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12#include <linux/kallsyms.h>
13#include <linux/debugfs.h>
14#include <linux/uaccess.h>
15#include <linux/module.h>
16#include <linux/ftrace.h>
17#include <linux/fs.h>
18
19#include "trace.h"
20
21static struct trace_array *irqsoff_trace __read_mostly;
22static int tracer_enabled __read_mostly;
23
24static DEFINE_PER_CPU(int, tracing_cpu);
25
26static DEFINE_RAW_SPINLOCK(max_trace_lock);
27
28enum {
29 TRACER_IRQS_OFF = (1 << 1),
30 TRACER_PREEMPT_OFF = (1 << 2),
31};
32
33static int trace_type __read_mostly;
34
35static int save_flags;
36
37static void stop_irqsoff_tracer(struct trace_array *tr, int graph);
38static int start_irqsoff_tracer(struct trace_array *tr, int graph);
39
40#ifdef CONFIG_PREEMPT_TRACER
41static inline int
42preempt_trace(void)
43{
44 return ((trace_type & TRACER_PREEMPT_OFF) && preempt_count());
45}
46#else
47# define preempt_trace() (0)
48#endif
49
50#ifdef CONFIG_IRQSOFF_TRACER
51static inline int
52irq_trace(void)
53{
54 return ((trace_type & TRACER_IRQS_OFF) &&
55 irqs_disabled());
56}
57#else
58# define irq_trace() (0)
59#endif
60
61#define TRACE_DISPLAY_GRAPH 1
62
63static struct tracer_opt trace_opts[] = {
64#ifdef CONFIG_FUNCTION_GRAPH_TRACER
65
66 { TRACER_OPT(display-graph, TRACE_DISPLAY_GRAPH) },
67#endif
68 { }
69};
70
71static struct tracer_flags tracer_flags = {
72 .val = 0,
73 .opts = trace_opts,
74};
75
76#define is_graph() (tracer_flags.val & TRACE_DISPLAY_GRAPH)
77
78
79
80
81
82
83
84
85
86static __cacheline_aligned_in_smp unsigned long max_sequence;
87
88#ifdef CONFIG_FUNCTION_TRACER
89
90
91
92
93
94
95
96
97
98
99
100
101
102static int func_prolog_dec(struct trace_array *tr,
103 struct trace_array_cpu **data,
104 unsigned long *flags)
105{
106 long disabled;
107 int cpu;
108
109
110
111
112
113
114
115 cpu = raw_smp_processor_id();
116 if (likely(!per_cpu(tracing_cpu, cpu)))
117 return 0;
118
119 local_save_flags(*flags);
120
121 if (!irqs_disabled_flags(*flags))
122 return 0;
123
124 *data = tr->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
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
154static struct ftrace_ops trace_ops __read_mostly =
155{
156 .func = irqsoff_tracer_call,
157 .flags = FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_RECURSION_SAFE,
158};
159#endif
160
161#ifdef CONFIG_FUNCTION_GRAPH_TRACER
162static int irqsoff_set_flag(u32 old_flags, u32 bit, int set)
163{
164 int cpu;
165
166 if (!(bit & TRACE_DISPLAY_GRAPH))
167 return -EINVAL;
168
169 if (!(is_graph() ^ set))
170 return 0;
171
172 stop_irqsoff_tracer(irqsoff_trace, !set);
173
174 for_each_possible_cpu(cpu)
175 per_cpu(tracing_cpu, cpu) = 0;
176
177 tracing_max_latency = 0;
178 tracing_reset_online_cpus(irqsoff_trace);
179
180 return start_irqsoff_tracer(irqsoff_trace, set);
181}
182
183static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
184{
185 struct trace_array *tr = irqsoff_trace;
186 struct trace_array_cpu *data;
187 unsigned long flags;
188 int ret;
189 int pc;
190
191 if (!func_prolog_dec(tr, &data, &flags))
192 return 0;
193
194 pc = preempt_count();
195 ret = __trace_graph_entry(tr, trace, flags, pc);
196 atomic_dec(&data->disabled);
197
198 return ret;
199}
200
201static void irqsoff_graph_return(struct ftrace_graph_ret *trace)
202{
203 struct trace_array *tr = irqsoff_trace;
204 struct trace_array_cpu *data;
205 unsigned long flags;
206 int pc;
207
208 if (!func_prolog_dec(tr, &data, &flags))
209 return;
210
211 pc = preempt_count();
212 __trace_graph_return(tr, trace, flags, pc);
213 atomic_dec(&data->disabled);
214}
215
216static void irqsoff_trace_open(struct trace_iterator *iter)
217{
218 if (is_graph())
219 graph_trace_open(iter);
220
221}
222
223static void irqsoff_trace_close(struct trace_iterator *iter)
224{
225 if (iter->private)
226 graph_trace_close(iter);
227}
228
229#define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_CPU | \
230 TRACE_GRAPH_PRINT_PROC | \
231 TRACE_GRAPH_PRINT_ABS_TIME | \
232 TRACE_GRAPH_PRINT_DURATION)
233
234static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
235{
236
237
238
239
240 if (is_graph())
241 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
242
243 return TRACE_TYPE_UNHANDLED;
244}
245
246static void irqsoff_print_header(struct seq_file *s)
247{
248 if (is_graph())
249 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
250 else
251 trace_default_header(s);
252}
253
254static void
255__trace_function(struct trace_array *tr,
256 unsigned long ip, unsigned long parent_ip,
257 unsigned long flags, int pc)
258{
259 if (is_graph())
260 trace_graph_function(tr, ip, parent_ip, flags, pc);
261 else
262 trace_function(tr, ip, parent_ip, flags, pc);
263}
264
265#else
266#define __trace_function trace_function
267
268static int irqsoff_set_flag(u32 old_flags, u32 bit, int set)
269{
270 return -EINVAL;
271}
272
273static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
274{
275 return -1;
276}
277
278static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
279{
280 return TRACE_TYPE_UNHANDLED;
281}
282
283static void irqsoff_graph_return(struct ftrace_graph_ret *trace) { }
284static void irqsoff_trace_open(struct trace_iterator *iter) { }
285static void irqsoff_trace_close(struct trace_iterator *iter) { }
286
287#ifdef CONFIG_FUNCTION_TRACER
288static void irqsoff_print_header(struct seq_file *s)
289{
290 trace_default_header(s);
291}
292#else
293static void irqsoff_print_header(struct seq_file *s)
294{
295 trace_latency_header(s);
296}
297#endif
298#endif
299
300
301
302
303static int report_latency(cycle_t delta)
304{
305 if (tracing_thresh) {
306 if (delta < tracing_thresh)
307 return 0;
308 } else {
309 if (delta <= tracing_max_latency)
310 return 0;
311 }
312 return 1;
313}
314
315static void
316check_critical_timing(struct trace_array *tr,
317 struct trace_array_cpu *data,
318 unsigned long parent_ip,
319 int cpu)
320{
321 cycle_t T0, T1, delta;
322 unsigned long flags;
323 int pc;
324
325 T0 = data->preempt_timestamp;
326 T1 = ftrace_now(cpu);
327 delta = T1-T0;
328
329 local_save_flags(flags);
330
331 pc = preempt_count();
332
333 if (!report_latency(delta))
334 goto out;
335
336 raw_spin_lock_irqsave(&max_trace_lock, flags);
337
338
339 if (!report_latency(delta))
340 goto out_unlock;
341
342 __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
343
344 __trace_stack(tr, flags, 5, pc);
345
346 if (data->critical_sequence != max_sequence)
347 goto out_unlock;
348
349 data->critical_end = parent_ip;
350
351 if (likely(!is_tracing_stopped())) {
352 tracing_max_latency = delta;
353 update_max_tr_single(tr, current, cpu);
354 }
355
356 max_sequence++;
357
358out_unlock:
359 raw_spin_unlock_irqrestore(&max_trace_lock, flags);
360
361out:
362 data->critical_sequence = max_sequence;
363 data->preempt_timestamp = ftrace_now(cpu);
364 __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
365}
366
367static inline void
368start_critical_timing(unsigned long ip, unsigned long parent_ip)
369{
370 int cpu;
371 struct trace_array *tr = irqsoff_trace;
372 struct trace_array_cpu *data;
373 unsigned long flags;
374
375 if (likely(!tracer_enabled))
376 return;
377
378 cpu = raw_smp_processor_id();
379
380 if (per_cpu(tracing_cpu, cpu))
381 return;
382
383 data = tr->data[cpu];
384
385 if (unlikely(!data) || atomic_read(&data->disabled))
386 return;
387
388 atomic_inc(&data->disabled);
389
390 data->critical_sequence = max_sequence;
391 data->preempt_timestamp = ftrace_now(cpu);
392 data->critical_start = parent_ip ? : ip;
393
394 local_save_flags(flags);
395
396 __trace_function(tr, ip, parent_ip, flags, preempt_count());
397
398 per_cpu(tracing_cpu, cpu) = 1;
399
400 atomic_dec(&data->disabled);
401}
402
403static 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 long flags;
410
411 cpu = raw_smp_processor_id();
412
413 if (unlikely(per_cpu(tracing_cpu, cpu)))
414 per_cpu(tracing_cpu, cpu) = 0;
415 else
416 return;
417
418 if (!tracer_enabled)
419 return;
420
421 data = tr->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 local_save_flags(flags);
430 __trace_function(tr, ip, parent_ip, flags, preempt_count());
431 check_critical_timing(tr, data, parent_ip ? : ip, cpu);
432 data->critical_start = 0;
433 atomic_dec(&data->disabled);
434}
435
436
437void start_critical_timings(void)
438{
439 if (preempt_trace() || irq_trace())
440 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
441}
442EXPORT_SYMBOL_GPL(start_critical_timings);
443
444void stop_critical_timings(void)
445{
446 if (preempt_trace() || irq_trace())
447 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
448}
449EXPORT_SYMBOL_GPL(stop_critical_timings);
450
451#ifdef CONFIG_IRQSOFF_TRACER
452#ifdef CONFIG_PROVE_LOCKING
453void time_hardirqs_on(unsigned long a0, unsigned long a1)
454{
455 if (!preempt_trace() && irq_trace())
456 stop_critical_timing(a0, a1);
457}
458
459void time_hardirqs_off(unsigned long a0, unsigned long a1)
460{
461 if (!preempt_trace() && irq_trace())
462 start_critical_timing(a0, a1);
463}
464
465#else
466
467
468
469
470
471void trace_softirqs_on(unsigned long ip)
472{
473}
474
475void trace_softirqs_off(unsigned long ip)
476{
477}
478
479inline void print_irqtrace_events(struct task_struct *curr)
480{
481}
482
483
484
485
486void trace_hardirqs_on(void)
487{
488 if (!preempt_trace() && irq_trace())
489 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
490}
491EXPORT_SYMBOL(trace_hardirqs_on);
492
493void trace_hardirqs_off(void)
494{
495 if (!preempt_trace() && irq_trace())
496 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
497}
498EXPORT_SYMBOL(trace_hardirqs_off);
499
500void trace_hardirqs_on_caller(unsigned long caller_addr)
501{
502 if (!preempt_trace() && irq_trace())
503 stop_critical_timing(CALLER_ADDR0, caller_addr);
504}
505EXPORT_SYMBOL(trace_hardirqs_on_caller);
506
507void trace_hardirqs_off_caller(unsigned long caller_addr)
508{
509 if (!preempt_trace() && irq_trace())
510 start_critical_timing(CALLER_ADDR0, caller_addr);
511}
512EXPORT_SYMBOL(trace_hardirqs_off_caller);
513
514#endif
515#endif
516
517#ifdef CONFIG_PREEMPT_TRACER
518void trace_preempt_on(unsigned long a0, unsigned long a1)
519{
520 if (preempt_trace() && !irq_trace())
521 stop_critical_timing(a0, a1);
522}
523
524void trace_preempt_off(unsigned long a0, unsigned long a1)
525{
526 if (preempt_trace() && !irq_trace())
527 start_critical_timing(a0, a1);
528}
529#endif
530
531static int start_irqsoff_tracer(struct trace_array *tr, int graph)
532{
533 int ret = 0;
534
535 if (!graph)
536 ret = register_ftrace_function(&trace_ops);
537 else
538 ret = register_ftrace_graph(&irqsoff_graph_return,
539 &irqsoff_graph_entry);
540
541 if (!ret && tracing_is_enabled())
542 tracer_enabled = 1;
543 else
544 tracer_enabled = 0;
545
546 return ret;
547}
548
549static void stop_irqsoff_tracer(struct trace_array *tr, int graph)
550{
551 tracer_enabled = 0;
552
553 if (!graph)
554 unregister_ftrace_function(&trace_ops);
555 else
556 unregister_ftrace_graph();
557}
558
559static void __irqsoff_tracer_init(struct trace_array *tr)
560{
561 save_flags = trace_flags;
562
563
564 set_tracer_flag(TRACE_ITER_OVERWRITE, 1);
565 set_tracer_flag(TRACE_ITER_LATENCY_FMT, 1);
566
567 tracing_max_latency = 0;
568 irqsoff_trace = tr;
569
570 smp_wmb();
571 tracing_reset_online_cpus(tr);
572
573 if (start_irqsoff_tracer(tr, is_graph()))
574 printk(KERN_ERR "failed to start irqsoff tracer\n");
575}
576
577static void irqsoff_tracer_reset(struct trace_array *tr)
578{
579 int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
580 int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
581
582 stop_irqsoff_tracer(tr, is_graph());
583
584 set_tracer_flag(TRACE_ITER_LATENCY_FMT, lat_flag);
585 set_tracer_flag(TRACE_ITER_OVERWRITE, overwrite_flag);
586}
587
588static void irqsoff_tracer_start(struct trace_array *tr)
589{
590 tracer_enabled = 1;
591}
592
593static void irqsoff_tracer_stop(struct trace_array *tr)
594{
595 tracer_enabled = 0;
596}
597
598#ifdef CONFIG_IRQSOFF_TRACER
599static int irqsoff_tracer_init(struct trace_array *tr)
600{
601 trace_type = TRACER_IRQS_OFF;
602
603 __irqsoff_tracer_init(tr);
604 return 0;
605}
606static struct tracer irqsoff_tracer __read_mostly =
607{
608 .name = "irqsoff",
609 .init = irqsoff_tracer_init,
610 .reset = irqsoff_tracer_reset,
611 .start = irqsoff_tracer_start,
612 .stop = irqsoff_tracer_stop,
613 .print_max = true,
614 .print_header = irqsoff_print_header,
615 .print_line = irqsoff_print_line,
616 .flags = &tracer_flags,
617 .set_flag = irqsoff_set_flag,
618 .flag_changed = trace_keep_overwrite,
619#ifdef CONFIG_FTRACE_SELFTEST
620 .selftest = trace_selftest_startup_irqsoff,
621#endif
622 .open = irqsoff_trace_open,
623 .close = irqsoff_trace_close,
624 .use_max_tr = true,
625};
626# define register_irqsoff(trace) register_tracer(&trace)
627#else
628# define register_irqsoff(trace) do { } while (0)
629#endif
630
631#ifdef CONFIG_PREEMPT_TRACER
632static int preemptoff_tracer_init(struct trace_array *tr)
633{
634 trace_type = TRACER_PREEMPT_OFF;
635
636 __irqsoff_tracer_init(tr);
637 return 0;
638}
639
640static struct tracer preemptoff_tracer __read_mostly =
641{
642 .name = "preemptoff",
643 .init = preemptoff_tracer_init,
644 .reset = irqsoff_tracer_reset,
645 .start = irqsoff_tracer_start,
646 .stop = irqsoff_tracer_stop,
647 .print_max = true,
648 .print_header = irqsoff_print_header,
649 .print_line = irqsoff_print_line,
650 .flags = &tracer_flags,
651 .set_flag = irqsoff_set_flag,
652 .flag_changed = trace_keep_overwrite,
653#ifdef CONFIG_FTRACE_SELFTEST
654 .selftest = trace_selftest_startup_preemptoff,
655#endif
656 .open = irqsoff_trace_open,
657 .close = irqsoff_trace_close,
658 .use_max_tr = true,
659};
660# define register_preemptoff(trace) register_tracer(&trace)
661#else
662# define register_preemptoff(trace) do { } while (0)
663#endif
664
665#if defined(CONFIG_IRQSOFF_TRACER) && \
666 defined(CONFIG_PREEMPT_TRACER)
667
668static int preemptirqsoff_tracer_init(struct trace_array *tr)
669{
670 trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF;
671
672 __irqsoff_tracer_init(tr);
673 return 0;
674}
675
676static struct tracer preemptirqsoff_tracer __read_mostly =
677{
678 .name = "preemptirqsoff",
679 .init = preemptirqsoff_tracer_init,
680 .reset = irqsoff_tracer_reset,
681 .start = irqsoff_tracer_start,
682 .stop = irqsoff_tracer_stop,
683 .print_max = true,
684 .print_header = irqsoff_print_header,
685 .print_line = irqsoff_print_line,
686 .flags = &tracer_flags,
687 .set_flag = irqsoff_set_flag,
688 .flag_changed = trace_keep_overwrite,
689#ifdef CONFIG_FTRACE_SELFTEST
690 .selftest = trace_selftest_startup_preemptirqsoff,
691#endif
692 .open = irqsoff_trace_open,
693 .close = irqsoff_trace_close,
694 .use_max_tr = true,
695};
696
697# define register_preemptirqsoff(trace) register_tracer(&trace)
698#else
699# define register_preemptirqsoff(trace) do { } while (0)
700#endif
701
702__init static int init_irqsoff_tracer(void)
703{
704 register_irqsoff(irqsoff_tracer);
705 register_preemptoff(preemptoff_tracer);
706 register_preemptirqsoff(preemptirqsoff_tracer);
707
708 return 0;
709}
710core_initcall(init_irqsoff_tracer);
711