Loading...
1// SPDX-License-Identifier: GPL-2.0
2/*
3 *
4 * Function graph tracer.
5 * Copyright (c) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com>
6 * Mostly borrowed from function tracer which
7 * is Copyright (c) Steven Rostedt <srostedt@redhat.com>
8 *
9 */
10#include <linux/uaccess.h>
11#include <linux/ftrace.h>
12#include <linux/interrupt.h>
13#include <linux/slab.h>
14#include <linux/fs.h>
15
16#include "trace.h"
17#include "trace_output.h"
18
19/* When set, irq functions will be ignored */
20static int ftrace_graph_skip_irqs;
21
22struct fgraph_cpu_data {
23 pid_t last_pid;
24 int depth;
25 int depth_irq;
26 int ignore;
27 unsigned long enter_funcs[FTRACE_RETFUNC_DEPTH];
28};
29
30struct fgraph_data {
31 struct fgraph_cpu_data __percpu *cpu_data;
32
33 /* Place to preserve last processed entry. */
34 struct ftrace_graph_ent_entry ent;
35 struct ftrace_graph_ret_entry ret;
36 int failed;
37 int cpu;
38};
39
40#define TRACE_GRAPH_INDENT 2
41
42unsigned int fgraph_max_depth;
43
44static struct tracer_opt trace_opts[] = {
45 /* Display overruns? (for self-debug purpose) */
46 { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
47 /* Display CPU ? */
48 { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
49 /* Display Overhead ? */
50 { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
51 /* Display proc name/pid */
52 { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
53 /* Display duration of execution */
54 { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
55 /* Display absolute time of an entry */
56 { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
57 /* Display interrupts */
58 { TRACER_OPT(funcgraph-irqs, TRACE_GRAPH_PRINT_IRQS) },
59 /* Display function name after trailing } */
60 { TRACER_OPT(funcgraph-tail, TRACE_GRAPH_PRINT_TAIL) },
61 /* Include sleep time (scheduled out) between entry and return */
62 { TRACER_OPT(sleep-time, TRACE_GRAPH_SLEEP_TIME) },
63
64#ifdef CONFIG_FUNCTION_PROFILER
65 /* Include time within nested functions */
66 { TRACER_OPT(graph-time, TRACE_GRAPH_GRAPH_TIME) },
67#endif
68
69 { } /* Empty entry */
70};
71
72static struct tracer_flags tracer_flags = {
73 /* Don't display overruns, proc, or tail by default */
74 .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
75 TRACE_GRAPH_PRINT_DURATION | TRACE_GRAPH_PRINT_IRQS |
76 TRACE_GRAPH_SLEEP_TIME | TRACE_GRAPH_GRAPH_TIME,
77 .opts = trace_opts
78};
79
80static struct trace_array *graph_array;
81
82/*
83 * DURATION column is being also used to display IRQ signs,
84 * following values are used by print_graph_irq and others
85 * to fill in space into DURATION column.
86 */
87enum {
88 FLAGS_FILL_FULL = 1 << TRACE_GRAPH_PRINT_FILL_SHIFT,
89 FLAGS_FILL_START = 2 << TRACE_GRAPH_PRINT_FILL_SHIFT,
90 FLAGS_FILL_END = 3 << TRACE_GRAPH_PRINT_FILL_SHIFT,
91};
92
93static void
94print_graph_duration(struct trace_array *tr, unsigned long long duration,
95 struct trace_seq *s, u32 flags);
96
97int __trace_graph_entry(struct trace_array *tr,
98 struct ftrace_graph_ent *trace,
99 unsigned int trace_ctx)
100{
101 struct trace_event_call *call = &event_funcgraph_entry;
102 struct ring_buffer_event *event;
103 struct trace_buffer *buffer = tr->array_buffer.buffer;
104 struct ftrace_graph_ent_entry *entry;
105
106 event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
107 sizeof(*entry), trace_ctx);
108 if (!event)
109 return 0;
110 entry = ring_buffer_event_data(event);
111 entry->graph_ent = *trace;
112 if (!call_filter_check_discard(call, entry, buffer, event))
113 trace_buffer_unlock_commit_nostack(buffer, event);
114
115 return 1;
116}
117
118static inline int ftrace_graph_ignore_irqs(void)
119{
120 if (!ftrace_graph_skip_irqs || trace_recursion_test(TRACE_IRQ_BIT))
121 return 0;
122
123 return in_hardirq();
124}
125
126int trace_graph_entry(struct ftrace_graph_ent *trace)
127{
128 struct trace_array *tr = graph_array;
129 struct trace_array_cpu *data;
130 unsigned long flags;
131 unsigned int trace_ctx;
132 long disabled;
133 int ret;
134 int cpu;
135
136 if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT))
137 return 0;
138
139 /*
140 * Do not trace a function if it's filtered by set_graph_notrace.
141 * Make the index of ret stack negative to indicate that it should
142 * ignore further functions. But it needs its own ret stack entry
143 * to recover the original index in order to continue tracing after
144 * returning from the function.
145 */
146 if (ftrace_graph_notrace_addr(trace->func)) {
147 trace_recursion_set(TRACE_GRAPH_NOTRACE_BIT);
148 /*
149 * Need to return 1 to have the return called
150 * that will clear the NOTRACE bit.
151 */
152 return 1;
153 }
154
155 if (!ftrace_trace_task(tr))
156 return 0;
157
158 if (ftrace_graph_ignore_func(trace))
159 return 0;
160
161 if (ftrace_graph_ignore_irqs())
162 return 0;
163
164 /*
165 * Stop here if tracing_threshold is set. We only write function return
166 * events to the ring buffer.
167 */
168 if (tracing_thresh)
169 return 1;
170
171 local_irq_save(flags);
172 cpu = raw_smp_processor_id();
173 data = per_cpu_ptr(tr->array_buffer.data, cpu);
174 disabled = atomic_inc_return(&data->disabled);
175 if (likely(disabled == 1)) {
176 trace_ctx = tracing_gen_ctx_flags(flags);
177 ret = __trace_graph_entry(tr, trace, trace_ctx);
178 } else {
179 ret = 0;
180 }
181
182 atomic_dec(&data->disabled);
183 local_irq_restore(flags);
184
185 return ret;
186}
187
188static void
189__trace_graph_function(struct trace_array *tr,
190 unsigned long ip, unsigned int trace_ctx)
191{
192 u64 time = trace_clock_local();
193 struct ftrace_graph_ent ent = {
194 .func = ip,
195 .depth = 0,
196 };
197 struct ftrace_graph_ret ret = {
198 .func = ip,
199 .depth = 0,
200 .calltime = time,
201 .rettime = time,
202 };
203
204 __trace_graph_entry(tr, &ent, trace_ctx);
205 __trace_graph_return(tr, &ret, trace_ctx);
206}
207
208void
209trace_graph_function(struct trace_array *tr,
210 unsigned long ip, unsigned long parent_ip,
211 unsigned int trace_ctx)
212{
213 __trace_graph_function(tr, ip, trace_ctx);
214}
215
216void __trace_graph_return(struct trace_array *tr,
217 struct ftrace_graph_ret *trace,
218 unsigned int trace_ctx)
219{
220 struct trace_event_call *call = &event_funcgraph_exit;
221 struct ring_buffer_event *event;
222 struct trace_buffer *buffer = tr->array_buffer.buffer;
223 struct ftrace_graph_ret_entry *entry;
224
225 event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
226 sizeof(*entry), trace_ctx);
227 if (!event)
228 return;
229 entry = ring_buffer_event_data(event);
230 entry->ret = *trace;
231 if (!call_filter_check_discard(call, entry, buffer, event))
232 trace_buffer_unlock_commit_nostack(buffer, event);
233}
234
235void trace_graph_return(struct ftrace_graph_ret *trace)
236{
237 struct trace_array *tr = graph_array;
238 struct trace_array_cpu *data;
239 unsigned long flags;
240 unsigned int trace_ctx;
241 long disabled;
242 int cpu;
243
244 ftrace_graph_addr_finish(trace);
245
246 if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
247 trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
248 return;
249 }
250
251 local_irq_save(flags);
252 cpu = raw_smp_processor_id();
253 data = per_cpu_ptr(tr->array_buffer.data, cpu);
254 disabled = atomic_inc_return(&data->disabled);
255 if (likely(disabled == 1)) {
256 trace_ctx = tracing_gen_ctx_flags(flags);
257 __trace_graph_return(tr, trace, trace_ctx);
258 }
259 atomic_dec(&data->disabled);
260 local_irq_restore(flags);
261}
262
263void set_graph_array(struct trace_array *tr)
264{
265 graph_array = tr;
266
267 /* Make graph_array visible before we start tracing */
268
269 smp_mb();
270}
271
272static void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
273{
274 ftrace_graph_addr_finish(trace);
275
276 if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
277 trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
278 return;
279 }
280
281 if (tracing_thresh &&
282 (trace->rettime - trace->calltime < tracing_thresh))
283 return;
284 else
285 trace_graph_return(trace);
286}
287
288static struct fgraph_ops funcgraph_thresh_ops = {
289 .entryfunc = &trace_graph_entry,
290 .retfunc = &trace_graph_thresh_return,
291};
292
293static struct fgraph_ops funcgraph_ops = {
294 .entryfunc = &trace_graph_entry,
295 .retfunc = &trace_graph_return,
296};
297
298static int graph_trace_init(struct trace_array *tr)
299{
300 int ret;
301
302 set_graph_array(tr);
303 if (tracing_thresh)
304 ret = register_ftrace_graph(&funcgraph_thresh_ops);
305 else
306 ret = register_ftrace_graph(&funcgraph_ops);
307 if (ret)
308 return ret;
309 tracing_start_cmdline_record();
310
311 return 0;
312}
313
314static void graph_trace_reset(struct trace_array *tr)
315{
316 tracing_stop_cmdline_record();
317 if (tracing_thresh)
318 unregister_ftrace_graph(&funcgraph_thresh_ops);
319 else
320 unregister_ftrace_graph(&funcgraph_ops);
321}
322
323static int graph_trace_update_thresh(struct trace_array *tr)
324{
325 graph_trace_reset(tr);
326 return graph_trace_init(tr);
327}
328
329static int max_bytes_for_cpu;
330
331static void print_graph_cpu(struct trace_seq *s, int cpu)
332{
333 /*
334 * Start with a space character - to make it stand out
335 * to the right a bit when trace output is pasted into
336 * email:
337 */
338 trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
339}
340
341#define TRACE_GRAPH_PROCINFO_LENGTH 14
342
343static void print_graph_proc(struct trace_seq *s, pid_t pid)
344{
345 char comm[TASK_COMM_LEN];
346 /* sign + log10(MAX_INT) + '\0' */
347 char pid_str[11];
348 int spaces = 0;
349 int len;
350 int i;
351
352 trace_find_cmdline(pid, comm);
353 comm[7] = '\0';
354 sprintf(pid_str, "%d", pid);
355
356 /* 1 stands for the "-" character */
357 len = strlen(comm) + strlen(pid_str) + 1;
358
359 if (len < TRACE_GRAPH_PROCINFO_LENGTH)
360 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
361
362 /* First spaces to align center */
363 for (i = 0; i < spaces / 2; i++)
364 trace_seq_putc(s, ' ');
365
366 trace_seq_printf(s, "%s-%s", comm, pid_str);
367
368 /* Last spaces to align center */
369 for (i = 0; i < spaces - (spaces / 2); i++)
370 trace_seq_putc(s, ' ');
371}
372
373
374static void print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
375{
376 trace_seq_putc(s, ' ');
377 trace_print_lat_fmt(s, entry);
378 trace_seq_puts(s, " | ");
379}
380
381/* If the pid changed since the last trace, output this event */
382static void
383verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
384{
385 pid_t prev_pid;
386 pid_t *last_pid;
387
388 if (!data)
389 return;
390
391 last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
392
393 if (*last_pid == pid)
394 return;
395
396 prev_pid = *last_pid;
397 *last_pid = pid;
398
399 if (prev_pid == -1)
400 return;
401/*
402 * Context-switch trace line:
403
404 ------------------------------------------
405 | 1) migration/0--1 => sshd-1755
406 ------------------------------------------
407
408 */
409 trace_seq_puts(s, " ------------------------------------------\n");
410 print_graph_cpu(s, cpu);
411 print_graph_proc(s, prev_pid);
412 trace_seq_puts(s, " => ");
413 print_graph_proc(s, pid);
414 trace_seq_puts(s, "\n ------------------------------------------\n\n");
415}
416
417static struct ftrace_graph_ret_entry *
418get_return_for_leaf(struct trace_iterator *iter,
419 struct ftrace_graph_ent_entry *curr)
420{
421 struct fgraph_data *data = iter->private;
422 struct ring_buffer_iter *ring_iter = NULL;
423 struct ring_buffer_event *event;
424 struct ftrace_graph_ret_entry *next;
425
426 /*
427 * If the previous output failed to write to the seq buffer,
428 * then we just reuse the data from before.
429 */
430 if (data && data->failed) {
431 curr = &data->ent;
432 next = &data->ret;
433 } else {
434
435 ring_iter = trace_buffer_iter(iter, iter->cpu);
436
437 /* First peek to compare current entry and the next one */
438 if (ring_iter)
439 event = ring_buffer_iter_peek(ring_iter, NULL);
440 else {
441 /*
442 * We need to consume the current entry to see
443 * the next one.
444 */
445 ring_buffer_consume(iter->array_buffer->buffer, iter->cpu,
446 NULL, NULL);
447 event = ring_buffer_peek(iter->array_buffer->buffer, iter->cpu,
448 NULL, NULL);
449 }
450
451 if (!event)
452 return NULL;
453
454 next = ring_buffer_event_data(event);
455
456 if (data) {
457 /*
458 * Save current and next entries for later reference
459 * if the output fails.
460 */
461 data->ent = *curr;
462 /*
463 * If the next event is not a return type, then
464 * we only care about what type it is. Otherwise we can
465 * safely copy the entire event.
466 */
467 if (next->ent.type == TRACE_GRAPH_RET)
468 data->ret = *next;
469 else
470 data->ret.ent.type = next->ent.type;
471 }
472 }
473
474 if (next->ent.type != TRACE_GRAPH_RET)
475 return NULL;
476
477 if (curr->ent.pid != next->ent.pid ||
478 curr->graph_ent.func != next->ret.func)
479 return NULL;
480
481 /* this is a leaf, now advance the iterator */
482 if (ring_iter)
483 ring_buffer_iter_advance(ring_iter);
484
485 return next;
486}
487
488static void print_graph_abs_time(u64 t, struct trace_seq *s)
489{
490 unsigned long usecs_rem;
491
492 usecs_rem = do_div(t, NSEC_PER_SEC);
493 usecs_rem /= 1000;
494
495 trace_seq_printf(s, "%5lu.%06lu | ",
496 (unsigned long)t, usecs_rem);
497}
498
499static void
500print_graph_rel_time(struct trace_iterator *iter, struct trace_seq *s)
501{
502 unsigned long long usecs;
503
504 usecs = iter->ts - iter->array_buffer->time_start;
505 do_div(usecs, NSEC_PER_USEC);
506
507 trace_seq_printf(s, "%9llu us | ", usecs);
508}
509
510static void
511print_graph_irq(struct trace_iterator *iter, unsigned long addr,
512 enum trace_type type, int cpu, pid_t pid, u32 flags)
513{
514 struct trace_array *tr = iter->tr;
515 struct trace_seq *s = &iter->seq;
516 struct trace_entry *ent = iter->ent;
517
518 if (addr < (unsigned long)__irqentry_text_start ||
519 addr >= (unsigned long)__irqentry_text_end)
520 return;
521
522 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
523 /* Absolute time */
524 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
525 print_graph_abs_time(iter->ts, s);
526
527 /* Relative time */
528 if (flags & TRACE_GRAPH_PRINT_REL_TIME)
529 print_graph_rel_time(iter, s);
530
531 /* Cpu */
532 if (flags & TRACE_GRAPH_PRINT_CPU)
533 print_graph_cpu(s, cpu);
534
535 /* Proc */
536 if (flags & TRACE_GRAPH_PRINT_PROC) {
537 print_graph_proc(s, pid);
538 trace_seq_puts(s, " | ");
539 }
540
541 /* Latency format */
542 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
543 print_graph_lat_fmt(s, ent);
544 }
545
546 /* No overhead */
547 print_graph_duration(tr, 0, s, flags | FLAGS_FILL_START);
548
549 if (type == TRACE_GRAPH_ENT)
550 trace_seq_puts(s, "==========>");
551 else
552 trace_seq_puts(s, "<==========");
553
554 print_graph_duration(tr, 0, s, flags | FLAGS_FILL_END);
555 trace_seq_putc(s, '\n');
556}
557
558void
559trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
560{
561 unsigned long nsecs_rem = do_div(duration, 1000);
562 /* log10(ULONG_MAX) + '\0' */
563 char usecs_str[21];
564 char nsecs_str[5];
565 int len;
566 int i;
567
568 sprintf(usecs_str, "%lu", (unsigned long) duration);
569
570 /* Print msecs */
571 trace_seq_printf(s, "%s", usecs_str);
572
573 len = strlen(usecs_str);
574
575 /* Print nsecs (we don't want to exceed 7 numbers) */
576 if (len < 7) {
577 size_t slen = min_t(size_t, sizeof(nsecs_str), 8UL - len);
578
579 snprintf(nsecs_str, slen, "%03lu", nsecs_rem);
580 trace_seq_printf(s, ".%s", nsecs_str);
581 len += strlen(nsecs_str) + 1;
582 }
583
584 trace_seq_puts(s, " us ");
585
586 /* Print remaining spaces to fit the row's width */
587 for (i = len; i < 8; i++)
588 trace_seq_putc(s, ' ');
589}
590
591static void
592print_graph_duration(struct trace_array *tr, unsigned long long duration,
593 struct trace_seq *s, u32 flags)
594{
595 if (!(flags & TRACE_GRAPH_PRINT_DURATION) ||
596 !(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
597 return;
598
599 /* No real adata, just filling the column with spaces */
600 switch (flags & TRACE_GRAPH_PRINT_FILL_MASK) {
601 case FLAGS_FILL_FULL:
602 trace_seq_puts(s, " | ");
603 return;
604 case FLAGS_FILL_START:
605 trace_seq_puts(s, " ");
606 return;
607 case FLAGS_FILL_END:
608 trace_seq_puts(s, " |");
609 return;
610 }
611
612 /* Signal a overhead of time execution to the output */
613 if (flags & TRACE_GRAPH_PRINT_OVERHEAD)
614 trace_seq_printf(s, "%c ", trace_find_mark(duration));
615 else
616 trace_seq_puts(s, " ");
617
618 trace_print_graph_duration(duration, s);
619 trace_seq_puts(s, "| ");
620}
621
622/* Case of a leaf function on its call entry */
623static enum print_line_t
624print_graph_entry_leaf(struct trace_iterator *iter,
625 struct ftrace_graph_ent_entry *entry,
626 struct ftrace_graph_ret_entry *ret_entry,
627 struct trace_seq *s, u32 flags)
628{
629 struct fgraph_data *data = iter->private;
630 struct trace_array *tr = iter->tr;
631 struct ftrace_graph_ret *graph_ret;
632 struct ftrace_graph_ent *call;
633 unsigned long long duration;
634 int cpu = iter->cpu;
635 int i;
636
637 graph_ret = &ret_entry->ret;
638 call = &entry->graph_ent;
639 duration = graph_ret->rettime - graph_ret->calltime;
640
641 if (data) {
642 struct fgraph_cpu_data *cpu_data;
643
644 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
645
646 /*
647 * Comments display at + 1 to depth. Since
648 * this is a leaf function, keep the comments
649 * equal to this depth.
650 */
651 cpu_data->depth = call->depth - 1;
652
653 /* No need to keep this function around for this depth */
654 if (call->depth < FTRACE_RETFUNC_DEPTH &&
655 !WARN_ON_ONCE(call->depth < 0))
656 cpu_data->enter_funcs[call->depth] = 0;
657 }
658
659 /* Overhead and duration */
660 print_graph_duration(tr, duration, s, flags);
661
662 /* Function */
663 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
664 trace_seq_putc(s, ' ');
665
666 trace_seq_printf(s, "%ps();\n", (void *)call->func);
667
668 print_graph_irq(iter, graph_ret->func, TRACE_GRAPH_RET,
669 cpu, iter->ent->pid, flags);
670
671 return trace_handle_return(s);
672}
673
674static enum print_line_t
675print_graph_entry_nested(struct trace_iterator *iter,
676 struct ftrace_graph_ent_entry *entry,
677 struct trace_seq *s, int cpu, u32 flags)
678{
679 struct ftrace_graph_ent *call = &entry->graph_ent;
680 struct fgraph_data *data = iter->private;
681 struct trace_array *tr = iter->tr;
682 int i;
683
684 if (data) {
685 struct fgraph_cpu_data *cpu_data;
686 int cpu = iter->cpu;
687
688 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
689 cpu_data->depth = call->depth;
690
691 /* Save this function pointer to see if the exit matches */
692 if (call->depth < FTRACE_RETFUNC_DEPTH &&
693 !WARN_ON_ONCE(call->depth < 0))
694 cpu_data->enter_funcs[call->depth] = call->func;
695 }
696
697 /* No time */
698 print_graph_duration(tr, 0, s, flags | FLAGS_FILL_FULL);
699
700 /* Function */
701 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
702 trace_seq_putc(s, ' ');
703
704 trace_seq_printf(s, "%ps() {\n", (void *)call->func);
705
706 if (trace_seq_has_overflowed(s))
707 return TRACE_TYPE_PARTIAL_LINE;
708
709 /*
710 * we already consumed the current entry to check the next one
711 * and see if this is a leaf.
712 */
713 return TRACE_TYPE_NO_CONSUME;
714}
715
716static void
717print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
718 int type, unsigned long addr, u32 flags)
719{
720 struct fgraph_data *data = iter->private;
721 struct trace_entry *ent = iter->ent;
722 struct trace_array *tr = iter->tr;
723 int cpu = iter->cpu;
724
725 /* Pid */
726 verif_pid(s, ent->pid, cpu, data);
727
728 if (type)
729 /* Interrupt */
730 print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
731
732 if (!(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
733 return;
734
735 /* Absolute time */
736 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
737 print_graph_abs_time(iter->ts, s);
738
739 /* Relative time */
740 if (flags & TRACE_GRAPH_PRINT_REL_TIME)
741 print_graph_rel_time(iter, s);
742
743 /* Cpu */
744 if (flags & TRACE_GRAPH_PRINT_CPU)
745 print_graph_cpu(s, cpu);
746
747 /* Proc */
748 if (flags & TRACE_GRAPH_PRINT_PROC) {
749 print_graph_proc(s, ent->pid);
750 trace_seq_puts(s, " | ");
751 }
752
753 /* Latency format */
754 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
755 print_graph_lat_fmt(s, ent);
756
757 return;
758}
759
760/*
761 * Entry check for irq code
762 *
763 * returns 1 if
764 * - we are inside irq code
765 * - we just entered irq code
766 *
767 * returns 0 if
768 * - funcgraph-interrupts option is set
769 * - we are not inside irq code
770 */
771static int
772check_irq_entry(struct trace_iterator *iter, u32 flags,
773 unsigned long addr, int depth)
774{
775 int cpu = iter->cpu;
776 int *depth_irq;
777 struct fgraph_data *data = iter->private;
778
779 /*
780 * If we are either displaying irqs, or we got called as
781 * a graph event and private data does not exist,
782 * then we bypass the irq check.
783 */
784 if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
785 (!data))
786 return 0;
787
788 depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
789
790 /*
791 * We are inside the irq code
792 */
793 if (*depth_irq >= 0)
794 return 1;
795
796 if ((addr < (unsigned long)__irqentry_text_start) ||
797 (addr >= (unsigned long)__irqentry_text_end))
798 return 0;
799
800 /*
801 * We are entering irq code.
802 */
803 *depth_irq = depth;
804 return 1;
805}
806
807/*
808 * Return check for irq code
809 *
810 * returns 1 if
811 * - we are inside irq code
812 * - we just left irq code
813 *
814 * returns 0 if
815 * - funcgraph-interrupts option is set
816 * - we are not inside irq code
817 */
818static int
819check_irq_return(struct trace_iterator *iter, u32 flags, int depth)
820{
821 int cpu = iter->cpu;
822 int *depth_irq;
823 struct fgraph_data *data = iter->private;
824
825 /*
826 * If we are either displaying irqs, or we got called as
827 * a graph event and private data does not exist,
828 * then we bypass the irq check.
829 */
830 if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
831 (!data))
832 return 0;
833
834 depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
835
836 /*
837 * We are not inside the irq code.
838 */
839 if (*depth_irq == -1)
840 return 0;
841
842 /*
843 * We are inside the irq code, and this is returning entry.
844 * Let's not trace it and clear the entry depth, since
845 * we are out of irq code.
846 *
847 * This condition ensures that we 'leave the irq code' once
848 * we are out of the entry depth. Thus protecting us from
849 * the RETURN entry loss.
850 */
851 if (*depth_irq >= depth) {
852 *depth_irq = -1;
853 return 1;
854 }
855
856 /*
857 * We are inside the irq code, and this is not the entry.
858 */
859 return 1;
860}
861
862static enum print_line_t
863print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
864 struct trace_iterator *iter, u32 flags)
865{
866 struct fgraph_data *data = iter->private;
867 struct ftrace_graph_ent *call = &field->graph_ent;
868 struct ftrace_graph_ret_entry *leaf_ret;
869 static enum print_line_t ret;
870 int cpu = iter->cpu;
871
872 if (check_irq_entry(iter, flags, call->func, call->depth))
873 return TRACE_TYPE_HANDLED;
874
875 print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags);
876
877 leaf_ret = get_return_for_leaf(iter, field);
878 if (leaf_ret)
879 ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags);
880 else
881 ret = print_graph_entry_nested(iter, field, s, cpu, flags);
882
883 if (data) {
884 /*
885 * If we failed to write our output, then we need to make
886 * note of it. Because we already consumed our entry.
887 */
888 if (s->full) {
889 data->failed = 1;
890 data->cpu = cpu;
891 } else
892 data->failed = 0;
893 }
894
895 return ret;
896}
897
898static enum print_line_t
899print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
900 struct trace_entry *ent, struct trace_iterator *iter,
901 u32 flags)
902{
903 unsigned long long duration = trace->rettime - trace->calltime;
904 struct fgraph_data *data = iter->private;
905 struct trace_array *tr = iter->tr;
906 pid_t pid = ent->pid;
907 int cpu = iter->cpu;
908 int func_match = 1;
909 int i;
910
911 if (check_irq_return(iter, flags, trace->depth))
912 return TRACE_TYPE_HANDLED;
913
914 if (data) {
915 struct fgraph_cpu_data *cpu_data;
916 int cpu = iter->cpu;
917
918 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
919
920 /*
921 * Comments display at + 1 to depth. This is the
922 * return from a function, we now want the comments
923 * to display at the same level of the bracket.
924 */
925 cpu_data->depth = trace->depth - 1;
926
927 if (trace->depth < FTRACE_RETFUNC_DEPTH &&
928 !WARN_ON_ONCE(trace->depth < 0)) {
929 if (cpu_data->enter_funcs[trace->depth] != trace->func)
930 func_match = 0;
931 cpu_data->enter_funcs[trace->depth] = 0;
932 }
933 }
934
935 print_graph_prologue(iter, s, 0, 0, flags);
936
937 /* Overhead and duration */
938 print_graph_duration(tr, duration, s, flags);
939
940 /* Closing brace */
941 for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++)
942 trace_seq_putc(s, ' ');
943
944 /*
945 * If the return function does not have a matching entry,
946 * then the entry was lost. Instead of just printing
947 * the '}' and letting the user guess what function this
948 * belongs to, write out the function name. Always do
949 * that if the funcgraph-tail option is enabled.
950 */
951 if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL))
952 trace_seq_puts(s, "}\n");
953 else
954 trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
955
956 /* Overrun */
957 if (flags & TRACE_GRAPH_PRINT_OVERRUN)
958 trace_seq_printf(s, " (Overruns: %u)\n",
959 trace->overrun);
960
961 print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
962 cpu, pid, flags);
963
964 return trace_handle_return(s);
965}
966
967static enum print_line_t
968print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
969 struct trace_iterator *iter, u32 flags)
970{
971 struct trace_array *tr = iter->tr;
972 unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
973 struct fgraph_data *data = iter->private;
974 struct trace_event *event;
975 int depth = 0;
976 int ret;
977 int i;
978
979 if (data)
980 depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
981
982 print_graph_prologue(iter, s, 0, 0, flags);
983
984 /* No time */
985 print_graph_duration(tr, 0, s, flags | FLAGS_FILL_FULL);
986
987 /* Indentation */
988 if (depth > 0)
989 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++)
990 trace_seq_putc(s, ' ');
991
992 /* The comment */
993 trace_seq_puts(s, "/* ");
994
995 switch (iter->ent->type) {
996 case TRACE_BPUTS:
997 ret = trace_print_bputs_msg_only(iter);
998 if (ret != TRACE_TYPE_HANDLED)
999 return ret;
1000 break;
1001 case TRACE_BPRINT:
1002 ret = trace_print_bprintk_msg_only(iter);
1003 if (ret != TRACE_TYPE_HANDLED)
1004 return ret;
1005 break;
1006 case TRACE_PRINT:
1007 ret = trace_print_printk_msg_only(iter);
1008 if (ret != TRACE_TYPE_HANDLED)
1009 return ret;
1010 break;
1011 default:
1012 event = ftrace_find_event(ent->type);
1013 if (!event)
1014 return TRACE_TYPE_UNHANDLED;
1015
1016 ret = event->funcs->trace(iter, sym_flags, event);
1017 if (ret != TRACE_TYPE_HANDLED)
1018 return ret;
1019 }
1020
1021 if (trace_seq_has_overflowed(s))
1022 goto out;
1023
1024 /* Strip ending newline */
1025 if (s->buffer[s->seq.len - 1] == '\n') {
1026 s->buffer[s->seq.len - 1] = '\0';
1027 s->seq.len--;
1028 }
1029
1030 trace_seq_puts(s, " */\n");
1031 out:
1032 return trace_handle_return(s);
1033}
1034
1035
1036enum print_line_t
1037print_graph_function_flags(struct trace_iterator *iter, u32 flags)
1038{
1039 struct ftrace_graph_ent_entry *field;
1040 struct fgraph_data *data = iter->private;
1041 struct trace_entry *entry = iter->ent;
1042 struct trace_seq *s = &iter->seq;
1043 int cpu = iter->cpu;
1044 int ret;
1045
1046 if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
1047 per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
1048 return TRACE_TYPE_HANDLED;
1049 }
1050
1051 /*
1052 * If the last output failed, there's a possibility we need
1053 * to print out the missing entry which would never go out.
1054 */
1055 if (data && data->failed) {
1056 field = &data->ent;
1057 iter->cpu = data->cpu;
1058 ret = print_graph_entry(field, s, iter, flags);
1059 if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
1060 per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
1061 ret = TRACE_TYPE_NO_CONSUME;
1062 }
1063 iter->cpu = cpu;
1064 return ret;
1065 }
1066
1067 switch (entry->type) {
1068 case TRACE_GRAPH_ENT: {
1069 /*
1070 * print_graph_entry() may consume the current event,
1071 * thus @field may become invalid, so we need to save it.
1072 * sizeof(struct ftrace_graph_ent_entry) is very small,
1073 * it can be safely saved at the stack.
1074 */
1075 struct ftrace_graph_ent_entry saved;
1076 trace_assign_type(field, entry);
1077 saved = *field;
1078 return print_graph_entry(&saved, s, iter, flags);
1079 }
1080 case TRACE_GRAPH_RET: {
1081 struct ftrace_graph_ret_entry *field;
1082 trace_assign_type(field, entry);
1083 return print_graph_return(&field->ret, s, entry, iter, flags);
1084 }
1085 case TRACE_STACK:
1086 case TRACE_FN:
1087 /* dont trace stack and functions as comments */
1088 return TRACE_TYPE_UNHANDLED;
1089
1090 default:
1091 return print_graph_comment(s, entry, iter, flags);
1092 }
1093
1094 return TRACE_TYPE_HANDLED;
1095}
1096
1097static enum print_line_t
1098print_graph_function(struct trace_iterator *iter)
1099{
1100 return print_graph_function_flags(iter, tracer_flags.val);
1101}
1102
1103static enum print_line_t
1104print_graph_function_event(struct trace_iterator *iter, int flags,
1105 struct trace_event *event)
1106{
1107 return print_graph_function(iter);
1108}
1109
1110static void print_lat_header(struct seq_file *s, u32 flags)
1111{
1112 static const char spaces[] = " " /* 16 spaces */
1113 " " /* 4 spaces */
1114 " "; /* 17 spaces */
1115 int size = 0;
1116
1117 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1118 size += 16;
1119 if (flags & TRACE_GRAPH_PRINT_REL_TIME)
1120 size += 16;
1121 if (flags & TRACE_GRAPH_PRINT_CPU)
1122 size += 4;
1123 if (flags & TRACE_GRAPH_PRINT_PROC)
1124 size += 17;
1125
1126 seq_printf(s, "#%.*s _-----=> irqs-off \n", size, spaces);
1127 seq_printf(s, "#%.*s / _----=> need-resched \n", size, spaces);
1128 seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
1129 seq_printf(s, "#%.*s|| / _--=> preempt-depth \n", size, spaces);
1130 seq_printf(s, "#%.*s||| / \n", size, spaces);
1131}
1132
1133static void __print_graph_headers_flags(struct trace_array *tr,
1134 struct seq_file *s, u32 flags)
1135{
1136 int lat = tr->trace_flags & TRACE_ITER_LATENCY_FMT;
1137
1138 if (lat)
1139 print_lat_header(s, flags);
1140
1141 /* 1st line */
1142 seq_putc(s, '#');
1143 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1144 seq_puts(s, " TIME ");
1145 if (flags & TRACE_GRAPH_PRINT_REL_TIME)
1146 seq_puts(s, " REL TIME ");
1147 if (flags & TRACE_GRAPH_PRINT_CPU)
1148 seq_puts(s, " CPU");
1149 if (flags & TRACE_GRAPH_PRINT_PROC)
1150 seq_puts(s, " TASK/PID ");
1151 if (lat)
1152 seq_puts(s, "|||| ");
1153 if (flags & TRACE_GRAPH_PRINT_DURATION)
1154 seq_puts(s, " DURATION ");
1155 seq_puts(s, " FUNCTION CALLS\n");
1156
1157 /* 2nd line */
1158 seq_putc(s, '#');
1159 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1160 seq_puts(s, " | ");
1161 if (flags & TRACE_GRAPH_PRINT_REL_TIME)
1162 seq_puts(s, " | ");
1163 if (flags & TRACE_GRAPH_PRINT_CPU)
1164 seq_puts(s, " | ");
1165 if (flags & TRACE_GRAPH_PRINT_PROC)
1166 seq_puts(s, " | | ");
1167 if (lat)
1168 seq_puts(s, "|||| ");
1169 if (flags & TRACE_GRAPH_PRINT_DURATION)
1170 seq_puts(s, " | | ");
1171 seq_puts(s, " | | | |\n");
1172}
1173
1174static void print_graph_headers(struct seq_file *s)
1175{
1176 print_graph_headers_flags(s, tracer_flags.val);
1177}
1178
1179void print_graph_headers_flags(struct seq_file *s, u32 flags)
1180{
1181 struct trace_iterator *iter = s->private;
1182 struct trace_array *tr = iter->tr;
1183
1184 if (!(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
1185 return;
1186
1187 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT) {
1188 /* print nothing if the buffers are empty */
1189 if (trace_empty(iter))
1190 return;
1191
1192 print_trace_header(s, iter);
1193 }
1194
1195 __print_graph_headers_flags(tr, s, flags);
1196}
1197
1198void graph_trace_open(struct trace_iterator *iter)
1199{
1200 /* pid and depth on the last trace processed */
1201 struct fgraph_data *data;
1202 gfp_t gfpflags;
1203 int cpu;
1204
1205 iter->private = NULL;
1206
1207 /* We can be called in atomic context via ftrace_dump() */
1208 gfpflags = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL;
1209
1210 data = kzalloc(sizeof(*data), gfpflags);
1211 if (!data)
1212 goto out_err;
1213
1214 data->cpu_data = alloc_percpu_gfp(struct fgraph_cpu_data, gfpflags);
1215 if (!data->cpu_data)
1216 goto out_err_free;
1217
1218 for_each_possible_cpu(cpu) {
1219 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
1220 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
1221 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
1222 int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1223
1224 *pid = -1;
1225 *depth = 0;
1226 *ignore = 0;
1227 *depth_irq = -1;
1228 }
1229
1230 iter->private = data;
1231
1232 return;
1233
1234 out_err_free:
1235 kfree(data);
1236 out_err:
1237 pr_warn("function graph tracer: not enough memory\n");
1238}
1239
1240void graph_trace_close(struct trace_iterator *iter)
1241{
1242 struct fgraph_data *data = iter->private;
1243
1244 if (data) {
1245 free_percpu(data->cpu_data);
1246 kfree(data);
1247 }
1248}
1249
1250static int
1251func_graph_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1252{
1253 if (bit == TRACE_GRAPH_PRINT_IRQS)
1254 ftrace_graph_skip_irqs = !set;
1255
1256 if (bit == TRACE_GRAPH_SLEEP_TIME)
1257 ftrace_graph_sleep_time_control(set);
1258
1259 if (bit == TRACE_GRAPH_GRAPH_TIME)
1260 ftrace_graph_graph_time_control(set);
1261
1262 return 0;
1263}
1264
1265static struct trace_event_functions graph_functions = {
1266 .trace = print_graph_function_event,
1267};
1268
1269static struct trace_event graph_trace_entry_event = {
1270 .type = TRACE_GRAPH_ENT,
1271 .funcs = &graph_functions,
1272};
1273
1274static struct trace_event graph_trace_ret_event = {
1275 .type = TRACE_GRAPH_RET,
1276 .funcs = &graph_functions
1277};
1278
1279static struct tracer graph_trace __tracer_data = {
1280 .name = "function_graph",
1281 .update_thresh = graph_trace_update_thresh,
1282 .open = graph_trace_open,
1283 .pipe_open = graph_trace_open,
1284 .close = graph_trace_close,
1285 .pipe_close = graph_trace_close,
1286 .init = graph_trace_init,
1287 .reset = graph_trace_reset,
1288 .print_line = print_graph_function,
1289 .print_header = print_graph_headers,
1290 .flags = &tracer_flags,
1291 .set_flag = func_graph_set_flag,
1292#ifdef CONFIG_FTRACE_SELFTEST
1293 .selftest = trace_selftest_startup_function_graph,
1294#endif
1295};
1296
1297
1298static ssize_t
1299graph_depth_write(struct file *filp, const char __user *ubuf, size_t cnt,
1300 loff_t *ppos)
1301{
1302 unsigned long val;
1303 int ret;
1304
1305 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1306 if (ret)
1307 return ret;
1308
1309 fgraph_max_depth = val;
1310
1311 *ppos += cnt;
1312
1313 return cnt;
1314}
1315
1316static ssize_t
1317graph_depth_read(struct file *filp, char __user *ubuf, size_t cnt,
1318 loff_t *ppos)
1319{
1320 char buf[15]; /* More than enough to hold UINT_MAX + "\n"*/
1321 int n;
1322
1323 n = sprintf(buf, "%d\n", fgraph_max_depth);
1324
1325 return simple_read_from_buffer(ubuf, cnt, ppos, buf, n);
1326}
1327
1328static const struct file_operations graph_depth_fops = {
1329 .open = tracing_open_generic,
1330 .write = graph_depth_write,
1331 .read = graph_depth_read,
1332 .llseek = generic_file_llseek,
1333};
1334
1335static __init int init_graph_tracefs(void)
1336{
1337 int ret;
1338
1339 ret = tracing_init_dentry();
1340 if (ret)
1341 return 0;
1342
1343 trace_create_file("max_graph_depth", TRACE_MODE_WRITE, NULL,
1344 NULL, &graph_depth_fops);
1345
1346 return 0;
1347}
1348fs_initcall(init_graph_tracefs);
1349
1350static __init int init_graph_trace(void)
1351{
1352 max_bytes_for_cpu = snprintf(NULL, 0, "%u", nr_cpu_ids - 1);
1353
1354 if (!register_trace_event(&graph_trace_entry_event)) {
1355 pr_warn("Warning: could not register graph trace events\n");
1356 return 1;
1357 }
1358
1359 if (!register_trace_event(&graph_trace_ret_event)) {
1360 pr_warn("Warning: could not register graph trace events\n");
1361 return 1;
1362 }
1363
1364 return register_tracer(&graph_trace);
1365}
1366
1367core_initcall(init_graph_trace);
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/uaccess.h>
10#include <linux/ftrace.h>
11#include <linux/interrupt.h>
12#include <linux/slab.h>
13#include <linux/fs.h>
14
15#include "trace.h"
16#include "trace_output.h"
17
18static 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 */
27bool 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 */
40void ftrace_graph_stop(void)
41{
42 kill_ftrace_graph = true;
43}
44
45/* When set, irq functions will be ignored */
46static int ftrace_graph_skip_irqs;
47
48struct fgraph_cpu_data {
49 pid_t last_pid;
50 int depth;
51 int depth_irq;
52 int ignore;
53 unsigned long enter_funcs[FTRACE_RETFUNC_DEPTH];
54};
55
56struct fgraph_data {
57 struct fgraph_cpu_data __percpu *cpu_data;
58
59 /* Place to preserve last processed entry. */
60 struct ftrace_graph_ent_entry ent;
61 struct ftrace_graph_ret_entry ret;
62 int failed;
63 int cpu;
64};
65
66#define TRACE_GRAPH_INDENT 2
67
68unsigned int fgraph_max_depth;
69
70static struct tracer_opt trace_opts[] = {
71 /* Display overruns? (for self-debug purpose) */
72 { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
73 /* Display CPU ? */
74 { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
75 /* Display Overhead ? */
76 { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
77 /* Display proc name/pid */
78 { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
79 /* Display duration of execution */
80 { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
81 /* Display absolute time of an entry */
82 { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
83 /* Display interrupts */
84 { TRACER_OPT(funcgraph-irqs, TRACE_GRAPH_PRINT_IRQS) },
85 /* Display function name after trailing } */
86 { TRACER_OPT(funcgraph-tail, TRACE_GRAPH_PRINT_TAIL) },
87 /* Include sleep time (scheduled out) between entry and return */
88 { TRACER_OPT(sleep-time, TRACE_GRAPH_SLEEP_TIME) },
89 /* Include time within nested functions */
90 { TRACER_OPT(graph-time, TRACE_GRAPH_GRAPH_TIME) },
91 { } /* Empty entry */
92};
93
94static struct tracer_flags tracer_flags = {
95 /* Don't display overruns, proc, or tail by default */
96 .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
97 TRACE_GRAPH_PRINT_DURATION | TRACE_GRAPH_PRINT_IRQS |
98 TRACE_GRAPH_SLEEP_TIME | TRACE_GRAPH_GRAPH_TIME,
99 .opts = trace_opts
100};
101
102static 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 */
109enum {
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
115static void
116print_graph_duration(struct trace_array *tr, unsigned long long duration,
117 struct trace_seq *s, u32 flags);
118
119/* Add a function return address to the trace stack on thread info.*/
120int
121ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
122 unsigned long frame_pointer, unsigned long *retp)
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(¤t->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 tracefs 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#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
174 current->ret_stack[index].fp = frame_pointer;
175#endif
176#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
177 current->ret_stack[index].retp = retp;
178#endif
179 *depth = current->curr_ret_stack;
180
181 return 0;
182}
183
184/* Retrieve a function return address to the trace stack on thread info.*/
185static void
186ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
187 unsigned long frame_pointer)
188{
189 int index;
190
191 index = current->curr_ret_stack;
192
193 /*
194 * A negative index here means that it's just returned from a
195 * notrace'd function. Recover index to get an original
196 * return address. See ftrace_push_return_trace().
197 *
198 * TODO: Need to check whether the stack gets corrupted.
199 */
200 if (index < 0)
201 index += FTRACE_NOTRACE_DEPTH;
202
203 if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) {
204 ftrace_graph_stop();
205 WARN_ON(1);
206 /* Might as well panic, otherwise we have no where to go */
207 *ret = (unsigned long)panic;
208 return;
209 }
210
211#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
212 /*
213 * The arch may choose to record the frame pointer used
214 * and check it here to make sure that it is what we expect it
215 * to be. If gcc does not set the place holder of the return
216 * address in the frame pointer, and does a copy instead, then
217 * the function graph trace will fail. This test detects this
218 * case.
219 *
220 * Currently, x86_32 with optimize for size (-Os) makes the latest
221 * gcc do the above.
222 *
223 * Note, -mfentry does not use frame pointers, and this test
224 * is not needed if CC_USING_FENTRY is set.
225 */
226 if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
227 ftrace_graph_stop();
228 WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
229 " from func %ps return to %lx\n",
230 current->ret_stack[index].fp,
231 frame_pointer,
232 (void *)current->ret_stack[index].func,
233 current->ret_stack[index].ret);
234 *ret = (unsigned long)panic;
235 return;
236 }
237#endif
238
239 *ret = current->ret_stack[index].ret;
240 trace->func = current->ret_stack[index].func;
241 trace->calltime = current->ret_stack[index].calltime;
242 trace->overrun = atomic_read(¤t->trace_overrun);
243 trace->depth = index;
244}
245
246/*
247 * Send the trace to the ring-buffer.
248 * @return the original return address.
249 */
250unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
251{
252 struct ftrace_graph_ret trace;
253 unsigned long ret;
254
255 ftrace_pop_return_trace(&trace, &ret, frame_pointer);
256 trace.rettime = trace_clock_local();
257 barrier();
258 current->curr_ret_stack--;
259 /*
260 * The curr_ret_stack can be less than -1 only if it was
261 * filtered out and it's about to return from the function.
262 * Recover the index and continue to trace normal functions.
263 */
264 if (current->curr_ret_stack < -1) {
265 current->curr_ret_stack += FTRACE_NOTRACE_DEPTH;
266 return ret;
267 }
268
269 /*
270 * The trace should run after decrementing the ret counter
271 * in case an interrupt were to come in. We don't want to
272 * lose the interrupt if max_depth is set.
273 */
274 ftrace_graph_return(&trace);
275
276 if (unlikely(!ret)) {
277 ftrace_graph_stop();
278 WARN_ON(1);
279 /* Might as well panic. What else to do? */
280 ret = (unsigned long)panic;
281 }
282
283 return ret;
284}
285
286/**
287 * ftrace_graph_ret_addr - convert a potentially modified stack return address
288 * to its original value
289 *
290 * This function can be called by stack unwinding code to convert a found stack
291 * return address ('ret') to its original value, in case the function graph
292 * tracer has modified it to be 'return_to_handler'. If the address hasn't
293 * been modified, the unchanged value of 'ret' is returned.
294 *
295 * 'idx' is a state variable which should be initialized by the caller to zero
296 * before the first call.
297 *
298 * 'retp' is a pointer to the return address on the stack. It's ignored if
299 * the arch doesn't have HAVE_FUNCTION_GRAPH_RET_ADDR_PTR defined.
300 */
301#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
302unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
303 unsigned long ret, unsigned long *retp)
304{
305 int index = task->curr_ret_stack;
306 int i;
307
308 if (ret != (unsigned long)return_to_handler)
309 return ret;
310
311 if (index < -1)
312 index += FTRACE_NOTRACE_DEPTH;
313
314 if (index < 0)
315 return ret;
316
317 for (i = 0; i <= index; i++)
318 if (task->ret_stack[i].retp == retp)
319 return task->ret_stack[i].ret;
320
321 return ret;
322}
323#else /* !HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */
324unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
325 unsigned long ret, unsigned long *retp)
326{
327 int task_idx;
328
329 if (ret != (unsigned long)return_to_handler)
330 return ret;
331
332 task_idx = task->curr_ret_stack;
333
334 if (!task->ret_stack || task_idx < *idx)
335 return ret;
336
337 task_idx -= *idx;
338 (*idx)++;
339
340 return task->ret_stack[task_idx].ret;
341}
342#endif /* HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */
343
344int __trace_graph_entry(struct trace_array *tr,
345 struct ftrace_graph_ent *trace,
346 unsigned long flags,
347 int pc)
348{
349 struct trace_event_call *call = &event_funcgraph_entry;
350 struct ring_buffer_event *event;
351 struct ring_buffer *buffer = tr->trace_buffer.buffer;
352 struct ftrace_graph_ent_entry *entry;
353
354 event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
355 sizeof(*entry), flags, pc);
356 if (!event)
357 return 0;
358 entry = ring_buffer_event_data(event);
359 entry->graph_ent = *trace;
360 if (!call_filter_check_discard(call, entry, buffer, event))
361 trace_buffer_unlock_commit_nostack(buffer, event);
362
363 return 1;
364}
365
366static inline int ftrace_graph_ignore_irqs(void)
367{
368 if (!ftrace_graph_skip_irqs || trace_recursion_test(TRACE_IRQ_BIT))
369 return 0;
370
371 return in_irq();
372}
373
374int trace_graph_entry(struct ftrace_graph_ent *trace)
375{
376 struct trace_array *tr = graph_array;
377 struct trace_array_cpu *data;
378 unsigned long flags;
379 long disabled;
380 int ret;
381 int cpu;
382 int pc;
383
384 if (!ftrace_trace_task(tr))
385 return 0;
386
387 if (ftrace_graph_ignore_func(trace))
388 return 0;
389
390 if (ftrace_graph_ignore_irqs())
391 return 0;
392
393 /*
394 * Do not trace a function if it's filtered by set_graph_notrace.
395 * Make the index of ret stack negative to indicate that it should
396 * ignore further functions. But it needs its own ret stack entry
397 * to recover the original index in order to continue tracing after
398 * returning from the function.
399 */
400 if (ftrace_graph_notrace_addr(trace->func))
401 return 1;
402
403 /*
404 * Stop here if tracing_threshold is set. We only write function return
405 * events to the ring buffer.
406 */
407 if (tracing_thresh)
408 return 1;
409
410 local_irq_save(flags);
411 cpu = raw_smp_processor_id();
412 data = per_cpu_ptr(tr->trace_buffer.data, cpu);
413 disabled = atomic_inc_return(&data->disabled);
414 if (likely(disabled == 1)) {
415 pc = preempt_count();
416 ret = __trace_graph_entry(tr, trace, flags, pc);
417 } else {
418 ret = 0;
419 }
420
421 atomic_dec(&data->disabled);
422 local_irq_restore(flags);
423
424 return ret;
425}
426
427static void
428__trace_graph_function(struct trace_array *tr,
429 unsigned long ip, unsigned long flags, int pc)
430{
431 u64 time = trace_clock_local();
432 struct ftrace_graph_ent ent = {
433 .func = ip,
434 .depth = 0,
435 };
436 struct ftrace_graph_ret ret = {
437 .func = ip,
438 .depth = 0,
439 .calltime = time,
440 .rettime = time,
441 };
442
443 __trace_graph_entry(tr, &ent, flags, pc);
444 __trace_graph_return(tr, &ret, flags, pc);
445}
446
447void
448trace_graph_function(struct trace_array *tr,
449 unsigned long ip, unsigned long parent_ip,
450 unsigned long flags, int pc)
451{
452 __trace_graph_function(tr, ip, flags, pc);
453}
454
455void __trace_graph_return(struct trace_array *tr,
456 struct ftrace_graph_ret *trace,
457 unsigned long flags,
458 int pc)
459{
460 struct trace_event_call *call = &event_funcgraph_exit;
461 struct ring_buffer_event *event;
462 struct ring_buffer *buffer = tr->trace_buffer.buffer;
463 struct ftrace_graph_ret_entry *entry;
464
465 event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
466 sizeof(*entry), flags, pc);
467 if (!event)
468 return;
469 entry = ring_buffer_event_data(event);
470 entry->ret = *trace;
471 if (!call_filter_check_discard(call, entry, buffer, event))
472 trace_buffer_unlock_commit_nostack(buffer, event);
473}
474
475void trace_graph_return(struct ftrace_graph_ret *trace)
476{
477 struct trace_array *tr = graph_array;
478 struct trace_array_cpu *data;
479 unsigned long flags;
480 long disabled;
481 int cpu;
482 int pc;
483
484 local_irq_save(flags);
485 cpu = raw_smp_processor_id();
486 data = per_cpu_ptr(tr->trace_buffer.data, cpu);
487 disabled = atomic_inc_return(&data->disabled);
488 if (likely(disabled == 1)) {
489 pc = preempt_count();
490 __trace_graph_return(tr, trace, flags, pc);
491 }
492 atomic_dec(&data->disabled);
493 local_irq_restore(flags);
494}
495
496void set_graph_array(struct trace_array *tr)
497{
498 graph_array = tr;
499
500 /* Make graph_array visible before we start tracing */
501
502 smp_mb();
503}
504
505static void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
506{
507 if (tracing_thresh &&
508 (trace->rettime - trace->calltime < tracing_thresh))
509 return;
510 else
511 trace_graph_return(trace);
512}
513
514static int graph_trace_init(struct trace_array *tr)
515{
516 int ret;
517
518 set_graph_array(tr);
519 if (tracing_thresh)
520 ret = register_ftrace_graph(&trace_graph_thresh_return,
521 &trace_graph_entry);
522 else
523 ret = register_ftrace_graph(&trace_graph_return,
524 &trace_graph_entry);
525 if (ret)
526 return ret;
527 tracing_start_cmdline_record();
528
529 return 0;
530}
531
532static void graph_trace_reset(struct trace_array *tr)
533{
534 tracing_stop_cmdline_record();
535 unregister_ftrace_graph();
536}
537
538static int graph_trace_update_thresh(struct trace_array *tr)
539{
540 graph_trace_reset(tr);
541 return graph_trace_init(tr);
542}
543
544static int max_bytes_for_cpu;
545
546static void print_graph_cpu(struct trace_seq *s, int cpu)
547{
548 /*
549 * Start with a space character - to make it stand out
550 * to the right a bit when trace output is pasted into
551 * email:
552 */
553 trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
554}
555
556#define TRACE_GRAPH_PROCINFO_LENGTH 14
557
558static void print_graph_proc(struct trace_seq *s, pid_t pid)
559{
560 char comm[TASK_COMM_LEN];
561 /* sign + log10(MAX_INT) + '\0' */
562 char pid_str[11];
563 int spaces = 0;
564 int len;
565 int i;
566
567 trace_find_cmdline(pid, comm);
568 comm[7] = '\0';
569 sprintf(pid_str, "%d", pid);
570
571 /* 1 stands for the "-" character */
572 len = strlen(comm) + strlen(pid_str) + 1;
573
574 if (len < TRACE_GRAPH_PROCINFO_LENGTH)
575 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
576
577 /* First spaces to align center */
578 for (i = 0; i < spaces / 2; i++)
579 trace_seq_putc(s, ' ');
580
581 trace_seq_printf(s, "%s-%s", comm, pid_str);
582
583 /* Last spaces to align center */
584 for (i = 0; i < spaces - (spaces / 2); i++)
585 trace_seq_putc(s, ' ');
586}
587
588
589static void print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
590{
591 trace_seq_putc(s, ' ');
592 trace_print_lat_fmt(s, entry);
593}
594
595/* If the pid changed since the last trace, output this event */
596static void
597verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
598{
599 pid_t prev_pid;
600 pid_t *last_pid;
601
602 if (!data)
603 return;
604
605 last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
606
607 if (*last_pid == pid)
608 return;
609
610 prev_pid = *last_pid;
611 *last_pid = pid;
612
613 if (prev_pid == -1)
614 return;
615/*
616 * Context-switch trace line:
617
618 ------------------------------------------
619 | 1) migration/0--1 => sshd-1755
620 ------------------------------------------
621
622 */
623 trace_seq_puts(s, " ------------------------------------------\n");
624 print_graph_cpu(s, cpu);
625 print_graph_proc(s, prev_pid);
626 trace_seq_puts(s, " => ");
627 print_graph_proc(s, pid);
628 trace_seq_puts(s, "\n ------------------------------------------\n\n");
629}
630
631static struct ftrace_graph_ret_entry *
632get_return_for_leaf(struct trace_iterator *iter,
633 struct ftrace_graph_ent_entry *curr)
634{
635 struct fgraph_data *data = iter->private;
636 struct ring_buffer_iter *ring_iter = NULL;
637 struct ring_buffer_event *event;
638 struct ftrace_graph_ret_entry *next;
639
640 /*
641 * If the previous output failed to write to the seq buffer,
642 * then we just reuse the data from before.
643 */
644 if (data && data->failed) {
645 curr = &data->ent;
646 next = &data->ret;
647 } else {
648
649 ring_iter = trace_buffer_iter(iter, iter->cpu);
650
651 /* First peek to compare current entry and the next one */
652 if (ring_iter)
653 event = ring_buffer_iter_peek(ring_iter, NULL);
654 else {
655 /*
656 * We need to consume the current entry to see
657 * the next one.
658 */
659 ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu,
660 NULL, NULL);
661 event = ring_buffer_peek(iter->trace_buffer->buffer, iter->cpu,
662 NULL, NULL);
663 }
664
665 if (!event)
666 return NULL;
667
668 next = ring_buffer_event_data(event);
669
670 if (data) {
671 /*
672 * Save current and next entries for later reference
673 * if the output fails.
674 */
675 data->ent = *curr;
676 /*
677 * If the next event is not a return type, then
678 * we only care about what type it is. Otherwise we can
679 * safely copy the entire event.
680 */
681 if (next->ent.type == TRACE_GRAPH_RET)
682 data->ret = *next;
683 else
684 data->ret.ent.type = next->ent.type;
685 }
686 }
687
688 if (next->ent.type != TRACE_GRAPH_RET)
689 return NULL;
690
691 if (curr->ent.pid != next->ent.pid ||
692 curr->graph_ent.func != next->ret.func)
693 return NULL;
694
695 /* this is a leaf, now advance the iterator */
696 if (ring_iter)
697 ring_buffer_read(ring_iter, NULL);
698
699 return next;
700}
701
702static void print_graph_abs_time(u64 t, struct trace_seq *s)
703{
704 unsigned long usecs_rem;
705
706 usecs_rem = do_div(t, NSEC_PER_SEC);
707 usecs_rem /= 1000;
708
709 trace_seq_printf(s, "%5lu.%06lu | ",
710 (unsigned long)t, usecs_rem);
711}
712
713static void
714print_graph_irq(struct trace_iterator *iter, unsigned long addr,
715 enum trace_type type, int cpu, pid_t pid, u32 flags)
716{
717 struct trace_array *tr = iter->tr;
718 struct trace_seq *s = &iter->seq;
719 struct trace_entry *ent = iter->ent;
720
721 if (addr < (unsigned long)__irqentry_text_start ||
722 addr >= (unsigned long)__irqentry_text_end)
723 return;
724
725 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
726 /* Absolute time */
727 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
728 print_graph_abs_time(iter->ts, s);
729
730 /* Cpu */
731 if (flags & TRACE_GRAPH_PRINT_CPU)
732 print_graph_cpu(s, cpu);
733
734 /* Proc */
735 if (flags & TRACE_GRAPH_PRINT_PROC) {
736 print_graph_proc(s, pid);
737 trace_seq_puts(s, " | ");
738 }
739
740 /* Latency format */
741 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
742 print_graph_lat_fmt(s, ent);
743 }
744
745 /* No overhead */
746 print_graph_duration(tr, 0, s, flags | FLAGS_FILL_START);
747
748 if (type == TRACE_GRAPH_ENT)
749 trace_seq_puts(s, "==========>");
750 else
751 trace_seq_puts(s, "<==========");
752
753 print_graph_duration(tr, 0, s, flags | FLAGS_FILL_END);
754 trace_seq_putc(s, '\n');
755}
756
757void
758trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
759{
760 unsigned long nsecs_rem = do_div(duration, 1000);
761 /* log10(ULONG_MAX) + '\0' */
762 char usecs_str[21];
763 char nsecs_str[5];
764 int len;
765 int i;
766
767 sprintf(usecs_str, "%lu", (unsigned long) duration);
768
769 /* Print msecs */
770 trace_seq_printf(s, "%s", usecs_str);
771
772 len = strlen(usecs_str);
773
774 /* Print nsecs (we don't want to exceed 7 numbers) */
775 if (len < 7) {
776 size_t slen = min_t(size_t, sizeof(nsecs_str), 8UL - len);
777
778 snprintf(nsecs_str, slen, "%03lu", nsecs_rem);
779 trace_seq_printf(s, ".%s", nsecs_str);
780 len += strlen(nsecs_str) + 1;
781 }
782
783 trace_seq_puts(s, " us ");
784
785 /* Print remaining spaces to fit the row's width */
786 for (i = len; i < 8; i++)
787 trace_seq_putc(s, ' ');
788}
789
790static void
791print_graph_duration(struct trace_array *tr, unsigned long long duration,
792 struct trace_seq *s, u32 flags)
793{
794 if (!(flags & TRACE_GRAPH_PRINT_DURATION) ||
795 !(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
796 return;
797
798 /* No real adata, just filling the column with spaces */
799 switch (flags & TRACE_GRAPH_PRINT_FILL_MASK) {
800 case FLAGS_FILL_FULL:
801 trace_seq_puts(s, " | ");
802 return;
803 case FLAGS_FILL_START:
804 trace_seq_puts(s, " ");
805 return;
806 case FLAGS_FILL_END:
807 trace_seq_puts(s, " |");
808 return;
809 }
810
811 /* Signal a overhead of time execution to the output */
812 if (flags & TRACE_GRAPH_PRINT_OVERHEAD)
813 trace_seq_printf(s, "%c ", trace_find_mark(duration));
814 else
815 trace_seq_puts(s, " ");
816
817 trace_print_graph_duration(duration, s);
818 trace_seq_puts(s, "| ");
819}
820
821/* Case of a leaf function on its call entry */
822static enum print_line_t
823print_graph_entry_leaf(struct trace_iterator *iter,
824 struct ftrace_graph_ent_entry *entry,
825 struct ftrace_graph_ret_entry *ret_entry,
826 struct trace_seq *s, u32 flags)
827{
828 struct fgraph_data *data = iter->private;
829 struct trace_array *tr = iter->tr;
830 struct ftrace_graph_ret *graph_ret;
831 struct ftrace_graph_ent *call;
832 unsigned long long duration;
833 int i;
834
835 graph_ret = &ret_entry->ret;
836 call = &entry->graph_ent;
837 duration = graph_ret->rettime - graph_ret->calltime;
838
839 if (data) {
840 struct fgraph_cpu_data *cpu_data;
841 int cpu = iter->cpu;
842
843 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
844
845 /* If a graph tracer ignored set_graph_notrace */
846 if (call->depth < -1)
847 call->depth += FTRACE_NOTRACE_DEPTH;
848
849 /*
850 * Comments display at + 1 to depth. Since
851 * this is a leaf function, keep the comments
852 * equal to this depth.
853 */
854 cpu_data->depth = call->depth - 1;
855
856 /* No need to keep this function around for this depth */
857 if (call->depth < FTRACE_RETFUNC_DEPTH &&
858 !WARN_ON_ONCE(call->depth < 0))
859 cpu_data->enter_funcs[call->depth] = 0;
860 }
861
862 /* Overhead and duration */
863 print_graph_duration(tr, duration, s, flags);
864
865 /* Function */
866 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
867 trace_seq_putc(s, ' ');
868
869 trace_seq_printf(s, "%ps();\n", (void *)call->func);
870
871 return trace_handle_return(s);
872}
873
874static enum print_line_t
875print_graph_entry_nested(struct trace_iterator *iter,
876 struct ftrace_graph_ent_entry *entry,
877 struct trace_seq *s, int cpu, u32 flags)
878{
879 struct ftrace_graph_ent *call = &entry->graph_ent;
880 struct fgraph_data *data = iter->private;
881 struct trace_array *tr = iter->tr;
882 int i;
883
884 if (data) {
885 struct fgraph_cpu_data *cpu_data;
886 int cpu = iter->cpu;
887
888 /* If a graph tracer ignored set_graph_notrace */
889 if (call->depth < -1)
890 call->depth += FTRACE_NOTRACE_DEPTH;
891
892 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
893 cpu_data->depth = call->depth;
894
895 /* Save this function pointer to see if the exit matches */
896 if (call->depth < FTRACE_RETFUNC_DEPTH &&
897 !WARN_ON_ONCE(call->depth < 0))
898 cpu_data->enter_funcs[call->depth] = call->func;
899 }
900
901 /* No time */
902 print_graph_duration(tr, 0, s, flags | FLAGS_FILL_FULL);
903
904 /* Function */
905 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
906 trace_seq_putc(s, ' ');
907
908 trace_seq_printf(s, "%ps() {\n", (void *)call->func);
909
910 if (trace_seq_has_overflowed(s))
911 return TRACE_TYPE_PARTIAL_LINE;
912
913 /*
914 * we already consumed the current entry to check the next one
915 * and see if this is a leaf.
916 */
917 return TRACE_TYPE_NO_CONSUME;
918}
919
920static void
921print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
922 int type, unsigned long addr, u32 flags)
923{
924 struct fgraph_data *data = iter->private;
925 struct trace_entry *ent = iter->ent;
926 struct trace_array *tr = iter->tr;
927 int cpu = iter->cpu;
928
929 /* Pid */
930 verif_pid(s, ent->pid, cpu, data);
931
932 if (type)
933 /* Interrupt */
934 print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
935
936 if (!(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
937 return;
938
939 /* Absolute time */
940 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
941 print_graph_abs_time(iter->ts, s);
942
943 /* Cpu */
944 if (flags & TRACE_GRAPH_PRINT_CPU)
945 print_graph_cpu(s, cpu);
946
947 /* Proc */
948 if (flags & TRACE_GRAPH_PRINT_PROC) {
949 print_graph_proc(s, ent->pid);
950 trace_seq_puts(s, " | ");
951 }
952
953 /* Latency format */
954 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
955 print_graph_lat_fmt(s, ent);
956
957 return;
958}
959
960/*
961 * Entry check for irq code
962 *
963 * returns 1 if
964 * - we are inside irq code
965 * - we just entered irq code
966 *
967 * retunns 0 if
968 * - funcgraph-interrupts option is set
969 * - we are not inside irq code
970 */
971static int
972check_irq_entry(struct trace_iterator *iter, u32 flags,
973 unsigned long addr, int depth)
974{
975 int cpu = iter->cpu;
976 int *depth_irq;
977 struct fgraph_data *data = iter->private;
978
979 /*
980 * If we are either displaying irqs, or we got called as
981 * a graph event and private data does not exist,
982 * then we bypass the irq check.
983 */
984 if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
985 (!data))
986 return 0;
987
988 depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
989
990 /*
991 * We are inside the irq code
992 */
993 if (*depth_irq >= 0)
994 return 1;
995
996 if ((addr < (unsigned long)__irqentry_text_start) ||
997 (addr >= (unsigned long)__irqentry_text_end))
998 return 0;
999
1000 /*
1001 * We are entering irq code.
1002 */
1003 *depth_irq = depth;
1004 return 1;
1005}
1006
1007/*
1008 * Return check for irq code
1009 *
1010 * returns 1 if
1011 * - we are inside irq code
1012 * - we just left irq code
1013 *
1014 * returns 0 if
1015 * - funcgraph-interrupts option is set
1016 * - we are not inside irq code
1017 */
1018static int
1019check_irq_return(struct trace_iterator *iter, u32 flags, int depth)
1020{
1021 int cpu = iter->cpu;
1022 int *depth_irq;
1023 struct fgraph_data *data = iter->private;
1024
1025 /*
1026 * If we are either displaying irqs, or we got called as
1027 * a graph event and private data does not exist,
1028 * then we bypass the irq check.
1029 */
1030 if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
1031 (!data))
1032 return 0;
1033
1034 depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1035
1036 /*
1037 * We are not inside the irq code.
1038 */
1039 if (*depth_irq == -1)
1040 return 0;
1041
1042 /*
1043 * We are inside the irq code, and this is returning entry.
1044 * Let's not trace it and clear the entry depth, since
1045 * we are out of irq code.
1046 *
1047 * This condition ensures that we 'leave the irq code' once
1048 * we are out of the entry depth. Thus protecting us from
1049 * the RETURN entry loss.
1050 */
1051 if (*depth_irq >= depth) {
1052 *depth_irq = -1;
1053 return 1;
1054 }
1055
1056 /*
1057 * We are inside the irq code, and this is not the entry.
1058 */
1059 return 1;
1060}
1061
1062static enum print_line_t
1063print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
1064 struct trace_iterator *iter, u32 flags)
1065{
1066 struct fgraph_data *data = iter->private;
1067 struct ftrace_graph_ent *call = &field->graph_ent;
1068 struct ftrace_graph_ret_entry *leaf_ret;
1069 static enum print_line_t ret;
1070 int cpu = iter->cpu;
1071
1072 if (check_irq_entry(iter, flags, call->func, call->depth))
1073 return TRACE_TYPE_HANDLED;
1074
1075 print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags);
1076
1077 leaf_ret = get_return_for_leaf(iter, field);
1078 if (leaf_ret)
1079 ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags);
1080 else
1081 ret = print_graph_entry_nested(iter, field, s, cpu, flags);
1082
1083 if (data) {
1084 /*
1085 * If we failed to write our output, then we need to make
1086 * note of it. Because we already consumed our entry.
1087 */
1088 if (s->full) {
1089 data->failed = 1;
1090 data->cpu = cpu;
1091 } else
1092 data->failed = 0;
1093 }
1094
1095 return ret;
1096}
1097
1098static enum print_line_t
1099print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
1100 struct trace_entry *ent, struct trace_iterator *iter,
1101 u32 flags)
1102{
1103 unsigned long long duration = trace->rettime - trace->calltime;
1104 struct fgraph_data *data = iter->private;
1105 struct trace_array *tr = iter->tr;
1106 pid_t pid = ent->pid;
1107 int cpu = iter->cpu;
1108 int func_match = 1;
1109 int i;
1110
1111 if (check_irq_return(iter, flags, trace->depth))
1112 return TRACE_TYPE_HANDLED;
1113
1114 if (data) {
1115 struct fgraph_cpu_data *cpu_data;
1116 int cpu = iter->cpu;
1117
1118 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
1119
1120 /*
1121 * Comments display at + 1 to depth. This is the
1122 * return from a function, we now want the comments
1123 * to display at the same level of the bracket.
1124 */
1125 cpu_data->depth = trace->depth - 1;
1126
1127 if (trace->depth < FTRACE_RETFUNC_DEPTH &&
1128 !WARN_ON_ONCE(trace->depth < 0)) {
1129 if (cpu_data->enter_funcs[trace->depth] != trace->func)
1130 func_match = 0;
1131 cpu_data->enter_funcs[trace->depth] = 0;
1132 }
1133 }
1134
1135 print_graph_prologue(iter, s, 0, 0, flags);
1136
1137 /* Overhead and duration */
1138 print_graph_duration(tr, duration, s, flags);
1139
1140 /* Closing brace */
1141 for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++)
1142 trace_seq_putc(s, ' ');
1143
1144 /*
1145 * If the return function does not have a matching entry,
1146 * then the entry was lost. Instead of just printing
1147 * the '}' and letting the user guess what function this
1148 * belongs to, write out the function name. Always do
1149 * that if the funcgraph-tail option is enabled.
1150 */
1151 if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL))
1152 trace_seq_puts(s, "}\n");
1153 else
1154 trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
1155
1156 /* Overrun */
1157 if (flags & TRACE_GRAPH_PRINT_OVERRUN)
1158 trace_seq_printf(s, " (Overruns: %lu)\n",
1159 trace->overrun);
1160
1161 print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
1162 cpu, pid, flags);
1163
1164 return trace_handle_return(s);
1165}
1166
1167static enum print_line_t
1168print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
1169 struct trace_iterator *iter, u32 flags)
1170{
1171 struct trace_array *tr = iter->tr;
1172 unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
1173 struct fgraph_data *data = iter->private;
1174 struct trace_event *event;
1175 int depth = 0;
1176 int ret;
1177 int i;
1178
1179 if (data)
1180 depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
1181
1182 print_graph_prologue(iter, s, 0, 0, flags);
1183
1184 /* No time */
1185 print_graph_duration(tr, 0, s, flags | FLAGS_FILL_FULL);
1186
1187 /* Indentation */
1188 if (depth > 0)
1189 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++)
1190 trace_seq_putc(s, ' ');
1191
1192 /* The comment */
1193 trace_seq_puts(s, "/* ");
1194
1195 switch (iter->ent->type) {
1196 case TRACE_BPUTS:
1197 ret = trace_print_bputs_msg_only(iter);
1198 if (ret != TRACE_TYPE_HANDLED)
1199 return ret;
1200 break;
1201 case TRACE_BPRINT:
1202 ret = trace_print_bprintk_msg_only(iter);
1203 if (ret != TRACE_TYPE_HANDLED)
1204 return ret;
1205 break;
1206 case TRACE_PRINT:
1207 ret = trace_print_printk_msg_only(iter);
1208 if (ret != TRACE_TYPE_HANDLED)
1209 return ret;
1210 break;
1211 default:
1212 event = ftrace_find_event(ent->type);
1213 if (!event)
1214 return TRACE_TYPE_UNHANDLED;
1215
1216 ret = event->funcs->trace(iter, sym_flags, event);
1217 if (ret != TRACE_TYPE_HANDLED)
1218 return ret;
1219 }
1220
1221 if (trace_seq_has_overflowed(s))
1222 goto out;
1223
1224 /* Strip ending newline */
1225 if (s->buffer[s->seq.len - 1] == '\n') {
1226 s->buffer[s->seq.len - 1] = '\0';
1227 s->seq.len--;
1228 }
1229
1230 trace_seq_puts(s, " */\n");
1231 out:
1232 return trace_handle_return(s);
1233}
1234
1235
1236enum print_line_t
1237print_graph_function_flags(struct trace_iterator *iter, u32 flags)
1238{
1239 struct ftrace_graph_ent_entry *field;
1240 struct fgraph_data *data = iter->private;
1241 struct trace_entry *entry = iter->ent;
1242 struct trace_seq *s = &iter->seq;
1243 int cpu = iter->cpu;
1244 int ret;
1245
1246 if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
1247 per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
1248 return TRACE_TYPE_HANDLED;
1249 }
1250
1251 /*
1252 * If the last output failed, there's a possibility we need
1253 * to print out the missing entry which would never go out.
1254 */
1255 if (data && data->failed) {
1256 field = &data->ent;
1257 iter->cpu = data->cpu;
1258 ret = print_graph_entry(field, s, iter, flags);
1259 if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
1260 per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
1261 ret = TRACE_TYPE_NO_CONSUME;
1262 }
1263 iter->cpu = cpu;
1264 return ret;
1265 }
1266
1267 switch (entry->type) {
1268 case TRACE_GRAPH_ENT: {
1269 /*
1270 * print_graph_entry() may consume the current event,
1271 * thus @field may become invalid, so we need to save it.
1272 * sizeof(struct ftrace_graph_ent_entry) is very small,
1273 * it can be safely saved at the stack.
1274 */
1275 struct ftrace_graph_ent_entry saved;
1276 trace_assign_type(field, entry);
1277 saved = *field;
1278 return print_graph_entry(&saved, s, iter, flags);
1279 }
1280 case TRACE_GRAPH_RET: {
1281 struct ftrace_graph_ret_entry *field;
1282 trace_assign_type(field, entry);
1283 return print_graph_return(&field->ret, s, entry, iter, flags);
1284 }
1285 case TRACE_STACK:
1286 case TRACE_FN:
1287 /* dont trace stack and functions as comments */
1288 return TRACE_TYPE_UNHANDLED;
1289
1290 default:
1291 return print_graph_comment(s, entry, iter, flags);
1292 }
1293
1294 return TRACE_TYPE_HANDLED;
1295}
1296
1297static enum print_line_t
1298print_graph_function(struct trace_iterator *iter)
1299{
1300 return print_graph_function_flags(iter, tracer_flags.val);
1301}
1302
1303static enum print_line_t
1304print_graph_function_event(struct trace_iterator *iter, int flags,
1305 struct trace_event *event)
1306{
1307 return print_graph_function(iter);
1308}
1309
1310static void print_lat_header(struct seq_file *s, u32 flags)
1311{
1312 static const char spaces[] = " " /* 16 spaces */
1313 " " /* 4 spaces */
1314 " "; /* 17 spaces */
1315 int size = 0;
1316
1317 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1318 size += 16;
1319 if (flags & TRACE_GRAPH_PRINT_CPU)
1320 size += 4;
1321 if (flags & TRACE_GRAPH_PRINT_PROC)
1322 size += 17;
1323
1324 seq_printf(s, "#%.*s _-----=> irqs-off \n", size, spaces);
1325 seq_printf(s, "#%.*s / _----=> need-resched \n", size, spaces);
1326 seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
1327 seq_printf(s, "#%.*s|| / _--=> preempt-depth \n", size, spaces);
1328 seq_printf(s, "#%.*s||| / \n", size, spaces);
1329}
1330
1331static void __print_graph_headers_flags(struct trace_array *tr,
1332 struct seq_file *s, u32 flags)
1333{
1334 int lat = tr->trace_flags & TRACE_ITER_LATENCY_FMT;
1335
1336 if (lat)
1337 print_lat_header(s, flags);
1338
1339 /* 1st line */
1340 seq_putc(s, '#');
1341 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1342 seq_puts(s, " TIME ");
1343 if (flags & TRACE_GRAPH_PRINT_CPU)
1344 seq_puts(s, " CPU");
1345 if (flags & TRACE_GRAPH_PRINT_PROC)
1346 seq_puts(s, " TASK/PID ");
1347 if (lat)
1348 seq_puts(s, "||||");
1349 if (flags & TRACE_GRAPH_PRINT_DURATION)
1350 seq_puts(s, " DURATION ");
1351 seq_puts(s, " FUNCTION CALLS\n");
1352
1353 /* 2nd line */
1354 seq_putc(s, '#');
1355 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1356 seq_puts(s, " | ");
1357 if (flags & TRACE_GRAPH_PRINT_CPU)
1358 seq_puts(s, " | ");
1359 if (flags & TRACE_GRAPH_PRINT_PROC)
1360 seq_puts(s, " | | ");
1361 if (lat)
1362 seq_puts(s, "||||");
1363 if (flags & TRACE_GRAPH_PRINT_DURATION)
1364 seq_puts(s, " | | ");
1365 seq_puts(s, " | | | |\n");
1366}
1367
1368static void print_graph_headers(struct seq_file *s)
1369{
1370 print_graph_headers_flags(s, tracer_flags.val);
1371}
1372
1373void print_graph_headers_flags(struct seq_file *s, u32 flags)
1374{
1375 struct trace_iterator *iter = s->private;
1376 struct trace_array *tr = iter->tr;
1377
1378 if (!(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
1379 return;
1380
1381 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT) {
1382 /* print nothing if the buffers are empty */
1383 if (trace_empty(iter))
1384 return;
1385
1386 print_trace_header(s, iter);
1387 }
1388
1389 __print_graph_headers_flags(tr, s, flags);
1390}
1391
1392void graph_trace_open(struct trace_iterator *iter)
1393{
1394 /* pid and depth on the last trace processed */
1395 struct fgraph_data *data;
1396 gfp_t gfpflags;
1397 int cpu;
1398
1399 iter->private = NULL;
1400
1401 /* We can be called in atomic context via ftrace_dump() */
1402 gfpflags = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL;
1403
1404 data = kzalloc(sizeof(*data), gfpflags);
1405 if (!data)
1406 goto out_err;
1407
1408 data->cpu_data = alloc_percpu_gfp(struct fgraph_cpu_data, gfpflags);
1409 if (!data->cpu_data)
1410 goto out_err_free;
1411
1412 for_each_possible_cpu(cpu) {
1413 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
1414 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
1415 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
1416 int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1417
1418 *pid = -1;
1419 *depth = 0;
1420 *ignore = 0;
1421 *depth_irq = -1;
1422 }
1423
1424 iter->private = data;
1425
1426 return;
1427
1428 out_err_free:
1429 kfree(data);
1430 out_err:
1431 pr_warn("function graph tracer: not enough memory\n");
1432}
1433
1434void graph_trace_close(struct trace_iterator *iter)
1435{
1436 struct fgraph_data *data = iter->private;
1437
1438 if (data) {
1439 free_percpu(data->cpu_data);
1440 kfree(data);
1441 }
1442}
1443
1444static int
1445func_graph_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1446{
1447 if (bit == TRACE_GRAPH_PRINT_IRQS)
1448 ftrace_graph_skip_irqs = !set;
1449
1450 if (bit == TRACE_GRAPH_SLEEP_TIME)
1451 ftrace_graph_sleep_time_control(set);
1452
1453 if (bit == TRACE_GRAPH_GRAPH_TIME)
1454 ftrace_graph_graph_time_control(set);
1455
1456 return 0;
1457}
1458
1459static struct trace_event_functions graph_functions = {
1460 .trace = print_graph_function_event,
1461};
1462
1463static struct trace_event graph_trace_entry_event = {
1464 .type = TRACE_GRAPH_ENT,
1465 .funcs = &graph_functions,
1466};
1467
1468static struct trace_event graph_trace_ret_event = {
1469 .type = TRACE_GRAPH_RET,
1470 .funcs = &graph_functions
1471};
1472
1473static struct tracer graph_trace __tracer_data = {
1474 .name = "function_graph",
1475 .update_thresh = graph_trace_update_thresh,
1476 .open = graph_trace_open,
1477 .pipe_open = graph_trace_open,
1478 .close = graph_trace_close,
1479 .pipe_close = graph_trace_close,
1480 .init = graph_trace_init,
1481 .reset = graph_trace_reset,
1482 .print_line = print_graph_function,
1483 .print_header = print_graph_headers,
1484 .flags = &tracer_flags,
1485 .set_flag = func_graph_set_flag,
1486#ifdef CONFIG_FTRACE_SELFTEST
1487 .selftest = trace_selftest_startup_function_graph,
1488#endif
1489};
1490
1491
1492static ssize_t
1493graph_depth_write(struct file *filp, const char __user *ubuf, size_t cnt,
1494 loff_t *ppos)
1495{
1496 unsigned long val;
1497 int ret;
1498
1499 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1500 if (ret)
1501 return ret;
1502
1503 fgraph_max_depth = val;
1504
1505 *ppos += cnt;
1506
1507 return cnt;
1508}
1509
1510static ssize_t
1511graph_depth_read(struct file *filp, char __user *ubuf, size_t cnt,
1512 loff_t *ppos)
1513{
1514 char buf[15]; /* More than enough to hold UINT_MAX + "\n"*/
1515 int n;
1516
1517 n = sprintf(buf, "%d\n", fgraph_max_depth);
1518
1519 return simple_read_from_buffer(ubuf, cnt, ppos, buf, n);
1520}
1521
1522static const struct file_operations graph_depth_fops = {
1523 .open = tracing_open_generic,
1524 .write = graph_depth_write,
1525 .read = graph_depth_read,
1526 .llseek = generic_file_llseek,
1527};
1528
1529static __init int init_graph_tracefs(void)
1530{
1531 struct dentry *d_tracer;
1532
1533 d_tracer = tracing_init_dentry();
1534 if (IS_ERR(d_tracer))
1535 return 0;
1536
1537 trace_create_file("max_graph_depth", 0644, d_tracer,
1538 NULL, &graph_depth_fops);
1539
1540 return 0;
1541}
1542fs_initcall(init_graph_tracefs);
1543
1544static __init int init_graph_trace(void)
1545{
1546 max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);
1547
1548 if (!register_trace_event(&graph_trace_entry_event)) {
1549 pr_warn("Warning: could not register graph trace events\n");
1550 return 1;
1551 }
1552
1553 if (!register_trace_event(&graph_trace_ret_event)) {
1554 pr_warn("Warning: could not register graph trace events\n");
1555 return 1;
1556 }
1557
1558 return register_tracer(&graph_trace);
1559}
1560
1561core_initcall(init_graph_trace);