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ftrace: remove wakeup from function trace
[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 "sched-tree",
133 NULL
134 };
135
136 static DEFINE_SPINLOCK(ftrace_max_lock);
137
138 /*
139 * Copy the new maximum trace into the separate maximum-trace
140 * structure. (this way the maximum trace is permanently saved,
141 * for later retrieval via /debugfs/tracing/latency_trace)
142 */
143 static void
144 __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
145 {
146 struct trace_array_cpu *data = tr->data[cpu];
147
148 max_tr.cpu = cpu;
149 max_tr.time_start = data->preempt_timestamp;
150
151 data = max_tr.data[cpu];
152 data->saved_latency = tracing_max_latency;
153
154 memcpy(data->comm, tsk->comm, TASK_COMM_LEN);
155 data->pid = tsk->pid;
156 data->uid = tsk->uid;
157 data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
158 data->policy = tsk->policy;
159 data->rt_priority = tsk->rt_priority;
160
161 /* record this tasks comm */
162 tracing_record_cmdline(current);
163 }
164
165 void check_pages(struct trace_array_cpu *data)
166 {
167 struct page *page, *tmp;
168
169 BUG_ON(data->trace_pages.next->prev != &data->trace_pages);
170 BUG_ON(data->trace_pages.prev->next != &data->trace_pages);
171
172 list_for_each_entry_safe(page, tmp, &data->trace_pages, lru) {
173 BUG_ON(page->lru.next->prev != &page->lru);
174 BUG_ON(page->lru.prev->next != &page->lru);
175 }
176 }
177
178 void *head_page(struct trace_array_cpu *data)
179 {
180 struct page *page;
181
182 check_pages(data);
183 if (list_empty(&data->trace_pages))
184 return NULL;
185
186 page = list_entry(data->trace_pages.next, struct page, lru);
187 BUG_ON(&page->lru == &data->trace_pages);
188
189 return page_address(page);
190 }
191
192 static int
193 trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
194 {
195 int len = (PAGE_SIZE - 1) - s->len;
196 va_list ap;
197 int ret;
198
199 if (!len)
200 return 0;
201
202 va_start(ap, fmt);
203 ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
204 va_end(ap);
205
206 /* If we can't write it all, don't bother writing anything */
207 if (ret > len)
208 return 0;
209
210 s->len += ret;
211
212 return len;
213 }
214
215 static int
216 trace_seq_puts(struct trace_seq *s, const char *str)
217 {
218 int len = strlen(str);
219
220 if (len > ((PAGE_SIZE - 1) - s->len))
221 return 0;
222
223 memcpy(s->buffer + s->len, str, len);
224 s->len += len;
225
226 return len;
227 }
228
229 static int
230 trace_seq_putc(struct trace_seq *s, unsigned char c)
231 {
232 if (s->len >= (PAGE_SIZE - 1))
233 return 0;
234
235 s->buffer[s->len++] = c;
236
237 return 1;
238 }
239
240 static int
241 trace_seq_putmem(struct trace_seq *s, void *mem, size_t len)
242 {
243 if (len > ((PAGE_SIZE - 1) - s->len))
244 return 0;
245
246 memcpy(s->buffer + s->len, mem, len);
247 s->len += len;
248
249 return len;
250 }
251
252 #define HEX_CHARS 17
253
254 static int
255 trace_seq_putmem_hex(struct trace_seq *s, void *mem, size_t len)
256 {
257 unsigned char hex[HEX_CHARS];
258 unsigned char *data;
259 unsigned char byte;
260 int i, j;
261
262 BUG_ON(len >= HEX_CHARS);
263
264 data = mem;
265
266 #ifdef __BIG_ENDIAN
267 for (i = 0, j = 0; i < len; i++) {
268 #else
269 for (i = len-1, j = 0; i >= 0; i--) {
270 #endif
271 byte = data[i];
272
273 hex[j] = byte & 0x0f;
274 if (hex[j] >= 10)
275 hex[j] += 'a' - 10;
276 else
277 hex[j] += '0';
278 j++;
279
280 hex[j] = byte >> 4;
281 if (hex[j] >= 10)
282 hex[j] += 'a' - 10;
283 else
284 hex[j] += '0';
285 j++;
286 }
287 hex[j] = ' ';
288 j++;
289
290 return trace_seq_putmem(s, hex, j);
291 }
292
293 static void
294 trace_seq_reset(struct trace_seq *s)
295 {
296 s->len = 0;
297 }
298
299 static void
300 trace_print_seq(struct seq_file *m, struct trace_seq *s)
301 {
302 int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
303
304 s->buffer[len] = 0;
305 seq_puts(m, s->buffer);
306
307 trace_seq_reset(s);
308 }
309
310 static void
311 flip_trace(struct trace_array_cpu *tr1, struct trace_array_cpu *tr2)
312 {
313 struct list_head flip_pages;
314
315 INIT_LIST_HEAD(&flip_pages);
316
317 memcpy(&tr1->trace_head_idx, &tr2->trace_head_idx,
318 sizeof(struct trace_array_cpu) -
319 offsetof(struct trace_array_cpu, trace_head_idx));
320
321 check_pages(tr1);
322 check_pages(tr2);
323 list_splice_init(&tr1->trace_pages, &flip_pages);
324 list_splice_init(&tr2->trace_pages, &tr1->trace_pages);
325 list_splice_init(&flip_pages, &tr2->trace_pages);
326 BUG_ON(!list_empty(&flip_pages));
327 check_pages(tr1);
328 check_pages(tr2);
329 }
330
331 void
332 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
333 {
334 struct trace_array_cpu *data;
335 int i;
336
337 WARN_ON_ONCE(!irqs_disabled());
338 spin_lock(&ftrace_max_lock);
339 /* clear out all the previous traces */
340 for_each_possible_cpu(i) {
341 data = tr->data[i];
342 flip_trace(max_tr.data[i], data);
343 tracing_reset(data);
344 }
345
346 __update_max_tr(tr, tsk, cpu);
347 spin_unlock(&ftrace_max_lock);
348 }
349
350 /**
351 * update_max_tr_single - only copy one trace over, and reset the rest
352 * @tr - tracer
353 * @tsk - task with the latency
354 * @cpu - the cpu of the buffer to copy.
355 */
356 void
357 update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
358 {
359 struct trace_array_cpu *data = tr->data[cpu];
360 int i;
361
362 WARN_ON_ONCE(!irqs_disabled());
363 spin_lock(&ftrace_max_lock);
364 for_each_possible_cpu(i)
365 tracing_reset(max_tr.data[i]);
366
367 flip_trace(max_tr.data[cpu], data);
368 tracing_reset(data);
369
370 __update_max_tr(tr, tsk, cpu);
371 spin_unlock(&ftrace_max_lock);
372 }
373
374 int register_tracer(struct tracer *type)
375 {
376 struct tracer *t;
377 int len;
378 int ret = 0;
379
380 if (!type->name) {
381 pr_info("Tracer must have a name\n");
382 return -1;
383 }
384
385 mutex_lock(&trace_types_lock);
386 for (t = trace_types; t; t = t->next) {
387 if (strcmp(type->name, t->name) == 0) {
388 /* already found */
389 pr_info("Trace %s already registered\n",
390 type->name);
391 ret = -1;
392 goto out;
393 }
394 }
395
396 #ifdef CONFIG_FTRACE_STARTUP_TEST
397 if (type->selftest) {
398 struct tracer *saved_tracer = current_trace;
399 struct trace_array_cpu *data;
400 struct trace_array *tr = &global_trace;
401 int saved_ctrl = tr->ctrl;
402 int i;
403 /*
404 * Run a selftest on this tracer.
405 * Here we reset the trace buffer, and set the current
406 * tracer to be this tracer. The tracer can then run some
407 * internal tracing to verify that everything is in order.
408 * If we fail, we do not register this tracer.
409 */
410 for_each_possible_cpu(i) {
411 data = tr->data[i];
412 if (!head_page(data))
413 continue;
414 tracing_reset(data);
415 }
416 current_trace = type;
417 tr->ctrl = 0;
418 /* the test is responsible for initializing and enabling */
419 pr_info("Testing tracer %s: ", type->name);
420 ret = type->selftest(type, tr);
421 /* the test is responsible for resetting too */
422 current_trace = saved_tracer;
423 tr->ctrl = saved_ctrl;
424 if (ret) {
425 printk(KERN_CONT "FAILED!\n");
426 goto out;
427 }
428 /* Only reset on passing, to avoid touching corrupted buffers */
429 for_each_possible_cpu(i) {
430 data = tr->data[i];
431 if (!head_page(data))
432 continue;
433 tracing_reset(data);
434 }
435 printk(KERN_CONT "PASSED\n");
436 }
437 #endif
438
439 type->next = trace_types;
440 trace_types = type;
441 len = strlen(type->name);
442 if (len > max_tracer_type_len)
443 max_tracer_type_len = len;
444
445 out:
446 mutex_unlock(&trace_types_lock);
447
448 return ret;
449 }
450
451 void unregister_tracer(struct tracer *type)
452 {
453 struct tracer **t;
454 int len;
455
456 mutex_lock(&trace_types_lock);
457 for (t = &trace_types; *t; t = &(*t)->next) {
458 if (*t == type)
459 goto found;
460 }
461 pr_info("Trace %s not registered\n", type->name);
462 goto out;
463
464 found:
465 *t = (*t)->next;
466 if (strlen(type->name) != max_tracer_type_len)
467 goto out;
468
469 max_tracer_type_len = 0;
470 for (t = &trace_types; *t; t = &(*t)->next) {
471 len = strlen((*t)->name);
472 if (len > max_tracer_type_len)
473 max_tracer_type_len = len;
474 }
475 out:
476 mutex_unlock(&trace_types_lock);
477 }
478
479 void tracing_reset(struct trace_array_cpu *data)
480 {
481 data->trace_idx = 0;
482 data->trace_head = data->trace_tail = head_page(data);
483 data->trace_head_idx = 0;
484 data->trace_tail_idx = 0;
485 }
486
487 #define SAVED_CMDLINES 128
488 static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
489 static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
490 static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
491 static int cmdline_idx;
492 static DEFINE_SPINLOCK(trace_cmdline_lock);
493 atomic_t trace_record_cmdline_disabled;
494
495 static void trace_init_cmdlines(void)
496 {
497 memset(&map_pid_to_cmdline, -1, sizeof(map_pid_to_cmdline));
498 memset(&map_cmdline_to_pid, -1, sizeof(map_cmdline_to_pid));
499 cmdline_idx = 0;
500 }
501
502 void trace_stop_cmdline_recording(void);
503
504 static void trace_save_cmdline(struct task_struct *tsk)
505 {
506 unsigned map;
507 unsigned idx;
508
509 if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
510 return;
511
512 /*
513 * It's not the end of the world if we don't get
514 * the lock, but we also don't want to spin
515 * nor do we want to disable interrupts,
516 * so if we miss here, then better luck next time.
517 */
518 if (!spin_trylock(&trace_cmdline_lock))
519 return;
520
521 idx = map_pid_to_cmdline[tsk->pid];
522 if (idx >= SAVED_CMDLINES) {
523 idx = (cmdline_idx + 1) % SAVED_CMDLINES;
524
525 map = map_cmdline_to_pid[idx];
526 if (map <= PID_MAX_DEFAULT)
527 map_pid_to_cmdline[map] = (unsigned)-1;
528
529 map_pid_to_cmdline[tsk->pid] = idx;
530
531 cmdline_idx = idx;
532 }
533
534 memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
535
536 spin_unlock(&trace_cmdline_lock);
537 }
538
539 static char *trace_find_cmdline(int pid)
540 {
541 char *cmdline = "<...>";
542 unsigned map;
543
544 if (!pid)
545 return "<idle>";
546
547 if (pid > PID_MAX_DEFAULT)
548 goto out;
549
550 map = map_pid_to_cmdline[pid];
551 if (map >= SAVED_CMDLINES)
552 goto out;
553
554 cmdline = saved_cmdlines[map];
555
556 out:
557 return cmdline;
558 }
559
560 void tracing_record_cmdline(struct task_struct *tsk)
561 {
562 if (atomic_read(&trace_record_cmdline_disabled))
563 return;
564
565 trace_save_cmdline(tsk);
566 }
567
568 static inline struct list_head *
569 trace_next_list(struct trace_array_cpu *data, struct list_head *next)
570 {
571 /*
572 * Roundrobin - but skip the head (which is not a real page):
573 */
574 next = next->next;
575 if (unlikely(next == &data->trace_pages))
576 next = next->next;
577 BUG_ON(next == &data->trace_pages);
578
579 return next;
580 }
581
582 static inline void *
583 trace_next_page(struct trace_array_cpu *data, void *addr)
584 {
585 struct list_head *next;
586 struct page *page;
587
588 page = virt_to_page(addr);
589
590 next = trace_next_list(data, &page->lru);
591 page = list_entry(next, struct page, lru);
592
593 return page_address(page);
594 }
595
596 static inline struct trace_entry *
597 tracing_get_trace_entry(struct trace_array *tr, struct trace_array_cpu *data)
598 {
599 unsigned long idx, idx_next;
600 struct trace_entry *entry;
601
602 data->trace_idx++;
603 idx = data->trace_head_idx;
604 idx_next = idx + 1;
605
606 BUG_ON(idx * TRACE_ENTRY_SIZE >= PAGE_SIZE);
607
608 entry = data->trace_head + idx * TRACE_ENTRY_SIZE;
609
610 if (unlikely(idx_next >= ENTRIES_PER_PAGE)) {
611 data->trace_head = trace_next_page(data, data->trace_head);
612 idx_next = 0;
613 }
614
615 if (data->trace_head == data->trace_tail &&
616 idx_next == data->trace_tail_idx) {
617 /* overrun */
618 data->trace_tail_idx++;
619 if (data->trace_tail_idx >= ENTRIES_PER_PAGE) {
620 data->trace_tail =
621 trace_next_page(data, data->trace_tail);
622 data->trace_tail_idx = 0;
623 }
624 }
625
626 data->trace_head_idx = idx_next;
627
628 return entry;
629 }
630
631 static inline void
632 tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags)
633 {
634 struct task_struct *tsk = current;
635 unsigned long pc;
636
637 pc = preempt_count();
638
639 entry->preempt_count = pc & 0xff;
640 entry->pid = tsk->pid;
641 entry->t = ftrace_now(raw_smp_processor_id());
642 entry->flags = (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
643 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
644 ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
645 (need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
646 }
647
648 void
649 trace_function(struct trace_array *tr, struct trace_array_cpu *data,
650 unsigned long ip, unsigned long parent_ip, unsigned long flags)
651 {
652 struct trace_entry *entry;
653 unsigned long irq_flags;
654
655 spin_lock_irqsave(&data->lock, irq_flags);
656 entry = tracing_get_trace_entry(tr, data);
657 tracing_generic_entry_update(entry, flags);
658 entry->type = TRACE_FN;
659 entry->fn.ip = ip;
660 entry->fn.parent_ip = parent_ip;
661 spin_unlock_irqrestore(&data->lock, irq_flags);
662 }
663
664 void
665 ftrace(struct trace_array *tr, struct trace_array_cpu *data,
666 unsigned long ip, unsigned long parent_ip, unsigned long flags)
667 {
668 if (likely(!atomic_read(&data->disabled)))
669 trace_function(tr, data, ip, parent_ip, flags);
670 }
671
672 void
673 __trace_special(void *__tr, void *__data,
674 unsigned long arg1, unsigned long arg2, unsigned long arg3)
675 {
676 struct trace_array_cpu *data = __data;
677 struct trace_array *tr = __tr;
678 struct trace_entry *entry;
679 unsigned long irq_flags;
680
681 spin_lock_irqsave(&data->lock, irq_flags);
682 entry = tracing_get_trace_entry(tr, data);
683 tracing_generic_entry_update(entry, 0);
684 entry->type = TRACE_SPECIAL;
685 entry->special.arg1 = arg1;
686 entry->special.arg2 = arg2;
687 entry->special.arg3 = arg3;
688 spin_unlock_irqrestore(&data->lock, irq_flags);
689
690 trace_wake_up();
691 }
692
693 void __trace_stack(struct trace_array *tr,
694 struct trace_array_cpu *data,
695 unsigned long flags,
696 int skip)
697 {
698 struct trace_entry *entry;
699 struct stack_trace trace;
700
701 if (!(trace_flags & TRACE_ITER_STACKTRACE))
702 return;
703
704 entry = tracing_get_trace_entry(tr, data);
705 tracing_generic_entry_update(entry, flags);
706 entry->type = TRACE_STACK;
707
708 memset(&entry->stack, 0, sizeof(entry->stack));
709
710 trace.nr_entries = 0;
711 trace.max_entries = FTRACE_STACK_ENTRIES;
712 trace.skip = skip;
713 trace.entries = entry->stack.caller;
714
715 save_stack_trace(&trace);
716 }
717
718 void
719 tracing_sched_switch_trace(struct trace_array *tr,
720 struct trace_array_cpu *data,
721 struct task_struct *prev,
722 struct task_struct *next,
723 unsigned long flags)
724 {
725 struct trace_entry *entry;
726 unsigned long irq_flags;
727
728 spin_lock_irqsave(&data->lock, irq_flags);
729 entry = tracing_get_trace_entry(tr, data);
730 tracing_generic_entry_update(entry, flags);
731 entry->type = TRACE_CTX;
732 entry->ctx.prev_pid = prev->pid;
733 entry->ctx.prev_prio = prev->prio;
734 entry->ctx.prev_state = prev->state;
735 entry->ctx.next_pid = next->pid;
736 entry->ctx.next_prio = next->prio;
737 entry->ctx.next_state = next->state;
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 entry->ctx.next_state = wakee->state;
762 __trace_stack(tr, data, flags, 5);
763 spin_unlock_irqrestore(&data->lock, irq_flags);
764
765 trace_wake_up();
766 }
767
768 #ifdef CONFIG_FTRACE
769 static void
770 function_trace_call(unsigned long ip, unsigned long parent_ip)
771 {
772 struct trace_array *tr = &global_trace;
773 struct trace_array_cpu *data;
774 unsigned long flags;
775 long disabled;
776 int cpu;
777
778 if (unlikely(!tracer_enabled))
779 return;
780
781 local_irq_save(flags);
782 cpu = raw_smp_processor_id();
783 data = tr->data[cpu];
784 disabled = atomic_inc_return(&data->disabled);
785
786 if (likely(disabled == 1))
787 trace_function(tr, data, ip, parent_ip, flags);
788
789 atomic_dec(&data->disabled);
790 local_irq_restore(flags);
791 }
792
793 static struct ftrace_ops trace_ops __read_mostly =
794 {
795 .func = function_trace_call,
796 };
797
798 void tracing_start_function_trace(void)
799 {
800 register_ftrace_function(&trace_ops);
801 }
802
803 void tracing_stop_function_trace(void)
804 {
805 unregister_ftrace_function(&trace_ops);
806 }
807 #endif
808
809 enum trace_file_type {
810 TRACE_FILE_LAT_FMT = 1,
811 };
812
813 static struct trace_entry *
814 trace_entry_idx(struct trace_array *tr, struct trace_array_cpu *data,
815 struct trace_iterator *iter, int cpu)
816 {
817 struct page *page;
818 struct trace_entry *array;
819
820 if (iter->next_idx[cpu] >= tr->entries ||
821 iter->next_idx[cpu] >= data->trace_idx ||
822 (data->trace_head == data->trace_tail &&
823 data->trace_head_idx == data->trace_tail_idx))
824 return NULL;
825
826 if (!iter->next_page[cpu]) {
827 /* Initialize the iterator for this cpu trace buffer */
828 WARN_ON(!data->trace_tail);
829 page = virt_to_page(data->trace_tail);
830 iter->next_page[cpu] = &page->lru;
831 iter->next_page_idx[cpu] = data->trace_tail_idx;
832 }
833
834 page = list_entry(iter->next_page[cpu], struct page, lru);
835 BUG_ON(&data->trace_pages == &page->lru);
836
837 array = page_address(page);
838
839 WARN_ON(iter->next_page_idx[cpu] >= ENTRIES_PER_PAGE);
840 return &array[iter->next_page_idx[cpu]];
841 }
842
843 static struct trace_entry *
844 find_next_entry(struct trace_iterator *iter, int *ent_cpu)
845 {
846 struct trace_array *tr = iter->tr;
847 struct trace_entry *ent, *next = NULL;
848 int next_cpu = -1;
849 int cpu;
850
851 for_each_possible_cpu(cpu) {
852 if (!head_page(tr->data[cpu]))
853 continue;
854 ent = trace_entry_idx(tr, tr->data[cpu], iter, cpu);
855 /*
856 * Pick the entry with the smallest timestamp:
857 */
858 if (ent && (!next || ent->t < next->t)) {
859 next = ent;
860 next_cpu = cpu;
861 }
862 }
863
864 if (ent_cpu)
865 *ent_cpu = next_cpu;
866
867 return next;
868 }
869
870 static void trace_iterator_increment(struct trace_iterator *iter)
871 {
872 iter->idx++;
873 iter->next_idx[iter->cpu]++;
874 iter->next_page_idx[iter->cpu]++;
875
876 if (iter->next_page_idx[iter->cpu] >= ENTRIES_PER_PAGE) {
877 struct trace_array_cpu *data = iter->tr->data[iter->cpu];
878
879 iter->next_page_idx[iter->cpu] = 0;
880 iter->next_page[iter->cpu] =
881 trace_next_list(data, iter->next_page[iter->cpu]);
882 }
883 }
884
885 static void trace_consume(struct trace_iterator *iter)
886 {
887 struct trace_array_cpu *data = iter->tr->data[iter->cpu];
888
889 data->trace_tail_idx++;
890 if (data->trace_tail_idx >= ENTRIES_PER_PAGE) {
891 data->trace_tail = trace_next_page(data, data->trace_tail);
892 data->trace_tail_idx = 0;
893 }
894
895 /* Check if we empty it, then reset the index */
896 if (data->trace_head == data->trace_tail &&
897 data->trace_head_idx == data->trace_tail_idx)
898 data->trace_idx = 0;
899 }
900
901 static void *find_next_entry_inc(struct trace_iterator *iter)
902 {
903 struct trace_entry *next;
904 int next_cpu = -1;
905
906 next = find_next_entry(iter, &next_cpu);
907
908 iter->prev_ent = iter->ent;
909 iter->prev_cpu = iter->cpu;
910
911 iter->ent = next;
912 iter->cpu = next_cpu;
913
914 if (next)
915 trace_iterator_increment(iter);
916
917 return next ? iter : NULL;
918 }
919
920 static void *s_next(struct seq_file *m, void *v, loff_t *pos)
921 {
922 struct trace_iterator *iter = m->private;
923 void *last_ent = iter->ent;
924 int i = (int)*pos;
925 void *ent;
926
927 (*pos)++;
928
929 /* can't go backwards */
930 if (iter->idx > i)
931 return NULL;
932
933 if (iter->idx < 0)
934 ent = find_next_entry_inc(iter);
935 else
936 ent = iter;
937
938 while (ent && iter->idx < i)
939 ent = find_next_entry_inc(iter);
940
941 iter->pos = *pos;
942
943 if (last_ent && !ent)
944 seq_puts(m, "\n\nvim:ft=help\n");
945
946 return ent;
947 }
948
949 static void *s_start(struct seq_file *m, loff_t *pos)
950 {
951 struct trace_iterator *iter = m->private;
952 void *p = NULL;
953 loff_t l = 0;
954 int i;
955
956 mutex_lock(&trace_types_lock);
957
958 if (!current_trace || current_trace != iter->trace)
959 return NULL;
960
961 atomic_inc(&trace_record_cmdline_disabled);
962
963 /* let the tracer grab locks here if needed */
964 if (current_trace->start)
965 current_trace->start(iter);
966
967 if (*pos != iter->pos) {
968 iter->ent = NULL;
969 iter->cpu = 0;
970 iter->idx = -1;
971 iter->prev_ent = NULL;
972 iter->prev_cpu = -1;
973
974 for_each_possible_cpu(i) {
975 iter->next_idx[i] = 0;
976 iter->next_page[i] = NULL;
977 }
978
979 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
980 ;
981
982 } else {
983 l = *pos - 1;
984 p = s_next(m, p, &l);
985 }
986
987 return p;
988 }
989
990 static void s_stop(struct seq_file *m, void *p)
991 {
992 struct trace_iterator *iter = m->private;
993
994 atomic_dec(&trace_record_cmdline_disabled);
995
996 /* let the tracer release locks here if needed */
997 if (current_trace && current_trace == iter->trace && iter->trace->stop)
998 iter->trace->stop(iter);
999
1000 mutex_unlock(&trace_types_lock);
1001 }
1002
1003 static int
1004 seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
1005 {
1006 #ifdef CONFIG_KALLSYMS
1007 char str[KSYM_SYMBOL_LEN];
1008
1009 kallsyms_lookup(address, NULL, NULL, NULL, str);
1010
1011 return trace_seq_printf(s, fmt, str);
1012 #endif
1013 return 1;
1014 }
1015
1016 static int
1017 seq_print_sym_offset(struct trace_seq *s, const char *fmt,
1018 unsigned long address)
1019 {
1020 #ifdef CONFIG_KALLSYMS
1021 char str[KSYM_SYMBOL_LEN];
1022
1023 sprint_symbol(str, address);
1024 return trace_seq_printf(s, fmt, str);
1025 #endif
1026 return 1;
1027 }
1028
1029 #ifndef CONFIG_64BIT
1030 # define IP_FMT "%08lx"
1031 #else
1032 # define IP_FMT "%016lx"
1033 #endif
1034
1035 static int
1036 seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
1037 {
1038 int ret;
1039
1040 if (!ip)
1041 return trace_seq_printf(s, "0");
1042
1043 if (sym_flags & TRACE_ITER_SYM_OFFSET)
1044 ret = seq_print_sym_offset(s, "%s", ip);
1045 else
1046 ret = seq_print_sym_short(s, "%s", ip);
1047
1048 if (!ret)
1049 return 0;
1050
1051 if (sym_flags & TRACE_ITER_SYM_ADDR)
1052 ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
1053 return ret;
1054 }
1055
1056 static void print_lat_help_header(struct seq_file *m)
1057 {
1058 seq_puts(m, "# _------=> CPU# \n");
1059 seq_puts(m, "# / _-----=> irqs-off \n");
1060 seq_puts(m, "# | / _----=> need-resched \n");
1061 seq_puts(m, "# || / _---=> hardirq/softirq \n");
1062 seq_puts(m, "# ||| / _--=> preempt-depth \n");
1063 seq_puts(m, "# |||| / \n");
1064 seq_puts(m, "# ||||| delay \n");
1065 seq_puts(m, "# cmd pid ||||| time | caller \n");
1066 seq_puts(m, "# \\ / ||||| \\ | / \n");
1067 }
1068
1069 static void print_func_help_header(struct seq_file *m)
1070 {
1071 seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1072 seq_puts(m, "# | | | | |\n");
1073 }
1074
1075
1076 static void
1077 print_trace_header(struct seq_file *m, struct trace_iterator *iter)
1078 {
1079 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1080 struct trace_array *tr = iter->tr;
1081 struct trace_array_cpu *data = tr->data[tr->cpu];
1082 struct tracer *type = current_trace;
1083 unsigned long total = 0;
1084 unsigned long entries = 0;
1085 int cpu;
1086 const char *name = "preemption";
1087
1088 if (type)
1089 name = type->name;
1090
1091 for_each_possible_cpu(cpu) {
1092 if (head_page(tr->data[cpu])) {
1093 total += tr->data[cpu]->trace_idx;
1094 if (tr->data[cpu]->trace_idx > tr->entries)
1095 entries += tr->entries;
1096 else
1097 entries += tr->data[cpu]->trace_idx;
1098 }
1099 }
1100
1101 seq_printf(m, "%s latency trace v1.1.5 on %s\n",
1102 name, UTS_RELEASE);
1103 seq_puts(m, "-----------------------------------"
1104 "---------------------------------\n");
1105 seq_printf(m, " latency: %lu us, #%lu/%lu, CPU#%d |"
1106 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1107 nsecs_to_usecs(data->saved_latency),
1108 entries,
1109 total,
1110 tr->cpu,
1111 #if defined(CONFIG_PREEMPT_NONE)
1112 "server",
1113 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1114 "desktop",
1115 #elif defined(CONFIG_PREEMPT_DESKTOP)
1116 "preempt",
1117 #else
1118 "unknown",
1119 #endif
1120 /* These are reserved for later use */
1121 0, 0, 0, 0);
1122 #ifdef CONFIG_SMP
1123 seq_printf(m, " #P:%d)\n", num_online_cpus());
1124 #else
1125 seq_puts(m, ")\n");
1126 #endif
1127 seq_puts(m, " -----------------\n");
1128 seq_printf(m, " | task: %.16s-%d "
1129 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1130 data->comm, data->pid, data->uid, data->nice,
1131 data->policy, data->rt_priority);
1132 seq_puts(m, " -----------------\n");
1133
1134 if (data->critical_start) {
1135 seq_puts(m, " => started at: ");
1136 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
1137 trace_print_seq(m, &iter->seq);
1138 seq_puts(m, "\n => ended at: ");
1139 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
1140 trace_print_seq(m, &iter->seq);
1141 seq_puts(m, "\n");
1142 }
1143
1144 seq_puts(m, "\n");
1145 }
1146
1147 static void
1148 lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
1149 {
1150 int hardirq, softirq;
1151 char *comm;
1152
1153 comm = trace_find_cmdline(entry->pid);
1154
1155 trace_seq_printf(s, "%8.8s-%-5d ", comm, entry->pid);
1156 trace_seq_printf(s, "%d", cpu);
1157 trace_seq_printf(s, "%c%c",
1158 (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' : '.',
1159 ((entry->flags & TRACE_FLAG_NEED_RESCHED) ? 'N' : '.'));
1160
1161 hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
1162 softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
1163 if (hardirq && softirq)
1164 trace_seq_putc(s, 'H');
1165 else {
1166 if (hardirq)
1167 trace_seq_putc(s, 'h');
1168 else {
1169 if (softirq)
1170 trace_seq_putc(s, 's');
1171 else
1172 trace_seq_putc(s, '.');
1173 }
1174 }
1175
1176 if (entry->preempt_count)
1177 trace_seq_printf(s, "%x", entry->preempt_count);
1178 else
1179 trace_seq_puts(s, ".");
1180 }
1181
1182 unsigned long preempt_mark_thresh = 100;
1183
1184 static void
1185 lat_print_timestamp(struct trace_seq *s, unsigned long long abs_usecs,
1186 unsigned long rel_usecs)
1187 {
1188 trace_seq_printf(s, " %4lldus", abs_usecs);
1189 if (rel_usecs > preempt_mark_thresh)
1190 trace_seq_puts(s, "!: ");
1191 else if (rel_usecs > 1)
1192 trace_seq_puts(s, "+: ");
1193 else
1194 trace_seq_puts(s, " : ");
1195 }
1196
1197 static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
1198
1199 static int
1200 print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
1201 {
1202 struct trace_seq *s = &iter->seq;
1203 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1204 struct trace_entry *next_entry = find_next_entry(iter, NULL);
1205 unsigned long verbose = (trace_flags & TRACE_ITER_VERBOSE);
1206 struct trace_entry *entry = iter->ent;
1207 unsigned long abs_usecs;
1208 unsigned long rel_usecs;
1209 char *comm;
1210 int S, T;
1211 int i;
1212
1213 if (!next_entry)
1214 next_entry = entry;
1215 rel_usecs = ns2usecs(next_entry->t - entry->t);
1216 abs_usecs = ns2usecs(entry->t - iter->tr->time_start);
1217
1218 if (verbose) {
1219 comm = trace_find_cmdline(entry->pid);
1220 trace_seq_printf(s, "%16s %5d %d %d %08x %08x [%08lx]"
1221 " %ld.%03ldms (+%ld.%03ldms): ",
1222 comm,
1223 entry->pid, cpu, entry->flags,
1224 entry->preempt_count, trace_idx,
1225 ns2usecs(entry->t),
1226 abs_usecs/1000,
1227 abs_usecs % 1000, rel_usecs/1000,
1228 rel_usecs % 1000);
1229 } else {
1230 lat_print_generic(s, entry, cpu);
1231 lat_print_timestamp(s, abs_usecs, rel_usecs);
1232 }
1233 switch (entry->type) {
1234 case TRACE_FN:
1235 seq_print_ip_sym(s, entry->fn.ip, sym_flags);
1236 trace_seq_puts(s, " (");
1237 seq_print_ip_sym(s, entry->fn.parent_ip, sym_flags);
1238 trace_seq_puts(s, ")\n");
1239 break;
1240 case TRACE_CTX:
1241 case TRACE_WAKE:
1242 S = entry->ctx.prev_state < sizeof(state_to_char) ?
1243 state_to_char[entry->ctx.prev_state] : 'X';
1244 T = entry->ctx.next_state < sizeof(state_to_char) ?
1245 state_to_char[entry->ctx.next_state] : 'X';
1246
1247 comm = trace_find_cmdline(entry->ctx.next_pid);
1248 trace_seq_printf(s, " %5d:%3d:%c %s %5d:%3d:%c %s\n",
1249 entry->ctx.prev_pid,
1250 entry->ctx.prev_prio,
1251 S, entry->type == TRACE_CTX ? "==>" : " +",
1252 entry->ctx.next_pid,
1253 entry->ctx.next_prio,
1254 T, comm);
1255 break;
1256 case TRACE_SPECIAL:
1257 trace_seq_printf(s, "# %ld %ld %ld\n",
1258 entry->special.arg1,
1259 entry->special.arg2,
1260 entry->special.arg3);
1261 break;
1262 case TRACE_STACK:
1263 for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
1264 if (i)
1265 trace_seq_puts(s, " <= ");
1266 seq_print_ip_sym(s, entry->stack.caller[i], sym_flags);
1267 }
1268 trace_seq_puts(s, "\n");
1269 break;
1270 default:
1271 trace_seq_printf(s, "Unknown type %d\n", entry->type);
1272 }
1273 return 1;
1274 }
1275
1276 static int print_trace_fmt(struct trace_iterator *iter)
1277 {
1278 struct trace_seq *s = &iter->seq;
1279 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1280 struct trace_entry *entry;
1281 unsigned long usec_rem;
1282 unsigned long long t;
1283 unsigned long secs;
1284 char *comm;
1285 int ret;
1286 int S, T;
1287 int i;
1288
1289 entry = iter->ent;
1290
1291 comm = trace_find_cmdline(iter->ent->pid);
1292
1293 t = ns2usecs(entry->t);
1294 usec_rem = do_div(t, 1000000ULL);
1295 secs = (unsigned long)t;
1296
1297 ret = trace_seq_printf(s, "%16s-%-5d ", comm, entry->pid);
1298 if (!ret)
1299 return 0;
1300 ret = trace_seq_printf(s, "[%02d] ", iter->cpu);
1301 if (!ret)
1302 return 0;
1303 ret = trace_seq_printf(s, "%5lu.%06lu: ", secs, usec_rem);
1304 if (!ret)
1305 return 0;
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 T = entry->ctx.next_state < sizeof(state_to_char) ?
1331 state_to_char[entry->ctx.next_state] : 'X';
1332 ret = trace_seq_printf(s, " %5d:%3d:%c %s %5d:%3d:%c\n",
1333 entry->ctx.prev_pid,
1334 entry->ctx.prev_prio,
1335 S,
1336 entry->type == TRACE_CTX ? "==>" : " +",
1337 entry->ctx.next_pid,
1338 entry->ctx.next_prio,
1339 T);
1340 if (!ret)
1341 return 0;
1342 break;
1343 case TRACE_SPECIAL:
1344 ret = trace_seq_printf(s, "# %ld %ld %ld\n",
1345 entry->special.arg1,
1346 entry->special.arg2,
1347 entry->special.arg3);
1348 if (!ret)
1349 return 0;
1350 break;
1351 case TRACE_STACK:
1352 for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
1353 if (i) {
1354 ret = trace_seq_puts(s, " <= ");
1355 if (!ret)
1356 return 0;
1357 }
1358 ret = seq_print_ip_sym(s, entry->stack.caller[i],
1359 sym_flags);
1360 if (!ret)
1361 return 0;
1362 }
1363 ret = trace_seq_puts(s, "\n");
1364 if (!ret)
1365 return 0;
1366 break;
1367 }
1368 return 1;
1369 }
1370
1371 static int print_raw_fmt(struct trace_iterator *iter)
1372 {
1373 struct trace_seq *s = &iter->seq;
1374 struct trace_entry *entry;
1375 int ret;
1376 int S, T;
1377
1378 entry = iter->ent;
1379
1380 ret = trace_seq_printf(s, "%d %d %llu ",
1381 entry->pid, iter->cpu, entry->t);
1382 if (!ret)
1383 return 0;
1384
1385 switch (entry->type) {
1386 case TRACE_FN:
1387 ret = trace_seq_printf(s, "%x %x\n",
1388 entry->fn.ip, entry->fn.parent_ip);
1389 if (!ret)
1390 return 0;
1391 break;
1392 case TRACE_CTX:
1393 case TRACE_WAKE:
1394 S = entry->ctx.prev_state < sizeof(state_to_char) ?
1395 state_to_char[entry->ctx.prev_state] : 'X';
1396 T = entry->ctx.next_state < sizeof(state_to_char) ?
1397 state_to_char[entry->ctx.next_state] : 'X';
1398 if (entry->type == TRACE_WAKE)
1399 S = '+';
1400 ret = trace_seq_printf(s, "%d %d %c %d %d %c\n",
1401 entry->ctx.prev_pid,
1402 entry->ctx.prev_prio,
1403 S,
1404 entry->ctx.next_pid,
1405 entry->ctx.next_prio,
1406 T);
1407 if (!ret)
1408 return 0;
1409 break;
1410 case TRACE_SPECIAL:
1411 case TRACE_STACK:
1412 ret = trace_seq_printf(s, "# %ld %ld %ld\n",
1413 entry->special.arg1,
1414 entry->special.arg2,
1415 entry->special.arg3);
1416 if (!ret)
1417 return 0;
1418 break;
1419 }
1420 return 1;
1421 }
1422
1423 #define SEQ_PUT_FIELD_RET(s, x) \
1424 do { \
1425 if (!trace_seq_putmem(s, &(x), sizeof(x))) \
1426 return 0; \
1427 } while (0)
1428
1429 #define SEQ_PUT_HEX_FIELD_RET(s, x) \
1430 do { \
1431 if (!trace_seq_putmem_hex(s, &(x), sizeof(x))) \
1432 return 0; \
1433 } while (0)
1434
1435 static int print_hex_fmt(struct trace_iterator *iter)
1436 {
1437 struct trace_seq *s = &iter->seq;
1438 unsigned char newline = '\n';
1439 struct trace_entry *entry;
1440 int S, T;
1441
1442 entry = iter->ent;
1443
1444 SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
1445 SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
1446 SEQ_PUT_HEX_FIELD_RET(s, entry->t);
1447
1448 switch (entry->type) {
1449 case TRACE_FN:
1450 SEQ_PUT_HEX_FIELD_RET(s, entry->fn.ip);
1451 SEQ_PUT_HEX_FIELD_RET(s, entry->fn.parent_ip);
1452 break;
1453 case TRACE_CTX:
1454 case TRACE_WAKE:
1455 S = entry->ctx.prev_state < sizeof(state_to_char) ?
1456 state_to_char[entry->ctx.prev_state] : 'X';
1457 T = entry->ctx.next_state < sizeof(state_to_char) ?
1458 state_to_char[entry->ctx.next_state] : 'X';
1459 if (entry->type == TRACE_WAKE)
1460 S = '+';
1461 SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.prev_pid);
1462 SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.prev_prio);
1463 SEQ_PUT_HEX_FIELD_RET(s, S);
1464 SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.next_pid);
1465 SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.next_prio);
1466 SEQ_PUT_HEX_FIELD_RET(s, entry->fn.parent_ip);
1467 SEQ_PUT_HEX_FIELD_RET(s, T);
1468 break;
1469 case TRACE_SPECIAL:
1470 case TRACE_STACK:
1471 SEQ_PUT_HEX_FIELD_RET(s, entry->special.arg1);
1472 SEQ_PUT_HEX_FIELD_RET(s, entry->special.arg2);
1473 SEQ_PUT_HEX_FIELD_RET(s, entry->special.arg3);
1474 break;
1475 }
1476 SEQ_PUT_FIELD_RET(s, newline);
1477
1478 return 1;
1479 }
1480
1481 static int print_bin_fmt(struct trace_iterator *iter)
1482 {
1483 struct trace_seq *s = &iter->seq;
1484 struct trace_entry *entry;
1485
1486 entry = iter->ent;
1487
1488 SEQ_PUT_FIELD_RET(s, entry->pid);
1489 SEQ_PUT_FIELD_RET(s, entry->cpu);
1490 SEQ_PUT_FIELD_RET(s, entry->t);
1491
1492 switch (entry->type) {
1493 case TRACE_FN:
1494 SEQ_PUT_FIELD_RET(s, entry->fn.ip);
1495 SEQ_PUT_FIELD_RET(s, entry->fn.parent_ip);
1496 break;
1497 case TRACE_CTX:
1498 SEQ_PUT_FIELD_RET(s, entry->ctx.prev_pid);
1499 SEQ_PUT_FIELD_RET(s, entry->ctx.prev_prio);
1500 SEQ_PUT_FIELD_RET(s, entry->ctx.prev_state);
1501 SEQ_PUT_FIELD_RET(s, entry->ctx.next_pid);
1502 SEQ_PUT_FIELD_RET(s, entry->ctx.next_prio);
1503 SEQ_PUT_FIELD_RET(s, entry->ctx.next_state);
1504 break;
1505 case TRACE_SPECIAL:
1506 case TRACE_STACK:
1507 SEQ_PUT_FIELD_RET(s, entry->special.arg1);
1508 SEQ_PUT_FIELD_RET(s, entry->special.arg2);
1509 SEQ_PUT_FIELD_RET(s, entry->special.arg3);
1510 break;
1511 }
1512 return 1;
1513 }
1514
1515 static int trace_empty(struct trace_iterator *iter)
1516 {
1517 struct trace_array_cpu *data;
1518 int cpu;
1519
1520 for_each_possible_cpu(cpu) {
1521 data = iter->tr->data[cpu];
1522
1523 if (head_page(data) && data->trace_idx &&
1524 (data->trace_tail != data->trace_head ||
1525 data->trace_tail_idx != data->trace_head_idx))
1526 return 0;
1527 }
1528 return 1;
1529 }
1530
1531 static int print_trace_line(struct trace_iterator *iter)
1532 {
1533 if (trace_flags & TRACE_ITER_BIN)
1534 return print_bin_fmt(iter);
1535
1536 if (trace_flags & TRACE_ITER_HEX)
1537 return print_hex_fmt(iter);
1538
1539 if (trace_flags & TRACE_ITER_RAW)
1540 return print_raw_fmt(iter);
1541
1542 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
1543 return print_lat_fmt(iter, iter->idx, iter->cpu);
1544
1545 return print_trace_fmt(iter);
1546 }
1547
1548 static int s_show(struct seq_file *m, void *v)
1549 {
1550 struct trace_iterator *iter = v;
1551
1552 if (iter->ent == NULL) {
1553 if (iter->tr) {
1554 seq_printf(m, "# tracer: %s\n", iter->trace->name);
1555 seq_puts(m, "#\n");
1556 }
1557 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
1558 /* print nothing if the buffers are empty */
1559 if (trace_empty(iter))
1560 return 0;
1561 print_trace_header(m, iter);
1562 if (!(trace_flags & TRACE_ITER_VERBOSE))
1563 print_lat_help_header(m);
1564 } else {
1565 if (!(trace_flags & TRACE_ITER_VERBOSE))
1566 print_func_help_header(m);
1567 }
1568 } else {
1569 print_trace_line(iter);
1570 trace_print_seq(m, &iter->seq);
1571 }
1572
1573 return 0;
1574 }
1575
1576 static struct seq_operations tracer_seq_ops = {
1577 .start = s_start,
1578 .next = s_next,
1579 .stop = s_stop,
1580 .show = s_show,
1581 };
1582
1583 static struct trace_iterator *
1584 __tracing_open(struct inode *inode, struct file *file, int *ret)
1585 {
1586 struct trace_iterator *iter;
1587
1588 if (tracing_disabled) {
1589 *ret = -ENODEV;
1590 return NULL;
1591 }
1592
1593 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1594 if (!iter) {
1595 *ret = -ENOMEM;
1596 goto out;
1597 }
1598
1599 mutex_lock(&trace_types_lock);
1600 if (current_trace && current_trace->print_max)
1601 iter->tr = &max_tr;
1602 else
1603 iter->tr = inode->i_private;
1604 iter->trace = current_trace;
1605 iter->pos = -1;
1606
1607 /* TODO stop tracer */
1608 *ret = seq_open(file, &tracer_seq_ops);
1609 if (!*ret) {
1610 struct seq_file *m = file->private_data;
1611 m->private = iter;
1612
1613 /* stop the trace while dumping */
1614 if (iter->tr->ctrl)
1615 tracer_enabled = 0;
1616
1617 if (iter->trace && iter->trace->open)
1618 iter->trace->open(iter);
1619 } else {
1620 kfree(iter);
1621 iter = NULL;
1622 }
1623 mutex_unlock(&trace_types_lock);
1624
1625 out:
1626 return iter;
1627 }
1628
1629 int tracing_open_generic(struct inode *inode, struct file *filp)
1630 {
1631 if (tracing_disabled)
1632 return -ENODEV;
1633
1634 filp->private_data = inode->i_private;
1635 return 0;
1636 }
1637
1638 int tracing_release(struct inode *inode, struct file *file)
1639 {
1640 struct seq_file *m = (struct seq_file *)file->private_data;
1641 struct trace_iterator *iter = m->private;
1642
1643 mutex_lock(&trace_types_lock);
1644 if (iter->trace && iter->trace->close)
1645 iter->trace->close(iter);
1646
1647 /* reenable tracing if it was previously enabled */
1648 if (iter->tr->ctrl)
1649 tracer_enabled = 1;
1650 mutex_unlock(&trace_types_lock);
1651
1652 seq_release(inode, file);
1653 kfree(iter);
1654 return 0;
1655 }
1656
1657 static int tracing_open(struct inode *inode, struct file *file)
1658 {
1659 int ret;
1660
1661 __tracing_open(inode, file, &ret);
1662
1663 return ret;
1664 }
1665
1666 static int tracing_lt_open(struct inode *inode, struct file *file)
1667 {
1668 struct trace_iterator *iter;
1669 int ret;
1670
1671 iter = __tracing_open(inode, file, &ret);
1672
1673 if (!ret)
1674 iter->iter_flags |= TRACE_FILE_LAT_FMT;
1675
1676 return ret;
1677 }
1678
1679
1680 static void *
1681 t_next(struct seq_file *m, void *v, loff_t *pos)
1682 {
1683 struct tracer *t = m->private;
1684
1685 (*pos)++;
1686
1687 if (t)
1688 t = t->next;
1689
1690 m->private = t;
1691
1692 return t;
1693 }
1694
1695 static void *t_start(struct seq_file *m, loff_t *pos)
1696 {
1697 struct tracer *t = m->private;
1698 loff_t l = 0;
1699
1700 mutex_lock(&trace_types_lock);
1701 for (; t && l < *pos; t = t_next(m, t, &l))
1702 ;
1703
1704 return t;
1705 }
1706
1707 static void t_stop(struct seq_file *m, void *p)
1708 {
1709 mutex_unlock(&trace_types_lock);
1710 }
1711
1712 static int t_show(struct seq_file *m, void *v)
1713 {
1714 struct tracer *t = v;
1715
1716 if (!t)
1717 return 0;
1718
1719 seq_printf(m, "%s", t->name);
1720 if (t->next)
1721 seq_putc(m, ' ');
1722 else
1723 seq_putc(m, '\n');
1724
1725 return 0;
1726 }
1727
1728 static struct seq_operations show_traces_seq_ops = {
1729 .start = t_start,
1730 .next = t_next,
1731 .stop = t_stop,
1732 .show = t_show,
1733 };
1734
1735 static int show_traces_open(struct inode *inode, struct file *file)
1736 {
1737 int ret;
1738
1739 if (tracing_disabled)
1740 return -ENODEV;
1741
1742 ret = seq_open(file, &show_traces_seq_ops);
1743 if (!ret) {
1744 struct seq_file *m = file->private_data;
1745 m->private = trace_types;
1746 }
1747
1748 return ret;
1749 }
1750
1751 static struct file_operations tracing_fops = {
1752 .open = tracing_open,
1753 .read = seq_read,
1754 .llseek = seq_lseek,
1755 .release = tracing_release,
1756 };
1757
1758 static struct file_operations tracing_lt_fops = {
1759 .open = tracing_lt_open,
1760 .read = seq_read,
1761 .llseek = seq_lseek,
1762 .release = tracing_release,
1763 };
1764
1765 static struct file_operations show_traces_fops = {
1766 .open = show_traces_open,
1767 .read = seq_read,
1768 .release = seq_release,
1769 };
1770
1771 /*
1772 * Only trace on a CPU if the bitmask is set:
1773 */
1774 static cpumask_t tracing_cpumask = CPU_MASK_ALL;
1775
1776 /*
1777 * When tracing/tracing_cpu_mask is modified then this holds
1778 * the new bitmask we are about to install:
1779 */
1780 static cpumask_t tracing_cpumask_new;
1781
1782 /*
1783 * The tracer itself will not take this lock, but still we want
1784 * to provide a consistent cpumask to user-space:
1785 */
1786 static DEFINE_MUTEX(tracing_cpumask_update_lock);
1787
1788 /*
1789 * Temporary storage for the character representation of the
1790 * CPU bitmask (and one more byte for the newline):
1791 */
1792 static char mask_str[NR_CPUS + 1];
1793
1794 static ssize_t
1795 tracing_cpumask_read(struct file *filp, char __user *ubuf,
1796 size_t count, loff_t *ppos)
1797 {
1798 int len;
1799
1800 mutex_lock(&tracing_cpumask_update_lock);
1801
1802 len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
1803 if (count - len < 2) {
1804 count = -EINVAL;
1805 goto out_err;
1806 }
1807 len += sprintf(mask_str + len, "\n");
1808 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
1809
1810 out_err:
1811 mutex_unlock(&tracing_cpumask_update_lock);
1812
1813 return count;
1814 }
1815
1816 static ssize_t
1817 tracing_cpumask_write(struct file *filp, const char __user *ubuf,
1818 size_t count, loff_t *ppos)
1819 {
1820 int err, cpu;
1821
1822 mutex_lock(&tracing_cpumask_update_lock);
1823 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
1824 if (err)
1825 goto err_unlock;
1826
1827 spin_lock_irq(&ftrace_max_lock);
1828 for_each_possible_cpu(cpu) {
1829 /*
1830 * Increase/decrease the disabled counter if we are
1831 * about to flip a bit in the cpumask:
1832 */
1833 if (cpu_isset(cpu, tracing_cpumask) &&
1834 !cpu_isset(cpu, tracing_cpumask_new)) {
1835 atomic_inc(&global_trace.data[cpu]->disabled);
1836 }
1837 if (!cpu_isset(cpu, tracing_cpumask) &&
1838 cpu_isset(cpu, tracing_cpumask_new)) {
1839 atomic_dec(&global_trace.data[cpu]->disabled);
1840 }
1841 }
1842 spin_unlock_irq(&ftrace_max_lock);
1843
1844 tracing_cpumask = tracing_cpumask_new;
1845
1846 mutex_unlock(&tracing_cpumask_update_lock);
1847
1848 return count;
1849
1850 err_unlock:
1851 mutex_unlock(&tracing_cpumask_update_lock);
1852
1853 return err;
1854 }
1855
1856 static struct file_operations tracing_cpumask_fops = {
1857 .open = tracing_open_generic,
1858 .read = tracing_cpumask_read,
1859 .write = tracing_cpumask_write,
1860 };
1861
1862 static ssize_t
1863 tracing_iter_ctrl_read(struct file *filp, char __user *ubuf,
1864 size_t cnt, loff_t *ppos)
1865 {
1866 char *buf;
1867 int r = 0;
1868 int len = 0;
1869 int i;
1870
1871 /* calulate max size */
1872 for (i = 0; trace_options[i]; i++) {
1873 len += strlen(trace_options[i]);
1874 len += 3; /* "no" and space */
1875 }
1876
1877 /* +2 for \n and \0 */
1878 buf = kmalloc(len + 2, GFP_KERNEL);
1879 if (!buf)
1880 return -ENOMEM;
1881
1882 for (i = 0; trace_options[i]; i++) {
1883 if (trace_flags & (1 << i))
1884 r += sprintf(buf + r, "%s ", trace_options[i]);
1885 else
1886 r += sprintf(buf + r, "no%s ", trace_options[i]);
1887 }
1888
1889 r += sprintf(buf + r, "\n");
1890 WARN_ON(r >= len + 2);
1891
1892 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1893
1894 kfree(buf);
1895
1896 return r;
1897 }
1898
1899 static ssize_t
1900 tracing_iter_ctrl_write(struct file *filp, const char __user *ubuf,
1901 size_t cnt, loff_t *ppos)
1902 {
1903 char buf[64];
1904 char *cmp = buf;
1905 int neg = 0;
1906 int i;
1907
1908 if (cnt > 63)
1909 cnt = 63;
1910
1911 if (copy_from_user(&buf, ubuf, cnt))
1912 return -EFAULT;
1913
1914 buf[cnt] = 0;
1915
1916 if (strncmp(buf, "no", 2) == 0) {
1917 neg = 1;
1918 cmp += 2;
1919 }
1920
1921 for (i = 0; trace_options[i]; i++) {
1922 int len = strlen(trace_options[i]);
1923
1924 if (strncmp(cmp, trace_options[i], len) == 0) {
1925 if (neg)
1926 trace_flags &= ~(1 << i);
1927 else
1928 trace_flags |= (1 << i);
1929 break;
1930 }
1931 }
1932 /*
1933 * If no option could be set, return an error:
1934 */
1935 if (!trace_options[i])
1936 return -EINVAL;
1937
1938 filp->f_pos += cnt;
1939
1940 return cnt;
1941 }
1942
1943 static struct file_operations tracing_iter_fops = {
1944 .open = tracing_open_generic,
1945 .read = tracing_iter_ctrl_read,
1946 .write = tracing_iter_ctrl_write,
1947 };
1948
1949 static const char readme_msg[] =
1950 "tracing mini-HOWTO:\n\n"
1951 "# mkdir /debug\n"
1952 "# mount -t debugfs nodev /debug\n\n"
1953 "# cat /debug/tracing/available_tracers\n"
1954 "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
1955 "# cat /debug/tracing/current_tracer\n"
1956 "none\n"
1957 "# echo sched_switch > /debug/tracing/current_tracer\n"
1958 "# cat /debug/tracing/current_tracer\n"
1959 "sched_switch\n"
1960 "# cat /debug/tracing/iter_ctrl\n"
1961 "noprint-parent nosym-offset nosym-addr noverbose\n"
1962 "# echo print-parent > /debug/tracing/iter_ctrl\n"
1963 "# echo 1 > /debug/tracing/tracing_enabled\n"
1964 "# cat /debug/tracing/trace > /tmp/trace.txt\n"
1965 "echo 0 > /debug/tracing/tracing_enabled\n"
1966 ;
1967
1968 static ssize_t
1969 tracing_readme_read(struct file *filp, char __user *ubuf,
1970 size_t cnt, loff_t *ppos)
1971 {
1972 return simple_read_from_buffer(ubuf, cnt, ppos,
1973 readme_msg, strlen(readme_msg));
1974 }
1975
1976 static struct file_operations tracing_readme_fops = {
1977 .open = tracing_open_generic,
1978 .read = tracing_readme_read,
1979 };
1980
1981 static ssize_t
1982 tracing_ctrl_read(struct file *filp, char __user *ubuf,
1983 size_t cnt, loff_t *ppos)
1984 {
1985 struct trace_array *tr = filp->private_data;
1986 char buf[64];
1987 int r;
1988
1989 r = sprintf(buf, "%ld\n", tr->ctrl);
1990 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1991 }
1992
1993 static ssize_t
1994 tracing_ctrl_write(struct file *filp, const char __user *ubuf,
1995 size_t cnt, loff_t *ppos)
1996 {
1997 struct trace_array *tr = filp->private_data;
1998 long val;
1999 char buf[64];
2000
2001 if (cnt > 63)
2002 cnt = 63;
2003
2004 if (copy_from_user(&buf, ubuf, cnt))
2005 return -EFAULT;
2006
2007 buf[cnt] = 0;
2008
2009 val = simple_strtoul(buf, NULL, 10);
2010
2011 val = !!val;
2012
2013 mutex_lock(&trace_types_lock);
2014 if (tr->ctrl ^ val) {
2015 if (val)
2016 tracer_enabled = 1;
2017 else
2018 tracer_enabled = 0;
2019
2020 tr->ctrl = val;
2021
2022 if (current_trace && current_trace->ctrl_update)
2023 current_trace->ctrl_update(tr);
2024 }
2025 mutex_unlock(&trace_types_lock);
2026
2027 filp->f_pos += cnt;
2028
2029 return cnt;
2030 }
2031
2032 static ssize_t
2033 tracing_set_trace_read(struct file *filp, char __user *ubuf,
2034 size_t cnt, loff_t *ppos)
2035 {
2036 char buf[max_tracer_type_len+2];
2037 int r;
2038
2039 mutex_lock(&trace_types_lock);
2040 if (current_trace)
2041 r = sprintf(buf, "%s\n", current_trace->name);
2042 else
2043 r = sprintf(buf, "\n");
2044 mutex_unlock(&trace_types_lock);
2045
2046 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2047 }
2048
2049 static ssize_t
2050 tracing_set_trace_write(struct file *filp, const char __user *ubuf,
2051 size_t cnt, loff_t *ppos)
2052 {
2053 struct trace_array *tr = &global_trace;
2054 struct tracer *t;
2055 char buf[max_tracer_type_len+1];
2056 int i;
2057
2058 if (cnt > max_tracer_type_len)
2059 cnt = max_tracer_type_len;
2060
2061 if (copy_from_user(&buf, ubuf, cnt))
2062 return -EFAULT;
2063
2064 buf[cnt] = 0;
2065
2066 /* strip ending whitespace. */
2067 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
2068 buf[i] = 0;
2069
2070 mutex_lock(&trace_types_lock);
2071 for (t = trace_types; t; t = t->next) {
2072 if (strcmp(t->name, buf) == 0)
2073 break;
2074 }
2075 if (!t || t == current_trace)
2076 goto out;
2077
2078 if (current_trace && current_trace->reset)
2079 current_trace->reset(tr);
2080
2081 current_trace = t;
2082 if (t->init)
2083 t->init(tr);
2084
2085 out:
2086 mutex_unlock(&trace_types_lock);
2087
2088 filp->f_pos += cnt;
2089
2090 return cnt;
2091 }
2092
2093 static ssize_t
2094 tracing_max_lat_read(struct file *filp, char __user *ubuf,
2095 size_t cnt, loff_t *ppos)
2096 {
2097 unsigned long *ptr = filp->private_data;
2098 char buf[64];
2099 int r;
2100
2101 r = snprintf(buf, 64, "%ld\n",
2102 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
2103 if (r > 64)
2104 r = 64;
2105 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2106 }
2107
2108 static ssize_t
2109 tracing_max_lat_write(struct file *filp, const char __user *ubuf,
2110 size_t cnt, loff_t *ppos)
2111 {
2112 long *ptr = filp->private_data;
2113 long val;
2114 char buf[64];
2115
2116 if (cnt > 63)
2117 cnt = 63;
2118
2119 if (copy_from_user(&buf, ubuf, cnt))
2120 return -EFAULT;
2121
2122 buf[cnt] = 0;
2123
2124 val = simple_strtoul(buf, NULL, 10);
2125
2126 *ptr = val * 1000;
2127
2128 return cnt;
2129 }
2130
2131 static atomic_t tracing_reader;
2132
2133 static int tracing_open_pipe(struct inode *inode, struct file *filp)
2134 {
2135 struct trace_iterator *iter;
2136
2137 if (tracing_disabled)
2138 return -ENODEV;
2139
2140 /* We only allow for reader of the pipe */
2141 if (atomic_inc_return(&tracing_reader) != 1) {
2142 atomic_dec(&tracing_reader);
2143 return -EBUSY;
2144 }
2145
2146 /* create a buffer to store the information to pass to userspace */
2147 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2148 if (!iter)
2149 return -ENOMEM;
2150
2151 iter->tr = &global_trace;
2152
2153 filp->private_data = iter;
2154
2155 return 0;
2156 }
2157
2158 static int tracing_release_pipe(struct inode *inode, struct file *file)
2159 {
2160 struct trace_iterator *iter = file->private_data;
2161
2162 kfree(iter);
2163 atomic_dec(&tracing_reader);
2164
2165 return 0;
2166 }
2167
2168 static unsigned int
2169 tracing_poll_pipe(struct file *filp, poll_table *poll_table)
2170 {
2171 struct trace_iterator *iter = filp->private_data;
2172
2173 if (trace_flags & TRACE_ITER_BLOCK) {
2174 /*
2175 * Always select as readable when in blocking mode
2176 */
2177 return POLLIN | POLLRDNORM;
2178 }
2179 else {
2180 if (!trace_empty(iter))
2181 return POLLIN | POLLRDNORM;
2182 poll_wait(filp, &trace_wait, poll_table);
2183 if (!trace_empty(iter))
2184 return POLLIN | POLLRDNORM;
2185
2186 return 0;
2187 }
2188 }
2189
2190 /*
2191 * Consumer reader.
2192 */
2193 static ssize_t
2194 tracing_read_pipe(struct file *filp, char __user *ubuf,
2195 size_t cnt, loff_t *ppos)
2196 {
2197 struct trace_iterator *iter = filp->private_data;
2198 struct trace_array_cpu *data;
2199 static cpumask_t mask;
2200 static int start;
2201 unsigned long flags;
2202 #ifdef CONFIG_FTRACE
2203 int ftrace_save;
2204 #endif
2205 int read = 0;
2206 int cpu;
2207 int len;
2208 int ret;
2209
2210 /* return any leftover data */
2211 if (iter->seq.len > start) {
2212 len = iter->seq.len - start;
2213 if (cnt > len)
2214 cnt = len;
2215 ret = copy_to_user(ubuf, iter->seq.buffer + start, cnt);
2216 if (ret)
2217 cnt = -EFAULT;
2218
2219 start += len;
2220
2221 return cnt;
2222 }
2223
2224 trace_seq_reset(&iter->seq);
2225 start = 0;
2226
2227 while (trace_empty(iter)) {
2228 if (!(trace_flags & TRACE_ITER_BLOCK))
2229 return -EWOULDBLOCK;
2230 /*
2231 * This is a make-shift waitqueue. The reason we don't use
2232 * an actual wait queue is because:
2233 * 1) we only ever have one waiter
2234 * 2) the tracing, traces all functions, we don't want
2235 * the overhead of calling wake_up and friends
2236 * (and tracing them too)
2237 * Anyway, this is really very primitive wakeup.
2238 */
2239 set_current_state(TASK_INTERRUPTIBLE);
2240 iter->tr->waiter = current;
2241
2242 /* sleep for one second, and try again. */
2243 schedule_timeout(HZ);
2244
2245 iter->tr->waiter = NULL;
2246
2247 if (signal_pending(current))
2248 return -EINTR;
2249
2250 /*
2251 * We block until we read something and tracing is disabled.
2252 * We still block if tracing is disabled, but we have never
2253 * read anything. This allows a user to cat this file, and
2254 * then enable tracing. But after we have read something,
2255 * we give an EOF when tracing is again disabled.
2256 *
2257 * iter->pos will be 0 if we haven't read anything.
2258 */
2259 if (!tracer_enabled && iter->pos)
2260 break;
2261
2262 continue;
2263 }
2264
2265 /* stop when tracing is finished */
2266 if (trace_empty(iter))
2267 return 0;
2268
2269 if (cnt >= PAGE_SIZE)
2270 cnt = PAGE_SIZE - 1;
2271
2272 memset(iter, 0, sizeof(*iter));
2273 iter->tr = &global_trace;
2274 iter->pos = -1;
2275
2276 /*
2277 * We need to stop all tracing on all CPUS to read the
2278 * the next buffer. This is a bit expensive, but is
2279 * not done often. We fill all what we can read,
2280 * and then release the locks again.
2281 */
2282
2283 cpus_clear(mask);
2284 local_irq_save(flags);
2285 #ifdef CONFIG_FTRACE
2286 ftrace_save = ftrace_enabled;
2287 ftrace_enabled = 0;
2288 #endif
2289 smp_wmb();
2290 for_each_possible_cpu(cpu) {
2291 data = iter->tr->data[cpu];
2292
2293 if (!head_page(data) || !data->trace_idx)
2294 continue;
2295
2296 atomic_inc(&data->disabled);
2297 cpu_set(cpu, mask);
2298 }
2299
2300 for_each_cpu_mask(cpu, mask) {
2301 data = iter->tr->data[cpu];
2302 spin_lock(&data->lock);
2303 }
2304
2305 while (find_next_entry_inc(iter) != NULL) {
2306 int len = iter->seq.len;
2307
2308 ret = print_trace_line(iter);
2309 if (!ret) {
2310 /* don't print partial lines */
2311 iter->seq.len = len;
2312 break;
2313 }
2314
2315 trace_consume(iter);
2316
2317 if (iter->seq.len >= cnt)
2318 break;
2319 }
2320
2321 for_each_cpu_mask(cpu, mask) {
2322 data = iter->tr->data[cpu];
2323 spin_unlock(&data->lock);
2324 }
2325
2326 for_each_cpu_mask(cpu, mask) {
2327 data = iter->tr->data[cpu];
2328 atomic_dec(&data->disabled);
2329 }
2330 #ifdef CONFIG_FTRACE
2331 ftrace_enabled = ftrace_save;
2332 #endif
2333 local_irq_restore(flags);
2334
2335 /* Now copy what we have to the user */
2336 read = iter->seq.len;
2337 if (read > cnt)
2338 read = cnt;
2339
2340 ret = copy_to_user(ubuf, iter->seq.buffer, read);
2341
2342 if (read < iter->seq.len)
2343 start = read;
2344 else
2345 trace_seq_reset(&iter->seq);
2346
2347 if (ret)
2348 read = -EFAULT;
2349
2350 return read;
2351 }
2352
2353 static struct file_operations tracing_max_lat_fops = {
2354 .open = tracing_open_generic,
2355 .read = tracing_max_lat_read,
2356 .write = tracing_max_lat_write,
2357 };
2358
2359 static struct file_operations tracing_ctrl_fops = {
2360 .open = tracing_open_generic,
2361 .read = tracing_ctrl_read,
2362 .write = tracing_ctrl_write,
2363 };
2364
2365 static struct file_operations set_tracer_fops = {
2366 .open = tracing_open_generic,
2367 .read = tracing_set_trace_read,
2368 .write = tracing_set_trace_write,
2369 };
2370
2371 static struct file_operations tracing_pipe_fops = {
2372 .open = tracing_open_pipe,
2373 .poll = tracing_poll_pipe,
2374 .read = tracing_read_pipe,
2375 .release = tracing_release_pipe,
2376 };
2377
2378 #ifdef CONFIG_DYNAMIC_FTRACE
2379
2380 static ssize_t
2381 tracing_read_long(struct file *filp, char __user *ubuf,
2382 size_t cnt, loff_t *ppos)
2383 {
2384 unsigned long *p = filp->private_data;
2385 char buf[64];
2386 int r;
2387
2388 r = sprintf(buf, "%ld\n", *p);
2389
2390 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2391 }
2392
2393 static struct file_operations tracing_read_long_fops = {
2394 .open = tracing_open_generic,
2395 .read = tracing_read_long,
2396 };
2397 #endif
2398
2399 static struct dentry *d_tracer;
2400
2401 struct dentry *tracing_init_dentry(void)
2402 {
2403 static int once;
2404
2405 if (d_tracer)
2406 return d_tracer;
2407
2408 d_tracer = debugfs_create_dir("tracing", NULL);
2409
2410 if (!d_tracer && !once) {
2411 once = 1;
2412 pr_warning("Could not create debugfs directory 'tracing'\n");
2413 return NULL;
2414 }
2415
2416 return d_tracer;
2417 }
2418
2419 #ifdef CONFIG_FTRACE_SELFTEST
2420 /* Let selftest have access to static functions in this file */
2421 #include "trace_selftest.c"
2422 #endif
2423
2424 static __init void tracer_init_debugfs(void)
2425 {
2426 struct dentry *d_tracer;
2427 struct dentry *entry;
2428
2429 d_tracer = tracing_init_dentry();
2430
2431 entry = debugfs_create_file("tracing_enabled", 0644, d_tracer,
2432 &global_trace, &tracing_ctrl_fops);
2433 if (!entry)
2434 pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
2435
2436 entry = debugfs_create_file("iter_ctrl", 0644, d_tracer,
2437 NULL, &tracing_iter_fops);
2438 if (!entry)
2439 pr_warning("Could not create debugfs 'iter_ctrl' entry\n");
2440
2441 entry = debugfs_create_file("tracing_cpumask", 0644, d_tracer,
2442 NULL, &tracing_cpumask_fops);
2443 if (!entry)
2444 pr_warning("Could not create debugfs 'tracing_cpumask' entry\n");
2445
2446 entry = debugfs_create_file("latency_trace", 0444, d_tracer,
2447 &global_trace, &tracing_lt_fops);
2448 if (!entry)
2449 pr_warning("Could not create debugfs 'latency_trace' entry\n");
2450
2451 entry = debugfs_create_file("trace", 0444, d_tracer,
2452 &global_trace, &tracing_fops);
2453 if (!entry)
2454 pr_warning("Could not create debugfs 'trace' entry\n");
2455
2456 entry = debugfs_create_file("available_tracers", 0444, d_tracer,
2457 &global_trace, &show_traces_fops);
2458 if (!entry)
2459 pr_warning("Could not create debugfs 'trace' entry\n");
2460
2461 entry = debugfs_create_file("current_tracer", 0444, d_tracer,
2462 &global_trace, &set_tracer_fops);
2463 if (!entry)
2464 pr_warning("Could not create debugfs 'trace' entry\n");
2465
2466 entry = debugfs_create_file("tracing_max_latency", 0644, d_tracer,
2467 &tracing_max_latency,
2468 &tracing_max_lat_fops);
2469 if (!entry)
2470 pr_warning("Could not create debugfs "
2471 "'tracing_max_latency' entry\n");
2472
2473 entry = debugfs_create_file("tracing_thresh", 0644, d_tracer,
2474 &tracing_thresh, &tracing_max_lat_fops);
2475 if (!entry)
2476 pr_warning("Could not create debugfs "
2477 "'tracing_threash' entry\n");
2478 entry = debugfs_create_file("README", 0644, d_tracer,
2479 NULL, &tracing_readme_fops);
2480 if (!entry)
2481 pr_warning("Could not create debugfs 'README' entry\n");
2482
2483 entry = debugfs_create_file("trace_pipe", 0644, d_tracer,
2484 NULL, &tracing_pipe_fops);
2485 if (!entry)
2486 pr_warning("Could not create debugfs "
2487 "'tracing_threash' entry\n");
2488
2489 #ifdef CONFIG_DYNAMIC_FTRACE
2490 entry = debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer,
2491 &ftrace_update_tot_cnt,
2492 &tracing_read_long_fops);
2493 if (!entry)
2494 pr_warning("Could not create debugfs "
2495 "'dyn_ftrace_total_info' entry\n");
2496 #endif
2497 }
2498
2499 /* dummy trace to disable tracing */
2500 static struct tracer no_tracer __read_mostly =
2501 {
2502 .name = "none",
2503 };
2504
2505 static int trace_alloc_page(void)
2506 {
2507 struct trace_array_cpu *data;
2508 struct page *page, *tmp;
2509 LIST_HEAD(pages);
2510 void *array;
2511 int i;
2512
2513 /* first allocate a page for each CPU */
2514 for_each_possible_cpu(i) {
2515 array = (void *)__get_free_page(GFP_KERNEL);
2516 if (array == NULL) {
2517 printk(KERN_ERR "tracer: failed to allocate page"
2518 "for trace buffer!\n");
2519 goto free_pages;
2520 }
2521
2522 page = virt_to_page(array);
2523 list_add(&page->lru, &pages);
2524
2525 /* Only allocate if we are actually using the max trace */
2526 #ifdef CONFIG_TRACER_MAX_TRACE
2527 array = (void *)__get_free_page(GFP_KERNEL);
2528 if (array == NULL) {
2529 printk(KERN_ERR "tracer: failed to allocate page"
2530 "for trace buffer!\n");
2531 goto free_pages;
2532 }
2533 page = virt_to_page(array);
2534 list_add(&page->lru, &pages);
2535 #endif
2536 }
2537
2538 /* Now that we successfully allocate a page per CPU, add them */
2539 for_each_possible_cpu(i) {
2540 data = global_trace.data[i];
2541 spin_lock_init(&data->lock);
2542 lockdep_set_class(&data->lock, &data->lock_key);
2543 page = list_entry(pages.next, struct page, lru);
2544 list_del_init(&page->lru);
2545 list_add_tail(&page->lru, &data->trace_pages);
2546 ClearPageLRU(page);
2547
2548 #ifdef CONFIG_TRACER_MAX_TRACE
2549 data = max_tr.data[i];
2550 spin_lock_init(&data->lock);
2551 lockdep_set_class(&data->lock, &data->lock_key);
2552 page = list_entry(pages.next, struct page, lru);
2553 list_del_init(&page->lru);
2554 list_add_tail(&page->lru, &data->trace_pages);
2555 SetPageLRU(page);
2556 #endif
2557 }
2558 global_trace.entries += ENTRIES_PER_PAGE;
2559
2560 return 0;
2561
2562 free_pages:
2563 list_for_each_entry_safe(page, tmp, &pages, lru) {
2564 list_del_init(&page->lru);
2565 __free_page(page);
2566 }
2567 return -ENOMEM;
2568 }
2569
2570 __init static int tracer_alloc_buffers(void)
2571 {
2572 struct trace_array_cpu *data;
2573 void *array;
2574 struct page *page;
2575 int pages = 0;
2576 int ret = -ENOMEM;
2577 int i;
2578
2579 global_trace.ctrl = tracer_enabled;
2580
2581 /* Allocate the first page for all buffers */
2582 for_each_possible_cpu(i) {
2583 data = global_trace.data[i] = &per_cpu(global_trace_cpu, i);
2584 max_tr.data[i] = &per_cpu(max_data, i);
2585
2586 array = (void *)__get_free_page(GFP_KERNEL);
2587 if (array == NULL) {
2588 printk(KERN_ERR "tracer: failed to allocate page"
2589 "for trace buffer!\n");
2590 goto free_buffers;
2591 }
2592
2593 /* set the array to the list */
2594 INIT_LIST_HEAD(&data->trace_pages);
2595 page = virt_to_page(array);
2596 list_add(&page->lru, &data->trace_pages);
2597 /* use the LRU flag to differentiate the two buffers */
2598 ClearPageLRU(page);
2599
2600 /* Only allocate if we are actually using the max trace */
2601 #ifdef CONFIG_TRACER_MAX_TRACE
2602 array = (void *)__get_free_page(GFP_KERNEL);
2603 if (array == NULL) {
2604 printk(KERN_ERR "tracer: failed to allocate page"
2605 "for trace buffer!\n");
2606 goto free_buffers;
2607 }
2608
2609 INIT_LIST_HEAD(&max_tr.data[i]->trace_pages);
2610 page = virt_to_page(array);
2611 list_add(&page->lru, &max_tr.data[i]->trace_pages);
2612 SetPageLRU(page);
2613 #endif
2614 }
2615
2616 /*
2617 * Since we allocate by orders of pages, we may be able to
2618 * round up a bit.
2619 */
2620 global_trace.entries = ENTRIES_PER_PAGE;
2621 pages++;
2622
2623 while (global_trace.entries < trace_nr_entries) {
2624 if (trace_alloc_page())
2625 break;
2626 pages++;
2627 }
2628 max_tr.entries = global_trace.entries;
2629
2630 pr_info("tracer: %d pages allocated for %ld",
2631 pages, trace_nr_entries);
2632 pr_info(" entries of %ld bytes\n", (long)TRACE_ENTRY_SIZE);
2633 pr_info(" actual entries %ld\n", global_trace.entries);
2634
2635 tracer_init_debugfs();
2636
2637 trace_init_cmdlines();
2638
2639 register_tracer(&no_tracer);
2640 current_trace = &no_tracer;
2641
2642 /* All seems OK, enable tracing */
2643 tracing_disabled = 0;
2644
2645 return 0;
2646
2647 free_buffers:
2648 for (i-- ; i >= 0; i--) {
2649 struct page *page, *tmp;
2650 struct trace_array_cpu *data = global_trace.data[i];
2651
2652 if (data) {
2653 list_for_each_entry_safe(page, tmp,
2654 &data->trace_pages, lru) {
2655 list_del_init(&page->lru);
2656 __free_page(page);
2657 }
2658 }
2659
2660 #ifdef CONFIG_TRACER_MAX_TRACE
2661 data = max_tr.data[i];
2662 if (data) {
2663 list_for_each_entry_safe(page, tmp,
2664 &data->trace_pages, lru) {
2665 list_del_init(&page->lru);
2666 __free_page(page);
2667 }
2668 }
2669 #endif
2670 }
2671 return ret;
2672 }
2673 fs_initcall(tracer_alloc_buffers);
Linux kernel - Deliverables
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