Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael...
[linux-2.6.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->trace(iter, sym_flags);
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 {
1117         return print_graph_function(iter);
1118 }
1119
1120 static void print_lat_header(struct seq_file *s, u32 flags)
1121 {
1122         static const char spaces[] = "                " /* 16 spaces */
1123                 "    "                                  /* 4 spaces */
1124                 "                 ";                    /* 17 spaces */
1125         int size = 0;
1126
1127         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1128                 size += 16;
1129         if (flags & TRACE_GRAPH_PRINT_CPU)
1130                 size += 4;
1131         if (flags & TRACE_GRAPH_PRINT_PROC)
1132                 size += 17;
1133
1134         seq_printf(s, "#%.*s  _-----=> irqs-off        \n", size, spaces);
1135         seq_printf(s, "#%.*s / _----=> need-resched    \n", size, spaces);
1136         seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
1137         seq_printf(s, "#%.*s|| / _--=> preempt-depth   \n", size, spaces);
1138         seq_printf(s, "#%.*s||| / _-=> lock-depth      \n", size, spaces);
1139         seq_printf(s, "#%.*s|||| /                     \n", size, spaces);
1140 }
1141
1142 void print_graph_headers_flags(struct seq_file *s, u32 flags)
1143 {
1144         int lat = trace_flags & TRACE_ITER_LATENCY_FMT;
1145
1146         if (lat)
1147                 print_lat_header(s, flags);
1148
1149         /* 1st line */
1150         seq_printf(s, "#");
1151         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1152                 seq_printf(s, "     TIME       ");
1153         if (flags & TRACE_GRAPH_PRINT_CPU)
1154                 seq_printf(s, " CPU");
1155         if (flags & TRACE_GRAPH_PRINT_PROC)
1156                 seq_printf(s, "  TASK/PID       ");
1157         if (lat)
1158                 seq_printf(s, "|||||");
1159         if (flags & TRACE_GRAPH_PRINT_DURATION)
1160                 seq_printf(s, "  DURATION   ");
1161         seq_printf(s, "               FUNCTION CALLS\n");
1162
1163         /* 2nd line */
1164         seq_printf(s, "#");
1165         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1166                 seq_printf(s, "      |         ");
1167         if (flags & TRACE_GRAPH_PRINT_CPU)
1168                 seq_printf(s, " |  ");
1169         if (flags & TRACE_GRAPH_PRINT_PROC)
1170                 seq_printf(s, "   |    |        ");
1171         if (lat)
1172                 seq_printf(s, "|||||");
1173         if (flags & TRACE_GRAPH_PRINT_DURATION)
1174                 seq_printf(s, "   |   |      ");
1175         seq_printf(s, "               |   |   |   |\n");
1176 }
1177
1178 void print_graph_headers(struct seq_file *s)
1179 {
1180         print_graph_headers_flags(s, tracer_flags.val);
1181 }
1182
1183 void graph_trace_open(struct trace_iterator *iter)
1184 {
1185         /* pid and depth on the last trace processed */
1186         struct fgraph_data *data;
1187         int cpu;
1188
1189         iter->private = NULL;
1190
1191         data = kzalloc(sizeof(*data), GFP_KERNEL);
1192         if (!data)
1193                 goto out_err;
1194
1195         data->cpu_data = alloc_percpu(struct fgraph_cpu_data);
1196         if (!data->cpu_data)
1197                 goto out_err_free;
1198
1199         for_each_possible_cpu(cpu) {
1200                 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
1201                 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
1202                 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
1203                 *pid = -1;
1204                 *depth = 0;
1205                 *ignore = 0;
1206         }
1207
1208         iter->private = data;
1209
1210         return;
1211
1212  out_err_free:
1213         kfree(data);
1214  out_err:
1215         pr_warning("function graph tracer: not enough memory\n");
1216 }
1217
1218 void graph_trace_close(struct trace_iterator *iter)
1219 {
1220         struct fgraph_data *data = iter->private;
1221
1222         if (data) {
1223                 free_percpu(data->cpu_data);
1224                 kfree(data);
1225         }
1226 }
1227
1228 static struct trace_event graph_trace_entry_event = {
1229         .type           = TRACE_GRAPH_ENT,
1230         .trace          = print_graph_function_event,
1231 };
1232
1233 static struct trace_event graph_trace_ret_event = {
1234         .type           = TRACE_GRAPH_RET,
1235         .trace          = print_graph_function_event,
1236 };
1237
1238 static struct tracer graph_trace __read_mostly = {
1239         .name           = "function_graph",
1240         .open           = graph_trace_open,
1241         .pipe_open      = graph_trace_open,
1242         .close          = graph_trace_close,
1243         .pipe_close     = graph_trace_close,
1244         .wait_pipe      = poll_wait_pipe,
1245         .init           = graph_trace_init,
1246         .reset          = graph_trace_reset,
1247         .print_line     = print_graph_function,
1248         .print_header   = print_graph_headers,
1249         .flags          = &tracer_flags,
1250 #ifdef CONFIG_FTRACE_SELFTEST
1251         .selftest       = trace_selftest_startup_function_graph,
1252 #endif
1253 };
1254
1255 static __init int init_graph_trace(void)
1256 {
1257         max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);
1258
1259         if (!register_ftrace_event(&graph_trace_entry_event)) {
1260                 pr_warning("Warning: could not register graph trace events\n");
1261                 return 1;
1262         }
1263
1264         if (!register_ftrace_event(&graph_trace_ret_event)) {
1265                 pr_warning("Warning: could not register graph trace events\n");
1266                 return 1;
1267         }
1268
1269         return register_tracer(&graph_trace);
1270 }
1271
1272 device_initcall(init_graph_trace);