061 {
3062 	struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3063 	struct perf_event_context *next_ctx;
3064 	struct perf_event_context *parent, *next_parent;
3065 	struct perf_cpu_context *cpuctx;
3066 	int do_switch = 1;
3067 
3068 	if (likely(!ctx))
3069 		return;
3070 
3071 	cpuctx = __get_cpu_context(ctx);
3072 	if (!cpuctx->task_ctx)
3073 		return;
3074 
3075 	rcu_read_lock();
3076 	next_ctx = next->perf_event_ctxp[ctxn];
3077 	if (!next_ctx)
3078 		goto unlock;
3079 
3080 	parent = rcu_dereference(ctx->parent_ctx);
3081 	next_parent = rcu_dereference(next_ctx->parent_ctx);
3082 
3083 	/* If neither context have a parent context; they cannot be clones. */
3084 	if (!parent && !next_parent)
3085 		goto unlock;
3086 
3087 	if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3088 		/*
3089 		 * Looks like the two contexts are clones, so we might be
3090 		 * able to optimize the context switch.  We lock both
3091 		 * contexts and check that they are clones under the
3092 		 * lock (including re-checking that neither has been
3093 		 * uncloned in the meantime).  It doesn't matter which
3094 		 * order we take the locks because no other cpu could
3095 		 * be trying to lock both of these tasks.
3096 		 */
3097 		raw_spin_lock(&ctx->lock);
3098 		raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3099 		if (context_equiv(ctx, next_ctx)) {
3100 			WRITE_ONCE(ctx->task, next);
3101 			WRITE_ONCE(next_ctx->task, task);
3102 
3103 			swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3104 
3105 			/*
3106 			 * RCU_INIT_POINTER here is safe because we've not
3107 			 * modified the ctx and the above modification of
3108 			 * ctx->task and ctx->task_ctx_data are immaterial
3109 			 * since those values are always verified under
3110 			 * ctx->lock which we're now holding.
3111 			 */
3112 			RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3113 			RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3114 
3115 			do_switch = 0;
3116 
3117 			perf_event_sync_stat(ctx, next_ctx);
3118 		}
3119 		raw_spin_unlock(&next_ctx->lock);
3120 		raw_spin_unlock(&ctx->lock);
3121 	}
3122 unlock:
3123 	rcu_read_unlock();
3124 
3125 	if (do_switch) {
3126 		raw_spin_lock(&ctx->lock);
3127 		task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3128 		raw_spin_unlock(&ctx->lock);
3129 	}
3130 }
3131 
3132 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3133 
3134 void perf_sched_cb_dec(struct pmu *pmu)
3135 {
3136 	struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3137 
3138 	this_cpu_dec(perf_sched_cb_usages);
3139 
3140 	if (!--cpuctx->sched_cb_usage)
3141 		list_del(&cpuctx->sched_cb_entry);
3142 }
3143 
3144 
3145 void perf_sched_cb_inc(struct pmu *pmu)
3146 {
3147 	struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3148 
3149 	if (!cpuctx->sched_cb_usage++)
3150 		list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3151 
3152 	this_cpu_inc(perf_sched_cb_usages);
3153 }
3154 
3155 /*
3156  * This function provides the context switch callback to the lower code
3157  * layer. It is invoked ONLY when the context switch callback is enabled.
3158  *
3159  * This callback is relevant even to per-cpu events; for example multi event
3160  * PEBS requires this to provide PID/TID information. This requires we flush
3161  * all queued PEBS records before we context switch to a new task.
3162  */
3163 static void perf_pmu_sched_task(struct task_struct *prev,
3164 				struct task_struct *next,
3165 				bool sched_in)
3166 {
3167 	struct perf_cpu_context *cpuctx;
3168 	struct pmu *pmu;
3169 
3170 	if (prev == next)
3171 		return;
3172 
3173 	list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3174 		pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3175 
3176 		if (WARN_ON_ONCE(!pmu->sched_task))
3177 			continue;
3178 
3179 		perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3180 		perf_pmu_disable(pmu);
3181 
3182 		pmu->sched_task(cpuctx->task_ctx, sched_in);
3183 
3184 		perf_pmu_enable(pmu);
3185 		perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3186 	}
3187 }
3188 
3189 static void perf_event_switch(struct task_struct *task,
3190 			      struct task_struct *next_prev, bool sched_in);
3191 
3192 #define for_each_task_context_nr(ctxn)					\
3193 	for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3194 
3195 /*
3196  * Called from scheduler to remove the events of the current task,
3197  * with interrupts disabled.
3198  *
3199  * We stop each event and update the event value in event->count.
3200  *
3201  * This does not protect us against NMI, but disable()
3202  * sets the disabled bit in the control field of event _before_
3203  * accessing the event control register. If a NMI hits, then it will
3204  * not restart the event.
3205  */
3206 void __perf_event_task_sched_out(struct task_struct *task,
3207 				 struct task_struct *next)
3208 {
3209 	int ctxn;
3210 
3211 	if (__this_cpu_read(perf_sched_cb_usages))
3212 		perf_pmu_sched_task(task, next, false);
3213 
3214 	if (atomic_read(&nr_switch_events))
3215 		perf_event_switch(task, next, false);
3216 
3217 	for_each_task_context_nr(ctxn)
3218 		perf_event_context_sched_out(task, ctxn, next);
3219 
3220 	/*
3221 	 * if cgroup events exist on this CPU, then we need
3222 	 * to check if we have to switch out PMU state.
3223 	 * cgroup event are system-wide mode only
3224 	 */
3225 	if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3226 		perf_cgroup_sched_out(task, next);
3227 }
3228 
3229 /*
3230  * Called with IRQs disabled
3231  */
3232 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3233 			      enum event_type_t event_type)
3234 {
3235 	ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3236 }
3237 
3238 static int visit_groups_merge(struct perf_event_groups *groups, int cpu,
3239 			      int (*func)(struct perf_event *, void *), void *data)
3240 {
3241 	struct perf_event **evt, *evt1, *evt2;
3242 	int ret;
3243 
3244 	evt1 = perf_event_groups_first(groups, -1);
3245 	evt2 = perf_event_groups_first(groups, cpu);
3246 
3247 	while (evt1 || evt2) {
3248 		if (evt1 && evt2) {
3249 			if (evt1->group_index < evt2->group_index)
3250 				evt = &evt1;
3251 			else
3252 				evt = &evt2;
3253 		} else if (evt1) {
3254 			evt = &evt1;
3255 		} else {
3256 			evt = &evt2;
3257 		}
3258 
3259 		ret = func(*evt, data);
3260 		if (ret)
3261 			return ret;
3262 
3263 		*evt = perf_event_groups_next(*evt);
3264 	}
3265 
3266 	return 0;
3267 }
3268 
3269 struct sched_in_data {
3270 	struct perf_event_context *ctx;
3271 	struct perf_cpu_context *cpuctx;
3272 	int can_add_hw;
3273 };
3274 
3275 static int pinned_sched_in(struct perf_event *event, void *data)
3276 {
3277 	struct sched_in_data *sid = data;
3278 
3279 	if (event->state <= PERF_EVENT_STATE_OFF)
3280 		return 0;
3281 
3282 	if (!event_filter_match(event))
3283 		return 0;
3284 
3285 	if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3286 		if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3287 			list_add_tail(&event->active_list, &sid->ctx->pinned_active);
3288 	}
3289 
3290 	/*
3291 	 * If this pinned group hasn't been scheduled,
3292 	 * put it in error state.
3293 	 */
3294 	if (event->state == PERF_EVENT_STATE_INACTIVE)
3295 		perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3296 
3297 	return 0;
3298 }
3299 
3300 static int flexible_sched_in(struct perf_event *event, void *data)
3301 {
3302 	struct sched_in_data *sid = data;
3303 
3304 	if (event->state <= PERF_EVENT_STATE_OFF)
3305 		return 0;
3306 
3307 	if (!event_filter_match(event))
3308 		return 0;
3309 
3310 	if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3311 		if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3312 			list_add_tail(&event->active_list, &sid->ctx->flexible_active);
3313 		else
3314 			sid->can_add_hw = 0;
3315 	}
3316 
3317 	return 0;
3318 }
3319 
3320 static void
3321 ctx_pinned_sched_in(struct perf_event_context *ctx,
3322 		    struct perf_cpu_context *cpuctx)
3323 {
3324 	struct sched_in_data sid = {
3325 		.ctx = ctx,
3326 		.cpuctx = cpuctx,
3327 		.can_add_hw = 1,
3328 	};
3329 
3330 	visit_groups_merge(&ctx->pinned_groups,
3331 			   smp_processor_id(),
3332 			   pinned_sched_in, &sid);
3333 }
3334 
3335 static void
3336 ctx_flexible_sched_in(struct perf_event_context *ctx,
3337 		      struct perf_cpu_context *cpuctx)
3338 {
3339 	struct sched_in_data sid = {
3340 		.ctx = ctx,
3341 		.cpuctx = cpuctx,
3342 		.can_add_hw = 1,
3343 	};
3344 
3345 	visit_groups_merge(&ctx->flexible_groups,
3346 			   smp_processor_id(),
3347 			   flexible_sched_in, &sid);
3348 }
3349 
3350 static void
3351 ctx_sched_in(struct perf_event_context *ctx,
3352 	     struct perf_cpu_context *cpuctx,
3353 	     enum event_type_t event_type,
3354 	     struct task_struct *task)
3355 {
3356 	int is_active = ctx->is_active;
3357 	u64 now;
3358 
3359 	lockdep_assert_held(&ctx->lock);
3360 
3361 	if (likely(!ctx->nr_events))
3362 		return;
3363 
3364 	ctx->is_active |= (event_type | EVENT_TIME);
3365 	if (ctx->task) {
3366 		if (!is_active)
3367 			cpuctx->task_ctx = ctx;
3368 		else
3369 			WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3370 	}
3371 
3372 	is_active ^= ctx->is_active; /* changed bits */
3373 
3374 	if (is_active & EVENT_TIME) {
3375 		/* start ctx time */
3376 		now = perf_clock();
3377 		ctx->timestamp = now;
3378 		perf_cgroup_set_timestamp(task, ctx);
3379 	}
3380 
3381 	/*
3382 	 * First go through the list and put on any pinned groups
3383 	 * in order to give them the best chance of going on.
3384 	 */
3385 	if (is_active & EVENT_PINNED)
3386 		ctx_pinned_sched_in(ctx, cpuctx);
3387 
3388 	/* Then walk through the lower prio flexible groups */
3389 	if (is_active & EVENT_FLEXIBLE)
3390 		ctx_flexible_sched_in(ctx, cpuctx);
3391 }
3392 
3393 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3394 			     enum event_type_t event_type,
3395 			     struct task_struct *task)
3396 {
3397 	struct perf_event_context *ctx = &cpuctx->ctx;
3398 
3399 	ctx_sched_in(ctx, cpuctx, event_type, task);
3400 }
3401 
3402 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3403 					struct task_struct *task)
3404 {
3405 	struct perf_cpu_context *cpuctx;
3406 
3407 	cpuctx = __get_cpu_context(ctx);
3408 	if (cpuctx->task_ctx == ctx)
3409 		return;
3410 
3411 	perf_ctx_lock(cpuctx, ctx);
3412 	/*
3413 	 * We must check ctx->nr_events while holding ctx->lock, such
3414 	 * that we serialize against perf_install_in_context().
3415 	 */
3416 	if (!ctx->nr_events)
3417 		goto unlock;
3418 
3419 	perf_pmu_disable(ctx->pmu);
3420 	/*
3421 	 * We want to keep the following priority order:
3422 	 * cpu pinned (that don't need to move), task pinned,
3423 	 * cpu flexible, task flexible.
3424 	 *
3425 	 * However, if task's ctx is not carrying any pinned
3426 	 * events, no need to flip the cpuctx's events around.
3427 	 */
3428 	if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3429 		cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3430 	perf_event_sched_in(cpuctx, ctx, task);
3431 	perf_pmu_enable(ctx->pmu);
3432 
3433 unlock:
3434 	perf_ctx_unlock(cpuctx, ctx);
3435 }
3436 
3437 /*
3438  * Called from scheduler to add the events of the current task
3439  * with interrupts disabled.
3440  *
3441  * We restore the event value and then enable it.
3442  *
3443  * This does not protect us against NMI, but enable()
3444  * sets the enabled bit in the control field of event _before_
3445  * accessing the event control register. If a NMI hits, then it will
3446  * keep the event running.
3447  */
3448 void __perf_event_task_sched_in(struct task_struct *prev,
3449 				struct task_struct *task)
3450 {
3451 	struct perf_event_context *ctx;
3452 	int ctxn;
3453 
3454 	/*
3455 	 * If cgroup events exist on this CPU, then we need to check if we have
3456 	 * to switch in PMU state; cgroup event are system-wide mode only.
3457 	 *
3458 	 * Since cgroup events are CPU events, we must schedule these in before
3459 	 * we schedule in the task events.
3460 	 */
3461 	if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3462 		perf_cgroup_sched_in(prev, task);
3463 
3464 	for_each_task_context_nr(ctxn) {
3465 		ctx = task->perf_event_ctxp[ctxn];
3466 		if (likely(!ctx))
3467 			continue;
3468 
3469 		perf_event_context_sched_in(ctx, task);
3470 	}
3471 
3472 	if (atomic_read(&nr_switch_events))
3473 		perf_event_switch(task, prev, true);
3474 
3475 	if (__this_cpu_read(perf_sched_cb_usages))
3476 		perf_pmu_sched_task(prev, task, true);
3477 }
3478 
3479 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3480 {
3481 	u64 frequency = event->attr.sample_freq;
3482 	u64 sec = NSEC_PER_SEC;
3483 	u64 divisor, dividend;
3484 
3485 	int count_fls, nsec_fls, frequency_fls, sec_fls;
3486 
3487 	count_fls = fls64(count);
3488 	nsec_fls = fls64(nsec);
3489 	frequency_fls = fls64(frequency);
3490 	sec_fls = 30;
3491 
3492 	/*
3493 	 * We got @count in @nsec, with a target of sample_freq HZ
3494 	 * the target period becomes:
3495 	 *
3496 	 *             @count * 10^9
3497 	 * period = -------------------
3498 	 *          @nsec * sample_freq
3499 	 *
3500 	 */
3501 
3502 	/*
3503 	 * Reduce accuracy by one bit such that @a and @b converge
3504 	 * to a similar magnitude.
3505 	 */
3506 #define REDUCE_FLS(a, b)		\
3507 do {					\
3508 	if (a##_fls > b##_fls) {	\
3509 		a >>= 1;		\
3510 		a##_fls--;		\
3511 	} else {			\
3512 		b >>= 1;		\
3513 		b##_fls--;		\
3514 	}				\
3515 } while (0)
3516 
3517 	/*
3518 	 * Reduce accuracy until either term fits in a u64, then proceed with
3519 	 * the other, so that finally we can do a u64/u64 division.
3520 	 */
3521 	while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3522 		REDUCE_FLS(nsec, frequency);
3523 		REDUCE_FLS(sec, count);
3524 	}
3525 
3526 	if (count_fls + sec_fls > 64) {
3527 		divisor = nsec * frequency;
3528 
3529 		while (count_fls + sec_fls > 64) {
3530 			REDUCE_FLS(count, sec);
3531 			divisor >>= 1;
3532 		}
3533 
3534 		dividend = count * sec;
3535 	} else {
3536 		dividend = count * sec;
3537 
3538 		while (nsec_fls + frequency_fls > 64) {
3539 			REDUCE_FLS(nsec, frequency);
3540 			dividend >>= 1;
3541 		}
3542 
3543 		divisor = nsec * frequency;
3544 	}
3545 
3546 	if (!divisor)
3547 		return dividend;
3548 
3549 	return div64_u64(dividend, divisor);
3550 }
3551 
3552 static DEFINE_PER_CPU(int, perf_throttled_count);
3553 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3554 
3555 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3556 {
3557 	struct hw_perf_event *hwc = &event->hw;
3558 	s64 period, sample_period;
3559 	s64 delta;
3560 
3561 	period = perf_calculate_period(event, nsec, count);
3562 
3563 	delta = (s64)(period - hwc->sample_period);
3564 	delta = (delta + 7) / 8; /* low pass filter */
3565 
3566 	sample_period = hwc->sample_period + delta;
3567 
3568 	if (!sample_period)
3569 		sample_period = 1;
3570 
3571 	hwc->sample_period = sample_period;
3572 
3573 	if (local64_read(&hwc->period_left) > 8*sample_period) {
3574 		if (disable)
3575 			event->pmu->stop(event, PERF_EF_UPDATE);
3576 
3577 		local64_set(&hwc->period_left, 0);
3578 
3579 		if (disable)
3580 			event->pmu->start(event, PERF_EF_RELOAD);
3581 	}
3582 }
3583 
3584 /*
3585  * combine freq adjustment with unthrottling to avoid two passes over the
3586  * events. At the same time, make sure, having freq events does not change
3587  * the rate of unthrottling as that would introduce bias.
3588  */
3589 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3590 					   int needs_unthr)
3591 {
3592 	struct perf_event *event;
3593 	struct hw_perf_event *hwc;
3594 	u64 now, period = TICK_NSEC;
3595 	s64 delta;
3596 
3597 	/*
3598 	 * only need to iterate over all events iff:
3599 	 * - context have events in frequency mode (needs freq adjust)
3600 	 * - there are events to unthrottle on this cpu
3601 	 */
3602 	if (!(ctx->nr_freq || needs_unthr))
3603 		return;
3604 
3605 	raw_spin_lock(&ctx->lock);
3606 	perf_pmu_disable(ctx->pmu);
3607 
3608 	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3609 		if (event->state != PERF_EVENT_STATE_ACTIVE)
3610 			continue;
3611 
3612 		if (!event_filter_match(event))
3613 			continue;
3614 
3615 		perf_pmu_disable(event->pmu);
3616 
3617 		hwc = &event->hw;
3618 
3619 		if (hwc->interrupts == MAX_INTERRUPTS) {
3620 			hwc->interrupts = 0;
3621 			perf_log_throttle(event, 1);
3622 			event->pmu->start(event, 0);
3623 		}
3624 
3625 		if (!event->attr.freq || !event->attr.sample_freq)
3626 			goto next;
3627 
3628 		/*
3629 		 * stop the event and update event->count
3630 		 */
3631 		event->pmu->stop(event, PERF_EF_UPDATE);
3632 
3633 		now = local64_read(&event->count);
3634 		delta = now - hwc->freq_count_stamp;
3635 		hwc->freq_count_stamp = now;
3636 
3637 		/*
3638 		 * restart the event
3639 		 * reload only if value has changed
3640 		 * we have stopped the event so tell that
3641 		 * to perf_adjust_period() to avoid stopping it
3642 		 * twice.
3643 		 */
3644 		if (delta > 0)
3645 			perf_adjust_period(event, period, delta, false);
3646 
3647 		event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3648 	next:
3649 		perf_pmu_enable(event->pmu);
3650 	}
3651 
3652 	perf_pmu_enable(ctx->pmu);
3653 	raw_spin_unlock(&ctx->lock);
3654 }
3655 
3656 /*
3657  * Move @event to the tail of the @ctx's elegible events.
3658  */
3659 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
3660 {
3661 	/*
3662 	 * Rotate the first entry last of non-pinned groups. Rotation might be
3663 	 * disabled by the inheritance code.
3664 	 */
3665 	if (ctx->rotate_disable)
3666 		return;
3667 
3668 	perf_event_groups_delete(&ctx->flexible_groups, event);
3669 	perf_event_groups_insert(&ctx->flexible_groups, event);
3670 }
3671 
3672 static inline struct perf_event *
3673 ctx_first_active(struct perf_event_context *ctx)
3674 {
3675 	return list_first_entry_or_null(&ctx->flexible_active,
3676 					struct perf_event, active_list);
3677 }
3678 
3679 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
3680 {
3681 	struct perf_event *cpu_event = NULL, *task_event = NULL;
3682 	bool cpu_rotate = false, task_rotate = false;
3683 	struct perf_event_context *ctx = NULL;
3684 
3685 	/*
3686 	 * Since we run this from IRQ context, nobody can install new
3687 	 * events, thus the event count values are stable.
3688 	 */
3689 
3690 	if (cpuctx->ctx.nr_events) {
3691 		if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3692 			cpu_rotate = true;
3693 	}
3694 
3695 	ctx = cpuctx->task_ctx;
3696 	if (ctx && ctx->nr_events) {
3697 		if (ctx->nr_events != ctx->nr_active)
3698 			task_rotate = true;
3699 	}
3700 
3701 	if (!(cpu_rotate || task_rotate))
3702 		return false;
3703 
3704 	perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3705 	perf_pmu_disable(cpuctx->ctx.pmu);
3706 
3707 	if (task_rotate)
3708 		task_event = ctx_first_active(ctx);
3709 	if (cpu_rotate)
3710 		cpu_event = ctx_first_active(&cpuctx->ctx);
3711 
3712 	/*
3713 	 * As per the order given at ctx_resched() first 'pop' task flexible
3714 	 * and then, if needed CPU flexible.
3715 	 */
3716 	if (task_event || (ctx && cpu_event))
3717 		ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3718 	if (cpu_event)
3719 		cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3720 
3721 	if (task_event)
3722 		rotate_ctx(ctx, task_event);
3723 	if (cpu_event)
3724 		rotate_ctx(&cpuctx->ctx, cpu_event);
3725 
3726 	perf_event_sched_in(cpuctx, ctx, current);
3727 
3728 	perf_pmu_enable(cpuctx->ctx.pmu);
3729 	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3730 
3731 	return true;
3732 }
3733 
3734 void perf_event_task_tick(void)
3735 {
3736 	struct list_head *head = this_cpu_ptr(&active_ctx_list);
3737 	struct perf_event_context *ctx, *tmp;
3738 	int throttled;
3739 
3740 	lockdep_assert_irqs_disabled();
3741 
3742 	__this_cpu_inc(perf_throttled_seq);
3743 	throttled = __this_cpu_xchg(perf_throttled_count, 0);
3744 	tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3745 
3746 	list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3747 		perf_adjust_freq_unthr_context(ctx, throttled);
3748 }
3749 
3750 static int event_enable_on_exec(struct perf_event *event,
3751 				struct perf_event_context *ctx)
3752 {
3753 	if (!event->attr.enable_on_exec)
3754 		return 0;
3755 
3756 	event->attr.enable_on_exec = 0;
3757 	if (event->state >= PERF_EVENT_STATE_INACTIVE)
3758 		return 0;
3759 
3760 	perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3761 
3762 	return 1;
3763 }
3764 
3765 /*
3766  * Enable all of a task's events that have been marked enable-on-exec.
3767  * This expects task == current.
3768  */
3769 static void perf_event_enable_on_exec(int ctxn)
3770 {
3771 	struct perf_event_context *ctx, *clone_ctx = NULL;
3772 	enum event_type_t event_type = 0;
3773 	struct perf_cpu_context *cpuctx;
3774 	struct perf_event *event;
3775 	unsigned long flags;
3776 	int enabled = 0;
3777 
3778 	local_irq_save(flags);
3779 	ctx = current->perf_event_ctxp[ctxn];
3780 	if (!ctx || !ctx->nr_events)
3781 		goto out;
3782 
3783 	cpuctx = __get_cpu_context(ctx);
3784 	perf_ctx_lock(cpuctx, ctx);
3785 	ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3786 	list_for_each_entry(event, &ctx->event_list, event_entry) {
3787 		enabled |= event_enable_on_exec(event, ctx);
3788 		event_type |= get_event_type(event);
3789 	}
3790 
3791 	/*
3792 	 * Unclone and reschedule this context if we enabled any event.
3793 	 */
3794 	if (enabled) {
3795 		clone_ctx = unclone_ctx(ctx);
3796 		ctx_resched(cpuctx, ctx, event_type);
3797 	} else {
3798 		ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3799 	}
3800 	perf_ctx_unlock(cpuctx, ctx);
3801 
3802 out:
3803 	local_irq_restore(flags);
3804 
3805 	if (clone_ctx)
3806 		put_ctx(clone_ctx);
3807 }
3808 
3809 struct perf_read_data {
3810 	struct perf_event *event;
3811 	bool group;
3812 	int ret;
3813 };
3814 
3815 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3816 {
3817 	u16 local_pkg, event_pkg;
3818 
3819 	if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3820 		int local_cpu = smp_processor_id();
3821 
3822 		event_pkg = topology_physical_package_id(event_cpu);
3823 		local_pkg = topology_physical_package_id(local_cpu);
3824 
3825 		if (event_pkg == local_pkg)
3826 			return local_cpu;
3827 	}
3828 
3829 	return event_cpu;
3830 }
3831 
3832 /*
3833  * Cross CPU call to read the hardware event
3834  */
3835 static void __perf_event_read(void *info)
3836 {
3837 	struct perf_read_data *data = info;
3838 	struct perf_event *sub, *event = data->event;
3839 	struct perf_event_context *ctx = event->ctx;
3840 	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3841 	struct pmu *pmu = event->pmu;
3842 
3843 	/*
3844 	 * If this is a task context, we need to check whether it is
3845 	 * the current task context of this cpu.  If not it has been
3846 	 * scheduled out before the smp call arrived.  In that case
3847 	 * event->count would have been updated to a recent sample
3848 	 * when the event was scheduled out.
3849 	 */
3850 	if (ctx->task && cpuctx->task_ctx != ctx)
3851 		return;
3852 
3853 	raw_spin_lock(&ctx->lock);
3854 	if (ctx->is_active & EVENT_TIME) {
3855 		update_context_time(ctx);
3856 		update_cgrp_time_from_event(event);
3857 	}
3858 
3859 	perf_event_update_time(event);
3860 	if (data->group)
3861 		perf_event_update_sibling_time(event);
3862 
3863 	if (event->state != PERF_EVENT_STATE_ACTIVE)
3864 		goto unlock;
3865 
3866 	if (!data->group) {
3867 		pmu->read(event);
3868 		data->ret = 0;
3869 		goto unlock;
3870 	}
3871 
3872 	pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3873 
3874 	pmu->read(event);
3875 
3876 	for_each_sibling_event(sub, event) {
3877 		if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3878 			/*
3879 			 * Use sibling's PMU rather than @event's since
3880 			 * sibling could be on different (eg: software) PMU.
3881 			 */
3882 			sub->pmu->read(sub);
3883 		}
3884 	}
3885 
3886 	data->ret = pmu->commit_txn(pmu);
3887 
3888 unlock:
3889 	raw_spin_unlock(&ctx->lock);
3890 }
3891 
3892 static inline u64 perf_event_count(struct perf_event *event)
3893 {
3894 	return local64_read(&event->count) + atomic64_read(&event->child_count);
3895 }
3896 
3897 /*
3898  * NMI-safe method to read a local event, that is an event that
3899  * is:
3900  *   - either for the current task, or for this CPU
3901  *   - does not have inherit set, for inherited task events
3902  *     will not be local and we cannot read them atomically
3903  *   - must not have a pmu::count method
3904  */
3905 int perf_event_read_local(struct perf_event *event, u64 *value,
3906 			  u64 *enabled, u64 *running)
3907 {
3908 	unsigned long flags;
3909 	int ret = 0;
3910 
3911 	/*
3912 	 * Disabling interrupts avoids all counter scheduling (context
3913 	 * switches, timer based rotation and IPIs).
3914 	 */
3915 	local_irq_save(flags);
3916 
3917 	/*
3918 	 * It must not be an event with inherit set, we cannot read
3919 	 * all child counters from atomic context.
3920 	 */
3921 	if (event->attr.inherit) {
3922 		ret = -EOPNOTSUPP;
3923 		goto out;
3924 	}
3925 
3926 	/* If this is a per-task event, it must be for current */
3927 	if ((event->attach_state & PERF_ATTACH_TASK) &&
3928 	    event->hw.target != current) {
3929 		ret = -EINVAL;
3930 		goto out;
3931 	}
3932 
3933 	/* If this is a per-CPU event, it must be for this CPU */
3934 	if (!(event->attach_state & PERF_ATTACH_TASK) &&
3935 	    event->cpu != smp_processor_id()) {
3936 		ret = -EINVAL;
3937 		goto out;
3938 	}
3939 
3940 	/* If this is a pinned event it must be running on this CPU */
3941 	if (event->attr.pinned && event->oncpu != smp_processor_id()) {
3942 		ret = -EBUSY;
3943 		goto out;
3944 	}
3945 
3946 	/*
3947 	 * If the event is currently on this CPU, its either a per-task event,
3948 	 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3949 	 * oncpu == -1).
3950 	 */
3951 	if (event->oncpu == smp_processor_id())
3952 		event->pmu->read(event);
3953 
3954 	*value = local64_read(&event->count);
3955 	if (enabled || running) {
3956 		u64 now = event->shadow_ctx_time + perf_clock();
3957 		u64 __enabled, __running;
3958 
3959 		__perf_update_times(event, now, &__enabled, &__running);
3960 		if (enabled)
3961 			*enabled = __enabled;
3962 		if (running)
3963 			*running = __running;
3964 	}
3965 out:
3966 	local_irq_restore(flags);
3967 
3968 	return ret;
3969 }
3970 
3971 static int perf_event_read(struct perf_event *event, bool group)
3972 {
3973 	enum perf_event_state state = READ_ONCE(event->state);
3974 	int event_cpu, ret = 0;
3975 
3976 	/*
3977 	 * If event is enabled and currently active on a CPU, update the
3978 	 * value in the event structure:
3979 	 */
3980 again:
3981 	if (state == PERF_EVENT_STATE_ACTIVE) {
3982 		struct perf_read_data data;
3983 
3984 		/*
3985 		 * Orders the ->state and ->oncpu loads such that if we see
3986 		 * ACTIVE we must also see the right ->oncpu.
3987 		 *
3988 		 * Matches the smp_wmb() from event_sched_in().
3989 		 */
3990 		smp_rmb();
3991 
3992 		event_cpu = READ_ONCE(event->oncpu);
3993 		if ((unsigned)event_cpu >= nr_cpu_ids)
3994 			return 0;
3995 
3996 		data = (struct perf_read_data){
3997 			.event = event,
3998 			.group = group,
3999 			.ret = 0,
4000 		};
4001 
4002 		preempt_disable();
4003 		event_cpu = __perf_event_read_cpu(event, event_cpu);
4004 
4005 		/*
4006 		 * Purposely ignore the smp_call_function_single() return
4007 		 * value.
4008 		 *
4009 		 * If event_cpu isn't a valid CPU it means the event got
4010 		 * scheduled out and that will have updated the event count.
4011 		 *
4012 		 * Therefore, either way, we'll have an up-to-date event count
4013 		 * after this.
4014 		 */
4015 		(void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4016 		preempt_enable();
4017 		ret = data.ret;
4018 
4019 	} else if (state == PERF_EVENT_STATE_INACTIVE) {
4020 		struct perf_event_context *ctx = event->ctx;
4021 		unsigned long flags;
4022 
4023 		raw_spin_lock_irqsave(&ctx->lock, flags);
4024 		state = event->state;
4025 		if (state != PERF_EVENT_STATE_INACTIVE) {
4026 			raw_spin_unlock_irqrestore(&ctx->lock, flags);
4027 			goto again;
4028 		}
4029 
4030 		/*
4031 		 * May read while context is not active (e.g., thread is
4032 		 * blocked), in that case we cannot update context time
4033 		 */
4034 		if (ctx->is_active & EVENT_TIME) {
4035 			update_context_time(ctx);
4036 			update_cgrp_time_from_event(event);
4037 		}
4038 
4039 		perf_event_update_time(event);
4040 		if (group)
4041 			perf_event_update_sibling_time(event);
4042 		raw_spin_unlock_irqrestore(&ctx->lock, flags);
4043 	}
4044 
4045 	return ret;
4046 }
4047 
4048 /*
4049  * Initialize the perf_event context in a task_struct:
4050  */
4051 static void __perf_event_init_context(struct perf_event_context *ctx)
4052 {
4053 	raw_spin_lock_init(&ctx->lock);
4054 	mutex_init(&ctx->mutex);
4055 	INIT_LIST_HEAD(&ctx->active_ctx_list);
4056 	perf_event_groups_init(&ctx->pinned_groups);
4057 	perf_event_groups_init(&ctx->flexible_groups);
4058 	INIT_LIST_HEAD(&ctx->event_list);
4059 	INIT_LIST_HEAD(&ctx->pinned_active);
4060 	INIT_LIST_HEAD(&ctx->flexible_active);
4061 	refcount_set(&ctx->refcount, 1);
4062 }
4063 
4064 static struct perf_event_context *
4065 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4066 {
4067 	struct perf_event_context *ctx;
4068 
4069 	ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4070 	if (!ctx)
4071 		return NULL;
4072 
4073 	__perf_event_init_context(ctx);
4074 	if (task) {
4075 		ctx->task = task;
4076 		get_task_struct(task);
4077 	}
4078 	ctx->pmu = pmu;
4079 
4080 	return ctx;
4081 }
4082 
4083 static struct task_struct *
4084 find_lively_task_by_vpid(pid_t vpid)
4085 {
4086 	struct task_struct *task;
4087 
4088 	rcu_read_lock();
4089 	if (!vpid)
4090 		task = current;
4091 	else
4092 		task = find_task_by_vpid(vpid);
4093 	if (task)
4094 		get_task_struct(task);
4095 	rcu_read_unlock();
4096 
4097 	if (!task)
4098 		return ERR_PTR(-ESRCH);
4099 
4100 	return task;
4101 }
4102 
4103 /*
4104  * Returns a matching context with refcount and pincount.
4105  */
4106 static struct perf_event_context *
4107 find_get_context(struct pmu *pmu, struct task_struct *task,
4108 		struct perf_event *event)
4109 {
4110 	struct perf_event_context *ctx, *clone_ctx = NULL;
4111 	struct perf_cpu_context *cpuctx;
4112 	void *task_ctx_data = NULL;
4113 	unsigned long flags;
4114 	int ctxn, err;
4115 	int cpu = event->cpu;
4116 
4117 	if (!task) {
4118 		/* Must be root to operate on a CPU event: */
4119 		if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
4120 			return ERR_PTR(-EACCES);
4121 
4122 		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4123 		ctx = &cpuctx->ctx;
4124 		get_ctx(ctx);
4125 		++ctx->pin_count;
4126 
4127 		return ctx;
4128 	}
4129 
4130 	err = -EINVAL;
4131 	ctxn = pmu->task_ctx_nr;
4132 	if (ctxn < 0)
4133 		goto errout;
4134 
4135 	if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4136 		task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
4137 		if (!task_ctx_data) {
4138 			err = -ENOMEM;
4139 			goto errout;
4140 		}
4141 	}
4142 
4143 retry:
4144 	ctx = perf_lock_task_context(task, ctxn, &flags);
4145 	if (ctx) {
4146 		clone_ctx = unclone_ctx(ctx);
4147 		++ctx->pin_count;
4148 
4149 		if (task_ctx_data && !ctx->task_ctx_data) {
4150 			ctx->task_ctx_data = task_ctx_data;
4151 			task_ctx_data = NULL;
4152 		}
4153 		raw_spin_unlock_irqrestore(&ctx->lock, flags);
4154 
4155 		if (clone_ctx)
4156 			put_ctx(clone_ctx);
4157 	} else {
4158 		ctx = alloc_perf_context(pmu, task);
4159 		err = -ENOMEM;
4160 		if (!ctx)
4161 			goto errout;
4162 
4163 		if (task_ctx_data) {
4164 			ctx->task_ctx_data = task_ctx_data;
4165 			task_ctx_data = NULL;
4166 		}
4167 
4168 		err = 0;
4169 		mutex_lock(&task->perf_event_mutex);
4170 		/*
4171 		 * If it has already passed perf_event_exit_task().
4172 		 * we must see PF_EXITING, it takes this mutex too.
4173 		 */
4174 		if (task->flags & PF_EXITING)
4175 			err = -ESRCH;
4176 		else if (task->perf_event_ctxp[ctxn])
4177 			err = -EAGAIN;
4178 		else {
4179 			get_ctx(ctx);
4180 			++ctx->pin_count;
4181 			rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4182 		}
4183 		mutex_unlock(&task->perf_event_mutex);
4184 
4185 		if (unlikely(err)) {
4186 			put_ctx(ctx);
4187 
4188 			if (err == -EAGAIN)
4189 				goto retry;
4190 			goto errout;
4191 		}
4192 	}
4193 
4194 	kfree(task_ctx_data);
4195 	return ctx;
4196 
4197 errout:
4198 	kfree(task_ctx_data);
4199 	return ERR_PTR(err);
4200 }
4201 
4202 static void perf_event_free_filter(struct perf_event *event);
4203 static void perf_event_free_bpf_prog(struct perf_event *event);
4204 
4205 static void free_event_rcu(struct rcu_head *head)
4206 {
4207 	struct perf_event *event;
4208 
4209 	event = container_of(head, struct perf_event, rcu_head);
4210 	if (event->ns)
4211 		put_pid_ns(event->ns);
4212 	perf_event_free_filter(event);
4213 	kfree(event);
4214 }
4215 
4216 static void ring_buffer_attach(struct perf_event *event,
4217 			       struct ring_buffer *rb);
4218 
4219 static void detach_sb_event(struct perf_event *event)
4220 {
4221 	struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4222 
4223 	raw_spin_lock(&pel->lock);
4224 	list_del_rcu(&event->sb_list);
4225 	raw_spin_unlock(&pel->lock);
4226 }
4227 
4228 static bool is_sb_event(struct perf_event *event)
4229 {
4230 	struct perf_event_attr *attr = &event->attr;
4231 
4232 	if (event->parent)
4233 		return false;
4234 
4235 	if (event->attach_state & PERF_ATTACH_TASK)
4236 		return false;
4237 
4238 	if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4239 	    attr->comm || attr->comm_exec ||
4240 	    attr->task || attr->ksymbol ||
4241 	    attr->context_switch)
4242 		return true;
4243 	return false;
4244 }
4245 
4246 static void unaccount_pmu_sb_event(struct perf_event *event)
4247 {
4248 	if (is_sb_event(event))
4249 		detach_sb_event(event);
4250 }
4251 
4252 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4253 {
4254 	if (event->parent)
4255 		return;
4256 
4257 	if (is_cgroup_event(event))
4258 		atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4259 }
4260 
4261 #ifdef CONFIG_NO_HZ_FULL
4262 static DEFINE_SPINLOCK(nr_freq_lock);
4263 #endif
4264 
4265 static void unaccount_freq_event_nohz(void)
4266 {
4267 #ifdef CONFIG_NO_HZ_FULL
4268 	spin_lock(&nr_freq_lock);
4269 	if (atomic_dec_and_test(&nr_freq_events))
4270 		tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4271 	spin_unlock(&nr_freq_lock);
4272 #endif
4273 }
4274 
4275 static void unaccount_freq_event(void)
4276 {
4277 	if (tick_nohz_full_enabled())
4278 		unaccount_freq_event_nohz();
4279 	else
4280 		atomic_dec(&nr_freq_events);
4281 }
4282 
4283 static void unaccount_event(struct perf_event *event)
4284 {
4285 	bool dec = false;
4286 
4287 	if (event->parent)
4288 		return;
4289 
4290 	if (event->attach_state & PERF_ATTACH_TASK)
4291 		dec = true;
4292 	if (event->attr.mmap || event->attr.mmap_data)
4293 		atomic_dec(&nr_mmap_events);
4294 	if (event->attr.comm)
4295 		atomic_dec(&nr_comm_events);
4296 	if (event->attr.namespaces)
4297 		atomic_dec(&nr_namespaces_events);
4298 	if (event->attr.task)
4299 		atomic_dec(&nr_task_events);
4300 	if (event->attr.freq)
4301 		unaccount_freq_event();
4302 	if (event->attr.context_switch) {
4303 		dec = true;
4304 		atomic_dec(&nr_switch_events);
4305 	}
4306 	if (is_cgroup_event(event))
4307 		dec = true;
4308 	if (has_branch_stack(event))
4309 		dec = true;
4310 	if (event->attr.ksymbol)
4311 		atomic_dec(&nr_ksymbol_events);
4312 	if (event->attr.bpf_event)
4313 		atomic_dec(&nr_bpf_events);
4314 
4315 	if (dec) {
4316 		if (!atomic_add_unless(&perf_sched_count, -1, 1))
4317 			schedule_delayed_work(&perf_sched_work, HZ);
4318 	}
4319 
4320 	unaccount_event_cpu(event, event->cpu);
4321 
4322 	unaccount_pmu_sb_event(event);
4323 }
4324 
4325 static void perf_sched_delayed(struct work_struct *work)
4326 {
4327 	mutex_lock(&perf_sched_mutex);
4328 	if (atomic_dec_and_test(&perf_sched_count))
4329 		static_branch_disable(&perf_sched_events);
4330 	mutex_unlock(&perf_sched_mutex);
4331 }
4332 
4333 /*
4334  * The following implement mutual exclusion of events on "exclusive" pmus
4335  * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4336  * at a time, so we disallow creating events that might conflict, namely:
4337  *
4338  *  1) cpu-wide events in the presence of per-task events,
4339  *  2) per-task events in the presence of cpu-wide events,
4340  *  3) two matching events on the same context.
4341  *
4342  * The former two cases are handled in the allocation path (perf_event_alloc(),
4343  * _free_event()), the latter -- before the first perf_install_in_context().
4344  */
4345 static int exclusive_event_init(struct perf_event *event)
4346 {
4347 	struct pmu *pmu = event->pmu;
4348 
4349 	if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4350 		return 0;
4351 
4352 	/*
4353 	 * Prevent co-existence of per-task and cpu-wide events on the
4354 	 * same exclusive pmu.
4355 	 *
4356 	 * Negative pmu::exclusive_cnt means there are cpu-wide
4357 	 * events on this "exclusive" pmu, positive means there are
4358 	 * per-task events.
4359 	 *
4360 	 * Since this is called in perf_event_alloc() path, event::ctx
4361 	 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4362 	 * to mean "per-task event", because unlike other attach states it
4363 	 * never gets cleared.
4364 	 */
4365 	if (event->attach_state & PERF_ATTACH_TASK) {
4366 		if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4367 			return -EBUSY;
4368 	} else {
4369 		if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4370 			return -EBUSY;
4371 	}
4372 
4373 	return 0;
4374 }
4375 
4376 static void exclusive_event_destroy(struct perf_event *event)
4377 {
4378 	struct pmu *pmu = event->pmu;
4379 
4380 	if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4381 		return;
4382 
4383 	/* see comment in exclusive_event_init() */
4384 	if (event->attach_state & PERF_ATTACH_TASK)
4385 		atomic_dec(&pmu->exclusive_cnt);
4386 	else
4387 		atomic_inc(&pmu->exclusive_cnt);
4388 }
4389 
4390 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4391 {
4392 	if ((e1->pmu == e2->pmu) &&
4393 	    (e1->cpu == e2->cpu ||
4394 	     e1->cpu == -1 ||
4395 	     e2->cpu == -1))
4396 		return true;
4397 	return false;
4398 }
4399 
4400 /* Called under the same ctx::mutex as perf_install_in_context() */
4401 static bool exclusive_event_installable(struct perf_event *event,
4402 					struct perf_event_context *ctx)
4403 {
4404 	struct perf_event *iter_event;
4405 	struct pmu *pmu = event->pmu;
4406 
4407 	if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4408 		return true;
4409 
4410 	list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4411 		if (exclusive_event_match(iter_event, event))
4412 			return false;
4413 	}
4414 
4415 	return true;
4416 }
4417 
4418 static void perf_addr_filters_splice(struct perf_event *event,
4419 				       struct list_head *head);
4420 
4421 static void _free_event(struct perf_event *event)
4422 {
4423 	irq_work_sync(&event->pending);
4424 
4425 	unaccount_event(event);
4426 
4427 	if (event->rb) {
4428 		/*
4429 		 * Can happen when we close an event with re-directed output.
4430 		 *
4431 		 * Since we have a 0 refcount, perf_mmap_close() will skip
4432 		 * over us; possibly making our ring_buffer_put() the last.
4433 		 */
4434 		mutex_lock(&event->mmap_mutex);
4435 		ring_buffer_attach(event, NULL);
4436 		mutex_unlock(&event->mmap_mutex);
4437 	}
4438 
4439 	if (is_cgroup_event(event))
4440 		perf_detach_cgroup(event);
4441 
4442 	if (!event->parent) {
4443 		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4444 			put_callchain_buffers();
4445 	}
4446 
4447 	perf_event_free_bpf_prog(event);
4448 	perf_addr_filters_splice(event, NULL);
4449 	kfree(event->addr_filter_ranges);
4450 
4451 	if (event->destroy)
4452 		event->destroy(event);
4453 
4454 	if (event->ctx)
4455 		put_ctx(event->ctx);
4456 
4457 	if (event->hw.target)
4458 		put_task_struct(event->hw.target);
4459 
4460 	exclusive_event_destroy(event);
4461 	module_put(event->pmu->module);
4462 
4463 	call_rcu(&event->rcu_head, free_event_rcu);
4464 }
4465 
4466 /*
4467  * Used to free events which have a known refcount of 1, such as in error paths
4468  * where the event isn't exposed yet and inherited events.
4469  */
4470 static void free_event(struct perf_event *event)
4471 {
4472 	if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4473 				"unexpected event refcount: %ld; ptr=%p\n",
4474 				atomic_long_read(&event->refcount), event)) {
4475 		/* leak to avoid use-after-free */
4476 		return;
4477 	}
4478 
4479 	_free_event(event);
4480 }
4481 
4482 /*
4483  * Remove user event from the owner task.
4484  */
4485 static void perf_remove_from_owner(struct perf_event *event)
4486 {
4487 	struct task_struct *owner;
4488 
4489 	rcu_read_lock();
4490 	/*
4491 	 * Matches the smp_store_release() in perf_event_exit_task(). If we
4492 	 * observe !owner it means the list deletion is complete and we can
4493 	 * indeed free this event, otherwise we need to serialize on
4494 	 * owner->perf_event_mutex.
4495 	 */
4496 	owner = READ_ONCE(event->owner);
4497 	if (owner) {
4498 		/*
4499 		 * Since delayed_put_task_struct() also drops the last
4500 		 * task reference we can safely take a new reference
4501 		 * while holding the rcu_read_lock().
4502 		 */
4503 		get_task_struct(owner);
4504 	}
4505 	rcu_read_unlock();
4506 
4507 	if (owner) {
4508 		/*
4509 		 * If we're here through perf_event_exit_task() we're already
4510 		 * holding ctx->mutex which would be an inversion wrt. the
4511 		 * normal lock order.
4512 		 *
4513 		 * However we can safely take this lock because its the child
4514 		 * ctx->mutex.
4515 		 */
4516 		mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4517 
4518 		/*
4519 		 * We have to re-check the event->owner field, if it is cleared
4520 		 * we raced with perf_event_exit_task(), acquiring the mutex
4521 		 * ensured they're done, and we can proceed with freeing the
4522 		 * event.
4523 		 */
4524 		if (event->owner) {
4525 			list_del_init(&event->owner_entry);
4526 			smp_store_release(&event->owner, NULL);
4527 		}
4528 		mutex_unlock(&owner->perf_event_mutex);
4529 		put_task_struct(owner);
4530 	}
4531 }
4532 
4533 static void put_event(struct perf_event *event)
4534 {
4535 	if (!atomic_long_dec_and_test(&event->refcount))
4536 		return;
4537 
4538 	_free_event(event);
4539 }
4540 
4541 /*
4542  * Kill an event dead; while event:refcount will preserve the event
4543  * object, it will not preserve its functionality. Once the last 'user'
4544  * gives up the object, we'll destroy the thing.
4545  */
4546 int perf_event_release_kernel(struct perf_event *event)
4547 {
4548 	struct perf_event_context *ctx = event->ctx;
4549 	struct perf_event *child, *tmp;
4550 	LIST_HEAD(free_list);
4551 
4552 	/*
4553 	 * If we got here through err_file: fput(event_file); we will not have
4554 	 * attached to a context yet.
4555 	 */
4556 	if (!ctx) {
4557 		WARN_ON_ONCE(event->attach_state &
4558 				(PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4559 		goto no_ctx;
4560 	}
4561 
4562 	if (!is_kernel_event(event))
4563 		perf_remove_from_owner(event);
4564 
4565 	ctx = perf_event_ctx_lock(event);
4566 	WARN_ON_ONCE(ctx->parent_ctx);
4567 	perf_remove_from_context(event, DETACH_GROUP);
4568 
4569 	raw_spin_lock_irq(&ctx->lock);
4570 	/*
4571 	 * Mark this event as STATE_DEAD, there is no external reference to it
4572 	 * anymore.
4573 	 *
4574 	 * Anybody acquiring event->child_mutex after the below loop _must_
4575 	 * also see this, most importantly inherit_event() which will avoid
4576 	 * placing more children on the list.
4577 	 *
4578 	 * Thus this guarantees that we will in fact observe and kill _ALL_
4579 	 * child events.
4580 	 */
4581 	event->state = PERF_EVENT_STATE_DEAD;
4582 	raw_spin_unlock_irq(&ctx->lock);
4583 
4584 	perf_event_ctx_unlock(event, ctx);
4585 
4586 again:
4587 	mutex_lock(&event->child_mutex);
4588 	list_for_each_entry(child, &event->child_list, child_list) {
4589 
4590 		/*
4591 		 * Cannot change, child events are not migrated, see the
4592 		 * comment with perf_event_ctx_lock_nested().
4593 		 */
4594 		ctx = READ_ONCE(child->ctx);
4595 		/*
4596 		 * Since child_mutex nests inside ctx::mutex, we must jump
4597 		 * through hoops. We start by grabbing a reference on the ctx.
4598 		 *
4599 		 * Since the event cannot get freed while we hold the
4600 		 * child_mutex, the context must also exist and have a !0
4601 		 * reference count.
4602 		 */
4603 		get_ctx(ctx);
4604 
4605 		/*
4606 		 * Now that we have a ctx ref, we can drop child_mutex, and
4607 		 * acquire ctx::mutex without fear of it going away. Then we
4608 		 * can re-acquire child_mutex.
4609 		 */
4610 		mutex_unlock(&event->child_mutex);
4611 		mutex_lock(&ctx->mutex);
4612 		mutex_lock(&event->child_mutex);
4613 
4614 		/*
4615 		 * Now that we hold ctx::mutex and child_mutex, revalidate our
4616 		 * state, if child is still the first entry, it didn't get freed
4617 		 * and we can continue doing so.
4618 		 */
4619 		tmp = list_first_entry_or_null(&event->child_list,
4620 					       struct perf_event, child_list);
4621 		if (tmp == child) {
4622 			perf_remove_from_context(child, DETACH_GROUP);
4623 			list_move(&child->child_list, &free_list);
4624 			/*
4625 			 * This matches the refcount bump in inherit_event();
4626 			 * this can't be the last reference.
4627 			 */
4628 			put_event(event);
4629 		}
4630 
4631 		mutex_unlock(&event->child_mutex);
4632 		mutex_unlock(&ctx->mutex);
4633 		put_ctx(ctx);
4634 		goto again;
4635 	}
4636 	mutex_unlock(&event->child_mutex);
4637 
4638 	list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4639 		list_del(&child->child_list);
4640 		free_event(child);
4641 	}
4642 
4643 no_ctx:
4644 	put_event(event); /* Must be the 'last' reference */
4645 	return 0;
4646 }
4647 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4648 
4649 /*
4650  * Called when the last reference to the file is gone.
4651  */
4652 static int perf_release(struct inode *inode, struct file *file)
4653 {
4654 	perf_event_release_kernel(file->private_data);
4655 	return 0;
4656 }
4657 
4658 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4659 {
4660 	struct perf_event *child;
4661 	u64 total = 0;
4662 
4663 	*enabled = 0;
4664 	*running = 0;
4665 
4666 	mutex_lock(&event->child_mutex);
4667 
4668 	(void)perf_event_read(event, false);
4669 	total += perf_event_count(event);
4670 
4671 	*enabled += event->total_time_enabled +
4672 			atomic64_read(&event->child_total_time_enabled);
4673 	*running += event->total_time_running +
4674 			atomic64_read(&event->child_total_time_running);
4675 
4676 	list_for_each_entry(child, &event->child_list, child_list) {
4677 		(void)perf_event_read(child, false);
4678 		total += perf_event_count(child);
4679 		*enabled += child->total_time_enabled;
4680 		*running += child->total_time_running;
4681 	}
4682 	mutex_unlock(&event->child_mutex);
4683 
4684 	return total;
4685 }
4686 
4687 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4688 {
4689 	struct perf_event_context *ctx;
4690 	u64 count;
4691 
4692 	ctx = perf_event_ctx_lock(event);
4693 	count = __perf_event_read_value(event, enabled, running);
4694 	perf_event_ctx_unlock(event, ctx);
4695 
4696 	return count;
4697 }
4698 EXPORT_SYMBOL_GPL(perf_event_read_value);
4699 
4700 static int __perf_read_group_add(struct perf_event *leader,
4701 					u64 read_format, u64 *values)
4702 {
4703 	struct perf_event_context *ctx = leader->ctx;
4704 	struct perf_event *sub;
4705 	unsigned long flags;
4706 	int n = 1; /* skip @nr */
4707 	int ret;
4708 
4709 	ret = perf_event_read(leader, true);
4710 	if (ret)
4711 		return ret;
4712 
4713 	raw_spin_lock_irqsave(&ctx->lock, flags);
4714 
4715 	/*
4716 	 * Since we co-schedule groups, {enabled,running} times of siblings
4717 	 * will be identical to those of the leader, so we only publish one
4718 	 * set.
4719 	 */
4720 	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4721 		values[n++] += leader->total_time_enabled +
4722 			atomic64_read(&leader->child_total_time_enabled);
4723 	}
4724 
4725 	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4726 		values[n++] += leader->total_time_running +
4727 			atomic64_read(&leader->child_total_time_running);
4728 	}
4729 
4730 	/*
4731 	 * Write {count,id} tuples for every sibling.
4732 	 */
4733 	values[n++] += perf_event_count(leader);
4734 	if (read_format & PERF_FORMAT_ID)
4735 		values[n++] = primary_event_id(leader);
4736 
4737 	for_each_sibling_event(sub, leader) {
4738 		values[n++] += perf_event_count(sub);
4739 		if (read_format & PERF_FORMAT_ID)
4740 			values[n++] = primary_event_id(sub);
4741 	}
4742 
4743 	raw_spin_unlock_irqrestore(&ctx->lock, flags);
4744 	return 0;
4745 }
4746 
4747 static int perf_read_group(struct perf_event *event,
4748 				   u64 read_format, char __user *buf)
4749 {
4750 	struct perf_event *leader = event->group_leader, *child;
4751 	struct perf_event_context *ctx = leader->ctx;
4752 	int ret;
4753 	u64 *values;
4754 
4755 	lockdep_assert_held(&ctx->mutex);
4756 
4757 	values = kzalloc(event->read_size, GFP_KERNEL);
4758 	if (!values)
4759 		return -ENOMEM;
4760 
4761 	values[0] = 1 + leader->nr_siblings;
4762 
4763 	/*
4764 	 * By locking the child_mutex of the leader we effectively
4765 	 * lock the child list of all siblings.. XXX explain how.
4766 	 */
4767 	mutex_lock(&leader->child_mutex);
4768 
4769 	ret = __perf_read_group_add(leader, read_format, values);
4770 	if (ret)
4771 		goto unlock;
4772 
4773 	list_for_each_entry(child, &leader->child_list, child_list) {
4774 		ret = __perf_read_group_add(child, read_format, values);
4775 		if (ret)
4776 			goto unlock;
4777 	}
4778 
4779 	mutex_unlock(&leader->child_mutex);
4780 
4781 	ret = event->read_size;
4782 	if (copy_to_user(buf, values, event->read_size))
4783 		ret = -EFAULT;
4784 	goto out;
4785 
4786 unlock:
4787 	mutex_unlock(&leader->child_mutex);
4788 out:
4789 	kfree(values);
4790 	return ret;
4791 }
4792 
4793 static int perf_read_one(struct perf_event *event,
4794 				 u64 read_format, char __user *buf)
4795 {
4796 	u64 enabled, running;
4797 	u64 values[4];
4798 	int n = 0;
4799 
4800 	values[n++] = __perf_event_read_value(event, &enabled, &running);
4801 	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4802 		values[n++] = enabled;
4803 	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4804 		values[n++] = running;
4805 	if (read_format & PERF_FORMAT_ID)
4806 		values[n++] = primary_event_id(event);
4807 
4808 	if (copy_to_user(buf, values, n * sizeof(u64)))
4809 		return -EFAULT;
4810 
4811 	return n * sizeof(u64);
4812 }
4813 
4814 static bool is_event_hup(struct perf_event *event)
4815 {
4816 	bool no_children;
4817 
4818 	if (event->state > PERF_EVENT_STATE_EXIT)
4819 		return false;
4820 
4821 	mutex_lock(&event->child_mutex);
4822 	no_children = list_empty(&event->child_list);
4823 	mutex_unlock(&event->child_mutex);
4824 	return no_children;
4825 }
4826 
4827 /*
4828  * Read the performance event - simple non blocking version for now
4829  */
4830 static ssize_t
4831 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4832 {
4833 	u64 read_format = event->attr.read_format;
4834 	int ret;
4835 
4836 	/*
4837 	 * Return end-of-file for a read on an event that is in
4838 	 * error state (i.e. because it was pinned but it couldn't be
4839 	 * scheduled on to the CPU at some point).
4840 	 */
4841 	if (event->state == PERF_EVENT_STATE_ERROR)
4842 		return 0;
4843 
4844 	if (count < event->read_size)
4845 		return -ENOSPC;
4846 
4847 	WARN_ON_ONCE(event->ctx->parent_ctx);
4848 	if (read_format & PERF_FORMAT_GROUP)
4849 		ret = perf_read_group(event, read_format, buf);
4850 	else
4851 		ret = perf_read_one(event, read_format, buf);
4852 
4853 	return ret;
4854 }
4855 
4856 static ssize_t
4857 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4858 {
4859 	struct perf_event *event = file->private_data;
4860 	struct perf_event_context *ctx;
4861 	int ret;
4862 
4863 	ctx = perf_event_ctx_lock(event);
4864 	ret = __perf_read(event, buf, count);
4865 	perf_event_ctx_unlock(event, ctx);
4866 
4867 	return ret;
4868 }
4869 
4870 static __poll_t perf_poll(struct file *file, poll_table *wait)
4871 {
4872 	struct perf_event *event = file->private_data;
4873 	struct ring_buffer *rb;
4874 	__poll_t events = EPOLLHUP;
4875 
4876 	poll_wait(file, &event->waitq, wait);
4877 
4878 	if (is_event_hup(event))
4879 		return events;
4880 
4881 	/*
4882 	 * Pin the event->rb by taking event->mmap_mutex; otherwise
4883 	 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4884 	 */
4885 	mutex_lock(&event->mmap_mutex);
4886 	rb = event->rb;
4887 	if (rb)
4888 		events = atomic_xchg(&rb->poll, 0);
4889 	mutex_unlock(&event->mmap_mutex);
4890 	return events;
4891 }
4892 
4893 static void _perf_event_reset(struct perf_event *event)
4894 {
4895 	(void)perf_event_read(event, false);
4896 	local64_set(&event->count, 0);
4897 	perf_event_update_userpage(event);
4898 }
4899 
4900 /*
4901  * Holding the top-level event's child_mutex means that any
4902  * descendant process that has inherited this event will block
4903  * in perf_event_exit_event() if it goes to exit, thus satisfying the
4904  * task existence requirements of perf_event_enable/disable.
4905  */
4906 static void perf_event_for_each_child(struct perf_event *event,
4907 					void (*func)(struct perf_event *))
4908 {
4909 	struct perf_event *child;
4910 
4911 	WARN_ON_ONCE(event->ctx->parent_ctx);
4912 
4913 	mutex_lock(&event->child_mutex);
4914 	func(event);
4915 	list_for_each_entry(child, &event->child_list, child_list)
4916 		func(child);
4917 	mutex_unlock(&event->child_mutex);
4918 }
4919 
4920 static void perf_event_for_each(struct perf_event *event,
4921 				  void (*func)(struct perf_event *))
4922 {
4923 	struct perf_event_context *ctx = event->ctx;
4924 	struct perf_event *sibling;
4925 
4926 	lockdep_assert_held(&ctx->mutex);
4927 
4928 	event = event->group_leader;
4929 
4930 	perf_event_for_each_child(event, func);
4931 	for_each_sibling_event(sibling, event)
4932 		perf_event_for_each_child(sibling, func);
4933 }
4934 
4935 static void __perf_event_period(struct perf_event *event,
4936 				struct perf_cpu_context *cpuctx,
4937 				struct perf_event_context *ctx,
4938 				void *info)
4939 {
4940 	u64 value = *((u64 *)info);
4941 	bool active;
4942 
4943 	if (event->attr.freq) {
4944 		event->attr.sample_freq = value;
4945 	} else {
4946 		event->attr.sample_period = value;
4947 		event->hw.sample_period = value;
4948 	}
4949 
4950 	active = (event->state == PERF_EVENT_STATE_ACTIVE);
4951 	if (active) {
4952 		perf_pmu_disable(ctx->pmu);
4953 		/*
4954 		 * We could be throttled; unthrottle now to avoid the tick
4955 		 * trying to unthrottle while we already re-started the event.
4956 		 */
4957 		if (event->hw.interrupts == MAX_INTERRUPTS) {
4958 			event->hw.interrupts = 0;
4959 			perf_log_throttle(event, 1);
4960 		}
4961 		event->pmu->stop(event, PERF_EF_UPDATE);
4962 	}
4963 
4964 	local64_set(&event->hw.period_left, 0);
4965 
4966 	if (active) {
4967 		event->pmu->start(event, PERF_EF_RELOAD);
4968 		perf_pmu_enable(ctx->pmu);
4969 	}
4970 }
4971 
4972 static int perf_event_check_period(struct perf_event *event, u64 value)
4973 {
4974 	return event->pmu->check_period(event, value);
4975 }
4976 
4977 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4978 {
4979 	u64 value;
4980 
4981 	if (!is_sampling_event(event))
4982 		return -EINVAL;
4983 
4984 	if (copy_from_user(&value, arg, sizeof(value)))
4985 		return -EFAULT;
4986 
4987 	if (!value)
4988 		return -EINVAL;
4989 
4990 	if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4991 		return -EINVAL;
4992 
4993 	if (perf_event_check_period(event, value))
4994 		return -EINVAL;
4995 
4996 	event_function_call(event, __perf_event_period, &value);
4997 
4998 	return 0;
4999 }
5000 
5001 static const struct file_operations perf_fops;
5002 
5003 static inline int perf_fget_light(int fd, struct fd *p)
5004 {
5005 	struct fd f = fdget(fd);
5006 	if (!f.file)
5007 		return -EBADF;
5008 
5009 	if (f.file->f_op != &perf_fops) {
5010 		fdput(f);
5011 		return -EBADF;
5012 	}
5013 	*p = f;
5014 	return 0;
5015 }
5016 
5017 static int perf_event_set_output(struct perf_event *event,
5018 				 struct perf_event *output_event);
5019 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5020 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5021 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5022 			  struct perf_event_attr *attr);
5023 
5024 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5025 {
5026 	void (*func)(struct perf_event *);
5027 	u32 flags = arg;
5028 
5029 	switch (cmd) {
5030 	case PERF_EVENT_IOC_ENABLE:
5031 		func = _perf_event_enable;
5032 		break;
5033 	case PERF_EVENT_IOC_DISABLE:
5034 		func = _perf_event_disable;
5035 		break;
5036 	case PERF_EVENT_IOC_RESET:
5037 		func = _perf_event_reset;
5038 		break;
5039 
5040 	case PERF_EVENT_IOC_REFRESH:
5041 		return _perf_event_refresh(event, arg);
5042 
5043 	case PERF_EVENT_IOC_PERIOD:
5044 		return perf_event_period(event, (u64 __user *)arg);
5045 
5046 	case PERF_EVENT_IOC_ID:
5047 	{
5048 		u64 id = primary_event_id(event);
5049 
5050 		if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5051 			return -EFAULT;
5052 		return 0;
5053 	}
5054 
5055 	case PERF_EVENT_IOC_SET_OUTPUT:
5056 	{
5057 		int ret;
5058 		if (arg != -1) {
5059 			struct perf_event *output_event;
5060 			struct fd output;
5061 			ret = perf_fget_light(arg, &output);
5062 			if (ret)
5063 				return ret;
5064 			output_event = output.file->private_data;
5065 			ret = perf_event_set_output(event, output_event);
5066 			fdput(output);
5067 		} else {
5068 			ret = perf_event_set_output(event, NULL);
5069 		}
5070 		return ret;
5071 	}
5072 
5073 	case PERF_EVENT_IOC_SET_FILTER:
5074 		return perf_event_set_filter(event, (void __user *)arg);
5075 
5076 	case PERF_EVENT_IOC_SET_BPF:
5077 		return perf_event_set_bpf_prog(event, arg);
5078 
5079 	case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5080 		struct ring_buffer *rb;
5081 
5082 		rcu_read_lock();
5083 		rb = rcu_dereference(event->rb);
5084 		if (!rb || !rb->nr_pages) {
5085 			rcu_read_unlock();
5086 			return -EINVAL;
5087 		}
5088 		rb_toggle_paused(rb, !!arg);
5089 		rcu_read_unlock();
5090 		return 0;
5091 	}
5092 
5093 	case PERF_EVENT_IOC_QUERY_BPF:
5094 		return perf_event_query_prog_array(event, (void __user *)arg);
5095 
5096 	case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5097 		struct perf_event_attr new_attr;
5098 		int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5099 					 &new_attr);
5100 
5101 		if (err)
5102 			return err;
5103 
5104 		return perf_event_modify_attr(event,  &new_attr);
5105 	}
5106 	default:
5107 		return -ENOTTY;
5108 	}
5109 
5110 	if (flags & PERF_IOC_FLAG_GROUP)
5111 		perf_event_for_each(event, func);
5112 	else
5113 		perf_event_for_each_child(event, func);
5114 
5115 	return 0;
5116 }
5117 
5118 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5119 {
5120 	struct perf_event *event = file->private_data;
5121 	struct perf_event_context *ctx;
5122 	long ret;
5123 
5124 	ctx = perf_event_ctx_lock(event);
5125 	ret = _perf_ioctl(event, cmd, arg);
5126 	perf_event_ctx_unlock(event, ctx);
5127 
5128 	return ret;
5129 }
5130 
5131 #ifdef CONFIG_COMPAT
5132 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5133 				unsigned long arg)
5134 {
5135 	switch (_IOC_NR(cmd)) {
5136 	case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5137 	case _IOC_NR(PERF_EVENT_IOC_ID):
5138 	case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5139 	case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5140 		/* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5141 		if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5142 			cmd &= ~IOCSIZE_MASK;
5143 			cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5144 		}
5145 		break;
5146 	}
5147 	return perf_ioctl(file, cmd, arg);
5148 }
5149 #else
5150 # define perf_compat_ioctl NULL
5151 #endif
5152 
5153 int perf_event_task_enable(void)
5154 {
5155 	struct perf_event_context *ctx;
5156 	struct perf_event *event;
5157 
5158 	mutex_lock(&current->perf_event_mutex);
5159 	list_for_each_entry(event, &current->perf_event_list, owner_entry) {
5160 		ctx = perf_event_ctx_lock(event);
5161 		perf_event_for_each_child(event, _perf_event_enable);
5162 		perf_event_ctx_unlock(event, ctx);
5163 	}
5164 	mutex_unlock(&current->perf_event_mutex);
5165 
5166 	return 0;
5167 }
5168 
5169 int perf_event_task_disable(void)
5170 {
5171 	struct perf_event_context *ctx;
5172 	struct perf_event *event;
5173 
5174 	mutex_lock(&current->perf_event_mutex);
5175 	list_for_each_entry(event, &current->perf_event_list, owner_entry) {
5176 		ctx = perf_event_ctx_lock(event);
5177 		perf_event_for_each_child(event, _perf_event_disable);
5178 		perf_event_ctx_unlock(event, ctx);
5179 	}
5180 	mutex_unlock(&current->perf_event_mutex);
5181 
5182 	return 0;
5183 }
5184 
5185 static int perf_event_index(struct perf_event *event)
5186 {
5187 	if (event->hw.state & PERF_HES_STOPPED)
5188 		return 0;
5189 
5190 	if (event->state != PERF_EVENT_STATE_ACTIVE)
5191 		return 0;
5192 
5193 	return event->pmu->event_idx(event);
5194 }
5195 
5196 static void calc_timer_values(struct perf_event *event,
5197 				u64 *now,
5198 				u64 *enabled,
5199 				u64 *running)
5200 {
5201 	u64 ctx_time;
5202 
5203 	*now = perf_clock();
5204 	ctx_time = event->shadow_ctx_time + *now;
5205 	__perf_update_times(event, ctx_time, enabled, running);
5206 }
5207 
5208 static void perf_event_init_userpage(struct perf_event *event)
5209 {
5210 	struct perf_event_mmap_page *userpg;
5211 	struct ring_buffer *rb;
5212 
5213 	rcu_read_lock();
5214 	rb = rcu_dereference(event->rb);
5215 	if (!rb)
5216 		goto unlock;
5217 
5218 	userpg = rb->user_page;
5219 
5220 	/* Allow new userspace to detect that bit 0 is deprecated */
5221 	userpg->cap_bit0_is_deprecated = 1;
5222 	userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5223 	userpg->data_offset = PAGE_SIZE;
5224 	userpg->data_size = perf_data_size(rb);
5225 
5226 unlock:
5227 	rcu_read_unlock();
5228 }
5229 
5230 void __weak arch_perf_update_userpage(
5231 	struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5232 {
5233 }
5234 
5235 /*
5236  * Callers need to ensure there can be no nesting of this function, otherwise
5237  * the seqlock logic goes bad. We can not serialize this because the arch
5238  * code calls this from NMI context.
5239  */
5240 void perf_event_update_userpage(struct perf_event *event)
5241 {
5242 	struct perf_event_mmap_page *userpg;
5243 	struct ring_buffer *rb;
5244 	u64 enabled, running, now;
5245 
5246 	rcu_read_lock();
5247 	rb = rcu_dereference(event->rb);
5248 	if (!rb)
5249 		goto unlock;
5250 
5251 	/*
5252 	 * compute total_time_enabled, total_time_running
5253 	 * based on snapshot values taken when the event
5254 	 * was last scheduled in.
5255 	 *
5256 	 * we cannot simply called update_context_time()
5257 	 * because of locking issue as we can be called in
5258 	 * NMI context
5259 	 */
5260 	calc_timer_values(event, &now, &enabled, &running);
5261 
5262 	userpg = rb->user_page;
5263 	/*
5264 	 * Disable preemption to guarantee consistent time stamps are stored to
5265 	 * the user page.
5266 	 */
5267 	preempt_disable();
5268 	++userpg->lock;
5269 	barrier();
5270 	userpg->index = perf_event_index(event);
5271 	userpg->offset = perf_event_count(event);
5272 	if (userpg->index)
5273 		userpg->offset -= local64_read(&event->hw.prev_count);
5274 
5275 	userpg->time_enabled = enabled +
5276 			atomic64_read(&event->child_total_time_enabled);
5277 
5278 	userpg->time_running = running +
5279 			atomic64_read(&event->child_total_time_running);
5280 
5281 	arch_perf_update_userpage(event, userpg, now);
5282 
5283 	barrier();
5284 	++userpg->lock;
5285 	preempt_enable();
5286 unlock:
5287 	rcu_read_unlock();
5288 }
5289 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5290 
5291 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5292 {
5293 	struct perf_event *event = vmf->vma->vm_file->private_data;
5294 	struct ring_buffer *rb;
5295 	vm_fault_t ret = VM_FAULT_SIGBUS;
5296 
5297 	if (vmf->flags & FAULT_FLAG_MKWRITE) {
5298 		if (vmf->pgoff == 0)
5299 			ret = 0;
5300 		return ret;
5301 	}
5302 
5303 	rcu_read_lock();
5304 	rb = rcu_dereference(event->rb);
5305 	if (!rb)
5306 		goto unlock;
5307 
5308 	if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5309 		goto unlock;
5310 
5311 	vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5312 	if (!vmf->page)
5313 		goto unlock;
5314 
5315 	get_page(vmf->page);
5316 	vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5317 	vmf->page->index   = vmf->pgoff;
5318 
5319 	ret = 0;
5320 unlock:
5321 	rcu_read_unlock();
5322 
5323 	return ret;
5324 }
5325 
5326 static void ring_buffer_attach(struct perf_event *event,
5327 			       struct ring_buffer *rb)
5328 {
5329 	struct ring_buffer *old_rb = NULL;
5330 	unsigned long flags;
5331 
5332 	if (event->rb) {
5333 		/*
5334 		 * Should be impossible, we set this when removing
5335 		 * event->rb_entry and wait/clear when adding event->rb_entry.
5336 		 */
5337 		WARN_ON_ONCE(event->rcu_pending);
5338 
5339 		old_rb = event->rb;
5340 		spin_lock_irqsave(&old_rb->event_lock, flags);
5341 		list_del_rcu(&event->rb_entry);
5342 		spin_unlock_irqrestore(&old_rb->event_lock, flags);
5343 
5344 		event->rcu_batches = get_state_synchronize_rcu();
5345 		event->rcu_pending = 1;
5346 	}
5347 
5348 	if (rb) {
5349 		if (event->rcu_pending) {
5350 			cond_synchronize_rcu(event->rcu_batches);
5351 			event->rcu_pending = 0;
5352 		}
5353 
5354 		spin_lock_irqsave(&rb->event_lock, flags);
5355 		list_add_rcu(&event->rb_entry, &rb->event_list);
5356 		spin_unlock_irqrestore(&rb->event_lock, flags);
5357 	}
5358 
5359 	/*
5360 	 * Avoid racing with perf_mmap_close(AUX): stop the event
5361 	 * before swizzling the event::rb pointer; if it's getting
5362 	 * unmapped, its aux_mmap_count will be 0 and it won't
5363 	 * restart. See the comment in __perf_pmu_output_stop().
5364 	 *
5365 	 * Data will inevitably be lost when set_output is done in
5366 	 * mid-air, but then again, whoever does it like this is
5367 	 * not in for the data anyway.
5368 	 */
5369 	if (has_aux(event))
5370 		perf_event_stop(event, 0);
5371 
5372 	rcu_assign_pointer(event->rb, rb);
5373 
5374 	if (old_rb) {
5375 		ring_buffer_put(old_rb);
5376 		/*
5377 		 * Since we detached before setting the new rb, so that we
5378 		 * could attach the new rb, we could have missed a wakeup.
5379 		 * Provide it now.
5380 		 */
5381 		wake_up_all(&event->waitq);
5382 	}
5383 }
5384 
5385 static void ring_buffer_wakeup(struct perf_event *event)
5386 {
5387 	struct ring_buffer *rb;
5388 
5389 	rcu_read_lock();
5390 	rb = rcu_dereference(event->rb);
5391 	if (rb) {
5392 		list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5393 			wake_up_all(&event->waitq);
5394 	}
5395 	rcu_read_unlock();
5396 }
5397 
5398 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5399 {
5400 	struct ring_buffer *rb;
5401 
5402 	rcu_read_lock();
5403 	rb = rcu_dereference(event->rb);
5404 	if (rb) {
5405 		if (!refcount_inc_not_zero(&rb->refcount))
5406 			rb = NULL;
5407 	}
5408 	rcu_read_unlock();
5409 
5410 	return rb;
5411 }
5412 
5413 void ring_buffer_put(struct ring_buffer *rb)
5414 {
5415 	if (!refcount_dec_and_test(&rb->refcount))
5416 		return;
5417 
5418 	WARN_ON_ONCE(!list_empty(&rb->event_list));
5419 
5420 	call_rcu(&rb->rcu_head, rb_free_rcu);
5421 }
5422 
5423 static void perf_mmap_open(struct vm_area_struct *vma)
5424 {
5425 	struct perf_event *event = vma->vm_file->private_data;
5426 
5427 	atomic_inc(&event->mmap_count);
5428 	atomic_inc(&event->rb->mmap_count);
5429 
5430 	if (vma->vm_pgoff)
5431 		atomic_inc(&event->rb->aux_mmap_count);
5432 
5433 	if (event->pmu->event_mapped)
5434 		event->pmu->event_mapped(event, vma->vm_mm);
5435 }
5436 
5437 static void perf_pmu_output_stop(struct perf_event *event);
5438 
5439 /*
5440  * A buffer can be mmap()ed multiple times; either directly through the same
5441  * event, or through other events by use of perf_event_set_output().
5442  *
5443  * In order to undo the VM accounting done by perf_mmap() we need to destroy
5444  * the buffer here, where we still have a VM context. This means we need
5445  * to detach all events redirecting to us.
5446  */
5447 static void perf_mmap_close(struct vm_area_struct *vma)
5448 {
5449 	struct perf_event *event = vma->vm_file->private_data;
5450 
5451 	struct ring_buffer *rb = ring_buffer_get(event);
5452 	struct user_struct *mmap_user = rb->mmap_user;
5453 	int mmap_locked = rb->mmap_locked;
5454 	unsigned long size = perf_data_size(rb);
5455 
5456 	if (event->pmu->event_unmapped)
5457 		event->pmu->event_unmapped(event, vma->vm_mm);
5458 
5459 	/*
5460 	 * rb->aux_mmap_count will always drop before rb->mmap_count and
5461 	 * event->mmap_count, so it is ok to use event->mmap_mutex to
5462 	 * serialize with perf_mmap here.
5463 	 */
5464 	if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5465 	    atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5466 		/*
5467 		 * Stop all AUX events that are writing to this buffer,
5468 		 * so that we can free its AUX pages and corresponding PMU
5469 		 * data. Note that after rb::aux_mmap_count dropped to zero,
5470 		 * they won't start any more (see perf_aux_output_begin()).
5471 		 */
5472 		perf_pmu_output_stop(event);
5473 
5474 		/* now it's safe to free the pages */
5475 		atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5476 		vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5477 
5478 		/* this has to be the last one */
5479 		rb_free_aux(rb);
5480 		WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
5481 
5482 		mutex_unlock(&event->mmap_mutex);
5483 	}
5484 
5485 	atomic_dec(&rb->mmap_count);
5486 
5487 	if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5488 		goto out_put;
5489 
5490 	ring_buffer_attach(event, NULL);
5491 	mutex_unlock(&event->mmap_mutex);
5492 
5493 	/* If there's still other mmap()s of this buffer, we're done. */
5494 	if (atomic_read(&rb->mmap_count))
5495 		goto out_put;
5496 
5497 	/*
5498 	 * No other mmap()s, detach from all other events that might redirect
5499 	 * into the now unreachable buffer. Somewhat complicated by the
5500 	 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5501 	 */
5502 again:
5503 	rcu_read_lock();
5504 	list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5505 		if (!atomic_long_inc_not_zero(&event->refcount)) {
5506 			/*
5507 			 * This event is en-route to free_event() which will
5508 			 * detach it and remove it from the list.
5509 			 */
5510 			continue;
5511 		}
5512 		rcu_read_unlock();
5513 
5514 		mutex_lock(&event->mmap_mutex);
5515 		/*
5516 		 * Check we didn't race with perf_event_set_output() which can
5517 		 * swizzle the rb from under us while we were waiting to
5518 		 * acquire mmap_mutex.
5519 		 *
5520 		 * If we find a different rb; ignore this event, a next
5521 		 * iteration will no longer find it on the list. We have to
5522 		 * still restart the iteration to make sure we're not now
5523 		 * iterating the wrong list.
5524 		 */
5525 		if (event->rb == rb)
5526 			ring_buffer_attach(event, NULL);
5527 
5528 		mutex_unlock(&event->mmap_mutex);
5529 		put_event(event);
5530 
5531 		/*
5532 		 * Restart the iteration; either we're on the wrong list or
5533 		 * destroyed its integrity by doing a deletion.
5534 		 */
5535 		goto again;
5536 	}
5537 	rcu_read_unlock();
5538 
5539 	/*
5540 	 * It could be there's still a few 0-ref events on the list; they'll
5541 	 * get cleaned up by free_event() -- they'll also still have their
5542 	 * ref on the rb and will free it whenever they are done with it.
5543 	 *
5544 	 * Aside from that, this buffer is 'fully' detached and unmapped,
5545 	 * undo the VM accounting.
5546 	 */
5547 
5548 	atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5549 	vma->vm_mm->pinned_vm -= mmap_locked;
5550 	free_uid(mmap_user);
5551 
5552 out_put:
5553 	ring_buffer_put(rb); /* could be last */
5554 }
5555 
5556 static const struct vm_operations_struct perf_mmap_vmops = {
5557 	.open		= perf_mmap_open,
5558 	.close		= perf_mmap_close, /* non mergeable */
5559 	.fault		= perf_mmap_fault,
5560 	.page_mkwrite	= perf_mmap_fault,
5561 };
5562 
5563 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5564 {
5565 	struct perf_event *event = file->private_data;
5566 	unsigned long user_locked, user_lock_limit;
5567 	struct user_struct *user = current_user();
5568 	unsigned long locked, lock_limit;
5569 	struct ring_buffer *rb = NULL;
5570 	unsigned long vma_size;
5571 	unsigned long nr_pages;
5572 	long user_extra = 0, extra = 0;
5573 	int ret = 0, flags = 0;
5574 
5575 	/*
5576 	 * Don't allow mmap() of inherited per-task counters. This would
5577 	 * create a performance issue due to all children writing to the
5578 	 * same rb.
5579 	 */
5580 	if (event->cpu == -1 && event->attr.inherit)
5581 		return -EINVAL;
5582 
5583 	if (!(vma->vm_flags & VM_SHARED))
5584 		return -EINVAL;
5585 
5586 	vma_size = vma->vm_end - vma->vm_start;
5587 
5588 	if (vma->vm_pgoff == 0) {
5589 		nr_pages = (vma_size / PAGE_SIZE) - 1;
5590 	} else {
5591 		/*
5592 		 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5593 		 * mapped, all subsequent mappings should have the same size
5594 		 * and offset. Must be above the normal perf buffer.
5595 		 */
5596 		u64 aux_offset, aux_size;
5597 
5598 		if (!event->rb)
5599 			return -EINVAL;
5600 
5601 		nr_pages = vma_size / PAGE_SIZE;
5602 
5603 		mutex_lock(&event->mmap_mutex);
5604 		ret = -EINVAL;
5605 
5606 		rb = event->rb;
5607 		if (!rb)
5608 			goto aux_unlock;
5609 
5610 		aux_offset = READ_ONCE(rb->user_page->aux_offset);
5611 		aux_size = READ_ONCE(rb->user_page->aux_size);
5612 
5613 		if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5614 			goto aux_unlock;
5615 
5616 		if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5617 			goto aux_unlock;
5618 
5619 		/* already mapped with a different offset */
5620 		if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5621 			goto aux_unlock;
5622 
5623 		if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5624 			goto aux_unlock;
5625 
5626 		/* already mapped with a different size */
5627 		if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5628 			goto aux_unlock;
5629 
5630 		if (!is_power_of_2(nr_pages))
5631 			goto aux_unlock;
5632 
5633 		if (!atomic_inc_not_zero(&rb->mmap_count))
5634 			goto aux_unlock;
5635 
5636 		if (rb_has_aux(rb)) {
5637 			atomic_inc(&rb->aux_mmap_count);
5638 			ret = 0;
5639 			goto unlock;
5640 		}
5641 
5642 		atomic_set(&rb->aux_mmap_count, 1);
5643 		user_extra = nr_pages;
5644 
5645 		goto accounting;
5646 	}
5647 
5648 	/*
5649 	 * If we have rb pages ensure they're a power-of-two number, so we
5650 	 * can do bitmasks instead of modulo.
5651 	 */
5652 	if (nr_pages != 0 && !is_power_of_2(nr_pages))
5653 		return -EINVAL;
5654 
5655 	if (vma_size != PAGE_SIZE * (1 + nr_pages))
5656 		return -EINVAL;
5657 
5658 	WARN_ON_ONCE(event->ctx->parent_ctx);
5659 again:
5660 	mutex_lock(&event->mmap_mutex);
5661 	if (event->rb) {
5662 		if (event->rb->nr_pages != nr_pages) {
5663 			ret = -EINVAL;
5664 			goto unlock;
5665 		}
5666 
5667 		if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5668 			/*
5669 			 * Raced against perf_mmap_close() through
5670 			 * perf_event_set_output(). Try again, hope for better
5671 			 * luck.
5672 			 */
5673 			mutex_unlock(&event->mmap_mutex);
5674 			goto again;
5675 		}
5676 
5677 		goto unlock;
5678 	}
5679 
5680 	user_extra = nr_pages + 1;
5681 
5682 accounting:
5683 	user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5684 
5685 	/*
5686 	 * Increase the limit linearly with more CPUs:
5687 	 */
5688 	user_lock_limit *= num_online_cpus();
5689 
5690 	user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5691 
5692 	if (user_locked > user_lock_limit)
5693 		extra = user_locked - user_lock_limit;
5694 
5695 	lock_limit = rlimit(RLIMIT_MEMLOCK);
5696 	lock_limit >>= PAGE_SHIFT;
5697 	locked = vma->vm_mm->pinned_vm + extra;
5698 
5699 	if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5700 		!capable(CAP_IPC_LOCK)) {
5701 		ret = -EPERM;
5702 		goto unlock;
5703 	}
5704 
5705 	WARN_ON(!rb && event->rb);
5706 
5707 	if (vma->vm_flags & VM_WRITE)
5708 		flags |= RING_BUFFER_WRITABLE;
5709 
5710 	if (!rb) {
5711 		rb = rb_alloc(nr_pages,
5712 			      event->attr.watermark ? event->attr.wakeup_watermark : 0,
5713 			      event->cpu, flags);
5714 
5715 		if (!rb) {
5716 			ret = -ENOMEM;
5717 			goto unlock;
5718 		}
5719 
5720 		atomic_set(&rb->mmap_count, 1);
5721 		rb->mmap_user = get_current_user();
5722 		rb->mmap_locked = extra;
5723 
5724 		ring_buffer_attach(event, rb);
5725 
5726 		perf_event_init_userpage(event);
5727 		perf_event_update_userpage(event);
5728 	} else {
5729 		ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5730 				   event->attr.aux_watermark, flags);
5731 		if (!ret)
5732 			rb->aux_mmap_locked = extra;
5733 	}
5734 
5735 unlock:
5736 	if (!ret) {
5737 		atomic_long_add(user_extra, &user->locked_vm);
5738 		vma->vm_mm->pinned_vm += extra;
5739 
5740 		atomic_inc(&event->mmap_count);
5741 	} else if (rb) {
5742 		atomic_dec(&rb->mmap_count);
5743 	}
5744 aux_unlock:
5745 	mutex_unlock(&event->mmap_mutex);
5746 
5747 	/*
5748 	 * Since pinned accounting is per vm we cannot allow fork() to copy our
5749 	 * vma.
5750 	 */
5751 	vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5752 	vma->vm_ops = &perf_mmap_vmops;
5753 
5754 	if (event->pmu->event_mapped)
5755 		event->pmu->event_mapped(event, vma->vm_mm);
5756 
5757 	return ret;
5758 }
5759 
5760 static int perf_fasync(int fd, struct file *filp, int on)
5761 {
5762 	struct inode *inode = file_inode(filp);
5763 	struct perf_event *event = filp->private_data;
5764 	int retval;
5765 
5766 	inode_lock(inode);
5767 	retval = fasync_helper(fd, filp, on, &event->fasync);
5768 	inode_unlock(inode);
5769 
5770 	if (retval < 0)
5771 		return retval;
5772 
5773 	return 0;
5774 }
5775 
5776 static const struct file_operations perf_fops = {
5777 	.llseek			= no_llseek,
5778 	.release		= perf_release,
5779 	.read			= perf_read,
5780 	.poll			= perf_poll,
5781 	.unlocked_ioctl		= perf_ioctl,
5782 	.compat_ioctl		= perf_compat_ioctl,
5783 	.mmap			= perf_mmap,
5784 	.fasync			= perf_fasync,
5785 };
5786 
5787 /*
5788  * Perf event wakeup
5789  *
5790  * If there's data, ensure we set the poll() state and publish everything
5791  * to user-space before waking everybody up.
5792  */
5793 
5794 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5795 {
5796 	/* only the parent has fasync state */
5797 	if (event->parent)
5798 		event = event->parent;
5799 	return &event->fasync;
5800 }
5801 
5802 void perf_event_wakeup(struct perf_event *event)
5803 {
5804 	ring_buffer_wakeup(event);
5805 
5806 	if (event->pending_kill) {
5807 		kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5808 		event->pending_kill = 0;
5809 	}
5810 }
5811 
5812 static void perf_pending_event(struct irq_work *entry)
5813 {
5814 	struct perf_event *event = container_of(entry,
5815 			struct perf_event, pending);
5816 	int rctx;
5817 
5818 	rctx = perf_swevent_get_recursion_context();
5819 	/*
5820 	 * If we 'fail' here, that's OK, it means recursion is already disabled
5821 	 * and we won't recurse 'further'.
5822 	 */
5823 
5824 	if (event->pending_disable) {
5825 		event->pending_disable = 0;
5826 		perf_event_disable_local(event);
5827 	}
5828 
5829 	if (event->pending_wakeup) {
5830 		event->pending_wakeup = 0;
5831 		perf_event_wakeup(event);
5832 	}
5833 
5834 	if (rctx >= 0)
5835 		perf_swevent_put_recursion_context(rctx);
5836 }
5837 
5838 /*
5839  * We assume there is only KVM supporting the callbacks.
5840  * Later on, we might change it to a list if there is
5841  * another virtualization implementation supporting the callbacks.
5842  */
5843 struct perf_guest_info_callbacks *perf_guest_cbs;
5844 
5845 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5846 {
5847 	perf_guest_cbs = cbs;
5848 	return 0;
5849 }
5850 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5851 
5852 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5853 {
5854 	perf_guest_cbs = NULL;
5855 	return 0;
5856 }
5857 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5858 
5859 static void
5860 perf_output_sample_regs(struct perf_output_handle *handle,
5861 			struct pt_regs *regs, u64 mask)
5862 {
5863 	int bit;
5864 	DECLARE_BITMAP(_mask, 64);
5865 
5866 	bitmap_from_u64(_mask, mask);
5867 	for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5868 		u64 val;
5869 
5870 		val = perf_reg_value(regs, bit);
5871 		perf_output_put(handle, val);
5872 	}
5873 }
5874 
5875 static void perf_sample_regs_user(struct perf_regs *regs_user,
5876 				  struct pt_regs *regs,
5877 				  struct pt_regs *regs_user_copy)
5878 {
5879 	if (user_mode(regs)) {
5880 		regs_user->abi = perf_reg_abi(current);
5881 		regs_user->regs = regs;
5882 	} else if (current->mm) {
5883 		perf_get_regs_user(regs_user, regs, regs_user_copy);
5884 	} else {
5885 		regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5886 		regs_user->regs = NULL;
5887 	}
5888 }
5889 
5890 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5891 				  struct pt_regs *regs)
5892 {
5893 	regs_intr->regs = regs;
5894 	regs_intr->abi  = perf_reg_abi(current);
5895 }
5896 
5897 
5898 /*
5899  * Get remaining task size from user stack pointer.
5900  *
5901  * It'd be better to take stack vma map and limit this more
5902  * precisly, but there's no way to get it safely under interrupt,
5903  * so using TASK_SIZE as limit.
5904  */
5905 static u64 perf_ustack_task_size(struct pt_regs *regs)
5906 {
5907 	unsigned long addr = perf_user_stack_pointer(regs);
5908 
5909 	if (!addr || addr >= TASK_SIZE)
5910 		return 0;
5911 
5912 	return TASK_SIZE - addr;
5913 }
5914 
5915 static u16
5916 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5917 			struct pt_regs *regs)
5918 {
5919 	u64 task_size;
5920 
5921 	/* No regs, no stack pointer, no dump. */
5922 	if (!regs)
5923 		return 0;
5924 
5925 	/*
5926 	 * Check if we fit in with the requested stack size into the:
5927 	 * - TASK_SIZE
5928 	 *   If we don't, we limit the size to the TASK_SIZE.
5929 	 *
5930 	 * - remaining sample size
5931 	 *   If we don't, we customize the stack size to
5932 	 *   fit in to the remaining sample size.
5933 	 */
5934 
5935 	task_size  = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5936 	stack_size = min(stack_size, (u16) task_size);
5937 
5938 	/* Current header size plus static size and dynamic size. */
5939 	header_size += 2 * sizeof(u64);
5940 
5941 	/* Do we fit in with the current stack dump size? */
5942 	if ((u16) (header_size + stack_size) < header_size) {
5943 		/*
5944 		 * If we overflow the maximum size for the sample,
5945 		 * we customize the stack dump size to fit in.
5946 		 */
5947 		stack_size = USHRT_MAX - header_size - sizeof(u64);
5948 		stack_size = round_up(stack_size, sizeof(u64));
5949 	}
5950 
5951 	return stack_size;
5952 }
5953 
5954 static void
5955 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5956 			  struct pt_regs *regs)
5957 {
5958 	/* Case of a kernel thread, nothing to dump */
5959 	if (!regs) {
5960 		u64 size = 0;
5961 		perf_output_put(handle, size);
5962 	} else {
5963 		unsigned long sp;
5964 		unsigned int rem;
5965 		u64 dyn_size;
5966 		mm_segment_t fs;
5967 
5968 		/*
5969 		 * We dump:
5970 		 * static size
5971 		 *   - the size requested by user or the best one we can fit
5972 		 *     in to the sample max size
5973 		 * data
5974 		 *   - user stack dump data
5975 		 * dynamic size
5976 		 *   - the actual dumped size
5977 		 */
5978 
5979 		/* Static size. */
5980 		perf_output_put(handle, dump_size);
5981 
5982 		/* Data. */
5983 		sp = perf_user_stack_pointer(regs);
5984 		fs = get_fs();
5985 		set_fs(USER_DS);
5986 		rem = __output_copy_user(handle, (void *) sp, dump_size);
5987 		set_fs(fs);
5988 		dyn_size = dump_size - rem;
5989 
5990 		perf_output_skip(handle, rem);
5991 
5992 		/* Dynamic size. */
5993 		perf_output_put(handle, dyn_size);
5994 	}
5995 }
5996 
5997 static void __perf_event_header__init_id(struct perf_event_header *header,
5998 					 struct perf_sample_data *data,
5999 					 struct perf_event *event)
6000 {
6001 	u64 sample_type = event->attr.sample_type;
6002 
6003 	data->type = sample_type;
6004 	header->size += event->id_header_size;
6005 
6006 	if (sample_type & PERF_SAMPLE_TID) {
6007 		/* namespace issues */
6008 		data->tid_entry.pid = perf_event_pid(event, current);
6009 		data->tid_entry.tid = perf_event_tid(event, current);
6010 	}
6011 
6012 	if (sample_type & PERF_SAMPLE_TIME)
6013 		data->time = perf_event_clock(event);
6014 
6015 	if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6016 		data->id = primary_event_id(event);
6017 
6018 	if (sample_type & PERF_SAMPLE_STREAM_ID)
6019 		data->stream_id = event->id;
6020 
6021 	if (sample_type & PERF_SAMPLE_CPU) {
6022 		data->cpu_entry.cpu	 = raw_smp_processor_id();
6023 		data->cpu_entry.reserved = 0;
6024 	}
6025 }
6026 
6027 void perf_event_header__init_id(struct perf_event_header *header,
6028 				struct perf_sample_data *data,
6029 				struct perf_event *event)
6030 {
6031 	if (event->attr.sample_id_all)
6032 		__perf_event_header__init_id(header, data, event);
6033 }
6034 
6035 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6036 					   struct perf_sample_data *data)
6037 {
6038 	u64 sample_type = data->type;
6039 
6040 	if (sample_type & PERF_SAMPLE_TID)
6041 		perf_output_put(handle, data->tid_entry);
6042 
6043 	if (sample_type & PERF_SAMPLE_TIME)
6044 		perf_output_put(handle, data->time);
6045 
6046 	if (sample_type & PERF_SAMPLE_ID)
6047 		perf_output_put(handle, data->id);
6048 
6049 	if (sample_type & PERF_SAMPLE_STREAM_ID)
6050 		perf_output_put(handle, data->stream_id);
6051 
6052 	if (sample_type & PERF_SAMPLE_CPU)
6053 		perf_output_put(handle, data->cpu_entry);
6054 
6055 	if (sample_type & PERF_SAMPLE_IDENTIFIER)
6056 		perf_output_put(handle, data->id);
6057 }
6058 
6059 void perf_event__output_id_sample(struct perf_event *event,
6060 				  struct perf_output_handle *handle,
6061 				  struct perf_sample_data *sample)
6062 {
6063 	if (event->attr.sample_id_all)
6064 		__perf_event__output_id_sample(handle, sample);
6065 }
6066 
6067 static void perf_output_read_one(struct perf_output_handle *handle,
6068 				 struct perf_event *event,
6069 				 u64 enabled, u64 running)
6070 {
6071 	u64 read_format = event->attr.read_format;
6072 	u64 values[4];
6073 	int n = 0;
6074 
6075 	values[n++] = perf_event_count(event);
6076 	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6077 		values[n++] = enabled +
6078 			atomic64_read(&event->child_total_time_enabled);
6079 	}
6080 	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6081 		values[n++] = running +
6082 			atomic64_read(&event->child_total_time_running);
6083 	}
6084 	if (read_format & PERF_FORMAT_ID)
6085 		values[n++] = primary_event_id(event);
6086 
6087 	__output_copy(handle, values, n * sizeof(u64));
6088 }
6089 
6090 static void perf_output_read_group(struct perf_output_handle *handle,
6091 			    struct perf_event *event,
6092 			    u64 enabled, u64 running)
6093 {
6094 	struct perf_event *leader = event->group_leader, *sub;
6095 	u64 read_format = event->attr.read_format;
6096 	u64 values[5];
6097 	int n = 0;
6098 
6099 	values[n++] = 1 + leader->nr_siblings;
6100 
6101 	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6102 		values[n++] = enabled;
6103 
6104 	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6105 		values[n++] = running;
6106 
6107 	if ((leader != event) &&
6108 	    (leader->state == PERF_EVENT_STATE_ACTIVE))
6109 		leader->pmu->read(leader);
6110 
6111 	values[n++] = perf_event_count(leader);
6112 	if (read_format & PERF_FORMAT_ID)
6113 		values[n++] = primary_event_id(leader);
6114 
6115 	__output_copy(handle, values, n * sizeof(u64));
6116 
6117 	for_each_sibling_event(sub, leader) {
6118 		n = 0;
6119 
6120 		if ((sub != event) &&
6121 		    (sub->state == PERF_EVENT_STATE_ACTIVE))
6122 			sub->pmu->read(sub);
6123 
6124 		values[n++] = perf_event_count(sub);
6125 		if (read_format & PERF_FORMAT_ID)
6126 			values[n++] = primary_event_id(sub);
6127 
6128 		__output_copy(handle, values, n * sizeof(u64));
6129 	}
6130 }
6131 
6132 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6133 				 PERF_FORMAT_TOTAL_TIME_RUNNING)
6134 
6135 /*
6136  * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6137  *
6138  * The problem is that its both hard and excessively expensive to iterate the
6139  * child list, not to mention that its impossible to IPI the children running
6140  * on another CPU, from interrupt/NMI context.
6141  */
6142 static void perf_output_read(struct perf_output_handle *handle,
6143 			     struct perf_event *event)
6144 {
6145 	u64 enabled = 0, running = 0, now;
6146 	u64 read_format = event->attr.read_format;
6147 
6148 	/*
6149 	 * compute total_time_enabled, total_time_running
6150 	 * based on snapshot values taken when the event
6151 	 * was last scheduled in.
6152 	 *
6153 	 * we cannot simply called update_context_time()
6154 	 * because of locking issue as we are called in
6155 	 * NMI context
6156 	 */
6157 	if (read_format & PERF_FORMAT_TOTAL_TIMES)
6158 		calc_timer_values(event, &now, &enabled, &running);
6159 
6160 	if (event->attr.read_format & PERF_FORMAT_GROUP)
6161 		perf_output_read_group(handle, event, enabled, running);
6162 	else
6163 		perf_output_read_one(handle, event, enabled, running);
6164 }
6165 
6166 void perf_output_sample(struct perf_output_handle *handle,
6167 			struct perf_event_header *header,
6168 			struct perf_sample_data *data,
6169 			struct perf_event *event)
6170 {
6171 	u64 sample_type = data->type;
6172 
6173 	perf_output_put(handle, *header);
6174 
6175 	if (sample_type & PERF_SAMPLE_IDENTIFIER)
6176 		perf_output_put(handle, data->id);
6177 
6178 	if (sample_type & PERF_SAMPLE_IP)
6179 		perf_output_put(handle, data->ip);
6180 
6181 	if (sample_type & PERF_SAMPLE_TID)
6182 		perf_output_put(handle, data->tid_entry);
6183 
6184 	if (sample_type & PERF_SAMPLE_TIME)
6185 		perf_output_put(handle, data->time);
6186 
6187 	if (sample_type & PERF_SAMPLE_ADDR)
6188 		perf_output_put(handle, data->addr);
6189 
6190 	if (sample_type & PERF_SAMPLE_ID)
6191 		perf_output_put(handle, data->id);
6192 
6193 	if (sample_type & PERF_SAMPLE_STREAM_ID)
6194 		perf_output_put(handle, data->stream_id);
6195 
6196 	if (sample_type & PERF_SAMPLE_CPU)
6197 		perf_output_put(handle, data->cpu_entry);
6198 
6199 	if (sample_type & PERF_SAMPLE_PERIOD)
6200 		perf_output_put(handle, data->period);
6201 
6202 	if (sample_type & PERF_SAMPLE_READ)
6203 		perf_output_read(handle, event);
6204 
6205 	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6206 		int size = 1;
6207 
6208 		size += data->callchain->nr;
6209 		size *= sizeof(u64);
6210 		__output_copy(handle, data->callchain, size);
6211 	}
6212 
6213 	if (sample_type & PERF_SAMPLE_RAW) {
6214 		struct perf_raw_record *raw = data->raw;
6215 
6216 		if (raw) {
6217 			struct perf_raw_frag *frag = &raw->frag;
6218 
6219 			perf_output_put(handle, raw->size);
6220 			do {
6221 				if (frag->copy) {
6222 					__output_custom(handle, frag->copy,
6223 							frag->data, frag->size);
6224 				} else {
6225 					__output_copy(handle, frag->data,
6226 						      frag->size);
6227 				}
6228 				if (perf_raw_frag_last(frag))
6229 					break;
6230 				frag = frag->next;
6231 			} while (1);
6232 			if (frag->pad)
6233 				__output_skip(handle, NULL, frag->pad);
6234 		} else {
6235 			struct {
6236 				u32	size;
6237 				u32	data;
6238 			} raw = {
6239 				.size = sizeof(u32),
6240 				.data = 0,
6241 			};
6242 			perf_output_put(handle, raw);
6243 		}
6244 	}
6245 
6246 	if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6247 		if (data->br_stack) {
6248 			size_t size;
6249 
6250 			size = data->br_stack->nr
6251 			     * sizeof(struct perf_branch_entry);
6252 
6253 			perf_output_put(handle, data->br_stack->nr);
6254 			perf_output_copy(handle, data->br_stack->entries, size);
6255 		} else {
6256 			/*
6257 			 * we always store at least the value of nr
6258 			 */
6259 			u64 nr = 0;
6260 			perf_output_put(handle, nr);
6261 		}
6262 	}
6263 
6264 	if (sample_type & PERF_SAMPLE_REGS_USER) {
6265 		u64 abi = data->regs_user.abi;
6266 
6267 		/*
6268 		 * If there are no regs to dump, notice it through
6269 		 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6270 		 */
6271 		perf_output_put(handle, abi);
6272 
6273 		if (abi) {
6274 			u64 mask = event->attr.sample_regs_user;
6275 			perf_output_sample_regs(handle,
6276 						data->regs_user.regs,
6277 						mask);
6278 		}
6279 	}
6280 
6281 	if (sample_type & PERF_SAMPLE_STACK_USER) {
6282 		perf_output_sample_ustack(handle,
6283 					  data->stack_user_size,
6284 					  data->regs_user.regs);
6285 	}
6286 
6287 	if (sample_type & PERF_SAMPLE_WEIGHT)
6288 		perf_output_put(handle, data->weight);
6289 
6290 	if (sample_type & PERF_SAMPLE_DATA_SRC)
6291 		perf_output_put(handle, data->data_src.val);
6292 
6293 	if (sample_type & PERF_SAMPLE_TRANSACTION)
6294 		perf_output_put(handle, data->txn);
6295 
6296 	if (sample_type & PERF_SAMPLE_REGS_INTR) {
6297 		u64 abi = data->regs_intr.abi;
6298 		/*
6299 		 * If there are no regs to dump, notice it through
6300 		 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6301 		 */
6302 		perf_output_put(handle, abi);
6303 
6304 		if (abi) {
6305 			u64 mask = event->attr.sample_regs_intr;
6306 
6307 			perf_output_sample_regs(handle,
6308 						data->regs_intr.regs,
6309 						mask);
6310 		}
6311 	}
6312 
6313 	if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6314 		perf_output_put(handle, data->phys_addr);
6315 
6316 	if (!event->attr.watermark) {
6317 		int wakeup_events = event->attr.wakeup_events;
6318 
6319 		if (wakeup_events) {
6320 			struct ring_buffer *rb = handle->rb;
6321 			int events = local_inc_return(&rb->events);
6322 
6323 			if (events >= wakeup_events) {
6324 				local_sub(wakeup_events, &rb->events);
6325 				local_inc(&rb->wakeup);
6326 			}
6327 		}
6328 	}
6329 }
6330 
6331 static u64 perf_virt_to_phys(u64 virt)
6332 {
6333 	u64 phys_addr = 0;
6334 	struct page *p = NULL;
6335 
6336 	if (!virt)
6337 		return 0;
6338 
6339 	if (virt >= TASK_SIZE) {
6340 		/* If it's vmalloc()d memory, leave phys_addr as 0 */
6341 		if (virt_addr_valid((void *)(uintptr_t)virt) &&
6342 		    !(virt >= VMALLOC_START && virt < VMALLOC_END))
6343 			phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6344 	} else {
6345 		/*
6346 		 * Walking the pages tables for user address.
6347 		 * Interrupts are disabled, so it prevents any tear down
6348 		 * of the page tables.
6349 		 * Try IRQ-safe __get_user_pages_fast first.
6350 		 * If failed, leave phys_addr as 0.
6351 		 */
6352 		if ((current->mm != NULL) &&
6353 		    (__get_user_pages_fast(virt, 1, 0, &p) == 1))
6354 			phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6355 
6356 		if (p)
6357 			put_page(p);
6358 	}
6359 
6360 	return phys_addr;
6361 }
6362 
6363 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
6364 
6365 struct perf_callchain_entry *
6366 perf_callchain(struct perf_event *event, struct pt_regs *regs)
6367 {
6368 	bool kernel = !event->attr.exclude_callchain_kernel;
6369 	bool user   = !event->attr.exclude_callchain_user;
6370 	/* Disallow cross-task user callchains. */
6371 	bool crosstask = event->ctx->task && event->ctx->task != current;
6372 	const u32 max_stack = event->attr.sample_max_stack;
6373 	struct perf_callchain_entry *callchain;
6374 
6375 	if (!kernel && !user)
6376 		return &__empty_callchain;
6377 
6378 	callchain = get_perf_callchain(regs, 0, kernel, user,
6379 				       max_stack, crosstask, true);
6380 	return callchain ?: &__empty_callchain;
6381 }
6382 
6383 void perf_prepare_sample(struct perf_event_header *header,
6384 			 struct perf_sample_data *data,
6385 			 struct perf_event *event,
6386 			 struct pt_regs *regs)
6387 {
6388 	u64 sample_type = event->attr.sample_type;
6389 
6390 	header->type = PERF_RECORD_SAMPLE;
6391 	header->size = sizeof(*header) + event->header_size;
6392 
6393 	header->misc = 0;
6394 	header->misc |= perf_misc_flags(regs);
6395 
6396 	__perf_event_header__init_id(header, data, event);
6397 
6398 	if (sample_type & PERF_SAMPLE_IP)
6399 		data->ip = perf_instruction_pointer(regs);
6400 
6401 	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6402 		int size = 1;
6403 
6404 		if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
6405 			data->callchain = perf_callchain(event, regs);
6406 
6407 		size += data->callchain->nr;
6408 
6409 		header->size += size * sizeof(u64);
6410 	}
6411 
6412 	if (sample_type & PERF_SAMPLE_RAW) {
6413 		struct perf_raw_record *raw = data->raw;
6414 		int size;
6415 
6416 		if (raw) {
6417 			struct perf_raw_frag *frag = &raw->frag;
6418 			u32 sum = 0;
6419 
6420 			do {
6421 				sum += frag->size;
6422 				if (perf_raw_frag_last(frag))
6423 					break;
6424 				frag = frag->next;
6425 			} while (1);
6426 
6427 			size = round_up(sum + sizeof(u32), sizeof(u64));
6428 			raw->size = size - sizeof(u32);
6429 			frag->pad = raw->size - sum;
6430 		} else {
6431 			size = sizeof(u64);
6432 		}
6433 
6434 		header->size += size;
6435 	}
6436 
6437 	if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6438 		int size = sizeof(u64); /* nr */
6439 		if (data->br_stack) {
6440 			size += data->br_stack->nr
6441 			      * sizeof(struct perf_branch_entry);
6442 		}
6443 		header->size += size;
6444 	}
6445 
6446 	if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6447 		perf_sample_regs_user(&data->regs_user, regs,
6448 				      &data->regs_user_copy);
6449 
6450 	if (sample_type & PERF_SAMPLE_REGS_USER) {
6451 		/* regs dump ABI info */
6452 		int size = sizeof(u64);
6453 
6454 		if (data->regs_user.regs) {
6455 			u64 mask = event->attr.sample_regs_user;
6456 			size += hweight64(mask) * sizeof(u64);
6457 		}
6458 
6459 		header->size += size;
6460 	}
6461 
6462 	if (sample_type & PERF_SAMPLE_STACK_USER) {
6463 		/*
6464 		 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6465 		 * processed as the last one or have additional check added
6466 		 * in case new sample type is added, because we could eat
6467 		 * up the rest of the sample size.
6468 		 */
6469 		u16 stack_size = event->attr.sample_stack_user;
6470 		u16 size = sizeof(u64);
6471 
6472 		stack_size = perf_sample_ustack_size(stack_size, header->size,
6473 						     data->regs_user.regs);
6474 
6475 		/*
6476 		 * If there is something to dump, add space for the dump
6477 		 * itself and for the field that tells the dynamic size,
6478 		 * which is how many have been actually dumped.
6479 		 */
6480 		if (stack_size)
6481 			size += sizeof(u64) + stack_size;
6482 
6483 		data->stack_user_size = stack_size;
6484 		header->size += size;
6485 	}
6486 
6487 	if (sample_type & PERF_SAMPLE_REGS_INTR) {
6488 		/* regs dump ABI info */
6489 		int size = sizeof(u64);
6490 
6491 		perf_sample_regs_intr(&data->regs_intr, regs);
6492 
6493 		if (data->regs_intr.regs) {
6494 			u64 mask = event->attr.sample_regs_intr;
6495 
6496 			size += hweight64(mask) * sizeof(u64);
6497 		}
6498 
6499 		header->size += size;
6500 	}
6501 
6502 	if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6503 		data->phys_addr = perf_virt_to_phys(data->addr);
6504 }
6505 
6506 static __always_inline int
6507 __perf_event_output(struct perf_event *event,
6508 		    struct perf_sample_data *data,
6509 		    struct pt_regs *regs,
6510 		    int (*output_begin)(struct perf_output_handle *,
6511 					struct perf_event *,
6512 					unsigned int))
6513 {
6514 	struct perf_output_handle handle;
6515 	struct perf_event_header header;
6516 	int err;
6517 
6518 	/* protect the callchain buffers */
6519 	rcu_read_lock();
6520 
6521 	perf_prepare_sample(&header, data, event, regs);
6522 
6523 	err = output_begin(&handle, event, header.size);
6524 	if (err)
6525 		goto exit;
6526 
6527 	perf_output_sample(&handle, &header, data, event);
6528 
6529 	perf_output_end(&handle);
6530 
6531 exit:
6532 	rcu_read_unlock();
6533 	return err;
6534 }
6535 
6536 void
6537 perf_event_output_forward(struct perf_event *event,
6538 			 struct perf_sample_data *data,
6539 			 struct pt_regs *regs)
6540 {
6541 	__perf_event_output(event, data, regs, perf_output_begin_forward);
6542 }
6543 
6544 void
6545 perf_event_output_backward(struct perf_event *event,
6546 			   struct perf_sample_data *data,
6547 			   struct pt_regs *regs)
6548 {
6549 	__perf_event_output(event, data, regs, perf_output_begin_backward);
6550 }
6551 
6552 int
6553 perf_event_output(struct perf_event *event,
6554 		  struct perf_sample_data *data,
6555 		  struct pt_regs *regs)
6556 {
6557 	return __perf_event_output(event, data, regs, perf_output_begin);
6558 }
6559 
6560 /*
6561  * read event_id
6562  */
6563 
6564 struct perf_read_event {
6565 	struct perf_event_header	header;
6566 
6567 	u32				pid;
6568 	u32				tid;
6569 };
6570 
6571 static void
6572 perf_event_read_event(struct perf_event *event,
6573 			struct task_struct *task)
6574 {
6575 	struct perf_output_handle handle;
6576 	struct perf_sample_data sample;
6577 	struct perf_read_event read_event = {
6578 		.header = {
6579 			.type = PERF_RECORD_READ,
6580 			.misc = 0,
6581 			.size = sizeof(read_event) + event->read_size,
6582 		},
6583 		.pid = perf_event_pid(event, task),
6584 		.tid = perf_event_tid(event, task),
6585 	};
6586 	int ret;
6587 
6588 	perf_event_header__init_id(&read_event.header, &sample, event);
6589 	ret = perf_output_begin(&handle, event, read_event.header.size);
6590 	if (ret)
6591 		return;
6592 
6593 	perf_output_put(&handle, read_event);
6594 	perf_output_read(&handle, event);
6595 	perf_event__output_id_sample(event, &handle, &sample);
6596 
6597 	perf_output_end(&handle);
6598 }
6599 
6600 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6601 
6602 static void
6603 perf_iterate_ctx(struct perf_event_context *ctx,
6604 		   perf_iterate_f output,
6605 		   void *data, bool all)
6606 {
6607 	struct perf_event *event;
6608 
6609 	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6610 		if (!all) {
6611 			if (event->state < PERF_EVENT_STATE_INACTIVE)
6612 				continue;
6613 			if (!event_filter_match(event))
6614 				continue;
6615 		}
6616 
6617 		output(event, data);
6618 	}
6619 }
6620 
6621 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6622 {
6623 	struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6624 	struct perf_event *event;
6625 
6626 	list_for_each_entry_rcu(event, &pel->list, sb_list) {
6627 		/*
6628 		 * Skip events that are not fully formed yet; ensure that
6629 		 * if we observe event->ctx, both event and ctx will be
6630 		 * complete enough. See perf_install_in_context().
6631 		 */
6632 		if (!smp_load_acquire(&event->ctx))
6633 			continue;
6634 
6635 		if (event->state < PERF_EVENT_STATE_INACTIVE)
6636 			continue;
6637 		if (!event_filter_match(event))
6638 			continue;
6639 		output(event, data);
6640 	}
6641 }
6642 
6643 /*
6644  * Iterate all events that need to receive side-band events.
6645  *
6646  * For new callers; ensure that account_pmu_sb_event() includes
6647  * your event, otherwise it might not get delivered.
6648  */
6649 static void
6650 perf_iterate_sb(perf_iterate_f output, void *data,
6651 	       struct perf_event_context *task_ctx)
6652 {
6653 	struct perf_event_context *ctx;
6654 	int ctxn;
6655 
6656 	rcu_read_lock();
6657 	preempt_disable();
6658 
6659 	/*
6660 	 * If we have task_ctx != NULL we only notify the task context itself.
6661 	 * The task_ctx is set only for EXIT events before releasing task
6662 	 * context.
6663 	 */
6664 	if (task_ctx) {
6665 		perf_iterate_ctx(task_ctx, output, data, false);
6666 		goto done;
6667 	}
6668 
6669 	perf_iterate_sb_cpu(output, data);
6670 
6671 	for_each_task_context_nr(ctxn) {
6672 		ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6673 		if (ctx)
6674 			perf_iterate_ctx(ctx, output, data, false);
6675 	}
6676 done:
6677 	preempt_enable();
6678 	rcu_read_unlock();
6679 }
6680 
6681 /*
6682  * Clear all file-based filters at exec, they'll have to be
6683  * re-instated when/if these objects are mmapped again.
6684  */
6685 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6686 {
6687 	struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6688 	struct perf_addr_filter *filter;
6689 	unsigned int restart = 0, count = 0;
6690 	unsigned long flags;
6691 
6692 	if (!has_addr_filter(event))
6693 		return;
6694 
6695 	raw_spin_lock_irqsave(&ifh->lock, flags);
6696 	list_for_each_entry(filter, &ifh->list, entry) {
6697 		if (filter->path.dentry) {
6698 			event->addr_filter_ranges[count].start = 0;
6699 			event->addr_filter_ranges[count].size = 0;
6700 			restart++;
6701 		}
6702 
6703 		count++;
6704 	}
6705 
6706 	if (restart)
6707 		event->addr_filters_gen++;
6708 	raw_spin_unlock_irqrestore(&ifh->lock, flags);
6709 
6710 	if (restart)
6711 		perf_event_stop(event, 1);
6712 }
6713 
6714 void perf_event_exec(void)
6715 {
6716 	struct perf_event_context *ctx;
6717 	int ctxn;
6718 
6719 	rcu_read_lock();
6720 	for_each_task_context_nr(ctxn) {
6721 		ctx = current->perf_event_ctxp[ctxn];
6722 		if (!ctx)
6723 			continue;
6724 
6725 		perf_event_enable_on_exec(ctxn);
6726 
6727 		perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6728 				   true);
6729 	}
6730 	rcu_read_unlock();
6731 }
6732 
6733 struct remote_output {
6734 	struct ring_buffer	*rb;
6735 	int			err;
6736 };
6737 
6738 static void __perf_event_output_stop(struct perf_event *event, void *data)
6739 {
6740 	struct perf_event *parent = event->parent;
6741 	struct remote_output *ro = data;
6742 	struct ring_buffer *rb = ro->rb;
6743 	struct stop_event_data sd = {
6744 		.event	= event,
6745 	};
6746 
6747 	if (!has_aux(event))
6748 		return;
6749 
6750 	if (!parent)
6751 		parent = event;
6752 
6753 	/*
6754 	 * In case of inheritance, it will be the parent that links to the
6755 	 * ring-buffer, but it will be the child that's actually using it.
6756 	 *
6757 	 * We are using event::rb to determine if the event should be stopped,
6758 	 * however this may race with ring_buffer_attach() (through set_output),
6759 	 * which will make us skip the event that actually needs to be stopped.
6760 	 * So ring_buffer_attach() has to stop an aux event before re-assigning
6761 	 * its rb pointer.
6762 	 */
6763 	if (rcu_dereference(parent->rb) == rb)
6764 		ro->err = __perf_event_stop(&sd);
6765 }
6766 
6767 static int __perf_pmu_output_stop(void *info)
6768 {
6769 	struct perf_event *event = info;
6770 	struct pmu *pmu = event->pmu;
6771 	struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6772 	struct remote_output ro = {
6773 		.rb	= event->rb,
6774 	};
6775 
6776 	rcu_read_lock();
6777 	perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6778 	if (cpuctx->task_ctx)
6779 		perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6780 				   &ro, false);
6781 	rcu_read_unlock();
6782 
6783 	return ro.err;
6784 }
6785 
6786 static void perf_pmu_output_stop(struct perf_event *event)
6787 {
6788 	struct perf_event *iter;
6789 	int err, cpu;
6790 
6791 restart:
6792 	rcu_read_lock();
6793 	list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6794 		/*
6795 		 * For per-CPU events, we need to make sure that neither they
6796 		 * nor their children are running; for cpu==-1 events it's
6797 		 * sufficient to stop the event itself if it's active, since
6798 		 * it can't have children.
6799 		 */
6800 		cpu = iter->cpu;
6801 		if (cpu == -1)
6802 			cpu = READ_ONCE(iter->oncpu);
6803 
6804 		if (cpu == -1)
6805 			continue;
6806 
6807 		err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6808 		if (err == -EAGAIN) {
6809 			rcu_read_unlock();
6810 			goto restart;
6811 		}
6812 	}
6813 	rcu_read_unlock();
6814 }
6815 
6816 /*
6817  * task tracking -- fork/exit
6818  *
6819  * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6820  */
6821 
6822 struct perf_task_event {
6823 	struct task_struct		*task;
6824 	struct perf_event_context	*task_ctx;
6825 
6826 	struct {
6827 		struct perf_event_header	header;
6828 
6829 		u32				pid;
6830 		u32				ppid;
6831 		u32				tid;
6832 		u32				ptid;
6833 		u64				time;
6834 	} event_id;
6835 };
6836 
6837 static int perf_event_task_match(struct perf_event *event)
6838 {
6839 	return event->attr.comm  || event->attr.mmap ||
6840 	       event->attr.mmap2 || event->attr.mmap_data ||
6841 	       event->attr.task;
6842 }
6843 
6844 static void perf_event_task_output(struct perf_event *event,
6845 				   void *data)
6846 {
6847 	struct perf_task_event *task_event = data;
6848 	struct perf_output_handle handle;
6849 	struct perf_sample_data	sample;
6850 	struct task_struct *task = task_event->task;
6851 	int ret, size = task_event->event_id.header.size;
6852 
6853 	if (!perf_event_task_match(event))
6854 		return;
6855 
6856 	perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6857 
6858 	ret = perf_output_begin(&handle, event,
6859 				task_event->event_id.header.size);
6860 	if (ret)
6861 		goto out;
6862 
6863 	task_event->event_id.pid = perf_event_pid(event, task);
6864 	task_event->event_id.ppid = perf_event_pid(event, current);
6865 
6866 	task_event->event_id.tid = perf_event_tid(event, task);
6867 	task_event->event_id.ptid = perf_event_tid(event, current);
6868 
6869 	task_event->event_id.time = perf_event_clock(event);
6870 
6871 	perf_output_put(&handle, task_event->event_id);
6872 
6873 	perf_event__output_id_sample(event, &handle, &sample);
6874 
6875 	perf_output_end(&handle);
6876 out:
6877 	task_event->event_id.header.size = size;
6878 }
6879 
6880 static void perf_event_task(struct task_struct *task,
6881 			      struct perf_event_context *task_ctx,
6882 			      int new)
6883 {
6884 	struct perf_task_event task_event;
6885 
6886 	if (!atomic_read(&nr_comm_events) &&
6887 	    !atomic_read(&nr_mmap_events) &&
6888 	    !atomic_read(&nr_task_events))
6889 		return;
6890 
6891 	task_event = (struct perf_task_event){
6892 		.task	  = task,
6893 		.task_ctx = task_ctx,
6894 		.event_id    = {
6895 			.header = {
6896 				.type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6897 				.misc = 0,
6898 				.size = sizeof(task_event.event_id),
6899 			},
6900 			/* .pid  */
6901 			/* .ppid */
6902 			/* .tid  */
6903 			/* .ptid */
6904 			/* .time */
6905 		},
6906 	};
6907 
6908 	perf_iterate_sb(perf_event_task_output,
6909 		       &task_event,
6910 		       task_ctx);
6911 }
6912 
6913 void perf_event_fork(struct task_struct *task)
6914 {
6915 	perf_event_task(task, NULL, 1);
6916 	perf_event_namespaces(task);
6917 }
6918 
6919 /*
6920  * comm tracking
6921  */
6922 
6923 struct perf_comm_event {
6924 	struct task_struct	*task;
6925 	char			*comm;
6926 	int			comm_size;
6927 
6928 	struct {
6929 		struct perf_event_header	header;
6930 
6931 		u32				pid;
6932 		u32				tid;
6933 	} event_id;
6934 };
6935 
6936 static int perf_event_comm_match(struct perf_event *event)
6937 {
6938 	return event->attr.comm;
6939 }
6940 
6941 static void perf_event_comm_output(struct perf_event *event,
6942 				   void *data)
6943 {
6944 	struct perf_comm_event *comm_event = data;
6945 	struct perf_output_handle handle;
6946 	struct perf_sample_data sample;
6947 	int size = comm_event->event_id.header.size;
6948 	int ret;
6949 
6950 	if (!perf_event_comm_match(event))
6951 		return;
6952 
6953 	perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6954 	ret = perf_output_begin(&handle, event,
6955 				comm_event->event_id.header.size);
6956 
6957 	if (ret)
6958 		goto out;
6959 
6960 	comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6961 	comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6962 
6963 	perf_output_put(&handle, comm_event->event_id);
6964 	__output_copy(&handle, comm_event->comm,
6965 				   comm_event->comm_size);
6966 
6967 	perf_event__output_id_sample(event, &handle, &sample);
6968 
6969 	perf_output_end(&handle);
6970 out:
6971 	comm_event->event_id.header.size = size;
6972 }
6973 
6974 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6975 {
6976 	char comm[TASK_COMM_LEN];
6977 	unsigned int size;
6978 
6979 	memset(comm, 0, sizeof(comm));
6980 	strlcpy(comm, comm_event->task->comm, sizeof(comm));
6981 	size = ALIGN(strlen(comm)+1, sizeof(u64));
6982 
6983 	comm_event->comm = comm;
6984 	comm_event->comm_size = size;
6985 
6986 	comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6987 
6988 	perf_iterate_sb(perf_event_comm_output,
6989 		       comm_event,
6990 		       NULL);
6991 }
6992 
6993 void perf_event_comm(struct task_struct *task, bool exec)
6994 {
6995 	struct perf_comm_event comm_event;
6996 
6997 	if (!atomic_read(&nr_comm_events))
6998 		return;
6999 
7000 	comm_event = (struct perf_comm_event){
7001 		.task	= task,
7002 		/* .comm      */
7003 		/* .comm_size */
7004 		.event_id  = {
7005 			.header = {
7006 				.type = PERF_RECORD_COMM,
7007 				.misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7008 				/* .size */
7009 			},
7010 			/* .pid */
7011 			/* .tid */
7012 		},
7013 	};
7014 
7015 	perf_event_comm_event(&comm_event);
7016 }
7017 
7018 /*
7019  * namespaces tracking
7020  */
7021 
7022 struct perf_namespaces_event {
7023 	struct task_struct		*task;
7024 
7025 	struct {
7026 		struct perf_event_header	header;
7027 
7028 		u32				pid;
7029 		u32				tid;
7030 		u64				nr_namespaces;
7031 		struct perf_ns_link_info	link_info[NR_NAMESPACES];
7032 	} event_id;
7033 };
7034 
7035 static int perf_event_namespaces_match(struct perf_event *event)
7036 {
7037 	return event->attr.namespaces;
7038 }
7039 
7040 static void perf_event_namespaces_output(struct perf_event *event,
7041 					 void *data)
7042 {
7043 	struct perf_namespaces_event *namespaces_event = data;
7044 	struct perf_output_handle handle;
7045 	struct perf_sample_data sample;
7046 	u16 header_size = namespaces_event->event_id.header.size;
7047 	int ret;
7048 
7049 	if (!perf_event_namespaces_match(event))
7050 		return;
7051 
7052 	perf_event_header__init_id(&namespaces_event->event_id.header,
7053 				   &sample, event);
7054 	ret = perf_output_begin(&handle, event,
7055 				namespaces_event->event_id.header.size);
7056 	if (ret)
7057 		goto out;
7058 
7059 	namespaces_event->event_id.pid = perf_event_pid(event,
7060 							namespaces_event->task);
7061 	namespaces_event->event_id.tid = perf_event_tid(event,
7062 							namespaces_event->task);
7063 
7064 	perf_output_put(&handle, namespaces_event->event_id);
7065 
7066 	perf_event__output_id_sample(event, &handle, &sample);
7067 
7068 	perf_output_end(&handle);
7069 out:
7070 	namespaces_event->event_id.header.size = header_size;
7071 }
7072 
7073 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7074 				   struct task_struct *task,
7075 				   const struct proc_ns_operations *ns_ops)
7076 {
7077 	struct path ns_path;
7078 	struct inode *ns_inode;
7079 	void *error;
7080 
7081 	error = ns_get_path(&ns_path, task, ns_ops);
7082 	if (!error) {
7083 		ns_inode = ns_path.dentry->d_inode;
7084 		ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7085 		ns_link_info->ino = ns_inode->i_ino;
7086 		path_put(&ns_path);
7087 	}
7088 }
7089 
7090 void perf_event_namespaces(struct task_struct *task)
7091 {
7092 	struct perf_namespaces_event namespaces_event;
7093 	struct perf_ns_link_info *ns_link_info;
7094 
7095 	if (!atomic_read(&nr_namespaces_events))
7096 		return;
7097 
7098 	namespaces_event = (struct perf_namespaces_event){
7099 		.task	= task,
7100 		.event_id  = {
7101 			.header = {
7102 				.type = PERF_RECORD_NAMESPACES,
7103 				.misc = 0,
7104 				.size = sizeof(namespaces_event.event_id),
7105 			},
7106 			/* .pid */
7107 			/* .tid */
7108 			.nr_namespaces = NR_NAMESPACES,
7109 			/* .link_info[NR_NAMESPACES] */
7110 		},
7111 	};
7112 
7113 	ns_link_info = namespaces_event.event_id.link_info;
7114 
7115 	perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7116 			       task, &mntns_operations);
7117 
7118 #ifdef CONFIG_USER_NS
7119 	perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7120 			       task, &userns_operations);
7121 #endif
7122 #ifdef CONFIG_NET_NS
7123 	perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7124 			       task, &netns_operations);
7125 #endif
7126 #ifdef CONFIG_UTS_NS
7127 	perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7128 			       task, &utsns_operations);
7129 #endif
7130 #ifdef CONFIG_IPC_NS
7131 	perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7132 			       task, &ipcns_operations);
7133 #endif
7134 #ifdef CONFIG_PID_NS
7135 	perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7136 			       task, &pidns_operations);
7137 #endif
7138 #ifdef CONFIG_CGROUPS
7139 	perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7140 			       task, &cgroupns_operations);
7141 #endif
7142 
7143 	perf_iterate_sb(perf_event_namespaces_output,
7144 			&namespaces_event,
7145 			NULL);
7146 }
7147 
7148 /*
7149  * mmap tracking
7150  */
7151 
7152 struct perf_mmap_event {
7153 	struct vm_area_struct	*vma;
7154 
7155 	const char		*file_name;
7156 	int			file_size;
7157 	int			maj, min;
7158 	u64			ino;
7159 	u64			ino_generation;
7160 	u32			prot, flags;
7161 
7162 	struct {
7163 		struct perf_event_header	header;
7164 
7165 		u32				pid;
7166 		u32				tid;
7167 		u64				start;
7168 		u64				len;
7169 		u64				pgoff;
7170 	} event_id;
7171 };
7172 
7173 static int perf_event_mmap_match(struct perf_event *event,
7174 				 void *data)
7175 {
7176 	struct perf_mmap_event *mmap_event = data;
7177 	struct vm_area_struct *vma = mmap_event->vma;
7178 	int executable = vma->vm_flags & VM_EXEC;
7179 
7180 	return (!executable && event->attr.mmap_data) ||
7181 	       (executable && (event->attr.mmap || event->attr.mmap2));
7182 }
7183 
7184 static void perf_event_mmap_output(struct perf_event *event,
7185 				   void *data)
7186 {
7187 	struct perf_mmap_event *mmap_event = data;
7188 	struct perf_output_handle handle;
7189 	struct perf_sample_data sample;
7190 	int size = mmap_event->event_id.header.size;
7191 	int ret;
7192 
7193 	if (!perf_event_mmap_match(event, data))
7194 		return;
7195 
7196 	if (event->attr.mmap2) {
7197 		mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7198 		mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7199 		mmap_event->event_id.header.size += sizeof(mmap_event->min);
7200 		mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7201 		mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7202 		mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7203 		mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7204 	}
7205 
7206 	perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7207 	ret = perf_output_begin(&handle, event,
7208 				mmap_event->event_id.header.size);
7209 	if (ret)
7210 		goto out;
7211 
7212 	mmap_event->event_id.pid = perf_event_pid(event, current);
7213 	mmap_event->event_id.tid = perf_event_tid(event, current);
7214 
7215 	perf_output_put(&handle, mmap_event->event_id);
7216 
7217 	if (event->attr.mmap2) {
7218 		perf_output_put(&handle, mmap_event->maj);
7219 		perf_output_put(&handle, mmap_event->min);
7220 		perf_output_put(&handle, mmap_event->ino);
7221 		perf_output_put(&handle, mmap_event->ino_generation);
7222 		perf_output_put(&handle, mmap_event->prot);
7223 		perf_output_put(&handle, mmap_event->flags);
7224 	}
7225 
7226 	__output_copy(&handle, mmap_event->file_name,
7227 				   mmap_event->file_size);
7228 
7229 	perf_event__output_id_sample(event, &handle, &sample);
7230 
7231 	perf_output_end(&handle);
7232 out:
7233 	mmap_event->event_id.header.size = size;
7234 }
7235 
7236 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7237 {
7238 	struct vm_area_struct *vma = mmap_event->vma;
7239 	struct file *file = vma->vm_file;
7240 	int maj = 0, min = 0;
7241 	u64 ino = 0, gen = 0;
7242 	u32 prot = 0, flags = 0;
7243 	unsigned int size;
7244 	char tmp[16];
7245 	char *buf = NULL;
7246 	char *name;
7247 
7248 	if (vma->vm_flags & VM_READ)
7249 		prot |= PROT_READ;
7250 	if (vma->vm_flags & VM_WRITE)
7251 		prot |= PROT_WRITE;
7252 	if (vma->vm_flags & VM_EXEC)
7253 		prot |= PROT_EXEC;
7254 
7255 	if (vma->vm_flags & VM_MAYSHARE)
7256 		flags = MAP_SHARED;
7257 	else
7258 		flags = MAP_PRIVATE;
7259 
7260 	if (vma->vm_flags & VM_DENYWRITE)
7261 		flags |= MAP_DENYWRITE;
7262 	if (vma->vm_flags & VM_MAYEXEC)
7263 		flags |= MAP_EXECUTABLE;
7264 	if (vma->vm_flags & VM_LOCKED)
7265 		flags |= MAP_LOCKED;
7266 	if (vma->vm_flags & VM_HUGETLB)
7267 		flags |= MAP_HUGETLB;
7268 
7269 	if (file) {
7270 		struct inode *inode;
7271 		dev_t dev;
7272 
7273 		buf = kmalloc(PATH_MAX, GFP_KERNEL);
7274 		if (!buf) {
7275 			name = "//enomem";
7276 			goto cpy_name;
7277 		}
7278 		/*
7279 		 * d_path() works from the end of the rb backwards, so we
7280 		 * need to add enough zero bytes after the string to handle
7281 		 * the 64bit alignment we do later.
7282 		 */
7283 		name = file_path(file, buf, PATH_MAX - sizeof(u64));
7284 		if (IS_ERR(name)) {
7285 			name = "//toolong";
7286 			goto cpy_name;
7287 		}
7288 		inode = file_inode(vma->vm_file);
7289 		dev = inode->i_sb->s_dev;
7290 		ino = inode->i_ino;
7291 		gen = inode->i_generation;
7292 		maj = MAJOR(dev);
7293 		min = MINOR(dev);
7294 
7295 		goto got_name;
7296 	} else {
7297 		if (vma->vm_ops && vma->vm_ops->name) {
7298 			name = (char *) vma->vm_ops->name(vma);
7299 			if (name)
7300 				goto cpy_name;
7301 		}
7302 
7303 		name = (char *)arch_vma_name(vma);
7304 		if (name)
7305 			goto cpy_name;
7306 
7307 		if (vma->vm_start <= vma->vm_mm->start_brk &&
7308 				vma->vm_end >= vma->vm_mm->brk) {
7309 			name = "[heap]";
7310 			goto cpy_name;
7311 		}
7312 		if (vma->vm_start <= vma->vm_mm->start_stack &&
7313 				vma->vm_end >= vma->vm_mm->start_stack) {
7314 			name = "[stack]";
7315 			goto cpy_name;
7316 		}
7317 
7318 		name = "//anon";
7319 		goto cpy_name;
7320 	}
7321 
7322 cpy_name:
7323 	strlcpy(tmp, name, sizeof(tmp));
7324 	name = tmp;
7325 got_name:
7326 	/*
7327 	 * Since our buffer works in 8 byte units we need to align our string
7328 	 * size to a multiple of 8. However, we must guarantee the tail end is
7329 	 * zero'd out to avoid leaking random bits to userspace.
7330 	 */
7331 	size = strlen(name)+1;
7332 	while (!IS_ALIGNED(size, sizeof(u64)))
7333 		name[size++] = '\0';
7334 
7335 	mmap_event->file_name = name;
7336 	mmap_event->file_size = size;
7337 	mmap_event->maj = maj;
7338 	mmap_event->min = min;
7339 	mmap_event->ino = ino;
7340 	mmap_event->ino_generation = gen;
7341 	mmap_event->prot = prot;
7342 	mmap_event->flags = flags;
7343 
7344 	if (!(vma->vm_flags & VM_EXEC))
7345 		mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7346 
7347 	mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7348 
7349 	perf_iterate_sb(perf_event_mmap_output,
7350 		       mmap_event,
7351 		       NULL);
7352 
7353 	kfree(buf);
7354 }
7355 
7356 /*
7357  * Check whether inode and address range match filter criteria.
7358  */
7359 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7360 				     struct file *file, unsigned long offset,
7361 				     unsigned long size)
7362 {
7363 	/* d_inode(NULL) won't be equal to any mapped user-space file */
7364 	if (!filter->path.dentry)
7365 		return false;
7366 
7367 	if (d_inode(filter->path.dentry) != file_inode(file))
7368 		return false;
7369 
7370 	if (filter->offset > offset + size)
7371 		return false;
7372 
7373 	if (filter->offset + filter->size < offset)
7374 		return false;
7375 
7376 	return true;
7377 }
7378 
7379 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
7380 					struct vm_area_struct *vma,
7381 					struct perf_addr_filter_range *fr)
7382 {
7383 	unsigned long vma_size = vma->vm_end - vma->vm_start;
7384 	unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
7385 	struct file *file = vma->vm_file;
7386 
7387 	if (!perf_addr_filter_match(filter, file, off, vma_size))
7388 		return false;
7389 
7390 	if (filter->offset < off) {
7391 		fr->start = vma->vm_start;
7392 		fr->size = min(vma_size, filter->size - (off - filter->offset));
7393 	} else {
7394 		fr->start = vma->vm_start + filter->offset - off;
7395 		fr->size = min(vma->vm_end - fr->start, filter->size);
7396 	}
7397 
7398 	return true;
7399 }
7400 
7401 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7402 {
7403 	struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7404 	struct vm_area_struct *vma = data;
7405 	struct perf_addr_filter *filter;
7406 	unsigned int restart = 0, count = 0;
7407 	unsigned long flags;
7408 
7409 	if (!has_addr_filter(event))
7410 		return;
7411 
7412 	if (!vma->vm_file)
7413 		return;
7414 
7415 	raw_spin_lock_irqsave(&ifh->lock, flags);
7416 	list_for_each_entry(filter, &ifh->list, entry) {
7417 		if (perf_addr_filter_vma_adjust(filter, vma,
7418 						&event->addr_filter_ranges[count]))
7419 			restart++;
7420 
7421 		count++;
7422 	}
7423 
7424 	if (restart)
7425 		event->addr_filters_gen++;
7426 	raw_spin_unlock_irqrestore(&ifh->lock, flags);
7427 
7428 	if (restart)
7429 		perf_event_stop(event, 1);
7430 }
7431 
7432 /*
7433  * Adjust all task's events' filters to the new vma
7434  */
7435 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7436 {
7437 	struct perf_event_context *ctx;
7438 	int ctxn;
7439 
7440 	/*
7441 	 * Data tracing isn't supported yet and as such there is no need
7442 	 * to keep track of anything that isn't related to executable code:
7443 	 */
7444 	if (!(vma->vm_flags & VM_EXEC))
7445 		return;
7446 
7447 	rcu_read_lock();
7448 	for_each_task_context_nr(ctxn) {
7449 		ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7450 		if (!ctx)
7451 			continue;
7452 
7453 		perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7454 	}
7455 	rcu_read_unlock();
7456 }
7457 
7458 void perf_event_mmap(struct vm_area_struct *vma)
7459 {
7460 	struct perf_mmap_event mmap_event;
7461 
7462 	if (!atomic_read(&nr_mmap_events))
7463 		return;
7464 
7465 	mmap_event = (struct perf_mmap_event){
7466 		.vma	= vma,
7467 		/* .file_name */
7468 		/* .file_size */
7469 		.event_id  = {
7470 			.header = {
7471 				.type = PERF_RECORD_MMAP,
7472 				.misc = PERF_RECORD_MISC_USER,
7473 				/* .size */
7474 			},
7475 			/* .pid */
7476 			/* .tid */
7477 			.start  = vma->vm_start,
7478 			.len    = vma->vm_end - vma->vm_start,
7479 			.pgoff  = (u64)vma->vm_pgoff << PAGE_SHIFT,
7480 		},
7481 		/* .maj (attr_mmap2 only) */
7482 		/* .min (attr_mmap2 only) */
7483 		/* .ino (attr_mmap2 only) */
7484 		/* .ino_generation (attr_mmap2 only) */
7485 		/* .prot (attr_mmap2 only) */
7486 		/* .flags (attr_mmap2 only) */
7487 	};
7488 
7489 	perf_addr_filters_adjust(vma);
7490 	perf_event_mmap_event(&mmap_event);
7491 }
7492 
7493 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7494 			  unsigned long size, u64 flags)
7495 {
7496 	struct perf_output_handle handle;
7497 	struct perf_sample_data sample;
7498 	struct perf_aux_event {
7499 		struct perf_event_header	header;
7500 		u64				offset;
7501 		u64				size;
7502 		u64				flags;
7503 	} rec = {
7504 		.header = {
7505 			.type = PERF_RECORD_AUX,
7506 			.misc = 0,
7507 			.size = sizeof(rec),
7508 		},
7509 		.offset		= head,
7510 		.size		= size,
7511 		.flags		= flags,
7512 	};
7513 	int ret;
7514 
7515 	perf_event_header__init_id(&rec.header, &sample, event);
7516 	ret = perf_output_begin(&handle, event, rec.header.size);
7517 
7518 	if (ret)
7519 		return;
7520 
7521 	perf_output_put(&handle, rec);
7522 	perf_event__output_id_sample(event, &handle, &sample);
7523 
7524 	perf_output_end(&handle);
7525 }
7526 
7527 /*
7528  * Lost/dropped samples logging
7529  */
7530 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7531 {
7532 	struct perf_output_handle handle;
7533 	struct perf_sample_data sample;
7534 	int ret;
7535 
7536 	struct {
7537 		struct perf_event_header	header;
7538 		u64				lost;
7539 	} lost_samples_event = {
7540 		.header = {
7541 			.type = PERF_RECORD_LOST_SAMPLES,
7542 			.misc = 0,
7543 			.size = sizeof(lost_samples_event),
7544 		},
7545 		.lost		= lost,
7546 	};
7547 
7548 	perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7549 
7550 	ret = perf_output_begin(&handle, event,
7551 				lost_samples_event.header.size);
7552 	if (ret)
7553 		return;
7554 
7555 	perf_output_put(&handle, lost_samples_event);
7556 	perf_event__output_id_sample(event, &handle, &sample);
7557 	perf_output_end(&handle);
7558 }
7559 
7560 /*
7561  * context_switch tracking
7562  */
7563 
7564 struct perf_switch_event {
7565 	struct task_struct	*task;
7566 	struct task_struct	*next_prev;
7567 
7568 	struct {
7569 		struct perf_event_header	header;
7570 		u32				next_prev_pid;
7571 		u32				next_prev_tid;
7572 	} event_id;
7573 };
7574 
7575 static int perf_event_switch_match(struct perf_event *event)
7576 {
7577 	return event->attr.context_switch;
7578 }
7579 
7580 static void perf_event_switch_output(struct perf_event *event, void *data)
7581 {
7582 	struct perf_switch_event *se = data;
7583 	struct perf_output_handle handle;
7584 	struct perf_sample_data sample;
7585 	int ret;
7586 
7587 	if (!perf_event_switch_match(event))
7588 		return;
7589 
7590 	/* Only CPU-wide events are allowed to see next/prev pid/tid */
7591 	if (event->ctx->task) {
7592 		se->event_id.header.type = PERF_RECORD_SWITCH;
7593 		se->event_id.header.size = sizeof(se->event_id.header);
7594 	} else {
7595 		se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7596 		se->event_id.header.size = sizeof(se->event_id);
7597 		se->event_id.next_prev_pid =
7598 					perf_event_pid(event, se->next_prev);
7599 		se->event_id.next_prev_tid =
7600 					perf_event_tid(event, se->next_prev);
7601 	}
7602 
7603 	perf_event_header__init_id(&se->event_id.header, &sample, event);
7604 
7605 	ret = perf_output_begin(&handle, event, se->event_id.header.size);
7606 	if (ret)
7607 		return;
7608 
7609 	if (event->ctx->task)
7610 		perf_output_put(&handle, se->event_id.header);
7611 	else
7612 		perf_output_put(&handle, se->event_id);
7613 
7614 	perf_event__output_id_sample(event, &handle, &sample);
7615 
7616 	perf_output_end(&handle);
7617 }
7618 
7619 static void perf_event_switch(struct task_struct *task,
7620 			      struct task_struct *next_prev, bool sched_in)
7621 {
7622 	struct perf_switch_event switch_event;
7623 
7624 	/* N.B. caller checks nr_switch_events != 0 */
7625 
7626 	switch_event = (struct perf_switch_event){
7627 		.task		= task,
7628 		.next_prev	= next_prev,
7629 		.event_id	= {
7630 			.header = {
7631 				/* .type */
7632 				.misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7633 				/* .size */
7634 			},
7635 			/* .next_prev_pid */
7636 			/* .next_prev_tid */
7637 		},
7638 	};
7639 
7640 	if (!sched_in && task->state == TASK_RUNNING)
7641 		switch_event.event_id.header.misc |=
7642 				PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
7643 
7644 	perf_iterate_sb(perf_event_switch_output,
7645 		       &switch_event,
7646 		       NULL);
7647 }
7648 
7649 /*
7650  * IRQ throttle logging
7651  */
7652 
7653 static void perf_log_throttle(struct perf_event *event, int enable)
7654 {
7655 	struct perf_output_handle handle;
7656 	struct perf_sample_data sample;
7657 	int ret;
7658 
7659 	struct {
7660 		struct perf_event_header	header;
7661 		u64				time;
7662 		u64				id;
7663 		u64				stream_id;
7664 	} throttle_event = {
7665 		.header = {
7666 			.type = PERF_RECORD_THROTTLE,
7667 			.misc = 0,
7668 			.size = sizeof(throttle_event),
7669 		},
7670 		.time		= perf_event_clock(event),
7671 		.id		= primary_event_id(event),
7672 		.stream_id	= event->id,
7673 	};
7674 
7675 	if (enable)
7676 		throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7677 
7678 	perf_event_header__init_id(&throttle_event.header, &sample, event);
7679 
7680 	ret = perf_output_begin(&handle, event,
7681 				throttle_event.header.size);
7682 	if (ret)
7683 		return;
7684 
7685 	perf_output_put(&handle, throttle_event);
7686 	perf_event__output_id_sample(event, &handle, &sample);
7687 	perf_output_end(&handle);
7688 }
7689 
7690 /*
7691  * ksymbol register/unregister tracking
7692  */
7693 
7694 struct perf_ksymbol_event {
7695 	const char	*name;
7696 	int		name_len;
7697 	struct {
7698 		struct perf_event_header        header;
7699 		u64				addr;
7700 		u32				len;
7701 		u16				ksym_type;
7702 		u16				flags;
7703 	} event_id;
7704 };
7705 
7706 static int perf_event_ksymbol_match(struct perf_event *event)
7707 {
7708 	return event->attr.ksymbol;
7709 }
7710 
7711 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
7712 {
7713 	struct perf_ksymbol_event *ksymbol_event = data;
7714 	struct perf_output_handle handle;
7715 	struct perf_sample_data sample;
7716 	int ret;
7717 
7718 	if (!perf_event_ksymbol_match(event))
7719 		return;
7720 
7721 	perf_event_header__init_id(&ksymbol_event->event_id.header,
7722 				   &sample, event);
7723 	ret = perf_output_begin(&handle, event,
7724 				ksymbol_event->event_id.header.size);
7725 	if (ret)
7726 		return;
7727 
7728 	perf_output_put(&handle, ksymbol_event->event_id);
7729 	__output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
7730 	perf_event__output_id_sample(event, &handle, &sample);
7731 
7732 	perf_output_end(&handle);
7733 }
7734 
7735 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
7736 			const char *sym)
7737 {
7738 	struct perf_ksymbol_event ksymbol_event;
7739 	char name[KSYM_NAME_LEN];
7740 	u16 flags = 0;
7741 	int name_len;
7742 
7743 	if (!atomic_read(&nr_ksymbol_events))
7744 		return;
7745 
7746 	if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
7747 	    ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
7748 		goto err;
7749 
7750 	strlcpy(name, sym, KSYM_NAME_LEN);
7751 	name_len = strlen(name) + 1;
7752 	while (!IS_ALIGNED(name_len, sizeof(u64)))
7753 		name[name_len++] = '\0';
7754 	BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
7755 
7756 	if (unregister)
7757 		flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
7758 
7759 	ksymbol_event = (struct perf_ksymbol_event){
7760 		.name = name,
7761 		.name_len = name_len,
7762 		.event_id = {
7763 			.header = {
7764 				.type = PERF_RECORD_KSYMBOL,
7765 				.size = sizeof(ksymbol_event.event_id) +
7766 					name_len,
7767 			},
7768 			.addr = addr,
7769 			.len = len,
7770 			.ksym_type = ksym_type,
7771 			.flags = flags,
7772 		},
7773 	};
7774 
7775 	perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
7776 	return;
7777 err:
7778 	WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
7779 }
7780 
7781 /*
7782  * bpf program load/unload tracking
7783  */
7784 
7785 struct perf_bpf_event {
7786 	struct bpf_prog	*prog;
7787 	struct {
7788 		struct perf_event_header        header;
7789 		u16				type;
7790 		u16				flags;
7791 		u32				id;
7792 		u8				tag[BPF_TAG_SIZE];
7793 	} event_id;
7794 };
7795 
7796 static int perf_event_bpf_match(struct perf_event *event)
7797 {
7798 	return event->attr.bpf_event;
7799 }
7800 
7801 static void perf_event_bpf_output(struct perf_event *event, void *data)
7802 {
7803 	struct perf_bpf_event *bpf_event = data;
7804 	struct perf_output_handle handle;
7805 	struct perf_sample_data sample;
7806 	int ret;
7807 
7808 	if (!perf_event_bpf_match(event))
7809 		return;
7810 
7811 	perf_event_header__init_id(&bpf_event->event_id.header,
7812 				   &sample, event);
7813 	ret = perf_output_begin(&handle, event,
7814 				bpf_event->event_id.header.size);
7815 	if (ret)
7816 		return;
7817 
7818 	perf_output_put(&handle, bpf_event->event_id);
7819 	perf_event__output_id_sample(event, &handle, &sample);
7820 
7821 	perf_output_end(&handle);
7822 }
7823 
7824 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
7825 					 enum perf_bpf_event_type type)
7826 {
7827 	bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
7828 	char sym[KSYM_NAME_LEN];
7829 	int i;
7830 
7831 	if (prog->aux->func_cnt == 0) {
7832 		bpf_get_prog_name(prog, sym);
7833 		perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
7834 				   (u64)(unsigned long)prog->bpf_func,
7835 				   prog->jited_len, unregister, sym);
7836 	} else {
7837 		for (i = 0; i < prog->aux->func_cnt; i++) {
7838 			struct bpf_prog *subprog = prog->aux->func[i];
7839 
7840 			bpf_get_prog_name(subprog, sym);
7841 			perf_event_ksymbol(
7842 				PERF_RECORD_KSYMBOL_TYPE_BPF,
7843 				(u64)(unsigned long)subprog->bpf_func,
7844 				subprog->jited_len, unregister, sym);
7845 		}
7846 	}
7847 }
7848 
7849 void perf_event_bpf_event(struct bpf_prog *prog,
7850 			  enum perf_bpf_event_type type,
7851 			  u16 flags)
7852 {
7853 	struct perf_bpf_event bpf_event;
7854 
7855 	if (type <= PERF_BPF_EVENT_UNKNOWN ||
7856 	    type >= PERF_BPF_EVENT_MAX)
7857 		return;
7858 
7859 	switch (type) {
7860 	case PERF_BPF_EVENT_PROG_LOAD:
7861 	case PERF_BPF_EVENT_PROG_UNLOAD:
7862 		if (atomic_read(&nr_ksymbol_events))
7863 			perf_event_bpf_emit_ksymbols(prog, type);
7864 		break;
7865 	default:
7866 		break;
7867 	}
7868 
7869 	if (!atomic_read(&nr_bpf_events))
7870 		return;
7871 
7872 	bpf_event = (struct perf_bpf_event){
7873 		.prog = prog,
7874 		.event_id = {
7875 			.header = {
7876 				.type = PERF_RECORD_BPF_EVENT,
7877 				.size = sizeof(bpf_event.event_id),
7878 			},
7879 			.type = type,
7880 			.flags = flags,
7881 			.id = prog->aux->id,
7882 		},
7883 	};
7884 
7885 	BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
7886 
7887 	memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
7888 	perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
7889 }
7890 
7891 void perf_event_itrace_started(struct perf_event *event)
7892 {
7893 	event->attach_state |= PERF_ATTACH_ITRACE;
7894 }
7895 
7896 static void perf_log_itrace_start(struct perf_event *event)
7897 {
7898 	struct perf_output_handle handle;
7899 	struct perf_sample_data sample;
7900 	struct perf_aux_event {
7901 		struct perf_event_header        header;
7902 		u32				pid;
7903 		u32				tid;
7904 	} rec;
7905 	int ret;
7906 
7907 	if (event->parent)
7908 		event = event->parent;
7909 
7910 	if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7911 	    event->attach_state & PERF_ATTACH_ITRACE)
7912 		return;
7913 
7914 	rec.header.type	= PERF_RECORD_ITRACE_START;
7915 	rec.header.misc	= 0;
7916 	rec.header.size	= sizeof(rec);
7917 	rec.pid	= perf_event_pid(event, current);
7918 	rec.tid	= perf_event_tid(event, current);
7919 
7920 	perf_event_header__init_id(&rec.header, &sample, event);
7921 	ret = perf_output_begin(&handle, event, rec.header.size);
7922 
7923 	if (ret)
7924 		return;
7925 
7926 	perf_output_put(&handle, rec);
7927 	perf_event__output_id_sample(event, &handle, &sample);
7928 
7929 	perf_output_end(&handle);
7930 }
7931 
7932 static int
7933 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7934 {
7935 	struct hw_perf_event *hwc = &event->hw;
7936 	int ret = 0;
7937 	u64 seq;
7938 
7939 	seq = __this_cpu_read(perf_throttled_seq);
7940 	if (seq != hwc->interrupts_seq) {
7941 		hwc->interrupts_seq = seq;
7942 		hwc->interrupts = 1;
7943 	} else {
7944 		hwc->interrupts++;
7945 		if (unlikely(throttle
7946 			     && hwc->interrupts >= max_samples_per_tick)) {
7947 			__this_cpu_inc(perf_throttled_count);
7948 			tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7949 			hwc->interrupts = MAX_INTERRUPTS;
7950 			perf_log_throttle(event, 0);
7951 			ret = 1;
7952 		}
7953 	}
7954 
7955 	if (event->attr.freq) {
7956 		u64 now = perf_clock();
7957 		s64 delta = now - hwc->freq_time_stamp;
7958 
7959 		hwc->freq_time_stamp = now;
7960 
7961 		if (delta > 0 && delta < 2*TICK_NSEC)
7962 			perf_adjust_period(event, delta, hwc->last_period, true);
7963 	}
7964 
7965 	return ret;
7966 }
7967 
7968 int perf_event_account_interrupt(struct perf_event *event)
7969 {
7970 	return __perf_event_account_interrupt(event, 1);
7971 }
7972 
7973 /*
7974  * Generic event overflow handling, sampling.
7975  */
7976 
7977 static int __perf_event_overflow(struct perf_event *event,
7978 				   int throttle, struct perf_sample_data *data,
7979 				   struct pt_regs *regs)
7980 {
7981 	int events = atomic_read(&event->event_limit);
7982 	int ret = 0;
7983 
7984 	/*
7985 	 * Non-sampling counters might still use the PMI to fold short
7986 	 * hardware counters, ignore those.
7987 	 */
7988 	if (unlikely(!is_sampling_event(event)))
7989 		return 0;
7990 
7991 	ret = __perf_event_account_interrupt(event, throttle);
7992 
7993 	/*
7994 	 * XXX event_limit might not quite work as expected on inherited
7995 	 * events
7996 	 */
7997 
7998 	event->pending_kill = POLL_IN;
7999 	if (events && atomic_dec_and_test(&event->event_limit)) {
8000 		ret = 1;
8001 		event->pending_kill = POLL_HUP;
8002 
8003 		perf_event_disable_inatomic(event);
8004 	}
8005 
8006 	READ_ONCE(event->overflow_handler)(event, data, regs);
8007 
8008 	if (*perf_event_fasync(event) && event->pending_kill) {
8009 		event->pending_wakeup = 1;
8010 		irq_work_queue(&event->pending);
8011 	}
8012 
8013 	return ret;
8014 }
8015 
8016 int perf_event_overflow(struct perf_event *event,
8017 			  struct perf_sample_data *data,
8018 			  struct pt_regs *regs)
8019 {
8020 	return __perf_event_overflow(event, 1, data, regs);
8021 }
8022 
8023 /*
8024  * Generic software event infrastructure
8025  */
8026 
8027 struct swevent_htable {
8028 	struct swevent_hlist		*swevent_hlist;
8029 	struct mutex			hlist_mutex;
8030 	int				hlist_refcount;
8031 
8032 	/* Recursion avoidance in each contexts */
8033 	int				recursion[PERF_NR_CONTEXTS];
8034 };
8035 
8036 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
8037 
8038 /*
8039  * We directly increment event->count and keep a second value in
8040  * event->hw.period_left to count intervals. This period event
8041  * is kept in the range [-sample_period, 0] so that we can use the
8042  * sign as trigger.
8043  */
8044 
8045 u64 perf_swevent_set_period(struct perf_event *event)
8046 {
8047 	struct hw_perf_event *hwc = &event->hw;
8048 	u64 period = hwc->last_period;
8049 	u64 nr, offset;
8050 	s64 old, val;
8051 
8052 	hwc->last_period = hwc->sample_period;
8053 
8054 again:
8055 	old = val = local64_read(&hwc->period_left);
8056 	if (val < 0)
8057 		return 0;
8058 
8059 	nr = div64_u64(period + val, period);
8060 	offset = nr * period;
8061 	val -= offset;
8062 	if (local64_cmpxchg(&hwc->period_left, old, val) != old)
8063 		goto again;
8064 
8065 	return nr;
8066 }
8067 
8068 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
8069 				    struct perf_sample_data *data,
8070 				    struct pt_regs *regs)
8071 {
8072 	struct hw_perf_event *hwc = &event->hw;
8073 	int throttle = 0;
8074 
8075 	if (!overflow)
8076 		overflow = perf_swevent_set_period(event);
8077 
8078 	if (hwc->interrupts == MAX_INTERRUPTS)
8079 		return;
8080 
8081 	for (; overflow; overflow--) {
8082 		if (__perf_event_overflow(event, throttle,
8083 					    data, regs)) {
8084 			/*
8085 			 * We inhibit the overflow from happening when
8086 			 * hwc->interrupts == MAX_INTERRUPTS.
8087 			 */
8088 			break;
8089 		}
8090 		throttle = 1;
8091 	}
8092 }
8093 
8094 static void perf_swevent_event(struct perf_event *event, u64 nr,
8095 			       struct perf_sample_data *data,
8096 			       struct pt_regs *regs)
8097 {
8098 	struct hw_perf_event *hwc = &event->hw;
8099 
8100 	local64_add(nr, &event->count);
8101 
8102 	if (!regs)
8103 		return;
8104 
8105 	if (!is_sampling_event(event))
8106 		return;
8107 
8108 	if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
8109 		data->period = nr;
8110 		return perf_swevent_overflow(event, 1, data, regs);
8111 	} else
8112 		data->period = event->hw.last_period;
8113 
8114 	if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
8115 		return perf_swevent_overflow(event, 1, data, regs);
8116 
8117 	if (local64_add_negative(nr, &hwc->period_left))
8118 		return;
8119 
8120 	perf_swevent_overflow(event, 0, data, regs);
8121 }
8122 
8123 static int perf_exclude_event(struct perf_event *event,
8124 			      struct pt_regs *regs)
8125 {
8126 	if (event->hw.state & PERF_HES_STOPPED)
8127 		return 1;
8128 
8129 	if (regs) {
8130 		if (event->attr.exclude_user && user_mode(regs))
8131 			return 1;
8132 
8133 		if (event->attr.exclude_kernel && !user_mode(regs))
8134 			return 1;
8135 	}
8136 
8137 	return 0;
8138 }
8139 
8140 static int perf_swevent_match(struct perf_event *event,
8141 				enum perf_type_id type,
8142 				u32 event_id,
8143 				struct perf_sample_data *data,
8144 				struct pt_regs *regs)
8145 {
8146 	if (event->attr.type != type)
8147 		return 0;
8148 
8149 	if (event->attr.config != event_id)
8150 		return 0;
8151 
8152 	if (perf_exclude_event(event, regs))
8153 		return 0;
8154 
8155 	return 1;
8156 }
8157 
8158 static inline u64 swevent_hash(u64 type, u32 event_id)
8159 {
8160 	u64 val = event_id | (type << 32);
8161 
8162 	return hash_64(val, SWEVENT_HLIST_BITS);
8163 }
8164 
8165 static inline struct hlist_head *
8166 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
8167 {
8168 	u64 hash = swevent_hash(type, event_id);
8169 
8170 	return &hlist->heads[hash];
8171 }
8172 
8173 /* For the read side: events when they trigger */
8174 static inline struct hlist_head *
8175 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
8176 {
8177 	struct swevent_hlist *hlist;
8178 
8179 	hlist = rcu_dereference(swhash->swevent_hlist);
8180 	if (!hlist)
8181 		return NULL;
8182 
8183 	return __find_swevent_head(hlist, type, event_id);
8184 }
8185 
8186 /* For the event head insertion and removal in the hlist */
8187 static inline struct hlist_head *
8188 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
8189 {
8190 	struct swevent_hlist *hlist;
8191 	u32 event_id = event->attr.config;
8192 	u64 type = event->attr.type;
8193 
8194 	/*
8195 	 * Event scheduling is always serialized against hlist allocation
8196 	 * and release. Which makes the protected version suitable here.
8197 	 * The context lock guarantees that.
8198 	 */
8199 	hlist = rcu_dereference_protected(swhash->swevent_hlist,
8200 					  lockdep_is_held(&event->ctx->lock));
8201 	if (!hlist)
8202 		return NULL;
8203 
8204 	return __find_swevent_head(hlist, type, event_id);
8205 }
8206 
8207 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
8208 				    u64 nr,
8209 				    struct perf_sample_data *data,
8210 				    struct pt_regs *regs)
8211 {
8212 	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8213 	struct perf_event *event;
8214 	struct hlist_head *head;
8215 
8216 	rcu_read_lock();
8217 	head = find_swevent_head_rcu(swhash, type, event_id);
8218 	if (!head)
8219 		goto end;
8220 
8221 	hlist_for_each_entry_rcu(event, head, hlist_entry) {
8222 		if (perf_swevent_match(event, type, event_id, data, regs))
8223 			perf_swevent_event(event, nr, data, regs);
8224 	}
8225 end:
8226 	rcu_read_unlock();
8227 }
8228 
8229 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
8230 
8231 int perf_swevent_get_recursion_context(void)
8232 {
8233 	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8234 
8235 	return get_recursion_context(swhash->recursion);
8236 }
8237 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
8238 
8239 void perf_swevent_put_recursion_context(int rctx)
8240 {
8241 	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8242 
8243 	put_recursion_context(swhash->recursion, rctx);
8244 }
8245 
8246 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8247 {
8248 	struct perf_sample_data data;
8249 
8250 	if (WARN_ON_ONCE(!regs))
8251 		return;
8252 
8253 	perf_sample_data_init(&data, addr, 0);
8254 	do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
8255 }
8256 
8257 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8258 {
8259 	int rctx;
8260 
8261 	preempt_disable_notrace();
8262 	rctx = perf_swevent_get_recursion_context();
8263 	if (unlikely(rctx < 0))
8264 		goto fail;
8265 
8266 	___perf_sw_event(event_id, nr, regs, addr);
8267 
8268 	perf_swevent_put_recursion_context(rctx);
8269 fail:
8270 	preempt_enable_notrace();
8271 }
8272 
8273 static void perf_swevent_read(struct perf_event *event)
8274 {
8275 }
8276 
8277 static int perf_swevent_add(struct perf_event *event, int flags)
8278 {
8279 	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8280 	struct hw_perf_event *hwc = &event->hw;
8281 	struct hlist_head *head;
8282 
8283 	if (is_sampling_event(event)) {
8284 		hwc->last_period = hwc->sample_period;
8285 		perf_swevent_set_period(event);
8286 	}
8287 
8288 	hwc->state = !(flags & PERF_EF_START);
8289 
8290 	head = find_swevent_head(swhash, event);
8291 	if (WARN_ON_ONCE(!head))
8292 		return -EINVAL;
8293 
8294 	hlist_add_head_rcu(&event->hlist_entry, head);
8295 	perf_event_update_userpage(event);
8296 
8297 	return 0;
8298 }
8299 
8300 static void perf_swevent_del(struct perf_event *event, int flags)
8301 {
8302 	hlist_del_rcu(&event->hlist_entry);
8303 }
8304 
8305 static void perf_swevent_start(struct perf_event *event, int flags)
8306 {
8307 	event->hw.state = 0;
8308 }
8309 
8310 static void perf_swevent_stop(struct perf_event *event, int flags)
8311 {
8312 	event->hw.state = PERF_HES_STOPPED;
8313 }
8314 
8315 /* Deref the hlist from the update side */
8316 static inline struct swevent_hlist *
8317 swevent_hlist_deref(struct swevent_htable *swhash)
8318 {
8319 	return rcu_dereference_protected(swhash->swevent_hlist,
8320 					 lockdep_is_held(&swhash->hlist_mutex));
8321 }
8322 
8323 static void swevent_hlist_release(struct swevent_htable *swhash)
8324 {
8325 	struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
8326 
8327 	if (!hlist)
8328 		return;
8329 
8330 	RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
8331 	kfree_rcu(hlist, rcu_head);
8332 }
8333 
8334 static void swevent_hlist_put_cpu(int cpu)
8335 {
8336 	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8337 
8338 	mutex_lock(&swhash->hlist_mutex);
8339 
8340 	if (!--swhash->hlist_refcount)
8341 		swevent_hlist_release(swhash);
8342 
8343 	mutex_unlock(&swhash->hlist_mutex);
8344 }
8345 
8346 static void swevent_hlist_put(void)
8347 {
8348 	int cpu;
8349 
8350 	for_each_possible_cpu(cpu)
8351 		swevent_hlist_put_cpu(cpu);
8352 }
8353 
8354 static int swevent_hlist_get_cpu(int cpu)
8355 {
8356 	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8357 	int err = 0;
8358 
8359 	mutex_lock(&swhash->hlist_mutex);
8360 	if (!swevent_hlist_deref(swhash) &&
8361 	    cpumask_test_cpu(cpu, perf_online_mask)) {
8362 		struct swevent_hlist *hlist;
8363 
8364 		hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
8365 		if (!hlist) {
8366 			err = -ENOMEM;
8367 			goto exit;
8368 		}
8369 		rcu_assign_pointer(swhash->swevent_hlist, hlist);
8370 	}
8371 	swhash->hlist_refcount++;
8372 exit:
8373 	mutex_unlock(&swhash->hlist_mutex);
8374 
8375 	return err;
8376 }
8377 
8378 static int swevent_hlist_get(void)
8379 {
8380 	int err, cpu, failed_cpu;
8381 
8382 	mutex_lock(&pmus_lock);
8383 	for_each_possible_cpu(cpu) {
8384 		err = swevent_hlist_get_cpu(cpu);
8385 		if (err) {
8386 			failed_cpu = cpu;
8387 			goto fail;
8388 		}
8389 	}
8390 	mutex_unlock(&pmus_lock);
8391 	return 0;
8392 fail:
8393 	for_each_possible_cpu(cpu) {
8394 		if (cpu == failed_cpu)
8395 			break;
8396 		swevent_hlist_put_cpu(cpu);
8397 	}
8398 	mutex_unlock(&pmus_lock);
8399 	return err;
8400 }
8401 
8402 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
8403 
8404 static void sw_perf_event_destroy(struct perf_event *event)
8405 {
8406 	u64 event_id = event->attr.config;
8407 
8408 	WARN_ON(event->parent);
8409 
8410 	static_key_slow_dec(&perf_swevent_enabled[event_id]);
8411 	swevent_hlist_put();
8412 }
8413 
8414 static int perf_swevent_init(struct perf_event *event)
8415 {
8416 	u64 event_id = event->attr.config;
8417 
8418 	if (event->attr.type != PERF_TYPE_SOFTWARE)
8419 		return -ENOENT;
8420 
8421 	/*
8422 	 * no branch sampling for software events
8423 	 */
8424 	if (has_branch_stack(event))
8425 		return -EOPNOTSUPP;
8426 
8427 	switch (event_id) {
8428 	case PERF_COUNT_SW_CPU_CLOCK:
8429 	case PERF_COUNT_SW_TASK_CLOCK:
8430 		return -ENOENT;
8431 
8432 	default:
8433 		break;
8434 	}
8435 
8436 	if (event_id >= PERF_COUNT_SW_MAX)
8437 		return -ENOENT;
8438 
8439 	if (!event->parent) {
8440 		int err;
8441 
8442 		err = swevent_hlist_get();
8443 		if (err)
8444 			return err;
8445 
8446 		static_key_slow_inc(&perf_swevent_enabled[event_id]);
8447 		event->destroy = sw_perf_event_destroy;
8448 	}
8449 
8450 	return 0;
8451 }
8452 
8453 static struct pmu perf_swevent = {
8454 	.task_ctx_nr	= perf_sw_context,
8455 
8456 	.capabilities	= PERF_PMU_CAP_NO_NMI,
8457 
8458 	.event_init	= perf_swevent_init,
8459 	.add		= perf_swevent_add,
8460 	.del		= perf_swevent_del,
8461 	.start		= perf_swevent_start,
8462 	.stop		= perf_swevent_stop,
8463 	.read		= perf_swevent_read,
8464 };
8465 
8466 #ifdef CONFIG_EVENT_TRACING
8467 
8468 static int perf_tp_filter_match(struct perf_event *event,
8469 				struct perf_sample_data *data)
8470 {
8471 	void *record = data->raw->frag.data;
8472 
8473 	/* only top level events have filters set */
8474 	if (event->parent)
8475 		event = event->parent;
8476 
8477 	if (likely(!event->filter) || filter_match_preds(event->filter, record))
8478 		return 1;
8479 	return 0;
8480 }
8481 
8482 static int perf_tp_event_match(struct perf_event *event,
8483 				struct perf_sample_data *data,
8484 				struct pt_regs *regs)
8485 {
8486 	if (event->hw.state & PERF_HES_STOPPED)
8487 		return 0;
8488 	/*
8489 	 * All tracepoints are from kernel-space.
8490 	 */
8491 	if (event->attr.exclude_kernel)
8492 		return 0;
8493 
8494 	if (!perf_tp_filter_match(event, data))
8495 		return 0;
8496 
8497 	return 1;
8498 }
8499 
8500 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
8501 			       struct trace_event_call *call, u64 count,
8502 			       struct pt_regs *regs, struct hlist_head *head,
8503 			       struct task_struct *task)
8504 {
8505 	if (bpf_prog_array_valid(call)) {
8506 		*(struct pt_regs **)raw_data = regs;
8507 		if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
8508 			perf_swevent_put_recursion_context(rctx);
8509 			return;
8510 		}
8511 	}
8512 	perf_tp_event(call->event.type, count, raw_data, size, regs, head,
8513 		      rctx, task);
8514 }
8515 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
8516 
8517 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
8518 		   struct pt_regs *regs, struct hlist_head *head, int rctx,
8519 		   struct task_struct *task)
8520 {
8521 	struct perf_sample_data data;
8522 	struct perf_event *event;
8523 
8524 	struct perf_raw_record raw = {
8525 		.frag = {
8526 			.size = entry_size,
8527 			.data = record,
8528 		},
8529 	};
8530 
8531 	perf_sample_data_init(&data, 0, 0);
8532 	data.raw = &raw;
8533 
8534 	perf_trace_buf_update(record, event_type);
8535 
8536 	hlist_for_each_entry_rcu(event, head, hlist_entry) {
8537 		if (perf_tp_event_match(event, &data, regs))
8538 			perf_swevent_event(event, count, &data, regs);
8539 	}
8540 
8541 	/*
8542 	 * If we got specified a target task, also iterate its context and
8543 	 * deliver this event there too.
8544 	 */
8545 	if (task && task != current) {
8546 		struct perf_event_context *ctx;
8547 		struct trace_entry *entry = record;
8548 
8549 		rcu_read_lock();
8550 		ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8551 		if (!ctx)
8552 			goto unlock;
8553 
8554 		list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8555 			if (event->cpu != smp_processor_id())
8556 				continue;
8557 			if (event->attr.type != PERF_TYPE_TRACEPOINT)
8558 				continue;
8559 			if (event->attr.config != entry->type)
8560 				continue;
8561 			if (perf_tp_event_match(event, &data, regs))
8562 				perf_swevent_event(event, count, &data, regs);
8563 		}
8564 unlock:
8565 		rcu_read_unlock();
8566 	}
8567 
8568 	perf_swevent_put_recursion_context(rctx);
8569 }
8570 EXPORT_SYMBOL_GPL(perf_tp_event);
8571 
8572 static void tp_perf_event_destroy(struct perf_event *event)
8573 {
8574 	perf_trace_destroy(event);
8575 }
8576 
8577 static int perf_tp_event_init(struct perf_event *event)
8578 {
8579 	int err;
8580 
8581 	if (event->attr.type != PERF_TYPE_TRACEPOINT)
8582 		return -ENOENT;
8583 
8584 	/*
8585 	 * no branch sampling for tracepoint events
8586 	 */
8587 	if (has_branch_stack(event))
8588 		return -EOPNOTSUPP;
8589 
8590 	err = perf_trace_init(event);
8591 	if (err)
8592 		return err;
8593 
8594 	event->destroy = tp_perf_event_destroy;
8595 
8596 	return 0;
8597 }
8598 
8599 static struct pmu perf_tracepoint = {
8600 	.task_ctx_nr	= perf_sw_context,
8601 
8602 	.event_init	= perf_tp_event_init,
8603 	.add		= perf_trace_add,
8604 	.del		= perf_trace_del,
8605 	.start		= perf_swevent_start,
8606 	.stop		= perf_swevent_stop,
8607 	.read		= perf_swevent_read,
8608 };
8609 
8610 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
8611 /*
8612  * Flags in config, used by dynamic PMU kprobe and uprobe
8613  * The flags should match following PMU_FORMAT_ATTR().
8614  *
8615  * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
8616  *                               if not set, create kprobe/uprobe
8617  *
8618  * The following values specify a reference counter (or semaphore in the
8619  * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
8620  * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
8621  *
8622  * PERF_UPROBE_REF_CTR_OFFSET_BITS	# of bits in config as th offset
8623  * PERF_UPROBE_REF_CTR_OFFSET_SHIFT	# of bits to shift left
8624  */
8625 enum perf_probe_config {
8626 	PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0,  /* [k,u]retprobe */
8627 	PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
8628 	PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
8629 };
8630 
8631 PMU_FORMAT_ATTR(retprobe, "config:0");
8632 #endif
8633 
8634 #ifdef CONFIG_KPROBE_EVENTS
8635 static struct attribute *kprobe_attrs[] = {
8636 	&format_attr_retprobe.attr,
8637 	NULL,
8638 };
8639 
8640 static struct attribute_group kprobe_format_group = {
8641 	.name = "format",
8642 	.attrs = kprobe_attrs,
8643 };
8644 
8645 static const struct attribute_group *kprobe_attr_groups[] = {
8646 	&kprobe_format_group,
8647 	NULL,
8648 };
8649 
8650 static int perf_kprobe_event_init(struct perf_event *event);
8651 static struct pmu perf_kprobe = {
8652 	.task_ctx_nr	= perf_sw_context,
8653 	.event_init	= perf_kprobe_event_init,
8654 	.add		= perf_trace_add,
8655 	.del		= perf_trace_del,
8656 	.start		= perf_swevent_start,
8657 	.stop		= perf_swevent_stop,
8658 	.read		= perf_swevent_read,
8659 	.attr_groups	= kprobe_attr_groups,
8660 };
8661 
8662 static int perf_kprobe_event_init(struct perf_event *event)
8663 {
8664 	int err;
8665 	bool is_retprobe;
8666 
8667 	if (event->attr.type != perf_kprobe.type)
8668 		return -ENOENT;
8669 
8670 	if (!capable(CAP_SYS_ADMIN))
8671 		return -EACCES;
8672 
8673 	/*
8674 	 * no branch sampling for probe events
8675 	 */
8676 	if (has_branch_stack(event))
8677 		return -EOPNOTSUPP;
8678 
8679 	is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8680 	err = perf_kprobe_init(event, is_retprobe);
8681 	if (err)
8682 		return err;
8683 
8684 	event->destroy = perf_kprobe_destroy;
8685 
8686 	return 0;
8687 }
8688 #endif /* CONFIG_KPROBE_EVENTS */
8689 
8690 #ifdef CONFIG_UPROBE_EVENTS
8691 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
8692 
8693 static struct attribute *uprobe_attrs[] = {
8694 	&format_attr_retprobe.attr,
8695 	&format_attr_ref_ctr_offset.attr,
8696 	NULL,
8697 };
8698 
8699 static struct attribute_group uprobe_format_group = {
8700 	.name = "format",
8701 	.attrs = uprobe_attrs,
8702 };
8703 
8704 static const struct attribute_group *uprobe_attr_groups[] = {
8705 	&uprobe_format_group,
8706 	NULL,
8707 };
8708 
8709 static int perf_uprobe_event_init(struct perf_event *event);
8710 static struct pmu perf_uprobe = {
8711 	.task_ctx_nr	= perf_sw_context,
8712 	.event_init	= perf_uprobe_event_init,
8713 	.add		= perf_trace_add,
8714 	.del		= perf_trace_del,
8715 	.start		= perf_swevent_start,
8716 	.stop		= perf_swevent_stop,
8717 	.read		= perf_swevent_read,
8718 	.attr_groups	= uprobe_attr_groups,
8719 };
8720 
8721 static int perf_uprobe_event_init(struct perf_event *event)
8722 {
8723 	int err;
8724 	unsigned long ref_ctr_offset;
8725 	bool is_retprobe;
8726 
8727 	if (event->attr.type != perf_uprobe.type)
8728 		return -ENOENT;
8729 
8730 	if (!capable(CAP_SYS_ADMIN))
8731 		return -EACCES;
8732 
8733 	/*
8734 	 * no branch sampling for probe events
8735 	 */
8736 	if (has_branch_stack(event))
8737 		return -EOPNOTSUPP;
8738 
8739 	is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8740 	ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
8741 	err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
8742 	if (err)
8743 		return err;
8744 
8745 	event->destroy = perf_uprobe_destroy;
8746 
8747 	return 0;
8748 }
8749 #endif /* CONFIG_UPROBE_EVENTS */
8750 
8751 static inline void perf_tp_register(void)
8752 {
8753 	perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8754 #ifdef CONFIG_KPROBE_EVENTS
8755 	perf_pmu_register(&perf_kprobe, "kprobe", -1);
8756 #endif
8757 #ifdef CONFIG_UPROBE_EVENTS
8758 	perf_pmu_register(&perf_uprobe, "uprobe", -1);
8759 #endif
8760 }
8761 
8762 static void perf_event_free_filter(struct perf_event *event)
8763 {
8764 	ftrace_profile_free_filter(event);
8765 }
8766 
8767 #ifdef CONFIG_BPF_SYSCALL
8768 static void bpf_overflow_handler(struct perf_event *event,
8769 				 struct perf_sample_data *data,
8770 				 struct pt_regs *regs)
8771 {
8772 	struct bpf_perf_event_data_kern ctx = {
8773 		.data = data,
8774 		.event = event,
8775 	};
8776 	int ret = 0;
8777 
8778 	ctx.regs = perf_arch_bpf_user_pt_regs(regs);
8779 	preempt_disable();
8780 	if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8781 		goto out;
8782 	rcu_read_lock();
8783 	ret = BPF_PROG_RUN(event->prog, &ctx);
8784 	rcu_read_unlock();
8785 out:
8786 	__this_cpu_dec(bpf_prog_active);
8787 	preempt_enable();
8788 	if (!ret)
8789 		return;
8790 
8791 	event->orig_overflow_handler(event, data, regs);
8792 }
8793 
8794 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8795 {
8796 	struct bpf_prog *prog;
8797 
8798 	if (event->overflow_handler_context)
8799 		/* hw breakpoint or kernel counter */
8800 		return -EINVAL;
8801 
8802 	if (event->prog)
8803 		return -EEXIST;
8804 
8805 	prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8806 	if (IS_ERR(prog))
8807 		return PTR_ERR(prog);
8808 
8809 	event->prog = prog;
8810 	event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8811 	WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8812 	return 0;
8813 }
8814 
8815 static void perf_event_free_bpf_handler(struct perf_event *event)
8816 {
8817 	struct bpf_prog *prog = event->prog;
8818 
8819 	if (!prog)
8820 		return;
8821 
8822 	WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8823 	event->prog = NULL;
8824 	bpf_prog_put(prog);
8825 }
8826 #else
8827 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8828 {
8829 	return -EOPNOTSUPP;
8830 }
8831 static void perf_event_free_bpf_handler(struct perf_event *event)
8832 {
8833 }
8834 #endif
8835 
8836 /*
8837  * returns true if the event is a tracepoint, or a kprobe/upprobe created
8838  * with perf_event_open()
8839  */
8840 static inline bool perf_event_is_tracing(struct perf_event *event)
8841 {
8842 	if (event->pmu == &perf_tracepoint)
8843 		return true;
8844 #ifdef CONFIG_KPROBE_EVENTS
8845 	if (event->pmu == &perf_kprobe)
8846 		return true;
8847 #endif
8848 #ifdef CONFIG_UPROBE_EVENTS
8849 	if (event->pmu == &perf_uprobe)
8850 		return true;
8851 #endif
8852 	return false;
8853 }
8854 
8855 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8856 {
8857 	bool is_kprobe, is_tracepoint, is_syscall_tp;
8858 	struct bpf_prog *prog;
8859 	int ret;
8860 
8861 	if (!perf_event_is_tracing(event))
8862 		return perf_event_set_bpf_handler(event, prog_fd);
8863 
8864 	is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8865 	is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8866 	is_syscall_tp = is_syscall_trace_event(event->tp_event);
8867 	if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
8868 		/* bpf programs can only be attached to u/kprobe or tracepoint */
8869 		return -EINVAL;
8870 
8871 	prog = bpf_prog_get(prog_fd);
8872 	if (IS_ERR(prog))
8873 		return PTR_ERR(prog);
8874 
8875 	if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8876 	    (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
8877 	    (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8878 		/* valid fd, but invalid bpf program type */
8879 		bpf_prog_put(prog);
8880 		return -EINVAL;
8881 	}
8882 
8883 	/* Kprobe override only works for kprobes, not uprobes. */
8884 	if (prog->kprobe_override &&
8885 	    !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
8886 		bpf_prog_put(prog);
8887 		return -EINVAL;
8888 	}
8889 
8890 	if (is_tracepoint || is_syscall_tp) {
8891 		int off = trace_event_get_offsets(event->tp_event);
8892 
8893 		if (prog->aux->max_ctx_offset > off) {
8894 			bpf_prog_put(prog);
8895 			return -EACCES;
8896 		}
8897 	}
8898 
8899 	ret = perf_event_attach_bpf_prog(event, prog);
8900 	if (ret)
8901 		bpf_prog_put(prog);
8902 	return ret;
8903 }
8904 
8905 static void perf_event_free_bpf_prog(struct perf_event *event)
8906 {
8907 	if (!perf_event_is_tracing(event)) {
8908 		perf_event_free_bpf_handler(event);
8909 		return;
8910 	}
8911 	perf_event_detach_bpf_prog(event);
8912 }
8913 
8914 #else
8915 
8916 static inline void perf_tp_register(void)
8917 {
8918 }
8919 
8920 static void perf_event_free_filter(struct perf_event *event)
8921 {
8922 }
8923 
8924 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8925 {
8926 	return -ENOENT;
8927 }
8928 
8929 static void perf_event_free_bpf_prog(struct perf_event *event)
8930 {
8931 }
8932 #endif /* CONFIG_EVENT_TRACING */
8933 
8934 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8935 void perf_bp_event(struct perf_event *bp, void *data)
8936 {
8937 	struct perf_sample_data sample;
8938 	struct pt_regs *regs = data;
8939 
8940 	perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8941 
8942 	if (!bp->hw.state && !perf_exclude_event(bp, regs))
8943 		perf_swevent_event(bp, 1, &sample, regs);
8944 }
8945 #endif
8946 
8947 /*
8948  * Allocate a new address filter
8949  */
8950 static struct perf_addr_filter *
8951 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8952 {
8953 	int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8954 	struct perf_addr_filter *filter;
8955 
8956 	filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8957 	if (!filter)
8958 		return NULL;
8959 
8960 	INIT_LIST_HEAD(&filter->entry);
8961 	list_add_tail(&filter->entry, filters);
8962 
8963 	return filter;
8964 }
8965 
8966 static void free_filters_list(struct list_head *filters)
8967 {
8968 	struct perf_addr_filter *filter, *iter;
8969 
8970 	list_for_each_entry_safe(filter, iter, filters, entry) {
8971 		path_put(&filter->path);
8972 		list_del(&filter->entry);
8973 		kfree(filter);
8974 	}
8975 }
8976 
8977 /*
8978  * Free existing address filters and optionally install new ones
8979  */
8980 static void perf_addr_filters_splice(struct perf_event *event,
8981 				     struct list_head *head)
8982 {
8983 	unsigned long flags;
8984 	LIST_HEAD(list);
8985 
8986 	if (!has_addr_filter(event))
8987 		return;
8988 
8989 	/* don't bother with children, they don't have their own filters */
8990 	if (event->parent)
8991 		return;
8992 
8993 	raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8994 
8995 	list_splice_init(&event->addr_filters.list, &list);
8996 	if (head)
8997 		list_splice(head, &event->addr_filters.list);
8998 
8999 	raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
9000 
9001 	free_filters_list(&list);
9002 }
9003 
9004 /*
9005  * Scan through mm's vmas and see if one of them matches the
9006  * @filter; if so, adjust filter's address range.
9007  * Called with mm::mmap_sem down for reading.
9008  */
9009 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
9010 				   struct mm_struct *mm,
9011 				   struct perf_addr_filter_range *fr)
9012 {
9013 	struct vm_area_struct *vma;
9014 
9015 	for (vma = mm->mmap; vma; vma = vma->vm_next) {
9016 		if (!vma->vm_file)
9017 			continue;
9018 
9019 		if (perf_addr_filter_vma_adjust(filter, vma, fr))
9020 			return;
9021 	}
9022 }
9023 
9024 /*
9025  * Update event's address range filters based on the
9026  * task's existing mappings, if any.
9027  */
9028 static void perf_event_addr_filters_apply(struct perf_event *event)
9029 {
9030 	struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
9031 	struct task_struct *task = READ_ONCE(event->ctx->task);
9032 	struct perf_addr_filter *filter;
9033 	struct mm_struct *mm = NULL;
9034 	unsigned int count = 0;
9035 	unsigned long flags;
9036 
9037 	/*
9038 	 * We may observe TASK_TOMBSTONE, which means that the event tear-down
9039 	 * will stop on the parent's child_mutex that our caller is also holding
9040 	 */
9041 	if (task == TASK_TOMBSTONE)
9042 		return;
9043 
9044 	if (!ifh->nr_file_filters)
9045 		return;
9046 
9047 	mm = get_task_mm(event->ctx->task);
9048 	if (!mm)
9049 		goto restart;
9050 
9051 	down_read(&mm->mmap_sem);
9052 
9053 	raw_spin_lock_irqsave(&ifh->lock, flags);
9054 	list_for_each_entry(filter, &ifh->list, entry) {
9055 		event->addr_filter_ranges[count].start = 0;
9056 		event->addr_filter_ranges[count].size = 0;
9057 
9058 		/*
9059 		 * Adjust base offset if the filter is associated to a binary
9060 		 * that needs to be mapped:
9061 		 */
9062 		if (filter->path.dentry)
9063 			perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
9064 
9065 		count++;
9066 	}
9067 
9068 	event->addr_filters_gen++;
9069 	raw_spin_unlock_irqrestore(&ifh->lock, flags);
9070 
9071 	up_read(&mm->mmap_sem);
9072 
9073 	mmput(mm);
9074 
9075 restart:
9076 	perf_event_stop(event, 1);
9077 }
9078 
9079 /*
9080  * Address range filtering: limiting the data to certain
9081  * instruction address ranges. Filters are ioctl()ed to us from
9082  * userspace as ascii strings.
9083  *
9084  * Filter string format:
9085  *
9086  * ACTION RANGE_SPEC
9087  * where ACTION is one of the
9088  *  * "filter": limit the trace to this region
9089  *  * "start": start tracing from this address
9090  *  * "stop": stop tracing at this address/region;
9091  * RANGE_SPEC is
9092  *  * for kernel addresses: <start address>[/<size>]
9093  *  * for object files:     <start address>[/<size>]@</path/to/object/file>
9094  *
9095  * if <size> is not specified or is zero, the range is treated as a single
9096  * address; not valid for ACTION=="filter".
9097  */
9098 enum {
9099 	IF_ACT_NONE = -1,
9100 	IF_ACT_FILTER,
9101 	IF_ACT_START,
9102 	IF_ACT_STOP,
9103 	IF_SRC_FILE,
9104 	IF_SRC_KERNEL,
9105 	IF_SRC_FILEADDR,
9106 	IF_SRC_KERNELADDR,
9107 };
9108 
9109 enum {
9110 	IF_STATE_ACTION = 0,
9111 	IF_STATE_SOURCE,
9112 	IF_STATE_END,
9113 };
9114 
9115 static const match_table_t if_tokens = {
9116 	{ IF_ACT_FILTER,	"filter" },
9117 	{ IF_ACT_START,		"start" },
9118 	{ IF_ACT_STOP,		"stop" },
9119 	{ IF_SRC_FILE,		"%u/%u@%s" },
9120 	{ IF_SRC_KERNEL,	"%u/%u" },
9121 	{ IF_SRC_FILEADDR,	"%u@%s" },
9122 	{ IF_SRC_KERNELADDR,	"%u" },
9123 	{ IF_ACT_NONE,		NULL },
9124 };
9125 
9126 /*
9127  * Address filter string parser
9128  */
9129 static int
9130 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
9131 			     struct list_head *filters)
9132 {
9133 	struct perf_addr_filter *filter = NULL;
9134 	char *start, *orig, *filename = NULL;
9135 	substring_t args[MAX_OPT_ARGS];
9136 	int state = IF_STATE_ACTION, token;
9137 	unsigned int kernel = 0;
9138 	int ret = -EINVAL;
9139 
9140 	orig = fstr = kstrdup(fstr, GFP_KERNEL);
9141 	if (!fstr)
9142 		return -ENOMEM;
9143 
9144 	while ((start = strsep(&fstr, " ,\n")) != NULL) {
9145 		static const enum perf_addr_filter_action_t actions[] = {
9146 			[IF_ACT_FILTER]	= PERF_ADDR_FILTER_ACTION_FILTER,
9147 			[IF_ACT_START]	= PERF_ADDR_FILTER_ACTION_START,
9148 			[IF_ACT_STOP]	= PERF_ADDR_FILTER_ACTION_STOP,
9149 		};
9150 		ret = -EINVAL;
9151 
9152 		if (!*start)
9153 			continue;
9154 
9155 		/* filter definition begins */
9156 		if (state == IF_STATE_ACTION) {
9157 			filter = perf_addr_filter_new(event, filters);
9158 			if (!filter)
9159 				goto fail;
9160 		}
9161 
9162 		token = match_token(start, if_tokens, args);
9163 		switch (token) {
9164 		case IF_ACT_FILTER:
9165 		case IF_ACT_START:
9166 		case IF_ACT_STOP:
9167 			if (state != IF_STATE_ACTION)
9168 				goto fail;
9169 
9170 			filter->action = actions[token];
9171 			state = IF_STATE_SOURCE;
9172 			break;
9173 
9174 		case IF_SRC_KERNELADDR:
9175 		case IF_SRC_KERNEL:
9176 			kernel = 1;
9177 
9178 		case IF_SRC_FILEADDR:
9179 		case IF_SRC_FILE:
9180 			if (state != IF_STATE_SOURCE)
9181 				goto fail;
9182 
9183 			*args[0].to = 0;
9184 			ret = kstrtoul(args[0].from, 0, &filter->offset);
9185 			if (ret)
9186 				goto fail;
9187 
9188 			if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
9189 				*args[1].to = 0;
9190 				ret = kstrtoul(args[1].from, 0, &filter->size);
9191 				if (ret)
9192 					goto fail;
9193 			}
9194 
9195 			if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
9196 				int fpos = token == IF_SRC_FILE ? 2 : 1;
9197 
9198 				filename = match_strdup(&args[fpos]);
9199 				if (!filename) {
9200 					ret = -ENOMEM;
9201 					goto fail;
9202 				}
9203 			}
9204 
9205 			state = IF_STATE_END;
9206 			break;
9207 
9208 		default:
9209 			goto fail;
9210 		}
9211 
9212 		/*
9213 		 * Filter definition is fully parsed, validate and install it.
9214 		 * Make sure that it doesn't contradict itself or the event's
9215 		 * attribute.
9216 		 */
9217 		if (state == IF_STATE_END) {
9218 			ret = -EINVAL;
9219 			if (kernel && event->attr.exclude_kernel)
9220 				goto fail;
9221 
9222 			/*
9223 			 * ACTION "filter" must have a non-zero length region
9224 			 * specified.
9225 			 */
9226 			if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
9227 			    !filter->size)
9228 				goto fail;
9229 
9230 			if (!kernel) {
9231 				if (!filename)
9232 					goto fail;
9233 
9234 				/*
9235 				 * For now, we only support file-based filters
9236 				 * in per-task events; doing so for CPU-wide
9237 				 * events requires additional context switching
9238 				 * trickery, since same object code will be
9239 				 * mapped at different virtual addresses in
9240 				 * different processes.
9241 				 */
9242 				ret = -EOPNOTSUPP;
9243 				if (!event->ctx->task)
9244 					goto fail_free_name;
9245 
9246 				/* look up the path and grab its inode */
9247 				ret = kern_path(filename, LOOKUP_FOLLOW,
9248 						&filter->path);
9249 				if (ret)
9250 					goto fail_free_name;
9251 
9252 				kfree(filename);
9253 				filename = NULL;
9254 
9255 				ret = -EINVAL;
9256 				if (!filter->path.dentry ||
9257 				    !S_ISREG(d_inode(filter->path.dentry)
9258 					     ->i_mode))
9259 					goto fail;
9260 
9261 				event->addr_filters.nr_file_filters++;
9262 			}
9263 
9264 			/* ready to consume more filters */
9265 			state = IF_STATE_ACTION;
9266 			filter = NULL;
9267 		}
9268 	}
9269 
9270 	if (state != IF_STATE_ACTION)
9271 		goto fail;
9272 
9273 	kfree(orig);
9274 
9275 	return 0;
9276 
9277 fail_free_name:
9278 	kfree(filename);
9279 fail:
9280 	free_filters_list(filters);
9281 	kfree(orig);
9282 
9283 	return ret;
9284 }
9285 
9286 static int
9287 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
9288 {
9289 	LIST_HEAD(filters);
9290 	int ret;
9291 
9292 	/*
9293 	 * Since this is called in perf_ioctl() path, we're already holding
9294 	 * ctx::mutex.
9295 	 */
9296 	lockdep_assert_held(&event->ctx->mutex);
9297 
9298 	if (WARN_ON_ONCE(event->parent))
9299 		return -EINVAL;
9300 
9301 	ret = perf_event_parse_addr_filter(event, filter_str, &filters);
9302 	if (ret)
9303 		goto fail_clear_files;
9304 
9305 	ret = event->pmu->addr_filters_validate(&filters);
9306 	if (ret)
9307 		goto fail_free_filters;
9308 
9309 	/* remove existing filters, if any */
9310 	perf_addr_filters_splice(event, &filters);
9311 
9312 	/* install new filters */
9313 	perf_event_for_each_child(event, perf_event_addr_filters_apply);
9314 
9315 	return ret;
9316 
9317 fail_free_filters:
9318 	free_filters_list(&filters);
9319 
9320 fail_clear_files:
9321 	event->addr_filters.nr_file_filters = 0;
9322 
9323 	return ret;
9324 }
9325 
9326 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
9327 {
9328 	int ret = -EINVAL;
9329 	char *filter_str;
9330 
9331 	filter_str = strndup_user(arg, PAGE_SIZE);
9332 	if (IS_ERR(filter_str))
9333 		return PTR_ERR(filter_str);
9334 
9335 #ifdef CONFIG_EVENT_TRACING
9336 	if (perf_event_is_tracing(event)) {
9337 		struct perf_event_context *ctx = event->ctx;
9338 
9339 		/*
9340 		 * Beware, here be dragons!!
9341 		 *
9342 		 * the tracepoint muck will deadlock against ctx->mutex, but
9343 		 * the tracepoint stuff does not actually need it. So
9344 		 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
9345 		 * already have a reference on ctx.
9346 		 *
9347 		 * This can result in event getting moved to a different ctx,
9348 		 * but that does not affect the tracepoint state.
9349 		 */
9350 		mutex_unlock(&ctx->mutex);
9351 		ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
9352 		mutex_lock(&ctx->mutex);
9353 	} else
9354 #endif
9355 	if (has_addr_filter(event))
9356 		ret = perf_event_set_addr_filter(event, filter_str);
9357 
9358 	kfree(filter_str);
9359 	return ret;
9360 }
9361 
9362 /*
9363  * hrtimer based swevent callback
9364  */
9365 
9366 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
9367 {
9368 	enum hrtimer_restart ret = HRTIMER_RESTART;
9369 	struct perf_sample_data data;
9370 	struct pt_regs *regs;
9371 	struct perf_event *event;
9372 	u64 period;
9373 
9374 	event = container_of(hrtimer, struct perf_event, hw.hrtimer);
9375 
9376 	if (event->state != PERF_EVENT_STATE_ACTIVE)
9377 		return HRTIMER_NORESTART;
9378 
9379 	event->pmu->read(event);
9380 
9381 	perf_sample_data_init(&data, 0, event->hw.last_period);
9382 	regs = get_irq_regs();
9383 
9384 	if (regs && !perf_exclude_event(event, regs)) {
9385 		if (!(event->attr.exclude_idle && is_idle_task(current)))
9386 			if (__perf_event_overflow(event, 1, &data, regs))
9387 				ret = HRTIMER_NORESTART;
9388 	}
9389 
9390 	period = max_t(u64, 10000, event->hw.sample_period);
9391 	hrtimer_forward_now(hrtimer, ns_to_ktime(period));
9392 
9393 	return ret;
9394 }
9395 
9396 static void perf_swevent_start_hrtimer(struct perf_event *event)
9397 {
9398 	struct hw_perf_event *hwc = &event->hw;
9399 	s64 period;
9400 
9401 	if (!is_sampling_event(event))
9402 		return;
9403 
9404 	period = local64_read(&hwc->period_left);
9405 	if (period) {
9406 		if (period < 0)
9407 			period = 10000;
9408 
9409 		local64_set(&hwc->period_left, 0);
9410 	} else {
9411 		period = max_t(u64, 10000, hwc->sample_period);
9412 	}
9413 	hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
9414 		      HRTIMER_MODE_REL_PINNED);
9415 }
9416 
9417 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
9418 {
9419 	struct hw_perf_event *hwc = &event->hw;
9420 
9421 	if (is_sampling_event(event)) {
9422 		ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
9423 		local64_set(&hwc->period_left, ktime_to_ns(remaining));
9424 
9425 		hrtimer_cancel(&hwc->hrtimer);
9426 	}
9427 }
9428 
9429 static void perf_swevent_init_hrtimer(struct perf_event *event)
9430 {
9431 	struct hw_perf_event *hwc = &event->hw;
9432 
9433 	if (!is_sampling_event(event))
9434 		return;
9435 
9436 	hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
9437 	hwc->hrtimer.function = perf_swevent_hrtimer;
9438 
9439 	/*
9440 	 * Since hrtimers have a fixed rate, we can do a static freq->period
9441 	 * mapping and avoid the whole period adjust feedback stuff.
9442 	 */
9443 	if (event->attr.freq) {
9444 		long freq = event->attr.sample_freq;
9445 
9446 		event->attr.sample_period = NSEC_PER_SEC / freq;
9447 		hwc->sample_period = event->attr.sample_period;
9448 		local64_set(&hwc->period_left, hwc->sample_period);
9449 		hwc->last_period = hwc->sample_period;
9450 		event->attr.freq = 0;
9451 	}
9452 }
9453 
9454 /*
9455  * Software event: cpu wall time clock
9456  */
9457 
9458 static void cpu_clock_event_update(struct perf_event *event)
9459 {
9460 	s64 prev;
9461 	u64 now;
9462 
9463 	now = local_clock();
9464 	prev = local64_xchg(&event->hw.prev_count, now);
9465 	local64_add(now - prev, &event->count);
9466 }
9467 
9468 static void cpu_clock_event_start(struct perf_event *event, int flags)
9469 {
9470 	local64_set(&event->hw.prev_count, local_clock());
9471 	perf_swevent_start_hrtimer(event);
9472 }
9473 
9474 static void cpu_clock_event_stop(struct perf_event *event, int flags)
9475 {
9476 	perf_swevent_cancel_hrtimer(event);
9477 	cpu_clock_event_update(event);
9478 }
9479 
9480 static int cpu_clock_event_add(struct perf_event *event, int flags)
9481 {
9482 	if (flags & PERF_EF_START)
9483 		cpu_clock_event_start(event, flags);
9484 	perf_event_update_userpage(event);
9485 
9486 	return 0;
9487 }
9488 
9489 static void cpu_clock_event_del(struct perf_event *event, int flags)
9490 {
9491 	cpu_clock_event_stop(event, flags);
9492 }
9493 
9494 static void cpu_clock_event_read(struct perf_event *event)
9495 {
9496 	cpu_clock_event_update(event);
9497 }
9498 
9499 static int cpu_clock_event_init(struct perf_event *event)
9500 {
9501 	if (event->attr.type != PERF_TYPE_SOFTWARE)
9502 		return -ENOENT;
9503 
9504 	if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
9505 		return -ENOENT;
9506 
9507 	/*
9508 	 * no branch sampling for software events
9509 	 */
9510 	if (has_branch_stack(event))
9511 		return -EOPNOTSUPP;
9512 
9513 	perf_swevent_init_hrtimer(event);
9514 
9515 	return 0;
9516 }
9517 
9518 static struct pmu perf_cpu_clock = {
9519 	.task_ctx_nr	= perf_sw_context,
9520 
9521 	.capabilities	= PERF_PMU_CAP_NO_NMI,
9522 
9523 	.event_init	= cpu_clock_event_init,
9524 	.add		= cpu_clock_event_add,
9525 	.del		= cpu_clock_event_del,
9526 	.start		= cpu_clock_event_start,
9527 	.stop		= cpu_clock_event_stop,
9528 	.read		= cpu_clock_event_read,
9529 };
9530 
9531 /*
9532  * Software event: task time clock
9533  */
9534 
9535 static void task_clock_event_update(struct perf_event *event, u64 now)
9536 {
9537 	u64 prev;
9538 	s64 delta;
9539 
9540 	prev = local64_xchg(&event->hw.prev_count, now);
9541 	delta = now - prev;
9542 	local64_add(delta, &event->count);
9543 }
9544 
9545 static void task_clock_event_start(struct perf_event *event, int flags)
9546 {
9547 	local64_set(&event->hw.prev_count, event->ctx->time);
9548 	perf_swevent_start_hrtimer(event);
9549 }
9550 
9551 static void task_clock_event_stop(struct perf_event *event, int flags)
9552 {
9553 	perf_swevent_cancel_hrtimer(event);
9554 	task_clock_event_update(event, event->ctx->time);
9555 }
9556 
9557 static int task_clock_event_add(struct perf_event *event, int flags)
9558 {
9559 	if (flags & PERF_EF_START)
9560 		task_clock_event_start(event, flags);
9561 	perf_event_update_userpage(event);
9562 
9563 	return 0;
9564 }
9565 
9566 static void task_clock_event_del(struct perf_event *event, int flags)
9567 {
9568 	task_clock_event_stop(event, PERF_EF_UPDATE);
9569 }
9570 
9571 static void task_clock_event_read(struct perf_event *event)
9572 {
9573 	u64 now = perf_clock();
9574 	u64 delta = now - event->ctx->timestamp;
9575 	u64 time = event->ctx->time + delta;
9576 
9577 	task_clock_event_update(event, time);
9578 }
9579 
9580 static int task_clock_event_init(struct perf_event *event)
9581 {
9582 	if (event->attr.type != PERF_TYPE_SOFTWARE)
9583 		return -ENOENT;
9584 
9585 	if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
9586 		return -ENOENT;
9587 
9588 	/*
9589 	 * no branch sampling for software events
9590 	 */
9591 	if (has_branch_stack(event))
9592 		return -EOPNOTSUPP;
9593 
9594 	perf_swevent_init_hrtimer(event);
9595 
9596 	return 0;
9597 }
9598 
9599 static struct pmu perf_task_clock = {
9600 	.task_ctx_nr	= perf_sw_context,
9601 
9602 	.capabilities	= PERF_PMU_CAP_NO_NMI,
9603 
9604 	.event_init	= task_clock_event_init,
9605 	.add		= task_clock_event_add,
9606 	.del		= task_clock_event_del,
9607 	.start		= task_clock_event_start,
9608 	.stop		= task_clock_event_stop,
9609 	.read		= task_clock_event_read,
9610 };
9611 
9612 static void perf_pmu_nop_void(struct pmu *pmu)
9613 {
9614 }
9615 
9616 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
9617 {
9618 }
9619 
9620 static int perf_pmu_nop_int(struct pmu *pmu)
9621 {
9622 	return 0;
9623 }
9624 
9625 static int perf_event_nop_int(struct perf_event *event, u64 value)
9626 {
9627 	return 0;
9628 }
9629 
9630 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
9631 
9632 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
9633 {
9634 	__this_cpu_write(nop_txn_flags, flags);
9635 
9636 	if (flags & ~PERF_PMU_TXN_ADD)
9637 		return;
9638 
9639 	perf_pmu_disable(pmu);
9640 }
9641 
9642 static int perf_pmu_commit_txn(struct pmu *pmu)
9643 {
9644 	unsigned int flags = __this_cpu_read(nop_txn_flags);
9645 
9646 	__this_cpu_write(nop_txn_flags, 0);
9647 
9648 	if (flags & ~PERF_PMU_TXN_ADD)
9649 		return 0;
9650 
9651 	perf_pmu_enable(pmu);
9652 	return 0;
9653 }
9654 
9655 static void perf_pmu_cancel_txn(struct pmu *pmu)
9656 {
9657 	unsigned int flags =  __this_cpu_read(nop_txn_flags);
9658 
9659 	__this_cpu_write(nop_txn_flags, 0);
9660 
9661 	if (flags & ~PERF_PMU_TXN_ADD)
9662 		return;
9663 
9664 	perf_pmu_enable(pmu);
9665 }
9666 
9667 static int perf_event_idx_default(struct perf_event *event)
9668 {
9669 	return 0;
9670 }
9671 
9672 /*
9673  * Ensures all contexts with the same task_ctx_nr have the same
9674  * pmu_cpu_context too.
9675  */
9676 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
9677 {
9678 	struct pmu *pmu;
9679 
9680 	if (ctxn < 0)
9681 		return NULL;
9682 
9683 	list_for_each_entry(pmu, &pmus, entry) {
9684 		if (pmu->task_ctx_nr == ctxn)
9685 			return pmu->pmu_cpu_context;
9686 	}
9687 
9688 	return NULL;
9689 }
9690 
9691 static void free_pmu_context(struct pmu *pmu)
9692 {
9693 	/*
9694 	 * Static contexts such as perf_sw_context have a global lifetime
9695 	 * and may be shared between different PMUs. Avoid freeing them
9696 	 * when a single PMU is going away.
9697 	 */
9698 	if (pmu->task_ctx_nr > perf_invalid_context)
9699 		return;
9700 
9701 	free_percpu(pmu->pmu_cpu_context);
9702 }
9703 
9704 /*
9705  * Let userspace know that this PMU supports address range filtering:
9706  */
9707 static ssize_t nr_addr_filters_show(struct device *dev,
9708 				    struct device_attribute *attr,
9709 				    char *page)
9710 {
9711 	struct pmu *pmu = dev_get_drvdata(dev);
9712 
9713 	return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
9714 }
9715 DEVICE_ATTR_RO(nr_addr_filters);
9716 
9717 static struct idr pmu_idr;
9718 
9719 static ssize_t
9720 type_show(struct device *dev, struct device_attribute *attr, char *page)
9721 {
9722 	struct pmu *pmu = dev_get_drvdata(dev);
9723 
9724 	return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
9725 }
9726 static DEVICE_ATTR_RO(type);
9727 
9728 static ssize_t
9729 perf_event_mux_interval_ms_show(struct device *dev,
9730 				struct device_attribute *attr,
9731 				char *page)
9732 {
9733 	struct pmu *pmu = dev_get_drvdata(dev);
9734 
9735 	return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
9736 }
9737 
9738 static DEFINE_MUTEX(mux_interval_mutex);
9739 
9740 static ssize_t
9741 perf_event_mux_interval_ms_store(struct device *dev,
9742 				 struct device_attribute *attr,
9743 				 const char *buf, size_t count)
9744 {
9745 	struct pmu *pmu = dev_get_drvdata(dev);
9746 	int timer, cpu, ret;
9747 
9748 	ret = kstrtoint(buf, 0, &timer);
9749 	if (ret)
9750 		return ret;
9751 
9752 	if (timer < 1)
9753 		return -EINVAL;
9754 
9755 	/* same value, noting to do */
9756 	if (timer == pmu->hrtimer_interval_ms)
9757 		return count;
9758 
9759 	mutex_lock(&mux_interval_mutex);
9760 	pmu->hrtimer_interval_ms = timer;
9761 
9762 	/* update all cpuctx for this PMU */
9763 	cpus_read_lock();
9764 	for_each_online_cpu(cpu) {
9765 		struct perf_cpu_context *cpuctx;
9766 		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9767 		cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9768 
9769 		cpu_function_call(cpu,
9770 			(remote_function_f)perf_mux_hrtimer_restart, cpuctx);
9771 	}
9772 	cpus_read_unlock();
9773 	mutex_unlock(&mux_interval_mutex);
9774 
9775 	return count;
9776 }
9777 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9778 
9779 static struct attribute *pmu_dev_attrs[] = {
9780 	&dev_attr_type.attr,
9781 	&dev_attr_perf_event_mux_interval_ms.attr,
9782 	NULL,
9783 };
9784 ATTRIBUTE_GROUPS(pmu_dev);
9785 
9786 static int pmu_bus_running;
9787 static struct bus_type pmu_bus = {
9788 	.name		= "event_source",
9789 	.dev_groups	= pmu_dev_groups,
9790 };
9791 
9792 static void pmu_dev_release(struct device *dev)
9793 {
9794 	kfree(dev);
9795 }
9796 
9797 static int pmu_dev_alloc(struct pmu *pmu)
9798 {
9799 	int ret = -ENOMEM;
9800 
9801 	pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9802 	if (!pmu->dev)
9803 		goto out;
9804 
9805 	pmu->dev->groups = pmu->attr_groups;
9806 	device_initialize(pmu->dev);
9807 	ret = dev_set_name(pmu->dev, "%s", pmu->name);
9808 	if (ret)
9809 		goto free_dev;
9810 
9811 	dev_set_drvdata(pmu->dev, pmu);
9812 	pmu->dev->bus = &pmu_bus;
9813 	pmu->dev->release = pmu_dev_release;
9814 	ret = device_add(pmu->dev);
9815 	if (ret)
9816 		goto free_dev;
9817 
9818 	/* For PMUs with address filters, throw in an extra attribute: */
9819 	if (pmu->nr_addr_filters)
9820 		ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9821 
9822 	if (ret)
9823 		goto del_dev;
9824 
9825 out:
9826 	return ret;
9827 
9828 del_dev:
9829 	device_del(pmu->dev);
9830 
9831 free_dev:
9832 	put_device(pmu->dev);
9833 	goto out;
9834 }
9835 
9836 static struct lock_class_key cpuctx_mutex;
9837 static struct lock_class_key cpuctx_lock;
9838 
9839 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9840 {
9841 	int cpu, ret;
9842 
9843 	mutex_lock(&pmus_lock);
9844 	ret = -ENOMEM;
9845 	pmu->pmu_disable_count = alloc_percpu(int);
9846 	if (!pmu->pmu_disable_count)
9847 		goto unlock;
9848 
9849 	pmu->type = -1;
9850 	if (!name)
9851 		goto skip_type;
9852 	pmu->name = name;
9853 
9854 	if (type < 0) {
9855 		type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9856 		if (type < 0) {
9857 			ret = type;
9858 			goto free_pdc;
9859 		}
9860 	}
9861 	pmu->type = type;
9862 
9863 	if (pmu_bus_running) {
9864 		ret = pmu_dev_alloc(pmu);
9865 		if (ret)
9866 			goto free_idr;
9867 	}
9868 
9869 skip_type:
9870 	if (pmu->task_ctx_nr == perf_hw_context) {
9871 		static int hw_context_taken = 0;
9872 
9873 		/*
9874 		 * Other than systems with heterogeneous CPUs, it never makes
9875 		 * sense for two PMUs to share perf_hw_context. PMUs which are
9876 		 * uncore must use perf_invalid_context.
9877 		 */
9878 		if (WARN_ON_ONCE(hw_context_taken &&
9879 		    !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9880 			pmu->task_ctx_nr = perf_invalid_context;
9881 
9882 		hw_context_taken = 1;
9883 	}
9884 
9885 	pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9886 	if (pmu->pmu_cpu_context)
9887 		goto got_cpu_context;
9888 
9889 	ret = -ENOMEM;
9890 	pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9891 	if (!pmu->pmu_cpu_context)
9892 		goto free_dev;
9893 
9894 	for_each_possible_cpu(cpu) {
9895 		struct perf_cpu_context *cpuctx;
9896 
9897 		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9898 		__perf_event_init_context(&cpuctx->ctx);
9899 		lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9900 		lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9901 		cpuctx->ctx.pmu = pmu;
9902 		cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9903 
9904 		__perf_mux_hrtimer_init(cpuctx, cpu);
9905 	}
9906 
9907 got_cpu_context:
9908 	if (!pmu->start_txn) {
9909 		if (pmu->pmu_enable) {
9910 			/*
9911 			 * If we have pmu_enable/pmu_disable calls, install
9912 			 * transaction stubs that use that to try and batch
9913 			 * hardware accesses.
9914 			 */
9915 			pmu->start_txn  = perf_pmu_start_txn;
9916 			pmu->commit_txn = perf_pmu_commit_txn;
9917 			pmu->cancel_txn = perf_pmu_cancel_txn;
9918 		} else {
9919 			pmu->start_txn  = perf_pmu_nop_txn;
9920 			pmu->commit_txn = perf_pmu_nop_int;
9921 			pmu->cancel_txn = perf_pmu_nop_void;
9922 		}
9923 	}
9924 
9925 	if (!pmu->pmu_enable) {
9926 		pmu->pmu_enable  = perf_pmu_nop_void;
9927 		pmu->pmu_disable = perf_pmu_nop_void;
9928 	}
9929 
9930 	if (!pmu->check_period)
9931 		pmu->check_period = perf_event_nop_int;
9932 
9933 	if (!pmu->event_idx)
9934 		pmu->event_idx = perf_event_idx_default;
9935 
9936 	list_add_rcu(&pmu->entry, &pmus);
9937 	atomic_set(&pmu->exclusive_cnt, 0);
9938 	ret = 0;
9939 unlock:
9940 	mutex_unlock(&pmus_lock);
9941 
9942 	return ret;
9943 
9944 free_dev:
9945 	device_del(pmu->dev);
9946 	put_device(pmu->dev);
9947 
9948 free_idr:
9949 	if (pmu->type >= PERF_TYPE_MAX)
9950 		idr_remove(&pmu_idr, pmu->type);
9951 
9952 free_pdc:
9953 	free_percpu(pmu->pmu_disable_count);
9954 	goto unlock;
9955 }
9956 EXPORT_SYMBOL_GPL(perf_pmu_register);
9957 
9958 void perf_pmu_unregister(struct pmu *pmu)
9959 {
9960 	mutex_lock(&pmus_lock);
9961 	list_del_rcu(&pmu->entry);
9962 
9963 	/*
9964 	 * We dereference the pmu list under both SRCU and regular RCU, so
9965 	 * synchronize against both of those.
9966 	 */
9967 	synchronize_srcu(&pmus_srcu);
9968 	synchronize_rcu();
9969 
9970 	free_percpu(pmu->pmu_disable_count);
9971 	if (pmu->type >= PERF_TYPE_MAX)
9972 		idr_remove(&pmu_idr, pmu->type);
9973 	if (pmu_bus_running) {
9974 		if (pmu->nr_addr_filters)
9975 			device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9976 		device_del(pmu->dev);
9977 		put_device(pmu->dev);
9978 	}
9979 	free_pmu_context(pmu);
9980 	mutex_unlock(&pmus_lock);
9981 }
9982 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9983 
9984 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9985 {
9986 	struct perf_event_context *ctx = NULL;
9987 	int ret;
9988 
9989 	if (!try_module_get(pmu->module))
9990 		return -ENODEV;
9991 
9992 	/*
9993 	 * A number of pmu->event_init() methods iterate the sibling_list to,
9994 	 * for example, validate if the group fits on the PMU. Therefore,
9995 	 * if this is a sibling event, acquire the ctx->mutex to protect
9996 	 * the sibling_list.
9997 	 */
9998 	if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
9999 		/*
10000 		 * This ctx->mutex can nest when we're called through
10001 		 * inheritance. See the perf_event_ctx_lock_nested() comment.
10002 		 */
10003 		ctx = perf_event_ctx_lock_nested(event->group_leader,
10004 						 SINGLE_DEPTH_NESTING);
10005 		BUG_ON(!ctx);
10006 	}
10007 
10008 	event->pmu = pmu;
10009 	ret = pmu->event_init(event);
10010 
10011 	if (ctx)
10012 		perf_event_ctx_unlock(event->group_leader, ctx);
10013 
10014 	if (!ret) {
10015 		if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
10016 				event_has_any_exclude_flag(event)) {
10017 			if (event->destroy)
10018 				event->destroy(event);
10019 			ret = -EINVAL;
10020 		}
10021 	}
10022 
10023 	if (ret)
10024 		module_put(pmu->module);
10025 
10026 	return ret;
10027 }
10028 
10029 static struct pmu *perf_init_event(struct perf_event *event)
10030 {
10031 	struct pmu *pmu;
10032 	int idx;
10033 	int ret;
10034 
10035 	idx = srcu_read_lock(&pmus_srcu);
10036 
10037 	/* Try parent's PMU first: */
10038 	if (event->parent && event->parent->pmu) {
10039 		pmu = event->parent->pmu;
10040 		ret = perf_try_init_event(pmu, event);
10041 		if (!ret)
10042 			goto unlock;
10043 	}
10044 
10045 	rcu_read_lock();
10046 	pmu = idr_find(&pmu_idr, event->attr.type);
10047 	rcu_read_unlock();
10048 	if (pmu) {
10049 		ret = perf_try_init_event(pmu, event);
10050 		if (ret)
10051 			pmu = ERR_PTR(ret);
10052 		goto unlock;
10053 	}
10054 
10055 	list_for_each_entry_rcu(pmu, &pmus, entry) {
10056 		ret = perf_try_init_event(pmu, event);
10057 		if (!ret)
10058 			goto unlock;
10059 
10060 		if (ret != -ENOENT) {
10061 			pmu = ERR_PTR(ret);
10062 			goto unlock;
10063 		}
10064 	}
10065 	pmu = ERR_PTR(-ENOENT);
10066 unlock:
10067 	srcu_read_unlock(&pmus_srcu, idx);
10068 
10069 	return pmu;
10070 }
10071 
10072 static void attach_sb_event(struct perf_event *event)
10073 {
10074 	struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
10075 
10076 	raw_spin_lock(&pel->lock);
10077 	list_add_rcu(&event->sb_list, &pel->list);
10078 	raw_spin_unlock(&pel->lock);
10079 }
10080 
10081 /*
10082  * We keep a list of all !task (and therefore per-cpu) events
10083  * that need to receive side-band records.
10084  *
10085  * This avoids having to scan all the various PMU per-cpu contexts
10086  * looking for them.
10087  */
10088 static void account_pmu_sb_event(struct perf_event *event)
10089 {
10090 	if (is_sb_event(event))
10091 		attach_sb_event(event);
10092 }
10093 
10094 static void account_event_cpu(struct perf_event *event, int cpu)
10095 {
10096 	if (event->parent)
10097 		return;
10098 
10099 	if (is_cgroup_event(event))
10100 		atomic_inc(&per_cpu(perf_cgroup_events, cpu));
10101 }
10102 
10103 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
10104 static void account_freq_event_nohz(void)
10105 {
10106 #ifdef CONFIG_NO_HZ_FULL
10107 	/* Lock so we don't race with concurrent unaccount */
10108 	spin_lock(&nr_freq_lock);
10109 	if (atomic_inc_return(&nr_freq_events) == 1)
10110 		tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
10111 	spin_unlock(&nr_freq_lock);
10112 #endif
10113 }
10114 
10115 static void account_freq_event(void)
10116 {
10117 	if (tick_nohz_full_enabled())
10118 		account_freq_event_nohz();
10119 	else
10120 		atomic_inc(&nr_freq_events);
10121 }
10122 
10123 
10124 static void account_event(struct perf_event *event)
10125 {
10126 	bool inc = false;
10127 
10128 	if (event->parent)
10129 		return;
10130 
10131 	if (event->attach_state & PERF_ATTACH_TASK)
10132 		inc = true;
10133 	if (event->attr.mmap || event->attr.mmap_data)
10134 		atomic_inc(&nr_mmap_events);
10135 	if (event->attr.comm)
10136 		atomic_inc(&nr_comm_events);
10137 	if (event->attr.namespaces)
10138 		atomic_inc(&nr_namespaces_events);
10139 	if (event->attr.task)
10140 		atomic_inc(&nr_task_events);
10141 	if (event->attr.freq)
10142 		account_freq_event();
10143 	if (event->attr.context_switch) {
10144 		atomic_inc(&nr_switch_events);
10145 		inc = true;
10146 	}
10147 	if (has_branch_stack(event))
10148 		inc = true;
10149 	if (is_cgroup_event(event))
10150 		inc = true;
10151 	if (event->attr.ksymbol)
10152 		atomic_inc(&nr_ksymbol_events);
10153 	if (event->attr.bpf_event)
10154 		atomic_inc(&nr_bpf_events);
10155 
10156 	if (inc) {
10157 		/*
10158 		 * We need the mutex here because static_branch_enable()
10159 		 * must complete *before* the perf_sched_count increment
10160 		 * becomes visible.
10161 		 */
10162 		if (atomic_inc_not_zero(&perf_sched_count))
10163 			goto enabled;
10164 
10165 		mutex_lock(&perf_sched_mutex);
10166 		if (!atomic_read(&perf_sched_count)) {
10167 			static_branch_enable(&perf_sched_events);
10168 			/*
10169 			 * Guarantee that all CPUs observe they key change and
10170 			 * call the perf scheduling hooks before proceeding to
10171 			 * install events that need them.
10172 			 */
10173 			synchronize_rcu();
10174 		}
10175 		/*
10176 		 * Now that we have waited for the sync_sched(), allow further
10177 		 * increments to by-pass the mutex.
10178 		 */
10179 		atomic_inc(&perf_sched_count);
10180 		mutex_unlock(&perf_sched_mutex);
10181 	}
10182 enabled:
10183 
10184 	account_event_cpu(event, event->cpu);
10185 
10186 	account_pmu_sb_event(event);
10187 }
10188 
10189 /*
10190  * Allocate and initialize an event structure
10191  */
10192 static struct perf_event *
10193 perf_event_alloc(struct perf_event_attr *attr, int cpu,
10194 		 struct task_struct *task,
10195 		 struct perf_event *group_leader,
10196 		 struct perf_event *parent_event,
10197 		 perf_overflow_handler_t overflow_handler,
10198 		 void *context, int cgroup_fd)
10199 {
10200 	struct pmu *pmu;
10201 	struct perf_event *event;
10202 	struct hw_perf_event *hwc;
10203 	long err = -EINVAL;
10204 
10205 	if ((unsigned)cpu >= nr_cpu_ids) {
10206 		if (!task || cpu != -1)
10207 			return ERR_PTR(-EINVAL);
10208 	}
10209 
10210 	event = kzalloc(sizeof(*event), GFP_KERNEL);
10211 	if (!event)
10212 		return ERR_PTR(-ENOMEM);
10213 
10214 	/*
10215 	 * Single events are their own group leaders, with an
10216 	 * empty sibling list:
10217 	 */
10218 	if (!group_leader)
10219 		group_leader = event;
10220 
10221 	mutex_init(&event->child_mutex);
10222 	INIT_LIST_HEAD(&event->child_list);
10223 
10224 	INIT_LIST_HEAD(&event->event_entry);
10225 	INIT_LIST_HEAD(&event->sibling_list);
10226 	INIT_LIST_HEAD(&event->active_list);
10227 	init_event_group(event);
10228 	INIT_LIST_HEAD(&event->rb_entry);
10229 	INIT_LIST_HEAD(&event->active_entry);
10230 	INIT_LIST_HEAD(&event->addr_filters.list);
10231 	INIT_HLIST_NODE(&event->hlist_entry);
10232 
10233 
10234 	init_waitqueue_head(&event->waitq);
10235 	init_irq_work(&event->pending, perf_pending_event);
10236 
10237 	mutex_init(&event->mmap_mutex);
10238 	raw_spin_lock_init(&event->addr_filters.lock);
10239 
10240 	atomic_long_set(&event->refcount, 1);
10241 	event->cpu		= cpu;
10242 	event->attr		= *attr;
10243 	event->group_leader	= group_leader;
10244 	event->pmu		= NULL;
10245 	event->oncpu		= -1;
10246 
10247 	event->parent		= parent_event;
10248 
10249 	event->ns		= get_pid_ns(task_active_pid_ns(current));
10250 	event->id		= atomic64_inc_return(&perf_event_id);
10251 
10252 	event->state		= PERF_EVENT_STATE_INACTIVE;
10253 
10254 	if (task) {
10255 		event->attach_state = PERF_ATTACH_TASK;
10256 		/*
10257 		 * XXX pmu::event_init needs to know what task to account to
10258 		 * and we cannot use the ctx information because we need the
10259 		 * pmu before we get a ctx.
10260 		 */
10261 		get_task_struct(task);
10262 		event->hw.target = task;
10263 	}
10264 
10265 	event->clock = &local_clock;
10266 	if (parent_event)
10267 		event->clock = parent_event->clock;
10268 
10269 	if (!overflow_handler && parent_event) {
10270 		overflow_handler = parent_event->overflow_handler;
10271 		context = parent_event->overflow_handler_context;
10272 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
10273 		if (overflow_handler == bpf_overflow_handler) {
10274 			struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
10275 
10276 			if (IS_ERR(prog)) {
10277 				err = PTR_ERR(prog);
10278 				goto err_ns;
10279 			}
10280 			event->prog = prog;
10281 			event->orig_overflow_handler =
10282 				parent_event->orig_overflow_handler;
10283 		}
10284 #endif
10285 	}
10286 
10287 	if (overflow_handler) {
10288 		event->overflow_handler	= overflow_handler;
10289 		event->overflow_handler_context = context;
10290 	} else if (is_write_backward(event)){
10291 		event->overflow_handler = perf_event_output_backward;
10292 		event->overflow_handler_context = NULL;
10293 	} else {
10294 		event->overflow_handler = perf_event_output_forward;
10295 		event->overflow_handler_context = NULL;
10296 	}
10297 
10298 	perf_event__state_init(event);
10299 
10300 	pmu = NULL;
10301 
10302 	hwc = &event->hw;
10303 	hwc->sample_period = attr->sample_period;
10304 	if (attr->freq && attr->sample_freq)
10305 		hwc->sample_period = 1;
10306 	hwc->last_period = hwc->sample_period;
10307 
10308 	local64_set(&hwc->period_left, hwc->sample_period);
10309 
10310 	/*
10311 	 * We currently do not support PERF_SAMPLE_READ on inherited events.
10312 	 * See perf_output_read().
10313 	 */
10314 	if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
10315 		goto err_ns;
10316 
10317 	if (!has_branch_stack(event))
10318 		event->attr.branch_sample_type = 0;
10319 
10320 	if (cgroup_fd != -1) {
10321 		err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
10322 		if (err)
10323 			goto err_ns;
10324 	}
10325 
10326 	pmu = perf_init_event(event);
10327 	if (IS_ERR(pmu)) {
10328 		err = PTR_ERR(pmu);
10329 		goto err_ns;
10330 	}
10331 
10332 	err = exclusive_event_init(event);
10333 	if (err)
10334 		goto err_pmu;
10335 
10336 	if (has_addr_filter(event)) {
10337 		event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
10338 						    sizeof(struct perf_addr_filter_range),
10339 						    GFP_KERNEL);
10340 		if (!event->addr_filter_ranges) {
10341 			err = -ENOMEM;
10342 			goto err_per_task;
10343 		}
10344 
10345 		/*
10346 		 * Clone the parent's vma offsets: they are valid until exec()
10347 		 * even if the mm is not shared with the parent.
10348 		 */
10349 		if (event->parent) {
10350 			struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10351 
10352 			raw_spin_lock_irq(&ifh->lock);
10353 			memcpy(event->addr_filter_ranges,
10354 			       event->parent->addr_filter_ranges,
10355 			       pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
10356 			raw_spin_unlock_irq(&ifh->lock);
10357 		}
10358 
10359 		/* force hw sync on the address filters */
10360 		event->addr_filters_gen = 1;
10361 	}
10362 
10363 	if (!event->parent) {
10364 		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
10365 			err = get_callchain_buffers(attr->sample_max_stack);
10366 			if (err)
10367 				goto err_addr_filters;
10368 		}
10369 	}
10370 
10371 	/* symmetric to unaccount_event() in _free_event() */
10372 	account_event(event);
10373 
10374 	return event;
10375 
10376 err_addr_filters:
10377 	kfree(event->addr_filter_ranges);
10378 
10379 err_per_task:
10380 	exclusive_event_destroy(event);
10381 
10382 err_pmu:
10383 	if (event->destroy)
10384 		event->destroy(event);
10385 	module_put(pmu->module);
10386 err_ns:
10387 	if (is_cgroup_event(event))
10388 		perf_detach_cgroup(event);
10389 	if (event->ns)
10390 		put_pid_ns(event->ns);
10391 	if (event->hw.target)
10392 		put_task_struct(event->hw.target);
10393 	kfree(event);
10394 
10395 	return ERR_PTR(err);
10396 }
10397 
10398 static int perf_copy_attr(struct perf_event_attr __user *uattr,
10399 			  struct perf_event_attr *attr)
10400 {
10401 	u32 size;
10402 	int ret;
10403 
10404 	if (!access_ok(uattr, PERF_ATTR_SIZE_VER0))
10405 		return -EFAULT;
10406 
10407 	/*
10408 	 * zero the full structure, so that a short copy will be nice.
10409 	 */
10410 	memset(attr, 0, sizeof(*attr));
10411 
10412 	ret = get_user(size, &uattr->size);
10413 	if (ret)
10414 		return ret;
10415 
10416 	if (size > PAGE_SIZE)	/* silly large */
10417 		goto err_size;
10418 
10419 	if (!size)		/* abi compat */
10420 		size = PERF_ATTR_SIZE_VER0;
10421 
10422 	if (size < PERF_ATTR_SIZE_VER0)
10423 		goto err_size;
10424 
10425 	/*
10426 	 * If we're handed a bigger struct than we know of,
10427 	 * ensure all the unknown bits are 0 - i.e. new
10428 	 * user-space does not rely on any kernel feature
10429 	 * extensions we dont know about yet.
10430 	 */
10431 	if (size > sizeof(*attr)) {
10432 		unsigned char __user *addr;
10433 		unsigned char __user *end;
10434 		unsigned char val;
10435 
10436 		addr = (void __user *)uattr + sizeof(*attr);
10437 		end  = (void __user *)uattr + size;
10438 
10439 		for (; addr < end; addr++) {
10440 			ret = get_user(val, addr);
10441 			if (ret)
10442 				return ret;
10443 			if (val)
10444 				goto err_size;
10445 		}
10446 		size = sizeof(*attr);
10447 	}
10448 
10449 	ret = copy_from_user(attr, uattr, size);
10450 	if (ret)
10451 		return -EFAULT;
10452 
10453 	attr->size = size;
10454 
10455 	if (attr->__reserved_1)
10456 		return -EINVAL;
10457 
10458 	if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
10459 		return -EINVAL;
10460 
10461 	if (attr->read_format & ~(PERF_FORMAT_MAX-1))
10462 		return -EINVAL;
10463 
10464 	if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
10465 		u64 mask = attr->branch_sample_type;
10466 
10467 		/* only using defined bits */
10468 		if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
10469 			return -EINVAL;
10470 
10471 		/* at least one branch bit must be set */
10472 		if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
10473 			return -EINVAL;
10474 
10475 		/* propagate priv level, when not set for branch */
10476 		if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
10477 
10478 			/* exclude_kernel checked on syscall entry */
10479 			if (!attr->exclude_kernel)
10480 				mask |= PERF_SAMPLE_BRANCH_KERNEL;
10481 
10482 			if (!attr->exclude_user)
10483 				mask |= PERF_SAMPLE_BRANCH_USER;
10484 
10485 			if (!attr->exclude_hv)
10486 				mask |= PERF_SAMPLE_BRANCH_HV;
10487 			/*
10488 			 * adjust user setting (for HW filter setup)
10489 			 */
10490 			attr->branch_sample_type = mask;
10491 		}
10492 		/* privileged levels capture (kernel, hv): check permissions */
10493 		if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
10494 		    && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10495 			return -EACCES;
10496 	}
10497 
10498 	if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
10499 		ret = perf_reg_validate(attr->sample_regs_user);
10500 		if (ret)
10501 			return ret;
10502 	}
10503 
10504 	if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
10505 		if (!arch_perf_have_user_stack_dump())
10506 			return -ENOSYS;
10507 
10508 		/*
10509 		 * We have __u32 type for the size, but so far
10510 		 * we can only use __u16 as maximum due to the
10511 		 * __u16 sample size limit.
10512 		 */
10513 		if (attr->sample_stack_user >= USHRT_MAX)
10514 			return -EINVAL;
10515 		else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
10516 			return -EINVAL;
10517 	}
10518 
10519 	if (!attr->sample_max_stack)
10520 		attr->sample_max_stack = sysctl_perf_event_max_stack;
10521 
10522 	if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
10523 		ret = perf_reg_validate(attr->sample_regs_intr);
10524 out:
10525 	return ret;
10526 
10527 err_size:
10528 	put_user(sizeof(*attr), &uattr->size);
10529 	ret = -E2BIG;
10530 	goto out;
10531 }
10532 
10533 static int
10534 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
10535 {
10536 	struct ring_buffer *rb = NULL;
10537 	int ret = -EINVAL;
10538 
10539 	if (!output_event)
10540 		goto set;
10541 
10542 	/* don't allow circular references */
10543 	if (event == output_event)
10544 		goto out;
10545 
10546 	/*
10547 	 * Don't allow cross-cpu buffers
10548 	 */
10549 	if (output_event->cpu != event->cpu)
10550 		goto out;
10551 
10552 	/*
10553 	 * If its not a per-cpu rb, it must be the same task.
10554 	 */
10555 	if (output_event->cpu == -1 && output_event->ctx != event->ctx)
10556 		goto out;
10557 
10558 	/*
10559 	 * Mixing clocks in the same buffer is trouble you don't need.
10560 	 */
10561 	if (output_event->clock != event->clock)
10562 		goto out;
10563 
10564 	/*
10565 	 * Either writing ring buffer from beginning or from end.
10566 	 * Mixing is not allowed.
10567 	 */
10568 	if (is_write_backward(output_event) != is_write_backward(event))
10569 		goto out;
10570 
10571 	/*
10572 	 * If both events generate aux data, they must be on the same PMU
10573 	 */
10574 	if (has_aux(event) && has_aux(output_event) &&
10575 	    event->pmu != output_event->pmu)
10576 		goto out;
10577 
10578 set:
10579 	mutex_lock(&event->mmap_mutex);
10580 	/* Can't redirect output if we've got an active mmap() */
10581 	if (atomic_read(&event->mmap_count))
10582 		goto unlock;
10583 
10584 	if (output_event) {
10585 		/* get the rb we want to redirect to */
10586 		rb = ring_buffer_get(output_event);
10587 		if (!rb)
10588 			goto unlock;
10589 	}
10590 
10591 	ring_buffer_attach(event, rb);
10592 
10593 	ret = 0;
10594 unlock:
10595 	mutex_unlock(&event->mmap_mutex);
10596 
10597 out:
10598 	return ret;
10599 }
10600 
10601 static void mutex_lock_double(struct mutex *a, struct mutex *b)
10602 {
10603 	if (b < a)
10604 		swap(a, b);
10605 
10606 	mutex_lock(a);
10607 	mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
10608 }
10609 
10610 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
10611 {
10612 	bool nmi_safe = false;
10613 
10614 	switch (clk_id) {
10615 	case CLOCK_MONOTONIC:
10616 		event->clock = &ktime_get_mono_fast_ns;
10617 		nmi_safe = true;
10618 		break;
10619 
10620 	case CLOCK_MONOTONIC_RAW:
10621 		event->clock = &ktime_get_raw_fast_ns;
10622 		nmi_safe = true;
10623 		break;
10624 
10625 	case CLOCK_REALTIME:
10626 		event->clock = &ktime_get_real_ns;
10627 		break;
10628 
10629 	case CLOCK_BOOTTIME:
10630 		event->clock = &ktime_get_boot_ns;
10631 		break;
10632 
10633 	case CLOCK_TAI:
10634 		event->clock = &ktime_get_tai_ns;
10635 		break;
10636 
10637 	default:
10638 		return -EINVAL;
10639 	}
10640 
10641 	if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
10642 		return -EINVAL;
10643 
10644 	return 0;
10645 }
10646 
10647 /*
10648  * Variation on perf_event_ctx_lock_nested(), except we take two context
10649  * mutexes.
10650  */
10651 static struct perf_event_context *
10652 __perf_event_ctx_lock_double(struct perf_event *group_leader,
10653 			     struct perf_event_context *ctx)
10654 {
10655 	struct perf_event_context *gctx;
10656 
10657 again:
10658 	rcu_read_lock();
10659 	gctx = READ_ONCE(group_leader->ctx);
10660 	if (!refcount_inc_not_zero(&gctx->refcount)) {
10661 		rcu_read_unlock();
10662 		goto again;
10663 	}
10664 	rcu_read_unlock();
10665 
10666 	mutex_lock_double(&gctx->mutex, &ctx->mutex);
10667 
10668 	if (group_leader->ctx != gctx) {
10669 		mutex_unlock(&ctx->mutex);
10670 		mutex_unlock(&gctx->mutex);
10671 		put_ctx(gctx);
10672 		goto again;
10673 	}
10674 
10675 	return gctx;
10676 }
10677 
10678 /**
10679  * sys_perf_event_open - open a performance event, associate it to a task/cpu
10680  *
10681  * @attr_uptr:	event_id type attributes for monitoring/sampling
10682  * @pid:		target pid
10683  * @cpu:		target cpu
10684  * @group_fd:		group leader event fd
10685  */
10686 SYSCALL_DEFINE5(perf_event_open,
10687 		struct perf_event_attr __user *, attr_uptr,
10688 		pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
10689 {
10690 	struct perf_event *group_leader = NULL, *output_event = NULL;
10691 	struct perf_event *event, *sibling;
10692 	struct perf_event_attr attr;
10693 	struct perf_event_context *ctx, *uninitialized_var(gctx);
10694 	struct file *event_file = NULL;
10695 	struct fd group = {NULL, 0};
10696 	struct task_struct *task = NULL;
10697 	struct pmu *pmu;
10698 	int event_fd;
10699 	int move_group = 0;
10700 	int err;
10701 	int f_flags = O_RDWR;
10702 	int cgroup_fd = -1;
10703 
10704 	/* for future expandability... */
10705 	if (flags & ~PERF_FLAG_ALL)
10706 		return -EINVAL;
10707 
10708 	err = perf_copy_attr(attr_uptr, &attr);
10709 	if (err)
10710 		return err;
10711 
10712 	if (!attr.exclude_kernel) {
10713 		if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10714 			return -EACCES;
10715 	}
10716 
10717 	if (attr.namespaces) {
10718 		if (!capable(CAP_SYS_ADMIN))
10719 			return -EACCES;
10720 	}
10721 
10722 	if (attr.freq) {
10723 		if (attr.sample_freq > sysctl_perf_event_sample_rate)
10724 			return -EINVAL;
10725 	} else {
10726 		if (attr.sample_period & (1ULL << 63))
10727 			return -EINVAL;
10728 	}
10729 
10730 	/* Only privileged users can get physical addresses */
10731 	if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
10732 	    perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10733 		return -EACCES;
10734 
10735 	/*
10736 	 * In cgroup mode, the pid argument is used to pass the fd
10737 	 * opened to the cgroup directory in cgroupfs. The cpu argument
10738 	 * designates the cpu on which to monitor threads from that
10739 	 * cgroup.
10740 	 */
10741 	if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
10742 		return -EINVAL;
10743 
10744 	if (flags & PERF_FLAG_FD_CLOEXEC)
10745 		f_flags |= O_CLOEXEC;
10746 
10747 	event_fd = get_unused_fd_flags(f_flags);
10748 	if (event_fd < 0)
10749 		return event_fd;
10750 
10751 	if (group_fd != -1) {
10752 		err = perf_fget_light(group_fd, &group);
10753 		if (err)
10754 			goto err_fd;
10755 		group_leader = group.file->private_data;
10756 		if (flags & PERF_FLAG_FD_OUTPUT)
10757 			output_event = group_leader;
10758 		if (flags & PERF_FLAG_FD_NO_GROUP)
10759 			group_leader = NULL;
10760 	}
10761 
10762 	if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
10763 		task = find_lively_task_by_vpid(pid);
10764 		if (IS_ERR(task)) {
10765 			err = PTR_ERR(task);
10766 			goto err_group_fd;
10767 		}
10768 	}
10769 
10770 	if (task && group_leader &&
10771 	    group_leader->attr.inherit != attr.inherit) {
10772 		err = -EINVAL;
10773 		goto err_task;
10774 	}
10775 
10776 	if (task) {
10777 		err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
10778 		if (err)
10779 			goto err_task;
10780 
10781 		/*
10782 		 * Reuse ptrace permission checks for now.
10783 		 *
10784 		 * We must hold cred_guard_mutex across this and any potential
10785 		 * perf_install_in_context() call for this new event to
10786 		 * serialize against exec() altering our credentials (and the
10787 		 * perf_event_exit_task() that could imply).
10788 		 */
10789 		err = -EACCES;
10790 		if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
10791 			goto err_cred;
10792 	}
10793 
10794 	if (flags & PERF_FLAG_PID_CGROUP)
10795 		cgroup_fd = pid;
10796 
10797 	event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
10798 				 NULL, NULL, cgroup_fd);
10799 	if (IS_ERR(event)) {
10800 		err = PTR_ERR(event);
10801 		goto err_cred;
10802 	}
10803 
10804 	if (is_sampling_event(event)) {
10805 		if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
10806 			err = -EOPNOTSUPP;
10807 			goto err_alloc;
10808 		}
10809 	}
10810 
10811 	/*
10812 	 * Special case software events and allow them to be part of
10813 	 * any hardware group.
10814 	 */
10815 	pmu = event->pmu;
10816 
10817 	if (attr.use_clockid) {
10818 		err = perf_event_set_clock(event, attr.clockid);
10819 		if (err)
10820 			goto err_alloc;
10821 	}
10822 
10823 	if (pmu->task_ctx_nr == perf_sw_context)
10824 		event->event_caps |= PERF_EV_CAP_SOFTWARE;
10825 
10826 	if (group_leader) {
10827 		if (is_software_event(event) &&
10828 		    !in_software_context(group_leader)) {
10829 			/*
10830 			 * If the event is a sw event, but the group_leader
10831 			 * is on hw context.
10832 			 *
10833 			 * Allow the addition of software events to hw
10834 			 * groups, this is safe because software events
10835 			 * never fail to schedule.
10836 			 */
10837 			pmu = group_leader->ctx->pmu;
10838 		} else if (!is_software_event(event) &&
10839 			   is_software_event(group_leader) &&
10840 			   (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10841 			/*
10842 			 * In case the group is a pure software group, and we
10843 			 * try to add a hardware event, move the whole group to
10844 			 * the hardware context.
10845 			 */
10846 			move_group = 1;
10847 		}
10848 	}
10849 
10850 	/*
10851 	 * Get the target context (task or percpu):
10852 	 */
10853 	ctx = find_get_context(pmu, task, event);
10854 	if (IS_ERR(ctx)) {
10855 		err = PTR_ERR(ctx);
10856 		goto err_alloc;
10857 	}
10858 
10859 	if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
10860 		err = -EBUSY;
10861 		goto err_context;
10862 	}
10863 
10864 	/*
10865 	 * Look up the group leader (we will attach this event to it):
10866 	 */
10867 	if (group_leader) {
10868 		err = -EINVAL;
10869 
10870 		/*
10871 		 * Do not allow a recursive hierarchy (this new sibling
10872 		 * becoming part of another group-sibling):
10873 		 */
10874 		if (group_leader->group_leader != group_leader)
10875 			goto err_context;
10876 
10877 		/* All events in a group should have the same clock */
10878 		if (group_leader->clock != event->clock)
10879 			goto err_context;
10880 
10881 		/*
10882 		 * Make sure we're both events for the same CPU;
10883 		 * grouping events for different CPUs is broken; since
10884 		 * you can never concurrently schedule them anyhow.
10885 		 */
10886 		if (group_leader->cpu != event->cpu)
10887 			goto err_context;
10888 
10889 		/*
10890 		 * Make sure we're both on the same task, or both
10891 		 * per-CPU events.
10892 		 */
10893 		if (group_leader->ctx->task != ctx->task)
10894 			goto err_context;
10895 
10896 		/*
10897 		 * Do not allow to attach to a group in a different task
10898 		 * or CPU context. If we're moving SW events, we'll fix
10899 		 * this up later, so allow that.
10900 		 */
10901 		if (!move_group && group_leader->ctx != ctx)
10902 			goto err_context;
10903 
10904 		/*
10905 		 * Only a group leader can be exclusive or pinned
10906 		 */
10907 		if (attr.exclusive || attr.pinned)
10908 			goto err_context;
10909 	}
10910 
10911 	if (output_event) {
10912 		err = perf_event_set_output(event, output_event);
10913 		if (err)
10914 			goto err_context;
10915 	}
10916 
10917 	event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10918 					f_flags);
10919 	if (IS_ERR(event_file)) {
10920 		err = PTR_ERR(event_file);
10921 		event_file = NULL;
10922 		goto err_context;
10923 	}
10924 
10925 	if (move_group) {
10926 		gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10927 
10928 		if (gctx->task == TASK_TOMBSTONE) {
10929 			err = -ESRCH;
10930 			goto err_locked;
10931 		}
10932 
10933 		/*
10934 		 * Check if we raced against another sys_perf_event_open() call
10935 		 * moving the software group underneath us.
10936 		 */
10937 		if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10938 			/*
10939 			 * If someone moved the group out from under us, check
10940 			 * if this new event wound up on the same ctx, if so
10941 			 * its the regular !move_group case, otherwise fail.
10942 			 */
10943 			if (gctx != ctx) {
10944 				err = -EINVAL;
10945 				goto err_locked;
10946 			} else {
10947 				perf_event_ctx_unlock(group_leader, gctx);
10948 				move_group = 0;
10949 			}
10950 		}
10951 	} else {
10952 		mutex_lock(&ctx->mutex);
10953 	}
10954 
10955 	if (ctx->task == TASK_TOMBSTONE) {
10956 		err = -ESRCH;
10957 		goto err_locked;
10958 	}
10959 
10960 	if (!perf_event_validate_size(event)) {
10961 		err = -E2BIG;
10962 		goto err_locked;
10963 	}
10964 
10965 	if (!task) {
10966 		/*
10967 		 * Check if the @cpu we're creating an event for is online.
10968 		 *
10969 		 * We use the perf_cpu_context::ctx::mutex to serialize against
10970 		 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10971 		 */
10972 		struct perf_cpu_context *cpuctx =
10973 			container_of(ctx, struct perf_cpu_context, ctx);
10974 
10975 		if (!cpuctx->online) {
10976 			err = -ENODEV;
10977 			goto err_locked;
10978 		}
10979 	}
10980 
10981 
10982 	/*
10983 	 * Must be under the same ctx::mutex as perf_install_in_context(),
10984 	 * because we need to serialize with concurrent event creation.
10985 	 */
10986 	if (!exclusive_event_installable(event, ctx)) {
10987 		/* exclusive and group stuff are assumed mutually exclusive */
10988 		WARN_ON_ONCE(move_group);
10989 
10990 		err = -EBUSY;
10991 		goto err_locked;
10992 	}
10993 
10994 	WARN_ON_ONCE(ctx->parent_ctx);
10995 
10996 	/*
10997 	 * This is the point on no return; we cannot fail hereafter. This is
10998 	 * where we start modifying current state.
10999 	 */
11000 
11001 	if (move_group) {
11002 		/*
11003 		 * See perf_event_ctx_lock() for comments on the details
11004 		 * of swizzling perf_event::ctx.
11005 		 */
11006 		perf_remove_from_context(group_leader, 0);
11007 		put_ctx(gctx);
11008 
11009 		for_each_sibling_event(sibling, group_leader) {
11010 			perf_remove_from_context(sibling, 0);
11011 			put_ctx(gctx);
11012 		}
11013 
11014 		/*
11015 		 * Wait for everybody to stop referencing the events through
11016 		 * the old lists, before installing it on new lists.
11017 		 */
11018 		synchronize_rcu();
11019 
11020 		/*
11021 		 * Install the group siblings before the group leader.
11022 		 *
11023 		 * Because a group leader will try and install the entire group
11024 		 * (through the sibling list, which is still in-tact), we can
11025 		 * end up with siblings installed in the wrong context.
11026 		 *
11027 		 * By installing siblings first we NO-OP because they're not
11028 		 * reachable through the group lists.
11029 		 */
11030 		for_each_sibling_event(sibling, group_leader) {
11031 			perf_event__state_init(sibling);
11032 			perf_install_in_context(ctx, sibling, sibling->cpu);
11033 			get_ctx(ctx);
11034 		}
11035 
11036 		/*
11037 		 * Removing from the context ends up with disabled
11038 		 * event. What we want here is event in the initial
11039 		 * startup state, ready to be add into new context.
11040 		 */
11041 		perf_event__state_init(group_leader);
11042 		perf_install_in_context(ctx, group_leader, group_leader->cpu);
11043 		get_ctx(ctx);
11044 	}
11045 
11046 	/*
11047 	 * Precalculate sample_data sizes; do while holding ctx::mutex such
11048 	 * that we're serialized against further additions and before
11049 	 * perf_install_in_context() which is the point the event is active and
11050 	 * can use these values.
11051 	 */
11052 	perf_event__header_size(event);
11053 	perf_event__id_header_size(event);
11054 
11055 	event->owner = current;
11056 
11057 	perf_install_in_context(ctx, event, event->cpu);
11058 	perf_unpin_context(ctx);
11059 
11060 	if (move_group)
11061 		perf_event_ctx_unlock(group_leader, gctx);
11062 	mutex_unlock(&ctx->mutex);
11063 
11064 	if (task) {
11065 		mutex_unlock(&task->signal->cred_guard_mutex);
11066 		put_task_struct(task);
11067 	}
11068 
11069 	mutex_lock(&current->perf_event_mutex);
11070 	list_add_tail(&event->owner_entry, &current->perf_event_list);
11071 	mutex_unlock(&current->perf_event_mutex);
11072 
11073 	/*
11074 	 * Drop the reference on the group_event after placing the
11075 	 * new event on the sibling_list. This ensures destruction
11076 	 * of the group leader will find the pointer to itself in
11077 	 * perf_group_detach().
11078 	 */
11079 	fdput(group);
11080 	fd_install(event_fd, event_file);
11081 	return event_fd;
11082 
11083 err_locked:
11084 	if (move_group)
11085 		perf_event_ctx_unlock(group_leader, gctx);
11086 	mutex_unlock(&ctx->mutex);
11087 /* err_file: */
11088 	fput(event_file);
11089 err_context:
11090 	perf_unpin_context(ctx);
11091 	put_ctx(ctx);
11092 err_alloc:
11093 	/*
11094 	 * If event_file is set, the fput() above will have called ->release()
11095 	 * and that will take care of freeing the event.
11096 	 */
11097 	if (!event_file)
11098 		free_event(event);
11099 err_cred:
11100 	if (task)
11101 		mutex_unlock(&task->signal->cred_guard_mutex);
11102 err_task:
11103 	if (task)
11104 		put_task_struct(task);
11105 err_group_fd:
11106 	fdput(group);
11107 err_fd:
11108 	put_unused_fd(event_fd);
11109 	return err;
11110 }
11111 
11112 /**
11113  * perf_event_create_kernel_counter
11114  *
11115  * @attr: attributes of the counter to create
11116  * @cpu: cpu in which the counter is bound
11117  * @task: task to profile (NULL for percpu)
11118  */
11119 struct perf_event *
11120 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
11121 				 struct task_struct *task,
11122 				 perf_overflow_handler_t overflow_handler,
11123 				 void *context)
11124 {
11125 	struct perf_event_context *ctx;
11126 	struct perf_event *event;
11127 	int err;
11128 
11129 	/*
11130 	 * Get the target context (task or percpu):
11131 	 */
11132 
11133 	event = perf_event_alloc(attr, cpu, task, NULL, NULL,
11134 				 overflow_handler, context, -1);
11135 	if (IS_ERR(event)) {
11136 		err = PTR_ERR(event);
11137 		goto err;
11138 	}
11139 
11140 	/* Mark owner so we could distinguish it from user events. */
11141 	event->owner = TASK_TOMBSTONE;
11142 
11143 	ctx = find_get_context(event->pmu, task, event);
11144 	if (IS_ERR(ctx)) {
11145 		err = PTR_ERR(ctx);
11146 		goto err_free;
11147 	}
11148 
11149 	WARN_ON_ONCE(ctx->parent_ctx);
11150 	mutex_lock(&ctx->mutex);
11151 	if (ctx->task == TASK_TOMBSTONE) {
11152 		err = -ESRCH;
11153 		goto err_unlock;
11154 	}
11155 
11156 	if (!task) {
11157 		/*
11158 		 * Check if the @cpu we're creating an event for is online.
11159 		 *
11160 		 * We use the perf_cpu_context::ctx::mutex to serialize against
11161 		 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11162 		 */
11163 		struct perf_cpu_context *cpuctx =
11164 			container_of(ctx, struct perf_cpu_context, ctx);
11165 		if (!cpuctx->online) {
11166 			err = -ENODEV;
11167 			goto err_unlock;
11168 		}
11169 	}
11170 
11171 	if (!exclusive_event_installable(event, ctx)) {
11172 		err = -EBUSY;
11173 		goto err_unlock;
11174 	}
11175 
11176 	perf_install_in_context(ctx, event, cpu);
11177 	perf_unpin_context(ctx);
11178 	mutex_unlock(&ctx->mutex);
11179 
11180 	return event;
11181 
11182 err_unlock:
11183 	mutex_unlock(&ctx->mutex);
11184 	perf_unpin_context(ctx);
11185 	put_ctx(ctx);
11186 err_free:
11187 	free_event(event);
11188 err:
11189 	return ERR_PTR(err);
11190 }
11191 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
11192 
11193 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
11194 {
11195 	struct perf_event_context *src_ctx;
11196 	struct perf_event_context *dst_ctx;
11197 	struct perf_event *event, *tmp;
11198 	LIST_HEAD(events);
11199 
11200 	src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
11201 	dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
11202 
11203 	/*
11204 	 * See perf_event_ctx_lock() for comments on the details
11205 	 * of swizzling perf_event::ctx.
11206 	 */
11207 	mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
11208 	list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
11209 				 event_entry) {
11210 		perf_remove_from_context(event, 0);
11211 		unaccount_event_cpu(event, src_cpu);
11212 		put_ctx(src_ctx);
11213 		list_add(&event->migrate_entry, &events);
11214 	}
11215 
11216 	/*
11217 	 * Wait for the events to quiesce before re-instating them.
11218 	 */
11219 	synchronize_rcu();
11220 
11221 	/*
11222 	 * Re-instate events in 2 passes.
11223 	 *
11224 	 * Skip over group leaders and only install siblings on this first
11225 	 * pass, siblings will not get enabled without a leader, however a
11226 	 * leader will enable its siblings, even if those are still on the old
11227 	 * context.
11228 	 */
11229 	list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11230 		if (event->group_leader == event)
11231 			continue;
11232 
11233 		list_del(&event->migrate_entry);
11234 		if (event->state >= PERF_EVENT_STATE_OFF)
11235 			event->state = PERF_EVENT_STATE_INACTIVE;
11236 		account_event_cpu(event, dst_cpu);
11237 		perf_install_in_context(dst_ctx, event, dst_cpu);
11238 		get_ctx(dst_ctx);
11239 	}
11240 
11241 	/*
11242 	 * Once all the siblings are setup properly, install the group leaders
11243 	 * to make it go.
11244 	 */
11245 	list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11246 		list_del(&event->migrate_entry);
11247 		if (event->state >= PERF_EVENT_STATE_OFF)
11248 			event->state = PERF_EVENT_STATE_INACTIVE;
11249 		account_event_cpu(event, dst_cpu);
11250 		perf_install_in_context(dst_ctx, event, dst_cpu);
11251 		get_ctx(dst_ctx);
11252 	}
11253 	mutex_unlock(&dst_ctx->mutex);
11254 	mutex_unlock(&src_ctx->mutex);
11255 }
11256 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
11257 
11258 static void sync_child_event(struct perf_event *child_event,
11259 			       struct task_struct *child)
11260 {
11261 	struct perf_event *parent_event = child_event->parent;
11262 	u64 child_val;
11263 
11264 	if (child_event->attr.inherit_stat)
11265 		perf_event_read_event(child_event, child);
11266 
11267 	child_val = perf_event_count(child_event);
11268 
11269 	/*
11270 	 * Add back the child's count to the parent's count:
11271 	 */
11272 	atomic64_add(child_val, &parent_event->child_count);
11273 	atomic64_add(child_event->total_time_enabled,
11274 		     &parent_event->child_total_time_enabled);
11275 	atomic64_add(child_event->total_time_running,
11276 		     &parent_event->child_total_time_running);
11277 }
11278 
11279 static void
11280 perf_event_exit_event(struct perf_event *child_event,
11281 		      struct perf_event_context *child_ctx,
11282 		      struct task_struct *child)
11283 {
11284 	struct perf_event *parent_event = child_event->parent;
11285 
11286 	/*
11287 	 * Do not destroy the 'original' grouping; because of the context
11288 	 * switch optimization the original events could've ended up in a
11289 	 * random child task.
11290 	 *
11291 	 * If we were to destroy the original group, all group related
11292 	 * operations would cease to function properly after this random
11293 	 * child dies.
11294 	 *
11295 	 * Do destroy all inherited groups, we don't care about those
11296 	 * and being thorough is better.
11297 	 */
11298 	raw_spin_lock_irq(&child_ctx->lock);
11299 	WARN_ON_ONCE(child_ctx->is_active);
11300 
11301 	if (parent_event)
11302 		perf_group_detach(child_event);
11303 	list_del_event(child_event, child_ctx);
11304 	perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
11305 	raw_spin_unlock_irq(&child_ctx->lock);
11306 
11307 	/*
11308 	 * Parent events are governed by their filedesc, retain them.
11309 	 */
11310 	if (!parent_event) {
11311 		perf_event_wakeup(child_event);
11312 		return;
11313 	}
11314 	/*
11315 	 * Child events can be cleaned up.
11316 	 */
11317 
11318 	sync_child_event(child_event, child);
11319 
11320 	/*
11321 	 * Remove this event from the parent's list
11322 	 */
11323 	WARN_ON_ONCE(parent_event->ctx->parent_ctx);
11324 	mutex_lock(&parent_event->child_mutex);
11325 	list_del_init(&child_event->child_list);
11326 	mutex_unlock(&parent_event->child_mutex);
11327 
11328 	/*
11329 	 * Kick perf_poll() for is_event_hup().
11330 	 */
11331 	perf_event_wakeup(parent_event);
11332 	free_event(child_event);
11333 	put_event(parent_event);
11334 }
11335 
11336 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
11337 {
11338 	struct perf_event_context *child_ctx, *clone_ctx = NULL;
11339 	struct perf_event *child_event, *next;
11340 
11341 	WARN_ON_ONCE(child != current);
11342 
11343 	child_ctx = perf_pin_task_context(child, ctxn);
11344 	if (!child_ctx)
11345 		return;
11346 
11347 	/*
11348 	 * In order to reduce the amount of tricky in ctx tear-down, we hold
11349 	 * ctx::mutex over the entire thing. This serializes against almost
11350 	 * everything that wants to access the ctx.
11351 	 *
11352 	 * The exception is sys_perf_event_open() /
11353 	 * perf_event_create_kernel_count() which does find_get_context()
11354 	 * without ctx::mutex (it cannot because of the move_group double mutex
11355 	 * lock thing). See the comments in perf_install_in_context().
11356 	 */
11357 	mutex_lock(&child_ctx->mutex);
11358 
11359 	/*
11360 	 * In a single ctx::lock section, de-schedule the events and detach the
11361 	 * context from the task such that we cannot ever get it scheduled back
11362 	 * in.
11363 	 */
11364 	raw_spin_lock_irq(&child_ctx->lock);
11365 	task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
11366 
11367 	/*
11368 	 * Now that the context is inactive, destroy the task <-> ctx relation
11369 	 * and mark the context dead.
11370 	 */
11371 	RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
11372 	put_ctx(child_ctx); /* cannot be last */
11373 	WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
11374 	put_task_struct(current); /* cannot be last */
11375 
11376 	clone_ctx = unclone_ctx(child_ctx);
11377 	raw_spin_unlock_irq(&child_ctx->lock);
11378 
11379 	if (clone_ctx)
11380 		put_ctx(clone_ctx);
11381 
11382 	/*
11383 	 * Report the task dead after unscheduling the events so that we
11384 	 * won't get any samples after PERF_RECORD_EXIT. We can however still
11385 	 * get a few PERF_RECORD_READ events.
11386 	 */
11387 	perf_event_task(child, child_ctx, 0);
11388 
11389 	list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
11390 		perf_event_exit_event(child_event, child_ctx, child);
11391 
11392 	mutex_unlock(&child_ctx->mutex);
11393 
11394 	put_ctx(child_ctx);
11395 }
11396 
11397 /*
11398  * When a child task exits, feed back event values to parent events.
11399  *
11400  * Can be called with cred_guard_mutex held when called from
11401  * install_exec_creds().
11402  */
11403 void perf_event_exit_task(struct task_struct *child)
11404 {
11405 	struct perf_event *event, *tmp;
11406 	int ctxn;
11407 
11408 	mutex_lock(&child->perf_event_mutex);
11409 	list_for_each_entry_safe(event, tmp, &child->perf_event_list,
11410 				 owner_entry) {
11411 		list_del_init(&event->owner_entry);
11412 
11413 		/*
11414 		 * Ensure the list deletion is visible before we clear
11415 		 * the owner, closes a race against perf_release() where
11416 		 * we need to serialize on the owner->perf_event_mutex.
11417 		 */
11418 		smp_store_release(&event->owner, NULL);
11419 	}
11420 	mutex_unlock(&child->perf_event_mutex);
11421 
11422 	for_each_task_context_nr(ctxn)
11423 		perf_event_exit_task_context(child, ctxn);
11424 
11425 	/*
11426 	 * The perf_event_exit_task_context calls perf_event_task
11427 	 * with child's task_ctx, which generates EXIT events for
11428 	 * child contexts and sets child->perf_event_ctxp[] to NULL.
11429 	 * At this point we need to send EXIT events to cpu contexts.
11430 	 */
11431 	perf_event_task(child, NULL, 0);
11432 }
11433 
11434 static void perf_free_event(struct perf_event *event,
11435 			    struct perf_event_context *ctx)
11436 {
11437 	struct perf_event *parent = event->parent;
11438 
11439 	if (WARN_ON_ONCE(!parent))
11440 		return;
11441 
11442 	mutex_lock(&parent->child_mutex);
11443 	list_del_init(&event->child_list);
11444 	mutex_unlock(&parent->child_mutex);
11445 
11446 	put_event(parent);
11447 
11448 	raw_spin_lock_irq(&ctx->lock);
11449 	perf_group_detach(event);
11450 	list_del_event(event, ctx);
11451 	raw_spin_unlock_irq(&ctx->lock);
11452 	free_event(event);
11453 }
11454 
11455 /*
11456  * Free an unexposed, unused context as created by inheritance by
11457  * perf_event_init_task below, used by fork() in case of fail.
11458  *
11459  * Not all locks are strictly required, but take them anyway to be nice and
11460  * help out with the lockdep assertions.
11461  */
11462 void perf_event_free_task(struct task_struct *task)
11463 {
11464 	struct perf_event_context *ctx;
11465 	struct perf_event *event, *tmp;
11466 	int ctxn;
11467 
11468 	for_each_task_context_nr(ctxn) {
11469 		ctx = task->perf_event_ctxp[ctxn];
11470 		if (!ctx)
11471 			continue;
11472 
11473 		mutex_lock(&ctx->mutex);
11474 		raw_spin_lock_irq(&ctx->lock);
11475 		/*
11476 		 * Destroy the task <-> ctx relation and mark the context dead.
11477 		 *
11478 		 * This is important because even though the task hasn't been
11479 		 * exposed yet the context has been (through child_list).
11480 		 */
11481 		RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
11482 		WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
11483 		put_task_struct(task); /* cannot be last */
11484 		raw_spin_unlock_irq(&ctx->lock);
11485 
11486 		list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
11487 			perf_free_event(event, ctx);
11488 
11489 		mutex_unlock(&ctx->mutex);
11490 		put_ctx(ctx);
11491 	}
11492 }
11493 
11494 void perf_event_delayed_put(struct task_struct *task)
11495 {
11496 	int ctxn;
11497 
11498 	for_each_task_context_nr(ctxn)
11499 		WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
11500 }
11501 
11502 struct file *perf_event_get(unsigned int fd)
11503 {
11504 	struct file *file;
11505 
11506 	file = fget_raw(fd);
11507 	if (!file)
11508 		return ERR_PTR(-EBADF);
11509 
11510 	if (file->f_op != &perf_fops) {
11511 		fput(file);
11512 		return ERR_PTR(-EBADF);
11513 	}
11514 
11515 	return file;
11516 }
11517 
11518 const struct perf_event *perf_get_event(struct file *file)
11519 {
11520 	if (file->f_op != &perf_fops)
11521 		return ERR_PTR(-EINVAL);
11522 
11523 	return file->private_data;
11524 }
11525 
11526 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
11527 {
11528 	if (!event)
11529 		return ERR_PTR(-EINVAL);
11530 
11531 	return &event->attr;
11532 }
11533 
11534 /*
11535  * Inherit an event from parent task to child task.
11536  *
11537  * Returns:
11538  *  - valid pointer on success
11539  *  - NULL for orphaned events
11540  *  - IS_ERR() on error
11541  */
11542 static struct perf_event *
11543 inherit_event(struct perf_event *parent_event,
11544 	      struct task_struct *parent,
11545 	      struct perf_event_context *parent_ctx,
11546 	      struct task_struct *child,
11547 	      struct perf_event *group_leader,
11548 	      struct perf_event_context *child_ctx)
11549 {
11550 	enum perf_event_state parent_state = parent_event->state;
11551 	struct perf_event *child_event;
11552 	unsigned long flags;
11553 
11554 	/*
11555 	 * Instead of creating recursive hierarchies of events,
11556 	 * we link inherited events back to the original parent,
11557 	 * which has a filp for sure, which we use as the reference
11558 	 * count:
11559 	 */
11560 	if (parent_event->parent)
11561 		parent_event = parent_event->parent;
11562 
11563 	child_event = perf_event_alloc(&parent_event->attr,
11564 					   parent_event->cpu,
11565 					   child,
11566 					   group_leader, parent_event,
11567 					   NULL, NULL, -1);
11568 	if (IS_ERR(child_event))
11569 		return child_event;
11570 
11571 
11572 	if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
11573 	    !child_ctx->task_ctx_data) {
11574 		struct pmu *pmu = child_event->pmu;
11575 
11576 		child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
11577 						   GFP_KERNEL);
11578 		if (!child_ctx->task_ctx_data) {
11579 			free_event(child_event);
11580 			return NULL;
11581 		}
11582 	}
11583 
11584 	/*
11585 	 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
11586 	 * must be under the same lock in order to serialize against
11587 	 * perf_event_release_kernel(), such that either we must observe
11588 	 * is_orphaned_event() or they will observe us on the child_list.
11589 	 */
11590 	mutex_lock(&parent_event->child_mutex);
11591 	if (is_orphaned_event(parent_event) ||
11592 	    !atomic_long_inc_not_zero(&parent_event->refcount)) {
11593 		mutex_unlock(&parent_event->child_mutex);
11594 		/* task_ctx_data is freed with child_ctx */
11595 		free_event(child_event);
11596 		return NULL;
11597 	}
11598 
11599 	get_ctx(child_ctx);
11600 
11601 	/*
11602 	 * Make the child state follow the state of the parent event,
11603 	 * not its attr.disabled bit.  We hold the parent's mutex,
11604 	 * so we won't race with perf_event_{en, dis}able_family.
11605 	 */
11606 	if (parent_state >= PERF_EVENT_STATE_INACTIVE)
11607 		child_event->state = PERF_EVENT_STATE_INACTIVE;
11608 	else
11609 		child_event->state = PERF_EVENT_STATE_OFF;
11610 
11611 	if (parent_event->attr.freq) {
11612 		u64 sample_period = parent_event->hw.sample_period;
11613 		struct hw_perf_event *hwc = &child_event->hw;
11614 
11615 		hwc->sample_period = sample_period;
11616 		hwc->last_period   = sample_period;
11617 
11618 		local64_set(&hwc->period_left, sample_period);
11619 	}
11620 
11621 	child_event->ctx = child_ctx;
11622 	child_event->overflow_handler = parent_event->overflow_handler;
11623 	child_event->overflow_handler_context
11624 		= parent_event->overflow_handler_context;
11625 
11626 	/*
11627 	 * Precalculate sample_data sizes
11628 	 */
11629 	perf_event__header_size(child_event);
11630 	perf_event__id_header_size(child_event);
11631 
11632 	/*
11633 	 * Link it up in the child's context:
11634 	 */
11635 	raw_spin_lock_irqsave(&child_ctx->lock, flags);
11636 	add_event_to_ctx(child_event, child_ctx);
11637 	raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
11638 
11639 	/*
11640 	 * Link this into the parent event's child list
11641 	 */
11642 	list_add_tail(&child_event->child_list, &parent_event->child_list);
11643 	mutex_unlock(&parent_event->child_mutex);
11644 
11645 	return child_event;
11646 }
11647 
11648 /*
11649  * Inherits an event group.
11650  *
11651  * This will quietly suppress orphaned events; !inherit_event() is not an error.
11652  * This matches with perf_event_release_kernel() removing all child events.
11653  *
11654  * Returns:
11655  *  - 0 on success
11656  *  - <0 on error
11657  */
11658 static int inherit_group(struct perf_event *parent_event,
11659 	      struct task_struct *parent,
11660 	      struct perf_event_context *parent_ctx,
11661 	      struct task_struct *child,
11662 	      struct perf_event_context *child_ctx)
11663 {
11664 	struct perf_event *leader;
11665 	struct perf_event *sub;
11666 	struct perf_event *child_ctr;
11667 
11668 	leader = inherit_event(parent_event, parent, parent_ctx,
11669 				 child, NULL, child_ctx);
11670 	if (IS_ERR(leader))
11671 		return PTR_ERR(leader);
11672 	/*
11673 	 * @leader can be NULL here because of is_orphaned_event(). In this
11674 	 * case inherit_event() will create individual events, similar to what
11675 	 * perf_group_detach() would do anyway.
11676 	 */
11677 	for_each_sibling_event(sub, parent_event) {
11678 		child_ctr = inherit_event(sub, parent, parent_ctx,
11679 					    child, leader, child_ctx);
11680 		if (IS_ERR(child_ctr))
11681 			return PTR_ERR(child_ctr);
11682 	}
11683 	return 0;
11684 }
11685 
11686 /*
11687  * Creates the child task context and tries to inherit the event-group.
11688  *
11689  * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
11690  * inherited_all set when we 'fail' to inherit an orphaned event; this is
11691  * consistent with perf_event_release_kernel() removing all child events.
11692  *
11693  * Returns:
11694  *  - 0 on success
11695  *  - <0 on error
11696  */
11697 static int
11698 inherit_task_group(struct perf_event *event, struct task_struct *parent,
11699 		   struct perf_event_context *parent_ctx,
11700 		   struct task_struct *child, int ctxn,
11701 		   int *inherited_all)
11702 {
11703 	int ret;
11704 	struct perf_event_context *child_ctx;
11705 
11706 	if (!event->attr.inherit) {
11707 		*inherited_all = 0;
11708 		return 0;
11709 	}
11710 
11711 	child_ctx = child->perf_event_ctxp[ctxn];
11712 	if (!child_ctx) {
11713 		/*
11714 		 * This is executed from the parent task context, so
11715 		 * inherit events that have been marked for cloning.
11716 		 * First allocate and initialize a context for the
11717 		 * child.
11718 		 */
11719 		child_ctx = alloc_perf_context(parent_ctx->pmu, child);
11720 		if (!child_ctx)
11721 			return -ENOMEM;
11722 
11723 		child->perf_event_ctxp[ctxn] = child_ctx;
11724 	}
11725 
11726 	ret = inherit_group(event, parent, parent_ctx,
11727 			    child, child_ctx);
11728 
11729 	if (ret)
11730 		*inherited_all = 0;
11731 
11732 	return ret;
11733 }
11734 
11735 /*
11736  * Initialize the perf_event context in task_struct
11737  */
11738 static int perf_event_init_context(struct task_struct *child, int ctxn)
11739 {
11740 	struct perf_event_context *child_ctx, *parent_ctx;
11741 	struct perf_event_context *cloned_ctx;
11742 	struct perf_event *event;
11743 	struct task_struct *parent = current;
11744 	int inherited_all = 1;
11745 	unsigned long flags;
11746 	int ret = 0;
11747 
11748 	if (likely(!parent->perf_event_ctxp[ctxn]))
11749 		return 0;
11750 
11751 	/*
11752 	 * If the parent's context is a clone, pin it so it won't get
11753 	 * swapped under us.
11754 	 */
11755 	parent_ctx = perf_pin_task_context(parent, ctxn);
11756 	if (!parent_ctx)
11757 		return 0;
11758 
11759 	/*
11760 	 * No need to check if parent_ctx != NULL here; since we saw
11761 	 * it non-NULL earlier, the only reason for it to become NULL
11762 	 * is if we exit, and since we're currently in the middle of
11763 	 * a fork we can't be exiting at the same time.
11764 	 */
11765 
11766 	/*
11767 	 * Lock the parent list. No need to lock the child - not PID
11768 	 * hashed yet and not running, so nobody can access it.
11769 	 */
11770 	mutex_lock(&parent_ctx->mutex);
11771 
11772 	/*
11773 	 * We dont have to disable NMIs - we are only looking at
11774 	 * the list, not manipulating it:
11775 	 */
11776 	perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
11777 		ret = inherit_task_group(event, parent, parent_ctx,
11778 					 child, ctxn, &inherited_all);
11779 		if (ret)
11780 			goto out_unlock;
11781 	}
11782 
11783 	/*
11784 	 * We can't hold ctx->lock when iterating the ->flexible_group list due
11785 	 * to allocations, but we need to prevent rotation because
11786 	 * rotate_ctx() will change the list from interrupt context.
11787 	 */
11788 	raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11789 	parent_ctx->rotate_disable = 1;
11790 	raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11791 
11792 	perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
11793 		ret = inherit_task_group(event, parent, parent_ctx,
11794 					 child, ctxn, &inherited_all);
11795 		if (ret)
11796 			goto out_unlock;
11797 	}
11798 
11799 	raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11800 	parent_ctx->rotate_disable = 0;
11801 
11802 	child_ctx = child->perf_event_ctxp[ctxn];
11803 
11804 	if (child_ctx && inherited_all) {
11805 		/*
11806 		 * Mark the child context as a clone of the parent
11807 		 * context, or of whatever the parent is a clone of.
11808 		 *
11809 		 * Note that if the parent is a clone, the holding of
11810 		 * parent_ctx->lock avoids it from being uncloned.
11811 		 */
11812 		cloned_ctx = parent_ctx->parent_ctx;
11813 		if (cloned_ctx) {
11814 			child_ctx->parent_ctx = cloned_ctx;
11815 			child_ctx->parent_gen = parent_ctx->parent_gen;
11816 		} else {
11817 			child_ctx->parent_ctx = parent_ctx;
11818 			child_ctx->parent_gen = parent_ctx->generation;
11819 		}
11820 		get_ctx(child_ctx->parent_ctx);
11821 	}
11822 
11823 	raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11824 out_unlock:
11825 	mutex_unlock(&parent_ctx->mutex);
11826 
11827 	perf_unpin_context(parent_ctx);
11828 	put_ctx(parent_ctx);
11829 
11830 	return ret;
11831 }
11832 
11833 /*
11834  * Initialize the perf_event context in task_struct
11835  */
11836 int perf_event_init_task(struct task_struct *child)
11837 {
11838 	int ctxn, ret;
11839 
11840 	memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
11841 	mutex_init(&child->perf_event_mutex);
11842 	INIT_LIST_HEAD(&child->perf_event_list);
11843 
11844 	for_each_task_context_nr(ctxn) {
11845 		ret = perf_event_init_context(child, ctxn);
11846 		if (ret) {
11847 			perf_event_free_task(child);
11848 			return ret;
11849 		}
11850 	}
11851 
11852 	return 0;
11853 }
11854 
11855 static void __init perf_event_init_all_cpus(void)
11856 {
11857 	struct swevent_htable *swhash;
11858 	int cpu;
11859 
11860 	zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
11861 
11862 	for_each_possible_cpu(cpu) {
11863 		swhash = &per_cpu(swevent_htable, cpu);
11864 		mutex_init(&swhash->hlist_mutex);
11865 		INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
11866 
11867 		INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
11868 		raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
11869 
11870 #ifdef CONFIG_CGROUP_PERF
11871 		INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
11872 #endif
11873 		INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
11874 	}
11875 }
11876 
11877 void perf_swevent_init_cpu(unsigned int cpu)
11878 {
11879 	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
11880 
11881 	mutex_lock(&swhash->hlist_mutex);
11882 	if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
11883 		struct swevent_hlist *hlist;
11884 
11885 		hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
11886 		WARN_ON(!hlist);
11887 		rcu_assign_pointer(swhash->swevent_hlist, hlist);
11888 	}
11889 	mutex_unlock(&swhash->hlist_mutex);
11890 }
11891 
11892 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11893 static void __perf_event_exit_context(void *__info)
11894 {
11895 	struct perf_event_context *ctx = __info;
11896 	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
11897 	struct perf_event *event;
11898 
11899 	raw_spin_lock(&ctx->lock);
11900 	ctx_sched_out(ctx, cpuctx, EVENT_TIME);
11901 	list_for_each_entry(event, &ctx->event_list, event_entry)
11902 		__perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
11903 	raw_spin_unlock(&ctx->lock);
11904 }
11905 
11906 static void perf_event_exit_cpu_context(int cpu)
11907 {
11908 	struct perf_cpu_context *cpuctx;
11909 	struct perf_event_context *ctx;
11910 	struct pmu *pmu;
11911 
11912 	mutex_lock(&pmus_lock);
11913 	list_for_each_entry(pmu, &pmus, entry) {
11914 		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11915 		ctx = &cpuctx->ctx;
11916 
11917 		mutex_lock(&ctx->mutex);
11918 		smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11919 		cpuctx->online = 0;
11920 		mutex_unlock(&ctx->mutex);
11921 	}
11922 	cpumask_clear_cpu(cpu, perf_online_mask);
11923 	mutex_unlock(&pmus_lock);
11924 }
11925 #else
11926 
11927 static void perf_event_exit_cpu_context(int cpu) { }
11928 
11929 #endif
11930 
11931 int perf_event_init_cpu(unsigned int cpu)
11932 {
11933 	struct perf_cpu_context *cpuctx;
11934 	struct perf_event_context *ctx;
11935 	struct pmu *pmu;
11936 
11937 	perf_swevent_init_cpu(cpu);
11938 
11939 	mutex_lock(&pmus_lock);
11940 	cpumask_set_cpu(cpu, perf_online_mask);
11941 	list_for_each_entry(pmu, &pmus, entry) {
11942 		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11943 		ctx = &cpuctx->ctx;
11944 
11945 		mutex_lock(&ctx->mutex);
11946 		cpuctx->online = 1;
11947 		mutex_unlock(&ctx->mutex);
11948 	}
11949 	mutex_unlock(&pmus_lock);
11950 
11951 	return 0;
11952 }
11953 
11954 int perf_event_exit_cpu(unsigned int cpu)
11955 {
11956 	perf_event_exit_cpu_context(cpu);
11957 	return 0;
11958 }
11959 
11960 static int
11961 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11962 {
11963 	int cpu;
11964 
11965 	for_each_online_cpu(cpu)
11966 		perf_event_exit_cpu(cpu);
11967 
11968 	return NOTIFY_OK;
11969 }
11970 
11971 /*
11972  * Run the perf reboot notifier at the very last possible moment so that
11973  * the generic watchdog code runs as long as possible.
11974  */
11975 static struct notifier_block perf_reboot_notifier = {
11976 	.notifier_call = perf_reboot,
11977 	.priority = INT_MIN,
11978 };
11979 
11980 void __init perf_event_init(void)
11981 {
11982 	int ret;
11983 
11984 	idr_init(&pmu_idr);
11985 
11986 	perf_event_init_all_cpus();
11987 	init_srcu_struct(&pmus_srcu);
11988 	perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11989 	perf_pmu_register(&perf_cpu_clock, NULL, -1);
11990 	perf_pmu_register(&perf_task_clock, NULL, -1);
11991 	perf_tp_register();
11992 	perf_event_init_cpu(smp_processor_id());
11993 	register_reboot_notifier(&perf_reboot_notifier);
11994 
11995 	ret = init_hw_breakpoint();
11996 	WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
11997 
11998 	/*
11999 	 * Build time assertion that we keep the data_head at the intended
12000 	 * location.  IOW, validation we got the __reserved[] size right.
12001 	 */
12002 	BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
12003 		     != 1024);
12004 }
12005 
12006 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
12007 			      char *page)
12008 {
12009 	struct perf_pmu_events_attr *pmu_attr =
12010 		container_of(attr, struct perf_pmu_events_attr, attr);
12011 
12012 	if (pmu_attr->event_str)
12013 		return sprintf(page, "%s\n", pmu_attr->event_str);
12014 
12015 	return 0;
12016 }
12017 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
12018 
12019 static int __init perf_event_sysfs_init(void)
12020 {
12021 	struct pmu *pmu;
12022 	int ret;
12023 
12024 	mutex_lock(&pmus_lock);
12025 
12026 	ret = bus_register(&pmu_bus);
12027 	if (ret)
12028 		goto unlock;
12029 
12030 	list_for_each_entry(pmu, &pmus, entry) {
12031 		if (!pmu->name || pmu->type < 0)
12032 			continue;
12033 
12034 		ret = pmu_dev_alloc(pmu);
12035 		WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
12036 	}
12037 	pmu_bus_running = 1;
12038 	ret = 0;
12039 
12040 unlock:
12041 	mutex_unlock(&pmus_lock);
12042 
12043 	return ret;
12044 }
12045 device_initcall(perf_event_sysfs_init);
12046 
12047 #ifdef CONFIG_CGROUP_PERF
12048 static struct cgroup_subsys_state *
12049 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
12050 {
12051 	struct perf_cgroup *jc;
12052 
12053 	jc = kzalloc(sizeof(*jc), GFP_KERNEL);
12054 	if (!jc)
12055 		return ERR_PTR(-ENOMEM);
12056 
12057 	jc->info = alloc_percpu(struct perf_cgroup_info);
12058 	if (!jc->info) {
12059 		kfree(jc);
12060 		return ERR_PTR(-ENOMEM);
12061 	}
12062 
12063 	return &jc->css;
12064 }
12065 
12066 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
12067 {
12068 	struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
12069 
12070 	free_percpu(jc->info);
12071 	kfree(jc);
12072 }
12073 
12074 static int __perf_cgroup_move(void *info)
12075 {
12076 	struct task_struct *task = info;
12077 	rcu_read_lock();
12078 	perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
12079 	rcu_read_unlock();
12080 	return 0;
12081 }
12082 
12083 static void perf_cgroup_attach(struct cgroup_taskset *tset)
12084 {
12085 	struct task_struct *task;
12086 	struct cgroup_subsys_state *css;
12087 
12088 	cgroup_taskset_for_each(task, css, tset)
12089 		task_function_call(task, __perf_cgroup_move, task);
12090 }
12091 
12092 struct cgroup_subsys perf_event_cgrp_subsys = {
12093 	.css_alloc	= perf_cgroup_css_alloc,
12094 	.css_free	= perf_cgroup_css_free,
12095 	.attach		= perf_cgroup_attach,
12096 	/*
12097 	 * Implicitly enable on dfl hierarchy so that perf events can
12098 	 * always be filtered by cgroup2 path as long as perf_event
12099 	 * controller is not mounted on a legacy hierarchy.
12100 	 */
12101 	.implicit_on_dfl = true,
12102 	.threaded	= true,
12103 };
12104 #endif /* CONFIG_CGROUP_PERF */
12105