xref: /openbmc/linux/kernel/trace/trace_output.c (revision e2f1cf25)
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(1000000ULL		, '#'), /* 1000 usecs */
500 	MARK(100000ULL		, '!'), /* 100 usecs */
501 	MARK(10000ULL		, '+'), /* 10 usecs */
502 };
503 #undef MARK
504 
505 char trace_find_mark(unsigned long long d)
506 {
507 	int i;
508 	int size = ARRAY_SIZE(mark);
509 
510 	for (i = 0; i < size; i++) {
511 		if (d >= mark[i].val)
512 			break;
513 	}
514 
515 	return (i == size) ? ' ' : mark[i].sym;
516 }
517 
518 static int
519 lat_print_timestamp(struct trace_iterator *iter, u64 next_ts)
520 {
521 	unsigned long verbose = trace_flags & TRACE_ITER_VERBOSE;
522 	unsigned long in_ns = iter->iter_flags & TRACE_FILE_TIME_IN_NS;
523 	unsigned long long abs_ts = iter->ts - iter->trace_buffer->time_start;
524 	unsigned long long rel_ts = next_ts - iter->ts;
525 	struct trace_seq *s = &iter->seq;
526 
527 	if (in_ns) {
528 		abs_ts = ns2usecs(abs_ts);
529 		rel_ts = ns2usecs(rel_ts);
530 	}
531 
532 	if (verbose && in_ns) {
533 		unsigned long abs_usec = do_div(abs_ts, USEC_PER_MSEC);
534 		unsigned long abs_msec = (unsigned long)abs_ts;
535 		unsigned long rel_usec = do_div(rel_ts, USEC_PER_MSEC);
536 		unsigned long rel_msec = (unsigned long)rel_ts;
537 
538 		trace_seq_printf(
539 			s, "[%08llx] %ld.%03ldms (+%ld.%03ldms): ",
540 			ns2usecs(iter->ts),
541 			abs_msec, abs_usec,
542 			rel_msec, rel_usec);
543 
544 	} else if (verbose && !in_ns) {
545 		trace_seq_printf(
546 			s, "[%016llx] %lld (+%lld): ",
547 			iter->ts, abs_ts, rel_ts);
548 
549 	} else if (!verbose && in_ns) {
550 		trace_seq_printf(
551 			s, " %4lldus%c: ",
552 			abs_ts,
553 			trace_find_mark(rel_ts * NSEC_PER_USEC));
554 
555 	} else { /* !verbose && !in_ns */
556 		trace_seq_printf(s, " %4lld: ", abs_ts);
557 	}
558 
559 	return !trace_seq_has_overflowed(s);
560 }
561 
562 int trace_print_context(struct trace_iterator *iter)
563 {
564 	struct trace_seq *s = &iter->seq;
565 	struct trace_entry *entry = iter->ent;
566 	unsigned long long t;
567 	unsigned long secs, usec_rem;
568 	char comm[TASK_COMM_LEN];
569 
570 	trace_find_cmdline(entry->pid, comm);
571 
572 	trace_seq_printf(s, "%16s-%-5d [%03d] ",
573 			       comm, entry->pid, iter->cpu);
574 
575 	if (trace_flags & TRACE_ITER_IRQ_INFO)
576 		trace_print_lat_fmt(s, entry);
577 
578 	if (iter->iter_flags & TRACE_FILE_TIME_IN_NS) {
579 		t = ns2usecs(iter->ts);
580 		usec_rem = do_div(t, USEC_PER_SEC);
581 		secs = (unsigned long)t;
582 		trace_seq_printf(s, " %5lu.%06lu: ", secs, usec_rem);
583 	} else
584 		trace_seq_printf(s, " %12llu: ", iter->ts);
585 
586 	return !trace_seq_has_overflowed(s);
587 }
588 
589 int trace_print_lat_context(struct trace_iterator *iter)
590 {
591 	u64 next_ts;
592 	/* trace_find_next_entry will reset ent_size */
593 	int ent_size = iter->ent_size;
594 	struct trace_seq *s = &iter->seq;
595 	struct trace_entry *entry = iter->ent,
596 			   *next_entry = trace_find_next_entry(iter, NULL,
597 							       &next_ts);
598 	unsigned long verbose = (trace_flags & TRACE_ITER_VERBOSE);
599 
600 	/* Restore the original ent_size */
601 	iter->ent_size = ent_size;
602 
603 	if (!next_entry)
604 		next_ts = iter->ts;
605 
606 	if (verbose) {
607 		char comm[TASK_COMM_LEN];
608 
609 		trace_find_cmdline(entry->pid, comm);
610 
611 		trace_seq_printf(
612 			s, "%16s %5d %3d %d %08x %08lx ",
613 			comm, entry->pid, iter->cpu, entry->flags,
614 			entry->preempt_count, iter->idx);
615 	} else {
616 		lat_print_generic(s, entry, iter->cpu);
617 	}
618 
619 	lat_print_timestamp(iter, next_ts);
620 
621 	return !trace_seq_has_overflowed(s);
622 }
623 
624 static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
625 
626 static int task_state_char(unsigned long state)
627 {
628 	int bit = state ? __ffs(state) + 1 : 0;
629 
630 	return bit < sizeof(state_to_char) - 1 ? state_to_char[bit] : '?';
631 }
632 
633 /**
634  * ftrace_find_event - find a registered event
635  * @type: the type of event to look for
636  *
637  * Returns an event of type @type otherwise NULL
638  * Called with trace_event_read_lock() held.
639  */
640 struct trace_event *ftrace_find_event(int type)
641 {
642 	struct trace_event *event;
643 	unsigned key;
644 
645 	key = type & (EVENT_HASHSIZE - 1);
646 
647 	hlist_for_each_entry(event, &event_hash[key], node) {
648 		if (event->type == type)
649 			return event;
650 	}
651 
652 	return NULL;
653 }
654 
655 static LIST_HEAD(ftrace_event_list);
656 
657 static int trace_search_list(struct list_head **list)
658 {
659 	struct trace_event *e;
660 	int last = __TRACE_LAST_TYPE;
661 
662 	if (list_empty(&ftrace_event_list)) {
663 		*list = &ftrace_event_list;
664 		return last + 1;
665 	}
666 
667 	/*
668 	 * We used up all possible max events,
669 	 * lets see if somebody freed one.
670 	 */
671 	list_for_each_entry(e, &ftrace_event_list, list) {
672 		if (e->type != last + 1)
673 			break;
674 		last++;
675 	}
676 
677 	/* Did we used up all 65 thousand events??? */
678 	if ((last + 1) > TRACE_EVENT_TYPE_MAX)
679 		return 0;
680 
681 	*list = &e->list;
682 	return last + 1;
683 }
684 
685 void trace_event_read_lock(void)
686 {
687 	down_read(&trace_event_sem);
688 }
689 
690 void trace_event_read_unlock(void)
691 {
692 	up_read(&trace_event_sem);
693 }
694 
695 /**
696  * register_trace_event - register output for an event type
697  * @event: the event type to register
698  *
699  * Event types are stored in a hash and this hash is used to
700  * find a way to print an event. If the @event->type is set
701  * then it will use that type, otherwise it will assign a
702  * type to use.
703  *
704  * If you assign your own type, please make sure it is added
705  * to the trace_type enum in trace.h, to avoid collisions
706  * with the dynamic types.
707  *
708  * Returns the event type number or zero on error.
709  */
710 int register_trace_event(struct trace_event *event)
711 {
712 	unsigned key;
713 	int ret = 0;
714 
715 	down_write(&trace_event_sem);
716 
717 	if (WARN_ON(!event))
718 		goto out;
719 
720 	if (WARN_ON(!event->funcs))
721 		goto out;
722 
723 	INIT_LIST_HEAD(&event->list);
724 
725 	if (!event->type) {
726 		struct list_head *list = NULL;
727 
728 		if (next_event_type > TRACE_EVENT_TYPE_MAX) {
729 
730 			event->type = trace_search_list(&list);
731 			if (!event->type)
732 				goto out;
733 
734 		} else {
735 
736 			event->type = next_event_type++;
737 			list = &ftrace_event_list;
738 		}
739 
740 		if (WARN_ON(ftrace_find_event(event->type)))
741 			goto out;
742 
743 		list_add_tail(&event->list, list);
744 
745 	} else if (event->type > __TRACE_LAST_TYPE) {
746 		printk(KERN_WARNING "Need to add type to trace.h\n");
747 		WARN_ON(1);
748 		goto out;
749 	} else {
750 		/* Is this event already used */
751 		if (ftrace_find_event(event->type))
752 			goto out;
753 	}
754 
755 	if (event->funcs->trace == NULL)
756 		event->funcs->trace = trace_nop_print;
757 	if (event->funcs->raw == NULL)
758 		event->funcs->raw = trace_nop_print;
759 	if (event->funcs->hex == NULL)
760 		event->funcs->hex = trace_nop_print;
761 	if (event->funcs->binary == NULL)
762 		event->funcs->binary = trace_nop_print;
763 
764 	key = event->type & (EVENT_HASHSIZE - 1);
765 
766 	hlist_add_head(&event->node, &event_hash[key]);
767 
768 	ret = event->type;
769  out:
770 	up_write(&trace_event_sem);
771 
772 	return ret;
773 }
774 EXPORT_SYMBOL_GPL(register_trace_event);
775 
776 /*
777  * Used by module code with the trace_event_sem held for write.
778  */
779 int __unregister_trace_event(struct trace_event *event)
780 {
781 	hlist_del(&event->node);
782 	list_del(&event->list);
783 	return 0;
784 }
785 
786 /**
787  * unregister_trace_event - remove a no longer used event
788  * @event: the event to remove
789  */
790 int unregister_trace_event(struct trace_event *event)
791 {
792 	down_write(&trace_event_sem);
793 	__unregister_trace_event(event);
794 	up_write(&trace_event_sem);
795 
796 	return 0;
797 }
798 EXPORT_SYMBOL_GPL(unregister_trace_event);
799 
800 /*
801  * Standard events
802  */
803 
804 enum print_line_t trace_nop_print(struct trace_iterator *iter, int flags,
805 				  struct trace_event *event)
806 {
807 	trace_seq_printf(&iter->seq, "type: %d\n", iter->ent->type);
808 
809 	return trace_handle_return(&iter->seq);
810 }
811 
812 /* TRACE_FN */
813 static enum print_line_t trace_fn_trace(struct trace_iterator *iter, int flags,
814 					struct trace_event *event)
815 {
816 	struct ftrace_entry *field;
817 	struct trace_seq *s = &iter->seq;
818 
819 	trace_assign_type(field, iter->ent);
820 
821 	seq_print_ip_sym(s, field->ip, flags);
822 
823 	if ((flags & TRACE_ITER_PRINT_PARENT) && field->parent_ip) {
824 		trace_seq_puts(s, " <-");
825 		seq_print_ip_sym(s, field->parent_ip, flags);
826 	}
827 
828 	trace_seq_putc(s, '\n');
829 
830 	return trace_handle_return(s);
831 }
832 
833 static enum print_line_t trace_fn_raw(struct trace_iterator *iter, int flags,
834 				      struct trace_event *event)
835 {
836 	struct ftrace_entry *field;
837 
838 	trace_assign_type(field, iter->ent);
839 
840 	trace_seq_printf(&iter->seq, "%lx %lx\n",
841 			 field->ip,
842 			 field->parent_ip);
843 
844 	return trace_handle_return(&iter->seq);
845 }
846 
847 static enum print_line_t trace_fn_hex(struct trace_iterator *iter, int flags,
848 				      struct trace_event *event)
849 {
850 	struct ftrace_entry *field;
851 	struct trace_seq *s = &iter->seq;
852 
853 	trace_assign_type(field, iter->ent);
854 
855 	SEQ_PUT_HEX_FIELD(s, field->ip);
856 	SEQ_PUT_HEX_FIELD(s, field->parent_ip);
857 
858 	return trace_handle_return(s);
859 }
860 
861 static enum print_line_t trace_fn_bin(struct trace_iterator *iter, int flags,
862 				      struct trace_event *event)
863 {
864 	struct ftrace_entry *field;
865 	struct trace_seq *s = &iter->seq;
866 
867 	trace_assign_type(field, iter->ent);
868 
869 	SEQ_PUT_FIELD(s, field->ip);
870 	SEQ_PUT_FIELD(s, field->parent_ip);
871 
872 	return trace_handle_return(s);
873 }
874 
875 static struct trace_event_functions trace_fn_funcs = {
876 	.trace		= trace_fn_trace,
877 	.raw		= trace_fn_raw,
878 	.hex		= trace_fn_hex,
879 	.binary		= trace_fn_bin,
880 };
881 
882 static struct trace_event trace_fn_event = {
883 	.type		= TRACE_FN,
884 	.funcs		= &trace_fn_funcs,
885 };
886 
887 /* TRACE_CTX an TRACE_WAKE */
888 static enum print_line_t trace_ctxwake_print(struct trace_iterator *iter,
889 					     char *delim)
890 {
891 	struct ctx_switch_entry *field;
892 	char comm[TASK_COMM_LEN];
893 	int S, T;
894 
895 
896 	trace_assign_type(field, iter->ent);
897 
898 	T = task_state_char(field->next_state);
899 	S = task_state_char(field->prev_state);
900 	trace_find_cmdline(field->next_pid, comm);
901 	trace_seq_printf(&iter->seq,
902 			 " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
903 			 field->prev_pid,
904 			 field->prev_prio,
905 			 S, delim,
906 			 field->next_cpu,
907 			 field->next_pid,
908 			 field->next_prio,
909 			 T, comm);
910 
911 	return trace_handle_return(&iter->seq);
912 }
913 
914 static enum print_line_t trace_ctx_print(struct trace_iterator *iter, int flags,
915 					 struct trace_event *event)
916 {
917 	return trace_ctxwake_print(iter, "==>");
918 }
919 
920 static enum print_line_t trace_wake_print(struct trace_iterator *iter,
921 					  int flags, struct trace_event *event)
922 {
923 	return trace_ctxwake_print(iter, "  +");
924 }
925 
926 static int trace_ctxwake_raw(struct trace_iterator *iter, char S)
927 {
928 	struct ctx_switch_entry *field;
929 	int T;
930 
931 	trace_assign_type(field, iter->ent);
932 
933 	if (!S)
934 		S = task_state_char(field->prev_state);
935 	T = task_state_char(field->next_state);
936 	trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
937 			 field->prev_pid,
938 			 field->prev_prio,
939 			 S,
940 			 field->next_cpu,
941 			 field->next_pid,
942 			 field->next_prio,
943 			 T);
944 
945 	return trace_handle_return(&iter->seq);
946 }
947 
948 static enum print_line_t trace_ctx_raw(struct trace_iterator *iter, int flags,
949 				       struct trace_event *event)
950 {
951 	return trace_ctxwake_raw(iter, 0);
952 }
953 
954 static enum print_line_t trace_wake_raw(struct trace_iterator *iter, int flags,
955 					struct trace_event *event)
956 {
957 	return trace_ctxwake_raw(iter, '+');
958 }
959 
960 
961 static int trace_ctxwake_hex(struct trace_iterator *iter, char S)
962 {
963 	struct ctx_switch_entry *field;
964 	struct trace_seq *s = &iter->seq;
965 	int T;
966 
967 	trace_assign_type(field, iter->ent);
968 
969 	if (!S)
970 		S = task_state_char(field->prev_state);
971 	T = task_state_char(field->next_state);
972 
973 	SEQ_PUT_HEX_FIELD(s, field->prev_pid);
974 	SEQ_PUT_HEX_FIELD(s, field->prev_prio);
975 	SEQ_PUT_HEX_FIELD(s, S);
976 	SEQ_PUT_HEX_FIELD(s, field->next_cpu);
977 	SEQ_PUT_HEX_FIELD(s, field->next_pid);
978 	SEQ_PUT_HEX_FIELD(s, field->next_prio);
979 	SEQ_PUT_HEX_FIELD(s, T);
980 
981 	return trace_handle_return(s);
982 }
983 
984 static enum print_line_t trace_ctx_hex(struct trace_iterator *iter, int flags,
985 				       struct trace_event *event)
986 {
987 	return trace_ctxwake_hex(iter, 0);
988 }
989 
990 static enum print_line_t trace_wake_hex(struct trace_iterator *iter, int flags,
991 					struct trace_event *event)
992 {
993 	return trace_ctxwake_hex(iter, '+');
994 }
995 
996 static enum print_line_t trace_ctxwake_bin(struct trace_iterator *iter,
997 					   int flags, struct trace_event *event)
998 {
999 	struct ctx_switch_entry *field;
1000 	struct trace_seq *s = &iter->seq;
1001 
1002 	trace_assign_type(field, iter->ent);
1003 
1004 	SEQ_PUT_FIELD(s, field->prev_pid);
1005 	SEQ_PUT_FIELD(s, field->prev_prio);
1006 	SEQ_PUT_FIELD(s, field->prev_state);
1007 	SEQ_PUT_FIELD(s, field->next_cpu);
1008 	SEQ_PUT_FIELD(s, field->next_pid);
1009 	SEQ_PUT_FIELD(s, field->next_prio);
1010 	SEQ_PUT_FIELD(s, field->next_state);
1011 
1012 	return trace_handle_return(s);
1013 }
1014 
1015 static struct trace_event_functions trace_ctx_funcs = {
1016 	.trace		= trace_ctx_print,
1017 	.raw		= trace_ctx_raw,
1018 	.hex		= trace_ctx_hex,
1019 	.binary		= trace_ctxwake_bin,
1020 };
1021 
1022 static struct trace_event trace_ctx_event = {
1023 	.type		= TRACE_CTX,
1024 	.funcs		= &trace_ctx_funcs,
1025 };
1026 
1027 static struct trace_event_functions trace_wake_funcs = {
1028 	.trace		= trace_wake_print,
1029 	.raw		= trace_wake_raw,
1030 	.hex		= trace_wake_hex,
1031 	.binary		= trace_ctxwake_bin,
1032 };
1033 
1034 static struct trace_event trace_wake_event = {
1035 	.type		= TRACE_WAKE,
1036 	.funcs		= &trace_wake_funcs,
1037 };
1038 
1039 /* TRACE_STACK */
1040 
1041 static enum print_line_t trace_stack_print(struct trace_iterator *iter,
1042 					   int flags, struct trace_event *event)
1043 {
1044 	struct stack_entry *field;
1045 	struct trace_seq *s = &iter->seq;
1046 	unsigned long *p;
1047 	unsigned long *end;
1048 
1049 	trace_assign_type(field, iter->ent);
1050 	end = (unsigned long *)((long)iter->ent + iter->ent_size);
1051 
1052 	trace_seq_puts(s, "<stack trace>\n");
1053 
1054 	for (p = field->caller; p && *p != ULONG_MAX && p < end; p++) {
1055 
1056 		if (trace_seq_has_overflowed(s))
1057 			break;
1058 
1059 		trace_seq_puts(s, " => ");
1060 		seq_print_ip_sym(s, *p, flags);
1061 		trace_seq_putc(s, '\n');
1062 	}
1063 
1064 	return trace_handle_return(s);
1065 }
1066 
1067 static struct trace_event_functions trace_stack_funcs = {
1068 	.trace		= trace_stack_print,
1069 };
1070 
1071 static struct trace_event trace_stack_event = {
1072 	.type		= TRACE_STACK,
1073 	.funcs		= &trace_stack_funcs,
1074 };
1075 
1076 /* TRACE_USER_STACK */
1077 static enum print_line_t trace_user_stack_print(struct trace_iterator *iter,
1078 						int flags, struct trace_event *event)
1079 {
1080 	struct userstack_entry *field;
1081 	struct trace_seq *s = &iter->seq;
1082 
1083 	trace_assign_type(field, iter->ent);
1084 
1085 	trace_seq_puts(s, "<user stack trace>\n");
1086 	seq_print_userip_objs(field, s, flags);
1087 
1088 	return trace_handle_return(s);
1089 }
1090 
1091 static struct trace_event_functions trace_user_stack_funcs = {
1092 	.trace		= trace_user_stack_print,
1093 };
1094 
1095 static struct trace_event trace_user_stack_event = {
1096 	.type		= TRACE_USER_STACK,
1097 	.funcs		= &trace_user_stack_funcs,
1098 };
1099 
1100 /* TRACE_BPUTS */
1101 static enum print_line_t
1102 trace_bputs_print(struct trace_iterator *iter, int flags,
1103 		   struct trace_event *event)
1104 {
1105 	struct trace_entry *entry = iter->ent;
1106 	struct trace_seq *s = &iter->seq;
1107 	struct bputs_entry *field;
1108 
1109 	trace_assign_type(field, entry);
1110 
1111 	seq_print_ip_sym(s, field->ip, flags);
1112 	trace_seq_puts(s, ": ");
1113 	trace_seq_puts(s, field->str);
1114 
1115 	return trace_handle_return(s);
1116 }
1117 
1118 
1119 static enum print_line_t
1120 trace_bputs_raw(struct trace_iterator *iter, int flags,
1121 		struct trace_event *event)
1122 {
1123 	struct bputs_entry *field;
1124 	struct trace_seq *s = &iter->seq;
1125 
1126 	trace_assign_type(field, iter->ent);
1127 
1128 	trace_seq_printf(s, ": %lx : ", field->ip);
1129 	trace_seq_puts(s, field->str);
1130 
1131 	return trace_handle_return(s);
1132 }
1133 
1134 static struct trace_event_functions trace_bputs_funcs = {
1135 	.trace		= trace_bputs_print,
1136 	.raw		= trace_bputs_raw,
1137 };
1138 
1139 static struct trace_event trace_bputs_event = {
1140 	.type		= TRACE_BPUTS,
1141 	.funcs		= &trace_bputs_funcs,
1142 };
1143 
1144 /* TRACE_BPRINT */
1145 static enum print_line_t
1146 trace_bprint_print(struct trace_iterator *iter, int flags,
1147 		   struct trace_event *event)
1148 {
1149 	struct trace_entry *entry = iter->ent;
1150 	struct trace_seq *s = &iter->seq;
1151 	struct bprint_entry *field;
1152 
1153 	trace_assign_type(field, entry);
1154 
1155 	seq_print_ip_sym(s, field->ip, flags);
1156 	trace_seq_puts(s, ": ");
1157 	trace_seq_bprintf(s, field->fmt, field->buf);
1158 
1159 	return trace_handle_return(s);
1160 }
1161 
1162 
1163 static enum print_line_t
1164 trace_bprint_raw(struct trace_iterator *iter, int flags,
1165 		 struct trace_event *event)
1166 {
1167 	struct bprint_entry *field;
1168 	struct trace_seq *s = &iter->seq;
1169 
1170 	trace_assign_type(field, iter->ent);
1171 
1172 	trace_seq_printf(s, ": %lx : ", field->ip);
1173 	trace_seq_bprintf(s, field->fmt, field->buf);
1174 
1175 	return trace_handle_return(s);
1176 }
1177 
1178 static struct trace_event_functions trace_bprint_funcs = {
1179 	.trace		= trace_bprint_print,
1180 	.raw		= trace_bprint_raw,
1181 };
1182 
1183 static struct trace_event trace_bprint_event = {
1184 	.type		= TRACE_BPRINT,
1185 	.funcs		= &trace_bprint_funcs,
1186 };
1187 
1188 /* TRACE_PRINT */
1189 static enum print_line_t trace_print_print(struct trace_iterator *iter,
1190 					   int flags, struct trace_event *event)
1191 {
1192 	struct print_entry *field;
1193 	struct trace_seq *s = &iter->seq;
1194 
1195 	trace_assign_type(field, iter->ent);
1196 
1197 	seq_print_ip_sym(s, field->ip, flags);
1198 	trace_seq_printf(s, ": %s", field->buf);
1199 
1200 	return trace_handle_return(s);
1201 }
1202 
1203 static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags,
1204 					 struct trace_event *event)
1205 {
1206 	struct print_entry *field;
1207 
1208 	trace_assign_type(field, iter->ent);
1209 
1210 	trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf);
1211 
1212 	return trace_handle_return(&iter->seq);
1213 }
1214 
1215 static struct trace_event_functions trace_print_funcs = {
1216 	.trace		= trace_print_print,
1217 	.raw		= trace_print_raw,
1218 };
1219 
1220 static struct trace_event trace_print_event = {
1221 	.type	 	= TRACE_PRINT,
1222 	.funcs		= &trace_print_funcs,
1223 };
1224 
1225 
1226 static struct trace_event *events[] __initdata = {
1227 	&trace_fn_event,
1228 	&trace_ctx_event,
1229 	&trace_wake_event,
1230 	&trace_stack_event,
1231 	&trace_user_stack_event,
1232 	&trace_bputs_event,
1233 	&trace_bprint_event,
1234 	&trace_print_event,
1235 	NULL
1236 };
1237 
1238 __init static int init_events(void)
1239 {
1240 	struct trace_event *event;
1241 	int i, ret;
1242 
1243 	for (i = 0; events[i]; i++) {
1244 		event = events[i];
1245 
1246 		ret = register_trace_event(event);
1247 		if (!ret) {
1248 			printk(KERN_WARNING "event %d failed to register\n",
1249 			       event->type);
1250 			WARN_ON_ONCE(1);
1251 		}
1252 	}
1253 
1254 	return 0;
1255 }
1256 early_initcall(init_events);
1257