xref: /linux/kernel/trace/trace_output.c (revision b85d45947951d23cb22d90caecf4c1eb81342c96)
1 /*
2  * trace_output.c
3  *
4  * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
5  *
6  */
7 
8 #include <linux/module.h>
9 #include <linux/mutex.h>
10 #include <linux/ftrace.h>
11 
12 #include "trace_output.h"
13 
14 /* must be a power of 2 */
15 #define EVENT_HASHSIZE	128
16 
17 DECLARE_RWSEM(trace_event_sem);
18 
19 static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;
20 
21 static int next_event_type = __TRACE_LAST_TYPE + 1;
22 
23 enum print_line_t trace_print_bputs_msg_only(struct trace_iterator *iter)
24 {
25 	struct trace_seq *s = &iter->seq;
26 	struct trace_entry *entry = iter->ent;
27 	struct bputs_entry *field;
28 
29 	trace_assign_type(field, entry);
30 
31 	trace_seq_puts(s, field->str);
32 
33 	return trace_handle_return(s);
34 }
35 
36 enum print_line_t trace_print_bprintk_msg_only(struct trace_iterator *iter)
37 {
38 	struct trace_seq *s = &iter->seq;
39 	struct trace_entry *entry = iter->ent;
40 	struct bprint_entry *field;
41 
42 	trace_assign_type(field, entry);
43 
44 	trace_seq_bprintf(s, field->fmt, field->buf);
45 
46 	return trace_handle_return(s);
47 }
48 
49 enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter)
50 {
51 	struct trace_seq *s = &iter->seq;
52 	struct trace_entry *entry = iter->ent;
53 	struct print_entry *field;
54 
55 	trace_assign_type(field, entry);
56 
57 	trace_seq_puts(s, field->buf);
58 
59 	return trace_handle_return(s);
60 }
61 
62 const char *
63 trace_print_flags_seq(struct trace_seq *p, const char *delim,
64 		      unsigned long flags,
65 		      const struct trace_print_flags *flag_array)
66 {
67 	unsigned long mask;
68 	const char *str;
69 	const char *ret = trace_seq_buffer_ptr(p);
70 	int i, first = 1;
71 
72 	for (i = 0;  flag_array[i].name && flags; i++) {
73 
74 		mask = flag_array[i].mask;
75 		if ((flags & mask) != mask)
76 			continue;
77 
78 		str = flag_array[i].name;
79 		flags &= ~mask;
80 		if (!first && delim)
81 			trace_seq_puts(p, delim);
82 		else
83 			first = 0;
84 		trace_seq_puts(p, str);
85 	}
86 
87 	/* check for left over flags */
88 	if (flags) {
89 		if (!first && delim)
90 			trace_seq_puts(p, delim);
91 		trace_seq_printf(p, "0x%lx", flags);
92 	}
93 
94 	trace_seq_putc(p, 0);
95 
96 	return ret;
97 }
98 EXPORT_SYMBOL(trace_print_flags_seq);
99 
100 const char *
101 trace_print_symbols_seq(struct trace_seq *p, unsigned long val,
102 			const struct trace_print_flags *symbol_array)
103 {
104 	int i;
105 	const char *ret = trace_seq_buffer_ptr(p);
106 
107 	for (i = 0;  symbol_array[i].name; i++) {
108 
109 		if (val != symbol_array[i].mask)
110 			continue;
111 
112 		trace_seq_puts(p, symbol_array[i].name);
113 		break;
114 	}
115 
116 	if (ret == (const char *)(trace_seq_buffer_ptr(p)))
117 		trace_seq_printf(p, "0x%lx", val);
118 
119 	trace_seq_putc(p, 0);
120 
121 	return ret;
122 }
123 EXPORT_SYMBOL(trace_print_symbols_seq);
124 
125 #if BITS_PER_LONG == 32
126 const char *
127 trace_print_symbols_seq_u64(struct trace_seq *p, unsigned long long val,
128 			 const struct trace_print_flags_u64 *symbol_array)
129 {
130 	int i;
131 	const char *ret = trace_seq_buffer_ptr(p);
132 
133 	for (i = 0;  symbol_array[i].name; i++) {
134 
135 		if (val != symbol_array[i].mask)
136 			continue;
137 
138 		trace_seq_puts(p, symbol_array[i].name);
139 		break;
140 	}
141 
142 	if (ret == (const char *)(trace_seq_buffer_ptr(p)))
143 		trace_seq_printf(p, "0x%llx", val);
144 
145 	trace_seq_putc(p, 0);
146 
147 	return ret;
148 }
149 EXPORT_SYMBOL(trace_print_symbols_seq_u64);
150 #endif
151 
152 const char *
153 trace_print_bitmask_seq(struct trace_seq *p, void *bitmask_ptr,
154 			unsigned int bitmask_size)
155 {
156 	const char *ret = trace_seq_buffer_ptr(p);
157 
158 	trace_seq_bitmask(p, bitmask_ptr, bitmask_size * 8);
159 	trace_seq_putc(p, 0);
160 
161 	return ret;
162 }
163 EXPORT_SYMBOL_GPL(trace_print_bitmask_seq);
164 
165 const char *
166 trace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len)
167 {
168 	int i;
169 	const char *ret = trace_seq_buffer_ptr(p);
170 
171 	for (i = 0; i < buf_len; i++)
172 		trace_seq_printf(p, "%s%2.2x", i == 0 ? "" : " ", buf[i]);
173 
174 	trace_seq_putc(p, 0);
175 
176 	return ret;
177 }
178 EXPORT_SYMBOL(trace_print_hex_seq);
179 
180 const char *
181 trace_print_array_seq(struct trace_seq *p, const void *buf, int count,
182 		      size_t el_size)
183 {
184 	const char *ret = trace_seq_buffer_ptr(p);
185 	const char *prefix = "";
186 	void *ptr = (void *)buf;
187 	size_t buf_len = count * el_size;
188 
189 	trace_seq_putc(p, '{');
190 
191 	while (ptr < buf + buf_len) {
192 		switch (el_size) {
193 		case 1:
194 			trace_seq_printf(p, "%s0x%x", prefix,
195 					 *(u8 *)ptr);
196 			break;
197 		case 2:
198 			trace_seq_printf(p, "%s0x%x", prefix,
199 					 *(u16 *)ptr);
200 			break;
201 		case 4:
202 			trace_seq_printf(p, "%s0x%x", prefix,
203 					 *(u32 *)ptr);
204 			break;
205 		case 8:
206 			trace_seq_printf(p, "%s0x%llx", prefix,
207 					 *(u64 *)ptr);
208 			break;
209 		default:
210 			trace_seq_printf(p, "BAD SIZE:%zu 0x%x", el_size,
211 					 *(u8 *)ptr);
212 			el_size = 1;
213 		}
214 		prefix = ",";
215 		ptr += el_size;
216 	}
217 
218 	trace_seq_putc(p, '}');
219 	trace_seq_putc(p, 0);
220 
221 	return ret;
222 }
223 EXPORT_SYMBOL(trace_print_array_seq);
224 
225 int trace_raw_output_prep(struct trace_iterator *iter,
226 			  struct trace_event *trace_event)
227 {
228 	struct trace_event_call *event;
229 	struct trace_seq *s = &iter->seq;
230 	struct trace_seq *p = &iter->tmp_seq;
231 	struct trace_entry *entry;
232 
233 	event = container_of(trace_event, struct trace_event_call, event);
234 	entry = iter->ent;
235 
236 	if (entry->type != event->event.type) {
237 		WARN_ON_ONCE(1);
238 		return TRACE_TYPE_UNHANDLED;
239 	}
240 
241 	trace_seq_init(p);
242 	trace_seq_printf(s, "%s: ", trace_event_name(event));
243 
244 	return trace_handle_return(s);
245 }
246 EXPORT_SYMBOL(trace_raw_output_prep);
247 
248 static int trace_output_raw(struct trace_iterator *iter, char *name,
249 			    char *fmt, va_list ap)
250 {
251 	struct trace_seq *s = &iter->seq;
252 
253 	trace_seq_printf(s, "%s: ", name);
254 	trace_seq_vprintf(s, fmt, ap);
255 
256 	return trace_handle_return(s);
257 }
258 
259 int trace_output_call(struct trace_iterator *iter, char *name, char *fmt, ...)
260 {
261 	va_list ap;
262 	int ret;
263 
264 	va_start(ap, fmt);
265 	ret = trace_output_raw(iter, name, fmt, ap);
266 	va_end(ap);
267 
268 	return ret;
269 }
270 EXPORT_SYMBOL_GPL(trace_output_call);
271 
272 #ifdef CONFIG_KRETPROBES
273 static inline const char *kretprobed(const char *name)
274 {
275 	static const char tramp_name[] = "kretprobe_trampoline";
276 	int size = sizeof(tramp_name);
277 
278 	if (strncmp(tramp_name, name, size) == 0)
279 		return "[unknown/kretprobe'd]";
280 	return name;
281 }
282 #else
283 static inline const char *kretprobed(const char *name)
284 {
285 	return name;
286 }
287 #endif /* CONFIG_KRETPROBES */
288 
289 static void
290 seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
291 {
292 #ifdef CONFIG_KALLSYMS
293 	char str[KSYM_SYMBOL_LEN];
294 	const char *name;
295 
296 	kallsyms_lookup(address, NULL, NULL, NULL, str);
297 
298 	name = kretprobed(str);
299 
300 	trace_seq_printf(s, fmt, name);
301 #endif
302 }
303 
304 static void
305 seq_print_sym_offset(struct trace_seq *s, const char *fmt,
306 		     unsigned long address)
307 {
308 #ifdef CONFIG_KALLSYMS
309 	char str[KSYM_SYMBOL_LEN];
310 	const char *name;
311 
312 	sprint_symbol(str, address);
313 	name = kretprobed(str);
314 
315 	trace_seq_printf(s, fmt, name);
316 #endif
317 }
318 
319 #ifndef CONFIG_64BIT
320 # define IP_FMT "%08lx"
321 #else
322 # define IP_FMT "%016lx"
323 #endif
324 
325 int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
326 		      unsigned long ip, unsigned long sym_flags)
327 {
328 	struct file *file = NULL;
329 	unsigned long vmstart = 0;
330 	int ret = 1;
331 
332 	if (s->full)
333 		return 0;
334 
335 	if (mm) {
336 		const struct vm_area_struct *vma;
337 
338 		down_read(&mm->mmap_sem);
339 		vma = find_vma(mm, ip);
340 		if (vma) {
341 			file = vma->vm_file;
342 			vmstart = vma->vm_start;
343 		}
344 		if (file) {
345 			ret = trace_seq_path(s, &file->f_path);
346 			if (ret)
347 				trace_seq_printf(s, "[+0x%lx]",
348 						 ip - vmstart);
349 		}
350 		up_read(&mm->mmap_sem);
351 	}
352 	if (ret && ((sym_flags & TRACE_ITER_SYM_ADDR) || !file))
353 		trace_seq_printf(s, " <" IP_FMT ">", ip);
354 	return !trace_seq_has_overflowed(s);
355 }
356 
357 int
358 seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s,
359 		      unsigned long sym_flags)
360 {
361 	struct mm_struct *mm = NULL;
362 	unsigned int i;
363 
364 	if (trace_flags & TRACE_ITER_SYM_USEROBJ) {
365 		struct task_struct *task;
366 		/*
367 		 * we do the lookup on the thread group leader,
368 		 * since individual threads might have already quit!
369 		 */
370 		rcu_read_lock();
371 		task = find_task_by_vpid(entry->tgid);
372 		if (task)
373 			mm = get_task_mm(task);
374 		rcu_read_unlock();
375 	}
376 
377 	for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
378 		unsigned long ip = entry->caller[i];
379 
380 		if (ip == ULONG_MAX || trace_seq_has_overflowed(s))
381 			break;
382 
383 		trace_seq_puts(s, " => ");
384 
385 		if (!ip) {
386 			trace_seq_puts(s, "??");
387 			trace_seq_putc(s, '\n');
388 			continue;
389 		}
390 
391 		seq_print_user_ip(s, mm, ip, sym_flags);
392 		trace_seq_putc(s, '\n');
393 	}
394 
395 	if (mm)
396 		mmput(mm);
397 
398 	return !trace_seq_has_overflowed(s);
399 }
400 
401 int
402 seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
403 {
404 	if (!ip) {
405 		trace_seq_putc(s, '0');
406 		goto out;
407 	}
408 
409 	if (sym_flags & TRACE_ITER_SYM_OFFSET)
410 		seq_print_sym_offset(s, "%s", ip);
411 	else
412 		seq_print_sym_short(s, "%s", ip);
413 
414 	if (sym_flags & TRACE_ITER_SYM_ADDR)
415 		trace_seq_printf(s, " <" IP_FMT ">", ip);
416 
417  out:
418 	return !trace_seq_has_overflowed(s);
419 }
420 
421 /**
422  * trace_print_lat_fmt - print the irq, preempt and lockdep fields
423  * @s: trace seq struct to write to
424  * @entry: The trace entry field from the ring buffer
425  *
426  * Prints the generic fields of irqs off, in hard or softirq, preempt
427  * count.
428  */
429 int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
430 {
431 	char hardsoft_irq;
432 	char need_resched;
433 	char irqs_off;
434 	int hardirq;
435 	int softirq;
436 
437 	hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
438 	softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
439 
440 	irqs_off =
441 		(entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
442 		(entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' :
443 		'.';
444 
445 	switch (entry->flags & (TRACE_FLAG_NEED_RESCHED |
446 				TRACE_FLAG_PREEMPT_RESCHED)) {
447 	case TRACE_FLAG_NEED_RESCHED | TRACE_FLAG_PREEMPT_RESCHED:
448 		need_resched = 'N';
449 		break;
450 	case TRACE_FLAG_NEED_RESCHED:
451 		need_resched = 'n';
452 		break;
453 	case TRACE_FLAG_PREEMPT_RESCHED:
454 		need_resched = 'p';
455 		break;
456 	default:
457 		need_resched = '.';
458 		break;
459 	}
460 
461 	hardsoft_irq =
462 		(hardirq && softirq) ? 'H' :
463 		hardirq ? 'h' :
464 		softirq ? 's' :
465 		'.';
466 
467 	trace_seq_printf(s, "%c%c%c",
468 			 irqs_off, need_resched, hardsoft_irq);
469 
470 	if (entry->preempt_count)
471 		trace_seq_printf(s, "%x", entry->preempt_count);
472 	else
473 		trace_seq_putc(s, '.');
474 
475 	return !trace_seq_has_overflowed(s);
476 }
477 
478 static int
479 lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
480 {
481 	char comm[TASK_COMM_LEN];
482 
483 	trace_find_cmdline(entry->pid, comm);
484 
485 	trace_seq_printf(s, "%8.8s-%-5d %3d",
486 			 comm, entry->pid, cpu);
487 
488 	return trace_print_lat_fmt(s, entry);
489 }
490 
491 #undef MARK
492 #define MARK(v, s) {.val = v, .sym = s}
493 /* trace overhead mark */
494 static const struct trace_mark {
495 	unsigned long long	val; /* unit: nsec */
496 	char			sym;
497 } mark[] = {
498 	MARK(1000000000ULL	, '$'), /* 1 sec */
499 	MARK(100000000ULL	, '@'), /* 100 msec */
500 	MARK(10000000ULL	, '*'), /* 10 msec */
501 	MARK(1000000ULL		, '#'), /* 1000 usecs */
502 	MARK(100000ULL		, '!'), /* 100 usecs */
503 	MARK(10000ULL		, '+'), /* 10 usecs */
504 };
505 #undef MARK
506 
507 char trace_find_mark(unsigned long long d)
508 {
509 	int i;
510 	int size = ARRAY_SIZE(mark);
511 
512 	for (i = 0; i < size; i++) {
513 		if (d > mark[i].val)
514 			break;
515 	}
516 
517 	return (i == size) ? ' ' : mark[i].sym;
518 }
519 
520 static int
521 lat_print_timestamp(struct trace_iterator *iter, u64 next_ts)
522 {
523 	unsigned long verbose = trace_flags & TRACE_ITER_VERBOSE;
524 	unsigned long in_ns = iter->iter_flags & TRACE_FILE_TIME_IN_NS;
525 	unsigned long long abs_ts = iter->ts - iter->trace_buffer->time_start;
526 	unsigned long long rel_ts = next_ts - iter->ts;
527 	struct trace_seq *s = &iter->seq;
528 
529 	if (in_ns) {
530 		abs_ts = ns2usecs(abs_ts);
531 		rel_ts = ns2usecs(rel_ts);
532 	}
533 
534 	if (verbose && in_ns) {
535 		unsigned long abs_usec = do_div(abs_ts, USEC_PER_MSEC);
536 		unsigned long abs_msec = (unsigned long)abs_ts;
537 		unsigned long rel_usec = do_div(rel_ts, USEC_PER_MSEC);
538 		unsigned long rel_msec = (unsigned long)rel_ts;
539 
540 		trace_seq_printf(
541 			s, "[%08llx] %ld.%03ldms (+%ld.%03ldms): ",
542 			ns2usecs(iter->ts),
543 			abs_msec, abs_usec,
544 			rel_msec, rel_usec);
545 
546 	} else if (verbose && !in_ns) {
547 		trace_seq_printf(
548 			s, "[%016llx] %lld (+%lld): ",
549 			iter->ts, abs_ts, rel_ts);
550 
551 	} else if (!verbose && in_ns) {
552 		trace_seq_printf(
553 			s, " %4lldus%c: ",
554 			abs_ts,
555 			trace_find_mark(rel_ts * NSEC_PER_USEC));
556 
557 	} else { /* !verbose && !in_ns */
558 		trace_seq_printf(s, " %4lld: ", abs_ts);
559 	}
560 
561 	return !trace_seq_has_overflowed(s);
562 }
563 
564 int trace_print_context(struct trace_iterator *iter)
565 {
566 	struct trace_seq *s = &iter->seq;
567 	struct trace_entry *entry = iter->ent;
568 	unsigned long long t;
569 	unsigned long secs, usec_rem;
570 	char comm[TASK_COMM_LEN];
571 
572 	trace_find_cmdline(entry->pid, comm);
573 
574 	trace_seq_printf(s, "%16s-%-5d [%03d] ",
575 			       comm, entry->pid, iter->cpu);
576 
577 	if (trace_flags & TRACE_ITER_IRQ_INFO)
578 		trace_print_lat_fmt(s, entry);
579 
580 	if (iter->iter_flags & TRACE_FILE_TIME_IN_NS) {
581 		t = ns2usecs(iter->ts);
582 		usec_rem = do_div(t, USEC_PER_SEC);
583 		secs = (unsigned long)t;
584 		trace_seq_printf(s, " %5lu.%06lu: ", secs, usec_rem);
585 	} else
586 		trace_seq_printf(s, " %12llu: ", iter->ts);
587 
588 	return !trace_seq_has_overflowed(s);
589 }
590 
591 int trace_print_lat_context(struct trace_iterator *iter)
592 {
593 	u64 next_ts;
594 	/* trace_find_next_entry will reset ent_size */
595 	int ent_size = iter->ent_size;
596 	struct trace_seq *s = &iter->seq;
597 	struct trace_entry *entry = iter->ent,
598 			   *next_entry = trace_find_next_entry(iter, NULL,
599 							       &next_ts);
600 	unsigned long verbose = (trace_flags & TRACE_ITER_VERBOSE);
601 
602 	/* Restore the original ent_size */
603 	iter->ent_size = ent_size;
604 
605 	if (!next_entry)
606 		next_ts = iter->ts;
607 
608 	if (verbose) {
609 		char comm[TASK_COMM_LEN];
610 
611 		trace_find_cmdline(entry->pid, comm);
612 
613 		trace_seq_printf(
614 			s, "%16s %5d %3d %d %08x %08lx ",
615 			comm, entry->pid, iter->cpu, entry->flags,
616 			entry->preempt_count, iter->idx);
617 	} else {
618 		lat_print_generic(s, entry, iter->cpu);
619 	}
620 
621 	lat_print_timestamp(iter, next_ts);
622 
623 	return !trace_seq_has_overflowed(s);
624 }
625 
626 static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
627 
628 static int task_state_char(unsigned long state)
629 {
630 	int bit = state ? __ffs(state) + 1 : 0;
631 
632 	return bit < sizeof(state_to_char) - 1 ? state_to_char[bit] : '?';
633 }
634 
635 /**
636  * ftrace_find_event - find a registered event
637  * @type: the type of event to look for
638  *
639  * Returns an event of type @type otherwise NULL
640  * Called with trace_event_read_lock() held.
641  */
642 struct trace_event *ftrace_find_event(int type)
643 {
644 	struct trace_event *event;
645 	unsigned key;
646 
647 	key = type & (EVENT_HASHSIZE - 1);
648 
649 	hlist_for_each_entry(event, &event_hash[key], node) {
650 		if (event->type == type)
651 			return event;
652 	}
653 
654 	return NULL;
655 }
656 
657 static LIST_HEAD(ftrace_event_list);
658 
659 static int trace_search_list(struct list_head **list)
660 {
661 	struct trace_event *e;
662 	int last = __TRACE_LAST_TYPE;
663 
664 	if (list_empty(&ftrace_event_list)) {
665 		*list = &ftrace_event_list;
666 		return last + 1;
667 	}
668 
669 	/*
670 	 * We used up all possible max events,
671 	 * lets see if somebody freed one.
672 	 */
673 	list_for_each_entry(e, &ftrace_event_list, list) {
674 		if (e->type != last + 1)
675 			break;
676 		last++;
677 	}
678 
679 	/* Did we used up all 65 thousand events??? */
680 	if ((last + 1) > TRACE_EVENT_TYPE_MAX)
681 		return 0;
682 
683 	*list = &e->list;
684 	return last + 1;
685 }
686 
687 void trace_event_read_lock(void)
688 {
689 	down_read(&trace_event_sem);
690 }
691 
692 void trace_event_read_unlock(void)
693 {
694 	up_read(&trace_event_sem);
695 }
696 
697 /**
698  * register_trace_event - register output for an event type
699  * @event: the event type to register
700  *
701  * Event types are stored in a hash and this hash is used to
702  * find a way to print an event. If the @event->type is set
703  * then it will use that type, otherwise it will assign a
704  * type to use.
705  *
706  * If you assign your own type, please make sure it is added
707  * to the trace_type enum in trace.h, to avoid collisions
708  * with the dynamic types.
709  *
710  * Returns the event type number or zero on error.
711  */
712 int register_trace_event(struct trace_event *event)
713 {
714 	unsigned key;
715 	int ret = 0;
716 
717 	down_write(&trace_event_sem);
718 
719 	if (WARN_ON(!event))
720 		goto out;
721 
722 	if (WARN_ON(!event->funcs))
723 		goto out;
724 
725 	INIT_LIST_HEAD(&event->list);
726 
727 	if (!event->type) {
728 		struct list_head *list = NULL;
729 
730 		if (next_event_type > TRACE_EVENT_TYPE_MAX) {
731 
732 			event->type = trace_search_list(&list);
733 			if (!event->type)
734 				goto out;
735 
736 		} else {
737 
738 			event->type = next_event_type++;
739 			list = &ftrace_event_list;
740 		}
741 
742 		if (WARN_ON(ftrace_find_event(event->type)))
743 			goto out;
744 
745 		list_add_tail(&event->list, list);
746 
747 	} else if (event->type > __TRACE_LAST_TYPE) {
748 		printk(KERN_WARNING "Need to add type to trace.h\n");
749 		WARN_ON(1);
750 		goto out;
751 	} else {
752 		/* Is this event already used */
753 		if (ftrace_find_event(event->type))
754 			goto out;
755 	}
756 
757 	if (event->funcs->trace == NULL)
758 		event->funcs->trace = trace_nop_print;
759 	if (event->funcs->raw == NULL)
760 		event->funcs->raw = trace_nop_print;
761 	if (event->funcs->hex == NULL)
762 		event->funcs->hex = trace_nop_print;
763 	if (event->funcs->binary == NULL)
764 		event->funcs->binary = trace_nop_print;
765 
766 	key = event->type & (EVENT_HASHSIZE - 1);
767 
768 	hlist_add_head(&event->node, &event_hash[key]);
769 
770 	ret = event->type;
771  out:
772 	up_write(&trace_event_sem);
773 
774 	return ret;
775 }
776 EXPORT_SYMBOL_GPL(register_trace_event);
777 
778 /*
779  * Used by module code with the trace_event_sem held for write.
780  */
781 int __unregister_trace_event(struct trace_event *event)
782 {
783 	hlist_del(&event->node);
784 	list_del(&event->list);
785 	return 0;
786 }
787 
788 /**
789  * unregister_trace_event - remove a no longer used event
790  * @event: the event to remove
791  */
792 int unregister_trace_event(struct trace_event *event)
793 {
794 	down_write(&trace_event_sem);
795 	__unregister_trace_event(event);
796 	up_write(&trace_event_sem);
797 
798 	return 0;
799 }
800 EXPORT_SYMBOL_GPL(unregister_trace_event);
801 
802 /*
803  * Standard events
804  */
805 
806 enum print_line_t trace_nop_print(struct trace_iterator *iter, int flags,
807 				  struct trace_event *event)
808 {
809 	trace_seq_printf(&iter->seq, "type: %d\n", iter->ent->type);
810 
811 	return trace_handle_return(&iter->seq);
812 }
813 
814 /* TRACE_FN */
815 static enum print_line_t trace_fn_trace(struct trace_iterator *iter, int flags,
816 					struct trace_event *event)
817 {
818 	struct ftrace_entry *field;
819 	struct trace_seq *s = &iter->seq;
820 
821 	trace_assign_type(field, iter->ent);
822 
823 	seq_print_ip_sym(s, field->ip, flags);
824 
825 	if ((flags & TRACE_ITER_PRINT_PARENT) && field->parent_ip) {
826 		trace_seq_puts(s, " <-");
827 		seq_print_ip_sym(s, field->parent_ip, flags);
828 	}
829 
830 	trace_seq_putc(s, '\n');
831 
832 	return trace_handle_return(s);
833 }
834 
835 static enum print_line_t trace_fn_raw(struct trace_iterator *iter, int flags,
836 				      struct trace_event *event)
837 {
838 	struct ftrace_entry *field;
839 
840 	trace_assign_type(field, iter->ent);
841 
842 	trace_seq_printf(&iter->seq, "%lx %lx\n",
843 			 field->ip,
844 			 field->parent_ip);
845 
846 	return trace_handle_return(&iter->seq);
847 }
848 
849 static enum print_line_t trace_fn_hex(struct trace_iterator *iter, int flags,
850 				      struct trace_event *event)
851 {
852 	struct ftrace_entry *field;
853 	struct trace_seq *s = &iter->seq;
854 
855 	trace_assign_type(field, iter->ent);
856 
857 	SEQ_PUT_HEX_FIELD(s, field->ip);
858 	SEQ_PUT_HEX_FIELD(s, field->parent_ip);
859 
860 	return trace_handle_return(s);
861 }
862 
863 static enum print_line_t trace_fn_bin(struct trace_iterator *iter, int flags,
864 				      struct trace_event *event)
865 {
866 	struct ftrace_entry *field;
867 	struct trace_seq *s = &iter->seq;
868 
869 	trace_assign_type(field, iter->ent);
870 
871 	SEQ_PUT_FIELD(s, field->ip);
872 	SEQ_PUT_FIELD(s, field->parent_ip);
873 
874 	return trace_handle_return(s);
875 }
876 
877 static struct trace_event_functions trace_fn_funcs = {
878 	.trace		= trace_fn_trace,
879 	.raw		= trace_fn_raw,
880 	.hex		= trace_fn_hex,
881 	.binary		= trace_fn_bin,
882 };
883 
884 static struct trace_event trace_fn_event = {
885 	.type		= TRACE_FN,
886 	.funcs		= &trace_fn_funcs,
887 };
888 
889 /* TRACE_CTX an TRACE_WAKE */
890 static enum print_line_t trace_ctxwake_print(struct trace_iterator *iter,
891 					     char *delim)
892 {
893 	struct ctx_switch_entry *field;
894 	char comm[TASK_COMM_LEN];
895 	int S, T;
896 
897 
898 	trace_assign_type(field, iter->ent);
899 
900 	T = task_state_char(field->next_state);
901 	S = task_state_char(field->prev_state);
902 	trace_find_cmdline(field->next_pid, comm);
903 	trace_seq_printf(&iter->seq,
904 			 " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
905 			 field->prev_pid,
906 			 field->prev_prio,
907 			 S, delim,
908 			 field->next_cpu,
909 			 field->next_pid,
910 			 field->next_prio,
911 			 T, comm);
912 
913 	return trace_handle_return(&iter->seq);
914 }
915 
916 static enum print_line_t trace_ctx_print(struct trace_iterator *iter, int flags,
917 					 struct trace_event *event)
918 {
919 	return trace_ctxwake_print(iter, "==>");
920 }
921 
922 static enum print_line_t trace_wake_print(struct trace_iterator *iter,
923 					  int flags, struct trace_event *event)
924 {
925 	return trace_ctxwake_print(iter, "  +");
926 }
927 
928 static int trace_ctxwake_raw(struct trace_iterator *iter, char S)
929 {
930 	struct ctx_switch_entry *field;
931 	int T;
932 
933 	trace_assign_type(field, iter->ent);
934 
935 	if (!S)
936 		S = task_state_char(field->prev_state);
937 	T = task_state_char(field->next_state);
938 	trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
939 			 field->prev_pid,
940 			 field->prev_prio,
941 			 S,
942 			 field->next_cpu,
943 			 field->next_pid,
944 			 field->next_prio,
945 			 T);
946 
947 	return trace_handle_return(&iter->seq);
948 }
949 
950 static enum print_line_t trace_ctx_raw(struct trace_iterator *iter, int flags,
951 				       struct trace_event *event)
952 {
953 	return trace_ctxwake_raw(iter, 0);
954 }
955 
956 static enum print_line_t trace_wake_raw(struct trace_iterator *iter, int flags,
957 					struct trace_event *event)
958 {
959 	return trace_ctxwake_raw(iter, '+');
960 }
961 
962 
963 static int trace_ctxwake_hex(struct trace_iterator *iter, char S)
964 {
965 	struct ctx_switch_entry *field;
966 	struct trace_seq *s = &iter->seq;
967 	int T;
968 
969 	trace_assign_type(field, iter->ent);
970 
971 	if (!S)
972 		S = task_state_char(field->prev_state);
973 	T = task_state_char(field->next_state);
974 
975 	SEQ_PUT_HEX_FIELD(s, field->prev_pid);
976 	SEQ_PUT_HEX_FIELD(s, field->prev_prio);
977 	SEQ_PUT_HEX_FIELD(s, S);
978 	SEQ_PUT_HEX_FIELD(s, field->next_cpu);
979 	SEQ_PUT_HEX_FIELD(s, field->next_pid);
980 	SEQ_PUT_HEX_FIELD(s, field->next_prio);
981 	SEQ_PUT_HEX_FIELD(s, T);
982 
983 	return trace_handle_return(s);
984 }
985 
986 static enum print_line_t trace_ctx_hex(struct trace_iterator *iter, int flags,
987 				       struct trace_event *event)
988 {
989 	return trace_ctxwake_hex(iter, 0);
990 }
991 
992 static enum print_line_t trace_wake_hex(struct trace_iterator *iter, int flags,
993 					struct trace_event *event)
994 {
995 	return trace_ctxwake_hex(iter, '+');
996 }
997 
998 static enum print_line_t trace_ctxwake_bin(struct trace_iterator *iter,
999 					   int flags, struct trace_event *event)
1000 {
1001 	struct ctx_switch_entry *field;
1002 	struct trace_seq *s = &iter->seq;
1003 
1004 	trace_assign_type(field, iter->ent);
1005 
1006 	SEQ_PUT_FIELD(s, field->prev_pid);
1007 	SEQ_PUT_FIELD(s, field->prev_prio);
1008 	SEQ_PUT_FIELD(s, field->prev_state);
1009 	SEQ_PUT_FIELD(s, field->next_cpu);
1010 	SEQ_PUT_FIELD(s, field->next_pid);
1011 	SEQ_PUT_FIELD(s, field->next_prio);
1012 	SEQ_PUT_FIELD(s, field->next_state);
1013 
1014 	return trace_handle_return(s);
1015 }
1016 
1017 static struct trace_event_functions trace_ctx_funcs = {
1018 	.trace		= trace_ctx_print,
1019 	.raw		= trace_ctx_raw,
1020 	.hex		= trace_ctx_hex,
1021 	.binary		= trace_ctxwake_bin,
1022 };
1023 
1024 static struct trace_event trace_ctx_event = {
1025 	.type		= TRACE_CTX,
1026 	.funcs		= &trace_ctx_funcs,
1027 };
1028 
1029 static struct trace_event_functions trace_wake_funcs = {
1030 	.trace		= trace_wake_print,
1031 	.raw		= trace_wake_raw,
1032 	.hex		= trace_wake_hex,
1033 	.binary		= trace_ctxwake_bin,
1034 };
1035 
1036 static struct trace_event trace_wake_event = {
1037 	.type		= TRACE_WAKE,
1038 	.funcs		= &trace_wake_funcs,
1039 };
1040 
1041 /* TRACE_STACK */
1042 
1043 static enum print_line_t trace_stack_print(struct trace_iterator *iter,
1044 					   int flags, struct trace_event *event)
1045 {
1046 	struct stack_entry *field;
1047 	struct trace_seq *s = &iter->seq;
1048 	unsigned long *p;
1049 	unsigned long *end;
1050 
1051 	trace_assign_type(field, iter->ent);
1052 	end = (unsigned long *)((long)iter->ent + iter->ent_size);
1053 
1054 	trace_seq_puts(s, "<stack trace>\n");
1055 
1056 	for (p = field->caller; p && *p != ULONG_MAX && p < end; p++) {
1057 
1058 		if (trace_seq_has_overflowed(s))
1059 			break;
1060 
1061 		trace_seq_puts(s, " => ");
1062 		seq_print_ip_sym(s, *p, flags);
1063 		trace_seq_putc(s, '\n');
1064 	}
1065 
1066 	return trace_handle_return(s);
1067 }
1068 
1069 static struct trace_event_functions trace_stack_funcs = {
1070 	.trace		= trace_stack_print,
1071 };
1072 
1073 static struct trace_event trace_stack_event = {
1074 	.type		= TRACE_STACK,
1075 	.funcs		= &trace_stack_funcs,
1076 };
1077 
1078 /* TRACE_USER_STACK */
1079 static enum print_line_t trace_user_stack_print(struct trace_iterator *iter,
1080 						int flags, struct trace_event *event)
1081 {
1082 	struct userstack_entry *field;
1083 	struct trace_seq *s = &iter->seq;
1084 
1085 	trace_assign_type(field, iter->ent);
1086 
1087 	trace_seq_puts(s, "<user stack trace>\n");
1088 	seq_print_userip_objs(field, s, flags);
1089 
1090 	return trace_handle_return(s);
1091 }
1092 
1093 static struct trace_event_functions trace_user_stack_funcs = {
1094 	.trace		= trace_user_stack_print,
1095 };
1096 
1097 static struct trace_event trace_user_stack_event = {
1098 	.type		= TRACE_USER_STACK,
1099 	.funcs		= &trace_user_stack_funcs,
1100 };
1101 
1102 /* TRACE_BPUTS */
1103 static enum print_line_t
1104 trace_bputs_print(struct trace_iterator *iter, int flags,
1105 		   struct trace_event *event)
1106 {
1107 	struct trace_entry *entry = iter->ent;
1108 	struct trace_seq *s = &iter->seq;
1109 	struct bputs_entry *field;
1110 
1111 	trace_assign_type(field, entry);
1112 
1113 	seq_print_ip_sym(s, field->ip, flags);
1114 	trace_seq_puts(s, ": ");
1115 	trace_seq_puts(s, field->str);
1116 
1117 	return trace_handle_return(s);
1118 }
1119 
1120 
1121 static enum print_line_t
1122 trace_bputs_raw(struct trace_iterator *iter, int flags,
1123 		struct trace_event *event)
1124 {
1125 	struct bputs_entry *field;
1126 	struct trace_seq *s = &iter->seq;
1127 
1128 	trace_assign_type(field, iter->ent);
1129 
1130 	trace_seq_printf(s, ": %lx : ", field->ip);
1131 	trace_seq_puts(s, field->str);
1132 
1133 	return trace_handle_return(s);
1134 }
1135 
1136 static struct trace_event_functions trace_bputs_funcs = {
1137 	.trace		= trace_bputs_print,
1138 	.raw		= trace_bputs_raw,
1139 };
1140 
1141 static struct trace_event trace_bputs_event = {
1142 	.type		= TRACE_BPUTS,
1143 	.funcs		= &trace_bputs_funcs,
1144 };
1145 
1146 /* TRACE_BPRINT */
1147 static enum print_line_t
1148 trace_bprint_print(struct trace_iterator *iter, int flags,
1149 		   struct trace_event *event)
1150 {
1151 	struct trace_entry *entry = iter->ent;
1152 	struct trace_seq *s = &iter->seq;
1153 	struct bprint_entry *field;
1154 
1155 	trace_assign_type(field, entry);
1156 
1157 	seq_print_ip_sym(s, field->ip, flags);
1158 	trace_seq_puts(s, ": ");
1159 	trace_seq_bprintf(s, field->fmt, field->buf);
1160 
1161 	return trace_handle_return(s);
1162 }
1163 
1164 
1165 static enum print_line_t
1166 trace_bprint_raw(struct trace_iterator *iter, int flags,
1167 		 struct trace_event *event)
1168 {
1169 	struct bprint_entry *field;
1170 	struct trace_seq *s = &iter->seq;
1171 
1172 	trace_assign_type(field, iter->ent);
1173 
1174 	trace_seq_printf(s, ": %lx : ", field->ip);
1175 	trace_seq_bprintf(s, field->fmt, field->buf);
1176 
1177 	return trace_handle_return(s);
1178 }
1179 
1180 static struct trace_event_functions trace_bprint_funcs = {
1181 	.trace		= trace_bprint_print,
1182 	.raw		= trace_bprint_raw,
1183 };
1184 
1185 static struct trace_event trace_bprint_event = {
1186 	.type		= TRACE_BPRINT,
1187 	.funcs		= &trace_bprint_funcs,
1188 };
1189 
1190 /* TRACE_PRINT */
1191 static enum print_line_t trace_print_print(struct trace_iterator *iter,
1192 					   int flags, struct trace_event *event)
1193 {
1194 	struct print_entry *field;
1195 	struct trace_seq *s = &iter->seq;
1196 
1197 	trace_assign_type(field, iter->ent);
1198 
1199 	seq_print_ip_sym(s, field->ip, flags);
1200 	trace_seq_printf(s, ": %s", field->buf);
1201 
1202 	return trace_handle_return(s);
1203 }
1204 
1205 static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags,
1206 					 struct trace_event *event)
1207 {
1208 	struct print_entry *field;
1209 
1210 	trace_assign_type(field, iter->ent);
1211 
1212 	trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf);
1213 
1214 	return trace_handle_return(&iter->seq);
1215 }
1216 
1217 static struct trace_event_functions trace_print_funcs = {
1218 	.trace		= trace_print_print,
1219 	.raw		= trace_print_raw,
1220 };
1221 
1222 static struct trace_event trace_print_event = {
1223 	.type	 	= TRACE_PRINT,
1224 	.funcs		= &trace_print_funcs,
1225 };
1226 
1227 
1228 static struct trace_event *events[] __initdata = {
1229 	&trace_fn_event,
1230 	&trace_ctx_event,
1231 	&trace_wake_event,
1232 	&trace_stack_event,
1233 	&trace_user_stack_event,
1234 	&trace_bputs_event,
1235 	&trace_bprint_event,
1236 	&trace_print_event,
1237 	NULL
1238 };
1239 
1240 __init static int init_events(void)
1241 {
1242 	struct trace_event *event;
1243 	int i, ret;
1244 
1245 	for (i = 0; events[i]; i++) {
1246 		event = events[i];
1247 
1248 		ret = register_trace_event(event);
1249 		if (!ret) {
1250 			printk(KERN_WARNING "event %d failed to register\n",
1251 			       event->type);
1252 			WARN_ON_ONCE(1);
1253 		}
1254 	}
1255 
1256 	return 0;
1257 }
1258 early_initcall(init_events);
1259