projects/linux·blob v2.6.28 · refs

3235 lines · 71.8 KiB

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