xref: /linux/kernel/trace/trace_output.c (revision ca853314e78b0a65c20b6a889a23c31f918d4aa2)
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 static int trace_output_raw(struct trace_iterator *iter, char *name,
316 			    char *fmt, va_list ap)
317 {
318 	struct trace_seq *s = &iter->seq;
319 
320 	trace_seq_printf(s, "%s: ", name);
321 	trace_seq_vprintf(s, fmt, ap);
322 
323 	return trace_handle_return(s);
324 }
325 
326 int trace_output_call(struct trace_iterator *iter, char *name, char *fmt, ...)
327 {
328 	va_list ap;
329 	int ret;
330 
331 	va_start(ap, fmt);
332 	ret = trace_output_raw(iter, name, fmt, ap);
333 	va_end(ap);
334 
335 	return ret;
336 }
337 EXPORT_SYMBOL_GPL(trace_output_call);
338 
339 #ifdef CONFIG_KRETPROBES
340 static inline const char *kretprobed(const char *name)
341 {
342 	static const char tramp_name[] = "kretprobe_trampoline";
343 	int size = sizeof(tramp_name);
344 
345 	if (strncmp(tramp_name, name, size) == 0)
346 		return "[unknown/kretprobe'd]";
347 	return name;
348 }
349 #else
350 static inline const char *kretprobed(const char *name)
351 {
352 	return name;
353 }
354 #endif /* CONFIG_KRETPROBES */
355 
356 void
357 trace_seq_print_sym(struct trace_seq *s, unsigned long address, bool offset)
358 {
359 #ifdef CONFIG_KALLSYMS
360 	char str[KSYM_SYMBOL_LEN];
361 	const char *name;
362 
363 	if (offset)
364 		sprint_symbol(str, address);
365 	else
366 		kallsyms_lookup(address, NULL, NULL, NULL, str);
367 	name = kretprobed(str);
368 
369 	if (name && strlen(name)) {
370 		trace_seq_puts(s, name);
371 		return;
372 	}
373 #endif
374 	trace_seq_printf(s, "0x%08lx", address);
375 }
376 
377 #ifndef CONFIG_64BIT
378 # define IP_FMT "%08lx"
379 #else
380 # define IP_FMT "%016lx"
381 #endif
382 
383 static int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
384 			     unsigned long ip, unsigned long sym_flags)
385 {
386 	struct file *file = NULL;
387 	unsigned long vmstart = 0;
388 	int ret = 1;
389 
390 	if (s->full)
391 		return 0;
392 
393 	if (mm) {
394 		const struct vm_area_struct *vma;
395 
396 		mmap_read_lock(mm);
397 		vma = find_vma(mm, ip);
398 		if (vma) {
399 			file = vma->vm_file;
400 			vmstart = vma->vm_start;
401 		}
402 		if (file) {
403 			ret = trace_seq_path(s, &file->f_path);
404 			if (ret)
405 				trace_seq_printf(s, "[+0x%lx]",
406 						 ip - vmstart);
407 		}
408 		mmap_read_unlock(mm);
409 	}
410 	if (ret && ((sym_flags & TRACE_ITER_SYM_ADDR) || !file))
411 		trace_seq_printf(s, " <" IP_FMT ">", ip);
412 	return !trace_seq_has_overflowed(s);
413 }
414 
415 int
416 seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
417 {
418 	if (!ip) {
419 		trace_seq_putc(s, '0');
420 		goto out;
421 	}
422 
423 	trace_seq_print_sym(s, ip, sym_flags & TRACE_ITER_SYM_OFFSET);
424 
425 	if (sym_flags & TRACE_ITER_SYM_ADDR)
426 		trace_seq_printf(s, " <" IP_FMT ">", ip);
427 
428  out:
429 	return !trace_seq_has_overflowed(s);
430 }
431 
432 /**
433  * trace_print_lat_fmt - print the irq, preempt and lockdep fields
434  * @s: trace seq struct to write to
435  * @entry: The trace entry field from the ring buffer
436  *
437  * Prints the generic fields of irqs off, in hard or softirq, preempt
438  * count.
439  */
440 int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
441 {
442 	char hardsoft_irq;
443 	char need_resched;
444 	char irqs_off;
445 	int hardirq;
446 	int softirq;
447 	int nmi;
448 
449 	nmi = entry->flags & TRACE_FLAG_NMI;
450 	hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
451 	softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
452 
453 	irqs_off =
454 		(entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
455 		(entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' :
456 		'.';
457 
458 	switch (entry->flags & (TRACE_FLAG_NEED_RESCHED |
459 				TRACE_FLAG_PREEMPT_RESCHED)) {
460 	case TRACE_FLAG_NEED_RESCHED | TRACE_FLAG_PREEMPT_RESCHED:
461 		need_resched = 'N';
462 		break;
463 	case TRACE_FLAG_NEED_RESCHED:
464 		need_resched = 'n';
465 		break;
466 	case TRACE_FLAG_PREEMPT_RESCHED:
467 		need_resched = 'p';
468 		break;
469 	default:
470 		need_resched = '.';
471 		break;
472 	}
473 
474 	hardsoft_irq =
475 		(nmi && hardirq)     ? 'Z' :
476 		nmi                  ? 'z' :
477 		(hardirq && softirq) ? 'H' :
478 		hardirq              ? 'h' :
479 		softirq              ? 's' :
480 		                       '.' ;
481 
482 	trace_seq_printf(s, "%c%c%c",
483 			 irqs_off, need_resched, hardsoft_irq);
484 
485 	if (entry->preempt_count)
486 		trace_seq_printf(s, "%x", entry->preempt_count);
487 	else
488 		trace_seq_putc(s, '.');
489 
490 	return !trace_seq_has_overflowed(s);
491 }
492 
493 static int
494 lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
495 {
496 	char comm[TASK_COMM_LEN];
497 
498 	trace_find_cmdline(entry->pid, comm);
499 
500 	trace_seq_printf(s, "%8.8s-%-7d %3d",
501 			 comm, entry->pid, cpu);
502 
503 	return trace_print_lat_fmt(s, entry);
504 }
505 
506 #undef MARK
507 #define MARK(v, s) {.val = v, .sym = s}
508 /* trace overhead mark */
509 static const struct trace_mark {
510 	unsigned long long	val; /* unit: nsec */
511 	char			sym;
512 } mark[] = {
513 	MARK(1000000000ULL	, '$'), /* 1 sec */
514 	MARK(100000000ULL	, '@'), /* 100 msec */
515 	MARK(10000000ULL	, '*'), /* 10 msec */
516 	MARK(1000000ULL		, '#'), /* 1000 usecs */
517 	MARK(100000ULL		, '!'), /* 100 usecs */
518 	MARK(10000ULL		, '+'), /* 10 usecs */
519 };
520 #undef MARK
521 
522 char trace_find_mark(unsigned long long d)
523 {
524 	int i;
525 	int size = ARRAY_SIZE(mark);
526 
527 	for (i = 0; i < size; i++) {
528 		if (d > mark[i].val)
529 			break;
530 	}
531 
532 	return (i == size) ? ' ' : mark[i].sym;
533 }
534 
535 static int
536 lat_print_timestamp(struct trace_iterator *iter, u64 next_ts)
537 {
538 	struct trace_array *tr = iter->tr;
539 	unsigned long verbose = tr->trace_flags & TRACE_ITER_VERBOSE;
540 	unsigned long in_ns = iter->iter_flags & TRACE_FILE_TIME_IN_NS;
541 	unsigned long long abs_ts = iter->ts - iter->array_buffer->time_start;
542 	unsigned long long rel_ts = next_ts - iter->ts;
543 	struct trace_seq *s = &iter->seq;
544 
545 	if (in_ns) {
546 		abs_ts = ns2usecs(abs_ts);
547 		rel_ts = ns2usecs(rel_ts);
548 	}
549 
550 	if (verbose && in_ns) {
551 		unsigned long abs_usec = do_div(abs_ts, USEC_PER_MSEC);
552 		unsigned long abs_msec = (unsigned long)abs_ts;
553 		unsigned long rel_usec = do_div(rel_ts, USEC_PER_MSEC);
554 		unsigned long rel_msec = (unsigned long)rel_ts;
555 
556 		trace_seq_printf(
557 			s, "[%08llx] %ld.%03ldms (+%ld.%03ldms): ",
558 			ns2usecs(iter->ts),
559 			abs_msec, abs_usec,
560 			rel_msec, rel_usec);
561 
562 	} else if (verbose && !in_ns) {
563 		trace_seq_printf(
564 			s, "[%016llx] %lld (+%lld): ",
565 			iter->ts, abs_ts, rel_ts);
566 
567 	} else if (!verbose && in_ns) {
568 		trace_seq_printf(
569 			s, " %4lldus%c: ",
570 			abs_ts,
571 			trace_find_mark(rel_ts * NSEC_PER_USEC));
572 
573 	} else { /* !verbose && !in_ns */
574 		trace_seq_printf(s, " %4lld: ", abs_ts);
575 	}
576 
577 	return !trace_seq_has_overflowed(s);
578 }
579 
580 int trace_print_context(struct trace_iterator *iter)
581 {
582 	struct trace_array *tr = iter->tr;
583 	struct trace_seq *s = &iter->seq;
584 	struct trace_entry *entry = iter->ent;
585 	unsigned long long t;
586 	unsigned long secs, usec_rem;
587 	char comm[TASK_COMM_LEN];
588 
589 	trace_find_cmdline(entry->pid, comm);
590 
591 	trace_seq_printf(s, "%16s-%-7d ", comm, entry->pid);
592 
593 	if (tr->trace_flags & TRACE_ITER_RECORD_TGID) {
594 		unsigned int tgid = trace_find_tgid(entry->pid);
595 
596 		if (!tgid)
597 			trace_seq_printf(s, "(-------) ");
598 		else
599 			trace_seq_printf(s, "(%7d) ", tgid);
600 	}
601 
602 	trace_seq_printf(s, "[%03d] ", iter->cpu);
603 
604 	if (tr->trace_flags & TRACE_ITER_IRQ_INFO)
605 		trace_print_lat_fmt(s, entry);
606 
607 	if (iter->iter_flags & TRACE_FILE_TIME_IN_NS) {
608 		t = ns2usecs(iter->ts);
609 		usec_rem = do_div(t, USEC_PER_SEC);
610 		secs = (unsigned long)t;
611 		trace_seq_printf(s, " %5lu.%06lu: ", secs, usec_rem);
612 	} else
613 		trace_seq_printf(s, " %12llu: ", iter->ts);
614 
615 	return !trace_seq_has_overflowed(s);
616 }
617 
618 int trace_print_lat_context(struct trace_iterator *iter)
619 {
620 	struct trace_entry *entry, *next_entry;
621 	struct trace_array *tr = iter->tr;
622 	struct trace_seq *s = &iter->seq;
623 	unsigned long verbose = (tr->trace_flags & TRACE_ITER_VERBOSE);
624 	u64 next_ts;
625 
626 	next_entry = trace_find_next_entry(iter, NULL, &next_ts);
627 	if (!next_entry)
628 		next_ts = iter->ts;
629 
630 	/* trace_find_next_entry() may change iter->ent */
631 	entry = iter->ent;
632 
633 	if (verbose) {
634 		char comm[TASK_COMM_LEN];
635 
636 		trace_find_cmdline(entry->pid, comm);
637 
638 		trace_seq_printf(
639 			s, "%16s %7d %3d %d %08x %08lx ",
640 			comm, entry->pid, iter->cpu, entry->flags,
641 			entry->preempt_count, iter->idx);
642 	} else {
643 		lat_print_generic(s, entry, iter->cpu);
644 	}
645 
646 	lat_print_timestamp(iter, next_ts);
647 
648 	return !trace_seq_has_overflowed(s);
649 }
650 
651 /**
652  * ftrace_find_event - find a registered event
653  * @type: the type of event to look for
654  *
655  * Returns an event of type @type otherwise NULL
656  * Called with trace_event_read_lock() held.
657  */
658 struct trace_event *ftrace_find_event(int type)
659 {
660 	struct trace_event *event;
661 	unsigned key;
662 
663 	key = type & (EVENT_HASHSIZE - 1);
664 
665 	hlist_for_each_entry(event, &event_hash[key], node) {
666 		if (event->type == type)
667 			return event;
668 	}
669 
670 	return NULL;
671 }
672 
673 static LIST_HEAD(ftrace_event_list);
674 
675 static int trace_search_list(struct list_head **list)
676 {
677 	struct trace_event *e;
678 	int next = __TRACE_LAST_TYPE;
679 
680 	if (list_empty(&ftrace_event_list)) {
681 		*list = &ftrace_event_list;
682 		return next;
683 	}
684 
685 	/*
686 	 * We used up all possible max events,
687 	 * lets see if somebody freed one.
688 	 */
689 	list_for_each_entry(e, &ftrace_event_list, list) {
690 		if (e->type != next)
691 			break;
692 		next++;
693 	}
694 
695 	/* Did we used up all 65 thousand events??? */
696 	if (next > TRACE_EVENT_TYPE_MAX)
697 		return 0;
698 
699 	*list = &e->list;
700 	return next;
701 }
702 
703 void trace_event_read_lock(void)
704 {
705 	down_read(&trace_event_sem);
706 }
707 
708 void trace_event_read_unlock(void)
709 {
710 	up_read(&trace_event_sem);
711 }
712 
713 /**
714  * register_trace_event - register output for an event type
715  * @event: the event type to register
716  *
717  * Event types are stored in a hash and this hash is used to
718  * find a way to print an event. If the @event->type is set
719  * then it will use that type, otherwise it will assign a
720  * type to use.
721  *
722  * If you assign your own type, please make sure it is added
723  * to the trace_type enum in trace.h, to avoid collisions
724  * with the dynamic types.
725  *
726  * Returns the event type number or zero on error.
727  */
728 int register_trace_event(struct trace_event *event)
729 {
730 	unsigned key;
731 	int ret = 0;
732 
733 	down_write(&trace_event_sem);
734 
735 	if (WARN_ON(!event))
736 		goto out;
737 
738 	if (WARN_ON(!event->funcs))
739 		goto out;
740 
741 	INIT_LIST_HEAD(&event->list);
742 
743 	if (!event->type) {
744 		struct list_head *list = NULL;
745 
746 		if (next_event_type > TRACE_EVENT_TYPE_MAX) {
747 
748 			event->type = trace_search_list(&list);
749 			if (!event->type)
750 				goto out;
751 
752 		} else {
753 
754 			event->type = next_event_type++;
755 			list = &ftrace_event_list;
756 		}
757 
758 		if (WARN_ON(ftrace_find_event(event->type)))
759 			goto out;
760 
761 		list_add_tail(&event->list, list);
762 
763 	} else if (event->type > __TRACE_LAST_TYPE) {
764 		printk(KERN_WARNING "Need to add type to trace.h\n");
765 		WARN_ON(1);
766 		goto out;
767 	} else {
768 		/* Is this event already used */
769 		if (ftrace_find_event(event->type))
770 			goto out;
771 	}
772 
773 	if (event->funcs->trace == NULL)
774 		event->funcs->trace = trace_nop_print;
775 	if (event->funcs->raw == NULL)
776 		event->funcs->raw = trace_nop_print;
777 	if (event->funcs->hex == NULL)
778 		event->funcs->hex = trace_nop_print;
779 	if (event->funcs->binary == NULL)
780 		event->funcs->binary = trace_nop_print;
781 
782 	key = event->type & (EVENT_HASHSIZE - 1);
783 
784 	hlist_add_head(&event->node, &event_hash[key]);
785 
786 	ret = event->type;
787  out:
788 	up_write(&trace_event_sem);
789 
790 	return ret;
791 }
792 EXPORT_SYMBOL_GPL(register_trace_event);
793 
794 /*
795  * Used by module code with the trace_event_sem held for write.
796  */
797 int __unregister_trace_event(struct trace_event *event)
798 {
799 	hlist_del(&event->node);
800 	list_del(&event->list);
801 	return 0;
802 }
803 
804 /**
805  * unregister_trace_event - remove a no longer used event
806  * @event: the event to remove
807  */
808 int unregister_trace_event(struct trace_event *event)
809 {
810 	down_write(&trace_event_sem);
811 	__unregister_trace_event(event);
812 	up_write(&trace_event_sem);
813 
814 	return 0;
815 }
816 EXPORT_SYMBOL_GPL(unregister_trace_event);
817 
818 /*
819  * Standard events
820  */
821 
822 enum print_line_t trace_nop_print(struct trace_iterator *iter, int flags,
823 				  struct trace_event *event)
824 {
825 	trace_seq_printf(&iter->seq, "type: %d\n", iter->ent->type);
826 
827 	return trace_handle_return(&iter->seq);
828 }
829 
830 /* TRACE_FN */
831 static enum print_line_t trace_fn_trace(struct trace_iterator *iter, int flags,
832 					struct trace_event *event)
833 {
834 	struct ftrace_entry *field;
835 	struct trace_seq *s = &iter->seq;
836 
837 	trace_assign_type(field, iter->ent);
838 
839 	seq_print_ip_sym(s, field->ip, flags);
840 
841 	if ((flags & TRACE_ITER_PRINT_PARENT) && field->parent_ip) {
842 		trace_seq_puts(s, " <-");
843 		seq_print_ip_sym(s, field->parent_ip, flags);
844 	}
845 
846 	trace_seq_putc(s, '\n');
847 
848 	return trace_handle_return(s);
849 }
850 
851 static enum print_line_t trace_fn_raw(struct trace_iterator *iter, int flags,
852 				      struct trace_event *event)
853 {
854 	struct ftrace_entry *field;
855 
856 	trace_assign_type(field, iter->ent);
857 
858 	trace_seq_printf(&iter->seq, "%lx %lx\n",
859 			 field->ip,
860 			 field->parent_ip);
861 
862 	return trace_handle_return(&iter->seq);
863 }
864 
865 static enum print_line_t trace_fn_hex(struct trace_iterator *iter, int flags,
866 				      struct trace_event *event)
867 {
868 	struct ftrace_entry *field;
869 	struct trace_seq *s = &iter->seq;
870 
871 	trace_assign_type(field, iter->ent);
872 
873 	SEQ_PUT_HEX_FIELD(s, field->ip);
874 	SEQ_PUT_HEX_FIELD(s, field->parent_ip);
875 
876 	return trace_handle_return(s);
877 }
878 
879 static enum print_line_t trace_fn_bin(struct trace_iterator *iter, int flags,
880 				      struct trace_event *event)
881 {
882 	struct ftrace_entry *field;
883 	struct trace_seq *s = &iter->seq;
884 
885 	trace_assign_type(field, iter->ent);
886 
887 	SEQ_PUT_FIELD(s, field->ip);
888 	SEQ_PUT_FIELD(s, field->parent_ip);
889 
890 	return trace_handle_return(s);
891 }
892 
893 static struct trace_event_functions trace_fn_funcs = {
894 	.trace		= trace_fn_trace,
895 	.raw		= trace_fn_raw,
896 	.hex		= trace_fn_hex,
897 	.binary		= trace_fn_bin,
898 };
899 
900 static struct trace_event trace_fn_event = {
901 	.type		= TRACE_FN,
902 	.funcs		= &trace_fn_funcs,
903 };
904 
905 /* TRACE_CTX an TRACE_WAKE */
906 static enum print_line_t trace_ctxwake_print(struct trace_iterator *iter,
907 					     char *delim)
908 {
909 	struct ctx_switch_entry *field;
910 	char comm[TASK_COMM_LEN];
911 	int S, T;
912 
913 
914 	trace_assign_type(field, iter->ent);
915 
916 	T = task_index_to_char(field->next_state);
917 	S = task_index_to_char(field->prev_state);
918 	trace_find_cmdline(field->next_pid, comm);
919 	trace_seq_printf(&iter->seq,
920 			 " %7d:%3d:%c %s [%03d] %7d:%3d:%c %s\n",
921 			 field->prev_pid,
922 			 field->prev_prio,
923 			 S, delim,
924 			 field->next_cpu,
925 			 field->next_pid,
926 			 field->next_prio,
927 			 T, comm);
928 
929 	return trace_handle_return(&iter->seq);
930 }
931 
932 static enum print_line_t trace_ctx_print(struct trace_iterator *iter, int flags,
933 					 struct trace_event *event)
934 {
935 	return trace_ctxwake_print(iter, "==>");
936 }
937 
938 static enum print_line_t trace_wake_print(struct trace_iterator *iter,
939 					  int flags, struct trace_event *event)
940 {
941 	return trace_ctxwake_print(iter, "  +");
942 }
943 
944 static int trace_ctxwake_raw(struct trace_iterator *iter, char S)
945 {
946 	struct ctx_switch_entry *field;
947 	int T;
948 
949 	trace_assign_type(field, iter->ent);
950 
951 	if (!S)
952 		S = task_index_to_char(field->prev_state);
953 	T = task_index_to_char(field->next_state);
954 	trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
955 			 field->prev_pid,
956 			 field->prev_prio,
957 			 S,
958 			 field->next_cpu,
959 			 field->next_pid,
960 			 field->next_prio,
961 			 T);
962 
963 	return trace_handle_return(&iter->seq);
964 }
965 
966 static enum print_line_t trace_ctx_raw(struct trace_iterator *iter, int flags,
967 				       struct trace_event *event)
968 {
969 	return trace_ctxwake_raw(iter, 0);
970 }
971 
972 static enum print_line_t trace_wake_raw(struct trace_iterator *iter, int flags,
973 					struct trace_event *event)
974 {
975 	return trace_ctxwake_raw(iter, '+');
976 }
977 
978 
979 static int trace_ctxwake_hex(struct trace_iterator *iter, char S)
980 {
981 	struct ctx_switch_entry *field;
982 	struct trace_seq *s = &iter->seq;
983 	int T;
984 
985 	trace_assign_type(field, iter->ent);
986 
987 	if (!S)
988 		S = task_index_to_char(field->prev_state);
989 	T = task_index_to_char(field->next_state);
990 
991 	SEQ_PUT_HEX_FIELD(s, field->prev_pid);
992 	SEQ_PUT_HEX_FIELD(s, field->prev_prio);
993 	SEQ_PUT_HEX_FIELD(s, S);
994 	SEQ_PUT_HEX_FIELD(s, field->next_cpu);
995 	SEQ_PUT_HEX_FIELD(s, field->next_pid);
996 	SEQ_PUT_HEX_FIELD(s, field->next_prio);
997 	SEQ_PUT_HEX_FIELD(s, T);
998 
999 	return trace_handle_return(s);
1000 }
1001 
1002 static enum print_line_t trace_ctx_hex(struct trace_iterator *iter, int flags,
1003 				       struct trace_event *event)
1004 {
1005 	return trace_ctxwake_hex(iter, 0);
1006 }
1007 
1008 static enum print_line_t trace_wake_hex(struct trace_iterator *iter, int flags,
1009 					struct trace_event *event)
1010 {
1011 	return trace_ctxwake_hex(iter, '+');
1012 }
1013 
1014 static enum print_line_t trace_ctxwake_bin(struct trace_iterator *iter,
1015 					   int flags, struct trace_event *event)
1016 {
1017 	struct ctx_switch_entry *field;
1018 	struct trace_seq *s = &iter->seq;
1019 
1020 	trace_assign_type(field, iter->ent);
1021 
1022 	SEQ_PUT_FIELD(s, field->prev_pid);
1023 	SEQ_PUT_FIELD(s, field->prev_prio);
1024 	SEQ_PUT_FIELD(s, field->prev_state);
1025 	SEQ_PUT_FIELD(s, field->next_cpu);
1026 	SEQ_PUT_FIELD(s, field->next_pid);
1027 	SEQ_PUT_FIELD(s, field->next_prio);
1028 	SEQ_PUT_FIELD(s, field->next_state);
1029 
1030 	return trace_handle_return(s);
1031 }
1032 
1033 static struct trace_event_functions trace_ctx_funcs = {
1034 	.trace		= trace_ctx_print,
1035 	.raw		= trace_ctx_raw,
1036 	.hex		= trace_ctx_hex,
1037 	.binary		= trace_ctxwake_bin,
1038 };
1039 
1040 static struct trace_event trace_ctx_event = {
1041 	.type		= TRACE_CTX,
1042 	.funcs		= &trace_ctx_funcs,
1043 };
1044 
1045 static struct trace_event_functions trace_wake_funcs = {
1046 	.trace		= trace_wake_print,
1047 	.raw		= trace_wake_raw,
1048 	.hex		= trace_wake_hex,
1049 	.binary		= trace_ctxwake_bin,
1050 };
1051 
1052 static struct trace_event trace_wake_event = {
1053 	.type		= TRACE_WAKE,
1054 	.funcs		= &trace_wake_funcs,
1055 };
1056 
1057 /* TRACE_STACK */
1058 
1059 static enum print_line_t trace_stack_print(struct trace_iterator *iter,
1060 					   int flags, struct trace_event *event)
1061 {
1062 	struct stack_entry *field;
1063 	struct trace_seq *s = &iter->seq;
1064 	unsigned long *p;
1065 	unsigned long *end;
1066 
1067 	trace_assign_type(field, iter->ent);
1068 	end = (unsigned long *)((long)iter->ent + iter->ent_size);
1069 
1070 	trace_seq_puts(s, "<stack trace>\n");
1071 
1072 	for (p = field->caller; p && p < end && *p != ULONG_MAX; p++) {
1073 
1074 		if (trace_seq_has_overflowed(s))
1075 			break;
1076 
1077 		trace_seq_puts(s, " => ");
1078 		seq_print_ip_sym(s, *p, flags);
1079 		trace_seq_putc(s, '\n');
1080 	}
1081 
1082 	return trace_handle_return(s);
1083 }
1084 
1085 static struct trace_event_functions trace_stack_funcs = {
1086 	.trace		= trace_stack_print,
1087 };
1088 
1089 static struct trace_event trace_stack_event = {
1090 	.type		= TRACE_STACK,
1091 	.funcs		= &trace_stack_funcs,
1092 };
1093 
1094 /* TRACE_USER_STACK */
1095 static enum print_line_t trace_user_stack_print(struct trace_iterator *iter,
1096 						int flags, struct trace_event *event)
1097 {
1098 	struct trace_array *tr = iter->tr;
1099 	struct userstack_entry *field;
1100 	struct trace_seq *s = &iter->seq;
1101 	struct mm_struct *mm = NULL;
1102 	unsigned int i;
1103 
1104 	trace_assign_type(field, iter->ent);
1105 
1106 	trace_seq_puts(s, "<user stack trace>\n");
1107 
1108 	if (tr->trace_flags & TRACE_ITER_SYM_USEROBJ) {
1109 		struct task_struct *task;
1110 		/*
1111 		 * we do the lookup on the thread group leader,
1112 		 * since individual threads might have already quit!
1113 		 */
1114 		rcu_read_lock();
1115 		task = find_task_by_vpid(field->tgid);
1116 		if (task)
1117 			mm = get_task_mm(task);
1118 		rcu_read_unlock();
1119 	}
1120 
1121 	for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
1122 		unsigned long ip = field->caller[i];
1123 
1124 		if (!ip || trace_seq_has_overflowed(s))
1125 			break;
1126 
1127 		trace_seq_puts(s, " => ");
1128 		seq_print_user_ip(s, mm, ip, flags);
1129 		trace_seq_putc(s, '\n');
1130 	}
1131 
1132 	if (mm)
1133 		mmput(mm);
1134 
1135 	return trace_handle_return(s);
1136 }
1137 
1138 static struct trace_event_functions trace_user_stack_funcs = {
1139 	.trace		= trace_user_stack_print,
1140 };
1141 
1142 static struct trace_event trace_user_stack_event = {
1143 	.type		= TRACE_USER_STACK,
1144 	.funcs		= &trace_user_stack_funcs,
1145 };
1146 
1147 /* TRACE_HWLAT */
1148 static enum print_line_t
1149 trace_hwlat_print(struct trace_iterator *iter, int flags,
1150 		  struct trace_event *event)
1151 {
1152 	struct trace_entry *entry = iter->ent;
1153 	struct trace_seq *s = &iter->seq;
1154 	struct hwlat_entry *field;
1155 
1156 	trace_assign_type(field, entry);
1157 
1158 	trace_seq_printf(s, "#%-5u inner/outer(us): %4llu/%-5llu ts:%lld.%09ld count:%d",
1159 			 field->seqnum,
1160 			 field->duration,
1161 			 field->outer_duration,
1162 			 (long long)field->timestamp.tv_sec,
1163 			 field->timestamp.tv_nsec, field->count);
1164 
1165 	if (field->nmi_count) {
1166 		/*
1167 		 * The generic sched_clock() is not NMI safe, thus
1168 		 * we only record the count and not the time.
1169 		 */
1170 		if (!IS_ENABLED(CONFIG_GENERIC_SCHED_CLOCK))
1171 			trace_seq_printf(s, " nmi-total:%llu",
1172 					 field->nmi_total_ts);
1173 		trace_seq_printf(s, " nmi-count:%u",
1174 				 field->nmi_count);
1175 	}
1176 
1177 	trace_seq_putc(s, '\n');
1178 
1179 	return trace_handle_return(s);
1180 }
1181 
1182 
1183 static enum print_line_t
1184 trace_hwlat_raw(struct trace_iterator *iter, int flags,
1185 		struct trace_event *event)
1186 {
1187 	struct hwlat_entry *field;
1188 	struct trace_seq *s = &iter->seq;
1189 
1190 	trace_assign_type(field, iter->ent);
1191 
1192 	trace_seq_printf(s, "%llu %lld %lld %09ld %u\n",
1193 			 field->duration,
1194 			 field->outer_duration,
1195 			 (long long)field->timestamp.tv_sec,
1196 			 field->timestamp.tv_nsec,
1197 			 field->seqnum);
1198 
1199 	return trace_handle_return(s);
1200 }
1201 
1202 static struct trace_event_functions trace_hwlat_funcs = {
1203 	.trace		= trace_hwlat_print,
1204 	.raw		= trace_hwlat_raw,
1205 };
1206 
1207 static struct trace_event trace_hwlat_event = {
1208 	.type		= TRACE_HWLAT,
1209 	.funcs		= &trace_hwlat_funcs,
1210 };
1211 
1212 /* TRACE_BPUTS */
1213 static enum print_line_t
1214 trace_bputs_print(struct trace_iterator *iter, int flags,
1215 		   struct trace_event *event)
1216 {
1217 	struct trace_entry *entry = iter->ent;
1218 	struct trace_seq *s = &iter->seq;
1219 	struct bputs_entry *field;
1220 
1221 	trace_assign_type(field, entry);
1222 
1223 	seq_print_ip_sym(s, field->ip, flags);
1224 	trace_seq_puts(s, ": ");
1225 	trace_seq_puts(s, field->str);
1226 
1227 	return trace_handle_return(s);
1228 }
1229 
1230 
1231 static enum print_line_t
1232 trace_bputs_raw(struct trace_iterator *iter, int flags,
1233 		struct trace_event *event)
1234 {
1235 	struct bputs_entry *field;
1236 	struct trace_seq *s = &iter->seq;
1237 
1238 	trace_assign_type(field, iter->ent);
1239 
1240 	trace_seq_printf(s, ": %lx : ", field->ip);
1241 	trace_seq_puts(s, field->str);
1242 
1243 	return trace_handle_return(s);
1244 }
1245 
1246 static struct trace_event_functions trace_bputs_funcs = {
1247 	.trace		= trace_bputs_print,
1248 	.raw		= trace_bputs_raw,
1249 };
1250 
1251 static struct trace_event trace_bputs_event = {
1252 	.type		= TRACE_BPUTS,
1253 	.funcs		= &trace_bputs_funcs,
1254 };
1255 
1256 /* TRACE_BPRINT */
1257 static enum print_line_t
1258 trace_bprint_print(struct trace_iterator *iter, int flags,
1259 		   struct trace_event *event)
1260 {
1261 	struct trace_entry *entry = iter->ent;
1262 	struct trace_seq *s = &iter->seq;
1263 	struct bprint_entry *field;
1264 
1265 	trace_assign_type(field, entry);
1266 
1267 	seq_print_ip_sym(s, field->ip, flags);
1268 	trace_seq_puts(s, ": ");
1269 	trace_seq_bprintf(s, field->fmt, field->buf);
1270 
1271 	return trace_handle_return(s);
1272 }
1273 
1274 
1275 static enum print_line_t
1276 trace_bprint_raw(struct trace_iterator *iter, int flags,
1277 		 struct trace_event *event)
1278 {
1279 	struct bprint_entry *field;
1280 	struct trace_seq *s = &iter->seq;
1281 
1282 	trace_assign_type(field, iter->ent);
1283 
1284 	trace_seq_printf(s, ": %lx : ", field->ip);
1285 	trace_seq_bprintf(s, field->fmt, field->buf);
1286 
1287 	return trace_handle_return(s);
1288 }
1289 
1290 static struct trace_event_functions trace_bprint_funcs = {
1291 	.trace		= trace_bprint_print,
1292 	.raw		= trace_bprint_raw,
1293 };
1294 
1295 static struct trace_event trace_bprint_event = {
1296 	.type		= TRACE_BPRINT,
1297 	.funcs		= &trace_bprint_funcs,
1298 };
1299 
1300 /* TRACE_PRINT */
1301 static enum print_line_t trace_print_print(struct trace_iterator *iter,
1302 					   int flags, struct trace_event *event)
1303 {
1304 	struct print_entry *field;
1305 	struct trace_seq *s = &iter->seq;
1306 
1307 	trace_assign_type(field, iter->ent);
1308 
1309 	seq_print_ip_sym(s, field->ip, flags);
1310 	trace_seq_printf(s, ": %s", field->buf);
1311 
1312 	return trace_handle_return(s);
1313 }
1314 
1315 static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags,
1316 					 struct trace_event *event)
1317 {
1318 	struct print_entry *field;
1319 
1320 	trace_assign_type(field, iter->ent);
1321 
1322 	trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf);
1323 
1324 	return trace_handle_return(&iter->seq);
1325 }
1326 
1327 static struct trace_event_functions trace_print_funcs = {
1328 	.trace		= trace_print_print,
1329 	.raw		= trace_print_raw,
1330 };
1331 
1332 static struct trace_event trace_print_event = {
1333 	.type	 	= TRACE_PRINT,
1334 	.funcs		= &trace_print_funcs,
1335 };
1336 
1337 static enum print_line_t trace_raw_data(struct trace_iterator *iter, int flags,
1338 					 struct trace_event *event)
1339 {
1340 	struct raw_data_entry *field;
1341 	int i;
1342 
1343 	trace_assign_type(field, iter->ent);
1344 
1345 	trace_seq_printf(&iter->seq, "# %x buf:", field->id);
1346 
1347 	for (i = 0; i < iter->ent_size - offsetof(struct raw_data_entry, buf); i++)
1348 		trace_seq_printf(&iter->seq, " %02x",
1349 				 (unsigned char)field->buf[i]);
1350 
1351 	trace_seq_putc(&iter->seq, '\n');
1352 
1353 	return trace_handle_return(&iter->seq);
1354 }
1355 
1356 static struct trace_event_functions trace_raw_data_funcs = {
1357 	.trace		= trace_raw_data,
1358 	.raw		= trace_raw_data,
1359 };
1360 
1361 static struct trace_event trace_raw_data_event = {
1362 	.type	 	= TRACE_RAW_DATA,
1363 	.funcs		= &trace_raw_data_funcs,
1364 };
1365 
1366 
1367 static struct trace_event *events[] __initdata = {
1368 	&trace_fn_event,
1369 	&trace_ctx_event,
1370 	&trace_wake_event,
1371 	&trace_stack_event,
1372 	&trace_user_stack_event,
1373 	&trace_bputs_event,
1374 	&trace_bprint_event,
1375 	&trace_print_event,
1376 	&trace_hwlat_event,
1377 	&trace_raw_data_event,
1378 	NULL
1379 };
1380 
1381 __init static int init_events(void)
1382 {
1383 	struct trace_event *event;
1384 	int i, ret;
1385 
1386 	for (i = 0; events[i]; i++) {
1387 		event = events[i];
1388 
1389 		ret = register_trace_event(event);
1390 		if (!ret) {
1391 			printk(KERN_WARNING "event %d failed to register\n",
1392 			       event->type);
1393 			WARN_ON_ONCE(1);
1394 		}
1395 	}
1396 
1397 	return 0;
1398 }
1399 early_initcall(init_events);
1400