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tracing: Fix an unallocated memory access in function_graph
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / kernel / trace / trace_functions_graph.c
blob72a0d96facc2f60c63467117a7e53fcf9ce4d7bf
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 static 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 static 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, NULL);
494 event = ring_buffer_peek(iter->tr->buffer, iter->cpu,
495 NULL);
496 }
497
498 if (!event)
499 return NULL;
500
501 next = ring_buffer_event_data(event);
502
503 if (data) {
504 /*
505 * Save current and next entries for later reference
506 * if the output fails.
507 */
508 data->ent = *curr;
509 /*
510 * If the next event is not a return type, then
511 * we only care about what type it is. Otherwise we can
512 * safely copy the entire event.
513 */
514 if (next->ent.type == TRACE_GRAPH_RET)
515 data->ret = *next;
516 else
517 data->ret.ent.type = next->ent.type;
518 }
519 }
520
521 if (next->ent.type != TRACE_GRAPH_RET)
522 return NULL;
523
524 if (curr->ent.pid != next->ent.pid ||
525 curr->graph_ent.func != next->ret.func)
526 return NULL;
527
528 /* this is a leaf, now advance the iterator */
529 if (ring_iter)
530 ring_buffer_read(ring_iter, NULL);
531
532 return next;
533 }
534
535 /* Signal a overhead of time execution to the output */
536 static int
537 print_graph_overhead(unsigned long long duration, struct trace_seq *s)
538 {
539 /* If duration disappear, we don't need anything */
540 if (!(tracer_flags.val & TRACE_GRAPH_PRINT_DURATION))
541 return 1;
542
543 /* Non nested entry or return */
544 if (duration == -1)
545 return trace_seq_printf(s, " ");
546
547 if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
548 /* Duration exceeded 100 msecs */
549 if (duration > 100000ULL)
550 return trace_seq_printf(s, "! ");
551
552 /* Duration exceeded 10 msecs */
553 if (duration > 10000ULL)
554 return trace_seq_printf(s, "+ ");
555 }
556
557 return trace_seq_printf(s, " ");
558 }
559
560 static int print_graph_abs_time(u64 t, struct trace_seq *s)
561 {
562 unsigned long usecs_rem;
563
564 usecs_rem = do_div(t, NSEC_PER_SEC);
565 usecs_rem /= 1000;
566
567 return trace_seq_printf(s, "%5lu.%06lu | ",
568 (unsigned long)t, usecs_rem);
569 }
570
571 static enum print_line_t
572 print_graph_irq(struct trace_iterator *iter, unsigned long addr,
573 enum trace_type type, int cpu, pid_t pid)
574 {
575 int ret;
576 struct trace_seq *s = &iter->seq;
577
578 if (addr < (unsigned long)__irqentry_text_start ||
579 addr >= (unsigned long)__irqentry_text_end)
580 return TRACE_TYPE_UNHANDLED;
581
582 /* Absolute time */
583 if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
584 ret = print_graph_abs_time(iter->ts, s);
585 if (!ret)
586 return TRACE_TYPE_PARTIAL_LINE;
587 }
588
589 /* Cpu */
590 if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
591 ret = print_graph_cpu(s, cpu);
592 if (ret == TRACE_TYPE_PARTIAL_LINE)
593 return TRACE_TYPE_PARTIAL_LINE;
594 }
595
596 /* Proc */
597 if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
598 ret = print_graph_proc(s, pid);
599 if (ret == TRACE_TYPE_PARTIAL_LINE)
600 return TRACE_TYPE_PARTIAL_LINE;
601 ret = trace_seq_printf(s, " | ");
602 if (!ret)
603 return TRACE_TYPE_PARTIAL_LINE;
604 }
605
606 /* No overhead */
607 ret = print_graph_overhead(-1, s);
608 if (!ret)
609 return TRACE_TYPE_PARTIAL_LINE;
610
611 if (type == TRACE_GRAPH_ENT)
612 ret = trace_seq_printf(s, "==========>");
613 else
614 ret = trace_seq_printf(s, "<==========");
615
616 if (!ret)
617 return TRACE_TYPE_PARTIAL_LINE;
618
619 /* Don't close the duration column if haven't one */
620 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
621 trace_seq_printf(s, " |");
622 ret = trace_seq_printf(s, "\n");
623
624 if (!ret)
625 return TRACE_TYPE_PARTIAL_LINE;
626 return TRACE_TYPE_HANDLED;
627 }
628
629 enum print_line_t
630 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
631 {
632 unsigned long nsecs_rem = do_div(duration, 1000);
633 /* log10(ULONG_MAX) + '\0' */
634 char msecs_str[21];
635 char nsecs_str[5];
636 int ret, len;
637 int i;
638
639 sprintf(msecs_str, "%lu", (unsigned long) duration);
640
641 /* Print msecs */
642 ret = trace_seq_printf(s, "%s", msecs_str);
643 if (!ret)
644 return TRACE_TYPE_PARTIAL_LINE;
645
646 len = strlen(msecs_str);
647
648 /* Print nsecs (we don't want to exceed 7 numbers) */
649 if (len < 7) {
650 snprintf(nsecs_str, 8 - len, "%03lu", nsecs_rem);
651 ret = trace_seq_printf(s, ".%s", nsecs_str);
652 if (!ret)
653 return TRACE_TYPE_PARTIAL_LINE;
654 len += strlen(nsecs_str);
655 }
656
657 ret = trace_seq_printf(s, " us ");
658 if (!ret)
659 return TRACE_TYPE_PARTIAL_LINE;
660
661 /* Print remaining spaces to fit the row's width */
662 for (i = len; i < 7; i++) {
663 ret = trace_seq_printf(s, " ");
664 if (!ret)
665 return TRACE_TYPE_PARTIAL_LINE;
666 }
667 return TRACE_TYPE_HANDLED;
668 }
669
670 static enum print_line_t
671 print_graph_duration(unsigned long long duration, struct trace_seq *s)
672 {
673 int ret;
674
675 ret = trace_print_graph_duration(duration, s);
676 if (ret != TRACE_TYPE_HANDLED)
677 return ret;
678
679 ret = trace_seq_printf(s, "| ");
680 if (!ret)
681 return TRACE_TYPE_PARTIAL_LINE;
682
683 return TRACE_TYPE_HANDLED;
684 }
685
686 /* Case of a leaf function on its call entry */
687 static enum print_line_t
688 print_graph_entry_leaf(struct trace_iterator *iter,
689 struct ftrace_graph_ent_entry *entry,
690 struct ftrace_graph_ret_entry *ret_entry, struct trace_seq *s)
691 {
692 struct fgraph_data *data = iter->private;
693 struct ftrace_graph_ret *graph_ret;
694 struct ftrace_graph_ent *call;
695 unsigned long long duration;
696 int ret;
697 int i;
698
699 graph_ret = &ret_entry->ret;
700 call = &entry->graph_ent;
701 duration = graph_ret->rettime - graph_ret->calltime;
702
703 if (data) {
704 struct fgraph_cpu_data *cpu_data;
705 int cpu = iter->cpu;
706
707 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
708
709 /*
710 * Comments display at + 1 to depth. Since
711 * this is a leaf function, keep the comments
712 * equal to this depth.
713 */
714 cpu_data->depth = call->depth - 1;
715
716 /* No need to keep this function around for this depth */
717 if (call->depth < FTRACE_RETFUNC_DEPTH)
718 cpu_data->enter_funcs[call->depth] = 0;
719 }
720
721 /* Overhead */
722 ret = print_graph_overhead(duration, s);
723 if (!ret)
724 return TRACE_TYPE_PARTIAL_LINE;
725
726 /* Duration */
727 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
728 ret = print_graph_duration(duration, s);
729 if (ret == TRACE_TYPE_PARTIAL_LINE)
730 return TRACE_TYPE_PARTIAL_LINE;
731 }
732
733 /* Function */
734 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
735 ret = trace_seq_printf(s, " ");
736 if (!ret)
737 return TRACE_TYPE_PARTIAL_LINE;
738 }
739
740 ret = trace_seq_printf(s, "%ps();\n", (void *)call->func);
741 if (!ret)
742 return TRACE_TYPE_PARTIAL_LINE;
743
744 return TRACE_TYPE_HANDLED;
745 }
746
747 static enum print_line_t
748 print_graph_entry_nested(struct trace_iterator *iter,
749 struct ftrace_graph_ent_entry *entry,
750 struct trace_seq *s, int cpu)
751 {
752 struct ftrace_graph_ent *call = &entry->graph_ent;
753 struct fgraph_data *data = iter->private;
754 int ret;
755 int i;
756
757 if (data) {
758 struct fgraph_cpu_data *cpu_data;
759 int cpu = iter->cpu;
760
761 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
762 cpu_data->depth = call->depth;
763
764 /* Save this function pointer to see if the exit matches */
765 if (call->depth < FTRACE_RETFUNC_DEPTH)
766 cpu_data->enter_funcs[call->depth] = call->func;
767 }
768
769 /* No overhead */
770 ret = print_graph_overhead(-1, s);
771 if (!ret)
772 return TRACE_TYPE_PARTIAL_LINE;
773
774 /* No time */
775 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
776 ret = trace_seq_printf(s, " | ");
777 if (!ret)
778 return TRACE_TYPE_PARTIAL_LINE;
779 }
780
781 /* Function */
782 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
783 ret = trace_seq_printf(s, " ");
784 if (!ret)
785 return TRACE_TYPE_PARTIAL_LINE;
786 }
787
788 ret = trace_seq_printf(s, "%ps() {\n", (void *)call->func);
789 if (!ret)
790 return TRACE_TYPE_PARTIAL_LINE;
791
792 /*
793 * we already consumed the current entry to check the next one
794 * and see if this is a leaf.
795 */
796 return TRACE_TYPE_NO_CONSUME;
797 }
798
799 static enum print_line_t
800 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
801 int type, unsigned long addr)
802 {
803 struct fgraph_data *data = iter->private;
804 struct trace_entry *ent = iter->ent;
805 int cpu = iter->cpu;
806 int ret;
807
808 /* Pid */
809 if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)
810 return TRACE_TYPE_PARTIAL_LINE;
811
812 if (type) {
813 /* Interrupt */
814 ret = print_graph_irq(iter, addr, type, cpu, ent->pid);
815 if (ret == TRACE_TYPE_PARTIAL_LINE)
816 return TRACE_TYPE_PARTIAL_LINE;
817 }
818
819 /* Absolute time */
820 if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
821 ret = print_graph_abs_time(iter->ts, s);
822 if (!ret)
823 return TRACE_TYPE_PARTIAL_LINE;
824 }
825
826 /* Cpu */
827 if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
828 ret = print_graph_cpu(s, cpu);
829 if (ret == TRACE_TYPE_PARTIAL_LINE)
830 return TRACE_TYPE_PARTIAL_LINE;
831 }
832
833 /* Proc */
834 if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
835 ret = print_graph_proc(s, ent->pid);
836 if (ret == TRACE_TYPE_PARTIAL_LINE)
837 return TRACE_TYPE_PARTIAL_LINE;
838
839 ret = trace_seq_printf(s, " | ");
840 if (!ret)
841 return TRACE_TYPE_PARTIAL_LINE;
842 }
843
844 /* Latency format */
845 if (trace_flags & TRACE_ITER_LATENCY_FMT) {
846 ret = print_graph_lat_fmt(s, ent);
847 if (ret == TRACE_TYPE_PARTIAL_LINE)
848 return TRACE_TYPE_PARTIAL_LINE;
849 }
850
851 return 0;
852 }
853
854 static enum print_line_t
855 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
856 struct trace_iterator *iter)
857 {
858 struct fgraph_data *data = iter->private;
859 struct ftrace_graph_ent *call = &field->graph_ent;
860 struct ftrace_graph_ret_entry *leaf_ret;
861 static enum print_line_t ret;
862 int cpu = iter->cpu;
863
864 if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func))
865 return TRACE_TYPE_PARTIAL_LINE;
866
867 leaf_ret = get_return_for_leaf(iter, field);
868 if (leaf_ret)
869 ret = print_graph_entry_leaf(iter, field, leaf_ret, s);
870 else
871 ret = print_graph_entry_nested(iter, field, s, cpu);
872
873 if (data) {
874 /*
875 * If we failed to write our output, then we need to make
876 * note of it. Because we already consumed our entry.
877 */
878 if (s->full) {
879 data->failed = 1;
880 data->cpu = cpu;
881 } else
882 data->failed = 0;
883 }
884
885 return ret;
886 }
887
888 static enum print_line_t
889 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
890 struct trace_entry *ent, struct trace_iterator *iter)
891 {
892 unsigned long long duration = trace->rettime - trace->calltime;
893 struct fgraph_data *data = iter->private;
894 pid_t pid = ent->pid;
895 int cpu = iter->cpu;
896 int func_match = 1;
897 int ret;
898 int i;
899
900 if (data) {
901 struct fgraph_cpu_data *cpu_data;
902 int cpu = iter->cpu;
903
904 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
905
906 /*
907 * Comments display at + 1 to depth. This is the
908 * return from a function, we now want the comments
909 * to display at the same level of the bracket.
910 */
911 cpu_data->depth = trace->depth - 1;
912
913 if (trace->depth < FTRACE_RETFUNC_DEPTH) {
914 if (cpu_data->enter_funcs[trace->depth] != trace->func)
915 func_match = 0;
916 cpu_data->enter_funcs[trace->depth] = 0;
917 }
918 }
919
920 if (print_graph_prologue(iter, s, 0, 0))
921 return TRACE_TYPE_PARTIAL_LINE;
922
923 /* Overhead */
924 ret = print_graph_overhead(duration, s);
925 if (!ret)
926 return TRACE_TYPE_PARTIAL_LINE;
927
928 /* Duration */
929 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
930 ret = print_graph_duration(duration, s);
931 if (ret == TRACE_TYPE_PARTIAL_LINE)
932 return TRACE_TYPE_PARTIAL_LINE;
933 }
934
935 /* Closing brace */
936 for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
937 ret = trace_seq_printf(s, " ");
938 if (!ret)
939 return TRACE_TYPE_PARTIAL_LINE;
940 }
941
942 /*
943 * If the return function does not have a matching entry,
944 * then the entry was lost. Instead of just printing
945 * the '}' and letting the user guess what function this
946 * belongs to, write out the function name.
947 */
948 if (func_match) {
949 ret = trace_seq_printf(s, "}\n");
950 if (!ret)
951 return TRACE_TYPE_PARTIAL_LINE;
952 } else {
953 ret = trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
954 if (!ret)
955 return TRACE_TYPE_PARTIAL_LINE;
956 }
957
958 /* Overrun */
959 if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERRUN) {
960 ret = trace_seq_printf(s, " (Overruns: %lu)\n",
961 trace->overrun);
962 if (!ret)
963 return TRACE_TYPE_PARTIAL_LINE;
964 }
965
966 ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET, cpu, pid);
967 if (ret == TRACE_TYPE_PARTIAL_LINE)
968 return TRACE_TYPE_PARTIAL_LINE;
969
970 return TRACE_TYPE_HANDLED;
971 }
972
973 static enum print_line_t
974 print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
975 struct trace_iterator *iter)
976 {
977 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
978 struct fgraph_data *data = iter->private;
979 struct trace_event *event;
980 int depth = 0;
981 int ret;
982 int i;
983
984 if (data)
985 depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
986
987 if (print_graph_prologue(iter, s, 0, 0))
988 return TRACE_TYPE_PARTIAL_LINE;
989
990 /* No overhead */
991 ret = print_graph_overhead(-1, s);
992 if (!ret)
993 return TRACE_TYPE_PARTIAL_LINE;
994
995 /* No time */
996 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
997 ret = trace_seq_printf(s, " | ");
998 if (!ret)
999 return TRACE_TYPE_PARTIAL_LINE;
1000 }
1001
1002 /* Indentation */
1003 if (depth > 0)
1004 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) {
1005 ret = trace_seq_printf(s, " ");
1006 if (!ret)
1007 return TRACE_TYPE_PARTIAL_LINE;
1008 }
1009
1010 /* The comment */
1011 ret = trace_seq_printf(s, "/* ");
1012 if (!ret)
1013 return TRACE_TYPE_PARTIAL_LINE;
1014
1015 switch (iter->ent->type) {
1016 case TRACE_BPRINT:
1017 ret = trace_print_bprintk_msg_only(iter);
1018 if (ret != TRACE_TYPE_HANDLED)
1019 return ret;
1020 break;
1021 case TRACE_PRINT:
1022 ret = trace_print_printk_msg_only(iter);
1023 if (ret != TRACE_TYPE_HANDLED)
1024 return ret;
1025 break;
1026 default:
1027 event = ftrace_find_event(ent->type);
1028 if (!event)
1029 return TRACE_TYPE_UNHANDLED;
1030
1031 ret = event->trace(iter, sym_flags);
1032 if (ret != TRACE_TYPE_HANDLED)
1033 return ret;
1034 }
1035
1036 /* Strip ending newline */
1037 if (s->buffer[s->len - 1] == '\n') {
1038 s->buffer[s->len - 1] = '\0';
1039 s->len--;
1040 }
1041
1042 ret = trace_seq_printf(s, " */\n");
1043 if (!ret)
1044 return TRACE_TYPE_PARTIAL_LINE;
1045
1046 return TRACE_TYPE_HANDLED;
1047 }
1048
1049
1050 enum print_line_t
1051 print_graph_function(struct trace_iterator *iter)
1052 {
1053 struct ftrace_graph_ent_entry *field;
1054 struct fgraph_data *data = iter->private;
1055 struct trace_entry *entry = iter->ent;
1056 struct trace_seq *s = &iter->seq;
1057 int cpu = iter->cpu;
1058 int ret;
1059
1060 if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
1061 per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
1062 return TRACE_TYPE_HANDLED;
1063 }
1064
1065 /*
1066 * If the last output failed, there's a possibility we need
1067 * to print out the missing entry which would never go out.
1068 */
1069 if (data && data->failed) {
1070 field = &data->ent;
1071 iter->cpu = data->cpu;
1072 ret = print_graph_entry(field, s, iter);
1073 if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
1074 per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
1075 ret = TRACE_TYPE_NO_CONSUME;
1076 }
1077 iter->cpu = cpu;
1078 return ret;
1079 }
1080
1081 switch (entry->type) {
1082 case TRACE_GRAPH_ENT: {
1083 /*
1084 * print_graph_entry() may consume the current event,
1085 * thus @field may become invalid, so we need to save it.
1086 * sizeof(struct ftrace_graph_ent_entry) is very small,
1087 * it can be safely saved at the stack.
1088 */
1089 struct ftrace_graph_ent_entry saved;
1090 trace_assign_type(field, entry);
1091 saved = *field;
1092 return print_graph_entry(&saved, s, iter);
1093 }
1094 case TRACE_GRAPH_RET: {
1095 struct ftrace_graph_ret_entry *field;
1096 trace_assign_type(field, entry);
1097 return print_graph_return(&field->ret, s, entry, iter);
1098 }
1099 default:
1100 return print_graph_comment(s, entry, iter);
1101 }
1102
1103 return TRACE_TYPE_HANDLED;
1104 }
1105
1106 static void print_lat_header(struct seq_file *s)
1107 {
1108 static const char spaces[] = " " /* 16 spaces */
1109 " " /* 4 spaces */
1110 " "; /* 17 spaces */
1111 int size = 0;
1112
1113 if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
1114 size += 16;
1115 if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
1116 size += 4;
1117 if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
1118 size += 17;
1119
1120 seq_printf(s, "#%.*s _-----=> irqs-off \n", size, spaces);
1121 seq_printf(s, "#%.*s / _----=> need-resched \n", size, spaces);
1122 seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
1123 seq_printf(s, "#%.*s|| / _--=> preempt-depth \n", size, spaces);
1124 seq_printf(s, "#%.*s||| / _-=> lock-depth \n", size, spaces);
1125 seq_printf(s, "#%.*s|||| / \n", size, spaces);
1126 }
1127
1128 static void print_graph_headers(struct seq_file *s)
1129 {
1130 int lat = trace_flags & TRACE_ITER_LATENCY_FMT;
1131
1132 if (lat)
1133 print_lat_header(s);
1134
1135 /* 1st line */
1136 seq_printf(s, "#");
1137 if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
1138 seq_printf(s, " TIME ");
1139 if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
1140 seq_printf(s, " CPU");
1141 if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
1142 seq_printf(s, " TASK/PID ");
1143 if (lat)
1144 seq_printf(s, "|||||");
1145 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
1146 seq_printf(s, " DURATION ");
1147 seq_printf(s, " FUNCTION CALLS\n");
1148
1149 /* 2nd line */
1150 seq_printf(s, "#");
1151 if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
1152 seq_printf(s, " | ");
1153 if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
1154 seq_printf(s, " | ");
1155 if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
1156 seq_printf(s, " | | ");
1157 if (lat)
1158 seq_printf(s, "|||||");
1159 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
1160 seq_printf(s, " | | ");
1161 seq_printf(s, " | | | |\n");
1162 }
1163
1164 static void graph_trace_open(struct trace_iterator *iter)
1165 {
1166 /* pid and depth on the last trace processed */
1167 struct fgraph_data *data;
1168 int cpu;
1169
1170 iter->private = NULL;
1171
1172 data = kzalloc(sizeof(*data), GFP_KERNEL);
1173 if (!data)
1174 goto out_err;
1175
1176 data->cpu_data = alloc_percpu(struct fgraph_cpu_data);
1177 if (!data->cpu_data)
1178 goto out_err_free;
1179
1180 for_each_possible_cpu(cpu) {
1181 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
1182 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
1183 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
1184 *pid = -1;
1185 *depth = 0;
1186 *ignore = 0;
1187 }
1188
1189 iter->private = data;
1190
1191 return;
1192
1193 out_err_free:
1194 kfree(data);
1195 out_err:
1196 pr_warning("function graph tracer: not enough memory\n");
1197 }
1198
1199 static void graph_trace_close(struct trace_iterator *iter)
1200 {
1201 struct fgraph_data *data = iter->private;
1202
1203 if (data) {
1204 free_percpu(data->cpu_data);
1205 kfree(data);
1206 }
1207 }
1208
1209 static struct tracer graph_trace __read_mostly = {
1210 .name = "function_graph",
1211 .open = graph_trace_open,
1212 .pipe_open = graph_trace_open,
1213 .close = graph_trace_close,
1214 .pipe_close = graph_trace_close,
1215 .wait_pipe = poll_wait_pipe,
1216 .init = graph_trace_init,
1217 .reset = graph_trace_reset,
1218 .print_line = print_graph_function,
1219 .print_header = print_graph_headers,
1220 .flags = &tracer_flags,
1221 #ifdef CONFIG_FTRACE_SELFTEST
1222 .selftest = trace_selftest_startup_function_graph,
1223 #endif
1224 };
1225
1226 static __init int init_graph_trace(void)
1227 {
1228 max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);
1229
1230 return register_tracer(&graph_trace);
1231 }
1232
1233 device_initcall(init_graph_trace);
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree