?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
ftrace: insert in the ftrace_preempt_disable()/enable() functions
[linux-2.6.git] / kernel / trace / trace.c
blob3e7bf5eb9007e7acf139a89107dd52fc6acbec7a
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/notifier.h>
18 #include <linux/debugfs.h>
19 #include <linux/pagemap.h>
20 #include <linux/hardirq.h>
21 #include <linux/linkage.h>
22 #include <linux/uaccess.h>
23 #include <linux/ftrace.h>
24 #include <linux/module.h>
25 #include <linux/percpu.h>
26 #include <linux/kdebug.h>
27 #include <linux/ctype.h>
28 #include <linux/init.h>
29 #include <linux/poll.h>
30 #include <linux/gfp.h>
31 #include <linux/fs.h>
32 #include <linux/kprobes.h>
33 #include <linux/writeback.h>
34
35 #include <linux/stacktrace.h>
36 #include <linux/ring_buffer.h>
37 #include <linux/irqflags.h>
38
39 #include "trace.h"
40
41 #define TRACE_BUFFER_FLAGS (RB_FL_OVERWRITE)
42
43 unsigned long __read_mostly tracing_max_latency = (cycle_t)ULONG_MAX;
44 unsigned long __read_mostly tracing_thresh;
45
46 static DEFINE_PER_CPU(local_t, ftrace_cpu_disabled);
47
48 static inline void ftrace_disable_cpu(void)
49 {
50 preempt_disable();
51 local_inc(&__get_cpu_var(ftrace_cpu_disabled));
52 }
53
54 static inline void ftrace_enable_cpu(void)
55 {
56 local_dec(&__get_cpu_var(ftrace_cpu_disabled));
57 preempt_enable();
58 }
59
60 static cpumask_t __read_mostly tracing_buffer_mask;
61
62 #define for_each_tracing_cpu(cpu) \
63 for_each_cpu_mask(cpu, tracing_buffer_mask)
64
65 static int tracing_disabled = 1;
66
67 /*
68 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
69 *
70 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
71 * is set, then ftrace_dump is called. This will output the contents
72 * of the ftrace buffers to the console. This is very useful for
73 * capturing traces that lead to crashes and outputing it to a
74 * serial console.
75 *
76 * It is default off, but you can enable it with either specifying
77 * "ftrace_dump_on_oops" in the kernel command line, or setting
78 * /proc/sys/kernel/ftrace_dump_on_oops to true.
79 */
80 int ftrace_dump_on_oops;
81
82 static int tracing_set_tracer(char *buf);
83
84 static int __init set_ftrace(char *str)
85 {
86 tracing_set_tracer(str);
87 return 1;
88 }
89 __setup("ftrace", set_ftrace);
90
91 static int __init set_ftrace_dump_on_oops(char *str)
92 {
93 ftrace_dump_on_oops = 1;
94 return 1;
95 }
96 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
97
98 long
99 ns2usecs(cycle_t nsec)
100 {
101 nsec += 500;
102 do_div(nsec, 1000);
103 return nsec;
104 }
105
106 cycle_t ftrace_now(int cpu)
107 {
108 u64 ts = ring_buffer_time_stamp(cpu);
109 ring_buffer_normalize_time_stamp(cpu, &ts);
110 return ts;
111 }
112
113 /*
114 * The global_trace is the descriptor that holds the tracing
115 * buffers for the live tracing. For each CPU, it contains
116 * a link list of pages that will store trace entries. The
117 * page descriptor of the pages in the memory is used to hold
118 * the link list by linking the lru item in the page descriptor
119 * to each of the pages in the buffer per CPU.
120 *
121 * For each active CPU there is a data field that holds the
122 * pages for the buffer for that CPU. Each CPU has the same number
123 * of pages allocated for its buffer.
124 */
125 static struct trace_array global_trace;
126
127 static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
128
129 /*
130 * The max_tr is used to snapshot the global_trace when a maximum
131 * latency is reached. Some tracers will use this to store a maximum
132 * trace while it continues examining live traces.
133 *
134 * The buffers for the max_tr are set up the same as the global_trace.
135 * When a snapshot is taken, the link list of the max_tr is swapped
136 * with the link list of the global_trace and the buffers are reset for
137 * the global_trace so the tracing can continue.
138 */
139 static struct trace_array max_tr;
140
141 static DEFINE_PER_CPU(struct trace_array_cpu, max_data);
142
143 /* tracer_enabled is used to toggle activation of a tracer */
144 static int tracer_enabled = 1;
145
146 /* function tracing enabled */
147 int ftrace_function_enabled;
148
149 /*
150 * trace_buf_size is the size in bytes that is allocated
151 * for a buffer. Note, the number of bytes is always rounded
152 * to page size.
153 *
154 * This number is purposely set to a low number of 16384.
155 * If the dump on oops happens, it will be much appreciated
156 * to not have to wait for all that output. Anyway this can be
157 * boot time and run time configurable.
158 */
159 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
160
161 static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
162
163 /* trace_types holds a link list of available tracers. */
164 static struct tracer *trace_types __read_mostly;
165
166 /* current_trace points to the tracer that is currently active */
167 static struct tracer *current_trace __read_mostly;
168
169 /*
170 * max_tracer_type_len is used to simplify the allocating of
171 * buffers to read userspace tracer names. We keep track of
172 * the longest tracer name registered.
173 */
174 static int max_tracer_type_len;
175
176 /*
177 * trace_types_lock is used to protect the trace_types list.
178 * This lock is also used to keep user access serialized.
179 * Accesses from userspace will grab this lock while userspace
180 * activities happen inside the kernel.
181 */
182 static DEFINE_MUTEX(trace_types_lock);
183
184 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
185 static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
186
187 /* trace_flags holds iter_ctrl options */
188 unsigned long trace_flags = TRACE_ITER_PRINT_PARENT;
189
190 /**
191 * trace_wake_up - wake up tasks waiting for trace input
192 *
193 * Simply wakes up any task that is blocked on the trace_wait
194 * queue. These is used with trace_poll for tasks polling the trace.
195 */
196 void trace_wake_up(void)
197 {
198 /*
199 * The runqueue_is_locked() can fail, but this is the best we
200 * have for now:
201 */
202 if (!(trace_flags & TRACE_ITER_BLOCK) && !runqueue_is_locked())
203 wake_up(&trace_wait);
204 }
205
206 static int __init set_buf_size(char *str)
207 {
208 unsigned long buf_size;
209 int ret;
210
211 if (!str)
212 return 0;
213 ret = strict_strtoul(str, 0, &buf_size);
214 /* nr_entries can not be zero */
215 if (ret < 0 || buf_size == 0)
216 return 0;
217 trace_buf_size = buf_size;
218 return 1;
219 }
220 __setup("trace_buf_size=", set_buf_size);
221
222 unsigned long nsecs_to_usecs(unsigned long nsecs)
223 {
224 return nsecs / 1000;
225 }
226
227 /*
228 * TRACE_ITER_SYM_MASK masks the options in trace_flags that
229 * control the output of kernel symbols.
230 */
231 #define TRACE_ITER_SYM_MASK \
232 (TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR)
233
234 /* These must match the bit postions in trace_iterator_flags */
235 static const char *trace_options[] = {
236 "print-parent",
237 "sym-offset",
238 "sym-addr",
239 "verbose",
240 "raw",
241 "hex",
242 "bin",
243 "block",
244 "stacktrace",
245 "sched-tree",
246 "ftrace_printk",
247 NULL
248 };
249
250 /*
251 * ftrace_max_lock is used to protect the swapping of buffers
252 * when taking a max snapshot. The buffers themselves are
253 * protected by per_cpu spinlocks. But the action of the swap
254 * needs its own lock.
255 *
256 * This is defined as a raw_spinlock_t in order to help
257 * with performance when lockdep debugging is enabled.
258 */
259 static raw_spinlock_t ftrace_max_lock =
260 (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
261
262 /*
263 * Copy the new maximum trace into the separate maximum-trace
264 * structure. (this way the maximum trace is permanently saved,
265 * for later retrieval via /debugfs/tracing/latency_trace)
266 */
267 static void
268 __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
269 {
270 struct trace_array_cpu *data = tr->data[cpu];
271
272 max_tr.cpu = cpu;
273 max_tr.time_start = data->preempt_timestamp;
274
275 data = max_tr.data[cpu];
276 data->saved_latency = tracing_max_latency;
277
278 memcpy(data->comm, tsk->comm, TASK_COMM_LEN);
279 data->pid = tsk->pid;
280 data->uid = tsk->uid;
281 data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
282 data->policy = tsk->policy;
283 data->rt_priority = tsk->rt_priority;
284
285 /* record this tasks comm */
286 tracing_record_cmdline(current);
287 }
288
289 /**
290 * trace_seq_printf - sequence printing of trace information
291 * @s: trace sequence descriptor
292 * @fmt: printf format string
293 *
294 * The tracer may use either sequence operations or its own
295 * copy to user routines. To simplify formating of a trace
296 * trace_seq_printf is used to store strings into a special
297 * buffer (@s). Then the output may be either used by
298 * the sequencer or pulled into another buffer.
299 */
300 int
301 trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
302 {
303 int len = (PAGE_SIZE - 1) - s->len;
304 va_list ap;
305 int ret;
306
307 if (!len)
308 return 0;
309
310 va_start(ap, fmt);
311 ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
312 va_end(ap);
313
314 /* If we can't write it all, don't bother writing anything */
315 if (ret >= len)
316 return 0;
317
318 s->len += ret;
319
320 return len;
321 }
322
323 /**
324 * trace_seq_puts - trace sequence printing of simple string
325 * @s: trace sequence descriptor
326 * @str: simple string to record
327 *
328 * The tracer may use either the sequence operations or its own
329 * copy to user routines. This function records a simple string
330 * into a special buffer (@s) for later retrieval by a sequencer
331 * or other mechanism.
332 */
333 static int
334 trace_seq_puts(struct trace_seq *s, const char *str)
335 {
336 int len = strlen(str);
337
338 if (len > ((PAGE_SIZE - 1) - s->len))
339 return 0;
340
341 memcpy(s->buffer + s->len, str, len);
342 s->len += len;
343
344 return len;
345 }
346
347 static int
348 trace_seq_putc(struct trace_seq *s, unsigned char c)
349 {
350 if (s->len >= (PAGE_SIZE - 1))
351 return 0;
352
353 s->buffer[s->len++] = c;
354
355 return 1;
356 }
357
358 static int
359 trace_seq_putmem(struct trace_seq *s, void *mem, size_t len)
360 {
361 if (len > ((PAGE_SIZE - 1) - s->len))
362 return 0;
363
364 memcpy(s->buffer + s->len, mem, len);
365 s->len += len;
366
367 return len;
368 }
369
370 #define MAX_MEMHEX_BYTES 8
371 #define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1)
372
373 static int
374 trace_seq_putmem_hex(struct trace_seq *s, void *mem, size_t len)
375 {
376 unsigned char hex[HEX_CHARS];
377 unsigned char *data = mem;
378 int i, j;
379
380 #ifdef __BIG_ENDIAN
381 for (i = 0, j = 0; i < len; i++) {
382 #else
383 for (i = len-1, j = 0; i >= 0; i--) {
384 #endif
385 hex[j++] = hex_asc_hi(data[i]);
386 hex[j++] = hex_asc_lo(data[i]);
387 }
388 hex[j++] = ' ';
389
390 return trace_seq_putmem(s, hex, j);
391 }
392
393 static void
394 trace_seq_reset(struct trace_seq *s)
395 {
396 s->len = 0;
397 s->readpos = 0;
398 }
399
400 ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
401 {
402 int len;
403 int ret;
404
405 if (s->len <= s->readpos)
406 return -EBUSY;
407
408 len = s->len - s->readpos;
409 if (cnt > len)
410 cnt = len;
411 ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
412 if (ret)
413 return -EFAULT;
414
415 s->readpos += len;
416 return cnt;
417 }
418
419 static void
420 trace_print_seq(struct seq_file *m, struct trace_seq *s)
421 {
422 int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
423
424 s->buffer[len] = 0;
425 seq_puts(m, s->buffer);
426
427 trace_seq_reset(s);
428 }
429
430 /**
431 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
432 * @tr: tracer
433 * @tsk: the task with the latency
434 * @cpu: The cpu that initiated the trace.
435 *
436 * Flip the buffers between the @tr and the max_tr and record information
437 * about which task was the cause of this latency.
438 */
439 void
440 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
441 {
442 struct ring_buffer *buf = tr->buffer;
443
444 WARN_ON_ONCE(!irqs_disabled());
445 __raw_spin_lock(&ftrace_max_lock);
446
447 tr->buffer = max_tr.buffer;
448 max_tr.buffer = buf;
449
450 ftrace_disable_cpu();
451 ring_buffer_reset(tr->buffer);
452 ftrace_enable_cpu();
453
454 __update_max_tr(tr, tsk, cpu);
455 __raw_spin_unlock(&ftrace_max_lock);
456 }
457
458 /**
459 * update_max_tr_single - only copy one trace over, and reset the rest
460 * @tr - tracer
461 * @tsk - task with the latency
462 * @cpu - the cpu of the buffer to copy.
463 *
464 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
465 */
466 void
467 update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
468 {
469 int ret;
470
471 WARN_ON_ONCE(!irqs_disabled());
472 __raw_spin_lock(&ftrace_max_lock);
473
474 ftrace_disable_cpu();
475
476 ring_buffer_reset(max_tr.buffer);
477 ret = ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu);
478
479 ftrace_enable_cpu();
480
481 WARN_ON_ONCE(ret);
482
483 __update_max_tr(tr, tsk, cpu);
484 __raw_spin_unlock(&ftrace_max_lock);
485 }
486
487 /**
488 * register_tracer - register a tracer with the ftrace system.
489 * @type - the plugin for the tracer
490 *
491 * Register a new plugin tracer.
492 */
493 int register_tracer(struct tracer *type)
494 {
495 struct tracer *t;
496 int len;
497 int ret = 0;
498
499 if (!type->name) {
500 pr_info("Tracer must have a name\n");
501 return -1;
502 }
503
504 mutex_lock(&trace_types_lock);
505 for (t = trace_types; t; t = t->next) {
506 if (strcmp(type->name, t->name) == 0) {
507 /* already found */
508 pr_info("Trace %s already registered\n",
509 type->name);
510 ret = -1;
511 goto out;
512 }
513 }
514
515 #ifdef CONFIG_FTRACE_STARTUP_TEST
516 if (type->selftest) {
517 struct tracer *saved_tracer = current_trace;
518 struct trace_array *tr = &global_trace;
519 int saved_ctrl = tr->ctrl;
520 int i;
521 /*
522 * Run a selftest on this tracer.
523 * Here we reset the trace buffer, and set the current
524 * tracer to be this tracer. The tracer can then run some
525 * internal tracing to verify that everything is in order.
526 * If we fail, we do not register this tracer.
527 */
528 for_each_tracing_cpu(i) {
529 tracing_reset(tr, i);
530 }
531 current_trace = type;
532 tr->ctrl = 0;
533 /* the test is responsible for initializing and enabling */
534 pr_info("Testing tracer %s: ", type->name);
535 ret = type->selftest(type, tr);
536 /* the test is responsible for resetting too */
537 current_trace = saved_tracer;
538 tr->ctrl = saved_ctrl;
539 if (ret) {
540 printk(KERN_CONT "FAILED!\n");
541 goto out;
542 }
543 /* Only reset on passing, to avoid touching corrupted buffers */
544 for_each_tracing_cpu(i) {
545 tracing_reset(tr, i);
546 }
547 printk(KERN_CONT "PASSED\n");
548 }
549 #endif
550
551 type->next = trace_types;
552 trace_types = type;
553 len = strlen(type->name);
554 if (len > max_tracer_type_len)
555 max_tracer_type_len = len;
556
557 out:
558 mutex_unlock(&trace_types_lock);
559
560 return ret;
561 }
562
563 void unregister_tracer(struct tracer *type)
564 {
565 struct tracer **t;
566 int len;
567
568 mutex_lock(&trace_types_lock);
569 for (t = &trace_types; *t; t = &(*t)->next) {
570 if (*t == type)
571 goto found;
572 }
573 pr_info("Trace %s not registered\n", type->name);
574 goto out;
575
576 found:
577 *t = (*t)->next;
578 if (strlen(type->name) != max_tracer_type_len)
579 goto out;
580
581 max_tracer_type_len = 0;
582 for (t = &trace_types; *t; t = &(*t)->next) {
583 len = strlen((*t)->name);
584 if (len > max_tracer_type_len)
585 max_tracer_type_len = len;
586 }
587 out:
588 mutex_unlock(&trace_types_lock);
589 }
590
591 void tracing_reset(struct trace_array *tr, int cpu)
592 {
593 ftrace_disable_cpu();
594 ring_buffer_reset_cpu(tr->buffer, cpu);
595 ftrace_enable_cpu();
596 }
597
598 #define SAVED_CMDLINES 128
599 static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
600 static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
601 static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
602 static int cmdline_idx;
603 static DEFINE_SPINLOCK(trace_cmdline_lock);
604
605 /* temporary disable recording */
606 atomic_t trace_record_cmdline_disabled __read_mostly;
607
608 static void trace_init_cmdlines(void)
609 {
610 memset(&map_pid_to_cmdline, -1, sizeof(map_pid_to_cmdline));
611 memset(&map_cmdline_to_pid, -1, sizeof(map_cmdline_to_pid));
612 cmdline_idx = 0;
613 }
614
615 void trace_stop_cmdline_recording(void);
616
617 static void trace_save_cmdline(struct task_struct *tsk)
618 {
619 unsigned map;
620 unsigned idx;
621
622 if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
623 return;
624
625 /*
626 * It's not the end of the world if we don't get
627 * the lock, but we also don't want to spin
628 * nor do we want to disable interrupts,
629 * so if we miss here, then better luck next time.
630 */
631 if (!spin_trylock(&trace_cmdline_lock))
632 return;
633
634 idx = map_pid_to_cmdline[tsk->pid];
635 if (idx >= SAVED_CMDLINES) {
636 idx = (cmdline_idx + 1) % SAVED_CMDLINES;
637
638 map = map_cmdline_to_pid[idx];
639 if (map <= PID_MAX_DEFAULT)
640 map_pid_to_cmdline[map] = (unsigned)-1;
641
642 map_pid_to_cmdline[tsk->pid] = idx;
643
644 cmdline_idx = idx;
645 }
646
647 memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
648
649 spin_unlock(&trace_cmdline_lock);
650 }
651
652 static char *trace_find_cmdline(int pid)
653 {
654 char *cmdline = "<...>";
655 unsigned map;
656
657 if (!pid)
658 return "<idle>";
659
660 if (pid > PID_MAX_DEFAULT)
661 goto out;
662
663 map = map_pid_to_cmdline[pid];
664 if (map >= SAVED_CMDLINES)
665 goto out;
666
667 cmdline = saved_cmdlines[map];
668
669 out:
670 return cmdline;
671 }
672
673 void tracing_record_cmdline(struct task_struct *tsk)
674 {
675 if (atomic_read(&trace_record_cmdline_disabled))
676 return;
677
678 trace_save_cmdline(tsk);
679 }
680
681 void
682 tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
683 int pc)
684 {
685 struct task_struct *tsk = current;
686
687 entry->preempt_count = pc & 0xff;
688 entry->pid = (tsk) ? tsk->pid : 0;
689 entry->flags =
690 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
691 (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
692 #else
693 TRACE_FLAG_IRQS_NOSUPPORT |
694 #endif
695 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
696 ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
697 (need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
698 }
699
700 void
701 trace_function(struct trace_array *tr, struct trace_array_cpu *data,
702 unsigned long ip, unsigned long parent_ip, unsigned long flags,
703 int pc)
704 {
705 struct ring_buffer_event *event;
706 struct ftrace_entry *entry;
707 unsigned long irq_flags;
708
709 /* If we are reading the ring buffer, don't trace */
710 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
711 return;
712
713 event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
714 &irq_flags);
715 if (!event)
716 return;
717 entry = ring_buffer_event_data(event);
718 tracing_generic_entry_update(&entry->ent, flags, pc);
719 entry->ent.type = TRACE_FN;
720 entry->ip = ip;
721 entry->parent_ip = parent_ip;
722 ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
723 }
724
725 void
726 ftrace(struct trace_array *tr, struct trace_array_cpu *data,
727 unsigned long ip, unsigned long parent_ip, unsigned long flags,
728 int pc)
729 {
730 if (likely(!atomic_read(&data->disabled)))
731 trace_function(tr, data, ip, parent_ip, flags, pc);
732 }
733
734 static void ftrace_trace_stack(struct trace_array *tr,
735 struct trace_array_cpu *data,
736 unsigned long flags,
737 int skip, int pc)
738 {
739 #ifdef CONFIG_STACKTRACE
740 struct ring_buffer_event *event;
741 struct stack_entry *entry;
742 struct stack_trace trace;
743 unsigned long irq_flags;
744
745 if (!(trace_flags & TRACE_ITER_STACKTRACE))
746 return;
747
748 event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
749 &irq_flags);
750 if (!event)
751 return;
752 entry = ring_buffer_event_data(event);
753 tracing_generic_entry_update(&entry->ent, flags, pc);
754 entry->ent.type = TRACE_STACK;
755
756 memset(&entry->caller, 0, sizeof(entry->caller));
757
758 trace.nr_entries = 0;
759 trace.max_entries = FTRACE_STACK_ENTRIES;
760 trace.skip = skip;
761 trace.entries = entry->caller;
762
763 save_stack_trace(&trace);
764 ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
765 #endif
766 }
767
768 void __trace_stack(struct trace_array *tr,
769 struct trace_array_cpu *data,
770 unsigned long flags,
771 int skip)
772 {
773 ftrace_trace_stack(tr, data, flags, skip, preempt_count());
774 }
775
776 static void
777 ftrace_trace_special(void *__tr, void *__data,
778 unsigned long arg1, unsigned long arg2, unsigned long arg3,
779 int pc)
780 {
781 struct ring_buffer_event *event;
782 struct trace_array_cpu *data = __data;
783 struct trace_array *tr = __tr;
784 struct special_entry *entry;
785 unsigned long irq_flags;
786
787 event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
788 &irq_flags);
789 if (!event)
790 return;
791 entry = ring_buffer_event_data(event);
792 tracing_generic_entry_update(&entry->ent, 0, pc);
793 entry->ent.type = TRACE_SPECIAL;
794 entry->arg1 = arg1;
795 entry->arg2 = arg2;
796 entry->arg3 = arg3;
797 ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
798 ftrace_trace_stack(tr, data, irq_flags, 4, pc);
799
800 trace_wake_up();
801 }
802
803 void
804 __trace_special(void *__tr, void *__data,
805 unsigned long arg1, unsigned long arg2, unsigned long arg3)
806 {
807 ftrace_trace_special(__tr, __data, arg1, arg2, arg3, preempt_count());
808 }
809
810 void
811 tracing_sched_switch_trace(struct trace_array *tr,
812 struct trace_array_cpu *data,
813 struct task_struct *prev,
814 struct task_struct *next,
815 unsigned long flags, int pc)
816 {
817 struct ring_buffer_event *event;
818 struct ctx_switch_entry *entry;
819 unsigned long irq_flags;
820
821 event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
822 &irq_flags);
823 if (!event)
824 return;
825 entry = ring_buffer_event_data(event);
826 tracing_generic_entry_update(&entry->ent, flags, pc);
827 entry->ent.type = TRACE_CTX;
828 entry->prev_pid = prev->pid;
829 entry->prev_prio = prev->prio;
830 entry->prev_state = prev->state;
831 entry->next_pid = next->pid;
832 entry->next_prio = next->prio;
833 entry->next_state = next->state;
834 entry->next_cpu = task_cpu(next);
835 ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
836 ftrace_trace_stack(tr, data, flags, 5, pc);
837 }
838
839 void
840 tracing_sched_wakeup_trace(struct trace_array *tr,
841 struct trace_array_cpu *data,
842 struct task_struct *wakee,
843 struct task_struct *curr,
844 unsigned long flags, int pc)
845 {
846 struct ring_buffer_event *event;
847 struct ctx_switch_entry *entry;
848 unsigned long irq_flags;
849
850 event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
851 &irq_flags);
852 if (!event)
853 return;
854 entry = ring_buffer_event_data(event);
855 tracing_generic_entry_update(&entry->ent, flags, pc);
856 entry->ent.type = TRACE_WAKE;
857 entry->prev_pid = curr->pid;
858 entry->prev_prio = curr->prio;
859 entry->prev_state = curr->state;
860 entry->next_pid = wakee->pid;
861 entry->next_prio = wakee->prio;
862 entry->next_state = wakee->state;
863 entry->next_cpu = task_cpu(wakee);
864 ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
865 ftrace_trace_stack(tr, data, flags, 6, pc);
866
867 trace_wake_up();
868 }
869
870 void
871 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3)
872 {
873 struct trace_array *tr = &global_trace;
874 struct trace_array_cpu *data;
875 int cpu;
876 int pc;
877
878 if (tracing_disabled || !tr->ctrl)
879 return;
880
881 pc = preempt_count();
882 preempt_disable_notrace();
883 cpu = raw_smp_processor_id();
884 data = tr->data[cpu];
885
886 if (likely(!atomic_read(&data->disabled)))
887 ftrace_trace_special(tr, data, arg1, arg2, arg3, pc);
888
889 preempt_enable_notrace();
890 }
891
892 #ifdef CONFIG_FUNCTION_TRACER
893 static void
894 function_trace_call(unsigned long ip, unsigned long parent_ip)
895 {
896 struct trace_array *tr = &global_trace;
897 struct trace_array_cpu *data;
898 unsigned long flags;
899 long disabled;
900 int cpu, resched;
901 int pc;
902
903 if (unlikely(!ftrace_function_enabled))
904 return;
905
906 pc = preempt_count();
907 resched = ftrace_preempt_disable();
908 local_save_flags(flags);
909 cpu = raw_smp_processor_id();
910 data = tr->data[cpu];
911 disabled = atomic_inc_return(&data->disabled);
912
913 if (likely(disabled == 1))
914 trace_function(tr, data, ip, parent_ip, flags, pc);
915
916 atomic_dec(&data->disabled);
917 ftrace_preempt_enable(resched);
918 }
919
920 static struct ftrace_ops trace_ops __read_mostly =
921 {
922 .func = function_trace_call,
923 };
924
925 void tracing_start_function_trace(void)
926 {
927 ftrace_function_enabled = 0;
928 register_ftrace_function(&trace_ops);
929 if (tracer_enabled)
930 ftrace_function_enabled = 1;
931 }
932
933 void tracing_stop_function_trace(void)
934 {
935 ftrace_function_enabled = 0;
936 unregister_ftrace_function(&trace_ops);
937 }
938 #endif
939
940 enum trace_file_type {
941 TRACE_FILE_LAT_FMT = 1,
942 };
943
944 static void trace_iterator_increment(struct trace_iterator *iter, int cpu)
945 {
946 /* Don't allow ftrace to trace into the ring buffers */
947 ftrace_disable_cpu();
948
949 iter->idx++;
950 if (iter->buffer_iter[iter->cpu])
951 ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
952
953 ftrace_enable_cpu();
954 }
955
956 static struct trace_entry *
957 peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts)
958 {
959 struct ring_buffer_event *event;
960 struct ring_buffer_iter *buf_iter = iter->buffer_iter[cpu];
961
962 /* Don't allow ftrace to trace into the ring buffers */
963 ftrace_disable_cpu();
964
965 if (buf_iter)
966 event = ring_buffer_iter_peek(buf_iter, ts);
967 else
968 event = ring_buffer_peek(iter->tr->buffer, cpu, ts);
969
970 ftrace_enable_cpu();
971
972 return event ? ring_buffer_event_data(event) : NULL;
973 }
974
975 static struct trace_entry *
976 __find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts)
977 {
978 struct ring_buffer *buffer = iter->tr->buffer;
979 struct trace_entry *ent, *next = NULL;
980 u64 next_ts = 0, ts;
981 int next_cpu = -1;
982 int cpu;
983
984 for_each_tracing_cpu(cpu) {
985
986 if (ring_buffer_empty_cpu(buffer, cpu))
987 continue;
988
989 ent = peek_next_entry(iter, cpu, &ts);
990
991 /*
992 * Pick the entry with the smallest timestamp:
993 */
994 if (ent && (!next || ts < next_ts)) {
995 next = ent;
996 next_cpu = cpu;
997 next_ts = ts;
998 }
999 }
1000
1001 if (ent_cpu)
1002 *ent_cpu = next_cpu;
1003
1004 if (ent_ts)
1005 *ent_ts = next_ts;
1006
1007 return next;
1008 }
1009
1010 /* Find the next real entry, without updating the iterator itself */
1011 static struct trace_entry *
1012 find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts)
1013 {
1014 return __find_next_entry(iter, ent_cpu, ent_ts);
1015 }
1016
1017 /* Find the next real entry, and increment the iterator to the next entry */
1018 static void *find_next_entry_inc(struct trace_iterator *iter)
1019 {
1020 iter->ent = __find_next_entry(iter, &iter->cpu, &iter->ts);
1021
1022 if (iter->ent)
1023 trace_iterator_increment(iter, iter->cpu);
1024
1025 return iter->ent ? iter : NULL;
1026 }
1027
1028 static void trace_consume(struct trace_iterator *iter)
1029 {
1030 /* Don't allow ftrace to trace into the ring buffers */
1031 ftrace_disable_cpu();
1032 ring_buffer_consume(iter->tr->buffer, iter->cpu, &iter->ts);
1033 ftrace_enable_cpu();
1034 }
1035
1036 static void *s_next(struct seq_file *m, void *v, loff_t *pos)
1037 {
1038 struct trace_iterator *iter = m->private;
1039 int i = (int)*pos;
1040 void *ent;
1041
1042 (*pos)++;
1043
1044 /* can't go backwards */
1045 if (iter->idx > i)
1046 return NULL;
1047
1048 if (iter->idx < 0)
1049 ent = find_next_entry_inc(iter);
1050 else
1051 ent = iter;
1052
1053 while (ent && iter->idx < i)
1054 ent = find_next_entry_inc(iter);
1055
1056 iter->pos = *pos;
1057
1058 return ent;
1059 }
1060
1061 static void *s_start(struct seq_file *m, loff_t *pos)
1062 {
1063 struct trace_iterator *iter = m->private;
1064 void *p = NULL;
1065 loff_t l = 0;
1066 int cpu;
1067
1068 mutex_lock(&trace_types_lock);
1069
1070 if (!current_trace || current_trace != iter->trace) {
1071 mutex_unlock(&trace_types_lock);
1072 return NULL;
1073 }
1074
1075 atomic_inc(&trace_record_cmdline_disabled);
1076
1077 /* let the tracer grab locks here if needed */
1078 if (current_trace->start)
1079 current_trace->start(iter);
1080
1081 if (*pos != iter->pos) {
1082 iter->ent = NULL;
1083 iter->cpu = 0;
1084 iter->idx = -1;
1085
1086 ftrace_disable_cpu();
1087
1088 for_each_tracing_cpu(cpu) {
1089 ring_buffer_iter_reset(iter->buffer_iter[cpu]);
1090 }
1091
1092 ftrace_enable_cpu();
1093
1094 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
1095 ;
1096
1097 } else {
1098 l = *pos - 1;
1099 p = s_next(m, p, &l);
1100 }
1101
1102 return p;
1103 }
1104
1105 static void s_stop(struct seq_file *m, void *p)
1106 {
1107 struct trace_iterator *iter = m->private;
1108
1109 atomic_dec(&trace_record_cmdline_disabled);
1110
1111 /* let the tracer release locks here if needed */
1112 if (current_trace && current_trace == iter->trace && iter->trace->stop)
1113 iter->trace->stop(iter);
1114
1115 mutex_unlock(&trace_types_lock);
1116 }
1117
1118 #define KRETPROBE_MSG "[unknown/kretprobe'd]"
1119
1120 #ifdef CONFIG_KRETPROBES
1121 static inline int kretprobed(unsigned long addr)
1122 {
1123 return addr == (unsigned long)kretprobe_trampoline;
1124 }
1125 #else
1126 static inline int kretprobed(unsigned long addr)
1127 {
1128 return 0;
1129 }
1130 #endif /* CONFIG_KRETPROBES */
1131
1132 static int
1133 seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
1134 {
1135 #ifdef CONFIG_KALLSYMS
1136 char str[KSYM_SYMBOL_LEN];
1137
1138 kallsyms_lookup(address, NULL, NULL, NULL, str);
1139
1140 return trace_seq_printf(s, fmt, str);
1141 #endif
1142 return 1;
1143 }
1144
1145 static int
1146 seq_print_sym_offset(struct trace_seq *s, const char *fmt,
1147 unsigned long address)
1148 {
1149 #ifdef CONFIG_KALLSYMS
1150 char str[KSYM_SYMBOL_LEN];
1151
1152 sprint_symbol(str, address);
1153 return trace_seq_printf(s, fmt, str);
1154 #endif
1155 return 1;
1156 }
1157
1158 #ifndef CONFIG_64BIT
1159 # define IP_FMT "%08lx"
1160 #else
1161 # define IP_FMT "%016lx"
1162 #endif
1163
1164 static int
1165 seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
1166 {
1167 int ret;
1168
1169 if (!ip)
1170 return trace_seq_printf(s, "0");
1171
1172 if (sym_flags & TRACE_ITER_SYM_OFFSET)
1173 ret = seq_print_sym_offset(s, "%s", ip);
1174 else
1175 ret = seq_print_sym_short(s, "%s", ip);
1176
1177 if (!ret)
1178 return 0;
1179
1180 if (sym_flags & TRACE_ITER_SYM_ADDR)
1181 ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
1182 return ret;
1183 }
1184
1185 static void print_lat_help_header(struct seq_file *m)
1186 {
1187 seq_puts(m, "# _------=> CPU# \n");
1188 seq_puts(m, "# / _-----=> irqs-off \n");
1189 seq_puts(m, "# | / _----=> need-resched \n");
1190 seq_puts(m, "# || / _---=> hardirq/softirq \n");
1191 seq_puts(m, "# ||| / _--=> preempt-depth \n");
1192 seq_puts(m, "# |||| / \n");
1193 seq_puts(m, "# ||||| delay \n");
1194 seq_puts(m, "# cmd pid ||||| time | caller \n");
1195 seq_puts(m, "# \\ / ||||| \\ | / \n");
1196 }
1197
1198 static void print_func_help_header(struct seq_file *m)
1199 {
1200 seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1201 seq_puts(m, "# | | | | |\n");
1202 }
1203
1204
1205 static void
1206 print_trace_header(struct seq_file *m, struct trace_iterator *iter)
1207 {
1208 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1209 struct trace_array *tr = iter->tr;
1210 struct trace_array_cpu *data = tr->data[tr->cpu];
1211 struct tracer *type = current_trace;
1212 unsigned long total;
1213 unsigned long entries;
1214 const char *name = "preemption";
1215
1216 if (type)
1217 name = type->name;
1218
1219 entries = ring_buffer_entries(iter->tr->buffer);
1220 total = entries +
1221 ring_buffer_overruns(iter->tr->buffer);
1222
1223 seq_printf(m, "%s latency trace v1.1.5 on %s\n",
1224 name, UTS_RELEASE);
1225 seq_puts(m, "-----------------------------------"
1226 "---------------------------------\n");
1227 seq_printf(m, " latency: %lu us, #%lu/%lu, CPU#%d |"
1228 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1229 nsecs_to_usecs(data->saved_latency),
1230 entries,
1231 total,
1232 tr->cpu,
1233 #if defined(CONFIG_PREEMPT_NONE)
1234 "server",
1235 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1236 "desktop",
1237 #elif defined(CONFIG_PREEMPT)
1238 "preempt",
1239 #else
1240 "unknown",
1241 #endif
1242 /* These are reserved for later use */
1243 0, 0, 0, 0);
1244 #ifdef CONFIG_SMP
1245 seq_printf(m, " #P:%d)\n", num_online_cpus());
1246 #else
1247 seq_puts(m, ")\n");
1248 #endif
1249 seq_puts(m, " -----------------\n");
1250 seq_printf(m, " | task: %.16s-%d "
1251 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1252 data->comm, data->pid, data->uid, data->nice,
1253 data->policy, data->rt_priority);
1254 seq_puts(m, " -----------------\n");
1255
1256 if (data->critical_start) {
1257 seq_puts(m, " => started at: ");
1258 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
1259 trace_print_seq(m, &iter->seq);
1260 seq_puts(m, "\n => ended at: ");
1261 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
1262 trace_print_seq(m, &iter->seq);
1263 seq_puts(m, "\n");
1264 }
1265
1266 seq_puts(m, "\n");
1267 }
1268
1269 static void
1270 lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
1271 {
1272 int hardirq, softirq;
1273 char *comm;
1274
1275 comm = trace_find_cmdline(entry->pid);
1276
1277 trace_seq_printf(s, "%8.8s-%-5d ", comm, entry->pid);
1278 trace_seq_printf(s, "%3d", cpu);
1279 trace_seq_printf(s, "%c%c",
1280 (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
1281 (entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' : '.',
1282 ((entry->flags & TRACE_FLAG_NEED_RESCHED) ? 'N' : '.'));
1283
1284 hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
1285 softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
1286 if (hardirq && softirq) {
1287 trace_seq_putc(s, 'H');
1288 } else {
1289 if (hardirq) {
1290 trace_seq_putc(s, 'h');
1291 } else {
1292 if (softirq)
1293 trace_seq_putc(s, 's');
1294 else
1295 trace_seq_putc(s, '.');
1296 }
1297 }
1298
1299 if (entry->preempt_count)
1300 trace_seq_printf(s, "%x", entry->preempt_count);
1301 else
1302 trace_seq_puts(s, ".");
1303 }
1304
1305 unsigned long preempt_mark_thresh = 100;
1306
1307 static void
1308 lat_print_timestamp(struct trace_seq *s, u64 abs_usecs,
1309 unsigned long rel_usecs)
1310 {
1311 trace_seq_printf(s, " %4lldus", abs_usecs);
1312 if (rel_usecs > preempt_mark_thresh)
1313 trace_seq_puts(s, "!: ");
1314 else if (rel_usecs > 1)
1315 trace_seq_puts(s, "+: ");
1316 else
1317 trace_seq_puts(s, " : ");
1318 }
1319
1320 static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
1321
1322 /*
1323 * The message is supposed to contain an ending newline.
1324 * If the printing stops prematurely, try to add a newline of our own.
1325 */
1326 void trace_seq_print_cont(struct trace_seq *s, struct trace_iterator *iter)
1327 {
1328 struct trace_entry *ent;
1329 struct trace_field_cont *cont;
1330 bool ok = true;
1331
1332 ent = peek_next_entry(iter, iter->cpu, NULL);
1333 if (!ent || ent->type != TRACE_CONT) {
1334 trace_seq_putc(s, '\n');
1335 return;
1336 }
1337
1338 do {
1339 cont = (struct trace_field_cont *)ent;
1340 if (ok)
1341 ok = (trace_seq_printf(s, "%s", cont->buf) > 0);
1342
1343 ftrace_disable_cpu();
1344
1345 if (iter->buffer_iter[iter->cpu])
1346 ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
1347 else
1348 ring_buffer_consume(iter->tr->buffer, iter->cpu, NULL);
1349
1350 ftrace_enable_cpu();
1351
1352 ent = peek_next_entry(iter, iter->cpu, NULL);
1353 } while (ent && ent->type == TRACE_CONT);
1354
1355 if (!ok)
1356 trace_seq_putc(s, '\n');
1357 }
1358
1359 static enum print_line_t
1360 print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
1361 {
1362 struct trace_seq *s = &iter->seq;
1363 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1364 struct trace_entry *next_entry;
1365 unsigned long verbose = (trace_flags & TRACE_ITER_VERBOSE);
1366 struct trace_entry *entry = iter->ent;
1367 unsigned long abs_usecs;
1368 unsigned long rel_usecs;
1369 u64 next_ts;
1370 char *comm;
1371 int S, T;
1372 int i;
1373 unsigned state;
1374
1375 if (entry->type == TRACE_CONT)
1376 return TRACE_TYPE_HANDLED;
1377
1378 next_entry = find_next_entry(iter, NULL, &next_ts);
1379 if (!next_entry)
1380 next_ts = iter->ts;
1381 rel_usecs = ns2usecs(next_ts - iter->ts);
1382 abs_usecs = ns2usecs(iter->ts - iter->tr->time_start);
1383
1384 if (verbose) {
1385 comm = trace_find_cmdline(entry->pid);
1386 trace_seq_printf(s, "%16s %5d %3d %d %08x %08x [%08lx]"
1387 " %ld.%03ldms (+%ld.%03ldms): ",
1388 comm,
1389 entry->pid, cpu, entry->flags,
1390 entry->preempt_count, trace_idx,
1391 ns2usecs(iter->ts),
1392 abs_usecs/1000,
1393 abs_usecs % 1000, rel_usecs/1000,
1394 rel_usecs % 1000);
1395 } else {
1396 lat_print_generic(s, entry, cpu);
1397 lat_print_timestamp(s, abs_usecs, rel_usecs);
1398 }
1399 switch (entry->type) {
1400 case TRACE_FN: {
1401 struct ftrace_entry *field;
1402
1403 trace_assign_type(field, entry);
1404
1405 seq_print_ip_sym(s, field->ip, sym_flags);
1406 trace_seq_puts(s, " (");
1407 if (kretprobed(field->parent_ip))
1408 trace_seq_puts(s, KRETPROBE_MSG);
1409 else
1410 seq_print_ip_sym(s, field->parent_ip, sym_flags);
1411 trace_seq_puts(s, ")\n");
1412 break;
1413 }
1414 case TRACE_CTX:
1415 case TRACE_WAKE: {
1416 struct ctx_switch_entry *field;
1417
1418 trace_assign_type(field, entry);
1419
1420 T = field->next_state < sizeof(state_to_char) ?
1421 state_to_char[field->next_state] : 'X';
1422
1423 state = field->prev_state ?
1424 __ffs(field->prev_state) + 1 : 0;
1425 S = state < sizeof(state_to_char) - 1 ? state_to_char[state] : 'X';
1426 comm = trace_find_cmdline(field->next_pid);
1427 trace_seq_printf(s, " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
1428 field->prev_pid,
1429 field->prev_prio,
1430 S, entry->type == TRACE_CTX ? "==>" : " +",
1431 field->next_cpu,
1432 field->next_pid,
1433 field->next_prio,
1434 T, comm);
1435 break;
1436 }
1437 case TRACE_SPECIAL: {
1438 struct special_entry *field;
1439
1440 trace_assign_type(field, entry);
1441
1442 trace_seq_printf(s, "# %ld %ld %ld\n",
1443 field->arg1,
1444 field->arg2,
1445 field->arg3);
1446 break;
1447 }
1448 case TRACE_STACK: {
1449 struct stack_entry *field;
1450
1451 trace_assign_type(field, entry);
1452
1453 for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
1454 if (i)
1455 trace_seq_puts(s, " <= ");
1456 seq_print_ip_sym(s, field->caller[i], sym_flags);
1457 }
1458 trace_seq_puts(s, "\n");
1459 break;
1460 }
1461 case TRACE_PRINT: {
1462 struct print_entry *field;
1463
1464 trace_assign_type(field, entry);
1465
1466 seq_print_ip_sym(s, field->ip, sym_flags);
1467 trace_seq_printf(s, ": %s", field->buf);
1468 if (entry->flags & TRACE_FLAG_CONT)
1469 trace_seq_print_cont(s, iter);
1470 break;
1471 }
1472 default:
1473 trace_seq_printf(s, "Unknown type %d\n", entry->type);
1474 }
1475 return TRACE_TYPE_HANDLED;
1476 }
1477
1478 static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
1479 {
1480 struct trace_seq *s = &iter->seq;
1481 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1482 struct trace_entry *entry;
1483 unsigned long usec_rem;
1484 unsigned long long t;
1485 unsigned long secs;
1486 char *comm;
1487 int ret;
1488 int S, T;
1489 int i;
1490
1491 entry = iter->ent;
1492
1493 if (entry->type == TRACE_CONT)
1494 return TRACE_TYPE_HANDLED;
1495
1496 comm = trace_find_cmdline(iter->ent->pid);
1497
1498 t = ns2usecs(iter->ts);
1499 usec_rem = do_div(t, 1000000ULL);
1500 secs = (unsigned long)t;
1501
1502 ret = trace_seq_printf(s, "%16s-%-5d ", comm, entry->pid);
1503 if (!ret)
1504 return TRACE_TYPE_PARTIAL_LINE;
1505 ret = trace_seq_printf(s, "[%03d] ", iter->cpu);
1506 if (!ret)
1507 return TRACE_TYPE_PARTIAL_LINE;
1508 ret = trace_seq_printf(s, "%5lu.%06lu: ", secs, usec_rem);
1509 if (!ret)
1510 return TRACE_TYPE_PARTIAL_LINE;
1511
1512 switch (entry->type) {
1513 case TRACE_FN: {
1514 struct ftrace_entry *field;
1515
1516 trace_assign_type(field, entry);
1517
1518 ret = seq_print_ip_sym(s, field->ip, sym_flags);
1519 if (!ret)
1520 return TRACE_TYPE_PARTIAL_LINE;
1521 if ((sym_flags & TRACE_ITER_PRINT_PARENT) &&
1522 field->parent_ip) {
1523 ret = trace_seq_printf(s, " <-");
1524 if (!ret)
1525 return TRACE_TYPE_PARTIAL_LINE;
1526 if (kretprobed(field->parent_ip))
1527 ret = trace_seq_puts(s, KRETPROBE_MSG);
1528 else
1529 ret = seq_print_ip_sym(s,
1530 field->parent_ip,
1531 sym_flags);
1532 if (!ret)
1533 return TRACE_TYPE_PARTIAL_LINE;
1534 }
1535 ret = trace_seq_printf(s, "\n");
1536 if (!ret)
1537 return TRACE_TYPE_PARTIAL_LINE;
1538 break;
1539 }
1540 case TRACE_CTX:
1541 case TRACE_WAKE: {
1542 struct ctx_switch_entry *field;
1543
1544 trace_assign_type(field, entry);
1545
1546 S = field->prev_state < sizeof(state_to_char) ?
1547 state_to_char[field->prev_state] : 'X';
1548 T = field->next_state < sizeof(state_to_char) ?
1549 state_to_char[field->next_state] : 'X';
1550 ret = trace_seq_printf(s, " %5d:%3d:%c %s [%03d] %5d:%3d:%c\n",
1551 field->prev_pid,
1552 field->prev_prio,
1553 S,
1554 entry->type == TRACE_CTX ? "==>" : " +",
1555 field->next_cpu,
1556 field->next_pid,
1557 field->next_prio,
1558 T);
1559 if (!ret)
1560 return TRACE_TYPE_PARTIAL_LINE;
1561 break;
1562 }
1563 case TRACE_SPECIAL: {
1564 struct special_entry *field;
1565
1566 trace_assign_type(field, entry);
1567
1568 ret = trace_seq_printf(s, "# %ld %ld %ld\n",
1569 field->arg1,
1570 field->arg2,
1571 field->arg3);
1572 if (!ret)
1573 return TRACE_TYPE_PARTIAL_LINE;
1574 break;
1575 }
1576 case TRACE_STACK: {
1577 struct stack_entry *field;
1578
1579 trace_assign_type(field, entry);
1580
1581 for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
1582 if (i) {
1583 ret = trace_seq_puts(s, " <= ");
1584 if (!ret)
1585 return TRACE_TYPE_PARTIAL_LINE;
1586 }
1587 ret = seq_print_ip_sym(s, field->caller[i],
1588 sym_flags);
1589 if (!ret)
1590 return TRACE_TYPE_PARTIAL_LINE;
1591 }
1592 ret = trace_seq_puts(s, "\n");
1593 if (!ret)
1594 return TRACE_TYPE_PARTIAL_LINE;
1595 break;
1596 }
1597 case TRACE_PRINT: {
1598 struct print_entry *field;
1599
1600 trace_assign_type(field, entry);
1601
1602 seq_print_ip_sym(s, field->ip, sym_flags);
1603 trace_seq_printf(s, ": %s", field->buf);
1604 if (entry->flags & TRACE_FLAG_CONT)
1605 trace_seq_print_cont(s, iter);
1606 break;
1607 }
1608 }
1609 return TRACE_TYPE_HANDLED;
1610 }
1611
1612 static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
1613 {
1614 struct trace_seq *s = &iter->seq;
1615 struct trace_entry *entry;
1616 int ret;
1617 int S, T;
1618
1619 entry = iter->ent;
1620
1621 if (entry->type == TRACE_CONT)
1622 return TRACE_TYPE_HANDLED;
1623
1624 ret = trace_seq_printf(s, "%d %d %llu ",
1625 entry->pid, iter->cpu, iter->ts);
1626 if (!ret)
1627 return TRACE_TYPE_PARTIAL_LINE;
1628
1629 switch (entry->type) {
1630 case TRACE_FN: {
1631 struct ftrace_entry *field;
1632
1633 trace_assign_type(field, entry);
1634
1635 ret = trace_seq_printf(s, "%x %x\n",
1636 field->ip,
1637 field->parent_ip);
1638 if (!ret)
1639 return TRACE_TYPE_PARTIAL_LINE;
1640 break;
1641 }
1642 case TRACE_CTX:
1643 case TRACE_WAKE: {
1644 struct ctx_switch_entry *field;
1645
1646 trace_assign_type(field, entry);
1647
1648 S = field->prev_state < sizeof(state_to_char) ?
1649 state_to_char[field->prev_state] : 'X';
1650 T = field->next_state < sizeof(state_to_char) ?
1651 state_to_char[field->next_state] : 'X';
1652 if (entry->type == TRACE_WAKE)
1653 S = '+';
1654 ret = trace_seq_printf(s, "%d %d %c %d %d %d %c\n",
1655 field->prev_pid,
1656 field->prev_prio,
1657 S,
1658 field->next_cpu,
1659 field->next_pid,
1660 field->next_prio,
1661 T);
1662 if (!ret)
1663 return TRACE_TYPE_PARTIAL_LINE;
1664 break;
1665 }
1666 case TRACE_SPECIAL:
1667 case TRACE_STACK: {
1668 struct special_entry *field;
1669
1670 trace_assign_type(field, entry);
1671
1672 ret = trace_seq_printf(s, "# %ld %ld %ld\n",
1673 field->arg1,
1674 field->arg2,
1675 field->arg3);
1676 if (!ret)
1677 return TRACE_TYPE_PARTIAL_LINE;
1678 break;
1679 }
1680 case TRACE_PRINT: {
1681 struct print_entry *field;
1682
1683 trace_assign_type(field, entry);
1684
1685 trace_seq_printf(s, "# %lx %s", field->ip, field->buf);
1686 if (entry->flags & TRACE_FLAG_CONT)
1687 trace_seq_print_cont(s, iter);
1688 break;
1689 }
1690 }
1691 return TRACE_TYPE_HANDLED;
1692 }
1693
1694 #define SEQ_PUT_FIELD_RET(s, x) \
1695 do { \
1696 if (!trace_seq_putmem(s, &(x), sizeof(x))) \
1697 return 0; \
1698 } while (0)
1699
1700 #define SEQ_PUT_HEX_FIELD_RET(s, x) \
1701 do { \
1702 BUILD_BUG_ON(sizeof(x) > MAX_MEMHEX_BYTES); \
1703 if (!trace_seq_putmem_hex(s, &(x), sizeof(x))) \
1704 return 0; \
1705 } while (0)
1706
1707 static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
1708 {
1709 struct trace_seq *s = &iter->seq;
1710 unsigned char newline = '\n';
1711 struct trace_entry *entry;
1712 int S, T;
1713
1714 entry = iter->ent;
1715
1716 if (entry->type == TRACE_CONT)
1717 return TRACE_TYPE_HANDLED;
1718
1719 SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
1720 SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
1721 SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
1722
1723 switch (entry->type) {
1724 case TRACE_FN: {
1725 struct ftrace_entry *field;
1726
1727 trace_assign_type(field, entry);
1728
1729 SEQ_PUT_HEX_FIELD_RET(s, field->ip);
1730 SEQ_PUT_HEX_FIELD_RET(s, field->parent_ip);
1731 break;
1732 }
1733 case TRACE_CTX:
1734 case TRACE_WAKE: {
1735 struct ctx_switch_entry *field;
1736
1737 trace_assign_type(field, entry);
1738
1739 S = field->prev_state < sizeof(state_to_char) ?
1740 state_to_char[field->prev_state] : 'X';
1741 T = field->next_state < sizeof(state_to_char) ?
1742 state_to_char[field->next_state] : 'X';
1743 if (entry->type == TRACE_WAKE)
1744 S = '+';
1745 SEQ_PUT_HEX_FIELD_RET(s, field->prev_pid);
1746 SEQ_PUT_HEX_FIELD_RET(s, field->prev_prio);
1747 SEQ_PUT_HEX_FIELD_RET(s, S);
1748 SEQ_PUT_HEX_FIELD_RET(s, field->next_cpu);
1749 SEQ_PUT_HEX_FIELD_RET(s, field->next_pid);
1750 SEQ_PUT_HEX_FIELD_RET(s, field->next_prio);
1751 SEQ_PUT_HEX_FIELD_RET(s, T);
1752 break;
1753 }
1754 case TRACE_SPECIAL:
1755 case TRACE_STACK: {
1756 struct special_entry *field;
1757
1758 trace_assign_type(field, entry);
1759
1760 SEQ_PUT_HEX_FIELD_RET(s, field->arg1);
1761 SEQ_PUT_HEX_FIELD_RET(s, field->arg2);
1762 SEQ_PUT_HEX_FIELD_RET(s, field->arg3);
1763 break;
1764 }
1765 }
1766 SEQ_PUT_FIELD_RET(s, newline);
1767
1768 return TRACE_TYPE_HANDLED;
1769 }
1770
1771 static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
1772 {
1773 struct trace_seq *s = &iter->seq;
1774 struct trace_entry *entry;
1775
1776 entry = iter->ent;
1777
1778 if (entry->type == TRACE_CONT)
1779 return TRACE_TYPE_HANDLED;
1780
1781 SEQ_PUT_FIELD_RET(s, entry->pid);
1782 SEQ_PUT_FIELD_RET(s, iter->cpu);
1783 SEQ_PUT_FIELD_RET(s, iter->ts);
1784
1785 switch (entry->type) {
1786 case TRACE_FN: {
1787 struct ftrace_entry *field;
1788
1789 trace_assign_type(field, entry);
1790
1791 SEQ_PUT_FIELD_RET(s, field->ip);
1792 SEQ_PUT_FIELD_RET(s, field->parent_ip);
1793 break;
1794 }
1795 case TRACE_CTX: {
1796 struct ctx_switch_entry *field;
1797
1798 trace_assign_type(field, entry);
1799
1800 SEQ_PUT_FIELD_RET(s, field->prev_pid);
1801 SEQ_PUT_FIELD_RET(s, field->prev_prio);
1802 SEQ_PUT_FIELD_RET(s, field->prev_state);
1803 SEQ_PUT_FIELD_RET(s, field->next_pid);
1804 SEQ_PUT_FIELD_RET(s, field->next_prio);
1805 SEQ_PUT_FIELD_RET(s, field->next_state);
1806 break;
1807 }
1808 case TRACE_SPECIAL:
1809 case TRACE_STACK: {
1810 struct special_entry *field;
1811
1812 trace_assign_type(field, entry);
1813
1814 SEQ_PUT_FIELD_RET(s, field->arg1);
1815 SEQ_PUT_FIELD_RET(s, field->arg2);
1816 SEQ_PUT_FIELD_RET(s, field->arg3);
1817 break;
1818 }
1819 }
1820 return 1;
1821 }
1822
1823 static int trace_empty(struct trace_iterator *iter)
1824 {
1825 int cpu;
1826
1827 for_each_tracing_cpu(cpu) {
1828 if (iter->buffer_iter[cpu]) {
1829 if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
1830 return 0;
1831 } else {
1832 if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
1833 return 0;
1834 }
1835 }
1836
1837 return 1;
1838 }
1839
1840 static enum print_line_t print_trace_line(struct trace_iterator *iter)
1841 {
1842 enum print_line_t ret;
1843
1844 if (iter->trace && iter->trace->print_line) {
1845 ret = iter->trace->print_line(iter);
1846 if (ret != TRACE_TYPE_UNHANDLED)
1847 return ret;
1848 }
1849
1850 if (trace_flags & TRACE_ITER_BIN)
1851 return print_bin_fmt(iter);
1852
1853 if (trace_flags & TRACE_ITER_HEX)
1854 return print_hex_fmt(iter);
1855
1856 if (trace_flags & TRACE_ITER_RAW)
1857 return print_raw_fmt(iter);
1858
1859 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
1860 return print_lat_fmt(iter, iter->idx, iter->cpu);
1861
1862 return print_trace_fmt(iter);
1863 }
1864
1865 static int s_show(struct seq_file *m, void *v)
1866 {
1867 struct trace_iterator *iter = v;
1868
1869 if (iter->ent == NULL) {
1870 if (iter->tr) {
1871 seq_printf(m, "# tracer: %s\n", iter->trace->name);
1872 seq_puts(m, "#\n");
1873 }
1874 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
1875 /* print nothing if the buffers are empty */
1876 if (trace_empty(iter))
1877 return 0;
1878 print_trace_header(m, iter);
1879 if (!(trace_flags & TRACE_ITER_VERBOSE))
1880 print_lat_help_header(m);
1881 } else {
1882 if (!(trace_flags & TRACE_ITER_VERBOSE))
1883 print_func_help_header(m);
1884 }
1885 } else {
1886 print_trace_line(iter);
1887 trace_print_seq(m, &iter->seq);
1888 }
1889
1890 return 0;
1891 }
1892
1893 static struct seq_operations tracer_seq_ops = {
1894 .start = s_start,
1895 .next = s_next,
1896 .stop = s_stop,
1897 .show = s_show,
1898 };
1899
1900 static struct trace_iterator *
1901 __tracing_open(struct inode *inode, struct file *file, int *ret)
1902 {
1903 struct trace_iterator *iter;
1904 struct seq_file *m;
1905 int cpu;
1906
1907 if (tracing_disabled) {
1908 *ret = -ENODEV;
1909 return NULL;
1910 }
1911
1912 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1913 if (!iter) {
1914 *ret = -ENOMEM;
1915 goto out;
1916 }
1917
1918 mutex_lock(&trace_types_lock);
1919 if (current_trace && current_trace->print_max)
1920 iter->tr = &max_tr;
1921 else
1922 iter->tr = inode->i_private;
1923 iter->trace = current_trace;
1924 iter->pos = -1;
1925
1926 for_each_tracing_cpu(cpu) {
1927
1928 iter->buffer_iter[cpu] =
1929 ring_buffer_read_start(iter->tr->buffer, cpu);
1930
1931 if (!iter->buffer_iter[cpu])
1932 goto fail_buffer;
1933 }
1934
1935 /* TODO stop tracer */
1936 *ret = seq_open(file, &tracer_seq_ops);
1937 if (*ret)
1938 goto fail_buffer;
1939
1940 m = file->private_data;
1941 m->private = iter;
1942
1943 /* stop the trace while dumping */
1944 if (iter->tr->ctrl) {
1945 tracer_enabled = 0;
1946 ftrace_function_enabled = 0;
1947 }
1948
1949 if (iter->trace && iter->trace->open)
1950 iter->trace->open(iter);
1951
1952 mutex_unlock(&trace_types_lock);
1953
1954 out:
1955 return iter;
1956
1957 fail_buffer:
1958 for_each_tracing_cpu(cpu) {
1959 if (iter->buffer_iter[cpu])
1960 ring_buffer_read_finish(iter->buffer_iter[cpu]);
1961 }
1962 mutex_unlock(&trace_types_lock);
1963
1964 return ERR_PTR(-ENOMEM);
1965 }
1966
1967 int tracing_open_generic(struct inode *inode, struct file *filp)
1968 {
1969 if (tracing_disabled)
1970 return -ENODEV;
1971
1972 filp->private_data = inode->i_private;
1973 return 0;
1974 }
1975
1976 int tracing_release(struct inode *inode, struct file *file)
1977 {
1978 struct seq_file *m = (struct seq_file *)file->private_data;
1979 struct trace_iterator *iter = m->private;
1980 int cpu;
1981
1982 mutex_lock(&trace_types_lock);
1983 for_each_tracing_cpu(cpu) {
1984 if (iter->buffer_iter[cpu])
1985 ring_buffer_read_finish(iter->buffer_iter[cpu]);
1986 }
1987
1988 if (iter->trace && iter->trace->close)
1989 iter->trace->close(iter);
1990
1991 /* reenable tracing if it was previously enabled */
1992 if (iter->tr->ctrl) {
1993 tracer_enabled = 1;
1994 /*
1995 * It is safe to enable function tracing even if it
1996 * isn't used
1997 */
1998 ftrace_function_enabled = 1;
1999 }
2000 mutex_unlock(&trace_types_lock);
2001
2002 seq_release(inode, file);
2003 kfree(iter);
2004 return 0;
2005 }
2006
2007 static int tracing_open(struct inode *inode, struct file *file)
2008 {
2009 int ret;
2010
2011 __tracing_open(inode, file, &ret);
2012
2013 return ret;
2014 }
2015
2016 static int tracing_lt_open(struct inode *inode, struct file *file)
2017 {
2018 struct trace_iterator *iter;
2019 int ret;
2020
2021 iter = __tracing_open(inode, file, &ret);
2022
2023 if (!ret)
2024 iter->iter_flags |= TRACE_FILE_LAT_FMT;
2025
2026 return ret;
2027 }
2028
2029
2030 static void *
2031 t_next(struct seq_file *m, void *v, loff_t *pos)
2032 {
2033 struct tracer *t = m->private;
2034
2035 (*pos)++;
2036
2037 if (t)
2038 t = t->next;
2039
2040 m->private = t;
2041
2042 return t;
2043 }
2044
2045 static void *t_start(struct seq_file *m, loff_t *pos)
2046 {
2047 struct tracer *t = m->private;
2048 loff_t l = 0;
2049
2050 mutex_lock(&trace_types_lock);
2051 for (; t && l < *pos; t = t_next(m, t, &l))
2052 ;
2053
2054 return t;
2055 }
2056
2057 static void t_stop(struct seq_file *m, void *p)
2058 {
2059 mutex_unlock(&trace_types_lock);
2060 }
2061
2062 static int t_show(struct seq_file *m, void *v)
2063 {
2064 struct tracer *t = v;
2065
2066 if (!t)
2067 return 0;
2068
2069 seq_printf(m, "%s", t->name);
2070 if (t->next)
2071 seq_putc(m, ' ');
2072 else
2073 seq_putc(m, '\n');
2074
2075 return 0;
2076 }
2077
2078 static struct seq_operations show_traces_seq_ops = {
2079 .start = t_start,
2080 .next = t_next,
2081 .stop = t_stop,
2082 .show = t_show,
2083 };
2084
2085 static int show_traces_open(struct inode *inode, struct file *file)
2086 {
2087 int ret;
2088
2089 if (tracing_disabled)
2090 return -ENODEV;
2091
2092 ret = seq_open(file, &show_traces_seq_ops);
2093 if (!ret) {
2094 struct seq_file *m = file->private_data;
2095 m->private = trace_types;
2096 }
2097
2098 return ret;
2099 }
2100
2101 static struct file_operations tracing_fops = {
2102 .open = tracing_open,
2103 .read = seq_read,
2104 .llseek = seq_lseek,
2105 .release = tracing_release,
2106 };
2107
2108 static struct file_operations tracing_lt_fops = {
2109 .open = tracing_lt_open,
2110 .read = seq_read,
2111 .llseek = seq_lseek,
2112 .release = tracing_release,
2113 };
2114
2115 static struct file_operations show_traces_fops = {
2116 .open = show_traces_open,
2117 .read = seq_read,
2118 .release = seq_release,
2119 };
2120
2121 /*
2122 * Only trace on a CPU if the bitmask is set:
2123 */
2124 static cpumask_t tracing_cpumask = CPU_MASK_ALL;
2125
2126 /*
2127 * When tracing/tracing_cpu_mask is modified then this holds
2128 * the new bitmask we are about to install:
2129 */
2130 static cpumask_t tracing_cpumask_new;
2131
2132 /*
2133 * The tracer itself will not take this lock, but still we want
2134 * to provide a consistent cpumask to user-space:
2135 */
2136 static DEFINE_MUTEX(tracing_cpumask_update_lock);
2137
2138 /*
2139 * Temporary storage for the character representation of the
2140 * CPU bitmask (and one more byte for the newline):
2141 */
2142 static char mask_str[NR_CPUS + 1];
2143
2144 static ssize_t
2145 tracing_cpumask_read(struct file *filp, char __user *ubuf,
2146 size_t count, loff_t *ppos)
2147 {
2148 int len;
2149
2150 mutex_lock(&tracing_cpumask_update_lock);
2151
2152 len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
2153 if (count - len < 2) {
2154 count = -EINVAL;
2155 goto out_err;
2156 }
2157 len += sprintf(mask_str + len, "\n");
2158 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
2159
2160 out_err:
2161 mutex_unlock(&tracing_cpumask_update_lock);
2162
2163 return count;
2164 }
2165
2166 static ssize_t
2167 tracing_cpumask_write(struct file *filp, const char __user *ubuf,
2168 size_t count, loff_t *ppos)
2169 {
2170 int err, cpu;
2171
2172 mutex_lock(&tracing_cpumask_update_lock);
2173 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
2174 if (err)
2175 goto err_unlock;
2176
2177 raw_local_irq_disable();
2178 __raw_spin_lock(&ftrace_max_lock);
2179 for_each_tracing_cpu(cpu) {
2180 /*
2181 * Increase/decrease the disabled counter if we are
2182 * about to flip a bit in the cpumask:
2183 */
2184 if (cpu_isset(cpu, tracing_cpumask) &&
2185 !cpu_isset(cpu, tracing_cpumask_new)) {
2186 atomic_inc(&global_trace.data[cpu]->disabled);
2187 }
2188 if (!cpu_isset(cpu, tracing_cpumask) &&
2189 cpu_isset(cpu, tracing_cpumask_new)) {
2190 atomic_dec(&global_trace.data[cpu]->disabled);
2191 }
2192 }
2193 __raw_spin_unlock(&ftrace_max_lock);
2194 raw_local_irq_enable();
2195
2196 tracing_cpumask = tracing_cpumask_new;
2197
2198 mutex_unlock(&tracing_cpumask_update_lock);
2199
2200 return count;
2201
2202 err_unlock:
2203 mutex_unlock(&tracing_cpumask_update_lock);
2204
2205 return err;
2206 }
2207
2208 static struct file_operations tracing_cpumask_fops = {
2209 .open = tracing_open_generic,
2210 .read = tracing_cpumask_read,
2211 .write = tracing_cpumask_write,
2212 };
2213
2214 static ssize_t
2215 tracing_iter_ctrl_read(struct file *filp, char __user *ubuf,
2216 size_t cnt, loff_t *ppos)
2217 {
2218 char *buf;
2219 int r = 0;
2220 int len = 0;
2221 int i;
2222
2223 /* calulate max size */
2224 for (i = 0; trace_options[i]; i++) {
2225 len += strlen(trace_options[i]);
2226 len += 3; /* "no" and space */
2227 }
2228
2229 /* +2 for \n and \0 */
2230 buf = kmalloc(len + 2, GFP_KERNEL);
2231 if (!buf)
2232 return -ENOMEM;
2233
2234 for (i = 0; trace_options[i]; i++) {
2235 if (trace_flags & (1 << i))
2236 r += sprintf(buf + r, "%s ", trace_options[i]);
2237 else
2238 r += sprintf(buf + r, "no%s ", trace_options[i]);
2239 }
2240
2241 r += sprintf(buf + r, "\n");
2242 WARN_ON(r >= len + 2);
2243
2244 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2245
2246 kfree(buf);
2247
2248 return r;
2249 }
2250
2251 static ssize_t
2252 tracing_iter_ctrl_write(struct file *filp, const char __user *ubuf,
2253 size_t cnt, loff_t *ppos)
2254 {
2255 char buf[64];
2256 char *cmp = buf;
2257 int neg = 0;
2258 int i;
2259
2260 if (cnt >= sizeof(buf))
2261 return -EINVAL;
2262
2263 if (copy_from_user(&buf, ubuf, cnt))
2264 return -EFAULT;
2265
2266 buf[cnt] = 0;
2267
2268 if (strncmp(buf, "no", 2) == 0) {
2269 neg = 1;
2270 cmp += 2;
2271 }
2272
2273 for (i = 0; trace_options[i]; i++) {
2274 int len = strlen(trace_options[i]);
2275
2276 if (strncmp(cmp, trace_options[i], len) == 0) {
2277 if (neg)
2278 trace_flags &= ~(1 << i);
2279 else
2280 trace_flags |= (1 << i);
2281 break;
2282 }
2283 }
2284 /*
2285 * If no option could be set, return an error:
2286 */
2287 if (!trace_options[i])
2288 return -EINVAL;
2289
2290 filp->f_pos += cnt;
2291
2292 return cnt;
2293 }
2294
2295 static struct file_operations tracing_iter_fops = {
2296 .open = tracing_open_generic,
2297 .read = tracing_iter_ctrl_read,
2298 .write = tracing_iter_ctrl_write,
2299 };
2300
2301 static const char readme_msg[] =
2302 "tracing mini-HOWTO:\n\n"
2303 "# mkdir /debug\n"
2304 "# mount -t debugfs nodev /debug\n\n"
2305 "# cat /debug/tracing/available_tracers\n"
2306 "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
2307 "# cat /debug/tracing/current_tracer\n"
2308 "none\n"
2309 "# echo sched_switch > /debug/tracing/current_tracer\n"
2310 "# cat /debug/tracing/current_tracer\n"
2311 "sched_switch\n"
2312 "# cat /debug/tracing/iter_ctrl\n"
2313 "noprint-parent nosym-offset nosym-addr noverbose\n"
2314 "# echo print-parent > /debug/tracing/iter_ctrl\n"
2315 "# echo 1 > /debug/tracing/tracing_enabled\n"
2316 "# cat /debug/tracing/trace > /tmp/trace.txt\n"
2317 "echo 0 > /debug/tracing/tracing_enabled\n"
2318 ;
2319
2320 static ssize_t
2321 tracing_readme_read(struct file *filp, char __user *ubuf,
2322 size_t cnt, loff_t *ppos)
2323 {
2324 return simple_read_from_buffer(ubuf, cnt, ppos,
2325 readme_msg, strlen(readme_msg));
2326 }
2327
2328 static struct file_operations tracing_readme_fops = {
2329 .open = tracing_open_generic,
2330 .read = tracing_readme_read,
2331 };
2332
2333 static ssize_t
2334 tracing_ctrl_read(struct file *filp, char __user *ubuf,
2335 size_t cnt, loff_t *ppos)
2336 {
2337 struct trace_array *tr = filp->private_data;
2338 char buf[64];
2339 int r;
2340
2341 r = sprintf(buf, "%ld\n", tr->ctrl);
2342 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2343 }
2344
2345 static ssize_t
2346 tracing_ctrl_write(struct file *filp, const char __user *ubuf,
2347 size_t cnt, loff_t *ppos)
2348 {
2349 struct trace_array *tr = filp->private_data;
2350 char buf[64];
2351 long val;
2352 int ret;
2353
2354 if (cnt >= sizeof(buf))
2355 return -EINVAL;
2356
2357 if (copy_from_user(&buf, ubuf, cnt))
2358 return -EFAULT;
2359
2360 buf[cnt] = 0;
2361
2362 ret = strict_strtoul(buf, 10, &val);
2363 if (ret < 0)
2364 return ret;
2365
2366 val = !!val;
2367
2368 mutex_lock(&trace_types_lock);
2369 if (tr->ctrl ^ val) {
2370 if (val)
2371 tracer_enabled = 1;
2372 else
2373 tracer_enabled = 0;
2374
2375 tr->ctrl = val;
2376
2377 if (current_trace && current_trace->ctrl_update)
2378 current_trace->ctrl_update(tr);
2379 }
2380 mutex_unlock(&trace_types_lock);
2381
2382 filp->f_pos += cnt;
2383
2384 return cnt;
2385 }
2386
2387 static ssize_t
2388 tracing_set_trace_read(struct file *filp, char __user *ubuf,
2389 size_t cnt, loff_t *ppos)
2390 {
2391 char buf[max_tracer_type_len+2];
2392 int r;
2393
2394 mutex_lock(&trace_types_lock);
2395 if (current_trace)
2396 r = sprintf(buf, "%s\n", current_trace->name);
2397 else
2398 r = sprintf(buf, "\n");
2399 mutex_unlock(&trace_types_lock);
2400
2401 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2402 }
2403
2404 static int tracing_set_tracer(char *buf)
2405 {
2406 struct trace_array *tr = &global_trace;
2407 struct tracer *t;
2408 int ret = 0;
2409
2410 mutex_lock(&trace_types_lock);
2411 for (t = trace_types; t; t = t->next) {
2412 if (strcmp(t->name, buf) == 0)
2413 break;
2414 }
2415 if (!t) {
2416 ret = -EINVAL;
2417 goto out;
2418 }
2419 if (t == current_trace)
2420 goto out;
2421
2422 if (current_trace && current_trace->reset)
2423 current_trace->reset(tr);
2424
2425 current_trace = t;
2426 if (t->init)
2427 t->init(tr);
2428
2429 out:
2430 mutex_unlock(&trace_types_lock);
2431
2432 return ret;
2433 }
2434
2435 static ssize_t
2436 tracing_set_trace_write(struct file *filp, const char __user *ubuf,
2437 size_t cnt, loff_t *ppos)
2438 {
2439 char buf[max_tracer_type_len+1];
2440 int i;
2441 size_t ret;
2442
2443 if (cnt > max_tracer_type_len)
2444 cnt = max_tracer_type_len;
2445
2446 if (copy_from_user(&buf, ubuf, cnt))
2447 return -EFAULT;
2448
2449 buf[cnt] = 0;
2450
2451 /* strip ending whitespace. */
2452 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
2453 buf[i] = 0;
2454
2455 ret = tracing_set_tracer(buf);
2456 if (!ret)
2457 ret = cnt;
2458
2459 if (ret > 0)
2460 filp->f_pos += ret;
2461
2462 return ret;
2463 }
2464
2465 static ssize_t
2466 tracing_max_lat_read(struct file *filp, char __user *ubuf,
2467 size_t cnt, loff_t *ppos)
2468 {
2469 unsigned long *ptr = filp->private_data;
2470 char buf[64];
2471 int r;
2472
2473 r = snprintf(buf, sizeof(buf), "%ld\n",
2474 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
2475 if (r > sizeof(buf))
2476 r = sizeof(buf);
2477 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2478 }
2479
2480 static ssize_t
2481 tracing_max_lat_write(struct file *filp, const char __user *ubuf,
2482 size_t cnt, loff_t *ppos)
2483 {
2484 long *ptr = filp->private_data;
2485 char buf[64];
2486 long val;
2487 int ret;
2488
2489 if (cnt >= sizeof(buf))
2490 return -EINVAL;
2491
2492 if (copy_from_user(&buf, ubuf, cnt))
2493 return -EFAULT;
2494
2495 buf[cnt] = 0;
2496
2497 ret = strict_strtoul(buf, 10, &val);
2498 if (ret < 0)
2499 return ret;
2500
2501 *ptr = val * 1000;
2502
2503 return cnt;
2504 }
2505
2506 static atomic_t tracing_reader;
2507
2508 static int tracing_open_pipe(struct inode *inode, struct file *filp)
2509 {
2510 struct trace_iterator *iter;
2511
2512 if (tracing_disabled)
2513 return -ENODEV;
2514
2515 /* We only allow for reader of the pipe */
2516 if (atomic_inc_return(&tracing_reader) != 1) {
2517 atomic_dec(&tracing_reader);
2518 return -EBUSY;
2519 }
2520
2521 /* create a buffer to store the information to pass to userspace */
2522 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2523 if (!iter)
2524 return -ENOMEM;
2525
2526 mutex_lock(&trace_types_lock);
2527 iter->tr = &global_trace;
2528 iter->trace = current_trace;
2529 filp->private_data = iter;
2530
2531 if (iter->trace->pipe_open)
2532 iter->trace->pipe_open(iter);
2533 mutex_unlock(&trace_types_lock);
2534
2535 return 0;
2536 }
2537
2538 static int tracing_release_pipe(struct inode *inode, struct file *file)
2539 {
2540 struct trace_iterator *iter = file->private_data;
2541
2542 kfree(iter);
2543 atomic_dec(&tracing_reader);
2544
2545 return 0;
2546 }
2547
2548 static unsigned int
2549 tracing_poll_pipe(struct file *filp, poll_table *poll_table)
2550 {
2551 struct trace_iterator *iter = filp->private_data;
2552
2553 if (trace_flags & TRACE_ITER_BLOCK) {
2554 /*
2555 * Always select as readable when in blocking mode
2556 */
2557 return POLLIN | POLLRDNORM;
2558 } else {
2559 if (!trace_empty(iter))
2560 return POLLIN | POLLRDNORM;
2561 poll_wait(filp, &trace_wait, poll_table);
2562 if (!trace_empty(iter))
2563 return POLLIN | POLLRDNORM;
2564
2565 return 0;
2566 }
2567 }
2568
2569 /*
2570 * Consumer reader.
2571 */
2572 static ssize_t
2573 tracing_read_pipe(struct file *filp, char __user *ubuf,
2574 size_t cnt, loff_t *ppos)
2575 {
2576 struct trace_iterator *iter = filp->private_data;
2577 ssize_t sret;
2578
2579 /* return any leftover data */
2580 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
2581 if (sret != -EBUSY)
2582 return sret;
2583
2584 trace_seq_reset(&iter->seq);
2585
2586 mutex_lock(&trace_types_lock);
2587 if (iter->trace->read) {
2588 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
2589 if (sret)
2590 goto out;
2591 }
2592
2593 waitagain:
2594 sret = 0;
2595 while (trace_empty(iter)) {
2596
2597 if ((filp->f_flags & O_NONBLOCK)) {
2598 sret = -EAGAIN;
2599 goto out;
2600 }
2601
2602 /*
2603 * This is a make-shift waitqueue. The reason we don't use
2604 * an actual wait queue is because:
2605 * 1) we only ever have one waiter
2606 * 2) the tracing, traces all functions, we don't want
2607 * the overhead of calling wake_up and friends
2608 * (and tracing them too)
2609 * Anyway, this is really very primitive wakeup.
2610 */
2611 set_current_state(TASK_INTERRUPTIBLE);
2612 iter->tr->waiter = current;
2613
2614 mutex_unlock(&trace_types_lock);
2615
2616 /* sleep for 100 msecs, and try again. */
2617 schedule_timeout(HZ/10);
2618
2619 mutex_lock(&trace_types_lock);
2620
2621 iter->tr->waiter = NULL;
2622
2623 if (signal_pending(current)) {
2624 sret = -EINTR;
2625 goto out;
2626 }
2627
2628 if (iter->trace != current_trace)
2629 goto out;
2630
2631 /*
2632 * We block until we read something and tracing is disabled.
2633 * We still block if tracing is disabled, but we have never
2634 * read anything. This allows a user to cat this file, and
2635 * then enable tracing. But after we have read something,
2636 * we give an EOF when tracing is again disabled.
2637 *
2638 * iter->pos will be 0 if we haven't read anything.
2639 */
2640 if (!tracer_enabled && iter->pos)
2641 break;
2642
2643 continue;
2644 }
2645
2646 /* stop when tracing is finished */
2647 if (trace_empty(iter))
2648 goto out;
2649
2650 if (cnt >= PAGE_SIZE)
2651 cnt = PAGE_SIZE - 1;
2652
2653 /* reset all but tr, trace, and overruns */
2654 memset(&iter->seq, 0,
2655 sizeof(struct trace_iterator) -
2656 offsetof(struct trace_iterator, seq));
2657 iter->pos = -1;
2658
2659 while (find_next_entry_inc(iter) != NULL) {
2660 enum print_line_t ret;
2661 int len = iter->seq.len;
2662
2663 ret = print_trace_line(iter);
2664 if (ret == TRACE_TYPE_PARTIAL_LINE) {
2665 /* don't print partial lines */
2666 iter->seq.len = len;
2667 break;
2668 }
2669
2670 trace_consume(iter);
2671
2672 if (iter->seq.len >= cnt)
2673 break;
2674 }
2675
2676 /* Now copy what we have to the user */
2677 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
2678 if (iter->seq.readpos >= iter->seq.len)
2679 trace_seq_reset(&iter->seq);
2680
2681 /*
2682 * If there was nothing to send to user, inspite of consuming trace
2683 * entries, go back to wait for more entries.
2684 */
2685 if (sret == -EBUSY)
2686 goto waitagain;
2687
2688 out:
2689 mutex_unlock(&trace_types_lock);
2690
2691 return sret;
2692 }
2693
2694 static ssize_t
2695 tracing_entries_read(struct file *filp, char __user *ubuf,
2696 size_t cnt, loff_t *ppos)
2697 {
2698 struct trace_array *tr = filp->private_data;
2699 char buf[64];
2700 int r;
2701
2702 r = sprintf(buf, "%lu\n", tr->entries);
2703 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2704 }
2705
2706 static ssize_t
2707 tracing_entries_write(struct file *filp, const char __user *ubuf,
2708 size_t cnt, loff_t *ppos)
2709 {
2710 unsigned long val;
2711 char buf[64];
2712 int ret;
2713 struct trace_array *tr = filp->private_data;
2714
2715 if (cnt >= sizeof(buf))
2716 return -EINVAL;
2717
2718 if (copy_from_user(&buf, ubuf, cnt))
2719 return -EFAULT;
2720
2721 buf[cnt] = 0;
2722
2723 ret = strict_strtoul(buf, 10, &val);
2724 if (ret < 0)
2725 return ret;
2726
2727 /* must have at least 1 entry */
2728 if (!val)
2729 return -EINVAL;
2730
2731 mutex_lock(&trace_types_lock);
2732
2733 if (tr->ctrl) {
2734 cnt = -EBUSY;
2735 pr_info("ftrace: please disable tracing"
2736 " before modifying buffer size\n");
2737 goto out;
2738 }
2739
2740 if (val != global_trace.entries) {
2741 ret = ring_buffer_resize(global_trace.buffer, val);
2742 if (ret < 0) {
2743 cnt = ret;
2744 goto out;
2745 }
2746
2747 ret = ring_buffer_resize(max_tr.buffer, val);
2748 if (ret < 0) {
2749 int r;
2750 cnt = ret;
2751 r = ring_buffer_resize(global_trace.buffer,
2752 global_trace.entries);
2753 if (r < 0) {
2754 /* AARGH! We are left with different
2755 * size max buffer!!!! */
2756 WARN_ON(1);
2757 tracing_disabled = 1;
2758 }
2759 goto out;
2760 }
2761
2762 global_trace.entries = val;
2763 }
2764
2765 filp->f_pos += cnt;
2766
2767 /* If check pages failed, return ENOMEM */
2768 if (tracing_disabled)
2769 cnt = -ENOMEM;
2770 out:
2771 max_tr.entries = global_trace.entries;
2772 mutex_unlock(&trace_types_lock);
2773
2774 return cnt;
2775 }
2776
2777 static int mark_printk(const char *fmt, ...)
2778 {
2779 int ret;
2780 va_list args;
2781 va_start(args, fmt);
2782 ret = trace_vprintk(0, fmt, args);
2783 va_end(args);
2784 return ret;
2785 }
2786
2787 static ssize_t
2788 tracing_mark_write(struct file *filp, const char __user *ubuf,
2789 size_t cnt, loff_t *fpos)
2790 {
2791 char *buf;
2792 char *end;
2793 struct trace_array *tr = &global_trace;
2794
2795 if (!tr->ctrl || tracing_disabled)
2796 return -EINVAL;
2797
2798 if (cnt > TRACE_BUF_SIZE)
2799 cnt = TRACE_BUF_SIZE;
2800
2801 buf = kmalloc(cnt + 1, GFP_KERNEL);
2802 if (buf == NULL)
2803 return -ENOMEM;
2804
2805 if (copy_from_user(buf, ubuf, cnt)) {
2806 kfree(buf);
2807 return -EFAULT;
2808 }
2809
2810 /* Cut from the first nil or newline. */
2811 buf[cnt] = '\0';
2812 end = strchr(buf, '\n');
2813 if (end)
2814 *end = '\0';
2815
2816 cnt = mark_printk("%s\n", buf);
2817 kfree(buf);
2818 *fpos += cnt;
2819
2820 return cnt;
2821 }
2822
2823 static struct file_operations tracing_max_lat_fops = {
2824 .open = tracing_open_generic,
2825 .read = tracing_max_lat_read,
2826 .write = tracing_max_lat_write,
2827 };
2828
2829 static struct file_operations tracing_ctrl_fops = {
2830 .open = tracing_open_generic,
2831 .read = tracing_ctrl_read,
2832 .write = tracing_ctrl_write,
2833 };
2834
2835 static struct file_operations set_tracer_fops = {
2836 .open = tracing_open_generic,
2837 .read = tracing_set_trace_read,
2838 .write = tracing_set_trace_write,
2839 };
2840
2841 static struct file_operations tracing_pipe_fops = {
2842 .open = tracing_open_pipe,
2843 .poll = tracing_poll_pipe,
2844 .read = tracing_read_pipe,
2845 .release = tracing_release_pipe,
2846 };
2847
2848 static struct file_operations tracing_entries_fops = {
2849 .open = tracing_open_generic,
2850 .read = tracing_entries_read,
2851 .write = tracing_entries_write,
2852 };
2853
2854 static struct file_operations tracing_mark_fops = {
2855 .open = tracing_open_generic,
2856 .write = tracing_mark_write,
2857 };
2858
2859 #ifdef CONFIG_DYNAMIC_FTRACE
2860
2861 int __weak ftrace_arch_read_dyn_info(char *buf, int size)
2862 {
2863 return 0;
2864 }
2865
2866 static ssize_t
2867 tracing_read_dyn_info(struct file *filp, char __user *ubuf,
2868 size_t cnt, loff_t *ppos)
2869 {
2870 static char ftrace_dyn_info_buffer[1024];
2871 static DEFINE_MUTEX(dyn_info_mutex);
2872 unsigned long *p = filp->private_data;
2873 char *buf = ftrace_dyn_info_buffer;
2874 int size = ARRAY_SIZE(ftrace_dyn_info_buffer);
2875 int r;
2876
2877 mutex_lock(&dyn_info_mutex);
2878 r = sprintf(buf, "%ld ", *p);
2879
2880 r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r);
2881 buf[r++] = '\n';
2882
2883 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2884
2885 mutex_unlock(&dyn_info_mutex);
2886
2887 return r;
2888 }
2889
2890 static struct file_operations tracing_dyn_info_fops = {
2891 .open = tracing_open_generic,
2892 .read = tracing_read_dyn_info,
2893 };
2894 #endif
2895
2896 static struct dentry *d_tracer;
2897
2898 struct dentry *tracing_init_dentry(void)
2899 {
2900 static int once;
2901
2902 if (d_tracer)
2903 return d_tracer;
2904
2905 d_tracer = debugfs_create_dir("tracing", NULL);
2906
2907 if (!d_tracer && !once) {
2908 once = 1;
2909 pr_warning("Could not create debugfs directory 'tracing'\n");
2910 return NULL;
2911 }
2912
2913 return d_tracer;
2914 }
2915
2916 #ifdef CONFIG_FTRACE_SELFTEST
2917 /* Let selftest have access to static functions in this file */
2918 #include "trace_selftest.c"
2919 #endif
2920
2921 static __init int tracer_init_debugfs(void)
2922 {
2923 struct dentry *d_tracer;
2924 struct dentry *entry;
2925
2926 d_tracer = tracing_init_dentry();
2927
2928 entry = debugfs_create_file("tracing_enabled", 0644, d_tracer,
2929 &global_trace, &tracing_ctrl_fops);
2930 if (!entry)
2931 pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
2932
2933 entry = debugfs_create_file("iter_ctrl", 0644, d_tracer,
2934 NULL, &tracing_iter_fops);
2935 if (!entry)
2936 pr_warning("Could not create debugfs 'iter_ctrl' entry\n");
2937
2938 entry = debugfs_create_file("tracing_cpumask", 0644, d_tracer,
2939 NULL, &tracing_cpumask_fops);
2940 if (!entry)
2941 pr_warning("Could not create debugfs 'tracing_cpumask' entry\n");
2942
2943 entry = debugfs_create_file("latency_trace", 0444, d_tracer,
2944 &global_trace, &tracing_lt_fops);
2945 if (!entry)
2946 pr_warning("Could not create debugfs 'latency_trace' entry\n");
2947
2948 entry = debugfs_create_file("trace", 0444, d_tracer,
2949 &global_trace, &tracing_fops);
2950 if (!entry)
2951 pr_warning("Could not create debugfs 'trace' entry\n");
2952
2953 entry = debugfs_create_file("available_tracers", 0444, d_tracer,
2954 &global_trace, &show_traces_fops);
2955 if (!entry)
2956 pr_warning("Could not create debugfs 'available_tracers' entry\n");
2957
2958 entry = debugfs_create_file("current_tracer", 0444, d_tracer,
2959 &global_trace, &set_tracer_fops);
2960 if (!entry)
2961 pr_warning("Could not create debugfs 'current_tracer' entry\n");
2962
2963 entry = debugfs_create_file("tracing_max_latency", 0644, d_tracer,
2964 &tracing_max_latency,
2965 &tracing_max_lat_fops);
2966 if (!entry)
2967 pr_warning("Could not create debugfs "
2968 "'tracing_max_latency' entry\n");
2969
2970 entry = debugfs_create_file("tracing_thresh", 0644, d_tracer,
2971 &tracing_thresh, &tracing_max_lat_fops);
2972 if (!entry)
2973 pr_warning("Could not create debugfs "
2974 "'tracing_thresh' entry\n");
2975 entry = debugfs_create_file("README", 0644, d_tracer,
2976 NULL, &tracing_readme_fops);
2977 if (!entry)
2978 pr_warning("Could not create debugfs 'README' entry\n");
2979
2980 entry = debugfs_create_file("trace_pipe", 0644, d_tracer,
2981 NULL, &tracing_pipe_fops);
2982 if (!entry)
2983 pr_warning("Could not create debugfs "
2984 "'trace_pipe' entry\n");
2985
2986 entry = debugfs_create_file("trace_entries", 0644, d_tracer,
2987 &global_trace, &tracing_entries_fops);
2988 if (!entry)
2989 pr_warning("Could not create debugfs "
2990 "'trace_entries' entry\n");
2991
2992 entry = debugfs_create_file("trace_marker", 0220, d_tracer,
2993 NULL, &tracing_mark_fops);
2994 if (!entry)
2995 pr_warning("Could not create debugfs "
2996 "'trace_marker' entry\n");
2997
2998 #ifdef CONFIG_DYNAMIC_FTRACE
2999 entry = debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer,
3000 &ftrace_update_tot_cnt,
3001 &tracing_dyn_info_fops);
3002 if (!entry)
3003 pr_warning("Could not create debugfs "
3004 "'dyn_ftrace_total_info' entry\n");
3005 #endif
3006 #ifdef CONFIG_SYSPROF_TRACER
3007 init_tracer_sysprof_debugfs(d_tracer);
3008 #endif
3009 return 0;
3010 }
3011
3012 int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
3013 {
3014 static DEFINE_SPINLOCK(trace_buf_lock);
3015 static char trace_buf[TRACE_BUF_SIZE];
3016
3017 struct ring_buffer_event *event;
3018 struct trace_array *tr = &global_trace;
3019 struct trace_array_cpu *data;
3020 struct print_entry *entry;
3021 unsigned long flags, irq_flags;
3022 int cpu, len = 0, size, pc;
3023
3024 if (!tr->ctrl || tracing_disabled)
3025 return 0;
3026
3027 pc = preempt_count();
3028 preempt_disable_notrace();
3029 cpu = raw_smp_processor_id();
3030 data = tr->data[cpu];
3031
3032 if (unlikely(atomic_read(&data->disabled)))
3033 goto out;
3034
3035 spin_lock_irqsave(&trace_buf_lock, flags);
3036 len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);
3037
3038 len = min(len, TRACE_BUF_SIZE-1);
3039 trace_buf[len] = 0;
3040
3041 size = sizeof(*entry) + len + 1;
3042 event = ring_buffer_lock_reserve(tr->buffer, size, &irq_flags);
3043 if (!event)
3044 goto out_unlock;
3045 entry = ring_buffer_event_data(event);
3046 tracing_generic_entry_update(&entry->ent, flags, pc);
3047 entry->ent.type = TRACE_PRINT;
3048 entry->ip = ip;
3049
3050 memcpy(&entry->buf, trace_buf, len);
3051 entry->buf[len] = 0;
3052 ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
3053
3054 out_unlock:
3055 spin_unlock_irqrestore(&trace_buf_lock, flags);
3056
3057 out:
3058 preempt_enable_notrace();
3059
3060 return len;
3061 }
3062 EXPORT_SYMBOL_GPL(trace_vprintk);
3063
3064 int __ftrace_printk(unsigned long ip, const char *fmt, ...)
3065 {
3066 int ret;
3067 va_list ap;
3068
3069 if (!(trace_flags & TRACE_ITER_PRINTK))
3070 return 0;
3071
3072 va_start(ap, fmt);
3073 ret = trace_vprintk(ip, fmt, ap);
3074 va_end(ap);
3075 return ret;
3076 }
3077 EXPORT_SYMBOL_GPL(__ftrace_printk);
3078
3079 static int trace_panic_handler(struct notifier_block *this,
3080 unsigned long event, void *unused)
3081 {
3082 if (ftrace_dump_on_oops)
3083 ftrace_dump();
3084 return NOTIFY_OK;
3085 }
3086
3087 static struct notifier_block trace_panic_notifier = {
3088 .notifier_call = trace_panic_handler,
3089 .next = NULL,
3090 .priority = 150 /* priority: INT_MAX >= x >= 0 */
3091 };
3092
3093 static int trace_die_handler(struct notifier_block *self,
3094 unsigned long val,
3095 void *data)
3096 {
3097 switch (val) {
3098 case DIE_OOPS:
3099 if (ftrace_dump_on_oops)
3100 ftrace_dump();
3101 break;
3102 default:
3103 break;
3104 }
3105 return NOTIFY_OK;
3106 }
3107
3108 static struct notifier_block trace_die_notifier = {
3109 .notifier_call = trace_die_handler,
3110 .priority = 200
3111 };
3112
3113 /*
3114 * printk is set to max of 1024, we really don't need it that big.
3115 * Nothing should be printing 1000 characters anyway.
3116 */
3117 #define TRACE_MAX_PRINT 1000
3118
3119 /*
3120 * Define here KERN_TRACE so that we have one place to modify
3121 * it if we decide to change what log level the ftrace dump
3122 * should be at.
3123 */
3124 #define KERN_TRACE KERN_INFO
3125
3126 static void
3127 trace_printk_seq(struct trace_seq *s)
3128 {
3129 /* Probably should print a warning here. */
3130 if (s->len >= 1000)
3131 s->len = 1000;
3132
3133 /* should be zero ended, but we are paranoid. */
3134 s->buffer[s->len] = 0;
3135
3136 printk(KERN_TRACE "%s", s->buffer);
3137
3138 trace_seq_reset(s);
3139 }
3140
3141 void ftrace_dump(void)
3142 {
3143 static DEFINE_SPINLOCK(ftrace_dump_lock);
3144 /* use static because iter can be a bit big for the stack */
3145 static struct trace_iterator iter;
3146 static cpumask_t mask;
3147 static int dump_ran;
3148 unsigned long flags;
3149 int cnt = 0, cpu;
3150
3151 /* only one dump */
3152 spin_lock_irqsave(&ftrace_dump_lock, flags);
3153 if (dump_ran)
3154 goto out;
3155
3156 dump_ran = 1;
3157
3158 /* No turning back! */
3159 ftrace_kill();
3160
3161 for_each_tracing_cpu(cpu) {
3162 atomic_inc(&global_trace.data[cpu]->disabled);
3163 }
3164
3165 printk(KERN_TRACE "Dumping ftrace buffer:\n");
3166
3167 iter.tr = &global_trace;
3168 iter.trace = current_trace;
3169
3170 /*
3171 * We need to stop all tracing on all CPUS to read the
3172 * the next buffer. This is a bit expensive, but is
3173 * not done often. We fill all what we can read,
3174 * and then release the locks again.
3175 */
3176
3177 cpus_clear(mask);
3178
3179 while (!trace_empty(&iter)) {
3180
3181 if (!cnt)
3182 printk(KERN_TRACE "---------------------------------\n");
3183
3184 cnt++;
3185
3186 /* reset all but tr, trace, and overruns */
3187 memset(&iter.seq, 0,
3188 sizeof(struct trace_iterator) -
3189 offsetof(struct trace_iterator, seq));
3190 iter.iter_flags |= TRACE_FILE_LAT_FMT;
3191 iter.pos = -1;
3192
3193 if (find_next_entry_inc(&iter) != NULL) {
3194 print_trace_line(&iter);
3195 trace_consume(&iter);
3196 }
3197
3198 trace_printk_seq(&iter.seq);
3199 }
3200
3201 if (!cnt)
3202 printk(KERN_TRACE " (ftrace buffer empty)\n");
3203 else
3204 printk(KERN_TRACE "---------------------------------\n");
3205
3206 out:
3207 spin_unlock_irqrestore(&ftrace_dump_lock, flags);
3208 }
3209
3210 __init static int tracer_alloc_buffers(void)
3211 {
3212 struct trace_array_cpu *data;
3213 int i;
3214
3215 /* TODO: make the number of buffers hot pluggable with CPUS */
3216 tracing_buffer_mask = cpu_possible_map;
3217
3218 global_trace.buffer = ring_buffer_alloc(trace_buf_size,
3219 TRACE_BUFFER_FLAGS);
3220 if (!global_trace.buffer) {
3221 printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
3222 WARN_ON(1);
3223 return 0;
3224 }
3225 global_trace.entries = ring_buffer_size(global_trace.buffer);
3226
3227 #ifdef CONFIG_TRACER_MAX_TRACE
3228 max_tr.buffer = ring_buffer_alloc(trace_buf_size,
3229 TRACE_BUFFER_FLAGS);
3230 if (!max_tr.buffer) {
3231 printk(KERN_ERR "tracer: failed to allocate max ring buffer!\n");
3232 WARN_ON(1);
3233 ring_buffer_free(global_trace.buffer);
3234 return 0;
3235 }
3236 max_tr.entries = ring_buffer_size(max_tr.buffer);
3237 WARN_ON(max_tr.entries != global_trace.entries);
3238 #endif
3239
3240 /* Allocate the first page for all buffers */
3241 for_each_tracing_cpu(i) {
3242 data = global_trace.data[i] = &per_cpu(global_trace_cpu, i);
3243 max_tr.data[i] = &per_cpu(max_data, i);
3244 }
3245
3246 trace_init_cmdlines();
3247
3248 register_tracer(&nop_trace);
3249 #ifdef CONFIG_BOOT_TRACER
3250 register_tracer(&boot_tracer);
3251 current_trace = &boot_tracer;
3252 current_trace->init(&global_trace);
3253 #else
3254 current_trace = &nop_trace;
3255 #endif
3256
3257 /* All seems OK, enable tracing */
3258 global_trace.ctrl = tracer_enabled;
3259 tracing_disabled = 0;
3260
3261 atomic_notifier_chain_register(&panic_notifier_list,
3262 &trace_panic_notifier);
3263
3264 register_die_notifier(&trace_die_notifier);
3265
3266 return 0;
3267 }
3268 early_initcall(tracer_alloc_buffers);
3269 fs_initcall(tracer_init_debugfs);
Linus' kernel tree