GNU Linux-libre 4.9.306-gnu1
[releases.git] / kernel / trace / trace_functions_graph.c
1 /*
2  *
3  * Function graph tracer.
4  * Copyright (c) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com>
5  * Mostly borrowed from function tracer which
6  * is Copyright (c) Steven Rostedt <srostedt@redhat.com>
7  *
8  */
9 #include <linux/uaccess.h>
10 #include <linux/ftrace.h>
11 #include <linux/interrupt.h>
12 #include <linux/slab.h>
13 #include <linux/fs.h>
14
15 #include "trace.h"
16 #include "trace_output.h"
17
18 static bool kill_ftrace_graph;
19
20 /**
21  * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called
22  *
23  * ftrace_graph_stop() is called when a severe error is detected in
24  * the function graph tracing. This function is called by the critical
25  * paths of function graph to keep those paths from doing any more harm.
26  */
27 bool ftrace_graph_is_dead(void)
28 {
29         return kill_ftrace_graph;
30 }
31
32 /**
33  * ftrace_graph_stop - set to permanently disable function graph tracincg
34  *
35  * In case of an error int function graph tracing, this is called
36  * to try to keep function graph tracing from causing any more harm.
37  * Usually this is pretty severe and this is called to try to at least
38  * get a warning out to the user.
39  */
40 void ftrace_graph_stop(void)
41 {
42         kill_ftrace_graph = true;
43 }
44
45 /* When set, irq functions will be ignored */
46 static int ftrace_graph_skip_irqs;
47
48 struct fgraph_cpu_data {
49         pid_t           last_pid;
50         int             depth;
51         int             depth_irq;
52         int             ignore;
53         unsigned long   enter_funcs[FTRACE_RETFUNC_DEPTH];
54 };
55
56 struct fgraph_data {
57         struct fgraph_cpu_data __percpu *cpu_data;
58
59         /* Place to preserve last processed entry. */
60         struct ftrace_graph_ent_entry   ent;
61         struct ftrace_graph_ret_entry   ret;
62         int                             failed;
63         int                             cpu;
64 };
65
66 #define TRACE_GRAPH_INDENT      2
67
68 static unsigned int max_depth;
69
70 static struct tracer_opt trace_opts[] = {
71         /* Display overruns? (for self-debug purpose) */
72         { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
73         /* Display CPU ? */
74         { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
75         /* Display Overhead ? */
76         { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
77         /* Display proc name/pid */
78         { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
79         /* Display duration of execution */
80         { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
81         /* Display absolute time of an entry */
82         { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
83         /* Display interrupts */
84         { TRACER_OPT(funcgraph-irqs, TRACE_GRAPH_PRINT_IRQS) },
85         /* Display function name after trailing } */
86         { TRACER_OPT(funcgraph-tail, TRACE_GRAPH_PRINT_TAIL) },
87         /* Include sleep time (scheduled out) between entry and return */
88         { TRACER_OPT(sleep-time, TRACE_GRAPH_SLEEP_TIME) },
89         /* Include time within nested functions */
90         { TRACER_OPT(graph-time, TRACE_GRAPH_GRAPH_TIME) },
91         { } /* Empty entry */
92 };
93
94 static struct tracer_flags tracer_flags = {
95         /* Don't display overruns, proc, or tail by default */
96         .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
97                TRACE_GRAPH_PRINT_DURATION | TRACE_GRAPH_PRINT_IRQS |
98                TRACE_GRAPH_SLEEP_TIME | TRACE_GRAPH_GRAPH_TIME,
99         .opts = trace_opts
100 };
101
102 static struct trace_array *graph_array;
103
104 /*
105  * DURATION column is being also used to display IRQ signs,
106  * following values are used by print_graph_irq and others
107  * to fill in space into DURATION column.
108  */
109 enum {
110         FLAGS_FILL_FULL  = 1 << TRACE_GRAPH_PRINT_FILL_SHIFT,
111         FLAGS_FILL_START = 2 << TRACE_GRAPH_PRINT_FILL_SHIFT,
112         FLAGS_FILL_END   = 3 << TRACE_GRAPH_PRINT_FILL_SHIFT,
113 };
114
115 static void
116 print_graph_duration(struct trace_array *tr, unsigned long long duration,
117                      struct trace_seq *s, u32 flags);
118
119 /* Add a function return address to the trace stack on thread info.*/
120 int
121 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
122                          unsigned long frame_pointer, unsigned long *retp)
123 {
124         unsigned long long calltime;
125         int index;
126
127         if (unlikely(ftrace_graph_is_dead()))
128                 return -EBUSY;
129
130         if (!current->ret_stack)
131                 return -EBUSY;
132
133         /*
134          * We must make sure the ret_stack is tested before we read
135          * anything else.
136          */
137         smp_rmb();
138
139         /* The return trace stack is full */
140         if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
141                 atomic_inc(&current->trace_overrun);
142                 return -EBUSY;
143         }
144
145         /*
146          * The curr_ret_stack is an index to ftrace return stack of
147          * current task.  Its value should be in [0, FTRACE_RETFUNC_
148          * DEPTH) when the function graph tracer is used.  To support
149          * filtering out specific functions, it makes the index
150          * negative by subtracting huge value (FTRACE_NOTRACE_DEPTH)
151          * so when it sees a negative index the ftrace will ignore
152          * the record.  And the index gets recovered when returning
153          * from the filtered function by adding the FTRACE_NOTRACE_
154          * DEPTH and then it'll continue to record functions normally.
155          *
156          * The curr_ret_stack is initialized to -1 and get increased
157          * in this function.  So it can be less than -1 only if it was
158          * filtered out via ftrace_graph_notrace_addr() which can be
159          * set from set_graph_notrace file in tracefs by user.
160          */
161         if (current->curr_ret_stack < -1)
162                 return -EBUSY;
163
164         calltime = trace_clock_local();
165
166         index = ++current->curr_ret_stack;
167         if (ftrace_graph_notrace_addr(func))
168                 current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH;
169         barrier();
170         current->ret_stack[index].ret = ret;
171         current->ret_stack[index].func = func;
172         current->ret_stack[index].calltime = calltime;
173 #ifdef HAVE_FUNCTION_GRAPH_FP_TEST
174         current->ret_stack[index].fp = frame_pointer;
175 #endif
176 #ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
177         current->ret_stack[index].retp = retp;
178 #endif
179         *depth = current->curr_ret_stack;
180
181         return 0;
182 }
183
184 /* Retrieve a function return address to the trace stack on thread info.*/
185 static void
186 ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
187                         unsigned long frame_pointer)
188 {
189         int index;
190
191         index = current->curr_ret_stack;
192
193         /*
194          * A negative index here means that it's just returned from a
195          * notrace'd function.  Recover index to get an original
196          * return address.  See ftrace_push_return_trace().
197          *
198          * TODO: Need to check whether the stack gets corrupted.
199          */
200         if (index < 0)
201                 index += FTRACE_NOTRACE_DEPTH;
202
203         if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) {
204                 ftrace_graph_stop();
205                 WARN_ON(1);
206                 /* Might as well panic, otherwise we have no where to go */
207                 *ret = (unsigned long)panic;
208                 return;
209         }
210
211 #ifdef HAVE_FUNCTION_GRAPH_FP_TEST
212         /*
213          * The arch may choose to record the frame pointer used
214          * and check it here to make sure that it is what we expect it
215          * to be. If gcc does not set the place holder of the return
216          * address in the frame pointer, and does a copy instead, then
217          * the function graph trace will fail. This test detects this
218          * case.
219          *
220          * Currently, x86_32 with optimize for size (-Os) makes the latest
221          * gcc do the above.
222          *
223          * Note, -mfentry does not use frame pointers, and this test
224          *  is not needed if CC_USING_FENTRY is set.
225          */
226         if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
227                 ftrace_graph_stop();
228                 WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
229                      "  from func %ps return to %lx\n",
230                      current->ret_stack[index].fp,
231                      frame_pointer,
232                      (void *)current->ret_stack[index].func,
233                      current->ret_stack[index].ret);
234                 *ret = (unsigned long)panic;
235                 return;
236         }
237 #endif
238
239         *ret = current->ret_stack[index].ret;
240         trace->func = current->ret_stack[index].func;
241         trace->calltime = current->ret_stack[index].calltime;
242         trace->overrun = atomic_read(&current->trace_overrun);
243         trace->depth = index;
244 }
245
246 /*
247  * Send the trace to the ring-buffer.
248  * @return the original return address.
249  */
250 unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
251 {
252         struct ftrace_graph_ret trace;
253         unsigned long ret;
254
255         ftrace_pop_return_trace(&trace, &ret, frame_pointer);
256         trace.rettime = trace_clock_local();
257         barrier();
258         current->curr_ret_stack--;
259         /*
260          * The curr_ret_stack can be less than -1 only if it was
261          * filtered out and it's about to return from the function.
262          * Recover the index and continue to trace normal functions.
263          */
264         if (current->curr_ret_stack < -1) {
265                 current->curr_ret_stack += FTRACE_NOTRACE_DEPTH;
266                 return ret;
267         }
268
269         /*
270          * The trace should run after decrementing the ret counter
271          * in case an interrupt were to come in. We don't want to
272          * lose the interrupt if max_depth is set.
273          */
274         ftrace_graph_return(&trace);
275
276         if (unlikely(!ret)) {
277                 ftrace_graph_stop();
278                 WARN_ON(1);
279                 /* Might as well panic. What else to do? */
280                 ret = (unsigned long)panic;
281         }
282
283         return ret;
284 }
285
286 /**
287  * ftrace_graph_ret_addr - convert a potentially modified stack return address
288  *                         to its original value
289  *
290  * This function can be called by stack unwinding code to convert a found stack
291  * return address ('ret') to its original value, in case the function graph
292  * tracer has modified it to be 'return_to_handler'.  If the address hasn't
293  * been modified, the unchanged value of 'ret' is returned.
294  *
295  * 'idx' is a state variable which should be initialized by the caller to zero
296  * before the first call.
297  *
298  * 'retp' is a pointer to the return address on the stack.  It's ignored if
299  * the arch doesn't have HAVE_FUNCTION_GRAPH_RET_ADDR_PTR defined.
300  */
301 #ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
302 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
303                                     unsigned long ret, unsigned long *retp)
304 {
305         int index = task->curr_ret_stack;
306         int i;
307
308         if (ret != (unsigned long)return_to_handler)
309                 return ret;
310
311         if (index < -1)
312                 index += FTRACE_NOTRACE_DEPTH;
313
314         if (index < 0)
315                 return ret;
316
317         for (i = 0; i <= index; i++)
318                 if (task->ret_stack[i].retp == retp)
319                         return task->ret_stack[i].ret;
320
321         return ret;
322 }
323 #else /* !HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */
324 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
325                                     unsigned long ret, unsigned long *retp)
326 {
327         int task_idx;
328
329         if (ret != (unsigned long)return_to_handler)
330                 return ret;
331
332         task_idx = task->curr_ret_stack;
333
334         if (!task->ret_stack || task_idx < *idx)
335                 return ret;
336
337         task_idx -= *idx;
338         (*idx)++;
339
340         return task->ret_stack[task_idx].ret;
341 }
342 #endif /* HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */
343
344 int __trace_graph_entry(struct trace_array *tr,
345                                 struct ftrace_graph_ent *trace,
346                                 unsigned long flags,
347                                 int pc)
348 {
349         struct trace_event_call *call = &event_funcgraph_entry;
350         struct ring_buffer_event *event;
351         struct ring_buffer *buffer = tr->trace_buffer.buffer;
352         struct ftrace_graph_ent_entry *entry;
353
354         event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
355                                           sizeof(*entry), flags, pc);
356         if (!event)
357                 return 0;
358         entry   = ring_buffer_event_data(event);
359         entry->graph_ent                        = *trace;
360         if (!call_filter_check_discard(call, entry, buffer, event))
361                 __buffer_unlock_commit(buffer, event);
362
363         return 1;
364 }
365
366 static inline int ftrace_graph_ignore_irqs(void)
367 {
368         if (!ftrace_graph_skip_irqs || trace_recursion_test(TRACE_IRQ_BIT))
369                 return 0;
370
371         return in_irq();
372 }
373
374 int trace_graph_entry(struct ftrace_graph_ent *trace)
375 {
376         struct trace_array *tr = graph_array;
377         struct trace_array_cpu *data;
378         unsigned long flags;
379         long disabled;
380         int ret;
381         int cpu;
382         int pc;
383
384         if (!ftrace_trace_task(tr))
385                 return 0;
386
387         /* trace it when it is-nested-in or is a function enabled. */
388         if ((!(trace->depth || ftrace_graph_addr(trace->func)) ||
389              ftrace_graph_ignore_irqs()) || (trace->depth < 0) ||
390             (max_depth && trace->depth >= max_depth))
391                 return 0;
392
393         /*
394          * Do not trace a function if it's filtered by set_graph_notrace.
395          * Make the index of ret stack negative to indicate that it should
396          * ignore further functions.  But it needs its own ret stack entry
397          * to recover the original index in order to continue tracing after
398          * returning from the function.
399          */
400         if (ftrace_graph_notrace_addr(trace->func))
401                 return 1;
402
403         /*
404          * Stop here if tracing_threshold is set. We only write function return
405          * events to the ring buffer.
406          */
407         if (tracing_thresh)
408                 return 1;
409
410         local_irq_save(flags);
411         cpu = raw_smp_processor_id();
412         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
413         disabled = atomic_inc_return(&data->disabled);
414         if (likely(disabled == 1)) {
415                 pc = preempt_count();
416                 ret = __trace_graph_entry(tr, trace, flags, pc);
417         } else {
418                 ret = 0;
419         }
420
421         atomic_dec(&data->disabled);
422         local_irq_restore(flags);
423
424         return ret;
425 }
426
427 static void
428 __trace_graph_function(struct trace_array *tr,
429                 unsigned long ip, unsigned long flags, int pc)
430 {
431         u64 time = trace_clock_local();
432         struct ftrace_graph_ent ent = {
433                 .func  = ip,
434                 .depth = 0,
435         };
436         struct ftrace_graph_ret ret = {
437                 .func     = ip,
438                 .depth    = 0,
439                 .calltime = time,
440                 .rettime  = time,
441         };
442
443         __trace_graph_entry(tr, &ent, flags, pc);
444         __trace_graph_return(tr, &ret, flags, pc);
445 }
446
447 void
448 trace_graph_function(struct trace_array *tr,
449                 unsigned long ip, unsigned long parent_ip,
450                 unsigned long flags, int pc)
451 {
452         __trace_graph_function(tr, ip, flags, pc);
453 }
454
455 void __trace_graph_return(struct trace_array *tr,
456                                 struct ftrace_graph_ret *trace,
457                                 unsigned long flags,
458                                 int pc)
459 {
460         struct trace_event_call *call = &event_funcgraph_exit;
461         struct ring_buffer_event *event;
462         struct ring_buffer *buffer = tr->trace_buffer.buffer;
463         struct ftrace_graph_ret_entry *entry;
464
465         event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
466                                           sizeof(*entry), flags, pc);
467         if (!event)
468                 return;
469         entry   = ring_buffer_event_data(event);
470         entry->ret                              = *trace;
471         if (!call_filter_check_discard(call, entry, buffer, event))
472                 __buffer_unlock_commit(buffer, event);
473 }
474
475 void trace_graph_return(struct ftrace_graph_ret *trace)
476 {
477         struct trace_array *tr = graph_array;
478         struct trace_array_cpu *data;
479         unsigned long flags;
480         long disabled;
481         int cpu;
482         int pc;
483
484         local_irq_save(flags);
485         cpu = raw_smp_processor_id();
486         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
487         disabled = atomic_inc_return(&data->disabled);
488         if (likely(disabled == 1)) {
489                 pc = preempt_count();
490                 __trace_graph_return(tr, trace, flags, pc);
491         }
492         atomic_dec(&data->disabled);
493         local_irq_restore(flags);
494 }
495
496 void set_graph_array(struct trace_array *tr)
497 {
498         graph_array = tr;
499
500         /* Make graph_array visible before we start tracing */
501
502         smp_mb();
503 }
504
505 static void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
506 {
507         if (tracing_thresh &&
508             (trace->rettime - trace->calltime < tracing_thresh))
509                 return;
510         else
511                 trace_graph_return(trace);
512 }
513
514 static int graph_trace_init(struct trace_array *tr)
515 {
516         int ret;
517
518         set_graph_array(tr);
519         if (tracing_thresh)
520                 ret = register_ftrace_graph(&trace_graph_thresh_return,
521                                             &trace_graph_entry);
522         else
523                 ret = register_ftrace_graph(&trace_graph_return,
524                                             &trace_graph_entry);
525         if (ret)
526                 return ret;
527         tracing_start_cmdline_record();
528
529         return 0;
530 }
531
532 static void graph_trace_reset(struct trace_array *tr)
533 {
534         tracing_stop_cmdline_record();
535         unregister_ftrace_graph();
536 }
537
538 static int graph_trace_update_thresh(struct trace_array *tr)
539 {
540         graph_trace_reset(tr);
541         return graph_trace_init(tr);
542 }
543
544 static int max_bytes_for_cpu;
545
546 static void print_graph_cpu(struct trace_seq *s, int cpu)
547 {
548         /*
549          * Start with a space character - to make it stand out
550          * to the right a bit when trace output is pasted into
551          * email:
552          */
553         trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
554 }
555
556 #define TRACE_GRAPH_PROCINFO_LENGTH     14
557
558 static void print_graph_proc(struct trace_seq *s, pid_t pid)
559 {
560         char comm[TASK_COMM_LEN];
561         /* sign + log10(MAX_INT) + '\0' */
562         char pid_str[11];
563         int spaces = 0;
564         int len;
565         int i;
566
567         trace_find_cmdline(pid, comm);
568         comm[7] = '\0';
569         sprintf(pid_str, "%d", pid);
570
571         /* 1 stands for the "-" character */
572         len = strlen(comm) + strlen(pid_str) + 1;
573
574         if (len < TRACE_GRAPH_PROCINFO_LENGTH)
575                 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
576
577         /* First spaces to align center */
578         for (i = 0; i < spaces / 2; i++)
579                 trace_seq_putc(s, ' ');
580
581         trace_seq_printf(s, "%s-%s", comm, pid_str);
582
583         /* Last spaces to align center */
584         for (i = 0; i < spaces - (spaces / 2); i++)
585                 trace_seq_putc(s, ' ');
586 }
587
588
589 static void print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
590 {
591         trace_seq_putc(s, ' ');
592         trace_print_lat_fmt(s, entry);
593 }
594
595 /* If the pid changed since the last trace, output this event */
596 static void
597 verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
598 {
599         pid_t prev_pid;
600         pid_t *last_pid;
601
602         if (!data)
603                 return;
604
605         last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
606
607         if (*last_pid == pid)
608                 return;
609
610         prev_pid = *last_pid;
611         *last_pid = pid;
612
613         if (prev_pid == -1)
614                 return;
615 /*
616  * Context-switch trace line:
617
618  ------------------------------------------
619  | 1)  migration/0--1  =>  sshd-1755
620  ------------------------------------------
621
622  */
623         trace_seq_puts(s, " ------------------------------------------\n");
624         print_graph_cpu(s, cpu);
625         print_graph_proc(s, prev_pid);
626         trace_seq_puts(s, " => ");
627         print_graph_proc(s, pid);
628         trace_seq_puts(s, "\n ------------------------------------------\n\n");
629 }
630
631 static struct ftrace_graph_ret_entry *
632 get_return_for_leaf(struct trace_iterator *iter,
633                 struct ftrace_graph_ent_entry *curr)
634 {
635         struct fgraph_data *data = iter->private;
636         struct ring_buffer_iter *ring_iter = NULL;
637         struct ring_buffer_event *event;
638         struct ftrace_graph_ret_entry *next;
639
640         /*
641          * If the previous output failed to write to the seq buffer,
642          * then we just reuse the data from before.
643          */
644         if (data && data->failed) {
645                 curr = &data->ent;
646                 next = &data->ret;
647         } else {
648
649                 ring_iter = trace_buffer_iter(iter, iter->cpu);
650
651                 /* First peek to compare current entry and the next one */
652                 if (ring_iter)
653                         event = ring_buffer_iter_peek(ring_iter, NULL);
654                 else {
655                         /*
656                          * We need to consume the current entry to see
657                          * the next one.
658                          */
659                         ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu,
660                                             NULL, NULL);
661                         event = ring_buffer_peek(iter->trace_buffer->buffer, iter->cpu,
662                                                  NULL, NULL);
663                 }
664
665                 if (!event)
666                         return NULL;
667
668                 next = ring_buffer_event_data(event);
669
670                 if (data) {
671                         /*
672                          * Save current and next entries for later reference
673                          * if the output fails.
674                          */
675                         data->ent = *curr;
676                         /*
677                          * If the next event is not a return type, then
678                          * we only care about what type it is. Otherwise we can
679                          * safely copy the entire event.
680                          */
681                         if (next->ent.type == TRACE_GRAPH_RET)
682                                 data->ret = *next;
683                         else
684                                 data->ret.ent.type = next->ent.type;
685                 }
686         }
687
688         if (next->ent.type != TRACE_GRAPH_RET)
689                 return NULL;
690
691         if (curr->ent.pid != next->ent.pid ||
692                         curr->graph_ent.func != next->ret.func)
693                 return NULL;
694
695         /* this is a leaf, now advance the iterator */
696         if (ring_iter)
697                 ring_buffer_read(ring_iter, NULL);
698
699         return next;
700 }
701
702 static void print_graph_abs_time(u64 t, struct trace_seq *s)
703 {
704         unsigned long usecs_rem;
705
706         usecs_rem = do_div(t, NSEC_PER_SEC);
707         usecs_rem /= 1000;
708
709         trace_seq_printf(s, "%5lu.%06lu |  ",
710                          (unsigned long)t, usecs_rem);
711 }
712
713 static void
714 print_graph_irq(struct trace_iterator *iter, unsigned long addr,
715                 enum trace_type type, int cpu, pid_t pid, u32 flags)
716 {
717         struct trace_array *tr = iter->tr;
718         struct trace_seq *s = &iter->seq;
719         struct trace_entry *ent = iter->ent;
720
721         if (addr < (unsigned long)__irqentry_text_start ||
722                 addr >= (unsigned long)__irqentry_text_end)
723                 return;
724
725         if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
726                 /* Absolute time */
727                 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
728                         print_graph_abs_time(iter->ts, s);
729
730                 /* Cpu */
731                 if (flags & TRACE_GRAPH_PRINT_CPU)
732                         print_graph_cpu(s, cpu);
733
734                 /* Proc */
735                 if (flags & TRACE_GRAPH_PRINT_PROC) {
736                         print_graph_proc(s, pid);
737                         trace_seq_puts(s, " | ");
738                 }
739
740                 /* Latency format */
741                 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
742                         print_graph_lat_fmt(s, ent);
743         }
744
745         /* No overhead */
746         print_graph_duration(tr, 0, s, flags | FLAGS_FILL_START);
747
748         if (type == TRACE_GRAPH_ENT)
749                 trace_seq_puts(s, "==========>");
750         else
751                 trace_seq_puts(s, "<==========");
752
753         print_graph_duration(tr, 0, s, flags | FLAGS_FILL_END);
754         trace_seq_putc(s, '\n');
755 }
756
757 void
758 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
759 {
760         unsigned long nsecs_rem = do_div(duration, 1000);
761         /* log10(ULONG_MAX) + '\0' */
762         char usecs_str[21];
763         char nsecs_str[5];
764         int len;
765         int i;
766
767         sprintf(usecs_str, "%lu", (unsigned long) duration);
768
769         /* Print msecs */
770         trace_seq_printf(s, "%s", usecs_str);
771
772         len = strlen(usecs_str);
773
774         /* Print nsecs (we don't want to exceed 7 numbers) */
775         if (len < 7) {
776                 size_t slen = min_t(size_t, sizeof(nsecs_str), 8UL - len);
777
778                 snprintf(nsecs_str, slen, "%03lu", nsecs_rem);
779                 trace_seq_printf(s, ".%s", nsecs_str);
780                 len += strlen(nsecs_str) + 1;
781         }
782
783         trace_seq_puts(s, " us ");
784
785         /* Print remaining spaces to fit the row's width */
786         for (i = len; i < 8; i++)
787                 trace_seq_putc(s, ' ');
788 }
789
790 static void
791 print_graph_duration(struct trace_array *tr, unsigned long long duration,
792                      struct trace_seq *s, u32 flags)
793 {
794         if (!(flags & TRACE_GRAPH_PRINT_DURATION) ||
795             !(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
796                 return;
797
798         /* No real adata, just filling the column with spaces */
799         switch (flags & TRACE_GRAPH_PRINT_FILL_MASK) {
800         case FLAGS_FILL_FULL:
801                 trace_seq_puts(s, "              |  ");
802                 return;
803         case FLAGS_FILL_START:
804                 trace_seq_puts(s, "  ");
805                 return;
806         case FLAGS_FILL_END:
807                 trace_seq_puts(s, " |");
808                 return;
809         }
810
811         /* Signal a overhead of time execution to the output */
812         if (flags & TRACE_GRAPH_PRINT_OVERHEAD)
813                 trace_seq_printf(s, "%c ", trace_find_mark(duration));
814         else
815                 trace_seq_puts(s, "  ");
816
817         trace_print_graph_duration(duration, s);
818         trace_seq_puts(s, "|  ");
819 }
820
821 /* Case of a leaf function on its call entry */
822 static enum print_line_t
823 print_graph_entry_leaf(struct trace_iterator *iter,
824                 struct ftrace_graph_ent_entry *entry,
825                 struct ftrace_graph_ret_entry *ret_entry,
826                 struct trace_seq *s, u32 flags)
827 {
828         struct fgraph_data *data = iter->private;
829         struct trace_array *tr = iter->tr;
830         struct ftrace_graph_ret *graph_ret;
831         struct ftrace_graph_ent *call;
832         unsigned long long duration;
833         int cpu = iter->cpu;
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
843                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
844
845                 /* If a graph tracer ignored set_graph_notrace */
846                 if (call->depth < -1)
847                         call->depth += FTRACE_NOTRACE_DEPTH;
848
849                 /*
850                  * Comments display at + 1 to depth. Since
851                  * this is a leaf function, keep the comments
852                  * equal to this depth.
853                  */
854                 cpu_data->depth = call->depth - 1;
855
856                 /* No need to keep this function around for this depth */
857                 if (call->depth < FTRACE_RETFUNC_DEPTH &&
858                     !WARN_ON_ONCE(call->depth < 0))
859                         cpu_data->enter_funcs[call->depth] = 0;
860         }
861
862         /* Overhead and duration */
863         print_graph_duration(tr, duration, s, flags);
864
865         /* Function */
866         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
867                 trace_seq_putc(s, ' ');
868
869         trace_seq_printf(s, "%ps();\n", (void *)call->func);
870
871         print_graph_irq(iter, graph_ret->func, TRACE_GRAPH_RET,
872                         cpu, iter->ent->pid, flags);
873
874         return trace_handle_return(s);
875 }
876
877 static enum print_line_t
878 print_graph_entry_nested(struct trace_iterator *iter,
879                          struct ftrace_graph_ent_entry *entry,
880                          struct trace_seq *s, int cpu, u32 flags)
881 {
882         struct ftrace_graph_ent *call = &entry->graph_ent;
883         struct fgraph_data *data = iter->private;
884         struct trace_array *tr = iter->tr;
885         int i;
886
887         if (data) {
888                 struct fgraph_cpu_data *cpu_data;
889                 int cpu = iter->cpu;
890
891                 /* If a graph tracer ignored set_graph_notrace */
892                 if (call->depth < -1)
893                         call->depth += FTRACE_NOTRACE_DEPTH;
894
895                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
896                 cpu_data->depth = call->depth;
897
898                 /* Save this function pointer to see if the exit matches */
899                 if (call->depth < FTRACE_RETFUNC_DEPTH &&
900                     !WARN_ON_ONCE(call->depth < 0))
901                         cpu_data->enter_funcs[call->depth] = call->func;
902         }
903
904         /* No time */
905         print_graph_duration(tr, 0, s, flags | FLAGS_FILL_FULL);
906
907         /* Function */
908         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
909                 trace_seq_putc(s, ' ');
910
911         trace_seq_printf(s, "%ps() {\n", (void *)call->func);
912
913         if (trace_seq_has_overflowed(s))
914                 return TRACE_TYPE_PARTIAL_LINE;
915
916         /*
917          * we already consumed the current entry to check the next one
918          * and see if this is a leaf.
919          */
920         return TRACE_TYPE_NO_CONSUME;
921 }
922
923 static void
924 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
925                      int type, unsigned long addr, u32 flags)
926 {
927         struct fgraph_data *data = iter->private;
928         struct trace_entry *ent = iter->ent;
929         struct trace_array *tr = iter->tr;
930         int cpu = iter->cpu;
931
932         /* Pid */
933         verif_pid(s, ent->pid, cpu, data);
934
935         if (type)
936                 /* Interrupt */
937                 print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
938
939         if (!(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
940                 return;
941
942         /* Absolute time */
943         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
944                 print_graph_abs_time(iter->ts, s);
945
946         /* Cpu */
947         if (flags & TRACE_GRAPH_PRINT_CPU)
948                 print_graph_cpu(s, cpu);
949
950         /* Proc */
951         if (flags & TRACE_GRAPH_PRINT_PROC) {
952                 print_graph_proc(s, ent->pid);
953                 trace_seq_puts(s, " | ");
954         }
955
956         /* Latency format */
957         if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
958                 print_graph_lat_fmt(s, ent);
959
960         return;
961 }
962
963 /*
964  * Entry check for irq code
965  *
966  * returns 1 if
967  *  - we are inside irq code
968  *  - we just entered irq code
969  *
970  * retunns 0 if
971  *  - funcgraph-interrupts option is set
972  *  - we are not inside irq code
973  */
974 static int
975 check_irq_entry(struct trace_iterator *iter, u32 flags,
976                 unsigned long addr, int depth)
977 {
978         int cpu = iter->cpu;
979         int *depth_irq;
980         struct fgraph_data *data = iter->private;
981
982         /*
983          * If we are either displaying irqs, or we got called as
984          * a graph event and private data does not exist,
985          * then we bypass the irq check.
986          */
987         if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
988             (!data))
989                 return 0;
990
991         depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
992
993         /*
994          * We are inside the irq code
995          */
996         if (*depth_irq >= 0)
997                 return 1;
998
999         if ((addr < (unsigned long)__irqentry_text_start) ||
1000             (addr >= (unsigned long)__irqentry_text_end))
1001                 return 0;
1002
1003         /*
1004          * We are entering irq code.
1005          */
1006         *depth_irq = depth;
1007         return 1;
1008 }
1009
1010 /*
1011  * Return check for irq code
1012  *
1013  * returns 1 if
1014  *  - we are inside irq code
1015  *  - we just left irq code
1016  *
1017  * returns 0 if
1018  *  - funcgraph-interrupts option is set
1019  *  - we are not inside irq code
1020  */
1021 static int
1022 check_irq_return(struct trace_iterator *iter, u32 flags, int depth)
1023 {
1024         int cpu = iter->cpu;
1025         int *depth_irq;
1026         struct fgraph_data *data = iter->private;
1027
1028         /*
1029          * If we are either displaying irqs, or we got called as
1030          * a graph event and private data does not exist,
1031          * then we bypass the irq check.
1032          */
1033         if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
1034             (!data))
1035                 return 0;
1036
1037         depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1038
1039         /*
1040          * We are not inside the irq code.
1041          */
1042         if (*depth_irq == -1)
1043                 return 0;
1044
1045         /*
1046          * We are inside the irq code, and this is returning entry.
1047          * Let's not trace it and clear the entry depth, since
1048          * we are out of irq code.
1049          *
1050          * This condition ensures that we 'leave the irq code' once
1051          * we are out of the entry depth. Thus protecting us from
1052          * the RETURN entry loss.
1053          */
1054         if (*depth_irq >= depth) {
1055                 *depth_irq = -1;
1056                 return 1;
1057         }
1058
1059         /*
1060          * We are inside the irq code, and this is not the entry.
1061          */
1062         return 1;
1063 }
1064
1065 static enum print_line_t
1066 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
1067                         struct trace_iterator *iter, u32 flags)
1068 {
1069         struct fgraph_data *data = iter->private;
1070         struct ftrace_graph_ent *call = &field->graph_ent;
1071         struct ftrace_graph_ret_entry *leaf_ret;
1072         static enum print_line_t ret;
1073         int cpu = iter->cpu;
1074
1075         if (check_irq_entry(iter, flags, call->func, call->depth))
1076                 return TRACE_TYPE_HANDLED;
1077
1078         print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags);
1079
1080         leaf_ret = get_return_for_leaf(iter, field);
1081         if (leaf_ret)
1082                 ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags);
1083         else
1084                 ret = print_graph_entry_nested(iter, field, s, cpu, flags);
1085
1086         if (data) {
1087                 /*
1088                  * If we failed to write our output, then we need to make
1089                  * note of it. Because we already consumed our entry.
1090                  */
1091                 if (s->full) {
1092                         data->failed = 1;
1093                         data->cpu = cpu;
1094                 } else
1095                         data->failed = 0;
1096         }
1097
1098         return ret;
1099 }
1100
1101 static enum print_line_t
1102 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
1103                    struct trace_entry *ent, struct trace_iterator *iter,
1104                    u32 flags)
1105 {
1106         unsigned long long duration = trace->rettime - trace->calltime;
1107         struct fgraph_data *data = iter->private;
1108         struct trace_array *tr = iter->tr;
1109         pid_t pid = ent->pid;
1110         int cpu = iter->cpu;
1111         int func_match = 1;
1112         int i;
1113
1114         if (check_irq_return(iter, flags, trace->depth))
1115                 return TRACE_TYPE_HANDLED;
1116
1117         if (data) {
1118                 struct fgraph_cpu_data *cpu_data;
1119                 int cpu = iter->cpu;
1120
1121                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
1122
1123                 /*
1124                  * Comments display at + 1 to depth. This is the
1125                  * return from a function, we now want the comments
1126                  * to display at the same level of the bracket.
1127                  */
1128                 cpu_data->depth = trace->depth - 1;
1129
1130                 if (trace->depth < FTRACE_RETFUNC_DEPTH &&
1131                     !WARN_ON_ONCE(trace->depth < 0)) {
1132                         if (cpu_data->enter_funcs[trace->depth] != trace->func)
1133                                 func_match = 0;
1134                         cpu_data->enter_funcs[trace->depth] = 0;
1135                 }
1136         }
1137
1138         print_graph_prologue(iter, s, 0, 0, flags);
1139
1140         /* Overhead and duration */
1141         print_graph_duration(tr, duration, s, flags);
1142
1143         /* Closing brace */
1144         for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++)
1145                 trace_seq_putc(s, ' ');
1146
1147         /*
1148          * If the return function does not have a matching entry,
1149          * then the entry was lost. Instead of just printing
1150          * the '}' and letting the user guess what function this
1151          * belongs to, write out the function name. Always do
1152          * that if the funcgraph-tail option is enabled.
1153          */
1154         if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL))
1155                 trace_seq_puts(s, "}\n");
1156         else
1157                 trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
1158
1159         /* Overrun */
1160         if (flags & TRACE_GRAPH_PRINT_OVERRUN)
1161                 trace_seq_printf(s, " (Overruns: %lu)\n",
1162                                  trace->overrun);
1163
1164         print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
1165                         cpu, pid, flags);
1166
1167         return trace_handle_return(s);
1168 }
1169
1170 static enum print_line_t
1171 print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
1172                     struct trace_iterator *iter, u32 flags)
1173 {
1174         struct trace_array *tr = iter->tr;
1175         unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
1176         struct fgraph_data *data = iter->private;
1177         struct trace_event *event;
1178         int depth = 0;
1179         int ret;
1180         int i;
1181
1182         if (data)
1183                 depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
1184
1185         print_graph_prologue(iter, s, 0, 0, flags);
1186
1187         /* No time */
1188         print_graph_duration(tr, 0, s, flags | FLAGS_FILL_FULL);
1189
1190         /* Indentation */
1191         if (depth > 0)
1192                 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++)
1193                         trace_seq_putc(s, ' ');
1194
1195         /* The comment */
1196         trace_seq_puts(s, "/* ");
1197
1198         switch (iter->ent->type) {
1199         case TRACE_BPUTS:
1200                 ret = trace_print_bputs_msg_only(iter);
1201                 if (ret != TRACE_TYPE_HANDLED)
1202                         return ret;
1203                 break;
1204         case TRACE_BPRINT:
1205                 ret = trace_print_bprintk_msg_only(iter);
1206                 if (ret != TRACE_TYPE_HANDLED)
1207                         return ret;
1208                 break;
1209         case TRACE_PRINT:
1210                 ret = trace_print_printk_msg_only(iter);
1211                 if (ret != TRACE_TYPE_HANDLED)
1212                         return ret;
1213                 break;
1214         default:
1215                 event = ftrace_find_event(ent->type);
1216                 if (!event)
1217                         return TRACE_TYPE_UNHANDLED;
1218
1219                 ret = event->funcs->trace(iter, sym_flags, event);
1220                 if (ret != TRACE_TYPE_HANDLED)
1221                         return ret;
1222         }
1223
1224         if (trace_seq_has_overflowed(s))
1225                 goto out;
1226
1227         /* Strip ending newline */
1228         if (s->buffer[s->seq.len - 1] == '\n') {
1229                 s->buffer[s->seq.len - 1] = '\0';
1230                 s->seq.len--;
1231         }
1232
1233         trace_seq_puts(s, " */\n");
1234  out:
1235         return trace_handle_return(s);
1236 }
1237
1238
1239 enum print_line_t
1240 print_graph_function_flags(struct trace_iterator *iter, u32 flags)
1241 {
1242         struct ftrace_graph_ent_entry *field;
1243         struct fgraph_data *data = iter->private;
1244         struct trace_entry *entry = iter->ent;
1245         struct trace_seq *s = &iter->seq;
1246         int cpu = iter->cpu;
1247         int ret;
1248
1249         if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
1250                 per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
1251                 return TRACE_TYPE_HANDLED;
1252         }
1253
1254         /*
1255          * If the last output failed, there's a possibility we need
1256          * to print out the missing entry which would never go out.
1257          */
1258         if (data && data->failed) {
1259                 field = &data->ent;
1260                 iter->cpu = data->cpu;
1261                 ret = print_graph_entry(field, s, iter, flags);
1262                 if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
1263                         per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
1264                         ret = TRACE_TYPE_NO_CONSUME;
1265                 }
1266                 iter->cpu = cpu;
1267                 return ret;
1268         }
1269
1270         switch (entry->type) {
1271         case TRACE_GRAPH_ENT: {
1272                 /*
1273                  * print_graph_entry() may consume the current event,
1274                  * thus @field may become invalid, so we need to save it.
1275                  * sizeof(struct ftrace_graph_ent_entry) is very small,
1276                  * it can be safely saved at the stack.
1277                  */
1278                 struct ftrace_graph_ent_entry saved;
1279                 trace_assign_type(field, entry);
1280                 saved = *field;
1281                 return print_graph_entry(&saved, s, iter, flags);
1282         }
1283         case TRACE_GRAPH_RET: {
1284                 struct ftrace_graph_ret_entry *field;
1285                 trace_assign_type(field, entry);
1286                 return print_graph_return(&field->ret, s, entry, iter, flags);
1287         }
1288         case TRACE_STACK:
1289         case TRACE_FN:
1290                 /* dont trace stack and functions as comments */
1291                 return TRACE_TYPE_UNHANDLED;
1292
1293         default:
1294                 return print_graph_comment(s, entry, iter, flags);
1295         }
1296
1297         return TRACE_TYPE_HANDLED;
1298 }
1299
1300 static enum print_line_t
1301 print_graph_function(struct trace_iterator *iter)
1302 {
1303         return print_graph_function_flags(iter, tracer_flags.val);
1304 }
1305
1306 static enum print_line_t
1307 print_graph_function_event(struct trace_iterator *iter, int flags,
1308                            struct trace_event *event)
1309 {
1310         return print_graph_function(iter);
1311 }
1312
1313 static void print_lat_header(struct seq_file *s, u32 flags)
1314 {
1315         static const char spaces[] = "                " /* 16 spaces */
1316                 "    "                                  /* 4 spaces */
1317                 "                 ";                    /* 17 spaces */
1318         int size = 0;
1319
1320         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1321                 size += 16;
1322         if (flags & TRACE_GRAPH_PRINT_CPU)
1323                 size += 4;
1324         if (flags & TRACE_GRAPH_PRINT_PROC)
1325                 size += 17;
1326
1327         seq_printf(s, "#%.*s  _-----=> irqs-off        \n", size, spaces);
1328         seq_printf(s, "#%.*s / _----=> need-resched    \n", size, spaces);
1329         seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
1330         seq_printf(s, "#%.*s|| / _--=> preempt-depth   \n", size, spaces);
1331         seq_printf(s, "#%.*s||| /                      \n", size, spaces);
1332 }
1333
1334 static void __print_graph_headers_flags(struct trace_array *tr,
1335                                         struct seq_file *s, u32 flags)
1336 {
1337         int lat = tr->trace_flags & TRACE_ITER_LATENCY_FMT;
1338
1339         if (lat)
1340                 print_lat_header(s, flags);
1341
1342         /* 1st line */
1343         seq_putc(s, '#');
1344         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1345                 seq_puts(s, "     TIME       ");
1346         if (flags & TRACE_GRAPH_PRINT_CPU)
1347                 seq_puts(s, " CPU");
1348         if (flags & TRACE_GRAPH_PRINT_PROC)
1349                 seq_puts(s, "  TASK/PID       ");
1350         if (lat)
1351                 seq_puts(s, "||||");
1352         if (flags & TRACE_GRAPH_PRINT_DURATION)
1353                 seq_puts(s, "  DURATION   ");
1354         seq_puts(s, "               FUNCTION CALLS\n");
1355
1356         /* 2nd line */
1357         seq_putc(s, '#');
1358         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1359                 seq_puts(s, "      |         ");
1360         if (flags & TRACE_GRAPH_PRINT_CPU)
1361                 seq_puts(s, " |  ");
1362         if (flags & TRACE_GRAPH_PRINT_PROC)
1363                 seq_puts(s, "   |    |        ");
1364         if (lat)
1365                 seq_puts(s, "||||");
1366         if (flags & TRACE_GRAPH_PRINT_DURATION)
1367                 seq_puts(s, "   |   |      ");
1368         seq_puts(s, "               |   |   |   |\n");
1369 }
1370
1371 static void print_graph_headers(struct seq_file *s)
1372 {
1373         print_graph_headers_flags(s, tracer_flags.val);
1374 }
1375
1376 void print_graph_headers_flags(struct seq_file *s, u32 flags)
1377 {
1378         struct trace_iterator *iter = s->private;
1379         struct trace_array *tr = iter->tr;
1380
1381         if (!(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
1382                 return;
1383
1384         if (tr->trace_flags & TRACE_ITER_LATENCY_FMT) {
1385                 /* print nothing if the buffers are empty */
1386                 if (trace_empty(iter))
1387                         return;
1388
1389                 print_trace_header(s, iter);
1390         }
1391
1392         __print_graph_headers_flags(tr, s, flags);
1393 }
1394
1395 void graph_trace_open(struct trace_iterator *iter)
1396 {
1397         /* pid and depth on the last trace processed */
1398         struct fgraph_data *data;
1399         gfp_t gfpflags;
1400         int cpu;
1401
1402         iter->private = NULL;
1403
1404         /* We can be called in atomic context via ftrace_dump() */
1405         gfpflags = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL;
1406
1407         data = kzalloc(sizeof(*data), gfpflags);
1408         if (!data)
1409                 goto out_err;
1410
1411         data->cpu_data = alloc_percpu_gfp(struct fgraph_cpu_data, gfpflags);
1412         if (!data->cpu_data)
1413                 goto out_err_free;
1414
1415         for_each_possible_cpu(cpu) {
1416                 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
1417                 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
1418                 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
1419                 int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1420
1421                 *pid = -1;
1422                 *depth = 0;
1423                 *ignore = 0;
1424                 *depth_irq = -1;
1425         }
1426
1427         iter->private = data;
1428
1429         return;
1430
1431  out_err_free:
1432         kfree(data);
1433  out_err:
1434         pr_warn("function graph tracer: not enough memory\n");
1435 }
1436
1437 void graph_trace_close(struct trace_iterator *iter)
1438 {
1439         struct fgraph_data *data = iter->private;
1440
1441         if (data) {
1442                 free_percpu(data->cpu_data);
1443                 kfree(data);
1444         }
1445 }
1446
1447 static int
1448 func_graph_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1449 {
1450         if (bit == TRACE_GRAPH_PRINT_IRQS)
1451                 ftrace_graph_skip_irqs = !set;
1452
1453         if (bit == TRACE_GRAPH_SLEEP_TIME)
1454                 ftrace_graph_sleep_time_control(set);
1455
1456         if (bit == TRACE_GRAPH_GRAPH_TIME)
1457                 ftrace_graph_graph_time_control(set);
1458
1459         return 0;
1460 }
1461
1462 static struct trace_event_functions graph_functions = {
1463         .trace          = print_graph_function_event,
1464 };
1465
1466 static struct trace_event graph_trace_entry_event = {
1467         .type           = TRACE_GRAPH_ENT,
1468         .funcs          = &graph_functions,
1469 };
1470
1471 static struct trace_event graph_trace_ret_event = {
1472         .type           = TRACE_GRAPH_RET,
1473         .funcs          = &graph_functions
1474 };
1475
1476 static struct tracer graph_trace __tracer_data = {
1477         .name           = "function_graph",
1478         .update_thresh  = graph_trace_update_thresh,
1479         .open           = graph_trace_open,
1480         .pipe_open      = graph_trace_open,
1481         .close          = graph_trace_close,
1482         .pipe_close     = graph_trace_close,
1483         .init           = graph_trace_init,
1484         .reset          = graph_trace_reset,
1485         .print_line     = print_graph_function,
1486         .print_header   = print_graph_headers,
1487         .flags          = &tracer_flags,
1488         .set_flag       = func_graph_set_flag,
1489 #ifdef CONFIG_FTRACE_SELFTEST
1490         .selftest       = trace_selftest_startup_function_graph,
1491 #endif
1492 };
1493
1494
1495 static ssize_t
1496 graph_depth_write(struct file *filp, const char __user *ubuf, size_t cnt,
1497                   loff_t *ppos)
1498 {
1499         unsigned long val;
1500         int ret;
1501
1502         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1503         if (ret)
1504                 return ret;
1505
1506         max_depth = val;
1507
1508         *ppos += cnt;
1509
1510         return cnt;
1511 }
1512
1513 static ssize_t
1514 graph_depth_read(struct file *filp, char __user *ubuf, size_t cnt,
1515                  loff_t *ppos)
1516 {
1517         char buf[15]; /* More than enough to hold UINT_MAX + "\n"*/
1518         int n;
1519
1520         n = sprintf(buf, "%d\n", max_depth);
1521
1522         return simple_read_from_buffer(ubuf, cnt, ppos, buf, n);
1523 }
1524
1525 static const struct file_operations graph_depth_fops = {
1526         .open           = tracing_open_generic,
1527         .write          = graph_depth_write,
1528         .read           = graph_depth_read,
1529         .llseek         = generic_file_llseek,
1530 };
1531
1532 static __init int init_graph_tracefs(void)
1533 {
1534         struct dentry *d_tracer;
1535
1536         d_tracer = tracing_init_dentry();
1537         if (IS_ERR(d_tracer))
1538                 return 0;
1539
1540         trace_create_file("max_graph_depth", 0644, d_tracer,
1541                           NULL, &graph_depth_fops);
1542
1543         return 0;
1544 }
1545 fs_initcall(init_graph_tracefs);
1546
1547 static __init int init_graph_trace(void)
1548 {
1549         max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);
1550
1551         if (!register_trace_event(&graph_trace_entry_event)) {
1552                 pr_warn("Warning: could not register graph trace events\n");
1553                 return 1;
1554         }
1555
1556         if (!register_trace_event(&graph_trace_ret_event)) {
1557                 pr_warn("Warning: could not register graph trace events\n");
1558                 return 1;
1559         }
1560
1561         return register_tracer(&graph_trace);
1562 }
1563
1564 core_initcall(init_graph_trace);