1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * trace task wakeup timings
4  *
5  * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
6  * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
7  *
8  * Based on code from the latency_tracer, that is:
9  *
10  *  Copyright (C) 2004-2006 Ingo Molnar
11  *  Copyright (C) 2004 Nadia Yvette Chambers
12  */
13 #include <linux/module.h>
14 #include <linux/kallsyms.h>
15 #include <linux/uaccess.h>
16 #include <linux/ftrace.h>
17 #include <linux/sched/rt.h>
18 #include <linux/sched/deadline.h>
19 #include <trace/events/sched.h>
20 #include "trace.h"
21 
22 static struct trace_array	*wakeup_trace;
23 static int __read_mostly	tracer_enabled;
24 
25 static struct task_struct	*wakeup_task;
26 static int			wakeup_cpu;
27 static int			wakeup_current_cpu;
28 static unsigned			wakeup_prio = -1;
29 static bool			wakeup_rt;
30 static bool			wakeup_dl;
31 static bool			tracing_dl;
32 
33 static arch_spinlock_t wakeup_lock =
34 	(arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
35 
36 static void wakeup_reset(struct trace_array *tr);
37 static void __wakeup_reset(struct trace_array *tr);
38 static int start_func_tracer(struct trace_array *tr, int graph);
39 static void stop_func_tracer(struct trace_array *tr, int graph);
40 
41 static int save_flags;
42 
43 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
44 # define is_graph(tr) ((tr)->trace_flags & TRACE_ITER_DISPLAY_GRAPH)
45 #else
46 # define is_graph(tr) false
47 #endif
48 
49 #ifdef CONFIG_FUNCTION_TRACER
50 
51 static bool function_enabled;
52 
53 /*
54  * Prologue for the wakeup function tracers.
55  *
56  * Returns 1 if it is OK to continue, and preemption
57  *            is disabled and data->disabled is incremented.
58  *         0 if the trace is to be ignored, and preemption
59  *            is not disabled and data->disabled is
60  *            kept the same.
61  *
62  * Note, this function is also used outside this ifdef but
63  *  inside the #ifdef of the function graph tracer below.
64  *  This is OK, since the function graph tracer is
65  *  dependent on the function tracer.
66  */
67 static int
68 func_prolog_preempt_disable(struct trace_array *tr,
69 			    struct trace_array_cpu **data,
70 			    unsigned int *trace_ctx)
71 {
72 	long disabled;
73 	int cpu;
74 
75 	if (likely(!wakeup_task))
76 		return 0;
77 
78 	*trace_ctx = tracing_gen_ctx();
79 	preempt_disable_notrace();
80 
81 	cpu = raw_smp_processor_id();
82 	if (cpu != wakeup_current_cpu)
83 		goto out_enable;
84 
85 	*data = per_cpu_ptr(tr->array_buffer.data, cpu);
86 	disabled = atomic_inc_return(&(*data)->disabled);
87 	if (unlikely(disabled != 1))
88 		goto out;
89 
90 	return 1;
91 
92 out:
93 	atomic_dec(&(*data)->disabled);
94 
95 out_enable:
96 	preempt_enable_notrace();
97 	return 0;
98 }
99 
100 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
101 
102 static int wakeup_display_graph(struct trace_array *tr, int set)
103 {
104 	if (!(is_graph(tr) ^ set))
105 		return 0;
106 
107 	stop_func_tracer(tr, !set);
108 
109 	wakeup_reset(wakeup_trace);
110 	tr->max_latency = 0;
111 
112 	return start_func_tracer(tr, set);
113 }
114 
115 static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
116 {
117 	struct trace_array *tr = wakeup_trace;
118 	struct trace_array_cpu *data;
119 	unsigned int trace_ctx;
120 	int ret = 0;
121 
122 	if (ftrace_graph_ignore_func(trace))
123 		return 0;
124 	/*
125 	 * Do not trace a function if it's filtered by set_graph_notrace.
126 	 * Make the index of ret stack negative to indicate that it should
127 	 * ignore further functions.  But it needs its own ret stack entry
128 	 * to recover the original index in order to continue tracing after
129 	 * returning from the function.
130 	 */
131 	if (ftrace_graph_notrace_addr(trace->func))
132 		return 1;
133 
134 	if (!func_prolog_preempt_disable(tr, &data, &trace_ctx))
135 		return 0;
136 
137 	ret = __trace_graph_entry(tr, trace, trace_ctx);
138 	atomic_dec(&data->disabled);
139 	preempt_enable_notrace();
140 
141 	return ret;
142 }
143 
144 static void wakeup_graph_return(struct ftrace_graph_ret *trace)
145 {
146 	struct trace_array *tr = wakeup_trace;
147 	struct trace_array_cpu *data;
148 	unsigned int trace_ctx;
149 
150 	ftrace_graph_addr_finish(trace);
151 
152 	if (!func_prolog_preempt_disable(tr, &data, &trace_ctx))
153 		return;
154 
155 	__trace_graph_return(tr, trace, trace_ctx);
156 	atomic_dec(&data->disabled);
157 
158 	preempt_enable_notrace();
159 	return;
160 }
161 
162 static struct fgraph_ops fgraph_wakeup_ops = {
163 	.entryfunc = &wakeup_graph_entry,
164 	.retfunc = &wakeup_graph_return,
165 };
166 
167 static void wakeup_trace_open(struct trace_iterator *iter)
168 {
169 	if (is_graph(iter->tr))
170 		graph_trace_open(iter);
171 	else
172 		iter->private = NULL;
173 }
174 
175 static void wakeup_trace_close(struct trace_iterator *iter)
176 {
177 	if (iter->private)
178 		graph_trace_close(iter);
179 }
180 
181 #define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_PROC | \
182 			    TRACE_GRAPH_PRINT_CPU |  \
183 			    TRACE_GRAPH_PRINT_REL_TIME | \
184 			    TRACE_GRAPH_PRINT_DURATION | \
185 			    TRACE_GRAPH_PRINT_OVERHEAD | \
186 			    TRACE_GRAPH_PRINT_IRQS)
187 
188 static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
189 {
190 	/*
191 	 * In graph mode call the graph tracer output function,
192 	 * otherwise go with the TRACE_FN event handler
193 	 */
194 	if (is_graph(iter->tr))
195 		return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
196 
197 	return TRACE_TYPE_UNHANDLED;
198 }
199 
200 static void wakeup_print_header(struct seq_file *s)
201 {
202 	if (is_graph(wakeup_trace))
203 		print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
204 	else
205 		trace_default_header(s);
206 }
207 #endif /* else CONFIG_FUNCTION_GRAPH_TRACER */
208 
209 /*
210  * wakeup uses its own tracer function to keep the overhead down:
211  */
212 static void
213 wakeup_tracer_call(unsigned long ip, unsigned long parent_ip,
214 		   struct ftrace_ops *op, struct ftrace_regs *fregs)
215 {
216 	struct trace_array *tr = wakeup_trace;
217 	struct trace_array_cpu *data;
218 	unsigned long flags;
219 	unsigned int trace_ctx;
220 
221 	if (!func_prolog_preempt_disable(tr, &data, &trace_ctx))
222 		return;
223 
224 	local_irq_save(flags);
225 	trace_function(tr, ip, parent_ip, trace_ctx);
226 	local_irq_restore(flags);
227 
228 	atomic_dec(&data->disabled);
229 	preempt_enable_notrace();
230 }
231 
232 static int register_wakeup_function(struct trace_array *tr, int graph, int set)
233 {
234 	int ret;
235 
236 	/* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
237 	if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION)))
238 		return 0;
239 
240 	if (graph)
241 		ret = register_ftrace_graph(&fgraph_wakeup_ops);
242 	else
243 		ret = register_ftrace_function(tr->ops);
244 
245 	if (!ret)
246 		function_enabled = true;
247 
248 	return ret;
249 }
250 
251 static void unregister_wakeup_function(struct trace_array *tr, int graph)
252 {
253 	if (!function_enabled)
254 		return;
255 
256 	if (graph)
257 		unregister_ftrace_graph(&fgraph_wakeup_ops);
258 	else
259 		unregister_ftrace_function(tr->ops);
260 
261 	function_enabled = false;
262 }
263 
264 static int wakeup_function_set(struct trace_array *tr, u32 mask, int set)
265 {
266 	if (!(mask & TRACE_ITER_FUNCTION))
267 		return 0;
268 
269 	if (set)
270 		register_wakeup_function(tr, is_graph(tr), 1);
271 	else
272 		unregister_wakeup_function(tr, is_graph(tr));
273 	return 1;
274 }
275 #else /* CONFIG_FUNCTION_TRACER */
276 static int register_wakeup_function(struct trace_array *tr, int graph, int set)
277 {
278 	return 0;
279 }
280 static void unregister_wakeup_function(struct trace_array *tr, int graph) { }
281 static int wakeup_function_set(struct trace_array *tr, u32 mask, int set)
282 {
283 	return 0;
284 }
285 #endif /* else CONFIG_FUNCTION_TRACER */
286 
287 #ifndef CONFIG_FUNCTION_GRAPH_TRACER
288 static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
289 {
290 	return TRACE_TYPE_UNHANDLED;
291 }
292 
293 static void wakeup_trace_open(struct trace_iterator *iter) { }
294 static void wakeup_trace_close(struct trace_iterator *iter) { }
295 
296 static void wakeup_print_header(struct seq_file *s)
297 {
298 	trace_default_header(s);
299 }
300 #endif /* !CONFIG_FUNCTION_GRAPH_TRACER */
301 
302 static void
303 __trace_function(struct trace_array *tr,
304 		 unsigned long ip, unsigned long parent_ip,
305 		 unsigned int trace_ctx)
306 {
307 	if (is_graph(tr))
308 		trace_graph_function(tr, ip, parent_ip, trace_ctx);
309 	else
310 		trace_function(tr, ip, parent_ip, trace_ctx);
311 }
312 
313 static int wakeup_flag_changed(struct trace_array *tr, u32 mask, int set)
314 {
315 	struct tracer *tracer = tr->current_trace;
316 
317 	if (wakeup_function_set(tr, mask, set))
318 		return 0;
319 
320 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
321 	if (mask & TRACE_ITER_DISPLAY_GRAPH)
322 		return wakeup_display_graph(tr, set);
323 #endif
324 
325 	return trace_keep_overwrite(tracer, mask, set);
326 }
327 
328 static int start_func_tracer(struct trace_array *tr, int graph)
329 {
330 	int ret;
331 
332 	ret = register_wakeup_function(tr, graph, 0);
333 
334 	if (!ret && tracing_is_enabled())
335 		tracer_enabled = 1;
336 	else
337 		tracer_enabled = 0;
338 
339 	return ret;
340 }
341 
342 static void stop_func_tracer(struct trace_array *tr, int graph)
343 {
344 	tracer_enabled = 0;
345 
346 	unregister_wakeup_function(tr, graph);
347 }
348 
349 /*
350  * Should this new latency be reported/recorded?
351  */
352 static bool report_latency(struct trace_array *tr, u64 delta)
353 {
354 	if (tracing_thresh) {
355 		if (delta < tracing_thresh)
356 			return false;
357 	} else {
358 		if (delta <= tr->max_latency)
359 			return false;
360 	}
361 	return true;
362 }
363 
364 static void
365 probe_wakeup_migrate_task(void *ignore, struct task_struct *task, int cpu)
366 {
367 	if (task != wakeup_task)
368 		return;
369 
370 	wakeup_current_cpu = cpu;
371 }
372 
373 static void
374 tracing_sched_switch_trace(struct trace_array *tr,
375 			   struct task_struct *prev,
376 			   struct task_struct *next,
377 			   unsigned int trace_ctx)
378 {
379 	struct trace_event_call *call = &event_context_switch;
380 	struct trace_buffer *buffer = tr->array_buffer.buffer;
381 	struct ring_buffer_event *event;
382 	struct ctx_switch_entry *entry;
383 
384 	event = trace_buffer_lock_reserve(buffer, TRACE_CTX,
385 					  sizeof(*entry), trace_ctx);
386 	if (!event)
387 		return;
388 	entry	= ring_buffer_event_data(event);
389 	entry->prev_pid			= prev->pid;
390 	entry->prev_prio		= prev->prio;
391 	entry->prev_state		= task_state_index(prev);
392 	entry->next_pid			= next->pid;
393 	entry->next_prio		= next->prio;
394 	entry->next_state		= task_state_index(next);
395 	entry->next_cpu	= task_cpu(next);
396 
397 	if (!call_filter_check_discard(call, entry, buffer, event))
398 		trace_buffer_unlock_commit(tr, buffer, event, trace_ctx);
399 }
400 
401 static void
402 tracing_sched_wakeup_trace(struct trace_array *tr,
403 			   struct task_struct *wakee,
404 			   struct task_struct *curr,
405 			   unsigned int trace_ctx)
406 {
407 	struct trace_event_call *call = &event_wakeup;
408 	struct ring_buffer_event *event;
409 	struct ctx_switch_entry *entry;
410 	struct trace_buffer *buffer = tr->array_buffer.buffer;
411 
412 	event = trace_buffer_lock_reserve(buffer, TRACE_WAKE,
413 					  sizeof(*entry), trace_ctx);
414 	if (!event)
415 		return;
416 	entry	= ring_buffer_event_data(event);
417 	entry->prev_pid			= curr->pid;
418 	entry->prev_prio		= curr->prio;
419 	entry->prev_state		= task_state_index(curr);
420 	entry->next_pid			= wakee->pid;
421 	entry->next_prio		= wakee->prio;
422 	entry->next_state		= task_state_index(wakee);
423 	entry->next_cpu			= task_cpu(wakee);
424 
425 	if (!call_filter_check_discard(call, entry, buffer, event))
426 		trace_buffer_unlock_commit(tr, buffer, event, trace_ctx);
427 }
428 
429 static void notrace
430 probe_wakeup_sched_switch(void *ignore, bool preempt,
431 			  struct task_struct *prev, struct task_struct *next,
432 			  unsigned int prev_state)
433 {
434 	struct trace_array_cpu *data;
435 	u64 T0, T1, delta;
436 	unsigned long flags;
437 	long disabled;
438 	int cpu;
439 	unsigned int trace_ctx;
440 
441 	tracing_record_cmdline(prev);
442 
443 	if (unlikely(!tracer_enabled))
444 		return;
445 
446 	/*
447 	 * When we start a new trace, we set wakeup_task to NULL
448 	 * and then set tracer_enabled = 1. We want to make sure
449 	 * that another CPU does not see the tracer_enabled = 1
450 	 * and the wakeup_task with an older task, that might
451 	 * actually be the same as next.
452 	 */
453 	smp_rmb();
454 
455 	if (next != wakeup_task)
456 		return;
457 
458 	/* disable local data, not wakeup_cpu data */
459 	cpu = raw_smp_processor_id();
460 	disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
461 	if (likely(disabled != 1))
462 		goto out;
463 
464 	local_irq_save(flags);
465 	trace_ctx = tracing_gen_ctx_flags(flags);
466 
467 	arch_spin_lock(&wakeup_lock);
468 
469 	/* We could race with grabbing wakeup_lock */
470 	if (unlikely(!tracer_enabled || next != wakeup_task))
471 		goto out_unlock;
472 
473 	/* The task we are waiting for is waking up */
474 	data = per_cpu_ptr(wakeup_trace->array_buffer.data, wakeup_cpu);
475 
476 	__trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, trace_ctx);
477 	tracing_sched_switch_trace(wakeup_trace, prev, next, trace_ctx);
478 	__trace_stack(wakeup_trace, trace_ctx, 0);
479 
480 	T0 = data->preempt_timestamp;
481 	T1 = ftrace_now(cpu);
482 	delta = T1-T0;
483 
484 	if (!report_latency(wakeup_trace, delta))
485 		goto out_unlock;
486 
487 	if (likely(!is_tracing_stopped())) {
488 		wakeup_trace->max_latency = delta;
489 		update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu, NULL);
490 	}
491 
492 out_unlock:
493 	__wakeup_reset(wakeup_trace);
494 	arch_spin_unlock(&wakeup_lock);
495 	local_irq_restore(flags);
496 out:
497 	atomic_dec(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
498 }
499 
500 static void __wakeup_reset(struct trace_array *tr)
501 {
502 	wakeup_cpu = -1;
503 	wakeup_prio = -1;
504 	tracing_dl = false;
505 
506 	if (wakeup_task)
507 		put_task_struct(wakeup_task);
508 
509 	wakeup_task = NULL;
510 }
511 
512 static void wakeup_reset(struct trace_array *tr)
513 {
514 	unsigned long flags;
515 
516 	tracing_reset_online_cpus(&tr->array_buffer);
517 
518 	local_irq_save(flags);
519 	arch_spin_lock(&wakeup_lock);
520 	__wakeup_reset(tr);
521 	arch_spin_unlock(&wakeup_lock);
522 	local_irq_restore(flags);
523 }
524 
525 static void
526 probe_wakeup(void *ignore, struct task_struct *p)
527 {
528 	struct trace_array_cpu *data;
529 	int cpu = smp_processor_id();
530 	long disabled;
531 	unsigned int trace_ctx;
532 
533 	if (likely(!tracer_enabled))
534 		return;
535 
536 	tracing_record_cmdline(p);
537 	tracing_record_cmdline(current);
538 
539 	/*
540 	 * Semantic is like this:
541 	 *  - wakeup tracer handles all tasks in the system, independently
542 	 *    from their scheduling class;
543 	 *  - wakeup_rt tracer handles tasks belonging to sched_dl and
544 	 *    sched_rt class;
545 	 *  - wakeup_dl handles tasks belonging to sched_dl class only.
546 	 */
547 	if (tracing_dl || (wakeup_dl && !dl_task(p)) ||
548 	    (wakeup_rt && !dl_task(p) && !rt_task(p)) ||
549 	    (!dl_task(p) && (p->prio >= wakeup_prio || p->prio >= current->prio)))
550 		return;
551 
552 	disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
553 	if (unlikely(disabled != 1))
554 		goto out;
555 
556 	trace_ctx = tracing_gen_ctx();
557 
558 	/* interrupts should be off from try_to_wake_up */
559 	arch_spin_lock(&wakeup_lock);
560 
561 	/* check for races. */
562 	if (!tracer_enabled || tracing_dl ||
563 	    (!dl_task(p) && p->prio >= wakeup_prio))
564 		goto out_locked;
565 
566 	/* reset the trace */
567 	__wakeup_reset(wakeup_trace);
568 
569 	wakeup_cpu = task_cpu(p);
570 	wakeup_current_cpu = wakeup_cpu;
571 	wakeup_prio = p->prio;
572 
573 	/*
574 	 * Once you start tracing a -deadline task, don't bother tracing
575 	 * another task until the first one wakes up.
576 	 */
577 	if (dl_task(p))
578 		tracing_dl = true;
579 	else
580 		tracing_dl = false;
581 
582 	wakeup_task = get_task_struct(p);
583 
584 	data = per_cpu_ptr(wakeup_trace->array_buffer.data, wakeup_cpu);
585 	data->preempt_timestamp = ftrace_now(cpu);
586 	tracing_sched_wakeup_trace(wakeup_trace, p, current, trace_ctx);
587 	__trace_stack(wakeup_trace, trace_ctx, 0);
588 
589 	/*
590 	 * We must be careful in using CALLER_ADDR2. But since wake_up
591 	 * is not called by an assembly function  (where as schedule is)
592 	 * it should be safe to use it here.
593 	 */
594 	__trace_function(wakeup_trace, CALLER_ADDR1, CALLER_ADDR2, trace_ctx);
595 
596 out_locked:
597 	arch_spin_unlock(&wakeup_lock);
598 out:
599 	atomic_dec(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
600 }
601 
602 static void start_wakeup_tracer(struct trace_array *tr)
603 {
604 	int ret;
605 
606 	ret = register_trace_sched_wakeup(probe_wakeup, NULL);
607 	if (ret) {
608 		pr_info("wakeup trace: Couldn't activate tracepoint"
609 			" probe to kernel_sched_wakeup\n");
610 		return;
611 	}
612 
613 	ret = register_trace_sched_wakeup_new(probe_wakeup, NULL);
614 	if (ret) {
615 		pr_info("wakeup trace: Couldn't activate tracepoint"
616 			" probe to kernel_sched_wakeup_new\n");
617 		goto fail_deprobe;
618 	}
619 
620 	ret = register_trace_sched_switch(probe_wakeup_sched_switch, NULL);
621 	if (ret) {
622 		pr_info("sched trace: Couldn't activate tracepoint"
623 			" probe to kernel_sched_switch\n");
624 		goto fail_deprobe_wake_new;
625 	}
626 
627 	ret = register_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
628 	if (ret) {
629 		pr_info("wakeup trace: Couldn't activate tracepoint"
630 			" probe to kernel_sched_migrate_task\n");
631 		goto fail_deprobe_sched_switch;
632 	}
633 
634 	wakeup_reset(tr);
635 
636 	/*
637 	 * Don't let the tracer_enabled = 1 show up before
638 	 * the wakeup_task is reset. This may be overkill since
639 	 * wakeup_reset does a spin_unlock after setting the
640 	 * wakeup_task to NULL, but I want to be safe.
641 	 * This is a slow path anyway.
642 	 */
643 	smp_wmb();
644 
645 	if (start_func_tracer(tr, is_graph(tr)))
646 		printk(KERN_ERR "failed to start wakeup tracer\n");
647 
648 	return;
649 fail_deprobe_sched_switch:
650 	unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
651 fail_deprobe_wake_new:
652 	unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
653 fail_deprobe:
654 	unregister_trace_sched_wakeup(probe_wakeup, NULL);
655 }
656 
657 static void stop_wakeup_tracer(struct trace_array *tr)
658 {
659 	tracer_enabled = 0;
660 	stop_func_tracer(tr, is_graph(tr));
661 	unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
662 	unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
663 	unregister_trace_sched_wakeup(probe_wakeup, NULL);
664 	unregister_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
665 }
666 
667 static bool wakeup_busy;
668 
669 static int __wakeup_tracer_init(struct trace_array *tr)
670 {
671 	save_flags = tr->trace_flags;
672 
673 	/* non overwrite screws up the latency tracers */
674 	set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
675 	set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
676 
677 	tr->max_latency = 0;
678 	wakeup_trace = tr;
679 	ftrace_init_array_ops(tr, wakeup_tracer_call);
680 	start_wakeup_tracer(tr);
681 
682 	wakeup_busy = true;
683 	return 0;
684 }
685 
686 static int wakeup_tracer_init(struct trace_array *tr)
687 {
688 	if (wakeup_busy)
689 		return -EBUSY;
690 
691 	wakeup_dl = false;
692 	wakeup_rt = false;
693 	return __wakeup_tracer_init(tr);
694 }
695 
696 static int wakeup_rt_tracer_init(struct trace_array *tr)
697 {
698 	if (wakeup_busy)
699 		return -EBUSY;
700 
701 	wakeup_dl = false;
702 	wakeup_rt = true;
703 	return __wakeup_tracer_init(tr);
704 }
705 
706 static int wakeup_dl_tracer_init(struct trace_array *tr)
707 {
708 	if (wakeup_busy)
709 		return -EBUSY;
710 
711 	wakeup_dl = true;
712 	wakeup_rt = false;
713 	return __wakeup_tracer_init(tr);
714 }
715 
716 static void wakeup_tracer_reset(struct trace_array *tr)
717 {
718 	int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
719 	int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
720 
721 	stop_wakeup_tracer(tr);
722 	/* make sure we put back any tasks we are tracing */
723 	wakeup_reset(tr);
724 
725 	set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
726 	set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
727 	ftrace_reset_array_ops(tr);
728 	wakeup_busy = false;
729 }
730 
731 static void wakeup_tracer_start(struct trace_array *tr)
732 {
733 	wakeup_reset(tr);
734 	tracer_enabled = 1;
735 }
736 
737 static void wakeup_tracer_stop(struct trace_array *tr)
738 {
739 	tracer_enabled = 0;
740 }
741 
742 static struct tracer wakeup_tracer __read_mostly =
743 {
744 	.name		= "wakeup",
745 	.init		= wakeup_tracer_init,
746 	.reset		= wakeup_tracer_reset,
747 	.start		= wakeup_tracer_start,
748 	.stop		= wakeup_tracer_stop,
749 	.print_max	= true,
750 	.print_header	= wakeup_print_header,
751 	.print_line	= wakeup_print_line,
752 	.flag_changed	= wakeup_flag_changed,
753 #ifdef CONFIG_FTRACE_SELFTEST
754 	.selftest    = trace_selftest_startup_wakeup,
755 #endif
756 	.open		= wakeup_trace_open,
757 	.close		= wakeup_trace_close,
758 	.allow_instances = true,
759 	.use_max_tr	= true,
760 };
761 
762 static struct tracer wakeup_rt_tracer __read_mostly =
763 {
764 	.name		= "wakeup_rt",
765 	.init		= wakeup_rt_tracer_init,
766 	.reset		= wakeup_tracer_reset,
767 	.start		= wakeup_tracer_start,
768 	.stop		= wakeup_tracer_stop,
769 	.print_max	= true,
770 	.print_header	= wakeup_print_header,
771 	.print_line	= wakeup_print_line,
772 	.flag_changed	= wakeup_flag_changed,
773 #ifdef CONFIG_FTRACE_SELFTEST
774 	.selftest    = trace_selftest_startup_wakeup,
775 #endif
776 	.open		= wakeup_trace_open,
777 	.close		= wakeup_trace_close,
778 	.allow_instances = true,
779 	.use_max_tr	= true,
780 };
781 
782 static struct tracer wakeup_dl_tracer __read_mostly =
783 {
784 	.name		= "wakeup_dl",
785 	.init		= wakeup_dl_tracer_init,
786 	.reset		= wakeup_tracer_reset,
787 	.start		= wakeup_tracer_start,
788 	.stop		= wakeup_tracer_stop,
789 	.print_max	= true,
790 	.print_header	= wakeup_print_header,
791 	.print_line	= wakeup_print_line,
792 	.flag_changed	= wakeup_flag_changed,
793 #ifdef CONFIG_FTRACE_SELFTEST
794 	.selftest    = trace_selftest_startup_wakeup,
795 #endif
796 	.open		= wakeup_trace_open,
797 	.close		= wakeup_trace_close,
798 	.allow_instances = true,
799 	.use_max_tr	= true,
800 };
801 
802 __init static int init_wakeup_tracer(void)
803 {
804 	int ret;
805 
806 	ret = register_tracer(&wakeup_tracer);
807 	if (ret)
808 		return ret;
809 
810 	ret = register_tracer(&wakeup_rt_tracer);
811 	if (ret)
812 		return ret;
813 
814 	ret = register_tracer(&wakeup_dl_tracer);
815 	if (ret)
816 		return ret;
817 
818 	return 0;
819 }
820 core_initcall(init_wakeup_tracer);
821