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/utsrelease.h>
15 #include <linux/kallsyms.h>
16 #include <linux/seq_file.h>
17 #include <linux/notifier.h>
18 #include <linux/debugfs.h>
19 #include <linux/pagemap.h>
20 #include <linux/hardirq.h>
21 #include <linux/linkage.h>
22 #include <linux/uaccess.h>
23 #include <linux/ftrace.h>
24 #include <linux/module.h>
25 #include <linux/percpu.h>
26 #include <linux/kdebug.h>
27 #include <linux/ctype.h>
28 #include <linux/init.h>
29 #include <linux/poll.h>
30 #include <linux/gfp.h>
32 #include <linux/kprobes.h>
33 #include <linux/writeback.h>
35 #include <linux/stacktrace.h>
36 #include <linux/ring_buffer.h>
37 #include <linux/irqflags.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 * We need to change this state when a selftest is running.
49 * A selftest will lurk into the ring-buffer to count the
50 * entries inserted during the selftest although some concurrent
51 * insertions into the ring-buffer such as ftrace_printk could occurred
52 * at the same time, giving false positive or negative results.
54 static bool __read_mostly tracing_selftest_running
;
57 * If a tracer is running, we do not want to run SELFTEST.
59 static bool __read_mostly tracing_selftest_disabled
;
61 /* For tracers that don't implement custom flags */
62 static struct tracer_opt dummy_tracer_opt
[] = {
66 static struct tracer_flags dummy_tracer_flags
= {
68 .opts
= dummy_tracer_opt
71 static int dummy_set_flag(u32 old_flags
, u32 bit
, int set
)
77 * Kill all tracing for good (never come back).
78 * It is initialized to 1 but will turn to zero if the initialization
79 * of the tracer is successful. But that is the only place that sets
82 int tracing_disabled
= 1;
84 static DEFINE_PER_CPU(local_t
, ftrace_cpu_disabled
);
86 static inline void ftrace_disable_cpu(void)
89 local_inc(&__get_cpu_var(ftrace_cpu_disabled
));
92 static inline void ftrace_enable_cpu(void)
94 local_dec(&__get_cpu_var(ftrace_cpu_disabled
));
98 static cpumask_var_t __read_mostly tracing_buffer_mask
;
100 #define for_each_tracing_cpu(cpu) \
101 for_each_cpu(cpu, tracing_buffer_mask)
104 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
106 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
107 * is set, then ftrace_dump is called. This will output the contents
108 * of the ftrace buffers to the console. This is very useful for
109 * capturing traces that lead to crashes and outputing it to a
112 * It is default off, but you can enable it with either specifying
113 * "ftrace_dump_on_oops" in the kernel command line, or setting
114 * /proc/sys/kernel/ftrace_dump_on_oops to true.
116 int ftrace_dump_on_oops
;
118 static int tracing_set_tracer(const char *buf
);
120 #define BOOTUP_TRACER_SIZE 100
121 static char bootup_tracer_buf
[BOOTUP_TRACER_SIZE
] __initdata
;
122 static char *default_bootup_tracer
;
124 static int __init
set_ftrace(char *str
)
126 strncpy(bootup_tracer_buf
, str
, BOOTUP_TRACER_SIZE
);
127 default_bootup_tracer
= bootup_tracer_buf
;
130 __setup("ftrace=", set_ftrace
);
132 static int __init
set_ftrace_dump_on_oops(char *str
)
134 ftrace_dump_on_oops
= 1;
137 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops
);
140 ns2usecs(cycle_t nsec
)
147 cycle_t
ftrace_now(int cpu
)
149 u64 ts
= ring_buffer_time_stamp(cpu
);
150 ring_buffer_normalize_time_stamp(cpu
, &ts
);
155 * The global_trace is the descriptor that holds the tracing
156 * buffers for the live tracing. For each CPU, it contains
157 * a link list of pages that will store trace entries. The
158 * page descriptor of the pages in the memory is used to hold
159 * the link list by linking the lru item in the page descriptor
160 * to each of the pages in the buffer per CPU.
162 * For each active CPU there is a data field that holds the
163 * pages for the buffer for that CPU. Each CPU has the same number
164 * of pages allocated for its buffer.
166 static struct trace_array global_trace
;
168 static DEFINE_PER_CPU(struct trace_array_cpu
, global_trace_cpu
);
171 * The max_tr is used to snapshot the global_trace when a maximum
172 * latency is reached. Some tracers will use this to store a maximum
173 * trace while it continues examining live traces.
175 * The buffers for the max_tr are set up the same as the global_trace.
176 * When a snapshot is taken, the link list of the max_tr is swapped
177 * with the link list of the global_trace and the buffers are reset for
178 * the global_trace so the tracing can continue.
180 static struct trace_array max_tr
;
182 static DEFINE_PER_CPU(struct trace_array_cpu
, max_data
);
184 /* tracer_enabled is used to toggle activation of a tracer */
185 static int tracer_enabled
= 1;
188 * tracing_is_enabled - return tracer_enabled status
190 * This function is used by other tracers to know the status
191 * of the tracer_enabled flag. Tracers may use this function
192 * to know if it should enable their features when starting
193 * up. See irqsoff tracer for an example (start_irqsoff_tracer).
195 int tracing_is_enabled(void)
197 return tracer_enabled
;
201 * trace_buf_size is the size in bytes that is allocated
202 * for a buffer. Note, the number of bytes is always rounded
205 * This number is purposely set to a low number of 16384.
206 * If the dump on oops happens, it will be much appreciated
207 * to not have to wait for all that output. Anyway this can be
208 * boot time and run time configurable.
210 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
212 static unsigned long trace_buf_size
= TRACE_BUF_SIZE_DEFAULT
;
214 /* trace_types holds a link list of available tracers. */
215 static struct tracer
*trace_types __read_mostly
;
217 /* current_trace points to the tracer that is currently active */
218 static struct tracer
*current_trace __read_mostly
;
221 * max_tracer_type_len is used to simplify the allocating of
222 * buffers to read userspace tracer names. We keep track of
223 * the longest tracer name registered.
225 static int max_tracer_type_len
;
228 * trace_types_lock is used to protect the trace_types list.
229 * This lock is also used to keep user access serialized.
230 * Accesses from userspace will grab this lock while userspace
231 * activities happen inside the kernel.
233 static DEFINE_MUTEX(trace_types_lock
);
235 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
236 static DECLARE_WAIT_QUEUE_HEAD(trace_wait
);
238 /* trace_flags holds trace_options default values */
239 unsigned long trace_flags
= TRACE_ITER_PRINT_PARENT
| TRACE_ITER_PRINTK
|
240 TRACE_ITER_ANNOTATE
| TRACE_ITER_CONTEXT_INFO
;
243 * trace_wake_up - wake up tasks waiting for trace input
245 * Simply wakes up any task that is blocked on the trace_wait
246 * queue. These is used with trace_poll for tasks polling the trace.
248 void trace_wake_up(void)
251 * The runqueue_is_locked() can fail, but this is the best we
254 if (!(trace_flags
& TRACE_ITER_BLOCK
) && !runqueue_is_locked())
255 wake_up(&trace_wait
);
258 static int __init
set_buf_size(char *str
)
260 unsigned long buf_size
;
265 ret
= strict_strtoul(str
, 0, &buf_size
);
266 /* nr_entries can not be zero */
267 if (ret
< 0 || buf_size
== 0)
269 trace_buf_size
= buf_size
;
272 __setup("trace_buf_size=", set_buf_size
);
274 unsigned long nsecs_to_usecs(unsigned long nsecs
)
279 /* These must match the bit postions in trace_iterator_flags */
280 static const char *trace_options
[] = {
303 * ftrace_max_lock is used to protect the swapping of buffers
304 * when taking a max snapshot. The buffers themselves are
305 * protected by per_cpu spinlocks. But the action of the swap
306 * needs its own lock.
308 * This is defined as a raw_spinlock_t in order to help
309 * with performance when lockdep debugging is enabled.
311 static raw_spinlock_t ftrace_max_lock
=
312 (raw_spinlock_t
)__RAW_SPIN_LOCK_UNLOCKED
;
315 * Copy the new maximum trace into the separate maximum-trace
316 * structure. (this way the maximum trace is permanently saved,
317 * for later retrieval via /debugfs/tracing/latency_trace)
320 __update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
322 struct trace_array_cpu
*data
= tr
->data
[cpu
];
325 max_tr
.time_start
= data
->preempt_timestamp
;
327 data
= max_tr
.data
[cpu
];
328 data
->saved_latency
= tracing_max_latency
;
330 memcpy(data
->comm
, tsk
->comm
, TASK_COMM_LEN
);
331 data
->pid
= tsk
->pid
;
332 data
->uid
= task_uid(tsk
);
333 data
->nice
= tsk
->static_prio
- 20 - MAX_RT_PRIO
;
334 data
->policy
= tsk
->policy
;
335 data
->rt_priority
= tsk
->rt_priority
;
337 /* record this tasks comm */
338 tracing_record_cmdline(current
);
342 trace_seq_reset(struct trace_seq
*s
)
348 ssize_t
trace_seq_to_user(struct trace_seq
*s
, char __user
*ubuf
, size_t cnt
)
353 if (s
->len
<= s
->readpos
)
356 len
= s
->len
- s
->readpos
;
359 ret
= copy_to_user(ubuf
, s
->buffer
+ s
->readpos
, cnt
);
368 trace_print_seq(struct seq_file
*m
, struct trace_seq
*s
)
370 int len
= s
->len
>= PAGE_SIZE
? PAGE_SIZE
- 1 : s
->len
;
373 seq_puts(m
, s
->buffer
);
379 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
381 * @tsk: the task with the latency
382 * @cpu: The cpu that initiated the trace.
384 * Flip the buffers between the @tr and the max_tr and record information
385 * about which task was the cause of this latency.
388 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
390 struct ring_buffer
*buf
= tr
->buffer
;
392 WARN_ON_ONCE(!irqs_disabled());
393 __raw_spin_lock(&ftrace_max_lock
);
395 tr
->buffer
= max_tr
.buffer
;
398 ftrace_disable_cpu();
399 ring_buffer_reset(tr
->buffer
);
402 __update_max_tr(tr
, tsk
, cpu
);
403 __raw_spin_unlock(&ftrace_max_lock
);
407 * update_max_tr_single - only copy one trace over, and reset the rest
409 * @tsk - task with the latency
410 * @cpu - the cpu of the buffer to copy.
412 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
415 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
419 WARN_ON_ONCE(!irqs_disabled());
420 __raw_spin_lock(&ftrace_max_lock
);
422 ftrace_disable_cpu();
424 ring_buffer_reset(max_tr
.buffer
);
425 ret
= ring_buffer_swap_cpu(max_tr
.buffer
, tr
->buffer
, cpu
);
429 WARN_ON_ONCE(ret
&& ret
!= -EAGAIN
);
431 __update_max_tr(tr
, tsk
, cpu
);
432 __raw_spin_unlock(&ftrace_max_lock
);
436 * register_tracer - register a tracer with the ftrace system.
437 * @type - the plugin for the tracer
439 * Register a new plugin tracer.
441 int register_tracer(struct tracer
*type
)
448 pr_info("Tracer must have a name\n");
453 * When this gets called we hold the BKL which means that
454 * preemption is disabled. Various trace selftests however
455 * need to disable and enable preemption for successful tests.
456 * So we drop the BKL here and grab it after the tests again.
459 mutex_lock(&trace_types_lock
);
461 tracing_selftest_running
= true;
463 for (t
= trace_types
; t
; t
= t
->next
) {
464 if (strcmp(type
->name
, t
->name
) == 0) {
466 pr_info("Trace %s already registered\n",
474 type
->set_flag
= &dummy_set_flag
;
476 type
->flags
= &dummy_tracer_flags
;
478 if (!type
->flags
->opts
)
479 type
->flags
->opts
= dummy_tracer_opt
;
481 #ifdef CONFIG_FTRACE_STARTUP_TEST
482 if (type
->selftest
&& !tracing_selftest_disabled
) {
483 struct tracer
*saved_tracer
= current_trace
;
484 struct trace_array
*tr
= &global_trace
;
488 * Run a selftest on this tracer.
489 * Here we reset the trace buffer, and set the current
490 * tracer to be this tracer. The tracer can then run some
491 * internal tracing to verify that everything is in order.
492 * If we fail, we do not register this tracer.
494 for_each_tracing_cpu(i
)
495 tracing_reset(tr
, i
);
497 current_trace
= type
;
498 /* the test is responsible for initializing and enabling */
499 pr_info("Testing tracer %s: ", type
->name
);
500 ret
= type
->selftest(type
, tr
);
501 /* the test is responsible for resetting too */
502 current_trace
= saved_tracer
;
504 printk(KERN_CONT
"FAILED!\n");
507 /* Only reset on passing, to avoid touching corrupted buffers */
508 for_each_tracing_cpu(i
)
509 tracing_reset(tr
, i
);
511 printk(KERN_CONT
"PASSED\n");
515 type
->next
= trace_types
;
517 len
= strlen(type
->name
);
518 if (len
> max_tracer_type_len
)
519 max_tracer_type_len
= len
;
522 tracing_selftest_running
= false;
523 mutex_unlock(&trace_types_lock
);
525 if (ret
|| !default_bootup_tracer
)
528 if (strncmp(default_bootup_tracer
, type
->name
, BOOTUP_TRACER_SIZE
))
531 printk(KERN_INFO
"Starting tracer '%s'\n", type
->name
);
532 /* Do we want this tracer to start on bootup? */
533 tracing_set_tracer(type
->name
);
534 default_bootup_tracer
= NULL
;
535 /* disable other selftests, since this will break it. */
536 tracing_selftest_disabled
= 1;
537 #ifdef CONFIG_FTRACE_STARTUP_TEST
538 printk(KERN_INFO
"Disabling FTRACE selftests due to running tracer '%s'\n",
547 void unregister_tracer(struct tracer
*type
)
552 mutex_lock(&trace_types_lock
);
553 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
557 pr_info("Trace %s not registered\n", type
->name
);
563 if (type
== current_trace
&& tracer_enabled
) {
566 if (current_trace
->stop
)
567 current_trace
->stop(&global_trace
);
568 current_trace
= &nop_trace
;
571 if (strlen(type
->name
) != max_tracer_type_len
)
574 max_tracer_type_len
= 0;
575 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
576 len
= strlen((*t
)->name
);
577 if (len
> max_tracer_type_len
)
578 max_tracer_type_len
= len
;
581 mutex_unlock(&trace_types_lock
);
584 void tracing_reset(struct trace_array
*tr
, int cpu
)
586 ftrace_disable_cpu();
587 ring_buffer_reset_cpu(tr
->buffer
, cpu
);
591 void tracing_reset_online_cpus(struct trace_array
*tr
)
595 tr
->time_start
= ftrace_now(tr
->cpu
);
597 for_each_online_cpu(cpu
)
598 tracing_reset(tr
, cpu
);
601 #define SAVED_CMDLINES 128
602 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
603 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
604 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
605 static int cmdline_idx
;
606 static DEFINE_SPINLOCK(trace_cmdline_lock
);
608 /* temporary disable recording */
609 atomic_t trace_record_cmdline_disabled __read_mostly
;
611 static void trace_init_cmdlines(void)
613 memset(&map_pid_to_cmdline
, -1, sizeof(map_pid_to_cmdline
));
614 memset(&map_cmdline_to_pid
, -1, sizeof(map_cmdline_to_pid
));
618 static int trace_stop_count
;
619 static DEFINE_SPINLOCK(tracing_start_lock
);
622 * ftrace_off_permanent - disable all ftrace code permanently
624 * This should only be called when a serious anomally has
625 * been detected. This will turn off the function tracing,
626 * ring buffers, and other tracing utilites. It takes no
627 * locks and can be called from any context.
629 void ftrace_off_permanent(void)
631 tracing_disabled
= 1;
633 tracing_off_permanent();
637 * tracing_start - quick start of the tracer
639 * If tracing is enabled but was stopped by tracing_stop,
640 * this will start the tracer back up.
642 void tracing_start(void)
644 struct ring_buffer
*buffer
;
647 if (tracing_disabled
)
650 spin_lock_irqsave(&tracing_start_lock
, flags
);
651 if (--trace_stop_count
) {
652 if (trace_stop_count
< 0) {
653 /* Someone screwed up their debugging */
655 trace_stop_count
= 0;
661 buffer
= global_trace
.buffer
;
663 ring_buffer_record_enable(buffer
);
665 buffer
= max_tr
.buffer
;
667 ring_buffer_record_enable(buffer
);
671 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
675 * tracing_stop - quick stop of the tracer
677 * Light weight way to stop tracing. Use in conjunction with
680 void tracing_stop(void)
682 struct ring_buffer
*buffer
;
686 spin_lock_irqsave(&tracing_start_lock
, flags
);
687 if (trace_stop_count
++)
690 buffer
= global_trace
.buffer
;
692 ring_buffer_record_disable(buffer
);
694 buffer
= max_tr
.buffer
;
696 ring_buffer_record_disable(buffer
);
699 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
702 void trace_stop_cmdline_recording(void);
704 static void trace_save_cmdline(struct task_struct
*tsk
)
709 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
713 * It's not the end of the world if we don't get
714 * the lock, but we also don't want to spin
715 * nor do we want to disable interrupts,
716 * so if we miss here, then better luck next time.
718 if (!spin_trylock(&trace_cmdline_lock
))
721 idx
= map_pid_to_cmdline
[tsk
->pid
];
722 if (idx
>= SAVED_CMDLINES
) {
723 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
725 map
= map_cmdline_to_pid
[idx
];
726 if (map
<= PID_MAX_DEFAULT
)
727 map_pid_to_cmdline
[map
] = (unsigned)-1;
729 map_pid_to_cmdline
[tsk
->pid
] = idx
;
734 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
736 spin_unlock(&trace_cmdline_lock
);
739 char *trace_find_cmdline(int pid
)
741 char *cmdline
= "<...>";
747 if (pid
> PID_MAX_DEFAULT
)
750 map
= map_pid_to_cmdline
[pid
];
751 if (map
>= SAVED_CMDLINES
)
754 cmdline
= saved_cmdlines
[map
];
760 void tracing_record_cmdline(struct task_struct
*tsk
)
762 if (atomic_read(&trace_record_cmdline_disabled
))
765 trace_save_cmdline(tsk
);
769 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
,
772 struct task_struct
*tsk
= current
;
774 entry
->preempt_count
= pc
& 0xff;
775 entry
->pid
= (tsk
) ? tsk
->pid
: 0;
776 entry
->tgid
= (tsk
) ? tsk
->tgid
: 0;
778 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
779 (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
781 TRACE_FLAG_IRQS_NOSUPPORT
|
783 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
784 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
785 (need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0);
788 struct ring_buffer_event
*trace_buffer_lock_reserve(struct trace_array
*tr
,
791 unsigned long flags
, int pc
)
793 struct ring_buffer_event
*event
;
795 event
= ring_buffer_lock_reserve(tr
->buffer
, len
);
797 struct trace_entry
*ent
= ring_buffer_event_data(event
);
799 tracing_generic_entry_update(ent
, flags
, pc
);
805 static void ftrace_trace_stack(struct trace_array
*tr
,
806 unsigned long flags
, int skip
, int pc
);
807 static void ftrace_trace_userstack(struct trace_array
*tr
,
808 unsigned long flags
, int pc
);
810 void trace_buffer_unlock_commit(struct trace_array
*tr
,
811 struct ring_buffer_event
*event
,
812 unsigned long flags
, int pc
)
814 ring_buffer_unlock_commit(tr
->buffer
, event
);
816 ftrace_trace_stack(tr
, flags
, 6, pc
);
817 ftrace_trace_userstack(tr
, flags
, pc
);
822 trace_function(struct trace_array
*tr
,
823 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
826 struct ring_buffer_event
*event
;
827 struct ftrace_entry
*entry
;
829 /* If we are reading the ring buffer, don't trace */
830 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
833 event
= trace_buffer_lock_reserve(tr
, TRACE_FN
, sizeof(*entry
),
837 entry
= ring_buffer_event_data(event
);
839 entry
->parent_ip
= parent_ip
;
840 ring_buffer_unlock_commit(tr
->buffer
, event
);
843 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
844 static void __trace_graph_entry(struct trace_array
*tr
,
845 struct ftrace_graph_ent
*trace
,
849 struct ring_buffer_event
*event
;
850 struct ftrace_graph_ent_entry
*entry
;
852 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
855 event
= trace_buffer_lock_reserve(&global_trace
, TRACE_GRAPH_ENT
,
856 sizeof(*entry
), flags
, pc
);
859 entry
= ring_buffer_event_data(event
);
860 entry
->graph_ent
= *trace
;
861 ring_buffer_unlock_commit(global_trace
.buffer
, event
);
864 static void __trace_graph_return(struct trace_array
*tr
,
865 struct ftrace_graph_ret
*trace
,
869 struct ring_buffer_event
*event
;
870 struct ftrace_graph_ret_entry
*entry
;
872 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
875 event
= trace_buffer_lock_reserve(&global_trace
, TRACE_GRAPH_RET
,
876 sizeof(*entry
), flags
, pc
);
879 entry
= ring_buffer_event_data(event
);
881 ring_buffer_unlock_commit(global_trace
.buffer
, event
);
886 ftrace(struct trace_array
*tr
, struct trace_array_cpu
*data
,
887 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
890 if (likely(!atomic_read(&data
->disabled
)))
891 trace_function(tr
, ip
, parent_ip
, flags
, pc
);
894 static void __ftrace_trace_stack(struct trace_array
*tr
,
898 #ifdef CONFIG_STACKTRACE
899 struct ring_buffer_event
*event
;
900 struct stack_entry
*entry
;
901 struct stack_trace trace
;
903 event
= trace_buffer_lock_reserve(tr
, TRACE_STACK
,
904 sizeof(*entry
), flags
, pc
);
907 entry
= ring_buffer_event_data(event
);
908 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
910 trace
.nr_entries
= 0;
911 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
913 trace
.entries
= entry
->caller
;
915 save_stack_trace(&trace
);
916 ring_buffer_unlock_commit(tr
->buffer
, event
);
920 static void ftrace_trace_stack(struct trace_array
*tr
,
924 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
927 __ftrace_trace_stack(tr
, flags
, skip
, pc
);
930 void __trace_stack(struct trace_array
*tr
,
934 __ftrace_trace_stack(tr
, flags
, skip
, pc
);
937 static void ftrace_trace_userstack(struct trace_array
*tr
,
938 unsigned long flags
, int pc
)
940 #ifdef CONFIG_STACKTRACE
941 struct ring_buffer_event
*event
;
942 struct userstack_entry
*entry
;
943 struct stack_trace trace
;
945 if (!(trace_flags
& TRACE_ITER_USERSTACKTRACE
))
948 event
= trace_buffer_lock_reserve(tr
, TRACE_USER_STACK
,
949 sizeof(*entry
), flags
, pc
);
952 entry
= ring_buffer_event_data(event
);
954 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
956 trace
.nr_entries
= 0;
957 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
959 trace
.entries
= entry
->caller
;
961 save_stack_trace_user(&trace
);
962 ring_buffer_unlock_commit(tr
->buffer
, event
);
966 void __trace_userstack(struct trace_array
*tr
, unsigned long flags
)
968 ftrace_trace_userstack(tr
, flags
, preempt_count());
972 ftrace_trace_special(void *__tr
,
973 unsigned long arg1
, unsigned long arg2
, unsigned long arg3
,
976 struct ring_buffer_event
*event
;
977 struct trace_array
*tr
= __tr
;
978 struct special_entry
*entry
;
980 event
= trace_buffer_lock_reserve(tr
, TRACE_SPECIAL
,
981 sizeof(*entry
), 0, pc
);
984 entry
= ring_buffer_event_data(event
);
988 trace_buffer_unlock_commit(tr
, event
, 0, pc
);
992 __trace_special(void *__tr
, void *__data
,
993 unsigned long arg1
, unsigned long arg2
, unsigned long arg3
)
995 ftrace_trace_special(__tr
, arg1
, arg2
, arg3
, preempt_count());
999 tracing_sched_switch_trace(struct trace_array
*tr
,
1000 struct task_struct
*prev
,
1001 struct task_struct
*next
,
1002 unsigned long flags
, int pc
)
1004 struct ring_buffer_event
*event
;
1005 struct ctx_switch_entry
*entry
;
1007 event
= trace_buffer_lock_reserve(tr
, TRACE_CTX
,
1008 sizeof(*entry
), flags
, pc
);
1011 entry
= ring_buffer_event_data(event
);
1012 entry
->prev_pid
= prev
->pid
;
1013 entry
->prev_prio
= prev
->prio
;
1014 entry
->prev_state
= prev
->state
;
1015 entry
->next_pid
= next
->pid
;
1016 entry
->next_prio
= next
->prio
;
1017 entry
->next_state
= next
->state
;
1018 entry
->next_cpu
= task_cpu(next
);
1019 trace_buffer_unlock_commit(tr
, event
, flags
, pc
);
1023 tracing_sched_wakeup_trace(struct trace_array
*tr
,
1024 struct task_struct
*wakee
,
1025 struct task_struct
*curr
,
1026 unsigned long flags
, int pc
)
1028 struct ring_buffer_event
*event
;
1029 struct ctx_switch_entry
*entry
;
1031 event
= trace_buffer_lock_reserve(tr
, TRACE_WAKE
,
1032 sizeof(*entry
), flags
, pc
);
1035 entry
= ring_buffer_event_data(event
);
1036 entry
->prev_pid
= curr
->pid
;
1037 entry
->prev_prio
= curr
->prio
;
1038 entry
->prev_state
= curr
->state
;
1039 entry
->next_pid
= wakee
->pid
;
1040 entry
->next_prio
= wakee
->prio
;
1041 entry
->next_state
= wakee
->state
;
1042 entry
->next_cpu
= task_cpu(wakee
);
1043 trace_buffer_unlock_commit(tr
, event
, flags
, pc
);
1047 ftrace_special(unsigned long arg1
, unsigned long arg2
, unsigned long arg3
)
1049 struct trace_array
*tr
= &global_trace
;
1050 struct trace_array_cpu
*data
;
1051 unsigned long flags
;
1055 if (tracing_disabled
)
1058 pc
= preempt_count();
1059 local_irq_save(flags
);
1060 cpu
= raw_smp_processor_id();
1061 data
= tr
->data
[cpu
];
1063 if (likely(atomic_inc_return(&data
->disabled
) == 1))
1064 ftrace_trace_special(tr
, arg1
, arg2
, arg3
, pc
);
1066 atomic_dec(&data
->disabled
);
1067 local_irq_restore(flags
);
1070 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1071 int trace_graph_entry(struct ftrace_graph_ent
*trace
)
1073 struct trace_array
*tr
= &global_trace
;
1074 struct trace_array_cpu
*data
;
1075 unsigned long flags
;
1080 if (!ftrace_trace_task(current
))
1083 if (!ftrace_graph_addr(trace
->func
))
1086 local_irq_save(flags
);
1087 cpu
= raw_smp_processor_id();
1088 data
= tr
->data
[cpu
];
1089 disabled
= atomic_inc_return(&data
->disabled
);
1090 if (likely(disabled
== 1)) {
1091 pc
= preempt_count();
1092 __trace_graph_entry(tr
, trace
, flags
, pc
);
1094 /* Only do the atomic if it is not already set */
1095 if (!test_tsk_trace_graph(current
))
1096 set_tsk_trace_graph(current
);
1097 atomic_dec(&data
->disabled
);
1098 local_irq_restore(flags
);
1103 void trace_graph_return(struct ftrace_graph_ret
*trace
)
1105 struct trace_array
*tr
= &global_trace
;
1106 struct trace_array_cpu
*data
;
1107 unsigned long flags
;
1112 local_irq_save(flags
);
1113 cpu
= raw_smp_processor_id();
1114 data
= tr
->data
[cpu
];
1115 disabled
= atomic_inc_return(&data
->disabled
);
1116 if (likely(disabled
== 1)) {
1117 pc
= preempt_count();
1118 __trace_graph_return(tr
, trace
, flags
, pc
);
1121 clear_tsk_trace_graph(current
);
1122 atomic_dec(&data
->disabled
);
1123 local_irq_restore(flags
);
1125 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1127 enum trace_file_type
{
1128 TRACE_FILE_LAT_FMT
= 1,
1129 TRACE_FILE_ANNOTATE
= 2,
1132 static void trace_iterator_increment(struct trace_iterator
*iter
)
1134 /* Don't allow ftrace to trace into the ring buffers */
1135 ftrace_disable_cpu();
1138 if (iter
->buffer_iter
[iter
->cpu
])
1139 ring_buffer_read(iter
->buffer_iter
[iter
->cpu
], NULL
);
1141 ftrace_enable_cpu();
1144 static struct trace_entry
*
1145 peek_next_entry(struct trace_iterator
*iter
, int cpu
, u64
*ts
)
1147 struct ring_buffer_event
*event
;
1148 struct ring_buffer_iter
*buf_iter
= iter
->buffer_iter
[cpu
];
1150 /* Don't allow ftrace to trace into the ring buffers */
1151 ftrace_disable_cpu();
1154 event
= ring_buffer_iter_peek(buf_iter
, ts
);
1156 event
= ring_buffer_peek(iter
->tr
->buffer
, cpu
, ts
);
1158 ftrace_enable_cpu();
1160 return event
? ring_buffer_event_data(event
) : NULL
;
1163 static struct trace_entry
*
1164 __find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
, u64
*ent_ts
)
1166 struct ring_buffer
*buffer
= iter
->tr
->buffer
;
1167 struct trace_entry
*ent
, *next
= NULL
;
1168 u64 next_ts
= 0, ts
;
1172 for_each_tracing_cpu(cpu
) {
1174 if (ring_buffer_empty_cpu(buffer
, cpu
))
1177 ent
= peek_next_entry(iter
, cpu
, &ts
);
1180 * Pick the entry with the smallest timestamp:
1182 if (ent
&& (!next
|| ts
< next_ts
)) {
1190 *ent_cpu
= next_cpu
;
1198 /* Find the next real entry, without updating the iterator itself */
1199 struct trace_entry
*trace_find_next_entry(struct trace_iterator
*iter
,
1200 int *ent_cpu
, u64
*ent_ts
)
1202 return __find_next_entry(iter
, ent_cpu
, ent_ts
);
1205 /* Find the next real entry, and increment the iterator to the next entry */
1206 static void *find_next_entry_inc(struct trace_iterator
*iter
)
1208 iter
->ent
= __find_next_entry(iter
, &iter
->cpu
, &iter
->ts
);
1211 trace_iterator_increment(iter
);
1213 return iter
->ent
? iter
: NULL
;
1216 static void trace_consume(struct trace_iterator
*iter
)
1218 /* Don't allow ftrace to trace into the ring buffers */
1219 ftrace_disable_cpu();
1220 ring_buffer_consume(iter
->tr
->buffer
, iter
->cpu
, &iter
->ts
);
1221 ftrace_enable_cpu();
1224 static void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1226 struct trace_iterator
*iter
= m
->private;
1232 /* can't go backwards */
1237 ent
= find_next_entry_inc(iter
);
1241 while (ent
&& iter
->idx
< i
)
1242 ent
= find_next_entry_inc(iter
);
1249 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
1251 struct trace_iterator
*iter
= m
->private;
1256 mutex_lock(&trace_types_lock
);
1258 if (!current_trace
|| current_trace
!= iter
->trace
) {
1259 mutex_unlock(&trace_types_lock
);
1263 atomic_inc(&trace_record_cmdline_disabled
);
1265 if (*pos
!= iter
->pos
) {
1270 ftrace_disable_cpu();
1272 for_each_tracing_cpu(cpu
) {
1273 ring_buffer_iter_reset(iter
->buffer_iter
[cpu
]);
1276 ftrace_enable_cpu();
1278 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
1283 p
= s_next(m
, p
, &l
);
1289 static void s_stop(struct seq_file
*m
, void *p
)
1291 atomic_dec(&trace_record_cmdline_disabled
);
1292 mutex_unlock(&trace_types_lock
);
1295 static void print_lat_help_header(struct seq_file
*m
)
1297 seq_puts(m
, "# _------=> CPU# \n");
1298 seq_puts(m
, "# / _-----=> irqs-off \n");
1299 seq_puts(m
, "# | / _----=> need-resched \n");
1300 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
1301 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
1302 seq_puts(m
, "# |||| / \n");
1303 seq_puts(m
, "# ||||| delay \n");
1304 seq_puts(m
, "# cmd pid ||||| time | caller \n");
1305 seq_puts(m
, "# \\ / ||||| \\ | / \n");
1308 static void print_func_help_header(struct seq_file
*m
)
1310 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1311 seq_puts(m
, "# | | | | |\n");
1316 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
1318 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1319 struct trace_array
*tr
= iter
->tr
;
1320 struct trace_array_cpu
*data
= tr
->data
[tr
->cpu
];
1321 struct tracer
*type
= current_trace
;
1322 unsigned long total
;
1323 unsigned long entries
;
1324 const char *name
= "preemption";
1329 entries
= ring_buffer_entries(iter
->tr
->buffer
);
1331 ring_buffer_overruns(iter
->tr
->buffer
);
1333 seq_printf(m
, "%s latency trace v1.1.5 on %s\n",
1335 seq_puts(m
, "-----------------------------------"
1336 "---------------------------------\n");
1337 seq_printf(m
, " latency: %lu us, #%lu/%lu, CPU#%d |"
1338 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1339 nsecs_to_usecs(data
->saved_latency
),
1343 #if defined(CONFIG_PREEMPT_NONE)
1345 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1347 #elif defined(CONFIG_PREEMPT)
1352 /* These are reserved for later use */
1355 seq_printf(m
, " #P:%d)\n", num_online_cpus());
1359 seq_puts(m
, " -----------------\n");
1360 seq_printf(m
, " | task: %.16s-%d "
1361 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1362 data
->comm
, data
->pid
, data
->uid
, data
->nice
,
1363 data
->policy
, data
->rt_priority
);
1364 seq_puts(m
, " -----------------\n");
1366 if (data
->critical_start
) {
1367 seq_puts(m
, " => started at: ");
1368 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
1369 trace_print_seq(m
, &iter
->seq
);
1370 seq_puts(m
, "\n => ended at: ");
1371 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
1372 trace_print_seq(m
, &iter
->seq
);
1379 static void test_cpu_buff_start(struct trace_iterator
*iter
)
1381 struct trace_seq
*s
= &iter
->seq
;
1383 if (!(trace_flags
& TRACE_ITER_ANNOTATE
))
1386 if (!(iter
->iter_flags
& TRACE_FILE_ANNOTATE
))
1389 if (cpumask_test_cpu(iter
->cpu
, iter
->started
))
1392 cpumask_set_cpu(iter
->cpu
, iter
->started
);
1393 trace_seq_printf(s
, "##### CPU %u buffer started ####\n", iter
->cpu
);
1396 static enum print_line_t
print_lat_fmt(struct trace_iterator
*iter
)
1398 struct trace_seq
*s
= &iter
->seq
;
1399 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1400 struct trace_event
*event
;
1401 struct trace_entry
*entry
= iter
->ent
;
1403 test_cpu_buff_start(iter
);
1405 event
= ftrace_find_event(entry
->type
);
1407 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1408 if (!trace_print_lat_context(iter
))
1413 return event
->latency_trace(iter
, sym_flags
);
1415 if (!trace_seq_printf(s
, "Unknown type %d\n", entry
->type
))
1418 return TRACE_TYPE_HANDLED
;
1420 return TRACE_TYPE_PARTIAL_LINE
;
1423 static enum print_line_t
print_trace_fmt(struct trace_iterator
*iter
)
1425 struct trace_seq
*s
= &iter
->seq
;
1426 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1427 struct trace_entry
*entry
;
1428 struct trace_event
*event
;
1432 test_cpu_buff_start(iter
);
1434 event
= ftrace_find_event(entry
->type
);
1436 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1437 if (!trace_print_context(iter
))
1442 return event
->trace(iter
, sym_flags
);
1444 if (!trace_seq_printf(s
, "Unknown type %d\n", entry
->type
))
1447 return TRACE_TYPE_HANDLED
;
1449 return TRACE_TYPE_PARTIAL_LINE
;
1452 static enum print_line_t
print_raw_fmt(struct trace_iterator
*iter
)
1454 struct trace_seq
*s
= &iter
->seq
;
1455 struct trace_entry
*entry
;
1456 struct trace_event
*event
;
1460 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1461 if (!trace_seq_printf(s
, "%d %d %llu ",
1462 entry
->pid
, iter
->cpu
, iter
->ts
))
1466 event
= ftrace_find_event(entry
->type
);
1468 return event
->raw(iter
, 0);
1470 if (!trace_seq_printf(s
, "%d ?\n", entry
->type
))
1473 return TRACE_TYPE_HANDLED
;
1475 return TRACE_TYPE_PARTIAL_LINE
;
1478 static enum print_line_t
print_hex_fmt(struct trace_iterator
*iter
)
1480 struct trace_seq
*s
= &iter
->seq
;
1481 unsigned char newline
= '\n';
1482 struct trace_entry
*entry
;
1483 struct trace_event
*event
;
1487 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1488 SEQ_PUT_HEX_FIELD_RET(s
, entry
->pid
);
1489 SEQ_PUT_HEX_FIELD_RET(s
, iter
->cpu
);
1490 SEQ_PUT_HEX_FIELD_RET(s
, iter
->ts
);
1493 event
= ftrace_find_event(entry
->type
);
1495 enum print_line_t ret
= event
->hex(iter
, 0);
1496 if (ret
!= TRACE_TYPE_HANDLED
)
1500 SEQ_PUT_FIELD_RET(s
, newline
);
1502 return TRACE_TYPE_HANDLED
;
1505 static enum print_line_t
print_printk_msg_only(struct trace_iterator
*iter
)
1507 struct trace_seq
*s
= &iter
->seq
;
1508 struct trace_entry
*entry
= iter
->ent
;
1509 struct print_entry
*field
;
1512 trace_assign_type(field
, entry
);
1514 ret
= trace_seq_printf(s
, "%s", field
->buf
);
1516 return TRACE_TYPE_PARTIAL_LINE
;
1518 return TRACE_TYPE_HANDLED
;
1521 static enum print_line_t
print_bin_fmt(struct trace_iterator
*iter
)
1523 struct trace_seq
*s
= &iter
->seq
;
1524 struct trace_entry
*entry
;
1525 struct trace_event
*event
;
1529 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1530 SEQ_PUT_FIELD_RET(s
, entry
->pid
);
1531 SEQ_PUT_FIELD_RET(s
, iter
->cpu
);
1532 SEQ_PUT_FIELD_RET(s
, iter
->ts
);
1535 event
= ftrace_find_event(entry
->type
);
1536 return event
? event
->binary(iter
, 0) : TRACE_TYPE_HANDLED
;
1539 static int trace_empty(struct trace_iterator
*iter
)
1543 for_each_tracing_cpu(cpu
) {
1544 if (iter
->buffer_iter
[cpu
]) {
1545 if (!ring_buffer_iter_empty(iter
->buffer_iter
[cpu
]))
1548 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
1556 static enum print_line_t
print_trace_line(struct trace_iterator
*iter
)
1558 enum print_line_t ret
;
1560 if (iter
->trace
&& iter
->trace
->print_line
) {
1561 ret
= iter
->trace
->print_line(iter
);
1562 if (ret
!= TRACE_TYPE_UNHANDLED
)
1566 if (iter
->ent
->type
== TRACE_PRINT
&&
1567 trace_flags
& TRACE_ITER_PRINTK
&&
1568 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
1569 return print_printk_msg_only(iter
);
1571 if (trace_flags
& TRACE_ITER_BIN
)
1572 return print_bin_fmt(iter
);
1574 if (trace_flags
& TRACE_ITER_HEX
)
1575 return print_hex_fmt(iter
);
1577 if (trace_flags
& TRACE_ITER_RAW
)
1578 return print_raw_fmt(iter
);
1580 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
)
1581 return print_lat_fmt(iter
);
1583 return print_trace_fmt(iter
);
1586 static int s_show(struct seq_file
*m
, void *v
)
1588 struct trace_iterator
*iter
= v
;
1590 if (iter
->ent
== NULL
) {
1592 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
1595 if (iter
->trace
&& iter
->trace
->print_header
)
1596 iter
->trace
->print_header(m
);
1597 else if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
1598 /* print nothing if the buffers are empty */
1599 if (trace_empty(iter
))
1601 print_trace_header(m
, iter
);
1602 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1603 print_lat_help_header(m
);
1605 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1606 print_func_help_header(m
);
1609 print_trace_line(iter
);
1610 trace_print_seq(m
, &iter
->seq
);
1616 static struct seq_operations tracer_seq_ops
= {
1623 static struct trace_iterator
*
1624 __tracing_open(struct inode
*inode
, struct file
*file
, int *ret
)
1626 struct trace_iterator
*iter
;
1630 if (tracing_disabled
) {
1635 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
1641 mutex_lock(&trace_types_lock
);
1642 if (current_trace
&& current_trace
->print_max
)
1645 iter
->tr
= inode
->i_private
;
1646 iter
->trace
= current_trace
;
1649 /* Notify the tracer early; before we stop tracing. */
1650 if (iter
->trace
&& iter
->trace
->open
)
1651 iter
->trace
->open(iter
);
1653 /* Annotate start of buffers if we had overruns */
1654 if (ring_buffer_overruns(iter
->tr
->buffer
))
1655 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
1658 for_each_tracing_cpu(cpu
) {
1660 iter
->buffer_iter
[cpu
] =
1661 ring_buffer_read_start(iter
->tr
->buffer
, cpu
);
1663 if (!iter
->buffer_iter
[cpu
])
1667 /* TODO stop tracer */
1668 *ret
= seq_open(file
, &tracer_seq_ops
);
1672 m
= file
->private_data
;
1675 /* stop the trace while dumping */
1678 mutex_unlock(&trace_types_lock
);
1684 for_each_tracing_cpu(cpu
) {
1685 if (iter
->buffer_iter
[cpu
])
1686 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
1688 mutex_unlock(&trace_types_lock
);
1691 return ERR_PTR(-ENOMEM
);
1694 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
1696 if (tracing_disabled
)
1699 filp
->private_data
= inode
->i_private
;
1703 int tracing_release(struct inode
*inode
, struct file
*file
)
1705 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
1706 struct trace_iterator
*iter
= m
->private;
1709 mutex_lock(&trace_types_lock
);
1710 for_each_tracing_cpu(cpu
) {
1711 if (iter
->buffer_iter
[cpu
])
1712 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
1715 if (iter
->trace
&& iter
->trace
->close
)
1716 iter
->trace
->close(iter
);
1718 /* reenable tracing if it was previously enabled */
1720 mutex_unlock(&trace_types_lock
);
1722 seq_release(inode
, file
);
1727 static int tracing_open(struct inode
*inode
, struct file
*file
)
1731 __tracing_open(inode
, file
, &ret
);
1736 static int tracing_lt_open(struct inode
*inode
, struct file
*file
)
1738 struct trace_iterator
*iter
;
1741 iter
= __tracing_open(inode
, file
, &ret
);
1744 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
1751 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1753 struct tracer
*t
= m
->private;
1765 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
1767 struct tracer
*t
= m
->private;
1770 mutex_lock(&trace_types_lock
);
1771 for (; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
1777 static void t_stop(struct seq_file
*m
, void *p
)
1779 mutex_unlock(&trace_types_lock
);
1782 static int t_show(struct seq_file
*m
, void *v
)
1784 struct tracer
*t
= v
;
1789 seq_printf(m
, "%s", t
->name
);
1798 static struct seq_operations show_traces_seq_ops
= {
1805 static int show_traces_open(struct inode
*inode
, struct file
*file
)
1809 if (tracing_disabled
)
1812 ret
= seq_open(file
, &show_traces_seq_ops
);
1814 struct seq_file
*m
= file
->private_data
;
1815 m
->private = trace_types
;
1821 static struct file_operations tracing_fops
= {
1822 .open
= tracing_open
,
1824 .llseek
= seq_lseek
,
1825 .release
= tracing_release
,
1828 static struct file_operations tracing_lt_fops
= {
1829 .open
= tracing_lt_open
,
1831 .llseek
= seq_lseek
,
1832 .release
= tracing_release
,
1835 static struct file_operations show_traces_fops
= {
1836 .open
= show_traces_open
,
1838 .release
= seq_release
,
1842 * Only trace on a CPU if the bitmask is set:
1844 static cpumask_var_t tracing_cpumask
;
1847 * The tracer itself will not take this lock, but still we want
1848 * to provide a consistent cpumask to user-space:
1850 static DEFINE_MUTEX(tracing_cpumask_update_lock
);
1853 * Temporary storage for the character representation of the
1854 * CPU bitmask (and one more byte for the newline):
1856 static char mask_str
[NR_CPUS
+ 1];
1859 tracing_cpumask_read(struct file
*filp
, char __user
*ubuf
,
1860 size_t count
, loff_t
*ppos
)
1864 mutex_lock(&tracing_cpumask_update_lock
);
1866 len
= cpumask_scnprintf(mask_str
, count
, tracing_cpumask
);
1867 if (count
- len
< 2) {
1871 len
+= sprintf(mask_str
+ len
, "\n");
1872 count
= simple_read_from_buffer(ubuf
, count
, ppos
, mask_str
, NR_CPUS
+1);
1875 mutex_unlock(&tracing_cpumask_update_lock
);
1881 tracing_cpumask_write(struct file
*filp
, const char __user
*ubuf
,
1882 size_t count
, loff_t
*ppos
)
1885 cpumask_var_t tracing_cpumask_new
;
1887 if (!alloc_cpumask_var(&tracing_cpumask_new
, GFP_KERNEL
))
1890 mutex_lock(&tracing_cpumask_update_lock
);
1891 err
= cpumask_parse_user(ubuf
, count
, tracing_cpumask_new
);
1895 local_irq_disable();
1896 __raw_spin_lock(&ftrace_max_lock
);
1897 for_each_tracing_cpu(cpu
) {
1899 * Increase/decrease the disabled counter if we are
1900 * about to flip a bit in the cpumask:
1902 if (cpumask_test_cpu(cpu
, tracing_cpumask
) &&
1903 !cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
1904 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
1906 if (!cpumask_test_cpu(cpu
, tracing_cpumask
) &&
1907 cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
1908 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
1911 __raw_spin_unlock(&ftrace_max_lock
);
1914 cpumask_copy(tracing_cpumask
, tracing_cpumask_new
);
1916 mutex_unlock(&tracing_cpumask_update_lock
);
1917 free_cpumask_var(tracing_cpumask_new
);
1922 mutex_unlock(&tracing_cpumask_update_lock
);
1923 free_cpumask_var(tracing_cpumask
);
1928 static struct file_operations tracing_cpumask_fops
= {
1929 .open
= tracing_open_generic
,
1930 .read
= tracing_cpumask_read
,
1931 .write
= tracing_cpumask_write
,
1935 tracing_trace_options_read(struct file
*filp
, char __user
*ubuf
,
1936 size_t cnt
, loff_t
*ppos
)
1942 u32 tracer_flags
= current_trace
->flags
->val
;
1943 struct tracer_opt
*trace_opts
= current_trace
->flags
->opts
;
1946 /* calulate max size */
1947 for (i
= 0; trace_options
[i
]; i
++) {
1948 len
+= strlen(trace_options
[i
]);
1949 len
+= 3; /* "no" and space */
1953 * Increase the size with names of options specific
1954 * of the current tracer.
1956 for (i
= 0; trace_opts
[i
].name
; i
++) {
1957 len
+= strlen(trace_opts
[i
].name
);
1958 len
+= 3; /* "no" and space */
1961 /* +2 for \n and \0 */
1962 buf
= kmalloc(len
+ 2, GFP_KERNEL
);
1966 for (i
= 0; trace_options
[i
]; i
++) {
1967 if (trace_flags
& (1 << i
))
1968 r
+= sprintf(buf
+ r
, "%s ", trace_options
[i
]);
1970 r
+= sprintf(buf
+ r
, "no%s ", trace_options
[i
]);
1973 for (i
= 0; trace_opts
[i
].name
; i
++) {
1974 if (tracer_flags
& trace_opts
[i
].bit
)
1975 r
+= sprintf(buf
+ r
, "%s ",
1976 trace_opts
[i
].name
);
1978 r
+= sprintf(buf
+ r
, "no%s ",
1979 trace_opts
[i
].name
);
1982 r
+= sprintf(buf
+ r
, "\n");
1983 WARN_ON(r
>= len
+ 2);
1985 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
1992 /* Try to assign a tracer specific option */
1993 static int set_tracer_option(struct tracer
*trace
, char *cmp
, int neg
)
1995 struct tracer_flags
*trace_flags
= trace
->flags
;
1996 struct tracer_opt
*opts
= NULL
;
2000 for (i
= 0; trace_flags
->opts
[i
].name
; i
++) {
2001 opts
= &trace_flags
->opts
[i
];
2002 len
= strlen(opts
->name
);
2004 if (strncmp(cmp
, opts
->name
, len
) == 0) {
2005 ret
= trace
->set_flag(trace_flags
->val
,
2011 if (!trace_flags
->opts
[i
].name
)
2014 /* Refused to handle */
2019 trace_flags
->val
&= ~opts
->bit
;
2021 trace_flags
->val
|= opts
->bit
;
2027 tracing_trace_options_write(struct file
*filp
, const char __user
*ubuf
,
2028 size_t cnt
, loff_t
*ppos
)
2036 if (cnt
>= sizeof(buf
))
2039 if (copy_from_user(&buf
, ubuf
, cnt
))
2044 if (strncmp(buf
, "no", 2) == 0) {
2049 for (i
= 0; trace_options
[i
]; i
++) {
2050 int len
= strlen(trace_options
[i
]);
2052 if (strncmp(cmp
, trace_options
[i
], len
) == 0) {
2054 trace_flags
&= ~(1 << i
);
2056 trace_flags
|= (1 << i
);
2061 /* If no option could be set, test the specific tracer options */
2062 if (!trace_options
[i
]) {
2063 ret
= set_tracer_option(current_trace
, cmp
, neg
);
2073 static struct file_operations tracing_iter_fops
= {
2074 .open
= tracing_open_generic
,
2075 .read
= tracing_trace_options_read
,
2076 .write
= tracing_trace_options_write
,
2079 static const char readme_msg
[] =
2080 "tracing mini-HOWTO:\n\n"
2082 "# mount -t debugfs nodev /debug\n\n"
2083 "# cat /debug/tracing/available_tracers\n"
2084 "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
2085 "# cat /debug/tracing/current_tracer\n"
2087 "# echo sched_switch > /debug/tracing/current_tracer\n"
2088 "# cat /debug/tracing/current_tracer\n"
2090 "# cat /debug/tracing/trace_options\n"
2091 "noprint-parent nosym-offset nosym-addr noverbose\n"
2092 "# echo print-parent > /debug/tracing/trace_options\n"
2093 "# echo 1 > /debug/tracing/tracing_enabled\n"
2094 "# cat /debug/tracing/trace > /tmp/trace.txt\n"
2095 "echo 0 > /debug/tracing/tracing_enabled\n"
2099 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
2100 size_t cnt
, loff_t
*ppos
)
2102 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
2103 readme_msg
, strlen(readme_msg
));
2106 static struct file_operations tracing_readme_fops
= {
2107 .open
= tracing_open_generic
,
2108 .read
= tracing_readme_read
,
2112 tracing_ctrl_read(struct file
*filp
, char __user
*ubuf
,
2113 size_t cnt
, loff_t
*ppos
)
2118 r
= sprintf(buf
, "%u\n", tracer_enabled
);
2119 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2123 tracing_ctrl_write(struct file
*filp
, const char __user
*ubuf
,
2124 size_t cnt
, loff_t
*ppos
)
2126 struct trace_array
*tr
= filp
->private_data
;
2131 if (cnt
>= sizeof(buf
))
2134 if (copy_from_user(&buf
, ubuf
, cnt
))
2139 ret
= strict_strtoul(buf
, 10, &val
);
2145 mutex_lock(&trace_types_lock
);
2146 if (tracer_enabled
^ val
) {
2149 if (current_trace
->start
)
2150 current_trace
->start(tr
);
2155 if (current_trace
->stop
)
2156 current_trace
->stop(tr
);
2159 mutex_unlock(&trace_types_lock
);
2167 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
2168 size_t cnt
, loff_t
*ppos
)
2170 char buf
[max_tracer_type_len
+2];
2173 mutex_lock(&trace_types_lock
);
2175 r
= sprintf(buf
, "%s\n", current_trace
->name
);
2177 r
= sprintf(buf
, "\n");
2178 mutex_unlock(&trace_types_lock
);
2180 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2183 int tracer_init(struct tracer
*t
, struct trace_array
*tr
)
2185 tracing_reset_online_cpus(tr
);
2189 static int tracing_set_tracer(const char *buf
)
2191 struct trace_array
*tr
= &global_trace
;
2195 mutex_lock(&trace_types_lock
);
2196 for (t
= trace_types
; t
; t
= t
->next
) {
2197 if (strcmp(t
->name
, buf
) == 0)
2204 if (t
== current_trace
)
2207 trace_branch_disable();
2208 if (current_trace
&& current_trace
->reset
)
2209 current_trace
->reset(tr
);
2213 ret
= tracer_init(t
, tr
);
2218 trace_branch_enable(tr
);
2220 mutex_unlock(&trace_types_lock
);
2226 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
2227 size_t cnt
, loff_t
*ppos
)
2229 char buf
[max_tracer_type_len
+1];
2236 if (cnt
> max_tracer_type_len
)
2237 cnt
= max_tracer_type_len
;
2239 if (copy_from_user(&buf
, ubuf
, cnt
))
2244 /* strip ending whitespace. */
2245 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
2248 err
= tracing_set_tracer(buf
);
2258 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
2259 size_t cnt
, loff_t
*ppos
)
2261 unsigned long *ptr
= filp
->private_data
;
2265 r
= snprintf(buf
, sizeof(buf
), "%ld\n",
2266 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
2267 if (r
> sizeof(buf
))
2269 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2273 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
2274 size_t cnt
, loff_t
*ppos
)
2276 long *ptr
= filp
->private_data
;
2281 if (cnt
>= sizeof(buf
))
2284 if (copy_from_user(&buf
, ubuf
, cnt
))
2289 ret
= strict_strtoul(buf
, 10, &val
);
2298 static atomic_t tracing_reader
;
2300 static int tracing_open_pipe(struct inode
*inode
, struct file
*filp
)
2302 struct trace_iterator
*iter
;
2304 if (tracing_disabled
)
2307 /* We only allow for reader of the pipe */
2308 if (atomic_inc_return(&tracing_reader
) != 1) {
2309 atomic_dec(&tracing_reader
);
2313 /* create a buffer to store the information to pass to userspace */
2314 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2318 if (!alloc_cpumask_var(&iter
->started
, GFP_KERNEL
)) {
2323 mutex_lock(&trace_types_lock
);
2325 /* trace pipe does not show start of buffer */
2326 cpumask_setall(iter
->started
);
2328 iter
->tr
= &global_trace
;
2329 iter
->trace
= current_trace
;
2330 filp
->private_data
= iter
;
2332 if (iter
->trace
->pipe_open
)
2333 iter
->trace
->pipe_open(iter
);
2334 mutex_unlock(&trace_types_lock
);
2339 static int tracing_release_pipe(struct inode
*inode
, struct file
*file
)
2341 struct trace_iterator
*iter
= file
->private_data
;
2343 free_cpumask_var(iter
->started
);
2345 atomic_dec(&tracing_reader
);
2351 tracing_poll_pipe(struct file
*filp
, poll_table
*poll_table
)
2353 struct trace_iterator
*iter
= filp
->private_data
;
2355 if (trace_flags
& TRACE_ITER_BLOCK
) {
2357 * Always select as readable when in blocking mode
2359 return POLLIN
| POLLRDNORM
;
2361 if (!trace_empty(iter
))
2362 return POLLIN
| POLLRDNORM
;
2363 poll_wait(filp
, &trace_wait
, poll_table
);
2364 if (!trace_empty(iter
))
2365 return POLLIN
| POLLRDNORM
;
2375 tracing_read_pipe(struct file
*filp
, char __user
*ubuf
,
2376 size_t cnt
, loff_t
*ppos
)
2378 struct trace_iterator
*iter
= filp
->private_data
;
2381 /* return any leftover data */
2382 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
2386 trace_seq_reset(&iter
->seq
);
2388 mutex_lock(&trace_types_lock
);
2389 if (iter
->trace
->read
) {
2390 sret
= iter
->trace
->read(iter
, filp
, ubuf
, cnt
, ppos
);
2397 while (trace_empty(iter
)) {
2399 if ((filp
->f_flags
& O_NONBLOCK
)) {
2405 * This is a make-shift waitqueue. The reason we don't use
2406 * an actual wait queue is because:
2407 * 1) we only ever have one waiter
2408 * 2) the tracing, traces all functions, we don't want
2409 * the overhead of calling wake_up and friends
2410 * (and tracing them too)
2411 * Anyway, this is really very primitive wakeup.
2413 set_current_state(TASK_INTERRUPTIBLE
);
2414 iter
->tr
->waiter
= current
;
2416 mutex_unlock(&trace_types_lock
);
2418 /* sleep for 100 msecs, and try again. */
2419 schedule_timeout(HZ
/10);
2421 mutex_lock(&trace_types_lock
);
2423 iter
->tr
->waiter
= NULL
;
2425 if (signal_pending(current
)) {
2430 if (iter
->trace
!= current_trace
)
2434 * We block until we read something and tracing is disabled.
2435 * We still block if tracing is disabled, but we have never
2436 * read anything. This allows a user to cat this file, and
2437 * then enable tracing. But after we have read something,
2438 * we give an EOF when tracing is again disabled.
2440 * iter->pos will be 0 if we haven't read anything.
2442 if (!tracer_enabled
&& iter
->pos
)
2448 /* stop when tracing is finished */
2449 if (trace_empty(iter
))
2452 if (cnt
>= PAGE_SIZE
)
2453 cnt
= PAGE_SIZE
- 1;
2455 /* reset all but tr, trace, and overruns */
2456 memset(&iter
->seq
, 0,
2457 sizeof(struct trace_iterator
) -
2458 offsetof(struct trace_iterator
, seq
));
2461 while (find_next_entry_inc(iter
) != NULL
) {
2462 enum print_line_t ret
;
2463 int len
= iter
->seq
.len
;
2465 ret
= print_trace_line(iter
);
2466 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
2467 /* don't print partial lines */
2468 iter
->seq
.len
= len
;
2472 trace_consume(iter
);
2474 if (iter
->seq
.len
>= cnt
)
2478 /* Now copy what we have to the user */
2479 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
2480 if (iter
->seq
.readpos
>= iter
->seq
.len
)
2481 trace_seq_reset(&iter
->seq
);
2484 * If there was nothing to send to user, inspite of consuming trace
2485 * entries, go back to wait for more entries.
2491 mutex_unlock(&trace_types_lock
);
2497 tracing_entries_read(struct file
*filp
, char __user
*ubuf
,
2498 size_t cnt
, loff_t
*ppos
)
2500 struct trace_array
*tr
= filp
->private_data
;
2504 r
= sprintf(buf
, "%lu\n", tr
->entries
>> 10);
2505 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2509 tracing_entries_write(struct file
*filp
, const char __user
*ubuf
,
2510 size_t cnt
, loff_t
*ppos
)
2516 if (cnt
>= sizeof(buf
))
2519 if (copy_from_user(&buf
, ubuf
, cnt
))
2524 ret
= strict_strtoul(buf
, 10, &val
);
2528 /* must have at least 1 entry */
2532 mutex_lock(&trace_types_lock
);
2536 /* disable all cpu buffers */
2537 for_each_tracing_cpu(cpu
) {
2538 if (global_trace
.data
[cpu
])
2539 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
2540 if (max_tr
.data
[cpu
])
2541 atomic_inc(&max_tr
.data
[cpu
]->disabled
);
2544 /* value is in KB */
2547 if (val
!= global_trace
.entries
) {
2548 ret
= ring_buffer_resize(global_trace
.buffer
, val
);
2554 ret
= ring_buffer_resize(max_tr
.buffer
, val
);
2558 r
= ring_buffer_resize(global_trace
.buffer
,
2559 global_trace
.entries
);
2561 /* AARGH! We are left with different
2562 * size max buffer!!!! */
2564 tracing_disabled
= 1;
2569 global_trace
.entries
= val
;
2574 /* If check pages failed, return ENOMEM */
2575 if (tracing_disabled
)
2578 for_each_tracing_cpu(cpu
) {
2579 if (global_trace
.data
[cpu
])
2580 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
2581 if (max_tr
.data
[cpu
])
2582 atomic_dec(&max_tr
.data
[cpu
]->disabled
);
2586 max_tr
.entries
= global_trace
.entries
;
2587 mutex_unlock(&trace_types_lock
);
2592 static int mark_printk(const char *fmt
, ...)
2596 va_start(args
, fmt
);
2597 ret
= trace_vprintk(0, -1, fmt
, args
);
2603 tracing_mark_write(struct file
*filp
, const char __user
*ubuf
,
2604 size_t cnt
, loff_t
*fpos
)
2609 if (tracing_disabled
)
2612 if (cnt
> TRACE_BUF_SIZE
)
2613 cnt
= TRACE_BUF_SIZE
;
2615 buf
= kmalloc(cnt
+ 1, GFP_KERNEL
);
2619 if (copy_from_user(buf
, ubuf
, cnt
)) {
2624 /* Cut from the first nil or newline. */
2626 end
= strchr(buf
, '\n');
2630 cnt
= mark_printk("%s\n", buf
);
2637 static struct file_operations tracing_max_lat_fops
= {
2638 .open
= tracing_open_generic
,
2639 .read
= tracing_max_lat_read
,
2640 .write
= tracing_max_lat_write
,
2643 static struct file_operations tracing_ctrl_fops
= {
2644 .open
= tracing_open_generic
,
2645 .read
= tracing_ctrl_read
,
2646 .write
= tracing_ctrl_write
,
2649 static struct file_operations set_tracer_fops
= {
2650 .open
= tracing_open_generic
,
2651 .read
= tracing_set_trace_read
,
2652 .write
= tracing_set_trace_write
,
2655 static struct file_operations tracing_pipe_fops
= {
2656 .open
= tracing_open_pipe
,
2657 .poll
= tracing_poll_pipe
,
2658 .read
= tracing_read_pipe
,
2659 .release
= tracing_release_pipe
,
2662 static struct file_operations tracing_entries_fops
= {
2663 .open
= tracing_open_generic
,
2664 .read
= tracing_entries_read
,
2665 .write
= tracing_entries_write
,
2668 static struct file_operations tracing_mark_fops
= {
2669 .open
= tracing_open_generic
,
2670 .write
= tracing_mark_write
,
2673 #ifdef CONFIG_DYNAMIC_FTRACE
2675 int __weak
ftrace_arch_read_dyn_info(char *buf
, int size
)
2681 tracing_read_dyn_info(struct file
*filp
, char __user
*ubuf
,
2682 size_t cnt
, loff_t
*ppos
)
2684 static char ftrace_dyn_info_buffer
[1024];
2685 static DEFINE_MUTEX(dyn_info_mutex
);
2686 unsigned long *p
= filp
->private_data
;
2687 char *buf
= ftrace_dyn_info_buffer
;
2688 int size
= ARRAY_SIZE(ftrace_dyn_info_buffer
);
2691 mutex_lock(&dyn_info_mutex
);
2692 r
= sprintf(buf
, "%ld ", *p
);
2694 r
+= ftrace_arch_read_dyn_info(buf
+r
, (size
-1)-r
);
2697 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2699 mutex_unlock(&dyn_info_mutex
);
2704 static struct file_operations tracing_dyn_info_fops
= {
2705 .open
= tracing_open_generic
,
2706 .read
= tracing_read_dyn_info
,
2710 static struct dentry
*d_tracer
;
2712 struct dentry
*tracing_init_dentry(void)
2719 d_tracer
= debugfs_create_dir("tracing", NULL
);
2721 if (!d_tracer
&& !once
) {
2723 pr_warning("Could not create debugfs directory 'tracing'\n");
2730 #ifdef CONFIG_FTRACE_SELFTEST
2731 /* Let selftest have access to static functions in this file */
2732 #include "trace_selftest.c"
2735 static __init
int tracer_init_debugfs(void)
2737 struct dentry
*d_tracer
;
2738 struct dentry
*entry
;
2740 d_tracer
= tracing_init_dentry();
2742 entry
= debugfs_create_file("tracing_enabled", 0644, d_tracer
,
2743 &global_trace
, &tracing_ctrl_fops
);
2745 pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
2747 entry
= debugfs_create_file("trace_options", 0644, d_tracer
,
2748 NULL
, &tracing_iter_fops
);
2750 pr_warning("Could not create debugfs 'trace_options' entry\n");
2752 entry
= debugfs_create_file("tracing_cpumask", 0644, d_tracer
,
2753 NULL
, &tracing_cpumask_fops
);
2755 pr_warning("Could not create debugfs 'tracing_cpumask' entry\n");
2757 entry
= debugfs_create_file("latency_trace", 0444, d_tracer
,
2758 &global_trace
, &tracing_lt_fops
);
2760 pr_warning("Could not create debugfs 'latency_trace' entry\n");
2762 entry
= debugfs_create_file("trace", 0444, d_tracer
,
2763 &global_trace
, &tracing_fops
);
2765 pr_warning("Could not create debugfs 'trace' entry\n");
2767 entry
= debugfs_create_file("available_tracers", 0444, d_tracer
,
2768 &global_trace
, &show_traces_fops
);
2770 pr_warning("Could not create debugfs 'available_tracers' entry\n");
2772 entry
= debugfs_create_file("current_tracer", 0444, d_tracer
,
2773 &global_trace
, &set_tracer_fops
);
2775 pr_warning("Could not create debugfs 'current_tracer' entry\n");
2777 entry
= debugfs_create_file("tracing_max_latency", 0644, d_tracer
,
2778 &tracing_max_latency
,
2779 &tracing_max_lat_fops
);
2781 pr_warning("Could not create debugfs "
2782 "'tracing_max_latency' entry\n");
2784 entry
= debugfs_create_file("tracing_thresh", 0644, d_tracer
,
2785 &tracing_thresh
, &tracing_max_lat_fops
);
2787 pr_warning("Could not create debugfs "
2788 "'tracing_thresh' entry\n");
2789 entry
= debugfs_create_file("README", 0644, d_tracer
,
2790 NULL
, &tracing_readme_fops
);
2792 pr_warning("Could not create debugfs 'README' entry\n");
2794 entry
= debugfs_create_file("trace_pipe", 0644, d_tracer
,
2795 NULL
, &tracing_pipe_fops
);
2797 pr_warning("Could not create debugfs "
2798 "'trace_pipe' entry\n");
2800 entry
= debugfs_create_file("buffer_size_kb", 0644, d_tracer
,
2801 &global_trace
, &tracing_entries_fops
);
2803 pr_warning("Could not create debugfs "
2804 "'buffer_size_kb' entry\n");
2806 entry
= debugfs_create_file("trace_marker", 0220, d_tracer
,
2807 NULL
, &tracing_mark_fops
);
2809 pr_warning("Could not create debugfs "
2810 "'trace_marker' entry\n");
2812 #ifdef CONFIG_DYNAMIC_FTRACE
2813 entry
= debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
2814 &ftrace_update_tot_cnt
,
2815 &tracing_dyn_info_fops
);
2817 pr_warning("Could not create debugfs "
2818 "'dyn_ftrace_total_info' entry\n");
2820 #ifdef CONFIG_SYSPROF_TRACER
2821 init_tracer_sysprof_debugfs(d_tracer
);
2826 int trace_vprintk(unsigned long ip
, int depth
, const char *fmt
, va_list args
)
2828 static DEFINE_SPINLOCK(trace_buf_lock
);
2829 static char trace_buf
[TRACE_BUF_SIZE
];
2831 struct ring_buffer_event
*event
;
2832 struct trace_array
*tr
= &global_trace
;
2833 struct trace_array_cpu
*data
;
2834 int cpu
, len
= 0, size
, pc
;
2835 struct print_entry
*entry
;
2836 unsigned long irq_flags
;
2838 if (tracing_disabled
|| tracing_selftest_running
)
2841 pc
= preempt_count();
2842 preempt_disable_notrace();
2843 cpu
= raw_smp_processor_id();
2844 data
= tr
->data
[cpu
];
2846 if (unlikely(atomic_read(&data
->disabled
)))
2849 pause_graph_tracing();
2850 spin_lock_irqsave(&trace_buf_lock
, irq_flags
);
2851 len
= vsnprintf(trace_buf
, TRACE_BUF_SIZE
, fmt
, args
);
2853 len
= min(len
, TRACE_BUF_SIZE
-1);
2856 size
= sizeof(*entry
) + len
+ 1;
2857 event
= trace_buffer_lock_reserve(tr
, TRACE_PRINT
, size
, irq_flags
, pc
);
2860 entry
= ring_buffer_event_data(event
);
2862 entry
->depth
= depth
;
2864 memcpy(&entry
->buf
, trace_buf
, len
);
2865 entry
->buf
[len
] = 0;
2866 ring_buffer_unlock_commit(tr
->buffer
, event
);
2869 spin_unlock_irqrestore(&trace_buf_lock
, irq_flags
);
2870 unpause_graph_tracing();
2872 preempt_enable_notrace();
2876 EXPORT_SYMBOL_GPL(trace_vprintk
);
2878 int __ftrace_printk(unsigned long ip
, const char *fmt
, ...)
2883 if (!(trace_flags
& TRACE_ITER_PRINTK
))
2887 ret
= trace_vprintk(ip
, task_curr_ret_stack(current
), fmt
, ap
);
2891 EXPORT_SYMBOL_GPL(__ftrace_printk
);
2893 int __ftrace_vprintk(unsigned long ip
, const char *fmt
, va_list ap
)
2895 if (!(trace_flags
& TRACE_ITER_PRINTK
))
2898 return trace_vprintk(ip
, task_curr_ret_stack(current
), fmt
, ap
);
2900 EXPORT_SYMBOL_GPL(__ftrace_vprintk
);
2902 static int trace_panic_handler(struct notifier_block
*this,
2903 unsigned long event
, void *unused
)
2905 if (ftrace_dump_on_oops
)
2910 static struct notifier_block trace_panic_notifier
= {
2911 .notifier_call
= trace_panic_handler
,
2913 .priority
= 150 /* priority: INT_MAX >= x >= 0 */
2916 static int trace_die_handler(struct notifier_block
*self
,
2922 if (ftrace_dump_on_oops
)
2931 static struct notifier_block trace_die_notifier
= {
2932 .notifier_call
= trace_die_handler
,
2937 * printk is set to max of 1024, we really don't need it that big.
2938 * Nothing should be printing 1000 characters anyway.
2940 #define TRACE_MAX_PRINT 1000
2943 * Define here KERN_TRACE so that we have one place to modify
2944 * it if we decide to change what log level the ftrace dump
2947 #define KERN_TRACE KERN_EMERG
2950 trace_printk_seq(struct trace_seq
*s
)
2952 /* Probably should print a warning here. */
2956 /* should be zero ended, but we are paranoid. */
2957 s
->buffer
[s
->len
] = 0;
2959 printk(KERN_TRACE
"%s", s
->buffer
);
2964 void ftrace_dump(void)
2966 static DEFINE_SPINLOCK(ftrace_dump_lock
);
2967 /* use static because iter can be a bit big for the stack */
2968 static struct trace_iterator iter
;
2969 static int dump_ran
;
2970 unsigned long flags
;
2974 spin_lock_irqsave(&ftrace_dump_lock
, flags
);
2980 /* No turning back! */
2984 for_each_tracing_cpu(cpu
) {
2985 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
2988 /* don't look at user memory in panic mode */
2989 trace_flags
&= ~TRACE_ITER_SYM_USEROBJ
;
2991 printk(KERN_TRACE
"Dumping ftrace buffer:\n");
2993 iter
.tr
= &global_trace
;
2994 iter
.trace
= current_trace
;
2997 * We need to stop all tracing on all CPUS to read the
2998 * the next buffer. This is a bit expensive, but is
2999 * not done often. We fill all what we can read,
3000 * and then release the locks again.
3003 while (!trace_empty(&iter
)) {
3006 printk(KERN_TRACE
"---------------------------------\n");
3010 /* reset all but tr, trace, and overruns */
3011 memset(&iter
.seq
, 0,
3012 sizeof(struct trace_iterator
) -
3013 offsetof(struct trace_iterator
, seq
));
3014 iter
.iter_flags
|= TRACE_FILE_LAT_FMT
;
3017 if (find_next_entry_inc(&iter
) != NULL
) {
3018 print_trace_line(&iter
);
3019 trace_consume(&iter
);
3022 trace_printk_seq(&iter
.seq
);
3026 printk(KERN_TRACE
" (ftrace buffer empty)\n");
3028 printk(KERN_TRACE
"---------------------------------\n");
3031 spin_unlock_irqrestore(&ftrace_dump_lock
, flags
);
3034 __init
static int tracer_alloc_buffers(void)
3036 struct trace_array_cpu
*data
;
3040 if (!alloc_cpumask_var(&tracing_buffer_mask
, GFP_KERNEL
))
3043 if (!alloc_cpumask_var(&tracing_cpumask
, GFP_KERNEL
))
3044 goto out_free_buffer_mask
;
3046 cpumask_copy(tracing_buffer_mask
, cpu_possible_mask
);
3047 cpumask_copy(tracing_cpumask
, cpu_all_mask
);
3049 /* TODO: make the number of buffers hot pluggable with CPUS */
3050 global_trace
.buffer
= ring_buffer_alloc(trace_buf_size
,
3051 TRACE_BUFFER_FLAGS
);
3052 if (!global_trace
.buffer
) {
3053 printk(KERN_ERR
"tracer: failed to allocate ring buffer!\n");
3055 goto out_free_cpumask
;
3057 global_trace
.entries
= ring_buffer_size(global_trace
.buffer
);
3060 #ifdef CONFIG_TRACER_MAX_TRACE
3061 max_tr
.buffer
= ring_buffer_alloc(trace_buf_size
,
3062 TRACE_BUFFER_FLAGS
);
3063 if (!max_tr
.buffer
) {
3064 printk(KERN_ERR
"tracer: failed to allocate max ring buffer!\n");
3066 ring_buffer_free(global_trace
.buffer
);
3067 goto out_free_cpumask
;
3069 max_tr
.entries
= ring_buffer_size(max_tr
.buffer
);
3070 WARN_ON(max_tr
.entries
!= global_trace
.entries
);
3073 /* Allocate the first page for all buffers */
3074 for_each_tracing_cpu(i
) {
3075 data
= global_trace
.data
[i
] = &per_cpu(global_trace_cpu
, i
);
3076 max_tr
.data
[i
] = &per_cpu(max_data
, i
);
3079 trace_init_cmdlines();
3081 register_tracer(&nop_trace
);
3082 current_trace
= &nop_trace
;
3083 #ifdef CONFIG_BOOT_TRACER
3084 register_tracer(&boot_tracer
);
3086 /* All seems OK, enable tracing */
3087 tracing_disabled
= 0;
3089 atomic_notifier_chain_register(&panic_notifier_list
,
3090 &trace_panic_notifier
);
3092 register_die_notifier(&trace_die_notifier
);
3096 free_cpumask_var(tracing_cpumask
);
3097 out_free_buffer_mask
:
3098 free_cpumask_var(tracing_buffer_mask
);
3103 __init
static int clear_boot_tracer(void)
3106 * The default tracer at boot buffer is an init section.
3107 * This function is called in lateinit. If we did not
3108 * find the boot tracer, then clear it out, to prevent
3109 * later registration from accessing the buffer that is
3110 * about to be freed.
3112 if (!default_bootup_tracer
)
3115 printk(KERN_INFO
"ftrace bootup tracer '%s' not registered.\n",
3116 default_bootup_tracer
);
3117 default_bootup_tracer
= NULL
;
3122 early_initcall(tracer_alloc_buffers
);
3123 fs_initcall(tracer_init_debugfs
);
3124 late_initcall(clear_boot_tracer
);