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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/*
2 *
3 * Function graph tracer.
4 * Copyright (c) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com>
5 * Mostly borrowed from function tracer which
6 * is Copyright (c) Steven Rostedt <srostedt@redhat.com>
7 *
8 */
9#include <linux/debugfs.h>
10#include <linux/uaccess.h>
11#include <linux/ftrace.h>
12#include <linux/slab.h>
13#include <linux/fs.h>
14
15#include "trace.h"
16#include "trace_output.h"
17
18/* When set, irq functions will be ignored */
19static int ftrace_graph_skip_irqs;
20
21struct fgraph_cpu_data {
22 pid_t last_pid;
23 int depth;
24 int depth_irq;
25 int ignore;
26 unsigned long enter_funcs[FTRACE_RETFUNC_DEPTH];
27};
28
29struct fgraph_data {
30 struct fgraph_cpu_data __percpu *cpu_data;
31
32 /* Place to preserve last processed entry. */
33 struct ftrace_graph_ent_entry ent;
34 struct ftrace_graph_ret_entry ret;
35 int failed;
36 int cpu;
37};
38
39#define TRACE_GRAPH_INDENT 2
40
41/* Flag options */
42#define TRACE_GRAPH_PRINT_OVERRUN 0x1
43#define TRACE_GRAPH_PRINT_CPU 0x2
44#define TRACE_GRAPH_PRINT_OVERHEAD 0x4
45#define TRACE_GRAPH_PRINT_PROC 0x8
46#define TRACE_GRAPH_PRINT_DURATION 0x10
47#define TRACE_GRAPH_PRINT_ABS_TIME 0x20
48#define TRACE_GRAPH_PRINT_IRQS 0x40
49
50static unsigned int max_depth;
51
52static struct tracer_opt trace_opts[] = {
53 /* Display overruns? (for self-debug purpose) */
54 { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
55 /* Display CPU ? */
56 { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
57 /* Display Overhead ? */
58 { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
59 /* Display proc name/pid */
60 { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
61 /* Display duration of execution */
62 { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
63 /* Display absolute time of an entry */
64 { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
65 /* Display interrupts */
66 { TRACER_OPT(funcgraph-irqs, TRACE_GRAPH_PRINT_IRQS) },
67 { } /* Empty entry */
68};
69
70static struct tracer_flags tracer_flags = {
71 /* Don't display overruns and proc by default */
72 .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
73 TRACE_GRAPH_PRINT_DURATION | TRACE_GRAPH_PRINT_IRQS,
74 .opts = trace_opts
75};
76
77static struct trace_array *graph_array;
78
79/*
80 * DURATION column is being also used to display IRQ signs,
81 * following values are used by print_graph_irq and others
82 * to fill in space into DURATION column.
83 */
84enum {
85 FLAGS_FILL_FULL = 1 << TRACE_GRAPH_PRINT_FILL_SHIFT,
86 FLAGS_FILL_START = 2 << TRACE_GRAPH_PRINT_FILL_SHIFT,
87 FLAGS_FILL_END = 3 << TRACE_GRAPH_PRINT_FILL_SHIFT,
88};
89
90static enum print_line_t
91print_graph_duration(unsigned long long duration, struct trace_seq *s,
92 u32 flags);
93
94/* Add a function return address to the trace stack on thread info.*/
95int
96ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
97 unsigned long frame_pointer)
98{
99 unsigned long long calltime;
100 int index;
101
102 if (!current->ret_stack)
103 return -EBUSY;
104
105 /*
106 * We must make sure the ret_stack is tested before we read
107 * anything else.
108 */
109 smp_rmb();
110
111 /* The return trace stack is full */
112 if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
113 atomic_inc(¤t->trace_overrun);
114 return -EBUSY;
115 }
116
117 /*
118 * The curr_ret_stack is an index to ftrace return stack of
119 * current task. Its value should be in [0, FTRACE_RETFUNC_
120 * DEPTH) when the function graph tracer is used. To support
121 * filtering out specific functions, it makes the index
122 * negative by subtracting huge value (FTRACE_NOTRACE_DEPTH)
123 * so when it sees a negative index the ftrace will ignore
124 * the record. And the index gets recovered when returning
125 * from the filtered function by adding the FTRACE_NOTRACE_
126 * DEPTH and then it'll continue to record functions normally.
127 *
128 * The curr_ret_stack is initialized to -1 and get increased
129 * in this function. So it can be less than -1 only if it was
130 * filtered out via ftrace_graph_notrace_addr() which can be
131 * set from set_graph_notrace file in debugfs by user.
132 */
133 if (current->curr_ret_stack < -1)
134 return -EBUSY;
135
136 calltime = trace_clock_local();
137
138 index = ++current->curr_ret_stack;
139 if (ftrace_graph_notrace_addr(func))
140 current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH;
141 barrier();
142 current->ret_stack[index].ret = ret;
143 current->ret_stack[index].func = func;
144 current->ret_stack[index].calltime = calltime;
145 current->ret_stack[index].subtime = 0;
146 current->ret_stack[index].fp = frame_pointer;
147 *depth = current->curr_ret_stack;
148
149 return 0;
150}
151
152/* Retrieve a function return address to the trace stack on thread info.*/
153static void
154ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
155 unsigned long frame_pointer)
156{
157 int index;
158
159 index = current->curr_ret_stack;
160
161 /*
162 * A negative index here means that it's just returned from a
163 * notrace'd function. Recover index to get an original
164 * return address. See ftrace_push_return_trace().
165 *
166 * TODO: Need to check whether the stack gets corrupted.
167 */
168 if (index < 0)
169 index += FTRACE_NOTRACE_DEPTH;
170
171 if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) {
172 ftrace_graph_stop();
173 WARN_ON(1);
174 /* Might as well panic, otherwise we have no where to go */
175 *ret = (unsigned long)panic;
176 return;
177 }
178
179#if defined(CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST) && !defined(CC_USING_FENTRY)
180 /*
181 * The arch may choose to record the frame pointer used
182 * and check it here to make sure that it is what we expect it
183 * to be. If gcc does not set the place holder of the return
184 * address in the frame pointer, and does a copy instead, then
185 * the function graph trace will fail. This test detects this
186 * case.
187 *
188 * Currently, x86_32 with optimize for size (-Os) makes the latest
189 * gcc do the above.
190 *
191 * Note, -mfentry does not use frame pointers, and this test
192 * is not needed if CC_USING_FENTRY is set.
193 */
194 if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
195 ftrace_graph_stop();
196 WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
197 " from func %ps return to %lx\n",
198 current->ret_stack[index].fp,
199 frame_pointer,
200 (void *)current->ret_stack[index].func,
201 current->ret_stack[index].ret);
202 *ret = (unsigned long)panic;
203 return;
204 }
205#endif
206
207 *ret = current->ret_stack[index].ret;
208 trace->func = current->ret_stack[index].func;
209 trace->calltime = current->ret_stack[index].calltime;
210 trace->overrun = atomic_read(¤t->trace_overrun);
211 trace->depth = index;
212}
213
214/*
215 * Send the trace to the ring-buffer.
216 * @return the original return address.
217 */
218unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
219{
220 struct ftrace_graph_ret trace;
221 unsigned long ret;
222
223 ftrace_pop_return_trace(&trace, &ret, frame_pointer);
224 trace.rettime = trace_clock_local();
225 barrier();
226 current->curr_ret_stack--;
227 /*
228 * The curr_ret_stack can be less than -1 only if it was
229 * filtered out and it's about to return from the function.
230 * Recover the index and continue to trace normal functions.
231 */
232 if (current->curr_ret_stack < -1) {
233 current->curr_ret_stack += FTRACE_NOTRACE_DEPTH;
234 return ret;
235 }
236
237 /*
238 * The trace should run after decrementing the ret counter
239 * in case an interrupt were to come in. We don't want to
240 * lose the interrupt if max_depth is set.
241 */
242 ftrace_graph_return(&trace);
243
244 if (unlikely(!ret)) {
245 ftrace_graph_stop();
246 WARN_ON(1);
247 /* Might as well panic. What else to do? */
248 ret = (unsigned long)panic;
249 }
250
251 return ret;
252}
253
254int __trace_graph_entry(struct trace_array *tr,
255 struct ftrace_graph_ent *trace,
256 unsigned long flags,
257 int pc)
258{
259 struct ftrace_event_call *call = &event_funcgraph_entry;
260 struct ring_buffer_event *event;
261 struct ring_buffer *buffer = tr->trace_buffer.buffer;
262 struct ftrace_graph_ent_entry *entry;
263
264 if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
265 return 0;
266
267 event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
268 sizeof(*entry), flags, pc);
269 if (!event)
270 return 0;
271 entry = ring_buffer_event_data(event);
272 entry->graph_ent = *trace;
273 if (!call_filter_check_discard(call, entry, buffer, event))
274 __buffer_unlock_commit(buffer, event);
275
276 return 1;
277}
278
279static inline int ftrace_graph_ignore_irqs(void)
280{
281 if (!ftrace_graph_skip_irqs || trace_recursion_test(TRACE_IRQ_BIT))
282 return 0;
283
284 return in_irq();
285}
286
287int trace_graph_entry(struct ftrace_graph_ent *trace)
288{
289 struct trace_array *tr = graph_array;
290 struct trace_array_cpu *data;
291 unsigned long flags;
292 long disabled;
293 int ret;
294 int cpu;
295 int pc;
296
297 if (!ftrace_trace_task(current))
298 return 0;
299
300 /* trace it when it is-nested-in or is a function enabled. */
301 if ((!(trace->depth || ftrace_graph_addr(trace->func)) ||
302 ftrace_graph_ignore_irqs()) || (trace->depth < 0) ||
303 (max_depth && trace->depth >= max_depth))
304 return 0;
305
306 /*
307 * Do not trace a function if it's filtered by set_graph_notrace.
308 * Make the index of ret stack negative to indicate that it should
309 * ignore further functions. But it needs its own ret stack entry
310 * to recover the original index in order to continue tracing after
311 * returning from the function.
312 */
313 if (ftrace_graph_notrace_addr(trace->func))
314 return 1;
315
316 local_irq_save(flags);
317 cpu = raw_smp_processor_id();
318 data = per_cpu_ptr(tr->trace_buffer.data, cpu);
319 disabled = atomic_inc_return(&data->disabled);
320 if (likely(disabled == 1)) {
321 pc = preempt_count();
322 ret = __trace_graph_entry(tr, trace, flags, pc);
323 } else {
324 ret = 0;
325 }
326
327 atomic_dec(&data->disabled);
328 local_irq_restore(flags);
329
330 return ret;
331}
332
333int trace_graph_thresh_entry(struct ftrace_graph_ent *trace)
334{
335 if (tracing_thresh)
336 return 1;
337 else
338 return trace_graph_entry(trace);
339}
340
341static void
342__trace_graph_function(struct trace_array *tr,
343 unsigned long ip, unsigned long flags, int pc)
344{
345 u64 time = trace_clock_local();
346 struct ftrace_graph_ent ent = {
347 .func = ip,
348 .depth = 0,
349 };
350 struct ftrace_graph_ret ret = {
351 .func = ip,
352 .depth = 0,
353 .calltime = time,
354 .rettime = time,
355 };
356
357 __trace_graph_entry(tr, &ent, flags, pc);
358 __trace_graph_return(tr, &ret, flags, pc);
359}
360
361void
362trace_graph_function(struct trace_array *tr,
363 unsigned long ip, unsigned long parent_ip,
364 unsigned long flags, int pc)
365{
366 __trace_graph_function(tr, ip, flags, pc);
367}
368
369void __trace_graph_return(struct trace_array *tr,
370 struct ftrace_graph_ret *trace,
371 unsigned long flags,
372 int pc)
373{
374 struct ftrace_event_call *call = &event_funcgraph_exit;
375 struct ring_buffer_event *event;
376 struct ring_buffer *buffer = tr->trace_buffer.buffer;
377 struct ftrace_graph_ret_entry *entry;
378
379 if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
380 return;
381
382 event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
383 sizeof(*entry), flags, pc);
384 if (!event)
385 return;
386 entry = ring_buffer_event_data(event);
387 entry->ret = *trace;
388 if (!call_filter_check_discard(call, entry, buffer, event))
389 __buffer_unlock_commit(buffer, event);
390}
391
392void trace_graph_return(struct ftrace_graph_ret *trace)
393{
394 struct trace_array *tr = graph_array;
395 struct trace_array_cpu *data;
396 unsigned long flags;
397 long disabled;
398 int cpu;
399 int pc;
400
401 local_irq_save(flags);
402 cpu = raw_smp_processor_id();
403 data = per_cpu_ptr(tr->trace_buffer.data, cpu);
404 disabled = atomic_inc_return(&data->disabled);
405 if (likely(disabled == 1)) {
406 pc = preempt_count();
407 __trace_graph_return(tr, trace, flags, pc);
408 }
409 atomic_dec(&data->disabled);
410 local_irq_restore(flags);
411}
412
413void set_graph_array(struct trace_array *tr)
414{
415 graph_array = tr;
416
417 /* Make graph_array visible before we start tracing */
418
419 smp_mb();
420}
421
422void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
423{
424 if (tracing_thresh &&
425 (trace->rettime - trace->calltime < tracing_thresh))
426 return;
427 else
428 trace_graph_return(trace);
429}
430
431static int graph_trace_init(struct trace_array *tr)
432{
433 int ret;
434
435 set_graph_array(tr);
436 if (tracing_thresh)
437 ret = register_ftrace_graph(&trace_graph_thresh_return,
438 &trace_graph_thresh_entry);
439 else
440 ret = register_ftrace_graph(&trace_graph_return,
441 &trace_graph_entry);
442 if (ret)
443 return ret;
444 tracing_start_cmdline_record();
445
446 return 0;
447}
448
449static void graph_trace_reset(struct trace_array *tr)
450{
451 tracing_stop_cmdline_record();
452 unregister_ftrace_graph();
453}
454
455static int max_bytes_for_cpu;
456
457static enum print_line_t
458print_graph_cpu(struct trace_seq *s, int cpu)
459{
460 int ret;
461
462 /*
463 * Start with a space character - to make it stand out
464 * to the right a bit when trace output is pasted into
465 * email:
466 */
467 ret = trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
468 if (!ret)
469 return TRACE_TYPE_PARTIAL_LINE;
470
471 return TRACE_TYPE_HANDLED;
472}
473
474#define TRACE_GRAPH_PROCINFO_LENGTH 14
475
476static enum print_line_t
477print_graph_proc(struct trace_seq *s, pid_t pid)
478{
479 char comm[TASK_COMM_LEN];
480 /* sign + log10(MAX_INT) + '\0' */
481 char pid_str[11];
482 int spaces = 0;
483 int ret;
484 int len;
485 int i;
486
487 trace_find_cmdline(pid, comm);
488 comm[7] = '\0';
489 sprintf(pid_str, "%d", pid);
490
491 /* 1 stands for the "-" character */
492 len = strlen(comm) + strlen(pid_str) + 1;
493
494 if (len < TRACE_GRAPH_PROCINFO_LENGTH)
495 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
496
497 /* First spaces to align center */
498 for (i = 0; i < spaces / 2; i++) {
499 ret = trace_seq_putc(s, ' ');
500 if (!ret)
501 return TRACE_TYPE_PARTIAL_LINE;
502 }
503
504 ret = trace_seq_printf(s, "%s-%s", comm, pid_str);
505 if (!ret)
506 return TRACE_TYPE_PARTIAL_LINE;
507
508 /* Last spaces to align center */
509 for (i = 0; i < spaces - (spaces / 2); i++) {
510 ret = trace_seq_putc(s, ' ');
511 if (!ret)
512 return TRACE_TYPE_PARTIAL_LINE;
513 }
514 return TRACE_TYPE_HANDLED;
515}
516
517
518static enum print_line_t
519print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
520{
521 if (!trace_seq_putc(s, ' '))
522 return 0;
523
524 return trace_print_lat_fmt(s, entry);
525}
526
527/* If the pid changed since the last trace, output this event */
528static enum print_line_t
529verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
530{
531 pid_t prev_pid;
532 pid_t *last_pid;
533 int ret;
534
535 if (!data)
536 return TRACE_TYPE_HANDLED;
537
538 last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
539
540 if (*last_pid == pid)
541 return TRACE_TYPE_HANDLED;
542
543 prev_pid = *last_pid;
544 *last_pid = pid;
545
546 if (prev_pid == -1)
547 return TRACE_TYPE_HANDLED;
548/*
549 * Context-switch trace line:
550
551 ------------------------------------------
552 | 1) migration/0--1 => sshd-1755
553 ------------------------------------------
554
555 */
556 ret = trace_seq_puts(s,
557 " ------------------------------------------\n");
558 if (!ret)
559 return TRACE_TYPE_PARTIAL_LINE;
560
561 ret = print_graph_cpu(s, cpu);
562 if (ret == TRACE_TYPE_PARTIAL_LINE)
563 return TRACE_TYPE_PARTIAL_LINE;
564
565 ret = print_graph_proc(s, prev_pid);
566 if (ret == TRACE_TYPE_PARTIAL_LINE)
567 return TRACE_TYPE_PARTIAL_LINE;
568
569 ret = trace_seq_puts(s, " => ");
570 if (!ret)
571 return TRACE_TYPE_PARTIAL_LINE;
572
573 ret = print_graph_proc(s, pid);
574 if (ret == TRACE_TYPE_PARTIAL_LINE)
575 return TRACE_TYPE_PARTIAL_LINE;
576
577 ret = trace_seq_puts(s,
578 "\n ------------------------------------------\n\n");
579 if (!ret)
580 return TRACE_TYPE_PARTIAL_LINE;
581
582 return TRACE_TYPE_HANDLED;
583}
584
585static struct ftrace_graph_ret_entry *
586get_return_for_leaf(struct trace_iterator *iter,
587 struct ftrace_graph_ent_entry *curr)
588{
589 struct fgraph_data *data = iter->private;
590 struct ring_buffer_iter *ring_iter = NULL;
591 struct ring_buffer_event *event;
592 struct ftrace_graph_ret_entry *next;
593
594 /*
595 * If the previous output failed to write to the seq buffer,
596 * then we just reuse the data from before.
597 */
598 if (data && data->failed) {
599 curr = &data->ent;
600 next = &data->ret;
601 } else {
602
603 ring_iter = trace_buffer_iter(iter, iter->cpu);
604
605 /* First peek to compare current entry and the next one */
606 if (ring_iter)
607 event = ring_buffer_iter_peek(ring_iter, NULL);
608 else {
609 /*
610 * We need to consume the current entry to see
611 * the next one.
612 */
613 ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu,
614 NULL, NULL);
615 event = ring_buffer_peek(iter->trace_buffer->buffer, iter->cpu,
616 NULL, NULL);
617 }
618
619 if (!event)
620 return NULL;
621
622 next = ring_buffer_event_data(event);
623
624 if (data) {
625 /*
626 * Save current and next entries for later reference
627 * if the output fails.
628 */
629 data->ent = *curr;
630 /*
631 * If the next event is not a return type, then
632 * we only care about what type it is. Otherwise we can
633 * safely copy the entire event.
634 */
635 if (next->ent.type == TRACE_GRAPH_RET)
636 data->ret = *next;
637 else
638 data->ret.ent.type = next->ent.type;
639 }
640 }
641
642 if (next->ent.type != TRACE_GRAPH_RET)
643 return NULL;
644
645 if (curr->ent.pid != next->ent.pid ||
646 curr->graph_ent.func != next->ret.func)
647 return NULL;
648
649 /* this is a leaf, now advance the iterator */
650 if (ring_iter)
651 ring_buffer_read(ring_iter, NULL);
652
653 return next;
654}
655
656static int print_graph_abs_time(u64 t, struct trace_seq *s)
657{
658 unsigned long usecs_rem;
659
660 usecs_rem = do_div(t, NSEC_PER_SEC);
661 usecs_rem /= 1000;
662
663 return trace_seq_printf(s, "%5lu.%06lu | ",
664 (unsigned long)t, usecs_rem);
665}
666
667static enum print_line_t
668print_graph_irq(struct trace_iterator *iter, unsigned long addr,
669 enum trace_type type, int cpu, pid_t pid, u32 flags)
670{
671 int ret;
672 struct trace_seq *s = &iter->seq;
673
674 if (addr < (unsigned long)__irqentry_text_start ||
675 addr >= (unsigned long)__irqentry_text_end)
676 return TRACE_TYPE_UNHANDLED;
677
678 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
679 /* Absolute time */
680 if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {
681 ret = print_graph_abs_time(iter->ts, s);
682 if (!ret)
683 return TRACE_TYPE_PARTIAL_LINE;
684 }
685
686 /* Cpu */
687 if (flags & TRACE_GRAPH_PRINT_CPU) {
688 ret = print_graph_cpu(s, cpu);
689 if (ret == TRACE_TYPE_PARTIAL_LINE)
690 return TRACE_TYPE_PARTIAL_LINE;
691 }
692
693 /* Proc */
694 if (flags & TRACE_GRAPH_PRINT_PROC) {
695 ret = print_graph_proc(s, pid);
696 if (ret == TRACE_TYPE_PARTIAL_LINE)
697 return TRACE_TYPE_PARTIAL_LINE;
698 ret = trace_seq_puts(s, " | ");
699 if (!ret)
700 return TRACE_TYPE_PARTIAL_LINE;
701 }
702 }
703
704 /* No overhead */
705 ret = print_graph_duration(0, s, flags | FLAGS_FILL_START);
706 if (ret != TRACE_TYPE_HANDLED)
707 return ret;
708
709 if (type == TRACE_GRAPH_ENT)
710 ret = trace_seq_puts(s, "==========>");
711 else
712 ret = trace_seq_puts(s, "<==========");
713
714 if (!ret)
715 return TRACE_TYPE_PARTIAL_LINE;
716
717 ret = print_graph_duration(0, s, flags | FLAGS_FILL_END);
718 if (ret != TRACE_TYPE_HANDLED)
719 return ret;
720
721 ret = trace_seq_putc(s, '\n');
722
723 if (!ret)
724 return TRACE_TYPE_PARTIAL_LINE;
725 return TRACE_TYPE_HANDLED;
726}
727
728enum print_line_t
729trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
730{
731 unsigned long nsecs_rem = do_div(duration, 1000);
732 /* log10(ULONG_MAX) + '\0' */
733 char msecs_str[21];
734 char nsecs_str[5];
735 int ret, len;
736 int i;
737
738 sprintf(msecs_str, "%lu", (unsigned long) duration);
739
740 /* Print msecs */
741 ret = trace_seq_printf(s, "%s", msecs_str);
742 if (!ret)
743 return TRACE_TYPE_PARTIAL_LINE;
744
745 len = strlen(msecs_str);
746
747 /* Print nsecs (we don't want to exceed 7 numbers) */
748 if (len < 7) {
749 size_t slen = min_t(size_t, sizeof(nsecs_str), 8UL - len);
750
751 snprintf(nsecs_str, slen, "%03lu", nsecs_rem);
752 ret = trace_seq_printf(s, ".%s", nsecs_str);
753 if (!ret)
754 return TRACE_TYPE_PARTIAL_LINE;
755 len += strlen(nsecs_str);
756 }
757
758 ret = trace_seq_puts(s, " us ");
759 if (!ret)
760 return TRACE_TYPE_PARTIAL_LINE;
761
762 /* Print remaining spaces to fit the row's width */
763 for (i = len; i < 7; i++) {
764 ret = trace_seq_putc(s, ' ');
765 if (!ret)
766 return TRACE_TYPE_PARTIAL_LINE;
767 }
768 return TRACE_TYPE_HANDLED;
769}
770
771static enum print_line_t
772print_graph_duration(unsigned long long duration, struct trace_seq *s,
773 u32 flags)
774{
775 int ret = -1;
776
777 if (!(flags & TRACE_GRAPH_PRINT_DURATION) ||
778 !(trace_flags & TRACE_ITER_CONTEXT_INFO))
779 return TRACE_TYPE_HANDLED;
780
781 /* No real adata, just filling the column with spaces */
782 switch (flags & TRACE_GRAPH_PRINT_FILL_MASK) {
783 case FLAGS_FILL_FULL:
784 ret = trace_seq_puts(s, " | ");
785 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
786 case FLAGS_FILL_START:
787 ret = trace_seq_puts(s, " ");
788 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
789 case FLAGS_FILL_END:
790 ret = trace_seq_puts(s, " |");
791 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
792 }
793
794 /* Signal a overhead of time execution to the output */
795 if (flags & TRACE_GRAPH_PRINT_OVERHEAD) {
796 /* Duration exceeded 100 msecs */
797 if (duration > 100000ULL)
798 ret = trace_seq_puts(s, "! ");
799 /* Duration exceeded 10 msecs */
800 else if (duration > 10000ULL)
801 ret = trace_seq_puts(s, "+ ");
802 }
803
804 /*
805 * The -1 means we either did not exceed the duration tresholds
806 * or we dont want to print out the overhead. Either way we need
807 * to fill out the space.
808 */
809 if (ret == -1)
810 ret = trace_seq_puts(s, " ");
811
812 /* Catching here any failure happenned above */
813 if (!ret)
814 return TRACE_TYPE_PARTIAL_LINE;
815
816 ret = trace_print_graph_duration(duration, s);
817 if (ret != TRACE_TYPE_HANDLED)
818 return ret;
819
820 ret = trace_seq_puts(s, "| ");
821 if (!ret)
822 return TRACE_TYPE_PARTIAL_LINE;
823
824 return TRACE_TYPE_HANDLED;
825}
826
827/* Case of a leaf function on its call entry */
828static enum print_line_t
829print_graph_entry_leaf(struct trace_iterator *iter,
830 struct ftrace_graph_ent_entry *entry,
831 struct ftrace_graph_ret_entry *ret_entry,
832 struct trace_seq *s, u32 flags)
833{
834 struct fgraph_data *data = iter->private;
835 struct ftrace_graph_ret *graph_ret;
836 struct ftrace_graph_ent *call;
837 unsigned long long duration;
838 int ret;
839 int i;
840
841 graph_ret = &ret_entry->ret;
842 call = &entry->graph_ent;
843 duration = graph_ret->rettime - graph_ret->calltime;
844
845 if (data) {
846 struct fgraph_cpu_data *cpu_data;
847 int cpu = iter->cpu;
848
849 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
850
851 /*
852 * Comments display at + 1 to depth. Since
853 * this is a leaf function, keep the comments
854 * equal to this depth.
855 */
856 cpu_data->depth = call->depth - 1;
857
858 /* No need to keep this function around for this depth */
859 if (call->depth < FTRACE_RETFUNC_DEPTH)
860 cpu_data->enter_funcs[call->depth] = 0;
861 }
862
863 /* Overhead and duration */
864 ret = print_graph_duration(duration, s, flags);
865 if (ret == TRACE_TYPE_PARTIAL_LINE)
866 return TRACE_TYPE_PARTIAL_LINE;
867
868 /* Function */
869 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
870 ret = trace_seq_putc(s, ' ');
871 if (!ret)
872 return TRACE_TYPE_PARTIAL_LINE;
873 }
874
875 ret = trace_seq_printf(s, "%ps();\n", (void *)call->func);
876 if (!ret)
877 return TRACE_TYPE_PARTIAL_LINE;
878
879 return TRACE_TYPE_HANDLED;
880}
881
882static enum print_line_t
883print_graph_entry_nested(struct trace_iterator *iter,
884 struct ftrace_graph_ent_entry *entry,
885 struct trace_seq *s, int cpu, u32 flags)
886{
887 struct ftrace_graph_ent *call = &entry->graph_ent;
888 struct fgraph_data *data = iter->private;
889 int ret;
890 int i;
891
892 if (data) {
893 struct fgraph_cpu_data *cpu_data;
894 int cpu = iter->cpu;
895
896 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
897 cpu_data->depth = call->depth;
898
899 /* Save this function pointer to see if the exit matches */
900 if (call->depth < FTRACE_RETFUNC_DEPTH)
901 cpu_data->enter_funcs[call->depth] = call->func;
902 }
903
904 /* No time */
905 ret = print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
906 if (ret != TRACE_TYPE_HANDLED)
907 return ret;
908
909 /* Function */
910 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
911 ret = trace_seq_putc(s, ' ');
912 if (!ret)
913 return TRACE_TYPE_PARTIAL_LINE;
914 }
915
916 ret = trace_seq_printf(s, "%ps() {\n", (void *)call->func);
917 if (!ret)
918 return TRACE_TYPE_PARTIAL_LINE;
919
920 /*
921 * we already consumed the current entry to check the next one
922 * and see if this is a leaf.
923 */
924 return TRACE_TYPE_NO_CONSUME;
925}
926
927static enum print_line_t
928print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
929 int type, unsigned long addr, u32 flags)
930{
931 struct fgraph_data *data = iter->private;
932 struct trace_entry *ent = iter->ent;
933 int cpu = iter->cpu;
934 int ret;
935
936 /* Pid */
937 if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)
938 return TRACE_TYPE_PARTIAL_LINE;
939
940 if (type) {
941 /* Interrupt */
942 ret = print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
943 if (ret == TRACE_TYPE_PARTIAL_LINE)
944 return TRACE_TYPE_PARTIAL_LINE;
945 }
946
947 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
948 return 0;
949
950 /* Absolute time */
951 if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {
952 ret = print_graph_abs_time(iter->ts, s);
953 if (!ret)
954 return TRACE_TYPE_PARTIAL_LINE;
955 }
956
957 /* Cpu */
958 if (flags & TRACE_GRAPH_PRINT_CPU) {
959 ret = print_graph_cpu(s, cpu);
960 if (ret == TRACE_TYPE_PARTIAL_LINE)
961 return TRACE_TYPE_PARTIAL_LINE;
962 }
963
964 /* Proc */
965 if (flags & TRACE_GRAPH_PRINT_PROC) {
966 ret = print_graph_proc(s, ent->pid);
967 if (ret == TRACE_TYPE_PARTIAL_LINE)
968 return TRACE_TYPE_PARTIAL_LINE;
969
970 ret = trace_seq_puts(s, " | ");
971 if (!ret)
972 return TRACE_TYPE_PARTIAL_LINE;
973 }
974
975 /* Latency format */
976 if (trace_flags & TRACE_ITER_LATENCY_FMT) {
977 ret = print_graph_lat_fmt(s, ent);
978 if (ret == TRACE_TYPE_PARTIAL_LINE)
979 return TRACE_TYPE_PARTIAL_LINE;
980 }
981
982 return 0;
983}
984
985/*
986 * Entry check for irq code
987 *
988 * returns 1 if
989 * - we are inside irq code
990 * - we just entered irq code
991 *
992 * retunns 0 if
993 * - funcgraph-interrupts option is set
994 * - we are not inside irq code
995 */
996static int
997check_irq_entry(struct trace_iterator *iter, u32 flags,
998 unsigned long addr, int depth)
999{
1000 int cpu = iter->cpu;
1001 int *depth_irq;
1002 struct fgraph_data *data = iter->private;
1003
1004 /*
1005 * If we are either displaying irqs, or we got called as
1006 * a graph event and private data does not exist,
1007 * then we bypass the irq check.
1008 */
1009 if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
1010 (!data))
1011 return 0;
1012
1013 depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1014
1015 /*
1016 * We are inside the irq code
1017 */
1018 if (*depth_irq >= 0)
1019 return 1;
1020
1021 if ((addr < (unsigned long)__irqentry_text_start) ||
1022 (addr >= (unsigned long)__irqentry_text_end))
1023 return 0;
1024
1025 /*
1026 * We are entering irq code.
1027 */
1028 *depth_irq = depth;
1029 return 1;
1030}
1031
1032/*
1033 * Return check for irq code
1034 *
1035 * returns 1 if
1036 * - we are inside irq code
1037 * - we just left irq code
1038 *
1039 * returns 0 if
1040 * - funcgraph-interrupts option is set
1041 * - we are not inside irq code
1042 */
1043static int
1044check_irq_return(struct trace_iterator *iter, u32 flags, int depth)
1045{
1046 int cpu = iter->cpu;
1047 int *depth_irq;
1048 struct fgraph_data *data = iter->private;
1049
1050 /*
1051 * If we are either displaying irqs, or we got called as
1052 * a graph event and private data does not exist,
1053 * then we bypass the irq check.
1054 */
1055 if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
1056 (!data))
1057 return 0;
1058
1059 depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1060
1061 /*
1062 * We are not inside the irq code.
1063 */
1064 if (*depth_irq == -1)
1065 return 0;
1066
1067 /*
1068 * We are inside the irq code, and this is returning entry.
1069 * Let's not trace it and clear the entry depth, since
1070 * we are out of irq code.
1071 *
1072 * This condition ensures that we 'leave the irq code' once
1073 * we are out of the entry depth. Thus protecting us from
1074 * the RETURN entry loss.
1075 */
1076 if (*depth_irq >= depth) {
1077 *depth_irq = -1;
1078 return 1;
1079 }
1080
1081 /*
1082 * We are inside the irq code, and this is not the entry.
1083 */
1084 return 1;
1085}
1086
1087static enum print_line_t
1088print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
1089 struct trace_iterator *iter, u32 flags)
1090{
1091 struct fgraph_data *data = iter->private;
1092 struct ftrace_graph_ent *call = &field->graph_ent;
1093 struct ftrace_graph_ret_entry *leaf_ret;
1094 static enum print_line_t ret;
1095 int cpu = iter->cpu;
1096
1097 if (check_irq_entry(iter, flags, call->func, call->depth))
1098 return TRACE_TYPE_HANDLED;
1099
1100 if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags))
1101 return TRACE_TYPE_PARTIAL_LINE;
1102
1103 leaf_ret = get_return_for_leaf(iter, field);
1104 if (leaf_ret)
1105 ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags);
1106 else
1107 ret = print_graph_entry_nested(iter, field, s, cpu, flags);
1108
1109 if (data) {
1110 /*
1111 * If we failed to write our output, then we need to make
1112 * note of it. Because we already consumed our entry.
1113 */
1114 if (s->full) {
1115 data->failed = 1;
1116 data->cpu = cpu;
1117 } else
1118 data->failed = 0;
1119 }
1120
1121 return ret;
1122}
1123
1124static enum print_line_t
1125print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
1126 struct trace_entry *ent, struct trace_iterator *iter,
1127 u32 flags)
1128{
1129 unsigned long long duration = trace->rettime - trace->calltime;
1130 struct fgraph_data *data = iter->private;
1131 pid_t pid = ent->pid;
1132 int cpu = iter->cpu;
1133 int func_match = 1;
1134 int ret;
1135 int i;
1136
1137 if (check_irq_return(iter, flags, trace->depth))
1138 return TRACE_TYPE_HANDLED;
1139
1140 if (data) {
1141 struct fgraph_cpu_data *cpu_data;
1142 int cpu = iter->cpu;
1143
1144 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
1145
1146 /*
1147 * Comments display at + 1 to depth. This is the
1148 * return from a function, we now want the comments
1149 * to display at the same level of the bracket.
1150 */
1151 cpu_data->depth = trace->depth - 1;
1152
1153 if (trace->depth < FTRACE_RETFUNC_DEPTH) {
1154 if (cpu_data->enter_funcs[trace->depth] != trace->func)
1155 func_match = 0;
1156 cpu_data->enter_funcs[trace->depth] = 0;
1157 }
1158 }
1159
1160 if (print_graph_prologue(iter, s, 0, 0, flags))
1161 return TRACE_TYPE_PARTIAL_LINE;
1162
1163 /* Overhead and duration */
1164 ret = print_graph_duration(duration, s, flags);
1165 if (ret == TRACE_TYPE_PARTIAL_LINE)
1166 return TRACE_TYPE_PARTIAL_LINE;
1167
1168 /* Closing brace */
1169 for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
1170 ret = trace_seq_putc(s, ' ');
1171 if (!ret)
1172 return TRACE_TYPE_PARTIAL_LINE;
1173 }
1174
1175 /*
1176 * If the return function does not have a matching entry,
1177 * then the entry was lost. Instead of just printing
1178 * the '}' and letting the user guess what function this
1179 * belongs to, write out the function name.
1180 */
1181 if (func_match) {
1182 ret = trace_seq_puts(s, "}\n");
1183 if (!ret)
1184 return TRACE_TYPE_PARTIAL_LINE;
1185 } else {
1186 ret = trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
1187 if (!ret)
1188 return TRACE_TYPE_PARTIAL_LINE;
1189 }
1190
1191 /* Overrun */
1192 if (flags & TRACE_GRAPH_PRINT_OVERRUN) {
1193 ret = trace_seq_printf(s, " (Overruns: %lu)\n",
1194 trace->overrun);
1195 if (!ret)
1196 return TRACE_TYPE_PARTIAL_LINE;
1197 }
1198
1199 ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
1200 cpu, pid, flags);
1201 if (ret == TRACE_TYPE_PARTIAL_LINE)
1202 return TRACE_TYPE_PARTIAL_LINE;
1203
1204 return TRACE_TYPE_HANDLED;
1205}
1206
1207static enum print_line_t
1208print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
1209 struct trace_iterator *iter, u32 flags)
1210{
1211 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1212 struct fgraph_data *data = iter->private;
1213 struct trace_event *event;
1214 int depth = 0;
1215 int ret;
1216 int i;
1217
1218 if (data)
1219 depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
1220
1221 if (print_graph_prologue(iter, s, 0, 0, flags))
1222 return TRACE_TYPE_PARTIAL_LINE;
1223
1224 /* No time */
1225 ret = print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
1226 if (ret != TRACE_TYPE_HANDLED)
1227 return ret;
1228
1229 /* Indentation */
1230 if (depth > 0)
1231 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) {
1232 ret = trace_seq_putc(s, ' ');
1233 if (!ret)
1234 return TRACE_TYPE_PARTIAL_LINE;
1235 }
1236
1237 /* The comment */
1238 ret = trace_seq_puts(s, "/* ");
1239 if (!ret)
1240 return TRACE_TYPE_PARTIAL_LINE;
1241
1242 switch (iter->ent->type) {
1243 case TRACE_BPRINT:
1244 ret = trace_print_bprintk_msg_only(iter);
1245 if (ret != TRACE_TYPE_HANDLED)
1246 return ret;
1247 break;
1248 case TRACE_PRINT:
1249 ret = trace_print_printk_msg_only(iter);
1250 if (ret != TRACE_TYPE_HANDLED)
1251 return ret;
1252 break;
1253 default:
1254 event = ftrace_find_event(ent->type);
1255 if (!event)
1256 return TRACE_TYPE_UNHANDLED;
1257
1258 ret = event->funcs->trace(iter, sym_flags, event);
1259 if (ret != TRACE_TYPE_HANDLED)
1260 return ret;
1261 }
1262
1263 /* Strip ending newline */
1264 if (s->buffer[s->len - 1] == '\n') {
1265 s->buffer[s->len - 1] = '\0';
1266 s->len--;
1267 }
1268
1269 ret = trace_seq_puts(s, " */\n");
1270 if (!ret)
1271 return TRACE_TYPE_PARTIAL_LINE;
1272
1273 return TRACE_TYPE_HANDLED;
1274}
1275
1276
1277enum print_line_t
1278print_graph_function_flags(struct trace_iterator *iter, u32 flags)
1279{
1280 struct ftrace_graph_ent_entry *field;
1281 struct fgraph_data *data = iter->private;
1282 struct trace_entry *entry = iter->ent;
1283 struct trace_seq *s = &iter->seq;
1284 int cpu = iter->cpu;
1285 int ret;
1286
1287 if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
1288 per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
1289 return TRACE_TYPE_HANDLED;
1290 }
1291
1292 /*
1293 * If the last output failed, there's a possibility we need
1294 * to print out the missing entry which would never go out.
1295 */
1296 if (data && data->failed) {
1297 field = &data->ent;
1298 iter->cpu = data->cpu;
1299 ret = print_graph_entry(field, s, iter, flags);
1300 if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
1301 per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
1302 ret = TRACE_TYPE_NO_CONSUME;
1303 }
1304 iter->cpu = cpu;
1305 return ret;
1306 }
1307
1308 switch (entry->type) {
1309 case TRACE_GRAPH_ENT: {
1310 /*
1311 * print_graph_entry() may consume the current event,
1312 * thus @field may become invalid, so we need to save it.
1313 * sizeof(struct ftrace_graph_ent_entry) is very small,
1314 * it can be safely saved at the stack.
1315 */
1316 struct ftrace_graph_ent_entry saved;
1317 trace_assign_type(field, entry);
1318 saved = *field;
1319 return print_graph_entry(&saved, s, iter, flags);
1320 }
1321 case TRACE_GRAPH_RET: {
1322 struct ftrace_graph_ret_entry *field;
1323 trace_assign_type(field, entry);
1324 return print_graph_return(&field->ret, s, entry, iter, flags);
1325 }
1326 case TRACE_STACK:
1327 case TRACE_FN:
1328 /* dont trace stack and functions as comments */
1329 return TRACE_TYPE_UNHANDLED;
1330
1331 default:
1332 return print_graph_comment(s, entry, iter, flags);
1333 }
1334
1335 return TRACE_TYPE_HANDLED;
1336}
1337
1338static enum print_line_t
1339print_graph_function(struct trace_iterator *iter)
1340{
1341 return print_graph_function_flags(iter, tracer_flags.val);
1342}
1343
1344static enum print_line_t
1345print_graph_function_event(struct trace_iterator *iter, int flags,
1346 struct trace_event *event)
1347{
1348 return print_graph_function(iter);
1349}
1350
1351static void print_lat_header(struct seq_file *s, u32 flags)
1352{
1353 static const char spaces[] = " " /* 16 spaces */
1354 " " /* 4 spaces */
1355 " "; /* 17 spaces */
1356 int size = 0;
1357
1358 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1359 size += 16;
1360 if (flags & TRACE_GRAPH_PRINT_CPU)
1361 size += 4;
1362 if (flags & TRACE_GRAPH_PRINT_PROC)
1363 size += 17;
1364
1365 seq_printf(s, "#%.*s _-----=> irqs-off \n", size, spaces);
1366 seq_printf(s, "#%.*s / _----=> need-resched \n", size, spaces);
1367 seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
1368 seq_printf(s, "#%.*s|| / _--=> preempt-depth \n", size, spaces);
1369 seq_printf(s, "#%.*s||| / \n", size, spaces);
1370}
1371
1372static void __print_graph_headers_flags(struct seq_file *s, u32 flags)
1373{
1374 int lat = trace_flags & TRACE_ITER_LATENCY_FMT;
1375
1376 if (lat)
1377 print_lat_header(s, flags);
1378
1379 /* 1st line */
1380 seq_printf(s, "#");
1381 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1382 seq_printf(s, " TIME ");
1383 if (flags & TRACE_GRAPH_PRINT_CPU)
1384 seq_printf(s, " CPU");
1385 if (flags & TRACE_GRAPH_PRINT_PROC)
1386 seq_printf(s, " TASK/PID ");
1387 if (lat)
1388 seq_printf(s, "||||");
1389 if (flags & TRACE_GRAPH_PRINT_DURATION)
1390 seq_printf(s, " DURATION ");
1391 seq_printf(s, " FUNCTION CALLS\n");
1392
1393 /* 2nd line */
1394 seq_printf(s, "#");
1395 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1396 seq_printf(s, " | ");
1397 if (flags & TRACE_GRAPH_PRINT_CPU)
1398 seq_printf(s, " | ");
1399 if (flags & TRACE_GRAPH_PRINT_PROC)
1400 seq_printf(s, " | | ");
1401 if (lat)
1402 seq_printf(s, "||||");
1403 if (flags & TRACE_GRAPH_PRINT_DURATION)
1404 seq_printf(s, " | | ");
1405 seq_printf(s, " | | | |\n");
1406}
1407
1408void print_graph_headers(struct seq_file *s)
1409{
1410 print_graph_headers_flags(s, tracer_flags.val);
1411}
1412
1413void print_graph_headers_flags(struct seq_file *s, u32 flags)
1414{
1415 struct trace_iterator *iter = s->private;
1416
1417 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
1418 return;
1419
1420 if (trace_flags & TRACE_ITER_LATENCY_FMT) {
1421 /* print nothing if the buffers are empty */
1422 if (trace_empty(iter))
1423 return;
1424
1425 print_trace_header(s, iter);
1426 }
1427
1428 __print_graph_headers_flags(s, flags);
1429}
1430
1431void graph_trace_open(struct trace_iterator *iter)
1432{
1433 /* pid and depth on the last trace processed */
1434 struct fgraph_data *data;
1435 int cpu;
1436
1437 iter->private = NULL;
1438
1439 data = kzalloc(sizeof(*data), GFP_KERNEL);
1440 if (!data)
1441 goto out_err;
1442
1443 data->cpu_data = alloc_percpu(struct fgraph_cpu_data);
1444 if (!data->cpu_data)
1445 goto out_err_free;
1446
1447 for_each_possible_cpu(cpu) {
1448 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
1449 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
1450 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
1451 int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1452
1453 *pid = -1;
1454 *depth = 0;
1455 *ignore = 0;
1456 *depth_irq = -1;
1457 }
1458
1459 iter->private = data;
1460
1461 return;
1462
1463 out_err_free:
1464 kfree(data);
1465 out_err:
1466 pr_warning("function graph tracer: not enough memory\n");
1467}
1468
1469void graph_trace_close(struct trace_iterator *iter)
1470{
1471 struct fgraph_data *data = iter->private;
1472
1473 if (data) {
1474 free_percpu(data->cpu_data);
1475 kfree(data);
1476 }
1477}
1478
1479static int
1480func_graph_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1481{
1482 if (bit == TRACE_GRAPH_PRINT_IRQS)
1483 ftrace_graph_skip_irqs = !set;
1484
1485 return 0;
1486}
1487
1488static struct trace_event_functions graph_functions = {
1489 .trace = print_graph_function_event,
1490};
1491
1492static struct trace_event graph_trace_entry_event = {
1493 .type = TRACE_GRAPH_ENT,
1494 .funcs = &graph_functions,
1495};
1496
1497static struct trace_event graph_trace_ret_event = {
1498 .type = TRACE_GRAPH_RET,
1499 .funcs = &graph_functions
1500};
1501
1502static struct tracer graph_trace __tracer_data = {
1503 .name = "function_graph",
1504 .open = graph_trace_open,
1505 .pipe_open = graph_trace_open,
1506 .close = graph_trace_close,
1507 .pipe_close = graph_trace_close,
1508 .wait_pipe = poll_wait_pipe,
1509 .init = graph_trace_init,
1510 .reset = graph_trace_reset,
1511 .print_line = print_graph_function,
1512 .print_header = print_graph_headers,
1513 .flags = &tracer_flags,
1514 .set_flag = func_graph_set_flag,
1515#ifdef CONFIG_FTRACE_SELFTEST
1516 .selftest = trace_selftest_startup_function_graph,
1517#endif
1518};
1519
1520
1521static ssize_t
1522graph_depth_write(struct file *filp, const char __user *ubuf, size_t cnt,
1523 loff_t *ppos)
1524{
1525 unsigned long val;
1526 int ret;
1527
1528 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1529 if (ret)
1530 return ret;
1531
1532 max_depth = val;
1533
1534 *ppos += cnt;
1535
1536 return cnt;
1537}
1538
1539static ssize_t
1540graph_depth_read(struct file *filp, char __user *ubuf, size_t cnt,
1541 loff_t *ppos)
1542{
1543 char buf[15]; /* More than enough to hold UINT_MAX + "\n"*/
1544 int n;
1545
1546 n = sprintf(buf, "%d\n", max_depth);
1547
1548 return simple_read_from_buffer(ubuf, cnt, ppos, buf, n);
1549}
1550
1551static const struct file_operations graph_depth_fops = {
1552 .open = tracing_open_generic,
1553 .write = graph_depth_write,
1554 .read = graph_depth_read,
1555 .llseek = generic_file_llseek,
1556};
1557
1558static __init int init_graph_debugfs(void)
1559{
1560 struct dentry *d_tracer;
1561
1562 d_tracer = tracing_init_dentry();
1563 if (!d_tracer)
1564 return 0;
1565
1566 trace_create_file("max_graph_depth", 0644, d_tracer,
1567 NULL, &graph_depth_fops);
1568
1569 return 0;
1570}
1571fs_initcall(init_graph_debugfs);
1572
1573static __init int init_graph_trace(void)
1574{
1575 max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);
1576
1577 if (!register_ftrace_event(&graph_trace_entry_event)) {
1578 pr_warning("Warning: could not register graph trace events\n");
1579 return 1;
1580 }
1581
1582 if (!register_ftrace_event(&graph_trace_ret_event)) {
1583 pr_warning("Warning: could not register graph trace events\n");
1584 return 1;
1585 }
1586
1587 return register_tracer(&graph_trace);
1588}
1589
1590core_initcall(init_graph_trace);