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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 else
172 iter->private = NULL;
173}
174
175static 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
188static 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
200static 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 */
212static void
213wakeup_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
232static 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
251static 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
264static 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 */
276static int register_wakeup_function(struct trace_array *tr, int graph, int set)
277{
278 return 0;
279}
280static void unregister_wakeup_function(struct trace_array *tr, int graph) { }
281static 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
288static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
289{
290 return TRACE_TYPE_UNHANDLED;
291}
292
293static void wakeup_trace_open(struct trace_iterator *iter) { }
294static void wakeup_trace_close(struct trace_iterator *iter) { }
295
296static void wakeup_print_header(struct seq_file *s)
297{
298 trace_default_header(s);
299}
300#endif /* !CONFIG_FUNCTION_GRAPH_TRACER */
301
302static 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
313static 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
328static 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
342static 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 */
352static 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
364static void
365probe_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
373static void
374tracing_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
401static void
402tracing_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
429static void notrace
430probe_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
492out_unlock:
493 __wakeup_reset(wakeup_trace);
494 arch_spin_unlock(&wakeup_lock);
495 local_irq_restore(flags);
496out:
497 atomic_dec(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
498}
499
500static 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
512static 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
525static void
526probe_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
596out_locked:
597 arch_spin_unlock(&wakeup_lock);
598out:
599 atomic_dec(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
600}
601
602static 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;
649fail_deprobe_sched_switch:
650 unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
651fail_deprobe_wake_new:
652 unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
653fail_deprobe:
654 unregister_trace_sched_wakeup(probe_wakeup, NULL);
655}
656
657static 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
667static bool wakeup_busy;
668
669static 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
686static 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
696static 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
706static 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
716static 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
731static void wakeup_tracer_start(struct trace_array *tr)
732{
733 wakeup_reset(tr);
734 tracer_enabled = 1;
735}
736
737static void wakeup_tracer_stop(struct trace_array *tr)
738{
739 tracer_enabled = 0;
740}
741
742static 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
762static 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
782static 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}
820core_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 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{
431 struct trace_array_cpu *data;
432 u64 T0, T1, delta;
433 unsigned long flags;
434 long disabled;
435 int cpu;
436 unsigned int trace_ctx;
437
438 tracing_record_cmdline(prev);
439
440 if (unlikely(!tracer_enabled))
441 return;
442
443 /*
444 * When we start a new trace, we set wakeup_task to NULL
445 * and then set tracer_enabled = 1. We want to make sure
446 * that another CPU does not see the tracer_enabled = 1
447 * and the wakeup_task with an older task, that might
448 * actually be the same as next.
449 */
450 smp_rmb();
451
452 if (next != wakeup_task)
453 return;
454
455 /* disable local data, not wakeup_cpu data */
456 cpu = raw_smp_processor_id();
457 disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
458 if (likely(disabled != 1))
459 goto out;
460
461 local_irq_save(flags);
462 trace_ctx = tracing_gen_ctx_flags(flags);
463
464 arch_spin_lock(&wakeup_lock);
465
466 /* We could race with grabbing wakeup_lock */
467 if (unlikely(!tracer_enabled || next != wakeup_task))
468 goto out_unlock;
469
470 /* The task we are waiting for is waking up */
471 data = per_cpu_ptr(wakeup_trace->array_buffer.data, wakeup_cpu);
472
473 __trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, trace_ctx);
474 tracing_sched_switch_trace(wakeup_trace, prev, next, trace_ctx);
475 __trace_stack(wakeup_trace, trace_ctx, 0);
476
477 T0 = data->preempt_timestamp;
478 T1 = ftrace_now(cpu);
479 delta = T1-T0;
480
481 if (!report_latency(wakeup_trace, delta))
482 goto out_unlock;
483
484 if (likely(!is_tracing_stopped())) {
485 wakeup_trace->max_latency = delta;
486 update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu, NULL);
487 }
488
489out_unlock:
490 __wakeup_reset(wakeup_trace);
491 arch_spin_unlock(&wakeup_lock);
492 local_irq_restore(flags);
493out:
494 atomic_dec(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
495}
496
497static void __wakeup_reset(struct trace_array *tr)
498{
499 wakeup_cpu = -1;
500 wakeup_prio = -1;
501 tracing_dl = false;
502
503 if (wakeup_task)
504 put_task_struct(wakeup_task);
505
506 wakeup_task = NULL;
507}
508
509static void wakeup_reset(struct trace_array *tr)
510{
511 unsigned long flags;
512
513 tracing_reset_online_cpus(&tr->array_buffer);
514
515 local_irq_save(flags);
516 arch_spin_lock(&wakeup_lock);
517 __wakeup_reset(tr);
518 arch_spin_unlock(&wakeup_lock);
519 local_irq_restore(flags);
520}
521
522static void
523probe_wakeup(void *ignore, struct task_struct *p)
524{
525 struct trace_array_cpu *data;
526 int cpu = smp_processor_id();
527 long disabled;
528 unsigned int trace_ctx;
529
530 if (likely(!tracer_enabled))
531 return;
532
533 tracing_record_cmdline(p);
534 tracing_record_cmdline(current);
535
536 /*
537 * Semantic is like this:
538 * - wakeup tracer handles all tasks in the system, independently
539 * from their scheduling class;
540 * - wakeup_rt tracer handles tasks belonging to sched_dl and
541 * sched_rt class;
542 * - wakeup_dl handles tasks belonging to sched_dl class only.
543 */
544 if (tracing_dl || (wakeup_dl && !dl_task(p)) ||
545 (wakeup_rt && !dl_task(p) && !rt_task(p)) ||
546 (!dl_task(p) && (p->prio >= wakeup_prio || p->prio >= current->prio)))
547 return;
548
549 disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
550 if (unlikely(disabled != 1))
551 goto out;
552
553 trace_ctx = tracing_gen_ctx();
554
555 /* interrupts should be off from try_to_wake_up */
556 arch_spin_lock(&wakeup_lock);
557
558 /* check for races. */
559 if (!tracer_enabled || tracing_dl ||
560 (!dl_task(p) && p->prio >= wakeup_prio))
561 goto out_locked;
562
563 /* reset the trace */
564 __wakeup_reset(wakeup_trace);
565
566 wakeup_cpu = task_cpu(p);
567 wakeup_current_cpu = wakeup_cpu;
568 wakeup_prio = p->prio;
569
570 /*
571 * Once you start tracing a -deadline task, don't bother tracing
572 * another task until the first one wakes up.
573 */
574 if (dl_task(p))
575 tracing_dl = true;
576 else
577 tracing_dl = false;
578
579 wakeup_task = get_task_struct(p);
580
581 data = per_cpu_ptr(wakeup_trace->array_buffer.data, wakeup_cpu);
582 data->preempt_timestamp = ftrace_now(cpu);
583 tracing_sched_wakeup_trace(wakeup_trace, p, current, trace_ctx);
584 __trace_stack(wakeup_trace, trace_ctx, 0);
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, trace_ctx);
592
593out_locked:
594 arch_spin_unlock(&wakeup_lock);
595out:
596 atomic_dec(&per_cpu_ptr(wakeup_trace->array_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 goto fail_deprobe_sched_switch;
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_sched_switch:
647 unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
648fail_deprobe_wake_new:
649 unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
650fail_deprobe:
651 unregister_trace_sched_wakeup(probe_wakeup, NULL);
652}
653
654static void stop_wakeup_tracer(struct trace_array *tr)
655{
656 tracer_enabled = 0;
657 stop_func_tracer(tr, is_graph(tr));
658 unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
659 unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
660 unregister_trace_sched_wakeup(probe_wakeup, NULL);
661 unregister_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
662}
663
664static bool wakeup_busy;
665
666static int __wakeup_tracer_init(struct trace_array *tr)
667{
668 save_flags = tr->trace_flags;
669
670 /* non overwrite screws up the latency tracers */
671 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
672 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
673
674 tr->max_latency = 0;
675 wakeup_trace = tr;
676 ftrace_init_array_ops(tr, wakeup_tracer_call);
677 start_wakeup_tracer(tr);
678
679 wakeup_busy = true;
680 return 0;
681}
682
683static int wakeup_tracer_init(struct trace_array *tr)
684{
685 if (wakeup_busy)
686 return -EBUSY;
687
688 wakeup_dl = false;
689 wakeup_rt = false;
690 return __wakeup_tracer_init(tr);
691}
692
693static int wakeup_rt_tracer_init(struct trace_array *tr)
694{
695 if (wakeup_busy)
696 return -EBUSY;
697
698 wakeup_dl = false;
699 wakeup_rt = true;
700 return __wakeup_tracer_init(tr);
701}
702
703static int wakeup_dl_tracer_init(struct trace_array *tr)
704{
705 if (wakeup_busy)
706 return -EBUSY;
707
708 wakeup_dl = true;
709 wakeup_rt = false;
710 return __wakeup_tracer_init(tr);
711}
712
713static void wakeup_tracer_reset(struct trace_array *tr)
714{
715 int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
716 int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
717
718 stop_wakeup_tracer(tr);
719 /* make sure we put back any tasks we are tracing */
720 wakeup_reset(tr);
721
722 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
723 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
724 ftrace_reset_array_ops(tr);
725 wakeup_busy = false;
726}
727
728static void wakeup_tracer_start(struct trace_array *tr)
729{
730 wakeup_reset(tr);
731 tracer_enabled = 1;
732}
733
734static void wakeup_tracer_stop(struct trace_array *tr)
735{
736 tracer_enabled = 0;
737}
738
739static struct tracer wakeup_tracer __read_mostly =
740{
741 .name = "wakeup",
742 .init = wakeup_tracer_init,
743 .reset = wakeup_tracer_reset,
744 .start = wakeup_tracer_start,
745 .stop = wakeup_tracer_stop,
746 .print_max = true,
747 .print_header = wakeup_print_header,
748 .print_line = wakeup_print_line,
749 .flag_changed = wakeup_flag_changed,
750#ifdef CONFIG_FTRACE_SELFTEST
751 .selftest = trace_selftest_startup_wakeup,
752#endif
753 .open = wakeup_trace_open,
754 .close = wakeup_trace_close,
755 .allow_instances = true,
756 .use_max_tr = true,
757};
758
759static struct tracer wakeup_rt_tracer __read_mostly =
760{
761 .name = "wakeup_rt",
762 .init = wakeup_rt_tracer_init,
763 .reset = wakeup_tracer_reset,
764 .start = wakeup_tracer_start,
765 .stop = wakeup_tracer_stop,
766 .print_max = true,
767 .print_header = wakeup_print_header,
768 .print_line = wakeup_print_line,
769 .flag_changed = wakeup_flag_changed,
770#ifdef CONFIG_FTRACE_SELFTEST
771 .selftest = trace_selftest_startup_wakeup,
772#endif
773 .open = wakeup_trace_open,
774 .close = wakeup_trace_close,
775 .allow_instances = true,
776 .use_max_tr = true,
777};
778
779static struct tracer wakeup_dl_tracer __read_mostly =
780{
781 .name = "wakeup_dl",
782 .init = wakeup_dl_tracer_init,
783 .reset = wakeup_tracer_reset,
784 .start = wakeup_tracer_start,
785 .stop = wakeup_tracer_stop,
786 .print_max = true,
787 .print_header = wakeup_print_header,
788 .print_line = wakeup_print_line,
789 .flag_changed = wakeup_flag_changed,
790#ifdef CONFIG_FTRACE_SELFTEST
791 .selftest = trace_selftest_startup_wakeup,
792#endif
793 .open = wakeup_trace_open,
794 .close = wakeup_trace_close,
795 .allow_instances = true,
796 .use_max_tr = true,
797};
798
799__init static int init_wakeup_tracer(void)
800{
801 int ret;
802
803 ret = register_tracer(&wakeup_tracer);
804 if (ret)
805 return ret;
806
807 ret = register_tracer(&wakeup_rt_tracer);
808 if (ret)
809 return ret;
810
811 ret = register_tracer(&wakeup_dl_tracer);
812 if (ret)
813 return ret;
814
815 return 0;
816}
817core_initcall(init_wakeup_tracer);