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/fs.h>
13
14 #include "trace.h"
15 #include "trace_output.h"
16
17 struct fgraph_data {
18 pid_t last_pid;
19 int depth;
20 };
21
22 #define TRACE_GRAPH_INDENT 2
23
24 /* Flag options */
25 #define TRACE_GRAPH_PRINT_OVERRUN 0x1
26 #define TRACE_GRAPH_PRINT_CPU 0x2
27 #define TRACE_GRAPH_PRINT_OVERHEAD 0x4
28 #define TRACE_GRAPH_PRINT_PROC 0x8
29 #define TRACE_GRAPH_PRINT_DURATION 0x10
30 #define TRACE_GRAPH_PRINT_ABS_TIME 0X20
31
32 static struct tracer_opt trace_opts[] = {
33 /* Display overruns? (for self-debug purpose) */
34 { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
35 /* Display CPU ? */
36 { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
37 /* Display Overhead ? */
38 { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
39 /* Display proc name/pid */
40 { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
41 /* Display duration of execution */
42 { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
43 /* Display absolute time of an entry */
44 { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
45 { } /* Empty entry */
46 };
47
48 static struct tracer_flags tracer_flags = {
49 /* Don't display overruns and proc by default */
50 .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
51 TRACE_GRAPH_PRINT_DURATION,
52 .opts = trace_opts
53 };
54
55 /* pid on the last trace processed */
56
57
58 /* Add a function return address to the trace stack on thread info.*/
59 int
60 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
61 unsigned long frame_pointer)
62 {
63 unsigned long long calltime;
64 int index;
65
66 if (!current->ret_stack)
67 return -EBUSY;
68
69 /*
70 * We must make sure the ret_stack is tested before we read
71 * anything else.
72 */
73 smp_rmb();
74
75 /* The return trace stack is full */
76 if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
77 atomic_inc(¤t->trace_overrun);
78 return -EBUSY;
79 }
80
81 calltime = trace_clock_local();
82
83 index = ++current->curr_ret_stack;
84 barrier();
85 current->ret_stack[index].ret = ret;
86 current->ret_stack[index].func = func;
87 current->ret_stack[index].calltime = calltime;
88 current->ret_stack[index].subtime = 0;
89 current->ret_stack[index].fp = frame_pointer;
90 *depth = index;
91
92 return 0;
93 }
94
95 /* Retrieve a function return address to the trace stack on thread info.*/
96 static void
97 ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
98 unsigned long frame_pointer)
99 {
100 int index;
101
102 index = current->curr_ret_stack;
103
104 if (unlikely(index < 0)) {
105 ftrace_graph_stop();
106 WARN_ON(1);
107 /* Might as well panic, otherwise we have no where to go */
108 *ret = (unsigned long)panic;
109 return;
110 }
111
112 #ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST
113 /*
114 * The arch may choose to record the frame pointer used
115 * and check it here to make sure that it is what we expect it
116 * to be. If gcc does not set the place holder of the return
117 * address in the frame pointer, and does a copy instead, then
118 * the function graph trace will fail. This test detects this
119 * case.
120 *
121 * Currently, x86_32 with optimize for size (-Os) makes the latest
122 * gcc do the above.
123 */
124 if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
125 ftrace_graph_stop();
126 WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
127 " from func %pF return to %lx\n",
128 current->ret_stack[index].fp,
129 frame_pointer,
130 (void *)current->ret_stack[index].func,
131 current->ret_stack[index].ret);
132 *ret = (unsigned long)panic;
133 return;
134 }
135 #endif
136
137 *ret = current->ret_stack[index].ret;
138 trace->func = current->ret_stack[index].func;
139 trace->calltime = current->ret_stack[index].calltime;
140 trace->overrun = atomic_read(¤t->trace_overrun);
141 trace->depth = index;
142 }
143
144 /*
145 * Send the trace to the ring-buffer.
146 * @return the original return address.
147 */
148 unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
149 {
150 struct ftrace_graph_ret trace;
151 unsigned long ret;
152
153 ftrace_pop_return_trace(&trace, &ret, frame_pointer);
154 trace.rettime = trace_clock_local();
155 ftrace_graph_return(&trace);
156 barrier();
157 current->curr_ret_stack--;
158
159 if (unlikely(!ret)) {
160 ftrace_graph_stop();
161 WARN_ON(1);
162 /* Might as well panic. What else to do? */
163 ret = (unsigned long)panic;
164 }
165
166 return ret;
167 }
168
169 static int graph_trace_init(struct trace_array *tr)
170 {
171 int ret = register_ftrace_graph(&trace_graph_return,
172 &trace_graph_entry);
173 if (ret)
174 return ret;
175 tracing_start_cmdline_record();
176
177 return 0;
178 }
179
180 static void graph_trace_reset(struct trace_array *tr)
181 {
182 tracing_stop_cmdline_record();
183 unregister_ftrace_graph();
184 }
185
186 static inline int log10_cpu(int nb)
187 {
188 if (nb / 100)
189 return 3;
190 if (nb / 10)
191 return 2;
192 return 1;
193 }
194
195 static enum print_line_t
196 print_graph_cpu(struct trace_seq *s, int cpu)
197 {
198 int i;
199 int ret;
200 int log10_this = log10_cpu(cpu);
201 int log10_all = log10_cpu(cpumask_weight(cpu_online_mask));
202
203
204 /*
205 * Start with a space character - to make it stand out
206 * to the right a bit when trace output is pasted into
207 * email:
208 */
209 ret = trace_seq_printf(s, " ");
210
211 /*
212 * Tricky - we space the CPU field according to the max
213 * number of online CPUs. On a 2-cpu system it would take
214 * a maximum of 1 digit - on a 128 cpu system it would
215 * take up to 3 digits:
216 */
217 for (i = 0; i < log10_all - log10_this; i++) {
218 ret = trace_seq_printf(s, " ");
219 if (!ret)
220 return TRACE_TYPE_PARTIAL_LINE;
221 }
222 ret = trace_seq_printf(s, "%d) ", cpu);
223 if (!ret)
224 return TRACE_TYPE_PARTIAL_LINE;
225
226 return TRACE_TYPE_HANDLED;
227 }
228
229 #define TRACE_GRAPH_PROCINFO_LENGTH 14
230
231 static enum print_line_t
232 print_graph_proc(struct trace_seq *s, pid_t pid)
233 {
234 char comm[TASK_COMM_LEN];
235 /* sign + log10(MAX_INT) + '\0' */
236 char pid_str[11];
237 int spaces = 0;
238 int ret;
239 int len;
240 int i;
241
242 trace_find_cmdline(pid, comm);
243 comm[7] = '\0';
244 sprintf(pid_str, "%d", pid);
245
246 /* 1 stands for the "-" character */
247 len = strlen(comm) + strlen(pid_str) + 1;
248
249 if (len < TRACE_GRAPH_PROCINFO_LENGTH)
250 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
251
252 /* First spaces to align center */
253 for (i = 0; i < spaces / 2; i++) {
254 ret = trace_seq_printf(s, " ");
255 if (!ret)
256 return TRACE_TYPE_PARTIAL_LINE;
257 }
258
259 ret = trace_seq_printf(s, "%s-%s", comm, pid_str);
260 if (!ret)
261 return TRACE_TYPE_PARTIAL_LINE;
262
263 /* Last spaces to align center */
264 for (i = 0; i < spaces - (spaces / 2); i++) {
265 ret = trace_seq_printf(s, " ");
266 if (!ret)
267 return TRACE_TYPE_PARTIAL_LINE;
268 }
269 return TRACE_TYPE_HANDLED;
270 }
271
272
273 /* If the pid changed since the last trace, output this event */
274 static enum print_line_t
275 verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
276 {
277 pid_t prev_pid;
278 pid_t *last_pid;
279 int ret;
280
281 if (!data)
282 return TRACE_TYPE_HANDLED;
283
284 last_pid = &(per_cpu_ptr(data, cpu)->last_pid);
285
286 if (*last_pid == pid)
287 return TRACE_TYPE_HANDLED;
288
289 prev_pid = *last_pid;
290 *last_pid = pid;
291
292 if (prev_pid == -1)
293 return TRACE_TYPE_HANDLED;
294 /*
295 * Context-switch trace line:
296
297 ------------------------------------------
298 | 1) migration/0--1 => sshd-1755
299 ------------------------------------------
300
301 */
302 ret = trace_seq_printf(s,
303 " ------------------------------------------\n");
304 if (!ret)
305 return TRACE_TYPE_PARTIAL_LINE;
306
307 ret = print_graph_cpu(s, cpu);
308 if (ret == TRACE_TYPE_PARTIAL_LINE)
309 return TRACE_TYPE_PARTIAL_LINE;
310
311 ret = print_graph_proc(s, prev_pid);
312 if (ret == TRACE_TYPE_PARTIAL_LINE)
313 return TRACE_TYPE_PARTIAL_LINE;
314
315 ret = trace_seq_printf(s, " => ");
316 if (!ret)
317 return TRACE_TYPE_PARTIAL_LINE;
318
319 ret = print_graph_proc(s, pid);
320 if (ret == TRACE_TYPE_PARTIAL_LINE)
321 return TRACE_TYPE_PARTIAL_LINE;
322
323 ret = trace_seq_printf(s,
324 "\n ------------------------------------------\n\n");
325 if (!ret)
326 return TRACE_TYPE_PARTIAL_LINE;
327
328 return TRACE_TYPE_HANDLED;
329 }
330
331 static struct ftrace_graph_ret_entry *
332 get_return_for_leaf(struct trace_iterator *iter,
333 struct ftrace_graph_ent_entry *curr)
334 {
335 struct ring_buffer_iter *ring_iter;
336 struct ring_buffer_event *event;
337 struct ftrace_graph_ret_entry *next;
338
339 ring_iter = iter->buffer_iter[iter->cpu];
340
341 /* First peek to compare current entry and the next one */
342 if (ring_iter)
343 event = ring_buffer_iter_peek(ring_iter, NULL);
344 else {
345 /* We need to consume the current entry to see the next one */
346 ring_buffer_consume(iter->tr->buffer, iter->cpu, NULL);
347 event = ring_buffer_peek(iter->tr->buffer, iter->cpu,
348 NULL);
349 }
350
351 if (!event)
352 return NULL;
353
354 next = ring_buffer_event_data(event);
355
356 if (next->ent.type != TRACE_GRAPH_RET)
357 return NULL;
358
359 if (curr->ent.pid != next->ent.pid ||
360 curr->graph_ent.func != next->ret.func)
361 return NULL;
362
363 /* this is a leaf, now advance the iterator */
364 if (ring_iter)
365 ring_buffer_read(ring_iter, NULL);
366
367 return next;
368 }
369
370 /* Signal a overhead of time execution to the output */
371 static int
372 print_graph_overhead(unsigned long long duration, struct trace_seq *s)
373 {
374 /* If duration disappear, we don't need anything */
375 if (!(tracer_flags.val & TRACE_GRAPH_PRINT_DURATION))
376 return 1;
377
378 /* Non nested entry or return */
379 if (duration == -1)
380 return trace_seq_printf(s, " ");
381
382 if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
383 /* Duration exceeded 100 msecs */
384 if (duration > 100000ULL)
385 return trace_seq_printf(s, "! ");
386
387 /* Duration exceeded 10 msecs */
388 if (duration > 10000ULL)
389 return trace_seq_printf(s, "+ ");
390 }
391
392 return trace_seq_printf(s, " ");
393 }
394
395 static int print_graph_abs_time(u64 t, struct trace_seq *s)
396 {
397 unsigned long usecs_rem;
398
399 usecs_rem = do_div(t, NSEC_PER_SEC);
400 usecs_rem /= 1000;
401
402 return trace_seq_printf(s, "%5lu.%06lu | ",
403 (unsigned long)t, usecs_rem);
404 }
405
406 static enum print_line_t
407 print_graph_irq(struct trace_iterator *iter, unsigned long addr,
408 enum trace_type type, int cpu, pid_t pid)
409 {
410 int ret;
411 struct trace_seq *s = &iter->seq;
412
413 if (addr < (unsigned long)__irqentry_text_start ||
414 addr >= (unsigned long)__irqentry_text_end)
415 return TRACE_TYPE_UNHANDLED;
416
417 /* Absolute time */
418 if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
419 ret = print_graph_abs_time(iter->ts, s);
420 if (!ret)
421 return TRACE_TYPE_PARTIAL_LINE;
422 }
423
424 /* Cpu */
425 if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
426 ret = print_graph_cpu(s, cpu);
427 if (ret == TRACE_TYPE_PARTIAL_LINE)
428 return TRACE_TYPE_PARTIAL_LINE;
429 }
430 /* Proc */
431 if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
432 ret = print_graph_proc(s, pid);
433 if (ret == TRACE_TYPE_PARTIAL_LINE)
434 return TRACE_TYPE_PARTIAL_LINE;
435 ret = trace_seq_printf(s, " | ");
436 if (!ret)
437 return TRACE_TYPE_PARTIAL_LINE;
438 }
439
440 /* No overhead */
441 ret = print_graph_overhead(-1, s);
442 if (!ret)
443 return TRACE_TYPE_PARTIAL_LINE;
444
445 if (type == TRACE_GRAPH_ENT)
446 ret = trace_seq_printf(s, "==========>");
447 else
448 ret = trace_seq_printf(s, "<==========");
449
450 if (!ret)
451 return TRACE_TYPE_PARTIAL_LINE;
452
453 /* Don't close the duration column if haven't one */
454 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
455 trace_seq_printf(s, " |");
456 ret = trace_seq_printf(s, "\n");
457
458 if (!ret)
459 return TRACE_TYPE_PARTIAL_LINE;
460 return TRACE_TYPE_HANDLED;
461 }
462
463 enum print_line_t
464 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
465 {
466 unsigned long nsecs_rem = do_div(duration, 1000);
467 /* log10(ULONG_MAX) + '\0' */
468 char msecs_str[21];
469 char nsecs_str[5];
470 int ret, len;
471 int i;
472
473 sprintf(msecs_str, "%lu", (unsigned long) duration);
474
475 /* Print msecs */
476 ret = trace_seq_printf(s, "%s", msecs_str);
477 if (!ret)
478 return TRACE_TYPE_PARTIAL_LINE;
479
480 len = strlen(msecs_str);
481
482 /* Print nsecs (we don't want to exceed 7 numbers) */
483 if (len < 7) {
484 snprintf(nsecs_str, 8 - len, "%03lu", nsecs_rem);
485 ret = trace_seq_printf(s, ".%s", nsecs_str);
486 if (!ret)
487 return TRACE_TYPE_PARTIAL_LINE;
488 len += strlen(nsecs_str);
489 }
490
491 ret = trace_seq_printf(s, " us ");
492 if (!ret)
493 return TRACE_TYPE_PARTIAL_LINE;
494
495 /* Print remaining spaces to fit the row's width */
496 for (i = len; i < 7; i++) {
497 ret = trace_seq_printf(s, " ");
498 if (!ret)
499 return TRACE_TYPE_PARTIAL_LINE;
500 }
501 return TRACE_TYPE_HANDLED;
502 }
503
504 static enum print_line_t
505 print_graph_duration(unsigned long long duration, struct trace_seq *s)
506 {
507 int ret;
508
509 ret = trace_print_graph_duration(duration, s);
510 if (ret != TRACE_TYPE_HANDLED)
511 return ret;
512
513 ret = trace_seq_printf(s, "| ");
514 if (!ret)
515 return TRACE_TYPE_PARTIAL_LINE;
516
517 return TRACE_TYPE_HANDLED;
518 }
519
520 /* Case of a leaf function on its call entry */
521 static enum print_line_t
522 print_graph_entry_leaf(struct trace_iterator *iter,
523 struct ftrace_graph_ent_entry *entry,
524 struct ftrace_graph_ret_entry *ret_entry, struct trace_seq *s)
525 {
526 struct fgraph_data *data = iter->private;
527 struct ftrace_graph_ret *graph_ret;
528 struct ftrace_graph_ent *call;
529 unsigned long long duration;
530 int ret;
531 int i;
532
533 graph_ret = &ret_entry->ret;
534 call = &entry->graph_ent;
535 duration = graph_ret->rettime - graph_ret->calltime;
536
537 if (data) {
538 int cpu = iter->cpu;
539 int *depth = &(per_cpu_ptr(data, cpu)->depth);
540
541 /*
542 * Comments display at + 1 to depth. Since
543 * this is a leaf function, keep the comments
544 * equal to this depth.
545 */
546 *depth = call->depth - 1;
547 }
548
549 /* Overhead */
550 ret = print_graph_overhead(duration, s);
551 if (!ret)
552 return TRACE_TYPE_PARTIAL_LINE;
553
554 /* Duration */
555 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
556 ret = print_graph_duration(duration, s);
557 if (ret == TRACE_TYPE_PARTIAL_LINE)
558 return TRACE_TYPE_PARTIAL_LINE;
559 }
560
561 /* Function */
562 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
563 ret = trace_seq_printf(s, " ");
564 if (!ret)
565 return TRACE_TYPE_PARTIAL_LINE;
566 }
567
568 ret = seq_print_ip_sym(s, call->func, 0);
569 if (!ret)
570 return TRACE_TYPE_PARTIAL_LINE;
571
572 ret = trace_seq_printf(s, "();\n");
573 if (!ret)
574 return TRACE_TYPE_PARTIAL_LINE;
575
576 return TRACE_TYPE_HANDLED;
577 }
578
579 static enum print_line_t
580 print_graph_entry_nested(struct trace_iterator *iter,
581 struct ftrace_graph_ent_entry *entry,
582 struct trace_seq *s, int cpu)
583 {
584 struct ftrace_graph_ent *call = &entry->graph_ent;
585 struct fgraph_data *data = iter->private;
586 int ret;
587 int i;
588
589 if (data) {
590 int cpu = iter->cpu;
591 int *depth = &(per_cpu_ptr(data, cpu)->depth);
592
593 *depth = call->depth;
594 }
595
596 /* No overhead */
597 ret = print_graph_overhead(-1, s);
598 if (!ret)
599 return TRACE_TYPE_PARTIAL_LINE;
600
601 /* No time */
602 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
603 ret = trace_seq_printf(s, " | ");
604 if (!ret)
605 return TRACE_TYPE_PARTIAL_LINE;
606 }
607
608 /* Function */
609 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
610 ret = trace_seq_printf(s, " ");
611 if (!ret)
612 return TRACE_TYPE_PARTIAL_LINE;
613 }
614
615 ret = seq_print_ip_sym(s, call->func, 0);
616 if (!ret)
617 return TRACE_TYPE_PARTIAL_LINE;
618
619 ret = trace_seq_printf(s, "() {\n");
620 if (!ret)
621 return TRACE_TYPE_PARTIAL_LINE;
622
623 /*
624 * we already consumed the current entry to check the next one
625 * and see if this is a leaf.
626 */
627 return TRACE_TYPE_NO_CONSUME;
628 }
629
630 static enum print_line_t
631 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
632 int type, unsigned long addr)
633 {
634 struct fgraph_data *data = iter->private;
635 struct trace_entry *ent = iter->ent;
636 int cpu = iter->cpu;
637 int ret;
638
639 /* Pid */
640 if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)
641 return TRACE_TYPE_PARTIAL_LINE;
642
643 if (type) {
644 /* Interrupt */
645 ret = print_graph_irq(iter, addr, type, cpu, ent->pid);
646 if (ret == TRACE_TYPE_PARTIAL_LINE)
647 return TRACE_TYPE_PARTIAL_LINE;
648 }
649
650 /* Absolute time */
651 if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
652 ret = print_graph_abs_time(iter->ts, s);
653 if (!ret)
654 return TRACE_TYPE_PARTIAL_LINE;
655 }
656
657 /* Cpu */
658 if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
659 ret = print_graph_cpu(s, cpu);
660 if (ret == TRACE_TYPE_PARTIAL_LINE)
661 return TRACE_TYPE_PARTIAL_LINE;
662 }
663
664 /* Proc */
665 if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
666 ret = print_graph_proc(s, ent->pid);
667 if (ret == TRACE_TYPE_PARTIAL_LINE)
668 return TRACE_TYPE_PARTIAL_LINE;
669
670 ret = trace_seq_printf(s, " | ");
671 if (!ret)
672 return TRACE_TYPE_PARTIAL_LINE;
673 }
674
675 return 0;
676 }
677
678 static enum print_line_t
679 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
680 struct trace_iterator *iter)
681 {
682 int cpu = iter->cpu;
683 struct ftrace_graph_ent *call = &field->graph_ent;
684 struct ftrace_graph_ret_entry *leaf_ret;
685
686 if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func))
687 return TRACE_TYPE_PARTIAL_LINE;
688
689 leaf_ret = get_return_for_leaf(iter, field);
690 if (leaf_ret)
691 return print_graph_entry_leaf(iter, field, leaf_ret, s);
692 else
693 return print_graph_entry_nested(iter, field, s, cpu);
694
695 }
696
697 static enum print_line_t
698 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
699 struct trace_entry *ent, struct trace_iterator *iter)
700 {
701 unsigned long long duration = trace->rettime - trace->calltime;
702 struct fgraph_data *data = iter->private;
703 pid_t pid = ent->pid;
704 int cpu = iter->cpu;
705 int ret;
706 int i;
707
708 if (data) {
709 int cpu = iter->cpu;
710 int *depth = &(per_cpu_ptr(data, cpu)->depth);
711
712 /*
713 * Comments display at + 1 to depth. This is the
714 * return from a function, we now want the comments
715 * to display at the same level of the bracket.
716 */
717 *depth = trace->depth - 1;
718 }
719
720 if (print_graph_prologue(iter, s, 0, 0))
721 return TRACE_TYPE_PARTIAL_LINE;
722
723 /* Overhead */
724 ret = print_graph_overhead(duration, s);
725 if (!ret)
726 return TRACE_TYPE_PARTIAL_LINE;
727
728 /* Duration */
729 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
730 ret = print_graph_duration(duration, s);
731 if (ret == TRACE_TYPE_PARTIAL_LINE)
732 return TRACE_TYPE_PARTIAL_LINE;
733 }
734
735 /* Closing brace */
736 for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
737 ret = trace_seq_printf(s, " ");
738 if (!ret)
739 return TRACE_TYPE_PARTIAL_LINE;
740 }
741
742 ret = trace_seq_printf(s, "}\n");
743 if (!ret)
744 return TRACE_TYPE_PARTIAL_LINE;
745
746 /* Overrun */
747 if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERRUN) {
748 ret = trace_seq_printf(s, " (Overruns: %lu)\n",
749 trace->overrun);
750 if (!ret)
751 return TRACE_TYPE_PARTIAL_LINE;
752 }
753
754 ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET, cpu, pid);
755 if (ret == TRACE_TYPE_PARTIAL_LINE)
756 return TRACE_TYPE_PARTIAL_LINE;
757
758 return TRACE_TYPE_HANDLED;
759 }
760
761 static enum print_line_t
762 print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
763 struct trace_iterator *iter)
764 {
765 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
766 struct fgraph_data *data = iter->private;
767 struct trace_event *event;
768 int depth = 0;
769 int ret;
770 int i;
771
772 if (data)
773 depth = per_cpu_ptr(data, iter->cpu)->depth;
774
775 if (print_graph_prologue(iter, s, 0, 0))
776 return TRACE_TYPE_PARTIAL_LINE;
777
778 /* No overhead */
779 ret = print_graph_overhead(-1, s);
780 if (!ret)
781 return TRACE_TYPE_PARTIAL_LINE;
782
783 /* No time */
784 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
785 ret = trace_seq_printf(s, " | ");
786 if (!ret)
787 return TRACE_TYPE_PARTIAL_LINE;
788 }
789
790 /* Indentation */
791 if (depth > 0)
792 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) {
793 ret = trace_seq_printf(s, " ");
794 if (!ret)
795 return TRACE_TYPE_PARTIAL_LINE;
796 }
797
798 /* The comment */
799 ret = trace_seq_printf(s, "/* ");
800 if (!ret)
801 return TRACE_TYPE_PARTIAL_LINE;
802
803 switch (iter->ent->type) {
804 case TRACE_BPRINT:
805 ret = trace_print_bprintk_msg_only(iter);
806 if (ret != TRACE_TYPE_HANDLED)
807 return ret;
808 break;
809 case TRACE_PRINT:
810 ret = trace_print_printk_msg_only(iter);
811 if (ret != TRACE_TYPE_HANDLED)
812 return ret;
813 break;
814 default:
815 event = ftrace_find_event(ent->type);
816 if (!event)
817 return TRACE_TYPE_UNHANDLED;
818
819 ret = event->trace(iter, sym_flags);
820 if (ret != TRACE_TYPE_HANDLED)
821 return ret;
822 }
823
824 /* Strip ending newline */
825 if (s->buffer[s->len - 1] == '\n') {
826 s->buffer[s->len - 1] = '\0';
827 s->len--;
828 }
829
830 ret = trace_seq_printf(s, " */\n");
831 if (!ret)
832 return TRACE_TYPE_PARTIAL_LINE;
833
834 return TRACE_TYPE_HANDLED;
835 }
836
837
838 enum print_line_t
839 print_graph_function(struct trace_iterator *iter)
840 {
841 struct trace_entry *entry = iter->ent;
842 struct trace_seq *s = &iter->seq;
843
844 switch (entry->type) {
845 case TRACE_GRAPH_ENT: {
846 /*
847 * print_graph_entry() may consume the current event,
848 * thus @field may become invalid, so we need to save it.
849 * sizeof(struct ftrace_graph_ent_entry) is very small,
850 * it can be safely saved at the stack.
851 */
852 struct ftrace_graph_ent_entry *field, saved;
853 trace_assign_type(field, entry);
854 saved = *field;
855 return print_graph_entry(&saved, s, iter);
856 }
857 case TRACE_GRAPH_RET: {
858 struct ftrace_graph_ret_entry *field;
859 trace_assign_type(field, entry);
860 return print_graph_return(&field->ret, s, entry, iter);
861 }
862 default:
863 return print_graph_comment(s, entry, iter);
864 }
865
866 return TRACE_TYPE_HANDLED;
867 }
868
869 static void print_graph_headers(struct seq_file *s)
870 {
871 /* 1st line */
872 seq_printf(s, "# ");
873 if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
874 seq_printf(s, " TIME ");
875 if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
876 seq_printf(s, "CPU");
877 if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
878 seq_printf(s, " TASK/PID ");
879 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
880 seq_printf(s, " DURATION ");
881 seq_printf(s, " FUNCTION CALLS\n");
882
883 /* 2nd line */
884 seq_printf(s, "# ");
885 if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
886 seq_printf(s, " | ");
887 if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
888 seq_printf(s, "| ");
889 if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
890 seq_printf(s, " | | ");
891 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
892 seq_printf(s, " | | ");
893 seq_printf(s, " | | | |\n");
894 }
895
896 static void graph_trace_open(struct trace_iterator *iter)
897 {
898 /* pid and depth on the last trace processed */
899 struct fgraph_data *data = alloc_percpu(struct fgraph_data);
900 int cpu;
901
902 if (!data)
903 pr_warning("function graph tracer: not enough memory\n");
904 else
905 for_each_possible_cpu(cpu) {
906 pid_t *pid = &(per_cpu_ptr(data, cpu)->last_pid);
907 int *depth = &(per_cpu_ptr(data, cpu)->depth);
908 *pid = -1;
909 *depth = 0;
910 }
911
912 iter->private = data;
913 }
914
915 static void graph_trace_close(struct trace_iterator *iter)
916 {
917 free_percpu(iter->private);
918 }
919
920 static struct tracer graph_trace __read_mostly = {
921 .name = "function_graph",
922 .open = graph_trace_open,
923 .close = graph_trace_close,
924 .wait_pipe = poll_wait_pipe,
925 .init = graph_trace_init,
926 .reset = graph_trace_reset,
927 .print_line = print_graph_function,
928 .print_header = print_graph_headers,
929 .flags = &tracer_flags,
930 #ifdef CONFIG_FTRACE_SELFTEST
931 .selftest = trace_selftest_startup_function_graph,
932 #endif
933 };
934
935 static __init int init_graph_trace(void)
936 {
937 return register_tracer(&graph_trace);
938 }
939
940 device_initcall(init_graph_trace);
941
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