xref: /openbmc/linux/kernel/trace/trace_output.c (revision 82e6fdd6)
1 /*
2  * trace_output.c
3  *
4  * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
5  *
6  */
7 #include <linux/module.h>
8 #include <linux/mutex.h>
9 #include <linux/ftrace.h>
10 #include <linux/sched/clock.h>
11 #include <linux/sched/mm.h>
12 
13 #include "trace_output.h"
14 
15 /* must be a power of 2 */
16 #define EVENT_HASHSIZE	128
17 
18 DECLARE_RWSEM(trace_event_sem);
19 
20 static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;
21 
22 static int next_event_type = __TRACE_LAST_TYPE + 1;
23 
24 enum print_line_t trace_print_bputs_msg_only(struct trace_iterator *iter)
25 {
26 	struct trace_seq *s = &iter->seq;
27 	struct trace_entry *entry = iter->ent;
28 	struct bputs_entry *field;
29 
30 	trace_assign_type(field, entry);
31 
32 	trace_seq_puts(s, field->str);
33 
34 	return trace_handle_return(s);
35 }
36 
37 enum print_line_t trace_print_bprintk_msg_only(struct trace_iterator *iter)
38 {
39 	struct trace_seq *s = &iter->seq;
40 	struct trace_entry *entry = iter->ent;
41 	struct bprint_entry *field;
42 
43 	trace_assign_type(field, entry);
44 
45 	trace_seq_bprintf(s, field->fmt, field->buf);
46 
47 	return trace_handle_return(s);
48 }
49 
50 enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter)
51 {
52 	struct trace_seq *s = &iter->seq;
53 	struct trace_entry *entry = iter->ent;
54 	struct print_entry *field;
55 
56 	trace_assign_type(field, entry);
57 
58 	trace_seq_puts(s, field->buf);
59 
60 	return trace_handle_return(s);
61 }
62 
63 const char *
64 trace_print_flags_seq(struct trace_seq *p, const char *delim,
65 		      unsigned long flags,
66 		      const struct trace_print_flags *flag_array)
67 {
68 	unsigned long mask;
69 	const char *str;
70 	const char *ret = trace_seq_buffer_ptr(p);
71 	int i, first = 1;
72 
73 	for (i = 0;  flag_array[i].name && flags; i++) {
74 
75 		mask = flag_array[i].mask;
76 		if ((flags & mask) != mask)
77 			continue;
78 
79 		str = flag_array[i].name;
80 		flags &= ~mask;
81 		if (!first && delim)
82 			trace_seq_puts(p, delim);
83 		else
84 			first = 0;
85 		trace_seq_puts(p, str);
86 	}
87 
88 	/* check for left over flags */
89 	if (flags) {
90 		if (!first && delim)
91 			trace_seq_puts(p, delim);
92 		trace_seq_printf(p, "0x%lx", flags);
93 	}
94 
95 	trace_seq_putc(p, 0);
96 
97 	return ret;
98 }
99 EXPORT_SYMBOL(trace_print_flags_seq);
100 
101 const char *
102 trace_print_symbols_seq(struct trace_seq *p, unsigned long val,
103 			const struct trace_print_flags *symbol_array)
104 {
105 	int i;
106 	const char *ret = trace_seq_buffer_ptr(p);
107 
108 	for (i = 0;  symbol_array[i].name; i++) {
109 
110 		if (val != symbol_array[i].mask)
111 			continue;
112 
113 		trace_seq_puts(p, symbol_array[i].name);
114 		break;
115 	}
116 
117 	if (ret == (const char *)(trace_seq_buffer_ptr(p)))
118 		trace_seq_printf(p, "0x%lx", val);
119 
120 	trace_seq_putc(p, 0);
121 
122 	return ret;
123 }
124 EXPORT_SYMBOL(trace_print_symbols_seq);
125 
126 #if BITS_PER_LONG == 32
127 const char *
128 trace_print_flags_seq_u64(struct trace_seq *p, const char *delim,
129 		      unsigned long long flags,
130 		      const struct trace_print_flags_u64 *flag_array)
131 {
132 	unsigned long long mask;
133 	const char *str;
134 	const char *ret = trace_seq_buffer_ptr(p);
135 	int i, first = 1;
136 
137 	for (i = 0;  flag_array[i].name && flags; i++) {
138 
139 		mask = flag_array[i].mask;
140 		if ((flags & mask) != mask)
141 			continue;
142 
143 		str = flag_array[i].name;
144 		flags &= ~mask;
145 		if (!first && delim)
146 			trace_seq_puts(p, delim);
147 		else
148 			first = 0;
149 		trace_seq_puts(p, str);
150 	}
151 
152 	/* check for left over flags */
153 	if (flags) {
154 		if (!first && delim)
155 			trace_seq_puts(p, delim);
156 		trace_seq_printf(p, "0x%llx", flags);
157 	}
158 
159 	trace_seq_putc(p, 0);
160 
161 	return ret;
162 }
163 EXPORT_SYMBOL(trace_print_flags_seq_u64);
164 
165 const char *
166 trace_print_symbols_seq_u64(struct trace_seq *p, unsigned long long val,
167 			 const struct trace_print_flags_u64 *symbol_array)
168 {
169 	int i;
170 	const char *ret = trace_seq_buffer_ptr(p);
171 
172 	for (i = 0;  symbol_array[i].name; i++) {
173 
174 		if (val != symbol_array[i].mask)
175 			continue;
176 
177 		trace_seq_puts(p, symbol_array[i].name);
178 		break;
179 	}
180 
181 	if (ret == (const char *)(trace_seq_buffer_ptr(p)))
182 		trace_seq_printf(p, "0x%llx", val);
183 
184 	trace_seq_putc(p, 0);
185 
186 	return ret;
187 }
188 EXPORT_SYMBOL(trace_print_symbols_seq_u64);
189 #endif
190 
191 const char *
192 trace_print_bitmask_seq(struct trace_seq *p, void *bitmask_ptr,
193 			unsigned int bitmask_size)
194 {
195 	const char *ret = trace_seq_buffer_ptr(p);
196 
197 	trace_seq_bitmask(p, bitmask_ptr, bitmask_size * 8);
198 	trace_seq_putc(p, 0);
199 
200 	return ret;
201 }
202 EXPORT_SYMBOL_GPL(trace_print_bitmask_seq);
203 
204 /**
205  * trace_print_hex_seq - print buffer as hex sequence
206  * @p: trace seq struct to write to
207  * @buf: The buffer to print
208  * @buf_len: Length of @buf in bytes
209  * @concatenate: Print @buf as single hex string or with spacing
210  *
211  * Prints the passed buffer as a hex sequence either as a whole,
212  * single hex string if @concatenate is true or with spacing after
213  * each byte in case @concatenate is false.
214  */
215 const char *
216 trace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len,
217 		    bool concatenate)
218 {
219 	int i;
220 	const char *ret = trace_seq_buffer_ptr(p);
221 
222 	for (i = 0; i < buf_len; i++)
223 		trace_seq_printf(p, "%s%2.2x", concatenate || i == 0 ? "" : " ",
224 				 buf[i]);
225 	trace_seq_putc(p, 0);
226 
227 	return ret;
228 }
229 EXPORT_SYMBOL(trace_print_hex_seq);
230 
231 const char *
232 trace_print_array_seq(struct trace_seq *p, const void *buf, int count,
233 		      size_t el_size)
234 {
235 	const char *ret = trace_seq_buffer_ptr(p);
236 	const char *prefix = "";
237 	void *ptr = (void *)buf;
238 	size_t buf_len = count * el_size;
239 
240 	trace_seq_putc(p, '{');
241 
242 	while (ptr < buf + buf_len) {
243 		switch (el_size) {
244 		case 1:
245 			trace_seq_printf(p, "%s0x%x", prefix,
246 					 *(u8 *)ptr);
247 			break;
248 		case 2:
249 			trace_seq_printf(p, "%s0x%x", prefix,
250 					 *(u16 *)ptr);
251 			break;
252 		case 4:
253 			trace_seq_printf(p, "%s0x%x", prefix,
254 					 *(u32 *)ptr);
255 			break;
256 		case 8:
257 			trace_seq_printf(p, "%s0x%llx", prefix,
258 					 *(u64 *)ptr);
259 			break;
260 		default:
261 			trace_seq_printf(p, "BAD SIZE:%zu 0x%x", el_size,
262 					 *(u8 *)ptr);
263 			el_size = 1;
264 		}
265 		prefix = ",";
266 		ptr += el_size;
267 	}
268 
269 	trace_seq_putc(p, '}');
270 	trace_seq_putc(p, 0);
271 
272 	return ret;
273 }
274 EXPORT_SYMBOL(trace_print_array_seq);
275 
276 int trace_raw_output_prep(struct trace_iterator *iter,
277 			  struct trace_event *trace_event)
278 {
279 	struct trace_event_call *event;
280 	struct trace_seq *s = &iter->seq;
281 	struct trace_seq *p = &iter->tmp_seq;
282 	struct trace_entry *entry;
283 
284 	event = container_of(trace_event, struct trace_event_call, event);
285 	entry = iter->ent;
286 
287 	if (entry->type != event->event.type) {
288 		WARN_ON_ONCE(1);
289 		return TRACE_TYPE_UNHANDLED;
290 	}
291 
292 	trace_seq_init(p);
293 	trace_seq_printf(s, "%s: ", trace_event_name(event));
294 
295 	return trace_handle_return(s);
296 }
297 EXPORT_SYMBOL(trace_raw_output_prep);
298 
299 static int trace_output_raw(struct trace_iterator *iter, char *name,
300 			    char *fmt, va_list ap)
301 {
302 	struct trace_seq *s = &iter->seq;
303 
304 	trace_seq_printf(s, "%s: ", name);
305 	trace_seq_vprintf(s, fmt, ap);
306 
307 	return trace_handle_return(s);
308 }
309 
310 int trace_output_call(struct trace_iterator *iter, char *name, char *fmt, ...)
311 {
312 	va_list ap;
313 	int ret;
314 
315 	va_start(ap, fmt);
316 	ret = trace_output_raw(iter, name, fmt, ap);
317 	va_end(ap);
318 
319 	return ret;
320 }
321 EXPORT_SYMBOL_GPL(trace_output_call);
322 
323 #ifdef CONFIG_KRETPROBES
324 static inline const char *kretprobed(const char *name)
325 {
326 	static const char tramp_name[] = "kretprobe_trampoline";
327 	int size = sizeof(tramp_name);
328 
329 	if (strncmp(tramp_name, name, size) == 0)
330 		return "[unknown/kretprobe'd]";
331 	return name;
332 }
333 #else
334 static inline const char *kretprobed(const char *name)
335 {
336 	return name;
337 }
338 #endif /* CONFIG_KRETPROBES */
339 
340 static void
341 seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
342 {
343 	char str[KSYM_SYMBOL_LEN];
344 #ifdef CONFIG_KALLSYMS
345 	const char *name;
346 
347 	kallsyms_lookup(address, NULL, NULL, NULL, str);
348 
349 	name = kretprobed(str);
350 
351 	if (name && strlen(name)) {
352 		trace_seq_printf(s, fmt, name);
353 		return;
354 	}
355 #endif
356 	snprintf(str, KSYM_SYMBOL_LEN, "0x%08lx", address);
357 	trace_seq_printf(s, fmt, str);
358 }
359 
360 static void
361 seq_print_sym_offset(struct trace_seq *s, const char *fmt,
362 		     unsigned long address)
363 {
364 	char str[KSYM_SYMBOL_LEN];
365 #ifdef CONFIG_KALLSYMS
366 	const char *name;
367 
368 	sprint_symbol(str, address);
369 	name = kretprobed(str);
370 
371 	if (name && strlen(name)) {
372 		trace_seq_printf(s, fmt, name);
373 		return;
374 	}
375 #endif
376 	snprintf(str, KSYM_SYMBOL_LEN, "0x%08lx", address);
377 	trace_seq_printf(s, fmt, str);
378 }
379 
380 #ifndef CONFIG_64BIT
381 # define IP_FMT "%08lx"
382 #else
383 # define IP_FMT "%016lx"
384 #endif
385 
386 static int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
387 			     unsigned long ip, unsigned long sym_flags)
388 {
389 	struct file *file = NULL;
390 	unsigned long vmstart = 0;
391 	int ret = 1;
392 
393 	if (s->full)
394 		return 0;
395 
396 	if (mm) {
397 		const struct vm_area_struct *vma;
398 
399 		down_read(&mm->mmap_sem);
400 		vma = find_vma(mm, ip);
401 		if (vma) {
402 			file = vma->vm_file;
403 			vmstart = vma->vm_start;
404 		}
405 		if (file) {
406 			ret = trace_seq_path(s, &file->f_path);
407 			if (ret)
408 				trace_seq_printf(s, "[+0x%lx]",
409 						 ip - vmstart);
410 		}
411 		up_read(&mm->mmap_sem);
412 	}
413 	if (ret && ((sym_flags & TRACE_ITER_SYM_ADDR) || !file))
414 		trace_seq_printf(s, " <" IP_FMT ">", ip);
415 	return !trace_seq_has_overflowed(s);
416 }
417 
418 int
419 seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
420 {
421 	if (!ip) {
422 		trace_seq_putc(s, '0');
423 		goto out;
424 	}
425 
426 	if (sym_flags & TRACE_ITER_SYM_OFFSET)
427 		seq_print_sym_offset(s, "%s", ip);
428 	else
429 		seq_print_sym_short(s, "%s", ip);
430 
431 	if (sym_flags & TRACE_ITER_SYM_ADDR)
432 		trace_seq_printf(s, " <" IP_FMT ">", ip);
433 
434  out:
435 	return !trace_seq_has_overflowed(s);
436 }
437 
438 /**
439  * trace_print_lat_fmt - print the irq, preempt and lockdep fields
440  * @s: trace seq struct to write to
441  * @entry: The trace entry field from the ring buffer
442  *
443  * Prints the generic fields of irqs off, in hard or softirq, preempt
444  * count.
445  */
446 int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
447 {
448 	char hardsoft_irq;
449 	char need_resched;
450 	char irqs_off;
451 	int hardirq;
452 	int softirq;
453 	int nmi;
454 
455 	nmi = entry->flags & TRACE_FLAG_NMI;
456 	hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
457 	softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
458 
459 	irqs_off =
460 		(entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
461 		(entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' :
462 		'.';
463 
464 	switch (entry->flags & (TRACE_FLAG_NEED_RESCHED |
465 				TRACE_FLAG_PREEMPT_RESCHED)) {
466 	case TRACE_FLAG_NEED_RESCHED | TRACE_FLAG_PREEMPT_RESCHED:
467 		need_resched = 'N';
468 		break;
469 	case TRACE_FLAG_NEED_RESCHED:
470 		need_resched = 'n';
471 		break;
472 	case TRACE_FLAG_PREEMPT_RESCHED:
473 		need_resched = 'p';
474 		break;
475 	default:
476 		need_resched = '.';
477 		break;
478 	}
479 
480 	hardsoft_irq =
481 		(nmi && hardirq)     ? 'Z' :
482 		nmi                  ? 'z' :
483 		(hardirq && softirq) ? 'H' :
484 		hardirq              ? 'h' :
485 		softirq              ? 's' :
486 		                       '.' ;
487 
488 	trace_seq_printf(s, "%c%c%c",
489 			 irqs_off, need_resched, hardsoft_irq);
490 
491 	if (entry->preempt_count)
492 		trace_seq_printf(s, "%x", entry->preempt_count);
493 	else
494 		trace_seq_putc(s, '.');
495 
496 	return !trace_seq_has_overflowed(s);
497 }
498 
499 static int
500 lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
501 {
502 	char comm[TASK_COMM_LEN];
503 
504 	trace_find_cmdline(entry->pid, comm);
505 
506 	trace_seq_printf(s, "%8.8s-%-5d %3d",
507 			 comm, entry->pid, cpu);
508 
509 	return trace_print_lat_fmt(s, entry);
510 }
511 
512 #undef MARK
513 #define MARK(v, s) {.val = v, .sym = s}
514 /* trace overhead mark */
515 static const struct trace_mark {
516 	unsigned long long	val; /* unit: nsec */
517 	char			sym;
518 } mark[] = {
519 	MARK(1000000000ULL	, '$'), /* 1 sec */
520 	MARK(100000000ULL	, '@'), /* 100 msec */
521 	MARK(10000000ULL	, '*'), /* 10 msec */
522 	MARK(1000000ULL		, '#'), /* 1000 usecs */
523 	MARK(100000ULL		, '!'), /* 100 usecs */
524 	MARK(10000ULL		, '+'), /* 10 usecs */
525 };
526 #undef MARK
527 
528 char trace_find_mark(unsigned long long d)
529 {
530 	int i;
531 	int size = ARRAY_SIZE(mark);
532 
533 	for (i = 0; i < size; i++) {
534 		if (d > mark[i].val)
535 			break;
536 	}
537 
538 	return (i == size) ? ' ' : mark[i].sym;
539 }
540 
541 static int
542 lat_print_timestamp(struct trace_iterator *iter, u64 next_ts)
543 {
544 	struct trace_array *tr = iter->tr;
545 	unsigned long verbose = tr->trace_flags & TRACE_ITER_VERBOSE;
546 	unsigned long in_ns = iter->iter_flags & TRACE_FILE_TIME_IN_NS;
547 	unsigned long long abs_ts = iter->ts - iter->trace_buffer->time_start;
548 	unsigned long long rel_ts = next_ts - iter->ts;
549 	struct trace_seq *s = &iter->seq;
550 
551 	if (in_ns) {
552 		abs_ts = ns2usecs(abs_ts);
553 		rel_ts = ns2usecs(rel_ts);
554 	}
555 
556 	if (verbose && in_ns) {
557 		unsigned long abs_usec = do_div(abs_ts, USEC_PER_MSEC);
558 		unsigned long abs_msec = (unsigned long)abs_ts;
559 		unsigned long rel_usec = do_div(rel_ts, USEC_PER_MSEC);
560 		unsigned long rel_msec = (unsigned long)rel_ts;
561 
562 		trace_seq_printf(
563 			s, "[%08llx] %ld.%03ldms (+%ld.%03ldms): ",
564 			ns2usecs(iter->ts),
565 			abs_msec, abs_usec,
566 			rel_msec, rel_usec);
567 
568 	} else if (verbose && !in_ns) {
569 		trace_seq_printf(
570 			s, "[%016llx] %lld (+%lld): ",
571 			iter->ts, abs_ts, rel_ts);
572 
573 	} else if (!verbose && in_ns) {
574 		trace_seq_printf(
575 			s, " %4lldus%c: ",
576 			abs_ts,
577 			trace_find_mark(rel_ts * NSEC_PER_USEC));
578 
579 	} else { /* !verbose && !in_ns */
580 		trace_seq_printf(s, " %4lld: ", abs_ts);
581 	}
582 
583 	return !trace_seq_has_overflowed(s);
584 }
585 
586 int trace_print_context(struct trace_iterator *iter)
587 {
588 	struct trace_array *tr = iter->tr;
589 	struct trace_seq *s = &iter->seq;
590 	struct trace_entry *entry = iter->ent;
591 	unsigned long long t;
592 	unsigned long secs, usec_rem;
593 	char comm[TASK_COMM_LEN];
594 
595 	trace_find_cmdline(entry->pid, comm);
596 
597 	trace_seq_printf(s, "%16s-%-5d [%03d] ",
598 			       comm, entry->pid, iter->cpu);
599 
600 	if (tr->trace_flags & TRACE_ITER_RECORD_TGID) {
601 		unsigned int tgid = trace_find_tgid(entry->pid);
602 
603 		if (!tgid)
604 			trace_seq_printf(s, "(-----) ");
605 		else
606 			trace_seq_printf(s, "(%5d) ", tgid);
607 	}
608 
609 	if (tr->trace_flags & TRACE_ITER_IRQ_INFO)
610 		trace_print_lat_fmt(s, entry);
611 
612 	if (iter->iter_flags & TRACE_FILE_TIME_IN_NS) {
613 		t = ns2usecs(iter->ts);
614 		usec_rem = do_div(t, USEC_PER_SEC);
615 		secs = (unsigned long)t;
616 		trace_seq_printf(s, " %5lu.%06lu: ", secs, usec_rem);
617 	} else
618 		trace_seq_printf(s, " %12llu: ", iter->ts);
619 
620 	return !trace_seq_has_overflowed(s);
621 }
622 
623 int trace_print_lat_context(struct trace_iterator *iter)
624 {
625 	struct trace_array *tr = iter->tr;
626 	/* trace_find_next_entry will reset ent_size */
627 	int ent_size = iter->ent_size;
628 	struct trace_seq *s = &iter->seq;
629 	u64 next_ts;
630 	struct trace_entry *entry = iter->ent,
631 			   *next_entry = trace_find_next_entry(iter, NULL,
632 							       &next_ts);
633 	unsigned long verbose = (tr->trace_flags & TRACE_ITER_VERBOSE);
634 
635 	/* Restore the original ent_size */
636 	iter->ent_size = ent_size;
637 
638 	if (!next_entry)
639 		next_ts = iter->ts;
640 
641 	if (verbose) {
642 		char comm[TASK_COMM_LEN];
643 
644 		trace_find_cmdline(entry->pid, comm);
645 
646 		trace_seq_printf(
647 			s, "%16s %5d %3d %d %08x %08lx ",
648 			comm, entry->pid, iter->cpu, entry->flags,
649 			entry->preempt_count, iter->idx);
650 	} else {
651 		lat_print_generic(s, entry, iter->cpu);
652 	}
653 
654 	lat_print_timestamp(iter, next_ts);
655 
656 	return !trace_seq_has_overflowed(s);
657 }
658 
659 /**
660  * ftrace_find_event - find a registered event
661  * @type: the type of event to look for
662  *
663  * Returns an event of type @type otherwise NULL
664  * Called with trace_event_read_lock() held.
665  */
666 struct trace_event *ftrace_find_event(int type)
667 {
668 	struct trace_event *event;
669 	unsigned key;
670 
671 	key = type & (EVENT_HASHSIZE - 1);
672 
673 	hlist_for_each_entry(event, &event_hash[key], node) {
674 		if (event->type == type)
675 			return event;
676 	}
677 
678 	return NULL;
679 }
680 
681 static LIST_HEAD(ftrace_event_list);
682 
683 static int trace_search_list(struct list_head **list)
684 {
685 	struct trace_event *e;
686 	int last = __TRACE_LAST_TYPE;
687 
688 	if (list_empty(&ftrace_event_list)) {
689 		*list = &ftrace_event_list;
690 		return last + 1;
691 	}
692 
693 	/*
694 	 * We used up all possible max events,
695 	 * lets see if somebody freed one.
696 	 */
697 	list_for_each_entry(e, &ftrace_event_list, list) {
698 		if (e->type != last + 1)
699 			break;
700 		last++;
701 	}
702 
703 	/* Did we used up all 65 thousand events??? */
704 	if ((last + 1) > TRACE_EVENT_TYPE_MAX)
705 		return 0;
706 
707 	*list = &e->list;
708 	return last + 1;
709 }
710 
711 void trace_event_read_lock(void)
712 {
713 	down_read(&trace_event_sem);
714 }
715 
716 void trace_event_read_unlock(void)
717 {
718 	up_read(&trace_event_sem);
719 }
720 
721 /**
722  * register_trace_event - register output for an event type
723  * @event: the event type to register
724  *
725  * Event types are stored in a hash and this hash is used to
726  * find a way to print an event. If the @event->type is set
727  * then it will use that type, otherwise it will assign a
728  * type to use.
729  *
730  * If you assign your own type, please make sure it is added
731  * to the trace_type enum in trace.h, to avoid collisions
732  * with the dynamic types.
733  *
734  * Returns the event type number or zero on error.
735  */
736 int register_trace_event(struct trace_event *event)
737 {
738 	unsigned key;
739 	int ret = 0;
740 
741 	down_write(&trace_event_sem);
742 
743 	if (WARN_ON(!event))
744 		goto out;
745 
746 	if (WARN_ON(!event->funcs))
747 		goto out;
748 
749 	INIT_LIST_HEAD(&event->list);
750 
751 	if (!event->type) {
752 		struct list_head *list = NULL;
753 
754 		if (next_event_type > TRACE_EVENT_TYPE_MAX) {
755 
756 			event->type = trace_search_list(&list);
757 			if (!event->type)
758 				goto out;
759 
760 		} else {
761 
762 			event->type = next_event_type++;
763 			list = &ftrace_event_list;
764 		}
765 
766 		if (WARN_ON(ftrace_find_event(event->type)))
767 			goto out;
768 
769 		list_add_tail(&event->list, list);
770 
771 	} else if (event->type > __TRACE_LAST_TYPE) {
772 		printk(KERN_WARNING "Need to add type to trace.h\n");
773 		WARN_ON(1);
774 		goto out;
775 	} else {
776 		/* Is this event already used */
777 		if (ftrace_find_event(event->type))
778 			goto out;
779 	}
780 
781 	if (event->funcs->trace == NULL)
782 		event->funcs->trace = trace_nop_print;
783 	if (event->funcs->raw == NULL)
784 		event->funcs->raw = trace_nop_print;
785 	if (event->funcs->hex == NULL)
786 		event->funcs->hex = trace_nop_print;
787 	if (event->funcs->binary == NULL)
788 		event->funcs->binary = trace_nop_print;
789 
790 	key = event->type & (EVENT_HASHSIZE - 1);
791 
792 	hlist_add_head(&event->node, &event_hash[key]);
793 
794 	ret = event->type;
795  out:
796 	up_write(&trace_event_sem);
797 
798 	return ret;
799 }
800 EXPORT_SYMBOL_GPL(register_trace_event);
801 
802 /*
803  * Used by module code with the trace_event_sem held for write.
804  */
805 int __unregister_trace_event(struct trace_event *event)
806 {
807 	hlist_del(&event->node);
808 	list_del(&event->list);
809 	return 0;
810 }
811 
812 /**
813  * unregister_trace_event - remove a no longer used event
814  * @event: the event to remove
815  */
816 int unregister_trace_event(struct trace_event *event)
817 {
818 	down_write(&trace_event_sem);
819 	__unregister_trace_event(event);
820 	up_write(&trace_event_sem);
821 
822 	return 0;
823 }
824 EXPORT_SYMBOL_GPL(unregister_trace_event);
825 
826 /*
827  * Standard events
828  */
829 
830 enum print_line_t trace_nop_print(struct trace_iterator *iter, int flags,
831 				  struct trace_event *event)
832 {
833 	trace_seq_printf(&iter->seq, "type: %d\n", iter->ent->type);
834 
835 	return trace_handle_return(&iter->seq);
836 }
837 
838 /* TRACE_FN */
839 static enum print_line_t trace_fn_trace(struct trace_iterator *iter, int flags,
840 					struct trace_event *event)
841 {
842 	struct ftrace_entry *field;
843 	struct trace_seq *s = &iter->seq;
844 
845 	trace_assign_type(field, iter->ent);
846 
847 	seq_print_ip_sym(s, field->ip, flags);
848 
849 	if ((flags & TRACE_ITER_PRINT_PARENT) && field->parent_ip) {
850 		trace_seq_puts(s, " <-");
851 		seq_print_ip_sym(s, field->parent_ip, flags);
852 	}
853 
854 	trace_seq_putc(s, '\n');
855 
856 	return trace_handle_return(s);
857 }
858 
859 static enum print_line_t trace_fn_raw(struct trace_iterator *iter, int flags,
860 				      struct trace_event *event)
861 {
862 	struct ftrace_entry *field;
863 
864 	trace_assign_type(field, iter->ent);
865 
866 	trace_seq_printf(&iter->seq, "%lx %lx\n",
867 			 field->ip,
868 			 field->parent_ip);
869 
870 	return trace_handle_return(&iter->seq);
871 }
872 
873 static enum print_line_t trace_fn_hex(struct trace_iterator *iter, int flags,
874 				      struct trace_event *event)
875 {
876 	struct ftrace_entry *field;
877 	struct trace_seq *s = &iter->seq;
878 
879 	trace_assign_type(field, iter->ent);
880 
881 	SEQ_PUT_HEX_FIELD(s, field->ip);
882 	SEQ_PUT_HEX_FIELD(s, field->parent_ip);
883 
884 	return trace_handle_return(s);
885 }
886 
887 static enum print_line_t trace_fn_bin(struct trace_iterator *iter, int flags,
888 				      struct trace_event *event)
889 {
890 	struct ftrace_entry *field;
891 	struct trace_seq *s = &iter->seq;
892 
893 	trace_assign_type(field, iter->ent);
894 
895 	SEQ_PUT_FIELD(s, field->ip);
896 	SEQ_PUT_FIELD(s, field->parent_ip);
897 
898 	return trace_handle_return(s);
899 }
900 
901 static struct trace_event_functions trace_fn_funcs = {
902 	.trace		= trace_fn_trace,
903 	.raw		= trace_fn_raw,
904 	.hex		= trace_fn_hex,
905 	.binary		= trace_fn_bin,
906 };
907 
908 static struct trace_event trace_fn_event = {
909 	.type		= TRACE_FN,
910 	.funcs		= &trace_fn_funcs,
911 };
912 
913 /* TRACE_CTX an TRACE_WAKE */
914 static enum print_line_t trace_ctxwake_print(struct trace_iterator *iter,
915 					     char *delim)
916 {
917 	struct ctx_switch_entry *field;
918 	char comm[TASK_COMM_LEN];
919 	int S, T;
920 
921 
922 	trace_assign_type(field, iter->ent);
923 
924 	T = task_index_to_char(field->next_state);
925 	S = task_index_to_char(field->prev_state);
926 	trace_find_cmdline(field->next_pid, comm);
927 	trace_seq_printf(&iter->seq,
928 			 " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
929 			 field->prev_pid,
930 			 field->prev_prio,
931 			 S, delim,
932 			 field->next_cpu,
933 			 field->next_pid,
934 			 field->next_prio,
935 			 T, comm);
936 
937 	return trace_handle_return(&iter->seq);
938 }
939 
940 static enum print_line_t trace_ctx_print(struct trace_iterator *iter, int flags,
941 					 struct trace_event *event)
942 {
943 	return trace_ctxwake_print(iter, "==>");
944 }
945 
946 static enum print_line_t trace_wake_print(struct trace_iterator *iter,
947 					  int flags, struct trace_event *event)
948 {
949 	return trace_ctxwake_print(iter, "  +");
950 }
951 
952 static int trace_ctxwake_raw(struct trace_iterator *iter, char S)
953 {
954 	struct ctx_switch_entry *field;
955 	int T;
956 
957 	trace_assign_type(field, iter->ent);
958 
959 	if (!S)
960 		S = task_index_to_char(field->prev_state);
961 	T = task_index_to_char(field->next_state);
962 	trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
963 			 field->prev_pid,
964 			 field->prev_prio,
965 			 S,
966 			 field->next_cpu,
967 			 field->next_pid,
968 			 field->next_prio,
969 			 T);
970 
971 	return trace_handle_return(&iter->seq);
972 }
973 
974 static enum print_line_t trace_ctx_raw(struct trace_iterator *iter, int flags,
975 				       struct trace_event *event)
976 {
977 	return trace_ctxwake_raw(iter, 0);
978 }
979 
980 static enum print_line_t trace_wake_raw(struct trace_iterator *iter, int flags,
981 					struct trace_event *event)
982 {
983 	return trace_ctxwake_raw(iter, '+');
984 }
985 
986 
987 static int trace_ctxwake_hex(struct trace_iterator *iter, char S)
988 {
989 	struct ctx_switch_entry *field;
990 	struct trace_seq *s = &iter->seq;
991 	int T;
992 
993 	trace_assign_type(field, iter->ent);
994 
995 	if (!S)
996 		S = task_index_to_char(field->prev_state);
997 	T = task_index_to_char(field->next_state);
998 
999 	SEQ_PUT_HEX_FIELD(s, field->prev_pid);
1000 	SEQ_PUT_HEX_FIELD(s, field->prev_prio);
1001 	SEQ_PUT_HEX_FIELD(s, S);
1002 	SEQ_PUT_HEX_FIELD(s, field->next_cpu);
1003 	SEQ_PUT_HEX_FIELD(s, field->next_pid);
1004 	SEQ_PUT_HEX_FIELD(s, field->next_prio);
1005 	SEQ_PUT_HEX_FIELD(s, T);
1006 
1007 	return trace_handle_return(s);
1008 }
1009 
1010 static enum print_line_t trace_ctx_hex(struct trace_iterator *iter, int flags,
1011 				       struct trace_event *event)
1012 {
1013 	return trace_ctxwake_hex(iter, 0);
1014 }
1015 
1016 static enum print_line_t trace_wake_hex(struct trace_iterator *iter, int flags,
1017 					struct trace_event *event)
1018 {
1019 	return trace_ctxwake_hex(iter, '+');
1020 }
1021 
1022 static enum print_line_t trace_ctxwake_bin(struct trace_iterator *iter,
1023 					   int flags, struct trace_event *event)
1024 {
1025 	struct ctx_switch_entry *field;
1026 	struct trace_seq *s = &iter->seq;
1027 
1028 	trace_assign_type(field, iter->ent);
1029 
1030 	SEQ_PUT_FIELD(s, field->prev_pid);
1031 	SEQ_PUT_FIELD(s, field->prev_prio);
1032 	SEQ_PUT_FIELD(s, field->prev_state);
1033 	SEQ_PUT_FIELD(s, field->next_cpu);
1034 	SEQ_PUT_FIELD(s, field->next_pid);
1035 	SEQ_PUT_FIELD(s, field->next_prio);
1036 	SEQ_PUT_FIELD(s, field->next_state);
1037 
1038 	return trace_handle_return(s);
1039 }
1040 
1041 static struct trace_event_functions trace_ctx_funcs = {
1042 	.trace		= trace_ctx_print,
1043 	.raw		= trace_ctx_raw,
1044 	.hex		= trace_ctx_hex,
1045 	.binary		= trace_ctxwake_bin,
1046 };
1047 
1048 static struct trace_event trace_ctx_event = {
1049 	.type		= TRACE_CTX,
1050 	.funcs		= &trace_ctx_funcs,
1051 };
1052 
1053 static struct trace_event_functions trace_wake_funcs = {
1054 	.trace		= trace_wake_print,
1055 	.raw		= trace_wake_raw,
1056 	.hex		= trace_wake_hex,
1057 	.binary		= trace_ctxwake_bin,
1058 };
1059 
1060 static struct trace_event trace_wake_event = {
1061 	.type		= TRACE_WAKE,
1062 	.funcs		= &trace_wake_funcs,
1063 };
1064 
1065 /* TRACE_STACK */
1066 
1067 static enum print_line_t trace_stack_print(struct trace_iterator *iter,
1068 					   int flags, struct trace_event *event)
1069 {
1070 	struct stack_entry *field;
1071 	struct trace_seq *s = &iter->seq;
1072 	unsigned long *p;
1073 	unsigned long *end;
1074 
1075 	trace_assign_type(field, iter->ent);
1076 	end = (unsigned long *)((long)iter->ent + iter->ent_size);
1077 
1078 	trace_seq_puts(s, "<stack trace>\n");
1079 
1080 	for (p = field->caller; p && *p != ULONG_MAX && p < end; p++) {
1081 
1082 		if (trace_seq_has_overflowed(s))
1083 			break;
1084 
1085 		trace_seq_puts(s, " => ");
1086 		seq_print_ip_sym(s, *p, flags);
1087 		trace_seq_putc(s, '\n');
1088 	}
1089 
1090 	return trace_handle_return(s);
1091 }
1092 
1093 static struct trace_event_functions trace_stack_funcs = {
1094 	.trace		= trace_stack_print,
1095 };
1096 
1097 static struct trace_event trace_stack_event = {
1098 	.type		= TRACE_STACK,
1099 	.funcs		= &trace_stack_funcs,
1100 };
1101 
1102 /* TRACE_USER_STACK */
1103 static enum print_line_t trace_user_stack_print(struct trace_iterator *iter,
1104 						int flags, struct trace_event *event)
1105 {
1106 	struct trace_array *tr = iter->tr;
1107 	struct userstack_entry *field;
1108 	struct trace_seq *s = &iter->seq;
1109 	struct mm_struct *mm = NULL;
1110 	unsigned int i;
1111 
1112 	trace_assign_type(field, iter->ent);
1113 
1114 	trace_seq_puts(s, "<user stack trace>\n");
1115 
1116 	if (tr->trace_flags & TRACE_ITER_SYM_USEROBJ) {
1117 		struct task_struct *task;
1118 		/*
1119 		 * we do the lookup on the thread group leader,
1120 		 * since individual threads might have already quit!
1121 		 */
1122 		rcu_read_lock();
1123 		task = find_task_by_vpid(field->tgid);
1124 		if (task)
1125 			mm = get_task_mm(task);
1126 		rcu_read_unlock();
1127 	}
1128 
1129 	for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
1130 		unsigned long ip = field->caller[i];
1131 
1132 		if (ip == ULONG_MAX || trace_seq_has_overflowed(s))
1133 			break;
1134 
1135 		trace_seq_puts(s, " => ");
1136 
1137 		if (!ip) {
1138 			trace_seq_puts(s, "??");
1139 			trace_seq_putc(s, '\n');
1140 			continue;
1141 		}
1142 
1143 		seq_print_user_ip(s, mm, ip, flags);
1144 		trace_seq_putc(s, '\n');
1145 	}
1146 
1147 	if (mm)
1148 		mmput(mm);
1149 
1150 	return trace_handle_return(s);
1151 }
1152 
1153 static struct trace_event_functions trace_user_stack_funcs = {
1154 	.trace		= trace_user_stack_print,
1155 };
1156 
1157 static struct trace_event trace_user_stack_event = {
1158 	.type		= TRACE_USER_STACK,
1159 	.funcs		= &trace_user_stack_funcs,
1160 };
1161 
1162 /* TRACE_HWLAT */
1163 static enum print_line_t
1164 trace_hwlat_print(struct trace_iterator *iter, int flags,
1165 		  struct trace_event *event)
1166 {
1167 	struct trace_entry *entry = iter->ent;
1168 	struct trace_seq *s = &iter->seq;
1169 	struct hwlat_entry *field;
1170 
1171 	trace_assign_type(field, entry);
1172 
1173 	trace_seq_printf(s, "#%-5u inner/outer(us): %4llu/%-5llu ts:%lld.%09ld",
1174 			 field->seqnum,
1175 			 field->duration,
1176 			 field->outer_duration,
1177 			 (long long)field->timestamp.tv_sec,
1178 			 field->timestamp.tv_nsec);
1179 
1180 	if (field->nmi_count) {
1181 		/*
1182 		 * The generic sched_clock() is not NMI safe, thus
1183 		 * we only record the count and not the time.
1184 		 */
1185 		if (!IS_ENABLED(CONFIG_GENERIC_SCHED_CLOCK))
1186 			trace_seq_printf(s, " nmi-total:%llu",
1187 					 field->nmi_total_ts);
1188 		trace_seq_printf(s, " nmi-count:%u",
1189 				 field->nmi_count);
1190 	}
1191 
1192 	trace_seq_putc(s, '\n');
1193 
1194 	return trace_handle_return(s);
1195 }
1196 
1197 
1198 static enum print_line_t
1199 trace_hwlat_raw(struct trace_iterator *iter, int flags,
1200 		struct trace_event *event)
1201 {
1202 	struct hwlat_entry *field;
1203 	struct trace_seq *s = &iter->seq;
1204 
1205 	trace_assign_type(field, iter->ent);
1206 
1207 	trace_seq_printf(s, "%llu %lld %lld %09ld %u\n",
1208 			 field->duration,
1209 			 field->outer_duration,
1210 			 (long long)field->timestamp.tv_sec,
1211 			 field->timestamp.tv_nsec,
1212 			 field->seqnum);
1213 
1214 	return trace_handle_return(s);
1215 }
1216 
1217 static struct trace_event_functions trace_hwlat_funcs = {
1218 	.trace		= trace_hwlat_print,
1219 	.raw		= trace_hwlat_raw,
1220 };
1221 
1222 static struct trace_event trace_hwlat_event = {
1223 	.type		= TRACE_HWLAT,
1224 	.funcs		= &trace_hwlat_funcs,
1225 };
1226 
1227 /* TRACE_BPUTS */
1228 static enum print_line_t
1229 trace_bputs_print(struct trace_iterator *iter, int flags,
1230 		   struct trace_event *event)
1231 {
1232 	struct trace_entry *entry = iter->ent;
1233 	struct trace_seq *s = &iter->seq;
1234 	struct bputs_entry *field;
1235 
1236 	trace_assign_type(field, entry);
1237 
1238 	seq_print_ip_sym(s, field->ip, flags);
1239 	trace_seq_puts(s, ": ");
1240 	trace_seq_puts(s, field->str);
1241 
1242 	return trace_handle_return(s);
1243 }
1244 
1245 
1246 static enum print_line_t
1247 trace_bputs_raw(struct trace_iterator *iter, int flags,
1248 		struct trace_event *event)
1249 {
1250 	struct bputs_entry *field;
1251 	struct trace_seq *s = &iter->seq;
1252 
1253 	trace_assign_type(field, iter->ent);
1254 
1255 	trace_seq_printf(s, ": %lx : ", field->ip);
1256 	trace_seq_puts(s, field->str);
1257 
1258 	return trace_handle_return(s);
1259 }
1260 
1261 static struct trace_event_functions trace_bputs_funcs = {
1262 	.trace		= trace_bputs_print,
1263 	.raw		= trace_bputs_raw,
1264 };
1265 
1266 static struct trace_event trace_bputs_event = {
1267 	.type		= TRACE_BPUTS,
1268 	.funcs		= &trace_bputs_funcs,
1269 };
1270 
1271 /* TRACE_BPRINT */
1272 static enum print_line_t
1273 trace_bprint_print(struct trace_iterator *iter, int flags,
1274 		   struct trace_event *event)
1275 {
1276 	struct trace_entry *entry = iter->ent;
1277 	struct trace_seq *s = &iter->seq;
1278 	struct bprint_entry *field;
1279 
1280 	trace_assign_type(field, entry);
1281 
1282 	seq_print_ip_sym(s, field->ip, flags);
1283 	trace_seq_puts(s, ": ");
1284 	trace_seq_bprintf(s, field->fmt, field->buf);
1285 
1286 	return trace_handle_return(s);
1287 }
1288 
1289 
1290 static enum print_line_t
1291 trace_bprint_raw(struct trace_iterator *iter, int flags,
1292 		 struct trace_event *event)
1293 {
1294 	struct bprint_entry *field;
1295 	struct trace_seq *s = &iter->seq;
1296 
1297 	trace_assign_type(field, iter->ent);
1298 
1299 	trace_seq_printf(s, ": %lx : ", field->ip);
1300 	trace_seq_bprintf(s, field->fmt, field->buf);
1301 
1302 	return trace_handle_return(s);
1303 }
1304 
1305 static struct trace_event_functions trace_bprint_funcs = {
1306 	.trace		= trace_bprint_print,
1307 	.raw		= trace_bprint_raw,
1308 };
1309 
1310 static struct trace_event trace_bprint_event = {
1311 	.type		= TRACE_BPRINT,
1312 	.funcs		= &trace_bprint_funcs,
1313 };
1314 
1315 /* TRACE_PRINT */
1316 static enum print_line_t trace_print_print(struct trace_iterator *iter,
1317 					   int flags, struct trace_event *event)
1318 {
1319 	struct print_entry *field;
1320 	struct trace_seq *s = &iter->seq;
1321 
1322 	trace_assign_type(field, iter->ent);
1323 
1324 	seq_print_ip_sym(s, field->ip, flags);
1325 	trace_seq_printf(s, ": %s", field->buf);
1326 
1327 	return trace_handle_return(s);
1328 }
1329 
1330 static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags,
1331 					 struct trace_event *event)
1332 {
1333 	struct print_entry *field;
1334 
1335 	trace_assign_type(field, iter->ent);
1336 
1337 	trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf);
1338 
1339 	return trace_handle_return(&iter->seq);
1340 }
1341 
1342 static struct trace_event_functions trace_print_funcs = {
1343 	.trace		= trace_print_print,
1344 	.raw		= trace_print_raw,
1345 };
1346 
1347 static struct trace_event trace_print_event = {
1348 	.type	 	= TRACE_PRINT,
1349 	.funcs		= &trace_print_funcs,
1350 };
1351 
1352 static enum print_line_t trace_raw_data(struct trace_iterator *iter, int flags,
1353 					 struct trace_event *event)
1354 {
1355 	struct raw_data_entry *field;
1356 	int i;
1357 
1358 	trace_assign_type(field, iter->ent);
1359 
1360 	trace_seq_printf(&iter->seq, "# %x buf:", field->id);
1361 
1362 	for (i = 0; i < iter->ent_size - offsetof(struct raw_data_entry, buf); i++)
1363 		trace_seq_printf(&iter->seq, " %02x",
1364 				 (unsigned char)field->buf[i]);
1365 
1366 	trace_seq_putc(&iter->seq, '\n');
1367 
1368 	return trace_handle_return(&iter->seq);
1369 }
1370 
1371 static struct trace_event_functions trace_raw_data_funcs = {
1372 	.trace		= trace_raw_data,
1373 	.raw		= trace_raw_data,
1374 };
1375 
1376 static struct trace_event trace_raw_data_event = {
1377 	.type	 	= TRACE_RAW_DATA,
1378 	.funcs		= &trace_raw_data_funcs,
1379 };
1380 
1381 
1382 static struct trace_event *events[] __initdata = {
1383 	&trace_fn_event,
1384 	&trace_ctx_event,
1385 	&trace_wake_event,
1386 	&trace_stack_event,
1387 	&trace_user_stack_event,
1388 	&trace_bputs_event,
1389 	&trace_bprint_event,
1390 	&trace_print_event,
1391 	&trace_hwlat_event,
1392 	&trace_raw_data_event,
1393 	NULL
1394 };
1395 
1396 __init static int init_events(void)
1397 {
1398 	struct trace_event *event;
1399 	int i, ret;
1400 
1401 	for (i = 0; events[i]; i++) {
1402 		event = events[i];
1403 
1404 		ret = register_trace_event(event);
1405 		if (!ret) {
1406 			printk(KERN_WARNING "event %d failed to register\n",
1407 			       event->type);
1408 			WARN_ON_ONCE(1);
1409 		}
1410 	}
1411 
1412 	return 0;
1413 }
1414 early_initcall(init_events);
1415