2 * ring buffer based function tracer
4 * Copyright (C) 2007-2012 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
7 * Originally taken from the RT patch by:
8 * Arnaldo Carvalho de Melo <acme@redhat.com>
10 * Based on code from the latency_tracer, that is:
11 * Copyright (C) 2004-2006 Ingo Molnar
12 * Copyright (C) 2004 Nadia Yvette Chambers
14 #include <linux/ring_buffer.h>
15 #include <generated/utsrelease.h>
16 #include <linux/stacktrace.h>
17 #include <linux/writeback.h>
18 #include <linux/kallsyms.h>
19 #include <linux/seq_file.h>
20 #include <linux/notifier.h>
21 #include <linux/irqflags.h>
22 #include <linux/debugfs.h>
23 #include <linux/pagemap.h>
24 #include <linux/hardirq.h>
25 #include <linux/linkage.h>
26 #include <linux/uaccess.h>
27 #include <linux/kprobes.h>
28 #include <linux/ftrace.h>
29 #include <linux/module.h>
30 #include <linux/percpu.h>
31 #include <linux/splice.h>
32 #include <linux/kdebug.h>
33 #include <linux/string.h>
34 #include <linux/rwsem.h>
35 #include <linux/slab.h>
36 #include <linux/ctype.h>
37 #include <linux/init.h>
38 #include <linux/poll.h>
39 #include <linux/nmi.h>
41 #include <linux/sched/rt.h>
44 #include "trace_output.h"
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.
50 bool ring_buffer_expanded
;
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.
59 static bool __read_mostly tracing_selftest_running
;
62 * If a tracer is running, we do not want to run SELFTEST.
64 bool __read_mostly tracing_selftest_disabled
;
66 /* For tracers that don't implement custom flags */
67 static struct tracer_opt dummy_tracer_opt
[] = {
71 static struct tracer_flags dummy_tracer_flags
= {
73 .opts
= dummy_tracer_opt
76 static int dummy_set_flag(u32 old_flags
, u32 bit
, int set
)
82 * To prevent the comm cache from being overwritten when no
83 * tracing is active, only save the comm when a trace event
86 static DEFINE_PER_CPU(bool, trace_cmdline_save
);
89 * Kill all tracing for good (never come back).
90 * It is initialized to 1 but will turn to zero if the initialization
91 * of the tracer is successful. But that is the only place that sets
94 static int tracing_disabled
= 1;
96 DEFINE_PER_CPU(int, ftrace_cpu_disabled
);
98 cpumask_var_t __read_mostly tracing_buffer_mask
;
101 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
103 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
104 * is set, then ftrace_dump is called. This will output the contents
105 * of the ftrace buffers to the console. This is very useful for
106 * capturing traces that lead to crashes and outputing it to a
109 * It is default off, but you can enable it with either specifying
110 * "ftrace_dump_on_oops" in the kernel command line, or setting
111 * /proc/sys/kernel/ftrace_dump_on_oops
112 * Set 1 if you want to dump buffers of all CPUs
113 * Set 2 if you want to dump the buffer of the CPU that triggered oops
116 enum ftrace_dump_mode ftrace_dump_on_oops
;
118 /* When set, tracing will stop when a WARN*() is hit */
119 int __disable_trace_on_warning
;
121 static int tracing_set_tracer(const char *buf
);
123 #define MAX_TRACER_SIZE 100
124 static char bootup_tracer_buf
[MAX_TRACER_SIZE
] __initdata
;
125 static char *default_bootup_tracer
;
127 static bool allocate_snapshot
;
129 static int __init
set_cmdline_ftrace(char *str
)
131 strlcpy(bootup_tracer_buf
, str
, MAX_TRACER_SIZE
);
132 default_bootup_tracer
= bootup_tracer_buf
;
133 /* We are using ftrace early, expand it */
134 ring_buffer_expanded
= true;
137 __setup("ftrace=", set_cmdline_ftrace
);
139 static int __init
set_ftrace_dump_on_oops(char *str
)
141 if (*str
++ != '=' || !*str
) {
142 ftrace_dump_on_oops
= DUMP_ALL
;
146 if (!strcmp("orig_cpu", str
)) {
147 ftrace_dump_on_oops
= DUMP_ORIG
;
153 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops
);
155 static int __init
stop_trace_on_warning(char *str
)
157 __disable_trace_on_warning
= 1;
160 __setup("traceoff_on_warning=", stop_trace_on_warning
);
162 static int __init
boot_alloc_snapshot(char *str
)
164 allocate_snapshot
= true;
165 /* We also need the main ring buffer expanded */
166 ring_buffer_expanded
= true;
169 __setup("alloc_snapshot", boot_alloc_snapshot
);
172 static char trace_boot_options_buf
[MAX_TRACER_SIZE
] __initdata
;
173 static char *trace_boot_options __initdata
;
175 static int __init
set_trace_boot_options(char *str
)
177 strlcpy(trace_boot_options_buf
, str
, MAX_TRACER_SIZE
);
178 trace_boot_options
= trace_boot_options_buf
;
181 __setup("trace_options=", set_trace_boot_options
);
184 unsigned long long ns2usecs(cycle_t nsec
)
192 * The global_trace is the descriptor that holds the tracing
193 * buffers for the live tracing. For each CPU, it contains
194 * a link list of pages that will store trace entries. The
195 * page descriptor of the pages in the memory is used to hold
196 * the link list by linking the lru item in the page descriptor
197 * to each of the pages in the buffer per CPU.
199 * For each active CPU there is a data field that holds the
200 * pages for the buffer for that CPU. Each CPU has the same number
201 * of pages allocated for its buffer.
203 static struct trace_array global_trace
;
205 LIST_HEAD(ftrace_trace_arrays
);
207 int trace_array_get(struct trace_array
*this_tr
)
209 struct trace_array
*tr
;
212 mutex_lock(&trace_types_lock
);
213 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
220 mutex_unlock(&trace_types_lock
);
225 static void __trace_array_put(struct trace_array
*this_tr
)
227 WARN_ON(!this_tr
->ref
);
231 void trace_array_put(struct trace_array
*this_tr
)
233 mutex_lock(&trace_types_lock
);
234 __trace_array_put(this_tr
);
235 mutex_unlock(&trace_types_lock
);
238 int filter_check_discard(struct ftrace_event_file
*file
, void *rec
,
239 struct ring_buffer
*buffer
,
240 struct ring_buffer_event
*event
)
242 if (unlikely(file
->flags
& FTRACE_EVENT_FL_FILTERED
) &&
243 !filter_match_preds(file
->filter
, rec
)) {
244 ring_buffer_discard_commit(buffer
, event
);
250 EXPORT_SYMBOL_GPL(filter_check_discard
);
252 int call_filter_check_discard(struct ftrace_event_call
*call
, void *rec
,
253 struct ring_buffer
*buffer
,
254 struct ring_buffer_event
*event
)
256 if (unlikely(call
->flags
& TRACE_EVENT_FL_FILTERED
) &&
257 !filter_match_preds(call
->filter
, rec
)) {
258 ring_buffer_discard_commit(buffer
, event
);
264 EXPORT_SYMBOL_GPL(call_filter_check_discard
);
266 cycle_t
buffer_ftrace_now(struct trace_buffer
*buf
, int cpu
)
270 /* Early boot up does not have a buffer yet */
272 return trace_clock_local();
274 ts
= ring_buffer_time_stamp(buf
->buffer
, cpu
);
275 ring_buffer_normalize_time_stamp(buf
->buffer
, cpu
, &ts
);
280 cycle_t
ftrace_now(int cpu
)
282 return buffer_ftrace_now(&global_trace
.trace_buffer
, cpu
);
286 * tracing_is_enabled - Show if global_trace has been disabled
288 * Shows if the global trace has been enabled or not. It uses the
289 * mirror flag "buffer_disabled" to be used in fast paths such as for
290 * the irqsoff tracer. But it may be inaccurate due to races. If you
291 * need to know the accurate state, use tracing_is_on() which is a little
292 * slower, but accurate.
294 int tracing_is_enabled(void)
297 * For quick access (irqsoff uses this in fast path), just
298 * return the mirror variable of the state of the ring buffer.
299 * It's a little racy, but we don't really care.
302 return !global_trace
.buffer_disabled
;
306 * trace_buf_size is the size in bytes that is allocated
307 * for a buffer. Note, the number of bytes is always rounded
310 * This number is purposely set to a low number of 16384.
311 * If the dump on oops happens, it will be much appreciated
312 * to not have to wait for all that output. Anyway this can be
313 * boot time and run time configurable.
315 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
317 static unsigned long trace_buf_size
= TRACE_BUF_SIZE_DEFAULT
;
319 /* trace_types holds a link list of available tracers. */
320 static struct tracer
*trace_types __read_mostly
;
323 * trace_types_lock is used to protect the trace_types list.
325 DEFINE_MUTEX(trace_types_lock
);
328 * serialize the access of the ring buffer
330 * ring buffer serializes readers, but it is low level protection.
331 * The validity of the events (which returns by ring_buffer_peek() ..etc)
332 * are not protected by ring buffer.
334 * The content of events may become garbage if we allow other process consumes
335 * these events concurrently:
336 * A) the page of the consumed events may become a normal page
337 * (not reader page) in ring buffer, and this page will be rewrited
338 * by events producer.
339 * B) The page of the consumed events may become a page for splice_read,
340 * and this page will be returned to system.
342 * These primitives allow multi process access to different cpu ring buffer
345 * These primitives don't distinguish read-only and read-consume access.
346 * Multi read-only access are also serialized.
350 static DECLARE_RWSEM(all_cpu_access_lock
);
351 static DEFINE_PER_CPU(struct mutex
, cpu_access_lock
);
353 static inline void trace_access_lock(int cpu
)
355 if (cpu
== RING_BUFFER_ALL_CPUS
) {
356 /* gain it for accessing the whole ring buffer. */
357 down_write(&all_cpu_access_lock
);
359 /* gain it for accessing a cpu ring buffer. */
361 /* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
362 down_read(&all_cpu_access_lock
);
364 /* Secondly block other access to this @cpu ring buffer. */
365 mutex_lock(&per_cpu(cpu_access_lock
, cpu
));
369 static inline void trace_access_unlock(int cpu
)
371 if (cpu
== RING_BUFFER_ALL_CPUS
) {
372 up_write(&all_cpu_access_lock
);
374 mutex_unlock(&per_cpu(cpu_access_lock
, cpu
));
375 up_read(&all_cpu_access_lock
);
379 static inline void trace_access_lock_init(void)
383 for_each_possible_cpu(cpu
)
384 mutex_init(&per_cpu(cpu_access_lock
, cpu
));
389 static DEFINE_MUTEX(access_lock
);
391 static inline void trace_access_lock(int cpu
)
394 mutex_lock(&access_lock
);
397 static inline void trace_access_unlock(int cpu
)
400 mutex_unlock(&access_lock
);
403 static inline void trace_access_lock_init(void)
409 /* trace_flags holds trace_options default values */
410 unsigned long trace_flags
= TRACE_ITER_PRINT_PARENT
| TRACE_ITER_PRINTK
|
411 TRACE_ITER_ANNOTATE
| TRACE_ITER_CONTEXT_INFO
| TRACE_ITER_SLEEP_TIME
|
412 TRACE_ITER_GRAPH_TIME
| TRACE_ITER_RECORD_CMD
| TRACE_ITER_OVERWRITE
|
413 TRACE_ITER_IRQ_INFO
| TRACE_ITER_MARKERS
| TRACE_ITER_FUNCTION
;
415 static void tracer_tracing_on(struct trace_array
*tr
)
417 if (tr
->trace_buffer
.buffer
)
418 ring_buffer_record_on(tr
->trace_buffer
.buffer
);
420 * This flag is looked at when buffers haven't been allocated
421 * yet, or by some tracers (like irqsoff), that just want to
422 * know if the ring buffer has been disabled, but it can handle
423 * races of where it gets disabled but we still do a record.
424 * As the check is in the fast path of the tracers, it is more
425 * important to be fast than accurate.
427 tr
->buffer_disabled
= 0;
428 /* Make the flag seen by readers */
433 * tracing_on - enable tracing buffers
435 * This function enables tracing buffers that may have been
436 * disabled with tracing_off.
438 void tracing_on(void)
440 tracer_tracing_on(&global_trace
);
442 EXPORT_SYMBOL_GPL(tracing_on
);
445 * __trace_puts - write a constant string into the trace buffer.
446 * @ip: The address of the caller
447 * @str: The constant string to write
448 * @size: The size of the string.
450 int __trace_puts(unsigned long ip
, const char *str
, int size
)
452 struct ring_buffer_event
*event
;
453 struct ring_buffer
*buffer
;
454 struct print_entry
*entry
;
455 unsigned long irq_flags
;
458 alloc
= sizeof(*entry
) + size
+ 2; /* possible \n added */
460 local_save_flags(irq_flags
);
461 buffer
= global_trace
.trace_buffer
.buffer
;
462 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, alloc
,
463 irq_flags
, preempt_count());
467 entry
= ring_buffer_event_data(event
);
470 memcpy(&entry
->buf
, str
, size
);
472 /* Add a newline if necessary */
473 if (entry
->buf
[size
- 1] != '\n') {
474 entry
->buf
[size
] = '\n';
475 entry
->buf
[size
+ 1] = '\0';
477 entry
->buf
[size
] = '\0';
479 __buffer_unlock_commit(buffer
, event
);
483 EXPORT_SYMBOL_GPL(__trace_puts
);
486 * __trace_bputs - write the pointer to a constant string into trace buffer
487 * @ip: The address of the caller
488 * @str: The constant string to write to the buffer to
490 int __trace_bputs(unsigned long ip
, const char *str
)
492 struct ring_buffer_event
*event
;
493 struct ring_buffer
*buffer
;
494 struct bputs_entry
*entry
;
495 unsigned long irq_flags
;
496 int size
= sizeof(struct bputs_entry
);
498 local_save_flags(irq_flags
);
499 buffer
= global_trace
.trace_buffer
.buffer
;
500 event
= trace_buffer_lock_reserve(buffer
, TRACE_BPUTS
, size
,
501 irq_flags
, preempt_count());
505 entry
= ring_buffer_event_data(event
);
509 __buffer_unlock_commit(buffer
, event
);
513 EXPORT_SYMBOL_GPL(__trace_bputs
);
515 #ifdef CONFIG_TRACER_SNAPSHOT
517 * trace_snapshot - take a snapshot of the current buffer.
519 * This causes a swap between the snapshot buffer and the current live
520 * tracing buffer. You can use this to take snapshots of the live
521 * trace when some condition is triggered, but continue to trace.
523 * Note, make sure to allocate the snapshot with either
524 * a tracing_snapshot_alloc(), or by doing it manually
525 * with: echo 1 > /sys/kernel/debug/tracing/snapshot
527 * If the snapshot buffer is not allocated, it will stop tracing.
528 * Basically making a permanent snapshot.
530 void tracing_snapshot(void)
532 struct trace_array
*tr
= &global_trace
;
533 struct tracer
*tracer
= tr
->current_trace
;
537 internal_trace_puts("*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
538 internal_trace_puts("*** snapshot is being ignored ***\n");
542 if (!tr
->allocated_snapshot
) {
543 internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n");
544 internal_trace_puts("*** stopping trace here! ***\n");
549 /* Note, snapshot can not be used when the tracer uses it */
550 if (tracer
->use_max_tr
) {
551 internal_trace_puts("*** LATENCY TRACER ACTIVE ***\n");
552 internal_trace_puts("*** Can not use snapshot (sorry) ***\n");
556 local_irq_save(flags
);
557 update_max_tr(tr
, current
, smp_processor_id());
558 local_irq_restore(flags
);
560 EXPORT_SYMBOL_GPL(tracing_snapshot
);
562 static int resize_buffer_duplicate_size(struct trace_buffer
*trace_buf
,
563 struct trace_buffer
*size_buf
, int cpu_id
);
564 static void set_buffer_entries(struct trace_buffer
*buf
, unsigned long val
);
566 static int alloc_snapshot(struct trace_array
*tr
)
570 if (!tr
->allocated_snapshot
) {
572 /* allocate spare buffer */
573 ret
= resize_buffer_duplicate_size(&tr
->max_buffer
,
574 &tr
->trace_buffer
, RING_BUFFER_ALL_CPUS
);
578 tr
->allocated_snapshot
= true;
584 void free_snapshot(struct trace_array
*tr
)
587 * We don't free the ring buffer. instead, resize it because
588 * The max_tr ring buffer has some state (e.g. ring->clock) and
589 * we want preserve it.
591 ring_buffer_resize(tr
->max_buffer
.buffer
, 1, RING_BUFFER_ALL_CPUS
);
592 set_buffer_entries(&tr
->max_buffer
, 1);
593 tracing_reset_online_cpus(&tr
->max_buffer
);
594 tr
->allocated_snapshot
= false;
598 * tracing_alloc_snapshot - allocate snapshot buffer.
600 * This only allocates the snapshot buffer if it isn't already
601 * allocated - it doesn't also take a snapshot.
603 * This is meant to be used in cases where the snapshot buffer needs
604 * to be set up for events that can't sleep but need to be able to
605 * trigger a snapshot.
607 int tracing_alloc_snapshot(void)
609 struct trace_array
*tr
= &global_trace
;
612 ret
= alloc_snapshot(tr
);
617 EXPORT_SYMBOL_GPL(tracing_alloc_snapshot
);
620 * trace_snapshot_alloc - allocate and take a snapshot of the current buffer.
622 * This is similar to trace_snapshot(), but it will allocate the
623 * snapshot buffer if it isn't already allocated. Use this only
624 * where it is safe to sleep, as the allocation may sleep.
626 * This causes a swap between the snapshot buffer and the current live
627 * tracing buffer. You can use this to take snapshots of the live
628 * trace when some condition is triggered, but continue to trace.
630 void tracing_snapshot_alloc(void)
634 ret
= tracing_alloc_snapshot();
640 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc
);
642 void tracing_snapshot(void)
644 WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
646 EXPORT_SYMBOL_GPL(tracing_snapshot
);
647 int tracing_alloc_snapshot(void)
649 WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used");
652 EXPORT_SYMBOL_GPL(tracing_alloc_snapshot
);
653 void tracing_snapshot_alloc(void)
658 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc
);
659 #endif /* CONFIG_TRACER_SNAPSHOT */
661 static void tracer_tracing_off(struct trace_array
*tr
)
663 if (tr
->trace_buffer
.buffer
)
664 ring_buffer_record_off(tr
->trace_buffer
.buffer
);
666 * This flag is looked at when buffers haven't been allocated
667 * yet, or by some tracers (like irqsoff), that just want to
668 * know if the ring buffer has been disabled, but it can handle
669 * races of where it gets disabled but we still do a record.
670 * As the check is in the fast path of the tracers, it is more
671 * important to be fast than accurate.
673 tr
->buffer_disabled
= 1;
674 /* Make the flag seen by readers */
679 * tracing_off - turn off tracing buffers
681 * This function stops the tracing buffers from recording data.
682 * It does not disable any overhead the tracers themselves may
683 * be causing. This function simply causes all recording to
684 * the ring buffers to fail.
686 void tracing_off(void)
688 tracer_tracing_off(&global_trace
);
690 EXPORT_SYMBOL_GPL(tracing_off
);
692 void disable_trace_on_warning(void)
694 if (__disable_trace_on_warning
)
699 * tracer_tracing_is_on - show real state of ring buffer enabled
700 * @tr : the trace array to know if ring buffer is enabled
702 * Shows real state of the ring buffer if it is enabled or not.
704 static int tracer_tracing_is_on(struct trace_array
*tr
)
706 if (tr
->trace_buffer
.buffer
)
707 return ring_buffer_record_is_on(tr
->trace_buffer
.buffer
);
708 return !tr
->buffer_disabled
;
712 * tracing_is_on - show state of ring buffers enabled
714 int tracing_is_on(void)
716 return tracer_tracing_is_on(&global_trace
);
718 EXPORT_SYMBOL_GPL(tracing_is_on
);
720 static int __init
set_buf_size(char *str
)
722 unsigned long buf_size
;
726 buf_size
= memparse(str
, &str
);
727 /* nr_entries can not be zero */
730 trace_buf_size
= buf_size
;
733 __setup("trace_buf_size=", set_buf_size
);
735 static int __init
set_tracing_thresh(char *str
)
737 unsigned long threshold
;
742 ret
= kstrtoul(str
, 0, &threshold
);
745 tracing_thresh
= threshold
* 1000;
748 __setup("tracing_thresh=", set_tracing_thresh
);
750 unsigned long nsecs_to_usecs(unsigned long nsecs
)
755 /* These must match the bit postions in trace_iterator_flags */
756 static const char *trace_options
[] = {
789 int in_ns
; /* is this clock in nanoseconds? */
791 { trace_clock_local
, "local", 1 },
792 { trace_clock_global
, "global", 1 },
793 { trace_clock_counter
, "counter", 0 },
794 { trace_clock_jiffies
, "uptime", 1 },
795 { trace_clock
, "perf", 1 },
800 * trace_parser_get_init - gets the buffer for trace parser
802 int trace_parser_get_init(struct trace_parser
*parser
, int size
)
804 memset(parser
, 0, sizeof(*parser
));
806 parser
->buffer
= kmalloc(size
, GFP_KERNEL
);
815 * trace_parser_put - frees the buffer for trace parser
817 void trace_parser_put(struct trace_parser
*parser
)
819 kfree(parser
->buffer
);
823 * trace_get_user - reads the user input string separated by space
824 * (matched by isspace(ch))
826 * For each string found the 'struct trace_parser' is updated,
827 * and the function returns.
829 * Returns number of bytes read.
831 * See kernel/trace/trace.h for 'struct trace_parser' details.
833 int trace_get_user(struct trace_parser
*parser
, const char __user
*ubuf
,
834 size_t cnt
, loff_t
*ppos
)
841 trace_parser_clear(parser
);
843 ret
= get_user(ch
, ubuf
++);
851 * The parser is not finished with the last write,
852 * continue reading the user input without skipping spaces.
855 /* skip white space */
856 while (cnt
&& isspace(ch
)) {
857 ret
= get_user(ch
, ubuf
++);
864 /* only spaces were written */
874 /* read the non-space input */
875 while (cnt
&& !isspace(ch
)) {
876 if (parser
->idx
< parser
->size
- 1)
877 parser
->buffer
[parser
->idx
++] = ch
;
882 ret
= get_user(ch
, ubuf
++);
889 /* We either got finished input or we have to wait for another call. */
891 parser
->buffer
[parser
->idx
] = 0;
892 parser
->cont
= false;
893 } else if (parser
->idx
< parser
->size
- 1) {
895 parser
->buffer
[parser
->idx
++] = ch
;
908 ssize_t
trace_seq_to_user(struct trace_seq
*s
, char __user
*ubuf
, size_t cnt
)
916 if (s
->len
<= s
->readpos
)
919 len
= s
->len
- s
->readpos
;
922 ret
= copy_to_user(ubuf
, s
->buffer
+ s
->readpos
, cnt
);
932 static ssize_t
trace_seq_to_buffer(struct trace_seq
*s
, void *buf
, size_t cnt
)
936 if (s
->len
<= s
->readpos
)
939 len
= s
->len
- s
->readpos
;
942 memcpy(buf
, s
->buffer
+ s
->readpos
, cnt
);
949 * ftrace_max_lock is used to protect the swapping of buffers
950 * when taking a max snapshot. The buffers themselves are
951 * protected by per_cpu spinlocks. But the action of the swap
952 * needs its own lock.
954 * This is defined as a arch_spinlock_t in order to help
955 * with performance when lockdep debugging is enabled.
957 * It is also used in other places outside the update_max_tr
958 * so it needs to be defined outside of the
959 * CONFIG_TRACER_MAX_TRACE.
961 static arch_spinlock_t ftrace_max_lock
=
962 (arch_spinlock_t
)__ARCH_SPIN_LOCK_UNLOCKED
;
964 unsigned long __read_mostly tracing_thresh
;
966 #ifdef CONFIG_TRACER_MAX_TRACE
967 unsigned long __read_mostly tracing_max_latency
;
970 * Copy the new maximum trace into the separate maximum-trace
971 * structure. (this way the maximum trace is permanently saved,
972 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
975 __update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
977 struct trace_buffer
*trace_buf
= &tr
->trace_buffer
;
978 struct trace_buffer
*max_buf
= &tr
->max_buffer
;
979 struct trace_array_cpu
*data
= per_cpu_ptr(trace_buf
->data
, cpu
);
980 struct trace_array_cpu
*max_data
= per_cpu_ptr(max_buf
->data
, cpu
);
983 max_buf
->time_start
= data
->preempt_timestamp
;
985 max_data
->saved_latency
= tracing_max_latency
;
986 max_data
->critical_start
= data
->critical_start
;
987 max_data
->critical_end
= data
->critical_end
;
989 memcpy(max_data
->comm
, tsk
->comm
, TASK_COMM_LEN
);
990 max_data
->pid
= tsk
->pid
;
992 * If tsk == current, then use current_uid(), as that does not use
993 * RCU. The irq tracer can be called out of RCU scope.
996 max_data
->uid
= current_uid();
998 max_data
->uid
= task_uid(tsk
);
1000 max_data
->nice
= tsk
->static_prio
- 20 - MAX_RT_PRIO
;
1001 max_data
->policy
= tsk
->policy
;
1002 max_data
->rt_priority
= tsk
->rt_priority
;
1004 /* record this tasks comm */
1005 tracing_record_cmdline(tsk
);
1009 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
1011 * @tsk: the task with the latency
1012 * @cpu: The cpu that initiated the trace.
1014 * Flip the buffers between the @tr and the max_tr and record information
1015 * about which task was the cause of this latency.
1018 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
1020 struct ring_buffer
*buf
;
1025 WARN_ON_ONCE(!irqs_disabled());
1027 if (!tr
->allocated_snapshot
) {
1028 /* Only the nop tracer should hit this when disabling */
1029 WARN_ON_ONCE(tr
->current_trace
!= &nop_trace
);
1033 arch_spin_lock(&ftrace_max_lock
);
1035 buf
= tr
->trace_buffer
.buffer
;
1036 tr
->trace_buffer
.buffer
= tr
->max_buffer
.buffer
;
1037 tr
->max_buffer
.buffer
= buf
;
1039 __update_max_tr(tr
, tsk
, cpu
);
1040 arch_spin_unlock(&ftrace_max_lock
);
1044 * update_max_tr_single - only copy one trace over, and reset the rest
1046 * @tsk - task with the latency
1047 * @cpu - the cpu of the buffer to copy.
1049 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
1052 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
1059 WARN_ON_ONCE(!irqs_disabled());
1060 if (!tr
->allocated_snapshot
) {
1061 /* Only the nop tracer should hit this when disabling */
1062 WARN_ON_ONCE(tr
->current_trace
!= &nop_trace
);
1066 arch_spin_lock(&ftrace_max_lock
);
1068 ret
= ring_buffer_swap_cpu(tr
->max_buffer
.buffer
, tr
->trace_buffer
.buffer
, cpu
);
1070 if (ret
== -EBUSY
) {
1072 * We failed to swap the buffer due to a commit taking
1073 * place on this CPU. We fail to record, but we reset
1074 * the max trace buffer (no one writes directly to it)
1075 * and flag that it failed.
1077 trace_array_printk_buf(tr
->max_buffer
.buffer
, _THIS_IP_
,
1078 "Failed to swap buffers due to commit in progress\n");
1081 WARN_ON_ONCE(ret
&& ret
!= -EAGAIN
&& ret
!= -EBUSY
);
1083 __update_max_tr(tr
, tsk
, cpu
);
1084 arch_spin_unlock(&ftrace_max_lock
);
1086 #endif /* CONFIG_TRACER_MAX_TRACE */
1088 static void default_wait_pipe(struct trace_iterator
*iter
)
1090 /* Iterators are static, they should be filled or empty */
1091 if (trace_buffer_iter(iter
, iter
->cpu_file
))
1094 ring_buffer_wait(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
1097 #ifdef CONFIG_FTRACE_STARTUP_TEST
1098 static int run_tracer_selftest(struct tracer
*type
)
1100 struct trace_array
*tr
= &global_trace
;
1101 struct tracer
*saved_tracer
= tr
->current_trace
;
1104 if (!type
->selftest
|| tracing_selftest_disabled
)
1108 * Run a selftest on this tracer.
1109 * Here we reset the trace buffer, and set the current
1110 * tracer to be this tracer. The tracer can then run some
1111 * internal tracing to verify that everything is in order.
1112 * If we fail, we do not register this tracer.
1114 tracing_reset_online_cpus(&tr
->trace_buffer
);
1116 tr
->current_trace
= type
;
1118 #ifdef CONFIG_TRACER_MAX_TRACE
1119 if (type
->use_max_tr
) {
1120 /* If we expanded the buffers, make sure the max is expanded too */
1121 if (ring_buffer_expanded
)
1122 ring_buffer_resize(tr
->max_buffer
.buffer
, trace_buf_size
,
1123 RING_BUFFER_ALL_CPUS
);
1124 tr
->allocated_snapshot
= true;
1128 /* the test is responsible for initializing and enabling */
1129 pr_info("Testing tracer %s: ", type
->name
);
1130 ret
= type
->selftest(type
, tr
);
1131 /* the test is responsible for resetting too */
1132 tr
->current_trace
= saved_tracer
;
1134 printk(KERN_CONT
"FAILED!\n");
1135 /* Add the warning after printing 'FAILED' */
1139 /* Only reset on passing, to avoid touching corrupted buffers */
1140 tracing_reset_online_cpus(&tr
->trace_buffer
);
1142 #ifdef CONFIG_TRACER_MAX_TRACE
1143 if (type
->use_max_tr
) {
1144 tr
->allocated_snapshot
= false;
1146 /* Shrink the max buffer again */
1147 if (ring_buffer_expanded
)
1148 ring_buffer_resize(tr
->max_buffer
.buffer
, 1,
1149 RING_BUFFER_ALL_CPUS
);
1153 printk(KERN_CONT
"PASSED\n");
1157 static inline int run_tracer_selftest(struct tracer
*type
)
1161 #endif /* CONFIG_FTRACE_STARTUP_TEST */
1164 * register_tracer - register a tracer with the ftrace system.
1165 * @type - the plugin for the tracer
1167 * Register a new plugin tracer.
1169 int register_tracer(struct tracer
*type
)
1175 pr_info("Tracer must have a name\n");
1179 if (strlen(type
->name
) >= MAX_TRACER_SIZE
) {
1180 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE
);
1184 mutex_lock(&trace_types_lock
);
1186 tracing_selftest_running
= true;
1188 for (t
= trace_types
; t
; t
= t
->next
) {
1189 if (strcmp(type
->name
, t
->name
) == 0) {
1191 pr_info("Tracer %s already registered\n",
1198 if (!type
->set_flag
)
1199 type
->set_flag
= &dummy_set_flag
;
1201 type
->flags
= &dummy_tracer_flags
;
1203 if (!type
->flags
->opts
)
1204 type
->flags
->opts
= dummy_tracer_opt
;
1205 if (!type
->wait_pipe
)
1206 type
->wait_pipe
= default_wait_pipe
;
1208 ret
= run_tracer_selftest(type
);
1212 type
->next
= trace_types
;
1216 tracing_selftest_running
= false;
1217 mutex_unlock(&trace_types_lock
);
1219 if (ret
|| !default_bootup_tracer
)
1222 if (strncmp(default_bootup_tracer
, type
->name
, MAX_TRACER_SIZE
))
1225 printk(KERN_INFO
"Starting tracer '%s'\n", type
->name
);
1226 /* Do we want this tracer to start on bootup? */
1227 tracing_set_tracer(type
->name
);
1228 default_bootup_tracer
= NULL
;
1229 /* disable other selftests, since this will break it. */
1230 tracing_selftest_disabled
= true;
1231 #ifdef CONFIG_FTRACE_STARTUP_TEST
1232 printk(KERN_INFO
"Disabling FTRACE selftests due to running tracer '%s'\n",
1240 void tracing_reset(struct trace_buffer
*buf
, int cpu
)
1242 struct ring_buffer
*buffer
= buf
->buffer
;
1247 ring_buffer_record_disable(buffer
);
1249 /* Make sure all commits have finished */
1250 synchronize_sched();
1251 ring_buffer_reset_cpu(buffer
, cpu
);
1253 ring_buffer_record_enable(buffer
);
1256 void tracing_reset_online_cpus(struct trace_buffer
*buf
)
1258 struct ring_buffer
*buffer
= buf
->buffer
;
1264 ring_buffer_record_disable(buffer
);
1266 /* Make sure all commits have finished */
1267 synchronize_sched();
1269 buf
->time_start
= buffer_ftrace_now(buf
, buf
->cpu
);
1271 for_each_online_cpu(cpu
)
1272 ring_buffer_reset_cpu(buffer
, cpu
);
1274 ring_buffer_record_enable(buffer
);
1277 /* Must have trace_types_lock held */
1278 void tracing_reset_all_online_cpus(void)
1280 struct trace_array
*tr
;
1282 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
1283 tracing_reset_online_cpus(&tr
->trace_buffer
);
1284 #ifdef CONFIG_TRACER_MAX_TRACE
1285 tracing_reset_online_cpus(&tr
->max_buffer
);
1290 #define SAVED_CMDLINES 128
1291 #define NO_CMDLINE_MAP UINT_MAX
1292 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
1293 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
1294 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
1295 static int cmdline_idx
;
1296 static arch_spinlock_t trace_cmdline_lock
= __ARCH_SPIN_LOCK_UNLOCKED
;
1298 /* temporary disable recording */
1299 static atomic_t trace_record_cmdline_disabled __read_mostly
;
1301 static void trace_init_cmdlines(void)
1303 memset(&map_pid_to_cmdline
, NO_CMDLINE_MAP
, sizeof(map_pid_to_cmdline
));
1304 memset(&map_cmdline_to_pid
, NO_CMDLINE_MAP
, sizeof(map_cmdline_to_pid
));
1308 int is_tracing_stopped(void)
1310 return global_trace
.stop_count
;
1314 * tracing_start - quick start of the tracer
1316 * If tracing is enabled but was stopped by tracing_stop,
1317 * this will start the tracer back up.
1319 void tracing_start(void)
1321 struct ring_buffer
*buffer
;
1322 unsigned long flags
;
1324 if (tracing_disabled
)
1327 raw_spin_lock_irqsave(&global_trace
.start_lock
, flags
);
1328 if (--global_trace
.stop_count
) {
1329 if (global_trace
.stop_count
< 0) {
1330 /* Someone screwed up their debugging */
1332 global_trace
.stop_count
= 0;
1337 /* Prevent the buffers from switching */
1338 arch_spin_lock(&ftrace_max_lock
);
1340 buffer
= global_trace
.trace_buffer
.buffer
;
1342 ring_buffer_record_enable(buffer
);
1344 #ifdef CONFIG_TRACER_MAX_TRACE
1345 buffer
= global_trace
.max_buffer
.buffer
;
1347 ring_buffer_record_enable(buffer
);
1350 arch_spin_unlock(&ftrace_max_lock
);
1354 raw_spin_unlock_irqrestore(&global_trace
.start_lock
, flags
);
1357 static void tracing_start_tr(struct trace_array
*tr
)
1359 struct ring_buffer
*buffer
;
1360 unsigned long flags
;
1362 if (tracing_disabled
)
1365 /* If global, we need to also start the max tracer */
1366 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
1367 return tracing_start();
1369 raw_spin_lock_irqsave(&tr
->start_lock
, flags
);
1371 if (--tr
->stop_count
) {
1372 if (tr
->stop_count
< 0) {
1373 /* Someone screwed up their debugging */
1380 buffer
= tr
->trace_buffer
.buffer
;
1382 ring_buffer_record_enable(buffer
);
1385 raw_spin_unlock_irqrestore(&tr
->start_lock
, flags
);
1389 * tracing_stop - quick stop of the tracer
1391 * Light weight way to stop tracing. Use in conjunction with
1394 void tracing_stop(void)
1396 struct ring_buffer
*buffer
;
1397 unsigned long flags
;
1400 raw_spin_lock_irqsave(&global_trace
.start_lock
, flags
);
1401 if (global_trace
.stop_count
++)
1404 /* Prevent the buffers from switching */
1405 arch_spin_lock(&ftrace_max_lock
);
1407 buffer
= global_trace
.trace_buffer
.buffer
;
1409 ring_buffer_record_disable(buffer
);
1411 #ifdef CONFIG_TRACER_MAX_TRACE
1412 buffer
= global_trace
.max_buffer
.buffer
;
1414 ring_buffer_record_disable(buffer
);
1417 arch_spin_unlock(&ftrace_max_lock
);
1420 raw_spin_unlock_irqrestore(&global_trace
.start_lock
, flags
);
1423 static void tracing_stop_tr(struct trace_array
*tr
)
1425 struct ring_buffer
*buffer
;
1426 unsigned long flags
;
1428 /* If global, we need to also stop the max tracer */
1429 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
1430 return tracing_stop();
1432 raw_spin_lock_irqsave(&tr
->start_lock
, flags
);
1433 if (tr
->stop_count
++)
1436 buffer
= tr
->trace_buffer
.buffer
;
1438 ring_buffer_record_disable(buffer
);
1441 raw_spin_unlock_irqrestore(&tr
->start_lock
, flags
);
1444 void trace_stop_cmdline_recording(void);
1446 static void trace_save_cmdline(struct task_struct
*tsk
)
1450 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
1454 * It's not the end of the world if we don't get
1455 * the lock, but we also don't want to spin
1456 * nor do we want to disable interrupts,
1457 * so if we miss here, then better luck next time.
1459 if (!arch_spin_trylock(&trace_cmdline_lock
))
1462 idx
= map_pid_to_cmdline
[tsk
->pid
];
1463 if (idx
== NO_CMDLINE_MAP
) {
1464 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
1467 * Check whether the cmdline buffer at idx has a pid
1468 * mapped. We are going to overwrite that entry so we
1469 * need to clear the map_pid_to_cmdline. Otherwise we
1470 * would read the new comm for the old pid.
1472 pid
= map_cmdline_to_pid
[idx
];
1473 if (pid
!= NO_CMDLINE_MAP
)
1474 map_pid_to_cmdline
[pid
] = NO_CMDLINE_MAP
;
1476 map_cmdline_to_pid
[idx
] = tsk
->pid
;
1477 map_pid_to_cmdline
[tsk
->pid
] = idx
;
1482 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
1484 arch_spin_unlock(&trace_cmdline_lock
);
1487 void trace_find_cmdline(int pid
, char comm
[])
1492 strcpy(comm
, "<idle>");
1496 if (WARN_ON_ONCE(pid
< 0)) {
1497 strcpy(comm
, "<XXX>");
1501 if (pid
> PID_MAX_DEFAULT
) {
1502 strcpy(comm
, "<...>");
1507 arch_spin_lock(&trace_cmdline_lock
);
1508 map
= map_pid_to_cmdline
[pid
];
1509 if (map
!= NO_CMDLINE_MAP
)
1510 strcpy(comm
, saved_cmdlines
[map
]);
1512 strcpy(comm
, "<...>");
1514 arch_spin_unlock(&trace_cmdline_lock
);
1518 void tracing_record_cmdline(struct task_struct
*tsk
)
1520 if (atomic_read(&trace_record_cmdline_disabled
) || !tracing_is_on())
1523 if (!__this_cpu_read(trace_cmdline_save
))
1526 __this_cpu_write(trace_cmdline_save
, false);
1528 trace_save_cmdline(tsk
);
1532 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
,
1535 struct task_struct
*tsk
= current
;
1537 entry
->preempt_count
= pc
& 0xff;
1538 entry
->pid
= (tsk
) ? tsk
->pid
: 0;
1540 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1541 (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
1543 TRACE_FLAG_IRQS_NOSUPPORT
|
1545 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
1546 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
1547 (tif_need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0) |
1548 (test_preempt_need_resched() ? TRACE_FLAG_PREEMPT_RESCHED
: 0);
1550 EXPORT_SYMBOL_GPL(tracing_generic_entry_update
);
1552 struct ring_buffer_event
*
1553 trace_buffer_lock_reserve(struct ring_buffer
*buffer
,
1556 unsigned long flags
, int pc
)
1558 struct ring_buffer_event
*event
;
1560 event
= ring_buffer_lock_reserve(buffer
, len
);
1561 if (event
!= NULL
) {
1562 struct trace_entry
*ent
= ring_buffer_event_data(event
);
1564 tracing_generic_entry_update(ent
, flags
, pc
);
1572 __buffer_unlock_commit(struct ring_buffer
*buffer
, struct ring_buffer_event
*event
)
1574 __this_cpu_write(trace_cmdline_save
, true);
1575 ring_buffer_unlock_commit(buffer
, event
);
1579 __trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1580 struct ring_buffer_event
*event
,
1581 unsigned long flags
, int pc
)
1583 __buffer_unlock_commit(buffer
, event
);
1585 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1586 ftrace_trace_userstack(buffer
, flags
, pc
);
1589 void trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1590 struct ring_buffer_event
*event
,
1591 unsigned long flags
, int pc
)
1593 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
);
1595 EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit
);
1597 struct ring_buffer_event
*
1598 trace_event_buffer_lock_reserve(struct ring_buffer
**current_rb
,
1599 struct ftrace_event_file
*ftrace_file
,
1600 int type
, unsigned long len
,
1601 unsigned long flags
, int pc
)
1603 *current_rb
= ftrace_file
->tr
->trace_buffer
.buffer
;
1604 return trace_buffer_lock_reserve(*current_rb
,
1605 type
, len
, flags
, pc
);
1607 EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve
);
1609 struct ring_buffer_event
*
1610 trace_current_buffer_lock_reserve(struct ring_buffer
**current_rb
,
1611 int type
, unsigned long len
,
1612 unsigned long flags
, int pc
)
1614 *current_rb
= global_trace
.trace_buffer
.buffer
;
1615 return trace_buffer_lock_reserve(*current_rb
,
1616 type
, len
, flags
, pc
);
1618 EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve
);
1620 void trace_current_buffer_unlock_commit(struct ring_buffer
*buffer
,
1621 struct ring_buffer_event
*event
,
1622 unsigned long flags
, int pc
)
1624 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
);
1626 EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit
);
1628 void trace_buffer_unlock_commit_regs(struct ring_buffer
*buffer
,
1629 struct ring_buffer_event
*event
,
1630 unsigned long flags
, int pc
,
1631 struct pt_regs
*regs
)
1633 __buffer_unlock_commit(buffer
, event
);
1635 ftrace_trace_stack_regs(buffer
, flags
, 0, pc
, regs
);
1636 ftrace_trace_userstack(buffer
, flags
, pc
);
1638 EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit_regs
);
1640 void trace_current_buffer_discard_commit(struct ring_buffer
*buffer
,
1641 struct ring_buffer_event
*event
)
1643 ring_buffer_discard_commit(buffer
, event
);
1645 EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit
);
1648 trace_function(struct trace_array
*tr
,
1649 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
1652 struct ftrace_event_call
*call
= &event_function
;
1653 struct ring_buffer
*buffer
= tr
->trace_buffer
.buffer
;
1654 struct ring_buffer_event
*event
;
1655 struct ftrace_entry
*entry
;
1657 /* If we are reading the ring buffer, don't trace */
1658 if (unlikely(__this_cpu_read(ftrace_cpu_disabled
)))
1661 event
= trace_buffer_lock_reserve(buffer
, TRACE_FN
, sizeof(*entry
),
1665 entry
= ring_buffer_event_data(event
);
1667 entry
->parent_ip
= parent_ip
;
1669 if (!call_filter_check_discard(call
, entry
, buffer
, event
))
1670 __buffer_unlock_commit(buffer
, event
);
1673 #ifdef CONFIG_STACKTRACE
1675 #define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
1676 struct ftrace_stack
{
1677 unsigned long calls
[FTRACE_STACK_MAX_ENTRIES
];
1680 static DEFINE_PER_CPU(struct ftrace_stack
, ftrace_stack
);
1681 static DEFINE_PER_CPU(int, ftrace_stack_reserve
);
1683 static void __ftrace_trace_stack(struct ring_buffer
*buffer
,
1684 unsigned long flags
,
1685 int skip
, int pc
, struct pt_regs
*regs
)
1687 struct ftrace_event_call
*call
= &event_kernel_stack
;
1688 struct ring_buffer_event
*event
;
1689 struct stack_entry
*entry
;
1690 struct stack_trace trace
;
1692 int size
= FTRACE_STACK_ENTRIES
;
1694 trace
.nr_entries
= 0;
1698 * Since events can happen in NMIs there's no safe way to
1699 * use the per cpu ftrace_stacks. We reserve it and if an interrupt
1700 * or NMI comes in, it will just have to use the default
1701 * FTRACE_STACK_SIZE.
1703 preempt_disable_notrace();
1705 use_stack
= __this_cpu_inc_return(ftrace_stack_reserve
);
1707 * We don't need any atomic variables, just a barrier.
1708 * If an interrupt comes in, we don't care, because it would
1709 * have exited and put the counter back to what we want.
1710 * We just need a barrier to keep gcc from moving things
1714 if (use_stack
== 1) {
1715 trace
.entries
= &__get_cpu_var(ftrace_stack
).calls
[0];
1716 trace
.max_entries
= FTRACE_STACK_MAX_ENTRIES
;
1719 save_stack_trace_regs(regs
, &trace
);
1721 save_stack_trace(&trace
);
1723 if (trace
.nr_entries
> size
)
1724 size
= trace
.nr_entries
;
1726 /* From now on, use_stack is a boolean */
1729 size
*= sizeof(unsigned long);
1731 event
= trace_buffer_lock_reserve(buffer
, TRACE_STACK
,
1732 sizeof(*entry
) + size
, flags
, pc
);
1735 entry
= ring_buffer_event_data(event
);
1737 memset(&entry
->caller
, 0, size
);
1740 memcpy(&entry
->caller
, trace
.entries
,
1741 trace
.nr_entries
* sizeof(unsigned long));
1743 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1744 trace
.entries
= entry
->caller
;
1746 save_stack_trace_regs(regs
, &trace
);
1748 save_stack_trace(&trace
);
1751 entry
->size
= trace
.nr_entries
;
1753 if (!call_filter_check_discard(call
, entry
, buffer
, event
))
1754 __buffer_unlock_commit(buffer
, event
);
1757 /* Again, don't let gcc optimize things here */
1759 __this_cpu_dec(ftrace_stack_reserve
);
1760 preempt_enable_notrace();
1764 void ftrace_trace_stack_regs(struct ring_buffer
*buffer
, unsigned long flags
,
1765 int skip
, int pc
, struct pt_regs
*regs
)
1767 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1770 __ftrace_trace_stack(buffer
, flags
, skip
, pc
, regs
);
1773 void ftrace_trace_stack(struct ring_buffer
*buffer
, unsigned long flags
,
1776 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1779 __ftrace_trace_stack(buffer
, flags
, skip
, pc
, NULL
);
1782 void __trace_stack(struct trace_array
*tr
, unsigned long flags
, int skip
,
1785 __ftrace_trace_stack(tr
->trace_buffer
.buffer
, flags
, skip
, pc
, NULL
);
1789 * trace_dump_stack - record a stack back trace in the trace buffer
1790 * @skip: Number of functions to skip (helper handlers)
1792 void trace_dump_stack(int skip
)
1794 unsigned long flags
;
1796 if (tracing_disabled
|| tracing_selftest_running
)
1799 local_save_flags(flags
);
1802 * Skip 3 more, seems to get us at the caller of
1806 __ftrace_trace_stack(global_trace
.trace_buffer
.buffer
,
1807 flags
, skip
, preempt_count(), NULL
);
1810 static DEFINE_PER_CPU(int, user_stack_count
);
1813 ftrace_trace_userstack(struct ring_buffer
*buffer
, unsigned long flags
, int pc
)
1815 struct ftrace_event_call
*call
= &event_user_stack
;
1816 struct ring_buffer_event
*event
;
1817 struct userstack_entry
*entry
;
1818 struct stack_trace trace
;
1820 if (!(trace_flags
& TRACE_ITER_USERSTACKTRACE
))
1824 * NMIs can not handle page faults, even with fix ups.
1825 * The save user stack can (and often does) fault.
1827 if (unlikely(in_nmi()))
1831 * prevent recursion, since the user stack tracing may
1832 * trigger other kernel events.
1835 if (__this_cpu_read(user_stack_count
))
1838 __this_cpu_inc(user_stack_count
);
1840 event
= trace_buffer_lock_reserve(buffer
, TRACE_USER_STACK
,
1841 sizeof(*entry
), flags
, pc
);
1843 goto out_drop_count
;
1844 entry
= ring_buffer_event_data(event
);
1846 entry
->tgid
= current
->tgid
;
1847 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
1849 trace
.nr_entries
= 0;
1850 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1852 trace
.entries
= entry
->caller
;
1854 save_stack_trace_user(&trace
);
1855 if (!call_filter_check_discard(call
, entry
, buffer
, event
))
1856 __buffer_unlock_commit(buffer
, event
);
1859 __this_cpu_dec(user_stack_count
);
1865 static void __trace_userstack(struct trace_array
*tr
, unsigned long flags
)
1867 ftrace_trace_userstack(tr
, flags
, preempt_count());
1871 #endif /* CONFIG_STACKTRACE */
1873 /* created for use with alloc_percpu */
1874 struct trace_buffer_struct
{
1875 char buffer
[TRACE_BUF_SIZE
];
1878 static struct trace_buffer_struct
*trace_percpu_buffer
;
1879 static struct trace_buffer_struct
*trace_percpu_sirq_buffer
;
1880 static struct trace_buffer_struct
*trace_percpu_irq_buffer
;
1881 static struct trace_buffer_struct
*trace_percpu_nmi_buffer
;
1884 * The buffer used is dependent on the context. There is a per cpu
1885 * buffer for normal context, softirq contex, hard irq context and
1886 * for NMI context. Thise allows for lockless recording.
1888 * Note, if the buffers failed to be allocated, then this returns NULL
1890 static char *get_trace_buf(void)
1892 struct trace_buffer_struct
*percpu_buffer
;
1895 * If we have allocated per cpu buffers, then we do not
1896 * need to do any locking.
1899 percpu_buffer
= trace_percpu_nmi_buffer
;
1901 percpu_buffer
= trace_percpu_irq_buffer
;
1902 else if (in_softirq())
1903 percpu_buffer
= trace_percpu_sirq_buffer
;
1905 percpu_buffer
= trace_percpu_buffer
;
1910 return this_cpu_ptr(&percpu_buffer
->buffer
[0]);
1913 static int alloc_percpu_trace_buffer(void)
1915 struct trace_buffer_struct
*buffers
;
1916 struct trace_buffer_struct
*sirq_buffers
;
1917 struct trace_buffer_struct
*irq_buffers
;
1918 struct trace_buffer_struct
*nmi_buffers
;
1920 buffers
= alloc_percpu(struct trace_buffer_struct
);
1924 sirq_buffers
= alloc_percpu(struct trace_buffer_struct
);
1928 irq_buffers
= alloc_percpu(struct trace_buffer_struct
);
1932 nmi_buffers
= alloc_percpu(struct trace_buffer_struct
);
1936 trace_percpu_buffer
= buffers
;
1937 trace_percpu_sirq_buffer
= sirq_buffers
;
1938 trace_percpu_irq_buffer
= irq_buffers
;
1939 trace_percpu_nmi_buffer
= nmi_buffers
;
1944 free_percpu(irq_buffers
);
1946 free_percpu(sirq_buffers
);
1948 free_percpu(buffers
);
1950 WARN(1, "Could not allocate percpu trace_printk buffer");
1954 static int buffers_allocated
;
1956 void trace_printk_init_buffers(void)
1958 if (buffers_allocated
)
1961 if (alloc_percpu_trace_buffer())
1964 pr_info("ftrace: Allocated trace_printk buffers\n");
1966 /* Expand the buffers to set size */
1967 tracing_update_buffers();
1969 buffers_allocated
= 1;
1972 * trace_printk_init_buffers() can be called by modules.
1973 * If that happens, then we need to start cmdline recording
1974 * directly here. If the global_trace.buffer is already
1975 * allocated here, then this was called by module code.
1977 if (global_trace
.trace_buffer
.buffer
)
1978 tracing_start_cmdline_record();
1981 void trace_printk_start_comm(void)
1983 /* Start tracing comms if trace printk is set */
1984 if (!buffers_allocated
)
1986 tracing_start_cmdline_record();
1989 static void trace_printk_start_stop_comm(int enabled
)
1991 if (!buffers_allocated
)
1995 tracing_start_cmdline_record();
1997 tracing_stop_cmdline_record();
2001 * trace_vbprintk - write binary msg to tracing buffer
2004 int trace_vbprintk(unsigned long ip
, const char *fmt
, va_list args
)
2006 struct ftrace_event_call
*call
= &event_bprint
;
2007 struct ring_buffer_event
*event
;
2008 struct ring_buffer
*buffer
;
2009 struct trace_array
*tr
= &global_trace
;
2010 struct bprint_entry
*entry
;
2011 unsigned long flags
;
2013 int len
= 0, size
, pc
;
2015 if (unlikely(tracing_selftest_running
|| tracing_disabled
))
2018 /* Don't pollute graph traces with trace_vprintk internals */
2019 pause_graph_tracing();
2021 pc
= preempt_count();
2022 preempt_disable_notrace();
2024 tbuffer
= get_trace_buf();
2030 len
= vbin_printf((u32
*)tbuffer
, TRACE_BUF_SIZE
/sizeof(int), fmt
, args
);
2032 if (len
> TRACE_BUF_SIZE
/sizeof(int) || len
< 0)
2035 local_save_flags(flags
);
2036 size
= sizeof(*entry
) + sizeof(u32
) * len
;
2037 buffer
= tr
->trace_buffer
.buffer
;
2038 event
= trace_buffer_lock_reserve(buffer
, TRACE_BPRINT
, size
,
2042 entry
= ring_buffer_event_data(event
);
2046 memcpy(entry
->buf
, tbuffer
, sizeof(u32
) * len
);
2047 if (!call_filter_check_discard(call
, entry
, buffer
, event
)) {
2048 __buffer_unlock_commit(buffer
, event
);
2049 ftrace_trace_stack(buffer
, flags
, 6, pc
);
2053 preempt_enable_notrace();
2054 unpause_graph_tracing();
2058 EXPORT_SYMBOL_GPL(trace_vbprintk
);
2061 __trace_array_vprintk(struct ring_buffer
*buffer
,
2062 unsigned long ip
, const char *fmt
, va_list args
)
2064 struct ftrace_event_call
*call
= &event_print
;
2065 struct ring_buffer_event
*event
;
2066 int len
= 0, size
, pc
;
2067 struct print_entry
*entry
;
2068 unsigned long flags
;
2071 if (tracing_disabled
|| tracing_selftest_running
)
2074 /* Don't pollute graph traces with trace_vprintk internals */
2075 pause_graph_tracing();
2077 pc
= preempt_count();
2078 preempt_disable_notrace();
2081 tbuffer
= get_trace_buf();
2087 len
= vsnprintf(tbuffer
, TRACE_BUF_SIZE
, fmt
, args
);
2088 if (len
> TRACE_BUF_SIZE
)
2091 local_save_flags(flags
);
2092 size
= sizeof(*entry
) + len
+ 1;
2093 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, size
,
2097 entry
= ring_buffer_event_data(event
);
2100 memcpy(&entry
->buf
, tbuffer
, len
);
2101 entry
->buf
[len
] = '\0';
2102 if (!call_filter_check_discard(call
, entry
, buffer
, event
)) {
2103 __buffer_unlock_commit(buffer
, event
);
2104 ftrace_trace_stack(buffer
, flags
, 6, pc
);
2107 preempt_enable_notrace();
2108 unpause_graph_tracing();
2113 int trace_array_vprintk(struct trace_array
*tr
,
2114 unsigned long ip
, const char *fmt
, va_list args
)
2116 return __trace_array_vprintk(tr
->trace_buffer
.buffer
, ip
, fmt
, args
);
2119 int trace_array_printk(struct trace_array
*tr
,
2120 unsigned long ip
, const char *fmt
, ...)
2125 if (!(trace_flags
& TRACE_ITER_PRINTK
))
2129 ret
= trace_array_vprintk(tr
, ip
, fmt
, ap
);
2134 int trace_array_printk_buf(struct ring_buffer
*buffer
,
2135 unsigned long ip
, const char *fmt
, ...)
2140 if (!(trace_flags
& TRACE_ITER_PRINTK
))
2144 ret
= __trace_array_vprintk(buffer
, ip
, fmt
, ap
);
2149 int trace_vprintk(unsigned long ip
, const char *fmt
, va_list args
)
2151 return trace_array_vprintk(&global_trace
, ip
, fmt
, args
);
2153 EXPORT_SYMBOL_GPL(trace_vprintk
);
2155 static void trace_iterator_increment(struct trace_iterator
*iter
)
2157 struct ring_buffer_iter
*buf_iter
= trace_buffer_iter(iter
, iter
->cpu
);
2161 ring_buffer_read(buf_iter
, NULL
);
2164 static struct trace_entry
*
2165 peek_next_entry(struct trace_iterator
*iter
, int cpu
, u64
*ts
,
2166 unsigned long *lost_events
)
2168 struct ring_buffer_event
*event
;
2169 struct ring_buffer_iter
*buf_iter
= trace_buffer_iter(iter
, cpu
);
2172 event
= ring_buffer_iter_peek(buf_iter
, ts
);
2174 event
= ring_buffer_peek(iter
->trace_buffer
->buffer
, cpu
, ts
,
2178 iter
->ent_size
= ring_buffer_event_length(event
);
2179 return ring_buffer_event_data(event
);
2185 static struct trace_entry
*
2186 __find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
,
2187 unsigned long *missing_events
, u64
*ent_ts
)
2189 struct ring_buffer
*buffer
= iter
->trace_buffer
->buffer
;
2190 struct trace_entry
*ent
, *next
= NULL
;
2191 unsigned long lost_events
= 0, next_lost
= 0;
2192 int cpu_file
= iter
->cpu_file
;
2193 u64 next_ts
= 0, ts
;
2199 * If we are in a per_cpu trace file, don't bother by iterating over
2200 * all cpu and peek directly.
2202 if (cpu_file
> RING_BUFFER_ALL_CPUS
) {
2203 if (ring_buffer_empty_cpu(buffer
, cpu_file
))
2205 ent
= peek_next_entry(iter
, cpu_file
, ent_ts
, missing_events
);
2207 *ent_cpu
= cpu_file
;
2212 for_each_tracing_cpu(cpu
) {
2214 if (ring_buffer_empty_cpu(buffer
, cpu
))
2217 ent
= peek_next_entry(iter
, cpu
, &ts
, &lost_events
);
2220 * Pick the entry with the smallest timestamp:
2222 if (ent
&& (!next
|| ts
< next_ts
)) {
2226 next_lost
= lost_events
;
2227 next_size
= iter
->ent_size
;
2231 iter
->ent_size
= next_size
;
2234 *ent_cpu
= next_cpu
;
2240 *missing_events
= next_lost
;
2245 /* Find the next real entry, without updating the iterator itself */
2246 struct trace_entry
*trace_find_next_entry(struct trace_iterator
*iter
,
2247 int *ent_cpu
, u64
*ent_ts
)
2249 return __find_next_entry(iter
, ent_cpu
, NULL
, ent_ts
);
2252 /* Find the next real entry, and increment the iterator to the next entry */
2253 void *trace_find_next_entry_inc(struct trace_iterator
*iter
)
2255 iter
->ent
= __find_next_entry(iter
, &iter
->cpu
,
2256 &iter
->lost_events
, &iter
->ts
);
2259 trace_iterator_increment(iter
);
2261 return iter
->ent
? iter
: NULL
;
2264 static void trace_consume(struct trace_iterator
*iter
)
2266 ring_buffer_consume(iter
->trace_buffer
->buffer
, iter
->cpu
, &iter
->ts
,
2267 &iter
->lost_events
);
2270 static void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
2272 struct trace_iterator
*iter
= m
->private;
2276 WARN_ON_ONCE(iter
->leftover
);
2280 /* can't go backwards */
2285 ent
= trace_find_next_entry_inc(iter
);
2289 while (ent
&& iter
->idx
< i
)
2290 ent
= trace_find_next_entry_inc(iter
);
2297 void tracing_iter_reset(struct trace_iterator
*iter
, int cpu
)
2299 struct ring_buffer_event
*event
;
2300 struct ring_buffer_iter
*buf_iter
;
2301 unsigned long entries
= 0;
2304 per_cpu_ptr(iter
->trace_buffer
->data
, cpu
)->skipped_entries
= 0;
2306 buf_iter
= trace_buffer_iter(iter
, cpu
);
2310 ring_buffer_iter_reset(buf_iter
);
2313 * We could have the case with the max latency tracers
2314 * that a reset never took place on a cpu. This is evident
2315 * by the timestamp being before the start of the buffer.
2317 while ((event
= ring_buffer_iter_peek(buf_iter
, &ts
))) {
2318 if (ts
>= iter
->trace_buffer
->time_start
)
2321 ring_buffer_read(buf_iter
, NULL
);
2324 per_cpu_ptr(iter
->trace_buffer
->data
, cpu
)->skipped_entries
= entries
;
2328 * The current tracer is copied to avoid a global locking
2331 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
2333 struct trace_iterator
*iter
= m
->private;
2334 struct trace_array
*tr
= iter
->tr
;
2335 int cpu_file
= iter
->cpu_file
;
2341 * copy the tracer to avoid using a global lock all around.
2342 * iter->trace is a copy of current_trace, the pointer to the
2343 * name may be used instead of a strcmp(), as iter->trace->name
2344 * will point to the same string as current_trace->name.
2346 mutex_lock(&trace_types_lock
);
2347 if (unlikely(tr
->current_trace
&& iter
->trace
->name
!= tr
->current_trace
->name
))
2348 *iter
->trace
= *tr
->current_trace
;
2349 mutex_unlock(&trace_types_lock
);
2351 #ifdef CONFIG_TRACER_MAX_TRACE
2352 if (iter
->snapshot
&& iter
->trace
->use_max_tr
)
2353 return ERR_PTR(-EBUSY
);
2356 if (!iter
->snapshot
)
2357 atomic_inc(&trace_record_cmdline_disabled
);
2359 if (*pos
!= iter
->pos
) {
2364 if (cpu_file
== RING_BUFFER_ALL_CPUS
) {
2365 for_each_tracing_cpu(cpu
)
2366 tracing_iter_reset(iter
, cpu
);
2368 tracing_iter_reset(iter
, cpu_file
);
2371 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
2376 * If we overflowed the seq_file before, then we want
2377 * to just reuse the trace_seq buffer again.
2383 p
= s_next(m
, p
, &l
);
2387 trace_event_read_lock();
2388 trace_access_lock(cpu_file
);
2392 static void s_stop(struct seq_file
*m
, void *p
)
2394 struct trace_iterator
*iter
= m
->private;
2396 #ifdef CONFIG_TRACER_MAX_TRACE
2397 if (iter
->snapshot
&& iter
->trace
->use_max_tr
)
2401 if (!iter
->snapshot
)
2402 atomic_dec(&trace_record_cmdline_disabled
);
2404 trace_access_unlock(iter
->cpu_file
);
2405 trace_event_read_unlock();
2409 get_total_entries(struct trace_buffer
*buf
,
2410 unsigned long *total
, unsigned long *entries
)
2412 unsigned long count
;
2418 for_each_tracing_cpu(cpu
) {
2419 count
= ring_buffer_entries_cpu(buf
->buffer
, cpu
);
2421 * If this buffer has skipped entries, then we hold all
2422 * entries for the trace and we need to ignore the
2423 * ones before the time stamp.
2425 if (per_cpu_ptr(buf
->data
, cpu
)->skipped_entries
) {
2426 count
-= per_cpu_ptr(buf
->data
, cpu
)->skipped_entries
;
2427 /* total is the same as the entries */
2431 ring_buffer_overrun_cpu(buf
->buffer
, cpu
);
2436 static void print_lat_help_header(struct seq_file
*m
)
2438 seq_puts(m
, "# _------=> CPU# \n");
2439 seq_puts(m
, "# / _-----=> irqs-off \n");
2440 seq_puts(m
, "# | / _----=> need-resched \n");
2441 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
2442 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
2443 seq_puts(m
, "# |||| / delay \n");
2444 seq_puts(m
, "# cmd pid ||||| time | caller \n");
2445 seq_puts(m
, "# \\ / ||||| \\ | / \n");
2448 static void print_event_info(struct trace_buffer
*buf
, struct seq_file
*m
)
2450 unsigned long total
;
2451 unsigned long entries
;
2453 get_total_entries(buf
, &total
, &entries
);
2454 seq_printf(m
, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
2455 entries
, total
, num_online_cpus());
2459 static void print_func_help_header(struct trace_buffer
*buf
, struct seq_file
*m
)
2461 print_event_info(buf
, m
);
2462 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
2463 seq_puts(m
, "# | | | | |\n");
2466 static void print_func_help_header_irq(struct trace_buffer
*buf
, struct seq_file
*m
)
2468 print_event_info(buf
, m
);
2469 seq_puts(m
, "# _-----=> irqs-off\n");
2470 seq_puts(m
, "# / _----=> need-resched\n");
2471 seq_puts(m
, "# | / _---=> hardirq/softirq\n");
2472 seq_puts(m
, "# || / _--=> preempt-depth\n");
2473 seq_puts(m
, "# ||| / delay\n");
2474 seq_puts(m
, "# TASK-PID CPU# |||| TIMESTAMP FUNCTION\n");
2475 seq_puts(m
, "# | | | |||| | |\n");
2479 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
2481 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
2482 struct trace_buffer
*buf
= iter
->trace_buffer
;
2483 struct trace_array_cpu
*data
= per_cpu_ptr(buf
->data
, buf
->cpu
);
2484 struct tracer
*type
= iter
->trace
;
2485 unsigned long entries
;
2486 unsigned long total
;
2487 const char *name
= "preemption";
2491 get_total_entries(buf
, &total
, &entries
);
2493 seq_printf(m
, "# %s latency trace v1.1.5 on %s\n",
2495 seq_puts(m
, "# -----------------------------------"
2496 "---------------------------------\n");
2497 seq_printf(m
, "# latency: %lu us, #%lu/%lu, CPU#%d |"
2498 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
2499 nsecs_to_usecs(data
->saved_latency
),
2503 #if defined(CONFIG_PREEMPT_NONE)
2505 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
2507 #elif defined(CONFIG_PREEMPT)
2512 /* These are reserved for later use */
2515 seq_printf(m
, " #P:%d)\n", num_online_cpus());
2519 seq_puts(m
, "# -----------------\n");
2520 seq_printf(m
, "# | task: %.16s-%d "
2521 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
2522 data
->comm
, data
->pid
,
2523 from_kuid_munged(seq_user_ns(m
), data
->uid
), data
->nice
,
2524 data
->policy
, data
->rt_priority
);
2525 seq_puts(m
, "# -----------------\n");
2527 if (data
->critical_start
) {
2528 seq_puts(m
, "# => started at: ");
2529 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
2530 trace_print_seq(m
, &iter
->seq
);
2531 seq_puts(m
, "\n# => ended at: ");
2532 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
2533 trace_print_seq(m
, &iter
->seq
);
2534 seq_puts(m
, "\n#\n");
2540 static void test_cpu_buff_start(struct trace_iterator
*iter
)
2542 struct trace_seq
*s
= &iter
->seq
;
2544 if (!(trace_flags
& TRACE_ITER_ANNOTATE
))
2547 if (!(iter
->iter_flags
& TRACE_FILE_ANNOTATE
))
2550 if (cpumask_test_cpu(iter
->cpu
, iter
->started
))
2553 if (per_cpu_ptr(iter
->trace_buffer
->data
, iter
->cpu
)->skipped_entries
)
2556 cpumask_set_cpu(iter
->cpu
, iter
->started
);
2558 /* Don't print started cpu buffer for the first entry of the trace */
2560 trace_seq_printf(s
, "##### CPU %u buffer started ####\n",
2564 static enum print_line_t
print_trace_fmt(struct trace_iterator
*iter
)
2566 struct trace_seq
*s
= &iter
->seq
;
2567 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
2568 struct trace_entry
*entry
;
2569 struct trace_event
*event
;
2573 test_cpu_buff_start(iter
);
2575 event
= ftrace_find_event(entry
->type
);
2577 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2578 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
2579 if (!trace_print_lat_context(iter
))
2582 if (!trace_print_context(iter
))
2588 return event
->funcs
->trace(iter
, sym_flags
, event
);
2590 if (!trace_seq_printf(s
, "Unknown type %d\n", entry
->type
))
2593 return TRACE_TYPE_HANDLED
;
2595 return TRACE_TYPE_PARTIAL_LINE
;
2598 static enum print_line_t
print_raw_fmt(struct trace_iterator
*iter
)
2600 struct trace_seq
*s
= &iter
->seq
;
2601 struct trace_entry
*entry
;
2602 struct trace_event
*event
;
2606 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2607 if (!trace_seq_printf(s
, "%d %d %llu ",
2608 entry
->pid
, iter
->cpu
, iter
->ts
))
2612 event
= ftrace_find_event(entry
->type
);
2614 return event
->funcs
->raw(iter
, 0, event
);
2616 if (!trace_seq_printf(s
, "%d ?\n", entry
->type
))
2619 return TRACE_TYPE_HANDLED
;
2621 return TRACE_TYPE_PARTIAL_LINE
;
2624 static enum print_line_t
print_hex_fmt(struct trace_iterator
*iter
)
2626 struct trace_seq
*s
= &iter
->seq
;
2627 unsigned char newline
= '\n';
2628 struct trace_entry
*entry
;
2629 struct trace_event
*event
;
2633 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2634 SEQ_PUT_HEX_FIELD_RET(s
, entry
->pid
);
2635 SEQ_PUT_HEX_FIELD_RET(s
, iter
->cpu
);
2636 SEQ_PUT_HEX_FIELD_RET(s
, iter
->ts
);
2639 event
= ftrace_find_event(entry
->type
);
2641 enum print_line_t ret
= event
->funcs
->hex(iter
, 0, event
);
2642 if (ret
!= TRACE_TYPE_HANDLED
)
2646 SEQ_PUT_FIELD_RET(s
, newline
);
2648 return TRACE_TYPE_HANDLED
;
2651 static enum print_line_t
print_bin_fmt(struct trace_iterator
*iter
)
2653 struct trace_seq
*s
= &iter
->seq
;
2654 struct trace_entry
*entry
;
2655 struct trace_event
*event
;
2659 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2660 SEQ_PUT_FIELD_RET(s
, entry
->pid
);
2661 SEQ_PUT_FIELD_RET(s
, iter
->cpu
);
2662 SEQ_PUT_FIELD_RET(s
, iter
->ts
);
2665 event
= ftrace_find_event(entry
->type
);
2666 return event
? event
->funcs
->binary(iter
, 0, event
) :
2670 int trace_empty(struct trace_iterator
*iter
)
2672 struct ring_buffer_iter
*buf_iter
;
2675 /* If we are looking at one CPU buffer, only check that one */
2676 if (iter
->cpu_file
!= RING_BUFFER_ALL_CPUS
) {
2677 cpu
= iter
->cpu_file
;
2678 buf_iter
= trace_buffer_iter(iter
, cpu
);
2680 if (!ring_buffer_iter_empty(buf_iter
))
2683 if (!ring_buffer_empty_cpu(iter
->trace_buffer
->buffer
, cpu
))
2689 for_each_tracing_cpu(cpu
) {
2690 buf_iter
= trace_buffer_iter(iter
, cpu
);
2692 if (!ring_buffer_iter_empty(buf_iter
))
2695 if (!ring_buffer_empty_cpu(iter
->trace_buffer
->buffer
, cpu
))
2703 /* Called with trace_event_read_lock() held. */
2704 enum print_line_t
print_trace_line(struct trace_iterator
*iter
)
2706 enum print_line_t ret
;
2708 if (iter
->lost_events
&&
2709 !trace_seq_printf(&iter
->seq
, "CPU:%d [LOST %lu EVENTS]\n",
2710 iter
->cpu
, iter
->lost_events
))
2711 return TRACE_TYPE_PARTIAL_LINE
;
2713 if (iter
->trace
&& iter
->trace
->print_line
) {
2714 ret
= iter
->trace
->print_line(iter
);
2715 if (ret
!= TRACE_TYPE_UNHANDLED
)
2719 if (iter
->ent
->type
== TRACE_BPUTS
&&
2720 trace_flags
& TRACE_ITER_PRINTK
&&
2721 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2722 return trace_print_bputs_msg_only(iter
);
2724 if (iter
->ent
->type
== TRACE_BPRINT
&&
2725 trace_flags
& TRACE_ITER_PRINTK
&&
2726 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2727 return trace_print_bprintk_msg_only(iter
);
2729 if (iter
->ent
->type
== TRACE_PRINT
&&
2730 trace_flags
& TRACE_ITER_PRINTK
&&
2731 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2732 return trace_print_printk_msg_only(iter
);
2734 if (trace_flags
& TRACE_ITER_BIN
)
2735 return print_bin_fmt(iter
);
2737 if (trace_flags
& TRACE_ITER_HEX
)
2738 return print_hex_fmt(iter
);
2740 if (trace_flags
& TRACE_ITER_RAW
)
2741 return print_raw_fmt(iter
);
2743 return print_trace_fmt(iter
);
2746 void trace_latency_header(struct seq_file
*m
)
2748 struct trace_iterator
*iter
= m
->private;
2750 /* print nothing if the buffers are empty */
2751 if (trace_empty(iter
))
2754 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
)
2755 print_trace_header(m
, iter
);
2757 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2758 print_lat_help_header(m
);
2761 void trace_default_header(struct seq_file
*m
)
2763 struct trace_iterator
*iter
= m
->private;
2765 if (!(trace_flags
& TRACE_ITER_CONTEXT_INFO
))
2768 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
2769 /* print nothing if the buffers are empty */
2770 if (trace_empty(iter
))
2772 print_trace_header(m
, iter
);
2773 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2774 print_lat_help_header(m
);
2776 if (!(trace_flags
& TRACE_ITER_VERBOSE
)) {
2777 if (trace_flags
& TRACE_ITER_IRQ_INFO
)
2778 print_func_help_header_irq(iter
->trace_buffer
, m
);
2780 print_func_help_header(iter
->trace_buffer
, m
);
2785 static void test_ftrace_alive(struct seq_file
*m
)
2787 if (!ftrace_is_dead())
2789 seq_printf(m
, "# WARNING: FUNCTION TRACING IS CORRUPTED\n");
2790 seq_printf(m
, "# MAY BE MISSING FUNCTION EVENTS\n");
2793 #ifdef CONFIG_TRACER_MAX_TRACE
2794 static void show_snapshot_main_help(struct seq_file
*m
)
2796 seq_printf(m
, "# echo 0 > snapshot : Clears and frees snapshot buffer\n");
2797 seq_printf(m
, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
2798 seq_printf(m
, "# Takes a snapshot of the main buffer.\n");
2799 seq_printf(m
, "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n");
2800 seq_printf(m
, "# (Doesn't have to be '2' works with any number that\n");
2801 seq_printf(m
, "# is not a '0' or '1')\n");
2804 static void show_snapshot_percpu_help(struct seq_file
*m
)
2806 seq_printf(m
, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
2807 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
2808 seq_printf(m
, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
2809 seq_printf(m
, "# Takes a snapshot of the main buffer for this cpu.\n");
2811 seq_printf(m
, "# echo 1 > snapshot : Not supported with this kernel.\n");
2812 seq_printf(m
, "# Must use main snapshot file to allocate.\n");
2814 seq_printf(m
, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n");
2815 seq_printf(m
, "# (Doesn't have to be '2' works with any number that\n");
2816 seq_printf(m
, "# is not a '0' or '1')\n");
2819 static void print_snapshot_help(struct seq_file
*m
, struct trace_iterator
*iter
)
2821 if (iter
->tr
->allocated_snapshot
)
2822 seq_printf(m
, "#\n# * Snapshot is allocated *\n#\n");
2824 seq_printf(m
, "#\n# * Snapshot is freed *\n#\n");
2826 seq_printf(m
, "# Snapshot commands:\n");
2827 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
)
2828 show_snapshot_main_help(m
);
2830 show_snapshot_percpu_help(m
);
2833 /* Should never be called */
2834 static inline void print_snapshot_help(struct seq_file
*m
, struct trace_iterator
*iter
) { }
2837 static int s_show(struct seq_file
*m
, void *v
)
2839 struct trace_iterator
*iter
= v
;
2842 if (iter
->ent
== NULL
) {
2844 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
2846 test_ftrace_alive(m
);
2848 if (iter
->snapshot
&& trace_empty(iter
))
2849 print_snapshot_help(m
, iter
);
2850 else if (iter
->trace
&& iter
->trace
->print_header
)
2851 iter
->trace
->print_header(m
);
2853 trace_default_header(m
);
2855 } else if (iter
->leftover
) {
2857 * If we filled the seq_file buffer earlier, we
2858 * want to just show it now.
2860 ret
= trace_print_seq(m
, &iter
->seq
);
2862 /* ret should this time be zero, but you never know */
2863 iter
->leftover
= ret
;
2866 print_trace_line(iter
);
2867 ret
= trace_print_seq(m
, &iter
->seq
);
2869 * If we overflow the seq_file buffer, then it will
2870 * ask us for this data again at start up.
2872 * ret is 0 if seq_file write succeeded.
2875 iter
->leftover
= ret
;
2882 * Should be used after trace_array_get(), trace_types_lock
2883 * ensures that i_cdev was already initialized.
2885 static inline int tracing_get_cpu(struct inode
*inode
)
2887 if (inode
->i_cdev
) /* See trace_create_cpu_file() */
2888 return (long)inode
->i_cdev
- 1;
2889 return RING_BUFFER_ALL_CPUS
;
2892 static const struct seq_operations tracer_seq_ops
= {
2899 static struct trace_iterator
*
2900 __tracing_open(struct inode
*inode
, struct file
*file
, bool snapshot
)
2902 struct trace_array
*tr
= inode
->i_private
;
2903 struct trace_iterator
*iter
;
2906 if (tracing_disabled
)
2907 return ERR_PTR(-ENODEV
);
2909 iter
= __seq_open_private(file
, &tracer_seq_ops
, sizeof(*iter
));
2911 return ERR_PTR(-ENOMEM
);
2913 iter
->buffer_iter
= kzalloc(sizeof(*iter
->buffer_iter
) * num_possible_cpus(),
2915 if (!iter
->buffer_iter
)
2919 * We make a copy of the current tracer to avoid concurrent
2920 * changes on it while we are reading.
2922 mutex_lock(&trace_types_lock
);
2923 iter
->trace
= kzalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
2927 *iter
->trace
= *tr
->current_trace
;
2929 if (!zalloc_cpumask_var(&iter
->started
, GFP_KERNEL
))
2934 #ifdef CONFIG_TRACER_MAX_TRACE
2935 /* Currently only the top directory has a snapshot */
2936 if (tr
->current_trace
->print_max
|| snapshot
)
2937 iter
->trace_buffer
= &tr
->max_buffer
;
2940 iter
->trace_buffer
= &tr
->trace_buffer
;
2941 iter
->snapshot
= snapshot
;
2943 iter
->cpu_file
= tracing_get_cpu(inode
);
2944 mutex_init(&iter
->mutex
);
2946 /* Notify the tracer early; before we stop tracing. */
2947 if (iter
->trace
&& iter
->trace
->open
)
2948 iter
->trace
->open(iter
);
2950 /* Annotate start of buffers if we had overruns */
2951 if (ring_buffer_overruns(iter
->trace_buffer
->buffer
))
2952 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
2954 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
2955 if (trace_clocks
[tr
->clock_id
].in_ns
)
2956 iter
->iter_flags
|= TRACE_FILE_TIME_IN_NS
;
2958 /* stop the trace while dumping if we are not opening "snapshot" */
2959 if (!iter
->snapshot
)
2960 tracing_stop_tr(tr
);
2962 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
) {
2963 for_each_tracing_cpu(cpu
) {
2964 iter
->buffer_iter
[cpu
] =
2965 ring_buffer_read_prepare(iter
->trace_buffer
->buffer
, cpu
);
2967 ring_buffer_read_prepare_sync();
2968 for_each_tracing_cpu(cpu
) {
2969 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2970 tracing_iter_reset(iter
, cpu
);
2973 cpu
= iter
->cpu_file
;
2974 iter
->buffer_iter
[cpu
] =
2975 ring_buffer_read_prepare(iter
->trace_buffer
->buffer
, cpu
);
2976 ring_buffer_read_prepare_sync();
2977 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2978 tracing_iter_reset(iter
, cpu
);
2981 mutex_unlock(&trace_types_lock
);
2986 mutex_unlock(&trace_types_lock
);
2988 kfree(iter
->buffer_iter
);
2990 seq_release_private(inode
, file
);
2991 return ERR_PTR(-ENOMEM
);
2994 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
2996 if (tracing_disabled
)
2999 filp
->private_data
= inode
->i_private
;
3003 bool tracing_is_disabled(void)
3005 return (tracing_disabled
) ? true: false;
3009 * Open and update trace_array ref count.
3010 * Must have the current trace_array passed to it.
3012 static int tracing_open_generic_tr(struct inode
*inode
, struct file
*filp
)
3014 struct trace_array
*tr
= inode
->i_private
;
3016 if (tracing_disabled
)
3019 if (trace_array_get(tr
) < 0)
3022 filp
->private_data
= inode
->i_private
;
3027 static int tracing_release(struct inode
*inode
, struct file
*file
)
3029 struct trace_array
*tr
= inode
->i_private
;
3030 struct seq_file
*m
= file
->private_data
;
3031 struct trace_iterator
*iter
;
3034 if (!(file
->f_mode
& FMODE_READ
)) {
3035 trace_array_put(tr
);
3039 /* Writes do not use seq_file */
3041 mutex_lock(&trace_types_lock
);
3043 for_each_tracing_cpu(cpu
) {
3044 if (iter
->buffer_iter
[cpu
])
3045 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
3048 if (iter
->trace
&& iter
->trace
->close
)
3049 iter
->trace
->close(iter
);
3051 if (!iter
->snapshot
)
3052 /* reenable tracing if it was previously enabled */
3053 tracing_start_tr(tr
);
3055 __trace_array_put(tr
);
3057 mutex_unlock(&trace_types_lock
);
3059 mutex_destroy(&iter
->mutex
);
3060 free_cpumask_var(iter
->started
);
3062 kfree(iter
->buffer_iter
);
3063 seq_release_private(inode
, file
);
3068 static int tracing_release_generic_tr(struct inode
*inode
, struct file
*file
)
3070 struct trace_array
*tr
= inode
->i_private
;
3072 trace_array_put(tr
);
3076 static int tracing_single_release_tr(struct inode
*inode
, struct file
*file
)
3078 struct trace_array
*tr
= inode
->i_private
;
3080 trace_array_put(tr
);
3082 return single_release(inode
, file
);
3085 static int tracing_open(struct inode
*inode
, struct file
*file
)
3087 struct trace_array
*tr
= inode
->i_private
;
3088 struct trace_iterator
*iter
;
3091 if (trace_array_get(tr
) < 0)
3094 /* If this file was open for write, then erase contents */
3095 if ((file
->f_mode
& FMODE_WRITE
) && (file
->f_flags
& O_TRUNC
)) {
3096 int cpu
= tracing_get_cpu(inode
);
3098 if (cpu
== RING_BUFFER_ALL_CPUS
)
3099 tracing_reset_online_cpus(&tr
->trace_buffer
);
3101 tracing_reset(&tr
->trace_buffer
, cpu
);
3104 if (file
->f_mode
& FMODE_READ
) {
3105 iter
= __tracing_open(inode
, file
, false);
3107 ret
= PTR_ERR(iter
);
3108 else if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
3109 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
3113 trace_array_put(tr
);
3119 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
3121 struct tracer
*t
= v
;
3131 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
3136 mutex_lock(&trace_types_lock
);
3137 for (t
= trace_types
; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
3143 static void t_stop(struct seq_file
*m
, void *p
)
3145 mutex_unlock(&trace_types_lock
);
3148 static int t_show(struct seq_file
*m
, void *v
)
3150 struct tracer
*t
= v
;
3155 seq_printf(m
, "%s", t
->name
);
3164 static const struct seq_operations show_traces_seq_ops
= {
3171 static int show_traces_open(struct inode
*inode
, struct file
*file
)
3173 if (tracing_disabled
)
3176 return seq_open(file
, &show_traces_seq_ops
);
3180 tracing_write_stub(struct file
*filp
, const char __user
*ubuf
,
3181 size_t count
, loff_t
*ppos
)
3186 loff_t
tracing_lseek(struct file
*file
, loff_t offset
, int whence
)
3190 if (file
->f_mode
& FMODE_READ
)
3191 ret
= seq_lseek(file
, offset
, whence
);
3193 file
->f_pos
= ret
= 0;
3198 static const struct file_operations tracing_fops
= {
3199 .open
= tracing_open
,
3201 .write
= tracing_write_stub
,
3202 .llseek
= tracing_lseek
,
3203 .release
= tracing_release
,
3206 static const struct file_operations show_traces_fops
= {
3207 .open
= show_traces_open
,
3209 .release
= seq_release
,
3210 .llseek
= seq_lseek
,
3214 * The tracer itself will not take this lock, but still we want
3215 * to provide a consistent cpumask to user-space:
3217 static DEFINE_MUTEX(tracing_cpumask_update_lock
);
3220 * Temporary storage for the character representation of the
3221 * CPU bitmask (and one more byte for the newline):
3223 static char mask_str
[NR_CPUS
+ 1];
3226 tracing_cpumask_read(struct file
*filp
, char __user
*ubuf
,
3227 size_t count
, loff_t
*ppos
)
3229 struct trace_array
*tr
= file_inode(filp
)->i_private
;
3232 mutex_lock(&tracing_cpumask_update_lock
);
3234 len
= cpumask_scnprintf(mask_str
, count
, tr
->tracing_cpumask
);
3235 if (count
- len
< 2) {
3239 len
+= sprintf(mask_str
+ len
, "\n");
3240 count
= simple_read_from_buffer(ubuf
, count
, ppos
, mask_str
, NR_CPUS
+1);
3243 mutex_unlock(&tracing_cpumask_update_lock
);
3249 tracing_cpumask_write(struct file
*filp
, const char __user
*ubuf
,
3250 size_t count
, loff_t
*ppos
)
3252 struct trace_array
*tr
= file_inode(filp
)->i_private
;
3253 cpumask_var_t tracing_cpumask_new
;
3256 if (!alloc_cpumask_var(&tracing_cpumask_new
, GFP_KERNEL
))
3259 err
= cpumask_parse_user(ubuf
, count
, tracing_cpumask_new
);
3263 mutex_lock(&tracing_cpumask_update_lock
);
3265 local_irq_disable();
3266 arch_spin_lock(&ftrace_max_lock
);
3267 for_each_tracing_cpu(cpu
) {
3269 * Increase/decrease the disabled counter if we are
3270 * about to flip a bit in the cpumask:
3272 if (cpumask_test_cpu(cpu
, tr
->tracing_cpumask
) &&
3273 !cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
3274 atomic_inc(&per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->disabled
);
3275 ring_buffer_record_disable_cpu(tr
->trace_buffer
.buffer
, cpu
);
3277 if (!cpumask_test_cpu(cpu
, tr
->tracing_cpumask
) &&
3278 cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
3279 atomic_dec(&per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->disabled
);
3280 ring_buffer_record_enable_cpu(tr
->trace_buffer
.buffer
, cpu
);
3283 arch_spin_unlock(&ftrace_max_lock
);
3286 cpumask_copy(tr
->tracing_cpumask
, tracing_cpumask_new
);
3288 mutex_unlock(&tracing_cpumask_update_lock
);
3289 free_cpumask_var(tracing_cpumask_new
);
3294 free_cpumask_var(tracing_cpumask_new
);
3299 static const struct file_operations tracing_cpumask_fops
= {
3300 .open
= tracing_open_generic_tr
,
3301 .read
= tracing_cpumask_read
,
3302 .write
= tracing_cpumask_write
,
3303 .release
= tracing_release_generic_tr
,
3304 .llseek
= generic_file_llseek
,
3307 static int tracing_trace_options_show(struct seq_file
*m
, void *v
)
3309 struct tracer_opt
*trace_opts
;
3310 struct trace_array
*tr
= m
->private;
3314 mutex_lock(&trace_types_lock
);
3315 tracer_flags
= tr
->current_trace
->flags
->val
;
3316 trace_opts
= tr
->current_trace
->flags
->opts
;
3318 for (i
= 0; trace_options
[i
]; i
++) {
3319 if (trace_flags
& (1 << i
))
3320 seq_printf(m
, "%s\n", trace_options
[i
]);
3322 seq_printf(m
, "no%s\n", trace_options
[i
]);
3325 for (i
= 0; trace_opts
[i
].name
; i
++) {
3326 if (tracer_flags
& trace_opts
[i
].bit
)
3327 seq_printf(m
, "%s\n", trace_opts
[i
].name
);
3329 seq_printf(m
, "no%s\n", trace_opts
[i
].name
);
3331 mutex_unlock(&trace_types_lock
);
3336 static int __set_tracer_option(struct tracer
*trace
,
3337 struct tracer_flags
*tracer_flags
,
3338 struct tracer_opt
*opts
, int neg
)
3342 ret
= trace
->set_flag(tracer_flags
->val
, opts
->bit
, !neg
);
3347 tracer_flags
->val
&= ~opts
->bit
;
3349 tracer_flags
->val
|= opts
->bit
;
3353 /* Try to assign a tracer specific option */
3354 static int set_tracer_option(struct tracer
*trace
, char *cmp
, int neg
)
3356 struct tracer_flags
*tracer_flags
= trace
->flags
;
3357 struct tracer_opt
*opts
= NULL
;
3360 for (i
= 0; tracer_flags
->opts
[i
].name
; i
++) {
3361 opts
= &tracer_flags
->opts
[i
];
3363 if (strcmp(cmp
, opts
->name
) == 0)
3364 return __set_tracer_option(trace
, trace
->flags
,
3371 /* Some tracers require overwrite to stay enabled */
3372 int trace_keep_overwrite(struct tracer
*tracer
, u32 mask
, int set
)
3374 if (tracer
->enabled
&& (mask
& TRACE_ITER_OVERWRITE
) && !set
)
3380 int set_tracer_flag(struct trace_array
*tr
, unsigned int mask
, int enabled
)
3382 /* do nothing if flag is already set */
3383 if (!!(trace_flags
& mask
) == !!enabled
)
3386 /* Give the tracer a chance to approve the change */
3387 if (tr
->current_trace
->flag_changed
)
3388 if (tr
->current_trace
->flag_changed(tr
->current_trace
, mask
, !!enabled
))
3392 trace_flags
|= mask
;
3394 trace_flags
&= ~mask
;
3396 if (mask
== TRACE_ITER_RECORD_CMD
)
3397 trace_event_enable_cmd_record(enabled
);
3399 if (mask
== TRACE_ITER_OVERWRITE
) {
3400 ring_buffer_change_overwrite(tr
->trace_buffer
.buffer
, enabled
);
3401 #ifdef CONFIG_TRACER_MAX_TRACE
3402 ring_buffer_change_overwrite(tr
->max_buffer
.buffer
, enabled
);
3406 if (mask
== TRACE_ITER_PRINTK
)
3407 trace_printk_start_stop_comm(enabled
);
3412 static int trace_set_options(struct trace_array
*tr
, char *option
)
3419 cmp
= strstrip(option
);
3421 if (strncmp(cmp
, "no", 2) == 0) {
3426 mutex_lock(&trace_types_lock
);
3428 for (i
= 0; trace_options
[i
]; i
++) {
3429 if (strcmp(cmp
, trace_options
[i
]) == 0) {
3430 ret
= set_tracer_flag(tr
, 1 << i
, !neg
);
3435 /* If no option could be set, test the specific tracer options */
3436 if (!trace_options
[i
])
3437 ret
= set_tracer_option(tr
->current_trace
, cmp
, neg
);
3439 mutex_unlock(&trace_types_lock
);
3445 tracing_trace_options_write(struct file
*filp
, const char __user
*ubuf
,
3446 size_t cnt
, loff_t
*ppos
)
3448 struct seq_file
*m
= filp
->private_data
;
3449 struct trace_array
*tr
= m
->private;
3453 if (cnt
>= sizeof(buf
))
3456 if (copy_from_user(&buf
, ubuf
, cnt
))
3461 ret
= trace_set_options(tr
, buf
);
3470 static int tracing_trace_options_open(struct inode
*inode
, struct file
*file
)
3472 struct trace_array
*tr
= inode
->i_private
;
3475 if (tracing_disabled
)
3478 if (trace_array_get(tr
) < 0)
3481 ret
= single_open(file
, tracing_trace_options_show
, inode
->i_private
);
3483 trace_array_put(tr
);
3488 static const struct file_operations tracing_iter_fops
= {
3489 .open
= tracing_trace_options_open
,
3491 .llseek
= seq_lseek
,
3492 .release
= tracing_single_release_tr
,
3493 .write
= tracing_trace_options_write
,
3496 static const char readme_msg
[] =
3497 "tracing mini-HOWTO:\n\n"
3498 "# echo 0 > tracing_on : quick way to disable tracing\n"
3499 "# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
3500 " Important files:\n"
3501 " trace\t\t\t- The static contents of the buffer\n"
3502 "\t\t\t To clear the buffer write into this file: echo > trace\n"
3503 " trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
3504 " current_tracer\t- function and latency tracers\n"
3505 " available_tracers\t- list of configured tracers for current_tracer\n"
3506 " buffer_size_kb\t- view and modify size of per cpu buffer\n"
3507 " buffer_total_size_kb - view total size of all cpu buffers\n\n"
3508 " trace_clock\t\t-change the clock used to order events\n"
3509 " local: Per cpu clock but may not be synced across CPUs\n"
3510 " global: Synced across CPUs but slows tracing down.\n"
3511 " counter: Not a clock, but just an increment\n"
3512 " uptime: Jiffy counter from time of boot\n"
3513 " perf: Same clock that perf events use\n"
3514 #ifdef CONFIG_X86_64
3515 " x86-tsc: TSC cycle counter\n"
3517 "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
3518 " tracing_cpumask\t- Limit which CPUs to trace\n"
3519 " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
3520 "\t\t\t Remove sub-buffer with rmdir\n"
3521 " trace_options\t\t- Set format or modify how tracing happens\n"
3522 "\t\t\t Disable an option by adding a suffix 'no' to the option name\n"
3523 #ifdef CONFIG_DYNAMIC_FTRACE
3524 "\n available_filter_functions - list of functions that can be filtered on\n"
3525 " set_ftrace_filter\t- echo function name in here to only trace these functions\n"
3526 " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3527 " modules: Can select a group via module\n"
3528 " Format: :mod:<module-name>\n"
3529 " example: echo :mod:ext3 > set_ftrace_filter\n"
3530 " triggers: a command to perform when function is hit\n"
3531 " Format: <function>:<trigger>[:count]\n"
3532 " trigger: traceon, traceoff\n"
3533 " enable_event:<system>:<event>\n"
3534 " disable_event:<system>:<event>\n"
3535 #ifdef CONFIG_STACKTRACE
3538 #ifdef CONFIG_TRACER_SNAPSHOT
3541 " example: echo do_fault:traceoff > set_ftrace_filter\n"
3542 " echo do_trap:traceoff:3 > set_ftrace_filter\n"
3543 " The first one will disable tracing every time do_fault is hit\n"
3544 " The second will disable tracing at most 3 times when do_trap is hit\n"
3545 " The first time do trap is hit and it disables tracing, the counter\n"
3546 " will decrement to 2. If tracing is already disabled, the counter\n"
3547 " will not decrement. It only decrements when the trigger did work\n"
3548 " To remove trigger without count:\n"
3549 " echo '!<function>:<trigger> > set_ftrace_filter\n"
3550 " To remove trigger with a count:\n"
3551 " echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
3552 " set_ftrace_notrace\t- echo function name in here to never trace.\n"
3553 " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3554 " modules: Can select a group via module command :mod:\n"
3555 " Does not accept triggers\n"
3556 #endif /* CONFIG_DYNAMIC_FTRACE */
3557 #ifdef CONFIG_FUNCTION_TRACER
3558 " set_ftrace_pid\t- Write pid(s) to only function trace those pids (function)\n"
3560 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3561 " set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
3562 " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
3564 #ifdef CONFIG_TRACER_SNAPSHOT
3565 "\n snapshot\t\t- Like 'trace' but shows the content of the static snapshot buffer\n"
3566 "\t\t\t Read the contents for more information\n"
3568 #ifdef CONFIG_STACK_TRACER
3569 " stack_trace\t\t- Shows the max stack trace when active\n"
3570 " stack_max_size\t- Shows current max stack size that was traced\n"
3571 "\t\t\t Write into this file to reset the max size (trigger a new trace)\n"
3572 #ifdef CONFIG_DYNAMIC_FTRACE
3573 " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace traces\n"
3575 #endif /* CONFIG_STACK_TRACER */
3576 " events/\t\t- Directory containing all trace event subsystems:\n"
3577 " enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
3578 " events/<system>/\t- Directory containing all trace events for <system>:\n"
3579 " enable\t\t- Write 0/1 to enable/disable tracing of all <system> events\n"
3580 " filter\t\t- If set, only events passing filter are traced\n"
3581 " events/<system>/<event>/\t- Directory containing control files for <event>:\n"
3582 " enable\t\t- Write 0/1 to enable/disable tracing of <event>\n"
3583 " filter\t\t- If set, only events passing filter are traced\n"
3584 " trigger\t\t- If set, a command to perform when event is hit\n"
3585 " Format: <trigger>[:count][if <filter>]\n"
3586 " trigger: traceon, traceoff\n"
3587 " enable_event:<system>:<event>\n"
3588 " disable_event:<system>:<event>\n"
3589 #ifdef CONFIG_STACKTRACE
3592 #ifdef CONFIG_TRACER_SNAPSHOT
3595 " example: echo traceoff > events/block/block_unplug/trigger\n"
3596 " echo traceoff:3 > events/block/block_unplug/trigger\n"
3597 " echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > events/block/block_unplug/trigger\n"
3598 " The first disables tracing every time block_unplug is hit.\n"
3599 " The second disables tracing the first 3 times block_unplug is hit.\n"
3600 " The third enables the kmalloc event the first 3 times block_unplug\n"
3601 " is hit and has value of greater than 1 for the 'nr_rq' event field.\n"
3602 " To remove a trigger without a count:\n"
3603 " echo '!<trigger> > <system>/<event>/trigger\n"
3604 " To remove a trigger with a count:\n"
3605 " echo '!<trigger>:0 > <system>/<event>/trigger\n"
3606 " Filters can be ignored when removing a trigger.\n"
3610 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
3611 size_t cnt
, loff_t
*ppos
)
3613 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
3614 readme_msg
, strlen(readme_msg
));
3617 static const struct file_operations tracing_readme_fops
= {
3618 .open
= tracing_open_generic
,
3619 .read
= tracing_readme_read
,
3620 .llseek
= generic_file_llseek
,
3624 tracing_saved_cmdlines_read(struct file
*file
, char __user
*ubuf
,
3625 size_t cnt
, loff_t
*ppos
)
3634 file_buf
= kmalloc(SAVED_CMDLINES
*(16+TASK_COMM_LEN
), GFP_KERNEL
);
3638 buf_comm
= kmalloc(TASK_COMM_LEN
, GFP_KERNEL
);
3646 for (i
= 0; i
< SAVED_CMDLINES
; i
++) {
3649 pid
= map_cmdline_to_pid
[i
];
3650 if (pid
== -1 || pid
== NO_CMDLINE_MAP
)
3653 trace_find_cmdline(pid
, buf_comm
);
3654 r
= sprintf(buf
, "%d %s\n", pid
, buf_comm
);
3659 len
= simple_read_from_buffer(ubuf
, cnt
, ppos
,
3668 static const struct file_operations tracing_saved_cmdlines_fops
= {
3669 .open
= tracing_open_generic
,
3670 .read
= tracing_saved_cmdlines_read
,
3671 .llseek
= generic_file_llseek
,
3675 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
3676 size_t cnt
, loff_t
*ppos
)
3678 struct trace_array
*tr
= filp
->private_data
;
3679 char buf
[MAX_TRACER_SIZE
+2];
3682 mutex_lock(&trace_types_lock
);
3683 r
= sprintf(buf
, "%s\n", tr
->current_trace
->name
);
3684 mutex_unlock(&trace_types_lock
);
3686 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3689 int tracer_init(struct tracer
*t
, struct trace_array
*tr
)
3691 tracing_reset_online_cpus(&tr
->trace_buffer
);
3695 static void set_buffer_entries(struct trace_buffer
*buf
, unsigned long val
)
3699 for_each_tracing_cpu(cpu
)
3700 per_cpu_ptr(buf
->data
, cpu
)->entries
= val
;
3703 #ifdef CONFIG_TRACER_MAX_TRACE
3704 /* resize @tr's buffer to the size of @size_tr's entries */
3705 static int resize_buffer_duplicate_size(struct trace_buffer
*trace_buf
,
3706 struct trace_buffer
*size_buf
, int cpu_id
)
3710 if (cpu_id
== RING_BUFFER_ALL_CPUS
) {
3711 for_each_tracing_cpu(cpu
) {
3712 ret
= ring_buffer_resize(trace_buf
->buffer
,
3713 per_cpu_ptr(size_buf
->data
, cpu
)->entries
, cpu
);
3716 per_cpu_ptr(trace_buf
->data
, cpu
)->entries
=
3717 per_cpu_ptr(size_buf
->data
, cpu
)->entries
;
3720 ret
= ring_buffer_resize(trace_buf
->buffer
,
3721 per_cpu_ptr(size_buf
->data
, cpu_id
)->entries
, cpu_id
);
3723 per_cpu_ptr(trace_buf
->data
, cpu_id
)->entries
=
3724 per_cpu_ptr(size_buf
->data
, cpu_id
)->entries
;
3729 #endif /* CONFIG_TRACER_MAX_TRACE */
3731 static int __tracing_resize_ring_buffer(struct trace_array
*tr
,
3732 unsigned long size
, int cpu
)
3737 * If kernel or user changes the size of the ring buffer
3738 * we use the size that was given, and we can forget about
3739 * expanding it later.
3741 ring_buffer_expanded
= true;
3743 /* May be called before buffers are initialized */
3744 if (!tr
->trace_buffer
.buffer
)
3747 ret
= ring_buffer_resize(tr
->trace_buffer
.buffer
, size
, cpu
);
3751 #ifdef CONFIG_TRACER_MAX_TRACE
3752 if (!(tr
->flags
& TRACE_ARRAY_FL_GLOBAL
) ||
3753 !tr
->current_trace
->use_max_tr
)
3756 ret
= ring_buffer_resize(tr
->max_buffer
.buffer
, size
, cpu
);
3758 int r
= resize_buffer_duplicate_size(&tr
->trace_buffer
,
3759 &tr
->trace_buffer
, cpu
);
3762 * AARGH! We are left with different
3763 * size max buffer!!!!
3764 * The max buffer is our "snapshot" buffer.
3765 * When a tracer needs a snapshot (one of the
3766 * latency tracers), it swaps the max buffer
3767 * with the saved snap shot. We succeeded to
3768 * update the size of the main buffer, but failed to
3769 * update the size of the max buffer. But when we tried
3770 * to reset the main buffer to the original size, we
3771 * failed there too. This is very unlikely to
3772 * happen, but if it does, warn and kill all
3776 tracing_disabled
= 1;
3781 if (cpu
== RING_BUFFER_ALL_CPUS
)
3782 set_buffer_entries(&tr
->max_buffer
, size
);
3784 per_cpu_ptr(tr
->max_buffer
.data
, cpu
)->entries
= size
;
3787 #endif /* CONFIG_TRACER_MAX_TRACE */
3789 if (cpu
== RING_BUFFER_ALL_CPUS
)
3790 set_buffer_entries(&tr
->trace_buffer
, size
);
3792 per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
= size
;
3797 static ssize_t
tracing_resize_ring_buffer(struct trace_array
*tr
,
3798 unsigned long size
, int cpu_id
)
3802 mutex_lock(&trace_types_lock
);
3804 if (cpu_id
!= RING_BUFFER_ALL_CPUS
) {
3805 /* make sure, this cpu is enabled in the mask */
3806 if (!cpumask_test_cpu(cpu_id
, tracing_buffer_mask
)) {
3812 ret
= __tracing_resize_ring_buffer(tr
, size
, cpu_id
);
3817 mutex_unlock(&trace_types_lock
);
3824 * tracing_update_buffers - used by tracing facility to expand ring buffers
3826 * To save on memory when the tracing is never used on a system with it
3827 * configured in. The ring buffers are set to a minimum size. But once
3828 * a user starts to use the tracing facility, then they need to grow
3829 * to their default size.
3831 * This function is to be called when a tracer is about to be used.
3833 int tracing_update_buffers(void)
3837 mutex_lock(&trace_types_lock
);
3838 if (!ring_buffer_expanded
)
3839 ret
= __tracing_resize_ring_buffer(&global_trace
, trace_buf_size
,
3840 RING_BUFFER_ALL_CPUS
);
3841 mutex_unlock(&trace_types_lock
);
3846 struct trace_option_dentry
;
3848 static struct trace_option_dentry
*
3849 create_trace_option_files(struct trace_array
*tr
, struct tracer
*tracer
);
3852 destroy_trace_option_files(struct trace_option_dentry
*topts
);
3854 static int tracing_set_tracer(const char *buf
)
3856 static struct trace_option_dentry
*topts
;
3857 struct trace_array
*tr
= &global_trace
;
3859 #ifdef CONFIG_TRACER_MAX_TRACE
3864 mutex_lock(&trace_types_lock
);
3866 if (!ring_buffer_expanded
) {
3867 ret
= __tracing_resize_ring_buffer(tr
, trace_buf_size
,
3868 RING_BUFFER_ALL_CPUS
);
3874 for (t
= trace_types
; t
; t
= t
->next
) {
3875 if (strcmp(t
->name
, buf
) == 0)
3882 if (t
== tr
->current_trace
)
3885 trace_branch_disable();
3887 tr
->current_trace
->enabled
= false;
3889 if (tr
->current_trace
->reset
)
3890 tr
->current_trace
->reset(tr
);
3892 /* Current trace needs to be nop_trace before synchronize_sched */
3893 tr
->current_trace
= &nop_trace
;
3895 #ifdef CONFIG_TRACER_MAX_TRACE
3896 had_max_tr
= tr
->allocated_snapshot
;
3898 if (had_max_tr
&& !t
->use_max_tr
) {
3900 * We need to make sure that the update_max_tr sees that
3901 * current_trace changed to nop_trace to keep it from
3902 * swapping the buffers after we resize it.
3903 * The update_max_tr is called from interrupts disabled
3904 * so a synchronized_sched() is sufficient.
3906 synchronize_sched();
3910 destroy_trace_option_files(topts
);
3912 topts
= create_trace_option_files(tr
, t
);
3914 #ifdef CONFIG_TRACER_MAX_TRACE
3915 if (t
->use_max_tr
&& !had_max_tr
) {
3916 ret
= alloc_snapshot(tr
);
3923 ret
= tracer_init(t
, tr
);
3928 tr
->current_trace
= t
;
3929 tr
->current_trace
->enabled
= true;
3930 trace_branch_enable(tr
);
3932 mutex_unlock(&trace_types_lock
);
3938 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
3939 size_t cnt
, loff_t
*ppos
)
3941 char buf
[MAX_TRACER_SIZE
+1];
3948 if (cnt
> MAX_TRACER_SIZE
)
3949 cnt
= MAX_TRACER_SIZE
;
3951 if (copy_from_user(&buf
, ubuf
, cnt
))
3956 /* strip ending whitespace. */
3957 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
3960 err
= tracing_set_tracer(buf
);
3970 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
3971 size_t cnt
, loff_t
*ppos
)
3973 unsigned long *ptr
= filp
->private_data
;
3977 r
= snprintf(buf
, sizeof(buf
), "%ld\n",
3978 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
3979 if (r
> sizeof(buf
))
3981 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3985 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
3986 size_t cnt
, loff_t
*ppos
)
3988 unsigned long *ptr
= filp
->private_data
;
3992 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
4001 static int tracing_open_pipe(struct inode
*inode
, struct file
*filp
)
4003 struct trace_array
*tr
= inode
->i_private
;
4004 struct trace_iterator
*iter
;
4007 if (tracing_disabled
)
4010 if (trace_array_get(tr
) < 0)
4013 mutex_lock(&trace_types_lock
);
4015 /* create a buffer to store the information to pass to userspace */
4016 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
4019 __trace_array_put(tr
);
4024 * We make a copy of the current tracer to avoid concurrent
4025 * changes on it while we are reading.
4027 iter
->trace
= kmalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
4032 *iter
->trace
= *tr
->current_trace
;
4034 if (!alloc_cpumask_var(&iter
->started
, GFP_KERNEL
)) {
4039 /* trace pipe does not show start of buffer */
4040 cpumask_setall(iter
->started
);
4042 if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
4043 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
4045 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
4046 if (trace_clocks
[tr
->clock_id
].in_ns
)
4047 iter
->iter_flags
|= TRACE_FILE_TIME_IN_NS
;
4050 iter
->trace_buffer
= &tr
->trace_buffer
;
4051 iter
->cpu_file
= tracing_get_cpu(inode
);
4052 mutex_init(&iter
->mutex
);
4053 filp
->private_data
= iter
;
4055 if (iter
->trace
->pipe_open
)
4056 iter
->trace
->pipe_open(iter
);
4058 nonseekable_open(inode
, filp
);
4060 mutex_unlock(&trace_types_lock
);
4066 __trace_array_put(tr
);
4067 mutex_unlock(&trace_types_lock
);
4071 static int tracing_release_pipe(struct inode
*inode
, struct file
*file
)
4073 struct trace_iterator
*iter
= file
->private_data
;
4074 struct trace_array
*tr
= inode
->i_private
;
4076 mutex_lock(&trace_types_lock
);
4078 if (iter
->trace
->pipe_close
)
4079 iter
->trace
->pipe_close(iter
);
4081 mutex_unlock(&trace_types_lock
);
4083 free_cpumask_var(iter
->started
);
4084 mutex_destroy(&iter
->mutex
);
4088 trace_array_put(tr
);
4094 trace_poll(struct trace_iterator
*iter
, struct file
*filp
, poll_table
*poll_table
)
4096 /* Iterators are static, they should be filled or empty */
4097 if (trace_buffer_iter(iter
, iter
->cpu_file
))
4098 return POLLIN
| POLLRDNORM
;
4100 if (trace_flags
& TRACE_ITER_BLOCK
)
4102 * Always select as readable when in blocking mode
4104 return POLLIN
| POLLRDNORM
;
4106 return ring_buffer_poll_wait(iter
->trace_buffer
->buffer
, iter
->cpu_file
,
4111 tracing_poll_pipe(struct file
*filp
, poll_table
*poll_table
)
4113 struct trace_iterator
*iter
= filp
->private_data
;
4115 return trace_poll(iter
, filp
, poll_table
);
4119 * This is a make-shift waitqueue.
4120 * A tracer might use this callback on some rare cases:
4122 * 1) the current tracer might hold the runqueue lock when it wakes up
4123 * a reader, hence a deadlock (sched, function, and function graph tracers)
4124 * 2) the function tracers, trace all functions, we don't want
4125 * the overhead of calling wake_up and friends
4126 * (and tracing them too)
4128 * Anyway, this is really very primitive wakeup.
4130 void poll_wait_pipe(struct trace_iterator
*iter
)
4132 set_current_state(TASK_INTERRUPTIBLE
);
4133 /* sleep for 100 msecs, and try again. */
4134 schedule_timeout(HZ
/ 10);
4137 /* Must be called with trace_types_lock mutex held. */
4138 static int tracing_wait_pipe(struct file
*filp
)
4140 struct trace_iterator
*iter
= filp
->private_data
;
4142 while (trace_empty(iter
)) {
4144 if ((filp
->f_flags
& O_NONBLOCK
)) {
4148 mutex_unlock(&iter
->mutex
);
4150 iter
->trace
->wait_pipe(iter
);
4152 mutex_lock(&iter
->mutex
);
4154 if (signal_pending(current
))
4158 * We block until we read something and tracing is disabled.
4159 * We still block if tracing is disabled, but we have never
4160 * read anything. This allows a user to cat this file, and
4161 * then enable tracing. But after we have read something,
4162 * we give an EOF when tracing is again disabled.
4164 * iter->pos will be 0 if we haven't read anything.
4166 if (!tracing_is_on() && iter
->pos
)
4177 tracing_read_pipe(struct file
*filp
, char __user
*ubuf
,
4178 size_t cnt
, loff_t
*ppos
)
4180 struct trace_iterator
*iter
= filp
->private_data
;
4181 struct trace_array
*tr
= iter
->tr
;
4184 /* return any leftover data */
4185 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
4189 trace_seq_init(&iter
->seq
);
4191 /* copy the tracer to avoid using a global lock all around */
4192 mutex_lock(&trace_types_lock
);
4193 if (unlikely(iter
->trace
->name
!= tr
->current_trace
->name
))
4194 *iter
->trace
= *tr
->current_trace
;
4195 mutex_unlock(&trace_types_lock
);
4198 * Avoid more than one consumer on a single file descriptor
4199 * This is just a matter of traces coherency, the ring buffer itself
4202 mutex_lock(&iter
->mutex
);
4203 if (iter
->trace
->read
) {
4204 sret
= iter
->trace
->read(iter
, filp
, ubuf
, cnt
, ppos
);
4210 sret
= tracing_wait_pipe(filp
);
4214 /* stop when tracing is finished */
4215 if (trace_empty(iter
)) {
4220 if (cnt
>= PAGE_SIZE
)
4221 cnt
= PAGE_SIZE
- 1;
4223 /* reset all but tr, trace, and overruns */
4224 memset(&iter
->seq
, 0,
4225 sizeof(struct trace_iterator
) -
4226 offsetof(struct trace_iterator
, seq
));
4227 cpumask_clear(iter
->started
);
4230 trace_event_read_lock();
4231 trace_access_lock(iter
->cpu_file
);
4232 while (trace_find_next_entry_inc(iter
) != NULL
) {
4233 enum print_line_t ret
;
4234 int len
= iter
->seq
.len
;
4236 ret
= print_trace_line(iter
);
4237 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
4238 /* don't print partial lines */
4239 iter
->seq
.len
= len
;
4242 if (ret
!= TRACE_TYPE_NO_CONSUME
)
4243 trace_consume(iter
);
4245 if (iter
->seq
.len
>= cnt
)
4249 * Setting the full flag means we reached the trace_seq buffer
4250 * size and we should leave by partial output condition above.
4251 * One of the trace_seq_* functions is not used properly.
4253 WARN_ONCE(iter
->seq
.full
, "full flag set for trace type %d",
4256 trace_access_unlock(iter
->cpu_file
);
4257 trace_event_read_unlock();
4259 /* Now copy what we have to the user */
4260 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
4261 if (iter
->seq
.readpos
>= iter
->seq
.len
)
4262 trace_seq_init(&iter
->seq
);
4265 * If there was nothing to send to user, in spite of consuming trace
4266 * entries, go back to wait for more entries.
4272 mutex_unlock(&iter
->mutex
);
4277 static void tracing_spd_release_pipe(struct splice_pipe_desc
*spd
,
4280 __free_page(spd
->pages
[idx
]);
4283 static const struct pipe_buf_operations tracing_pipe_buf_ops
= {
4285 .map
= generic_pipe_buf_map
,
4286 .unmap
= generic_pipe_buf_unmap
,
4287 .confirm
= generic_pipe_buf_confirm
,
4288 .release
= generic_pipe_buf_release
,
4289 .steal
= generic_pipe_buf_steal
,
4290 .get
= generic_pipe_buf_get
,
4294 tracing_fill_pipe_page(size_t rem
, struct trace_iterator
*iter
)
4299 /* Seq buffer is page-sized, exactly what we need. */
4301 count
= iter
->seq
.len
;
4302 ret
= print_trace_line(iter
);
4303 count
= iter
->seq
.len
- count
;
4306 iter
->seq
.len
-= count
;
4309 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
4310 iter
->seq
.len
-= count
;
4314 if (ret
!= TRACE_TYPE_NO_CONSUME
)
4315 trace_consume(iter
);
4317 if (!trace_find_next_entry_inc(iter
)) {
4327 static ssize_t
tracing_splice_read_pipe(struct file
*filp
,
4329 struct pipe_inode_info
*pipe
,
4333 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
4334 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
4335 struct trace_iterator
*iter
= filp
->private_data
;
4336 struct splice_pipe_desc spd
= {
4338 .partial
= partial_def
,
4339 .nr_pages
= 0, /* This gets updated below. */
4340 .nr_pages_max
= PIPE_DEF_BUFFERS
,
4342 .ops
= &tracing_pipe_buf_ops
,
4343 .spd_release
= tracing_spd_release_pipe
,
4345 struct trace_array
*tr
= iter
->tr
;
4350 if (splice_grow_spd(pipe
, &spd
))
4353 /* copy the tracer to avoid using a global lock all around */
4354 mutex_lock(&trace_types_lock
);
4355 if (unlikely(iter
->trace
->name
!= tr
->current_trace
->name
))
4356 *iter
->trace
= *tr
->current_trace
;
4357 mutex_unlock(&trace_types_lock
);
4359 mutex_lock(&iter
->mutex
);
4361 if (iter
->trace
->splice_read
) {
4362 ret
= iter
->trace
->splice_read(iter
, filp
,
4363 ppos
, pipe
, len
, flags
);
4368 ret
= tracing_wait_pipe(filp
);
4372 if (!iter
->ent
&& !trace_find_next_entry_inc(iter
)) {
4377 trace_event_read_lock();
4378 trace_access_lock(iter
->cpu_file
);
4380 /* Fill as many pages as possible. */
4381 for (i
= 0, rem
= len
; i
< pipe
->buffers
&& rem
; i
++) {
4382 spd
.pages
[i
] = alloc_page(GFP_KERNEL
);
4386 rem
= tracing_fill_pipe_page(rem
, iter
);
4388 /* Copy the data into the page, so we can start over. */
4389 ret
= trace_seq_to_buffer(&iter
->seq
,
4390 page_address(spd
.pages
[i
]),
4393 __free_page(spd
.pages
[i
]);
4396 spd
.partial
[i
].offset
= 0;
4397 spd
.partial
[i
].len
= iter
->seq
.len
;
4399 trace_seq_init(&iter
->seq
);
4402 trace_access_unlock(iter
->cpu_file
);
4403 trace_event_read_unlock();
4404 mutex_unlock(&iter
->mutex
);
4408 ret
= splice_to_pipe(pipe
, &spd
);
4410 splice_shrink_spd(&spd
);
4414 mutex_unlock(&iter
->mutex
);
4419 tracing_entries_read(struct file
*filp
, char __user
*ubuf
,
4420 size_t cnt
, loff_t
*ppos
)
4422 struct inode
*inode
= file_inode(filp
);
4423 struct trace_array
*tr
= inode
->i_private
;
4424 int cpu
= tracing_get_cpu(inode
);
4429 mutex_lock(&trace_types_lock
);
4431 if (cpu
== RING_BUFFER_ALL_CPUS
) {
4432 int cpu
, buf_size_same
;
4437 /* check if all cpu sizes are same */
4438 for_each_tracing_cpu(cpu
) {
4439 /* fill in the size from first enabled cpu */
4441 size
= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
;
4442 if (size
!= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
) {
4448 if (buf_size_same
) {
4449 if (!ring_buffer_expanded
)
4450 r
= sprintf(buf
, "%lu (expanded: %lu)\n",
4452 trace_buf_size
>> 10);
4454 r
= sprintf(buf
, "%lu\n", size
>> 10);
4456 r
= sprintf(buf
, "X\n");
4458 r
= sprintf(buf
, "%lu\n", per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
>> 10);
4460 mutex_unlock(&trace_types_lock
);
4462 ret
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
4467 tracing_entries_write(struct file
*filp
, const char __user
*ubuf
,
4468 size_t cnt
, loff_t
*ppos
)
4470 struct inode
*inode
= file_inode(filp
);
4471 struct trace_array
*tr
= inode
->i_private
;
4475 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
4479 /* must have at least 1 entry */
4483 /* value is in KB */
4485 ret
= tracing_resize_ring_buffer(tr
, val
, tracing_get_cpu(inode
));
4495 tracing_total_entries_read(struct file
*filp
, char __user
*ubuf
,
4496 size_t cnt
, loff_t
*ppos
)
4498 struct trace_array
*tr
= filp
->private_data
;
4501 unsigned long size
= 0, expanded_size
= 0;
4503 mutex_lock(&trace_types_lock
);
4504 for_each_tracing_cpu(cpu
) {
4505 size
+= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
>> 10;
4506 if (!ring_buffer_expanded
)
4507 expanded_size
+= trace_buf_size
>> 10;
4509 if (ring_buffer_expanded
)
4510 r
= sprintf(buf
, "%lu\n", size
);
4512 r
= sprintf(buf
, "%lu (expanded: %lu)\n", size
, expanded_size
);
4513 mutex_unlock(&trace_types_lock
);
4515 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
4519 tracing_free_buffer_write(struct file
*filp
, const char __user
*ubuf
,
4520 size_t cnt
, loff_t
*ppos
)
4523 * There is no need to read what the user has written, this function
4524 * is just to make sure that there is no error when "echo" is used
4533 tracing_free_buffer_release(struct inode
*inode
, struct file
*filp
)
4535 struct trace_array
*tr
= inode
->i_private
;
4537 /* disable tracing ? */
4538 if (trace_flags
& TRACE_ITER_STOP_ON_FREE
)
4539 tracer_tracing_off(tr
);
4540 /* resize the ring buffer to 0 */
4541 tracing_resize_ring_buffer(tr
, 0, RING_BUFFER_ALL_CPUS
);
4543 trace_array_put(tr
);
4549 tracing_mark_write(struct file
*filp
, const char __user
*ubuf
,
4550 size_t cnt
, loff_t
*fpos
)
4552 unsigned long addr
= (unsigned long)ubuf
;
4553 struct trace_array
*tr
= filp
->private_data
;
4554 struct ring_buffer_event
*event
;
4555 struct ring_buffer
*buffer
;
4556 struct print_entry
*entry
;
4557 unsigned long irq_flags
;
4558 struct page
*pages
[2];
4568 if (tracing_disabled
)
4571 if (!(trace_flags
& TRACE_ITER_MARKERS
))
4574 if (cnt
> TRACE_BUF_SIZE
)
4575 cnt
= TRACE_BUF_SIZE
;
4578 * Userspace is injecting traces into the kernel trace buffer.
4579 * We want to be as non intrusive as possible.
4580 * To do so, we do not want to allocate any special buffers
4581 * or take any locks, but instead write the userspace data
4582 * straight into the ring buffer.
4584 * First we need to pin the userspace buffer into memory,
4585 * which, most likely it is, because it just referenced it.
4586 * But there's no guarantee that it is. By using get_user_pages_fast()
4587 * and kmap_atomic/kunmap_atomic() we can get access to the
4588 * pages directly. We then write the data directly into the
4591 BUILD_BUG_ON(TRACE_BUF_SIZE
>= PAGE_SIZE
);
4593 /* check if we cross pages */
4594 if ((addr
& PAGE_MASK
) != ((addr
+ cnt
) & PAGE_MASK
))
4597 offset
= addr
& (PAGE_SIZE
- 1);
4600 ret
= get_user_pages_fast(addr
, nr_pages
, 0, pages
);
4601 if (ret
< nr_pages
) {
4603 put_page(pages
[ret
]);
4608 for (i
= 0; i
< nr_pages
; i
++)
4609 map_page
[i
] = kmap_atomic(pages
[i
]);
4611 local_save_flags(irq_flags
);
4612 size
= sizeof(*entry
) + cnt
+ 2; /* possible \n added */
4613 buffer
= tr
->trace_buffer
.buffer
;
4614 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, size
,
4615 irq_flags
, preempt_count());
4617 /* Ring buffer disabled, return as if not open for write */
4622 entry
= ring_buffer_event_data(event
);
4623 entry
->ip
= _THIS_IP_
;
4625 if (nr_pages
== 2) {
4626 len
= PAGE_SIZE
- offset
;
4627 memcpy(&entry
->buf
, map_page
[0] + offset
, len
);
4628 memcpy(&entry
->buf
[len
], map_page
[1], cnt
- len
);
4630 memcpy(&entry
->buf
, map_page
[0] + offset
, cnt
);
4632 if (entry
->buf
[cnt
- 1] != '\n') {
4633 entry
->buf
[cnt
] = '\n';
4634 entry
->buf
[cnt
+ 1] = '\0';
4636 entry
->buf
[cnt
] = '\0';
4638 __buffer_unlock_commit(buffer
, event
);
4645 for (i
= 0; i
< nr_pages
; i
++){
4646 kunmap_atomic(map_page
[i
]);
4653 static int tracing_clock_show(struct seq_file
*m
, void *v
)
4655 struct trace_array
*tr
= m
->private;
4658 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++)
4660 "%s%s%s%s", i
? " " : "",
4661 i
== tr
->clock_id
? "[" : "", trace_clocks
[i
].name
,
4662 i
== tr
->clock_id
? "]" : "");
4668 static ssize_t
tracing_clock_write(struct file
*filp
, const char __user
*ubuf
,
4669 size_t cnt
, loff_t
*fpos
)
4671 struct seq_file
*m
= filp
->private_data
;
4672 struct trace_array
*tr
= m
->private;
4674 const char *clockstr
;
4677 if (cnt
>= sizeof(buf
))
4680 if (copy_from_user(&buf
, ubuf
, cnt
))
4685 clockstr
= strstrip(buf
);
4687 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++) {
4688 if (strcmp(trace_clocks
[i
].name
, clockstr
) == 0)
4691 if (i
== ARRAY_SIZE(trace_clocks
))
4694 mutex_lock(&trace_types_lock
);
4698 ring_buffer_set_clock(tr
->trace_buffer
.buffer
, trace_clocks
[i
].func
);
4701 * New clock may not be consistent with the previous clock.
4702 * Reset the buffer so that it doesn't have incomparable timestamps.
4704 tracing_reset_online_cpus(&tr
->trace_buffer
);
4706 #ifdef CONFIG_TRACER_MAX_TRACE
4707 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
&& tr
->max_buffer
.buffer
)
4708 ring_buffer_set_clock(tr
->max_buffer
.buffer
, trace_clocks
[i
].func
);
4709 tracing_reset_online_cpus(&tr
->max_buffer
);
4712 mutex_unlock(&trace_types_lock
);
4719 static int tracing_clock_open(struct inode
*inode
, struct file
*file
)
4721 struct trace_array
*tr
= inode
->i_private
;
4724 if (tracing_disabled
)
4727 if (trace_array_get(tr
))
4730 ret
= single_open(file
, tracing_clock_show
, inode
->i_private
);
4732 trace_array_put(tr
);
4737 struct ftrace_buffer_info
{
4738 struct trace_iterator iter
;
4743 #ifdef CONFIG_TRACER_SNAPSHOT
4744 static int tracing_snapshot_open(struct inode
*inode
, struct file
*file
)
4746 struct trace_array
*tr
= inode
->i_private
;
4747 struct trace_iterator
*iter
;
4751 if (trace_array_get(tr
) < 0)
4754 if (file
->f_mode
& FMODE_READ
) {
4755 iter
= __tracing_open(inode
, file
, true);
4757 ret
= PTR_ERR(iter
);
4759 /* Writes still need the seq_file to hold the private data */
4761 m
= kzalloc(sizeof(*m
), GFP_KERNEL
);
4764 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
4772 iter
->trace_buffer
= &tr
->max_buffer
;
4773 iter
->cpu_file
= tracing_get_cpu(inode
);
4775 file
->private_data
= m
;
4779 trace_array_put(tr
);
4785 tracing_snapshot_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
4788 struct seq_file
*m
= filp
->private_data
;
4789 struct trace_iterator
*iter
= m
->private;
4790 struct trace_array
*tr
= iter
->tr
;
4794 ret
= tracing_update_buffers();
4798 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
4802 mutex_lock(&trace_types_lock
);
4804 if (tr
->current_trace
->use_max_tr
) {
4811 if (iter
->cpu_file
!= RING_BUFFER_ALL_CPUS
) {
4815 if (tr
->allocated_snapshot
)
4819 /* Only allow per-cpu swap if the ring buffer supports it */
4820 #ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
4821 if (iter
->cpu_file
!= RING_BUFFER_ALL_CPUS
) {
4826 if (!tr
->allocated_snapshot
) {
4827 ret
= alloc_snapshot(tr
);
4831 local_irq_disable();
4832 /* Now, we're going to swap */
4833 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
)
4834 update_max_tr(tr
, current
, smp_processor_id());
4836 update_max_tr_single(tr
, current
, iter
->cpu_file
);
4840 if (tr
->allocated_snapshot
) {
4841 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
)
4842 tracing_reset_online_cpus(&tr
->max_buffer
);
4844 tracing_reset(&tr
->max_buffer
, iter
->cpu_file
);
4854 mutex_unlock(&trace_types_lock
);
4858 static int tracing_snapshot_release(struct inode
*inode
, struct file
*file
)
4860 struct seq_file
*m
= file
->private_data
;
4863 ret
= tracing_release(inode
, file
);
4865 if (file
->f_mode
& FMODE_READ
)
4868 /* If write only, the seq_file is just a stub */
4876 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
);
4877 static ssize_t
tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
4878 size_t count
, loff_t
*ppos
);
4879 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
);
4880 static ssize_t
tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
4881 struct pipe_inode_info
*pipe
, size_t len
, unsigned int flags
);
4883 static int snapshot_raw_open(struct inode
*inode
, struct file
*filp
)
4885 struct ftrace_buffer_info
*info
;
4888 ret
= tracing_buffers_open(inode
, filp
);
4892 info
= filp
->private_data
;
4894 if (info
->iter
.trace
->use_max_tr
) {
4895 tracing_buffers_release(inode
, filp
);
4899 info
->iter
.snapshot
= true;
4900 info
->iter
.trace_buffer
= &info
->iter
.tr
->max_buffer
;
4905 #endif /* CONFIG_TRACER_SNAPSHOT */
4908 static const struct file_operations tracing_max_lat_fops
= {
4909 .open
= tracing_open_generic
,
4910 .read
= tracing_max_lat_read
,
4911 .write
= tracing_max_lat_write
,
4912 .llseek
= generic_file_llseek
,
4915 static const struct file_operations set_tracer_fops
= {
4916 .open
= tracing_open_generic
,
4917 .read
= tracing_set_trace_read
,
4918 .write
= tracing_set_trace_write
,
4919 .llseek
= generic_file_llseek
,
4922 static const struct file_operations tracing_pipe_fops
= {
4923 .open
= tracing_open_pipe
,
4924 .poll
= tracing_poll_pipe
,
4925 .read
= tracing_read_pipe
,
4926 .splice_read
= tracing_splice_read_pipe
,
4927 .release
= tracing_release_pipe
,
4928 .llseek
= no_llseek
,
4931 static const struct file_operations tracing_entries_fops
= {
4932 .open
= tracing_open_generic_tr
,
4933 .read
= tracing_entries_read
,
4934 .write
= tracing_entries_write
,
4935 .llseek
= generic_file_llseek
,
4936 .release
= tracing_release_generic_tr
,
4939 static const struct file_operations tracing_total_entries_fops
= {
4940 .open
= tracing_open_generic_tr
,
4941 .read
= tracing_total_entries_read
,
4942 .llseek
= generic_file_llseek
,
4943 .release
= tracing_release_generic_tr
,
4946 static const struct file_operations tracing_free_buffer_fops
= {
4947 .open
= tracing_open_generic_tr
,
4948 .write
= tracing_free_buffer_write
,
4949 .release
= tracing_free_buffer_release
,
4952 static const struct file_operations tracing_mark_fops
= {
4953 .open
= tracing_open_generic_tr
,
4954 .write
= tracing_mark_write
,
4955 .llseek
= generic_file_llseek
,
4956 .release
= tracing_release_generic_tr
,
4959 static const struct file_operations trace_clock_fops
= {
4960 .open
= tracing_clock_open
,
4962 .llseek
= seq_lseek
,
4963 .release
= tracing_single_release_tr
,
4964 .write
= tracing_clock_write
,
4967 #ifdef CONFIG_TRACER_SNAPSHOT
4968 static const struct file_operations snapshot_fops
= {
4969 .open
= tracing_snapshot_open
,
4971 .write
= tracing_snapshot_write
,
4972 .llseek
= tracing_lseek
,
4973 .release
= tracing_snapshot_release
,
4976 static const struct file_operations snapshot_raw_fops
= {
4977 .open
= snapshot_raw_open
,
4978 .read
= tracing_buffers_read
,
4979 .release
= tracing_buffers_release
,
4980 .splice_read
= tracing_buffers_splice_read
,
4981 .llseek
= no_llseek
,
4984 #endif /* CONFIG_TRACER_SNAPSHOT */
4986 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
)
4988 struct trace_array
*tr
= inode
->i_private
;
4989 struct ftrace_buffer_info
*info
;
4992 if (tracing_disabled
)
4995 if (trace_array_get(tr
) < 0)
4998 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
5000 trace_array_put(tr
);
5004 mutex_lock(&trace_types_lock
);
5007 info
->iter
.cpu_file
= tracing_get_cpu(inode
);
5008 info
->iter
.trace
= tr
->current_trace
;
5009 info
->iter
.trace_buffer
= &tr
->trace_buffer
;
5011 /* Force reading ring buffer for first read */
5012 info
->read
= (unsigned int)-1;
5014 filp
->private_data
= info
;
5016 mutex_unlock(&trace_types_lock
);
5018 ret
= nonseekable_open(inode
, filp
);
5020 trace_array_put(tr
);
5026 tracing_buffers_poll(struct file
*filp
, poll_table
*poll_table
)
5028 struct ftrace_buffer_info
*info
= filp
->private_data
;
5029 struct trace_iterator
*iter
= &info
->iter
;
5031 return trace_poll(iter
, filp
, poll_table
);
5035 tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
5036 size_t count
, loff_t
*ppos
)
5038 struct ftrace_buffer_info
*info
= filp
->private_data
;
5039 struct trace_iterator
*iter
= &info
->iter
;
5046 mutex_lock(&trace_types_lock
);
5048 #ifdef CONFIG_TRACER_MAX_TRACE
5049 if (iter
->snapshot
&& iter
->tr
->current_trace
->use_max_tr
) {
5056 info
->spare
= ring_buffer_alloc_read_page(iter
->trace_buffer
->buffer
,
5062 /* Do we have previous read data to read? */
5063 if (info
->read
< PAGE_SIZE
)
5067 trace_access_lock(iter
->cpu_file
);
5068 ret
= ring_buffer_read_page(iter
->trace_buffer
->buffer
,
5072 trace_access_unlock(iter
->cpu_file
);
5075 if (trace_empty(iter
)) {
5076 if ((filp
->f_flags
& O_NONBLOCK
)) {
5080 mutex_unlock(&trace_types_lock
);
5081 iter
->trace
->wait_pipe(iter
);
5082 mutex_lock(&trace_types_lock
);
5083 if (signal_pending(current
)) {
5095 size
= PAGE_SIZE
- info
->read
;
5099 ret
= copy_to_user(ubuf
, info
->spare
+ info
->read
, size
);
5110 mutex_unlock(&trace_types_lock
);
5115 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
)
5117 struct ftrace_buffer_info
*info
= file
->private_data
;
5118 struct trace_iterator
*iter
= &info
->iter
;
5120 mutex_lock(&trace_types_lock
);
5122 __trace_array_put(iter
->tr
);
5125 ring_buffer_free_read_page(iter
->trace_buffer
->buffer
, info
->spare
);
5128 mutex_unlock(&trace_types_lock
);
5134 struct ring_buffer
*buffer
;
5139 static void buffer_pipe_buf_release(struct pipe_inode_info
*pipe
,
5140 struct pipe_buffer
*buf
)
5142 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
5147 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
5152 static void buffer_pipe_buf_get(struct pipe_inode_info
*pipe
,
5153 struct pipe_buffer
*buf
)
5155 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
5160 /* Pipe buffer operations for a buffer. */
5161 static const struct pipe_buf_operations buffer_pipe_buf_ops
= {
5163 .map
= generic_pipe_buf_map
,
5164 .unmap
= generic_pipe_buf_unmap
,
5165 .confirm
= generic_pipe_buf_confirm
,
5166 .release
= buffer_pipe_buf_release
,
5167 .steal
= generic_pipe_buf_steal
,
5168 .get
= buffer_pipe_buf_get
,
5172 * Callback from splice_to_pipe(), if we need to release some pages
5173 * at the end of the spd in case we error'ed out in filling the pipe.
5175 static void buffer_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
5177 struct buffer_ref
*ref
=
5178 (struct buffer_ref
*)spd
->partial
[i
].private;
5183 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
5185 spd
->partial
[i
].private = 0;
5189 tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
5190 struct pipe_inode_info
*pipe
, size_t len
,
5193 struct ftrace_buffer_info
*info
= file
->private_data
;
5194 struct trace_iterator
*iter
= &info
->iter
;
5195 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
5196 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
5197 struct splice_pipe_desc spd
= {
5199 .partial
= partial_def
,
5200 .nr_pages_max
= PIPE_DEF_BUFFERS
,
5202 .ops
= &buffer_pipe_buf_ops
,
5203 .spd_release
= buffer_spd_release
,
5205 struct buffer_ref
*ref
;
5206 int entries
, size
, i
;
5209 mutex_lock(&trace_types_lock
);
5211 #ifdef CONFIG_TRACER_MAX_TRACE
5212 if (iter
->snapshot
&& iter
->tr
->current_trace
->use_max_tr
) {
5218 if (splice_grow_spd(pipe
, &spd
)) {
5223 if (*ppos
& (PAGE_SIZE
- 1)) {
5228 if (len
& (PAGE_SIZE
- 1)) {
5229 if (len
< PAGE_SIZE
) {
5237 trace_access_lock(iter
->cpu_file
);
5238 entries
= ring_buffer_entries_cpu(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
5240 for (i
= 0; i
< pipe
->buffers
&& len
&& entries
; i
++, len
-= PAGE_SIZE
) {
5244 ref
= kzalloc(sizeof(*ref
), GFP_KERNEL
);
5249 ref
->buffer
= iter
->trace_buffer
->buffer
;
5250 ref
->page
= ring_buffer_alloc_read_page(ref
->buffer
, iter
->cpu_file
);
5256 r
= ring_buffer_read_page(ref
->buffer
, &ref
->page
,
5257 len
, iter
->cpu_file
, 1);
5259 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
5265 * zero out any left over data, this is going to
5268 size
= ring_buffer_page_len(ref
->page
);
5269 if (size
< PAGE_SIZE
)
5270 memset(ref
->page
+ size
, 0, PAGE_SIZE
- size
);
5272 page
= virt_to_page(ref
->page
);
5274 spd
.pages
[i
] = page
;
5275 spd
.partial
[i
].len
= PAGE_SIZE
;
5276 spd
.partial
[i
].offset
= 0;
5277 spd
.partial
[i
].private = (unsigned long)ref
;
5281 entries
= ring_buffer_entries_cpu(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
5284 trace_access_unlock(iter
->cpu_file
);
5287 /* did we read anything? */
5288 if (!spd
.nr_pages
) {
5289 if ((file
->f_flags
& O_NONBLOCK
) || (flags
& SPLICE_F_NONBLOCK
)) {
5293 mutex_unlock(&trace_types_lock
);
5294 iter
->trace
->wait_pipe(iter
);
5295 mutex_lock(&trace_types_lock
);
5296 if (signal_pending(current
)) {
5303 ret
= splice_to_pipe(pipe
, &spd
);
5304 splice_shrink_spd(&spd
);
5306 mutex_unlock(&trace_types_lock
);
5311 static const struct file_operations tracing_buffers_fops
= {
5312 .open
= tracing_buffers_open
,
5313 .read
= tracing_buffers_read
,
5314 .poll
= tracing_buffers_poll
,
5315 .release
= tracing_buffers_release
,
5316 .splice_read
= tracing_buffers_splice_read
,
5317 .llseek
= no_llseek
,
5321 tracing_stats_read(struct file
*filp
, char __user
*ubuf
,
5322 size_t count
, loff_t
*ppos
)
5324 struct inode
*inode
= file_inode(filp
);
5325 struct trace_array
*tr
= inode
->i_private
;
5326 struct trace_buffer
*trace_buf
= &tr
->trace_buffer
;
5327 int cpu
= tracing_get_cpu(inode
);
5328 struct trace_seq
*s
;
5330 unsigned long long t
;
5331 unsigned long usec_rem
;
5333 s
= kmalloc(sizeof(*s
), GFP_KERNEL
);
5339 cnt
= ring_buffer_entries_cpu(trace_buf
->buffer
, cpu
);
5340 trace_seq_printf(s
, "entries: %ld\n", cnt
);
5342 cnt
= ring_buffer_overrun_cpu(trace_buf
->buffer
, cpu
);
5343 trace_seq_printf(s
, "overrun: %ld\n", cnt
);
5345 cnt
= ring_buffer_commit_overrun_cpu(trace_buf
->buffer
, cpu
);
5346 trace_seq_printf(s
, "commit overrun: %ld\n", cnt
);
5348 cnt
= ring_buffer_bytes_cpu(trace_buf
->buffer
, cpu
);
5349 trace_seq_printf(s
, "bytes: %ld\n", cnt
);
5351 if (trace_clocks
[tr
->clock_id
].in_ns
) {
5352 /* local or global for trace_clock */
5353 t
= ns2usecs(ring_buffer_oldest_event_ts(trace_buf
->buffer
, cpu
));
5354 usec_rem
= do_div(t
, USEC_PER_SEC
);
5355 trace_seq_printf(s
, "oldest event ts: %5llu.%06lu\n",
5358 t
= ns2usecs(ring_buffer_time_stamp(trace_buf
->buffer
, cpu
));
5359 usec_rem
= do_div(t
, USEC_PER_SEC
);
5360 trace_seq_printf(s
, "now ts: %5llu.%06lu\n", t
, usec_rem
);
5362 /* counter or tsc mode for trace_clock */
5363 trace_seq_printf(s
, "oldest event ts: %llu\n",
5364 ring_buffer_oldest_event_ts(trace_buf
->buffer
, cpu
));
5366 trace_seq_printf(s
, "now ts: %llu\n",
5367 ring_buffer_time_stamp(trace_buf
->buffer
, cpu
));
5370 cnt
= ring_buffer_dropped_events_cpu(trace_buf
->buffer
, cpu
);
5371 trace_seq_printf(s
, "dropped events: %ld\n", cnt
);
5373 cnt
= ring_buffer_read_events_cpu(trace_buf
->buffer
, cpu
);
5374 trace_seq_printf(s
, "read events: %ld\n", cnt
);
5376 count
= simple_read_from_buffer(ubuf
, count
, ppos
, s
->buffer
, s
->len
);
5383 static const struct file_operations tracing_stats_fops
= {
5384 .open
= tracing_open_generic_tr
,
5385 .read
= tracing_stats_read
,
5386 .llseek
= generic_file_llseek
,
5387 .release
= tracing_release_generic_tr
,
5390 #ifdef CONFIG_DYNAMIC_FTRACE
5392 int __weak
ftrace_arch_read_dyn_info(char *buf
, int size
)
5398 tracing_read_dyn_info(struct file
*filp
, char __user
*ubuf
,
5399 size_t cnt
, loff_t
*ppos
)
5401 static char ftrace_dyn_info_buffer
[1024];
5402 static DEFINE_MUTEX(dyn_info_mutex
);
5403 unsigned long *p
= filp
->private_data
;
5404 char *buf
= ftrace_dyn_info_buffer
;
5405 int size
= ARRAY_SIZE(ftrace_dyn_info_buffer
);
5408 mutex_lock(&dyn_info_mutex
);
5409 r
= sprintf(buf
, "%ld ", *p
);
5411 r
+= ftrace_arch_read_dyn_info(buf
+r
, (size
-1)-r
);
5414 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
5416 mutex_unlock(&dyn_info_mutex
);
5421 static const struct file_operations tracing_dyn_info_fops
= {
5422 .open
= tracing_open_generic
,
5423 .read
= tracing_read_dyn_info
,
5424 .llseek
= generic_file_llseek
,
5426 #endif /* CONFIG_DYNAMIC_FTRACE */
5428 #if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
5430 ftrace_snapshot(unsigned long ip
, unsigned long parent_ip
, void **data
)
5436 ftrace_count_snapshot(unsigned long ip
, unsigned long parent_ip
, void **data
)
5438 unsigned long *count
= (long *)data
;
5450 ftrace_snapshot_print(struct seq_file
*m
, unsigned long ip
,
5451 struct ftrace_probe_ops
*ops
, void *data
)
5453 long count
= (long)data
;
5455 seq_printf(m
, "%ps:", (void *)ip
);
5457 seq_printf(m
, "snapshot");
5460 seq_printf(m
, ":unlimited\n");
5462 seq_printf(m
, ":count=%ld\n", count
);
5467 static struct ftrace_probe_ops snapshot_probe_ops
= {
5468 .func
= ftrace_snapshot
,
5469 .print
= ftrace_snapshot_print
,
5472 static struct ftrace_probe_ops snapshot_count_probe_ops
= {
5473 .func
= ftrace_count_snapshot
,
5474 .print
= ftrace_snapshot_print
,
5478 ftrace_trace_snapshot_callback(struct ftrace_hash
*hash
,
5479 char *glob
, char *cmd
, char *param
, int enable
)
5481 struct ftrace_probe_ops
*ops
;
5482 void *count
= (void *)-1;
5486 /* hash funcs only work with set_ftrace_filter */
5490 ops
= param
? &snapshot_count_probe_ops
: &snapshot_probe_ops
;
5492 if (glob
[0] == '!') {
5493 unregister_ftrace_function_probe_func(glob
+1, ops
);
5500 number
= strsep(¶m
, ":");
5502 if (!strlen(number
))
5506 * We use the callback data field (which is a pointer)
5509 ret
= kstrtoul(number
, 0, (unsigned long *)&count
);
5514 ret
= register_ftrace_function_probe(glob
, ops
, count
);
5517 alloc_snapshot(&global_trace
);
5519 return ret
< 0 ? ret
: 0;
5522 static struct ftrace_func_command ftrace_snapshot_cmd
= {
5524 .func
= ftrace_trace_snapshot_callback
,
5527 static __init
int register_snapshot_cmd(void)
5529 return register_ftrace_command(&ftrace_snapshot_cmd
);
5532 static inline __init
int register_snapshot_cmd(void) { return 0; }
5533 #endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
5535 struct dentry
*tracing_init_dentry_tr(struct trace_array
*tr
)
5540 if (!debugfs_initialized())
5543 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
5544 tr
->dir
= debugfs_create_dir("tracing", NULL
);
5547 pr_warn_once("Could not create debugfs directory 'tracing'\n");
5552 struct dentry
*tracing_init_dentry(void)
5554 return tracing_init_dentry_tr(&global_trace
);
5557 static struct dentry
*tracing_dentry_percpu(struct trace_array
*tr
, int cpu
)
5559 struct dentry
*d_tracer
;
5562 return tr
->percpu_dir
;
5564 d_tracer
= tracing_init_dentry_tr(tr
);
5568 tr
->percpu_dir
= debugfs_create_dir("per_cpu", d_tracer
);
5570 WARN_ONCE(!tr
->percpu_dir
,
5571 "Could not create debugfs directory 'per_cpu/%d'\n", cpu
);
5573 return tr
->percpu_dir
;
5576 static struct dentry
*
5577 trace_create_cpu_file(const char *name
, umode_t mode
, struct dentry
*parent
,
5578 void *data
, long cpu
, const struct file_operations
*fops
)
5580 struct dentry
*ret
= trace_create_file(name
, mode
, parent
, data
, fops
);
5582 if (ret
) /* See tracing_get_cpu() */
5583 ret
->d_inode
->i_cdev
= (void *)(cpu
+ 1);
5588 tracing_init_debugfs_percpu(struct trace_array
*tr
, long cpu
)
5590 struct dentry
*d_percpu
= tracing_dentry_percpu(tr
, cpu
);
5591 struct dentry
*d_cpu
;
5592 char cpu_dir
[30]; /* 30 characters should be more than enough */
5597 snprintf(cpu_dir
, 30, "cpu%ld", cpu
);
5598 d_cpu
= debugfs_create_dir(cpu_dir
, d_percpu
);
5600 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir
);
5604 /* per cpu trace_pipe */
5605 trace_create_cpu_file("trace_pipe", 0444, d_cpu
,
5606 tr
, cpu
, &tracing_pipe_fops
);
5609 trace_create_cpu_file("trace", 0644, d_cpu
,
5610 tr
, cpu
, &tracing_fops
);
5612 trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu
,
5613 tr
, cpu
, &tracing_buffers_fops
);
5615 trace_create_cpu_file("stats", 0444, d_cpu
,
5616 tr
, cpu
, &tracing_stats_fops
);
5618 trace_create_cpu_file("buffer_size_kb", 0444, d_cpu
,
5619 tr
, cpu
, &tracing_entries_fops
);
5621 #ifdef CONFIG_TRACER_SNAPSHOT
5622 trace_create_cpu_file("snapshot", 0644, d_cpu
,
5623 tr
, cpu
, &snapshot_fops
);
5625 trace_create_cpu_file("snapshot_raw", 0444, d_cpu
,
5626 tr
, cpu
, &snapshot_raw_fops
);
5630 #ifdef CONFIG_FTRACE_SELFTEST
5631 /* Let selftest have access to static functions in this file */
5632 #include "trace_selftest.c"
5635 struct trace_option_dentry
{
5636 struct tracer_opt
*opt
;
5637 struct tracer_flags
*flags
;
5638 struct trace_array
*tr
;
5639 struct dentry
*entry
;
5643 trace_options_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
5646 struct trace_option_dentry
*topt
= filp
->private_data
;
5649 if (topt
->flags
->val
& topt
->opt
->bit
)
5654 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
5658 trace_options_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
5661 struct trace_option_dentry
*topt
= filp
->private_data
;
5665 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5669 if (val
!= 0 && val
!= 1)
5672 if (!!(topt
->flags
->val
& topt
->opt
->bit
) != val
) {
5673 mutex_lock(&trace_types_lock
);
5674 ret
= __set_tracer_option(topt
->tr
->current_trace
, topt
->flags
,
5676 mutex_unlock(&trace_types_lock
);
5687 static const struct file_operations trace_options_fops
= {
5688 .open
= tracing_open_generic
,
5689 .read
= trace_options_read
,
5690 .write
= trace_options_write
,
5691 .llseek
= generic_file_llseek
,
5695 trace_options_core_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
5698 long index
= (long)filp
->private_data
;
5701 if (trace_flags
& (1 << index
))
5706 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
5710 trace_options_core_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
5713 struct trace_array
*tr
= &global_trace
;
5714 long index
= (long)filp
->private_data
;
5718 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5722 if (val
!= 0 && val
!= 1)
5725 mutex_lock(&trace_types_lock
);
5726 ret
= set_tracer_flag(tr
, 1 << index
, val
);
5727 mutex_unlock(&trace_types_lock
);
5737 static const struct file_operations trace_options_core_fops
= {
5738 .open
= tracing_open_generic
,
5739 .read
= trace_options_core_read
,
5740 .write
= trace_options_core_write
,
5741 .llseek
= generic_file_llseek
,
5744 struct dentry
*trace_create_file(const char *name
,
5746 struct dentry
*parent
,
5748 const struct file_operations
*fops
)
5752 ret
= debugfs_create_file(name
, mode
, parent
, data
, fops
);
5754 pr_warning("Could not create debugfs '%s' entry\n", name
);
5760 static struct dentry
*trace_options_init_dentry(struct trace_array
*tr
)
5762 struct dentry
*d_tracer
;
5767 d_tracer
= tracing_init_dentry_tr(tr
);
5771 tr
->options
= debugfs_create_dir("options", d_tracer
);
5773 pr_warning("Could not create debugfs directory 'options'\n");
5781 create_trace_option_file(struct trace_array
*tr
,
5782 struct trace_option_dentry
*topt
,
5783 struct tracer_flags
*flags
,
5784 struct tracer_opt
*opt
)
5786 struct dentry
*t_options
;
5788 t_options
= trace_options_init_dentry(tr
);
5792 topt
->flags
= flags
;
5796 topt
->entry
= trace_create_file(opt
->name
, 0644, t_options
, topt
,
5797 &trace_options_fops
);
5801 static struct trace_option_dentry
*
5802 create_trace_option_files(struct trace_array
*tr
, struct tracer
*tracer
)
5804 struct trace_option_dentry
*topts
;
5805 struct tracer_flags
*flags
;
5806 struct tracer_opt
*opts
;
5812 flags
= tracer
->flags
;
5814 if (!flags
|| !flags
->opts
)
5819 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
5822 topts
= kcalloc(cnt
+ 1, sizeof(*topts
), GFP_KERNEL
);
5826 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
5827 create_trace_option_file(tr
, &topts
[cnt
], flags
,
5834 destroy_trace_option_files(struct trace_option_dentry
*topts
)
5841 for (cnt
= 0; topts
[cnt
].opt
; cnt
++) {
5842 if (topts
[cnt
].entry
)
5843 debugfs_remove(topts
[cnt
].entry
);
5849 static struct dentry
*
5850 create_trace_option_core_file(struct trace_array
*tr
,
5851 const char *option
, long index
)
5853 struct dentry
*t_options
;
5855 t_options
= trace_options_init_dentry(tr
);
5859 return trace_create_file(option
, 0644, t_options
, (void *)index
,
5860 &trace_options_core_fops
);
5863 static __init
void create_trace_options_dir(struct trace_array
*tr
)
5865 struct dentry
*t_options
;
5868 t_options
= trace_options_init_dentry(tr
);
5872 for (i
= 0; trace_options
[i
]; i
++)
5873 create_trace_option_core_file(tr
, trace_options
[i
], i
);
5877 rb_simple_read(struct file
*filp
, char __user
*ubuf
,
5878 size_t cnt
, loff_t
*ppos
)
5880 struct trace_array
*tr
= filp
->private_data
;
5884 r
= tracer_tracing_is_on(tr
);
5885 r
= sprintf(buf
, "%d\n", r
);
5887 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
5891 rb_simple_write(struct file
*filp
, const char __user
*ubuf
,
5892 size_t cnt
, loff_t
*ppos
)
5894 struct trace_array
*tr
= filp
->private_data
;
5895 struct ring_buffer
*buffer
= tr
->trace_buffer
.buffer
;
5899 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5904 mutex_lock(&trace_types_lock
);
5906 tracer_tracing_on(tr
);
5907 if (tr
->current_trace
->start
)
5908 tr
->current_trace
->start(tr
);
5910 tracer_tracing_off(tr
);
5911 if (tr
->current_trace
->stop
)
5912 tr
->current_trace
->stop(tr
);
5914 mutex_unlock(&trace_types_lock
);
5922 static const struct file_operations rb_simple_fops
= {
5923 .open
= tracing_open_generic_tr
,
5924 .read
= rb_simple_read
,
5925 .write
= rb_simple_write
,
5926 .release
= tracing_release_generic_tr
,
5927 .llseek
= default_llseek
,
5930 struct dentry
*trace_instance_dir
;
5933 init_tracer_debugfs(struct trace_array
*tr
, struct dentry
*d_tracer
);
5936 allocate_trace_buffer(struct trace_array
*tr
, struct trace_buffer
*buf
, int size
)
5938 enum ring_buffer_flags rb_flags
;
5940 rb_flags
= trace_flags
& TRACE_ITER_OVERWRITE
? RB_FL_OVERWRITE
: 0;
5944 buf
->buffer
= ring_buffer_alloc(size
, rb_flags
);
5948 buf
->data
= alloc_percpu(struct trace_array_cpu
);
5950 ring_buffer_free(buf
->buffer
);
5954 /* Allocate the first page for all buffers */
5955 set_buffer_entries(&tr
->trace_buffer
,
5956 ring_buffer_size(tr
->trace_buffer
.buffer
, 0));
5961 static int allocate_trace_buffers(struct trace_array
*tr
, int size
)
5965 ret
= allocate_trace_buffer(tr
, &tr
->trace_buffer
, size
);
5969 #ifdef CONFIG_TRACER_MAX_TRACE
5970 ret
= allocate_trace_buffer(tr
, &tr
->max_buffer
,
5971 allocate_snapshot
? size
: 1);
5973 ring_buffer_free(tr
->trace_buffer
.buffer
);
5974 free_percpu(tr
->trace_buffer
.data
);
5977 tr
->allocated_snapshot
= allocate_snapshot
;
5980 * Only the top level trace array gets its snapshot allocated
5981 * from the kernel command line.
5983 allocate_snapshot
= false;
5988 static int new_instance_create(const char *name
)
5990 struct trace_array
*tr
;
5993 mutex_lock(&trace_types_lock
);
5996 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
5997 if (tr
->name
&& strcmp(tr
->name
, name
) == 0)
6002 tr
= kzalloc(sizeof(*tr
), GFP_KERNEL
);
6006 tr
->name
= kstrdup(name
, GFP_KERNEL
);
6010 if (!alloc_cpumask_var(&tr
->tracing_cpumask
, GFP_KERNEL
))
6013 cpumask_copy(tr
->tracing_cpumask
, cpu_all_mask
);
6015 raw_spin_lock_init(&tr
->start_lock
);
6017 tr
->current_trace
= &nop_trace
;
6019 INIT_LIST_HEAD(&tr
->systems
);
6020 INIT_LIST_HEAD(&tr
->events
);
6022 if (allocate_trace_buffers(tr
, trace_buf_size
) < 0)
6025 tr
->dir
= debugfs_create_dir(name
, trace_instance_dir
);
6029 ret
= event_trace_add_tracer(tr
->dir
, tr
);
6031 debugfs_remove_recursive(tr
->dir
);
6035 init_tracer_debugfs(tr
, tr
->dir
);
6037 list_add(&tr
->list
, &ftrace_trace_arrays
);
6039 mutex_unlock(&trace_types_lock
);
6044 if (tr
->trace_buffer
.buffer
)
6045 ring_buffer_free(tr
->trace_buffer
.buffer
);
6046 free_cpumask_var(tr
->tracing_cpumask
);
6051 mutex_unlock(&trace_types_lock
);
6057 static int instance_delete(const char *name
)
6059 struct trace_array
*tr
;
6063 mutex_lock(&trace_types_lock
);
6066 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
6067 if (tr
->name
&& strcmp(tr
->name
, name
) == 0) {
6079 list_del(&tr
->list
);
6081 event_trace_del_tracer(tr
);
6082 debugfs_remove_recursive(tr
->dir
);
6083 free_percpu(tr
->trace_buffer
.data
);
6084 ring_buffer_free(tr
->trace_buffer
.buffer
);
6092 mutex_unlock(&trace_types_lock
);
6097 static int instance_mkdir (struct inode
*inode
, struct dentry
*dentry
, umode_t mode
)
6099 struct dentry
*parent
;
6102 /* Paranoid: Make sure the parent is the "instances" directory */
6103 parent
= hlist_entry(inode
->i_dentry
.first
, struct dentry
, d_alias
);
6104 if (WARN_ON_ONCE(parent
!= trace_instance_dir
))
6108 * The inode mutex is locked, but debugfs_create_dir() will also
6109 * take the mutex. As the instances directory can not be destroyed
6110 * or changed in any other way, it is safe to unlock it, and
6111 * let the dentry try. If two users try to make the same dir at
6112 * the same time, then the new_instance_create() will determine the
6115 mutex_unlock(&inode
->i_mutex
);
6117 ret
= new_instance_create(dentry
->d_iname
);
6119 mutex_lock(&inode
->i_mutex
);
6124 static int instance_rmdir(struct inode
*inode
, struct dentry
*dentry
)
6126 struct dentry
*parent
;
6129 /* Paranoid: Make sure the parent is the "instances" directory */
6130 parent
= hlist_entry(inode
->i_dentry
.first
, struct dentry
, d_alias
);
6131 if (WARN_ON_ONCE(parent
!= trace_instance_dir
))
6134 /* The caller did a dget() on dentry */
6135 mutex_unlock(&dentry
->d_inode
->i_mutex
);
6138 * The inode mutex is locked, but debugfs_create_dir() will also
6139 * take the mutex. As the instances directory can not be destroyed
6140 * or changed in any other way, it is safe to unlock it, and
6141 * let the dentry try. If two users try to make the same dir at
6142 * the same time, then the instance_delete() will determine the
6145 mutex_unlock(&inode
->i_mutex
);
6147 ret
= instance_delete(dentry
->d_iname
);
6149 mutex_lock_nested(&inode
->i_mutex
, I_MUTEX_PARENT
);
6150 mutex_lock(&dentry
->d_inode
->i_mutex
);
6155 static const struct inode_operations instance_dir_inode_operations
= {
6156 .lookup
= simple_lookup
,
6157 .mkdir
= instance_mkdir
,
6158 .rmdir
= instance_rmdir
,
6161 static __init
void create_trace_instances(struct dentry
*d_tracer
)
6163 trace_instance_dir
= debugfs_create_dir("instances", d_tracer
);
6164 if (WARN_ON(!trace_instance_dir
))
6167 /* Hijack the dir inode operations, to allow mkdir */
6168 trace_instance_dir
->d_inode
->i_op
= &instance_dir_inode_operations
;
6172 init_tracer_debugfs(struct trace_array
*tr
, struct dentry
*d_tracer
)
6176 trace_create_file("tracing_cpumask", 0644, d_tracer
,
6177 tr
, &tracing_cpumask_fops
);
6179 trace_create_file("trace_options", 0644, d_tracer
,
6180 tr
, &tracing_iter_fops
);
6182 trace_create_file("trace", 0644, d_tracer
,
6185 trace_create_file("trace_pipe", 0444, d_tracer
,
6186 tr
, &tracing_pipe_fops
);
6188 trace_create_file("buffer_size_kb", 0644, d_tracer
,
6189 tr
, &tracing_entries_fops
);
6191 trace_create_file("buffer_total_size_kb", 0444, d_tracer
,
6192 tr
, &tracing_total_entries_fops
);
6194 trace_create_file("free_buffer", 0200, d_tracer
,
6195 tr
, &tracing_free_buffer_fops
);
6197 trace_create_file("trace_marker", 0220, d_tracer
,
6198 tr
, &tracing_mark_fops
);
6200 trace_create_file("trace_clock", 0644, d_tracer
, tr
,
6203 trace_create_file("tracing_on", 0644, d_tracer
,
6204 tr
, &rb_simple_fops
);
6206 #ifdef CONFIG_TRACER_SNAPSHOT
6207 trace_create_file("snapshot", 0644, d_tracer
,
6208 tr
, &snapshot_fops
);
6211 for_each_tracing_cpu(cpu
)
6212 tracing_init_debugfs_percpu(tr
, cpu
);
6216 static __init
int tracer_init_debugfs(void)
6218 struct dentry
*d_tracer
;
6220 trace_access_lock_init();
6222 d_tracer
= tracing_init_dentry();
6226 init_tracer_debugfs(&global_trace
, d_tracer
);
6228 trace_create_file("available_tracers", 0444, d_tracer
,
6229 &global_trace
, &show_traces_fops
);
6231 trace_create_file("current_tracer", 0644, d_tracer
,
6232 &global_trace
, &set_tracer_fops
);
6234 #ifdef CONFIG_TRACER_MAX_TRACE
6235 trace_create_file("tracing_max_latency", 0644, d_tracer
,
6236 &tracing_max_latency
, &tracing_max_lat_fops
);
6239 trace_create_file("tracing_thresh", 0644, d_tracer
,
6240 &tracing_thresh
, &tracing_max_lat_fops
);
6242 trace_create_file("README", 0444, d_tracer
,
6243 NULL
, &tracing_readme_fops
);
6245 trace_create_file("saved_cmdlines", 0444, d_tracer
,
6246 NULL
, &tracing_saved_cmdlines_fops
);
6248 #ifdef CONFIG_DYNAMIC_FTRACE
6249 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
6250 &ftrace_update_tot_cnt
, &tracing_dyn_info_fops
);
6253 create_trace_instances(d_tracer
);
6255 create_trace_options_dir(&global_trace
);
6260 static int trace_panic_handler(struct notifier_block
*this,
6261 unsigned long event
, void *unused
)
6263 if (ftrace_dump_on_oops
)
6264 ftrace_dump(ftrace_dump_on_oops
);
6268 static struct notifier_block trace_panic_notifier
= {
6269 .notifier_call
= trace_panic_handler
,
6271 .priority
= 150 /* priority: INT_MAX >= x >= 0 */
6274 static int trace_die_handler(struct notifier_block
*self
,
6280 if (ftrace_dump_on_oops
)
6281 ftrace_dump(ftrace_dump_on_oops
);
6289 static struct notifier_block trace_die_notifier
= {
6290 .notifier_call
= trace_die_handler
,
6295 * printk is set to max of 1024, we really don't need it that big.
6296 * Nothing should be printing 1000 characters anyway.
6298 #define TRACE_MAX_PRINT 1000
6301 * Define here KERN_TRACE so that we have one place to modify
6302 * it if we decide to change what log level the ftrace dump
6305 #define KERN_TRACE KERN_EMERG
6308 trace_printk_seq(struct trace_seq
*s
)
6310 /* Probably should print a warning here. */
6311 if (s
->len
>= TRACE_MAX_PRINT
)
6312 s
->len
= TRACE_MAX_PRINT
;
6314 /* should be zero ended, but we are paranoid. */
6315 s
->buffer
[s
->len
] = 0;
6317 printk(KERN_TRACE
"%s", s
->buffer
);
6322 void trace_init_global_iter(struct trace_iterator
*iter
)
6324 iter
->tr
= &global_trace
;
6325 iter
->trace
= iter
->tr
->current_trace
;
6326 iter
->cpu_file
= RING_BUFFER_ALL_CPUS
;
6327 iter
->trace_buffer
= &global_trace
.trace_buffer
;
6329 if (iter
->trace
&& iter
->trace
->open
)
6330 iter
->trace
->open(iter
);
6332 /* Annotate start of buffers if we had overruns */
6333 if (ring_buffer_overruns(iter
->trace_buffer
->buffer
))
6334 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
6336 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
6337 if (trace_clocks
[iter
->tr
->clock_id
].in_ns
)
6338 iter
->iter_flags
|= TRACE_FILE_TIME_IN_NS
;
6341 void ftrace_dump(enum ftrace_dump_mode oops_dump_mode
)
6343 /* use static because iter can be a bit big for the stack */
6344 static struct trace_iterator iter
;
6345 static atomic_t dump_running
;
6346 unsigned int old_userobj
;
6347 unsigned long flags
;
6350 /* Only allow one dump user at a time. */
6351 if (atomic_inc_return(&dump_running
) != 1) {
6352 atomic_dec(&dump_running
);
6357 * Always turn off tracing when we dump.
6358 * We don't need to show trace output of what happens
6359 * between multiple crashes.
6361 * If the user does a sysrq-z, then they can re-enable
6362 * tracing with echo 1 > tracing_on.
6366 local_irq_save(flags
);
6368 /* Simulate the iterator */
6369 trace_init_global_iter(&iter
);
6371 for_each_tracing_cpu(cpu
) {
6372 atomic_inc(&per_cpu_ptr(iter
.tr
->trace_buffer
.data
, cpu
)->disabled
);
6375 old_userobj
= trace_flags
& TRACE_ITER_SYM_USEROBJ
;
6377 /* don't look at user memory in panic mode */
6378 trace_flags
&= ~TRACE_ITER_SYM_USEROBJ
;
6380 switch (oops_dump_mode
) {
6382 iter
.cpu_file
= RING_BUFFER_ALL_CPUS
;
6385 iter
.cpu_file
= raw_smp_processor_id();
6390 printk(KERN_TRACE
"Bad dumping mode, switching to all CPUs dump\n");
6391 iter
.cpu_file
= RING_BUFFER_ALL_CPUS
;
6394 printk(KERN_TRACE
"Dumping ftrace buffer:\n");
6396 /* Did function tracer already get disabled? */
6397 if (ftrace_is_dead()) {
6398 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
6399 printk("# MAY BE MISSING FUNCTION EVENTS\n");
6403 * We need to stop all tracing on all CPUS to read the
6404 * the next buffer. This is a bit expensive, but is
6405 * not done often. We fill all what we can read,
6406 * and then release the locks again.
6409 while (!trace_empty(&iter
)) {
6412 printk(KERN_TRACE
"---------------------------------\n");
6416 /* reset all but tr, trace, and overruns */
6417 memset(&iter
.seq
, 0,
6418 sizeof(struct trace_iterator
) -
6419 offsetof(struct trace_iterator
, seq
));
6420 iter
.iter_flags
|= TRACE_FILE_LAT_FMT
;
6423 if (trace_find_next_entry_inc(&iter
) != NULL
) {
6426 ret
= print_trace_line(&iter
);
6427 if (ret
!= TRACE_TYPE_NO_CONSUME
)
6428 trace_consume(&iter
);
6430 touch_nmi_watchdog();
6432 trace_printk_seq(&iter
.seq
);
6436 printk(KERN_TRACE
" (ftrace buffer empty)\n");
6438 printk(KERN_TRACE
"---------------------------------\n");
6441 trace_flags
|= old_userobj
;
6443 for_each_tracing_cpu(cpu
) {
6444 atomic_dec(&per_cpu_ptr(iter
.trace_buffer
->data
, cpu
)->disabled
);
6446 atomic_dec(&dump_running
);
6447 local_irq_restore(flags
);
6449 EXPORT_SYMBOL_GPL(ftrace_dump
);
6451 __init
static int tracer_alloc_buffers(void)
6457 if (!alloc_cpumask_var(&tracing_buffer_mask
, GFP_KERNEL
))
6460 if (!alloc_cpumask_var(&global_trace
.tracing_cpumask
, GFP_KERNEL
))
6461 goto out_free_buffer_mask
;
6463 /* Only allocate trace_printk buffers if a trace_printk exists */
6464 if (__stop___trace_bprintk_fmt
!= __start___trace_bprintk_fmt
)
6465 /* Must be called before global_trace.buffer is allocated */
6466 trace_printk_init_buffers();
6468 /* To save memory, keep the ring buffer size to its minimum */
6469 if (ring_buffer_expanded
)
6470 ring_buf_size
= trace_buf_size
;
6474 cpumask_copy(tracing_buffer_mask
, cpu_possible_mask
);
6475 cpumask_copy(global_trace
.tracing_cpumask
, cpu_all_mask
);
6477 raw_spin_lock_init(&global_trace
.start_lock
);
6479 /* TODO: make the number of buffers hot pluggable with CPUS */
6480 if (allocate_trace_buffers(&global_trace
, ring_buf_size
) < 0) {
6481 printk(KERN_ERR
"tracer: failed to allocate ring buffer!\n");
6483 goto out_free_cpumask
;
6486 if (global_trace
.buffer_disabled
)
6489 trace_init_cmdlines();
6492 * register_tracer() might reference current_trace, so it
6493 * needs to be set before we register anything. This is
6494 * just a bootstrap of current_trace anyway.
6496 global_trace
.current_trace
= &nop_trace
;
6498 register_tracer(&nop_trace
);
6500 /* All seems OK, enable tracing */
6501 tracing_disabled
= 0;
6503 atomic_notifier_chain_register(&panic_notifier_list
,
6504 &trace_panic_notifier
);
6506 register_die_notifier(&trace_die_notifier
);
6508 global_trace
.flags
= TRACE_ARRAY_FL_GLOBAL
;
6510 INIT_LIST_HEAD(&global_trace
.systems
);
6511 INIT_LIST_HEAD(&global_trace
.events
);
6512 list_add(&global_trace
.list
, &ftrace_trace_arrays
);
6514 while (trace_boot_options
) {
6517 option
= strsep(&trace_boot_options
, ",");
6518 trace_set_options(&global_trace
, option
);
6521 register_snapshot_cmd();
6526 free_percpu(global_trace
.trace_buffer
.data
);
6527 #ifdef CONFIG_TRACER_MAX_TRACE
6528 free_percpu(global_trace
.max_buffer
.data
);
6530 free_cpumask_var(global_trace
.tracing_cpumask
);
6531 out_free_buffer_mask
:
6532 free_cpumask_var(tracing_buffer_mask
);
6537 __init
static int clear_boot_tracer(void)
6540 * The default tracer at boot buffer is an init section.
6541 * This function is called in lateinit. If we did not
6542 * find the boot tracer, then clear it out, to prevent
6543 * later registration from accessing the buffer that is
6544 * about to be freed.
6546 if (!default_bootup_tracer
)
6549 printk(KERN_INFO
"ftrace bootup tracer '%s' not registered.\n",
6550 default_bootup_tracer
);
6551 default_bootup_tracer
= NULL
;
6556 early_initcall(tracer_alloc_buffers
);
6557 fs_initcall(tracer_init_debugfs
);
6558 late_initcall(clear_boot_tracer
);