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_current_check_discard(struct ring_buffer
*buffer
,
239 struct ftrace_event_call
*call
, void *rec
,
240 struct ring_buffer_event
*event
)
242 return filter_check_discard(call
, rec
, buffer
, event
);
244 EXPORT_SYMBOL_GPL(filter_current_check_discard
);
246 cycle_t
ftrace_now(int cpu
)
250 /* Early boot up does not have a buffer yet */
251 if (!global_trace
.trace_buffer
.buffer
)
252 return trace_clock_local();
254 ts
= ring_buffer_time_stamp(global_trace
.trace_buffer
.buffer
, cpu
);
255 ring_buffer_normalize_time_stamp(global_trace
.trace_buffer
.buffer
, cpu
, &ts
);
261 * tracing_is_enabled - Show if global_trace has been disabled
263 * Shows if the global trace has been enabled or not. It uses the
264 * mirror flag "buffer_disabled" to be used in fast paths such as for
265 * the irqsoff tracer. But it may be inaccurate due to races. If you
266 * need to know the accurate state, use tracing_is_on() which is a little
267 * slower, but accurate.
269 int tracing_is_enabled(void)
272 * For quick access (irqsoff uses this in fast path), just
273 * return the mirror variable of the state of the ring buffer.
274 * It's a little racy, but we don't really care.
277 return !global_trace
.buffer_disabled
;
281 * trace_buf_size is the size in bytes that is allocated
282 * for a buffer. Note, the number of bytes is always rounded
285 * This number is purposely set to a low number of 16384.
286 * If the dump on oops happens, it will be much appreciated
287 * to not have to wait for all that output. Anyway this can be
288 * boot time and run time configurable.
290 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
292 static unsigned long trace_buf_size
= TRACE_BUF_SIZE_DEFAULT
;
294 /* trace_types holds a link list of available tracers. */
295 static struct tracer
*trace_types __read_mostly
;
298 * trace_types_lock is used to protect the trace_types list.
300 DEFINE_MUTEX(trace_types_lock
);
303 * serialize the access of the ring buffer
305 * ring buffer serializes readers, but it is low level protection.
306 * The validity of the events (which returns by ring_buffer_peek() ..etc)
307 * are not protected by ring buffer.
309 * The content of events may become garbage if we allow other process consumes
310 * these events concurrently:
311 * A) the page of the consumed events may become a normal page
312 * (not reader page) in ring buffer, and this page will be rewrited
313 * by events producer.
314 * B) The page of the consumed events may become a page for splice_read,
315 * and this page will be returned to system.
317 * These primitives allow multi process access to different cpu ring buffer
320 * These primitives don't distinguish read-only and read-consume access.
321 * Multi read-only access are also serialized.
325 static DECLARE_RWSEM(all_cpu_access_lock
);
326 static DEFINE_PER_CPU(struct mutex
, cpu_access_lock
);
328 static inline void trace_access_lock(int cpu
)
330 if (cpu
== RING_BUFFER_ALL_CPUS
) {
331 /* gain it for accessing the whole ring buffer. */
332 down_write(&all_cpu_access_lock
);
334 /* gain it for accessing a cpu ring buffer. */
336 /* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
337 down_read(&all_cpu_access_lock
);
339 /* Secondly block other access to this @cpu ring buffer. */
340 mutex_lock(&per_cpu(cpu_access_lock
, cpu
));
344 static inline void trace_access_unlock(int cpu
)
346 if (cpu
== RING_BUFFER_ALL_CPUS
) {
347 up_write(&all_cpu_access_lock
);
349 mutex_unlock(&per_cpu(cpu_access_lock
, cpu
));
350 up_read(&all_cpu_access_lock
);
354 static inline void trace_access_lock_init(void)
358 for_each_possible_cpu(cpu
)
359 mutex_init(&per_cpu(cpu_access_lock
, cpu
));
364 static DEFINE_MUTEX(access_lock
);
366 static inline void trace_access_lock(int cpu
)
369 mutex_lock(&access_lock
);
372 static inline void trace_access_unlock(int cpu
)
375 mutex_unlock(&access_lock
);
378 static inline void trace_access_lock_init(void)
384 /* trace_flags holds trace_options default values */
385 unsigned long trace_flags
= TRACE_ITER_PRINT_PARENT
| TRACE_ITER_PRINTK
|
386 TRACE_ITER_ANNOTATE
| TRACE_ITER_CONTEXT_INFO
| TRACE_ITER_SLEEP_TIME
|
387 TRACE_ITER_GRAPH_TIME
| TRACE_ITER_RECORD_CMD
| TRACE_ITER_OVERWRITE
|
388 TRACE_ITER_IRQ_INFO
| TRACE_ITER_MARKERS
| TRACE_ITER_FUNCTION
;
390 static void tracer_tracing_on(struct trace_array
*tr
)
392 if (tr
->trace_buffer
.buffer
)
393 ring_buffer_record_on(tr
->trace_buffer
.buffer
);
395 * This flag is looked at when buffers haven't been allocated
396 * yet, or by some tracers (like irqsoff), that just want to
397 * know if the ring buffer has been disabled, but it can handle
398 * races of where it gets disabled but we still do a record.
399 * As the check is in the fast path of the tracers, it is more
400 * important to be fast than accurate.
402 tr
->buffer_disabled
= 0;
403 /* Make the flag seen by readers */
408 * tracing_on - enable tracing buffers
410 * This function enables tracing buffers that may have been
411 * disabled with tracing_off.
413 void tracing_on(void)
415 tracer_tracing_on(&global_trace
);
417 EXPORT_SYMBOL_GPL(tracing_on
);
420 * __trace_puts - write a constant string into the trace buffer.
421 * @ip: The address of the caller
422 * @str: The constant string to write
423 * @size: The size of the string.
425 int __trace_puts(unsigned long ip
, const char *str
, int size
)
427 struct ring_buffer_event
*event
;
428 struct ring_buffer
*buffer
;
429 struct print_entry
*entry
;
430 unsigned long irq_flags
;
433 alloc
= sizeof(*entry
) + size
+ 2; /* possible \n added */
435 local_save_flags(irq_flags
);
436 buffer
= global_trace
.trace_buffer
.buffer
;
437 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, alloc
,
438 irq_flags
, preempt_count());
442 entry
= ring_buffer_event_data(event
);
445 memcpy(&entry
->buf
, str
, size
);
447 /* Add a newline if necessary */
448 if (entry
->buf
[size
- 1] != '\n') {
449 entry
->buf
[size
] = '\n';
450 entry
->buf
[size
+ 1] = '\0';
452 entry
->buf
[size
] = '\0';
454 __buffer_unlock_commit(buffer
, event
);
458 EXPORT_SYMBOL_GPL(__trace_puts
);
461 * __trace_bputs - write the pointer to a constant string into trace buffer
462 * @ip: The address of the caller
463 * @str: The constant string to write to the buffer to
465 int __trace_bputs(unsigned long ip
, const char *str
)
467 struct ring_buffer_event
*event
;
468 struct ring_buffer
*buffer
;
469 struct bputs_entry
*entry
;
470 unsigned long irq_flags
;
471 int size
= sizeof(struct bputs_entry
);
473 local_save_flags(irq_flags
);
474 buffer
= global_trace
.trace_buffer
.buffer
;
475 event
= trace_buffer_lock_reserve(buffer
, TRACE_BPUTS
, size
,
476 irq_flags
, preempt_count());
480 entry
= ring_buffer_event_data(event
);
484 __buffer_unlock_commit(buffer
, event
);
488 EXPORT_SYMBOL_GPL(__trace_bputs
);
490 #ifdef CONFIG_TRACER_SNAPSHOT
492 * trace_snapshot - take a snapshot of the current buffer.
494 * This causes a swap between the snapshot buffer and the current live
495 * tracing buffer. You can use this to take snapshots of the live
496 * trace when some condition is triggered, but continue to trace.
498 * Note, make sure to allocate the snapshot with either
499 * a tracing_snapshot_alloc(), or by doing it manually
500 * with: echo 1 > /sys/kernel/debug/tracing/snapshot
502 * If the snapshot buffer is not allocated, it will stop tracing.
503 * Basically making a permanent snapshot.
505 void tracing_snapshot(void)
507 struct trace_array
*tr
= &global_trace
;
508 struct tracer
*tracer
= tr
->current_trace
;
512 internal_trace_puts("*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
513 internal_trace_puts("*** snapshot is being ignored ***\n");
517 if (!tr
->allocated_snapshot
) {
518 internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n");
519 internal_trace_puts("*** stopping trace here! ***\n");
524 /* Note, snapshot can not be used when the tracer uses it */
525 if (tracer
->use_max_tr
) {
526 internal_trace_puts("*** LATENCY TRACER ACTIVE ***\n");
527 internal_trace_puts("*** Can not use snapshot (sorry) ***\n");
531 local_irq_save(flags
);
532 update_max_tr(tr
, current
, smp_processor_id());
533 local_irq_restore(flags
);
535 EXPORT_SYMBOL_GPL(tracing_snapshot
);
537 static int resize_buffer_duplicate_size(struct trace_buffer
*trace_buf
,
538 struct trace_buffer
*size_buf
, int cpu_id
);
539 static void set_buffer_entries(struct trace_buffer
*buf
, unsigned long val
);
541 static int alloc_snapshot(struct trace_array
*tr
)
545 if (!tr
->allocated_snapshot
) {
547 /* allocate spare buffer */
548 ret
= resize_buffer_duplicate_size(&tr
->max_buffer
,
549 &tr
->trace_buffer
, RING_BUFFER_ALL_CPUS
);
553 tr
->allocated_snapshot
= true;
559 void free_snapshot(struct trace_array
*tr
)
562 * We don't free the ring buffer. instead, resize it because
563 * The max_tr ring buffer has some state (e.g. ring->clock) and
564 * we want preserve it.
566 ring_buffer_resize(tr
->max_buffer
.buffer
, 1, RING_BUFFER_ALL_CPUS
);
567 set_buffer_entries(&tr
->max_buffer
, 1);
568 tracing_reset_online_cpus(&tr
->max_buffer
);
569 tr
->allocated_snapshot
= false;
573 * trace_snapshot_alloc - allocate and take a snapshot of the current buffer.
575 * This is similar to trace_snapshot(), but it will allocate the
576 * snapshot buffer if it isn't already allocated. Use this only
577 * where it is safe to sleep, as the allocation may sleep.
579 * This causes a swap between the snapshot buffer and the current live
580 * tracing buffer. You can use this to take snapshots of the live
581 * trace when some condition is triggered, but continue to trace.
583 void tracing_snapshot_alloc(void)
585 struct trace_array
*tr
= &global_trace
;
588 ret
= alloc_snapshot(tr
);
589 if (WARN_ON(ret
< 0))
594 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc
);
596 void tracing_snapshot(void)
598 WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
600 EXPORT_SYMBOL_GPL(tracing_snapshot
);
601 void tracing_snapshot_alloc(void)
606 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc
);
607 #endif /* CONFIG_TRACER_SNAPSHOT */
609 static void tracer_tracing_off(struct trace_array
*tr
)
611 if (tr
->trace_buffer
.buffer
)
612 ring_buffer_record_off(tr
->trace_buffer
.buffer
);
614 * This flag is looked at when buffers haven't been allocated
615 * yet, or by some tracers (like irqsoff), that just want to
616 * know if the ring buffer has been disabled, but it can handle
617 * races of where it gets disabled but we still do a record.
618 * As the check is in the fast path of the tracers, it is more
619 * important to be fast than accurate.
621 tr
->buffer_disabled
= 1;
622 /* Make the flag seen by readers */
627 * tracing_off - turn off tracing buffers
629 * This function stops the tracing buffers from recording data.
630 * It does not disable any overhead the tracers themselves may
631 * be causing. This function simply causes all recording to
632 * the ring buffers to fail.
634 void tracing_off(void)
636 tracer_tracing_off(&global_trace
);
638 EXPORT_SYMBOL_GPL(tracing_off
);
640 void disable_trace_on_warning(void)
642 if (__disable_trace_on_warning
)
647 * tracer_tracing_is_on - show real state of ring buffer enabled
648 * @tr : the trace array to know if ring buffer is enabled
650 * Shows real state of the ring buffer if it is enabled or not.
652 static int tracer_tracing_is_on(struct trace_array
*tr
)
654 if (tr
->trace_buffer
.buffer
)
655 return ring_buffer_record_is_on(tr
->trace_buffer
.buffer
);
656 return !tr
->buffer_disabled
;
660 * tracing_is_on - show state of ring buffers enabled
662 int tracing_is_on(void)
664 return tracer_tracing_is_on(&global_trace
);
666 EXPORT_SYMBOL_GPL(tracing_is_on
);
668 static int __init
set_buf_size(char *str
)
670 unsigned long buf_size
;
674 buf_size
= memparse(str
, &str
);
675 /* nr_entries can not be zero */
678 trace_buf_size
= buf_size
;
681 __setup("trace_buf_size=", set_buf_size
);
683 static int __init
set_tracing_thresh(char *str
)
685 unsigned long threshold
;
690 ret
= kstrtoul(str
, 0, &threshold
);
693 tracing_thresh
= threshold
* 1000;
696 __setup("tracing_thresh=", set_tracing_thresh
);
698 unsigned long nsecs_to_usecs(unsigned long nsecs
)
703 /* These must match the bit postions in trace_iterator_flags */
704 static const char *trace_options
[] = {
737 int in_ns
; /* is this clock in nanoseconds? */
739 { trace_clock_local
, "local", 1 },
740 { trace_clock_global
, "global", 1 },
741 { trace_clock_counter
, "counter", 0 },
742 { trace_clock_jiffies
, "uptime", 1 },
743 { trace_clock
, "perf", 1 },
748 * trace_parser_get_init - gets the buffer for trace parser
750 int trace_parser_get_init(struct trace_parser
*parser
, int size
)
752 memset(parser
, 0, sizeof(*parser
));
754 parser
->buffer
= kmalloc(size
, GFP_KERNEL
);
763 * trace_parser_put - frees the buffer for trace parser
765 void trace_parser_put(struct trace_parser
*parser
)
767 kfree(parser
->buffer
);
771 * trace_get_user - reads the user input string separated by space
772 * (matched by isspace(ch))
774 * For each string found the 'struct trace_parser' is updated,
775 * and the function returns.
777 * Returns number of bytes read.
779 * See kernel/trace/trace.h for 'struct trace_parser' details.
781 int trace_get_user(struct trace_parser
*parser
, const char __user
*ubuf
,
782 size_t cnt
, loff_t
*ppos
)
789 trace_parser_clear(parser
);
791 ret
= get_user(ch
, ubuf
++);
799 * The parser is not finished with the last write,
800 * continue reading the user input without skipping spaces.
803 /* skip white space */
804 while (cnt
&& isspace(ch
)) {
805 ret
= get_user(ch
, ubuf
++);
812 /* only spaces were written */
822 /* read the non-space input */
823 while (cnt
&& !isspace(ch
)) {
824 if (parser
->idx
< parser
->size
- 1)
825 parser
->buffer
[parser
->idx
++] = ch
;
830 ret
= get_user(ch
, ubuf
++);
837 /* We either got finished input or we have to wait for another call. */
839 parser
->buffer
[parser
->idx
] = 0;
840 parser
->cont
= false;
843 parser
->buffer
[parser
->idx
++] = ch
;
853 ssize_t
trace_seq_to_user(struct trace_seq
*s
, char __user
*ubuf
, size_t cnt
)
861 if (s
->len
<= s
->readpos
)
864 len
= s
->len
- s
->readpos
;
867 ret
= copy_to_user(ubuf
, s
->buffer
+ s
->readpos
, cnt
);
877 static ssize_t
trace_seq_to_buffer(struct trace_seq
*s
, void *buf
, size_t cnt
)
881 if (s
->len
<= s
->readpos
)
884 len
= s
->len
- s
->readpos
;
887 memcpy(buf
, s
->buffer
+ s
->readpos
, cnt
);
894 * ftrace_max_lock is used to protect the swapping of buffers
895 * when taking a max snapshot. The buffers themselves are
896 * protected by per_cpu spinlocks. But the action of the swap
897 * needs its own lock.
899 * This is defined as a arch_spinlock_t in order to help
900 * with performance when lockdep debugging is enabled.
902 * It is also used in other places outside the update_max_tr
903 * so it needs to be defined outside of the
904 * CONFIG_TRACER_MAX_TRACE.
906 static arch_spinlock_t ftrace_max_lock
=
907 (arch_spinlock_t
)__ARCH_SPIN_LOCK_UNLOCKED
;
909 unsigned long __read_mostly tracing_thresh
;
911 #ifdef CONFIG_TRACER_MAX_TRACE
912 unsigned long __read_mostly tracing_max_latency
;
915 * Copy the new maximum trace into the separate maximum-trace
916 * structure. (this way the maximum trace is permanently saved,
917 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
920 __update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
922 struct trace_buffer
*trace_buf
= &tr
->trace_buffer
;
923 struct trace_buffer
*max_buf
= &tr
->max_buffer
;
924 struct trace_array_cpu
*data
= per_cpu_ptr(trace_buf
->data
, cpu
);
925 struct trace_array_cpu
*max_data
= per_cpu_ptr(max_buf
->data
, cpu
);
928 max_buf
->time_start
= data
->preempt_timestamp
;
930 max_data
->saved_latency
= tracing_max_latency
;
931 max_data
->critical_start
= data
->critical_start
;
932 max_data
->critical_end
= data
->critical_end
;
934 memcpy(max_data
->comm
, tsk
->comm
, TASK_COMM_LEN
);
935 max_data
->pid
= tsk
->pid
;
937 * If tsk == current, then use current_uid(), as that does not use
938 * RCU. The irq tracer can be called out of RCU scope.
941 max_data
->uid
= current_uid();
943 max_data
->uid
= task_uid(tsk
);
945 max_data
->nice
= tsk
->static_prio
- 20 - MAX_RT_PRIO
;
946 max_data
->policy
= tsk
->policy
;
947 max_data
->rt_priority
= tsk
->rt_priority
;
949 /* record this tasks comm */
950 tracing_record_cmdline(tsk
);
954 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
956 * @tsk: the task with the latency
957 * @cpu: The cpu that initiated the trace.
959 * Flip the buffers between the @tr and the max_tr and record information
960 * about which task was the cause of this latency.
963 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
965 struct ring_buffer
*buf
;
970 WARN_ON_ONCE(!irqs_disabled());
972 if (!tr
->allocated_snapshot
) {
973 /* Only the nop tracer should hit this when disabling */
974 WARN_ON_ONCE(tr
->current_trace
!= &nop_trace
);
978 arch_spin_lock(&ftrace_max_lock
);
980 buf
= tr
->trace_buffer
.buffer
;
981 tr
->trace_buffer
.buffer
= tr
->max_buffer
.buffer
;
982 tr
->max_buffer
.buffer
= buf
;
984 __update_max_tr(tr
, tsk
, cpu
);
985 arch_spin_unlock(&ftrace_max_lock
);
989 * update_max_tr_single - only copy one trace over, and reset the rest
991 * @tsk - task with the latency
992 * @cpu - the cpu of the buffer to copy.
994 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
997 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
1004 WARN_ON_ONCE(!irqs_disabled());
1005 if (!tr
->allocated_snapshot
) {
1006 /* Only the nop tracer should hit this when disabling */
1007 WARN_ON_ONCE(tr
->current_trace
!= &nop_trace
);
1011 arch_spin_lock(&ftrace_max_lock
);
1013 ret
= ring_buffer_swap_cpu(tr
->max_buffer
.buffer
, tr
->trace_buffer
.buffer
, cpu
);
1015 if (ret
== -EBUSY
) {
1017 * We failed to swap the buffer due to a commit taking
1018 * place on this CPU. We fail to record, but we reset
1019 * the max trace buffer (no one writes directly to it)
1020 * and flag that it failed.
1022 trace_array_printk_buf(tr
->max_buffer
.buffer
, _THIS_IP_
,
1023 "Failed to swap buffers due to commit in progress\n");
1026 WARN_ON_ONCE(ret
&& ret
!= -EAGAIN
&& ret
!= -EBUSY
);
1028 __update_max_tr(tr
, tsk
, cpu
);
1029 arch_spin_unlock(&ftrace_max_lock
);
1031 #endif /* CONFIG_TRACER_MAX_TRACE */
1033 static void default_wait_pipe(struct trace_iterator
*iter
)
1035 /* Iterators are static, they should be filled or empty */
1036 if (trace_buffer_iter(iter
, iter
->cpu_file
))
1039 ring_buffer_wait(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
1042 #ifdef CONFIG_FTRACE_STARTUP_TEST
1043 static int run_tracer_selftest(struct tracer
*type
)
1045 struct trace_array
*tr
= &global_trace
;
1046 struct tracer
*saved_tracer
= tr
->current_trace
;
1049 if (!type
->selftest
|| tracing_selftest_disabled
)
1053 * Run a selftest on this tracer.
1054 * Here we reset the trace buffer, and set the current
1055 * tracer to be this tracer. The tracer can then run some
1056 * internal tracing to verify that everything is in order.
1057 * If we fail, we do not register this tracer.
1059 tracing_reset_online_cpus(&tr
->trace_buffer
);
1061 tr
->current_trace
= type
;
1063 #ifdef CONFIG_TRACER_MAX_TRACE
1064 if (type
->use_max_tr
) {
1065 /* If we expanded the buffers, make sure the max is expanded too */
1066 if (ring_buffer_expanded
)
1067 ring_buffer_resize(tr
->max_buffer
.buffer
, trace_buf_size
,
1068 RING_BUFFER_ALL_CPUS
);
1069 tr
->allocated_snapshot
= true;
1073 /* the test is responsible for initializing and enabling */
1074 pr_info("Testing tracer %s: ", type
->name
);
1075 ret
= type
->selftest(type
, tr
);
1076 /* the test is responsible for resetting too */
1077 tr
->current_trace
= saved_tracer
;
1079 printk(KERN_CONT
"FAILED!\n");
1080 /* Add the warning after printing 'FAILED' */
1084 /* Only reset on passing, to avoid touching corrupted buffers */
1085 tracing_reset_online_cpus(&tr
->trace_buffer
);
1087 #ifdef CONFIG_TRACER_MAX_TRACE
1088 if (type
->use_max_tr
) {
1089 tr
->allocated_snapshot
= false;
1091 /* Shrink the max buffer again */
1092 if (ring_buffer_expanded
)
1093 ring_buffer_resize(tr
->max_buffer
.buffer
, 1,
1094 RING_BUFFER_ALL_CPUS
);
1098 printk(KERN_CONT
"PASSED\n");
1102 static inline int run_tracer_selftest(struct tracer
*type
)
1106 #endif /* CONFIG_FTRACE_STARTUP_TEST */
1109 * register_tracer - register a tracer with the ftrace system.
1110 * @type - the plugin for the tracer
1112 * Register a new plugin tracer.
1114 int register_tracer(struct tracer
*type
)
1120 pr_info("Tracer must have a name\n");
1124 if (strlen(type
->name
) >= MAX_TRACER_SIZE
) {
1125 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE
);
1129 mutex_lock(&trace_types_lock
);
1131 tracing_selftest_running
= true;
1133 for (t
= trace_types
; t
; t
= t
->next
) {
1134 if (strcmp(type
->name
, t
->name
) == 0) {
1136 pr_info("Tracer %s already registered\n",
1143 if (!type
->set_flag
)
1144 type
->set_flag
= &dummy_set_flag
;
1146 type
->flags
= &dummy_tracer_flags
;
1148 if (!type
->flags
->opts
)
1149 type
->flags
->opts
= dummy_tracer_opt
;
1150 if (!type
->wait_pipe
)
1151 type
->wait_pipe
= default_wait_pipe
;
1153 ret
= run_tracer_selftest(type
);
1157 type
->next
= trace_types
;
1161 tracing_selftest_running
= false;
1162 mutex_unlock(&trace_types_lock
);
1164 if (ret
|| !default_bootup_tracer
)
1167 if (strncmp(default_bootup_tracer
, type
->name
, MAX_TRACER_SIZE
))
1170 printk(KERN_INFO
"Starting tracer '%s'\n", type
->name
);
1171 /* Do we want this tracer to start on bootup? */
1172 tracing_set_tracer(type
->name
);
1173 default_bootup_tracer
= NULL
;
1174 /* disable other selftests, since this will break it. */
1175 tracing_selftest_disabled
= true;
1176 #ifdef CONFIG_FTRACE_STARTUP_TEST
1177 printk(KERN_INFO
"Disabling FTRACE selftests due to running tracer '%s'\n",
1185 void tracing_reset(struct trace_buffer
*buf
, int cpu
)
1187 struct ring_buffer
*buffer
= buf
->buffer
;
1192 ring_buffer_record_disable(buffer
);
1194 /* Make sure all commits have finished */
1195 synchronize_sched();
1196 ring_buffer_reset_cpu(buffer
, cpu
);
1198 ring_buffer_record_enable(buffer
);
1201 void tracing_reset_online_cpus(struct trace_buffer
*buf
)
1203 struct ring_buffer
*buffer
= buf
->buffer
;
1209 ring_buffer_record_disable(buffer
);
1211 /* Make sure all commits have finished */
1212 synchronize_sched();
1214 buf
->time_start
= ftrace_now(buf
->cpu
);
1216 for_each_online_cpu(cpu
)
1217 ring_buffer_reset_cpu(buffer
, cpu
);
1219 ring_buffer_record_enable(buffer
);
1222 void tracing_reset_current(int cpu
)
1224 tracing_reset(&global_trace
.trace_buffer
, cpu
);
1227 void tracing_reset_all_online_cpus(void)
1229 struct trace_array
*tr
;
1231 mutex_lock(&trace_types_lock
);
1232 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
1233 tracing_reset_online_cpus(&tr
->trace_buffer
);
1234 #ifdef CONFIG_TRACER_MAX_TRACE
1235 tracing_reset_online_cpus(&tr
->max_buffer
);
1238 mutex_unlock(&trace_types_lock
);
1241 #define SAVED_CMDLINES 128
1242 #define NO_CMDLINE_MAP UINT_MAX
1243 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
1244 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
1245 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
1246 static int cmdline_idx
;
1247 static arch_spinlock_t trace_cmdline_lock
= __ARCH_SPIN_LOCK_UNLOCKED
;
1249 /* temporary disable recording */
1250 static atomic_t trace_record_cmdline_disabled __read_mostly
;
1252 static void trace_init_cmdlines(void)
1254 memset(&map_pid_to_cmdline
, NO_CMDLINE_MAP
, sizeof(map_pid_to_cmdline
));
1255 memset(&map_cmdline_to_pid
, NO_CMDLINE_MAP
, sizeof(map_cmdline_to_pid
));
1259 int is_tracing_stopped(void)
1261 return global_trace
.stop_count
;
1265 * ftrace_off_permanent - disable all ftrace code permanently
1267 * This should only be called when a serious anomally has
1268 * been detected. This will turn off the function tracing,
1269 * ring buffers, and other tracing utilites. It takes no
1270 * locks and can be called from any context.
1272 void ftrace_off_permanent(void)
1274 tracing_disabled
= 1;
1276 tracing_off_permanent();
1280 * tracing_start - quick start of the tracer
1282 * If tracing is enabled but was stopped by tracing_stop,
1283 * this will start the tracer back up.
1285 void tracing_start(void)
1287 struct ring_buffer
*buffer
;
1288 unsigned long flags
;
1290 if (tracing_disabled
)
1293 raw_spin_lock_irqsave(&global_trace
.start_lock
, flags
);
1294 if (--global_trace
.stop_count
) {
1295 if (global_trace
.stop_count
< 0) {
1296 /* Someone screwed up their debugging */
1298 global_trace
.stop_count
= 0;
1303 /* Prevent the buffers from switching */
1304 arch_spin_lock(&ftrace_max_lock
);
1306 buffer
= global_trace
.trace_buffer
.buffer
;
1308 ring_buffer_record_enable(buffer
);
1310 #ifdef CONFIG_TRACER_MAX_TRACE
1311 buffer
= global_trace
.max_buffer
.buffer
;
1313 ring_buffer_record_enable(buffer
);
1316 arch_spin_unlock(&ftrace_max_lock
);
1320 raw_spin_unlock_irqrestore(&global_trace
.start_lock
, flags
);
1323 static void tracing_start_tr(struct trace_array
*tr
)
1325 struct ring_buffer
*buffer
;
1326 unsigned long flags
;
1328 if (tracing_disabled
)
1331 /* If global, we need to also start the max tracer */
1332 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
1333 return tracing_start();
1335 raw_spin_lock_irqsave(&tr
->start_lock
, flags
);
1337 if (--tr
->stop_count
) {
1338 if (tr
->stop_count
< 0) {
1339 /* Someone screwed up their debugging */
1346 buffer
= tr
->trace_buffer
.buffer
;
1348 ring_buffer_record_enable(buffer
);
1351 raw_spin_unlock_irqrestore(&tr
->start_lock
, flags
);
1355 * tracing_stop - quick stop of the tracer
1357 * Light weight way to stop tracing. Use in conjunction with
1360 void tracing_stop(void)
1362 struct ring_buffer
*buffer
;
1363 unsigned long flags
;
1366 raw_spin_lock_irqsave(&global_trace
.start_lock
, flags
);
1367 if (global_trace
.stop_count
++)
1370 /* Prevent the buffers from switching */
1371 arch_spin_lock(&ftrace_max_lock
);
1373 buffer
= global_trace
.trace_buffer
.buffer
;
1375 ring_buffer_record_disable(buffer
);
1377 #ifdef CONFIG_TRACER_MAX_TRACE
1378 buffer
= global_trace
.max_buffer
.buffer
;
1380 ring_buffer_record_disable(buffer
);
1383 arch_spin_unlock(&ftrace_max_lock
);
1386 raw_spin_unlock_irqrestore(&global_trace
.start_lock
, flags
);
1389 static void tracing_stop_tr(struct trace_array
*tr
)
1391 struct ring_buffer
*buffer
;
1392 unsigned long flags
;
1394 /* If global, we need to also stop the max tracer */
1395 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
1396 return tracing_stop();
1398 raw_spin_lock_irqsave(&tr
->start_lock
, flags
);
1399 if (tr
->stop_count
++)
1402 buffer
= tr
->trace_buffer
.buffer
;
1404 ring_buffer_record_disable(buffer
);
1407 raw_spin_unlock_irqrestore(&tr
->start_lock
, flags
);
1410 void trace_stop_cmdline_recording(void);
1412 static void trace_save_cmdline(struct task_struct
*tsk
)
1416 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
1420 * It's not the end of the world if we don't get
1421 * the lock, but we also don't want to spin
1422 * nor do we want to disable interrupts,
1423 * so if we miss here, then better luck next time.
1425 if (!arch_spin_trylock(&trace_cmdline_lock
))
1428 idx
= map_pid_to_cmdline
[tsk
->pid
];
1429 if (idx
== NO_CMDLINE_MAP
) {
1430 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
1433 * Check whether the cmdline buffer at idx has a pid
1434 * mapped. We are going to overwrite that entry so we
1435 * need to clear the map_pid_to_cmdline. Otherwise we
1436 * would read the new comm for the old pid.
1438 pid
= map_cmdline_to_pid
[idx
];
1439 if (pid
!= NO_CMDLINE_MAP
)
1440 map_pid_to_cmdline
[pid
] = NO_CMDLINE_MAP
;
1442 map_cmdline_to_pid
[idx
] = tsk
->pid
;
1443 map_pid_to_cmdline
[tsk
->pid
] = idx
;
1448 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
1450 arch_spin_unlock(&trace_cmdline_lock
);
1453 void trace_find_cmdline(int pid
, char comm
[])
1458 strcpy(comm
, "<idle>");
1462 if (WARN_ON_ONCE(pid
< 0)) {
1463 strcpy(comm
, "<XXX>");
1467 if (pid
> PID_MAX_DEFAULT
) {
1468 strcpy(comm
, "<...>");
1473 arch_spin_lock(&trace_cmdline_lock
);
1474 map
= map_pid_to_cmdline
[pid
];
1475 if (map
!= NO_CMDLINE_MAP
)
1476 strcpy(comm
, saved_cmdlines
[map
]);
1478 strcpy(comm
, "<...>");
1480 arch_spin_unlock(&trace_cmdline_lock
);
1484 void tracing_record_cmdline(struct task_struct
*tsk
)
1486 if (atomic_read(&trace_record_cmdline_disabled
) || !tracing_is_on())
1489 if (!__this_cpu_read(trace_cmdline_save
))
1492 __this_cpu_write(trace_cmdline_save
, false);
1494 trace_save_cmdline(tsk
);
1498 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
,
1501 struct task_struct
*tsk
= current
;
1503 entry
->preempt_count
= pc
& 0xff;
1504 entry
->pid
= (tsk
) ? tsk
->pid
: 0;
1506 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1507 (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
1509 TRACE_FLAG_IRQS_NOSUPPORT
|
1511 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
1512 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
1513 (need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0);
1515 EXPORT_SYMBOL_GPL(tracing_generic_entry_update
);
1517 struct ring_buffer_event
*
1518 trace_buffer_lock_reserve(struct ring_buffer
*buffer
,
1521 unsigned long flags
, int pc
)
1523 struct ring_buffer_event
*event
;
1525 event
= ring_buffer_lock_reserve(buffer
, len
);
1526 if (event
!= NULL
) {
1527 struct trace_entry
*ent
= ring_buffer_event_data(event
);
1529 tracing_generic_entry_update(ent
, flags
, pc
);
1537 __buffer_unlock_commit(struct ring_buffer
*buffer
, struct ring_buffer_event
*event
)
1539 __this_cpu_write(trace_cmdline_save
, true);
1540 ring_buffer_unlock_commit(buffer
, event
);
1544 __trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1545 struct ring_buffer_event
*event
,
1546 unsigned long flags
, int pc
)
1548 __buffer_unlock_commit(buffer
, event
);
1550 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1551 ftrace_trace_userstack(buffer
, flags
, pc
);
1554 void trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1555 struct ring_buffer_event
*event
,
1556 unsigned long flags
, int pc
)
1558 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
);
1560 EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit
);
1562 struct ring_buffer_event
*
1563 trace_event_buffer_lock_reserve(struct ring_buffer
**current_rb
,
1564 struct ftrace_event_file
*ftrace_file
,
1565 int type
, unsigned long len
,
1566 unsigned long flags
, int pc
)
1568 *current_rb
= ftrace_file
->tr
->trace_buffer
.buffer
;
1569 return trace_buffer_lock_reserve(*current_rb
,
1570 type
, len
, flags
, pc
);
1572 EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve
);
1574 struct ring_buffer_event
*
1575 trace_current_buffer_lock_reserve(struct ring_buffer
**current_rb
,
1576 int type
, unsigned long len
,
1577 unsigned long flags
, int pc
)
1579 *current_rb
= global_trace
.trace_buffer
.buffer
;
1580 return trace_buffer_lock_reserve(*current_rb
,
1581 type
, len
, flags
, pc
);
1583 EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve
);
1585 void trace_current_buffer_unlock_commit(struct ring_buffer
*buffer
,
1586 struct ring_buffer_event
*event
,
1587 unsigned long flags
, int pc
)
1589 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
);
1591 EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit
);
1593 void trace_buffer_unlock_commit_regs(struct ring_buffer
*buffer
,
1594 struct ring_buffer_event
*event
,
1595 unsigned long flags
, int pc
,
1596 struct pt_regs
*regs
)
1598 __buffer_unlock_commit(buffer
, event
);
1600 ftrace_trace_stack_regs(buffer
, flags
, 0, pc
, regs
);
1601 ftrace_trace_userstack(buffer
, flags
, pc
);
1603 EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit_regs
);
1605 void trace_current_buffer_discard_commit(struct ring_buffer
*buffer
,
1606 struct ring_buffer_event
*event
)
1608 ring_buffer_discard_commit(buffer
, event
);
1610 EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit
);
1613 trace_function(struct trace_array
*tr
,
1614 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
1617 struct ftrace_event_call
*call
= &event_function
;
1618 struct ring_buffer
*buffer
= tr
->trace_buffer
.buffer
;
1619 struct ring_buffer_event
*event
;
1620 struct ftrace_entry
*entry
;
1622 /* If we are reading the ring buffer, don't trace */
1623 if (unlikely(__this_cpu_read(ftrace_cpu_disabled
)))
1626 event
= trace_buffer_lock_reserve(buffer
, TRACE_FN
, sizeof(*entry
),
1630 entry
= ring_buffer_event_data(event
);
1632 entry
->parent_ip
= parent_ip
;
1634 if (!filter_check_discard(call
, entry
, buffer
, event
))
1635 __buffer_unlock_commit(buffer
, event
);
1638 #ifdef CONFIG_STACKTRACE
1640 #define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
1641 struct ftrace_stack
{
1642 unsigned long calls
[FTRACE_STACK_MAX_ENTRIES
];
1645 static DEFINE_PER_CPU(struct ftrace_stack
, ftrace_stack
);
1646 static DEFINE_PER_CPU(int, ftrace_stack_reserve
);
1648 static void __ftrace_trace_stack(struct ring_buffer
*buffer
,
1649 unsigned long flags
,
1650 int skip
, int pc
, struct pt_regs
*regs
)
1652 struct ftrace_event_call
*call
= &event_kernel_stack
;
1653 struct ring_buffer_event
*event
;
1654 struct stack_entry
*entry
;
1655 struct stack_trace trace
;
1657 int size
= FTRACE_STACK_ENTRIES
;
1659 trace
.nr_entries
= 0;
1663 * Since events can happen in NMIs there's no safe way to
1664 * use the per cpu ftrace_stacks. We reserve it and if an interrupt
1665 * or NMI comes in, it will just have to use the default
1666 * FTRACE_STACK_SIZE.
1668 preempt_disable_notrace();
1670 use_stack
= __this_cpu_inc_return(ftrace_stack_reserve
);
1672 * We don't need any atomic variables, just a barrier.
1673 * If an interrupt comes in, we don't care, because it would
1674 * have exited and put the counter back to what we want.
1675 * We just need a barrier to keep gcc from moving things
1679 if (use_stack
== 1) {
1680 trace
.entries
= &__get_cpu_var(ftrace_stack
).calls
[0];
1681 trace
.max_entries
= FTRACE_STACK_MAX_ENTRIES
;
1684 save_stack_trace_regs(regs
, &trace
);
1686 save_stack_trace(&trace
);
1688 if (trace
.nr_entries
> size
)
1689 size
= trace
.nr_entries
;
1691 /* From now on, use_stack is a boolean */
1694 size
*= sizeof(unsigned long);
1696 event
= trace_buffer_lock_reserve(buffer
, TRACE_STACK
,
1697 sizeof(*entry
) + size
, flags
, pc
);
1700 entry
= ring_buffer_event_data(event
);
1702 memset(&entry
->caller
, 0, size
);
1705 memcpy(&entry
->caller
, trace
.entries
,
1706 trace
.nr_entries
* sizeof(unsigned long));
1708 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1709 trace
.entries
= entry
->caller
;
1711 save_stack_trace_regs(regs
, &trace
);
1713 save_stack_trace(&trace
);
1716 entry
->size
= trace
.nr_entries
;
1718 if (!filter_check_discard(call
, entry
, buffer
, event
))
1719 __buffer_unlock_commit(buffer
, event
);
1722 /* Again, don't let gcc optimize things here */
1724 __this_cpu_dec(ftrace_stack_reserve
);
1725 preempt_enable_notrace();
1729 void ftrace_trace_stack_regs(struct ring_buffer
*buffer
, unsigned long flags
,
1730 int skip
, int pc
, struct pt_regs
*regs
)
1732 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1735 __ftrace_trace_stack(buffer
, flags
, skip
, pc
, regs
);
1738 void ftrace_trace_stack(struct ring_buffer
*buffer
, unsigned long flags
,
1741 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1744 __ftrace_trace_stack(buffer
, flags
, skip
, pc
, NULL
);
1747 void __trace_stack(struct trace_array
*tr
, unsigned long flags
, int skip
,
1750 __ftrace_trace_stack(tr
->trace_buffer
.buffer
, flags
, skip
, pc
, NULL
);
1754 * trace_dump_stack - record a stack back trace in the trace buffer
1755 * @skip: Number of functions to skip (helper handlers)
1757 void trace_dump_stack(int skip
)
1759 unsigned long flags
;
1761 if (tracing_disabled
|| tracing_selftest_running
)
1764 local_save_flags(flags
);
1767 * Skip 3 more, seems to get us at the caller of
1771 __ftrace_trace_stack(global_trace
.trace_buffer
.buffer
,
1772 flags
, skip
, preempt_count(), NULL
);
1775 static DEFINE_PER_CPU(int, user_stack_count
);
1778 ftrace_trace_userstack(struct ring_buffer
*buffer
, unsigned long flags
, int pc
)
1780 struct ftrace_event_call
*call
= &event_user_stack
;
1781 struct ring_buffer_event
*event
;
1782 struct userstack_entry
*entry
;
1783 struct stack_trace trace
;
1785 if (!(trace_flags
& TRACE_ITER_USERSTACKTRACE
))
1789 * NMIs can not handle page faults, even with fix ups.
1790 * The save user stack can (and often does) fault.
1792 if (unlikely(in_nmi()))
1796 * prevent recursion, since the user stack tracing may
1797 * trigger other kernel events.
1800 if (__this_cpu_read(user_stack_count
))
1803 __this_cpu_inc(user_stack_count
);
1805 event
= trace_buffer_lock_reserve(buffer
, TRACE_USER_STACK
,
1806 sizeof(*entry
), flags
, pc
);
1808 goto out_drop_count
;
1809 entry
= ring_buffer_event_data(event
);
1811 entry
->tgid
= current
->tgid
;
1812 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
1814 trace
.nr_entries
= 0;
1815 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1817 trace
.entries
= entry
->caller
;
1819 save_stack_trace_user(&trace
);
1820 if (!filter_check_discard(call
, entry
, buffer
, event
))
1821 __buffer_unlock_commit(buffer
, event
);
1824 __this_cpu_dec(user_stack_count
);
1830 static void __trace_userstack(struct trace_array
*tr
, unsigned long flags
)
1832 ftrace_trace_userstack(tr
, flags
, preempt_count());
1836 #endif /* CONFIG_STACKTRACE */
1838 /* created for use with alloc_percpu */
1839 struct trace_buffer_struct
{
1840 char buffer
[TRACE_BUF_SIZE
];
1843 static struct trace_buffer_struct
*trace_percpu_buffer
;
1844 static struct trace_buffer_struct
*trace_percpu_sirq_buffer
;
1845 static struct trace_buffer_struct
*trace_percpu_irq_buffer
;
1846 static struct trace_buffer_struct
*trace_percpu_nmi_buffer
;
1849 * The buffer used is dependent on the context. There is a per cpu
1850 * buffer for normal context, softirq contex, hard irq context and
1851 * for NMI context. Thise allows for lockless recording.
1853 * Note, if the buffers failed to be allocated, then this returns NULL
1855 static char *get_trace_buf(void)
1857 struct trace_buffer_struct
*percpu_buffer
;
1860 * If we have allocated per cpu buffers, then we do not
1861 * need to do any locking.
1864 percpu_buffer
= trace_percpu_nmi_buffer
;
1866 percpu_buffer
= trace_percpu_irq_buffer
;
1867 else if (in_softirq())
1868 percpu_buffer
= trace_percpu_sirq_buffer
;
1870 percpu_buffer
= trace_percpu_buffer
;
1875 return this_cpu_ptr(&percpu_buffer
->buffer
[0]);
1878 static int alloc_percpu_trace_buffer(void)
1880 struct trace_buffer_struct
*buffers
;
1881 struct trace_buffer_struct
*sirq_buffers
;
1882 struct trace_buffer_struct
*irq_buffers
;
1883 struct trace_buffer_struct
*nmi_buffers
;
1885 buffers
= alloc_percpu(struct trace_buffer_struct
);
1889 sirq_buffers
= alloc_percpu(struct trace_buffer_struct
);
1893 irq_buffers
= alloc_percpu(struct trace_buffer_struct
);
1897 nmi_buffers
= alloc_percpu(struct trace_buffer_struct
);
1901 trace_percpu_buffer
= buffers
;
1902 trace_percpu_sirq_buffer
= sirq_buffers
;
1903 trace_percpu_irq_buffer
= irq_buffers
;
1904 trace_percpu_nmi_buffer
= nmi_buffers
;
1909 free_percpu(irq_buffers
);
1911 free_percpu(sirq_buffers
);
1913 free_percpu(buffers
);
1915 WARN(1, "Could not allocate percpu trace_printk buffer");
1919 static int buffers_allocated
;
1921 void trace_printk_init_buffers(void)
1923 if (buffers_allocated
)
1926 if (alloc_percpu_trace_buffer())
1929 pr_info("ftrace: Allocated trace_printk buffers\n");
1931 /* Expand the buffers to set size */
1932 tracing_update_buffers();
1934 buffers_allocated
= 1;
1937 * trace_printk_init_buffers() can be called by modules.
1938 * If that happens, then we need to start cmdline recording
1939 * directly here. If the global_trace.buffer is already
1940 * allocated here, then this was called by module code.
1942 if (global_trace
.trace_buffer
.buffer
)
1943 tracing_start_cmdline_record();
1946 void trace_printk_start_comm(void)
1948 /* Start tracing comms if trace printk is set */
1949 if (!buffers_allocated
)
1951 tracing_start_cmdline_record();
1954 static void trace_printk_start_stop_comm(int enabled
)
1956 if (!buffers_allocated
)
1960 tracing_start_cmdline_record();
1962 tracing_stop_cmdline_record();
1966 * trace_vbprintk - write binary msg to tracing buffer
1969 int trace_vbprintk(unsigned long ip
, const char *fmt
, va_list args
)
1971 struct ftrace_event_call
*call
= &event_bprint
;
1972 struct ring_buffer_event
*event
;
1973 struct ring_buffer
*buffer
;
1974 struct trace_array
*tr
= &global_trace
;
1975 struct bprint_entry
*entry
;
1976 unsigned long flags
;
1978 int len
= 0, size
, pc
;
1980 if (unlikely(tracing_selftest_running
|| tracing_disabled
))
1983 /* Don't pollute graph traces with trace_vprintk internals */
1984 pause_graph_tracing();
1986 pc
= preempt_count();
1987 preempt_disable_notrace();
1989 tbuffer
= get_trace_buf();
1995 len
= vbin_printf((u32
*)tbuffer
, TRACE_BUF_SIZE
/sizeof(int), fmt
, args
);
1997 if (len
> TRACE_BUF_SIZE
/sizeof(int) || len
< 0)
2000 local_save_flags(flags
);
2001 size
= sizeof(*entry
) + sizeof(u32
) * len
;
2002 buffer
= tr
->trace_buffer
.buffer
;
2003 event
= trace_buffer_lock_reserve(buffer
, TRACE_BPRINT
, size
,
2007 entry
= ring_buffer_event_data(event
);
2011 memcpy(entry
->buf
, tbuffer
, sizeof(u32
) * len
);
2012 if (!filter_check_discard(call
, entry
, buffer
, event
)) {
2013 __buffer_unlock_commit(buffer
, event
);
2014 ftrace_trace_stack(buffer
, flags
, 6, pc
);
2018 preempt_enable_notrace();
2019 unpause_graph_tracing();
2023 EXPORT_SYMBOL_GPL(trace_vbprintk
);
2026 __trace_array_vprintk(struct ring_buffer
*buffer
,
2027 unsigned long ip
, const char *fmt
, va_list args
)
2029 struct ftrace_event_call
*call
= &event_print
;
2030 struct ring_buffer_event
*event
;
2031 int len
= 0, size
, pc
;
2032 struct print_entry
*entry
;
2033 unsigned long flags
;
2036 if (tracing_disabled
|| tracing_selftest_running
)
2039 /* Don't pollute graph traces with trace_vprintk internals */
2040 pause_graph_tracing();
2042 pc
= preempt_count();
2043 preempt_disable_notrace();
2046 tbuffer
= get_trace_buf();
2052 len
= vsnprintf(tbuffer
, TRACE_BUF_SIZE
, fmt
, args
);
2053 if (len
> TRACE_BUF_SIZE
)
2056 local_save_flags(flags
);
2057 size
= sizeof(*entry
) + len
+ 1;
2058 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, size
,
2062 entry
= ring_buffer_event_data(event
);
2065 memcpy(&entry
->buf
, tbuffer
, len
);
2066 entry
->buf
[len
] = '\0';
2067 if (!filter_check_discard(call
, entry
, buffer
, event
)) {
2068 __buffer_unlock_commit(buffer
, event
);
2069 ftrace_trace_stack(buffer
, flags
, 6, pc
);
2072 preempt_enable_notrace();
2073 unpause_graph_tracing();
2078 int trace_array_vprintk(struct trace_array
*tr
,
2079 unsigned long ip
, const char *fmt
, va_list args
)
2081 return __trace_array_vprintk(tr
->trace_buffer
.buffer
, ip
, fmt
, args
);
2084 int trace_array_printk(struct trace_array
*tr
,
2085 unsigned long ip
, const char *fmt
, ...)
2090 if (!(trace_flags
& TRACE_ITER_PRINTK
))
2094 ret
= trace_array_vprintk(tr
, ip
, fmt
, ap
);
2099 int trace_array_printk_buf(struct ring_buffer
*buffer
,
2100 unsigned long ip
, const char *fmt
, ...)
2105 if (!(trace_flags
& TRACE_ITER_PRINTK
))
2109 ret
= __trace_array_vprintk(buffer
, ip
, fmt
, ap
);
2114 int trace_vprintk(unsigned long ip
, const char *fmt
, va_list args
)
2116 return trace_array_vprintk(&global_trace
, ip
, fmt
, args
);
2118 EXPORT_SYMBOL_GPL(trace_vprintk
);
2120 static void trace_iterator_increment(struct trace_iterator
*iter
)
2122 struct ring_buffer_iter
*buf_iter
= trace_buffer_iter(iter
, iter
->cpu
);
2126 ring_buffer_read(buf_iter
, NULL
);
2129 static struct trace_entry
*
2130 peek_next_entry(struct trace_iterator
*iter
, int cpu
, u64
*ts
,
2131 unsigned long *lost_events
)
2133 struct ring_buffer_event
*event
;
2134 struct ring_buffer_iter
*buf_iter
= trace_buffer_iter(iter
, cpu
);
2137 event
= ring_buffer_iter_peek(buf_iter
, ts
);
2139 event
= ring_buffer_peek(iter
->trace_buffer
->buffer
, cpu
, ts
,
2143 iter
->ent_size
= ring_buffer_event_length(event
);
2144 return ring_buffer_event_data(event
);
2150 static struct trace_entry
*
2151 __find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
,
2152 unsigned long *missing_events
, u64
*ent_ts
)
2154 struct ring_buffer
*buffer
= iter
->trace_buffer
->buffer
;
2155 struct trace_entry
*ent
, *next
= NULL
;
2156 unsigned long lost_events
= 0, next_lost
= 0;
2157 int cpu_file
= iter
->cpu_file
;
2158 u64 next_ts
= 0, ts
;
2164 * If we are in a per_cpu trace file, don't bother by iterating over
2165 * all cpu and peek directly.
2167 if (cpu_file
> RING_BUFFER_ALL_CPUS
) {
2168 if (ring_buffer_empty_cpu(buffer
, cpu_file
))
2170 ent
= peek_next_entry(iter
, cpu_file
, ent_ts
, missing_events
);
2172 *ent_cpu
= cpu_file
;
2177 for_each_tracing_cpu(cpu
) {
2179 if (ring_buffer_empty_cpu(buffer
, cpu
))
2182 ent
= peek_next_entry(iter
, cpu
, &ts
, &lost_events
);
2185 * Pick the entry with the smallest timestamp:
2187 if (ent
&& (!next
|| ts
< next_ts
)) {
2191 next_lost
= lost_events
;
2192 next_size
= iter
->ent_size
;
2196 iter
->ent_size
= next_size
;
2199 *ent_cpu
= next_cpu
;
2205 *missing_events
= next_lost
;
2210 /* Find the next real entry, without updating the iterator itself */
2211 struct trace_entry
*trace_find_next_entry(struct trace_iterator
*iter
,
2212 int *ent_cpu
, u64
*ent_ts
)
2214 return __find_next_entry(iter
, ent_cpu
, NULL
, ent_ts
);
2217 /* Find the next real entry, and increment the iterator to the next entry */
2218 void *trace_find_next_entry_inc(struct trace_iterator
*iter
)
2220 iter
->ent
= __find_next_entry(iter
, &iter
->cpu
,
2221 &iter
->lost_events
, &iter
->ts
);
2224 trace_iterator_increment(iter
);
2226 return iter
->ent
? iter
: NULL
;
2229 static void trace_consume(struct trace_iterator
*iter
)
2231 ring_buffer_consume(iter
->trace_buffer
->buffer
, iter
->cpu
, &iter
->ts
,
2232 &iter
->lost_events
);
2235 static void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
2237 struct trace_iterator
*iter
= m
->private;
2241 WARN_ON_ONCE(iter
->leftover
);
2245 /* can't go backwards */
2250 ent
= trace_find_next_entry_inc(iter
);
2254 while (ent
&& iter
->idx
< i
)
2255 ent
= trace_find_next_entry_inc(iter
);
2262 void tracing_iter_reset(struct trace_iterator
*iter
, int cpu
)
2264 struct ring_buffer_event
*event
;
2265 struct ring_buffer_iter
*buf_iter
;
2266 unsigned long entries
= 0;
2269 per_cpu_ptr(iter
->trace_buffer
->data
, cpu
)->skipped_entries
= 0;
2271 buf_iter
= trace_buffer_iter(iter
, cpu
);
2275 ring_buffer_iter_reset(buf_iter
);
2278 * We could have the case with the max latency tracers
2279 * that a reset never took place on a cpu. This is evident
2280 * by the timestamp being before the start of the buffer.
2282 while ((event
= ring_buffer_iter_peek(buf_iter
, &ts
))) {
2283 if (ts
>= iter
->trace_buffer
->time_start
)
2286 ring_buffer_read(buf_iter
, NULL
);
2289 per_cpu_ptr(iter
->trace_buffer
->data
, cpu
)->skipped_entries
= entries
;
2293 * The current tracer is copied to avoid a global locking
2296 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
2298 struct trace_iterator
*iter
= m
->private;
2299 struct trace_array
*tr
= iter
->tr
;
2300 int cpu_file
= iter
->cpu_file
;
2306 * copy the tracer to avoid using a global lock all around.
2307 * iter->trace is a copy of current_trace, the pointer to the
2308 * name may be used instead of a strcmp(), as iter->trace->name
2309 * will point to the same string as current_trace->name.
2311 mutex_lock(&trace_types_lock
);
2312 if (unlikely(tr
->current_trace
&& iter
->trace
->name
!= tr
->current_trace
->name
))
2313 *iter
->trace
= *tr
->current_trace
;
2314 mutex_unlock(&trace_types_lock
);
2316 #ifdef CONFIG_TRACER_MAX_TRACE
2317 if (iter
->snapshot
&& iter
->trace
->use_max_tr
)
2318 return ERR_PTR(-EBUSY
);
2321 if (!iter
->snapshot
)
2322 atomic_inc(&trace_record_cmdline_disabled
);
2324 if (*pos
!= iter
->pos
) {
2329 if (cpu_file
== RING_BUFFER_ALL_CPUS
) {
2330 for_each_tracing_cpu(cpu
)
2331 tracing_iter_reset(iter
, cpu
);
2333 tracing_iter_reset(iter
, cpu_file
);
2336 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
2341 * If we overflowed the seq_file before, then we want
2342 * to just reuse the trace_seq buffer again.
2348 p
= s_next(m
, p
, &l
);
2352 trace_event_read_lock();
2353 trace_access_lock(cpu_file
);
2357 static void s_stop(struct seq_file
*m
, void *p
)
2359 struct trace_iterator
*iter
= m
->private;
2361 #ifdef CONFIG_TRACER_MAX_TRACE
2362 if (iter
->snapshot
&& iter
->trace
->use_max_tr
)
2366 if (!iter
->snapshot
)
2367 atomic_dec(&trace_record_cmdline_disabled
);
2369 trace_access_unlock(iter
->cpu_file
);
2370 trace_event_read_unlock();
2374 get_total_entries(struct trace_buffer
*buf
,
2375 unsigned long *total
, unsigned long *entries
)
2377 unsigned long count
;
2383 for_each_tracing_cpu(cpu
) {
2384 count
= ring_buffer_entries_cpu(buf
->buffer
, cpu
);
2386 * If this buffer has skipped entries, then we hold all
2387 * entries for the trace and we need to ignore the
2388 * ones before the time stamp.
2390 if (per_cpu_ptr(buf
->data
, cpu
)->skipped_entries
) {
2391 count
-= per_cpu_ptr(buf
->data
, cpu
)->skipped_entries
;
2392 /* total is the same as the entries */
2396 ring_buffer_overrun_cpu(buf
->buffer
, cpu
);
2401 static void print_lat_help_header(struct seq_file
*m
)
2403 seq_puts(m
, "# _------=> CPU# \n");
2404 seq_puts(m
, "# / _-----=> irqs-off \n");
2405 seq_puts(m
, "# | / _----=> need-resched \n");
2406 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
2407 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
2408 seq_puts(m
, "# |||| / delay \n");
2409 seq_puts(m
, "# cmd pid ||||| time | caller \n");
2410 seq_puts(m
, "# \\ / ||||| \\ | / \n");
2413 static void print_event_info(struct trace_buffer
*buf
, struct seq_file
*m
)
2415 unsigned long total
;
2416 unsigned long entries
;
2418 get_total_entries(buf
, &total
, &entries
);
2419 seq_printf(m
, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
2420 entries
, total
, num_online_cpus());
2424 static void print_func_help_header(struct trace_buffer
*buf
, struct seq_file
*m
)
2426 print_event_info(buf
, m
);
2427 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
2428 seq_puts(m
, "# | | | | |\n");
2431 static void print_func_help_header_irq(struct trace_buffer
*buf
, struct seq_file
*m
)
2433 print_event_info(buf
, m
);
2434 seq_puts(m
, "# _-----=> irqs-off\n");
2435 seq_puts(m
, "# / _----=> need-resched\n");
2436 seq_puts(m
, "# | / _---=> hardirq/softirq\n");
2437 seq_puts(m
, "# || / _--=> preempt-depth\n");
2438 seq_puts(m
, "# ||| / delay\n");
2439 seq_puts(m
, "# TASK-PID CPU# |||| TIMESTAMP FUNCTION\n");
2440 seq_puts(m
, "# | | | |||| | |\n");
2444 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
2446 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
2447 struct trace_buffer
*buf
= iter
->trace_buffer
;
2448 struct trace_array_cpu
*data
= per_cpu_ptr(buf
->data
, buf
->cpu
);
2449 struct tracer
*type
= iter
->trace
;
2450 unsigned long entries
;
2451 unsigned long total
;
2452 const char *name
= "preemption";
2456 get_total_entries(buf
, &total
, &entries
);
2458 seq_printf(m
, "# %s latency trace v1.1.5 on %s\n",
2460 seq_puts(m
, "# -----------------------------------"
2461 "---------------------------------\n");
2462 seq_printf(m
, "# latency: %lu us, #%lu/%lu, CPU#%d |"
2463 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
2464 nsecs_to_usecs(data
->saved_latency
),
2468 #if defined(CONFIG_PREEMPT_NONE)
2470 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
2472 #elif defined(CONFIG_PREEMPT)
2477 /* These are reserved for later use */
2480 seq_printf(m
, " #P:%d)\n", num_online_cpus());
2484 seq_puts(m
, "# -----------------\n");
2485 seq_printf(m
, "# | task: %.16s-%d "
2486 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
2487 data
->comm
, data
->pid
,
2488 from_kuid_munged(seq_user_ns(m
), data
->uid
), data
->nice
,
2489 data
->policy
, data
->rt_priority
);
2490 seq_puts(m
, "# -----------------\n");
2492 if (data
->critical_start
) {
2493 seq_puts(m
, "# => started at: ");
2494 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
2495 trace_print_seq(m
, &iter
->seq
);
2496 seq_puts(m
, "\n# => ended at: ");
2497 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
2498 trace_print_seq(m
, &iter
->seq
);
2499 seq_puts(m
, "\n#\n");
2505 static void test_cpu_buff_start(struct trace_iterator
*iter
)
2507 struct trace_seq
*s
= &iter
->seq
;
2509 if (!(trace_flags
& TRACE_ITER_ANNOTATE
))
2512 if (!(iter
->iter_flags
& TRACE_FILE_ANNOTATE
))
2515 if (cpumask_test_cpu(iter
->cpu
, iter
->started
))
2518 if (per_cpu_ptr(iter
->trace_buffer
->data
, iter
->cpu
)->skipped_entries
)
2521 cpumask_set_cpu(iter
->cpu
, iter
->started
);
2523 /* Don't print started cpu buffer for the first entry of the trace */
2525 trace_seq_printf(s
, "##### CPU %u buffer started ####\n",
2529 static enum print_line_t
print_trace_fmt(struct trace_iterator
*iter
)
2531 struct trace_seq
*s
= &iter
->seq
;
2532 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
2533 struct trace_entry
*entry
;
2534 struct trace_event
*event
;
2538 test_cpu_buff_start(iter
);
2540 event
= ftrace_find_event(entry
->type
);
2542 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2543 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
2544 if (!trace_print_lat_context(iter
))
2547 if (!trace_print_context(iter
))
2553 return event
->funcs
->trace(iter
, sym_flags
, event
);
2555 if (!trace_seq_printf(s
, "Unknown type %d\n", entry
->type
))
2558 return TRACE_TYPE_HANDLED
;
2560 return TRACE_TYPE_PARTIAL_LINE
;
2563 static enum print_line_t
print_raw_fmt(struct trace_iterator
*iter
)
2565 struct trace_seq
*s
= &iter
->seq
;
2566 struct trace_entry
*entry
;
2567 struct trace_event
*event
;
2571 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2572 if (!trace_seq_printf(s
, "%d %d %llu ",
2573 entry
->pid
, iter
->cpu
, iter
->ts
))
2577 event
= ftrace_find_event(entry
->type
);
2579 return event
->funcs
->raw(iter
, 0, event
);
2581 if (!trace_seq_printf(s
, "%d ?\n", entry
->type
))
2584 return TRACE_TYPE_HANDLED
;
2586 return TRACE_TYPE_PARTIAL_LINE
;
2589 static enum print_line_t
print_hex_fmt(struct trace_iterator
*iter
)
2591 struct trace_seq
*s
= &iter
->seq
;
2592 unsigned char newline
= '\n';
2593 struct trace_entry
*entry
;
2594 struct trace_event
*event
;
2598 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2599 SEQ_PUT_HEX_FIELD_RET(s
, entry
->pid
);
2600 SEQ_PUT_HEX_FIELD_RET(s
, iter
->cpu
);
2601 SEQ_PUT_HEX_FIELD_RET(s
, iter
->ts
);
2604 event
= ftrace_find_event(entry
->type
);
2606 enum print_line_t ret
= event
->funcs
->hex(iter
, 0, event
);
2607 if (ret
!= TRACE_TYPE_HANDLED
)
2611 SEQ_PUT_FIELD_RET(s
, newline
);
2613 return TRACE_TYPE_HANDLED
;
2616 static enum print_line_t
print_bin_fmt(struct trace_iterator
*iter
)
2618 struct trace_seq
*s
= &iter
->seq
;
2619 struct trace_entry
*entry
;
2620 struct trace_event
*event
;
2624 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2625 SEQ_PUT_FIELD_RET(s
, entry
->pid
);
2626 SEQ_PUT_FIELD_RET(s
, iter
->cpu
);
2627 SEQ_PUT_FIELD_RET(s
, iter
->ts
);
2630 event
= ftrace_find_event(entry
->type
);
2631 return event
? event
->funcs
->binary(iter
, 0, event
) :
2635 int trace_empty(struct trace_iterator
*iter
)
2637 struct ring_buffer_iter
*buf_iter
;
2640 /* If we are looking at one CPU buffer, only check that one */
2641 if (iter
->cpu_file
!= RING_BUFFER_ALL_CPUS
) {
2642 cpu
= iter
->cpu_file
;
2643 buf_iter
= trace_buffer_iter(iter
, cpu
);
2645 if (!ring_buffer_iter_empty(buf_iter
))
2648 if (!ring_buffer_empty_cpu(iter
->trace_buffer
->buffer
, cpu
))
2654 for_each_tracing_cpu(cpu
) {
2655 buf_iter
= trace_buffer_iter(iter
, cpu
);
2657 if (!ring_buffer_iter_empty(buf_iter
))
2660 if (!ring_buffer_empty_cpu(iter
->trace_buffer
->buffer
, cpu
))
2668 /* Called with trace_event_read_lock() held. */
2669 enum print_line_t
print_trace_line(struct trace_iterator
*iter
)
2671 enum print_line_t ret
;
2673 if (iter
->lost_events
&&
2674 !trace_seq_printf(&iter
->seq
, "CPU:%d [LOST %lu EVENTS]\n",
2675 iter
->cpu
, iter
->lost_events
))
2676 return TRACE_TYPE_PARTIAL_LINE
;
2678 if (iter
->trace
&& iter
->trace
->print_line
) {
2679 ret
= iter
->trace
->print_line(iter
);
2680 if (ret
!= TRACE_TYPE_UNHANDLED
)
2684 if (iter
->ent
->type
== TRACE_BPUTS
&&
2685 trace_flags
& TRACE_ITER_PRINTK
&&
2686 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2687 return trace_print_bputs_msg_only(iter
);
2689 if (iter
->ent
->type
== TRACE_BPRINT
&&
2690 trace_flags
& TRACE_ITER_PRINTK
&&
2691 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2692 return trace_print_bprintk_msg_only(iter
);
2694 if (iter
->ent
->type
== TRACE_PRINT
&&
2695 trace_flags
& TRACE_ITER_PRINTK
&&
2696 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2697 return trace_print_printk_msg_only(iter
);
2699 if (trace_flags
& TRACE_ITER_BIN
)
2700 return print_bin_fmt(iter
);
2702 if (trace_flags
& TRACE_ITER_HEX
)
2703 return print_hex_fmt(iter
);
2705 if (trace_flags
& TRACE_ITER_RAW
)
2706 return print_raw_fmt(iter
);
2708 return print_trace_fmt(iter
);
2711 void trace_latency_header(struct seq_file
*m
)
2713 struct trace_iterator
*iter
= m
->private;
2715 /* print nothing if the buffers are empty */
2716 if (trace_empty(iter
))
2719 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
)
2720 print_trace_header(m
, iter
);
2722 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2723 print_lat_help_header(m
);
2726 void trace_default_header(struct seq_file
*m
)
2728 struct trace_iterator
*iter
= m
->private;
2730 if (!(trace_flags
& TRACE_ITER_CONTEXT_INFO
))
2733 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
2734 /* print nothing if the buffers are empty */
2735 if (trace_empty(iter
))
2737 print_trace_header(m
, iter
);
2738 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2739 print_lat_help_header(m
);
2741 if (!(trace_flags
& TRACE_ITER_VERBOSE
)) {
2742 if (trace_flags
& TRACE_ITER_IRQ_INFO
)
2743 print_func_help_header_irq(iter
->trace_buffer
, m
);
2745 print_func_help_header(iter
->trace_buffer
, m
);
2750 static void test_ftrace_alive(struct seq_file
*m
)
2752 if (!ftrace_is_dead())
2754 seq_printf(m
, "# WARNING: FUNCTION TRACING IS CORRUPTED\n");
2755 seq_printf(m
, "# MAY BE MISSING FUNCTION EVENTS\n");
2758 #ifdef CONFIG_TRACER_MAX_TRACE
2759 static void show_snapshot_main_help(struct seq_file
*m
)
2761 seq_printf(m
, "# echo 0 > snapshot : Clears and frees snapshot buffer\n");
2762 seq_printf(m
, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
2763 seq_printf(m
, "# Takes a snapshot of the main buffer.\n");
2764 seq_printf(m
, "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate)\n");
2765 seq_printf(m
, "# (Doesn't have to be '2' works with any number that\n");
2766 seq_printf(m
, "# is not a '0' or '1')\n");
2769 static void show_snapshot_percpu_help(struct seq_file
*m
)
2771 seq_printf(m
, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
2772 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
2773 seq_printf(m
, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
2774 seq_printf(m
, "# Takes a snapshot of the main buffer for this cpu.\n");
2776 seq_printf(m
, "# echo 1 > snapshot : Not supported with this kernel.\n");
2777 seq_printf(m
, "# Must use main snapshot file to allocate.\n");
2779 seq_printf(m
, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n");
2780 seq_printf(m
, "# (Doesn't have to be '2' works with any number that\n");
2781 seq_printf(m
, "# is not a '0' or '1')\n");
2784 static void print_snapshot_help(struct seq_file
*m
, struct trace_iterator
*iter
)
2786 if (iter
->tr
->allocated_snapshot
)
2787 seq_printf(m
, "#\n# * Snapshot is allocated *\n#\n");
2789 seq_printf(m
, "#\n# * Snapshot is freed *\n#\n");
2791 seq_printf(m
, "# Snapshot commands:\n");
2792 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
)
2793 show_snapshot_main_help(m
);
2795 show_snapshot_percpu_help(m
);
2798 /* Should never be called */
2799 static inline void print_snapshot_help(struct seq_file
*m
, struct trace_iterator
*iter
) { }
2802 static int s_show(struct seq_file
*m
, void *v
)
2804 struct trace_iterator
*iter
= v
;
2807 if (iter
->ent
== NULL
) {
2809 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
2811 test_ftrace_alive(m
);
2813 if (iter
->snapshot
&& trace_empty(iter
))
2814 print_snapshot_help(m
, iter
);
2815 else if (iter
->trace
&& iter
->trace
->print_header
)
2816 iter
->trace
->print_header(m
);
2818 trace_default_header(m
);
2820 } else if (iter
->leftover
) {
2822 * If we filled the seq_file buffer earlier, we
2823 * want to just show it now.
2825 ret
= trace_print_seq(m
, &iter
->seq
);
2827 /* ret should this time be zero, but you never know */
2828 iter
->leftover
= ret
;
2831 print_trace_line(iter
);
2832 ret
= trace_print_seq(m
, &iter
->seq
);
2834 * If we overflow the seq_file buffer, then it will
2835 * ask us for this data again at start up.
2837 * ret is 0 if seq_file write succeeded.
2840 iter
->leftover
= ret
;
2846 static const struct seq_operations tracer_seq_ops
= {
2853 static struct trace_iterator
*
2854 __tracing_open(struct trace_array
*tr
, struct trace_cpu
*tc
,
2855 struct inode
*inode
, struct file
*file
, bool snapshot
)
2857 struct trace_iterator
*iter
;
2860 if (tracing_disabled
)
2861 return ERR_PTR(-ENODEV
);
2863 iter
= __seq_open_private(file
, &tracer_seq_ops
, sizeof(*iter
));
2865 return ERR_PTR(-ENOMEM
);
2867 iter
->buffer_iter
= kzalloc(sizeof(*iter
->buffer_iter
) * num_possible_cpus(),
2869 if (!iter
->buffer_iter
)
2873 * We make a copy of the current tracer to avoid concurrent
2874 * changes on it while we are reading.
2876 mutex_lock(&trace_types_lock
);
2877 iter
->trace
= kzalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
2881 *iter
->trace
= *tr
->current_trace
;
2883 if (!zalloc_cpumask_var(&iter
->started
, GFP_KERNEL
))
2888 #ifdef CONFIG_TRACER_MAX_TRACE
2889 /* Currently only the top directory has a snapshot */
2890 if (tr
->current_trace
->print_max
|| snapshot
)
2891 iter
->trace_buffer
= &tr
->max_buffer
;
2894 iter
->trace_buffer
= &tr
->trace_buffer
;
2895 iter
->snapshot
= snapshot
;
2897 mutex_init(&iter
->mutex
);
2898 iter
->cpu_file
= tc
->cpu
;
2900 /* Notify the tracer early; before we stop tracing. */
2901 if (iter
->trace
&& iter
->trace
->open
)
2902 iter
->trace
->open(iter
);
2904 /* Annotate start of buffers if we had overruns */
2905 if (ring_buffer_overruns(iter
->trace_buffer
->buffer
))
2906 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
2908 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
2909 if (trace_clocks
[tr
->clock_id
].in_ns
)
2910 iter
->iter_flags
|= TRACE_FILE_TIME_IN_NS
;
2912 /* stop the trace while dumping if we are not opening "snapshot" */
2913 if (!iter
->snapshot
)
2914 tracing_stop_tr(tr
);
2916 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
) {
2917 for_each_tracing_cpu(cpu
) {
2918 iter
->buffer_iter
[cpu
] =
2919 ring_buffer_read_prepare(iter
->trace_buffer
->buffer
, cpu
);
2921 ring_buffer_read_prepare_sync();
2922 for_each_tracing_cpu(cpu
) {
2923 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2924 tracing_iter_reset(iter
, cpu
);
2927 cpu
= iter
->cpu_file
;
2928 iter
->buffer_iter
[cpu
] =
2929 ring_buffer_read_prepare(iter
->trace_buffer
->buffer
, cpu
);
2930 ring_buffer_read_prepare_sync();
2931 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2932 tracing_iter_reset(iter
, cpu
);
2935 mutex_unlock(&trace_types_lock
);
2940 mutex_unlock(&trace_types_lock
);
2942 kfree(iter
->buffer_iter
);
2944 seq_release_private(inode
, file
);
2945 return ERR_PTR(-ENOMEM
);
2948 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
2950 if (tracing_disabled
)
2953 filp
->private_data
= inode
->i_private
;
2958 * Open and update trace_array ref count.
2959 * Must have the current trace_array passed to it.
2961 static int tracing_open_generic_tr(struct inode
*inode
, struct file
*filp
)
2963 struct trace_array
*tr
= inode
->i_private
;
2965 if (tracing_disabled
)
2968 if (trace_array_get(tr
) < 0)
2971 filp
->private_data
= inode
->i_private
;
2977 static int tracing_open_generic_tc(struct inode
*inode
, struct file
*filp
)
2979 struct trace_cpu
*tc
= inode
->i_private
;
2980 struct trace_array
*tr
= tc
->tr
;
2982 if (tracing_disabled
)
2985 if (trace_array_get(tr
) < 0)
2988 filp
->private_data
= inode
->i_private
;
2994 static int tracing_release(struct inode
*inode
, struct file
*file
)
2996 struct seq_file
*m
= file
->private_data
;
2997 struct trace_iterator
*iter
;
2998 struct trace_array
*tr
;
3001 /* Writes do not use seq_file, need to grab tr from inode */
3002 if (!(file
->f_mode
& FMODE_READ
)) {
3003 struct trace_cpu
*tc
= inode
->i_private
;
3005 trace_array_put(tc
->tr
);
3011 trace_array_put(tr
);
3013 mutex_lock(&trace_types_lock
);
3015 for_each_tracing_cpu(cpu
) {
3016 if (iter
->buffer_iter
[cpu
])
3017 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
3020 if (iter
->trace
&& iter
->trace
->close
)
3021 iter
->trace
->close(iter
);
3023 if (!iter
->snapshot
)
3024 /* reenable tracing if it was previously enabled */
3025 tracing_start_tr(tr
);
3026 mutex_unlock(&trace_types_lock
);
3028 mutex_destroy(&iter
->mutex
);
3029 free_cpumask_var(iter
->started
);
3031 kfree(iter
->buffer_iter
);
3032 seq_release_private(inode
, file
);
3037 static int tracing_release_generic_tr(struct inode
*inode
, struct file
*file
)
3039 struct trace_array
*tr
= inode
->i_private
;
3041 trace_array_put(tr
);
3045 static int tracing_release_generic_tc(struct inode
*inode
, struct file
*file
)
3047 struct trace_cpu
*tc
= inode
->i_private
;
3048 struct trace_array
*tr
= tc
->tr
;
3050 trace_array_put(tr
);
3054 static int tracing_single_release_tr(struct inode
*inode
, struct file
*file
)
3056 struct trace_array
*tr
= inode
->i_private
;
3058 trace_array_put(tr
);
3060 return single_release(inode
, file
);
3063 static int tracing_open(struct inode
*inode
, struct file
*file
)
3065 struct trace_cpu
*tc
= inode
->i_private
;
3066 struct trace_array
*tr
= tc
->tr
;
3067 struct trace_iterator
*iter
;
3070 if (trace_array_get(tr
) < 0)
3073 /* If this file was open for write, then erase contents */
3074 if ((file
->f_mode
& FMODE_WRITE
) &&
3075 (file
->f_flags
& O_TRUNC
)) {
3076 if (tc
->cpu
== RING_BUFFER_ALL_CPUS
)
3077 tracing_reset_online_cpus(&tr
->trace_buffer
);
3079 tracing_reset(&tr
->trace_buffer
, tc
->cpu
);
3082 if (file
->f_mode
& FMODE_READ
) {
3083 iter
= __tracing_open(tr
, tc
, inode
, file
, false);
3085 ret
= PTR_ERR(iter
);
3086 else if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
3087 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
3091 trace_array_put(tr
);
3097 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
3099 struct tracer
*t
= v
;
3109 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
3114 mutex_lock(&trace_types_lock
);
3115 for (t
= trace_types
; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
3121 static void t_stop(struct seq_file
*m
, void *p
)
3123 mutex_unlock(&trace_types_lock
);
3126 static int t_show(struct seq_file
*m
, void *v
)
3128 struct tracer
*t
= v
;
3133 seq_printf(m
, "%s", t
->name
);
3142 static const struct seq_operations show_traces_seq_ops
= {
3149 static int show_traces_open(struct inode
*inode
, struct file
*file
)
3151 if (tracing_disabled
)
3154 return seq_open(file
, &show_traces_seq_ops
);
3158 tracing_write_stub(struct file
*filp
, const char __user
*ubuf
,
3159 size_t count
, loff_t
*ppos
)
3164 static loff_t
tracing_seek(struct file
*file
, loff_t offset
, int origin
)
3166 if (file
->f_mode
& FMODE_READ
)
3167 return seq_lseek(file
, offset
, origin
);
3172 static const struct file_operations tracing_fops
= {
3173 .open
= tracing_open
,
3175 .write
= tracing_write_stub
,
3176 .llseek
= tracing_seek
,
3177 .release
= tracing_release
,
3180 static const struct file_operations show_traces_fops
= {
3181 .open
= show_traces_open
,
3183 .release
= seq_release
,
3184 .llseek
= seq_lseek
,
3188 * Only trace on a CPU if the bitmask is set:
3190 static cpumask_var_t tracing_cpumask
;
3193 * The tracer itself will not take this lock, but still we want
3194 * to provide a consistent cpumask to user-space:
3196 static DEFINE_MUTEX(tracing_cpumask_update_lock
);
3199 * Temporary storage for the character representation of the
3200 * CPU bitmask (and one more byte for the newline):
3202 static char mask_str
[NR_CPUS
+ 1];
3205 tracing_cpumask_read(struct file
*filp
, char __user
*ubuf
,
3206 size_t count
, loff_t
*ppos
)
3210 mutex_lock(&tracing_cpumask_update_lock
);
3212 len
= cpumask_scnprintf(mask_str
, count
, tracing_cpumask
);
3213 if (count
- len
< 2) {
3217 len
+= sprintf(mask_str
+ len
, "\n");
3218 count
= simple_read_from_buffer(ubuf
, count
, ppos
, mask_str
, NR_CPUS
+1);
3221 mutex_unlock(&tracing_cpumask_update_lock
);
3227 tracing_cpumask_write(struct file
*filp
, const char __user
*ubuf
,
3228 size_t count
, loff_t
*ppos
)
3230 struct trace_array
*tr
= filp
->private_data
;
3231 cpumask_var_t tracing_cpumask_new
;
3234 if (!alloc_cpumask_var(&tracing_cpumask_new
, GFP_KERNEL
))
3237 err
= cpumask_parse_user(ubuf
, count
, tracing_cpumask_new
);
3241 mutex_lock(&tracing_cpumask_update_lock
);
3243 local_irq_disable();
3244 arch_spin_lock(&ftrace_max_lock
);
3245 for_each_tracing_cpu(cpu
) {
3247 * Increase/decrease the disabled counter if we are
3248 * about to flip a bit in the cpumask:
3250 if (cpumask_test_cpu(cpu
, tracing_cpumask
) &&
3251 !cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
3252 atomic_inc(&per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->disabled
);
3253 ring_buffer_record_disable_cpu(tr
->trace_buffer
.buffer
, cpu
);
3255 if (!cpumask_test_cpu(cpu
, tracing_cpumask
) &&
3256 cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
3257 atomic_dec(&per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->disabled
);
3258 ring_buffer_record_enable_cpu(tr
->trace_buffer
.buffer
, cpu
);
3261 arch_spin_unlock(&ftrace_max_lock
);
3264 cpumask_copy(tracing_cpumask
, tracing_cpumask_new
);
3266 mutex_unlock(&tracing_cpumask_update_lock
);
3267 free_cpumask_var(tracing_cpumask_new
);
3272 free_cpumask_var(tracing_cpumask_new
);
3277 static const struct file_operations tracing_cpumask_fops
= {
3278 .open
= tracing_open_generic
,
3279 .read
= tracing_cpumask_read
,
3280 .write
= tracing_cpumask_write
,
3281 .llseek
= generic_file_llseek
,
3284 static int tracing_trace_options_show(struct seq_file
*m
, void *v
)
3286 struct tracer_opt
*trace_opts
;
3287 struct trace_array
*tr
= m
->private;
3291 mutex_lock(&trace_types_lock
);
3292 tracer_flags
= tr
->current_trace
->flags
->val
;
3293 trace_opts
= tr
->current_trace
->flags
->opts
;
3295 for (i
= 0; trace_options
[i
]; i
++) {
3296 if (trace_flags
& (1 << i
))
3297 seq_printf(m
, "%s\n", trace_options
[i
]);
3299 seq_printf(m
, "no%s\n", trace_options
[i
]);
3302 for (i
= 0; trace_opts
[i
].name
; i
++) {
3303 if (tracer_flags
& trace_opts
[i
].bit
)
3304 seq_printf(m
, "%s\n", trace_opts
[i
].name
);
3306 seq_printf(m
, "no%s\n", trace_opts
[i
].name
);
3308 mutex_unlock(&trace_types_lock
);
3313 static int __set_tracer_option(struct tracer
*trace
,
3314 struct tracer_flags
*tracer_flags
,
3315 struct tracer_opt
*opts
, int neg
)
3319 ret
= trace
->set_flag(tracer_flags
->val
, opts
->bit
, !neg
);
3324 tracer_flags
->val
&= ~opts
->bit
;
3326 tracer_flags
->val
|= opts
->bit
;
3330 /* Try to assign a tracer specific option */
3331 static int set_tracer_option(struct tracer
*trace
, char *cmp
, int neg
)
3333 struct tracer_flags
*tracer_flags
= trace
->flags
;
3334 struct tracer_opt
*opts
= NULL
;
3337 for (i
= 0; tracer_flags
->opts
[i
].name
; i
++) {
3338 opts
= &tracer_flags
->opts
[i
];
3340 if (strcmp(cmp
, opts
->name
) == 0)
3341 return __set_tracer_option(trace
, trace
->flags
,
3348 /* Some tracers require overwrite to stay enabled */
3349 int trace_keep_overwrite(struct tracer
*tracer
, u32 mask
, int set
)
3351 if (tracer
->enabled
&& (mask
& TRACE_ITER_OVERWRITE
) && !set
)
3357 int set_tracer_flag(struct trace_array
*tr
, unsigned int mask
, int enabled
)
3359 /* do nothing if flag is already set */
3360 if (!!(trace_flags
& mask
) == !!enabled
)
3363 /* Give the tracer a chance to approve the change */
3364 if (tr
->current_trace
->flag_changed
)
3365 if (tr
->current_trace
->flag_changed(tr
->current_trace
, mask
, !!enabled
))
3369 trace_flags
|= mask
;
3371 trace_flags
&= ~mask
;
3373 if (mask
== TRACE_ITER_RECORD_CMD
)
3374 trace_event_enable_cmd_record(enabled
);
3376 if (mask
== TRACE_ITER_OVERWRITE
) {
3377 ring_buffer_change_overwrite(tr
->trace_buffer
.buffer
, enabled
);
3378 #ifdef CONFIG_TRACER_MAX_TRACE
3379 ring_buffer_change_overwrite(tr
->max_buffer
.buffer
, enabled
);
3383 if (mask
== TRACE_ITER_PRINTK
)
3384 trace_printk_start_stop_comm(enabled
);
3389 static int trace_set_options(struct trace_array
*tr
, char *option
)
3396 cmp
= strstrip(option
);
3398 if (strncmp(cmp
, "no", 2) == 0) {
3403 mutex_lock(&trace_types_lock
);
3405 for (i
= 0; trace_options
[i
]; i
++) {
3406 if (strcmp(cmp
, trace_options
[i
]) == 0) {
3407 ret
= set_tracer_flag(tr
, 1 << i
, !neg
);
3412 /* If no option could be set, test the specific tracer options */
3413 if (!trace_options
[i
])
3414 ret
= set_tracer_option(tr
->current_trace
, cmp
, neg
);
3416 mutex_unlock(&trace_types_lock
);
3422 tracing_trace_options_write(struct file
*filp
, const char __user
*ubuf
,
3423 size_t cnt
, loff_t
*ppos
)
3425 struct seq_file
*m
= filp
->private_data
;
3426 struct trace_array
*tr
= m
->private;
3430 if (cnt
>= sizeof(buf
))
3433 if (copy_from_user(&buf
, ubuf
, cnt
))
3438 ret
= trace_set_options(tr
, buf
);
3447 static int tracing_trace_options_open(struct inode
*inode
, struct file
*file
)
3449 struct trace_array
*tr
= inode
->i_private
;
3451 if (tracing_disabled
)
3454 if (trace_array_get(tr
) < 0)
3457 return single_open(file
, tracing_trace_options_show
, inode
->i_private
);
3460 static const struct file_operations tracing_iter_fops
= {
3461 .open
= tracing_trace_options_open
,
3463 .llseek
= seq_lseek
,
3464 .release
= tracing_single_release_tr
,
3465 .write
= tracing_trace_options_write
,
3468 static const char readme_msg
[] =
3469 "tracing mini-HOWTO:\n\n"
3470 "# echo 0 > tracing_on : quick way to disable tracing\n"
3471 "# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
3472 " Important files:\n"
3473 " trace\t\t\t- The static contents of the buffer\n"
3474 "\t\t\t To clear the buffer write into this file: echo > trace\n"
3475 " trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
3476 " current_tracer\t- function and latency tracers\n"
3477 " available_tracers\t- list of configured tracers for current_tracer\n"
3478 " buffer_size_kb\t- view and modify size of per cpu buffer\n"
3479 " buffer_total_size_kb - view total size of all cpu buffers\n\n"
3480 " trace_clock\t\t-change the clock used to order events\n"
3481 " local: Per cpu clock but may not be synced across CPUs\n"
3482 " global: Synced across CPUs but slows tracing down.\n"
3483 " counter: Not a clock, but just an increment\n"
3484 " uptime: Jiffy counter from time of boot\n"
3485 " perf: Same clock that perf events use\n"
3486 #ifdef CONFIG_X86_64
3487 " x86-tsc: TSC cycle counter\n"
3489 "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
3490 " tracing_cpumask\t- Limit which CPUs to trace\n"
3491 " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
3492 "\t\t\t Remove sub-buffer with rmdir\n"
3493 " trace_options\t\t- Set format or modify how tracing happens\n"
3494 "\t\t\t Disable an option by adding a suffix 'no' to the option name\n"
3495 #ifdef CONFIG_DYNAMIC_FTRACE
3496 "\n available_filter_functions - list of functions that can be filtered on\n"
3497 " set_ftrace_filter\t- echo function name in here to only trace these functions\n"
3498 " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3499 " modules: Can select a group via module\n"
3500 " Format: :mod:<module-name>\n"
3501 " example: echo :mod:ext3 > set_ftrace_filter\n"
3502 " triggers: a command to perform when function is hit\n"
3503 " Format: <function>:<trigger>[:count]\n"
3504 " trigger: traceon, traceoff\n"
3505 " enable_event:<system>:<event>\n"
3506 " disable_event:<system>:<event>\n"
3507 #ifdef CONFIG_STACKTRACE
3510 #ifdef CONFIG_TRACER_SNAPSHOT
3513 " example: echo do_fault:traceoff > set_ftrace_filter\n"
3514 " echo do_trap:traceoff:3 > set_ftrace_filter\n"
3515 " The first one will disable tracing every time do_fault is hit\n"
3516 " The second will disable tracing at most 3 times when do_trap is hit\n"
3517 " The first time do trap is hit and it disables tracing, the counter\n"
3518 " will decrement to 2. If tracing is already disabled, the counter\n"
3519 " will not decrement. It only decrements when the trigger did work\n"
3520 " To remove trigger without count:\n"
3521 " echo '!<function>:<trigger> > set_ftrace_filter\n"
3522 " To remove trigger with a count:\n"
3523 " echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
3524 " set_ftrace_notrace\t- echo function name in here to never trace.\n"
3525 " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3526 " modules: Can select a group via module command :mod:\n"
3527 " Does not accept triggers\n"
3528 #endif /* CONFIG_DYNAMIC_FTRACE */
3529 #ifdef CONFIG_FUNCTION_TRACER
3530 " set_ftrace_pid\t- Write pid(s) to only function trace those pids (function)\n"
3532 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3533 " set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
3534 " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
3536 #ifdef CONFIG_TRACER_SNAPSHOT
3537 "\n snapshot\t\t- Like 'trace' but shows the content of the static snapshot buffer\n"
3538 "\t\t\t Read the contents for more information\n"
3540 #ifdef CONFIG_STACKTRACE
3541 " stack_trace\t\t- Shows the max stack trace when active\n"
3542 " stack_max_size\t- Shows current max stack size that was traced\n"
3543 "\t\t\t Write into this file to reset the max size (trigger a new trace)\n"
3544 #ifdef CONFIG_DYNAMIC_FTRACE
3545 " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace traces\n"
3547 #endif /* CONFIG_STACKTRACE */
3551 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
3552 size_t cnt
, loff_t
*ppos
)
3554 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
3555 readme_msg
, strlen(readme_msg
));
3558 static const struct file_operations tracing_readme_fops
= {
3559 .open
= tracing_open_generic
,
3560 .read
= tracing_readme_read
,
3561 .llseek
= generic_file_llseek
,
3565 tracing_saved_cmdlines_read(struct file
*file
, char __user
*ubuf
,
3566 size_t cnt
, loff_t
*ppos
)
3575 file_buf
= kmalloc(SAVED_CMDLINES
*(16+TASK_COMM_LEN
), GFP_KERNEL
);
3579 buf_comm
= kmalloc(TASK_COMM_LEN
, GFP_KERNEL
);
3587 for (i
= 0; i
< SAVED_CMDLINES
; i
++) {
3590 pid
= map_cmdline_to_pid
[i
];
3591 if (pid
== -1 || pid
== NO_CMDLINE_MAP
)
3594 trace_find_cmdline(pid
, buf_comm
);
3595 r
= sprintf(buf
, "%d %s\n", pid
, buf_comm
);
3600 len
= simple_read_from_buffer(ubuf
, cnt
, ppos
,
3609 static const struct file_operations tracing_saved_cmdlines_fops
= {
3610 .open
= tracing_open_generic
,
3611 .read
= tracing_saved_cmdlines_read
,
3612 .llseek
= generic_file_llseek
,
3616 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
3617 size_t cnt
, loff_t
*ppos
)
3619 struct trace_array
*tr
= filp
->private_data
;
3620 char buf
[MAX_TRACER_SIZE
+2];
3623 mutex_lock(&trace_types_lock
);
3624 r
= sprintf(buf
, "%s\n", tr
->current_trace
->name
);
3625 mutex_unlock(&trace_types_lock
);
3627 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3630 int tracer_init(struct tracer
*t
, struct trace_array
*tr
)
3632 tracing_reset_online_cpus(&tr
->trace_buffer
);
3636 static void set_buffer_entries(struct trace_buffer
*buf
, unsigned long val
)
3640 for_each_tracing_cpu(cpu
)
3641 per_cpu_ptr(buf
->data
, cpu
)->entries
= val
;
3644 #ifdef CONFIG_TRACER_MAX_TRACE
3645 /* resize @tr's buffer to the size of @size_tr's entries */
3646 static int resize_buffer_duplicate_size(struct trace_buffer
*trace_buf
,
3647 struct trace_buffer
*size_buf
, int cpu_id
)
3651 if (cpu_id
== RING_BUFFER_ALL_CPUS
) {
3652 for_each_tracing_cpu(cpu
) {
3653 ret
= ring_buffer_resize(trace_buf
->buffer
,
3654 per_cpu_ptr(size_buf
->data
, cpu
)->entries
, cpu
);
3657 per_cpu_ptr(trace_buf
->data
, cpu
)->entries
=
3658 per_cpu_ptr(size_buf
->data
, cpu
)->entries
;
3661 ret
= ring_buffer_resize(trace_buf
->buffer
,
3662 per_cpu_ptr(size_buf
->data
, cpu_id
)->entries
, cpu_id
);
3664 per_cpu_ptr(trace_buf
->data
, cpu_id
)->entries
=
3665 per_cpu_ptr(size_buf
->data
, cpu_id
)->entries
;
3670 #endif /* CONFIG_TRACER_MAX_TRACE */
3672 static int __tracing_resize_ring_buffer(struct trace_array
*tr
,
3673 unsigned long size
, int cpu
)
3678 * If kernel or user changes the size of the ring buffer
3679 * we use the size that was given, and we can forget about
3680 * expanding it later.
3682 ring_buffer_expanded
= true;
3684 /* May be called before buffers are initialized */
3685 if (!tr
->trace_buffer
.buffer
)
3688 ret
= ring_buffer_resize(tr
->trace_buffer
.buffer
, size
, cpu
);
3692 #ifdef CONFIG_TRACER_MAX_TRACE
3693 if (!(tr
->flags
& TRACE_ARRAY_FL_GLOBAL
) ||
3694 !tr
->current_trace
->use_max_tr
)
3697 ret
= ring_buffer_resize(tr
->max_buffer
.buffer
, size
, cpu
);
3699 int r
= resize_buffer_duplicate_size(&tr
->trace_buffer
,
3700 &tr
->trace_buffer
, cpu
);
3703 * AARGH! We are left with different
3704 * size max buffer!!!!
3705 * The max buffer is our "snapshot" buffer.
3706 * When a tracer needs a snapshot (one of the
3707 * latency tracers), it swaps the max buffer
3708 * with the saved snap shot. We succeeded to
3709 * update the size of the main buffer, but failed to
3710 * update the size of the max buffer. But when we tried
3711 * to reset the main buffer to the original size, we
3712 * failed there too. This is very unlikely to
3713 * happen, but if it does, warn and kill all
3717 tracing_disabled
= 1;
3722 if (cpu
== RING_BUFFER_ALL_CPUS
)
3723 set_buffer_entries(&tr
->max_buffer
, size
);
3725 per_cpu_ptr(tr
->max_buffer
.data
, cpu
)->entries
= size
;
3728 #endif /* CONFIG_TRACER_MAX_TRACE */
3730 if (cpu
== RING_BUFFER_ALL_CPUS
)
3731 set_buffer_entries(&tr
->trace_buffer
, size
);
3733 per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
= size
;
3738 static ssize_t
tracing_resize_ring_buffer(struct trace_array
*tr
,
3739 unsigned long size
, int cpu_id
)
3743 mutex_lock(&trace_types_lock
);
3745 if (cpu_id
!= RING_BUFFER_ALL_CPUS
) {
3746 /* make sure, this cpu is enabled in the mask */
3747 if (!cpumask_test_cpu(cpu_id
, tracing_buffer_mask
)) {
3753 ret
= __tracing_resize_ring_buffer(tr
, size
, cpu_id
);
3758 mutex_unlock(&trace_types_lock
);
3765 * tracing_update_buffers - used by tracing facility to expand ring buffers
3767 * To save on memory when the tracing is never used on a system with it
3768 * configured in. The ring buffers are set to a minimum size. But once
3769 * a user starts to use the tracing facility, then they need to grow
3770 * to their default size.
3772 * This function is to be called when a tracer is about to be used.
3774 int tracing_update_buffers(void)
3778 mutex_lock(&trace_types_lock
);
3779 if (!ring_buffer_expanded
)
3780 ret
= __tracing_resize_ring_buffer(&global_trace
, trace_buf_size
,
3781 RING_BUFFER_ALL_CPUS
);
3782 mutex_unlock(&trace_types_lock
);
3787 struct trace_option_dentry
;
3789 static struct trace_option_dentry
*
3790 create_trace_option_files(struct trace_array
*tr
, struct tracer
*tracer
);
3793 destroy_trace_option_files(struct trace_option_dentry
*topts
);
3795 static int tracing_set_tracer(const char *buf
)
3797 static struct trace_option_dentry
*topts
;
3798 struct trace_array
*tr
= &global_trace
;
3800 #ifdef CONFIG_TRACER_MAX_TRACE
3805 mutex_lock(&trace_types_lock
);
3807 if (!ring_buffer_expanded
) {
3808 ret
= __tracing_resize_ring_buffer(tr
, trace_buf_size
,
3809 RING_BUFFER_ALL_CPUS
);
3815 for (t
= trace_types
; t
; t
= t
->next
) {
3816 if (strcmp(t
->name
, buf
) == 0)
3823 if (t
== tr
->current_trace
)
3826 trace_branch_disable();
3828 tr
->current_trace
->enabled
= false;
3830 if (tr
->current_trace
->reset
)
3831 tr
->current_trace
->reset(tr
);
3833 /* Current trace needs to be nop_trace before synchronize_sched */
3834 tr
->current_trace
= &nop_trace
;
3836 #ifdef CONFIG_TRACER_MAX_TRACE
3837 had_max_tr
= tr
->allocated_snapshot
;
3839 if (had_max_tr
&& !t
->use_max_tr
) {
3841 * We need to make sure that the update_max_tr sees that
3842 * current_trace changed to nop_trace to keep it from
3843 * swapping the buffers after we resize it.
3844 * The update_max_tr is called from interrupts disabled
3845 * so a synchronized_sched() is sufficient.
3847 synchronize_sched();
3851 destroy_trace_option_files(topts
);
3853 topts
= create_trace_option_files(tr
, t
);
3855 #ifdef CONFIG_TRACER_MAX_TRACE
3856 if (t
->use_max_tr
&& !had_max_tr
) {
3857 ret
= alloc_snapshot(tr
);
3864 ret
= tracer_init(t
, tr
);
3869 tr
->current_trace
= t
;
3870 tr
->current_trace
->enabled
= true;
3871 trace_branch_enable(tr
);
3873 mutex_unlock(&trace_types_lock
);
3879 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
3880 size_t cnt
, loff_t
*ppos
)
3882 char buf
[MAX_TRACER_SIZE
+1];
3889 if (cnt
> MAX_TRACER_SIZE
)
3890 cnt
= MAX_TRACER_SIZE
;
3892 if (copy_from_user(&buf
, ubuf
, cnt
))
3897 /* strip ending whitespace. */
3898 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
3901 err
= tracing_set_tracer(buf
);
3911 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
3912 size_t cnt
, loff_t
*ppos
)
3914 unsigned long *ptr
= filp
->private_data
;
3918 r
= snprintf(buf
, sizeof(buf
), "%ld\n",
3919 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
3920 if (r
> sizeof(buf
))
3922 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3926 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
3927 size_t cnt
, loff_t
*ppos
)
3929 unsigned long *ptr
= filp
->private_data
;
3933 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
3942 static int tracing_open_pipe(struct inode
*inode
, struct file
*filp
)
3944 struct trace_cpu
*tc
= inode
->i_private
;
3945 struct trace_array
*tr
= tc
->tr
;
3946 struct trace_iterator
*iter
;
3949 if (tracing_disabled
)
3952 if (trace_array_get(tr
) < 0)
3955 mutex_lock(&trace_types_lock
);
3957 /* create a buffer to store the information to pass to userspace */
3958 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
3965 * We make a copy of the current tracer to avoid concurrent
3966 * changes on it while we are reading.
3968 iter
->trace
= kmalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
3973 *iter
->trace
= *tr
->current_trace
;
3975 if (!alloc_cpumask_var(&iter
->started
, GFP_KERNEL
)) {
3980 /* trace pipe does not show start of buffer */
3981 cpumask_setall(iter
->started
);
3983 if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
3984 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
3986 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
3987 if (trace_clocks
[tr
->clock_id
].in_ns
)
3988 iter
->iter_flags
|= TRACE_FILE_TIME_IN_NS
;
3990 iter
->cpu_file
= tc
->cpu
;
3992 iter
->trace_buffer
= &tc
->tr
->trace_buffer
;
3993 mutex_init(&iter
->mutex
);
3994 filp
->private_data
= iter
;
3996 if (iter
->trace
->pipe_open
)
3997 iter
->trace
->pipe_open(iter
);
3999 nonseekable_open(inode
, filp
);
4001 mutex_unlock(&trace_types_lock
);
4007 __trace_array_put(tr
);
4008 mutex_unlock(&trace_types_lock
);
4012 static int tracing_release_pipe(struct inode
*inode
, struct file
*file
)
4014 struct trace_iterator
*iter
= file
->private_data
;
4015 struct trace_cpu
*tc
= inode
->i_private
;
4016 struct trace_array
*tr
= tc
->tr
;
4018 mutex_lock(&trace_types_lock
);
4020 if (iter
->trace
->pipe_close
)
4021 iter
->trace
->pipe_close(iter
);
4023 mutex_unlock(&trace_types_lock
);
4025 free_cpumask_var(iter
->started
);
4026 mutex_destroy(&iter
->mutex
);
4030 trace_array_put(tr
);
4036 trace_poll(struct trace_iterator
*iter
, struct file
*filp
, poll_table
*poll_table
)
4038 /* Iterators are static, they should be filled or empty */
4039 if (trace_buffer_iter(iter
, iter
->cpu_file
))
4040 return POLLIN
| POLLRDNORM
;
4042 if (trace_flags
& TRACE_ITER_BLOCK
)
4044 * Always select as readable when in blocking mode
4046 return POLLIN
| POLLRDNORM
;
4048 return ring_buffer_poll_wait(iter
->trace_buffer
->buffer
, iter
->cpu_file
,
4053 tracing_poll_pipe(struct file
*filp
, poll_table
*poll_table
)
4055 struct trace_iterator
*iter
= filp
->private_data
;
4057 return trace_poll(iter
, filp
, poll_table
);
4061 * This is a make-shift waitqueue.
4062 * A tracer might use this callback on some rare cases:
4064 * 1) the current tracer might hold the runqueue lock when it wakes up
4065 * a reader, hence a deadlock (sched, function, and function graph tracers)
4066 * 2) the function tracers, trace all functions, we don't want
4067 * the overhead of calling wake_up and friends
4068 * (and tracing them too)
4070 * Anyway, this is really very primitive wakeup.
4072 void poll_wait_pipe(struct trace_iterator
*iter
)
4074 set_current_state(TASK_INTERRUPTIBLE
);
4075 /* sleep for 100 msecs, and try again. */
4076 schedule_timeout(HZ
/ 10);
4079 /* Must be called with trace_types_lock mutex held. */
4080 static int tracing_wait_pipe(struct file
*filp
)
4082 struct trace_iterator
*iter
= filp
->private_data
;
4084 while (trace_empty(iter
)) {
4086 if ((filp
->f_flags
& O_NONBLOCK
)) {
4090 mutex_unlock(&iter
->mutex
);
4092 iter
->trace
->wait_pipe(iter
);
4094 mutex_lock(&iter
->mutex
);
4096 if (signal_pending(current
))
4100 * We block until we read something and tracing is disabled.
4101 * We still block if tracing is disabled, but we have never
4102 * read anything. This allows a user to cat this file, and
4103 * then enable tracing. But after we have read something,
4104 * we give an EOF when tracing is again disabled.
4106 * iter->pos will be 0 if we haven't read anything.
4108 if (!tracing_is_on() && iter
->pos
)
4119 tracing_read_pipe(struct file
*filp
, char __user
*ubuf
,
4120 size_t cnt
, loff_t
*ppos
)
4122 struct trace_iterator
*iter
= filp
->private_data
;
4123 struct trace_array
*tr
= iter
->tr
;
4126 /* return any leftover data */
4127 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
4131 trace_seq_init(&iter
->seq
);
4133 /* copy the tracer to avoid using a global lock all around */
4134 mutex_lock(&trace_types_lock
);
4135 if (unlikely(iter
->trace
->name
!= tr
->current_trace
->name
))
4136 *iter
->trace
= *tr
->current_trace
;
4137 mutex_unlock(&trace_types_lock
);
4140 * Avoid more than one consumer on a single file descriptor
4141 * This is just a matter of traces coherency, the ring buffer itself
4144 mutex_lock(&iter
->mutex
);
4145 if (iter
->trace
->read
) {
4146 sret
= iter
->trace
->read(iter
, filp
, ubuf
, cnt
, ppos
);
4152 sret
= tracing_wait_pipe(filp
);
4156 /* stop when tracing is finished */
4157 if (trace_empty(iter
)) {
4162 if (cnt
>= PAGE_SIZE
)
4163 cnt
= PAGE_SIZE
- 1;
4165 /* reset all but tr, trace, and overruns */
4166 memset(&iter
->seq
, 0,
4167 sizeof(struct trace_iterator
) -
4168 offsetof(struct trace_iterator
, seq
));
4171 trace_event_read_lock();
4172 trace_access_lock(iter
->cpu_file
);
4173 while (trace_find_next_entry_inc(iter
) != NULL
) {
4174 enum print_line_t ret
;
4175 int len
= iter
->seq
.len
;
4177 ret
= print_trace_line(iter
);
4178 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
4179 /* don't print partial lines */
4180 iter
->seq
.len
= len
;
4183 if (ret
!= TRACE_TYPE_NO_CONSUME
)
4184 trace_consume(iter
);
4186 if (iter
->seq
.len
>= cnt
)
4190 * Setting the full flag means we reached the trace_seq buffer
4191 * size and we should leave by partial output condition above.
4192 * One of the trace_seq_* functions is not used properly.
4194 WARN_ONCE(iter
->seq
.full
, "full flag set for trace type %d",
4197 trace_access_unlock(iter
->cpu_file
);
4198 trace_event_read_unlock();
4200 /* Now copy what we have to the user */
4201 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
4202 if (iter
->seq
.readpos
>= iter
->seq
.len
)
4203 trace_seq_init(&iter
->seq
);
4206 * If there was nothing to send to user, in spite of consuming trace
4207 * entries, go back to wait for more entries.
4213 mutex_unlock(&iter
->mutex
);
4218 static void tracing_pipe_buf_release(struct pipe_inode_info
*pipe
,
4219 struct pipe_buffer
*buf
)
4221 __free_page(buf
->page
);
4224 static void tracing_spd_release_pipe(struct splice_pipe_desc
*spd
,
4227 __free_page(spd
->pages
[idx
]);
4230 static const struct pipe_buf_operations tracing_pipe_buf_ops
= {
4232 .map
= generic_pipe_buf_map
,
4233 .unmap
= generic_pipe_buf_unmap
,
4234 .confirm
= generic_pipe_buf_confirm
,
4235 .release
= tracing_pipe_buf_release
,
4236 .steal
= generic_pipe_buf_steal
,
4237 .get
= generic_pipe_buf_get
,
4241 tracing_fill_pipe_page(size_t rem
, struct trace_iterator
*iter
)
4246 /* Seq buffer is page-sized, exactly what we need. */
4248 count
= iter
->seq
.len
;
4249 ret
= print_trace_line(iter
);
4250 count
= iter
->seq
.len
- count
;
4253 iter
->seq
.len
-= count
;
4256 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
4257 iter
->seq
.len
-= count
;
4261 if (ret
!= TRACE_TYPE_NO_CONSUME
)
4262 trace_consume(iter
);
4264 if (!trace_find_next_entry_inc(iter
)) {
4274 static ssize_t
tracing_splice_read_pipe(struct file
*filp
,
4276 struct pipe_inode_info
*pipe
,
4280 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
4281 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
4282 struct trace_iterator
*iter
= filp
->private_data
;
4283 struct splice_pipe_desc spd
= {
4285 .partial
= partial_def
,
4286 .nr_pages
= 0, /* This gets updated below. */
4287 .nr_pages_max
= PIPE_DEF_BUFFERS
,
4289 .ops
= &tracing_pipe_buf_ops
,
4290 .spd_release
= tracing_spd_release_pipe
,
4292 struct trace_array
*tr
= iter
->tr
;
4297 if (splice_grow_spd(pipe
, &spd
))
4300 /* copy the tracer to avoid using a global lock all around */
4301 mutex_lock(&trace_types_lock
);
4302 if (unlikely(iter
->trace
->name
!= tr
->current_trace
->name
))
4303 *iter
->trace
= *tr
->current_trace
;
4304 mutex_unlock(&trace_types_lock
);
4306 mutex_lock(&iter
->mutex
);
4308 if (iter
->trace
->splice_read
) {
4309 ret
= iter
->trace
->splice_read(iter
, filp
,
4310 ppos
, pipe
, len
, flags
);
4315 ret
= tracing_wait_pipe(filp
);
4319 if (!iter
->ent
&& !trace_find_next_entry_inc(iter
)) {
4324 trace_event_read_lock();
4325 trace_access_lock(iter
->cpu_file
);
4327 /* Fill as many pages as possible. */
4328 for (i
= 0, rem
= len
; i
< pipe
->buffers
&& rem
; i
++) {
4329 spd
.pages
[i
] = alloc_page(GFP_KERNEL
);
4333 rem
= tracing_fill_pipe_page(rem
, iter
);
4335 /* Copy the data into the page, so we can start over. */
4336 ret
= trace_seq_to_buffer(&iter
->seq
,
4337 page_address(spd
.pages
[i
]),
4340 __free_page(spd
.pages
[i
]);
4343 spd
.partial
[i
].offset
= 0;
4344 spd
.partial
[i
].len
= iter
->seq
.len
;
4346 trace_seq_init(&iter
->seq
);
4349 trace_access_unlock(iter
->cpu_file
);
4350 trace_event_read_unlock();
4351 mutex_unlock(&iter
->mutex
);
4355 ret
= splice_to_pipe(pipe
, &spd
);
4357 splice_shrink_spd(&spd
);
4361 mutex_unlock(&iter
->mutex
);
4366 tracing_entries_read(struct file
*filp
, char __user
*ubuf
,
4367 size_t cnt
, loff_t
*ppos
)
4369 struct trace_cpu
*tc
= filp
->private_data
;
4370 struct trace_array
*tr
= tc
->tr
;
4375 mutex_lock(&trace_types_lock
);
4377 if (tc
->cpu
== RING_BUFFER_ALL_CPUS
) {
4378 int cpu
, buf_size_same
;
4383 /* check if all cpu sizes are same */
4384 for_each_tracing_cpu(cpu
) {
4385 /* fill in the size from first enabled cpu */
4387 size
= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
;
4388 if (size
!= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
) {
4394 if (buf_size_same
) {
4395 if (!ring_buffer_expanded
)
4396 r
= sprintf(buf
, "%lu (expanded: %lu)\n",
4398 trace_buf_size
>> 10);
4400 r
= sprintf(buf
, "%lu\n", size
>> 10);
4402 r
= sprintf(buf
, "X\n");
4404 r
= sprintf(buf
, "%lu\n", per_cpu_ptr(tr
->trace_buffer
.data
, tc
->cpu
)->entries
>> 10);
4406 mutex_unlock(&trace_types_lock
);
4408 ret
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
4413 tracing_entries_write(struct file
*filp
, const char __user
*ubuf
,
4414 size_t cnt
, loff_t
*ppos
)
4416 struct trace_cpu
*tc
= filp
->private_data
;
4420 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
4424 /* must have at least 1 entry */
4428 /* value is in KB */
4431 ret
= tracing_resize_ring_buffer(tc
->tr
, val
, tc
->cpu
);
4441 tracing_total_entries_read(struct file
*filp
, char __user
*ubuf
,
4442 size_t cnt
, loff_t
*ppos
)
4444 struct trace_array
*tr
= filp
->private_data
;
4447 unsigned long size
= 0, expanded_size
= 0;
4449 mutex_lock(&trace_types_lock
);
4450 for_each_tracing_cpu(cpu
) {
4451 size
+= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
>> 10;
4452 if (!ring_buffer_expanded
)
4453 expanded_size
+= trace_buf_size
>> 10;
4455 if (ring_buffer_expanded
)
4456 r
= sprintf(buf
, "%lu\n", size
);
4458 r
= sprintf(buf
, "%lu (expanded: %lu)\n", size
, expanded_size
);
4459 mutex_unlock(&trace_types_lock
);
4461 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
4465 tracing_free_buffer_write(struct file
*filp
, const char __user
*ubuf
,
4466 size_t cnt
, loff_t
*ppos
)
4469 * There is no need to read what the user has written, this function
4470 * is just to make sure that there is no error when "echo" is used
4479 tracing_free_buffer_release(struct inode
*inode
, struct file
*filp
)
4481 struct trace_array
*tr
= inode
->i_private
;
4483 /* disable tracing ? */
4484 if (trace_flags
& TRACE_ITER_STOP_ON_FREE
)
4486 /* resize the ring buffer to 0 */
4487 tracing_resize_ring_buffer(tr
, 0, RING_BUFFER_ALL_CPUS
);
4489 trace_array_put(tr
);
4495 tracing_mark_write(struct file
*filp
, const char __user
*ubuf
,
4496 size_t cnt
, loff_t
*fpos
)
4498 unsigned long addr
= (unsigned long)ubuf
;
4499 struct trace_array
*tr
= filp
->private_data
;
4500 struct ring_buffer_event
*event
;
4501 struct ring_buffer
*buffer
;
4502 struct print_entry
*entry
;
4503 unsigned long irq_flags
;
4504 struct page
*pages
[2];
4514 if (tracing_disabled
)
4517 if (!(trace_flags
& TRACE_ITER_MARKERS
))
4520 if (cnt
> TRACE_BUF_SIZE
)
4521 cnt
= TRACE_BUF_SIZE
;
4524 * Userspace is injecting traces into the kernel trace buffer.
4525 * We want to be as non intrusive as possible.
4526 * To do so, we do not want to allocate any special buffers
4527 * or take any locks, but instead write the userspace data
4528 * straight into the ring buffer.
4530 * First we need to pin the userspace buffer into memory,
4531 * which, most likely it is, because it just referenced it.
4532 * But there's no guarantee that it is. By using get_user_pages_fast()
4533 * and kmap_atomic/kunmap_atomic() we can get access to the
4534 * pages directly. We then write the data directly into the
4537 BUILD_BUG_ON(TRACE_BUF_SIZE
>= PAGE_SIZE
);
4539 /* check if we cross pages */
4540 if ((addr
& PAGE_MASK
) != ((addr
+ cnt
) & PAGE_MASK
))
4543 offset
= addr
& (PAGE_SIZE
- 1);
4546 ret
= get_user_pages_fast(addr
, nr_pages
, 0, pages
);
4547 if (ret
< nr_pages
) {
4549 put_page(pages
[ret
]);
4554 for (i
= 0; i
< nr_pages
; i
++)
4555 map_page
[i
] = kmap_atomic(pages
[i
]);
4557 local_save_flags(irq_flags
);
4558 size
= sizeof(*entry
) + cnt
+ 2; /* possible \n added */
4559 buffer
= tr
->trace_buffer
.buffer
;
4560 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, size
,
4561 irq_flags
, preempt_count());
4563 /* Ring buffer disabled, return as if not open for write */
4568 entry
= ring_buffer_event_data(event
);
4569 entry
->ip
= _THIS_IP_
;
4571 if (nr_pages
== 2) {
4572 len
= PAGE_SIZE
- offset
;
4573 memcpy(&entry
->buf
, map_page
[0] + offset
, len
);
4574 memcpy(&entry
->buf
[len
], map_page
[1], cnt
- len
);
4576 memcpy(&entry
->buf
, map_page
[0] + offset
, cnt
);
4578 if (entry
->buf
[cnt
- 1] != '\n') {
4579 entry
->buf
[cnt
] = '\n';
4580 entry
->buf
[cnt
+ 1] = '\0';
4582 entry
->buf
[cnt
] = '\0';
4584 __buffer_unlock_commit(buffer
, event
);
4591 for (i
= 0; i
< nr_pages
; i
++){
4592 kunmap_atomic(map_page
[i
]);
4599 static int tracing_clock_show(struct seq_file
*m
, void *v
)
4601 struct trace_array
*tr
= m
->private;
4604 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++)
4606 "%s%s%s%s", i
? " " : "",
4607 i
== tr
->clock_id
? "[" : "", trace_clocks
[i
].name
,
4608 i
== tr
->clock_id
? "]" : "");
4614 static ssize_t
tracing_clock_write(struct file
*filp
, const char __user
*ubuf
,
4615 size_t cnt
, loff_t
*fpos
)
4617 struct seq_file
*m
= filp
->private_data
;
4618 struct trace_array
*tr
= m
->private;
4620 const char *clockstr
;
4623 if (cnt
>= sizeof(buf
))
4626 if (copy_from_user(&buf
, ubuf
, cnt
))
4631 clockstr
= strstrip(buf
);
4633 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++) {
4634 if (strcmp(trace_clocks
[i
].name
, clockstr
) == 0)
4637 if (i
== ARRAY_SIZE(trace_clocks
))
4640 mutex_lock(&trace_types_lock
);
4644 ring_buffer_set_clock(tr
->trace_buffer
.buffer
, trace_clocks
[i
].func
);
4647 * New clock may not be consistent with the previous clock.
4648 * Reset the buffer so that it doesn't have incomparable timestamps.
4650 tracing_reset_online_cpus(&global_trace
.trace_buffer
);
4652 #ifdef CONFIG_TRACER_MAX_TRACE
4653 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
&& tr
->max_buffer
.buffer
)
4654 ring_buffer_set_clock(tr
->max_buffer
.buffer
, trace_clocks
[i
].func
);
4655 tracing_reset_online_cpus(&global_trace
.max_buffer
);
4658 mutex_unlock(&trace_types_lock
);
4665 static int tracing_clock_open(struct inode
*inode
, struct file
*file
)
4667 struct trace_array
*tr
= inode
->i_private
;
4670 if (tracing_disabled
)
4673 if (trace_array_get(tr
))
4676 ret
= single_open(file
, tracing_clock_show
, inode
->i_private
);
4678 trace_array_put(tr
);
4683 struct ftrace_buffer_info
{
4684 struct trace_iterator iter
;
4689 #ifdef CONFIG_TRACER_SNAPSHOT
4690 static int tracing_snapshot_open(struct inode
*inode
, struct file
*file
)
4692 struct trace_cpu
*tc
= inode
->i_private
;
4693 struct trace_array
*tr
= tc
->tr
;
4694 struct trace_iterator
*iter
;
4698 if (trace_array_get(tr
) < 0)
4701 if (file
->f_mode
& FMODE_READ
) {
4702 iter
= __tracing_open(tr
, tc
, inode
, file
, true);
4704 ret
= PTR_ERR(iter
);
4706 /* Writes still need the seq_file to hold the private data */
4707 m
= kzalloc(sizeof(*m
), GFP_KERNEL
);
4710 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
4716 iter
->trace_buffer
= &tc
->tr
->max_buffer
;
4717 iter
->cpu_file
= tc
->cpu
;
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_tc
,
4877 .read
= tracing_entries_read
,
4878 .write
= tracing_entries_write
,
4879 .llseek
= generic_file_llseek
,
4880 .release
= tracing_release_generic_tc
,
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_cpu
*tc
= inode
->i_private
;
4933 struct trace_array
*tr
= tc
->tr
;
4934 struct ftrace_buffer_info
*info
;
4937 if (tracing_disabled
)
4940 if (trace_array_get(tr
) < 0)
4943 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
4945 trace_array_put(tr
);
4949 mutex_lock(&trace_types_lock
);
4954 info
->iter
.cpu_file
= tc
->cpu
;
4955 info
->iter
.trace
= tr
->current_trace
;
4956 info
->iter
.trace_buffer
= &tr
->trace_buffer
;
4958 /* Force reading ring buffer for first read */
4959 info
->read
= (unsigned int)-1;
4961 filp
->private_data
= info
;
4963 mutex_unlock(&trace_types_lock
);
4965 ret
= nonseekable_open(inode
, filp
);
4967 trace_array_put(tr
);
4973 tracing_buffers_poll(struct file
*filp
, poll_table
*poll_table
)
4975 struct ftrace_buffer_info
*info
= filp
->private_data
;
4976 struct trace_iterator
*iter
= &info
->iter
;
4978 return trace_poll(iter
, filp
, poll_table
);
4982 tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
4983 size_t count
, loff_t
*ppos
)
4985 struct ftrace_buffer_info
*info
= filp
->private_data
;
4986 struct trace_iterator
*iter
= &info
->iter
;
4993 mutex_lock(&trace_types_lock
);
4995 #ifdef CONFIG_TRACER_MAX_TRACE
4996 if (iter
->snapshot
&& iter
->tr
->current_trace
->use_max_tr
) {
5003 info
->spare
= ring_buffer_alloc_read_page(iter
->trace_buffer
->buffer
,
5009 /* Do we have previous read data to read? */
5010 if (info
->read
< PAGE_SIZE
)
5014 trace_access_lock(iter
->cpu_file
);
5015 ret
= ring_buffer_read_page(iter
->trace_buffer
->buffer
,
5019 trace_access_unlock(iter
->cpu_file
);
5022 if (trace_empty(iter
)) {
5023 if ((filp
->f_flags
& O_NONBLOCK
)) {
5027 mutex_unlock(&trace_types_lock
);
5028 iter
->trace
->wait_pipe(iter
);
5029 mutex_lock(&trace_types_lock
);
5030 if (signal_pending(current
)) {
5042 size
= PAGE_SIZE
- info
->read
;
5046 ret
= copy_to_user(ubuf
, info
->spare
+ info
->read
, size
);
5057 mutex_unlock(&trace_types_lock
);
5062 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
)
5064 struct ftrace_buffer_info
*info
= file
->private_data
;
5065 struct trace_iterator
*iter
= &info
->iter
;
5067 mutex_lock(&trace_types_lock
);
5069 __trace_array_put(iter
->tr
);
5072 ring_buffer_free_read_page(iter
->trace_buffer
->buffer
, info
->spare
);
5075 mutex_unlock(&trace_types_lock
);
5081 struct ring_buffer
*buffer
;
5086 static void buffer_pipe_buf_release(struct pipe_inode_info
*pipe
,
5087 struct pipe_buffer
*buf
)
5089 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
5094 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
5099 static void buffer_pipe_buf_get(struct pipe_inode_info
*pipe
,
5100 struct pipe_buffer
*buf
)
5102 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
5107 /* Pipe buffer operations for a buffer. */
5108 static const struct pipe_buf_operations buffer_pipe_buf_ops
= {
5110 .map
= generic_pipe_buf_map
,
5111 .unmap
= generic_pipe_buf_unmap
,
5112 .confirm
= generic_pipe_buf_confirm
,
5113 .release
= buffer_pipe_buf_release
,
5114 .steal
= generic_pipe_buf_steal
,
5115 .get
= buffer_pipe_buf_get
,
5119 * Callback from splice_to_pipe(), if we need to release some pages
5120 * at the end of the spd in case we error'ed out in filling the pipe.
5122 static void buffer_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
5124 struct buffer_ref
*ref
=
5125 (struct buffer_ref
*)spd
->partial
[i
].private;
5130 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
5132 spd
->partial
[i
].private = 0;
5136 tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
5137 struct pipe_inode_info
*pipe
, size_t len
,
5140 struct ftrace_buffer_info
*info
= file
->private_data
;
5141 struct trace_iterator
*iter
= &info
->iter
;
5142 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
5143 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
5144 struct splice_pipe_desc spd
= {
5146 .partial
= partial_def
,
5147 .nr_pages_max
= PIPE_DEF_BUFFERS
,
5149 .ops
= &buffer_pipe_buf_ops
,
5150 .spd_release
= buffer_spd_release
,
5152 struct buffer_ref
*ref
;
5153 int entries
, size
, i
;
5156 mutex_lock(&trace_types_lock
);
5158 #ifdef CONFIG_TRACER_MAX_TRACE
5159 if (iter
->snapshot
&& iter
->tr
->current_trace
->use_max_tr
) {
5165 if (splice_grow_spd(pipe
, &spd
)) {
5170 if (*ppos
& (PAGE_SIZE
- 1)) {
5175 if (len
& (PAGE_SIZE
- 1)) {
5176 if (len
< PAGE_SIZE
) {
5184 trace_access_lock(iter
->cpu_file
);
5185 entries
= ring_buffer_entries_cpu(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
5187 for (i
= 0; i
< pipe
->buffers
&& len
&& entries
; i
++, len
-= PAGE_SIZE
) {
5191 ref
= kzalloc(sizeof(*ref
), GFP_KERNEL
);
5196 ref
->buffer
= iter
->trace_buffer
->buffer
;
5197 ref
->page
= ring_buffer_alloc_read_page(ref
->buffer
, iter
->cpu_file
);
5203 r
= ring_buffer_read_page(ref
->buffer
, &ref
->page
,
5204 len
, iter
->cpu_file
, 1);
5206 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
5212 * zero out any left over data, this is going to
5215 size
= ring_buffer_page_len(ref
->page
);
5216 if (size
< PAGE_SIZE
)
5217 memset(ref
->page
+ size
, 0, PAGE_SIZE
- size
);
5219 page
= virt_to_page(ref
->page
);
5221 spd
.pages
[i
] = page
;
5222 spd
.partial
[i
].len
= PAGE_SIZE
;
5223 spd
.partial
[i
].offset
= 0;
5224 spd
.partial
[i
].private = (unsigned long)ref
;
5228 entries
= ring_buffer_entries_cpu(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
5231 trace_access_unlock(iter
->cpu_file
);
5234 /* did we read anything? */
5235 if (!spd
.nr_pages
) {
5236 if ((file
->f_flags
& O_NONBLOCK
) || (flags
& SPLICE_F_NONBLOCK
)) {
5240 mutex_unlock(&trace_types_lock
);
5241 iter
->trace
->wait_pipe(iter
);
5242 mutex_lock(&trace_types_lock
);
5243 if (signal_pending(current
)) {
5250 ret
= splice_to_pipe(pipe
, &spd
);
5251 splice_shrink_spd(&spd
);
5253 mutex_unlock(&trace_types_lock
);
5258 static const struct file_operations tracing_buffers_fops
= {
5259 .open
= tracing_buffers_open
,
5260 .read
= tracing_buffers_read
,
5261 .poll
= tracing_buffers_poll
,
5262 .release
= tracing_buffers_release
,
5263 .splice_read
= tracing_buffers_splice_read
,
5264 .llseek
= no_llseek
,
5268 tracing_stats_read(struct file
*filp
, char __user
*ubuf
,
5269 size_t count
, loff_t
*ppos
)
5271 struct trace_cpu
*tc
= filp
->private_data
;
5272 struct trace_array
*tr
= tc
->tr
;
5273 struct trace_buffer
*trace_buf
= &tr
->trace_buffer
;
5274 struct trace_seq
*s
;
5276 unsigned long long t
;
5277 unsigned long usec_rem
;
5280 s
= kmalloc(sizeof(*s
), GFP_KERNEL
);
5286 cnt
= ring_buffer_entries_cpu(trace_buf
->buffer
, cpu
);
5287 trace_seq_printf(s
, "entries: %ld\n", cnt
);
5289 cnt
= ring_buffer_overrun_cpu(trace_buf
->buffer
, cpu
);
5290 trace_seq_printf(s
, "overrun: %ld\n", cnt
);
5292 cnt
= ring_buffer_commit_overrun_cpu(trace_buf
->buffer
, cpu
);
5293 trace_seq_printf(s
, "commit overrun: %ld\n", cnt
);
5295 cnt
= ring_buffer_bytes_cpu(trace_buf
->buffer
, cpu
);
5296 trace_seq_printf(s
, "bytes: %ld\n", cnt
);
5298 if (trace_clocks
[tr
->clock_id
].in_ns
) {
5299 /* local or global for trace_clock */
5300 t
= ns2usecs(ring_buffer_oldest_event_ts(trace_buf
->buffer
, cpu
));
5301 usec_rem
= do_div(t
, USEC_PER_SEC
);
5302 trace_seq_printf(s
, "oldest event ts: %5llu.%06lu\n",
5305 t
= ns2usecs(ring_buffer_time_stamp(trace_buf
->buffer
, cpu
));
5306 usec_rem
= do_div(t
, USEC_PER_SEC
);
5307 trace_seq_printf(s
, "now ts: %5llu.%06lu\n", t
, usec_rem
);
5309 /* counter or tsc mode for trace_clock */
5310 trace_seq_printf(s
, "oldest event ts: %llu\n",
5311 ring_buffer_oldest_event_ts(trace_buf
->buffer
, cpu
));
5313 trace_seq_printf(s
, "now ts: %llu\n",
5314 ring_buffer_time_stamp(trace_buf
->buffer
, cpu
));
5317 cnt
= ring_buffer_dropped_events_cpu(trace_buf
->buffer
, cpu
);
5318 trace_seq_printf(s
, "dropped events: %ld\n", cnt
);
5320 cnt
= ring_buffer_read_events_cpu(trace_buf
->buffer
, cpu
);
5321 trace_seq_printf(s
, "read events: %ld\n", cnt
);
5323 count
= simple_read_from_buffer(ubuf
, count
, ppos
, s
->buffer
, s
->len
);
5330 static const struct file_operations tracing_stats_fops
= {
5331 .open
= tracing_open_generic
,
5332 .read
= tracing_stats_read
,
5333 .llseek
= generic_file_llseek
,
5336 #ifdef CONFIG_DYNAMIC_FTRACE
5338 int __weak
ftrace_arch_read_dyn_info(char *buf
, int size
)
5344 tracing_read_dyn_info(struct file
*filp
, char __user
*ubuf
,
5345 size_t cnt
, loff_t
*ppos
)
5347 static char ftrace_dyn_info_buffer
[1024];
5348 static DEFINE_MUTEX(dyn_info_mutex
);
5349 unsigned long *p
= filp
->private_data
;
5350 char *buf
= ftrace_dyn_info_buffer
;
5351 int size
= ARRAY_SIZE(ftrace_dyn_info_buffer
);
5354 mutex_lock(&dyn_info_mutex
);
5355 r
= sprintf(buf
, "%ld ", *p
);
5357 r
+= ftrace_arch_read_dyn_info(buf
+r
, (size
-1)-r
);
5360 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
5362 mutex_unlock(&dyn_info_mutex
);
5367 static const struct file_operations tracing_dyn_info_fops
= {
5368 .open
= tracing_open_generic
,
5369 .read
= tracing_read_dyn_info
,
5370 .llseek
= generic_file_llseek
,
5372 #endif /* CONFIG_DYNAMIC_FTRACE */
5374 #if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
5376 ftrace_snapshot(unsigned long ip
, unsigned long parent_ip
, void **data
)
5382 ftrace_count_snapshot(unsigned long ip
, unsigned long parent_ip
, void **data
)
5384 unsigned long *count
= (long *)data
;
5396 ftrace_snapshot_print(struct seq_file
*m
, unsigned long ip
,
5397 struct ftrace_probe_ops
*ops
, void *data
)
5399 long count
= (long)data
;
5401 seq_printf(m
, "%ps:", (void *)ip
);
5403 seq_printf(m
, "snapshot");
5406 seq_printf(m
, ":unlimited\n");
5408 seq_printf(m
, ":count=%ld\n", count
);
5413 static struct ftrace_probe_ops snapshot_probe_ops
= {
5414 .func
= ftrace_snapshot
,
5415 .print
= ftrace_snapshot_print
,
5418 static struct ftrace_probe_ops snapshot_count_probe_ops
= {
5419 .func
= ftrace_count_snapshot
,
5420 .print
= ftrace_snapshot_print
,
5424 ftrace_trace_snapshot_callback(struct ftrace_hash
*hash
,
5425 char *glob
, char *cmd
, char *param
, int enable
)
5427 struct ftrace_probe_ops
*ops
;
5428 void *count
= (void *)-1;
5432 /* hash funcs only work with set_ftrace_filter */
5436 ops
= param
? &snapshot_count_probe_ops
: &snapshot_probe_ops
;
5438 if (glob
[0] == '!') {
5439 unregister_ftrace_function_probe_func(glob
+1, ops
);
5446 number
= strsep(¶m
, ":");
5448 if (!strlen(number
))
5452 * We use the callback data field (which is a pointer)
5455 ret
= kstrtoul(number
, 0, (unsigned long *)&count
);
5460 ret
= register_ftrace_function_probe(glob
, ops
, count
);
5463 alloc_snapshot(&global_trace
);
5465 return ret
< 0 ? ret
: 0;
5468 static struct ftrace_func_command ftrace_snapshot_cmd
= {
5470 .func
= ftrace_trace_snapshot_callback
,
5473 static int register_snapshot_cmd(void)
5475 return register_ftrace_command(&ftrace_snapshot_cmd
);
5478 static inline int register_snapshot_cmd(void) { return 0; }
5479 #endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
5481 struct dentry
*tracing_init_dentry_tr(struct trace_array
*tr
)
5486 if (!debugfs_initialized())
5489 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
5490 tr
->dir
= debugfs_create_dir("tracing", NULL
);
5493 pr_warn_once("Could not create debugfs directory 'tracing'\n");
5498 struct dentry
*tracing_init_dentry(void)
5500 return tracing_init_dentry_tr(&global_trace
);
5503 static struct dentry
*tracing_dentry_percpu(struct trace_array
*tr
, int cpu
)
5505 struct dentry
*d_tracer
;
5508 return tr
->percpu_dir
;
5510 d_tracer
= tracing_init_dentry_tr(tr
);
5514 tr
->percpu_dir
= debugfs_create_dir("per_cpu", d_tracer
);
5516 WARN_ONCE(!tr
->percpu_dir
,
5517 "Could not create debugfs directory 'per_cpu/%d'\n", cpu
);
5519 return tr
->percpu_dir
;
5523 tracing_init_debugfs_percpu(struct trace_array
*tr
, long cpu
)
5525 struct trace_array_cpu
*data
= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
);
5526 struct dentry
*d_percpu
= tracing_dentry_percpu(tr
, cpu
);
5527 struct dentry
*d_cpu
;
5528 char cpu_dir
[30]; /* 30 characters should be more than enough */
5533 snprintf(cpu_dir
, 30, "cpu%ld", cpu
);
5534 d_cpu
= debugfs_create_dir(cpu_dir
, d_percpu
);
5536 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir
);
5540 /* per cpu trace_pipe */
5541 trace_create_file("trace_pipe", 0444, d_cpu
,
5542 (void *)&data
->trace_cpu
, &tracing_pipe_fops
);
5545 trace_create_file("trace", 0644, d_cpu
,
5546 (void *)&data
->trace_cpu
, &tracing_fops
);
5548 trace_create_file("trace_pipe_raw", 0444, d_cpu
,
5549 (void *)&data
->trace_cpu
, &tracing_buffers_fops
);
5551 trace_create_file("stats", 0444, d_cpu
,
5552 (void *)&data
->trace_cpu
, &tracing_stats_fops
);
5554 trace_create_file("buffer_size_kb", 0444, d_cpu
,
5555 (void *)&data
->trace_cpu
, &tracing_entries_fops
);
5557 #ifdef CONFIG_TRACER_SNAPSHOT
5558 trace_create_file("snapshot", 0644, d_cpu
,
5559 (void *)&data
->trace_cpu
, &snapshot_fops
);
5561 trace_create_file("snapshot_raw", 0444, d_cpu
,
5562 (void *)&data
->trace_cpu
, &snapshot_raw_fops
);
5566 #ifdef CONFIG_FTRACE_SELFTEST
5567 /* Let selftest have access to static functions in this file */
5568 #include "trace_selftest.c"
5571 struct trace_option_dentry
{
5572 struct tracer_opt
*opt
;
5573 struct tracer_flags
*flags
;
5574 struct trace_array
*tr
;
5575 struct dentry
*entry
;
5579 trace_options_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
5582 struct trace_option_dentry
*topt
= filp
->private_data
;
5585 if (topt
->flags
->val
& topt
->opt
->bit
)
5590 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
5594 trace_options_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
5597 struct trace_option_dentry
*topt
= filp
->private_data
;
5601 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5605 if (val
!= 0 && val
!= 1)
5608 if (!!(topt
->flags
->val
& topt
->opt
->bit
) != val
) {
5609 mutex_lock(&trace_types_lock
);
5610 ret
= __set_tracer_option(topt
->tr
->current_trace
, topt
->flags
,
5612 mutex_unlock(&trace_types_lock
);
5623 static const struct file_operations trace_options_fops
= {
5624 .open
= tracing_open_generic
,
5625 .read
= trace_options_read
,
5626 .write
= trace_options_write
,
5627 .llseek
= generic_file_llseek
,
5631 trace_options_core_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
5634 long index
= (long)filp
->private_data
;
5637 if (trace_flags
& (1 << index
))
5642 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
5646 trace_options_core_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
5649 struct trace_array
*tr
= &global_trace
;
5650 long index
= (long)filp
->private_data
;
5654 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5658 if (val
!= 0 && val
!= 1)
5661 mutex_lock(&trace_types_lock
);
5662 ret
= set_tracer_flag(tr
, 1 << index
, val
);
5663 mutex_unlock(&trace_types_lock
);
5673 static const struct file_operations trace_options_core_fops
= {
5674 .open
= tracing_open_generic
,
5675 .read
= trace_options_core_read
,
5676 .write
= trace_options_core_write
,
5677 .llseek
= generic_file_llseek
,
5680 struct dentry
*trace_create_file(const char *name
,
5682 struct dentry
*parent
,
5684 const struct file_operations
*fops
)
5688 ret
= debugfs_create_file(name
, mode
, parent
, data
, fops
);
5690 pr_warning("Could not create debugfs '%s' entry\n", name
);
5696 static struct dentry
*trace_options_init_dentry(struct trace_array
*tr
)
5698 struct dentry
*d_tracer
;
5703 d_tracer
= tracing_init_dentry_tr(tr
);
5707 tr
->options
= debugfs_create_dir("options", d_tracer
);
5709 pr_warning("Could not create debugfs directory 'options'\n");
5717 create_trace_option_file(struct trace_array
*tr
,
5718 struct trace_option_dentry
*topt
,
5719 struct tracer_flags
*flags
,
5720 struct tracer_opt
*opt
)
5722 struct dentry
*t_options
;
5724 t_options
= trace_options_init_dentry(tr
);
5728 topt
->flags
= flags
;
5732 topt
->entry
= trace_create_file(opt
->name
, 0644, t_options
, topt
,
5733 &trace_options_fops
);
5737 static struct trace_option_dentry
*
5738 create_trace_option_files(struct trace_array
*tr
, struct tracer
*tracer
)
5740 struct trace_option_dentry
*topts
;
5741 struct tracer_flags
*flags
;
5742 struct tracer_opt
*opts
;
5748 flags
= tracer
->flags
;
5750 if (!flags
|| !flags
->opts
)
5755 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
5758 topts
= kcalloc(cnt
+ 1, sizeof(*topts
), GFP_KERNEL
);
5762 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
5763 create_trace_option_file(tr
, &topts
[cnt
], flags
,
5770 destroy_trace_option_files(struct trace_option_dentry
*topts
)
5777 for (cnt
= 0; topts
[cnt
].opt
; cnt
++) {
5778 if (topts
[cnt
].entry
)
5779 debugfs_remove(topts
[cnt
].entry
);
5785 static struct dentry
*
5786 create_trace_option_core_file(struct trace_array
*tr
,
5787 const char *option
, long index
)
5789 struct dentry
*t_options
;
5791 t_options
= trace_options_init_dentry(tr
);
5795 return trace_create_file(option
, 0644, t_options
, (void *)index
,
5796 &trace_options_core_fops
);
5799 static __init
void create_trace_options_dir(struct trace_array
*tr
)
5801 struct dentry
*t_options
;
5804 t_options
= trace_options_init_dentry(tr
);
5808 for (i
= 0; trace_options
[i
]; i
++)
5809 create_trace_option_core_file(tr
, trace_options
[i
], i
);
5813 rb_simple_read(struct file
*filp
, char __user
*ubuf
,
5814 size_t cnt
, loff_t
*ppos
)
5816 struct trace_array
*tr
= filp
->private_data
;
5820 r
= tracer_tracing_is_on(tr
);
5821 r
= sprintf(buf
, "%d\n", r
);
5823 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
5827 rb_simple_write(struct file
*filp
, const char __user
*ubuf
,
5828 size_t cnt
, loff_t
*ppos
)
5830 struct trace_array
*tr
= filp
->private_data
;
5831 struct ring_buffer
*buffer
= tr
->trace_buffer
.buffer
;
5835 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5840 mutex_lock(&trace_types_lock
);
5842 tracer_tracing_on(tr
);
5843 if (tr
->current_trace
->start
)
5844 tr
->current_trace
->start(tr
);
5846 tracer_tracing_off(tr
);
5847 if (tr
->current_trace
->stop
)
5848 tr
->current_trace
->stop(tr
);
5850 mutex_unlock(&trace_types_lock
);
5858 static const struct file_operations rb_simple_fops
= {
5859 .open
= tracing_open_generic_tr
,
5860 .read
= rb_simple_read
,
5861 .write
= rb_simple_write
,
5862 .release
= tracing_release_generic_tr
,
5863 .llseek
= default_llseek
,
5866 struct dentry
*trace_instance_dir
;
5869 init_tracer_debugfs(struct trace_array
*tr
, struct dentry
*d_tracer
);
5871 static void init_trace_buffers(struct trace_array
*tr
, struct trace_buffer
*buf
)
5875 for_each_tracing_cpu(cpu
) {
5876 memset(per_cpu_ptr(buf
->data
, cpu
), 0, sizeof(struct trace_array_cpu
));
5877 per_cpu_ptr(buf
->data
, cpu
)->trace_cpu
.cpu
= cpu
;
5878 per_cpu_ptr(buf
->data
, cpu
)->trace_cpu
.tr
= tr
;
5883 allocate_trace_buffer(struct trace_array
*tr
, struct trace_buffer
*buf
, int size
)
5885 enum ring_buffer_flags rb_flags
;
5887 rb_flags
= trace_flags
& TRACE_ITER_OVERWRITE
? RB_FL_OVERWRITE
: 0;
5889 buf
->buffer
= ring_buffer_alloc(size
, rb_flags
);
5893 buf
->data
= alloc_percpu(struct trace_array_cpu
);
5895 ring_buffer_free(buf
->buffer
);
5899 init_trace_buffers(tr
, buf
);
5901 /* Allocate the first page for all buffers */
5902 set_buffer_entries(&tr
->trace_buffer
,
5903 ring_buffer_size(tr
->trace_buffer
.buffer
, 0));
5908 static int allocate_trace_buffers(struct trace_array
*tr
, int size
)
5912 ret
= allocate_trace_buffer(tr
, &tr
->trace_buffer
, size
);
5916 #ifdef CONFIG_TRACER_MAX_TRACE
5917 ret
= allocate_trace_buffer(tr
, &tr
->max_buffer
,
5918 allocate_snapshot
? size
: 1);
5920 ring_buffer_free(tr
->trace_buffer
.buffer
);
5921 free_percpu(tr
->trace_buffer
.data
);
5924 tr
->allocated_snapshot
= allocate_snapshot
;
5927 * Only the top level trace array gets its snapshot allocated
5928 * from the kernel command line.
5930 allocate_snapshot
= false;
5935 static int new_instance_create(const char *name
)
5937 struct trace_array
*tr
;
5940 mutex_lock(&trace_types_lock
);
5943 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
5944 if (tr
->name
&& strcmp(tr
->name
, name
) == 0)
5949 tr
= kzalloc(sizeof(*tr
), GFP_KERNEL
);
5953 tr
->name
= kstrdup(name
, GFP_KERNEL
);
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 /* Holder for file callbacks */
5968 tr
->trace_cpu
.cpu
= RING_BUFFER_ALL_CPUS
;
5969 tr
->trace_cpu
.tr
= tr
;
5971 tr
->dir
= debugfs_create_dir(name
, trace_instance_dir
);
5975 ret
= event_trace_add_tracer(tr
->dir
, tr
);
5979 init_tracer_debugfs(tr
, tr
->dir
);
5981 list_add(&tr
->list
, &ftrace_trace_arrays
);
5983 mutex_unlock(&trace_types_lock
);
5988 if (tr
->trace_buffer
.buffer
)
5989 ring_buffer_free(tr
->trace_buffer
.buffer
);
5994 mutex_unlock(&trace_types_lock
);
6000 static int instance_delete(const char *name
)
6002 struct trace_array
*tr
;
6006 mutex_lock(&trace_types_lock
);
6009 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
6010 if (tr
->name
&& strcmp(tr
->name
, name
) == 0) {
6022 list_del(&tr
->list
);
6024 event_trace_del_tracer(tr
);
6025 debugfs_remove_recursive(tr
->dir
);
6026 free_percpu(tr
->trace_buffer
.data
);
6027 ring_buffer_free(tr
->trace_buffer
.buffer
);
6035 mutex_unlock(&trace_types_lock
);
6040 static int instance_mkdir (struct inode
*inode
, struct dentry
*dentry
, umode_t mode
)
6042 struct dentry
*parent
;
6045 /* Paranoid: Make sure the parent is the "instances" directory */
6046 parent
= hlist_entry(inode
->i_dentry
.first
, struct dentry
, d_alias
);
6047 if (WARN_ON_ONCE(parent
!= trace_instance_dir
))
6051 * The inode mutex is locked, but debugfs_create_dir() will also
6052 * take the mutex. As the instances directory can not be destroyed
6053 * or changed in any other way, it is safe to unlock it, and
6054 * let the dentry try. If two users try to make the same dir at
6055 * the same time, then the new_instance_create() will determine the
6058 mutex_unlock(&inode
->i_mutex
);
6060 ret
= new_instance_create(dentry
->d_iname
);
6062 mutex_lock(&inode
->i_mutex
);
6067 static int instance_rmdir(struct inode
*inode
, struct dentry
*dentry
)
6069 struct dentry
*parent
;
6072 /* Paranoid: Make sure the parent is the "instances" directory */
6073 parent
= hlist_entry(inode
->i_dentry
.first
, struct dentry
, d_alias
);
6074 if (WARN_ON_ONCE(parent
!= trace_instance_dir
))
6077 /* The caller did a dget() on dentry */
6078 mutex_unlock(&dentry
->d_inode
->i_mutex
);
6081 * The inode mutex is locked, but debugfs_create_dir() will also
6082 * take the mutex. As the instances directory can not be destroyed
6083 * or changed in any other way, it is safe to unlock it, and
6084 * let the dentry try. If two users try to make the same dir at
6085 * the same time, then the instance_delete() will determine the
6088 mutex_unlock(&inode
->i_mutex
);
6090 ret
= instance_delete(dentry
->d_iname
);
6092 mutex_lock_nested(&inode
->i_mutex
, I_MUTEX_PARENT
);
6093 mutex_lock(&dentry
->d_inode
->i_mutex
);
6098 static const struct inode_operations instance_dir_inode_operations
= {
6099 .lookup
= simple_lookup
,
6100 .mkdir
= instance_mkdir
,
6101 .rmdir
= instance_rmdir
,
6104 static __init
void create_trace_instances(struct dentry
*d_tracer
)
6106 trace_instance_dir
= debugfs_create_dir("instances", d_tracer
);
6107 if (WARN_ON(!trace_instance_dir
))
6110 /* Hijack the dir inode operations, to allow mkdir */
6111 trace_instance_dir
->d_inode
->i_op
= &instance_dir_inode_operations
;
6115 init_tracer_debugfs(struct trace_array
*tr
, struct dentry
*d_tracer
)
6119 trace_create_file("trace_options", 0644, d_tracer
,
6120 tr
, &tracing_iter_fops
);
6122 trace_create_file("trace", 0644, d_tracer
,
6123 (void *)&tr
->trace_cpu
, &tracing_fops
);
6125 trace_create_file("trace_pipe", 0444, d_tracer
,
6126 (void *)&tr
->trace_cpu
, &tracing_pipe_fops
);
6128 trace_create_file("buffer_size_kb", 0644, d_tracer
,
6129 (void *)&tr
->trace_cpu
, &tracing_entries_fops
);
6131 trace_create_file("buffer_total_size_kb", 0444, d_tracer
,
6132 tr
, &tracing_total_entries_fops
);
6134 trace_create_file("free_buffer", 0200, d_tracer
,
6135 tr
, &tracing_free_buffer_fops
);
6137 trace_create_file("trace_marker", 0220, d_tracer
,
6138 tr
, &tracing_mark_fops
);
6140 trace_create_file("trace_clock", 0644, d_tracer
, tr
,
6143 trace_create_file("tracing_on", 0644, d_tracer
,
6144 tr
, &rb_simple_fops
);
6146 #ifdef CONFIG_TRACER_SNAPSHOT
6147 trace_create_file("snapshot", 0644, d_tracer
,
6148 (void *)&tr
->trace_cpu
, &snapshot_fops
);
6151 for_each_tracing_cpu(cpu
)
6152 tracing_init_debugfs_percpu(tr
, cpu
);
6156 static __init
int tracer_init_debugfs(void)
6158 struct dentry
*d_tracer
;
6160 trace_access_lock_init();
6162 d_tracer
= tracing_init_dentry();
6166 init_tracer_debugfs(&global_trace
, d_tracer
);
6168 trace_create_file("tracing_cpumask", 0644, d_tracer
,
6169 &global_trace
, &tracing_cpumask_fops
);
6171 trace_create_file("available_tracers", 0444, d_tracer
,
6172 &global_trace
, &show_traces_fops
);
6174 trace_create_file("current_tracer", 0644, d_tracer
,
6175 &global_trace
, &set_tracer_fops
);
6177 #ifdef CONFIG_TRACER_MAX_TRACE
6178 trace_create_file("tracing_max_latency", 0644, d_tracer
,
6179 &tracing_max_latency
, &tracing_max_lat_fops
);
6182 trace_create_file("tracing_thresh", 0644, d_tracer
,
6183 &tracing_thresh
, &tracing_max_lat_fops
);
6185 trace_create_file("README", 0444, d_tracer
,
6186 NULL
, &tracing_readme_fops
);
6188 trace_create_file("saved_cmdlines", 0444, d_tracer
,
6189 NULL
, &tracing_saved_cmdlines_fops
);
6191 #ifdef CONFIG_DYNAMIC_FTRACE
6192 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
6193 &ftrace_update_tot_cnt
, &tracing_dyn_info_fops
);
6196 create_trace_instances(d_tracer
);
6198 create_trace_options_dir(&global_trace
);
6203 static int trace_panic_handler(struct notifier_block
*this,
6204 unsigned long event
, void *unused
)
6206 if (ftrace_dump_on_oops
)
6207 ftrace_dump(ftrace_dump_on_oops
);
6211 static struct notifier_block trace_panic_notifier
= {
6212 .notifier_call
= trace_panic_handler
,
6214 .priority
= 150 /* priority: INT_MAX >= x >= 0 */
6217 static int trace_die_handler(struct notifier_block
*self
,
6223 if (ftrace_dump_on_oops
)
6224 ftrace_dump(ftrace_dump_on_oops
);
6232 static struct notifier_block trace_die_notifier
= {
6233 .notifier_call
= trace_die_handler
,
6238 * printk is set to max of 1024, we really don't need it that big.
6239 * Nothing should be printing 1000 characters anyway.
6241 #define TRACE_MAX_PRINT 1000
6244 * Define here KERN_TRACE so that we have one place to modify
6245 * it if we decide to change what log level the ftrace dump
6248 #define KERN_TRACE KERN_EMERG
6251 trace_printk_seq(struct trace_seq
*s
)
6253 /* Probably should print a warning here. */
6254 if (s
->len
>= TRACE_MAX_PRINT
)
6255 s
->len
= TRACE_MAX_PRINT
;
6257 /* should be zero ended, but we are paranoid. */
6258 s
->buffer
[s
->len
] = 0;
6260 printk(KERN_TRACE
"%s", s
->buffer
);
6265 void trace_init_global_iter(struct trace_iterator
*iter
)
6267 iter
->tr
= &global_trace
;
6268 iter
->trace
= iter
->tr
->current_trace
;
6269 iter
->cpu_file
= RING_BUFFER_ALL_CPUS
;
6270 iter
->trace_buffer
= &global_trace
.trace_buffer
;
6273 void ftrace_dump(enum ftrace_dump_mode oops_dump_mode
)
6275 /* use static because iter can be a bit big for the stack */
6276 static struct trace_iterator iter
;
6277 static atomic_t dump_running
;
6278 unsigned int old_userobj
;
6279 unsigned long flags
;
6282 /* Only allow one dump user at a time. */
6283 if (atomic_inc_return(&dump_running
) != 1) {
6284 atomic_dec(&dump_running
);
6289 * Always turn off tracing when we dump.
6290 * We don't need to show trace output of what happens
6291 * between multiple crashes.
6293 * If the user does a sysrq-z, then they can re-enable
6294 * tracing with echo 1 > tracing_on.
6298 local_irq_save(flags
);
6300 /* Simulate the iterator */
6301 trace_init_global_iter(&iter
);
6303 for_each_tracing_cpu(cpu
) {
6304 atomic_inc(&per_cpu_ptr(iter
.tr
->trace_buffer
.data
, cpu
)->disabled
);
6307 old_userobj
= trace_flags
& TRACE_ITER_SYM_USEROBJ
;
6309 /* don't look at user memory in panic mode */
6310 trace_flags
&= ~TRACE_ITER_SYM_USEROBJ
;
6312 switch (oops_dump_mode
) {
6314 iter
.cpu_file
= RING_BUFFER_ALL_CPUS
;
6317 iter
.cpu_file
= raw_smp_processor_id();
6322 printk(KERN_TRACE
"Bad dumping mode, switching to all CPUs dump\n");
6323 iter
.cpu_file
= RING_BUFFER_ALL_CPUS
;
6326 printk(KERN_TRACE
"Dumping ftrace buffer:\n");
6328 /* Did function tracer already get disabled? */
6329 if (ftrace_is_dead()) {
6330 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
6331 printk("# MAY BE MISSING FUNCTION EVENTS\n");
6335 * We need to stop all tracing on all CPUS to read the
6336 * the next buffer. This is a bit expensive, but is
6337 * not done often. We fill all what we can read,
6338 * and then release the locks again.
6341 while (!trace_empty(&iter
)) {
6344 printk(KERN_TRACE
"---------------------------------\n");
6348 /* reset all but tr, trace, and overruns */
6349 memset(&iter
.seq
, 0,
6350 sizeof(struct trace_iterator
) -
6351 offsetof(struct trace_iterator
, seq
));
6352 iter
.iter_flags
|= TRACE_FILE_LAT_FMT
;
6355 if (trace_find_next_entry_inc(&iter
) != NULL
) {
6358 ret
= print_trace_line(&iter
);
6359 if (ret
!= TRACE_TYPE_NO_CONSUME
)
6360 trace_consume(&iter
);
6362 touch_nmi_watchdog();
6364 trace_printk_seq(&iter
.seq
);
6368 printk(KERN_TRACE
" (ftrace buffer empty)\n");
6370 printk(KERN_TRACE
"---------------------------------\n");
6373 trace_flags
|= old_userobj
;
6375 for_each_tracing_cpu(cpu
) {
6376 atomic_dec(&per_cpu_ptr(iter
.trace_buffer
->data
, cpu
)->disabled
);
6378 atomic_dec(&dump_running
);
6379 local_irq_restore(flags
);
6381 EXPORT_SYMBOL_GPL(ftrace_dump
);
6383 __init
static int tracer_alloc_buffers(void)
6389 if (!alloc_cpumask_var(&tracing_buffer_mask
, GFP_KERNEL
))
6392 if (!alloc_cpumask_var(&tracing_cpumask
, GFP_KERNEL
))
6393 goto out_free_buffer_mask
;
6395 /* Only allocate trace_printk buffers if a trace_printk exists */
6396 if (__stop___trace_bprintk_fmt
!= __start___trace_bprintk_fmt
)
6397 /* Must be called before global_trace.buffer is allocated */
6398 trace_printk_init_buffers();
6400 /* To save memory, keep the ring buffer size to its minimum */
6401 if (ring_buffer_expanded
)
6402 ring_buf_size
= trace_buf_size
;
6406 cpumask_copy(tracing_buffer_mask
, cpu_possible_mask
);
6407 cpumask_copy(tracing_cpumask
, cpu_all_mask
);
6409 raw_spin_lock_init(&global_trace
.start_lock
);
6411 /* TODO: make the number of buffers hot pluggable with CPUS */
6412 if (allocate_trace_buffers(&global_trace
, ring_buf_size
) < 0) {
6413 printk(KERN_ERR
"tracer: failed to allocate ring buffer!\n");
6415 goto out_free_cpumask
;
6418 if (global_trace
.buffer_disabled
)
6421 trace_init_cmdlines();
6424 * register_tracer() might reference current_trace, so it
6425 * needs to be set before we register anything. This is
6426 * just a bootstrap of current_trace anyway.
6428 global_trace
.current_trace
= &nop_trace
;
6430 register_tracer(&nop_trace
);
6432 /* All seems OK, enable tracing */
6433 tracing_disabled
= 0;
6435 atomic_notifier_chain_register(&panic_notifier_list
,
6436 &trace_panic_notifier
);
6438 register_die_notifier(&trace_die_notifier
);
6440 global_trace
.flags
= TRACE_ARRAY_FL_GLOBAL
;
6442 /* Holder for file callbacks */
6443 global_trace
.trace_cpu
.cpu
= RING_BUFFER_ALL_CPUS
;
6444 global_trace
.trace_cpu
.tr
= &global_trace
;
6446 INIT_LIST_HEAD(&global_trace
.systems
);
6447 INIT_LIST_HEAD(&global_trace
.events
);
6448 list_add(&global_trace
.list
, &ftrace_trace_arrays
);
6450 while (trace_boot_options
) {
6453 option
= strsep(&trace_boot_options
, ",");
6454 trace_set_options(&global_trace
, option
);
6457 register_snapshot_cmd();
6462 free_percpu(global_trace
.trace_buffer
.data
);
6463 #ifdef CONFIG_TRACER_MAX_TRACE
6464 free_percpu(global_trace
.max_buffer
.data
);
6466 free_cpumask_var(tracing_cpumask
);
6467 out_free_buffer_mask
:
6468 free_cpumask_var(tracing_buffer_mask
);
6473 __init
static int clear_boot_tracer(void)
6476 * The default tracer at boot buffer is an init section.
6477 * This function is called in lateinit. If we did not
6478 * find the boot tracer, then clear it out, to prevent
6479 * later registration from accessing the buffer that is
6480 * about to be freed.
6482 if (!default_bootup_tracer
)
6485 printk(KERN_INFO
"ftrace bootup tracer '%s' not registered.\n",
6486 default_bootup_tracer
);
6487 default_bootup_tracer
= NULL
;
6492 early_initcall(tracer_alloc_buffers
);
6493 fs_initcall(tracer_init_debugfs
);
6494 late_initcall(clear_boot_tracer
);