projects/linux·blob v2.6.32 · refs

4480 lines · 99.4 KiB

1/*
2 * ring buffer based function tracer
3 *
4 * Copyright (C) 2007-2008 Steven Rostedt <[email protected]>
5 * Copyright (C) 2008 Ingo Molnar <[email protected]>
6 *
7 * Originally taken from the RT patch by:
8 * Arnaldo Carvalho de Melo <[email protected]>
9 *
10 * Based on code from the latency_tracer, that is:
11 * Copyright (C) 2004-2006 Ingo Molnar
12 * Copyright (C) 2004 William Lee Irwin III
13 */
14#include <linux/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/smp_lock.h>
21#include <linux/notifier.h>
22#include <linux/irqflags.h>
23#include <linux/debugfs.h>
24#include <linux/pagemap.h>
25#include <linux/hardirq.h>
26#include <linux/linkage.h>
27#include <linux/uaccess.h>
28#include <linux/kprobes.h>
29#include <linux/ftrace.h>
30#include <linux/module.h>
31#include <linux/percpu.h>
32#include <linux/splice.h>
33#include <linux/kdebug.h>
34#include <linux/string.h>
35#include <linux/ctype.h>
36#include <linux/init.h>
37#include <linux/poll.h>
38#include <linux/gfp.h>
39#include <linux/fs.h>
40
41#include "trace.h"
42#include "trace_output.h"
43
44#define TRACE_BUFFER_FLAGS (RB_FL_OVERWRITE)
45
46/*
47 * On boot up, the ring buffer is set to the minimum size, so that
48 * we do not waste memory on systems that are not using tracing.
49 */
50int ring_buffer_expanded;
51
52/*
53 * We need to change this state when a selftest is running.
54 * A selftest will lurk into the ring-buffer to count the
55 * entries inserted during the selftest although some concurrent
56 * insertions into the ring-buffer such as trace_printk could occurred
57 * at the same time, giving false positive or negative results.
58 */
59static bool __read_mostly tracing_selftest_running;
60
61/*
62 * If a tracer is running, we do not want to run SELFTEST.
63 */
64bool __read_mostly tracing_selftest_disabled;
65
66/* For tracers that don't implement custom flags */
67static struct tracer_opt dummy_tracer_opt[] = {
68 { }
69};
70
71static struct tracer_flags dummy_tracer_flags = {
72 .val = 0,
73 .opts = dummy_tracer_opt
74};
75
76static int dummy_set_flag(u32 old_flags, u32 bit, int set)
77{
78 return 0;
79}
80
81/*
82 * Kill all tracing for good (never come back).
83 * It is initialized to 1 but will turn to zero if the initialization
84 * of the tracer is successful. But that is the only place that sets
85 * this back to zero.
86 */
87static int tracing_disabled = 1;
88
89DEFINE_PER_CPU(local_t, ftrace_cpu_disabled);
90
91static inline void ftrace_disable_cpu(void)
92{
93 preempt_disable();
94 local_inc(&__get_cpu_var(ftrace_cpu_disabled));
95}
96
97static inline void ftrace_enable_cpu(void)
98{
99 local_dec(&__get_cpu_var(ftrace_cpu_disabled));
100 preempt_enable();
101}
102
103static cpumask_var_t __read_mostly tracing_buffer_mask;
104
105/* Define which cpu buffers are currently read in trace_pipe */
106static cpumask_var_t tracing_reader_cpumask;
107
108#define for_each_tracing_cpu(cpu) \
109 for_each_cpu(cpu, tracing_buffer_mask)
110
111/*
112 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
113 *
114 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
115 * is set, then ftrace_dump is called. This will output the contents
116 * of the ftrace buffers to the console. This is very useful for
117 * capturing traces that lead to crashes and outputing it to a
118 * serial console.
119 *
120 * It is default off, but you can enable it with either specifying
121 * "ftrace_dump_on_oops" in the kernel command line, or setting
122 * /proc/sys/kernel/ftrace_dump_on_oops to true.
123 */
124int ftrace_dump_on_oops;
125
126static int tracing_set_tracer(const char *buf);
127
128#define MAX_TRACER_SIZE 100
129static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
130static char *default_bootup_tracer;
131
132static int __init set_ftrace(char *str)
133{
134 strncpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
135 default_bootup_tracer = bootup_tracer_buf;
136 /* We are using ftrace early, expand it */
137 ring_buffer_expanded = 1;
138 return 1;
139}
140__setup("ftrace=", set_ftrace);
141
142static int __init set_ftrace_dump_on_oops(char *str)
143{
144 ftrace_dump_on_oops = 1;
145 return 1;
146}
147__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
148
149unsigned long long ns2usecs(cycle_t nsec)
150{
151 nsec += 500;
152 do_div(nsec, 1000);
153 return nsec;
154}
155
156/*
157 * The global_trace is the descriptor that holds the tracing
158 * buffers for the live tracing. For each CPU, it contains
159 * a link list of pages that will store trace entries. The
160 * page descriptor of the pages in the memory is used to hold
161 * the link list by linking the lru item in the page descriptor
162 * to each of the pages in the buffer per CPU.
163 *
164 * For each active CPU there is a data field that holds the
165 * pages for the buffer for that CPU. Each CPU has the same number
166 * of pages allocated for its buffer.
167 */
168static struct trace_array global_trace;
169
170static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
171
172int filter_current_check_discard(struct ring_buffer *buffer,
173 struct ftrace_event_call *call, void *rec,
174 struct ring_buffer_event *event)
175{
176 return filter_check_discard(call, rec, buffer, event);
177}
178EXPORT_SYMBOL_GPL(filter_current_check_discard);
179
180cycle_t ftrace_now(int cpu)
181{
182 u64 ts;
183
184 /* Early boot up does not have a buffer yet */
185 if (!global_trace.buffer)
186 return trace_clock_local();
187
188 ts = ring_buffer_time_stamp(global_trace.buffer, cpu);
189 ring_buffer_normalize_time_stamp(global_trace.buffer, cpu, &ts);
190
191 return ts;
192}
193
194/*
195 * The max_tr is used to snapshot the global_trace when a maximum
196 * latency is reached. Some tracers will use this to store a maximum
197 * trace while it continues examining live traces.
198 *
199 * The buffers for the max_tr are set up the same as the global_trace.
200 * When a snapshot is taken, the link list of the max_tr is swapped
201 * with the link list of the global_trace and the buffers are reset for
202 * the global_trace so the tracing can continue.
203 */
204static struct trace_array max_tr;
205
206static DEFINE_PER_CPU(struct trace_array_cpu, max_data);
207
208/* tracer_enabled is used to toggle activation of a tracer */
209static int tracer_enabled = 1;
210
211/**
212 * tracing_is_enabled - return tracer_enabled status
213 *
214 * This function is used by other tracers to know the status
215 * of the tracer_enabled flag. Tracers may use this function
216 * to know if it should enable their features when starting
217 * up. See irqsoff tracer for an example (start_irqsoff_tracer).
218 */
219int tracing_is_enabled(void)
220{
221 return tracer_enabled;
222}
223
224/*
225 * trace_buf_size is the size in bytes that is allocated
226 * for a buffer. Note, the number of bytes is always rounded
227 * to page size.
228 *
229 * This number is purposely set to a low number of 16384.
230 * If the dump on oops happens, it will be much appreciated
231 * to not have to wait for all that output. Anyway this can be
232 * boot time and run time configurable.
233 */
234#define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
235
236static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
237
238/* trace_types holds a link list of available tracers. */
239static struct tracer *trace_types __read_mostly;
240
241/* current_trace points to the tracer that is currently active */
242static struct tracer *current_trace __read_mostly;
243
244/*
245 * trace_types_lock is used to protect the trace_types list.
246 * This lock is also used to keep user access serialized.
247 * Accesses from userspace will grab this lock while userspace
248 * activities happen inside the kernel.
249 */
250static DEFINE_MUTEX(trace_types_lock);
251
252/* trace_wait is a waitqueue for tasks blocked on trace_poll */
253static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
254
255/* trace_flags holds trace_options default values */
256unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
257 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | TRACE_ITER_SLEEP_TIME |
258 TRACE_ITER_GRAPH_TIME;
259
260static int trace_stop_count;
261static DEFINE_SPINLOCK(tracing_start_lock);
262
263/**
264 * trace_wake_up - wake up tasks waiting for trace input
265 *
266 * Simply wakes up any task that is blocked on the trace_wait
267 * queue. These is used with trace_poll for tasks polling the trace.
268 */
269void trace_wake_up(void)
270{
271 int cpu;
272
273 if (trace_flags & TRACE_ITER_BLOCK)
274 return;
275 /*
276 * The runqueue_is_locked() can fail, but this is the best we
277 * have for now:
278 */
279 cpu = get_cpu();
280 if (!runqueue_is_locked(cpu))
281 wake_up(&trace_wait);
282 put_cpu();
283}
284
285static int __init set_buf_size(char *str)
286{
287 unsigned long buf_size;
288
289 if (!str)
290 return 0;
291 buf_size = memparse(str, &str);
292 /* nr_entries can not be zero */
293 if (buf_size == 0)
294 return 0;
295 trace_buf_size = buf_size;
296 return 1;
297}
298__setup("trace_buf_size=", set_buf_size);
299
300unsigned long nsecs_to_usecs(unsigned long nsecs)
301{
302 return nsecs / 1000;
303}
304
305/* These must match the bit postions in trace_iterator_flags */
306static const char *trace_options[] = {
307 "print-parent",
308 "sym-offset",
309 "sym-addr",
310 "verbose",
311 "raw",
312 "hex",
313 "bin",
314 "block",
315 "stacktrace",
316 "sched-tree",
317 "trace_printk",
318 "ftrace_preempt",
319 "branch",
320 "annotate",
321 "userstacktrace",
322 "sym-userobj",
323 "printk-msg-only",
324 "context-info",
325 "latency-format",
326 "sleep-time",
327 "graph-time",
328 NULL
329};
330
331static struct {
332 u64 (*func)(void);
333 const char *name;
334} trace_clocks[] = {
335 { trace_clock_local, "local" },
336 { trace_clock_global, "global" },
337};
338
339int trace_clock_id;
340
341/*
342 * trace_parser_get_init - gets the buffer for trace parser
343 */
344int trace_parser_get_init(struct trace_parser *parser, int size)
345{
346 memset(parser, 0, sizeof(*parser));
347
348 parser->buffer = kmalloc(size, GFP_KERNEL);
349 if (!parser->buffer)
350 return 1;
351
352 parser->size = size;
353 return 0;
354}
355
356/*
357 * trace_parser_put - frees the buffer for trace parser
358 */
359void trace_parser_put(struct trace_parser *parser)
360{
361 kfree(parser->buffer);
362}
363
364/*
365 * trace_get_user - reads the user input string separated by space
366 * (matched by isspace(ch))
367 *
368 * For each string found the 'struct trace_parser' is updated,
369 * and the function returns.
370 *
371 * Returns number of bytes read.
372 *
373 * See kernel/trace/trace.h for 'struct trace_parser' details.
374 */
375int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
376 size_t cnt, loff_t *ppos)
377{
378 char ch;
379 size_t read = 0;
380 ssize_t ret;
381
382 if (!*ppos)
383 trace_parser_clear(parser);
384
385 ret = get_user(ch, ubuf++);
386 if (ret)
387 goto out;
388
389 read++;
390 cnt--;
391
392 /*
393 * The parser is not finished with the last write,
394 * continue reading the user input without skipping spaces.
395 */
396 if (!parser->cont) {
397 /* skip white space */
398 while (cnt && isspace(ch)) {
399 ret = get_user(ch, ubuf++);
400 if (ret)
401 goto out;
402 read++;
403 cnt--;
404 }
405
406 /* only spaces were written */
407 if (isspace(ch)) {
408 *ppos += read;
409 ret = read;
410 goto out;
411 }
412
413 parser->idx = 0;
414 }
415
416 /* read the non-space input */
417 while (cnt && !isspace(ch)) {
418 if (parser->idx < parser->size - 1)
419 parser->buffer[parser->idx++] = ch;
420 else {
421 ret = -EINVAL;
422 goto out;
423 }
424 ret = get_user(ch, ubuf++);
425 if (ret)
426 goto out;
427 read++;
428 cnt--;
429 }
430
431 /* We either got finished input or we have to wait for another call. */
432 if (isspace(ch)) {
433 parser->buffer[parser->idx] = 0;
434 parser->cont = false;
435 } else {
436 parser->cont = true;
437 parser->buffer[parser->idx++] = ch;
438 }
439
440 *ppos += read;
441 ret = read;
442
443out:
444 return ret;
445}
446
447ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
448{
449 int len;
450 int ret;
451
452 if (!cnt)
453 return 0;
454
455 if (s->len <= s->readpos)
456 return -EBUSY;
457
458 len = s->len - s->readpos;
459 if (cnt > len)
460 cnt = len;
461 ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
462 if (ret == cnt)
463 return -EFAULT;
464
465 cnt -= ret;
466
467 s->readpos += cnt;
468 return cnt;
469}
470
471static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
472{
473 int len;
474 void *ret;
475
476 if (s->len <= s->readpos)
477 return -EBUSY;
478
479 len = s->len - s->readpos;
480 if (cnt > len)
481 cnt = len;
482 ret = memcpy(buf, s->buffer + s->readpos, cnt);
483 if (!ret)
484 return -EFAULT;
485
486 s->readpos += cnt;
487 return cnt;
488}
489
490/*
491 * ftrace_max_lock is used to protect the swapping of buffers
492 * when taking a max snapshot. The buffers themselves are
493 * protected by per_cpu spinlocks. But the action of the swap
494 * needs its own lock.
495 *
496 * This is defined as a raw_spinlock_t in order to help
497 * with performance when lockdep debugging is enabled.
498 *
499 * It is also used in other places outside the update_max_tr
500 * so it needs to be defined outside of the
501 * CONFIG_TRACER_MAX_TRACE.
502 */
503static raw_spinlock_t ftrace_max_lock =
504 (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
505
506#ifdef CONFIG_TRACER_MAX_TRACE
507unsigned long __read_mostly tracing_max_latency;
508unsigned long __read_mostly tracing_thresh;
509
510/*
511 * Copy the new maximum trace into the separate maximum-trace
512 * structure. (this way the maximum trace is permanently saved,
513 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
514 */
515static void
516__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
517{
518 struct trace_array_cpu *data = tr->data[cpu];
519 struct trace_array_cpu *max_data = tr->data[cpu];
520
521 max_tr.cpu = cpu;
522 max_tr.time_start = data->preempt_timestamp;
523
524 max_data = max_tr.data[cpu];
525 max_data->saved_latency = tracing_max_latency;
526 max_data->critical_start = data->critical_start;
527 max_data->critical_end = data->critical_end;
528
529 memcpy(data->comm, tsk->comm, TASK_COMM_LEN);
530 max_data->pid = tsk->pid;
531 max_data->uid = task_uid(tsk);
532 max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
533 max_data->policy = tsk->policy;
534 max_data->rt_priority = tsk->rt_priority;
535
536 /* record this tasks comm */
537 tracing_record_cmdline(tsk);
538}
539
540/**
541 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
542 * @tr: tracer
543 * @tsk: the task with the latency
544 * @cpu: The cpu that initiated the trace.
545 *
546 * Flip the buffers between the @tr and the max_tr and record information
547 * about which task was the cause of this latency.
548 */
549void
550update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
551{
552 struct ring_buffer *buf = tr->buffer;
553
554 if (trace_stop_count)
555 return;
556
557 WARN_ON_ONCE(!irqs_disabled());
558 __raw_spin_lock(&ftrace_max_lock);
559
560 tr->buffer = max_tr.buffer;
561 max_tr.buffer = buf;
562
563 __update_max_tr(tr, tsk, cpu);
564 __raw_spin_unlock(&ftrace_max_lock);
565}
566
567/**
568 * update_max_tr_single - only copy one trace over, and reset the rest
569 * @tr - tracer
570 * @tsk - task with the latency
571 * @cpu - the cpu of the buffer to copy.
572 *
573 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
574 */
575void
576update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
577{
578 int ret;
579
580 if (trace_stop_count)
581 return;
582
583 WARN_ON_ONCE(!irqs_disabled());
584 __raw_spin_lock(&ftrace_max_lock);
585
586 ftrace_disable_cpu();
587
588 ret = ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu);
589
590 if (ret == -EBUSY) {
591 /*
592 * We failed to swap the buffer due to a commit taking
593 * place on this CPU. We fail to record, but we reset
594 * the max trace buffer (no one writes directly to it)
595 * and flag that it failed.
596 */
597 trace_array_printk(&max_tr, _THIS_IP_,
598 "Failed to swap buffers due to commit in progress\n");
599 }
600
601 ftrace_enable_cpu();
602
603 WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
604
605 __update_max_tr(tr, tsk, cpu);
606 __raw_spin_unlock(&ftrace_max_lock);
607}
608#endif /* CONFIG_TRACER_MAX_TRACE */
609
610/**
611 * register_tracer - register a tracer with the ftrace system.
612 * @type - the plugin for the tracer
613 *
614 * Register a new plugin tracer.
615 */
616int register_tracer(struct tracer *type)
617__releases(kernel_lock)
618__acquires(kernel_lock)
619{
620 struct tracer *t;
621 int ret = 0;
622
623 if (!type->name) {
624 pr_info("Tracer must have a name\n");
625 return -1;
626 }
627
628 if (strlen(type->name) > MAX_TRACER_SIZE) {
629 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
630 return -1;
631 }
632
633 /*
634 * When this gets called we hold the BKL which means that
635 * preemption is disabled. Various trace selftests however
636 * need to disable and enable preemption for successful tests.
637 * So we drop the BKL here and grab it after the tests again.
638 */
639 unlock_kernel();
640 mutex_lock(&trace_types_lock);
641
642 tracing_selftest_running = true;
643
644 for (t = trace_types; t; t = t->next) {
645 if (strcmp(type->name, t->name) == 0) {
646 /* already found */
647 pr_info("Tracer %s already registered\n",
648 type->name);
649 ret = -1;
650 goto out;
651 }
652 }
653
654 if (!type->set_flag)
655 type->set_flag = &dummy_set_flag;
656 if (!type->flags)
657 type->flags = &dummy_tracer_flags;
658 else
659 if (!type->flags->opts)
660 type->flags->opts = dummy_tracer_opt;
661 if (!type->wait_pipe)
662 type->wait_pipe = default_wait_pipe;
663
664
665#ifdef CONFIG_FTRACE_STARTUP_TEST
666 if (type->selftest && !tracing_selftest_disabled) {
667 struct tracer *saved_tracer = current_trace;
668 struct trace_array *tr = &global_trace;
669
670 /*
671 * Run a selftest on this tracer.
672 * Here we reset the trace buffer, and set the current
673 * tracer to be this tracer. The tracer can then run some
674 * internal tracing to verify that everything is in order.
675 * If we fail, we do not register this tracer.
676 */
677 tracing_reset_online_cpus(tr);
678
679 current_trace = type;
680 /* the test is responsible for initializing and enabling */
681 pr_info("Testing tracer %s: ", type->name);
682 ret = type->selftest(type, tr);
683 /* the test is responsible for resetting too */
684 current_trace = saved_tracer;
685 if (ret) {
686 printk(KERN_CONT "FAILED!\n");
687 goto out;
688 }
689 /* Only reset on passing, to avoid touching corrupted buffers */
690 tracing_reset_online_cpus(tr);
691
692 printk(KERN_CONT "PASSED\n");
693 }
694#endif
695
696 type->next = trace_types;
697 trace_types = type;
698
699 out:
700 tracing_selftest_running = false;
701 mutex_unlock(&trace_types_lock);
702
703 if (ret || !default_bootup_tracer)
704 goto out_unlock;
705
706 if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
707 goto out_unlock;
708
709 printk(KERN_INFO "Starting tracer '%s'\n", type->name);
710 /* Do we want this tracer to start on bootup? */
711 tracing_set_tracer(type->name);
712 default_bootup_tracer = NULL;
713 /* disable other selftests, since this will break it. */
714 tracing_selftest_disabled = 1;
715#ifdef CONFIG_FTRACE_STARTUP_TEST
716 printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
717 type->name);
718#endif
719
720 out_unlock:
721 lock_kernel();
722 return ret;
723}
724
725void unregister_tracer(struct tracer *type)
726{
727 struct tracer **t;
728
729 mutex_lock(&trace_types_lock);
730 for (t = &trace_types; *t; t = &(*t)->next) {
731 if (*t == type)
732 goto found;
733 }
734 pr_info("Tracer %s not registered\n", type->name);
735 goto out;
736
737 found:
738 *t = (*t)->next;
739
740 if (type == current_trace && tracer_enabled) {
741 tracer_enabled = 0;
742 tracing_stop();
743 if (current_trace->stop)
744 current_trace->stop(&global_trace);
745 current_trace = &nop_trace;
746 }
747out:
748 mutex_unlock(&trace_types_lock);
749}
750
751static void __tracing_reset(struct trace_array *tr, int cpu)
752{
753 ftrace_disable_cpu();
754 ring_buffer_reset_cpu(tr->buffer, cpu);
755 ftrace_enable_cpu();
756}
757
758void tracing_reset(struct trace_array *tr, int cpu)
759{
760 struct ring_buffer *buffer = tr->buffer;
761
762 ring_buffer_record_disable(buffer);
763
764 /* Make sure all commits have finished */
765 synchronize_sched();
766 __tracing_reset(tr, cpu);
767
768 ring_buffer_record_enable(buffer);
769}
770
771void tracing_reset_online_cpus(struct trace_array *tr)
772{
773 struct ring_buffer *buffer = tr->buffer;
774 int cpu;
775
776 ring_buffer_record_disable(buffer);
777
778 /* Make sure all commits have finished */
779 synchronize_sched();
780
781 tr->time_start = ftrace_now(tr->cpu);
782
783 for_each_online_cpu(cpu)
784 __tracing_reset(tr, cpu);
785
786 ring_buffer_record_enable(buffer);
787}
788
789void tracing_reset_current(int cpu)
790{
791 tracing_reset(&global_trace, cpu);
792}
793
794void tracing_reset_current_online_cpus(void)
795{
796 tracing_reset_online_cpus(&global_trace);
797}
798
799#define SAVED_CMDLINES 128
800#define NO_CMDLINE_MAP UINT_MAX
801static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
802static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
803static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
804static int cmdline_idx;
805static raw_spinlock_t trace_cmdline_lock = __RAW_SPIN_LOCK_UNLOCKED;
806
807/* temporary disable recording */
808static atomic_t trace_record_cmdline_disabled __read_mostly;
809
810static void trace_init_cmdlines(void)
811{
812 memset(&map_pid_to_cmdline, NO_CMDLINE_MAP, sizeof(map_pid_to_cmdline));
813 memset(&map_cmdline_to_pid, NO_CMDLINE_MAP, sizeof(map_cmdline_to_pid));
814 cmdline_idx = 0;
815}
816
817int is_tracing_stopped(void)
818{
819 return trace_stop_count;
820}
821
822/**
823 * ftrace_off_permanent - disable all ftrace code permanently
824 *
825 * This should only be called when a serious anomally has
826 * been detected. This will turn off the function tracing,
827 * ring buffers, and other tracing utilites. It takes no
828 * locks and can be called from any context.
829 */
830void ftrace_off_permanent(void)
831{
832 tracing_disabled = 1;
833 ftrace_stop();
834 tracing_off_permanent();
835}
836
837/**
838 * tracing_start - quick start of the tracer
839 *
840 * If tracing is enabled but was stopped by tracing_stop,
841 * this will start the tracer back up.
842 */
843void tracing_start(void)
844{
845 struct ring_buffer *buffer;
846 unsigned long flags;
847
848 if (tracing_disabled)
849 return;
850
851 spin_lock_irqsave(&tracing_start_lock, flags);
852 if (--trace_stop_count) {
853 if (trace_stop_count < 0) {
854 /* Someone screwed up their debugging */
855 WARN_ON_ONCE(1);
856 trace_stop_count = 0;
857 }
858 goto out;
859 }
860
861
862 buffer = global_trace.buffer;
863 if (buffer)
864 ring_buffer_record_enable(buffer);
865
866 buffer = max_tr.buffer;
867 if (buffer)
868 ring_buffer_record_enable(buffer);
869
870 ftrace_start();
871 out:
872 spin_unlock_irqrestore(&tracing_start_lock, flags);
873}
874
875/**
876 * tracing_stop - quick stop of the tracer
877 *
878 * Light weight way to stop tracing. Use in conjunction with
879 * tracing_start.
880 */
881void tracing_stop(void)
882{
883 struct ring_buffer *buffer;
884 unsigned long flags;
885
886 ftrace_stop();
887 spin_lock_irqsave(&tracing_start_lock, flags);
888 if (trace_stop_count++)
889 goto out;
890
891 buffer = global_trace.buffer;
892 if (buffer)
893 ring_buffer_record_disable(buffer);
894
895 buffer = max_tr.buffer;
896 if (buffer)
897 ring_buffer_record_disable(buffer);
898
899 out:
900 spin_unlock_irqrestore(&tracing_start_lock, flags);
901}
902
903void trace_stop_cmdline_recording(void);
904
905static void trace_save_cmdline(struct task_struct *tsk)
906{
907 unsigned pid, idx;
908
909 if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
910 return;
911
912 /*
913 * It's not the end of the world if we don't get
914 * the lock, but we also don't want to spin
915 * nor do we want to disable interrupts,
916 * so if we miss here, then better luck next time.
917 */
918 if (!__raw_spin_trylock(&trace_cmdline_lock))
919 return;
920
921 idx = map_pid_to_cmdline[tsk->pid];
922 if (idx == NO_CMDLINE_MAP) {
923 idx = (cmdline_idx + 1) % SAVED_CMDLINES;
924
925 /*
926 * Check whether the cmdline buffer at idx has a pid
927 * mapped. We are going to overwrite that entry so we
928 * need to clear the map_pid_to_cmdline. Otherwise we
929 * would read the new comm for the old pid.
930 */
931 pid = map_cmdline_to_pid[idx];
932 if (pid != NO_CMDLINE_MAP)
933 map_pid_to_cmdline[pid] = NO_CMDLINE_MAP;
934
935 map_cmdline_to_pid[idx] = tsk->pid;
936 map_pid_to_cmdline[tsk->pid] = idx;
937
938 cmdline_idx = idx;
939 }
940
941 memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
942
943 __raw_spin_unlock(&trace_cmdline_lock);
944}
945
946void trace_find_cmdline(int pid, char comm[])
947{
948 unsigned map;
949
950 if (!pid) {
951 strcpy(comm, "<idle>");
952 return;
953 }
954
955 if (pid > PID_MAX_DEFAULT) {
956 strcpy(comm, "<...>");
957 return;
958 }
959
960 preempt_disable();
961 __raw_spin_lock(&trace_cmdline_lock);
962 map = map_pid_to_cmdline[pid];
963 if (map != NO_CMDLINE_MAP)
964 strcpy(comm, saved_cmdlines[map]);
965 else
966 strcpy(comm, "<...>");
967
968 __raw_spin_unlock(&trace_cmdline_lock);
969 preempt_enable();
970}
971
972void tracing_record_cmdline(struct task_struct *tsk)
973{
974 if (atomic_read(&trace_record_cmdline_disabled) || !tracer_enabled ||
975 !tracing_is_on())
976 return;
977
978 trace_save_cmdline(tsk);
979}
980
981void
982tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
983 int pc)
984{
985 struct task_struct *tsk = current;
986
987 entry->preempt_count = pc & 0xff;
988 entry->pid = (tsk) ? tsk->pid : 0;
989 entry->lock_depth = (tsk) ? tsk->lock_depth : 0;
990 entry->flags =
991#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
992 (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
993#else
994 TRACE_FLAG_IRQS_NOSUPPORT |
995#endif
996 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
997 ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
998 (need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
999}
1000EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
1001
1002struct ring_buffer_event *
1003trace_buffer_lock_reserve(struct ring_buffer *buffer,
1004 int type,
1005 unsigned long len,
1006 unsigned long flags, int pc)
1007{
1008 struct ring_buffer_event *event;
1009
1010 event = ring_buffer_lock_reserve(buffer, len);
1011 if (event != NULL) {
1012 struct trace_entry *ent = ring_buffer_event_data(event);
1013
1014 tracing_generic_entry_update(ent, flags, pc);
1015 ent->type = type;
1016 }
1017
1018 return event;
1019}
1020
1021static inline void
1022__trace_buffer_unlock_commit(struct ring_buffer *buffer,
1023 struct ring_buffer_event *event,
1024 unsigned long flags, int pc,
1025 int wake)
1026{
1027 ring_buffer_unlock_commit(buffer, event);
1028
1029 ftrace_trace_stack(buffer, flags, 6, pc);
1030 ftrace_trace_userstack(buffer, flags, pc);
1031
1032 if (wake)
1033 trace_wake_up();
1034}
1035
1036void trace_buffer_unlock_commit(struct ring_buffer *buffer,
1037 struct ring_buffer_event *event,
1038 unsigned long flags, int pc)
1039{
1040 __trace_buffer_unlock_commit(buffer, event, flags, pc, 1);
1041}
1042
1043struct ring_buffer_event *
1044trace_current_buffer_lock_reserve(struct ring_buffer **current_rb,
1045 int type, unsigned long len,
1046 unsigned long flags, int pc)
1047{
1048 *current_rb = global_trace.buffer;
1049 return trace_buffer_lock_reserve(*current_rb,
1050 type, len, flags, pc);
1051}
1052EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve);
1053
1054void trace_current_buffer_unlock_commit(struct ring_buffer *buffer,
1055 struct ring_buffer_event *event,
1056 unsigned long flags, int pc)
1057{
1058 __trace_buffer_unlock_commit(buffer, event, flags, pc, 1);
1059}
1060EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit);
1061
1062void trace_nowake_buffer_unlock_commit(struct ring_buffer *buffer,
1063 struct ring_buffer_event *event,
1064 unsigned long flags, int pc)
1065{
1066 __trace_buffer_unlock_commit(buffer, event, flags, pc, 0);
1067}
1068EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit);
1069
1070void trace_current_buffer_discard_commit(struct ring_buffer *buffer,
1071 struct ring_buffer_event *event)
1072{
1073 ring_buffer_discard_commit(buffer, event);
1074}
1075EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit);
1076
1077void
1078trace_function(struct trace_array *tr,
1079 unsigned long ip, unsigned long parent_ip, unsigned long flags,
1080 int pc)
1081{
1082 struct ftrace_event_call *call = &event_function;
1083 struct ring_buffer *buffer = tr->buffer;
1084 struct ring_buffer_event *event;
1085 struct ftrace_entry *entry;
1086
1087 /* If we are reading the ring buffer, don't trace */
1088 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
1089 return;
1090
1091 event = trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
1092 flags, pc);
1093 if (!event)
1094 return;
1095 entry = ring_buffer_event_data(event);
1096 entry->ip = ip;
1097 entry->parent_ip = parent_ip;
1098
1099 if (!filter_check_discard(call, entry, buffer, event))
1100 ring_buffer_unlock_commit(buffer, event);
1101}
1102
1103void
1104ftrace(struct trace_array *tr, struct trace_array_cpu *data,
1105 unsigned long ip, unsigned long parent_ip, unsigned long flags,
1106 int pc)
1107{
1108 if (likely(!atomic_read(&data->disabled)))
1109 trace_function(tr, ip, parent_ip, flags, pc);
1110}
1111
1112#ifdef CONFIG_STACKTRACE
1113static void __ftrace_trace_stack(struct ring_buffer *buffer,
1114 unsigned long flags,
1115 int skip, int pc)
1116{
1117 struct ftrace_event_call *call = &event_kernel_stack;
1118 struct ring_buffer_event *event;
1119 struct stack_entry *entry;
1120 struct stack_trace trace;
1121
1122 event = trace_buffer_lock_reserve(buffer, TRACE_STACK,
1123 sizeof(*entry), flags, pc);
1124 if (!event)
1125 return;
1126 entry = ring_buffer_event_data(event);
1127 memset(&entry->caller, 0, sizeof(entry->caller));
1128
1129 trace.nr_entries = 0;
1130 trace.max_entries = FTRACE_STACK_ENTRIES;
1131 trace.skip = skip;
1132 trace.entries = entry->caller;
1133
1134 save_stack_trace(&trace);
1135 if (!filter_check_discard(call, entry, buffer, event))
1136 ring_buffer_unlock_commit(buffer, event);
1137}
1138
1139void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags,
1140 int skip, int pc)
1141{
1142 if (!(trace_flags & TRACE_ITER_STACKTRACE))
1143 return;
1144
1145 __ftrace_trace_stack(buffer, flags, skip, pc);
1146}
1147
1148void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
1149 int pc)
1150{
1151 __ftrace_trace_stack(tr->buffer, flags, skip, pc);
1152}
1153
1154void
1155ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
1156{
1157 struct ftrace_event_call *call = &event_user_stack;
1158 struct ring_buffer_event *event;
1159 struct userstack_entry *entry;
1160 struct stack_trace trace;
1161
1162 if (!(trace_flags & TRACE_ITER_USERSTACKTRACE))
1163 return;
1164
1165 event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
1166 sizeof(*entry), flags, pc);
1167 if (!event)
1168 return;
1169 entry = ring_buffer_event_data(event);
1170
1171 entry->tgid = current->tgid;
1172 memset(&entry->caller, 0, sizeof(entry->caller));
1173
1174 trace.nr_entries = 0;
1175 trace.max_entries = FTRACE_STACK_ENTRIES;
1176 trace.skip = 0;
1177 trace.entries = entry->caller;
1178
1179 save_stack_trace_user(&trace);
1180 if (!filter_check_discard(call, entry, buffer, event))
1181 ring_buffer_unlock_commit(buffer, event);
1182}
1183
1184#ifdef UNUSED
1185static void __trace_userstack(struct trace_array *tr, unsigned long flags)
1186{
1187 ftrace_trace_userstack(tr, flags, preempt_count());
1188}
1189#endif /* UNUSED */
1190
1191#endif /* CONFIG_STACKTRACE */
1192
1193static void
1194ftrace_trace_special(void *__tr,
1195 unsigned long arg1, unsigned long arg2, unsigned long arg3,
1196 int pc)
1197{
1198 struct ftrace_event_call *call = &event_special;
1199 struct ring_buffer_event *event;
1200 struct trace_array *tr = __tr;
1201 struct ring_buffer *buffer = tr->buffer;
1202 struct special_entry *entry;
1203
1204 event = trace_buffer_lock_reserve(buffer, TRACE_SPECIAL,
1205 sizeof(*entry), 0, pc);
1206 if (!event)
1207 return;
1208 entry = ring_buffer_event_data(event);
1209 entry->arg1 = arg1;
1210 entry->arg2 = arg2;
1211 entry->arg3 = arg3;
1212
1213 if (!filter_check_discard(call, entry, buffer, event))
1214 trace_buffer_unlock_commit(buffer, event, 0, pc);
1215}
1216
1217void
1218__trace_special(void *__tr, void *__data,
1219 unsigned long arg1, unsigned long arg2, unsigned long arg3)
1220{
1221 ftrace_trace_special(__tr, arg1, arg2, arg3, preempt_count());
1222}
1223
1224void
1225ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3)
1226{
1227 struct trace_array *tr = &global_trace;
1228 struct trace_array_cpu *data;
1229 unsigned long flags;
1230 int cpu;
1231 int pc;
1232
1233 if (tracing_disabled)
1234 return;
1235
1236 pc = preempt_count();
1237 local_irq_save(flags);
1238 cpu = raw_smp_processor_id();
1239 data = tr->data[cpu];
1240
1241 if (likely(atomic_inc_return(&data->disabled) == 1))
1242 ftrace_trace_special(tr, arg1, arg2, arg3, pc);
1243
1244 atomic_dec(&data->disabled);
1245 local_irq_restore(flags);
1246}
1247
1248/**
1249 * trace_vbprintk - write binary msg to tracing buffer
1250 *
1251 */
1252int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
1253{
1254 static raw_spinlock_t trace_buf_lock =
1255 (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
1256 static u32 trace_buf[TRACE_BUF_SIZE];
1257
1258 struct ftrace_event_call *call = &event_bprint;
1259 struct ring_buffer_event *event;
1260 struct ring_buffer *buffer;
1261 struct trace_array *tr = &global_trace;
1262 struct trace_array_cpu *data;
1263 struct bprint_entry *entry;
1264 unsigned long flags;
1265 int disable;
1266 int resched;
1267 int cpu, len = 0, size, pc;
1268
1269 if (unlikely(tracing_selftest_running || tracing_disabled))
1270 return 0;
1271
1272 /* Don't pollute graph traces with trace_vprintk internals */
1273 pause_graph_tracing();
1274
1275 pc = preempt_count();
1276 resched = ftrace_preempt_disable();
1277 cpu = raw_smp_processor_id();
1278 data = tr->data[cpu];
1279
1280 disable = atomic_inc_return(&data->disabled);
1281 if (unlikely(disable != 1))
1282 goto out;
1283
1284 /* Lockdep uses trace_printk for lock tracing */
1285 local_irq_save(flags);
1286 __raw_spin_lock(&trace_buf_lock);
1287 len = vbin_printf(trace_buf, TRACE_BUF_SIZE, fmt, args);
1288
1289 if (len > TRACE_BUF_SIZE || len < 0)
1290 goto out_unlock;
1291
1292 size = sizeof(*entry) + sizeof(u32) * len;
1293 buffer = tr->buffer;
1294 event = trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
1295 flags, pc);
1296 if (!event)
1297 goto out_unlock;
1298 entry = ring_buffer_event_data(event);
1299 entry->ip = ip;
1300 entry->fmt = fmt;
1301
1302 memcpy(entry->buf, trace_buf, sizeof(u32) * len);
1303 if (!filter_check_discard(call, entry, buffer, event))
1304 ring_buffer_unlock_commit(buffer, event);
1305
1306out_unlock:
1307 __raw_spin_unlock(&trace_buf_lock);
1308 local_irq_restore(flags);
1309
1310out:
1311 atomic_dec_return(&data->disabled);
1312 ftrace_preempt_enable(resched);
1313 unpause_graph_tracing();
1314
1315 return len;
1316}
1317EXPORT_SYMBOL_GPL(trace_vbprintk);
1318
1319int trace_array_printk(struct trace_array *tr,
1320 unsigned long ip, const char *fmt, ...)
1321{
1322 int ret;
1323 va_list ap;
1324
1325 if (!(trace_flags & TRACE_ITER_PRINTK))
1326 return 0;
1327
1328 va_start(ap, fmt);
1329 ret = trace_array_vprintk(tr, ip, fmt, ap);
1330 va_end(ap);
1331 return ret;
1332}
1333
1334int trace_array_vprintk(struct trace_array *tr,
1335 unsigned long ip, const char *fmt, va_list args)
1336{
1337 static raw_spinlock_t trace_buf_lock = __RAW_SPIN_LOCK_UNLOCKED;
1338 static char trace_buf[TRACE_BUF_SIZE];
1339
1340 struct ftrace_event_call *call = &event_print;
1341 struct ring_buffer_event *event;
1342 struct ring_buffer *buffer;
1343 struct trace_array_cpu *data;
1344 int cpu, len = 0, size, pc;
1345 struct print_entry *entry;
1346 unsigned long irq_flags;
1347 int disable;
1348
1349 if (tracing_disabled || tracing_selftest_running)
1350 return 0;
1351
1352 pc = preempt_count();
1353 preempt_disable_notrace();
1354 cpu = raw_smp_processor_id();
1355 data = tr->data[cpu];
1356
1357 disable = atomic_inc_return(&data->disabled);
1358 if (unlikely(disable != 1))
1359 goto out;
1360
1361 pause_graph_tracing();
1362 raw_local_irq_save(irq_flags);
1363 __raw_spin_lock(&trace_buf_lock);
1364 len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);
1365
1366 len = min(len, TRACE_BUF_SIZE-1);
1367 trace_buf[len] = 0;
1368
1369 size = sizeof(*entry) + len + 1;
1370 buffer = tr->buffer;
1371 event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
1372 irq_flags, pc);
1373 if (!event)
1374 goto out_unlock;
1375 entry = ring_buffer_event_data(event);
1376 entry->ip = ip;
1377
1378 memcpy(&entry->buf, trace_buf, len);
1379 entry->buf[len] = 0;
1380 if (!filter_check_discard(call, entry, buffer, event))
1381 ring_buffer_unlock_commit(buffer, event);
1382
1383 out_unlock:
1384 __raw_spin_unlock(&trace_buf_lock);
1385 raw_local_irq_restore(irq_flags);
1386 unpause_graph_tracing();
1387 out:
1388 atomic_dec_return(&data->disabled);
1389 preempt_enable_notrace();
1390
1391 return len;
1392}
1393
1394int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
1395{
1396 return trace_array_vprintk(&global_trace, ip, fmt, args);
1397}
1398EXPORT_SYMBOL_GPL(trace_vprintk);
1399
1400enum trace_file_type {
1401 TRACE_FILE_LAT_FMT = 1,
1402 TRACE_FILE_ANNOTATE = 2,
1403};
1404
1405static void trace_iterator_increment(struct trace_iterator *iter)
1406{
1407 /* Don't allow ftrace to trace into the ring buffers */
1408 ftrace_disable_cpu();
1409
1410 iter->idx++;
1411 if (iter->buffer_iter[iter->cpu])
1412 ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
1413
1414 ftrace_enable_cpu();
1415}
1416
1417static struct trace_entry *
1418peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts)
1419{
1420 struct ring_buffer_event *event;
1421 struct ring_buffer_iter *buf_iter = iter->buffer_iter[cpu];
1422
1423 /* Don't allow ftrace to trace into the ring buffers */
1424 ftrace_disable_cpu();
1425
1426 if (buf_iter)
1427 event = ring_buffer_iter_peek(buf_iter, ts);
1428 else
1429 event = ring_buffer_peek(iter->tr->buffer, cpu, ts);
1430
1431 ftrace_enable_cpu();
1432
1433 return event ? ring_buffer_event_data(event) : NULL;
1434}
1435
1436static struct trace_entry *
1437__find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts)
1438{
1439 struct ring_buffer *buffer = iter->tr->buffer;
1440 struct trace_entry *ent, *next = NULL;
1441 int cpu_file = iter->cpu_file;
1442 u64 next_ts = 0, ts;
1443 int next_cpu = -1;
1444 int cpu;
1445
1446 /*
1447 * If we are in a per_cpu trace file, don't bother by iterating over
1448 * all cpu and peek directly.
1449 */
1450 if (cpu_file > TRACE_PIPE_ALL_CPU) {
1451 if (ring_buffer_empty_cpu(buffer, cpu_file))
1452 return NULL;
1453 ent = peek_next_entry(iter, cpu_file, ent_ts);
1454 if (ent_cpu)
1455 *ent_cpu = cpu_file;
1456
1457 return ent;
1458 }
1459
1460 for_each_tracing_cpu(cpu) {
1461
1462 if (ring_buffer_empty_cpu(buffer, cpu))
1463 continue;
1464
1465 ent = peek_next_entry(iter, cpu, &ts);
1466
1467 /*
1468 * Pick the entry with the smallest timestamp:
1469 */
1470 if (ent && (!next || ts < next_ts)) {
1471 next = ent;
1472 next_cpu = cpu;
1473 next_ts = ts;
1474 }
1475 }
1476
1477 if (ent_cpu)
1478 *ent_cpu = next_cpu;
1479
1480 if (ent_ts)
1481 *ent_ts = next_ts;
1482
1483 return next;
1484}
1485
1486/* Find the next real entry, without updating the iterator itself */
1487struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
1488 int *ent_cpu, u64 *ent_ts)
1489{
1490 return __find_next_entry(iter, ent_cpu, ent_ts);
1491}
1492
1493/* Find the next real entry, and increment the iterator to the next entry */
1494static void *find_next_entry_inc(struct trace_iterator *iter)
1495{
1496 iter->ent = __find_next_entry(iter, &iter->cpu, &iter->ts);
1497
1498 if (iter->ent)
1499 trace_iterator_increment(iter);
1500
1501 return iter->ent ? iter : NULL;
1502}
1503
1504static void trace_consume(struct trace_iterator *iter)
1505{
1506 /* Don't allow ftrace to trace into the ring buffers */
1507 ftrace_disable_cpu();
1508 ring_buffer_consume(iter->tr->buffer, iter->cpu, &iter->ts);
1509 ftrace_enable_cpu();
1510}
1511
1512static void *s_next(struct seq_file *m, void *v, loff_t *pos)
1513{
1514 struct trace_iterator *iter = m->private;
1515 int i = (int)*pos;
1516 void *ent;
1517
1518 (*pos)++;
1519
1520 /* can't go backwards */
1521 if (iter->idx > i)
1522 return NULL;
1523
1524 if (iter->idx < 0)
1525 ent = find_next_entry_inc(iter);
1526 else
1527 ent = iter;
1528
1529 while (ent && iter->idx < i)
1530 ent = find_next_entry_inc(iter);
1531
1532 iter->pos = *pos;
1533
1534 return ent;
1535}
1536
1537static void tracing_iter_reset(struct trace_iterator *iter, int cpu)
1538{
1539 struct trace_array *tr = iter->tr;
1540 struct ring_buffer_event *event;
1541 struct ring_buffer_iter *buf_iter;
1542 unsigned long entries = 0;
1543 u64 ts;
1544
1545 tr->data[cpu]->skipped_entries = 0;
1546
1547 if (!iter->buffer_iter[cpu])
1548 return;
1549
1550 buf_iter = iter->buffer_iter[cpu];
1551 ring_buffer_iter_reset(buf_iter);
1552
1553 /*
1554 * We could have the case with the max latency tracers
1555 * that a reset never took place on a cpu. This is evident
1556 * by the timestamp being before the start of the buffer.
1557 */
1558 while ((event = ring_buffer_iter_peek(buf_iter, &ts))) {
1559 if (ts >= iter->tr->time_start)
1560 break;
1561 entries++;
1562 ring_buffer_read(buf_iter, NULL);
1563 }
1564
1565 tr->data[cpu]->skipped_entries = entries;
1566}
1567
1568/*
1569 * No necessary locking here. The worst thing which can
1570 * happen is loosing events consumed at the same time
1571 * by a trace_pipe reader.
1572 * Other than that, we don't risk to crash the ring buffer
1573 * because it serializes the readers.
1574 *
1575 * The current tracer is copied to avoid a global locking
1576 * all around.
1577 */
1578static void *s_start(struct seq_file *m, loff_t *pos)
1579{
1580 struct trace_iterator *iter = m->private;
1581 static struct tracer *old_tracer;
1582 int cpu_file = iter->cpu_file;
1583 void *p = NULL;
1584 loff_t l = 0;
1585 int cpu;
1586
1587 /* copy the tracer to avoid using a global lock all around */
1588 mutex_lock(&trace_types_lock);
1589 if (unlikely(old_tracer != current_trace && current_trace)) {
1590 old_tracer = current_trace;
1591 *iter->trace = *current_trace;
1592 }
1593 mutex_unlock(&trace_types_lock);
1594
1595 atomic_inc(&trace_record_cmdline_disabled);
1596
1597 if (*pos != iter->pos) {
1598 iter->ent = NULL;
1599 iter->cpu = 0;
1600 iter->idx = -1;
1601
1602 ftrace_disable_cpu();
1603
1604 if (cpu_file == TRACE_PIPE_ALL_CPU) {
1605 for_each_tracing_cpu(cpu)
1606 tracing_iter_reset(iter, cpu);
1607 } else
1608 tracing_iter_reset(iter, cpu_file);
1609
1610 ftrace_enable_cpu();
1611
1612 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
1613 ;
1614
1615 } else {
1616 l = *pos - 1;
1617 p = s_next(m, p, &l);
1618 }
1619
1620 trace_event_read_lock();
1621 return p;
1622}
1623
1624static void s_stop(struct seq_file *m, void *p)
1625{
1626 atomic_dec(&trace_record_cmdline_disabled);
1627 trace_event_read_unlock();
1628}
1629
1630static void print_lat_help_header(struct seq_file *m)
1631{
1632 seq_puts(m, "# _------=> CPU# \n");
1633 seq_puts(m, "# / _-----=> irqs-off \n");
1634 seq_puts(m, "# | / _----=> need-resched \n");
1635 seq_puts(m, "# || / _---=> hardirq/softirq \n");
1636 seq_puts(m, "# ||| / _--=> preempt-depth \n");
1637 seq_puts(m, "# |||| /_--=> lock-depth \n");
1638 seq_puts(m, "# |||||/ delay \n");
1639 seq_puts(m, "# cmd pid |||||| time | caller \n");
1640 seq_puts(m, "# \\ / |||||| \\ | / \n");
1641}
1642
1643static void print_func_help_header(struct seq_file *m)
1644{
1645 seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1646 seq_puts(m, "# | | | | |\n");
1647}
1648
1649
1650static void
1651print_trace_header(struct seq_file *m, struct trace_iterator *iter)
1652{
1653 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1654 struct trace_array *tr = iter->tr;
1655 struct trace_array_cpu *data = tr->data[tr->cpu];
1656 struct tracer *type = current_trace;
1657 unsigned long entries = 0;
1658 unsigned long total = 0;
1659 unsigned long count;
1660 const char *name = "preemption";
1661 int cpu;
1662
1663 if (type)
1664 name = type->name;
1665
1666
1667 for_each_tracing_cpu(cpu) {
1668 count = ring_buffer_entries_cpu(tr->buffer, cpu);
1669 /*
1670 * If this buffer has skipped entries, then we hold all
1671 * entries for the trace and we need to ignore the
1672 * ones before the time stamp.
1673 */
1674 if (tr->data[cpu]->skipped_entries) {
1675 count -= tr->data[cpu]->skipped_entries;
1676 /* total is the same as the entries */
1677 total += count;
1678 } else
1679 total += count +
1680 ring_buffer_overrun_cpu(tr->buffer, cpu);
1681 entries += count;
1682 }
1683
1684 seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
1685 name, UTS_RELEASE);
1686 seq_puts(m, "# -----------------------------------"
1687 "---------------------------------\n");
1688 seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
1689 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1690 nsecs_to_usecs(data->saved_latency),
1691 entries,
1692 total,
1693 tr->cpu,
1694#if defined(CONFIG_PREEMPT_NONE)
1695 "server",
1696#elif defined(CONFIG_PREEMPT_VOLUNTARY)
1697 "desktop",
1698#elif defined(CONFIG_PREEMPT)
1699 "preempt",
1700#else
1701 "unknown",
1702#endif
1703 /* These are reserved for later use */
1704 0, 0, 0, 0);
1705#ifdef CONFIG_SMP
1706 seq_printf(m, " #P:%d)\n", num_online_cpus());
1707#else
1708 seq_puts(m, ")\n");
1709#endif
1710 seq_puts(m, "# -----------------\n");
1711 seq_printf(m, "# | task: %.16s-%d "
1712 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1713 data->comm, data->pid, data->uid, data->nice,
1714 data->policy, data->rt_priority);
1715 seq_puts(m, "# -----------------\n");
1716
1717 if (data->critical_start) {
1718 seq_puts(m, "# => started at: ");
1719 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
1720 trace_print_seq(m, &iter->seq);
1721 seq_puts(m, "\n# => ended at: ");
1722 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
1723 trace_print_seq(m, &iter->seq);
1724 seq_puts(m, "\n#\n");
1725 }
1726
1727 seq_puts(m, "#\n");
1728}
1729
1730static void test_cpu_buff_start(struct trace_iterator *iter)
1731{
1732 struct trace_seq *s = &iter->seq;
1733
1734 if (!(trace_flags & TRACE_ITER_ANNOTATE))
1735 return;
1736
1737 if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
1738 return;
1739
1740 if (cpumask_test_cpu(iter->cpu, iter->started))
1741 return;
1742
1743 if (iter->tr->data[iter->cpu]->skipped_entries)
1744 return;
1745
1746 cpumask_set_cpu(iter->cpu, iter->started);
1747
1748 /* Don't print started cpu buffer for the first entry of the trace */
1749 if (iter->idx > 1)
1750 trace_seq_printf(s, "##### CPU %u buffer started ####\n",
1751 iter->cpu);
1752}
1753
1754static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
1755{
1756 struct trace_seq *s = &iter->seq;
1757 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1758 struct trace_entry *entry;
1759 struct trace_event *event;
1760
1761 entry = iter->ent;
1762
1763 test_cpu_buff_start(iter);
1764
1765 event = ftrace_find_event(entry->type);
1766
1767 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1768 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
1769 if (!trace_print_lat_context(iter))
1770 goto partial;
1771 } else {
1772 if (!trace_print_context(iter))
1773 goto partial;
1774 }
1775 }
1776
1777 if (event)
1778 return event->trace(iter, sym_flags);
1779
1780 if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
1781 goto partial;
1782
1783 return TRACE_TYPE_HANDLED;
1784partial:
1785 return TRACE_TYPE_PARTIAL_LINE;
1786}
1787
1788static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
1789{
1790 struct trace_seq *s = &iter->seq;
1791 struct trace_entry *entry;
1792 struct trace_event *event;
1793
1794 entry = iter->ent;
1795
1796 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1797 if (!trace_seq_printf(s, "%d %d %llu ",
1798 entry->pid, iter->cpu, iter->ts))
1799 goto partial;
1800 }
1801
1802 event = ftrace_find_event(entry->type);
1803 if (event)
1804 return event->raw(iter, 0);
1805
1806 if (!trace_seq_printf(s, "%d ?\n", entry->type))
1807 goto partial;
1808
1809 return TRACE_TYPE_HANDLED;
1810partial:
1811 return TRACE_TYPE_PARTIAL_LINE;
1812}
1813
1814static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
1815{
1816 struct trace_seq *s = &iter->seq;
1817 unsigned char newline = '\n';
1818 struct trace_entry *entry;
1819 struct trace_event *event;
1820
1821 entry = iter->ent;
1822
1823 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1824 SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
1825 SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
1826 SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
1827 }
1828
1829 event = ftrace_find_event(entry->type);
1830 if (event) {
1831 enum print_line_t ret = event->hex(iter, 0);
1832 if (ret != TRACE_TYPE_HANDLED)
1833 return ret;
1834 }
1835
1836 SEQ_PUT_FIELD_RET(s, newline);
1837
1838 return TRACE_TYPE_HANDLED;
1839}
1840
1841static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
1842{
1843 struct trace_seq *s = &iter->seq;
1844 struct trace_entry *entry;
1845 struct trace_event *event;
1846
1847 entry = iter->ent;
1848
1849 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1850 SEQ_PUT_FIELD_RET(s, entry->pid);
1851 SEQ_PUT_FIELD_RET(s, iter->cpu);
1852 SEQ_PUT_FIELD_RET(s, iter->ts);
1853 }
1854
1855 event = ftrace_find_event(entry->type);
1856 return event ? event->binary(iter, 0) : TRACE_TYPE_HANDLED;
1857}
1858
1859static int trace_empty(struct trace_iterator *iter)
1860{
1861 int cpu;
1862
1863 /* If we are looking at one CPU buffer, only check that one */
1864 if (iter->cpu_file != TRACE_PIPE_ALL_CPU) {
1865 cpu = iter->cpu_file;
1866 if (iter->buffer_iter[cpu]) {
1867 if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
1868 return 0;
1869 } else {
1870 if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
1871 return 0;
1872 }
1873 return 1;
1874 }
1875
1876 for_each_tracing_cpu(cpu) {
1877 if (iter->buffer_iter[cpu]) {
1878 if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
1879 return 0;
1880 } else {
1881 if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
1882 return 0;
1883 }
1884 }
1885
1886 return 1;
1887}
1888
1889/* Called with trace_event_read_lock() held. */
1890static enum print_line_t print_trace_line(struct trace_iterator *iter)
1891{
1892 enum print_line_t ret;
1893
1894 if (iter->trace && iter->trace->print_line) {
1895 ret = iter->trace->print_line(iter);
1896 if (ret != TRACE_TYPE_UNHANDLED)
1897 return ret;
1898 }
1899
1900 if (iter->ent->type == TRACE_BPRINT &&
1901 trace_flags & TRACE_ITER_PRINTK &&
1902 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
1903 return trace_print_bprintk_msg_only(iter);
1904
1905 if (iter->ent->type == TRACE_PRINT &&
1906 trace_flags & TRACE_ITER_PRINTK &&
1907 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
1908 return trace_print_printk_msg_only(iter);
1909
1910 if (trace_flags & TRACE_ITER_BIN)
1911 return print_bin_fmt(iter);
1912
1913 if (trace_flags & TRACE_ITER_HEX)
1914 return print_hex_fmt(iter);
1915
1916 if (trace_flags & TRACE_ITER_RAW)
1917 return print_raw_fmt(iter);
1918
1919 return print_trace_fmt(iter);
1920}
1921
1922static int s_show(struct seq_file *m, void *v)
1923{
1924 struct trace_iterator *iter = v;
1925
1926 if (iter->ent == NULL) {
1927 if (iter->tr) {
1928 seq_printf(m, "# tracer: %s\n", iter->trace->name);
1929 seq_puts(m, "#\n");
1930 }
1931 if (iter->trace && iter->trace->print_header)
1932 iter->trace->print_header(m);
1933 else if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
1934 /* print nothing if the buffers are empty */
1935 if (trace_empty(iter))
1936 return 0;
1937 print_trace_header(m, iter);
1938 if (!(trace_flags & TRACE_ITER_VERBOSE))
1939 print_lat_help_header(m);
1940 } else {
1941 if (!(trace_flags & TRACE_ITER_VERBOSE))
1942 print_func_help_header(m);
1943 }
1944 } else {
1945 print_trace_line(iter);
1946 trace_print_seq(m, &iter->seq);
1947 }
1948
1949 return 0;
1950}
1951
1952static const struct seq_operations tracer_seq_ops = {
1953 .start = s_start,
1954 .next = s_next,
1955 .stop = s_stop,
1956 .show = s_show,
1957};
1958
1959static struct trace_iterator *
1960__tracing_open(struct inode *inode, struct file *file)
1961{
1962 long cpu_file = (long) inode->i_private;
1963 void *fail_ret = ERR_PTR(-ENOMEM);
1964 struct trace_iterator *iter;
1965 struct seq_file *m;
1966 int cpu, ret;
1967
1968 if (tracing_disabled)
1969 return ERR_PTR(-ENODEV);
1970
1971 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1972 if (!iter)
1973 return ERR_PTR(-ENOMEM);
1974
1975 /*
1976 * We make a copy of the current tracer to avoid concurrent
1977 * changes on it while we are reading.
1978 */
1979 mutex_lock(&trace_types_lock);
1980 iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
1981 if (!iter->trace)
1982 goto fail;
1983
1984 if (current_trace)
1985 *iter->trace = *current_trace;
1986
1987 if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
1988 goto fail;
1989
1990 if (current_trace && current_trace->print_max)
1991 iter->tr = &max_tr;
1992 else
1993 iter->tr = &global_trace;
1994 iter->pos = -1;
1995 mutex_init(&iter->mutex);
1996 iter->cpu_file = cpu_file;
1997
1998 /* Notify the tracer early; before we stop tracing. */
1999 if (iter->trace && iter->trace->open)
2000 iter->trace->open(iter);
2001
2002 /* Annotate start of buffers if we had overruns */
2003 if (ring_buffer_overruns(iter->tr->buffer))
2004 iter->iter_flags |= TRACE_FILE_ANNOTATE;
2005
2006 /* stop the trace while dumping */
2007 tracing_stop();
2008
2009 if (iter->cpu_file == TRACE_PIPE_ALL_CPU) {
2010 for_each_tracing_cpu(cpu) {
2011
2012 iter->buffer_iter[cpu] =
2013 ring_buffer_read_start(iter->tr->buffer, cpu);
2014 tracing_iter_reset(iter, cpu);
2015 }
2016 } else {
2017 cpu = iter->cpu_file;
2018 iter->buffer_iter[cpu] =
2019 ring_buffer_read_start(iter->tr->buffer, cpu);
2020 tracing_iter_reset(iter, cpu);
2021 }
2022
2023 ret = seq_open(file, &tracer_seq_ops);
2024 if (ret < 0) {
2025 fail_ret = ERR_PTR(ret);
2026 goto fail_buffer;
2027 }
2028
2029 m = file->private_data;
2030 m->private = iter;
2031
2032 mutex_unlock(&trace_types_lock);
2033
2034 return iter;
2035
2036 fail_buffer:
2037 for_each_tracing_cpu(cpu) {
2038 if (iter->buffer_iter[cpu])
2039 ring_buffer_read_finish(iter->buffer_iter[cpu]);
2040 }
2041 free_cpumask_var(iter->started);
2042 tracing_start();
2043 fail:
2044 mutex_unlock(&trace_types_lock);
2045 kfree(iter->trace);
2046 kfree(iter);
2047
2048 return fail_ret;
2049}
2050
2051int tracing_open_generic(struct inode *inode, struct file *filp)
2052{
2053 if (tracing_disabled)
2054 return -ENODEV;
2055
2056 filp->private_data = inode->i_private;
2057 return 0;
2058}
2059
2060static int tracing_release(struct inode *inode, struct file *file)
2061{
2062 struct seq_file *m = (struct seq_file *)file->private_data;
2063 struct trace_iterator *iter;
2064 int cpu;
2065
2066 if (!(file->f_mode & FMODE_READ))
2067 return 0;
2068
2069 iter = m->private;
2070
2071 mutex_lock(&trace_types_lock);
2072 for_each_tracing_cpu(cpu) {
2073 if (iter->buffer_iter[cpu])
2074 ring_buffer_read_finish(iter->buffer_iter[cpu]);
2075 }
2076
2077 if (iter->trace && iter->trace->close)
2078 iter->trace->close(iter);
2079
2080 /* reenable tracing if it was previously enabled */
2081 tracing_start();
2082 mutex_unlock(&trace_types_lock);
2083
2084 seq_release(inode, file);
2085 mutex_destroy(&iter->mutex);
2086 free_cpumask_var(iter->started);
2087 kfree(iter->trace);
2088 kfree(iter);
2089 return 0;
2090}
2091
2092static int tracing_open(struct inode *inode, struct file *file)
2093{
2094 struct trace_iterator *iter;
2095 int ret = 0;
2096
2097 /* If this file was open for write, then erase contents */
2098 if ((file->f_mode & FMODE_WRITE) &&
2099 (file->f_flags & O_TRUNC)) {
2100 long cpu = (long) inode->i_private;
2101
2102 if (cpu == TRACE_PIPE_ALL_CPU)
2103 tracing_reset_online_cpus(&global_trace);
2104 else
2105 tracing_reset(&global_trace, cpu);
2106 }
2107
2108 if (file->f_mode & FMODE_READ) {
2109 iter = __tracing_open(inode, file);
2110 if (IS_ERR(iter))
2111 ret = PTR_ERR(iter);
2112 else if (trace_flags & TRACE_ITER_LATENCY_FMT)
2113 iter->iter_flags |= TRACE_FILE_LAT_FMT;
2114 }
2115 return ret;
2116}
2117
2118static void *
2119t_next(struct seq_file *m, void *v, loff_t *pos)
2120{
2121 struct tracer *t = v;
2122
2123 (*pos)++;
2124
2125 if (t)
2126 t = t->next;
2127
2128 return t;
2129}
2130
2131static void *t_start(struct seq_file *m, loff_t *pos)
2132{
2133 struct tracer *t;
2134 loff_t l = 0;
2135
2136 mutex_lock(&trace_types_lock);
2137 for (t = trace_types; t && l < *pos; t = t_next(m, t, &l))
2138 ;
2139
2140 return t;
2141}
2142
2143static void t_stop(struct seq_file *m, void *p)
2144{
2145 mutex_unlock(&trace_types_lock);
2146}
2147
2148static int t_show(struct seq_file *m, void *v)
2149{
2150 struct tracer *t = v;
2151
2152 if (!t)
2153 return 0;
2154
2155 seq_printf(m, "%s", t->name);
2156 if (t->next)
2157 seq_putc(m, ' ');
2158 else
2159 seq_putc(m, '\n');
2160
2161 return 0;
2162}
2163
2164static const struct seq_operations show_traces_seq_ops = {
2165 .start = t_start,
2166 .next = t_next,
2167 .stop = t_stop,
2168 .show = t_show,
2169};
2170
2171static int show_traces_open(struct inode *inode, struct file *file)
2172{
2173 if (tracing_disabled)
2174 return -ENODEV;
2175
2176 return seq_open(file, &show_traces_seq_ops);
2177}
2178
2179static ssize_t
2180tracing_write_stub(struct file *filp, const char __user *ubuf,
2181 size_t count, loff_t *ppos)
2182{
2183 return count;
2184}
2185
2186static const struct file_operations tracing_fops = {
2187 .open = tracing_open,
2188 .read = seq_read,
2189 .write = tracing_write_stub,
2190 .llseek = seq_lseek,
2191 .release = tracing_release,
2192};
2193
2194static const struct file_operations show_traces_fops = {
2195 .open = show_traces_open,
2196 .read = seq_read,
2197 .release = seq_release,
2198};
2199
2200/*
2201 * Only trace on a CPU if the bitmask is set:
2202 */
2203static cpumask_var_t tracing_cpumask;
2204
2205/*
2206 * The tracer itself will not take this lock, but still we want
2207 * to provide a consistent cpumask to user-space:
2208 */
2209static DEFINE_MUTEX(tracing_cpumask_update_lock);
2210
2211/*
2212 * Temporary storage for the character representation of the
2213 * CPU bitmask (and one more byte for the newline):
2214 */
2215static char mask_str[NR_CPUS + 1];
2216
2217static ssize_t
2218tracing_cpumask_read(struct file *filp, char __user *ubuf,
2219 size_t count, loff_t *ppos)
2220{
2221 int len;
2222
2223 mutex_lock(&tracing_cpumask_update_lock);
2224
2225 len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
2226 if (count - len < 2) {
2227 count = -EINVAL;
2228 goto out_err;
2229 }
2230 len += sprintf(mask_str + len, "\n");
2231 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
2232
2233out_err:
2234 mutex_unlock(&tracing_cpumask_update_lock);
2235
2236 return count;
2237}
2238
2239static ssize_t
2240tracing_cpumask_write(struct file *filp, const char __user *ubuf,
2241 size_t count, loff_t *ppos)
2242{
2243 int err, cpu;
2244 cpumask_var_t tracing_cpumask_new;
2245
2246 if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
2247 return -ENOMEM;
2248
2249 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
2250 if (err)
2251 goto err_unlock;
2252
2253 mutex_lock(&tracing_cpumask_update_lock);
2254
2255 local_irq_disable();
2256 __raw_spin_lock(&ftrace_max_lock);
2257 for_each_tracing_cpu(cpu) {
2258 /*
2259 * Increase/decrease the disabled counter if we are
2260 * about to flip a bit in the cpumask:
2261 */
2262 if (cpumask_test_cpu(cpu, tracing_cpumask) &&
2263 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
2264 atomic_inc(&global_trace.data[cpu]->disabled);
2265 }
2266 if (!cpumask_test_cpu(cpu, tracing_cpumask) &&
2267 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
2268 atomic_dec(&global_trace.data[cpu]->disabled);
2269 }
2270 }
2271 __raw_spin_unlock(&ftrace_max_lock);
2272 local_irq_enable();
2273
2274 cpumask_copy(tracing_cpumask, tracing_cpumask_new);
2275
2276 mutex_unlock(&tracing_cpumask_update_lock);
2277 free_cpumask_var(tracing_cpumask_new);
2278
2279 return count;
2280
2281err_unlock:
2282 free_cpumask_var(tracing_cpumask_new);
2283
2284 return err;
2285}
2286
2287static const struct file_operations tracing_cpumask_fops = {
2288 .open = tracing_open_generic,
2289 .read = tracing_cpumask_read,
2290 .write = tracing_cpumask_write,
2291};
2292
2293static ssize_t
2294tracing_trace_options_read(struct file *filp, char __user *ubuf,
2295 size_t cnt, loff_t *ppos)
2296{
2297 struct tracer_opt *trace_opts;
2298 u32 tracer_flags;
2299 int len = 0;
2300 char *buf;
2301 int r = 0;
2302 int i;
2303
2304
2305 /* calculate max size */
2306 for (i = 0; trace_options[i]; i++) {
2307 len += strlen(trace_options[i]);
2308 len += 3; /* "no" and newline */
2309 }
2310
2311 mutex_lock(&trace_types_lock);
2312 tracer_flags = current_trace->flags->val;
2313 trace_opts = current_trace->flags->opts;
2314
2315 /*
2316 * Increase the size with names of options specific
2317 * of the current tracer.
2318 */
2319 for (i = 0; trace_opts[i].name; i++) {
2320 len += strlen(trace_opts[i].name);
2321 len += 3; /* "no" and newline */
2322 }
2323
2324 /* +1 for \0 */
2325 buf = kmalloc(len + 1, GFP_KERNEL);
2326 if (!buf) {
2327 mutex_unlock(&trace_types_lock);
2328 return -ENOMEM;
2329 }
2330
2331 for (i = 0; trace_options[i]; i++) {
2332 if (trace_flags & (1 << i))
2333 r += sprintf(buf + r, "%s\n", trace_options[i]);
2334 else
2335 r += sprintf(buf + r, "no%s\n", trace_options[i]);
2336 }
2337
2338 for (i = 0; trace_opts[i].name; i++) {
2339 if (tracer_flags & trace_opts[i].bit)
2340 r += sprintf(buf + r, "%s\n",
2341 trace_opts[i].name);
2342 else
2343 r += sprintf(buf + r, "no%s\n",
2344 trace_opts[i].name);
2345 }
2346 mutex_unlock(&trace_types_lock);
2347
2348 WARN_ON(r >= len + 1);
2349
2350 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2351
2352 kfree(buf);
2353 return r;
2354}
2355
2356/* Try to assign a tracer specific option */
2357static int set_tracer_option(struct tracer *trace, char *cmp, int neg)
2358{
2359 struct tracer_flags *tracer_flags = trace->flags;
2360 struct tracer_opt *opts = NULL;
2361 int ret = 0, i = 0;
2362 int len;
2363
2364 for (i = 0; tracer_flags->opts[i].name; i++) {
2365 opts = &tracer_flags->opts[i];
2366 len = strlen(opts->name);
2367
2368 if (strncmp(cmp, opts->name, len) == 0) {
2369 ret = trace->set_flag(tracer_flags->val,
2370 opts->bit, !neg);
2371 break;
2372 }
2373 }
2374 /* Not found */
2375 if (!tracer_flags->opts[i].name)
2376 return -EINVAL;
2377
2378 /* Refused to handle */
2379 if (ret)
2380 return ret;
2381
2382 if (neg)
2383 tracer_flags->val &= ~opts->bit;
2384 else
2385 tracer_flags->val |= opts->bit;
2386
2387 return 0;
2388}
2389
2390static void set_tracer_flags(unsigned int mask, int enabled)
2391{
2392 /* do nothing if flag is already set */
2393 if (!!(trace_flags & mask) == !!enabled)
2394 return;
2395
2396 if (enabled)
2397 trace_flags |= mask;
2398 else
2399 trace_flags &= ~mask;
2400}
2401
2402static ssize_t
2403tracing_trace_options_write(struct file *filp, const char __user *ubuf,
2404 size_t cnt, loff_t *ppos)
2405{
2406 char buf[64];
2407 char *cmp = buf;
2408 int neg = 0;
2409 int ret;
2410 int i;
2411
2412 if (cnt >= sizeof(buf))
2413 return -EINVAL;
2414
2415 if (copy_from_user(&buf, ubuf, cnt))
2416 return -EFAULT;
2417
2418 buf[cnt] = 0;
2419
2420 if (strncmp(buf, "no", 2) == 0) {
2421 neg = 1;
2422 cmp += 2;
2423 }
2424
2425 for (i = 0; trace_options[i]; i++) {
2426 int len = strlen(trace_options[i]);
2427
2428 if (strncmp(cmp, trace_options[i], len) == 0) {
2429 set_tracer_flags(1 << i, !neg);
2430 break;
2431 }
2432 }
2433
2434 /* If no option could be set, test the specific tracer options */
2435 if (!trace_options[i]) {
2436 mutex_lock(&trace_types_lock);
2437 ret = set_tracer_option(current_trace, cmp, neg);
2438 mutex_unlock(&trace_types_lock);
2439 if (ret)
2440 return ret;
2441 }
2442
2443 *ppos += cnt;
2444
2445 return cnt;
2446}
2447
2448static const struct file_operations tracing_iter_fops = {
2449 .open = tracing_open_generic,
2450 .read = tracing_trace_options_read,
2451 .write = tracing_trace_options_write,
2452};
2453
2454static const char readme_msg[] =
2455 "tracing mini-HOWTO:\n\n"
2456 "# mount -t debugfs nodev /sys/kernel/debug\n\n"
2457 "# cat /sys/kernel/debug/tracing/available_tracers\n"
2458 "wakeup preemptirqsoff preemptoff irqsoff function sched_switch nop\n\n"
2459 "# cat /sys/kernel/debug/tracing/current_tracer\n"
2460 "nop\n"
2461 "# echo sched_switch > /sys/kernel/debug/tracing/current_tracer\n"
2462 "# cat /sys/kernel/debug/tracing/current_tracer\n"
2463 "sched_switch\n"
2464 "# cat /sys/kernel/debug/tracing/trace_options\n"
2465 "noprint-parent nosym-offset nosym-addr noverbose\n"
2466 "# echo print-parent > /sys/kernel/debug/tracing/trace_options\n"
2467 "# echo 1 > /sys/kernel/debug/tracing/tracing_enabled\n"
2468 "# cat /sys/kernel/debug/tracing/trace > /tmp/trace.txt\n"
2469 "# echo 0 > /sys/kernel/debug/tracing/tracing_enabled\n"
2470;
2471
2472static ssize_t
2473tracing_readme_read(struct file *filp, char __user *ubuf,
2474 size_t cnt, loff_t *ppos)
2475{
2476 return simple_read_from_buffer(ubuf, cnt, ppos,
2477 readme_msg, strlen(readme_msg));
2478}
2479
2480static const struct file_operations tracing_readme_fops = {
2481 .open = tracing_open_generic,
2482 .read = tracing_readme_read,
2483};
2484
2485static ssize_t
2486tracing_saved_cmdlines_read(struct file *file, char __user *ubuf,
2487 size_t cnt, loff_t *ppos)
2488{
2489 char *buf_comm;
2490 char *file_buf;
2491 char *buf;
2492 int len = 0;
2493 int pid;
2494 int i;
2495
2496 file_buf = kmalloc(SAVED_CMDLINES*(16+TASK_COMM_LEN), GFP_KERNEL);
2497 if (!file_buf)
2498 return -ENOMEM;
2499
2500 buf_comm = kmalloc(TASK_COMM_LEN, GFP_KERNEL);
2501 if (!buf_comm) {
2502 kfree(file_buf);
2503 return -ENOMEM;
2504 }
2505
2506 buf = file_buf;
2507
2508 for (i = 0; i < SAVED_CMDLINES; i++) {
2509 int r;
2510
2511 pid = map_cmdline_to_pid[i];
2512 if (pid == -1 || pid == NO_CMDLINE_MAP)
2513 continue;
2514
2515 trace_find_cmdline(pid, buf_comm);
2516 r = sprintf(buf, "%d %s\n", pid, buf_comm);
2517 buf += r;
2518 len += r;
2519 }
2520
2521 len = simple_read_from_buffer(ubuf, cnt, ppos,
2522 file_buf, len);
2523
2524 kfree(file_buf);
2525 kfree(buf_comm);
2526
2527 return len;
2528}
2529
2530static const struct file_operations tracing_saved_cmdlines_fops = {
2531 .open = tracing_open_generic,
2532 .read = tracing_saved_cmdlines_read,
2533};
2534
2535static ssize_t
2536tracing_ctrl_read(struct file *filp, char __user *ubuf,
2537 size_t cnt, loff_t *ppos)
2538{
2539 char buf[64];
2540 int r;
2541
2542 r = sprintf(buf, "%u\n", tracer_enabled);
2543 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2544}
2545
2546static ssize_t
2547tracing_ctrl_write(struct file *filp, const char __user *ubuf,
2548 size_t cnt, loff_t *ppos)
2549{
2550 struct trace_array *tr = filp->private_data;
2551 char buf[64];
2552 unsigned long val;
2553 int ret;
2554
2555 if (cnt >= sizeof(buf))
2556 return -EINVAL;
2557
2558 if (copy_from_user(&buf, ubuf, cnt))
2559 return -EFAULT;
2560
2561 buf[cnt] = 0;
2562
2563 ret = strict_strtoul(buf, 10, &val);
2564 if (ret < 0)
2565 return ret;
2566
2567 val = !!val;
2568
2569 mutex_lock(&trace_types_lock);
2570 if (tracer_enabled ^ val) {
2571 if (val) {
2572 tracer_enabled = 1;
2573 if (current_trace->start)
2574 current_trace->start(tr);
2575 tracing_start();
2576 } else {
2577 tracer_enabled = 0;
2578 tracing_stop();
2579 if (current_trace->stop)
2580 current_trace->stop(tr);
2581 }
2582 }
2583 mutex_unlock(&trace_types_lock);
2584
2585 *ppos += cnt;
2586
2587 return cnt;
2588}
2589
2590static ssize_t
2591tracing_set_trace_read(struct file *filp, char __user *ubuf,
2592 size_t cnt, loff_t *ppos)
2593{
2594 char buf[MAX_TRACER_SIZE+2];
2595 int r;
2596
2597 mutex_lock(&trace_types_lock);
2598 if (current_trace)
2599 r = sprintf(buf, "%s\n", current_trace->name);
2600 else
2601 r = sprintf(buf, "\n");
2602 mutex_unlock(&trace_types_lock);
2603
2604 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2605}
2606
2607int tracer_init(struct tracer *t, struct trace_array *tr)
2608{
2609 tracing_reset_online_cpus(tr);
2610 return t->init(tr);
2611}
2612
2613static int tracing_resize_ring_buffer(unsigned long size)
2614{
2615 int ret;
2616
2617 /*
2618 * If kernel or user changes the size of the ring buffer
2619 * we use the size that was given, and we can forget about
2620 * expanding it later.
2621 */
2622 ring_buffer_expanded = 1;
2623
2624 ret = ring_buffer_resize(global_trace.buffer, size);
2625 if (ret < 0)
2626 return ret;
2627
2628 ret = ring_buffer_resize(max_tr.buffer, size);
2629 if (ret < 0) {
2630 int r;
2631
2632 r = ring_buffer_resize(global_trace.buffer,
2633 global_trace.entries);
2634 if (r < 0) {
2635 /*
2636 * AARGH! We are left with different
2637 * size max buffer!!!!
2638 * The max buffer is our "snapshot" buffer.
2639 * When a tracer needs a snapshot (one of the
2640 * latency tracers), it swaps the max buffer
2641 * with the saved snap shot. We succeeded to
2642 * update the size of the main buffer, but failed to
2643 * update the size of the max buffer. But when we tried
2644 * to reset the main buffer to the original size, we
2645 * failed there too. This is very unlikely to
2646 * happen, but if it does, warn and kill all
2647 * tracing.
2648 */
2649 WARN_ON(1);
2650 tracing_disabled = 1;
2651 }
2652 return ret;
2653 }
2654
2655 global_trace.entries = size;
2656
2657 return ret;
2658}
2659
2660/**
2661 * tracing_update_buffers - used by tracing facility to expand ring buffers
2662 *
2663 * To save on memory when the tracing is never used on a system with it
2664 * configured in. The ring buffers are set to a minimum size. But once
2665 * a user starts to use the tracing facility, then they need to grow
2666 * to their default size.
2667 *
2668 * This function is to be called when a tracer is about to be used.
2669 */
2670int tracing_update_buffers(void)
2671{
2672 int ret = 0;
2673
2674 mutex_lock(&trace_types_lock);
2675 if (!ring_buffer_expanded)
2676 ret = tracing_resize_ring_buffer(trace_buf_size);
2677 mutex_unlock(&trace_types_lock);
2678
2679 return ret;
2680}
2681
2682struct trace_option_dentry;
2683
2684static struct trace_option_dentry *
2685create_trace_option_files(struct tracer *tracer);
2686
2687static void
2688destroy_trace_option_files(struct trace_option_dentry *topts);
2689
2690static int tracing_set_tracer(const char *buf)
2691{
2692 static struct trace_option_dentry *topts;
2693 struct trace_array *tr = &global_trace;
2694 struct tracer *t;
2695 int ret = 0;
2696
2697 mutex_lock(&trace_types_lock);
2698
2699 if (!ring_buffer_expanded) {
2700 ret = tracing_resize_ring_buffer(trace_buf_size);
2701 if (ret < 0)
2702 goto out;
2703 ret = 0;
2704 }
2705
2706 for (t = trace_types; t; t = t->next) {
2707 if (strcmp(t->name, buf) == 0)
2708 break;
2709 }
2710 if (!t) {
2711 ret = -EINVAL;
2712 goto out;
2713 }
2714 if (t == current_trace)
2715 goto out;
2716
2717 trace_branch_disable();
2718 if (current_trace && current_trace->reset)
2719 current_trace->reset(tr);
2720
2721 destroy_trace_option_files(topts);
2722
2723 current_trace = t;
2724
2725 topts = create_trace_option_files(current_trace);
2726
2727 if (t->init) {
2728 ret = tracer_init(t, tr);
2729 if (ret)
2730 goto out;
2731 }
2732
2733 trace_branch_enable(tr);
2734 out:
2735 mutex_unlock(&trace_types_lock);
2736
2737 return ret;
2738}
2739
2740static ssize_t
2741tracing_set_trace_write(struct file *filp, const char __user *ubuf,
2742 size_t cnt, loff_t *ppos)
2743{
2744 char buf[MAX_TRACER_SIZE+1];
2745 int i;
2746 size_t ret;
2747 int err;
2748
2749 ret = cnt;
2750
2751 if (cnt > MAX_TRACER_SIZE)
2752 cnt = MAX_TRACER_SIZE;
2753
2754 if (copy_from_user(&buf, ubuf, cnt))
2755 return -EFAULT;
2756
2757 buf[cnt] = 0;
2758
2759 /* strip ending whitespace. */
2760 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
2761 buf[i] = 0;
2762
2763 err = tracing_set_tracer(buf);
2764 if (err)
2765 return err;
2766
2767 *ppos += ret;
2768
2769 return ret;
2770}
2771
2772static ssize_t
2773tracing_max_lat_read(struct file *filp, char __user *ubuf,
2774 size_t cnt, loff_t *ppos)
2775{
2776 unsigned long *ptr = filp->private_data;
2777 char buf[64];
2778 int r;
2779
2780 r = snprintf(buf, sizeof(buf), "%ld\n",
2781 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
2782 if (r > sizeof(buf))
2783 r = sizeof(buf);
2784 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2785}
2786
2787static ssize_t
2788tracing_max_lat_write(struct file *filp, const char __user *ubuf,
2789 size_t cnt, loff_t *ppos)
2790{
2791 unsigned long *ptr = filp->private_data;
2792 char buf[64];
2793 unsigned long val;
2794 int ret;
2795
2796 if (cnt >= sizeof(buf))
2797 return -EINVAL;
2798
2799 if (copy_from_user(&buf, ubuf, cnt))
2800 return -EFAULT;
2801
2802 buf[cnt] = 0;
2803
2804 ret = strict_strtoul(buf, 10, &val);
2805 if (ret < 0)
2806 return ret;
2807
2808 *ptr = val * 1000;
2809
2810 return cnt;
2811}
2812
2813static int tracing_open_pipe(struct inode *inode, struct file *filp)
2814{
2815 long cpu_file = (long) inode->i_private;
2816 struct trace_iterator *iter;
2817 int ret = 0;
2818
2819 if (tracing_disabled)
2820 return -ENODEV;
2821
2822 mutex_lock(&trace_types_lock);
2823
2824 /* We only allow one reader per cpu */
2825 if (cpu_file == TRACE_PIPE_ALL_CPU) {
2826 if (!cpumask_empty(tracing_reader_cpumask)) {
2827 ret = -EBUSY;
2828 goto out;
2829 }
2830 cpumask_setall(tracing_reader_cpumask);
2831 } else {
2832 if (!cpumask_test_cpu(cpu_file, tracing_reader_cpumask))
2833 cpumask_set_cpu(cpu_file, tracing_reader_cpumask);
2834 else {
2835 ret = -EBUSY;
2836 goto out;
2837 }
2838 }
2839
2840 /* create a buffer to store the information to pass to userspace */
2841 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2842 if (!iter) {
2843 ret = -ENOMEM;
2844 goto out;
2845 }
2846
2847 /*
2848 * We make a copy of the current tracer to avoid concurrent
2849 * changes on it while we are reading.
2850 */
2851 iter->trace = kmalloc(sizeof(*iter->trace), GFP_KERNEL);
2852 if (!iter->trace) {
2853 ret = -ENOMEM;
2854 goto fail;
2855 }
2856 if (current_trace)
2857 *iter->trace = *current_trace;
2858
2859 if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
2860 ret = -ENOMEM;
2861 goto fail;
2862 }
2863
2864 /* trace pipe does not show start of buffer */
2865 cpumask_setall(iter->started);
2866
2867 if (trace_flags & TRACE_ITER_LATENCY_FMT)
2868 iter->iter_flags |= TRACE_FILE_LAT_FMT;
2869
2870 iter->cpu_file = cpu_file;
2871 iter->tr = &global_trace;
2872 mutex_init(&iter->mutex);
2873 filp->private_data = iter;
2874
2875 if (iter->trace->pipe_open)
2876 iter->trace->pipe_open(iter);
2877
2878out:
2879 mutex_unlock(&trace_types_lock);
2880 return ret;
2881
2882fail:
2883 kfree(iter->trace);
2884 kfree(iter);
2885 mutex_unlock(&trace_types_lock);
2886 return ret;
2887}
2888
2889static int tracing_release_pipe(struct inode *inode, struct file *file)
2890{
2891 struct trace_iterator *iter = file->private_data;
2892
2893 mutex_lock(&trace_types_lock);
2894
2895 if (iter->cpu_file == TRACE_PIPE_ALL_CPU)
2896 cpumask_clear(tracing_reader_cpumask);
2897 else
2898 cpumask_clear_cpu(iter->cpu_file, tracing_reader_cpumask);
2899
2900 mutex_unlock(&trace_types_lock);
2901
2902 free_cpumask_var(iter->started);
2903 mutex_destroy(&iter->mutex);
2904 kfree(iter->trace);
2905 kfree(iter);
2906
2907 return 0;
2908}
2909
2910static unsigned int
2911tracing_poll_pipe(struct file *filp, poll_table *poll_table)
2912{
2913 struct trace_iterator *iter = filp->private_data;
2914
2915 if (trace_flags & TRACE_ITER_BLOCK) {
2916 /*
2917 * Always select as readable when in blocking mode
2918 */
2919 return POLLIN | POLLRDNORM;
2920 } else {
2921 if (!trace_empty(iter))
2922 return POLLIN | POLLRDNORM;
2923 poll_wait(filp, &trace_wait, poll_table);
2924 if (!trace_empty(iter))
2925 return POLLIN | POLLRDNORM;
2926
2927 return 0;
2928 }
2929}
2930
2931
2932void default_wait_pipe(struct trace_iterator *iter)
2933{
2934 DEFINE_WAIT(wait);
2935
2936 prepare_to_wait(&trace_wait, &wait, TASK_INTERRUPTIBLE);
2937
2938 if (trace_empty(iter))
2939 schedule();
2940
2941 finish_wait(&trace_wait, &wait);
2942}
2943
2944/*
2945 * This is a make-shift waitqueue.
2946 * A tracer might use this callback on some rare cases:
2947 *
2948 * 1) the current tracer might hold the runqueue lock when it wakes up
2949 * a reader, hence a deadlock (sched, function, and function graph tracers)
2950 * 2) the function tracers, trace all functions, we don't want
2951 * the overhead of calling wake_up and friends
2952 * (and tracing them too)
2953 *
2954 * Anyway, this is really very primitive wakeup.
2955 */
2956void poll_wait_pipe(struct trace_iterator *iter)
2957{
2958 set_current_state(TASK_INTERRUPTIBLE);
2959 /* sleep for 100 msecs, and try again. */
2960 schedule_timeout(HZ / 10);
2961}
2962
2963/* Must be called with trace_types_lock mutex held. */
2964static int tracing_wait_pipe(struct file *filp)
2965{
2966 struct trace_iterator *iter = filp->private_data;
2967
2968 while (trace_empty(iter)) {
2969
2970 if ((filp->f_flags & O_NONBLOCK)) {
2971 return -EAGAIN;
2972 }
2973
2974 mutex_unlock(&iter->mutex);
2975
2976 iter->trace->wait_pipe(iter);
2977
2978 mutex_lock(&iter->mutex);
2979
2980 if (signal_pending(current))
2981 return -EINTR;
2982
2983 /*
2984 * We block until we read something and tracing is disabled.
2985 * We still block if tracing is disabled, but we have never
2986 * read anything. This allows a user to cat this file, and
2987 * then enable tracing. But after we have read something,
2988 * we give an EOF when tracing is again disabled.
2989 *
2990 * iter->pos will be 0 if we haven't read anything.
2991 */
2992 if (!tracer_enabled && iter->pos)
2993 break;
2994 }
2995
2996 return 1;
2997}
2998
2999/*
3000 * Consumer reader.
3001 */
3002static ssize_t
3003tracing_read_pipe(struct file *filp, char __user *ubuf,
3004 size_t cnt, loff_t *ppos)
3005{
3006 struct trace_iterator *iter = filp->private_data;
3007 static struct tracer *old_tracer;
3008 ssize_t sret;
3009
3010 /* return any leftover data */
3011 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
3012 if (sret != -EBUSY)
3013 return sret;
3014
3015 trace_seq_init(&iter->seq);
3016
3017 /* copy the tracer to avoid using a global lock all around */
3018 mutex_lock(&trace_types_lock);
3019 if (unlikely(old_tracer != current_trace && current_trace)) {
3020 old_tracer = current_trace;
3021 *iter->trace = *current_trace;
3022 }
3023 mutex_unlock(&trace_types_lock);
3024
3025 /*
3026 * Avoid more than one consumer on a single file descriptor
3027 * This is just a matter of traces coherency, the ring buffer itself
3028 * is protected.
3029 */
3030 mutex_lock(&iter->mutex);
3031 if (iter->trace->read) {
3032 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
3033 if (sret)
3034 goto out;
3035 }
3036
3037waitagain:
3038 sret = tracing_wait_pipe(filp);
3039 if (sret <= 0)
3040 goto out;
3041
3042 /* stop when tracing is finished */
3043 if (trace_empty(iter)) {
3044 sret = 0;
3045 goto out;
3046 }
3047
3048 if (cnt >= PAGE_SIZE)
3049 cnt = PAGE_SIZE - 1;
3050
3051 /* reset all but tr, trace, and overruns */
3052 memset(&iter->seq, 0,
3053 sizeof(struct trace_iterator) -
3054 offsetof(struct trace_iterator, seq));
3055 iter->pos = -1;
3056
3057 trace_event_read_lock();
3058 while (find_next_entry_inc(iter) != NULL) {
3059 enum print_line_t ret;
3060 int len = iter->seq.len;
3061
3062 ret = print_trace_line(iter);
3063 if (ret == TRACE_TYPE_PARTIAL_LINE) {
3064 /* don't print partial lines */
3065 iter->seq.len = len;
3066 break;
3067 }
3068 if (ret != TRACE_TYPE_NO_CONSUME)
3069 trace_consume(iter);
3070
3071 if (iter->seq.len >= cnt)
3072 break;
3073 }
3074 trace_event_read_unlock();
3075
3076 /* Now copy what we have to the user */
3077 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
3078 if (iter->seq.readpos >= iter->seq.len)
3079 trace_seq_init(&iter->seq);
3080
3081 /*
3082 * If there was nothing to send to user, inspite of consuming trace
3083 * entries, go back to wait for more entries.
3084 */
3085 if (sret == -EBUSY)
3086 goto waitagain;
3087
3088out:
3089 mutex_unlock(&iter->mutex);
3090
3091 return sret;
3092}
3093
3094static void tracing_pipe_buf_release(struct pipe_inode_info *pipe,
3095 struct pipe_buffer *buf)
3096{
3097 __free_page(buf->page);
3098}
3099
3100static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
3101 unsigned int idx)
3102{
3103 __free_page(spd->pages[idx]);
3104}
3105
3106static struct pipe_buf_operations tracing_pipe_buf_ops = {
3107 .can_merge = 0,
3108 .map = generic_pipe_buf_map,
3109 .unmap = generic_pipe_buf_unmap,
3110 .confirm = generic_pipe_buf_confirm,
3111 .release = tracing_pipe_buf_release,
3112 .steal = generic_pipe_buf_steal,
3113 .get = generic_pipe_buf_get,
3114};
3115
3116static size_t
3117tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
3118{
3119 size_t count;
3120 int ret;
3121
3122 /* Seq buffer is page-sized, exactly what we need. */
3123 for (;;) {
3124 count = iter->seq.len;
3125 ret = print_trace_line(iter);
3126 count = iter->seq.len - count;
3127 if (rem < count) {
3128 rem = 0;
3129 iter->seq.len -= count;
3130 break;
3131 }
3132 if (ret == TRACE_TYPE_PARTIAL_LINE) {
3133 iter->seq.len -= count;
3134 break;
3135 }
3136
3137 if (ret != TRACE_TYPE_NO_CONSUME)
3138 trace_consume(iter);
3139 rem -= count;
3140 if (!find_next_entry_inc(iter)) {
3141 rem = 0;
3142 iter->ent = NULL;
3143 break;
3144 }
3145 }
3146
3147 return rem;
3148}
3149
3150static ssize_t tracing_splice_read_pipe(struct file *filp,
3151 loff_t *ppos,
3152 struct pipe_inode_info *pipe,
3153 size_t len,
3154 unsigned int flags)
3155{
3156 struct page *pages[PIPE_BUFFERS];
3157 struct partial_page partial[PIPE_BUFFERS];
3158 struct trace_iterator *iter = filp->private_data;
3159 struct splice_pipe_desc spd = {
3160 .pages = pages,
3161 .partial = partial,
3162 .nr_pages = 0, /* This gets updated below. */
3163 .flags = flags,
3164 .ops = &tracing_pipe_buf_ops,
3165 .spd_release = tracing_spd_release_pipe,
3166 };
3167 static struct tracer *old_tracer;
3168 ssize_t ret;
3169 size_t rem;
3170 unsigned int i;
3171
3172 /* copy the tracer to avoid using a global lock all around */
3173 mutex_lock(&trace_types_lock);
3174 if (unlikely(old_tracer != current_trace && current_trace)) {
3175 old_tracer = current_trace;
3176 *iter->trace = *current_trace;
3177 }
3178 mutex_unlock(&trace_types_lock);
3179
3180 mutex_lock(&iter->mutex);
3181
3182 if (iter->trace->splice_read) {
3183 ret = iter->trace->splice_read(iter, filp,
3184 ppos, pipe, len, flags);
3185 if (ret)
3186 goto out_err;
3187 }
3188
3189 ret = tracing_wait_pipe(filp);
3190 if (ret <= 0)
3191 goto out_err;
3192
3193 if (!iter->ent && !find_next_entry_inc(iter)) {
3194 ret = -EFAULT;
3195 goto out_err;
3196 }
3197
3198 trace_event_read_lock();
3199
3200 /* Fill as many pages as possible. */
3201 for (i = 0, rem = len; i < PIPE_BUFFERS && rem; i++) {
3202 pages[i] = alloc_page(GFP_KERNEL);
3203 if (!pages[i])
3204 break;
3205
3206 rem = tracing_fill_pipe_page(rem, iter);
3207
3208 /* Copy the data into the page, so we can start over. */
3209 ret = trace_seq_to_buffer(&iter->seq,
3210 page_address(pages[i]),
3211 iter->seq.len);
3212 if (ret < 0) {
3213 __free_page(pages[i]);
3214 break;
3215 }
3216 partial[i].offset = 0;
3217 partial[i].len = iter->seq.len;
3218
3219 trace_seq_init(&iter->seq);
3220 }
3221
3222 trace_event_read_unlock();
3223 mutex_unlock(&iter->mutex);
3224
3225 spd.nr_pages = i;
3226
3227 return splice_to_pipe(pipe, &spd);
3228
3229out_err:
3230 mutex_unlock(&iter->mutex);
3231
3232 return ret;
3233}
3234
3235static ssize_t
3236tracing_entries_read(struct file *filp, char __user *ubuf,
3237 size_t cnt, loff_t *ppos)
3238{
3239 struct trace_array *tr = filp->private_data;
3240 char buf[96];
3241 int r;
3242
3243 mutex_lock(&trace_types_lock);
3244 if (!ring_buffer_expanded)
3245 r = sprintf(buf, "%lu (expanded: %lu)\n",
3246 tr->entries >> 10,
3247 trace_buf_size >> 10);
3248 else
3249 r = sprintf(buf, "%lu\n", tr->entries >> 10);
3250 mutex_unlock(&trace_types_lock);
3251
3252 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3253}
3254
3255static ssize_t
3256tracing_entries_write(struct file *filp, const char __user *ubuf,
3257 size_t cnt, loff_t *ppos)
3258{
3259 unsigned long val;
3260 char buf[64];
3261 int ret, cpu;
3262
3263 if (cnt >= sizeof(buf))
3264 return -EINVAL;
3265
3266 if (copy_from_user(&buf, ubuf, cnt))
3267 return -EFAULT;
3268
3269 buf[cnt] = 0;
3270
3271 ret = strict_strtoul(buf, 10, &val);
3272 if (ret < 0)
3273 return ret;
3274
3275 /* must have at least 1 entry */
3276 if (!val)
3277 return -EINVAL;
3278
3279 mutex_lock(&trace_types_lock);
3280
3281 tracing_stop();
3282
3283 /* disable all cpu buffers */
3284 for_each_tracing_cpu(cpu) {
3285 if (global_trace.data[cpu])
3286 atomic_inc(&global_trace.data[cpu]->disabled);
3287 if (max_tr.data[cpu])
3288 atomic_inc(&max_tr.data[cpu]->disabled);
3289 }
3290
3291 /* value is in KB */
3292 val <<= 10;
3293
3294 if (val != global_trace.entries) {
3295 ret = tracing_resize_ring_buffer(val);
3296 if (ret < 0) {
3297 cnt = ret;
3298 goto out;
3299 }
3300 }
3301
3302 *ppos += cnt;
3303
3304 /* If check pages failed, return ENOMEM */
3305 if (tracing_disabled)
3306 cnt = -ENOMEM;
3307 out:
3308 for_each_tracing_cpu(cpu) {
3309 if (global_trace.data[cpu])
3310 atomic_dec(&global_trace.data[cpu]->disabled);
3311 if (max_tr.data[cpu])
3312 atomic_dec(&max_tr.data[cpu]->disabled);
3313 }
3314
3315 tracing_start();
3316 max_tr.entries = global_trace.entries;
3317 mutex_unlock(&trace_types_lock);
3318
3319 return cnt;
3320}
3321
3322static int mark_printk(const char *fmt, ...)
3323{
3324 int ret;
3325 va_list args;
3326 va_start(args, fmt);
3327 ret = trace_vprintk(0, fmt, args);
3328 va_end(args);
3329 return ret;
3330}
3331
3332static ssize_t
3333tracing_mark_write(struct file *filp, const char __user *ubuf,
3334 size_t cnt, loff_t *fpos)
3335{
3336 char *buf;
3337 char *end;
3338
3339 if (tracing_disabled)
3340 return -EINVAL;
3341
3342 if (cnt > TRACE_BUF_SIZE)
3343 cnt = TRACE_BUF_SIZE;
3344
3345 buf = kmalloc(cnt + 1, GFP_KERNEL);
3346 if (buf == NULL)
3347 return -ENOMEM;
3348
3349 if (copy_from_user(buf, ubuf, cnt)) {
3350 kfree(buf);
3351 return -EFAULT;
3352 }
3353
3354 /* Cut from the first nil or newline. */
3355 buf[cnt] = '\0';
3356 end = strchr(buf, '\n');
3357 if (end)
3358 *end = '\0';
3359
3360 cnt = mark_printk("%s\n", buf);
3361 kfree(buf);
3362 *fpos += cnt;
3363
3364 return cnt;
3365}
3366
3367static ssize_t tracing_clock_read(struct file *filp, char __user *ubuf,
3368 size_t cnt, loff_t *ppos)
3369{
3370 char buf[64];
3371 int bufiter = 0;
3372 int i;
3373
3374 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
3375 bufiter += snprintf(buf + bufiter, sizeof(buf) - bufiter,
3376 "%s%s%s%s", i ? " " : "",
3377 i == trace_clock_id ? "[" : "", trace_clocks[i].name,
3378 i == trace_clock_id ? "]" : "");
3379 bufiter += snprintf(buf + bufiter, sizeof(buf) - bufiter, "\n");
3380
3381 return simple_read_from_buffer(ubuf, cnt, ppos, buf, bufiter);
3382}
3383
3384static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
3385 size_t cnt, loff_t *fpos)
3386{
3387 char buf[64];
3388 const char *clockstr;
3389 int i;
3390
3391 if (cnt >= sizeof(buf))
3392 return -EINVAL;
3393
3394 if (copy_from_user(&buf, ubuf, cnt))
3395 return -EFAULT;
3396
3397 buf[cnt] = 0;
3398
3399 clockstr = strstrip(buf);
3400
3401 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
3402 if (strcmp(trace_clocks[i].name, clockstr) == 0)
3403 break;
3404 }
3405 if (i == ARRAY_SIZE(trace_clocks))
3406 return -EINVAL;
3407
3408 trace_clock_id = i;
3409
3410 mutex_lock(&trace_types_lock);
3411
3412 ring_buffer_set_clock(global_trace.buffer, trace_clocks[i].func);
3413 if (max_tr.buffer)
3414 ring_buffer_set_clock(max_tr.buffer, trace_clocks[i].func);
3415
3416 mutex_unlock(&trace_types_lock);
3417
3418 *fpos += cnt;
3419
3420 return cnt;
3421}
3422
3423static const struct file_operations tracing_max_lat_fops = {
3424 .open = tracing_open_generic,
3425 .read = tracing_max_lat_read,
3426 .write = tracing_max_lat_write,
3427};
3428
3429static const struct file_operations tracing_ctrl_fops = {
3430 .open = tracing_open_generic,
3431 .read = tracing_ctrl_read,
3432 .write = tracing_ctrl_write,
3433};
3434
3435static const struct file_operations set_tracer_fops = {
3436 .open = tracing_open_generic,
3437 .read = tracing_set_trace_read,
3438 .write = tracing_set_trace_write,
3439};
3440
3441static const struct file_operations tracing_pipe_fops = {
3442 .open = tracing_open_pipe,
3443 .poll = tracing_poll_pipe,
3444 .read = tracing_read_pipe,
3445 .splice_read = tracing_splice_read_pipe,
3446 .release = tracing_release_pipe,
3447};
3448
3449static const struct file_operations tracing_entries_fops = {
3450 .open = tracing_open_generic,
3451 .read = tracing_entries_read,
3452 .write = tracing_entries_write,
3453};
3454
3455static const struct file_operations tracing_mark_fops = {
3456 .open = tracing_open_generic,
3457 .write = tracing_mark_write,
3458};
3459
3460static const struct file_operations trace_clock_fops = {
3461 .open = tracing_open_generic,
3462 .read = tracing_clock_read,
3463 .write = tracing_clock_write,
3464};
3465
3466struct ftrace_buffer_info {
3467 struct trace_array *tr;
3468 void *spare;
3469 int cpu;
3470 unsigned int read;
3471};
3472
3473static int tracing_buffers_open(struct inode *inode, struct file *filp)
3474{
3475 int cpu = (int)(long)inode->i_private;
3476 struct ftrace_buffer_info *info;
3477
3478 if (tracing_disabled)
3479 return -ENODEV;
3480
3481 info = kzalloc(sizeof(*info), GFP_KERNEL);
3482 if (!info)
3483 return -ENOMEM;
3484
3485 info->tr = &global_trace;
3486 info->cpu = cpu;
3487 info->spare = NULL;
3488 /* Force reading ring buffer for first read */
3489 info->read = (unsigned int)-1;
3490
3491 filp->private_data = info;
3492
3493 return nonseekable_open(inode, filp);
3494}
3495
3496static ssize_t
3497tracing_buffers_read(struct file *filp, char __user *ubuf,
3498 size_t count, loff_t *ppos)
3499{
3500 struct ftrace_buffer_info *info = filp->private_data;
3501 unsigned int pos;
3502 ssize_t ret;
3503 size_t size;
3504
3505 if (!count)
3506 return 0;
3507
3508 if (!info->spare)
3509 info->spare = ring_buffer_alloc_read_page(info->tr->buffer);
3510 if (!info->spare)
3511 return -ENOMEM;
3512
3513 /* Do we have previous read data to read? */
3514 if (info->read < PAGE_SIZE)
3515 goto read;
3516
3517 info->read = 0;
3518
3519 ret = ring_buffer_read_page(info->tr->buffer,
3520 &info->spare,
3521 count,
3522 info->cpu, 0);
3523 if (ret < 0)
3524 return 0;
3525
3526 pos = ring_buffer_page_len(info->spare);
3527
3528 if (pos < PAGE_SIZE)
3529 memset(info->spare + pos, 0, PAGE_SIZE - pos);
3530
3531read:
3532 size = PAGE_SIZE - info->read;
3533 if (size > count)
3534 size = count;
3535
3536 ret = copy_to_user(ubuf, info->spare + info->read, size);
3537 if (ret == size)
3538 return -EFAULT;
3539 size -= ret;
3540
3541 *ppos += size;
3542 info->read += size;
3543
3544 return size;
3545}
3546
3547static int tracing_buffers_release(struct inode *inode, struct file *file)
3548{
3549 struct ftrace_buffer_info *info = file->private_data;
3550
3551 if (info->spare)
3552 ring_buffer_free_read_page(info->tr->buffer, info->spare);
3553 kfree(info);
3554
3555 return 0;
3556}
3557
3558struct buffer_ref {
3559 struct ring_buffer *buffer;
3560 void *page;
3561 int ref;
3562};
3563
3564static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
3565 struct pipe_buffer *buf)
3566{
3567 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
3568
3569 if (--ref->ref)
3570 return;
3571
3572 ring_buffer_free_read_page(ref->buffer, ref->page);
3573 kfree(ref);
3574 buf->private = 0;
3575}
3576
3577static int buffer_pipe_buf_steal(struct pipe_inode_info *pipe,
3578 struct pipe_buffer *buf)
3579{
3580 return 1;
3581}
3582
3583static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
3584 struct pipe_buffer *buf)
3585{
3586 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
3587
3588 ref->ref++;
3589}
3590
3591/* Pipe buffer operations for a buffer. */
3592static struct pipe_buf_operations buffer_pipe_buf_ops = {
3593 .can_merge = 0,
3594 .map = generic_pipe_buf_map,
3595 .unmap = generic_pipe_buf_unmap,
3596 .confirm = generic_pipe_buf_confirm,
3597 .release = buffer_pipe_buf_release,
3598 .steal = buffer_pipe_buf_steal,
3599 .get = buffer_pipe_buf_get,
3600};
3601
3602/*
3603 * Callback from splice_to_pipe(), if we need to release some pages
3604 * at the end of the spd in case we error'ed out in filling the pipe.
3605 */
3606static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
3607{
3608 struct buffer_ref *ref =
3609 (struct buffer_ref *)spd->partial[i].private;
3610
3611 if (--ref->ref)
3612 return;
3613
3614 ring_buffer_free_read_page(ref->buffer, ref->page);
3615 kfree(ref);
3616 spd->partial[i].private = 0;
3617}
3618
3619static ssize_t
3620tracing_buffers_splice_read(struct file *file, loff_t *ppos,
3621 struct pipe_inode_info *pipe, size_t len,
3622 unsigned int flags)
3623{
3624 struct ftrace_buffer_info *info = file->private_data;
3625 struct partial_page partial[PIPE_BUFFERS];
3626 struct page *pages[PIPE_BUFFERS];
3627 struct splice_pipe_desc spd = {
3628 .pages = pages,
3629 .partial = partial,
3630 .flags = flags,
3631 .ops = &buffer_pipe_buf_ops,
3632 .spd_release = buffer_spd_release,
3633 };
3634 struct buffer_ref *ref;
3635 int entries, size, i;
3636 size_t ret;
3637
3638 if (*ppos & (PAGE_SIZE - 1)) {
3639 WARN_ONCE(1, "Ftrace: previous read must page-align\n");
3640 return -EINVAL;
3641 }
3642
3643 if (len & (PAGE_SIZE - 1)) {
3644 WARN_ONCE(1, "Ftrace: splice_read should page-align\n");
3645 if (len < PAGE_SIZE)
3646 return -EINVAL;
3647 len &= PAGE_MASK;
3648 }
3649
3650 entries = ring_buffer_entries_cpu(info->tr->buffer, info->cpu);
3651
3652 for (i = 0; i < PIPE_BUFFERS && len && entries; i++, len -= PAGE_SIZE) {
3653 struct page *page;
3654 int r;
3655
3656 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
3657 if (!ref)
3658 break;
3659
3660 ref->ref = 1;
3661 ref->buffer = info->tr->buffer;
3662 ref->page = ring_buffer_alloc_read_page(ref->buffer);
3663 if (!ref->page) {
3664 kfree(ref);
3665 break;
3666 }
3667
3668 r = ring_buffer_read_page(ref->buffer, &ref->page,
3669 len, info->cpu, 1);
3670 if (r < 0) {
3671 ring_buffer_free_read_page(ref->buffer,
3672 ref->page);
3673 kfree(ref);
3674 break;
3675 }
3676
3677 /*
3678 * zero out any left over data, this is going to
3679 * user land.
3680 */
3681 size = ring_buffer_page_len(ref->page);
3682 if (size < PAGE_SIZE)
3683 memset(ref->page + size, 0, PAGE_SIZE - size);
3684
3685 page = virt_to_page(ref->page);
3686
3687 spd.pages[i] = page;
3688 spd.partial[i].len = PAGE_SIZE;
3689 spd.partial[i].offset = 0;
3690 spd.partial[i].private = (unsigned long)ref;
3691 spd.nr_pages++;
3692 *ppos += PAGE_SIZE;
3693
3694 entries = ring_buffer_entries_cpu(info->tr->buffer, info->cpu);
3695 }
3696
3697 spd.nr_pages = i;
3698
3699 /* did we read anything? */
3700 if (!spd.nr_pages) {
3701 if (flags & SPLICE_F_NONBLOCK)
3702 ret = -EAGAIN;
3703 else
3704 ret = 0;
3705 /* TODO: block */
3706 return ret;
3707 }
3708
3709 ret = splice_to_pipe(pipe, &spd);
3710
3711 return ret;
3712}
3713
3714static const struct file_operations tracing_buffers_fops = {
3715 .open = tracing_buffers_open,
3716 .read = tracing_buffers_read,
3717 .release = tracing_buffers_release,
3718 .splice_read = tracing_buffers_splice_read,
3719 .llseek = no_llseek,
3720};
3721
3722static ssize_t
3723tracing_stats_read(struct file *filp, char __user *ubuf,
3724 size_t count, loff_t *ppos)
3725{
3726 unsigned long cpu = (unsigned long)filp->private_data;
3727 struct trace_array *tr = &global_trace;
3728 struct trace_seq *s;
3729 unsigned long cnt;
3730
3731 s = kmalloc(sizeof(*s), GFP_KERNEL);
3732 if (!s)
3733 return ENOMEM;
3734
3735 trace_seq_init(s);
3736
3737 cnt = ring_buffer_entries_cpu(tr->buffer, cpu);
3738 trace_seq_printf(s, "entries: %ld\n", cnt);
3739
3740 cnt = ring_buffer_overrun_cpu(tr->buffer, cpu);
3741 trace_seq_printf(s, "overrun: %ld\n", cnt);
3742
3743 cnt = ring_buffer_commit_overrun_cpu(tr->buffer, cpu);
3744 trace_seq_printf(s, "commit overrun: %ld\n", cnt);
3745
3746 count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->len);
3747
3748 kfree(s);
3749
3750 return count;
3751}
3752
3753static const struct file_operations tracing_stats_fops = {
3754 .open = tracing_open_generic,
3755 .read = tracing_stats_read,
3756};
3757
3758#ifdef CONFIG_DYNAMIC_FTRACE
3759
3760int __weak ftrace_arch_read_dyn_info(char *buf, int size)
3761{
3762 return 0;
3763}
3764
3765static ssize_t
3766tracing_read_dyn_info(struct file *filp, char __user *ubuf,
3767 size_t cnt, loff_t *ppos)
3768{
3769 static char ftrace_dyn_info_buffer[1024];
3770 static DEFINE_MUTEX(dyn_info_mutex);
3771 unsigned long *p = filp->private_data;
3772 char *buf = ftrace_dyn_info_buffer;
3773 int size = ARRAY_SIZE(ftrace_dyn_info_buffer);
3774 int r;
3775
3776 mutex_lock(&dyn_info_mutex);
3777 r = sprintf(buf, "%ld ", *p);
3778
3779 r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r);
3780 buf[r++] = '\n';
3781
3782 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3783
3784 mutex_unlock(&dyn_info_mutex);
3785
3786 return r;
3787}
3788
3789static const struct file_operations tracing_dyn_info_fops = {
3790 .open = tracing_open_generic,
3791 .read = tracing_read_dyn_info,
3792};
3793#endif
3794
3795static struct dentry *d_tracer;
3796
3797struct dentry *tracing_init_dentry(void)
3798{
3799 static int once;
3800
3801 if (d_tracer)
3802 return d_tracer;
3803
3804 if (!debugfs_initialized())
3805 return NULL;
3806
3807 d_tracer = debugfs_create_dir("tracing", NULL);
3808
3809 if (!d_tracer && !once) {
3810 once = 1;
3811 pr_warning("Could not create debugfs directory 'tracing'\n");
3812 return NULL;
3813 }
3814
3815 return d_tracer;
3816}
3817
3818static struct dentry *d_percpu;
3819
3820struct dentry *tracing_dentry_percpu(void)
3821{
3822 static int once;
3823 struct dentry *d_tracer;
3824
3825 if (d_percpu)
3826 return d_percpu;
3827
3828 d_tracer = tracing_init_dentry();
3829
3830 if (!d_tracer)
3831 return NULL;
3832
3833 d_percpu = debugfs_create_dir("per_cpu", d_tracer);
3834
3835 if (!d_percpu && !once) {
3836 once = 1;
3837 pr_warning("Could not create debugfs directory 'per_cpu'\n");
3838 return NULL;
3839 }
3840
3841 return d_percpu;
3842}
3843
3844static void tracing_init_debugfs_percpu(long cpu)
3845{
3846 struct dentry *d_percpu = tracing_dentry_percpu();
3847 struct dentry *d_cpu;
3848 /* strlen(cpu) + MAX(log10(cpu)) + '\0' */
3849 char cpu_dir[7];
3850
3851 if (cpu > 999 || cpu < 0)
3852 return;
3853
3854 sprintf(cpu_dir, "cpu%ld", cpu);
3855 d_cpu = debugfs_create_dir(cpu_dir, d_percpu);
3856 if (!d_cpu) {
3857 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir);
3858 return;
3859 }
3860
3861 /* per cpu trace_pipe */
3862 trace_create_file("trace_pipe", 0444, d_cpu,
3863 (void *) cpu, &tracing_pipe_fops);
3864
3865 /* per cpu trace */
3866 trace_create_file("trace", 0644, d_cpu,
3867 (void *) cpu, &tracing_fops);
3868
3869 trace_create_file("trace_pipe_raw", 0444, d_cpu,
3870 (void *) cpu, &tracing_buffers_fops);
3871
3872 trace_create_file("stats", 0444, d_cpu,
3873 (void *) cpu, &tracing_stats_fops);
3874}
3875
3876#ifdef CONFIG_FTRACE_SELFTEST
3877/* Let selftest have access to static functions in this file */
3878#include "trace_selftest.c"
3879#endif
3880
3881struct trace_option_dentry {
3882 struct tracer_opt *opt;
3883 struct tracer_flags *flags;
3884 struct dentry *entry;
3885};
3886
3887static ssize_t
3888trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
3889 loff_t *ppos)
3890{
3891 struct trace_option_dentry *topt = filp->private_data;
3892 char *buf;
3893
3894 if (topt->flags->val & topt->opt->bit)
3895 buf = "1\n";
3896 else
3897 buf = "0\n";
3898
3899 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
3900}
3901
3902static ssize_t
3903trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
3904 loff_t *ppos)
3905{
3906 struct trace_option_dentry *topt = filp->private_data;
3907 unsigned long val;
3908 char buf[64];
3909 int ret;
3910
3911 if (cnt >= sizeof(buf))
3912 return -EINVAL;
3913
3914 if (copy_from_user(&buf, ubuf, cnt))
3915 return -EFAULT;
3916
3917 buf[cnt] = 0;
3918
3919 ret = strict_strtoul(buf, 10, &val);
3920 if (ret < 0)
3921 return ret;
3922
3923 ret = 0;
3924 switch (val) {
3925 case 0:
3926 /* do nothing if already cleared */
3927 if (!(topt->flags->val & topt->opt->bit))
3928 break;
3929
3930 mutex_lock(&trace_types_lock);
3931 if (current_trace->set_flag)
3932 ret = current_trace->set_flag(topt->flags->val,
3933 topt->opt->bit, 0);
3934 mutex_unlock(&trace_types_lock);
3935 if (ret)
3936 return ret;
3937 topt->flags->val &= ~topt->opt->bit;
3938 break;
3939 case 1:
3940 /* do nothing if already set */
3941 if (topt->flags->val & topt->opt->bit)
3942 break;
3943
3944 mutex_lock(&trace_types_lock);
3945 if (current_trace->set_flag)
3946 ret = current_trace->set_flag(topt->flags->val,
3947 topt->opt->bit, 1);
3948 mutex_unlock(&trace_types_lock);
3949 if (ret)
3950 return ret;
3951 topt->flags->val |= topt->opt->bit;
3952 break;
3953
3954 default:
3955 return -EINVAL;
3956 }
3957
3958 *ppos += cnt;
3959
3960 return cnt;
3961}
3962
3963
3964static const struct file_operations trace_options_fops = {
3965 .open = tracing_open_generic,
3966 .read = trace_options_read,
3967 .write = trace_options_write,
3968};
3969
3970static ssize_t
3971trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
3972 loff_t *ppos)
3973{
3974 long index = (long)filp->private_data;
3975 char *buf;
3976
3977 if (trace_flags & (1 << index))
3978 buf = "1\n";
3979 else
3980 buf = "0\n";
3981
3982 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
3983}
3984
3985static ssize_t
3986trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
3987 loff_t *ppos)
3988{
3989 long index = (long)filp->private_data;
3990 char buf[64];
3991 unsigned long val;
3992 int ret;
3993
3994 if (cnt >= sizeof(buf))
3995 return -EINVAL;
3996
3997 if (copy_from_user(&buf, ubuf, cnt))
3998 return -EFAULT;
3999
4000 buf[cnt] = 0;
4001
4002 ret = strict_strtoul(buf, 10, &val);
4003 if (ret < 0)
4004 return ret;
4005
4006 if (val != 0 && val != 1)
4007 return -EINVAL;
4008 set_tracer_flags(1 << index, val);
4009
4010 *ppos += cnt;
4011
4012 return cnt;
4013}
4014
4015static const struct file_operations trace_options_core_fops = {
4016 .open = tracing_open_generic,
4017 .read = trace_options_core_read,
4018 .write = trace_options_core_write,
4019};
4020
4021struct dentry *trace_create_file(const char *name,
4022 mode_t mode,
4023 struct dentry *parent,
4024 void *data,
4025 const struct file_operations *fops)
4026{
4027 struct dentry *ret;
4028
4029 ret = debugfs_create_file(name, mode, parent, data, fops);
4030 if (!ret)
4031 pr_warning("Could not create debugfs '%s' entry\n", name);
4032
4033 return ret;
4034}
4035
4036
4037static struct dentry *trace_options_init_dentry(void)
4038{
4039 struct dentry *d_tracer;
4040 static struct dentry *t_options;
4041
4042 if (t_options)
4043 return t_options;
4044
4045 d_tracer = tracing_init_dentry();
4046 if (!d_tracer)
4047 return NULL;
4048
4049 t_options = debugfs_create_dir("options", d_tracer);
4050 if (!t_options) {
4051 pr_warning("Could not create debugfs directory 'options'\n");
4052 return NULL;
4053 }
4054
4055 return t_options;
4056}
4057
4058static void
4059create_trace_option_file(struct trace_option_dentry *topt,
4060 struct tracer_flags *flags,
4061 struct tracer_opt *opt)
4062{
4063 struct dentry *t_options;
4064
4065 t_options = trace_options_init_dentry();
4066 if (!t_options)
4067 return;
4068
4069 topt->flags = flags;
4070 topt->opt = opt;
4071
4072 topt->entry = trace_create_file(opt->name, 0644, t_options, topt,
4073 &trace_options_fops);
4074
4075}
4076
4077static struct trace_option_dentry *
4078create_trace_option_files(struct tracer *tracer)
4079{
4080 struct trace_option_dentry *topts;
4081 struct tracer_flags *flags;
4082 struct tracer_opt *opts;
4083 int cnt;
4084
4085 if (!tracer)
4086 return NULL;
4087
4088 flags = tracer->flags;
4089
4090 if (!flags || !flags->opts)
4091 return NULL;
4092
4093 opts = flags->opts;
4094
4095 for (cnt = 0; opts[cnt].name; cnt++)
4096 ;
4097
4098 topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
4099 if (!topts)
4100 return NULL;
4101
4102 for (cnt = 0; opts[cnt].name; cnt++)
4103 create_trace_option_file(&topts[cnt], flags,
4104 &opts[cnt]);
4105
4106 return topts;
4107}
4108
4109static void
4110destroy_trace_option_files(struct trace_option_dentry *topts)
4111{
4112 int cnt;
4113
4114 if (!topts)
4115 return;
4116
4117 for (cnt = 0; topts[cnt].opt; cnt++) {
4118 if (topts[cnt].entry)
4119 debugfs_remove(topts[cnt].entry);
4120 }
4121
4122 kfree(topts);
4123}
4124
4125static struct dentry *
4126create_trace_option_core_file(const char *option, long index)
4127{
4128 struct dentry *t_options;
4129
4130 t_options = trace_options_init_dentry();
4131 if (!t_options)
4132 return NULL;
4133
4134 return trace_create_file(option, 0644, t_options, (void *)index,
4135 &trace_options_core_fops);
4136}
4137
4138static __init void create_trace_options_dir(void)
4139{
4140 struct dentry *t_options;
4141 int i;
4142
4143 t_options = trace_options_init_dentry();
4144 if (!t_options)
4145 return;
4146
4147 for (i = 0; trace_options[i]; i++)
4148 create_trace_option_core_file(trace_options[i], i);
4149}
4150
4151static __init int tracer_init_debugfs(void)
4152{
4153 struct dentry *d_tracer;
4154 int cpu;
4155
4156 d_tracer = tracing_init_dentry();
4157
4158 trace_create_file("tracing_enabled", 0644, d_tracer,
4159 &global_trace, &tracing_ctrl_fops);
4160
4161 trace_create_file("trace_options", 0644, d_tracer,
4162 NULL, &tracing_iter_fops);
4163
4164 trace_create_file("tracing_cpumask", 0644, d_tracer,
4165 NULL, &tracing_cpumask_fops);
4166
4167 trace_create_file("trace", 0644, d_tracer,
4168 (void *) TRACE_PIPE_ALL_CPU, &tracing_fops);
4169
4170 trace_create_file("available_tracers", 0444, d_tracer,
4171 &global_trace, &show_traces_fops);
4172
4173 trace_create_file("current_tracer", 0644, d_tracer,
4174 &global_trace, &set_tracer_fops);
4175
4176#ifdef CONFIG_TRACER_MAX_TRACE
4177 trace_create_file("tracing_max_latency", 0644, d_tracer,
4178 &tracing_max_latency, &tracing_max_lat_fops);
4179
4180 trace_create_file("tracing_thresh", 0644, d_tracer,
4181 &tracing_thresh, &tracing_max_lat_fops);
4182#endif
4183
4184 trace_create_file("README", 0444, d_tracer,
4185 NULL, &tracing_readme_fops);
4186
4187 trace_create_file("trace_pipe", 0444, d_tracer,
4188 (void *) TRACE_PIPE_ALL_CPU, &tracing_pipe_fops);
4189
4190 trace_create_file("buffer_size_kb", 0644, d_tracer,
4191 &global_trace, &tracing_entries_fops);
4192
4193 trace_create_file("trace_marker", 0220, d_tracer,
4194 NULL, &tracing_mark_fops);
4195
4196 trace_create_file("saved_cmdlines", 0444, d_tracer,
4197 NULL, &tracing_saved_cmdlines_fops);
4198
4199 trace_create_file("trace_clock", 0644, d_tracer, NULL,
4200 &trace_clock_fops);
4201
4202#ifdef CONFIG_DYNAMIC_FTRACE
4203 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
4204 &ftrace_update_tot_cnt, &tracing_dyn_info_fops);
4205#endif
4206#ifdef CONFIG_SYSPROF_TRACER
4207 init_tracer_sysprof_debugfs(d_tracer);
4208#endif
4209
4210 create_trace_options_dir();
4211
4212 for_each_tracing_cpu(cpu)
4213 tracing_init_debugfs_percpu(cpu);
4214
4215 return 0;
4216}
4217
4218static int trace_panic_handler(struct notifier_block *this,
4219 unsigned long event, void *unused)
4220{
4221 if (ftrace_dump_on_oops)
4222 ftrace_dump();
4223 return NOTIFY_OK;
4224}
4225
4226static struct notifier_block trace_panic_notifier = {
4227 .notifier_call = trace_panic_handler,
4228 .next = NULL,
4229 .priority = 150 /* priority: INT_MAX >= x >= 0 */
4230};
4231
4232static int trace_die_handler(struct notifier_block *self,
4233 unsigned long val,
4234 void *data)
4235{
4236 switch (val) {
4237 case DIE_OOPS:
4238 if (ftrace_dump_on_oops)
4239 ftrace_dump();
4240 break;
4241 default:
4242 break;
4243 }
4244 return NOTIFY_OK;
4245}
4246
4247static struct notifier_block trace_die_notifier = {
4248 .notifier_call = trace_die_handler,
4249 .priority = 200
4250};
4251
4252/*
4253 * printk is set to max of 1024, we really don't need it that big.
4254 * Nothing should be printing 1000 characters anyway.
4255 */
4256#define TRACE_MAX_PRINT 1000
4257
4258/*
4259 * Define here KERN_TRACE so that we have one place to modify
4260 * it if we decide to change what log level the ftrace dump
4261 * should be at.
4262 */
4263#define KERN_TRACE KERN_EMERG
4264
4265static void
4266trace_printk_seq(struct trace_seq *s)
4267{
4268 /* Probably should print a warning here. */
4269 if (s->len >= 1000)
4270 s->len = 1000;
4271
4272 /* should be zero ended, but we are paranoid. */
4273 s->buffer[s->len] = 0;
4274
4275 printk(KERN_TRACE "%s", s->buffer);
4276
4277 trace_seq_init(s);
4278}
4279
4280static void __ftrace_dump(bool disable_tracing)
4281{
4282 static raw_spinlock_t ftrace_dump_lock =
4283 (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
4284 /* use static because iter can be a bit big for the stack */
4285 static struct trace_iterator iter;
4286 unsigned int old_userobj;
4287 static int dump_ran;
4288 unsigned long flags;
4289 int cnt = 0, cpu;
4290
4291 /* only one dump */
4292 local_irq_save(flags);
4293 __raw_spin_lock(&ftrace_dump_lock);
4294 if (dump_ran)
4295 goto out;
4296
4297 dump_ran = 1;
4298
4299 tracing_off();
4300
4301 if (disable_tracing)
4302 ftrace_kill();
4303
4304 for_each_tracing_cpu(cpu) {
4305 atomic_inc(&global_trace.data[cpu]->disabled);
4306 }
4307
4308 old_userobj = trace_flags & TRACE_ITER_SYM_USEROBJ;
4309
4310 /* don't look at user memory in panic mode */
4311 trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
4312
4313 printk(KERN_TRACE "Dumping ftrace buffer:\n");
4314
4315 /* Simulate the iterator */
4316 iter.tr = &global_trace;
4317 iter.trace = current_trace;
4318 iter.cpu_file = TRACE_PIPE_ALL_CPU;
4319
4320 /*
4321 * We need to stop all tracing on all CPUS to read the
4322 * the next buffer. This is a bit expensive, but is
4323 * not done often. We fill all what we can read,
4324 * and then release the locks again.
4325 */
4326
4327 while (!trace_empty(&iter)) {
4328
4329 if (!cnt)
4330 printk(KERN_TRACE "---------------------------------\n");
4331
4332 cnt++;
4333
4334 /* reset all but tr, trace, and overruns */
4335 memset(&iter.seq, 0,
4336 sizeof(struct trace_iterator) -
4337 offsetof(struct trace_iterator, seq));
4338 iter.iter_flags |= TRACE_FILE_LAT_FMT;
4339 iter.pos = -1;
4340
4341 if (find_next_entry_inc(&iter) != NULL) {
4342 int ret;
4343
4344 ret = print_trace_line(&iter);
4345 if (ret != TRACE_TYPE_NO_CONSUME)
4346 trace_consume(&iter);
4347 }
4348
4349 trace_printk_seq(&iter.seq);
4350 }
4351
4352 if (!cnt)
4353 printk(KERN_TRACE " (ftrace buffer empty)\n");
4354 else
4355 printk(KERN_TRACE "---------------------------------\n");
4356
4357 /* Re-enable tracing if requested */
4358 if (!disable_tracing) {
4359 trace_flags |= old_userobj;
4360
4361 for_each_tracing_cpu(cpu) {
4362 atomic_dec(&global_trace.data[cpu]->disabled);
4363 }
4364 tracing_on();
4365 }
4366
4367 out:
4368 __raw_spin_unlock(&ftrace_dump_lock);
4369 local_irq_restore(flags);
4370}
4371
4372/* By default: disable tracing after the dump */
4373void ftrace_dump(void)
4374{
4375 __ftrace_dump(true);
4376}
4377
4378__init static int tracer_alloc_buffers(void)
4379{
4380 int ring_buf_size;
4381 int i;
4382 int ret = -ENOMEM;
4383
4384 if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
4385 goto out;
4386
4387 if (!alloc_cpumask_var(&tracing_cpumask, GFP_KERNEL))
4388 goto out_free_buffer_mask;
4389
4390 if (!zalloc_cpumask_var(&tracing_reader_cpumask, GFP_KERNEL))
4391 goto out_free_tracing_cpumask;
4392
4393 /* To save memory, keep the ring buffer size to its minimum */
4394 if (ring_buffer_expanded)
4395 ring_buf_size = trace_buf_size;
4396 else
4397 ring_buf_size = 1;
4398
4399 cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
4400 cpumask_copy(tracing_cpumask, cpu_all_mask);
4401
4402 /* TODO: make the number of buffers hot pluggable with CPUS */
4403 global_trace.buffer = ring_buffer_alloc(ring_buf_size,
4404 TRACE_BUFFER_FLAGS);
4405 if (!global_trace.buffer) {
4406 printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
4407 WARN_ON(1);
4408 goto out_free_cpumask;
4409 }
4410 global_trace.entries = ring_buffer_size(global_trace.buffer);
4411
4412
4413#ifdef CONFIG_TRACER_MAX_TRACE
4414 max_tr.buffer = ring_buffer_alloc(ring_buf_size,
4415 TRACE_BUFFER_FLAGS);
4416 if (!max_tr.buffer) {
4417 printk(KERN_ERR "tracer: failed to allocate max ring buffer!\n");
4418 WARN_ON(1);
4419 ring_buffer_free(global_trace.buffer);
4420 goto out_free_cpumask;
4421 }
4422 max_tr.entries = ring_buffer_size(max_tr.buffer);
4423 WARN_ON(max_tr.entries != global_trace.entries);
4424#endif
4425
4426 /* Allocate the first page for all buffers */
4427 for_each_tracing_cpu(i) {
4428 global_trace.data[i] = &per_cpu(global_trace_cpu, i);
4429 max_tr.data[i] = &per_cpu(max_data, i);
4430 }
4431
4432 trace_init_cmdlines();
4433
4434 register_tracer(&nop_trace);
4435 current_trace = &nop_trace;
4436#ifdef CONFIG_BOOT_TRACER
4437 register_tracer(&boot_tracer);
4438#endif
4439 /* All seems OK, enable tracing */
4440 tracing_disabled = 0;
4441
4442 atomic_notifier_chain_register(&panic_notifier_list,
4443 &trace_panic_notifier);
4444
4445 register_die_notifier(&trace_die_notifier);
4446
4447 return 0;
4448
4449out_free_cpumask:
4450 free_cpumask_var(tracing_reader_cpumask);
4451out_free_tracing_cpumask:
4452 free_cpumask_var(tracing_cpumask);
4453out_free_buffer_mask:
4454 free_cpumask_var(tracing_buffer_mask);
4455out:
4456 return ret;
4457}
4458
4459__init static int clear_boot_tracer(void)
4460{
4461 /*
4462 * The default tracer at boot buffer is an init section.
4463 * This function is called in lateinit. If we did not
4464 * find the boot tracer, then clear it out, to prevent
4465 * later registration from accessing the buffer that is
4466 * about to be freed.
4467 */
4468 if (!default_bootup_tracer)
4469 return 0;
4470
4471 printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
4472 default_bootup_tracer);
4473 default_bootup_tracer = NULL;
4474
4475 return 0;
4476}
4477
4478early_initcall(tracer_alloc_buffers);
4479fs_initcall(tracer_init_debugfs);
4480late_initcall(clear_boot_tracer);