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>
9 #include <linux/debugfs.h>
10 #include <linux/uaccess.h>
11 #include <linux/ftrace.h>
15 #include "trace_output.h"
22 #define TRACE_GRAPH_INDENT 2
25 #define TRACE_GRAPH_PRINT_OVERRUN 0x1
26 #define TRACE_GRAPH_PRINT_CPU 0x2
27 #define TRACE_GRAPH_PRINT_OVERHEAD 0x4
28 #define TRACE_GRAPH_PRINT_PROC 0x8
29 #define TRACE_GRAPH_PRINT_DURATION 0x10
30 #define TRACE_GRAPH_PRINT_ABS_TIME 0X20
32 static struct tracer_opt trace_opts[] = {
33 /* Display overruns? (for self-debug purpose) */
34 { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
36 { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
37 /* Display Overhead ? */
38 { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
39 /* Display proc name/pid */
40 { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
41 /* Display duration of execution */
42 { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
43 /* Display absolute time of an entry */
44 { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
48 static struct tracer_flags tracer_flags = {
49 /* Don't display overruns and proc by default */
50 .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
51 TRACE_GRAPH_PRINT_DURATION,
55 static struct trace_array *graph_array;
58 /* Add a function return address to the trace stack on thread info.*/
60 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
61 unsigned long frame_pointer)
63 unsigned long long calltime;
66 if (!current->ret_stack)
70 * We must make sure the ret_stack is tested before we read
75 /* The return trace stack is full */
76 if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
77 atomic_inc(¤t->trace_overrun);
81 calltime = trace_clock_local();
83 index = ++current->curr_ret_stack;
85 current->ret_stack[index].ret = ret;
86 current->ret_stack[index].func = func;
87 current->ret_stack[index].calltime = calltime;
88 current->ret_stack[index].subtime = 0;
89 current->ret_stack[index].fp = frame_pointer;
95 /* Retrieve a function return address to the trace stack on thread info.*/
97 ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
98 unsigned long frame_pointer)
102 index = current->curr_ret_stack;
104 if (unlikely(index < 0)) {
107 /* Might as well panic, otherwise we have no where to go */
108 *ret = (unsigned long)panic;
112 #ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST
114 * The arch may choose to record the frame pointer used
115 * and check it here to make sure that it is what we expect it
116 * to be. If gcc does not set the place holder of the return
117 * address in the frame pointer, and does a copy instead, then
118 * the function graph trace will fail. This test detects this
121 * Currently, x86_32 with optimize for size (-Os) makes the latest
124 if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
126 WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
127 " from func %pF return to %lx\n",
128 current->ret_stack[index].fp,
130 (void *)current->ret_stack[index].func,
131 current->ret_stack[index].ret);
132 *ret = (unsigned long)panic;
137 *ret = current->ret_stack[index].ret;
138 trace->func = current->ret_stack[index].func;
139 trace->calltime = current->ret_stack[index].calltime;
140 trace->overrun = atomic_read(¤t->trace_overrun);
141 trace->depth = index;
145 * Send the trace to the ring-buffer.
146 * @return the original return address.
148 unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
150 struct ftrace_graph_ret trace;
153 ftrace_pop_return_trace(&trace, &ret, frame_pointer);
154 trace.rettime = trace_clock_local();
155 ftrace_graph_return(&trace);
157 current->curr_ret_stack--;
159 if (unlikely(!ret)) {
162 /* Might as well panic. What else to do? */
163 ret = (unsigned long)panic;
169 static int __trace_graph_entry(struct trace_array *tr,
170 struct ftrace_graph_ent *trace,
174 struct ftrace_event_call *call = &event_funcgraph_entry;
175 struct ring_buffer_event *event;
176 struct ring_buffer *buffer = tr->buffer;
177 struct ftrace_graph_ent_entry *entry;
179 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
182 event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
183 sizeof(*entry), flags, pc);
186 entry = ring_buffer_event_data(event);
187 entry->graph_ent = *trace;
188 if (!filter_current_check_discard(buffer, call, entry, event))
189 ring_buffer_unlock_commit(buffer, event);
194 int trace_graph_entry(struct ftrace_graph_ent *trace)
196 struct trace_array *tr = graph_array;
197 struct trace_array_cpu *data;
207 if (!ftrace_trace_task(current))
210 if (!ftrace_graph_addr(trace->func))
213 local_irq_save(flags);
214 cpu = raw_smp_processor_id();
215 data = tr->data[cpu];
216 disabled = atomic_inc_return(&data->disabled);
217 if (likely(disabled == 1)) {
218 pc = preempt_count();
219 ret = __trace_graph_entry(tr, trace, flags, pc);
223 /* Only do the atomic if it is not already set */
224 if (!test_tsk_trace_graph(current))
225 set_tsk_trace_graph(current);
227 atomic_dec(&data->disabled);
228 local_irq_restore(flags);
233 static void __trace_graph_return(struct trace_array *tr,
234 struct ftrace_graph_ret *trace,
238 struct ftrace_event_call *call = &event_funcgraph_exit;
239 struct ring_buffer_event *event;
240 struct ring_buffer *buffer = tr->buffer;
241 struct ftrace_graph_ret_entry *entry;
243 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
246 event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
247 sizeof(*entry), flags, pc);
250 entry = ring_buffer_event_data(event);
252 if (!filter_current_check_discard(buffer, call, entry, event))
253 ring_buffer_unlock_commit(buffer, event);
256 void trace_graph_return(struct ftrace_graph_ret *trace)
258 struct trace_array *tr = graph_array;
259 struct trace_array_cpu *data;
265 local_irq_save(flags);
266 cpu = raw_smp_processor_id();
267 data = tr->data[cpu];
268 disabled = atomic_inc_return(&data->disabled);
269 if (likely(disabled == 1)) {
270 pc = preempt_count();
271 __trace_graph_return(tr, trace, flags, pc);
274 clear_tsk_trace_graph(current);
275 atomic_dec(&data->disabled);
276 local_irq_restore(flags);
279 static int graph_trace_init(struct trace_array *tr)
284 ret = register_ftrace_graph(&trace_graph_return,
288 tracing_start_cmdline_record();
293 void set_graph_array(struct trace_array *tr)
298 static void graph_trace_reset(struct trace_array *tr)
300 tracing_stop_cmdline_record();
301 unregister_ftrace_graph();
304 static int max_bytes_for_cpu;
306 static enum print_line_t
307 print_graph_cpu(struct trace_seq *s, int cpu)
312 * Start with a space character - to make it stand out
313 * to the right a bit when trace output is pasted into
316 ret = trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
318 return TRACE_TYPE_PARTIAL_LINE;
320 return TRACE_TYPE_HANDLED;
323 #define TRACE_GRAPH_PROCINFO_LENGTH 14
325 static enum print_line_t
326 print_graph_proc(struct trace_seq *s, pid_t pid)
328 char comm[TASK_COMM_LEN];
329 /* sign + log10(MAX_INT) + '\0' */
336 trace_find_cmdline(pid, comm);
338 sprintf(pid_str, "%d", pid);
340 /* 1 stands for the "-" character */
341 len = strlen(comm) + strlen(pid_str) + 1;
343 if (len < TRACE_GRAPH_PROCINFO_LENGTH)
344 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
346 /* First spaces to align center */
347 for (i = 0; i < spaces / 2; i++) {
348 ret = trace_seq_printf(s, " ");
350 return TRACE_TYPE_PARTIAL_LINE;
353 ret = trace_seq_printf(s, "%s-%s", comm, pid_str);
355 return TRACE_TYPE_PARTIAL_LINE;
357 /* Last spaces to align center */
358 for (i = 0; i < spaces - (spaces / 2); i++) {
359 ret = trace_seq_printf(s, " ");
361 return TRACE_TYPE_PARTIAL_LINE;
363 return TRACE_TYPE_HANDLED;
367 /* If the pid changed since the last trace, output this event */
368 static enum print_line_t
369 verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
376 return TRACE_TYPE_HANDLED;
378 last_pid = &(per_cpu_ptr(data, cpu)->last_pid);
380 if (*last_pid == pid)
381 return TRACE_TYPE_HANDLED;
383 prev_pid = *last_pid;
387 return TRACE_TYPE_HANDLED;
389 * Context-switch trace line:
391 ------------------------------------------
392 | 1) migration/0--1 => sshd-1755
393 ------------------------------------------
396 ret = trace_seq_printf(s,
397 " ------------------------------------------\n");
399 return TRACE_TYPE_PARTIAL_LINE;
401 ret = print_graph_cpu(s, cpu);
402 if (ret == TRACE_TYPE_PARTIAL_LINE)
403 return TRACE_TYPE_PARTIAL_LINE;
405 ret = print_graph_proc(s, prev_pid);
406 if (ret == TRACE_TYPE_PARTIAL_LINE)
407 return TRACE_TYPE_PARTIAL_LINE;
409 ret = trace_seq_printf(s, " => ");
411 return TRACE_TYPE_PARTIAL_LINE;
413 ret = print_graph_proc(s, pid);
414 if (ret == TRACE_TYPE_PARTIAL_LINE)
415 return TRACE_TYPE_PARTIAL_LINE;
417 ret = trace_seq_printf(s,
418 "\n ------------------------------------------\n\n");
420 return TRACE_TYPE_PARTIAL_LINE;
422 return TRACE_TYPE_HANDLED;
425 static struct ftrace_graph_ret_entry *
426 get_return_for_leaf(struct trace_iterator *iter,
427 struct ftrace_graph_ent_entry *curr)
429 struct ring_buffer_iter *ring_iter;
430 struct ring_buffer_event *event;
431 struct ftrace_graph_ret_entry *next;
433 ring_iter = iter->buffer_iter[iter->cpu];
435 /* First peek to compare current entry and the next one */
437 event = ring_buffer_iter_peek(ring_iter, NULL);
439 /* We need to consume the current entry to see the next one */
440 ring_buffer_consume(iter->tr->buffer, iter->cpu, NULL);
441 event = ring_buffer_peek(iter->tr->buffer, iter->cpu,
448 next = ring_buffer_event_data(event);
450 if (next->ent.type != TRACE_GRAPH_RET)
453 if (curr->ent.pid != next->ent.pid ||
454 curr->graph_ent.func != next->ret.func)
457 /* this is a leaf, now advance the iterator */
459 ring_buffer_read(ring_iter, NULL);
464 /* Signal a overhead of time execution to the output */
466 print_graph_overhead(unsigned long long duration, struct trace_seq *s)
468 /* If duration disappear, we don't need anything */
469 if (!(tracer_flags.val & TRACE_GRAPH_PRINT_DURATION))
472 /* Non nested entry or return */
474 return trace_seq_printf(s, " ");
476 if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
477 /* Duration exceeded 100 msecs */
478 if (duration > 100000ULL)
479 return trace_seq_printf(s, "! ");
481 /* Duration exceeded 10 msecs */
482 if (duration > 10000ULL)
483 return trace_seq_printf(s, "+ ");
486 return trace_seq_printf(s, " ");
489 static int print_graph_abs_time(u64 t, struct trace_seq *s)
491 unsigned long usecs_rem;
493 usecs_rem = do_div(t, NSEC_PER_SEC);
496 return trace_seq_printf(s, "%5lu.%06lu | ",
497 (unsigned long)t, usecs_rem);
500 static enum print_line_t
501 print_graph_irq(struct trace_iterator *iter, unsigned long addr,
502 enum trace_type type, int cpu, pid_t pid)
505 struct trace_seq *s = &iter->seq;
507 if (addr < (unsigned long)__irqentry_text_start ||
508 addr >= (unsigned long)__irqentry_text_end)
509 return TRACE_TYPE_UNHANDLED;
512 if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
513 ret = print_graph_abs_time(iter->ts, s);
515 return TRACE_TYPE_PARTIAL_LINE;
519 if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
520 ret = print_graph_cpu(s, cpu);
521 if (ret == TRACE_TYPE_PARTIAL_LINE)
522 return TRACE_TYPE_PARTIAL_LINE;
525 if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
526 ret = print_graph_proc(s, pid);
527 if (ret == TRACE_TYPE_PARTIAL_LINE)
528 return TRACE_TYPE_PARTIAL_LINE;
529 ret = trace_seq_printf(s, " | ");
531 return TRACE_TYPE_PARTIAL_LINE;
535 ret = print_graph_overhead(-1, s);
537 return TRACE_TYPE_PARTIAL_LINE;
539 if (type == TRACE_GRAPH_ENT)
540 ret = trace_seq_printf(s, "==========>");
542 ret = trace_seq_printf(s, "<==========");
545 return TRACE_TYPE_PARTIAL_LINE;
547 /* Don't close the duration column if haven't one */
548 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
549 trace_seq_printf(s, " |");
550 ret = trace_seq_printf(s, "\n");
553 return TRACE_TYPE_PARTIAL_LINE;
554 return TRACE_TYPE_HANDLED;
558 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
560 unsigned long nsecs_rem = do_div(duration, 1000);
561 /* log10(ULONG_MAX) + '\0' */
567 sprintf(msecs_str, "%lu", (unsigned long) duration);
570 ret = trace_seq_printf(s, "%s", msecs_str);
572 return TRACE_TYPE_PARTIAL_LINE;
574 len = strlen(msecs_str);
576 /* Print nsecs (we don't want to exceed 7 numbers) */
578 snprintf(nsecs_str, 8 - len, "%03lu", nsecs_rem);
579 ret = trace_seq_printf(s, ".%s", nsecs_str);
581 return TRACE_TYPE_PARTIAL_LINE;
582 len += strlen(nsecs_str);
585 ret = trace_seq_printf(s, " us ");
587 return TRACE_TYPE_PARTIAL_LINE;
589 /* Print remaining spaces to fit the row's width */
590 for (i = len; i < 7; i++) {
591 ret = trace_seq_printf(s, " ");
593 return TRACE_TYPE_PARTIAL_LINE;
595 return TRACE_TYPE_HANDLED;
598 static enum print_line_t
599 print_graph_duration(unsigned long long duration, struct trace_seq *s)
603 ret = trace_print_graph_duration(duration, s);
604 if (ret != TRACE_TYPE_HANDLED)
607 ret = trace_seq_printf(s, "| ");
609 return TRACE_TYPE_PARTIAL_LINE;
611 return TRACE_TYPE_HANDLED;
614 /* Case of a leaf function on its call entry */
615 static enum print_line_t
616 print_graph_entry_leaf(struct trace_iterator *iter,
617 struct ftrace_graph_ent_entry *entry,
618 struct ftrace_graph_ret_entry *ret_entry, struct trace_seq *s)
620 struct fgraph_data *data = iter->private;
621 struct ftrace_graph_ret *graph_ret;
622 struct ftrace_graph_ent *call;
623 unsigned long long duration;
627 graph_ret = &ret_entry->ret;
628 call = &entry->graph_ent;
629 duration = graph_ret->rettime - graph_ret->calltime;
633 int *depth = &(per_cpu_ptr(data, cpu)->depth);
636 * Comments display at + 1 to depth. Since
637 * this is a leaf function, keep the comments
638 * equal to this depth.
640 *depth = call->depth - 1;
644 ret = print_graph_overhead(duration, s);
646 return TRACE_TYPE_PARTIAL_LINE;
649 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
650 ret = print_graph_duration(duration, s);
651 if (ret == TRACE_TYPE_PARTIAL_LINE)
652 return TRACE_TYPE_PARTIAL_LINE;
656 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
657 ret = trace_seq_printf(s, " ");
659 return TRACE_TYPE_PARTIAL_LINE;
662 ret = trace_seq_printf(s, "%pf();\n", (void *)call->func);
664 return TRACE_TYPE_PARTIAL_LINE;
666 return TRACE_TYPE_HANDLED;
669 static enum print_line_t
670 print_graph_entry_nested(struct trace_iterator *iter,
671 struct ftrace_graph_ent_entry *entry,
672 struct trace_seq *s, int cpu)
674 struct ftrace_graph_ent *call = &entry->graph_ent;
675 struct fgraph_data *data = iter->private;
681 int *depth = &(per_cpu_ptr(data, cpu)->depth);
683 *depth = call->depth;
687 ret = print_graph_overhead(-1, s);
689 return TRACE_TYPE_PARTIAL_LINE;
692 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
693 ret = trace_seq_printf(s, " | ");
695 return TRACE_TYPE_PARTIAL_LINE;
699 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
700 ret = trace_seq_printf(s, " ");
702 return TRACE_TYPE_PARTIAL_LINE;
705 ret = trace_seq_printf(s, "%pf() {\n", (void *)call->func);
707 return TRACE_TYPE_PARTIAL_LINE;
710 * we already consumed the current entry to check the next one
711 * and see if this is a leaf.
713 return TRACE_TYPE_NO_CONSUME;
716 static enum print_line_t
717 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
718 int type, unsigned long addr)
720 struct fgraph_data *data = iter->private;
721 struct trace_entry *ent = iter->ent;
726 if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)
727 return TRACE_TYPE_PARTIAL_LINE;
731 ret = print_graph_irq(iter, addr, type, cpu, ent->pid);
732 if (ret == TRACE_TYPE_PARTIAL_LINE)
733 return TRACE_TYPE_PARTIAL_LINE;
737 if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
738 ret = print_graph_abs_time(iter->ts, s);
740 return TRACE_TYPE_PARTIAL_LINE;
744 if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
745 ret = print_graph_cpu(s, cpu);
746 if (ret == TRACE_TYPE_PARTIAL_LINE)
747 return TRACE_TYPE_PARTIAL_LINE;
751 if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
752 ret = print_graph_proc(s, ent->pid);
753 if (ret == TRACE_TYPE_PARTIAL_LINE)
754 return TRACE_TYPE_PARTIAL_LINE;
756 ret = trace_seq_printf(s, " | ");
758 return TRACE_TYPE_PARTIAL_LINE;
764 static enum print_line_t
765 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
766 struct trace_iterator *iter)
769 struct ftrace_graph_ent *call = &field->graph_ent;
770 struct ftrace_graph_ret_entry *leaf_ret;
772 if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func))
773 return TRACE_TYPE_PARTIAL_LINE;
775 leaf_ret = get_return_for_leaf(iter, field);
777 return print_graph_entry_leaf(iter, field, leaf_ret, s);
779 return print_graph_entry_nested(iter, field, s, cpu);
783 static enum print_line_t
784 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
785 struct trace_entry *ent, struct trace_iterator *iter)
787 unsigned long long duration = trace->rettime - trace->calltime;
788 struct fgraph_data *data = iter->private;
789 pid_t pid = ent->pid;
796 int *depth = &(per_cpu_ptr(data, cpu)->depth);
799 * Comments display at + 1 to depth. This is the
800 * return from a function, we now want the comments
801 * to display at the same level of the bracket.
803 *depth = trace->depth - 1;
806 if (print_graph_prologue(iter, s, 0, 0))
807 return TRACE_TYPE_PARTIAL_LINE;
810 ret = print_graph_overhead(duration, s);
812 return TRACE_TYPE_PARTIAL_LINE;
815 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
816 ret = print_graph_duration(duration, s);
817 if (ret == TRACE_TYPE_PARTIAL_LINE)
818 return TRACE_TYPE_PARTIAL_LINE;
822 for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
823 ret = trace_seq_printf(s, " ");
825 return TRACE_TYPE_PARTIAL_LINE;
828 ret = trace_seq_printf(s, "}\n");
830 return TRACE_TYPE_PARTIAL_LINE;
833 if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERRUN) {
834 ret = trace_seq_printf(s, " (Overruns: %lu)\n",
837 return TRACE_TYPE_PARTIAL_LINE;
840 ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET, cpu, pid);
841 if (ret == TRACE_TYPE_PARTIAL_LINE)
842 return TRACE_TYPE_PARTIAL_LINE;
844 return TRACE_TYPE_HANDLED;
847 static enum print_line_t
848 print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
849 struct trace_iterator *iter)
851 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
852 struct fgraph_data *data = iter->private;
853 struct trace_event *event;
859 depth = per_cpu_ptr(data, iter->cpu)->depth;
861 if (print_graph_prologue(iter, s, 0, 0))
862 return TRACE_TYPE_PARTIAL_LINE;
865 ret = print_graph_overhead(-1, s);
867 return TRACE_TYPE_PARTIAL_LINE;
870 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
871 ret = trace_seq_printf(s, " | ");
873 return TRACE_TYPE_PARTIAL_LINE;
878 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) {
879 ret = trace_seq_printf(s, " ");
881 return TRACE_TYPE_PARTIAL_LINE;
885 ret = trace_seq_printf(s, "/* ");
887 return TRACE_TYPE_PARTIAL_LINE;
889 switch (iter->ent->type) {
891 ret = trace_print_bprintk_msg_only(iter);
892 if (ret != TRACE_TYPE_HANDLED)
896 ret = trace_print_printk_msg_only(iter);
897 if (ret != TRACE_TYPE_HANDLED)
901 event = ftrace_find_event(ent->type);
903 return TRACE_TYPE_UNHANDLED;
905 ret = event->trace(iter, sym_flags);
906 if (ret != TRACE_TYPE_HANDLED)
910 /* Strip ending newline */
911 if (s->buffer[s->len - 1] == '\n') {
912 s->buffer[s->len - 1] = '\0';
916 ret = trace_seq_printf(s, " */\n");
918 return TRACE_TYPE_PARTIAL_LINE;
920 return TRACE_TYPE_HANDLED;
925 print_graph_function(struct trace_iterator *iter)
927 struct trace_entry *entry = iter->ent;
928 struct trace_seq *s = &iter->seq;
930 switch (entry->type) {
931 case TRACE_GRAPH_ENT: {
933 * print_graph_entry() may consume the current event,
934 * thus @field may become invalid, so we need to save it.
935 * sizeof(struct ftrace_graph_ent_entry) is very small,
936 * it can be safely saved at the stack.
938 struct ftrace_graph_ent_entry *field, saved;
939 trace_assign_type(field, entry);
941 return print_graph_entry(&saved, s, iter);
943 case TRACE_GRAPH_RET: {
944 struct ftrace_graph_ret_entry *field;
945 trace_assign_type(field, entry);
946 return print_graph_return(&field->ret, s, entry, iter);
949 return print_graph_comment(s, entry, iter);
952 return TRACE_TYPE_HANDLED;
955 static void print_graph_headers(struct seq_file *s)
959 if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
960 seq_printf(s, " TIME ");
961 if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
962 seq_printf(s, "CPU");
963 if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
964 seq_printf(s, " TASK/PID ");
965 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
966 seq_printf(s, " DURATION ");
967 seq_printf(s, " FUNCTION CALLS\n");
971 if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
972 seq_printf(s, " | ");
973 if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
975 if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
976 seq_printf(s, " | | ");
977 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
978 seq_printf(s, " | | ");
979 seq_printf(s, " | | | |\n");
982 static void graph_trace_open(struct trace_iterator *iter)
984 /* pid and depth on the last trace processed */
985 struct fgraph_data *data = alloc_percpu(struct fgraph_data);
989 pr_warning("function graph tracer: not enough memory\n");
991 for_each_possible_cpu(cpu) {
992 pid_t *pid = &(per_cpu_ptr(data, cpu)->last_pid);
993 int *depth = &(per_cpu_ptr(data, cpu)->depth);
998 iter->private = data;
1001 static void graph_trace_close(struct trace_iterator *iter)
1003 free_percpu(iter->private);
1006 static struct tracer graph_trace __read_mostly = {
1007 .name = "function_graph",
1008 .open = graph_trace_open,
1009 .close = graph_trace_close,
1010 .wait_pipe = poll_wait_pipe,
1011 .init = graph_trace_init,
1012 .reset = graph_trace_reset,
1013 .print_line = print_graph_function,
1014 .print_header = print_graph_headers,
1015 .flags = &tracer_flags,
1016 #ifdef CONFIG_FTRACE_SELFTEST
1017 .selftest = trace_selftest_startup_function_graph,
1021 static __init int init_graph_trace(void)
1023 max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);
1025 return register_tracer(&graph_trace);
1028 device_initcall(init_graph_trace);