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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#ifdef CONFIG_FUNCTION_GRAPH_RETVAL
62 /* Display function return value ? */
63 { TRACER_OPT(funcgraph-retval, TRACE_GRAPH_PRINT_RETVAL) },
64 /* Display function return value in hexadecimal format ? */
65 { TRACER_OPT(funcgraph-retval-hex, TRACE_GRAPH_PRINT_RETVAL_HEX) },
66#endif
67 /* Include sleep time (scheduled out) between entry and return */
68 { TRACER_OPT(sleep-time, TRACE_GRAPH_SLEEP_TIME) },
69
70#ifdef CONFIG_FUNCTION_PROFILER
71 /* Include time within nested functions */
72 { TRACER_OPT(graph-time, TRACE_GRAPH_GRAPH_TIME) },
73#endif
74
75 { } /* Empty entry */
76};
77
78static struct tracer_flags tracer_flags = {
79 /* Don't display overruns, proc, or tail by default */
80 .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
81 TRACE_GRAPH_PRINT_DURATION | TRACE_GRAPH_PRINT_IRQS |
82 TRACE_GRAPH_SLEEP_TIME | TRACE_GRAPH_GRAPH_TIME,
83 .opts = trace_opts
84};
85
86static struct trace_array *graph_array;
87
88/*
89 * DURATION column is being also used to display IRQ signs,
90 * following values are used by print_graph_irq and others
91 * to fill in space into DURATION column.
92 */
93enum {
94 FLAGS_FILL_FULL = 1 << TRACE_GRAPH_PRINT_FILL_SHIFT,
95 FLAGS_FILL_START = 2 << TRACE_GRAPH_PRINT_FILL_SHIFT,
96 FLAGS_FILL_END = 3 << TRACE_GRAPH_PRINT_FILL_SHIFT,
97};
98
99static void
100print_graph_duration(struct trace_array *tr, unsigned long long duration,
101 struct trace_seq *s, u32 flags);
102
103int __trace_graph_entry(struct trace_array *tr,
104 struct ftrace_graph_ent *trace,
105 unsigned int trace_ctx)
106{
107 struct trace_event_call *call = &event_funcgraph_entry;
108 struct ring_buffer_event *event;
109 struct trace_buffer *buffer = tr->array_buffer.buffer;
110 struct ftrace_graph_ent_entry *entry;
111
112 event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
113 sizeof(*entry), trace_ctx);
114 if (!event)
115 return 0;
116 entry = ring_buffer_event_data(event);
117 entry->graph_ent = *trace;
118 if (!call_filter_check_discard(call, entry, buffer, event))
119 trace_buffer_unlock_commit_nostack(buffer, event);
120
121 return 1;
122}
123
124static inline int ftrace_graph_ignore_irqs(void)
125{
126 if (!ftrace_graph_skip_irqs || trace_recursion_test(TRACE_IRQ_BIT))
127 return 0;
128
129 return in_hardirq();
130}
131
132int trace_graph_entry(struct ftrace_graph_ent *trace)
133{
134 struct trace_array *tr = graph_array;
135 struct trace_array_cpu *data;
136 unsigned long flags;
137 unsigned int trace_ctx;
138 long disabled;
139 int ret;
140 int cpu;
141
142 if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT))
143 return 0;
144
145 /*
146 * Do not trace a function if it's filtered by set_graph_notrace.
147 * Make the index of ret stack negative to indicate that it should
148 * ignore further functions. But it needs its own ret stack entry
149 * to recover the original index in order to continue tracing after
150 * returning from the function.
151 */
152 if (ftrace_graph_notrace_addr(trace->func)) {
153 trace_recursion_set(TRACE_GRAPH_NOTRACE_BIT);
154 /*
155 * Need to return 1 to have the return called
156 * that will clear the NOTRACE bit.
157 */
158 return 1;
159 }
160
161 if (!ftrace_trace_task(tr))
162 return 0;
163
164 if (ftrace_graph_ignore_func(trace))
165 return 0;
166
167 if (ftrace_graph_ignore_irqs())
168 return 0;
169
170 /*
171 * Stop here if tracing_threshold is set. We only write function return
172 * events to the ring buffer.
173 */
174 if (tracing_thresh)
175 return 1;
176
177 local_irq_save(flags);
178 cpu = raw_smp_processor_id();
179 data = per_cpu_ptr(tr->array_buffer.data, cpu);
180 disabled = atomic_inc_return(&data->disabled);
181 if (likely(disabled == 1)) {
182 trace_ctx = tracing_gen_ctx_flags(flags);
183 ret = __trace_graph_entry(tr, trace, trace_ctx);
184 } else {
185 ret = 0;
186 }
187
188 atomic_dec(&data->disabled);
189 local_irq_restore(flags);
190
191 return ret;
192}
193
194static void
195__trace_graph_function(struct trace_array *tr,
196 unsigned long ip, unsigned int trace_ctx)
197{
198 u64 time = trace_clock_local();
199 struct ftrace_graph_ent ent = {
200 .func = ip,
201 .depth = 0,
202 };
203 struct ftrace_graph_ret ret = {
204 .func = ip,
205 .depth = 0,
206 .calltime = time,
207 .rettime = time,
208 };
209
210 __trace_graph_entry(tr, &ent, trace_ctx);
211 __trace_graph_return(tr, &ret, trace_ctx);
212}
213
214void
215trace_graph_function(struct trace_array *tr,
216 unsigned long ip, unsigned long parent_ip,
217 unsigned int trace_ctx)
218{
219 __trace_graph_function(tr, ip, trace_ctx);
220}
221
222void __trace_graph_return(struct trace_array *tr,
223 struct ftrace_graph_ret *trace,
224 unsigned int trace_ctx)
225{
226 struct trace_event_call *call = &event_funcgraph_exit;
227 struct ring_buffer_event *event;
228 struct trace_buffer *buffer = tr->array_buffer.buffer;
229 struct ftrace_graph_ret_entry *entry;
230
231 event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
232 sizeof(*entry), trace_ctx);
233 if (!event)
234 return;
235 entry = ring_buffer_event_data(event);
236 entry->ret = *trace;
237 if (!call_filter_check_discard(call, entry, buffer, event))
238 trace_buffer_unlock_commit_nostack(buffer, event);
239}
240
241void trace_graph_return(struct ftrace_graph_ret *trace)
242{
243 struct trace_array *tr = graph_array;
244 struct trace_array_cpu *data;
245 unsigned long flags;
246 unsigned int trace_ctx;
247 long disabled;
248 int cpu;
249
250 ftrace_graph_addr_finish(trace);
251
252 if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
253 trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
254 return;
255 }
256
257 local_irq_save(flags);
258 cpu = raw_smp_processor_id();
259 data = per_cpu_ptr(tr->array_buffer.data, cpu);
260 disabled = atomic_inc_return(&data->disabled);
261 if (likely(disabled == 1)) {
262 trace_ctx = tracing_gen_ctx_flags(flags);
263 __trace_graph_return(tr, trace, trace_ctx);
264 }
265 atomic_dec(&data->disabled);
266 local_irq_restore(flags);
267}
268
269void set_graph_array(struct trace_array *tr)
270{
271 graph_array = tr;
272
273 /* Make graph_array visible before we start tracing */
274
275 smp_mb();
276}
277
278static void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
279{
280 ftrace_graph_addr_finish(trace);
281
282 if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
283 trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
284 return;
285 }
286
287 if (tracing_thresh &&
288 (trace->rettime - trace->calltime < tracing_thresh))
289 return;
290 else
291 trace_graph_return(trace);
292}
293
294static struct fgraph_ops funcgraph_thresh_ops = {
295 .entryfunc = &trace_graph_entry,
296 .retfunc = &trace_graph_thresh_return,
297};
298
299static struct fgraph_ops funcgraph_ops = {
300 .entryfunc = &trace_graph_entry,
301 .retfunc = &trace_graph_return,
302};
303
304static int graph_trace_init(struct trace_array *tr)
305{
306 int ret;
307
308 set_graph_array(tr);
309 if (tracing_thresh)
310 ret = register_ftrace_graph(&funcgraph_thresh_ops);
311 else
312 ret = register_ftrace_graph(&funcgraph_ops);
313 if (ret)
314 return ret;
315 tracing_start_cmdline_record();
316
317 return 0;
318}
319
320static void graph_trace_reset(struct trace_array *tr)
321{
322 tracing_stop_cmdline_record();
323 if (tracing_thresh)
324 unregister_ftrace_graph(&funcgraph_thresh_ops);
325 else
326 unregister_ftrace_graph(&funcgraph_ops);
327}
328
329static int graph_trace_update_thresh(struct trace_array *tr)
330{
331 graph_trace_reset(tr);
332 return graph_trace_init(tr);
333}
334
335static int max_bytes_for_cpu;
336
337static void print_graph_cpu(struct trace_seq *s, int cpu)
338{
339 /*
340 * Start with a space character - to make it stand out
341 * to the right a bit when trace output is pasted into
342 * email:
343 */
344 trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
345}
346
347#define TRACE_GRAPH_PROCINFO_LENGTH 14
348
349static void print_graph_proc(struct trace_seq *s, pid_t pid)
350{
351 char comm[TASK_COMM_LEN];
352 /* sign + log10(MAX_INT) + '\0' */
353 char pid_str[11];
354 int spaces = 0;
355 int len;
356 int i;
357
358 trace_find_cmdline(pid, comm);
359 comm[7] = '\0';
360 sprintf(pid_str, "%d", pid);
361
362 /* 1 stands for the "-" character */
363 len = strlen(comm) + strlen(pid_str) + 1;
364
365 if (len < TRACE_GRAPH_PROCINFO_LENGTH)
366 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
367
368 /* First spaces to align center */
369 for (i = 0; i < spaces / 2; i++)
370 trace_seq_putc(s, ' ');
371
372 trace_seq_printf(s, "%s-%s", comm, pid_str);
373
374 /* Last spaces to align center */
375 for (i = 0; i < spaces - (spaces / 2); i++)
376 trace_seq_putc(s, ' ');
377}
378
379
380static void print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
381{
382 trace_seq_putc(s, ' ');
383 trace_print_lat_fmt(s, entry);
384 trace_seq_puts(s, " | ");
385}
386
387/* If the pid changed since the last trace, output this event */
388static void
389verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
390{
391 pid_t prev_pid;
392 pid_t *last_pid;
393
394 if (!data)
395 return;
396
397 last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
398
399 if (*last_pid == pid)
400 return;
401
402 prev_pid = *last_pid;
403 *last_pid = pid;
404
405 if (prev_pid == -1)
406 return;
407/*
408 * Context-switch trace line:
409
410 ------------------------------------------
411 | 1) migration/0--1 => sshd-1755
412 ------------------------------------------
413
414 */
415 trace_seq_puts(s, " ------------------------------------------\n");
416 print_graph_cpu(s, cpu);
417 print_graph_proc(s, prev_pid);
418 trace_seq_puts(s, " => ");
419 print_graph_proc(s, pid);
420 trace_seq_puts(s, "\n ------------------------------------------\n\n");
421}
422
423static struct ftrace_graph_ret_entry *
424get_return_for_leaf(struct trace_iterator *iter,
425 struct ftrace_graph_ent_entry *curr)
426{
427 struct fgraph_data *data = iter->private;
428 struct ring_buffer_iter *ring_iter = NULL;
429 struct ring_buffer_event *event;
430 struct ftrace_graph_ret_entry *next;
431
432 /*
433 * If the previous output failed to write to the seq buffer,
434 * then we just reuse the data from before.
435 */
436 if (data && data->failed) {
437 curr = &data->ent;
438 next = &data->ret;
439 } else {
440
441 ring_iter = trace_buffer_iter(iter, iter->cpu);
442
443 /* First peek to compare current entry and the next one */
444 if (ring_iter)
445 event = ring_buffer_iter_peek(ring_iter, NULL);
446 else {
447 /*
448 * We need to consume the current entry to see
449 * the next one.
450 */
451 ring_buffer_consume(iter->array_buffer->buffer, iter->cpu,
452 NULL, NULL);
453 event = ring_buffer_peek(iter->array_buffer->buffer, iter->cpu,
454 NULL, NULL);
455 }
456
457 if (!event)
458 return NULL;
459
460 next = ring_buffer_event_data(event);
461
462 if (data) {
463 /*
464 * Save current and next entries for later reference
465 * if the output fails.
466 */
467 data->ent = *curr;
468 /*
469 * If the next event is not a return type, then
470 * we only care about what type it is. Otherwise we can
471 * safely copy the entire event.
472 */
473 if (next->ent.type == TRACE_GRAPH_RET)
474 data->ret = *next;
475 else
476 data->ret.ent.type = next->ent.type;
477 }
478 }
479
480 if (next->ent.type != TRACE_GRAPH_RET)
481 return NULL;
482
483 if (curr->ent.pid != next->ent.pid ||
484 curr->graph_ent.func != next->ret.func)
485 return NULL;
486
487 /* this is a leaf, now advance the iterator */
488 if (ring_iter)
489 ring_buffer_iter_advance(ring_iter);
490
491 return next;
492}
493
494static void print_graph_abs_time(u64 t, struct trace_seq *s)
495{
496 unsigned long usecs_rem;
497
498 usecs_rem = do_div(t, NSEC_PER_SEC);
499 usecs_rem /= 1000;
500
501 trace_seq_printf(s, "%5lu.%06lu | ",
502 (unsigned long)t, usecs_rem);
503}
504
505static void
506print_graph_rel_time(struct trace_iterator *iter, struct trace_seq *s)
507{
508 unsigned long long usecs;
509
510 usecs = iter->ts - iter->array_buffer->time_start;
511 do_div(usecs, NSEC_PER_USEC);
512
513 trace_seq_printf(s, "%9llu us | ", usecs);
514}
515
516static void
517print_graph_irq(struct trace_iterator *iter, unsigned long addr,
518 enum trace_type type, int cpu, pid_t pid, u32 flags)
519{
520 struct trace_array *tr = iter->tr;
521 struct trace_seq *s = &iter->seq;
522 struct trace_entry *ent = iter->ent;
523
524 if (addr < (unsigned long)__irqentry_text_start ||
525 addr >= (unsigned long)__irqentry_text_end)
526 return;
527
528 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
529 /* Absolute time */
530 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
531 print_graph_abs_time(iter->ts, s);
532
533 /* Relative time */
534 if (flags & TRACE_GRAPH_PRINT_REL_TIME)
535 print_graph_rel_time(iter, s);
536
537 /* Cpu */
538 if (flags & TRACE_GRAPH_PRINT_CPU)
539 print_graph_cpu(s, cpu);
540
541 /* Proc */
542 if (flags & TRACE_GRAPH_PRINT_PROC) {
543 print_graph_proc(s, pid);
544 trace_seq_puts(s, " | ");
545 }
546
547 /* Latency format */
548 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
549 print_graph_lat_fmt(s, ent);
550 }
551
552 /* No overhead */
553 print_graph_duration(tr, 0, s, flags | FLAGS_FILL_START);
554
555 if (type == TRACE_GRAPH_ENT)
556 trace_seq_puts(s, "==========>");
557 else
558 trace_seq_puts(s, "<==========");
559
560 print_graph_duration(tr, 0, s, flags | FLAGS_FILL_END);
561 trace_seq_putc(s, '\n');
562}
563
564void
565trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
566{
567 unsigned long nsecs_rem = do_div(duration, 1000);
568 /* log10(ULONG_MAX) + '\0' */
569 char usecs_str[21];
570 char nsecs_str[5];
571 int len;
572 int i;
573
574 sprintf(usecs_str, "%lu", (unsigned long) duration);
575
576 /* Print msecs */
577 trace_seq_printf(s, "%s", usecs_str);
578
579 len = strlen(usecs_str);
580
581 /* Print nsecs (we don't want to exceed 7 numbers) */
582 if (len < 7) {
583 size_t slen = min_t(size_t, sizeof(nsecs_str), 8UL - len);
584
585 snprintf(nsecs_str, slen, "%03lu", nsecs_rem);
586 trace_seq_printf(s, ".%s", nsecs_str);
587 len += strlen(nsecs_str) + 1;
588 }
589
590 trace_seq_puts(s, " us ");
591
592 /* Print remaining spaces to fit the row's width */
593 for (i = len; i < 8; i++)
594 trace_seq_putc(s, ' ');
595}
596
597static void
598print_graph_duration(struct trace_array *tr, unsigned long long duration,
599 struct trace_seq *s, u32 flags)
600{
601 if (!(flags & TRACE_GRAPH_PRINT_DURATION) ||
602 !(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
603 return;
604
605 /* No real adata, just filling the column with spaces */
606 switch (flags & TRACE_GRAPH_PRINT_FILL_MASK) {
607 case FLAGS_FILL_FULL:
608 trace_seq_puts(s, " | ");
609 return;
610 case FLAGS_FILL_START:
611 trace_seq_puts(s, " ");
612 return;
613 case FLAGS_FILL_END:
614 trace_seq_puts(s, " |");
615 return;
616 }
617
618 /* Signal a overhead of time execution to the output */
619 if (flags & TRACE_GRAPH_PRINT_OVERHEAD)
620 trace_seq_printf(s, "%c ", trace_find_mark(duration));
621 else
622 trace_seq_puts(s, " ");
623
624 trace_print_graph_duration(duration, s);
625 trace_seq_puts(s, "| ");
626}
627
628#ifdef CONFIG_FUNCTION_GRAPH_RETVAL
629
630#define __TRACE_GRAPH_PRINT_RETVAL TRACE_GRAPH_PRINT_RETVAL
631
632static void print_graph_retval(struct trace_seq *s, unsigned long retval,
633 bool leaf, void *func, bool hex_format)
634{
635 unsigned long err_code = 0;
636
637 if (retval == 0 || hex_format)
638 goto done;
639
640 /* Check if the return value matches the negative format */
641 if (IS_ENABLED(CONFIG_64BIT) && (retval & BIT(31)) &&
642 (((u64)retval) >> 32) == 0) {
643 /* sign extension */
644 err_code = (unsigned long)(s32)retval;
645 } else {
646 err_code = retval;
647 }
648
649 if (!IS_ERR_VALUE(err_code))
650 err_code = 0;
651
652done:
653 if (leaf) {
654 if (hex_format || (err_code == 0))
655 trace_seq_printf(s, "%ps(); /* = 0x%lx */\n",
656 func, retval);
657 else
658 trace_seq_printf(s, "%ps(); /* = %ld */\n",
659 func, err_code);
660 } else {
661 if (hex_format || (err_code == 0))
662 trace_seq_printf(s, "} /* %ps = 0x%lx */\n",
663 func, retval);
664 else
665 trace_seq_printf(s, "} /* %ps = %ld */\n",
666 func, err_code);
667 }
668}
669
670#else
671
672#define __TRACE_GRAPH_PRINT_RETVAL 0
673
674#define print_graph_retval(_seq, _retval, _leaf, _func, _format) do {} while (0)
675
676#endif
677
678/* Case of a leaf function on its call entry */
679static enum print_line_t
680print_graph_entry_leaf(struct trace_iterator *iter,
681 struct ftrace_graph_ent_entry *entry,
682 struct ftrace_graph_ret_entry *ret_entry,
683 struct trace_seq *s, u32 flags)
684{
685 struct fgraph_data *data = iter->private;
686 struct trace_array *tr = iter->tr;
687 struct ftrace_graph_ret *graph_ret;
688 struct ftrace_graph_ent *call;
689 unsigned long long duration;
690 int cpu = iter->cpu;
691 int i;
692
693 graph_ret = &ret_entry->ret;
694 call = &entry->graph_ent;
695 duration = graph_ret->rettime - graph_ret->calltime;
696
697 if (data) {
698 struct fgraph_cpu_data *cpu_data;
699
700 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
701
702 /*
703 * Comments display at + 1 to depth. Since
704 * this is a leaf function, keep the comments
705 * equal to this depth.
706 */
707 cpu_data->depth = call->depth - 1;
708
709 /* No need to keep this function around for this depth */
710 if (call->depth < FTRACE_RETFUNC_DEPTH &&
711 !WARN_ON_ONCE(call->depth < 0))
712 cpu_data->enter_funcs[call->depth] = 0;
713 }
714
715 /* Overhead and duration */
716 print_graph_duration(tr, duration, s, flags);
717
718 /* Function */
719 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
720 trace_seq_putc(s, ' ');
721
722 /*
723 * Write out the function return value if the option function-retval is
724 * enabled.
725 */
726 if (flags & __TRACE_GRAPH_PRINT_RETVAL)
727 print_graph_retval(s, graph_ret->retval, true, (void *)call->func,
728 !!(flags & TRACE_GRAPH_PRINT_RETVAL_HEX));
729 else
730 trace_seq_printf(s, "%ps();\n", (void *)call->func);
731
732 print_graph_irq(iter, graph_ret->func, TRACE_GRAPH_RET,
733 cpu, iter->ent->pid, flags);
734
735 return trace_handle_return(s);
736}
737
738static enum print_line_t
739print_graph_entry_nested(struct trace_iterator *iter,
740 struct ftrace_graph_ent_entry *entry,
741 struct trace_seq *s, int cpu, u32 flags)
742{
743 struct ftrace_graph_ent *call = &entry->graph_ent;
744 struct fgraph_data *data = iter->private;
745 struct trace_array *tr = iter->tr;
746 int i;
747
748 if (data) {
749 struct fgraph_cpu_data *cpu_data;
750 int cpu = iter->cpu;
751
752 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
753 cpu_data->depth = call->depth;
754
755 /* Save this function pointer to see if the exit matches */
756 if (call->depth < FTRACE_RETFUNC_DEPTH &&
757 !WARN_ON_ONCE(call->depth < 0))
758 cpu_data->enter_funcs[call->depth] = call->func;
759 }
760
761 /* No time */
762 print_graph_duration(tr, 0, s, flags | FLAGS_FILL_FULL);
763
764 /* Function */
765 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
766 trace_seq_putc(s, ' ');
767
768 trace_seq_printf(s, "%ps() {\n", (void *)call->func);
769
770 if (trace_seq_has_overflowed(s))
771 return TRACE_TYPE_PARTIAL_LINE;
772
773 /*
774 * we already consumed the current entry to check the next one
775 * and see if this is a leaf.
776 */
777 return TRACE_TYPE_NO_CONSUME;
778}
779
780static void
781print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
782 int type, unsigned long addr, u32 flags)
783{
784 struct fgraph_data *data = iter->private;
785 struct trace_entry *ent = iter->ent;
786 struct trace_array *tr = iter->tr;
787 int cpu = iter->cpu;
788
789 /* Pid */
790 verif_pid(s, ent->pid, cpu, data);
791
792 if (type)
793 /* Interrupt */
794 print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
795
796 if (!(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
797 return;
798
799 /* Absolute time */
800 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
801 print_graph_abs_time(iter->ts, s);
802
803 /* Relative time */
804 if (flags & TRACE_GRAPH_PRINT_REL_TIME)
805 print_graph_rel_time(iter, s);
806
807 /* Cpu */
808 if (flags & TRACE_GRAPH_PRINT_CPU)
809 print_graph_cpu(s, cpu);
810
811 /* Proc */
812 if (flags & TRACE_GRAPH_PRINT_PROC) {
813 print_graph_proc(s, ent->pid);
814 trace_seq_puts(s, " | ");
815 }
816
817 /* Latency format */
818 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
819 print_graph_lat_fmt(s, ent);
820
821 return;
822}
823
824/*
825 * Entry check for irq code
826 *
827 * returns 1 if
828 * - we are inside irq code
829 * - we just entered irq code
830 *
831 * returns 0 if
832 * - funcgraph-interrupts option is set
833 * - we are not inside irq code
834 */
835static int
836check_irq_entry(struct trace_iterator *iter, u32 flags,
837 unsigned long addr, int depth)
838{
839 int cpu = iter->cpu;
840 int *depth_irq;
841 struct fgraph_data *data = iter->private;
842
843 /*
844 * If we are either displaying irqs, or we got called as
845 * a graph event and private data does not exist,
846 * then we bypass the irq check.
847 */
848 if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
849 (!data))
850 return 0;
851
852 depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
853
854 /*
855 * We are inside the irq code
856 */
857 if (*depth_irq >= 0)
858 return 1;
859
860 if ((addr < (unsigned long)__irqentry_text_start) ||
861 (addr >= (unsigned long)__irqentry_text_end))
862 return 0;
863
864 /*
865 * We are entering irq code.
866 */
867 *depth_irq = depth;
868 return 1;
869}
870
871/*
872 * Return check for irq code
873 *
874 * returns 1 if
875 * - we are inside irq code
876 * - we just left irq code
877 *
878 * returns 0 if
879 * - funcgraph-interrupts option is set
880 * - we are not inside irq code
881 */
882static int
883check_irq_return(struct trace_iterator *iter, u32 flags, int depth)
884{
885 int cpu = iter->cpu;
886 int *depth_irq;
887 struct fgraph_data *data = iter->private;
888
889 /*
890 * If we are either displaying irqs, or we got called as
891 * a graph event and private data does not exist,
892 * then we bypass the irq check.
893 */
894 if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
895 (!data))
896 return 0;
897
898 depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
899
900 /*
901 * We are not inside the irq code.
902 */
903 if (*depth_irq == -1)
904 return 0;
905
906 /*
907 * We are inside the irq code, and this is returning entry.
908 * Let's not trace it and clear the entry depth, since
909 * we are out of irq code.
910 *
911 * This condition ensures that we 'leave the irq code' once
912 * we are out of the entry depth. Thus protecting us from
913 * the RETURN entry loss.
914 */
915 if (*depth_irq >= depth) {
916 *depth_irq = -1;
917 return 1;
918 }
919
920 /*
921 * We are inside the irq code, and this is not the entry.
922 */
923 return 1;
924}
925
926static enum print_line_t
927print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
928 struct trace_iterator *iter, u32 flags)
929{
930 struct fgraph_data *data = iter->private;
931 struct ftrace_graph_ent *call = &field->graph_ent;
932 struct ftrace_graph_ret_entry *leaf_ret;
933 static enum print_line_t ret;
934 int cpu = iter->cpu;
935
936 if (check_irq_entry(iter, flags, call->func, call->depth))
937 return TRACE_TYPE_HANDLED;
938
939 print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags);
940
941 leaf_ret = get_return_for_leaf(iter, field);
942 if (leaf_ret)
943 ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags);
944 else
945 ret = print_graph_entry_nested(iter, field, s, cpu, flags);
946
947 if (data) {
948 /*
949 * If we failed to write our output, then we need to make
950 * note of it. Because we already consumed our entry.
951 */
952 if (s->full) {
953 data->failed = 1;
954 data->cpu = cpu;
955 } else
956 data->failed = 0;
957 }
958
959 return ret;
960}
961
962static enum print_line_t
963print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
964 struct trace_entry *ent, struct trace_iterator *iter,
965 u32 flags)
966{
967 unsigned long long duration = trace->rettime - trace->calltime;
968 struct fgraph_data *data = iter->private;
969 struct trace_array *tr = iter->tr;
970 pid_t pid = ent->pid;
971 int cpu = iter->cpu;
972 int func_match = 1;
973 int i;
974
975 if (check_irq_return(iter, flags, trace->depth))
976 return TRACE_TYPE_HANDLED;
977
978 if (data) {
979 struct fgraph_cpu_data *cpu_data;
980 int cpu = iter->cpu;
981
982 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
983
984 /*
985 * Comments display at + 1 to depth. This is the
986 * return from a function, we now want the comments
987 * to display at the same level of the bracket.
988 */
989 cpu_data->depth = trace->depth - 1;
990
991 if (trace->depth < FTRACE_RETFUNC_DEPTH &&
992 !WARN_ON_ONCE(trace->depth < 0)) {
993 if (cpu_data->enter_funcs[trace->depth] != trace->func)
994 func_match = 0;
995 cpu_data->enter_funcs[trace->depth] = 0;
996 }
997 }
998
999 print_graph_prologue(iter, s, 0, 0, flags);
1000
1001 /* Overhead and duration */
1002 print_graph_duration(tr, duration, s, flags);
1003
1004 /* Closing brace */
1005 for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++)
1006 trace_seq_putc(s, ' ');
1007
1008 /*
1009 * Always write out the function name and its return value if the
1010 * function-retval option is enabled.
1011 */
1012 if (flags & __TRACE_GRAPH_PRINT_RETVAL) {
1013 print_graph_retval(s, trace->retval, false, (void *)trace->func,
1014 !!(flags & TRACE_GRAPH_PRINT_RETVAL_HEX));
1015 } else {
1016 /*
1017 * If the return function does not have a matching entry,
1018 * then the entry was lost. Instead of just printing
1019 * the '}' and letting the user guess what function this
1020 * belongs to, write out the function name. Always do
1021 * that if the funcgraph-tail option is enabled.
1022 */
1023 if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL))
1024 trace_seq_puts(s, "}\n");
1025 else
1026 trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
1027 }
1028
1029 /* Overrun */
1030 if (flags & TRACE_GRAPH_PRINT_OVERRUN)
1031 trace_seq_printf(s, " (Overruns: %u)\n",
1032 trace->overrun);
1033
1034 print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
1035 cpu, pid, flags);
1036
1037 return trace_handle_return(s);
1038}
1039
1040static enum print_line_t
1041print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
1042 struct trace_iterator *iter, u32 flags)
1043{
1044 struct trace_array *tr = iter->tr;
1045 unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
1046 struct fgraph_data *data = iter->private;
1047 struct trace_event *event;
1048 int depth = 0;
1049 int ret;
1050 int i;
1051
1052 if (data)
1053 depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
1054
1055 print_graph_prologue(iter, s, 0, 0, flags);
1056
1057 /* No time */
1058 print_graph_duration(tr, 0, s, flags | FLAGS_FILL_FULL);
1059
1060 /* Indentation */
1061 if (depth > 0)
1062 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++)
1063 trace_seq_putc(s, ' ');
1064
1065 /* The comment */
1066 trace_seq_puts(s, "/* ");
1067
1068 switch (iter->ent->type) {
1069 case TRACE_BPUTS:
1070 ret = trace_print_bputs_msg_only(iter);
1071 if (ret != TRACE_TYPE_HANDLED)
1072 return ret;
1073 break;
1074 case TRACE_BPRINT:
1075 ret = trace_print_bprintk_msg_only(iter);
1076 if (ret != TRACE_TYPE_HANDLED)
1077 return ret;
1078 break;
1079 case TRACE_PRINT:
1080 ret = trace_print_printk_msg_only(iter);
1081 if (ret != TRACE_TYPE_HANDLED)
1082 return ret;
1083 break;
1084 default:
1085 event = ftrace_find_event(ent->type);
1086 if (!event)
1087 return TRACE_TYPE_UNHANDLED;
1088
1089 ret = event->funcs->trace(iter, sym_flags, event);
1090 if (ret != TRACE_TYPE_HANDLED)
1091 return ret;
1092 }
1093
1094 if (trace_seq_has_overflowed(s))
1095 goto out;
1096
1097 /* Strip ending newline */
1098 if (s->buffer[s->seq.len - 1] == '\n') {
1099 s->buffer[s->seq.len - 1] = '\0';
1100 s->seq.len--;
1101 }
1102
1103 trace_seq_puts(s, " */\n");
1104 out:
1105 return trace_handle_return(s);
1106}
1107
1108
1109enum print_line_t
1110print_graph_function_flags(struct trace_iterator *iter, u32 flags)
1111{
1112 struct ftrace_graph_ent_entry *field;
1113 struct fgraph_data *data = iter->private;
1114 struct trace_entry *entry = iter->ent;
1115 struct trace_seq *s = &iter->seq;
1116 int cpu = iter->cpu;
1117 int ret;
1118
1119 if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
1120 per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
1121 return TRACE_TYPE_HANDLED;
1122 }
1123
1124 /*
1125 * If the last output failed, there's a possibility we need
1126 * to print out the missing entry which would never go out.
1127 */
1128 if (data && data->failed) {
1129 field = &data->ent;
1130 iter->cpu = data->cpu;
1131 ret = print_graph_entry(field, s, iter, flags);
1132 if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
1133 per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
1134 ret = TRACE_TYPE_NO_CONSUME;
1135 }
1136 iter->cpu = cpu;
1137 return ret;
1138 }
1139
1140 switch (entry->type) {
1141 case TRACE_GRAPH_ENT: {
1142 /*
1143 * print_graph_entry() may consume the current event,
1144 * thus @field may become invalid, so we need to save it.
1145 * sizeof(struct ftrace_graph_ent_entry) is very small,
1146 * it can be safely saved at the stack.
1147 */
1148 struct ftrace_graph_ent_entry saved;
1149 trace_assign_type(field, entry);
1150 saved = *field;
1151 return print_graph_entry(&saved, s, iter, flags);
1152 }
1153 case TRACE_GRAPH_RET: {
1154 struct ftrace_graph_ret_entry *field;
1155 trace_assign_type(field, entry);
1156 return print_graph_return(&field->ret, s, entry, iter, flags);
1157 }
1158 case TRACE_STACK:
1159 case TRACE_FN:
1160 /* dont trace stack and functions as comments */
1161 return TRACE_TYPE_UNHANDLED;
1162
1163 default:
1164 return print_graph_comment(s, entry, iter, flags);
1165 }
1166
1167 return TRACE_TYPE_HANDLED;
1168}
1169
1170static enum print_line_t
1171print_graph_function(struct trace_iterator *iter)
1172{
1173 return print_graph_function_flags(iter, tracer_flags.val);
1174}
1175
1176static enum print_line_t
1177print_graph_function_event(struct trace_iterator *iter, int flags,
1178 struct trace_event *event)
1179{
1180 return print_graph_function(iter);
1181}
1182
1183static void print_lat_header(struct seq_file *s, u32 flags)
1184{
1185 static const char spaces[] = " " /* 16 spaces */
1186 " " /* 4 spaces */
1187 " "; /* 17 spaces */
1188 int size = 0;
1189
1190 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1191 size += 16;
1192 if (flags & TRACE_GRAPH_PRINT_REL_TIME)
1193 size += 16;
1194 if (flags & TRACE_GRAPH_PRINT_CPU)
1195 size += 4;
1196 if (flags & TRACE_GRAPH_PRINT_PROC)
1197 size += 17;
1198
1199 seq_printf(s, "#%.*s _-----=> irqs-off \n", size, spaces);
1200 seq_printf(s, "#%.*s / _----=> need-resched \n", size, spaces);
1201 seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
1202 seq_printf(s, "#%.*s|| / _--=> preempt-depth \n", size, spaces);
1203 seq_printf(s, "#%.*s||| / \n", size, spaces);
1204}
1205
1206static void __print_graph_headers_flags(struct trace_array *tr,
1207 struct seq_file *s, u32 flags)
1208{
1209 int lat = tr->trace_flags & TRACE_ITER_LATENCY_FMT;
1210
1211 if (lat)
1212 print_lat_header(s, flags);
1213
1214 /* 1st line */
1215 seq_putc(s, '#');
1216 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1217 seq_puts(s, " TIME ");
1218 if (flags & TRACE_GRAPH_PRINT_REL_TIME)
1219 seq_puts(s, " REL TIME ");
1220 if (flags & TRACE_GRAPH_PRINT_CPU)
1221 seq_puts(s, " CPU");
1222 if (flags & TRACE_GRAPH_PRINT_PROC)
1223 seq_puts(s, " TASK/PID ");
1224 if (lat)
1225 seq_puts(s, "|||| ");
1226 if (flags & TRACE_GRAPH_PRINT_DURATION)
1227 seq_puts(s, " DURATION ");
1228 seq_puts(s, " FUNCTION CALLS\n");
1229
1230 /* 2nd line */
1231 seq_putc(s, '#');
1232 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1233 seq_puts(s, " | ");
1234 if (flags & TRACE_GRAPH_PRINT_REL_TIME)
1235 seq_puts(s, " | ");
1236 if (flags & TRACE_GRAPH_PRINT_CPU)
1237 seq_puts(s, " | ");
1238 if (flags & TRACE_GRAPH_PRINT_PROC)
1239 seq_puts(s, " | | ");
1240 if (lat)
1241 seq_puts(s, "|||| ");
1242 if (flags & TRACE_GRAPH_PRINT_DURATION)
1243 seq_puts(s, " | | ");
1244 seq_puts(s, " | | | |\n");
1245}
1246
1247static void print_graph_headers(struct seq_file *s)
1248{
1249 print_graph_headers_flags(s, tracer_flags.val);
1250}
1251
1252void print_graph_headers_flags(struct seq_file *s, u32 flags)
1253{
1254 struct trace_iterator *iter = s->private;
1255 struct trace_array *tr = iter->tr;
1256
1257 if (!(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
1258 return;
1259
1260 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT) {
1261 /* print nothing if the buffers are empty */
1262 if (trace_empty(iter))
1263 return;
1264
1265 print_trace_header(s, iter);
1266 }
1267
1268 __print_graph_headers_flags(tr, s, flags);
1269}
1270
1271void graph_trace_open(struct trace_iterator *iter)
1272{
1273 /* pid and depth on the last trace processed */
1274 struct fgraph_data *data;
1275 gfp_t gfpflags;
1276 int cpu;
1277
1278 iter->private = NULL;
1279
1280 /* We can be called in atomic context via ftrace_dump() */
1281 gfpflags = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL;
1282
1283 data = kzalloc(sizeof(*data), gfpflags);
1284 if (!data)
1285 goto out_err;
1286
1287 data->cpu_data = alloc_percpu_gfp(struct fgraph_cpu_data, gfpflags);
1288 if (!data->cpu_data)
1289 goto out_err_free;
1290
1291 for_each_possible_cpu(cpu) {
1292 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
1293 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
1294 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
1295 int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1296
1297 *pid = -1;
1298 *depth = 0;
1299 *ignore = 0;
1300 *depth_irq = -1;
1301 }
1302
1303 iter->private = data;
1304
1305 return;
1306
1307 out_err_free:
1308 kfree(data);
1309 out_err:
1310 pr_warn("function graph tracer: not enough memory\n");
1311}
1312
1313void graph_trace_close(struct trace_iterator *iter)
1314{
1315 struct fgraph_data *data = iter->private;
1316
1317 if (data) {
1318 free_percpu(data->cpu_data);
1319 kfree(data);
1320 }
1321}
1322
1323static int
1324func_graph_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1325{
1326 if (bit == TRACE_GRAPH_PRINT_IRQS)
1327 ftrace_graph_skip_irqs = !set;
1328
1329 if (bit == TRACE_GRAPH_SLEEP_TIME)
1330 ftrace_graph_sleep_time_control(set);
1331
1332 if (bit == TRACE_GRAPH_GRAPH_TIME)
1333 ftrace_graph_graph_time_control(set);
1334
1335 return 0;
1336}
1337
1338static struct trace_event_functions graph_functions = {
1339 .trace = print_graph_function_event,
1340};
1341
1342static struct trace_event graph_trace_entry_event = {
1343 .type = TRACE_GRAPH_ENT,
1344 .funcs = &graph_functions,
1345};
1346
1347static struct trace_event graph_trace_ret_event = {
1348 .type = TRACE_GRAPH_RET,
1349 .funcs = &graph_functions
1350};
1351
1352static struct tracer graph_trace __tracer_data = {
1353 .name = "function_graph",
1354 .update_thresh = graph_trace_update_thresh,
1355 .open = graph_trace_open,
1356 .pipe_open = graph_trace_open,
1357 .close = graph_trace_close,
1358 .pipe_close = graph_trace_close,
1359 .init = graph_trace_init,
1360 .reset = graph_trace_reset,
1361 .print_line = print_graph_function,
1362 .print_header = print_graph_headers,
1363 .flags = &tracer_flags,
1364 .set_flag = func_graph_set_flag,
1365#ifdef CONFIG_FTRACE_SELFTEST
1366 .selftest = trace_selftest_startup_function_graph,
1367#endif
1368};
1369
1370
1371static ssize_t
1372graph_depth_write(struct file *filp, const char __user *ubuf, size_t cnt,
1373 loff_t *ppos)
1374{
1375 unsigned long val;
1376 int ret;
1377
1378 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1379 if (ret)
1380 return ret;
1381
1382 fgraph_max_depth = val;
1383
1384 *ppos += cnt;
1385
1386 return cnt;
1387}
1388
1389static ssize_t
1390graph_depth_read(struct file *filp, char __user *ubuf, size_t cnt,
1391 loff_t *ppos)
1392{
1393 char buf[15]; /* More than enough to hold UINT_MAX + "\n"*/
1394 int n;
1395
1396 n = sprintf(buf, "%d\n", fgraph_max_depth);
1397
1398 return simple_read_from_buffer(ubuf, cnt, ppos, buf, n);
1399}
1400
1401static const struct file_operations graph_depth_fops = {
1402 .open = tracing_open_generic,
1403 .write = graph_depth_write,
1404 .read = graph_depth_read,
1405 .llseek = generic_file_llseek,
1406};
1407
1408static __init int init_graph_tracefs(void)
1409{
1410 int ret;
1411
1412 ret = tracing_init_dentry();
1413 if (ret)
1414 return 0;
1415
1416 trace_create_file("max_graph_depth", TRACE_MODE_WRITE, NULL,
1417 NULL, &graph_depth_fops);
1418
1419 return 0;
1420}
1421fs_initcall(init_graph_tracefs);
1422
1423static __init int init_graph_trace(void)
1424{
1425 max_bytes_for_cpu = snprintf(NULL, 0, "%u", nr_cpu_ids - 1);
1426
1427 if (!register_trace_event(&graph_trace_entry_event)) {
1428 pr_warn("Warning: could not register graph trace events\n");
1429 return 1;
1430 }
1431
1432 if (!register_trace_event(&graph_trace_ret_event)) {
1433 pr_warn("Warning: could not register graph trace events\n");
1434 return 1;
1435 }
1436
1437 return register_tracer(&graph_trace);
1438}
1439
1440core_initcall(init_graph_trace);
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
19static bool kill_ftrace_graph;
20
21/**
22 * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called
23 *
24 * ftrace_graph_stop() is called when a severe error is detected in
25 * the function graph tracing. This function is called by the critical
26 * paths of function graph to keep those paths from doing any more harm.
27 */
28bool ftrace_graph_is_dead(void)
29{
30 return kill_ftrace_graph;
31}
32
33/**
34 * ftrace_graph_stop - set to permanently disable function graph tracincg
35 *
36 * In case of an error int function graph tracing, this is called
37 * to try to keep function graph tracing from causing any more harm.
38 * Usually this is pretty severe and this is called to try to at least
39 * get a warning out to the user.
40 */
41void ftrace_graph_stop(void)
42{
43 kill_ftrace_graph = true;
44}
45
46/* When set, irq functions will be ignored */
47static int ftrace_graph_skip_irqs;
48
49struct fgraph_cpu_data {
50 pid_t last_pid;
51 int depth;
52 int depth_irq;
53 int ignore;
54 unsigned long enter_funcs[FTRACE_RETFUNC_DEPTH];
55};
56
57struct fgraph_data {
58 struct fgraph_cpu_data __percpu *cpu_data;
59
60 /* Place to preserve last processed entry. */
61 struct ftrace_graph_ent_entry ent;
62 struct ftrace_graph_ret_entry ret;
63 int failed;
64 int cpu;
65};
66
67#define TRACE_GRAPH_INDENT 2
68
69unsigned int fgraph_max_depth;
70
71static struct tracer_opt trace_opts[] = {
72 /* Display overruns? (for self-debug purpose) */
73 { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
74 /* Display CPU ? */
75 { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
76 /* Display Overhead ? */
77 { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
78 /* Display proc name/pid */
79 { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
80 /* Display duration of execution */
81 { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
82 /* Display absolute time of an entry */
83 { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
84 /* Display interrupts */
85 { TRACER_OPT(funcgraph-irqs, TRACE_GRAPH_PRINT_IRQS) },
86 /* Display function name after trailing } */
87 { TRACER_OPT(funcgraph-tail, TRACE_GRAPH_PRINT_TAIL) },
88 /* Include sleep time (scheduled out) between entry and return */
89 { TRACER_OPT(sleep-time, TRACE_GRAPH_SLEEP_TIME) },
90 /* Include time within nested functions */
91 { TRACER_OPT(graph-time, TRACE_GRAPH_GRAPH_TIME) },
92 { } /* Empty entry */
93};
94
95static 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 TRACE_GRAPH_SLEEP_TIME | TRACE_GRAPH_GRAPH_TIME,
100 .opts = trace_opts
101};
102
103static struct trace_array *graph_array;
104
105/*
106 * DURATION column is being also used to display IRQ signs,
107 * following values are used by print_graph_irq and others
108 * to fill in space into DURATION column.
109 */
110enum {
111 FLAGS_FILL_FULL = 1 << TRACE_GRAPH_PRINT_FILL_SHIFT,
112 FLAGS_FILL_START = 2 << TRACE_GRAPH_PRINT_FILL_SHIFT,
113 FLAGS_FILL_END = 3 << TRACE_GRAPH_PRINT_FILL_SHIFT,
114};
115
116static void
117print_graph_duration(struct trace_array *tr, unsigned long long duration,
118 struct trace_seq *s, u32 flags);
119
120/* Add a function return address to the trace stack on thread info.*/
121int
122ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
123 unsigned long frame_pointer, unsigned long *retp)
124{
125 unsigned long long calltime;
126 int index;
127
128 if (unlikely(ftrace_graph_is_dead()))
129 return -EBUSY;
130
131 if (!current->ret_stack)
132 return -EBUSY;
133
134 /*
135 * We must make sure the ret_stack is tested before we read
136 * anything else.
137 */
138 smp_rmb();
139
140 /* The return trace stack is full */
141 if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
142 atomic_inc(¤t->trace_overrun);
143 return -EBUSY;
144 }
145
146 /*
147 * The curr_ret_stack is an index to ftrace return stack of
148 * current task. Its value should be in [0, FTRACE_RETFUNC_
149 * DEPTH) when the function graph tracer is used. To support
150 * filtering out specific functions, it makes the index
151 * negative by subtracting huge value (FTRACE_NOTRACE_DEPTH)
152 * so when it sees a negative index the ftrace will ignore
153 * the record. And the index gets recovered when returning
154 * from the filtered function by adding the FTRACE_NOTRACE_
155 * DEPTH and then it'll continue to record functions normally.
156 *
157 * The curr_ret_stack is initialized to -1 and get increased
158 * in this function. So it can be less than -1 only if it was
159 * filtered out via ftrace_graph_notrace_addr() which can be
160 * set from set_graph_notrace file in tracefs by user.
161 */
162 if (current->curr_ret_stack < -1)
163 return -EBUSY;
164
165 calltime = trace_clock_local();
166
167 index = ++current->curr_ret_stack;
168 if (ftrace_graph_notrace_addr(func))
169 current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH;
170 barrier();
171 current->ret_stack[index].ret = ret;
172 current->ret_stack[index].func = func;
173 current->ret_stack[index].calltime = calltime;
174#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
175 current->ret_stack[index].fp = frame_pointer;
176#endif
177#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
178 current->ret_stack[index].retp = retp;
179#endif
180 *depth = current->curr_ret_stack;
181
182 return 0;
183}
184
185/* Retrieve a function return address to the trace stack on thread info.*/
186static void
187ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
188 unsigned long frame_pointer)
189{
190 int index;
191
192 index = current->curr_ret_stack;
193
194 /*
195 * A negative index here means that it's just returned from a
196 * notrace'd function. Recover index to get an original
197 * return address. See ftrace_push_return_trace().
198 *
199 * TODO: Need to check whether the stack gets corrupted.
200 */
201 if (index < 0)
202 index += FTRACE_NOTRACE_DEPTH;
203
204 if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) {
205 ftrace_graph_stop();
206 WARN_ON(1);
207 /* Might as well panic, otherwise we have no where to go */
208 *ret = (unsigned long)panic;
209 return;
210 }
211
212#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
213 /*
214 * The arch may choose to record the frame pointer used
215 * and check it here to make sure that it is what we expect it
216 * to be. If gcc does not set the place holder of the return
217 * address in the frame pointer, and does a copy instead, then
218 * the function graph trace will fail. This test detects this
219 * case.
220 *
221 * Currently, x86_32 with optimize for size (-Os) makes the latest
222 * gcc do the above.
223 *
224 * Note, -mfentry does not use frame pointers, and this test
225 * is not needed if CC_USING_FENTRY is set.
226 */
227 if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
228 ftrace_graph_stop();
229 WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
230 " from func %ps return to %lx\n",
231 current->ret_stack[index].fp,
232 frame_pointer,
233 (void *)current->ret_stack[index].func,
234 current->ret_stack[index].ret);
235 *ret = (unsigned long)panic;
236 return;
237 }
238#endif
239
240 *ret = current->ret_stack[index].ret;
241 trace->func = current->ret_stack[index].func;
242 trace->calltime = current->ret_stack[index].calltime;
243 trace->overrun = atomic_read(¤t->trace_overrun);
244 trace->depth = index;
245}
246
247/*
248 * Send the trace to the ring-buffer.
249 * @return the original return address.
250 */
251unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
252{
253 struct ftrace_graph_ret trace;
254 unsigned long ret;
255
256 ftrace_pop_return_trace(&trace, &ret, frame_pointer);
257 trace.rettime = trace_clock_local();
258 barrier();
259 current->curr_ret_stack--;
260 /*
261 * The curr_ret_stack can be less than -1 only if it was
262 * filtered out and it's about to return from the function.
263 * Recover the index and continue to trace normal functions.
264 */
265 if (current->curr_ret_stack < -1) {
266 current->curr_ret_stack += FTRACE_NOTRACE_DEPTH;
267 return ret;
268 }
269
270 /*
271 * The trace should run after decrementing the ret counter
272 * in case an interrupt were to come in. We don't want to
273 * lose the interrupt if max_depth is set.
274 */
275 ftrace_graph_return(&trace);
276
277 if (unlikely(!ret)) {
278 ftrace_graph_stop();
279 WARN_ON(1);
280 /* Might as well panic. What else to do? */
281 ret = (unsigned long)panic;
282 }
283
284 return ret;
285}
286
287/**
288 * ftrace_graph_ret_addr - convert a potentially modified stack return address
289 * to its original value
290 *
291 * This function can be called by stack unwinding code to convert a found stack
292 * return address ('ret') to its original value, in case the function graph
293 * tracer has modified it to be 'return_to_handler'. If the address hasn't
294 * been modified, the unchanged value of 'ret' is returned.
295 *
296 * 'idx' is a state variable which should be initialized by the caller to zero
297 * before the first call.
298 *
299 * 'retp' is a pointer to the return address on the stack. It's ignored if
300 * the arch doesn't have HAVE_FUNCTION_GRAPH_RET_ADDR_PTR defined.
301 */
302#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
303unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
304 unsigned long ret, unsigned long *retp)
305{
306 int index = task->curr_ret_stack;
307 int i;
308
309 if (ret != (unsigned long)return_to_handler)
310 return ret;
311
312 if (index < -1)
313 index += FTRACE_NOTRACE_DEPTH;
314
315 if (index < 0)
316 return ret;
317
318 for (i = 0; i <= index; i++)
319 if (task->ret_stack[i].retp == retp)
320 return task->ret_stack[i].ret;
321
322 return ret;
323}
324#else /* !HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */
325unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
326 unsigned long ret, unsigned long *retp)
327{
328 int task_idx;
329
330 if (ret != (unsigned long)return_to_handler)
331 return ret;
332
333 task_idx = task->curr_ret_stack;
334
335 if (!task->ret_stack || task_idx < *idx)
336 return ret;
337
338 task_idx -= *idx;
339 (*idx)++;
340
341 return task->ret_stack[task_idx].ret;
342}
343#endif /* HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */
344
345int __trace_graph_entry(struct trace_array *tr,
346 struct ftrace_graph_ent *trace,
347 unsigned long flags,
348 int pc)
349{
350 struct trace_event_call *call = &event_funcgraph_entry;
351 struct ring_buffer_event *event;
352 struct ring_buffer *buffer = tr->trace_buffer.buffer;
353 struct ftrace_graph_ent_entry *entry;
354
355 event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
356 sizeof(*entry), flags, pc);
357 if (!event)
358 return 0;
359 entry = ring_buffer_event_data(event);
360 entry->graph_ent = *trace;
361 if (!call_filter_check_discard(call, entry, buffer, event))
362 trace_buffer_unlock_commit_nostack(buffer, event);
363
364 return 1;
365}
366
367static inline int ftrace_graph_ignore_irqs(void)
368{
369 if (!ftrace_graph_skip_irqs || trace_recursion_test(TRACE_IRQ_BIT))
370 return 0;
371
372 return in_irq();
373}
374
375int trace_graph_entry(struct ftrace_graph_ent *trace)
376{
377 struct trace_array *tr = graph_array;
378 struct trace_array_cpu *data;
379 unsigned long flags;
380 long disabled;
381 int ret;
382 int cpu;
383 int pc;
384
385 if (!ftrace_trace_task(tr))
386 return 0;
387
388 if (ftrace_graph_ignore_func(trace))
389 return 0;
390
391 if (ftrace_graph_ignore_irqs())
392 return 0;
393
394 /*
395 * Do not trace a function if it's filtered by set_graph_notrace.
396 * Make the index of ret stack negative to indicate that it should
397 * ignore further functions. But it needs its own ret stack entry
398 * to recover the original index in order to continue tracing after
399 * returning from the function.
400 */
401 if (ftrace_graph_notrace_addr(trace->func))
402 return 1;
403
404 /*
405 * Stop here if tracing_threshold is set. We only write function return
406 * events to the ring buffer.
407 */
408 if (tracing_thresh)
409 return 1;
410
411 local_irq_save(flags);
412 cpu = raw_smp_processor_id();
413 data = per_cpu_ptr(tr->trace_buffer.data, cpu);
414 disabled = atomic_inc_return(&data->disabled);
415 if (likely(disabled == 1)) {
416 pc = preempt_count();
417 ret = __trace_graph_entry(tr, trace, flags, pc);
418 } else {
419 ret = 0;
420 }
421
422 atomic_dec(&data->disabled);
423 local_irq_restore(flags);
424
425 return ret;
426}
427
428static void
429__trace_graph_function(struct trace_array *tr,
430 unsigned long ip, unsigned long flags, int pc)
431{
432 u64 time = trace_clock_local();
433 struct ftrace_graph_ent ent = {
434 .func = ip,
435 .depth = 0,
436 };
437 struct ftrace_graph_ret ret = {
438 .func = ip,
439 .depth = 0,
440 .calltime = time,
441 .rettime = time,
442 };
443
444 __trace_graph_entry(tr, &ent, flags, pc);
445 __trace_graph_return(tr, &ret, flags, pc);
446}
447
448void
449trace_graph_function(struct trace_array *tr,
450 unsigned long ip, unsigned long parent_ip,
451 unsigned long flags, int pc)
452{
453 __trace_graph_function(tr, ip, flags, pc);
454}
455
456void __trace_graph_return(struct trace_array *tr,
457 struct ftrace_graph_ret *trace,
458 unsigned long flags,
459 int pc)
460{
461 struct trace_event_call *call = &event_funcgraph_exit;
462 struct ring_buffer_event *event;
463 struct ring_buffer *buffer = tr->trace_buffer.buffer;
464 struct ftrace_graph_ret_entry *entry;
465
466 event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
467 sizeof(*entry), flags, pc);
468 if (!event)
469 return;
470 entry = ring_buffer_event_data(event);
471 entry->ret = *trace;
472 if (!call_filter_check_discard(call, entry, buffer, event))
473 trace_buffer_unlock_commit_nostack(buffer, event);
474}
475
476void trace_graph_return(struct ftrace_graph_ret *trace)
477{
478 struct trace_array *tr = graph_array;
479 struct trace_array_cpu *data;
480 unsigned long flags;
481 long disabled;
482 int cpu;
483 int pc;
484
485 local_irq_save(flags);
486 cpu = raw_smp_processor_id();
487 data = per_cpu_ptr(tr->trace_buffer.data, cpu);
488 disabled = atomic_inc_return(&data->disabled);
489 if (likely(disabled == 1)) {
490 pc = preempt_count();
491 __trace_graph_return(tr, trace, flags, pc);
492 }
493 atomic_dec(&data->disabled);
494 local_irq_restore(flags);
495}
496
497void set_graph_array(struct trace_array *tr)
498{
499 graph_array = tr;
500
501 /* Make graph_array visible before we start tracing */
502
503 smp_mb();
504}
505
506static void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
507{
508 if (tracing_thresh &&
509 (trace->rettime - trace->calltime < tracing_thresh))
510 return;
511 else
512 trace_graph_return(trace);
513}
514
515static int graph_trace_init(struct trace_array *tr)
516{
517 int ret;
518
519 set_graph_array(tr);
520 if (tracing_thresh)
521 ret = register_ftrace_graph(&trace_graph_thresh_return,
522 &trace_graph_entry);
523 else
524 ret = register_ftrace_graph(&trace_graph_return,
525 &trace_graph_entry);
526 if (ret)
527 return ret;
528 tracing_start_cmdline_record();
529
530 return 0;
531}
532
533static void graph_trace_reset(struct trace_array *tr)
534{
535 tracing_stop_cmdline_record();
536 unregister_ftrace_graph();
537}
538
539static int graph_trace_update_thresh(struct trace_array *tr)
540{
541 graph_trace_reset(tr);
542 return graph_trace_init(tr);
543}
544
545static int max_bytes_for_cpu;
546
547static void print_graph_cpu(struct trace_seq *s, int cpu)
548{
549 /*
550 * Start with a space character - to make it stand out
551 * to the right a bit when trace output is pasted into
552 * email:
553 */
554 trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
555}
556
557#define TRACE_GRAPH_PROCINFO_LENGTH 14
558
559static void print_graph_proc(struct trace_seq *s, pid_t pid)
560{
561 char comm[TASK_COMM_LEN];
562 /* sign + log10(MAX_INT) + '\0' */
563 char pid_str[11];
564 int spaces = 0;
565 int len;
566 int i;
567
568 trace_find_cmdline(pid, comm);
569 comm[7] = '\0';
570 sprintf(pid_str, "%d", pid);
571
572 /* 1 stands for the "-" character */
573 len = strlen(comm) + strlen(pid_str) + 1;
574
575 if (len < TRACE_GRAPH_PROCINFO_LENGTH)
576 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
577
578 /* First spaces to align center */
579 for (i = 0; i < spaces / 2; i++)
580 trace_seq_putc(s, ' ');
581
582 trace_seq_printf(s, "%s-%s", comm, pid_str);
583
584 /* Last spaces to align center */
585 for (i = 0; i < spaces - (spaces / 2); i++)
586 trace_seq_putc(s, ' ');
587}
588
589
590static void print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
591{
592 trace_seq_putc(s, ' ');
593 trace_print_lat_fmt(s, entry);
594}
595
596/* If the pid changed since the last trace, output this event */
597static void
598verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
599{
600 pid_t prev_pid;
601 pid_t *last_pid;
602
603 if (!data)
604 return;
605
606 last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
607
608 if (*last_pid == pid)
609 return;
610
611 prev_pid = *last_pid;
612 *last_pid = pid;
613
614 if (prev_pid == -1)
615 return;
616/*
617 * Context-switch trace line:
618
619 ------------------------------------------
620 | 1) migration/0--1 => sshd-1755
621 ------------------------------------------
622
623 */
624 trace_seq_puts(s, " ------------------------------------------\n");
625 print_graph_cpu(s, cpu);
626 print_graph_proc(s, prev_pid);
627 trace_seq_puts(s, " => ");
628 print_graph_proc(s, pid);
629 trace_seq_puts(s, "\n ------------------------------------------\n\n");
630}
631
632static struct ftrace_graph_ret_entry *
633get_return_for_leaf(struct trace_iterator *iter,
634 struct ftrace_graph_ent_entry *curr)
635{
636 struct fgraph_data *data = iter->private;
637 struct ring_buffer_iter *ring_iter = NULL;
638 struct ring_buffer_event *event;
639 struct ftrace_graph_ret_entry *next;
640
641 /*
642 * If the previous output failed to write to the seq buffer,
643 * then we just reuse the data from before.
644 */
645 if (data && data->failed) {
646 curr = &data->ent;
647 next = &data->ret;
648 } else {
649
650 ring_iter = trace_buffer_iter(iter, iter->cpu);
651
652 /* First peek to compare current entry and the next one */
653 if (ring_iter)
654 event = ring_buffer_iter_peek(ring_iter, NULL);
655 else {
656 /*
657 * We need to consume the current entry to see
658 * the next one.
659 */
660 ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu,
661 NULL, NULL);
662 event = ring_buffer_peek(iter->trace_buffer->buffer, iter->cpu,
663 NULL, NULL);
664 }
665
666 if (!event)
667 return NULL;
668
669 next = ring_buffer_event_data(event);
670
671 if (data) {
672 /*
673 * Save current and next entries for later reference
674 * if the output fails.
675 */
676 data->ent = *curr;
677 /*
678 * If the next event is not a return type, then
679 * we only care about what type it is. Otherwise we can
680 * safely copy the entire event.
681 */
682 if (next->ent.type == TRACE_GRAPH_RET)
683 data->ret = *next;
684 else
685 data->ret.ent.type = next->ent.type;
686 }
687 }
688
689 if (next->ent.type != TRACE_GRAPH_RET)
690 return NULL;
691
692 if (curr->ent.pid != next->ent.pid ||
693 curr->graph_ent.func != next->ret.func)
694 return NULL;
695
696 /* this is a leaf, now advance the iterator */
697 if (ring_iter)
698 ring_buffer_read(ring_iter, NULL);
699
700 return next;
701}
702
703static void print_graph_abs_time(u64 t, struct trace_seq *s)
704{
705 unsigned long usecs_rem;
706
707 usecs_rem = do_div(t, NSEC_PER_SEC);
708 usecs_rem /= 1000;
709
710 trace_seq_printf(s, "%5lu.%06lu | ",
711 (unsigned long)t, usecs_rem);
712}
713
714static void
715print_graph_irq(struct trace_iterator *iter, unsigned long addr,
716 enum trace_type type, int cpu, pid_t pid, u32 flags)
717{
718 struct trace_array *tr = iter->tr;
719 struct trace_seq *s = &iter->seq;
720 struct trace_entry *ent = iter->ent;
721
722 if (addr < (unsigned long)__irqentry_text_start ||
723 addr >= (unsigned long)__irqentry_text_end)
724 return;
725
726 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
727 /* Absolute time */
728 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
729 print_graph_abs_time(iter->ts, s);
730
731 /* Cpu */
732 if (flags & TRACE_GRAPH_PRINT_CPU)
733 print_graph_cpu(s, cpu);
734
735 /* Proc */
736 if (flags & TRACE_GRAPH_PRINT_PROC) {
737 print_graph_proc(s, pid);
738 trace_seq_puts(s, " | ");
739 }
740
741 /* Latency format */
742 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
743 print_graph_lat_fmt(s, ent);
744 }
745
746 /* No overhead */
747 print_graph_duration(tr, 0, s, flags | FLAGS_FILL_START);
748
749 if (type == TRACE_GRAPH_ENT)
750 trace_seq_puts(s, "==========>");
751 else
752 trace_seq_puts(s, "<==========");
753
754 print_graph_duration(tr, 0, s, flags | FLAGS_FILL_END);
755 trace_seq_putc(s, '\n');
756}
757
758void
759trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
760{
761 unsigned long nsecs_rem = do_div(duration, 1000);
762 /* log10(ULONG_MAX) + '\0' */
763 char usecs_str[21];
764 char nsecs_str[5];
765 int len;
766 int i;
767
768 sprintf(usecs_str, "%lu", (unsigned long) duration);
769
770 /* Print msecs */
771 trace_seq_printf(s, "%s", usecs_str);
772
773 len = strlen(usecs_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 trace_seq_printf(s, ".%s", nsecs_str);
781 len += strlen(nsecs_str) + 1;
782 }
783
784 trace_seq_puts(s, " us ");
785
786 /* Print remaining spaces to fit the row's width */
787 for (i = len; i < 8; i++)
788 trace_seq_putc(s, ' ');
789}
790
791static void
792print_graph_duration(struct trace_array *tr, unsigned long long duration,
793 struct trace_seq *s, u32 flags)
794{
795 if (!(flags & TRACE_GRAPH_PRINT_DURATION) ||
796 !(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
797 return;
798
799 /* No real adata, just filling the column with spaces */
800 switch (flags & TRACE_GRAPH_PRINT_FILL_MASK) {
801 case FLAGS_FILL_FULL:
802 trace_seq_puts(s, " | ");
803 return;
804 case FLAGS_FILL_START:
805 trace_seq_puts(s, " ");
806 return;
807 case FLAGS_FILL_END:
808 trace_seq_puts(s, " |");
809 return;
810 }
811
812 /* Signal a overhead of time execution to the output */
813 if (flags & TRACE_GRAPH_PRINT_OVERHEAD)
814 trace_seq_printf(s, "%c ", trace_find_mark(duration));
815 else
816 trace_seq_puts(s, " ");
817
818 trace_print_graph_duration(duration, s);
819 trace_seq_puts(s, "| ");
820}
821
822/* Case of a leaf function on its call entry */
823static enum print_line_t
824print_graph_entry_leaf(struct trace_iterator *iter,
825 struct ftrace_graph_ent_entry *entry,
826 struct ftrace_graph_ret_entry *ret_entry,
827 struct trace_seq *s, u32 flags)
828{
829 struct fgraph_data *data = iter->private;
830 struct trace_array *tr = iter->tr;
831 struct ftrace_graph_ret *graph_ret;
832 struct ftrace_graph_ent *call;
833 unsigned long long duration;
834 int i;
835
836 graph_ret = &ret_entry->ret;
837 call = &entry->graph_ent;
838 duration = graph_ret->rettime - graph_ret->calltime;
839
840 if (data) {
841 struct fgraph_cpu_data *cpu_data;
842 int cpu = iter->cpu;
843
844 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
845
846 /* If a graph tracer ignored set_graph_notrace */
847 if (call->depth < -1)
848 call->depth += FTRACE_NOTRACE_DEPTH;
849
850 /*
851 * Comments display at + 1 to depth. Since
852 * this is a leaf function, keep the comments
853 * equal to this depth.
854 */
855 cpu_data->depth = call->depth - 1;
856
857 /* No need to keep this function around for this depth */
858 if (call->depth < FTRACE_RETFUNC_DEPTH &&
859 !WARN_ON_ONCE(call->depth < 0))
860 cpu_data->enter_funcs[call->depth] = 0;
861 }
862
863 /* Overhead and duration */
864 print_graph_duration(tr, duration, s, flags);
865
866 /* Function */
867 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
868 trace_seq_putc(s, ' ');
869
870 trace_seq_printf(s, "%ps();\n", (void *)call->func);
871
872 return trace_handle_return(s);
873}
874
875static enum print_line_t
876print_graph_entry_nested(struct trace_iterator *iter,
877 struct ftrace_graph_ent_entry *entry,
878 struct trace_seq *s, int cpu, u32 flags)
879{
880 struct ftrace_graph_ent *call = &entry->graph_ent;
881 struct fgraph_data *data = iter->private;
882 struct trace_array *tr = iter->tr;
883 int i;
884
885 if (data) {
886 struct fgraph_cpu_data *cpu_data;
887 int cpu = iter->cpu;
888
889 /* If a graph tracer ignored set_graph_notrace */
890 if (call->depth < -1)
891 call->depth += FTRACE_NOTRACE_DEPTH;
892
893 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
894 cpu_data->depth = call->depth;
895
896 /* Save this function pointer to see if the exit matches */
897 if (call->depth < FTRACE_RETFUNC_DEPTH &&
898 !WARN_ON_ONCE(call->depth < 0))
899 cpu_data->enter_funcs[call->depth] = call->func;
900 }
901
902 /* No time */
903 print_graph_duration(tr, 0, s, flags | FLAGS_FILL_FULL);
904
905 /* Function */
906 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
907 trace_seq_putc(s, ' ');
908
909 trace_seq_printf(s, "%ps() {\n", (void *)call->func);
910
911 if (trace_seq_has_overflowed(s))
912 return TRACE_TYPE_PARTIAL_LINE;
913
914 /*
915 * we already consumed the current entry to check the next one
916 * and see if this is a leaf.
917 */
918 return TRACE_TYPE_NO_CONSUME;
919}
920
921static void
922print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
923 int type, unsigned long addr, u32 flags)
924{
925 struct fgraph_data *data = iter->private;
926 struct trace_entry *ent = iter->ent;
927 struct trace_array *tr = iter->tr;
928 int cpu = iter->cpu;
929
930 /* Pid */
931 verif_pid(s, ent->pid, cpu, data);
932
933 if (type)
934 /* Interrupt */
935 print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
936
937 if (!(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
938 return;
939
940 /* Absolute time */
941 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
942 print_graph_abs_time(iter->ts, s);
943
944 /* Cpu */
945 if (flags & TRACE_GRAPH_PRINT_CPU)
946 print_graph_cpu(s, cpu);
947
948 /* Proc */
949 if (flags & TRACE_GRAPH_PRINT_PROC) {
950 print_graph_proc(s, ent->pid);
951 trace_seq_puts(s, " | ");
952 }
953
954 /* Latency format */
955 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
956 print_graph_lat_fmt(s, ent);
957
958 return;
959}
960
961/*
962 * Entry check for irq code
963 *
964 * returns 1 if
965 * - we are inside irq code
966 * - we just entered irq code
967 *
968 * retunns 0 if
969 * - funcgraph-interrupts option is set
970 * - we are not inside irq code
971 */
972static int
973check_irq_entry(struct trace_iterator *iter, u32 flags,
974 unsigned long addr, int depth)
975{
976 int cpu = iter->cpu;
977 int *depth_irq;
978 struct fgraph_data *data = iter->private;
979
980 /*
981 * If we are either displaying irqs, or we got called as
982 * a graph event and private data does not exist,
983 * then we bypass the irq check.
984 */
985 if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
986 (!data))
987 return 0;
988
989 depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
990
991 /*
992 * We are inside the irq code
993 */
994 if (*depth_irq >= 0)
995 return 1;
996
997 if ((addr < (unsigned long)__irqentry_text_start) ||
998 (addr >= (unsigned long)__irqentry_text_end))
999 return 0;
1000
1001 /*
1002 * We are entering irq code.
1003 */
1004 *depth_irq = depth;
1005 return 1;
1006}
1007
1008/*
1009 * Return check for irq code
1010 *
1011 * returns 1 if
1012 * - we are inside irq code
1013 * - we just left irq code
1014 *
1015 * returns 0 if
1016 * - funcgraph-interrupts option is set
1017 * - we are not inside irq code
1018 */
1019static int
1020check_irq_return(struct trace_iterator *iter, u32 flags, int depth)
1021{
1022 int cpu = iter->cpu;
1023 int *depth_irq;
1024 struct fgraph_data *data = iter->private;
1025
1026 /*
1027 * If we are either displaying irqs, or we got called as
1028 * a graph event and private data does not exist,
1029 * then we bypass the irq check.
1030 */
1031 if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
1032 (!data))
1033 return 0;
1034
1035 depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1036
1037 /*
1038 * We are not inside the irq code.
1039 */
1040 if (*depth_irq == -1)
1041 return 0;
1042
1043 /*
1044 * We are inside the irq code, and this is returning entry.
1045 * Let's not trace it and clear the entry depth, since
1046 * we are out of irq code.
1047 *
1048 * This condition ensures that we 'leave the irq code' once
1049 * we are out of the entry depth. Thus protecting us from
1050 * the RETURN entry loss.
1051 */
1052 if (*depth_irq >= depth) {
1053 *depth_irq = -1;
1054 return 1;
1055 }
1056
1057 /*
1058 * We are inside the irq code, and this is not the entry.
1059 */
1060 return 1;
1061}
1062
1063static enum print_line_t
1064print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
1065 struct trace_iterator *iter, u32 flags)
1066{
1067 struct fgraph_data *data = iter->private;
1068 struct ftrace_graph_ent *call = &field->graph_ent;
1069 struct ftrace_graph_ret_entry *leaf_ret;
1070 static enum print_line_t ret;
1071 int cpu = iter->cpu;
1072
1073 if (check_irq_entry(iter, flags, call->func, call->depth))
1074 return TRACE_TYPE_HANDLED;
1075
1076 print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags);
1077
1078 leaf_ret = get_return_for_leaf(iter, field);
1079 if (leaf_ret)
1080 ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags);
1081 else
1082 ret = print_graph_entry_nested(iter, field, s, cpu, flags);
1083
1084 if (data) {
1085 /*
1086 * If we failed to write our output, then we need to make
1087 * note of it. Because we already consumed our entry.
1088 */
1089 if (s->full) {
1090 data->failed = 1;
1091 data->cpu = cpu;
1092 } else
1093 data->failed = 0;
1094 }
1095
1096 return ret;
1097}
1098
1099static enum print_line_t
1100print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
1101 struct trace_entry *ent, struct trace_iterator *iter,
1102 u32 flags)
1103{
1104 unsigned long long duration = trace->rettime - trace->calltime;
1105 struct fgraph_data *data = iter->private;
1106 struct trace_array *tr = iter->tr;
1107 pid_t pid = ent->pid;
1108 int cpu = iter->cpu;
1109 int func_match = 1;
1110 int i;
1111
1112 if (check_irq_return(iter, flags, trace->depth))
1113 return TRACE_TYPE_HANDLED;
1114
1115 if (data) {
1116 struct fgraph_cpu_data *cpu_data;
1117 int cpu = iter->cpu;
1118
1119 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
1120
1121 /*
1122 * Comments display at + 1 to depth. This is the
1123 * return from a function, we now want the comments
1124 * to display at the same level of the bracket.
1125 */
1126 cpu_data->depth = trace->depth - 1;
1127
1128 if (trace->depth < FTRACE_RETFUNC_DEPTH &&
1129 !WARN_ON_ONCE(trace->depth < 0)) {
1130 if (cpu_data->enter_funcs[trace->depth] != trace->func)
1131 func_match = 0;
1132 cpu_data->enter_funcs[trace->depth] = 0;
1133 }
1134 }
1135
1136 print_graph_prologue(iter, s, 0, 0, flags);
1137
1138 /* Overhead and duration */
1139 print_graph_duration(tr, duration, s, flags);
1140
1141 /* Closing brace */
1142 for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++)
1143 trace_seq_putc(s, ' ');
1144
1145 /*
1146 * If the return function does not have a matching entry,
1147 * then the entry was lost. Instead of just printing
1148 * the '}' and letting the user guess what function this
1149 * belongs to, write out the function name. Always do
1150 * that if the funcgraph-tail option is enabled.
1151 */
1152 if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL))
1153 trace_seq_puts(s, "}\n");
1154 else
1155 trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
1156
1157 /* Overrun */
1158 if (flags & TRACE_GRAPH_PRINT_OVERRUN)
1159 trace_seq_printf(s, " (Overruns: %lu)\n",
1160 trace->overrun);
1161
1162 print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
1163 cpu, pid, flags);
1164
1165 return trace_handle_return(s);
1166}
1167
1168static enum print_line_t
1169print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
1170 struct trace_iterator *iter, u32 flags)
1171{
1172 struct trace_array *tr = iter->tr;
1173 unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
1174 struct fgraph_data *data = iter->private;
1175 struct trace_event *event;
1176 int depth = 0;
1177 int ret;
1178 int i;
1179
1180 if (data)
1181 depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
1182
1183 print_graph_prologue(iter, s, 0, 0, flags);
1184
1185 /* No time */
1186 print_graph_duration(tr, 0, s, flags | FLAGS_FILL_FULL);
1187
1188 /* Indentation */
1189 if (depth > 0)
1190 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++)
1191 trace_seq_putc(s, ' ');
1192
1193 /* The comment */
1194 trace_seq_puts(s, "/* ");
1195
1196 switch (iter->ent->type) {
1197 case TRACE_BPUTS:
1198 ret = trace_print_bputs_msg_only(iter);
1199 if (ret != TRACE_TYPE_HANDLED)
1200 return ret;
1201 break;
1202 case TRACE_BPRINT:
1203 ret = trace_print_bprintk_msg_only(iter);
1204 if (ret != TRACE_TYPE_HANDLED)
1205 return ret;
1206 break;
1207 case TRACE_PRINT:
1208 ret = trace_print_printk_msg_only(iter);
1209 if (ret != TRACE_TYPE_HANDLED)
1210 return ret;
1211 break;
1212 default:
1213 event = ftrace_find_event(ent->type);
1214 if (!event)
1215 return TRACE_TYPE_UNHANDLED;
1216
1217 ret = event->funcs->trace(iter, sym_flags, event);
1218 if (ret != TRACE_TYPE_HANDLED)
1219 return ret;
1220 }
1221
1222 if (trace_seq_has_overflowed(s))
1223 goto out;
1224
1225 /* Strip ending newline */
1226 if (s->buffer[s->seq.len - 1] == '\n') {
1227 s->buffer[s->seq.len - 1] = '\0';
1228 s->seq.len--;
1229 }
1230
1231 trace_seq_puts(s, " */\n");
1232 out:
1233 return trace_handle_return(s);
1234}
1235
1236
1237enum print_line_t
1238print_graph_function_flags(struct trace_iterator *iter, u32 flags)
1239{
1240 struct ftrace_graph_ent_entry *field;
1241 struct fgraph_data *data = iter->private;
1242 struct trace_entry *entry = iter->ent;
1243 struct trace_seq *s = &iter->seq;
1244 int cpu = iter->cpu;
1245 int ret;
1246
1247 if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
1248 per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
1249 return TRACE_TYPE_HANDLED;
1250 }
1251
1252 /*
1253 * If the last output failed, there's a possibility we need
1254 * to print out the missing entry which would never go out.
1255 */
1256 if (data && data->failed) {
1257 field = &data->ent;
1258 iter->cpu = data->cpu;
1259 ret = print_graph_entry(field, s, iter, flags);
1260 if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
1261 per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
1262 ret = TRACE_TYPE_NO_CONSUME;
1263 }
1264 iter->cpu = cpu;
1265 return ret;
1266 }
1267
1268 switch (entry->type) {
1269 case TRACE_GRAPH_ENT: {
1270 /*
1271 * print_graph_entry() may consume the current event,
1272 * thus @field may become invalid, so we need to save it.
1273 * sizeof(struct ftrace_graph_ent_entry) is very small,
1274 * it can be safely saved at the stack.
1275 */
1276 struct ftrace_graph_ent_entry saved;
1277 trace_assign_type(field, entry);
1278 saved = *field;
1279 return print_graph_entry(&saved, s, iter, flags);
1280 }
1281 case TRACE_GRAPH_RET: {
1282 struct ftrace_graph_ret_entry *field;
1283 trace_assign_type(field, entry);
1284 return print_graph_return(&field->ret, s, entry, iter, flags);
1285 }
1286 case TRACE_STACK:
1287 case TRACE_FN:
1288 /* dont trace stack and functions as comments */
1289 return TRACE_TYPE_UNHANDLED;
1290
1291 default:
1292 return print_graph_comment(s, entry, iter, flags);
1293 }
1294
1295 return TRACE_TYPE_HANDLED;
1296}
1297
1298static enum print_line_t
1299print_graph_function(struct trace_iterator *iter)
1300{
1301 return print_graph_function_flags(iter, tracer_flags.val);
1302}
1303
1304static enum print_line_t
1305print_graph_function_event(struct trace_iterator *iter, int flags,
1306 struct trace_event *event)
1307{
1308 return print_graph_function(iter);
1309}
1310
1311static void print_lat_header(struct seq_file *s, u32 flags)
1312{
1313 static const char spaces[] = " " /* 16 spaces */
1314 " " /* 4 spaces */
1315 " "; /* 17 spaces */
1316 int size = 0;
1317
1318 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1319 size += 16;
1320 if (flags & TRACE_GRAPH_PRINT_CPU)
1321 size += 4;
1322 if (flags & TRACE_GRAPH_PRINT_PROC)
1323 size += 17;
1324
1325 seq_printf(s, "#%.*s _-----=> irqs-off \n", size, spaces);
1326 seq_printf(s, "#%.*s / _----=> need-resched \n", size, spaces);
1327 seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
1328 seq_printf(s, "#%.*s|| / _--=> preempt-depth \n", size, spaces);
1329 seq_printf(s, "#%.*s||| / \n", size, spaces);
1330}
1331
1332static void __print_graph_headers_flags(struct trace_array *tr,
1333 struct seq_file *s, u32 flags)
1334{
1335 int lat = tr->trace_flags & TRACE_ITER_LATENCY_FMT;
1336
1337 if (lat)
1338 print_lat_header(s, flags);
1339
1340 /* 1st line */
1341 seq_putc(s, '#');
1342 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1343 seq_puts(s, " TIME ");
1344 if (flags & TRACE_GRAPH_PRINT_CPU)
1345 seq_puts(s, " CPU");
1346 if (flags & TRACE_GRAPH_PRINT_PROC)
1347 seq_puts(s, " TASK/PID ");
1348 if (lat)
1349 seq_puts(s, "||||");
1350 if (flags & TRACE_GRAPH_PRINT_DURATION)
1351 seq_puts(s, " DURATION ");
1352 seq_puts(s, " FUNCTION CALLS\n");
1353
1354 /* 2nd line */
1355 seq_putc(s, '#');
1356 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1357 seq_puts(s, " | ");
1358 if (flags & TRACE_GRAPH_PRINT_CPU)
1359 seq_puts(s, " | ");
1360 if (flags & TRACE_GRAPH_PRINT_PROC)
1361 seq_puts(s, " | | ");
1362 if (lat)
1363 seq_puts(s, "||||");
1364 if (flags & TRACE_GRAPH_PRINT_DURATION)
1365 seq_puts(s, " | | ");
1366 seq_puts(s, " | | | |\n");
1367}
1368
1369static void print_graph_headers(struct seq_file *s)
1370{
1371 print_graph_headers_flags(s, tracer_flags.val);
1372}
1373
1374void print_graph_headers_flags(struct seq_file *s, u32 flags)
1375{
1376 struct trace_iterator *iter = s->private;
1377 struct trace_array *tr = iter->tr;
1378
1379 if (!(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
1380 return;
1381
1382 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT) {
1383 /* print nothing if the buffers are empty */
1384 if (trace_empty(iter))
1385 return;
1386
1387 print_trace_header(s, iter);
1388 }
1389
1390 __print_graph_headers_flags(tr, s, flags);
1391}
1392
1393void graph_trace_open(struct trace_iterator *iter)
1394{
1395 /* pid and depth on the last trace processed */
1396 struct fgraph_data *data;
1397 gfp_t gfpflags;
1398 int cpu;
1399
1400 iter->private = NULL;
1401
1402 /* We can be called in atomic context via ftrace_dump() */
1403 gfpflags = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL;
1404
1405 data = kzalloc(sizeof(*data), gfpflags);
1406 if (!data)
1407 goto out_err;
1408
1409 data->cpu_data = alloc_percpu_gfp(struct fgraph_cpu_data, gfpflags);
1410 if (!data->cpu_data)
1411 goto out_err_free;
1412
1413 for_each_possible_cpu(cpu) {
1414 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
1415 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
1416 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
1417 int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1418
1419 *pid = -1;
1420 *depth = 0;
1421 *ignore = 0;
1422 *depth_irq = -1;
1423 }
1424
1425 iter->private = data;
1426
1427 return;
1428
1429 out_err_free:
1430 kfree(data);
1431 out_err:
1432 pr_warn("function graph tracer: not enough memory\n");
1433}
1434
1435void graph_trace_close(struct trace_iterator *iter)
1436{
1437 struct fgraph_data *data = iter->private;
1438
1439 if (data) {
1440 free_percpu(data->cpu_data);
1441 kfree(data);
1442 }
1443}
1444
1445static int
1446func_graph_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1447{
1448 if (bit == TRACE_GRAPH_PRINT_IRQS)
1449 ftrace_graph_skip_irqs = !set;
1450
1451 if (bit == TRACE_GRAPH_SLEEP_TIME)
1452 ftrace_graph_sleep_time_control(set);
1453
1454 if (bit == TRACE_GRAPH_GRAPH_TIME)
1455 ftrace_graph_graph_time_control(set);
1456
1457 return 0;
1458}
1459
1460static struct trace_event_functions graph_functions = {
1461 .trace = print_graph_function_event,
1462};
1463
1464static struct trace_event graph_trace_entry_event = {
1465 .type = TRACE_GRAPH_ENT,
1466 .funcs = &graph_functions,
1467};
1468
1469static struct trace_event graph_trace_ret_event = {
1470 .type = TRACE_GRAPH_RET,
1471 .funcs = &graph_functions
1472};
1473
1474static struct tracer graph_trace __tracer_data = {
1475 .name = "function_graph",
1476 .update_thresh = graph_trace_update_thresh,
1477 .open = graph_trace_open,
1478 .pipe_open = graph_trace_open,
1479 .close = graph_trace_close,
1480 .pipe_close = graph_trace_close,
1481 .init = graph_trace_init,
1482 .reset = graph_trace_reset,
1483 .print_line = print_graph_function,
1484 .print_header = print_graph_headers,
1485 .flags = &tracer_flags,
1486 .set_flag = func_graph_set_flag,
1487#ifdef CONFIG_FTRACE_SELFTEST
1488 .selftest = trace_selftest_startup_function_graph,
1489#endif
1490};
1491
1492
1493static ssize_t
1494graph_depth_write(struct file *filp, const char __user *ubuf, size_t cnt,
1495 loff_t *ppos)
1496{
1497 unsigned long val;
1498 int ret;
1499
1500 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1501 if (ret)
1502 return ret;
1503
1504 fgraph_max_depth = val;
1505
1506 *ppos += cnt;
1507
1508 return cnt;
1509}
1510
1511static ssize_t
1512graph_depth_read(struct file *filp, char __user *ubuf, size_t cnt,
1513 loff_t *ppos)
1514{
1515 char buf[15]; /* More than enough to hold UINT_MAX + "\n"*/
1516 int n;
1517
1518 n = sprintf(buf, "%d\n", fgraph_max_depth);
1519
1520 return simple_read_from_buffer(ubuf, cnt, ppos, buf, n);
1521}
1522
1523static const struct file_operations graph_depth_fops = {
1524 .open = tracing_open_generic,
1525 .write = graph_depth_write,
1526 .read = graph_depth_read,
1527 .llseek = generic_file_llseek,
1528};
1529
1530static __init int init_graph_tracefs(void)
1531{
1532 struct dentry *d_tracer;
1533
1534 d_tracer = tracing_init_dentry();
1535 if (IS_ERR(d_tracer))
1536 return 0;
1537
1538 trace_create_file("max_graph_depth", 0644, d_tracer,
1539 NULL, &graph_depth_fops);
1540
1541 return 0;
1542}
1543fs_initcall(init_graph_tracefs);
1544
1545static __init int init_graph_trace(void)
1546{
1547 max_bytes_for_cpu = snprintf(NULL, 0, "%u", nr_cpu_ids - 1);
1548
1549 if (!register_trace_event(&graph_trace_entry_event)) {
1550 pr_warn("Warning: could not register graph trace events\n");
1551 return 1;
1552 }
1553
1554 if (!register_trace_event(&graph_trace_ret_event)) {
1555 pr_warn("Warning: could not register graph trace events\n");
1556 return 1;
1557 }
1558
1559 return register_tracer(&graph_trace);
1560}
1561
1562core_initcall(init_graph_trace);