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12#include <linux/module.h>
13#include <linux/fs.h>
14#include <linux/debugfs.h>
15#include <linux/kallsyms.h>
16#include <linux/uaccess.h>
17#include <linux/ftrace.h>
18#include <linux/sched/rt.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;
30
31static arch_spinlock_t wakeup_lock =
32 (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
33
34static void wakeup_reset(struct trace_array *tr);
35static void __wakeup_reset(struct trace_array *tr);
36static int wakeup_graph_entry(struct ftrace_graph_ent *trace);
37static void wakeup_graph_return(struct ftrace_graph_ret *trace);
38
39static int save_flags;
40static bool function_enabled;
41
42#define TRACE_DISPLAY_GRAPH 1
43
44static struct tracer_opt trace_opts[] = {
45#ifdef CONFIG_FUNCTION_GRAPH_TRACER
46
47 { TRACER_OPT(display-graph, TRACE_DISPLAY_GRAPH) },
48#endif
49 { }
50};
51
52static struct tracer_flags tracer_flags = {
53 .val = 0,
54 .opts = trace_opts,
55};
56
57#define is_graph() (tracer_flags.val & TRACE_DISPLAY_GRAPH)
58
59#ifdef CONFIG_FUNCTION_TRACER
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75static int
76func_prolog_preempt_disable(struct trace_array *tr,
77 struct trace_array_cpu **data,
78 int *pc)
79{
80 long disabled;
81 int cpu;
82
83 if (likely(!wakeup_task))
84 return 0;
85
86 *pc = preempt_count();
87 preempt_disable_notrace();
88
89 cpu = raw_smp_processor_id();
90 if (cpu != wakeup_current_cpu)
91 goto out_enable;
92
93 *data = per_cpu_ptr(tr->trace_buffer.data, cpu);
94 disabled = atomic_inc_return(&(*data)->disabled);
95 if (unlikely(disabled != 1))
96 goto out;
97
98 return 1;
99
100out:
101 atomic_dec(&(*data)->disabled);
102
103out_enable:
104 preempt_enable_notrace();
105 return 0;
106}
107
108
109
110
111static void
112wakeup_tracer_call(unsigned long ip, unsigned long parent_ip,
113 struct ftrace_ops *op, struct pt_regs *pt_regs)
114{
115 struct trace_array *tr = wakeup_trace;
116 struct trace_array_cpu *data;
117 unsigned long flags;
118 int pc;
119
120 if (!func_prolog_preempt_disable(tr, &data, &pc))
121 return;
122
123 local_irq_save(flags);
124 trace_function(tr, ip, parent_ip, flags, pc);
125 local_irq_restore(flags);
126
127 atomic_dec(&data->disabled);
128 preempt_enable_notrace();
129}
130
131static struct ftrace_ops trace_ops __read_mostly =
132{
133 .func = wakeup_tracer_call,
134 .flags = FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_RECURSION_SAFE,
135};
136#endif
137
138static int register_wakeup_function(int graph, int set)
139{
140 int ret;
141
142
143 if (function_enabled || (!set && !(trace_flags & TRACE_ITER_FUNCTION)))
144 return 0;
145
146 if (graph)
147 ret = register_ftrace_graph(&wakeup_graph_return,
148 &wakeup_graph_entry);
149 else
150 ret = register_ftrace_function(&trace_ops);
151
152 if (!ret)
153 function_enabled = true;
154
155 return ret;
156}
157
158static void unregister_wakeup_function(int graph)
159{
160 if (!function_enabled)
161 return;
162
163 if (graph)
164 unregister_ftrace_graph();
165 else
166 unregister_ftrace_function(&trace_ops);
167
168 function_enabled = false;
169}
170
171static void wakeup_function_set(int set)
172{
173 if (set)
174 register_wakeup_function(is_graph(), 1);
175 else
176 unregister_wakeup_function(is_graph());
177}
178
179static int wakeup_flag_changed(struct tracer *tracer, u32 mask, int set)
180{
181 if (mask & TRACE_ITER_FUNCTION)
182 wakeup_function_set(set);
183
184 return trace_keep_overwrite(tracer, mask, set);
185}
186
187static int start_func_tracer(int graph)
188{
189 int ret;
190
191 ret = register_wakeup_function(graph, 0);
192
193 if (!ret && tracing_is_enabled())
194 tracer_enabled = 1;
195 else
196 tracer_enabled = 0;
197
198 return ret;
199}
200
201static void stop_func_tracer(int graph)
202{
203 tracer_enabled = 0;
204
205 unregister_wakeup_function(graph);
206}
207
208#ifdef CONFIG_FUNCTION_GRAPH_TRACER
209static int wakeup_set_flag(u32 old_flags, u32 bit, int set)
210{
211
212 if (!(bit & TRACE_DISPLAY_GRAPH))
213 return -EINVAL;
214
215 if (!(is_graph() ^ set))
216 return 0;
217
218 stop_func_tracer(!set);
219
220 wakeup_reset(wakeup_trace);
221 tracing_max_latency = 0;
222
223 return start_func_tracer(set);
224}
225
226static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
227{
228 struct trace_array *tr = wakeup_trace;
229 struct trace_array_cpu *data;
230 unsigned long flags;
231 int pc, ret = 0;
232
233 if (!func_prolog_preempt_disable(tr, &data, &pc))
234 return 0;
235
236 local_save_flags(flags);
237 ret = __trace_graph_entry(tr, trace, flags, pc);
238 atomic_dec(&data->disabled);
239 preempt_enable_notrace();
240
241 return ret;
242}
243
244static void wakeup_graph_return(struct ftrace_graph_ret *trace)
245{
246 struct trace_array *tr = wakeup_trace;
247 struct trace_array_cpu *data;
248 unsigned long flags;
249 int pc;
250
251 if (!func_prolog_preempt_disable(tr, &data, &pc))
252 return;
253
254 local_save_flags(flags);
255 __trace_graph_return(tr, trace, flags, pc);
256 atomic_dec(&data->disabled);
257
258 preempt_enable_notrace();
259 return;
260}
261
262static void wakeup_trace_open(struct trace_iterator *iter)
263{
264 if (is_graph())
265 graph_trace_open(iter);
266}
267
268static void wakeup_trace_close(struct trace_iterator *iter)
269{
270 if (iter->private)
271 graph_trace_close(iter);
272}
273
274#define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_PROC | \
275 TRACE_GRAPH_PRINT_ABS_TIME | \
276 TRACE_GRAPH_PRINT_DURATION)
277
278static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
279{
280
281
282
283
284 if (is_graph())
285 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
286
287 return TRACE_TYPE_UNHANDLED;
288}
289
290static void wakeup_print_header(struct seq_file *s)
291{
292 if (is_graph())
293 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
294 else
295 trace_default_header(s);
296}
297
298static void
299__trace_function(struct trace_array *tr,
300 unsigned long ip, unsigned long parent_ip,
301 unsigned long flags, int pc)
302{
303 if (is_graph())
304 trace_graph_function(tr, ip, parent_ip, flags, pc);
305 else
306 trace_function(tr, ip, parent_ip, flags, pc);
307}
308#else
309#define __trace_function trace_function
310
311static int wakeup_set_flag(u32 old_flags, u32 bit, int set)
312{
313 return -EINVAL;
314}
315
316static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
317{
318 return -1;
319}
320
321static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
322{
323 return TRACE_TYPE_UNHANDLED;
324}
325
326static void wakeup_graph_return(struct ftrace_graph_ret *trace) { }
327static void wakeup_trace_open(struct trace_iterator *iter) { }
328static void wakeup_trace_close(struct trace_iterator *iter) { }
329
330#ifdef CONFIG_FUNCTION_TRACER
331static void wakeup_print_header(struct seq_file *s)
332{
333 trace_default_header(s);
334}
335#else
336static void wakeup_print_header(struct seq_file *s)
337{
338 trace_latency_header(s);
339}
340#endif
341#endif
342
343
344
345
346static int report_latency(cycle_t delta)
347{
348 if (tracing_thresh) {
349 if (delta < tracing_thresh)
350 return 0;
351 } else {
352 if (delta <= tracing_max_latency)
353 return 0;
354 }
355 return 1;
356}
357
358static void
359probe_wakeup_migrate_task(void *ignore, struct task_struct *task, int cpu)
360{
361 if (task != wakeup_task)
362 return;
363
364 wakeup_current_cpu = cpu;
365}
366
367static void notrace
368probe_wakeup_sched_switch(void *ignore,
369 struct task_struct *prev, struct task_struct *next)
370{
371 struct trace_array_cpu *data;
372 cycle_t T0, T1, delta;
373 unsigned long flags;
374 long disabled;
375 int cpu;
376 int pc;
377
378 tracing_record_cmdline(prev);
379
380 if (unlikely(!tracer_enabled))
381 return;
382
383
384
385
386
387
388
389
390 smp_rmb();
391
392 if (next != wakeup_task)
393 return;
394
395 pc = preempt_count();
396
397
398 cpu = raw_smp_processor_id();
399 disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
400 if (likely(disabled != 1))
401 goto out;
402
403 local_irq_save(flags);
404 arch_spin_lock(&wakeup_lock);
405
406
407 if (unlikely(!tracer_enabled || next != wakeup_task))
408 goto out_unlock;
409
410
411 data = per_cpu_ptr(wakeup_trace->trace_buffer.data, wakeup_cpu);
412
413 __trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, flags, pc);
414 tracing_sched_switch_trace(wakeup_trace, prev, next, flags, pc);
415
416 T0 = data->preempt_timestamp;
417 T1 = ftrace_now(cpu);
418 delta = T1-T0;
419
420 if (!report_latency(delta))
421 goto out_unlock;
422
423 if (likely(!is_tracing_stopped())) {
424 tracing_max_latency = delta;
425 update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu);
426 }
427
428out_unlock:
429 __wakeup_reset(wakeup_trace);
430 arch_spin_unlock(&wakeup_lock);
431 local_irq_restore(flags);
432out:
433 atomic_dec(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
434}
435
436static void __wakeup_reset(struct trace_array *tr)
437{
438 wakeup_cpu = -1;
439 wakeup_prio = -1;
440
441 if (wakeup_task)
442 put_task_struct(wakeup_task);
443
444 wakeup_task = NULL;
445}
446
447static void wakeup_reset(struct trace_array *tr)
448{
449 unsigned long flags;
450
451 tracing_reset_online_cpus(&tr->trace_buffer);
452
453 local_irq_save(flags);
454 arch_spin_lock(&wakeup_lock);
455 __wakeup_reset(tr);
456 arch_spin_unlock(&wakeup_lock);
457 local_irq_restore(flags);
458}
459
460static void
461probe_wakeup(void *ignore, struct task_struct *p, int success)
462{
463 struct trace_array_cpu *data;
464 int cpu = smp_processor_id();
465 unsigned long flags;
466 long disabled;
467 int pc;
468
469 if (likely(!tracer_enabled))
470 return;
471
472 tracing_record_cmdline(p);
473 tracing_record_cmdline(current);
474
475 if ((wakeup_rt && !rt_task(p)) ||
476 p->prio >= wakeup_prio ||
477 p->prio >= current->prio)
478 return;
479
480 pc = preempt_count();
481 disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
482 if (unlikely(disabled != 1))
483 goto out;
484
485
486 arch_spin_lock(&wakeup_lock);
487
488
489 if (!tracer_enabled || p->prio >= wakeup_prio)
490 goto out_locked;
491
492
493 __wakeup_reset(wakeup_trace);
494
495 wakeup_cpu = task_cpu(p);
496 wakeup_current_cpu = wakeup_cpu;
497 wakeup_prio = p->prio;
498
499 wakeup_task = p;
500 get_task_struct(wakeup_task);
501
502 local_save_flags(flags);
503
504 data = per_cpu_ptr(wakeup_trace->trace_buffer.data, wakeup_cpu);
505 data->preempt_timestamp = ftrace_now(cpu);
506 tracing_sched_wakeup_trace(wakeup_trace, p, current, flags, pc);
507
508
509
510
511
512
513 __trace_function(wakeup_trace, CALLER_ADDR1, CALLER_ADDR2, flags, pc);
514
515out_locked:
516 arch_spin_unlock(&wakeup_lock);
517out:
518 atomic_dec(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
519}
520
521static void start_wakeup_tracer(struct trace_array *tr)
522{
523 int ret;
524
525 ret = register_trace_sched_wakeup(probe_wakeup, NULL);
526 if (ret) {
527 pr_info("wakeup trace: Couldn't activate tracepoint"
528 " probe to kernel_sched_wakeup\n");
529 return;
530 }
531
532 ret = register_trace_sched_wakeup_new(probe_wakeup, NULL);
533 if (ret) {
534 pr_info("wakeup trace: Couldn't activate tracepoint"
535 " probe to kernel_sched_wakeup_new\n");
536 goto fail_deprobe;
537 }
538
539 ret = register_trace_sched_switch(probe_wakeup_sched_switch, NULL);
540 if (ret) {
541 pr_info("sched trace: Couldn't activate tracepoint"
542 " probe to kernel_sched_switch\n");
543 goto fail_deprobe_wake_new;
544 }
545
546 ret = register_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
547 if (ret) {
548 pr_info("wakeup trace: Couldn't activate tracepoint"
549 " probe to kernel_sched_migrate_task\n");
550 return;
551 }
552
553 wakeup_reset(tr);
554
555
556
557
558
559
560
561
562 smp_wmb();
563
564 if (start_func_tracer(is_graph()))
565 printk(KERN_ERR "failed to start wakeup tracer\n");
566
567 return;
568fail_deprobe_wake_new:
569 unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
570fail_deprobe:
571 unregister_trace_sched_wakeup(probe_wakeup, NULL);
572}
573
574static void stop_wakeup_tracer(struct trace_array *tr)
575{
576 tracer_enabled = 0;
577 stop_func_tracer(is_graph());
578 unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
579 unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
580 unregister_trace_sched_wakeup(probe_wakeup, NULL);
581 unregister_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
582}
583
584static int __wakeup_tracer_init(struct trace_array *tr)
585{
586 save_flags = trace_flags;
587
588
589 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
590 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
591
592 tracing_max_latency = 0;
593 wakeup_trace = tr;
594 start_wakeup_tracer(tr);
595 return 0;
596}
597
598static int wakeup_tracer_init(struct trace_array *tr)
599{
600 wakeup_rt = 0;
601 return __wakeup_tracer_init(tr);
602}
603
604static int wakeup_rt_tracer_init(struct trace_array *tr)
605{
606 wakeup_rt = 1;
607 return __wakeup_tracer_init(tr);
608}
609
610static void wakeup_tracer_reset(struct trace_array *tr)
611{
612 int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
613 int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
614
615 stop_wakeup_tracer(tr);
616
617 wakeup_reset(tr);
618
619 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
620 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
621}
622
623static void wakeup_tracer_start(struct trace_array *tr)
624{
625 wakeup_reset(tr);
626 tracer_enabled = 1;
627}
628
629static void wakeup_tracer_stop(struct trace_array *tr)
630{
631 tracer_enabled = 0;
632}
633
634static struct tracer wakeup_tracer __read_mostly =
635{
636 .name = "wakeup",
637 .init = wakeup_tracer_init,
638 .reset = wakeup_tracer_reset,
639 .start = wakeup_tracer_start,
640 .stop = wakeup_tracer_stop,
641 .print_max = true,
642 .print_header = wakeup_print_header,
643 .print_line = wakeup_print_line,
644 .flags = &tracer_flags,
645 .set_flag = wakeup_set_flag,
646 .flag_changed = wakeup_flag_changed,
647#ifdef CONFIG_FTRACE_SELFTEST
648 .selftest = trace_selftest_startup_wakeup,
649#endif
650 .open = wakeup_trace_open,
651 .close = wakeup_trace_close,
652 .use_max_tr = true,
653};
654
655static struct tracer wakeup_rt_tracer __read_mostly =
656{
657 .name = "wakeup_rt",
658 .init = wakeup_rt_tracer_init,
659 .reset = wakeup_tracer_reset,
660 .start = wakeup_tracer_start,
661 .stop = wakeup_tracer_stop,
662 .wait_pipe = poll_wait_pipe,
663 .print_max = true,
664 .print_header = wakeup_print_header,
665 .print_line = wakeup_print_line,
666 .flags = &tracer_flags,
667 .set_flag = wakeup_set_flag,
668 .flag_changed = wakeup_flag_changed,
669#ifdef CONFIG_FTRACE_SELFTEST
670 .selftest = trace_selftest_startup_wakeup,
671#endif
672 .open = wakeup_trace_open,
673 .close = wakeup_trace_close,
674 .use_max_tr = true,
675};
676
677__init static int init_wakeup_tracer(void)
678{
679 int ret;
680
681 ret = register_tracer(&wakeup_tracer);
682 if (ret)
683 return ret;
684
685 ret = register_tracer(&wakeup_rt_tracer);
686 if (ret)
687 return ret;
688
689 return 0;
690}
691core_initcall(init_wakeup_tracer);
692