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1/*
2 * trace task wakeup timings
3 *
4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
6 *
7 * Based on code from the latency_tracer, that is:
8 *
9 * Copyright (C) 2004-2006 Ingo Molnar
10 * Copyright (C) 2004 Nadia Yvette Chambers
11 */
12#include <linux/module.h>
13#include <linux/kallsyms.h>
14#include <linux/uaccess.h>
15#include <linux/ftrace.h>
16#include <linux/sched/rt.h>
17#include <linux/sched/deadline.h>
18#include <trace/events/sched.h>
19#include "trace.h"
20
21static struct trace_array *wakeup_trace;
22static int __read_mostly tracer_enabled;
23
24static struct task_struct *wakeup_task;
25static int wakeup_cpu;
26static int wakeup_current_cpu;
27static unsigned wakeup_prio = -1;
28static int wakeup_rt;
29static int wakeup_dl;
30static int tracing_dl = 0;
31
32static arch_spinlock_t wakeup_lock =
33 (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
34
35static void wakeup_reset(struct trace_array *tr);
36static void __wakeup_reset(struct trace_array *tr);
37
38static int save_flags;
39
40#ifdef CONFIG_FUNCTION_GRAPH_TRACER
41static int wakeup_display_graph(struct trace_array *tr, int set);
42# define is_graph(tr) ((tr)->trace_flags & TRACE_ITER_DISPLAY_GRAPH)
43#else
44static inline int wakeup_display_graph(struct trace_array *tr, int set)
45{
46 return 0;
47}
48# define is_graph(tr) false
49#endif
50
51
52#ifdef CONFIG_FUNCTION_TRACER
53
54static int wakeup_graph_entry(struct ftrace_graph_ent *trace);
55static void wakeup_graph_return(struct ftrace_graph_ret *trace);
56
57static bool function_enabled;
58
59/*
60 * Prologue for the wakeup function tracers.
61 *
62 * Returns 1 if it is OK to continue, and preemption
63 * is disabled and data->disabled is incremented.
64 * 0 if the trace is to be ignored, and preemption
65 * is not disabled and data->disabled is
66 * kept the same.
67 *
68 * Note, this function is also used outside this ifdef but
69 * inside the #ifdef of the function graph tracer below.
70 * This is OK, since the function graph tracer is
71 * dependent on the function tracer.
72 */
73static int
74func_prolog_preempt_disable(struct trace_array *tr,
75 struct trace_array_cpu **data,
76 int *pc)
77{
78 long disabled;
79 int cpu;
80
81 if (likely(!wakeup_task))
82 return 0;
83
84 *pc = preempt_count();
85 preempt_disable_notrace();
86
87 cpu = raw_smp_processor_id();
88 if (cpu != wakeup_current_cpu)
89 goto out_enable;
90
91 *data = per_cpu_ptr(tr->trace_buffer.data, cpu);
92 disabled = atomic_inc_return(&(*data)->disabled);
93 if (unlikely(disabled != 1))
94 goto out;
95
96 return 1;
97
98out:
99 atomic_dec(&(*data)->disabled);
100
101out_enable:
102 preempt_enable_notrace();
103 return 0;
104}
105
106/*
107 * wakeup uses its own tracer function to keep the overhead down:
108 */
109static void
110wakeup_tracer_call(unsigned long ip, unsigned long parent_ip,
111 struct ftrace_ops *op, struct pt_regs *pt_regs)
112{
113 struct trace_array *tr = wakeup_trace;
114 struct trace_array_cpu *data;
115 unsigned long flags;
116 int pc;
117
118 if (!func_prolog_preempt_disable(tr, &data, &pc))
119 return;
120
121 local_irq_save(flags);
122 trace_function(tr, ip, parent_ip, flags, pc);
123 local_irq_restore(flags);
124
125 atomic_dec(&data->disabled);
126 preempt_enable_notrace();
127}
128
129static int register_wakeup_function(struct trace_array *tr, int graph, int set)
130{
131 int ret;
132
133 /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
134 if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION)))
135 return 0;
136
137 if (graph)
138 ret = register_ftrace_graph(&wakeup_graph_return,
139 &wakeup_graph_entry);
140 else
141 ret = register_ftrace_function(tr->ops);
142
143 if (!ret)
144 function_enabled = true;
145
146 return ret;
147}
148
149static void unregister_wakeup_function(struct trace_array *tr, int graph)
150{
151 if (!function_enabled)
152 return;
153
154 if (graph)
155 unregister_ftrace_graph();
156 else
157 unregister_ftrace_function(tr->ops);
158
159 function_enabled = false;
160}
161
162static int wakeup_function_set(struct trace_array *tr, u32 mask, int set)
163{
164 if (!(mask & TRACE_ITER_FUNCTION))
165 return 0;
166
167 if (set)
168 register_wakeup_function(tr, is_graph(tr), 1);
169 else
170 unregister_wakeup_function(tr, is_graph(tr));
171 return 1;
172}
173#else
174static int register_wakeup_function(struct trace_array *tr, int graph, int set)
175{
176 return 0;
177}
178static void unregister_wakeup_function(struct trace_array *tr, int graph) { }
179static int wakeup_function_set(struct trace_array *tr, u32 mask, int set)
180{
181 return 0;
182}
183#endif /* CONFIG_FUNCTION_TRACER */
184
185static int wakeup_flag_changed(struct trace_array *tr, u32 mask, int set)
186{
187 struct tracer *tracer = tr->current_trace;
188
189 if (wakeup_function_set(tr, mask, set))
190 return 0;
191
192#ifdef CONFIG_FUNCTION_GRAPH_TRACER
193 if (mask & TRACE_ITER_DISPLAY_GRAPH)
194 return wakeup_display_graph(tr, set);
195#endif
196
197 return trace_keep_overwrite(tracer, mask, set);
198}
199
200static int start_func_tracer(struct trace_array *tr, int graph)
201{
202 int ret;
203
204 ret = register_wakeup_function(tr, graph, 0);
205
206 if (!ret && tracing_is_enabled())
207 tracer_enabled = 1;
208 else
209 tracer_enabled = 0;
210
211 return ret;
212}
213
214static void stop_func_tracer(struct trace_array *tr, int graph)
215{
216 tracer_enabled = 0;
217
218 unregister_wakeup_function(tr, graph);
219}
220
221#ifdef CONFIG_FUNCTION_GRAPH_TRACER
222static int wakeup_display_graph(struct trace_array *tr, int set)
223{
224 if (!(is_graph(tr) ^ set))
225 return 0;
226
227 stop_func_tracer(tr, !set);
228
229 wakeup_reset(wakeup_trace);
230 tr->max_latency = 0;
231
232 return start_func_tracer(tr, set);
233}
234
235static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
236{
237 struct trace_array *tr = wakeup_trace;
238 struct trace_array_cpu *data;
239 unsigned long flags;
240 int pc, ret = 0;
241
242 if (!func_prolog_preempt_disable(tr, &data, &pc))
243 return 0;
244
245 local_save_flags(flags);
246 ret = __trace_graph_entry(tr, trace, flags, pc);
247 atomic_dec(&data->disabled);
248 preempt_enable_notrace();
249
250 return ret;
251}
252
253static void wakeup_graph_return(struct ftrace_graph_ret *trace)
254{
255 struct trace_array *tr = wakeup_trace;
256 struct trace_array_cpu *data;
257 unsigned long flags;
258 int pc;
259
260 if (!func_prolog_preempt_disable(tr, &data, &pc))
261 return;
262
263 local_save_flags(flags);
264 __trace_graph_return(tr, trace, flags, pc);
265 atomic_dec(&data->disabled);
266
267 preempt_enable_notrace();
268 return;
269}
270
271static void wakeup_trace_open(struct trace_iterator *iter)
272{
273 if (is_graph(iter->tr))
274 graph_trace_open(iter);
275}
276
277static void wakeup_trace_close(struct trace_iterator *iter)
278{
279 if (iter->private)
280 graph_trace_close(iter);
281}
282
283#define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_PROC | \
284 TRACE_GRAPH_PRINT_ABS_TIME | \
285 TRACE_GRAPH_PRINT_DURATION)
286
287static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
288{
289 /*
290 * In graph mode call the graph tracer output function,
291 * otherwise go with the TRACE_FN event handler
292 */
293 if (is_graph(iter->tr))
294 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
295
296 return TRACE_TYPE_UNHANDLED;
297}
298
299static void wakeup_print_header(struct seq_file *s)
300{
301 if (is_graph(wakeup_trace))
302 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
303 else
304 trace_default_header(s);
305}
306
307static void
308__trace_function(struct trace_array *tr,
309 unsigned long ip, unsigned long parent_ip,
310 unsigned long flags, int pc)
311{
312 if (is_graph(tr))
313 trace_graph_function(tr, ip, parent_ip, flags, pc);
314 else
315 trace_function(tr, ip, parent_ip, flags, pc);
316}
317#else
318#define __trace_function trace_function
319
320static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
321{
322 return TRACE_TYPE_UNHANDLED;
323}
324
325static void wakeup_trace_open(struct trace_iterator *iter) { }
326static void wakeup_trace_close(struct trace_iterator *iter) { }
327
328#ifdef CONFIG_FUNCTION_TRACER
329static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
330{
331 return -1;
332}
333static void wakeup_graph_return(struct ftrace_graph_ret *trace) { }
334static void wakeup_print_header(struct seq_file *s)
335{
336 trace_default_header(s);
337}
338#else
339static void wakeup_print_header(struct seq_file *s)
340{
341 trace_latency_header(s);
342}
343#endif /* CONFIG_FUNCTION_TRACER */
344#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
345
346/*
347 * Should this new latency be reported/recorded?
348 */
349static bool report_latency(struct trace_array *tr, cycle_t delta)
350{
351 if (tracing_thresh) {
352 if (delta < tracing_thresh)
353 return false;
354 } else {
355 if (delta <= tr->max_latency)
356 return false;
357 }
358 return true;
359}
360
361static void
362probe_wakeup_migrate_task(void *ignore, struct task_struct *task, int cpu)
363{
364 if (task != wakeup_task)
365 return;
366
367 wakeup_current_cpu = cpu;
368}
369
370static void
371tracing_sched_switch_trace(struct trace_array *tr,
372 struct task_struct *prev,
373 struct task_struct *next,
374 unsigned long flags, int pc)
375{
376 struct trace_event_call *call = &event_context_switch;
377 struct ring_buffer *buffer = tr->trace_buffer.buffer;
378 struct ring_buffer_event *event;
379 struct ctx_switch_entry *entry;
380
381 event = trace_buffer_lock_reserve(buffer, TRACE_CTX,
382 sizeof(*entry), flags, pc);
383 if (!event)
384 return;
385 entry = ring_buffer_event_data(event);
386 entry->prev_pid = prev->pid;
387 entry->prev_prio = prev->prio;
388 entry->prev_state = prev->state;
389 entry->next_pid = next->pid;
390 entry->next_prio = next->prio;
391 entry->next_state = next->state;
392 entry->next_cpu = task_cpu(next);
393
394 if (!call_filter_check_discard(call, entry, buffer, event))
395 trace_buffer_unlock_commit(tr, buffer, event, flags, pc);
396}
397
398static void
399tracing_sched_wakeup_trace(struct trace_array *tr,
400 struct task_struct *wakee,
401 struct task_struct *curr,
402 unsigned long flags, int pc)
403{
404 struct trace_event_call *call = &event_wakeup;
405 struct ring_buffer_event *event;
406 struct ctx_switch_entry *entry;
407 struct ring_buffer *buffer = tr->trace_buffer.buffer;
408
409 event = trace_buffer_lock_reserve(buffer, TRACE_WAKE,
410 sizeof(*entry), flags, pc);
411 if (!event)
412 return;
413 entry = ring_buffer_event_data(event);
414 entry->prev_pid = curr->pid;
415 entry->prev_prio = curr->prio;
416 entry->prev_state = curr->state;
417 entry->next_pid = wakee->pid;
418 entry->next_prio = wakee->prio;
419 entry->next_state = wakee->state;
420 entry->next_cpu = task_cpu(wakee);
421
422 if (!call_filter_check_discard(call, entry, buffer, event))
423 trace_buffer_unlock_commit(tr, buffer, event, flags, pc);
424}
425
426static void notrace
427probe_wakeup_sched_switch(void *ignore, bool preempt,
428 struct task_struct *prev, struct task_struct *next)
429{
430 struct trace_array_cpu *data;
431 cycle_t T0, T1, delta;
432 unsigned long flags;
433 long disabled;
434 int cpu;
435 int pc;
436
437 tracing_record_cmdline(prev);
438
439 if (unlikely(!tracer_enabled))
440 return;
441
442 /*
443 * When we start a new trace, we set wakeup_task to NULL
444 * and then set tracer_enabled = 1. We want to make sure
445 * that another CPU does not see the tracer_enabled = 1
446 * and the wakeup_task with an older task, that might
447 * actually be the same as next.
448 */
449 smp_rmb();
450
451 if (next != wakeup_task)
452 return;
453
454 pc = preempt_count();
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->trace_buffer.data, cpu)->disabled);
459 if (likely(disabled != 1))
460 goto out;
461
462 local_irq_save(flags);
463 arch_spin_lock(&wakeup_lock);
464
465 /* We could race with grabbing wakeup_lock */
466 if (unlikely(!tracer_enabled || next != wakeup_task))
467 goto out_unlock;
468
469 /* The task we are waiting for is waking up */
470 data = per_cpu_ptr(wakeup_trace->trace_buffer.data, wakeup_cpu);
471
472 __trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, flags, pc);
473 tracing_sched_switch_trace(wakeup_trace, prev, next, flags, pc);
474
475 T0 = data->preempt_timestamp;
476 T1 = ftrace_now(cpu);
477 delta = T1-T0;
478
479 if (!report_latency(wakeup_trace, delta))
480 goto out_unlock;
481
482 if (likely(!is_tracing_stopped())) {
483 wakeup_trace->max_latency = delta;
484 update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu);
485 }
486
487out_unlock:
488 __wakeup_reset(wakeup_trace);
489 arch_spin_unlock(&wakeup_lock);
490 local_irq_restore(flags);
491out:
492 atomic_dec(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
493}
494
495static void __wakeup_reset(struct trace_array *tr)
496{
497 wakeup_cpu = -1;
498 wakeup_prio = -1;
499 tracing_dl = 0;
500
501 if (wakeup_task)
502 put_task_struct(wakeup_task);
503
504 wakeup_task = NULL;
505}
506
507static void wakeup_reset(struct trace_array *tr)
508{
509 unsigned long flags;
510
511 tracing_reset_online_cpus(&tr->trace_buffer);
512
513 local_irq_save(flags);
514 arch_spin_lock(&wakeup_lock);
515 __wakeup_reset(tr);
516 arch_spin_unlock(&wakeup_lock);
517 local_irq_restore(flags);
518}
519
520static void
521probe_wakeup(void *ignore, struct task_struct *p)
522{
523 struct trace_array_cpu *data;
524 int cpu = smp_processor_id();
525 unsigned long flags;
526 long disabled;
527 int pc;
528
529 if (likely(!tracer_enabled))
530 return;
531
532 tracing_record_cmdline(p);
533 tracing_record_cmdline(current);
534
535 /*
536 * Semantic is like this:
537 * - wakeup tracer handles all tasks in the system, independently
538 * from their scheduling class;
539 * - wakeup_rt tracer handles tasks belonging to sched_dl and
540 * sched_rt class;
541 * - wakeup_dl handles tasks belonging to sched_dl class only.
542 */
543 if (tracing_dl || (wakeup_dl && !dl_task(p)) ||
544 (wakeup_rt && !dl_task(p) && !rt_task(p)) ||
545 (!dl_task(p) && (p->prio >= wakeup_prio || p->prio >= current->prio)))
546 return;
547
548 pc = preempt_count();
549 disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
550 if (unlikely(disabled != 1))
551 goto out;
552
553 /* interrupts should be off from try_to_wake_up */
554 arch_spin_lock(&wakeup_lock);
555
556 /* check for races. */
557 if (!tracer_enabled || tracing_dl ||
558 (!dl_task(p) && p->prio >= wakeup_prio))
559 goto out_locked;
560
561 /* reset the trace */
562 __wakeup_reset(wakeup_trace);
563
564 wakeup_cpu = task_cpu(p);
565 wakeup_current_cpu = wakeup_cpu;
566 wakeup_prio = p->prio;
567
568 /*
569 * Once you start tracing a -deadline task, don't bother tracing
570 * another task until the first one wakes up.
571 */
572 if (dl_task(p))
573 tracing_dl = 1;
574 else
575 tracing_dl = 0;
576
577 wakeup_task = p;
578 get_task_struct(wakeup_task);
579
580 local_save_flags(flags);
581
582 data = per_cpu_ptr(wakeup_trace->trace_buffer.data, wakeup_cpu);
583 data->preempt_timestamp = ftrace_now(cpu);
584 tracing_sched_wakeup_trace(wakeup_trace, p, current, flags, pc);
585
586 /*
587 * We must be careful in using CALLER_ADDR2. But since wake_up
588 * is not called by an assembly function (where as schedule is)
589 * it should be safe to use it here.
590 */
591 __trace_function(wakeup_trace, CALLER_ADDR1, CALLER_ADDR2, flags, pc);
592
593out_locked:
594 arch_spin_unlock(&wakeup_lock);
595out:
596 atomic_dec(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
597}
598
599static void start_wakeup_tracer(struct trace_array *tr)
600{
601 int ret;
602
603 ret = register_trace_sched_wakeup(probe_wakeup, NULL);
604 if (ret) {
605 pr_info("wakeup trace: Couldn't activate tracepoint"
606 " probe to kernel_sched_wakeup\n");
607 return;
608 }
609
610 ret = register_trace_sched_wakeup_new(probe_wakeup, NULL);
611 if (ret) {
612 pr_info("wakeup trace: Couldn't activate tracepoint"
613 " probe to kernel_sched_wakeup_new\n");
614 goto fail_deprobe;
615 }
616
617 ret = register_trace_sched_switch(probe_wakeup_sched_switch, NULL);
618 if (ret) {
619 pr_info("sched trace: Couldn't activate tracepoint"
620 " probe to kernel_sched_switch\n");
621 goto fail_deprobe_wake_new;
622 }
623
624 ret = register_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
625 if (ret) {
626 pr_info("wakeup trace: Couldn't activate tracepoint"
627 " probe to kernel_sched_migrate_task\n");
628 return;
629 }
630
631 wakeup_reset(tr);
632
633 /*
634 * Don't let the tracer_enabled = 1 show up before
635 * the wakeup_task is reset. This may be overkill since
636 * wakeup_reset does a spin_unlock after setting the
637 * wakeup_task to NULL, but I want to be safe.
638 * This is a slow path anyway.
639 */
640 smp_wmb();
641
642 if (start_func_tracer(tr, is_graph(tr)))
643 printk(KERN_ERR "failed to start wakeup tracer\n");
644
645 return;
646fail_deprobe_wake_new:
647 unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
648fail_deprobe:
649 unregister_trace_sched_wakeup(probe_wakeup, NULL);
650}
651
652static void stop_wakeup_tracer(struct trace_array *tr)
653{
654 tracer_enabled = 0;
655 stop_func_tracer(tr, is_graph(tr));
656 unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
657 unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
658 unregister_trace_sched_wakeup(probe_wakeup, NULL);
659 unregister_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
660}
661
662static bool wakeup_busy;
663
664static int __wakeup_tracer_init(struct trace_array *tr)
665{
666 save_flags = tr->trace_flags;
667
668 /* non overwrite screws up the latency tracers */
669 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
670 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
671
672 tr->max_latency = 0;
673 wakeup_trace = tr;
674 ftrace_init_array_ops(tr, wakeup_tracer_call);
675 start_wakeup_tracer(tr);
676
677 wakeup_busy = true;
678 return 0;
679}
680
681static int wakeup_tracer_init(struct trace_array *tr)
682{
683 if (wakeup_busy)
684 return -EBUSY;
685
686 wakeup_dl = 0;
687 wakeup_rt = 0;
688 return __wakeup_tracer_init(tr);
689}
690
691static int wakeup_rt_tracer_init(struct trace_array *tr)
692{
693 if (wakeup_busy)
694 return -EBUSY;
695
696 wakeup_dl = 0;
697 wakeup_rt = 1;
698 return __wakeup_tracer_init(tr);
699}
700
701static int wakeup_dl_tracer_init(struct trace_array *tr)
702{
703 if (wakeup_busy)
704 return -EBUSY;
705
706 wakeup_dl = 1;
707 wakeup_rt = 0;
708 return __wakeup_tracer_init(tr);
709}
710
711static void wakeup_tracer_reset(struct trace_array *tr)
712{
713 int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
714 int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
715
716 stop_wakeup_tracer(tr);
717 /* make sure we put back any tasks we are tracing */
718 wakeup_reset(tr);
719
720 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
721 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
722 ftrace_reset_array_ops(tr);
723 wakeup_busy = false;
724}
725
726static void wakeup_tracer_start(struct trace_array *tr)
727{
728 wakeup_reset(tr);
729 tracer_enabled = 1;
730}
731
732static void wakeup_tracer_stop(struct trace_array *tr)
733{
734 tracer_enabled = 0;
735}
736
737static struct tracer wakeup_tracer __read_mostly =
738{
739 .name = "wakeup",
740 .init = wakeup_tracer_init,
741 .reset = wakeup_tracer_reset,
742 .start = wakeup_tracer_start,
743 .stop = wakeup_tracer_stop,
744 .print_max = true,
745 .print_header = wakeup_print_header,
746 .print_line = wakeup_print_line,
747 .flag_changed = wakeup_flag_changed,
748#ifdef CONFIG_FTRACE_SELFTEST
749 .selftest = trace_selftest_startup_wakeup,
750#endif
751 .open = wakeup_trace_open,
752 .close = wakeup_trace_close,
753 .allow_instances = true,
754 .use_max_tr = true,
755};
756
757static struct tracer wakeup_rt_tracer __read_mostly =
758{
759 .name = "wakeup_rt",
760 .init = wakeup_rt_tracer_init,
761 .reset = wakeup_tracer_reset,
762 .start = wakeup_tracer_start,
763 .stop = wakeup_tracer_stop,
764 .print_max = true,
765 .print_header = wakeup_print_header,
766 .print_line = wakeup_print_line,
767 .flag_changed = wakeup_flag_changed,
768#ifdef CONFIG_FTRACE_SELFTEST
769 .selftest = trace_selftest_startup_wakeup,
770#endif
771 .open = wakeup_trace_open,
772 .close = wakeup_trace_close,
773 .allow_instances = true,
774 .use_max_tr = true,
775};
776
777static struct tracer wakeup_dl_tracer __read_mostly =
778{
779 .name = "wakeup_dl",
780 .init = wakeup_dl_tracer_init,
781 .reset = wakeup_tracer_reset,
782 .start = wakeup_tracer_start,
783 .stop = wakeup_tracer_stop,
784 .print_max = true,
785 .print_header = wakeup_print_header,
786 .print_line = wakeup_print_line,
787 .flag_changed = wakeup_flag_changed,
788#ifdef CONFIG_FTRACE_SELFTEST
789 .selftest = trace_selftest_startup_wakeup,
790#endif
791 .open = wakeup_trace_open,
792 .close = wakeup_trace_close,
793 .use_max_tr = true,
794};
795
796__init static int init_wakeup_tracer(void)
797{
798 int ret;
799
800 ret = register_tracer(&wakeup_tracer);
801 if (ret)
802 return ret;
803
804 ret = register_tracer(&wakeup_rt_tracer);
805 if (ret)
806 return ret;
807
808 ret = register_tracer(&wakeup_dl_tracer);
809 if (ret)
810 return ret;
811
812 return 0;
813}
814core_initcall(init_wakeup_tracer);
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 int wakeup_rt;
30static int wakeup_dl;
31static int tracing_dl = 0;
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);
38
39static int save_flags;
40
41#ifdef CONFIG_FUNCTION_GRAPH_TRACER
42static int wakeup_display_graph(struct trace_array *tr, int set);
43# define is_graph(tr) ((tr)->trace_flags & TRACE_ITER_DISPLAY_GRAPH)
44#else
45static inline int wakeup_display_graph(struct trace_array *tr, int set)
46{
47 return 0;
48}
49# define is_graph(tr) false
50#endif
51
52
53#ifdef CONFIG_FUNCTION_TRACER
54
55static int wakeup_graph_entry(struct ftrace_graph_ent *trace);
56static void wakeup_graph_return(struct ftrace_graph_ret *trace);
57
58static bool function_enabled;
59
60/*
61 * Prologue for the wakeup function tracers.
62 *
63 * Returns 1 if it is OK to continue, and preemption
64 * is disabled and data->disabled is incremented.
65 * 0 if the trace is to be ignored, and preemption
66 * is not disabled and data->disabled is
67 * kept the same.
68 *
69 * Note, this function is also used outside this ifdef but
70 * inside the #ifdef of the function graph tracer below.
71 * This is OK, since the function graph tracer is
72 * dependent on the function tracer.
73 */
74static int
75func_prolog_preempt_disable(struct trace_array *tr,
76 struct trace_array_cpu **data,
77 int *pc)
78{
79 long disabled;
80 int cpu;
81
82 if (likely(!wakeup_task))
83 return 0;
84
85 *pc = preempt_count();
86 preempt_disable_notrace();
87
88 cpu = raw_smp_processor_id();
89 if (cpu != wakeup_current_cpu)
90 goto out_enable;
91
92 *data = per_cpu_ptr(tr->trace_buffer.data, cpu);
93 disabled = atomic_inc_return(&(*data)->disabled);
94 if (unlikely(disabled != 1))
95 goto out;
96
97 return 1;
98
99out:
100 atomic_dec(&(*data)->disabled);
101
102out_enable:
103 preempt_enable_notrace();
104 return 0;
105}
106
107/*
108 * wakeup uses its own tracer function to keep the overhead down:
109 */
110static void
111wakeup_tracer_call(unsigned long ip, unsigned long parent_ip,
112 struct ftrace_ops *op, struct pt_regs *pt_regs)
113{
114 struct trace_array *tr = wakeup_trace;
115 struct trace_array_cpu *data;
116 unsigned long flags;
117 int pc;
118
119 if (!func_prolog_preempt_disable(tr, &data, &pc))
120 return;
121
122 local_irq_save(flags);
123 trace_function(tr, ip, parent_ip, flags, pc);
124 local_irq_restore(flags);
125
126 atomic_dec(&data->disabled);
127 preempt_enable_notrace();
128}
129
130static int register_wakeup_function(struct trace_array *tr, int graph, int set)
131{
132 int ret;
133
134 /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
135 if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION)))
136 return 0;
137
138 if (graph)
139 ret = register_ftrace_graph(&wakeup_graph_return,
140 &wakeup_graph_entry);
141 else
142 ret = register_ftrace_function(tr->ops);
143
144 if (!ret)
145 function_enabled = true;
146
147 return ret;
148}
149
150static void unregister_wakeup_function(struct trace_array *tr, int graph)
151{
152 if (!function_enabled)
153 return;
154
155 if (graph)
156 unregister_ftrace_graph();
157 else
158 unregister_ftrace_function(tr->ops);
159
160 function_enabled = false;
161}
162
163static int wakeup_function_set(struct trace_array *tr, u32 mask, int set)
164{
165 if (!(mask & TRACE_ITER_FUNCTION))
166 return 0;
167
168 if (set)
169 register_wakeup_function(tr, is_graph(tr), 1);
170 else
171 unregister_wakeup_function(tr, is_graph(tr));
172 return 1;
173}
174#else
175static int register_wakeup_function(struct trace_array *tr, int graph, int set)
176{
177 return 0;
178}
179static void unregister_wakeup_function(struct trace_array *tr, int graph) { }
180static int wakeup_function_set(struct trace_array *tr, u32 mask, int set)
181{
182 return 0;
183}
184#endif /* CONFIG_FUNCTION_TRACER */
185
186static int wakeup_flag_changed(struct trace_array *tr, u32 mask, int set)
187{
188 struct tracer *tracer = tr->current_trace;
189
190 if (wakeup_function_set(tr, mask, set))
191 return 0;
192
193#ifdef CONFIG_FUNCTION_GRAPH_TRACER
194 if (mask & TRACE_ITER_DISPLAY_GRAPH)
195 return wakeup_display_graph(tr, set);
196#endif
197
198 return trace_keep_overwrite(tracer, mask, set);
199}
200
201static int start_func_tracer(struct trace_array *tr, int graph)
202{
203 int ret;
204
205 ret = register_wakeup_function(tr, graph, 0);
206
207 if (!ret && tracing_is_enabled())
208 tracer_enabled = 1;
209 else
210 tracer_enabled = 0;
211
212 return ret;
213}
214
215static void stop_func_tracer(struct trace_array *tr, int graph)
216{
217 tracer_enabled = 0;
218
219 unregister_wakeup_function(tr, graph);
220}
221
222#ifdef CONFIG_FUNCTION_GRAPH_TRACER
223static int wakeup_display_graph(struct trace_array *tr, int set)
224{
225 if (!(is_graph(tr) ^ set))
226 return 0;
227
228 stop_func_tracer(tr, !set);
229
230 wakeup_reset(wakeup_trace);
231 tr->max_latency = 0;
232
233 return start_func_tracer(tr, set);
234}
235
236static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
237{
238 struct trace_array *tr = wakeup_trace;
239 struct trace_array_cpu *data;
240 unsigned long flags;
241 int pc, ret = 0;
242
243 if (ftrace_graph_ignore_func(trace))
244 return 0;
245 /*
246 * Do not trace a function if it's filtered by set_graph_notrace.
247 * Make the index of ret stack negative to indicate that it should
248 * ignore further functions. But it needs its own ret stack entry
249 * to recover the original index in order to continue tracing after
250 * returning from the function.
251 */
252 if (ftrace_graph_notrace_addr(trace->func))
253 return 1;
254
255 if (!func_prolog_preempt_disable(tr, &data, &pc))
256 return 0;
257
258 local_save_flags(flags);
259 ret = __trace_graph_entry(tr, trace, flags, pc);
260 atomic_dec(&data->disabled);
261 preempt_enable_notrace();
262
263 return ret;
264}
265
266static void wakeup_graph_return(struct ftrace_graph_ret *trace)
267{
268 struct trace_array *tr = wakeup_trace;
269 struct trace_array_cpu *data;
270 unsigned long flags;
271 int pc;
272
273 if (!func_prolog_preempt_disable(tr, &data, &pc))
274 return;
275
276 local_save_flags(flags);
277 __trace_graph_return(tr, trace, flags, pc);
278 atomic_dec(&data->disabled);
279
280 preempt_enable_notrace();
281 return;
282}
283
284static void wakeup_trace_open(struct trace_iterator *iter)
285{
286 if (is_graph(iter->tr))
287 graph_trace_open(iter);
288}
289
290static void wakeup_trace_close(struct trace_iterator *iter)
291{
292 if (iter->private)
293 graph_trace_close(iter);
294}
295
296#define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_PROC | \
297 TRACE_GRAPH_PRINT_ABS_TIME | \
298 TRACE_GRAPH_PRINT_DURATION)
299
300static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
301{
302 /*
303 * In graph mode call the graph tracer output function,
304 * otherwise go with the TRACE_FN event handler
305 */
306 if (is_graph(iter->tr))
307 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
308
309 return TRACE_TYPE_UNHANDLED;
310}
311
312static void wakeup_print_header(struct seq_file *s)
313{
314 if (is_graph(wakeup_trace))
315 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
316 else
317 trace_default_header(s);
318}
319
320static void
321__trace_function(struct trace_array *tr,
322 unsigned long ip, unsigned long parent_ip,
323 unsigned long flags, int pc)
324{
325 if (is_graph(tr))
326 trace_graph_function(tr, ip, parent_ip, flags, pc);
327 else
328 trace_function(tr, ip, parent_ip, flags, pc);
329}
330#else
331#define __trace_function trace_function
332
333static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
334{
335 return TRACE_TYPE_UNHANDLED;
336}
337
338static void wakeup_trace_open(struct trace_iterator *iter) { }
339static void wakeup_trace_close(struct trace_iterator *iter) { }
340
341#ifdef CONFIG_FUNCTION_TRACER
342static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
343{
344 return -1;
345}
346static void wakeup_graph_return(struct ftrace_graph_ret *trace) { }
347static void wakeup_print_header(struct seq_file *s)
348{
349 trace_default_header(s);
350}
351#else
352static void wakeup_print_header(struct seq_file *s)
353{
354 trace_latency_header(s);
355}
356#endif /* CONFIG_FUNCTION_TRACER */
357#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
358
359/*
360 * Should this new latency be reported/recorded?
361 */
362static bool report_latency(struct trace_array *tr, u64 delta)
363{
364 if (tracing_thresh) {
365 if (delta < tracing_thresh)
366 return false;
367 } else {
368 if (delta <= tr->max_latency)
369 return false;
370 }
371 return true;
372}
373
374static void
375probe_wakeup_migrate_task(void *ignore, struct task_struct *task, int cpu)
376{
377 if (task != wakeup_task)
378 return;
379
380 wakeup_current_cpu = cpu;
381}
382
383static void
384tracing_sched_switch_trace(struct trace_array *tr,
385 struct task_struct *prev,
386 struct task_struct *next,
387 unsigned long flags, int pc)
388{
389 struct trace_event_call *call = &event_context_switch;
390 struct ring_buffer *buffer = tr->trace_buffer.buffer;
391 struct ring_buffer_event *event;
392 struct ctx_switch_entry *entry;
393
394 event = trace_buffer_lock_reserve(buffer, TRACE_CTX,
395 sizeof(*entry), flags, pc);
396 if (!event)
397 return;
398 entry = ring_buffer_event_data(event);
399 entry->prev_pid = prev->pid;
400 entry->prev_prio = prev->prio;
401 entry->prev_state = task_state_index(prev);
402 entry->next_pid = next->pid;
403 entry->next_prio = next->prio;
404 entry->next_state = task_state_index(next);
405 entry->next_cpu = task_cpu(next);
406
407 if (!call_filter_check_discard(call, entry, buffer, event))
408 trace_buffer_unlock_commit(tr, buffer, event, flags, pc);
409}
410
411static void
412tracing_sched_wakeup_trace(struct trace_array *tr,
413 struct task_struct *wakee,
414 struct task_struct *curr,
415 unsigned long flags, int pc)
416{
417 struct trace_event_call *call = &event_wakeup;
418 struct ring_buffer_event *event;
419 struct ctx_switch_entry *entry;
420 struct ring_buffer *buffer = tr->trace_buffer.buffer;
421
422 event = trace_buffer_lock_reserve(buffer, TRACE_WAKE,
423 sizeof(*entry), flags, pc);
424 if (!event)
425 return;
426 entry = ring_buffer_event_data(event);
427 entry->prev_pid = curr->pid;
428 entry->prev_prio = curr->prio;
429 entry->prev_state = task_state_index(curr);
430 entry->next_pid = wakee->pid;
431 entry->next_prio = wakee->prio;
432 entry->next_state = task_state_index(wakee);
433 entry->next_cpu = task_cpu(wakee);
434
435 if (!call_filter_check_discard(call, entry, buffer, event))
436 trace_buffer_unlock_commit(tr, buffer, event, flags, pc);
437}
438
439static void notrace
440probe_wakeup_sched_switch(void *ignore, bool preempt,
441 struct task_struct *prev, struct task_struct *next)
442{
443 struct trace_array_cpu *data;
444 u64 T0, T1, delta;
445 unsigned long flags;
446 long disabled;
447 int cpu;
448 int pc;
449
450 tracing_record_cmdline(prev);
451
452 if (unlikely(!tracer_enabled))
453 return;
454
455 /*
456 * When we start a new trace, we set wakeup_task to NULL
457 * and then set tracer_enabled = 1. We want to make sure
458 * that another CPU does not see the tracer_enabled = 1
459 * and the wakeup_task with an older task, that might
460 * actually be the same as next.
461 */
462 smp_rmb();
463
464 if (next != wakeup_task)
465 return;
466
467 pc = preempt_count();
468
469 /* disable local data, not wakeup_cpu data */
470 cpu = raw_smp_processor_id();
471 disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
472 if (likely(disabled != 1))
473 goto out;
474
475 local_irq_save(flags);
476 arch_spin_lock(&wakeup_lock);
477
478 /* We could race with grabbing wakeup_lock */
479 if (unlikely(!tracer_enabled || next != wakeup_task))
480 goto out_unlock;
481
482 /* The task we are waiting for is waking up */
483 data = per_cpu_ptr(wakeup_trace->trace_buffer.data, wakeup_cpu);
484
485 __trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, flags, pc);
486 tracing_sched_switch_trace(wakeup_trace, prev, next, flags, pc);
487
488 T0 = data->preempt_timestamp;
489 T1 = ftrace_now(cpu);
490 delta = T1-T0;
491
492 if (!report_latency(wakeup_trace, delta))
493 goto out_unlock;
494
495 if (likely(!is_tracing_stopped())) {
496 wakeup_trace->max_latency = delta;
497 update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu);
498 }
499
500out_unlock:
501 __wakeup_reset(wakeup_trace);
502 arch_spin_unlock(&wakeup_lock);
503 local_irq_restore(flags);
504out:
505 atomic_dec(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
506}
507
508static void __wakeup_reset(struct trace_array *tr)
509{
510 wakeup_cpu = -1;
511 wakeup_prio = -1;
512 tracing_dl = 0;
513
514 if (wakeup_task)
515 put_task_struct(wakeup_task);
516
517 wakeup_task = NULL;
518}
519
520static void wakeup_reset(struct trace_array *tr)
521{
522 unsigned long flags;
523
524 tracing_reset_online_cpus(&tr->trace_buffer);
525
526 local_irq_save(flags);
527 arch_spin_lock(&wakeup_lock);
528 __wakeup_reset(tr);
529 arch_spin_unlock(&wakeup_lock);
530 local_irq_restore(flags);
531}
532
533static void
534probe_wakeup(void *ignore, struct task_struct *p)
535{
536 struct trace_array_cpu *data;
537 int cpu = smp_processor_id();
538 unsigned long flags;
539 long disabled;
540 int pc;
541
542 if (likely(!tracer_enabled))
543 return;
544
545 tracing_record_cmdline(p);
546 tracing_record_cmdline(current);
547
548 /*
549 * Semantic is like this:
550 * - wakeup tracer handles all tasks in the system, independently
551 * from their scheduling class;
552 * - wakeup_rt tracer handles tasks belonging to sched_dl and
553 * sched_rt class;
554 * - wakeup_dl handles tasks belonging to sched_dl class only.
555 */
556 if (tracing_dl || (wakeup_dl && !dl_task(p)) ||
557 (wakeup_rt && !dl_task(p) && !rt_task(p)) ||
558 (!dl_task(p) && (p->prio >= wakeup_prio || p->prio >= current->prio)))
559 return;
560
561 pc = preempt_count();
562 disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
563 if (unlikely(disabled != 1))
564 goto out;
565
566 /* interrupts should be off from try_to_wake_up */
567 arch_spin_lock(&wakeup_lock);
568
569 /* check for races. */
570 if (!tracer_enabled || tracing_dl ||
571 (!dl_task(p) && p->prio >= wakeup_prio))
572 goto out_locked;
573
574 /* reset the trace */
575 __wakeup_reset(wakeup_trace);
576
577 wakeup_cpu = task_cpu(p);
578 wakeup_current_cpu = wakeup_cpu;
579 wakeup_prio = p->prio;
580
581 /*
582 * Once you start tracing a -deadline task, don't bother tracing
583 * another task until the first one wakes up.
584 */
585 if (dl_task(p))
586 tracing_dl = 1;
587 else
588 tracing_dl = 0;
589
590 wakeup_task = p;
591 get_task_struct(wakeup_task);
592
593 local_save_flags(flags);
594
595 data = per_cpu_ptr(wakeup_trace->trace_buffer.data, wakeup_cpu);
596 data->preempt_timestamp = ftrace_now(cpu);
597 tracing_sched_wakeup_trace(wakeup_trace, p, current, flags, pc);
598
599 /*
600 * We must be careful in using CALLER_ADDR2. But since wake_up
601 * is not called by an assembly function (where as schedule is)
602 * it should be safe to use it here.
603 */
604 __trace_function(wakeup_trace, CALLER_ADDR1, CALLER_ADDR2, flags, pc);
605
606out_locked:
607 arch_spin_unlock(&wakeup_lock);
608out:
609 atomic_dec(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
610}
611
612static void start_wakeup_tracer(struct trace_array *tr)
613{
614 int ret;
615
616 ret = register_trace_sched_wakeup(probe_wakeup, NULL);
617 if (ret) {
618 pr_info("wakeup trace: Couldn't activate tracepoint"
619 " probe to kernel_sched_wakeup\n");
620 return;
621 }
622
623 ret = register_trace_sched_wakeup_new(probe_wakeup, NULL);
624 if (ret) {
625 pr_info("wakeup trace: Couldn't activate tracepoint"
626 " probe to kernel_sched_wakeup_new\n");
627 goto fail_deprobe;
628 }
629
630 ret = register_trace_sched_switch(probe_wakeup_sched_switch, NULL);
631 if (ret) {
632 pr_info("sched trace: Couldn't activate tracepoint"
633 " probe to kernel_sched_switch\n");
634 goto fail_deprobe_wake_new;
635 }
636
637 ret = register_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
638 if (ret) {
639 pr_info("wakeup trace: Couldn't activate tracepoint"
640 " probe to kernel_sched_migrate_task\n");
641 return;
642 }
643
644 wakeup_reset(tr);
645
646 /*
647 * Don't let the tracer_enabled = 1 show up before
648 * the wakeup_task is reset. This may be overkill since
649 * wakeup_reset does a spin_unlock after setting the
650 * wakeup_task to NULL, but I want to be safe.
651 * This is a slow path anyway.
652 */
653 smp_wmb();
654
655 if (start_func_tracer(tr, is_graph(tr)))
656 printk(KERN_ERR "failed to start wakeup tracer\n");
657
658 return;
659fail_deprobe_wake_new:
660 unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
661fail_deprobe:
662 unregister_trace_sched_wakeup(probe_wakeup, NULL);
663}
664
665static void stop_wakeup_tracer(struct trace_array *tr)
666{
667 tracer_enabled = 0;
668 stop_func_tracer(tr, is_graph(tr));
669 unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
670 unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
671 unregister_trace_sched_wakeup(probe_wakeup, NULL);
672 unregister_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
673}
674
675static bool wakeup_busy;
676
677static int __wakeup_tracer_init(struct trace_array *tr)
678{
679 save_flags = tr->trace_flags;
680
681 /* non overwrite screws up the latency tracers */
682 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
683 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
684
685 tr->max_latency = 0;
686 wakeup_trace = tr;
687 ftrace_init_array_ops(tr, wakeup_tracer_call);
688 start_wakeup_tracer(tr);
689
690 wakeup_busy = true;
691 return 0;
692}
693
694static int wakeup_tracer_init(struct trace_array *tr)
695{
696 if (wakeup_busy)
697 return -EBUSY;
698
699 wakeup_dl = 0;
700 wakeup_rt = 0;
701 return __wakeup_tracer_init(tr);
702}
703
704static int wakeup_rt_tracer_init(struct trace_array *tr)
705{
706 if (wakeup_busy)
707 return -EBUSY;
708
709 wakeup_dl = 0;
710 wakeup_rt = 1;
711 return __wakeup_tracer_init(tr);
712}
713
714static int wakeup_dl_tracer_init(struct trace_array *tr)
715{
716 if (wakeup_busy)
717 return -EBUSY;
718
719 wakeup_dl = 1;
720 wakeup_rt = 0;
721 return __wakeup_tracer_init(tr);
722}
723
724static void wakeup_tracer_reset(struct trace_array *tr)
725{
726 int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
727 int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
728
729 stop_wakeup_tracer(tr);
730 /* make sure we put back any tasks we are tracing */
731 wakeup_reset(tr);
732
733 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
734 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
735 ftrace_reset_array_ops(tr);
736 wakeup_busy = false;
737}
738
739static void wakeup_tracer_start(struct trace_array *tr)
740{
741 wakeup_reset(tr);
742 tracer_enabled = 1;
743}
744
745static void wakeup_tracer_stop(struct trace_array *tr)
746{
747 tracer_enabled = 0;
748}
749
750static struct tracer wakeup_tracer __read_mostly =
751{
752 .name = "wakeup",
753 .init = wakeup_tracer_init,
754 .reset = wakeup_tracer_reset,
755 .start = wakeup_tracer_start,
756 .stop = wakeup_tracer_stop,
757 .print_max = true,
758 .print_header = wakeup_print_header,
759 .print_line = wakeup_print_line,
760 .flag_changed = wakeup_flag_changed,
761#ifdef CONFIG_FTRACE_SELFTEST
762 .selftest = trace_selftest_startup_wakeup,
763#endif
764 .open = wakeup_trace_open,
765 .close = wakeup_trace_close,
766 .allow_instances = true,
767 .use_max_tr = true,
768};
769
770static struct tracer wakeup_rt_tracer __read_mostly =
771{
772 .name = "wakeup_rt",
773 .init = wakeup_rt_tracer_init,
774 .reset = wakeup_tracer_reset,
775 .start = wakeup_tracer_start,
776 .stop = wakeup_tracer_stop,
777 .print_max = true,
778 .print_header = wakeup_print_header,
779 .print_line = wakeup_print_line,
780 .flag_changed = wakeup_flag_changed,
781#ifdef CONFIG_FTRACE_SELFTEST
782 .selftest = trace_selftest_startup_wakeup,
783#endif
784 .open = wakeup_trace_open,
785 .close = wakeup_trace_close,
786 .allow_instances = true,
787 .use_max_tr = true,
788};
789
790static struct tracer wakeup_dl_tracer __read_mostly =
791{
792 .name = "wakeup_dl",
793 .init = wakeup_dl_tracer_init,
794 .reset = wakeup_tracer_reset,
795 .start = wakeup_tracer_start,
796 .stop = wakeup_tracer_stop,
797 .print_max = true,
798 .print_header = wakeup_print_header,
799 .print_line = wakeup_print_line,
800 .flag_changed = wakeup_flag_changed,
801#ifdef CONFIG_FTRACE_SELFTEST
802 .selftest = trace_selftest_startup_wakeup,
803#endif
804 .open = wakeup_trace_open,
805 .close = wakeup_trace_close,
806 .allow_instances = true,
807 .use_max_tr = true,
808};
809
810__init static int init_wakeup_tracer(void)
811{
812 int ret;
813
814 ret = register_tracer(&wakeup_tracer);
815 if (ret)
816 return ret;
817
818 ret = register_tracer(&wakeup_rt_tracer);
819 if (ret)
820 return ret;
821
822 ret = register_tracer(&wakeup_dl_tracer);
823 if (ret)
824 return ret;
825
826 return 0;
827}
828core_initcall(init_wakeup_tracer);