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Merge tag 'v3.10.55' into update
[GitHub/mt8127/android_kernel_alcatel_ttab.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 /* When set, irq functions will be ignored */
19 static int ftrace_graph_skip_irqs;
20
21 struct fgraph_cpu_data {
22 pid_t last_pid;
23 int depth;
24 int depth_irq;
25 int ignore;
26 unsigned long enter_funcs[FTRACE_RETFUNC_DEPTH];
27 };
28
29 struct fgraph_data {
30 struct fgraph_cpu_data __percpu *cpu_data;
31
32 /* Place to preserve last processed entry. */
33 struct ftrace_graph_ent_entry ent;
34 struct ftrace_graph_ret_entry ret;
35 int failed;
36 int cpu;
37 };
38
39 #define TRACE_GRAPH_INDENT 2
40
41 /* Flag options */
42 #define TRACE_GRAPH_PRINT_OVERRUN 0x1
43 #define TRACE_GRAPH_PRINT_CPU 0x2
44 #define TRACE_GRAPH_PRINT_OVERHEAD 0x4
45 #define TRACE_GRAPH_PRINT_PROC 0x8
46 #define TRACE_GRAPH_PRINT_DURATION 0x10
47 #define TRACE_GRAPH_PRINT_ABS_TIME 0x20
48 #define TRACE_GRAPH_PRINT_IRQS 0x40
49 #define TRACE_GRAPH_PRINT_FLAT 0x80
50
51
52 static unsigned int max_depth;
53
54 static struct tracer_opt trace_opts[] = {
55 /* Display overruns? (for self-debug purpose) */
56 { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
57 /* Display CPU ? */
58 { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
59 /* Display Overhead ? */
60 { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
61 /* Display proc name/pid */
62 { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
63 /* Display duration of execution */
64 { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
65 /* Display absolute time of an entry */
66 { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
67 /* Display interrupts */
68 { TRACER_OPT(funcgraph-irqs, TRACE_GRAPH_PRINT_IRQS) },
69 /* Use standard trace formatting rather than hierarchical */
70 { TRACER_OPT(funcgraph-flat, TRACE_GRAPH_PRINT_FLAT) },
71 { } /* Empty entry */
72 };
73
74 static struct tracer_flags tracer_flags = {
75 /* Don't display overruns and proc by default */
76 .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
77 TRACE_GRAPH_PRINT_DURATION | TRACE_GRAPH_PRINT_IRQS,
78 .opts = trace_opts
79 };
80
81 static struct trace_array *graph_array;
82
83 /*
84 * DURATION column is being also used to display IRQ signs,
85 * following values are used by print_graph_irq and others
86 * to fill in space into DURATION column.
87 */
88 enum {
89 DURATION_FILL_FULL = -1,
90 DURATION_FILL_START = -2,
91 DURATION_FILL_END = -3,
92 };
93
94 static enum print_line_t
95 print_graph_duration(unsigned long long duration, struct trace_seq *s,
96 u32 flags);
97
98 /* Add a function return address to the trace stack on thread info.*/
99 int
100 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
101 unsigned long frame_pointer)
102 {
103 unsigned long long calltime;
104 int index;
105
106 if (!current->ret_stack)
107 return -EBUSY;
108
109 /*
110 * We must make sure the ret_stack is tested before we read
111 * anything else.
112 */
113 smp_rmb();
114
115 /* The return trace stack is full */
116 if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
117 atomic_inc(&current->trace_overrun);
118 return -EBUSY;
119 }
120
121 calltime = trace_clock_local();
122
123 index = ++current->curr_ret_stack;
124 barrier();
125 current->ret_stack[index].ret = ret;
126 current->ret_stack[index].func = func;
127 current->ret_stack[index].calltime = calltime;
128 current->ret_stack[index].subtime = 0;
129 current->ret_stack[index].fp = frame_pointer;
130 *depth = index;
131
132 return 0;
133 }
134
135 /* Retrieve a function return address to the trace stack on thread info.*/
136 static void
137 ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
138 unsigned long frame_pointer)
139 {
140 int index;
141
142 index = current->curr_ret_stack;
143
144 if (unlikely(index < 0)) {
145 ftrace_graph_stop();
146 WARN_ON(1);
147 /* Might as well panic, otherwise we have no where to go */
148 *ret = (unsigned long)panic;
149 return;
150 }
151
152 #if defined(CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST) && !defined(CC_USING_FENTRY)
153 /*
154 * The arch may choose to record the frame pointer used
155 * and check it here to make sure that it is what we expect it
156 * to be. If gcc does not set the place holder of the return
157 * address in the frame pointer, and does a copy instead, then
158 * the function graph trace will fail. This test detects this
159 * case.
160 *
161 * Currently, x86_32 with optimize for size (-Os) makes the latest
162 * gcc do the above.
163 *
164 * Note, -mfentry does not use frame pointers, and this test
165 * is not needed if CC_USING_FENTRY is set.
166 */
167 if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
168 ftrace_graph_stop();
169 WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
170 " from func %ps return to %lx\n",
171 current->ret_stack[index].fp,
172 frame_pointer,
173 (void *)current->ret_stack[index].func,
174 current->ret_stack[index].ret);
175 *ret = (unsigned long)panic;
176 return;
177 }
178 #endif
179
180 *ret = current->ret_stack[index].ret;
181 trace->func = current->ret_stack[index].func;
182 trace->calltime = current->ret_stack[index].calltime;
183 trace->overrun = atomic_read(&current->trace_overrun);
184 trace->depth = index;
185 }
186
187 /*
188 * Send the trace to the ring-buffer.
189 * @return the original return address.
190 */
191 unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
192 {
193 struct ftrace_graph_ret trace;
194 unsigned long ret;
195
196 ftrace_pop_return_trace(&trace, &ret, frame_pointer);
197 trace.rettime = trace_clock_local();
198 barrier();
199 current->curr_ret_stack--;
200
201 /*
202 * The trace should run after decrementing the ret counter
203 * in case an interrupt were to come in. We don't want to
204 * lose the interrupt if max_depth is set.
205 */
206 ftrace_graph_return(&trace);
207
208 if (unlikely(!ret)) {
209 ftrace_graph_stop();
210 WARN_ON(1);
211 /* Might as well panic. What else to do? */
212 ret = (unsigned long)panic;
213 }
214
215 return ret;
216 }
217
218 int __trace_graph_entry(struct trace_array *tr,
219 struct ftrace_graph_ent *trace,
220 unsigned long flags,
221 int pc)
222 {
223 struct ftrace_event_call *call = &event_funcgraph_entry;
224 struct ring_buffer_event *event;
225 struct ring_buffer *buffer = tr->trace_buffer.buffer;
226 struct ftrace_graph_ent_entry *entry;
227
228 if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
229 return 0;
230
231 event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
232 sizeof(*entry), flags, pc);
233 if (!event)
234 return 0;
235 entry = ring_buffer_event_data(event);
236 entry->graph_ent = *trace;
237 if (!filter_current_check_discard(buffer, call, entry, event))
238 __buffer_unlock_commit(buffer, event);
239
240 return 1;
241 }
242
243 static inline int ftrace_graph_ignore_irqs(void)
244 {
245 if (!ftrace_graph_skip_irqs || trace_recursion_test(TRACE_IRQ_BIT))
246 return 0;
247
248 return in_irq();
249 }
250
251 int trace_graph_entry(struct ftrace_graph_ent *trace)
252 {
253 struct trace_array *tr = graph_array;
254 struct trace_array_cpu *data;
255 unsigned long flags;
256 long disabled;
257 int ret;
258 int cpu;
259 int pc;
260
261 if (!ftrace_trace_task(current))
262 return 0;
263
264 /* trace it when it is-nested-in or is a function enabled. */
265 if ((!(trace->depth || ftrace_graph_addr(trace->func)) ||
266 ftrace_graph_ignore_irqs()) ||
267 (max_depth && trace->depth >= max_depth))
268 return 0;
269
270 local_irq_save(flags);
271 cpu = raw_smp_processor_id();
272 data = per_cpu_ptr(tr->trace_buffer.data, cpu);
273 disabled = atomic_inc_return(&data->disabled);
274 if (likely(disabled == 1)) {
275 pc = preempt_count();
276 ret = __trace_graph_entry(tr, trace, flags, pc);
277 } else {
278 ret = 0;
279 }
280
281 atomic_dec(&data->disabled);
282 local_irq_restore(flags);
283
284 return ret;
285 }
286
287 int trace_graph_thresh_entry(struct ftrace_graph_ent *trace)
288 {
289 if (tracing_thresh)
290 return 1;
291 else
292 return trace_graph_entry(trace);
293 }
294
295 static void
296 __trace_graph_function(struct trace_array *tr,
297 unsigned long ip, unsigned long flags, int pc)
298 {
299 u64 time = trace_clock_local();
300 struct ftrace_graph_ent ent = {
301 .func = ip,
302 .depth = 0,
303 };
304 struct ftrace_graph_ret ret = {
305 .func = ip,
306 .depth = 0,
307 .calltime = time,
308 .rettime = time,
309 };
310
311 __trace_graph_entry(tr, &ent, flags, pc);
312 __trace_graph_return(tr, &ret, flags, pc);
313 }
314
315 void
316 trace_graph_function(struct trace_array *tr,
317 unsigned long ip, unsigned long parent_ip,
318 unsigned long flags, int pc)
319 {
320 __trace_graph_function(tr, ip, flags, pc);
321 }
322
323 void __trace_graph_return(struct trace_array *tr,
324 struct ftrace_graph_ret *trace,
325 unsigned long flags,
326 int pc)
327 {
328 struct ftrace_event_call *call = &event_funcgraph_exit;
329 struct ring_buffer_event *event;
330 struct ring_buffer *buffer = tr->trace_buffer.buffer;
331 struct ftrace_graph_ret_entry *entry;
332
333 if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
334 return;
335
336 event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
337 sizeof(*entry), flags, pc);
338 if (!event)
339 return;
340 entry = ring_buffer_event_data(event);
341 entry->ret = *trace;
342 if (!filter_current_check_discard(buffer, call, entry, event))
343 __buffer_unlock_commit(buffer, event);
344 }
345
346 void trace_graph_return(struct ftrace_graph_ret *trace)
347 {
348 struct trace_array *tr = graph_array;
349 struct trace_array_cpu *data;
350 unsigned long flags;
351 long disabled;
352 int cpu;
353 int pc;
354
355 local_irq_save(flags);
356 cpu = raw_smp_processor_id();
357 data = per_cpu_ptr(tr->trace_buffer.data, cpu);
358 disabled = atomic_inc_return(&data->disabled);
359 if (likely(disabled == 1)) {
360 pc = preempt_count();
361 __trace_graph_return(tr, trace, flags, pc);
362 }
363 atomic_dec(&data->disabled);
364 local_irq_restore(flags);
365 }
366
367 void set_graph_array(struct trace_array *tr)
368 {
369 graph_array = tr;
370
371 /* Make graph_array visible before we start tracing */
372
373 smp_mb();
374 }
375
376 void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
377 {
378 if (tracing_thresh &&
379 (trace->rettime - trace->calltime < tracing_thresh))
380 return;
381 else
382 trace_graph_return(trace);
383 }
384
385 static int graph_trace_init(struct trace_array *tr)
386 {
387 int ret;
388
389 set_graph_array(tr);
390 if (tracing_thresh)
391 ret = register_ftrace_graph(&trace_graph_thresh_return,
392 &trace_graph_thresh_entry);
393 else
394 ret = register_ftrace_graph(&trace_graph_return,
395 &trace_graph_entry);
396 if (ret)
397 return ret;
398 tracing_start_cmdline_record();
399
400 return 0;
401 }
402
403 static void graph_trace_reset(struct trace_array *tr)
404 {
405 tracing_stop_cmdline_record();
406 unregister_ftrace_graph();
407 }
408
409 static int max_bytes_for_cpu;
410
411 static enum print_line_t
412 print_graph_cpu(struct trace_seq *s, int cpu)
413 {
414 int ret;
415
416 /*
417 * Start with a space character - to make it stand out
418 * to the right a bit when trace output is pasted into
419 * email:
420 */
421 ret = trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
422 if (!ret)
423 return TRACE_TYPE_PARTIAL_LINE;
424
425 return TRACE_TYPE_HANDLED;
426 }
427
428 #define TRACE_GRAPH_PROCINFO_LENGTH 14
429
430 static enum print_line_t
431 print_graph_proc(struct trace_seq *s, pid_t pid)
432 {
433 char comm[TASK_COMM_LEN];
434 /* sign + log10(MAX_INT) + '\0' */
435 char pid_str[11];
436 int spaces = 0;
437 int ret;
438 int len;
439 int i;
440
441 trace_find_cmdline(pid, comm);
442 comm[7] = '\0';
443 sprintf(pid_str, "%d", pid);
444
445 /* 1 stands for the "-" character */
446 len = strlen(comm) + strlen(pid_str) + 1;
447
448 if (len < TRACE_GRAPH_PROCINFO_LENGTH)
449 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
450
451 /* First spaces to align center */
452 for (i = 0; i < spaces / 2; i++) {
453 ret = trace_seq_printf(s, " ");
454 if (!ret)
455 return TRACE_TYPE_PARTIAL_LINE;
456 }
457
458 ret = trace_seq_printf(s, "%s-%s", comm, pid_str);
459 if (!ret)
460 return TRACE_TYPE_PARTIAL_LINE;
461
462 /* Last spaces to align center */
463 for (i = 0; i < spaces - (spaces / 2); i++) {
464 ret = trace_seq_printf(s, " ");
465 if (!ret)
466 return TRACE_TYPE_PARTIAL_LINE;
467 }
468 return TRACE_TYPE_HANDLED;
469 }
470
471
472 static enum print_line_t
473 print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
474 {
475 if (!trace_seq_putc(s, ' '))
476 return 0;
477
478 return trace_print_lat_fmt(s, entry);
479 }
480
481 /* If the pid changed since the last trace, output this event */
482 static enum print_line_t
483 verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
484 {
485 pid_t prev_pid;
486 pid_t *last_pid;
487 int ret;
488
489 if (!data)
490 return TRACE_TYPE_HANDLED;
491
492 last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
493
494 if (*last_pid == pid)
495 return TRACE_TYPE_HANDLED;
496
497 prev_pid = *last_pid;
498 *last_pid = pid;
499
500 if (prev_pid == -1)
501 return TRACE_TYPE_HANDLED;
502 /*
503 * Context-switch trace line:
504
505 ------------------------------------------
506 | 1) migration/0--1 => sshd-1755
507 ------------------------------------------
508
509 */
510 ret = trace_seq_printf(s,
511 " ------------------------------------------\n");
512 if (!ret)
513 return TRACE_TYPE_PARTIAL_LINE;
514
515 ret = print_graph_cpu(s, cpu);
516 if (ret == TRACE_TYPE_PARTIAL_LINE)
517 return TRACE_TYPE_PARTIAL_LINE;
518
519 ret = print_graph_proc(s, prev_pid);
520 if (ret == TRACE_TYPE_PARTIAL_LINE)
521 return TRACE_TYPE_PARTIAL_LINE;
522
523 ret = trace_seq_printf(s, " => ");
524 if (!ret)
525 return TRACE_TYPE_PARTIAL_LINE;
526
527 ret = print_graph_proc(s, pid);
528 if (ret == TRACE_TYPE_PARTIAL_LINE)
529 return TRACE_TYPE_PARTIAL_LINE;
530
531 ret = trace_seq_printf(s,
532 "\n ------------------------------------------\n\n");
533 if (!ret)
534 return TRACE_TYPE_PARTIAL_LINE;
535
536 return TRACE_TYPE_HANDLED;
537 }
538
539 static struct ftrace_graph_ret_entry *
540 get_return_for_leaf(struct trace_iterator *iter,
541 struct ftrace_graph_ent_entry *curr)
542 {
543 struct fgraph_data *data = iter->private;
544 struct ring_buffer_iter *ring_iter = NULL;
545 struct ring_buffer_event *event;
546 struct ftrace_graph_ret_entry *next;
547
548 /*
549 * If the previous output failed to write to the seq buffer,
550 * then we just reuse the data from before.
551 */
552 if (data && data->failed) {
553 curr = &data->ent;
554 next = &data->ret;
555 } else {
556
557 ring_iter = trace_buffer_iter(iter, iter->cpu);
558
559 /* First peek to compare current entry and the next one */
560 if (ring_iter)
561 event = ring_buffer_iter_peek(ring_iter, NULL);
562 else {
563 /*
564 * We need to consume the current entry to see
565 * the next one.
566 */
567 ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu,
568 NULL, NULL);
569 event = ring_buffer_peek(iter->trace_buffer->buffer, iter->cpu,
570 NULL, NULL);
571 }
572
573 if (!event)
574 return NULL;
575
576 next = ring_buffer_event_data(event);
577
578 if (data) {
579 /*
580 * Save current and next entries for later reference
581 * if the output fails.
582 */
583 data->ent = *curr;
584 /*
585 * If the next event is not a return type, then
586 * we only care about what type it is. Otherwise we can
587 * safely copy the entire event.
588 */
589 if (next->ent.type == TRACE_GRAPH_RET)
590 data->ret = *next;
591 else
592 data->ret.ent.type = next->ent.type;
593 }
594 }
595
596 if (next->ent.type != TRACE_GRAPH_RET)
597 return NULL;
598
599 if (curr->ent.pid != next->ent.pid ||
600 curr->graph_ent.func != next->ret.func)
601 return NULL;
602
603 /* this is a leaf, now advance the iterator */
604 if (ring_iter)
605 ring_buffer_read(ring_iter, NULL);
606
607 return next;
608 }
609
610 static int print_graph_abs_time(u64 t, struct trace_seq *s)
611 {
612 unsigned long usecs_rem;
613
614 usecs_rem = do_div(t, NSEC_PER_SEC);
615 usecs_rem /= 1000;
616
617 return trace_seq_printf(s, "%5lu.%06lu | ",
618 (unsigned long)t, usecs_rem);
619 }
620
621 static enum print_line_t
622 print_graph_irq(struct trace_iterator *iter, unsigned long addr,
623 enum trace_type type, int cpu, pid_t pid, u32 flags)
624 {
625 int ret;
626 struct trace_seq *s = &iter->seq;
627
628 if (addr < (unsigned long)__irqentry_text_start ||
629 addr >= (unsigned long)__irqentry_text_end)
630 return TRACE_TYPE_UNHANDLED;
631
632 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
633 /* Absolute time */
634 if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {
635 ret = print_graph_abs_time(iter->ts, s);
636 if (!ret)
637 return TRACE_TYPE_PARTIAL_LINE;
638 }
639
640 /* Cpu */
641 if (flags & TRACE_GRAPH_PRINT_CPU) {
642 ret = print_graph_cpu(s, cpu);
643 if (ret == TRACE_TYPE_PARTIAL_LINE)
644 return TRACE_TYPE_PARTIAL_LINE;
645 }
646
647 /* Proc */
648 if (flags & TRACE_GRAPH_PRINT_PROC) {
649 ret = print_graph_proc(s, pid);
650 if (ret == TRACE_TYPE_PARTIAL_LINE)
651 return TRACE_TYPE_PARTIAL_LINE;
652 ret = trace_seq_printf(s, " | ");
653 if (!ret)
654 return TRACE_TYPE_PARTIAL_LINE;
655 }
656 }
657
658 /* No overhead */
659 ret = print_graph_duration(DURATION_FILL_START, s, flags);
660 if (ret != TRACE_TYPE_HANDLED)
661 return ret;
662
663 if (type == TRACE_GRAPH_ENT)
664 ret = trace_seq_printf(s, "==========>");
665 else
666 ret = trace_seq_printf(s, "<==========");
667
668 if (!ret)
669 return TRACE_TYPE_PARTIAL_LINE;
670
671 ret = print_graph_duration(DURATION_FILL_END, s, flags);
672 if (ret != TRACE_TYPE_HANDLED)
673 return ret;
674
675 ret = trace_seq_printf(s, "\n");
676
677 if (!ret)
678 return TRACE_TYPE_PARTIAL_LINE;
679 return TRACE_TYPE_HANDLED;
680 }
681
682 enum print_line_t
683 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
684 {
685 unsigned long nsecs_rem = do_div(duration, 1000);
686 /* log10(ULONG_MAX) + '\0' */
687 char msecs_str[21];
688 char nsecs_str[5];
689 int ret, len;
690 int i;
691
692 sprintf(msecs_str, "%lu", (unsigned long) duration);
693
694 /* Print msecs */
695 ret = trace_seq_printf(s, "%s", msecs_str);
696 if (!ret)
697 return TRACE_TYPE_PARTIAL_LINE;
698
699 len = strlen(msecs_str);
700
701 /* Print nsecs (we don't want to exceed 7 numbers) */
702 if (len < 7) {
703 size_t slen = min_t(size_t, sizeof(nsecs_str), 8UL - len);
704
705 snprintf(nsecs_str, slen, "%03lu", nsecs_rem);
706 ret = trace_seq_printf(s, ".%s", nsecs_str);
707 if (!ret)
708 return TRACE_TYPE_PARTIAL_LINE;
709 len += strlen(nsecs_str);
710 }
711
712 ret = trace_seq_printf(s, " us ");
713 if (!ret)
714 return TRACE_TYPE_PARTIAL_LINE;
715
716 /* Print remaining spaces to fit the row's width */
717 for (i = len; i < 7; i++) {
718 ret = trace_seq_printf(s, " ");
719 if (!ret)
720 return TRACE_TYPE_PARTIAL_LINE;
721 }
722 return TRACE_TYPE_HANDLED;
723 }
724
725 static enum print_line_t
726 print_graph_duration(unsigned long long duration, struct trace_seq *s,
727 u32 flags)
728 {
729 int ret = -1;
730
731 if (!(flags & TRACE_GRAPH_PRINT_DURATION) ||
732 !(trace_flags & TRACE_ITER_CONTEXT_INFO))
733 return TRACE_TYPE_HANDLED;
734
735 /* No real adata, just filling the column with spaces */
736 switch (duration) {
737 case DURATION_FILL_FULL:
738 ret = trace_seq_printf(s, " | ");
739 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
740 case DURATION_FILL_START:
741 ret = trace_seq_printf(s, " ");
742 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
743 case DURATION_FILL_END:
744 ret = trace_seq_printf(s, " |");
745 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
746 }
747
748 /* Signal a overhead of time execution to the output */
749 if (flags & TRACE_GRAPH_PRINT_OVERHEAD) {
750 /* Duration exceeded 100 msecs */
751 if (duration > 100000ULL)
752 ret = trace_seq_printf(s, "! ");
753 /* Duration exceeded 10 msecs */
754 else if (duration > 10000ULL)
755 ret = trace_seq_printf(s, "+ ");
756 }
757
758 /*
759 * The -1 means we either did not exceed the duration tresholds
760 * or we dont want to print out the overhead. Either way we need
761 * to fill out the space.
762 */
763 if (ret == -1)
764 ret = trace_seq_printf(s, " ");
765
766 /* Catching here any failure happenned above */
767 if (!ret)
768 return TRACE_TYPE_PARTIAL_LINE;
769
770 ret = trace_print_graph_duration(duration, s);
771 if (ret != TRACE_TYPE_HANDLED)
772 return ret;
773
774 ret = trace_seq_printf(s, "| ");
775 if (!ret)
776 return TRACE_TYPE_PARTIAL_LINE;
777
778 return TRACE_TYPE_HANDLED;
779 }
780
781 /* Case of a leaf function on its call entry */
782 static enum print_line_t
783 print_graph_entry_leaf(struct trace_iterator *iter,
784 struct ftrace_graph_ent_entry *entry,
785 struct ftrace_graph_ret_entry *ret_entry,
786 struct trace_seq *s, u32 flags)
787 {
788 struct fgraph_data *data = iter->private;
789 struct ftrace_graph_ret *graph_ret;
790 struct ftrace_graph_ent *call;
791 unsigned long long duration;
792 int ret;
793 int i;
794
795 graph_ret = &ret_entry->ret;
796 call = &entry->graph_ent;
797 duration = graph_ret->rettime - graph_ret->calltime;
798
799 if (data) {
800 struct fgraph_cpu_data *cpu_data;
801 int cpu = iter->cpu;
802
803 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
804
805 /*
806 * Comments display at + 1 to depth. Since
807 * this is a leaf function, keep the comments
808 * equal to this depth.
809 */
810 cpu_data->depth = call->depth - 1;
811
812 /* No need to keep this function around for this depth */
813 if (call->depth < FTRACE_RETFUNC_DEPTH)
814 cpu_data->enter_funcs[call->depth] = 0;
815 }
816
817 /* Overhead and duration */
818 ret = print_graph_duration(duration, s, flags);
819 if (ret == TRACE_TYPE_PARTIAL_LINE)
820 return TRACE_TYPE_PARTIAL_LINE;
821
822 /* Function */
823 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
824 ret = trace_seq_printf(s, " ");
825 if (!ret)
826 return TRACE_TYPE_PARTIAL_LINE;
827 }
828
829 ret = trace_seq_printf(s, "%ps();\n", (void *)call->func);
830 if (!ret)
831 return TRACE_TYPE_PARTIAL_LINE;
832
833 return TRACE_TYPE_HANDLED;
834 }
835
836 static enum print_line_t
837 print_graph_entry_nested(struct trace_iterator *iter,
838 struct ftrace_graph_ent_entry *entry,
839 struct trace_seq *s, int cpu, u32 flags)
840 {
841 struct ftrace_graph_ent *call = &entry->graph_ent;
842 struct fgraph_data *data = iter->private;
843 int ret;
844 int i;
845
846 if (data) {
847 struct fgraph_cpu_data *cpu_data;
848 int cpu = iter->cpu;
849
850 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
851 cpu_data->depth = call->depth;
852
853 /* Save this function pointer to see if the exit matches */
854 if (call->depth < FTRACE_RETFUNC_DEPTH)
855 cpu_data->enter_funcs[call->depth] = call->func;
856 }
857
858 /* No time */
859 ret = print_graph_duration(DURATION_FILL_FULL, s, flags);
860 if (ret != TRACE_TYPE_HANDLED)
861 return ret;
862
863 /* Function */
864 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
865 ret = trace_seq_printf(s, " ");
866 if (!ret)
867 return TRACE_TYPE_PARTIAL_LINE;
868 }
869
870 ret = trace_seq_printf(s, "%ps() {\n", (void *)call->func);
871 if (!ret)
872 return TRACE_TYPE_PARTIAL_LINE;
873
874 /*
875 * we already consumed the current entry to check the next one
876 * and see if this is a leaf.
877 */
878 return TRACE_TYPE_NO_CONSUME;
879 }
880
881 static enum print_line_t
882 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
883 int type, unsigned long addr, u32 flags)
884 {
885 struct fgraph_data *data = iter->private;
886 struct trace_entry *ent = iter->ent;
887 int cpu = iter->cpu;
888 int ret;
889
890 /* Pid */
891 if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)
892 return TRACE_TYPE_PARTIAL_LINE;
893
894 if (type) {
895 /* Interrupt */
896 ret = print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
897 if (ret == TRACE_TYPE_PARTIAL_LINE)
898 return TRACE_TYPE_PARTIAL_LINE;
899 }
900
901 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
902 return 0;
903
904 /* Absolute time */
905 if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {
906 ret = print_graph_abs_time(iter->ts, s);
907 if (!ret)
908 return TRACE_TYPE_PARTIAL_LINE;
909 }
910
911 /* Cpu */
912 if (flags & TRACE_GRAPH_PRINT_CPU) {
913 ret = print_graph_cpu(s, cpu);
914 if (ret == TRACE_TYPE_PARTIAL_LINE)
915 return TRACE_TYPE_PARTIAL_LINE;
916 }
917
918 /* Proc */
919 if (flags & TRACE_GRAPH_PRINT_PROC) {
920 ret = print_graph_proc(s, ent->pid);
921 if (ret == TRACE_TYPE_PARTIAL_LINE)
922 return TRACE_TYPE_PARTIAL_LINE;
923
924 ret = trace_seq_printf(s, " | ");
925 if (!ret)
926 return TRACE_TYPE_PARTIAL_LINE;
927 }
928
929 /* Latency format */
930 if (trace_flags & TRACE_ITER_LATENCY_FMT) {
931 ret = print_graph_lat_fmt(s, ent);
932 if (ret == TRACE_TYPE_PARTIAL_LINE)
933 return TRACE_TYPE_PARTIAL_LINE;
934 }
935
936 return 0;
937 }
938
939 /*
940 * Entry check for irq code
941 *
942 * returns 1 if
943 * - we are inside irq code
944 * - we just entered irq code
945 *
946 * retunns 0 if
947 * - funcgraph-interrupts option is set
948 * - we are not inside irq code
949 */
950 static int
951 check_irq_entry(struct trace_iterator *iter, u32 flags,
952 unsigned long addr, int depth)
953 {
954 int cpu = iter->cpu;
955 int *depth_irq;
956 struct fgraph_data *data = iter->private;
957
958 /*
959 * If we are either displaying irqs, or we got called as
960 * a graph event and private data does not exist,
961 * then we bypass the irq check.
962 */
963 if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
964 (!data))
965 return 0;
966
967 depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
968
969 /*
970 * We are inside the irq code
971 */
972 if (*depth_irq >= 0)
973 return 1;
974
975 if ((addr < (unsigned long)__irqentry_text_start) ||
976 (addr >= (unsigned long)__irqentry_text_end))
977 return 0;
978
979 /*
980 * We are entering irq code.
981 */
982 *depth_irq = depth;
983 return 1;
984 }
985
986 /*
987 * Return check for irq code
988 *
989 * returns 1 if
990 * - we are inside irq code
991 * - we just left irq code
992 *
993 * returns 0 if
994 * - funcgraph-interrupts option is set
995 * - we are not inside irq code
996 */
997 static int
998 check_irq_return(struct trace_iterator *iter, u32 flags, int depth)
999 {
1000 int cpu = iter->cpu;
1001 int *depth_irq;
1002 struct fgraph_data *data = iter->private;
1003
1004 /*
1005 * If we are either displaying irqs, or we got called as
1006 * a graph event and private data does not exist,
1007 * then we bypass the irq check.
1008 */
1009 if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
1010 (!data))
1011 return 0;
1012
1013 depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1014
1015 /*
1016 * We are not inside the irq code.
1017 */
1018 if (*depth_irq == -1)
1019 return 0;
1020
1021 /*
1022 * We are inside the irq code, and this is returning entry.
1023 * Let's not trace it and clear the entry depth, since
1024 * we are out of irq code.
1025 *
1026 * This condition ensures that we 'leave the irq code' once
1027 * we are out of the entry depth. Thus protecting us from
1028 * the RETURN entry loss.
1029 */
1030 if (*depth_irq >= depth) {
1031 *depth_irq = -1;
1032 return 1;
1033 }
1034
1035 /*
1036 * We are inside the irq code, and this is not the entry.
1037 */
1038 return 1;
1039 }
1040
1041 static enum print_line_t
1042 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
1043 struct trace_iterator *iter, u32 flags)
1044 {
1045 struct fgraph_data *data = iter->private;
1046 struct ftrace_graph_ent *call = &field->graph_ent;
1047 struct ftrace_graph_ret_entry *leaf_ret;
1048 static enum print_line_t ret;
1049 int cpu = iter->cpu;
1050
1051 if (check_irq_entry(iter, flags, call->func, call->depth))
1052 return TRACE_TYPE_HANDLED;
1053
1054 if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags))
1055 return TRACE_TYPE_PARTIAL_LINE;
1056
1057 leaf_ret = get_return_for_leaf(iter, field);
1058 if (leaf_ret)
1059 ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags);
1060 else
1061 ret = print_graph_entry_nested(iter, field, s, cpu, flags);
1062
1063 if (data) {
1064 /*
1065 * If we failed to write our output, then we need to make
1066 * note of it. Because we already consumed our entry.
1067 */
1068 if (s->full) {
1069 data->failed = 1;
1070 data->cpu = cpu;
1071 } else
1072 data->failed = 0;
1073 }
1074
1075 return ret;
1076 }
1077
1078 static enum print_line_t
1079 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
1080 struct trace_entry *ent, struct trace_iterator *iter,
1081 u32 flags)
1082 {
1083 unsigned long long duration = trace->rettime - trace->calltime;
1084 struct fgraph_data *data = iter->private;
1085 pid_t pid = ent->pid;
1086 int cpu = iter->cpu;
1087 int func_match = 1;
1088 int ret;
1089 int i;
1090
1091 if (check_irq_return(iter, flags, trace->depth))
1092 return TRACE_TYPE_HANDLED;
1093
1094 if (data) {
1095 struct fgraph_cpu_data *cpu_data;
1096 int cpu = iter->cpu;
1097
1098 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
1099
1100 /*
1101 * Comments display at + 1 to depth. This is the
1102 * return from a function, we now want the comments
1103 * to display at the same level of the bracket.
1104 */
1105 cpu_data->depth = trace->depth - 1;
1106
1107 if (trace->depth < FTRACE_RETFUNC_DEPTH) {
1108 if (cpu_data->enter_funcs[trace->depth] != trace->func)
1109 func_match = 0;
1110 cpu_data->enter_funcs[trace->depth] = 0;
1111 }
1112 }
1113
1114 if (print_graph_prologue(iter, s, 0, 0, flags))
1115 return TRACE_TYPE_PARTIAL_LINE;
1116
1117 /* Overhead and duration */
1118 ret = print_graph_duration(duration, s, flags);
1119 if (ret == TRACE_TYPE_PARTIAL_LINE)
1120 return TRACE_TYPE_PARTIAL_LINE;
1121
1122 /* Closing brace */
1123 for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
1124 ret = trace_seq_printf(s, " ");
1125 if (!ret)
1126 return TRACE_TYPE_PARTIAL_LINE;
1127 }
1128
1129 /*
1130 * If the return function does not have a matching entry,
1131 * then the entry was lost. Instead of just printing
1132 * the '}' and letting the user guess what function this
1133 * belongs to, write out the function name.
1134 */
1135 if (func_match) {
1136 ret = trace_seq_printf(s, "}\n");
1137 if (!ret)
1138 return TRACE_TYPE_PARTIAL_LINE;
1139 } else {
1140 ret = trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
1141 if (!ret)
1142 return TRACE_TYPE_PARTIAL_LINE;
1143 }
1144
1145 /* Overrun */
1146 if (flags & TRACE_GRAPH_PRINT_OVERRUN) {
1147 ret = trace_seq_printf(s, " (Overruns: %lu)\n",
1148 trace->overrun);
1149 if (!ret)
1150 return TRACE_TYPE_PARTIAL_LINE;
1151 }
1152
1153 ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
1154 cpu, pid, flags);
1155 if (ret == TRACE_TYPE_PARTIAL_LINE)
1156 return TRACE_TYPE_PARTIAL_LINE;
1157
1158 return TRACE_TYPE_HANDLED;
1159 }
1160
1161 static enum print_line_t
1162 print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
1163 struct trace_iterator *iter, u32 flags)
1164 {
1165 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1166 struct fgraph_data *data = iter->private;
1167 struct trace_event *event;
1168 int depth = 0;
1169 int ret;
1170 int i;
1171
1172 if (data)
1173 depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
1174
1175 if (print_graph_prologue(iter, s, 0, 0, flags))
1176 return TRACE_TYPE_PARTIAL_LINE;
1177
1178 /* No time */
1179 ret = print_graph_duration(DURATION_FILL_FULL, s, flags);
1180 if (ret != TRACE_TYPE_HANDLED)
1181 return ret;
1182
1183 /* Indentation */
1184 if (depth > 0)
1185 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) {
1186 ret = trace_seq_printf(s, " ");
1187 if (!ret)
1188 return TRACE_TYPE_PARTIAL_LINE;
1189 }
1190
1191 /* The comment */
1192 ret = trace_seq_printf(s, "/* ");
1193 if (!ret)
1194 return TRACE_TYPE_PARTIAL_LINE;
1195
1196 switch (iter->ent->type) {
1197 case TRACE_BPRINT:
1198 ret = trace_print_bprintk_msg_only(iter);
1199 if (ret != TRACE_TYPE_HANDLED)
1200 return ret;
1201 break;
1202 case TRACE_PRINT:
1203 ret = trace_print_printk_msg_only(iter);
1204 if (ret != TRACE_TYPE_HANDLED)
1205 return ret;
1206 break;
1207 default:
1208 event = ftrace_find_event(ent->type);
1209 if (!event)
1210 return TRACE_TYPE_UNHANDLED;
1211
1212 ret = event->funcs->trace(iter, sym_flags, event);
1213 if (ret != TRACE_TYPE_HANDLED)
1214 return ret;
1215 }
1216
1217 /* Strip ending newline */
1218 if (s->buffer[s->len - 1] == '\n') {
1219 s->buffer[s->len - 1] = '\0';
1220 s->len--;
1221 }
1222
1223 ret = trace_seq_printf(s, " */\n");
1224 if (!ret)
1225 return TRACE_TYPE_PARTIAL_LINE;
1226
1227 return TRACE_TYPE_HANDLED;
1228 }
1229
1230
1231 enum print_line_t
1232 print_graph_function_flags(struct trace_iterator *iter, u32 flags)
1233 {
1234 struct ftrace_graph_ent_entry *field;
1235 struct fgraph_data *data = iter->private;
1236 struct trace_entry *entry = iter->ent;
1237 struct trace_seq *s = &iter->seq;
1238 int cpu = iter->cpu;
1239 int ret;
1240
1241 if (flags & TRACE_GRAPH_PRINT_FLAT)
1242 return TRACE_TYPE_UNHANDLED;
1243
1244 if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
1245 per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
1246 return TRACE_TYPE_HANDLED;
1247 }
1248
1249 /*
1250 * If the last output failed, there's a possibility we need
1251 * to print out the missing entry which would never go out.
1252 */
1253 if (data && data->failed) {
1254 field = &data->ent;
1255 iter->cpu = data->cpu;
1256 ret = print_graph_entry(field, s, iter, flags);
1257 if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
1258 per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
1259 ret = TRACE_TYPE_NO_CONSUME;
1260 }
1261 iter->cpu = cpu;
1262 return ret;
1263 }
1264
1265 switch (entry->type) {
1266 case TRACE_GRAPH_ENT: {
1267 /*
1268 * print_graph_entry() may consume the current event,
1269 * thus @field may become invalid, so we need to save it.
1270 * sizeof(struct ftrace_graph_ent_entry) is very small,
1271 * it can be safely saved at the stack.
1272 */
1273 struct ftrace_graph_ent_entry saved;
1274 trace_assign_type(field, entry);
1275 saved = *field;
1276 return print_graph_entry(&saved, s, iter, flags);
1277 }
1278 case TRACE_GRAPH_RET: {
1279 struct ftrace_graph_ret_entry *field;
1280 trace_assign_type(field, entry);
1281 return print_graph_return(&field->ret, s, entry, iter, flags);
1282 }
1283 case TRACE_STACK:
1284 case TRACE_FN:
1285 /* dont trace stack and functions as comments */
1286 return TRACE_TYPE_UNHANDLED;
1287
1288 default:
1289 return print_graph_comment(s, entry, iter, flags);
1290 }
1291
1292 return TRACE_TYPE_HANDLED;
1293 }
1294
1295 static enum print_line_t
1296 print_graph_function(struct trace_iterator *iter)
1297 {
1298 return print_graph_function_flags(iter, tracer_flags.val);
1299 }
1300
1301 static void print_lat_header(struct seq_file *s, u32 flags)
1302 {
1303 static const char spaces[] = " " /* 16 spaces */
1304 " " /* 4 spaces */
1305 " "; /* 17 spaces */
1306 int size = 0;
1307
1308 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1309 size += 16;
1310 if (flags & TRACE_GRAPH_PRINT_CPU)
1311 size += 4;
1312 if (flags & TRACE_GRAPH_PRINT_PROC)
1313 size += 17;
1314
1315 seq_printf(s, "#%.*s _-----=> irqs-off \n", size, spaces);
1316 seq_printf(s, "#%.*s / _----=> need-resched \n", size, spaces);
1317 seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
1318 seq_printf(s, "#%.*s|| / _--=> preempt-depth \n", size, spaces);
1319 seq_printf(s, "#%.*s||| / \n", size, spaces);
1320 }
1321
1322 static void __print_graph_headers_flags(struct seq_file *s, u32 flags)
1323 {
1324 int lat = trace_flags & TRACE_ITER_LATENCY_FMT;
1325
1326 if (lat)
1327 print_lat_header(s, flags);
1328
1329 /* 1st line */
1330 seq_printf(s, "#");
1331 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1332 seq_printf(s, " TIME ");
1333 if (flags & TRACE_GRAPH_PRINT_CPU)
1334 seq_printf(s, " CPU");
1335 if (flags & TRACE_GRAPH_PRINT_PROC)
1336 seq_printf(s, " TASK/PID ");
1337 if (lat)
1338 seq_printf(s, "||||");
1339 if (flags & TRACE_GRAPH_PRINT_DURATION)
1340 seq_printf(s, " DURATION ");
1341 seq_printf(s, " FUNCTION CALLS\n");
1342
1343 /* 2nd line */
1344 seq_printf(s, "#");
1345 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1346 seq_printf(s, " | ");
1347 if (flags & TRACE_GRAPH_PRINT_CPU)
1348 seq_printf(s, " | ");
1349 if (flags & TRACE_GRAPH_PRINT_PROC)
1350 seq_printf(s, " | | ");
1351 if (lat)
1352 seq_printf(s, "||||");
1353 if (flags & TRACE_GRAPH_PRINT_DURATION)
1354 seq_printf(s, " | | ");
1355 seq_printf(s, " | | | |\n");
1356 }
1357
1358 void print_graph_headers(struct seq_file *s)
1359 {
1360 print_graph_headers_flags(s, tracer_flags.val);
1361 }
1362
1363 void print_graph_headers_flags(struct seq_file *s, u32 flags)
1364 {
1365 struct trace_iterator *iter = s->private;
1366
1367 if (flags & TRACE_GRAPH_PRINT_FLAT) {
1368 trace_default_header(s);
1369 return;
1370 }
1371
1372 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
1373 return;
1374
1375 if (trace_flags & TRACE_ITER_LATENCY_FMT) {
1376 /* print nothing if the buffers are empty */
1377 if (trace_empty(iter))
1378 return;
1379
1380 print_trace_header(s, iter);
1381 }
1382
1383 __print_graph_headers_flags(s, flags);
1384 }
1385
1386 void graph_trace_open(struct trace_iterator *iter)
1387 {
1388 /* pid and depth on the last trace processed */
1389 struct fgraph_data *data;
1390 int cpu;
1391
1392 iter->private = NULL;
1393
1394 data = kzalloc(sizeof(*data), GFP_KERNEL);
1395 if (!data)
1396 goto out_err;
1397
1398 data->cpu_data = alloc_percpu(struct fgraph_cpu_data);
1399 if (!data->cpu_data)
1400 goto out_err_free;
1401
1402 for_each_possible_cpu(cpu) {
1403 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
1404 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
1405 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
1406 int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1407
1408 *pid = -1;
1409 *depth = 0;
1410 *ignore = 0;
1411 *depth_irq = -1;
1412 }
1413
1414 iter->private = data;
1415
1416 return;
1417
1418 out_err_free:
1419 kfree(data);
1420 out_err:
1421 pr_warning("function graph tracer: not enough memory\n");
1422 }
1423
1424 void graph_trace_close(struct trace_iterator *iter)
1425 {
1426 struct fgraph_data *data = iter->private;
1427
1428 if (data) {
1429 free_percpu(data->cpu_data);
1430 kfree(data);
1431 }
1432 }
1433
1434 static int func_graph_set_flag(u32 old_flags, u32 bit, int set)
1435 {
1436 if (bit == TRACE_GRAPH_PRINT_IRQS)
1437 ftrace_graph_skip_irqs = !set;
1438
1439 return 0;
1440 }
1441
1442 static struct tracer graph_trace __read_mostly = {
1443 .name = "function_graph",
1444 .open = graph_trace_open,
1445 .pipe_open = graph_trace_open,
1446 .close = graph_trace_close,
1447 .pipe_close = graph_trace_close,
1448 .wait_pipe = poll_wait_pipe,
1449 .init = graph_trace_init,
1450 .reset = graph_trace_reset,
1451 .print_line = print_graph_function,
1452 .print_header = print_graph_headers,
1453 .flags = &tracer_flags,
1454 .set_flag = func_graph_set_flag,
1455 #ifdef CONFIG_FTRACE_SELFTEST
1456 .selftest = trace_selftest_startup_function_graph,
1457 #endif
1458 };
1459
1460
1461 static ssize_t
1462 graph_depth_write(struct file *filp, const char __user *ubuf, size_t cnt,
1463 loff_t *ppos)
1464 {
1465 unsigned long val;
1466 int ret;
1467
1468 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1469 if (ret)
1470 return ret;
1471
1472 max_depth = val;
1473
1474 *ppos += cnt;
1475
1476 return cnt;
1477 }
1478
1479 static ssize_t
1480 graph_depth_read(struct file *filp, char __user *ubuf, size_t cnt,
1481 loff_t *ppos)
1482 {
1483 char buf[15]; /* More than enough to hold UINT_MAX + "\n"*/
1484 int n;
1485
1486 n = sprintf(buf, "%d\n", max_depth);
1487
1488 return simple_read_from_buffer(ubuf, cnt, ppos, buf, n);
1489 }
1490
1491 static const struct file_operations graph_depth_fops = {
1492 .open = tracing_open_generic,
1493 .write = graph_depth_write,
1494 .read = graph_depth_read,
1495 .llseek = generic_file_llseek,
1496 };
1497
1498 static __init int init_graph_debugfs(void)
1499 {
1500 struct dentry *d_tracer;
1501
1502 d_tracer = tracing_init_dentry();
1503 if (!d_tracer)
1504 return 0;
1505
1506 trace_create_file("max_graph_depth", 0644, d_tracer,
1507 NULL, &graph_depth_fops);
1508
1509 return 0;
1510 }
1511 fs_initcall(init_graph_debugfs);
1512
1513 static __init int init_graph_trace(void)
1514 {
1515 max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);
1516
1517 return register_tracer(&graph_trace);
1518 }
1519
1520 core_initcall(init_graph_trace);
kernel source for telekom puls (alcatel/mediatek)