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ftrace: fix __trace_special()
[deliverable/linux.git] / kernel / trace / trace.c
1 /*
2 * ring buffer based function tracer
3 *
4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
6 *
7 * Originally taken from the RT patch by:
8 * Arnaldo Carvalho de Melo <acme@redhat.com>
9 *
10 * Based on code from the latency_tracer, that is:
11 * Copyright (C) 2004-2006 Ingo Molnar
12 * Copyright (C) 2004 William Lee Irwin III
13 */
14 #include <linux/utsrelease.h>
15 #include <linux/kallsyms.h>
16 #include <linux/seq_file.h>
17 #include <linux/debugfs.h>
18 #include <linux/pagemap.h>
19 #include <linux/hardirq.h>
20 #include <linux/linkage.h>
21 #include <linux/uaccess.h>
22 #include <linux/ftrace.h>
23 #include <linux/module.h>
24 #include <linux/percpu.h>
25 #include <linux/ctype.h>
26 #include <linux/init.h>
27 #include <linux/poll.h>
28 #include <linux/gfp.h>
29 #include <linux/fs.h>
30
31 #include <linux/stacktrace.h>
32
33 #include "trace.h"
34
35 unsigned long __read_mostly tracing_max_latency = (cycle_t)ULONG_MAX;
36 unsigned long __read_mostly tracing_thresh;
37
38 static int tracing_disabled = 1;
39
40 static long
41 ns2usecs(cycle_t nsec)
42 {
43 nsec += 500;
44 do_div(nsec, 1000);
45 return nsec;
46 }
47
48 cycle_t ftrace_now(int cpu)
49 {
50 return cpu_clock(cpu);
51 }
52
53 static struct trace_array global_trace;
54
55 static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
56
57 static struct trace_array max_tr;
58
59 static DEFINE_PER_CPU(struct trace_array_cpu, max_data);
60
61 static int tracer_enabled = 1;
62 static unsigned long trace_nr_entries = 65536UL;
63
64 static struct tracer *trace_types __read_mostly;
65 static struct tracer *current_trace __read_mostly;
66 static int max_tracer_type_len;
67
68 static DEFINE_MUTEX(trace_types_lock);
69 static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
70
71 unsigned long trace_flags = TRACE_ITER_PRINT_PARENT;
72
73 void trace_wake_up(void)
74 {
75 /*
76 * The runqueue_is_locked() can fail, but this is the best we
77 * have for now:
78 */
79 if (!(trace_flags & TRACE_ITER_BLOCK) && !runqueue_is_locked())
80 wake_up(&trace_wait);
81 }
82
83 #define ENTRIES_PER_PAGE (PAGE_SIZE / sizeof(struct trace_entry))
84
85 static int __init set_nr_entries(char *str)
86 {
87 if (!str)
88 return 0;
89 trace_nr_entries = simple_strtoul(str, &str, 0);
90 return 1;
91 }
92 __setup("trace_entries=", set_nr_entries);
93
94 unsigned long nsecs_to_usecs(unsigned long nsecs)
95 {
96 return nsecs / 1000;
97 }
98
99 enum trace_type {
100 __TRACE_FIRST_TYPE = 0,
101
102 TRACE_FN,
103 TRACE_CTX,
104 TRACE_WAKE,
105 TRACE_STACK,
106 TRACE_SPECIAL,
107
108 __TRACE_LAST_TYPE
109 };
110
111 enum trace_flag_type {
112 TRACE_FLAG_IRQS_OFF = 0x01,
113 TRACE_FLAG_NEED_RESCHED = 0x02,
114 TRACE_FLAG_HARDIRQ = 0x04,
115 TRACE_FLAG_SOFTIRQ = 0x08,
116 };
117
118 #define TRACE_ITER_SYM_MASK \
119 (TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR)
120
121 /* These must match the bit postions above */
122 static const char *trace_options[] = {
123 "print-parent",
124 "sym-offset",
125 "sym-addr",
126 "verbose",
127 "raw",
128 "hex",
129 "bin",
130 "block",
131 "stacktrace",
132 NULL
133 };
134
135 static DEFINE_SPINLOCK(ftrace_max_lock);
136
137 /*
138 * Copy the new maximum trace into the separate maximum-trace
139 * structure. (this way the maximum trace is permanently saved,
140 * for later retrieval via /debugfs/tracing/latency_trace)
141 */
142 static void
143 __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
144 {
145 struct trace_array_cpu *data = tr->data[cpu];
146
147 max_tr.cpu = cpu;
148 max_tr.time_start = data->preempt_timestamp;
149
150 data = max_tr.data[cpu];
151 data->saved_latency = tracing_max_latency;
152
153 memcpy(data->comm, tsk->comm, TASK_COMM_LEN);
154 data->pid = tsk->pid;
155 data->uid = tsk->uid;
156 data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
157 data->policy = tsk->policy;
158 data->rt_priority = tsk->rt_priority;
159
160 /* record this tasks comm */
161 tracing_record_cmdline(current);
162 }
163
164 void check_pages(struct trace_array_cpu *data)
165 {
166 struct page *page, *tmp;
167
168 BUG_ON(data->trace_pages.next->prev != &data->trace_pages);
169 BUG_ON(data->trace_pages.prev->next != &data->trace_pages);
170
171 list_for_each_entry_safe(page, tmp, &data->trace_pages, lru) {
172 BUG_ON(page->lru.next->prev != &page->lru);
173 BUG_ON(page->lru.prev->next != &page->lru);
174 }
175 }
176
177 void *head_page(struct trace_array_cpu *data)
178 {
179 struct page *page;
180
181 check_pages(data);
182 if (list_empty(&data->trace_pages))
183 return NULL;
184
185 page = list_entry(data->trace_pages.next, struct page, lru);
186 BUG_ON(&page->lru == &data->trace_pages);
187
188 return page_address(page);
189 }
190
191 static int
192 trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
193 {
194 int len = (PAGE_SIZE - 1) - s->len;
195 va_list ap;
196 int ret;
197
198 if (!len)
199 return 0;
200
201 va_start(ap, fmt);
202 ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
203 va_end(ap);
204
205 /* If we can't write it all, don't bother writing anything */
206 if (ret > len)
207 return 0;
208
209 s->len += ret;
210
211 return len;
212 }
213
214 static int
215 trace_seq_puts(struct trace_seq *s, const char *str)
216 {
217 int len = strlen(str);
218
219 if (len > ((PAGE_SIZE - 1) - s->len))
220 return 0;
221
222 memcpy(s->buffer + s->len, str, len);
223 s->len += len;
224
225 return len;
226 }
227
228 static int
229 trace_seq_putc(struct trace_seq *s, unsigned char c)
230 {
231 if (s->len >= (PAGE_SIZE - 1))
232 return 0;
233
234 s->buffer[s->len++] = c;
235
236 return 1;
237 }
238
239 static int
240 trace_seq_putmem(struct trace_seq *s, void *mem, size_t len)
241 {
242 if (len > ((PAGE_SIZE - 1) - s->len))
243 return 0;
244
245 memcpy(s->buffer + s->len, mem, len);
246 s->len += len;
247
248 return len;
249 }
250
251 #define HEX_CHARS 17
252
253 static int
254 trace_seq_putmem_hex(struct trace_seq *s, void *mem, size_t len)
255 {
256 unsigned char hex[HEX_CHARS];
257 unsigned char *data;
258 unsigned char byte;
259 int i, j;
260
261 BUG_ON(len >= HEX_CHARS);
262
263 data = mem;
264
265 #ifdef __BIG_ENDIAN
266 for (i = 0, j = 0; i < len; i++) {
267 #else
268 for (i = len-1, j = 0; i >= 0; i--) {
269 #endif
270 byte = data[i];
271
272 hex[j] = byte & 0x0f;
273 if (hex[j] >= 10)
274 hex[j] += 'a' - 10;
275 else
276 hex[j] += '0';
277 j++;
278
279 hex[j] = byte >> 4;
280 if (hex[j] >= 10)
281 hex[j] += 'a' - 10;
282 else
283 hex[j] += '0';
284 j++;
285 }
286 hex[j] = ' ';
287 j++;
288
289 return trace_seq_putmem(s, hex, j);
290 }
291
292 static void
293 trace_seq_reset(struct trace_seq *s)
294 {
295 s->len = 0;
296 }
297
298 static void
299 trace_print_seq(struct seq_file *m, struct trace_seq *s)
300 {
301 int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
302
303 s->buffer[len] = 0;
304 seq_puts(m, s->buffer);
305
306 trace_seq_reset(s);
307 }
308
309 static void
310 flip_trace(struct trace_array_cpu *tr1, struct trace_array_cpu *tr2)
311 {
312 struct list_head flip_pages;
313
314 INIT_LIST_HEAD(&flip_pages);
315
316 memcpy(&tr1->trace_head_idx, &tr2->trace_head_idx,
317 sizeof(struct trace_array_cpu) -
318 offsetof(struct trace_array_cpu, trace_head_idx));
319
320 check_pages(tr1);
321 check_pages(tr2);
322 list_splice_init(&tr1->trace_pages, &flip_pages);
323 list_splice_init(&tr2->trace_pages, &tr1->trace_pages);
324 list_splice_init(&flip_pages, &tr2->trace_pages);
325 BUG_ON(!list_empty(&flip_pages));
326 check_pages(tr1);
327 check_pages(tr2);
328 }
329
330 void
331 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
332 {
333 struct trace_array_cpu *data;
334 int i;
335
336 WARN_ON_ONCE(!irqs_disabled());
337 spin_lock(&ftrace_max_lock);
338 /* clear out all the previous traces */
339 for_each_possible_cpu(i) {
340 data = tr->data[i];
341 flip_trace(max_tr.data[i], data);
342 tracing_reset(data);
343 }
344
345 __update_max_tr(tr, tsk, cpu);
346 spin_unlock(&ftrace_max_lock);
347 }
348
349 /**
350 * update_max_tr_single - only copy one trace over, and reset the rest
351 * @tr - tracer
352 * @tsk - task with the latency
353 * @cpu - the cpu of the buffer to copy.
354 */
355 void
356 update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
357 {
358 struct trace_array_cpu *data = tr->data[cpu];
359 int i;
360
361 WARN_ON_ONCE(!irqs_disabled());
362 spin_lock(&ftrace_max_lock);
363 for_each_possible_cpu(i)
364 tracing_reset(max_tr.data[i]);
365
366 flip_trace(max_tr.data[cpu], data);
367 tracing_reset(data);
368
369 __update_max_tr(tr, tsk, cpu);
370 spin_unlock(&ftrace_max_lock);
371 }
372
373 int register_tracer(struct tracer *type)
374 {
375 struct tracer *t;
376 int len;
377 int ret = 0;
378
379 if (!type->name) {
380 pr_info("Tracer must have a name\n");
381 return -1;
382 }
383
384 mutex_lock(&trace_types_lock);
385 for (t = trace_types; t; t = t->next) {
386 if (strcmp(type->name, t->name) == 0) {
387 /* already found */
388 pr_info("Trace %s already registered\n",
389 type->name);
390 ret = -1;
391 goto out;
392 }
393 }
394
395 #ifdef CONFIG_FTRACE_STARTUP_TEST
396 if (type->selftest) {
397 struct tracer *saved_tracer = current_trace;
398 struct trace_array_cpu *data;
399 struct trace_array *tr = &global_trace;
400 int saved_ctrl = tr->ctrl;
401 int i;
402 /*
403 * Run a selftest on this tracer.
404 * Here we reset the trace buffer, and set the current
405 * tracer to be this tracer. The tracer can then run some
406 * internal tracing to verify that everything is in order.
407 * If we fail, we do not register this tracer.
408 */
409 for_each_possible_cpu(i) {
410 data = tr->data[i];
411 if (!head_page(data))
412 continue;
413 tracing_reset(data);
414 }
415 current_trace = type;
416 tr->ctrl = 0;
417 /* the test is responsible for initializing and enabling */
418 pr_info("Testing tracer %s: ", type->name);
419 ret = type->selftest(type, tr);
420 /* the test is responsible for resetting too */
421 current_trace = saved_tracer;
422 tr->ctrl = saved_ctrl;
423 if (ret) {
424 printk(KERN_CONT "FAILED!\n");
425 goto out;
426 }
427 /* Only reset on passing, to avoid touching corrupted buffers */
428 for_each_possible_cpu(i) {
429 data = tr->data[i];
430 if (!head_page(data))
431 continue;
432 tracing_reset(data);
433 }
434 printk(KERN_CONT "PASSED\n");
435 }
436 #endif
437
438 type->next = trace_types;
439 trace_types = type;
440 len = strlen(type->name);
441 if (len > max_tracer_type_len)
442 max_tracer_type_len = len;
443
444 out:
445 mutex_unlock(&trace_types_lock);
446
447 return ret;
448 }
449
450 void unregister_tracer(struct tracer *type)
451 {
452 struct tracer **t;
453 int len;
454
455 mutex_lock(&trace_types_lock);
456 for (t = &trace_types; *t; t = &(*t)->next) {
457 if (*t == type)
458 goto found;
459 }
460 pr_info("Trace %s not registered\n", type->name);
461 goto out;
462
463 found:
464 *t = (*t)->next;
465 if (strlen(type->name) != max_tracer_type_len)
466 goto out;
467
468 max_tracer_type_len = 0;
469 for (t = &trace_types; *t; t = &(*t)->next) {
470 len = strlen((*t)->name);
471 if (len > max_tracer_type_len)
472 max_tracer_type_len = len;
473 }
474 out:
475 mutex_unlock(&trace_types_lock);
476 }
477
478 void tracing_reset(struct trace_array_cpu *data)
479 {
480 data->trace_idx = 0;
481 data->trace_head = data->trace_tail = head_page(data);
482 data->trace_head_idx = 0;
483 data->trace_tail_idx = 0;
484 }
485
486 #define SAVED_CMDLINES 128
487 static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
488 static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
489 static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
490 static int cmdline_idx;
491 static DEFINE_SPINLOCK(trace_cmdline_lock);
492 atomic_t trace_record_cmdline_disabled;
493
494 static void trace_init_cmdlines(void)
495 {
496 memset(&map_pid_to_cmdline, -1, sizeof(map_pid_to_cmdline));
497 memset(&map_cmdline_to_pid, -1, sizeof(map_cmdline_to_pid));
498 cmdline_idx = 0;
499 }
500
501 void trace_stop_cmdline_recording(void);
502
503 static void trace_save_cmdline(struct task_struct *tsk)
504 {
505 unsigned map;
506 unsigned idx;
507
508 if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
509 return;
510
511 /*
512 * It's not the end of the world if we don't get
513 * the lock, but we also don't want to spin
514 * nor do we want to disable interrupts,
515 * so if we miss here, then better luck next time.
516 */
517 if (!spin_trylock(&trace_cmdline_lock))
518 return;
519
520 idx = map_pid_to_cmdline[tsk->pid];
521 if (idx >= SAVED_CMDLINES) {
522 idx = (cmdline_idx + 1) % SAVED_CMDLINES;
523
524 map = map_cmdline_to_pid[idx];
525 if (map <= PID_MAX_DEFAULT)
526 map_pid_to_cmdline[map] = (unsigned)-1;
527
528 map_pid_to_cmdline[tsk->pid] = idx;
529
530 cmdline_idx = idx;
531 }
532
533 memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
534
535 spin_unlock(&trace_cmdline_lock);
536 }
537
538 static char *trace_find_cmdline(int pid)
539 {
540 char *cmdline = "<...>";
541 unsigned map;
542
543 if (!pid)
544 return "<idle>";
545
546 if (pid > PID_MAX_DEFAULT)
547 goto out;
548
549 map = map_pid_to_cmdline[pid];
550 if (map >= SAVED_CMDLINES)
551 goto out;
552
553 cmdline = saved_cmdlines[map];
554
555 out:
556 return cmdline;
557 }
558
559 void tracing_record_cmdline(struct task_struct *tsk)
560 {
561 if (atomic_read(&trace_record_cmdline_disabled))
562 return;
563
564 trace_save_cmdline(tsk);
565 }
566
567 static inline struct list_head *
568 trace_next_list(struct trace_array_cpu *data, struct list_head *next)
569 {
570 /*
571 * Roundrobin - but skip the head (which is not a real page):
572 */
573 next = next->next;
574 if (unlikely(next == &data->trace_pages))
575 next = next->next;
576 BUG_ON(next == &data->trace_pages);
577
578 return next;
579 }
580
581 static inline void *
582 trace_next_page(struct trace_array_cpu *data, void *addr)
583 {
584 struct list_head *next;
585 struct page *page;
586
587 page = virt_to_page(addr);
588
589 next = trace_next_list(data, &page->lru);
590 page = list_entry(next, struct page, lru);
591
592 return page_address(page);
593 }
594
595 static inline struct trace_entry *
596 tracing_get_trace_entry(struct trace_array *tr, struct trace_array_cpu *data)
597 {
598 unsigned long idx, idx_next;
599 struct trace_entry *entry;
600
601 data->trace_idx++;
602 idx = data->trace_head_idx;
603 idx_next = idx + 1;
604
605 BUG_ON(idx * TRACE_ENTRY_SIZE >= PAGE_SIZE);
606
607 entry = data->trace_head + idx * TRACE_ENTRY_SIZE;
608
609 if (unlikely(idx_next >= ENTRIES_PER_PAGE)) {
610 data->trace_head = trace_next_page(data, data->trace_head);
611 idx_next = 0;
612 }
613
614 if (data->trace_head == data->trace_tail &&
615 idx_next == data->trace_tail_idx) {
616 /* overrun */
617 data->trace_tail_idx++;
618 if (data->trace_tail_idx >= ENTRIES_PER_PAGE) {
619 data->trace_tail =
620 trace_next_page(data, data->trace_tail);
621 data->trace_tail_idx = 0;
622 }
623 }
624
625 data->trace_head_idx = idx_next;
626
627 return entry;
628 }
629
630 static inline void
631 tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags)
632 {
633 struct task_struct *tsk = current;
634 unsigned long pc;
635
636 pc = preempt_count();
637
638 entry->preempt_count = pc & 0xff;
639 entry->pid = tsk->pid;
640 entry->t = ftrace_now(raw_smp_processor_id());
641 entry->flags = (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
642 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
643 ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
644 (need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
645 }
646
647 void
648 trace_function(struct trace_array *tr, struct trace_array_cpu *data,
649 unsigned long ip, unsigned long parent_ip, unsigned long flags)
650 {
651 struct trace_entry *entry;
652 unsigned long irq_flags;
653
654 spin_lock_irqsave(&data->lock, irq_flags);
655 entry = tracing_get_trace_entry(tr, data);
656 tracing_generic_entry_update(entry, flags);
657 entry->type = TRACE_FN;
658 entry->fn.ip = ip;
659 entry->fn.parent_ip = parent_ip;
660 spin_unlock_irqrestore(&data->lock, irq_flags);
661
662 trace_wake_up();
663 }
664
665 void
666 ftrace(struct trace_array *tr, struct trace_array_cpu *data,
667 unsigned long ip, unsigned long parent_ip, unsigned long flags)
668 {
669 if (likely(!atomic_read(&data->disabled)))
670 trace_function(tr, data, ip, parent_ip, flags);
671 }
672
673 void
674 __trace_special(void *__tr, void *__data,
675 unsigned long arg1, unsigned long arg2, unsigned long arg3)
676 {
677 struct trace_array_cpu *data = __data;
678 struct trace_array *tr = __tr;
679 struct trace_entry *entry;
680 unsigned long irq_flags;
681
682 spin_lock_irqsave(&data->lock, irq_flags);
683 entry = tracing_get_trace_entry(tr, data);
684 tracing_generic_entry_update(entry, 0);
685 entry->type = TRACE_SPECIAL;
686 entry->special.arg1 = arg1;
687 entry->special.arg2 = arg2;
688 entry->special.arg3 = arg3;
689 spin_unlock_irqrestore(&data->lock, irq_flags);
690
691 trace_wake_up();
692 }
693
694 void __trace_stack(struct trace_array *tr,
695 struct trace_array_cpu *data,
696 unsigned long flags,
697 int skip)
698 {
699 struct trace_entry *entry;
700 struct stack_trace trace;
701
702 if (!(trace_flags & TRACE_ITER_STACKTRACE))
703 return;
704
705 entry = tracing_get_trace_entry(tr, data);
706 tracing_generic_entry_update(entry, flags);
707 entry->type = TRACE_STACK;
708
709 memset(&entry->stack, 0, sizeof(entry->stack));
710
711 trace.nr_entries = 0;
712 trace.max_entries = FTRACE_STACK_ENTRIES;
713 trace.skip = skip;
714 trace.entries = entry->stack.caller;
715
716 save_stack_trace(&trace);
717 }
718
719 void
720 tracing_sched_switch_trace(struct trace_array *tr,
721 struct trace_array_cpu *data,
722 struct task_struct *prev,
723 struct task_struct *next,
724 unsigned long flags)
725 {
726 struct trace_entry *entry;
727 unsigned long irq_flags;
728
729 spin_lock_irqsave(&data->lock, irq_flags);
730 entry = tracing_get_trace_entry(tr, data);
731 tracing_generic_entry_update(entry, flags);
732 entry->type = TRACE_CTX;
733 entry->ctx.prev_pid = prev->pid;
734 entry->ctx.prev_prio = prev->prio;
735 entry->ctx.prev_state = prev->state;
736 entry->ctx.next_pid = next->pid;
737 entry->ctx.next_prio = next->prio;
738 __trace_stack(tr, data, flags, 4);
739 spin_unlock_irqrestore(&data->lock, irq_flags);
740 }
741
742 void
743 tracing_sched_wakeup_trace(struct trace_array *tr,
744 struct trace_array_cpu *data,
745 struct task_struct *wakee,
746 struct task_struct *curr,
747 unsigned long flags)
748 {
749 struct trace_entry *entry;
750 unsigned long irq_flags;
751
752 spin_lock_irqsave(&data->lock, irq_flags);
753 entry = tracing_get_trace_entry(tr, data);
754 tracing_generic_entry_update(entry, flags);
755 entry->type = TRACE_WAKE;
756 entry->ctx.prev_pid = curr->pid;
757 entry->ctx.prev_prio = curr->prio;
758 entry->ctx.prev_state = curr->state;
759 entry->ctx.next_pid = wakee->pid;
760 entry->ctx.next_prio = wakee->prio;
761 __trace_stack(tr, data, flags, 5);
762 spin_unlock_irqrestore(&data->lock, irq_flags);
763
764 trace_wake_up();
765 }
766
767 #ifdef CONFIG_FTRACE
768 static void
769 function_trace_call(unsigned long ip, unsigned long parent_ip)
770 {
771 struct trace_array *tr = &global_trace;
772 struct trace_array_cpu *data;
773 unsigned long flags;
774 long disabled;
775 int cpu;
776
777 if (unlikely(!tracer_enabled))
778 return;
779
780 local_irq_save(flags);
781 cpu = raw_smp_processor_id();
782 data = tr->data[cpu];
783 disabled = atomic_inc_return(&data->disabled);
784
785 if (likely(disabled == 1))
786 trace_function(tr, data, ip, parent_ip, flags);
787
788 atomic_dec(&data->disabled);
789 local_irq_restore(flags);
790 }
791
792 static struct ftrace_ops trace_ops __read_mostly =
793 {
794 .func = function_trace_call,
795 };
796
797 void tracing_start_function_trace(void)
798 {
799 register_ftrace_function(&trace_ops);
800 }
801
802 void tracing_stop_function_trace(void)
803 {
804 unregister_ftrace_function(&trace_ops);
805 }
806 #endif
807
808 enum trace_file_type {
809 TRACE_FILE_LAT_FMT = 1,
810 };
811
812 static struct trace_entry *
813 trace_entry_idx(struct trace_array *tr, struct trace_array_cpu *data,
814 struct trace_iterator *iter, int cpu)
815 {
816 struct page *page;
817 struct trace_entry *array;
818
819 if (iter->next_idx[cpu] >= tr->entries ||
820 iter->next_idx[cpu] >= data->trace_idx ||
821 (data->trace_head == data->trace_tail &&
822 data->trace_head_idx == data->trace_tail_idx))
823 return NULL;
824
825 if (!iter->next_page[cpu]) {
826 /* Initialize the iterator for this cpu trace buffer */
827 WARN_ON(!data->trace_tail);
828 page = virt_to_page(data->trace_tail);
829 iter->next_page[cpu] = &page->lru;
830 iter->next_page_idx[cpu] = data->trace_tail_idx;
831 }
832
833 page = list_entry(iter->next_page[cpu], struct page, lru);
834 BUG_ON(&data->trace_pages == &page->lru);
835
836 array = page_address(page);
837
838 WARN_ON(iter->next_page_idx[cpu] >= ENTRIES_PER_PAGE);
839 return &array[iter->next_page_idx[cpu]];
840 }
841
842 static struct trace_entry *
843 find_next_entry(struct trace_iterator *iter, int *ent_cpu)
844 {
845 struct trace_array *tr = iter->tr;
846 struct trace_entry *ent, *next = NULL;
847 int next_cpu = -1;
848 int cpu;
849
850 for_each_possible_cpu(cpu) {
851 if (!head_page(tr->data[cpu]))
852 continue;
853 ent = trace_entry_idx(tr, tr->data[cpu], iter, cpu);
854 /*
855 * Pick the entry with the smallest timestamp:
856 */
857 if (ent && (!next || ent->t < next->t)) {
858 next = ent;
859 next_cpu = cpu;
860 }
861 }
862
863 if (ent_cpu)
864 *ent_cpu = next_cpu;
865
866 return next;
867 }
868
869 static void trace_iterator_increment(struct trace_iterator *iter)
870 {
871 iter->idx++;
872 iter->next_idx[iter->cpu]++;
873 iter->next_page_idx[iter->cpu]++;
874
875 if (iter->next_page_idx[iter->cpu] >= ENTRIES_PER_PAGE) {
876 struct trace_array_cpu *data = iter->tr->data[iter->cpu];
877
878 iter->next_page_idx[iter->cpu] = 0;
879 iter->next_page[iter->cpu] =
880 trace_next_list(data, iter->next_page[iter->cpu]);
881 }
882 }
883
884 static void trace_consume(struct trace_iterator *iter)
885 {
886 struct trace_array_cpu *data = iter->tr->data[iter->cpu];
887
888 data->trace_tail_idx++;
889 if (data->trace_tail_idx >= ENTRIES_PER_PAGE) {
890 data->trace_tail = trace_next_page(data, data->trace_tail);
891 data->trace_tail_idx = 0;
892 }
893
894 /* Check if we empty it, then reset the index */
895 if (data->trace_head == data->trace_tail &&
896 data->trace_head_idx == data->trace_tail_idx)
897 data->trace_idx = 0;
898 }
899
900 static void *find_next_entry_inc(struct trace_iterator *iter)
901 {
902 struct trace_entry *next;
903 int next_cpu = -1;
904
905 next = find_next_entry(iter, &next_cpu);
906
907 iter->prev_ent = iter->ent;
908 iter->prev_cpu = iter->cpu;
909
910 iter->ent = next;
911 iter->cpu = next_cpu;
912
913 if (next)
914 trace_iterator_increment(iter);
915
916 return next ? iter : NULL;
917 }
918
919 static void *s_next(struct seq_file *m, void *v, loff_t *pos)
920 {
921 struct trace_iterator *iter = m->private;
922 void *last_ent = iter->ent;
923 int i = (int)*pos;
924 void *ent;
925
926 (*pos)++;
927
928 /* can't go backwards */
929 if (iter->idx > i)
930 return NULL;
931
932 if (iter->idx < 0)
933 ent = find_next_entry_inc(iter);
934 else
935 ent = iter;
936
937 while (ent && iter->idx < i)
938 ent = find_next_entry_inc(iter);
939
940 iter->pos = *pos;
941
942 if (last_ent && !ent)
943 seq_puts(m, "\n\nvim:ft=help\n");
944
945 return ent;
946 }
947
948 static void *s_start(struct seq_file *m, loff_t *pos)
949 {
950 struct trace_iterator *iter = m->private;
951 void *p = NULL;
952 loff_t l = 0;
953 int i;
954
955 mutex_lock(&trace_types_lock);
956
957 if (!current_trace || current_trace != iter->trace)
958 return NULL;
959
960 atomic_inc(&trace_record_cmdline_disabled);
961
962 /* let the tracer grab locks here if needed */
963 if (current_trace->start)
964 current_trace->start(iter);
965
966 if (*pos != iter->pos) {
967 iter->ent = NULL;
968 iter->cpu = 0;
969 iter->idx = -1;
970 iter->prev_ent = NULL;
971 iter->prev_cpu = -1;
972
973 for_each_possible_cpu(i) {
974 iter->next_idx[i] = 0;
975 iter->next_page[i] = NULL;
976 }
977
978 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
979 ;
980
981 } else {
982 l = *pos - 1;
983 p = s_next(m, p, &l);
984 }
985
986 return p;
987 }
988
989 static void s_stop(struct seq_file *m, void *p)
990 {
991 struct trace_iterator *iter = m->private;
992
993 atomic_dec(&trace_record_cmdline_disabled);
994
995 /* let the tracer release locks here if needed */
996 if (current_trace && current_trace == iter->trace && iter->trace->stop)
997 iter->trace->stop(iter);
998
999 mutex_unlock(&trace_types_lock);
1000 }
1001
1002 static int
1003 seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
1004 {
1005 #ifdef CONFIG_KALLSYMS
1006 char str[KSYM_SYMBOL_LEN];
1007
1008 kallsyms_lookup(address, NULL, NULL, NULL, str);
1009
1010 return trace_seq_printf(s, fmt, str);
1011 #endif
1012 return 1;
1013 }
1014
1015 static int
1016 seq_print_sym_offset(struct trace_seq *s, const char *fmt,
1017 unsigned long address)
1018 {
1019 #ifdef CONFIG_KALLSYMS
1020 char str[KSYM_SYMBOL_LEN];
1021
1022 sprint_symbol(str, address);
1023 return trace_seq_printf(s, fmt, str);
1024 #endif
1025 return 1;
1026 }
1027
1028 #ifndef CONFIG_64BIT
1029 # define IP_FMT "%08lx"
1030 #else
1031 # define IP_FMT "%016lx"
1032 #endif
1033
1034 static int
1035 seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
1036 {
1037 int ret;
1038
1039 if (!ip)
1040 return trace_seq_printf(s, "0");
1041
1042 if (sym_flags & TRACE_ITER_SYM_OFFSET)
1043 ret = seq_print_sym_offset(s, "%s", ip);
1044 else
1045 ret = seq_print_sym_short(s, "%s", ip);
1046
1047 if (!ret)
1048 return 0;
1049
1050 if (sym_flags & TRACE_ITER_SYM_ADDR)
1051 ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
1052 return ret;
1053 }
1054
1055 static void print_lat_help_header(struct seq_file *m)
1056 {
1057 seq_puts(m, "# _------=> CPU# \n");
1058 seq_puts(m, "# / _-----=> irqs-off \n");
1059 seq_puts(m, "# | / _----=> need-resched \n");
1060 seq_puts(m, "# || / _---=> hardirq/softirq \n");
1061 seq_puts(m, "# ||| / _--=> preempt-depth \n");
1062 seq_puts(m, "# |||| / \n");
1063 seq_puts(m, "# ||||| delay \n");
1064 seq_puts(m, "# cmd pid ||||| time | caller \n");
1065 seq_puts(m, "# \\ / ||||| \\ | / \n");
1066 }
1067
1068 static void print_func_help_header(struct seq_file *m)
1069 {
1070 seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1071 seq_puts(m, "# | | | | |\n");
1072 }
1073
1074
1075 static void
1076 print_trace_header(struct seq_file *m, struct trace_iterator *iter)
1077 {
1078 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1079 struct trace_array *tr = iter->tr;
1080 struct trace_array_cpu *data = tr->data[tr->cpu];
1081 struct tracer *type = current_trace;
1082 unsigned long total = 0;
1083 unsigned long entries = 0;
1084 int cpu;
1085 const char *name = "preemption";
1086
1087 if (type)
1088 name = type->name;
1089
1090 for_each_possible_cpu(cpu) {
1091 if (head_page(tr->data[cpu])) {
1092 total += tr->data[cpu]->trace_idx;
1093 if (tr->data[cpu]->trace_idx > tr->entries)
1094 entries += tr->entries;
1095 else
1096 entries += tr->data[cpu]->trace_idx;
1097 }
1098 }
1099
1100 seq_printf(m, "%s latency trace v1.1.5 on %s\n",
1101 name, UTS_RELEASE);
1102 seq_puts(m, "-----------------------------------"
1103 "---------------------------------\n");
1104 seq_printf(m, " latency: %lu us, #%lu/%lu, CPU#%d |"
1105 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1106 nsecs_to_usecs(data->saved_latency),
1107 entries,
1108 total,
1109 tr->cpu,
1110 #if defined(CONFIG_PREEMPT_NONE)
1111 "server",
1112 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1113 "desktop",
1114 #elif defined(CONFIG_PREEMPT_DESKTOP)
1115 "preempt",
1116 #else
1117 "unknown",
1118 #endif
1119 /* These are reserved for later use */
1120 0, 0, 0, 0);
1121 #ifdef CONFIG_SMP
1122 seq_printf(m, " #P:%d)\n", num_online_cpus());
1123 #else
1124 seq_puts(m, ")\n");
1125 #endif
1126 seq_puts(m, " -----------------\n");
1127 seq_printf(m, " | task: %.16s-%d "
1128 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1129 data->comm, data->pid, data->uid, data->nice,
1130 data->policy, data->rt_priority);
1131 seq_puts(m, " -----------------\n");
1132
1133 if (data->critical_start) {
1134 seq_puts(m, " => started at: ");
1135 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
1136 trace_print_seq(m, &iter->seq);
1137 seq_puts(m, "\n => ended at: ");
1138 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
1139 trace_print_seq(m, &iter->seq);
1140 seq_puts(m, "\n");
1141 }
1142
1143 seq_puts(m, "\n");
1144 }
1145
1146 static void
1147 lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
1148 {
1149 int hardirq, softirq;
1150 char *comm;
1151
1152 comm = trace_find_cmdline(entry->pid);
1153
1154 trace_seq_printf(s, "%8.8s-%-5d ", comm, entry->pid);
1155 trace_seq_printf(s, "%d", cpu);
1156 trace_seq_printf(s, "%c%c",
1157 (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' : '.',
1158 ((entry->flags & TRACE_FLAG_NEED_RESCHED) ? 'N' : '.'));
1159
1160 hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
1161 softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
1162 if (hardirq && softirq)
1163 trace_seq_putc(s, 'H');
1164 else {
1165 if (hardirq)
1166 trace_seq_putc(s, 'h');
1167 else {
1168 if (softirq)
1169 trace_seq_putc(s, 's');
1170 else
1171 trace_seq_putc(s, '.');
1172 }
1173 }
1174
1175 if (entry->preempt_count)
1176 trace_seq_printf(s, "%x", entry->preempt_count);
1177 else
1178 trace_seq_puts(s, ".");
1179 }
1180
1181 unsigned long preempt_mark_thresh = 100;
1182
1183 static void
1184 lat_print_timestamp(struct trace_seq *s, unsigned long long abs_usecs,
1185 unsigned long rel_usecs)
1186 {
1187 trace_seq_printf(s, " %4lldus", abs_usecs);
1188 if (rel_usecs > preempt_mark_thresh)
1189 trace_seq_puts(s, "!: ");
1190 else if (rel_usecs > 1)
1191 trace_seq_puts(s, "+: ");
1192 else
1193 trace_seq_puts(s, " : ");
1194 }
1195
1196 static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
1197
1198 static int
1199 print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
1200 {
1201 struct trace_seq *s = &iter->seq;
1202 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1203 struct trace_entry *next_entry = find_next_entry(iter, NULL);
1204 unsigned long verbose = (trace_flags & TRACE_ITER_VERBOSE);
1205 struct trace_entry *entry = iter->ent;
1206 unsigned long abs_usecs;
1207 unsigned long rel_usecs;
1208 char *comm;
1209 int S;
1210 int i;
1211
1212 if (!next_entry)
1213 next_entry = entry;
1214 rel_usecs = ns2usecs(next_entry->t - entry->t);
1215 abs_usecs = ns2usecs(entry->t - iter->tr->time_start);
1216
1217 if (verbose) {
1218 comm = trace_find_cmdline(entry->pid);
1219 trace_seq_printf(s, "%16s %5d %d %d %08x %08x [%08lx]"
1220 " %ld.%03ldms (+%ld.%03ldms): ",
1221 comm,
1222 entry->pid, cpu, entry->flags,
1223 entry->preempt_count, trace_idx,
1224 ns2usecs(entry->t),
1225 abs_usecs/1000,
1226 abs_usecs % 1000, rel_usecs/1000,
1227 rel_usecs % 1000);
1228 } else {
1229 if (entry->type != TRACE_STACK) {
1230 lat_print_generic(s, entry, cpu);
1231 lat_print_timestamp(s, abs_usecs, rel_usecs);
1232 }
1233 }
1234 switch (entry->type) {
1235 case TRACE_FN:
1236 seq_print_ip_sym(s, entry->fn.ip, sym_flags);
1237 trace_seq_puts(s, " (");
1238 seq_print_ip_sym(s, entry->fn.parent_ip, sym_flags);
1239 trace_seq_puts(s, ")\n");
1240 break;
1241 case TRACE_CTX:
1242 case TRACE_WAKE:
1243 S = entry->ctx.prev_state < sizeof(state_to_char) ?
1244 state_to_char[entry->ctx.prev_state] : 'X';
1245 comm = trace_find_cmdline(entry->ctx.next_pid);
1246 trace_seq_printf(s, " %5d:%3d:%c %s %5d:%3d %s\n",
1247 entry->ctx.prev_pid,
1248 entry->ctx.prev_prio,
1249 S, entry->type == TRACE_CTX ? "==>" : " +",
1250 entry->ctx.next_pid,
1251 entry->ctx.next_prio,
1252 comm);
1253 break;
1254 case TRACE_SPECIAL:
1255 trace_seq_printf(s, " %ld %ld %ld\n",
1256 entry->special.arg1,
1257 entry->special.arg2,
1258 entry->special.arg3);
1259 break;
1260 case TRACE_STACK:
1261 for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
1262 if (i)
1263 trace_seq_puts(s, " <= ");
1264 seq_print_ip_sym(s, entry->stack.caller[i], sym_flags);
1265 }
1266 trace_seq_puts(s, "\n");
1267 break;
1268 default:
1269 trace_seq_printf(s, "Unknown type %d\n", entry->type);
1270 }
1271 return 1;
1272 }
1273
1274 static int print_trace_fmt(struct trace_iterator *iter)
1275 {
1276 struct trace_seq *s = &iter->seq;
1277 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1278 struct trace_entry *entry;
1279 unsigned long usec_rem;
1280 unsigned long long t;
1281 unsigned long secs;
1282 char *comm;
1283 int ret;
1284 int S;
1285 int i;
1286
1287 entry = iter->ent;
1288
1289 comm = trace_find_cmdline(iter->ent->pid);
1290
1291 t = ns2usecs(entry->t);
1292 usec_rem = do_div(t, 1000000ULL);
1293 secs = (unsigned long)t;
1294
1295 if (entry->type != TRACE_STACK) {
1296 ret = trace_seq_printf(s, "%16s-%-5d ", comm, entry->pid);
1297 if (!ret)
1298 return 0;
1299 ret = trace_seq_printf(s, "[%02d] ", iter->cpu);
1300 if (!ret)
1301 return 0;
1302 ret = trace_seq_printf(s, "%5lu.%06lu: ", secs, usec_rem);
1303 if (!ret)
1304 return 0;
1305 }
1306
1307 switch (entry->type) {
1308 case TRACE_FN:
1309 ret = seq_print_ip_sym(s, entry->fn.ip, sym_flags);
1310 if (!ret)
1311 return 0;
1312 if ((sym_flags & TRACE_ITER_PRINT_PARENT) &&
1313 entry->fn.parent_ip) {
1314 ret = trace_seq_printf(s, " <-");
1315 if (!ret)
1316 return 0;
1317 ret = seq_print_ip_sym(s, entry->fn.parent_ip,
1318 sym_flags);
1319 if (!ret)
1320 return 0;
1321 }
1322 ret = trace_seq_printf(s, "\n");
1323 if (!ret)
1324 return 0;
1325 break;
1326 case TRACE_CTX:
1327 case TRACE_WAKE:
1328 S = entry->ctx.prev_state < sizeof(state_to_char) ?
1329 state_to_char[entry->ctx.prev_state] : 'X';
1330 ret = trace_seq_printf(s, " %5d:%3d:%c %s %5d:%3d\n",
1331 entry->ctx.prev_pid,
1332 entry->ctx.prev_prio,
1333 S,
1334 entry->type == TRACE_CTX ? "==>" : " +",
1335 entry->ctx.next_pid,
1336 entry->ctx.next_prio);
1337 if (!ret)
1338 return 0;
1339 break;
1340 case TRACE_SPECIAL:
1341 ret = trace_seq_printf(s, " %ld %ld %ld\n",
1342 entry->special.arg1,
1343 entry->special.arg2,
1344 entry->special.arg3);
1345 if (!ret)
1346 return 0;
1347 break;
1348 case TRACE_STACK:
1349 for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
1350 if (i) {
1351 ret = trace_seq_puts(s, " <= ");
1352 if (!ret)
1353 return 0;
1354 }
1355 ret = seq_print_ip_sym(s, entry->stack.caller[i],
1356 sym_flags);
1357 if (!ret)
1358 return 0;
1359 }
1360 ret = trace_seq_puts(s, "\n");
1361 if (!ret)
1362 return 0;
1363 break;
1364 }
1365 return 1;
1366 }
1367
1368 static int print_raw_fmt(struct trace_iterator *iter)
1369 {
1370 struct trace_seq *s = &iter->seq;
1371 struct trace_entry *entry;
1372 int ret;
1373 int S;
1374
1375 entry = iter->ent;
1376
1377 ret = trace_seq_printf(s, "%d %d %llu ",
1378 entry->pid, iter->cpu, entry->t);
1379 if (!ret)
1380 return 0;
1381
1382 switch (entry->type) {
1383 case TRACE_FN:
1384 ret = trace_seq_printf(s, "%x %x\n",
1385 entry->fn.ip, entry->fn.parent_ip);
1386 if (!ret)
1387 return 0;
1388 break;
1389 case TRACE_CTX:
1390 case TRACE_WAKE:
1391 S = entry->ctx.prev_state < sizeof(state_to_char) ?
1392 state_to_char[entry->ctx.prev_state] : 'X';
1393 if (entry->type == TRACE_WAKE)
1394 S = '+';
1395 ret = trace_seq_printf(s, "%d %d %c %d %d\n",
1396 entry->ctx.prev_pid,
1397 entry->ctx.prev_prio,
1398 S,
1399 entry->ctx.next_pid,
1400 entry->ctx.next_prio);
1401 if (!ret)
1402 return 0;
1403 break;
1404 case TRACE_SPECIAL:
1405 case TRACE_STACK:
1406 ret = trace_seq_printf(s, " %ld %ld %ld\n",
1407 entry->special.arg1,
1408 entry->special.arg2,
1409 entry->special.arg3);
1410 if (!ret)
1411 return 0;
1412 break;
1413 }
1414 return 1;
1415 }
1416
1417 #define SEQ_PUT_FIELD_RET(s, x) \
1418 do { \
1419 if (!trace_seq_putmem(s, &(x), sizeof(x))) \
1420 return 0; \
1421 } while (0)
1422
1423 #define SEQ_PUT_HEX_FIELD_RET(s, x) \
1424 do { \
1425 if (!trace_seq_putmem_hex(s, &(x), sizeof(x))) \
1426 return 0; \
1427 } while (0)
1428
1429 static int print_hex_fmt(struct trace_iterator *iter)
1430 {
1431 struct trace_seq *s = &iter->seq;
1432 unsigned char newline = '\n';
1433 struct trace_entry *entry;
1434 int S;
1435
1436 entry = iter->ent;
1437
1438 SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
1439 SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
1440 SEQ_PUT_HEX_FIELD_RET(s, entry->t);
1441
1442 switch (entry->type) {
1443 case TRACE_FN:
1444 SEQ_PUT_HEX_FIELD_RET(s, entry->fn.ip);
1445 SEQ_PUT_HEX_FIELD_RET(s, entry->fn.parent_ip);
1446 break;
1447 case TRACE_CTX:
1448 case TRACE_WAKE:
1449 S = entry->ctx.prev_state < sizeof(state_to_char) ?
1450 state_to_char[entry->ctx.prev_state] : 'X';
1451 if (entry->type == TRACE_WAKE)
1452 S = '+';
1453 SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.prev_pid);
1454 SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.prev_prio);
1455 SEQ_PUT_HEX_FIELD_RET(s, S);
1456 SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.next_pid);
1457 SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.next_prio);
1458 SEQ_PUT_HEX_FIELD_RET(s, entry->fn.parent_ip);
1459 break;
1460 case TRACE_SPECIAL:
1461 case TRACE_STACK:
1462 SEQ_PUT_HEX_FIELD_RET(s, entry->special.arg1);
1463 SEQ_PUT_HEX_FIELD_RET(s, entry->special.arg2);
1464 SEQ_PUT_HEX_FIELD_RET(s, entry->special.arg3);
1465 break;
1466 }
1467 SEQ_PUT_FIELD_RET(s, newline);
1468
1469 return 1;
1470 }
1471
1472 static int print_bin_fmt(struct trace_iterator *iter)
1473 {
1474 struct trace_seq *s = &iter->seq;
1475 struct trace_entry *entry;
1476
1477 entry = iter->ent;
1478
1479 SEQ_PUT_FIELD_RET(s, entry->pid);
1480 SEQ_PUT_FIELD_RET(s, entry->cpu);
1481 SEQ_PUT_FIELD_RET(s, entry->t);
1482
1483 switch (entry->type) {
1484 case TRACE_FN:
1485 SEQ_PUT_FIELD_RET(s, entry->fn.ip);
1486 SEQ_PUT_FIELD_RET(s, entry->fn.parent_ip);
1487 break;
1488 case TRACE_CTX:
1489 SEQ_PUT_FIELD_RET(s, entry->ctx.prev_pid);
1490 SEQ_PUT_FIELD_RET(s, entry->ctx.prev_prio);
1491 SEQ_PUT_FIELD_RET(s, entry->ctx.prev_state);
1492 SEQ_PUT_FIELD_RET(s, entry->ctx.next_pid);
1493 SEQ_PUT_FIELD_RET(s, entry->ctx.next_prio);
1494 break;
1495 case TRACE_SPECIAL:
1496 case TRACE_STACK:
1497 SEQ_PUT_FIELD_RET(s, entry->special.arg1);
1498 SEQ_PUT_FIELD_RET(s, entry->special.arg2);
1499 SEQ_PUT_FIELD_RET(s, entry->special.arg3);
1500 break;
1501 }
1502 return 1;
1503 }
1504
1505 static int trace_empty(struct trace_iterator *iter)
1506 {
1507 struct trace_array_cpu *data;
1508 int cpu;
1509
1510 for_each_possible_cpu(cpu) {
1511 data = iter->tr->data[cpu];
1512
1513 if (head_page(data) && data->trace_idx &&
1514 (data->trace_tail != data->trace_head ||
1515 data->trace_tail_idx != data->trace_head_idx))
1516 return 0;
1517 }
1518 return 1;
1519 }
1520
1521 static int print_trace_line(struct trace_iterator *iter)
1522 {
1523 if (trace_flags & TRACE_ITER_BIN)
1524 return print_bin_fmt(iter);
1525
1526 if (trace_flags & TRACE_ITER_HEX)
1527 return print_hex_fmt(iter);
1528
1529 if (trace_flags & TRACE_ITER_RAW)
1530 return print_raw_fmt(iter);
1531
1532 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
1533 return print_lat_fmt(iter, iter->idx, iter->cpu);
1534
1535 return print_trace_fmt(iter);
1536 }
1537
1538 static int s_show(struct seq_file *m, void *v)
1539 {
1540 struct trace_iterator *iter = v;
1541
1542 if (iter->ent == NULL) {
1543 if (iter->tr) {
1544 seq_printf(m, "# tracer: %s\n", iter->trace->name);
1545 seq_puts(m, "#\n");
1546 }
1547 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
1548 /* print nothing if the buffers are empty */
1549 if (trace_empty(iter))
1550 return 0;
1551 print_trace_header(m, iter);
1552 if (!(trace_flags & TRACE_ITER_VERBOSE))
1553 print_lat_help_header(m);
1554 } else {
1555 if (!(trace_flags & TRACE_ITER_VERBOSE))
1556 print_func_help_header(m);
1557 }
1558 } else {
1559 print_trace_line(iter);
1560 trace_print_seq(m, &iter->seq);
1561 }
1562
1563 return 0;
1564 }
1565
1566 static struct seq_operations tracer_seq_ops = {
1567 .start = s_start,
1568 .next = s_next,
1569 .stop = s_stop,
1570 .show = s_show,
1571 };
1572
1573 static struct trace_iterator *
1574 __tracing_open(struct inode *inode, struct file *file, int *ret)
1575 {
1576 struct trace_iterator *iter;
1577
1578 if (tracing_disabled) {
1579 *ret = -ENODEV;
1580 return NULL;
1581 }
1582
1583 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1584 if (!iter) {
1585 *ret = -ENOMEM;
1586 goto out;
1587 }
1588
1589 mutex_lock(&trace_types_lock);
1590 if (current_trace && current_trace->print_max)
1591 iter->tr = &max_tr;
1592 else
1593 iter->tr = inode->i_private;
1594 iter->trace = current_trace;
1595 iter->pos = -1;
1596
1597 /* TODO stop tracer */
1598 *ret = seq_open(file, &tracer_seq_ops);
1599 if (!*ret) {
1600 struct seq_file *m = file->private_data;
1601 m->private = iter;
1602
1603 /* stop the trace while dumping */
1604 if (iter->tr->ctrl)
1605 tracer_enabled = 0;
1606
1607 if (iter->trace && iter->trace->open)
1608 iter->trace->open(iter);
1609 } else {
1610 kfree(iter);
1611 iter = NULL;
1612 }
1613 mutex_unlock(&trace_types_lock);
1614
1615 out:
1616 return iter;
1617 }
1618
1619 int tracing_open_generic(struct inode *inode, struct file *filp)
1620 {
1621 if (tracing_disabled)
1622 return -ENODEV;
1623
1624 filp->private_data = inode->i_private;
1625 return 0;
1626 }
1627
1628 int tracing_release(struct inode *inode, struct file *file)
1629 {
1630 struct seq_file *m = (struct seq_file *)file->private_data;
1631 struct trace_iterator *iter = m->private;
1632
1633 mutex_lock(&trace_types_lock);
1634 if (iter->trace && iter->trace->close)
1635 iter->trace->close(iter);
1636
1637 /* reenable tracing if it was previously enabled */
1638 if (iter->tr->ctrl)
1639 tracer_enabled = 1;
1640 mutex_unlock(&trace_types_lock);
1641
1642 seq_release(inode, file);
1643 kfree(iter);
1644 return 0;
1645 }
1646
1647 static int tracing_open(struct inode *inode, struct file *file)
1648 {
1649 int ret;
1650
1651 __tracing_open(inode, file, &ret);
1652
1653 return ret;
1654 }
1655
1656 static int tracing_lt_open(struct inode *inode, struct file *file)
1657 {
1658 struct trace_iterator *iter;
1659 int ret;
1660
1661 iter = __tracing_open(inode, file, &ret);
1662
1663 if (!ret)
1664 iter->iter_flags |= TRACE_FILE_LAT_FMT;
1665
1666 return ret;
1667 }
1668
1669
1670 static void *
1671 t_next(struct seq_file *m, void *v, loff_t *pos)
1672 {
1673 struct tracer *t = m->private;
1674
1675 (*pos)++;
1676
1677 if (t)
1678 t = t->next;
1679
1680 m->private = t;
1681
1682 return t;
1683 }
1684
1685 static void *t_start(struct seq_file *m, loff_t *pos)
1686 {
1687 struct tracer *t = m->private;
1688 loff_t l = 0;
1689
1690 mutex_lock(&trace_types_lock);
1691 for (; t && l < *pos; t = t_next(m, t, &l))
1692 ;
1693
1694 return t;
1695 }
1696
1697 static void t_stop(struct seq_file *m, void *p)
1698 {
1699 mutex_unlock(&trace_types_lock);
1700 }
1701
1702 static int t_show(struct seq_file *m, void *v)
1703 {
1704 struct tracer *t = v;
1705
1706 if (!t)
1707 return 0;
1708
1709 seq_printf(m, "%s", t->name);
1710 if (t->next)
1711 seq_putc(m, ' ');
1712 else
1713 seq_putc(m, '\n');
1714
1715 return 0;
1716 }
1717
1718 static struct seq_operations show_traces_seq_ops = {
1719 .start = t_start,
1720 .next = t_next,
1721 .stop = t_stop,
1722 .show = t_show,
1723 };
1724
1725 static int show_traces_open(struct inode *inode, struct file *file)
1726 {
1727 int ret;
1728
1729 if (tracing_disabled)
1730 return -ENODEV;
1731
1732 ret = seq_open(file, &show_traces_seq_ops);
1733 if (!ret) {
1734 struct seq_file *m = file->private_data;
1735 m->private = trace_types;
1736 }
1737
1738 return ret;
1739 }
1740
1741 static struct file_operations tracing_fops = {
1742 .open = tracing_open,
1743 .read = seq_read,
1744 .llseek = seq_lseek,
1745 .release = tracing_release,
1746 };
1747
1748 static struct file_operations tracing_lt_fops = {
1749 .open = tracing_lt_open,
1750 .read = seq_read,
1751 .llseek = seq_lseek,
1752 .release = tracing_release,
1753 };
1754
1755 static struct file_operations show_traces_fops = {
1756 .open = show_traces_open,
1757 .read = seq_read,
1758 .release = seq_release,
1759 };
1760
1761 static ssize_t
1762 tracing_iter_ctrl_read(struct file *filp, char __user *ubuf,
1763 size_t cnt, loff_t *ppos)
1764 {
1765 char *buf;
1766 int r = 0;
1767 int len = 0;
1768 int i;
1769
1770 /* calulate max size */
1771 for (i = 0; trace_options[i]; i++) {
1772 len += strlen(trace_options[i]);
1773 len += 3; /* "no" and space */
1774 }
1775
1776 /* +2 for \n and \0 */
1777 buf = kmalloc(len + 2, GFP_KERNEL);
1778 if (!buf)
1779 return -ENOMEM;
1780
1781 for (i = 0; trace_options[i]; i++) {
1782 if (trace_flags & (1 << i))
1783 r += sprintf(buf + r, "%s ", trace_options[i]);
1784 else
1785 r += sprintf(buf + r, "no%s ", trace_options[i]);
1786 }
1787
1788 r += sprintf(buf + r, "\n");
1789 WARN_ON(r >= len + 2);
1790
1791 r = simple_read_from_buffer(ubuf, cnt, ppos,
1792 buf, r);
1793
1794 kfree(buf);
1795
1796 return r;
1797 }
1798
1799 static ssize_t
1800 tracing_iter_ctrl_write(struct file *filp, const char __user *ubuf,
1801 size_t cnt, loff_t *ppos)
1802 {
1803 char buf[64];
1804 char *cmp = buf;
1805 int neg = 0;
1806 int i;
1807
1808 if (cnt > 63)
1809 cnt = 63;
1810
1811 if (copy_from_user(&buf, ubuf, cnt))
1812 return -EFAULT;
1813
1814 buf[cnt] = 0;
1815
1816 if (strncmp(buf, "no", 2) == 0) {
1817 neg = 1;
1818 cmp += 2;
1819 }
1820
1821 for (i = 0; trace_options[i]; i++) {
1822 int len = strlen(trace_options[i]);
1823
1824 if (strncmp(cmp, trace_options[i], len) == 0) {
1825 if (neg)
1826 trace_flags &= ~(1 << i);
1827 else
1828 trace_flags |= (1 << i);
1829 break;
1830 }
1831 }
1832
1833 filp->f_pos += cnt;
1834
1835 return cnt;
1836 }
1837
1838 static struct file_operations tracing_iter_fops = {
1839 .open = tracing_open_generic,
1840 .read = tracing_iter_ctrl_read,
1841 .write = tracing_iter_ctrl_write,
1842 };
1843
1844 static const char readme_msg[] =
1845 "tracing mini-HOWTO:\n\n"
1846 "# mkdir /debug\n"
1847 "# mount -t debugfs nodev /debug\n\n"
1848 "# cat /debug/tracing/available_tracers\n"
1849 "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
1850 "# cat /debug/tracing/current_tracer\n"
1851 "none\n"
1852 "# echo sched_switch > /debug/tracing/current_tracer\n"
1853 "# cat /debug/tracing/current_tracer\n"
1854 "sched_switch\n"
1855 "# cat /debug/tracing/iter_ctrl\n"
1856 "noprint-parent nosym-offset nosym-addr noverbose\n"
1857 "# echo print-parent > /debug/tracing/iter_ctrl\n"
1858 "# echo 1 > /debug/tracing/tracing_enabled\n"
1859 "# cat /debug/tracing/trace > /tmp/trace.txt\n"
1860 "echo 0 > /debug/tracing/tracing_enabled\n"
1861 ;
1862
1863 static ssize_t
1864 tracing_readme_read(struct file *filp, char __user *ubuf,
1865 size_t cnt, loff_t *ppos)
1866 {
1867 return simple_read_from_buffer(ubuf, cnt, ppos,
1868 readme_msg, strlen(readme_msg));
1869 }
1870
1871 static struct file_operations tracing_readme_fops = {
1872 .open = tracing_open_generic,
1873 .read = tracing_readme_read,
1874 };
1875
1876 static ssize_t
1877 tracing_ctrl_read(struct file *filp, char __user *ubuf,
1878 size_t cnt, loff_t *ppos)
1879 {
1880 struct trace_array *tr = filp->private_data;
1881 char buf[64];
1882 int r;
1883
1884 r = sprintf(buf, "%ld\n", tr->ctrl);
1885 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1886 }
1887
1888 static ssize_t
1889 tracing_ctrl_write(struct file *filp, const char __user *ubuf,
1890 size_t cnt, loff_t *ppos)
1891 {
1892 struct trace_array *tr = filp->private_data;
1893 long val;
1894 char buf[64];
1895
1896 if (cnt > 63)
1897 cnt = 63;
1898
1899 if (copy_from_user(&buf, ubuf, cnt))
1900 return -EFAULT;
1901
1902 buf[cnt] = 0;
1903
1904 val = simple_strtoul(buf, NULL, 10);
1905
1906 val = !!val;
1907
1908 mutex_lock(&trace_types_lock);
1909 if (tr->ctrl ^ val) {
1910 if (val)
1911 tracer_enabled = 1;
1912 else
1913 tracer_enabled = 0;
1914
1915 tr->ctrl = val;
1916
1917 if (current_trace && current_trace->ctrl_update)
1918 current_trace->ctrl_update(tr);
1919 }
1920 mutex_unlock(&trace_types_lock);
1921
1922 filp->f_pos += cnt;
1923
1924 return cnt;
1925 }
1926
1927 static ssize_t
1928 tracing_set_trace_read(struct file *filp, char __user *ubuf,
1929 size_t cnt, loff_t *ppos)
1930 {
1931 char buf[max_tracer_type_len+2];
1932 int r;
1933
1934 mutex_lock(&trace_types_lock);
1935 if (current_trace)
1936 r = sprintf(buf, "%s\n", current_trace->name);
1937 else
1938 r = sprintf(buf, "\n");
1939 mutex_unlock(&trace_types_lock);
1940
1941 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1942 }
1943
1944 static ssize_t
1945 tracing_set_trace_write(struct file *filp, const char __user *ubuf,
1946 size_t cnt, loff_t *ppos)
1947 {
1948 struct trace_array *tr = &global_trace;
1949 struct tracer *t;
1950 char buf[max_tracer_type_len+1];
1951 int i;
1952
1953 if (cnt > max_tracer_type_len)
1954 cnt = max_tracer_type_len;
1955
1956 if (copy_from_user(&buf, ubuf, cnt))
1957 return -EFAULT;
1958
1959 buf[cnt] = 0;
1960
1961 /* strip ending whitespace. */
1962 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
1963 buf[i] = 0;
1964
1965 mutex_lock(&trace_types_lock);
1966 for (t = trace_types; t; t = t->next) {
1967 if (strcmp(t->name, buf) == 0)
1968 break;
1969 }
1970 if (!t || t == current_trace)
1971 goto out;
1972
1973 if (current_trace && current_trace->reset)
1974 current_trace->reset(tr);
1975
1976 current_trace = t;
1977 if (t->init)
1978 t->init(tr);
1979
1980 out:
1981 mutex_unlock(&trace_types_lock);
1982
1983 filp->f_pos += cnt;
1984
1985 return cnt;
1986 }
1987
1988 static ssize_t
1989 tracing_max_lat_read(struct file *filp, char __user *ubuf,
1990 size_t cnt, loff_t *ppos)
1991 {
1992 unsigned long *ptr = filp->private_data;
1993 char buf[64];
1994 int r;
1995
1996 r = snprintf(buf, 64, "%ld\n",
1997 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
1998 if (r > 64)
1999 r = 64;
2000 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2001 }
2002
2003 static ssize_t
2004 tracing_max_lat_write(struct file *filp, const char __user *ubuf,
2005 size_t cnt, loff_t *ppos)
2006 {
2007 long *ptr = filp->private_data;
2008 long val;
2009 char buf[64];
2010
2011 if (cnt > 63)
2012 cnt = 63;
2013
2014 if (copy_from_user(&buf, ubuf, cnt))
2015 return -EFAULT;
2016
2017 buf[cnt] = 0;
2018
2019 val = simple_strtoul(buf, NULL, 10);
2020
2021 *ptr = val * 1000;
2022
2023 return cnt;
2024 }
2025
2026 static atomic_t tracing_reader;
2027
2028 static int tracing_open_pipe(struct inode *inode, struct file *filp)
2029 {
2030 struct trace_iterator *iter;
2031
2032 if (tracing_disabled)
2033 return -ENODEV;
2034
2035 /* We only allow for reader of the pipe */
2036 if (atomic_inc_return(&tracing_reader) != 1) {
2037 atomic_dec(&tracing_reader);
2038 return -EBUSY;
2039 }
2040
2041 /* create a buffer to store the information to pass to userspace */
2042 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2043 if (!iter)
2044 return -ENOMEM;
2045
2046 iter->tr = &global_trace;
2047
2048 filp->private_data = iter;
2049
2050 return 0;
2051 }
2052
2053 static int tracing_release_pipe(struct inode *inode, struct file *file)
2054 {
2055 struct trace_iterator *iter = file->private_data;
2056
2057 kfree(iter);
2058 atomic_dec(&tracing_reader);
2059
2060 return 0;
2061 }
2062
2063 static unsigned int
2064 tracing_poll_pipe(struct file *filp, poll_table *poll_table)
2065 {
2066 struct trace_iterator *iter = filp->private_data;
2067
2068 if (trace_flags & TRACE_ITER_BLOCK) {
2069 /*
2070 * Always select as readable when in blocking mode
2071 */
2072 return POLLIN | POLLRDNORM;
2073 }
2074 else {
2075 if (!trace_empty(iter))
2076 return POLLIN | POLLRDNORM;
2077 poll_wait(filp, &trace_wait, poll_table);
2078 if (!trace_empty(iter))
2079 return POLLIN | POLLRDNORM;
2080
2081 return 0;
2082 }
2083 }
2084
2085 /*
2086 * Consumer reader.
2087 */
2088 static ssize_t
2089 tracing_read_pipe(struct file *filp, char __user *ubuf,
2090 size_t cnt, loff_t *ppos)
2091 {
2092 struct trace_iterator *iter = filp->private_data;
2093 struct trace_array_cpu *data;
2094 static cpumask_t mask;
2095 static int start;
2096 unsigned long flags;
2097 #ifdef CONFIG_FTRACE
2098 int ftrace_save;
2099 #endif
2100 int read = 0;
2101 int cpu;
2102 int len;
2103 int ret;
2104
2105 /* return any leftover data */
2106 if (iter->seq.len > start) {
2107 len = iter->seq.len - start;
2108 if (cnt > len)
2109 cnt = len;
2110 ret = copy_to_user(ubuf, iter->seq.buffer + start, cnt);
2111 if (ret)
2112 cnt = -EFAULT;
2113
2114 start += len;
2115
2116 return cnt;
2117 }
2118
2119 trace_seq_reset(&iter->seq);
2120 start = 0;
2121
2122 while (trace_empty(iter)) {
2123 if (!(trace_flags & TRACE_ITER_BLOCK))
2124 return -EWOULDBLOCK;
2125 /*
2126 * This is a make-shift waitqueue. The reason we don't use
2127 * an actual wait queue is because:
2128 * 1) we only ever have one waiter
2129 * 2) the tracing, traces all functions, we don't want
2130 * the overhead of calling wake_up and friends
2131 * (and tracing them too)
2132 * Anyway, this is really very primitive wakeup.
2133 */
2134 set_current_state(TASK_INTERRUPTIBLE);
2135 iter->tr->waiter = current;
2136
2137 /* sleep for one second, and try again. */
2138 schedule_timeout(HZ);
2139
2140 iter->tr->waiter = NULL;
2141
2142 if (signal_pending(current))
2143 return -EINTR;
2144
2145 /*
2146 * We block until we read something and tracing is disabled.
2147 * We still block if tracing is disabled, but we have never
2148 * read anything. This allows a user to cat this file, and
2149 * then enable tracing. But after we have read something,
2150 * we give an EOF when tracing is again disabled.
2151 *
2152 * iter->pos will be 0 if we haven't read anything.
2153 */
2154 if (!tracer_enabled && iter->pos)
2155 break;
2156
2157 continue;
2158 }
2159
2160 /* stop when tracing is finished */
2161 if (trace_empty(iter))
2162 return 0;
2163
2164 if (cnt >= PAGE_SIZE)
2165 cnt = PAGE_SIZE - 1;
2166
2167 memset(iter, 0, sizeof(*iter));
2168 iter->tr = &global_trace;
2169 iter->pos = -1;
2170
2171 /*
2172 * We need to stop all tracing on all CPUS to read the
2173 * the next buffer. This is a bit expensive, but is
2174 * not done often. We fill all what we can read,
2175 * and then release the locks again.
2176 */
2177
2178 cpus_clear(mask);
2179 local_irq_save(flags);
2180 #ifdef CONFIG_FTRACE
2181 ftrace_save = ftrace_enabled;
2182 ftrace_enabled = 0;
2183 #endif
2184 smp_wmb();
2185 for_each_possible_cpu(cpu) {
2186 data = iter->tr->data[cpu];
2187
2188 if (!head_page(data) || !data->trace_idx)
2189 continue;
2190
2191 atomic_inc(&data->disabled);
2192 cpu_set(cpu, mask);
2193 }
2194
2195 for_each_cpu_mask(cpu, mask) {
2196 data = iter->tr->data[cpu];
2197 spin_lock(&data->lock);
2198 }
2199
2200 while (find_next_entry_inc(iter) != NULL) {
2201 int len = iter->seq.len;
2202
2203 ret = print_trace_line(iter);
2204 if (!ret) {
2205 /* don't print partial lines */
2206 iter->seq.len = len;
2207 break;
2208 }
2209
2210 trace_consume(iter);
2211
2212 if (iter->seq.len >= cnt)
2213 break;
2214 }
2215
2216 for_each_cpu_mask(cpu, mask) {
2217 data = iter->tr->data[cpu];
2218 spin_unlock(&data->lock);
2219 }
2220
2221 for_each_cpu_mask(cpu, mask) {
2222 data = iter->tr->data[cpu];
2223 atomic_dec(&data->disabled);
2224 }
2225 #ifdef CONFIG_FTRACE
2226 ftrace_enabled = ftrace_save;
2227 #endif
2228 local_irq_restore(flags);
2229
2230 /* Now copy what we have to the user */
2231 read = iter->seq.len;
2232 if (read > cnt)
2233 read = cnt;
2234
2235 ret = copy_to_user(ubuf, iter->seq.buffer, read);
2236
2237 if (read < iter->seq.len)
2238 start = read;
2239 else
2240 trace_seq_reset(&iter->seq);
2241
2242 if (ret)
2243 read = -EFAULT;
2244
2245 return read;
2246 }
2247
2248 static struct file_operations tracing_max_lat_fops = {
2249 .open = tracing_open_generic,
2250 .read = tracing_max_lat_read,
2251 .write = tracing_max_lat_write,
2252 };
2253
2254 static struct file_operations tracing_ctrl_fops = {
2255 .open = tracing_open_generic,
2256 .read = tracing_ctrl_read,
2257 .write = tracing_ctrl_write,
2258 };
2259
2260 static struct file_operations set_tracer_fops = {
2261 .open = tracing_open_generic,
2262 .read = tracing_set_trace_read,
2263 .write = tracing_set_trace_write,
2264 };
2265
2266 static struct file_operations tracing_pipe_fops = {
2267 .open = tracing_open_pipe,
2268 .poll = tracing_poll_pipe,
2269 .read = tracing_read_pipe,
2270 .release = tracing_release_pipe,
2271 };
2272
2273 #ifdef CONFIG_DYNAMIC_FTRACE
2274
2275 static ssize_t
2276 tracing_read_long(struct file *filp, char __user *ubuf,
2277 size_t cnt, loff_t *ppos)
2278 {
2279 unsigned long *p = filp->private_data;
2280 char buf[64];
2281 int r;
2282
2283 r = sprintf(buf, "%ld\n", *p);
2284
2285 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2286 }
2287
2288 static struct file_operations tracing_read_long_fops = {
2289 .open = tracing_open_generic,
2290 .read = tracing_read_long,
2291 };
2292 #endif
2293
2294 static struct dentry *d_tracer;
2295
2296 struct dentry *tracing_init_dentry(void)
2297 {
2298 static int once;
2299
2300 if (d_tracer)
2301 return d_tracer;
2302
2303 d_tracer = debugfs_create_dir("tracing", NULL);
2304
2305 if (!d_tracer && !once) {
2306 once = 1;
2307 pr_warning("Could not create debugfs directory 'tracing'\n");
2308 return NULL;
2309 }
2310
2311 return d_tracer;
2312 }
2313
2314 #ifdef CONFIG_FTRACE_SELFTEST
2315 /* Let selftest have access to static functions in this file */
2316 #include "trace_selftest.c"
2317 #endif
2318
2319 static __init void tracer_init_debugfs(void)
2320 {
2321 struct dentry *d_tracer;
2322 struct dentry *entry;
2323
2324 d_tracer = tracing_init_dentry();
2325
2326 entry = debugfs_create_file("tracing_enabled", 0644, d_tracer,
2327 &global_trace, &tracing_ctrl_fops);
2328 if (!entry)
2329 pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
2330
2331 entry = debugfs_create_file("iter_ctrl", 0644, d_tracer,
2332 NULL, &tracing_iter_fops);
2333 if (!entry)
2334 pr_warning("Could not create debugfs 'iter_ctrl' entry\n");
2335
2336 entry = debugfs_create_file("latency_trace", 0444, d_tracer,
2337 &global_trace, &tracing_lt_fops);
2338 if (!entry)
2339 pr_warning("Could not create debugfs 'latency_trace' entry\n");
2340
2341 entry = debugfs_create_file("trace", 0444, d_tracer,
2342 &global_trace, &tracing_fops);
2343 if (!entry)
2344 pr_warning("Could not create debugfs 'trace' entry\n");
2345
2346 entry = debugfs_create_file("available_tracers", 0444, d_tracer,
2347 &global_trace, &show_traces_fops);
2348 if (!entry)
2349 pr_warning("Could not create debugfs 'trace' entry\n");
2350
2351 entry = debugfs_create_file("current_tracer", 0444, d_tracer,
2352 &global_trace, &set_tracer_fops);
2353 if (!entry)
2354 pr_warning("Could not create debugfs 'trace' entry\n");
2355
2356 entry = debugfs_create_file("tracing_max_latency", 0644, d_tracer,
2357 &tracing_max_latency,
2358 &tracing_max_lat_fops);
2359 if (!entry)
2360 pr_warning("Could not create debugfs "
2361 "'tracing_max_latency' entry\n");
2362
2363 entry = debugfs_create_file("tracing_thresh", 0644, d_tracer,
2364 &tracing_thresh, &tracing_max_lat_fops);
2365 if (!entry)
2366 pr_warning("Could not create debugfs "
2367 "'tracing_threash' entry\n");
2368 entry = debugfs_create_file("README", 0644, d_tracer,
2369 NULL, &tracing_readme_fops);
2370 if (!entry)
2371 pr_warning("Could not create debugfs 'README' entry\n");
2372
2373 entry = debugfs_create_file("trace_pipe", 0644, d_tracer,
2374 NULL, &tracing_pipe_fops);
2375 if (!entry)
2376 pr_warning("Could not create debugfs "
2377 "'tracing_threash' entry\n");
2378
2379 #ifdef CONFIG_DYNAMIC_FTRACE
2380 entry = debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer,
2381 &ftrace_update_tot_cnt,
2382 &tracing_read_long_fops);
2383 if (!entry)
2384 pr_warning("Could not create debugfs "
2385 "'dyn_ftrace_total_info' entry\n");
2386 #endif
2387 }
2388
2389 /* dummy trace to disable tracing */
2390 static struct tracer no_tracer __read_mostly =
2391 {
2392 .name = "none",
2393 };
2394
2395 static int trace_alloc_page(void)
2396 {
2397 struct trace_array_cpu *data;
2398 struct page *page, *tmp;
2399 LIST_HEAD(pages);
2400 void *array;
2401 int i;
2402
2403 /* first allocate a page for each CPU */
2404 for_each_possible_cpu(i) {
2405 array = (void *)__get_free_page(GFP_KERNEL);
2406 if (array == NULL) {
2407 printk(KERN_ERR "tracer: failed to allocate page"
2408 "for trace buffer!\n");
2409 goto free_pages;
2410 }
2411
2412 page = virt_to_page(array);
2413 list_add(&page->lru, &pages);
2414
2415 /* Only allocate if we are actually using the max trace */
2416 #ifdef CONFIG_TRACER_MAX_TRACE
2417 array = (void *)__get_free_page(GFP_KERNEL);
2418 if (array == NULL) {
2419 printk(KERN_ERR "tracer: failed to allocate page"
2420 "for trace buffer!\n");
2421 goto free_pages;
2422 }
2423 page = virt_to_page(array);
2424 list_add(&page->lru, &pages);
2425 #endif
2426 }
2427
2428 /* Now that we successfully allocate a page per CPU, add them */
2429 for_each_possible_cpu(i) {
2430 data = global_trace.data[i];
2431 spin_lock_init(&data->lock);
2432 lockdep_set_class(&data->lock, &data->lock_key);
2433 page = list_entry(pages.next, struct page, lru);
2434 list_del_init(&page->lru);
2435 list_add_tail(&page->lru, &data->trace_pages);
2436 ClearPageLRU(page);
2437
2438 #ifdef CONFIG_TRACER_MAX_TRACE
2439 data = max_tr.data[i];
2440 spin_lock_init(&data->lock);
2441 lockdep_set_class(&data->lock, &data->lock_key);
2442 page = list_entry(pages.next, struct page, lru);
2443 list_del_init(&page->lru);
2444 list_add_tail(&page->lru, &data->trace_pages);
2445 SetPageLRU(page);
2446 #endif
2447 }
2448 global_trace.entries += ENTRIES_PER_PAGE;
2449
2450 return 0;
2451
2452 free_pages:
2453 list_for_each_entry_safe(page, tmp, &pages, lru) {
2454 list_del_init(&page->lru);
2455 __free_page(page);
2456 }
2457 return -ENOMEM;
2458 }
2459
2460 __init static int tracer_alloc_buffers(void)
2461 {
2462 struct trace_array_cpu *data;
2463 void *array;
2464 struct page *page;
2465 int pages = 0;
2466 int ret = -ENOMEM;
2467 int i;
2468
2469 global_trace.ctrl = tracer_enabled;
2470
2471 /* Allocate the first page for all buffers */
2472 for_each_possible_cpu(i) {
2473 data = global_trace.data[i] = &per_cpu(global_trace_cpu, i);
2474 max_tr.data[i] = &per_cpu(max_data, i);
2475
2476 array = (void *)__get_free_page(GFP_KERNEL);
2477 if (array == NULL) {
2478 printk(KERN_ERR "tracer: failed to allocate page"
2479 "for trace buffer!\n");
2480 goto free_buffers;
2481 }
2482
2483 /* set the array to the list */
2484 INIT_LIST_HEAD(&data->trace_pages);
2485 page = virt_to_page(array);
2486 list_add(&page->lru, &data->trace_pages);
2487 /* use the LRU flag to differentiate the two buffers */
2488 ClearPageLRU(page);
2489
2490 /* Only allocate if we are actually using the max trace */
2491 #ifdef CONFIG_TRACER_MAX_TRACE
2492 array = (void *)__get_free_page(GFP_KERNEL);
2493 if (array == NULL) {
2494 printk(KERN_ERR "tracer: failed to allocate page"
2495 "for trace buffer!\n");
2496 goto free_buffers;
2497 }
2498
2499 INIT_LIST_HEAD(&max_tr.data[i]->trace_pages);
2500 page = virt_to_page(array);
2501 list_add(&page->lru, &max_tr.data[i]->trace_pages);
2502 SetPageLRU(page);
2503 #endif
2504 }
2505
2506 /*
2507 * Since we allocate by orders of pages, we may be able to
2508 * round up a bit.
2509 */
2510 global_trace.entries = ENTRIES_PER_PAGE;
2511 pages++;
2512
2513 while (global_trace.entries < trace_nr_entries) {
2514 if (trace_alloc_page())
2515 break;
2516 pages++;
2517 }
2518 max_tr.entries = global_trace.entries;
2519
2520 pr_info("tracer: %d pages allocated for %ld",
2521 pages, trace_nr_entries);
2522 pr_info(" entries of %ld bytes\n", (long)TRACE_ENTRY_SIZE);
2523 pr_info(" actual entries %ld\n", global_trace.entries);
2524
2525 tracer_init_debugfs();
2526
2527 trace_init_cmdlines();
2528
2529 register_tracer(&no_tracer);
2530 current_trace = &no_tracer;
2531
2532 /* All seems OK, enable tracing */
2533 tracing_disabled = 0;
2534
2535 return 0;
2536
2537 free_buffers:
2538 for (i-- ; i >= 0; i--) {
2539 struct page *page, *tmp;
2540 struct trace_array_cpu *data = global_trace.data[i];
2541
2542 if (data) {
2543 list_for_each_entry_safe(page, tmp,
2544 &data->trace_pages, lru) {
2545 list_del_init(&page->lru);
2546 __free_page(page);
2547 }
2548 }
2549
2550 #ifdef CONFIG_TRACER_MAX_TRACE
2551 data = max_tr.data[i];
2552 if (data) {
2553 list_for_each_entry_safe(page, tmp,
2554 &data->trace_pages, lru) {
2555 list_del_init(&page->lru);
2556 __free_page(page);
2557 }
2558 }
2559 #endif
2560 }
2561 return ret;
2562 }
2563 fs_initcall(tracer_alloc_buffers);
Linux kernel - Deliverables
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