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/smp_lock.h>
21 #include <linux/notifier.h>
22 #include <linux/irqflags.h>
23 #include <linux/debugfs.h>
24 #include <linux/pagemap.h>
25 #include <linux/hardirq.h>
26 #include <linux/linkage.h>
27 #include <linux/uaccess.h>
28 #include <linux/kprobes.h>
29 #include <linux/ftrace.h>
30 #include <linux/module.h>
31 #include <linux/percpu.h>
32 #include <linux/splice.h>
33 #include <linux/kdebug.h>
34 #include <linux/string.h>
35 #include <linux/ctype.h>
36 #include <linux/init.h>
37 #include <linux/poll.h>
38 #include <linux/gfp.h>
42 #include "trace_output.h"
44 #define TRACE_BUFFER_FLAGS (RB_FL_OVERWRITE)
47 * On boot up, the ring buffer is set to the minimum size, so that
48 * we do not waste memory on systems that are not using tracing.
50 int ring_buffer_expanded
;
53 * We need to change this state when a selftest is running.
54 * A selftest will lurk into the ring-buffer to count the
55 * entries inserted during the selftest although some concurrent
56 * insertions into the ring-buffer such as trace_printk could occurred
57 * at the same time, giving false positive or negative results.
59 static bool __read_mostly tracing_selftest_running
;
62 * If a tracer is running, we do not want to run SELFTEST.
64 bool __read_mostly tracing_selftest_disabled
;
66 /* For tracers that don't implement custom flags */
67 static struct tracer_opt dummy_tracer_opt
[] = {
71 static struct tracer_flags dummy_tracer_flags
= {
73 .opts
= dummy_tracer_opt
76 static int dummy_set_flag(u32 old_flags
, u32 bit
, int set
)
82 * Kill all tracing for good (never come back).
83 * It is initialized to 1 but will turn to zero if the initialization
84 * of the tracer is successful. But that is the only place that sets
87 static int tracing_disabled
= 1;
89 DEFINE_PER_CPU(local_t
, ftrace_cpu_disabled
);
91 static inline void ftrace_disable_cpu(void)
94 local_inc(&__get_cpu_var(ftrace_cpu_disabled
));
97 static inline void ftrace_enable_cpu(void)
99 local_dec(&__get_cpu_var(ftrace_cpu_disabled
));
103 static cpumask_var_t __read_mostly tracing_buffer_mask
;
105 /* Define which cpu buffers are currently read in trace_pipe */
106 static cpumask_var_t tracing_reader_cpumask
;
108 #define for_each_tracing_cpu(cpu) \
109 for_each_cpu(cpu, tracing_buffer_mask)
112 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
114 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
115 * is set, then ftrace_dump is called. This will output the contents
116 * of the ftrace buffers to the console. This is very useful for
117 * capturing traces that lead to crashes and outputing it to a
120 * It is default off, but you can enable it with either specifying
121 * "ftrace_dump_on_oops" in the kernel command line, or setting
122 * /proc/sys/kernel/ftrace_dump_on_oops to true.
124 int ftrace_dump_on_oops
;
126 static int tracing_set_tracer(const char *buf
);
128 #define BOOTUP_TRACER_SIZE 100
129 static char bootup_tracer_buf
[BOOTUP_TRACER_SIZE
] __initdata
;
130 static char *default_bootup_tracer
;
132 static int __init
set_ftrace(char *str
)
134 strncpy(bootup_tracer_buf
, str
, BOOTUP_TRACER_SIZE
);
135 default_bootup_tracer
= bootup_tracer_buf
;
136 /* We are using ftrace early, expand it */
137 ring_buffer_expanded
= 1;
140 __setup("ftrace=", set_ftrace
);
142 static int __init
set_ftrace_dump_on_oops(char *str
)
144 ftrace_dump_on_oops
= 1;
147 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops
);
149 unsigned long long ns2usecs(cycle_t nsec
)
157 * The global_trace is the descriptor that holds the tracing
158 * buffers for the live tracing. For each CPU, it contains
159 * a link list of pages that will store trace entries. The
160 * page descriptor of the pages in the memory is used to hold
161 * the link list by linking the lru item in the page descriptor
162 * to each of the pages in the buffer per CPU.
164 * For each active CPU there is a data field that holds the
165 * pages for the buffer for that CPU. Each CPU has the same number
166 * of pages allocated for its buffer.
168 static struct trace_array global_trace
;
170 static DEFINE_PER_CPU(struct trace_array_cpu
, global_trace_cpu
);
172 int filter_current_check_discard(struct ftrace_event_call
*call
, void *rec
,
173 struct ring_buffer_event
*event
)
175 return filter_check_discard(call
, rec
, global_trace
.buffer
, event
);
177 EXPORT_SYMBOL_GPL(filter_current_check_discard
);
179 cycle_t
ftrace_now(int cpu
)
183 /* Early boot up does not have a buffer yet */
184 if (!global_trace
.buffer
)
185 return trace_clock_local();
187 ts
= ring_buffer_time_stamp(global_trace
.buffer
, cpu
);
188 ring_buffer_normalize_time_stamp(global_trace
.buffer
, cpu
, &ts
);
194 * The max_tr is used to snapshot the global_trace when a maximum
195 * latency is reached. Some tracers will use this to store a maximum
196 * trace while it continues examining live traces.
198 * The buffers for the max_tr are set up the same as the global_trace.
199 * When a snapshot is taken, the link list of the max_tr is swapped
200 * with the link list of the global_trace and the buffers are reset for
201 * the global_trace so the tracing can continue.
203 static struct trace_array max_tr
;
205 static DEFINE_PER_CPU(struct trace_array_cpu
, max_data
);
207 /* tracer_enabled is used to toggle activation of a tracer */
208 static int tracer_enabled
= 1;
211 * tracing_is_enabled - return tracer_enabled status
213 * This function is used by other tracers to know the status
214 * of the tracer_enabled flag. Tracers may use this function
215 * to know if it should enable their features when starting
216 * up. See irqsoff tracer for an example (start_irqsoff_tracer).
218 int tracing_is_enabled(void)
220 return tracer_enabled
;
224 * trace_buf_size is the size in bytes that is allocated
225 * for a buffer. Note, the number of bytes is always rounded
228 * This number is purposely set to a low number of 16384.
229 * If the dump on oops happens, it will be much appreciated
230 * to not have to wait for all that output. Anyway this can be
231 * boot time and run time configurable.
233 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
235 static unsigned long trace_buf_size
= TRACE_BUF_SIZE_DEFAULT
;
237 /* trace_types holds a link list of available tracers. */
238 static struct tracer
*trace_types __read_mostly
;
240 /* current_trace points to the tracer that is currently active */
241 static struct tracer
*current_trace __read_mostly
;
244 * max_tracer_type_len is used to simplify the allocating of
245 * buffers to read userspace tracer names. We keep track of
246 * the longest tracer name registered.
248 static int max_tracer_type_len
;
251 * trace_types_lock is used to protect the trace_types list.
252 * This lock is also used to keep user access serialized.
253 * Accesses from userspace will grab this lock while userspace
254 * activities happen inside the kernel.
256 static DEFINE_MUTEX(trace_types_lock
);
258 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
259 static DECLARE_WAIT_QUEUE_HEAD(trace_wait
);
261 /* trace_flags holds trace_options default values */
262 unsigned long trace_flags
= TRACE_ITER_PRINT_PARENT
| TRACE_ITER_PRINTK
|
263 TRACE_ITER_ANNOTATE
| TRACE_ITER_CONTEXT_INFO
| TRACE_ITER_SLEEP_TIME
|
264 TRACE_ITER_GRAPH_TIME
;
266 static int trace_stop_count
;
267 static DEFINE_SPINLOCK(tracing_start_lock
);
270 * trace_wake_up - wake up tasks waiting for trace input
272 * Simply wakes up any task that is blocked on the trace_wait
273 * queue. These is used with trace_poll for tasks polling the trace.
275 void trace_wake_up(void)
278 * The runqueue_is_locked() can fail, but this is the best we
281 if (!(trace_flags
& TRACE_ITER_BLOCK
) && !runqueue_is_locked())
282 wake_up(&trace_wait
);
285 static int __init
set_buf_size(char *str
)
287 unsigned long buf_size
;
291 buf_size
= memparse(str
, &str
);
292 /* nr_entries can not be zero */
295 trace_buf_size
= buf_size
;
298 __setup("trace_buf_size=", set_buf_size
);
300 unsigned long nsecs_to_usecs(unsigned long nsecs
)
305 /* These must match the bit postions in trace_iterator_flags */
306 static const char *trace_options
[] = {
335 { trace_clock_local
, "local" },
336 { trace_clock_global
, "global" },
341 ssize_t
trace_seq_to_user(struct trace_seq
*s
, char __user
*ubuf
, size_t cnt
)
349 if (s
->len
<= s
->readpos
)
352 len
= s
->len
- s
->readpos
;
355 ret
= copy_to_user(ubuf
, s
->buffer
+ s
->readpos
, cnt
);
365 static ssize_t
trace_seq_to_buffer(struct trace_seq
*s
, void *buf
, size_t cnt
)
370 if (s
->len
<= s
->readpos
)
373 len
= s
->len
- s
->readpos
;
376 ret
= memcpy(buf
, s
->buffer
+ s
->readpos
, cnt
);
385 * ftrace_max_lock is used to protect the swapping of buffers
386 * when taking a max snapshot. The buffers themselves are
387 * protected by per_cpu spinlocks. But the action of the swap
388 * needs its own lock.
390 * This is defined as a raw_spinlock_t in order to help
391 * with performance when lockdep debugging is enabled.
393 * It is also used in other places outside the update_max_tr
394 * so it needs to be defined outside of the
395 * CONFIG_TRACER_MAX_TRACE.
397 static raw_spinlock_t ftrace_max_lock
=
398 (raw_spinlock_t
)__RAW_SPIN_LOCK_UNLOCKED
;
400 #ifdef CONFIG_TRACER_MAX_TRACE
401 unsigned long __read_mostly tracing_max_latency
;
402 unsigned long __read_mostly tracing_thresh
;
405 * Copy the new maximum trace into the separate maximum-trace
406 * structure. (this way the maximum trace is permanently saved,
407 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
410 __update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
412 struct trace_array_cpu
*data
= tr
->data
[cpu
];
413 struct trace_array_cpu
*max_data
= tr
->data
[cpu
];
416 max_tr
.time_start
= data
->preempt_timestamp
;
418 max_data
= max_tr
.data
[cpu
];
419 max_data
->saved_latency
= tracing_max_latency
;
420 max_data
->critical_start
= data
->critical_start
;
421 max_data
->critical_end
= data
->critical_end
;
423 memcpy(data
->comm
, tsk
->comm
, TASK_COMM_LEN
);
424 max_data
->pid
= tsk
->pid
;
425 max_data
->uid
= task_uid(tsk
);
426 max_data
->nice
= tsk
->static_prio
- 20 - MAX_RT_PRIO
;
427 max_data
->policy
= tsk
->policy
;
428 max_data
->rt_priority
= tsk
->rt_priority
;
430 /* record this tasks comm */
431 tracing_record_cmdline(tsk
);
435 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
437 * @tsk: the task with the latency
438 * @cpu: The cpu that initiated the trace.
440 * Flip the buffers between the @tr and the max_tr and record information
441 * about which task was the cause of this latency.
444 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
446 struct ring_buffer
*buf
= tr
->buffer
;
448 if (trace_stop_count
)
451 WARN_ON_ONCE(!irqs_disabled());
452 __raw_spin_lock(&ftrace_max_lock
);
454 tr
->buffer
= max_tr
.buffer
;
457 ftrace_disable_cpu();
458 ring_buffer_reset(tr
->buffer
);
461 __update_max_tr(tr
, tsk
, cpu
);
462 __raw_spin_unlock(&ftrace_max_lock
);
466 * update_max_tr_single - only copy one trace over, and reset the rest
468 * @tsk - task with the latency
469 * @cpu - the cpu of the buffer to copy.
471 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
474 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
478 if (trace_stop_count
)
481 WARN_ON_ONCE(!irqs_disabled());
482 __raw_spin_lock(&ftrace_max_lock
);
484 ftrace_disable_cpu();
486 ring_buffer_reset(max_tr
.buffer
);
487 ret
= ring_buffer_swap_cpu(max_tr
.buffer
, tr
->buffer
, cpu
);
491 WARN_ON_ONCE(ret
&& ret
!= -EAGAIN
);
493 __update_max_tr(tr
, tsk
, cpu
);
494 __raw_spin_unlock(&ftrace_max_lock
);
496 #endif /* CONFIG_TRACER_MAX_TRACE */
499 * register_tracer - register a tracer with the ftrace system.
500 * @type - the plugin for the tracer
502 * Register a new plugin tracer.
504 int register_tracer(struct tracer
*type
)
505 __releases(kernel_lock
)
506 __acquires(kernel_lock
)
513 pr_info("Tracer must have a name\n");
518 * When this gets called we hold the BKL which means that
519 * preemption is disabled. Various trace selftests however
520 * need to disable and enable preemption for successful tests.
521 * So we drop the BKL here and grab it after the tests again.
524 mutex_lock(&trace_types_lock
);
526 tracing_selftest_running
= true;
528 for (t
= trace_types
; t
; t
= t
->next
) {
529 if (strcmp(type
->name
, t
->name
) == 0) {
531 pr_info("Trace %s already registered\n",
539 type
->set_flag
= &dummy_set_flag
;
541 type
->flags
= &dummy_tracer_flags
;
543 if (!type
->flags
->opts
)
544 type
->flags
->opts
= dummy_tracer_opt
;
545 if (!type
->wait_pipe
)
546 type
->wait_pipe
= default_wait_pipe
;
549 #ifdef CONFIG_FTRACE_STARTUP_TEST
550 if (type
->selftest
&& !tracing_selftest_disabled
) {
551 struct tracer
*saved_tracer
= current_trace
;
552 struct trace_array
*tr
= &global_trace
;
555 * Run a selftest on this tracer.
556 * Here we reset the trace buffer, and set the current
557 * tracer to be this tracer. The tracer can then run some
558 * internal tracing to verify that everything is in order.
559 * If we fail, we do not register this tracer.
561 tracing_reset_online_cpus(tr
);
563 current_trace
= type
;
564 /* the test is responsible for initializing and enabling */
565 pr_info("Testing tracer %s: ", type
->name
);
566 ret
= type
->selftest(type
, tr
);
567 /* the test is responsible for resetting too */
568 current_trace
= saved_tracer
;
570 printk(KERN_CONT
"FAILED!\n");
573 /* Only reset on passing, to avoid touching corrupted buffers */
574 tracing_reset_online_cpus(tr
);
576 printk(KERN_CONT
"PASSED\n");
580 type
->next
= trace_types
;
582 len
= strlen(type
->name
);
583 if (len
> max_tracer_type_len
)
584 max_tracer_type_len
= len
;
587 tracing_selftest_running
= false;
588 mutex_unlock(&trace_types_lock
);
590 if (ret
|| !default_bootup_tracer
)
593 if (strncmp(default_bootup_tracer
, type
->name
, BOOTUP_TRACER_SIZE
))
596 printk(KERN_INFO
"Starting tracer '%s'\n", type
->name
);
597 /* Do we want this tracer to start on bootup? */
598 tracing_set_tracer(type
->name
);
599 default_bootup_tracer
= NULL
;
600 /* disable other selftests, since this will break it. */
601 tracing_selftest_disabled
= 1;
602 #ifdef CONFIG_FTRACE_STARTUP_TEST
603 printk(KERN_INFO
"Disabling FTRACE selftests due to running tracer '%s'\n",
612 void unregister_tracer(struct tracer
*type
)
617 mutex_lock(&trace_types_lock
);
618 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
622 pr_info("Trace %s not registered\n", type
->name
);
628 if (type
== current_trace
&& tracer_enabled
) {
631 if (current_trace
->stop
)
632 current_trace
->stop(&global_trace
);
633 current_trace
= &nop_trace
;
636 if (strlen(type
->name
) != max_tracer_type_len
)
639 max_tracer_type_len
= 0;
640 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
641 len
= strlen((*t
)->name
);
642 if (len
> max_tracer_type_len
)
643 max_tracer_type_len
= len
;
646 mutex_unlock(&trace_types_lock
);
649 void tracing_reset(struct trace_array
*tr
, int cpu
)
651 ftrace_disable_cpu();
652 ring_buffer_reset_cpu(tr
->buffer
, cpu
);
656 void tracing_reset_online_cpus(struct trace_array
*tr
)
658 struct ring_buffer
*buffer
= tr
->buffer
;
661 ring_buffer_record_disable(buffer
);
663 /* Make sure all commits have finished */
666 tr
->time_start
= ftrace_now(tr
->cpu
);
668 for_each_online_cpu(cpu
)
669 tracing_reset(tr
, cpu
);
671 ring_buffer_record_enable(buffer
);
674 void tracing_reset_current(int cpu
)
676 tracing_reset(&global_trace
, cpu
);
679 void tracing_reset_current_online_cpus(void)
681 tracing_reset_online_cpus(&global_trace
);
684 #define SAVED_CMDLINES 128
685 #define NO_CMDLINE_MAP UINT_MAX
686 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
687 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
688 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
689 static int cmdline_idx
;
690 static raw_spinlock_t trace_cmdline_lock
= __RAW_SPIN_LOCK_UNLOCKED
;
692 /* temporary disable recording */
693 static atomic_t trace_record_cmdline_disabled __read_mostly
;
695 static void trace_init_cmdlines(void)
697 memset(&map_pid_to_cmdline
, NO_CMDLINE_MAP
, sizeof(map_pid_to_cmdline
));
698 memset(&map_cmdline_to_pid
, NO_CMDLINE_MAP
, sizeof(map_cmdline_to_pid
));
703 * ftrace_off_permanent - disable all ftrace code permanently
705 * This should only be called when a serious anomally has
706 * been detected. This will turn off the function tracing,
707 * ring buffers, and other tracing utilites. It takes no
708 * locks and can be called from any context.
710 void ftrace_off_permanent(void)
712 tracing_disabled
= 1;
714 tracing_off_permanent();
718 * tracing_start - quick start of the tracer
720 * If tracing is enabled but was stopped by tracing_stop,
721 * this will start the tracer back up.
723 void tracing_start(void)
725 struct ring_buffer
*buffer
;
728 if (tracing_disabled
)
731 spin_lock_irqsave(&tracing_start_lock
, flags
);
732 if (--trace_stop_count
) {
733 if (trace_stop_count
< 0) {
734 /* Someone screwed up their debugging */
736 trace_stop_count
= 0;
742 buffer
= global_trace
.buffer
;
744 ring_buffer_record_enable(buffer
);
746 buffer
= max_tr
.buffer
;
748 ring_buffer_record_enable(buffer
);
752 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
756 * tracing_stop - quick stop of the tracer
758 * Light weight way to stop tracing. Use in conjunction with
761 void tracing_stop(void)
763 struct ring_buffer
*buffer
;
767 spin_lock_irqsave(&tracing_start_lock
, flags
);
768 if (trace_stop_count
++)
771 buffer
= global_trace
.buffer
;
773 ring_buffer_record_disable(buffer
);
775 buffer
= max_tr
.buffer
;
777 ring_buffer_record_disable(buffer
);
780 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
783 void trace_stop_cmdline_recording(void);
785 static void trace_save_cmdline(struct task_struct
*tsk
)
789 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
793 * It's not the end of the world if we don't get
794 * the lock, but we also don't want to spin
795 * nor do we want to disable interrupts,
796 * so if we miss here, then better luck next time.
798 if (!__raw_spin_trylock(&trace_cmdline_lock
))
801 idx
= map_pid_to_cmdline
[tsk
->pid
];
802 if (idx
== NO_CMDLINE_MAP
) {
803 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
806 * Check whether the cmdline buffer at idx has a pid
807 * mapped. We are going to overwrite that entry so we
808 * need to clear the map_pid_to_cmdline. Otherwise we
809 * would read the new comm for the old pid.
811 pid
= map_cmdline_to_pid
[idx
];
812 if (pid
!= NO_CMDLINE_MAP
)
813 map_pid_to_cmdline
[pid
] = NO_CMDLINE_MAP
;
815 map_cmdline_to_pid
[idx
] = tsk
->pid
;
816 map_pid_to_cmdline
[tsk
->pid
] = idx
;
821 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
823 __raw_spin_unlock(&trace_cmdline_lock
);
826 void trace_find_cmdline(int pid
, char comm
[])
831 strcpy(comm
, "<idle>");
835 if (pid
> PID_MAX_DEFAULT
) {
836 strcpy(comm
, "<...>");
841 __raw_spin_lock(&trace_cmdline_lock
);
842 map
= map_pid_to_cmdline
[pid
];
843 if (map
!= NO_CMDLINE_MAP
)
844 strcpy(comm
, saved_cmdlines
[map
]);
846 strcpy(comm
, "<...>");
848 __raw_spin_unlock(&trace_cmdline_lock
);
852 void tracing_record_cmdline(struct task_struct
*tsk
)
854 if (atomic_read(&trace_record_cmdline_disabled
) || !tracer_enabled
||
858 trace_save_cmdline(tsk
);
862 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
,
865 struct task_struct
*tsk
= current
;
867 entry
->preempt_count
= pc
& 0xff;
868 entry
->pid
= (tsk
) ? tsk
->pid
: 0;
869 entry
->tgid
= (tsk
) ? tsk
->tgid
: 0;
871 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
872 (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
874 TRACE_FLAG_IRQS_NOSUPPORT
|
876 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
877 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
878 (need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0);
880 EXPORT_SYMBOL_GPL(tracing_generic_entry_update
);
882 struct ring_buffer_event
*trace_buffer_lock_reserve(struct trace_array
*tr
,
885 unsigned long flags
, int pc
)
887 struct ring_buffer_event
*event
;
889 event
= ring_buffer_lock_reserve(tr
->buffer
, len
);
891 struct trace_entry
*ent
= ring_buffer_event_data(event
);
893 tracing_generic_entry_update(ent
, flags
, pc
);
900 static inline void __trace_buffer_unlock_commit(struct trace_array
*tr
,
901 struct ring_buffer_event
*event
,
902 unsigned long flags
, int pc
,
905 ring_buffer_unlock_commit(tr
->buffer
, event
);
907 ftrace_trace_stack(tr
, flags
, 6, pc
);
908 ftrace_trace_userstack(tr
, flags
, pc
);
914 void trace_buffer_unlock_commit(struct trace_array
*tr
,
915 struct ring_buffer_event
*event
,
916 unsigned long flags
, int pc
)
918 __trace_buffer_unlock_commit(tr
, event
, flags
, pc
, 1);
921 struct ring_buffer_event
*
922 trace_current_buffer_lock_reserve(int type
, unsigned long len
,
923 unsigned long flags
, int pc
)
925 return trace_buffer_lock_reserve(&global_trace
,
926 type
, len
, flags
, pc
);
928 EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve
);
930 void trace_current_buffer_unlock_commit(struct ring_buffer_event
*event
,
931 unsigned long flags
, int pc
)
933 __trace_buffer_unlock_commit(&global_trace
, event
, flags
, pc
, 1);
935 EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit
);
937 void trace_nowake_buffer_unlock_commit(struct ring_buffer_event
*event
,
938 unsigned long flags
, int pc
)
940 __trace_buffer_unlock_commit(&global_trace
, event
, flags
, pc
, 0);
942 EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit
);
944 void trace_current_buffer_discard_commit(struct ring_buffer_event
*event
)
946 ring_buffer_discard_commit(global_trace
.buffer
, event
);
948 EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit
);
951 trace_function(struct trace_array
*tr
,
952 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
955 struct ftrace_event_call
*call
= &event_function
;
956 struct ring_buffer_event
*event
;
957 struct ftrace_entry
*entry
;
959 /* If we are reading the ring buffer, don't trace */
960 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
963 event
= trace_buffer_lock_reserve(tr
, TRACE_FN
, sizeof(*entry
),
967 entry
= ring_buffer_event_data(event
);
969 entry
->parent_ip
= parent_ip
;
971 if (!filter_check_discard(call
, entry
, tr
->buffer
, event
))
972 ring_buffer_unlock_commit(tr
->buffer
, event
);
976 ftrace(struct trace_array
*tr
, struct trace_array_cpu
*data
,
977 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
980 if (likely(!atomic_read(&data
->disabled
)))
981 trace_function(tr
, ip
, parent_ip
, flags
, pc
);
984 #ifdef CONFIG_STACKTRACE
985 static void __ftrace_trace_stack(struct trace_array
*tr
,
989 struct ftrace_event_call
*call
= &event_kernel_stack
;
990 struct ring_buffer_event
*event
;
991 struct stack_entry
*entry
;
992 struct stack_trace trace
;
994 event
= trace_buffer_lock_reserve(tr
, TRACE_STACK
,
995 sizeof(*entry
), flags
, pc
);
998 entry
= ring_buffer_event_data(event
);
999 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
1001 trace
.nr_entries
= 0;
1002 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1004 trace
.entries
= entry
->caller
;
1006 save_stack_trace(&trace
);
1007 if (!filter_check_discard(call
, entry
, tr
->buffer
, event
))
1008 ring_buffer_unlock_commit(tr
->buffer
, event
);
1011 void ftrace_trace_stack(struct trace_array
*tr
, unsigned long flags
, int skip
,
1014 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1017 __ftrace_trace_stack(tr
, flags
, skip
, pc
);
1020 void __trace_stack(struct trace_array
*tr
, unsigned long flags
, int skip
,
1023 __ftrace_trace_stack(tr
, flags
, skip
, pc
);
1026 void ftrace_trace_userstack(struct trace_array
*tr
, unsigned long flags
, int pc
)
1028 struct ftrace_event_call
*call
= &event_user_stack
;
1029 struct ring_buffer_event
*event
;
1030 struct userstack_entry
*entry
;
1031 struct stack_trace trace
;
1033 if (!(trace_flags
& TRACE_ITER_USERSTACKTRACE
))
1036 event
= trace_buffer_lock_reserve(tr
, TRACE_USER_STACK
,
1037 sizeof(*entry
), flags
, pc
);
1040 entry
= ring_buffer_event_data(event
);
1042 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
1044 trace
.nr_entries
= 0;
1045 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1047 trace
.entries
= entry
->caller
;
1049 save_stack_trace_user(&trace
);
1050 if (!filter_check_discard(call
, entry
, tr
->buffer
, event
))
1051 ring_buffer_unlock_commit(tr
->buffer
, event
);
1055 static void __trace_userstack(struct trace_array
*tr
, unsigned long flags
)
1057 ftrace_trace_userstack(tr
, flags
, preempt_count());
1061 #endif /* CONFIG_STACKTRACE */
1064 ftrace_trace_special(void *__tr
,
1065 unsigned long arg1
, unsigned long arg2
, unsigned long arg3
,
1068 struct ring_buffer_event
*event
;
1069 struct trace_array
*tr
= __tr
;
1070 struct special_entry
*entry
;
1072 event
= trace_buffer_lock_reserve(tr
, TRACE_SPECIAL
,
1073 sizeof(*entry
), 0, pc
);
1076 entry
= ring_buffer_event_data(event
);
1080 trace_buffer_unlock_commit(tr
, event
, 0, pc
);
1084 __trace_special(void *__tr
, void *__data
,
1085 unsigned long arg1
, unsigned long arg2
, unsigned long arg3
)
1087 ftrace_trace_special(__tr
, arg1
, arg2
, arg3
, preempt_count());
1091 ftrace_special(unsigned long arg1
, unsigned long arg2
, unsigned long arg3
)
1093 struct trace_array
*tr
= &global_trace
;
1094 struct trace_array_cpu
*data
;
1095 unsigned long flags
;
1099 if (tracing_disabled
)
1102 pc
= preempt_count();
1103 local_irq_save(flags
);
1104 cpu
= raw_smp_processor_id();
1105 data
= tr
->data
[cpu
];
1107 if (likely(atomic_inc_return(&data
->disabled
) == 1))
1108 ftrace_trace_special(tr
, arg1
, arg2
, arg3
, pc
);
1110 atomic_dec(&data
->disabled
);
1111 local_irq_restore(flags
);
1115 * trace_vbprintk - write binary msg to tracing buffer
1118 int trace_vbprintk(unsigned long ip
, const char *fmt
, va_list args
)
1120 static raw_spinlock_t trace_buf_lock
=
1121 (raw_spinlock_t
)__RAW_SPIN_LOCK_UNLOCKED
;
1122 static u32 trace_buf
[TRACE_BUF_SIZE
];
1124 struct ftrace_event_call
*call
= &event_bprint
;
1125 struct ring_buffer_event
*event
;
1126 struct trace_array
*tr
= &global_trace
;
1127 struct trace_array_cpu
*data
;
1128 struct bprint_entry
*entry
;
1129 unsigned long flags
;
1132 int cpu
, len
= 0, size
, pc
;
1134 if (unlikely(tracing_selftest_running
|| tracing_disabled
))
1137 /* Don't pollute graph traces with trace_vprintk internals */
1138 pause_graph_tracing();
1140 pc
= preempt_count();
1141 resched
= ftrace_preempt_disable();
1142 cpu
= raw_smp_processor_id();
1143 data
= tr
->data
[cpu
];
1145 disable
= atomic_inc_return(&data
->disabled
);
1146 if (unlikely(disable
!= 1))
1149 /* Lockdep uses trace_printk for lock tracing */
1150 local_irq_save(flags
);
1151 __raw_spin_lock(&trace_buf_lock
);
1152 len
= vbin_printf(trace_buf
, TRACE_BUF_SIZE
, fmt
, args
);
1154 if (len
> TRACE_BUF_SIZE
|| len
< 0)
1157 size
= sizeof(*entry
) + sizeof(u32
) * len
;
1158 event
= trace_buffer_lock_reserve(tr
, TRACE_BPRINT
, size
, flags
, pc
);
1161 entry
= ring_buffer_event_data(event
);
1165 memcpy(entry
->buf
, trace_buf
, sizeof(u32
) * len
);
1166 if (!filter_check_discard(call
, entry
, tr
->buffer
, event
))
1167 ring_buffer_unlock_commit(tr
->buffer
, event
);
1170 __raw_spin_unlock(&trace_buf_lock
);
1171 local_irq_restore(flags
);
1174 atomic_dec_return(&data
->disabled
);
1175 ftrace_preempt_enable(resched
);
1176 unpause_graph_tracing();
1180 EXPORT_SYMBOL_GPL(trace_vbprintk
);
1182 int trace_vprintk(unsigned long ip
, const char *fmt
, va_list args
)
1184 static raw_spinlock_t trace_buf_lock
= __RAW_SPIN_LOCK_UNLOCKED
;
1185 static char trace_buf
[TRACE_BUF_SIZE
];
1187 struct ftrace_event_call
*call
= &event_print
;
1188 struct ring_buffer_event
*event
;
1189 struct trace_array
*tr
= &global_trace
;
1190 struct trace_array_cpu
*data
;
1191 int cpu
, len
= 0, size
, pc
;
1192 struct print_entry
*entry
;
1193 unsigned long irq_flags
;
1196 if (tracing_disabled
|| tracing_selftest_running
)
1199 pc
= preempt_count();
1200 preempt_disable_notrace();
1201 cpu
= raw_smp_processor_id();
1202 data
= tr
->data
[cpu
];
1204 disable
= atomic_inc_return(&data
->disabled
);
1205 if (unlikely(disable
!= 1))
1208 pause_graph_tracing();
1209 raw_local_irq_save(irq_flags
);
1210 __raw_spin_lock(&trace_buf_lock
);
1211 len
= vsnprintf(trace_buf
, TRACE_BUF_SIZE
, fmt
, args
);
1213 len
= min(len
, TRACE_BUF_SIZE
-1);
1216 size
= sizeof(*entry
) + len
+ 1;
1217 event
= trace_buffer_lock_reserve(tr
, TRACE_PRINT
, size
, irq_flags
, pc
);
1220 entry
= ring_buffer_event_data(event
);
1223 memcpy(&entry
->buf
, trace_buf
, len
);
1224 entry
->buf
[len
] = 0;
1225 if (!filter_check_discard(call
, entry
, tr
->buffer
, event
))
1226 ring_buffer_unlock_commit(tr
->buffer
, event
);
1229 __raw_spin_unlock(&trace_buf_lock
);
1230 raw_local_irq_restore(irq_flags
);
1231 unpause_graph_tracing();
1233 atomic_dec_return(&data
->disabled
);
1234 preempt_enable_notrace();
1238 EXPORT_SYMBOL_GPL(trace_vprintk
);
1240 enum trace_file_type
{
1241 TRACE_FILE_LAT_FMT
= 1,
1242 TRACE_FILE_ANNOTATE
= 2,
1245 static void trace_iterator_increment(struct trace_iterator
*iter
)
1247 /* Don't allow ftrace to trace into the ring buffers */
1248 ftrace_disable_cpu();
1251 if (iter
->buffer_iter
[iter
->cpu
])
1252 ring_buffer_read(iter
->buffer_iter
[iter
->cpu
], NULL
);
1254 ftrace_enable_cpu();
1257 static struct trace_entry
*
1258 peek_next_entry(struct trace_iterator
*iter
, int cpu
, u64
*ts
)
1260 struct ring_buffer_event
*event
;
1261 struct ring_buffer_iter
*buf_iter
= iter
->buffer_iter
[cpu
];
1263 /* Don't allow ftrace to trace into the ring buffers */
1264 ftrace_disable_cpu();
1267 event
= ring_buffer_iter_peek(buf_iter
, ts
);
1269 event
= ring_buffer_peek(iter
->tr
->buffer
, cpu
, ts
);
1271 ftrace_enable_cpu();
1273 return event
? ring_buffer_event_data(event
) : NULL
;
1276 static struct trace_entry
*
1277 __find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
, u64
*ent_ts
)
1279 struct ring_buffer
*buffer
= iter
->tr
->buffer
;
1280 struct trace_entry
*ent
, *next
= NULL
;
1281 int cpu_file
= iter
->cpu_file
;
1282 u64 next_ts
= 0, ts
;
1287 * If we are in a per_cpu trace file, don't bother by iterating over
1288 * all cpu and peek directly.
1290 if (cpu_file
> TRACE_PIPE_ALL_CPU
) {
1291 if (ring_buffer_empty_cpu(buffer
, cpu_file
))
1293 ent
= peek_next_entry(iter
, cpu_file
, ent_ts
);
1295 *ent_cpu
= cpu_file
;
1300 for_each_tracing_cpu(cpu
) {
1302 if (ring_buffer_empty_cpu(buffer
, cpu
))
1305 ent
= peek_next_entry(iter
, cpu
, &ts
);
1308 * Pick the entry with the smallest timestamp:
1310 if (ent
&& (!next
|| ts
< next_ts
)) {
1318 *ent_cpu
= next_cpu
;
1326 /* Find the next real entry, without updating the iterator itself */
1327 struct trace_entry
*trace_find_next_entry(struct trace_iterator
*iter
,
1328 int *ent_cpu
, u64
*ent_ts
)
1330 return __find_next_entry(iter
, ent_cpu
, ent_ts
);
1333 /* Find the next real entry, and increment the iterator to the next entry */
1334 static void *find_next_entry_inc(struct trace_iterator
*iter
)
1336 iter
->ent
= __find_next_entry(iter
, &iter
->cpu
, &iter
->ts
);
1339 trace_iterator_increment(iter
);
1341 return iter
->ent
? iter
: NULL
;
1344 static void trace_consume(struct trace_iterator
*iter
)
1346 /* Don't allow ftrace to trace into the ring buffers */
1347 ftrace_disable_cpu();
1348 ring_buffer_consume(iter
->tr
->buffer
, iter
->cpu
, &iter
->ts
);
1349 ftrace_enable_cpu();
1352 static void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1354 struct trace_iterator
*iter
= m
->private;
1360 /* can't go backwards */
1365 ent
= find_next_entry_inc(iter
);
1369 while (ent
&& iter
->idx
< i
)
1370 ent
= find_next_entry_inc(iter
);
1378 * No necessary locking here. The worst thing which can
1379 * happen is loosing events consumed at the same time
1380 * by a trace_pipe reader.
1381 * Other than that, we don't risk to crash the ring buffer
1382 * because it serializes the readers.
1384 * The current tracer is copied to avoid a global locking
1387 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
1389 struct trace_iterator
*iter
= m
->private;
1390 static struct tracer
*old_tracer
;
1391 int cpu_file
= iter
->cpu_file
;
1396 /* copy the tracer to avoid using a global lock all around */
1397 mutex_lock(&trace_types_lock
);
1398 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
1399 old_tracer
= current_trace
;
1400 *iter
->trace
= *current_trace
;
1402 mutex_unlock(&trace_types_lock
);
1404 atomic_inc(&trace_record_cmdline_disabled
);
1406 if (*pos
!= iter
->pos
) {
1411 ftrace_disable_cpu();
1413 if (cpu_file
== TRACE_PIPE_ALL_CPU
) {
1414 for_each_tracing_cpu(cpu
)
1415 ring_buffer_iter_reset(iter
->buffer_iter
[cpu
]);
1417 ring_buffer_iter_reset(iter
->buffer_iter
[cpu_file
]);
1420 ftrace_enable_cpu();
1422 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
1427 p
= s_next(m
, p
, &l
);
1430 trace_event_read_lock();
1434 static void s_stop(struct seq_file
*m
, void *p
)
1436 atomic_dec(&trace_record_cmdline_disabled
);
1437 trace_event_read_unlock();
1440 static void print_lat_help_header(struct seq_file
*m
)
1442 seq_puts(m
, "# _------=> CPU# \n");
1443 seq_puts(m
, "# / _-----=> irqs-off \n");
1444 seq_puts(m
, "# | / _----=> need-resched \n");
1445 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
1446 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
1447 seq_puts(m
, "# |||| / \n");
1448 seq_puts(m
, "# ||||| delay \n");
1449 seq_puts(m
, "# cmd pid ||||| time | caller \n");
1450 seq_puts(m
, "# \\ / ||||| \\ | / \n");
1453 static void print_func_help_header(struct seq_file
*m
)
1455 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1456 seq_puts(m
, "# | | | | |\n");
1461 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
1463 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1464 struct trace_array
*tr
= iter
->tr
;
1465 struct trace_array_cpu
*data
= tr
->data
[tr
->cpu
];
1466 struct tracer
*type
= current_trace
;
1467 unsigned long total
;
1468 unsigned long entries
;
1469 const char *name
= "preemption";
1474 entries
= ring_buffer_entries(iter
->tr
->buffer
);
1476 ring_buffer_overruns(iter
->tr
->buffer
);
1478 seq_printf(m
, "# %s latency trace v1.1.5 on %s\n",
1480 seq_puts(m
, "# -----------------------------------"
1481 "---------------------------------\n");
1482 seq_printf(m
, "# latency: %lu us, #%lu/%lu, CPU#%d |"
1483 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1484 nsecs_to_usecs(data
->saved_latency
),
1488 #if defined(CONFIG_PREEMPT_NONE)
1490 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1492 #elif defined(CONFIG_PREEMPT)
1497 /* These are reserved for later use */
1500 seq_printf(m
, " #P:%d)\n", num_online_cpus());
1504 seq_puts(m
, "# -----------------\n");
1505 seq_printf(m
, "# | task: %.16s-%d "
1506 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1507 data
->comm
, data
->pid
, data
->uid
, data
->nice
,
1508 data
->policy
, data
->rt_priority
);
1509 seq_puts(m
, "# -----------------\n");
1511 if (data
->critical_start
) {
1512 seq_puts(m
, "# => started at: ");
1513 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
1514 trace_print_seq(m
, &iter
->seq
);
1515 seq_puts(m
, "\n# => ended at: ");
1516 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
1517 trace_print_seq(m
, &iter
->seq
);
1518 seq_puts(m
, "\n#\n");
1524 static void test_cpu_buff_start(struct trace_iterator
*iter
)
1526 struct trace_seq
*s
= &iter
->seq
;
1528 if (!(trace_flags
& TRACE_ITER_ANNOTATE
))
1531 if (!(iter
->iter_flags
& TRACE_FILE_ANNOTATE
))
1534 if (cpumask_test_cpu(iter
->cpu
, iter
->started
))
1537 cpumask_set_cpu(iter
->cpu
, iter
->started
);
1539 /* Don't print started cpu buffer for the first entry of the trace */
1541 trace_seq_printf(s
, "##### CPU %u buffer started ####\n",
1545 static enum print_line_t
print_trace_fmt(struct trace_iterator
*iter
)
1547 struct trace_seq
*s
= &iter
->seq
;
1548 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1549 struct trace_entry
*entry
;
1550 struct trace_event
*event
;
1554 test_cpu_buff_start(iter
);
1556 event
= ftrace_find_event(entry
->type
);
1558 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1559 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
1560 if (!trace_print_lat_context(iter
))
1563 if (!trace_print_context(iter
))
1569 return event
->trace(iter
, sym_flags
);
1571 if (!trace_seq_printf(s
, "Unknown type %d\n", entry
->type
))
1574 return TRACE_TYPE_HANDLED
;
1576 return TRACE_TYPE_PARTIAL_LINE
;
1579 static enum print_line_t
print_raw_fmt(struct trace_iterator
*iter
)
1581 struct trace_seq
*s
= &iter
->seq
;
1582 struct trace_entry
*entry
;
1583 struct trace_event
*event
;
1587 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1588 if (!trace_seq_printf(s
, "%d %d %llu ",
1589 entry
->pid
, iter
->cpu
, iter
->ts
))
1593 event
= ftrace_find_event(entry
->type
);
1595 return event
->raw(iter
, 0);
1597 if (!trace_seq_printf(s
, "%d ?\n", entry
->type
))
1600 return TRACE_TYPE_HANDLED
;
1602 return TRACE_TYPE_PARTIAL_LINE
;
1605 static enum print_line_t
print_hex_fmt(struct trace_iterator
*iter
)
1607 struct trace_seq
*s
= &iter
->seq
;
1608 unsigned char newline
= '\n';
1609 struct trace_entry
*entry
;
1610 struct trace_event
*event
;
1614 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1615 SEQ_PUT_HEX_FIELD_RET(s
, entry
->pid
);
1616 SEQ_PUT_HEX_FIELD_RET(s
, iter
->cpu
);
1617 SEQ_PUT_HEX_FIELD_RET(s
, iter
->ts
);
1620 event
= ftrace_find_event(entry
->type
);
1622 enum print_line_t ret
= event
->hex(iter
, 0);
1623 if (ret
!= TRACE_TYPE_HANDLED
)
1627 SEQ_PUT_FIELD_RET(s
, newline
);
1629 return TRACE_TYPE_HANDLED
;
1632 static enum print_line_t
print_bin_fmt(struct trace_iterator
*iter
)
1634 struct trace_seq
*s
= &iter
->seq
;
1635 struct trace_entry
*entry
;
1636 struct trace_event
*event
;
1640 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1641 SEQ_PUT_FIELD_RET(s
, entry
->pid
);
1642 SEQ_PUT_FIELD_RET(s
, iter
->cpu
);
1643 SEQ_PUT_FIELD_RET(s
, iter
->ts
);
1646 event
= ftrace_find_event(entry
->type
);
1647 return event
? event
->binary(iter
, 0) : TRACE_TYPE_HANDLED
;
1650 static int trace_empty(struct trace_iterator
*iter
)
1654 /* If we are looking at one CPU buffer, only check that one */
1655 if (iter
->cpu_file
!= TRACE_PIPE_ALL_CPU
) {
1656 cpu
= iter
->cpu_file
;
1657 if (iter
->buffer_iter
[cpu
]) {
1658 if (!ring_buffer_iter_empty(iter
->buffer_iter
[cpu
]))
1661 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
1667 for_each_tracing_cpu(cpu
) {
1668 if (iter
->buffer_iter
[cpu
]) {
1669 if (!ring_buffer_iter_empty(iter
->buffer_iter
[cpu
]))
1672 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
1680 /* Called with trace_event_read_lock() held. */
1681 static enum print_line_t
print_trace_line(struct trace_iterator
*iter
)
1683 enum print_line_t ret
;
1685 if (iter
->trace
&& iter
->trace
->print_line
) {
1686 ret
= iter
->trace
->print_line(iter
);
1687 if (ret
!= TRACE_TYPE_UNHANDLED
)
1691 if (iter
->ent
->type
== TRACE_BPRINT
&&
1692 trace_flags
& TRACE_ITER_PRINTK
&&
1693 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
1694 return trace_print_bprintk_msg_only(iter
);
1696 if (iter
->ent
->type
== TRACE_PRINT
&&
1697 trace_flags
& TRACE_ITER_PRINTK
&&
1698 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
1699 return trace_print_printk_msg_only(iter
);
1701 if (trace_flags
& TRACE_ITER_BIN
)
1702 return print_bin_fmt(iter
);
1704 if (trace_flags
& TRACE_ITER_HEX
)
1705 return print_hex_fmt(iter
);
1707 if (trace_flags
& TRACE_ITER_RAW
)
1708 return print_raw_fmt(iter
);
1710 return print_trace_fmt(iter
);
1713 static int s_show(struct seq_file
*m
, void *v
)
1715 struct trace_iterator
*iter
= v
;
1717 if (iter
->ent
== NULL
) {
1719 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
1722 if (iter
->trace
&& iter
->trace
->print_header
)
1723 iter
->trace
->print_header(m
);
1724 else if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
1725 /* print nothing if the buffers are empty */
1726 if (trace_empty(iter
))
1728 print_trace_header(m
, iter
);
1729 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1730 print_lat_help_header(m
);
1732 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1733 print_func_help_header(m
);
1736 print_trace_line(iter
);
1737 trace_print_seq(m
, &iter
->seq
);
1743 static struct seq_operations tracer_seq_ops
= {
1750 static struct trace_iterator
*
1751 __tracing_open(struct inode
*inode
, struct file
*file
)
1753 long cpu_file
= (long) inode
->i_private
;
1754 void *fail_ret
= ERR_PTR(-ENOMEM
);
1755 struct trace_iterator
*iter
;
1759 if (tracing_disabled
)
1760 return ERR_PTR(-ENODEV
);
1762 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
1764 return ERR_PTR(-ENOMEM
);
1767 * We make a copy of the current tracer to avoid concurrent
1768 * changes on it while we are reading.
1770 mutex_lock(&trace_types_lock
);
1771 iter
->trace
= kzalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
1776 *iter
->trace
= *current_trace
;
1778 if (!alloc_cpumask_var(&iter
->started
, GFP_KERNEL
))
1781 cpumask_clear(iter
->started
);
1783 if (current_trace
&& current_trace
->print_max
)
1786 iter
->tr
= &global_trace
;
1788 mutex_init(&iter
->mutex
);
1789 iter
->cpu_file
= cpu_file
;
1791 /* Notify the tracer early; before we stop tracing. */
1792 if (iter
->trace
&& iter
->trace
->open
)
1793 iter
->trace
->open(iter
);
1795 /* Annotate start of buffers if we had overruns */
1796 if (ring_buffer_overruns(iter
->tr
->buffer
))
1797 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
1799 if (iter
->cpu_file
== TRACE_PIPE_ALL_CPU
) {
1800 for_each_tracing_cpu(cpu
) {
1802 iter
->buffer_iter
[cpu
] =
1803 ring_buffer_read_start(iter
->tr
->buffer
, cpu
);
1806 cpu
= iter
->cpu_file
;
1807 iter
->buffer_iter
[cpu
] =
1808 ring_buffer_read_start(iter
->tr
->buffer
, cpu
);
1811 /* TODO stop tracer */
1812 ret
= seq_open(file
, &tracer_seq_ops
);
1814 fail_ret
= ERR_PTR(ret
);
1818 m
= file
->private_data
;
1821 /* stop the trace while dumping */
1824 mutex_unlock(&trace_types_lock
);
1829 for_each_tracing_cpu(cpu
) {
1830 if (iter
->buffer_iter
[cpu
])
1831 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
1833 free_cpumask_var(iter
->started
);
1835 mutex_unlock(&trace_types_lock
);
1842 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
1844 if (tracing_disabled
)
1847 filp
->private_data
= inode
->i_private
;
1851 static int tracing_release(struct inode
*inode
, struct file
*file
)
1853 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
1854 struct trace_iterator
*iter
;
1857 if (!(file
->f_mode
& FMODE_READ
))
1862 mutex_lock(&trace_types_lock
);
1863 for_each_tracing_cpu(cpu
) {
1864 if (iter
->buffer_iter
[cpu
])
1865 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
1868 if (iter
->trace
&& iter
->trace
->close
)
1869 iter
->trace
->close(iter
);
1871 /* reenable tracing if it was previously enabled */
1873 mutex_unlock(&trace_types_lock
);
1875 seq_release(inode
, file
);
1876 mutex_destroy(&iter
->mutex
);
1877 free_cpumask_var(iter
->started
);
1883 static int tracing_open(struct inode
*inode
, struct file
*file
)
1885 struct trace_iterator
*iter
;
1888 /* If this file was open for write, then erase contents */
1889 if ((file
->f_mode
& FMODE_WRITE
) &&
1890 (file
->f_flags
& O_TRUNC
)) {
1891 long cpu
= (long) inode
->i_private
;
1893 if (cpu
== TRACE_PIPE_ALL_CPU
)
1894 tracing_reset_online_cpus(&global_trace
);
1896 tracing_reset(&global_trace
, cpu
);
1899 if (file
->f_mode
& FMODE_READ
) {
1900 iter
= __tracing_open(inode
, file
);
1902 ret
= PTR_ERR(iter
);
1903 else if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
1904 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
1910 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1912 struct tracer
*t
= v
;
1922 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
1927 mutex_lock(&trace_types_lock
);
1928 for (t
= trace_types
; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
1934 static void t_stop(struct seq_file
*m
, void *p
)
1936 mutex_unlock(&trace_types_lock
);
1939 static int t_show(struct seq_file
*m
, void *v
)
1941 struct tracer
*t
= v
;
1946 seq_printf(m
, "%s", t
->name
);
1955 static struct seq_operations show_traces_seq_ops
= {
1962 static int show_traces_open(struct inode
*inode
, struct file
*file
)
1964 if (tracing_disabled
)
1967 return seq_open(file
, &show_traces_seq_ops
);
1971 tracing_write_stub(struct file
*filp
, const char __user
*ubuf
,
1972 size_t count
, loff_t
*ppos
)
1977 static const struct file_operations tracing_fops
= {
1978 .open
= tracing_open
,
1980 .write
= tracing_write_stub
,
1981 .llseek
= seq_lseek
,
1982 .release
= tracing_release
,
1985 static const struct file_operations show_traces_fops
= {
1986 .open
= show_traces_open
,
1988 .release
= seq_release
,
1992 * Only trace on a CPU if the bitmask is set:
1994 static cpumask_var_t tracing_cpumask
;
1997 * The tracer itself will not take this lock, but still we want
1998 * to provide a consistent cpumask to user-space:
2000 static DEFINE_MUTEX(tracing_cpumask_update_lock
);
2003 * Temporary storage for the character representation of the
2004 * CPU bitmask (and one more byte for the newline):
2006 static char mask_str
[NR_CPUS
+ 1];
2009 tracing_cpumask_read(struct file
*filp
, char __user
*ubuf
,
2010 size_t count
, loff_t
*ppos
)
2014 mutex_lock(&tracing_cpumask_update_lock
);
2016 len
= cpumask_scnprintf(mask_str
, count
, tracing_cpumask
);
2017 if (count
- len
< 2) {
2021 len
+= sprintf(mask_str
+ len
, "\n");
2022 count
= simple_read_from_buffer(ubuf
, count
, ppos
, mask_str
, NR_CPUS
+1);
2025 mutex_unlock(&tracing_cpumask_update_lock
);
2031 tracing_cpumask_write(struct file
*filp
, const char __user
*ubuf
,
2032 size_t count
, loff_t
*ppos
)
2035 cpumask_var_t tracing_cpumask_new
;
2037 if (!alloc_cpumask_var(&tracing_cpumask_new
, GFP_KERNEL
))
2040 err
= cpumask_parse_user(ubuf
, count
, tracing_cpumask_new
);
2044 mutex_lock(&tracing_cpumask_update_lock
);
2046 local_irq_disable();
2047 __raw_spin_lock(&ftrace_max_lock
);
2048 for_each_tracing_cpu(cpu
) {
2050 * Increase/decrease the disabled counter if we are
2051 * about to flip a bit in the cpumask:
2053 if (cpumask_test_cpu(cpu
, tracing_cpumask
) &&
2054 !cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
2055 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
2057 if (!cpumask_test_cpu(cpu
, tracing_cpumask
) &&
2058 cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
2059 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
2062 __raw_spin_unlock(&ftrace_max_lock
);
2065 cpumask_copy(tracing_cpumask
, tracing_cpumask_new
);
2067 mutex_unlock(&tracing_cpumask_update_lock
);
2068 free_cpumask_var(tracing_cpumask_new
);
2073 free_cpumask_var(tracing_cpumask_new
);
2078 static const struct file_operations tracing_cpumask_fops
= {
2079 .open
= tracing_open_generic
,
2080 .read
= tracing_cpumask_read
,
2081 .write
= tracing_cpumask_write
,
2085 tracing_trace_options_read(struct file
*filp
, char __user
*ubuf
,
2086 size_t cnt
, loff_t
*ppos
)
2088 struct tracer_opt
*trace_opts
;
2096 /* calculate max size */
2097 for (i
= 0; trace_options
[i
]; i
++) {
2098 len
+= strlen(trace_options
[i
]);
2099 len
+= 3; /* "no" and newline */
2102 mutex_lock(&trace_types_lock
);
2103 tracer_flags
= current_trace
->flags
->val
;
2104 trace_opts
= current_trace
->flags
->opts
;
2107 * Increase the size with names of options specific
2108 * of the current tracer.
2110 for (i
= 0; trace_opts
[i
].name
; i
++) {
2111 len
+= strlen(trace_opts
[i
].name
);
2112 len
+= 3; /* "no" and newline */
2116 buf
= kmalloc(len
+ 1, GFP_KERNEL
);
2118 mutex_unlock(&trace_types_lock
);
2122 for (i
= 0; trace_options
[i
]; i
++) {
2123 if (trace_flags
& (1 << i
))
2124 r
+= sprintf(buf
+ r
, "%s\n", trace_options
[i
]);
2126 r
+= sprintf(buf
+ r
, "no%s\n", trace_options
[i
]);
2129 for (i
= 0; trace_opts
[i
].name
; i
++) {
2130 if (tracer_flags
& trace_opts
[i
].bit
)
2131 r
+= sprintf(buf
+ r
, "%s\n",
2132 trace_opts
[i
].name
);
2134 r
+= sprintf(buf
+ r
, "no%s\n",
2135 trace_opts
[i
].name
);
2137 mutex_unlock(&trace_types_lock
);
2139 WARN_ON(r
>= len
+ 1);
2141 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2147 /* Try to assign a tracer specific option */
2148 static int set_tracer_option(struct tracer
*trace
, char *cmp
, int neg
)
2150 struct tracer_flags
*tracer_flags
= trace
->flags
;
2151 struct tracer_opt
*opts
= NULL
;
2155 for (i
= 0; tracer_flags
->opts
[i
].name
; i
++) {
2156 opts
= &tracer_flags
->opts
[i
];
2157 len
= strlen(opts
->name
);
2159 if (strncmp(cmp
, opts
->name
, len
) == 0) {
2160 ret
= trace
->set_flag(tracer_flags
->val
,
2166 if (!tracer_flags
->opts
[i
].name
)
2169 /* Refused to handle */
2174 tracer_flags
->val
&= ~opts
->bit
;
2176 tracer_flags
->val
|= opts
->bit
;
2181 static void set_tracer_flags(unsigned int mask
, int enabled
)
2183 /* do nothing if flag is already set */
2184 if (!!(trace_flags
& mask
) == !!enabled
)
2188 trace_flags
|= mask
;
2190 trace_flags
&= ~mask
;
2194 tracing_trace_options_write(struct file
*filp
, const char __user
*ubuf
,
2195 size_t cnt
, loff_t
*ppos
)
2203 if (cnt
>= sizeof(buf
))
2206 if (copy_from_user(&buf
, ubuf
, cnt
))
2211 if (strncmp(buf
, "no", 2) == 0) {
2216 for (i
= 0; trace_options
[i
]; i
++) {
2217 int len
= strlen(trace_options
[i
]);
2219 if (strncmp(cmp
, trace_options
[i
], len
) == 0) {
2220 set_tracer_flags(1 << i
, !neg
);
2225 /* If no option could be set, test the specific tracer options */
2226 if (!trace_options
[i
]) {
2227 mutex_lock(&trace_types_lock
);
2228 ret
= set_tracer_option(current_trace
, cmp
, neg
);
2229 mutex_unlock(&trace_types_lock
);
2239 static const struct file_operations tracing_iter_fops
= {
2240 .open
= tracing_open_generic
,
2241 .read
= tracing_trace_options_read
,
2242 .write
= tracing_trace_options_write
,
2245 static const char readme_msg
[] =
2246 "tracing mini-HOWTO:\n\n"
2247 "# mount -t debugfs nodev /sys/kernel/debug\n\n"
2248 "# cat /sys/kernel/debug/tracing/available_tracers\n"
2249 "wakeup preemptirqsoff preemptoff irqsoff function sched_switch nop\n\n"
2250 "# cat /sys/kernel/debug/tracing/current_tracer\n"
2252 "# echo sched_switch > /sys/kernel/debug/tracing/current_tracer\n"
2253 "# cat /sys/kernel/debug/tracing/current_tracer\n"
2255 "# cat /sys/kernel/debug/tracing/trace_options\n"
2256 "noprint-parent nosym-offset nosym-addr noverbose\n"
2257 "# echo print-parent > /sys/kernel/debug/tracing/trace_options\n"
2258 "# echo 1 > /sys/kernel/debug/tracing/tracing_enabled\n"
2259 "# cat /sys/kernel/debug/tracing/trace > /tmp/trace.txt\n"
2260 "# echo 0 > /sys/kernel/debug/tracing/tracing_enabled\n"
2264 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
2265 size_t cnt
, loff_t
*ppos
)
2267 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
2268 readme_msg
, strlen(readme_msg
));
2271 static const struct file_operations tracing_readme_fops
= {
2272 .open
= tracing_open_generic
,
2273 .read
= tracing_readme_read
,
2277 tracing_saved_cmdlines_read(struct file
*file
, char __user
*ubuf
,
2278 size_t cnt
, loff_t
*ppos
)
2287 file_buf
= kmalloc(SAVED_CMDLINES
*(16+TASK_COMM_LEN
), GFP_KERNEL
);
2291 buf_comm
= kmalloc(TASK_COMM_LEN
, GFP_KERNEL
);
2299 for (i
= 0; i
< SAVED_CMDLINES
; i
++) {
2302 pid
= map_cmdline_to_pid
[i
];
2303 if (pid
== -1 || pid
== NO_CMDLINE_MAP
)
2306 trace_find_cmdline(pid
, buf_comm
);
2307 r
= sprintf(buf
, "%d %s\n", pid
, buf_comm
);
2312 len
= simple_read_from_buffer(ubuf
, cnt
, ppos
,
2321 static const struct file_operations tracing_saved_cmdlines_fops
= {
2322 .open
= tracing_open_generic
,
2323 .read
= tracing_saved_cmdlines_read
,
2327 tracing_ctrl_read(struct file
*filp
, char __user
*ubuf
,
2328 size_t cnt
, loff_t
*ppos
)
2333 r
= sprintf(buf
, "%u\n", tracer_enabled
);
2334 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2338 tracing_ctrl_write(struct file
*filp
, const char __user
*ubuf
,
2339 size_t cnt
, loff_t
*ppos
)
2341 struct trace_array
*tr
= filp
->private_data
;
2346 if (cnt
>= sizeof(buf
))
2349 if (copy_from_user(&buf
, ubuf
, cnt
))
2354 ret
= strict_strtoul(buf
, 10, &val
);
2360 mutex_lock(&trace_types_lock
);
2361 if (tracer_enabled
^ val
) {
2364 if (current_trace
->start
)
2365 current_trace
->start(tr
);
2370 if (current_trace
->stop
)
2371 current_trace
->stop(tr
);
2374 mutex_unlock(&trace_types_lock
);
2382 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
2383 size_t cnt
, loff_t
*ppos
)
2385 char buf
[max_tracer_type_len
+2];
2388 mutex_lock(&trace_types_lock
);
2390 r
= sprintf(buf
, "%s\n", current_trace
->name
);
2392 r
= sprintf(buf
, "\n");
2393 mutex_unlock(&trace_types_lock
);
2395 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2398 int tracer_init(struct tracer
*t
, struct trace_array
*tr
)
2400 tracing_reset_online_cpus(tr
);
2404 static int tracing_resize_ring_buffer(unsigned long size
)
2409 * If kernel or user changes the size of the ring buffer
2410 * we use the size that was given, and we can forget about
2411 * expanding it later.
2413 ring_buffer_expanded
= 1;
2415 ret
= ring_buffer_resize(global_trace
.buffer
, size
);
2419 ret
= ring_buffer_resize(max_tr
.buffer
, size
);
2423 r
= ring_buffer_resize(global_trace
.buffer
,
2424 global_trace
.entries
);
2427 * AARGH! We are left with different
2428 * size max buffer!!!!
2429 * The max buffer is our "snapshot" buffer.
2430 * When a tracer needs a snapshot (one of the
2431 * latency tracers), it swaps the max buffer
2432 * with the saved snap shot. We succeeded to
2433 * update the size of the main buffer, but failed to
2434 * update the size of the max buffer. But when we tried
2435 * to reset the main buffer to the original size, we
2436 * failed there too. This is very unlikely to
2437 * happen, but if it does, warn and kill all
2441 tracing_disabled
= 1;
2446 global_trace
.entries
= size
;
2452 * tracing_update_buffers - used by tracing facility to expand ring buffers
2454 * To save on memory when the tracing is never used on a system with it
2455 * configured in. The ring buffers are set to a minimum size. But once
2456 * a user starts to use the tracing facility, then they need to grow
2457 * to their default size.
2459 * This function is to be called when a tracer is about to be used.
2461 int tracing_update_buffers(void)
2465 mutex_lock(&trace_types_lock
);
2466 if (!ring_buffer_expanded
)
2467 ret
= tracing_resize_ring_buffer(trace_buf_size
);
2468 mutex_unlock(&trace_types_lock
);
2473 struct trace_option_dentry
;
2475 static struct trace_option_dentry
*
2476 create_trace_option_files(struct tracer
*tracer
);
2479 destroy_trace_option_files(struct trace_option_dentry
*topts
);
2481 static int tracing_set_tracer(const char *buf
)
2483 static struct trace_option_dentry
*topts
;
2484 struct trace_array
*tr
= &global_trace
;
2488 mutex_lock(&trace_types_lock
);
2490 if (!ring_buffer_expanded
) {
2491 ret
= tracing_resize_ring_buffer(trace_buf_size
);
2497 for (t
= trace_types
; t
; t
= t
->next
) {
2498 if (strcmp(t
->name
, buf
) == 0)
2505 if (t
== current_trace
)
2508 trace_branch_disable();
2509 if (current_trace
&& current_trace
->reset
)
2510 current_trace
->reset(tr
);
2512 destroy_trace_option_files(topts
);
2516 topts
= create_trace_option_files(current_trace
);
2519 ret
= tracer_init(t
, tr
);
2524 trace_branch_enable(tr
);
2526 mutex_unlock(&trace_types_lock
);
2532 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
2533 size_t cnt
, loff_t
*ppos
)
2535 char buf
[max_tracer_type_len
+1];
2542 if (cnt
> max_tracer_type_len
)
2543 cnt
= max_tracer_type_len
;
2545 if (copy_from_user(&buf
, ubuf
, cnt
))
2550 /* strip ending whitespace. */
2551 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
2554 err
= tracing_set_tracer(buf
);
2564 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
2565 size_t cnt
, loff_t
*ppos
)
2567 unsigned long *ptr
= filp
->private_data
;
2571 r
= snprintf(buf
, sizeof(buf
), "%ld\n",
2572 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
2573 if (r
> sizeof(buf
))
2575 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2579 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
2580 size_t cnt
, loff_t
*ppos
)
2582 unsigned long *ptr
= filp
->private_data
;
2587 if (cnt
>= sizeof(buf
))
2590 if (copy_from_user(&buf
, ubuf
, cnt
))
2595 ret
= strict_strtoul(buf
, 10, &val
);
2604 static int tracing_open_pipe(struct inode
*inode
, struct file
*filp
)
2606 long cpu_file
= (long) inode
->i_private
;
2607 struct trace_iterator
*iter
;
2610 if (tracing_disabled
)
2613 mutex_lock(&trace_types_lock
);
2615 /* We only allow one reader per cpu */
2616 if (cpu_file
== TRACE_PIPE_ALL_CPU
) {
2617 if (!cpumask_empty(tracing_reader_cpumask
)) {
2621 cpumask_setall(tracing_reader_cpumask
);
2623 if (!cpumask_test_cpu(cpu_file
, tracing_reader_cpumask
))
2624 cpumask_set_cpu(cpu_file
, tracing_reader_cpumask
);
2631 /* create a buffer to store the information to pass to userspace */
2632 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2639 * We make a copy of the current tracer to avoid concurrent
2640 * changes on it while we are reading.
2642 iter
->trace
= kmalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
2648 *iter
->trace
= *current_trace
;
2650 if (!alloc_cpumask_var(&iter
->started
, GFP_KERNEL
)) {
2655 /* trace pipe does not show start of buffer */
2656 cpumask_setall(iter
->started
);
2658 if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
2659 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
2661 iter
->cpu_file
= cpu_file
;
2662 iter
->tr
= &global_trace
;
2663 mutex_init(&iter
->mutex
);
2664 filp
->private_data
= iter
;
2666 if (iter
->trace
->pipe_open
)
2667 iter
->trace
->pipe_open(iter
);
2670 mutex_unlock(&trace_types_lock
);
2676 mutex_unlock(&trace_types_lock
);
2680 static int tracing_release_pipe(struct inode
*inode
, struct file
*file
)
2682 struct trace_iterator
*iter
= file
->private_data
;
2684 mutex_lock(&trace_types_lock
);
2686 if (iter
->cpu_file
== TRACE_PIPE_ALL_CPU
)
2687 cpumask_clear(tracing_reader_cpumask
);
2689 cpumask_clear_cpu(iter
->cpu_file
, tracing_reader_cpumask
);
2691 mutex_unlock(&trace_types_lock
);
2693 free_cpumask_var(iter
->started
);
2694 mutex_destroy(&iter
->mutex
);
2702 tracing_poll_pipe(struct file
*filp
, poll_table
*poll_table
)
2704 struct trace_iterator
*iter
= filp
->private_data
;
2706 if (trace_flags
& TRACE_ITER_BLOCK
) {
2708 * Always select as readable when in blocking mode
2710 return POLLIN
| POLLRDNORM
;
2712 if (!trace_empty(iter
))
2713 return POLLIN
| POLLRDNORM
;
2714 poll_wait(filp
, &trace_wait
, poll_table
);
2715 if (!trace_empty(iter
))
2716 return POLLIN
| POLLRDNORM
;
2723 void default_wait_pipe(struct trace_iterator
*iter
)
2727 prepare_to_wait(&trace_wait
, &wait
, TASK_INTERRUPTIBLE
);
2729 if (trace_empty(iter
))
2732 finish_wait(&trace_wait
, &wait
);
2736 * This is a make-shift waitqueue.
2737 * A tracer might use this callback on some rare cases:
2739 * 1) the current tracer might hold the runqueue lock when it wakes up
2740 * a reader, hence a deadlock (sched, function, and function graph tracers)
2741 * 2) the function tracers, trace all functions, we don't want
2742 * the overhead of calling wake_up and friends
2743 * (and tracing them too)
2745 * Anyway, this is really very primitive wakeup.
2747 void poll_wait_pipe(struct trace_iterator
*iter
)
2749 set_current_state(TASK_INTERRUPTIBLE
);
2750 /* sleep for 100 msecs, and try again. */
2751 schedule_timeout(HZ
/ 10);
2754 /* Must be called with trace_types_lock mutex held. */
2755 static int tracing_wait_pipe(struct file
*filp
)
2757 struct trace_iterator
*iter
= filp
->private_data
;
2759 while (trace_empty(iter
)) {
2761 if ((filp
->f_flags
& O_NONBLOCK
)) {
2765 mutex_unlock(&iter
->mutex
);
2767 iter
->trace
->wait_pipe(iter
);
2769 mutex_lock(&iter
->mutex
);
2771 if (signal_pending(current
))
2775 * We block until we read something and tracing is disabled.
2776 * We still block if tracing is disabled, but we have never
2777 * read anything. This allows a user to cat this file, and
2778 * then enable tracing. But after we have read something,
2779 * we give an EOF when tracing is again disabled.
2781 * iter->pos will be 0 if we haven't read anything.
2783 if (!tracer_enabled
&& iter
->pos
)
2794 tracing_read_pipe(struct file
*filp
, char __user
*ubuf
,
2795 size_t cnt
, loff_t
*ppos
)
2797 struct trace_iterator
*iter
= filp
->private_data
;
2798 static struct tracer
*old_tracer
;
2801 /* return any leftover data */
2802 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
2806 trace_seq_init(&iter
->seq
);
2808 /* copy the tracer to avoid using a global lock all around */
2809 mutex_lock(&trace_types_lock
);
2810 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
2811 old_tracer
= current_trace
;
2812 *iter
->trace
= *current_trace
;
2814 mutex_unlock(&trace_types_lock
);
2817 * Avoid more than one consumer on a single file descriptor
2818 * This is just a matter of traces coherency, the ring buffer itself
2821 mutex_lock(&iter
->mutex
);
2822 if (iter
->trace
->read
) {
2823 sret
= iter
->trace
->read(iter
, filp
, ubuf
, cnt
, ppos
);
2829 sret
= tracing_wait_pipe(filp
);
2833 /* stop when tracing is finished */
2834 if (trace_empty(iter
)) {
2839 if (cnt
>= PAGE_SIZE
)
2840 cnt
= PAGE_SIZE
- 1;
2842 /* reset all but tr, trace, and overruns */
2843 memset(&iter
->seq
, 0,
2844 sizeof(struct trace_iterator
) -
2845 offsetof(struct trace_iterator
, seq
));
2848 trace_event_read_lock();
2849 while (find_next_entry_inc(iter
) != NULL
) {
2850 enum print_line_t ret
;
2851 int len
= iter
->seq
.len
;
2853 ret
= print_trace_line(iter
);
2854 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
2855 /* don't print partial lines */
2856 iter
->seq
.len
= len
;
2859 if (ret
!= TRACE_TYPE_NO_CONSUME
)
2860 trace_consume(iter
);
2862 if (iter
->seq
.len
>= cnt
)
2865 trace_event_read_unlock();
2867 /* Now copy what we have to the user */
2868 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
2869 if (iter
->seq
.readpos
>= iter
->seq
.len
)
2870 trace_seq_init(&iter
->seq
);
2873 * If there was nothing to send to user, inspite of consuming trace
2874 * entries, go back to wait for more entries.
2880 mutex_unlock(&iter
->mutex
);
2885 static void tracing_pipe_buf_release(struct pipe_inode_info
*pipe
,
2886 struct pipe_buffer
*buf
)
2888 __free_page(buf
->page
);
2891 static void tracing_spd_release_pipe(struct splice_pipe_desc
*spd
,
2894 __free_page(spd
->pages
[idx
]);
2897 static struct pipe_buf_operations tracing_pipe_buf_ops
= {
2899 .map
= generic_pipe_buf_map
,
2900 .unmap
= generic_pipe_buf_unmap
,
2901 .confirm
= generic_pipe_buf_confirm
,
2902 .release
= tracing_pipe_buf_release
,
2903 .steal
= generic_pipe_buf_steal
,
2904 .get
= generic_pipe_buf_get
,
2908 tracing_fill_pipe_page(size_t rem
, struct trace_iterator
*iter
)
2913 /* Seq buffer is page-sized, exactly what we need. */
2915 count
= iter
->seq
.len
;
2916 ret
= print_trace_line(iter
);
2917 count
= iter
->seq
.len
- count
;
2920 iter
->seq
.len
-= count
;
2923 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
2924 iter
->seq
.len
-= count
;
2928 if (ret
!= TRACE_TYPE_NO_CONSUME
)
2929 trace_consume(iter
);
2931 if (!find_next_entry_inc(iter
)) {
2941 static ssize_t
tracing_splice_read_pipe(struct file
*filp
,
2943 struct pipe_inode_info
*pipe
,
2947 struct page
*pages
[PIPE_BUFFERS
];
2948 struct partial_page partial
[PIPE_BUFFERS
];
2949 struct trace_iterator
*iter
= filp
->private_data
;
2950 struct splice_pipe_desc spd
= {
2953 .nr_pages
= 0, /* This gets updated below. */
2955 .ops
= &tracing_pipe_buf_ops
,
2956 .spd_release
= tracing_spd_release_pipe
,
2958 static struct tracer
*old_tracer
;
2963 /* copy the tracer to avoid using a global lock all around */
2964 mutex_lock(&trace_types_lock
);
2965 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
2966 old_tracer
= current_trace
;
2967 *iter
->trace
= *current_trace
;
2969 mutex_unlock(&trace_types_lock
);
2971 mutex_lock(&iter
->mutex
);
2973 if (iter
->trace
->splice_read
) {
2974 ret
= iter
->trace
->splice_read(iter
, filp
,
2975 ppos
, pipe
, len
, flags
);
2980 ret
= tracing_wait_pipe(filp
);
2984 if (!iter
->ent
&& !find_next_entry_inc(iter
)) {
2989 trace_event_read_lock();
2991 /* Fill as many pages as possible. */
2992 for (i
= 0, rem
= len
; i
< PIPE_BUFFERS
&& rem
; i
++) {
2993 pages
[i
] = alloc_page(GFP_KERNEL
);
2997 rem
= tracing_fill_pipe_page(rem
, iter
);
2999 /* Copy the data into the page, so we can start over. */
3000 ret
= trace_seq_to_buffer(&iter
->seq
,
3001 page_address(pages
[i
]),
3004 __free_page(pages
[i
]);
3007 partial
[i
].offset
= 0;
3008 partial
[i
].len
= iter
->seq
.len
;
3010 trace_seq_init(&iter
->seq
);
3013 trace_event_read_unlock();
3014 mutex_unlock(&iter
->mutex
);
3018 return splice_to_pipe(pipe
, &spd
);
3021 mutex_unlock(&iter
->mutex
);
3027 tracing_entries_read(struct file
*filp
, char __user
*ubuf
,
3028 size_t cnt
, loff_t
*ppos
)
3030 struct trace_array
*tr
= filp
->private_data
;
3034 mutex_lock(&trace_types_lock
);
3035 if (!ring_buffer_expanded
)
3036 r
= sprintf(buf
, "%lu (expanded: %lu)\n",
3038 trace_buf_size
>> 10);
3040 r
= sprintf(buf
, "%lu\n", tr
->entries
>> 10);
3041 mutex_unlock(&trace_types_lock
);
3043 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3047 tracing_entries_write(struct file
*filp
, const char __user
*ubuf
,
3048 size_t cnt
, loff_t
*ppos
)
3054 if (cnt
>= sizeof(buf
))
3057 if (copy_from_user(&buf
, ubuf
, cnt
))
3062 ret
= strict_strtoul(buf
, 10, &val
);
3066 /* must have at least 1 entry */
3070 mutex_lock(&trace_types_lock
);
3074 /* disable all cpu buffers */
3075 for_each_tracing_cpu(cpu
) {
3076 if (global_trace
.data
[cpu
])
3077 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
3078 if (max_tr
.data
[cpu
])
3079 atomic_inc(&max_tr
.data
[cpu
]->disabled
);
3082 /* value is in KB */
3085 if (val
!= global_trace
.entries
) {
3086 ret
= tracing_resize_ring_buffer(val
);
3095 /* If check pages failed, return ENOMEM */
3096 if (tracing_disabled
)
3099 for_each_tracing_cpu(cpu
) {
3100 if (global_trace
.data
[cpu
])
3101 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
3102 if (max_tr
.data
[cpu
])
3103 atomic_dec(&max_tr
.data
[cpu
]->disabled
);
3107 max_tr
.entries
= global_trace
.entries
;
3108 mutex_unlock(&trace_types_lock
);
3113 static int mark_printk(const char *fmt
, ...)
3117 va_start(args
, fmt
);
3118 ret
= trace_vprintk(0, fmt
, args
);
3124 tracing_mark_write(struct file
*filp
, const char __user
*ubuf
,
3125 size_t cnt
, loff_t
*fpos
)
3130 if (tracing_disabled
)
3133 if (cnt
> TRACE_BUF_SIZE
)
3134 cnt
= TRACE_BUF_SIZE
;
3136 buf
= kmalloc(cnt
+ 1, GFP_KERNEL
);
3140 if (copy_from_user(buf
, ubuf
, cnt
)) {
3145 /* Cut from the first nil or newline. */
3147 end
= strchr(buf
, '\n');
3151 cnt
= mark_printk("%s\n", buf
);
3158 static ssize_t
tracing_clock_read(struct file
*filp
, char __user
*ubuf
,
3159 size_t cnt
, loff_t
*ppos
)
3165 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++)
3166 bufiter
+= snprintf(buf
+ bufiter
, sizeof(buf
) - bufiter
,
3167 "%s%s%s%s", i
? " " : "",
3168 i
== trace_clock_id
? "[" : "", trace_clocks
[i
].name
,
3169 i
== trace_clock_id
? "]" : "");
3170 bufiter
+= snprintf(buf
+ bufiter
, sizeof(buf
) - bufiter
, "\n");
3172 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, bufiter
);
3175 static ssize_t
tracing_clock_write(struct file
*filp
, const char __user
*ubuf
,
3176 size_t cnt
, loff_t
*fpos
)
3179 const char *clockstr
;
3182 if (cnt
>= sizeof(buf
))
3185 if (copy_from_user(&buf
, ubuf
, cnt
))
3190 clockstr
= strstrip(buf
);
3192 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++) {
3193 if (strcmp(trace_clocks
[i
].name
, clockstr
) == 0)
3196 if (i
== ARRAY_SIZE(trace_clocks
))
3201 mutex_lock(&trace_types_lock
);
3203 ring_buffer_set_clock(global_trace
.buffer
, trace_clocks
[i
].func
);
3205 ring_buffer_set_clock(max_tr
.buffer
, trace_clocks
[i
].func
);
3207 mutex_unlock(&trace_types_lock
);
3214 static const struct file_operations tracing_max_lat_fops
= {
3215 .open
= tracing_open_generic
,
3216 .read
= tracing_max_lat_read
,
3217 .write
= tracing_max_lat_write
,
3220 static const struct file_operations tracing_ctrl_fops
= {
3221 .open
= tracing_open_generic
,
3222 .read
= tracing_ctrl_read
,
3223 .write
= tracing_ctrl_write
,
3226 static const struct file_operations set_tracer_fops
= {
3227 .open
= tracing_open_generic
,
3228 .read
= tracing_set_trace_read
,
3229 .write
= tracing_set_trace_write
,
3232 static const struct file_operations tracing_pipe_fops
= {
3233 .open
= tracing_open_pipe
,
3234 .poll
= tracing_poll_pipe
,
3235 .read
= tracing_read_pipe
,
3236 .splice_read
= tracing_splice_read_pipe
,
3237 .release
= tracing_release_pipe
,
3240 static const struct file_operations tracing_entries_fops
= {
3241 .open
= tracing_open_generic
,
3242 .read
= tracing_entries_read
,
3243 .write
= tracing_entries_write
,
3246 static const struct file_operations tracing_mark_fops
= {
3247 .open
= tracing_open_generic
,
3248 .write
= tracing_mark_write
,
3251 static const struct file_operations trace_clock_fops
= {
3252 .open
= tracing_open_generic
,
3253 .read
= tracing_clock_read
,
3254 .write
= tracing_clock_write
,
3257 struct ftrace_buffer_info
{
3258 struct trace_array
*tr
;
3264 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
)
3266 int cpu
= (int)(long)inode
->i_private
;
3267 struct ftrace_buffer_info
*info
;
3269 if (tracing_disabled
)
3272 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
3276 info
->tr
= &global_trace
;
3279 /* Force reading ring buffer for first read */
3280 info
->read
= (unsigned int)-1;
3282 filp
->private_data
= info
;
3284 return nonseekable_open(inode
, filp
);
3288 tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
3289 size_t count
, loff_t
*ppos
)
3291 struct ftrace_buffer_info
*info
= filp
->private_data
;
3300 info
->spare
= ring_buffer_alloc_read_page(info
->tr
->buffer
);
3304 /* Do we have previous read data to read? */
3305 if (info
->read
< PAGE_SIZE
)
3310 ret
= ring_buffer_read_page(info
->tr
->buffer
,
3317 pos
= ring_buffer_page_len(info
->spare
);
3319 if (pos
< PAGE_SIZE
)
3320 memset(info
->spare
+ pos
, 0, PAGE_SIZE
- pos
);
3323 size
= PAGE_SIZE
- info
->read
;
3327 ret
= copy_to_user(ubuf
, info
->spare
+ info
->read
, size
);
3338 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
)
3340 struct ftrace_buffer_info
*info
= file
->private_data
;
3343 ring_buffer_free_read_page(info
->tr
->buffer
, info
->spare
);
3350 struct ring_buffer
*buffer
;
3355 static void buffer_pipe_buf_release(struct pipe_inode_info
*pipe
,
3356 struct pipe_buffer
*buf
)
3358 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
3363 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
3368 static int buffer_pipe_buf_steal(struct pipe_inode_info
*pipe
,
3369 struct pipe_buffer
*buf
)
3374 static void buffer_pipe_buf_get(struct pipe_inode_info
*pipe
,
3375 struct pipe_buffer
*buf
)
3377 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
3382 /* Pipe buffer operations for a buffer. */
3383 static struct pipe_buf_operations buffer_pipe_buf_ops
= {
3385 .map
= generic_pipe_buf_map
,
3386 .unmap
= generic_pipe_buf_unmap
,
3387 .confirm
= generic_pipe_buf_confirm
,
3388 .release
= buffer_pipe_buf_release
,
3389 .steal
= buffer_pipe_buf_steal
,
3390 .get
= buffer_pipe_buf_get
,
3394 * Callback from splice_to_pipe(), if we need to release some pages
3395 * at the end of the spd in case we error'ed out in filling the pipe.
3397 static void buffer_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
3399 struct buffer_ref
*ref
=
3400 (struct buffer_ref
*)spd
->partial
[i
].private;
3405 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
3407 spd
->partial
[i
].private = 0;
3411 tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
3412 struct pipe_inode_info
*pipe
, size_t len
,
3415 struct ftrace_buffer_info
*info
= file
->private_data
;
3416 struct partial_page partial
[PIPE_BUFFERS
];
3417 struct page
*pages
[PIPE_BUFFERS
];
3418 struct splice_pipe_desc spd
= {
3422 .ops
= &buffer_pipe_buf_ops
,
3423 .spd_release
= buffer_spd_release
,
3425 struct buffer_ref
*ref
;
3426 int entries
, size
, i
;
3429 if (*ppos
& (PAGE_SIZE
- 1)) {
3430 WARN_ONCE(1, "Ftrace: previous read must page-align\n");
3434 if (len
& (PAGE_SIZE
- 1)) {
3435 WARN_ONCE(1, "Ftrace: splice_read should page-align\n");
3436 if (len
< PAGE_SIZE
)
3441 entries
= ring_buffer_entries_cpu(info
->tr
->buffer
, info
->cpu
);
3443 for (i
= 0; i
< PIPE_BUFFERS
&& len
&& entries
; i
++, len
-= PAGE_SIZE
) {
3447 ref
= kzalloc(sizeof(*ref
), GFP_KERNEL
);
3452 ref
->buffer
= info
->tr
->buffer
;
3453 ref
->page
= ring_buffer_alloc_read_page(ref
->buffer
);
3459 r
= ring_buffer_read_page(ref
->buffer
, &ref
->page
,
3462 ring_buffer_free_read_page(ref
->buffer
,
3469 * zero out any left over data, this is going to
3472 size
= ring_buffer_page_len(ref
->page
);
3473 if (size
< PAGE_SIZE
)
3474 memset(ref
->page
+ size
, 0, PAGE_SIZE
- size
);
3476 page
= virt_to_page(ref
->page
);
3478 spd
.pages
[i
] = page
;
3479 spd
.partial
[i
].len
= PAGE_SIZE
;
3480 spd
.partial
[i
].offset
= 0;
3481 spd
.partial
[i
].private = (unsigned long)ref
;
3485 entries
= ring_buffer_entries_cpu(info
->tr
->buffer
, info
->cpu
);
3490 /* did we read anything? */
3491 if (!spd
.nr_pages
) {
3492 if (flags
& SPLICE_F_NONBLOCK
)
3500 ret
= splice_to_pipe(pipe
, &spd
);
3505 static const struct file_operations tracing_buffers_fops
= {
3506 .open
= tracing_buffers_open
,
3507 .read
= tracing_buffers_read
,
3508 .release
= tracing_buffers_release
,
3509 .splice_read
= tracing_buffers_splice_read
,
3510 .llseek
= no_llseek
,
3514 tracing_stats_read(struct file
*filp
, char __user
*ubuf
,
3515 size_t count
, loff_t
*ppos
)
3517 unsigned long cpu
= (unsigned long)filp
->private_data
;
3518 struct trace_array
*tr
= &global_trace
;
3519 struct trace_seq
*s
;
3522 s
= kmalloc(sizeof(*s
), GFP_KERNEL
);
3528 cnt
= ring_buffer_entries_cpu(tr
->buffer
, cpu
);
3529 trace_seq_printf(s
, "entries: %ld\n", cnt
);
3531 cnt
= ring_buffer_overrun_cpu(tr
->buffer
, cpu
);
3532 trace_seq_printf(s
, "overrun: %ld\n", cnt
);
3534 cnt
= ring_buffer_commit_overrun_cpu(tr
->buffer
, cpu
);
3535 trace_seq_printf(s
, "commit overrun: %ld\n", cnt
);
3537 count
= simple_read_from_buffer(ubuf
, count
, ppos
, s
->buffer
, s
->len
);
3544 static const struct file_operations tracing_stats_fops
= {
3545 .open
= tracing_open_generic
,
3546 .read
= tracing_stats_read
,
3549 #ifdef CONFIG_DYNAMIC_FTRACE
3551 int __weak
ftrace_arch_read_dyn_info(char *buf
, int size
)
3557 tracing_read_dyn_info(struct file
*filp
, char __user
*ubuf
,
3558 size_t cnt
, loff_t
*ppos
)
3560 static char ftrace_dyn_info_buffer
[1024];
3561 static DEFINE_MUTEX(dyn_info_mutex
);
3562 unsigned long *p
= filp
->private_data
;
3563 char *buf
= ftrace_dyn_info_buffer
;
3564 int size
= ARRAY_SIZE(ftrace_dyn_info_buffer
);
3567 mutex_lock(&dyn_info_mutex
);
3568 r
= sprintf(buf
, "%ld ", *p
);
3570 r
+= ftrace_arch_read_dyn_info(buf
+r
, (size
-1)-r
);
3573 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3575 mutex_unlock(&dyn_info_mutex
);
3580 static const struct file_operations tracing_dyn_info_fops
= {
3581 .open
= tracing_open_generic
,
3582 .read
= tracing_read_dyn_info
,
3586 static struct dentry
*d_tracer
;
3588 struct dentry
*tracing_init_dentry(void)
3595 if (!debugfs_initialized())
3598 d_tracer
= debugfs_create_dir("tracing", NULL
);
3600 if (!d_tracer
&& !once
) {
3602 pr_warning("Could not create debugfs directory 'tracing'\n");
3609 static struct dentry
*d_percpu
;
3611 struct dentry
*tracing_dentry_percpu(void)
3614 struct dentry
*d_tracer
;
3619 d_tracer
= tracing_init_dentry();
3624 d_percpu
= debugfs_create_dir("per_cpu", d_tracer
);
3626 if (!d_percpu
&& !once
) {
3628 pr_warning("Could not create debugfs directory 'per_cpu'\n");
3635 static void tracing_init_debugfs_percpu(long cpu
)
3637 struct dentry
*d_percpu
= tracing_dentry_percpu();
3638 struct dentry
*d_cpu
;
3639 /* strlen(cpu) + MAX(log10(cpu)) + '\0' */
3642 if (cpu
> 999 || cpu
< 0)
3645 sprintf(cpu_dir
, "cpu%ld", cpu
);
3646 d_cpu
= debugfs_create_dir(cpu_dir
, d_percpu
);
3648 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir
);
3652 /* per cpu trace_pipe */
3653 trace_create_file("trace_pipe", 0444, d_cpu
,
3654 (void *) cpu
, &tracing_pipe_fops
);
3657 trace_create_file("trace", 0644, d_cpu
,
3658 (void *) cpu
, &tracing_fops
);
3660 trace_create_file("trace_pipe_raw", 0444, d_cpu
,
3661 (void *) cpu
, &tracing_buffers_fops
);
3663 trace_create_file("stats", 0444, d_cpu
,
3664 (void *) cpu
, &tracing_stats_fops
);
3667 #ifdef CONFIG_FTRACE_SELFTEST
3668 /* Let selftest have access to static functions in this file */
3669 #include "trace_selftest.c"
3672 struct trace_option_dentry
{
3673 struct tracer_opt
*opt
;
3674 struct tracer_flags
*flags
;
3675 struct dentry
*entry
;
3679 trace_options_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
3682 struct trace_option_dentry
*topt
= filp
->private_data
;
3685 if (topt
->flags
->val
& topt
->opt
->bit
)
3690 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
3694 trace_options_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
3697 struct trace_option_dentry
*topt
= filp
->private_data
;
3702 if (cnt
>= sizeof(buf
))
3705 if (copy_from_user(&buf
, ubuf
, cnt
))
3710 ret
= strict_strtoul(buf
, 10, &val
);
3717 /* do nothing if already cleared */
3718 if (!(topt
->flags
->val
& topt
->opt
->bit
))
3721 mutex_lock(&trace_types_lock
);
3722 if (current_trace
->set_flag
)
3723 ret
= current_trace
->set_flag(topt
->flags
->val
,
3725 mutex_unlock(&trace_types_lock
);
3728 topt
->flags
->val
&= ~topt
->opt
->bit
;
3731 /* do nothing if already set */
3732 if (topt
->flags
->val
& topt
->opt
->bit
)
3735 mutex_lock(&trace_types_lock
);
3736 if (current_trace
->set_flag
)
3737 ret
= current_trace
->set_flag(topt
->flags
->val
,
3739 mutex_unlock(&trace_types_lock
);
3742 topt
->flags
->val
|= topt
->opt
->bit
;
3755 static const struct file_operations trace_options_fops
= {
3756 .open
= tracing_open_generic
,
3757 .read
= trace_options_read
,
3758 .write
= trace_options_write
,
3762 trace_options_core_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
3765 long index
= (long)filp
->private_data
;
3768 if (trace_flags
& (1 << index
))
3773 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
3777 trace_options_core_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
3780 long index
= (long)filp
->private_data
;
3785 if (cnt
>= sizeof(buf
))
3788 if (copy_from_user(&buf
, ubuf
, cnt
))
3793 ret
= strict_strtoul(buf
, 10, &val
);
3799 trace_flags
&= ~(1 << index
);
3802 trace_flags
|= 1 << index
;
3814 static const struct file_operations trace_options_core_fops
= {
3815 .open
= tracing_open_generic
,
3816 .read
= trace_options_core_read
,
3817 .write
= trace_options_core_write
,
3820 struct dentry
*trace_create_file(const char *name
,
3822 struct dentry
*parent
,
3824 const struct file_operations
*fops
)
3828 ret
= debugfs_create_file(name
, mode
, parent
, data
, fops
);
3830 pr_warning("Could not create debugfs '%s' entry\n", name
);
3836 static struct dentry
*trace_options_init_dentry(void)
3838 struct dentry
*d_tracer
;
3839 static struct dentry
*t_options
;
3844 d_tracer
= tracing_init_dentry();
3848 t_options
= debugfs_create_dir("options", d_tracer
);
3850 pr_warning("Could not create debugfs directory 'options'\n");
3858 create_trace_option_file(struct trace_option_dentry
*topt
,
3859 struct tracer_flags
*flags
,
3860 struct tracer_opt
*opt
)
3862 struct dentry
*t_options
;
3864 t_options
= trace_options_init_dentry();
3868 topt
->flags
= flags
;
3871 topt
->entry
= trace_create_file(opt
->name
, 0644, t_options
, topt
,
3872 &trace_options_fops
);
3876 static struct trace_option_dentry
*
3877 create_trace_option_files(struct tracer
*tracer
)
3879 struct trace_option_dentry
*topts
;
3880 struct tracer_flags
*flags
;
3881 struct tracer_opt
*opts
;
3887 flags
= tracer
->flags
;
3889 if (!flags
|| !flags
->opts
)
3894 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
3897 topts
= kcalloc(cnt
+ 1, sizeof(*topts
), GFP_KERNEL
);
3901 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
3902 create_trace_option_file(&topts
[cnt
], flags
,
3909 destroy_trace_option_files(struct trace_option_dentry
*topts
)
3916 for (cnt
= 0; topts
[cnt
].opt
; cnt
++) {
3917 if (topts
[cnt
].entry
)
3918 debugfs_remove(topts
[cnt
].entry
);
3924 static struct dentry
*
3925 create_trace_option_core_file(const char *option
, long index
)
3927 struct dentry
*t_options
;
3929 t_options
= trace_options_init_dentry();
3933 return trace_create_file(option
, 0644, t_options
, (void *)index
,
3934 &trace_options_core_fops
);
3937 static __init
void create_trace_options_dir(void)
3939 struct dentry
*t_options
;
3942 t_options
= trace_options_init_dentry();
3946 for (i
= 0; trace_options
[i
]; i
++)
3947 create_trace_option_core_file(trace_options
[i
], i
);
3950 static __init
int tracer_init_debugfs(void)
3952 struct dentry
*d_tracer
;
3955 d_tracer
= tracing_init_dentry();
3957 trace_create_file("tracing_enabled", 0644, d_tracer
,
3958 &global_trace
, &tracing_ctrl_fops
);
3960 trace_create_file("trace_options", 0644, d_tracer
,
3961 NULL
, &tracing_iter_fops
);
3963 trace_create_file("tracing_cpumask", 0644, d_tracer
,
3964 NULL
, &tracing_cpumask_fops
);
3966 trace_create_file("trace", 0644, d_tracer
,
3967 (void *) TRACE_PIPE_ALL_CPU
, &tracing_fops
);
3969 trace_create_file("available_tracers", 0444, d_tracer
,
3970 &global_trace
, &show_traces_fops
);
3972 trace_create_file("current_tracer", 0644, d_tracer
,
3973 &global_trace
, &set_tracer_fops
);
3975 #ifdef CONFIG_TRACER_MAX_TRACE
3976 trace_create_file("tracing_max_latency", 0644, d_tracer
,
3977 &tracing_max_latency
, &tracing_max_lat_fops
);
3979 trace_create_file("tracing_thresh", 0644, d_tracer
,
3980 &tracing_thresh
, &tracing_max_lat_fops
);
3983 trace_create_file("README", 0444, d_tracer
,
3984 NULL
, &tracing_readme_fops
);
3986 trace_create_file("trace_pipe", 0444, d_tracer
,
3987 (void *) TRACE_PIPE_ALL_CPU
, &tracing_pipe_fops
);
3989 trace_create_file("buffer_size_kb", 0644, d_tracer
,
3990 &global_trace
, &tracing_entries_fops
);
3992 trace_create_file("trace_marker", 0220, d_tracer
,
3993 NULL
, &tracing_mark_fops
);
3995 trace_create_file("saved_cmdlines", 0444, d_tracer
,
3996 NULL
, &tracing_saved_cmdlines_fops
);
3998 trace_create_file("trace_clock", 0644, d_tracer
, NULL
,
4001 #ifdef CONFIG_DYNAMIC_FTRACE
4002 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
4003 &ftrace_update_tot_cnt
, &tracing_dyn_info_fops
);
4005 #ifdef CONFIG_SYSPROF_TRACER
4006 init_tracer_sysprof_debugfs(d_tracer
);
4009 create_trace_options_dir();
4011 for_each_tracing_cpu(cpu
)
4012 tracing_init_debugfs_percpu(cpu
);
4017 static int trace_panic_handler(struct notifier_block
*this,
4018 unsigned long event
, void *unused
)
4020 if (ftrace_dump_on_oops
)
4025 static struct notifier_block trace_panic_notifier
= {
4026 .notifier_call
= trace_panic_handler
,
4028 .priority
= 150 /* priority: INT_MAX >= x >= 0 */
4031 static int trace_die_handler(struct notifier_block
*self
,
4037 if (ftrace_dump_on_oops
)
4046 static struct notifier_block trace_die_notifier
= {
4047 .notifier_call
= trace_die_handler
,
4052 * printk is set to max of 1024, we really don't need it that big.
4053 * Nothing should be printing 1000 characters anyway.
4055 #define TRACE_MAX_PRINT 1000
4058 * Define here KERN_TRACE so that we have one place to modify
4059 * it if we decide to change what log level the ftrace dump
4062 #define KERN_TRACE KERN_EMERG
4065 trace_printk_seq(struct trace_seq
*s
)
4067 /* Probably should print a warning here. */
4071 /* should be zero ended, but we are paranoid. */
4072 s
->buffer
[s
->len
] = 0;
4074 printk(KERN_TRACE
"%s", s
->buffer
);
4079 static void __ftrace_dump(bool disable_tracing
)
4081 static raw_spinlock_t ftrace_dump_lock
=
4082 (raw_spinlock_t
)__RAW_SPIN_LOCK_UNLOCKED
;
4083 /* use static because iter can be a bit big for the stack */
4084 static struct trace_iterator iter
;
4085 unsigned int old_userobj
;
4086 static int dump_ran
;
4087 unsigned long flags
;
4091 local_irq_save(flags
);
4092 __raw_spin_lock(&ftrace_dump_lock
);
4100 if (disable_tracing
)
4103 for_each_tracing_cpu(cpu
) {
4104 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
4107 old_userobj
= trace_flags
& TRACE_ITER_SYM_USEROBJ
;
4109 /* don't look at user memory in panic mode */
4110 trace_flags
&= ~TRACE_ITER_SYM_USEROBJ
;
4112 printk(KERN_TRACE
"Dumping ftrace buffer:\n");
4114 /* Simulate the iterator */
4115 iter
.tr
= &global_trace
;
4116 iter
.trace
= current_trace
;
4117 iter
.cpu_file
= TRACE_PIPE_ALL_CPU
;
4120 * We need to stop all tracing on all CPUS to read the
4121 * the next buffer. This is a bit expensive, but is
4122 * not done often. We fill all what we can read,
4123 * and then release the locks again.
4126 while (!trace_empty(&iter
)) {
4129 printk(KERN_TRACE
"---------------------------------\n");
4133 /* reset all but tr, trace, and overruns */
4134 memset(&iter
.seq
, 0,
4135 sizeof(struct trace_iterator
) -
4136 offsetof(struct trace_iterator
, seq
));
4137 iter
.iter_flags
|= TRACE_FILE_LAT_FMT
;
4140 if (find_next_entry_inc(&iter
) != NULL
) {
4143 ret
= print_trace_line(&iter
);
4144 if (ret
!= TRACE_TYPE_NO_CONSUME
)
4145 trace_consume(&iter
);
4148 trace_printk_seq(&iter
.seq
);
4152 printk(KERN_TRACE
" (ftrace buffer empty)\n");
4154 printk(KERN_TRACE
"---------------------------------\n");
4156 /* Re-enable tracing if requested */
4157 if (!disable_tracing
) {
4158 trace_flags
|= old_userobj
;
4160 for_each_tracing_cpu(cpu
) {
4161 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
4167 __raw_spin_unlock(&ftrace_dump_lock
);
4168 local_irq_restore(flags
);
4171 /* By default: disable tracing after the dump */
4172 void ftrace_dump(void)
4174 __ftrace_dump(true);
4177 __init
static int tracer_alloc_buffers(void)
4183 if (!alloc_cpumask_var(&tracing_buffer_mask
, GFP_KERNEL
))
4186 if (!alloc_cpumask_var(&tracing_cpumask
, GFP_KERNEL
))
4187 goto out_free_buffer_mask
;
4189 if (!alloc_cpumask_var(&tracing_reader_cpumask
, GFP_KERNEL
))
4190 goto out_free_tracing_cpumask
;
4192 /* To save memory, keep the ring buffer size to its minimum */
4193 if (ring_buffer_expanded
)
4194 ring_buf_size
= trace_buf_size
;
4198 cpumask_copy(tracing_buffer_mask
, cpu_possible_mask
);
4199 cpumask_copy(tracing_cpumask
, cpu_all_mask
);
4200 cpumask_clear(tracing_reader_cpumask
);
4202 /* TODO: make the number of buffers hot pluggable with CPUS */
4203 global_trace
.buffer
= ring_buffer_alloc(ring_buf_size
,
4204 TRACE_BUFFER_FLAGS
);
4205 if (!global_trace
.buffer
) {
4206 printk(KERN_ERR
"tracer: failed to allocate ring buffer!\n");
4208 goto out_free_cpumask
;
4210 global_trace
.entries
= ring_buffer_size(global_trace
.buffer
);
4213 #ifdef CONFIG_TRACER_MAX_TRACE
4214 max_tr
.buffer
= ring_buffer_alloc(ring_buf_size
,
4215 TRACE_BUFFER_FLAGS
);
4216 if (!max_tr
.buffer
) {
4217 printk(KERN_ERR
"tracer: failed to allocate max ring buffer!\n");
4219 ring_buffer_free(global_trace
.buffer
);
4220 goto out_free_cpumask
;
4222 max_tr
.entries
= ring_buffer_size(max_tr
.buffer
);
4223 WARN_ON(max_tr
.entries
!= global_trace
.entries
);
4226 /* Allocate the first page for all buffers */
4227 for_each_tracing_cpu(i
) {
4228 global_trace
.data
[i
] = &per_cpu(global_trace_cpu
, i
);
4229 max_tr
.data
[i
] = &per_cpu(max_data
, i
);
4232 trace_init_cmdlines();
4234 register_tracer(&nop_trace
);
4235 current_trace
= &nop_trace
;
4236 #ifdef CONFIG_BOOT_TRACER
4237 register_tracer(&boot_tracer
);
4239 /* All seems OK, enable tracing */
4240 tracing_disabled
= 0;
4242 atomic_notifier_chain_register(&panic_notifier_list
,
4243 &trace_panic_notifier
);
4245 register_die_notifier(&trace_die_notifier
);
4250 free_cpumask_var(tracing_reader_cpumask
);
4251 out_free_tracing_cpumask
:
4252 free_cpumask_var(tracing_cpumask
);
4253 out_free_buffer_mask
:
4254 free_cpumask_var(tracing_buffer_mask
);
4259 __init
static int clear_boot_tracer(void)
4262 * The default tracer at boot buffer is an init section.
4263 * This function is called in lateinit. If we did not
4264 * find the boot tracer, then clear it out, to prevent
4265 * later registration from accessing the buffer that is
4266 * about to be freed.
4268 if (!default_bootup_tracer
)
4271 printk(KERN_INFO
"ftrace bootup tracer '%s' not registered.\n",
4272 default_bootup_tracer
);
4273 default_bootup_tracer
= NULL
;
4278 early_initcall(tracer_alloc_buffers
);
4279 fs_initcall(tracer_init_debugfs
);
4280 late_initcall(clear_boot_tracer
);