tracing: Remove special traces
[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, min(sizeof(nsecs_str), 8UL - len), "%03lu",
645                          nsecs_rem);
646                 ret = trace_seq_printf(s, ".%s", nsecs_str);
647                 if (!ret)
648                         return TRACE_TYPE_PARTIAL_LINE;
649                 len += strlen(nsecs_str);
650         }
651
652         ret = trace_seq_printf(s, " us ");
653         if (!ret)
654                 return TRACE_TYPE_PARTIAL_LINE;
655
656         /* Print remaining spaces to fit the row's width */
657         for (i = len; i < 7; i++) {
658                 ret = trace_seq_printf(s, " ");
659                 if (!ret)
660                         return TRACE_TYPE_PARTIAL_LINE;
661         }
662         return TRACE_TYPE_HANDLED;
663 }
664
665 static enum print_line_t
666 print_graph_duration(unsigned long long duration, struct trace_seq *s)
667 {
668         int ret;
669
670         ret = trace_print_graph_duration(duration, s);
671         if (ret != TRACE_TYPE_HANDLED)
672                 return ret;
673
674         ret = trace_seq_printf(s, "|  ");
675         if (!ret)
676                 return TRACE_TYPE_PARTIAL_LINE;
677
678         return TRACE_TYPE_HANDLED;
679 }
680
681 /* Case of a leaf function on its call entry */
682 static enum print_line_t
683 print_graph_entry_leaf(struct trace_iterator *iter,
684                 struct ftrace_graph_ent_entry *entry,
685                 struct ftrace_graph_ret_entry *ret_entry,
686                 struct trace_seq *s, u32 flags)
687 {
688         struct fgraph_data *data = iter->private;
689         struct ftrace_graph_ret *graph_ret;
690         struct ftrace_graph_ent *call;
691         unsigned long long duration;
692         int ret;
693         int i;
694
695         graph_ret = &ret_entry->ret;
696         call = &entry->graph_ent;
697         duration = graph_ret->rettime - graph_ret->calltime;
698
699         if (data) {
700                 struct fgraph_cpu_data *cpu_data;
701                 int cpu = iter->cpu;
702
703                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
704
705                 /*
706                  * Comments display at + 1 to depth. Since
707                  * this is a leaf function, keep the comments
708                  * equal to this depth.
709                  */
710                 cpu_data->depth = call->depth - 1;
711
712                 /* No need to keep this function around for this depth */
713                 if (call->depth < FTRACE_RETFUNC_DEPTH)
714                         cpu_data->enter_funcs[call->depth] = 0;
715         }
716
717         /* Overhead */
718         ret = print_graph_overhead(duration, s, flags);
719         if (!ret)
720                 return TRACE_TYPE_PARTIAL_LINE;
721
722         /* Duration */
723         if (flags & TRACE_GRAPH_PRINT_DURATION) {
724                 ret = print_graph_duration(duration, s);
725                 if (ret == TRACE_TYPE_PARTIAL_LINE)
726                         return TRACE_TYPE_PARTIAL_LINE;
727         }
728
729         /* Function */
730         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
731                 ret = trace_seq_printf(s, " ");
732                 if (!ret)
733                         return TRACE_TYPE_PARTIAL_LINE;
734         }
735
736         ret = trace_seq_printf(s, "%ps();\n", (void *)call->func);
737         if (!ret)
738                 return TRACE_TYPE_PARTIAL_LINE;
739
740         return TRACE_TYPE_HANDLED;
741 }
742
743 static enum print_line_t
744 print_graph_entry_nested(struct trace_iterator *iter,
745                          struct ftrace_graph_ent_entry *entry,
746                          struct trace_seq *s, int cpu, u32 flags)
747 {
748         struct ftrace_graph_ent *call = &entry->graph_ent;
749         struct fgraph_data *data = iter->private;
750         int ret;
751         int i;
752
753         if (data) {
754                 struct fgraph_cpu_data *cpu_data;
755                 int cpu = iter->cpu;
756
757                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
758                 cpu_data->depth = call->depth;
759
760                 /* Save this function pointer to see if the exit matches */
761                 if (call->depth < FTRACE_RETFUNC_DEPTH)
762                         cpu_data->enter_funcs[call->depth] = call->func;
763         }
764
765         /* No overhead */
766         ret = print_graph_overhead(-1, s, flags);
767         if (!ret)
768                 return TRACE_TYPE_PARTIAL_LINE;
769
770         /* No time */
771         if (flags & TRACE_GRAPH_PRINT_DURATION) {
772                 ret = trace_seq_printf(s, "            |  ");
773                 if (!ret)
774                         return TRACE_TYPE_PARTIAL_LINE;
775         }
776
777         /* Function */
778         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
779                 ret = trace_seq_printf(s, " ");
780                 if (!ret)
781                         return TRACE_TYPE_PARTIAL_LINE;
782         }
783
784         ret = trace_seq_printf(s, "%ps() {\n", (void *)call->func);
785         if (!ret)
786                 return TRACE_TYPE_PARTIAL_LINE;
787
788         /*
789          * we already consumed the current entry to check the next one
790          * and see if this is a leaf.
791          */
792         return TRACE_TYPE_NO_CONSUME;
793 }
794
795 static enum print_line_t
796 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
797                      int type, unsigned long addr, u32 flags)
798 {
799         struct fgraph_data *data = iter->private;
800         struct trace_entry *ent = iter->ent;
801         int cpu = iter->cpu;
802         int ret;
803
804         /* Pid */
805         if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)
806                 return TRACE_TYPE_PARTIAL_LINE;
807
808         if (type) {
809                 /* Interrupt */
810                 ret = print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
811                 if (ret == TRACE_TYPE_PARTIAL_LINE)
812                         return TRACE_TYPE_PARTIAL_LINE;
813         }
814
815         /* Absolute time */
816         if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {
817                 ret = print_graph_abs_time(iter->ts, s);
818                 if (!ret)
819                         return TRACE_TYPE_PARTIAL_LINE;
820         }
821
822         /* Cpu */
823         if (flags & TRACE_GRAPH_PRINT_CPU) {
824                 ret = print_graph_cpu(s, cpu);
825                 if (ret == TRACE_TYPE_PARTIAL_LINE)
826                         return TRACE_TYPE_PARTIAL_LINE;
827         }
828
829         /* Proc */
830         if (flags & TRACE_GRAPH_PRINT_PROC) {
831                 ret = print_graph_proc(s, ent->pid);
832                 if (ret == TRACE_TYPE_PARTIAL_LINE)
833                         return TRACE_TYPE_PARTIAL_LINE;
834
835                 ret = trace_seq_printf(s, " | ");
836                 if (!ret)
837                         return TRACE_TYPE_PARTIAL_LINE;
838         }
839
840         /* Latency format */
841         if (trace_flags & TRACE_ITER_LATENCY_FMT) {
842                 ret = print_graph_lat_fmt(s, ent);
843                 if (ret == TRACE_TYPE_PARTIAL_LINE)
844                         return TRACE_TYPE_PARTIAL_LINE;
845         }
846
847         return 0;
848 }
849
850 static enum print_line_t
851 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
852                         struct trace_iterator *iter, u32 flags)
853 {
854         struct fgraph_data *data = iter->private;
855         struct ftrace_graph_ent *call = &field->graph_ent;
856         struct ftrace_graph_ret_entry *leaf_ret;
857         static enum print_line_t ret;
858         int cpu = iter->cpu;
859
860         if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags))
861                 return TRACE_TYPE_PARTIAL_LINE;
862
863         leaf_ret = get_return_for_leaf(iter, field);
864         if (leaf_ret)
865                 ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags);
866         else
867                 ret = print_graph_entry_nested(iter, field, s, cpu, flags);
868
869         if (data) {
870                 /*
871                  * If we failed to write our output, then we need to make
872                  * note of it. Because we already consumed our entry.
873                  */
874                 if (s->full) {
875                         data->failed = 1;
876                         data->cpu = cpu;
877                 } else
878                         data->failed = 0;
879         }
880
881         return ret;
882 }
883
884 static enum print_line_t
885 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
886                    struct trace_entry *ent, struct trace_iterator *iter,
887                    u32 flags)
888 {
889         unsigned long long duration = trace->rettime - trace->calltime;
890         struct fgraph_data *data = iter->private;
891         pid_t pid = ent->pid;
892         int cpu = iter->cpu;
893         int func_match = 1;
894         int ret;
895         int i;
896
897         if (data) {
898                 struct fgraph_cpu_data *cpu_data;
899                 int cpu = iter->cpu;
900
901                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
902
903                 /*
904                  * Comments display at + 1 to depth. This is the
905                  * return from a function, we now want the comments
906                  * to display at the same level of the bracket.
907                  */
908                 cpu_data->depth = trace->depth - 1;
909
910                 if (trace->depth < FTRACE_RETFUNC_DEPTH) {
911                         if (cpu_data->enter_funcs[trace->depth] != trace->func)
912                                 func_match = 0;
913                         cpu_data->enter_funcs[trace->depth] = 0;
914                 }
915         }
916
917         if (print_graph_prologue(iter, s, 0, 0, flags))
918                 return TRACE_TYPE_PARTIAL_LINE;
919
920         /* Overhead */
921         ret = print_graph_overhead(duration, s, flags);
922         if (!ret)
923                 return TRACE_TYPE_PARTIAL_LINE;
924
925         /* Duration */
926         if (flags & TRACE_GRAPH_PRINT_DURATION) {
927                 ret = print_graph_duration(duration, s);
928                 if (ret == TRACE_TYPE_PARTIAL_LINE)
929                         return TRACE_TYPE_PARTIAL_LINE;
930         }
931
932         /* Closing brace */
933         for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
934                 ret = trace_seq_printf(s, " ");
935                 if (!ret)
936                         return TRACE_TYPE_PARTIAL_LINE;
937         }
938
939         /*
940          * If the return function does not have a matching entry,
941          * then the entry was lost. Instead of just printing
942          * the '}' and letting the user guess what function this
943          * belongs to, write out the function name.
944          */
945         if (func_match) {
946                 ret = trace_seq_printf(s, "}\n");
947                 if (!ret)
948                         return TRACE_TYPE_PARTIAL_LINE;
949         } else {
950                 ret = trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
951                 if (!ret)
952                         return TRACE_TYPE_PARTIAL_LINE;
953         }
954
955         /* Overrun */
956         if (flags & TRACE_GRAPH_PRINT_OVERRUN) {
957                 ret = trace_seq_printf(s, " (Overruns: %lu)\n",
958                                         trace->overrun);
959                 if (!ret)
960                         return TRACE_TYPE_PARTIAL_LINE;
961         }
962
963         ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
964                               cpu, pid, flags);
965         if (ret == TRACE_TYPE_PARTIAL_LINE)
966                 return TRACE_TYPE_PARTIAL_LINE;
967
968         return TRACE_TYPE_HANDLED;
969 }
970
971 static enum print_line_t
972 print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
973                     struct trace_iterator *iter, u32 flags)
974 {
975         unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
976         struct fgraph_data *data = iter->private;
977         struct trace_event *event;
978         int depth = 0;
979         int ret;
980         int i;
981
982         if (data)
983                 depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
984
985         if (print_graph_prologue(iter, s, 0, 0, flags))
986                 return TRACE_TYPE_PARTIAL_LINE;
987
988         /* No overhead */
989         ret = print_graph_overhead(-1, s, flags);
990         if (!ret)
991                 return TRACE_TYPE_PARTIAL_LINE;
992
993         /* No time */
994         if (flags & TRACE_GRAPH_PRINT_DURATION) {
995                 ret = trace_seq_printf(s, "            |  ");
996                 if (!ret)
997                         return TRACE_TYPE_PARTIAL_LINE;
998         }
999
1000         /* Indentation */
1001         if (depth > 0)
1002                 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) {
1003                         ret = trace_seq_printf(s, " ");
1004                         if (!ret)
1005                                 return TRACE_TYPE_PARTIAL_LINE;
1006                 }
1007
1008         /* The comment */
1009         ret = trace_seq_printf(s, "/* ");
1010         if (!ret)
1011                 return TRACE_TYPE_PARTIAL_LINE;
1012
1013         switch (iter->ent->type) {
1014         case TRACE_BPRINT:
1015                 ret = trace_print_bprintk_msg_only(iter);
1016                 if (ret != TRACE_TYPE_HANDLED)
1017                         return ret;
1018                 break;
1019         case TRACE_PRINT:
1020                 ret = trace_print_printk_msg_only(iter);
1021                 if (ret != TRACE_TYPE_HANDLED)
1022                         return ret;
1023                 break;
1024         default:
1025                 event = ftrace_find_event(ent->type);
1026                 if (!event)
1027                         return TRACE_TYPE_UNHANDLED;
1028
1029                 ret = event->funcs->trace(iter, sym_flags, event);
1030                 if (ret != TRACE_TYPE_HANDLED)
1031                         return ret;
1032         }
1033
1034         /* Strip ending newline */
1035         if (s->buffer[s->len - 1] == '\n') {
1036                 s->buffer[s->len - 1] = '\0';
1037                 s->len--;
1038         }
1039
1040         ret = trace_seq_printf(s, " */\n");
1041         if (!ret)
1042                 return TRACE_TYPE_PARTIAL_LINE;
1043
1044         return TRACE_TYPE_HANDLED;
1045 }
1046
1047
1048 enum print_line_t
1049 print_graph_function_flags(struct trace_iterator *iter, u32 flags)
1050 {
1051         struct ftrace_graph_ent_entry *field;
1052         struct fgraph_data *data = iter->private;
1053         struct trace_entry *entry = iter->ent;
1054         struct trace_seq *s = &iter->seq;
1055         int cpu = iter->cpu;
1056         int ret;
1057
1058         if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
1059                 per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
1060                 return TRACE_TYPE_HANDLED;
1061         }
1062
1063         /*
1064          * If the last output failed, there's a possibility we need
1065          * to print out the missing entry which would never go out.
1066          */
1067         if (data && data->failed) {
1068                 field = &data->ent;
1069                 iter->cpu = data->cpu;
1070                 ret = print_graph_entry(field, s, iter, flags);
1071                 if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
1072                         per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
1073                         ret = TRACE_TYPE_NO_CONSUME;
1074                 }
1075                 iter->cpu = cpu;
1076                 return ret;
1077         }
1078
1079         switch (entry->type) {
1080         case TRACE_GRAPH_ENT: {
1081                 /*
1082                  * print_graph_entry() may consume the current event,
1083                  * thus @field may become invalid, so we need to save it.
1084                  * sizeof(struct ftrace_graph_ent_entry) is very small,
1085                  * it can be safely saved at the stack.
1086                  */
1087                 struct ftrace_graph_ent_entry saved;
1088                 trace_assign_type(field, entry);
1089                 saved = *field;
1090                 return print_graph_entry(&saved, s, iter, flags);
1091         }
1092         case TRACE_GRAPH_RET: {
1093                 struct ftrace_graph_ret_entry *field;
1094                 trace_assign_type(field, entry);
1095                 return print_graph_return(&field->ret, s, entry, iter, flags);
1096         }
1097         case TRACE_STACK:
1098         case TRACE_FN:
1099                 /* dont trace stack and functions as comments */
1100                 return TRACE_TYPE_UNHANDLED;
1101
1102         default:
1103                 return print_graph_comment(s, entry, iter, flags);
1104         }
1105
1106         return TRACE_TYPE_HANDLED;
1107 }
1108
1109 static enum print_line_t
1110 print_graph_function(struct trace_iterator *iter)
1111 {
1112         return print_graph_function_flags(iter, tracer_flags.val);
1113 }
1114
1115 static enum print_line_t
1116 print_graph_function_event(struct trace_iterator *iter, int flags,
1117                            struct trace_event *event)
1118 {
1119         return print_graph_function(iter);
1120 }
1121
1122 static void print_lat_header(struct seq_file *s, u32 flags)
1123 {
1124         static const char spaces[] = "                " /* 16 spaces */
1125                 "    "                                  /* 4 spaces */
1126                 "                 ";                    /* 17 spaces */
1127         int size = 0;
1128
1129         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1130                 size += 16;
1131         if (flags & TRACE_GRAPH_PRINT_CPU)
1132                 size += 4;
1133         if (flags & TRACE_GRAPH_PRINT_PROC)
1134                 size += 17;
1135
1136         seq_printf(s, "#%.*s  _-----=> irqs-off        \n", size, spaces);
1137         seq_printf(s, "#%.*s / _----=> need-resched    \n", size, spaces);
1138         seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
1139         seq_printf(s, "#%.*s|| / _--=> preempt-depth   \n", size, spaces);
1140         seq_printf(s, "#%.*s||| / _-=> lock-depth      \n", size, spaces);
1141         seq_printf(s, "#%.*s|||| /                     \n", size, spaces);
1142 }
1143
1144 void print_graph_headers_flags(struct seq_file *s, u32 flags)
1145 {
1146         int lat = trace_flags & TRACE_ITER_LATENCY_FMT;
1147
1148         if (lat)
1149                 print_lat_header(s, flags);
1150
1151         /* 1st line */
1152         seq_printf(s, "#");
1153         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1154                 seq_printf(s, "     TIME       ");
1155         if (flags & TRACE_GRAPH_PRINT_CPU)
1156                 seq_printf(s, " CPU");
1157         if (flags & TRACE_GRAPH_PRINT_PROC)
1158                 seq_printf(s, "  TASK/PID       ");
1159         if (lat)
1160                 seq_printf(s, "|||||");
1161         if (flags & TRACE_GRAPH_PRINT_DURATION)
1162                 seq_printf(s, "  DURATION   ");
1163         seq_printf(s, "               FUNCTION CALLS\n");
1164
1165         /* 2nd line */
1166         seq_printf(s, "#");
1167         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1168                 seq_printf(s, "      |         ");
1169         if (flags & TRACE_GRAPH_PRINT_CPU)
1170                 seq_printf(s, " |  ");
1171         if (flags & TRACE_GRAPH_PRINT_PROC)
1172                 seq_printf(s, "   |    |        ");
1173         if (lat)
1174                 seq_printf(s, "|||||");
1175         if (flags & TRACE_GRAPH_PRINT_DURATION)
1176                 seq_printf(s, "   |   |      ");
1177         seq_printf(s, "               |   |   |   |\n");
1178 }
1179
1180 void print_graph_headers(struct seq_file *s)
1181 {
1182         print_graph_headers_flags(s, tracer_flags.val);
1183 }
1184
1185 void graph_trace_open(struct trace_iterator *iter)
1186 {
1187         /* pid and depth on the last trace processed */
1188         struct fgraph_data *data;
1189         int cpu;
1190
1191         iter->private = NULL;
1192
1193         data = kzalloc(sizeof(*data), GFP_KERNEL);
1194         if (!data)
1195                 goto out_err;
1196
1197         data->cpu_data = alloc_percpu(struct fgraph_cpu_data);
1198         if (!data->cpu_data)
1199                 goto out_err_free;
1200
1201         for_each_possible_cpu(cpu) {
1202                 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
1203                 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
1204                 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
1205                 *pid = -1;
1206                 *depth = 0;
1207                 *ignore = 0;
1208         }
1209
1210         iter->private = data;
1211
1212         return;
1213
1214  out_err_free:
1215         kfree(data);
1216  out_err:
1217         pr_warning("function graph tracer: not enough memory\n");
1218 }
1219
1220 void graph_trace_close(struct trace_iterator *iter)
1221 {
1222         struct fgraph_data *data = iter->private;
1223
1224         if (data) {
1225                 free_percpu(data->cpu_data);
1226                 kfree(data);
1227         }
1228 }
1229
1230 static struct trace_event_functions graph_functions = {
1231         .trace          = print_graph_function_event,
1232 };
1233
1234 static struct trace_event graph_trace_entry_event = {
1235         .type           = TRACE_GRAPH_ENT,
1236         .funcs          = &graph_functions,
1237 };
1238
1239 static struct trace_event graph_trace_ret_event = {
1240         .type           = TRACE_GRAPH_RET,
1241         .funcs          = &graph_functions
1242 };
1243
1244 static struct tracer graph_trace __read_mostly = {
1245         .name           = "function_graph",
1246         .open           = graph_trace_open,
1247         .pipe_open      = graph_trace_open,
1248         .close          = graph_trace_close,
1249         .pipe_close     = graph_trace_close,
1250         .wait_pipe      = poll_wait_pipe,
1251         .init           = graph_trace_init,
1252         .reset          = graph_trace_reset,
1253         .print_line     = print_graph_function,
1254         .print_header   = print_graph_headers,
1255         .flags          = &tracer_flags,
1256 #ifdef CONFIG_FTRACE_SELFTEST
1257         .selftest       = trace_selftest_startup_function_graph,
1258 #endif
1259 };
1260
1261 static __init int init_graph_trace(void)
1262 {
1263         max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);
1264
1265         if (!register_ftrace_event(&graph_trace_entry_event)) {
1266                 pr_warning("Warning: could not register graph trace events\n");
1267                 return 1;
1268         }
1269
1270         if (!register_ftrace_event(&graph_trace_ret_event)) {
1271                 pr_warning("Warning: could not register graph trace events\n");
1272                 return 1;
1273         }
1274
1275         return register_tracer(&graph_trace);
1276 }
1277
1278 device_initcall(init_graph_trace);