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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * trace irqs off critical timings
4 *
5 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
6 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
7 *
8 * From code in the latency_tracer, that is:
9 *
10 * Copyright (C) 2004-2006 Ingo Molnar
11 * Copyright (C) 2004 Nadia Yvette Chambers
12 */
13#include <linux/kallsyms.h>
14#include <linux/uaccess.h>
15#include <linux/module.h>
16#include <linux/ftrace.h>
17#include <linux/kprobes.h>
18
19#include "trace.h"
20
21#include <trace/events/preemptirq.h>
22
23#if defined(CONFIG_IRQSOFF_TRACER) || defined(CONFIG_PREEMPT_TRACER)
24static struct trace_array *irqsoff_trace __read_mostly;
25static int tracer_enabled __read_mostly;
26
27static DEFINE_PER_CPU(int, tracing_cpu);
28
29static DEFINE_RAW_SPINLOCK(max_trace_lock);
30
31enum {
32 TRACER_IRQS_OFF = (1 << 1),
33 TRACER_PREEMPT_OFF = (1 << 2),
34};
35
36static int trace_type __read_mostly;
37
38static int save_flags;
39
40static void stop_irqsoff_tracer(struct trace_array *tr, int graph);
41static int start_irqsoff_tracer(struct trace_array *tr, int graph);
42
43#ifdef CONFIG_PREEMPT_TRACER
44static inline int
45preempt_trace(int pc)
46{
47 return ((trace_type & TRACER_PREEMPT_OFF) && pc);
48}
49#else
50# define preempt_trace(pc) (0)
51#endif
52
53#ifdef CONFIG_IRQSOFF_TRACER
54static inline int
55irq_trace(void)
56{
57 return ((trace_type & TRACER_IRQS_OFF) &&
58 irqs_disabled());
59}
60#else
61# define irq_trace() (0)
62#endif
63
64#ifdef CONFIG_FUNCTION_GRAPH_TRACER
65static int irqsoff_display_graph(struct trace_array *tr, int set);
66# define is_graph(tr) ((tr)->trace_flags & TRACE_ITER_DISPLAY_GRAPH)
67#else
68static inline int irqsoff_display_graph(struct trace_array *tr, int set)
69{
70 return -EINVAL;
71}
72# define is_graph(tr) false
73#endif
74
75/*
76 * Sequence count - we record it when starting a measurement and
77 * skip the latency if the sequence has changed - some other section
78 * did a maximum and could disturb our measurement with serial console
79 * printouts, etc. Truly coinciding maximum latencies should be rare
80 * and what happens together happens separately as well, so this doesn't
81 * decrease the validity of the maximum found:
82 */
83static __cacheline_aligned_in_smp unsigned long max_sequence;
84
85#ifdef CONFIG_FUNCTION_TRACER
86/*
87 * Prologue for the preempt and irqs off function tracers.
88 *
89 * Returns 1 if it is OK to continue, and data->disabled is
90 * incremented.
91 * 0 if the trace is to be ignored, and data->disabled
92 * is kept the same.
93 *
94 * Note, this function is also used outside this ifdef but
95 * inside the #ifdef of the function graph tracer below.
96 * This is OK, since the function graph tracer is
97 * dependent on the function tracer.
98 */
99static int func_prolog_dec(struct trace_array *tr,
100 struct trace_array_cpu **data,
101 unsigned long *flags)
102{
103 long disabled;
104 int cpu;
105
106 /*
107 * Does not matter if we preempt. We test the flags
108 * afterward, to see if irqs are disabled or not.
109 * If we preempt and get a false positive, the flags
110 * test will fail.
111 */
112 cpu = raw_smp_processor_id();
113 if (likely(!per_cpu(tracing_cpu, cpu)))
114 return 0;
115
116 local_save_flags(*flags);
117 /*
118 * Slight chance to get a false positive on tracing_cpu,
119 * although I'm starting to think there isn't a chance.
120 * Leave this for now just to be paranoid.
121 */
122 if (!irqs_disabled_flags(*flags) && !preempt_count())
123 return 0;
124
125 *data = per_cpu_ptr(tr->array_buffer.data, cpu);
126 disabled = atomic_inc_return(&(*data)->disabled);
127
128 if (likely(disabled == 1))
129 return 1;
130
131 atomic_dec(&(*data)->disabled);
132
133 return 0;
134}
135
136/*
137 * irqsoff uses its own tracer function to keep the overhead down:
138 */
139static void
140irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip,
141 struct ftrace_ops *op, struct ftrace_regs *fregs)
142{
143 struct trace_array *tr = irqsoff_trace;
144 struct trace_array_cpu *data;
145 unsigned long flags;
146 unsigned int trace_ctx;
147
148 if (!func_prolog_dec(tr, &data, &flags))
149 return;
150
151 trace_ctx = tracing_gen_ctx_flags(flags);
152
153 trace_function(tr, ip, parent_ip, trace_ctx);
154
155 atomic_dec(&data->disabled);
156}
157#endif /* CONFIG_FUNCTION_TRACER */
158
159#ifdef CONFIG_FUNCTION_GRAPH_TRACER
160static int irqsoff_display_graph(struct trace_array *tr, int set)
161{
162 int cpu;
163
164 if (!(is_graph(tr) ^ set))
165 return 0;
166
167 stop_irqsoff_tracer(irqsoff_trace, !set);
168
169 for_each_possible_cpu(cpu)
170 per_cpu(tracing_cpu, cpu) = 0;
171
172 tr->max_latency = 0;
173 tracing_reset_online_cpus(&irqsoff_trace->array_buffer);
174
175 return start_irqsoff_tracer(irqsoff_trace, set);
176}
177
178static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
179{
180 struct trace_array *tr = irqsoff_trace;
181 struct trace_array_cpu *data;
182 unsigned long flags;
183 unsigned int trace_ctx;
184 int ret;
185
186 if (ftrace_graph_ignore_func(trace))
187 return 0;
188 /*
189 * Do not trace a function if it's filtered by set_graph_notrace.
190 * Make the index of ret stack negative to indicate that it should
191 * ignore further functions. But it needs its own ret stack entry
192 * to recover the original index in order to continue tracing after
193 * returning from the function.
194 */
195 if (ftrace_graph_notrace_addr(trace->func))
196 return 1;
197
198 if (!func_prolog_dec(tr, &data, &flags))
199 return 0;
200
201 trace_ctx = tracing_gen_ctx_flags(flags);
202 ret = __trace_graph_entry(tr, trace, trace_ctx);
203 atomic_dec(&data->disabled);
204
205 return ret;
206}
207
208static void irqsoff_graph_return(struct ftrace_graph_ret *trace)
209{
210 struct trace_array *tr = irqsoff_trace;
211 struct trace_array_cpu *data;
212 unsigned long flags;
213 unsigned int trace_ctx;
214
215 ftrace_graph_addr_finish(trace);
216
217 if (!func_prolog_dec(tr, &data, &flags))
218 return;
219
220 trace_ctx = tracing_gen_ctx_flags(flags);
221 __trace_graph_return(tr, trace, trace_ctx);
222 atomic_dec(&data->disabled);
223}
224
225static struct fgraph_ops fgraph_ops = {
226 .entryfunc = &irqsoff_graph_entry,
227 .retfunc = &irqsoff_graph_return,
228};
229
230static void irqsoff_trace_open(struct trace_iterator *iter)
231{
232 if (is_graph(iter->tr))
233 graph_trace_open(iter);
234
235}
236
237static void irqsoff_trace_close(struct trace_iterator *iter)
238{
239 if (iter->private)
240 graph_trace_close(iter);
241}
242
243#define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_CPU | \
244 TRACE_GRAPH_PRINT_PROC | \
245 TRACE_GRAPH_PRINT_REL_TIME | \
246 TRACE_GRAPH_PRINT_DURATION)
247
248static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
249{
250 /*
251 * In graph mode call the graph tracer output function,
252 * otherwise go with the TRACE_FN event handler
253 */
254 if (is_graph(iter->tr))
255 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
256
257 return TRACE_TYPE_UNHANDLED;
258}
259
260static void irqsoff_print_header(struct seq_file *s)
261{
262 struct trace_array *tr = irqsoff_trace;
263
264 if (is_graph(tr))
265 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
266 else
267 trace_default_header(s);
268}
269
270static void
271__trace_function(struct trace_array *tr,
272 unsigned long ip, unsigned long parent_ip,
273 unsigned int trace_ctx)
274{
275 if (is_graph(tr))
276 trace_graph_function(tr, ip, parent_ip, trace_ctx);
277 else
278 trace_function(tr, ip, parent_ip, trace_ctx);
279}
280
281#else
282#define __trace_function trace_function
283
284static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
285{
286 return TRACE_TYPE_UNHANDLED;
287}
288
289static void irqsoff_trace_open(struct trace_iterator *iter) { }
290static void irqsoff_trace_close(struct trace_iterator *iter) { }
291
292#ifdef CONFIG_FUNCTION_TRACER
293static void irqsoff_print_header(struct seq_file *s)
294{
295 trace_default_header(s);
296}
297#else
298static void irqsoff_print_header(struct seq_file *s)
299{
300 trace_latency_header(s);
301}
302#endif /* CONFIG_FUNCTION_TRACER */
303#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
304
305/*
306 * Should this new latency be reported/recorded?
307 */
308static bool report_latency(struct trace_array *tr, u64 delta)
309{
310 if (tracing_thresh) {
311 if (delta < tracing_thresh)
312 return false;
313 } else {
314 if (delta <= tr->max_latency)
315 return false;
316 }
317 return true;
318}
319
320static void
321check_critical_timing(struct trace_array *tr,
322 struct trace_array_cpu *data,
323 unsigned long parent_ip,
324 int cpu)
325{
326 u64 T0, T1, delta;
327 unsigned long flags;
328 unsigned int trace_ctx;
329
330 T0 = data->preempt_timestamp;
331 T1 = ftrace_now(cpu);
332 delta = T1-T0;
333
334 trace_ctx = tracing_gen_ctx();
335
336 if (!report_latency(tr, delta))
337 goto out;
338
339 raw_spin_lock_irqsave(&max_trace_lock, flags);
340
341 /* check if we are still the max latency */
342 if (!report_latency(tr, delta))
343 goto out_unlock;
344
345 __trace_function(tr, CALLER_ADDR0, parent_ip, trace_ctx);
346 /* Skip 5 functions to get to the irq/preempt enable function */
347 __trace_stack(tr, trace_ctx, 5);
348
349 if (data->critical_sequence != max_sequence)
350 goto out_unlock;
351
352 data->critical_end = parent_ip;
353
354 if (likely(!is_tracing_stopped())) {
355 tr->max_latency = delta;
356 update_max_tr_single(tr, current, cpu);
357 }
358
359 max_sequence++;
360
361out_unlock:
362 raw_spin_unlock_irqrestore(&max_trace_lock, flags);
363
364out:
365 data->critical_sequence = max_sequence;
366 data->preempt_timestamp = ftrace_now(cpu);
367 __trace_function(tr, CALLER_ADDR0, parent_ip, trace_ctx);
368}
369
370static nokprobe_inline void
371start_critical_timing(unsigned long ip, unsigned long parent_ip)
372{
373 int cpu;
374 struct trace_array *tr = irqsoff_trace;
375 struct trace_array_cpu *data;
376
377 if (!tracer_enabled || !tracing_is_enabled())
378 return;
379
380 cpu = raw_smp_processor_id();
381
382 if (per_cpu(tracing_cpu, cpu))
383 return;
384
385 data = per_cpu_ptr(tr->array_buffer.data, cpu);
386
387 if (unlikely(!data) || atomic_read(&data->disabled))
388 return;
389
390 atomic_inc(&data->disabled);
391
392 data->critical_sequence = max_sequence;
393 data->preempt_timestamp = ftrace_now(cpu);
394 data->critical_start = parent_ip ? : ip;
395
396 __trace_function(tr, ip, parent_ip, tracing_gen_ctx());
397
398 per_cpu(tracing_cpu, cpu) = 1;
399
400 atomic_dec(&data->disabled);
401}
402
403static nokprobe_inline void
404stop_critical_timing(unsigned long ip, unsigned long parent_ip)
405{
406 int cpu;
407 struct trace_array *tr = irqsoff_trace;
408 struct trace_array_cpu *data;
409 unsigned int trace_ctx;
410
411 cpu = raw_smp_processor_id();
412 /* Always clear the tracing cpu on stopping the trace */
413 if (unlikely(per_cpu(tracing_cpu, cpu)))
414 per_cpu(tracing_cpu, cpu) = 0;
415 else
416 return;
417
418 if (!tracer_enabled || !tracing_is_enabled())
419 return;
420
421 data = per_cpu_ptr(tr->array_buffer.data, cpu);
422
423 if (unlikely(!data) ||
424 !data->critical_start || atomic_read(&data->disabled))
425 return;
426
427 atomic_inc(&data->disabled);
428
429 trace_ctx = tracing_gen_ctx();
430 __trace_function(tr, ip, parent_ip, trace_ctx);
431 check_critical_timing(tr, data, parent_ip ? : ip, cpu);
432 data->critical_start = 0;
433 atomic_dec(&data->disabled);
434}
435
436/* start and stop critical timings used to for stoppage (in idle) */
437void start_critical_timings(void)
438{
439 if (preempt_trace(preempt_count()) || irq_trace())
440 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
441}
442EXPORT_SYMBOL_GPL(start_critical_timings);
443NOKPROBE_SYMBOL(start_critical_timings);
444
445void stop_critical_timings(void)
446{
447 if (preempt_trace(preempt_count()) || irq_trace())
448 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
449}
450EXPORT_SYMBOL_GPL(stop_critical_timings);
451NOKPROBE_SYMBOL(stop_critical_timings);
452
453#ifdef CONFIG_FUNCTION_TRACER
454static bool function_enabled;
455
456static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
457{
458 int ret;
459
460 /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
461 if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION)))
462 return 0;
463
464 if (graph)
465 ret = register_ftrace_graph(&fgraph_ops);
466 else
467 ret = register_ftrace_function(tr->ops);
468
469 if (!ret)
470 function_enabled = true;
471
472 return ret;
473}
474
475static void unregister_irqsoff_function(struct trace_array *tr, int graph)
476{
477 if (!function_enabled)
478 return;
479
480 if (graph)
481 unregister_ftrace_graph(&fgraph_ops);
482 else
483 unregister_ftrace_function(tr->ops);
484
485 function_enabled = false;
486}
487
488static int irqsoff_function_set(struct trace_array *tr, u32 mask, int set)
489{
490 if (!(mask & TRACE_ITER_FUNCTION))
491 return 0;
492
493 if (set)
494 register_irqsoff_function(tr, is_graph(tr), 1);
495 else
496 unregister_irqsoff_function(tr, is_graph(tr));
497 return 1;
498}
499#else
500static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
501{
502 return 0;
503}
504static void unregister_irqsoff_function(struct trace_array *tr, int graph) { }
505static inline int irqsoff_function_set(struct trace_array *tr, u32 mask, int set)
506{
507 return 0;
508}
509#endif /* CONFIG_FUNCTION_TRACER */
510
511static int irqsoff_flag_changed(struct trace_array *tr, u32 mask, int set)
512{
513 struct tracer *tracer = tr->current_trace;
514
515 if (irqsoff_function_set(tr, mask, set))
516 return 0;
517
518#ifdef CONFIG_FUNCTION_GRAPH_TRACER
519 if (mask & TRACE_ITER_DISPLAY_GRAPH)
520 return irqsoff_display_graph(tr, set);
521#endif
522
523 return trace_keep_overwrite(tracer, mask, set);
524}
525
526static int start_irqsoff_tracer(struct trace_array *tr, int graph)
527{
528 int ret;
529
530 ret = register_irqsoff_function(tr, graph, 0);
531
532 if (!ret && tracing_is_enabled())
533 tracer_enabled = 1;
534 else
535 tracer_enabled = 0;
536
537 return ret;
538}
539
540static void stop_irqsoff_tracer(struct trace_array *tr, int graph)
541{
542 tracer_enabled = 0;
543
544 unregister_irqsoff_function(tr, graph);
545}
546
547static bool irqsoff_busy;
548
549static int __irqsoff_tracer_init(struct trace_array *tr)
550{
551 if (irqsoff_busy)
552 return -EBUSY;
553
554 save_flags = tr->trace_flags;
555
556 /* non overwrite screws up the latency tracers */
557 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
558 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
559 /* without pause, we will produce garbage if another latency occurs */
560 set_tracer_flag(tr, TRACE_ITER_PAUSE_ON_TRACE, 1);
561
562 tr->max_latency = 0;
563 irqsoff_trace = tr;
564 /* make sure that the tracer is visible */
565 smp_wmb();
566
567 ftrace_init_array_ops(tr, irqsoff_tracer_call);
568
569 /* Only toplevel instance supports graph tracing */
570 if (start_irqsoff_tracer(tr, (tr->flags & TRACE_ARRAY_FL_GLOBAL &&
571 is_graph(tr))))
572 printk(KERN_ERR "failed to start irqsoff tracer\n");
573
574 irqsoff_busy = true;
575 return 0;
576}
577
578static void __irqsoff_tracer_reset(struct trace_array *tr)
579{
580 int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
581 int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
582 int pause_flag = save_flags & TRACE_ITER_PAUSE_ON_TRACE;
583
584 stop_irqsoff_tracer(tr, is_graph(tr));
585
586 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
587 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
588 set_tracer_flag(tr, TRACE_ITER_PAUSE_ON_TRACE, pause_flag);
589 ftrace_reset_array_ops(tr);
590
591 irqsoff_busy = false;
592}
593
594static void irqsoff_tracer_start(struct trace_array *tr)
595{
596 tracer_enabled = 1;
597}
598
599static void irqsoff_tracer_stop(struct trace_array *tr)
600{
601 tracer_enabled = 0;
602}
603
604#ifdef CONFIG_IRQSOFF_TRACER
605/*
606 * We are only interested in hardirq on/off events:
607 */
608void tracer_hardirqs_on(unsigned long a0, unsigned long a1)
609{
610 if (!preempt_trace(preempt_count()) && irq_trace())
611 stop_critical_timing(a0, a1);
612}
613NOKPROBE_SYMBOL(tracer_hardirqs_on);
614
615void tracer_hardirqs_off(unsigned long a0, unsigned long a1)
616{
617 if (!preempt_trace(preempt_count()) && irq_trace())
618 start_critical_timing(a0, a1);
619}
620NOKPROBE_SYMBOL(tracer_hardirqs_off);
621
622static int irqsoff_tracer_init(struct trace_array *tr)
623{
624 trace_type = TRACER_IRQS_OFF;
625
626 return __irqsoff_tracer_init(tr);
627}
628
629static void irqsoff_tracer_reset(struct trace_array *tr)
630{
631 __irqsoff_tracer_reset(tr);
632}
633
634static struct tracer irqsoff_tracer __read_mostly =
635{
636 .name = "irqsoff",
637 .init = irqsoff_tracer_init,
638 .reset = irqsoff_tracer_reset,
639 .start = irqsoff_tracer_start,
640 .stop = irqsoff_tracer_stop,
641 .print_max = true,
642 .print_header = irqsoff_print_header,
643 .print_line = irqsoff_print_line,
644 .flag_changed = irqsoff_flag_changed,
645#ifdef CONFIG_FTRACE_SELFTEST
646 .selftest = trace_selftest_startup_irqsoff,
647#endif
648 .open = irqsoff_trace_open,
649 .close = irqsoff_trace_close,
650 .allow_instances = true,
651 .use_max_tr = true,
652};
653#endif /* CONFIG_IRQSOFF_TRACER */
654
655#ifdef CONFIG_PREEMPT_TRACER
656void tracer_preempt_on(unsigned long a0, unsigned long a1)
657{
658 if (preempt_trace(preempt_count()) && !irq_trace())
659 stop_critical_timing(a0, a1);
660}
661
662void tracer_preempt_off(unsigned long a0, unsigned long a1)
663{
664 if (preempt_trace(preempt_count()) && !irq_trace())
665 start_critical_timing(a0, a1);
666}
667
668static int preemptoff_tracer_init(struct trace_array *tr)
669{
670 trace_type = TRACER_PREEMPT_OFF;
671
672 return __irqsoff_tracer_init(tr);
673}
674
675static void preemptoff_tracer_reset(struct trace_array *tr)
676{
677 __irqsoff_tracer_reset(tr);
678}
679
680static struct tracer preemptoff_tracer __read_mostly =
681{
682 .name = "preemptoff",
683 .init = preemptoff_tracer_init,
684 .reset = preemptoff_tracer_reset,
685 .start = irqsoff_tracer_start,
686 .stop = irqsoff_tracer_stop,
687 .print_max = true,
688 .print_header = irqsoff_print_header,
689 .print_line = irqsoff_print_line,
690 .flag_changed = irqsoff_flag_changed,
691#ifdef CONFIG_FTRACE_SELFTEST
692 .selftest = trace_selftest_startup_preemptoff,
693#endif
694 .open = irqsoff_trace_open,
695 .close = irqsoff_trace_close,
696 .allow_instances = true,
697 .use_max_tr = true,
698};
699#endif /* CONFIG_PREEMPT_TRACER */
700
701#if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
702
703static int preemptirqsoff_tracer_init(struct trace_array *tr)
704{
705 trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF;
706
707 return __irqsoff_tracer_init(tr);
708}
709
710static void preemptirqsoff_tracer_reset(struct trace_array *tr)
711{
712 __irqsoff_tracer_reset(tr);
713}
714
715static struct tracer preemptirqsoff_tracer __read_mostly =
716{
717 .name = "preemptirqsoff",
718 .init = preemptirqsoff_tracer_init,
719 .reset = preemptirqsoff_tracer_reset,
720 .start = irqsoff_tracer_start,
721 .stop = irqsoff_tracer_stop,
722 .print_max = true,
723 .print_header = irqsoff_print_header,
724 .print_line = irqsoff_print_line,
725 .flag_changed = irqsoff_flag_changed,
726#ifdef CONFIG_FTRACE_SELFTEST
727 .selftest = trace_selftest_startup_preemptirqsoff,
728#endif
729 .open = irqsoff_trace_open,
730 .close = irqsoff_trace_close,
731 .allow_instances = true,
732 .use_max_tr = true,
733};
734#endif
735
736__init static int init_irqsoff_tracer(void)
737{
738#ifdef CONFIG_IRQSOFF_TRACER
739 register_tracer(&irqsoff_tracer);
740#endif
741#ifdef CONFIG_PREEMPT_TRACER
742 register_tracer(&preemptoff_tracer);
743#endif
744#if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
745 register_tracer(&preemptirqsoff_tracer);
746#endif
747
748 return 0;
749}
750core_initcall(init_irqsoff_tracer);
751#endif /* IRQSOFF_TRACER || PREEMPTOFF_TRACER */
1/*
2 * trace irqs off critical timings
3 *
4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
6 *
7 * From code in the latency_tracer, that is:
8 *
9 * Copyright (C) 2004-2006 Ingo Molnar
10 * Copyright (C) 2004 Nadia Yvette Chambers
11 */
12#include <linux/kallsyms.h>
13#include <linux/uaccess.h>
14#include <linux/module.h>
15#include <linux/ftrace.h>
16
17#include "trace.h"
18
19#define CREATE_TRACE_POINTS
20#include <trace/events/preemptirq.h>
21
22#if defined(CONFIG_IRQSOFF_TRACER) || defined(CONFIG_PREEMPT_TRACER)
23static struct trace_array *irqsoff_trace __read_mostly;
24static int tracer_enabled __read_mostly;
25
26static DEFINE_PER_CPU(int, tracing_cpu);
27
28static DEFINE_RAW_SPINLOCK(max_trace_lock);
29
30enum {
31 TRACER_IRQS_OFF = (1 << 1),
32 TRACER_PREEMPT_OFF = (1 << 2),
33};
34
35static int trace_type __read_mostly;
36
37static int save_flags;
38
39static void stop_irqsoff_tracer(struct trace_array *tr, int graph);
40static int start_irqsoff_tracer(struct trace_array *tr, int graph);
41
42#ifdef CONFIG_PREEMPT_TRACER
43static inline int
44preempt_trace(void)
45{
46 return ((trace_type & TRACER_PREEMPT_OFF) && preempt_count());
47}
48#else
49# define preempt_trace() (0)
50#endif
51
52#ifdef CONFIG_IRQSOFF_TRACER
53static inline int
54irq_trace(void)
55{
56 return ((trace_type & TRACER_IRQS_OFF) &&
57 irqs_disabled());
58}
59#else
60# define irq_trace() (0)
61#endif
62
63#ifdef CONFIG_FUNCTION_GRAPH_TRACER
64static int irqsoff_display_graph(struct trace_array *tr, int set);
65# define is_graph(tr) ((tr)->trace_flags & TRACE_ITER_DISPLAY_GRAPH)
66#else
67static inline int irqsoff_display_graph(struct trace_array *tr, int set)
68{
69 return -EINVAL;
70}
71# define is_graph(tr) false
72#endif
73
74/*
75 * Sequence count - we record it when starting a measurement and
76 * skip the latency if the sequence has changed - some other section
77 * did a maximum and could disturb our measurement with serial console
78 * printouts, etc. Truly coinciding maximum latencies should be rare
79 * and what happens together happens separately as well, so this doesn't
80 * decrease the validity of the maximum found:
81 */
82static __cacheline_aligned_in_smp unsigned long max_sequence;
83
84#ifdef CONFIG_FUNCTION_TRACER
85/*
86 * Prologue for the preempt and irqs off function tracers.
87 *
88 * Returns 1 if it is OK to continue, and data->disabled is
89 * incremented.
90 * 0 if the trace is to be ignored, and data->disabled
91 * is kept the same.
92 *
93 * Note, this function is also used outside this ifdef but
94 * inside the #ifdef of the function graph tracer below.
95 * This is OK, since the function graph tracer is
96 * dependent on the function tracer.
97 */
98static int func_prolog_dec(struct trace_array *tr,
99 struct trace_array_cpu **data,
100 unsigned long *flags)
101{
102 long disabled;
103 int cpu;
104
105 /*
106 * Does not matter if we preempt. We test the flags
107 * afterward, to see if irqs are disabled or not.
108 * If we preempt and get a false positive, the flags
109 * test will fail.
110 */
111 cpu = raw_smp_processor_id();
112 if (likely(!per_cpu(tracing_cpu, cpu)))
113 return 0;
114
115 local_save_flags(*flags);
116 /*
117 * Slight chance to get a false positive on tracing_cpu,
118 * although I'm starting to think there isn't a chance.
119 * Leave this for now just to be paranoid.
120 */
121 if (!irqs_disabled_flags(*flags) && !preempt_count())
122 return 0;
123
124 *data = per_cpu_ptr(tr->trace_buffer.data, cpu);
125 disabled = atomic_inc_return(&(*data)->disabled);
126
127 if (likely(disabled == 1))
128 return 1;
129
130 atomic_dec(&(*data)->disabled);
131
132 return 0;
133}
134
135/*
136 * irqsoff uses its own tracer function to keep the overhead down:
137 */
138static void
139irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip,
140 struct ftrace_ops *op, struct pt_regs *pt_regs)
141{
142 struct trace_array *tr = irqsoff_trace;
143 struct trace_array_cpu *data;
144 unsigned long flags;
145
146 if (!func_prolog_dec(tr, &data, &flags))
147 return;
148
149 trace_function(tr, ip, parent_ip, flags, preempt_count());
150
151 atomic_dec(&data->disabled);
152}
153#endif /* CONFIG_FUNCTION_TRACER */
154
155#ifdef CONFIG_FUNCTION_GRAPH_TRACER
156static int irqsoff_display_graph(struct trace_array *tr, int set)
157{
158 int cpu;
159
160 if (!(is_graph(tr) ^ set))
161 return 0;
162
163 stop_irqsoff_tracer(irqsoff_trace, !set);
164
165 for_each_possible_cpu(cpu)
166 per_cpu(tracing_cpu, cpu) = 0;
167
168 tr->max_latency = 0;
169 tracing_reset_online_cpus(&irqsoff_trace->trace_buffer);
170
171 return start_irqsoff_tracer(irqsoff_trace, set);
172}
173
174static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
175{
176 struct trace_array *tr = irqsoff_trace;
177 struct trace_array_cpu *data;
178 unsigned long flags;
179 int ret;
180 int pc;
181
182 if (ftrace_graph_ignore_func(trace))
183 return 0;
184 /*
185 * Do not trace a function if it's filtered by set_graph_notrace.
186 * Make the index of ret stack negative to indicate that it should
187 * ignore further functions. But it needs its own ret stack entry
188 * to recover the original index in order to continue tracing after
189 * returning from the function.
190 */
191 if (ftrace_graph_notrace_addr(trace->func))
192 return 1;
193
194 if (!func_prolog_dec(tr, &data, &flags))
195 return 0;
196
197 pc = preempt_count();
198 ret = __trace_graph_entry(tr, trace, flags, pc);
199 atomic_dec(&data->disabled);
200
201 return ret;
202}
203
204static void irqsoff_graph_return(struct ftrace_graph_ret *trace)
205{
206 struct trace_array *tr = irqsoff_trace;
207 struct trace_array_cpu *data;
208 unsigned long flags;
209 int pc;
210
211 if (!func_prolog_dec(tr, &data, &flags))
212 return;
213
214 pc = preempt_count();
215 __trace_graph_return(tr, trace, flags, pc);
216 atomic_dec(&data->disabled);
217}
218
219static void irqsoff_trace_open(struct trace_iterator *iter)
220{
221 if (is_graph(iter->tr))
222 graph_trace_open(iter);
223
224}
225
226static void irqsoff_trace_close(struct trace_iterator *iter)
227{
228 if (iter->private)
229 graph_trace_close(iter);
230}
231
232#define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_CPU | \
233 TRACE_GRAPH_PRINT_PROC | \
234 TRACE_GRAPH_PRINT_ABS_TIME | \
235 TRACE_GRAPH_PRINT_DURATION)
236
237static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
238{
239 /*
240 * In graph mode call the graph tracer output function,
241 * otherwise go with the TRACE_FN event handler
242 */
243 if (is_graph(iter->tr))
244 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
245
246 return TRACE_TYPE_UNHANDLED;
247}
248
249static void irqsoff_print_header(struct seq_file *s)
250{
251 struct trace_array *tr = irqsoff_trace;
252
253 if (is_graph(tr))
254 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
255 else
256 trace_default_header(s);
257}
258
259static void
260__trace_function(struct trace_array *tr,
261 unsigned long ip, unsigned long parent_ip,
262 unsigned long flags, int pc)
263{
264 if (is_graph(tr))
265 trace_graph_function(tr, ip, parent_ip, flags, pc);
266 else
267 trace_function(tr, ip, parent_ip, flags, pc);
268}
269
270#else
271#define __trace_function trace_function
272
273#ifdef CONFIG_FUNCTION_TRACER
274static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
275{
276 return -1;
277}
278#endif
279
280static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
281{
282 return TRACE_TYPE_UNHANDLED;
283}
284
285static void irqsoff_trace_open(struct trace_iterator *iter) { }
286static void irqsoff_trace_close(struct trace_iterator *iter) { }
287
288#ifdef CONFIG_FUNCTION_TRACER
289static void irqsoff_graph_return(struct ftrace_graph_ret *trace) { }
290static void irqsoff_print_header(struct seq_file *s)
291{
292 trace_default_header(s);
293}
294#else
295static void irqsoff_print_header(struct seq_file *s)
296{
297 trace_latency_header(s);
298}
299#endif /* CONFIG_FUNCTION_TRACER */
300#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
301
302/*
303 * Should this new latency be reported/recorded?
304 */
305static bool report_latency(struct trace_array *tr, u64 delta)
306{
307 if (tracing_thresh) {
308 if (delta < tracing_thresh)
309 return false;
310 } else {
311 if (delta <= tr->max_latency)
312 return false;
313 }
314 return true;
315}
316
317static void
318check_critical_timing(struct trace_array *tr,
319 struct trace_array_cpu *data,
320 unsigned long parent_ip,
321 int cpu)
322{
323 u64 T0, T1, delta;
324 unsigned long flags;
325 int pc;
326
327 T0 = data->preempt_timestamp;
328 T1 = ftrace_now(cpu);
329 delta = T1-T0;
330
331 local_save_flags(flags);
332
333 pc = preempt_count();
334
335 if (!report_latency(tr, delta))
336 goto out;
337
338 raw_spin_lock_irqsave(&max_trace_lock, flags);
339
340 /* check if we are still the max latency */
341 if (!report_latency(tr, delta))
342 goto out_unlock;
343
344 __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
345 /* Skip 5 functions to get to the irq/preempt enable function */
346 __trace_stack(tr, flags, 5, pc);
347
348 if (data->critical_sequence != max_sequence)
349 goto out_unlock;
350
351 data->critical_end = parent_ip;
352
353 if (likely(!is_tracing_stopped())) {
354 tr->max_latency = delta;
355 update_max_tr_single(tr, current, cpu);
356 }
357
358 max_sequence++;
359
360out_unlock:
361 raw_spin_unlock_irqrestore(&max_trace_lock, flags);
362
363out:
364 data->critical_sequence = max_sequence;
365 data->preempt_timestamp = ftrace_now(cpu);
366 __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
367}
368
369static inline void
370start_critical_timing(unsigned long ip, unsigned long parent_ip)
371{
372 int cpu;
373 struct trace_array *tr = irqsoff_trace;
374 struct trace_array_cpu *data;
375 unsigned long flags;
376
377 if (!tracer_enabled || !tracing_is_enabled())
378 return;
379
380 cpu = raw_smp_processor_id();
381
382 if (per_cpu(tracing_cpu, cpu))
383 return;
384
385 data = per_cpu_ptr(tr->trace_buffer.data, cpu);
386
387 if (unlikely(!data) || atomic_read(&data->disabled))
388 return;
389
390 atomic_inc(&data->disabled);
391
392 data->critical_sequence = max_sequence;
393 data->preempt_timestamp = ftrace_now(cpu);
394 data->critical_start = parent_ip ? : ip;
395
396 local_save_flags(flags);
397
398 __trace_function(tr, ip, parent_ip, flags, preempt_count());
399
400 per_cpu(tracing_cpu, cpu) = 1;
401
402 atomic_dec(&data->disabled);
403}
404
405static inline void
406stop_critical_timing(unsigned long ip, unsigned long parent_ip)
407{
408 int cpu;
409 struct trace_array *tr = irqsoff_trace;
410 struct trace_array_cpu *data;
411 unsigned long flags;
412
413 cpu = raw_smp_processor_id();
414 /* Always clear the tracing cpu on stopping the trace */
415 if (unlikely(per_cpu(tracing_cpu, cpu)))
416 per_cpu(tracing_cpu, cpu) = 0;
417 else
418 return;
419
420 if (!tracer_enabled || !tracing_is_enabled())
421 return;
422
423 data = per_cpu_ptr(tr->trace_buffer.data, cpu);
424
425 if (unlikely(!data) ||
426 !data->critical_start || atomic_read(&data->disabled))
427 return;
428
429 atomic_inc(&data->disabled);
430
431 local_save_flags(flags);
432 __trace_function(tr, ip, parent_ip, flags, preempt_count());
433 check_critical_timing(tr, data, parent_ip ? : ip, cpu);
434 data->critical_start = 0;
435 atomic_dec(&data->disabled);
436}
437
438/* start and stop critical timings used to for stoppage (in idle) */
439void start_critical_timings(void)
440{
441 if (preempt_trace() || irq_trace())
442 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
443}
444EXPORT_SYMBOL_GPL(start_critical_timings);
445
446void stop_critical_timings(void)
447{
448 if (preempt_trace() || irq_trace())
449 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
450}
451EXPORT_SYMBOL_GPL(stop_critical_timings);
452
453#ifdef CONFIG_IRQSOFF_TRACER
454#ifdef CONFIG_PROVE_LOCKING
455void time_hardirqs_on(unsigned long a0, unsigned long a1)
456{
457 if (!preempt_trace() && irq_trace())
458 stop_critical_timing(a0, a1);
459}
460
461void time_hardirqs_off(unsigned long a0, unsigned long a1)
462{
463 if (!preempt_trace() && irq_trace())
464 start_critical_timing(a0, a1);
465}
466
467#else /* !CONFIG_PROVE_LOCKING */
468
469/*
470 * We are only interested in hardirq on/off events:
471 */
472static inline void tracer_hardirqs_on(void)
473{
474 if (!preempt_trace() && irq_trace())
475 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
476}
477
478static inline void tracer_hardirqs_off(void)
479{
480 if (!preempt_trace() && irq_trace())
481 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
482}
483
484static inline void tracer_hardirqs_on_caller(unsigned long caller_addr)
485{
486 if (!preempt_trace() && irq_trace())
487 stop_critical_timing(CALLER_ADDR0, caller_addr);
488}
489
490static inline void tracer_hardirqs_off_caller(unsigned long caller_addr)
491{
492 if (!preempt_trace() && irq_trace())
493 start_critical_timing(CALLER_ADDR0, caller_addr);
494}
495
496#endif /* CONFIG_PROVE_LOCKING */
497#endif /* CONFIG_IRQSOFF_TRACER */
498
499#ifdef CONFIG_PREEMPT_TRACER
500static inline void tracer_preempt_on(unsigned long a0, unsigned long a1)
501{
502 if (preempt_trace() && !irq_trace())
503 stop_critical_timing(a0, a1);
504}
505
506static inline void tracer_preempt_off(unsigned long a0, unsigned long a1)
507{
508 if (preempt_trace() && !irq_trace())
509 start_critical_timing(a0, a1);
510}
511#endif /* CONFIG_PREEMPT_TRACER */
512
513#ifdef CONFIG_FUNCTION_TRACER
514static bool function_enabled;
515
516static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
517{
518 int ret;
519
520 /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
521 if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION)))
522 return 0;
523
524 if (graph)
525 ret = register_ftrace_graph(&irqsoff_graph_return,
526 &irqsoff_graph_entry);
527 else
528 ret = register_ftrace_function(tr->ops);
529
530 if (!ret)
531 function_enabled = true;
532
533 return ret;
534}
535
536static void unregister_irqsoff_function(struct trace_array *tr, int graph)
537{
538 if (!function_enabled)
539 return;
540
541 if (graph)
542 unregister_ftrace_graph();
543 else
544 unregister_ftrace_function(tr->ops);
545
546 function_enabled = false;
547}
548
549static int irqsoff_function_set(struct trace_array *tr, u32 mask, int set)
550{
551 if (!(mask & TRACE_ITER_FUNCTION))
552 return 0;
553
554 if (set)
555 register_irqsoff_function(tr, is_graph(tr), 1);
556 else
557 unregister_irqsoff_function(tr, is_graph(tr));
558 return 1;
559}
560#else
561static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
562{
563 return 0;
564}
565static void unregister_irqsoff_function(struct trace_array *tr, int graph) { }
566static inline int irqsoff_function_set(struct trace_array *tr, u32 mask, int set)
567{
568 return 0;
569}
570#endif /* CONFIG_FUNCTION_TRACER */
571
572static int irqsoff_flag_changed(struct trace_array *tr, u32 mask, int set)
573{
574 struct tracer *tracer = tr->current_trace;
575
576 if (irqsoff_function_set(tr, mask, set))
577 return 0;
578
579#ifdef CONFIG_FUNCTION_GRAPH_TRACER
580 if (mask & TRACE_ITER_DISPLAY_GRAPH)
581 return irqsoff_display_graph(tr, set);
582#endif
583
584 return trace_keep_overwrite(tracer, mask, set);
585}
586
587static int start_irqsoff_tracer(struct trace_array *tr, int graph)
588{
589 int ret;
590
591 ret = register_irqsoff_function(tr, graph, 0);
592
593 if (!ret && tracing_is_enabled())
594 tracer_enabled = 1;
595 else
596 tracer_enabled = 0;
597
598 return ret;
599}
600
601static void stop_irqsoff_tracer(struct trace_array *tr, int graph)
602{
603 tracer_enabled = 0;
604
605 unregister_irqsoff_function(tr, graph);
606}
607
608static bool irqsoff_busy;
609
610static int __irqsoff_tracer_init(struct trace_array *tr)
611{
612 if (irqsoff_busy)
613 return -EBUSY;
614
615 save_flags = tr->trace_flags;
616
617 /* non overwrite screws up the latency tracers */
618 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
619 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
620
621 tr->max_latency = 0;
622 irqsoff_trace = tr;
623 /* make sure that the tracer is visible */
624 smp_wmb();
625
626 ftrace_init_array_ops(tr, irqsoff_tracer_call);
627
628 /* Only toplevel instance supports graph tracing */
629 if (start_irqsoff_tracer(tr, (tr->flags & TRACE_ARRAY_FL_GLOBAL &&
630 is_graph(tr))))
631 printk(KERN_ERR "failed to start irqsoff tracer\n");
632
633 irqsoff_busy = true;
634 return 0;
635}
636
637static void irqsoff_tracer_reset(struct trace_array *tr)
638{
639 int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
640 int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
641
642 stop_irqsoff_tracer(tr, is_graph(tr));
643
644 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
645 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
646 ftrace_reset_array_ops(tr);
647
648 irqsoff_busy = false;
649}
650
651static void irqsoff_tracer_start(struct trace_array *tr)
652{
653 tracer_enabled = 1;
654}
655
656static void irqsoff_tracer_stop(struct trace_array *tr)
657{
658 tracer_enabled = 0;
659}
660
661#ifdef CONFIG_IRQSOFF_TRACER
662static int irqsoff_tracer_init(struct trace_array *tr)
663{
664 trace_type = TRACER_IRQS_OFF;
665
666 return __irqsoff_tracer_init(tr);
667}
668static struct tracer irqsoff_tracer __read_mostly =
669{
670 .name = "irqsoff",
671 .init = irqsoff_tracer_init,
672 .reset = irqsoff_tracer_reset,
673 .start = irqsoff_tracer_start,
674 .stop = irqsoff_tracer_stop,
675 .print_max = true,
676 .print_header = irqsoff_print_header,
677 .print_line = irqsoff_print_line,
678 .flag_changed = irqsoff_flag_changed,
679#ifdef CONFIG_FTRACE_SELFTEST
680 .selftest = trace_selftest_startup_irqsoff,
681#endif
682 .open = irqsoff_trace_open,
683 .close = irqsoff_trace_close,
684 .allow_instances = true,
685 .use_max_tr = true,
686};
687# define register_irqsoff(trace) register_tracer(&trace)
688#else
689# define register_irqsoff(trace) do { } while (0)
690#endif
691
692#ifdef CONFIG_PREEMPT_TRACER
693static int preemptoff_tracer_init(struct trace_array *tr)
694{
695 trace_type = TRACER_PREEMPT_OFF;
696
697 return __irqsoff_tracer_init(tr);
698}
699
700static struct tracer preemptoff_tracer __read_mostly =
701{
702 .name = "preemptoff",
703 .init = preemptoff_tracer_init,
704 .reset = irqsoff_tracer_reset,
705 .start = irqsoff_tracer_start,
706 .stop = irqsoff_tracer_stop,
707 .print_max = true,
708 .print_header = irqsoff_print_header,
709 .print_line = irqsoff_print_line,
710 .flag_changed = irqsoff_flag_changed,
711#ifdef CONFIG_FTRACE_SELFTEST
712 .selftest = trace_selftest_startup_preemptoff,
713#endif
714 .open = irqsoff_trace_open,
715 .close = irqsoff_trace_close,
716 .allow_instances = true,
717 .use_max_tr = true,
718};
719# define register_preemptoff(trace) register_tracer(&trace)
720#else
721# define register_preemptoff(trace) do { } while (0)
722#endif
723
724#if defined(CONFIG_IRQSOFF_TRACER) && \
725 defined(CONFIG_PREEMPT_TRACER)
726
727static int preemptirqsoff_tracer_init(struct trace_array *tr)
728{
729 trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF;
730
731 return __irqsoff_tracer_init(tr);
732}
733
734static struct tracer preemptirqsoff_tracer __read_mostly =
735{
736 .name = "preemptirqsoff",
737 .init = preemptirqsoff_tracer_init,
738 .reset = irqsoff_tracer_reset,
739 .start = irqsoff_tracer_start,
740 .stop = irqsoff_tracer_stop,
741 .print_max = true,
742 .print_header = irqsoff_print_header,
743 .print_line = irqsoff_print_line,
744 .flag_changed = irqsoff_flag_changed,
745#ifdef CONFIG_FTRACE_SELFTEST
746 .selftest = trace_selftest_startup_preemptirqsoff,
747#endif
748 .open = irqsoff_trace_open,
749 .close = irqsoff_trace_close,
750 .allow_instances = true,
751 .use_max_tr = true,
752};
753
754# define register_preemptirqsoff(trace) register_tracer(&trace)
755#else
756# define register_preemptirqsoff(trace) do { } while (0)
757#endif
758
759__init static int init_irqsoff_tracer(void)
760{
761 register_irqsoff(irqsoff_tracer);
762 register_preemptoff(preemptoff_tracer);
763 register_preemptirqsoff(preemptirqsoff_tracer);
764
765 return 0;
766}
767core_initcall(init_irqsoff_tracer);
768#endif /* IRQSOFF_TRACER || PREEMPTOFF_TRACER */
769
770#ifndef CONFIG_IRQSOFF_TRACER
771static inline void tracer_hardirqs_on(void) { }
772static inline void tracer_hardirqs_off(void) { }
773static inline void tracer_hardirqs_on_caller(unsigned long caller_addr) { }
774static inline void tracer_hardirqs_off_caller(unsigned long caller_addr) { }
775#endif
776
777#ifndef CONFIG_PREEMPT_TRACER
778static inline void tracer_preempt_on(unsigned long a0, unsigned long a1) { }
779static inline void tracer_preempt_off(unsigned long a0, unsigned long a1) { }
780#endif
781
782#if defined(CONFIG_TRACE_IRQFLAGS) && !defined(CONFIG_PROVE_LOCKING)
783/* Per-cpu variable to prevent redundant calls when IRQs already off */
784static DEFINE_PER_CPU(int, tracing_irq_cpu);
785
786void trace_hardirqs_on(void)
787{
788 if (!this_cpu_read(tracing_irq_cpu))
789 return;
790
791 trace_irq_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
792 tracer_hardirqs_on();
793
794 this_cpu_write(tracing_irq_cpu, 0);
795}
796EXPORT_SYMBOL(trace_hardirqs_on);
797
798void trace_hardirqs_off(void)
799{
800 if (this_cpu_read(tracing_irq_cpu))
801 return;
802
803 this_cpu_write(tracing_irq_cpu, 1);
804
805 trace_irq_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
806 tracer_hardirqs_off();
807}
808EXPORT_SYMBOL(trace_hardirqs_off);
809
810__visible void trace_hardirqs_on_caller(unsigned long caller_addr)
811{
812 if (!this_cpu_read(tracing_irq_cpu))
813 return;
814
815 trace_irq_enable_rcuidle(CALLER_ADDR0, caller_addr);
816 tracer_hardirqs_on_caller(caller_addr);
817
818 this_cpu_write(tracing_irq_cpu, 0);
819}
820EXPORT_SYMBOL(trace_hardirqs_on_caller);
821
822__visible void trace_hardirqs_off_caller(unsigned long caller_addr)
823{
824 if (this_cpu_read(tracing_irq_cpu))
825 return;
826
827 this_cpu_write(tracing_irq_cpu, 1);
828
829 trace_irq_disable_rcuidle(CALLER_ADDR0, caller_addr);
830 tracer_hardirqs_off_caller(caller_addr);
831}
832EXPORT_SYMBOL(trace_hardirqs_off_caller);
833
834/*
835 * Stubs:
836 */
837
838void trace_softirqs_on(unsigned long ip)
839{
840}
841
842void trace_softirqs_off(unsigned long ip)
843{
844}
845
846inline void print_irqtrace_events(struct task_struct *curr)
847{
848}
849#endif
850
851#if defined(CONFIG_PREEMPT_TRACER) || \
852 (defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_PREEMPTIRQ_EVENTS))
853void trace_preempt_on(unsigned long a0, unsigned long a1)
854{
855 trace_preempt_enable_rcuidle(a0, a1);
856 tracer_preempt_on(a0, a1);
857}
858
859void trace_preempt_off(unsigned long a0, unsigned long a1)
860{
861 trace_preempt_disable_rcuidle(a0, a1);
862 tracer_preempt_off(a0, a1);
863}
864#endif