xref: /openbmc/linux/kernel/trace/trace_output.c (revision 6c33a6f4)
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 + 1;
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 static void
357 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 		down_read(&mm->mmap_sem);
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 		up_read(&mm->mmap_sem);
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 	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-%-5d %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-%-5d ", 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, "(%5d) ", 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_array *tr = iter->tr;
621 	/* trace_find_next_entry will reset ent_size */
622 	int ent_size = iter->ent_size;
623 	struct trace_seq *s = &iter->seq;
624 	u64 next_ts;
625 	struct trace_entry *entry = iter->ent,
626 			   *next_entry = trace_find_next_entry(iter, NULL,
627 							       &next_ts);
628 	unsigned long verbose = (tr->trace_flags & TRACE_ITER_VERBOSE);
629 
630 	/* Restore the original ent_size */
631 	iter->ent_size = ent_size;
632 
633 	if (!next_entry)
634 		next_ts = iter->ts;
635 
636 	if (verbose) {
637 		char comm[TASK_COMM_LEN];
638 
639 		trace_find_cmdline(entry->pid, comm);
640 
641 		trace_seq_printf(
642 			s, "%16s %5d %3d %d %08x %08lx ",
643 			comm, entry->pid, iter->cpu, entry->flags,
644 			entry->preempt_count, iter->idx);
645 	} else {
646 		lat_print_generic(s, entry, iter->cpu);
647 	}
648 
649 	lat_print_timestamp(iter, next_ts);
650 
651 	return !trace_seq_has_overflowed(s);
652 }
653 
654 /**
655  * ftrace_find_event - find a registered event
656  * @type: the type of event to look for
657  *
658  * Returns an event of type @type otherwise NULL
659  * Called with trace_event_read_lock() held.
660  */
661 struct trace_event *ftrace_find_event(int type)
662 {
663 	struct trace_event *event;
664 	unsigned key;
665 
666 	key = type & (EVENT_HASHSIZE - 1);
667 
668 	hlist_for_each_entry(event, &event_hash[key], node) {
669 		if (event->type == type)
670 			return event;
671 	}
672 
673 	return NULL;
674 }
675 
676 static LIST_HEAD(ftrace_event_list);
677 
678 static int trace_search_list(struct list_head **list)
679 {
680 	struct trace_event *e;
681 	int last = __TRACE_LAST_TYPE;
682 
683 	if (list_empty(&ftrace_event_list)) {
684 		*list = &ftrace_event_list;
685 		return last + 1;
686 	}
687 
688 	/*
689 	 * We used up all possible max events,
690 	 * lets see if somebody freed one.
691 	 */
692 	list_for_each_entry(e, &ftrace_event_list, list) {
693 		if (e->type != last + 1)
694 			break;
695 		last++;
696 	}
697 
698 	/* Did we used up all 65 thousand events??? */
699 	if ((last + 1) > TRACE_EVENT_TYPE_MAX)
700 		return 0;
701 
702 	*list = &e->list;
703 	return last + 1;
704 }
705 
706 void trace_event_read_lock(void)
707 {
708 	down_read(&trace_event_sem);
709 }
710 
711 void trace_event_read_unlock(void)
712 {
713 	up_read(&trace_event_sem);
714 }
715 
716 /**
717  * register_trace_event - register output for an event type
718  * @event: the event type to register
719  *
720  * Event types are stored in a hash and this hash is used to
721  * find a way to print an event. If the @event->type is set
722  * then it will use that type, otherwise it will assign a
723  * type to use.
724  *
725  * If you assign your own type, please make sure it is added
726  * to the trace_type enum in trace.h, to avoid collisions
727  * with the dynamic types.
728  *
729  * Returns the event type number or zero on error.
730  */
731 int register_trace_event(struct trace_event *event)
732 {
733 	unsigned key;
734 	int ret = 0;
735 
736 	down_write(&trace_event_sem);
737 
738 	if (WARN_ON(!event))
739 		goto out;
740 
741 	if (WARN_ON(!event->funcs))
742 		goto out;
743 
744 	INIT_LIST_HEAD(&event->list);
745 
746 	if (!event->type) {
747 		struct list_head *list = NULL;
748 
749 		if (next_event_type > TRACE_EVENT_TYPE_MAX) {
750 
751 			event->type = trace_search_list(&list);
752 			if (!event->type)
753 				goto out;
754 
755 		} else {
756 
757 			event->type = next_event_type++;
758 			list = &ftrace_event_list;
759 		}
760 
761 		if (WARN_ON(ftrace_find_event(event->type)))
762 			goto out;
763 
764 		list_add_tail(&event->list, list);
765 
766 	} else if (event->type > __TRACE_LAST_TYPE) {
767 		printk(KERN_WARNING "Need to add type to trace.h\n");
768 		WARN_ON(1);
769 		goto out;
770 	} else {
771 		/* Is this event already used */
772 		if (ftrace_find_event(event->type))
773 			goto out;
774 	}
775 
776 	if (event->funcs->trace == NULL)
777 		event->funcs->trace = trace_nop_print;
778 	if (event->funcs->raw == NULL)
779 		event->funcs->raw = trace_nop_print;
780 	if (event->funcs->hex == NULL)
781 		event->funcs->hex = trace_nop_print;
782 	if (event->funcs->binary == NULL)
783 		event->funcs->binary = trace_nop_print;
784 
785 	key = event->type & (EVENT_HASHSIZE - 1);
786 
787 	hlist_add_head(&event->node, &event_hash[key]);
788 
789 	ret = event->type;
790  out:
791 	up_write(&trace_event_sem);
792 
793 	return ret;
794 }
795 EXPORT_SYMBOL_GPL(register_trace_event);
796 
797 /*
798  * Used by module code with the trace_event_sem held for write.
799  */
800 int __unregister_trace_event(struct trace_event *event)
801 {
802 	hlist_del(&event->node);
803 	list_del(&event->list);
804 	return 0;
805 }
806 
807 /**
808  * unregister_trace_event - remove a no longer used event
809  * @event: the event to remove
810  */
811 int unregister_trace_event(struct trace_event *event)
812 {
813 	down_write(&trace_event_sem);
814 	__unregister_trace_event(event);
815 	up_write(&trace_event_sem);
816 
817 	return 0;
818 }
819 EXPORT_SYMBOL_GPL(unregister_trace_event);
820 
821 /*
822  * Standard events
823  */
824 
825 enum print_line_t trace_nop_print(struct trace_iterator *iter, int flags,
826 				  struct trace_event *event)
827 {
828 	trace_seq_printf(&iter->seq, "type: %d\n", iter->ent->type);
829 
830 	return trace_handle_return(&iter->seq);
831 }
832 
833 /* TRACE_FN */
834 static enum print_line_t trace_fn_trace(struct trace_iterator *iter, int flags,
835 					struct trace_event *event)
836 {
837 	struct ftrace_entry *field;
838 	struct trace_seq *s = &iter->seq;
839 
840 	trace_assign_type(field, iter->ent);
841 
842 	seq_print_ip_sym(s, field->ip, flags);
843 
844 	if ((flags & TRACE_ITER_PRINT_PARENT) && field->parent_ip) {
845 		trace_seq_puts(s, " <-");
846 		seq_print_ip_sym(s, field->parent_ip, flags);
847 	}
848 
849 	trace_seq_putc(s, '\n');
850 
851 	return trace_handle_return(s);
852 }
853 
854 static enum print_line_t trace_fn_raw(struct trace_iterator *iter, int flags,
855 				      struct trace_event *event)
856 {
857 	struct ftrace_entry *field;
858 
859 	trace_assign_type(field, iter->ent);
860 
861 	trace_seq_printf(&iter->seq, "%lx %lx\n",
862 			 field->ip,
863 			 field->parent_ip);
864 
865 	return trace_handle_return(&iter->seq);
866 }
867 
868 static enum print_line_t trace_fn_hex(struct trace_iterator *iter, int flags,
869 				      struct trace_event *event)
870 {
871 	struct ftrace_entry *field;
872 	struct trace_seq *s = &iter->seq;
873 
874 	trace_assign_type(field, iter->ent);
875 
876 	SEQ_PUT_HEX_FIELD(s, field->ip);
877 	SEQ_PUT_HEX_FIELD(s, field->parent_ip);
878 
879 	return trace_handle_return(s);
880 }
881 
882 static enum print_line_t trace_fn_bin(struct trace_iterator *iter, int flags,
883 				      struct trace_event *event)
884 {
885 	struct ftrace_entry *field;
886 	struct trace_seq *s = &iter->seq;
887 
888 	trace_assign_type(field, iter->ent);
889 
890 	SEQ_PUT_FIELD(s, field->ip);
891 	SEQ_PUT_FIELD(s, field->parent_ip);
892 
893 	return trace_handle_return(s);
894 }
895 
896 static struct trace_event_functions trace_fn_funcs = {
897 	.trace		= trace_fn_trace,
898 	.raw		= trace_fn_raw,
899 	.hex		= trace_fn_hex,
900 	.binary		= trace_fn_bin,
901 };
902 
903 static struct trace_event trace_fn_event = {
904 	.type		= TRACE_FN,
905 	.funcs		= &trace_fn_funcs,
906 };
907 
908 /* TRACE_CTX an TRACE_WAKE */
909 static enum print_line_t trace_ctxwake_print(struct trace_iterator *iter,
910 					     char *delim)
911 {
912 	struct ctx_switch_entry *field;
913 	char comm[TASK_COMM_LEN];
914 	int S, T;
915 
916 
917 	trace_assign_type(field, iter->ent);
918 
919 	T = task_index_to_char(field->next_state);
920 	S = task_index_to_char(field->prev_state);
921 	trace_find_cmdline(field->next_pid, comm);
922 	trace_seq_printf(&iter->seq,
923 			 " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
924 			 field->prev_pid,
925 			 field->prev_prio,
926 			 S, delim,
927 			 field->next_cpu,
928 			 field->next_pid,
929 			 field->next_prio,
930 			 T, comm);
931 
932 	return trace_handle_return(&iter->seq);
933 }
934 
935 static enum print_line_t trace_ctx_print(struct trace_iterator *iter, int flags,
936 					 struct trace_event *event)
937 {
938 	return trace_ctxwake_print(iter, "==>");
939 }
940 
941 static enum print_line_t trace_wake_print(struct trace_iterator *iter,
942 					  int flags, struct trace_event *event)
943 {
944 	return trace_ctxwake_print(iter, "  +");
945 }
946 
947 static int trace_ctxwake_raw(struct trace_iterator *iter, char S)
948 {
949 	struct ctx_switch_entry *field;
950 	int T;
951 
952 	trace_assign_type(field, iter->ent);
953 
954 	if (!S)
955 		S = task_index_to_char(field->prev_state);
956 	T = task_index_to_char(field->next_state);
957 	trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
958 			 field->prev_pid,
959 			 field->prev_prio,
960 			 S,
961 			 field->next_cpu,
962 			 field->next_pid,
963 			 field->next_prio,
964 			 T);
965 
966 	return trace_handle_return(&iter->seq);
967 }
968 
969 static enum print_line_t trace_ctx_raw(struct trace_iterator *iter, int flags,
970 				       struct trace_event *event)
971 {
972 	return trace_ctxwake_raw(iter, 0);
973 }
974 
975 static enum print_line_t trace_wake_raw(struct trace_iterator *iter, int flags,
976 					struct trace_event *event)
977 {
978 	return trace_ctxwake_raw(iter, '+');
979 }
980 
981 
982 static int trace_ctxwake_hex(struct trace_iterator *iter, char S)
983 {
984 	struct ctx_switch_entry *field;
985 	struct trace_seq *s = &iter->seq;
986 	int T;
987 
988 	trace_assign_type(field, iter->ent);
989 
990 	if (!S)
991 		S = task_index_to_char(field->prev_state);
992 	T = task_index_to_char(field->next_state);
993 
994 	SEQ_PUT_HEX_FIELD(s, field->prev_pid);
995 	SEQ_PUT_HEX_FIELD(s, field->prev_prio);
996 	SEQ_PUT_HEX_FIELD(s, S);
997 	SEQ_PUT_HEX_FIELD(s, field->next_cpu);
998 	SEQ_PUT_HEX_FIELD(s, field->next_pid);
999 	SEQ_PUT_HEX_FIELD(s, field->next_prio);
1000 	SEQ_PUT_HEX_FIELD(s, T);
1001 
1002 	return trace_handle_return(s);
1003 }
1004 
1005 static enum print_line_t trace_ctx_hex(struct trace_iterator *iter, int flags,
1006 				       struct trace_event *event)
1007 {
1008 	return trace_ctxwake_hex(iter, 0);
1009 }
1010 
1011 static enum print_line_t trace_wake_hex(struct trace_iterator *iter, int flags,
1012 					struct trace_event *event)
1013 {
1014 	return trace_ctxwake_hex(iter, '+');
1015 }
1016 
1017 static enum print_line_t trace_ctxwake_bin(struct trace_iterator *iter,
1018 					   int flags, struct trace_event *event)
1019 {
1020 	struct ctx_switch_entry *field;
1021 	struct trace_seq *s = &iter->seq;
1022 
1023 	trace_assign_type(field, iter->ent);
1024 
1025 	SEQ_PUT_FIELD(s, field->prev_pid);
1026 	SEQ_PUT_FIELD(s, field->prev_prio);
1027 	SEQ_PUT_FIELD(s, field->prev_state);
1028 	SEQ_PUT_FIELD(s, field->next_cpu);
1029 	SEQ_PUT_FIELD(s, field->next_pid);
1030 	SEQ_PUT_FIELD(s, field->next_prio);
1031 	SEQ_PUT_FIELD(s, field->next_state);
1032 
1033 	return trace_handle_return(s);
1034 }
1035 
1036 static struct trace_event_functions trace_ctx_funcs = {
1037 	.trace		= trace_ctx_print,
1038 	.raw		= trace_ctx_raw,
1039 	.hex		= trace_ctx_hex,
1040 	.binary		= trace_ctxwake_bin,
1041 };
1042 
1043 static struct trace_event trace_ctx_event = {
1044 	.type		= TRACE_CTX,
1045 	.funcs		= &trace_ctx_funcs,
1046 };
1047 
1048 static struct trace_event_functions trace_wake_funcs = {
1049 	.trace		= trace_wake_print,
1050 	.raw		= trace_wake_raw,
1051 	.hex		= trace_wake_hex,
1052 	.binary		= trace_ctxwake_bin,
1053 };
1054 
1055 static struct trace_event trace_wake_event = {
1056 	.type		= TRACE_WAKE,
1057 	.funcs		= &trace_wake_funcs,
1058 };
1059 
1060 /* TRACE_STACK */
1061 
1062 static enum print_line_t trace_stack_print(struct trace_iterator *iter,
1063 					   int flags, struct trace_event *event)
1064 {
1065 	struct stack_entry *field;
1066 	struct trace_seq *s = &iter->seq;
1067 	unsigned long *p;
1068 	unsigned long *end;
1069 
1070 	trace_assign_type(field, iter->ent);
1071 	end = (unsigned long *)((long)iter->ent + iter->ent_size);
1072 
1073 	trace_seq_puts(s, "<stack trace>\n");
1074 
1075 	for (p = field->caller; p && p < end && *p != ULONG_MAX; p++) {
1076 
1077 		if (trace_seq_has_overflowed(s))
1078 			break;
1079 
1080 		trace_seq_puts(s, " => ");
1081 		seq_print_ip_sym(s, *p, flags);
1082 		trace_seq_putc(s, '\n');
1083 	}
1084 
1085 	return trace_handle_return(s);
1086 }
1087 
1088 static struct trace_event_functions trace_stack_funcs = {
1089 	.trace		= trace_stack_print,
1090 };
1091 
1092 static struct trace_event trace_stack_event = {
1093 	.type		= TRACE_STACK,
1094 	.funcs		= &trace_stack_funcs,
1095 };
1096 
1097 /* TRACE_USER_STACK */
1098 static enum print_line_t trace_user_stack_print(struct trace_iterator *iter,
1099 						int flags, struct trace_event *event)
1100 {
1101 	struct trace_array *tr = iter->tr;
1102 	struct userstack_entry *field;
1103 	struct trace_seq *s = &iter->seq;
1104 	struct mm_struct *mm = NULL;
1105 	unsigned int i;
1106 
1107 	trace_assign_type(field, iter->ent);
1108 
1109 	trace_seq_puts(s, "<user stack trace>\n");
1110 
1111 	if (tr->trace_flags & TRACE_ITER_SYM_USEROBJ) {
1112 		struct task_struct *task;
1113 		/*
1114 		 * we do the lookup on the thread group leader,
1115 		 * since individual threads might have already quit!
1116 		 */
1117 		rcu_read_lock();
1118 		task = find_task_by_vpid(field->tgid);
1119 		if (task)
1120 			mm = get_task_mm(task);
1121 		rcu_read_unlock();
1122 	}
1123 
1124 	for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
1125 		unsigned long ip = field->caller[i];
1126 
1127 		if (!ip || trace_seq_has_overflowed(s))
1128 			break;
1129 
1130 		trace_seq_puts(s, " => ");
1131 		seq_print_user_ip(s, mm, ip, flags);
1132 		trace_seq_putc(s, '\n');
1133 	}
1134 
1135 	if (mm)
1136 		mmput(mm);
1137 
1138 	return trace_handle_return(s);
1139 }
1140 
1141 static struct trace_event_functions trace_user_stack_funcs = {
1142 	.trace		= trace_user_stack_print,
1143 };
1144 
1145 static struct trace_event trace_user_stack_event = {
1146 	.type		= TRACE_USER_STACK,
1147 	.funcs		= &trace_user_stack_funcs,
1148 };
1149 
1150 /* TRACE_HWLAT */
1151 static enum print_line_t
1152 trace_hwlat_print(struct trace_iterator *iter, int flags,
1153 		  struct trace_event *event)
1154 {
1155 	struct trace_entry *entry = iter->ent;
1156 	struct trace_seq *s = &iter->seq;
1157 	struct hwlat_entry *field;
1158 
1159 	trace_assign_type(field, entry);
1160 
1161 	trace_seq_printf(s, "#%-5u inner/outer(us): %4llu/%-5llu ts:%lld.%09ld",
1162 			 field->seqnum,
1163 			 field->duration,
1164 			 field->outer_duration,
1165 			 (long long)field->timestamp.tv_sec,
1166 			 field->timestamp.tv_nsec);
1167 
1168 	if (field->nmi_count) {
1169 		/*
1170 		 * The generic sched_clock() is not NMI safe, thus
1171 		 * we only record the count and not the time.
1172 		 */
1173 		if (!IS_ENABLED(CONFIG_GENERIC_SCHED_CLOCK))
1174 			trace_seq_printf(s, " nmi-total:%llu",
1175 					 field->nmi_total_ts);
1176 		trace_seq_printf(s, " nmi-count:%u",
1177 				 field->nmi_count);
1178 	}
1179 
1180 	trace_seq_putc(s, '\n');
1181 
1182 	return trace_handle_return(s);
1183 }
1184 
1185 
1186 static enum print_line_t
1187 trace_hwlat_raw(struct trace_iterator *iter, int flags,
1188 		struct trace_event *event)
1189 {
1190 	struct hwlat_entry *field;
1191 	struct trace_seq *s = &iter->seq;
1192 
1193 	trace_assign_type(field, iter->ent);
1194 
1195 	trace_seq_printf(s, "%llu %lld %lld %09ld %u\n",
1196 			 field->duration,
1197 			 field->outer_duration,
1198 			 (long long)field->timestamp.tv_sec,
1199 			 field->timestamp.tv_nsec,
1200 			 field->seqnum);
1201 
1202 	return trace_handle_return(s);
1203 }
1204 
1205 static struct trace_event_functions trace_hwlat_funcs = {
1206 	.trace		= trace_hwlat_print,
1207 	.raw		= trace_hwlat_raw,
1208 };
1209 
1210 static struct trace_event trace_hwlat_event = {
1211 	.type		= TRACE_HWLAT,
1212 	.funcs		= &trace_hwlat_funcs,
1213 };
1214 
1215 /* TRACE_BPUTS */
1216 static enum print_line_t
1217 trace_bputs_print(struct trace_iterator *iter, int flags,
1218 		   struct trace_event *event)
1219 {
1220 	struct trace_entry *entry = iter->ent;
1221 	struct trace_seq *s = &iter->seq;
1222 	struct bputs_entry *field;
1223 
1224 	trace_assign_type(field, entry);
1225 
1226 	seq_print_ip_sym(s, field->ip, flags);
1227 	trace_seq_puts(s, ": ");
1228 	trace_seq_puts(s, field->str);
1229 
1230 	return trace_handle_return(s);
1231 }
1232 
1233 
1234 static enum print_line_t
1235 trace_bputs_raw(struct trace_iterator *iter, int flags,
1236 		struct trace_event *event)
1237 {
1238 	struct bputs_entry *field;
1239 	struct trace_seq *s = &iter->seq;
1240 
1241 	trace_assign_type(field, iter->ent);
1242 
1243 	trace_seq_printf(s, ": %lx : ", field->ip);
1244 	trace_seq_puts(s, field->str);
1245 
1246 	return trace_handle_return(s);
1247 }
1248 
1249 static struct trace_event_functions trace_bputs_funcs = {
1250 	.trace		= trace_bputs_print,
1251 	.raw		= trace_bputs_raw,
1252 };
1253 
1254 static struct trace_event trace_bputs_event = {
1255 	.type		= TRACE_BPUTS,
1256 	.funcs		= &trace_bputs_funcs,
1257 };
1258 
1259 /* TRACE_BPRINT */
1260 static enum print_line_t
1261 trace_bprint_print(struct trace_iterator *iter, int flags,
1262 		   struct trace_event *event)
1263 {
1264 	struct trace_entry *entry = iter->ent;
1265 	struct trace_seq *s = &iter->seq;
1266 	struct bprint_entry *field;
1267 
1268 	trace_assign_type(field, entry);
1269 
1270 	seq_print_ip_sym(s, field->ip, flags);
1271 	trace_seq_puts(s, ": ");
1272 	trace_seq_bprintf(s, field->fmt, field->buf);
1273 
1274 	return trace_handle_return(s);
1275 }
1276 
1277 
1278 static enum print_line_t
1279 trace_bprint_raw(struct trace_iterator *iter, int flags,
1280 		 struct trace_event *event)
1281 {
1282 	struct bprint_entry *field;
1283 	struct trace_seq *s = &iter->seq;
1284 
1285 	trace_assign_type(field, iter->ent);
1286 
1287 	trace_seq_printf(s, ": %lx : ", field->ip);
1288 	trace_seq_bprintf(s, field->fmt, field->buf);
1289 
1290 	return trace_handle_return(s);
1291 }
1292 
1293 static struct trace_event_functions trace_bprint_funcs = {
1294 	.trace		= trace_bprint_print,
1295 	.raw		= trace_bprint_raw,
1296 };
1297 
1298 static struct trace_event trace_bprint_event = {
1299 	.type		= TRACE_BPRINT,
1300 	.funcs		= &trace_bprint_funcs,
1301 };
1302 
1303 /* TRACE_PRINT */
1304 static enum print_line_t trace_print_print(struct trace_iterator *iter,
1305 					   int flags, struct trace_event *event)
1306 {
1307 	struct print_entry *field;
1308 	struct trace_seq *s = &iter->seq;
1309 
1310 	trace_assign_type(field, iter->ent);
1311 
1312 	seq_print_ip_sym(s, field->ip, flags);
1313 	trace_seq_printf(s, ": %s", field->buf);
1314 
1315 	return trace_handle_return(s);
1316 }
1317 
1318 static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags,
1319 					 struct trace_event *event)
1320 {
1321 	struct print_entry *field;
1322 
1323 	trace_assign_type(field, iter->ent);
1324 
1325 	trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf);
1326 
1327 	return trace_handle_return(&iter->seq);
1328 }
1329 
1330 static struct trace_event_functions trace_print_funcs = {
1331 	.trace		= trace_print_print,
1332 	.raw		= trace_print_raw,
1333 };
1334 
1335 static struct trace_event trace_print_event = {
1336 	.type	 	= TRACE_PRINT,
1337 	.funcs		= &trace_print_funcs,
1338 };
1339 
1340 static enum print_line_t trace_raw_data(struct trace_iterator *iter, int flags,
1341 					 struct trace_event *event)
1342 {
1343 	struct raw_data_entry *field;
1344 	int i;
1345 
1346 	trace_assign_type(field, iter->ent);
1347 
1348 	trace_seq_printf(&iter->seq, "# %x buf:", field->id);
1349 
1350 	for (i = 0; i < iter->ent_size - offsetof(struct raw_data_entry, buf); i++)
1351 		trace_seq_printf(&iter->seq, " %02x",
1352 				 (unsigned char)field->buf[i]);
1353 
1354 	trace_seq_putc(&iter->seq, '\n');
1355 
1356 	return trace_handle_return(&iter->seq);
1357 }
1358 
1359 static struct trace_event_functions trace_raw_data_funcs = {
1360 	.trace		= trace_raw_data,
1361 	.raw		= trace_raw_data,
1362 };
1363 
1364 static struct trace_event trace_raw_data_event = {
1365 	.type	 	= TRACE_RAW_DATA,
1366 	.funcs		= &trace_raw_data_funcs,
1367 };
1368 
1369 
1370 static struct trace_event *events[] __initdata = {
1371 	&trace_fn_event,
1372 	&trace_ctx_event,
1373 	&trace_wake_event,
1374 	&trace_stack_event,
1375 	&trace_user_stack_event,
1376 	&trace_bputs_event,
1377 	&trace_bprint_event,
1378 	&trace_print_event,
1379 	&trace_hwlat_event,
1380 	&trace_raw_data_event,
1381 	NULL
1382 };
1383 
1384 __init static int init_events(void)
1385 {
1386 	struct trace_event *event;
1387 	int i, ret;
1388 
1389 	for (i = 0; events[i]; i++) {
1390 		event = events[i];
1391 
1392 		ret = register_trace_event(event);
1393 		if (!ret) {
1394 			printk(KERN_WARNING "event %d failed to register\n",
1395 			       event->type);
1396 			WARN_ON_ONCE(1);
1397 		}
1398 	}
1399 
1400 	return 0;
1401 }
1402 early_initcall(init_events);
1403