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Linux 3.7.1
[linux/fpc-iii.git] / kernel / trace / trace_functions_graph.c
blob99b4378393d5fae8ea1c8de91032129f52a45216
1 /*
2 *
3 * Function graph tracer.
4 * Copyright (c) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com>
5 * Mostly borrowed from function tracer which
6 * is Copyright (c) Steven Rostedt <srostedt@redhat.com>
7 *
8 */
9 #include <linux/debugfs.h>
10 #include <linux/uaccess.h>
11 #include <linux/ftrace.h>
12 #include <linux/slab.h>
13 #include <linux/fs.h>
14
15 #include "trace.h"
16 #include "trace_output.h"
17
18 /* When set, irq functions will be ignored */
19 static int ftrace_graph_skip_irqs;
20
21 struct fgraph_cpu_data {
22 pid_t last_pid;
23 int depth;
24 int depth_irq;
25 int ignore;
26 unsigned long enter_funcs[FTRACE_RETFUNC_DEPTH];
27 };
28
29 struct fgraph_data {
30 struct fgraph_cpu_data __percpu *cpu_data;
31
32 /* Place to preserve last processed entry. */
33 struct ftrace_graph_ent_entry ent;
34 struct ftrace_graph_ret_entry ret;
35 int failed;
36 int cpu;
37 };
38
39 #define TRACE_GRAPH_INDENT 2
40
41 /* Flag options */
42 #define TRACE_GRAPH_PRINT_OVERRUN 0x1
43 #define TRACE_GRAPH_PRINT_CPU 0x2
44 #define TRACE_GRAPH_PRINT_OVERHEAD 0x4
45 #define TRACE_GRAPH_PRINT_PROC 0x8
46 #define TRACE_GRAPH_PRINT_DURATION 0x10
47 #define TRACE_GRAPH_PRINT_ABS_TIME 0x20
48 #define TRACE_GRAPH_PRINT_IRQS 0x40
49
50 static struct tracer_opt trace_opts[] = {
51 /* Display overruns? (for self-debug purpose) */
52 { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
53 /* Display CPU ? */
54 { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
55 /* Display Overhead ? */
56 { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
57 /* Display proc name/pid */
58 { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
59 /* Display duration of execution */
60 { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
61 /* Display absolute time of an entry */
62 { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
63 /* Display interrupts */
64 { TRACER_OPT(funcgraph-irqs, TRACE_GRAPH_PRINT_IRQS) },
65 { } /* Empty entry */
66 };
67
68 static struct tracer_flags tracer_flags = {
69 /* Don't display overruns and proc by default */
70 .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
71 TRACE_GRAPH_PRINT_DURATION | TRACE_GRAPH_PRINT_IRQS,
72 .opts = trace_opts
73 };
74
75 static struct trace_array *graph_array;
76
77 /*
78 * DURATION column is being also used to display IRQ signs,
79 * following values are used by print_graph_irq and others
80 * to fill in space into DURATION column.
81 */
82 enum {
83 DURATION_FILL_FULL = -1,
84 DURATION_FILL_START = -2,
85 DURATION_FILL_END = -3,
86 };
87
88 static enum print_line_t
89 print_graph_duration(unsigned long long duration, struct trace_seq *s,
90 u32 flags);
91
92 /* Add a function return address to the trace stack on thread info.*/
93 int
94 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
95 unsigned long frame_pointer)
96 {
97 unsigned long long calltime;
98 int index;
99
100 if (!current->ret_stack)
101 return -EBUSY;
102
103 /*
104 * We must make sure the ret_stack is tested before we read
105 * anything else.
106 */
107 smp_rmb();
108
109 /* The return trace stack is full */
110 if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
111 atomic_inc(&current->trace_overrun);
112 return -EBUSY;
113 }
114
115 calltime = trace_clock_local();
116
117 index = ++current->curr_ret_stack;
118 barrier();
119 current->ret_stack[index].ret = ret;
120 current->ret_stack[index].func = func;
121 current->ret_stack[index].calltime = calltime;
122 current->ret_stack[index].subtime = 0;
123 current->ret_stack[index].fp = frame_pointer;
124 *depth = index;
125
126 return 0;
127 }
128
129 /* Retrieve a function return address to the trace stack on thread info.*/
130 static void
131 ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
132 unsigned long frame_pointer)
133 {
134 int index;
135
136 index = current->curr_ret_stack;
137
138 if (unlikely(index < 0)) {
139 ftrace_graph_stop();
140 WARN_ON(1);
141 /* Might as well panic, otherwise we have no where to go */
142 *ret = (unsigned long)panic;
143 return;
144 }
145
146 #if defined(CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST) && !defined(CC_USING_FENTRY)
147 /*
148 * The arch may choose to record the frame pointer used
149 * and check it here to make sure that it is what we expect it
150 * to be. If gcc does not set the place holder of the return
151 * address in the frame pointer, and does a copy instead, then
152 * the function graph trace will fail. This test detects this
153 * case.
154 *
155 * Currently, x86_32 with optimize for size (-Os) makes the latest
156 * gcc do the above.
157 *
158 * Note, -mfentry does not use frame pointers, and this test
159 * is not needed if CC_USING_FENTRY is set.
160 */
161 if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
162 ftrace_graph_stop();
163 WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
164 " from func %ps return to %lx\n",
165 current->ret_stack[index].fp,
166 frame_pointer,
167 (void *)current->ret_stack[index].func,
168 current->ret_stack[index].ret);
169 *ret = (unsigned long)panic;
170 return;
171 }
172 #endif
173
174 *ret = current->ret_stack[index].ret;
175 trace->func = current->ret_stack[index].func;
176 trace->calltime = current->ret_stack[index].calltime;
177 trace->overrun = atomic_read(&current->trace_overrun);
178 trace->depth = index;
179 }
180
181 /*
182 * Send the trace to the ring-buffer.
183 * @return the original return address.
184 */
185 unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
186 {
187 struct ftrace_graph_ret trace;
188 unsigned long ret;
189
190 ftrace_pop_return_trace(&trace, &ret, frame_pointer);
191 trace.rettime = trace_clock_local();
192 ftrace_graph_return(&trace);
193 barrier();
194 current->curr_ret_stack--;
195
196 if (unlikely(!ret)) {
197 ftrace_graph_stop();
198 WARN_ON(1);
199 /* Might as well panic. What else to do? */
200 ret = (unsigned long)panic;
201 }
202
203 return ret;
204 }
205
206 int __trace_graph_entry(struct trace_array *tr,
207 struct ftrace_graph_ent *trace,
208 unsigned long flags,
209 int pc)
210 {
211 struct ftrace_event_call *call = &event_funcgraph_entry;
212 struct ring_buffer_event *event;
213 struct ring_buffer *buffer = tr->buffer;
214 struct ftrace_graph_ent_entry *entry;
215
216 if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
217 return 0;
218
219 event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
220 sizeof(*entry), flags, pc);
221 if (!event)
222 return 0;
223 entry = ring_buffer_event_data(event);
224 entry->graph_ent = *trace;
225 if (!filter_current_check_discard(buffer, call, entry, event))
226 ring_buffer_unlock_commit(buffer, event);
227
228 return 1;
229 }
230
231 static inline int ftrace_graph_ignore_irqs(void)
232 {
233 if (!ftrace_graph_skip_irqs || trace_recursion_test(TRACE_IRQ_BIT))
234 return 0;
235
236 return in_irq();
237 }
238
239 int trace_graph_entry(struct ftrace_graph_ent *trace)
240 {
241 struct trace_array *tr = graph_array;
242 struct trace_array_cpu *data;
243 unsigned long flags;
244 long disabled;
245 int ret;
246 int cpu;
247 int pc;
248
249 if (!ftrace_trace_task(current))
250 return 0;
251
252 /* trace it when it is-nested-in or is a function enabled. */
253 if (!(trace->depth || ftrace_graph_addr(trace->func)) ||
254 ftrace_graph_ignore_irqs())
255 return 0;
256
257 local_irq_save(flags);
258 cpu = raw_smp_processor_id();
259 data = tr->data[cpu];
260 disabled = atomic_inc_return(&data->disabled);
261 if (likely(disabled == 1)) {
262 pc = preempt_count();
263 ret = __trace_graph_entry(tr, trace, flags, pc);
264 } else {
265 ret = 0;
266 }
267
268 atomic_dec(&data->disabled);
269 local_irq_restore(flags);
270
271 return ret;
272 }
273
274 int trace_graph_thresh_entry(struct ftrace_graph_ent *trace)
275 {
276 if (tracing_thresh)
277 return 1;
278 else
279 return trace_graph_entry(trace);
280 }
281
282 static void
283 __trace_graph_function(struct trace_array *tr,
284 unsigned long ip, unsigned long flags, int pc)
285 {
286 u64 time = trace_clock_local();
287 struct ftrace_graph_ent ent = {
288 .func = ip,
289 .depth = 0,
290 };
291 struct ftrace_graph_ret ret = {
292 .func = ip,
293 .depth = 0,
294 .calltime = time,
295 .rettime = time,
296 };
297
298 __trace_graph_entry(tr, &ent, flags, pc);
299 __trace_graph_return(tr, &ret, flags, pc);
300 }
301
302 void
303 trace_graph_function(struct trace_array *tr,
304 unsigned long ip, unsigned long parent_ip,
305 unsigned long flags, int pc)
306 {
307 __trace_graph_function(tr, ip, flags, pc);
308 }
309
310 void __trace_graph_return(struct trace_array *tr,
311 struct ftrace_graph_ret *trace,
312 unsigned long flags,
313 int pc)
314 {
315 struct ftrace_event_call *call = &event_funcgraph_exit;
316 struct ring_buffer_event *event;
317 struct ring_buffer *buffer = tr->buffer;
318 struct ftrace_graph_ret_entry *entry;
319
320 if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
321 return;
322
323 event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
324 sizeof(*entry), flags, pc);
325 if (!event)
326 return;
327 entry = ring_buffer_event_data(event);
328 entry->ret = *trace;
329 if (!filter_current_check_discard(buffer, call, entry, event))
330 ring_buffer_unlock_commit(buffer, event);
331 }
332
333 void trace_graph_return(struct ftrace_graph_ret *trace)
334 {
335 struct trace_array *tr = graph_array;
336 struct trace_array_cpu *data;
337 unsigned long flags;
338 long disabled;
339 int cpu;
340 int pc;
341
342 local_irq_save(flags);
343 cpu = raw_smp_processor_id();
344 data = tr->data[cpu];
345 disabled = atomic_inc_return(&data->disabled);
346 if (likely(disabled == 1)) {
347 pc = preempt_count();
348 __trace_graph_return(tr, trace, flags, pc);
349 }
350 atomic_dec(&data->disabled);
351 local_irq_restore(flags);
352 }
353
354 void set_graph_array(struct trace_array *tr)
355 {
356 graph_array = tr;
357
358 /* Make graph_array visible before we start tracing */
359
360 smp_mb();
361 }
362
363 void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
364 {
365 if (tracing_thresh &&
366 (trace->rettime - trace->calltime < tracing_thresh))
367 return;
368 else
369 trace_graph_return(trace);
370 }
371
372 static int graph_trace_init(struct trace_array *tr)
373 {
374 int ret;
375
376 set_graph_array(tr);
377 if (tracing_thresh)
378 ret = register_ftrace_graph(&trace_graph_thresh_return,
379 &trace_graph_thresh_entry);
380 else
381 ret = register_ftrace_graph(&trace_graph_return,
382 &trace_graph_entry);
383 if (ret)
384 return ret;
385 tracing_start_cmdline_record();
386
387 return 0;
388 }
389
390 static void graph_trace_reset(struct trace_array *tr)
391 {
392 tracing_stop_cmdline_record();
393 unregister_ftrace_graph();
394 }
395
396 static int max_bytes_for_cpu;
397
398 static enum print_line_t
399 print_graph_cpu(struct trace_seq *s, int cpu)
400 {
401 int ret;
402
403 /*
404 * Start with a space character - to make it stand out
405 * to the right a bit when trace output is pasted into
406 * email:
407 */
408 ret = trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
409 if (!ret)
410 return TRACE_TYPE_PARTIAL_LINE;
411
412 return TRACE_TYPE_HANDLED;
413 }
414
415 #define TRACE_GRAPH_PROCINFO_LENGTH 14
416
417 static enum print_line_t
418 print_graph_proc(struct trace_seq *s, pid_t pid)
419 {
420 char comm[TASK_COMM_LEN];
421 /* sign + log10(MAX_INT) + '\0' */
422 char pid_str[11];
423 int spaces = 0;
424 int ret;
425 int len;
426 int i;
427
428 trace_find_cmdline(pid, comm);
429 comm[7] = '\0';
430 sprintf(pid_str, "%d", pid);
431
432 /* 1 stands for the "-" character */
433 len = strlen(comm) + strlen(pid_str) + 1;
434
435 if (len < TRACE_GRAPH_PROCINFO_LENGTH)
436 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
437
438 /* First spaces to align center */
439 for (i = 0; i < spaces / 2; i++) {
440 ret = trace_seq_printf(s, " ");
441 if (!ret)
442 return TRACE_TYPE_PARTIAL_LINE;
443 }
444
445 ret = trace_seq_printf(s, "%s-%s", comm, pid_str);
446 if (!ret)
447 return TRACE_TYPE_PARTIAL_LINE;
448
449 /* Last spaces to align center */
450 for (i = 0; i < spaces - (spaces / 2); i++) {
451 ret = trace_seq_printf(s, " ");
452 if (!ret)
453 return TRACE_TYPE_PARTIAL_LINE;
454 }
455 return TRACE_TYPE_HANDLED;
456 }
457
458
459 static enum print_line_t
460 print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
461 {
462 if (!trace_seq_putc(s, ' '))
463 return 0;
464
465 return trace_print_lat_fmt(s, entry);
466 }
467
468 /* If the pid changed since the last trace, output this event */
469 static enum print_line_t
470 verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
471 {
472 pid_t prev_pid;
473 pid_t *last_pid;
474 int ret;
475
476 if (!data)
477 return TRACE_TYPE_HANDLED;
478
479 last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
480
481 if (*last_pid == pid)
482 return TRACE_TYPE_HANDLED;
483
484 prev_pid = *last_pid;
485 *last_pid = pid;
486
487 if (prev_pid == -1)
488 return TRACE_TYPE_HANDLED;
489 /*
490 * Context-switch trace line:
491
492 ------------------------------------------
493 | 1) migration/0--1 => sshd-1755
494 ------------------------------------------
495
496 */
497 ret = trace_seq_printf(s,
498 " ------------------------------------------\n");
499 if (!ret)
500 return TRACE_TYPE_PARTIAL_LINE;
501
502 ret = print_graph_cpu(s, cpu);
503 if (ret == TRACE_TYPE_PARTIAL_LINE)
504 return TRACE_TYPE_PARTIAL_LINE;
505
506 ret = print_graph_proc(s, prev_pid);
507 if (ret == TRACE_TYPE_PARTIAL_LINE)
508 return TRACE_TYPE_PARTIAL_LINE;
509
510 ret = trace_seq_printf(s, " => ");
511 if (!ret)
512 return TRACE_TYPE_PARTIAL_LINE;
513
514 ret = print_graph_proc(s, pid);
515 if (ret == TRACE_TYPE_PARTIAL_LINE)
516 return TRACE_TYPE_PARTIAL_LINE;
517
518 ret = trace_seq_printf(s,
519 "\n ------------------------------------------\n\n");
520 if (!ret)
521 return TRACE_TYPE_PARTIAL_LINE;
522
523 return TRACE_TYPE_HANDLED;
524 }
525
526 static struct ftrace_graph_ret_entry *
527 get_return_for_leaf(struct trace_iterator *iter,
528 struct ftrace_graph_ent_entry *curr)
529 {
530 struct fgraph_data *data = iter->private;
531 struct ring_buffer_iter *ring_iter = NULL;
532 struct ring_buffer_event *event;
533 struct ftrace_graph_ret_entry *next;
534
535 /*
536 * If the previous output failed to write to the seq buffer,
537 * then we just reuse the data from before.
538 */
539 if (data && data->failed) {
540 curr = &data->ent;
541 next = &data->ret;
542 } else {
543
544 ring_iter = trace_buffer_iter(iter, iter->cpu);
545
546 /* First peek to compare current entry and the next one */
547 if (ring_iter)
548 event = ring_buffer_iter_peek(ring_iter, NULL);
549 else {
550 /*
551 * We need to consume the current entry to see
552 * the next one.
553 */
554 ring_buffer_consume(iter->tr->buffer, iter->cpu,
555 NULL, NULL);
556 event = ring_buffer_peek(iter->tr->buffer, iter->cpu,
557 NULL, NULL);
558 }
559
560 if (!event)
561 return NULL;
562
563 next = ring_buffer_event_data(event);
564
565 if (data) {
566 /*
567 * Save current and next entries for later reference
568 * if the output fails.
569 */
570 data->ent = *curr;
571 /*
572 * If the next event is not a return type, then
573 * we only care about what type it is. Otherwise we can
574 * safely copy the entire event.
575 */
576 if (next->ent.type == TRACE_GRAPH_RET)
577 data->ret = *next;
578 else
579 data->ret.ent.type = next->ent.type;
580 }
581 }
582
583 if (next->ent.type != TRACE_GRAPH_RET)
584 return NULL;
585
586 if (curr->ent.pid != next->ent.pid ||
587 curr->graph_ent.func != next->ret.func)
588 return NULL;
589
590 /* this is a leaf, now advance the iterator */
591 if (ring_iter)
592 ring_buffer_read(ring_iter, NULL);
593
594 return next;
595 }
596
597 static int print_graph_abs_time(u64 t, struct trace_seq *s)
598 {
599 unsigned long usecs_rem;
600
601 usecs_rem = do_div(t, NSEC_PER_SEC);
602 usecs_rem /= 1000;
603
604 return trace_seq_printf(s, "%5lu.%06lu | ",
605 (unsigned long)t, usecs_rem);
606 }
607
608 static enum print_line_t
609 print_graph_irq(struct trace_iterator *iter, unsigned long addr,
610 enum trace_type type, int cpu, pid_t pid, u32 flags)
611 {
612 int ret;
613 struct trace_seq *s = &iter->seq;
614
615 if (addr < (unsigned long)__irqentry_text_start ||
616 addr >= (unsigned long)__irqentry_text_end)
617 return TRACE_TYPE_UNHANDLED;
618
619 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
620 /* Absolute time */
621 if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {
622 ret = print_graph_abs_time(iter->ts, s);
623 if (!ret)
624 return TRACE_TYPE_PARTIAL_LINE;
625 }
626
627 /* Cpu */
628 if (flags & TRACE_GRAPH_PRINT_CPU) {
629 ret = print_graph_cpu(s, cpu);
630 if (ret == TRACE_TYPE_PARTIAL_LINE)
631 return TRACE_TYPE_PARTIAL_LINE;
632 }
633
634 /* Proc */
635 if (flags & TRACE_GRAPH_PRINT_PROC) {
636 ret = print_graph_proc(s, pid);
637 if (ret == TRACE_TYPE_PARTIAL_LINE)
638 return TRACE_TYPE_PARTIAL_LINE;
639 ret = trace_seq_printf(s, " | ");
640 if (!ret)
641 return TRACE_TYPE_PARTIAL_LINE;
642 }
643 }
644
645 /* No overhead */
646 ret = print_graph_duration(DURATION_FILL_START, s, flags);
647 if (ret != TRACE_TYPE_HANDLED)
648 return ret;
649
650 if (type == TRACE_GRAPH_ENT)
651 ret = trace_seq_printf(s, "==========>");
652 else
653 ret = trace_seq_printf(s, "<==========");
654
655 if (!ret)
656 return TRACE_TYPE_PARTIAL_LINE;
657
658 ret = print_graph_duration(DURATION_FILL_END, s, flags);
659 if (ret != TRACE_TYPE_HANDLED)
660 return ret;
661
662 ret = trace_seq_printf(s, "\n");
663
664 if (!ret)
665 return TRACE_TYPE_PARTIAL_LINE;
666 return TRACE_TYPE_HANDLED;
667 }
668
669 enum print_line_t
670 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
671 {
672 unsigned long nsecs_rem = do_div(duration, 1000);
673 /* log10(ULONG_MAX) + '\0' */
674 char msecs_str[21];
675 char nsecs_str[5];
676 int ret, len;
677 int i;
678
679 sprintf(msecs_str, "%lu", (unsigned long) duration);
680
681 /* Print msecs */
682 ret = trace_seq_printf(s, "%s", msecs_str);
683 if (!ret)
684 return TRACE_TYPE_PARTIAL_LINE;
685
686 len = strlen(msecs_str);
687
688 /* Print nsecs (we don't want to exceed 7 numbers) */
689 if (len < 7) {
690 size_t slen = min_t(size_t, sizeof(nsecs_str), 8UL - len);
691
692 snprintf(nsecs_str, slen, "%03lu", nsecs_rem);
693 ret = trace_seq_printf(s, ".%s", nsecs_str);
694 if (!ret)
695 return TRACE_TYPE_PARTIAL_LINE;
696 len += strlen(nsecs_str);
697 }
698
699 ret = trace_seq_printf(s, " us ");
700 if (!ret)
701 return TRACE_TYPE_PARTIAL_LINE;
702
703 /* Print remaining spaces to fit the row's width */
704 for (i = len; i < 7; i++) {
705 ret = trace_seq_printf(s, " ");
706 if (!ret)
707 return TRACE_TYPE_PARTIAL_LINE;
708 }
709 return TRACE_TYPE_HANDLED;
710 }
711
712 static enum print_line_t
713 print_graph_duration(unsigned long long duration, struct trace_seq *s,
714 u32 flags)
715 {
716 int ret = -1;
717
718 if (!(flags & TRACE_GRAPH_PRINT_DURATION) ||
719 !(trace_flags & TRACE_ITER_CONTEXT_INFO))
720 return TRACE_TYPE_HANDLED;
721
722 /* No real adata, just filling the column with spaces */
723 switch (duration) {
724 case DURATION_FILL_FULL:
725 ret = trace_seq_printf(s, " | ");
726 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
727 case DURATION_FILL_START:
728 ret = trace_seq_printf(s, " ");
729 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
730 case DURATION_FILL_END:
731 ret = trace_seq_printf(s, " |");
732 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
733 }
734
735 /* Signal a overhead of time execution to the output */
736 if (flags & TRACE_GRAPH_PRINT_OVERHEAD) {
737 /* Duration exceeded 100 msecs */
738 if (duration > 100000ULL)
739 ret = trace_seq_printf(s, "! ");
740 /* Duration exceeded 10 msecs */
741 else if (duration > 10000ULL)
742 ret = trace_seq_printf(s, "+ ");
743 }
744
745 /*
746 * The -1 means we either did not exceed the duration tresholds
747 * or we dont want to print out the overhead. Either way we need
748 * to fill out the space.
749 */
750 if (ret == -1)
751 ret = trace_seq_printf(s, " ");
752
753 /* Catching here any failure happenned above */
754 if (!ret)
755 return TRACE_TYPE_PARTIAL_LINE;
756
757 ret = trace_print_graph_duration(duration, s);
758 if (ret != TRACE_TYPE_HANDLED)
759 return ret;
760
761 ret = trace_seq_printf(s, "| ");
762 if (!ret)
763 return TRACE_TYPE_PARTIAL_LINE;
764
765 return TRACE_TYPE_HANDLED;
766 }
767
768 /* Case of a leaf function on its call entry */
769 static enum print_line_t
770 print_graph_entry_leaf(struct trace_iterator *iter,
771 struct ftrace_graph_ent_entry *entry,
772 struct ftrace_graph_ret_entry *ret_entry,
773 struct trace_seq *s, u32 flags)
774 {
775 struct fgraph_data *data = iter->private;
776 struct ftrace_graph_ret *graph_ret;
777 struct ftrace_graph_ent *call;
778 unsigned long long duration;
779 int ret;
780 int i;
781
782 graph_ret = &ret_entry->ret;
783 call = &entry->graph_ent;
784 duration = graph_ret->rettime - graph_ret->calltime;
785
786 if (data) {
787 struct fgraph_cpu_data *cpu_data;
788 int cpu = iter->cpu;
789
790 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
791
792 /*
793 * Comments display at + 1 to depth. Since
794 * this is a leaf function, keep the comments
795 * equal to this depth.
796 */
797 cpu_data->depth = call->depth - 1;
798
799 /* No need to keep this function around for this depth */
800 if (call->depth < FTRACE_RETFUNC_DEPTH)
801 cpu_data->enter_funcs[call->depth] = 0;
802 }
803
804 /* Overhead and duration */
805 ret = print_graph_duration(duration, s, flags);
806 if (ret == TRACE_TYPE_PARTIAL_LINE)
807 return TRACE_TYPE_PARTIAL_LINE;
808
809 /* Function */
810 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
811 ret = trace_seq_printf(s, " ");
812 if (!ret)
813 return TRACE_TYPE_PARTIAL_LINE;
814 }
815
816 ret = trace_seq_printf(s, "%ps();\n", (void *)call->func);
817 if (!ret)
818 return TRACE_TYPE_PARTIAL_LINE;
819
820 return TRACE_TYPE_HANDLED;
821 }
822
823 static enum print_line_t
824 print_graph_entry_nested(struct trace_iterator *iter,
825 struct ftrace_graph_ent_entry *entry,
826 struct trace_seq *s, int cpu, u32 flags)
827 {
828 struct ftrace_graph_ent *call = &entry->graph_ent;
829 struct fgraph_data *data = iter->private;
830 int ret;
831 int i;
832
833 if (data) {
834 struct fgraph_cpu_data *cpu_data;
835 int cpu = iter->cpu;
836
837 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
838 cpu_data->depth = call->depth;
839
840 /* Save this function pointer to see if the exit matches */
841 if (call->depth < FTRACE_RETFUNC_DEPTH)
842 cpu_data->enter_funcs[call->depth] = call->func;
843 }
844
845 /* No time */
846 ret = print_graph_duration(DURATION_FILL_FULL, s, flags);
847 if (ret != TRACE_TYPE_HANDLED)
848 return ret;
849
850 /* Function */
851 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
852 ret = trace_seq_printf(s, " ");
853 if (!ret)
854 return TRACE_TYPE_PARTIAL_LINE;
855 }
856
857 ret = trace_seq_printf(s, "%ps() {\n", (void *)call->func);
858 if (!ret)
859 return TRACE_TYPE_PARTIAL_LINE;
860
861 /*
862 * we already consumed the current entry to check the next one
863 * and see if this is a leaf.
864 */
865 return TRACE_TYPE_NO_CONSUME;
866 }
867
868 static enum print_line_t
869 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
870 int type, unsigned long addr, u32 flags)
871 {
872 struct fgraph_data *data = iter->private;
873 struct trace_entry *ent = iter->ent;
874 int cpu = iter->cpu;
875 int ret;
876
877 /* Pid */
878 if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)
879 return TRACE_TYPE_PARTIAL_LINE;
880
881 if (type) {
882 /* Interrupt */
883 ret = print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
884 if (ret == TRACE_TYPE_PARTIAL_LINE)
885 return TRACE_TYPE_PARTIAL_LINE;
886 }
887
888 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
889 return 0;
890
891 /* Absolute time */
892 if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {
893 ret = print_graph_abs_time(iter->ts, s);
894 if (!ret)
895 return TRACE_TYPE_PARTIAL_LINE;
896 }
897
898 /* Cpu */
899 if (flags & TRACE_GRAPH_PRINT_CPU) {
900 ret = print_graph_cpu(s, cpu);
901 if (ret == TRACE_TYPE_PARTIAL_LINE)
902 return TRACE_TYPE_PARTIAL_LINE;
903 }
904
905 /* Proc */
906 if (flags & TRACE_GRAPH_PRINT_PROC) {
907 ret = print_graph_proc(s, ent->pid);
908 if (ret == TRACE_TYPE_PARTIAL_LINE)
909 return TRACE_TYPE_PARTIAL_LINE;
910
911 ret = trace_seq_printf(s, " | ");
912 if (!ret)
913 return TRACE_TYPE_PARTIAL_LINE;
914 }
915
916 /* Latency format */
917 if (trace_flags & TRACE_ITER_LATENCY_FMT) {
918 ret = print_graph_lat_fmt(s, ent);
919 if (ret == TRACE_TYPE_PARTIAL_LINE)
920 return TRACE_TYPE_PARTIAL_LINE;
921 }
922
923 return 0;
924 }
925
926 /*
927 * Entry check for irq code
928 *
929 * returns 1 if
930 * - we are inside irq code
931 * - we just entered irq code
932 *
933 * retunns 0 if
934 * - funcgraph-interrupts option is set
935 * - we are not inside irq code
936 */
937 static int
938 check_irq_entry(struct trace_iterator *iter, u32 flags,
939 unsigned long addr, int depth)
940 {
941 int cpu = iter->cpu;
942 int *depth_irq;
943 struct fgraph_data *data = iter->private;
944
945 /*
946 * If we are either displaying irqs, or we got called as
947 * a graph event and private data does not exist,
948 * then we bypass the irq check.
949 */
950 if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
951 (!data))
952 return 0;
953
954 depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
955
956 /*
957 * We are inside the irq code
958 */
959 if (*depth_irq >= 0)
960 return 1;
961
962 if ((addr < (unsigned long)__irqentry_text_start) ||
963 (addr >= (unsigned long)__irqentry_text_end))
964 return 0;
965
966 /*
967 * We are entering irq code.
968 */
969 *depth_irq = depth;
970 return 1;
971 }
972
973 /*
974 * Return check for irq code
975 *
976 * returns 1 if
977 * - we are inside irq code
978 * - we just left irq code
979 *
980 * returns 0 if
981 * - funcgraph-interrupts option is set
982 * - we are not inside irq code
983 */
984 static int
985 check_irq_return(struct trace_iterator *iter, u32 flags, int depth)
986 {
987 int cpu = iter->cpu;
988 int *depth_irq;
989 struct fgraph_data *data = iter->private;
990
991 /*
992 * If we are either displaying irqs, or we got called as
993 * a graph event and private data does not exist,
994 * then we bypass the irq check.
995 */
996 if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
997 (!data))
998 return 0;
999
1000 depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1001
1002 /*
1003 * We are not inside the irq code.
1004 */
1005 if (*depth_irq == -1)
1006 return 0;
1007
1008 /*
1009 * We are inside the irq code, and this is returning entry.
1010 * Let's not trace it and clear the entry depth, since
1011 * we are out of irq code.
1012 *
1013 * This condition ensures that we 'leave the irq code' once
1014 * we are out of the entry depth. Thus protecting us from
1015 * the RETURN entry loss.
1016 */
1017 if (*depth_irq >= depth) {
1018 *depth_irq = -1;
1019 return 1;
1020 }
1021
1022 /*
1023 * We are inside the irq code, and this is not the entry.
1024 */
1025 return 1;
1026 }
1027
1028 static enum print_line_t
1029 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
1030 struct trace_iterator *iter, u32 flags)
1031 {
1032 struct fgraph_data *data = iter->private;
1033 struct ftrace_graph_ent *call = &field->graph_ent;
1034 struct ftrace_graph_ret_entry *leaf_ret;
1035 static enum print_line_t ret;
1036 int cpu = iter->cpu;
1037
1038 if (check_irq_entry(iter, flags, call->func, call->depth))
1039 return TRACE_TYPE_HANDLED;
1040
1041 if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags))
1042 return TRACE_TYPE_PARTIAL_LINE;
1043
1044 leaf_ret = get_return_for_leaf(iter, field);
1045 if (leaf_ret)
1046 ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags);
1047 else
1048 ret = print_graph_entry_nested(iter, field, s, cpu, flags);
1049
1050 if (data) {
1051 /*
1052 * If we failed to write our output, then we need to make
1053 * note of it. Because we already consumed our entry.
1054 */
1055 if (s->full) {
1056 data->failed = 1;
1057 data->cpu = cpu;
1058 } else
1059 data->failed = 0;
1060 }
1061
1062 return ret;
1063 }
1064
1065 static enum print_line_t
1066 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
1067 struct trace_entry *ent, struct trace_iterator *iter,
1068 u32 flags)
1069 {
1070 unsigned long long duration = trace->rettime - trace->calltime;
1071 struct fgraph_data *data = iter->private;
1072 pid_t pid = ent->pid;
1073 int cpu = iter->cpu;
1074 int func_match = 1;
1075 int ret;
1076 int i;
1077
1078 if (check_irq_return(iter, flags, trace->depth))
1079 return TRACE_TYPE_HANDLED;
1080
1081 if (data) {
1082 struct fgraph_cpu_data *cpu_data;
1083 int cpu = iter->cpu;
1084
1085 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
1086
1087 /*
1088 * Comments display at + 1 to depth. This is the
1089 * return from a function, we now want the comments
1090 * to display at the same level of the bracket.
1091 */
1092 cpu_data->depth = trace->depth - 1;
1093
1094 if (trace->depth < FTRACE_RETFUNC_DEPTH) {
1095 if (cpu_data->enter_funcs[trace->depth] != trace->func)
1096 func_match = 0;
1097 cpu_data->enter_funcs[trace->depth] = 0;
1098 }
1099 }
1100
1101 if (print_graph_prologue(iter, s, 0, 0, flags))
1102 return TRACE_TYPE_PARTIAL_LINE;
1103
1104 /* Overhead and duration */
1105 ret = print_graph_duration(duration, s, flags);
1106 if (ret == TRACE_TYPE_PARTIAL_LINE)
1107 return TRACE_TYPE_PARTIAL_LINE;
1108
1109 /* Closing brace */
1110 for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
1111 ret = trace_seq_printf(s, " ");
1112 if (!ret)
1113 return TRACE_TYPE_PARTIAL_LINE;
1114 }
1115
1116 /*
1117 * If the return function does not have a matching entry,
1118 * then the entry was lost. Instead of just printing
1119 * the '}' and letting the user guess what function this
1120 * belongs to, write out the function name.
1121 */
1122 if (func_match) {
1123 ret = trace_seq_printf(s, "}\n");
1124 if (!ret)
1125 return TRACE_TYPE_PARTIAL_LINE;
1126 } else {
1127 ret = trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
1128 if (!ret)
1129 return TRACE_TYPE_PARTIAL_LINE;
1130 }
1131
1132 /* Overrun */
1133 if (flags & TRACE_GRAPH_PRINT_OVERRUN) {
1134 ret = trace_seq_printf(s, " (Overruns: %lu)\n",
1135 trace->overrun);
1136 if (!ret)
1137 return TRACE_TYPE_PARTIAL_LINE;
1138 }
1139
1140 ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
1141 cpu, pid, flags);
1142 if (ret == TRACE_TYPE_PARTIAL_LINE)
1143 return TRACE_TYPE_PARTIAL_LINE;
1144
1145 return TRACE_TYPE_HANDLED;
1146 }
1147
1148 static enum print_line_t
1149 print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
1150 struct trace_iterator *iter, u32 flags)
1151 {
1152 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1153 struct fgraph_data *data = iter->private;
1154 struct trace_event *event;
1155 int depth = 0;
1156 int ret;
1157 int i;
1158
1159 if (data)
1160 depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
1161
1162 if (print_graph_prologue(iter, s, 0, 0, flags))
1163 return TRACE_TYPE_PARTIAL_LINE;
1164
1165 /* No time */
1166 ret = print_graph_duration(DURATION_FILL_FULL, s, flags);
1167 if (ret != TRACE_TYPE_HANDLED)
1168 return ret;
1169
1170 /* Indentation */
1171 if (depth > 0)
1172 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) {
1173 ret = trace_seq_printf(s, " ");
1174 if (!ret)
1175 return TRACE_TYPE_PARTIAL_LINE;
1176 }
1177
1178 /* The comment */
1179 ret = trace_seq_printf(s, "/* ");
1180 if (!ret)
1181 return TRACE_TYPE_PARTIAL_LINE;
1182
1183 switch (iter->ent->type) {
1184 case TRACE_BPRINT:
1185 ret = trace_print_bprintk_msg_only(iter);
1186 if (ret != TRACE_TYPE_HANDLED)
1187 return ret;
1188 break;
1189 case TRACE_PRINT:
1190 ret = trace_print_printk_msg_only(iter);
1191 if (ret != TRACE_TYPE_HANDLED)
1192 return ret;
1193 break;
1194 default:
1195 event = ftrace_find_event(ent->type);
1196 if (!event)
1197 return TRACE_TYPE_UNHANDLED;
1198
1199 ret = event->funcs->trace(iter, sym_flags, event);
1200 if (ret != TRACE_TYPE_HANDLED)
1201 return ret;
1202 }
1203
1204 /* Strip ending newline */
1205 if (s->buffer[s->len - 1] == '\n') {
1206 s->buffer[s->len - 1] = '\0';
1207 s->len--;
1208 }
1209
1210 ret = trace_seq_printf(s, " */\n");
1211 if (!ret)
1212 return TRACE_TYPE_PARTIAL_LINE;
1213
1214 return TRACE_TYPE_HANDLED;
1215 }
1216
1217
1218 enum print_line_t
1219 print_graph_function_flags(struct trace_iterator *iter, u32 flags)
1220 {
1221 struct ftrace_graph_ent_entry *field;
1222 struct fgraph_data *data = iter->private;
1223 struct trace_entry *entry = iter->ent;
1224 struct trace_seq *s = &iter->seq;
1225 int cpu = iter->cpu;
1226 int ret;
1227
1228 if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
1229 per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
1230 return TRACE_TYPE_HANDLED;
1231 }
1232
1233 /*
1234 * If the last output failed, there's a possibility we need
1235 * to print out the missing entry which would never go out.
1236 */
1237 if (data && data->failed) {
1238 field = &data->ent;
1239 iter->cpu = data->cpu;
1240 ret = print_graph_entry(field, s, iter, flags);
1241 if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
1242 per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
1243 ret = TRACE_TYPE_NO_CONSUME;
1244 }
1245 iter->cpu = cpu;
1246 return ret;
1247 }
1248
1249 switch (entry->type) {
1250 case TRACE_GRAPH_ENT: {
1251 /*
1252 * print_graph_entry() may consume the current event,
1253 * thus @field may become invalid, so we need to save it.
1254 * sizeof(struct ftrace_graph_ent_entry) is very small,
1255 * it can be safely saved at the stack.
1256 */
1257 struct ftrace_graph_ent_entry saved;
1258 trace_assign_type(field, entry);
1259 saved = *field;
1260 return print_graph_entry(&saved, s, iter, flags);
1261 }
1262 case TRACE_GRAPH_RET: {
1263 struct ftrace_graph_ret_entry *field;
1264 trace_assign_type(field, entry);
1265 return print_graph_return(&field->ret, s, entry, iter, flags);
1266 }
1267 case TRACE_STACK:
1268 case TRACE_FN:
1269 /* dont trace stack and functions as comments */
1270 return TRACE_TYPE_UNHANDLED;
1271
1272 default:
1273 return print_graph_comment(s, entry, iter, flags);
1274 }
1275
1276 return TRACE_TYPE_HANDLED;
1277 }
1278
1279 static enum print_line_t
1280 print_graph_function(struct trace_iterator *iter)
1281 {
1282 return print_graph_function_flags(iter, tracer_flags.val);
1283 }
1284
1285 static enum print_line_t
1286 print_graph_function_event(struct trace_iterator *iter, int flags,
1287 struct trace_event *event)
1288 {
1289 return print_graph_function(iter);
1290 }
1291
1292 static void print_lat_header(struct seq_file *s, u32 flags)
1293 {
1294 static const char spaces[] = " " /* 16 spaces */
1295 " " /* 4 spaces */
1296 " "; /* 17 spaces */
1297 int size = 0;
1298
1299 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1300 size += 16;
1301 if (flags & TRACE_GRAPH_PRINT_CPU)
1302 size += 4;
1303 if (flags & TRACE_GRAPH_PRINT_PROC)
1304 size += 17;
1305
1306 seq_printf(s, "#%.*s _-----=> irqs-off \n", size, spaces);
1307 seq_printf(s, "#%.*s / _----=> need-resched \n", size, spaces);
1308 seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
1309 seq_printf(s, "#%.*s|| / _--=> preempt-depth \n", size, spaces);
1310 seq_printf(s, "#%.*s||| / \n", size, spaces);
1311 }
1312
1313 static void __print_graph_headers_flags(struct seq_file *s, u32 flags)
1314 {
1315 int lat = trace_flags & TRACE_ITER_LATENCY_FMT;
1316
1317 if (lat)
1318 print_lat_header(s, flags);
1319
1320 /* 1st line */
1321 seq_printf(s, "#");
1322 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1323 seq_printf(s, " TIME ");
1324 if (flags & TRACE_GRAPH_PRINT_CPU)
1325 seq_printf(s, " CPU");
1326 if (flags & TRACE_GRAPH_PRINT_PROC)
1327 seq_printf(s, " TASK/PID ");
1328 if (lat)
1329 seq_printf(s, "||||");
1330 if (flags & TRACE_GRAPH_PRINT_DURATION)
1331 seq_printf(s, " DURATION ");
1332 seq_printf(s, " FUNCTION CALLS\n");
1333
1334 /* 2nd line */
1335 seq_printf(s, "#");
1336 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1337 seq_printf(s, " | ");
1338 if (flags & TRACE_GRAPH_PRINT_CPU)
1339 seq_printf(s, " | ");
1340 if (flags & TRACE_GRAPH_PRINT_PROC)
1341 seq_printf(s, " | | ");
1342 if (lat)
1343 seq_printf(s, "||||");
1344 if (flags & TRACE_GRAPH_PRINT_DURATION)
1345 seq_printf(s, " | | ");
1346 seq_printf(s, " | | | |\n");
1347 }
1348
1349 void print_graph_headers(struct seq_file *s)
1350 {
1351 print_graph_headers_flags(s, tracer_flags.val);
1352 }
1353
1354 void print_graph_headers_flags(struct seq_file *s, u32 flags)
1355 {
1356 struct trace_iterator *iter = s->private;
1357
1358 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
1359 return;
1360
1361 if (trace_flags & TRACE_ITER_LATENCY_FMT) {
1362 /* print nothing if the buffers are empty */
1363 if (trace_empty(iter))
1364 return;
1365
1366 print_trace_header(s, iter);
1367 }
1368
1369 __print_graph_headers_flags(s, flags);
1370 }
1371
1372 void graph_trace_open(struct trace_iterator *iter)
1373 {
1374 /* pid and depth on the last trace processed */
1375 struct fgraph_data *data;
1376 int cpu;
1377
1378 iter->private = NULL;
1379
1380 data = kzalloc(sizeof(*data), GFP_KERNEL);
1381 if (!data)
1382 goto out_err;
1383
1384 data->cpu_data = alloc_percpu(struct fgraph_cpu_data);
1385 if (!data->cpu_data)
1386 goto out_err_free;
1387
1388 for_each_possible_cpu(cpu) {
1389 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
1390 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
1391 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
1392 int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1393
1394 *pid = -1;
1395 *depth = 0;
1396 *ignore = 0;
1397 *depth_irq = -1;
1398 }
1399
1400 iter->private = data;
1401
1402 return;
1403
1404 out_err_free:
1405 kfree(data);
1406 out_err:
1407 pr_warning("function graph tracer: not enough memory\n");
1408 }
1409
1410 void graph_trace_close(struct trace_iterator *iter)
1411 {
1412 struct fgraph_data *data = iter->private;
1413
1414 if (data) {
1415 free_percpu(data->cpu_data);
1416 kfree(data);
1417 }
1418 }
1419
1420 static int func_graph_set_flag(u32 old_flags, u32 bit, int set)
1421 {
1422 if (bit == TRACE_GRAPH_PRINT_IRQS)
1423 ftrace_graph_skip_irqs = !set;
1424
1425 return 0;
1426 }
1427
1428 static struct trace_event_functions graph_functions = {
1429 .trace = print_graph_function_event,
1430 };
1431
1432 static struct trace_event graph_trace_entry_event = {
1433 .type = TRACE_GRAPH_ENT,
1434 .funcs = &graph_functions,
1435 };
1436
1437 static struct trace_event graph_trace_ret_event = {
1438 .type = TRACE_GRAPH_RET,
1439 .funcs = &graph_functions
1440 };
1441
1442 static struct tracer graph_trace __read_mostly = {
1443 .name = "function_graph",
1444 .open = graph_trace_open,
1445 .pipe_open = graph_trace_open,
1446 .close = graph_trace_close,
1447 .pipe_close = graph_trace_close,
1448 .wait_pipe = poll_wait_pipe,
1449 .init = graph_trace_init,
1450 .reset = graph_trace_reset,
1451 .print_line = print_graph_function,
1452 .print_header = print_graph_headers,
1453 .flags = &tracer_flags,
1454 .set_flag = func_graph_set_flag,
1455 #ifdef CONFIG_FTRACE_SELFTEST
1456 .selftest = trace_selftest_startup_function_graph,
1457 #endif
1458 };
1459
1460 static __init int init_graph_trace(void)
1461 {
1462 max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);
1463
1464 if (!register_ftrace_event(&graph_trace_entry_event)) {
1465 pr_warning("Warning: could not register graph trace events\n");
1466 return 1;
1467 }
1468
1469 if (!register_ftrace_event(&graph_trace_ret_event)) {
1470 pr_warning("Warning: could not register graph trace events\n");
1471 return 1;
1472 }
1473
1474 return register_tracer(&graph_trace);
1475 }
1476
1477 device_initcall(init_graph_trace);
Linux with added FPC-III support