2 * ring buffer based function tracer
4 * Copyright (C) 2007-2008 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 William Lee Irwin III
14 #include <linux/ring_buffer.h>
15 #include <linux/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/ctype.h>
35 #include <linux/init.h>
36 #include <linux/poll.h>
37 #include <linux/gfp.h>
41 #include "trace_output.h"
43 #define TRACE_BUFFER_FLAGS (RB_FL_OVERWRITE)
45 unsigned long __read_mostly tracing_max_latency
;
46 unsigned long __read_mostly tracing_thresh
;
49 * On boot up, the ring buffer is set to the minimum size, so that
50 * we do not waste memory on systems that are not using tracing.
52 static int ring_buffer_expanded
;
55 * We need to change this state when a selftest is running.
56 * A selftest will lurk into the ring-buffer to count the
57 * entries inserted during the selftest although some concurrent
58 * insertions into the ring-buffer such as trace_printk could occurred
59 * at the same time, giving false positive or negative results.
61 static bool __read_mostly tracing_selftest_running
;
64 * If a tracer is running, we do not want to run SELFTEST.
66 static bool __read_mostly tracing_selftest_disabled
;
68 /* For tracers that don't implement custom flags */
69 static struct tracer_opt dummy_tracer_opt
[] = {
73 static struct tracer_flags dummy_tracer_flags
= {
75 .opts
= dummy_tracer_opt
78 static int dummy_set_flag(u32 old_flags
, u32 bit
, int set
)
84 * Kill all tracing for good (never come back).
85 * It is initialized to 1 but will turn to zero if the initialization
86 * of the tracer is successful. But that is the only place that sets
89 static int tracing_disabled
= 1;
91 static DEFINE_PER_CPU(local_t
, ftrace_cpu_disabled
);
93 static inline void ftrace_disable_cpu(void)
96 local_inc(&__get_cpu_var(ftrace_cpu_disabled
));
99 static inline void ftrace_enable_cpu(void)
101 local_dec(&__get_cpu_var(ftrace_cpu_disabled
));
105 static cpumask_var_t __read_mostly tracing_buffer_mask
;
107 /* Define which cpu buffers are currently read in trace_pipe */
108 static cpumask_var_t tracing_reader_cpumask
;
110 #define for_each_tracing_cpu(cpu) \
111 for_each_cpu(cpu, tracing_buffer_mask)
114 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
116 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
117 * is set, then ftrace_dump is called. This will output the contents
118 * of the ftrace buffers to the console. This is very useful for
119 * capturing traces that lead to crashes and outputing it to a
122 * It is default off, but you can enable it with either specifying
123 * "ftrace_dump_on_oops" in the kernel command line, or setting
124 * /proc/sys/kernel/ftrace_dump_on_oops to true.
126 int ftrace_dump_on_oops
;
128 static int tracing_set_tracer(const char *buf
);
130 #define BOOTUP_TRACER_SIZE 100
131 static char bootup_tracer_buf
[BOOTUP_TRACER_SIZE
] __initdata
;
132 static char *default_bootup_tracer
;
134 static int __init
set_ftrace(char *str
)
136 strncpy(bootup_tracer_buf
, str
, BOOTUP_TRACER_SIZE
);
137 default_bootup_tracer
= bootup_tracer_buf
;
138 /* We are using ftrace early, expand it */
139 ring_buffer_expanded
= 1;
142 __setup("ftrace=", set_ftrace
);
144 static int __init
set_ftrace_dump_on_oops(char *str
)
146 ftrace_dump_on_oops
= 1;
149 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops
);
151 unsigned long long ns2usecs(cycle_t nsec
)
159 * The global_trace is the descriptor that holds the tracing
160 * buffers for the live tracing. For each CPU, it contains
161 * a link list of pages that will store trace entries. The
162 * page descriptor of the pages in the memory is used to hold
163 * the link list by linking the lru item in the page descriptor
164 * to each of the pages in the buffer per CPU.
166 * For each active CPU there is a data field that holds the
167 * pages for the buffer for that CPU. Each CPU has the same number
168 * of pages allocated for its buffer.
170 static struct trace_array global_trace
;
172 static DEFINE_PER_CPU(struct trace_array_cpu
, global_trace_cpu
);
174 int filter_current_check_discard(struct ftrace_event_call
*call
, void *rec
,
175 struct ring_buffer_event
*event
)
177 return filter_check_discard(call
, rec
, global_trace
.buffer
, event
);
179 EXPORT_SYMBOL_GPL(filter_current_check_discard
);
181 cycle_t
ftrace_now(int cpu
)
185 /* Early boot up does not have a buffer yet */
186 if (!global_trace
.buffer
)
187 return trace_clock_local();
189 ts
= ring_buffer_time_stamp(global_trace
.buffer
, cpu
);
190 ring_buffer_normalize_time_stamp(global_trace
.buffer
, cpu
, &ts
);
196 * The max_tr is used to snapshot the global_trace when a maximum
197 * latency is reached. Some tracers will use this to store a maximum
198 * trace while it continues examining live traces.
200 * The buffers for the max_tr are set up the same as the global_trace.
201 * When a snapshot is taken, the link list of the max_tr is swapped
202 * with the link list of the global_trace and the buffers are reset for
203 * the global_trace so the tracing can continue.
205 static struct trace_array max_tr
;
207 static DEFINE_PER_CPU(struct trace_array_cpu
, max_data
);
209 /* tracer_enabled is used to toggle activation of a tracer */
210 static int tracer_enabled
= 1;
213 * tracing_is_enabled - return tracer_enabled status
215 * This function is used by other tracers to know the status
216 * of the tracer_enabled flag. Tracers may use this function
217 * to know if it should enable their features when starting
218 * up. See irqsoff tracer for an example (start_irqsoff_tracer).
220 int tracing_is_enabled(void)
222 return tracer_enabled
;
226 * trace_buf_size is the size in bytes that is allocated
227 * for a buffer. Note, the number of bytes is always rounded
230 * This number is purposely set to a low number of 16384.
231 * If the dump on oops happens, it will be much appreciated
232 * to not have to wait for all that output. Anyway this can be
233 * boot time and run time configurable.
235 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
237 static unsigned long trace_buf_size
= TRACE_BUF_SIZE_DEFAULT
;
239 /* trace_types holds a link list of available tracers. */
240 static struct tracer
*trace_types __read_mostly
;
242 /* current_trace points to the tracer that is currently active */
243 static struct tracer
*current_trace __read_mostly
;
246 * max_tracer_type_len is used to simplify the allocating of
247 * buffers to read userspace tracer names. We keep track of
248 * the longest tracer name registered.
250 static int max_tracer_type_len
;
253 * trace_types_lock is used to protect the trace_types list.
254 * This lock is also used to keep user access serialized.
255 * Accesses from userspace will grab this lock while userspace
256 * activities happen inside the kernel.
258 static DEFINE_MUTEX(trace_types_lock
);
260 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
261 static DECLARE_WAIT_QUEUE_HEAD(trace_wait
);
263 /* trace_flags holds trace_options default values */
264 unsigned long trace_flags
= TRACE_ITER_PRINT_PARENT
| TRACE_ITER_PRINTK
|
265 TRACE_ITER_ANNOTATE
| TRACE_ITER_CONTEXT_INFO
| TRACE_ITER_SLEEP_TIME
|
266 TRACE_ITER_GRAPH_TIME
;
269 * trace_wake_up - wake up tasks waiting for trace input
271 * Simply wakes up any task that is blocked on the trace_wait
272 * queue. These is used with trace_poll for tasks polling the trace.
274 void trace_wake_up(void)
277 * The runqueue_is_locked() can fail, but this is the best we
280 if (!(trace_flags
& TRACE_ITER_BLOCK
) && !runqueue_is_locked())
281 wake_up(&trace_wait
);
284 static int __init
set_buf_size(char *str
)
286 unsigned long buf_size
;
290 buf_size
= memparse(str
, &str
);
291 /* nr_entries can not be zero */
294 trace_buf_size
= buf_size
;
297 __setup("trace_buf_size=", set_buf_size
);
299 unsigned long nsecs_to_usecs(unsigned long nsecs
)
304 /* These must match the bit postions in trace_iterator_flags */
305 static const char *trace_options
[] = {
332 * ftrace_max_lock is used to protect the swapping of buffers
333 * when taking a max snapshot. The buffers themselves are
334 * protected by per_cpu spinlocks. But the action of the swap
335 * needs its own lock.
337 * This is defined as a raw_spinlock_t in order to help
338 * with performance when lockdep debugging is enabled.
340 static raw_spinlock_t ftrace_max_lock
=
341 (raw_spinlock_t
)__RAW_SPIN_LOCK_UNLOCKED
;
344 * Copy the new maximum trace into the separate maximum-trace
345 * structure. (this way the maximum trace is permanently saved,
346 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
349 __update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
351 struct trace_array_cpu
*data
= tr
->data
[cpu
];
354 max_tr
.time_start
= data
->preempt_timestamp
;
356 data
= max_tr
.data
[cpu
];
357 data
->saved_latency
= tracing_max_latency
;
359 memcpy(data
->comm
, tsk
->comm
, TASK_COMM_LEN
);
360 data
->pid
= tsk
->pid
;
361 data
->uid
= task_uid(tsk
);
362 data
->nice
= tsk
->static_prio
- 20 - MAX_RT_PRIO
;
363 data
->policy
= tsk
->policy
;
364 data
->rt_priority
= tsk
->rt_priority
;
366 /* record this tasks comm */
367 tracing_record_cmdline(tsk
);
370 ssize_t
trace_seq_to_user(struct trace_seq
*s
, char __user
*ubuf
, size_t cnt
)
378 if (s
->len
<= s
->readpos
)
381 len
= s
->len
- s
->readpos
;
384 ret
= copy_to_user(ubuf
, s
->buffer
+ s
->readpos
, cnt
);
394 static ssize_t
trace_seq_to_buffer(struct trace_seq
*s
, void *buf
, size_t cnt
)
399 if (s
->len
<= s
->readpos
)
402 len
= s
->len
- s
->readpos
;
405 ret
= memcpy(buf
, s
->buffer
+ s
->readpos
, cnt
);
414 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
416 * @tsk: the task with the latency
417 * @cpu: The cpu that initiated the trace.
419 * Flip the buffers between the @tr and the max_tr and record information
420 * about which task was the cause of this latency.
423 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
425 struct ring_buffer
*buf
= tr
->buffer
;
427 WARN_ON_ONCE(!irqs_disabled());
428 __raw_spin_lock(&ftrace_max_lock
);
430 tr
->buffer
= max_tr
.buffer
;
433 ftrace_disable_cpu();
434 ring_buffer_reset(tr
->buffer
);
437 __update_max_tr(tr
, tsk
, cpu
);
438 __raw_spin_unlock(&ftrace_max_lock
);
442 * update_max_tr_single - only copy one trace over, and reset the rest
444 * @tsk - task with the latency
445 * @cpu - the cpu of the buffer to copy.
447 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
450 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
454 WARN_ON_ONCE(!irqs_disabled());
455 __raw_spin_lock(&ftrace_max_lock
);
457 ftrace_disable_cpu();
459 ring_buffer_reset(max_tr
.buffer
);
460 ret
= ring_buffer_swap_cpu(max_tr
.buffer
, tr
->buffer
, cpu
);
464 WARN_ON_ONCE(ret
&& ret
!= -EAGAIN
);
466 __update_max_tr(tr
, tsk
, cpu
);
467 __raw_spin_unlock(&ftrace_max_lock
);
471 * register_tracer - register a tracer with the ftrace system.
472 * @type - the plugin for the tracer
474 * Register a new plugin tracer.
476 int register_tracer(struct tracer
*type
)
477 __releases(kernel_lock
)
478 __acquires(kernel_lock
)
485 pr_info("Tracer must have a name\n");
490 * When this gets called we hold the BKL which means that
491 * preemption is disabled. Various trace selftests however
492 * need to disable and enable preemption for successful tests.
493 * So we drop the BKL here and grab it after the tests again.
496 mutex_lock(&trace_types_lock
);
498 tracing_selftest_running
= true;
500 for (t
= trace_types
; t
; t
= t
->next
) {
501 if (strcmp(type
->name
, t
->name
) == 0) {
503 pr_info("Trace %s already registered\n",
511 type
->set_flag
= &dummy_set_flag
;
513 type
->flags
= &dummy_tracer_flags
;
515 if (!type
->flags
->opts
)
516 type
->flags
->opts
= dummy_tracer_opt
;
517 if (!type
->wait_pipe
)
518 type
->wait_pipe
= default_wait_pipe
;
521 #ifdef CONFIG_FTRACE_STARTUP_TEST
522 if (type
->selftest
&& !tracing_selftest_disabled
) {
523 struct tracer
*saved_tracer
= current_trace
;
524 struct trace_array
*tr
= &global_trace
;
528 * Run a selftest on this tracer.
529 * Here we reset the trace buffer, and set the current
530 * tracer to be this tracer. The tracer can then run some
531 * internal tracing to verify that everything is in order.
532 * If we fail, we do not register this tracer.
534 for_each_tracing_cpu(i
)
535 tracing_reset(tr
, i
);
537 current_trace
= type
;
538 /* the test is responsible for initializing and enabling */
539 pr_info("Testing tracer %s: ", type
->name
);
540 ret
= type
->selftest(type
, tr
);
541 /* the test is responsible for resetting too */
542 current_trace
= saved_tracer
;
544 printk(KERN_CONT
"FAILED!\n");
547 /* Only reset on passing, to avoid touching corrupted buffers */
548 for_each_tracing_cpu(i
)
549 tracing_reset(tr
, i
);
551 printk(KERN_CONT
"PASSED\n");
555 type
->next
= trace_types
;
557 len
= strlen(type
->name
);
558 if (len
> max_tracer_type_len
)
559 max_tracer_type_len
= len
;
562 tracing_selftest_running
= false;
563 mutex_unlock(&trace_types_lock
);
565 if (ret
|| !default_bootup_tracer
)
568 if (strncmp(default_bootup_tracer
, type
->name
, BOOTUP_TRACER_SIZE
))
571 printk(KERN_INFO
"Starting tracer '%s'\n", type
->name
);
572 /* Do we want this tracer to start on bootup? */
573 tracing_set_tracer(type
->name
);
574 default_bootup_tracer
= NULL
;
575 /* disable other selftests, since this will break it. */
576 tracing_selftest_disabled
= 1;
577 #ifdef CONFIG_FTRACE_STARTUP_TEST
578 printk(KERN_INFO
"Disabling FTRACE selftests due to running tracer '%s'\n",
587 void unregister_tracer(struct tracer
*type
)
592 mutex_lock(&trace_types_lock
);
593 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
597 pr_info("Trace %s not registered\n", type
->name
);
603 if (type
== current_trace
&& tracer_enabled
) {
606 if (current_trace
->stop
)
607 current_trace
->stop(&global_trace
);
608 current_trace
= &nop_trace
;
611 if (strlen(type
->name
) != max_tracer_type_len
)
614 max_tracer_type_len
= 0;
615 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
616 len
= strlen((*t
)->name
);
617 if (len
> max_tracer_type_len
)
618 max_tracer_type_len
= len
;
621 mutex_unlock(&trace_types_lock
);
624 void tracing_reset(struct trace_array
*tr
, int cpu
)
626 ftrace_disable_cpu();
627 ring_buffer_reset_cpu(tr
->buffer
, cpu
);
631 void tracing_reset_online_cpus(struct trace_array
*tr
)
635 tr
->time_start
= ftrace_now(tr
->cpu
);
637 for_each_online_cpu(cpu
)
638 tracing_reset(tr
, cpu
);
641 void tracing_reset_current(int cpu
)
643 tracing_reset(&global_trace
, cpu
);
646 void tracing_reset_current_online_cpus(void)
648 tracing_reset_online_cpus(&global_trace
);
651 #define SAVED_CMDLINES 128
652 #define NO_CMDLINE_MAP UINT_MAX
653 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
654 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
655 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
656 static int cmdline_idx
;
657 static raw_spinlock_t trace_cmdline_lock
= __RAW_SPIN_LOCK_UNLOCKED
;
659 /* temporary disable recording */
660 static atomic_t trace_record_cmdline_disabled __read_mostly
;
662 static void trace_init_cmdlines(void)
664 memset(&map_pid_to_cmdline
, NO_CMDLINE_MAP
, sizeof(map_pid_to_cmdline
));
665 memset(&map_cmdline_to_pid
, NO_CMDLINE_MAP
, sizeof(map_cmdline_to_pid
));
669 static int trace_stop_count
;
670 static DEFINE_SPINLOCK(tracing_start_lock
);
673 * ftrace_off_permanent - disable all ftrace code permanently
675 * This should only be called when a serious anomally has
676 * been detected. This will turn off the function tracing,
677 * ring buffers, and other tracing utilites. It takes no
678 * locks and can be called from any context.
680 void ftrace_off_permanent(void)
682 tracing_disabled
= 1;
684 tracing_off_permanent();
688 * tracing_start - quick start of the tracer
690 * If tracing is enabled but was stopped by tracing_stop,
691 * this will start the tracer back up.
693 void tracing_start(void)
695 struct ring_buffer
*buffer
;
698 if (tracing_disabled
)
701 spin_lock_irqsave(&tracing_start_lock
, flags
);
702 if (--trace_stop_count
) {
703 if (trace_stop_count
< 0) {
704 /* Someone screwed up their debugging */
706 trace_stop_count
= 0;
712 buffer
= global_trace
.buffer
;
714 ring_buffer_record_enable(buffer
);
716 buffer
= max_tr
.buffer
;
718 ring_buffer_record_enable(buffer
);
722 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
726 * tracing_stop - quick stop of the tracer
728 * Light weight way to stop tracing. Use in conjunction with
731 void tracing_stop(void)
733 struct ring_buffer
*buffer
;
737 spin_lock_irqsave(&tracing_start_lock
, flags
);
738 if (trace_stop_count
++)
741 buffer
= global_trace
.buffer
;
743 ring_buffer_record_disable(buffer
);
745 buffer
= max_tr
.buffer
;
747 ring_buffer_record_disable(buffer
);
750 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
753 void trace_stop_cmdline_recording(void);
755 static void trace_save_cmdline(struct task_struct
*tsk
)
759 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
763 * It's not the end of the world if we don't get
764 * the lock, but we also don't want to spin
765 * nor do we want to disable interrupts,
766 * so if we miss here, then better luck next time.
768 if (!__raw_spin_trylock(&trace_cmdline_lock
))
771 idx
= map_pid_to_cmdline
[tsk
->pid
];
772 if (idx
== NO_CMDLINE_MAP
) {
773 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
776 * Check whether the cmdline buffer at idx has a pid
777 * mapped. We are going to overwrite that entry so we
778 * need to clear the map_pid_to_cmdline. Otherwise we
779 * would read the new comm for the old pid.
781 pid
= map_cmdline_to_pid
[idx
];
782 if (pid
!= NO_CMDLINE_MAP
)
783 map_pid_to_cmdline
[pid
] = NO_CMDLINE_MAP
;
785 map_cmdline_to_pid
[idx
] = tsk
->pid
;
786 map_pid_to_cmdline
[tsk
->pid
] = idx
;
791 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
793 __raw_spin_unlock(&trace_cmdline_lock
);
796 void trace_find_cmdline(int pid
, char comm
[])
801 strcpy(comm
, "<idle>");
805 if (pid
> PID_MAX_DEFAULT
) {
806 strcpy(comm
, "<...>");
811 __raw_spin_lock(&trace_cmdline_lock
);
812 map
= map_pid_to_cmdline
[pid
];
813 if (map
!= NO_CMDLINE_MAP
)
814 strcpy(comm
, saved_cmdlines
[map
]);
816 strcpy(comm
, "<...>");
818 __raw_spin_unlock(&trace_cmdline_lock
);
822 void tracing_record_cmdline(struct task_struct
*tsk
)
824 if (atomic_read(&trace_record_cmdline_disabled
) || !tracer_enabled
||
828 trace_save_cmdline(tsk
);
832 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
,
835 struct task_struct
*tsk
= current
;
837 entry
->preempt_count
= pc
& 0xff;
838 entry
->pid
= (tsk
) ? tsk
->pid
: 0;
839 entry
->tgid
= (tsk
) ? tsk
->tgid
: 0;
841 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
842 (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
844 TRACE_FLAG_IRQS_NOSUPPORT
|
846 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
847 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
848 (need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0);
851 struct ring_buffer_event
*trace_buffer_lock_reserve(struct trace_array
*tr
,
854 unsigned long flags
, int pc
)
856 struct ring_buffer_event
*event
;
858 event
= ring_buffer_lock_reserve(tr
->buffer
, len
);
860 struct trace_entry
*ent
= ring_buffer_event_data(event
);
862 tracing_generic_entry_update(ent
, flags
, pc
);
868 static void ftrace_trace_stack(struct trace_array
*tr
,
869 unsigned long flags
, int skip
, int pc
);
870 static void ftrace_trace_userstack(struct trace_array
*tr
,
871 unsigned long flags
, int pc
);
873 static inline void __trace_buffer_unlock_commit(struct trace_array
*tr
,
874 struct ring_buffer_event
*event
,
875 unsigned long flags
, int pc
,
878 ring_buffer_unlock_commit(tr
->buffer
, event
);
880 ftrace_trace_stack(tr
, flags
, 6, pc
);
881 ftrace_trace_userstack(tr
, flags
, pc
);
887 void trace_buffer_unlock_commit(struct trace_array
*tr
,
888 struct ring_buffer_event
*event
,
889 unsigned long flags
, int pc
)
891 __trace_buffer_unlock_commit(tr
, event
, flags
, pc
, 1);
894 struct ring_buffer_event
*
895 trace_current_buffer_lock_reserve(int type
, unsigned long len
,
896 unsigned long flags
, int pc
)
898 return trace_buffer_lock_reserve(&global_trace
,
899 type
, len
, flags
, pc
);
901 EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve
);
903 void trace_current_buffer_unlock_commit(struct ring_buffer_event
*event
,
904 unsigned long flags
, int pc
)
906 __trace_buffer_unlock_commit(&global_trace
, event
, flags
, pc
, 1);
908 EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit
);
910 void trace_nowake_buffer_unlock_commit(struct ring_buffer_event
*event
,
911 unsigned long flags
, int pc
)
913 __trace_buffer_unlock_commit(&global_trace
, event
, flags
, pc
, 0);
915 EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit
);
917 void trace_current_buffer_discard_commit(struct ring_buffer_event
*event
)
919 ring_buffer_discard_commit(global_trace
.buffer
, event
);
921 EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit
);
924 trace_function(struct trace_array
*tr
,
925 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
928 struct ftrace_event_call
*call
= &event_function
;
929 struct ring_buffer_event
*event
;
930 struct ftrace_entry
*entry
;
932 /* If we are reading the ring buffer, don't trace */
933 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
936 event
= trace_buffer_lock_reserve(tr
, TRACE_FN
, sizeof(*entry
),
940 entry
= ring_buffer_event_data(event
);
942 entry
->parent_ip
= parent_ip
;
944 if (!filter_check_discard(call
, entry
, tr
->buffer
, event
))
945 ring_buffer_unlock_commit(tr
->buffer
, event
);
948 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
949 static int __trace_graph_entry(struct trace_array
*tr
,
950 struct ftrace_graph_ent
*trace
,
954 struct ftrace_event_call
*call
= &event_funcgraph_entry
;
955 struct ring_buffer_event
*event
;
956 struct ftrace_graph_ent_entry
*entry
;
958 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
961 event
= trace_buffer_lock_reserve(&global_trace
, TRACE_GRAPH_ENT
,
962 sizeof(*entry
), flags
, pc
);
965 entry
= ring_buffer_event_data(event
);
966 entry
->graph_ent
= *trace
;
967 if (!filter_current_check_discard(call
, entry
, event
))
968 ring_buffer_unlock_commit(global_trace
.buffer
, event
);
973 static void __trace_graph_return(struct trace_array
*tr
,
974 struct ftrace_graph_ret
*trace
,
978 struct ftrace_event_call
*call
= &event_funcgraph_exit
;
979 struct ring_buffer_event
*event
;
980 struct ftrace_graph_ret_entry
*entry
;
982 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
985 event
= trace_buffer_lock_reserve(&global_trace
, TRACE_GRAPH_RET
,
986 sizeof(*entry
), flags
, pc
);
989 entry
= ring_buffer_event_data(event
);
991 if (!filter_current_check_discard(call
, entry
, event
))
992 ring_buffer_unlock_commit(global_trace
.buffer
, event
);
997 ftrace(struct trace_array
*tr
, struct trace_array_cpu
*data
,
998 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
1001 if (likely(!atomic_read(&data
->disabled
)))
1002 trace_function(tr
, ip
, parent_ip
, flags
, pc
);
1005 static void __ftrace_trace_stack(struct trace_array
*tr
,
1006 unsigned long flags
,
1009 #ifdef CONFIG_STACKTRACE
1010 struct ftrace_event_call
*call
= &event_kernel_stack
;
1011 struct ring_buffer_event
*event
;
1012 struct stack_entry
*entry
;
1013 struct stack_trace trace
;
1015 event
= trace_buffer_lock_reserve(tr
, TRACE_STACK
,
1016 sizeof(*entry
), flags
, pc
);
1019 entry
= ring_buffer_event_data(event
);
1020 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
1022 trace
.nr_entries
= 0;
1023 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1025 trace
.entries
= entry
->caller
;
1027 save_stack_trace(&trace
);
1028 if (!filter_check_discard(call
, entry
, tr
->buffer
, event
))
1029 ring_buffer_unlock_commit(tr
->buffer
, event
);
1033 static void ftrace_trace_stack(struct trace_array
*tr
,
1034 unsigned long flags
,
1037 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1040 __ftrace_trace_stack(tr
, flags
, skip
, pc
);
1043 void __trace_stack(struct trace_array
*tr
,
1044 unsigned long flags
,
1047 __ftrace_trace_stack(tr
, flags
, skip
, pc
);
1050 static void ftrace_trace_userstack(struct trace_array
*tr
,
1051 unsigned long flags
, int pc
)
1053 #ifdef CONFIG_STACKTRACE
1054 struct ftrace_event_call
*call
= &event_user_stack
;
1055 struct ring_buffer_event
*event
;
1056 struct userstack_entry
*entry
;
1057 struct stack_trace trace
;
1059 if (!(trace_flags
& TRACE_ITER_USERSTACKTRACE
))
1062 event
= trace_buffer_lock_reserve(tr
, TRACE_USER_STACK
,
1063 sizeof(*entry
), flags
, pc
);
1066 entry
= ring_buffer_event_data(event
);
1068 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
1070 trace
.nr_entries
= 0;
1071 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1073 trace
.entries
= entry
->caller
;
1075 save_stack_trace_user(&trace
);
1076 if (!filter_check_discard(call
, entry
, tr
->buffer
, event
))
1077 ring_buffer_unlock_commit(tr
->buffer
, event
);
1082 static void __trace_userstack(struct trace_array
*tr
, unsigned long flags
)
1084 ftrace_trace_userstack(tr
, flags
, preempt_count());
1089 ftrace_trace_special(void *__tr
,
1090 unsigned long arg1
, unsigned long arg2
, unsigned long arg3
,
1093 struct ring_buffer_event
*event
;
1094 struct trace_array
*tr
= __tr
;
1095 struct special_entry
*entry
;
1097 event
= trace_buffer_lock_reserve(tr
, TRACE_SPECIAL
,
1098 sizeof(*entry
), 0, pc
);
1101 entry
= ring_buffer_event_data(event
);
1105 trace_buffer_unlock_commit(tr
, event
, 0, pc
);
1109 __trace_special(void *__tr
, void *__data
,
1110 unsigned long arg1
, unsigned long arg2
, unsigned long arg3
)
1112 ftrace_trace_special(__tr
, arg1
, arg2
, arg3
, preempt_count());
1116 tracing_sched_switch_trace(struct trace_array
*tr
,
1117 struct task_struct
*prev
,
1118 struct task_struct
*next
,
1119 unsigned long flags
, int pc
)
1121 struct ftrace_event_call
*call
= &event_context_switch
;
1122 struct ring_buffer_event
*event
;
1123 struct ctx_switch_entry
*entry
;
1125 event
= trace_buffer_lock_reserve(tr
, TRACE_CTX
,
1126 sizeof(*entry
), flags
, pc
);
1129 entry
= ring_buffer_event_data(event
);
1130 entry
->prev_pid
= prev
->pid
;
1131 entry
->prev_prio
= prev
->prio
;
1132 entry
->prev_state
= prev
->state
;
1133 entry
->next_pid
= next
->pid
;
1134 entry
->next_prio
= next
->prio
;
1135 entry
->next_state
= next
->state
;
1136 entry
->next_cpu
= task_cpu(next
);
1138 if (!filter_check_discard(call
, entry
, tr
->buffer
, event
))
1139 trace_buffer_unlock_commit(tr
, event
, flags
, pc
);
1143 tracing_sched_wakeup_trace(struct trace_array
*tr
,
1144 struct task_struct
*wakee
,
1145 struct task_struct
*curr
,
1146 unsigned long flags
, int pc
)
1148 struct ftrace_event_call
*call
= &event_wakeup
;
1149 struct ring_buffer_event
*event
;
1150 struct ctx_switch_entry
*entry
;
1152 event
= trace_buffer_lock_reserve(tr
, TRACE_WAKE
,
1153 sizeof(*entry
), flags
, pc
);
1156 entry
= ring_buffer_event_data(event
);
1157 entry
->prev_pid
= curr
->pid
;
1158 entry
->prev_prio
= curr
->prio
;
1159 entry
->prev_state
= curr
->state
;
1160 entry
->next_pid
= wakee
->pid
;
1161 entry
->next_prio
= wakee
->prio
;
1162 entry
->next_state
= wakee
->state
;
1163 entry
->next_cpu
= task_cpu(wakee
);
1165 if (!filter_check_discard(call
, entry
, tr
->buffer
, event
))
1166 ring_buffer_unlock_commit(tr
->buffer
, event
);
1167 ftrace_trace_stack(tr
, flags
, 6, pc
);
1168 ftrace_trace_userstack(tr
, flags
, pc
);
1172 ftrace_special(unsigned long arg1
, unsigned long arg2
, unsigned long arg3
)
1174 struct trace_array
*tr
= &global_trace
;
1175 struct trace_array_cpu
*data
;
1176 unsigned long flags
;
1180 if (tracing_disabled
)
1183 pc
= preempt_count();
1184 local_irq_save(flags
);
1185 cpu
= raw_smp_processor_id();
1186 data
= tr
->data
[cpu
];
1188 if (likely(atomic_inc_return(&data
->disabled
) == 1))
1189 ftrace_trace_special(tr
, arg1
, arg2
, arg3
, pc
);
1191 atomic_dec(&data
->disabled
);
1192 local_irq_restore(flags
);
1195 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1196 int trace_graph_entry(struct ftrace_graph_ent
*trace
)
1198 struct trace_array
*tr
= &global_trace
;
1199 struct trace_array_cpu
*data
;
1200 unsigned long flags
;
1206 if (!ftrace_trace_task(current
))
1209 if (!ftrace_graph_addr(trace
->func
))
1212 local_irq_save(flags
);
1213 cpu
= raw_smp_processor_id();
1214 data
= tr
->data
[cpu
];
1215 disabled
= atomic_inc_return(&data
->disabled
);
1216 if (likely(disabled
== 1)) {
1217 pc
= preempt_count();
1218 ret
= __trace_graph_entry(tr
, trace
, flags
, pc
);
1222 /* Only do the atomic if it is not already set */
1223 if (!test_tsk_trace_graph(current
))
1224 set_tsk_trace_graph(current
);
1226 atomic_dec(&data
->disabled
);
1227 local_irq_restore(flags
);
1232 void trace_graph_return(struct ftrace_graph_ret
*trace
)
1234 struct trace_array
*tr
= &global_trace
;
1235 struct trace_array_cpu
*data
;
1236 unsigned long flags
;
1241 local_irq_save(flags
);
1242 cpu
= raw_smp_processor_id();
1243 data
= tr
->data
[cpu
];
1244 disabled
= atomic_inc_return(&data
->disabled
);
1245 if (likely(disabled
== 1)) {
1246 pc
= preempt_count();
1247 __trace_graph_return(tr
, trace
, flags
, pc
);
1250 clear_tsk_trace_graph(current
);
1251 atomic_dec(&data
->disabled
);
1252 local_irq_restore(flags
);
1254 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1258 * trace_vbprintk - write binary msg to tracing buffer
1261 int trace_vbprintk(unsigned long ip
, const char *fmt
, va_list args
)
1263 static raw_spinlock_t trace_buf_lock
=
1264 (raw_spinlock_t
)__RAW_SPIN_LOCK_UNLOCKED
;
1265 static u32 trace_buf
[TRACE_BUF_SIZE
];
1267 struct ftrace_event_call
*call
= &event_bprint
;
1268 struct ring_buffer_event
*event
;
1269 struct trace_array
*tr
= &global_trace
;
1270 struct trace_array_cpu
*data
;
1271 struct bprint_entry
*entry
;
1272 unsigned long flags
;
1275 int cpu
, len
= 0, size
, pc
;
1277 if (unlikely(tracing_selftest_running
|| tracing_disabled
))
1280 /* Don't pollute graph traces with trace_vprintk internals */
1281 pause_graph_tracing();
1283 pc
= preempt_count();
1284 resched
= ftrace_preempt_disable();
1285 cpu
= raw_smp_processor_id();
1286 data
= tr
->data
[cpu
];
1288 disable
= atomic_inc_return(&data
->disabled
);
1289 if (unlikely(disable
!= 1))
1292 /* Lockdep uses trace_printk for lock tracing */
1293 local_irq_save(flags
);
1294 __raw_spin_lock(&trace_buf_lock
);
1295 len
= vbin_printf(trace_buf
, TRACE_BUF_SIZE
, fmt
, args
);
1297 if (len
> TRACE_BUF_SIZE
|| len
< 0)
1300 size
= sizeof(*entry
) + sizeof(u32
) * len
;
1301 event
= trace_buffer_lock_reserve(tr
, TRACE_BPRINT
, size
, flags
, pc
);
1304 entry
= ring_buffer_event_data(event
);
1308 memcpy(entry
->buf
, trace_buf
, sizeof(u32
) * len
);
1309 if (!filter_check_discard(call
, entry
, tr
->buffer
, event
))
1310 ring_buffer_unlock_commit(tr
->buffer
, event
);
1313 __raw_spin_unlock(&trace_buf_lock
);
1314 local_irq_restore(flags
);
1317 atomic_dec_return(&data
->disabled
);
1318 ftrace_preempt_enable(resched
);
1319 unpause_graph_tracing();
1323 EXPORT_SYMBOL_GPL(trace_vbprintk
);
1325 int trace_vprintk(unsigned long ip
, const char *fmt
, va_list args
)
1327 static raw_spinlock_t trace_buf_lock
= __RAW_SPIN_LOCK_UNLOCKED
;
1328 static char trace_buf
[TRACE_BUF_SIZE
];
1330 struct ftrace_event_call
*call
= &event_print
;
1331 struct ring_buffer_event
*event
;
1332 struct trace_array
*tr
= &global_trace
;
1333 struct trace_array_cpu
*data
;
1334 int cpu
, len
= 0, size
, pc
;
1335 struct print_entry
*entry
;
1336 unsigned long irq_flags
;
1339 if (tracing_disabled
|| tracing_selftest_running
)
1342 pc
= preempt_count();
1343 preempt_disable_notrace();
1344 cpu
= raw_smp_processor_id();
1345 data
= tr
->data
[cpu
];
1347 disable
= atomic_inc_return(&data
->disabled
);
1348 if (unlikely(disable
!= 1))
1351 pause_graph_tracing();
1352 raw_local_irq_save(irq_flags
);
1353 __raw_spin_lock(&trace_buf_lock
);
1354 len
= vsnprintf(trace_buf
, TRACE_BUF_SIZE
, fmt
, args
);
1356 len
= min(len
, TRACE_BUF_SIZE
-1);
1359 size
= sizeof(*entry
) + len
+ 1;
1360 event
= trace_buffer_lock_reserve(tr
, TRACE_PRINT
, size
, irq_flags
, pc
);
1363 entry
= ring_buffer_event_data(event
);
1366 memcpy(&entry
->buf
, trace_buf
, len
);
1367 entry
->buf
[len
] = 0;
1368 if (!filter_check_discard(call
, entry
, tr
->buffer
, event
))
1369 ring_buffer_unlock_commit(tr
->buffer
, event
);
1372 __raw_spin_unlock(&trace_buf_lock
);
1373 raw_local_irq_restore(irq_flags
);
1374 unpause_graph_tracing();
1376 atomic_dec_return(&data
->disabled
);
1377 preempt_enable_notrace();
1381 EXPORT_SYMBOL_GPL(trace_vprintk
);
1383 enum trace_file_type
{
1384 TRACE_FILE_LAT_FMT
= 1,
1385 TRACE_FILE_ANNOTATE
= 2,
1388 static void trace_iterator_increment(struct trace_iterator
*iter
)
1390 /* Don't allow ftrace to trace into the ring buffers */
1391 ftrace_disable_cpu();
1394 if (iter
->buffer_iter
[iter
->cpu
])
1395 ring_buffer_read(iter
->buffer_iter
[iter
->cpu
], NULL
);
1397 ftrace_enable_cpu();
1400 static struct trace_entry
*
1401 peek_next_entry(struct trace_iterator
*iter
, int cpu
, u64
*ts
)
1403 struct ring_buffer_event
*event
;
1404 struct ring_buffer_iter
*buf_iter
= iter
->buffer_iter
[cpu
];
1406 /* Don't allow ftrace to trace into the ring buffers */
1407 ftrace_disable_cpu();
1410 event
= ring_buffer_iter_peek(buf_iter
, ts
);
1412 event
= ring_buffer_peek(iter
->tr
->buffer
, cpu
, ts
);
1414 ftrace_enable_cpu();
1416 return event
? ring_buffer_event_data(event
) : NULL
;
1419 static struct trace_entry
*
1420 __find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
, u64
*ent_ts
)
1422 struct ring_buffer
*buffer
= iter
->tr
->buffer
;
1423 struct trace_entry
*ent
, *next
= NULL
;
1424 int cpu_file
= iter
->cpu_file
;
1425 u64 next_ts
= 0, ts
;
1430 * If we are in a per_cpu trace file, don't bother by iterating over
1431 * all cpu and peek directly.
1433 if (cpu_file
> TRACE_PIPE_ALL_CPU
) {
1434 if (ring_buffer_empty_cpu(buffer
, cpu_file
))
1436 ent
= peek_next_entry(iter
, cpu_file
, ent_ts
);
1438 *ent_cpu
= cpu_file
;
1443 for_each_tracing_cpu(cpu
) {
1445 if (ring_buffer_empty_cpu(buffer
, cpu
))
1448 ent
= peek_next_entry(iter
, cpu
, &ts
);
1451 * Pick the entry with the smallest timestamp:
1453 if (ent
&& (!next
|| ts
< next_ts
)) {
1461 *ent_cpu
= next_cpu
;
1469 /* Find the next real entry, without updating the iterator itself */
1470 struct trace_entry
*trace_find_next_entry(struct trace_iterator
*iter
,
1471 int *ent_cpu
, u64
*ent_ts
)
1473 return __find_next_entry(iter
, ent_cpu
, ent_ts
);
1476 /* Find the next real entry, and increment the iterator to the next entry */
1477 static void *find_next_entry_inc(struct trace_iterator
*iter
)
1479 iter
->ent
= __find_next_entry(iter
, &iter
->cpu
, &iter
->ts
);
1482 trace_iterator_increment(iter
);
1484 return iter
->ent
? iter
: NULL
;
1487 static void trace_consume(struct trace_iterator
*iter
)
1489 /* Don't allow ftrace to trace into the ring buffers */
1490 ftrace_disable_cpu();
1491 ring_buffer_consume(iter
->tr
->buffer
, iter
->cpu
, &iter
->ts
);
1492 ftrace_enable_cpu();
1495 static void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1497 struct trace_iterator
*iter
= m
->private;
1503 /* can't go backwards */
1508 ent
= find_next_entry_inc(iter
);
1512 while (ent
&& iter
->idx
< i
)
1513 ent
= find_next_entry_inc(iter
);
1521 * No necessary locking here. The worst thing which can
1522 * happen is loosing events consumed at the same time
1523 * by a trace_pipe reader.
1524 * Other than that, we don't risk to crash the ring buffer
1525 * because it serializes the readers.
1527 * The current tracer is copied to avoid a global locking
1530 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
1532 struct trace_iterator
*iter
= m
->private;
1533 static struct tracer
*old_tracer
;
1534 int cpu_file
= iter
->cpu_file
;
1539 /* copy the tracer to avoid using a global lock all around */
1540 mutex_lock(&trace_types_lock
);
1541 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
1542 old_tracer
= current_trace
;
1543 *iter
->trace
= *current_trace
;
1545 mutex_unlock(&trace_types_lock
);
1547 atomic_inc(&trace_record_cmdline_disabled
);
1549 if (*pos
!= iter
->pos
) {
1554 ftrace_disable_cpu();
1556 if (cpu_file
== TRACE_PIPE_ALL_CPU
) {
1557 for_each_tracing_cpu(cpu
)
1558 ring_buffer_iter_reset(iter
->buffer_iter
[cpu
]);
1560 ring_buffer_iter_reset(iter
->buffer_iter
[cpu_file
]);
1563 ftrace_enable_cpu();
1565 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
1570 p
= s_next(m
, p
, &l
);
1573 trace_event_read_lock();
1577 static void s_stop(struct seq_file
*m
, void *p
)
1579 atomic_dec(&trace_record_cmdline_disabled
);
1580 trace_event_read_unlock();
1583 static void print_lat_help_header(struct seq_file
*m
)
1585 seq_puts(m
, "# _------=> CPU# \n");
1586 seq_puts(m
, "# / _-----=> irqs-off \n");
1587 seq_puts(m
, "# | / _----=> need-resched \n");
1588 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
1589 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
1590 seq_puts(m
, "# |||| / \n");
1591 seq_puts(m
, "# ||||| delay \n");
1592 seq_puts(m
, "# cmd pid ||||| time | caller \n");
1593 seq_puts(m
, "# \\ / ||||| \\ | / \n");
1596 static void print_func_help_header(struct seq_file
*m
)
1598 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1599 seq_puts(m
, "# | | | | |\n");
1604 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
1606 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1607 struct trace_array
*tr
= iter
->tr
;
1608 struct trace_array_cpu
*data
= tr
->data
[tr
->cpu
];
1609 struct tracer
*type
= current_trace
;
1610 unsigned long total
;
1611 unsigned long entries
;
1612 const char *name
= "preemption";
1617 entries
= ring_buffer_entries(iter
->tr
->buffer
);
1619 ring_buffer_overruns(iter
->tr
->buffer
);
1621 seq_printf(m
, "# %s latency trace v1.1.5 on %s\n",
1623 seq_puts(m
, "# -----------------------------------"
1624 "---------------------------------\n");
1625 seq_printf(m
, "# latency: %lu us, #%lu/%lu, CPU#%d |"
1626 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1627 nsecs_to_usecs(data
->saved_latency
),
1631 #if defined(CONFIG_PREEMPT_NONE)
1633 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1635 #elif defined(CONFIG_PREEMPT)
1640 /* These are reserved for later use */
1643 seq_printf(m
, " #P:%d)\n", num_online_cpus());
1647 seq_puts(m
, "# -----------------\n");
1648 seq_printf(m
, "# | task: %.16s-%d "
1649 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1650 data
->comm
, data
->pid
, data
->uid
, data
->nice
,
1651 data
->policy
, data
->rt_priority
);
1652 seq_puts(m
, "# -----------------\n");
1654 if (data
->critical_start
) {
1655 seq_puts(m
, "# => started at: ");
1656 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
1657 trace_print_seq(m
, &iter
->seq
);
1658 seq_puts(m
, "\n# => ended at: ");
1659 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
1660 trace_print_seq(m
, &iter
->seq
);
1667 static void test_cpu_buff_start(struct trace_iterator
*iter
)
1669 struct trace_seq
*s
= &iter
->seq
;
1671 if (!(trace_flags
& TRACE_ITER_ANNOTATE
))
1674 if (!(iter
->iter_flags
& TRACE_FILE_ANNOTATE
))
1677 if (cpumask_test_cpu(iter
->cpu
, iter
->started
))
1680 cpumask_set_cpu(iter
->cpu
, iter
->started
);
1682 /* Don't print started cpu buffer for the first entry of the trace */
1684 trace_seq_printf(s
, "##### CPU %u buffer started ####\n",
1688 static enum print_line_t
print_trace_fmt(struct trace_iterator
*iter
)
1690 struct trace_seq
*s
= &iter
->seq
;
1691 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1692 struct trace_entry
*entry
;
1693 struct trace_event
*event
;
1697 test_cpu_buff_start(iter
);
1699 event
= ftrace_find_event(entry
->type
);
1701 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1702 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
1703 if (!trace_print_lat_context(iter
))
1706 if (!trace_print_context(iter
))
1712 return event
->trace(iter
, sym_flags
);
1714 if (!trace_seq_printf(s
, "Unknown type %d\n", entry
->type
))
1717 return TRACE_TYPE_HANDLED
;
1719 return TRACE_TYPE_PARTIAL_LINE
;
1722 static enum print_line_t
print_raw_fmt(struct trace_iterator
*iter
)
1724 struct trace_seq
*s
= &iter
->seq
;
1725 struct trace_entry
*entry
;
1726 struct trace_event
*event
;
1730 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1731 if (!trace_seq_printf(s
, "%d %d %llu ",
1732 entry
->pid
, iter
->cpu
, iter
->ts
))
1736 event
= ftrace_find_event(entry
->type
);
1738 return event
->raw(iter
, 0);
1740 if (!trace_seq_printf(s
, "%d ?\n", entry
->type
))
1743 return TRACE_TYPE_HANDLED
;
1745 return TRACE_TYPE_PARTIAL_LINE
;
1748 static enum print_line_t
print_hex_fmt(struct trace_iterator
*iter
)
1750 struct trace_seq
*s
= &iter
->seq
;
1751 unsigned char newline
= '\n';
1752 struct trace_entry
*entry
;
1753 struct trace_event
*event
;
1757 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1758 SEQ_PUT_HEX_FIELD_RET(s
, entry
->pid
);
1759 SEQ_PUT_HEX_FIELD_RET(s
, iter
->cpu
);
1760 SEQ_PUT_HEX_FIELD_RET(s
, iter
->ts
);
1763 event
= ftrace_find_event(entry
->type
);
1765 enum print_line_t ret
= event
->hex(iter
, 0);
1766 if (ret
!= TRACE_TYPE_HANDLED
)
1770 SEQ_PUT_FIELD_RET(s
, newline
);
1772 return TRACE_TYPE_HANDLED
;
1775 static enum print_line_t
print_bin_fmt(struct trace_iterator
*iter
)
1777 struct trace_seq
*s
= &iter
->seq
;
1778 struct trace_entry
*entry
;
1779 struct trace_event
*event
;
1783 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1784 SEQ_PUT_FIELD_RET(s
, entry
->pid
);
1785 SEQ_PUT_FIELD_RET(s
, iter
->cpu
);
1786 SEQ_PUT_FIELD_RET(s
, iter
->ts
);
1789 event
= ftrace_find_event(entry
->type
);
1790 return event
? event
->binary(iter
, 0) : TRACE_TYPE_HANDLED
;
1793 static int trace_empty(struct trace_iterator
*iter
)
1797 /* If we are looking at one CPU buffer, only check that one */
1798 if (iter
->cpu_file
!= TRACE_PIPE_ALL_CPU
) {
1799 cpu
= iter
->cpu_file
;
1800 if (iter
->buffer_iter
[cpu
]) {
1801 if (!ring_buffer_iter_empty(iter
->buffer_iter
[cpu
]))
1804 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
1810 for_each_tracing_cpu(cpu
) {
1811 if (iter
->buffer_iter
[cpu
]) {
1812 if (!ring_buffer_iter_empty(iter
->buffer_iter
[cpu
]))
1815 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
1823 /* Called with trace_event_read_lock() held. */
1824 static enum print_line_t
print_trace_line(struct trace_iterator
*iter
)
1826 enum print_line_t ret
;
1828 if (iter
->trace
&& iter
->trace
->print_line
) {
1829 ret
= iter
->trace
->print_line(iter
);
1830 if (ret
!= TRACE_TYPE_UNHANDLED
)
1834 if (iter
->ent
->type
== TRACE_BPRINT
&&
1835 trace_flags
& TRACE_ITER_PRINTK
&&
1836 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
1837 return trace_print_bprintk_msg_only(iter
);
1839 if (iter
->ent
->type
== TRACE_PRINT
&&
1840 trace_flags
& TRACE_ITER_PRINTK
&&
1841 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
1842 return trace_print_printk_msg_only(iter
);
1844 if (trace_flags
& TRACE_ITER_BIN
)
1845 return print_bin_fmt(iter
);
1847 if (trace_flags
& TRACE_ITER_HEX
)
1848 return print_hex_fmt(iter
);
1850 if (trace_flags
& TRACE_ITER_RAW
)
1851 return print_raw_fmt(iter
);
1853 return print_trace_fmt(iter
);
1856 static int s_show(struct seq_file
*m
, void *v
)
1858 struct trace_iterator
*iter
= v
;
1860 if (iter
->ent
== NULL
) {
1862 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
1865 if (iter
->trace
&& iter
->trace
->print_header
)
1866 iter
->trace
->print_header(m
);
1867 else if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
1868 /* print nothing if the buffers are empty */
1869 if (trace_empty(iter
))
1871 print_trace_header(m
, iter
);
1872 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1873 print_lat_help_header(m
);
1875 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1876 print_func_help_header(m
);
1879 print_trace_line(iter
);
1880 trace_print_seq(m
, &iter
->seq
);
1886 static struct seq_operations tracer_seq_ops
= {
1893 static struct trace_iterator
*
1894 __tracing_open(struct inode
*inode
, struct file
*file
)
1896 long cpu_file
= (long) inode
->i_private
;
1897 void *fail_ret
= ERR_PTR(-ENOMEM
);
1898 struct trace_iterator
*iter
;
1902 if (tracing_disabled
)
1903 return ERR_PTR(-ENODEV
);
1905 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
1907 return ERR_PTR(-ENOMEM
);
1910 * We make a copy of the current tracer to avoid concurrent
1911 * changes on it while we are reading.
1913 mutex_lock(&trace_types_lock
);
1914 iter
->trace
= kzalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
1919 *iter
->trace
= *current_trace
;
1921 if (!alloc_cpumask_var(&iter
->started
, GFP_KERNEL
))
1924 cpumask_clear(iter
->started
);
1926 if (current_trace
&& current_trace
->print_max
)
1929 iter
->tr
= &global_trace
;
1931 mutex_init(&iter
->mutex
);
1932 iter
->cpu_file
= cpu_file
;
1934 /* Notify the tracer early; before we stop tracing. */
1935 if (iter
->trace
&& iter
->trace
->open
)
1936 iter
->trace
->open(iter
);
1938 /* Annotate start of buffers if we had overruns */
1939 if (ring_buffer_overruns(iter
->tr
->buffer
))
1940 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
1942 if (iter
->cpu_file
== TRACE_PIPE_ALL_CPU
) {
1943 for_each_tracing_cpu(cpu
) {
1945 iter
->buffer_iter
[cpu
] =
1946 ring_buffer_read_start(iter
->tr
->buffer
, cpu
);
1949 cpu
= iter
->cpu_file
;
1950 iter
->buffer_iter
[cpu
] =
1951 ring_buffer_read_start(iter
->tr
->buffer
, cpu
);
1954 /* TODO stop tracer */
1955 ret
= seq_open(file
, &tracer_seq_ops
);
1957 fail_ret
= ERR_PTR(ret
);
1961 m
= file
->private_data
;
1964 /* stop the trace while dumping */
1967 mutex_unlock(&trace_types_lock
);
1972 for_each_tracing_cpu(cpu
) {
1973 if (iter
->buffer_iter
[cpu
])
1974 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
1976 free_cpumask_var(iter
->started
);
1978 mutex_unlock(&trace_types_lock
);
1985 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
1987 if (tracing_disabled
)
1990 filp
->private_data
= inode
->i_private
;
1994 static int tracing_release(struct inode
*inode
, struct file
*file
)
1996 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
1997 struct trace_iterator
*iter
;
2000 if (!(file
->f_mode
& FMODE_READ
))
2005 mutex_lock(&trace_types_lock
);
2006 for_each_tracing_cpu(cpu
) {
2007 if (iter
->buffer_iter
[cpu
])
2008 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
2011 if (iter
->trace
&& iter
->trace
->close
)
2012 iter
->trace
->close(iter
);
2014 /* reenable tracing if it was previously enabled */
2016 mutex_unlock(&trace_types_lock
);
2018 seq_release(inode
, file
);
2019 mutex_destroy(&iter
->mutex
);
2020 free_cpumask_var(iter
->started
);
2026 static int tracing_open(struct inode
*inode
, struct file
*file
)
2028 struct trace_iterator
*iter
;
2031 /* If this file was open for write, then erase contents */
2032 if ((file
->f_mode
& FMODE_WRITE
) &&
2033 !(file
->f_flags
& O_APPEND
)) {
2034 long cpu
= (long) inode
->i_private
;
2036 if (cpu
== TRACE_PIPE_ALL_CPU
)
2037 tracing_reset_online_cpus(&global_trace
);
2039 tracing_reset(&global_trace
, cpu
);
2042 if (file
->f_mode
& FMODE_READ
) {
2043 iter
= __tracing_open(inode
, file
);
2045 ret
= PTR_ERR(iter
);
2046 else if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
2047 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
2053 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
2055 struct tracer
*t
= v
;
2065 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
2070 mutex_lock(&trace_types_lock
);
2071 for (t
= trace_types
; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
2077 static void t_stop(struct seq_file
*m
, void *p
)
2079 mutex_unlock(&trace_types_lock
);
2082 static int t_show(struct seq_file
*m
, void *v
)
2084 struct tracer
*t
= v
;
2089 seq_printf(m
, "%s", t
->name
);
2098 static struct seq_operations show_traces_seq_ops
= {
2105 static int show_traces_open(struct inode
*inode
, struct file
*file
)
2107 if (tracing_disabled
)
2110 return seq_open(file
, &show_traces_seq_ops
);
2114 tracing_write_stub(struct file
*filp
, const char __user
*ubuf
,
2115 size_t count
, loff_t
*ppos
)
2120 static const struct file_operations tracing_fops
= {
2121 .open
= tracing_open
,
2123 .write
= tracing_write_stub
,
2124 .llseek
= seq_lseek
,
2125 .release
= tracing_release
,
2128 static const struct file_operations show_traces_fops
= {
2129 .open
= show_traces_open
,
2131 .release
= seq_release
,
2135 * Only trace on a CPU if the bitmask is set:
2137 static cpumask_var_t tracing_cpumask
;
2140 * The tracer itself will not take this lock, but still we want
2141 * to provide a consistent cpumask to user-space:
2143 static DEFINE_MUTEX(tracing_cpumask_update_lock
);
2146 * Temporary storage for the character representation of the
2147 * CPU bitmask (and one more byte for the newline):
2149 static char mask_str
[NR_CPUS
+ 1];
2152 tracing_cpumask_read(struct file
*filp
, char __user
*ubuf
,
2153 size_t count
, loff_t
*ppos
)
2157 mutex_lock(&tracing_cpumask_update_lock
);
2159 len
= cpumask_scnprintf(mask_str
, count
, tracing_cpumask
);
2160 if (count
- len
< 2) {
2164 len
+= sprintf(mask_str
+ len
, "\n");
2165 count
= simple_read_from_buffer(ubuf
, count
, ppos
, mask_str
, NR_CPUS
+1);
2168 mutex_unlock(&tracing_cpumask_update_lock
);
2174 tracing_cpumask_write(struct file
*filp
, const char __user
*ubuf
,
2175 size_t count
, loff_t
*ppos
)
2178 cpumask_var_t tracing_cpumask_new
;
2180 if (!alloc_cpumask_var(&tracing_cpumask_new
, GFP_KERNEL
))
2183 err
= cpumask_parse_user(ubuf
, count
, tracing_cpumask_new
);
2187 mutex_lock(&tracing_cpumask_update_lock
);
2189 local_irq_disable();
2190 __raw_spin_lock(&ftrace_max_lock
);
2191 for_each_tracing_cpu(cpu
) {
2193 * Increase/decrease the disabled counter if we are
2194 * about to flip a bit in the cpumask:
2196 if (cpumask_test_cpu(cpu
, tracing_cpumask
) &&
2197 !cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
2198 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
2200 if (!cpumask_test_cpu(cpu
, tracing_cpumask
) &&
2201 cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
2202 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
2205 __raw_spin_unlock(&ftrace_max_lock
);
2208 cpumask_copy(tracing_cpumask
, tracing_cpumask_new
);
2210 mutex_unlock(&tracing_cpumask_update_lock
);
2211 free_cpumask_var(tracing_cpumask_new
);
2216 free_cpumask_var(tracing_cpumask_new
);
2221 static const struct file_operations tracing_cpumask_fops
= {
2222 .open
= tracing_open_generic
,
2223 .read
= tracing_cpumask_read
,
2224 .write
= tracing_cpumask_write
,
2228 tracing_trace_options_read(struct file
*filp
, char __user
*ubuf
,
2229 size_t cnt
, loff_t
*ppos
)
2231 struct tracer_opt
*trace_opts
;
2239 /* calculate max size */
2240 for (i
= 0; trace_options
[i
]; i
++) {
2241 len
+= strlen(trace_options
[i
]);
2242 len
+= 3; /* "no" and newline */
2245 mutex_lock(&trace_types_lock
);
2246 tracer_flags
= current_trace
->flags
->val
;
2247 trace_opts
= current_trace
->flags
->opts
;
2250 * Increase the size with names of options specific
2251 * of the current tracer.
2253 for (i
= 0; trace_opts
[i
].name
; i
++) {
2254 len
+= strlen(trace_opts
[i
].name
);
2255 len
+= 3; /* "no" and newline */
2258 /* +2 for \n and \0 */
2259 buf
= kmalloc(len
+ 2, GFP_KERNEL
);
2261 mutex_unlock(&trace_types_lock
);
2265 for (i
= 0; trace_options
[i
]; i
++) {
2266 if (trace_flags
& (1 << i
))
2267 r
+= sprintf(buf
+ r
, "%s\n", trace_options
[i
]);
2269 r
+= sprintf(buf
+ r
, "no%s\n", trace_options
[i
]);
2272 for (i
= 0; trace_opts
[i
].name
; i
++) {
2273 if (tracer_flags
& trace_opts
[i
].bit
)
2274 r
+= sprintf(buf
+ r
, "%s\n",
2275 trace_opts
[i
].name
);
2277 r
+= sprintf(buf
+ r
, "no%s\n",
2278 trace_opts
[i
].name
);
2280 mutex_unlock(&trace_types_lock
);
2282 WARN_ON(r
>= len
+ 2);
2284 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2290 /* Try to assign a tracer specific option */
2291 static int set_tracer_option(struct tracer
*trace
, char *cmp
, int neg
)
2293 struct tracer_flags
*trace_flags
= trace
->flags
;
2294 struct tracer_opt
*opts
= NULL
;
2298 for (i
= 0; trace_flags
->opts
[i
].name
; i
++) {
2299 opts
= &trace_flags
->opts
[i
];
2300 len
= strlen(opts
->name
);
2302 if (strncmp(cmp
, opts
->name
, len
) == 0) {
2303 ret
= trace
->set_flag(trace_flags
->val
,
2309 if (!trace_flags
->opts
[i
].name
)
2312 /* Refused to handle */
2317 trace_flags
->val
&= ~opts
->bit
;
2319 trace_flags
->val
|= opts
->bit
;
2324 static void set_tracer_flags(unsigned int mask
, int enabled
)
2326 /* do nothing if flag is already set */
2327 if (!!(trace_flags
& mask
) == !!enabled
)
2331 trace_flags
|= mask
;
2333 trace_flags
&= ~mask
;
2335 if (mask
== TRACE_ITER_GLOBAL_CLK
) {
2339 func
= trace_clock_global
;
2341 func
= trace_clock_local
;
2343 mutex_lock(&trace_types_lock
);
2344 ring_buffer_set_clock(global_trace
.buffer
, func
);
2347 ring_buffer_set_clock(max_tr
.buffer
, func
);
2348 mutex_unlock(&trace_types_lock
);
2353 tracing_trace_options_write(struct file
*filp
, const char __user
*ubuf
,
2354 size_t cnt
, loff_t
*ppos
)
2362 if (cnt
>= sizeof(buf
))
2365 if (copy_from_user(&buf
, ubuf
, cnt
))
2370 if (strncmp(buf
, "no", 2) == 0) {
2375 for (i
= 0; trace_options
[i
]; i
++) {
2376 int len
= strlen(trace_options
[i
]);
2378 if (strncmp(cmp
, trace_options
[i
], len
) == 0) {
2379 set_tracer_flags(1 << i
, !neg
);
2384 /* If no option could be set, test the specific tracer options */
2385 if (!trace_options
[i
]) {
2386 mutex_lock(&trace_types_lock
);
2387 ret
= set_tracer_option(current_trace
, cmp
, neg
);
2388 mutex_unlock(&trace_types_lock
);
2398 static const struct file_operations tracing_iter_fops
= {
2399 .open
= tracing_open_generic
,
2400 .read
= tracing_trace_options_read
,
2401 .write
= tracing_trace_options_write
,
2404 static const char readme_msg
[] =
2405 "tracing mini-HOWTO:\n\n"
2406 "# mount -t debugfs nodev /sys/kernel/debug\n\n"
2407 "# cat /sys/kernel/debug/tracing/available_tracers\n"
2408 "wakeup preemptirqsoff preemptoff irqsoff function sched_switch nop\n\n"
2409 "# cat /sys/kernel/debug/tracing/current_tracer\n"
2411 "# echo sched_switch > /sys/kernel/debug/tracing/current_tracer\n"
2412 "# cat /sys/kernel/debug/tracing/current_tracer\n"
2414 "# cat /sys/kernel/debug/tracing/trace_options\n"
2415 "noprint-parent nosym-offset nosym-addr noverbose\n"
2416 "# echo print-parent > /sys/kernel/debug/tracing/trace_options\n"
2417 "# echo 1 > /sys/kernel/debug/tracing/tracing_enabled\n"
2418 "# cat /sys/kernel/debug/tracing/trace > /tmp/trace.txt\n"
2419 "# echo 0 > /sys/kernel/debug/tracing/tracing_enabled\n"
2423 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
2424 size_t cnt
, loff_t
*ppos
)
2426 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
2427 readme_msg
, strlen(readme_msg
));
2430 static const struct file_operations tracing_readme_fops
= {
2431 .open
= tracing_open_generic
,
2432 .read
= tracing_readme_read
,
2436 tracing_saved_cmdlines_read(struct file
*file
, char __user
*ubuf
,
2437 size_t cnt
, loff_t
*ppos
)
2446 file_buf
= kmalloc(SAVED_CMDLINES
*(16+TASK_COMM_LEN
), GFP_KERNEL
);
2450 buf_comm
= kmalloc(TASK_COMM_LEN
, GFP_KERNEL
);
2458 for (i
= 0; i
< SAVED_CMDLINES
; i
++) {
2461 pid
= map_cmdline_to_pid
[i
];
2462 if (pid
== -1 || pid
== NO_CMDLINE_MAP
)
2465 trace_find_cmdline(pid
, buf_comm
);
2466 r
= sprintf(buf
, "%d %s\n", pid
, buf_comm
);
2471 len
= simple_read_from_buffer(ubuf
, cnt
, ppos
,
2480 static const struct file_operations tracing_saved_cmdlines_fops
= {
2481 .open
= tracing_open_generic
,
2482 .read
= tracing_saved_cmdlines_read
,
2486 tracing_ctrl_read(struct file
*filp
, char __user
*ubuf
,
2487 size_t cnt
, loff_t
*ppos
)
2492 r
= sprintf(buf
, "%u\n", tracer_enabled
);
2493 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2497 tracing_ctrl_write(struct file
*filp
, const char __user
*ubuf
,
2498 size_t cnt
, loff_t
*ppos
)
2500 struct trace_array
*tr
= filp
->private_data
;
2505 if (cnt
>= sizeof(buf
))
2508 if (copy_from_user(&buf
, ubuf
, cnt
))
2513 ret
= strict_strtoul(buf
, 10, &val
);
2519 mutex_lock(&trace_types_lock
);
2520 if (tracer_enabled
^ val
) {
2523 if (current_trace
->start
)
2524 current_trace
->start(tr
);
2529 if (current_trace
->stop
)
2530 current_trace
->stop(tr
);
2533 mutex_unlock(&trace_types_lock
);
2541 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
2542 size_t cnt
, loff_t
*ppos
)
2544 char buf
[max_tracer_type_len
+2];
2547 mutex_lock(&trace_types_lock
);
2549 r
= sprintf(buf
, "%s\n", current_trace
->name
);
2551 r
= sprintf(buf
, "\n");
2552 mutex_unlock(&trace_types_lock
);
2554 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2557 int tracer_init(struct tracer
*t
, struct trace_array
*tr
)
2559 tracing_reset_online_cpus(tr
);
2563 static int tracing_resize_ring_buffer(unsigned long size
)
2568 * If kernel or user changes the size of the ring buffer
2569 * we use the size that was given, and we can forget about
2570 * expanding it later.
2572 ring_buffer_expanded
= 1;
2574 ret
= ring_buffer_resize(global_trace
.buffer
, size
);
2578 ret
= ring_buffer_resize(max_tr
.buffer
, size
);
2582 r
= ring_buffer_resize(global_trace
.buffer
,
2583 global_trace
.entries
);
2586 * AARGH! We are left with different
2587 * size max buffer!!!!
2588 * The max buffer is our "snapshot" buffer.
2589 * When a tracer needs a snapshot (one of the
2590 * latency tracers), it swaps the max buffer
2591 * with the saved snap shot. We succeeded to
2592 * update the size of the main buffer, but failed to
2593 * update the size of the max buffer. But when we tried
2594 * to reset the main buffer to the original size, we
2595 * failed there too. This is very unlikely to
2596 * happen, but if it does, warn and kill all
2600 tracing_disabled
= 1;
2605 global_trace
.entries
= size
;
2611 * tracing_update_buffers - used by tracing facility to expand ring buffers
2613 * To save on memory when the tracing is never used on a system with it
2614 * configured in. The ring buffers are set to a minimum size. But once
2615 * a user starts to use the tracing facility, then they need to grow
2616 * to their default size.
2618 * This function is to be called when a tracer is about to be used.
2620 int tracing_update_buffers(void)
2624 mutex_lock(&trace_types_lock
);
2625 if (!ring_buffer_expanded
)
2626 ret
= tracing_resize_ring_buffer(trace_buf_size
);
2627 mutex_unlock(&trace_types_lock
);
2632 struct trace_option_dentry
;
2634 static struct trace_option_dentry
*
2635 create_trace_option_files(struct tracer
*tracer
);
2638 destroy_trace_option_files(struct trace_option_dentry
*topts
);
2640 static int tracing_set_tracer(const char *buf
)
2642 static struct trace_option_dentry
*topts
;
2643 struct trace_array
*tr
= &global_trace
;
2647 mutex_lock(&trace_types_lock
);
2649 if (!ring_buffer_expanded
) {
2650 ret
= tracing_resize_ring_buffer(trace_buf_size
);
2656 for (t
= trace_types
; t
; t
= t
->next
) {
2657 if (strcmp(t
->name
, buf
) == 0)
2664 if (t
== current_trace
)
2667 trace_branch_disable();
2668 if (current_trace
&& current_trace
->reset
)
2669 current_trace
->reset(tr
);
2671 destroy_trace_option_files(topts
);
2675 topts
= create_trace_option_files(current_trace
);
2678 ret
= tracer_init(t
, tr
);
2683 trace_branch_enable(tr
);
2685 mutex_unlock(&trace_types_lock
);
2691 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
2692 size_t cnt
, loff_t
*ppos
)
2694 char buf
[max_tracer_type_len
+1];
2701 if (cnt
> max_tracer_type_len
)
2702 cnt
= max_tracer_type_len
;
2704 if (copy_from_user(&buf
, ubuf
, cnt
))
2709 /* strip ending whitespace. */
2710 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
2713 err
= tracing_set_tracer(buf
);
2723 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
2724 size_t cnt
, loff_t
*ppos
)
2726 unsigned long *ptr
= filp
->private_data
;
2730 r
= snprintf(buf
, sizeof(buf
), "%ld\n",
2731 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
2732 if (r
> sizeof(buf
))
2734 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2738 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
2739 size_t cnt
, loff_t
*ppos
)
2741 unsigned long *ptr
= filp
->private_data
;
2746 if (cnt
>= sizeof(buf
))
2749 if (copy_from_user(&buf
, ubuf
, cnt
))
2754 ret
= strict_strtoul(buf
, 10, &val
);
2763 static int tracing_open_pipe(struct inode
*inode
, struct file
*filp
)
2765 long cpu_file
= (long) inode
->i_private
;
2766 struct trace_iterator
*iter
;
2769 if (tracing_disabled
)
2772 mutex_lock(&trace_types_lock
);
2774 /* We only allow one reader per cpu */
2775 if (cpu_file
== TRACE_PIPE_ALL_CPU
) {
2776 if (!cpumask_empty(tracing_reader_cpumask
)) {
2780 cpumask_setall(tracing_reader_cpumask
);
2782 if (!cpumask_test_cpu(cpu_file
, tracing_reader_cpumask
))
2783 cpumask_set_cpu(cpu_file
, tracing_reader_cpumask
);
2790 /* create a buffer to store the information to pass to userspace */
2791 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2798 * We make a copy of the current tracer to avoid concurrent
2799 * changes on it while we are reading.
2801 iter
->trace
= kmalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
2807 *iter
->trace
= *current_trace
;
2809 if (!alloc_cpumask_var(&iter
->started
, GFP_KERNEL
)) {
2814 /* trace pipe does not show start of buffer */
2815 cpumask_setall(iter
->started
);
2817 if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
2818 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
2820 iter
->cpu_file
= cpu_file
;
2821 iter
->tr
= &global_trace
;
2822 mutex_init(&iter
->mutex
);
2823 filp
->private_data
= iter
;
2825 if (iter
->trace
->pipe_open
)
2826 iter
->trace
->pipe_open(iter
);
2829 mutex_unlock(&trace_types_lock
);
2835 mutex_unlock(&trace_types_lock
);
2839 static int tracing_release_pipe(struct inode
*inode
, struct file
*file
)
2841 struct trace_iterator
*iter
= file
->private_data
;
2843 mutex_lock(&trace_types_lock
);
2845 if (iter
->cpu_file
== TRACE_PIPE_ALL_CPU
)
2846 cpumask_clear(tracing_reader_cpumask
);
2848 cpumask_clear_cpu(iter
->cpu_file
, tracing_reader_cpumask
);
2850 mutex_unlock(&trace_types_lock
);
2852 free_cpumask_var(iter
->started
);
2853 mutex_destroy(&iter
->mutex
);
2861 tracing_poll_pipe(struct file
*filp
, poll_table
*poll_table
)
2863 struct trace_iterator
*iter
= filp
->private_data
;
2865 if (trace_flags
& TRACE_ITER_BLOCK
) {
2867 * Always select as readable when in blocking mode
2869 return POLLIN
| POLLRDNORM
;
2871 if (!trace_empty(iter
))
2872 return POLLIN
| POLLRDNORM
;
2873 poll_wait(filp
, &trace_wait
, poll_table
);
2874 if (!trace_empty(iter
))
2875 return POLLIN
| POLLRDNORM
;
2882 void default_wait_pipe(struct trace_iterator
*iter
)
2886 prepare_to_wait(&trace_wait
, &wait
, TASK_INTERRUPTIBLE
);
2888 if (trace_empty(iter
))
2891 finish_wait(&trace_wait
, &wait
);
2895 * This is a make-shift waitqueue.
2896 * A tracer might use this callback on some rare cases:
2898 * 1) the current tracer might hold the runqueue lock when it wakes up
2899 * a reader, hence a deadlock (sched, function, and function graph tracers)
2900 * 2) the function tracers, trace all functions, we don't want
2901 * the overhead of calling wake_up and friends
2902 * (and tracing them too)
2904 * Anyway, this is really very primitive wakeup.
2906 void poll_wait_pipe(struct trace_iterator
*iter
)
2908 set_current_state(TASK_INTERRUPTIBLE
);
2909 /* sleep for 100 msecs, and try again. */
2910 schedule_timeout(HZ
/ 10);
2913 /* Must be called with trace_types_lock mutex held. */
2914 static int tracing_wait_pipe(struct file
*filp
)
2916 struct trace_iterator
*iter
= filp
->private_data
;
2918 while (trace_empty(iter
)) {
2920 if ((filp
->f_flags
& O_NONBLOCK
)) {
2924 mutex_unlock(&iter
->mutex
);
2926 iter
->trace
->wait_pipe(iter
);
2928 mutex_lock(&iter
->mutex
);
2930 if (signal_pending(current
))
2934 * We block until we read something and tracing is disabled.
2935 * We still block if tracing is disabled, but we have never
2936 * read anything. This allows a user to cat this file, and
2937 * then enable tracing. But after we have read something,
2938 * we give an EOF when tracing is again disabled.
2940 * iter->pos will be 0 if we haven't read anything.
2942 if (!tracer_enabled
&& iter
->pos
)
2953 tracing_read_pipe(struct file
*filp
, char __user
*ubuf
,
2954 size_t cnt
, loff_t
*ppos
)
2956 struct trace_iterator
*iter
= filp
->private_data
;
2957 static struct tracer
*old_tracer
;
2960 /* return any leftover data */
2961 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
2965 trace_seq_init(&iter
->seq
);
2967 /* copy the tracer to avoid using a global lock all around */
2968 mutex_lock(&trace_types_lock
);
2969 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
2970 old_tracer
= current_trace
;
2971 *iter
->trace
= *current_trace
;
2973 mutex_unlock(&trace_types_lock
);
2976 * Avoid more than one consumer on a single file descriptor
2977 * This is just a matter of traces coherency, the ring buffer itself
2980 mutex_lock(&iter
->mutex
);
2981 if (iter
->trace
->read
) {
2982 sret
= iter
->trace
->read(iter
, filp
, ubuf
, cnt
, ppos
);
2988 sret
= tracing_wait_pipe(filp
);
2992 /* stop when tracing is finished */
2993 if (trace_empty(iter
)) {
2998 if (cnt
>= PAGE_SIZE
)
2999 cnt
= PAGE_SIZE
- 1;
3001 /* reset all but tr, trace, and overruns */
3002 memset(&iter
->seq
, 0,
3003 sizeof(struct trace_iterator
) -
3004 offsetof(struct trace_iterator
, seq
));
3007 trace_event_read_lock();
3008 while (find_next_entry_inc(iter
) != NULL
) {
3009 enum print_line_t ret
;
3010 int len
= iter
->seq
.len
;
3012 ret
= print_trace_line(iter
);
3013 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
3014 /* don't print partial lines */
3015 iter
->seq
.len
= len
;
3018 if (ret
!= TRACE_TYPE_NO_CONSUME
)
3019 trace_consume(iter
);
3021 if (iter
->seq
.len
>= cnt
)
3024 trace_event_read_unlock();
3026 /* Now copy what we have to the user */
3027 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
3028 if (iter
->seq
.readpos
>= iter
->seq
.len
)
3029 trace_seq_init(&iter
->seq
);
3032 * If there was nothing to send to user, inspite of consuming trace
3033 * entries, go back to wait for more entries.
3039 mutex_unlock(&iter
->mutex
);
3044 static void tracing_pipe_buf_release(struct pipe_inode_info
*pipe
,
3045 struct pipe_buffer
*buf
)
3047 __free_page(buf
->page
);
3050 static void tracing_spd_release_pipe(struct splice_pipe_desc
*spd
,
3053 __free_page(spd
->pages
[idx
]);
3056 static struct pipe_buf_operations tracing_pipe_buf_ops
= {
3058 .map
= generic_pipe_buf_map
,
3059 .unmap
= generic_pipe_buf_unmap
,
3060 .confirm
= generic_pipe_buf_confirm
,
3061 .release
= tracing_pipe_buf_release
,
3062 .steal
= generic_pipe_buf_steal
,
3063 .get
= generic_pipe_buf_get
,
3067 tracing_fill_pipe_page(size_t rem
, struct trace_iterator
*iter
)
3072 /* Seq buffer is page-sized, exactly what we need. */
3074 count
= iter
->seq
.len
;
3075 ret
= print_trace_line(iter
);
3076 count
= iter
->seq
.len
- count
;
3079 iter
->seq
.len
-= count
;
3082 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
3083 iter
->seq
.len
-= count
;
3087 trace_consume(iter
);
3089 if (!find_next_entry_inc(iter
)) {
3099 static ssize_t
tracing_splice_read_pipe(struct file
*filp
,
3101 struct pipe_inode_info
*pipe
,
3105 struct page
*pages
[PIPE_BUFFERS
];
3106 struct partial_page partial
[PIPE_BUFFERS
];
3107 struct trace_iterator
*iter
= filp
->private_data
;
3108 struct splice_pipe_desc spd
= {
3111 .nr_pages
= 0, /* This gets updated below. */
3113 .ops
= &tracing_pipe_buf_ops
,
3114 .spd_release
= tracing_spd_release_pipe
,
3116 static struct tracer
*old_tracer
;
3121 /* copy the tracer to avoid using a global lock all around */
3122 mutex_lock(&trace_types_lock
);
3123 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
3124 old_tracer
= current_trace
;
3125 *iter
->trace
= *current_trace
;
3127 mutex_unlock(&trace_types_lock
);
3129 mutex_lock(&iter
->mutex
);
3131 if (iter
->trace
->splice_read
) {
3132 ret
= iter
->trace
->splice_read(iter
, filp
,
3133 ppos
, pipe
, len
, flags
);
3138 ret
= tracing_wait_pipe(filp
);
3142 if (!iter
->ent
&& !find_next_entry_inc(iter
)) {
3147 trace_event_read_lock();
3149 /* Fill as many pages as possible. */
3150 for (i
= 0, rem
= len
; i
< PIPE_BUFFERS
&& rem
; i
++) {
3151 pages
[i
] = alloc_page(GFP_KERNEL
);
3155 rem
= tracing_fill_pipe_page(rem
, iter
);
3157 /* Copy the data into the page, so we can start over. */
3158 ret
= trace_seq_to_buffer(&iter
->seq
,
3159 page_address(pages
[i
]),
3162 __free_page(pages
[i
]);
3165 partial
[i
].offset
= 0;
3166 partial
[i
].len
= iter
->seq
.len
;
3168 trace_seq_init(&iter
->seq
);
3171 trace_event_read_unlock();
3172 mutex_unlock(&iter
->mutex
);
3176 return splice_to_pipe(pipe
, &spd
);
3179 mutex_unlock(&iter
->mutex
);
3185 tracing_entries_read(struct file
*filp
, char __user
*ubuf
,
3186 size_t cnt
, loff_t
*ppos
)
3188 struct trace_array
*tr
= filp
->private_data
;
3192 mutex_lock(&trace_types_lock
);
3193 if (!ring_buffer_expanded
)
3194 r
= sprintf(buf
, "%lu (expanded: %lu)\n",
3196 trace_buf_size
>> 10);
3198 r
= sprintf(buf
, "%lu\n", tr
->entries
>> 10);
3199 mutex_unlock(&trace_types_lock
);
3201 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3205 tracing_entries_write(struct file
*filp
, const char __user
*ubuf
,
3206 size_t cnt
, loff_t
*ppos
)
3212 if (cnt
>= sizeof(buf
))
3215 if (copy_from_user(&buf
, ubuf
, cnt
))
3220 ret
= strict_strtoul(buf
, 10, &val
);
3224 /* must have at least 1 entry */
3228 mutex_lock(&trace_types_lock
);
3232 /* disable all cpu buffers */
3233 for_each_tracing_cpu(cpu
) {
3234 if (global_trace
.data
[cpu
])
3235 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
3236 if (max_tr
.data
[cpu
])
3237 atomic_inc(&max_tr
.data
[cpu
]->disabled
);
3240 /* value is in KB */
3243 if (val
!= global_trace
.entries
) {
3244 ret
= tracing_resize_ring_buffer(val
);
3253 /* If check pages failed, return ENOMEM */
3254 if (tracing_disabled
)
3257 for_each_tracing_cpu(cpu
) {
3258 if (global_trace
.data
[cpu
])
3259 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
3260 if (max_tr
.data
[cpu
])
3261 atomic_dec(&max_tr
.data
[cpu
]->disabled
);
3265 max_tr
.entries
= global_trace
.entries
;
3266 mutex_unlock(&trace_types_lock
);
3271 static int mark_printk(const char *fmt
, ...)
3275 va_start(args
, fmt
);
3276 ret
= trace_vprintk(0, fmt
, args
);
3282 tracing_mark_write(struct file
*filp
, const char __user
*ubuf
,
3283 size_t cnt
, loff_t
*fpos
)
3288 if (tracing_disabled
)
3291 if (cnt
> TRACE_BUF_SIZE
)
3292 cnt
= TRACE_BUF_SIZE
;
3294 buf
= kmalloc(cnt
+ 1, GFP_KERNEL
);
3298 if (copy_from_user(buf
, ubuf
, cnt
)) {
3303 /* Cut from the first nil or newline. */
3305 end
= strchr(buf
, '\n');
3309 cnt
= mark_printk("%s\n", buf
);
3316 static const struct file_operations tracing_max_lat_fops
= {
3317 .open
= tracing_open_generic
,
3318 .read
= tracing_max_lat_read
,
3319 .write
= tracing_max_lat_write
,
3322 static const struct file_operations tracing_ctrl_fops
= {
3323 .open
= tracing_open_generic
,
3324 .read
= tracing_ctrl_read
,
3325 .write
= tracing_ctrl_write
,
3328 static const struct file_operations set_tracer_fops
= {
3329 .open
= tracing_open_generic
,
3330 .read
= tracing_set_trace_read
,
3331 .write
= tracing_set_trace_write
,
3334 static const struct file_operations tracing_pipe_fops
= {
3335 .open
= tracing_open_pipe
,
3336 .poll
= tracing_poll_pipe
,
3337 .read
= tracing_read_pipe
,
3338 .splice_read
= tracing_splice_read_pipe
,
3339 .release
= tracing_release_pipe
,
3342 static const struct file_operations tracing_entries_fops
= {
3343 .open
= tracing_open_generic
,
3344 .read
= tracing_entries_read
,
3345 .write
= tracing_entries_write
,
3348 static const struct file_operations tracing_mark_fops
= {
3349 .open
= tracing_open_generic
,
3350 .write
= tracing_mark_write
,
3353 struct ftrace_buffer_info
{
3354 struct trace_array
*tr
;
3360 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
)
3362 int cpu
= (int)(long)inode
->i_private
;
3363 struct ftrace_buffer_info
*info
;
3365 if (tracing_disabled
)
3368 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
3372 info
->tr
= &global_trace
;
3375 /* Force reading ring buffer for first read */
3376 info
->read
= (unsigned int)-1;
3378 filp
->private_data
= info
;
3380 return nonseekable_open(inode
, filp
);
3384 tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
3385 size_t count
, loff_t
*ppos
)
3387 struct ftrace_buffer_info
*info
= filp
->private_data
;
3396 info
->spare
= ring_buffer_alloc_read_page(info
->tr
->buffer
);
3400 /* Do we have previous read data to read? */
3401 if (info
->read
< PAGE_SIZE
)
3406 ret
= ring_buffer_read_page(info
->tr
->buffer
,
3413 pos
= ring_buffer_page_len(info
->spare
);
3415 if (pos
< PAGE_SIZE
)
3416 memset(info
->spare
+ pos
, 0, PAGE_SIZE
- pos
);
3419 size
= PAGE_SIZE
- info
->read
;
3423 ret
= copy_to_user(ubuf
, info
->spare
+ info
->read
, size
);
3434 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
)
3436 struct ftrace_buffer_info
*info
= file
->private_data
;
3439 ring_buffer_free_read_page(info
->tr
->buffer
, info
->spare
);
3446 struct ring_buffer
*buffer
;
3451 static void buffer_pipe_buf_release(struct pipe_inode_info
*pipe
,
3452 struct pipe_buffer
*buf
)
3454 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
3459 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
3464 static int buffer_pipe_buf_steal(struct pipe_inode_info
*pipe
,
3465 struct pipe_buffer
*buf
)
3470 static void buffer_pipe_buf_get(struct pipe_inode_info
*pipe
,
3471 struct pipe_buffer
*buf
)
3473 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
3478 /* Pipe buffer operations for a buffer. */
3479 static struct pipe_buf_operations buffer_pipe_buf_ops
= {
3481 .map
= generic_pipe_buf_map
,
3482 .unmap
= generic_pipe_buf_unmap
,
3483 .confirm
= generic_pipe_buf_confirm
,
3484 .release
= buffer_pipe_buf_release
,
3485 .steal
= buffer_pipe_buf_steal
,
3486 .get
= buffer_pipe_buf_get
,
3490 * Callback from splice_to_pipe(), if we need to release some pages
3491 * at the end of the spd in case we error'ed out in filling the pipe.
3493 static void buffer_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
3495 struct buffer_ref
*ref
=
3496 (struct buffer_ref
*)spd
->partial
[i
].private;
3501 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
3503 spd
->partial
[i
].private = 0;
3507 tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
3508 struct pipe_inode_info
*pipe
, size_t len
,
3511 struct ftrace_buffer_info
*info
= file
->private_data
;
3512 struct partial_page partial
[PIPE_BUFFERS
];
3513 struct page
*pages
[PIPE_BUFFERS
];
3514 struct splice_pipe_desc spd
= {
3518 .ops
= &buffer_pipe_buf_ops
,
3519 .spd_release
= buffer_spd_release
,
3521 struct buffer_ref
*ref
;
3522 int entries
, size
, i
;
3525 if (*ppos
& (PAGE_SIZE
- 1)) {
3526 WARN_ONCE(1, "Ftrace: previous read must page-align\n");
3530 if (len
& (PAGE_SIZE
- 1)) {
3531 WARN_ONCE(1, "Ftrace: splice_read should page-align\n");
3532 if (len
< PAGE_SIZE
)
3537 entries
= ring_buffer_entries_cpu(info
->tr
->buffer
, info
->cpu
);
3539 for (i
= 0; i
< PIPE_BUFFERS
&& len
&& entries
; i
++, len
-= PAGE_SIZE
) {
3543 ref
= kzalloc(sizeof(*ref
), GFP_KERNEL
);
3548 ref
->buffer
= info
->tr
->buffer
;
3549 ref
->page
= ring_buffer_alloc_read_page(ref
->buffer
);
3555 r
= ring_buffer_read_page(ref
->buffer
, &ref
->page
,
3558 ring_buffer_free_read_page(ref
->buffer
,
3565 * zero out any left over data, this is going to
3568 size
= ring_buffer_page_len(ref
->page
);
3569 if (size
< PAGE_SIZE
)
3570 memset(ref
->page
+ size
, 0, PAGE_SIZE
- size
);
3572 page
= virt_to_page(ref
->page
);
3574 spd
.pages
[i
] = page
;
3575 spd
.partial
[i
].len
= PAGE_SIZE
;
3576 spd
.partial
[i
].offset
= 0;
3577 spd
.partial
[i
].private = (unsigned long)ref
;
3581 entries
= ring_buffer_entries_cpu(info
->tr
->buffer
, info
->cpu
);
3586 /* did we read anything? */
3587 if (!spd
.nr_pages
) {
3588 if (flags
& SPLICE_F_NONBLOCK
)
3596 ret
= splice_to_pipe(pipe
, &spd
);
3601 static const struct file_operations tracing_buffers_fops
= {
3602 .open
= tracing_buffers_open
,
3603 .read
= tracing_buffers_read
,
3604 .release
= tracing_buffers_release
,
3605 .splice_read
= tracing_buffers_splice_read
,
3606 .llseek
= no_llseek
,
3610 tracing_stats_read(struct file
*filp
, char __user
*ubuf
,
3611 size_t count
, loff_t
*ppos
)
3613 unsigned long cpu
= (unsigned long)filp
->private_data
;
3614 struct trace_array
*tr
= &global_trace
;
3615 struct trace_seq
*s
;
3618 s
= kmalloc(sizeof(*s
), GFP_KERNEL
);
3624 cnt
= ring_buffer_entries_cpu(tr
->buffer
, cpu
);
3625 trace_seq_printf(s
, "entries: %ld\n", cnt
);
3627 cnt
= ring_buffer_overrun_cpu(tr
->buffer
, cpu
);
3628 trace_seq_printf(s
, "overrun: %ld\n", cnt
);
3630 cnt
= ring_buffer_commit_overrun_cpu(tr
->buffer
, cpu
);
3631 trace_seq_printf(s
, "commit overrun: %ld\n", cnt
);
3633 cnt
= ring_buffer_nmi_dropped_cpu(tr
->buffer
, cpu
);
3634 trace_seq_printf(s
, "nmi dropped: %ld\n", cnt
);
3636 count
= simple_read_from_buffer(ubuf
, count
, ppos
, s
->buffer
, s
->len
);
3643 static const struct file_operations tracing_stats_fops
= {
3644 .open
= tracing_open_generic
,
3645 .read
= tracing_stats_read
,
3648 #ifdef CONFIG_DYNAMIC_FTRACE
3650 int __weak
ftrace_arch_read_dyn_info(char *buf
, int size
)
3656 tracing_read_dyn_info(struct file
*filp
, char __user
*ubuf
,
3657 size_t cnt
, loff_t
*ppos
)
3659 static char ftrace_dyn_info_buffer
[1024];
3660 static DEFINE_MUTEX(dyn_info_mutex
);
3661 unsigned long *p
= filp
->private_data
;
3662 char *buf
= ftrace_dyn_info_buffer
;
3663 int size
= ARRAY_SIZE(ftrace_dyn_info_buffer
);
3666 mutex_lock(&dyn_info_mutex
);
3667 r
= sprintf(buf
, "%ld ", *p
);
3669 r
+= ftrace_arch_read_dyn_info(buf
+r
, (size
-1)-r
);
3672 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3674 mutex_unlock(&dyn_info_mutex
);
3679 static const struct file_operations tracing_dyn_info_fops
= {
3680 .open
= tracing_open_generic
,
3681 .read
= tracing_read_dyn_info
,
3685 static struct dentry
*d_tracer
;
3687 struct dentry
*tracing_init_dentry(void)
3694 if (!debugfs_initialized())
3697 d_tracer
= debugfs_create_dir("tracing", NULL
);
3699 if (!d_tracer
&& !once
) {
3701 pr_warning("Could not create debugfs directory 'tracing'\n");
3708 static struct dentry
*d_percpu
;
3710 struct dentry
*tracing_dentry_percpu(void)
3713 struct dentry
*d_tracer
;
3718 d_tracer
= tracing_init_dentry();
3723 d_percpu
= debugfs_create_dir("per_cpu", d_tracer
);
3725 if (!d_percpu
&& !once
) {
3727 pr_warning("Could not create debugfs directory 'per_cpu'\n");
3734 static void tracing_init_debugfs_percpu(long cpu
)
3736 struct dentry
*d_percpu
= tracing_dentry_percpu();
3737 struct dentry
*d_cpu
;
3738 /* strlen(cpu) + MAX(log10(cpu)) + '\0' */
3741 if (cpu
> 999 || cpu
< 0)
3744 sprintf(cpu_dir
, "cpu%ld", cpu
);
3745 d_cpu
= debugfs_create_dir(cpu_dir
, d_percpu
);
3747 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir
);
3751 /* per cpu trace_pipe */
3752 trace_create_file("trace_pipe", 0444, d_cpu
,
3753 (void *) cpu
, &tracing_pipe_fops
);
3756 trace_create_file("trace", 0644, d_cpu
,
3757 (void *) cpu
, &tracing_fops
);
3759 trace_create_file("trace_pipe_raw", 0444, d_cpu
,
3760 (void *) cpu
, &tracing_buffers_fops
);
3762 trace_create_file("stats", 0444, d_cpu
,
3763 (void *) cpu
, &tracing_stats_fops
);
3766 #ifdef CONFIG_FTRACE_SELFTEST
3767 /* Let selftest have access to static functions in this file */
3768 #include "trace_selftest.c"
3771 struct trace_option_dentry
{
3772 struct tracer_opt
*opt
;
3773 struct tracer_flags
*flags
;
3774 struct dentry
*entry
;
3778 trace_options_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
3781 struct trace_option_dentry
*topt
= filp
->private_data
;
3784 if (topt
->flags
->val
& topt
->opt
->bit
)
3789 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
3793 trace_options_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
3796 struct trace_option_dentry
*topt
= filp
->private_data
;
3801 if (cnt
>= sizeof(buf
))
3804 if (copy_from_user(&buf
, ubuf
, cnt
))
3809 ret
= strict_strtoul(buf
, 10, &val
);
3816 /* do nothing if already cleared */
3817 if (!(topt
->flags
->val
& topt
->opt
->bit
))
3820 mutex_lock(&trace_types_lock
);
3821 if (current_trace
->set_flag
)
3822 ret
= current_trace
->set_flag(topt
->flags
->val
,
3824 mutex_unlock(&trace_types_lock
);
3827 topt
->flags
->val
&= ~topt
->opt
->bit
;
3830 /* do nothing if already set */
3831 if (topt
->flags
->val
& topt
->opt
->bit
)
3834 mutex_lock(&trace_types_lock
);
3835 if (current_trace
->set_flag
)
3836 ret
= current_trace
->set_flag(topt
->flags
->val
,
3838 mutex_unlock(&trace_types_lock
);
3841 topt
->flags
->val
|= topt
->opt
->bit
;
3854 static const struct file_operations trace_options_fops
= {
3855 .open
= tracing_open_generic
,
3856 .read
= trace_options_read
,
3857 .write
= trace_options_write
,
3861 trace_options_core_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
3864 long index
= (long)filp
->private_data
;
3867 if (trace_flags
& (1 << index
))
3872 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
3876 trace_options_core_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
3879 long index
= (long)filp
->private_data
;
3884 if (cnt
>= sizeof(buf
))
3887 if (copy_from_user(&buf
, ubuf
, cnt
))
3892 ret
= strict_strtoul(buf
, 10, &val
);
3898 trace_flags
&= ~(1 << index
);
3901 trace_flags
|= 1 << index
;
3913 static const struct file_operations trace_options_core_fops
= {
3914 .open
= tracing_open_generic
,
3915 .read
= trace_options_core_read
,
3916 .write
= trace_options_core_write
,
3919 struct dentry
*trace_create_file(const char *name
,
3921 struct dentry
*parent
,
3923 const struct file_operations
*fops
)
3927 ret
= debugfs_create_file(name
, mode
, parent
, data
, fops
);
3929 pr_warning("Could not create debugfs '%s' entry\n", name
);
3935 static struct dentry
*trace_options_init_dentry(void)
3937 struct dentry
*d_tracer
;
3938 static struct dentry
*t_options
;
3943 d_tracer
= tracing_init_dentry();
3947 t_options
= debugfs_create_dir("options", d_tracer
);
3949 pr_warning("Could not create debugfs directory 'options'\n");
3957 create_trace_option_file(struct trace_option_dentry
*topt
,
3958 struct tracer_flags
*flags
,
3959 struct tracer_opt
*opt
)
3961 struct dentry
*t_options
;
3963 t_options
= trace_options_init_dentry();
3967 topt
->flags
= flags
;
3970 topt
->entry
= trace_create_file(opt
->name
, 0644, t_options
, topt
,
3971 &trace_options_fops
);
3975 static struct trace_option_dentry
*
3976 create_trace_option_files(struct tracer
*tracer
)
3978 struct trace_option_dentry
*topts
;
3979 struct tracer_flags
*flags
;
3980 struct tracer_opt
*opts
;
3986 flags
= tracer
->flags
;
3988 if (!flags
|| !flags
->opts
)
3993 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
3996 topts
= kcalloc(cnt
+ 1, sizeof(*topts
), GFP_KERNEL
);
4000 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
4001 create_trace_option_file(&topts
[cnt
], flags
,
4008 destroy_trace_option_files(struct trace_option_dentry
*topts
)
4015 for (cnt
= 0; topts
[cnt
].opt
; cnt
++) {
4016 if (topts
[cnt
].entry
)
4017 debugfs_remove(topts
[cnt
].entry
);
4023 static struct dentry
*
4024 create_trace_option_core_file(const char *option
, long index
)
4026 struct dentry
*t_options
;
4028 t_options
= trace_options_init_dentry();
4032 return trace_create_file(option
, 0644, t_options
, (void *)index
,
4033 &trace_options_core_fops
);
4036 static __init
void create_trace_options_dir(void)
4038 struct dentry
*t_options
;
4041 t_options
= trace_options_init_dentry();
4045 for (i
= 0; trace_options
[i
]; i
++)
4046 create_trace_option_core_file(trace_options
[i
], i
);
4049 static __init
int tracer_init_debugfs(void)
4051 struct dentry
*d_tracer
;
4054 d_tracer
= tracing_init_dentry();
4056 trace_create_file("tracing_enabled", 0644, d_tracer
,
4057 &global_trace
, &tracing_ctrl_fops
);
4059 trace_create_file("trace_options", 0644, d_tracer
,
4060 NULL
, &tracing_iter_fops
);
4062 trace_create_file("tracing_cpumask", 0644, d_tracer
,
4063 NULL
, &tracing_cpumask_fops
);
4065 trace_create_file("trace", 0644, d_tracer
,
4066 (void *) TRACE_PIPE_ALL_CPU
, &tracing_fops
);
4068 trace_create_file("available_tracers", 0444, d_tracer
,
4069 &global_trace
, &show_traces_fops
);
4071 trace_create_file("current_tracer", 0644, d_tracer
,
4072 &global_trace
, &set_tracer_fops
);
4074 trace_create_file("tracing_max_latency", 0644, d_tracer
,
4075 &tracing_max_latency
, &tracing_max_lat_fops
);
4077 trace_create_file("tracing_thresh", 0644, d_tracer
,
4078 &tracing_thresh
, &tracing_max_lat_fops
);
4080 trace_create_file("README", 0444, d_tracer
,
4081 NULL
, &tracing_readme_fops
);
4083 trace_create_file("trace_pipe", 0444, d_tracer
,
4084 (void *) TRACE_PIPE_ALL_CPU
, &tracing_pipe_fops
);
4086 trace_create_file("buffer_size_kb", 0644, d_tracer
,
4087 &global_trace
, &tracing_entries_fops
);
4089 trace_create_file("trace_marker", 0220, d_tracer
,
4090 NULL
, &tracing_mark_fops
);
4092 trace_create_file("saved_cmdlines", 0444, d_tracer
,
4093 NULL
, &tracing_saved_cmdlines_fops
);
4095 #ifdef CONFIG_DYNAMIC_FTRACE
4096 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
4097 &ftrace_update_tot_cnt
, &tracing_dyn_info_fops
);
4099 #ifdef CONFIG_SYSPROF_TRACER
4100 init_tracer_sysprof_debugfs(d_tracer
);
4103 create_trace_options_dir();
4105 for_each_tracing_cpu(cpu
)
4106 tracing_init_debugfs_percpu(cpu
);
4111 static int trace_panic_handler(struct notifier_block
*this,
4112 unsigned long event
, void *unused
)
4114 if (ftrace_dump_on_oops
)
4119 static struct notifier_block trace_panic_notifier
= {
4120 .notifier_call
= trace_panic_handler
,
4122 .priority
= 150 /* priority: INT_MAX >= x >= 0 */
4125 static int trace_die_handler(struct notifier_block
*self
,
4131 if (ftrace_dump_on_oops
)
4140 static struct notifier_block trace_die_notifier
= {
4141 .notifier_call
= trace_die_handler
,
4146 * printk is set to max of 1024, we really don't need it that big.
4147 * Nothing should be printing 1000 characters anyway.
4149 #define TRACE_MAX_PRINT 1000
4152 * Define here KERN_TRACE so that we have one place to modify
4153 * it if we decide to change what log level the ftrace dump
4156 #define KERN_TRACE KERN_EMERG
4159 trace_printk_seq(struct trace_seq
*s
)
4161 /* Probably should print a warning here. */
4165 /* should be zero ended, but we are paranoid. */
4166 s
->buffer
[s
->len
] = 0;
4168 printk(KERN_TRACE
"%s", s
->buffer
);
4173 static void __ftrace_dump(bool disable_tracing
)
4175 static raw_spinlock_t ftrace_dump_lock
=
4176 (raw_spinlock_t
)__RAW_SPIN_LOCK_UNLOCKED
;
4177 /* use static because iter can be a bit big for the stack */
4178 static struct trace_iterator iter
;
4179 unsigned int old_userobj
;
4180 static int dump_ran
;
4181 unsigned long flags
;
4185 local_irq_save(flags
);
4186 __raw_spin_lock(&ftrace_dump_lock
);
4194 if (disable_tracing
)
4197 for_each_tracing_cpu(cpu
) {
4198 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
4201 old_userobj
= trace_flags
& TRACE_ITER_SYM_USEROBJ
;
4203 /* don't look at user memory in panic mode */
4204 trace_flags
&= ~TRACE_ITER_SYM_USEROBJ
;
4206 printk(KERN_TRACE
"Dumping ftrace buffer:\n");
4208 /* Simulate the iterator */
4209 iter
.tr
= &global_trace
;
4210 iter
.trace
= current_trace
;
4211 iter
.cpu_file
= TRACE_PIPE_ALL_CPU
;
4214 * We need to stop all tracing on all CPUS to read the
4215 * the next buffer. This is a bit expensive, but is
4216 * not done often. We fill all what we can read,
4217 * and then release the locks again.
4220 while (!trace_empty(&iter
)) {
4223 printk(KERN_TRACE
"---------------------------------\n");
4227 /* reset all but tr, trace, and overruns */
4228 memset(&iter
.seq
, 0,
4229 sizeof(struct trace_iterator
) -
4230 offsetof(struct trace_iterator
, seq
));
4231 iter
.iter_flags
|= TRACE_FILE_LAT_FMT
;
4234 if (find_next_entry_inc(&iter
) != NULL
) {
4235 print_trace_line(&iter
);
4236 trace_consume(&iter
);
4239 trace_printk_seq(&iter
.seq
);
4243 printk(KERN_TRACE
" (ftrace buffer empty)\n");
4245 printk(KERN_TRACE
"---------------------------------\n");
4247 /* Re-enable tracing if requested */
4248 if (!disable_tracing
) {
4249 trace_flags
|= old_userobj
;
4251 for_each_tracing_cpu(cpu
) {
4252 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
4258 __raw_spin_unlock(&ftrace_dump_lock
);
4259 local_irq_restore(flags
);
4262 /* By default: disable tracing after the dump */
4263 void ftrace_dump(void)
4265 __ftrace_dump(true);
4268 __init
static int tracer_alloc_buffers(void)
4270 struct trace_array_cpu
*data
;
4275 if (!alloc_cpumask_var(&tracing_buffer_mask
, GFP_KERNEL
))
4278 if (!alloc_cpumask_var(&tracing_cpumask
, GFP_KERNEL
))
4279 goto out_free_buffer_mask
;
4281 if (!alloc_cpumask_var(&tracing_reader_cpumask
, GFP_KERNEL
))
4282 goto out_free_tracing_cpumask
;
4284 /* To save memory, keep the ring buffer size to its minimum */
4285 if (ring_buffer_expanded
)
4286 ring_buf_size
= trace_buf_size
;
4290 cpumask_copy(tracing_buffer_mask
, cpu_possible_mask
);
4291 cpumask_copy(tracing_cpumask
, cpu_all_mask
);
4292 cpumask_clear(tracing_reader_cpumask
);
4294 /* TODO: make the number of buffers hot pluggable with CPUS */
4295 global_trace
.buffer
= ring_buffer_alloc(ring_buf_size
,
4296 TRACE_BUFFER_FLAGS
);
4297 if (!global_trace
.buffer
) {
4298 printk(KERN_ERR
"tracer: failed to allocate ring buffer!\n");
4300 goto out_free_cpumask
;
4302 global_trace
.entries
= ring_buffer_size(global_trace
.buffer
);
4305 #ifdef CONFIG_TRACER_MAX_TRACE
4306 max_tr
.buffer
= ring_buffer_alloc(ring_buf_size
,
4307 TRACE_BUFFER_FLAGS
);
4308 if (!max_tr
.buffer
) {
4309 printk(KERN_ERR
"tracer: failed to allocate max ring buffer!\n");
4311 ring_buffer_free(global_trace
.buffer
);
4312 goto out_free_cpumask
;
4314 max_tr
.entries
= ring_buffer_size(max_tr
.buffer
);
4315 WARN_ON(max_tr
.entries
!= global_trace
.entries
);
4318 /* Allocate the first page for all buffers */
4319 for_each_tracing_cpu(i
) {
4320 data
= global_trace
.data
[i
] = &per_cpu(global_trace_cpu
, i
);
4321 max_tr
.data
[i
] = &per_cpu(max_data
, i
);
4324 trace_init_cmdlines();
4326 register_tracer(&nop_trace
);
4327 current_trace
= &nop_trace
;
4328 #ifdef CONFIG_BOOT_TRACER
4329 register_tracer(&boot_tracer
);
4331 /* All seems OK, enable tracing */
4332 tracing_disabled
= 0;
4334 atomic_notifier_chain_register(&panic_notifier_list
,
4335 &trace_panic_notifier
);
4337 register_die_notifier(&trace_die_notifier
);
4342 free_cpumask_var(tracing_reader_cpumask
);
4343 out_free_tracing_cpumask
:
4344 free_cpumask_var(tracing_cpumask
);
4345 out_free_buffer_mask
:
4346 free_cpumask_var(tracing_buffer_mask
);
4351 __init
static int clear_boot_tracer(void)
4354 * The default tracer at boot buffer is an init section.
4355 * This function is called in lateinit. If we did not
4356 * find the boot tracer, then clear it out, to prevent
4357 * later registration from accessing the buffer that is
4358 * about to be freed.
4360 if (!default_bootup_tracer
)
4363 printk(KERN_INFO
"ftrace bootup tracer '%s' not registered.\n",
4364 default_bootup_tracer
);
4365 default_bootup_tracer
= NULL
;
4370 early_initcall(tracer_alloc_buffers
);
4371 fs_initcall(tracer_init_debugfs
);
4372 late_initcall(clear_boot_tracer
);