xref: /openbmc/linux/kernel/trace/trace_output.c (revision 276e552e)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * trace_output.c
4  *
5  * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
6  *
7  */
8 #include <linux/module.h>
9 #include <linux/mutex.h>
10 #include <linux/ftrace.h>
11 #include <linux/sched/clock.h>
12 #include <linux/sched/mm.h>
13 
14 #include "trace_output.h"
15 
16 /* must be a power of 2 */
17 #define EVENT_HASHSIZE	128
18 
19 DECLARE_RWSEM(trace_event_sem);
20 
21 static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;
22 
23 static int next_event_type = __TRACE_LAST_TYPE;
24 
25 enum print_line_t trace_print_bputs_msg_only(struct trace_iterator *iter)
26 {
27 	struct trace_seq *s = &iter->seq;
28 	struct trace_entry *entry = iter->ent;
29 	struct bputs_entry *field;
30 
31 	trace_assign_type(field, entry);
32 
33 	trace_seq_puts(s, field->str);
34 
35 	return trace_handle_return(s);
36 }
37 
38 enum print_line_t trace_print_bprintk_msg_only(struct trace_iterator *iter)
39 {
40 	struct trace_seq *s = &iter->seq;
41 	struct trace_entry *entry = iter->ent;
42 	struct bprint_entry *field;
43 
44 	trace_assign_type(field, entry);
45 
46 	trace_seq_bprintf(s, field->fmt, field->buf);
47 
48 	return trace_handle_return(s);
49 }
50 
51 enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter)
52 {
53 	struct trace_seq *s = &iter->seq;
54 	struct trace_entry *entry = iter->ent;
55 	struct print_entry *field;
56 
57 	trace_assign_type(field, entry);
58 
59 	trace_seq_puts(s, field->buf);
60 
61 	return trace_handle_return(s);
62 }
63 
64 const char *
65 trace_print_flags_seq(struct trace_seq *p, const char *delim,
66 		      unsigned long flags,
67 		      const struct trace_print_flags *flag_array)
68 {
69 	unsigned long mask;
70 	const char *str;
71 	const char *ret = trace_seq_buffer_ptr(p);
72 	int i, first = 1;
73 
74 	for (i = 0;  flag_array[i].name && flags; i++) {
75 
76 		mask = flag_array[i].mask;
77 		if ((flags & mask) != mask)
78 			continue;
79 
80 		str = flag_array[i].name;
81 		flags &= ~mask;
82 		if (!first && delim)
83 			trace_seq_puts(p, delim);
84 		else
85 			first = 0;
86 		trace_seq_puts(p, str);
87 	}
88 
89 	/* check for left over flags */
90 	if (flags) {
91 		if (!first && delim)
92 			trace_seq_puts(p, delim);
93 		trace_seq_printf(p, "0x%lx", flags);
94 	}
95 
96 	trace_seq_putc(p, 0);
97 
98 	return ret;
99 }
100 EXPORT_SYMBOL(trace_print_flags_seq);
101 
102 const char *
103 trace_print_symbols_seq(struct trace_seq *p, unsigned long val,
104 			const struct trace_print_flags *symbol_array)
105 {
106 	int i;
107 	const char *ret = trace_seq_buffer_ptr(p);
108 
109 	for (i = 0;  symbol_array[i].name; i++) {
110 
111 		if (val != symbol_array[i].mask)
112 			continue;
113 
114 		trace_seq_puts(p, symbol_array[i].name);
115 		break;
116 	}
117 
118 	if (ret == (const char *)(trace_seq_buffer_ptr(p)))
119 		trace_seq_printf(p, "0x%lx", val);
120 
121 	trace_seq_putc(p, 0);
122 
123 	return ret;
124 }
125 EXPORT_SYMBOL(trace_print_symbols_seq);
126 
127 #if BITS_PER_LONG == 32
128 const char *
129 trace_print_flags_seq_u64(struct trace_seq *p, const char *delim,
130 		      unsigned long long flags,
131 		      const struct trace_print_flags_u64 *flag_array)
132 {
133 	unsigned long long mask;
134 	const char *str;
135 	const char *ret = trace_seq_buffer_ptr(p);
136 	int i, first = 1;
137 
138 	for (i = 0;  flag_array[i].name && flags; i++) {
139 
140 		mask = flag_array[i].mask;
141 		if ((flags & mask) != mask)
142 			continue;
143 
144 		str = flag_array[i].name;
145 		flags &= ~mask;
146 		if (!first && delim)
147 			trace_seq_puts(p, delim);
148 		else
149 			first = 0;
150 		trace_seq_puts(p, str);
151 	}
152 
153 	/* check for left over flags */
154 	if (flags) {
155 		if (!first && delim)
156 			trace_seq_puts(p, delim);
157 		trace_seq_printf(p, "0x%llx", flags);
158 	}
159 
160 	trace_seq_putc(p, 0);
161 
162 	return ret;
163 }
164 EXPORT_SYMBOL(trace_print_flags_seq_u64);
165 
166 const char *
167 trace_print_symbols_seq_u64(struct trace_seq *p, unsigned long long val,
168 			 const struct trace_print_flags_u64 *symbol_array)
169 {
170 	int i;
171 	const char *ret = trace_seq_buffer_ptr(p);
172 
173 	for (i = 0;  symbol_array[i].name; i++) {
174 
175 		if (val != symbol_array[i].mask)
176 			continue;
177 
178 		trace_seq_puts(p, symbol_array[i].name);
179 		break;
180 	}
181 
182 	if (ret == (const char *)(trace_seq_buffer_ptr(p)))
183 		trace_seq_printf(p, "0x%llx", val);
184 
185 	trace_seq_putc(p, 0);
186 
187 	return ret;
188 }
189 EXPORT_SYMBOL(trace_print_symbols_seq_u64);
190 #endif
191 
192 const char *
193 trace_print_bitmask_seq(struct trace_seq *p, void *bitmask_ptr,
194 			unsigned int bitmask_size)
195 {
196 	const char *ret = trace_seq_buffer_ptr(p);
197 
198 	trace_seq_bitmask(p, bitmask_ptr, bitmask_size * 8);
199 	trace_seq_putc(p, 0);
200 
201 	return ret;
202 }
203 EXPORT_SYMBOL_GPL(trace_print_bitmask_seq);
204 
205 /**
206  * trace_print_hex_seq - print buffer as hex sequence
207  * @p: trace seq struct to write to
208  * @buf: The buffer to print
209  * @buf_len: Length of @buf in bytes
210  * @concatenate: Print @buf as single hex string or with spacing
211  *
212  * Prints the passed buffer as a hex sequence either as a whole,
213  * single hex string if @concatenate is true or with spacing after
214  * each byte in case @concatenate is false.
215  */
216 const char *
217 trace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len,
218 		    bool concatenate)
219 {
220 	int i;
221 	const char *ret = trace_seq_buffer_ptr(p);
222 	const char *fmt = concatenate ? "%*phN" : "%*ph";
223 
224 	for (i = 0; i < buf_len; i += 16)
225 		trace_seq_printf(p, fmt, min(buf_len - i, 16), &buf[i]);
226 	trace_seq_putc(p, 0);
227 
228 	return ret;
229 }
230 EXPORT_SYMBOL(trace_print_hex_seq);
231 
232 const char *
233 trace_print_array_seq(struct trace_seq *p, const void *buf, int count,
234 		      size_t el_size)
235 {
236 	const char *ret = trace_seq_buffer_ptr(p);
237 	const char *prefix = "";
238 	void *ptr = (void *)buf;
239 	size_t buf_len = count * el_size;
240 
241 	trace_seq_putc(p, '{');
242 
243 	while (ptr < buf + buf_len) {
244 		switch (el_size) {
245 		case 1:
246 			trace_seq_printf(p, "%s0x%x", prefix,
247 					 *(u8 *)ptr);
248 			break;
249 		case 2:
250 			trace_seq_printf(p, "%s0x%x", prefix,
251 					 *(u16 *)ptr);
252 			break;
253 		case 4:
254 			trace_seq_printf(p, "%s0x%x", prefix,
255 					 *(u32 *)ptr);
256 			break;
257 		case 8:
258 			trace_seq_printf(p, "%s0x%llx", prefix,
259 					 *(u64 *)ptr);
260 			break;
261 		default:
262 			trace_seq_printf(p, "BAD SIZE:%zu 0x%x", el_size,
263 					 *(u8 *)ptr);
264 			el_size = 1;
265 		}
266 		prefix = ",";
267 		ptr += el_size;
268 	}
269 
270 	trace_seq_putc(p, '}');
271 	trace_seq_putc(p, 0);
272 
273 	return ret;
274 }
275 EXPORT_SYMBOL(trace_print_array_seq);
276 
277 const char *
278 trace_print_hex_dump_seq(struct trace_seq *p, const char *prefix_str,
279 			 int prefix_type, int rowsize, int groupsize,
280 			 const void *buf, size_t len, bool ascii)
281 {
282 	const char *ret = trace_seq_buffer_ptr(p);
283 
284 	trace_seq_putc(p, '\n');
285 	trace_seq_hex_dump(p, prefix_str, prefix_type,
286 			   rowsize, groupsize, buf, len, ascii);
287 	trace_seq_putc(p, 0);
288 	return ret;
289 }
290 EXPORT_SYMBOL(trace_print_hex_dump_seq);
291 
292 int trace_raw_output_prep(struct trace_iterator *iter,
293 			  struct trace_event *trace_event)
294 {
295 	struct trace_event_call *event;
296 	struct trace_seq *s = &iter->seq;
297 	struct trace_seq *p = &iter->tmp_seq;
298 	struct trace_entry *entry;
299 
300 	event = container_of(trace_event, struct trace_event_call, event);
301 	entry = iter->ent;
302 
303 	if (entry->type != event->event.type) {
304 		WARN_ON_ONCE(1);
305 		return TRACE_TYPE_UNHANDLED;
306 	}
307 
308 	trace_seq_init(p);
309 	trace_seq_printf(s, "%s: ", trace_event_name(event));
310 
311 	return trace_handle_return(s);
312 }
313 EXPORT_SYMBOL(trace_raw_output_prep);
314 
315 void trace_event_printf(struct trace_iterator *iter, const char *fmt, ...)
316 {
317 	va_list ap;
318 
319 	va_start(ap, fmt);
320 	trace_check_vprintf(iter, trace_event_format(iter, fmt), ap);
321 	va_end(ap);
322 }
323 EXPORT_SYMBOL(trace_event_printf);
324 
325 static int trace_output_raw(struct trace_iterator *iter, char *name,
326 			    char *fmt, va_list ap)
327 {
328 	struct trace_seq *s = &iter->seq;
329 
330 	trace_seq_printf(s, "%s: ", name);
331 	trace_seq_vprintf(s, trace_event_format(iter, fmt), ap);
332 
333 	return trace_handle_return(s);
334 }
335 
336 int trace_output_call(struct trace_iterator *iter, char *name, char *fmt, ...)
337 {
338 	va_list ap;
339 	int ret;
340 
341 	va_start(ap, fmt);
342 	ret = trace_output_raw(iter, name, fmt, ap);
343 	va_end(ap);
344 
345 	return ret;
346 }
347 EXPORT_SYMBOL_GPL(trace_output_call);
348 
349 #ifdef CONFIG_KRETPROBES
350 static inline const char *kretprobed(const char *name)
351 {
352 	static const char tramp_name[] = "kretprobe_trampoline";
353 	int size = sizeof(tramp_name);
354 
355 	if (strncmp(tramp_name, name, size) == 0)
356 		return "[unknown/kretprobe'd]";
357 	return name;
358 }
359 #else
360 static inline const char *kretprobed(const char *name)
361 {
362 	return name;
363 }
364 #endif /* CONFIG_KRETPROBES */
365 
366 void
367 trace_seq_print_sym(struct trace_seq *s, unsigned long address, bool offset)
368 {
369 #ifdef CONFIG_KALLSYMS
370 	char str[KSYM_SYMBOL_LEN];
371 	const char *name;
372 
373 	if (offset)
374 		sprint_symbol(str, address);
375 	else
376 		kallsyms_lookup(address, NULL, NULL, NULL, str);
377 	name = kretprobed(str);
378 
379 	if (name && strlen(name)) {
380 		trace_seq_puts(s, name);
381 		return;
382 	}
383 #endif
384 	trace_seq_printf(s, "0x%08lx", address);
385 }
386 
387 #ifndef CONFIG_64BIT
388 # define IP_FMT "%08lx"
389 #else
390 # define IP_FMT "%016lx"
391 #endif
392 
393 static int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
394 			     unsigned long ip, unsigned long sym_flags)
395 {
396 	struct file *file = NULL;
397 	unsigned long vmstart = 0;
398 	int ret = 1;
399 
400 	if (s->full)
401 		return 0;
402 
403 	if (mm) {
404 		const struct vm_area_struct *vma;
405 
406 		mmap_read_lock(mm);
407 		vma = find_vma(mm, ip);
408 		if (vma) {
409 			file = vma->vm_file;
410 			vmstart = vma->vm_start;
411 		}
412 		if (file) {
413 			ret = trace_seq_path(s, &file->f_path);
414 			if (ret)
415 				trace_seq_printf(s, "[+0x%lx]",
416 						 ip - vmstart);
417 		}
418 		mmap_read_unlock(mm);
419 	}
420 	if (ret && ((sym_flags & TRACE_ITER_SYM_ADDR) || !file))
421 		trace_seq_printf(s, " <" IP_FMT ">", ip);
422 	return !trace_seq_has_overflowed(s);
423 }
424 
425 int
426 seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
427 {
428 	if (!ip) {
429 		trace_seq_putc(s, '0');
430 		goto out;
431 	}
432 
433 	trace_seq_print_sym(s, ip, sym_flags & TRACE_ITER_SYM_OFFSET);
434 
435 	if (sym_flags & TRACE_ITER_SYM_ADDR)
436 		trace_seq_printf(s, " <" IP_FMT ">", ip);
437 
438  out:
439 	return !trace_seq_has_overflowed(s);
440 }
441 
442 /**
443  * trace_print_lat_fmt - print the irq, preempt and lockdep fields
444  * @s: trace seq struct to write to
445  * @entry: The trace entry field from the ring buffer
446  *
447  * Prints the generic fields of irqs off, in hard or softirq, preempt
448  * count.
449  */
450 int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
451 {
452 	char hardsoft_irq;
453 	char need_resched;
454 	char irqs_off;
455 	int hardirq;
456 	int softirq;
457 	int nmi;
458 
459 	nmi = entry->flags & TRACE_FLAG_NMI;
460 	hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
461 	softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
462 
463 	irqs_off =
464 		(entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
465 		(entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' :
466 		'.';
467 
468 	switch (entry->flags & (TRACE_FLAG_NEED_RESCHED |
469 				TRACE_FLAG_PREEMPT_RESCHED)) {
470 	case TRACE_FLAG_NEED_RESCHED | TRACE_FLAG_PREEMPT_RESCHED:
471 		need_resched = 'N';
472 		break;
473 	case TRACE_FLAG_NEED_RESCHED:
474 		need_resched = 'n';
475 		break;
476 	case TRACE_FLAG_PREEMPT_RESCHED:
477 		need_resched = 'p';
478 		break;
479 	default:
480 		need_resched = '.';
481 		break;
482 	}
483 
484 	hardsoft_irq =
485 		(nmi && hardirq)     ? 'Z' :
486 		nmi                  ? 'z' :
487 		(hardirq && softirq) ? 'H' :
488 		hardirq              ? 'h' :
489 		softirq              ? 's' :
490 		                       '.' ;
491 
492 	trace_seq_printf(s, "%c%c%c",
493 			 irqs_off, need_resched, hardsoft_irq);
494 
495 	if (entry->preempt_count)
496 		trace_seq_printf(s, "%x", entry->preempt_count);
497 	else
498 		trace_seq_putc(s, '.');
499 
500 	return !trace_seq_has_overflowed(s);
501 }
502 
503 static int
504 lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
505 {
506 	char comm[TASK_COMM_LEN];
507 
508 	trace_find_cmdline(entry->pid, comm);
509 
510 	trace_seq_printf(s, "%8.8s-%-7d %3d",
511 			 comm, entry->pid, cpu);
512 
513 	return trace_print_lat_fmt(s, entry);
514 }
515 
516 #undef MARK
517 #define MARK(v, s) {.val = v, .sym = s}
518 /* trace overhead mark */
519 static const struct trace_mark {
520 	unsigned long long	val; /* unit: nsec */
521 	char			sym;
522 } mark[] = {
523 	MARK(1000000000ULL	, '$'), /* 1 sec */
524 	MARK(100000000ULL	, '@'), /* 100 msec */
525 	MARK(10000000ULL	, '*'), /* 10 msec */
526 	MARK(1000000ULL		, '#'), /* 1000 usecs */
527 	MARK(100000ULL		, '!'), /* 100 usecs */
528 	MARK(10000ULL		, '+'), /* 10 usecs */
529 };
530 #undef MARK
531 
532 char trace_find_mark(unsigned long long d)
533 {
534 	int i;
535 	int size = ARRAY_SIZE(mark);
536 
537 	for (i = 0; i < size; i++) {
538 		if (d > mark[i].val)
539 			break;
540 	}
541 
542 	return (i == size) ? ' ' : mark[i].sym;
543 }
544 
545 static int
546 lat_print_timestamp(struct trace_iterator *iter, u64 next_ts)
547 {
548 	struct trace_array *tr = iter->tr;
549 	unsigned long verbose = tr->trace_flags & TRACE_ITER_VERBOSE;
550 	unsigned long in_ns = iter->iter_flags & TRACE_FILE_TIME_IN_NS;
551 	unsigned long long abs_ts = iter->ts - iter->array_buffer->time_start;
552 	unsigned long long rel_ts = next_ts - iter->ts;
553 	struct trace_seq *s = &iter->seq;
554 
555 	if (in_ns) {
556 		abs_ts = ns2usecs(abs_ts);
557 		rel_ts = ns2usecs(rel_ts);
558 	}
559 
560 	if (verbose && in_ns) {
561 		unsigned long abs_usec = do_div(abs_ts, USEC_PER_MSEC);
562 		unsigned long abs_msec = (unsigned long)abs_ts;
563 		unsigned long rel_usec = do_div(rel_ts, USEC_PER_MSEC);
564 		unsigned long rel_msec = (unsigned long)rel_ts;
565 
566 		trace_seq_printf(
567 			s, "[%08llx] %ld.%03ldms (+%ld.%03ldms): ",
568 			ns2usecs(iter->ts),
569 			abs_msec, abs_usec,
570 			rel_msec, rel_usec);
571 
572 	} else if (verbose && !in_ns) {
573 		trace_seq_printf(
574 			s, "[%016llx] %lld (+%lld): ",
575 			iter->ts, abs_ts, rel_ts);
576 
577 	} else if (!verbose && in_ns) {
578 		trace_seq_printf(
579 			s, " %4lldus%c: ",
580 			abs_ts,
581 			trace_find_mark(rel_ts * NSEC_PER_USEC));
582 
583 	} else { /* !verbose && !in_ns */
584 		trace_seq_printf(s, " %4lld: ", abs_ts);
585 	}
586 
587 	return !trace_seq_has_overflowed(s);
588 }
589 
590 static void trace_print_time(struct trace_seq *s, struct trace_iterator *iter,
591 			     unsigned long long ts)
592 {
593 	unsigned long secs, usec_rem;
594 	unsigned long long t;
595 
596 	if (iter->iter_flags & TRACE_FILE_TIME_IN_NS) {
597 		t = ns2usecs(ts);
598 		usec_rem = do_div(t, USEC_PER_SEC);
599 		secs = (unsigned long)t;
600 		trace_seq_printf(s, " %5lu.%06lu", secs, usec_rem);
601 	} else
602 		trace_seq_printf(s, " %12llu", ts);
603 }
604 
605 int trace_print_context(struct trace_iterator *iter)
606 {
607 	struct trace_array *tr = iter->tr;
608 	struct trace_seq *s = &iter->seq;
609 	struct trace_entry *entry = iter->ent;
610 	char comm[TASK_COMM_LEN];
611 
612 	trace_find_cmdline(entry->pid, comm);
613 
614 	trace_seq_printf(s, "%16s-%-7d ", comm, entry->pid);
615 
616 	if (tr->trace_flags & TRACE_ITER_RECORD_TGID) {
617 		unsigned int tgid = trace_find_tgid(entry->pid);
618 
619 		if (!tgid)
620 			trace_seq_printf(s, "(-------) ");
621 		else
622 			trace_seq_printf(s, "(%7d) ", tgid);
623 	}
624 
625 	trace_seq_printf(s, "[%03d] ", iter->cpu);
626 
627 	if (tr->trace_flags & TRACE_ITER_IRQ_INFO)
628 		trace_print_lat_fmt(s, entry);
629 
630 	trace_print_time(s, iter, iter->ts);
631 	trace_seq_puts(s, ": ");
632 
633 	return !trace_seq_has_overflowed(s);
634 }
635 
636 int trace_print_lat_context(struct trace_iterator *iter)
637 {
638 	struct trace_entry *entry, *next_entry;
639 	struct trace_array *tr = iter->tr;
640 	struct trace_seq *s = &iter->seq;
641 	unsigned long verbose = (tr->trace_flags & TRACE_ITER_VERBOSE);
642 	u64 next_ts;
643 
644 	next_entry = trace_find_next_entry(iter, NULL, &next_ts);
645 	if (!next_entry)
646 		next_ts = iter->ts;
647 
648 	/* trace_find_next_entry() may change iter->ent */
649 	entry = iter->ent;
650 
651 	if (verbose) {
652 		char comm[TASK_COMM_LEN];
653 
654 		trace_find_cmdline(entry->pid, comm);
655 
656 		trace_seq_printf(
657 			s, "%16s %7d %3d %d %08x %08lx ",
658 			comm, entry->pid, iter->cpu, entry->flags,
659 			entry->preempt_count, iter->idx);
660 	} else {
661 		lat_print_generic(s, entry, iter->cpu);
662 	}
663 
664 	lat_print_timestamp(iter, next_ts);
665 
666 	return !trace_seq_has_overflowed(s);
667 }
668 
669 /**
670  * ftrace_find_event - find a registered event
671  * @type: the type of event to look for
672  *
673  * Returns an event of type @type otherwise NULL
674  * Called with trace_event_read_lock() held.
675  */
676 struct trace_event *ftrace_find_event(int type)
677 {
678 	struct trace_event *event;
679 	unsigned key;
680 
681 	key = type & (EVENT_HASHSIZE - 1);
682 
683 	hlist_for_each_entry(event, &event_hash[key], node) {
684 		if (event->type == type)
685 			return event;
686 	}
687 
688 	return NULL;
689 }
690 
691 static LIST_HEAD(ftrace_event_list);
692 
693 static int trace_search_list(struct list_head **list)
694 {
695 	struct trace_event *e;
696 	int next = __TRACE_LAST_TYPE;
697 
698 	if (list_empty(&ftrace_event_list)) {
699 		*list = &ftrace_event_list;
700 		return next;
701 	}
702 
703 	/*
704 	 * We used up all possible max events,
705 	 * lets see if somebody freed one.
706 	 */
707 	list_for_each_entry(e, &ftrace_event_list, list) {
708 		if (e->type != next)
709 			break;
710 		next++;
711 	}
712 
713 	/* Did we used up all 65 thousand events??? */
714 	if (next > TRACE_EVENT_TYPE_MAX)
715 		return 0;
716 
717 	*list = &e->list;
718 	return next;
719 }
720 
721 void trace_event_read_lock(void)
722 {
723 	down_read(&trace_event_sem);
724 }
725 
726 void trace_event_read_unlock(void)
727 {
728 	up_read(&trace_event_sem);
729 }
730 
731 /**
732  * register_trace_event - register output for an event type
733  * @event: the event type to register
734  *
735  * Event types are stored in a hash and this hash is used to
736  * find a way to print an event. If the @event->type is set
737  * then it will use that type, otherwise it will assign a
738  * type to use.
739  *
740  * If you assign your own type, please make sure it is added
741  * to the trace_type enum in trace.h, to avoid collisions
742  * with the dynamic types.
743  *
744  * Returns the event type number or zero on error.
745  */
746 int register_trace_event(struct trace_event *event)
747 {
748 	unsigned key;
749 	int ret = 0;
750 
751 	down_write(&trace_event_sem);
752 
753 	if (WARN_ON(!event))
754 		goto out;
755 
756 	if (WARN_ON(!event->funcs))
757 		goto out;
758 
759 	INIT_LIST_HEAD(&event->list);
760 
761 	if (!event->type) {
762 		struct list_head *list = NULL;
763 
764 		if (next_event_type > TRACE_EVENT_TYPE_MAX) {
765 
766 			event->type = trace_search_list(&list);
767 			if (!event->type)
768 				goto out;
769 
770 		} else {
771 
772 			event->type = next_event_type++;
773 			list = &ftrace_event_list;
774 		}
775 
776 		if (WARN_ON(ftrace_find_event(event->type)))
777 			goto out;
778 
779 		list_add_tail(&event->list, list);
780 
781 	} else if (event->type > __TRACE_LAST_TYPE) {
782 		printk(KERN_WARNING "Need to add type to trace.h\n");
783 		WARN_ON(1);
784 		goto out;
785 	} else {
786 		/* Is this event already used */
787 		if (ftrace_find_event(event->type))
788 			goto out;
789 	}
790 
791 	if (event->funcs->trace == NULL)
792 		event->funcs->trace = trace_nop_print;
793 	if (event->funcs->raw == NULL)
794 		event->funcs->raw = trace_nop_print;
795 	if (event->funcs->hex == NULL)
796 		event->funcs->hex = trace_nop_print;
797 	if (event->funcs->binary == NULL)
798 		event->funcs->binary = trace_nop_print;
799 
800 	key = event->type & (EVENT_HASHSIZE - 1);
801 
802 	hlist_add_head(&event->node, &event_hash[key]);
803 
804 	ret = event->type;
805  out:
806 	up_write(&trace_event_sem);
807 
808 	return ret;
809 }
810 EXPORT_SYMBOL_GPL(register_trace_event);
811 
812 /*
813  * Used by module code with the trace_event_sem held for write.
814  */
815 int __unregister_trace_event(struct trace_event *event)
816 {
817 	hlist_del(&event->node);
818 	list_del(&event->list);
819 	return 0;
820 }
821 
822 /**
823  * unregister_trace_event - remove a no longer used event
824  * @event: the event to remove
825  */
826 int unregister_trace_event(struct trace_event *event)
827 {
828 	down_write(&trace_event_sem);
829 	__unregister_trace_event(event);
830 	up_write(&trace_event_sem);
831 
832 	return 0;
833 }
834 EXPORT_SYMBOL_GPL(unregister_trace_event);
835 
836 /*
837  * Standard events
838  */
839 
840 enum print_line_t trace_nop_print(struct trace_iterator *iter, int flags,
841 				  struct trace_event *event)
842 {
843 	trace_seq_printf(&iter->seq, "type: %d\n", iter->ent->type);
844 
845 	return trace_handle_return(&iter->seq);
846 }
847 
848 static void print_fn_trace(struct trace_seq *s, unsigned long ip,
849 			   unsigned long parent_ip, int flags)
850 {
851 	seq_print_ip_sym(s, ip, flags);
852 
853 	if ((flags & TRACE_ITER_PRINT_PARENT) && parent_ip) {
854 		trace_seq_puts(s, " <-");
855 		seq_print_ip_sym(s, parent_ip, flags);
856 	}
857 }
858 
859 /* TRACE_FN */
860 static enum print_line_t trace_fn_trace(struct trace_iterator *iter, int flags,
861 					struct trace_event *event)
862 {
863 	struct ftrace_entry *field;
864 	struct trace_seq *s = &iter->seq;
865 
866 	trace_assign_type(field, iter->ent);
867 
868 	print_fn_trace(s, field->ip, field->parent_ip, flags);
869 	trace_seq_putc(s, '\n');
870 
871 	return trace_handle_return(s);
872 }
873 
874 static enum print_line_t trace_fn_raw(struct trace_iterator *iter, int flags,
875 				      struct trace_event *event)
876 {
877 	struct ftrace_entry *field;
878 
879 	trace_assign_type(field, iter->ent);
880 
881 	trace_seq_printf(&iter->seq, "%lx %lx\n",
882 			 field->ip,
883 			 field->parent_ip);
884 
885 	return trace_handle_return(&iter->seq);
886 }
887 
888 static enum print_line_t trace_fn_hex(struct trace_iterator *iter, int flags,
889 				      struct trace_event *event)
890 {
891 	struct ftrace_entry *field;
892 	struct trace_seq *s = &iter->seq;
893 
894 	trace_assign_type(field, iter->ent);
895 
896 	SEQ_PUT_HEX_FIELD(s, field->ip);
897 	SEQ_PUT_HEX_FIELD(s, field->parent_ip);
898 
899 	return trace_handle_return(s);
900 }
901 
902 static enum print_line_t trace_fn_bin(struct trace_iterator *iter, int flags,
903 				      struct trace_event *event)
904 {
905 	struct ftrace_entry *field;
906 	struct trace_seq *s = &iter->seq;
907 
908 	trace_assign_type(field, iter->ent);
909 
910 	SEQ_PUT_FIELD(s, field->ip);
911 	SEQ_PUT_FIELD(s, field->parent_ip);
912 
913 	return trace_handle_return(s);
914 }
915 
916 static struct trace_event_functions trace_fn_funcs = {
917 	.trace		= trace_fn_trace,
918 	.raw		= trace_fn_raw,
919 	.hex		= trace_fn_hex,
920 	.binary		= trace_fn_bin,
921 };
922 
923 static struct trace_event trace_fn_event = {
924 	.type		= TRACE_FN,
925 	.funcs		= &trace_fn_funcs,
926 };
927 
928 /* TRACE_CTX an TRACE_WAKE */
929 static enum print_line_t trace_ctxwake_print(struct trace_iterator *iter,
930 					     char *delim)
931 {
932 	struct ctx_switch_entry *field;
933 	char comm[TASK_COMM_LEN];
934 	int S, T;
935 
936 
937 	trace_assign_type(field, iter->ent);
938 
939 	T = task_index_to_char(field->next_state);
940 	S = task_index_to_char(field->prev_state);
941 	trace_find_cmdline(field->next_pid, comm);
942 	trace_seq_printf(&iter->seq,
943 			 " %7d:%3d:%c %s [%03d] %7d:%3d:%c %s\n",
944 			 field->prev_pid,
945 			 field->prev_prio,
946 			 S, delim,
947 			 field->next_cpu,
948 			 field->next_pid,
949 			 field->next_prio,
950 			 T, comm);
951 
952 	return trace_handle_return(&iter->seq);
953 }
954 
955 static enum print_line_t trace_ctx_print(struct trace_iterator *iter, int flags,
956 					 struct trace_event *event)
957 {
958 	return trace_ctxwake_print(iter, "==>");
959 }
960 
961 static enum print_line_t trace_wake_print(struct trace_iterator *iter,
962 					  int flags, struct trace_event *event)
963 {
964 	return trace_ctxwake_print(iter, "  +");
965 }
966 
967 static int trace_ctxwake_raw(struct trace_iterator *iter, char S)
968 {
969 	struct ctx_switch_entry *field;
970 	int T;
971 
972 	trace_assign_type(field, iter->ent);
973 
974 	if (!S)
975 		S = task_index_to_char(field->prev_state);
976 	T = task_index_to_char(field->next_state);
977 	trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
978 			 field->prev_pid,
979 			 field->prev_prio,
980 			 S,
981 			 field->next_cpu,
982 			 field->next_pid,
983 			 field->next_prio,
984 			 T);
985 
986 	return trace_handle_return(&iter->seq);
987 }
988 
989 static enum print_line_t trace_ctx_raw(struct trace_iterator *iter, int flags,
990 				       struct trace_event *event)
991 {
992 	return trace_ctxwake_raw(iter, 0);
993 }
994 
995 static enum print_line_t trace_wake_raw(struct trace_iterator *iter, int flags,
996 					struct trace_event *event)
997 {
998 	return trace_ctxwake_raw(iter, '+');
999 }
1000 
1001 
1002 static int trace_ctxwake_hex(struct trace_iterator *iter, char S)
1003 {
1004 	struct ctx_switch_entry *field;
1005 	struct trace_seq *s = &iter->seq;
1006 	int T;
1007 
1008 	trace_assign_type(field, iter->ent);
1009 
1010 	if (!S)
1011 		S = task_index_to_char(field->prev_state);
1012 	T = task_index_to_char(field->next_state);
1013 
1014 	SEQ_PUT_HEX_FIELD(s, field->prev_pid);
1015 	SEQ_PUT_HEX_FIELD(s, field->prev_prio);
1016 	SEQ_PUT_HEX_FIELD(s, S);
1017 	SEQ_PUT_HEX_FIELD(s, field->next_cpu);
1018 	SEQ_PUT_HEX_FIELD(s, field->next_pid);
1019 	SEQ_PUT_HEX_FIELD(s, field->next_prio);
1020 	SEQ_PUT_HEX_FIELD(s, T);
1021 
1022 	return trace_handle_return(s);
1023 }
1024 
1025 static enum print_line_t trace_ctx_hex(struct trace_iterator *iter, int flags,
1026 				       struct trace_event *event)
1027 {
1028 	return trace_ctxwake_hex(iter, 0);
1029 }
1030 
1031 static enum print_line_t trace_wake_hex(struct trace_iterator *iter, int flags,
1032 					struct trace_event *event)
1033 {
1034 	return trace_ctxwake_hex(iter, '+');
1035 }
1036 
1037 static enum print_line_t trace_ctxwake_bin(struct trace_iterator *iter,
1038 					   int flags, struct trace_event *event)
1039 {
1040 	struct ctx_switch_entry *field;
1041 	struct trace_seq *s = &iter->seq;
1042 
1043 	trace_assign_type(field, iter->ent);
1044 
1045 	SEQ_PUT_FIELD(s, field->prev_pid);
1046 	SEQ_PUT_FIELD(s, field->prev_prio);
1047 	SEQ_PUT_FIELD(s, field->prev_state);
1048 	SEQ_PUT_FIELD(s, field->next_cpu);
1049 	SEQ_PUT_FIELD(s, field->next_pid);
1050 	SEQ_PUT_FIELD(s, field->next_prio);
1051 	SEQ_PUT_FIELD(s, field->next_state);
1052 
1053 	return trace_handle_return(s);
1054 }
1055 
1056 static struct trace_event_functions trace_ctx_funcs = {
1057 	.trace		= trace_ctx_print,
1058 	.raw		= trace_ctx_raw,
1059 	.hex		= trace_ctx_hex,
1060 	.binary		= trace_ctxwake_bin,
1061 };
1062 
1063 static struct trace_event trace_ctx_event = {
1064 	.type		= TRACE_CTX,
1065 	.funcs		= &trace_ctx_funcs,
1066 };
1067 
1068 static struct trace_event_functions trace_wake_funcs = {
1069 	.trace		= trace_wake_print,
1070 	.raw		= trace_wake_raw,
1071 	.hex		= trace_wake_hex,
1072 	.binary		= trace_ctxwake_bin,
1073 };
1074 
1075 static struct trace_event trace_wake_event = {
1076 	.type		= TRACE_WAKE,
1077 	.funcs		= &trace_wake_funcs,
1078 };
1079 
1080 /* TRACE_STACK */
1081 
1082 static enum print_line_t trace_stack_print(struct trace_iterator *iter,
1083 					   int flags, struct trace_event *event)
1084 {
1085 	struct stack_entry *field;
1086 	struct trace_seq *s = &iter->seq;
1087 	unsigned long *p;
1088 	unsigned long *end;
1089 
1090 	trace_assign_type(field, iter->ent);
1091 	end = (unsigned long *)((long)iter->ent + iter->ent_size);
1092 
1093 	trace_seq_puts(s, "<stack trace>\n");
1094 
1095 	for (p = field->caller; p && p < end && *p != ULONG_MAX; p++) {
1096 
1097 		if (trace_seq_has_overflowed(s))
1098 			break;
1099 
1100 		trace_seq_puts(s, " => ");
1101 		seq_print_ip_sym(s, *p, flags);
1102 		trace_seq_putc(s, '\n');
1103 	}
1104 
1105 	return trace_handle_return(s);
1106 }
1107 
1108 static struct trace_event_functions trace_stack_funcs = {
1109 	.trace		= trace_stack_print,
1110 };
1111 
1112 static struct trace_event trace_stack_event = {
1113 	.type		= TRACE_STACK,
1114 	.funcs		= &trace_stack_funcs,
1115 };
1116 
1117 /* TRACE_USER_STACK */
1118 static enum print_line_t trace_user_stack_print(struct trace_iterator *iter,
1119 						int flags, struct trace_event *event)
1120 {
1121 	struct trace_array *tr = iter->tr;
1122 	struct userstack_entry *field;
1123 	struct trace_seq *s = &iter->seq;
1124 	struct mm_struct *mm = NULL;
1125 	unsigned int i;
1126 
1127 	trace_assign_type(field, iter->ent);
1128 
1129 	trace_seq_puts(s, "<user stack trace>\n");
1130 
1131 	if (tr->trace_flags & TRACE_ITER_SYM_USEROBJ) {
1132 		struct task_struct *task;
1133 		/*
1134 		 * we do the lookup on the thread group leader,
1135 		 * since individual threads might have already quit!
1136 		 */
1137 		rcu_read_lock();
1138 		task = find_task_by_vpid(field->tgid);
1139 		if (task)
1140 			mm = get_task_mm(task);
1141 		rcu_read_unlock();
1142 	}
1143 
1144 	for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
1145 		unsigned long ip = field->caller[i];
1146 
1147 		if (!ip || trace_seq_has_overflowed(s))
1148 			break;
1149 
1150 		trace_seq_puts(s, " => ");
1151 		seq_print_user_ip(s, mm, ip, flags);
1152 		trace_seq_putc(s, '\n');
1153 	}
1154 
1155 	if (mm)
1156 		mmput(mm);
1157 
1158 	return trace_handle_return(s);
1159 }
1160 
1161 static struct trace_event_functions trace_user_stack_funcs = {
1162 	.trace		= trace_user_stack_print,
1163 };
1164 
1165 static struct trace_event trace_user_stack_event = {
1166 	.type		= TRACE_USER_STACK,
1167 	.funcs		= &trace_user_stack_funcs,
1168 };
1169 
1170 /* TRACE_HWLAT */
1171 static enum print_line_t
1172 trace_hwlat_print(struct trace_iterator *iter, int flags,
1173 		  struct trace_event *event)
1174 {
1175 	struct trace_entry *entry = iter->ent;
1176 	struct trace_seq *s = &iter->seq;
1177 	struct hwlat_entry *field;
1178 
1179 	trace_assign_type(field, entry);
1180 
1181 	trace_seq_printf(s, "#%-5u inner/outer(us): %4llu/%-5llu ts:%lld.%09ld count:%d",
1182 			 field->seqnum,
1183 			 field->duration,
1184 			 field->outer_duration,
1185 			 (long long)field->timestamp.tv_sec,
1186 			 field->timestamp.tv_nsec, field->count);
1187 
1188 	if (field->nmi_count) {
1189 		/*
1190 		 * The generic sched_clock() is not NMI safe, thus
1191 		 * we only record the count and not the time.
1192 		 */
1193 		if (!IS_ENABLED(CONFIG_GENERIC_SCHED_CLOCK))
1194 			trace_seq_printf(s, " nmi-total:%llu",
1195 					 field->nmi_total_ts);
1196 		trace_seq_printf(s, " nmi-count:%u",
1197 				 field->nmi_count);
1198 	}
1199 
1200 	trace_seq_putc(s, '\n');
1201 
1202 	return trace_handle_return(s);
1203 }
1204 
1205 
1206 static enum print_line_t
1207 trace_hwlat_raw(struct trace_iterator *iter, int flags,
1208 		struct trace_event *event)
1209 {
1210 	struct hwlat_entry *field;
1211 	struct trace_seq *s = &iter->seq;
1212 
1213 	trace_assign_type(field, iter->ent);
1214 
1215 	trace_seq_printf(s, "%llu %lld %lld %09ld %u\n",
1216 			 field->duration,
1217 			 field->outer_duration,
1218 			 (long long)field->timestamp.tv_sec,
1219 			 field->timestamp.tv_nsec,
1220 			 field->seqnum);
1221 
1222 	return trace_handle_return(s);
1223 }
1224 
1225 static struct trace_event_functions trace_hwlat_funcs = {
1226 	.trace		= trace_hwlat_print,
1227 	.raw		= trace_hwlat_raw,
1228 };
1229 
1230 static struct trace_event trace_hwlat_event = {
1231 	.type		= TRACE_HWLAT,
1232 	.funcs		= &trace_hwlat_funcs,
1233 };
1234 
1235 /* TRACE_BPUTS */
1236 static enum print_line_t
1237 trace_bputs_print(struct trace_iterator *iter, int flags,
1238 		   struct trace_event *event)
1239 {
1240 	struct trace_entry *entry = iter->ent;
1241 	struct trace_seq *s = &iter->seq;
1242 	struct bputs_entry *field;
1243 
1244 	trace_assign_type(field, entry);
1245 
1246 	seq_print_ip_sym(s, field->ip, flags);
1247 	trace_seq_puts(s, ": ");
1248 	trace_seq_puts(s, field->str);
1249 
1250 	return trace_handle_return(s);
1251 }
1252 
1253 
1254 static enum print_line_t
1255 trace_bputs_raw(struct trace_iterator *iter, int flags,
1256 		struct trace_event *event)
1257 {
1258 	struct bputs_entry *field;
1259 	struct trace_seq *s = &iter->seq;
1260 
1261 	trace_assign_type(field, iter->ent);
1262 
1263 	trace_seq_printf(s, ": %lx : ", field->ip);
1264 	trace_seq_puts(s, field->str);
1265 
1266 	return trace_handle_return(s);
1267 }
1268 
1269 static struct trace_event_functions trace_bputs_funcs = {
1270 	.trace		= trace_bputs_print,
1271 	.raw		= trace_bputs_raw,
1272 };
1273 
1274 static struct trace_event trace_bputs_event = {
1275 	.type		= TRACE_BPUTS,
1276 	.funcs		= &trace_bputs_funcs,
1277 };
1278 
1279 /* TRACE_BPRINT */
1280 static enum print_line_t
1281 trace_bprint_print(struct trace_iterator *iter, int flags,
1282 		   struct trace_event *event)
1283 {
1284 	struct trace_entry *entry = iter->ent;
1285 	struct trace_seq *s = &iter->seq;
1286 	struct bprint_entry *field;
1287 
1288 	trace_assign_type(field, entry);
1289 
1290 	seq_print_ip_sym(s, field->ip, flags);
1291 	trace_seq_puts(s, ": ");
1292 	trace_seq_bprintf(s, field->fmt, field->buf);
1293 
1294 	return trace_handle_return(s);
1295 }
1296 
1297 
1298 static enum print_line_t
1299 trace_bprint_raw(struct trace_iterator *iter, int flags,
1300 		 struct trace_event *event)
1301 {
1302 	struct bprint_entry *field;
1303 	struct trace_seq *s = &iter->seq;
1304 
1305 	trace_assign_type(field, iter->ent);
1306 
1307 	trace_seq_printf(s, ": %lx : ", field->ip);
1308 	trace_seq_bprintf(s, field->fmt, field->buf);
1309 
1310 	return trace_handle_return(s);
1311 }
1312 
1313 static struct trace_event_functions trace_bprint_funcs = {
1314 	.trace		= trace_bprint_print,
1315 	.raw		= trace_bprint_raw,
1316 };
1317 
1318 static struct trace_event trace_bprint_event = {
1319 	.type		= TRACE_BPRINT,
1320 	.funcs		= &trace_bprint_funcs,
1321 };
1322 
1323 /* TRACE_PRINT */
1324 static enum print_line_t trace_print_print(struct trace_iterator *iter,
1325 					   int flags, struct trace_event *event)
1326 {
1327 	struct print_entry *field;
1328 	struct trace_seq *s = &iter->seq;
1329 
1330 	trace_assign_type(field, iter->ent);
1331 
1332 	seq_print_ip_sym(s, field->ip, flags);
1333 	trace_seq_printf(s, ": %s", field->buf);
1334 
1335 	return trace_handle_return(s);
1336 }
1337 
1338 static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags,
1339 					 struct trace_event *event)
1340 {
1341 	struct print_entry *field;
1342 
1343 	trace_assign_type(field, iter->ent);
1344 
1345 	trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf);
1346 
1347 	return trace_handle_return(&iter->seq);
1348 }
1349 
1350 static struct trace_event_functions trace_print_funcs = {
1351 	.trace		= trace_print_print,
1352 	.raw		= trace_print_raw,
1353 };
1354 
1355 static struct trace_event trace_print_event = {
1356 	.type	 	= TRACE_PRINT,
1357 	.funcs		= &trace_print_funcs,
1358 };
1359 
1360 static enum print_line_t trace_raw_data(struct trace_iterator *iter, int flags,
1361 					 struct trace_event *event)
1362 {
1363 	struct raw_data_entry *field;
1364 	int i;
1365 
1366 	trace_assign_type(field, iter->ent);
1367 
1368 	trace_seq_printf(&iter->seq, "# %x buf:", field->id);
1369 
1370 	for (i = 0; i < iter->ent_size - offsetof(struct raw_data_entry, buf); i++)
1371 		trace_seq_printf(&iter->seq, " %02x",
1372 				 (unsigned char)field->buf[i]);
1373 
1374 	trace_seq_putc(&iter->seq, '\n');
1375 
1376 	return trace_handle_return(&iter->seq);
1377 }
1378 
1379 static struct trace_event_functions trace_raw_data_funcs = {
1380 	.trace		= trace_raw_data,
1381 	.raw		= trace_raw_data,
1382 };
1383 
1384 static struct trace_event trace_raw_data_event = {
1385 	.type	 	= TRACE_RAW_DATA,
1386 	.funcs		= &trace_raw_data_funcs,
1387 };
1388 
1389 static enum print_line_t
1390 trace_func_repeats_raw(struct trace_iterator *iter, int flags,
1391 			 struct trace_event *event)
1392 {
1393 	struct func_repeats_entry *field;
1394 	struct trace_seq *s = &iter->seq;
1395 
1396 	trace_assign_type(field, iter->ent);
1397 
1398 	trace_seq_printf(s, "%lu %lu %u %llu\n",
1399 			 field->ip,
1400 			 field->parent_ip,
1401 			 field->count,
1402 			 FUNC_REPEATS_GET_DELTA_TS(field));
1403 
1404 	return trace_handle_return(s);
1405 }
1406 
1407 static enum print_line_t
1408 trace_func_repeats_print(struct trace_iterator *iter, int flags,
1409 			 struct trace_event *event)
1410 {
1411 	struct func_repeats_entry *field;
1412 	struct trace_seq *s = &iter->seq;
1413 
1414 	trace_assign_type(field, iter->ent);
1415 
1416 	print_fn_trace(s, field->ip, field->parent_ip, flags);
1417 	trace_seq_printf(s, " (repeats: %u, last_ts:", field->count);
1418 	trace_print_time(s, iter,
1419 			 iter->ts - FUNC_REPEATS_GET_DELTA_TS(field));
1420 	trace_seq_puts(s, ")\n");
1421 
1422 	return trace_handle_return(s);
1423 }
1424 
1425 static struct trace_event_functions trace_func_repeats_funcs = {
1426 	.trace		= trace_func_repeats_print,
1427 	.raw		= trace_func_repeats_raw,
1428 };
1429 
1430 static struct trace_event trace_func_repeats_event = {
1431 	.type	 	= TRACE_FUNC_REPEATS,
1432 	.funcs		= &trace_func_repeats_funcs,
1433 };
1434 
1435 static struct trace_event *events[] __initdata = {
1436 	&trace_fn_event,
1437 	&trace_ctx_event,
1438 	&trace_wake_event,
1439 	&trace_stack_event,
1440 	&trace_user_stack_event,
1441 	&trace_bputs_event,
1442 	&trace_bprint_event,
1443 	&trace_print_event,
1444 	&trace_hwlat_event,
1445 	&trace_raw_data_event,
1446 	&trace_func_repeats_event,
1447 	NULL
1448 };
1449 
1450 __init static int init_events(void)
1451 {
1452 	struct trace_event *event;
1453 	int i, ret;
1454 
1455 	for (i = 0; events[i]; i++) {
1456 		event = events[i];
1457 
1458 		ret = register_trace_event(event);
1459 		if (!ret) {
1460 			printk(KERN_WARNING "event %d failed to register\n",
1461 			       event->type);
1462 			WARN_ON_ONCE(1);
1463 		}
1464 	}
1465 
1466 	return 0;
1467 }
1468 early_initcall(init_events);
1469