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			      struct fgraph_ops *gops)
117{
118	struct trace_array *tr = wakeup_trace;
119	struct trace_array_cpu *data;
120	unsigned int trace_ctx;
121	u64 *calltime;
122	int ret = 0;
123
124	if (ftrace_graph_ignore_func(gops, trace))
125		return 0;
126	/*
127	 * Do not trace a function if it's filtered by set_graph_notrace.
128	 * Make the index of ret stack negative to indicate that it should
129	 * ignore further functions.  But it needs its own ret stack entry
130	 * to recover the original index in order to continue tracing after
131	 * returning from the function.
132	 */
133	if (ftrace_graph_notrace_addr(trace->func))
134		return 1;
135
136	if (!func_prolog_preempt_disable(tr, &data, &trace_ctx))
137		return 0;
138
139	calltime = fgraph_reserve_data(gops->idx, sizeof(*calltime));
140	if (!calltime)
141		return 0;
142
143	*calltime = trace_clock_local();
144
145	ret = __trace_graph_entry(tr, trace, trace_ctx);
146	atomic_dec(&data->disabled);
147	preempt_enable_notrace();
148
149	return ret;
150}
151
152static void wakeup_graph_return(struct ftrace_graph_ret *trace,
153				struct fgraph_ops *gops)
154{
155	struct trace_array *tr = wakeup_trace;
156	struct trace_array_cpu *data;
157	unsigned int trace_ctx;
158	u64 *calltime;
159	int size;
160
161	ftrace_graph_addr_finish(gops, trace);
162
163	if (!func_prolog_preempt_disable(tr, &data, &trace_ctx))
164		return;
165
166	calltime = fgraph_retrieve_data(gops->idx, &size);
167	if (!calltime)
168		return;
169	trace->calltime = *calltime;
170
171	__trace_graph_return(tr, trace, trace_ctx);
 
172	atomic_dec(&data->disabled);
173
174	preempt_enable_notrace();
175	return;
176}
177
178static struct fgraph_ops fgraph_wakeup_ops = {
179	.entryfunc = &wakeup_graph_entry,
180	.retfunc = &wakeup_graph_return,
181};
182
183static void wakeup_trace_open(struct trace_iterator *iter)
184{
185	if (is_graph(iter->tr))
186		graph_trace_open(iter);
187	else
188		iter->private = NULL;
189}
190
191static void wakeup_trace_close(struct trace_iterator *iter)
192{
193	if (iter->private)
194		graph_trace_close(iter);
195}
196
197#define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_PROC | \
198			    TRACE_GRAPH_PRINT_CPU |  \
199			    TRACE_GRAPH_PRINT_REL_TIME | \
200			    TRACE_GRAPH_PRINT_DURATION | \
201			    TRACE_GRAPH_PRINT_OVERHEAD | \
202			    TRACE_GRAPH_PRINT_IRQS)
203
204static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
205{
206	/*
207	 * In graph mode call the graph tracer output function,
208	 * otherwise go with the TRACE_FN event handler
209	 */
210	if (is_graph(iter->tr))
211		return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
212
213	return TRACE_TYPE_UNHANDLED;
214}
215
216static void wakeup_print_header(struct seq_file *s)
217{
218	if (is_graph(wakeup_trace))
219		print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
220	else
221		trace_default_header(s);
222}
223#endif /* else CONFIG_FUNCTION_GRAPH_TRACER */
224
225/*
226 * wakeup uses its own tracer function to keep the overhead down:
227 */
228static void
229wakeup_tracer_call(unsigned long ip, unsigned long parent_ip,
230		   struct ftrace_ops *op, struct ftrace_regs *fregs)
231{
232	struct trace_array *tr = wakeup_trace;
233	struct trace_array_cpu *data;
234	unsigned long flags;
235	unsigned int trace_ctx;
236
237	if (!func_prolog_preempt_disable(tr, &data, &trace_ctx))
238		return;
239
240	local_irq_save(flags);
241	trace_function(tr, ip, parent_ip, trace_ctx);
242	local_irq_restore(flags);
243
244	atomic_dec(&data->disabled);
245	preempt_enable_notrace();
246}
247
248static int register_wakeup_function(struct trace_array *tr, int graph, int set)
249{
250	int ret;
251
252	/* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
253	if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION)))
254		return 0;
255
256	if (graph)
257		ret = register_ftrace_graph(&fgraph_wakeup_ops);
258	else
259		ret = register_ftrace_function(tr->ops);
260
261	if (!ret)
262		function_enabled = true;
263
264	return ret;
265}
 
 
266
267static void unregister_wakeup_function(struct trace_array *tr, int graph)
268{
269	if (!function_enabled)
270		return;
271
272	if (graph)
273		unregister_ftrace_graph(&fgraph_wakeup_ops);
274	else
275		unregister_ftrace_function(tr->ops);
276
277	function_enabled = false;
278}
279
280static int wakeup_function_set(struct trace_array *tr, u32 mask, int set)
281{
282	if (!(mask & TRACE_ITER_FUNCTION))
283		return 0;
284
285	if (set)
286		register_wakeup_function(tr, is_graph(tr), 1);
287	else
288		unregister_wakeup_function(tr, is_graph(tr));
289	return 1;
290}
291#else /* CONFIG_FUNCTION_TRACER */
292static int register_wakeup_function(struct trace_array *tr, int graph, int set)
293{
294	return 0;
295}
296static void unregister_wakeup_function(struct trace_array *tr, int graph) { }
297static int wakeup_function_set(struct trace_array *tr, u32 mask, int set)
298{
299	return 0;
300}
301#endif /* else CONFIG_FUNCTION_TRACER */
302
303#ifndef CONFIG_FUNCTION_GRAPH_TRACER
304static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
305{
306	return TRACE_TYPE_UNHANDLED;
307}
308
 
 
309static void wakeup_trace_open(struct trace_iterator *iter) { }
310static void wakeup_trace_close(struct trace_iterator *iter) { }
311
312static void wakeup_print_header(struct seq_file *s)
313{
314	trace_default_header(s);
315}
316#endif /* !CONFIG_FUNCTION_GRAPH_TRACER */
317
318static void
319__trace_function(struct trace_array *tr,
320		 unsigned long ip, unsigned long parent_ip,
321		 unsigned int trace_ctx)
322{
323	if (is_graph(tr))
324		trace_graph_function(tr, ip, parent_ip, trace_ctx);
325	else
326		trace_function(tr, ip, parent_ip, trace_ctx);
327}
328
329static int wakeup_flag_changed(struct trace_array *tr, u32 mask, int set)
330{
331	struct tracer *tracer = tr->current_trace;
332
333	if (wakeup_function_set(tr, mask, set))
334		return 0;
335
336#ifdef CONFIG_FUNCTION_GRAPH_TRACER
337	if (mask & TRACE_ITER_DISPLAY_GRAPH)
338		return wakeup_display_graph(tr, set);
339#endif
340
341	return trace_keep_overwrite(tracer, mask, set);
342}
343
344static int start_func_tracer(struct trace_array *tr, int graph)
345{
346	int ret;
347
348	ret = register_wakeup_function(tr, graph, 0);
349
350	if (!ret && tracing_is_enabled())
351		tracer_enabled = 1;
352	else
353		tracer_enabled = 0;
354
355	return ret;
356}
357
358static void stop_func_tracer(struct trace_array *tr, int graph)
359{
360	tracer_enabled = 0;
361
362	unregister_wakeup_function(tr, graph);
363}
364
365/*
366 * Should this new latency be reported/recorded?
367 */
368static bool report_latency(struct trace_array *tr, u64 delta)
369{
370	if (tracing_thresh) {
371		if (delta < tracing_thresh)
372			return false;
373	} else {
374		if (delta <= tr->max_latency)
375			return false;
376	}
377	return true;
378}
379
380static void
381probe_wakeup_migrate_task(void *ignore, struct task_struct *task, int cpu)
382{
383	if (task != wakeup_task)
384		return;
385
386	wakeup_current_cpu = cpu;
387}
388
389static void
390tracing_sched_switch_trace(struct trace_array *tr,
391			   struct task_struct *prev,
392			   struct task_struct *next,
393			   unsigned int trace_ctx)
394{
395	struct trace_buffer *buffer = tr->array_buffer.buffer;
396	struct ring_buffer_event *event;
397	struct ctx_switch_entry *entry;
398
399	event = trace_buffer_lock_reserve(buffer, TRACE_CTX,
400					  sizeof(*entry), trace_ctx);
401	if (!event)
402		return;
403	entry	= ring_buffer_event_data(event);
404	entry->prev_pid			= prev->pid;
405	entry->prev_prio		= prev->prio;
406	entry->prev_state		= task_state_index(prev);
407	entry->next_pid			= next->pid;
408	entry->next_prio		= next->prio;
409	entry->next_state		= task_state_index(next);
410	entry->next_cpu	= task_cpu(next);
411
412	trace_buffer_unlock_commit(tr, buffer, event, trace_ctx);
413}
414
415static void
416tracing_sched_wakeup_trace(struct trace_array *tr,
417			   struct task_struct *wakee,
418			   struct task_struct *curr,
419			   unsigned int trace_ctx)
420{
421	struct ring_buffer_event *event;
422	struct ctx_switch_entry *entry;
423	struct trace_buffer *buffer = tr->array_buffer.buffer;
424
425	event = trace_buffer_lock_reserve(buffer, TRACE_WAKE,
426					  sizeof(*entry), trace_ctx);
427	if (!event)
428		return;
429	entry	= ring_buffer_event_data(event);
430	entry->prev_pid			= curr->pid;
431	entry->prev_prio		= curr->prio;
432	entry->prev_state		= task_state_index(curr);
433	entry->next_pid			= wakee->pid;
434	entry->next_prio		= wakee->prio;
435	entry->next_state		= task_state_index(wakee);
436	entry->next_cpu			= task_cpu(wakee);
437
438	trace_buffer_unlock_commit(tr, buffer, event, trace_ctx);
439}
440
441static void notrace
442probe_wakeup_sched_switch(void *ignore, bool preempt,
443			  struct task_struct *prev, struct task_struct *next,
444			  unsigned int prev_state)
445{
446	struct trace_array_cpu *data;
447	u64 T0, T1, delta;
448	unsigned long flags;
449	long disabled;
450	int cpu;
451	unsigned int trace_ctx;
452
453	tracing_record_cmdline(prev);
454
455	if (unlikely(!tracer_enabled))
456		return;
457
458	/*
459	 * When we start a new trace, we set wakeup_task to NULL
460	 * and then set tracer_enabled = 1. We want to make sure
461	 * that another CPU does not see the tracer_enabled = 1
462	 * and the wakeup_task with an older task, that might
463	 * actually be the same as next.
464	 */
465	smp_rmb();
466
467	if (next != wakeup_task)
468		return;
469
 
 
470	/* disable local data, not wakeup_cpu data */
471	cpu = raw_smp_processor_id();
472	disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
473	if (likely(disabled != 1))
474		goto out;
475
476	local_irq_save(flags);
477	trace_ctx = tracing_gen_ctx_flags(flags);
478
479	arch_spin_lock(&wakeup_lock);
480
481	/* We could race with grabbing wakeup_lock */
482	if (unlikely(!tracer_enabled || next != wakeup_task))
483		goto out_unlock;
484
485	/* The task we are waiting for is waking up */
486	data = per_cpu_ptr(wakeup_trace->array_buffer.data, wakeup_cpu);
487
488	__trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, trace_ctx);
489	tracing_sched_switch_trace(wakeup_trace, prev, next, trace_ctx);
490	__trace_stack(wakeup_trace, trace_ctx, 0);
491
492	T0 = data->preempt_timestamp;
493	T1 = ftrace_now(cpu);
494	delta = T1-T0;
495
496	if (!report_latency(wakeup_trace, delta))
497		goto out_unlock;
498
499	if (likely(!is_tracing_stopped())) {
500		wakeup_trace->max_latency = delta;
501		update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu, NULL);
502	}
503
504out_unlock:
505	__wakeup_reset(wakeup_trace);
506	arch_spin_unlock(&wakeup_lock);
507	local_irq_restore(flags);
508out:
509	atomic_dec(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
510}
511
512static void __wakeup_reset(struct trace_array *tr)
513{
514	wakeup_cpu = -1;
515	wakeup_prio = -1;
516	tracing_dl = false;
517
518	if (wakeup_task)
519		put_task_struct(wakeup_task);
520
521	wakeup_task = NULL;
522}
523
524static void wakeup_reset(struct trace_array *tr)
525{
526	unsigned long flags;
527
528	tracing_reset_online_cpus(&tr->array_buffer);
529
530	local_irq_save(flags);
531	arch_spin_lock(&wakeup_lock);
532	__wakeup_reset(tr);
533	arch_spin_unlock(&wakeup_lock);
534	local_irq_restore(flags);
535}
536
537static void
538probe_wakeup(void *ignore, struct task_struct *p)
539{
540	struct trace_array_cpu *data;
541	int cpu = smp_processor_id();
 
542	long disabled;
543	unsigned int trace_ctx;
544
545	if (likely(!tracer_enabled))
546		return;
547
548	tracing_record_cmdline(p);
549	tracing_record_cmdline(current);
550
551	/*
552	 * Semantic is like this:
553	 *  - wakeup tracer handles all tasks in the system, independently
554	 *    from their scheduling class;
555	 *  - wakeup_rt tracer handles tasks belonging to sched_dl and
556	 *    sched_rt class;
557	 *  - wakeup_dl handles tasks belonging to sched_dl class only.
558	 */
559	if (tracing_dl || (wakeup_dl && !dl_task(p)) ||
560	    (wakeup_rt && !rt_or_dl_task(p)) ||
561	    (!dl_task(p) && (p->prio >= wakeup_prio || p->prio >= current->prio)))
562		return;
563
564	disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
 
565	if (unlikely(disabled != 1))
566		goto out;
567
568	trace_ctx = tracing_gen_ctx();
569
570	/* interrupts should be off from try_to_wake_up */
571	arch_spin_lock(&wakeup_lock);
572
573	/* check for races. */
574	if (!tracer_enabled || tracing_dl ||
575	    (!dl_task(p) && p->prio >= wakeup_prio))
576		goto out_locked;
577
578	/* reset the trace */
579	__wakeup_reset(wakeup_trace);
580
581	wakeup_cpu = task_cpu(p);
582	wakeup_current_cpu = wakeup_cpu;
583	wakeup_prio = p->prio;
584
585	/*
586	 * Once you start tracing a -deadline task, don't bother tracing
587	 * another task until the first one wakes up.
588	 */
589	if (dl_task(p))
590		tracing_dl = true;
591	else
592		tracing_dl = false;
593
594	wakeup_task = get_task_struct(p);
595
596	data = per_cpu_ptr(wakeup_trace->array_buffer.data, wakeup_cpu);
597	data->preempt_timestamp = ftrace_now(cpu);
598	tracing_sched_wakeup_trace(wakeup_trace, p, current, trace_ctx);
599	__trace_stack(wakeup_trace, trace_ctx, 0);
600
601	/*
602	 * We must be careful in using CALLER_ADDR2. But since wake_up
603	 * is not called by an assembly function  (where as schedule is)
604	 * it should be safe to use it here.
605	 */
606	__trace_function(wakeup_trace, CALLER_ADDR1, CALLER_ADDR2, trace_ctx);
607
608out_locked:
609	arch_spin_unlock(&wakeup_lock);
610out:
611	atomic_dec(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
612}
613
614static void start_wakeup_tracer(struct trace_array *tr)
615{
616	int ret;
617
618	ret = register_trace_sched_wakeup(probe_wakeup, NULL);
619	if (ret) {
620		pr_info("wakeup trace: Couldn't activate tracepoint"
621			" probe to kernel_sched_wakeup\n");
622		return;
623	}
624
625	ret = register_trace_sched_wakeup_new(probe_wakeup, NULL);
626	if (ret) {
627		pr_info("wakeup trace: Couldn't activate tracepoint"
628			" probe to kernel_sched_wakeup_new\n");
629		goto fail_deprobe;
630	}
631
632	ret = register_trace_sched_switch(probe_wakeup_sched_switch, NULL);
633	if (ret) {
634		pr_info("sched trace: Couldn't activate tracepoint"
635			" probe to kernel_sched_switch\n");
636		goto fail_deprobe_wake_new;
637	}
638
639	ret = register_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
640	if (ret) {
641		pr_info("wakeup trace: Couldn't activate tracepoint"
642			" probe to kernel_sched_migrate_task\n");
643		goto fail_deprobe_sched_switch;
644	}
645
646	wakeup_reset(tr);
647
648	/*
649	 * Don't let the tracer_enabled = 1 show up before
650	 * the wakeup_task is reset. This may be overkill since
651	 * wakeup_reset does a spin_unlock after setting the
652	 * wakeup_task to NULL, but I want to be safe.
653	 * This is a slow path anyway.
654	 */
655	smp_wmb();
656
657	if (start_func_tracer(tr, is_graph(tr)))
658		printk(KERN_ERR "failed to start wakeup tracer\n");
659
660	return;
661fail_deprobe_sched_switch:
662	unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
663fail_deprobe_wake_new:
664	unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
665fail_deprobe:
666	unregister_trace_sched_wakeup(probe_wakeup, NULL);
667}
668
669static void stop_wakeup_tracer(struct trace_array *tr)
670{
671	tracer_enabled = 0;
672	stop_func_tracer(tr, is_graph(tr));
673	unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
674	unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
675	unregister_trace_sched_wakeup(probe_wakeup, NULL);
676	unregister_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
677}
678
679static bool wakeup_busy;
680
681static int __wakeup_tracer_init(struct trace_array *tr)
682{
683	save_flags = tr->trace_flags;
684
685	/* non overwrite screws up the latency tracers */
686	set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
687	set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
688
689	tr->max_latency = 0;
690	wakeup_trace = tr;
691	ftrace_init_array_ops(tr, wakeup_tracer_call);
692	start_wakeup_tracer(tr);
693
694	wakeup_busy = true;
695	return 0;
696}
697
698static int wakeup_tracer_init(struct trace_array *tr)
699{
700	if (wakeup_busy)
701		return -EBUSY;
702
703	wakeup_dl = false;
704	wakeup_rt = false;
705	return __wakeup_tracer_init(tr);
706}
707
708static int wakeup_rt_tracer_init(struct trace_array *tr)
709{
710	if (wakeup_busy)
711		return -EBUSY;
712
713	wakeup_dl = false;
714	wakeup_rt = true;
715	return __wakeup_tracer_init(tr);
716}
717
718static int wakeup_dl_tracer_init(struct trace_array *tr)
719{
720	if (wakeup_busy)
721		return -EBUSY;
722
723	wakeup_dl = true;
724	wakeup_rt = false;
725	return __wakeup_tracer_init(tr);
726}
727
728static void wakeup_tracer_reset(struct trace_array *tr)
729{
730	int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
731	int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
732
733	stop_wakeup_tracer(tr);
734	/* make sure we put back any tasks we are tracing */
735	wakeup_reset(tr);
736
737	set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
738	set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
739	ftrace_reset_array_ops(tr);
740	wakeup_busy = false;
741}
742
743static void wakeup_tracer_start(struct trace_array *tr)
744{
745	wakeup_reset(tr);
746	tracer_enabled = 1;
747}
748
749static void wakeup_tracer_stop(struct trace_array *tr)
750{
751	tracer_enabled = 0;
752}
753
754static struct tracer wakeup_tracer __read_mostly =
755{
756	.name		= "wakeup",
757	.init		= wakeup_tracer_init,
758	.reset		= wakeup_tracer_reset,
759	.start		= wakeup_tracer_start,
760	.stop		= wakeup_tracer_stop,
761	.print_max	= true,
762	.print_header	= wakeup_print_header,
763	.print_line	= wakeup_print_line,
764	.flag_changed	= wakeup_flag_changed,
 
765#ifdef CONFIG_FTRACE_SELFTEST
766	.selftest    = trace_selftest_startup_wakeup,
767#endif
768	.open		= wakeup_trace_open,
769	.close		= wakeup_trace_close,
770	.allow_instances = true,
771	.use_max_tr	= true,
772};
773
774static struct tracer wakeup_rt_tracer __read_mostly =
775{
776	.name		= "wakeup_rt",
777	.init		= wakeup_rt_tracer_init,
778	.reset		= wakeup_tracer_reset,
779	.start		= wakeup_tracer_start,
780	.stop		= wakeup_tracer_stop,
781	.print_max	= true,
782	.print_header	= wakeup_print_header,
783	.print_line	= wakeup_print_line,
784	.flag_changed	= wakeup_flag_changed,
785#ifdef CONFIG_FTRACE_SELFTEST
786	.selftest    = trace_selftest_startup_wakeup,
787#endif
788	.open		= wakeup_trace_open,
789	.close		= wakeup_trace_close,
790	.allow_instances = true,
791	.use_max_tr	= true,
792};
793
794static struct tracer wakeup_dl_tracer __read_mostly =
795{
796	.name		= "wakeup_dl",
797	.init		= wakeup_dl_tracer_init,
798	.reset		= wakeup_tracer_reset,
799	.start		= wakeup_tracer_start,
800	.stop		= wakeup_tracer_stop,
801	.print_max	= true,
802	.print_header	= wakeup_print_header,
803	.print_line	= wakeup_print_line,
804	.flag_changed	= wakeup_flag_changed,
 
805#ifdef CONFIG_FTRACE_SELFTEST
806	.selftest    = trace_selftest_startup_wakeup,
807#endif
808	.open		= wakeup_trace_open,
809	.close		= wakeup_trace_close,
810	.allow_instances = true,
811	.use_max_tr	= true,
812};
813
814__init static int init_wakeup_tracer(void)
815{
816	int ret;
817
818	ret = register_tracer(&wakeup_tracer);
819	if (ret)
820		return ret;
821
822	ret = register_tracer(&wakeup_rt_tracer);
823	if (ret)
824		return ret;
825
826	ret = register_tracer(&wakeup_dl_tracer);
827	if (ret)
828		return ret;
829
830	return 0;
831}
832core_initcall(init_wakeup_tracer);