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 filter_current_check_discard(struct ring_buffer
*buffer
,
208 struct ftrace_event_call
*call
, void *rec
,
209 struct ring_buffer_event
*event
)
211 return filter_check_discard(call
, rec
, buffer
, event
);
213 EXPORT_SYMBOL_GPL(filter_current_check_discard
);
215 cycle_t
ftrace_now(int cpu
)
219 /* Early boot up does not have a buffer yet */
220 if (!global_trace
.trace_buffer
.buffer
)
221 return trace_clock_local();
223 ts
= ring_buffer_time_stamp(global_trace
.trace_buffer
.buffer
, cpu
);
224 ring_buffer_normalize_time_stamp(global_trace
.trace_buffer
.buffer
, cpu
, &ts
);
230 * tracing_is_enabled - Show if global_trace has been disabled
232 * Shows if the global trace has been enabled or not. It uses the
233 * mirror flag "buffer_disabled" to be used in fast paths such as for
234 * the irqsoff tracer. But it may be inaccurate due to races. If you
235 * need to know the accurate state, use tracing_is_on() which is a little
236 * slower, but accurate.
238 int tracing_is_enabled(void)
241 * For quick access (irqsoff uses this in fast path), just
242 * return the mirror variable of the state of the ring buffer.
243 * It's a little racy, but we don't really care.
246 return !global_trace
.buffer_disabled
;
250 * trace_buf_size is the size in bytes that is allocated
251 * for a buffer. Note, the number of bytes is always rounded
254 * This number is purposely set to a low number of 16384.
255 * If the dump on oops happens, it will be much appreciated
256 * to not have to wait for all that output. Anyway this can be
257 * boot time and run time configurable.
259 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
261 static unsigned long trace_buf_size
= TRACE_BUF_SIZE_DEFAULT
;
263 /* trace_types holds a link list of available tracers. */
264 static struct tracer
*trace_types __read_mostly
;
267 * trace_types_lock is used to protect the trace_types list.
269 static DEFINE_MUTEX(trace_types_lock
);
272 * serialize the access of the ring buffer
274 * ring buffer serializes readers, but it is low level protection.
275 * The validity of the events (which returns by ring_buffer_peek() ..etc)
276 * are not protected by ring buffer.
278 * The content of events may become garbage if we allow other process consumes
279 * these events concurrently:
280 * A) the page of the consumed events may become a normal page
281 * (not reader page) in ring buffer, and this page will be rewrited
282 * by events producer.
283 * B) The page of the consumed events may become a page for splice_read,
284 * and this page will be returned to system.
286 * These primitives allow multi process access to different cpu ring buffer
289 * These primitives don't distinguish read-only and read-consume access.
290 * Multi read-only access are also serialized.
294 static DECLARE_RWSEM(all_cpu_access_lock
);
295 static DEFINE_PER_CPU(struct mutex
, cpu_access_lock
);
297 static inline void trace_access_lock(int cpu
)
299 if (cpu
== RING_BUFFER_ALL_CPUS
) {
300 /* gain it for accessing the whole ring buffer. */
301 down_write(&all_cpu_access_lock
);
303 /* gain it for accessing a cpu ring buffer. */
305 /* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
306 down_read(&all_cpu_access_lock
);
308 /* Secondly block other access to this @cpu ring buffer. */
309 mutex_lock(&per_cpu(cpu_access_lock
, cpu
));
313 static inline void trace_access_unlock(int cpu
)
315 if (cpu
== RING_BUFFER_ALL_CPUS
) {
316 up_write(&all_cpu_access_lock
);
318 mutex_unlock(&per_cpu(cpu_access_lock
, cpu
));
319 up_read(&all_cpu_access_lock
);
323 static inline void trace_access_lock_init(void)
327 for_each_possible_cpu(cpu
)
328 mutex_init(&per_cpu(cpu_access_lock
, cpu
));
333 static DEFINE_MUTEX(access_lock
);
335 static inline void trace_access_lock(int cpu
)
338 mutex_lock(&access_lock
);
341 static inline void trace_access_unlock(int cpu
)
344 mutex_unlock(&access_lock
);
347 static inline void trace_access_lock_init(void)
353 /* trace_flags holds trace_options default values */
354 unsigned long trace_flags
= TRACE_ITER_PRINT_PARENT
| TRACE_ITER_PRINTK
|
355 TRACE_ITER_ANNOTATE
| TRACE_ITER_CONTEXT_INFO
| TRACE_ITER_SLEEP_TIME
|
356 TRACE_ITER_GRAPH_TIME
| TRACE_ITER_RECORD_CMD
| TRACE_ITER_OVERWRITE
|
357 TRACE_ITER_IRQ_INFO
| TRACE_ITER_MARKERS
| TRACE_ITER_FUNCTION
;
359 void tracer_tracing_on(struct trace_array
*tr
)
361 if (tr
->trace_buffer
.buffer
)
362 ring_buffer_record_on(tr
->trace_buffer
.buffer
);
364 * This flag is looked at when buffers haven't been allocated
365 * yet, or by some tracers (like irqsoff), that just want to
366 * know if the ring buffer has been disabled, but it can handle
367 * races of where it gets disabled but we still do a record.
368 * As the check is in the fast path of the tracers, it is more
369 * important to be fast than accurate.
371 tr
->buffer_disabled
= 0;
372 /* Make the flag seen by readers */
377 * tracing_on - enable tracing buffers
379 * This function enables tracing buffers that may have been
380 * disabled with tracing_off.
382 void tracing_on(void)
384 tracer_tracing_on(&global_trace
);
386 EXPORT_SYMBOL_GPL(tracing_on
);
389 * __trace_puts - write a constant string into the trace buffer.
390 * @ip: The address of the caller
391 * @str: The constant string to write
392 * @size: The size of the string.
394 int __trace_puts(unsigned long ip
, const char *str
, int size
)
396 struct ring_buffer_event
*event
;
397 struct ring_buffer
*buffer
;
398 struct print_entry
*entry
;
399 unsigned long irq_flags
;
402 alloc
= sizeof(*entry
) + size
+ 2; /* possible \n added */
404 local_save_flags(irq_flags
);
405 buffer
= global_trace
.trace_buffer
.buffer
;
406 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, alloc
,
407 irq_flags
, preempt_count());
411 entry
= ring_buffer_event_data(event
);
414 memcpy(&entry
->buf
, str
, size
);
416 /* Add a newline if necessary */
417 if (entry
->buf
[size
- 1] != '\n') {
418 entry
->buf
[size
] = '\n';
419 entry
->buf
[size
+ 1] = '\0';
421 entry
->buf
[size
] = '\0';
423 __buffer_unlock_commit(buffer
, event
);
427 EXPORT_SYMBOL_GPL(__trace_puts
);
430 * __trace_bputs - write the pointer to a constant string into trace buffer
431 * @ip: The address of the caller
432 * @str: The constant string to write to the buffer to
434 int __trace_bputs(unsigned long ip
, const char *str
)
436 struct ring_buffer_event
*event
;
437 struct ring_buffer
*buffer
;
438 struct bputs_entry
*entry
;
439 unsigned long irq_flags
;
440 int size
= sizeof(struct bputs_entry
);
442 local_save_flags(irq_flags
);
443 buffer
= global_trace
.trace_buffer
.buffer
;
444 event
= trace_buffer_lock_reserve(buffer
, TRACE_BPUTS
, size
,
445 irq_flags
, preempt_count());
449 entry
= ring_buffer_event_data(event
);
453 __buffer_unlock_commit(buffer
, event
);
457 EXPORT_SYMBOL_GPL(__trace_bputs
);
459 #ifdef CONFIG_TRACER_SNAPSHOT
461 * trace_snapshot - take a snapshot of the current buffer.
463 * This causes a swap between the snapshot buffer and the current live
464 * tracing buffer. You can use this to take snapshots of the live
465 * trace when some condition is triggered, but continue to trace.
467 * Note, make sure to allocate the snapshot with either
468 * a tracing_snapshot_alloc(), or by doing it manually
469 * with: echo 1 > /sys/kernel/debug/tracing/snapshot
471 * If the snapshot buffer is not allocated, it will stop tracing.
472 * Basically making a permanent snapshot.
474 void tracing_snapshot(void)
476 struct trace_array
*tr
= &global_trace
;
477 struct tracer
*tracer
= tr
->current_trace
;
481 internal_trace_puts("*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
482 internal_trace_puts("*** snapshot is being ignored ***\n");
486 if (!tr
->allocated_snapshot
) {
487 internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n");
488 internal_trace_puts("*** stopping trace here! ***\n");
493 /* Note, snapshot can not be used when the tracer uses it */
494 if (tracer
->use_max_tr
) {
495 internal_trace_puts("*** LATENCY TRACER ACTIVE ***\n");
496 internal_trace_puts("*** Can not use snapshot (sorry) ***\n");
500 local_irq_save(flags
);
501 update_max_tr(tr
, current
, smp_processor_id());
502 local_irq_restore(flags
);
504 EXPORT_SYMBOL_GPL(tracing_snapshot
);
506 static int resize_buffer_duplicate_size(struct trace_buffer
*trace_buf
,
507 struct trace_buffer
*size_buf
, int cpu_id
);
508 static void set_buffer_entries(struct trace_buffer
*buf
, unsigned long val
);
510 static int alloc_snapshot(struct trace_array
*tr
)
514 if (!tr
->allocated_snapshot
) {
516 /* allocate spare buffer */
517 ret
= resize_buffer_duplicate_size(&tr
->max_buffer
,
518 &tr
->trace_buffer
, RING_BUFFER_ALL_CPUS
);
522 tr
->allocated_snapshot
= true;
528 void free_snapshot(struct trace_array
*tr
)
531 * We don't free the ring buffer. instead, resize it because
532 * The max_tr ring buffer has some state (e.g. ring->clock) and
533 * we want preserve it.
535 ring_buffer_resize(tr
->max_buffer
.buffer
, 1, RING_BUFFER_ALL_CPUS
);
536 set_buffer_entries(&tr
->max_buffer
, 1);
537 tracing_reset_online_cpus(&tr
->max_buffer
);
538 tr
->allocated_snapshot
= false;
542 * trace_snapshot_alloc - allocate and take a snapshot of the current buffer.
544 * This is similar to trace_snapshot(), but it will allocate the
545 * snapshot buffer if it isn't already allocated. Use this only
546 * where it is safe to sleep, as the allocation may sleep.
548 * This causes a swap between the snapshot buffer and the current live
549 * tracing buffer. You can use this to take snapshots of the live
550 * trace when some condition is triggered, but continue to trace.
552 void tracing_snapshot_alloc(void)
554 struct trace_array
*tr
= &global_trace
;
557 ret
= alloc_snapshot(tr
);
558 if (WARN_ON(ret
< 0))
563 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc
);
565 void tracing_snapshot(void)
567 WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
569 EXPORT_SYMBOL_GPL(tracing_snapshot
);
570 void tracing_snapshot_alloc(void)
575 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc
);
576 #endif /* CONFIG_TRACER_SNAPSHOT */
578 void tracer_tracing_off(struct trace_array
*tr
)
580 if (tr
->trace_buffer
.buffer
)
581 ring_buffer_record_off(tr
->trace_buffer
.buffer
);
583 * This flag is looked at when buffers haven't been allocated
584 * yet, or by some tracers (like irqsoff), that just want to
585 * know if the ring buffer has been disabled, but it can handle
586 * races of where it gets disabled but we still do a record.
587 * As the check is in the fast path of the tracers, it is more
588 * important to be fast than accurate.
590 tr
->buffer_disabled
= 1;
591 /* Make the flag seen by readers */
596 * tracing_off - turn off tracing buffers
598 * This function stops the tracing buffers from recording data.
599 * It does not disable any overhead the tracers themselves may
600 * be causing. This function simply causes all recording to
601 * the ring buffers to fail.
603 void tracing_off(void)
605 tracer_tracing_off(&global_trace
);
607 EXPORT_SYMBOL_GPL(tracing_off
);
609 void disable_trace_on_warning(void)
611 if (__disable_trace_on_warning
)
616 * tracer_tracing_is_on - show real state of ring buffer enabled
617 * @tr : the trace array to know if ring buffer is enabled
619 * Shows real state of the ring buffer if it is enabled or not.
621 int tracer_tracing_is_on(struct trace_array
*tr
)
623 if (tr
->trace_buffer
.buffer
)
624 return ring_buffer_record_is_on(tr
->trace_buffer
.buffer
);
625 return !tr
->buffer_disabled
;
629 * tracing_is_on - show state of ring buffers enabled
631 int tracing_is_on(void)
633 return tracer_tracing_is_on(&global_trace
);
635 EXPORT_SYMBOL_GPL(tracing_is_on
);
637 static int __init
set_buf_size(char *str
)
639 unsigned long buf_size
;
643 buf_size
= memparse(str
, &str
);
644 /* nr_entries can not be zero */
647 trace_buf_size
= buf_size
;
650 __setup("trace_buf_size=", set_buf_size
);
652 static int __init
set_tracing_thresh(char *str
)
654 unsigned long threshold
;
659 ret
= kstrtoul(str
, 0, &threshold
);
662 tracing_thresh
= threshold
* 1000;
665 __setup("tracing_thresh=", set_tracing_thresh
);
667 unsigned long nsecs_to_usecs(unsigned long nsecs
)
672 /* These must match the bit postions in trace_iterator_flags */
673 static const char *trace_options
[] = {
706 int in_ns
; /* is this clock in nanoseconds? */
708 { trace_clock_local
, "local", 1 },
709 { trace_clock_global
, "global", 1 },
710 { trace_clock_counter
, "counter", 0 },
711 { trace_clock_jiffies
, "uptime", 1 },
712 { trace_clock
, "perf", 1 },
719 * trace_parser_get_init - gets the buffer for trace parser
721 int trace_parser_get_init(struct trace_parser
*parser
, int size
)
723 memset(parser
, 0, sizeof(*parser
));
725 parser
->buffer
= kmalloc(size
, GFP_KERNEL
);
734 * trace_parser_put - frees the buffer for trace parser
736 void trace_parser_put(struct trace_parser
*parser
)
738 kfree(parser
->buffer
);
742 * trace_get_user - reads the user input string separated by space
743 * (matched by isspace(ch))
745 * For each string found the 'struct trace_parser' is updated,
746 * and the function returns.
748 * Returns number of bytes read.
750 * See kernel/trace/trace.h for 'struct trace_parser' details.
752 int trace_get_user(struct trace_parser
*parser
, const char __user
*ubuf
,
753 size_t cnt
, loff_t
*ppos
)
760 trace_parser_clear(parser
);
762 ret
= get_user(ch
, ubuf
++);
770 * The parser is not finished with the last write,
771 * continue reading the user input without skipping spaces.
774 /* skip white space */
775 while (cnt
&& isspace(ch
)) {
776 ret
= get_user(ch
, ubuf
++);
783 /* only spaces were written */
793 /* read the non-space input */
794 while (cnt
&& !isspace(ch
)) {
795 if (parser
->idx
< parser
->size
- 1)
796 parser
->buffer
[parser
->idx
++] = ch
;
801 ret
= get_user(ch
, ubuf
++);
808 /* We either got finished input or we have to wait for another call. */
810 parser
->buffer
[parser
->idx
] = 0;
811 parser
->cont
= false;
814 parser
->buffer
[parser
->idx
++] = ch
;
824 ssize_t
trace_seq_to_user(struct trace_seq
*s
, char __user
*ubuf
, size_t cnt
)
832 if (s
->len
<= s
->readpos
)
835 len
= s
->len
- s
->readpos
;
838 ret
= copy_to_user(ubuf
, s
->buffer
+ s
->readpos
, cnt
);
848 static ssize_t
trace_seq_to_buffer(struct trace_seq
*s
, void *buf
, size_t cnt
)
852 if (s
->len
<= s
->readpos
)
855 len
= s
->len
- s
->readpos
;
858 memcpy(buf
, s
->buffer
+ s
->readpos
, cnt
);
865 * ftrace_max_lock is used to protect the swapping of buffers
866 * when taking a max snapshot. The buffers themselves are
867 * protected by per_cpu spinlocks. But the action of the swap
868 * needs its own lock.
870 * This is defined as a arch_spinlock_t in order to help
871 * with performance when lockdep debugging is enabled.
873 * It is also used in other places outside the update_max_tr
874 * so it needs to be defined outside of the
875 * CONFIG_TRACER_MAX_TRACE.
877 static arch_spinlock_t ftrace_max_lock
=
878 (arch_spinlock_t
)__ARCH_SPIN_LOCK_UNLOCKED
;
880 unsigned long __read_mostly tracing_thresh
;
882 #ifdef CONFIG_TRACER_MAX_TRACE
883 unsigned long __read_mostly tracing_max_latency
;
886 * Copy the new maximum trace into the separate maximum-trace
887 * structure. (this way the maximum trace is permanently saved,
888 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
891 __update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
893 struct trace_buffer
*trace_buf
= &tr
->trace_buffer
;
894 struct trace_buffer
*max_buf
= &tr
->max_buffer
;
895 struct trace_array_cpu
*data
= per_cpu_ptr(trace_buf
->data
, cpu
);
896 struct trace_array_cpu
*max_data
= per_cpu_ptr(max_buf
->data
, cpu
);
899 max_buf
->time_start
= data
->preempt_timestamp
;
901 max_data
->saved_latency
= tracing_max_latency
;
902 max_data
->critical_start
= data
->critical_start
;
903 max_data
->critical_end
= data
->critical_end
;
905 memcpy(max_data
->comm
, tsk
->comm
, TASK_COMM_LEN
);
906 max_data
->pid
= tsk
->pid
;
908 * If tsk == current, then use current_uid(), as that does not use
909 * RCU. The irq tracer can be called out of RCU scope.
912 max_data
->uid
= current_uid();
914 max_data
->uid
= task_uid(tsk
);
916 max_data
->nice
= tsk
->static_prio
- 20 - MAX_RT_PRIO
;
917 max_data
->policy
= tsk
->policy
;
918 max_data
->rt_priority
= tsk
->rt_priority
;
920 /* record this tasks comm */
921 tracing_record_cmdline(tsk
);
925 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
927 * @tsk: the task with the latency
928 * @cpu: The cpu that initiated the trace.
930 * Flip the buffers between the @tr and the max_tr and record information
931 * about which task was the cause of this latency.
934 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
936 struct ring_buffer
*buf
;
941 WARN_ON_ONCE(!irqs_disabled());
943 if (!tr
->allocated_snapshot
) {
944 /* Only the nop tracer should hit this when disabling */
945 WARN_ON_ONCE(tr
->current_trace
!= &nop_trace
);
949 arch_spin_lock(&ftrace_max_lock
);
951 buf
= tr
->trace_buffer
.buffer
;
952 tr
->trace_buffer
.buffer
= tr
->max_buffer
.buffer
;
953 tr
->max_buffer
.buffer
= buf
;
955 __update_max_tr(tr
, tsk
, cpu
);
956 arch_spin_unlock(&ftrace_max_lock
);
960 * update_max_tr_single - only copy one trace over, and reset the rest
962 * @tsk - task with the latency
963 * @cpu - the cpu of the buffer to copy.
965 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
968 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
975 WARN_ON_ONCE(!irqs_disabled());
976 if (!tr
->allocated_snapshot
) {
977 /* Only the nop tracer should hit this when disabling */
978 WARN_ON_ONCE(tr
->current_trace
!= &nop_trace
);
982 arch_spin_lock(&ftrace_max_lock
);
984 ret
= ring_buffer_swap_cpu(tr
->max_buffer
.buffer
, tr
->trace_buffer
.buffer
, cpu
);
988 * We failed to swap the buffer due to a commit taking
989 * place on this CPU. We fail to record, but we reset
990 * the max trace buffer (no one writes directly to it)
991 * and flag that it failed.
993 trace_array_printk_buf(tr
->max_buffer
.buffer
, _THIS_IP_
,
994 "Failed to swap buffers due to commit in progress\n");
997 WARN_ON_ONCE(ret
&& ret
!= -EAGAIN
&& ret
!= -EBUSY
);
999 __update_max_tr(tr
, tsk
, cpu
);
1000 arch_spin_unlock(&ftrace_max_lock
);
1002 #endif /* CONFIG_TRACER_MAX_TRACE */
1004 static void default_wait_pipe(struct trace_iterator
*iter
)
1006 /* Iterators are static, they should be filled or empty */
1007 if (trace_buffer_iter(iter
, iter
->cpu_file
))
1010 ring_buffer_wait(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
1013 #ifdef CONFIG_FTRACE_STARTUP_TEST
1014 static int run_tracer_selftest(struct tracer
*type
)
1016 struct trace_array
*tr
= &global_trace
;
1017 struct tracer
*saved_tracer
= tr
->current_trace
;
1020 if (!type
->selftest
|| tracing_selftest_disabled
)
1024 * Run a selftest on this tracer.
1025 * Here we reset the trace buffer, and set the current
1026 * tracer to be this tracer. The tracer can then run some
1027 * internal tracing to verify that everything is in order.
1028 * If we fail, we do not register this tracer.
1030 tracing_reset_online_cpus(&tr
->trace_buffer
);
1032 tr
->current_trace
= type
;
1034 #ifdef CONFIG_TRACER_MAX_TRACE
1035 if (type
->use_max_tr
) {
1036 /* If we expanded the buffers, make sure the max is expanded too */
1037 if (ring_buffer_expanded
)
1038 ring_buffer_resize(tr
->max_buffer
.buffer
, trace_buf_size
,
1039 RING_BUFFER_ALL_CPUS
);
1040 tr
->allocated_snapshot
= true;
1044 /* the test is responsible for initializing and enabling */
1045 pr_info("Testing tracer %s: ", type
->name
);
1046 ret
= type
->selftest(type
, tr
);
1047 /* the test is responsible for resetting too */
1048 tr
->current_trace
= saved_tracer
;
1050 printk(KERN_CONT
"FAILED!\n");
1051 /* Add the warning after printing 'FAILED' */
1055 /* Only reset on passing, to avoid touching corrupted buffers */
1056 tracing_reset_online_cpus(&tr
->trace_buffer
);
1058 #ifdef CONFIG_TRACER_MAX_TRACE
1059 if (type
->use_max_tr
) {
1060 tr
->allocated_snapshot
= false;
1062 /* Shrink the max buffer again */
1063 if (ring_buffer_expanded
)
1064 ring_buffer_resize(tr
->max_buffer
.buffer
, 1,
1065 RING_BUFFER_ALL_CPUS
);
1069 printk(KERN_CONT
"PASSED\n");
1073 static inline int run_tracer_selftest(struct tracer
*type
)
1077 #endif /* CONFIG_FTRACE_STARTUP_TEST */
1080 * register_tracer - register a tracer with the ftrace system.
1081 * @type - the plugin for the tracer
1083 * Register a new plugin tracer.
1085 int register_tracer(struct tracer
*type
)
1091 pr_info("Tracer must have a name\n");
1095 if (strlen(type
->name
) >= MAX_TRACER_SIZE
) {
1096 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE
);
1100 mutex_lock(&trace_types_lock
);
1102 tracing_selftest_running
= true;
1104 for (t
= trace_types
; t
; t
= t
->next
) {
1105 if (strcmp(type
->name
, t
->name
) == 0) {
1107 pr_info("Tracer %s already registered\n",
1114 if (!type
->set_flag
)
1115 type
->set_flag
= &dummy_set_flag
;
1117 type
->flags
= &dummy_tracer_flags
;
1119 if (!type
->flags
->opts
)
1120 type
->flags
->opts
= dummy_tracer_opt
;
1121 if (!type
->wait_pipe
)
1122 type
->wait_pipe
= default_wait_pipe
;
1124 ret
= run_tracer_selftest(type
);
1128 type
->next
= trace_types
;
1132 tracing_selftest_running
= false;
1133 mutex_unlock(&trace_types_lock
);
1135 if (ret
|| !default_bootup_tracer
)
1138 if (strncmp(default_bootup_tracer
, type
->name
, MAX_TRACER_SIZE
))
1141 printk(KERN_INFO
"Starting tracer '%s'\n", type
->name
);
1142 /* Do we want this tracer to start on bootup? */
1143 tracing_set_tracer(type
->name
);
1144 default_bootup_tracer
= NULL
;
1145 /* disable other selftests, since this will break it. */
1146 tracing_selftest_disabled
= true;
1147 #ifdef CONFIG_FTRACE_STARTUP_TEST
1148 printk(KERN_INFO
"Disabling FTRACE selftests due to running tracer '%s'\n",
1156 void tracing_reset(struct trace_buffer
*buf
, int cpu
)
1158 struct ring_buffer
*buffer
= buf
->buffer
;
1163 ring_buffer_record_disable(buffer
);
1165 /* Make sure all commits have finished */
1166 synchronize_sched();
1167 ring_buffer_reset_cpu(buffer
, cpu
);
1169 ring_buffer_record_enable(buffer
);
1172 void tracing_reset_online_cpus(struct trace_buffer
*buf
)
1174 struct ring_buffer
*buffer
= buf
->buffer
;
1180 ring_buffer_record_disable(buffer
);
1182 /* Make sure all commits have finished */
1183 synchronize_sched();
1185 buf
->time_start
= ftrace_now(buf
->cpu
);
1187 for_each_online_cpu(cpu
)
1188 ring_buffer_reset_cpu(buffer
, cpu
);
1190 ring_buffer_record_enable(buffer
);
1193 void tracing_reset_current(int cpu
)
1195 tracing_reset(&global_trace
.trace_buffer
, cpu
);
1198 void tracing_reset_all_online_cpus(void)
1200 struct trace_array
*tr
;
1202 mutex_lock(&trace_types_lock
);
1203 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
1204 tracing_reset_online_cpus(&tr
->trace_buffer
);
1205 #ifdef CONFIG_TRACER_MAX_TRACE
1206 tracing_reset_online_cpus(&tr
->max_buffer
);
1209 mutex_unlock(&trace_types_lock
);
1212 #define SAVED_CMDLINES 128
1213 #define NO_CMDLINE_MAP UINT_MAX
1214 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
1215 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
1216 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
1217 static int cmdline_idx
;
1218 static arch_spinlock_t trace_cmdline_lock
= __ARCH_SPIN_LOCK_UNLOCKED
;
1220 /* temporary disable recording */
1221 static atomic_t trace_record_cmdline_disabled __read_mostly
;
1223 static void trace_init_cmdlines(void)
1225 memset(&map_pid_to_cmdline
, NO_CMDLINE_MAP
, sizeof(map_pid_to_cmdline
));
1226 memset(&map_cmdline_to_pid
, NO_CMDLINE_MAP
, sizeof(map_cmdline_to_pid
));
1230 int is_tracing_stopped(void)
1232 return global_trace
.stop_count
;
1236 * ftrace_off_permanent - disable all ftrace code permanently
1238 * This should only be called when a serious anomally has
1239 * been detected. This will turn off the function tracing,
1240 * ring buffers, and other tracing utilites. It takes no
1241 * locks and can be called from any context.
1243 void ftrace_off_permanent(void)
1245 tracing_disabled
= 1;
1247 tracing_off_permanent();
1251 * tracing_start - quick start of the tracer
1253 * If tracing is enabled but was stopped by tracing_stop,
1254 * this will start the tracer back up.
1256 void tracing_start(void)
1258 struct ring_buffer
*buffer
;
1259 unsigned long flags
;
1261 if (tracing_disabled
)
1264 raw_spin_lock_irqsave(&global_trace
.start_lock
, flags
);
1265 if (--global_trace
.stop_count
) {
1266 if (global_trace
.stop_count
< 0) {
1267 /* Someone screwed up their debugging */
1269 global_trace
.stop_count
= 0;
1274 /* Prevent the buffers from switching */
1275 arch_spin_lock(&ftrace_max_lock
);
1277 buffer
= global_trace
.trace_buffer
.buffer
;
1279 ring_buffer_record_enable(buffer
);
1281 #ifdef CONFIG_TRACER_MAX_TRACE
1282 buffer
= global_trace
.max_buffer
.buffer
;
1284 ring_buffer_record_enable(buffer
);
1287 arch_spin_unlock(&ftrace_max_lock
);
1291 raw_spin_unlock_irqrestore(&global_trace
.start_lock
, flags
);
1294 static void tracing_start_tr(struct trace_array
*tr
)
1296 struct ring_buffer
*buffer
;
1297 unsigned long flags
;
1299 if (tracing_disabled
)
1302 /* If global, we need to also start the max tracer */
1303 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
1304 return tracing_start();
1306 raw_spin_lock_irqsave(&tr
->start_lock
, flags
);
1308 if (--tr
->stop_count
) {
1309 if (tr
->stop_count
< 0) {
1310 /* Someone screwed up their debugging */
1317 buffer
= tr
->trace_buffer
.buffer
;
1319 ring_buffer_record_enable(buffer
);
1322 raw_spin_unlock_irqrestore(&tr
->start_lock
, flags
);
1326 * tracing_stop - quick stop of the tracer
1328 * Light weight way to stop tracing. Use in conjunction with
1331 void tracing_stop(void)
1333 struct ring_buffer
*buffer
;
1334 unsigned long flags
;
1337 raw_spin_lock_irqsave(&global_trace
.start_lock
, flags
);
1338 if (global_trace
.stop_count
++)
1341 /* Prevent the buffers from switching */
1342 arch_spin_lock(&ftrace_max_lock
);
1344 buffer
= global_trace
.trace_buffer
.buffer
;
1346 ring_buffer_record_disable(buffer
);
1348 #ifdef CONFIG_TRACER_MAX_TRACE
1349 buffer
= global_trace
.max_buffer
.buffer
;
1351 ring_buffer_record_disable(buffer
);
1354 arch_spin_unlock(&ftrace_max_lock
);
1357 raw_spin_unlock_irqrestore(&global_trace
.start_lock
, flags
);
1360 static void tracing_stop_tr(struct trace_array
*tr
)
1362 struct ring_buffer
*buffer
;
1363 unsigned long flags
;
1365 /* If global, we need to also stop the max tracer */
1366 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
1367 return tracing_stop();
1369 raw_spin_lock_irqsave(&tr
->start_lock
, flags
);
1370 if (tr
->stop_count
++)
1373 buffer
= tr
->trace_buffer
.buffer
;
1375 ring_buffer_record_disable(buffer
);
1378 raw_spin_unlock_irqrestore(&tr
->start_lock
, flags
);
1381 void trace_stop_cmdline_recording(void);
1383 static void trace_save_cmdline(struct task_struct
*tsk
)
1387 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
1391 * It's not the end of the world if we don't get
1392 * the lock, but we also don't want to spin
1393 * nor do we want to disable interrupts,
1394 * so if we miss here, then better luck next time.
1396 if (!arch_spin_trylock(&trace_cmdline_lock
))
1399 idx
= map_pid_to_cmdline
[tsk
->pid
];
1400 if (idx
== NO_CMDLINE_MAP
) {
1401 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
1404 * Check whether the cmdline buffer at idx has a pid
1405 * mapped. We are going to overwrite that entry so we
1406 * need to clear the map_pid_to_cmdline. Otherwise we
1407 * would read the new comm for the old pid.
1409 pid
= map_cmdline_to_pid
[idx
];
1410 if (pid
!= NO_CMDLINE_MAP
)
1411 map_pid_to_cmdline
[pid
] = NO_CMDLINE_MAP
;
1413 map_cmdline_to_pid
[idx
] = tsk
->pid
;
1414 map_pid_to_cmdline
[tsk
->pid
] = idx
;
1419 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
1421 arch_spin_unlock(&trace_cmdline_lock
);
1424 void trace_find_cmdline(int pid
, char comm
[])
1429 strcpy(comm
, "<idle>");
1433 if (WARN_ON_ONCE(pid
< 0)) {
1434 strcpy(comm
, "<XXX>");
1438 if (pid
> PID_MAX_DEFAULT
) {
1439 strcpy(comm
, "<...>");
1444 arch_spin_lock(&trace_cmdline_lock
);
1445 map
= map_pid_to_cmdline
[pid
];
1446 if (map
!= NO_CMDLINE_MAP
)
1447 strcpy(comm
, saved_cmdlines
[map
]);
1449 strcpy(comm
, "<...>");
1451 arch_spin_unlock(&trace_cmdline_lock
);
1455 void tracing_record_cmdline(struct task_struct
*tsk
)
1457 if (atomic_read(&trace_record_cmdline_disabled
) || !tracing_is_on())
1460 if (!__this_cpu_read(trace_cmdline_save
))
1463 __this_cpu_write(trace_cmdline_save
, false);
1465 trace_save_cmdline(tsk
);
1469 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
,
1472 struct task_struct
*tsk
= current
;
1474 entry
->preempt_count
= pc
& 0xff;
1475 entry
->pid
= (tsk
) ? tsk
->pid
: 0;
1477 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1478 (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
1480 TRACE_FLAG_IRQS_NOSUPPORT
|
1482 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
1483 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
1484 (need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0);
1486 EXPORT_SYMBOL_GPL(tracing_generic_entry_update
);
1488 struct ring_buffer_event
*
1489 trace_buffer_lock_reserve(struct ring_buffer
*buffer
,
1492 unsigned long flags
, int pc
)
1494 struct ring_buffer_event
*event
;
1496 event
= ring_buffer_lock_reserve(buffer
, len
);
1497 if (event
!= NULL
) {
1498 struct trace_entry
*ent
= ring_buffer_event_data(event
);
1500 tracing_generic_entry_update(ent
, flags
, pc
);
1508 __buffer_unlock_commit(struct ring_buffer
*buffer
, struct ring_buffer_event
*event
)
1510 __this_cpu_write(trace_cmdline_save
, true);
1511 ring_buffer_unlock_commit(buffer
, event
);
1515 __trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1516 struct ring_buffer_event
*event
,
1517 unsigned long flags
, int pc
)
1519 __buffer_unlock_commit(buffer
, event
);
1521 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1522 ftrace_trace_userstack(buffer
, flags
, pc
);
1525 void trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1526 struct ring_buffer_event
*event
,
1527 unsigned long flags
, int pc
)
1529 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
);
1531 EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit
);
1533 struct ring_buffer_event
*
1534 trace_event_buffer_lock_reserve(struct ring_buffer
**current_rb
,
1535 struct ftrace_event_file
*ftrace_file
,
1536 int type
, unsigned long len
,
1537 unsigned long flags
, int pc
)
1539 *current_rb
= ftrace_file
->tr
->trace_buffer
.buffer
;
1540 return trace_buffer_lock_reserve(*current_rb
,
1541 type
, len
, flags
, pc
);
1543 EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve
);
1545 struct ring_buffer_event
*
1546 trace_current_buffer_lock_reserve(struct ring_buffer
**current_rb
,
1547 int type
, unsigned long len
,
1548 unsigned long flags
, int pc
)
1550 *current_rb
= global_trace
.trace_buffer
.buffer
;
1551 return trace_buffer_lock_reserve(*current_rb
,
1552 type
, len
, flags
, pc
);
1554 EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve
);
1556 void trace_current_buffer_unlock_commit(struct ring_buffer
*buffer
,
1557 struct ring_buffer_event
*event
,
1558 unsigned long flags
, int pc
)
1560 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
);
1562 EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit
);
1564 void trace_buffer_unlock_commit_regs(struct ring_buffer
*buffer
,
1565 struct ring_buffer_event
*event
,
1566 unsigned long flags
, int pc
,
1567 struct pt_regs
*regs
)
1569 __buffer_unlock_commit(buffer
, event
);
1571 ftrace_trace_stack_regs(buffer
, flags
, 0, pc
, regs
);
1572 ftrace_trace_userstack(buffer
, flags
, pc
);
1574 EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit_regs
);
1576 void trace_current_buffer_discard_commit(struct ring_buffer
*buffer
,
1577 struct ring_buffer_event
*event
)
1579 ring_buffer_discard_commit(buffer
, event
);
1581 EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit
);
1584 trace_function(struct trace_array
*tr
,
1585 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
1588 struct ftrace_event_call
*call
= &event_function
;
1589 struct ring_buffer
*buffer
= tr
->trace_buffer
.buffer
;
1590 struct ring_buffer_event
*event
;
1591 struct ftrace_entry
*entry
;
1593 /* If we are reading the ring buffer, don't trace */
1594 if (unlikely(__this_cpu_read(ftrace_cpu_disabled
)))
1597 event
= trace_buffer_lock_reserve(buffer
, TRACE_FN
, sizeof(*entry
),
1601 entry
= ring_buffer_event_data(event
);
1603 entry
->parent_ip
= parent_ip
;
1605 if (!filter_check_discard(call
, entry
, buffer
, event
))
1606 __buffer_unlock_commit(buffer
, event
);
1610 ftrace(struct trace_array
*tr
, struct trace_array_cpu
*data
,
1611 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
1614 if (likely(!atomic_read(&data
->disabled
)))
1615 trace_function(tr
, ip
, parent_ip
, flags
, pc
);
1618 #ifdef CONFIG_STACKTRACE
1620 #define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
1621 struct ftrace_stack
{
1622 unsigned long calls
[FTRACE_STACK_MAX_ENTRIES
];
1625 static DEFINE_PER_CPU(struct ftrace_stack
, ftrace_stack
);
1626 static DEFINE_PER_CPU(int, ftrace_stack_reserve
);
1628 static void __ftrace_trace_stack(struct ring_buffer
*buffer
,
1629 unsigned long flags
,
1630 int skip
, int pc
, struct pt_regs
*regs
)
1632 struct ftrace_event_call
*call
= &event_kernel_stack
;
1633 struct ring_buffer_event
*event
;
1634 struct stack_entry
*entry
;
1635 struct stack_trace trace
;
1637 int size
= FTRACE_STACK_ENTRIES
;
1639 trace
.nr_entries
= 0;
1643 * Since events can happen in NMIs there's no safe way to
1644 * use the per cpu ftrace_stacks. We reserve it and if an interrupt
1645 * or NMI comes in, it will just have to use the default
1646 * FTRACE_STACK_SIZE.
1648 preempt_disable_notrace();
1650 use_stack
= __this_cpu_inc_return(ftrace_stack_reserve
);
1652 * We don't need any atomic variables, just a barrier.
1653 * If an interrupt comes in, we don't care, because it would
1654 * have exited and put the counter back to what we want.
1655 * We just need a barrier to keep gcc from moving things
1659 if (use_stack
== 1) {
1660 trace
.entries
= &__get_cpu_var(ftrace_stack
).calls
[0];
1661 trace
.max_entries
= FTRACE_STACK_MAX_ENTRIES
;
1664 save_stack_trace_regs(regs
, &trace
);
1666 save_stack_trace(&trace
);
1668 if (trace
.nr_entries
> size
)
1669 size
= trace
.nr_entries
;
1671 /* From now on, use_stack is a boolean */
1674 size
*= sizeof(unsigned long);
1676 event
= trace_buffer_lock_reserve(buffer
, TRACE_STACK
,
1677 sizeof(*entry
) + size
, flags
, pc
);
1680 entry
= ring_buffer_event_data(event
);
1682 memset(&entry
->caller
, 0, size
);
1685 memcpy(&entry
->caller
, trace
.entries
,
1686 trace
.nr_entries
* sizeof(unsigned long));
1688 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1689 trace
.entries
= entry
->caller
;
1691 save_stack_trace_regs(regs
, &trace
);
1693 save_stack_trace(&trace
);
1696 entry
->size
= trace
.nr_entries
;
1698 if (!filter_check_discard(call
, entry
, buffer
, event
))
1699 __buffer_unlock_commit(buffer
, event
);
1702 /* Again, don't let gcc optimize things here */
1704 __this_cpu_dec(ftrace_stack_reserve
);
1705 preempt_enable_notrace();
1709 void ftrace_trace_stack_regs(struct ring_buffer
*buffer
, unsigned long flags
,
1710 int skip
, int pc
, struct pt_regs
*regs
)
1712 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1715 __ftrace_trace_stack(buffer
, flags
, skip
, pc
, regs
);
1718 void ftrace_trace_stack(struct ring_buffer
*buffer
, unsigned long flags
,
1721 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1724 __ftrace_trace_stack(buffer
, flags
, skip
, pc
, NULL
);
1727 void __trace_stack(struct trace_array
*tr
, unsigned long flags
, int skip
,
1730 __ftrace_trace_stack(tr
->trace_buffer
.buffer
, flags
, skip
, pc
, NULL
);
1734 * trace_dump_stack - record a stack back trace in the trace buffer
1735 * @skip: Number of functions to skip (helper handlers)
1737 void trace_dump_stack(int skip
)
1739 unsigned long flags
;
1741 if (tracing_disabled
|| tracing_selftest_running
)
1744 local_save_flags(flags
);
1747 * Skip 3 more, seems to get us at the caller of
1751 __ftrace_trace_stack(global_trace
.trace_buffer
.buffer
,
1752 flags
, skip
, preempt_count(), NULL
);
1755 static DEFINE_PER_CPU(int, user_stack_count
);
1758 ftrace_trace_userstack(struct ring_buffer
*buffer
, unsigned long flags
, int pc
)
1760 struct ftrace_event_call
*call
= &event_user_stack
;
1761 struct ring_buffer_event
*event
;
1762 struct userstack_entry
*entry
;
1763 struct stack_trace trace
;
1765 if (!(trace_flags
& TRACE_ITER_USERSTACKTRACE
))
1769 * NMIs can not handle page faults, even with fix ups.
1770 * The save user stack can (and often does) fault.
1772 if (unlikely(in_nmi()))
1776 * prevent recursion, since the user stack tracing may
1777 * trigger other kernel events.
1780 if (__this_cpu_read(user_stack_count
))
1783 __this_cpu_inc(user_stack_count
);
1785 event
= trace_buffer_lock_reserve(buffer
, TRACE_USER_STACK
,
1786 sizeof(*entry
), flags
, pc
);
1788 goto out_drop_count
;
1789 entry
= ring_buffer_event_data(event
);
1791 entry
->tgid
= current
->tgid
;
1792 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
1794 trace
.nr_entries
= 0;
1795 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1797 trace
.entries
= entry
->caller
;
1799 save_stack_trace_user(&trace
);
1800 if (!filter_check_discard(call
, entry
, buffer
, event
))
1801 __buffer_unlock_commit(buffer
, event
);
1804 __this_cpu_dec(user_stack_count
);
1810 static void __trace_userstack(struct trace_array
*tr
, unsigned long flags
)
1812 ftrace_trace_userstack(tr
, flags
, preempt_count());
1816 #endif /* CONFIG_STACKTRACE */
1818 /* created for use with alloc_percpu */
1819 struct trace_buffer_struct
{
1820 char buffer
[TRACE_BUF_SIZE
];
1823 static struct trace_buffer_struct
*trace_percpu_buffer
;
1824 static struct trace_buffer_struct
*trace_percpu_sirq_buffer
;
1825 static struct trace_buffer_struct
*trace_percpu_irq_buffer
;
1826 static struct trace_buffer_struct
*trace_percpu_nmi_buffer
;
1829 * The buffer used is dependent on the context. There is a per cpu
1830 * buffer for normal context, softirq contex, hard irq context and
1831 * for NMI context. Thise allows for lockless recording.
1833 * Note, if the buffers failed to be allocated, then this returns NULL
1835 static char *get_trace_buf(void)
1837 struct trace_buffer_struct
*percpu_buffer
;
1840 * If we have allocated per cpu buffers, then we do not
1841 * need to do any locking.
1844 percpu_buffer
= trace_percpu_nmi_buffer
;
1846 percpu_buffer
= trace_percpu_irq_buffer
;
1847 else if (in_softirq())
1848 percpu_buffer
= trace_percpu_sirq_buffer
;
1850 percpu_buffer
= trace_percpu_buffer
;
1855 return this_cpu_ptr(&percpu_buffer
->buffer
[0]);
1858 static int alloc_percpu_trace_buffer(void)
1860 struct trace_buffer_struct
*buffers
;
1861 struct trace_buffer_struct
*sirq_buffers
;
1862 struct trace_buffer_struct
*irq_buffers
;
1863 struct trace_buffer_struct
*nmi_buffers
;
1865 buffers
= alloc_percpu(struct trace_buffer_struct
);
1869 sirq_buffers
= alloc_percpu(struct trace_buffer_struct
);
1873 irq_buffers
= alloc_percpu(struct trace_buffer_struct
);
1877 nmi_buffers
= alloc_percpu(struct trace_buffer_struct
);
1881 trace_percpu_buffer
= buffers
;
1882 trace_percpu_sirq_buffer
= sirq_buffers
;
1883 trace_percpu_irq_buffer
= irq_buffers
;
1884 trace_percpu_nmi_buffer
= nmi_buffers
;
1889 free_percpu(irq_buffers
);
1891 free_percpu(sirq_buffers
);
1893 free_percpu(buffers
);
1895 WARN(1, "Could not allocate percpu trace_printk buffer");
1899 static int buffers_allocated
;
1901 void trace_printk_init_buffers(void)
1903 if (buffers_allocated
)
1906 if (alloc_percpu_trace_buffer())
1909 pr_info("ftrace: Allocated trace_printk buffers\n");
1911 /* Expand the buffers to set size */
1912 tracing_update_buffers();
1914 buffers_allocated
= 1;
1917 * trace_printk_init_buffers() can be called by modules.
1918 * If that happens, then we need to start cmdline recording
1919 * directly here. If the global_trace.buffer is already
1920 * allocated here, then this was called by module code.
1922 if (global_trace
.trace_buffer
.buffer
)
1923 tracing_start_cmdline_record();
1926 void trace_printk_start_comm(void)
1928 /* Start tracing comms if trace printk is set */
1929 if (!buffers_allocated
)
1931 tracing_start_cmdline_record();
1934 static void trace_printk_start_stop_comm(int enabled
)
1936 if (!buffers_allocated
)
1940 tracing_start_cmdline_record();
1942 tracing_stop_cmdline_record();
1946 * trace_vbprintk - write binary msg to tracing buffer
1949 int trace_vbprintk(unsigned long ip
, const char *fmt
, va_list args
)
1951 struct ftrace_event_call
*call
= &event_bprint
;
1952 struct ring_buffer_event
*event
;
1953 struct ring_buffer
*buffer
;
1954 struct trace_array
*tr
= &global_trace
;
1955 struct bprint_entry
*entry
;
1956 unsigned long flags
;
1958 int len
= 0, size
, pc
;
1960 if (unlikely(tracing_selftest_running
|| tracing_disabled
))
1963 /* Don't pollute graph traces with trace_vprintk internals */
1964 pause_graph_tracing();
1966 pc
= preempt_count();
1967 preempt_disable_notrace();
1969 tbuffer
= get_trace_buf();
1975 len
= vbin_printf((u32
*)tbuffer
, TRACE_BUF_SIZE
/sizeof(int), fmt
, args
);
1977 if (len
> TRACE_BUF_SIZE
/sizeof(int) || len
< 0)
1980 local_save_flags(flags
);
1981 size
= sizeof(*entry
) + sizeof(u32
) * len
;
1982 buffer
= tr
->trace_buffer
.buffer
;
1983 event
= trace_buffer_lock_reserve(buffer
, TRACE_BPRINT
, size
,
1987 entry
= ring_buffer_event_data(event
);
1991 memcpy(entry
->buf
, tbuffer
, sizeof(u32
) * len
);
1992 if (!filter_check_discard(call
, entry
, buffer
, event
)) {
1993 __buffer_unlock_commit(buffer
, event
);
1994 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1998 preempt_enable_notrace();
1999 unpause_graph_tracing();
2003 EXPORT_SYMBOL_GPL(trace_vbprintk
);
2006 __trace_array_vprintk(struct ring_buffer
*buffer
,
2007 unsigned long ip
, const char *fmt
, va_list args
)
2009 struct ftrace_event_call
*call
= &event_print
;
2010 struct ring_buffer_event
*event
;
2011 int len
= 0, size
, pc
;
2012 struct print_entry
*entry
;
2013 unsigned long flags
;
2016 if (tracing_disabled
|| tracing_selftest_running
)
2019 /* Don't pollute graph traces with trace_vprintk internals */
2020 pause_graph_tracing();
2022 pc
= preempt_count();
2023 preempt_disable_notrace();
2026 tbuffer
= get_trace_buf();
2032 len
= vsnprintf(tbuffer
, TRACE_BUF_SIZE
, fmt
, args
);
2033 if (len
> TRACE_BUF_SIZE
)
2036 local_save_flags(flags
);
2037 size
= sizeof(*entry
) + len
+ 1;
2038 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, size
,
2042 entry
= ring_buffer_event_data(event
);
2045 memcpy(&entry
->buf
, tbuffer
, len
);
2046 entry
->buf
[len
] = '\0';
2047 if (!filter_check_discard(call
, entry
, buffer
, event
)) {
2048 __buffer_unlock_commit(buffer
, event
);
2049 ftrace_trace_stack(buffer
, flags
, 6, pc
);
2052 preempt_enable_notrace();
2053 unpause_graph_tracing();
2058 int trace_array_vprintk(struct trace_array
*tr
,
2059 unsigned long ip
, const char *fmt
, va_list args
)
2061 return __trace_array_vprintk(tr
->trace_buffer
.buffer
, ip
, fmt
, args
);
2064 int trace_array_printk(struct trace_array
*tr
,
2065 unsigned long ip
, const char *fmt
, ...)
2070 if (!(trace_flags
& TRACE_ITER_PRINTK
))
2074 ret
= trace_array_vprintk(tr
, ip
, fmt
, ap
);
2079 int trace_array_printk_buf(struct ring_buffer
*buffer
,
2080 unsigned long ip
, const char *fmt
, ...)
2085 if (!(trace_flags
& TRACE_ITER_PRINTK
))
2089 ret
= __trace_array_vprintk(buffer
, ip
, fmt
, ap
);
2094 int trace_vprintk(unsigned long ip
, const char *fmt
, va_list args
)
2096 return trace_array_vprintk(&global_trace
, ip
, fmt
, args
);
2098 EXPORT_SYMBOL_GPL(trace_vprintk
);
2100 static void trace_iterator_increment(struct trace_iterator
*iter
)
2102 struct ring_buffer_iter
*buf_iter
= trace_buffer_iter(iter
, iter
->cpu
);
2106 ring_buffer_read(buf_iter
, NULL
);
2109 static struct trace_entry
*
2110 peek_next_entry(struct trace_iterator
*iter
, int cpu
, u64
*ts
,
2111 unsigned long *lost_events
)
2113 struct ring_buffer_event
*event
;
2114 struct ring_buffer_iter
*buf_iter
= trace_buffer_iter(iter
, cpu
);
2117 event
= ring_buffer_iter_peek(buf_iter
, ts
);
2119 event
= ring_buffer_peek(iter
->trace_buffer
->buffer
, cpu
, ts
,
2123 iter
->ent_size
= ring_buffer_event_length(event
);
2124 return ring_buffer_event_data(event
);
2130 static struct trace_entry
*
2131 __find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
,
2132 unsigned long *missing_events
, u64
*ent_ts
)
2134 struct ring_buffer
*buffer
= iter
->trace_buffer
->buffer
;
2135 struct trace_entry
*ent
, *next
= NULL
;
2136 unsigned long lost_events
= 0, next_lost
= 0;
2137 int cpu_file
= iter
->cpu_file
;
2138 u64 next_ts
= 0, ts
;
2144 * If we are in a per_cpu trace file, don't bother by iterating over
2145 * all cpu and peek directly.
2147 if (cpu_file
> RING_BUFFER_ALL_CPUS
) {
2148 if (ring_buffer_empty_cpu(buffer
, cpu_file
))
2150 ent
= peek_next_entry(iter
, cpu_file
, ent_ts
, missing_events
);
2152 *ent_cpu
= cpu_file
;
2157 for_each_tracing_cpu(cpu
) {
2159 if (ring_buffer_empty_cpu(buffer
, cpu
))
2162 ent
= peek_next_entry(iter
, cpu
, &ts
, &lost_events
);
2165 * Pick the entry with the smallest timestamp:
2167 if (ent
&& (!next
|| ts
< next_ts
)) {
2171 next_lost
= lost_events
;
2172 next_size
= iter
->ent_size
;
2176 iter
->ent_size
= next_size
;
2179 *ent_cpu
= next_cpu
;
2185 *missing_events
= next_lost
;
2190 /* Find the next real entry, without updating the iterator itself */
2191 struct trace_entry
*trace_find_next_entry(struct trace_iterator
*iter
,
2192 int *ent_cpu
, u64
*ent_ts
)
2194 return __find_next_entry(iter
, ent_cpu
, NULL
, ent_ts
);
2197 /* Find the next real entry, and increment the iterator to the next entry */
2198 void *trace_find_next_entry_inc(struct trace_iterator
*iter
)
2200 iter
->ent
= __find_next_entry(iter
, &iter
->cpu
,
2201 &iter
->lost_events
, &iter
->ts
);
2204 trace_iterator_increment(iter
);
2206 return iter
->ent
? iter
: NULL
;
2209 static void trace_consume(struct trace_iterator
*iter
)
2211 ring_buffer_consume(iter
->trace_buffer
->buffer
, iter
->cpu
, &iter
->ts
,
2212 &iter
->lost_events
);
2215 static void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
2217 struct trace_iterator
*iter
= m
->private;
2221 WARN_ON_ONCE(iter
->leftover
);
2225 /* can't go backwards */
2230 ent
= trace_find_next_entry_inc(iter
);
2234 while (ent
&& iter
->idx
< i
)
2235 ent
= trace_find_next_entry_inc(iter
);
2242 void tracing_iter_reset(struct trace_iterator
*iter
, int cpu
)
2244 struct ring_buffer_event
*event
;
2245 struct ring_buffer_iter
*buf_iter
;
2246 unsigned long entries
= 0;
2249 per_cpu_ptr(iter
->trace_buffer
->data
, cpu
)->skipped_entries
= 0;
2251 buf_iter
= trace_buffer_iter(iter
, cpu
);
2255 ring_buffer_iter_reset(buf_iter
);
2258 * We could have the case with the max latency tracers
2259 * that a reset never took place on a cpu. This is evident
2260 * by the timestamp being before the start of the buffer.
2262 while ((event
= ring_buffer_iter_peek(buf_iter
, &ts
))) {
2263 if (ts
>= iter
->trace_buffer
->time_start
)
2266 ring_buffer_read(buf_iter
, NULL
);
2269 per_cpu_ptr(iter
->trace_buffer
->data
, cpu
)->skipped_entries
= entries
;
2273 * The current tracer is copied to avoid a global locking
2276 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
2278 struct trace_iterator
*iter
= m
->private;
2279 struct trace_array
*tr
= iter
->tr
;
2280 int cpu_file
= iter
->cpu_file
;
2286 * copy the tracer to avoid using a global lock all around.
2287 * iter->trace is a copy of current_trace, the pointer to the
2288 * name may be used instead of a strcmp(), as iter->trace->name
2289 * will point to the same string as current_trace->name.
2291 mutex_lock(&trace_types_lock
);
2292 if (unlikely(tr
->current_trace
&& iter
->trace
->name
!= tr
->current_trace
->name
))
2293 *iter
->trace
= *tr
->current_trace
;
2294 mutex_unlock(&trace_types_lock
);
2296 #ifdef CONFIG_TRACER_MAX_TRACE
2297 if (iter
->snapshot
&& iter
->trace
->use_max_tr
)
2298 return ERR_PTR(-EBUSY
);
2301 if (!iter
->snapshot
)
2302 atomic_inc(&trace_record_cmdline_disabled
);
2304 if (*pos
!= iter
->pos
) {
2309 if (cpu_file
== RING_BUFFER_ALL_CPUS
) {
2310 for_each_tracing_cpu(cpu
)
2311 tracing_iter_reset(iter
, cpu
);
2313 tracing_iter_reset(iter
, cpu_file
);
2316 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
2321 * If we overflowed the seq_file before, then we want
2322 * to just reuse the trace_seq buffer again.
2328 p
= s_next(m
, p
, &l
);
2332 trace_event_read_lock();
2333 trace_access_lock(cpu_file
);
2337 static void s_stop(struct seq_file
*m
, void *p
)
2339 struct trace_iterator
*iter
= m
->private;
2341 #ifdef CONFIG_TRACER_MAX_TRACE
2342 if (iter
->snapshot
&& iter
->trace
->use_max_tr
)
2346 if (!iter
->snapshot
)
2347 atomic_dec(&trace_record_cmdline_disabled
);
2349 trace_access_unlock(iter
->cpu_file
);
2350 trace_event_read_unlock();
2354 get_total_entries(struct trace_buffer
*buf
,
2355 unsigned long *total
, unsigned long *entries
)
2357 unsigned long count
;
2363 for_each_tracing_cpu(cpu
) {
2364 count
= ring_buffer_entries_cpu(buf
->buffer
, cpu
);
2366 * If this buffer has skipped entries, then we hold all
2367 * entries for the trace and we need to ignore the
2368 * ones before the time stamp.
2370 if (per_cpu_ptr(buf
->data
, cpu
)->skipped_entries
) {
2371 count
-= per_cpu_ptr(buf
->data
, cpu
)->skipped_entries
;
2372 /* total is the same as the entries */
2376 ring_buffer_overrun_cpu(buf
->buffer
, cpu
);
2381 static void print_lat_help_header(struct seq_file
*m
)
2383 seq_puts(m
, "# _------=> CPU# \n");
2384 seq_puts(m
, "# / _-----=> irqs-off \n");
2385 seq_puts(m
, "# | / _----=> need-resched \n");
2386 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
2387 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
2388 seq_puts(m
, "# |||| / delay \n");
2389 seq_puts(m
, "# cmd pid ||||| time | caller \n");
2390 seq_puts(m
, "# \\ / ||||| \\ | / \n");
2393 static void print_event_info(struct trace_buffer
*buf
, struct seq_file
*m
)
2395 unsigned long total
;
2396 unsigned long entries
;
2398 get_total_entries(buf
, &total
, &entries
);
2399 seq_printf(m
, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
2400 entries
, total
, num_online_cpus());
2404 static void print_func_help_header(struct trace_buffer
*buf
, struct seq_file
*m
)
2406 print_event_info(buf
, m
);
2407 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
2408 seq_puts(m
, "# | | | | |\n");
2411 static void print_func_help_header_irq(struct trace_buffer
*buf
, struct seq_file
*m
)
2413 print_event_info(buf
, m
);
2414 seq_puts(m
, "# _-----=> irqs-off\n");
2415 seq_puts(m
, "# / _----=> need-resched\n");
2416 seq_puts(m
, "# | / _---=> hardirq/softirq\n");
2417 seq_puts(m
, "# || / _--=> preempt-depth\n");
2418 seq_puts(m
, "# ||| / delay\n");
2419 seq_puts(m
, "# TASK-PID CPU# |||| TIMESTAMP FUNCTION\n");
2420 seq_puts(m
, "# | | | |||| | |\n");
2424 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
2426 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
2427 struct trace_buffer
*buf
= iter
->trace_buffer
;
2428 struct trace_array_cpu
*data
= per_cpu_ptr(buf
->data
, buf
->cpu
);
2429 struct tracer
*type
= iter
->trace
;
2430 unsigned long entries
;
2431 unsigned long total
;
2432 const char *name
= "preemption";
2436 get_total_entries(buf
, &total
, &entries
);
2438 seq_printf(m
, "# %s latency trace v1.1.5 on %s\n",
2440 seq_puts(m
, "# -----------------------------------"
2441 "---------------------------------\n");
2442 seq_printf(m
, "# latency: %lu us, #%lu/%lu, CPU#%d |"
2443 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
2444 nsecs_to_usecs(data
->saved_latency
),
2448 #if defined(CONFIG_PREEMPT_NONE)
2450 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
2452 #elif defined(CONFIG_PREEMPT)
2457 /* These are reserved for later use */
2460 seq_printf(m
, " #P:%d)\n", num_online_cpus());
2464 seq_puts(m
, "# -----------------\n");
2465 seq_printf(m
, "# | task: %.16s-%d "
2466 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
2467 data
->comm
, data
->pid
,
2468 from_kuid_munged(seq_user_ns(m
), data
->uid
), data
->nice
,
2469 data
->policy
, data
->rt_priority
);
2470 seq_puts(m
, "# -----------------\n");
2472 if (data
->critical_start
) {
2473 seq_puts(m
, "# => started at: ");
2474 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
2475 trace_print_seq(m
, &iter
->seq
);
2476 seq_puts(m
, "\n# => ended at: ");
2477 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
2478 trace_print_seq(m
, &iter
->seq
);
2479 seq_puts(m
, "\n#\n");
2485 static void test_cpu_buff_start(struct trace_iterator
*iter
)
2487 struct trace_seq
*s
= &iter
->seq
;
2489 if (!(trace_flags
& TRACE_ITER_ANNOTATE
))
2492 if (!(iter
->iter_flags
& TRACE_FILE_ANNOTATE
))
2495 if (cpumask_test_cpu(iter
->cpu
, iter
->started
))
2498 if (per_cpu_ptr(iter
->trace_buffer
->data
, iter
->cpu
)->skipped_entries
)
2501 cpumask_set_cpu(iter
->cpu
, iter
->started
);
2503 /* Don't print started cpu buffer for the first entry of the trace */
2505 trace_seq_printf(s
, "##### CPU %u buffer started ####\n",
2509 static enum print_line_t
print_trace_fmt(struct trace_iterator
*iter
)
2511 struct trace_seq
*s
= &iter
->seq
;
2512 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
2513 struct trace_entry
*entry
;
2514 struct trace_event
*event
;
2518 test_cpu_buff_start(iter
);
2520 event
= ftrace_find_event(entry
->type
);
2522 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2523 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
2524 if (!trace_print_lat_context(iter
))
2527 if (!trace_print_context(iter
))
2533 return event
->funcs
->trace(iter
, sym_flags
, event
);
2535 if (!trace_seq_printf(s
, "Unknown type %d\n", entry
->type
))
2538 return TRACE_TYPE_HANDLED
;
2540 return TRACE_TYPE_PARTIAL_LINE
;
2543 static enum print_line_t
print_raw_fmt(struct trace_iterator
*iter
)
2545 struct trace_seq
*s
= &iter
->seq
;
2546 struct trace_entry
*entry
;
2547 struct trace_event
*event
;
2551 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2552 if (!trace_seq_printf(s
, "%d %d %llu ",
2553 entry
->pid
, iter
->cpu
, iter
->ts
))
2557 event
= ftrace_find_event(entry
->type
);
2559 return event
->funcs
->raw(iter
, 0, event
);
2561 if (!trace_seq_printf(s
, "%d ?\n", entry
->type
))
2564 return TRACE_TYPE_HANDLED
;
2566 return TRACE_TYPE_PARTIAL_LINE
;
2569 static enum print_line_t
print_hex_fmt(struct trace_iterator
*iter
)
2571 struct trace_seq
*s
= &iter
->seq
;
2572 unsigned char newline
= '\n';
2573 struct trace_entry
*entry
;
2574 struct trace_event
*event
;
2578 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2579 SEQ_PUT_HEX_FIELD_RET(s
, entry
->pid
);
2580 SEQ_PUT_HEX_FIELD_RET(s
, iter
->cpu
);
2581 SEQ_PUT_HEX_FIELD_RET(s
, iter
->ts
);
2584 event
= ftrace_find_event(entry
->type
);
2586 enum print_line_t ret
= event
->funcs
->hex(iter
, 0, event
);
2587 if (ret
!= TRACE_TYPE_HANDLED
)
2591 SEQ_PUT_FIELD_RET(s
, newline
);
2593 return TRACE_TYPE_HANDLED
;
2596 static enum print_line_t
print_bin_fmt(struct trace_iterator
*iter
)
2598 struct trace_seq
*s
= &iter
->seq
;
2599 struct trace_entry
*entry
;
2600 struct trace_event
*event
;
2604 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2605 SEQ_PUT_FIELD_RET(s
, entry
->pid
);
2606 SEQ_PUT_FIELD_RET(s
, iter
->cpu
);
2607 SEQ_PUT_FIELD_RET(s
, iter
->ts
);
2610 event
= ftrace_find_event(entry
->type
);
2611 return event
? event
->funcs
->binary(iter
, 0, event
) :
2615 int trace_empty(struct trace_iterator
*iter
)
2617 struct ring_buffer_iter
*buf_iter
;
2620 /* If we are looking at one CPU buffer, only check that one */
2621 if (iter
->cpu_file
!= RING_BUFFER_ALL_CPUS
) {
2622 cpu
= iter
->cpu_file
;
2623 buf_iter
= trace_buffer_iter(iter
, cpu
);
2625 if (!ring_buffer_iter_empty(buf_iter
))
2628 if (!ring_buffer_empty_cpu(iter
->trace_buffer
->buffer
, cpu
))
2634 for_each_tracing_cpu(cpu
) {
2635 buf_iter
= trace_buffer_iter(iter
, cpu
);
2637 if (!ring_buffer_iter_empty(buf_iter
))
2640 if (!ring_buffer_empty_cpu(iter
->trace_buffer
->buffer
, cpu
))
2648 /* Called with trace_event_read_lock() held. */
2649 enum print_line_t
print_trace_line(struct trace_iterator
*iter
)
2651 enum print_line_t ret
;
2653 if (iter
->lost_events
&&
2654 !trace_seq_printf(&iter
->seq
, "CPU:%d [LOST %lu EVENTS]\n",
2655 iter
->cpu
, iter
->lost_events
))
2656 return TRACE_TYPE_PARTIAL_LINE
;
2658 if (iter
->trace
&& iter
->trace
->print_line
) {
2659 ret
= iter
->trace
->print_line(iter
);
2660 if (ret
!= TRACE_TYPE_UNHANDLED
)
2664 if (iter
->ent
->type
== TRACE_BPUTS
&&
2665 trace_flags
& TRACE_ITER_PRINTK
&&
2666 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2667 return trace_print_bputs_msg_only(iter
);
2669 if (iter
->ent
->type
== TRACE_BPRINT
&&
2670 trace_flags
& TRACE_ITER_PRINTK
&&
2671 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2672 return trace_print_bprintk_msg_only(iter
);
2674 if (iter
->ent
->type
== TRACE_PRINT
&&
2675 trace_flags
& TRACE_ITER_PRINTK
&&
2676 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2677 return trace_print_printk_msg_only(iter
);
2679 if (trace_flags
& TRACE_ITER_BIN
)
2680 return print_bin_fmt(iter
);
2682 if (trace_flags
& TRACE_ITER_HEX
)
2683 return print_hex_fmt(iter
);
2685 if (trace_flags
& TRACE_ITER_RAW
)
2686 return print_raw_fmt(iter
);
2688 return print_trace_fmt(iter
);
2691 void trace_latency_header(struct seq_file
*m
)
2693 struct trace_iterator
*iter
= m
->private;
2695 /* print nothing if the buffers are empty */
2696 if (trace_empty(iter
))
2699 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
)
2700 print_trace_header(m
, iter
);
2702 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2703 print_lat_help_header(m
);
2706 void trace_default_header(struct seq_file
*m
)
2708 struct trace_iterator
*iter
= m
->private;
2710 if (!(trace_flags
& TRACE_ITER_CONTEXT_INFO
))
2713 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
2714 /* print nothing if the buffers are empty */
2715 if (trace_empty(iter
))
2717 print_trace_header(m
, iter
);
2718 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2719 print_lat_help_header(m
);
2721 if (!(trace_flags
& TRACE_ITER_VERBOSE
)) {
2722 if (trace_flags
& TRACE_ITER_IRQ_INFO
)
2723 print_func_help_header_irq(iter
->trace_buffer
, m
);
2725 print_func_help_header(iter
->trace_buffer
, m
);
2730 static void test_ftrace_alive(struct seq_file
*m
)
2732 if (!ftrace_is_dead())
2734 seq_printf(m
, "# WARNING: FUNCTION TRACING IS CORRUPTED\n");
2735 seq_printf(m
, "# MAY BE MISSING FUNCTION EVENTS\n");
2738 #ifdef CONFIG_TRACER_MAX_TRACE
2739 static void show_snapshot_main_help(struct seq_file
*m
)
2741 seq_printf(m
, "# echo 0 > snapshot : Clears and frees snapshot buffer\n");
2742 seq_printf(m
, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
2743 seq_printf(m
, "# Takes a snapshot of the main buffer.\n");
2744 seq_printf(m
, "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate)\n");
2745 seq_printf(m
, "# (Doesn't have to be '2' works with any number that\n");
2746 seq_printf(m
, "# is not a '0' or '1')\n");
2749 static void show_snapshot_percpu_help(struct seq_file
*m
)
2751 seq_printf(m
, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
2752 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
2753 seq_printf(m
, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
2754 seq_printf(m
, "# Takes a snapshot of the main buffer for this cpu.\n");
2756 seq_printf(m
, "# echo 1 > snapshot : Not supported with this kernel.\n");
2757 seq_printf(m
, "# Must use main snapshot file to allocate.\n");
2759 seq_printf(m
, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n");
2760 seq_printf(m
, "# (Doesn't have to be '2' works with any number that\n");
2761 seq_printf(m
, "# is not a '0' or '1')\n");
2764 static void print_snapshot_help(struct seq_file
*m
, struct trace_iterator
*iter
)
2766 if (iter
->tr
->allocated_snapshot
)
2767 seq_printf(m
, "#\n# * Snapshot is allocated *\n#\n");
2769 seq_printf(m
, "#\n# * Snapshot is freed *\n#\n");
2771 seq_printf(m
, "# Snapshot commands:\n");
2772 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
)
2773 show_snapshot_main_help(m
);
2775 show_snapshot_percpu_help(m
);
2778 /* Should never be called */
2779 static inline void print_snapshot_help(struct seq_file
*m
, struct trace_iterator
*iter
) { }
2782 static int s_show(struct seq_file
*m
, void *v
)
2784 struct trace_iterator
*iter
= v
;
2787 if (iter
->ent
== NULL
) {
2789 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
2791 test_ftrace_alive(m
);
2793 if (iter
->snapshot
&& trace_empty(iter
))
2794 print_snapshot_help(m
, iter
);
2795 else if (iter
->trace
&& iter
->trace
->print_header
)
2796 iter
->trace
->print_header(m
);
2798 trace_default_header(m
);
2800 } else if (iter
->leftover
) {
2802 * If we filled the seq_file buffer earlier, we
2803 * want to just show it now.
2805 ret
= trace_print_seq(m
, &iter
->seq
);
2807 /* ret should this time be zero, but you never know */
2808 iter
->leftover
= ret
;
2811 print_trace_line(iter
);
2812 ret
= trace_print_seq(m
, &iter
->seq
);
2814 * If we overflow the seq_file buffer, then it will
2815 * ask us for this data again at start up.
2817 * ret is 0 if seq_file write succeeded.
2820 iter
->leftover
= ret
;
2826 static const struct seq_operations tracer_seq_ops
= {
2833 static struct trace_iterator
*
2834 __tracing_open(struct inode
*inode
, struct file
*file
, bool snapshot
)
2836 struct trace_cpu
*tc
= inode
->i_private
;
2837 struct trace_array
*tr
= tc
->tr
;
2838 struct trace_iterator
*iter
;
2841 if (tracing_disabled
)
2842 return ERR_PTR(-ENODEV
);
2844 iter
= __seq_open_private(file
, &tracer_seq_ops
, sizeof(*iter
));
2846 return ERR_PTR(-ENOMEM
);
2848 iter
->buffer_iter
= kzalloc(sizeof(*iter
->buffer_iter
) * num_possible_cpus(),
2850 if (!iter
->buffer_iter
)
2854 * We make a copy of the current tracer to avoid concurrent
2855 * changes on it while we are reading.
2857 mutex_lock(&trace_types_lock
);
2858 iter
->trace
= kzalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
2862 *iter
->trace
= *tr
->current_trace
;
2864 if (!zalloc_cpumask_var(&iter
->started
, GFP_KERNEL
))
2869 #ifdef CONFIG_TRACER_MAX_TRACE
2870 /* Currently only the top directory has a snapshot */
2871 if (tr
->current_trace
->print_max
|| snapshot
)
2872 iter
->trace_buffer
= &tr
->max_buffer
;
2875 iter
->trace_buffer
= &tr
->trace_buffer
;
2876 iter
->snapshot
= snapshot
;
2878 mutex_init(&iter
->mutex
);
2879 iter
->cpu_file
= tc
->cpu
;
2881 /* Notify the tracer early; before we stop tracing. */
2882 if (iter
->trace
&& iter
->trace
->open
)
2883 iter
->trace
->open(iter
);
2885 /* Annotate start of buffers if we had overruns */
2886 if (ring_buffer_overruns(iter
->trace_buffer
->buffer
))
2887 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
2889 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
2890 if (trace_clocks
[trace_clock_id
].in_ns
)
2891 iter
->iter_flags
|= TRACE_FILE_TIME_IN_NS
;
2893 /* stop the trace while dumping if we are not opening "snapshot" */
2894 if (!iter
->snapshot
)
2895 tracing_stop_tr(tr
);
2897 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
) {
2898 for_each_tracing_cpu(cpu
) {
2899 iter
->buffer_iter
[cpu
] =
2900 ring_buffer_read_prepare(iter
->trace_buffer
->buffer
, cpu
);
2902 ring_buffer_read_prepare_sync();
2903 for_each_tracing_cpu(cpu
) {
2904 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2905 tracing_iter_reset(iter
, cpu
);
2908 cpu
= iter
->cpu_file
;
2909 iter
->buffer_iter
[cpu
] =
2910 ring_buffer_read_prepare(iter
->trace_buffer
->buffer
, cpu
);
2911 ring_buffer_read_prepare_sync();
2912 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2913 tracing_iter_reset(iter
, cpu
);
2918 mutex_unlock(&trace_types_lock
);
2923 mutex_unlock(&trace_types_lock
);
2925 kfree(iter
->buffer_iter
);
2927 seq_release_private(inode
, file
);
2928 return ERR_PTR(-ENOMEM
);
2931 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
2933 if (tracing_disabled
)
2936 filp
->private_data
= inode
->i_private
;
2940 static int tracing_release(struct inode
*inode
, struct file
*file
)
2942 struct seq_file
*m
= file
->private_data
;
2943 struct trace_iterator
*iter
;
2944 struct trace_array
*tr
;
2947 if (!(file
->f_mode
& FMODE_READ
))
2953 mutex_lock(&trace_types_lock
);
2958 for_each_tracing_cpu(cpu
) {
2959 if (iter
->buffer_iter
[cpu
])
2960 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
2963 if (iter
->trace
&& iter
->trace
->close
)
2964 iter
->trace
->close(iter
);
2966 if (!iter
->snapshot
)
2967 /* reenable tracing if it was previously enabled */
2968 tracing_start_tr(tr
);
2969 mutex_unlock(&trace_types_lock
);
2971 mutex_destroy(&iter
->mutex
);
2972 free_cpumask_var(iter
->started
);
2974 kfree(iter
->buffer_iter
);
2975 seq_release_private(inode
, file
);
2979 static int tracing_open(struct inode
*inode
, struct file
*file
)
2981 struct trace_iterator
*iter
;
2984 /* If this file was open for write, then erase contents */
2985 if ((file
->f_mode
& FMODE_WRITE
) &&
2986 (file
->f_flags
& O_TRUNC
)) {
2987 struct trace_cpu
*tc
= inode
->i_private
;
2988 struct trace_array
*tr
= tc
->tr
;
2990 if (tc
->cpu
== RING_BUFFER_ALL_CPUS
)
2991 tracing_reset_online_cpus(&tr
->trace_buffer
);
2993 tracing_reset(&tr
->trace_buffer
, tc
->cpu
);
2996 if (file
->f_mode
& FMODE_READ
) {
2997 iter
= __tracing_open(inode
, file
, false);
2999 ret
= PTR_ERR(iter
);
3000 else if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
3001 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
3007 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
3009 struct tracer
*t
= v
;
3019 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
3024 mutex_lock(&trace_types_lock
);
3025 for (t
= trace_types
; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
3031 static void t_stop(struct seq_file
*m
, void *p
)
3033 mutex_unlock(&trace_types_lock
);
3036 static int t_show(struct seq_file
*m
, void *v
)
3038 struct tracer
*t
= v
;
3043 seq_printf(m
, "%s", t
->name
);
3052 static const struct seq_operations show_traces_seq_ops
= {
3059 static int show_traces_open(struct inode
*inode
, struct file
*file
)
3061 if (tracing_disabled
)
3064 return seq_open(file
, &show_traces_seq_ops
);
3068 tracing_write_stub(struct file
*filp
, const char __user
*ubuf
,
3069 size_t count
, loff_t
*ppos
)
3074 static loff_t
tracing_seek(struct file
*file
, loff_t offset
, int origin
)
3076 if (file
->f_mode
& FMODE_READ
)
3077 return seq_lseek(file
, offset
, origin
);
3082 static const struct file_operations tracing_fops
= {
3083 .open
= tracing_open
,
3085 .write
= tracing_write_stub
,
3086 .llseek
= tracing_seek
,
3087 .release
= tracing_release
,
3090 static const struct file_operations show_traces_fops
= {
3091 .open
= show_traces_open
,
3093 .release
= seq_release
,
3094 .llseek
= seq_lseek
,
3098 * Only trace on a CPU if the bitmask is set:
3100 static cpumask_var_t tracing_cpumask
;
3103 * The tracer itself will not take this lock, but still we want
3104 * to provide a consistent cpumask to user-space:
3106 static DEFINE_MUTEX(tracing_cpumask_update_lock
);
3109 * Temporary storage for the character representation of the
3110 * CPU bitmask (and one more byte for the newline):
3112 static char mask_str
[NR_CPUS
+ 1];
3115 tracing_cpumask_read(struct file
*filp
, char __user
*ubuf
,
3116 size_t count
, loff_t
*ppos
)
3120 mutex_lock(&tracing_cpumask_update_lock
);
3122 len
= cpumask_scnprintf(mask_str
, count
, tracing_cpumask
);
3123 if (count
- len
< 2) {
3127 len
+= sprintf(mask_str
+ len
, "\n");
3128 count
= simple_read_from_buffer(ubuf
, count
, ppos
, mask_str
, NR_CPUS
+1);
3131 mutex_unlock(&tracing_cpumask_update_lock
);
3137 tracing_cpumask_write(struct file
*filp
, const char __user
*ubuf
,
3138 size_t count
, loff_t
*ppos
)
3140 struct trace_array
*tr
= filp
->private_data
;
3141 cpumask_var_t tracing_cpumask_new
;
3144 if (!alloc_cpumask_var(&tracing_cpumask_new
, GFP_KERNEL
))
3147 err
= cpumask_parse_user(ubuf
, count
, tracing_cpumask_new
);
3151 mutex_lock(&tracing_cpumask_update_lock
);
3153 local_irq_disable();
3154 arch_spin_lock(&ftrace_max_lock
);
3155 for_each_tracing_cpu(cpu
) {
3157 * Increase/decrease the disabled counter if we are
3158 * about to flip a bit in the cpumask:
3160 if (cpumask_test_cpu(cpu
, tracing_cpumask
) &&
3161 !cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
3162 atomic_inc(&per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->disabled
);
3163 ring_buffer_record_disable_cpu(tr
->trace_buffer
.buffer
, cpu
);
3165 if (!cpumask_test_cpu(cpu
, tracing_cpumask
) &&
3166 cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
3167 atomic_dec(&per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->disabled
);
3168 ring_buffer_record_enable_cpu(tr
->trace_buffer
.buffer
, cpu
);
3171 arch_spin_unlock(&ftrace_max_lock
);
3174 cpumask_copy(tracing_cpumask
, tracing_cpumask_new
);
3176 mutex_unlock(&tracing_cpumask_update_lock
);
3177 free_cpumask_var(tracing_cpumask_new
);
3182 free_cpumask_var(tracing_cpumask_new
);
3187 static const struct file_operations tracing_cpumask_fops
= {
3188 .open
= tracing_open_generic
,
3189 .read
= tracing_cpumask_read
,
3190 .write
= tracing_cpumask_write
,
3191 .llseek
= generic_file_llseek
,
3194 static int tracing_trace_options_show(struct seq_file
*m
, void *v
)
3196 struct tracer_opt
*trace_opts
;
3197 struct trace_array
*tr
= m
->private;
3201 mutex_lock(&trace_types_lock
);
3202 tracer_flags
= tr
->current_trace
->flags
->val
;
3203 trace_opts
= tr
->current_trace
->flags
->opts
;
3205 for (i
= 0; trace_options
[i
]; i
++) {
3206 if (trace_flags
& (1 << i
))
3207 seq_printf(m
, "%s\n", trace_options
[i
]);
3209 seq_printf(m
, "no%s\n", trace_options
[i
]);
3212 for (i
= 0; trace_opts
[i
].name
; i
++) {
3213 if (tracer_flags
& trace_opts
[i
].bit
)
3214 seq_printf(m
, "%s\n", trace_opts
[i
].name
);
3216 seq_printf(m
, "no%s\n", trace_opts
[i
].name
);
3218 mutex_unlock(&trace_types_lock
);
3223 static int __set_tracer_option(struct tracer
*trace
,
3224 struct tracer_flags
*tracer_flags
,
3225 struct tracer_opt
*opts
, int neg
)
3229 ret
= trace
->set_flag(tracer_flags
->val
, opts
->bit
, !neg
);
3234 tracer_flags
->val
&= ~opts
->bit
;
3236 tracer_flags
->val
|= opts
->bit
;
3240 /* Try to assign a tracer specific option */
3241 static int set_tracer_option(struct tracer
*trace
, char *cmp
, int neg
)
3243 struct tracer_flags
*tracer_flags
= trace
->flags
;
3244 struct tracer_opt
*opts
= NULL
;
3247 for (i
= 0; tracer_flags
->opts
[i
].name
; i
++) {
3248 opts
= &tracer_flags
->opts
[i
];
3250 if (strcmp(cmp
, opts
->name
) == 0)
3251 return __set_tracer_option(trace
, trace
->flags
,
3258 /* Some tracers require overwrite to stay enabled */
3259 int trace_keep_overwrite(struct tracer
*tracer
, u32 mask
, int set
)
3261 if (tracer
->enabled
&& (mask
& TRACE_ITER_OVERWRITE
) && !set
)
3267 int set_tracer_flag(struct trace_array
*tr
, unsigned int mask
, int enabled
)
3269 /* do nothing if flag is already set */
3270 if (!!(trace_flags
& mask
) == !!enabled
)
3273 /* Give the tracer a chance to approve the change */
3274 if (tr
->current_trace
->flag_changed
)
3275 if (tr
->current_trace
->flag_changed(tr
->current_trace
, mask
, !!enabled
))
3279 trace_flags
|= mask
;
3281 trace_flags
&= ~mask
;
3283 if (mask
== TRACE_ITER_RECORD_CMD
)
3284 trace_event_enable_cmd_record(enabled
);
3286 if (mask
== TRACE_ITER_OVERWRITE
) {
3287 ring_buffer_change_overwrite(tr
->trace_buffer
.buffer
, enabled
);
3288 #ifdef CONFIG_TRACER_MAX_TRACE
3289 ring_buffer_change_overwrite(tr
->max_buffer
.buffer
, enabled
);
3293 if (mask
== TRACE_ITER_PRINTK
)
3294 trace_printk_start_stop_comm(enabled
);
3299 static int trace_set_options(struct trace_array
*tr
, char *option
)
3306 cmp
= strstrip(option
);
3308 if (strncmp(cmp
, "no", 2) == 0) {
3313 mutex_lock(&trace_types_lock
);
3315 for (i
= 0; trace_options
[i
]; i
++) {
3316 if (strcmp(cmp
, trace_options
[i
]) == 0) {
3317 ret
= set_tracer_flag(tr
, 1 << i
, !neg
);
3322 /* If no option could be set, test the specific tracer options */
3323 if (!trace_options
[i
])
3324 ret
= set_tracer_option(tr
->current_trace
, cmp
, neg
);
3326 mutex_unlock(&trace_types_lock
);
3332 tracing_trace_options_write(struct file
*filp
, const char __user
*ubuf
,
3333 size_t cnt
, loff_t
*ppos
)
3335 struct seq_file
*m
= filp
->private_data
;
3336 struct trace_array
*tr
= m
->private;
3340 if (cnt
>= sizeof(buf
))
3343 if (copy_from_user(&buf
, ubuf
, cnt
))
3348 ret
= trace_set_options(tr
, buf
);
3357 static int tracing_trace_options_open(struct inode
*inode
, struct file
*file
)
3359 if (tracing_disabled
)
3362 return single_open(file
, tracing_trace_options_show
, inode
->i_private
);
3365 static const struct file_operations tracing_iter_fops
= {
3366 .open
= tracing_trace_options_open
,
3368 .llseek
= seq_lseek
,
3369 .release
= single_release
,
3370 .write
= tracing_trace_options_write
,
3373 static const char readme_msg
[] =
3374 "tracing mini-HOWTO:\n\n"
3375 "# echo 0 > tracing_on : quick way to disable tracing\n"
3376 "# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
3377 " Important files:\n"
3378 " trace\t\t\t- The static contents of the buffer\n"
3379 "\t\t\t To clear the buffer write into this file: echo > trace\n"
3380 " trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
3381 " current_tracer\t- function and latency tracers\n"
3382 " available_tracers\t- list of configured tracers for current_tracer\n"
3383 " buffer_size_kb\t- view and modify size of per cpu buffer\n"
3384 " buffer_total_size_kb - view total size of all cpu buffers\n\n"
3385 " trace_clock\t\t-change the clock used to order events\n"
3386 " local: Per cpu clock but may not be synced across CPUs\n"
3387 " global: Synced across CPUs but slows tracing down.\n"
3388 " counter: Not a clock, but just an increment\n"
3389 " uptime: Jiffy counter from time of boot\n"
3390 " perf: Same clock that perf events use\n"
3391 #ifdef CONFIG_X86_64
3392 " x86-tsc: TSC cycle counter\n"
3394 "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
3395 " tracing_cpumask\t- Limit which CPUs to trace\n"
3396 " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
3397 "\t\t\t Remove sub-buffer with rmdir\n"
3398 " trace_options\t\t- Set format or modify how tracing happens\n"
3399 "\t\t\t Disable an option by adding a suffix 'no' to the option name\n"
3400 #ifdef CONFIG_DYNAMIC_FTRACE
3401 "\n available_filter_functions - list of functions that can be filtered on\n"
3402 " set_ftrace_filter\t- echo function name in here to only trace these functions\n"
3403 " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3404 " modules: Can select a group via module\n"
3405 " Format: :mod:<module-name>\n"
3406 " example: echo :mod:ext3 > set_ftrace_filter\n"
3407 " triggers: a command to perform when function is hit\n"
3408 " Format: <function>:<trigger>[:count]\n"
3409 " trigger: traceon, traceoff\n"
3410 " enable_event:<system>:<event>\n"
3411 " disable_event:<system>:<event>\n"
3412 #ifdef CONFIG_STACKTRACE
3415 #ifdef CONFIG_TRACER_SNAPSHOT
3418 " example: echo do_fault:traceoff > set_ftrace_filter\n"
3419 " echo do_trap:traceoff:3 > set_ftrace_filter\n"
3420 " The first one will disable tracing every time do_fault is hit\n"
3421 " The second will disable tracing at most 3 times when do_trap is hit\n"
3422 " The first time do trap is hit and it disables tracing, the counter\n"
3423 " will decrement to 2. If tracing is already disabled, the counter\n"
3424 " will not decrement. It only decrements when the trigger did work\n"
3425 " To remove trigger without count:\n"
3426 " echo '!<function>:<trigger> > set_ftrace_filter\n"
3427 " To remove trigger with a count:\n"
3428 " echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
3429 " set_ftrace_notrace\t- echo function name in here to never trace.\n"
3430 " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3431 " modules: Can select a group via module command :mod:\n"
3432 " Does not accept triggers\n"
3433 #endif /* CONFIG_DYNAMIC_FTRACE */
3434 #ifdef CONFIG_FUNCTION_TRACER
3435 " set_ftrace_pid\t- Write pid(s) to only function trace those pids (function)\n"
3437 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3438 " set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
3439 " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
3441 #ifdef CONFIG_TRACER_SNAPSHOT
3442 "\n snapshot\t\t- Like 'trace' but shows the content of the static snapshot buffer\n"
3443 "\t\t\t Read the contents for more information\n"
3445 #ifdef CONFIG_STACKTRACE
3446 " stack_trace\t\t- Shows the max stack trace when active\n"
3447 " stack_max_size\t- Shows current max stack size that was traced\n"
3448 "\t\t\t Write into this file to reset the max size (trigger a new trace)\n"
3449 #ifdef CONFIG_DYNAMIC_FTRACE
3450 " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace traces\n"
3452 #endif /* CONFIG_STACKTRACE */
3456 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
3457 size_t cnt
, loff_t
*ppos
)
3459 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
3460 readme_msg
, strlen(readme_msg
));
3463 static const struct file_operations tracing_readme_fops
= {
3464 .open
= tracing_open_generic
,
3465 .read
= tracing_readme_read
,
3466 .llseek
= generic_file_llseek
,
3470 tracing_saved_cmdlines_read(struct file
*file
, char __user
*ubuf
,
3471 size_t cnt
, loff_t
*ppos
)
3480 file_buf
= kmalloc(SAVED_CMDLINES
*(16+TASK_COMM_LEN
), GFP_KERNEL
);
3484 buf_comm
= kmalloc(TASK_COMM_LEN
, GFP_KERNEL
);
3492 for (i
= 0; i
< SAVED_CMDLINES
; i
++) {
3495 pid
= map_cmdline_to_pid
[i
];
3496 if (pid
== -1 || pid
== NO_CMDLINE_MAP
)
3499 trace_find_cmdline(pid
, buf_comm
);
3500 r
= sprintf(buf
, "%d %s\n", pid
, buf_comm
);
3505 len
= simple_read_from_buffer(ubuf
, cnt
, ppos
,
3514 static const struct file_operations tracing_saved_cmdlines_fops
= {
3515 .open
= tracing_open_generic
,
3516 .read
= tracing_saved_cmdlines_read
,
3517 .llseek
= generic_file_llseek
,
3521 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
3522 size_t cnt
, loff_t
*ppos
)
3524 struct trace_array
*tr
= filp
->private_data
;
3525 char buf
[MAX_TRACER_SIZE
+2];
3528 mutex_lock(&trace_types_lock
);
3529 r
= sprintf(buf
, "%s\n", tr
->current_trace
->name
);
3530 mutex_unlock(&trace_types_lock
);
3532 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3535 int tracer_init(struct tracer
*t
, struct trace_array
*tr
)
3537 tracing_reset_online_cpus(&tr
->trace_buffer
);
3541 static void set_buffer_entries(struct trace_buffer
*buf
, unsigned long val
)
3545 for_each_tracing_cpu(cpu
)
3546 per_cpu_ptr(buf
->data
, cpu
)->entries
= val
;
3549 #ifdef CONFIG_TRACER_MAX_TRACE
3550 /* resize @tr's buffer to the size of @size_tr's entries */
3551 static int resize_buffer_duplicate_size(struct trace_buffer
*trace_buf
,
3552 struct trace_buffer
*size_buf
, int cpu_id
)
3556 if (cpu_id
== RING_BUFFER_ALL_CPUS
) {
3557 for_each_tracing_cpu(cpu
) {
3558 ret
= ring_buffer_resize(trace_buf
->buffer
,
3559 per_cpu_ptr(size_buf
->data
, cpu
)->entries
, cpu
);
3562 per_cpu_ptr(trace_buf
->data
, cpu
)->entries
=
3563 per_cpu_ptr(size_buf
->data
, cpu
)->entries
;
3566 ret
= ring_buffer_resize(trace_buf
->buffer
,
3567 per_cpu_ptr(size_buf
->data
, cpu_id
)->entries
, cpu_id
);
3569 per_cpu_ptr(trace_buf
->data
, cpu_id
)->entries
=
3570 per_cpu_ptr(size_buf
->data
, cpu_id
)->entries
;
3575 #endif /* CONFIG_TRACER_MAX_TRACE */
3577 static int __tracing_resize_ring_buffer(struct trace_array
*tr
,
3578 unsigned long size
, int cpu
)
3583 * If kernel or user changes the size of the ring buffer
3584 * we use the size that was given, and we can forget about
3585 * expanding it later.
3587 ring_buffer_expanded
= true;
3589 /* May be called before buffers are initialized */
3590 if (!tr
->trace_buffer
.buffer
)
3593 ret
= ring_buffer_resize(tr
->trace_buffer
.buffer
, size
, cpu
);
3597 #ifdef CONFIG_TRACER_MAX_TRACE
3598 if (!(tr
->flags
& TRACE_ARRAY_FL_GLOBAL
) ||
3599 !tr
->current_trace
->use_max_tr
)
3602 ret
= ring_buffer_resize(tr
->max_buffer
.buffer
, size
, cpu
);
3604 int r
= resize_buffer_duplicate_size(&tr
->trace_buffer
,
3605 &tr
->trace_buffer
, cpu
);
3608 * AARGH! We are left with different
3609 * size max buffer!!!!
3610 * The max buffer is our "snapshot" buffer.
3611 * When a tracer needs a snapshot (one of the
3612 * latency tracers), it swaps the max buffer
3613 * with the saved snap shot. We succeeded to
3614 * update the size of the main buffer, but failed to
3615 * update the size of the max buffer. But when we tried
3616 * to reset the main buffer to the original size, we
3617 * failed there too. This is very unlikely to
3618 * happen, but if it does, warn and kill all
3622 tracing_disabled
= 1;
3627 if (cpu
== RING_BUFFER_ALL_CPUS
)
3628 set_buffer_entries(&tr
->max_buffer
, size
);
3630 per_cpu_ptr(tr
->max_buffer
.data
, cpu
)->entries
= size
;
3633 #endif /* CONFIG_TRACER_MAX_TRACE */
3635 if (cpu
== RING_BUFFER_ALL_CPUS
)
3636 set_buffer_entries(&tr
->trace_buffer
, size
);
3638 per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
= size
;
3643 static ssize_t
tracing_resize_ring_buffer(struct trace_array
*tr
,
3644 unsigned long size
, int cpu_id
)
3648 mutex_lock(&trace_types_lock
);
3650 if (cpu_id
!= RING_BUFFER_ALL_CPUS
) {
3651 /* make sure, this cpu is enabled in the mask */
3652 if (!cpumask_test_cpu(cpu_id
, tracing_buffer_mask
)) {
3658 ret
= __tracing_resize_ring_buffer(tr
, size
, cpu_id
);
3663 mutex_unlock(&trace_types_lock
);
3670 * tracing_update_buffers - used by tracing facility to expand ring buffers
3672 * To save on memory when the tracing is never used on a system with it
3673 * configured in. The ring buffers are set to a minimum size. But once
3674 * a user starts to use the tracing facility, then they need to grow
3675 * to their default size.
3677 * This function is to be called when a tracer is about to be used.
3679 int tracing_update_buffers(void)
3683 mutex_lock(&trace_types_lock
);
3684 if (!ring_buffer_expanded
)
3685 ret
= __tracing_resize_ring_buffer(&global_trace
, trace_buf_size
,
3686 RING_BUFFER_ALL_CPUS
);
3687 mutex_unlock(&trace_types_lock
);
3692 struct trace_option_dentry
;
3694 static struct trace_option_dentry
*
3695 create_trace_option_files(struct trace_array
*tr
, struct tracer
*tracer
);
3698 destroy_trace_option_files(struct trace_option_dentry
*topts
);
3700 static int tracing_set_tracer(const char *buf
)
3702 static struct trace_option_dentry
*topts
;
3703 struct trace_array
*tr
= &global_trace
;
3705 #ifdef CONFIG_TRACER_MAX_TRACE
3710 mutex_lock(&trace_types_lock
);
3712 if (!ring_buffer_expanded
) {
3713 ret
= __tracing_resize_ring_buffer(tr
, trace_buf_size
,
3714 RING_BUFFER_ALL_CPUS
);
3720 for (t
= trace_types
; t
; t
= t
->next
) {
3721 if (strcmp(t
->name
, buf
) == 0)
3728 if (t
== tr
->current_trace
)
3731 trace_branch_disable();
3733 tr
->current_trace
->enabled
= false;
3735 if (tr
->current_trace
->reset
)
3736 tr
->current_trace
->reset(tr
);
3738 /* Current trace needs to be nop_trace before synchronize_sched */
3739 tr
->current_trace
= &nop_trace
;
3741 #ifdef CONFIG_TRACER_MAX_TRACE
3742 had_max_tr
= tr
->allocated_snapshot
;
3744 if (had_max_tr
&& !t
->use_max_tr
) {
3746 * We need to make sure that the update_max_tr sees that
3747 * current_trace changed to nop_trace to keep it from
3748 * swapping the buffers after we resize it.
3749 * The update_max_tr is called from interrupts disabled
3750 * so a synchronized_sched() is sufficient.
3752 synchronize_sched();
3756 destroy_trace_option_files(topts
);
3758 topts
= create_trace_option_files(tr
, t
);
3760 #ifdef CONFIG_TRACER_MAX_TRACE
3761 if (t
->use_max_tr
&& !had_max_tr
) {
3762 ret
= alloc_snapshot(tr
);
3769 ret
= tracer_init(t
, tr
);
3774 tr
->current_trace
= t
;
3775 tr
->current_trace
->enabled
= true;
3776 trace_branch_enable(tr
);
3778 mutex_unlock(&trace_types_lock
);
3784 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
3785 size_t cnt
, loff_t
*ppos
)
3787 char buf
[MAX_TRACER_SIZE
+1];
3794 if (cnt
> MAX_TRACER_SIZE
)
3795 cnt
= MAX_TRACER_SIZE
;
3797 if (copy_from_user(&buf
, ubuf
, cnt
))
3802 /* strip ending whitespace. */
3803 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
3806 err
= tracing_set_tracer(buf
);
3816 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
3817 size_t cnt
, loff_t
*ppos
)
3819 unsigned long *ptr
= filp
->private_data
;
3823 r
= snprintf(buf
, sizeof(buf
), "%ld\n",
3824 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
3825 if (r
> sizeof(buf
))
3827 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3831 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
3832 size_t cnt
, loff_t
*ppos
)
3834 unsigned long *ptr
= filp
->private_data
;
3838 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
3847 static int tracing_open_pipe(struct inode
*inode
, struct file
*filp
)
3849 struct trace_cpu
*tc
= inode
->i_private
;
3850 struct trace_array
*tr
= tc
->tr
;
3851 struct trace_iterator
*iter
;
3854 if (tracing_disabled
)
3857 mutex_lock(&trace_types_lock
);
3859 /* create a buffer to store the information to pass to userspace */
3860 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
3867 * We make a copy of the current tracer to avoid concurrent
3868 * changes on it while we are reading.
3870 iter
->trace
= kmalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
3875 *iter
->trace
= *tr
->current_trace
;
3877 if (!alloc_cpumask_var(&iter
->started
, GFP_KERNEL
)) {
3882 /* trace pipe does not show start of buffer */
3883 cpumask_setall(iter
->started
);
3885 if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
3886 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
3888 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
3889 if (trace_clocks
[trace_clock_id
].in_ns
)
3890 iter
->iter_flags
|= TRACE_FILE_TIME_IN_NS
;
3892 iter
->cpu_file
= tc
->cpu
;
3894 iter
->trace_buffer
= &tc
->tr
->trace_buffer
;
3895 mutex_init(&iter
->mutex
);
3896 filp
->private_data
= iter
;
3898 if (iter
->trace
->pipe_open
)
3899 iter
->trace
->pipe_open(iter
);
3901 nonseekable_open(inode
, filp
);
3903 mutex_unlock(&trace_types_lock
);
3909 mutex_unlock(&trace_types_lock
);
3913 static int tracing_release_pipe(struct inode
*inode
, struct file
*file
)
3915 struct trace_iterator
*iter
= file
->private_data
;
3917 mutex_lock(&trace_types_lock
);
3919 if (iter
->trace
->pipe_close
)
3920 iter
->trace
->pipe_close(iter
);
3922 mutex_unlock(&trace_types_lock
);
3924 free_cpumask_var(iter
->started
);
3925 mutex_destroy(&iter
->mutex
);
3933 trace_poll(struct trace_iterator
*iter
, struct file
*filp
, poll_table
*poll_table
)
3935 /* Iterators are static, they should be filled or empty */
3936 if (trace_buffer_iter(iter
, iter
->cpu_file
))
3937 return POLLIN
| POLLRDNORM
;
3939 if (trace_flags
& TRACE_ITER_BLOCK
)
3941 * Always select as readable when in blocking mode
3943 return POLLIN
| POLLRDNORM
;
3945 return ring_buffer_poll_wait(iter
->trace_buffer
->buffer
, iter
->cpu_file
,
3950 tracing_poll_pipe(struct file
*filp
, poll_table
*poll_table
)
3952 struct trace_iterator
*iter
= filp
->private_data
;
3954 return trace_poll(iter
, filp
, poll_table
);
3958 * This is a make-shift waitqueue.
3959 * A tracer might use this callback on some rare cases:
3961 * 1) the current tracer might hold the runqueue lock when it wakes up
3962 * a reader, hence a deadlock (sched, function, and function graph tracers)
3963 * 2) the function tracers, trace all functions, we don't want
3964 * the overhead of calling wake_up and friends
3965 * (and tracing them too)
3967 * Anyway, this is really very primitive wakeup.
3969 void poll_wait_pipe(struct trace_iterator
*iter
)
3971 set_current_state(TASK_INTERRUPTIBLE
);
3972 /* sleep for 100 msecs, and try again. */
3973 schedule_timeout(HZ
/ 10);
3976 /* Must be called with trace_types_lock mutex held. */
3977 static int tracing_wait_pipe(struct file
*filp
)
3979 struct trace_iterator
*iter
= filp
->private_data
;
3981 while (trace_empty(iter
)) {
3983 if ((filp
->f_flags
& O_NONBLOCK
)) {
3987 mutex_unlock(&iter
->mutex
);
3989 iter
->trace
->wait_pipe(iter
);
3991 mutex_lock(&iter
->mutex
);
3993 if (signal_pending(current
))
3997 * We block until we read something and tracing is disabled.
3998 * We still block if tracing is disabled, but we have never
3999 * read anything. This allows a user to cat this file, and
4000 * then enable tracing. But after we have read something,
4001 * we give an EOF when tracing is again disabled.
4003 * iter->pos will be 0 if we haven't read anything.
4005 if (!tracing_is_on() && iter
->pos
)
4016 tracing_read_pipe(struct file
*filp
, char __user
*ubuf
,
4017 size_t cnt
, loff_t
*ppos
)
4019 struct trace_iterator
*iter
= filp
->private_data
;
4020 struct trace_array
*tr
= iter
->tr
;
4023 /* return any leftover data */
4024 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
4028 trace_seq_init(&iter
->seq
);
4030 /* copy the tracer to avoid using a global lock all around */
4031 mutex_lock(&trace_types_lock
);
4032 if (unlikely(iter
->trace
->name
!= tr
->current_trace
->name
))
4033 *iter
->trace
= *tr
->current_trace
;
4034 mutex_unlock(&trace_types_lock
);
4037 * Avoid more than one consumer on a single file descriptor
4038 * This is just a matter of traces coherency, the ring buffer itself
4041 mutex_lock(&iter
->mutex
);
4042 if (iter
->trace
->read
) {
4043 sret
= iter
->trace
->read(iter
, filp
, ubuf
, cnt
, ppos
);
4049 sret
= tracing_wait_pipe(filp
);
4053 /* stop when tracing is finished */
4054 if (trace_empty(iter
)) {
4059 if (cnt
>= PAGE_SIZE
)
4060 cnt
= PAGE_SIZE
- 1;
4062 /* reset all but tr, trace, and overruns */
4063 memset(&iter
->seq
, 0,
4064 sizeof(struct trace_iterator
) -
4065 offsetof(struct trace_iterator
, seq
));
4068 trace_event_read_lock();
4069 trace_access_lock(iter
->cpu_file
);
4070 while (trace_find_next_entry_inc(iter
) != NULL
) {
4071 enum print_line_t ret
;
4072 int len
= iter
->seq
.len
;
4074 ret
= print_trace_line(iter
);
4075 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
4076 /* don't print partial lines */
4077 iter
->seq
.len
= len
;
4080 if (ret
!= TRACE_TYPE_NO_CONSUME
)
4081 trace_consume(iter
);
4083 if (iter
->seq
.len
>= cnt
)
4087 * Setting the full flag means we reached the trace_seq buffer
4088 * size and we should leave by partial output condition above.
4089 * One of the trace_seq_* functions is not used properly.
4091 WARN_ONCE(iter
->seq
.full
, "full flag set for trace type %d",
4094 trace_access_unlock(iter
->cpu_file
);
4095 trace_event_read_unlock();
4097 /* Now copy what we have to the user */
4098 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
4099 if (iter
->seq
.readpos
>= iter
->seq
.len
)
4100 trace_seq_init(&iter
->seq
);
4103 * If there was nothing to send to user, in spite of consuming trace
4104 * entries, go back to wait for more entries.
4110 mutex_unlock(&iter
->mutex
);
4115 static void tracing_pipe_buf_release(struct pipe_inode_info
*pipe
,
4116 struct pipe_buffer
*buf
)
4118 __free_page(buf
->page
);
4121 static void tracing_spd_release_pipe(struct splice_pipe_desc
*spd
,
4124 __free_page(spd
->pages
[idx
]);
4127 static const struct pipe_buf_operations tracing_pipe_buf_ops
= {
4129 .map
= generic_pipe_buf_map
,
4130 .unmap
= generic_pipe_buf_unmap
,
4131 .confirm
= generic_pipe_buf_confirm
,
4132 .release
= tracing_pipe_buf_release
,
4133 .steal
= generic_pipe_buf_steal
,
4134 .get
= generic_pipe_buf_get
,
4138 tracing_fill_pipe_page(size_t rem
, struct trace_iterator
*iter
)
4143 /* Seq buffer is page-sized, exactly what we need. */
4145 count
= iter
->seq
.len
;
4146 ret
= print_trace_line(iter
);
4147 count
= iter
->seq
.len
- count
;
4150 iter
->seq
.len
-= count
;
4153 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
4154 iter
->seq
.len
-= count
;
4158 if (ret
!= TRACE_TYPE_NO_CONSUME
)
4159 trace_consume(iter
);
4161 if (!trace_find_next_entry_inc(iter
)) {
4171 static ssize_t
tracing_splice_read_pipe(struct file
*filp
,
4173 struct pipe_inode_info
*pipe
,
4177 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
4178 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
4179 struct trace_iterator
*iter
= filp
->private_data
;
4180 struct splice_pipe_desc spd
= {
4182 .partial
= partial_def
,
4183 .nr_pages
= 0, /* This gets updated below. */
4184 .nr_pages_max
= PIPE_DEF_BUFFERS
,
4186 .ops
= &tracing_pipe_buf_ops
,
4187 .spd_release
= tracing_spd_release_pipe
,
4189 struct trace_array
*tr
= iter
->tr
;
4194 if (splice_grow_spd(pipe
, &spd
))
4197 /* copy the tracer to avoid using a global lock all around */
4198 mutex_lock(&trace_types_lock
);
4199 if (unlikely(iter
->trace
->name
!= tr
->current_trace
->name
))
4200 *iter
->trace
= *tr
->current_trace
;
4201 mutex_unlock(&trace_types_lock
);
4203 mutex_lock(&iter
->mutex
);
4205 if (iter
->trace
->splice_read
) {
4206 ret
= iter
->trace
->splice_read(iter
, filp
,
4207 ppos
, pipe
, len
, flags
);
4212 ret
= tracing_wait_pipe(filp
);
4216 if (!iter
->ent
&& !trace_find_next_entry_inc(iter
)) {
4221 trace_event_read_lock();
4222 trace_access_lock(iter
->cpu_file
);
4224 /* Fill as many pages as possible. */
4225 for (i
= 0, rem
= len
; i
< pipe
->buffers
&& rem
; i
++) {
4226 spd
.pages
[i
] = alloc_page(GFP_KERNEL
);
4230 rem
= tracing_fill_pipe_page(rem
, iter
);
4232 /* Copy the data into the page, so we can start over. */
4233 ret
= trace_seq_to_buffer(&iter
->seq
,
4234 page_address(spd
.pages
[i
]),
4237 __free_page(spd
.pages
[i
]);
4240 spd
.partial
[i
].offset
= 0;
4241 spd
.partial
[i
].len
= iter
->seq
.len
;
4243 trace_seq_init(&iter
->seq
);
4246 trace_access_unlock(iter
->cpu_file
);
4247 trace_event_read_unlock();
4248 mutex_unlock(&iter
->mutex
);
4252 ret
= splice_to_pipe(pipe
, &spd
);
4254 splice_shrink_spd(&spd
);
4258 mutex_unlock(&iter
->mutex
);
4263 tracing_entries_read(struct file
*filp
, char __user
*ubuf
,
4264 size_t cnt
, loff_t
*ppos
)
4266 struct trace_cpu
*tc
= filp
->private_data
;
4267 struct trace_array
*tr
= tc
->tr
;
4272 mutex_lock(&trace_types_lock
);
4274 if (tc
->cpu
== RING_BUFFER_ALL_CPUS
) {
4275 int cpu
, buf_size_same
;
4280 /* check if all cpu sizes are same */
4281 for_each_tracing_cpu(cpu
) {
4282 /* fill in the size from first enabled cpu */
4284 size
= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
;
4285 if (size
!= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
) {
4291 if (buf_size_same
) {
4292 if (!ring_buffer_expanded
)
4293 r
= sprintf(buf
, "%lu (expanded: %lu)\n",
4295 trace_buf_size
>> 10);
4297 r
= sprintf(buf
, "%lu\n", size
>> 10);
4299 r
= sprintf(buf
, "X\n");
4301 r
= sprintf(buf
, "%lu\n", per_cpu_ptr(tr
->trace_buffer
.data
, tc
->cpu
)->entries
>> 10);
4303 mutex_unlock(&trace_types_lock
);
4305 ret
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
4310 tracing_entries_write(struct file
*filp
, const char __user
*ubuf
,
4311 size_t cnt
, loff_t
*ppos
)
4313 struct trace_cpu
*tc
= filp
->private_data
;
4317 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
4321 /* must have at least 1 entry */
4325 /* value is in KB */
4328 ret
= tracing_resize_ring_buffer(tc
->tr
, val
, tc
->cpu
);
4338 tracing_total_entries_read(struct file
*filp
, char __user
*ubuf
,
4339 size_t cnt
, loff_t
*ppos
)
4341 struct trace_array
*tr
= filp
->private_data
;
4344 unsigned long size
= 0, expanded_size
= 0;
4346 mutex_lock(&trace_types_lock
);
4347 for_each_tracing_cpu(cpu
) {
4348 size
+= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
>> 10;
4349 if (!ring_buffer_expanded
)
4350 expanded_size
+= trace_buf_size
>> 10;
4352 if (ring_buffer_expanded
)
4353 r
= sprintf(buf
, "%lu\n", size
);
4355 r
= sprintf(buf
, "%lu (expanded: %lu)\n", size
, expanded_size
);
4356 mutex_unlock(&trace_types_lock
);
4358 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
4362 tracing_free_buffer_write(struct file
*filp
, const char __user
*ubuf
,
4363 size_t cnt
, loff_t
*ppos
)
4366 * There is no need to read what the user has written, this function
4367 * is just to make sure that there is no error when "echo" is used
4376 tracing_free_buffer_release(struct inode
*inode
, struct file
*filp
)
4378 struct trace_array
*tr
= inode
->i_private
;
4380 /* disable tracing ? */
4381 if (trace_flags
& TRACE_ITER_STOP_ON_FREE
)
4383 /* resize the ring buffer to 0 */
4384 tracing_resize_ring_buffer(tr
, 0, RING_BUFFER_ALL_CPUS
);
4390 tracing_mark_write(struct file
*filp
, const char __user
*ubuf
,
4391 size_t cnt
, loff_t
*fpos
)
4393 unsigned long addr
= (unsigned long)ubuf
;
4394 struct trace_array
*tr
= filp
->private_data
;
4395 struct ring_buffer_event
*event
;
4396 struct ring_buffer
*buffer
;
4397 struct print_entry
*entry
;
4398 unsigned long irq_flags
;
4399 struct page
*pages
[2];
4409 if (tracing_disabled
)
4412 if (!(trace_flags
& TRACE_ITER_MARKERS
))
4415 if (cnt
> TRACE_BUF_SIZE
)
4416 cnt
= TRACE_BUF_SIZE
;
4419 * Userspace is injecting traces into the kernel trace buffer.
4420 * We want to be as non intrusive as possible.
4421 * To do so, we do not want to allocate any special buffers
4422 * or take any locks, but instead write the userspace data
4423 * straight into the ring buffer.
4425 * First we need to pin the userspace buffer into memory,
4426 * which, most likely it is, because it just referenced it.
4427 * But there's no guarantee that it is. By using get_user_pages_fast()
4428 * and kmap_atomic/kunmap_atomic() we can get access to the
4429 * pages directly. We then write the data directly into the
4432 BUILD_BUG_ON(TRACE_BUF_SIZE
>= PAGE_SIZE
);
4434 /* check if we cross pages */
4435 if ((addr
& PAGE_MASK
) != ((addr
+ cnt
) & PAGE_MASK
))
4438 offset
= addr
& (PAGE_SIZE
- 1);
4441 ret
= get_user_pages_fast(addr
, nr_pages
, 0, pages
);
4442 if (ret
< nr_pages
) {
4444 put_page(pages
[ret
]);
4449 for (i
= 0; i
< nr_pages
; i
++)
4450 map_page
[i
] = kmap_atomic(pages
[i
]);
4452 local_save_flags(irq_flags
);
4453 size
= sizeof(*entry
) + cnt
+ 2; /* possible \n added */
4454 buffer
= tr
->trace_buffer
.buffer
;
4455 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, size
,
4456 irq_flags
, preempt_count());
4458 /* Ring buffer disabled, return as if not open for write */
4463 entry
= ring_buffer_event_data(event
);
4464 entry
->ip
= _THIS_IP_
;
4466 if (nr_pages
== 2) {
4467 len
= PAGE_SIZE
- offset
;
4468 memcpy(&entry
->buf
, map_page
[0] + offset
, len
);
4469 memcpy(&entry
->buf
[len
], map_page
[1], cnt
- len
);
4471 memcpy(&entry
->buf
, map_page
[0] + offset
, cnt
);
4473 if (entry
->buf
[cnt
- 1] != '\n') {
4474 entry
->buf
[cnt
] = '\n';
4475 entry
->buf
[cnt
+ 1] = '\0';
4477 entry
->buf
[cnt
] = '\0';
4479 __buffer_unlock_commit(buffer
, event
);
4486 for (i
= 0; i
< nr_pages
; i
++){
4487 kunmap_atomic(map_page
[i
]);
4494 static int tracing_clock_show(struct seq_file
*m
, void *v
)
4496 struct trace_array
*tr
= m
->private;
4499 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++)
4501 "%s%s%s%s", i
? " " : "",
4502 i
== tr
->clock_id
? "[" : "", trace_clocks
[i
].name
,
4503 i
== tr
->clock_id
? "]" : "");
4509 static ssize_t
tracing_clock_write(struct file
*filp
, const char __user
*ubuf
,
4510 size_t cnt
, loff_t
*fpos
)
4512 struct seq_file
*m
= filp
->private_data
;
4513 struct trace_array
*tr
= m
->private;
4515 const char *clockstr
;
4518 if (cnt
>= sizeof(buf
))
4521 if (copy_from_user(&buf
, ubuf
, cnt
))
4526 clockstr
= strstrip(buf
);
4528 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++) {
4529 if (strcmp(trace_clocks
[i
].name
, clockstr
) == 0)
4532 if (i
== ARRAY_SIZE(trace_clocks
))
4535 mutex_lock(&trace_types_lock
);
4539 ring_buffer_set_clock(tr
->trace_buffer
.buffer
, trace_clocks
[i
].func
);
4542 * New clock may not be consistent with the previous clock.
4543 * Reset the buffer so that it doesn't have incomparable timestamps.
4545 tracing_reset_online_cpus(&global_trace
.trace_buffer
);
4547 #ifdef CONFIG_TRACER_MAX_TRACE
4548 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
&& tr
->max_buffer
.buffer
)
4549 ring_buffer_set_clock(tr
->max_buffer
.buffer
, trace_clocks
[i
].func
);
4550 tracing_reset_online_cpus(&global_trace
.max_buffer
);
4553 mutex_unlock(&trace_types_lock
);
4560 static int tracing_clock_open(struct inode
*inode
, struct file
*file
)
4562 if (tracing_disabled
)
4565 return single_open(file
, tracing_clock_show
, inode
->i_private
);
4568 struct ftrace_buffer_info
{
4569 struct trace_iterator iter
;
4574 #ifdef CONFIG_TRACER_SNAPSHOT
4575 static int tracing_snapshot_open(struct inode
*inode
, struct file
*file
)
4577 struct trace_cpu
*tc
= inode
->i_private
;
4578 struct trace_iterator
*iter
;
4582 if (file
->f_mode
& FMODE_READ
) {
4583 iter
= __tracing_open(inode
, file
, true);
4585 ret
= PTR_ERR(iter
);
4587 /* Writes still need the seq_file to hold the private data */
4588 m
= kzalloc(sizeof(*m
), GFP_KERNEL
);
4591 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
4597 iter
->trace_buffer
= &tc
->tr
->max_buffer
;
4598 iter
->cpu_file
= tc
->cpu
;
4600 file
->private_data
= m
;
4607 tracing_snapshot_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
4610 struct seq_file
*m
= filp
->private_data
;
4611 struct trace_iterator
*iter
= m
->private;
4612 struct trace_array
*tr
= iter
->tr
;
4616 ret
= tracing_update_buffers();
4620 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
4624 mutex_lock(&trace_types_lock
);
4626 if (tr
->current_trace
->use_max_tr
) {
4633 if (iter
->cpu_file
!= RING_BUFFER_ALL_CPUS
) {
4637 if (tr
->allocated_snapshot
)
4641 /* Only allow per-cpu swap if the ring buffer supports it */
4642 #ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
4643 if (iter
->cpu_file
!= RING_BUFFER_ALL_CPUS
) {
4648 if (!tr
->allocated_snapshot
) {
4649 ret
= alloc_snapshot(tr
);
4653 local_irq_disable();
4654 /* Now, we're going to swap */
4655 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
)
4656 update_max_tr(tr
, current
, smp_processor_id());
4658 update_max_tr_single(tr
, current
, iter
->cpu_file
);
4662 if (tr
->allocated_snapshot
) {
4663 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
)
4664 tracing_reset_online_cpus(&tr
->max_buffer
);
4666 tracing_reset(&tr
->max_buffer
, iter
->cpu_file
);
4676 mutex_unlock(&trace_types_lock
);
4680 static int tracing_snapshot_release(struct inode
*inode
, struct file
*file
)
4682 struct seq_file
*m
= file
->private_data
;
4684 if (file
->f_mode
& FMODE_READ
)
4685 return tracing_release(inode
, file
);
4687 /* If write only, the seq_file is just a stub */
4695 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
);
4696 static ssize_t
tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
4697 size_t count
, loff_t
*ppos
);
4698 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
);
4699 static ssize_t
tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
4700 struct pipe_inode_info
*pipe
, size_t len
, unsigned int flags
);
4702 static int snapshot_raw_open(struct inode
*inode
, struct file
*filp
)
4704 struct ftrace_buffer_info
*info
;
4707 ret
= tracing_buffers_open(inode
, filp
);
4711 info
= filp
->private_data
;
4713 if (info
->iter
.trace
->use_max_tr
) {
4714 tracing_buffers_release(inode
, filp
);
4718 info
->iter
.snapshot
= true;
4719 info
->iter
.trace_buffer
= &info
->iter
.tr
->max_buffer
;
4724 #endif /* CONFIG_TRACER_SNAPSHOT */
4727 static const struct file_operations tracing_max_lat_fops
= {
4728 .open
= tracing_open_generic
,
4729 .read
= tracing_max_lat_read
,
4730 .write
= tracing_max_lat_write
,
4731 .llseek
= generic_file_llseek
,
4734 static const struct file_operations set_tracer_fops
= {
4735 .open
= tracing_open_generic
,
4736 .read
= tracing_set_trace_read
,
4737 .write
= tracing_set_trace_write
,
4738 .llseek
= generic_file_llseek
,
4741 static const struct file_operations tracing_pipe_fops
= {
4742 .open
= tracing_open_pipe
,
4743 .poll
= tracing_poll_pipe
,
4744 .read
= tracing_read_pipe
,
4745 .splice_read
= tracing_splice_read_pipe
,
4746 .release
= tracing_release_pipe
,
4747 .llseek
= no_llseek
,
4750 static const struct file_operations tracing_entries_fops
= {
4751 .open
= tracing_open_generic
,
4752 .read
= tracing_entries_read
,
4753 .write
= tracing_entries_write
,
4754 .llseek
= generic_file_llseek
,
4757 static const struct file_operations tracing_total_entries_fops
= {
4758 .open
= tracing_open_generic
,
4759 .read
= tracing_total_entries_read
,
4760 .llseek
= generic_file_llseek
,
4763 static const struct file_operations tracing_free_buffer_fops
= {
4764 .write
= tracing_free_buffer_write
,
4765 .release
= tracing_free_buffer_release
,
4768 static const struct file_operations tracing_mark_fops
= {
4769 .open
= tracing_open_generic
,
4770 .write
= tracing_mark_write
,
4771 .llseek
= generic_file_llseek
,
4774 static const struct file_operations trace_clock_fops
= {
4775 .open
= tracing_clock_open
,
4777 .llseek
= seq_lseek
,
4778 .release
= single_release
,
4779 .write
= tracing_clock_write
,
4782 #ifdef CONFIG_TRACER_SNAPSHOT
4783 static const struct file_operations snapshot_fops
= {
4784 .open
= tracing_snapshot_open
,
4786 .write
= tracing_snapshot_write
,
4787 .llseek
= tracing_seek
,
4788 .release
= tracing_snapshot_release
,
4791 static const struct file_operations snapshot_raw_fops
= {
4792 .open
= snapshot_raw_open
,
4793 .read
= tracing_buffers_read
,
4794 .release
= tracing_buffers_release
,
4795 .splice_read
= tracing_buffers_splice_read
,
4796 .llseek
= no_llseek
,
4799 #endif /* CONFIG_TRACER_SNAPSHOT */
4801 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
)
4803 struct trace_cpu
*tc
= inode
->i_private
;
4804 struct trace_array
*tr
= tc
->tr
;
4805 struct ftrace_buffer_info
*info
;
4807 if (tracing_disabled
)
4810 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
4814 mutex_lock(&trace_types_lock
);
4819 info
->iter
.cpu_file
= tc
->cpu
;
4820 info
->iter
.trace
= tr
->current_trace
;
4821 info
->iter
.trace_buffer
= &tr
->trace_buffer
;
4823 /* Force reading ring buffer for first read */
4824 info
->read
= (unsigned int)-1;
4826 filp
->private_data
= info
;
4828 mutex_unlock(&trace_types_lock
);
4830 return nonseekable_open(inode
, filp
);
4834 tracing_buffers_poll(struct file
*filp
, poll_table
*poll_table
)
4836 struct ftrace_buffer_info
*info
= filp
->private_data
;
4837 struct trace_iterator
*iter
= &info
->iter
;
4839 return trace_poll(iter
, filp
, poll_table
);
4843 tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
4844 size_t count
, loff_t
*ppos
)
4846 struct ftrace_buffer_info
*info
= filp
->private_data
;
4847 struct trace_iterator
*iter
= &info
->iter
;
4854 mutex_lock(&trace_types_lock
);
4856 #ifdef CONFIG_TRACER_MAX_TRACE
4857 if (iter
->snapshot
&& iter
->tr
->current_trace
->use_max_tr
) {
4864 info
->spare
= ring_buffer_alloc_read_page(iter
->trace_buffer
->buffer
,
4870 /* Do we have previous read data to read? */
4871 if (info
->read
< PAGE_SIZE
)
4875 trace_access_lock(iter
->cpu_file
);
4876 ret
= ring_buffer_read_page(iter
->trace_buffer
->buffer
,
4880 trace_access_unlock(iter
->cpu_file
);
4883 if (trace_empty(iter
)) {
4884 if ((filp
->f_flags
& O_NONBLOCK
)) {
4888 mutex_unlock(&trace_types_lock
);
4889 iter
->trace
->wait_pipe(iter
);
4890 mutex_lock(&trace_types_lock
);
4891 if (signal_pending(current
)) {
4903 size
= PAGE_SIZE
- info
->read
;
4907 ret
= copy_to_user(ubuf
, info
->spare
+ info
->read
, size
);
4918 mutex_unlock(&trace_types_lock
);
4923 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
)
4925 struct ftrace_buffer_info
*info
= file
->private_data
;
4926 struct trace_iterator
*iter
= &info
->iter
;
4928 mutex_lock(&trace_types_lock
);
4930 WARN_ON(!iter
->tr
->ref
);
4934 ring_buffer_free_read_page(iter
->trace_buffer
->buffer
, info
->spare
);
4937 mutex_unlock(&trace_types_lock
);
4943 struct ring_buffer
*buffer
;
4948 static void buffer_pipe_buf_release(struct pipe_inode_info
*pipe
,
4949 struct pipe_buffer
*buf
)
4951 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
4956 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
4961 static void buffer_pipe_buf_get(struct pipe_inode_info
*pipe
,
4962 struct pipe_buffer
*buf
)
4964 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
4969 /* Pipe buffer operations for a buffer. */
4970 static const struct pipe_buf_operations buffer_pipe_buf_ops
= {
4972 .map
= generic_pipe_buf_map
,
4973 .unmap
= generic_pipe_buf_unmap
,
4974 .confirm
= generic_pipe_buf_confirm
,
4975 .release
= buffer_pipe_buf_release
,
4976 .steal
= generic_pipe_buf_steal
,
4977 .get
= buffer_pipe_buf_get
,
4981 * Callback from splice_to_pipe(), if we need to release some pages
4982 * at the end of the spd in case we error'ed out in filling the pipe.
4984 static void buffer_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
4986 struct buffer_ref
*ref
=
4987 (struct buffer_ref
*)spd
->partial
[i
].private;
4992 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
4994 spd
->partial
[i
].private = 0;
4998 tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
4999 struct pipe_inode_info
*pipe
, size_t len
,
5002 struct ftrace_buffer_info
*info
= file
->private_data
;
5003 struct trace_iterator
*iter
= &info
->iter
;
5004 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
5005 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
5006 struct splice_pipe_desc spd
= {
5008 .partial
= partial_def
,
5009 .nr_pages_max
= PIPE_DEF_BUFFERS
,
5011 .ops
= &buffer_pipe_buf_ops
,
5012 .spd_release
= buffer_spd_release
,
5014 struct buffer_ref
*ref
;
5015 int entries
, size
, i
;
5018 mutex_lock(&trace_types_lock
);
5020 #ifdef CONFIG_TRACER_MAX_TRACE
5021 if (iter
->snapshot
&& iter
->tr
->current_trace
->use_max_tr
) {
5027 if (splice_grow_spd(pipe
, &spd
)) {
5032 if (*ppos
& (PAGE_SIZE
- 1)) {
5037 if (len
& (PAGE_SIZE
- 1)) {
5038 if (len
< PAGE_SIZE
) {
5046 trace_access_lock(iter
->cpu_file
);
5047 entries
= ring_buffer_entries_cpu(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
5049 for (i
= 0; i
< pipe
->buffers
&& len
&& entries
; i
++, len
-= PAGE_SIZE
) {
5053 ref
= kzalloc(sizeof(*ref
), GFP_KERNEL
);
5058 ref
->buffer
= iter
->trace_buffer
->buffer
;
5059 ref
->page
= ring_buffer_alloc_read_page(ref
->buffer
, iter
->cpu_file
);
5065 r
= ring_buffer_read_page(ref
->buffer
, &ref
->page
,
5066 len
, iter
->cpu_file
, 1);
5068 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
5074 * zero out any left over data, this is going to
5077 size
= ring_buffer_page_len(ref
->page
);
5078 if (size
< PAGE_SIZE
)
5079 memset(ref
->page
+ size
, 0, PAGE_SIZE
- size
);
5081 page
= virt_to_page(ref
->page
);
5083 spd
.pages
[i
] = page
;
5084 spd
.partial
[i
].len
= PAGE_SIZE
;
5085 spd
.partial
[i
].offset
= 0;
5086 spd
.partial
[i
].private = (unsigned long)ref
;
5090 entries
= ring_buffer_entries_cpu(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
5093 trace_access_unlock(iter
->cpu_file
);
5096 /* did we read anything? */
5097 if (!spd
.nr_pages
) {
5098 if ((file
->f_flags
& O_NONBLOCK
) || (flags
& SPLICE_F_NONBLOCK
)) {
5102 mutex_unlock(&trace_types_lock
);
5103 iter
->trace
->wait_pipe(iter
);
5104 mutex_lock(&trace_types_lock
);
5105 if (signal_pending(current
)) {
5112 ret
= splice_to_pipe(pipe
, &spd
);
5113 splice_shrink_spd(&spd
);
5115 mutex_unlock(&trace_types_lock
);
5120 static const struct file_operations tracing_buffers_fops
= {
5121 .open
= tracing_buffers_open
,
5122 .read
= tracing_buffers_read
,
5123 .poll
= tracing_buffers_poll
,
5124 .release
= tracing_buffers_release
,
5125 .splice_read
= tracing_buffers_splice_read
,
5126 .llseek
= no_llseek
,
5130 tracing_stats_read(struct file
*filp
, char __user
*ubuf
,
5131 size_t count
, loff_t
*ppos
)
5133 struct trace_cpu
*tc
= filp
->private_data
;
5134 struct trace_array
*tr
= tc
->tr
;
5135 struct trace_buffer
*trace_buf
= &tr
->trace_buffer
;
5136 struct trace_seq
*s
;
5138 unsigned long long t
;
5139 unsigned long usec_rem
;
5142 s
= kmalloc(sizeof(*s
), GFP_KERNEL
);
5148 cnt
= ring_buffer_entries_cpu(trace_buf
->buffer
, cpu
);
5149 trace_seq_printf(s
, "entries: %ld\n", cnt
);
5151 cnt
= ring_buffer_overrun_cpu(trace_buf
->buffer
, cpu
);
5152 trace_seq_printf(s
, "overrun: %ld\n", cnt
);
5154 cnt
= ring_buffer_commit_overrun_cpu(trace_buf
->buffer
, cpu
);
5155 trace_seq_printf(s
, "commit overrun: %ld\n", cnt
);
5157 cnt
= ring_buffer_bytes_cpu(trace_buf
->buffer
, cpu
);
5158 trace_seq_printf(s
, "bytes: %ld\n", cnt
);
5160 if (trace_clocks
[trace_clock_id
].in_ns
) {
5161 /* local or global for trace_clock */
5162 t
= ns2usecs(ring_buffer_oldest_event_ts(trace_buf
->buffer
, cpu
));
5163 usec_rem
= do_div(t
, USEC_PER_SEC
);
5164 trace_seq_printf(s
, "oldest event ts: %5llu.%06lu\n",
5167 t
= ns2usecs(ring_buffer_time_stamp(trace_buf
->buffer
, cpu
));
5168 usec_rem
= do_div(t
, USEC_PER_SEC
);
5169 trace_seq_printf(s
, "now ts: %5llu.%06lu\n", t
, usec_rem
);
5171 /* counter or tsc mode for trace_clock */
5172 trace_seq_printf(s
, "oldest event ts: %llu\n",
5173 ring_buffer_oldest_event_ts(trace_buf
->buffer
, cpu
));
5175 trace_seq_printf(s
, "now ts: %llu\n",
5176 ring_buffer_time_stamp(trace_buf
->buffer
, cpu
));
5179 cnt
= ring_buffer_dropped_events_cpu(trace_buf
->buffer
, cpu
);
5180 trace_seq_printf(s
, "dropped events: %ld\n", cnt
);
5182 cnt
= ring_buffer_read_events_cpu(trace_buf
->buffer
, cpu
);
5183 trace_seq_printf(s
, "read events: %ld\n", cnt
);
5185 count
= simple_read_from_buffer(ubuf
, count
, ppos
, s
->buffer
, s
->len
);
5192 static const struct file_operations tracing_stats_fops
= {
5193 .open
= tracing_open_generic
,
5194 .read
= tracing_stats_read
,
5195 .llseek
= generic_file_llseek
,
5198 #ifdef CONFIG_DYNAMIC_FTRACE
5200 int __weak
ftrace_arch_read_dyn_info(char *buf
, int size
)
5206 tracing_read_dyn_info(struct file
*filp
, char __user
*ubuf
,
5207 size_t cnt
, loff_t
*ppos
)
5209 static char ftrace_dyn_info_buffer
[1024];
5210 static DEFINE_MUTEX(dyn_info_mutex
);
5211 unsigned long *p
= filp
->private_data
;
5212 char *buf
= ftrace_dyn_info_buffer
;
5213 int size
= ARRAY_SIZE(ftrace_dyn_info_buffer
);
5216 mutex_lock(&dyn_info_mutex
);
5217 r
= sprintf(buf
, "%ld ", *p
);
5219 r
+= ftrace_arch_read_dyn_info(buf
+r
, (size
-1)-r
);
5222 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
5224 mutex_unlock(&dyn_info_mutex
);
5229 static const struct file_operations tracing_dyn_info_fops
= {
5230 .open
= tracing_open_generic
,
5231 .read
= tracing_read_dyn_info
,
5232 .llseek
= generic_file_llseek
,
5234 #endif /* CONFIG_DYNAMIC_FTRACE */
5236 #if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
5238 ftrace_snapshot(unsigned long ip
, unsigned long parent_ip
, void **data
)
5244 ftrace_count_snapshot(unsigned long ip
, unsigned long parent_ip
, void **data
)
5246 unsigned long *count
= (long *)data
;
5258 ftrace_snapshot_print(struct seq_file
*m
, unsigned long ip
,
5259 struct ftrace_probe_ops
*ops
, void *data
)
5261 long count
= (long)data
;
5263 seq_printf(m
, "%ps:", (void *)ip
);
5265 seq_printf(m
, "snapshot");
5268 seq_printf(m
, ":unlimited\n");
5270 seq_printf(m
, ":count=%ld\n", count
);
5275 static struct ftrace_probe_ops snapshot_probe_ops
= {
5276 .func
= ftrace_snapshot
,
5277 .print
= ftrace_snapshot_print
,
5280 static struct ftrace_probe_ops snapshot_count_probe_ops
= {
5281 .func
= ftrace_count_snapshot
,
5282 .print
= ftrace_snapshot_print
,
5286 ftrace_trace_snapshot_callback(struct ftrace_hash
*hash
,
5287 char *glob
, char *cmd
, char *param
, int enable
)
5289 struct ftrace_probe_ops
*ops
;
5290 void *count
= (void *)-1;
5294 /* hash funcs only work with set_ftrace_filter */
5298 ops
= param
? &snapshot_count_probe_ops
: &snapshot_probe_ops
;
5300 if (glob
[0] == '!') {
5301 unregister_ftrace_function_probe_func(glob
+1, ops
);
5308 number
= strsep(¶m
, ":");
5310 if (!strlen(number
))
5314 * We use the callback data field (which is a pointer)
5317 ret
= kstrtoul(number
, 0, (unsigned long *)&count
);
5322 ret
= register_ftrace_function_probe(glob
, ops
, count
);
5325 alloc_snapshot(&global_trace
);
5327 return ret
< 0 ? ret
: 0;
5330 static struct ftrace_func_command ftrace_snapshot_cmd
= {
5332 .func
= ftrace_trace_snapshot_callback
,
5335 static int register_snapshot_cmd(void)
5337 return register_ftrace_command(&ftrace_snapshot_cmd
);
5340 static inline int register_snapshot_cmd(void) { return 0; }
5341 #endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
5343 struct dentry
*tracing_init_dentry_tr(struct trace_array
*tr
)
5348 if (!debugfs_initialized())
5351 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
5352 tr
->dir
= debugfs_create_dir("tracing", NULL
);
5355 pr_warn_once("Could not create debugfs directory 'tracing'\n");
5360 struct dentry
*tracing_init_dentry(void)
5362 return tracing_init_dentry_tr(&global_trace
);
5365 static struct dentry
*tracing_dentry_percpu(struct trace_array
*tr
, int cpu
)
5367 struct dentry
*d_tracer
;
5370 return tr
->percpu_dir
;
5372 d_tracer
= tracing_init_dentry_tr(tr
);
5376 tr
->percpu_dir
= debugfs_create_dir("per_cpu", d_tracer
);
5378 WARN_ONCE(!tr
->percpu_dir
,
5379 "Could not create debugfs directory 'per_cpu/%d'\n", cpu
);
5381 return tr
->percpu_dir
;
5385 tracing_init_debugfs_percpu(struct trace_array
*tr
, long cpu
)
5387 struct trace_array_cpu
*data
= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
);
5388 struct dentry
*d_percpu
= tracing_dentry_percpu(tr
, cpu
);
5389 struct dentry
*d_cpu
;
5390 char cpu_dir
[30]; /* 30 characters should be more than enough */
5395 snprintf(cpu_dir
, 30, "cpu%ld", cpu
);
5396 d_cpu
= debugfs_create_dir(cpu_dir
, d_percpu
);
5398 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir
);
5402 /* per cpu trace_pipe */
5403 trace_create_file("trace_pipe", 0444, d_cpu
,
5404 (void *)&data
->trace_cpu
, &tracing_pipe_fops
);
5407 trace_create_file("trace", 0644, d_cpu
,
5408 (void *)&data
->trace_cpu
, &tracing_fops
);
5410 trace_create_file("trace_pipe_raw", 0444, d_cpu
,
5411 (void *)&data
->trace_cpu
, &tracing_buffers_fops
);
5413 trace_create_file("stats", 0444, d_cpu
,
5414 (void *)&data
->trace_cpu
, &tracing_stats_fops
);
5416 trace_create_file("buffer_size_kb", 0444, d_cpu
,
5417 (void *)&data
->trace_cpu
, &tracing_entries_fops
);
5419 #ifdef CONFIG_TRACER_SNAPSHOT
5420 trace_create_file("snapshot", 0644, d_cpu
,
5421 (void *)&data
->trace_cpu
, &snapshot_fops
);
5423 trace_create_file("snapshot_raw", 0444, d_cpu
,
5424 (void *)&data
->trace_cpu
, &snapshot_raw_fops
);
5428 #ifdef CONFIG_FTRACE_SELFTEST
5429 /* Let selftest have access to static functions in this file */
5430 #include "trace_selftest.c"
5433 struct trace_option_dentry
{
5434 struct tracer_opt
*opt
;
5435 struct tracer_flags
*flags
;
5436 struct trace_array
*tr
;
5437 struct dentry
*entry
;
5441 trace_options_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
5444 struct trace_option_dentry
*topt
= filp
->private_data
;
5447 if (topt
->flags
->val
& topt
->opt
->bit
)
5452 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
5456 trace_options_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
5459 struct trace_option_dentry
*topt
= filp
->private_data
;
5463 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5467 if (val
!= 0 && val
!= 1)
5470 if (!!(topt
->flags
->val
& topt
->opt
->bit
) != val
) {
5471 mutex_lock(&trace_types_lock
);
5472 ret
= __set_tracer_option(topt
->tr
->current_trace
, topt
->flags
,
5474 mutex_unlock(&trace_types_lock
);
5485 static const struct file_operations trace_options_fops
= {
5486 .open
= tracing_open_generic
,
5487 .read
= trace_options_read
,
5488 .write
= trace_options_write
,
5489 .llseek
= generic_file_llseek
,
5493 trace_options_core_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
5496 long index
= (long)filp
->private_data
;
5499 if (trace_flags
& (1 << index
))
5504 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
5508 trace_options_core_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
5511 struct trace_array
*tr
= &global_trace
;
5512 long index
= (long)filp
->private_data
;
5516 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5520 if (val
!= 0 && val
!= 1)
5523 mutex_lock(&trace_types_lock
);
5524 ret
= set_tracer_flag(tr
, 1 << index
, val
);
5525 mutex_unlock(&trace_types_lock
);
5535 static const struct file_operations trace_options_core_fops
= {
5536 .open
= tracing_open_generic
,
5537 .read
= trace_options_core_read
,
5538 .write
= trace_options_core_write
,
5539 .llseek
= generic_file_llseek
,
5542 struct dentry
*trace_create_file(const char *name
,
5544 struct dentry
*parent
,
5546 const struct file_operations
*fops
)
5550 ret
= debugfs_create_file(name
, mode
, parent
, data
, fops
);
5552 pr_warning("Could not create debugfs '%s' entry\n", name
);
5558 static struct dentry
*trace_options_init_dentry(struct trace_array
*tr
)
5560 struct dentry
*d_tracer
;
5565 d_tracer
= tracing_init_dentry_tr(tr
);
5569 tr
->options
= debugfs_create_dir("options", d_tracer
);
5571 pr_warning("Could not create debugfs directory 'options'\n");
5579 create_trace_option_file(struct trace_array
*tr
,
5580 struct trace_option_dentry
*topt
,
5581 struct tracer_flags
*flags
,
5582 struct tracer_opt
*opt
)
5584 struct dentry
*t_options
;
5586 t_options
= trace_options_init_dentry(tr
);
5590 topt
->flags
= flags
;
5594 topt
->entry
= trace_create_file(opt
->name
, 0644, t_options
, topt
,
5595 &trace_options_fops
);
5599 static struct trace_option_dentry
*
5600 create_trace_option_files(struct trace_array
*tr
, struct tracer
*tracer
)
5602 struct trace_option_dentry
*topts
;
5603 struct tracer_flags
*flags
;
5604 struct tracer_opt
*opts
;
5610 flags
= tracer
->flags
;
5612 if (!flags
|| !flags
->opts
)
5617 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
5620 topts
= kcalloc(cnt
+ 1, sizeof(*topts
), GFP_KERNEL
);
5624 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
5625 create_trace_option_file(tr
, &topts
[cnt
], flags
,
5632 destroy_trace_option_files(struct trace_option_dentry
*topts
)
5639 for (cnt
= 0; topts
[cnt
].opt
; cnt
++) {
5640 if (topts
[cnt
].entry
)
5641 debugfs_remove(topts
[cnt
].entry
);
5647 static struct dentry
*
5648 create_trace_option_core_file(struct trace_array
*tr
,
5649 const char *option
, long index
)
5651 struct dentry
*t_options
;
5653 t_options
= trace_options_init_dentry(tr
);
5657 return trace_create_file(option
, 0644, t_options
, (void *)index
,
5658 &trace_options_core_fops
);
5661 static __init
void create_trace_options_dir(struct trace_array
*tr
)
5663 struct dentry
*t_options
;
5666 t_options
= trace_options_init_dentry(tr
);
5670 for (i
= 0; trace_options
[i
]; i
++)
5671 create_trace_option_core_file(tr
, trace_options
[i
], i
);
5675 rb_simple_read(struct file
*filp
, char __user
*ubuf
,
5676 size_t cnt
, loff_t
*ppos
)
5678 struct trace_array
*tr
= filp
->private_data
;
5682 r
= tracer_tracing_is_on(tr
);
5683 r
= sprintf(buf
, "%d\n", r
);
5685 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
5689 rb_simple_write(struct file
*filp
, const char __user
*ubuf
,
5690 size_t cnt
, loff_t
*ppos
)
5692 struct trace_array
*tr
= filp
->private_data
;
5693 struct ring_buffer
*buffer
= tr
->trace_buffer
.buffer
;
5697 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5702 mutex_lock(&trace_types_lock
);
5704 tracer_tracing_on(tr
);
5705 if (tr
->current_trace
->start
)
5706 tr
->current_trace
->start(tr
);
5708 tracer_tracing_off(tr
);
5709 if (tr
->current_trace
->stop
)
5710 tr
->current_trace
->stop(tr
);
5712 mutex_unlock(&trace_types_lock
);
5720 static const struct file_operations rb_simple_fops
= {
5721 .open
= tracing_open_generic
,
5722 .read
= rb_simple_read
,
5723 .write
= rb_simple_write
,
5724 .llseek
= default_llseek
,
5727 struct dentry
*trace_instance_dir
;
5730 init_tracer_debugfs(struct trace_array
*tr
, struct dentry
*d_tracer
);
5732 static void init_trace_buffers(struct trace_array
*tr
, struct trace_buffer
*buf
)
5736 for_each_tracing_cpu(cpu
) {
5737 memset(per_cpu_ptr(buf
->data
, cpu
), 0, sizeof(struct trace_array_cpu
));
5738 per_cpu_ptr(buf
->data
, cpu
)->trace_cpu
.cpu
= cpu
;
5739 per_cpu_ptr(buf
->data
, cpu
)->trace_cpu
.tr
= tr
;
5744 allocate_trace_buffer(struct trace_array
*tr
, struct trace_buffer
*buf
, int size
)
5746 enum ring_buffer_flags rb_flags
;
5748 rb_flags
= trace_flags
& TRACE_ITER_OVERWRITE
? RB_FL_OVERWRITE
: 0;
5750 buf
->buffer
= ring_buffer_alloc(size
, rb_flags
);
5754 buf
->data
= alloc_percpu(struct trace_array_cpu
);
5756 ring_buffer_free(buf
->buffer
);
5760 init_trace_buffers(tr
, buf
);
5762 /* Allocate the first page for all buffers */
5763 set_buffer_entries(&tr
->trace_buffer
,
5764 ring_buffer_size(tr
->trace_buffer
.buffer
, 0));
5769 static int allocate_trace_buffers(struct trace_array
*tr
, int size
)
5773 ret
= allocate_trace_buffer(tr
, &tr
->trace_buffer
, size
);
5777 #ifdef CONFIG_TRACER_MAX_TRACE
5778 ret
= allocate_trace_buffer(tr
, &tr
->max_buffer
,
5779 allocate_snapshot
? size
: 1);
5781 ring_buffer_free(tr
->trace_buffer
.buffer
);
5782 free_percpu(tr
->trace_buffer
.data
);
5785 tr
->allocated_snapshot
= allocate_snapshot
;
5788 * Only the top level trace array gets its snapshot allocated
5789 * from the kernel command line.
5791 allocate_snapshot
= false;
5796 static int new_instance_create(const char *name
)
5798 struct trace_array
*tr
;
5801 mutex_lock(&trace_types_lock
);
5804 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
5805 if (tr
->name
&& strcmp(tr
->name
, name
) == 0)
5810 tr
= kzalloc(sizeof(*tr
), GFP_KERNEL
);
5814 tr
->name
= kstrdup(name
, GFP_KERNEL
);
5818 raw_spin_lock_init(&tr
->start_lock
);
5820 tr
->current_trace
= &nop_trace
;
5822 INIT_LIST_HEAD(&tr
->systems
);
5823 INIT_LIST_HEAD(&tr
->events
);
5825 if (allocate_trace_buffers(tr
, trace_buf_size
) < 0)
5828 /* Holder for file callbacks */
5829 tr
->trace_cpu
.cpu
= RING_BUFFER_ALL_CPUS
;
5830 tr
->trace_cpu
.tr
= tr
;
5832 tr
->dir
= debugfs_create_dir(name
, trace_instance_dir
);
5836 ret
= event_trace_add_tracer(tr
->dir
, tr
);
5840 init_tracer_debugfs(tr
, tr
->dir
);
5842 list_add(&tr
->list
, &ftrace_trace_arrays
);
5844 mutex_unlock(&trace_types_lock
);
5849 if (tr
->trace_buffer
.buffer
)
5850 ring_buffer_free(tr
->trace_buffer
.buffer
);
5855 mutex_unlock(&trace_types_lock
);
5861 static int instance_delete(const char *name
)
5863 struct trace_array
*tr
;
5867 mutex_lock(&trace_types_lock
);
5870 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
5871 if (tr
->name
&& strcmp(tr
->name
, name
) == 0) {
5883 list_del(&tr
->list
);
5885 event_trace_del_tracer(tr
);
5886 debugfs_remove_recursive(tr
->dir
);
5887 free_percpu(tr
->trace_buffer
.data
);
5888 ring_buffer_free(tr
->trace_buffer
.buffer
);
5896 mutex_unlock(&trace_types_lock
);
5901 static int instance_mkdir (struct inode
*inode
, struct dentry
*dentry
, umode_t mode
)
5903 struct dentry
*parent
;
5906 /* Paranoid: Make sure the parent is the "instances" directory */
5907 parent
= hlist_entry(inode
->i_dentry
.first
, struct dentry
, d_alias
);
5908 if (WARN_ON_ONCE(parent
!= trace_instance_dir
))
5912 * The inode mutex is locked, but debugfs_create_dir() will also
5913 * take the mutex. As the instances directory can not be destroyed
5914 * or changed in any other way, it is safe to unlock it, and
5915 * let the dentry try. If two users try to make the same dir at
5916 * the same time, then the new_instance_create() will determine the
5919 mutex_unlock(&inode
->i_mutex
);
5921 ret
= new_instance_create(dentry
->d_iname
);
5923 mutex_lock(&inode
->i_mutex
);
5928 static int instance_rmdir(struct inode
*inode
, struct dentry
*dentry
)
5930 struct dentry
*parent
;
5933 /* Paranoid: Make sure the parent is the "instances" directory */
5934 parent
= hlist_entry(inode
->i_dentry
.first
, struct dentry
, d_alias
);
5935 if (WARN_ON_ONCE(parent
!= trace_instance_dir
))
5938 /* The caller did a dget() on dentry */
5939 mutex_unlock(&dentry
->d_inode
->i_mutex
);
5942 * The inode mutex is locked, but debugfs_create_dir() will also
5943 * take the mutex. As the instances directory can not be destroyed
5944 * or changed in any other way, it is safe to unlock it, and
5945 * let the dentry try. If two users try to make the same dir at
5946 * the same time, then the instance_delete() will determine the
5949 mutex_unlock(&inode
->i_mutex
);
5951 ret
= instance_delete(dentry
->d_iname
);
5953 mutex_lock_nested(&inode
->i_mutex
, I_MUTEX_PARENT
);
5954 mutex_lock(&dentry
->d_inode
->i_mutex
);
5959 static const struct inode_operations instance_dir_inode_operations
= {
5960 .lookup
= simple_lookup
,
5961 .mkdir
= instance_mkdir
,
5962 .rmdir
= instance_rmdir
,
5965 static __init
void create_trace_instances(struct dentry
*d_tracer
)
5967 trace_instance_dir
= debugfs_create_dir("instances", d_tracer
);
5968 if (WARN_ON(!trace_instance_dir
))
5971 /* Hijack the dir inode operations, to allow mkdir */
5972 trace_instance_dir
->d_inode
->i_op
= &instance_dir_inode_operations
;
5976 init_tracer_debugfs(struct trace_array
*tr
, struct dentry
*d_tracer
)
5980 trace_create_file("trace_options", 0644, d_tracer
,
5981 tr
, &tracing_iter_fops
);
5983 trace_create_file("trace", 0644, d_tracer
,
5984 (void *)&tr
->trace_cpu
, &tracing_fops
);
5986 trace_create_file("trace_pipe", 0444, d_tracer
,
5987 (void *)&tr
->trace_cpu
, &tracing_pipe_fops
);
5989 trace_create_file("buffer_size_kb", 0644, d_tracer
,
5990 (void *)&tr
->trace_cpu
, &tracing_entries_fops
);
5992 trace_create_file("buffer_total_size_kb", 0444, d_tracer
,
5993 tr
, &tracing_total_entries_fops
);
5995 trace_create_file("free_buffer", 0200, d_tracer
,
5996 tr
, &tracing_free_buffer_fops
);
5998 trace_create_file("trace_marker", 0220, d_tracer
,
5999 tr
, &tracing_mark_fops
);
6001 trace_create_file("trace_clock", 0644, d_tracer
, tr
,
6004 trace_create_file("tracing_on", 0644, d_tracer
,
6005 tr
, &rb_simple_fops
);
6007 #ifdef CONFIG_TRACER_SNAPSHOT
6008 trace_create_file("snapshot", 0644, d_tracer
,
6009 (void *)&tr
->trace_cpu
, &snapshot_fops
);
6012 for_each_tracing_cpu(cpu
)
6013 tracing_init_debugfs_percpu(tr
, cpu
);
6017 static __init
int tracer_init_debugfs(void)
6019 struct dentry
*d_tracer
;
6021 trace_access_lock_init();
6023 d_tracer
= tracing_init_dentry();
6027 init_tracer_debugfs(&global_trace
, d_tracer
);
6029 trace_create_file("tracing_cpumask", 0644, d_tracer
,
6030 &global_trace
, &tracing_cpumask_fops
);
6032 trace_create_file("available_tracers", 0444, d_tracer
,
6033 &global_trace
, &show_traces_fops
);
6035 trace_create_file("current_tracer", 0644, d_tracer
,
6036 &global_trace
, &set_tracer_fops
);
6038 #ifdef CONFIG_TRACER_MAX_TRACE
6039 trace_create_file("tracing_max_latency", 0644, d_tracer
,
6040 &tracing_max_latency
, &tracing_max_lat_fops
);
6043 trace_create_file("tracing_thresh", 0644, d_tracer
,
6044 &tracing_thresh
, &tracing_max_lat_fops
);
6046 trace_create_file("README", 0444, d_tracer
,
6047 NULL
, &tracing_readme_fops
);
6049 trace_create_file("saved_cmdlines", 0444, d_tracer
,
6050 NULL
, &tracing_saved_cmdlines_fops
);
6052 #ifdef CONFIG_DYNAMIC_FTRACE
6053 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
6054 &ftrace_update_tot_cnt
, &tracing_dyn_info_fops
);
6057 create_trace_instances(d_tracer
);
6059 create_trace_options_dir(&global_trace
);
6064 static int trace_panic_handler(struct notifier_block
*this,
6065 unsigned long event
, void *unused
)
6067 if (ftrace_dump_on_oops
)
6068 ftrace_dump(ftrace_dump_on_oops
);
6072 static struct notifier_block trace_panic_notifier
= {
6073 .notifier_call
= trace_panic_handler
,
6075 .priority
= 150 /* priority: INT_MAX >= x >= 0 */
6078 static int trace_die_handler(struct notifier_block
*self
,
6084 if (ftrace_dump_on_oops
)
6085 ftrace_dump(ftrace_dump_on_oops
);
6093 static struct notifier_block trace_die_notifier
= {
6094 .notifier_call
= trace_die_handler
,
6099 * printk is set to max of 1024, we really don't need it that big.
6100 * Nothing should be printing 1000 characters anyway.
6102 #define TRACE_MAX_PRINT 1000
6105 * Define here KERN_TRACE so that we have one place to modify
6106 * it if we decide to change what log level the ftrace dump
6109 #define KERN_TRACE KERN_EMERG
6112 trace_printk_seq(struct trace_seq
*s
)
6114 /* Probably should print a warning here. */
6115 if (s
->len
>= TRACE_MAX_PRINT
)
6116 s
->len
= TRACE_MAX_PRINT
;
6118 /* should be zero ended, but we are paranoid. */
6119 s
->buffer
[s
->len
] = 0;
6121 printk(KERN_TRACE
"%s", s
->buffer
);
6126 void trace_init_global_iter(struct trace_iterator
*iter
)
6128 iter
->tr
= &global_trace
;
6129 iter
->trace
= iter
->tr
->current_trace
;
6130 iter
->cpu_file
= RING_BUFFER_ALL_CPUS
;
6131 iter
->trace_buffer
= &global_trace
.trace_buffer
;
6134 void ftrace_dump(enum ftrace_dump_mode oops_dump_mode
)
6136 /* use static because iter can be a bit big for the stack */
6137 static struct trace_iterator iter
;
6138 static atomic_t dump_running
;
6139 unsigned int old_userobj
;
6140 unsigned long flags
;
6143 /* Only allow one dump user at a time. */
6144 if (atomic_inc_return(&dump_running
) != 1) {
6145 atomic_dec(&dump_running
);
6150 * Always turn off tracing when we dump.
6151 * We don't need to show trace output of what happens
6152 * between multiple crashes.
6154 * If the user does a sysrq-z, then they can re-enable
6155 * tracing with echo 1 > tracing_on.
6159 local_irq_save(flags
);
6161 /* Simulate the iterator */
6162 trace_init_global_iter(&iter
);
6164 for_each_tracing_cpu(cpu
) {
6165 atomic_inc(&per_cpu_ptr(iter
.tr
->trace_buffer
.data
, cpu
)->disabled
);
6168 old_userobj
= trace_flags
& TRACE_ITER_SYM_USEROBJ
;
6170 /* don't look at user memory in panic mode */
6171 trace_flags
&= ~TRACE_ITER_SYM_USEROBJ
;
6173 switch (oops_dump_mode
) {
6175 iter
.cpu_file
= RING_BUFFER_ALL_CPUS
;
6178 iter
.cpu_file
= raw_smp_processor_id();
6183 printk(KERN_TRACE
"Bad dumping mode, switching to all CPUs dump\n");
6184 iter
.cpu_file
= RING_BUFFER_ALL_CPUS
;
6187 printk(KERN_TRACE
"Dumping ftrace buffer:\n");
6189 /* Did function tracer already get disabled? */
6190 if (ftrace_is_dead()) {
6191 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
6192 printk("# MAY BE MISSING FUNCTION EVENTS\n");
6196 * We need to stop all tracing on all CPUS to read the
6197 * the next buffer. This is a bit expensive, but is
6198 * not done often. We fill all what we can read,
6199 * and then release the locks again.
6202 while (!trace_empty(&iter
)) {
6205 printk(KERN_TRACE
"---------------------------------\n");
6209 /* reset all but tr, trace, and overruns */
6210 memset(&iter
.seq
, 0,
6211 sizeof(struct trace_iterator
) -
6212 offsetof(struct trace_iterator
, seq
));
6213 iter
.iter_flags
|= TRACE_FILE_LAT_FMT
;
6216 if (trace_find_next_entry_inc(&iter
) != NULL
) {
6219 ret
= print_trace_line(&iter
);
6220 if (ret
!= TRACE_TYPE_NO_CONSUME
)
6221 trace_consume(&iter
);
6223 touch_nmi_watchdog();
6225 trace_printk_seq(&iter
.seq
);
6229 printk(KERN_TRACE
" (ftrace buffer empty)\n");
6231 printk(KERN_TRACE
"---------------------------------\n");
6234 trace_flags
|= old_userobj
;
6236 for_each_tracing_cpu(cpu
) {
6237 atomic_dec(&per_cpu_ptr(iter
.trace_buffer
->data
, cpu
)->disabled
);
6239 atomic_dec(&dump_running
);
6240 local_irq_restore(flags
);
6242 EXPORT_SYMBOL_GPL(ftrace_dump
);
6244 __init
static int tracer_alloc_buffers(void)
6250 if (!alloc_cpumask_var(&tracing_buffer_mask
, GFP_KERNEL
))
6253 if (!alloc_cpumask_var(&tracing_cpumask
, GFP_KERNEL
))
6254 goto out_free_buffer_mask
;
6256 /* Only allocate trace_printk buffers if a trace_printk exists */
6257 if (__stop___trace_bprintk_fmt
!= __start___trace_bprintk_fmt
)
6258 /* Must be called before global_trace.buffer is allocated */
6259 trace_printk_init_buffers();
6261 /* To save memory, keep the ring buffer size to its minimum */
6262 if (ring_buffer_expanded
)
6263 ring_buf_size
= trace_buf_size
;
6267 cpumask_copy(tracing_buffer_mask
, cpu_possible_mask
);
6268 cpumask_copy(tracing_cpumask
, cpu_all_mask
);
6270 raw_spin_lock_init(&global_trace
.start_lock
);
6272 /* TODO: make the number of buffers hot pluggable with CPUS */
6273 if (allocate_trace_buffers(&global_trace
, ring_buf_size
) < 0) {
6274 printk(KERN_ERR
"tracer: failed to allocate ring buffer!\n");
6276 goto out_free_cpumask
;
6279 if (global_trace
.buffer_disabled
)
6282 trace_init_cmdlines();
6285 * register_tracer() might reference current_trace, so it
6286 * needs to be set before we register anything. This is
6287 * just a bootstrap of current_trace anyway.
6289 global_trace
.current_trace
= &nop_trace
;
6291 register_tracer(&nop_trace
);
6293 /* All seems OK, enable tracing */
6294 tracing_disabled
= 0;
6296 atomic_notifier_chain_register(&panic_notifier_list
,
6297 &trace_panic_notifier
);
6299 register_die_notifier(&trace_die_notifier
);
6301 global_trace
.flags
= TRACE_ARRAY_FL_GLOBAL
;
6303 /* Holder for file callbacks */
6304 global_trace
.trace_cpu
.cpu
= RING_BUFFER_ALL_CPUS
;
6305 global_trace
.trace_cpu
.tr
= &global_trace
;
6307 INIT_LIST_HEAD(&global_trace
.systems
);
6308 INIT_LIST_HEAD(&global_trace
.events
);
6309 list_add(&global_trace
.list
, &ftrace_trace_arrays
);
6311 while (trace_boot_options
) {
6314 option
= strsep(&trace_boot_options
, ",");
6315 trace_set_options(&global_trace
, option
);
6318 register_snapshot_cmd();
6323 free_percpu(global_trace
.trace_buffer
.data
);
6324 #ifdef CONFIG_TRACER_MAX_TRACE
6325 free_percpu(global_trace
.max_buffer
.data
);
6327 free_cpumask_var(tracing_cpumask
);
6328 out_free_buffer_mask
:
6329 free_cpumask_var(tracing_buffer_mask
);
6334 __init
static int clear_boot_tracer(void)
6337 * The default tracer at boot buffer is an init section.
6338 * This function is called in lateinit. If we did not
6339 * find the boot tracer, then clear it out, to prevent
6340 * later registration from accessing the buffer that is
6341 * about to be freed.
6343 if (!default_bootup_tracer
)
6346 printk(KERN_INFO
"ftrace bootup tracer '%s' not registered.\n",
6347 default_bootup_tracer
);
6348 default_bootup_tracer
= NULL
;
6353 early_initcall(tracer_alloc_buffers
);
6354 fs_initcall(tracer_init_debugfs
);
6355 late_initcall(clear_boot_tracer
);