Merge branches 'tracing/ftrace', 'tracing/kprobes', 'tracing/tasks' and 'linus' into...
[GitHub/exynos8895/android_kernel_samsung_universal8895.git] / kernel / trace / trace.c
1 /*
2 * ring buffer based function tracer
3 *
4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
6 *
7 * Originally taken from the RT patch by:
8 * Arnaldo Carvalho de Melo <acme@redhat.com>
9 *
10 * Based on code from the latency_tracer, that is:
11 * Copyright (C) 2004-2006 Ingo Molnar
12 * Copyright (C) 2004 William Lee Irwin III
13 */
14 #include <linux/ring_buffer.h>
15 #include <linux/utsrelease.h>
16 #include <linux/stacktrace.h>
17 #include <linux/writeback.h>
18 #include <linux/kallsyms.h>
19 #include <linux/seq_file.h>
20 #include <linux/notifier.h>
21 #include <linux/irqflags.h>
22 #include <linux/debugfs.h>
23 #include <linux/pagemap.h>
24 #include <linux/hardirq.h>
25 #include <linux/linkage.h>
26 #include <linux/uaccess.h>
27 #include <linux/kprobes.h>
28 #include <linux/ftrace.h>
29 #include <linux/module.h>
30 #include <linux/percpu.h>
31 #include <linux/splice.h>
32 #include <linux/kdebug.h>
33 #include <linux/ctype.h>
34 #include <linux/init.h>
35 #include <linux/poll.h>
36 #include <linux/gfp.h>
37 #include <linux/fs.h>
38
39 #include "trace.h"
40 #include "trace_output.h"
41
42 #define TRACE_BUFFER_FLAGS (RB_FL_OVERWRITE)
43
44 unsigned long __read_mostly tracing_max_latency;
45 unsigned long __read_mostly tracing_thresh;
46
47 /*
48 * On boot up, the ring buffer is set to the minimum size, so that
49 * we do not waste memory on systems that are not using tracing.
50 */
51 static int ring_buffer_expanded;
52
53 /*
54 * We need to change this state when a selftest is running.
55 * A selftest will lurk into the ring-buffer to count the
56 * entries inserted during the selftest although some concurrent
57 * insertions into the ring-buffer such as trace_printk could occurred
58 * at the same time, giving false positive or negative results.
59 */
60 static bool __read_mostly tracing_selftest_running;
61
62 /*
63 * If a tracer is running, we do not want to run SELFTEST.
64 */
65 static bool __read_mostly tracing_selftest_disabled;
66
67 /* For tracers that don't implement custom flags */
68 static struct tracer_opt dummy_tracer_opt[] = {
69 { }
70 };
71
72 static struct tracer_flags dummy_tracer_flags = {
73 .val = 0,
74 .opts = dummy_tracer_opt
75 };
76
77 static int dummy_set_flag(u32 old_flags, u32 bit, int set)
78 {
79 return 0;
80 }
81
82 /*
83 * Kill all tracing for good (never come back).
84 * It is initialized to 1 but will turn to zero if the initialization
85 * of the tracer is successful. But that is the only place that sets
86 * this back to zero.
87 */
88 static int tracing_disabled = 1;
89
90 static DEFINE_PER_CPU(local_t, ftrace_cpu_disabled);
91
92 static inline void ftrace_disable_cpu(void)
93 {
94 preempt_disable();
95 local_inc(&__get_cpu_var(ftrace_cpu_disabled));
96 }
97
98 static inline void ftrace_enable_cpu(void)
99 {
100 local_dec(&__get_cpu_var(ftrace_cpu_disabled));
101 preempt_enable();
102 }
103
104 static cpumask_var_t __read_mostly tracing_buffer_mask;
105
106 /* Define which cpu buffers are currently read in trace_pipe */
107 static cpumask_var_t tracing_reader_cpumask;
108
109 #define for_each_tracing_cpu(cpu) \
110 for_each_cpu(cpu, tracing_buffer_mask)
111
112 /*
113 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
114 *
115 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
116 * is set, then ftrace_dump is called. This will output the contents
117 * of the ftrace buffers to the console. This is very useful for
118 * capturing traces that lead to crashes and outputing it to a
119 * serial console.
120 *
121 * It is default off, but you can enable it with either specifying
122 * "ftrace_dump_on_oops" in the kernel command line, or setting
123 * /proc/sys/kernel/ftrace_dump_on_oops to true.
124 */
125 int ftrace_dump_on_oops;
126
127 static int tracing_set_tracer(const char *buf);
128
129 #define BOOTUP_TRACER_SIZE 100
130 static char bootup_tracer_buf[BOOTUP_TRACER_SIZE] __initdata;
131 static char *default_bootup_tracer;
132
133 static int __init set_ftrace(char *str)
134 {
135 strncpy(bootup_tracer_buf, str, BOOTUP_TRACER_SIZE);
136 default_bootup_tracer = bootup_tracer_buf;
137 /* We are using ftrace early, expand it */
138 ring_buffer_expanded = 1;
139 return 1;
140 }
141 __setup("ftrace=", set_ftrace);
142
143 static int __init set_ftrace_dump_on_oops(char *str)
144 {
145 ftrace_dump_on_oops = 1;
146 return 1;
147 }
148 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
149
150 long
151 ns2usecs(cycle_t nsec)
152 {
153 nsec += 500;
154 do_div(nsec, 1000);
155 return nsec;
156 }
157
158 /*
159 * The global_trace is the descriptor that holds the tracing
160 * buffers for the live tracing. For each CPU, it contains
161 * a link list of pages that will store trace entries. The
162 * page descriptor of the pages in the memory is used to hold
163 * the link list by linking the lru item in the page descriptor
164 * to each of the pages in the buffer per CPU.
165 *
166 * For each active CPU there is a data field that holds the
167 * pages for the buffer for that CPU. Each CPU has the same number
168 * of pages allocated for its buffer.
169 */
170 static struct trace_array global_trace;
171
172 static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
173
174 cycle_t ftrace_now(int cpu)
175 {
176 u64 ts;
177
178 /* Early boot up does not have a buffer yet */
179 if (!global_trace.buffer)
180 return trace_clock_local();
181
182 ts = ring_buffer_time_stamp(global_trace.buffer, cpu);
183 ring_buffer_normalize_time_stamp(global_trace.buffer, cpu, &ts);
184
185 return ts;
186 }
187
188 /*
189 * The max_tr is used to snapshot the global_trace when a maximum
190 * latency is reached. Some tracers will use this to store a maximum
191 * trace while it continues examining live traces.
192 *
193 * The buffers for the max_tr are set up the same as the global_trace.
194 * When a snapshot is taken, the link list of the max_tr is swapped
195 * with the link list of the global_trace and the buffers are reset for
196 * the global_trace so the tracing can continue.
197 */
198 static struct trace_array max_tr;
199
200 static DEFINE_PER_CPU(struct trace_array_cpu, max_data);
201
202 /* tracer_enabled is used to toggle activation of a tracer */
203 static int tracer_enabled = 1;
204
205 /**
206 * tracing_is_enabled - return tracer_enabled status
207 *
208 * This function is used by other tracers to know the status
209 * of the tracer_enabled flag. Tracers may use this function
210 * to know if it should enable their features when starting
211 * up. See irqsoff tracer for an example (start_irqsoff_tracer).
212 */
213 int tracing_is_enabled(void)
214 {
215 return tracer_enabled;
216 }
217
218 /*
219 * trace_buf_size is the size in bytes that is allocated
220 * for a buffer. Note, the number of bytes is always rounded
221 * to page size.
222 *
223 * This number is purposely set to a low number of 16384.
224 * If the dump on oops happens, it will be much appreciated
225 * to not have to wait for all that output. Anyway this can be
226 * boot time and run time configurable.
227 */
228 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
229
230 static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
231
232 /* trace_types holds a link list of available tracers. */
233 static struct tracer *trace_types __read_mostly;
234
235 /* current_trace points to the tracer that is currently active */
236 static struct tracer *current_trace __read_mostly;
237
238 /*
239 * max_tracer_type_len is used to simplify the allocating of
240 * buffers to read userspace tracer names. We keep track of
241 * the longest tracer name registered.
242 */
243 static int max_tracer_type_len;
244
245 /*
246 * trace_types_lock is used to protect the trace_types list.
247 * This lock is also used to keep user access serialized.
248 * Accesses from userspace will grab this lock while userspace
249 * activities happen inside the kernel.
250 */
251 static DEFINE_MUTEX(trace_types_lock);
252
253 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
254 static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
255
256 /* trace_flags holds trace_options default values */
257 unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
258 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO;
259
260 /**
261 * trace_wake_up - wake up tasks waiting for trace input
262 *
263 * Simply wakes up any task that is blocked on the trace_wait
264 * queue. These is used with trace_poll for tasks polling the trace.
265 */
266 void trace_wake_up(void)
267 {
268 /*
269 * The runqueue_is_locked() can fail, but this is the best we
270 * have for now:
271 */
272 if (!(trace_flags & TRACE_ITER_BLOCK) && !runqueue_is_locked())
273 wake_up(&trace_wait);
274 }
275
276 static int __init set_buf_size(char *str)
277 {
278 unsigned long buf_size;
279 int ret;
280
281 if (!str)
282 return 0;
283 ret = strict_strtoul(str, 0, &buf_size);
284 /* nr_entries can not be zero */
285 if (ret < 0 || buf_size == 0)
286 return 0;
287 trace_buf_size = buf_size;
288 return 1;
289 }
290 __setup("trace_buf_size=", set_buf_size);
291
292 unsigned long nsecs_to_usecs(unsigned long nsecs)
293 {
294 return nsecs / 1000;
295 }
296
297 /* These must match the bit postions in trace_iterator_flags */
298 static const char *trace_options[] = {
299 "print-parent",
300 "sym-offset",
301 "sym-addr",
302 "verbose",
303 "raw",
304 "hex",
305 "bin",
306 "block",
307 "stacktrace",
308 "sched-tree",
309 "trace_printk",
310 "ftrace_preempt",
311 "branch",
312 "annotate",
313 "userstacktrace",
314 "sym-userobj",
315 "printk-msg-only",
316 "context-info",
317 "latency-format",
318 "global-clock",
319 NULL
320 };
321
322 /*
323 * ftrace_max_lock is used to protect the swapping of buffers
324 * when taking a max snapshot. The buffers themselves are
325 * protected by per_cpu spinlocks. But the action of the swap
326 * needs its own lock.
327 *
328 * This is defined as a raw_spinlock_t in order to help
329 * with performance when lockdep debugging is enabled.
330 */
331 static raw_spinlock_t ftrace_max_lock =
332 (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
333
334 /*
335 * Copy the new maximum trace into the separate maximum-trace
336 * structure. (this way the maximum trace is permanently saved,
337 * for later retrieval via /debugfs/tracing/latency_trace)
338 */
339 static void
340 __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
341 {
342 struct trace_array_cpu *data = tr->data[cpu];
343
344 max_tr.cpu = cpu;
345 max_tr.time_start = data->preempt_timestamp;
346
347 data = max_tr.data[cpu];
348 data->saved_latency = tracing_max_latency;
349
350 memcpy(data->comm, tsk->comm, TASK_COMM_LEN);
351 data->pid = tsk->pid;
352 data->uid = task_uid(tsk);
353 data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
354 data->policy = tsk->policy;
355 data->rt_priority = tsk->rt_priority;
356
357 /* record this tasks comm */
358 tracing_record_cmdline(tsk);
359 }
360
361 ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
362 {
363 int len;
364 int ret;
365
366 if (!cnt)
367 return 0;
368
369 if (s->len <= s->readpos)
370 return -EBUSY;
371
372 len = s->len - s->readpos;
373 if (cnt > len)
374 cnt = len;
375 ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
376 if (ret == cnt)
377 return -EFAULT;
378
379 cnt -= ret;
380
381 s->readpos += cnt;
382 return cnt;
383 }
384
385 ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
386 {
387 int len;
388 void *ret;
389
390 if (s->len <= s->readpos)
391 return -EBUSY;
392
393 len = s->len - s->readpos;
394 if (cnt > len)
395 cnt = len;
396 ret = memcpy(buf, s->buffer + s->readpos, cnt);
397 if (!ret)
398 return -EFAULT;
399
400 s->readpos += cnt;
401 return cnt;
402 }
403
404 static void
405 trace_print_seq(struct seq_file *m, struct trace_seq *s)
406 {
407 int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
408
409 s->buffer[len] = 0;
410 seq_puts(m, s->buffer);
411
412 trace_seq_init(s);
413 }
414
415 /**
416 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
417 * @tr: tracer
418 * @tsk: the task with the latency
419 * @cpu: The cpu that initiated the trace.
420 *
421 * Flip the buffers between the @tr and the max_tr and record information
422 * about which task was the cause of this latency.
423 */
424 void
425 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
426 {
427 struct ring_buffer *buf = tr->buffer;
428
429 WARN_ON_ONCE(!irqs_disabled());
430 __raw_spin_lock(&ftrace_max_lock);
431
432 tr->buffer = max_tr.buffer;
433 max_tr.buffer = buf;
434
435 ftrace_disable_cpu();
436 ring_buffer_reset(tr->buffer);
437 ftrace_enable_cpu();
438
439 __update_max_tr(tr, tsk, cpu);
440 __raw_spin_unlock(&ftrace_max_lock);
441 }
442
443 /**
444 * update_max_tr_single - only copy one trace over, and reset the rest
445 * @tr - tracer
446 * @tsk - task with the latency
447 * @cpu - the cpu of the buffer to copy.
448 *
449 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
450 */
451 void
452 update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
453 {
454 int ret;
455
456 WARN_ON_ONCE(!irqs_disabled());
457 __raw_spin_lock(&ftrace_max_lock);
458
459 ftrace_disable_cpu();
460
461 ring_buffer_reset(max_tr.buffer);
462 ret = ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu);
463
464 ftrace_enable_cpu();
465
466 WARN_ON_ONCE(ret && ret != -EAGAIN);
467
468 __update_max_tr(tr, tsk, cpu);
469 __raw_spin_unlock(&ftrace_max_lock);
470 }
471
472 /**
473 * register_tracer - register a tracer with the ftrace system.
474 * @type - the plugin for the tracer
475 *
476 * Register a new plugin tracer.
477 */
478 int register_tracer(struct tracer *type)
479 __releases(kernel_lock)
480 __acquires(kernel_lock)
481 {
482 struct tracer *t;
483 int len;
484 int ret = 0;
485
486 if (!type->name) {
487 pr_info("Tracer must have a name\n");
488 return -1;
489 }
490
491 /*
492 * When this gets called we hold the BKL which means that
493 * preemption is disabled. Various trace selftests however
494 * need to disable and enable preemption for successful tests.
495 * So we drop the BKL here and grab it after the tests again.
496 */
497 unlock_kernel();
498 mutex_lock(&trace_types_lock);
499
500 tracing_selftest_running = true;
501
502 for (t = trace_types; t; t = t->next) {
503 if (strcmp(type->name, t->name) == 0) {
504 /* already found */
505 pr_info("Trace %s already registered\n",
506 type->name);
507 ret = -1;
508 goto out;
509 }
510 }
511
512 if (!type->set_flag)
513 type->set_flag = &dummy_set_flag;
514 if (!type->flags)
515 type->flags = &dummy_tracer_flags;
516 else
517 if (!type->flags->opts)
518 type->flags->opts = dummy_tracer_opt;
519 if (!type->wait_pipe)
520 type->wait_pipe = default_wait_pipe;
521
522
523 #ifdef CONFIG_FTRACE_STARTUP_TEST
524 if (type->selftest && !tracing_selftest_disabled) {
525 struct tracer *saved_tracer = current_trace;
526 struct trace_array *tr = &global_trace;
527 int i;
528
529 /*
530 * Run a selftest on this tracer.
531 * Here we reset the trace buffer, and set the current
532 * tracer to be this tracer. The tracer can then run some
533 * internal tracing to verify that everything is in order.
534 * If we fail, we do not register this tracer.
535 */
536 for_each_tracing_cpu(i)
537 tracing_reset(tr, i);
538
539 current_trace = type;
540 /* the test is responsible for initializing and enabling */
541 pr_info("Testing tracer %s: ", type->name);
542 ret = type->selftest(type, tr);
543 /* the test is responsible for resetting too */
544 current_trace = saved_tracer;
545 if (ret) {
546 printk(KERN_CONT "FAILED!\n");
547 goto out;
548 }
549 /* Only reset on passing, to avoid touching corrupted buffers */
550 for_each_tracing_cpu(i)
551 tracing_reset(tr, i);
552
553 printk(KERN_CONT "PASSED\n");
554 }
555 #endif
556
557 type->next = trace_types;
558 trace_types = type;
559 len = strlen(type->name);
560 if (len > max_tracer_type_len)
561 max_tracer_type_len = len;
562
563 out:
564 tracing_selftest_running = false;
565 mutex_unlock(&trace_types_lock);
566
567 if (ret || !default_bootup_tracer)
568 goto out_unlock;
569
570 if (strncmp(default_bootup_tracer, type->name, BOOTUP_TRACER_SIZE))
571 goto out_unlock;
572
573 printk(KERN_INFO "Starting tracer '%s'\n", type->name);
574 /* Do we want this tracer to start on bootup? */
575 tracing_set_tracer(type->name);
576 default_bootup_tracer = NULL;
577 /* disable other selftests, since this will break it. */
578 tracing_selftest_disabled = 1;
579 #ifdef CONFIG_FTRACE_STARTUP_TEST
580 printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
581 type->name);
582 #endif
583
584 out_unlock:
585 lock_kernel();
586 return ret;
587 }
588
589 void unregister_tracer(struct tracer *type)
590 {
591 struct tracer **t;
592 int len;
593
594 mutex_lock(&trace_types_lock);
595 for (t = &trace_types; *t; t = &(*t)->next) {
596 if (*t == type)
597 goto found;
598 }
599 pr_info("Trace %s not registered\n", type->name);
600 goto out;
601
602 found:
603 *t = (*t)->next;
604
605 if (type == current_trace && tracer_enabled) {
606 tracer_enabled = 0;
607 tracing_stop();
608 if (current_trace->stop)
609 current_trace->stop(&global_trace);
610 current_trace = &nop_trace;
611 }
612
613 if (strlen(type->name) != max_tracer_type_len)
614 goto out;
615
616 max_tracer_type_len = 0;
617 for (t = &trace_types; *t; t = &(*t)->next) {
618 len = strlen((*t)->name);
619 if (len > max_tracer_type_len)
620 max_tracer_type_len = len;
621 }
622 out:
623 mutex_unlock(&trace_types_lock);
624 }
625
626 void tracing_reset(struct trace_array *tr, int cpu)
627 {
628 ftrace_disable_cpu();
629 ring_buffer_reset_cpu(tr->buffer, cpu);
630 ftrace_enable_cpu();
631 }
632
633 void tracing_reset_online_cpus(struct trace_array *tr)
634 {
635 int cpu;
636
637 tr->time_start = ftrace_now(tr->cpu);
638
639 for_each_online_cpu(cpu)
640 tracing_reset(tr, cpu);
641 }
642
643 #define SAVED_CMDLINES 128
644 #define NO_CMDLINE_MAP UINT_MAX
645 static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
646 static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
647 static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
648 static int cmdline_idx;
649 static raw_spinlock_t trace_cmdline_lock = __RAW_SPIN_LOCK_UNLOCKED;
650
651 /* temporary disable recording */
652 static atomic_t trace_record_cmdline_disabled __read_mostly;
653
654 static void trace_init_cmdlines(void)
655 {
656 memset(&map_pid_to_cmdline, NO_CMDLINE_MAP, sizeof(map_pid_to_cmdline));
657 memset(&map_cmdline_to_pid, NO_CMDLINE_MAP, sizeof(map_cmdline_to_pid));
658 cmdline_idx = 0;
659 }
660
661 static int trace_stop_count;
662 static DEFINE_SPINLOCK(tracing_start_lock);
663
664 /**
665 * ftrace_off_permanent - disable all ftrace code permanently
666 *
667 * This should only be called when a serious anomally has
668 * been detected. This will turn off the function tracing,
669 * ring buffers, and other tracing utilites. It takes no
670 * locks and can be called from any context.
671 */
672 void ftrace_off_permanent(void)
673 {
674 tracing_disabled = 1;
675 ftrace_stop();
676 tracing_off_permanent();
677 }
678
679 /**
680 * tracing_start - quick start of the tracer
681 *
682 * If tracing is enabled but was stopped by tracing_stop,
683 * this will start the tracer back up.
684 */
685 void tracing_start(void)
686 {
687 struct ring_buffer *buffer;
688 unsigned long flags;
689
690 if (tracing_disabled)
691 return;
692
693 spin_lock_irqsave(&tracing_start_lock, flags);
694 if (--trace_stop_count) {
695 if (trace_stop_count < 0) {
696 /* Someone screwed up their debugging */
697 WARN_ON_ONCE(1);
698 trace_stop_count = 0;
699 }
700 goto out;
701 }
702
703
704 buffer = global_trace.buffer;
705 if (buffer)
706 ring_buffer_record_enable(buffer);
707
708 buffer = max_tr.buffer;
709 if (buffer)
710 ring_buffer_record_enable(buffer);
711
712 ftrace_start();
713 out:
714 spin_unlock_irqrestore(&tracing_start_lock, flags);
715 }
716
717 /**
718 * tracing_stop - quick stop of the tracer
719 *
720 * Light weight way to stop tracing. Use in conjunction with
721 * tracing_start.
722 */
723 void tracing_stop(void)
724 {
725 struct ring_buffer *buffer;
726 unsigned long flags;
727
728 ftrace_stop();
729 spin_lock_irqsave(&tracing_start_lock, flags);
730 if (trace_stop_count++)
731 goto out;
732
733 buffer = global_trace.buffer;
734 if (buffer)
735 ring_buffer_record_disable(buffer);
736
737 buffer = max_tr.buffer;
738 if (buffer)
739 ring_buffer_record_disable(buffer);
740
741 out:
742 spin_unlock_irqrestore(&tracing_start_lock, flags);
743 }
744
745 void trace_stop_cmdline_recording(void);
746
747 static void trace_save_cmdline(struct task_struct *tsk)
748 {
749 unsigned pid, idx;
750
751 if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
752 return;
753
754 /*
755 * It's not the end of the world if we don't get
756 * the lock, but we also don't want to spin
757 * nor do we want to disable interrupts,
758 * so if we miss here, then better luck next time.
759 */
760 if (!__raw_spin_trylock(&trace_cmdline_lock))
761 return;
762
763 idx = map_pid_to_cmdline[tsk->pid];
764 if (idx == NO_CMDLINE_MAP) {
765 idx = (cmdline_idx + 1) % SAVED_CMDLINES;
766
767 /*
768 * Check whether the cmdline buffer at idx has a pid
769 * mapped. We are going to overwrite that entry so we
770 * need to clear the map_pid_to_cmdline. Otherwise we
771 * would read the new comm for the old pid.
772 */
773 pid = map_cmdline_to_pid[idx];
774 if (pid != NO_CMDLINE_MAP)
775 map_pid_to_cmdline[pid] = NO_CMDLINE_MAP;
776
777 map_cmdline_to_pid[idx] = tsk->pid;
778 map_pid_to_cmdline[tsk->pid] = idx;
779
780 cmdline_idx = idx;
781 }
782
783 memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
784
785 __raw_spin_unlock(&trace_cmdline_lock);
786 }
787
788 void trace_find_cmdline(int pid, char comm[])
789 {
790 unsigned map;
791
792 if (!pid) {
793 strcpy(comm, "<idle>");
794 return;
795 }
796
797 if (pid > PID_MAX_DEFAULT) {
798 strcpy(comm, "<...>");
799 return;
800 }
801
802 __raw_spin_lock(&trace_cmdline_lock);
803 map = map_pid_to_cmdline[pid];
804 if (map != NO_CMDLINE_MAP)
805 strcpy(comm, saved_cmdlines[map]);
806 else
807 strcpy(comm, "<...>");
808
809 __raw_spin_unlock(&trace_cmdline_lock);
810 }
811
812 void tracing_record_cmdline(struct task_struct *tsk)
813 {
814 if (atomic_read(&trace_record_cmdline_disabled) || !tracer_enabled ||
815 !tracing_is_on())
816 return;
817
818 trace_save_cmdline(tsk);
819 }
820
821 void
822 tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
823 int pc)
824 {
825 struct task_struct *tsk = current;
826
827 entry->preempt_count = pc & 0xff;
828 entry->pid = (tsk) ? tsk->pid : 0;
829 entry->tgid = (tsk) ? tsk->tgid : 0;
830 entry->flags =
831 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
832 (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
833 #else
834 TRACE_FLAG_IRQS_NOSUPPORT |
835 #endif
836 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
837 ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
838 (need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
839 }
840
841 struct ring_buffer_event *trace_buffer_lock_reserve(struct trace_array *tr,
842 unsigned char type,
843 unsigned long len,
844 unsigned long flags, int pc)
845 {
846 struct ring_buffer_event *event;
847
848 event = ring_buffer_lock_reserve(tr->buffer, len);
849 if (event != NULL) {
850 struct trace_entry *ent = ring_buffer_event_data(event);
851
852 tracing_generic_entry_update(ent, flags, pc);
853 ent->type = type;
854 }
855
856 return event;
857 }
858 static void ftrace_trace_stack(struct trace_array *tr,
859 unsigned long flags, int skip, int pc);
860 static void ftrace_trace_userstack(struct trace_array *tr,
861 unsigned long flags, int pc);
862
863 void trace_buffer_unlock_commit(struct trace_array *tr,
864 struct ring_buffer_event *event,
865 unsigned long flags, int pc)
866 {
867 ring_buffer_unlock_commit(tr->buffer, event);
868
869 ftrace_trace_stack(tr, flags, 6, pc);
870 ftrace_trace_userstack(tr, flags, pc);
871 trace_wake_up();
872 }
873
874 struct ring_buffer_event *
875 trace_current_buffer_lock_reserve(unsigned char type, unsigned long len,
876 unsigned long flags, int pc)
877 {
878 return trace_buffer_lock_reserve(&global_trace,
879 type, len, flags, pc);
880 }
881
882 void trace_current_buffer_unlock_commit(struct ring_buffer_event *event,
883 unsigned long flags, int pc)
884 {
885 return trace_buffer_unlock_commit(&global_trace, event, flags, pc);
886 }
887
888 void
889 trace_function(struct trace_array *tr,
890 unsigned long ip, unsigned long parent_ip, unsigned long flags,
891 int pc)
892 {
893 struct ring_buffer_event *event;
894 struct ftrace_entry *entry;
895
896 /* If we are reading the ring buffer, don't trace */
897 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
898 return;
899
900 event = trace_buffer_lock_reserve(tr, TRACE_FN, sizeof(*entry),
901 flags, pc);
902 if (!event)
903 return;
904 entry = ring_buffer_event_data(event);
905 entry->ip = ip;
906 entry->parent_ip = parent_ip;
907 ring_buffer_unlock_commit(tr->buffer, event);
908 }
909
910 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
911 static void __trace_graph_entry(struct trace_array *tr,
912 struct ftrace_graph_ent *trace,
913 unsigned long flags,
914 int pc)
915 {
916 struct ring_buffer_event *event;
917 struct ftrace_graph_ent_entry *entry;
918
919 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
920 return;
921
922 event = trace_buffer_lock_reserve(&global_trace, TRACE_GRAPH_ENT,
923 sizeof(*entry), flags, pc);
924 if (!event)
925 return;
926 entry = ring_buffer_event_data(event);
927 entry->graph_ent = *trace;
928 ring_buffer_unlock_commit(global_trace.buffer, event);
929 }
930
931 static void __trace_graph_return(struct trace_array *tr,
932 struct ftrace_graph_ret *trace,
933 unsigned long flags,
934 int pc)
935 {
936 struct ring_buffer_event *event;
937 struct ftrace_graph_ret_entry *entry;
938
939 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
940 return;
941
942 event = trace_buffer_lock_reserve(&global_trace, TRACE_GRAPH_RET,
943 sizeof(*entry), flags, pc);
944 if (!event)
945 return;
946 entry = ring_buffer_event_data(event);
947 entry->ret = *trace;
948 ring_buffer_unlock_commit(global_trace.buffer, event);
949 }
950 #endif
951
952 void
953 ftrace(struct trace_array *tr, struct trace_array_cpu *data,
954 unsigned long ip, unsigned long parent_ip, unsigned long flags,
955 int pc)
956 {
957 if (likely(!atomic_read(&data->disabled)))
958 trace_function(tr, ip, parent_ip, flags, pc);
959 }
960
961 static void __ftrace_trace_stack(struct trace_array *tr,
962 unsigned long flags,
963 int skip, int pc)
964 {
965 #ifdef CONFIG_STACKTRACE
966 struct ring_buffer_event *event;
967 struct stack_entry *entry;
968 struct stack_trace trace;
969
970 event = trace_buffer_lock_reserve(tr, TRACE_STACK,
971 sizeof(*entry), flags, pc);
972 if (!event)
973 return;
974 entry = ring_buffer_event_data(event);
975 memset(&entry->caller, 0, sizeof(entry->caller));
976
977 trace.nr_entries = 0;
978 trace.max_entries = FTRACE_STACK_ENTRIES;
979 trace.skip = skip;
980 trace.entries = entry->caller;
981
982 save_stack_trace(&trace);
983 ring_buffer_unlock_commit(tr->buffer, event);
984 #endif
985 }
986
987 static void ftrace_trace_stack(struct trace_array *tr,
988 unsigned long flags,
989 int skip, int pc)
990 {
991 if (!(trace_flags & TRACE_ITER_STACKTRACE))
992 return;
993
994 __ftrace_trace_stack(tr, flags, skip, pc);
995 }
996
997 void __trace_stack(struct trace_array *tr,
998 unsigned long flags,
999 int skip, int pc)
1000 {
1001 __ftrace_trace_stack(tr, flags, skip, pc);
1002 }
1003
1004 static void ftrace_trace_userstack(struct trace_array *tr,
1005 unsigned long flags, int pc)
1006 {
1007 #ifdef CONFIG_STACKTRACE
1008 struct ring_buffer_event *event;
1009 struct userstack_entry *entry;
1010 struct stack_trace trace;
1011
1012 if (!(trace_flags & TRACE_ITER_USERSTACKTRACE))
1013 return;
1014
1015 event = trace_buffer_lock_reserve(tr, TRACE_USER_STACK,
1016 sizeof(*entry), flags, pc);
1017 if (!event)
1018 return;
1019 entry = ring_buffer_event_data(event);
1020
1021 memset(&entry->caller, 0, sizeof(entry->caller));
1022
1023 trace.nr_entries = 0;
1024 trace.max_entries = FTRACE_STACK_ENTRIES;
1025 trace.skip = 0;
1026 trace.entries = entry->caller;
1027
1028 save_stack_trace_user(&trace);
1029 ring_buffer_unlock_commit(tr->buffer, event);
1030 #endif
1031 }
1032
1033 #ifdef UNUSED
1034 static void __trace_userstack(struct trace_array *tr, unsigned long flags)
1035 {
1036 ftrace_trace_userstack(tr, flags, preempt_count());
1037 }
1038 #endif /* UNUSED */
1039
1040 static void
1041 ftrace_trace_special(void *__tr,
1042 unsigned long arg1, unsigned long arg2, unsigned long arg3,
1043 int pc)
1044 {
1045 struct ring_buffer_event *event;
1046 struct trace_array *tr = __tr;
1047 struct special_entry *entry;
1048
1049 event = trace_buffer_lock_reserve(tr, TRACE_SPECIAL,
1050 sizeof(*entry), 0, pc);
1051 if (!event)
1052 return;
1053 entry = ring_buffer_event_data(event);
1054 entry->arg1 = arg1;
1055 entry->arg2 = arg2;
1056 entry->arg3 = arg3;
1057 trace_buffer_unlock_commit(tr, event, 0, pc);
1058 }
1059
1060 void
1061 __trace_special(void *__tr, void *__data,
1062 unsigned long arg1, unsigned long arg2, unsigned long arg3)
1063 {
1064 ftrace_trace_special(__tr, arg1, arg2, arg3, preempt_count());
1065 }
1066
1067 void
1068 tracing_sched_switch_trace(struct trace_array *tr,
1069 struct task_struct *prev,
1070 struct task_struct *next,
1071 unsigned long flags, int pc)
1072 {
1073 struct ring_buffer_event *event;
1074 struct ctx_switch_entry *entry;
1075
1076 event = trace_buffer_lock_reserve(tr, TRACE_CTX,
1077 sizeof(*entry), flags, pc);
1078 if (!event)
1079 return;
1080 entry = ring_buffer_event_data(event);
1081 entry->prev_pid = prev->pid;
1082 entry->prev_prio = prev->prio;
1083 entry->prev_state = prev->state;
1084 entry->next_pid = next->pid;
1085 entry->next_prio = next->prio;
1086 entry->next_state = next->state;
1087 entry->next_cpu = task_cpu(next);
1088 trace_buffer_unlock_commit(tr, event, flags, pc);
1089 }
1090
1091 void
1092 tracing_sched_wakeup_trace(struct trace_array *tr,
1093 struct task_struct *wakee,
1094 struct task_struct *curr,
1095 unsigned long flags, int pc)
1096 {
1097 struct ring_buffer_event *event;
1098 struct ctx_switch_entry *entry;
1099
1100 event = trace_buffer_lock_reserve(tr, TRACE_WAKE,
1101 sizeof(*entry), flags, pc);
1102 if (!event)
1103 return;
1104 entry = ring_buffer_event_data(event);
1105 entry->prev_pid = curr->pid;
1106 entry->prev_prio = curr->prio;
1107 entry->prev_state = curr->state;
1108 entry->next_pid = wakee->pid;
1109 entry->next_prio = wakee->prio;
1110 entry->next_state = wakee->state;
1111 entry->next_cpu = task_cpu(wakee);
1112
1113 ring_buffer_unlock_commit(tr->buffer, event);
1114 ftrace_trace_stack(tr, flags, 6, pc);
1115 ftrace_trace_userstack(tr, flags, pc);
1116 }
1117
1118 void
1119 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3)
1120 {
1121 struct trace_array *tr = &global_trace;
1122 struct trace_array_cpu *data;
1123 unsigned long flags;
1124 int cpu;
1125 int pc;
1126
1127 if (tracing_disabled)
1128 return;
1129
1130 pc = preempt_count();
1131 local_irq_save(flags);
1132 cpu = raw_smp_processor_id();
1133 data = tr->data[cpu];
1134
1135 if (likely(atomic_inc_return(&data->disabled) == 1))
1136 ftrace_trace_special(tr, arg1, arg2, arg3, pc);
1137
1138 atomic_dec(&data->disabled);
1139 local_irq_restore(flags);
1140 }
1141
1142 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1143 int trace_graph_entry(struct ftrace_graph_ent *trace)
1144 {
1145 struct trace_array *tr = &global_trace;
1146 struct trace_array_cpu *data;
1147 unsigned long flags;
1148 long disabled;
1149 int cpu;
1150 int pc;
1151
1152 if (!ftrace_trace_task(current))
1153 return 0;
1154
1155 if (!ftrace_graph_addr(trace->func))
1156 return 0;
1157
1158 local_irq_save(flags);
1159 cpu = raw_smp_processor_id();
1160 data = tr->data[cpu];
1161 disabled = atomic_inc_return(&data->disabled);
1162 if (likely(disabled == 1)) {
1163 pc = preempt_count();
1164 __trace_graph_entry(tr, trace, flags, pc);
1165 }
1166 /* Only do the atomic if it is not already set */
1167 if (!test_tsk_trace_graph(current))
1168 set_tsk_trace_graph(current);
1169 atomic_dec(&data->disabled);
1170 local_irq_restore(flags);
1171
1172 return 1;
1173 }
1174
1175 void trace_graph_return(struct ftrace_graph_ret *trace)
1176 {
1177 struct trace_array *tr = &global_trace;
1178 struct trace_array_cpu *data;
1179 unsigned long flags;
1180 long disabled;
1181 int cpu;
1182 int pc;
1183
1184 local_irq_save(flags);
1185 cpu = raw_smp_processor_id();
1186 data = tr->data[cpu];
1187 disabled = atomic_inc_return(&data->disabled);
1188 if (likely(disabled == 1)) {
1189 pc = preempt_count();
1190 __trace_graph_return(tr, trace, flags, pc);
1191 }
1192 if (!trace->depth)
1193 clear_tsk_trace_graph(current);
1194 atomic_dec(&data->disabled);
1195 local_irq_restore(flags);
1196 }
1197 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1198
1199
1200 /**
1201 * trace_vbprintk - write binary msg to tracing buffer
1202 *
1203 */
1204 int trace_vbprintk(unsigned long ip, int depth, const char *fmt, va_list args)
1205 {
1206 static raw_spinlock_t trace_buf_lock =
1207 (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
1208 static u32 trace_buf[TRACE_BUF_SIZE];
1209
1210 struct ring_buffer_event *event;
1211 struct trace_array *tr = &global_trace;
1212 struct trace_array_cpu *data;
1213 struct bprint_entry *entry;
1214 unsigned long flags;
1215 int resched;
1216 int cpu, len = 0, size, pc;
1217
1218 if (unlikely(tracing_selftest_running || tracing_disabled))
1219 return 0;
1220
1221 /* Don't pollute graph traces with trace_vprintk internals */
1222 pause_graph_tracing();
1223
1224 pc = preempt_count();
1225 resched = ftrace_preempt_disable();
1226 cpu = raw_smp_processor_id();
1227 data = tr->data[cpu];
1228
1229 if (unlikely(atomic_read(&data->disabled)))
1230 goto out;
1231
1232 /* Lockdep uses trace_printk for lock tracing */
1233 local_irq_save(flags);
1234 __raw_spin_lock(&trace_buf_lock);
1235 len = vbin_printf(trace_buf, TRACE_BUF_SIZE, fmt, args);
1236
1237 if (len > TRACE_BUF_SIZE || len < 0)
1238 goto out_unlock;
1239
1240 size = sizeof(*entry) + sizeof(u32) * len;
1241 event = trace_buffer_lock_reserve(tr, TRACE_BPRINT, size, flags, pc);
1242 if (!event)
1243 goto out_unlock;
1244 entry = ring_buffer_event_data(event);
1245 entry->ip = ip;
1246 entry->depth = depth;
1247 entry->fmt = fmt;
1248
1249 memcpy(entry->buf, trace_buf, sizeof(u32) * len);
1250 ring_buffer_unlock_commit(tr->buffer, event);
1251
1252 out_unlock:
1253 __raw_spin_unlock(&trace_buf_lock);
1254 local_irq_restore(flags);
1255
1256 out:
1257 ftrace_preempt_enable(resched);
1258 unpause_graph_tracing();
1259
1260 return len;
1261 }
1262 EXPORT_SYMBOL_GPL(trace_vbprintk);
1263
1264 int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args)
1265 {
1266 static raw_spinlock_t trace_buf_lock = __RAW_SPIN_LOCK_UNLOCKED;
1267 static char trace_buf[TRACE_BUF_SIZE];
1268
1269 struct ring_buffer_event *event;
1270 struct trace_array *tr = &global_trace;
1271 struct trace_array_cpu *data;
1272 int cpu, len = 0, size, pc;
1273 struct print_entry *entry;
1274 unsigned long irq_flags;
1275
1276 if (tracing_disabled || tracing_selftest_running)
1277 return 0;
1278
1279 pc = preempt_count();
1280 preempt_disable_notrace();
1281 cpu = raw_smp_processor_id();
1282 data = tr->data[cpu];
1283
1284 if (unlikely(atomic_read(&data->disabled)))
1285 goto out;
1286
1287 pause_graph_tracing();
1288 raw_local_irq_save(irq_flags);
1289 __raw_spin_lock(&trace_buf_lock);
1290 len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);
1291
1292 len = min(len, TRACE_BUF_SIZE-1);
1293 trace_buf[len] = 0;
1294
1295 size = sizeof(*entry) + len + 1;
1296 event = trace_buffer_lock_reserve(tr, TRACE_PRINT, size, irq_flags, pc);
1297 if (!event)
1298 goto out_unlock;
1299 entry = ring_buffer_event_data(event);
1300 entry->ip = ip;
1301 entry->depth = depth;
1302
1303 memcpy(&entry->buf, trace_buf, len);
1304 entry->buf[len] = 0;
1305 ring_buffer_unlock_commit(tr->buffer, event);
1306
1307 out_unlock:
1308 __raw_spin_unlock(&trace_buf_lock);
1309 raw_local_irq_restore(irq_flags);
1310 unpause_graph_tracing();
1311 out:
1312 preempt_enable_notrace();
1313
1314 return len;
1315 }
1316 EXPORT_SYMBOL_GPL(trace_vprintk);
1317
1318 enum trace_file_type {
1319 TRACE_FILE_LAT_FMT = 1,
1320 TRACE_FILE_ANNOTATE = 2,
1321 };
1322
1323 static void trace_iterator_increment(struct trace_iterator *iter)
1324 {
1325 /* Don't allow ftrace to trace into the ring buffers */
1326 ftrace_disable_cpu();
1327
1328 iter->idx++;
1329 if (iter->buffer_iter[iter->cpu])
1330 ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
1331
1332 ftrace_enable_cpu();
1333 }
1334
1335 static struct trace_entry *
1336 peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts)
1337 {
1338 struct ring_buffer_event *event;
1339 struct ring_buffer_iter *buf_iter = iter->buffer_iter[cpu];
1340
1341 /* Don't allow ftrace to trace into the ring buffers */
1342 ftrace_disable_cpu();
1343
1344 if (buf_iter)
1345 event = ring_buffer_iter_peek(buf_iter, ts);
1346 else
1347 event = ring_buffer_peek(iter->tr->buffer, cpu, ts);
1348
1349 ftrace_enable_cpu();
1350
1351 return event ? ring_buffer_event_data(event) : NULL;
1352 }
1353
1354 static struct trace_entry *
1355 __find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts)
1356 {
1357 struct ring_buffer *buffer = iter->tr->buffer;
1358 struct trace_entry *ent, *next = NULL;
1359 int cpu_file = iter->cpu_file;
1360 u64 next_ts = 0, ts;
1361 int next_cpu = -1;
1362 int cpu;
1363
1364 /*
1365 * If we are in a per_cpu trace file, don't bother by iterating over
1366 * all cpu and peek directly.
1367 */
1368 if (cpu_file > TRACE_PIPE_ALL_CPU) {
1369 if (ring_buffer_empty_cpu(buffer, cpu_file))
1370 return NULL;
1371 ent = peek_next_entry(iter, cpu_file, ent_ts);
1372 if (ent_cpu)
1373 *ent_cpu = cpu_file;
1374
1375 return ent;
1376 }
1377
1378 for_each_tracing_cpu(cpu) {
1379
1380 if (ring_buffer_empty_cpu(buffer, cpu))
1381 continue;
1382
1383 ent = peek_next_entry(iter, cpu, &ts);
1384
1385 /*
1386 * Pick the entry with the smallest timestamp:
1387 */
1388 if (ent && (!next || ts < next_ts)) {
1389 next = ent;
1390 next_cpu = cpu;
1391 next_ts = ts;
1392 }
1393 }
1394
1395 if (ent_cpu)
1396 *ent_cpu = next_cpu;
1397
1398 if (ent_ts)
1399 *ent_ts = next_ts;
1400
1401 return next;
1402 }
1403
1404 /* Find the next real entry, without updating the iterator itself */
1405 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
1406 int *ent_cpu, u64 *ent_ts)
1407 {
1408 return __find_next_entry(iter, ent_cpu, ent_ts);
1409 }
1410
1411 /* Find the next real entry, and increment the iterator to the next entry */
1412 static void *find_next_entry_inc(struct trace_iterator *iter)
1413 {
1414 iter->ent = __find_next_entry(iter, &iter->cpu, &iter->ts);
1415
1416 if (iter->ent)
1417 trace_iterator_increment(iter);
1418
1419 return iter->ent ? iter : NULL;
1420 }
1421
1422 static void trace_consume(struct trace_iterator *iter)
1423 {
1424 /* Don't allow ftrace to trace into the ring buffers */
1425 ftrace_disable_cpu();
1426 ring_buffer_consume(iter->tr->buffer, iter->cpu, &iter->ts);
1427 ftrace_enable_cpu();
1428 }
1429
1430 static void *s_next(struct seq_file *m, void *v, loff_t *pos)
1431 {
1432 struct trace_iterator *iter = m->private;
1433 int i = (int)*pos;
1434 void *ent;
1435
1436 (*pos)++;
1437
1438 /* can't go backwards */
1439 if (iter->idx > i)
1440 return NULL;
1441
1442 if (iter->idx < 0)
1443 ent = find_next_entry_inc(iter);
1444 else
1445 ent = iter;
1446
1447 while (ent && iter->idx < i)
1448 ent = find_next_entry_inc(iter);
1449
1450 iter->pos = *pos;
1451
1452 return ent;
1453 }
1454
1455 /*
1456 * No necessary locking here. The worst thing which can
1457 * happen is loosing events consumed at the same time
1458 * by a trace_pipe reader.
1459 * Other than that, we don't risk to crash the ring buffer
1460 * because it serializes the readers.
1461 *
1462 * The current tracer is copied to avoid a global locking
1463 * all around.
1464 */
1465 static void *s_start(struct seq_file *m, loff_t *pos)
1466 {
1467 struct trace_iterator *iter = m->private;
1468 static struct tracer *old_tracer;
1469 int cpu_file = iter->cpu_file;
1470 void *p = NULL;
1471 loff_t l = 0;
1472 int cpu;
1473
1474 /* copy the tracer to avoid using a global lock all around */
1475 mutex_lock(&trace_types_lock);
1476 if (unlikely(old_tracer != current_trace && current_trace)) {
1477 old_tracer = current_trace;
1478 *iter->trace = *current_trace;
1479 }
1480 mutex_unlock(&trace_types_lock);
1481
1482 atomic_inc(&trace_record_cmdline_disabled);
1483
1484 if (*pos != iter->pos) {
1485 iter->ent = NULL;
1486 iter->cpu = 0;
1487 iter->idx = -1;
1488
1489 ftrace_disable_cpu();
1490
1491 if (cpu_file == TRACE_PIPE_ALL_CPU) {
1492 for_each_tracing_cpu(cpu)
1493 ring_buffer_iter_reset(iter->buffer_iter[cpu]);
1494 } else
1495 ring_buffer_iter_reset(iter->buffer_iter[cpu_file]);
1496
1497
1498 ftrace_enable_cpu();
1499
1500 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
1501 ;
1502
1503 } else {
1504 l = *pos - 1;
1505 p = s_next(m, p, &l);
1506 }
1507
1508 return p;
1509 }
1510
1511 static void s_stop(struct seq_file *m, void *p)
1512 {
1513 atomic_dec(&trace_record_cmdline_disabled);
1514 }
1515
1516 static void print_lat_help_header(struct seq_file *m)
1517 {
1518 seq_puts(m, "# _------=> CPU# \n");
1519 seq_puts(m, "# / _-----=> irqs-off \n");
1520 seq_puts(m, "# | / _----=> need-resched \n");
1521 seq_puts(m, "# || / _---=> hardirq/softirq \n");
1522 seq_puts(m, "# ||| / _--=> preempt-depth \n");
1523 seq_puts(m, "# |||| / \n");
1524 seq_puts(m, "# ||||| delay \n");
1525 seq_puts(m, "# cmd pid ||||| time | caller \n");
1526 seq_puts(m, "# \\ / ||||| \\ | / \n");
1527 }
1528
1529 static void print_func_help_header(struct seq_file *m)
1530 {
1531 seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1532 seq_puts(m, "# | | | | |\n");
1533 }
1534
1535
1536 static void
1537 print_trace_header(struct seq_file *m, struct trace_iterator *iter)
1538 {
1539 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1540 struct trace_array *tr = iter->tr;
1541 struct trace_array_cpu *data = tr->data[tr->cpu];
1542 struct tracer *type = current_trace;
1543 unsigned long total;
1544 unsigned long entries;
1545 const char *name = "preemption";
1546
1547 if (type)
1548 name = type->name;
1549
1550 entries = ring_buffer_entries(iter->tr->buffer);
1551 total = entries +
1552 ring_buffer_overruns(iter->tr->buffer);
1553
1554 seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
1555 name, UTS_RELEASE);
1556 seq_puts(m, "# -----------------------------------"
1557 "---------------------------------\n");
1558 seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
1559 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1560 nsecs_to_usecs(data->saved_latency),
1561 entries,
1562 total,
1563 tr->cpu,
1564 #if defined(CONFIG_PREEMPT_NONE)
1565 "server",
1566 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1567 "desktop",
1568 #elif defined(CONFIG_PREEMPT)
1569 "preempt",
1570 #else
1571 "unknown",
1572 #endif
1573 /* These are reserved for later use */
1574 0, 0, 0, 0);
1575 #ifdef CONFIG_SMP
1576 seq_printf(m, " #P:%d)\n", num_online_cpus());
1577 #else
1578 seq_puts(m, ")\n");
1579 #endif
1580 seq_puts(m, "# -----------------\n");
1581 seq_printf(m, "# | task: %.16s-%d "
1582 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1583 data->comm, data->pid, data->uid, data->nice,
1584 data->policy, data->rt_priority);
1585 seq_puts(m, "# -----------------\n");
1586
1587 if (data->critical_start) {
1588 seq_puts(m, "# => started at: ");
1589 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
1590 trace_print_seq(m, &iter->seq);
1591 seq_puts(m, "\n# => ended at: ");
1592 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
1593 trace_print_seq(m, &iter->seq);
1594 seq_puts(m, "#\n");
1595 }
1596
1597 seq_puts(m, "#\n");
1598 }
1599
1600 static void test_cpu_buff_start(struct trace_iterator *iter)
1601 {
1602 struct trace_seq *s = &iter->seq;
1603
1604 if (!(trace_flags & TRACE_ITER_ANNOTATE))
1605 return;
1606
1607 if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
1608 return;
1609
1610 if (cpumask_test_cpu(iter->cpu, iter->started))
1611 return;
1612
1613 cpumask_set_cpu(iter->cpu, iter->started);
1614 trace_seq_printf(s, "##### CPU %u buffer started ####\n", iter->cpu);
1615 }
1616
1617 static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
1618 {
1619 struct trace_seq *s = &iter->seq;
1620 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1621 struct trace_entry *entry;
1622 struct trace_event *event;
1623
1624 entry = iter->ent;
1625
1626 test_cpu_buff_start(iter);
1627
1628 event = ftrace_find_event(entry->type);
1629
1630 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1631 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
1632 if (!trace_print_lat_context(iter))
1633 goto partial;
1634 } else {
1635 if (!trace_print_context(iter))
1636 goto partial;
1637 }
1638 }
1639
1640 if (event)
1641 return event->trace(iter, sym_flags);
1642
1643 if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
1644 goto partial;
1645
1646 return TRACE_TYPE_HANDLED;
1647 partial:
1648 return TRACE_TYPE_PARTIAL_LINE;
1649 }
1650
1651 static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
1652 {
1653 struct trace_seq *s = &iter->seq;
1654 struct trace_entry *entry;
1655 struct trace_event *event;
1656
1657 entry = iter->ent;
1658
1659 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1660 if (!trace_seq_printf(s, "%d %d %llu ",
1661 entry->pid, iter->cpu, iter->ts))
1662 goto partial;
1663 }
1664
1665 event = ftrace_find_event(entry->type);
1666 if (event)
1667 return event->raw(iter, 0);
1668
1669 if (!trace_seq_printf(s, "%d ?\n", entry->type))
1670 goto partial;
1671
1672 return TRACE_TYPE_HANDLED;
1673 partial:
1674 return TRACE_TYPE_PARTIAL_LINE;
1675 }
1676
1677 static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
1678 {
1679 struct trace_seq *s = &iter->seq;
1680 unsigned char newline = '\n';
1681 struct trace_entry *entry;
1682 struct trace_event *event;
1683
1684 entry = iter->ent;
1685
1686 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1687 SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
1688 SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
1689 SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
1690 }
1691
1692 event = ftrace_find_event(entry->type);
1693 if (event) {
1694 enum print_line_t ret = event->hex(iter, 0);
1695 if (ret != TRACE_TYPE_HANDLED)
1696 return ret;
1697 }
1698
1699 SEQ_PUT_FIELD_RET(s, newline);
1700
1701 return TRACE_TYPE_HANDLED;
1702 }
1703
1704 static enum print_line_t print_bprintk_msg_only(struct trace_iterator *iter)
1705 {
1706 struct trace_seq *s = &iter->seq;
1707 struct trace_entry *entry = iter->ent;
1708 struct bprint_entry *field;
1709 int ret;
1710
1711 trace_assign_type(field, entry);
1712
1713 ret = trace_seq_bprintf(s, field->fmt, field->buf);
1714 if (!ret)
1715 return TRACE_TYPE_PARTIAL_LINE;
1716
1717 return TRACE_TYPE_HANDLED;
1718 }
1719
1720 static enum print_line_t print_printk_msg_only(struct trace_iterator *iter)
1721 {
1722 struct trace_seq *s = &iter->seq;
1723 struct trace_entry *entry = iter->ent;
1724 struct print_entry *field;
1725 int ret;
1726
1727 trace_assign_type(field, entry);
1728
1729 ret = trace_seq_printf(s, "%s", field->buf);
1730 if (!ret)
1731 return TRACE_TYPE_PARTIAL_LINE;
1732
1733 return TRACE_TYPE_HANDLED;
1734 }
1735
1736 static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
1737 {
1738 struct trace_seq *s = &iter->seq;
1739 struct trace_entry *entry;
1740 struct trace_event *event;
1741
1742 entry = iter->ent;
1743
1744 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1745 SEQ_PUT_FIELD_RET(s, entry->pid);
1746 SEQ_PUT_FIELD_RET(s, iter->cpu);
1747 SEQ_PUT_FIELD_RET(s, iter->ts);
1748 }
1749
1750 event = ftrace_find_event(entry->type);
1751 return event ? event->binary(iter, 0) : TRACE_TYPE_HANDLED;
1752 }
1753
1754 static int trace_empty(struct trace_iterator *iter)
1755 {
1756 int cpu;
1757
1758 /* If we are looking at one CPU buffer, only check that one */
1759 if (iter->cpu_file != TRACE_PIPE_ALL_CPU) {
1760 cpu = iter->cpu_file;
1761 if (iter->buffer_iter[cpu]) {
1762 if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
1763 return 0;
1764 } else {
1765 if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
1766 return 0;
1767 }
1768 return 1;
1769 }
1770
1771 for_each_tracing_cpu(cpu) {
1772 if (iter->buffer_iter[cpu]) {
1773 if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
1774 return 0;
1775 } else {
1776 if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
1777 return 0;
1778 }
1779 }
1780
1781 return 1;
1782 }
1783
1784 static enum print_line_t print_trace_line(struct trace_iterator *iter)
1785 {
1786 enum print_line_t ret;
1787
1788 if (iter->trace && iter->trace->print_line) {
1789 ret = iter->trace->print_line(iter);
1790 if (ret != TRACE_TYPE_UNHANDLED)
1791 return ret;
1792 }
1793
1794 if (iter->ent->type == TRACE_BPRINT &&
1795 trace_flags & TRACE_ITER_PRINTK &&
1796 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
1797 return print_bprintk_msg_only(iter);
1798
1799 if (iter->ent->type == TRACE_PRINT &&
1800 trace_flags & TRACE_ITER_PRINTK &&
1801 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
1802 return print_printk_msg_only(iter);
1803
1804 if (trace_flags & TRACE_ITER_BIN)
1805 return print_bin_fmt(iter);
1806
1807 if (trace_flags & TRACE_ITER_HEX)
1808 return print_hex_fmt(iter);
1809
1810 if (trace_flags & TRACE_ITER_RAW)
1811 return print_raw_fmt(iter);
1812
1813 return print_trace_fmt(iter);
1814 }
1815
1816 static int s_show(struct seq_file *m, void *v)
1817 {
1818 struct trace_iterator *iter = v;
1819
1820 if (iter->ent == NULL) {
1821 if (iter->tr) {
1822 seq_printf(m, "# tracer: %s\n", iter->trace->name);
1823 seq_puts(m, "#\n");
1824 }
1825 if (iter->trace && iter->trace->print_header)
1826 iter->trace->print_header(m);
1827 else if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
1828 /* print nothing if the buffers are empty */
1829 if (trace_empty(iter))
1830 return 0;
1831 print_trace_header(m, iter);
1832 if (!(trace_flags & TRACE_ITER_VERBOSE))
1833 print_lat_help_header(m);
1834 } else {
1835 if (!(trace_flags & TRACE_ITER_VERBOSE))
1836 print_func_help_header(m);
1837 }
1838 } else {
1839 print_trace_line(iter);
1840 trace_print_seq(m, &iter->seq);
1841 }
1842
1843 return 0;
1844 }
1845
1846 static struct seq_operations tracer_seq_ops = {
1847 .start = s_start,
1848 .next = s_next,
1849 .stop = s_stop,
1850 .show = s_show,
1851 };
1852
1853 static struct trace_iterator *
1854 __tracing_open(struct inode *inode, struct file *file)
1855 {
1856 long cpu_file = (long) inode->i_private;
1857 void *fail_ret = ERR_PTR(-ENOMEM);
1858 struct trace_iterator *iter;
1859 struct seq_file *m;
1860 int cpu, ret;
1861
1862 if (tracing_disabled)
1863 return ERR_PTR(-ENODEV);
1864
1865 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1866 if (!iter)
1867 return ERR_PTR(-ENOMEM);
1868
1869 /*
1870 * We make a copy of the current tracer to avoid concurrent
1871 * changes on it while we are reading.
1872 */
1873 mutex_lock(&trace_types_lock);
1874 iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
1875 if (!iter->trace)
1876 goto fail;
1877
1878 if (current_trace)
1879 *iter->trace = *current_trace;
1880
1881 if (current_trace && current_trace->print_max)
1882 iter->tr = &max_tr;
1883 else
1884 iter->tr = &global_trace;
1885 iter->pos = -1;
1886 mutex_init(&iter->mutex);
1887 iter->cpu_file = cpu_file;
1888
1889 /* Notify the tracer early; before we stop tracing. */
1890 if (iter->trace && iter->trace->open)
1891 iter->trace->open(iter);
1892
1893 /* Annotate start of buffers if we had overruns */
1894 if (ring_buffer_overruns(iter->tr->buffer))
1895 iter->iter_flags |= TRACE_FILE_ANNOTATE;
1896
1897 if (iter->cpu_file == TRACE_PIPE_ALL_CPU) {
1898 for_each_tracing_cpu(cpu) {
1899
1900 iter->buffer_iter[cpu] =
1901 ring_buffer_read_start(iter->tr->buffer, cpu);
1902 }
1903 } else {
1904 cpu = iter->cpu_file;
1905 iter->buffer_iter[cpu] =
1906 ring_buffer_read_start(iter->tr->buffer, cpu);
1907 }
1908
1909 /* TODO stop tracer */
1910 ret = seq_open(file, &tracer_seq_ops);
1911 if (ret < 0) {
1912 fail_ret = ERR_PTR(ret);
1913 goto fail_buffer;
1914 }
1915
1916 m = file->private_data;
1917 m->private = iter;
1918
1919 /* stop the trace while dumping */
1920 tracing_stop();
1921
1922 mutex_unlock(&trace_types_lock);
1923
1924 return iter;
1925
1926 fail_buffer:
1927 for_each_tracing_cpu(cpu) {
1928 if (iter->buffer_iter[cpu])
1929 ring_buffer_read_finish(iter->buffer_iter[cpu]);
1930 }
1931 fail:
1932 mutex_unlock(&trace_types_lock);
1933 kfree(iter->trace);
1934 kfree(iter);
1935
1936 return fail_ret;
1937 }
1938
1939 int tracing_open_generic(struct inode *inode, struct file *filp)
1940 {
1941 if (tracing_disabled)
1942 return -ENODEV;
1943
1944 filp->private_data = inode->i_private;
1945 return 0;
1946 }
1947
1948 static int tracing_release(struct inode *inode, struct file *file)
1949 {
1950 struct seq_file *m = (struct seq_file *)file->private_data;
1951 struct trace_iterator *iter = m->private;
1952 int cpu;
1953
1954 mutex_lock(&trace_types_lock);
1955 for_each_tracing_cpu(cpu) {
1956 if (iter->buffer_iter[cpu])
1957 ring_buffer_read_finish(iter->buffer_iter[cpu]);
1958 }
1959
1960 if (iter->trace && iter->trace->close)
1961 iter->trace->close(iter);
1962
1963 /* reenable tracing if it was previously enabled */
1964 tracing_start();
1965 mutex_unlock(&trace_types_lock);
1966
1967 seq_release(inode, file);
1968 mutex_destroy(&iter->mutex);
1969 kfree(iter->trace);
1970 kfree(iter);
1971 return 0;
1972 }
1973
1974 static int tracing_open(struct inode *inode, struct file *file)
1975 {
1976 struct trace_iterator *iter;
1977 int ret = 0;
1978
1979 iter = __tracing_open(inode, file);
1980 if (IS_ERR(iter))
1981 ret = PTR_ERR(iter);
1982 else if (trace_flags & TRACE_ITER_LATENCY_FMT)
1983 iter->iter_flags |= TRACE_FILE_LAT_FMT;
1984
1985 return ret;
1986 }
1987
1988 static void *
1989 t_next(struct seq_file *m, void *v, loff_t *pos)
1990 {
1991 struct tracer *t = m->private;
1992
1993 (*pos)++;
1994
1995 if (t)
1996 t = t->next;
1997
1998 m->private = t;
1999
2000 return t;
2001 }
2002
2003 static void *t_start(struct seq_file *m, loff_t *pos)
2004 {
2005 struct tracer *t = m->private;
2006 loff_t l = 0;
2007
2008 mutex_lock(&trace_types_lock);
2009 for (; t && l < *pos; t = t_next(m, t, &l))
2010 ;
2011
2012 return t;
2013 }
2014
2015 static void t_stop(struct seq_file *m, void *p)
2016 {
2017 mutex_unlock(&trace_types_lock);
2018 }
2019
2020 static int t_show(struct seq_file *m, void *v)
2021 {
2022 struct tracer *t = v;
2023
2024 if (!t)
2025 return 0;
2026
2027 seq_printf(m, "%s", t->name);
2028 if (t->next)
2029 seq_putc(m, ' ');
2030 else
2031 seq_putc(m, '\n');
2032
2033 return 0;
2034 }
2035
2036 static struct seq_operations show_traces_seq_ops = {
2037 .start = t_start,
2038 .next = t_next,
2039 .stop = t_stop,
2040 .show = t_show,
2041 };
2042
2043 static int show_traces_open(struct inode *inode, struct file *file)
2044 {
2045 int ret;
2046
2047 if (tracing_disabled)
2048 return -ENODEV;
2049
2050 ret = seq_open(file, &show_traces_seq_ops);
2051 if (!ret) {
2052 struct seq_file *m = file->private_data;
2053 m->private = trace_types;
2054 }
2055
2056 return ret;
2057 }
2058
2059 static const struct file_operations tracing_fops = {
2060 .open = tracing_open,
2061 .read = seq_read,
2062 .llseek = seq_lseek,
2063 .release = tracing_release,
2064 };
2065
2066 static const struct file_operations show_traces_fops = {
2067 .open = show_traces_open,
2068 .read = seq_read,
2069 .release = seq_release,
2070 };
2071
2072 /*
2073 * Only trace on a CPU if the bitmask is set:
2074 */
2075 static cpumask_var_t tracing_cpumask;
2076
2077 /*
2078 * The tracer itself will not take this lock, but still we want
2079 * to provide a consistent cpumask to user-space:
2080 */
2081 static DEFINE_MUTEX(tracing_cpumask_update_lock);
2082
2083 /*
2084 * Temporary storage for the character representation of the
2085 * CPU bitmask (and one more byte for the newline):
2086 */
2087 static char mask_str[NR_CPUS + 1];
2088
2089 static ssize_t
2090 tracing_cpumask_read(struct file *filp, char __user *ubuf,
2091 size_t count, loff_t *ppos)
2092 {
2093 int len;
2094
2095 mutex_lock(&tracing_cpumask_update_lock);
2096
2097 len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
2098 if (count - len < 2) {
2099 count = -EINVAL;
2100 goto out_err;
2101 }
2102 len += sprintf(mask_str + len, "\n");
2103 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
2104
2105 out_err:
2106 mutex_unlock(&tracing_cpumask_update_lock);
2107
2108 return count;
2109 }
2110
2111 static ssize_t
2112 tracing_cpumask_write(struct file *filp, const char __user *ubuf,
2113 size_t count, loff_t *ppos)
2114 {
2115 int err, cpu;
2116 cpumask_var_t tracing_cpumask_new;
2117
2118 if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
2119 return -ENOMEM;
2120
2121 mutex_lock(&tracing_cpumask_update_lock);
2122 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
2123 if (err)
2124 goto err_unlock;
2125
2126 local_irq_disable();
2127 __raw_spin_lock(&ftrace_max_lock);
2128 for_each_tracing_cpu(cpu) {
2129 /*
2130 * Increase/decrease the disabled counter if we are
2131 * about to flip a bit in the cpumask:
2132 */
2133 if (cpumask_test_cpu(cpu, tracing_cpumask) &&
2134 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
2135 atomic_inc(&global_trace.data[cpu]->disabled);
2136 }
2137 if (!cpumask_test_cpu(cpu, tracing_cpumask) &&
2138 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
2139 atomic_dec(&global_trace.data[cpu]->disabled);
2140 }
2141 }
2142 __raw_spin_unlock(&ftrace_max_lock);
2143 local_irq_enable();
2144
2145 cpumask_copy(tracing_cpumask, tracing_cpumask_new);
2146
2147 mutex_unlock(&tracing_cpumask_update_lock);
2148 free_cpumask_var(tracing_cpumask_new);
2149
2150 return count;
2151
2152 err_unlock:
2153 mutex_unlock(&tracing_cpumask_update_lock);
2154 free_cpumask_var(tracing_cpumask);
2155
2156 return err;
2157 }
2158
2159 static const struct file_operations tracing_cpumask_fops = {
2160 .open = tracing_open_generic,
2161 .read = tracing_cpumask_read,
2162 .write = tracing_cpumask_write,
2163 };
2164
2165 static ssize_t
2166 tracing_trace_options_read(struct file *filp, char __user *ubuf,
2167 size_t cnt, loff_t *ppos)
2168 {
2169 struct tracer_opt *trace_opts;
2170 u32 tracer_flags;
2171 int len = 0;
2172 char *buf;
2173 int r = 0;
2174 int i;
2175
2176
2177 /* calculate max size */
2178 for (i = 0; trace_options[i]; i++) {
2179 len += strlen(trace_options[i]);
2180 len += 3; /* "no" and newline */
2181 }
2182
2183 mutex_lock(&trace_types_lock);
2184 tracer_flags = current_trace->flags->val;
2185 trace_opts = current_trace->flags->opts;
2186
2187 /*
2188 * Increase the size with names of options specific
2189 * of the current tracer.
2190 */
2191 for (i = 0; trace_opts[i].name; i++) {
2192 len += strlen(trace_opts[i].name);
2193 len += 3; /* "no" and newline */
2194 }
2195
2196 /* +2 for \n and \0 */
2197 buf = kmalloc(len + 2, GFP_KERNEL);
2198 if (!buf) {
2199 mutex_unlock(&trace_types_lock);
2200 return -ENOMEM;
2201 }
2202
2203 for (i = 0; trace_options[i]; i++) {
2204 if (trace_flags & (1 << i))
2205 r += sprintf(buf + r, "%s\n", trace_options[i]);
2206 else
2207 r += sprintf(buf + r, "no%s\n", trace_options[i]);
2208 }
2209
2210 for (i = 0; trace_opts[i].name; i++) {
2211 if (tracer_flags & trace_opts[i].bit)
2212 r += sprintf(buf + r, "%s\n",
2213 trace_opts[i].name);
2214 else
2215 r += sprintf(buf + r, "no%s\n",
2216 trace_opts[i].name);
2217 }
2218 mutex_unlock(&trace_types_lock);
2219
2220 WARN_ON(r >= len + 2);
2221
2222 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2223
2224 kfree(buf);
2225 return r;
2226 }
2227
2228 /* Try to assign a tracer specific option */
2229 static int set_tracer_option(struct tracer *trace, char *cmp, int neg)
2230 {
2231 struct tracer_flags *trace_flags = trace->flags;
2232 struct tracer_opt *opts = NULL;
2233 int ret = 0, i = 0;
2234 int len;
2235
2236 for (i = 0; trace_flags->opts[i].name; i++) {
2237 opts = &trace_flags->opts[i];
2238 len = strlen(opts->name);
2239
2240 if (strncmp(cmp, opts->name, len) == 0) {
2241 ret = trace->set_flag(trace_flags->val,
2242 opts->bit, !neg);
2243 break;
2244 }
2245 }
2246 /* Not found */
2247 if (!trace_flags->opts[i].name)
2248 return -EINVAL;
2249
2250 /* Refused to handle */
2251 if (ret)
2252 return ret;
2253
2254 if (neg)
2255 trace_flags->val &= ~opts->bit;
2256 else
2257 trace_flags->val |= opts->bit;
2258
2259 return 0;
2260 }
2261
2262 static void set_tracer_flags(unsigned int mask, int enabled)
2263 {
2264 /* do nothing if flag is already set */
2265 if (!!(trace_flags & mask) == !!enabled)
2266 return;
2267
2268 if (enabled)
2269 trace_flags |= mask;
2270 else
2271 trace_flags &= ~mask;
2272
2273 if (mask == TRACE_ITER_GLOBAL_CLK) {
2274 u64 (*func)(void);
2275
2276 if (enabled)
2277 func = trace_clock_global;
2278 else
2279 func = trace_clock_local;
2280
2281 mutex_lock(&trace_types_lock);
2282 ring_buffer_set_clock(global_trace.buffer, func);
2283
2284 if (max_tr.buffer)
2285 ring_buffer_set_clock(max_tr.buffer, func);
2286 mutex_unlock(&trace_types_lock);
2287 }
2288 }
2289
2290 static ssize_t
2291 tracing_trace_options_write(struct file *filp, const char __user *ubuf,
2292 size_t cnt, loff_t *ppos)
2293 {
2294 char buf[64];
2295 char *cmp = buf;
2296 int neg = 0;
2297 int ret;
2298 int i;
2299
2300 if (cnt >= sizeof(buf))
2301 return -EINVAL;
2302
2303 if (copy_from_user(&buf, ubuf, cnt))
2304 return -EFAULT;
2305
2306 buf[cnt] = 0;
2307
2308 if (strncmp(buf, "no", 2) == 0) {
2309 neg = 1;
2310 cmp += 2;
2311 }
2312
2313 for (i = 0; trace_options[i]; i++) {
2314 int len = strlen(trace_options[i]);
2315
2316 if (strncmp(cmp, trace_options[i], len) == 0) {
2317 set_tracer_flags(1 << i, !neg);
2318 break;
2319 }
2320 }
2321
2322 /* If no option could be set, test the specific tracer options */
2323 if (!trace_options[i]) {
2324 mutex_lock(&trace_types_lock);
2325 ret = set_tracer_option(current_trace, cmp, neg);
2326 mutex_unlock(&trace_types_lock);
2327 if (ret)
2328 return ret;
2329 }
2330
2331 filp->f_pos += cnt;
2332
2333 return cnt;
2334 }
2335
2336 static const struct file_operations tracing_iter_fops = {
2337 .open = tracing_open_generic,
2338 .read = tracing_trace_options_read,
2339 .write = tracing_trace_options_write,
2340 };
2341
2342 static const char readme_msg[] =
2343 "tracing mini-HOWTO:\n\n"
2344 "# mkdir /debug\n"
2345 "# mount -t debugfs nodev /debug\n\n"
2346 "# cat /debug/tracing/available_tracers\n"
2347 "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
2348 "# cat /debug/tracing/current_tracer\n"
2349 "none\n"
2350 "# echo sched_switch > /debug/tracing/current_tracer\n"
2351 "# cat /debug/tracing/current_tracer\n"
2352 "sched_switch\n"
2353 "# cat /debug/tracing/trace_options\n"
2354 "noprint-parent nosym-offset nosym-addr noverbose\n"
2355 "# echo print-parent > /debug/tracing/trace_options\n"
2356 "# echo 1 > /debug/tracing/tracing_enabled\n"
2357 "# cat /debug/tracing/trace > /tmp/trace.txt\n"
2358 "echo 0 > /debug/tracing/tracing_enabled\n"
2359 ;
2360
2361 static ssize_t
2362 tracing_readme_read(struct file *filp, char __user *ubuf,
2363 size_t cnt, loff_t *ppos)
2364 {
2365 return simple_read_from_buffer(ubuf, cnt, ppos,
2366 readme_msg, strlen(readme_msg));
2367 }
2368
2369 static const struct file_operations tracing_readme_fops = {
2370 .open = tracing_open_generic,
2371 .read = tracing_readme_read,
2372 };
2373
2374 static ssize_t
2375 tracing_ctrl_read(struct file *filp, char __user *ubuf,
2376 size_t cnt, loff_t *ppos)
2377 {
2378 char buf[64];
2379 int r;
2380
2381 r = sprintf(buf, "%u\n", tracer_enabled);
2382 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2383 }
2384
2385 static ssize_t
2386 tracing_ctrl_write(struct file *filp, const char __user *ubuf,
2387 size_t cnt, loff_t *ppos)
2388 {
2389 struct trace_array *tr = filp->private_data;
2390 char buf[64];
2391 unsigned long val;
2392 int ret;
2393
2394 if (cnt >= sizeof(buf))
2395 return -EINVAL;
2396
2397 if (copy_from_user(&buf, ubuf, cnt))
2398 return -EFAULT;
2399
2400 buf[cnt] = 0;
2401
2402 ret = strict_strtoul(buf, 10, &val);
2403 if (ret < 0)
2404 return ret;
2405
2406 val = !!val;
2407
2408 mutex_lock(&trace_types_lock);
2409 if (tracer_enabled ^ val) {
2410 if (val) {
2411 tracer_enabled = 1;
2412 if (current_trace->start)
2413 current_trace->start(tr);
2414 tracing_start();
2415 } else {
2416 tracer_enabled = 0;
2417 tracing_stop();
2418 if (current_trace->stop)
2419 current_trace->stop(tr);
2420 }
2421 }
2422 mutex_unlock(&trace_types_lock);
2423
2424 filp->f_pos += cnt;
2425
2426 return cnt;
2427 }
2428
2429 static ssize_t
2430 tracing_set_trace_read(struct file *filp, char __user *ubuf,
2431 size_t cnt, loff_t *ppos)
2432 {
2433 char buf[max_tracer_type_len+2];
2434 int r;
2435
2436 mutex_lock(&trace_types_lock);
2437 if (current_trace)
2438 r = sprintf(buf, "%s\n", current_trace->name);
2439 else
2440 r = sprintf(buf, "\n");
2441 mutex_unlock(&trace_types_lock);
2442
2443 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2444 }
2445
2446 int tracer_init(struct tracer *t, struct trace_array *tr)
2447 {
2448 tracing_reset_online_cpus(tr);
2449 return t->init(tr);
2450 }
2451
2452 static int tracing_resize_ring_buffer(unsigned long size)
2453 {
2454 int ret;
2455
2456 /*
2457 * If kernel or user changes the size of the ring buffer
2458 * we use the size that was given, and we can forget about
2459 * expanding it later.
2460 */
2461 ring_buffer_expanded = 1;
2462
2463 ret = ring_buffer_resize(global_trace.buffer, size);
2464 if (ret < 0)
2465 return ret;
2466
2467 ret = ring_buffer_resize(max_tr.buffer, size);
2468 if (ret < 0) {
2469 int r;
2470
2471 r = ring_buffer_resize(global_trace.buffer,
2472 global_trace.entries);
2473 if (r < 0) {
2474 /*
2475 * AARGH! We are left with different
2476 * size max buffer!!!!
2477 * The max buffer is our "snapshot" buffer.
2478 * When a tracer needs a snapshot (one of the
2479 * latency tracers), it swaps the max buffer
2480 * with the saved snap shot. We succeeded to
2481 * update the size of the main buffer, but failed to
2482 * update the size of the max buffer. But when we tried
2483 * to reset the main buffer to the original size, we
2484 * failed there too. This is very unlikely to
2485 * happen, but if it does, warn and kill all
2486 * tracing.
2487 */
2488 WARN_ON(1);
2489 tracing_disabled = 1;
2490 }
2491 return ret;
2492 }
2493
2494 global_trace.entries = size;
2495
2496 return ret;
2497 }
2498
2499 /**
2500 * tracing_update_buffers - used by tracing facility to expand ring buffers
2501 *
2502 * To save on memory when the tracing is never used on a system with it
2503 * configured in. The ring buffers are set to a minimum size. But once
2504 * a user starts to use the tracing facility, then they need to grow
2505 * to their default size.
2506 *
2507 * This function is to be called when a tracer is about to be used.
2508 */
2509 int tracing_update_buffers(void)
2510 {
2511 int ret = 0;
2512
2513 mutex_lock(&trace_types_lock);
2514 if (!ring_buffer_expanded)
2515 ret = tracing_resize_ring_buffer(trace_buf_size);
2516 mutex_unlock(&trace_types_lock);
2517
2518 return ret;
2519 }
2520
2521 struct trace_option_dentry;
2522
2523 static struct trace_option_dentry *
2524 create_trace_option_files(struct tracer *tracer);
2525
2526 static void
2527 destroy_trace_option_files(struct trace_option_dentry *topts);
2528
2529 static int tracing_set_tracer(const char *buf)
2530 {
2531 static struct trace_option_dentry *topts;
2532 struct trace_array *tr = &global_trace;
2533 struct tracer *t;
2534 int ret = 0;
2535
2536 mutex_lock(&trace_types_lock);
2537
2538 if (!ring_buffer_expanded) {
2539 ret = tracing_resize_ring_buffer(trace_buf_size);
2540 if (ret < 0)
2541 goto out;
2542 ret = 0;
2543 }
2544
2545 for (t = trace_types; t; t = t->next) {
2546 if (strcmp(t->name, buf) == 0)
2547 break;
2548 }
2549 if (!t) {
2550 ret = -EINVAL;
2551 goto out;
2552 }
2553 if (t == current_trace)
2554 goto out;
2555
2556 trace_branch_disable();
2557 if (current_trace && current_trace->reset)
2558 current_trace->reset(tr);
2559
2560 destroy_trace_option_files(topts);
2561
2562 current_trace = t;
2563
2564 topts = create_trace_option_files(current_trace);
2565
2566 if (t->init) {
2567 ret = tracer_init(t, tr);
2568 if (ret)
2569 goto out;
2570 }
2571
2572 trace_branch_enable(tr);
2573 out:
2574 mutex_unlock(&trace_types_lock);
2575
2576 return ret;
2577 }
2578
2579 static ssize_t
2580 tracing_set_trace_write(struct file *filp, const char __user *ubuf,
2581 size_t cnt, loff_t *ppos)
2582 {
2583 char buf[max_tracer_type_len+1];
2584 int i;
2585 size_t ret;
2586 int err;
2587
2588 ret = cnt;
2589
2590 if (cnt > max_tracer_type_len)
2591 cnt = max_tracer_type_len;
2592
2593 if (copy_from_user(&buf, ubuf, cnt))
2594 return -EFAULT;
2595
2596 buf[cnt] = 0;
2597
2598 /* strip ending whitespace. */
2599 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
2600 buf[i] = 0;
2601
2602 err = tracing_set_tracer(buf);
2603 if (err)
2604 return err;
2605
2606 filp->f_pos += ret;
2607
2608 return ret;
2609 }
2610
2611 static ssize_t
2612 tracing_max_lat_read(struct file *filp, char __user *ubuf,
2613 size_t cnt, loff_t *ppos)
2614 {
2615 unsigned long *ptr = filp->private_data;
2616 char buf[64];
2617 int r;
2618
2619 r = snprintf(buf, sizeof(buf), "%ld\n",
2620 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
2621 if (r > sizeof(buf))
2622 r = sizeof(buf);
2623 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2624 }
2625
2626 static ssize_t
2627 tracing_max_lat_write(struct file *filp, const char __user *ubuf,
2628 size_t cnt, loff_t *ppos)
2629 {
2630 unsigned long *ptr = filp->private_data;
2631 char buf[64];
2632 unsigned long val;
2633 int ret;
2634
2635 if (cnt >= sizeof(buf))
2636 return -EINVAL;
2637
2638 if (copy_from_user(&buf, ubuf, cnt))
2639 return -EFAULT;
2640
2641 buf[cnt] = 0;
2642
2643 ret = strict_strtoul(buf, 10, &val);
2644 if (ret < 0)
2645 return ret;
2646
2647 *ptr = val * 1000;
2648
2649 return cnt;
2650 }
2651
2652 static int tracing_open_pipe(struct inode *inode, struct file *filp)
2653 {
2654 long cpu_file = (long) inode->i_private;
2655 struct trace_iterator *iter;
2656 int ret = 0;
2657
2658 if (tracing_disabled)
2659 return -ENODEV;
2660
2661 mutex_lock(&trace_types_lock);
2662
2663 /* We only allow one reader per cpu */
2664 if (cpu_file == TRACE_PIPE_ALL_CPU) {
2665 if (!cpumask_empty(tracing_reader_cpumask)) {
2666 ret = -EBUSY;
2667 goto out;
2668 }
2669 cpumask_setall(tracing_reader_cpumask);
2670 } else {
2671 if (!cpumask_test_cpu(cpu_file, tracing_reader_cpumask))
2672 cpumask_set_cpu(cpu_file, tracing_reader_cpumask);
2673 else {
2674 ret = -EBUSY;
2675 goto out;
2676 }
2677 }
2678
2679 /* create a buffer to store the information to pass to userspace */
2680 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2681 if (!iter) {
2682 ret = -ENOMEM;
2683 goto out;
2684 }
2685
2686 /*
2687 * We make a copy of the current tracer to avoid concurrent
2688 * changes on it while we are reading.
2689 */
2690 iter->trace = kmalloc(sizeof(*iter->trace), GFP_KERNEL);
2691 if (!iter->trace) {
2692 ret = -ENOMEM;
2693 goto fail;
2694 }
2695 if (current_trace)
2696 *iter->trace = *current_trace;
2697
2698 if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
2699 ret = -ENOMEM;
2700 goto fail;
2701 }
2702
2703 /* trace pipe does not show start of buffer */
2704 cpumask_setall(iter->started);
2705
2706 iter->cpu_file = cpu_file;
2707 iter->tr = &global_trace;
2708 mutex_init(&iter->mutex);
2709 filp->private_data = iter;
2710
2711 if (iter->trace->pipe_open)
2712 iter->trace->pipe_open(iter);
2713
2714 out:
2715 mutex_unlock(&trace_types_lock);
2716 return ret;
2717
2718 fail:
2719 kfree(iter->trace);
2720 kfree(iter);
2721 mutex_unlock(&trace_types_lock);
2722 return ret;
2723 }
2724
2725 static int tracing_release_pipe(struct inode *inode, struct file *file)
2726 {
2727 struct trace_iterator *iter = file->private_data;
2728
2729 mutex_lock(&trace_types_lock);
2730
2731 if (iter->cpu_file == TRACE_PIPE_ALL_CPU)
2732 cpumask_clear(tracing_reader_cpumask);
2733 else
2734 cpumask_clear_cpu(iter->cpu_file, tracing_reader_cpumask);
2735
2736 mutex_unlock(&trace_types_lock);
2737
2738 free_cpumask_var(iter->started);
2739 mutex_destroy(&iter->mutex);
2740 kfree(iter->trace);
2741 kfree(iter);
2742
2743 return 0;
2744 }
2745
2746 static unsigned int
2747 tracing_poll_pipe(struct file *filp, poll_table *poll_table)
2748 {
2749 struct trace_iterator *iter = filp->private_data;
2750
2751 if (trace_flags & TRACE_ITER_BLOCK) {
2752 /*
2753 * Always select as readable when in blocking mode
2754 */
2755 return POLLIN | POLLRDNORM;
2756 } else {
2757 if (!trace_empty(iter))
2758 return POLLIN | POLLRDNORM;
2759 poll_wait(filp, &trace_wait, poll_table);
2760 if (!trace_empty(iter))
2761 return POLLIN | POLLRDNORM;
2762
2763 return 0;
2764 }
2765 }
2766
2767
2768 void default_wait_pipe(struct trace_iterator *iter)
2769 {
2770 DEFINE_WAIT(wait);
2771
2772 prepare_to_wait(&trace_wait, &wait, TASK_INTERRUPTIBLE);
2773
2774 if (trace_empty(iter))
2775 schedule();
2776
2777 finish_wait(&trace_wait, &wait);
2778 }
2779
2780 /*
2781 * This is a make-shift waitqueue.
2782 * A tracer might use this callback on some rare cases:
2783 *
2784 * 1) the current tracer might hold the runqueue lock when it wakes up
2785 * a reader, hence a deadlock (sched, function, and function graph tracers)
2786 * 2) the function tracers, trace all functions, we don't want
2787 * the overhead of calling wake_up and friends
2788 * (and tracing them too)
2789 *
2790 * Anyway, this is really very primitive wakeup.
2791 */
2792 void poll_wait_pipe(struct trace_iterator *iter)
2793 {
2794 set_current_state(TASK_INTERRUPTIBLE);
2795 /* sleep for 100 msecs, and try again. */
2796 schedule_timeout(HZ / 10);
2797 }
2798
2799 /* Must be called with trace_types_lock mutex held. */
2800 static int tracing_wait_pipe(struct file *filp)
2801 {
2802 struct trace_iterator *iter = filp->private_data;
2803
2804 while (trace_empty(iter)) {
2805
2806 if ((filp->f_flags & O_NONBLOCK)) {
2807 return -EAGAIN;
2808 }
2809
2810 mutex_unlock(&iter->mutex);
2811
2812 iter->trace->wait_pipe(iter);
2813
2814 mutex_lock(&iter->mutex);
2815
2816 if (signal_pending(current))
2817 return -EINTR;
2818
2819 /*
2820 * We block until we read something and tracing is disabled.
2821 * We still block if tracing is disabled, but we have never
2822 * read anything. This allows a user to cat this file, and
2823 * then enable tracing. But after we have read something,
2824 * we give an EOF when tracing is again disabled.
2825 *
2826 * iter->pos will be 0 if we haven't read anything.
2827 */
2828 if (!tracer_enabled && iter->pos)
2829 break;
2830 }
2831
2832 return 1;
2833 }
2834
2835 /*
2836 * Consumer reader.
2837 */
2838 static ssize_t
2839 tracing_read_pipe(struct file *filp, char __user *ubuf,
2840 size_t cnt, loff_t *ppos)
2841 {
2842 struct trace_iterator *iter = filp->private_data;
2843 static struct tracer *old_tracer;
2844 ssize_t sret;
2845
2846 /* return any leftover data */
2847 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
2848 if (sret != -EBUSY)
2849 return sret;
2850
2851 trace_seq_init(&iter->seq);
2852
2853 /* copy the tracer to avoid using a global lock all around */
2854 mutex_lock(&trace_types_lock);
2855 if (unlikely(old_tracer != current_trace && current_trace)) {
2856 old_tracer = current_trace;
2857 *iter->trace = *current_trace;
2858 }
2859 mutex_unlock(&trace_types_lock);
2860
2861 /*
2862 * Avoid more than one consumer on a single file descriptor
2863 * This is just a matter of traces coherency, the ring buffer itself
2864 * is protected.
2865 */
2866 mutex_lock(&iter->mutex);
2867 if (iter->trace->read) {
2868 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
2869 if (sret)
2870 goto out;
2871 }
2872
2873 waitagain:
2874 sret = tracing_wait_pipe(filp);
2875 if (sret <= 0)
2876 goto out;
2877
2878 /* stop when tracing is finished */
2879 if (trace_empty(iter)) {
2880 sret = 0;
2881 goto out;
2882 }
2883
2884 if (cnt >= PAGE_SIZE)
2885 cnt = PAGE_SIZE - 1;
2886
2887 /* reset all but tr, trace, and overruns */
2888 memset(&iter->seq, 0,
2889 sizeof(struct trace_iterator) -
2890 offsetof(struct trace_iterator, seq));
2891 iter->pos = -1;
2892
2893 while (find_next_entry_inc(iter) != NULL) {
2894 enum print_line_t ret;
2895 int len = iter->seq.len;
2896
2897 ret = print_trace_line(iter);
2898 if (ret == TRACE_TYPE_PARTIAL_LINE) {
2899 /* don't print partial lines */
2900 iter->seq.len = len;
2901 break;
2902 }
2903 if (ret != TRACE_TYPE_NO_CONSUME)
2904 trace_consume(iter);
2905
2906 if (iter->seq.len >= cnt)
2907 break;
2908 }
2909
2910 /* Now copy what we have to the user */
2911 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
2912 if (iter->seq.readpos >= iter->seq.len)
2913 trace_seq_init(&iter->seq);
2914
2915 /*
2916 * If there was nothing to send to user, inspite of consuming trace
2917 * entries, go back to wait for more entries.
2918 */
2919 if (sret == -EBUSY)
2920 goto waitagain;
2921
2922 out:
2923 mutex_unlock(&iter->mutex);
2924
2925 return sret;
2926 }
2927
2928 static void tracing_pipe_buf_release(struct pipe_inode_info *pipe,
2929 struct pipe_buffer *buf)
2930 {
2931 __free_page(buf->page);
2932 }
2933
2934 static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
2935 unsigned int idx)
2936 {
2937 __free_page(spd->pages[idx]);
2938 }
2939
2940 static struct pipe_buf_operations tracing_pipe_buf_ops = {
2941 .can_merge = 0,
2942 .map = generic_pipe_buf_map,
2943 .unmap = generic_pipe_buf_unmap,
2944 .confirm = generic_pipe_buf_confirm,
2945 .release = tracing_pipe_buf_release,
2946 .steal = generic_pipe_buf_steal,
2947 .get = generic_pipe_buf_get,
2948 };
2949
2950 static size_t
2951 tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
2952 {
2953 size_t count;
2954 int ret;
2955
2956 /* Seq buffer is page-sized, exactly what we need. */
2957 for (;;) {
2958 count = iter->seq.len;
2959 ret = print_trace_line(iter);
2960 count = iter->seq.len - count;
2961 if (rem < count) {
2962 rem = 0;
2963 iter->seq.len -= count;
2964 break;
2965 }
2966 if (ret == TRACE_TYPE_PARTIAL_LINE) {
2967 iter->seq.len -= count;
2968 break;
2969 }
2970
2971 trace_consume(iter);
2972 rem -= count;
2973 if (!find_next_entry_inc(iter)) {
2974 rem = 0;
2975 iter->ent = NULL;
2976 break;
2977 }
2978 }
2979
2980 return rem;
2981 }
2982
2983 static ssize_t tracing_splice_read_pipe(struct file *filp,
2984 loff_t *ppos,
2985 struct pipe_inode_info *pipe,
2986 size_t len,
2987 unsigned int flags)
2988 {
2989 struct page *pages[PIPE_BUFFERS];
2990 struct partial_page partial[PIPE_BUFFERS];
2991 struct trace_iterator *iter = filp->private_data;
2992 struct splice_pipe_desc spd = {
2993 .pages = pages,
2994 .partial = partial,
2995 .nr_pages = 0, /* This gets updated below. */
2996 .flags = flags,
2997 .ops = &tracing_pipe_buf_ops,
2998 .spd_release = tracing_spd_release_pipe,
2999 };
3000 static struct tracer *old_tracer;
3001 ssize_t ret;
3002 size_t rem;
3003 unsigned int i;
3004
3005 /* copy the tracer to avoid using a global lock all around */
3006 mutex_lock(&trace_types_lock);
3007 if (unlikely(old_tracer != current_trace && current_trace)) {
3008 old_tracer = current_trace;
3009 *iter->trace = *current_trace;
3010 }
3011 mutex_unlock(&trace_types_lock);
3012
3013 mutex_lock(&iter->mutex);
3014
3015 if (iter->trace->splice_read) {
3016 ret = iter->trace->splice_read(iter, filp,
3017 ppos, pipe, len, flags);
3018 if (ret)
3019 goto out_err;
3020 }
3021
3022 ret = tracing_wait_pipe(filp);
3023 if (ret <= 0)
3024 goto out_err;
3025
3026 if (!iter->ent && !find_next_entry_inc(iter)) {
3027 ret = -EFAULT;
3028 goto out_err;
3029 }
3030
3031 /* Fill as many pages as possible. */
3032 for (i = 0, rem = len; i < PIPE_BUFFERS && rem; i++) {
3033 pages[i] = alloc_page(GFP_KERNEL);
3034 if (!pages[i])
3035 break;
3036
3037 rem = tracing_fill_pipe_page(rem, iter);
3038
3039 /* Copy the data into the page, so we can start over. */
3040 ret = trace_seq_to_buffer(&iter->seq,
3041 page_address(pages[i]),
3042 iter->seq.len);
3043 if (ret < 0) {
3044 __free_page(pages[i]);
3045 break;
3046 }
3047 partial[i].offset = 0;
3048 partial[i].len = iter->seq.len;
3049
3050 trace_seq_init(&iter->seq);
3051 }
3052
3053 mutex_unlock(&iter->mutex);
3054
3055 spd.nr_pages = i;
3056
3057 return splice_to_pipe(pipe, &spd);
3058
3059 out_err:
3060 mutex_unlock(&iter->mutex);
3061
3062 return ret;
3063 }
3064
3065 static ssize_t
3066 tracing_entries_read(struct file *filp, char __user *ubuf,
3067 size_t cnt, loff_t *ppos)
3068 {
3069 struct trace_array *tr = filp->private_data;
3070 char buf[96];
3071 int r;
3072
3073 mutex_lock(&trace_types_lock);
3074 if (!ring_buffer_expanded)
3075 r = sprintf(buf, "%lu (expanded: %lu)\n",
3076 tr->entries >> 10,
3077 trace_buf_size >> 10);
3078 else
3079 r = sprintf(buf, "%lu\n", tr->entries >> 10);
3080 mutex_unlock(&trace_types_lock);
3081
3082 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3083 }
3084
3085 static ssize_t
3086 tracing_entries_write(struct file *filp, const char __user *ubuf,
3087 size_t cnt, loff_t *ppos)
3088 {
3089 unsigned long val;
3090 char buf[64];
3091 int ret, cpu;
3092
3093 if (cnt >= sizeof(buf))
3094 return -EINVAL;
3095
3096 if (copy_from_user(&buf, ubuf, cnt))
3097 return -EFAULT;
3098
3099 buf[cnt] = 0;
3100
3101 ret = strict_strtoul(buf, 10, &val);
3102 if (ret < 0)
3103 return ret;
3104
3105 /* must have at least 1 entry */
3106 if (!val)
3107 return -EINVAL;
3108
3109 mutex_lock(&trace_types_lock);
3110
3111 tracing_stop();
3112
3113 /* disable all cpu buffers */
3114 for_each_tracing_cpu(cpu) {
3115 if (global_trace.data[cpu])
3116 atomic_inc(&global_trace.data[cpu]->disabled);
3117 if (max_tr.data[cpu])
3118 atomic_inc(&max_tr.data[cpu]->disabled);
3119 }
3120
3121 /* value is in KB */
3122 val <<= 10;
3123
3124 if (val != global_trace.entries) {
3125 ret = tracing_resize_ring_buffer(val);
3126 if (ret < 0) {
3127 cnt = ret;
3128 goto out;
3129 }
3130 }
3131
3132 filp->f_pos += cnt;
3133
3134 /* If check pages failed, return ENOMEM */
3135 if (tracing_disabled)
3136 cnt = -ENOMEM;
3137 out:
3138 for_each_tracing_cpu(cpu) {
3139 if (global_trace.data[cpu])
3140 atomic_dec(&global_trace.data[cpu]->disabled);
3141 if (max_tr.data[cpu])
3142 atomic_dec(&max_tr.data[cpu]->disabled);
3143 }
3144
3145 tracing_start();
3146 max_tr.entries = global_trace.entries;
3147 mutex_unlock(&trace_types_lock);
3148
3149 return cnt;
3150 }
3151
3152 static int mark_printk(const char *fmt, ...)
3153 {
3154 int ret;
3155 va_list args;
3156 va_start(args, fmt);
3157 ret = trace_vprintk(0, -1, fmt, args);
3158 va_end(args);
3159 return ret;
3160 }
3161
3162 static ssize_t
3163 tracing_mark_write(struct file *filp, const char __user *ubuf,
3164 size_t cnt, loff_t *fpos)
3165 {
3166 char *buf;
3167 char *end;
3168
3169 if (tracing_disabled)
3170 return -EINVAL;
3171
3172 if (cnt > TRACE_BUF_SIZE)
3173 cnt = TRACE_BUF_SIZE;
3174
3175 buf = kmalloc(cnt + 1, GFP_KERNEL);
3176 if (buf == NULL)
3177 return -ENOMEM;
3178
3179 if (copy_from_user(buf, ubuf, cnt)) {
3180 kfree(buf);
3181 return -EFAULT;
3182 }
3183
3184 /* Cut from the first nil or newline. */
3185 buf[cnt] = '\0';
3186 end = strchr(buf, '\n');
3187 if (end)
3188 *end = '\0';
3189
3190 cnt = mark_printk("%s\n", buf);
3191 kfree(buf);
3192 *fpos += cnt;
3193
3194 return cnt;
3195 }
3196
3197 static const struct file_operations tracing_max_lat_fops = {
3198 .open = tracing_open_generic,
3199 .read = tracing_max_lat_read,
3200 .write = tracing_max_lat_write,
3201 };
3202
3203 static const struct file_operations tracing_ctrl_fops = {
3204 .open = tracing_open_generic,
3205 .read = tracing_ctrl_read,
3206 .write = tracing_ctrl_write,
3207 };
3208
3209 static const struct file_operations set_tracer_fops = {
3210 .open = tracing_open_generic,
3211 .read = tracing_set_trace_read,
3212 .write = tracing_set_trace_write,
3213 };
3214
3215 static const struct file_operations tracing_pipe_fops = {
3216 .open = tracing_open_pipe,
3217 .poll = tracing_poll_pipe,
3218 .read = tracing_read_pipe,
3219 .splice_read = tracing_splice_read_pipe,
3220 .release = tracing_release_pipe,
3221 };
3222
3223 static const struct file_operations tracing_entries_fops = {
3224 .open = tracing_open_generic,
3225 .read = tracing_entries_read,
3226 .write = tracing_entries_write,
3227 };
3228
3229 static const struct file_operations tracing_mark_fops = {
3230 .open = tracing_open_generic,
3231 .write = tracing_mark_write,
3232 };
3233
3234 struct ftrace_buffer_info {
3235 struct trace_array *tr;
3236 void *spare;
3237 int cpu;
3238 unsigned int read;
3239 };
3240
3241 static int tracing_buffers_open(struct inode *inode, struct file *filp)
3242 {
3243 int cpu = (int)(long)inode->i_private;
3244 struct ftrace_buffer_info *info;
3245
3246 if (tracing_disabled)
3247 return -ENODEV;
3248
3249 info = kzalloc(sizeof(*info), GFP_KERNEL);
3250 if (!info)
3251 return -ENOMEM;
3252
3253 info->tr = &global_trace;
3254 info->cpu = cpu;
3255 info->spare = ring_buffer_alloc_read_page(info->tr->buffer);
3256 /* Force reading ring buffer for first read */
3257 info->read = (unsigned int)-1;
3258 if (!info->spare)
3259 goto out;
3260
3261 filp->private_data = info;
3262
3263 return 0;
3264
3265 out:
3266 kfree(info);
3267 return -ENOMEM;
3268 }
3269
3270 static ssize_t
3271 tracing_buffers_read(struct file *filp, char __user *ubuf,
3272 size_t count, loff_t *ppos)
3273 {
3274 struct ftrace_buffer_info *info = filp->private_data;
3275 unsigned int pos;
3276 ssize_t ret;
3277 size_t size;
3278
3279 if (!count)
3280 return 0;
3281
3282 /* Do we have previous read data to read? */
3283 if (info->read < PAGE_SIZE)
3284 goto read;
3285
3286 info->read = 0;
3287
3288 ret = ring_buffer_read_page(info->tr->buffer,
3289 &info->spare,
3290 count,
3291 info->cpu, 0);
3292 if (ret < 0)
3293 return 0;
3294
3295 pos = ring_buffer_page_len(info->spare);
3296
3297 if (pos < PAGE_SIZE)
3298 memset(info->spare + pos, 0, PAGE_SIZE - pos);
3299
3300 read:
3301 size = PAGE_SIZE - info->read;
3302 if (size > count)
3303 size = count;
3304
3305 ret = copy_to_user(ubuf, info->spare + info->read, size);
3306 if (ret == size)
3307 return -EFAULT;
3308 size -= ret;
3309
3310 *ppos += size;
3311 info->read += size;
3312
3313 return size;
3314 }
3315
3316 static int tracing_buffers_release(struct inode *inode, struct file *file)
3317 {
3318 struct ftrace_buffer_info *info = file->private_data;
3319
3320 ring_buffer_free_read_page(info->tr->buffer, info->spare);
3321 kfree(info);
3322
3323 return 0;
3324 }
3325
3326 struct buffer_ref {
3327 struct ring_buffer *buffer;
3328 void *page;
3329 int ref;
3330 };
3331
3332 static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
3333 struct pipe_buffer *buf)
3334 {
3335 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
3336
3337 if (--ref->ref)
3338 return;
3339
3340 ring_buffer_free_read_page(ref->buffer, ref->page);
3341 kfree(ref);
3342 buf->private = 0;
3343 }
3344
3345 static int buffer_pipe_buf_steal(struct pipe_inode_info *pipe,
3346 struct pipe_buffer *buf)
3347 {
3348 return 1;
3349 }
3350
3351 static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
3352 struct pipe_buffer *buf)
3353 {
3354 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
3355
3356 ref->ref++;
3357 }
3358
3359 /* Pipe buffer operations for a buffer. */
3360 static struct pipe_buf_operations buffer_pipe_buf_ops = {
3361 .can_merge = 0,
3362 .map = generic_pipe_buf_map,
3363 .unmap = generic_pipe_buf_unmap,
3364 .confirm = generic_pipe_buf_confirm,
3365 .release = buffer_pipe_buf_release,
3366 .steal = buffer_pipe_buf_steal,
3367 .get = buffer_pipe_buf_get,
3368 };
3369
3370 /*
3371 * Callback from splice_to_pipe(), if we need to release some pages
3372 * at the end of the spd in case we error'ed out in filling the pipe.
3373 */
3374 static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
3375 {
3376 struct buffer_ref *ref =
3377 (struct buffer_ref *)spd->partial[i].private;
3378
3379 if (--ref->ref)
3380 return;
3381
3382 ring_buffer_free_read_page(ref->buffer, ref->page);
3383 kfree(ref);
3384 spd->partial[i].private = 0;
3385 }
3386
3387 static ssize_t
3388 tracing_buffers_splice_read(struct file *file, loff_t *ppos,
3389 struct pipe_inode_info *pipe, size_t len,
3390 unsigned int flags)
3391 {
3392 struct ftrace_buffer_info *info = file->private_data;
3393 struct partial_page partial[PIPE_BUFFERS];
3394 struct page *pages[PIPE_BUFFERS];
3395 struct splice_pipe_desc spd = {
3396 .pages = pages,
3397 .partial = partial,
3398 .flags = flags,
3399 .ops = &buffer_pipe_buf_ops,
3400 .spd_release = buffer_spd_release,
3401 };
3402 struct buffer_ref *ref;
3403 int size, i;
3404 size_t ret;
3405
3406 /*
3407 * We can't seek on a buffer input
3408 */
3409 if (unlikely(*ppos))
3410 return -ESPIPE;
3411
3412
3413 for (i = 0; i < PIPE_BUFFERS && len; i++, len -= size) {
3414 struct page *page;
3415 int r;
3416
3417 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
3418 if (!ref)
3419 break;
3420
3421 ref->buffer = info->tr->buffer;
3422 ref->page = ring_buffer_alloc_read_page(ref->buffer);
3423 if (!ref->page) {
3424 kfree(ref);
3425 break;
3426 }
3427
3428 r = ring_buffer_read_page(ref->buffer, &ref->page,
3429 len, info->cpu, 0);
3430 if (r < 0) {
3431 ring_buffer_free_read_page(ref->buffer,
3432 ref->page);
3433 kfree(ref);
3434 break;
3435 }
3436
3437 /*
3438 * zero out any left over data, this is going to
3439 * user land.
3440 */
3441 size = ring_buffer_page_len(ref->page);
3442 if (size < PAGE_SIZE)
3443 memset(ref->page + size, 0, PAGE_SIZE - size);
3444
3445 page = virt_to_page(ref->page);
3446
3447 spd.pages[i] = page;
3448 spd.partial[i].len = PAGE_SIZE;
3449 spd.partial[i].offset = 0;
3450 spd.partial[i].private = (unsigned long)ref;
3451 spd.nr_pages++;
3452 }
3453
3454 spd.nr_pages = i;
3455
3456 /* did we read anything? */
3457 if (!spd.nr_pages) {
3458 if (flags & SPLICE_F_NONBLOCK)
3459 ret = -EAGAIN;
3460 else
3461 ret = 0;
3462 /* TODO: block */
3463 return ret;
3464 }
3465
3466 ret = splice_to_pipe(pipe, &spd);
3467
3468 return ret;
3469 }
3470
3471 static const struct file_operations tracing_buffers_fops = {
3472 .open = tracing_buffers_open,
3473 .read = tracing_buffers_read,
3474 .release = tracing_buffers_release,
3475 .splice_read = tracing_buffers_splice_read,
3476 .llseek = no_llseek,
3477 };
3478
3479 #ifdef CONFIG_DYNAMIC_FTRACE
3480
3481 int __weak ftrace_arch_read_dyn_info(char *buf, int size)
3482 {
3483 return 0;
3484 }
3485
3486 static ssize_t
3487 tracing_read_dyn_info(struct file *filp, char __user *ubuf,
3488 size_t cnt, loff_t *ppos)
3489 {
3490 static char ftrace_dyn_info_buffer[1024];
3491 static DEFINE_MUTEX(dyn_info_mutex);
3492 unsigned long *p = filp->private_data;
3493 char *buf = ftrace_dyn_info_buffer;
3494 int size = ARRAY_SIZE(ftrace_dyn_info_buffer);
3495 int r;
3496
3497 mutex_lock(&dyn_info_mutex);
3498 r = sprintf(buf, "%ld ", *p);
3499
3500 r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r);
3501 buf[r++] = '\n';
3502
3503 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3504
3505 mutex_unlock(&dyn_info_mutex);
3506
3507 return r;
3508 }
3509
3510 static const struct file_operations tracing_dyn_info_fops = {
3511 .open = tracing_open_generic,
3512 .read = tracing_read_dyn_info,
3513 };
3514 #endif
3515
3516 static struct dentry *d_tracer;
3517
3518 struct dentry *tracing_init_dentry(void)
3519 {
3520 static int once;
3521
3522 if (d_tracer)
3523 return d_tracer;
3524
3525 d_tracer = debugfs_create_dir("tracing", NULL);
3526
3527 if (!d_tracer && !once) {
3528 once = 1;
3529 pr_warning("Could not create debugfs directory 'tracing'\n");
3530 return NULL;
3531 }
3532
3533 return d_tracer;
3534 }
3535
3536 static struct dentry *d_percpu;
3537
3538 struct dentry *tracing_dentry_percpu(void)
3539 {
3540 static int once;
3541 struct dentry *d_tracer;
3542
3543 if (d_percpu)
3544 return d_percpu;
3545
3546 d_tracer = tracing_init_dentry();
3547
3548 if (!d_tracer)
3549 return NULL;
3550
3551 d_percpu = debugfs_create_dir("per_cpu", d_tracer);
3552
3553 if (!d_percpu && !once) {
3554 once = 1;
3555 pr_warning("Could not create debugfs directory 'per_cpu'\n");
3556 return NULL;
3557 }
3558
3559 return d_percpu;
3560 }
3561
3562 static void tracing_init_debugfs_percpu(long cpu)
3563 {
3564 struct dentry *d_percpu = tracing_dentry_percpu();
3565 struct dentry *entry, *d_cpu;
3566 /* strlen(cpu) + MAX(log10(cpu)) + '\0' */
3567 char cpu_dir[7];
3568
3569 if (cpu > 999 || cpu < 0)
3570 return;
3571
3572 sprintf(cpu_dir, "cpu%ld", cpu);
3573 d_cpu = debugfs_create_dir(cpu_dir, d_percpu);
3574 if (!d_cpu) {
3575 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir);
3576 return;
3577 }
3578
3579 /* per cpu trace_pipe */
3580 entry = debugfs_create_file("trace_pipe", 0444, d_cpu,
3581 (void *) cpu, &tracing_pipe_fops);
3582 if (!entry)
3583 pr_warning("Could not create debugfs 'trace_pipe' entry\n");
3584
3585 /* per cpu trace */
3586 entry = debugfs_create_file("trace", 0444, d_cpu,
3587 (void *) cpu, &tracing_fops);
3588 if (!entry)
3589 pr_warning("Could not create debugfs 'trace' entry\n");
3590
3591 entry = debugfs_create_file("trace_pipe_raw", 0444, d_cpu,
3592 (void *) cpu, &tracing_buffers_fops);
3593 if (!entry)
3594 pr_warning("Could not create debugfs 'trace_pipe_raw' entry\n");
3595 }
3596
3597 #ifdef CONFIG_FTRACE_SELFTEST
3598 /* Let selftest have access to static functions in this file */
3599 #include "trace_selftest.c"
3600 #endif
3601
3602 struct trace_option_dentry {
3603 struct tracer_opt *opt;
3604 struct tracer_flags *flags;
3605 struct dentry *entry;
3606 };
3607
3608 static ssize_t
3609 trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
3610 loff_t *ppos)
3611 {
3612 struct trace_option_dentry *topt = filp->private_data;
3613 char *buf;
3614
3615 if (topt->flags->val & topt->opt->bit)
3616 buf = "1\n";
3617 else
3618 buf = "0\n";
3619
3620 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
3621 }
3622
3623 static ssize_t
3624 trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
3625 loff_t *ppos)
3626 {
3627 struct trace_option_dentry *topt = filp->private_data;
3628 unsigned long val;
3629 char buf[64];
3630 int ret;
3631
3632 if (cnt >= sizeof(buf))
3633 return -EINVAL;
3634
3635 if (copy_from_user(&buf, ubuf, cnt))
3636 return -EFAULT;
3637
3638 buf[cnt] = 0;
3639
3640 ret = strict_strtoul(buf, 10, &val);
3641 if (ret < 0)
3642 return ret;
3643
3644 ret = 0;
3645 switch (val) {
3646 case 0:
3647 /* do nothing if already cleared */
3648 if (!(topt->flags->val & topt->opt->bit))
3649 break;
3650
3651 mutex_lock(&trace_types_lock);
3652 if (current_trace->set_flag)
3653 ret = current_trace->set_flag(topt->flags->val,
3654 topt->opt->bit, 0);
3655 mutex_unlock(&trace_types_lock);
3656 if (ret)
3657 return ret;
3658 topt->flags->val &= ~topt->opt->bit;
3659 break;
3660 case 1:
3661 /* do nothing if already set */
3662 if (topt->flags->val & topt->opt->bit)
3663 break;
3664
3665 mutex_lock(&trace_types_lock);
3666 if (current_trace->set_flag)
3667 ret = current_trace->set_flag(topt->flags->val,
3668 topt->opt->bit, 1);
3669 mutex_unlock(&trace_types_lock);
3670 if (ret)
3671 return ret;
3672 topt->flags->val |= topt->opt->bit;
3673 break;
3674
3675 default:
3676 return -EINVAL;
3677 }
3678
3679 *ppos += cnt;
3680
3681 return cnt;
3682 }
3683
3684
3685 static const struct file_operations trace_options_fops = {
3686 .open = tracing_open_generic,
3687 .read = trace_options_read,
3688 .write = trace_options_write,
3689 };
3690
3691 static ssize_t
3692 trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
3693 loff_t *ppos)
3694 {
3695 long index = (long)filp->private_data;
3696 char *buf;
3697
3698 if (trace_flags & (1 << index))
3699 buf = "1\n";
3700 else
3701 buf = "0\n";
3702
3703 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
3704 }
3705
3706 static ssize_t
3707 trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
3708 loff_t *ppos)
3709 {
3710 long index = (long)filp->private_data;
3711 char buf[64];
3712 unsigned long val;
3713 int ret;
3714
3715 if (cnt >= sizeof(buf))
3716 return -EINVAL;
3717
3718 if (copy_from_user(&buf, ubuf, cnt))
3719 return -EFAULT;
3720
3721 buf[cnt] = 0;
3722
3723 ret = strict_strtoul(buf, 10, &val);
3724 if (ret < 0)
3725 return ret;
3726
3727 switch (val) {
3728 case 0:
3729 trace_flags &= ~(1 << index);
3730 break;
3731 case 1:
3732 trace_flags |= 1 << index;
3733 break;
3734
3735 default:
3736 return -EINVAL;
3737 }
3738
3739 *ppos += cnt;
3740
3741 return cnt;
3742 }
3743
3744 static const struct file_operations trace_options_core_fops = {
3745 .open = tracing_open_generic,
3746 .read = trace_options_core_read,
3747 .write = trace_options_core_write,
3748 };
3749
3750 static struct dentry *trace_options_init_dentry(void)
3751 {
3752 struct dentry *d_tracer;
3753 static struct dentry *t_options;
3754
3755 if (t_options)
3756 return t_options;
3757
3758 d_tracer = tracing_init_dentry();
3759 if (!d_tracer)
3760 return NULL;
3761
3762 t_options = debugfs_create_dir("options", d_tracer);
3763 if (!t_options) {
3764 pr_warning("Could not create debugfs directory 'options'\n");
3765 return NULL;
3766 }
3767
3768 return t_options;
3769 }
3770
3771 static void
3772 create_trace_option_file(struct trace_option_dentry *topt,
3773 struct tracer_flags *flags,
3774 struct tracer_opt *opt)
3775 {
3776 struct dentry *t_options;
3777 struct dentry *entry;
3778
3779 t_options = trace_options_init_dentry();
3780 if (!t_options)
3781 return;
3782
3783 topt->flags = flags;
3784 topt->opt = opt;
3785
3786 entry = debugfs_create_file(opt->name, 0644, t_options, topt,
3787 &trace_options_fops);
3788
3789 topt->entry = entry;
3790
3791 }
3792
3793 static struct trace_option_dentry *
3794 create_trace_option_files(struct tracer *tracer)
3795 {
3796 struct trace_option_dentry *topts;
3797 struct tracer_flags *flags;
3798 struct tracer_opt *opts;
3799 int cnt;
3800
3801 if (!tracer)
3802 return NULL;
3803
3804 flags = tracer->flags;
3805
3806 if (!flags || !flags->opts)
3807 return NULL;
3808
3809 opts = flags->opts;
3810
3811 for (cnt = 0; opts[cnt].name; cnt++)
3812 ;
3813
3814 topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
3815 if (!topts)
3816 return NULL;
3817
3818 for (cnt = 0; opts[cnt].name; cnt++)
3819 create_trace_option_file(&topts[cnt], flags,
3820 &opts[cnt]);
3821
3822 return topts;
3823 }
3824
3825 static void
3826 destroy_trace_option_files(struct trace_option_dentry *topts)
3827 {
3828 int cnt;
3829
3830 if (!topts)
3831 return;
3832
3833 for (cnt = 0; topts[cnt].opt; cnt++) {
3834 if (topts[cnt].entry)
3835 debugfs_remove(topts[cnt].entry);
3836 }
3837
3838 kfree(topts);
3839 }
3840
3841 static struct dentry *
3842 create_trace_option_core_file(const char *option, long index)
3843 {
3844 struct dentry *t_options;
3845 struct dentry *entry;
3846
3847 t_options = trace_options_init_dentry();
3848 if (!t_options)
3849 return NULL;
3850
3851 entry = debugfs_create_file(option, 0644, t_options, (void *)index,
3852 &trace_options_core_fops);
3853
3854 return entry;
3855 }
3856
3857 static __init void create_trace_options_dir(void)
3858 {
3859 struct dentry *t_options;
3860 struct dentry *entry;
3861 int i;
3862
3863 t_options = trace_options_init_dentry();
3864 if (!t_options)
3865 return;
3866
3867 for (i = 0; trace_options[i]; i++) {
3868 entry = create_trace_option_core_file(trace_options[i], i);
3869 if (!entry)
3870 pr_warning("Could not create debugfs %s entry\n",
3871 trace_options[i]);
3872 }
3873 }
3874
3875 static __init int tracer_init_debugfs(void)
3876 {
3877 struct dentry *d_tracer;
3878 struct dentry *entry;
3879 int cpu;
3880
3881 d_tracer = tracing_init_dentry();
3882
3883 entry = debugfs_create_file("tracing_enabled", 0644, d_tracer,
3884 &global_trace, &tracing_ctrl_fops);
3885 if (!entry)
3886 pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
3887
3888 entry = debugfs_create_file("trace_options", 0644, d_tracer,
3889 NULL, &tracing_iter_fops);
3890 if (!entry)
3891 pr_warning("Could not create debugfs 'trace_options' entry\n");
3892
3893 create_trace_options_dir();
3894
3895 entry = debugfs_create_file("tracing_cpumask", 0644, d_tracer,
3896 NULL, &tracing_cpumask_fops);
3897 if (!entry)
3898 pr_warning("Could not create debugfs 'tracing_cpumask' entry\n");
3899
3900 entry = debugfs_create_file("trace", 0444, d_tracer,
3901 (void *) TRACE_PIPE_ALL_CPU, &tracing_fops);
3902 if (!entry)
3903 pr_warning("Could not create debugfs 'trace' entry\n");
3904
3905 entry = debugfs_create_file("available_tracers", 0444, d_tracer,
3906 &global_trace, &show_traces_fops);
3907 if (!entry)
3908 pr_warning("Could not create debugfs 'available_tracers' entry\n");
3909
3910 entry = debugfs_create_file("current_tracer", 0444, d_tracer,
3911 &global_trace, &set_tracer_fops);
3912 if (!entry)
3913 pr_warning("Could not create debugfs 'current_tracer' entry\n");
3914
3915 entry = debugfs_create_file("tracing_max_latency", 0644, d_tracer,
3916 &tracing_max_latency,
3917 &tracing_max_lat_fops);
3918 if (!entry)
3919 pr_warning("Could not create debugfs "
3920 "'tracing_max_latency' entry\n");
3921
3922 entry = debugfs_create_file("tracing_thresh", 0644, d_tracer,
3923 &tracing_thresh, &tracing_max_lat_fops);
3924 if (!entry)
3925 pr_warning("Could not create debugfs "
3926 "'tracing_thresh' entry\n");
3927 entry = debugfs_create_file("README", 0644, d_tracer,
3928 NULL, &tracing_readme_fops);
3929 if (!entry)
3930 pr_warning("Could not create debugfs 'README' entry\n");
3931
3932 entry = debugfs_create_file("trace_pipe", 0444, d_tracer,
3933 (void *) TRACE_PIPE_ALL_CPU, &tracing_pipe_fops);
3934 if (!entry)
3935 pr_warning("Could not create debugfs "
3936 "'trace_pipe' entry\n");
3937
3938 entry = debugfs_create_file("buffer_size_kb", 0644, d_tracer,
3939 &global_trace, &tracing_entries_fops);
3940 if (!entry)
3941 pr_warning("Could not create debugfs "
3942 "'buffer_size_kb' entry\n");
3943
3944 entry = debugfs_create_file("trace_marker", 0220, d_tracer,
3945 NULL, &tracing_mark_fops);
3946 if (!entry)
3947 pr_warning("Could not create debugfs "
3948 "'trace_marker' entry\n");
3949
3950 #ifdef CONFIG_DYNAMIC_FTRACE
3951 entry = debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer,
3952 &ftrace_update_tot_cnt,
3953 &tracing_dyn_info_fops);
3954 if (!entry)
3955 pr_warning("Could not create debugfs "
3956 "'dyn_ftrace_total_info' entry\n");
3957 #endif
3958 #ifdef CONFIG_SYSPROF_TRACER
3959 init_tracer_sysprof_debugfs(d_tracer);
3960 #endif
3961
3962 for_each_tracing_cpu(cpu)
3963 tracing_init_debugfs_percpu(cpu);
3964
3965 return 0;
3966 }
3967
3968 static int trace_panic_handler(struct notifier_block *this,
3969 unsigned long event, void *unused)
3970 {
3971 if (ftrace_dump_on_oops)
3972 ftrace_dump();
3973 return NOTIFY_OK;
3974 }
3975
3976 static struct notifier_block trace_panic_notifier = {
3977 .notifier_call = trace_panic_handler,
3978 .next = NULL,
3979 .priority = 150 /* priority: INT_MAX >= x >= 0 */
3980 };
3981
3982 static int trace_die_handler(struct notifier_block *self,
3983 unsigned long val,
3984 void *data)
3985 {
3986 switch (val) {
3987 case DIE_OOPS:
3988 if (ftrace_dump_on_oops)
3989 ftrace_dump();
3990 break;
3991 default:
3992 break;
3993 }
3994 return NOTIFY_OK;
3995 }
3996
3997 static struct notifier_block trace_die_notifier = {
3998 .notifier_call = trace_die_handler,
3999 .priority = 200
4000 };
4001
4002 /*
4003 * printk is set to max of 1024, we really don't need it that big.
4004 * Nothing should be printing 1000 characters anyway.
4005 */
4006 #define TRACE_MAX_PRINT 1000
4007
4008 /*
4009 * Define here KERN_TRACE so that we have one place to modify
4010 * it if we decide to change what log level the ftrace dump
4011 * should be at.
4012 */
4013 #define KERN_TRACE KERN_EMERG
4014
4015 static void
4016 trace_printk_seq(struct trace_seq *s)
4017 {
4018 /* Probably should print a warning here. */
4019 if (s->len >= 1000)
4020 s->len = 1000;
4021
4022 /* should be zero ended, but we are paranoid. */
4023 s->buffer[s->len] = 0;
4024
4025 printk(KERN_TRACE "%s", s->buffer);
4026
4027 trace_seq_init(s);
4028 }
4029
4030 void ftrace_dump(void)
4031 {
4032 static DEFINE_SPINLOCK(ftrace_dump_lock);
4033 /* use static because iter can be a bit big for the stack */
4034 static struct trace_iterator iter;
4035 static int dump_ran;
4036 unsigned long flags;
4037 int cnt = 0, cpu;
4038
4039 /* only one dump */
4040 spin_lock_irqsave(&ftrace_dump_lock, flags);
4041 if (dump_ran)
4042 goto out;
4043
4044 dump_ran = 1;
4045
4046 /* No turning back! */
4047 tracing_off();
4048 ftrace_kill();
4049
4050 for_each_tracing_cpu(cpu) {
4051 atomic_inc(&global_trace.data[cpu]->disabled);
4052 }
4053
4054 /* don't look at user memory in panic mode */
4055 trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
4056
4057 printk(KERN_TRACE "Dumping ftrace buffer:\n");
4058
4059 /* Simulate the iterator */
4060 iter.tr = &global_trace;
4061 iter.trace = current_trace;
4062 iter.cpu_file = TRACE_PIPE_ALL_CPU;
4063
4064 /*
4065 * We need to stop all tracing on all CPUS to read the
4066 * the next buffer. This is a bit expensive, but is
4067 * not done often. We fill all what we can read,
4068 * and then release the locks again.
4069 */
4070
4071 while (!trace_empty(&iter)) {
4072
4073 if (!cnt)
4074 printk(KERN_TRACE "---------------------------------\n");
4075
4076 cnt++;
4077
4078 /* reset all but tr, trace, and overruns */
4079 memset(&iter.seq, 0,
4080 sizeof(struct trace_iterator) -
4081 offsetof(struct trace_iterator, seq));
4082 iter.iter_flags |= TRACE_FILE_LAT_FMT;
4083 iter.pos = -1;
4084
4085 if (find_next_entry_inc(&iter) != NULL) {
4086 print_trace_line(&iter);
4087 trace_consume(&iter);
4088 }
4089
4090 trace_printk_seq(&iter.seq);
4091 }
4092
4093 if (!cnt)
4094 printk(KERN_TRACE " (ftrace buffer empty)\n");
4095 else
4096 printk(KERN_TRACE "---------------------------------\n");
4097
4098 out:
4099 spin_unlock_irqrestore(&ftrace_dump_lock, flags);
4100 }
4101
4102 __init static int tracer_alloc_buffers(void)
4103 {
4104 struct trace_array_cpu *data;
4105 int ring_buf_size;
4106 int i;
4107 int ret = -ENOMEM;
4108
4109 if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
4110 goto out;
4111
4112 if (!alloc_cpumask_var(&tracing_cpumask, GFP_KERNEL))
4113 goto out_free_buffer_mask;
4114
4115 if (!alloc_cpumask_var(&tracing_reader_cpumask, GFP_KERNEL))
4116 goto out_free_tracing_cpumask;
4117
4118 /* To save memory, keep the ring buffer size to its minimum */
4119 if (ring_buffer_expanded)
4120 ring_buf_size = trace_buf_size;
4121 else
4122 ring_buf_size = 1;
4123
4124 cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
4125 cpumask_copy(tracing_cpumask, cpu_all_mask);
4126 cpumask_clear(tracing_reader_cpumask);
4127
4128 /* TODO: make the number of buffers hot pluggable with CPUS */
4129 global_trace.buffer = ring_buffer_alloc(ring_buf_size,
4130 TRACE_BUFFER_FLAGS);
4131 if (!global_trace.buffer) {
4132 printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
4133 WARN_ON(1);
4134 goto out_free_cpumask;
4135 }
4136 global_trace.entries = ring_buffer_size(global_trace.buffer);
4137
4138
4139 #ifdef CONFIG_TRACER_MAX_TRACE
4140 max_tr.buffer = ring_buffer_alloc(ring_buf_size,
4141 TRACE_BUFFER_FLAGS);
4142 if (!max_tr.buffer) {
4143 printk(KERN_ERR "tracer: failed to allocate max ring buffer!\n");
4144 WARN_ON(1);
4145 ring_buffer_free(global_trace.buffer);
4146 goto out_free_cpumask;
4147 }
4148 max_tr.entries = ring_buffer_size(max_tr.buffer);
4149 WARN_ON(max_tr.entries != global_trace.entries);
4150 #endif
4151
4152 /* Allocate the first page for all buffers */
4153 for_each_tracing_cpu(i) {
4154 data = global_trace.data[i] = &per_cpu(global_trace_cpu, i);
4155 max_tr.data[i] = &per_cpu(max_data, i);
4156 }
4157
4158 trace_init_cmdlines();
4159
4160 register_tracer(&nop_trace);
4161 current_trace = &nop_trace;
4162 #ifdef CONFIG_BOOT_TRACER
4163 register_tracer(&boot_tracer);
4164 #endif
4165 /* All seems OK, enable tracing */
4166 tracing_disabled = 0;
4167
4168 atomic_notifier_chain_register(&panic_notifier_list,
4169 &trace_panic_notifier);
4170
4171 register_die_notifier(&trace_die_notifier);
4172
4173 return 0;
4174
4175 out_free_cpumask:
4176 free_cpumask_var(tracing_reader_cpumask);
4177 out_free_tracing_cpumask:
4178 free_cpumask_var(tracing_cpumask);
4179 out_free_buffer_mask:
4180 free_cpumask_var(tracing_buffer_mask);
4181 out:
4182 return ret;
4183 }
4184
4185 __init static int clear_boot_tracer(void)
4186 {
4187 /*
4188 * The default tracer at boot buffer is an init section.
4189 * This function is called in lateinit. If we did not
4190 * find the boot tracer, then clear it out, to prevent
4191 * later registration from accessing the buffer that is
4192 * about to be freed.
4193 */
4194 if (!default_bootup_tracer)
4195 return 0;
4196
4197 printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
4198 default_bootup_tracer);
4199 default_bootup_tracer = NULL;
4200
4201 return 0;
4202 }
4203
4204 early_initcall(tracer_alloc_buffers);
4205 fs_initcall(tracer_init_debugfs);
4206 late_initcall(clear_boot_tracer);