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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
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);
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 union {
35 struct ftrace_graph_ent_entry ent;
36 struct fgraph_retaddr_ent_entry rent;
37 } ent;
38 struct ftrace_graph_ret_entry ret;
39 int failed;
40 int cpu;
41};
42
43#define TRACE_GRAPH_INDENT 2
44
45unsigned int fgraph_max_depth;
46
47static struct tracer_opt trace_opts[] = {
48 /* Display overruns? (for self-debug purpose) */
49 { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
50 /* Display CPU ? */
51 { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
52 /* Display Overhead ? */
53 { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
54 /* Display proc name/pid */
55 { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
56 /* Display duration of execution */
57 { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
58 /* Display absolute time of an entry */
59 { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
60 /* Display interrupts */
61 { TRACER_OPT(funcgraph-irqs, TRACE_GRAPH_PRINT_IRQS) },
62 /* Display function name after trailing } */
63 { TRACER_OPT(funcgraph-tail, TRACE_GRAPH_PRINT_TAIL) },
64#ifdef CONFIG_FUNCTION_GRAPH_RETVAL
65 /* Display function return value ? */
66 { TRACER_OPT(funcgraph-retval, TRACE_GRAPH_PRINT_RETVAL) },
67 /* Display function return value in hexadecimal format ? */
68 { TRACER_OPT(funcgraph-retval-hex, TRACE_GRAPH_PRINT_RETVAL_HEX) },
69#endif
70#ifdef CONFIG_FUNCTION_GRAPH_RETADDR
71 /* Display function return address ? */
72 { TRACER_OPT(funcgraph-retaddr, TRACE_GRAPH_PRINT_RETADDR) },
73#endif
74 /* Include sleep time (scheduled out) between entry and return */
75 { TRACER_OPT(sleep-time, TRACE_GRAPH_SLEEP_TIME) },
76
77#ifdef CONFIG_FUNCTION_PROFILER
78 /* Include time within nested functions */
79 { TRACER_OPT(graph-time, TRACE_GRAPH_GRAPH_TIME) },
80#endif
81
82 { } /* Empty entry */
83};
84
85static struct tracer_flags tracer_flags = {
86 /* Don't display overruns, proc, or tail by default */
87 .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
88 TRACE_GRAPH_PRINT_DURATION | TRACE_GRAPH_PRINT_IRQS |
89 TRACE_GRAPH_SLEEP_TIME | TRACE_GRAPH_GRAPH_TIME,
90 .opts = trace_opts
91};
92
93static bool tracer_flags_is_set(u32 flags)
94{
95 return (tracer_flags.val & flags) == flags;
96}
97
98/*
99 * DURATION column is being also used to display IRQ signs,
100 * following values are used by print_graph_irq and others
101 * to fill in space into DURATION column.
102 */
103enum {
104 FLAGS_FILL_FULL = 1 << TRACE_GRAPH_PRINT_FILL_SHIFT,
105 FLAGS_FILL_START = 2 << TRACE_GRAPH_PRINT_FILL_SHIFT,
106 FLAGS_FILL_END = 3 << TRACE_GRAPH_PRINT_FILL_SHIFT,
107};
108
109static void
110print_graph_duration(struct trace_array *tr, unsigned long long duration,
111 struct trace_seq *s, u32 flags);
112
113int __trace_graph_entry(struct trace_array *tr,
114 struct ftrace_graph_ent *trace,
115 unsigned int trace_ctx)
116{
117 struct ring_buffer_event *event;
118 struct trace_buffer *buffer = tr->array_buffer.buffer;
119 struct ftrace_graph_ent_entry *entry;
120
121 event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
122 sizeof(*entry), trace_ctx);
123 if (!event)
124 return 0;
125 entry = ring_buffer_event_data(event);
126 entry->graph_ent = *trace;
127 trace_buffer_unlock_commit_nostack(buffer, event);
128
129 return 1;
130}
131
132#ifdef CONFIG_FUNCTION_GRAPH_RETADDR
133int __trace_graph_retaddr_entry(struct trace_array *tr,
134 struct ftrace_graph_ent *trace,
135 unsigned int trace_ctx,
136 unsigned long retaddr)
137{
138 struct ring_buffer_event *event;
139 struct trace_buffer *buffer = tr->array_buffer.buffer;
140 struct fgraph_retaddr_ent_entry *entry;
141
142 event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RETADDR_ENT,
143 sizeof(*entry), trace_ctx);
144 if (!event)
145 return 0;
146 entry = ring_buffer_event_data(event);
147 entry->graph_ent.func = trace->func;
148 entry->graph_ent.depth = trace->depth;
149 entry->graph_ent.retaddr = retaddr;
150 trace_buffer_unlock_commit_nostack(buffer, event);
151
152 return 1;
153}
154#else
155int __trace_graph_retaddr_entry(struct trace_array *tr,
156 struct ftrace_graph_ent *trace,
157 unsigned int trace_ctx,
158 unsigned long retaddr)
159{
160 return 1;
161}
162#endif
163
164static inline int ftrace_graph_ignore_irqs(void)
165{
166 if (!ftrace_graph_skip_irqs || trace_recursion_test(TRACE_IRQ_BIT))
167 return 0;
168
169 return in_hardirq();
170}
171
172struct fgraph_times {
173 unsigned long long calltime;
174 unsigned long long sleeptime; /* may be optional! */
175};
176
177int trace_graph_entry(struct ftrace_graph_ent *trace,
178 struct fgraph_ops *gops)
179{
180 unsigned long *task_var = fgraph_get_task_var(gops);
181 struct trace_array *tr = gops->private;
182 struct trace_array_cpu *data;
183 struct fgraph_times *ftimes;
184 unsigned long flags;
185 unsigned int trace_ctx;
186 long disabled;
187 int ret;
188 int cpu;
189
190 if (*task_var & TRACE_GRAPH_NOTRACE)
191 return 0;
192
193 /*
194 * Do not trace a function if it's filtered by set_graph_notrace.
195 * Make the index of ret stack negative to indicate that it should
196 * ignore further functions. But it needs its own ret stack entry
197 * to recover the original index in order to continue tracing after
198 * returning from the function.
199 */
200 if (ftrace_graph_notrace_addr(trace->func)) {
201 *task_var |= TRACE_GRAPH_NOTRACE;
202 /*
203 * Need to return 1 to have the return called
204 * that will clear the NOTRACE bit.
205 */
206 return 1;
207 }
208
209 if (!ftrace_trace_task(tr))
210 return 0;
211
212 if (ftrace_graph_ignore_func(gops, trace))
213 return 0;
214
215 if (ftrace_graph_ignore_irqs())
216 return 0;
217
218 if (fgraph_sleep_time) {
219 /* Only need to record the calltime */
220 ftimes = fgraph_reserve_data(gops->idx, sizeof(ftimes->calltime));
221 } else {
222 ftimes = fgraph_reserve_data(gops->idx, sizeof(*ftimes));
223 if (ftimes)
224 ftimes->sleeptime = current->ftrace_sleeptime;
225 }
226 if (!ftimes)
227 return 0;
228
229 ftimes->calltime = trace_clock_local();
230
231 /*
232 * Stop here if tracing_threshold is set. We only write function return
233 * events to the ring buffer.
234 */
235 if (tracing_thresh)
236 return 1;
237
238 local_irq_save(flags);
239 cpu = raw_smp_processor_id();
240 data = per_cpu_ptr(tr->array_buffer.data, cpu);
241 disabled = atomic_inc_return(&data->disabled);
242 if (likely(disabled == 1)) {
243 trace_ctx = tracing_gen_ctx_flags(flags);
244 if (unlikely(IS_ENABLED(CONFIG_FUNCTION_GRAPH_RETADDR) &&
245 tracer_flags_is_set(TRACE_GRAPH_PRINT_RETADDR))) {
246 unsigned long retaddr = ftrace_graph_top_ret_addr(current);
247
248 ret = __trace_graph_retaddr_entry(tr, trace, trace_ctx, retaddr);
249 } else
250 ret = __trace_graph_entry(tr, trace, trace_ctx);
251 } else {
252 ret = 0;
253 }
254
255 atomic_dec(&data->disabled);
256 local_irq_restore(flags);
257
258 return ret;
259}
260
261static void
262__trace_graph_function(struct trace_array *tr,
263 unsigned long ip, unsigned int trace_ctx)
264{
265 u64 time = trace_clock_local();
266 struct ftrace_graph_ent ent = {
267 .func = ip,
268 .depth = 0,
269 };
270 struct ftrace_graph_ret ret = {
271 .func = ip,
272 .depth = 0,
273 .calltime = time,
274 .rettime = time,
275 };
276
277 __trace_graph_entry(tr, &ent, trace_ctx);
278 __trace_graph_return(tr, &ret, trace_ctx);
279}
280
281void
282trace_graph_function(struct trace_array *tr,
283 unsigned long ip, unsigned long parent_ip,
284 unsigned int trace_ctx)
285{
286 __trace_graph_function(tr, ip, trace_ctx);
287}
288
289void __trace_graph_return(struct trace_array *tr,
290 struct ftrace_graph_ret *trace,
291 unsigned int trace_ctx)
292{
293 struct ring_buffer_event *event;
294 struct trace_buffer *buffer = tr->array_buffer.buffer;
295 struct ftrace_graph_ret_entry *entry;
296
297 event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
298 sizeof(*entry), trace_ctx);
299 if (!event)
300 return;
301 entry = ring_buffer_event_data(event);
302 entry->ret = *trace;
303 trace_buffer_unlock_commit_nostack(buffer, event);
304}
305
306static void handle_nosleeptime(struct ftrace_graph_ret *trace,
307 struct fgraph_times *ftimes,
308 int size)
309{
310 if (fgraph_sleep_time || size < sizeof(*ftimes))
311 return;
312
313 ftimes->calltime += current->ftrace_sleeptime - ftimes->sleeptime;
314}
315
316void trace_graph_return(struct ftrace_graph_ret *trace,
317 struct fgraph_ops *gops)
318{
319 unsigned long *task_var = fgraph_get_task_var(gops);
320 struct trace_array *tr = gops->private;
321 struct trace_array_cpu *data;
322 struct fgraph_times *ftimes;
323 unsigned long flags;
324 unsigned int trace_ctx;
325 long disabled;
326 int size;
327 int cpu;
328
329 ftrace_graph_addr_finish(gops, trace);
330
331 if (*task_var & TRACE_GRAPH_NOTRACE) {
332 *task_var &= ~TRACE_GRAPH_NOTRACE;
333 return;
334 }
335
336 ftimes = fgraph_retrieve_data(gops->idx, &size);
337 if (!ftimes)
338 return;
339
340 handle_nosleeptime(trace, ftimes, size);
341
342 trace->calltime = ftimes->calltime;
343
344 local_irq_save(flags);
345 cpu = raw_smp_processor_id();
346 data = per_cpu_ptr(tr->array_buffer.data, cpu);
347 disabled = atomic_inc_return(&data->disabled);
348 if (likely(disabled == 1)) {
349 trace_ctx = tracing_gen_ctx_flags(flags);
350 __trace_graph_return(tr, trace, trace_ctx);
351 }
352 atomic_dec(&data->disabled);
353 local_irq_restore(flags);
354}
355
356static void trace_graph_thresh_return(struct ftrace_graph_ret *trace,
357 struct fgraph_ops *gops)
358{
359 struct fgraph_times *ftimes;
360 int size;
361
362 ftrace_graph_addr_finish(gops, trace);
363
364 if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
365 trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
366 return;
367 }
368
369 ftimes = fgraph_retrieve_data(gops->idx, &size);
370 if (!ftimes)
371 return;
372
373 handle_nosleeptime(trace, ftimes, size);
374
375 trace->calltime = ftimes->calltime;
376
377 if (tracing_thresh &&
378 (trace->rettime - ftimes->calltime < tracing_thresh))
379 return;
380 else
381 trace_graph_return(trace, gops);
382}
383
384static struct fgraph_ops funcgraph_ops = {
385 .entryfunc = &trace_graph_entry,
386 .retfunc = &trace_graph_return,
387};
388
389int allocate_fgraph_ops(struct trace_array *tr, struct ftrace_ops *ops)
390{
391 struct fgraph_ops *gops;
392
393 gops = kzalloc(sizeof(*gops), GFP_KERNEL);
394 if (!gops)
395 return -ENOMEM;
396
397 gops->entryfunc = &trace_graph_entry;
398 gops->retfunc = &trace_graph_return;
399
400 tr->gops = gops;
401 gops->private = tr;
402
403 fgraph_init_ops(&gops->ops, ops);
404
405 return 0;
406}
407
408void free_fgraph_ops(struct trace_array *tr)
409{
410 kfree(tr->gops);
411}
412
413__init void init_array_fgraph_ops(struct trace_array *tr, struct ftrace_ops *ops)
414{
415 tr->gops = &funcgraph_ops;
416 funcgraph_ops.private = tr;
417 fgraph_init_ops(&tr->gops->ops, ops);
418}
419
420static int graph_trace_init(struct trace_array *tr)
421{
422 int ret;
423
424 tr->gops->entryfunc = trace_graph_entry;
425
426 if (tracing_thresh)
427 tr->gops->retfunc = trace_graph_thresh_return;
428 else
429 tr->gops->retfunc = trace_graph_return;
430
431 /* Make gops functions are visible before we start tracing */
432 smp_mb();
433
434 ret = register_ftrace_graph(tr->gops);
435 if (ret)
436 return ret;
437 tracing_start_cmdline_record();
438
439 return 0;
440}
441
442static void graph_trace_reset(struct trace_array *tr)
443{
444 tracing_stop_cmdline_record();
445 unregister_ftrace_graph(tr->gops);
446}
447
448static int graph_trace_update_thresh(struct trace_array *tr)
449{
450 graph_trace_reset(tr);
451 return graph_trace_init(tr);
452}
453
454static int max_bytes_for_cpu;
455
456static void print_graph_cpu(struct trace_seq *s, int cpu)
457{
458 /*
459 * Start with a space character - to make it stand out
460 * to the right a bit when trace output is pasted into
461 * email:
462 */
463 trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
464}
465
466#define TRACE_GRAPH_PROCINFO_LENGTH 14
467
468static void print_graph_proc(struct trace_seq *s, pid_t pid)
469{
470 char comm[TASK_COMM_LEN];
471 /* sign + log10(MAX_INT) + '\0' */
472 char pid_str[11];
473 int spaces = 0;
474 int len;
475 int i;
476
477 trace_find_cmdline(pid, comm);
478 comm[7] = '\0';
479 sprintf(pid_str, "%d", pid);
480
481 /* 1 stands for the "-" character */
482 len = strlen(comm) + strlen(pid_str) + 1;
483
484 if (len < TRACE_GRAPH_PROCINFO_LENGTH)
485 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
486
487 /* First spaces to align center */
488 for (i = 0; i < spaces / 2; i++)
489 trace_seq_putc(s, ' ');
490
491 trace_seq_printf(s, "%s-%s", comm, pid_str);
492
493 /* Last spaces to align center */
494 for (i = 0; i < spaces - (spaces / 2); i++)
495 trace_seq_putc(s, ' ');
496}
497
498
499static void print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
500{
501 trace_seq_putc(s, ' ');
502 trace_print_lat_fmt(s, entry);
503 trace_seq_puts(s, " | ");
504}
505
506/* If the pid changed since the last trace, output this event */
507static void
508verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
509{
510 pid_t prev_pid;
511 pid_t *last_pid;
512
513 if (!data)
514 return;
515
516 last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
517
518 if (*last_pid == pid)
519 return;
520
521 prev_pid = *last_pid;
522 *last_pid = pid;
523
524 if (prev_pid == -1)
525 return;
526/*
527 * Context-switch trace line:
528
529 ------------------------------------------
530 | 1) migration/0--1 => sshd-1755
531 ------------------------------------------
532
533 */
534 trace_seq_puts(s, " ------------------------------------------\n");
535 print_graph_cpu(s, cpu);
536 print_graph_proc(s, prev_pid);
537 trace_seq_puts(s, " => ");
538 print_graph_proc(s, pid);
539 trace_seq_puts(s, "\n ------------------------------------------\n\n");
540}
541
542static struct ftrace_graph_ret_entry *
543get_return_for_leaf(struct trace_iterator *iter,
544 struct ftrace_graph_ent_entry *curr)
545{
546 struct fgraph_data *data = iter->private;
547 struct ring_buffer_iter *ring_iter = NULL;
548 struct ring_buffer_event *event;
549 struct ftrace_graph_ret_entry *next;
550
551 /*
552 * If the previous output failed to write to the seq buffer,
553 * then we just reuse the data from before.
554 */
555 if (data && data->failed) {
556 curr = &data->ent.ent;
557 next = &data->ret;
558 } else {
559
560 ring_iter = trace_buffer_iter(iter, iter->cpu);
561
562 /* First peek to compare current entry and the next one */
563 if (ring_iter)
564 event = ring_buffer_iter_peek(ring_iter, NULL);
565 else {
566 /*
567 * We need to consume the current entry to see
568 * the next one.
569 */
570 ring_buffer_consume(iter->array_buffer->buffer, iter->cpu,
571 NULL, NULL);
572 event = ring_buffer_peek(iter->array_buffer->buffer, iter->cpu,
573 NULL, NULL);
574 }
575
576 if (!event)
577 return NULL;
578
579 next = ring_buffer_event_data(event);
580
581 if (data) {
582 /*
583 * Save current and next entries for later reference
584 * if the output fails.
585 */
586 if (unlikely(curr->ent.type == TRACE_GRAPH_RETADDR_ENT))
587 data->ent.rent = *(struct fgraph_retaddr_ent_entry *)curr;
588 else
589 data->ent.ent = *curr;
590 /*
591 * If the next event is not a return type, then
592 * we only care about what type it is. Otherwise we can
593 * safely copy the entire event.
594 */
595 if (next->ent.type == TRACE_GRAPH_RET)
596 data->ret = *next;
597 else
598 data->ret.ent.type = next->ent.type;
599 }
600 }
601
602 if (next->ent.type != TRACE_GRAPH_RET)
603 return NULL;
604
605 if (curr->ent.pid != next->ent.pid ||
606 curr->graph_ent.func != next->ret.func)
607 return NULL;
608
609 /* this is a leaf, now advance the iterator */
610 if (ring_iter)
611 ring_buffer_iter_advance(ring_iter);
612
613 return next;
614}
615
616static void print_graph_abs_time(u64 t, struct trace_seq *s)
617{
618 unsigned long usecs_rem;
619
620 usecs_rem = do_div(t, NSEC_PER_SEC);
621 usecs_rem /= 1000;
622
623 trace_seq_printf(s, "%5lu.%06lu | ",
624 (unsigned long)t, usecs_rem);
625}
626
627static void
628print_graph_rel_time(struct trace_iterator *iter, struct trace_seq *s)
629{
630 unsigned long long usecs;
631
632 usecs = iter->ts - iter->array_buffer->time_start;
633 do_div(usecs, NSEC_PER_USEC);
634
635 trace_seq_printf(s, "%9llu us | ", usecs);
636}
637
638static void
639print_graph_irq(struct trace_iterator *iter, unsigned long addr,
640 enum trace_type type, int cpu, pid_t pid, u32 flags)
641{
642 struct trace_array *tr = iter->tr;
643 struct trace_seq *s = &iter->seq;
644 struct trace_entry *ent = iter->ent;
645
646 addr += iter->tr->text_delta;
647
648 if (addr < (unsigned long)__irqentry_text_start ||
649 addr >= (unsigned long)__irqentry_text_end)
650 return;
651
652 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
653 /* Absolute time */
654 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
655 print_graph_abs_time(iter->ts, s);
656
657 /* Relative time */
658 if (flags & TRACE_GRAPH_PRINT_REL_TIME)
659 print_graph_rel_time(iter, s);
660
661 /* Cpu */
662 if (flags & TRACE_GRAPH_PRINT_CPU)
663 print_graph_cpu(s, cpu);
664
665 /* Proc */
666 if (flags & TRACE_GRAPH_PRINT_PROC) {
667 print_graph_proc(s, pid);
668 trace_seq_puts(s, " | ");
669 }
670
671 /* Latency format */
672 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
673 print_graph_lat_fmt(s, ent);
674 }
675
676 /* No overhead */
677 print_graph_duration(tr, 0, s, flags | FLAGS_FILL_START);
678
679 if (type == TRACE_GRAPH_ENT)
680 trace_seq_puts(s, "==========>");
681 else
682 trace_seq_puts(s, "<==========");
683
684 print_graph_duration(tr, 0, s, flags | FLAGS_FILL_END);
685 trace_seq_putc(s, '\n');
686}
687
688void
689trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
690{
691 unsigned long nsecs_rem = do_div(duration, 1000);
692 /* log10(ULONG_MAX) + '\0' */
693 char usecs_str[21];
694 char nsecs_str[5];
695 int len;
696 int i;
697
698 sprintf(usecs_str, "%lu", (unsigned long) duration);
699
700 /* Print msecs */
701 trace_seq_printf(s, "%s", usecs_str);
702
703 len = strlen(usecs_str);
704
705 /* Print nsecs (we don't want to exceed 7 numbers) */
706 if (len < 7) {
707 size_t slen = min_t(size_t, sizeof(nsecs_str), 8UL - len);
708
709 snprintf(nsecs_str, slen, "%03lu", nsecs_rem);
710 trace_seq_printf(s, ".%s", nsecs_str);
711 len += strlen(nsecs_str) + 1;
712 }
713
714 trace_seq_puts(s, " us ");
715
716 /* Print remaining spaces to fit the row's width */
717 for (i = len; i < 8; i++)
718 trace_seq_putc(s, ' ');
719}
720
721static void
722print_graph_duration(struct trace_array *tr, unsigned long long duration,
723 struct trace_seq *s, u32 flags)
724{
725 if (!(flags & TRACE_GRAPH_PRINT_DURATION) ||
726 !(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
727 return;
728
729 /* No real adata, just filling the column with spaces */
730 switch (flags & TRACE_GRAPH_PRINT_FILL_MASK) {
731 case FLAGS_FILL_FULL:
732 trace_seq_puts(s, " | ");
733 return;
734 case FLAGS_FILL_START:
735 trace_seq_puts(s, " ");
736 return;
737 case FLAGS_FILL_END:
738 trace_seq_puts(s, " |");
739 return;
740 }
741
742 /* Signal a overhead of time execution to the output */
743 if (flags & TRACE_GRAPH_PRINT_OVERHEAD)
744 trace_seq_printf(s, "%c ", trace_find_mark(duration));
745 else
746 trace_seq_puts(s, " ");
747
748 trace_print_graph_duration(duration, s);
749 trace_seq_puts(s, "| ");
750}
751
752#ifdef CONFIG_FUNCTION_GRAPH_RETVAL
753#define __TRACE_GRAPH_PRINT_RETVAL TRACE_GRAPH_PRINT_RETVAL
754#else
755#define __TRACE_GRAPH_PRINT_RETVAL 0
756#endif
757
758#ifdef CONFIG_FUNCTION_GRAPH_RETADDR
759#define __TRACE_GRAPH_PRINT_RETADDR TRACE_GRAPH_PRINT_RETADDR
760static void print_graph_retaddr(struct trace_seq *s, struct fgraph_retaddr_ent_entry *entry,
761 u32 trace_flags, bool comment)
762{
763 if (comment)
764 trace_seq_puts(s, " /*");
765
766 trace_seq_puts(s, " <-");
767 seq_print_ip_sym(s, entry->graph_ent.retaddr, trace_flags | TRACE_ITER_SYM_OFFSET);
768
769 if (comment)
770 trace_seq_puts(s, " */");
771}
772#else
773#define __TRACE_GRAPH_PRINT_RETADDR 0
774#define print_graph_retaddr(_seq, _entry, _tflags, _comment) do { } while (0)
775#endif
776
777#if defined(CONFIG_FUNCTION_GRAPH_RETVAL) || defined(CONFIG_FUNCTION_GRAPH_RETADDR)
778
779static void print_graph_retval(struct trace_seq *s, struct ftrace_graph_ent_entry *entry,
780 struct ftrace_graph_ret *graph_ret, void *func,
781 u32 opt_flags, u32 trace_flags)
782{
783 unsigned long err_code = 0;
784 unsigned long retval = 0;
785 bool print_retaddr = false;
786 bool print_retval = false;
787 bool hex_format = !!(opt_flags & TRACE_GRAPH_PRINT_RETVAL_HEX);
788
789#ifdef CONFIG_FUNCTION_GRAPH_RETVAL
790 retval = graph_ret->retval;
791 print_retval = !!(opt_flags & TRACE_GRAPH_PRINT_RETVAL);
792#endif
793
794#ifdef CONFIG_FUNCTION_GRAPH_RETADDR
795 print_retaddr = !!(opt_flags & TRACE_GRAPH_PRINT_RETADDR);
796#endif
797
798 if (print_retval && retval && !hex_format) {
799 /* Check if the return value matches the negative format */
800 if (IS_ENABLED(CONFIG_64BIT) && (retval & BIT(31)) &&
801 (((u64)retval) >> 32) == 0) {
802 err_code = sign_extend64(retval, 31);
803 } else {
804 err_code = retval;
805 }
806
807 if (!IS_ERR_VALUE(err_code))
808 err_code = 0;
809 }
810
811 if (entry) {
812 if (entry->ent.type != TRACE_GRAPH_RETADDR_ENT)
813 print_retaddr = false;
814
815 trace_seq_printf(s, "%ps();", func);
816 if (print_retval || print_retaddr)
817 trace_seq_puts(s, " /*");
818 else
819 trace_seq_putc(s, '\n');
820 } else {
821 print_retaddr = false;
822 trace_seq_printf(s, "} /* %ps", func);
823 }
824
825 if (print_retaddr)
826 print_graph_retaddr(s, (struct fgraph_retaddr_ent_entry *)entry,
827 trace_flags, false);
828
829 if (print_retval) {
830 if (hex_format || (err_code == 0))
831 trace_seq_printf(s, " ret=0x%lx", retval);
832 else
833 trace_seq_printf(s, " ret=%ld", err_code);
834 }
835
836 if (!entry || print_retval || print_retaddr)
837 trace_seq_puts(s, " */\n");
838}
839
840#else
841
842#define print_graph_retval(_seq, _ent, _ret, _func, _opt_flags, _trace_flags) do {} while (0)
843
844#endif
845
846/* Case of a leaf function on its call entry */
847static enum print_line_t
848print_graph_entry_leaf(struct trace_iterator *iter,
849 struct ftrace_graph_ent_entry *entry,
850 struct ftrace_graph_ret_entry *ret_entry,
851 struct trace_seq *s, u32 flags)
852{
853 struct fgraph_data *data = iter->private;
854 struct trace_array *tr = iter->tr;
855 struct ftrace_graph_ret *graph_ret;
856 struct ftrace_graph_ent *call;
857 unsigned long long duration;
858 unsigned long func;
859 int cpu = iter->cpu;
860 int i;
861
862 graph_ret = &ret_entry->ret;
863 call = &entry->graph_ent;
864 duration = graph_ret->rettime - graph_ret->calltime;
865
866 func = call->func + iter->tr->text_delta;
867
868 if (data) {
869 struct fgraph_cpu_data *cpu_data;
870
871 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
872
873 /*
874 * Comments display at + 1 to depth. Since
875 * this is a leaf function, keep the comments
876 * equal to this depth.
877 */
878 cpu_data->depth = call->depth - 1;
879
880 /* No need to keep this function around for this depth */
881 if (call->depth < FTRACE_RETFUNC_DEPTH &&
882 !WARN_ON_ONCE(call->depth < 0))
883 cpu_data->enter_funcs[call->depth] = 0;
884 }
885
886 /* Overhead and duration */
887 print_graph_duration(tr, duration, s, flags);
888
889 /* Function */
890 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
891 trace_seq_putc(s, ' ');
892
893 /*
894 * Write out the function return value or return address
895 */
896 if (flags & (__TRACE_GRAPH_PRINT_RETVAL | __TRACE_GRAPH_PRINT_RETADDR)) {
897 print_graph_retval(s, entry, graph_ret,
898 (void *)graph_ret->func + iter->tr->text_delta,
899 flags, tr->trace_flags);
900 } else {
901 trace_seq_printf(s, "%ps();\n", (void *)func);
902 }
903
904 print_graph_irq(iter, graph_ret->func, TRACE_GRAPH_RET,
905 cpu, iter->ent->pid, flags);
906
907 return trace_handle_return(s);
908}
909
910static enum print_line_t
911print_graph_entry_nested(struct trace_iterator *iter,
912 struct ftrace_graph_ent_entry *entry,
913 struct trace_seq *s, int cpu, u32 flags)
914{
915 struct ftrace_graph_ent *call = &entry->graph_ent;
916 struct fgraph_data *data = iter->private;
917 struct trace_array *tr = iter->tr;
918 unsigned long func;
919 int i;
920
921 if (data) {
922 struct fgraph_cpu_data *cpu_data;
923 int cpu = iter->cpu;
924
925 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
926 cpu_data->depth = call->depth;
927
928 /* Save this function pointer to see if the exit matches */
929 if (call->depth < FTRACE_RETFUNC_DEPTH &&
930 !WARN_ON_ONCE(call->depth < 0))
931 cpu_data->enter_funcs[call->depth] = call->func;
932 }
933
934 /* No time */
935 print_graph_duration(tr, 0, s, flags | FLAGS_FILL_FULL);
936
937 /* Function */
938 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
939 trace_seq_putc(s, ' ');
940
941 func = call->func + iter->tr->text_delta;
942
943 trace_seq_printf(s, "%ps() {", (void *)func);
944 if (flags & __TRACE_GRAPH_PRINT_RETADDR &&
945 entry->ent.type == TRACE_GRAPH_RETADDR_ENT)
946 print_graph_retaddr(s, (struct fgraph_retaddr_ent_entry *)entry,
947 tr->trace_flags, true);
948 trace_seq_putc(s, '\n');
949
950 if (trace_seq_has_overflowed(s))
951 return TRACE_TYPE_PARTIAL_LINE;
952
953 /*
954 * we already consumed the current entry to check the next one
955 * and see if this is a leaf.
956 */
957 return TRACE_TYPE_NO_CONSUME;
958}
959
960static void
961print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
962 int type, unsigned long addr, u32 flags)
963{
964 struct fgraph_data *data = iter->private;
965 struct trace_entry *ent = iter->ent;
966 struct trace_array *tr = iter->tr;
967 int cpu = iter->cpu;
968
969 /* Pid */
970 verif_pid(s, ent->pid, cpu, data);
971
972 if (type)
973 /* Interrupt */
974 print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
975
976 if (!(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
977 return;
978
979 /* Absolute time */
980 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
981 print_graph_abs_time(iter->ts, s);
982
983 /* Relative time */
984 if (flags & TRACE_GRAPH_PRINT_REL_TIME)
985 print_graph_rel_time(iter, s);
986
987 /* Cpu */
988 if (flags & TRACE_GRAPH_PRINT_CPU)
989 print_graph_cpu(s, cpu);
990
991 /* Proc */
992 if (flags & TRACE_GRAPH_PRINT_PROC) {
993 print_graph_proc(s, ent->pid);
994 trace_seq_puts(s, " | ");
995 }
996
997 /* Latency format */
998 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
999 print_graph_lat_fmt(s, ent);
1000
1001 return;
1002}
1003
1004/*
1005 * Entry check for irq code
1006 *
1007 * returns 1 if
1008 * - we are inside irq code
1009 * - we just entered irq code
1010 *
1011 * returns 0 if
1012 * - funcgraph-interrupts option is set
1013 * - we are not inside irq code
1014 */
1015static int
1016check_irq_entry(struct trace_iterator *iter, u32 flags,
1017 unsigned long addr, int depth)
1018{
1019 int cpu = iter->cpu;
1020 int *depth_irq;
1021 struct fgraph_data *data = iter->private;
1022
1023 addr += iter->tr->text_delta;
1024
1025 /*
1026 * If we are either displaying irqs, or we got called as
1027 * a graph event and private data does not exist,
1028 * then we bypass the irq check.
1029 */
1030 if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
1031 (!data))
1032 return 0;
1033
1034 depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1035
1036 /*
1037 * We are inside the irq code
1038 */
1039 if (*depth_irq >= 0)
1040 return 1;
1041
1042 if ((addr < (unsigned long)__irqentry_text_start) ||
1043 (addr >= (unsigned long)__irqentry_text_end))
1044 return 0;
1045
1046 /*
1047 * We are entering irq code.
1048 */
1049 *depth_irq = depth;
1050 return 1;
1051}
1052
1053/*
1054 * Return check for irq code
1055 *
1056 * returns 1 if
1057 * - we are inside irq code
1058 * - we just left irq code
1059 *
1060 * returns 0 if
1061 * - funcgraph-interrupts option is set
1062 * - we are not inside irq code
1063 */
1064static int
1065check_irq_return(struct trace_iterator *iter, u32 flags, int depth)
1066{
1067 int cpu = iter->cpu;
1068 int *depth_irq;
1069 struct fgraph_data *data = iter->private;
1070
1071 /*
1072 * If we are either displaying irqs, or we got called as
1073 * a graph event and private data does not exist,
1074 * then we bypass the irq check.
1075 */
1076 if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
1077 (!data))
1078 return 0;
1079
1080 depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1081
1082 /*
1083 * We are not inside the irq code.
1084 */
1085 if (*depth_irq == -1)
1086 return 0;
1087
1088 /*
1089 * We are inside the irq code, and this is returning entry.
1090 * Let's not trace it and clear the entry depth, since
1091 * we are out of irq code.
1092 *
1093 * This condition ensures that we 'leave the irq code' once
1094 * we are out of the entry depth. Thus protecting us from
1095 * the RETURN entry loss.
1096 */
1097 if (*depth_irq >= depth) {
1098 *depth_irq = -1;
1099 return 1;
1100 }
1101
1102 /*
1103 * We are inside the irq code, and this is not the entry.
1104 */
1105 return 1;
1106}
1107
1108static enum print_line_t
1109print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
1110 struct trace_iterator *iter, u32 flags)
1111{
1112 struct fgraph_data *data = iter->private;
1113 struct ftrace_graph_ent *call = &field->graph_ent;
1114 struct ftrace_graph_ret_entry *leaf_ret;
1115 static enum print_line_t ret;
1116 int cpu = iter->cpu;
1117
1118 if (check_irq_entry(iter, flags, call->func, call->depth))
1119 return TRACE_TYPE_HANDLED;
1120
1121 print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags);
1122
1123 leaf_ret = get_return_for_leaf(iter, field);
1124 if (leaf_ret)
1125 ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags);
1126 else
1127 ret = print_graph_entry_nested(iter, field, s, cpu, flags);
1128
1129 if (data) {
1130 /*
1131 * If we failed to write our output, then we need to make
1132 * note of it. Because we already consumed our entry.
1133 */
1134 if (s->full) {
1135 data->failed = 1;
1136 data->cpu = cpu;
1137 } else
1138 data->failed = 0;
1139 }
1140
1141 return ret;
1142}
1143
1144static enum print_line_t
1145print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
1146 struct trace_entry *ent, struct trace_iterator *iter,
1147 u32 flags)
1148{
1149 unsigned long long duration = trace->rettime - trace->calltime;
1150 struct fgraph_data *data = iter->private;
1151 struct trace_array *tr = iter->tr;
1152 unsigned long func;
1153 pid_t pid = ent->pid;
1154 int cpu = iter->cpu;
1155 int func_match = 1;
1156 int i;
1157
1158 func = trace->func + iter->tr->text_delta;
1159
1160 if (check_irq_return(iter, flags, trace->depth))
1161 return TRACE_TYPE_HANDLED;
1162
1163 if (data) {
1164 struct fgraph_cpu_data *cpu_data;
1165 int cpu = iter->cpu;
1166
1167 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
1168
1169 /*
1170 * Comments display at + 1 to depth. This is the
1171 * return from a function, we now want the comments
1172 * to display at the same level of the bracket.
1173 */
1174 cpu_data->depth = trace->depth - 1;
1175
1176 if (trace->depth < FTRACE_RETFUNC_DEPTH &&
1177 !WARN_ON_ONCE(trace->depth < 0)) {
1178 if (cpu_data->enter_funcs[trace->depth] != trace->func)
1179 func_match = 0;
1180 cpu_data->enter_funcs[trace->depth] = 0;
1181 }
1182 }
1183
1184 print_graph_prologue(iter, s, 0, 0, flags);
1185
1186 /* Overhead and duration */
1187 print_graph_duration(tr, duration, s, flags);
1188
1189 /* Closing brace */
1190 for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++)
1191 trace_seq_putc(s, ' ');
1192
1193 /*
1194 * Always write out the function name and its return value if the
1195 * funcgraph-retval option is enabled.
1196 */
1197 if (flags & __TRACE_GRAPH_PRINT_RETVAL) {
1198 print_graph_retval(s, NULL, trace, (void *)func, flags, tr->trace_flags);
1199 } else {
1200 /*
1201 * If the return function does not have a matching entry,
1202 * then the entry was lost. Instead of just printing
1203 * the '}' and letting the user guess what function this
1204 * belongs to, write out the function name. Always do
1205 * that if the funcgraph-tail option is enabled.
1206 */
1207 if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL))
1208 trace_seq_puts(s, "}\n");
1209 else
1210 trace_seq_printf(s, "} /* %ps */\n", (void *)func);
1211 }
1212
1213 /* Overrun */
1214 if (flags & TRACE_GRAPH_PRINT_OVERRUN)
1215 trace_seq_printf(s, " (Overruns: %u)\n",
1216 trace->overrun);
1217
1218 print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
1219 cpu, pid, flags);
1220
1221 return trace_handle_return(s);
1222}
1223
1224static enum print_line_t
1225print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
1226 struct trace_iterator *iter, u32 flags)
1227{
1228 struct trace_array *tr = iter->tr;
1229 unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
1230 struct fgraph_data *data = iter->private;
1231 struct trace_event *event;
1232 int depth = 0;
1233 int ret;
1234 int i;
1235
1236 if (data)
1237 depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
1238
1239 print_graph_prologue(iter, s, 0, 0, flags);
1240
1241 /* No time */
1242 print_graph_duration(tr, 0, s, flags | FLAGS_FILL_FULL);
1243
1244 /* Indentation */
1245 if (depth > 0)
1246 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++)
1247 trace_seq_putc(s, ' ');
1248
1249 /* The comment */
1250 trace_seq_puts(s, "/* ");
1251
1252 switch (iter->ent->type) {
1253 case TRACE_BPUTS:
1254 ret = trace_print_bputs_msg_only(iter);
1255 if (ret != TRACE_TYPE_HANDLED)
1256 return ret;
1257 break;
1258 case TRACE_BPRINT:
1259 ret = trace_print_bprintk_msg_only(iter);
1260 if (ret != TRACE_TYPE_HANDLED)
1261 return ret;
1262 break;
1263 case TRACE_PRINT:
1264 ret = trace_print_printk_msg_only(iter);
1265 if (ret != TRACE_TYPE_HANDLED)
1266 return ret;
1267 break;
1268 default:
1269 event = ftrace_find_event(ent->type);
1270 if (!event)
1271 return TRACE_TYPE_UNHANDLED;
1272
1273 ret = event->funcs->trace(iter, sym_flags, event);
1274 if (ret != TRACE_TYPE_HANDLED)
1275 return ret;
1276 }
1277
1278 if (trace_seq_has_overflowed(s))
1279 goto out;
1280
1281 /* Strip ending newline */
1282 if (s->buffer[s->seq.len - 1] == '\n') {
1283 s->buffer[s->seq.len - 1] = '\0';
1284 s->seq.len--;
1285 }
1286
1287 trace_seq_puts(s, " */\n");
1288 out:
1289 return trace_handle_return(s);
1290}
1291
1292
1293enum print_line_t
1294print_graph_function_flags(struct trace_iterator *iter, u32 flags)
1295{
1296 struct ftrace_graph_ent_entry *field;
1297 struct fgraph_data *data = iter->private;
1298 struct trace_entry *entry = iter->ent;
1299 struct trace_seq *s = &iter->seq;
1300 int cpu = iter->cpu;
1301 int ret;
1302
1303 if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
1304 per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
1305 return TRACE_TYPE_HANDLED;
1306 }
1307
1308 /*
1309 * If the last output failed, there's a possibility we need
1310 * to print out the missing entry which would never go out.
1311 */
1312 if (data && data->failed) {
1313 field = &data->ent.ent;
1314 iter->cpu = data->cpu;
1315 ret = print_graph_entry(field, s, iter, flags);
1316 if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
1317 per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
1318 ret = TRACE_TYPE_NO_CONSUME;
1319 }
1320 iter->cpu = cpu;
1321 return ret;
1322 }
1323
1324 switch (entry->type) {
1325 case TRACE_GRAPH_ENT: {
1326 /*
1327 * print_graph_entry() may consume the current event,
1328 * thus @field may become invalid, so we need to save it.
1329 * sizeof(struct ftrace_graph_ent_entry) is very small,
1330 * it can be safely saved at the stack.
1331 */
1332 struct ftrace_graph_ent_entry saved;
1333 trace_assign_type(field, entry);
1334 saved = *field;
1335 return print_graph_entry(&saved, s, iter, flags);
1336 }
1337#ifdef CONFIG_FUNCTION_GRAPH_RETADDR
1338 case TRACE_GRAPH_RETADDR_ENT: {
1339 struct fgraph_retaddr_ent_entry saved;
1340 struct fgraph_retaddr_ent_entry *rfield;
1341
1342 trace_assign_type(rfield, entry);
1343 saved = *rfield;
1344 return print_graph_entry((struct ftrace_graph_ent_entry *)&saved, s, iter, flags);
1345 }
1346#endif
1347 case TRACE_GRAPH_RET: {
1348 struct ftrace_graph_ret_entry *field;
1349 trace_assign_type(field, entry);
1350 return print_graph_return(&field->ret, s, entry, iter, flags);
1351 }
1352 case TRACE_STACK:
1353 case TRACE_FN:
1354 /* dont trace stack and functions as comments */
1355 return TRACE_TYPE_UNHANDLED;
1356
1357 default:
1358 return print_graph_comment(s, entry, iter, flags);
1359 }
1360
1361 return TRACE_TYPE_HANDLED;
1362}
1363
1364static enum print_line_t
1365print_graph_function(struct trace_iterator *iter)
1366{
1367 return print_graph_function_flags(iter, tracer_flags.val);
1368}
1369
1370static enum print_line_t
1371print_graph_function_event(struct trace_iterator *iter, int flags,
1372 struct trace_event *event)
1373{
1374 return print_graph_function(iter);
1375}
1376
1377static void print_lat_header(struct seq_file *s, u32 flags)
1378{
1379 static const char spaces[] = " " /* 16 spaces */
1380 " " /* 4 spaces */
1381 " "; /* 17 spaces */
1382 int size = 0;
1383
1384 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1385 size += 16;
1386 if (flags & TRACE_GRAPH_PRINT_REL_TIME)
1387 size += 16;
1388 if (flags & TRACE_GRAPH_PRINT_CPU)
1389 size += 4;
1390 if (flags & TRACE_GRAPH_PRINT_PROC)
1391 size += 17;
1392
1393 seq_printf(s, "#%.*s _-----=> irqs-off \n", size, spaces);
1394 seq_printf(s, "#%.*s / _----=> need-resched \n", size, spaces);
1395 seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
1396 seq_printf(s, "#%.*s|| / _--=> preempt-depth \n", size, spaces);
1397 seq_printf(s, "#%.*s||| / \n", size, spaces);
1398}
1399
1400static void __print_graph_headers_flags(struct trace_array *tr,
1401 struct seq_file *s, u32 flags)
1402{
1403 int lat = tr->trace_flags & TRACE_ITER_LATENCY_FMT;
1404
1405 if (lat)
1406 print_lat_header(s, flags);
1407
1408 /* 1st line */
1409 seq_putc(s, '#');
1410 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1411 seq_puts(s, " TIME ");
1412 if (flags & TRACE_GRAPH_PRINT_REL_TIME)
1413 seq_puts(s, " REL TIME ");
1414 if (flags & TRACE_GRAPH_PRINT_CPU)
1415 seq_puts(s, " CPU");
1416 if (flags & TRACE_GRAPH_PRINT_PROC)
1417 seq_puts(s, " TASK/PID ");
1418 if (lat)
1419 seq_puts(s, "|||| ");
1420 if (flags & TRACE_GRAPH_PRINT_DURATION)
1421 seq_puts(s, " DURATION ");
1422 seq_puts(s, " FUNCTION CALLS\n");
1423
1424 /* 2nd line */
1425 seq_putc(s, '#');
1426 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1427 seq_puts(s, " | ");
1428 if (flags & TRACE_GRAPH_PRINT_REL_TIME)
1429 seq_puts(s, " | ");
1430 if (flags & TRACE_GRAPH_PRINT_CPU)
1431 seq_puts(s, " | ");
1432 if (flags & TRACE_GRAPH_PRINT_PROC)
1433 seq_puts(s, " | | ");
1434 if (lat)
1435 seq_puts(s, "|||| ");
1436 if (flags & TRACE_GRAPH_PRINT_DURATION)
1437 seq_puts(s, " | | ");
1438 seq_puts(s, " | | | |\n");
1439}
1440
1441static void print_graph_headers(struct seq_file *s)
1442{
1443 print_graph_headers_flags(s, tracer_flags.val);
1444}
1445
1446void print_graph_headers_flags(struct seq_file *s, u32 flags)
1447{
1448 struct trace_iterator *iter = s->private;
1449 struct trace_array *tr = iter->tr;
1450
1451 if (!(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
1452 return;
1453
1454 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT) {
1455 /* print nothing if the buffers are empty */
1456 if (trace_empty(iter))
1457 return;
1458
1459 print_trace_header(s, iter);
1460 }
1461
1462 __print_graph_headers_flags(tr, s, flags);
1463}
1464
1465void graph_trace_open(struct trace_iterator *iter)
1466{
1467 /* pid and depth on the last trace processed */
1468 struct fgraph_data *data;
1469 gfp_t gfpflags;
1470 int cpu;
1471
1472 iter->private = NULL;
1473
1474 /* We can be called in atomic context via ftrace_dump() */
1475 gfpflags = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL;
1476
1477 data = kzalloc(sizeof(*data), gfpflags);
1478 if (!data)
1479 goto out_err;
1480
1481 data->cpu_data = alloc_percpu_gfp(struct fgraph_cpu_data, gfpflags);
1482 if (!data->cpu_data)
1483 goto out_err_free;
1484
1485 for_each_possible_cpu(cpu) {
1486 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
1487 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
1488 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
1489 int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1490
1491 *pid = -1;
1492 *depth = 0;
1493 *ignore = 0;
1494 *depth_irq = -1;
1495 }
1496
1497 iter->private = data;
1498
1499 return;
1500
1501 out_err_free:
1502 kfree(data);
1503 out_err:
1504 pr_warn("function graph tracer: not enough memory\n");
1505}
1506
1507void graph_trace_close(struct trace_iterator *iter)
1508{
1509 struct fgraph_data *data = iter->private;
1510
1511 if (data) {
1512 free_percpu(data->cpu_data);
1513 kfree(data);
1514 }
1515}
1516
1517static int
1518func_graph_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1519{
1520 if (bit == TRACE_GRAPH_PRINT_IRQS)
1521 ftrace_graph_skip_irqs = !set;
1522
1523 if (bit == TRACE_GRAPH_SLEEP_TIME)
1524 ftrace_graph_sleep_time_control(set);
1525
1526 if (bit == TRACE_GRAPH_GRAPH_TIME)
1527 ftrace_graph_graph_time_control(set);
1528
1529 return 0;
1530}
1531
1532static struct trace_event_functions graph_functions = {
1533 .trace = print_graph_function_event,
1534};
1535
1536static struct trace_event graph_trace_entry_event = {
1537 .type = TRACE_GRAPH_ENT,
1538 .funcs = &graph_functions,
1539};
1540
1541#ifdef CONFIG_FUNCTION_GRAPH_RETADDR
1542static struct trace_event graph_trace_retaddr_entry_event = {
1543 .type = TRACE_GRAPH_RETADDR_ENT,
1544 .funcs = &graph_functions,
1545};
1546#endif
1547
1548static struct trace_event graph_trace_ret_event = {
1549 .type = TRACE_GRAPH_RET,
1550 .funcs = &graph_functions
1551};
1552
1553static struct tracer graph_trace __tracer_data = {
1554 .name = "function_graph",
1555 .update_thresh = graph_trace_update_thresh,
1556 .open = graph_trace_open,
1557 .pipe_open = graph_trace_open,
1558 .close = graph_trace_close,
1559 .pipe_close = graph_trace_close,
1560 .init = graph_trace_init,
1561 .reset = graph_trace_reset,
1562 .print_line = print_graph_function,
1563 .print_header = print_graph_headers,
1564 .flags = &tracer_flags,
1565 .set_flag = func_graph_set_flag,
1566 .allow_instances = true,
1567#ifdef CONFIG_FTRACE_SELFTEST
1568 .selftest = trace_selftest_startup_function_graph,
1569#endif
1570};
1571
1572
1573static ssize_t
1574graph_depth_write(struct file *filp, const char __user *ubuf, size_t cnt,
1575 loff_t *ppos)
1576{
1577 unsigned long val;
1578 int ret;
1579
1580 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1581 if (ret)
1582 return ret;
1583
1584 fgraph_max_depth = val;
1585
1586 *ppos += cnt;
1587
1588 return cnt;
1589}
1590
1591static ssize_t
1592graph_depth_read(struct file *filp, char __user *ubuf, size_t cnt,
1593 loff_t *ppos)
1594{
1595 char buf[15]; /* More than enough to hold UINT_MAX + "\n"*/
1596 int n;
1597
1598 n = sprintf(buf, "%d\n", fgraph_max_depth);
1599
1600 return simple_read_from_buffer(ubuf, cnt, ppos, buf, n);
1601}
1602
1603static const struct file_operations graph_depth_fops = {
1604 .open = tracing_open_generic,
1605 .write = graph_depth_write,
1606 .read = graph_depth_read,
1607 .llseek = generic_file_llseek,
1608};
1609
1610static __init int init_graph_tracefs(void)
1611{
1612 int ret;
1613
1614 ret = tracing_init_dentry();
1615 if (ret)
1616 return 0;
1617
1618 trace_create_file("max_graph_depth", TRACE_MODE_WRITE, NULL,
1619 NULL, &graph_depth_fops);
1620
1621 return 0;
1622}
1623fs_initcall(init_graph_tracefs);
1624
1625static __init int init_graph_trace(void)
1626{
1627 max_bytes_for_cpu = snprintf(NULL, 0, "%u", nr_cpu_ids - 1);
1628
1629 if (!register_trace_event(&graph_trace_entry_event)) {
1630 pr_warn("Warning: could not register graph trace events\n");
1631 return 1;
1632 }
1633
1634#ifdef CONFIG_FUNCTION_GRAPH_RETADDR
1635 if (!register_trace_event(&graph_trace_retaddr_entry_event)) {
1636 pr_warn("Warning: could not register graph trace retaddr events\n");
1637 return 1;
1638 }
1639#endif
1640
1641 if (!register_trace_event(&graph_trace_ret_event)) {
1642 pr_warn("Warning: could not register graph trace events\n");
1643 return 1;
1644 }
1645
1646 return register_tracer(&graph_trace);
1647}
1648
1649core_initcall(init_graph_trace);