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