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