1 /*
2  * trace_output.c
3  *
4  * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
5  *
6  */
7 
8 #include <linux/module.h>
9 #include <linux/mutex.h>
10 #include <linux/ftrace.h>
11 
12 #include "trace_output.h"
13 
14 /* must be a power of 2 */
15 #define EVENT_HASHSIZE	128
16 
17 DECLARE_RWSEM(trace_event_mutex);
18 
19 static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;
20 
21 static int next_event_type = __TRACE_LAST_TYPE + 1;
22 
trace_print_seq(struct seq_file * m,struct trace_seq * s)23 int trace_print_seq(struct seq_file *m, struct trace_seq *s)
24 {
25 	int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
26 	int ret;
27 
28 	ret = seq_write(m, s->buffer, len);
29 
30 	/*
31 	 * Only reset this buffer if we successfully wrote to the
32 	 * seq_file buffer.
33 	 */
34 	if (!ret)
35 		trace_seq_init(s);
36 
37 	return ret;
38 }
39 
trace_print_bprintk_msg_only(struct trace_iterator * iter)40 enum print_line_t trace_print_bprintk_msg_only(struct trace_iterator *iter)
41 {
42 	struct trace_seq *s = &iter->seq;
43 	struct trace_entry *entry = iter->ent;
44 	struct bprint_entry *field;
45 	int ret;
46 
47 	trace_assign_type(field, entry);
48 
49 	ret = trace_seq_bprintf(s, field->fmt, field->buf);
50 	if (!ret)
51 		return TRACE_TYPE_PARTIAL_LINE;
52 
53 	return TRACE_TYPE_HANDLED;
54 }
55 
trace_print_printk_msg_only(struct trace_iterator * iter)56 enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter)
57 {
58 	struct trace_seq *s = &iter->seq;
59 	struct trace_entry *entry = iter->ent;
60 	struct print_entry *field;
61 	int ret;
62 
63 	trace_assign_type(field, entry);
64 
65 	ret = trace_seq_printf(s, "%s", field->buf);
66 	if (!ret)
67 		return TRACE_TYPE_PARTIAL_LINE;
68 
69 	return TRACE_TYPE_HANDLED;
70 }
71 
72 /**
73  * trace_seq_printf - sequence printing of trace information
74  * @s: trace sequence descriptor
75  * @fmt: printf format string
76  *
77  * It returns 0 if the trace oversizes the buffer's free
78  * space, 1 otherwise.
79  *
80  * The tracer may use either sequence operations or its own
81  * copy to user routines. To simplify formating of a trace
82  * trace_seq_printf is used to store strings into a special
83  * buffer (@s). Then the output may be either used by
84  * the sequencer or pulled into another buffer.
85  */
86 int
trace_seq_printf(struct trace_seq * s,const char * fmt,...)87 trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
88 {
89 	int len = (PAGE_SIZE - 1) - s->len;
90 	va_list ap;
91 	int ret;
92 
93 	if (s->full || !len)
94 		return 0;
95 
96 	va_start(ap, fmt);
97 	ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
98 	va_end(ap);
99 
100 	/* If we can't write it all, don't bother writing anything */
101 	if (ret >= len) {
102 		s->full = 1;
103 		return 0;
104 	}
105 
106 	s->len += ret;
107 
108 	return 1;
109 }
110 EXPORT_SYMBOL_GPL(trace_seq_printf);
111 
112 /**
113  * trace_seq_vprintf - sequence printing of trace information
114  * @s: trace sequence descriptor
115  * @fmt: printf format string
116  *
117  * The tracer may use either sequence operations or its own
118  * copy to user routines. To simplify formating of a trace
119  * trace_seq_printf is used to store strings into a special
120  * buffer (@s). Then the output may be either used by
121  * the sequencer or pulled into another buffer.
122  */
123 int
trace_seq_vprintf(struct trace_seq * s,const char * fmt,va_list args)124 trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
125 {
126 	int len = (PAGE_SIZE - 1) - s->len;
127 	int ret;
128 
129 	if (s->full || !len)
130 		return 0;
131 
132 	ret = vsnprintf(s->buffer + s->len, len, fmt, args);
133 
134 	/* If we can't write it all, don't bother writing anything */
135 	if (ret >= len) {
136 		s->full = 1;
137 		return 0;
138 	}
139 
140 	s->len += ret;
141 
142 	return len;
143 }
144 EXPORT_SYMBOL_GPL(trace_seq_vprintf);
145 
trace_seq_bprintf(struct trace_seq * s,const char * fmt,const u32 * binary)146 int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
147 {
148 	int len = (PAGE_SIZE - 1) - s->len;
149 	int ret;
150 
151 	if (s->full || !len)
152 		return 0;
153 
154 	ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
155 
156 	/* If we can't write it all, don't bother writing anything */
157 	if (ret >= len) {
158 		s->full = 1;
159 		return 0;
160 	}
161 
162 	s->len += ret;
163 
164 	return len;
165 }
166 
167 /**
168  * trace_seq_puts - trace sequence printing of simple string
169  * @s: trace sequence descriptor
170  * @str: simple string to record
171  *
172  * The tracer may use either the sequence operations or its own
173  * copy to user routines. This function records a simple string
174  * into a special buffer (@s) for later retrieval by a sequencer
175  * or other mechanism.
176  */
trace_seq_puts(struct trace_seq * s,const char * str)177 int trace_seq_puts(struct trace_seq *s, const char *str)
178 {
179 	int len = strlen(str);
180 
181 	if (s->full)
182 		return 0;
183 
184 	if (len > ((PAGE_SIZE - 1) - s->len)) {
185 		s->full = 1;
186 		return 0;
187 	}
188 
189 	memcpy(s->buffer + s->len, str, len);
190 	s->len += len;
191 
192 	return len;
193 }
194 
trace_seq_putc(struct trace_seq * s,unsigned char c)195 int trace_seq_putc(struct trace_seq *s, unsigned char c)
196 {
197 	if (s->full)
198 		return 0;
199 
200 	if (s->len >= (PAGE_SIZE - 1)) {
201 		s->full = 1;
202 		return 0;
203 	}
204 
205 	s->buffer[s->len++] = c;
206 
207 	return 1;
208 }
209 EXPORT_SYMBOL(trace_seq_putc);
210 
trace_seq_putmem(struct trace_seq * s,const void * mem,size_t len)211 int trace_seq_putmem(struct trace_seq *s, const void *mem, size_t len)
212 {
213 	if (s->full)
214 		return 0;
215 
216 	if (len > ((PAGE_SIZE - 1) - s->len)) {
217 		s->full = 1;
218 		return 0;
219 	}
220 
221 	memcpy(s->buffer + s->len, mem, len);
222 	s->len += len;
223 
224 	return len;
225 }
226 
trace_seq_putmem_hex(struct trace_seq * s,const void * mem,size_t len)227 int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, size_t len)
228 {
229 	unsigned char hex[HEX_CHARS];
230 	const unsigned char *data = mem;
231 	int i, j;
232 
233 	if (s->full)
234 		return 0;
235 
236 #ifdef __BIG_ENDIAN
237 	for (i = 0, j = 0; i < len; i++) {
238 #else
239 	for (i = len-1, j = 0; i >= 0; i--) {
240 #endif
241 		hex[j++] = hex_asc_hi(data[i]);
242 		hex[j++] = hex_asc_lo(data[i]);
243 	}
244 	hex[j++] = ' ';
245 
246 	return trace_seq_putmem(s, hex, j);
247 }
248 
249 void *trace_seq_reserve(struct trace_seq *s, size_t len)
250 {
251 	void *ret;
252 
253 	if (s->full)
254 		return NULL;
255 
256 	if (len > ((PAGE_SIZE - 1) - s->len)) {
257 		s->full = 1;
258 		return NULL;
259 	}
260 
261 	ret = s->buffer + s->len;
262 	s->len += len;
263 
264 	return ret;
265 }
266 
267 int trace_seq_path(struct trace_seq *s, struct path *path)
268 {
269 	unsigned char *p;
270 
271 	if (s->full)
272 		return 0;
273 
274 	if (s->len >= (PAGE_SIZE - 1)) {
275 		s->full = 1;
276 		return 0;
277 	}
278 
279 	p = d_path(path, s->buffer + s->len, PAGE_SIZE - s->len);
280 	if (!IS_ERR(p)) {
281 		p = mangle_path(s->buffer + s->len, p, "\n");
282 		if (p) {
283 			s->len = p - s->buffer;
284 			return 1;
285 		}
286 	} else {
287 		s->buffer[s->len++] = '?';
288 		return 1;
289 	}
290 
291 	s->full = 1;
292 	return 0;
293 }
294 
295 const char *
296 ftrace_print_flags_seq(struct trace_seq *p, const char *delim,
297 		       unsigned long flags,
298 		       const struct trace_print_flags *flag_array)
299 {
300 	unsigned long mask;
301 	const char *str;
302 	const char *ret = p->buffer + p->len;
303 	int i;
304 
305 	for (i = 0;  flag_array[i].name && flags; i++) {
306 
307 		mask = flag_array[i].mask;
308 		if ((flags & mask) != mask)
309 			continue;
310 
311 		str = flag_array[i].name;
312 		flags &= ~mask;
313 		if (p->len && delim)
314 			trace_seq_puts(p, delim);
315 		trace_seq_puts(p, str);
316 	}
317 
318 	/* check for left over flags */
319 	if (flags) {
320 		if (p->len && delim)
321 			trace_seq_puts(p, delim);
322 		trace_seq_printf(p, "0x%lx", flags);
323 	}
324 
325 	trace_seq_putc(p, 0);
326 
327 	return ret;
328 }
329 EXPORT_SYMBOL(ftrace_print_flags_seq);
330 
331 const char *
332 ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val,
333 			 const struct trace_print_flags *symbol_array)
334 {
335 	int i;
336 	const char *ret = p->buffer + p->len;
337 
338 	for (i = 0;  symbol_array[i].name; i++) {
339 
340 		if (val != symbol_array[i].mask)
341 			continue;
342 
343 		trace_seq_puts(p, symbol_array[i].name);
344 		break;
345 	}
346 
347 	if (!p->len)
348 		trace_seq_printf(p, "0x%lx", val);
349 
350 	trace_seq_putc(p, 0);
351 
352 	return ret;
353 }
354 EXPORT_SYMBOL(ftrace_print_symbols_seq);
355 
356 const char *
357 ftrace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len)
358 {
359 	int i;
360 	const char *ret = p->buffer + p->len;
361 
362 	for (i = 0; i < buf_len; i++)
363 		trace_seq_printf(p, "%s%2.2x", i == 0 ? "" : " ", buf[i]);
364 
365 	trace_seq_putc(p, 0);
366 
367 	return ret;
368 }
369 EXPORT_SYMBOL(ftrace_print_hex_seq);
370 
371 #ifdef CONFIG_KRETPROBES
372 static inline const char *kretprobed(const char *name)
373 {
374 	static const char tramp_name[] = "kretprobe_trampoline";
375 	int size = sizeof(tramp_name);
376 
377 	if (strncmp(tramp_name, name, size) == 0)
378 		return "[unknown/kretprobe'd]";
379 	return name;
380 }
381 #else
382 static inline const char *kretprobed(const char *name)
383 {
384 	return name;
385 }
386 #endif /* CONFIG_KRETPROBES */
387 
388 static int
389 seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
390 {
391 #ifdef CONFIG_KALLSYMS
392 	char str[KSYM_SYMBOL_LEN];
393 	const char *name;
394 
395 	kallsyms_lookup(address, NULL, NULL, NULL, str);
396 
397 	name = kretprobed(str);
398 
399 	return trace_seq_printf(s, fmt, name);
400 #endif
401 	return 1;
402 }
403 
404 static int
405 seq_print_sym_offset(struct trace_seq *s, const char *fmt,
406 		     unsigned long address)
407 {
408 #ifdef CONFIG_KALLSYMS
409 	char str[KSYM_SYMBOL_LEN];
410 	const char *name;
411 
412 	sprint_symbol(str, address);
413 	name = kretprobed(str);
414 
415 	return trace_seq_printf(s, fmt, name);
416 #endif
417 	return 1;
418 }
419 
420 #ifndef CONFIG_64BIT
421 # define IP_FMT "%08lx"
422 #else
423 # define IP_FMT "%016lx"
424 #endif
425 
426 int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
427 		      unsigned long ip, unsigned long sym_flags)
428 {
429 	struct file *file = NULL;
430 	unsigned long vmstart = 0;
431 	int ret = 1;
432 
433 	if (s->full)
434 		return 0;
435 
436 	if (mm) {
437 		const struct vm_area_struct *vma;
438 
439 		down_read(&mm->mmap_sem);
440 		vma = find_vma(mm, ip);
441 		if (vma) {
442 			file = vma->vm_file;
443 			vmstart = vma->vm_start;
444 		}
445 		if (file) {
446 			ret = trace_seq_path(s, &file->f_path);
447 			if (ret)
448 				ret = trace_seq_printf(s, "[+0x%lx]",
449 						       ip - vmstart);
450 		}
451 		up_read(&mm->mmap_sem);
452 	}
453 	if (ret && ((sym_flags & TRACE_ITER_SYM_ADDR) || !file))
454 		ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
455 	return ret;
456 }
457 
458 int
459 seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s,
460 		      unsigned long sym_flags)
461 {
462 	struct mm_struct *mm = NULL;
463 	int ret = 1;
464 	unsigned int i;
465 
466 	if (trace_flags & TRACE_ITER_SYM_USEROBJ) {
467 		struct task_struct *task;
468 		/*
469 		 * we do the lookup on the thread group leader,
470 		 * since individual threads might have already quit!
471 		 */
472 		rcu_read_lock();
473 		task = find_task_by_vpid(entry->tgid);
474 		if (task)
475 			mm = get_task_mm(task);
476 		rcu_read_unlock();
477 	}
478 
479 	for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
480 		unsigned long ip = entry->caller[i];
481 
482 		if (ip == ULONG_MAX || !ret)
483 			break;
484 		if (ret)
485 			ret = trace_seq_puts(s, " => ");
486 		if (!ip) {
487 			if (ret)
488 				ret = trace_seq_puts(s, "??");
489 			if (ret)
490 				ret = trace_seq_puts(s, "\n");
491 			continue;
492 		}
493 		if (!ret)
494 			break;
495 		if (ret)
496 			ret = seq_print_user_ip(s, mm, ip, sym_flags);
497 		ret = trace_seq_puts(s, "\n");
498 	}
499 
500 	if (mm)
501 		mmput(mm);
502 	return ret;
503 }
504 
505 int
506 seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
507 {
508 	int ret;
509 
510 	if (!ip)
511 		return trace_seq_printf(s, "0");
512 
513 	if (sym_flags & TRACE_ITER_SYM_OFFSET)
514 		ret = seq_print_sym_offset(s, "%s", ip);
515 	else
516 		ret = seq_print_sym_short(s, "%s", ip);
517 
518 	if (!ret)
519 		return 0;
520 
521 	if (sym_flags & TRACE_ITER_SYM_ADDR)
522 		ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
523 	return ret;
524 }
525 
526 /**
527  * trace_print_lat_fmt - print the irq, preempt and lockdep fields
528  * @s: trace seq struct to write to
529  * @entry: The trace entry field from the ring buffer
530  *
531  * Prints the generic fields of irqs off, in hard or softirq, preempt
532  * count.
533  */
534 int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
535 {
536 	char hardsoft_irq;
537 	char need_resched;
538 	char irqs_off;
539 	int hardirq;
540 	int softirq;
541 	int ret;
542 
543 	hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
544 	softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
545 
546 	irqs_off =
547 		(entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
548 		(entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' :
549 		'.';
550 	need_resched =
551 		(entry->flags & TRACE_FLAG_NEED_RESCHED) ? 'N' : '.';
552 	hardsoft_irq =
553 		(hardirq && softirq) ? 'H' :
554 		hardirq ? 'h' :
555 		softirq ? 's' :
556 		'.';
557 
558 	if (!trace_seq_printf(s, "%c%c%c",
559 			      irqs_off, need_resched, hardsoft_irq))
560 		return 0;
561 
562 	if (entry->preempt_count)
563 		ret = trace_seq_printf(s, "%x", entry->preempt_count);
564 	else
565 		ret = trace_seq_putc(s, '.');
566 
567 	return ret;
568 }
569 
570 static int
571 lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
572 {
573 	char comm[TASK_COMM_LEN];
574 
575 	trace_find_cmdline(entry->pid, comm);
576 
577 	if (!trace_seq_printf(s, "%8.8s-%-5d %3d",
578 			      comm, entry->pid, cpu))
579 		return 0;
580 
581 	return trace_print_lat_fmt(s, entry);
582 }
583 
584 static unsigned long preempt_mark_thresh = 100;
585 
586 static int
587 lat_print_timestamp(struct trace_seq *s, u64 abs_usecs,
588 		    unsigned long rel_usecs)
589 {
590 	return trace_seq_printf(s, " %4lldus%c: ", abs_usecs,
591 				rel_usecs > preempt_mark_thresh ? '!' :
592 				  rel_usecs > 1 ? '+' : ' ');
593 }
594 
595 int trace_print_context(struct trace_iterator *iter)
596 {
597 	struct trace_seq *s = &iter->seq;
598 	struct trace_entry *entry = iter->ent;
599 	unsigned long long t = ns2usecs(iter->ts);
600 	unsigned long usec_rem = do_div(t, USEC_PER_SEC);
601 	unsigned long secs = (unsigned long)t;
602 	char comm[TASK_COMM_LEN];
603 
604 	trace_find_cmdline(entry->pid, comm);
605 
606 	return trace_seq_printf(s, "%16s-%-5d [%03d] %5lu.%06lu: ",
607 				comm, entry->pid, iter->cpu, secs, usec_rem);
608 }
609 
610 int trace_print_lat_context(struct trace_iterator *iter)
611 {
612 	u64 next_ts;
613 	int ret;
614 	struct trace_seq *s = &iter->seq;
615 	struct trace_entry *entry = iter->ent,
616 			   *next_entry = trace_find_next_entry(iter, NULL,
617 							       &next_ts);
618 	unsigned long verbose = (trace_flags & TRACE_ITER_VERBOSE);
619 	unsigned long abs_usecs = ns2usecs(iter->ts - iter->tr->time_start);
620 	unsigned long rel_usecs;
621 
622 	if (!next_entry)
623 		next_ts = iter->ts;
624 	rel_usecs = ns2usecs(next_ts - iter->ts);
625 
626 	if (verbose) {
627 		char comm[TASK_COMM_LEN];
628 
629 		trace_find_cmdline(entry->pid, comm);
630 
631 		ret = trace_seq_printf(s, "%16s %5d %3d %d %08x %08lx [%08llx]"
632 				       " %ld.%03ldms (+%ld.%03ldms): ", comm,
633 				       entry->pid, iter->cpu, entry->flags,
634 				       entry->preempt_count, iter->idx,
635 				       ns2usecs(iter->ts),
636 				       abs_usecs / USEC_PER_MSEC,
637 				       abs_usecs % USEC_PER_MSEC,
638 				       rel_usecs / USEC_PER_MSEC,
639 				       rel_usecs % USEC_PER_MSEC);
640 	} else {
641 		ret = lat_print_generic(s, entry, iter->cpu);
642 		if (ret)
643 			ret = lat_print_timestamp(s, abs_usecs, rel_usecs);
644 	}
645 
646 	return ret;
647 }
648 
649 static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
650 
651 static int task_state_char(unsigned long state)
652 {
653 	int bit = state ? __ffs(state) + 1 : 0;
654 
655 	return bit < sizeof(state_to_char) - 1 ? state_to_char[bit] : '?';
656 }
657 
658 /**
659  * ftrace_find_event - find a registered event
660  * @type: the type of event to look for
661  *
662  * Returns an event of type @type otherwise NULL
663  * Called with trace_event_read_lock() held.
664  */
665 struct trace_event *ftrace_find_event(int type)
666 {
667 	struct trace_event *event;
668 	struct hlist_node *n;
669 	unsigned key;
670 
671 	key = type & (EVENT_HASHSIZE - 1);
672 
673 	hlist_for_each_entry(event, n, &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) > FTRACE_MAX_EVENT)
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_mutex);
714 }
715 
716 void trace_event_read_unlock(void)
717 {
718 	up_read(&trace_event_mutex);
719 }
720 
721 /**
722  * register_ftrace_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_ftrace_event(struct trace_event *event)
737 {
738 	unsigned key;
739 	int ret = 0;
740 
741 	down_write(&trace_event_mutex);
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 > FTRACE_MAX_EVENT) {
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_mutex);
797 
798 	return ret;
799 }
800 EXPORT_SYMBOL_GPL(register_ftrace_event);
801 
802 /*
803  * Used by module code with the trace_event_mutex held for write.
804  */
805 int __unregister_ftrace_event(struct trace_event *event)
806 {
807 	hlist_del(&event->node);
808 	list_del(&event->list);
809 	return 0;
810 }
811 
812 /**
813  * unregister_ftrace_event - remove a no longer used event
814  * @event: the event to remove
815  */
816 int unregister_ftrace_event(struct trace_event *event)
817 {
818 	down_write(&trace_event_mutex);
819 	__unregister_ftrace_event(event);
820 	up_write(&trace_event_mutex);
821 
822 	return 0;
823 }
824 EXPORT_SYMBOL_GPL(unregister_ftrace_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 	return TRACE_TYPE_HANDLED;
834 }
835 
836 /* TRACE_FN */
837 static enum print_line_t trace_fn_trace(struct trace_iterator *iter, int flags,
838 					struct trace_event *event)
839 {
840 	struct ftrace_entry *field;
841 	struct trace_seq *s = &iter->seq;
842 
843 	trace_assign_type(field, iter->ent);
844 
845 	if (!seq_print_ip_sym(s, field->ip, flags))
846 		goto partial;
847 
848 	if ((flags & TRACE_ITER_PRINT_PARENT) && field->parent_ip) {
849 		if (!trace_seq_printf(s, " <-"))
850 			goto partial;
851 		if (!seq_print_ip_sym(s,
852 				      field->parent_ip,
853 				      flags))
854 			goto partial;
855 	}
856 	if (!trace_seq_printf(s, "\n"))
857 		goto partial;
858 
859 	return TRACE_TYPE_HANDLED;
860 
861  partial:
862 	return TRACE_TYPE_PARTIAL_LINE;
863 }
864 
865 static enum print_line_t trace_fn_raw(struct trace_iterator *iter, int flags,
866 				      struct trace_event *event)
867 {
868 	struct ftrace_entry *field;
869 
870 	trace_assign_type(field, iter->ent);
871 
872 	if (!trace_seq_printf(&iter->seq, "%lx %lx\n",
873 			      field->ip,
874 			      field->parent_ip))
875 		return TRACE_TYPE_PARTIAL_LINE;
876 
877 	return TRACE_TYPE_HANDLED;
878 }
879 
880 static enum print_line_t trace_fn_hex(struct trace_iterator *iter, int flags,
881 				      struct trace_event *event)
882 {
883 	struct ftrace_entry *field;
884 	struct trace_seq *s = &iter->seq;
885 
886 	trace_assign_type(field, iter->ent);
887 
888 	SEQ_PUT_HEX_FIELD_RET(s, field->ip);
889 	SEQ_PUT_HEX_FIELD_RET(s, field->parent_ip);
890 
891 	return TRACE_TYPE_HANDLED;
892 }
893 
894 static enum print_line_t trace_fn_bin(struct trace_iterator *iter, int flags,
895 				      struct trace_event *event)
896 {
897 	struct ftrace_entry *field;
898 	struct trace_seq *s = &iter->seq;
899 
900 	trace_assign_type(field, iter->ent);
901 
902 	SEQ_PUT_FIELD_RET(s, field->ip);
903 	SEQ_PUT_FIELD_RET(s, field->parent_ip);
904 
905 	return TRACE_TYPE_HANDLED;
906 }
907 
908 static struct trace_event_functions trace_fn_funcs = {
909 	.trace		= trace_fn_trace,
910 	.raw		= trace_fn_raw,
911 	.hex		= trace_fn_hex,
912 	.binary		= trace_fn_bin,
913 };
914 
915 static struct trace_event trace_fn_event = {
916 	.type		= TRACE_FN,
917 	.funcs		= &trace_fn_funcs,
918 };
919 
920 /* TRACE_CTX an TRACE_WAKE */
921 static enum print_line_t trace_ctxwake_print(struct trace_iterator *iter,
922 					     char *delim)
923 {
924 	struct ctx_switch_entry *field;
925 	char comm[TASK_COMM_LEN];
926 	int S, T;
927 
928 
929 	trace_assign_type(field, iter->ent);
930 
931 	T = task_state_char(field->next_state);
932 	S = task_state_char(field->prev_state);
933 	trace_find_cmdline(field->next_pid, comm);
934 	if (!trace_seq_printf(&iter->seq,
935 			      " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
936 			      field->prev_pid,
937 			      field->prev_prio,
938 			      S, delim,
939 			      field->next_cpu,
940 			      field->next_pid,
941 			      field->next_prio,
942 			      T, comm))
943 		return TRACE_TYPE_PARTIAL_LINE;
944 
945 	return TRACE_TYPE_HANDLED;
946 }
947 
948 static enum print_line_t trace_ctx_print(struct trace_iterator *iter, int flags,
949 					 struct trace_event *event)
950 {
951 	return trace_ctxwake_print(iter, "==>");
952 }
953 
954 static enum print_line_t trace_wake_print(struct trace_iterator *iter,
955 					  int flags, struct trace_event *event)
956 {
957 	return trace_ctxwake_print(iter, "  +");
958 }
959 
960 static int trace_ctxwake_raw(struct trace_iterator *iter, char S)
961 {
962 	struct ctx_switch_entry *field;
963 	int T;
964 
965 	trace_assign_type(field, iter->ent);
966 
967 	if (!S)
968 		S = task_state_char(field->prev_state);
969 	T = task_state_char(field->next_state);
970 	if (!trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
971 			      field->prev_pid,
972 			      field->prev_prio,
973 			      S,
974 			      field->next_cpu,
975 			      field->next_pid,
976 			      field->next_prio,
977 			      T))
978 		return TRACE_TYPE_PARTIAL_LINE;
979 
980 	return TRACE_TYPE_HANDLED;
981 }
982 
983 static enum print_line_t trace_ctx_raw(struct trace_iterator *iter, int flags,
984 				       struct trace_event *event)
985 {
986 	return trace_ctxwake_raw(iter, 0);
987 }
988 
989 static enum print_line_t trace_wake_raw(struct trace_iterator *iter, int flags,
990 					struct trace_event *event)
991 {
992 	return trace_ctxwake_raw(iter, '+');
993 }
994 
995 
996 static int trace_ctxwake_hex(struct trace_iterator *iter, char S)
997 {
998 	struct ctx_switch_entry *field;
999 	struct trace_seq *s = &iter->seq;
1000 	int T;
1001 
1002 	trace_assign_type(field, iter->ent);
1003 
1004 	if (!S)
1005 		S = task_state_char(field->prev_state);
1006 	T = task_state_char(field->next_state);
1007 
1008 	SEQ_PUT_HEX_FIELD_RET(s, field->prev_pid);
1009 	SEQ_PUT_HEX_FIELD_RET(s, field->prev_prio);
1010 	SEQ_PUT_HEX_FIELD_RET(s, S);
1011 	SEQ_PUT_HEX_FIELD_RET(s, field->next_cpu);
1012 	SEQ_PUT_HEX_FIELD_RET(s, field->next_pid);
1013 	SEQ_PUT_HEX_FIELD_RET(s, field->next_prio);
1014 	SEQ_PUT_HEX_FIELD_RET(s, T);
1015 
1016 	return TRACE_TYPE_HANDLED;
1017 }
1018 
1019 static enum print_line_t trace_ctx_hex(struct trace_iterator *iter, int flags,
1020 				       struct trace_event *event)
1021 {
1022 	return trace_ctxwake_hex(iter, 0);
1023 }
1024 
1025 static enum print_line_t trace_wake_hex(struct trace_iterator *iter, int flags,
1026 					struct trace_event *event)
1027 {
1028 	return trace_ctxwake_hex(iter, '+');
1029 }
1030 
1031 static enum print_line_t trace_ctxwake_bin(struct trace_iterator *iter,
1032 					   int flags, struct trace_event *event)
1033 {
1034 	struct ctx_switch_entry *field;
1035 	struct trace_seq *s = &iter->seq;
1036 
1037 	trace_assign_type(field, iter->ent);
1038 
1039 	SEQ_PUT_FIELD_RET(s, field->prev_pid);
1040 	SEQ_PUT_FIELD_RET(s, field->prev_prio);
1041 	SEQ_PUT_FIELD_RET(s, field->prev_state);
1042 	SEQ_PUT_FIELD_RET(s, field->next_pid);
1043 	SEQ_PUT_FIELD_RET(s, field->next_prio);
1044 	SEQ_PUT_FIELD_RET(s, field->next_state);
1045 
1046 	return TRACE_TYPE_HANDLED;
1047 }
1048 
1049 static struct trace_event_functions trace_ctx_funcs = {
1050 	.trace		= trace_ctx_print,
1051 	.raw		= trace_ctx_raw,
1052 	.hex		= trace_ctx_hex,
1053 	.binary		= trace_ctxwake_bin,
1054 };
1055 
1056 static struct trace_event trace_ctx_event = {
1057 	.type		= TRACE_CTX,
1058 	.funcs		= &trace_ctx_funcs,
1059 };
1060 
1061 static struct trace_event_functions trace_wake_funcs = {
1062 	.trace		= trace_wake_print,
1063 	.raw		= trace_wake_raw,
1064 	.hex		= trace_wake_hex,
1065 	.binary		= trace_ctxwake_bin,
1066 };
1067 
1068 static struct trace_event trace_wake_event = {
1069 	.type		= TRACE_WAKE,
1070 	.funcs		= &trace_wake_funcs,
1071 };
1072 
1073 /* TRACE_STACK */
1074 
1075 static enum print_line_t trace_stack_print(struct trace_iterator *iter,
1076 					   int flags, struct trace_event *event)
1077 {
1078 	struct stack_entry *field;
1079 	struct trace_seq *s = &iter->seq;
1080 	int i;
1081 
1082 	trace_assign_type(field, iter->ent);
1083 
1084 	if (!trace_seq_puts(s, "<stack trace>\n"))
1085 		goto partial;
1086 	for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
1087 		if (!field->caller[i] || (field->caller[i] == ULONG_MAX))
1088 			break;
1089 		if (!trace_seq_puts(s, " => "))
1090 			goto partial;
1091 
1092 		if (!seq_print_ip_sym(s, field->caller[i], flags))
1093 			goto partial;
1094 		if (!trace_seq_puts(s, "\n"))
1095 			goto partial;
1096 	}
1097 
1098 	return TRACE_TYPE_HANDLED;
1099 
1100  partial:
1101 	return TRACE_TYPE_PARTIAL_LINE;
1102 }
1103 
1104 static struct trace_event_functions trace_stack_funcs = {
1105 	.trace		= trace_stack_print,
1106 };
1107 
1108 static struct trace_event trace_stack_event = {
1109 	.type		= TRACE_STACK,
1110 	.funcs		= &trace_stack_funcs,
1111 };
1112 
1113 /* TRACE_USER_STACK */
1114 static enum print_line_t trace_user_stack_print(struct trace_iterator *iter,
1115 						int flags, struct trace_event *event)
1116 {
1117 	struct userstack_entry *field;
1118 	struct trace_seq *s = &iter->seq;
1119 
1120 	trace_assign_type(field, iter->ent);
1121 
1122 	if (!trace_seq_puts(s, "<user stack trace>\n"))
1123 		goto partial;
1124 
1125 	if (!seq_print_userip_objs(field, s, flags))
1126 		goto partial;
1127 
1128 	return TRACE_TYPE_HANDLED;
1129 
1130  partial:
1131 	return TRACE_TYPE_PARTIAL_LINE;
1132 }
1133 
1134 static struct trace_event_functions trace_user_stack_funcs = {
1135 	.trace		= trace_user_stack_print,
1136 };
1137 
1138 static struct trace_event trace_user_stack_event = {
1139 	.type		= TRACE_USER_STACK,
1140 	.funcs		= &trace_user_stack_funcs,
1141 };
1142 
1143 /* TRACE_BPRINT */
1144 static enum print_line_t
1145 trace_bprint_print(struct trace_iterator *iter, int flags,
1146 		   struct trace_event *event)
1147 {
1148 	struct trace_entry *entry = iter->ent;
1149 	struct trace_seq *s = &iter->seq;
1150 	struct bprint_entry *field;
1151 
1152 	trace_assign_type(field, entry);
1153 
1154 	if (!seq_print_ip_sym(s, field->ip, flags))
1155 		goto partial;
1156 
1157 	if (!trace_seq_puts(s, ": "))
1158 		goto partial;
1159 
1160 	if (!trace_seq_bprintf(s, field->fmt, field->buf))
1161 		goto partial;
1162 
1163 	return TRACE_TYPE_HANDLED;
1164 
1165  partial:
1166 	return TRACE_TYPE_PARTIAL_LINE;
1167 }
1168 
1169 
1170 static enum print_line_t
1171 trace_bprint_raw(struct trace_iterator *iter, int flags,
1172 		 struct trace_event *event)
1173 {
1174 	struct bprint_entry *field;
1175 	struct trace_seq *s = &iter->seq;
1176 
1177 	trace_assign_type(field, iter->ent);
1178 
1179 	if (!trace_seq_printf(s, ": %lx : ", field->ip))
1180 		goto partial;
1181 
1182 	if (!trace_seq_bprintf(s, field->fmt, field->buf))
1183 		goto partial;
1184 
1185 	return TRACE_TYPE_HANDLED;
1186 
1187  partial:
1188 	return TRACE_TYPE_PARTIAL_LINE;
1189 }
1190 
1191 static struct trace_event_functions trace_bprint_funcs = {
1192 	.trace		= trace_bprint_print,
1193 	.raw		= trace_bprint_raw,
1194 };
1195 
1196 static struct trace_event trace_bprint_event = {
1197 	.type		= TRACE_BPRINT,
1198 	.funcs		= &trace_bprint_funcs,
1199 };
1200 
1201 /* TRACE_PRINT */
1202 static enum print_line_t trace_print_print(struct trace_iterator *iter,
1203 					   int flags, struct trace_event *event)
1204 {
1205 	struct print_entry *field;
1206 	struct trace_seq *s = &iter->seq;
1207 
1208 	trace_assign_type(field, iter->ent);
1209 
1210 	if (!seq_print_ip_sym(s, field->ip, flags))
1211 		goto partial;
1212 
1213 	if (!trace_seq_printf(s, ": %s", field->buf))
1214 		goto partial;
1215 
1216 	return TRACE_TYPE_HANDLED;
1217 
1218  partial:
1219 	return TRACE_TYPE_PARTIAL_LINE;
1220 }
1221 
1222 static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags,
1223 					 struct trace_event *event)
1224 {
1225 	struct print_entry *field;
1226 
1227 	trace_assign_type(field, iter->ent);
1228 
1229 	if (!trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf))
1230 		goto partial;
1231 
1232 	return TRACE_TYPE_HANDLED;
1233 
1234  partial:
1235 	return TRACE_TYPE_PARTIAL_LINE;
1236 }
1237 
1238 static struct trace_event_functions trace_print_funcs = {
1239 	.trace		= trace_print_print,
1240 	.raw		= trace_print_raw,
1241 };
1242 
1243 static struct trace_event trace_print_event = {
1244 	.type	 	= TRACE_PRINT,
1245 	.funcs		= &trace_print_funcs,
1246 };
1247 
1248 
1249 static struct trace_event *events[] __initdata = {
1250 	&trace_fn_event,
1251 	&trace_ctx_event,
1252 	&trace_wake_event,
1253 	&trace_stack_event,
1254 	&trace_user_stack_event,
1255 	&trace_bprint_event,
1256 	&trace_print_event,
1257 	NULL
1258 };
1259 
1260 __init static int init_events(void)
1261 {
1262 	struct trace_event *event;
1263 	int i, ret;
1264 
1265 	for (i = 0; events[i]; i++) {
1266 		event = events[i];
1267 
1268 		ret = register_ftrace_event(event);
1269 		if (!ret) {
1270 			printk(KERN_WARNING "event %d failed to register\n",
1271 			       event->type);
1272 			WARN_ON_ONCE(1);
1273 		}
1274 	}
1275 
1276 	return 0;
1277 }
1278 device_initcall(init_events);
1279