2 * ring buffer based function tracer
4 * Copyright (C) 2007-2012 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
7 * Originally taken from the RT patch by:
8 * Arnaldo Carvalho de Melo <acme@redhat.com>
10 * Based on code from the latency_tracer, that is:
11 * Copyright (C) 2004-2006 Ingo Molnar
12 * Copyright (C) 2004 Nadia Yvette Chambers
14 #include <linux/ring_buffer.h>
15 #include <generated/utsrelease.h>
16 #include <linux/stacktrace.h>
17 #include <linux/writeback.h>
18 #include <linux/kallsyms.h>
19 #include <linux/seq_file.h>
20 #include <linux/notifier.h>
21 #include <linux/irqflags.h>
22 #include <linux/debugfs.h>
23 #include <linux/pagemap.h>
24 #include <linux/hardirq.h>
25 #include <linux/linkage.h>
26 #include <linux/uaccess.h>
27 #include <linux/kprobes.h>
28 #include <linux/ftrace.h>
29 #include <linux/module.h>
30 #include <linux/percpu.h>
31 #include <linux/splice.h>
32 #include <linux/kdebug.h>
33 #include <linux/string.h>
34 #include <linux/rwsem.h>
35 #include <linux/slab.h>
36 #include <linux/ctype.h>
37 #include <linux/init.h>
38 #include <linux/poll.h>
39 #include <linux/nmi.h>
41 #include <linux/sched/rt.h>
44 #include "trace_output.h"
47 * On boot up, the ring buffer is set to the minimum size, so that
48 * we do not waste memory on systems that are not using tracing.
50 bool ring_buffer_expanded
;
53 * We need to change this state when a selftest is running.
54 * A selftest will lurk into the ring-buffer to count the
55 * entries inserted during the selftest although some concurrent
56 * insertions into the ring-buffer such as trace_printk could occurred
57 * at the same time, giving false positive or negative results.
59 static bool __read_mostly tracing_selftest_running
;
62 * If a tracer is running, we do not want to run SELFTEST.
64 bool __read_mostly tracing_selftest_disabled
;
66 /* For tracers that don't implement custom flags */
67 static struct tracer_opt dummy_tracer_opt
[] = {
71 static struct tracer_flags dummy_tracer_flags
= {
73 .opts
= dummy_tracer_opt
76 static int dummy_set_flag(u32 old_flags
, u32 bit
, int set
)
82 * To prevent the comm cache from being overwritten when no
83 * tracing is active, only save the comm when a trace event
86 static DEFINE_PER_CPU(bool, trace_cmdline_save
);
89 * Kill all tracing for good (never come back).
90 * It is initialized to 1 but will turn to zero if the initialization
91 * of the tracer is successful. But that is the only place that sets
94 static int tracing_disabled
= 1;
96 DEFINE_PER_CPU(int, ftrace_cpu_disabled
);
98 cpumask_var_t __read_mostly tracing_buffer_mask
;
101 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
103 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
104 * is set, then ftrace_dump is called. This will output the contents
105 * of the ftrace buffers to the console. This is very useful for
106 * capturing traces that lead to crashes and outputing it to a
109 * It is default off, but you can enable it with either specifying
110 * "ftrace_dump_on_oops" in the kernel command line, or setting
111 * /proc/sys/kernel/ftrace_dump_on_oops
112 * Set 1 if you want to dump buffers of all CPUs
113 * Set 2 if you want to dump the buffer of the CPU that triggered oops
116 enum ftrace_dump_mode ftrace_dump_on_oops
;
118 /* When set, tracing will stop when a WARN*() is hit */
119 int __disable_trace_on_warning
;
121 static int tracing_set_tracer(const char *buf
);
123 #define MAX_TRACER_SIZE 100
124 static char bootup_tracer_buf
[MAX_TRACER_SIZE
] __initdata
;
125 static char *default_bootup_tracer
;
127 static bool allocate_snapshot
;
129 static int __init
set_cmdline_ftrace(char *str
)
131 strlcpy(bootup_tracer_buf
, str
, MAX_TRACER_SIZE
);
132 default_bootup_tracer
= bootup_tracer_buf
;
133 /* We are using ftrace early, expand it */
134 ring_buffer_expanded
= true;
137 __setup("ftrace=", set_cmdline_ftrace
);
139 static int __init
set_ftrace_dump_on_oops(char *str
)
141 if (*str
++ != '=' || !*str
) {
142 ftrace_dump_on_oops
= DUMP_ALL
;
146 if (!strcmp("orig_cpu", str
)) {
147 ftrace_dump_on_oops
= DUMP_ORIG
;
153 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops
);
155 static int __init
stop_trace_on_warning(char *str
)
157 __disable_trace_on_warning
= 1;
160 __setup("traceoff_on_warning=", stop_trace_on_warning
);
162 static int __init
boot_alloc_snapshot(char *str
)
164 allocate_snapshot
= true;
165 /* We also need the main ring buffer expanded */
166 ring_buffer_expanded
= true;
169 __setup("alloc_snapshot", boot_alloc_snapshot
);
172 static char trace_boot_options_buf
[MAX_TRACER_SIZE
] __initdata
;
173 static char *trace_boot_options __initdata
;
175 static int __init
set_trace_boot_options(char *str
)
177 strlcpy(trace_boot_options_buf
, str
, MAX_TRACER_SIZE
);
178 trace_boot_options
= trace_boot_options_buf
;
181 __setup("trace_options=", set_trace_boot_options
);
184 unsigned long long ns2usecs(cycle_t nsec
)
192 * The global_trace is the descriptor that holds the tracing
193 * buffers for the live tracing. For each CPU, it contains
194 * a link list of pages that will store trace entries. The
195 * page descriptor of the pages in the memory is used to hold
196 * the link list by linking the lru item in the page descriptor
197 * to each of the pages in the buffer per CPU.
199 * For each active CPU there is a data field that holds the
200 * pages for the buffer for that CPU. Each CPU has the same number
201 * of pages allocated for its buffer.
203 static struct trace_array global_trace
;
205 LIST_HEAD(ftrace_trace_arrays
);
207 int trace_array_get(struct trace_array
*this_tr
)
209 struct trace_array
*tr
;
212 mutex_lock(&trace_types_lock
);
213 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
220 mutex_unlock(&trace_types_lock
);
225 static void __trace_array_put(struct trace_array
*this_tr
)
227 WARN_ON(!this_tr
->ref
);
231 void trace_array_put(struct trace_array
*this_tr
)
233 mutex_lock(&trace_types_lock
);
234 __trace_array_put(this_tr
);
235 mutex_unlock(&trace_types_lock
);
238 int filter_check_discard(struct ftrace_event_file
*file
, void *rec
,
239 struct ring_buffer
*buffer
,
240 struct ring_buffer_event
*event
)
242 if (unlikely(file
->flags
& FTRACE_EVENT_FL_FILTERED
) &&
243 !filter_match_preds(file
->filter
, rec
)) {
244 ring_buffer_discard_commit(buffer
, event
);
250 EXPORT_SYMBOL_GPL(filter_check_discard
);
252 int call_filter_check_discard(struct ftrace_event_call
*call
, void *rec
,
253 struct ring_buffer
*buffer
,
254 struct ring_buffer_event
*event
)
256 if (unlikely(call
->flags
& TRACE_EVENT_FL_FILTERED
) &&
257 !filter_match_preds(call
->filter
, rec
)) {
258 ring_buffer_discard_commit(buffer
, event
);
264 EXPORT_SYMBOL_GPL(call_filter_check_discard
);
266 cycle_t
buffer_ftrace_now(struct trace_buffer
*buf
, int cpu
)
270 /* Early boot up does not have a buffer yet */
272 return trace_clock_local();
274 ts
= ring_buffer_time_stamp(buf
->buffer
, cpu
);
275 ring_buffer_normalize_time_stamp(buf
->buffer
, cpu
, &ts
);
280 cycle_t
ftrace_now(int cpu
)
282 return buffer_ftrace_now(&global_trace
.trace_buffer
, cpu
);
286 * tracing_is_enabled - Show if global_trace has been disabled
288 * Shows if the global trace has been enabled or not. It uses the
289 * mirror flag "buffer_disabled" to be used in fast paths such as for
290 * the irqsoff tracer. But it may be inaccurate due to races. If you
291 * need to know the accurate state, use tracing_is_on() which is a little
292 * slower, but accurate.
294 int tracing_is_enabled(void)
297 * For quick access (irqsoff uses this in fast path), just
298 * return the mirror variable of the state of the ring buffer.
299 * It's a little racy, but we don't really care.
302 return !global_trace
.buffer_disabled
;
306 * trace_buf_size is the size in bytes that is allocated
307 * for a buffer. Note, the number of bytes is always rounded
310 * This number is purposely set to a low number of 16384.
311 * If the dump on oops happens, it will be much appreciated
312 * to not have to wait for all that output. Anyway this can be
313 * boot time and run time configurable.
315 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
317 static unsigned long trace_buf_size
= TRACE_BUF_SIZE_DEFAULT
;
319 /* trace_types holds a link list of available tracers. */
320 static struct tracer
*trace_types __read_mostly
;
323 * trace_types_lock is used to protect the trace_types list.
325 DEFINE_MUTEX(trace_types_lock
);
328 * serialize the access of the ring buffer
330 * ring buffer serializes readers, but it is low level protection.
331 * The validity of the events (which returns by ring_buffer_peek() ..etc)
332 * are not protected by ring buffer.
334 * The content of events may become garbage if we allow other process consumes
335 * these events concurrently:
336 * A) the page of the consumed events may become a normal page
337 * (not reader page) in ring buffer, and this page will be rewrited
338 * by events producer.
339 * B) The page of the consumed events may become a page for splice_read,
340 * and this page will be returned to system.
342 * These primitives allow multi process access to different cpu ring buffer
345 * These primitives don't distinguish read-only and read-consume access.
346 * Multi read-only access are also serialized.
350 static DECLARE_RWSEM(all_cpu_access_lock
);
351 static DEFINE_PER_CPU(struct mutex
, cpu_access_lock
);
353 static inline void trace_access_lock(int cpu
)
355 if (cpu
== RING_BUFFER_ALL_CPUS
) {
356 /* gain it for accessing the whole ring buffer. */
357 down_write(&all_cpu_access_lock
);
359 /* gain it for accessing a cpu ring buffer. */
361 /* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
362 down_read(&all_cpu_access_lock
);
364 /* Secondly block other access to this @cpu ring buffer. */
365 mutex_lock(&per_cpu(cpu_access_lock
, cpu
));
369 static inline void trace_access_unlock(int cpu
)
371 if (cpu
== RING_BUFFER_ALL_CPUS
) {
372 up_write(&all_cpu_access_lock
);
374 mutex_unlock(&per_cpu(cpu_access_lock
, cpu
));
375 up_read(&all_cpu_access_lock
);
379 static inline void trace_access_lock_init(void)
383 for_each_possible_cpu(cpu
)
384 mutex_init(&per_cpu(cpu_access_lock
, cpu
));
389 static DEFINE_MUTEX(access_lock
);
391 static inline void trace_access_lock(int cpu
)
394 mutex_lock(&access_lock
);
397 static inline void trace_access_unlock(int cpu
)
400 mutex_unlock(&access_lock
);
403 static inline void trace_access_lock_init(void)
409 /* trace_flags holds trace_options default values */
410 unsigned long trace_flags
= TRACE_ITER_PRINT_PARENT
| TRACE_ITER_PRINTK
|
411 TRACE_ITER_ANNOTATE
| TRACE_ITER_CONTEXT_INFO
| TRACE_ITER_SLEEP_TIME
|
412 TRACE_ITER_GRAPH_TIME
| TRACE_ITER_RECORD_CMD
| TRACE_ITER_OVERWRITE
|
413 TRACE_ITER_IRQ_INFO
| TRACE_ITER_MARKERS
| TRACE_ITER_FUNCTION
;
415 static void tracer_tracing_on(struct trace_array
*tr
)
417 if (tr
->trace_buffer
.buffer
)
418 ring_buffer_record_on(tr
->trace_buffer
.buffer
);
420 * This flag is looked at when buffers haven't been allocated
421 * yet, or by some tracers (like irqsoff), that just want to
422 * know if the ring buffer has been disabled, but it can handle
423 * races of where it gets disabled but we still do a record.
424 * As the check is in the fast path of the tracers, it is more
425 * important to be fast than accurate.
427 tr
->buffer_disabled
= 0;
428 /* Make the flag seen by readers */
433 * tracing_on - enable tracing buffers
435 * This function enables tracing buffers that may have been
436 * disabled with tracing_off.
438 void tracing_on(void)
440 tracer_tracing_on(&global_trace
);
442 EXPORT_SYMBOL_GPL(tracing_on
);
445 * __trace_puts - write a constant string into the trace buffer.
446 * @ip: The address of the caller
447 * @str: The constant string to write
448 * @size: The size of the string.
450 int __trace_puts(unsigned long ip
, const char *str
, int size
)
452 struct ring_buffer_event
*event
;
453 struct ring_buffer
*buffer
;
454 struct print_entry
*entry
;
455 unsigned long irq_flags
;
458 alloc
= sizeof(*entry
) + size
+ 2; /* possible \n added */
460 local_save_flags(irq_flags
);
461 buffer
= global_trace
.trace_buffer
.buffer
;
462 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, alloc
,
463 irq_flags
, preempt_count());
467 entry
= ring_buffer_event_data(event
);
470 memcpy(&entry
->buf
, str
, size
);
472 /* Add a newline if necessary */
473 if (entry
->buf
[size
- 1] != '\n') {
474 entry
->buf
[size
] = '\n';
475 entry
->buf
[size
+ 1] = '\0';
477 entry
->buf
[size
] = '\0';
479 __buffer_unlock_commit(buffer
, event
);
483 EXPORT_SYMBOL_GPL(__trace_puts
);
486 * __trace_bputs - write the pointer to a constant string into trace buffer
487 * @ip: The address of the caller
488 * @str: The constant string to write to the buffer to
490 int __trace_bputs(unsigned long ip
, const char *str
)
492 struct ring_buffer_event
*event
;
493 struct ring_buffer
*buffer
;
494 struct bputs_entry
*entry
;
495 unsigned long irq_flags
;
496 int size
= sizeof(struct bputs_entry
);
498 local_save_flags(irq_flags
);
499 buffer
= global_trace
.trace_buffer
.buffer
;
500 event
= trace_buffer_lock_reserve(buffer
, TRACE_BPUTS
, size
,
501 irq_flags
, preempt_count());
505 entry
= ring_buffer_event_data(event
);
509 __buffer_unlock_commit(buffer
, event
);
513 EXPORT_SYMBOL_GPL(__trace_bputs
);
515 #ifdef CONFIG_TRACER_SNAPSHOT
517 * trace_snapshot - take a snapshot of the current buffer.
519 * This causes a swap between the snapshot buffer and the current live
520 * tracing buffer. You can use this to take snapshots of the live
521 * trace when some condition is triggered, but continue to trace.
523 * Note, make sure to allocate the snapshot with either
524 * a tracing_snapshot_alloc(), or by doing it manually
525 * with: echo 1 > /sys/kernel/debug/tracing/snapshot
527 * If the snapshot buffer is not allocated, it will stop tracing.
528 * Basically making a permanent snapshot.
530 void tracing_snapshot(void)
532 struct trace_array
*tr
= &global_trace
;
533 struct tracer
*tracer
= tr
->current_trace
;
537 internal_trace_puts("*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
538 internal_trace_puts("*** snapshot is being ignored ***\n");
542 if (!tr
->allocated_snapshot
) {
543 internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n");
544 internal_trace_puts("*** stopping trace here! ***\n");
549 /* Note, snapshot can not be used when the tracer uses it */
550 if (tracer
->use_max_tr
) {
551 internal_trace_puts("*** LATENCY TRACER ACTIVE ***\n");
552 internal_trace_puts("*** Can not use snapshot (sorry) ***\n");
556 local_irq_save(flags
);
557 update_max_tr(tr
, current
, smp_processor_id());
558 local_irq_restore(flags
);
560 EXPORT_SYMBOL_GPL(tracing_snapshot
);
562 static int resize_buffer_duplicate_size(struct trace_buffer
*trace_buf
,
563 struct trace_buffer
*size_buf
, int cpu_id
);
564 static void set_buffer_entries(struct trace_buffer
*buf
, unsigned long val
);
566 static int alloc_snapshot(struct trace_array
*tr
)
570 if (!tr
->allocated_snapshot
) {
572 /* allocate spare buffer */
573 ret
= resize_buffer_duplicate_size(&tr
->max_buffer
,
574 &tr
->trace_buffer
, RING_BUFFER_ALL_CPUS
);
578 tr
->allocated_snapshot
= true;
584 void free_snapshot(struct trace_array
*tr
)
587 * We don't free the ring buffer. instead, resize it because
588 * The max_tr ring buffer has some state (e.g. ring->clock) and
589 * we want preserve it.
591 ring_buffer_resize(tr
->max_buffer
.buffer
, 1, RING_BUFFER_ALL_CPUS
);
592 set_buffer_entries(&tr
->max_buffer
, 1);
593 tracing_reset_online_cpus(&tr
->max_buffer
);
594 tr
->allocated_snapshot
= false;
598 * trace_snapshot_alloc - allocate and take a snapshot of the current buffer.
600 * This is similar to trace_snapshot(), but it will allocate the
601 * snapshot buffer if it isn't already allocated. Use this only
602 * where it is safe to sleep, as the allocation may sleep.
604 * This causes a swap between the snapshot buffer and the current live
605 * tracing buffer. You can use this to take snapshots of the live
606 * trace when some condition is triggered, but continue to trace.
608 void tracing_snapshot_alloc(void)
610 struct trace_array
*tr
= &global_trace
;
613 ret
= alloc_snapshot(tr
);
614 if (WARN_ON(ret
< 0))
619 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc
);
621 void tracing_snapshot(void)
623 WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
625 EXPORT_SYMBOL_GPL(tracing_snapshot
);
626 void tracing_snapshot_alloc(void)
631 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc
);
632 #endif /* CONFIG_TRACER_SNAPSHOT */
634 static void tracer_tracing_off(struct trace_array
*tr
)
636 if (tr
->trace_buffer
.buffer
)
637 ring_buffer_record_off(tr
->trace_buffer
.buffer
);
639 * This flag is looked at when buffers haven't been allocated
640 * yet, or by some tracers (like irqsoff), that just want to
641 * know if the ring buffer has been disabled, but it can handle
642 * races of where it gets disabled but we still do a record.
643 * As the check is in the fast path of the tracers, it is more
644 * important to be fast than accurate.
646 tr
->buffer_disabled
= 1;
647 /* Make the flag seen by readers */
652 * tracing_off - turn off tracing buffers
654 * This function stops the tracing buffers from recording data.
655 * It does not disable any overhead the tracers themselves may
656 * be causing. This function simply causes all recording to
657 * the ring buffers to fail.
659 void tracing_off(void)
661 tracer_tracing_off(&global_trace
);
663 EXPORT_SYMBOL_GPL(tracing_off
);
665 void disable_trace_on_warning(void)
667 if (__disable_trace_on_warning
)
672 * tracer_tracing_is_on - show real state of ring buffer enabled
673 * @tr : the trace array to know if ring buffer is enabled
675 * Shows real state of the ring buffer if it is enabled or not.
677 static int tracer_tracing_is_on(struct trace_array
*tr
)
679 if (tr
->trace_buffer
.buffer
)
680 return ring_buffer_record_is_on(tr
->trace_buffer
.buffer
);
681 return !tr
->buffer_disabled
;
685 * tracing_is_on - show state of ring buffers enabled
687 int tracing_is_on(void)
689 return tracer_tracing_is_on(&global_trace
);
691 EXPORT_SYMBOL_GPL(tracing_is_on
);
693 static int __init
set_buf_size(char *str
)
695 unsigned long buf_size
;
699 buf_size
= memparse(str
, &str
);
700 /* nr_entries can not be zero */
703 trace_buf_size
= buf_size
;
706 __setup("trace_buf_size=", set_buf_size
);
708 static int __init
set_tracing_thresh(char *str
)
710 unsigned long threshold
;
715 ret
= kstrtoul(str
, 0, &threshold
);
718 tracing_thresh
= threshold
* 1000;
721 __setup("tracing_thresh=", set_tracing_thresh
);
723 unsigned long nsecs_to_usecs(unsigned long nsecs
)
728 /* These must match the bit postions in trace_iterator_flags */
729 static const char *trace_options
[] = {
762 int in_ns
; /* is this clock in nanoseconds? */
764 { trace_clock_local
, "local", 1 },
765 { trace_clock_global
, "global", 1 },
766 { trace_clock_counter
, "counter", 0 },
767 { trace_clock_jiffies
, "uptime", 1 },
768 { trace_clock
, "perf", 1 },
773 * trace_parser_get_init - gets the buffer for trace parser
775 int trace_parser_get_init(struct trace_parser
*parser
, int size
)
777 memset(parser
, 0, sizeof(*parser
));
779 parser
->buffer
= kmalloc(size
, GFP_KERNEL
);
788 * trace_parser_put - frees the buffer for trace parser
790 void trace_parser_put(struct trace_parser
*parser
)
792 kfree(parser
->buffer
);
796 * trace_get_user - reads the user input string separated by space
797 * (matched by isspace(ch))
799 * For each string found the 'struct trace_parser' is updated,
800 * and the function returns.
802 * Returns number of bytes read.
804 * See kernel/trace/trace.h for 'struct trace_parser' details.
806 int trace_get_user(struct trace_parser
*parser
, const char __user
*ubuf
,
807 size_t cnt
, loff_t
*ppos
)
814 trace_parser_clear(parser
);
816 ret
= get_user(ch
, ubuf
++);
824 * The parser is not finished with the last write,
825 * continue reading the user input without skipping spaces.
828 /* skip white space */
829 while (cnt
&& isspace(ch
)) {
830 ret
= get_user(ch
, ubuf
++);
837 /* only spaces were written */
847 /* read the non-space input */
848 while (cnt
&& !isspace(ch
)) {
849 if (parser
->idx
< parser
->size
- 1)
850 parser
->buffer
[parser
->idx
++] = ch
;
855 ret
= get_user(ch
, ubuf
++);
862 /* We either got finished input or we have to wait for another call. */
864 parser
->buffer
[parser
->idx
] = 0;
865 parser
->cont
= false;
866 } else if (parser
->idx
< parser
->size
- 1) {
868 parser
->buffer
[parser
->idx
++] = ch
;
881 ssize_t
trace_seq_to_user(struct trace_seq
*s
, char __user
*ubuf
, size_t cnt
)
889 if (s
->len
<= s
->readpos
)
892 len
= s
->len
- s
->readpos
;
895 ret
= copy_to_user(ubuf
, s
->buffer
+ s
->readpos
, cnt
);
905 static ssize_t
trace_seq_to_buffer(struct trace_seq
*s
, void *buf
, size_t cnt
)
909 if (s
->len
<= s
->readpos
)
912 len
= s
->len
- s
->readpos
;
915 memcpy(buf
, s
->buffer
+ s
->readpos
, cnt
);
922 * ftrace_max_lock is used to protect the swapping of buffers
923 * when taking a max snapshot. The buffers themselves are
924 * protected by per_cpu spinlocks. But the action of the swap
925 * needs its own lock.
927 * This is defined as a arch_spinlock_t in order to help
928 * with performance when lockdep debugging is enabled.
930 * It is also used in other places outside the update_max_tr
931 * so it needs to be defined outside of the
932 * CONFIG_TRACER_MAX_TRACE.
934 static arch_spinlock_t ftrace_max_lock
=
935 (arch_spinlock_t
)__ARCH_SPIN_LOCK_UNLOCKED
;
937 unsigned long __read_mostly tracing_thresh
;
939 #ifdef CONFIG_TRACER_MAX_TRACE
940 unsigned long __read_mostly tracing_max_latency
;
943 * Copy the new maximum trace into the separate maximum-trace
944 * structure. (this way the maximum trace is permanently saved,
945 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
948 __update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
950 struct trace_buffer
*trace_buf
= &tr
->trace_buffer
;
951 struct trace_buffer
*max_buf
= &tr
->max_buffer
;
952 struct trace_array_cpu
*data
= per_cpu_ptr(trace_buf
->data
, cpu
);
953 struct trace_array_cpu
*max_data
= per_cpu_ptr(max_buf
->data
, cpu
);
956 max_buf
->time_start
= data
->preempt_timestamp
;
958 max_data
->saved_latency
= tracing_max_latency
;
959 max_data
->critical_start
= data
->critical_start
;
960 max_data
->critical_end
= data
->critical_end
;
962 memcpy(max_data
->comm
, tsk
->comm
, TASK_COMM_LEN
);
963 max_data
->pid
= tsk
->pid
;
965 * If tsk == current, then use current_uid(), as that does not use
966 * RCU. The irq tracer can be called out of RCU scope.
969 max_data
->uid
= current_uid();
971 max_data
->uid
= task_uid(tsk
);
973 max_data
->nice
= tsk
->static_prio
- 20 - MAX_RT_PRIO
;
974 max_data
->policy
= tsk
->policy
;
975 max_data
->rt_priority
= tsk
->rt_priority
;
977 /* record this tasks comm */
978 tracing_record_cmdline(tsk
);
982 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
984 * @tsk: the task with the latency
985 * @cpu: The cpu that initiated the trace.
987 * Flip the buffers between the @tr and the max_tr and record information
988 * about which task was the cause of this latency.
991 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
993 struct ring_buffer
*buf
;
998 WARN_ON_ONCE(!irqs_disabled());
1000 if (!tr
->allocated_snapshot
) {
1001 /* Only the nop tracer should hit this when disabling */
1002 WARN_ON_ONCE(tr
->current_trace
!= &nop_trace
);
1006 arch_spin_lock(&ftrace_max_lock
);
1008 buf
= tr
->trace_buffer
.buffer
;
1009 tr
->trace_buffer
.buffer
= tr
->max_buffer
.buffer
;
1010 tr
->max_buffer
.buffer
= buf
;
1012 __update_max_tr(tr
, tsk
, cpu
);
1013 arch_spin_unlock(&ftrace_max_lock
);
1017 * update_max_tr_single - only copy one trace over, and reset the rest
1019 * @tsk - task with the latency
1020 * @cpu - the cpu of the buffer to copy.
1022 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
1025 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
1032 WARN_ON_ONCE(!irqs_disabled());
1033 if (!tr
->allocated_snapshot
) {
1034 /* Only the nop tracer should hit this when disabling */
1035 WARN_ON_ONCE(tr
->current_trace
!= &nop_trace
);
1039 arch_spin_lock(&ftrace_max_lock
);
1041 ret
= ring_buffer_swap_cpu(tr
->max_buffer
.buffer
, tr
->trace_buffer
.buffer
, cpu
);
1043 if (ret
== -EBUSY
) {
1045 * We failed to swap the buffer due to a commit taking
1046 * place on this CPU. We fail to record, but we reset
1047 * the max trace buffer (no one writes directly to it)
1048 * and flag that it failed.
1050 trace_array_printk_buf(tr
->max_buffer
.buffer
, _THIS_IP_
,
1051 "Failed to swap buffers due to commit in progress\n");
1054 WARN_ON_ONCE(ret
&& ret
!= -EAGAIN
&& ret
!= -EBUSY
);
1056 __update_max_tr(tr
, tsk
, cpu
);
1057 arch_spin_unlock(&ftrace_max_lock
);
1059 #endif /* CONFIG_TRACER_MAX_TRACE */
1061 static void default_wait_pipe(struct trace_iterator
*iter
)
1063 /* Iterators are static, they should be filled or empty */
1064 if (trace_buffer_iter(iter
, iter
->cpu_file
))
1067 ring_buffer_wait(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
1070 #ifdef CONFIG_FTRACE_STARTUP_TEST
1071 static int run_tracer_selftest(struct tracer
*type
)
1073 struct trace_array
*tr
= &global_trace
;
1074 struct tracer
*saved_tracer
= tr
->current_trace
;
1077 if (!type
->selftest
|| tracing_selftest_disabled
)
1081 * Run a selftest on this tracer.
1082 * Here we reset the trace buffer, and set the current
1083 * tracer to be this tracer. The tracer can then run some
1084 * internal tracing to verify that everything is in order.
1085 * If we fail, we do not register this tracer.
1087 tracing_reset_online_cpus(&tr
->trace_buffer
);
1089 tr
->current_trace
= type
;
1091 #ifdef CONFIG_TRACER_MAX_TRACE
1092 if (type
->use_max_tr
) {
1093 /* If we expanded the buffers, make sure the max is expanded too */
1094 if (ring_buffer_expanded
)
1095 ring_buffer_resize(tr
->max_buffer
.buffer
, trace_buf_size
,
1096 RING_BUFFER_ALL_CPUS
);
1097 tr
->allocated_snapshot
= true;
1101 /* the test is responsible for initializing and enabling */
1102 pr_info("Testing tracer %s: ", type
->name
);
1103 ret
= type
->selftest(type
, tr
);
1104 /* the test is responsible for resetting too */
1105 tr
->current_trace
= saved_tracer
;
1107 printk(KERN_CONT
"FAILED!\n");
1108 /* Add the warning after printing 'FAILED' */
1112 /* Only reset on passing, to avoid touching corrupted buffers */
1113 tracing_reset_online_cpus(&tr
->trace_buffer
);
1115 #ifdef CONFIG_TRACER_MAX_TRACE
1116 if (type
->use_max_tr
) {
1117 tr
->allocated_snapshot
= false;
1119 /* Shrink the max buffer again */
1120 if (ring_buffer_expanded
)
1121 ring_buffer_resize(tr
->max_buffer
.buffer
, 1,
1122 RING_BUFFER_ALL_CPUS
);
1126 printk(KERN_CONT
"PASSED\n");
1130 static inline int run_tracer_selftest(struct tracer
*type
)
1134 #endif /* CONFIG_FTRACE_STARTUP_TEST */
1137 * register_tracer - register a tracer with the ftrace system.
1138 * @type - the plugin for the tracer
1140 * Register a new plugin tracer.
1142 int register_tracer(struct tracer
*type
)
1148 pr_info("Tracer must have a name\n");
1152 if (strlen(type
->name
) >= MAX_TRACER_SIZE
) {
1153 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE
);
1157 mutex_lock(&trace_types_lock
);
1159 tracing_selftest_running
= true;
1161 for (t
= trace_types
; t
; t
= t
->next
) {
1162 if (strcmp(type
->name
, t
->name
) == 0) {
1164 pr_info("Tracer %s already registered\n",
1171 if (!type
->set_flag
)
1172 type
->set_flag
= &dummy_set_flag
;
1174 type
->flags
= &dummy_tracer_flags
;
1176 if (!type
->flags
->opts
)
1177 type
->flags
->opts
= dummy_tracer_opt
;
1178 if (!type
->wait_pipe
)
1179 type
->wait_pipe
= default_wait_pipe
;
1181 ret
= run_tracer_selftest(type
);
1185 type
->next
= trace_types
;
1189 tracing_selftest_running
= false;
1190 mutex_unlock(&trace_types_lock
);
1192 if (ret
|| !default_bootup_tracer
)
1195 if (strncmp(default_bootup_tracer
, type
->name
, MAX_TRACER_SIZE
))
1198 printk(KERN_INFO
"Starting tracer '%s'\n", type
->name
);
1199 /* Do we want this tracer to start on bootup? */
1200 tracing_set_tracer(type
->name
);
1201 default_bootup_tracer
= NULL
;
1202 /* disable other selftests, since this will break it. */
1203 tracing_selftest_disabled
= true;
1204 #ifdef CONFIG_FTRACE_STARTUP_TEST
1205 printk(KERN_INFO
"Disabling FTRACE selftests due to running tracer '%s'\n",
1213 void tracing_reset(struct trace_buffer
*buf
, int cpu
)
1215 struct ring_buffer
*buffer
= buf
->buffer
;
1220 ring_buffer_record_disable(buffer
);
1222 /* Make sure all commits have finished */
1223 synchronize_sched();
1224 ring_buffer_reset_cpu(buffer
, cpu
);
1226 ring_buffer_record_enable(buffer
);
1229 void tracing_reset_online_cpus(struct trace_buffer
*buf
)
1231 struct ring_buffer
*buffer
= buf
->buffer
;
1237 ring_buffer_record_disable(buffer
);
1239 /* Make sure all commits have finished */
1240 synchronize_sched();
1242 buf
->time_start
= buffer_ftrace_now(buf
, buf
->cpu
);
1244 for_each_online_cpu(cpu
)
1245 ring_buffer_reset_cpu(buffer
, cpu
);
1247 ring_buffer_record_enable(buffer
);
1250 /* Must have trace_types_lock held */
1251 void tracing_reset_all_online_cpus(void)
1253 struct trace_array
*tr
;
1255 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
1256 tracing_reset_online_cpus(&tr
->trace_buffer
);
1257 #ifdef CONFIG_TRACER_MAX_TRACE
1258 tracing_reset_online_cpus(&tr
->max_buffer
);
1263 #define SAVED_CMDLINES 128
1264 #define NO_CMDLINE_MAP UINT_MAX
1265 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
1266 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
1267 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
1268 static int cmdline_idx
;
1269 static arch_spinlock_t trace_cmdline_lock
= __ARCH_SPIN_LOCK_UNLOCKED
;
1271 /* temporary disable recording */
1272 static atomic_t trace_record_cmdline_disabled __read_mostly
;
1274 static void trace_init_cmdlines(void)
1276 memset(&map_pid_to_cmdline
, NO_CMDLINE_MAP
, sizeof(map_pid_to_cmdline
));
1277 memset(&map_cmdline_to_pid
, NO_CMDLINE_MAP
, sizeof(map_cmdline_to_pid
));
1281 int is_tracing_stopped(void)
1283 return global_trace
.stop_count
;
1287 * tracing_start - quick start of the tracer
1289 * If tracing is enabled but was stopped by tracing_stop,
1290 * this will start the tracer back up.
1292 void tracing_start(void)
1294 struct ring_buffer
*buffer
;
1295 unsigned long flags
;
1297 if (tracing_disabled
)
1300 raw_spin_lock_irqsave(&global_trace
.start_lock
, flags
);
1301 if (--global_trace
.stop_count
) {
1302 if (global_trace
.stop_count
< 0) {
1303 /* Someone screwed up their debugging */
1305 global_trace
.stop_count
= 0;
1310 /* Prevent the buffers from switching */
1311 arch_spin_lock(&ftrace_max_lock
);
1313 buffer
= global_trace
.trace_buffer
.buffer
;
1315 ring_buffer_record_enable(buffer
);
1317 #ifdef CONFIG_TRACER_MAX_TRACE
1318 buffer
= global_trace
.max_buffer
.buffer
;
1320 ring_buffer_record_enable(buffer
);
1323 arch_spin_unlock(&ftrace_max_lock
);
1327 raw_spin_unlock_irqrestore(&global_trace
.start_lock
, flags
);
1330 static void tracing_start_tr(struct trace_array
*tr
)
1332 struct ring_buffer
*buffer
;
1333 unsigned long flags
;
1335 if (tracing_disabled
)
1338 /* If global, we need to also start the max tracer */
1339 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
1340 return tracing_start();
1342 raw_spin_lock_irqsave(&tr
->start_lock
, flags
);
1344 if (--tr
->stop_count
) {
1345 if (tr
->stop_count
< 0) {
1346 /* Someone screwed up their debugging */
1353 buffer
= tr
->trace_buffer
.buffer
;
1355 ring_buffer_record_enable(buffer
);
1358 raw_spin_unlock_irqrestore(&tr
->start_lock
, flags
);
1362 * tracing_stop - quick stop of the tracer
1364 * Light weight way to stop tracing. Use in conjunction with
1367 void tracing_stop(void)
1369 struct ring_buffer
*buffer
;
1370 unsigned long flags
;
1373 raw_spin_lock_irqsave(&global_trace
.start_lock
, flags
);
1374 if (global_trace
.stop_count
++)
1377 /* Prevent the buffers from switching */
1378 arch_spin_lock(&ftrace_max_lock
);
1380 buffer
= global_trace
.trace_buffer
.buffer
;
1382 ring_buffer_record_disable(buffer
);
1384 #ifdef CONFIG_TRACER_MAX_TRACE
1385 buffer
= global_trace
.max_buffer
.buffer
;
1387 ring_buffer_record_disable(buffer
);
1390 arch_spin_unlock(&ftrace_max_lock
);
1393 raw_spin_unlock_irqrestore(&global_trace
.start_lock
, flags
);
1396 static void tracing_stop_tr(struct trace_array
*tr
)
1398 struct ring_buffer
*buffer
;
1399 unsigned long flags
;
1401 /* If global, we need to also stop the max tracer */
1402 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
1403 return tracing_stop();
1405 raw_spin_lock_irqsave(&tr
->start_lock
, flags
);
1406 if (tr
->stop_count
++)
1409 buffer
= tr
->trace_buffer
.buffer
;
1411 ring_buffer_record_disable(buffer
);
1414 raw_spin_unlock_irqrestore(&tr
->start_lock
, flags
);
1417 void trace_stop_cmdline_recording(void);
1419 static void trace_save_cmdline(struct task_struct
*tsk
)
1423 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
1427 * It's not the end of the world if we don't get
1428 * the lock, but we also don't want to spin
1429 * nor do we want to disable interrupts,
1430 * so if we miss here, then better luck next time.
1432 if (!arch_spin_trylock(&trace_cmdline_lock
))
1435 idx
= map_pid_to_cmdline
[tsk
->pid
];
1436 if (idx
== NO_CMDLINE_MAP
) {
1437 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
1440 * Check whether the cmdline buffer at idx has a pid
1441 * mapped. We are going to overwrite that entry so we
1442 * need to clear the map_pid_to_cmdline. Otherwise we
1443 * would read the new comm for the old pid.
1445 pid
= map_cmdline_to_pid
[idx
];
1446 if (pid
!= NO_CMDLINE_MAP
)
1447 map_pid_to_cmdline
[pid
] = NO_CMDLINE_MAP
;
1449 map_cmdline_to_pid
[idx
] = tsk
->pid
;
1450 map_pid_to_cmdline
[tsk
->pid
] = idx
;
1455 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
1457 arch_spin_unlock(&trace_cmdline_lock
);
1460 void trace_find_cmdline(int pid
, char comm
[])
1465 strcpy(comm
, "<idle>");
1469 if (WARN_ON_ONCE(pid
< 0)) {
1470 strcpy(comm
, "<XXX>");
1474 if (pid
> PID_MAX_DEFAULT
) {
1475 strcpy(comm
, "<...>");
1480 arch_spin_lock(&trace_cmdline_lock
);
1481 map
= map_pid_to_cmdline
[pid
];
1482 if (map
!= NO_CMDLINE_MAP
)
1483 strcpy(comm
, saved_cmdlines
[map
]);
1485 strcpy(comm
, "<...>");
1487 arch_spin_unlock(&trace_cmdline_lock
);
1491 void tracing_record_cmdline(struct task_struct
*tsk
)
1493 if (atomic_read(&trace_record_cmdline_disabled
) || !tracing_is_on())
1496 if (!__this_cpu_read(trace_cmdline_save
))
1499 __this_cpu_write(trace_cmdline_save
, false);
1501 trace_save_cmdline(tsk
);
1505 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
,
1508 struct task_struct
*tsk
= current
;
1510 entry
->preempt_count
= pc
& 0xff;
1511 entry
->pid
= (tsk
) ? tsk
->pid
: 0;
1513 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1514 (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
1516 TRACE_FLAG_IRQS_NOSUPPORT
|
1518 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
1519 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
1520 (tif_need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0) |
1521 (test_preempt_need_resched() ? TRACE_FLAG_PREEMPT_RESCHED
: 0);
1523 EXPORT_SYMBOL_GPL(tracing_generic_entry_update
);
1525 struct ring_buffer_event
*
1526 trace_buffer_lock_reserve(struct ring_buffer
*buffer
,
1529 unsigned long flags
, int pc
)
1531 struct ring_buffer_event
*event
;
1533 event
= ring_buffer_lock_reserve(buffer
, len
);
1534 if (event
!= NULL
) {
1535 struct trace_entry
*ent
= ring_buffer_event_data(event
);
1537 tracing_generic_entry_update(ent
, flags
, pc
);
1545 __buffer_unlock_commit(struct ring_buffer
*buffer
, struct ring_buffer_event
*event
)
1547 __this_cpu_write(trace_cmdline_save
, true);
1548 ring_buffer_unlock_commit(buffer
, event
);
1552 __trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1553 struct ring_buffer_event
*event
,
1554 unsigned long flags
, int pc
)
1556 __buffer_unlock_commit(buffer
, event
);
1558 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1559 ftrace_trace_userstack(buffer
, flags
, pc
);
1562 void trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1563 struct ring_buffer_event
*event
,
1564 unsigned long flags
, int pc
)
1566 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
);
1568 EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit
);
1570 struct ring_buffer_event
*
1571 trace_event_buffer_lock_reserve(struct ring_buffer
**current_rb
,
1572 struct ftrace_event_file
*ftrace_file
,
1573 int type
, unsigned long len
,
1574 unsigned long flags
, int pc
)
1576 *current_rb
= ftrace_file
->tr
->trace_buffer
.buffer
;
1577 return trace_buffer_lock_reserve(*current_rb
,
1578 type
, len
, flags
, pc
);
1580 EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve
);
1582 struct ring_buffer_event
*
1583 trace_current_buffer_lock_reserve(struct ring_buffer
**current_rb
,
1584 int type
, unsigned long len
,
1585 unsigned long flags
, int pc
)
1587 *current_rb
= global_trace
.trace_buffer
.buffer
;
1588 return trace_buffer_lock_reserve(*current_rb
,
1589 type
, len
, flags
, pc
);
1591 EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve
);
1593 void trace_current_buffer_unlock_commit(struct ring_buffer
*buffer
,
1594 struct ring_buffer_event
*event
,
1595 unsigned long flags
, int pc
)
1597 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
);
1599 EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit
);
1601 void trace_buffer_unlock_commit_regs(struct ring_buffer
*buffer
,
1602 struct ring_buffer_event
*event
,
1603 unsigned long flags
, int pc
,
1604 struct pt_regs
*regs
)
1606 __buffer_unlock_commit(buffer
, event
);
1608 ftrace_trace_stack_regs(buffer
, flags
, 0, pc
, regs
);
1609 ftrace_trace_userstack(buffer
, flags
, pc
);
1611 EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit_regs
);
1613 void trace_current_buffer_discard_commit(struct ring_buffer
*buffer
,
1614 struct ring_buffer_event
*event
)
1616 ring_buffer_discard_commit(buffer
, event
);
1618 EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit
);
1621 trace_function(struct trace_array
*tr
,
1622 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
1625 struct ftrace_event_call
*call
= &event_function
;
1626 struct ring_buffer
*buffer
= tr
->trace_buffer
.buffer
;
1627 struct ring_buffer_event
*event
;
1628 struct ftrace_entry
*entry
;
1630 /* If we are reading the ring buffer, don't trace */
1631 if (unlikely(__this_cpu_read(ftrace_cpu_disabled
)))
1634 event
= trace_buffer_lock_reserve(buffer
, TRACE_FN
, sizeof(*entry
),
1638 entry
= ring_buffer_event_data(event
);
1640 entry
->parent_ip
= parent_ip
;
1642 if (!call_filter_check_discard(call
, entry
, buffer
, event
))
1643 __buffer_unlock_commit(buffer
, event
);
1646 #ifdef CONFIG_STACKTRACE
1648 #define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
1649 struct ftrace_stack
{
1650 unsigned long calls
[FTRACE_STACK_MAX_ENTRIES
];
1653 static DEFINE_PER_CPU(struct ftrace_stack
, ftrace_stack
);
1654 static DEFINE_PER_CPU(int, ftrace_stack_reserve
);
1656 static void __ftrace_trace_stack(struct ring_buffer
*buffer
,
1657 unsigned long flags
,
1658 int skip
, int pc
, struct pt_regs
*regs
)
1660 struct ftrace_event_call
*call
= &event_kernel_stack
;
1661 struct ring_buffer_event
*event
;
1662 struct stack_entry
*entry
;
1663 struct stack_trace trace
;
1665 int size
= FTRACE_STACK_ENTRIES
;
1667 trace
.nr_entries
= 0;
1671 * Since events can happen in NMIs there's no safe way to
1672 * use the per cpu ftrace_stacks. We reserve it and if an interrupt
1673 * or NMI comes in, it will just have to use the default
1674 * FTRACE_STACK_SIZE.
1676 preempt_disable_notrace();
1678 use_stack
= __this_cpu_inc_return(ftrace_stack_reserve
);
1680 * We don't need any atomic variables, just a barrier.
1681 * If an interrupt comes in, we don't care, because it would
1682 * have exited and put the counter back to what we want.
1683 * We just need a barrier to keep gcc from moving things
1687 if (use_stack
== 1) {
1688 trace
.entries
= &__get_cpu_var(ftrace_stack
).calls
[0];
1689 trace
.max_entries
= FTRACE_STACK_MAX_ENTRIES
;
1692 save_stack_trace_regs(regs
, &trace
);
1694 save_stack_trace(&trace
);
1696 if (trace
.nr_entries
> size
)
1697 size
= trace
.nr_entries
;
1699 /* From now on, use_stack is a boolean */
1702 size
*= sizeof(unsigned long);
1704 event
= trace_buffer_lock_reserve(buffer
, TRACE_STACK
,
1705 sizeof(*entry
) + size
, flags
, pc
);
1708 entry
= ring_buffer_event_data(event
);
1710 memset(&entry
->caller
, 0, size
);
1713 memcpy(&entry
->caller
, trace
.entries
,
1714 trace
.nr_entries
* sizeof(unsigned long));
1716 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1717 trace
.entries
= entry
->caller
;
1719 save_stack_trace_regs(regs
, &trace
);
1721 save_stack_trace(&trace
);
1724 entry
->size
= trace
.nr_entries
;
1726 if (!call_filter_check_discard(call
, entry
, buffer
, event
))
1727 __buffer_unlock_commit(buffer
, event
);
1730 /* Again, don't let gcc optimize things here */
1732 __this_cpu_dec(ftrace_stack_reserve
);
1733 preempt_enable_notrace();
1737 void ftrace_trace_stack_regs(struct ring_buffer
*buffer
, unsigned long flags
,
1738 int skip
, int pc
, struct pt_regs
*regs
)
1740 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1743 __ftrace_trace_stack(buffer
, flags
, skip
, pc
, regs
);
1746 void ftrace_trace_stack(struct ring_buffer
*buffer
, unsigned long flags
,
1749 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1752 __ftrace_trace_stack(buffer
, flags
, skip
, pc
, NULL
);
1755 void __trace_stack(struct trace_array
*tr
, unsigned long flags
, int skip
,
1758 __ftrace_trace_stack(tr
->trace_buffer
.buffer
, flags
, skip
, pc
, NULL
);
1762 * trace_dump_stack - record a stack back trace in the trace buffer
1763 * @skip: Number of functions to skip (helper handlers)
1765 void trace_dump_stack(int skip
)
1767 unsigned long flags
;
1769 if (tracing_disabled
|| tracing_selftest_running
)
1772 local_save_flags(flags
);
1775 * Skip 3 more, seems to get us at the caller of
1779 __ftrace_trace_stack(global_trace
.trace_buffer
.buffer
,
1780 flags
, skip
, preempt_count(), NULL
);
1783 static DEFINE_PER_CPU(int, user_stack_count
);
1786 ftrace_trace_userstack(struct ring_buffer
*buffer
, unsigned long flags
, int pc
)
1788 struct ftrace_event_call
*call
= &event_user_stack
;
1789 struct ring_buffer_event
*event
;
1790 struct userstack_entry
*entry
;
1791 struct stack_trace trace
;
1793 if (!(trace_flags
& TRACE_ITER_USERSTACKTRACE
))
1797 * NMIs can not handle page faults, even with fix ups.
1798 * The save user stack can (and often does) fault.
1800 if (unlikely(in_nmi()))
1804 * prevent recursion, since the user stack tracing may
1805 * trigger other kernel events.
1808 if (__this_cpu_read(user_stack_count
))
1811 __this_cpu_inc(user_stack_count
);
1813 event
= trace_buffer_lock_reserve(buffer
, TRACE_USER_STACK
,
1814 sizeof(*entry
), flags
, pc
);
1816 goto out_drop_count
;
1817 entry
= ring_buffer_event_data(event
);
1819 entry
->tgid
= current
->tgid
;
1820 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
1822 trace
.nr_entries
= 0;
1823 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1825 trace
.entries
= entry
->caller
;
1827 save_stack_trace_user(&trace
);
1828 if (!call_filter_check_discard(call
, entry
, buffer
, event
))
1829 __buffer_unlock_commit(buffer
, event
);
1832 __this_cpu_dec(user_stack_count
);
1838 static void __trace_userstack(struct trace_array
*tr
, unsigned long flags
)
1840 ftrace_trace_userstack(tr
, flags
, preempt_count());
1844 #endif /* CONFIG_STACKTRACE */
1846 /* created for use with alloc_percpu */
1847 struct trace_buffer_struct
{
1848 char buffer
[TRACE_BUF_SIZE
];
1851 static struct trace_buffer_struct
*trace_percpu_buffer
;
1852 static struct trace_buffer_struct
*trace_percpu_sirq_buffer
;
1853 static struct trace_buffer_struct
*trace_percpu_irq_buffer
;
1854 static struct trace_buffer_struct
*trace_percpu_nmi_buffer
;
1857 * The buffer used is dependent on the context. There is a per cpu
1858 * buffer for normal context, softirq contex, hard irq context and
1859 * for NMI context. Thise allows for lockless recording.
1861 * Note, if the buffers failed to be allocated, then this returns NULL
1863 static char *get_trace_buf(void)
1865 struct trace_buffer_struct
*percpu_buffer
;
1868 * If we have allocated per cpu buffers, then we do not
1869 * need to do any locking.
1872 percpu_buffer
= trace_percpu_nmi_buffer
;
1874 percpu_buffer
= trace_percpu_irq_buffer
;
1875 else if (in_softirq())
1876 percpu_buffer
= trace_percpu_sirq_buffer
;
1878 percpu_buffer
= trace_percpu_buffer
;
1883 return this_cpu_ptr(&percpu_buffer
->buffer
[0]);
1886 static int alloc_percpu_trace_buffer(void)
1888 struct trace_buffer_struct
*buffers
;
1889 struct trace_buffer_struct
*sirq_buffers
;
1890 struct trace_buffer_struct
*irq_buffers
;
1891 struct trace_buffer_struct
*nmi_buffers
;
1893 buffers
= alloc_percpu(struct trace_buffer_struct
);
1897 sirq_buffers
= alloc_percpu(struct trace_buffer_struct
);
1901 irq_buffers
= alloc_percpu(struct trace_buffer_struct
);
1905 nmi_buffers
= alloc_percpu(struct trace_buffer_struct
);
1909 trace_percpu_buffer
= buffers
;
1910 trace_percpu_sirq_buffer
= sirq_buffers
;
1911 trace_percpu_irq_buffer
= irq_buffers
;
1912 trace_percpu_nmi_buffer
= nmi_buffers
;
1917 free_percpu(irq_buffers
);
1919 free_percpu(sirq_buffers
);
1921 free_percpu(buffers
);
1923 WARN(1, "Could not allocate percpu trace_printk buffer");
1927 static int buffers_allocated
;
1929 void trace_printk_init_buffers(void)
1931 if (buffers_allocated
)
1934 if (alloc_percpu_trace_buffer())
1937 pr_info("ftrace: Allocated trace_printk buffers\n");
1939 /* Expand the buffers to set size */
1940 tracing_update_buffers();
1942 buffers_allocated
= 1;
1945 * trace_printk_init_buffers() can be called by modules.
1946 * If that happens, then we need to start cmdline recording
1947 * directly here. If the global_trace.buffer is already
1948 * allocated here, then this was called by module code.
1950 if (global_trace
.trace_buffer
.buffer
)
1951 tracing_start_cmdline_record();
1954 void trace_printk_start_comm(void)
1956 /* Start tracing comms if trace printk is set */
1957 if (!buffers_allocated
)
1959 tracing_start_cmdline_record();
1962 static void trace_printk_start_stop_comm(int enabled
)
1964 if (!buffers_allocated
)
1968 tracing_start_cmdline_record();
1970 tracing_stop_cmdline_record();
1974 * trace_vbprintk - write binary msg to tracing buffer
1977 int trace_vbprintk(unsigned long ip
, const char *fmt
, va_list args
)
1979 struct ftrace_event_call
*call
= &event_bprint
;
1980 struct ring_buffer_event
*event
;
1981 struct ring_buffer
*buffer
;
1982 struct trace_array
*tr
= &global_trace
;
1983 struct bprint_entry
*entry
;
1984 unsigned long flags
;
1986 int len
= 0, size
, pc
;
1988 if (unlikely(tracing_selftest_running
|| tracing_disabled
))
1991 /* Don't pollute graph traces with trace_vprintk internals */
1992 pause_graph_tracing();
1994 pc
= preempt_count();
1995 preempt_disable_notrace();
1997 tbuffer
= get_trace_buf();
2003 len
= vbin_printf((u32
*)tbuffer
, TRACE_BUF_SIZE
/sizeof(int), fmt
, args
);
2005 if (len
> TRACE_BUF_SIZE
/sizeof(int) || len
< 0)
2008 local_save_flags(flags
);
2009 size
= sizeof(*entry
) + sizeof(u32
) * len
;
2010 buffer
= tr
->trace_buffer
.buffer
;
2011 event
= trace_buffer_lock_reserve(buffer
, TRACE_BPRINT
, size
,
2015 entry
= ring_buffer_event_data(event
);
2019 memcpy(entry
->buf
, tbuffer
, sizeof(u32
) * len
);
2020 if (!call_filter_check_discard(call
, entry
, buffer
, event
)) {
2021 __buffer_unlock_commit(buffer
, event
);
2022 ftrace_trace_stack(buffer
, flags
, 6, pc
);
2026 preempt_enable_notrace();
2027 unpause_graph_tracing();
2031 EXPORT_SYMBOL_GPL(trace_vbprintk
);
2034 __trace_array_vprintk(struct ring_buffer
*buffer
,
2035 unsigned long ip
, const char *fmt
, va_list args
)
2037 struct ftrace_event_call
*call
= &event_print
;
2038 struct ring_buffer_event
*event
;
2039 int len
= 0, size
, pc
;
2040 struct print_entry
*entry
;
2041 unsigned long flags
;
2044 if (tracing_disabled
|| tracing_selftest_running
)
2047 /* Don't pollute graph traces with trace_vprintk internals */
2048 pause_graph_tracing();
2050 pc
= preempt_count();
2051 preempt_disable_notrace();
2054 tbuffer
= get_trace_buf();
2060 len
= vsnprintf(tbuffer
, TRACE_BUF_SIZE
, fmt
, args
);
2061 if (len
> TRACE_BUF_SIZE
)
2064 local_save_flags(flags
);
2065 size
= sizeof(*entry
) + len
+ 1;
2066 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, size
,
2070 entry
= ring_buffer_event_data(event
);
2073 memcpy(&entry
->buf
, tbuffer
, len
);
2074 entry
->buf
[len
] = '\0';
2075 if (!call_filter_check_discard(call
, entry
, buffer
, event
)) {
2076 __buffer_unlock_commit(buffer
, event
);
2077 ftrace_trace_stack(buffer
, flags
, 6, pc
);
2080 preempt_enable_notrace();
2081 unpause_graph_tracing();
2086 int trace_array_vprintk(struct trace_array
*tr
,
2087 unsigned long ip
, const char *fmt
, va_list args
)
2089 return __trace_array_vprintk(tr
->trace_buffer
.buffer
, ip
, fmt
, args
);
2092 int trace_array_printk(struct trace_array
*tr
,
2093 unsigned long ip
, const char *fmt
, ...)
2098 if (!(trace_flags
& TRACE_ITER_PRINTK
))
2102 ret
= trace_array_vprintk(tr
, ip
, fmt
, ap
);
2107 int trace_array_printk_buf(struct ring_buffer
*buffer
,
2108 unsigned long ip
, const char *fmt
, ...)
2113 if (!(trace_flags
& TRACE_ITER_PRINTK
))
2117 ret
= __trace_array_vprintk(buffer
, ip
, fmt
, ap
);
2122 int trace_vprintk(unsigned long ip
, const char *fmt
, va_list args
)
2124 return trace_array_vprintk(&global_trace
, ip
, fmt
, args
);
2126 EXPORT_SYMBOL_GPL(trace_vprintk
);
2128 static void trace_iterator_increment(struct trace_iterator
*iter
)
2130 struct ring_buffer_iter
*buf_iter
= trace_buffer_iter(iter
, iter
->cpu
);
2134 ring_buffer_read(buf_iter
, NULL
);
2137 static struct trace_entry
*
2138 peek_next_entry(struct trace_iterator
*iter
, int cpu
, u64
*ts
,
2139 unsigned long *lost_events
)
2141 struct ring_buffer_event
*event
;
2142 struct ring_buffer_iter
*buf_iter
= trace_buffer_iter(iter
, cpu
);
2145 event
= ring_buffer_iter_peek(buf_iter
, ts
);
2147 event
= ring_buffer_peek(iter
->trace_buffer
->buffer
, cpu
, ts
,
2151 iter
->ent_size
= ring_buffer_event_length(event
);
2152 return ring_buffer_event_data(event
);
2158 static struct trace_entry
*
2159 __find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
,
2160 unsigned long *missing_events
, u64
*ent_ts
)
2162 struct ring_buffer
*buffer
= iter
->trace_buffer
->buffer
;
2163 struct trace_entry
*ent
, *next
= NULL
;
2164 unsigned long lost_events
= 0, next_lost
= 0;
2165 int cpu_file
= iter
->cpu_file
;
2166 u64 next_ts
= 0, ts
;
2172 * If we are in a per_cpu trace file, don't bother by iterating over
2173 * all cpu and peek directly.
2175 if (cpu_file
> RING_BUFFER_ALL_CPUS
) {
2176 if (ring_buffer_empty_cpu(buffer
, cpu_file
))
2178 ent
= peek_next_entry(iter
, cpu_file
, ent_ts
, missing_events
);
2180 *ent_cpu
= cpu_file
;
2185 for_each_tracing_cpu(cpu
) {
2187 if (ring_buffer_empty_cpu(buffer
, cpu
))
2190 ent
= peek_next_entry(iter
, cpu
, &ts
, &lost_events
);
2193 * Pick the entry with the smallest timestamp:
2195 if (ent
&& (!next
|| ts
< next_ts
)) {
2199 next_lost
= lost_events
;
2200 next_size
= iter
->ent_size
;
2204 iter
->ent_size
= next_size
;
2207 *ent_cpu
= next_cpu
;
2213 *missing_events
= next_lost
;
2218 /* Find the next real entry, without updating the iterator itself */
2219 struct trace_entry
*trace_find_next_entry(struct trace_iterator
*iter
,
2220 int *ent_cpu
, u64
*ent_ts
)
2222 return __find_next_entry(iter
, ent_cpu
, NULL
, ent_ts
);
2225 /* Find the next real entry, and increment the iterator to the next entry */
2226 void *trace_find_next_entry_inc(struct trace_iterator
*iter
)
2228 iter
->ent
= __find_next_entry(iter
, &iter
->cpu
,
2229 &iter
->lost_events
, &iter
->ts
);
2232 trace_iterator_increment(iter
);
2234 return iter
->ent
? iter
: NULL
;
2237 static void trace_consume(struct trace_iterator
*iter
)
2239 ring_buffer_consume(iter
->trace_buffer
->buffer
, iter
->cpu
, &iter
->ts
,
2240 &iter
->lost_events
);
2243 static void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
2245 struct trace_iterator
*iter
= m
->private;
2249 WARN_ON_ONCE(iter
->leftover
);
2253 /* can't go backwards */
2258 ent
= trace_find_next_entry_inc(iter
);
2262 while (ent
&& iter
->idx
< i
)
2263 ent
= trace_find_next_entry_inc(iter
);
2270 void tracing_iter_reset(struct trace_iterator
*iter
, int cpu
)
2272 struct ring_buffer_event
*event
;
2273 struct ring_buffer_iter
*buf_iter
;
2274 unsigned long entries
= 0;
2277 per_cpu_ptr(iter
->trace_buffer
->data
, cpu
)->skipped_entries
= 0;
2279 buf_iter
= trace_buffer_iter(iter
, cpu
);
2283 ring_buffer_iter_reset(buf_iter
);
2286 * We could have the case with the max latency tracers
2287 * that a reset never took place on a cpu. This is evident
2288 * by the timestamp being before the start of the buffer.
2290 while ((event
= ring_buffer_iter_peek(buf_iter
, &ts
))) {
2291 if (ts
>= iter
->trace_buffer
->time_start
)
2294 ring_buffer_read(buf_iter
, NULL
);
2297 per_cpu_ptr(iter
->trace_buffer
->data
, cpu
)->skipped_entries
= entries
;
2301 * The current tracer is copied to avoid a global locking
2304 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
2306 struct trace_iterator
*iter
= m
->private;
2307 struct trace_array
*tr
= iter
->tr
;
2308 int cpu_file
= iter
->cpu_file
;
2314 * copy the tracer to avoid using a global lock all around.
2315 * iter->trace is a copy of current_trace, the pointer to the
2316 * name may be used instead of a strcmp(), as iter->trace->name
2317 * will point to the same string as current_trace->name.
2319 mutex_lock(&trace_types_lock
);
2320 if (unlikely(tr
->current_trace
&& iter
->trace
->name
!= tr
->current_trace
->name
))
2321 *iter
->trace
= *tr
->current_trace
;
2322 mutex_unlock(&trace_types_lock
);
2324 #ifdef CONFIG_TRACER_MAX_TRACE
2325 if (iter
->snapshot
&& iter
->trace
->use_max_tr
)
2326 return ERR_PTR(-EBUSY
);
2329 if (!iter
->snapshot
)
2330 atomic_inc(&trace_record_cmdline_disabled
);
2332 if (*pos
!= iter
->pos
) {
2337 if (cpu_file
== RING_BUFFER_ALL_CPUS
) {
2338 for_each_tracing_cpu(cpu
)
2339 tracing_iter_reset(iter
, cpu
);
2341 tracing_iter_reset(iter
, cpu_file
);
2344 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
2349 * If we overflowed the seq_file before, then we want
2350 * to just reuse the trace_seq buffer again.
2356 p
= s_next(m
, p
, &l
);
2360 trace_event_read_lock();
2361 trace_access_lock(cpu_file
);
2365 static void s_stop(struct seq_file
*m
, void *p
)
2367 struct trace_iterator
*iter
= m
->private;
2369 #ifdef CONFIG_TRACER_MAX_TRACE
2370 if (iter
->snapshot
&& iter
->trace
->use_max_tr
)
2374 if (!iter
->snapshot
)
2375 atomic_dec(&trace_record_cmdline_disabled
);
2377 trace_access_unlock(iter
->cpu_file
);
2378 trace_event_read_unlock();
2382 get_total_entries(struct trace_buffer
*buf
,
2383 unsigned long *total
, unsigned long *entries
)
2385 unsigned long count
;
2391 for_each_tracing_cpu(cpu
) {
2392 count
= ring_buffer_entries_cpu(buf
->buffer
, cpu
);
2394 * If this buffer has skipped entries, then we hold all
2395 * entries for the trace and we need to ignore the
2396 * ones before the time stamp.
2398 if (per_cpu_ptr(buf
->data
, cpu
)->skipped_entries
) {
2399 count
-= per_cpu_ptr(buf
->data
, cpu
)->skipped_entries
;
2400 /* total is the same as the entries */
2404 ring_buffer_overrun_cpu(buf
->buffer
, cpu
);
2409 static void print_lat_help_header(struct seq_file
*m
)
2411 seq_puts(m
, "# _------=> CPU# \n");
2412 seq_puts(m
, "# / _-----=> irqs-off \n");
2413 seq_puts(m
, "# | / _----=> need-resched \n");
2414 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
2415 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
2416 seq_puts(m
, "# |||| / delay \n");
2417 seq_puts(m
, "# cmd pid ||||| time | caller \n");
2418 seq_puts(m
, "# \\ / ||||| \\ | / \n");
2421 static void print_event_info(struct trace_buffer
*buf
, struct seq_file
*m
)
2423 unsigned long total
;
2424 unsigned long entries
;
2426 get_total_entries(buf
, &total
, &entries
);
2427 seq_printf(m
, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
2428 entries
, total
, num_online_cpus());
2432 static void print_func_help_header(struct trace_buffer
*buf
, struct seq_file
*m
)
2434 print_event_info(buf
, m
);
2435 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
2436 seq_puts(m
, "# | | | | |\n");
2439 static void print_func_help_header_irq(struct trace_buffer
*buf
, struct seq_file
*m
)
2441 print_event_info(buf
, m
);
2442 seq_puts(m
, "# _-----=> irqs-off\n");
2443 seq_puts(m
, "# / _----=> need-resched\n");
2444 seq_puts(m
, "# | / _---=> hardirq/softirq\n");
2445 seq_puts(m
, "# || / _--=> preempt-depth\n");
2446 seq_puts(m
, "# ||| / delay\n");
2447 seq_puts(m
, "# TASK-PID CPU# |||| TIMESTAMP FUNCTION\n");
2448 seq_puts(m
, "# | | | |||| | |\n");
2452 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
2454 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
2455 struct trace_buffer
*buf
= iter
->trace_buffer
;
2456 struct trace_array_cpu
*data
= per_cpu_ptr(buf
->data
, buf
->cpu
);
2457 struct tracer
*type
= iter
->trace
;
2458 unsigned long entries
;
2459 unsigned long total
;
2460 const char *name
= "preemption";
2464 get_total_entries(buf
, &total
, &entries
);
2466 seq_printf(m
, "# %s latency trace v1.1.5 on %s\n",
2468 seq_puts(m
, "# -----------------------------------"
2469 "---------------------------------\n");
2470 seq_printf(m
, "# latency: %lu us, #%lu/%lu, CPU#%d |"
2471 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
2472 nsecs_to_usecs(data
->saved_latency
),
2476 #if defined(CONFIG_PREEMPT_NONE)
2478 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
2480 #elif defined(CONFIG_PREEMPT)
2485 /* These are reserved for later use */
2488 seq_printf(m
, " #P:%d)\n", num_online_cpus());
2492 seq_puts(m
, "# -----------------\n");
2493 seq_printf(m
, "# | task: %.16s-%d "
2494 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
2495 data
->comm
, data
->pid
,
2496 from_kuid_munged(seq_user_ns(m
), data
->uid
), data
->nice
,
2497 data
->policy
, data
->rt_priority
);
2498 seq_puts(m
, "# -----------------\n");
2500 if (data
->critical_start
) {
2501 seq_puts(m
, "# => started at: ");
2502 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
2503 trace_print_seq(m
, &iter
->seq
);
2504 seq_puts(m
, "\n# => ended at: ");
2505 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
2506 trace_print_seq(m
, &iter
->seq
);
2507 seq_puts(m
, "\n#\n");
2513 static void test_cpu_buff_start(struct trace_iterator
*iter
)
2515 struct trace_seq
*s
= &iter
->seq
;
2517 if (!(trace_flags
& TRACE_ITER_ANNOTATE
))
2520 if (!(iter
->iter_flags
& TRACE_FILE_ANNOTATE
))
2523 if (cpumask_test_cpu(iter
->cpu
, iter
->started
))
2526 if (per_cpu_ptr(iter
->trace_buffer
->data
, iter
->cpu
)->skipped_entries
)
2529 cpumask_set_cpu(iter
->cpu
, iter
->started
);
2531 /* Don't print started cpu buffer for the first entry of the trace */
2533 trace_seq_printf(s
, "##### CPU %u buffer started ####\n",
2537 static enum print_line_t
print_trace_fmt(struct trace_iterator
*iter
)
2539 struct trace_seq
*s
= &iter
->seq
;
2540 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
2541 struct trace_entry
*entry
;
2542 struct trace_event
*event
;
2546 test_cpu_buff_start(iter
);
2548 event
= ftrace_find_event(entry
->type
);
2550 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2551 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
2552 if (!trace_print_lat_context(iter
))
2555 if (!trace_print_context(iter
))
2561 return event
->funcs
->trace(iter
, sym_flags
, event
);
2563 if (!trace_seq_printf(s
, "Unknown type %d\n", entry
->type
))
2566 return TRACE_TYPE_HANDLED
;
2568 return TRACE_TYPE_PARTIAL_LINE
;
2571 static enum print_line_t
print_raw_fmt(struct trace_iterator
*iter
)
2573 struct trace_seq
*s
= &iter
->seq
;
2574 struct trace_entry
*entry
;
2575 struct trace_event
*event
;
2579 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2580 if (!trace_seq_printf(s
, "%d %d %llu ",
2581 entry
->pid
, iter
->cpu
, iter
->ts
))
2585 event
= ftrace_find_event(entry
->type
);
2587 return event
->funcs
->raw(iter
, 0, event
);
2589 if (!trace_seq_printf(s
, "%d ?\n", entry
->type
))
2592 return TRACE_TYPE_HANDLED
;
2594 return TRACE_TYPE_PARTIAL_LINE
;
2597 static enum print_line_t
print_hex_fmt(struct trace_iterator
*iter
)
2599 struct trace_seq
*s
= &iter
->seq
;
2600 unsigned char newline
= '\n';
2601 struct trace_entry
*entry
;
2602 struct trace_event
*event
;
2606 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2607 SEQ_PUT_HEX_FIELD_RET(s
, entry
->pid
);
2608 SEQ_PUT_HEX_FIELD_RET(s
, iter
->cpu
);
2609 SEQ_PUT_HEX_FIELD_RET(s
, iter
->ts
);
2612 event
= ftrace_find_event(entry
->type
);
2614 enum print_line_t ret
= event
->funcs
->hex(iter
, 0, event
);
2615 if (ret
!= TRACE_TYPE_HANDLED
)
2619 SEQ_PUT_FIELD_RET(s
, newline
);
2621 return TRACE_TYPE_HANDLED
;
2624 static enum print_line_t
print_bin_fmt(struct trace_iterator
*iter
)
2626 struct trace_seq
*s
= &iter
->seq
;
2627 struct trace_entry
*entry
;
2628 struct trace_event
*event
;
2632 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2633 SEQ_PUT_FIELD_RET(s
, entry
->pid
);
2634 SEQ_PUT_FIELD_RET(s
, iter
->cpu
);
2635 SEQ_PUT_FIELD_RET(s
, iter
->ts
);
2638 event
= ftrace_find_event(entry
->type
);
2639 return event
? event
->funcs
->binary(iter
, 0, event
) :
2643 int trace_empty(struct trace_iterator
*iter
)
2645 struct ring_buffer_iter
*buf_iter
;
2648 /* If we are looking at one CPU buffer, only check that one */
2649 if (iter
->cpu_file
!= RING_BUFFER_ALL_CPUS
) {
2650 cpu
= iter
->cpu_file
;
2651 buf_iter
= trace_buffer_iter(iter
, cpu
);
2653 if (!ring_buffer_iter_empty(buf_iter
))
2656 if (!ring_buffer_empty_cpu(iter
->trace_buffer
->buffer
, cpu
))
2662 for_each_tracing_cpu(cpu
) {
2663 buf_iter
= trace_buffer_iter(iter
, cpu
);
2665 if (!ring_buffer_iter_empty(buf_iter
))
2668 if (!ring_buffer_empty_cpu(iter
->trace_buffer
->buffer
, cpu
))
2676 /* Called with trace_event_read_lock() held. */
2677 enum print_line_t
print_trace_line(struct trace_iterator
*iter
)
2679 enum print_line_t ret
;
2681 if (iter
->lost_events
&&
2682 !trace_seq_printf(&iter
->seq
, "CPU:%d [LOST %lu EVENTS]\n",
2683 iter
->cpu
, iter
->lost_events
))
2684 return TRACE_TYPE_PARTIAL_LINE
;
2686 if (iter
->trace
&& iter
->trace
->print_line
) {
2687 ret
= iter
->trace
->print_line(iter
);
2688 if (ret
!= TRACE_TYPE_UNHANDLED
)
2692 if (iter
->ent
->type
== TRACE_BPUTS
&&
2693 trace_flags
& TRACE_ITER_PRINTK
&&
2694 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2695 return trace_print_bputs_msg_only(iter
);
2697 if (iter
->ent
->type
== TRACE_BPRINT
&&
2698 trace_flags
& TRACE_ITER_PRINTK
&&
2699 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2700 return trace_print_bprintk_msg_only(iter
);
2702 if (iter
->ent
->type
== TRACE_PRINT
&&
2703 trace_flags
& TRACE_ITER_PRINTK
&&
2704 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2705 return trace_print_printk_msg_only(iter
);
2707 if (trace_flags
& TRACE_ITER_BIN
)
2708 return print_bin_fmt(iter
);
2710 if (trace_flags
& TRACE_ITER_HEX
)
2711 return print_hex_fmt(iter
);
2713 if (trace_flags
& TRACE_ITER_RAW
)
2714 return print_raw_fmt(iter
);
2716 return print_trace_fmt(iter
);
2719 void trace_latency_header(struct seq_file
*m
)
2721 struct trace_iterator
*iter
= m
->private;
2723 /* print nothing if the buffers are empty */
2724 if (trace_empty(iter
))
2727 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
)
2728 print_trace_header(m
, iter
);
2730 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2731 print_lat_help_header(m
);
2734 void trace_default_header(struct seq_file
*m
)
2736 struct trace_iterator
*iter
= m
->private;
2738 if (!(trace_flags
& TRACE_ITER_CONTEXT_INFO
))
2741 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
2742 /* print nothing if the buffers are empty */
2743 if (trace_empty(iter
))
2745 print_trace_header(m
, iter
);
2746 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2747 print_lat_help_header(m
);
2749 if (!(trace_flags
& TRACE_ITER_VERBOSE
)) {
2750 if (trace_flags
& TRACE_ITER_IRQ_INFO
)
2751 print_func_help_header_irq(iter
->trace_buffer
, m
);
2753 print_func_help_header(iter
->trace_buffer
, m
);
2758 static void test_ftrace_alive(struct seq_file
*m
)
2760 if (!ftrace_is_dead())
2762 seq_printf(m
, "# WARNING: FUNCTION TRACING IS CORRUPTED\n");
2763 seq_printf(m
, "# MAY BE MISSING FUNCTION EVENTS\n");
2766 #ifdef CONFIG_TRACER_MAX_TRACE
2767 static void show_snapshot_main_help(struct seq_file
*m
)
2769 seq_printf(m
, "# echo 0 > snapshot : Clears and frees snapshot buffer\n");
2770 seq_printf(m
, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
2771 seq_printf(m
, "# Takes a snapshot of the main buffer.\n");
2772 seq_printf(m
, "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n");
2773 seq_printf(m
, "# (Doesn't have to be '2' works with any number that\n");
2774 seq_printf(m
, "# is not a '0' or '1')\n");
2777 static void show_snapshot_percpu_help(struct seq_file
*m
)
2779 seq_printf(m
, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
2780 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
2781 seq_printf(m
, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
2782 seq_printf(m
, "# Takes a snapshot of the main buffer for this cpu.\n");
2784 seq_printf(m
, "# echo 1 > snapshot : Not supported with this kernel.\n");
2785 seq_printf(m
, "# Must use main snapshot file to allocate.\n");
2787 seq_printf(m
, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n");
2788 seq_printf(m
, "# (Doesn't have to be '2' works with any number that\n");
2789 seq_printf(m
, "# is not a '0' or '1')\n");
2792 static void print_snapshot_help(struct seq_file
*m
, struct trace_iterator
*iter
)
2794 if (iter
->tr
->allocated_snapshot
)
2795 seq_printf(m
, "#\n# * Snapshot is allocated *\n#\n");
2797 seq_printf(m
, "#\n# * Snapshot is freed *\n#\n");
2799 seq_printf(m
, "# Snapshot commands:\n");
2800 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
)
2801 show_snapshot_main_help(m
);
2803 show_snapshot_percpu_help(m
);
2806 /* Should never be called */
2807 static inline void print_snapshot_help(struct seq_file
*m
, struct trace_iterator
*iter
) { }
2810 static int s_show(struct seq_file
*m
, void *v
)
2812 struct trace_iterator
*iter
= v
;
2815 if (iter
->ent
== NULL
) {
2817 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
2819 test_ftrace_alive(m
);
2821 if (iter
->snapshot
&& trace_empty(iter
))
2822 print_snapshot_help(m
, iter
);
2823 else if (iter
->trace
&& iter
->trace
->print_header
)
2824 iter
->trace
->print_header(m
);
2826 trace_default_header(m
);
2828 } else if (iter
->leftover
) {
2830 * If we filled the seq_file buffer earlier, we
2831 * want to just show it now.
2833 ret
= trace_print_seq(m
, &iter
->seq
);
2835 /* ret should this time be zero, but you never know */
2836 iter
->leftover
= ret
;
2839 print_trace_line(iter
);
2840 ret
= trace_print_seq(m
, &iter
->seq
);
2842 * If we overflow the seq_file buffer, then it will
2843 * ask us for this data again at start up.
2845 * ret is 0 if seq_file write succeeded.
2848 iter
->leftover
= ret
;
2855 * Should be used after trace_array_get(), trace_types_lock
2856 * ensures that i_cdev was already initialized.
2858 static inline int tracing_get_cpu(struct inode
*inode
)
2860 if (inode
->i_cdev
) /* See trace_create_cpu_file() */
2861 return (long)inode
->i_cdev
- 1;
2862 return RING_BUFFER_ALL_CPUS
;
2865 static const struct seq_operations tracer_seq_ops
= {
2872 static struct trace_iterator
*
2873 __tracing_open(struct inode
*inode
, struct file
*file
, bool snapshot
)
2875 struct trace_array
*tr
= inode
->i_private
;
2876 struct trace_iterator
*iter
;
2879 if (tracing_disabled
)
2880 return ERR_PTR(-ENODEV
);
2882 iter
= __seq_open_private(file
, &tracer_seq_ops
, sizeof(*iter
));
2884 return ERR_PTR(-ENOMEM
);
2886 iter
->buffer_iter
= kzalloc(sizeof(*iter
->buffer_iter
) * num_possible_cpus(),
2888 if (!iter
->buffer_iter
)
2892 * We make a copy of the current tracer to avoid concurrent
2893 * changes on it while we are reading.
2895 mutex_lock(&trace_types_lock
);
2896 iter
->trace
= kzalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
2900 *iter
->trace
= *tr
->current_trace
;
2902 if (!zalloc_cpumask_var(&iter
->started
, GFP_KERNEL
))
2907 #ifdef CONFIG_TRACER_MAX_TRACE
2908 /* Currently only the top directory has a snapshot */
2909 if (tr
->current_trace
->print_max
|| snapshot
)
2910 iter
->trace_buffer
= &tr
->max_buffer
;
2913 iter
->trace_buffer
= &tr
->trace_buffer
;
2914 iter
->snapshot
= snapshot
;
2916 iter
->cpu_file
= tracing_get_cpu(inode
);
2917 mutex_init(&iter
->mutex
);
2919 /* Notify the tracer early; before we stop tracing. */
2920 if (iter
->trace
&& iter
->trace
->open
)
2921 iter
->trace
->open(iter
);
2923 /* Annotate start of buffers if we had overruns */
2924 if (ring_buffer_overruns(iter
->trace_buffer
->buffer
))
2925 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
2927 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
2928 if (trace_clocks
[tr
->clock_id
].in_ns
)
2929 iter
->iter_flags
|= TRACE_FILE_TIME_IN_NS
;
2931 /* stop the trace while dumping if we are not opening "snapshot" */
2932 if (!iter
->snapshot
)
2933 tracing_stop_tr(tr
);
2935 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
) {
2936 for_each_tracing_cpu(cpu
) {
2937 iter
->buffer_iter
[cpu
] =
2938 ring_buffer_read_prepare(iter
->trace_buffer
->buffer
, cpu
);
2940 ring_buffer_read_prepare_sync();
2941 for_each_tracing_cpu(cpu
) {
2942 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2943 tracing_iter_reset(iter
, cpu
);
2946 cpu
= iter
->cpu_file
;
2947 iter
->buffer_iter
[cpu
] =
2948 ring_buffer_read_prepare(iter
->trace_buffer
->buffer
, cpu
);
2949 ring_buffer_read_prepare_sync();
2950 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2951 tracing_iter_reset(iter
, cpu
);
2954 mutex_unlock(&trace_types_lock
);
2959 mutex_unlock(&trace_types_lock
);
2961 kfree(iter
->buffer_iter
);
2963 seq_release_private(inode
, file
);
2964 return ERR_PTR(-ENOMEM
);
2967 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
2969 if (tracing_disabled
)
2972 filp
->private_data
= inode
->i_private
;
2976 bool tracing_is_disabled(void)
2978 return (tracing_disabled
) ? true: false;
2982 * Open and update trace_array ref count.
2983 * Must have the current trace_array passed to it.
2985 static int tracing_open_generic_tr(struct inode
*inode
, struct file
*filp
)
2987 struct trace_array
*tr
= inode
->i_private
;
2989 if (tracing_disabled
)
2992 if (trace_array_get(tr
) < 0)
2995 filp
->private_data
= inode
->i_private
;
3000 static int tracing_release(struct inode
*inode
, struct file
*file
)
3002 struct trace_array
*tr
= inode
->i_private
;
3003 struct seq_file
*m
= file
->private_data
;
3004 struct trace_iterator
*iter
;
3007 if (!(file
->f_mode
& FMODE_READ
)) {
3008 trace_array_put(tr
);
3012 /* Writes do not use seq_file */
3014 mutex_lock(&trace_types_lock
);
3016 for_each_tracing_cpu(cpu
) {
3017 if (iter
->buffer_iter
[cpu
])
3018 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
3021 if (iter
->trace
&& iter
->trace
->close
)
3022 iter
->trace
->close(iter
);
3024 if (!iter
->snapshot
)
3025 /* reenable tracing if it was previously enabled */
3026 tracing_start_tr(tr
);
3028 __trace_array_put(tr
);
3030 mutex_unlock(&trace_types_lock
);
3032 mutex_destroy(&iter
->mutex
);
3033 free_cpumask_var(iter
->started
);
3035 kfree(iter
->buffer_iter
);
3036 seq_release_private(inode
, file
);
3041 static int tracing_release_generic_tr(struct inode
*inode
, struct file
*file
)
3043 struct trace_array
*tr
= inode
->i_private
;
3045 trace_array_put(tr
);
3049 static int tracing_single_release_tr(struct inode
*inode
, struct file
*file
)
3051 struct trace_array
*tr
= inode
->i_private
;
3053 trace_array_put(tr
);
3055 return single_release(inode
, file
);
3058 static int tracing_open(struct inode
*inode
, struct file
*file
)
3060 struct trace_array
*tr
= inode
->i_private
;
3061 struct trace_iterator
*iter
;
3064 if (trace_array_get(tr
) < 0)
3067 /* If this file was open for write, then erase contents */
3068 if ((file
->f_mode
& FMODE_WRITE
) && (file
->f_flags
& O_TRUNC
)) {
3069 int cpu
= tracing_get_cpu(inode
);
3071 if (cpu
== RING_BUFFER_ALL_CPUS
)
3072 tracing_reset_online_cpus(&tr
->trace_buffer
);
3074 tracing_reset(&tr
->trace_buffer
, cpu
);
3077 if (file
->f_mode
& FMODE_READ
) {
3078 iter
= __tracing_open(inode
, file
, false);
3080 ret
= PTR_ERR(iter
);
3081 else if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
3082 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
3086 trace_array_put(tr
);
3092 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
3094 struct tracer
*t
= v
;
3104 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
3109 mutex_lock(&trace_types_lock
);
3110 for (t
= trace_types
; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
3116 static void t_stop(struct seq_file
*m
, void *p
)
3118 mutex_unlock(&trace_types_lock
);
3121 static int t_show(struct seq_file
*m
, void *v
)
3123 struct tracer
*t
= v
;
3128 seq_printf(m
, "%s", t
->name
);
3137 static const struct seq_operations show_traces_seq_ops
= {
3144 static int show_traces_open(struct inode
*inode
, struct file
*file
)
3146 if (tracing_disabled
)
3149 return seq_open(file
, &show_traces_seq_ops
);
3153 tracing_write_stub(struct file
*filp
, const char __user
*ubuf
,
3154 size_t count
, loff_t
*ppos
)
3159 static loff_t
tracing_seek(struct file
*file
, loff_t offset
, int origin
)
3161 if (file
->f_mode
& FMODE_READ
)
3162 return seq_lseek(file
, offset
, origin
);
3167 static const struct file_operations tracing_fops
= {
3168 .open
= tracing_open
,
3170 .write
= tracing_write_stub
,
3171 .llseek
= tracing_seek
,
3172 .release
= tracing_release
,
3175 static const struct file_operations show_traces_fops
= {
3176 .open
= show_traces_open
,
3178 .release
= seq_release
,
3179 .llseek
= seq_lseek
,
3183 * The tracer itself will not take this lock, but still we want
3184 * to provide a consistent cpumask to user-space:
3186 static DEFINE_MUTEX(tracing_cpumask_update_lock
);
3189 * Temporary storage for the character representation of the
3190 * CPU bitmask (and one more byte for the newline):
3192 static char mask_str
[NR_CPUS
+ 1];
3195 tracing_cpumask_read(struct file
*filp
, char __user
*ubuf
,
3196 size_t count
, loff_t
*ppos
)
3198 struct trace_array
*tr
= file_inode(filp
)->i_private
;
3201 mutex_lock(&tracing_cpumask_update_lock
);
3203 len
= cpumask_scnprintf(mask_str
, count
, tr
->tracing_cpumask
);
3204 if (count
- len
< 2) {
3208 len
+= sprintf(mask_str
+ len
, "\n");
3209 count
= simple_read_from_buffer(ubuf
, count
, ppos
, mask_str
, NR_CPUS
+1);
3212 mutex_unlock(&tracing_cpumask_update_lock
);
3218 tracing_cpumask_write(struct file
*filp
, const char __user
*ubuf
,
3219 size_t count
, loff_t
*ppos
)
3221 struct trace_array
*tr
= file_inode(filp
)->i_private
;
3222 cpumask_var_t tracing_cpumask_new
;
3225 if (!alloc_cpumask_var(&tracing_cpumask_new
, GFP_KERNEL
))
3228 err
= cpumask_parse_user(ubuf
, count
, tracing_cpumask_new
);
3232 mutex_lock(&tracing_cpumask_update_lock
);
3234 local_irq_disable();
3235 arch_spin_lock(&ftrace_max_lock
);
3236 for_each_tracing_cpu(cpu
) {
3238 * Increase/decrease the disabled counter if we are
3239 * about to flip a bit in the cpumask:
3241 if (cpumask_test_cpu(cpu
, tr
->tracing_cpumask
) &&
3242 !cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
3243 atomic_inc(&per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->disabled
);
3244 ring_buffer_record_disable_cpu(tr
->trace_buffer
.buffer
, cpu
);
3246 if (!cpumask_test_cpu(cpu
, tr
->tracing_cpumask
) &&
3247 cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
3248 atomic_dec(&per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->disabled
);
3249 ring_buffer_record_enable_cpu(tr
->trace_buffer
.buffer
, cpu
);
3252 arch_spin_unlock(&ftrace_max_lock
);
3255 cpumask_copy(tr
->tracing_cpumask
, tracing_cpumask_new
);
3257 mutex_unlock(&tracing_cpumask_update_lock
);
3258 free_cpumask_var(tracing_cpumask_new
);
3263 free_cpumask_var(tracing_cpumask_new
);
3268 static const struct file_operations tracing_cpumask_fops
= {
3269 .open
= tracing_open_generic_tr
,
3270 .read
= tracing_cpumask_read
,
3271 .write
= tracing_cpumask_write
,
3272 .release
= tracing_release_generic_tr
,
3273 .llseek
= generic_file_llseek
,
3276 static int tracing_trace_options_show(struct seq_file
*m
, void *v
)
3278 struct tracer_opt
*trace_opts
;
3279 struct trace_array
*tr
= m
->private;
3283 mutex_lock(&trace_types_lock
);
3284 tracer_flags
= tr
->current_trace
->flags
->val
;
3285 trace_opts
= tr
->current_trace
->flags
->opts
;
3287 for (i
= 0; trace_options
[i
]; i
++) {
3288 if (trace_flags
& (1 << i
))
3289 seq_printf(m
, "%s\n", trace_options
[i
]);
3291 seq_printf(m
, "no%s\n", trace_options
[i
]);
3294 for (i
= 0; trace_opts
[i
].name
; i
++) {
3295 if (tracer_flags
& trace_opts
[i
].bit
)
3296 seq_printf(m
, "%s\n", trace_opts
[i
].name
);
3298 seq_printf(m
, "no%s\n", trace_opts
[i
].name
);
3300 mutex_unlock(&trace_types_lock
);
3305 static int __set_tracer_option(struct tracer
*trace
,
3306 struct tracer_flags
*tracer_flags
,
3307 struct tracer_opt
*opts
, int neg
)
3311 ret
= trace
->set_flag(tracer_flags
->val
, opts
->bit
, !neg
);
3316 tracer_flags
->val
&= ~opts
->bit
;
3318 tracer_flags
->val
|= opts
->bit
;
3322 /* Try to assign a tracer specific option */
3323 static int set_tracer_option(struct tracer
*trace
, char *cmp
, int neg
)
3325 struct tracer_flags
*tracer_flags
= trace
->flags
;
3326 struct tracer_opt
*opts
= NULL
;
3329 for (i
= 0; tracer_flags
->opts
[i
].name
; i
++) {
3330 opts
= &tracer_flags
->opts
[i
];
3332 if (strcmp(cmp
, opts
->name
) == 0)
3333 return __set_tracer_option(trace
, trace
->flags
,
3340 /* Some tracers require overwrite to stay enabled */
3341 int trace_keep_overwrite(struct tracer
*tracer
, u32 mask
, int set
)
3343 if (tracer
->enabled
&& (mask
& TRACE_ITER_OVERWRITE
) && !set
)
3349 int set_tracer_flag(struct trace_array
*tr
, unsigned int mask
, int enabled
)
3351 /* do nothing if flag is already set */
3352 if (!!(trace_flags
& mask
) == !!enabled
)
3355 /* Give the tracer a chance to approve the change */
3356 if (tr
->current_trace
->flag_changed
)
3357 if (tr
->current_trace
->flag_changed(tr
->current_trace
, mask
, !!enabled
))
3361 trace_flags
|= mask
;
3363 trace_flags
&= ~mask
;
3365 if (mask
== TRACE_ITER_RECORD_CMD
)
3366 trace_event_enable_cmd_record(enabled
);
3368 if (mask
== TRACE_ITER_OVERWRITE
) {
3369 ring_buffer_change_overwrite(tr
->trace_buffer
.buffer
, enabled
);
3370 #ifdef CONFIG_TRACER_MAX_TRACE
3371 ring_buffer_change_overwrite(tr
->max_buffer
.buffer
, enabled
);
3375 if (mask
== TRACE_ITER_PRINTK
)
3376 trace_printk_start_stop_comm(enabled
);
3381 static int trace_set_options(struct trace_array
*tr
, char *option
)
3388 cmp
= strstrip(option
);
3390 if (strncmp(cmp
, "no", 2) == 0) {
3395 mutex_lock(&trace_types_lock
);
3397 for (i
= 0; trace_options
[i
]; i
++) {
3398 if (strcmp(cmp
, trace_options
[i
]) == 0) {
3399 ret
= set_tracer_flag(tr
, 1 << i
, !neg
);
3404 /* If no option could be set, test the specific tracer options */
3405 if (!trace_options
[i
])
3406 ret
= set_tracer_option(tr
->current_trace
, cmp
, neg
);
3408 mutex_unlock(&trace_types_lock
);
3414 tracing_trace_options_write(struct file
*filp
, const char __user
*ubuf
,
3415 size_t cnt
, loff_t
*ppos
)
3417 struct seq_file
*m
= filp
->private_data
;
3418 struct trace_array
*tr
= m
->private;
3422 if (cnt
>= sizeof(buf
))
3425 if (copy_from_user(&buf
, ubuf
, cnt
))
3430 ret
= trace_set_options(tr
, buf
);
3439 static int tracing_trace_options_open(struct inode
*inode
, struct file
*file
)
3441 struct trace_array
*tr
= inode
->i_private
;
3444 if (tracing_disabled
)
3447 if (trace_array_get(tr
) < 0)
3450 ret
= single_open(file
, tracing_trace_options_show
, inode
->i_private
);
3452 trace_array_put(tr
);
3457 static const struct file_operations tracing_iter_fops
= {
3458 .open
= tracing_trace_options_open
,
3460 .llseek
= seq_lseek
,
3461 .release
= tracing_single_release_tr
,
3462 .write
= tracing_trace_options_write
,
3465 static const char readme_msg
[] =
3466 "tracing mini-HOWTO:\n\n"
3467 "# echo 0 > tracing_on : quick way to disable tracing\n"
3468 "# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
3469 " Important files:\n"
3470 " trace\t\t\t- The static contents of the buffer\n"
3471 "\t\t\t To clear the buffer write into this file: echo > trace\n"
3472 " trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
3473 " current_tracer\t- function and latency tracers\n"
3474 " available_tracers\t- list of configured tracers for current_tracer\n"
3475 " buffer_size_kb\t- view and modify size of per cpu buffer\n"
3476 " buffer_total_size_kb - view total size of all cpu buffers\n\n"
3477 " trace_clock\t\t-change the clock used to order events\n"
3478 " local: Per cpu clock but may not be synced across CPUs\n"
3479 " global: Synced across CPUs but slows tracing down.\n"
3480 " counter: Not a clock, but just an increment\n"
3481 " uptime: Jiffy counter from time of boot\n"
3482 " perf: Same clock that perf events use\n"
3483 #ifdef CONFIG_X86_64
3484 " x86-tsc: TSC cycle counter\n"
3486 "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
3487 " tracing_cpumask\t- Limit which CPUs to trace\n"
3488 " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
3489 "\t\t\t Remove sub-buffer with rmdir\n"
3490 " trace_options\t\t- Set format or modify how tracing happens\n"
3491 "\t\t\t Disable an option by adding a suffix 'no' to the option name\n"
3492 #ifdef CONFIG_DYNAMIC_FTRACE
3493 "\n available_filter_functions - list of functions that can be filtered on\n"
3494 " set_ftrace_filter\t- echo function name in here to only trace these functions\n"
3495 " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3496 " modules: Can select a group via module\n"
3497 " Format: :mod:<module-name>\n"
3498 " example: echo :mod:ext3 > set_ftrace_filter\n"
3499 " triggers: a command to perform when function is hit\n"
3500 " Format: <function>:<trigger>[:count]\n"
3501 " trigger: traceon, traceoff\n"
3502 " enable_event:<system>:<event>\n"
3503 " disable_event:<system>:<event>\n"
3504 #ifdef CONFIG_STACKTRACE
3507 #ifdef CONFIG_TRACER_SNAPSHOT
3510 " example: echo do_fault:traceoff > set_ftrace_filter\n"
3511 " echo do_trap:traceoff:3 > set_ftrace_filter\n"
3512 " The first one will disable tracing every time do_fault is hit\n"
3513 " The second will disable tracing at most 3 times when do_trap is hit\n"
3514 " The first time do trap is hit and it disables tracing, the counter\n"
3515 " will decrement to 2. If tracing is already disabled, the counter\n"
3516 " will not decrement. It only decrements when the trigger did work\n"
3517 " To remove trigger without count:\n"
3518 " echo '!<function>:<trigger> > set_ftrace_filter\n"
3519 " To remove trigger with a count:\n"
3520 " echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
3521 " set_ftrace_notrace\t- echo function name in here to never trace.\n"
3522 " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3523 " modules: Can select a group via module command :mod:\n"
3524 " Does not accept triggers\n"
3525 #endif /* CONFIG_DYNAMIC_FTRACE */
3526 #ifdef CONFIG_FUNCTION_TRACER
3527 " set_ftrace_pid\t- Write pid(s) to only function trace those pids (function)\n"
3529 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3530 " set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
3531 " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
3533 #ifdef CONFIG_TRACER_SNAPSHOT
3534 "\n snapshot\t\t- Like 'trace' but shows the content of the static snapshot buffer\n"
3535 "\t\t\t Read the contents for more information\n"
3537 #ifdef CONFIG_STACK_TRACER
3538 " stack_trace\t\t- Shows the max stack trace when active\n"
3539 " stack_max_size\t- Shows current max stack size that was traced\n"
3540 "\t\t\t Write into this file to reset the max size (trigger a new trace)\n"
3541 #ifdef CONFIG_DYNAMIC_FTRACE
3542 " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace traces\n"
3544 #endif /* CONFIG_STACK_TRACER */
3548 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
3549 size_t cnt
, loff_t
*ppos
)
3551 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
3552 readme_msg
, strlen(readme_msg
));
3555 static const struct file_operations tracing_readme_fops
= {
3556 .open
= tracing_open_generic
,
3557 .read
= tracing_readme_read
,
3558 .llseek
= generic_file_llseek
,
3562 tracing_saved_cmdlines_read(struct file
*file
, char __user
*ubuf
,
3563 size_t cnt
, loff_t
*ppos
)
3572 file_buf
= kmalloc(SAVED_CMDLINES
*(16+TASK_COMM_LEN
), GFP_KERNEL
);
3576 buf_comm
= kmalloc(TASK_COMM_LEN
, GFP_KERNEL
);
3584 for (i
= 0; i
< SAVED_CMDLINES
; i
++) {
3587 pid
= map_cmdline_to_pid
[i
];
3588 if (pid
== -1 || pid
== NO_CMDLINE_MAP
)
3591 trace_find_cmdline(pid
, buf_comm
);
3592 r
= sprintf(buf
, "%d %s\n", pid
, buf_comm
);
3597 len
= simple_read_from_buffer(ubuf
, cnt
, ppos
,
3606 static const struct file_operations tracing_saved_cmdlines_fops
= {
3607 .open
= tracing_open_generic
,
3608 .read
= tracing_saved_cmdlines_read
,
3609 .llseek
= generic_file_llseek
,
3613 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
3614 size_t cnt
, loff_t
*ppos
)
3616 struct trace_array
*tr
= filp
->private_data
;
3617 char buf
[MAX_TRACER_SIZE
+2];
3620 mutex_lock(&trace_types_lock
);
3621 r
= sprintf(buf
, "%s\n", tr
->current_trace
->name
);
3622 mutex_unlock(&trace_types_lock
);
3624 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3627 int tracer_init(struct tracer
*t
, struct trace_array
*tr
)
3629 tracing_reset_online_cpus(&tr
->trace_buffer
);
3633 static void set_buffer_entries(struct trace_buffer
*buf
, unsigned long val
)
3637 for_each_tracing_cpu(cpu
)
3638 per_cpu_ptr(buf
->data
, cpu
)->entries
= val
;
3641 #ifdef CONFIG_TRACER_MAX_TRACE
3642 /* resize @tr's buffer to the size of @size_tr's entries */
3643 static int resize_buffer_duplicate_size(struct trace_buffer
*trace_buf
,
3644 struct trace_buffer
*size_buf
, int cpu_id
)
3648 if (cpu_id
== RING_BUFFER_ALL_CPUS
) {
3649 for_each_tracing_cpu(cpu
) {
3650 ret
= ring_buffer_resize(trace_buf
->buffer
,
3651 per_cpu_ptr(size_buf
->data
, cpu
)->entries
, cpu
);
3654 per_cpu_ptr(trace_buf
->data
, cpu
)->entries
=
3655 per_cpu_ptr(size_buf
->data
, cpu
)->entries
;
3658 ret
= ring_buffer_resize(trace_buf
->buffer
,
3659 per_cpu_ptr(size_buf
->data
, cpu_id
)->entries
, cpu_id
);
3661 per_cpu_ptr(trace_buf
->data
, cpu_id
)->entries
=
3662 per_cpu_ptr(size_buf
->data
, cpu_id
)->entries
;
3667 #endif /* CONFIG_TRACER_MAX_TRACE */
3669 static int __tracing_resize_ring_buffer(struct trace_array
*tr
,
3670 unsigned long size
, int cpu
)
3675 * If kernel or user changes the size of the ring buffer
3676 * we use the size that was given, and we can forget about
3677 * expanding it later.
3679 ring_buffer_expanded
= true;
3681 /* May be called before buffers are initialized */
3682 if (!tr
->trace_buffer
.buffer
)
3685 ret
= ring_buffer_resize(tr
->trace_buffer
.buffer
, size
, cpu
);
3689 #ifdef CONFIG_TRACER_MAX_TRACE
3690 if (!(tr
->flags
& TRACE_ARRAY_FL_GLOBAL
) ||
3691 !tr
->current_trace
->use_max_tr
)
3694 ret
= ring_buffer_resize(tr
->max_buffer
.buffer
, size
, cpu
);
3696 int r
= resize_buffer_duplicate_size(&tr
->trace_buffer
,
3697 &tr
->trace_buffer
, cpu
);
3700 * AARGH! We are left with different
3701 * size max buffer!!!!
3702 * The max buffer is our "snapshot" buffer.
3703 * When a tracer needs a snapshot (one of the
3704 * latency tracers), it swaps the max buffer
3705 * with the saved snap shot. We succeeded to
3706 * update the size of the main buffer, but failed to
3707 * update the size of the max buffer. But when we tried
3708 * to reset the main buffer to the original size, we
3709 * failed there too. This is very unlikely to
3710 * happen, but if it does, warn and kill all
3714 tracing_disabled
= 1;
3719 if (cpu
== RING_BUFFER_ALL_CPUS
)
3720 set_buffer_entries(&tr
->max_buffer
, size
);
3722 per_cpu_ptr(tr
->max_buffer
.data
, cpu
)->entries
= size
;
3725 #endif /* CONFIG_TRACER_MAX_TRACE */
3727 if (cpu
== RING_BUFFER_ALL_CPUS
)
3728 set_buffer_entries(&tr
->trace_buffer
, size
);
3730 per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
= size
;
3735 static ssize_t
tracing_resize_ring_buffer(struct trace_array
*tr
,
3736 unsigned long size
, int cpu_id
)
3740 mutex_lock(&trace_types_lock
);
3742 if (cpu_id
!= RING_BUFFER_ALL_CPUS
) {
3743 /* make sure, this cpu is enabled in the mask */
3744 if (!cpumask_test_cpu(cpu_id
, tracing_buffer_mask
)) {
3750 ret
= __tracing_resize_ring_buffer(tr
, size
, cpu_id
);
3755 mutex_unlock(&trace_types_lock
);
3762 * tracing_update_buffers - used by tracing facility to expand ring buffers
3764 * To save on memory when the tracing is never used on a system with it
3765 * configured in. The ring buffers are set to a minimum size. But once
3766 * a user starts to use the tracing facility, then they need to grow
3767 * to their default size.
3769 * This function is to be called when a tracer is about to be used.
3771 int tracing_update_buffers(void)
3775 mutex_lock(&trace_types_lock
);
3776 if (!ring_buffer_expanded
)
3777 ret
= __tracing_resize_ring_buffer(&global_trace
, trace_buf_size
,
3778 RING_BUFFER_ALL_CPUS
);
3779 mutex_unlock(&trace_types_lock
);
3784 struct trace_option_dentry
;
3786 static struct trace_option_dentry
*
3787 create_trace_option_files(struct trace_array
*tr
, struct tracer
*tracer
);
3790 destroy_trace_option_files(struct trace_option_dentry
*topts
);
3792 static int tracing_set_tracer(const char *buf
)
3794 static struct trace_option_dentry
*topts
;
3795 struct trace_array
*tr
= &global_trace
;
3797 #ifdef CONFIG_TRACER_MAX_TRACE
3802 mutex_lock(&trace_types_lock
);
3804 if (!ring_buffer_expanded
) {
3805 ret
= __tracing_resize_ring_buffer(tr
, trace_buf_size
,
3806 RING_BUFFER_ALL_CPUS
);
3812 for (t
= trace_types
; t
; t
= t
->next
) {
3813 if (strcmp(t
->name
, buf
) == 0)
3820 if (t
== tr
->current_trace
)
3823 trace_branch_disable();
3825 tr
->current_trace
->enabled
= false;
3827 if (tr
->current_trace
->reset
)
3828 tr
->current_trace
->reset(tr
);
3830 /* Current trace needs to be nop_trace before synchronize_sched */
3831 tr
->current_trace
= &nop_trace
;
3833 #ifdef CONFIG_TRACER_MAX_TRACE
3834 had_max_tr
= tr
->allocated_snapshot
;
3836 if (had_max_tr
&& !t
->use_max_tr
) {
3838 * We need to make sure that the update_max_tr sees that
3839 * current_trace changed to nop_trace to keep it from
3840 * swapping the buffers after we resize it.
3841 * The update_max_tr is called from interrupts disabled
3842 * so a synchronized_sched() is sufficient.
3844 synchronize_sched();
3848 destroy_trace_option_files(topts
);
3850 topts
= create_trace_option_files(tr
, t
);
3852 #ifdef CONFIG_TRACER_MAX_TRACE
3853 if (t
->use_max_tr
&& !had_max_tr
) {
3854 ret
= alloc_snapshot(tr
);
3861 ret
= tracer_init(t
, tr
);
3866 tr
->current_trace
= t
;
3867 tr
->current_trace
->enabled
= true;
3868 trace_branch_enable(tr
);
3870 mutex_unlock(&trace_types_lock
);
3876 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
3877 size_t cnt
, loff_t
*ppos
)
3879 char buf
[MAX_TRACER_SIZE
+1];
3886 if (cnt
> MAX_TRACER_SIZE
)
3887 cnt
= MAX_TRACER_SIZE
;
3889 if (copy_from_user(&buf
, ubuf
, cnt
))
3894 /* strip ending whitespace. */
3895 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
3898 err
= tracing_set_tracer(buf
);
3908 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
3909 size_t cnt
, loff_t
*ppos
)
3911 unsigned long *ptr
= filp
->private_data
;
3915 r
= snprintf(buf
, sizeof(buf
), "%ld\n",
3916 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
3917 if (r
> sizeof(buf
))
3919 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3923 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
3924 size_t cnt
, loff_t
*ppos
)
3926 unsigned long *ptr
= filp
->private_data
;
3930 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
3939 static int tracing_open_pipe(struct inode
*inode
, struct file
*filp
)
3941 struct trace_array
*tr
= inode
->i_private
;
3942 struct trace_iterator
*iter
;
3945 if (tracing_disabled
)
3948 if (trace_array_get(tr
) < 0)
3951 mutex_lock(&trace_types_lock
);
3953 /* create a buffer to store the information to pass to userspace */
3954 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
3957 __trace_array_put(tr
);
3962 * We make a copy of the current tracer to avoid concurrent
3963 * changes on it while we are reading.
3965 iter
->trace
= kmalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
3970 *iter
->trace
= *tr
->current_trace
;
3972 if (!alloc_cpumask_var(&iter
->started
, GFP_KERNEL
)) {
3977 /* trace pipe does not show start of buffer */
3978 cpumask_setall(iter
->started
);
3980 if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
3981 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
3983 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
3984 if (trace_clocks
[tr
->clock_id
].in_ns
)
3985 iter
->iter_flags
|= TRACE_FILE_TIME_IN_NS
;
3988 iter
->trace_buffer
= &tr
->trace_buffer
;
3989 iter
->cpu_file
= tracing_get_cpu(inode
);
3990 mutex_init(&iter
->mutex
);
3991 filp
->private_data
= iter
;
3993 if (iter
->trace
->pipe_open
)
3994 iter
->trace
->pipe_open(iter
);
3996 nonseekable_open(inode
, filp
);
3998 mutex_unlock(&trace_types_lock
);
4004 __trace_array_put(tr
);
4005 mutex_unlock(&trace_types_lock
);
4009 static int tracing_release_pipe(struct inode
*inode
, struct file
*file
)
4011 struct trace_iterator
*iter
= file
->private_data
;
4012 struct trace_array
*tr
= inode
->i_private
;
4014 mutex_lock(&trace_types_lock
);
4016 if (iter
->trace
->pipe_close
)
4017 iter
->trace
->pipe_close(iter
);
4019 mutex_unlock(&trace_types_lock
);
4021 free_cpumask_var(iter
->started
);
4022 mutex_destroy(&iter
->mutex
);
4026 trace_array_put(tr
);
4032 trace_poll(struct trace_iterator
*iter
, struct file
*filp
, poll_table
*poll_table
)
4034 /* Iterators are static, they should be filled or empty */
4035 if (trace_buffer_iter(iter
, iter
->cpu_file
))
4036 return POLLIN
| POLLRDNORM
;
4038 if (trace_flags
& TRACE_ITER_BLOCK
)
4040 * Always select as readable when in blocking mode
4042 return POLLIN
| POLLRDNORM
;
4044 return ring_buffer_poll_wait(iter
->trace_buffer
->buffer
, iter
->cpu_file
,
4049 tracing_poll_pipe(struct file
*filp
, poll_table
*poll_table
)
4051 struct trace_iterator
*iter
= filp
->private_data
;
4053 return trace_poll(iter
, filp
, poll_table
);
4057 * This is a make-shift waitqueue.
4058 * A tracer might use this callback on some rare cases:
4060 * 1) the current tracer might hold the runqueue lock when it wakes up
4061 * a reader, hence a deadlock (sched, function, and function graph tracers)
4062 * 2) the function tracers, trace all functions, we don't want
4063 * the overhead of calling wake_up and friends
4064 * (and tracing them too)
4066 * Anyway, this is really very primitive wakeup.
4068 void poll_wait_pipe(struct trace_iterator
*iter
)
4070 set_current_state(TASK_INTERRUPTIBLE
);
4071 /* sleep for 100 msecs, and try again. */
4072 schedule_timeout(HZ
/ 10);
4075 /* Must be called with trace_types_lock mutex held. */
4076 static int tracing_wait_pipe(struct file
*filp
)
4078 struct trace_iterator
*iter
= filp
->private_data
;
4080 while (trace_empty(iter
)) {
4082 if ((filp
->f_flags
& O_NONBLOCK
)) {
4086 mutex_unlock(&iter
->mutex
);
4088 iter
->trace
->wait_pipe(iter
);
4090 mutex_lock(&iter
->mutex
);
4092 if (signal_pending(current
))
4096 * We block until we read something and tracing is disabled.
4097 * We still block if tracing is disabled, but we have never
4098 * read anything. This allows a user to cat this file, and
4099 * then enable tracing. But after we have read something,
4100 * we give an EOF when tracing is again disabled.
4102 * iter->pos will be 0 if we haven't read anything.
4104 if (!tracing_is_on() && iter
->pos
)
4115 tracing_read_pipe(struct file
*filp
, char __user
*ubuf
,
4116 size_t cnt
, loff_t
*ppos
)
4118 struct trace_iterator
*iter
= filp
->private_data
;
4119 struct trace_array
*tr
= iter
->tr
;
4122 /* return any leftover data */
4123 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
4127 trace_seq_init(&iter
->seq
);
4129 /* copy the tracer to avoid using a global lock all around */
4130 mutex_lock(&trace_types_lock
);
4131 if (unlikely(iter
->trace
->name
!= tr
->current_trace
->name
))
4132 *iter
->trace
= *tr
->current_trace
;
4133 mutex_unlock(&trace_types_lock
);
4136 * Avoid more than one consumer on a single file descriptor
4137 * This is just a matter of traces coherency, the ring buffer itself
4140 mutex_lock(&iter
->mutex
);
4141 if (iter
->trace
->read
) {
4142 sret
= iter
->trace
->read(iter
, filp
, ubuf
, cnt
, ppos
);
4148 sret
= tracing_wait_pipe(filp
);
4152 /* stop when tracing is finished */
4153 if (trace_empty(iter
)) {
4158 if (cnt
>= PAGE_SIZE
)
4159 cnt
= PAGE_SIZE
- 1;
4161 /* reset all but tr, trace, and overruns */
4162 memset(&iter
->seq
, 0,
4163 sizeof(struct trace_iterator
) -
4164 offsetof(struct trace_iterator
, seq
));
4165 cpumask_clear(iter
->started
);
4168 trace_event_read_lock();
4169 trace_access_lock(iter
->cpu_file
);
4170 while (trace_find_next_entry_inc(iter
) != NULL
) {
4171 enum print_line_t ret
;
4172 int len
= iter
->seq
.len
;
4174 ret
= print_trace_line(iter
);
4175 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
4176 /* don't print partial lines */
4177 iter
->seq
.len
= len
;
4180 if (ret
!= TRACE_TYPE_NO_CONSUME
)
4181 trace_consume(iter
);
4183 if (iter
->seq
.len
>= cnt
)
4187 * Setting the full flag means we reached the trace_seq buffer
4188 * size and we should leave by partial output condition above.
4189 * One of the trace_seq_* functions is not used properly.
4191 WARN_ONCE(iter
->seq
.full
, "full flag set for trace type %d",
4194 trace_access_unlock(iter
->cpu_file
);
4195 trace_event_read_unlock();
4197 /* Now copy what we have to the user */
4198 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
4199 if (iter
->seq
.readpos
>= iter
->seq
.len
)
4200 trace_seq_init(&iter
->seq
);
4203 * If there was nothing to send to user, in spite of consuming trace
4204 * entries, go back to wait for more entries.
4210 mutex_unlock(&iter
->mutex
);
4215 static void tracing_pipe_buf_release(struct pipe_inode_info
*pipe
,
4216 struct pipe_buffer
*buf
)
4218 __free_page(buf
->page
);
4221 static void tracing_spd_release_pipe(struct splice_pipe_desc
*spd
,
4224 __free_page(spd
->pages
[idx
]);
4227 static const struct pipe_buf_operations tracing_pipe_buf_ops
= {
4229 .map
= generic_pipe_buf_map
,
4230 .unmap
= generic_pipe_buf_unmap
,
4231 .confirm
= generic_pipe_buf_confirm
,
4232 .release
= tracing_pipe_buf_release
,
4233 .steal
= generic_pipe_buf_steal
,
4234 .get
= generic_pipe_buf_get
,
4238 tracing_fill_pipe_page(size_t rem
, struct trace_iterator
*iter
)
4243 /* Seq buffer is page-sized, exactly what we need. */
4245 count
= iter
->seq
.len
;
4246 ret
= print_trace_line(iter
);
4247 count
= iter
->seq
.len
- count
;
4250 iter
->seq
.len
-= count
;
4253 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
4254 iter
->seq
.len
-= count
;
4258 if (ret
!= TRACE_TYPE_NO_CONSUME
)
4259 trace_consume(iter
);
4261 if (!trace_find_next_entry_inc(iter
)) {
4271 static ssize_t
tracing_splice_read_pipe(struct file
*filp
,
4273 struct pipe_inode_info
*pipe
,
4277 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
4278 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
4279 struct trace_iterator
*iter
= filp
->private_data
;
4280 struct splice_pipe_desc spd
= {
4282 .partial
= partial_def
,
4283 .nr_pages
= 0, /* This gets updated below. */
4284 .nr_pages_max
= PIPE_DEF_BUFFERS
,
4286 .ops
= &tracing_pipe_buf_ops
,
4287 .spd_release
= tracing_spd_release_pipe
,
4289 struct trace_array
*tr
= iter
->tr
;
4294 if (splice_grow_spd(pipe
, &spd
))
4297 /* copy the tracer to avoid using a global lock all around */
4298 mutex_lock(&trace_types_lock
);
4299 if (unlikely(iter
->trace
->name
!= tr
->current_trace
->name
))
4300 *iter
->trace
= *tr
->current_trace
;
4301 mutex_unlock(&trace_types_lock
);
4303 mutex_lock(&iter
->mutex
);
4305 if (iter
->trace
->splice_read
) {
4306 ret
= iter
->trace
->splice_read(iter
, filp
,
4307 ppos
, pipe
, len
, flags
);
4312 ret
= tracing_wait_pipe(filp
);
4316 if (!iter
->ent
&& !trace_find_next_entry_inc(iter
)) {
4321 trace_event_read_lock();
4322 trace_access_lock(iter
->cpu_file
);
4324 /* Fill as many pages as possible. */
4325 for (i
= 0, rem
= len
; i
< pipe
->buffers
&& rem
; i
++) {
4326 spd
.pages
[i
] = alloc_page(GFP_KERNEL
);
4330 rem
= tracing_fill_pipe_page(rem
, iter
);
4332 /* Copy the data into the page, so we can start over. */
4333 ret
= trace_seq_to_buffer(&iter
->seq
,
4334 page_address(spd
.pages
[i
]),
4337 __free_page(spd
.pages
[i
]);
4340 spd
.partial
[i
].offset
= 0;
4341 spd
.partial
[i
].len
= iter
->seq
.len
;
4343 trace_seq_init(&iter
->seq
);
4346 trace_access_unlock(iter
->cpu_file
);
4347 trace_event_read_unlock();
4348 mutex_unlock(&iter
->mutex
);
4352 ret
= splice_to_pipe(pipe
, &spd
);
4354 splice_shrink_spd(&spd
);
4358 mutex_unlock(&iter
->mutex
);
4363 tracing_entries_read(struct file
*filp
, char __user
*ubuf
,
4364 size_t cnt
, loff_t
*ppos
)
4366 struct inode
*inode
= file_inode(filp
);
4367 struct trace_array
*tr
= inode
->i_private
;
4368 int cpu
= tracing_get_cpu(inode
);
4373 mutex_lock(&trace_types_lock
);
4375 if (cpu
== RING_BUFFER_ALL_CPUS
) {
4376 int cpu
, buf_size_same
;
4381 /* check if all cpu sizes are same */
4382 for_each_tracing_cpu(cpu
) {
4383 /* fill in the size from first enabled cpu */
4385 size
= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
;
4386 if (size
!= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
) {
4392 if (buf_size_same
) {
4393 if (!ring_buffer_expanded
)
4394 r
= sprintf(buf
, "%lu (expanded: %lu)\n",
4396 trace_buf_size
>> 10);
4398 r
= sprintf(buf
, "%lu\n", size
>> 10);
4400 r
= sprintf(buf
, "X\n");
4402 r
= sprintf(buf
, "%lu\n", per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
>> 10);
4404 mutex_unlock(&trace_types_lock
);
4406 ret
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
4411 tracing_entries_write(struct file
*filp
, const char __user
*ubuf
,
4412 size_t cnt
, loff_t
*ppos
)
4414 struct inode
*inode
= file_inode(filp
);
4415 struct trace_array
*tr
= inode
->i_private
;
4419 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
4423 /* must have at least 1 entry */
4427 /* value is in KB */
4429 ret
= tracing_resize_ring_buffer(tr
, val
, tracing_get_cpu(inode
));
4439 tracing_total_entries_read(struct file
*filp
, char __user
*ubuf
,
4440 size_t cnt
, loff_t
*ppos
)
4442 struct trace_array
*tr
= filp
->private_data
;
4445 unsigned long size
= 0, expanded_size
= 0;
4447 mutex_lock(&trace_types_lock
);
4448 for_each_tracing_cpu(cpu
) {
4449 size
+= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
>> 10;
4450 if (!ring_buffer_expanded
)
4451 expanded_size
+= trace_buf_size
>> 10;
4453 if (ring_buffer_expanded
)
4454 r
= sprintf(buf
, "%lu\n", size
);
4456 r
= sprintf(buf
, "%lu (expanded: %lu)\n", size
, expanded_size
);
4457 mutex_unlock(&trace_types_lock
);
4459 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
4463 tracing_free_buffer_write(struct file
*filp
, const char __user
*ubuf
,
4464 size_t cnt
, loff_t
*ppos
)
4467 * There is no need to read what the user has written, this function
4468 * is just to make sure that there is no error when "echo" is used
4477 tracing_free_buffer_release(struct inode
*inode
, struct file
*filp
)
4479 struct trace_array
*tr
= inode
->i_private
;
4481 /* disable tracing ? */
4482 if (trace_flags
& TRACE_ITER_STOP_ON_FREE
)
4483 tracer_tracing_off(tr
);
4484 /* resize the ring buffer to 0 */
4485 tracing_resize_ring_buffer(tr
, 0, RING_BUFFER_ALL_CPUS
);
4487 trace_array_put(tr
);
4493 tracing_mark_write(struct file
*filp
, const char __user
*ubuf
,
4494 size_t cnt
, loff_t
*fpos
)
4496 unsigned long addr
= (unsigned long)ubuf
;
4497 struct trace_array
*tr
= filp
->private_data
;
4498 struct ring_buffer_event
*event
;
4499 struct ring_buffer
*buffer
;
4500 struct print_entry
*entry
;
4501 unsigned long irq_flags
;
4502 struct page
*pages
[2];
4512 if (tracing_disabled
)
4515 if (!(trace_flags
& TRACE_ITER_MARKERS
))
4518 if (cnt
> TRACE_BUF_SIZE
)
4519 cnt
= TRACE_BUF_SIZE
;
4522 * Userspace is injecting traces into the kernel trace buffer.
4523 * We want to be as non intrusive as possible.
4524 * To do so, we do not want to allocate any special buffers
4525 * or take any locks, but instead write the userspace data
4526 * straight into the ring buffer.
4528 * First we need to pin the userspace buffer into memory,
4529 * which, most likely it is, because it just referenced it.
4530 * But there's no guarantee that it is. By using get_user_pages_fast()
4531 * and kmap_atomic/kunmap_atomic() we can get access to the
4532 * pages directly. We then write the data directly into the
4535 BUILD_BUG_ON(TRACE_BUF_SIZE
>= PAGE_SIZE
);
4537 /* check if we cross pages */
4538 if ((addr
& PAGE_MASK
) != ((addr
+ cnt
) & PAGE_MASK
))
4541 offset
= addr
& (PAGE_SIZE
- 1);
4544 ret
= get_user_pages_fast(addr
, nr_pages
, 0, pages
);
4545 if (ret
< nr_pages
) {
4547 put_page(pages
[ret
]);
4552 for (i
= 0; i
< nr_pages
; i
++)
4553 map_page
[i
] = kmap_atomic(pages
[i
]);
4555 local_save_flags(irq_flags
);
4556 size
= sizeof(*entry
) + cnt
+ 2; /* possible \n added */
4557 buffer
= tr
->trace_buffer
.buffer
;
4558 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, size
,
4559 irq_flags
, preempt_count());
4561 /* Ring buffer disabled, return as if not open for write */
4566 entry
= ring_buffer_event_data(event
);
4567 entry
->ip
= _THIS_IP_
;
4569 if (nr_pages
== 2) {
4570 len
= PAGE_SIZE
- offset
;
4571 memcpy(&entry
->buf
, map_page
[0] + offset
, len
);
4572 memcpy(&entry
->buf
[len
], map_page
[1], cnt
- len
);
4574 memcpy(&entry
->buf
, map_page
[0] + offset
, cnt
);
4576 if (entry
->buf
[cnt
- 1] != '\n') {
4577 entry
->buf
[cnt
] = '\n';
4578 entry
->buf
[cnt
+ 1] = '\0';
4580 entry
->buf
[cnt
] = '\0';
4582 __buffer_unlock_commit(buffer
, event
);
4589 for (i
= 0; i
< nr_pages
; i
++){
4590 kunmap_atomic(map_page
[i
]);
4597 static int tracing_clock_show(struct seq_file
*m
, void *v
)
4599 struct trace_array
*tr
= m
->private;
4602 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++)
4604 "%s%s%s%s", i
? " " : "",
4605 i
== tr
->clock_id
? "[" : "", trace_clocks
[i
].name
,
4606 i
== tr
->clock_id
? "]" : "");
4612 static ssize_t
tracing_clock_write(struct file
*filp
, const char __user
*ubuf
,
4613 size_t cnt
, loff_t
*fpos
)
4615 struct seq_file
*m
= filp
->private_data
;
4616 struct trace_array
*tr
= m
->private;
4618 const char *clockstr
;
4621 if (cnt
>= sizeof(buf
))
4624 if (copy_from_user(&buf
, ubuf
, cnt
))
4629 clockstr
= strstrip(buf
);
4631 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++) {
4632 if (strcmp(trace_clocks
[i
].name
, clockstr
) == 0)
4635 if (i
== ARRAY_SIZE(trace_clocks
))
4638 mutex_lock(&trace_types_lock
);
4642 ring_buffer_set_clock(tr
->trace_buffer
.buffer
, trace_clocks
[i
].func
);
4645 * New clock may not be consistent with the previous clock.
4646 * Reset the buffer so that it doesn't have incomparable timestamps.
4648 tracing_reset_online_cpus(&tr
->trace_buffer
);
4650 #ifdef CONFIG_TRACER_MAX_TRACE
4651 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
&& tr
->max_buffer
.buffer
)
4652 ring_buffer_set_clock(tr
->max_buffer
.buffer
, trace_clocks
[i
].func
);
4653 tracing_reset_online_cpus(&tr
->max_buffer
);
4656 mutex_unlock(&trace_types_lock
);
4663 static int tracing_clock_open(struct inode
*inode
, struct file
*file
)
4665 struct trace_array
*tr
= inode
->i_private
;
4668 if (tracing_disabled
)
4671 if (trace_array_get(tr
))
4674 ret
= single_open(file
, tracing_clock_show
, inode
->i_private
);
4676 trace_array_put(tr
);
4681 struct ftrace_buffer_info
{
4682 struct trace_iterator iter
;
4687 #ifdef CONFIG_TRACER_SNAPSHOT
4688 static int tracing_snapshot_open(struct inode
*inode
, struct file
*file
)
4690 struct trace_array
*tr
= inode
->i_private
;
4691 struct trace_iterator
*iter
;
4695 if (trace_array_get(tr
) < 0)
4698 if (file
->f_mode
& FMODE_READ
) {
4699 iter
= __tracing_open(inode
, file
, true);
4701 ret
= PTR_ERR(iter
);
4703 /* Writes still need the seq_file to hold the private data */
4705 m
= kzalloc(sizeof(*m
), GFP_KERNEL
);
4708 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
4716 iter
->trace_buffer
= &tr
->max_buffer
;
4717 iter
->cpu_file
= tracing_get_cpu(inode
);
4719 file
->private_data
= m
;
4723 trace_array_put(tr
);
4729 tracing_snapshot_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
4732 struct seq_file
*m
= filp
->private_data
;
4733 struct trace_iterator
*iter
= m
->private;
4734 struct trace_array
*tr
= iter
->tr
;
4738 ret
= tracing_update_buffers();
4742 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
4746 mutex_lock(&trace_types_lock
);
4748 if (tr
->current_trace
->use_max_tr
) {
4755 if (iter
->cpu_file
!= RING_BUFFER_ALL_CPUS
) {
4759 if (tr
->allocated_snapshot
)
4763 /* Only allow per-cpu swap if the ring buffer supports it */
4764 #ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
4765 if (iter
->cpu_file
!= RING_BUFFER_ALL_CPUS
) {
4770 if (!tr
->allocated_snapshot
) {
4771 ret
= alloc_snapshot(tr
);
4775 local_irq_disable();
4776 /* Now, we're going to swap */
4777 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
)
4778 update_max_tr(tr
, current
, smp_processor_id());
4780 update_max_tr_single(tr
, current
, iter
->cpu_file
);
4784 if (tr
->allocated_snapshot
) {
4785 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
)
4786 tracing_reset_online_cpus(&tr
->max_buffer
);
4788 tracing_reset(&tr
->max_buffer
, iter
->cpu_file
);
4798 mutex_unlock(&trace_types_lock
);
4802 static int tracing_snapshot_release(struct inode
*inode
, struct file
*file
)
4804 struct seq_file
*m
= file
->private_data
;
4807 ret
= tracing_release(inode
, file
);
4809 if (file
->f_mode
& FMODE_READ
)
4812 /* If write only, the seq_file is just a stub */
4820 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
);
4821 static ssize_t
tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
4822 size_t count
, loff_t
*ppos
);
4823 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
);
4824 static ssize_t
tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
4825 struct pipe_inode_info
*pipe
, size_t len
, unsigned int flags
);
4827 static int snapshot_raw_open(struct inode
*inode
, struct file
*filp
)
4829 struct ftrace_buffer_info
*info
;
4832 ret
= tracing_buffers_open(inode
, filp
);
4836 info
= filp
->private_data
;
4838 if (info
->iter
.trace
->use_max_tr
) {
4839 tracing_buffers_release(inode
, filp
);
4843 info
->iter
.snapshot
= true;
4844 info
->iter
.trace_buffer
= &info
->iter
.tr
->max_buffer
;
4849 #endif /* CONFIG_TRACER_SNAPSHOT */
4852 static const struct file_operations tracing_max_lat_fops
= {
4853 .open
= tracing_open_generic
,
4854 .read
= tracing_max_lat_read
,
4855 .write
= tracing_max_lat_write
,
4856 .llseek
= generic_file_llseek
,
4859 static const struct file_operations set_tracer_fops
= {
4860 .open
= tracing_open_generic
,
4861 .read
= tracing_set_trace_read
,
4862 .write
= tracing_set_trace_write
,
4863 .llseek
= generic_file_llseek
,
4866 static const struct file_operations tracing_pipe_fops
= {
4867 .open
= tracing_open_pipe
,
4868 .poll
= tracing_poll_pipe
,
4869 .read
= tracing_read_pipe
,
4870 .splice_read
= tracing_splice_read_pipe
,
4871 .release
= tracing_release_pipe
,
4872 .llseek
= no_llseek
,
4875 static const struct file_operations tracing_entries_fops
= {
4876 .open
= tracing_open_generic_tr
,
4877 .read
= tracing_entries_read
,
4878 .write
= tracing_entries_write
,
4879 .llseek
= generic_file_llseek
,
4880 .release
= tracing_release_generic_tr
,
4883 static const struct file_operations tracing_total_entries_fops
= {
4884 .open
= tracing_open_generic_tr
,
4885 .read
= tracing_total_entries_read
,
4886 .llseek
= generic_file_llseek
,
4887 .release
= tracing_release_generic_tr
,
4890 static const struct file_operations tracing_free_buffer_fops
= {
4891 .open
= tracing_open_generic_tr
,
4892 .write
= tracing_free_buffer_write
,
4893 .release
= tracing_free_buffer_release
,
4896 static const struct file_operations tracing_mark_fops
= {
4897 .open
= tracing_open_generic_tr
,
4898 .write
= tracing_mark_write
,
4899 .llseek
= generic_file_llseek
,
4900 .release
= tracing_release_generic_tr
,
4903 static const struct file_operations trace_clock_fops
= {
4904 .open
= tracing_clock_open
,
4906 .llseek
= seq_lseek
,
4907 .release
= tracing_single_release_tr
,
4908 .write
= tracing_clock_write
,
4911 #ifdef CONFIG_TRACER_SNAPSHOT
4912 static const struct file_operations snapshot_fops
= {
4913 .open
= tracing_snapshot_open
,
4915 .write
= tracing_snapshot_write
,
4916 .llseek
= tracing_seek
,
4917 .release
= tracing_snapshot_release
,
4920 static const struct file_operations snapshot_raw_fops
= {
4921 .open
= snapshot_raw_open
,
4922 .read
= tracing_buffers_read
,
4923 .release
= tracing_buffers_release
,
4924 .splice_read
= tracing_buffers_splice_read
,
4925 .llseek
= no_llseek
,
4928 #endif /* CONFIG_TRACER_SNAPSHOT */
4930 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
)
4932 struct trace_array
*tr
= inode
->i_private
;
4933 struct ftrace_buffer_info
*info
;
4936 if (tracing_disabled
)
4939 if (trace_array_get(tr
) < 0)
4942 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
4944 trace_array_put(tr
);
4948 mutex_lock(&trace_types_lock
);
4951 info
->iter
.cpu_file
= tracing_get_cpu(inode
);
4952 info
->iter
.trace
= tr
->current_trace
;
4953 info
->iter
.trace_buffer
= &tr
->trace_buffer
;
4955 /* Force reading ring buffer for first read */
4956 info
->read
= (unsigned int)-1;
4958 filp
->private_data
= info
;
4960 mutex_unlock(&trace_types_lock
);
4962 ret
= nonseekable_open(inode
, filp
);
4964 trace_array_put(tr
);
4970 tracing_buffers_poll(struct file
*filp
, poll_table
*poll_table
)
4972 struct ftrace_buffer_info
*info
= filp
->private_data
;
4973 struct trace_iterator
*iter
= &info
->iter
;
4975 return trace_poll(iter
, filp
, poll_table
);
4979 tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
4980 size_t count
, loff_t
*ppos
)
4982 struct ftrace_buffer_info
*info
= filp
->private_data
;
4983 struct trace_iterator
*iter
= &info
->iter
;
4990 mutex_lock(&trace_types_lock
);
4992 #ifdef CONFIG_TRACER_MAX_TRACE
4993 if (iter
->snapshot
&& iter
->tr
->current_trace
->use_max_tr
) {
5000 info
->spare
= ring_buffer_alloc_read_page(iter
->trace_buffer
->buffer
,
5006 /* Do we have previous read data to read? */
5007 if (info
->read
< PAGE_SIZE
)
5011 trace_access_lock(iter
->cpu_file
);
5012 ret
= ring_buffer_read_page(iter
->trace_buffer
->buffer
,
5016 trace_access_unlock(iter
->cpu_file
);
5019 if (trace_empty(iter
)) {
5020 if ((filp
->f_flags
& O_NONBLOCK
)) {
5024 mutex_unlock(&trace_types_lock
);
5025 iter
->trace
->wait_pipe(iter
);
5026 mutex_lock(&trace_types_lock
);
5027 if (signal_pending(current
)) {
5039 size
= PAGE_SIZE
- info
->read
;
5043 ret
= copy_to_user(ubuf
, info
->spare
+ info
->read
, size
);
5054 mutex_unlock(&trace_types_lock
);
5059 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
)
5061 struct ftrace_buffer_info
*info
= file
->private_data
;
5062 struct trace_iterator
*iter
= &info
->iter
;
5064 mutex_lock(&trace_types_lock
);
5066 __trace_array_put(iter
->tr
);
5069 ring_buffer_free_read_page(iter
->trace_buffer
->buffer
, info
->spare
);
5072 mutex_unlock(&trace_types_lock
);
5078 struct ring_buffer
*buffer
;
5083 static void buffer_pipe_buf_release(struct pipe_inode_info
*pipe
,
5084 struct pipe_buffer
*buf
)
5086 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
5091 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
5096 static void buffer_pipe_buf_get(struct pipe_inode_info
*pipe
,
5097 struct pipe_buffer
*buf
)
5099 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
5104 /* Pipe buffer operations for a buffer. */
5105 static const struct pipe_buf_operations buffer_pipe_buf_ops
= {
5107 .map
= generic_pipe_buf_map
,
5108 .unmap
= generic_pipe_buf_unmap
,
5109 .confirm
= generic_pipe_buf_confirm
,
5110 .release
= buffer_pipe_buf_release
,
5111 .steal
= generic_pipe_buf_steal
,
5112 .get
= buffer_pipe_buf_get
,
5116 * Callback from splice_to_pipe(), if we need to release some pages
5117 * at the end of the spd in case we error'ed out in filling the pipe.
5119 static void buffer_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
5121 struct buffer_ref
*ref
=
5122 (struct buffer_ref
*)spd
->partial
[i
].private;
5127 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
5129 spd
->partial
[i
].private = 0;
5133 tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
5134 struct pipe_inode_info
*pipe
, size_t len
,
5137 struct ftrace_buffer_info
*info
= file
->private_data
;
5138 struct trace_iterator
*iter
= &info
->iter
;
5139 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
5140 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
5141 struct splice_pipe_desc spd
= {
5143 .partial
= partial_def
,
5144 .nr_pages_max
= PIPE_DEF_BUFFERS
,
5146 .ops
= &buffer_pipe_buf_ops
,
5147 .spd_release
= buffer_spd_release
,
5149 struct buffer_ref
*ref
;
5150 int entries
, size
, i
;
5153 mutex_lock(&trace_types_lock
);
5155 #ifdef CONFIG_TRACER_MAX_TRACE
5156 if (iter
->snapshot
&& iter
->tr
->current_trace
->use_max_tr
) {
5162 if (splice_grow_spd(pipe
, &spd
)) {
5167 if (*ppos
& (PAGE_SIZE
- 1)) {
5172 if (len
& (PAGE_SIZE
- 1)) {
5173 if (len
< PAGE_SIZE
) {
5181 trace_access_lock(iter
->cpu_file
);
5182 entries
= ring_buffer_entries_cpu(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
5184 for (i
= 0; i
< pipe
->buffers
&& len
&& entries
; i
++, len
-= PAGE_SIZE
) {
5188 ref
= kzalloc(sizeof(*ref
), GFP_KERNEL
);
5193 ref
->buffer
= iter
->trace_buffer
->buffer
;
5194 ref
->page
= ring_buffer_alloc_read_page(ref
->buffer
, iter
->cpu_file
);
5200 r
= ring_buffer_read_page(ref
->buffer
, &ref
->page
,
5201 len
, iter
->cpu_file
, 1);
5203 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
5209 * zero out any left over data, this is going to
5212 size
= ring_buffer_page_len(ref
->page
);
5213 if (size
< PAGE_SIZE
)
5214 memset(ref
->page
+ size
, 0, PAGE_SIZE
- size
);
5216 page
= virt_to_page(ref
->page
);
5218 spd
.pages
[i
] = page
;
5219 spd
.partial
[i
].len
= PAGE_SIZE
;
5220 spd
.partial
[i
].offset
= 0;
5221 spd
.partial
[i
].private = (unsigned long)ref
;
5225 entries
= ring_buffer_entries_cpu(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
5228 trace_access_unlock(iter
->cpu_file
);
5231 /* did we read anything? */
5232 if (!spd
.nr_pages
) {
5233 if ((file
->f_flags
& O_NONBLOCK
) || (flags
& SPLICE_F_NONBLOCK
)) {
5237 mutex_unlock(&trace_types_lock
);
5238 iter
->trace
->wait_pipe(iter
);
5239 mutex_lock(&trace_types_lock
);
5240 if (signal_pending(current
)) {
5247 ret
= splice_to_pipe(pipe
, &spd
);
5248 splice_shrink_spd(&spd
);
5250 mutex_unlock(&trace_types_lock
);
5255 static const struct file_operations tracing_buffers_fops
= {
5256 .open
= tracing_buffers_open
,
5257 .read
= tracing_buffers_read
,
5258 .poll
= tracing_buffers_poll
,
5259 .release
= tracing_buffers_release
,
5260 .splice_read
= tracing_buffers_splice_read
,
5261 .llseek
= no_llseek
,
5265 tracing_stats_read(struct file
*filp
, char __user
*ubuf
,
5266 size_t count
, loff_t
*ppos
)
5268 struct inode
*inode
= file_inode(filp
);
5269 struct trace_array
*tr
= inode
->i_private
;
5270 struct trace_buffer
*trace_buf
= &tr
->trace_buffer
;
5271 int cpu
= tracing_get_cpu(inode
);
5272 struct trace_seq
*s
;
5274 unsigned long long t
;
5275 unsigned long usec_rem
;
5277 s
= kmalloc(sizeof(*s
), GFP_KERNEL
);
5283 cnt
= ring_buffer_entries_cpu(trace_buf
->buffer
, cpu
);
5284 trace_seq_printf(s
, "entries: %ld\n", cnt
);
5286 cnt
= ring_buffer_overrun_cpu(trace_buf
->buffer
, cpu
);
5287 trace_seq_printf(s
, "overrun: %ld\n", cnt
);
5289 cnt
= ring_buffer_commit_overrun_cpu(trace_buf
->buffer
, cpu
);
5290 trace_seq_printf(s
, "commit overrun: %ld\n", cnt
);
5292 cnt
= ring_buffer_bytes_cpu(trace_buf
->buffer
, cpu
);
5293 trace_seq_printf(s
, "bytes: %ld\n", cnt
);
5295 if (trace_clocks
[tr
->clock_id
].in_ns
) {
5296 /* local or global for trace_clock */
5297 t
= ns2usecs(ring_buffer_oldest_event_ts(trace_buf
->buffer
, cpu
));
5298 usec_rem
= do_div(t
, USEC_PER_SEC
);
5299 trace_seq_printf(s
, "oldest event ts: %5llu.%06lu\n",
5302 t
= ns2usecs(ring_buffer_time_stamp(trace_buf
->buffer
, cpu
));
5303 usec_rem
= do_div(t
, USEC_PER_SEC
);
5304 trace_seq_printf(s
, "now ts: %5llu.%06lu\n", t
, usec_rem
);
5306 /* counter or tsc mode for trace_clock */
5307 trace_seq_printf(s
, "oldest event ts: %llu\n",
5308 ring_buffer_oldest_event_ts(trace_buf
->buffer
, cpu
));
5310 trace_seq_printf(s
, "now ts: %llu\n",
5311 ring_buffer_time_stamp(trace_buf
->buffer
, cpu
));
5314 cnt
= ring_buffer_dropped_events_cpu(trace_buf
->buffer
, cpu
);
5315 trace_seq_printf(s
, "dropped events: %ld\n", cnt
);
5317 cnt
= ring_buffer_read_events_cpu(trace_buf
->buffer
, cpu
);
5318 trace_seq_printf(s
, "read events: %ld\n", cnt
);
5320 count
= simple_read_from_buffer(ubuf
, count
, ppos
, s
->buffer
, s
->len
);
5327 static const struct file_operations tracing_stats_fops
= {
5328 .open
= tracing_open_generic_tr
,
5329 .read
= tracing_stats_read
,
5330 .llseek
= generic_file_llseek
,
5331 .release
= tracing_release_generic_tr
,
5334 #ifdef CONFIG_DYNAMIC_FTRACE
5336 int __weak
ftrace_arch_read_dyn_info(char *buf
, int size
)
5342 tracing_read_dyn_info(struct file
*filp
, char __user
*ubuf
,
5343 size_t cnt
, loff_t
*ppos
)
5345 static char ftrace_dyn_info_buffer
[1024];
5346 static DEFINE_MUTEX(dyn_info_mutex
);
5347 unsigned long *p
= filp
->private_data
;
5348 char *buf
= ftrace_dyn_info_buffer
;
5349 int size
= ARRAY_SIZE(ftrace_dyn_info_buffer
);
5352 mutex_lock(&dyn_info_mutex
);
5353 r
= sprintf(buf
, "%ld ", *p
);
5355 r
+= ftrace_arch_read_dyn_info(buf
+r
, (size
-1)-r
);
5358 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
5360 mutex_unlock(&dyn_info_mutex
);
5365 static const struct file_operations tracing_dyn_info_fops
= {
5366 .open
= tracing_open_generic
,
5367 .read
= tracing_read_dyn_info
,
5368 .llseek
= generic_file_llseek
,
5370 #endif /* CONFIG_DYNAMIC_FTRACE */
5372 #if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
5374 ftrace_snapshot(unsigned long ip
, unsigned long parent_ip
, void **data
)
5380 ftrace_count_snapshot(unsigned long ip
, unsigned long parent_ip
, void **data
)
5382 unsigned long *count
= (long *)data
;
5394 ftrace_snapshot_print(struct seq_file
*m
, unsigned long ip
,
5395 struct ftrace_probe_ops
*ops
, void *data
)
5397 long count
= (long)data
;
5399 seq_printf(m
, "%ps:", (void *)ip
);
5401 seq_printf(m
, "snapshot");
5404 seq_printf(m
, ":unlimited\n");
5406 seq_printf(m
, ":count=%ld\n", count
);
5411 static struct ftrace_probe_ops snapshot_probe_ops
= {
5412 .func
= ftrace_snapshot
,
5413 .print
= ftrace_snapshot_print
,
5416 static struct ftrace_probe_ops snapshot_count_probe_ops
= {
5417 .func
= ftrace_count_snapshot
,
5418 .print
= ftrace_snapshot_print
,
5422 ftrace_trace_snapshot_callback(struct ftrace_hash
*hash
,
5423 char *glob
, char *cmd
, char *param
, int enable
)
5425 struct ftrace_probe_ops
*ops
;
5426 void *count
= (void *)-1;
5430 /* hash funcs only work with set_ftrace_filter */
5434 ops
= param
? &snapshot_count_probe_ops
: &snapshot_probe_ops
;
5436 if (glob
[0] == '!') {
5437 unregister_ftrace_function_probe_func(glob
+1, ops
);
5444 number
= strsep(¶m
, ":");
5446 if (!strlen(number
))
5450 * We use the callback data field (which is a pointer)
5453 ret
= kstrtoul(number
, 0, (unsigned long *)&count
);
5458 ret
= register_ftrace_function_probe(glob
, ops
, count
);
5461 alloc_snapshot(&global_trace
);
5463 return ret
< 0 ? ret
: 0;
5466 static struct ftrace_func_command ftrace_snapshot_cmd
= {
5468 .func
= ftrace_trace_snapshot_callback
,
5471 static __init
int register_snapshot_cmd(void)
5473 return register_ftrace_command(&ftrace_snapshot_cmd
);
5476 static inline __init
int register_snapshot_cmd(void) { return 0; }
5477 #endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
5479 struct dentry
*tracing_init_dentry_tr(struct trace_array
*tr
)
5484 if (!debugfs_initialized())
5487 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
5488 tr
->dir
= debugfs_create_dir("tracing", NULL
);
5491 pr_warn_once("Could not create debugfs directory 'tracing'\n");
5496 struct dentry
*tracing_init_dentry(void)
5498 return tracing_init_dentry_tr(&global_trace
);
5501 static struct dentry
*tracing_dentry_percpu(struct trace_array
*tr
, int cpu
)
5503 struct dentry
*d_tracer
;
5506 return tr
->percpu_dir
;
5508 d_tracer
= tracing_init_dentry_tr(tr
);
5512 tr
->percpu_dir
= debugfs_create_dir("per_cpu", d_tracer
);
5514 WARN_ONCE(!tr
->percpu_dir
,
5515 "Could not create debugfs directory 'per_cpu/%d'\n", cpu
);
5517 return tr
->percpu_dir
;
5520 static struct dentry
*
5521 trace_create_cpu_file(const char *name
, umode_t mode
, struct dentry
*parent
,
5522 void *data
, long cpu
, const struct file_operations
*fops
)
5524 struct dentry
*ret
= trace_create_file(name
, mode
, parent
, data
, fops
);
5526 if (ret
) /* See tracing_get_cpu() */
5527 ret
->d_inode
->i_cdev
= (void *)(cpu
+ 1);
5532 tracing_init_debugfs_percpu(struct trace_array
*tr
, long cpu
)
5534 struct dentry
*d_percpu
= tracing_dentry_percpu(tr
, cpu
);
5535 struct dentry
*d_cpu
;
5536 char cpu_dir
[30]; /* 30 characters should be more than enough */
5541 snprintf(cpu_dir
, 30, "cpu%ld", cpu
);
5542 d_cpu
= debugfs_create_dir(cpu_dir
, d_percpu
);
5544 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir
);
5548 /* per cpu trace_pipe */
5549 trace_create_cpu_file("trace_pipe", 0444, d_cpu
,
5550 tr
, cpu
, &tracing_pipe_fops
);
5553 trace_create_cpu_file("trace", 0644, d_cpu
,
5554 tr
, cpu
, &tracing_fops
);
5556 trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu
,
5557 tr
, cpu
, &tracing_buffers_fops
);
5559 trace_create_cpu_file("stats", 0444, d_cpu
,
5560 tr
, cpu
, &tracing_stats_fops
);
5562 trace_create_cpu_file("buffer_size_kb", 0444, d_cpu
,
5563 tr
, cpu
, &tracing_entries_fops
);
5565 #ifdef CONFIG_TRACER_SNAPSHOT
5566 trace_create_cpu_file("snapshot", 0644, d_cpu
,
5567 tr
, cpu
, &snapshot_fops
);
5569 trace_create_cpu_file("snapshot_raw", 0444, d_cpu
,
5570 tr
, cpu
, &snapshot_raw_fops
);
5574 #ifdef CONFIG_FTRACE_SELFTEST
5575 /* Let selftest have access to static functions in this file */
5576 #include "trace_selftest.c"
5579 struct trace_option_dentry
{
5580 struct tracer_opt
*opt
;
5581 struct tracer_flags
*flags
;
5582 struct trace_array
*tr
;
5583 struct dentry
*entry
;
5587 trace_options_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
5590 struct trace_option_dentry
*topt
= filp
->private_data
;
5593 if (topt
->flags
->val
& topt
->opt
->bit
)
5598 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
5602 trace_options_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
5605 struct trace_option_dentry
*topt
= filp
->private_data
;
5609 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5613 if (val
!= 0 && val
!= 1)
5616 if (!!(topt
->flags
->val
& topt
->opt
->bit
) != val
) {
5617 mutex_lock(&trace_types_lock
);
5618 ret
= __set_tracer_option(topt
->tr
->current_trace
, topt
->flags
,
5620 mutex_unlock(&trace_types_lock
);
5631 static const struct file_operations trace_options_fops
= {
5632 .open
= tracing_open_generic
,
5633 .read
= trace_options_read
,
5634 .write
= trace_options_write
,
5635 .llseek
= generic_file_llseek
,
5639 trace_options_core_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
5642 long index
= (long)filp
->private_data
;
5645 if (trace_flags
& (1 << index
))
5650 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
5654 trace_options_core_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
5657 struct trace_array
*tr
= &global_trace
;
5658 long index
= (long)filp
->private_data
;
5662 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5666 if (val
!= 0 && val
!= 1)
5669 mutex_lock(&trace_types_lock
);
5670 ret
= set_tracer_flag(tr
, 1 << index
, val
);
5671 mutex_unlock(&trace_types_lock
);
5681 static const struct file_operations trace_options_core_fops
= {
5682 .open
= tracing_open_generic
,
5683 .read
= trace_options_core_read
,
5684 .write
= trace_options_core_write
,
5685 .llseek
= generic_file_llseek
,
5688 struct dentry
*trace_create_file(const char *name
,
5690 struct dentry
*parent
,
5692 const struct file_operations
*fops
)
5696 ret
= debugfs_create_file(name
, mode
, parent
, data
, fops
);
5698 pr_warning("Could not create debugfs '%s' entry\n", name
);
5704 static struct dentry
*trace_options_init_dentry(struct trace_array
*tr
)
5706 struct dentry
*d_tracer
;
5711 d_tracer
= tracing_init_dentry_tr(tr
);
5715 tr
->options
= debugfs_create_dir("options", d_tracer
);
5717 pr_warning("Could not create debugfs directory 'options'\n");
5725 create_trace_option_file(struct trace_array
*tr
,
5726 struct trace_option_dentry
*topt
,
5727 struct tracer_flags
*flags
,
5728 struct tracer_opt
*opt
)
5730 struct dentry
*t_options
;
5732 t_options
= trace_options_init_dentry(tr
);
5736 topt
->flags
= flags
;
5740 topt
->entry
= trace_create_file(opt
->name
, 0644, t_options
, topt
,
5741 &trace_options_fops
);
5745 static struct trace_option_dentry
*
5746 create_trace_option_files(struct trace_array
*tr
, struct tracer
*tracer
)
5748 struct trace_option_dentry
*topts
;
5749 struct tracer_flags
*flags
;
5750 struct tracer_opt
*opts
;
5756 flags
= tracer
->flags
;
5758 if (!flags
|| !flags
->opts
)
5763 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
5766 topts
= kcalloc(cnt
+ 1, sizeof(*topts
), GFP_KERNEL
);
5770 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
5771 create_trace_option_file(tr
, &topts
[cnt
], flags
,
5778 destroy_trace_option_files(struct trace_option_dentry
*topts
)
5785 for (cnt
= 0; topts
[cnt
].opt
; cnt
++) {
5786 if (topts
[cnt
].entry
)
5787 debugfs_remove(topts
[cnt
].entry
);
5793 static struct dentry
*
5794 create_trace_option_core_file(struct trace_array
*tr
,
5795 const char *option
, long index
)
5797 struct dentry
*t_options
;
5799 t_options
= trace_options_init_dentry(tr
);
5803 return trace_create_file(option
, 0644, t_options
, (void *)index
,
5804 &trace_options_core_fops
);
5807 static __init
void create_trace_options_dir(struct trace_array
*tr
)
5809 struct dentry
*t_options
;
5812 t_options
= trace_options_init_dentry(tr
);
5816 for (i
= 0; trace_options
[i
]; i
++)
5817 create_trace_option_core_file(tr
, trace_options
[i
], i
);
5821 rb_simple_read(struct file
*filp
, char __user
*ubuf
,
5822 size_t cnt
, loff_t
*ppos
)
5824 struct trace_array
*tr
= filp
->private_data
;
5828 r
= tracer_tracing_is_on(tr
);
5829 r
= sprintf(buf
, "%d\n", r
);
5831 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
5835 rb_simple_write(struct file
*filp
, const char __user
*ubuf
,
5836 size_t cnt
, loff_t
*ppos
)
5838 struct trace_array
*tr
= filp
->private_data
;
5839 struct ring_buffer
*buffer
= tr
->trace_buffer
.buffer
;
5843 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5848 mutex_lock(&trace_types_lock
);
5850 tracer_tracing_on(tr
);
5851 if (tr
->current_trace
->start
)
5852 tr
->current_trace
->start(tr
);
5854 tracer_tracing_off(tr
);
5855 if (tr
->current_trace
->stop
)
5856 tr
->current_trace
->stop(tr
);
5858 mutex_unlock(&trace_types_lock
);
5866 static const struct file_operations rb_simple_fops
= {
5867 .open
= tracing_open_generic_tr
,
5868 .read
= rb_simple_read
,
5869 .write
= rb_simple_write
,
5870 .release
= tracing_release_generic_tr
,
5871 .llseek
= default_llseek
,
5874 struct dentry
*trace_instance_dir
;
5877 init_tracer_debugfs(struct trace_array
*tr
, struct dentry
*d_tracer
);
5880 allocate_trace_buffer(struct trace_array
*tr
, struct trace_buffer
*buf
, int size
)
5882 enum ring_buffer_flags rb_flags
;
5884 rb_flags
= trace_flags
& TRACE_ITER_OVERWRITE
? RB_FL_OVERWRITE
: 0;
5886 buf
->buffer
= ring_buffer_alloc(size
, rb_flags
);
5890 buf
->data
= alloc_percpu(struct trace_array_cpu
);
5892 ring_buffer_free(buf
->buffer
);
5896 /* Allocate the first page for all buffers */
5897 set_buffer_entries(&tr
->trace_buffer
,
5898 ring_buffer_size(tr
->trace_buffer
.buffer
, 0));
5903 static int allocate_trace_buffers(struct trace_array
*tr
, int size
)
5907 ret
= allocate_trace_buffer(tr
, &tr
->trace_buffer
, size
);
5911 #ifdef CONFIG_TRACER_MAX_TRACE
5912 ret
= allocate_trace_buffer(tr
, &tr
->max_buffer
,
5913 allocate_snapshot
? size
: 1);
5915 ring_buffer_free(tr
->trace_buffer
.buffer
);
5916 free_percpu(tr
->trace_buffer
.data
);
5919 tr
->allocated_snapshot
= allocate_snapshot
;
5922 * Only the top level trace array gets its snapshot allocated
5923 * from the kernel command line.
5925 allocate_snapshot
= false;
5930 static int new_instance_create(const char *name
)
5932 struct trace_array
*tr
;
5935 mutex_lock(&trace_types_lock
);
5938 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
5939 if (tr
->name
&& strcmp(tr
->name
, name
) == 0)
5944 tr
= kzalloc(sizeof(*tr
), GFP_KERNEL
);
5948 tr
->name
= kstrdup(name
, GFP_KERNEL
);
5952 if (!alloc_cpumask_var(&tr
->tracing_cpumask
, GFP_KERNEL
))
5955 cpumask_copy(tr
->tracing_cpumask
, cpu_all_mask
);
5957 raw_spin_lock_init(&tr
->start_lock
);
5959 tr
->current_trace
= &nop_trace
;
5961 INIT_LIST_HEAD(&tr
->systems
);
5962 INIT_LIST_HEAD(&tr
->events
);
5964 if (allocate_trace_buffers(tr
, trace_buf_size
) < 0)
5967 tr
->dir
= debugfs_create_dir(name
, trace_instance_dir
);
5971 ret
= event_trace_add_tracer(tr
->dir
, tr
);
5973 debugfs_remove_recursive(tr
->dir
);
5977 init_tracer_debugfs(tr
, tr
->dir
);
5979 list_add(&tr
->list
, &ftrace_trace_arrays
);
5981 mutex_unlock(&trace_types_lock
);
5986 if (tr
->trace_buffer
.buffer
)
5987 ring_buffer_free(tr
->trace_buffer
.buffer
);
5988 free_cpumask_var(tr
->tracing_cpumask
);
5993 mutex_unlock(&trace_types_lock
);
5999 static int instance_delete(const char *name
)
6001 struct trace_array
*tr
;
6005 mutex_lock(&trace_types_lock
);
6008 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
6009 if (tr
->name
&& strcmp(tr
->name
, name
) == 0) {
6021 list_del(&tr
->list
);
6023 event_trace_del_tracer(tr
);
6024 debugfs_remove_recursive(tr
->dir
);
6025 free_percpu(tr
->trace_buffer
.data
);
6026 ring_buffer_free(tr
->trace_buffer
.buffer
);
6034 mutex_unlock(&trace_types_lock
);
6039 static int instance_mkdir (struct inode
*inode
, struct dentry
*dentry
, umode_t mode
)
6041 struct dentry
*parent
;
6044 /* Paranoid: Make sure the parent is the "instances" directory */
6045 parent
= hlist_entry(inode
->i_dentry
.first
, struct dentry
, d_alias
);
6046 if (WARN_ON_ONCE(parent
!= trace_instance_dir
))
6050 * The inode mutex is locked, but debugfs_create_dir() will also
6051 * take the mutex. As the instances directory can not be destroyed
6052 * or changed in any other way, it is safe to unlock it, and
6053 * let the dentry try. If two users try to make the same dir at
6054 * the same time, then the new_instance_create() will determine the
6057 mutex_unlock(&inode
->i_mutex
);
6059 ret
= new_instance_create(dentry
->d_iname
);
6061 mutex_lock(&inode
->i_mutex
);
6066 static int instance_rmdir(struct inode
*inode
, struct dentry
*dentry
)
6068 struct dentry
*parent
;
6071 /* Paranoid: Make sure the parent is the "instances" directory */
6072 parent
= hlist_entry(inode
->i_dentry
.first
, struct dentry
, d_alias
);
6073 if (WARN_ON_ONCE(parent
!= trace_instance_dir
))
6076 /* The caller did a dget() on dentry */
6077 mutex_unlock(&dentry
->d_inode
->i_mutex
);
6080 * The inode mutex is locked, but debugfs_create_dir() will also
6081 * take the mutex. As the instances directory can not be destroyed
6082 * or changed in any other way, it is safe to unlock it, and
6083 * let the dentry try. If two users try to make the same dir at
6084 * the same time, then the instance_delete() will determine the
6087 mutex_unlock(&inode
->i_mutex
);
6089 ret
= instance_delete(dentry
->d_iname
);
6091 mutex_lock_nested(&inode
->i_mutex
, I_MUTEX_PARENT
);
6092 mutex_lock(&dentry
->d_inode
->i_mutex
);
6097 static const struct inode_operations instance_dir_inode_operations
= {
6098 .lookup
= simple_lookup
,
6099 .mkdir
= instance_mkdir
,
6100 .rmdir
= instance_rmdir
,
6103 static __init
void create_trace_instances(struct dentry
*d_tracer
)
6105 trace_instance_dir
= debugfs_create_dir("instances", d_tracer
);
6106 if (WARN_ON(!trace_instance_dir
))
6109 /* Hijack the dir inode operations, to allow mkdir */
6110 trace_instance_dir
->d_inode
->i_op
= &instance_dir_inode_operations
;
6114 init_tracer_debugfs(struct trace_array
*tr
, struct dentry
*d_tracer
)
6118 trace_create_file("tracing_cpumask", 0644, d_tracer
,
6119 tr
, &tracing_cpumask_fops
);
6121 trace_create_file("trace_options", 0644, d_tracer
,
6122 tr
, &tracing_iter_fops
);
6124 trace_create_file("trace", 0644, d_tracer
,
6127 trace_create_file("trace_pipe", 0444, d_tracer
,
6128 tr
, &tracing_pipe_fops
);
6130 trace_create_file("buffer_size_kb", 0644, d_tracer
,
6131 tr
, &tracing_entries_fops
);
6133 trace_create_file("buffer_total_size_kb", 0444, d_tracer
,
6134 tr
, &tracing_total_entries_fops
);
6136 trace_create_file("free_buffer", 0200, d_tracer
,
6137 tr
, &tracing_free_buffer_fops
);
6139 trace_create_file("trace_marker", 0220, d_tracer
,
6140 tr
, &tracing_mark_fops
);
6142 trace_create_file("trace_clock", 0644, d_tracer
, tr
,
6145 trace_create_file("tracing_on", 0644, d_tracer
,
6146 tr
, &rb_simple_fops
);
6148 #ifdef CONFIG_TRACER_SNAPSHOT
6149 trace_create_file("snapshot", 0644, d_tracer
,
6150 tr
, &snapshot_fops
);
6153 for_each_tracing_cpu(cpu
)
6154 tracing_init_debugfs_percpu(tr
, cpu
);
6158 static __init
int tracer_init_debugfs(void)
6160 struct dentry
*d_tracer
;
6162 trace_access_lock_init();
6164 d_tracer
= tracing_init_dentry();
6168 init_tracer_debugfs(&global_trace
, d_tracer
);
6170 trace_create_file("available_tracers", 0444, d_tracer
,
6171 &global_trace
, &show_traces_fops
);
6173 trace_create_file("current_tracer", 0644, d_tracer
,
6174 &global_trace
, &set_tracer_fops
);
6176 #ifdef CONFIG_TRACER_MAX_TRACE
6177 trace_create_file("tracing_max_latency", 0644, d_tracer
,
6178 &tracing_max_latency
, &tracing_max_lat_fops
);
6181 trace_create_file("tracing_thresh", 0644, d_tracer
,
6182 &tracing_thresh
, &tracing_max_lat_fops
);
6184 trace_create_file("README", 0444, d_tracer
,
6185 NULL
, &tracing_readme_fops
);
6187 trace_create_file("saved_cmdlines", 0444, d_tracer
,
6188 NULL
, &tracing_saved_cmdlines_fops
);
6190 #ifdef CONFIG_DYNAMIC_FTRACE
6191 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
6192 &ftrace_update_tot_cnt
, &tracing_dyn_info_fops
);
6195 create_trace_instances(d_tracer
);
6197 create_trace_options_dir(&global_trace
);
6202 static int trace_panic_handler(struct notifier_block
*this,
6203 unsigned long event
, void *unused
)
6205 if (ftrace_dump_on_oops
)
6206 ftrace_dump(ftrace_dump_on_oops
);
6210 static struct notifier_block trace_panic_notifier
= {
6211 .notifier_call
= trace_panic_handler
,
6213 .priority
= 150 /* priority: INT_MAX >= x >= 0 */
6216 static int trace_die_handler(struct notifier_block
*self
,
6222 if (ftrace_dump_on_oops
)
6223 ftrace_dump(ftrace_dump_on_oops
);
6231 static struct notifier_block trace_die_notifier
= {
6232 .notifier_call
= trace_die_handler
,
6237 * printk is set to max of 1024, we really don't need it that big.
6238 * Nothing should be printing 1000 characters anyway.
6240 #define TRACE_MAX_PRINT 1000
6243 * Define here KERN_TRACE so that we have one place to modify
6244 * it if we decide to change what log level the ftrace dump
6247 #define KERN_TRACE KERN_EMERG
6250 trace_printk_seq(struct trace_seq
*s
)
6252 /* Probably should print a warning here. */
6253 if (s
->len
>= TRACE_MAX_PRINT
)
6254 s
->len
= TRACE_MAX_PRINT
;
6256 /* should be zero ended, but we are paranoid. */
6257 s
->buffer
[s
->len
] = 0;
6259 printk(KERN_TRACE
"%s", s
->buffer
);
6264 void trace_init_global_iter(struct trace_iterator
*iter
)
6266 iter
->tr
= &global_trace
;
6267 iter
->trace
= iter
->tr
->current_trace
;
6268 iter
->cpu_file
= RING_BUFFER_ALL_CPUS
;
6269 iter
->trace_buffer
= &global_trace
.trace_buffer
;
6271 if (iter
->trace
&& iter
->trace
->open
)
6272 iter
->trace
->open(iter
);
6274 /* Annotate start of buffers if we had overruns */
6275 if (ring_buffer_overruns(iter
->trace_buffer
->buffer
))
6276 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
6278 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
6279 if (trace_clocks
[iter
->tr
->clock_id
].in_ns
)
6280 iter
->iter_flags
|= TRACE_FILE_TIME_IN_NS
;
6283 void ftrace_dump(enum ftrace_dump_mode oops_dump_mode
)
6285 /* use static because iter can be a bit big for the stack */
6286 static struct trace_iterator iter
;
6287 static atomic_t dump_running
;
6288 unsigned int old_userobj
;
6289 unsigned long flags
;
6292 /* Only allow one dump user at a time. */
6293 if (atomic_inc_return(&dump_running
) != 1) {
6294 atomic_dec(&dump_running
);
6299 * Always turn off tracing when we dump.
6300 * We don't need to show trace output of what happens
6301 * between multiple crashes.
6303 * If the user does a sysrq-z, then they can re-enable
6304 * tracing with echo 1 > tracing_on.
6308 local_irq_save(flags
);
6310 /* Simulate the iterator */
6311 trace_init_global_iter(&iter
);
6313 for_each_tracing_cpu(cpu
) {
6314 atomic_inc(&per_cpu_ptr(iter
.tr
->trace_buffer
.data
, cpu
)->disabled
);
6317 old_userobj
= trace_flags
& TRACE_ITER_SYM_USEROBJ
;
6319 /* don't look at user memory in panic mode */
6320 trace_flags
&= ~TRACE_ITER_SYM_USEROBJ
;
6322 switch (oops_dump_mode
) {
6324 iter
.cpu_file
= RING_BUFFER_ALL_CPUS
;
6327 iter
.cpu_file
= raw_smp_processor_id();
6332 printk(KERN_TRACE
"Bad dumping mode, switching to all CPUs dump\n");
6333 iter
.cpu_file
= RING_BUFFER_ALL_CPUS
;
6336 printk(KERN_TRACE
"Dumping ftrace buffer:\n");
6338 /* Did function tracer already get disabled? */
6339 if (ftrace_is_dead()) {
6340 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
6341 printk("# MAY BE MISSING FUNCTION EVENTS\n");
6345 * We need to stop all tracing on all CPUS to read the
6346 * the next buffer. This is a bit expensive, but is
6347 * not done often. We fill all what we can read,
6348 * and then release the locks again.
6351 while (!trace_empty(&iter
)) {
6354 printk(KERN_TRACE
"---------------------------------\n");
6358 /* reset all but tr, trace, and overruns */
6359 memset(&iter
.seq
, 0,
6360 sizeof(struct trace_iterator
) -
6361 offsetof(struct trace_iterator
, seq
));
6362 iter
.iter_flags
|= TRACE_FILE_LAT_FMT
;
6365 if (trace_find_next_entry_inc(&iter
) != NULL
) {
6368 ret
= print_trace_line(&iter
);
6369 if (ret
!= TRACE_TYPE_NO_CONSUME
)
6370 trace_consume(&iter
);
6372 touch_nmi_watchdog();
6374 trace_printk_seq(&iter
.seq
);
6378 printk(KERN_TRACE
" (ftrace buffer empty)\n");
6380 printk(KERN_TRACE
"---------------------------------\n");
6383 trace_flags
|= old_userobj
;
6385 for_each_tracing_cpu(cpu
) {
6386 atomic_dec(&per_cpu_ptr(iter
.trace_buffer
->data
, cpu
)->disabled
);
6388 atomic_dec(&dump_running
);
6389 local_irq_restore(flags
);
6391 EXPORT_SYMBOL_GPL(ftrace_dump
);
6393 __init
static int tracer_alloc_buffers(void)
6399 if (!alloc_cpumask_var(&tracing_buffer_mask
, GFP_KERNEL
))
6402 if (!alloc_cpumask_var(&global_trace
.tracing_cpumask
, GFP_KERNEL
))
6403 goto out_free_buffer_mask
;
6405 /* Only allocate trace_printk buffers if a trace_printk exists */
6406 if (__stop___trace_bprintk_fmt
!= __start___trace_bprintk_fmt
)
6407 /* Must be called before global_trace.buffer is allocated */
6408 trace_printk_init_buffers();
6410 /* To save memory, keep the ring buffer size to its minimum */
6411 if (ring_buffer_expanded
)
6412 ring_buf_size
= trace_buf_size
;
6416 cpumask_copy(tracing_buffer_mask
, cpu_possible_mask
);
6417 cpumask_copy(global_trace
.tracing_cpumask
, cpu_all_mask
);
6419 raw_spin_lock_init(&global_trace
.start_lock
);
6421 /* TODO: make the number of buffers hot pluggable with CPUS */
6422 if (allocate_trace_buffers(&global_trace
, ring_buf_size
) < 0) {
6423 printk(KERN_ERR
"tracer: failed to allocate ring buffer!\n");
6425 goto out_free_cpumask
;
6428 if (global_trace
.buffer_disabled
)
6431 trace_init_cmdlines();
6434 * register_tracer() might reference current_trace, so it
6435 * needs to be set before we register anything. This is
6436 * just a bootstrap of current_trace anyway.
6438 global_trace
.current_trace
= &nop_trace
;
6440 register_tracer(&nop_trace
);
6442 /* All seems OK, enable tracing */
6443 tracing_disabled
= 0;
6445 atomic_notifier_chain_register(&panic_notifier_list
,
6446 &trace_panic_notifier
);
6448 register_die_notifier(&trace_die_notifier
);
6450 global_trace
.flags
= TRACE_ARRAY_FL_GLOBAL
;
6452 INIT_LIST_HEAD(&global_trace
.systems
);
6453 INIT_LIST_HEAD(&global_trace
.events
);
6454 list_add(&global_trace
.list
, &ftrace_trace_arrays
);
6456 while (trace_boot_options
) {
6459 option
= strsep(&trace_boot_options
, ",");
6460 trace_set_options(&global_trace
, option
);
6463 register_snapshot_cmd();
6468 free_percpu(global_trace
.trace_buffer
.data
);
6469 #ifdef CONFIG_TRACER_MAX_TRACE
6470 free_percpu(global_trace
.max_buffer
.data
);
6472 free_cpumask_var(global_trace
.tracing_cpumask
);
6473 out_free_buffer_mask
:
6474 free_cpumask_var(tracing_buffer_mask
);
6479 __init
static int clear_boot_tracer(void)
6482 * The default tracer at boot buffer is an init section.
6483 * This function is called in lateinit. If we did not
6484 * find the boot tracer, then clear it out, to prevent
6485 * later registration from accessing the buffer that is
6486 * about to be freed.
6488 if (!default_bootup_tracer
)
6491 printk(KERN_INFO
"ftrace bootup tracer '%s' not registered.\n",
6492 default_bootup_tracer
);
6493 default_bootup_tracer
= NULL
;
6498 early_initcall(tracer_alloc_buffers
);
6499 fs_initcall(tracer_init_debugfs
);
6500 late_initcall(clear_boot_tracer
);