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ftrace-graph: Remove dependency of ftrace_stop() from ftrace_graph_stop()
[deliverable/linux.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 static bool kill_ftrace_graph;
19
20 /**
21 * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called
22 *
23 * ftrace_graph_stop() is called when a severe error is detected in
24 * the function graph tracing. This function is called by the critical
25 * paths of function graph to keep those paths from doing any more harm.
26 */
27 bool ftrace_graph_is_dead(void)
28 {
29 return kill_ftrace_graph;
30 }
31
32 /**
33 * ftrace_graph_stop - set to permanently disable function graph tracincg
34 *
35 * In case of an error int function graph tracing, this is called
36 * to try to keep function graph tracing from causing any more harm.
37 * Usually this is pretty severe and this is called to try to at least
38 * get a warning out to the user.
39 */
40 void ftrace_graph_stop(void)
41 {
42 kill_ftrace_graph = true;
43 /*
44 * ftrace_stop() will be removed when all archs are updated to
45 * use ftrace_graph_is_dead()
46 */
47 ftrace_stop();
48 }
49
50 /* When set, irq functions will be ignored */
51 static int ftrace_graph_skip_irqs;
52
53 struct fgraph_cpu_data {
54 pid_t last_pid;
55 int depth;
56 int depth_irq;
57 int ignore;
58 unsigned long enter_funcs[FTRACE_RETFUNC_DEPTH];
59 };
60
61 struct fgraph_data {
62 struct fgraph_cpu_data __percpu *cpu_data;
63
64 /* Place to preserve last processed entry. */
65 struct ftrace_graph_ent_entry ent;
66 struct ftrace_graph_ret_entry ret;
67 int failed;
68 int cpu;
69 };
70
71 #define TRACE_GRAPH_INDENT 2
72
73 static unsigned int max_depth;
74
75 static struct tracer_opt trace_opts[] = {
76 /* Display overruns? (for self-debug purpose) */
77 { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
78 /* Display CPU ? */
79 { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
80 /* Display Overhead ? */
81 { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
82 /* Display proc name/pid */
83 { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
84 /* Display duration of execution */
85 { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
86 /* Display absolute time of an entry */
87 { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
88 /* Display interrupts */
89 { TRACER_OPT(funcgraph-irqs, TRACE_GRAPH_PRINT_IRQS) },
90 /* Display function name after trailing } */
91 { TRACER_OPT(funcgraph-tail, TRACE_GRAPH_PRINT_TAIL) },
92 { } /* Empty entry */
93 };
94
95 static struct tracer_flags tracer_flags = {
96 /* Don't display overruns, proc, or tail by default */
97 .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
98 TRACE_GRAPH_PRINT_DURATION | TRACE_GRAPH_PRINT_IRQS,
99 .opts = trace_opts
100 };
101
102 static struct trace_array *graph_array;
103
104 /*
105 * DURATION column is being also used to display IRQ signs,
106 * following values are used by print_graph_irq and others
107 * to fill in space into DURATION column.
108 */
109 enum {
110 FLAGS_FILL_FULL = 1 << TRACE_GRAPH_PRINT_FILL_SHIFT,
111 FLAGS_FILL_START = 2 << TRACE_GRAPH_PRINT_FILL_SHIFT,
112 FLAGS_FILL_END = 3 << TRACE_GRAPH_PRINT_FILL_SHIFT,
113 };
114
115 static enum print_line_t
116 print_graph_duration(unsigned long long duration, struct trace_seq *s,
117 u32 flags);
118
119 /* Add a function return address to the trace stack on thread info.*/
120 int
121 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
122 unsigned long frame_pointer)
123 {
124 unsigned long long calltime;
125 int index;
126
127 if (unlikely(ftrace_graph_is_dead()))
128 return -EBUSY;
129
130 if (!current->ret_stack)
131 return -EBUSY;
132
133 /*
134 * We must make sure the ret_stack is tested before we read
135 * anything else.
136 */
137 smp_rmb();
138
139 /* The return trace stack is full */
140 if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
141 atomic_inc(&current->trace_overrun);
142 return -EBUSY;
143 }
144
145 /*
146 * The curr_ret_stack is an index to ftrace return stack of
147 * current task. Its value should be in [0, FTRACE_RETFUNC_
148 * DEPTH) when the function graph tracer is used. To support
149 * filtering out specific functions, it makes the index
150 * negative by subtracting huge value (FTRACE_NOTRACE_DEPTH)
151 * so when it sees a negative index the ftrace will ignore
152 * the record. And the index gets recovered when returning
153 * from the filtered function by adding the FTRACE_NOTRACE_
154 * DEPTH and then it'll continue to record functions normally.
155 *
156 * The curr_ret_stack is initialized to -1 and get increased
157 * in this function. So it can be less than -1 only if it was
158 * filtered out via ftrace_graph_notrace_addr() which can be
159 * set from set_graph_notrace file in debugfs by user.
160 */
161 if (current->curr_ret_stack < -1)
162 return -EBUSY;
163
164 calltime = trace_clock_local();
165
166 index = ++current->curr_ret_stack;
167 if (ftrace_graph_notrace_addr(func))
168 current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH;
169 barrier();
170 current->ret_stack[index].ret = ret;
171 current->ret_stack[index].func = func;
172 current->ret_stack[index].calltime = calltime;
173 current->ret_stack[index].subtime = 0;
174 current->ret_stack[index].fp = frame_pointer;
175 *depth = current->curr_ret_stack;
176
177 return 0;
178 }
179
180 /* Retrieve a function return address to the trace stack on thread info.*/
181 static void
182 ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
183 unsigned long frame_pointer)
184 {
185 int index;
186
187 index = current->curr_ret_stack;
188
189 /*
190 * A negative index here means that it's just returned from a
191 * notrace'd function. Recover index to get an original
192 * return address. See ftrace_push_return_trace().
193 *
194 * TODO: Need to check whether the stack gets corrupted.
195 */
196 if (index < 0)
197 index += FTRACE_NOTRACE_DEPTH;
198
199 if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) {
200 ftrace_graph_stop();
201 WARN_ON(1);
202 /* Might as well panic, otherwise we have no where to go */
203 *ret = (unsigned long)panic;
204 return;
205 }
206
207 #if defined(CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST) && !defined(CC_USING_FENTRY)
208 /*
209 * The arch may choose to record the frame pointer used
210 * and check it here to make sure that it is what we expect it
211 * to be. If gcc does not set the place holder of the return
212 * address in the frame pointer, and does a copy instead, then
213 * the function graph trace will fail. This test detects this
214 * case.
215 *
216 * Currently, x86_32 with optimize for size (-Os) makes the latest
217 * gcc do the above.
218 *
219 * Note, -mfentry does not use frame pointers, and this test
220 * is not needed if CC_USING_FENTRY is set.
221 */
222 if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
223 ftrace_graph_stop();
224 WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
225 " from func %ps return to %lx\n",
226 current->ret_stack[index].fp,
227 frame_pointer,
228 (void *)current->ret_stack[index].func,
229 current->ret_stack[index].ret);
230 *ret = (unsigned long)panic;
231 return;
232 }
233 #endif
234
235 *ret = current->ret_stack[index].ret;
236 trace->func = current->ret_stack[index].func;
237 trace->calltime = current->ret_stack[index].calltime;
238 trace->overrun = atomic_read(&current->trace_overrun);
239 trace->depth = index;
240 }
241
242 /*
243 * Send the trace to the ring-buffer.
244 * @return the original return address.
245 */
246 unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
247 {
248 struct ftrace_graph_ret trace;
249 unsigned long ret;
250
251 ftrace_pop_return_trace(&trace, &ret, frame_pointer);
252 trace.rettime = trace_clock_local();
253 barrier();
254 current->curr_ret_stack--;
255 /*
256 * The curr_ret_stack can be less than -1 only if it was
257 * filtered out and it's about to return from the function.
258 * Recover the index and continue to trace normal functions.
259 */
260 if (current->curr_ret_stack < -1) {
261 current->curr_ret_stack += FTRACE_NOTRACE_DEPTH;
262 return ret;
263 }
264
265 /*
266 * The trace should run after decrementing the ret counter
267 * in case an interrupt were to come in. We don't want to
268 * lose the interrupt if max_depth is set.
269 */
270 ftrace_graph_return(&trace);
271
272 if (unlikely(!ret)) {
273 ftrace_graph_stop();
274 WARN_ON(1);
275 /* Might as well panic. What else to do? */
276 ret = (unsigned long)panic;
277 }
278
279 return ret;
280 }
281
282 int __trace_graph_entry(struct trace_array *tr,
283 struct ftrace_graph_ent *trace,
284 unsigned long flags,
285 int pc)
286 {
287 struct ftrace_event_call *call = &event_funcgraph_entry;
288 struct ring_buffer_event *event;
289 struct ring_buffer *buffer = tr->trace_buffer.buffer;
290 struct ftrace_graph_ent_entry *entry;
291
292 if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
293 return 0;
294
295 event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
296 sizeof(*entry), flags, pc);
297 if (!event)
298 return 0;
299 entry = ring_buffer_event_data(event);
300 entry->graph_ent = *trace;
301 if (!call_filter_check_discard(call, entry, buffer, event))
302 __buffer_unlock_commit(buffer, event);
303
304 return 1;
305 }
306
307 static inline int ftrace_graph_ignore_irqs(void)
308 {
309 if (!ftrace_graph_skip_irqs || trace_recursion_test(TRACE_IRQ_BIT))
310 return 0;
311
312 return in_irq();
313 }
314
315 int trace_graph_entry(struct ftrace_graph_ent *trace)
316 {
317 struct trace_array *tr = graph_array;
318 struct trace_array_cpu *data;
319 unsigned long flags;
320 long disabled;
321 int ret;
322 int cpu;
323 int pc;
324
325 if (!ftrace_trace_task(current))
326 return 0;
327
328 /* trace it when it is-nested-in or is a function enabled. */
329 if ((!(trace->depth || ftrace_graph_addr(trace->func)) ||
330 ftrace_graph_ignore_irqs()) || (trace->depth < 0) ||
331 (max_depth && trace->depth >= max_depth))
332 return 0;
333
334 /*
335 * Do not trace a function if it's filtered by set_graph_notrace.
336 * Make the index of ret stack negative to indicate that it should
337 * ignore further functions. But it needs its own ret stack entry
338 * to recover the original index in order to continue tracing after
339 * returning from the function.
340 */
341 if (ftrace_graph_notrace_addr(trace->func))
342 return 1;
343
344 local_irq_save(flags);
345 cpu = raw_smp_processor_id();
346 data = per_cpu_ptr(tr->trace_buffer.data, cpu);
347 disabled = atomic_inc_return(&data->disabled);
348 if (likely(disabled == 1)) {
349 pc = preempt_count();
350 ret = __trace_graph_entry(tr, trace, flags, pc);
351 } else {
352 ret = 0;
353 }
354
355 atomic_dec(&data->disabled);
356 local_irq_restore(flags);
357
358 return ret;
359 }
360
361 int trace_graph_thresh_entry(struct ftrace_graph_ent *trace)
362 {
363 if (tracing_thresh)
364 return 1;
365 else
366 return trace_graph_entry(trace);
367 }
368
369 static void
370 __trace_graph_function(struct trace_array *tr,
371 unsigned long ip, unsigned long flags, int pc)
372 {
373 u64 time = trace_clock_local();
374 struct ftrace_graph_ent ent = {
375 .func = ip,
376 .depth = 0,
377 };
378 struct ftrace_graph_ret ret = {
379 .func = ip,
380 .depth = 0,
381 .calltime = time,
382 .rettime = time,
383 };
384
385 __trace_graph_entry(tr, &ent, flags, pc);
386 __trace_graph_return(tr, &ret, flags, pc);
387 }
388
389 void
390 trace_graph_function(struct trace_array *tr,
391 unsigned long ip, unsigned long parent_ip,
392 unsigned long flags, int pc)
393 {
394 __trace_graph_function(tr, ip, flags, pc);
395 }
396
397 void __trace_graph_return(struct trace_array *tr,
398 struct ftrace_graph_ret *trace,
399 unsigned long flags,
400 int pc)
401 {
402 struct ftrace_event_call *call = &event_funcgraph_exit;
403 struct ring_buffer_event *event;
404 struct ring_buffer *buffer = tr->trace_buffer.buffer;
405 struct ftrace_graph_ret_entry *entry;
406
407 if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
408 return;
409
410 event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
411 sizeof(*entry), flags, pc);
412 if (!event)
413 return;
414 entry = ring_buffer_event_data(event);
415 entry->ret = *trace;
416 if (!call_filter_check_discard(call, entry, buffer, event))
417 __buffer_unlock_commit(buffer, event);
418 }
419
420 void trace_graph_return(struct ftrace_graph_ret *trace)
421 {
422 struct trace_array *tr = graph_array;
423 struct trace_array_cpu *data;
424 unsigned long flags;
425 long disabled;
426 int cpu;
427 int pc;
428
429 local_irq_save(flags);
430 cpu = raw_smp_processor_id();
431 data = per_cpu_ptr(tr->trace_buffer.data, cpu);
432 disabled = atomic_inc_return(&data->disabled);
433 if (likely(disabled == 1)) {
434 pc = preempt_count();
435 __trace_graph_return(tr, trace, flags, pc);
436 }
437 atomic_dec(&data->disabled);
438 local_irq_restore(flags);
439 }
440
441 void set_graph_array(struct trace_array *tr)
442 {
443 graph_array = tr;
444
445 /* Make graph_array visible before we start tracing */
446
447 smp_mb();
448 }
449
450 void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
451 {
452 if (tracing_thresh &&
453 (trace->rettime - trace->calltime < tracing_thresh))
454 return;
455 else
456 trace_graph_return(trace);
457 }
458
459 static int graph_trace_init(struct trace_array *tr)
460 {
461 int ret;
462
463 set_graph_array(tr);
464 if (tracing_thresh)
465 ret = register_ftrace_graph(&trace_graph_thresh_return,
466 &trace_graph_thresh_entry);
467 else
468 ret = register_ftrace_graph(&trace_graph_return,
469 &trace_graph_entry);
470 if (ret)
471 return ret;
472 tracing_start_cmdline_record();
473
474 return 0;
475 }
476
477 static void graph_trace_reset(struct trace_array *tr)
478 {
479 tracing_stop_cmdline_record();
480 unregister_ftrace_graph();
481 }
482
483 static int max_bytes_for_cpu;
484
485 static enum print_line_t
486 print_graph_cpu(struct trace_seq *s, int cpu)
487 {
488 int ret;
489
490 /*
491 * Start with a space character - to make it stand out
492 * to the right a bit when trace output is pasted into
493 * email:
494 */
495 ret = trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
496 if (!ret)
497 return TRACE_TYPE_PARTIAL_LINE;
498
499 return TRACE_TYPE_HANDLED;
500 }
501
502 #define TRACE_GRAPH_PROCINFO_LENGTH 14
503
504 static enum print_line_t
505 print_graph_proc(struct trace_seq *s, pid_t pid)
506 {
507 char comm[TASK_COMM_LEN];
508 /* sign + log10(MAX_INT) + '\0' */
509 char pid_str[11];
510 int spaces = 0;
511 int ret;
512 int len;
513 int i;
514
515 trace_find_cmdline(pid, comm);
516 comm[7] = '\0';
517 sprintf(pid_str, "%d", pid);
518
519 /* 1 stands for the "-" character */
520 len = strlen(comm) + strlen(pid_str) + 1;
521
522 if (len < TRACE_GRAPH_PROCINFO_LENGTH)
523 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
524
525 /* First spaces to align center */
526 for (i = 0; i < spaces / 2; i++) {
527 ret = trace_seq_putc(s, ' ');
528 if (!ret)
529 return TRACE_TYPE_PARTIAL_LINE;
530 }
531
532 ret = trace_seq_printf(s, "%s-%s", comm, pid_str);
533 if (!ret)
534 return TRACE_TYPE_PARTIAL_LINE;
535
536 /* Last spaces to align center */
537 for (i = 0; i < spaces - (spaces / 2); i++) {
538 ret = trace_seq_putc(s, ' ');
539 if (!ret)
540 return TRACE_TYPE_PARTIAL_LINE;
541 }
542 return TRACE_TYPE_HANDLED;
543 }
544
545
546 static enum print_line_t
547 print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
548 {
549 if (!trace_seq_putc(s, ' '))
550 return 0;
551
552 return trace_print_lat_fmt(s, entry);
553 }
554
555 /* If the pid changed since the last trace, output this event */
556 static enum print_line_t
557 verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
558 {
559 pid_t prev_pid;
560 pid_t *last_pid;
561 int ret;
562
563 if (!data)
564 return TRACE_TYPE_HANDLED;
565
566 last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
567
568 if (*last_pid == pid)
569 return TRACE_TYPE_HANDLED;
570
571 prev_pid = *last_pid;
572 *last_pid = pid;
573
574 if (prev_pid == -1)
575 return TRACE_TYPE_HANDLED;
576 /*
577 * Context-switch trace line:
578
579 ------------------------------------------
580 | 1) migration/0--1 => sshd-1755
581 ------------------------------------------
582
583 */
584 ret = trace_seq_puts(s,
585 " ------------------------------------------\n");
586 if (!ret)
587 return TRACE_TYPE_PARTIAL_LINE;
588
589 ret = print_graph_cpu(s, cpu);
590 if (ret == TRACE_TYPE_PARTIAL_LINE)
591 return TRACE_TYPE_PARTIAL_LINE;
592
593 ret = print_graph_proc(s, prev_pid);
594 if (ret == TRACE_TYPE_PARTIAL_LINE)
595 return TRACE_TYPE_PARTIAL_LINE;
596
597 ret = trace_seq_puts(s, " => ");
598 if (!ret)
599 return TRACE_TYPE_PARTIAL_LINE;
600
601 ret = print_graph_proc(s, pid);
602 if (ret == TRACE_TYPE_PARTIAL_LINE)
603 return TRACE_TYPE_PARTIAL_LINE;
604
605 ret = trace_seq_puts(s,
606 "\n ------------------------------------------\n\n");
607 if (!ret)
608 return TRACE_TYPE_PARTIAL_LINE;
609
610 return TRACE_TYPE_HANDLED;
611 }
612
613 static struct ftrace_graph_ret_entry *
614 get_return_for_leaf(struct trace_iterator *iter,
615 struct ftrace_graph_ent_entry *curr)
616 {
617 struct fgraph_data *data = iter->private;
618 struct ring_buffer_iter *ring_iter = NULL;
619 struct ring_buffer_event *event;
620 struct ftrace_graph_ret_entry *next;
621
622 /*
623 * If the previous output failed to write to the seq buffer,
624 * then we just reuse the data from before.
625 */
626 if (data && data->failed) {
627 curr = &data->ent;
628 next = &data->ret;
629 } else {
630
631 ring_iter = trace_buffer_iter(iter, iter->cpu);
632
633 /* First peek to compare current entry and the next one */
634 if (ring_iter)
635 event = ring_buffer_iter_peek(ring_iter, NULL);
636 else {
637 /*
638 * We need to consume the current entry to see
639 * the next one.
640 */
641 ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu,
642 NULL, NULL);
643 event = ring_buffer_peek(iter->trace_buffer->buffer, iter->cpu,
644 NULL, NULL);
645 }
646
647 if (!event)
648 return NULL;
649
650 next = ring_buffer_event_data(event);
651
652 if (data) {
653 /*
654 * Save current and next entries for later reference
655 * if the output fails.
656 */
657 data->ent = *curr;
658 /*
659 * If the next event is not a return type, then
660 * we only care about what type it is. Otherwise we can
661 * safely copy the entire event.
662 */
663 if (next->ent.type == TRACE_GRAPH_RET)
664 data->ret = *next;
665 else
666 data->ret.ent.type = next->ent.type;
667 }
668 }
669
670 if (next->ent.type != TRACE_GRAPH_RET)
671 return NULL;
672
673 if (curr->ent.pid != next->ent.pid ||
674 curr->graph_ent.func != next->ret.func)
675 return NULL;
676
677 /* this is a leaf, now advance the iterator */
678 if (ring_iter)
679 ring_buffer_read(ring_iter, NULL);
680
681 return next;
682 }
683
684 static int print_graph_abs_time(u64 t, struct trace_seq *s)
685 {
686 unsigned long usecs_rem;
687
688 usecs_rem = do_div(t, NSEC_PER_SEC);
689 usecs_rem /= 1000;
690
691 return trace_seq_printf(s, "%5lu.%06lu | ",
692 (unsigned long)t, usecs_rem);
693 }
694
695 static enum print_line_t
696 print_graph_irq(struct trace_iterator *iter, unsigned long addr,
697 enum trace_type type, int cpu, pid_t pid, u32 flags)
698 {
699 int ret;
700 struct trace_seq *s = &iter->seq;
701
702 if (addr < (unsigned long)__irqentry_text_start ||
703 addr >= (unsigned long)__irqentry_text_end)
704 return TRACE_TYPE_UNHANDLED;
705
706 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
707 /* Absolute time */
708 if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {
709 ret = print_graph_abs_time(iter->ts, s);
710 if (!ret)
711 return TRACE_TYPE_PARTIAL_LINE;
712 }
713
714 /* Cpu */
715 if (flags & TRACE_GRAPH_PRINT_CPU) {
716 ret = print_graph_cpu(s, cpu);
717 if (ret == TRACE_TYPE_PARTIAL_LINE)
718 return TRACE_TYPE_PARTIAL_LINE;
719 }
720
721 /* Proc */
722 if (flags & TRACE_GRAPH_PRINT_PROC) {
723 ret = print_graph_proc(s, pid);
724 if (ret == TRACE_TYPE_PARTIAL_LINE)
725 return TRACE_TYPE_PARTIAL_LINE;
726 ret = trace_seq_puts(s, " | ");
727 if (!ret)
728 return TRACE_TYPE_PARTIAL_LINE;
729 }
730 }
731
732 /* No overhead */
733 ret = print_graph_duration(0, s, flags | FLAGS_FILL_START);
734 if (ret != TRACE_TYPE_HANDLED)
735 return ret;
736
737 if (type == TRACE_GRAPH_ENT)
738 ret = trace_seq_puts(s, "==========>");
739 else
740 ret = trace_seq_puts(s, "<==========");
741
742 if (!ret)
743 return TRACE_TYPE_PARTIAL_LINE;
744
745 ret = print_graph_duration(0, s, flags | FLAGS_FILL_END);
746 if (ret != TRACE_TYPE_HANDLED)
747 return ret;
748
749 ret = trace_seq_putc(s, '\n');
750
751 if (!ret)
752 return TRACE_TYPE_PARTIAL_LINE;
753 return TRACE_TYPE_HANDLED;
754 }
755
756 enum print_line_t
757 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
758 {
759 unsigned long nsecs_rem = do_div(duration, 1000);
760 /* log10(ULONG_MAX) + '\0' */
761 char msecs_str[21];
762 char nsecs_str[5];
763 int ret, len;
764 int i;
765
766 sprintf(msecs_str, "%lu", (unsigned long) duration);
767
768 /* Print msecs */
769 ret = trace_seq_printf(s, "%s", msecs_str);
770 if (!ret)
771 return TRACE_TYPE_PARTIAL_LINE;
772
773 len = strlen(msecs_str);
774
775 /* Print nsecs (we don't want to exceed 7 numbers) */
776 if (len < 7) {
777 size_t slen = min_t(size_t, sizeof(nsecs_str), 8UL - len);
778
779 snprintf(nsecs_str, slen, "%03lu", nsecs_rem);
780 ret = trace_seq_printf(s, ".%s", nsecs_str);
781 if (!ret)
782 return TRACE_TYPE_PARTIAL_LINE;
783 len += strlen(nsecs_str);
784 }
785
786 ret = trace_seq_puts(s, " us ");
787 if (!ret)
788 return TRACE_TYPE_PARTIAL_LINE;
789
790 /* Print remaining spaces to fit the row's width */
791 for (i = len; i < 7; i++) {
792 ret = trace_seq_putc(s, ' ');
793 if (!ret)
794 return TRACE_TYPE_PARTIAL_LINE;
795 }
796 return TRACE_TYPE_HANDLED;
797 }
798
799 static enum print_line_t
800 print_graph_duration(unsigned long long duration, struct trace_seq *s,
801 u32 flags)
802 {
803 int ret = -1;
804
805 if (!(flags & TRACE_GRAPH_PRINT_DURATION) ||
806 !(trace_flags & TRACE_ITER_CONTEXT_INFO))
807 return TRACE_TYPE_HANDLED;
808
809 /* No real adata, just filling the column with spaces */
810 switch (flags & TRACE_GRAPH_PRINT_FILL_MASK) {
811 case FLAGS_FILL_FULL:
812 ret = trace_seq_puts(s, " | ");
813 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
814 case FLAGS_FILL_START:
815 ret = trace_seq_puts(s, " ");
816 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
817 case FLAGS_FILL_END:
818 ret = trace_seq_puts(s, " |");
819 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
820 }
821
822 /* Signal a overhead of time execution to the output */
823 if (flags & TRACE_GRAPH_PRINT_OVERHEAD) {
824 /* Duration exceeded 100 msecs */
825 if (duration > 100000ULL)
826 ret = trace_seq_puts(s, "! ");
827 /* Duration exceeded 10 msecs */
828 else if (duration > 10000ULL)
829 ret = trace_seq_puts(s, "+ ");
830 }
831
832 /*
833 * The -1 means we either did not exceed the duration tresholds
834 * or we dont want to print out the overhead. Either way we need
835 * to fill out the space.
836 */
837 if (ret == -1)
838 ret = trace_seq_puts(s, " ");
839
840 /* Catching here any failure happenned above */
841 if (!ret)
842 return TRACE_TYPE_PARTIAL_LINE;
843
844 ret = trace_print_graph_duration(duration, s);
845 if (ret != TRACE_TYPE_HANDLED)
846 return ret;
847
848 ret = trace_seq_puts(s, "| ");
849 if (!ret)
850 return TRACE_TYPE_PARTIAL_LINE;
851
852 return TRACE_TYPE_HANDLED;
853 }
854
855 /* Case of a leaf function on its call entry */
856 static enum print_line_t
857 print_graph_entry_leaf(struct trace_iterator *iter,
858 struct ftrace_graph_ent_entry *entry,
859 struct ftrace_graph_ret_entry *ret_entry,
860 struct trace_seq *s, u32 flags)
861 {
862 struct fgraph_data *data = iter->private;
863 struct ftrace_graph_ret *graph_ret;
864 struct ftrace_graph_ent *call;
865 unsigned long long duration;
866 int ret;
867 int i;
868
869 graph_ret = &ret_entry->ret;
870 call = &entry->graph_ent;
871 duration = graph_ret->rettime - graph_ret->calltime;
872
873 if (data) {
874 struct fgraph_cpu_data *cpu_data;
875 int cpu = iter->cpu;
876
877 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
878
879 /*
880 * Comments display at + 1 to depth. Since
881 * this is a leaf function, keep the comments
882 * equal to this depth.
883 */
884 cpu_data->depth = call->depth - 1;
885
886 /* No need to keep this function around for this depth */
887 if (call->depth < FTRACE_RETFUNC_DEPTH)
888 cpu_data->enter_funcs[call->depth] = 0;
889 }
890
891 /* Overhead and duration */
892 ret = print_graph_duration(duration, s, flags);
893 if (ret == TRACE_TYPE_PARTIAL_LINE)
894 return TRACE_TYPE_PARTIAL_LINE;
895
896 /* Function */
897 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
898 ret = trace_seq_putc(s, ' ');
899 if (!ret)
900 return TRACE_TYPE_PARTIAL_LINE;
901 }
902
903 ret = trace_seq_printf(s, "%ps();\n", (void *)call->func);
904 if (!ret)
905 return TRACE_TYPE_PARTIAL_LINE;
906
907 return TRACE_TYPE_HANDLED;
908 }
909
910 static enum print_line_t
911 print_graph_entry_nested(struct trace_iterator *iter,
912 struct ftrace_graph_ent_entry *entry,
913 struct trace_seq *s, int cpu, u32 flags)
914 {
915 struct ftrace_graph_ent *call = &entry->graph_ent;
916 struct fgraph_data *data = iter->private;
917 int ret;
918 int i;
919
920 if (data) {
921 struct fgraph_cpu_data *cpu_data;
922 int cpu = iter->cpu;
923
924 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
925 cpu_data->depth = call->depth;
926
927 /* Save this function pointer to see if the exit matches */
928 if (call->depth < FTRACE_RETFUNC_DEPTH)
929 cpu_data->enter_funcs[call->depth] = call->func;
930 }
931
932 /* No time */
933 ret = print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
934 if (ret != TRACE_TYPE_HANDLED)
935 return ret;
936
937 /* Function */
938 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
939 ret = trace_seq_putc(s, ' ');
940 if (!ret)
941 return TRACE_TYPE_PARTIAL_LINE;
942 }
943
944 ret = trace_seq_printf(s, "%ps() {\n", (void *)call->func);
945 if (!ret)
946 return TRACE_TYPE_PARTIAL_LINE;
947
948 /*
949 * we already consumed the current entry to check the next one
950 * and see if this is a leaf.
951 */
952 return TRACE_TYPE_NO_CONSUME;
953 }
954
955 static enum print_line_t
956 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
957 int type, unsigned long addr, u32 flags)
958 {
959 struct fgraph_data *data = iter->private;
960 struct trace_entry *ent = iter->ent;
961 int cpu = iter->cpu;
962 int ret;
963
964 /* Pid */
965 if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)
966 return TRACE_TYPE_PARTIAL_LINE;
967
968 if (type) {
969 /* Interrupt */
970 ret = print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
971 if (ret == TRACE_TYPE_PARTIAL_LINE)
972 return TRACE_TYPE_PARTIAL_LINE;
973 }
974
975 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
976 return 0;
977
978 /* Absolute time */
979 if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {
980 ret = print_graph_abs_time(iter->ts, s);
981 if (!ret)
982 return TRACE_TYPE_PARTIAL_LINE;
983 }
984
985 /* Cpu */
986 if (flags & TRACE_GRAPH_PRINT_CPU) {
987 ret = print_graph_cpu(s, cpu);
988 if (ret == TRACE_TYPE_PARTIAL_LINE)
989 return TRACE_TYPE_PARTIAL_LINE;
990 }
991
992 /* Proc */
993 if (flags & TRACE_GRAPH_PRINT_PROC) {
994 ret = print_graph_proc(s, ent->pid);
995 if (ret == TRACE_TYPE_PARTIAL_LINE)
996 return TRACE_TYPE_PARTIAL_LINE;
997
998 ret = trace_seq_puts(s, " | ");
999 if (!ret)
1000 return TRACE_TYPE_PARTIAL_LINE;
1001 }
1002
1003 /* Latency format */
1004 if (trace_flags & TRACE_ITER_LATENCY_FMT) {
1005 ret = print_graph_lat_fmt(s, ent);
1006 if (ret == TRACE_TYPE_PARTIAL_LINE)
1007 return TRACE_TYPE_PARTIAL_LINE;
1008 }
1009
1010 return 0;
1011 }
1012
1013 /*
1014 * Entry check for irq code
1015 *
1016 * returns 1 if
1017 * - we are inside irq code
1018 * - we just entered irq code
1019 *
1020 * retunns 0 if
1021 * - funcgraph-interrupts option is set
1022 * - we are not inside irq code
1023 */
1024 static int
1025 check_irq_entry(struct trace_iterator *iter, u32 flags,
1026 unsigned long addr, int depth)
1027 {
1028 int cpu = iter->cpu;
1029 int *depth_irq;
1030 struct fgraph_data *data = iter->private;
1031
1032 /*
1033 * If we are either displaying irqs, or we got called as
1034 * a graph event and private data does not exist,
1035 * then we bypass the irq check.
1036 */
1037 if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
1038 (!data))
1039 return 0;
1040
1041 depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1042
1043 /*
1044 * We are inside the irq code
1045 */
1046 if (*depth_irq >= 0)
1047 return 1;
1048
1049 if ((addr < (unsigned long)__irqentry_text_start) ||
1050 (addr >= (unsigned long)__irqentry_text_end))
1051 return 0;
1052
1053 /*
1054 * We are entering irq code.
1055 */
1056 *depth_irq = depth;
1057 return 1;
1058 }
1059
1060 /*
1061 * Return check for irq code
1062 *
1063 * returns 1 if
1064 * - we are inside irq code
1065 * - we just left irq code
1066 *
1067 * returns 0 if
1068 * - funcgraph-interrupts option is set
1069 * - we are not inside irq code
1070 */
1071 static int
1072 check_irq_return(struct trace_iterator *iter, u32 flags, int depth)
1073 {
1074 int cpu = iter->cpu;
1075 int *depth_irq;
1076 struct fgraph_data *data = iter->private;
1077
1078 /*
1079 * If we are either displaying irqs, or we got called as
1080 * a graph event and private data does not exist,
1081 * then we bypass the irq check.
1082 */
1083 if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
1084 (!data))
1085 return 0;
1086
1087 depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1088
1089 /*
1090 * We are not inside the irq code.
1091 */
1092 if (*depth_irq == -1)
1093 return 0;
1094
1095 /*
1096 * We are inside the irq code, and this is returning entry.
1097 * Let's not trace it and clear the entry depth, since
1098 * we are out of irq code.
1099 *
1100 * This condition ensures that we 'leave the irq code' once
1101 * we are out of the entry depth. Thus protecting us from
1102 * the RETURN entry loss.
1103 */
1104 if (*depth_irq >= depth) {
1105 *depth_irq = -1;
1106 return 1;
1107 }
1108
1109 /*
1110 * We are inside the irq code, and this is not the entry.
1111 */
1112 return 1;
1113 }
1114
1115 static enum print_line_t
1116 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
1117 struct trace_iterator *iter, u32 flags)
1118 {
1119 struct fgraph_data *data = iter->private;
1120 struct ftrace_graph_ent *call = &field->graph_ent;
1121 struct ftrace_graph_ret_entry *leaf_ret;
1122 static enum print_line_t ret;
1123 int cpu = iter->cpu;
1124
1125 if (check_irq_entry(iter, flags, call->func, call->depth))
1126 return TRACE_TYPE_HANDLED;
1127
1128 if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags))
1129 return TRACE_TYPE_PARTIAL_LINE;
1130
1131 leaf_ret = get_return_for_leaf(iter, field);
1132 if (leaf_ret)
1133 ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags);
1134 else
1135 ret = print_graph_entry_nested(iter, field, s, cpu, flags);
1136
1137 if (data) {
1138 /*
1139 * If we failed to write our output, then we need to make
1140 * note of it. Because we already consumed our entry.
1141 */
1142 if (s->full) {
1143 data->failed = 1;
1144 data->cpu = cpu;
1145 } else
1146 data->failed = 0;
1147 }
1148
1149 return ret;
1150 }
1151
1152 static enum print_line_t
1153 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
1154 struct trace_entry *ent, struct trace_iterator *iter,
1155 u32 flags)
1156 {
1157 unsigned long long duration = trace->rettime - trace->calltime;
1158 struct fgraph_data *data = iter->private;
1159 pid_t pid = ent->pid;
1160 int cpu = iter->cpu;
1161 int func_match = 1;
1162 int ret;
1163 int i;
1164
1165 if (check_irq_return(iter, flags, trace->depth))
1166 return TRACE_TYPE_HANDLED;
1167
1168 if (data) {
1169 struct fgraph_cpu_data *cpu_data;
1170 int cpu = iter->cpu;
1171
1172 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
1173
1174 /*
1175 * Comments display at + 1 to depth. This is the
1176 * return from a function, we now want the comments
1177 * to display at the same level of the bracket.
1178 */
1179 cpu_data->depth = trace->depth - 1;
1180
1181 if (trace->depth < FTRACE_RETFUNC_DEPTH) {
1182 if (cpu_data->enter_funcs[trace->depth] != trace->func)
1183 func_match = 0;
1184 cpu_data->enter_funcs[trace->depth] = 0;
1185 }
1186 }
1187
1188 if (print_graph_prologue(iter, s, 0, 0, flags))
1189 return TRACE_TYPE_PARTIAL_LINE;
1190
1191 /* Overhead and duration */
1192 ret = print_graph_duration(duration, s, flags);
1193 if (ret == TRACE_TYPE_PARTIAL_LINE)
1194 return TRACE_TYPE_PARTIAL_LINE;
1195
1196 /* Closing brace */
1197 for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
1198 ret = trace_seq_putc(s, ' ');
1199 if (!ret)
1200 return TRACE_TYPE_PARTIAL_LINE;
1201 }
1202
1203 /*
1204 * If the return function does not have a matching entry,
1205 * then the entry was lost. Instead of just printing
1206 * the '}' and letting the user guess what function this
1207 * belongs to, write out the function name. Always do
1208 * that if the funcgraph-tail option is enabled.
1209 */
1210 if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL)) {
1211 ret = trace_seq_puts(s, "}\n");
1212 if (!ret)
1213 return TRACE_TYPE_PARTIAL_LINE;
1214 } else {
1215 ret = trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
1216 if (!ret)
1217 return TRACE_TYPE_PARTIAL_LINE;
1218 }
1219
1220 /* Overrun */
1221 if (flags & TRACE_GRAPH_PRINT_OVERRUN) {
1222 ret = trace_seq_printf(s, " (Overruns: %lu)\n",
1223 trace->overrun);
1224 if (!ret)
1225 return TRACE_TYPE_PARTIAL_LINE;
1226 }
1227
1228 ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
1229 cpu, pid, flags);
1230 if (ret == TRACE_TYPE_PARTIAL_LINE)
1231 return TRACE_TYPE_PARTIAL_LINE;
1232
1233 return TRACE_TYPE_HANDLED;
1234 }
1235
1236 static enum print_line_t
1237 print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
1238 struct trace_iterator *iter, u32 flags)
1239 {
1240 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1241 struct fgraph_data *data = iter->private;
1242 struct trace_event *event;
1243 int depth = 0;
1244 int ret;
1245 int i;
1246
1247 if (data)
1248 depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
1249
1250 if (print_graph_prologue(iter, s, 0, 0, flags))
1251 return TRACE_TYPE_PARTIAL_LINE;
1252
1253 /* No time */
1254 ret = print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
1255 if (ret != TRACE_TYPE_HANDLED)
1256 return ret;
1257
1258 /* Indentation */
1259 if (depth > 0)
1260 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) {
1261 ret = trace_seq_putc(s, ' ');
1262 if (!ret)
1263 return TRACE_TYPE_PARTIAL_LINE;
1264 }
1265
1266 /* The comment */
1267 ret = trace_seq_puts(s, "/* ");
1268 if (!ret)
1269 return TRACE_TYPE_PARTIAL_LINE;
1270
1271 switch (iter->ent->type) {
1272 case TRACE_BPRINT:
1273 ret = trace_print_bprintk_msg_only(iter);
1274 if (ret != TRACE_TYPE_HANDLED)
1275 return ret;
1276 break;
1277 case TRACE_PRINT:
1278 ret = trace_print_printk_msg_only(iter);
1279 if (ret != TRACE_TYPE_HANDLED)
1280 return ret;
1281 break;
1282 default:
1283 event = ftrace_find_event(ent->type);
1284 if (!event)
1285 return TRACE_TYPE_UNHANDLED;
1286
1287 ret = event->funcs->trace(iter, sym_flags, event);
1288 if (ret != TRACE_TYPE_HANDLED)
1289 return ret;
1290 }
1291
1292 /* Strip ending newline */
1293 if (s->buffer[s->len - 1] == '\n') {
1294 s->buffer[s->len - 1] = '\0';
1295 s->len--;
1296 }
1297
1298 ret = trace_seq_puts(s, " */\n");
1299 if (!ret)
1300 return TRACE_TYPE_PARTIAL_LINE;
1301
1302 return TRACE_TYPE_HANDLED;
1303 }
1304
1305
1306 enum print_line_t
1307 print_graph_function_flags(struct trace_iterator *iter, u32 flags)
1308 {
1309 struct ftrace_graph_ent_entry *field;
1310 struct fgraph_data *data = iter->private;
1311 struct trace_entry *entry = iter->ent;
1312 struct trace_seq *s = &iter->seq;
1313 int cpu = iter->cpu;
1314 int ret;
1315
1316 if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
1317 per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
1318 return TRACE_TYPE_HANDLED;
1319 }
1320
1321 /*
1322 * If the last output failed, there's a possibility we need
1323 * to print out the missing entry which would never go out.
1324 */
1325 if (data && data->failed) {
1326 field = &data->ent;
1327 iter->cpu = data->cpu;
1328 ret = print_graph_entry(field, s, iter, flags);
1329 if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
1330 per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
1331 ret = TRACE_TYPE_NO_CONSUME;
1332 }
1333 iter->cpu = cpu;
1334 return ret;
1335 }
1336
1337 switch (entry->type) {
1338 case TRACE_GRAPH_ENT: {
1339 /*
1340 * print_graph_entry() may consume the current event,
1341 * thus @field may become invalid, so we need to save it.
1342 * sizeof(struct ftrace_graph_ent_entry) is very small,
1343 * it can be safely saved at the stack.
1344 */
1345 struct ftrace_graph_ent_entry saved;
1346 trace_assign_type(field, entry);
1347 saved = *field;
1348 return print_graph_entry(&saved, s, iter, flags);
1349 }
1350 case TRACE_GRAPH_RET: {
1351 struct ftrace_graph_ret_entry *field;
1352 trace_assign_type(field, entry);
1353 return print_graph_return(&field->ret, s, entry, iter, flags);
1354 }
1355 case TRACE_STACK:
1356 case TRACE_FN:
1357 /* dont trace stack and functions as comments */
1358 return TRACE_TYPE_UNHANDLED;
1359
1360 default:
1361 return print_graph_comment(s, entry, iter, flags);
1362 }
1363
1364 return TRACE_TYPE_HANDLED;
1365 }
1366
1367 static enum print_line_t
1368 print_graph_function(struct trace_iterator *iter)
1369 {
1370 return print_graph_function_flags(iter, tracer_flags.val);
1371 }
1372
1373 static enum print_line_t
1374 print_graph_function_event(struct trace_iterator *iter, int flags,
1375 struct trace_event *event)
1376 {
1377 return print_graph_function(iter);
1378 }
1379
1380 static void print_lat_header(struct seq_file *s, u32 flags)
1381 {
1382 static const char spaces[] = " " /* 16 spaces */
1383 " " /* 4 spaces */
1384 " "; /* 17 spaces */
1385 int size = 0;
1386
1387 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1388 size += 16;
1389 if (flags & TRACE_GRAPH_PRINT_CPU)
1390 size += 4;
1391 if (flags & TRACE_GRAPH_PRINT_PROC)
1392 size += 17;
1393
1394 seq_printf(s, "#%.*s _-----=> irqs-off \n", size, spaces);
1395 seq_printf(s, "#%.*s / _----=> need-resched \n", size, spaces);
1396 seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
1397 seq_printf(s, "#%.*s|| / _--=> preempt-depth \n", size, spaces);
1398 seq_printf(s, "#%.*s||| / \n", size, spaces);
1399 }
1400
1401 static void __print_graph_headers_flags(struct seq_file *s, u32 flags)
1402 {
1403 int lat = trace_flags & TRACE_ITER_LATENCY_FMT;
1404
1405 if (lat)
1406 print_lat_header(s, flags);
1407
1408 /* 1st line */
1409 seq_printf(s, "#");
1410 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1411 seq_printf(s, " TIME ");
1412 if (flags & TRACE_GRAPH_PRINT_CPU)
1413 seq_printf(s, " CPU");
1414 if (flags & TRACE_GRAPH_PRINT_PROC)
1415 seq_printf(s, " TASK/PID ");
1416 if (lat)
1417 seq_printf(s, "||||");
1418 if (flags & TRACE_GRAPH_PRINT_DURATION)
1419 seq_printf(s, " DURATION ");
1420 seq_printf(s, " FUNCTION CALLS\n");
1421
1422 /* 2nd line */
1423 seq_printf(s, "#");
1424 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1425 seq_printf(s, " | ");
1426 if (flags & TRACE_GRAPH_PRINT_CPU)
1427 seq_printf(s, " | ");
1428 if (flags & TRACE_GRAPH_PRINT_PROC)
1429 seq_printf(s, " | | ");
1430 if (lat)
1431 seq_printf(s, "||||");
1432 if (flags & TRACE_GRAPH_PRINT_DURATION)
1433 seq_printf(s, " | | ");
1434 seq_printf(s, " | | | |\n");
1435 }
1436
1437 void print_graph_headers(struct seq_file *s)
1438 {
1439 print_graph_headers_flags(s, tracer_flags.val);
1440 }
1441
1442 void print_graph_headers_flags(struct seq_file *s, u32 flags)
1443 {
1444 struct trace_iterator *iter = s->private;
1445
1446 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
1447 return;
1448
1449 if (trace_flags & TRACE_ITER_LATENCY_FMT) {
1450 /* print nothing if the buffers are empty */
1451 if (trace_empty(iter))
1452 return;
1453
1454 print_trace_header(s, iter);
1455 }
1456
1457 __print_graph_headers_flags(s, flags);
1458 }
1459
1460 void graph_trace_open(struct trace_iterator *iter)
1461 {
1462 /* pid and depth on the last trace processed */
1463 struct fgraph_data *data;
1464 int cpu;
1465
1466 iter->private = NULL;
1467
1468 data = kzalloc(sizeof(*data), GFP_KERNEL);
1469 if (!data)
1470 goto out_err;
1471
1472 data->cpu_data = alloc_percpu(struct fgraph_cpu_data);
1473 if (!data->cpu_data)
1474 goto out_err_free;
1475
1476 for_each_possible_cpu(cpu) {
1477 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
1478 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
1479 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
1480 int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1481
1482 *pid = -1;
1483 *depth = 0;
1484 *ignore = 0;
1485 *depth_irq = -1;
1486 }
1487
1488 iter->private = data;
1489
1490 return;
1491
1492 out_err_free:
1493 kfree(data);
1494 out_err:
1495 pr_warning("function graph tracer: not enough memory\n");
1496 }
1497
1498 void graph_trace_close(struct trace_iterator *iter)
1499 {
1500 struct fgraph_data *data = iter->private;
1501
1502 if (data) {
1503 free_percpu(data->cpu_data);
1504 kfree(data);
1505 }
1506 }
1507
1508 static int
1509 func_graph_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1510 {
1511 if (bit == TRACE_GRAPH_PRINT_IRQS)
1512 ftrace_graph_skip_irqs = !set;
1513
1514 return 0;
1515 }
1516
1517 static struct trace_event_functions graph_functions = {
1518 .trace = print_graph_function_event,
1519 };
1520
1521 static struct trace_event graph_trace_entry_event = {
1522 .type = TRACE_GRAPH_ENT,
1523 .funcs = &graph_functions,
1524 };
1525
1526 static struct trace_event graph_trace_ret_event = {
1527 .type = TRACE_GRAPH_RET,
1528 .funcs = &graph_functions
1529 };
1530
1531 static struct tracer graph_trace __tracer_data = {
1532 .name = "function_graph",
1533 .open = graph_trace_open,
1534 .pipe_open = graph_trace_open,
1535 .close = graph_trace_close,
1536 .pipe_close = graph_trace_close,
1537 .init = graph_trace_init,
1538 .reset = graph_trace_reset,
1539 .print_line = print_graph_function,
1540 .print_header = print_graph_headers,
1541 .flags = &tracer_flags,
1542 .set_flag = func_graph_set_flag,
1543 #ifdef CONFIG_FTRACE_SELFTEST
1544 .selftest = trace_selftest_startup_function_graph,
1545 #endif
1546 };
1547
1548
1549 static ssize_t
1550 graph_depth_write(struct file *filp, const char __user *ubuf, size_t cnt,
1551 loff_t *ppos)
1552 {
1553 unsigned long val;
1554 int ret;
1555
1556 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1557 if (ret)
1558 return ret;
1559
1560 max_depth = val;
1561
1562 *ppos += cnt;
1563
1564 return cnt;
1565 }
1566
1567 static ssize_t
1568 graph_depth_read(struct file *filp, char __user *ubuf, size_t cnt,
1569 loff_t *ppos)
1570 {
1571 char buf[15]; /* More than enough to hold UINT_MAX + "\n"*/
1572 int n;
1573
1574 n = sprintf(buf, "%d\n", max_depth);
1575
1576 return simple_read_from_buffer(ubuf, cnt, ppos, buf, n);
1577 }
1578
1579 static const struct file_operations graph_depth_fops = {
1580 .open = tracing_open_generic,
1581 .write = graph_depth_write,
1582 .read = graph_depth_read,
1583 .llseek = generic_file_llseek,
1584 };
1585
1586 static __init int init_graph_debugfs(void)
1587 {
1588 struct dentry *d_tracer;
1589
1590 d_tracer = tracing_init_dentry();
1591 if (!d_tracer)
1592 return 0;
1593
1594 trace_create_file("max_graph_depth", 0644, d_tracer,
1595 NULL, &graph_depth_fops);
1596
1597 return 0;
1598 }
1599 fs_initcall(init_graph_debugfs);
1600
1601 static __init int init_graph_trace(void)
1602 {
1603 max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);
1604
1605 if (!register_ftrace_event(&graph_trace_entry_event)) {
1606 pr_warning("Warning: could not register graph trace events\n");
1607 return 1;
1608 }
1609
1610 if (!register_ftrace_event(&graph_trace_ret_event)) {
1611 pr_warning("Warning: could not register graph trace events\n");
1612 return 1;
1613 }
1614
1615 return register_tracer(&graph_trace);
1616 }
1617
1618 core_initcall(init_graph_trace);
Linux kernel - Deliverables
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