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
buffer_ftrace_now(struct trace_buffer
*buf
, int cpu
)
250 /* Early boot up does not have a buffer yet */
252 return trace_clock_local();
254 ts
= ring_buffer_time_stamp(buf
->buffer
, cpu
);
255 ring_buffer_normalize_time_stamp(buf
->buffer
, cpu
, &ts
);
260 cycle_t
ftrace_now(int cpu
)
262 return buffer_ftrace_now(&global_trace
.trace_buffer
, cpu
);
266 * tracing_is_enabled - Show if global_trace has been disabled
268 * Shows if the global trace has been enabled or not. It uses the
269 * mirror flag "buffer_disabled" to be used in fast paths such as for
270 * the irqsoff tracer. But it may be inaccurate due to races. If you
271 * need to know the accurate state, use tracing_is_on() which is a little
272 * slower, but accurate.
274 int tracing_is_enabled(void)
277 * For quick access (irqsoff uses this in fast path), just
278 * return the mirror variable of the state of the ring buffer.
279 * It's a little racy, but we don't really care.
282 return !global_trace
.buffer_disabled
;
286 * trace_buf_size is the size in bytes that is allocated
287 * for a buffer. Note, the number of bytes is always rounded
290 * This number is purposely set to a low number of 16384.
291 * If the dump on oops happens, it will be much appreciated
292 * to not have to wait for all that output. Anyway this can be
293 * boot time and run time configurable.
295 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
297 static unsigned long trace_buf_size
= TRACE_BUF_SIZE_DEFAULT
;
299 /* trace_types holds a link list of available tracers. */
300 static struct tracer
*trace_types __read_mostly
;
303 * trace_types_lock is used to protect the trace_types list.
305 DEFINE_MUTEX(trace_types_lock
);
308 * serialize the access of the ring buffer
310 * ring buffer serializes readers, but it is low level protection.
311 * The validity of the events (which returns by ring_buffer_peek() ..etc)
312 * are not protected by ring buffer.
314 * The content of events may become garbage if we allow other process consumes
315 * these events concurrently:
316 * A) the page of the consumed events may become a normal page
317 * (not reader page) in ring buffer, and this page will be rewrited
318 * by events producer.
319 * B) The page of the consumed events may become a page for splice_read,
320 * and this page will be returned to system.
322 * These primitives allow multi process access to different cpu ring buffer
325 * These primitives don't distinguish read-only and read-consume access.
326 * Multi read-only access are also serialized.
330 static DECLARE_RWSEM(all_cpu_access_lock
);
331 static DEFINE_PER_CPU(struct mutex
, cpu_access_lock
);
333 static inline void trace_access_lock(int cpu
)
335 if (cpu
== RING_BUFFER_ALL_CPUS
) {
336 /* gain it for accessing the whole ring buffer. */
337 down_write(&all_cpu_access_lock
);
339 /* gain it for accessing a cpu ring buffer. */
341 /* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
342 down_read(&all_cpu_access_lock
);
344 /* Secondly block other access to this @cpu ring buffer. */
345 mutex_lock(&per_cpu(cpu_access_lock
, cpu
));
349 static inline void trace_access_unlock(int cpu
)
351 if (cpu
== RING_BUFFER_ALL_CPUS
) {
352 up_write(&all_cpu_access_lock
);
354 mutex_unlock(&per_cpu(cpu_access_lock
, cpu
));
355 up_read(&all_cpu_access_lock
);
359 static inline void trace_access_lock_init(void)
363 for_each_possible_cpu(cpu
)
364 mutex_init(&per_cpu(cpu_access_lock
, cpu
));
369 static DEFINE_MUTEX(access_lock
);
371 static inline void trace_access_lock(int cpu
)
374 mutex_lock(&access_lock
);
377 static inline void trace_access_unlock(int cpu
)
380 mutex_unlock(&access_lock
);
383 static inline void trace_access_lock_init(void)
389 /* trace_flags holds trace_options default values */
390 unsigned long trace_flags
= TRACE_ITER_PRINT_PARENT
| TRACE_ITER_PRINTK
|
391 TRACE_ITER_ANNOTATE
| TRACE_ITER_CONTEXT_INFO
| TRACE_ITER_SLEEP_TIME
|
392 TRACE_ITER_GRAPH_TIME
| TRACE_ITER_RECORD_CMD
| TRACE_ITER_OVERWRITE
|
393 TRACE_ITER_IRQ_INFO
| TRACE_ITER_MARKERS
| TRACE_ITER_FUNCTION
;
395 static void tracer_tracing_on(struct trace_array
*tr
)
397 if (tr
->trace_buffer
.buffer
)
398 ring_buffer_record_on(tr
->trace_buffer
.buffer
);
400 * This flag is looked at when buffers haven't been allocated
401 * yet, or by some tracers (like irqsoff), that just want to
402 * know if the ring buffer has been disabled, but it can handle
403 * races of where it gets disabled but we still do a record.
404 * As the check is in the fast path of the tracers, it is more
405 * important to be fast than accurate.
407 tr
->buffer_disabled
= 0;
408 /* Make the flag seen by readers */
413 * tracing_on - enable tracing buffers
415 * This function enables tracing buffers that may have been
416 * disabled with tracing_off.
418 void tracing_on(void)
420 tracer_tracing_on(&global_trace
);
422 EXPORT_SYMBOL_GPL(tracing_on
);
425 * __trace_puts - write a constant string into the trace buffer.
426 * @ip: The address of the caller
427 * @str: The constant string to write
428 * @size: The size of the string.
430 int __trace_puts(unsigned long ip
, const char *str
, int size
)
432 struct ring_buffer_event
*event
;
433 struct ring_buffer
*buffer
;
434 struct print_entry
*entry
;
435 unsigned long irq_flags
;
438 alloc
= sizeof(*entry
) + size
+ 2; /* possible \n added */
440 local_save_flags(irq_flags
);
441 buffer
= global_trace
.trace_buffer
.buffer
;
442 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, alloc
,
443 irq_flags
, preempt_count());
447 entry
= ring_buffer_event_data(event
);
450 memcpy(&entry
->buf
, str
, size
);
452 /* Add a newline if necessary */
453 if (entry
->buf
[size
- 1] != '\n') {
454 entry
->buf
[size
] = '\n';
455 entry
->buf
[size
+ 1] = '\0';
457 entry
->buf
[size
] = '\0';
459 __buffer_unlock_commit(buffer
, event
);
463 EXPORT_SYMBOL_GPL(__trace_puts
);
466 * __trace_bputs - write the pointer to a constant string into trace buffer
467 * @ip: The address of the caller
468 * @str: The constant string to write to the buffer to
470 int __trace_bputs(unsigned long ip
, const char *str
)
472 struct ring_buffer_event
*event
;
473 struct ring_buffer
*buffer
;
474 struct bputs_entry
*entry
;
475 unsigned long irq_flags
;
476 int size
= sizeof(struct bputs_entry
);
478 local_save_flags(irq_flags
);
479 buffer
= global_trace
.trace_buffer
.buffer
;
480 event
= trace_buffer_lock_reserve(buffer
, TRACE_BPUTS
, size
,
481 irq_flags
, preempt_count());
485 entry
= ring_buffer_event_data(event
);
489 __buffer_unlock_commit(buffer
, event
);
493 EXPORT_SYMBOL_GPL(__trace_bputs
);
495 #ifdef CONFIG_TRACER_SNAPSHOT
497 * trace_snapshot - take a snapshot of the current buffer.
499 * This causes a swap between the snapshot buffer and the current live
500 * tracing buffer. You can use this to take snapshots of the live
501 * trace when some condition is triggered, but continue to trace.
503 * Note, make sure to allocate the snapshot with either
504 * a tracing_snapshot_alloc(), or by doing it manually
505 * with: echo 1 > /sys/kernel/debug/tracing/snapshot
507 * If the snapshot buffer is not allocated, it will stop tracing.
508 * Basically making a permanent snapshot.
510 void tracing_snapshot(void)
512 struct trace_array
*tr
= &global_trace
;
513 struct tracer
*tracer
= tr
->current_trace
;
517 internal_trace_puts("*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
518 internal_trace_puts("*** snapshot is being ignored ***\n");
522 if (!tr
->allocated_snapshot
) {
523 internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n");
524 internal_trace_puts("*** stopping trace here! ***\n");
529 /* Note, snapshot can not be used when the tracer uses it */
530 if (tracer
->use_max_tr
) {
531 internal_trace_puts("*** LATENCY TRACER ACTIVE ***\n");
532 internal_trace_puts("*** Can not use snapshot (sorry) ***\n");
536 local_irq_save(flags
);
537 update_max_tr(tr
, current
, smp_processor_id());
538 local_irq_restore(flags
);
540 EXPORT_SYMBOL_GPL(tracing_snapshot
);
542 static int resize_buffer_duplicate_size(struct trace_buffer
*trace_buf
,
543 struct trace_buffer
*size_buf
, int cpu_id
);
544 static void set_buffer_entries(struct trace_buffer
*buf
, unsigned long val
);
546 static int alloc_snapshot(struct trace_array
*tr
)
550 if (!tr
->allocated_snapshot
) {
552 /* allocate spare buffer */
553 ret
= resize_buffer_duplicate_size(&tr
->max_buffer
,
554 &tr
->trace_buffer
, RING_BUFFER_ALL_CPUS
);
558 tr
->allocated_snapshot
= true;
564 void free_snapshot(struct trace_array
*tr
)
567 * We don't free the ring buffer. instead, resize it because
568 * The max_tr ring buffer has some state (e.g. ring->clock) and
569 * we want preserve it.
571 ring_buffer_resize(tr
->max_buffer
.buffer
, 1, RING_BUFFER_ALL_CPUS
);
572 set_buffer_entries(&tr
->max_buffer
, 1);
573 tracing_reset_online_cpus(&tr
->max_buffer
);
574 tr
->allocated_snapshot
= false;
578 * trace_snapshot_alloc - allocate and take a snapshot of the current buffer.
580 * This is similar to trace_snapshot(), but it will allocate the
581 * snapshot buffer if it isn't already allocated. Use this only
582 * where it is safe to sleep, as the allocation may sleep.
584 * This causes a swap between the snapshot buffer and the current live
585 * tracing buffer. You can use this to take snapshots of the live
586 * trace when some condition is triggered, but continue to trace.
588 void tracing_snapshot_alloc(void)
590 struct trace_array
*tr
= &global_trace
;
593 ret
= alloc_snapshot(tr
);
594 if (WARN_ON(ret
< 0))
599 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc
);
601 void tracing_snapshot(void)
603 WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
605 EXPORT_SYMBOL_GPL(tracing_snapshot
);
606 void tracing_snapshot_alloc(void)
611 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc
);
612 #endif /* CONFIG_TRACER_SNAPSHOT */
614 static void tracer_tracing_off(struct trace_array
*tr
)
616 if (tr
->trace_buffer
.buffer
)
617 ring_buffer_record_off(tr
->trace_buffer
.buffer
);
619 * This flag is looked at when buffers haven't been allocated
620 * yet, or by some tracers (like irqsoff), that just want to
621 * know if the ring buffer has been disabled, but it can handle
622 * races of where it gets disabled but we still do a record.
623 * As the check is in the fast path of the tracers, it is more
624 * important to be fast than accurate.
626 tr
->buffer_disabled
= 1;
627 /* Make the flag seen by readers */
632 * tracing_off - turn off tracing buffers
634 * This function stops the tracing buffers from recording data.
635 * It does not disable any overhead the tracers themselves may
636 * be causing. This function simply causes all recording to
637 * the ring buffers to fail.
639 void tracing_off(void)
641 tracer_tracing_off(&global_trace
);
643 EXPORT_SYMBOL_GPL(tracing_off
);
645 void disable_trace_on_warning(void)
647 if (__disable_trace_on_warning
)
652 * tracer_tracing_is_on - show real state of ring buffer enabled
653 * @tr : the trace array to know if ring buffer is enabled
655 * Shows real state of the ring buffer if it is enabled or not.
657 static int tracer_tracing_is_on(struct trace_array
*tr
)
659 if (tr
->trace_buffer
.buffer
)
660 return ring_buffer_record_is_on(tr
->trace_buffer
.buffer
);
661 return !tr
->buffer_disabled
;
665 * tracing_is_on - show state of ring buffers enabled
667 int tracing_is_on(void)
669 return tracer_tracing_is_on(&global_trace
);
671 EXPORT_SYMBOL_GPL(tracing_is_on
);
673 static int __init
set_buf_size(char *str
)
675 unsigned long buf_size
;
679 buf_size
= memparse(str
, &str
);
680 /* nr_entries can not be zero */
683 trace_buf_size
= buf_size
;
686 __setup("trace_buf_size=", set_buf_size
);
688 static int __init
set_tracing_thresh(char *str
)
690 unsigned long threshold
;
695 ret
= kstrtoul(str
, 0, &threshold
);
698 tracing_thresh
= threshold
* 1000;
701 __setup("tracing_thresh=", set_tracing_thresh
);
703 unsigned long nsecs_to_usecs(unsigned long nsecs
)
708 /* These must match the bit postions in trace_iterator_flags */
709 static const char *trace_options
[] = {
742 int in_ns
; /* is this clock in nanoseconds? */
744 { trace_clock_local
, "local", 1 },
745 { trace_clock_global
, "global", 1 },
746 { trace_clock_counter
, "counter", 0 },
747 { trace_clock_jiffies
, "uptime", 1 },
748 { trace_clock
, "perf", 1 },
753 * trace_parser_get_init - gets the buffer for trace parser
755 int trace_parser_get_init(struct trace_parser
*parser
, int size
)
757 memset(parser
, 0, sizeof(*parser
));
759 parser
->buffer
= kmalloc(size
, GFP_KERNEL
);
768 * trace_parser_put - frees the buffer for trace parser
770 void trace_parser_put(struct trace_parser
*parser
)
772 kfree(parser
->buffer
);
776 * trace_get_user - reads the user input string separated by space
777 * (matched by isspace(ch))
779 * For each string found the 'struct trace_parser' is updated,
780 * and the function returns.
782 * Returns number of bytes read.
784 * See kernel/trace/trace.h for 'struct trace_parser' details.
786 int trace_get_user(struct trace_parser
*parser
, const char __user
*ubuf
,
787 size_t cnt
, loff_t
*ppos
)
794 trace_parser_clear(parser
);
796 ret
= get_user(ch
, ubuf
++);
804 * The parser is not finished with the last write,
805 * continue reading the user input without skipping spaces.
808 /* skip white space */
809 while (cnt
&& isspace(ch
)) {
810 ret
= get_user(ch
, ubuf
++);
817 /* only spaces were written */
827 /* read the non-space input */
828 while (cnt
&& !isspace(ch
)) {
829 if (parser
->idx
< parser
->size
- 1)
830 parser
->buffer
[parser
->idx
++] = ch
;
835 ret
= get_user(ch
, ubuf
++);
842 /* We either got finished input or we have to wait for another call. */
844 parser
->buffer
[parser
->idx
] = 0;
845 parser
->cont
= false;
848 parser
->buffer
[parser
->idx
++] = ch
;
858 ssize_t
trace_seq_to_user(struct trace_seq
*s
, char __user
*ubuf
, size_t cnt
)
866 if (s
->len
<= s
->readpos
)
869 len
= s
->len
- s
->readpos
;
872 ret
= copy_to_user(ubuf
, s
->buffer
+ s
->readpos
, cnt
);
882 static ssize_t
trace_seq_to_buffer(struct trace_seq
*s
, void *buf
, size_t cnt
)
886 if (s
->len
<= s
->readpos
)
889 len
= s
->len
- s
->readpos
;
892 memcpy(buf
, s
->buffer
+ s
->readpos
, cnt
);
899 * ftrace_max_lock is used to protect the swapping of buffers
900 * when taking a max snapshot. The buffers themselves are
901 * protected by per_cpu spinlocks. But the action of the swap
902 * needs its own lock.
904 * This is defined as a arch_spinlock_t in order to help
905 * with performance when lockdep debugging is enabled.
907 * It is also used in other places outside the update_max_tr
908 * so it needs to be defined outside of the
909 * CONFIG_TRACER_MAX_TRACE.
911 static arch_spinlock_t ftrace_max_lock
=
912 (arch_spinlock_t
)__ARCH_SPIN_LOCK_UNLOCKED
;
914 unsigned long __read_mostly tracing_thresh
;
916 #ifdef CONFIG_TRACER_MAX_TRACE
917 unsigned long __read_mostly tracing_max_latency
;
920 * Copy the new maximum trace into the separate maximum-trace
921 * structure. (this way the maximum trace is permanently saved,
922 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
925 __update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
927 struct trace_buffer
*trace_buf
= &tr
->trace_buffer
;
928 struct trace_buffer
*max_buf
= &tr
->max_buffer
;
929 struct trace_array_cpu
*data
= per_cpu_ptr(trace_buf
->data
, cpu
);
930 struct trace_array_cpu
*max_data
= per_cpu_ptr(max_buf
->data
, cpu
);
933 max_buf
->time_start
= data
->preempt_timestamp
;
935 max_data
->saved_latency
= tracing_max_latency
;
936 max_data
->critical_start
= data
->critical_start
;
937 max_data
->critical_end
= data
->critical_end
;
939 memcpy(max_data
->comm
, tsk
->comm
, TASK_COMM_LEN
);
940 max_data
->pid
= tsk
->pid
;
942 * If tsk == current, then use current_uid(), as that does not use
943 * RCU. The irq tracer can be called out of RCU scope.
946 max_data
->uid
= current_uid();
948 max_data
->uid
= task_uid(tsk
);
950 max_data
->nice
= tsk
->static_prio
- 20 - MAX_RT_PRIO
;
951 max_data
->policy
= tsk
->policy
;
952 max_data
->rt_priority
= tsk
->rt_priority
;
954 /* record this tasks comm */
955 tracing_record_cmdline(tsk
);
959 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
961 * @tsk: the task with the latency
962 * @cpu: The cpu that initiated the trace.
964 * Flip the buffers between the @tr and the max_tr and record information
965 * about which task was the cause of this latency.
968 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
970 struct ring_buffer
*buf
;
975 WARN_ON_ONCE(!irqs_disabled());
977 if (!tr
->allocated_snapshot
) {
978 /* Only the nop tracer should hit this when disabling */
979 WARN_ON_ONCE(tr
->current_trace
!= &nop_trace
);
983 arch_spin_lock(&ftrace_max_lock
);
985 buf
= tr
->trace_buffer
.buffer
;
986 tr
->trace_buffer
.buffer
= tr
->max_buffer
.buffer
;
987 tr
->max_buffer
.buffer
= buf
;
989 __update_max_tr(tr
, tsk
, cpu
);
990 arch_spin_unlock(&ftrace_max_lock
);
994 * update_max_tr_single - only copy one trace over, and reset the rest
996 * @tsk - task with the latency
997 * @cpu - the cpu of the buffer to copy.
999 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
1002 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
1009 WARN_ON_ONCE(!irqs_disabled());
1010 if (!tr
->allocated_snapshot
) {
1011 /* Only the nop tracer should hit this when disabling */
1012 WARN_ON_ONCE(tr
->current_trace
!= &nop_trace
);
1016 arch_spin_lock(&ftrace_max_lock
);
1018 ret
= ring_buffer_swap_cpu(tr
->max_buffer
.buffer
, tr
->trace_buffer
.buffer
, cpu
);
1020 if (ret
== -EBUSY
) {
1022 * We failed to swap the buffer due to a commit taking
1023 * place on this CPU. We fail to record, but we reset
1024 * the max trace buffer (no one writes directly to it)
1025 * and flag that it failed.
1027 trace_array_printk_buf(tr
->max_buffer
.buffer
, _THIS_IP_
,
1028 "Failed to swap buffers due to commit in progress\n");
1031 WARN_ON_ONCE(ret
&& ret
!= -EAGAIN
&& ret
!= -EBUSY
);
1033 __update_max_tr(tr
, tsk
, cpu
);
1034 arch_spin_unlock(&ftrace_max_lock
);
1036 #endif /* CONFIG_TRACER_MAX_TRACE */
1038 static void default_wait_pipe(struct trace_iterator
*iter
)
1040 /* Iterators are static, they should be filled or empty */
1041 if (trace_buffer_iter(iter
, iter
->cpu_file
))
1044 ring_buffer_wait(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
1047 #ifdef CONFIG_FTRACE_STARTUP_TEST
1048 static int run_tracer_selftest(struct tracer
*type
)
1050 struct trace_array
*tr
= &global_trace
;
1051 struct tracer
*saved_tracer
= tr
->current_trace
;
1054 if (!type
->selftest
|| tracing_selftest_disabled
)
1058 * Run a selftest on this tracer.
1059 * Here we reset the trace buffer, and set the current
1060 * tracer to be this tracer. The tracer can then run some
1061 * internal tracing to verify that everything is in order.
1062 * If we fail, we do not register this tracer.
1064 tracing_reset_online_cpus(&tr
->trace_buffer
);
1066 tr
->current_trace
= type
;
1068 #ifdef CONFIG_TRACER_MAX_TRACE
1069 if (type
->use_max_tr
) {
1070 /* If we expanded the buffers, make sure the max is expanded too */
1071 if (ring_buffer_expanded
)
1072 ring_buffer_resize(tr
->max_buffer
.buffer
, trace_buf_size
,
1073 RING_BUFFER_ALL_CPUS
);
1074 tr
->allocated_snapshot
= true;
1078 /* the test is responsible for initializing and enabling */
1079 pr_info("Testing tracer %s: ", type
->name
);
1080 ret
= type
->selftest(type
, tr
);
1081 /* the test is responsible for resetting too */
1082 tr
->current_trace
= saved_tracer
;
1084 printk(KERN_CONT
"FAILED!\n");
1085 /* Add the warning after printing 'FAILED' */
1089 /* Only reset on passing, to avoid touching corrupted buffers */
1090 tracing_reset_online_cpus(&tr
->trace_buffer
);
1092 #ifdef CONFIG_TRACER_MAX_TRACE
1093 if (type
->use_max_tr
) {
1094 tr
->allocated_snapshot
= false;
1096 /* Shrink the max buffer again */
1097 if (ring_buffer_expanded
)
1098 ring_buffer_resize(tr
->max_buffer
.buffer
, 1,
1099 RING_BUFFER_ALL_CPUS
);
1103 printk(KERN_CONT
"PASSED\n");
1107 static inline int run_tracer_selftest(struct tracer
*type
)
1111 #endif /* CONFIG_FTRACE_STARTUP_TEST */
1114 * register_tracer - register a tracer with the ftrace system.
1115 * @type - the plugin for the tracer
1117 * Register a new plugin tracer.
1119 int register_tracer(struct tracer
*type
)
1125 pr_info("Tracer must have a name\n");
1129 if (strlen(type
->name
) >= MAX_TRACER_SIZE
) {
1130 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE
);
1134 mutex_lock(&trace_types_lock
);
1136 tracing_selftest_running
= true;
1138 for (t
= trace_types
; t
; t
= t
->next
) {
1139 if (strcmp(type
->name
, t
->name
) == 0) {
1141 pr_info("Tracer %s already registered\n",
1148 if (!type
->set_flag
)
1149 type
->set_flag
= &dummy_set_flag
;
1151 type
->flags
= &dummy_tracer_flags
;
1153 if (!type
->flags
->opts
)
1154 type
->flags
->opts
= dummy_tracer_opt
;
1155 if (!type
->wait_pipe
)
1156 type
->wait_pipe
= default_wait_pipe
;
1158 ret
= run_tracer_selftest(type
);
1162 type
->next
= trace_types
;
1166 tracing_selftest_running
= false;
1167 mutex_unlock(&trace_types_lock
);
1169 if (ret
|| !default_bootup_tracer
)
1172 if (strncmp(default_bootup_tracer
, type
->name
, MAX_TRACER_SIZE
))
1175 printk(KERN_INFO
"Starting tracer '%s'\n", type
->name
);
1176 /* Do we want this tracer to start on bootup? */
1177 tracing_set_tracer(type
->name
);
1178 default_bootup_tracer
= NULL
;
1179 /* disable other selftests, since this will break it. */
1180 tracing_selftest_disabled
= true;
1181 #ifdef CONFIG_FTRACE_STARTUP_TEST
1182 printk(KERN_INFO
"Disabling FTRACE selftests due to running tracer '%s'\n",
1190 void tracing_reset(struct trace_buffer
*buf
, int cpu
)
1192 struct ring_buffer
*buffer
= buf
->buffer
;
1197 ring_buffer_record_disable(buffer
);
1199 /* Make sure all commits have finished */
1200 synchronize_sched();
1201 ring_buffer_reset_cpu(buffer
, cpu
);
1203 ring_buffer_record_enable(buffer
);
1206 void tracing_reset_online_cpus(struct trace_buffer
*buf
)
1208 struct ring_buffer
*buffer
= buf
->buffer
;
1214 ring_buffer_record_disable(buffer
);
1216 /* Make sure all commits have finished */
1217 synchronize_sched();
1219 buf
->time_start
= buffer_ftrace_now(buf
, buf
->cpu
);
1221 for_each_online_cpu(cpu
)
1222 ring_buffer_reset_cpu(buffer
, cpu
);
1224 ring_buffer_record_enable(buffer
);
1227 /* Must have trace_types_lock held */
1228 void tracing_reset_all_online_cpus(void)
1230 struct trace_array
*tr
;
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
);
1240 #define SAVED_CMDLINES 128
1241 #define NO_CMDLINE_MAP UINT_MAX
1242 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
1243 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
1244 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
1245 static int cmdline_idx
;
1246 static arch_spinlock_t trace_cmdline_lock
= __ARCH_SPIN_LOCK_UNLOCKED
;
1248 /* temporary disable recording */
1249 static atomic_t trace_record_cmdline_disabled __read_mostly
;
1251 static void trace_init_cmdlines(void)
1253 memset(&map_pid_to_cmdline
, NO_CMDLINE_MAP
, sizeof(map_pid_to_cmdline
));
1254 memset(&map_cmdline_to_pid
, NO_CMDLINE_MAP
, sizeof(map_cmdline_to_pid
));
1258 int is_tracing_stopped(void)
1260 return global_trace
.stop_count
;
1264 * ftrace_off_permanent - disable all ftrace code permanently
1266 * This should only be called when a serious anomally has
1267 * been detected. This will turn off the function tracing,
1268 * ring buffers, and other tracing utilites. It takes no
1269 * locks and can be called from any context.
1271 void ftrace_off_permanent(void)
1273 tracing_disabled
= 1;
1275 tracing_off_permanent();
1279 * tracing_start - quick start of the tracer
1281 * If tracing is enabled but was stopped by tracing_stop,
1282 * this will start the tracer back up.
1284 void tracing_start(void)
1286 struct ring_buffer
*buffer
;
1287 unsigned long flags
;
1289 if (tracing_disabled
)
1292 raw_spin_lock_irqsave(&global_trace
.start_lock
, flags
);
1293 if (--global_trace
.stop_count
) {
1294 if (global_trace
.stop_count
< 0) {
1295 /* Someone screwed up their debugging */
1297 global_trace
.stop_count
= 0;
1302 /* Prevent the buffers from switching */
1303 arch_spin_lock(&ftrace_max_lock
);
1305 buffer
= global_trace
.trace_buffer
.buffer
;
1307 ring_buffer_record_enable(buffer
);
1309 #ifdef CONFIG_TRACER_MAX_TRACE
1310 buffer
= global_trace
.max_buffer
.buffer
;
1312 ring_buffer_record_enable(buffer
);
1315 arch_spin_unlock(&ftrace_max_lock
);
1319 raw_spin_unlock_irqrestore(&global_trace
.start_lock
, flags
);
1322 static void tracing_start_tr(struct trace_array
*tr
)
1324 struct ring_buffer
*buffer
;
1325 unsigned long flags
;
1327 if (tracing_disabled
)
1330 /* If global, we need to also start the max tracer */
1331 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
1332 return tracing_start();
1334 raw_spin_lock_irqsave(&tr
->start_lock
, flags
);
1336 if (--tr
->stop_count
) {
1337 if (tr
->stop_count
< 0) {
1338 /* Someone screwed up their debugging */
1345 buffer
= tr
->trace_buffer
.buffer
;
1347 ring_buffer_record_enable(buffer
);
1350 raw_spin_unlock_irqrestore(&tr
->start_lock
, flags
);
1354 * tracing_stop - quick stop of the tracer
1356 * Light weight way to stop tracing. Use in conjunction with
1359 void tracing_stop(void)
1361 struct ring_buffer
*buffer
;
1362 unsigned long flags
;
1365 raw_spin_lock_irqsave(&global_trace
.start_lock
, flags
);
1366 if (global_trace
.stop_count
++)
1369 /* Prevent the buffers from switching */
1370 arch_spin_lock(&ftrace_max_lock
);
1372 buffer
= global_trace
.trace_buffer
.buffer
;
1374 ring_buffer_record_disable(buffer
);
1376 #ifdef CONFIG_TRACER_MAX_TRACE
1377 buffer
= global_trace
.max_buffer
.buffer
;
1379 ring_buffer_record_disable(buffer
);
1382 arch_spin_unlock(&ftrace_max_lock
);
1385 raw_spin_unlock_irqrestore(&global_trace
.start_lock
, flags
);
1388 static void tracing_stop_tr(struct trace_array
*tr
)
1390 struct ring_buffer
*buffer
;
1391 unsigned long flags
;
1393 /* If global, we need to also stop the max tracer */
1394 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
1395 return tracing_stop();
1397 raw_spin_lock_irqsave(&tr
->start_lock
, flags
);
1398 if (tr
->stop_count
++)
1401 buffer
= tr
->trace_buffer
.buffer
;
1403 ring_buffer_record_disable(buffer
);
1406 raw_spin_unlock_irqrestore(&tr
->start_lock
, flags
);
1409 void trace_stop_cmdline_recording(void);
1411 static void trace_save_cmdline(struct task_struct
*tsk
)
1415 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
1419 * It's not the end of the world if we don't get
1420 * the lock, but we also don't want to spin
1421 * nor do we want to disable interrupts,
1422 * so if we miss here, then better luck next time.
1424 if (!arch_spin_trylock(&trace_cmdline_lock
))
1427 idx
= map_pid_to_cmdline
[tsk
->pid
];
1428 if (idx
== NO_CMDLINE_MAP
) {
1429 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
1432 * Check whether the cmdline buffer at idx has a pid
1433 * mapped. We are going to overwrite that entry so we
1434 * need to clear the map_pid_to_cmdline. Otherwise we
1435 * would read the new comm for the old pid.
1437 pid
= map_cmdline_to_pid
[idx
];
1438 if (pid
!= NO_CMDLINE_MAP
)
1439 map_pid_to_cmdline
[pid
] = NO_CMDLINE_MAP
;
1441 map_cmdline_to_pid
[idx
] = tsk
->pid
;
1442 map_pid_to_cmdline
[tsk
->pid
] = idx
;
1447 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
1449 arch_spin_unlock(&trace_cmdline_lock
);
1452 void trace_find_cmdline(int pid
, char comm
[])
1457 strcpy(comm
, "<idle>");
1461 if (WARN_ON_ONCE(pid
< 0)) {
1462 strcpy(comm
, "<XXX>");
1466 if (pid
> PID_MAX_DEFAULT
) {
1467 strcpy(comm
, "<...>");
1472 arch_spin_lock(&trace_cmdline_lock
);
1473 map
= map_pid_to_cmdline
[pid
];
1474 if (map
!= NO_CMDLINE_MAP
)
1475 strcpy(comm
, saved_cmdlines
[map
]);
1477 strcpy(comm
, "<...>");
1479 arch_spin_unlock(&trace_cmdline_lock
);
1483 void tracing_record_cmdline(struct task_struct
*tsk
)
1485 if (atomic_read(&trace_record_cmdline_disabled
) || !tracing_is_on())
1488 if (!__this_cpu_read(trace_cmdline_save
))
1491 __this_cpu_write(trace_cmdline_save
, false);
1493 trace_save_cmdline(tsk
);
1497 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
,
1500 struct task_struct
*tsk
= current
;
1502 entry
->preempt_count
= pc
& 0xff;
1503 entry
->pid
= (tsk
) ? tsk
->pid
: 0;
1505 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1506 (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
1508 TRACE_FLAG_IRQS_NOSUPPORT
|
1510 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
1511 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
1512 (need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0);
1514 EXPORT_SYMBOL_GPL(tracing_generic_entry_update
);
1516 struct ring_buffer_event
*
1517 trace_buffer_lock_reserve(struct ring_buffer
*buffer
,
1520 unsigned long flags
, int pc
)
1522 struct ring_buffer_event
*event
;
1524 event
= ring_buffer_lock_reserve(buffer
, len
);
1525 if (event
!= NULL
) {
1526 struct trace_entry
*ent
= ring_buffer_event_data(event
);
1528 tracing_generic_entry_update(ent
, flags
, pc
);
1536 __buffer_unlock_commit(struct ring_buffer
*buffer
, struct ring_buffer_event
*event
)
1538 __this_cpu_write(trace_cmdline_save
, true);
1539 ring_buffer_unlock_commit(buffer
, event
);
1543 __trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1544 struct ring_buffer_event
*event
,
1545 unsigned long flags
, int pc
)
1547 __buffer_unlock_commit(buffer
, event
);
1549 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1550 ftrace_trace_userstack(buffer
, flags
, pc
);
1553 void trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1554 struct ring_buffer_event
*event
,
1555 unsigned long flags
, int pc
)
1557 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
);
1559 EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit
);
1561 struct ring_buffer_event
*
1562 trace_event_buffer_lock_reserve(struct ring_buffer
**current_rb
,
1563 struct ftrace_event_file
*ftrace_file
,
1564 int type
, unsigned long len
,
1565 unsigned long flags
, int pc
)
1567 *current_rb
= ftrace_file
->tr
->trace_buffer
.buffer
;
1568 return trace_buffer_lock_reserve(*current_rb
,
1569 type
, len
, flags
, pc
);
1571 EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve
);
1573 struct ring_buffer_event
*
1574 trace_current_buffer_lock_reserve(struct ring_buffer
**current_rb
,
1575 int type
, unsigned long len
,
1576 unsigned long flags
, int pc
)
1578 *current_rb
= global_trace
.trace_buffer
.buffer
;
1579 return trace_buffer_lock_reserve(*current_rb
,
1580 type
, len
, flags
, pc
);
1582 EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve
);
1584 void trace_current_buffer_unlock_commit(struct ring_buffer
*buffer
,
1585 struct ring_buffer_event
*event
,
1586 unsigned long flags
, int pc
)
1588 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
);
1590 EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit
);
1592 void trace_buffer_unlock_commit_regs(struct ring_buffer
*buffer
,
1593 struct ring_buffer_event
*event
,
1594 unsigned long flags
, int pc
,
1595 struct pt_regs
*regs
)
1597 __buffer_unlock_commit(buffer
, event
);
1599 ftrace_trace_stack_regs(buffer
, flags
, 0, pc
, regs
);
1600 ftrace_trace_userstack(buffer
, flags
, pc
);
1602 EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit_regs
);
1604 void trace_current_buffer_discard_commit(struct ring_buffer
*buffer
,
1605 struct ring_buffer_event
*event
)
1607 ring_buffer_discard_commit(buffer
, event
);
1609 EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit
);
1612 trace_function(struct trace_array
*tr
,
1613 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
1616 struct ftrace_event_call
*call
= &event_function
;
1617 struct ring_buffer
*buffer
= tr
->trace_buffer
.buffer
;
1618 struct ring_buffer_event
*event
;
1619 struct ftrace_entry
*entry
;
1621 /* If we are reading the ring buffer, don't trace */
1622 if (unlikely(__this_cpu_read(ftrace_cpu_disabled
)))
1625 event
= trace_buffer_lock_reserve(buffer
, TRACE_FN
, sizeof(*entry
),
1629 entry
= ring_buffer_event_data(event
);
1631 entry
->parent_ip
= parent_ip
;
1633 if (!filter_check_discard(call
, entry
, buffer
, event
))
1634 __buffer_unlock_commit(buffer
, event
);
1637 #ifdef CONFIG_STACKTRACE
1639 #define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
1640 struct ftrace_stack
{
1641 unsigned long calls
[FTRACE_STACK_MAX_ENTRIES
];
1644 static DEFINE_PER_CPU(struct ftrace_stack
, ftrace_stack
);
1645 static DEFINE_PER_CPU(int, ftrace_stack_reserve
);
1647 static void __ftrace_trace_stack(struct ring_buffer
*buffer
,
1648 unsigned long flags
,
1649 int skip
, int pc
, struct pt_regs
*regs
)
1651 struct ftrace_event_call
*call
= &event_kernel_stack
;
1652 struct ring_buffer_event
*event
;
1653 struct stack_entry
*entry
;
1654 struct stack_trace trace
;
1656 int size
= FTRACE_STACK_ENTRIES
;
1658 trace
.nr_entries
= 0;
1662 * Since events can happen in NMIs there's no safe way to
1663 * use the per cpu ftrace_stacks. We reserve it and if an interrupt
1664 * or NMI comes in, it will just have to use the default
1665 * FTRACE_STACK_SIZE.
1667 preempt_disable_notrace();
1669 use_stack
= __this_cpu_inc_return(ftrace_stack_reserve
);
1671 * We don't need any atomic variables, just a barrier.
1672 * If an interrupt comes in, we don't care, because it would
1673 * have exited and put the counter back to what we want.
1674 * We just need a barrier to keep gcc from moving things
1678 if (use_stack
== 1) {
1679 trace
.entries
= &__get_cpu_var(ftrace_stack
).calls
[0];
1680 trace
.max_entries
= FTRACE_STACK_MAX_ENTRIES
;
1683 save_stack_trace_regs(regs
, &trace
);
1685 save_stack_trace(&trace
);
1687 if (trace
.nr_entries
> size
)
1688 size
= trace
.nr_entries
;
1690 /* From now on, use_stack is a boolean */
1693 size
*= sizeof(unsigned long);
1695 event
= trace_buffer_lock_reserve(buffer
, TRACE_STACK
,
1696 sizeof(*entry
) + size
, flags
, pc
);
1699 entry
= ring_buffer_event_data(event
);
1701 memset(&entry
->caller
, 0, size
);
1704 memcpy(&entry
->caller
, trace
.entries
,
1705 trace
.nr_entries
* sizeof(unsigned long));
1707 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1708 trace
.entries
= entry
->caller
;
1710 save_stack_trace_regs(regs
, &trace
);
1712 save_stack_trace(&trace
);
1715 entry
->size
= trace
.nr_entries
;
1717 if (!filter_check_discard(call
, entry
, buffer
, event
))
1718 __buffer_unlock_commit(buffer
, event
);
1721 /* Again, don't let gcc optimize things here */
1723 __this_cpu_dec(ftrace_stack_reserve
);
1724 preempt_enable_notrace();
1728 void ftrace_trace_stack_regs(struct ring_buffer
*buffer
, unsigned long flags
,
1729 int skip
, int pc
, struct pt_regs
*regs
)
1731 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1734 __ftrace_trace_stack(buffer
, flags
, skip
, pc
, regs
);
1737 void ftrace_trace_stack(struct ring_buffer
*buffer
, unsigned long flags
,
1740 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1743 __ftrace_trace_stack(buffer
, flags
, skip
, pc
, NULL
);
1746 void __trace_stack(struct trace_array
*tr
, unsigned long flags
, int skip
,
1749 __ftrace_trace_stack(tr
->trace_buffer
.buffer
, flags
, skip
, pc
, NULL
);
1753 * trace_dump_stack - record a stack back trace in the trace buffer
1754 * @skip: Number of functions to skip (helper handlers)
1756 void trace_dump_stack(int skip
)
1758 unsigned long flags
;
1760 if (tracing_disabled
|| tracing_selftest_running
)
1763 local_save_flags(flags
);
1766 * Skip 3 more, seems to get us at the caller of
1770 __ftrace_trace_stack(global_trace
.trace_buffer
.buffer
,
1771 flags
, skip
, preempt_count(), NULL
);
1774 static DEFINE_PER_CPU(int, user_stack_count
);
1777 ftrace_trace_userstack(struct ring_buffer
*buffer
, unsigned long flags
, int pc
)
1779 struct ftrace_event_call
*call
= &event_user_stack
;
1780 struct ring_buffer_event
*event
;
1781 struct userstack_entry
*entry
;
1782 struct stack_trace trace
;
1784 if (!(trace_flags
& TRACE_ITER_USERSTACKTRACE
))
1788 * NMIs can not handle page faults, even with fix ups.
1789 * The save user stack can (and often does) fault.
1791 if (unlikely(in_nmi()))
1795 * prevent recursion, since the user stack tracing may
1796 * trigger other kernel events.
1799 if (__this_cpu_read(user_stack_count
))
1802 __this_cpu_inc(user_stack_count
);
1804 event
= trace_buffer_lock_reserve(buffer
, TRACE_USER_STACK
,
1805 sizeof(*entry
), flags
, pc
);
1807 goto out_drop_count
;
1808 entry
= ring_buffer_event_data(event
);
1810 entry
->tgid
= current
->tgid
;
1811 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
1813 trace
.nr_entries
= 0;
1814 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1816 trace
.entries
= entry
->caller
;
1818 save_stack_trace_user(&trace
);
1819 if (!filter_check_discard(call
, entry
, buffer
, event
))
1820 __buffer_unlock_commit(buffer
, event
);
1823 __this_cpu_dec(user_stack_count
);
1829 static void __trace_userstack(struct trace_array
*tr
, unsigned long flags
)
1831 ftrace_trace_userstack(tr
, flags
, preempt_count());
1835 #endif /* CONFIG_STACKTRACE */
1837 /* created for use with alloc_percpu */
1838 struct trace_buffer_struct
{
1839 char buffer
[TRACE_BUF_SIZE
];
1842 static struct trace_buffer_struct
*trace_percpu_buffer
;
1843 static struct trace_buffer_struct
*trace_percpu_sirq_buffer
;
1844 static struct trace_buffer_struct
*trace_percpu_irq_buffer
;
1845 static struct trace_buffer_struct
*trace_percpu_nmi_buffer
;
1848 * The buffer used is dependent on the context. There is a per cpu
1849 * buffer for normal context, softirq contex, hard irq context and
1850 * for NMI context. Thise allows for lockless recording.
1852 * Note, if the buffers failed to be allocated, then this returns NULL
1854 static char *get_trace_buf(void)
1856 struct trace_buffer_struct
*percpu_buffer
;
1859 * If we have allocated per cpu buffers, then we do not
1860 * need to do any locking.
1863 percpu_buffer
= trace_percpu_nmi_buffer
;
1865 percpu_buffer
= trace_percpu_irq_buffer
;
1866 else if (in_softirq())
1867 percpu_buffer
= trace_percpu_sirq_buffer
;
1869 percpu_buffer
= trace_percpu_buffer
;
1874 return this_cpu_ptr(&percpu_buffer
->buffer
[0]);
1877 static int alloc_percpu_trace_buffer(void)
1879 struct trace_buffer_struct
*buffers
;
1880 struct trace_buffer_struct
*sirq_buffers
;
1881 struct trace_buffer_struct
*irq_buffers
;
1882 struct trace_buffer_struct
*nmi_buffers
;
1884 buffers
= alloc_percpu(struct trace_buffer_struct
);
1888 sirq_buffers
= alloc_percpu(struct trace_buffer_struct
);
1892 irq_buffers
= alloc_percpu(struct trace_buffer_struct
);
1896 nmi_buffers
= alloc_percpu(struct trace_buffer_struct
);
1900 trace_percpu_buffer
= buffers
;
1901 trace_percpu_sirq_buffer
= sirq_buffers
;
1902 trace_percpu_irq_buffer
= irq_buffers
;
1903 trace_percpu_nmi_buffer
= nmi_buffers
;
1908 free_percpu(irq_buffers
);
1910 free_percpu(sirq_buffers
);
1912 free_percpu(buffers
);
1914 WARN(1, "Could not allocate percpu trace_printk buffer");
1918 static int buffers_allocated
;
1920 void trace_printk_init_buffers(void)
1922 if (buffers_allocated
)
1925 if (alloc_percpu_trace_buffer())
1928 pr_info("ftrace: Allocated trace_printk buffers\n");
1930 /* Expand the buffers to set size */
1931 tracing_update_buffers();
1933 buffers_allocated
= 1;
1936 * trace_printk_init_buffers() can be called by modules.
1937 * If that happens, then we need to start cmdline recording
1938 * directly here. If the global_trace.buffer is already
1939 * allocated here, then this was called by module code.
1941 if (global_trace
.trace_buffer
.buffer
)
1942 tracing_start_cmdline_record();
1945 void trace_printk_start_comm(void)
1947 /* Start tracing comms if trace printk is set */
1948 if (!buffers_allocated
)
1950 tracing_start_cmdline_record();
1953 static void trace_printk_start_stop_comm(int enabled
)
1955 if (!buffers_allocated
)
1959 tracing_start_cmdline_record();
1961 tracing_stop_cmdline_record();
1965 * trace_vbprintk - write binary msg to tracing buffer
1968 int trace_vbprintk(unsigned long ip
, const char *fmt
, va_list args
)
1970 struct ftrace_event_call
*call
= &event_bprint
;
1971 struct ring_buffer_event
*event
;
1972 struct ring_buffer
*buffer
;
1973 struct trace_array
*tr
= &global_trace
;
1974 struct bprint_entry
*entry
;
1975 unsigned long flags
;
1977 int len
= 0, size
, pc
;
1979 if (unlikely(tracing_selftest_running
|| tracing_disabled
))
1982 /* Don't pollute graph traces with trace_vprintk internals */
1983 pause_graph_tracing();
1985 pc
= preempt_count();
1986 preempt_disable_notrace();
1988 tbuffer
= get_trace_buf();
1994 len
= vbin_printf((u32
*)tbuffer
, TRACE_BUF_SIZE
/sizeof(int), fmt
, args
);
1996 if (len
> TRACE_BUF_SIZE
/sizeof(int) || len
< 0)
1999 local_save_flags(flags
);
2000 size
= sizeof(*entry
) + sizeof(u32
) * len
;
2001 buffer
= tr
->trace_buffer
.buffer
;
2002 event
= trace_buffer_lock_reserve(buffer
, TRACE_BPRINT
, size
,
2006 entry
= ring_buffer_event_data(event
);
2010 memcpy(entry
->buf
, tbuffer
, sizeof(u32
) * len
);
2011 if (!filter_check_discard(call
, entry
, buffer
, event
)) {
2012 __buffer_unlock_commit(buffer
, event
);
2013 ftrace_trace_stack(buffer
, flags
, 6, pc
);
2017 preempt_enable_notrace();
2018 unpause_graph_tracing();
2022 EXPORT_SYMBOL_GPL(trace_vbprintk
);
2025 __trace_array_vprintk(struct ring_buffer
*buffer
,
2026 unsigned long ip
, const char *fmt
, va_list args
)
2028 struct ftrace_event_call
*call
= &event_print
;
2029 struct ring_buffer_event
*event
;
2030 int len
= 0, size
, pc
;
2031 struct print_entry
*entry
;
2032 unsigned long flags
;
2035 if (tracing_disabled
|| tracing_selftest_running
)
2038 /* Don't pollute graph traces with trace_vprintk internals */
2039 pause_graph_tracing();
2041 pc
= preempt_count();
2042 preempt_disable_notrace();
2045 tbuffer
= get_trace_buf();
2051 len
= vsnprintf(tbuffer
, TRACE_BUF_SIZE
, fmt
, args
);
2052 if (len
> TRACE_BUF_SIZE
)
2055 local_save_flags(flags
);
2056 size
= sizeof(*entry
) + len
+ 1;
2057 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, size
,
2061 entry
= ring_buffer_event_data(event
);
2064 memcpy(&entry
->buf
, tbuffer
, len
);
2065 entry
->buf
[len
] = '\0';
2066 if (!filter_check_discard(call
, entry
, buffer
, event
)) {
2067 __buffer_unlock_commit(buffer
, event
);
2068 ftrace_trace_stack(buffer
, flags
, 6, pc
);
2071 preempt_enable_notrace();
2072 unpause_graph_tracing();
2077 int trace_array_vprintk(struct trace_array
*tr
,
2078 unsigned long ip
, const char *fmt
, va_list args
)
2080 return __trace_array_vprintk(tr
->trace_buffer
.buffer
, ip
, fmt
, args
);
2083 int trace_array_printk(struct trace_array
*tr
,
2084 unsigned long ip
, const char *fmt
, ...)
2089 if (!(trace_flags
& TRACE_ITER_PRINTK
))
2093 ret
= trace_array_vprintk(tr
, ip
, fmt
, ap
);
2098 int trace_array_printk_buf(struct ring_buffer
*buffer
,
2099 unsigned long ip
, const char *fmt
, ...)
2104 if (!(trace_flags
& TRACE_ITER_PRINTK
))
2108 ret
= __trace_array_vprintk(buffer
, ip
, fmt
, ap
);
2113 int trace_vprintk(unsigned long ip
, const char *fmt
, va_list args
)
2115 return trace_array_vprintk(&global_trace
, ip
, fmt
, args
);
2117 EXPORT_SYMBOL_GPL(trace_vprintk
);
2119 static void trace_iterator_increment(struct trace_iterator
*iter
)
2121 struct ring_buffer_iter
*buf_iter
= trace_buffer_iter(iter
, iter
->cpu
);
2125 ring_buffer_read(buf_iter
, NULL
);
2128 static struct trace_entry
*
2129 peek_next_entry(struct trace_iterator
*iter
, int cpu
, u64
*ts
,
2130 unsigned long *lost_events
)
2132 struct ring_buffer_event
*event
;
2133 struct ring_buffer_iter
*buf_iter
= trace_buffer_iter(iter
, cpu
);
2136 event
= ring_buffer_iter_peek(buf_iter
, ts
);
2138 event
= ring_buffer_peek(iter
->trace_buffer
->buffer
, cpu
, ts
,
2142 iter
->ent_size
= ring_buffer_event_length(event
);
2143 return ring_buffer_event_data(event
);
2149 static struct trace_entry
*
2150 __find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
,
2151 unsigned long *missing_events
, u64
*ent_ts
)
2153 struct ring_buffer
*buffer
= iter
->trace_buffer
->buffer
;
2154 struct trace_entry
*ent
, *next
= NULL
;
2155 unsigned long lost_events
= 0, next_lost
= 0;
2156 int cpu_file
= iter
->cpu_file
;
2157 u64 next_ts
= 0, ts
;
2163 * If we are in a per_cpu trace file, don't bother by iterating over
2164 * all cpu and peek directly.
2166 if (cpu_file
> RING_BUFFER_ALL_CPUS
) {
2167 if (ring_buffer_empty_cpu(buffer
, cpu_file
))
2169 ent
= peek_next_entry(iter
, cpu_file
, ent_ts
, missing_events
);
2171 *ent_cpu
= cpu_file
;
2176 for_each_tracing_cpu(cpu
) {
2178 if (ring_buffer_empty_cpu(buffer
, cpu
))
2181 ent
= peek_next_entry(iter
, cpu
, &ts
, &lost_events
);
2184 * Pick the entry with the smallest timestamp:
2186 if (ent
&& (!next
|| ts
< next_ts
)) {
2190 next_lost
= lost_events
;
2191 next_size
= iter
->ent_size
;
2195 iter
->ent_size
= next_size
;
2198 *ent_cpu
= next_cpu
;
2204 *missing_events
= next_lost
;
2209 /* Find the next real entry, without updating the iterator itself */
2210 struct trace_entry
*trace_find_next_entry(struct trace_iterator
*iter
,
2211 int *ent_cpu
, u64
*ent_ts
)
2213 return __find_next_entry(iter
, ent_cpu
, NULL
, ent_ts
);
2216 /* Find the next real entry, and increment the iterator to the next entry */
2217 void *trace_find_next_entry_inc(struct trace_iterator
*iter
)
2219 iter
->ent
= __find_next_entry(iter
, &iter
->cpu
,
2220 &iter
->lost_events
, &iter
->ts
);
2223 trace_iterator_increment(iter
);
2225 return iter
->ent
? iter
: NULL
;
2228 static void trace_consume(struct trace_iterator
*iter
)
2230 ring_buffer_consume(iter
->trace_buffer
->buffer
, iter
->cpu
, &iter
->ts
,
2231 &iter
->lost_events
);
2234 static void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
2236 struct trace_iterator
*iter
= m
->private;
2240 WARN_ON_ONCE(iter
->leftover
);
2244 /* can't go backwards */
2249 ent
= trace_find_next_entry_inc(iter
);
2253 while (ent
&& iter
->idx
< i
)
2254 ent
= trace_find_next_entry_inc(iter
);
2261 void tracing_iter_reset(struct trace_iterator
*iter
, int cpu
)
2263 struct ring_buffer_event
*event
;
2264 struct ring_buffer_iter
*buf_iter
;
2265 unsigned long entries
= 0;
2268 per_cpu_ptr(iter
->trace_buffer
->data
, cpu
)->skipped_entries
= 0;
2270 buf_iter
= trace_buffer_iter(iter
, cpu
);
2274 ring_buffer_iter_reset(buf_iter
);
2277 * We could have the case with the max latency tracers
2278 * that a reset never took place on a cpu. This is evident
2279 * by the timestamp being before the start of the buffer.
2281 while ((event
= ring_buffer_iter_peek(buf_iter
, &ts
))) {
2282 if (ts
>= iter
->trace_buffer
->time_start
)
2285 ring_buffer_read(buf_iter
, NULL
);
2288 per_cpu_ptr(iter
->trace_buffer
->data
, cpu
)->skipped_entries
= entries
;
2292 * The current tracer is copied to avoid a global locking
2295 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
2297 struct trace_iterator
*iter
= m
->private;
2298 struct trace_array
*tr
= iter
->tr
;
2299 int cpu_file
= iter
->cpu_file
;
2305 * copy the tracer to avoid using a global lock all around.
2306 * iter->trace is a copy of current_trace, the pointer to the
2307 * name may be used instead of a strcmp(), as iter->trace->name
2308 * will point to the same string as current_trace->name.
2310 mutex_lock(&trace_types_lock
);
2311 if (unlikely(tr
->current_trace
&& iter
->trace
->name
!= tr
->current_trace
->name
))
2312 *iter
->trace
= *tr
->current_trace
;
2313 mutex_unlock(&trace_types_lock
);
2315 #ifdef CONFIG_TRACER_MAX_TRACE
2316 if (iter
->snapshot
&& iter
->trace
->use_max_tr
)
2317 return ERR_PTR(-EBUSY
);
2320 if (!iter
->snapshot
)
2321 atomic_inc(&trace_record_cmdline_disabled
);
2323 if (*pos
!= iter
->pos
) {
2328 if (cpu_file
== RING_BUFFER_ALL_CPUS
) {
2329 for_each_tracing_cpu(cpu
)
2330 tracing_iter_reset(iter
, cpu
);
2332 tracing_iter_reset(iter
, cpu_file
);
2335 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
2340 * If we overflowed the seq_file before, then we want
2341 * to just reuse the trace_seq buffer again.
2347 p
= s_next(m
, p
, &l
);
2351 trace_event_read_lock();
2352 trace_access_lock(cpu_file
);
2356 static void s_stop(struct seq_file
*m
, void *p
)
2358 struct trace_iterator
*iter
= m
->private;
2360 #ifdef CONFIG_TRACER_MAX_TRACE
2361 if (iter
->snapshot
&& iter
->trace
->use_max_tr
)
2365 if (!iter
->snapshot
)
2366 atomic_dec(&trace_record_cmdline_disabled
);
2368 trace_access_unlock(iter
->cpu_file
);
2369 trace_event_read_unlock();
2373 get_total_entries(struct trace_buffer
*buf
,
2374 unsigned long *total
, unsigned long *entries
)
2376 unsigned long count
;
2382 for_each_tracing_cpu(cpu
) {
2383 count
= ring_buffer_entries_cpu(buf
->buffer
, cpu
);
2385 * If this buffer has skipped entries, then we hold all
2386 * entries for the trace and we need to ignore the
2387 * ones before the time stamp.
2389 if (per_cpu_ptr(buf
->data
, cpu
)->skipped_entries
) {
2390 count
-= per_cpu_ptr(buf
->data
, cpu
)->skipped_entries
;
2391 /* total is the same as the entries */
2395 ring_buffer_overrun_cpu(buf
->buffer
, cpu
);
2400 static void print_lat_help_header(struct seq_file
*m
)
2402 seq_puts(m
, "# _------=> CPU# \n");
2403 seq_puts(m
, "# / _-----=> irqs-off \n");
2404 seq_puts(m
, "# | / _----=> need-resched \n");
2405 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
2406 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
2407 seq_puts(m
, "# |||| / delay \n");
2408 seq_puts(m
, "# cmd pid ||||| time | caller \n");
2409 seq_puts(m
, "# \\ / ||||| \\ | / \n");
2412 static void print_event_info(struct trace_buffer
*buf
, struct seq_file
*m
)
2414 unsigned long total
;
2415 unsigned long entries
;
2417 get_total_entries(buf
, &total
, &entries
);
2418 seq_printf(m
, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
2419 entries
, total
, num_online_cpus());
2423 static void print_func_help_header(struct trace_buffer
*buf
, struct seq_file
*m
)
2425 print_event_info(buf
, m
);
2426 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
2427 seq_puts(m
, "# | | | | |\n");
2430 static void print_func_help_header_irq(struct trace_buffer
*buf
, struct seq_file
*m
)
2432 print_event_info(buf
, m
);
2433 seq_puts(m
, "# _-----=> irqs-off\n");
2434 seq_puts(m
, "# / _----=> need-resched\n");
2435 seq_puts(m
, "# | / _---=> hardirq/softirq\n");
2436 seq_puts(m
, "# || / _--=> preempt-depth\n");
2437 seq_puts(m
, "# ||| / delay\n");
2438 seq_puts(m
, "# TASK-PID CPU# |||| TIMESTAMP FUNCTION\n");
2439 seq_puts(m
, "# | | | |||| | |\n");
2443 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
2445 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
2446 struct trace_buffer
*buf
= iter
->trace_buffer
;
2447 struct trace_array_cpu
*data
= per_cpu_ptr(buf
->data
, buf
->cpu
);
2448 struct tracer
*type
= iter
->trace
;
2449 unsigned long entries
;
2450 unsigned long total
;
2451 const char *name
= "preemption";
2455 get_total_entries(buf
, &total
, &entries
);
2457 seq_printf(m
, "# %s latency trace v1.1.5 on %s\n",
2459 seq_puts(m
, "# -----------------------------------"
2460 "---------------------------------\n");
2461 seq_printf(m
, "# latency: %lu us, #%lu/%lu, CPU#%d |"
2462 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
2463 nsecs_to_usecs(data
->saved_latency
),
2467 #if defined(CONFIG_PREEMPT_NONE)
2469 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
2471 #elif defined(CONFIG_PREEMPT)
2476 /* These are reserved for later use */
2479 seq_printf(m
, " #P:%d)\n", num_online_cpus());
2483 seq_puts(m
, "# -----------------\n");
2484 seq_printf(m
, "# | task: %.16s-%d "
2485 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
2486 data
->comm
, data
->pid
,
2487 from_kuid_munged(seq_user_ns(m
), data
->uid
), data
->nice
,
2488 data
->policy
, data
->rt_priority
);
2489 seq_puts(m
, "# -----------------\n");
2491 if (data
->critical_start
) {
2492 seq_puts(m
, "# => started at: ");
2493 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
2494 trace_print_seq(m
, &iter
->seq
);
2495 seq_puts(m
, "\n# => ended at: ");
2496 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
2497 trace_print_seq(m
, &iter
->seq
);
2498 seq_puts(m
, "\n#\n");
2504 static void test_cpu_buff_start(struct trace_iterator
*iter
)
2506 struct trace_seq
*s
= &iter
->seq
;
2508 if (!(trace_flags
& TRACE_ITER_ANNOTATE
))
2511 if (!(iter
->iter_flags
& TRACE_FILE_ANNOTATE
))
2514 if (cpumask_test_cpu(iter
->cpu
, iter
->started
))
2517 if (per_cpu_ptr(iter
->trace_buffer
->data
, iter
->cpu
)->skipped_entries
)
2520 cpumask_set_cpu(iter
->cpu
, iter
->started
);
2522 /* Don't print started cpu buffer for the first entry of the trace */
2524 trace_seq_printf(s
, "##### CPU %u buffer started ####\n",
2528 static enum print_line_t
print_trace_fmt(struct trace_iterator
*iter
)
2530 struct trace_seq
*s
= &iter
->seq
;
2531 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
2532 struct trace_entry
*entry
;
2533 struct trace_event
*event
;
2537 test_cpu_buff_start(iter
);
2539 event
= ftrace_find_event(entry
->type
);
2541 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2542 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
2543 if (!trace_print_lat_context(iter
))
2546 if (!trace_print_context(iter
))
2552 return event
->funcs
->trace(iter
, sym_flags
, event
);
2554 if (!trace_seq_printf(s
, "Unknown type %d\n", entry
->type
))
2557 return TRACE_TYPE_HANDLED
;
2559 return TRACE_TYPE_PARTIAL_LINE
;
2562 static enum print_line_t
print_raw_fmt(struct trace_iterator
*iter
)
2564 struct trace_seq
*s
= &iter
->seq
;
2565 struct trace_entry
*entry
;
2566 struct trace_event
*event
;
2570 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2571 if (!trace_seq_printf(s
, "%d %d %llu ",
2572 entry
->pid
, iter
->cpu
, iter
->ts
))
2576 event
= ftrace_find_event(entry
->type
);
2578 return event
->funcs
->raw(iter
, 0, event
);
2580 if (!trace_seq_printf(s
, "%d ?\n", entry
->type
))
2583 return TRACE_TYPE_HANDLED
;
2585 return TRACE_TYPE_PARTIAL_LINE
;
2588 static enum print_line_t
print_hex_fmt(struct trace_iterator
*iter
)
2590 struct trace_seq
*s
= &iter
->seq
;
2591 unsigned char newline
= '\n';
2592 struct trace_entry
*entry
;
2593 struct trace_event
*event
;
2597 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2598 SEQ_PUT_HEX_FIELD_RET(s
, entry
->pid
);
2599 SEQ_PUT_HEX_FIELD_RET(s
, iter
->cpu
);
2600 SEQ_PUT_HEX_FIELD_RET(s
, iter
->ts
);
2603 event
= ftrace_find_event(entry
->type
);
2605 enum print_line_t ret
= event
->funcs
->hex(iter
, 0, event
);
2606 if (ret
!= TRACE_TYPE_HANDLED
)
2610 SEQ_PUT_FIELD_RET(s
, newline
);
2612 return TRACE_TYPE_HANDLED
;
2615 static enum print_line_t
print_bin_fmt(struct trace_iterator
*iter
)
2617 struct trace_seq
*s
= &iter
->seq
;
2618 struct trace_entry
*entry
;
2619 struct trace_event
*event
;
2623 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2624 SEQ_PUT_FIELD_RET(s
, entry
->pid
);
2625 SEQ_PUT_FIELD_RET(s
, iter
->cpu
);
2626 SEQ_PUT_FIELD_RET(s
, iter
->ts
);
2629 event
= ftrace_find_event(entry
->type
);
2630 return event
? event
->funcs
->binary(iter
, 0, event
) :
2634 int trace_empty(struct trace_iterator
*iter
)
2636 struct ring_buffer_iter
*buf_iter
;
2639 /* If we are looking at one CPU buffer, only check that one */
2640 if (iter
->cpu_file
!= RING_BUFFER_ALL_CPUS
) {
2641 cpu
= iter
->cpu_file
;
2642 buf_iter
= trace_buffer_iter(iter
, cpu
);
2644 if (!ring_buffer_iter_empty(buf_iter
))
2647 if (!ring_buffer_empty_cpu(iter
->trace_buffer
->buffer
, cpu
))
2653 for_each_tracing_cpu(cpu
) {
2654 buf_iter
= trace_buffer_iter(iter
, cpu
);
2656 if (!ring_buffer_iter_empty(buf_iter
))
2659 if (!ring_buffer_empty_cpu(iter
->trace_buffer
->buffer
, cpu
))
2667 /* Called with trace_event_read_lock() held. */
2668 enum print_line_t
print_trace_line(struct trace_iterator
*iter
)
2670 enum print_line_t ret
;
2672 if (iter
->lost_events
&&
2673 !trace_seq_printf(&iter
->seq
, "CPU:%d [LOST %lu EVENTS]\n",
2674 iter
->cpu
, iter
->lost_events
))
2675 return TRACE_TYPE_PARTIAL_LINE
;
2677 if (iter
->trace
&& iter
->trace
->print_line
) {
2678 ret
= iter
->trace
->print_line(iter
);
2679 if (ret
!= TRACE_TYPE_UNHANDLED
)
2683 if (iter
->ent
->type
== TRACE_BPUTS
&&
2684 trace_flags
& TRACE_ITER_PRINTK
&&
2685 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2686 return trace_print_bputs_msg_only(iter
);
2688 if (iter
->ent
->type
== TRACE_BPRINT
&&
2689 trace_flags
& TRACE_ITER_PRINTK
&&
2690 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2691 return trace_print_bprintk_msg_only(iter
);
2693 if (iter
->ent
->type
== TRACE_PRINT
&&
2694 trace_flags
& TRACE_ITER_PRINTK
&&
2695 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2696 return trace_print_printk_msg_only(iter
);
2698 if (trace_flags
& TRACE_ITER_BIN
)
2699 return print_bin_fmt(iter
);
2701 if (trace_flags
& TRACE_ITER_HEX
)
2702 return print_hex_fmt(iter
);
2704 if (trace_flags
& TRACE_ITER_RAW
)
2705 return print_raw_fmt(iter
);
2707 return print_trace_fmt(iter
);
2710 void trace_latency_header(struct seq_file
*m
)
2712 struct trace_iterator
*iter
= m
->private;
2714 /* print nothing if the buffers are empty */
2715 if (trace_empty(iter
))
2718 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
)
2719 print_trace_header(m
, iter
);
2721 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2722 print_lat_help_header(m
);
2725 void trace_default_header(struct seq_file
*m
)
2727 struct trace_iterator
*iter
= m
->private;
2729 if (!(trace_flags
& TRACE_ITER_CONTEXT_INFO
))
2732 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
2733 /* print nothing if the buffers are empty */
2734 if (trace_empty(iter
))
2736 print_trace_header(m
, iter
);
2737 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2738 print_lat_help_header(m
);
2740 if (!(trace_flags
& TRACE_ITER_VERBOSE
)) {
2741 if (trace_flags
& TRACE_ITER_IRQ_INFO
)
2742 print_func_help_header_irq(iter
->trace_buffer
, m
);
2744 print_func_help_header(iter
->trace_buffer
, m
);
2749 static void test_ftrace_alive(struct seq_file
*m
)
2751 if (!ftrace_is_dead())
2753 seq_printf(m
, "# WARNING: FUNCTION TRACING IS CORRUPTED\n");
2754 seq_printf(m
, "# MAY BE MISSING FUNCTION EVENTS\n");
2757 #ifdef CONFIG_TRACER_MAX_TRACE
2758 static void show_snapshot_main_help(struct seq_file
*m
)
2760 seq_printf(m
, "# echo 0 > snapshot : Clears and frees snapshot buffer\n");
2761 seq_printf(m
, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
2762 seq_printf(m
, "# Takes a snapshot of the main buffer.\n");
2763 seq_printf(m
, "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate)\n");
2764 seq_printf(m
, "# (Doesn't have to be '2' works with any number that\n");
2765 seq_printf(m
, "# is not a '0' or '1')\n");
2768 static void show_snapshot_percpu_help(struct seq_file
*m
)
2770 seq_printf(m
, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
2771 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
2772 seq_printf(m
, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
2773 seq_printf(m
, "# Takes a snapshot of the main buffer for this cpu.\n");
2775 seq_printf(m
, "# echo 1 > snapshot : Not supported with this kernel.\n");
2776 seq_printf(m
, "# Must use main snapshot file to allocate.\n");
2778 seq_printf(m
, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n");
2779 seq_printf(m
, "# (Doesn't have to be '2' works with any number that\n");
2780 seq_printf(m
, "# is not a '0' or '1')\n");
2783 static void print_snapshot_help(struct seq_file
*m
, struct trace_iterator
*iter
)
2785 if (iter
->tr
->allocated_snapshot
)
2786 seq_printf(m
, "#\n# * Snapshot is allocated *\n#\n");
2788 seq_printf(m
, "#\n# * Snapshot is freed *\n#\n");
2790 seq_printf(m
, "# Snapshot commands:\n");
2791 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
)
2792 show_snapshot_main_help(m
);
2794 show_snapshot_percpu_help(m
);
2797 /* Should never be called */
2798 static inline void print_snapshot_help(struct seq_file
*m
, struct trace_iterator
*iter
) { }
2801 static int s_show(struct seq_file
*m
, void *v
)
2803 struct trace_iterator
*iter
= v
;
2806 if (iter
->ent
== NULL
) {
2808 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
2810 test_ftrace_alive(m
);
2812 if (iter
->snapshot
&& trace_empty(iter
))
2813 print_snapshot_help(m
, iter
);
2814 else if (iter
->trace
&& iter
->trace
->print_header
)
2815 iter
->trace
->print_header(m
);
2817 trace_default_header(m
);
2819 } else if (iter
->leftover
) {
2821 * If we filled the seq_file buffer earlier, we
2822 * want to just show it now.
2824 ret
= trace_print_seq(m
, &iter
->seq
);
2826 /* ret should this time be zero, but you never know */
2827 iter
->leftover
= ret
;
2830 print_trace_line(iter
);
2831 ret
= trace_print_seq(m
, &iter
->seq
);
2833 * If we overflow the seq_file buffer, then it will
2834 * ask us for this data again at start up.
2836 * ret is 0 if seq_file write succeeded.
2839 iter
->leftover
= ret
;
2846 * Should be used after trace_array_get(), trace_types_lock
2847 * ensures that i_cdev was already initialized.
2849 static inline int tracing_get_cpu(struct inode
*inode
)
2851 if (inode
->i_cdev
) /* See trace_create_cpu_file() */
2852 return (long)inode
->i_cdev
- 1;
2853 return RING_BUFFER_ALL_CPUS
;
2856 static const struct seq_operations tracer_seq_ops
= {
2863 static struct trace_iterator
*
2864 __tracing_open(struct inode
*inode
, struct file
*file
, bool snapshot
)
2866 struct trace_array
*tr
= inode
->i_private
;
2867 struct trace_iterator
*iter
;
2870 if (tracing_disabled
)
2871 return ERR_PTR(-ENODEV
);
2873 iter
= __seq_open_private(file
, &tracer_seq_ops
, sizeof(*iter
));
2875 return ERR_PTR(-ENOMEM
);
2877 iter
->buffer_iter
= kzalloc(sizeof(*iter
->buffer_iter
) * num_possible_cpus(),
2879 if (!iter
->buffer_iter
)
2883 * We make a copy of the current tracer to avoid concurrent
2884 * changes on it while we are reading.
2886 mutex_lock(&trace_types_lock
);
2887 iter
->trace
= kzalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
2891 *iter
->trace
= *tr
->current_trace
;
2893 if (!zalloc_cpumask_var(&iter
->started
, GFP_KERNEL
))
2898 #ifdef CONFIG_TRACER_MAX_TRACE
2899 /* Currently only the top directory has a snapshot */
2900 if (tr
->current_trace
->print_max
|| snapshot
)
2901 iter
->trace_buffer
= &tr
->max_buffer
;
2904 iter
->trace_buffer
= &tr
->trace_buffer
;
2905 iter
->snapshot
= snapshot
;
2907 iter
->cpu_file
= tracing_get_cpu(inode
);
2908 mutex_init(&iter
->mutex
);
2910 /* Notify the tracer early; before we stop tracing. */
2911 if (iter
->trace
&& iter
->trace
->open
)
2912 iter
->trace
->open(iter
);
2914 /* Annotate start of buffers if we had overruns */
2915 if (ring_buffer_overruns(iter
->trace_buffer
->buffer
))
2916 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
2918 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
2919 if (trace_clocks
[tr
->clock_id
].in_ns
)
2920 iter
->iter_flags
|= TRACE_FILE_TIME_IN_NS
;
2922 /* stop the trace while dumping if we are not opening "snapshot" */
2923 if (!iter
->snapshot
)
2924 tracing_stop_tr(tr
);
2926 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
) {
2927 for_each_tracing_cpu(cpu
) {
2928 iter
->buffer_iter
[cpu
] =
2929 ring_buffer_read_prepare(iter
->trace_buffer
->buffer
, cpu
);
2931 ring_buffer_read_prepare_sync();
2932 for_each_tracing_cpu(cpu
) {
2933 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2934 tracing_iter_reset(iter
, cpu
);
2937 cpu
= iter
->cpu_file
;
2938 iter
->buffer_iter
[cpu
] =
2939 ring_buffer_read_prepare(iter
->trace_buffer
->buffer
, cpu
);
2940 ring_buffer_read_prepare_sync();
2941 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2942 tracing_iter_reset(iter
, cpu
);
2945 mutex_unlock(&trace_types_lock
);
2950 mutex_unlock(&trace_types_lock
);
2952 kfree(iter
->buffer_iter
);
2954 seq_release_private(inode
, file
);
2955 return ERR_PTR(-ENOMEM
);
2958 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
2960 if (tracing_disabled
)
2963 filp
->private_data
= inode
->i_private
;
2968 * Open and update trace_array ref count.
2969 * Must have the current trace_array passed to it.
2971 static int tracing_open_generic_tr(struct inode
*inode
, struct file
*filp
)
2973 struct trace_array
*tr
= inode
->i_private
;
2975 if (tracing_disabled
)
2978 if (trace_array_get(tr
) < 0)
2981 filp
->private_data
= inode
->i_private
;
2986 static int tracing_release(struct inode
*inode
, struct file
*file
)
2988 struct trace_array
*tr
= inode
->i_private
;
2989 struct seq_file
*m
= file
->private_data
;
2990 struct trace_iterator
*iter
;
2993 if (!(file
->f_mode
& FMODE_READ
)) {
2994 trace_array_put(tr
);
2998 /* Writes do not use seq_file */
3000 mutex_lock(&trace_types_lock
);
3002 for_each_tracing_cpu(cpu
) {
3003 if (iter
->buffer_iter
[cpu
])
3004 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
3007 if (iter
->trace
&& iter
->trace
->close
)
3008 iter
->trace
->close(iter
);
3010 if (!iter
->snapshot
)
3011 /* reenable tracing if it was previously enabled */
3012 tracing_start_tr(tr
);
3014 __trace_array_put(tr
);
3016 mutex_unlock(&trace_types_lock
);
3018 mutex_destroy(&iter
->mutex
);
3019 free_cpumask_var(iter
->started
);
3021 kfree(iter
->buffer_iter
);
3022 seq_release_private(inode
, file
);
3027 static int tracing_release_generic_tr(struct inode
*inode
, struct file
*file
)
3029 struct trace_array
*tr
= inode
->i_private
;
3031 trace_array_put(tr
);
3035 static int tracing_single_release_tr(struct inode
*inode
, struct file
*file
)
3037 struct trace_array
*tr
= inode
->i_private
;
3039 trace_array_put(tr
);
3041 return single_release(inode
, file
);
3044 static int tracing_open(struct inode
*inode
, struct file
*file
)
3046 struct trace_array
*tr
= inode
->i_private
;
3047 struct trace_iterator
*iter
;
3050 if (trace_array_get(tr
) < 0)
3053 /* If this file was open for write, then erase contents */
3054 if ((file
->f_mode
& FMODE_WRITE
) && (file
->f_flags
& O_TRUNC
)) {
3055 int cpu
= tracing_get_cpu(inode
);
3057 if (cpu
== RING_BUFFER_ALL_CPUS
)
3058 tracing_reset_online_cpus(&tr
->trace_buffer
);
3060 tracing_reset(&tr
->trace_buffer
, cpu
);
3063 if (file
->f_mode
& FMODE_READ
) {
3064 iter
= __tracing_open(inode
, file
, false);
3066 ret
= PTR_ERR(iter
);
3067 else if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
3068 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
3072 trace_array_put(tr
);
3078 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
3080 struct tracer
*t
= v
;
3090 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
3095 mutex_lock(&trace_types_lock
);
3096 for (t
= trace_types
; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
3102 static void t_stop(struct seq_file
*m
, void *p
)
3104 mutex_unlock(&trace_types_lock
);
3107 static int t_show(struct seq_file
*m
, void *v
)
3109 struct tracer
*t
= v
;
3114 seq_printf(m
, "%s", t
->name
);
3123 static const struct seq_operations show_traces_seq_ops
= {
3130 static int show_traces_open(struct inode
*inode
, struct file
*file
)
3132 if (tracing_disabled
)
3135 return seq_open(file
, &show_traces_seq_ops
);
3139 tracing_write_stub(struct file
*filp
, const char __user
*ubuf
,
3140 size_t count
, loff_t
*ppos
)
3145 static loff_t
tracing_seek(struct file
*file
, loff_t offset
, int origin
)
3147 if (file
->f_mode
& FMODE_READ
)
3148 return seq_lseek(file
, offset
, origin
);
3153 static const struct file_operations tracing_fops
= {
3154 .open
= tracing_open
,
3156 .write
= tracing_write_stub
,
3157 .llseek
= tracing_seek
,
3158 .release
= tracing_release
,
3161 static const struct file_operations show_traces_fops
= {
3162 .open
= show_traces_open
,
3164 .release
= seq_release
,
3165 .llseek
= seq_lseek
,
3169 * The tracer itself will not take this lock, but still we want
3170 * to provide a consistent cpumask to user-space:
3172 static DEFINE_MUTEX(tracing_cpumask_update_lock
);
3175 * Temporary storage for the character representation of the
3176 * CPU bitmask (and one more byte for the newline):
3178 static char mask_str
[NR_CPUS
+ 1];
3181 tracing_cpumask_read(struct file
*filp
, char __user
*ubuf
,
3182 size_t count
, loff_t
*ppos
)
3184 struct trace_array
*tr
= file_inode(filp
)->i_private
;
3187 mutex_lock(&tracing_cpumask_update_lock
);
3189 len
= cpumask_scnprintf(mask_str
, count
, tr
->tracing_cpumask
);
3190 if (count
- len
< 2) {
3194 len
+= sprintf(mask_str
+ len
, "\n");
3195 count
= simple_read_from_buffer(ubuf
, count
, ppos
, mask_str
, NR_CPUS
+1);
3198 mutex_unlock(&tracing_cpumask_update_lock
);
3204 tracing_cpumask_write(struct file
*filp
, const char __user
*ubuf
,
3205 size_t count
, loff_t
*ppos
)
3207 struct trace_array
*tr
= file_inode(filp
)->i_private
;
3208 cpumask_var_t tracing_cpumask_new
;
3211 if (!alloc_cpumask_var(&tracing_cpumask_new
, GFP_KERNEL
))
3214 err
= cpumask_parse_user(ubuf
, count
, tracing_cpumask_new
);
3218 mutex_lock(&tracing_cpumask_update_lock
);
3220 local_irq_disable();
3221 arch_spin_lock(&ftrace_max_lock
);
3222 for_each_tracing_cpu(cpu
) {
3224 * Increase/decrease the disabled counter if we are
3225 * about to flip a bit in the cpumask:
3227 if (cpumask_test_cpu(cpu
, tr
->tracing_cpumask
) &&
3228 !cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
3229 atomic_inc(&per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->disabled
);
3230 ring_buffer_record_disable_cpu(tr
->trace_buffer
.buffer
, cpu
);
3232 if (!cpumask_test_cpu(cpu
, tr
->tracing_cpumask
) &&
3233 cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
3234 atomic_dec(&per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->disabled
);
3235 ring_buffer_record_enable_cpu(tr
->trace_buffer
.buffer
, cpu
);
3238 arch_spin_unlock(&ftrace_max_lock
);
3241 cpumask_copy(tr
->tracing_cpumask
, tracing_cpumask_new
);
3243 mutex_unlock(&tracing_cpumask_update_lock
);
3244 free_cpumask_var(tracing_cpumask_new
);
3249 free_cpumask_var(tracing_cpumask_new
);
3254 static const struct file_operations tracing_cpumask_fops
= {
3255 .open
= tracing_open_generic_tr
,
3256 .read
= tracing_cpumask_read
,
3257 .write
= tracing_cpumask_write
,
3258 .release
= tracing_release_generic_tr
,
3259 .llseek
= generic_file_llseek
,
3262 static int tracing_trace_options_show(struct seq_file
*m
, void *v
)
3264 struct tracer_opt
*trace_opts
;
3265 struct trace_array
*tr
= m
->private;
3269 mutex_lock(&trace_types_lock
);
3270 tracer_flags
= tr
->current_trace
->flags
->val
;
3271 trace_opts
= tr
->current_trace
->flags
->opts
;
3273 for (i
= 0; trace_options
[i
]; i
++) {
3274 if (trace_flags
& (1 << i
))
3275 seq_printf(m
, "%s\n", trace_options
[i
]);
3277 seq_printf(m
, "no%s\n", trace_options
[i
]);
3280 for (i
= 0; trace_opts
[i
].name
; i
++) {
3281 if (tracer_flags
& trace_opts
[i
].bit
)
3282 seq_printf(m
, "%s\n", trace_opts
[i
].name
);
3284 seq_printf(m
, "no%s\n", trace_opts
[i
].name
);
3286 mutex_unlock(&trace_types_lock
);
3291 static int __set_tracer_option(struct tracer
*trace
,
3292 struct tracer_flags
*tracer_flags
,
3293 struct tracer_opt
*opts
, int neg
)
3297 ret
= trace
->set_flag(tracer_flags
->val
, opts
->bit
, !neg
);
3302 tracer_flags
->val
&= ~opts
->bit
;
3304 tracer_flags
->val
|= opts
->bit
;
3308 /* Try to assign a tracer specific option */
3309 static int set_tracer_option(struct tracer
*trace
, char *cmp
, int neg
)
3311 struct tracer_flags
*tracer_flags
= trace
->flags
;
3312 struct tracer_opt
*opts
= NULL
;
3315 for (i
= 0; tracer_flags
->opts
[i
].name
; i
++) {
3316 opts
= &tracer_flags
->opts
[i
];
3318 if (strcmp(cmp
, opts
->name
) == 0)
3319 return __set_tracer_option(trace
, trace
->flags
,
3326 /* Some tracers require overwrite to stay enabled */
3327 int trace_keep_overwrite(struct tracer
*tracer
, u32 mask
, int set
)
3329 if (tracer
->enabled
&& (mask
& TRACE_ITER_OVERWRITE
) && !set
)
3335 int set_tracer_flag(struct trace_array
*tr
, unsigned int mask
, int enabled
)
3337 /* do nothing if flag is already set */
3338 if (!!(trace_flags
& mask
) == !!enabled
)
3341 /* Give the tracer a chance to approve the change */
3342 if (tr
->current_trace
->flag_changed
)
3343 if (tr
->current_trace
->flag_changed(tr
->current_trace
, mask
, !!enabled
))
3347 trace_flags
|= mask
;
3349 trace_flags
&= ~mask
;
3351 if (mask
== TRACE_ITER_RECORD_CMD
)
3352 trace_event_enable_cmd_record(enabled
);
3354 if (mask
== TRACE_ITER_OVERWRITE
) {
3355 ring_buffer_change_overwrite(tr
->trace_buffer
.buffer
, enabled
);
3356 #ifdef CONFIG_TRACER_MAX_TRACE
3357 ring_buffer_change_overwrite(tr
->max_buffer
.buffer
, enabled
);
3361 if (mask
== TRACE_ITER_PRINTK
)
3362 trace_printk_start_stop_comm(enabled
);
3367 static int trace_set_options(struct trace_array
*tr
, char *option
)
3374 cmp
= strstrip(option
);
3376 if (strncmp(cmp
, "no", 2) == 0) {
3381 mutex_lock(&trace_types_lock
);
3383 for (i
= 0; trace_options
[i
]; i
++) {
3384 if (strcmp(cmp
, trace_options
[i
]) == 0) {
3385 ret
= set_tracer_flag(tr
, 1 << i
, !neg
);
3390 /* If no option could be set, test the specific tracer options */
3391 if (!trace_options
[i
])
3392 ret
= set_tracer_option(tr
->current_trace
, cmp
, neg
);
3394 mutex_unlock(&trace_types_lock
);
3400 tracing_trace_options_write(struct file
*filp
, const char __user
*ubuf
,
3401 size_t cnt
, loff_t
*ppos
)
3403 struct seq_file
*m
= filp
->private_data
;
3404 struct trace_array
*tr
= m
->private;
3408 if (cnt
>= sizeof(buf
))
3411 if (copy_from_user(&buf
, ubuf
, cnt
))
3416 ret
= trace_set_options(tr
, buf
);
3425 static int tracing_trace_options_open(struct inode
*inode
, struct file
*file
)
3427 struct trace_array
*tr
= inode
->i_private
;
3430 if (tracing_disabled
)
3433 if (trace_array_get(tr
) < 0)
3436 ret
= single_open(file
, tracing_trace_options_show
, inode
->i_private
);
3438 trace_array_put(tr
);
3443 static const struct file_operations tracing_iter_fops
= {
3444 .open
= tracing_trace_options_open
,
3446 .llseek
= seq_lseek
,
3447 .release
= tracing_single_release_tr
,
3448 .write
= tracing_trace_options_write
,
3451 static const char readme_msg
[] =
3452 "tracing mini-HOWTO:\n\n"
3453 "# echo 0 > tracing_on : quick way to disable tracing\n"
3454 "# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
3455 " Important files:\n"
3456 " trace\t\t\t- The static contents of the buffer\n"
3457 "\t\t\t To clear the buffer write into this file: echo > trace\n"
3458 " trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
3459 " current_tracer\t- function and latency tracers\n"
3460 " available_tracers\t- list of configured tracers for current_tracer\n"
3461 " buffer_size_kb\t- view and modify size of per cpu buffer\n"
3462 " buffer_total_size_kb - view total size of all cpu buffers\n\n"
3463 " trace_clock\t\t-change the clock used to order events\n"
3464 " local: Per cpu clock but may not be synced across CPUs\n"
3465 " global: Synced across CPUs but slows tracing down.\n"
3466 " counter: Not a clock, but just an increment\n"
3467 " uptime: Jiffy counter from time of boot\n"
3468 " perf: Same clock that perf events use\n"
3469 #ifdef CONFIG_X86_64
3470 " x86-tsc: TSC cycle counter\n"
3472 "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
3473 " tracing_cpumask\t- Limit which CPUs to trace\n"
3474 " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
3475 "\t\t\t Remove sub-buffer with rmdir\n"
3476 " trace_options\t\t- Set format or modify how tracing happens\n"
3477 "\t\t\t Disable an option by adding a suffix 'no' to the option name\n"
3478 #ifdef CONFIG_DYNAMIC_FTRACE
3479 "\n available_filter_functions - list of functions that can be filtered on\n"
3480 " set_ftrace_filter\t- echo function name in here to only trace these functions\n"
3481 " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3482 " modules: Can select a group via module\n"
3483 " Format: :mod:<module-name>\n"
3484 " example: echo :mod:ext3 > set_ftrace_filter\n"
3485 " triggers: a command to perform when function is hit\n"
3486 " Format: <function>:<trigger>[:count]\n"
3487 " trigger: traceon, traceoff\n"
3488 " enable_event:<system>:<event>\n"
3489 " disable_event:<system>:<event>\n"
3490 #ifdef CONFIG_STACKTRACE
3493 #ifdef CONFIG_TRACER_SNAPSHOT
3496 " example: echo do_fault:traceoff > set_ftrace_filter\n"
3497 " echo do_trap:traceoff:3 > set_ftrace_filter\n"
3498 " The first one will disable tracing every time do_fault is hit\n"
3499 " The second will disable tracing at most 3 times when do_trap is hit\n"
3500 " The first time do trap is hit and it disables tracing, the counter\n"
3501 " will decrement to 2. If tracing is already disabled, the counter\n"
3502 " will not decrement. It only decrements when the trigger did work\n"
3503 " To remove trigger without count:\n"
3504 " echo '!<function>:<trigger> > set_ftrace_filter\n"
3505 " To remove trigger with a count:\n"
3506 " echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
3507 " set_ftrace_notrace\t- echo function name in here to never trace.\n"
3508 " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3509 " modules: Can select a group via module command :mod:\n"
3510 " Does not accept triggers\n"
3511 #endif /* CONFIG_DYNAMIC_FTRACE */
3512 #ifdef CONFIG_FUNCTION_TRACER
3513 " set_ftrace_pid\t- Write pid(s) to only function trace those pids (function)\n"
3515 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3516 " set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
3517 " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
3519 #ifdef CONFIG_TRACER_SNAPSHOT
3520 "\n snapshot\t\t- Like 'trace' but shows the content of the static snapshot buffer\n"
3521 "\t\t\t Read the contents for more information\n"
3523 #ifdef CONFIG_STACK_TRACER
3524 " stack_trace\t\t- Shows the max stack trace when active\n"
3525 " stack_max_size\t- Shows current max stack size that was traced\n"
3526 "\t\t\t Write into this file to reset the max size (trigger a new trace)\n"
3527 #ifdef CONFIG_DYNAMIC_FTRACE
3528 " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace traces\n"
3530 #endif /* CONFIG_STACK_TRACER */
3534 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
3535 size_t cnt
, loff_t
*ppos
)
3537 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
3538 readme_msg
, strlen(readme_msg
));
3541 static const struct file_operations tracing_readme_fops
= {
3542 .open
= tracing_open_generic
,
3543 .read
= tracing_readme_read
,
3544 .llseek
= generic_file_llseek
,
3548 tracing_saved_cmdlines_read(struct file
*file
, char __user
*ubuf
,
3549 size_t cnt
, loff_t
*ppos
)
3558 file_buf
= kmalloc(SAVED_CMDLINES
*(16+TASK_COMM_LEN
), GFP_KERNEL
);
3562 buf_comm
= kmalloc(TASK_COMM_LEN
, GFP_KERNEL
);
3570 for (i
= 0; i
< SAVED_CMDLINES
; i
++) {
3573 pid
= map_cmdline_to_pid
[i
];
3574 if (pid
== -1 || pid
== NO_CMDLINE_MAP
)
3577 trace_find_cmdline(pid
, buf_comm
);
3578 r
= sprintf(buf
, "%d %s\n", pid
, buf_comm
);
3583 len
= simple_read_from_buffer(ubuf
, cnt
, ppos
,
3592 static const struct file_operations tracing_saved_cmdlines_fops
= {
3593 .open
= tracing_open_generic
,
3594 .read
= tracing_saved_cmdlines_read
,
3595 .llseek
= generic_file_llseek
,
3599 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
3600 size_t cnt
, loff_t
*ppos
)
3602 struct trace_array
*tr
= filp
->private_data
;
3603 char buf
[MAX_TRACER_SIZE
+2];
3606 mutex_lock(&trace_types_lock
);
3607 r
= sprintf(buf
, "%s\n", tr
->current_trace
->name
);
3608 mutex_unlock(&trace_types_lock
);
3610 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3613 int tracer_init(struct tracer
*t
, struct trace_array
*tr
)
3615 tracing_reset_online_cpus(&tr
->trace_buffer
);
3619 static void set_buffer_entries(struct trace_buffer
*buf
, unsigned long val
)
3623 for_each_tracing_cpu(cpu
)
3624 per_cpu_ptr(buf
->data
, cpu
)->entries
= val
;
3627 #ifdef CONFIG_TRACER_MAX_TRACE
3628 /* resize @tr's buffer to the size of @size_tr's entries */
3629 static int resize_buffer_duplicate_size(struct trace_buffer
*trace_buf
,
3630 struct trace_buffer
*size_buf
, int cpu_id
)
3634 if (cpu_id
== RING_BUFFER_ALL_CPUS
) {
3635 for_each_tracing_cpu(cpu
) {
3636 ret
= ring_buffer_resize(trace_buf
->buffer
,
3637 per_cpu_ptr(size_buf
->data
, cpu
)->entries
, cpu
);
3640 per_cpu_ptr(trace_buf
->data
, cpu
)->entries
=
3641 per_cpu_ptr(size_buf
->data
, cpu
)->entries
;
3644 ret
= ring_buffer_resize(trace_buf
->buffer
,
3645 per_cpu_ptr(size_buf
->data
, cpu_id
)->entries
, cpu_id
);
3647 per_cpu_ptr(trace_buf
->data
, cpu_id
)->entries
=
3648 per_cpu_ptr(size_buf
->data
, cpu_id
)->entries
;
3653 #endif /* CONFIG_TRACER_MAX_TRACE */
3655 static int __tracing_resize_ring_buffer(struct trace_array
*tr
,
3656 unsigned long size
, int cpu
)
3661 * If kernel or user changes the size of the ring buffer
3662 * we use the size that was given, and we can forget about
3663 * expanding it later.
3665 ring_buffer_expanded
= true;
3667 /* May be called before buffers are initialized */
3668 if (!tr
->trace_buffer
.buffer
)
3671 ret
= ring_buffer_resize(tr
->trace_buffer
.buffer
, size
, cpu
);
3675 #ifdef CONFIG_TRACER_MAX_TRACE
3676 if (!(tr
->flags
& TRACE_ARRAY_FL_GLOBAL
) ||
3677 !tr
->current_trace
->use_max_tr
)
3680 ret
= ring_buffer_resize(tr
->max_buffer
.buffer
, size
, cpu
);
3682 int r
= resize_buffer_duplicate_size(&tr
->trace_buffer
,
3683 &tr
->trace_buffer
, cpu
);
3686 * AARGH! We are left with different
3687 * size max buffer!!!!
3688 * The max buffer is our "snapshot" buffer.
3689 * When a tracer needs a snapshot (one of the
3690 * latency tracers), it swaps the max buffer
3691 * with the saved snap shot. We succeeded to
3692 * update the size of the main buffer, but failed to
3693 * update the size of the max buffer. But when we tried
3694 * to reset the main buffer to the original size, we
3695 * failed there too. This is very unlikely to
3696 * happen, but if it does, warn and kill all
3700 tracing_disabled
= 1;
3705 if (cpu
== RING_BUFFER_ALL_CPUS
)
3706 set_buffer_entries(&tr
->max_buffer
, size
);
3708 per_cpu_ptr(tr
->max_buffer
.data
, cpu
)->entries
= size
;
3711 #endif /* CONFIG_TRACER_MAX_TRACE */
3713 if (cpu
== RING_BUFFER_ALL_CPUS
)
3714 set_buffer_entries(&tr
->trace_buffer
, size
);
3716 per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
= size
;
3721 static ssize_t
tracing_resize_ring_buffer(struct trace_array
*tr
,
3722 unsigned long size
, int cpu_id
)
3726 mutex_lock(&trace_types_lock
);
3728 if (cpu_id
!= RING_BUFFER_ALL_CPUS
) {
3729 /* make sure, this cpu is enabled in the mask */
3730 if (!cpumask_test_cpu(cpu_id
, tracing_buffer_mask
)) {
3736 ret
= __tracing_resize_ring_buffer(tr
, size
, cpu_id
);
3741 mutex_unlock(&trace_types_lock
);
3748 * tracing_update_buffers - used by tracing facility to expand ring buffers
3750 * To save on memory when the tracing is never used on a system with it
3751 * configured in. The ring buffers are set to a minimum size. But once
3752 * a user starts to use the tracing facility, then they need to grow
3753 * to their default size.
3755 * This function is to be called when a tracer is about to be used.
3757 int tracing_update_buffers(void)
3761 mutex_lock(&trace_types_lock
);
3762 if (!ring_buffer_expanded
)
3763 ret
= __tracing_resize_ring_buffer(&global_trace
, trace_buf_size
,
3764 RING_BUFFER_ALL_CPUS
);
3765 mutex_unlock(&trace_types_lock
);
3770 struct trace_option_dentry
;
3772 static struct trace_option_dentry
*
3773 create_trace_option_files(struct trace_array
*tr
, struct tracer
*tracer
);
3776 destroy_trace_option_files(struct trace_option_dentry
*topts
);
3778 static int tracing_set_tracer(const char *buf
)
3780 static struct trace_option_dentry
*topts
;
3781 struct trace_array
*tr
= &global_trace
;
3783 #ifdef CONFIG_TRACER_MAX_TRACE
3788 mutex_lock(&trace_types_lock
);
3790 if (!ring_buffer_expanded
) {
3791 ret
= __tracing_resize_ring_buffer(tr
, trace_buf_size
,
3792 RING_BUFFER_ALL_CPUS
);
3798 for (t
= trace_types
; t
; t
= t
->next
) {
3799 if (strcmp(t
->name
, buf
) == 0)
3806 if (t
== tr
->current_trace
)
3809 trace_branch_disable();
3811 tr
->current_trace
->enabled
= false;
3813 if (tr
->current_trace
->reset
)
3814 tr
->current_trace
->reset(tr
);
3816 /* Current trace needs to be nop_trace before synchronize_sched */
3817 tr
->current_trace
= &nop_trace
;
3819 #ifdef CONFIG_TRACER_MAX_TRACE
3820 had_max_tr
= tr
->allocated_snapshot
;
3822 if (had_max_tr
&& !t
->use_max_tr
) {
3824 * We need to make sure that the update_max_tr sees that
3825 * current_trace changed to nop_trace to keep it from
3826 * swapping the buffers after we resize it.
3827 * The update_max_tr is called from interrupts disabled
3828 * so a synchronized_sched() is sufficient.
3830 synchronize_sched();
3834 destroy_trace_option_files(topts
);
3836 topts
= create_trace_option_files(tr
, t
);
3838 #ifdef CONFIG_TRACER_MAX_TRACE
3839 if (t
->use_max_tr
&& !had_max_tr
) {
3840 ret
= alloc_snapshot(tr
);
3847 ret
= tracer_init(t
, tr
);
3852 tr
->current_trace
= t
;
3853 tr
->current_trace
->enabled
= true;
3854 trace_branch_enable(tr
);
3856 mutex_unlock(&trace_types_lock
);
3862 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
3863 size_t cnt
, loff_t
*ppos
)
3865 char buf
[MAX_TRACER_SIZE
+1];
3872 if (cnt
> MAX_TRACER_SIZE
)
3873 cnt
= MAX_TRACER_SIZE
;
3875 if (copy_from_user(&buf
, ubuf
, cnt
))
3880 /* strip ending whitespace. */
3881 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
3884 err
= tracing_set_tracer(buf
);
3894 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
3895 size_t cnt
, loff_t
*ppos
)
3897 unsigned long *ptr
= filp
->private_data
;
3901 r
= snprintf(buf
, sizeof(buf
), "%ld\n",
3902 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
3903 if (r
> sizeof(buf
))
3905 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3909 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
3910 size_t cnt
, loff_t
*ppos
)
3912 unsigned long *ptr
= filp
->private_data
;
3916 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
3925 static int tracing_open_pipe(struct inode
*inode
, struct file
*filp
)
3927 struct trace_array
*tr
= inode
->i_private
;
3928 struct trace_iterator
*iter
;
3931 if (tracing_disabled
)
3934 if (trace_array_get(tr
) < 0)
3937 mutex_lock(&trace_types_lock
);
3939 /* create a buffer to store the information to pass to userspace */
3940 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
3943 __trace_array_put(tr
);
3948 * We make a copy of the current tracer to avoid concurrent
3949 * changes on it while we are reading.
3951 iter
->trace
= kmalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
3956 *iter
->trace
= *tr
->current_trace
;
3958 if (!alloc_cpumask_var(&iter
->started
, GFP_KERNEL
)) {
3963 /* trace pipe does not show start of buffer */
3964 cpumask_setall(iter
->started
);
3966 if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
3967 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
3969 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
3970 if (trace_clocks
[tr
->clock_id
].in_ns
)
3971 iter
->iter_flags
|= TRACE_FILE_TIME_IN_NS
;
3974 iter
->trace_buffer
= &tr
->trace_buffer
;
3975 iter
->cpu_file
= tracing_get_cpu(inode
);
3976 mutex_init(&iter
->mutex
);
3977 filp
->private_data
= iter
;
3979 if (iter
->trace
->pipe_open
)
3980 iter
->trace
->pipe_open(iter
);
3982 nonseekable_open(inode
, filp
);
3984 mutex_unlock(&trace_types_lock
);
3990 __trace_array_put(tr
);
3991 mutex_unlock(&trace_types_lock
);
3995 static int tracing_release_pipe(struct inode
*inode
, struct file
*file
)
3997 struct trace_iterator
*iter
= file
->private_data
;
3998 struct trace_array
*tr
= inode
->i_private
;
4000 mutex_lock(&trace_types_lock
);
4002 if (iter
->trace
->pipe_close
)
4003 iter
->trace
->pipe_close(iter
);
4005 mutex_unlock(&trace_types_lock
);
4007 free_cpumask_var(iter
->started
);
4008 mutex_destroy(&iter
->mutex
);
4012 trace_array_put(tr
);
4018 trace_poll(struct trace_iterator
*iter
, struct file
*filp
, poll_table
*poll_table
)
4020 /* Iterators are static, they should be filled or empty */
4021 if (trace_buffer_iter(iter
, iter
->cpu_file
))
4022 return POLLIN
| POLLRDNORM
;
4024 if (trace_flags
& TRACE_ITER_BLOCK
)
4026 * Always select as readable when in blocking mode
4028 return POLLIN
| POLLRDNORM
;
4030 return ring_buffer_poll_wait(iter
->trace_buffer
->buffer
, iter
->cpu_file
,
4035 tracing_poll_pipe(struct file
*filp
, poll_table
*poll_table
)
4037 struct trace_iterator
*iter
= filp
->private_data
;
4039 return trace_poll(iter
, filp
, poll_table
);
4043 * This is a make-shift waitqueue.
4044 * A tracer might use this callback on some rare cases:
4046 * 1) the current tracer might hold the runqueue lock when it wakes up
4047 * a reader, hence a deadlock (sched, function, and function graph tracers)
4048 * 2) the function tracers, trace all functions, we don't want
4049 * the overhead of calling wake_up and friends
4050 * (and tracing them too)
4052 * Anyway, this is really very primitive wakeup.
4054 void poll_wait_pipe(struct trace_iterator
*iter
)
4056 set_current_state(TASK_INTERRUPTIBLE
);
4057 /* sleep for 100 msecs, and try again. */
4058 schedule_timeout(HZ
/ 10);
4061 /* Must be called with trace_types_lock mutex held. */
4062 static int tracing_wait_pipe(struct file
*filp
)
4064 struct trace_iterator
*iter
= filp
->private_data
;
4066 while (trace_empty(iter
)) {
4068 if ((filp
->f_flags
& O_NONBLOCK
)) {
4072 mutex_unlock(&iter
->mutex
);
4074 iter
->trace
->wait_pipe(iter
);
4076 mutex_lock(&iter
->mutex
);
4078 if (signal_pending(current
))
4082 * We block until we read something and tracing is disabled.
4083 * We still block if tracing is disabled, but we have never
4084 * read anything. This allows a user to cat this file, and
4085 * then enable tracing. But after we have read something,
4086 * we give an EOF when tracing is again disabled.
4088 * iter->pos will be 0 if we haven't read anything.
4090 if (!tracing_is_on() && iter
->pos
)
4101 tracing_read_pipe(struct file
*filp
, char __user
*ubuf
,
4102 size_t cnt
, loff_t
*ppos
)
4104 struct trace_iterator
*iter
= filp
->private_data
;
4105 struct trace_array
*tr
= iter
->tr
;
4108 /* return any leftover data */
4109 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
4113 trace_seq_init(&iter
->seq
);
4115 /* copy the tracer to avoid using a global lock all around */
4116 mutex_lock(&trace_types_lock
);
4117 if (unlikely(iter
->trace
->name
!= tr
->current_trace
->name
))
4118 *iter
->trace
= *tr
->current_trace
;
4119 mutex_unlock(&trace_types_lock
);
4122 * Avoid more than one consumer on a single file descriptor
4123 * This is just a matter of traces coherency, the ring buffer itself
4126 mutex_lock(&iter
->mutex
);
4127 if (iter
->trace
->read
) {
4128 sret
= iter
->trace
->read(iter
, filp
, ubuf
, cnt
, ppos
);
4134 sret
= tracing_wait_pipe(filp
);
4138 /* stop when tracing is finished */
4139 if (trace_empty(iter
)) {
4144 if (cnt
>= PAGE_SIZE
)
4145 cnt
= PAGE_SIZE
- 1;
4147 /* reset all but tr, trace, and overruns */
4148 memset(&iter
->seq
, 0,
4149 sizeof(struct trace_iterator
) -
4150 offsetof(struct trace_iterator
, seq
));
4151 cpumask_clear(iter
->started
);
4154 trace_event_read_lock();
4155 trace_access_lock(iter
->cpu_file
);
4156 while (trace_find_next_entry_inc(iter
) != NULL
) {
4157 enum print_line_t ret
;
4158 int len
= iter
->seq
.len
;
4160 ret
= print_trace_line(iter
);
4161 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
4162 /* don't print partial lines */
4163 iter
->seq
.len
= len
;
4166 if (ret
!= TRACE_TYPE_NO_CONSUME
)
4167 trace_consume(iter
);
4169 if (iter
->seq
.len
>= cnt
)
4173 * Setting the full flag means we reached the trace_seq buffer
4174 * size and we should leave by partial output condition above.
4175 * One of the trace_seq_* functions is not used properly.
4177 WARN_ONCE(iter
->seq
.full
, "full flag set for trace type %d",
4180 trace_access_unlock(iter
->cpu_file
);
4181 trace_event_read_unlock();
4183 /* Now copy what we have to the user */
4184 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
4185 if (iter
->seq
.readpos
>= iter
->seq
.len
)
4186 trace_seq_init(&iter
->seq
);
4189 * If there was nothing to send to user, in spite of consuming trace
4190 * entries, go back to wait for more entries.
4196 mutex_unlock(&iter
->mutex
);
4201 static void tracing_pipe_buf_release(struct pipe_inode_info
*pipe
,
4202 struct pipe_buffer
*buf
)
4204 __free_page(buf
->page
);
4207 static void tracing_spd_release_pipe(struct splice_pipe_desc
*spd
,
4210 __free_page(spd
->pages
[idx
]);
4213 static const struct pipe_buf_operations tracing_pipe_buf_ops
= {
4215 .map
= generic_pipe_buf_map
,
4216 .unmap
= generic_pipe_buf_unmap
,
4217 .confirm
= generic_pipe_buf_confirm
,
4218 .release
= tracing_pipe_buf_release
,
4219 .steal
= generic_pipe_buf_steal
,
4220 .get
= generic_pipe_buf_get
,
4224 tracing_fill_pipe_page(size_t rem
, struct trace_iterator
*iter
)
4229 /* Seq buffer is page-sized, exactly what we need. */
4231 count
= iter
->seq
.len
;
4232 ret
= print_trace_line(iter
);
4233 count
= iter
->seq
.len
- count
;
4236 iter
->seq
.len
-= count
;
4239 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
4240 iter
->seq
.len
-= count
;
4244 if (ret
!= TRACE_TYPE_NO_CONSUME
)
4245 trace_consume(iter
);
4247 if (!trace_find_next_entry_inc(iter
)) {
4257 static ssize_t
tracing_splice_read_pipe(struct file
*filp
,
4259 struct pipe_inode_info
*pipe
,
4263 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
4264 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
4265 struct trace_iterator
*iter
= filp
->private_data
;
4266 struct splice_pipe_desc spd
= {
4268 .partial
= partial_def
,
4269 .nr_pages
= 0, /* This gets updated below. */
4270 .nr_pages_max
= PIPE_DEF_BUFFERS
,
4272 .ops
= &tracing_pipe_buf_ops
,
4273 .spd_release
= tracing_spd_release_pipe
,
4275 struct trace_array
*tr
= iter
->tr
;
4280 if (splice_grow_spd(pipe
, &spd
))
4283 /* copy the tracer to avoid using a global lock all around */
4284 mutex_lock(&trace_types_lock
);
4285 if (unlikely(iter
->trace
->name
!= tr
->current_trace
->name
))
4286 *iter
->trace
= *tr
->current_trace
;
4287 mutex_unlock(&trace_types_lock
);
4289 mutex_lock(&iter
->mutex
);
4291 if (iter
->trace
->splice_read
) {
4292 ret
= iter
->trace
->splice_read(iter
, filp
,
4293 ppos
, pipe
, len
, flags
);
4298 ret
= tracing_wait_pipe(filp
);
4302 if (!iter
->ent
&& !trace_find_next_entry_inc(iter
)) {
4307 trace_event_read_lock();
4308 trace_access_lock(iter
->cpu_file
);
4310 /* Fill as many pages as possible. */
4311 for (i
= 0, rem
= len
; i
< pipe
->buffers
&& rem
; i
++) {
4312 spd
.pages
[i
] = alloc_page(GFP_KERNEL
);
4316 rem
= tracing_fill_pipe_page(rem
, iter
);
4318 /* Copy the data into the page, so we can start over. */
4319 ret
= trace_seq_to_buffer(&iter
->seq
,
4320 page_address(spd
.pages
[i
]),
4323 __free_page(spd
.pages
[i
]);
4326 spd
.partial
[i
].offset
= 0;
4327 spd
.partial
[i
].len
= iter
->seq
.len
;
4329 trace_seq_init(&iter
->seq
);
4332 trace_access_unlock(iter
->cpu_file
);
4333 trace_event_read_unlock();
4334 mutex_unlock(&iter
->mutex
);
4338 ret
= splice_to_pipe(pipe
, &spd
);
4340 splice_shrink_spd(&spd
);
4344 mutex_unlock(&iter
->mutex
);
4349 tracing_entries_read(struct file
*filp
, char __user
*ubuf
,
4350 size_t cnt
, loff_t
*ppos
)
4352 struct inode
*inode
= file_inode(filp
);
4353 struct trace_array
*tr
= inode
->i_private
;
4354 int cpu
= tracing_get_cpu(inode
);
4359 mutex_lock(&trace_types_lock
);
4361 if (cpu
== RING_BUFFER_ALL_CPUS
) {
4362 int cpu
, buf_size_same
;
4367 /* check if all cpu sizes are same */
4368 for_each_tracing_cpu(cpu
) {
4369 /* fill in the size from first enabled cpu */
4371 size
= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
;
4372 if (size
!= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
) {
4378 if (buf_size_same
) {
4379 if (!ring_buffer_expanded
)
4380 r
= sprintf(buf
, "%lu (expanded: %lu)\n",
4382 trace_buf_size
>> 10);
4384 r
= sprintf(buf
, "%lu\n", size
>> 10);
4386 r
= sprintf(buf
, "X\n");
4388 r
= sprintf(buf
, "%lu\n", per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
>> 10);
4390 mutex_unlock(&trace_types_lock
);
4392 ret
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
4397 tracing_entries_write(struct file
*filp
, const char __user
*ubuf
,
4398 size_t cnt
, loff_t
*ppos
)
4400 struct inode
*inode
= file_inode(filp
);
4401 struct trace_array
*tr
= inode
->i_private
;
4405 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
4409 /* must have at least 1 entry */
4413 /* value is in KB */
4415 ret
= tracing_resize_ring_buffer(tr
, val
, tracing_get_cpu(inode
));
4425 tracing_total_entries_read(struct file
*filp
, char __user
*ubuf
,
4426 size_t cnt
, loff_t
*ppos
)
4428 struct trace_array
*tr
= filp
->private_data
;
4431 unsigned long size
= 0, expanded_size
= 0;
4433 mutex_lock(&trace_types_lock
);
4434 for_each_tracing_cpu(cpu
) {
4435 size
+= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
>> 10;
4436 if (!ring_buffer_expanded
)
4437 expanded_size
+= trace_buf_size
>> 10;
4439 if (ring_buffer_expanded
)
4440 r
= sprintf(buf
, "%lu\n", size
);
4442 r
= sprintf(buf
, "%lu (expanded: %lu)\n", size
, expanded_size
);
4443 mutex_unlock(&trace_types_lock
);
4445 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
4449 tracing_free_buffer_write(struct file
*filp
, const char __user
*ubuf
,
4450 size_t cnt
, loff_t
*ppos
)
4453 * There is no need to read what the user has written, this function
4454 * is just to make sure that there is no error when "echo" is used
4463 tracing_free_buffer_release(struct inode
*inode
, struct file
*filp
)
4465 struct trace_array
*tr
= inode
->i_private
;
4467 /* disable tracing ? */
4468 if (trace_flags
& TRACE_ITER_STOP_ON_FREE
)
4469 tracer_tracing_off(tr
);
4470 /* resize the ring buffer to 0 */
4471 tracing_resize_ring_buffer(tr
, 0, RING_BUFFER_ALL_CPUS
);
4473 trace_array_put(tr
);
4479 tracing_mark_write(struct file
*filp
, const char __user
*ubuf
,
4480 size_t cnt
, loff_t
*fpos
)
4482 unsigned long addr
= (unsigned long)ubuf
;
4483 struct trace_array
*tr
= filp
->private_data
;
4484 struct ring_buffer_event
*event
;
4485 struct ring_buffer
*buffer
;
4486 struct print_entry
*entry
;
4487 unsigned long irq_flags
;
4488 struct page
*pages
[2];
4498 if (tracing_disabled
)
4501 if (!(trace_flags
& TRACE_ITER_MARKERS
))
4504 if (cnt
> TRACE_BUF_SIZE
)
4505 cnt
= TRACE_BUF_SIZE
;
4508 * Userspace is injecting traces into the kernel trace buffer.
4509 * We want to be as non intrusive as possible.
4510 * To do so, we do not want to allocate any special buffers
4511 * or take any locks, but instead write the userspace data
4512 * straight into the ring buffer.
4514 * First we need to pin the userspace buffer into memory,
4515 * which, most likely it is, because it just referenced it.
4516 * But there's no guarantee that it is. By using get_user_pages_fast()
4517 * and kmap_atomic/kunmap_atomic() we can get access to the
4518 * pages directly. We then write the data directly into the
4521 BUILD_BUG_ON(TRACE_BUF_SIZE
>= PAGE_SIZE
);
4523 /* check if we cross pages */
4524 if ((addr
& PAGE_MASK
) != ((addr
+ cnt
) & PAGE_MASK
))
4527 offset
= addr
& (PAGE_SIZE
- 1);
4530 ret
= get_user_pages_fast(addr
, nr_pages
, 0, pages
);
4531 if (ret
< nr_pages
) {
4533 put_page(pages
[ret
]);
4538 for (i
= 0; i
< nr_pages
; i
++)
4539 map_page
[i
] = kmap_atomic(pages
[i
]);
4541 local_save_flags(irq_flags
);
4542 size
= sizeof(*entry
) + cnt
+ 2; /* possible \n added */
4543 buffer
= tr
->trace_buffer
.buffer
;
4544 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, size
,
4545 irq_flags
, preempt_count());
4547 /* Ring buffer disabled, return as if not open for write */
4552 entry
= ring_buffer_event_data(event
);
4553 entry
->ip
= _THIS_IP_
;
4555 if (nr_pages
== 2) {
4556 len
= PAGE_SIZE
- offset
;
4557 memcpy(&entry
->buf
, map_page
[0] + offset
, len
);
4558 memcpy(&entry
->buf
[len
], map_page
[1], cnt
- len
);
4560 memcpy(&entry
->buf
, map_page
[0] + offset
, cnt
);
4562 if (entry
->buf
[cnt
- 1] != '\n') {
4563 entry
->buf
[cnt
] = '\n';
4564 entry
->buf
[cnt
+ 1] = '\0';
4566 entry
->buf
[cnt
] = '\0';
4568 __buffer_unlock_commit(buffer
, event
);
4575 for (i
= 0; i
< nr_pages
; i
++){
4576 kunmap_atomic(map_page
[i
]);
4583 static int tracing_clock_show(struct seq_file
*m
, void *v
)
4585 struct trace_array
*tr
= m
->private;
4588 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++)
4590 "%s%s%s%s", i
? " " : "",
4591 i
== tr
->clock_id
? "[" : "", trace_clocks
[i
].name
,
4592 i
== tr
->clock_id
? "]" : "");
4598 static ssize_t
tracing_clock_write(struct file
*filp
, const char __user
*ubuf
,
4599 size_t cnt
, loff_t
*fpos
)
4601 struct seq_file
*m
= filp
->private_data
;
4602 struct trace_array
*tr
= m
->private;
4604 const char *clockstr
;
4607 if (cnt
>= sizeof(buf
))
4610 if (copy_from_user(&buf
, ubuf
, cnt
))
4615 clockstr
= strstrip(buf
);
4617 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++) {
4618 if (strcmp(trace_clocks
[i
].name
, clockstr
) == 0)
4621 if (i
== ARRAY_SIZE(trace_clocks
))
4624 mutex_lock(&trace_types_lock
);
4628 ring_buffer_set_clock(tr
->trace_buffer
.buffer
, trace_clocks
[i
].func
);
4631 * New clock may not be consistent with the previous clock.
4632 * Reset the buffer so that it doesn't have incomparable timestamps.
4634 tracing_reset_online_cpus(&tr
->trace_buffer
);
4636 #ifdef CONFIG_TRACER_MAX_TRACE
4637 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
&& tr
->max_buffer
.buffer
)
4638 ring_buffer_set_clock(tr
->max_buffer
.buffer
, trace_clocks
[i
].func
);
4639 tracing_reset_online_cpus(&tr
->max_buffer
);
4642 mutex_unlock(&trace_types_lock
);
4649 static int tracing_clock_open(struct inode
*inode
, struct file
*file
)
4651 struct trace_array
*tr
= inode
->i_private
;
4654 if (tracing_disabled
)
4657 if (trace_array_get(tr
))
4660 ret
= single_open(file
, tracing_clock_show
, inode
->i_private
);
4662 trace_array_put(tr
);
4667 struct ftrace_buffer_info
{
4668 struct trace_iterator iter
;
4673 #ifdef CONFIG_TRACER_SNAPSHOT
4674 static int tracing_snapshot_open(struct inode
*inode
, struct file
*file
)
4676 struct trace_array
*tr
= inode
->i_private
;
4677 struct trace_iterator
*iter
;
4681 if (trace_array_get(tr
) < 0)
4684 if (file
->f_mode
& FMODE_READ
) {
4685 iter
= __tracing_open(inode
, file
, true);
4687 ret
= PTR_ERR(iter
);
4689 /* Writes still need the seq_file to hold the private data */
4691 m
= kzalloc(sizeof(*m
), GFP_KERNEL
);
4694 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
4702 iter
->trace_buffer
= &tr
->max_buffer
;
4703 iter
->cpu_file
= tracing_get_cpu(inode
);
4705 file
->private_data
= m
;
4709 trace_array_put(tr
);
4715 tracing_snapshot_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
4718 struct seq_file
*m
= filp
->private_data
;
4719 struct trace_iterator
*iter
= m
->private;
4720 struct trace_array
*tr
= iter
->tr
;
4724 ret
= tracing_update_buffers();
4728 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
4732 mutex_lock(&trace_types_lock
);
4734 if (tr
->current_trace
->use_max_tr
) {
4741 if (iter
->cpu_file
!= RING_BUFFER_ALL_CPUS
) {
4745 if (tr
->allocated_snapshot
)
4749 /* Only allow per-cpu swap if the ring buffer supports it */
4750 #ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
4751 if (iter
->cpu_file
!= RING_BUFFER_ALL_CPUS
) {
4756 if (!tr
->allocated_snapshot
) {
4757 ret
= alloc_snapshot(tr
);
4761 local_irq_disable();
4762 /* Now, we're going to swap */
4763 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
)
4764 update_max_tr(tr
, current
, smp_processor_id());
4766 update_max_tr_single(tr
, current
, iter
->cpu_file
);
4770 if (tr
->allocated_snapshot
) {
4771 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
)
4772 tracing_reset_online_cpus(&tr
->max_buffer
);
4774 tracing_reset(&tr
->max_buffer
, iter
->cpu_file
);
4784 mutex_unlock(&trace_types_lock
);
4788 static int tracing_snapshot_release(struct inode
*inode
, struct file
*file
)
4790 struct seq_file
*m
= file
->private_data
;
4793 ret
= tracing_release(inode
, file
);
4795 if (file
->f_mode
& FMODE_READ
)
4798 /* If write only, the seq_file is just a stub */
4806 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
);
4807 static ssize_t
tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
4808 size_t count
, loff_t
*ppos
);
4809 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
);
4810 static ssize_t
tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
4811 struct pipe_inode_info
*pipe
, size_t len
, unsigned int flags
);
4813 static int snapshot_raw_open(struct inode
*inode
, struct file
*filp
)
4815 struct ftrace_buffer_info
*info
;
4818 ret
= tracing_buffers_open(inode
, filp
);
4822 info
= filp
->private_data
;
4824 if (info
->iter
.trace
->use_max_tr
) {
4825 tracing_buffers_release(inode
, filp
);
4829 info
->iter
.snapshot
= true;
4830 info
->iter
.trace_buffer
= &info
->iter
.tr
->max_buffer
;
4835 #endif /* CONFIG_TRACER_SNAPSHOT */
4838 static const struct file_operations tracing_max_lat_fops
= {
4839 .open
= tracing_open_generic
,
4840 .read
= tracing_max_lat_read
,
4841 .write
= tracing_max_lat_write
,
4842 .llseek
= generic_file_llseek
,
4845 static const struct file_operations set_tracer_fops
= {
4846 .open
= tracing_open_generic
,
4847 .read
= tracing_set_trace_read
,
4848 .write
= tracing_set_trace_write
,
4849 .llseek
= generic_file_llseek
,
4852 static const struct file_operations tracing_pipe_fops
= {
4853 .open
= tracing_open_pipe
,
4854 .poll
= tracing_poll_pipe
,
4855 .read
= tracing_read_pipe
,
4856 .splice_read
= tracing_splice_read_pipe
,
4857 .release
= tracing_release_pipe
,
4858 .llseek
= no_llseek
,
4861 static const struct file_operations tracing_entries_fops
= {
4862 .open
= tracing_open_generic_tr
,
4863 .read
= tracing_entries_read
,
4864 .write
= tracing_entries_write
,
4865 .llseek
= generic_file_llseek
,
4866 .release
= tracing_release_generic_tr
,
4869 static const struct file_operations tracing_total_entries_fops
= {
4870 .open
= tracing_open_generic_tr
,
4871 .read
= tracing_total_entries_read
,
4872 .llseek
= generic_file_llseek
,
4873 .release
= tracing_release_generic_tr
,
4876 static const struct file_operations tracing_free_buffer_fops
= {
4877 .open
= tracing_open_generic_tr
,
4878 .write
= tracing_free_buffer_write
,
4879 .release
= tracing_free_buffer_release
,
4882 static const struct file_operations tracing_mark_fops
= {
4883 .open
= tracing_open_generic_tr
,
4884 .write
= tracing_mark_write
,
4885 .llseek
= generic_file_llseek
,
4886 .release
= tracing_release_generic_tr
,
4889 static const struct file_operations trace_clock_fops
= {
4890 .open
= tracing_clock_open
,
4892 .llseek
= seq_lseek
,
4893 .release
= tracing_single_release_tr
,
4894 .write
= tracing_clock_write
,
4897 #ifdef CONFIG_TRACER_SNAPSHOT
4898 static const struct file_operations snapshot_fops
= {
4899 .open
= tracing_snapshot_open
,
4901 .write
= tracing_snapshot_write
,
4902 .llseek
= tracing_seek
,
4903 .release
= tracing_snapshot_release
,
4906 static const struct file_operations snapshot_raw_fops
= {
4907 .open
= snapshot_raw_open
,
4908 .read
= tracing_buffers_read
,
4909 .release
= tracing_buffers_release
,
4910 .splice_read
= tracing_buffers_splice_read
,
4911 .llseek
= no_llseek
,
4914 #endif /* CONFIG_TRACER_SNAPSHOT */
4916 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
)
4918 struct trace_array
*tr
= inode
->i_private
;
4919 struct ftrace_buffer_info
*info
;
4922 if (tracing_disabled
)
4925 if (trace_array_get(tr
) < 0)
4928 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
4930 trace_array_put(tr
);
4934 mutex_lock(&trace_types_lock
);
4937 info
->iter
.cpu_file
= tracing_get_cpu(inode
);
4938 info
->iter
.trace
= tr
->current_trace
;
4939 info
->iter
.trace_buffer
= &tr
->trace_buffer
;
4941 /* Force reading ring buffer for first read */
4942 info
->read
= (unsigned int)-1;
4944 filp
->private_data
= info
;
4946 mutex_unlock(&trace_types_lock
);
4948 ret
= nonseekable_open(inode
, filp
);
4950 trace_array_put(tr
);
4956 tracing_buffers_poll(struct file
*filp
, poll_table
*poll_table
)
4958 struct ftrace_buffer_info
*info
= filp
->private_data
;
4959 struct trace_iterator
*iter
= &info
->iter
;
4961 return trace_poll(iter
, filp
, poll_table
);
4965 tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
4966 size_t count
, loff_t
*ppos
)
4968 struct ftrace_buffer_info
*info
= filp
->private_data
;
4969 struct trace_iterator
*iter
= &info
->iter
;
4976 mutex_lock(&trace_types_lock
);
4978 #ifdef CONFIG_TRACER_MAX_TRACE
4979 if (iter
->snapshot
&& iter
->tr
->current_trace
->use_max_tr
) {
4986 info
->spare
= ring_buffer_alloc_read_page(iter
->trace_buffer
->buffer
,
4992 /* Do we have previous read data to read? */
4993 if (info
->read
< PAGE_SIZE
)
4997 trace_access_lock(iter
->cpu_file
);
4998 ret
= ring_buffer_read_page(iter
->trace_buffer
->buffer
,
5002 trace_access_unlock(iter
->cpu_file
);
5005 if (trace_empty(iter
)) {
5006 if ((filp
->f_flags
& O_NONBLOCK
)) {
5010 mutex_unlock(&trace_types_lock
);
5011 iter
->trace
->wait_pipe(iter
);
5012 mutex_lock(&trace_types_lock
);
5013 if (signal_pending(current
)) {
5025 size
= PAGE_SIZE
- info
->read
;
5029 ret
= copy_to_user(ubuf
, info
->spare
+ info
->read
, size
);
5040 mutex_unlock(&trace_types_lock
);
5045 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
)
5047 struct ftrace_buffer_info
*info
= file
->private_data
;
5048 struct trace_iterator
*iter
= &info
->iter
;
5050 mutex_lock(&trace_types_lock
);
5052 __trace_array_put(iter
->tr
);
5055 ring_buffer_free_read_page(iter
->trace_buffer
->buffer
, info
->spare
);
5058 mutex_unlock(&trace_types_lock
);
5064 struct ring_buffer
*buffer
;
5069 static void buffer_pipe_buf_release(struct pipe_inode_info
*pipe
,
5070 struct pipe_buffer
*buf
)
5072 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
5077 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
5082 static void buffer_pipe_buf_get(struct pipe_inode_info
*pipe
,
5083 struct pipe_buffer
*buf
)
5085 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
5090 /* Pipe buffer operations for a buffer. */
5091 static const struct pipe_buf_operations buffer_pipe_buf_ops
= {
5093 .map
= generic_pipe_buf_map
,
5094 .unmap
= generic_pipe_buf_unmap
,
5095 .confirm
= generic_pipe_buf_confirm
,
5096 .release
= buffer_pipe_buf_release
,
5097 .steal
= generic_pipe_buf_steal
,
5098 .get
= buffer_pipe_buf_get
,
5102 * Callback from splice_to_pipe(), if we need to release some pages
5103 * at the end of the spd in case we error'ed out in filling the pipe.
5105 static void buffer_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
5107 struct buffer_ref
*ref
=
5108 (struct buffer_ref
*)spd
->partial
[i
].private;
5113 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
5115 spd
->partial
[i
].private = 0;
5119 tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
5120 struct pipe_inode_info
*pipe
, size_t len
,
5123 struct ftrace_buffer_info
*info
= file
->private_data
;
5124 struct trace_iterator
*iter
= &info
->iter
;
5125 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
5126 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
5127 struct splice_pipe_desc spd
= {
5129 .partial
= partial_def
,
5130 .nr_pages_max
= PIPE_DEF_BUFFERS
,
5132 .ops
= &buffer_pipe_buf_ops
,
5133 .spd_release
= buffer_spd_release
,
5135 struct buffer_ref
*ref
;
5136 int entries
, size
, i
;
5139 mutex_lock(&trace_types_lock
);
5141 #ifdef CONFIG_TRACER_MAX_TRACE
5142 if (iter
->snapshot
&& iter
->tr
->current_trace
->use_max_tr
) {
5148 if (splice_grow_spd(pipe
, &spd
)) {
5153 if (*ppos
& (PAGE_SIZE
- 1)) {
5158 if (len
& (PAGE_SIZE
- 1)) {
5159 if (len
< PAGE_SIZE
) {
5167 trace_access_lock(iter
->cpu_file
);
5168 entries
= ring_buffer_entries_cpu(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
5170 for (i
= 0; i
< pipe
->buffers
&& len
&& entries
; i
++, len
-= PAGE_SIZE
) {
5174 ref
= kzalloc(sizeof(*ref
), GFP_KERNEL
);
5179 ref
->buffer
= iter
->trace_buffer
->buffer
;
5180 ref
->page
= ring_buffer_alloc_read_page(ref
->buffer
, iter
->cpu_file
);
5186 r
= ring_buffer_read_page(ref
->buffer
, &ref
->page
,
5187 len
, iter
->cpu_file
, 1);
5189 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
5195 * zero out any left over data, this is going to
5198 size
= ring_buffer_page_len(ref
->page
);
5199 if (size
< PAGE_SIZE
)
5200 memset(ref
->page
+ size
, 0, PAGE_SIZE
- size
);
5202 page
= virt_to_page(ref
->page
);
5204 spd
.pages
[i
] = page
;
5205 spd
.partial
[i
].len
= PAGE_SIZE
;
5206 spd
.partial
[i
].offset
= 0;
5207 spd
.partial
[i
].private = (unsigned long)ref
;
5211 entries
= ring_buffer_entries_cpu(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
5214 trace_access_unlock(iter
->cpu_file
);
5217 /* did we read anything? */
5218 if (!spd
.nr_pages
) {
5219 if ((file
->f_flags
& O_NONBLOCK
) || (flags
& SPLICE_F_NONBLOCK
)) {
5223 mutex_unlock(&trace_types_lock
);
5224 iter
->trace
->wait_pipe(iter
);
5225 mutex_lock(&trace_types_lock
);
5226 if (signal_pending(current
)) {
5233 ret
= splice_to_pipe(pipe
, &spd
);
5234 splice_shrink_spd(&spd
);
5236 mutex_unlock(&trace_types_lock
);
5241 static const struct file_operations tracing_buffers_fops
= {
5242 .open
= tracing_buffers_open
,
5243 .read
= tracing_buffers_read
,
5244 .poll
= tracing_buffers_poll
,
5245 .release
= tracing_buffers_release
,
5246 .splice_read
= tracing_buffers_splice_read
,
5247 .llseek
= no_llseek
,
5251 tracing_stats_read(struct file
*filp
, char __user
*ubuf
,
5252 size_t count
, loff_t
*ppos
)
5254 struct inode
*inode
= file_inode(filp
);
5255 struct trace_array
*tr
= inode
->i_private
;
5256 struct trace_buffer
*trace_buf
= &tr
->trace_buffer
;
5257 int cpu
= tracing_get_cpu(inode
);
5258 struct trace_seq
*s
;
5260 unsigned long long t
;
5261 unsigned long usec_rem
;
5263 s
= kmalloc(sizeof(*s
), GFP_KERNEL
);
5269 cnt
= ring_buffer_entries_cpu(trace_buf
->buffer
, cpu
);
5270 trace_seq_printf(s
, "entries: %ld\n", cnt
);
5272 cnt
= ring_buffer_overrun_cpu(trace_buf
->buffer
, cpu
);
5273 trace_seq_printf(s
, "overrun: %ld\n", cnt
);
5275 cnt
= ring_buffer_commit_overrun_cpu(trace_buf
->buffer
, cpu
);
5276 trace_seq_printf(s
, "commit overrun: %ld\n", cnt
);
5278 cnt
= ring_buffer_bytes_cpu(trace_buf
->buffer
, cpu
);
5279 trace_seq_printf(s
, "bytes: %ld\n", cnt
);
5281 if (trace_clocks
[tr
->clock_id
].in_ns
) {
5282 /* local or global for trace_clock */
5283 t
= ns2usecs(ring_buffer_oldest_event_ts(trace_buf
->buffer
, cpu
));
5284 usec_rem
= do_div(t
, USEC_PER_SEC
);
5285 trace_seq_printf(s
, "oldest event ts: %5llu.%06lu\n",
5288 t
= ns2usecs(ring_buffer_time_stamp(trace_buf
->buffer
, cpu
));
5289 usec_rem
= do_div(t
, USEC_PER_SEC
);
5290 trace_seq_printf(s
, "now ts: %5llu.%06lu\n", t
, usec_rem
);
5292 /* counter or tsc mode for trace_clock */
5293 trace_seq_printf(s
, "oldest event ts: %llu\n",
5294 ring_buffer_oldest_event_ts(trace_buf
->buffer
, cpu
));
5296 trace_seq_printf(s
, "now ts: %llu\n",
5297 ring_buffer_time_stamp(trace_buf
->buffer
, cpu
));
5300 cnt
= ring_buffer_dropped_events_cpu(trace_buf
->buffer
, cpu
);
5301 trace_seq_printf(s
, "dropped events: %ld\n", cnt
);
5303 cnt
= ring_buffer_read_events_cpu(trace_buf
->buffer
, cpu
);
5304 trace_seq_printf(s
, "read events: %ld\n", cnt
);
5306 count
= simple_read_from_buffer(ubuf
, count
, ppos
, s
->buffer
, s
->len
);
5313 static const struct file_operations tracing_stats_fops
= {
5314 .open
= tracing_open_generic_tr
,
5315 .read
= tracing_stats_read
,
5316 .llseek
= generic_file_llseek
,
5317 .release
= tracing_release_generic_tr
,
5320 #ifdef CONFIG_DYNAMIC_FTRACE
5322 int __weak
ftrace_arch_read_dyn_info(char *buf
, int size
)
5328 tracing_read_dyn_info(struct file
*filp
, char __user
*ubuf
,
5329 size_t cnt
, loff_t
*ppos
)
5331 static char ftrace_dyn_info_buffer
[1024];
5332 static DEFINE_MUTEX(dyn_info_mutex
);
5333 unsigned long *p
= filp
->private_data
;
5334 char *buf
= ftrace_dyn_info_buffer
;
5335 int size
= ARRAY_SIZE(ftrace_dyn_info_buffer
);
5338 mutex_lock(&dyn_info_mutex
);
5339 r
= sprintf(buf
, "%ld ", *p
);
5341 r
+= ftrace_arch_read_dyn_info(buf
+r
, (size
-1)-r
);
5344 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
5346 mutex_unlock(&dyn_info_mutex
);
5351 static const struct file_operations tracing_dyn_info_fops
= {
5352 .open
= tracing_open_generic
,
5353 .read
= tracing_read_dyn_info
,
5354 .llseek
= generic_file_llseek
,
5356 #endif /* CONFIG_DYNAMIC_FTRACE */
5358 #if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
5360 ftrace_snapshot(unsigned long ip
, unsigned long parent_ip
, void **data
)
5366 ftrace_count_snapshot(unsigned long ip
, unsigned long parent_ip
, void **data
)
5368 unsigned long *count
= (long *)data
;
5380 ftrace_snapshot_print(struct seq_file
*m
, unsigned long ip
,
5381 struct ftrace_probe_ops
*ops
, void *data
)
5383 long count
= (long)data
;
5385 seq_printf(m
, "%ps:", (void *)ip
);
5387 seq_printf(m
, "snapshot");
5390 seq_printf(m
, ":unlimited\n");
5392 seq_printf(m
, ":count=%ld\n", count
);
5397 static struct ftrace_probe_ops snapshot_probe_ops
= {
5398 .func
= ftrace_snapshot
,
5399 .print
= ftrace_snapshot_print
,
5402 static struct ftrace_probe_ops snapshot_count_probe_ops
= {
5403 .func
= ftrace_count_snapshot
,
5404 .print
= ftrace_snapshot_print
,
5408 ftrace_trace_snapshot_callback(struct ftrace_hash
*hash
,
5409 char *glob
, char *cmd
, char *param
, int enable
)
5411 struct ftrace_probe_ops
*ops
;
5412 void *count
= (void *)-1;
5416 /* hash funcs only work with set_ftrace_filter */
5420 ops
= param
? &snapshot_count_probe_ops
: &snapshot_probe_ops
;
5422 if (glob
[0] == '!') {
5423 unregister_ftrace_function_probe_func(glob
+1, ops
);
5430 number
= strsep(¶m
, ":");
5432 if (!strlen(number
))
5436 * We use the callback data field (which is a pointer)
5439 ret
= kstrtoul(number
, 0, (unsigned long *)&count
);
5444 ret
= register_ftrace_function_probe(glob
, ops
, count
);
5447 alloc_snapshot(&global_trace
);
5449 return ret
< 0 ? ret
: 0;
5452 static struct ftrace_func_command ftrace_snapshot_cmd
= {
5454 .func
= ftrace_trace_snapshot_callback
,
5457 static int register_snapshot_cmd(void)
5459 return register_ftrace_command(&ftrace_snapshot_cmd
);
5462 static inline int register_snapshot_cmd(void) { return 0; }
5463 #endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
5465 struct dentry
*tracing_init_dentry_tr(struct trace_array
*tr
)
5470 if (!debugfs_initialized())
5473 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
5474 tr
->dir
= debugfs_create_dir("tracing", NULL
);
5477 pr_warn_once("Could not create debugfs directory 'tracing'\n");
5482 struct dentry
*tracing_init_dentry(void)
5484 return tracing_init_dentry_tr(&global_trace
);
5487 static struct dentry
*tracing_dentry_percpu(struct trace_array
*tr
, int cpu
)
5489 struct dentry
*d_tracer
;
5492 return tr
->percpu_dir
;
5494 d_tracer
= tracing_init_dentry_tr(tr
);
5498 tr
->percpu_dir
= debugfs_create_dir("per_cpu", d_tracer
);
5500 WARN_ONCE(!tr
->percpu_dir
,
5501 "Could not create debugfs directory 'per_cpu/%d'\n", cpu
);
5503 return tr
->percpu_dir
;
5506 static struct dentry
*
5507 trace_create_cpu_file(const char *name
, umode_t mode
, struct dentry
*parent
,
5508 void *data
, long cpu
, const struct file_operations
*fops
)
5510 struct dentry
*ret
= trace_create_file(name
, mode
, parent
, data
, fops
);
5512 if (ret
) /* See tracing_get_cpu() */
5513 ret
->d_inode
->i_cdev
= (void *)(cpu
+ 1);
5518 tracing_init_debugfs_percpu(struct trace_array
*tr
, long cpu
)
5520 struct dentry
*d_percpu
= tracing_dentry_percpu(tr
, cpu
);
5521 struct dentry
*d_cpu
;
5522 char cpu_dir
[30]; /* 30 characters should be more than enough */
5527 snprintf(cpu_dir
, 30, "cpu%ld", cpu
);
5528 d_cpu
= debugfs_create_dir(cpu_dir
, d_percpu
);
5530 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir
);
5534 /* per cpu trace_pipe */
5535 trace_create_cpu_file("trace_pipe", 0444, d_cpu
,
5536 tr
, cpu
, &tracing_pipe_fops
);
5539 trace_create_cpu_file("trace", 0644, d_cpu
,
5540 tr
, cpu
, &tracing_fops
);
5542 trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu
,
5543 tr
, cpu
, &tracing_buffers_fops
);
5545 trace_create_cpu_file("stats", 0444, d_cpu
,
5546 tr
, cpu
, &tracing_stats_fops
);
5548 trace_create_cpu_file("buffer_size_kb", 0444, d_cpu
,
5549 tr
, cpu
, &tracing_entries_fops
);
5551 #ifdef CONFIG_TRACER_SNAPSHOT
5552 trace_create_cpu_file("snapshot", 0644, d_cpu
,
5553 tr
, cpu
, &snapshot_fops
);
5555 trace_create_cpu_file("snapshot_raw", 0444, d_cpu
,
5556 tr
, cpu
, &snapshot_raw_fops
);
5560 #ifdef CONFIG_FTRACE_SELFTEST
5561 /* Let selftest have access to static functions in this file */
5562 #include "trace_selftest.c"
5565 struct trace_option_dentry
{
5566 struct tracer_opt
*opt
;
5567 struct tracer_flags
*flags
;
5568 struct trace_array
*tr
;
5569 struct dentry
*entry
;
5573 trace_options_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
5576 struct trace_option_dentry
*topt
= filp
->private_data
;
5579 if (topt
->flags
->val
& topt
->opt
->bit
)
5584 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
5588 trace_options_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
5591 struct trace_option_dentry
*topt
= filp
->private_data
;
5595 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5599 if (val
!= 0 && val
!= 1)
5602 if (!!(topt
->flags
->val
& topt
->opt
->bit
) != val
) {
5603 mutex_lock(&trace_types_lock
);
5604 ret
= __set_tracer_option(topt
->tr
->current_trace
, topt
->flags
,
5606 mutex_unlock(&trace_types_lock
);
5617 static const struct file_operations trace_options_fops
= {
5618 .open
= tracing_open_generic
,
5619 .read
= trace_options_read
,
5620 .write
= trace_options_write
,
5621 .llseek
= generic_file_llseek
,
5625 trace_options_core_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
5628 long index
= (long)filp
->private_data
;
5631 if (trace_flags
& (1 << index
))
5636 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
5640 trace_options_core_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
5643 struct trace_array
*tr
= &global_trace
;
5644 long index
= (long)filp
->private_data
;
5648 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5652 if (val
!= 0 && val
!= 1)
5655 mutex_lock(&trace_types_lock
);
5656 ret
= set_tracer_flag(tr
, 1 << index
, val
);
5657 mutex_unlock(&trace_types_lock
);
5667 static const struct file_operations trace_options_core_fops
= {
5668 .open
= tracing_open_generic
,
5669 .read
= trace_options_core_read
,
5670 .write
= trace_options_core_write
,
5671 .llseek
= generic_file_llseek
,
5674 struct dentry
*trace_create_file(const char *name
,
5676 struct dentry
*parent
,
5678 const struct file_operations
*fops
)
5682 ret
= debugfs_create_file(name
, mode
, parent
, data
, fops
);
5684 pr_warning("Could not create debugfs '%s' entry\n", name
);
5690 static struct dentry
*trace_options_init_dentry(struct trace_array
*tr
)
5692 struct dentry
*d_tracer
;
5697 d_tracer
= tracing_init_dentry_tr(tr
);
5701 tr
->options
= debugfs_create_dir("options", d_tracer
);
5703 pr_warning("Could not create debugfs directory 'options'\n");
5711 create_trace_option_file(struct trace_array
*tr
,
5712 struct trace_option_dentry
*topt
,
5713 struct tracer_flags
*flags
,
5714 struct tracer_opt
*opt
)
5716 struct dentry
*t_options
;
5718 t_options
= trace_options_init_dentry(tr
);
5722 topt
->flags
= flags
;
5726 topt
->entry
= trace_create_file(opt
->name
, 0644, t_options
, topt
,
5727 &trace_options_fops
);
5731 static struct trace_option_dentry
*
5732 create_trace_option_files(struct trace_array
*tr
, struct tracer
*tracer
)
5734 struct trace_option_dentry
*topts
;
5735 struct tracer_flags
*flags
;
5736 struct tracer_opt
*opts
;
5742 flags
= tracer
->flags
;
5744 if (!flags
|| !flags
->opts
)
5749 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
5752 topts
= kcalloc(cnt
+ 1, sizeof(*topts
), GFP_KERNEL
);
5756 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
5757 create_trace_option_file(tr
, &topts
[cnt
], flags
,
5764 destroy_trace_option_files(struct trace_option_dentry
*topts
)
5771 for (cnt
= 0; topts
[cnt
].opt
; cnt
++) {
5772 if (topts
[cnt
].entry
)
5773 debugfs_remove(topts
[cnt
].entry
);
5779 static struct dentry
*
5780 create_trace_option_core_file(struct trace_array
*tr
,
5781 const char *option
, long index
)
5783 struct dentry
*t_options
;
5785 t_options
= trace_options_init_dentry(tr
);
5789 return trace_create_file(option
, 0644, t_options
, (void *)index
,
5790 &trace_options_core_fops
);
5793 static __init
void create_trace_options_dir(struct trace_array
*tr
)
5795 struct dentry
*t_options
;
5798 t_options
= trace_options_init_dentry(tr
);
5802 for (i
= 0; trace_options
[i
]; i
++)
5803 create_trace_option_core_file(tr
, trace_options
[i
], i
);
5807 rb_simple_read(struct file
*filp
, char __user
*ubuf
,
5808 size_t cnt
, loff_t
*ppos
)
5810 struct trace_array
*tr
= filp
->private_data
;
5814 r
= tracer_tracing_is_on(tr
);
5815 r
= sprintf(buf
, "%d\n", r
);
5817 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
5821 rb_simple_write(struct file
*filp
, const char __user
*ubuf
,
5822 size_t cnt
, loff_t
*ppos
)
5824 struct trace_array
*tr
= filp
->private_data
;
5825 struct ring_buffer
*buffer
= tr
->trace_buffer
.buffer
;
5829 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5834 mutex_lock(&trace_types_lock
);
5836 tracer_tracing_on(tr
);
5837 if (tr
->current_trace
->start
)
5838 tr
->current_trace
->start(tr
);
5840 tracer_tracing_off(tr
);
5841 if (tr
->current_trace
->stop
)
5842 tr
->current_trace
->stop(tr
);
5844 mutex_unlock(&trace_types_lock
);
5852 static const struct file_operations rb_simple_fops
= {
5853 .open
= tracing_open_generic_tr
,
5854 .read
= rb_simple_read
,
5855 .write
= rb_simple_write
,
5856 .release
= tracing_release_generic_tr
,
5857 .llseek
= default_llseek
,
5860 struct dentry
*trace_instance_dir
;
5863 init_tracer_debugfs(struct trace_array
*tr
, struct dentry
*d_tracer
);
5866 allocate_trace_buffer(struct trace_array
*tr
, struct trace_buffer
*buf
, int size
)
5868 enum ring_buffer_flags rb_flags
;
5870 rb_flags
= trace_flags
& TRACE_ITER_OVERWRITE
? RB_FL_OVERWRITE
: 0;
5872 buf
->buffer
= ring_buffer_alloc(size
, rb_flags
);
5876 buf
->data
= alloc_percpu(struct trace_array_cpu
);
5878 ring_buffer_free(buf
->buffer
);
5882 /* Allocate the first page for all buffers */
5883 set_buffer_entries(&tr
->trace_buffer
,
5884 ring_buffer_size(tr
->trace_buffer
.buffer
, 0));
5889 static int allocate_trace_buffers(struct trace_array
*tr
, int size
)
5893 ret
= allocate_trace_buffer(tr
, &tr
->trace_buffer
, size
);
5897 #ifdef CONFIG_TRACER_MAX_TRACE
5898 ret
= allocate_trace_buffer(tr
, &tr
->max_buffer
,
5899 allocate_snapshot
? size
: 1);
5901 ring_buffer_free(tr
->trace_buffer
.buffer
);
5902 free_percpu(tr
->trace_buffer
.data
);
5905 tr
->allocated_snapshot
= allocate_snapshot
;
5908 * Only the top level trace array gets its snapshot allocated
5909 * from the kernel command line.
5911 allocate_snapshot
= false;
5916 static int new_instance_create(const char *name
)
5918 struct trace_array
*tr
;
5921 mutex_lock(&trace_types_lock
);
5924 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
5925 if (tr
->name
&& strcmp(tr
->name
, name
) == 0)
5930 tr
= kzalloc(sizeof(*tr
), GFP_KERNEL
);
5934 tr
->name
= kstrdup(name
, GFP_KERNEL
);
5938 if (!alloc_cpumask_var(&tr
->tracing_cpumask
, GFP_KERNEL
))
5941 cpumask_copy(tr
->tracing_cpumask
, cpu_all_mask
);
5943 raw_spin_lock_init(&tr
->start_lock
);
5945 tr
->current_trace
= &nop_trace
;
5947 INIT_LIST_HEAD(&tr
->systems
);
5948 INIT_LIST_HEAD(&tr
->events
);
5950 if (allocate_trace_buffers(tr
, trace_buf_size
) < 0)
5953 tr
->dir
= debugfs_create_dir(name
, trace_instance_dir
);
5957 ret
= event_trace_add_tracer(tr
->dir
, tr
);
5959 debugfs_remove_recursive(tr
->dir
);
5963 init_tracer_debugfs(tr
, tr
->dir
);
5965 list_add(&tr
->list
, &ftrace_trace_arrays
);
5967 mutex_unlock(&trace_types_lock
);
5972 if (tr
->trace_buffer
.buffer
)
5973 ring_buffer_free(tr
->trace_buffer
.buffer
);
5974 free_cpumask_var(tr
->tracing_cpumask
);
5979 mutex_unlock(&trace_types_lock
);
5985 static int instance_delete(const char *name
)
5987 struct trace_array
*tr
;
5991 mutex_lock(&trace_types_lock
);
5994 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
5995 if (tr
->name
&& strcmp(tr
->name
, name
) == 0) {
6007 list_del(&tr
->list
);
6009 event_trace_del_tracer(tr
);
6010 debugfs_remove_recursive(tr
->dir
);
6011 free_percpu(tr
->trace_buffer
.data
);
6012 ring_buffer_free(tr
->trace_buffer
.buffer
);
6020 mutex_unlock(&trace_types_lock
);
6025 static int instance_mkdir (struct inode
*inode
, struct dentry
*dentry
, umode_t mode
)
6027 struct dentry
*parent
;
6030 /* Paranoid: Make sure the parent is the "instances" directory */
6031 parent
= hlist_entry(inode
->i_dentry
.first
, struct dentry
, d_alias
);
6032 if (WARN_ON_ONCE(parent
!= trace_instance_dir
))
6036 * The inode mutex is locked, but debugfs_create_dir() will also
6037 * take the mutex. As the instances directory can not be destroyed
6038 * or changed in any other way, it is safe to unlock it, and
6039 * let the dentry try. If two users try to make the same dir at
6040 * the same time, then the new_instance_create() will determine the
6043 mutex_unlock(&inode
->i_mutex
);
6045 ret
= new_instance_create(dentry
->d_iname
);
6047 mutex_lock(&inode
->i_mutex
);
6052 static int instance_rmdir(struct inode
*inode
, struct dentry
*dentry
)
6054 struct dentry
*parent
;
6057 /* Paranoid: Make sure the parent is the "instances" directory */
6058 parent
= hlist_entry(inode
->i_dentry
.first
, struct dentry
, d_alias
);
6059 if (WARN_ON_ONCE(parent
!= trace_instance_dir
))
6062 /* The caller did a dget() on dentry */
6063 mutex_unlock(&dentry
->d_inode
->i_mutex
);
6066 * The inode mutex is locked, but debugfs_create_dir() will also
6067 * take the mutex. As the instances directory can not be destroyed
6068 * or changed in any other way, it is safe to unlock it, and
6069 * let the dentry try. If two users try to make the same dir at
6070 * the same time, then the instance_delete() will determine the
6073 mutex_unlock(&inode
->i_mutex
);
6075 ret
= instance_delete(dentry
->d_iname
);
6077 mutex_lock_nested(&inode
->i_mutex
, I_MUTEX_PARENT
);
6078 mutex_lock(&dentry
->d_inode
->i_mutex
);
6083 static const struct inode_operations instance_dir_inode_operations
= {
6084 .lookup
= simple_lookup
,
6085 .mkdir
= instance_mkdir
,
6086 .rmdir
= instance_rmdir
,
6089 static __init
void create_trace_instances(struct dentry
*d_tracer
)
6091 trace_instance_dir
= debugfs_create_dir("instances", d_tracer
);
6092 if (WARN_ON(!trace_instance_dir
))
6095 /* Hijack the dir inode operations, to allow mkdir */
6096 trace_instance_dir
->d_inode
->i_op
= &instance_dir_inode_operations
;
6100 init_tracer_debugfs(struct trace_array
*tr
, struct dentry
*d_tracer
)
6104 trace_create_file("tracing_cpumask", 0644, d_tracer
,
6105 tr
, &tracing_cpumask_fops
);
6107 trace_create_file("trace_options", 0644, d_tracer
,
6108 tr
, &tracing_iter_fops
);
6110 trace_create_file("trace", 0644, d_tracer
,
6113 trace_create_file("trace_pipe", 0444, d_tracer
,
6114 tr
, &tracing_pipe_fops
);
6116 trace_create_file("buffer_size_kb", 0644, d_tracer
,
6117 tr
, &tracing_entries_fops
);
6119 trace_create_file("buffer_total_size_kb", 0444, d_tracer
,
6120 tr
, &tracing_total_entries_fops
);
6122 trace_create_file("free_buffer", 0200, d_tracer
,
6123 tr
, &tracing_free_buffer_fops
);
6125 trace_create_file("trace_marker", 0220, d_tracer
,
6126 tr
, &tracing_mark_fops
);
6128 trace_create_file("trace_clock", 0644, d_tracer
, tr
,
6131 trace_create_file("tracing_on", 0644, d_tracer
,
6132 tr
, &rb_simple_fops
);
6134 #ifdef CONFIG_TRACER_SNAPSHOT
6135 trace_create_file("snapshot", 0644, d_tracer
,
6136 tr
, &snapshot_fops
);
6139 for_each_tracing_cpu(cpu
)
6140 tracing_init_debugfs_percpu(tr
, cpu
);
6144 static __init
int tracer_init_debugfs(void)
6146 struct dentry
*d_tracer
;
6148 trace_access_lock_init();
6150 d_tracer
= tracing_init_dentry();
6154 init_tracer_debugfs(&global_trace
, d_tracer
);
6156 trace_create_file("available_tracers", 0444, d_tracer
,
6157 &global_trace
, &show_traces_fops
);
6159 trace_create_file("current_tracer", 0644, d_tracer
,
6160 &global_trace
, &set_tracer_fops
);
6162 #ifdef CONFIG_TRACER_MAX_TRACE
6163 trace_create_file("tracing_max_latency", 0644, d_tracer
,
6164 &tracing_max_latency
, &tracing_max_lat_fops
);
6167 trace_create_file("tracing_thresh", 0644, d_tracer
,
6168 &tracing_thresh
, &tracing_max_lat_fops
);
6170 trace_create_file("README", 0444, d_tracer
,
6171 NULL
, &tracing_readme_fops
);
6173 trace_create_file("saved_cmdlines", 0444, d_tracer
,
6174 NULL
, &tracing_saved_cmdlines_fops
);
6176 #ifdef CONFIG_DYNAMIC_FTRACE
6177 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
6178 &ftrace_update_tot_cnt
, &tracing_dyn_info_fops
);
6181 create_trace_instances(d_tracer
);
6183 create_trace_options_dir(&global_trace
);
6188 static int trace_panic_handler(struct notifier_block
*this,
6189 unsigned long event
, void *unused
)
6191 if (ftrace_dump_on_oops
)
6192 ftrace_dump(ftrace_dump_on_oops
);
6196 static struct notifier_block trace_panic_notifier
= {
6197 .notifier_call
= trace_panic_handler
,
6199 .priority
= 150 /* priority: INT_MAX >= x >= 0 */
6202 static int trace_die_handler(struct notifier_block
*self
,
6208 if (ftrace_dump_on_oops
)
6209 ftrace_dump(ftrace_dump_on_oops
);
6217 static struct notifier_block trace_die_notifier
= {
6218 .notifier_call
= trace_die_handler
,
6223 * printk is set to max of 1024, we really don't need it that big.
6224 * Nothing should be printing 1000 characters anyway.
6226 #define TRACE_MAX_PRINT 1000
6229 * Define here KERN_TRACE so that we have one place to modify
6230 * it if we decide to change what log level the ftrace dump
6233 #define KERN_TRACE KERN_EMERG
6236 trace_printk_seq(struct trace_seq
*s
)
6238 /* Probably should print a warning here. */
6239 if (s
->len
>= TRACE_MAX_PRINT
)
6240 s
->len
= TRACE_MAX_PRINT
;
6242 /* should be zero ended, but we are paranoid. */
6243 s
->buffer
[s
->len
] = 0;
6245 printk(KERN_TRACE
"%s", s
->buffer
);
6250 void trace_init_global_iter(struct trace_iterator
*iter
)
6252 iter
->tr
= &global_trace
;
6253 iter
->trace
= iter
->tr
->current_trace
;
6254 iter
->cpu_file
= RING_BUFFER_ALL_CPUS
;
6255 iter
->trace_buffer
= &global_trace
.trace_buffer
;
6258 void ftrace_dump(enum ftrace_dump_mode oops_dump_mode
)
6260 /* use static because iter can be a bit big for the stack */
6261 static struct trace_iterator iter
;
6262 static atomic_t dump_running
;
6263 unsigned int old_userobj
;
6264 unsigned long flags
;
6267 /* Only allow one dump user at a time. */
6268 if (atomic_inc_return(&dump_running
) != 1) {
6269 atomic_dec(&dump_running
);
6274 * Always turn off tracing when we dump.
6275 * We don't need to show trace output of what happens
6276 * between multiple crashes.
6278 * If the user does a sysrq-z, then they can re-enable
6279 * tracing with echo 1 > tracing_on.
6283 local_irq_save(flags
);
6285 /* Simulate the iterator */
6286 trace_init_global_iter(&iter
);
6288 for_each_tracing_cpu(cpu
) {
6289 atomic_inc(&per_cpu_ptr(iter
.tr
->trace_buffer
.data
, cpu
)->disabled
);
6292 old_userobj
= trace_flags
& TRACE_ITER_SYM_USEROBJ
;
6294 /* don't look at user memory in panic mode */
6295 trace_flags
&= ~TRACE_ITER_SYM_USEROBJ
;
6297 switch (oops_dump_mode
) {
6299 iter
.cpu_file
= RING_BUFFER_ALL_CPUS
;
6302 iter
.cpu_file
= raw_smp_processor_id();
6307 printk(KERN_TRACE
"Bad dumping mode, switching to all CPUs dump\n");
6308 iter
.cpu_file
= RING_BUFFER_ALL_CPUS
;
6311 printk(KERN_TRACE
"Dumping ftrace buffer:\n");
6313 /* Did function tracer already get disabled? */
6314 if (ftrace_is_dead()) {
6315 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
6316 printk("# MAY BE MISSING FUNCTION EVENTS\n");
6320 * We need to stop all tracing on all CPUS to read the
6321 * the next buffer. This is a bit expensive, but is
6322 * not done often. We fill all what we can read,
6323 * and then release the locks again.
6326 while (!trace_empty(&iter
)) {
6329 printk(KERN_TRACE
"---------------------------------\n");
6333 /* reset all but tr, trace, and overruns */
6334 memset(&iter
.seq
, 0,
6335 sizeof(struct trace_iterator
) -
6336 offsetof(struct trace_iterator
, seq
));
6337 iter
.iter_flags
|= TRACE_FILE_LAT_FMT
;
6340 if (trace_find_next_entry_inc(&iter
) != NULL
) {
6343 ret
= print_trace_line(&iter
);
6344 if (ret
!= TRACE_TYPE_NO_CONSUME
)
6345 trace_consume(&iter
);
6347 touch_nmi_watchdog();
6349 trace_printk_seq(&iter
.seq
);
6353 printk(KERN_TRACE
" (ftrace buffer empty)\n");
6355 printk(KERN_TRACE
"---------------------------------\n");
6358 trace_flags
|= old_userobj
;
6360 for_each_tracing_cpu(cpu
) {
6361 atomic_dec(&per_cpu_ptr(iter
.trace_buffer
->data
, cpu
)->disabled
);
6363 atomic_dec(&dump_running
);
6364 local_irq_restore(flags
);
6366 EXPORT_SYMBOL_GPL(ftrace_dump
);
6368 __init
static int tracer_alloc_buffers(void)
6374 if (!alloc_cpumask_var(&tracing_buffer_mask
, GFP_KERNEL
))
6377 if (!alloc_cpumask_var(&global_trace
.tracing_cpumask
, GFP_KERNEL
))
6378 goto out_free_buffer_mask
;
6380 /* Only allocate trace_printk buffers if a trace_printk exists */
6381 if (__stop___trace_bprintk_fmt
!= __start___trace_bprintk_fmt
)
6382 /* Must be called before global_trace.buffer is allocated */
6383 trace_printk_init_buffers();
6385 /* To save memory, keep the ring buffer size to its minimum */
6386 if (ring_buffer_expanded
)
6387 ring_buf_size
= trace_buf_size
;
6391 cpumask_copy(tracing_buffer_mask
, cpu_possible_mask
);
6392 cpumask_copy(global_trace
.tracing_cpumask
, cpu_all_mask
);
6394 raw_spin_lock_init(&global_trace
.start_lock
);
6396 /* TODO: make the number of buffers hot pluggable with CPUS */
6397 if (allocate_trace_buffers(&global_trace
, ring_buf_size
) < 0) {
6398 printk(KERN_ERR
"tracer: failed to allocate ring buffer!\n");
6400 goto out_free_cpumask
;
6403 if (global_trace
.buffer_disabled
)
6406 trace_init_cmdlines();
6409 * register_tracer() might reference current_trace, so it
6410 * needs to be set before we register anything. This is
6411 * just a bootstrap of current_trace anyway.
6413 global_trace
.current_trace
= &nop_trace
;
6415 register_tracer(&nop_trace
);
6417 /* All seems OK, enable tracing */
6418 tracing_disabled
= 0;
6420 atomic_notifier_chain_register(&panic_notifier_list
,
6421 &trace_panic_notifier
);
6423 register_die_notifier(&trace_die_notifier
);
6425 global_trace
.flags
= TRACE_ARRAY_FL_GLOBAL
;
6427 INIT_LIST_HEAD(&global_trace
.systems
);
6428 INIT_LIST_HEAD(&global_trace
.events
);
6429 list_add(&global_trace
.list
, &ftrace_trace_arrays
);
6431 while (trace_boot_options
) {
6434 option
= strsep(&trace_boot_options
, ",");
6435 trace_set_options(&global_trace
, option
);
6438 register_snapshot_cmd();
6443 free_percpu(global_trace
.trace_buffer
.data
);
6444 #ifdef CONFIG_TRACER_MAX_TRACE
6445 free_percpu(global_trace
.max_buffer
.data
);
6447 free_cpumask_var(global_trace
.tracing_cpumask
);
6448 out_free_buffer_mask
:
6449 free_cpumask_var(tracing_buffer_mask
);
6454 __init
static int clear_boot_tracer(void)
6457 * The default tracer at boot buffer is an init section.
6458 * This function is called in lateinit. If we did not
6459 * find the boot tracer, then clear it out, to prevent
6460 * later registration from accessing the buffer that is
6461 * about to be freed.
6463 if (!default_bootup_tracer
)
6466 printk(KERN_INFO
"ftrace bootup tracer '%s' not registered.\n",
6467 default_bootup_tracer
);
6468 default_bootup_tracer
= NULL
;
6473 early_initcall(tracer_alloc_buffers
);
6474 fs_initcall(tracer_init_debugfs
);
6475 late_initcall(clear_boot_tracer
);