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/ctype.h>
34 #include <linux/init.h>
35 #include <linux/poll.h>
36 #include <linux/gfp.h>
40 #include "trace_output.h"
42 #define TRACE_BUFFER_FLAGS (RB_FL_OVERWRITE)
44 unsigned long __read_mostly tracing_max_latency
;
45 unsigned long __read_mostly tracing_thresh
;
48 * On boot up, the ring buffer is set to the minimum size, so that
49 * we do not waste memory on systems that are not using tracing.
51 static int ring_buffer_expanded
;
54 * We need to change this state when a selftest is running.
55 * A selftest will lurk into the ring-buffer to count the
56 * entries inserted during the selftest although some concurrent
57 * insertions into the ring-buffer such as trace_printk could occurred
58 * at the same time, giving false positive or negative results.
60 static bool __read_mostly tracing_selftest_running
;
63 * If a tracer is running, we do not want to run SELFTEST.
65 static bool __read_mostly tracing_selftest_disabled
;
67 /* For tracers that don't implement custom flags */
68 static struct tracer_opt dummy_tracer_opt
[] = {
72 static struct tracer_flags dummy_tracer_flags
= {
74 .opts
= dummy_tracer_opt
77 static int dummy_set_flag(u32 old_flags
, u32 bit
, int set
)
83 * Kill all tracing for good (never come back).
84 * It is initialized to 1 but will turn to zero if the initialization
85 * of the tracer is successful. But that is the only place that sets
88 static int tracing_disabled
= 1;
90 static DEFINE_PER_CPU(local_t
, ftrace_cpu_disabled
);
92 static inline void ftrace_disable_cpu(void)
95 local_inc(&__get_cpu_var(ftrace_cpu_disabled
));
98 static inline void ftrace_enable_cpu(void)
100 local_dec(&__get_cpu_var(ftrace_cpu_disabled
));
104 static cpumask_var_t __read_mostly tracing_buffer_mask
;
106 /* Define which cpu buffers are currently read in trace_pipe */
107 static cpumask_var_t tracing_reader_cpumask
;
109 #define for_each_tracing_cpu(cpu) \
110 for_each_cpu(cpu, tracing_buffer_mask)
113 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
115 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
116 * is set, then ftrace_dump is called. This will output the contents
117 * of the ftrace buffers to the console. This is very useful for
118 * capturing traces that lead to crashes and outputing it to a
121 * It is default off, but you can enable it with either specifying
122 * "ftrace_dump_on_oops" in the kernel command line, or setting
123 * /proc/sys/kernel/ftrace_dump_on_oops to true.
125 int ftrace_dump_on_oops
;
127 static int tracing_set_tracer(const char *buf
);
129 #define BOOTUP_TRACER_SIZE 100
130 static char bootup_tracer_buf
[BOOTUP_TRACER_SIZE
] __initdata
;
131 static char *default_bootup_tracer
;
133 static int __init
set_ftrace(char *str
)
135 strncpy(bootup_tracer_buf
, str
, BOOTUP_TRACER_SIZE
);
136 default_bootup_tracer
= bootup_tracer_buf
;
137 /* We are using ftrace early, expand it */
138 ring_buffer_expanded
= 1;
141 __setup("ftrace=", set_ftrace
);
143 static int __init
set_ftrace_dump_on_oops(char *str
)
145 ftrace_dump_on_oops
= 1;
148 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops
);
151 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 cycle_t
ftrace_now(int cpu
)
178 /* Early boot up does not have a buffer yet */
179 if (!global_trace
.buffer
)
180 return trace_clock_local();
182 ts
= ring_buffer_time_stamp(global_trace
.buffer
, cpu
);
183 ring_buffer_normalize_time_stamp(global_trace
.buffer
, cpu
, &ts
);
189 * The max_tr is used to snapshot the global_trace when a maximum
190 * latency is reached. Some tracers will use this to store a maximum
191 * trace while it continues examining live traces.
193 * The buffers for the max_tr are set up the same as the global_trace.
194 * When a snapshot is taken, the link list of the max_tr is swapped
195 * with the link list of the global_trace and the buffers are reset for
196 * the global_trace so the tracing can continue.
198 static struct trace_array max_tr
;
200 static DEFINE_PER_CPU(struct trace_array_cpu
, max_data
);
202 /* tracer_enabled is used to toggle activation of a tracer */
203 static int tracer_enabled
= 1;
206 * tracing_is_enabled - return tracer_enabled status
208 * This function is used by other tracers to know the status
209 * of the tracer_enabled flag. Tracers may use this function
210 * to know if it should enable their features when starting
211 * up. See irqsoff tracer for an example (start_irqsoff_tracer).
213 int tracing_is_enabled(void)
215 return tracer_enabled
;
219 * trace_buf_size is the size in bytes that is allocated
220 * for a buffer. Note, the number of bytes is always rounded
223 * This number is purposely set to a low number of 16384.
224 * If the dump on oops happens, it will be much appreciated
225 * to not have to wait for all that output. Anyway this can be
226 * boot time and run time configurable.
228 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
230 static unsigned long trace_buf_size
= TRACE_BUF_SIZE_DEFAULT
;
232 /* trace_types holds a link list of available tracers. */
233 static struct tracer
*trace_types __read_mostly
;
235 /* current_trace points to the tracer that is currently active */
236 static struct tracer
*current_trace __read_mostly
;
239 * max_tracer_type_len is used to simplify the allocating of
240 * buffers to read userspace tracer names. We keep track of
241 * the longest tracer name registered.
243 static int max_tracer_type_len
;
246 * trace_types_lock is used to protect the trace_types list.
247 * This lock is also used to keep user access serialized.
248 * Accesses from userspace will grab this lock while userspace
249 * activities happen inside the kernel.
251 static DEFINE_MUTEX(trace_types_lock
);
253 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
254 static DECLARE_WAIT_QUEUE_HEAD(trace_wait
);
256 /* trace_flags holds trace_options default values */
257 unsigned long trace_flags
= TRACE_ITER_PRINT_PARENT
| TRACE_ITER_PRINTK
|
258 TRACE_ITER_ANNOTATE
| TRACE_ITER_CONTEXT_INFO
;
261 * trace_wake_up - wake up tasks waiting for trace input
263 * Simply wakes up any task that is blocked on the trace_wait
264 * queue. These is used with trace_poll for tasks polling the trace.
266 void trace_wake_up(void)
269 * The runqueue_is_locked() can fail, but this is the best we
272 if (!(trace_flags
& TRACE_ITER_BLOCK
) && !runqueue_is_locked())
273 wake_up(&trace_wait
);
276 static int __init
set_buf_size(char *str
)
278 unsigned long buf_size
;
283 ret
= strict_strtoul(str
, 0, &buf_size
);
284 /* nr_entries can not be zero */
285 if (ret
< 0 || buf_size
== 0)
287 trace_buf_size
= buf_size
;
290 __setup("trace_buf_size=", set_buf_size
);
292 unsigned long nsecs_to_usecs(unsigned long nsecs
)
297 /* These must match the bit postions in trace_iterator_flags */
298 static const char *trace_options
[] = {
323 * ftrace_max_lock is used to protect the swapping of buffers
324 * when taking a max snapshot. The buffers themselves are
325 * protected by per_cpu spinlocks. But the action of the swap
326 * needs its own lock.
328 * This is defined as a raw_spinlock_t in order to help
329 * with performance when lockdep debugging is enabled.
331 static raw_spinlock_t ftrace_max_lock
=
332 (raw_spinlock_t
)__RAW_SPIN_LOCK_UNLOCKED
;
335 * Copy the new maximum trace into the separate maximum-trace
336 * structure. (this way the maximum trace is permanently saved,
337 * for later retrieval via /debugfs/tracing/latency_trace)
340 __update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
342 struct trace_array_cpu
*data
= tr
->data
[cpu
];
345 max_tr
.time_start
= data
->preempt_timestamp
;
347 data
= max_tr
.data
[cpu
];
348 data
->saved_latency
= tracing_max_latency
;
350 memcpy(data
->comm
, tsk
->comm
, TASK_COMM_LEN
);
351 data
->pid
= tsk
->pid
;
352 data
->uid
= task_uid(tsk
);
353 data
->nice
= tsk
->static_prio
- 20 - MAX_RT_PRIO
;
354 data
->policy
= tsk
->policy
;
355 data
->rt_priority
= tsk
->rt_priority
;
357 /* record this tasks comm */
358 tracing_record_cmdline(tsk
);
361 ssize_t
trace_seq_to_user(struct trace_seq
*s
, char __user
*ubuf
, size_t cnt
)
369 if (s
->len
<= s
->readpos
)
372 len
= s
->len
- s
->readpos
;
375 ret
= copy_to_user(ubuf
, s
->buffer
+ s
->readpos
, cnt
);
385 ssize_t
trace_seq_to_buffer(struct trace_seq
*s
, void *buf
, size_t cnt
)
390 if (s
->len
<= s
->readpos
)
393 len
= s
->len
- s
->readpos
;
396 ret
= memcpy(buf
, s
->buffer
+ s
->readpos
, cnt
);
405 trace_print_seq(struct seq_file
*m
, struct trace_seq
*s
)
407 int len
= s
->len
>= PAGE_SIZE
? PAGE_SIZE
- 1 : s
->len
;
410 seq_puts(m
, s
->buffer
);
416 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
418 * @tsk: the task with the latency
419 * @cpu: The cpu that initiated the trace.
421 * Flip the buffers between the @tr and the max_tr and record information
422 * about which task was the cause of this latency.
425 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
427 struct ring_buffer
*buf
= tr
->buffer
;
429 WARN_ON_ONCE(!irqs_disabled());
430 __raw_spin_lock(&ftrace_max_lock
);
432 tr
->buffer
= max_tr
.buffer
;
435 ftrace_disable_cpu();
436 ring_buffer_reset(tr
->buffer
);
439 __update_max_tr(tr
, tsk
, cpu
);
440 __raw_spin_unlock(&ftrace_max_lock
);
444 * update_max_tr_single - only copy one trace over, and reset the rest
446 * @tsk - task with the latency
447 * @cpu - the cpu of the buffer to copy.
449 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
452 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
456 WARN_ON_ONCE(!irqs_disabled());
457 __raw_spin_lock(&ftrace_max_lock
);
459 ftrace_disable_cpu();
461 ring_buffer_reset(max_tr
.buffer
);
462 ret
= ring_buffer_swap_cpu(max_tr
.buffer
, tr
->buffer
, cpu
);
466 WARN_ON_ONCE(ret
&& ret
!= -EAGAIN
);
468 __update_max_tr(tr
, tsk
, cpu
);
469 __raw_spin_unlock(&ftrace_max_lock
);
473 * register_tracer - register a tracer with the ftrace system.
474 * @type - the plugin for the tracer
476 * Register a new plugin tracer.
478 int register_tracer(struct tracer
*type
)
479 __releases(kernel_lock
)
480 __acquires(kernel_lock
)
487 pr_info("Tracer must have a name\n");
492 * When this gets called we hold the BKL which means that
493 * preemption is disabled. Various trace selftests however
494 * need to disable and enable preemption for successful tests.
495 * So we drop the BKL here and grab it after the tests again.
498 mutex_lock(&trace_types_lock
);
500 tracing_selftest_running
= true;
502 for (t
= trace_types
; t
; t
= t
->next
) {
503 if (strcmp(type
->name
, t
->name
) == 0) {
505 pr_info("Trace %s already registered\n",
513 type
->set_flag
= &dummy_set_flag
;
515 type
->flags
= &dummy_tracer_flags
;
517 if (!type
->flags
->opts
)
518 type
->flags
->opts
= dummy_tracer_opt
;
519 if (!type
->wait_pipe
)
520 type
->wait_pipe
= default_wait_pipe
;
523 #ifdef CONFIG_FTRACE_STARTUP_TEST
524 if (type
->selftest
&& !tracing_selftest_disabled
) {
525 struct tracer
*saved_tracer
= current_trace
;
526 struct trace_array
*tr
= &global_trace
;
530 * Run a selftest on this tracer.
531 * Here we reset the trace buffer, and set the current
532 * tracer to be this tracer. The tracer can then run some
533 * internal tracing to verify that everything is in order.
534 * If we fail, we do not register this tracer.
536 for_each_tracing_cpu(i
)
537 tracing_reset(tr
, i
);
539 current_trace
= type
;
540 /* the test is responsible for initializing and enabling */
541 pr_info("Testing tracer %s: ", type
->name
);
542 ret
= type
->selftest(type
, tr
);
543 /* the test is responsible for resetting too */
544 current_trace
= saved_tracer
;
546 printk(KERN_CONT
"FAILED!\n");
549 /* Only reset on passing, to avoid touching corrupted buffers */
550 for_each_tracing_cpu(i
)
551 tracing_reset(tr
, i
);
553 printk(KERN_CONT
"PASSED\n");
557 type
->next
= trace_types
;
559 len
= strlen(type
->name
);
560 if (len
> max_tracer_type_len
)
561 max_tracer_type_len
= len
;
564 tracing_selftest_running
= false;
565 mutex_unlock(&trace_types_lock
);
567 if (ret
|| !default_bootup_tracer
)
570 if (strncmp(default_bootup_tracer
, type
->name
, BOOTUP_TRACER_SIZE
))
573 printk(KERN_INFO
"Starting tracer '%s'\n", type
->name
);
574 /* Do we want this tracer to start on bootup? */
575 tracing_set_tracer(type
->name
);
576 default_bootup_tracer
= NULL
;
577 /* disable other selftests, since this will break it. */
578 tracing_selftest_disabled
= 1;
579 #ifdef CONFIG_FTRACE_STARTUP_TEST
580 printk(KERN_INFO
"Disabling FTRACE selftests due to running tracer '%s'\n",
589 void unregister_tracer(struct tracer
*type
)
594 mutex_lock(&trace_types_lock
);
595 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
599 pr_info("Trace %s not registered\n", type
->name
);
605 if (type
== current_trace
&& tracer_enabled
) {
608 if (current_trace
->stop
)
609 current_trace
->stop(&global_trace
);
610 current_trace
= &nop_trace
;
613 if (strlen(type
->name
) != max_tracer_type_len
)
616 max_tracer_type_len
= 0;
617 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
618 len
= strlen((*t
)->name
);
619 if (len
> max_tracer_type_len
)
620 max_tracer_type_len
= len
;
623 mutex_unlock(&trace_types_lock
);
626 void tracing_reset(struct trace_array
*tr
, int cpu
)
628 ftrace_disable_cpu();
629 ring_buffer_reset_cpu(tr
->buffer
, cpu
);
633 void tracing_reset_online_cpus(struct trace_array
*tr
)
637 tr
->time_start
= ftrace_now(tr
->cpu
);
639 for_each_online_cpu(cpu
)
640 tracing_reset(tr
, cpu
);
643 #define SAVED_CMDLINES 128
644 #define NO_CMDLINE_MAP UINT_MAX
645 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
646 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
647 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
648 static int cmdline_idx
;
649 static raw_spinlock_t trace_cmdline_lock
= __RAW_SPIN_LOCK_UNLOCKED
;
651 /* temporary disable recording */
652 static atomic_t trace_record_cmdline_disabled __read_mostly
;
654 static void trace_init_cmdlines(void)
656 memset(&map_pid_to_cmdline
, NO_CMDLINE_MAP
, sizeof(map_pid_to_cmdline
));
657 memset(&map_cmdline_to_pid
, NO_CMDLINE_MAP
, sizeof(map_cmdline_to_pid
));
661 static int trace_stop_count
;
662 static DEFINE_SPINLOCK(tracing_start_lock
);
665 * ftrace_off_permanent - disable all ftrace code permanently
667 * This should only be called when a serious anomally has
668 * been detected. This will turn off the function tracing,
669 * ring buffers, and other tracing utilites. It takes no
670 * locks and can be called from any context.
672 void ftrace_off_permanent(void)
674 tracing_disabled
= 1;
676 tracing_off_permanent();
680 * tracing_start - quick start of the tracer
682 * If tracing is enabled but was stopped by tracing_stop,
683 * this will start the tracer back up.
685 void tracing_start(void)
687 struct ring_buffer
*buffer
;
690 if (tracing_disabled
)
693 spin_lock_irqsave(&tracing_start_lock
, flags
);
694 if (--trace_stop_count
) {
695 if (trace_stop_count
< 0) {
696 /* Someone screwed up their debugging */
698 trace_stop_count
= 0;
704 buffer
= global_trace
.buffer
;
706 ring_buffer_record_enable(buffer
);
708 buffer
= max_tr
.buffer
;
710 ring_buffer_record_enable(buffer
);
714 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
718 * tracing_stop - quick stop of the tracer
720 * Light weight way to stop tracing. Use in conjunction with
723 void tracing_stop(void)
725 struct ring_buffer
*buffer
;
729 spin_lock_irqsave(&tracing_start_lock
, flags
);
730 if (trace_stop_count
++)
733 buffer
= global_trace
.buffer
;
735 ring_buffer_record_disable(buffer
);
737 buffer
= max_tr
.buffer
;
739 ring_buffer_record_disable(buffer
);
742 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
745 void trace_stop_cmdline_recording(void);
747 static void trace_save_cmdline(struct task_struct
*tsk
)
751 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
755 * It's not the end of the world if we don't get
756 * the lock, but we also don't want to spin
757 * nor do we want to disable interrupts,
758 * so if we miss here, then better luck next time.
760 if (!__raw_spin_trylock(&trace_cmdline_lock
))
763 idx
= map_pid_to_cmdline
[tsk
->pid
];
764 if (idx
== NO_CMDLINE_MAP
) {
765 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
768 * Check whether the cmdline buffer at idx has a pid
769 * mapped. We are going to overwrite that entry so we
770 * need to clear the map_pid_to_cmdline. Otherwise we
771 * would read the new comm for the old pid.
773 pid
= map_cmdline_to_pid
[idx
];
774 if (pid
!= NO_CMDLINE_MAP
)
775 map_pid_to_cmdline
[pid
] = NO_CMDLINE_MAP
;
777 map_cmdline_to_pid
[idx
] = tsk
->pid
;
778 map_pid_to_cmdline
[tsk
->pid
] = idx
;
783 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
785 __raw_spin_unlock(&trace_cmdline_lock
);
788 void trace_find_cmdline(int pid
, char comm
[])
793 strcpy(comm
, "<idle>");
797 if (pid
> PID_MAX_DEFAULT
) {
798 strcpy(comm
, "<...>");
802 __raw_spin_lock(&trace_cmdline_lock
);
803 map
= map_pid_to_cmdline
[pid
];
804 if (map
!= NO_CMDLINE_MAP
)
805 strcpy(comm
, saved_cmdlines
[map
]);
807 strcpy(comm
, "<...>");
809 __raw_spin_unlock(&trace_cmdline_lock
);
812 void tracing_record_cmdline(struct task_struct
*tsk
)
814 if (atomic_read(&trace_record_cmdline_disabled
) || !tracer_enabled
||
818 trace_save_cmdline(tsk
);
822 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
,
825 struct task_struct
*tsk
= current
;
827 entry
->preempt_count
= pc
& 0xff;
828 entry
->pid
= (tsk
) ? tsk
->pid
: 0;
829 entry
->tgid
= (tsk
) ? tsk
->tgid
: 0;
831 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
832 (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
834 TRACE_FLAG_IRQS_NOSUPPORT
|
836 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
837 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
838 (need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0);
841 struct ring_buffer_event
*trace_buffer_lock_reserve(struct trace_array
*tr
,
844 unsigned long flags
, int pc
)
846 struct ring_buffer_event
*event
;
848 event
= ring_buffer_lock_reserve(tr
->buffer
, len
);
850 struct trace_entry
*ent
= ring_buffer_event_data(event
);
852 tracing_generic_entry_update(ent
, flags
, pc
);
858 static void ftrace_trace_stack(struct trace_array
*tr
,
859 unsigned long flags
, int skip
, int pc
);
860 static void ftrace_trace_userstack(struct trace_array
*tr
,
861 unsigned long flags
, int pc
);
863 void trace_buffer_unlock_commit(struct trace_array
*tr
,
864 struct ring_buffer_event
*event
,
865 unsigned long flags
, int pc
)
867 ring_buffer_unlock_commit(tr
->buffer
, event
);
869 ftrace_trace_stack(tr
, flags
, 6, pc
);
870 ftrace_trace_userstack(tr
, flags
, pc
);
874 struct ring_buffer_event
*
875 trace_current_buffer_lock_reserve(unsigned char type
, unsigned long len
,
876 unsigned long flags
, int pc
)
878 return trace_buffer_lock_reserve(&global_trace
,
879 type
, len
, flags
, pc
);
882 void trace_current_buffer_unlock_commit(struct ring_buffer_event
*event
,
883 unsigned long flags
, int pc
)
885 return trace_buffer_unlock_commit(&global_trace
, event
, flags
, pc
);
889 trace_function(struct trace_array
*tr
,
890 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
893 struct ring_buffer_event
*event
;
894 struct ftrace_entry
*entry
;
896 /* If we are reading the ring buffer, don't trace */
897 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
900 event
= trace_buffer_lock_reserve(tr
, TRACE_FN
, sizeof(*entry
),
904 entry
= ring_buffer_event_data(event
);
906 entry
->parent_ip
= parent_ip
;
907 ring_buffer_unlock_commit(tr
->buffer
, event
);
910 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
911 static void __trace_graph_entry(struct trace_array
*tr
,
912 struct ftrace_graph_ent
*trace
,
916 struct ring_buffer_event
*event
;
917 struct ftrace_graph_ent_entry
*entry
;
919 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
922 event
= trace_buffer_lock_reserve(&global_trace
, TRACE_GRAPH_ENT
,
923 sizeof(*entry
), flags
, pc
);
926 entry
= ring_buffer_event_data(event
);
927 entry
->graph_ent
= *trace
;
928 ring_buffer_unlock_commit(global_trace
.buffer
, event
);
931 static void __trace_graph_return(struct trace_array
*tr
,
932 struct ftrace_graph_ret
*trace
,
936 struct ring_buffer_event
*event
;
937 struct ftrace_graph_ret_entry
*entry
;
939 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
942 event
= trace_buffer_lock_reserve(&global_trace
, TRACE_GRAPH_RET
,
943 sizeof(*entry
), flags
, pc
);
946 entry
= ring_buffer_event_data(event
);
948 ring_buffer_unlock_commit(global_trace
.buffer
, event
);
953 ftrace(struct trace_array
*tr
, struct trace_array_cpu
*data
,
954 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
957 if (likely(!atomic_read(&data
->disabled
)))
958 trace_function(tr
, ip
, parent_ip
, flags
, pc
);
961 static void __ftrace_trace_stack(struct trace_array
*tr
,
965 #ifdef CONFIG_STACKTRACE
966 struct ring_buffer_event
*event
;
967 struct stack_entry
*entry
;
968 struct stack_trace trace
;
970 event
= trace_buffer_lock_reserve(tr
, TRACE_STACK
,
971 sizeof(*entry
), flags
, pc
);
974 entry
= ring_buffer_event_data(event
);
975 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
977 trace
.nr_entries
= 0;
978 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
980 trace
.entries
= entry
->caller
;
982 save_stack_trace(&trace
);
983 ring_buffer_unlock_commit(tr
->buffer
, event
);
987 static void ftrace_trace_stack(struct trace_array
*tr
,
991 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
994 __ftrace_trace_stack(tr
, flags
, skip
, pc
);
997 void __trace_stack(struct trace_array
*tr
,
1001 __ftrace_trace_stack(tr
, flags
, skip
, pc
);
1004 static void ftrace_trace_userstack(struct trace_array
*tr
,
1005 unsigned long flags
, int pc
)
1007 #ifdef CONFIG_STACKTRACE
1008 struct ring_buffer_event
*event
;
1009 struct userstack_entry
*entry
;
1010 struct stack_trace trace
;
1012 if (!(trace_flags
& TRACE_ITER_USERSTACKTRACE
))
1015 event
= trace_buffer_lock_reserve(tr
, TRACE_USER_STACK
,
1016 sizeof(*entry
), flags
, pc
);
1019 entry
= ring_buffer_event_data(event
);
1021 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
1023 trace
.nr_entries
= 0;
1024 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1026 trace
.entries
= entry
->caller
;
1028 save_stack_trace_user(&trace
);
1029 ring_buffer_unlock_commit(tr
->buffer
, event
);
1034 static void __trace_userstack(struct trace_array
*tr
, unsigned long flags
)
1036 ftrace_trace_userstack(tr
, flags
, preempt_count());
1041 ftrace_trace_special(void *__tr
,
1042 unsigned long arg1
, unsigned long arg2
, unsigned long arg3
,
1045 struct ring_buffer_event
*event
;
1046 struct trace_array
*tr
= __tr
;
1047 struct special_entry
*entry
;
1049 event
= trace_buffer_lock_reserve(tr
, TRACE_SPECIAL
,
1050 sizeof(*entry
), 0, pc
);
1053 entry
= ring_buffer_event_data(event
);
1057 trace_buffer_unlock_commit(tr
, event
, 0, pc
);
1061 __trace_special(void *__tr
, void *__data
,
1062 unsigned long arg1
, unsigned long arg2
, unsigned long arg3
)
1064 ftrace_trace_special(__tr
, arg1
, arg2
, arg3
, preempt_count());
1068 tracing_sched_switch_trace(struct trace_array
*tr
,
1069 struct task_struct
*prev
,
1070 struct task_struct
*next
,
1071 unsigned long flags
, int pc
)
1073 struct ring_buffer_event
*event
;
1074 struct ctx_switch_entry
*entry
;
1076 event
= trace_buffer_lock_reserve(tr
, TRACE_CTX
,
1077 sizeof(*entry
), flags
, pc
);
1080 entry
= ring_buffer_event_data(event
);
1081 entry
->prev_pid
= prev
->pid
;
1082 entry
->prev_prio
= prev
->prio
;
1083 entry
->prev_state
= prev
->state
;
1084 entry
->next_pid
= next
->pid
;
1085 entry
->next_prio
= next
->prio
;
1086 entry
->next_state
= next
->state
;
1087 entry
->next_cpu
= task_cpu(next
);
1088 trace_buffer_unlock_commit(tr
, event
, flags
, pc
);
1092 tracing_sched_wakeup_trace(struct trace_array
*tr
,
1093 struct task_struct
*wakee
,
1094 struct task_struct
*curr
,
1095 unsigned long flags
, int pc
)
1097 struct ring_buffer_event
*event
;
1098 struct ctx_switch_entry
*entry
;
1100 event
= trace_buffer_lock_reserve(tr
, TRACE_WAKE
,
1101 sizeof(*entry
), flags
, pc
);
1104 entry
= ring_buffer_event_data(event
);
1105 entry
->prev_pid
= curr
->pid
;
1106 entry
->prev_prio
= curr
->prio
;
1107 entry
->prev_state
= curr
->state
;
1108 entry
->next_pid
= wakee
->pid
;
1109 entry
->next_prio
= wakee
->prio
;
1110 entry
->next_state
= wakee
->state
;
1111 entry
->next_cpu
= task_cpu(wakee
);
1113 ring_buffer_unlock_commit(tr
->buffer
, event
);
1114 ftrace_trace_stack(tr
, flags
, 6, pc
);
1115 ftrace_trace_userstack(tr
, flags
, pc
);
1119 ftrace_special(unsigned long arg1
, unsigned long arg2
, unsigned long arg3
)
1121 struct trace_array
*tr
= &global_trace
;
1122 struct trace_array_cpu
*data
;
1123 unsigned long flags
;
1127 if (tracing_disabled
)
1130 pc
= preempt_count();
1131 local_irq_save(flags
);
1132 cpu
= raw_smp_processor_id();
1133 data
= tr
->data
[cpu
];
1135 if (likely(atomic_inc_return(&data
->disabled
) == 1))
1136 ftrace_trace_special(tr
, arg1
, arg2
, arg3
, pc
);
1138 atomic_dec(&data
->disabled
);
1139 local_irq_restore(flags
);
1142 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1143 int trace_graph_entry(struct ftrace_graph_ent
*trace
)
1145 struct trace_array
*tr
= &global_trace
;
1146 struct trace_array_cpu
*data
;
1147 unsigned long flags
;
1152 if (!ftrace_trace_task(current
))
1155 if (!ftrace_graph_addr(trace
->func
))
1158 local_irq_save(flags
);
1159 cpu
= raw_smp_processor_id();
1160 data
= tr
->data
[cpu
];
1161 disabled
= atomic_inc_return(&data
->disabled
);
1162 if (likely(disabled
== 1)) {
1163 pc
= preempt_count();
1164 __trace_graph_entry(tr
, trace
, flags
, pc
);
1166 /* Only do the atomic if it is not already set */
1167 if (!test_tsk_trace_graph(current
))
1168 set_tsk_trace_graph(current
);
1169 atomic_dec(&data
->disabled
);
1170 local_irq_restore(flags
);
1175 void trace_graph_return(struct ftrace_graph_ret
*trace
)
1177 struct trace_array
*tr
= &global_trace
;
1178 struct trace_array_cpu
*data
;
1179 unsigned long flags
;
1184 local_irq_save(flags
);
1185 cpu
= raw_smp_processor_id();
1186 data
= tr
->data
[cpu
];
1187 disabled
= atomic_inc_return(&data
->disabled
);
1188 if (likely(disabled
== 1)) {
1189 pc
= preempt_count();
1190 __trace_graph_return(tr
, trace
, flags
, pc
);
1193 clear_tsk_trace_graph(current
);
1194 atomic_dec(&data
->disabled
);
1195 local_irq_restore(flags
);
1197 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1201 * trace_vbprintk - write binary msg to tracing buffer
1204 int trace_vbprintk(unsigned long ip
, int depth
, const char *fmt
, va_list args
)
1206 static raw_spinlock_t trace_buf_lock
=
1207 (raw_spinlock_t
)__RAW_SPIN_LOCK_UNLOCKED
;
1208 static u32 trace_buf
[TRACE_BUF_SIZE
];
1210 struct ring_buffer_event
*event
;
1211 struct trace_array
*tr
= &global_trace
;
1212 struct trace_array_cpu
*data
;
1213 struct bprint_entry
*entry
;
1214 unsigned long flags
;
1216 int cpu
, len
= 0, size
, pc
;
1218 if (unlikely(tracing_selftest_running
|| tracing_disabled
))
1221 /* Don't pollute graph traces with trace_vprintk internals */
1222 pause_graph_tracing();
1224 pc
= preempt_count();
1225 resched
= ftrace_preempt_disable();
1226 cpu
= raw_smp_processor_id();
1227 data
= tr
->data
[cpu
];
1229 if (unlikely(atomic_read(&data
->disabled
)))
1232 /* Lockdep uses trace_printk for lock tracing */
1233 local_irq_save(flags
);
1234 __raw_spin_lock(&trace_buf_lock
);
1235 len
= vbin_printf(trace_buf
, TRACE_BUF_SIZE
, fmt
, args
);
1237 if (len
> TRACE_BUF_SIZE
|| len
< 0)
1240 size
= sizeof(*entry
) + sizeof(u32
) * len
;
1241 event
= trace_buffer_lock_reserve(tr
, TRACE_BPRINT
, size
, flags
, pc
);
1244 entry
= ring_buffer_event_data(event
);
1246 entry
->depth
= depth
;
1249 memcpy(entry
->buf
, trace_buf
, sizeof(u32
) * len
);
1250 ring_buffer_unlock_commit(tr
->buffer
, event
);
1253 __raw_spin_unlock(&trace_buf_lock
);
1254 local_irq_restore(flags
);
1257 ftrace_preempt_enable(resched
);
1258 unpause_graph_tracing();
1262 EXPORT_SYMBOL_GPL(trace_vbprintk
);
1264 int trace_vprintk(unsigned long ip
, int depth
, const char *fmt
, va_list args
)
1266 static raw_spinlock_t trace_buf_lock
= __RAW_SPIN_LOCK_UNLOCKED
;
1267 static char trace_buf
[TRACE_BUF_SIZE
];
1269 struct ring_buffer_event
*event
;
1270 struct trace_array
*tr
= &global_trace
;
1271 struct trace_array_cpu
*data
;
1272 int cpu
, len
= 0, size
, pc
;
1273 struct print_entry
*entry
;
1274 unsigned long irq_flags
;
1276 if (tracing_disabled
|| tracing_selftest_running
)
1279 pc
= preempt_count();
1280 preempt_disable_notrace();
1281 cpu
= raw_smp_processor_id();
1282 data
= tr
->data
[cpu
];
1284 if (unlikely(atomic_read(&data
->disabled
)))
1287 pause_graph_tracing();
1288 raw_local_irq_save(irq_flags
);
1289 __raw_spin_lock(&trace_buf_lock
);
1290 len
= vsnprintf(trace_buf
, TRACE_BUF_SIZE
, fmt
, args
);
1292 len
= min(len
, TRACE_BUF_SIZE
-1);
1295 size
= sizeof(*entry
) + len
+ 1;
1296 event
= trace_buffer_lock_reserve(tr
, TRACE_PRINT
, size
, irq_flags
, pc
);
1299 entry
= ring_buffer_event_data(event
);
1301 entry
->depth
= depth
;
1303 memcpy(&entry
->buf
, trace_buf
, len
);
1304 entry
->buf
[len
] = 0;
1305 ring_buffer_unlock_commit(tr
->buffer
, event
);
1308 __raw_spin_unlock(&trace_buf_lock
);
1309 raw_local_irq_restore(irq_flags
);
1310 unpause_graph_tracing();
1312 preempt_enable_notrace();
1316 EXPORT_SYMBOL_GPL(trace_vprintk
);
1318 enum trace_file_type
{
1319 TRACE_FILE_LAT_FMT
= 1,
1320 TRACE_FILE_ANNOTATE
= 2,
1323 static void trace_iterator_increment(struct trace_iterator
*iter
)
1325 /* Don't allow ftrace to trace into the ring buffers */
1326 ftrace_disable_cpu();
1329 if (iter
->buffer_iter
[iter
->cpu
])
1330 ring_buffer_read(iter
->buffer_iter
[iter
->cpu
], NULL
);
1332 ftrace_enable_cpu();
1335 static struct trace_entry
*
1336 peek_next_entry(struct trace_iterator
*iter
, int cpu
, u64
*ts
)
1338 struct ring_buffer_event
*event
;
1339 struct ring_buffer_iter
*buf_iter
= iter
->buffer_iter
[cpu
];
1341 /* Don't allow ftrace to trace into the ring buffers */
1342 ftrace_disable_cpu();
1345 event
= ring_buffer_iter_peek(buf_iter
, ts
);
1347 event
= ring_buffer_peek(iter
->tr
->buffer
, cpu
, ts
);
1349 ftrace_enable_cpu();
1351 return event
? ring_buffer_event_data(event
) : NULL
;
1354 static struct trace_entry
*
1355 __find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
, u64
*ent_ts
)
1357 struct ring_buffer
*buffer
= iter
->tr
->buffer
;
1358 struct trace_entry
*ent
, *next
= NULL
;
1359 int cpu_file
= iter
->cpu_file
;
1360 u64 next_ts
= 0, ts
;
1365 * If we are in a per_cpu trace file, don't bother by iterating over
1366 * all cpu and peek directly.
1368 if (cpu_file
> TRACE_PIPE_ALL_CPU
) {
1369 if (ring_buffer_empty_cpu(buffer
, cpu_file
))
1371 ent
= peek_next_entry(iter
, cpu_file
, ent_ts
);
1373 *ent_cpu
= cpu_file
;
1378 for_each_tracing_cpu(cpu
) {
1380 if (ring_buffer_empty_cpu(buffer
, cpu
))
1383 ent
= peek_next_entry(iter
, cpu
, &ts
);
1386 * Pick the entry with the smallest timestamp:
1388 if (ent
&& (!next
|| ts
< next_ts
)) {
1396 *ent_cpu
= next_cpu
;
1404 /* Find the next real entry, without updating the iterator itself */
1405 struct trace_entry
*trace_find_next_entry(struct trace_iterator
*iter
,
1406 int *ent_cpu
, u64
*ent_ts
)
1408 return __find_next_entry(iter
, ent_cpu
, ent_ts
);
1411 /* Find the next real entry, and increment the iterator to the next entry */
1412 static void *find_next_entry_inc(struct trace_iterator
*iter
)
1414 iter
->ent
= __find_next_entry(iter
, &iter
->cpu
, &iter
->ts
);
1417 trace_iterator_increment(iter
);
1419 return iter
->ent
? iter
: NULL
;
1422 static void trace_consume(struct trace_iterator
*iter
)
1424 /* Don't allow ftrace to trace into the ring buffers */
1425 ftrace_disable_cpu();
1426 ring_buffer_consume(iter
->tr
->buffer
, iter
->cpu
, &iter
->ts
);
1427 ftrace_enable_cpu();
1430 static void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1432 struct trace_iterator
*iter
= m
->private;
1438 /* can't go backwards */
1443 ent
= find_next_entry_inc(iter
);
1447 while (ent
&& iter
->idx
< i
)
1448 ent
= find_next_entry_inc(iter
);
1456 * No necessary locking here. The worst thing which can
1457 * happen is loosing events consumed at the same time
1458 * by a trace_pipe reader.
1459 * Other than that, we don't risk to crash the ring buffer
1460 * because it serializes the readers.
1462 * The current tracer is copied to avoid a global locking
1465 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
1467 struct trace_iterator
*iter
= m
->private;
1468 static struct tracer
*old_tracer
;
1469 int cpu_file
= iter
->cpu_file
;
1474 /* copy the tracer to avoid using a global lock all around */
1475 mutex_lock(&trace_types_lock
);
1476 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
1477 old_tracer
= current_trace
;
1478 *iter
->trace
= *current_trace
;
1480 mutex_unlock(&trace_types_lock
);
1482 atomic_inc(&trace_record_cmdline_disabled
);
1484 if (*pos
!= iter
->pos
) {
1489 ftrace_disable_cpu();
1491 if (cpu_file
== TRACE_PIPE_ALL_CPU
) {
1492 for_each_tracing_cpu(cpu
)
1493 ring_buffer_iter_reset(iter
->buffer_iter
[cpu
]);
1495 ring_buffer_iter_reset(iter
->buffer_iter
[cpu_file
]);
1498 ftrace_enable_cpu();
1500 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
1505 p
= s_next(m
, p
, &l
);
1511 static void s_stop(struct seq_file
*m
, void *p
)
1513 atomic_dec(&trace_record_cmdline_disabled
);
1516 static void print_lat_help_header(struct seq_file
*m
)
1518 seq_puts(m
, "# _------=> CPU# \n");
1519 seq_puts(m
, "# / _-----=> irqs-off \n");
1520 seq_puts(m
, "# | / _----=> need-resched \n");
1521 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
1522 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
1523 seq_puts(m
, "# |||| / \n");
1524 seq_puts(m
, "# ||||| delay \n");
1525 seq_puts(m
, "# cmd pid ||||| time | caller \n");
1526 seq_puts(m
, "# \\ / ||||| \\ | / \n");
1529 static void print_func_help_header(struct seq_file
*m
)
1531 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1532 seq_puts(m
, "# | | | | |\n");
1537 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
1539 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1540 struct trace_array
*tr
= iter
->tr
;
1541 struct trace_array_cpu
*data
= tr
->data
[tr
->cpu
];
1542 struct tracer
*type
= current_trace
;
1543 unsigned long total
;
1544 unsigned long entries
;
1545 const char *name
= "preemption";
1550 entries
= ring_buffer_entries(iter
->tr
->buffer
);
1552 ring_buffer_overruns(iter
->tr
->buffer
);
1554 seq_printf(m
, "# %s latency trace v1.1.5 on %s\n",
1556 seq_puts(m
, "# -----------------------------------"
1557 "---------------------------------\n");
1558 seq_printf(m
, "# latency: %lu us, #%lu/%lu, CPU#%d |"
1559 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1560 nsecs_to_usecs(data
->saved_latency
),
1564 #if defined(CONFIG_PREEMPT_NONE)
1566 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1568 #elif defined(CONFIG_PREEMPT)
1573 /* These are reserved for later use */
1576 seq_printf(m
, " #P:%d)\n", num_online_cpus());
1580 seq_puts(m
, "# -----------------\n");
1581 seq_printf(m
, "# | task: %.16s-%d "
1582 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1583 data
->comm
, data
->pid
, data
->uid
, data
->nice
,
1584 data
->policy
, data
->rt_priority
);
1585 seq_puts(m
, "# -----------------\n");
1587 if (data
->critical_start
) {
1588 seq_puts(m
, "# => started at: ");
1589 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
1590 trace_print_seq(m
, &iter
->seq
);
1591 seq_puts(m
, "\n# => ended at: ");
1592 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
1593 trace_print_seq(m
, &iter
->seq
);
1600 static void test_cpu_buff_start(struct trace_iterator
*iter
)
1602 struct trace_seq
*s
= &iter
->seq
;
1604 if (!(trace_flags
& TRACE_ITER_ANNOTATE
))
1607 if (!(iter
->iter_flags
& TRACE_FILE_ANNOTATE
))
1610 if (cpumask_test_cpu(iter
->cpu
, iter
->started
))
1613 cpumask_set_cpu(iter
->cpu
, iter
->started
);
1614 trace_seq_printf(s
, "##### CPU %u buffer started ####\n", iter
->cpu
);
1617 static enum print_line_t
print_trace_fmt(struct trace_iterator
*iter
)
1619 struct trace_seq
*s
= &iter
->seq
;
1620 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1621 struct trace_entry
*entry
;
1622 struct trace_event
*event
;
1626 test_cpu_buff_start(iter
);
1628 event
= ftrace_find_event(entry
->type
);
1630 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1631 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
1632 if (!trace_print_lat_context(iter
))
1635 if (!trace_print_context(iter
))
1641 return event
->trace(iter
, sym_flags
);
1643 if (!trace_seq_printf(s
, "Unknown type %d\n", entry
->type
))
1646 return TRACE_TYPE_HANDLED
;
1648 return TRACE_TYPE_PARTIAL_LINE
;
1651 static enum print_line_t
print_raw_fmt(struct trace_iterator
*iter
)
1653 struct trace_seq
*s
= &iter
->seq
;
1654 struct trace_entry
*entry
;
1655 struct trace_event
*event
;
1659 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1660 if (!trace_seq_printf(s
, "%d %d %llu ",
1661 entry
->pid
, iter
->cpu
, iter
->ts
))
1665 event
= ftrace_find_event(entry
->type
);
1667 return event
->raw(iter
, 0);
1669 if (!trace_seq_printf(s
, "%d ?\n", entry
->type
))
1672 return TRACE_TYPE_HANDLED
;
1674 return TRACE_TYPE_PARTIAL_LINE
;
1677 static enum print_line_t
print_hex_fmt(struct trace_iterator
*iter
)
1679 struct trace_seq
*s
= &iter
->seq
;
1680 unsigned char newline
= '\n';
1681 struct trace_entry
*entry
;
1682 struct trace_event
*event
;
1686 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1687 SEQ_PUT_HEX_FIELD_RET(s
, entry
->pid
);
1688 SEQ_PUT_HEX_FIELD_RET(s
, iter
->cpu
);
1689 SEQ_PUT_HEX_FIELD_RET(s
, iter
->ts
);
1692 event
= ftrace_find_event(entry
->type
);
1694 enum print_line_t ret
= event
->hex(iter
, 0);
1695 if (ret
!= TRACE_TYPE_HANDLED
)
1699 SEQ_PUT_FIELD_RET(s
, newline
);
1701 return TRACE_TYPE_HANDLED
;
1704 static enum print_line_t
print_bprintk_msg_only(struct trace_iterator
*iter
)
1706 struct trace_seq
*s
= &iter
->seq
;
1707 struct trace_entry
*entry
= iter
->ent
;
1708 struct bprint_entry
*field
;
1711 trace_assign_type(field
, entry
);
1713 ret
= trace_seq_bprintf(s
, field
->fmt
, field
->buf
);
1715 return TRACE_TYPE_PARTIAL_LINE
;
1717 return TRACE_TYPE_HANDLED
;
1720 static enum print_line_t
print_printk_msg_only(struct trace_iterator
*iter
)
1722 struct trace_seq
*s
= &iter
->seq
;
1723 struct trace_entry
*entry
= iter
->ent
;
1724 struct print_entry
*field
;
1727 trace_assign_type(field
, entry
);
1729 ret
= trace_seq_printf(s
, "%s", field
->buf
);
1731 return TRACE_TYPE_PARTIAL_LINE
;
1733 return TRACE_TYPE_HANDLED
;
1736 static enum print_line_t
print_bin_fmt(struct trace_iterator
*iter
)
1738 struct trace_seq
*s
= &iter
->seq
;
1739 struct trace_entry
*entry
;
1740 struct trace_event
*event
;
1744 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1745 SEQ_PUT_FIELD_RET(s
, entry
->pid
);
1746 SEQ_PUT_FIELD_RET(s
, iter
->cpu
);
1747 SEQ_PUT_FIELD_RET(s
, iter
->ts
);
1750 event
= ftrace_find_event(entry
->type
);
1751 return event
? event
->binary(iter
, 0) : TRACE_TYPE_HANDLED
;
1754 static int trace_empty(struct trace_iterator
*iter
)
1758 /* If we are looking at one CPU buffer, only check that one */
1759 if (iter
->cpu_file
!= TRACE_PIPE_ALL_CPU
) {
1760 cpu
= iter
->cpu_file
;
1761 if (iter
->buffer_iter
[cpu
]) {
1762 if (!ring_buffer_iter_empty(iter
->buffer_iter
[cpu
]))
1765 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
1771 for_each_tracing_cpu(cpu
) {
1772 if (iter
->buffer_iter
[cpu
]) {
1773 if (!ring_buffer_iter_empty(iter
->buffer_iter
[cpu
]))
1776 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
1784 static enum print_line_t
print_trace_line(struct trace_iterator
*iter
)
1786 enum print_line_t ret
;
1788 if (iter
->trace
&& iter
->trace
->print_line
) {
1789 ret
= iter
->trace
->print_line(iter
);
1790 if (ret
!= TRACE_TYPE_UNHANDLED
)
1794 if (iter
->ent
->type
== TRACE_BPRINT
&&
1795 trace_flags
& TRACE_ITER_PRINTK
&&
1796 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
1797 return print_bprintk_msg_only(iter
);
1799 if (iter
->ent
->type
== TRACE_PRINT
&&
1800 trace_flags
& TRACE_ITER_PRINTK
&&
1801 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
1802 return print_printk_msg_only(iter
);
1804 if (trace_flags
& TRACE_ITER_BIN
)
1805 return print_bin_fmt(iter
);
1807 if (trace_flags
& TRACE_ITER_HEX
)
1808 return print_hex_fmt(iter
);
1810 if (trace_flags
& TRACE_ITER_RAW
)
1811 return print_raw_fmt(iter
);
1813 return print_trace_fmt(iter
);
1816 static int s_show(struct seq_file
*m
, void *v
)
1818 struct trace_iterator
*iter
= v
;
1820 if (iter
->ent
== NULL
) {
1822 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
1825 if (iter
->trace
&& iter
->trace
->print_header
)
1826 iter
->trace
->print_header(m
);
1827 else if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
1828 /* print nothing if the buffers are empty */
1829 if (trace_empty(iter
))
1831 print_trace_header(m
, iter
);
1832 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1833 print_lat_help_header(m
);
1835 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1836 print_func_help_header(m
);
1839 print_trace_line(iter
);
1840 trace_print_seq(m
, &iter
->seq
);
1846 static struct seq_operations tracer_seq_ops
= {
1853 static struct trace_iterator
*
1854 __tracing_open(struct inode
*inode
, struct file
*file
)
1856 long cpu_file
= (long) inode
->i_private
;
1857 void *fail_ret
= ERR_PTR(-ENOMEM
);
1858 struct trace_iterator
*iter
;
1862 if (tracing_disabled
)
1863 return ERR_PTR(-ENODEV
);
1865 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
1867 return ERR_PTR(-ENOMEM
);
1870 * We make a copy of the current tracer to avoid concurrent
1871 * changes on it while we are reading.
1873 mutex_lock(&trace_types_lock
);
1874 iter
->trace
= kzalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
1879 *iter
->trace
= *current_trace
;
1881 if (current_trace
&& current_trace
->print_max
)
1884 iter
->tr
= &global_trace
;
1886 mutex_init(&iter
->mutex
);
1887 iter
->cpu_file
= cpu_file
;
1889 /* Notify the tracer early; before we stop tracing. */
1890 if (iter
->trace
&& iter
->trace
->open
)
1891 iter
->trace
->open(iter
);
1893 /* Annotate start of buffers if we had overruns */
1894 if (ring_buffer_overruns(iter
->tr
->buffer
))
1895 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
1897 if (iter
->cpu_file
== TRACE_PIPE_ALL_CPU
) {
1898 for_each_tracing_cpu(cpu
) {
1900 iter
->buffer_iter
[cpu
] =
1901 ring_buffer_read_start(iter
->tr
->buffer
, cpu
);
1904 cpu
= iter
->cpu_file
;
1905 iter
->buffer_iter
[cpu
] =
1906 ring_buffer_read_start(iter
->tr
->buffer
, cpu
);
1909 /* TODO stop tracer */
1910 ret
= seq_open(file
, &tracer_seq_ops
);
1912 fail_ret
= ERR_PTR(ret
);
1916 m
= file
->private_data
;
1919 /* stop the trace while dumping */
1922 mutex_unlock(&trace_types_lock
);
1927 for_each_tracing_cpu(cpu
) {
1928 if (iter
->buffer_iter
[cpu
])
1929 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
1932 mutex_unlock(&trace_types_lock
);
1939 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
1941 if (tracing_disabled
)
1944 filp
->private_data
= inode
->i_private
;
1948 static int tracing_release(struct inode
*inode
, struct file
*file
)
1950 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
1951 struct trace_iterator
*iter
= m
->private;
1954 mutex_lock(&trace_types_lock
);
1955 for_each_tracing_cpu(cpu
) {
1956 if (iter
->buffer_iter
[cpu
])
1957 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
1960 if (iter
->trace
&& iter
->trace
->close
)
1961 iter
->trace
->close(iter
);
1963 /* reenable tracing if it was previously enabled */
1965 mutex_unlock(&trace_types_lock
);
1967 seq_release(inode
, file
);
1968 mutex_destroy(&iter
->mutex
);
1974 static int tracing_open(struct inode
*inode
, struct file
*file
)
1976 struct trace_iterator
*iter
;
1979 iter
= __tracing_open(inode
, file
);
1981 ret
= PTR_ERR(iter
);
1982 else if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
1983 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
1989 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1991 struct tracer
*t
= m
->private;
2003 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
2005 struct tracer
*t
= m
->private;
2008 mutex_lock(&trace_types_lock
);
2009 for (; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
2015 static void t_stop(struct seq_file
*m
, void *p
)
2017 mutex_unlock(&trace_types_lock
);
2020 static int t_show(struct seq_file
*m
, void *v
)
2022 struct tracer
*t
= v
;
2027 seq_printf(m
, "%s", t
->name
);
2036 static struct seq_operations show_traces_seq_ops
= {
2043 static int show_traces_open(struct inode
*inode
, struct file
*file
)
2047 if (tracing_disabled
)
2050 ret
= seq_open(file
, &show_traces_seq_ops
);
2052 struct seq_file
*m
= file
->private_data
;
2053 m
->private = trace_types
;
2059 static const struct file_operations tracing_fops
= {
2060 .open
= tracing_open
,
2062 .llseek
= seq_lseek
,
2063 .release
= tracing_release
,
2066 static const struct file_operations show_traces_fops
= {
2067 .open
= show_traces_open
,
2069 .release
= seq_release
,
2073 * Only trace on a CPU if the bitmask is set:
2075 static cpumask_var_t tracing_cpumask
;
2078 * The tracer itself will not take this lock, but still we want
2079 * to provide a consistent cpumask to user-space:
2081 static DEFINE_MUTEX(tracing_cpumask_update_lock
);
2084 * Temporary storage for the character representation of the
2085 * CPU bitmask (and one more byte for the newline):
2087 static char mask_str
[NR_CPUS
+ 1];
2090 tracing_cpumask_read(struct file
*filp
, char __user
*ubuf
,
2091 size_t count
, loff_t
*ppos
)
2095 mutex_lock(&tracing_cpumask_update_lock
);
2097 len
= cpumask_scnprintf(mask_str
, count
, tracing_cpumask
);
2098 if (count
- len
< 2) {
2102 len
+= sprintf(mask_str
+ len
, "\n");
2103 count
= simple_read_from_buffer(ubuf
, count
, ppos
, mask_str
, NR_CPUS
+1);
2106 mutex_unlock(&tracing_cpumask_update_lock
);
2112 tracing_cpumask_write(struct file
*filp
, const char __user
*ubuf
,
2113 size_t count
, loff_t
*ppos
)
2116 cpumask_var_t tracing_cpumask_new
;
2118 if (!alloc_cpumask_var(&tracing_cpumask_new
, GFP_KERNEL
))
2121 mutex_lock(&tracing_cpumask_update_lock
);
2122 err
= cpumask_parse_user(ubuf
, count
, tracing_cpumask_new
);
2126 local_irq_disable();
2127 __raw_spin_lock(&ftrace_max_lock
);
2128 for_each_tracing_cpu(cpu
) {
2130 * Increase/decrease the disabled counter if we are
2131 * about to flip a bit in the cpumask:
2133 if (cpumask_test_cpu(cpu
, tracing_cpumask
) &&
2134 !cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
2135 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
2137 if (!cpumask_test_cpu(cpu
, tracing_cpumask
) &&
2138 cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
2139 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
2142 __raw_spin_unlock(&ftrace_max_lock
);
2145 cpumask_copy(tracing_cpumask
, tracing_cpumask_new
);
2147 mutex_unlock(&tracing_cpumask_update_lock
);
2148 free_cpumask_var(tracing_cpumask_new
);
2153 mutex_unlock(&tracing_cpumask_update_lock
);
2154 free_cpumask_var(tracing_cpumask
);
2159 static const struct file_operations tracing_cpumask_fops
= {
2160 .open
= tracing_open_generic
,
2161 .read
= tracing_cpumask_read
,
2162 .write
= tracing_cpumask_write
,
2166 tracing_trace_options_read(struct file
*filp
, char __user
*ubuf
,
2167 size_t cnt
, loff_t
*ppos
)
2169 struct tracer_opt
*trace_opts
;
2177 /* calculate max size */
2178 for (i
= 0; trace_options
[i
]; i
++) {
2179 len
+= strlen(trace_options
[i
]);
2180 len
+= 3; /* "no" and newline */
2183 mutex_lock(&trace_types_lock
);
2184 tracer_flags
= current_trace
->flags
->val
;
2185 trace_opts
= current_trace
->flags
->opts
;
2188 * Increase the size with names of options specific
2189 * of the current tracer.
2191 for (i
= 0; trace_opts
[i
].name
; i
++) {
2192 len
+= strlen(trace_opts
[i
].name
);
2193 len
+= 3; /* "no" and newline */
2196 /* +2 for \n and \0 */
2197 buf
= kmalloc(len
+ 2, GFP_KERNEL
);
2199 mutex_unlock(&trace_types_lock
);
2203 for (i
= 0; trace_options
[i
]; i
++) {
2204 if (trace_flags
& (1 << i
))
2205 r
+= sprintf(buf
+ r
, "%s\n", trace_options
[i
]);
2207 r
+= sprintf(buf
+ r
, "no%s\n", trace_options
[i
]);
2210 for (i
= 0; trace_opts
[i
].name
; i
++) {
2211 if (tracer_flags
& trace_opts
[i
].bit
)
2212 r
+= sprintf(buf
+ r
, "%s\n",
2213 trace_opts
[i
].name
);
2215 r
+= sprintf(buf
+ r
, "no%s\n",
2216 trace_opts
[i
].name
);
2218 mutex_unlock(&trace_types_lock
);
2220 WARN_ON(r
>= len
+ 2);
2222 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2228 /* Try to assign a tracer specific option */
2229 static int set_tracer_option(struct tracer
*trace
, char *cmp
, int neg
)
2231 struct tracer_flags
*trace_flags
= trace
->flags
;
2232 struct tracer_opt
*opts
= NULL
;
2236 for (i
= 0; trace_flags
->opts
[i
].name
; i
++) {
2237 opts
= &trace_flags
->opts
[i
];
2238 len
= strlen(opts
->name
);
2240 if (strncmp(cmp
, opts
->name
, len
) == 0) {
2241 ret
= trace
->set_flag(trace_flags
->val
,
2247 if (!trace_flags
->opts
[i
].name
)
2250 /* Refused to handle */
2255 trace_flags
->val
&= ~opts
->bit
;
2257 trace_flags
->val
|= opts
->bit
;
2262 static void set_tracer_flags(unsigned int mask
, int enabled
)
2264 /* do nothing if flag is already set */
2265 if (!!(trace_flags
& mask
) == !!enabled
)
2269 trace_flags
|= mask
;
2271 trace_flags
&= ~mask
;
2273 if (mask
== TRACE_ITER_GLOBAL_CLK
) {
2277 func
= trace_clock_global
;
2279 func
= trace_clock_local
;
2281 mutex_lock(&trace_types_lock
);
2282 ring_buffer_set_clock(global_trace
.buffer
, func
);
2285 ring_buffer_set_clock(max_tr
.buffer
, func
);
2286 mutex_unlock(&trace_types_lock
);
2291 tracing_trace_options_write(struct file
*filp
, const char __user
*ubuf
,
2292 size_t cnt
, loff_t
*ppos
)
2300 if (cnt
>= sizeof(buf
))
2303 if (copy_from_user(&buf
, ubuf
, cnt
))
2308 if (strncmp(buf
, "no", 2) == 0) {
2313 for (i
= 0; trace_options
[i
]; i
++) {
2314 int len
= strlen(trace_options
[i
]);
2316 if (strncmp(cmp
, trace_options
[i
], len
) == 0) {
2317 set_tracer_flags(1 << i
, !neg
);
2322 /* If no option could be set, test the specific tracer options */
2323 if (!trace_options
[i
]) {
2324 mutex_lock(&trace_types_lock
);
2325 ret
= set_tracer_option(current_trace
, cmp
, neg
);
2326 mutex_unlock(&trace_types_lock
);
2336 static const struct file_operations tracing_iter_fops
= {
2337 .open
= tracing_open_generic
,
2338 .read
= tracing_trace_options_read
,
2339 .write
= tracing_trace_options_write
,
2342 static const char readme_msg
[] =
2343 "tracing mini-HOWTO:\n\n"
2345 "# mount -t debugfs nodev /debug\n\n"
2346 "# cat /debug/tracing/available_tracers\n"
2347 "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
2348 "# cat /debug/tracing/current_tracer\n"
2350 "# echo sched_switch > /debug/tracing/current_tracer\n"
2351 "# cat /debug/tracing/current_tracer\n"
2353 "# cat /debug/tracing/trace_options\n"
2354 "noprint-parent nosym-offset nosym-addr noverbose\n"
2355 "# echo print-parent > /debug/tracing/trace_options\n"
2356 "# echo 1 > /debug/tracing/tracing_enabled\n"
2357 "# cat /debug/tracing/trace > /tmp/trace.txt\n"
2358 "echo 0 > /debug/tracing/tracing_enabled\n"
2362 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
2363 size_t cnt
, loff_t
*ppos
)
2365 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
2366 readme_msg
, strlen(readme_msg
));
2369 static const struct file_operations tracing_readme_fops
= {
2370 .open
= tracing_open_generic
,
2371 .read
= tracing_readme_read
,
2375 tracing_ctrl_read(struct file
*filp
, char __user
*ubuf
,
2376 size_t cnt
, loff_t
*ppos
)
2381 r
= sprintf(buf
, "%u\n", tracer_enabled
);
2382 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2386 tracing_ctrl_write(struct file
*filp
, const char __user
*ubuf
,
2387 size_t cnt
, loff_t
*ppos
)
2389 struct trace_array
*tr
= filp
->private_data
;
2394 if (cnt
>= sizeof(buf
))
2397 if (copy_from_user(&buf
, ubuf
, cnt
))
2402 ret
= strict_strtoul(buf
, 10, &val
);
2408 mutex_lock(&trace_types_lock
);
2409 if (tracer_enabled
^ val
) {
2412 if (current_trace
->start
)
2413 current_trace
->start(tr
);
2418 if (current_trace
->stop
)
2419 current_trace
->stop(tr
);
2422 mutex_unlock(&trace_types_lock
);
2430 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
2431 size_t cnt
, loff_t
*ppos
)
2433 char buf
[max_tracer_type_len
+2];
2436 mutex_lock(&trace_types_lock
);
2438 r
= sprintf(buf
, "%s\n", current_trace
->name
);
2440 r
= sprintf(buf
, "\n");
2441 mutex_unlock(&trace_types_lock
);
2443 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2446 int tracer_init(struct tracer
*t
, struct trace_array
*tr
)
2448 tracing_reset_online_cpus(tr
);
2452 static int tracing_resize_ring_buffer(unsigned long size
)
2457 * If kernel or user changes the size of the ring buffer
2458 * we use the size that was given, and we can forget about
2459 * expanding it later.
2461 ring_buffer_expanded
= 1;
2463 ret
= ring_buffer_resize(global_trace
.buffer
, size
);
2467 ret
= ring_buffer_resize(max_tr
.buffer
, size
);
2471 r
= ring_buffer_resize(global_trace
.buffer
,
2472 global_trace
.entries
);
2475 * AARGH! We are left with different
2476 * size max buffer!!!!
2477 * The max buffer is our "snapshot" buffer.
2478 * When a tracer needs a snapshot (one of the
2479 * latency tracers), it swaps the max buffer
2480 * with the saved snap shot. We succeeded to
2481 * update the size of the main buffer, but failed to
2482 * update the size of the max buffer. But when we tried
2483 * to reset the main buffer to the original size, we
2484 * failed there too. This is very unlikely to
2485 * happen, but if it does, warn and kill all
2489 tracing_disabled
= 1;
2494 global_trace
.entries
= size
;
2500 * tracing_update_buffers - used by tracing facility to expand ring buffers
2502 * To save on memory when the tracing is never used on a system with it
2503 * configured in. The ring buffers are set to a minimum size. But once
2504 * a user starts to use the tracing facility, then they need to grow
2505 * to their default size.
2507 * This function is to be called when a tracer is about to be used.
2509 int tracing_update_buffers(void)
2513 mutex_lock(&trace_types_lock
);
2514 if (!ring_buffer_expanded
)
2515 ret
= tracing_resize_ring_buffer(trace_buf_size
);
2516 mutex_unlock(&trace_types_lock
);
2521 struct trace_option_dentry
;
2523 static struct trace_option_dentry
*
2524 create_trace_option_files(struct tracer
*tracer
);
2527 destroy_trace_option_files(struct trace_option_dentry
*topts
);
2529 static int tracing_set_tracer(const char *buf
)
2531 static struct trace_option_dentry
*topts
;
2532 struct trace_array
*tr
= &global_trace
;
2536 mutex_lock(&trace_types_lock
);
2538 if (!ring_buffer_expanded
) {
2539 ret
= tracing_resize_ring_buffer(trace_buf_size
);
2545 for (t
= trace_types
; t
; t
= t
->next
) {
2546 if (strcmp(t
->name
, buf
) == 0)
2553 if (t
== current_trace
)
2556 trace_branch_disable();
2557 if (current_trace
&& current_trace
->reset
)
2558 current_trace
->reset(tr
);
2560 destroy_trace_option_files(topts
);
2564 topts
= create_trace_option_files(current_trace
);
2567 ret
= tracer_init(t
, tr
);
2572 trace_branch_enable(tr
);
2574 mutex_unlock(&trace_types_lock
);
2580 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
2581 size_t cnt
, loff_t
*ppos
)
2583 char buf
[max_tracer_type_len
+1];
2590 if (cnt
> max_tracer_type_len
)
2591 cnt
= max_tracer_type_len
;
2593 if (copy_from_user(&buf
, ubuf
, cnt
))
2598 /* strip ending whitespace. */
2599 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
2602 err
= tracing_set_tracer(buf
);
2612 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
2613 size_t cnt
, loff_t
*ppos
)
2615 unsigned long *ptr
= filp
->private_data
;
2619 r
= snprintf(buf
, sizeof(buf
), "%ld\n",
2620 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
2621 if (r
> sizeof(buf
))
2623 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2627 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
2628 size_t cnt
, loff_t
*ppos
)
2630 unsigned long *ptr
= filp
->private_data
;
2635 if (cnt
>= sizeof(buf
))
2638 if (copy_from_user(&buf
, ubuf
, cnt
))
2643 ret
= strict_strtoul(buf
, 10, &val
);
2652 static int tracing_open_pipe(struct inode
*inode
, struct file
*filp
)
2654 long cpu_file
= (long) inode
->i_private
;
2655 struct trace_iterator
*iter
;
2658 if (tracing_disabled
)
2661 mutex_lock(&trace_types_lock
);
2663 /* We only allow one reader per cpu */
2664 if (cpu_file
== TRACE_PIPE_ALL_CPU
) {
2665 if (!cpumask_empty(tracing_reader_cpumask
)) {
2669 cpumask_setall(tracing_reader_cpumask
);
2671 if (!cpumask_test_cpu(cpu_file
, tracing_reader_cpumask
))
2672 cpumask_set_cpu(cpu_file
, tracing_reader_cpumask
);
2679 /* create a buffer to store the information to pass to userspace */
2680 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2687 * We make a copy of the current tracer to avoid concurrent
2688 * changes on it while we are reading.
2690 iter
->trace
= kmalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
2696 *iter
->trace
= *current_trace
;
2698 if (!alloc_cpumask_var(&iter
->started
, GFP_KERNEL
)) {
2703 /* trace pipe does not show start of buffer */
2704 cpumask_setall(iter
->started
);
2706 iter
->cpu_file
= cpu_file
;
2707 iter
->tr
= &global_trace
;
2708 mutex_init(&iter
->mutex
);
2709 filp
->private_data
= iter
;
2711 if (iter
->trace
->pipe_open
)
2712 iter
->trace
->pipe_open(iter
);
2715 mutex_unlock(&trace_types_lock
);
2721 mutex_unlock(&trace_types_lock
);
2725 static int tracing_release_pipe(struct inode
*inode
, struct file
*file
)
2727 struct trace_iterator
*iter
= file
->private_data
;
2729 mutex_lock(&trace_types_lock
);
2731 if (iter
->cpu_file
== TRACE_PIPE_ALL_CPU
)
2732 cpumask_clear(tracing_reader_cpumask
);
2734 cpumask_clear_cpu(iter
->cpu_file
, tracing_reader_cpumask
);
2736 mutex_unlock(&trace_types_lock
);
2738 free_cpumask_var(iter
->started
);
2739 mutex_destroy(&iter
->mutex
);
2747 tracing_poll_pipe(struct file
*filp
, poll_table
*poll_table
)
2749 struct trace_iterator
*iter
= filp
->private_data
;
2751 if (trace_flags
& TRACE_ITER_BLOCK
) {
2753 * Always select as readable when in blocking mode
2755 return POLLIN
| POLLRDNORM
;
2757 if (!trace_empty(iter
))
2758 return POLLIN
| POLLRDNORM
;
2759 poll_wait(filp
, &trace_wait
, poll_table
);
2760 if (!trace_empty(iter
))
2761 return POLLIN
| POLLRDNORM
;
2768 void default_wait_pipe(struct trace_iterator
*iter
)
2772 prepare_to_wait(&trace_wait
, &wait
, TASK_INTERRUPTIBLE
);
2774 if (trace_empty(iter
))
2777 finish_wait(&trace_wait
, &wait
);
2781 * This is a make-shift waitqueue.
2782 * A tracer might use this callback on some rare cases:
2784 * 1) the current tracer might hold the runqueue lock when it wakes up
2785 * a reader, hence a deadlock (sched, function, and function graph tracers)
2786 * 2) the function tracers, trace all functions, we don't want
2787 * the overhead of calling wake_up and friends
2788 * (and tracing them too)
2790 * Anyway, this is really very primitive wakeup.
2792 void poll_wait_pipe(struct trace_iterator
*iter
)
2794 set_current_state(TASK_INTERRUPTIBLE
);
2795 /* sleep for 100 msecs, and try again. */
2796 schedule_timeout(HZ
/ 10);
2799 /* Must be called with trace_types_lock mutex held. */
2800 static int tracing_wait_pipe(struct file
*filp
)
2802 struct trace_iterator
*iter
= filp
->private_data
;
2804 while (trace_empty(iter
)) {
2806 if ((filp
->f_flags
& O_NONBLOCK
)) {
2810 mutex_unlock(&iter
->mutex
);
2812 iter
->trace
->wait_pipe(iter
);
2814 mutex_lock(&iter
->mutex
);
2816 if (signal_pending(current
))
2820 * We block until we read something and tracing is disabled.
2821 * We still block if tracing is disabled, but we have never
2822 * read anything. This allows a user to cat this file, and
2823 * then enable tracing. But after we have read something,
2824 * we give an EOF when tracing is again disabled.
2826 * iter->pos will be 0 if we haven't read anything.
2828 if (!tracer_enabled
&& iter
->pos
)
2839 tracing_read_pipe(struct file
*filp
, char __user
*ubuf
,
2840 size_t cnt
, loff_t
*ppos
)
2842 struct trace_iterator
*iter
= filp
->private_data
;
2843 static struct tracer
*old_tracer
;
2846 /* return any leftover data */
2847 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
2851 trace_seq_init(&iter
->seq
);
2853 /* copy the tracer to avoid using a global lock all around */
2854 mutex_lock(&trace_types_lock
);
2855 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
2856 old_tracer
= current_trace
;
2857 *iter
->trace
= *current_trace
;
2859 mutex_unlock(&trace_types_lock
);
2862 * Avoid more than one consumer on a single file descriptor
2863 * This is just a matter of traces coherency, the ring buffer itself
2866 mutex_lock(&iter
->mutex
);
2867 if (iter
->trace
->read
) {
2868 sret
= iter
->trace
->read(iter
, filp
, ubuf
, cnt
, ppos
);
2874 sret
= tracing_wait_pipe(filp
);
2878 /* stop when tracing is finished */
2879 if (trace_empty(iter
)) {
2884 if (cnt
>= PAGE_SIZE
)
2885 cnt
= PAGE_SIZE
- 1;
2887 /* reset all but tr, trace, and overruns */
2888 memset(&iter
->seq
, 0,
2889 sizeof(struct trace_iterator
) -
2890 offsetof(struct trace_iterator
, seq
));
2893 while (find_next_entry_inc(iter
) != NULL
) {
2894 enum print_line_t ret
;
2895 int len
= iter
->seq
.len
;
2897 ret
= print_trace_line(iter
);
2898 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
2899 /* don't print partial lines */
2900 iter
->seq
.len
= len
;
2903 if (ret
!= TRACE_TYPE_NO_CONSUME
)
2904 trace_consume(iter
);
2906 if (iter
->seq
.len
>= cnt
)
2910 /* Now copy what we have to the user */
2911 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
2912 if (iter
->seq
.readpos
>= iter
->seq
.len
)
2913 trace_seq_init(&iter
->seq
);
2916 * If there was nothing to send to user, inspite of consuming trace
2917 * entries, go back to wait for more entries.
2923 mutex_unlock(&iter
->mutex
);
2928 static void tracing_pipe_buf_release(struct pipe_inode_info
*pipe
,
2929 struct pipe_buffer
*buf
)
2931 __free_page(buf
->page
);
2934 static void tracing_spd_release_pipe(struct splice_pipe_desc
*spd
,
2937 __free_page(spd
->pages
[idx
]);
2940 static struct pipe_buf_operations tracing_pipe_buf_ops
= {
2942 .map
= generic_pipe_buf_map
,
2943 .unmap
= generic_pipe_buf_unmap
,
2944 .confirm
= generic_pipe_buf_confirm
,
2945 .release
= tracing_pipe_buf_release
,
2946 .steal
= generic_pipe_buf_steal
,
2947 .get
= generic_pipe_buf_get
,
2951 tracing_fill_pipe_page(size_t rem
, struct trace_iterator
*iter
)
2956 /* Seq buffer is page-sized, exactly what we need. */
2958 count
= iter
->seq
.len
;
2959 ret
= print_trace_line(iter
);
2960 count
= iter
->seq
.len
- count
;
2963 iter
->seq
.len
-= count
;
2966 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
2967 iter
->seq
.len
-= count
;
2971 trace_consume(iter
);
2973 if (!find_next_entry_inc(iter
)) {
2983 static ssize_t
tracing_splice_read_pipe(struct file
*filp
,
2985 struct pipe_inode_info
*pipe
,
2989 struct page
*pages
[PIPE_BUFFERS
];
2990 struct partial_page partial
[PIPE_BUFFERS
];
2991 struct trace_iterator
*iter
= filp
->private_data
;
2992 struct splice_pipe_desc spd
= {
2995 .nr_pages
= 0, /* This gets updated below. */
2997 .ops
= &tracing_pipe_buf_ops
,
2998 .spd_release
= tracing_spd_release_pipe
,
3000 static struct tracer
*old_tracer
;
3005 /* copy the tracer to avoid using a global lock all around */
3006 mutex_lock(&trace_types_lock
);
3007 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
3008 old_tracer
= current_trace
;
3009 *iter
->trace
= *current_trace
;
3011 mutex_unlock(&trace_types_lock
);
3013 mutex_lock(&iter
->mutex
);
3015 if (iter
->trace
->splice_read
) {
3016 ret
= iter
->trace
->splice_read(iter
, filp
,
3017 ppos
, pipe
, len
, flags
);
3022 ret
= tracing_wait_pipe(filp
);
3026 if (!iter
->ent
&& !find_next_entry_inc(iter
)) {
3031 /* Fill as many pages as possible. */
3032 for (i
= 0, rem
= len
; i
< PIPE_BUFFERS
&& rem
; i
++) {
3033 pages
[i
] = alloc_page(GFP_KERNEL
);
3037 rem
= tracing_fill_pipe_page(rem
, iter
);
3039 /* Copy the data into the page, so we can start over. */
3040 ret
= trace_seq_to_buffer(&iter
->seq
,
3041 page_address(pages
[i
]),
3044 __free_page(pages
[i
]);
3047 partial
[i
].offset
= 0;
3048 partial
[i
].len
= iter
->seq
.len
;
3050 trace_seq_init(&iter
->seq
);
3053 mutex_unlock(&iter
->mutex
);
3057 return splice_to_pipe(pipe
, &spd
);
3060 mutex_unlock(&iter
->mutex
);
3066 tracing_entries_read(struct file
*filp
, char __user
*ubuf
,
3067 size_t cnt
, loff_t
*ppos
)
3069 struct trace_array
*tr
= filp
->private_data
;
3073 mutex_lock(&trace_types_lock
);
3074 if (!ring_buffer_expanded
)
3075 r
= sprintf(buf
, "%lu (expanded: %lu)\n",
3077 trace_buf_size
>> 10);
3079 r
= sprintf(buf
, "%lu\n", tr
->entries
>> 10);
3080 mutex_unlock(&trace_types_lock
);
3082 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3086 tracing_entries_write(struct file
*filp
, const char __user
*ubuf
,
3087 size_t cnt
, loff_t
*ppos
)
3093 if (cnt
>= sizeof(buf
))
3096 if (copy_from_user(&buf
, ubuf
, cnt
))
3101 ret
= strict_strtoul(buf
, 10, &val
);
3105 /* must have at least 1 entry */
3109 mutex_lock(&trace_types_lock
);
3113 /* disable all cpu buffers */
3114 for_each_tracing_cpu(cpu
) {
3115 if (global_trace
.data
[cpu
])
3116 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
3117 if (max_tr
.data
[cpu
])
3118 atomic_inc(&max_tr
.data
[cpu
]->disabled
);
3121 /* value is in KB */
3124 if (val
!= global_trace
.entries
) {
3125 ret
= tracing_resize_ring_buffer(val
);
3134 /* If check pages failed, return ENOMEM */
3135 if (tracing_disabled
)
3138 for_each_tracing_cpu(cpu
) {
3139 if (global_trace
.data
[cpu
])
3140 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
3141 if (max_tr
.data
[cpu
])
3142 atomic_dec(&max_tr
.data
[cpu
]->disabled
);
3146 max_tr
.entries
= global_trace
.entries
;
3147 mutex_unlock(&trace_types_lock
);
3152 static int mark_printk(const char *fmt
, ...)
3156 va_start(args
, fmt
);
3157 ret
= trace_vprintk(0, -1, fmt
, args
);
3163 tracing_mark_write(struct file
*filp
, const char __user
*ubuf
,
3164 size_t cnt
, loff_t
*fpos
)
3169 if (tracing_disabled
)
3172 if (cnt
> TRACE_BUF_SIZE
)
3173 cnt
= TRACE_BUF_SIZE
;
3175 buf
= kmalloc(cnt
+ 1, GFP_KERNEL
);
3179 if (copy_from_user(buf
, ubuf
, cnt
)) {
3184 /* Cut from the first nil or newline. */
3186 end
= strchr(buf
, '\n');
3190 cnt
= mark_printk("%s\n", buf
);
3197 static const struct file_operations tracing_max_lat_fops
= {
3198 .open
= tracing_open_generic
,
3199 .read
= tracing_max_lat_read
,
3200 .write
= tracing_max_lat_write
,
3203 static const struct file_operations tracing_ctrl_fops
= {
3204 .open
= tracing_open_generic
,
3205 .read
= tracing_ctrl_read
,
3206 .write
= tracing_ctrl_write
,
3209 static const struct file_operations set_tracer_fops
= {
3210 .open
= tracing_open_generic
,
3211 .read
= tracing_set_trace_read
,
3212 .write
= tracing_set_trace_write
,
3215 static const struct file_operations tracing_pipe_fops
= {
3216 .open
= tracing_open_pipe
,
3217 .poll
= tracing_poll_pipe
,
3218 .read
= tracing_read_pipe
,
3219 .splice_read
= tracing_splice_read_pipe
,
3220 .release
= tracing_release_pipe
,
3223 static const struct file_operations tracing_entries_fops
= {
3224 .open
= tracing_open_generic
,
3225 .read
= tracing_entries_read
,
3226 .write
= tracing_entries_write
,
3229 static const struct file_operations tracing_mark_fops
= {
3230 .open
= tracing_open_generic
,
3231 .write
= tracing_mark_write
,
3234 struct ftrace_buffer_info
{
3235 struct trace_array
*tr
;
3241 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
)
3243 int cpu
= (int)(long)inode
->i_private
;
3244 struct ftrace_buffer_info
*info
;
3246 if (tracing_disabled
)
3249 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
3253 info
->tr
= &global_trace
;
3255 info
->spare
= ring_buffer_alloc_read_page(info
->tr
->buffer
);
3256 /* Force reading ring buffer for first read */
3257 info
->read
= (unsigned int)-1;
3261 filp
->private_data
= info
;
3271 tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
3272 size_t count
, loff_t
*ppos
)
3274 struct ftrace_buffer_info
*info
= filp
->private_data
;
3282 /* Do we have previous read data to read? */
3283 if (info
->read
< PAGE_SIZE
)
3288 ret
= ring_buffer_read_page(info
->tr
->buffer
,
3295 pos
= ring_buffer_page_len(info
->spare
);
3297 if (pos
< PAGE_SIZE
)
3298 memset(info
->spare
+ pos
, 0, PAGE_SIZE
- pos
);
3301 size
= PAGE_SIZE
- info
->read
;
3305 ret
= copy_to_user(ubuf
, info
->spare
+ info
->read
, size
);
3316 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
)
3318 struct ftrace_buffer_info
*info
= file
->private_data
;
3320 ring_buffer_free_read_page(info
->tr
->buffer
, info
->spare
);
3327 struct ring_buffer
*buffer
;
3332 static void buffer_pipe_buf_release(struct pipe_inode_info
*pipe
,
3333 struct pipe_buffer
*buf
)
3335 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
3340 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
3345 static int buffer_pipe_buf_steal(struct pipe_inode_info
*pipe
,
3346 struct pipe_buffer
*buf
)
3351 static void buffer_pipe_buf_get(struct pipe_inode_info
*pipe
,
3352 struct pipe_buffer
*buf
)
3354 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
3359 /* Pipe buffer operations for a buffer. */
3360 static struct pipe_buf_operations buffer_pipe_buf_ops
= {
3362 .map
= generic_pipe_buf_map
,
3363 .unmap
= generic_pipe_buf_unmap
,
3364 .confirm
= generic_pipe_buf_confirm
,
3365 .release
= buffer_pipe_buf_release
,
3366 .steal
= buffer_pipe_buf_steal
,
3367 .get
= buffer_pipe_buf_get
,
3371 * Callback from splice_to_pipe(), if we need to release some pages
3372 * at the end of the spd in case we error'ed out in filling the pipe.
3374 static void buffer_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
3376 struct buffer_ref
*ref
=
3377 (struct buffer_ref
*)spd
->partial
[i
].private;
3382 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
3384 spd
->partial
[i
].private = 0;
3388 tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
3389 struct pipe_inode_info
*pipe
, size_t len
,
3392 struct ftrace_buffer_info
*info
= file
->private_data
;
3393 struct partial_page partial
[PIPE_BUFFERS
];
3394 struct page
*pages
[PIPE_BUFFERS
];
3395 struct splice_pipe_desc spd
= {
3399 .ops
= &buffer_pipe_buf_ops
,
3400 .spd_release
= buffer_spd_release
,
3402 struct buffer_ref
*ref
;
3407 * We can't seek on a buffer input
3409 if (unlikely(*ppos
))
3413 for (i
= 0; i
< PIPE_BUFFERS
&& len
; i
++, len
-= size
) {
3417 ref
= kzalloc(sizeof(*ref
), GFP_KERNEL
);
3421 ref
->buffer
= info
->tr
->buffer
;
3422 ref
->page
= ring_buffer_alloc_read_page(ref
->buffer
);
3428 r
= ring_buffer_read_page(ref
->buffer
, &ref
->page
,
3431 ring_buffer_free_read_page(ref
->buffer
,
3438 * zero out any left over data, this is going to
3441 size
= ring_buffer_page_len(ref
->page
);
3442 if (size
< PAGE_SIZE
)
3443 memset(ref
->page
+ size
, 0, PAGE_SIZE
- size
);
3445 page
= virt_to_page(ref
->page
);
3447 spd
.pages
[i
] = page
;
3448 spd
.partial
[i
].len
= PAGE_SIZE
;
3449 spd
.partial
[i
].offset
= 0;
3450 spd
.partial
[i
].private = (unsigned long)ref
;
3456 /* did we read anything? */
3457 if (!spd
.nr_pages
) {
3458 if (flags
& SPLICE_F_NONBLOCK
)
3466 ret
= splice_to_pipe(pipe
, &spd
);
3471 static const struct file_operations tracing_buffers_fops
= {
3472 .open
= tracing_buffers_open
,
3473 .read
= tracing_buffers_read
,
3474 .release
= tracing_buffers_release
,
3475 .splice_read
= tracing_buffers_splice_read
,
3476 .llseek
= no_llseek
,
3479 #ifdef CONFIG_DYNAMIC_FTRACE
3481 int __weak
ftrace_arch_read_dyn_info(char *buf
, int size
)
3487 tracing_read_dyn_info(struct file
*filp
, char __user
*ubuf
,
3488 size_t cnt
, loff_t
*ppos
)
3490 static char ftrace_dyn_info_buffer
[1024];
3491 static DEFINE_MUTEX(dyn_info_mutex
);
3492 unsigned long *p
= filp
->private_data
;
3493 char *buf
= ftrace_dyn_info_buffer
;
3494 int size
= ARRAY_SIZE(ftrace_dyn_info_buffer
);
3497 mutex_lock(&dyn_info_mutex
);
3498 r
= sprintf(buf
, "%ld ", *p
);
3500 r
+= ftrace_arch_read_dyn_info(buf
+r
, (size
-1)-r
);
3503 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3505 mutex_unlock(&dyn_info_mutex
);
3510 static const struct file_operations tracing_dyn_info_fops
= {
3511 .open
= tracing_open_generic
,
3512 .read
= tracing_read_dyn_info
,
3516 static struct dentry
*d_tracer
;
3518 struct dentry
*tracing_init_dentry(void)
3525 d_tracer
= debugfs_create_dir("tracing", NULL
);
3527 if (!d_tracer
&& !once
) {
3529 pr_warning("Could not create debugfs directory 'tracing'\n");
3536 static struct dentry
*d_percpu
;
3538 struct dentry
*tracing_dentry_percpu(void)
3541 struct dentry
*d_tracer
;
3546 d_tracer
= tracing_init_dentry();
3551 d_percpu
= debugfs_create_dir("per_cpu", d_tracer
);
3553 if (!d_percpu
&& !once
) {
3555 pr_warning("Could not create debugfs directory 'per_cpu'\n");
3562 static void tracing_init_debugfs_percpu(long cpu
)
3564 struct dentry
*d_percpu
= tracing_dentry_percpu();
3565 struct dentry
*entry
, *d_cpu
;
3566 /* strlen(cpu) + MAX(log10(cpu)) + '\0' */
3569 if (cpu
> 999 || cpu
< 0)
3572 sprintf(cpu_dir
, "cpu%ld", cpu
);
3573 d_cpu
= debugfs_create_dir(cpu_dir
, d_percpu
);
3575 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir
);
3579 /* per cpu trace_pipe */
3580 entry
= debugfs_create_file("trace_pipe", 0444, d_cpu
,
3581 (void *) cpu
, &tracing_pipe_fops
);
3583 pr_warning("Could not create debugfs 'trace_pipe' entry\n");
3586 entry
= debugfs_create_file("trace", 0444, d_cpu
,
3587 (void *) cpu
, &tracing_fops
);
3589 pr_warning("Could not create debugfs 'trace' entry\n");
3591 entry
= debugfs_create_file("trace_pipe_raw", 0444, d_cpu
,
3592 (void *) cpu
, &tracing_buffers_fops
);
3594 pr_warning("Could not create debugfs 'trace_pipe_raw' entry\n");
3597 #ifdef CONFIG_FTRACE_SELFTEST
3598 /* Let selftest have access to static functions in this file */
3599 #include "trace_selftest.c"
3602 struct trace_option_dentry
{
3603 struct tracer_opt
*opt
;
3604 struct tracer_flags
*flags
;
3605 struct dentry
*entry
;
3609 trace_options_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
3612 struct trace_option_dentry
*topt
= filp
->private_data
;
3615 if (topt
->flags
->val
& topt
->opt
->bit
)
3620 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
3624 trace_options_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
3627 struct trace_option_dentry
*topt
= filp
->private_data
;
3632 if (cnt
>= sizeof(buf
))
3635 if (copy_from_user(&buf
, ubuf
, cnt
))
3640 ret
= strict_strtoul(buf
, 10, &val
);
3647 /* do nothing if already cleared */
3648 if (!(topt
->flags
->val
& topt
->opt
->bit
))
3651 mutex_lock(&trace_types_lock
);
3652 if (current_trace
->set_flag
)
3653 ret
= current_trace
->set_flag(topt
->flags
->val
,
3655 mutex_unlock(&trace_types_lock
);
3658 topt
->flags
->val
&= ~topt
->opt
->bit
;
3661 /* do nothing if already set */
3662 if (topt
->flags
->val
& topt
->opt
->bit
)
3665 mutex_lock(&trace_types_lock
);
3666 if (current_trace
->set_flag
)
3667 ret
= current_trace
->set_flag(topt
->flags
->val
,
3669 mutex_unlock(&trace_types_lock
);
3672 topt
->flags
->val
|= topt
->opt
->bit
;
3685 static const struct file_operations trace_options_fops
= {
3686 .open
= tracing_open_generic
,
3687 .read
= trace_options_read
,
3688 .write
= trace_options_write
,
3692 trace_options_core_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
3695 long index
= (long)filp
->private_data
;
3698 if (trace_flags
& (1 << index
))
3703 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
3707 trace_options_core_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
3710 long index
= (long)filp
->private_data
;
3715 if (cnt
>= sizeof(buf
))
3718 if (copy_from_user(&buf
, ubuf
, cnt
))
3723 ret
= strict_strtoul(buf
, 10, &val
);
3729 trace_flags
&= ~(1 << index
);
3732 trace_flags
|= 1 << index
;
3744 static const struct file_operations trace_options_core_fops
= {
3745 .open
= tracing_open_generic
,
3746 .read
= trace_options_core_read
,
3747 .write
= trace_options_core_write
,
3750 static struct dentry
*trace_options_init_dentry(void)
3752 struct dentry
*d_tracer
;
3753 static struct dentry
*t_options
;
3758 d_tracer
= tracing_init_dentry();
3762 t_options
= debugfs_create_dir("options", d_tracer
);
3764 pr_warning("Could not create debugfs directory 'options'\n");
3772 create_trace_option_file(struct trace_option_dentry
*topt
,
3773 struct tracer_flags
*flags
,
3774 struct tracer_opt
*opt
)
3776 struct dentry
*t_options
;
3777 struct dentry
*entry
;
3779 t_options
= trace_options_init_dentry();
3783 topt
->flags
= flags
;
3786 entry
= debugfs_create_file(opt
->name
, 0644, t_options
, topt
,
3787 &trace_options_fops
);
3789 topt
->entry
= entry
;
3793 static struct trace_option_dentry
*
3794 create_trace_option_files(struct tracer
*tracer
)
3796 struct trace_option_dentry
*topts
;
3797 struct tracer_flags
*flags
;
3798 struct tracer_opt
*opts
;
3804 flags
= tracer
->flags
;
3806 if (!flags
|| !flags
->opts
)
3811 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
3814 topts
= kcalloc(cnt
+ 1, sizeof(*topts
), GFP_KERNEL
);
3818 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
3819 create_trace_option_file(&topts
[cnt
], flags
,
3826 destroy_trace_option_files(struct trace_option_dentry
*topts
)
3833 for (cnt
= 0; topts
[cnt
].opt
; cnt
++) {
3834 if (topts
[cnt
].entry
)
3835 debugfs_remove(topts
[cnt
].entry
);
3841 static struct dentry
*
3842 create_trace_option_core_file(const char *option
, long index
)
3844 struct dentry
*t_options
;
3845 struct dentry
*entry
;
3847 t_options
= trace_options_init_dentry();
3851 entry
= debugfs_create_file(option
, 0644, t_options
, (void *)index
,
3852 &trace_options_core_fops
);
3857 static __init
void create_trace_options_dir(void)
3859 struct dentry
*t_options
;
3860 struct dentry
*entry
;
3863 t_options
= trace_options_init_dentry();
3867 for (i
= 0; trace_options
[i
]; i
++) {
3868 entry
= create_trace_option_core_file(trace_options
[i
], i
);
3870 pr_warning("Could not create debugfs %s entry\n",
3875 static __init
int tracer_init_debugfs(void)
3877 struct dentry
*d_tracer
;
3878 struct dentry
*entry
;
3881 d_tracer
= tracing_init_dentry();
3883 entry
= debugfs_create_file("tracing_enabled", 0644, d_tracer
,
3884 &global_trace
, &tracing_ctrl_fops
);
3886 pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
3888 entry
= debugfs_create_file("trace_options", 0644, d_tracer
,
3889 NULL
, &tracing_iter_fops
);
3891 pr_warning("Could not create debugfs 'trace_options' entry\n");
3893 create_trace_options_dir();
3895 entry
= debugfs_create_file("tracing_cpumask", 0644, d_tracer
,
3896 NULL
, &tracing_cpumask_fops
);
3898 pr_warning("Could not create debugfs 'tracing_cpumask' entry\n");
3900 entry
= debugfs_create_file("trace", 0444, d_tracer
,
3901 (void *) TRACE_PIPE_ALL_CPU
, &tracing_fops
);
3903 pr_warning("Could not create debugfs 'trace' entry\n");
3905 entry
= debugfs_create_file("available_tracers", 0444, d_tracer
,
3906 &global_trace
, &show_traces_fops
);
3908 pr_warning("Could not create debugfs 'available_tracers' entry\n");
3910 entry
= debugfs_create_file("current_tracer", 0444, d_tracer
,
3911 &global_trace
, &set_tracer_fops
);
3913 pr_warning("Could not create debugfs 'current_tracer' entry\n");
3915 entry
= debugfs_create_file("tracing_max_latency", 0644, d_tracer
,
3916 &tracing_max_latency
,
3917 &tracing_max_lat_fops
);
3919 pr_warning("Could not create debugfs "
3920 "'tracing_max_latency' entry\n");
3922 entry
= debugfs_create_file("tracing_thresh", 0644, d_tracer
,
3923 &tracing_thresh
, &tracing_max_lat_fops
);
3925 pr_warning("Could not create debugfs "
3926 "'tracing_thresh' entry\n");
3927 entry
= debugfs_create_file("README", 0644, d_tracer
,
3928 NULL
, &tracing_readme_fops
);
3930 pr_warning("Could not create debugfs 'README' entry\n");
3932 entry
= debugfs_create_file("trace_pipe", 0444, d_tracer
,
3933 (void *) TRACE_PIPE_ALL_CPU
, &tracing_pipe_fops
);
3935 pr_warning("Could not create debugfs "
3936 "'trace_pipe' entry\n");
3938 entry
= debugfs_create_file("buffer_size_kb", 0644, d_tracer
,
3939 &global_trace
, &tracing_entries_fops
);
3941 pr_warning("Could not create debugfs "
3942 "'buffer_size_kb' entry\n");
3944 entry
= debugfs_create_file("trace_marker", 0220, d_tracer
,
3945 NULL
, &tracing_mark_fops
);
3947 pr_warning("Could not create debugfs "
3948 "'trace_marker' entry\n");
3950 #ifdef CONFIG_DYNAMIC_FTRACE
3951 entry
= debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
3952 &ftrace_update_tot_cnt
,
3953 &tracing_dyn_info_fops
);
3955 pr_warning("Could not create debugfs "
3956 "'dyn_ftrace_total_info' entry\n");
3958 #ifdef CONFIG_SYSPROF_TRACER
3959 init_tracer_sysprof_debugfs(d_tracer
);
3962 for_each_tracing_cpu(cpu
)
3963 tracing_init_debugfs_percpu(cpu
);
3968 static int trace_panic_handler(struct notifier_block
*this,
3969 unsigned long event
, void *unused
)
3971 if (ftrace_dump_on_oops
)
3976 static struct notifier_block trace_panic_notifier
= {
3977 .notifier_call
= trace_panic_handler
,
3979 .priority
= 150 /* priority: INT_MAX >= x >= 0 */
3982 static int trace_die_handler(struct notifier_block
*self
,
3988 if (ftrace_dump_on_oops
)
3997 static struct notifier_block trace_die_notifier
= {
3998 .notifier_call
= trace_die_handler
,
4003 * printk is set to max of 1024, we really don't need it that big.
4004 * Nothing should be printing 1000 characters anyway.
4006 #define TRACE_MAX_PRINT 1000
4009 * Define here KERN_TRACE so that we have one place to modify
4010 * it if we decide to change what log level the ftrace dump
4013 #define KERN_TRACE KERN_EMERG
4016 trace_printk_seq(struct trace_seq
*s
)
4018 /* Probably should print a warning here. */
4022 /* should be zero ended, but we are paranoid. */
4023 s
->buffer
[s
->len
] = 0;
4025 printk(KERN_TRACE
"%s", s
->buffer
);
4030 void ftrace_dump(void)
4032 static DEFINE_SPINLOCK(ftrace_dump_lock
);
4033 /* use static because iter can be a bit big for the stack */
4034 static struct trace_iterator iter
;
4035 static int dump_ran
;
4036 unsigned long flags
;
4040 spin_lock_irqsave(&ftrace_dump_lock
, flags
);
4046 /* No turning back! */
4050 for_each_tracing_cpu(cpu
) {
4051 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
4054 /* don't look at user memory in panic mode */
4055 trace_flags
&= ~TRACE_ITER_SYM_USEROBJ
;
4057 printk(KERN_TRACE
"Dumping ftrace buffer:\n");
4059 /* Simulate the iterator */
4060 iter
.tr
= &global_trace
;
4061 iter
.trace
= current_trace
;
4062 iter
.cpu_file
= TRACE_PIPE_ALL_CPU
;
4065 * We need to stop all tracing on all CPUS to read the
4066 * the next buffer. This is a bit expensive, but is
4067 * not done often. We fill all what we can read,
4068 * and then release the locks again.
4071 while (!trace_empty(&iter
)) {
4074 printk(KERN_TRACE
"---------------------------------\n");
4078 /* reset all but tr, trace, and overruns */
4079 memset(&iter
.seq
, 0,
4080 sizeof(struct trace_iterator
) -
4081 offsetof(struct trace_iterator
, seq
));
4082 iter
.iter_flags
|= TRACE_FILE_LAT_FMT
;
4085 if (find_next_entry_inc(&iter
) != NULL
) {
4086 print_trace_line(&iter
);
4087 trace_consume(&iter
);
4090 trace_printk_seq(&iter
.seq
);
4094 printk(KERN_TRACE
" (ftrace buffer empty)\n");
4096 printk(KERN_TRACE
"---------------------------------\n");
4099 spin_unlock_irqrestore(&ftrace_dump_lock
, flags
);
4102 __init
static int tracer_alloc_buffers(void)
4104 struct trace_array_cpu
*data
;
4109 if (!alloc_cpumask_var(&tracing_buffer_mask
, GFP_KERNEL
))
4112 if (!alloc_cpumask_var(&tracing_cpumask
, GFP_KERNEL
))
4113 goto out_free_buffer_mask
;
4115 if (!alloc_cpumask_var(&tracing_reader_cpumask
, GFP_KERNEL
))
4116 goto out_free_tracing_cpumask
;
4118 /* To save memory, keep the ring buffer size to its minimum */
4119 if (ring_buffer_expanded
)
4120 ring_buf_size
= trace_buf_size
;
4124 cpumask_copy(tracing_buffer_mask
, cpu_possible_mask
);
4125 cpumask_copy(tracing_cpumask
, cpu_all_mask
);
4126 cpumask_clear(tracing_reader_cpumask
);
4128 /* TODO: make the number of buffers hot pluggable with CPUS */
4129 global_trace
.buffer
= ring_buffer_alloc(ring_buf_size
,
4130 TRACE_BUFFER_FLAGS
);
4131 if (!global_trace
.buffer
) {
4132 printk(KERN_ERR
"tracer: failed to allocate ring buffer!\n");
4134 goto out_free_cpumask
;
4136 global_trace
.entries
= ring_buffer_size(global_trace
.buffer
);
4139 #ifdef CONFIG_TRACER_MAX_TRACE
4140 max_tr
.buffer
= ring_buffer_alloc(ring_buf_size
,
4141 TRACE_BUFFER_FLAGS
);
4142 if (!max_tr
.buffer
) {
4143 printk(KERN_ERR
"tracer: failed to allocate max ring buffer!\n");
4145 ring_buffer_free(global_trace
.buffer
);
4146 goto out_free_cpumask
;
4148 max_tr
.entries
= ring_buffer_size(max_tr
.buffer
);
4149 WARN_ON(max_tr
.entries
!= global_trace
.entries
);
4152 /* Allocate the first page for all buffers */
4153 for_each_tracing_cpu(i
) {
4154 data
= global_trace
.data
[i
] = &per_cpu(global_trace_cpu
, i
);
4155 max_tr
.data
[i
] = &per_cpu(max_data
, i
);
4158 trace_init_cmdlines();
4160 register_tracer(&nop_trace
);
4161 current_trace
= &nop_trace
;
4162 #ifdef CONFIG_BOOT_TRACER
4163 register_tracer(&boot_tracer
);
4165 /* All seems OK, enable tracing */
4166 tracing_disabled
= 0;
4168 atomic_notifier_chain_register(&panic_notifier_list
,
4169 &trace_panic_notifier
);
4171 register_die_notifier(&trace_die_notifier
);
4176 free_cpumask_var(tracing_reader_cpumask
);
4177 out_free_tracing_cpumask
:
4178 free_cpumask_var(tracing_cpumask
);
4179 out_free_buffer_mask
:
4180 free_cpumask_var(tracing_buffer_mask
);
4185 __init
static int clear_boot_tracer(void)
4188 * The default tracer at boot buffer is an init section.
4189 * This function is called in lateinit. If we did not
4190 * find the boot tracer, then clear it out, to prevent
4191 * later registration from accessing the buffer that is
4192 * about to be freed.
4194 if (!default_bootup_tracer
)
4197 printk(KERN_INFO
"ftrace bootup tracer '%s' not registered.\n",
4198 default_bootup_tracer
);
4199 default_bootup_tracer
= NULL
;
4204 early_initcall(tracer_alloc_buffers
);
4205 fs_initcall(tracer_init_debugfs
);
4206 late_initcall(clear_boot_tracer
);