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