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 * 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 static 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 which cpu buffers are currently read in trace_pipe */
101 static cpumask_var_t tracing_reader_cpumask
;
103 #define for_each_tracing_cpu(cpu) \
104 for_each_cpu(cpu, tracing_buffer_mask)
107 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
109 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
110 * is set, then ftrace_dump is called. This will output the contents
111 * of the ftrace buffers to the console. This is very useful for
112 * capturing traces that lead to crashes and outputing it to a
115 * It is default off, but you can enable it with either specifying
116 * "ftrace_dump_on_oops" in the kernel command line, or setting
117 * /proc/sys/kernel/ftrace_dump_on_oops to true.
119 int ftrace_dump_on_oops
;
121 static int tracing_set_tracer(const char *buf
);
123 #define BOOTUP_TRACER_SIZE 100
124 static char bootup_tracer_buf
[BOOTUP_TRACER_SIZE
] __initdata
;
125 static char *default_bootup_tracer
;
127 static int __init
set_ftrace(char *str
)
129 strncpy(bootup_tracer_buf
, str
, BOOTUP_TRACER_SIZE
);
130 default_bootup_tracer
= bootup_tracer_buf
;
133 __setup("ftrace=", set_ftrace
);
135 static int __init
set_ftrace_dump_on_oops(char *str
)
137 ftrace_dump_on_oops
= 1;
140 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops
);
143 ns2usecs(cycle_t nsec
)
150 cycle_t
ftrace_now(int cpu
)
152 u64 ts
= ring_buffer_time_stamp(cpu
);
153 ring_buffer_normalize_time_stamp(cpu
, &ts
);
158 * The global_trace is the descriptor that holds the tracing
159 * buffers for the live tracing. For each CPU, it contains
160 * a link list of pages that will store trace entries. The
161 * page descriptor of the pages in the memory is used to hold
162 * the link list by linking the lru item in the page descriptor
163 * to each of the pages in the buffer per CPU.
165 * For each active CPU there is a data field that holds the
166 * pages for the buffer for that CPU. Each CPU has the same number
167 * of pages allocated for its buffer.
169 static struct trace_array global_trace
;
171 static DEFINE_PER_CPU(struct trace_array_cpu
, global_trace_cpu
);
174 * The max_tr is used to snapshot the global_trace when a maximum
175 * latency is reached. Some tracers will use this to store a maximum
176 * trace while it continues examining live traces.
178 * The buffers for the max_tr are set up the same as the global_trace.
179 * When a snapshot is taken, the link list of the max_tr is swapped
180 * with the link list of the global_trace and the buffers are reset for
181 * the global_trace so the tracing can continue.
183 static struct trace_array max_tr
;
185 static DEFINE_PER_CPU(struct trace_array_cpu
, max_data
);
187 /* tracer_enabled is used to toggle activation of a tracer */
188 static int tracer_enabled
= 1;
191 * tracing_is_enabled - return tracer_enabled status
193 * This function is used by other tracers to know the status
194 * of the tracer_enabled flag. Tracers may use this function
195 * to know if it should enable their features when starting
196 * up. See irqsoff tracer for an example (start_irqsoff_tracer).
198 int tracing_is_enabled(void)
200 return tracer_enabled
;
204 * trace_buf_size is the size in bytes that is allocated
205 * for a buffer. Note, the number of bytes is always rounded
208 * This number is purposely set to a low number of 16384.
209 * If the dump on oops happens, it will be much appreciated
210 * to not have to wait for all that output. Anyway this can be
211 * boot time and run time configurable.
213 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
215 static unsigned long trace_buf_size
= TRACE_BUF_SIZE_DEFAULT
;
217 /* trace_types holds a link list of available tracers. */
218 static struct tracer
*trace_types __read_mostly
;
220 /* current_trace points to the tracer that is currently active */
221 static struct tracer
*current_trace __read_mostly
;
224 * max_tracer_type_len is used to simplify the allocating of
225 * buffers to read userspace tracer names. We keep track of
226 * the longest tracer name registered.
228 static int max_tracer_type_len
;
231 * trace_types_lock is used to protect the trace_types list.
232 * This lock is also used to keep user access serialized.
233 * Accesses from userspace will grab this lock while userspace
234 * activities happen inside the kernel.
236 static DEFINE_MUTEX(trace_types_lock
);
238 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
239 static DECLARE_WAIT_QUEUE_HEAD(trace_wait
);
241 /* trace_flags holds trace_options default values */
242 unsigned long trace_flags
= TRACE_ITER_PRINT_PARENT
| TRACE_ITER_PRINTK
|
243 TRACE_ITER_ANNOTATE
| TRACE_ITER_CONTEXT_INFO
;
246 * trace_wake_up - wake up tasks waiting for trace input
248 * Simply wakes up any task that is blocked on the trace_wait
249 * queue. These is used with trace_poll for tasks polling the trace.
251 void trace_wake_up(void)
254 * The runqueue_is_locked() can fail, but this is the best we
257 if (!(trace_flags
& TRACE_ITER_BLOCK
) && !runqueue_is_locked())
258 wake_up(&trace_wait
);
261 static int __init
set_buf_size(char *str
)
263 unsigned long buf_size
;
268 ret
= strict_strtoul(str
, 0, &buf_size
);
269 /* nr_entries can not be zero */
270 if (ret
< 0 || buf_size
== 0)
272 trace_buf_size
= buf_size
;
275 __setup("trace_buf_size=", set_buf_size
);
277 unsigned long nsecs_to_usecs(unsigned long nsecs
)
282 /* These must match the bit postions in trace_iterator_flags */
283 static const char *trace_options
[] = {
307 * ftrace_max_lock is used to protect the swapping of buffers
308 * when taking a max snapshot. The buffers themselves are
309 * protected by per_cpu spinlocks. But the action of the swap
310 * needs its own lock.
312 * This is defined as a raw_spinlock_t in order to help
313 * with performance when lockdep debugging is enabled.
315 static raw_spinlock_t ftrace_max_lock
=
316 (raw_spinlock_t
)__RAW_SPIN_LOCK_UNLOCKED
;
319 * Copy the new maximum trace into the separate maximum-trace
320 * structure. (this way the maximum trace is permanently saved,
321 * for later retrieval via /debugfs/tracing/latency_trace)
324 __update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
326 struct trace_array_cpu
*data
= tr
->data
[cpu
];
329 max_tr
.time_start
= data
->preempt_timestamp
;
331 data
= max_tr
.data
[cpu
];
332 data
->saved_latency
= tracing_max_latency
;
334 memcpy(data
->comm
, tsk
->comm
, TASK_COMM_LEN
);
335 data
->pid
= tsk
->pid
;
336 data
->uid
= task_uid(tsk
);
337 data
->nice
= tsk
->static_prio
- 20 - MAX_RT_PRIO
;
338 data
->policy
= tsk
->policy
;
339 data
->rt_priority
= tsk
->rt_priority
;
341 /* record this tasks comm */
342 tracing_record_cmdline(tsk
);
345 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
);
369 ssize_t
trace_seq_to_buffer(struct trace_seq
*s
, void *buf
, size_t cnt
)
374 if (s
->len
<= s
->readpos
)
377 len
= s
->len
- s
->readpos
;
380 ret
= memcpy(buf
, s
->buffer
+ s
->readpos
, cnt
);
389 trace_print_seq(struct seq_file
*m
, struct trace_seq
*s
)
391 int len
= s
->len
>= PAGE_SIZE
? PAGE_SIZE
- 1 : s
->len
;
394 seq_puts(m
, s
->buffer
);
400 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
402 * @tsk: the task with the latency
403 * @cpu: The cpu that initiated the trace.
405 * Flip the buffers between the @tr and the max_tr and record information
406 * about which task was the cause of this latency.
409 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
411 struct ring_buffer
*buf
= tr
->buffer
;
413 WARN_ON_ONCE(!irqs_disabled());
414 __raw_spin_lock(&ftrace_max_lock
);
416 tr
->buffer
= max_tr
.buffer
;
419 ftrace_disable_cpu();
420 ring_buffer_reset(tr
->buffer
);
423 __update_max_tr(tr
, tsk
, cpu
);
424 __raw_spin_unlock(&ftrace_max_lock
);
428 * update_max_tr_single - only copy one trace over, and reset the rest
430 * @tsk - task with the latency
431 * @cpu - the cpu of the buffer to copy.
433 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
436 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
440 WARN_ON_ONCE(!irqs_disabled());
441 __raw_spin_lock(&ftrace_max_lock
);
443 ftrace_disable_cpu();
445 ring_buffer_reset(max_tr
.buffer
);
446 ret
= ring_buffer_swap_cpu(max_tr
.buffer
, tr
->buffer
, cpu
);
450 WARN_ON_ONCE(ret
&& ret
!= -EAGAIN
);
452 __update_max_tr(tr
, tsk
, cpu
);
453 __raw_spin_unlock(&ftrace_max_lock
);
457 * register_tracer - register a tracer with the ftrace system.
458 * @type - the plugin for the tracer
460 * Register a new plugin tracer.
462 int register_tracer(struct tracer
*type
)
463 __releases(kernel_lock
)
464 __acquires(kernel_lock
)
471 pr_info("Tracer must have a name\n");
476 * When this gets called we hold the BKL which means that
477 * preemption is disabled. Various trace selftests however
478 * need to disable and enable preemption for successful tests.
479 * So we drop the BKL here and grab it after the tests again.
482 mutex_lock(&trace_types_lock
);
484 tracing_selftest_running
= true;
486 for (t
= trace_types
; t
; t
= t
->next
) {
487 if (strcmp(type
->name
, t
->name
) == 0) {
489 pr_info("Trace %s already registered\n",
497 type
->set_flag
= &dummy_set_flag
;
499 type
->flags
= &dummy_tracer_flags
;
501 if (!type
->flags
->opts
)
502 type
->flags
->opts
= dummy_tracer_opt
;
503 if (!type
->wait_pipe
)
504 type
->wait_pipe
= default_wait_pipe
;
507 #ifdef CONFIG_FTRACE_STARTUP_TEST
508 if (type
->selftest
&& !tracing_selftest_disabled
) {
509 struct tracer
*saved_tracer
= current_trace
;
510 struct trace_array
*tr
= &global_trace
;
514 * Run a selftest on this tracer.
515 * Here we reset the trace buffer, and set the current
516 * tracer to be this tracer. The tracer can then run some
517 * internal tracing to verify that everything is in order.
518 * If we fail, we do not register this tracer.
520 for_each_tracing_cpu(i
)
521 tracing_reset(tr
, i
);
523 current_trace
= type
;
524 /* the test is responsible for initializing and enabling */
525 pr_info("Testing tracer %s: ", type
->name
);
526 ret
= type
->selftest(type
, tr
);
527 /* the test is responsible for resetting too */
528 current_trace
= saved_tracer
;
530 printk(KERN_CONT
"FAILED!\n");
533 /* Only reset on passing, to avoid touching corrupted buffers */
534 for_each_tracing_cpu(i
)
535 tracing_reset(tr
, i
);
537 printk(KERN_CONT
"PASSED\n");
541 type
->next
= trace_types
;
543 len
= strlen(type
->name
);
544 if (len
> max_tracer_type_len
)
545 max_tracer_type_len
= len
;
548 tracing_selftest_running
= false;
549 mutex_unlock(&trace_types_lock
);
551 if (ret
|| !default_bootup_tracer
)
554 if (strncmp(default_bootup_tracer
, type
->name
, BOOTUP_TRACER_SIZE
))
557 printk(KERN_INFO
"Starting tracer '%s'\n", type
->name
);
558 /* Do we want this tracer to start on bootup? */
559 tracing_set_tracer(type
->name
);
560 default_bootup_tracer
= NULL
;
561 /* disable other selftests, since this will break it. */
562 tracing_selftest_disabled
= 1;
563 #ifdef CONFIG_FTRACE_STARTUP_TEST
564 printk(KERN_INFO
"Disabling FTRACE selftests due to running tracer '%s'\n",
573 void unregister_tracer(struct tracer
*type
)
578 mutex_lock(&trace_types_lock
);
579 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
583 pr_info("Trace %s not registered\n", type
->name
);
589 if (type
== current_trace
&& tracer_enabled
) {
592 if (current_trace
->stop
)
593 current_trace
->stop(&global_trace
);
594 current_trace
= &nop_trace
;
597 if (strlen(type
->name
) != max_tracer_type_len
)
600 max_tracer_type_len
= 0;
601 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
602 len
= strlen((*t
)->name
);
603 if (len
> max_tracer_type_len
)
604 max_tracer_type_len
= len
;
607 mutex_unlock(&trace_types_lock
);
610 void tracing_reset(struct trace_array
*tr
, int cpu
)
612 ftrace_disable_cpu();
613 ring_buffer_reset_cpu(tr
->buffer
, cpu
);
617 void tracing_reset_online_cpus(struct trace_array
*tr
)
621 tr
->time_start
= ftrace_now(tr
->cpu
);
623 for_each_online_cpu(cpu
)
624 tracing_reset(tr
, cpu
);
627 #define SAVED_CMDLINES 128
628 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
629 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
630 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
631 static int cmdline_idx
;
632 static raw_spinlock_t trace_cmdline_lock
= __RAW_SPIN_LOCK_UNLOCKED
;
634 /* temporary disable recording */
635 static atomic_t trace_record_cmdline_disabled __read_mostly
;
637 static void trace_init_cmdlines(void)
639 memset(&map_pid_to_cmdline
, -1, sizeof(map_pid_to_cmdline
));
640 memset(&map_cmdline_to_pid
, -1, sizeof(map_cmdline_to_pid
));
644 static int trace_stop_count
;
645 static DEFINE_SPINLOCK(tracing_start_lock
);
648 * ftrace_off_permanent - disable all ftrace code permanently
650 * This should only be called when a serious anomally has
651 * been detected. This will turn off the function tracing,
652 * ring buffers, and other tracing utilites. It takes no
653 * locks and can be called from any context.
655 void ftrace_off_permanent(void)
657 tracing_disabled
= 1;
659 tracing_off_permanent();
663 * tracing_start - quick start of the tracer
665 * If tracing is enabled but was stopped by tracing_stop,
666 * this will start the tracer back up.
668 void tracing_start(void)
670 struct ring_buffer
*buffer
;
673 if (tracing_disabled
)
676 spin_lock_irqsave(&tracing_start_lock
, flags
);
677 if (--trace_stop_count
) {
678 if (trace_stop_count
< 0) {
679 /* Someone screwed up their debugging */
681 trace_stop_count
= 0;
687 buffer
= global_trace
.buffer
;
689 ring_buffer_record_enable(buffer
);
691 buffer
= max_tr
.buffer
;
693 ring_buffer_record_enable(buffer
);
697 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
701 * tracing_stop - quick stop of the tracer
703 * Light weight way to stop tracing. Use in conjunction with
706 void tracing_stop(void)
708 struct ring_buffer
*buffer
;
712 spin_lock_irqsave(&tracing_start_lock
, flags
);
713 if (trace_stop_count
++)
716 buffer
= global_trace
.buffer
;
718 ring_buffer_record_disable(buffer
);
720 buffer
= max_tr
.buffer
;
722 ring_buffer_record_disable(buffer
);
725 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
728 void trace_stop_cmdline_recording(void);
730 static void trace_save_cmdline(struct task_struct
*tsk
)
735 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
739 * It's not the end of the world if we don't get
740 * the lock, but we also don't want to spin
741 * nor do we want to disable interrupts,
742 * so if we miss here, then better luck next time.
744 if (!__raw_spin_trylock(&trace_cmdline_lock
))
747 idx
= map_pid_to_cmdline
[tsk
->pid
];
748 if (idx
>= SAVED_CMDLINES
) {
749 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
751 map
= map_cmdline_to_pid
[idx
];
752 if (map
<= PID_MAX_DEFAULT
)
753 map_pid_to_cmdline
[map
] = (unsigned)-1;
755 map_pid_to_cmdline
[tsk
->pid
] = idx
;
760 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
762 __raw_spin_unlock(&trace_cmdline_lock
);
765 char *trace_find_cmdline(int pid
)
767 char *cmdline
= "<...>";
773 if (pid
> PID_MAX_DEFAULT
)
776 map
= map_pid_to_cmdline
[pid
];
777 if (map
>= SAVED_CMDLINES
)
780 cmdline
= saved_cmdlines
[map
];
786 void tracing_record_cmdline(struct task_struct
*tsk
)
788 if (atomic_read(&trace_record_cmdline_disabled
))
791 trace_save_cmdline(tsk
);
795 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
,
798 struct task_struct
*tsk
= current
;
800 entry
->preempt_count
= pc
& 0xff;
801 entry
->pid
= (tsk
) ? tsk
->pid
: 0;
802 entry
->tgid
= (tsk
) ? tsk
->tgid
: 0;
804 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
805 (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
807 TRACE_FLAG_IRQS_NOSUPPORT
|
809 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
810 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
811 (need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0);
814 struct ring_buffer_event
*trace_buffer_lock_reserve(struct trace_array
*tr
,
817 unsigned long flags
, int pc
)
819 struct ring_buffer_event
*event
;
821 event
= ring_buffer_lock_reserve(tr
->buffer
, len
);
823 struct trace_entry
*ent
= ring_buffer_event_data(event
);
825 tracing_generic_entry_update(ent
, flags
, pc
);
831 static void ftrace_trace_stack(struct trace_array
*tr
,
832 unsigned long flags
, int skip
, int pc
);
833 static void ftrace_trace_userstack(struct trace_array
*tr
,
834 unsigned long flags
, int pc
);
836 void trace_buffer_unlock_commit(struct trace_array
*tr
,
837 struct ring_buffer_event
*event
,
838 unsigned long flags
, int pc
)
840 ring_buffer_unlock_commit(tr
->buffer
, event
);
842 ftrace_trace_stack(tr
, flags
, 6, pc
);
843 ftrace_trace_userstack(tr
, flags
, pc
);
847 struct ring_buffer_event
*
848 trace_current_buffer_lock_reserve(unsigned char type
, unsigned long len
,
849 unsigned long flags
, int pc
)
851 return trace_buffer_lock_reserve(&global_trace
,
852 type
, len
, flags
, pc
);
855 void trace_current_buffer_unlock_commit(struct ring_buffer_event
*event
,
856 unsigned long flags
, int pc
)
858 return trace_buffer_unlock_commit(&global_trace
, event
, flags
, pc
);
862 trace_function(struct trace_array
*tr
,
863 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
866 struct ring_buffer_event
*event
;
867 struct ftrace_entry
*entry
;
869 /* If we are reading the ring buffer, don't trace */
870 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
873 event
= trace_buffer_lock_reserve(tr
, TRACE_FN
, sizeof(*entry
),
877 entry
= ring_buffer_event_data(event
);
879 entry
->parent_ip
= parent_ip
;
880 ring_buffer_unlock_commit(tr
->buffer
, event
);
883 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
884 static void __trace_graph_entry(struct trace_array
*tr
,
885 struct ftrace_graph_ent
*trace
,
889 struct ring_buffer_event
*event
;
890 struct ftrace_graph_ent_entry
*entry
;
892 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
895 event
= trace_buffer_lock_reserve(&global_trace
, TRACE_GRAPH_ENT
,
896 sizeof(*entry
), flags
, pc
);
899 entry
= ring_buffer_event_data(event
);
900 entry
->graph_ent
= *trace
;
901 ring_buffer_unlock_commit(global_trace
.buffer
, event
);
904 static void __trace_graph_return(struct trace_array
*tr
,
905 struct ftrace_graph_ret
*trace
,
909 struct ring_buffer_event
*event
;
910 struct ftrace_graph_ret_entry
*entry
;
912 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
915 event
= trace_buffer_lock_reserve(&global_trace
, TRACE_GRAPH_RET
,
916 sizeof(*entry
), flags
, pc
);
919 entry
= ring_buffer_event_data(event
);
921 ring_buffer_unlock_commit(global_trace
.buffer
, event
);
926 ftrace(struct trace_array
*tr
, struct trace_array_cpu
*data
,
927 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
930 if (likely(!atomic_read(&data
->disabled
)))
931 trace_function(tr
, ip
, parent_ip
, flags
, pc
);
934 static void __ftrace_trace_stack(struct trace_array
*tr
,
938 #ifdef CONFIG_STACKTRACE
939 struct ring_buffer_event
*event
;
940 struct stack_entry
*entry
;
941 struct stack_trace trace
;
943 event
= trace_buffer_lock_reserve(tr
, TRACE_STACK
,
944 sizeof(*entry
), flags
, pc
);
947 entry
= ring_buffer_event_data(event
);
948 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
950 trace
.nr_entries
= 0;
951 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
953 trace
.entries
= entry
->caller
;
955 save_stack_trace(&trace
);
956 ring_buffer_unlock_commit(tr
->buffer
, event
);
960 static void ftrace_trace_stack(struct trace_array
*tr
,
964 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
967 __ftrace_trace_stack(tr
, flags
, skip
, pc
);
970 void __trace_stack(struct trace_array
*tr
,
974 __ftrace_trace_stack(tr
, flags
, skip
, pc
);
977 static void ftrace_trace_userstack(struct trace_array
*tr
,
978 unsigned long flags
, int pc
)
980 #ifdef CONFIG_STACKTRACE
981 struct ring_buffer_event
*event
;
982 struct userstack_entry
*entry
;
983 struct stack_trace trace
;
985 if (!(trace_flags
& TRACE_ITER_USERSTACKTRACE
))
988 event
= trace_buffer_lock_reserve(tr
, TRACE_USER_STACK
,
989 sizeof(*entry
), flags
, pc
);
992 entry
= ring_buffer_event_data(event
);
994 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
996 trace
.nr_entries
= 0;
997 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
999 trace
.entries
= entry
->caller
;
1001 save_stack_trace_user(&trace
);
1002 ring_buffer_unlock_commit(tr
->buffer
, event
);
1007 static void __trace_userstack(struct trace_array
*tr
, unsigned long flags
)
1009 ftrace_trace_userstack(tr
, flags
, preempt_count());
1014 ftrace_trace_special(void *__tr
,
1015 unsigned long arg1
, unsigned long arg2
, unsigned long arg3
,
1018 struct ring_buffer_event
*event
;
1019 struct trace_array
*tr
= __tr
;
1020 struct special_entry
*entry
;
1022 event
= trace_buffer_lock_reserve(tr
, TRACE_SPECIAL
,
1023 sizeof(*entry
), 0, pc
);
1026 entry
= ring_buffer_event_data(event
);
1030 trace_buffer_unlock_commit(tr
, event
, 0, pc
);
1034 __trace_special(void *__tr
, void *__data
,
1035 unsigned long arg1
, unsigned long arg2
, unsigned long arg3
)
1037 ftrace_trace_special(__tr
, arg1
, arg2
, arg3
, preempt_count());
1041 tracing_sched_switch_trace(struct trace_array
*tr
,
1042 struct task_struct
*prev
,
1043 struct task_struct
*next
,
1044 unsigned long flags
, int pc
)
1046 struct ring_buffer_event
*event
;
1047 struct ctx_switch_entry
*entry
;
1049 event
= trace_buffer_lock_reserve(tr
, TRACE_CTX
,
1050 sizeof(*entry
), flags
, pc
);
1053 entry
= ring_buffer_event_data(event
);
1054 entry
->prev_pid
= prev
->pid
;
1055 entry
->prev_prio
= prev
->prio
;
1056 entry
->prev_state
= prev
->state
;
1057 entry
->next_pid
= next
->pid
;
1058 entry
->next_prio
= next
->prio
;
1059 entry
->next_state
= next
->state
;
1060 entry
->next_cpu
= task_cpu(next
);
1061 trace_buffer_unlock_commit(tr
, event
, flags
, pc
);
1065 tracing_sched_wakeup_trace(struct trace_array
*tr
,
1066 struct task_struct
*wakee
,
1067 struct task_struct
*curr
,
1068 unsigned long flags
, int pc
)
1070 struct ring_buffer_event
*event
;
1071 struct ctx_switch_entry
*entry
;
1073 event
= trace_buffer_lock_reserve(tr
, TRACE_WAKE
,
1074 sizeof(*entry
), flags
, pc
);
1077 entry
= ring_buffer_event_data(event
);
1078 entry
->prev_pid
= curr
->pid
;
1079 entry
->prev_prio
= curr
->prio
;
1080 entry
->prev_state
= curr
->state
;
1081 entry
->next_pid
= wakee
->pid
;
1082 entry
->next_prio
= wakee
->prio
;
1083 entry
->next_state
= wakee
->state
;
1084 entry
->next_cpu
= task_cpu(wakee
);
1086 ring_buffer_unlock_commit(tr
->buffer
, event
);
1087 ftrace_trace_stack(tr
, flags
, 6, pc
);
1088 ftrace_trace_userstack(tr
, flags
, pc
);
1092 ftrace_special(unsigned long arg1
, unsigned long arg2
, unsigned long arg3
)
1094 struct trace_array
*tr
= &global_trace
;
1095 struct trace_array_cpu
*data
;
1096 unsigned long flags
;
1100 if (tracing_disabled
)
1103 pc
= preempt_count();
1104 local_irq_save(flags
);
1105 cpu
= raw_smp_processor_id();
1106 data
= tr
->data
[cpu
];
1108 if (likely(atomic_inc_return(&data
->disabled
) == 1))
1109 ftrace_trace_special(tr
, arg1
, arg2
, arg3
, pc
);
1111 atomic_dec(&data
->disabled
);
1112 local_irq_restore(flags
);
1115 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1116 int trace_graph_entry(struct ftrace_graph_ent
*trace
)
1118 struct trace_array
*tr
= &global_trace
;
1119 struct trace_array_cpu
*data
;
1120 unsigned long flags
;
1125 if (!ftrace_trace_task(current
))
1128 if (!ftrace_graph_addr(trace
->func
))
1131 local_irq_save(flags
);
1132 cpu
= raw_smp_processor_id();
1133 data
= tr
->data
[cpu
];
1134 disabled
= atomic_inc_return(&data
->disabled
);
1135 if (likely(disabled
== 1)) {
1136 pc
= preempt_count();
1137 __trace_graph_entry(tr
, trace
, flags
, pc
);
1139 /* Only do the atomic if it is not already set */
1140 if (!test_tsk_trace_graph(current
))
1141 set_tsk_trace_graph(current
);
1142 atomic_dec(&data
->disabled
);
1143 local_irq_restore(flags
);
1148 void trace_graph_return(struct ftrace_graph_ret
*trace
)
1150 struct trace_array
*tr
= &global_trace
;
1151 struct trace_array_cpu
*data
;
1152 unsigned long flags
;
1157 local_irq_save(flags
);
1158 cpu
= raw_smp_processor_id();
1159 data
= tr
->data
[cpu
];
1160 disabled
= atomic_inc_return(&data
->disabled
);
1161 if (likely(disabled
== 1)) {
1162 pc
= preempt_count();
1163 __trace_graph_return(tr
, trace
, flags
, pc
);
1166 clear_tsk_trace_graph(current
);
1167 atomic_dec(&data
->disabled
);
1168 local_irq_restore(flags
);
1170 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1172 enum trace_file_type
{
1173 TRACE_FILE_LAT_FMT
= 1,
1174 TRACE_FILE_ANNOTATE
= 2,
1177 static void trace_iterator_increment(struct trace_iterator
*iter
)
1179 /* Don't allow ftrace to trace into the ring buffers */
1180 ftrace_disable_cpu();
1183 if (iter
->buffer_iter
[iter
->cpu
])
1184 ring_buffer_read(iter
->buffer_iter
[iter
->cpu
], NULL
);
1186 ftrace_enable_cpu();
1189 static struct trace_entry
*
1190 peek_next_entry(struct trace_iterator
*iter
, int cpu
, u64
*ts
)
1192 struct ring_buffer_event
*event
;
1193 struct ring_buffer_iter
*buf_iter
= iter
->buffer_iter
[cpu
];
1195 /* Don't allow ftrace to trace into the ring buffers */
1196 ftrace_disable_cpu();
1199 event
= ring_buffer_iter_peek(buf_iter
, ts
);
1201 event
= ring_buffer_peek(iter
->tr
->buffer
, cpu
, ts
);
1203 ftrace_enable_cpu();
1205 return event
? ring_buffer_event_data(event
) : NULL
;
1208 static struct trace_entry
*
1209 __find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
, u64
*ent_ts
)
1211 struct ring_buffer
*buffer
= iter
->tr
->buffer
;
1212 struct trace_entry
*ent
, *next
= NULL
;
1213 int cpu_file
= iter
->cpu_file
;
1214 u64 next_ts
= 0, ts
;
1219 * If we are in a per_cpu trace file, don't bother by iterating over
1220 * all cpu and peek directly.
1222 if (cpu_file
> TRACE_PIPE_ALL_CPU
) {
1223 if (ring_buffer_empty_cpu(buffer
, cpu_file
))
1225 ent
= peek_next_entry(iter
, cpu_file
, ent_ts
);
1227 *ent_cpu
= cpu_file
;
1232 for_each_tracing_cpu(cpu
) {
1234 if (ring_buffer_empty_cpu(buffer
, cpu
))
1237 ent
= peek_next_entry(iter
, cpu
, &ts
);
1240 * Pick the entry with the smallest timestamp:
1242 if (ent
&& (!next
|| ts
< next_ts
)) {
1250 *ent_cpu
= next_cpu
;
1258 /* Find the next real entry, without updating the iterator itself */
1259 struct trace_entry
*trace_find_next_entry(struct trace_iterator
*iter
,
1260 int *ent_cpu
, u64
*ent_ts
)
1262 return __find_next_entry(iter
, ent_cpu
, ent_ts
);
1265 /* Find the next real entry, and increment the iterator to the next entry */
1266 static void *find_next_entry_inc(struct trace_iterator
*iter
)
1268 iter
->ent
= __find_next_entry(iter
, &iter
->cpu
, &iter
->ts
);
1271 trace_iterator_increment(iter
);
1273 return iter
->ent
? iter
: NULL
;
1276 static void trace_consume(struct trace_iterator
*iter
)
1278 /* Don't allow ftrace to trace into the ring buffers */
1279 ftrace_disable_cpu();
1280 ring_buffer_consume(iter
->tr
->buffer
, iter
->cpu
, &iter
->ts
);
1281 ftrace_enable_cpu();
1284 static void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1286 struct trace_iterator
*iter
= m
->private;
1292 /* can't go backwards */
1297 ent
= find_next_entry_inc(iter
);
1301 while (ent
&& iter
->idx
< i
)
1302 ent
= find_next_entry_inc(iter
);
1310 * No necessary locking here. The worst thing which can
1311 * happen is loosing events consumed at the same time
1312 * by a trace_pipe reader.
1313 * Other than that, we don't risk to crash the ring buffer
1314 * because it serializes the readers.
1316 * The current tracer is copied to avoid a global locking
1319 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
1321 struct trace_iterator
*iter
= m
->private;
1322 static struct tracer
*old_tracer
;
1323 int cpu_file
= iter
->cpu_file
;
1328 /* copy the tracer to avoid using a global lock all around */
1329 mutex_lock(&trace_types_lock
);
1330 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
1331 old_tracer
= current_trace
;
1332 *iter
->trace
= *current_trace
;
1334 mutex_unlock(&trace_types_lock
);
1336 atomic_inc(&trace_record_cmdline_disabled
);
1338 if (*pos
!= iter
->pos
) {
1343 ftrace_disable_cpu();
1345 if (cpu_file
== TRACE_PIPE_ALL_CPU
) {
1346 for_each_tracing_cpu(cpu
)
1347 ring_buffer_iter_reset(iter
->buffer_iter
[cpu
]);
1349 ring_buffer_iter_reset(iter
->buffer_iter
[cpu_file
]);
1352 ftrace_enable_cpu();
1354 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
1359 p
= s_next(m
, p
, &l
);
1365 static void s_stop(struct seq_file
*m
, void *p
)
1367 atomic_dec(&trace_record_cmdline_disabled
);
1370 static void print_lat_help_header(struct seq_file
*m
)
1372 seq_puts(m
, "# _------=> CPU# \n");
1373 seq_puts(m
, "# / _-----=> irqs-off \n");
1374 seq_puts(m
, "# | / _----=> need-resched \n");
1375 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
1376 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
1377 seq_puts(m
, "# |||| / \n");
1378 seq_puts(m
, "# ||||| delay \n");
1379 seq_puts(m
, "# cmd pid ||||| time | caller \n");
1380 seq_puts(m
, "# \\ / ||||| \\ | / \n");
1383 static void print_func_help_header(struct seq_file
*m
)
1385 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1386 seq_puts(m
, "# | | | | |\n");
1391 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
1393 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1394 struct trace_array
*tr
= iter
->tr
;
1395 struct trace_array_cpu
*data
= tr
->data
[tr
->cpu
];
1396 struct tracer
*type
= current_trace
;
1397 unsigned long total
;
1398 unsigned long entries
;
1399 const char *name
= "preemption";
1404 entries
= ring_buffer_entries(iter
->tr
->buffer
);
1406 ring_buffer_overruns(iter
->tr
->buffer
);
1408 seq_printf(m
, "%s latency trace v1.1.5 on %s\n",
1410 seq_puts(m
, "-----------------------------------"
1411 "---------------------------------\n");
1412 seq_printf(m
, " latency: %lu us, #%lu/%lu, CPU#%d |"
1413 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1414 nsecs_to_usecs(data
->saved_latency
),
1418 #if defined(CONFIG_PREEMPT_NONE)
1420 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1422 #elif defined(CONFIG_PREEMPT)
1427 /* These are reserved for later use */
1430 seq_printf(m
, " #P:%d)\n", num_online_cpus());
1434 seq_puts(m
, " -----------------\n");
1435 seq_printf(m
, " | task: %.16s-%d "
1436 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1437 data
->comm
, data
->pid
, data
->uid
, data
->nice
,
1438 data
->policy
, data
->rt_priority
);
1439 seq_puts(m
, " -----------------\n");
1441 if (data
->critical_start
) {
1442 seq_puts(m
, " => started at: ");
1443 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
1444 trace_print_seq(m
, &iter
->seq
);
1445 seq_puts(m
, "\n => ended at: ");
1446 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
1447 trace_print_seq(m
, &iter
->seq
);
1454 static void test_cpu_buff_start(struct trace_iterator
*iter
)
1456 struct trace_seq
*s
= &iter
->seq
;
1458 if (!(trace_flags
& TRACE_ITER_ANNOTATE
))
1461 if (!(iter
->iter_flags
& TRACE_FILE_ANNOTATE
))
1464 if (cpumask_test_cpu(iter
->cpu
, iter
->started
))
1467 cpumask_set_cpu(iter
->cpu
, iter
->started
);
1468 trace_seq_printf(s
, "##### CPU %u buffer started ####\n", iter
->cpu
);
1471 static enum print_line_t
print_trace_fmt(struct trace_iterator
*iter
)
1473 struct trace_seq
*s
= &iter
->seq
;
1474 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1475 struct trace_entry
*entry
;
1476 struct trace_event
*event
;
1480 test_cpu_buff_start(iter
);
1482 event
= ftrace_find_event(entry
->type
);
1484 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1485 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
1486 if (!trace_print_lat_context(iter
))
1489 if (!trace_print_context(iter
))
1495 return event
->trace(iter
, sym_flags
);
1497 if (!trace_seq_printf(s
, "Unknown type %d\n", entry
->type
))
1500 return TRACE_TYPE_HANDLED
;
1502 return TRACE_TYPE_PARTIAL_LINE
;
1505 static enum print_line_t
print_raw_fmt(struct trace_iterator
*iter
)
1507 struct trace_seq
*s
= &iter
->seq
;
1508 struct trace_entry
*entry
;
1509 struct trace_event
*event
;
1513 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1514 if (!trace_seq_printf(s
, "%d %d %llu ",
1515 entry
->pid
, iter
->cpu
, iter
->ts
))
1519 event
= ftrace_find_event(entry
->type
);
1521 return event
->raw(iter
, 0);
1523 if (!trace_seq_printf(s
, "%d ?\n", entry
->type
))
1526 return TRACE_TYPE_HANDLED
;
1528 return TRACE_TYPE_PARTIAL_LINE
;
1531 static enum print_line_t
print_hex_fmt(struct trace_iterator
*iter
)
1533 struct trace_seq
*s
= &iter
->seq
;
1534 unsigned char newline
= '\n';
1535 struct trace_entry
*entry
;
1536 struct trace_event
*event
;
1540 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1541 SEQ_PUT_HEX_FIELD_RET(s
, entry
->pid
);
1542 SEQ_PUT_HEX_FIELD_RET(s
, iter
->cpu
);
1543 SEQ_PUT_HEX_FIELD_RET(s
, iter
->ts
);
1546 event
= ftrace_find_event(entry
->type
);
1548 enum print_line_t ret
= event
->hex(iter
, 0);
1549 if (ret
!= TRACE_TYPE_HANDLED
)
1553 SEQ_PUT_FIELD_RET(s
, newline
);
1555 return TRACE_TYPE_HANDLED
;
1558 static enum print_line_t
print_printk_msg_only(struct trace_iterator
*iter
)
1560 struct trace_seq
*s
= &iter
->seq
;
1561 struct trace_entry
*entry
= iter
->ent
;
1562 struct print_entry
*field
;
1565 trace_assign_type(field
, entry
);
1567 ret
= trace_seq_printf(s
, "%s", field
->buf
);
1569 return TRACE_TYPE_PARTIAL_LINE
;
1571 return TRACE_TYPE_HANDLED
;
1574 static enum print_line_t
print_bin_fmt(struct trace_iterator
*iter
)
1576 struct trace_seq
*s
= &iter
->seq
;
1577 struct trace_entry
*entry
;
1578 struct trace_event
*event
;
1582 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1583 SEQ_PUT_FIELD_RET(s
, entry
->pid
);
1584 SEQ_PUT_FIELD_RET(s
, iter
->cpu
);
1585 SEQ_PUT_FIELD_RET(s
, iter
->ts
);
1588 event
= ftrace_find_event(entry
->type
);
1589 return event
? event
->binary(iter
, 0) : TRACE_TYPE_HANDLED
;
1592 static int trace_empty(struct trace_iterator
*iter
)
1596 for_each_tracing_cpu(cpu
) {
1597 if (iter
->buffer_iter
[cpu
]) {
1598 if (!ring_buffer_iter_empty(iter
->buffer_iter
[cpu
]))
1601 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
1609 static enum print_line_t
print_trace_line(struct trace_iterator
*iter
)
1611 enum print_line_t ret
;
1613 if (iter
->trace
&& iter
->trace
->print_line
) {
1614 ret
= iter
->trace
->print_line(iter
);
1615 if (ret
!= TRACE_TYPE_UNHANDLED
)
1619 if (iter
->ent
->type
== TRACE_PRINT
&&
1620 trace_flags
& TRACE_ITER_PRINTK
&&
1621 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
1622 return print_printk_msg_only(iter
);
1624 if (trace_flags
& TRACE_ITER_BIN
)
1625 return print_bin_fmt(iter
);
1627 if (trace_flags
& TRACE_ITER_HEX
)
1628 return print_hex_fmt(iter
);
1630 if (trace_flags
& TRACE_ITER_RAW
)
1631 return print_raw_fmt(iter
);
1633 return print_trace_fmt(iter
);
1636 static int s_show(struct seq_file
*m
, void *v
)
1638 struct trace_iterator
*iter
= v
;
1640 if (iter
->ent
== NULL
) {
1642 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
1645 if (iter
->trace
&& iter
->trace
->print_header
)
1646 iter
->trace
->print_header(m
);
1647 else if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
1648 /* print nothing if the buffers are empty */
1649 if (trace_empty(iter
))
1651 print_trace_header(m
, iter
);
1652 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1653 print_lat_help_header(m
);
1655 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1656 print_func_help_header(m
);
1659 print_trace_line(iter
);
1660 trace_print_seq(m
, &iter
->seq
);
1666 static struct seq_operations tracer_seq_ops
= {
1673 static struct trace_iterator
*
1674 __tracing_open(struct inode
*inode
, struct file
*file
)
1676 long cpu_file
= (long) inode
->i_private
;
1677 void *fail_ret
= ERR_PTR(-ENOMEM
);
1678 struct trace_iterator
*iter
;
1682 if (tracing_disabled
)
1683 return ERR_PTR(-ENODEV
);
1685 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
1687 return ERR_PTR(-ENOMEM
);
1690 * We make a copy of the current tracer to avoid concurrent
1691 * changes on it while we are reading.
1693 mutex_lock(&trace_types_lock
);
1694 iter
->trace
= kzalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
1699 *iter
->trace
= *current_trace
;
1701 if (current_trace
&& current_trace
->print_max
)
1704 iter
->tr
= &global_trace
;
1706 mutex_init(&iter
->mutex
);
1707 iter
->cpu_file
= cpu_file
;
1709 /* Notify the tracer early; before we stop tracing. */
1710 if (iter
->trace
&& iter
->trace
->open
)
1711 iter
->trace
->open(iter
);
1713 /* Annotate start of buffers if we had overruns */
1714 if (ring_buffer_overruns(iter
->tr
->buffer
))
1715 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
1717 if (iter
->cpu_file
== TRACE_PIPE_ALL_CPU
) {
1718 for_each_tracing_cpu(cpu
) {
1720 iter
->buffer_iter
[cpu
] =
1721 ring_buffer_read_start(iter
->tr
->buffer
, cpu
);
1723 if (!iter
->buffer_iter
[cpu
])
1727 cpu
= iter
->cpu_file
;
1728 iter
->buffer_iter
[cpu
] =
1729 ring_buffer_read_start(iter
->tr
->buffer
, cpu
);
1731 if (!iter
->buffer_iter
[cpu
])
1735 /* TODO stop tracer */
1736 ret
= seq_open(file
, &tracer_seq_ops
);
1738 fail_ret
= ERR_PTR(ret
);
1742 m
= file
->private_data
;
1745 /* stop the trace while dumping */
1748 mutex_unlock(&trace_types_lock
);
1753 for_each_tracing_cpu(cpu
) {
1754 if (iter
->buffer_iter
[cpu
])
1755 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
1758 mutex_unlock(&trace_types_lock
);
1765 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
1767 if (tracing_disabled
)
1770 filp
->private_data
= inode
->i_private
;
1774 static int tracing_release(struct inode
*inode
, struct file
*file
)
1776 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
1777 struct trace_iterator
*iter
= m
->private;
1780 mutex_lock(&trace_types_lock
);
1781 for_each_tracing_cpu(cpu
) {
1782 if (iter
->buffer_iter
[cpu
])
1783 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
1786 if (iter
->trace
&& iter
->trace
->close
)
1787 iter
->trace
->close(iter
);
1789 /* reenable tracing if it was previously enabled */
1791 mutex_unlock(&trace_types_lock
);
1793 seq_release(inode
, file
);
1794 mutex_destroy(&iter
->mutex
);
1800 static int tracing_open(struct inode
*inode
, struct file
*file
)
1802 struct trace_iterator
*iter
;
1805 iter
= __tracing_open(inode
, file
);
1807 ret
= PTR_ERR(iter
);
1808 else if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
1809 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
1815 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1817 struct tracer
*t
= m
->private;
1829 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
1831 struct tracer
*t
= m
->private;
1834 mutex_lock(&trace_types_lock
);
1835 for (; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
1841 static void t_stop(struct seq_file
*m
, void *p
)
1843 mutex_unlock(&trace_types_lock
);
1846 static int t_show(struct seq_file
*m
, void *v
)
1848 struct tracer
*t
= v
;
1853 seq_printf(m
, "%s", t
->name
);
1862 static struct seq_operations show_traces_seq_ops
= {
1869 static int show_traces_open(struct inode
*inode
, struct file
*file
)
1873 if (tracing_disabled
)
1876 ret
= seq_open(file
, &show_traces_seq_ops
);
1878 struct seq_file
*m
= file
->private_data
;
1879 m
->private = trace_types
;
1885 static struct file_operations tracing_fops
= {
1886 .open
= tracing_open
,
1888 .llseek
= seq_lseek
,
1889 .release
= tracing_release
,
1892 static struct file_operations show_traces_fops
= {
1893 .open
= show_traces_open
,
1895 .release
= seq_release
,
1899 * Only trace on a CPU if the bitmask is set:
1901 static cpumask_var_t tracing_cpumask
;
1904 * The tracer itself will not take this lock, but still we want
1905 * to provide a consistent cpumask to user-space:
1907 static DEFINE_MUTEX(tracing_cpumask_update_lock
);
1910 * Temporary storage for the character representation of the
1911 * CPU bitmask (and one more byte for the newline):
1913 static char mask_str
[NR_CPUS
+ 1];
1916 tracing_cpumask_read(struct file
*filp
, char __user
*ubuf
,
1917 size_t count
, loff_t
*ppos
)
1921 mutex_lock(&tracing_cpumask_update_lock
);
1923 len
= cpumask_scnprintf(mask_str
, count
, tracing_cpumask
);
1924 if (count
- len
< 2) {
1928 len
+= sprintf(mask_str
+ len
, "\n");
1929 count
= simple_read_from_buffer(ubuf
, count
, ppos
, mask_str
, NR_CPUS
+1);
1932 mutex_unlock(&tracing_cpumask_update_lock
);
1938 tracing_cpumask_write(struct file
*filp
, const char __user
*ubuf
,
1939 size_t count
, loff_t
*ppos
)
1942 cpumask_var_t tracing_cpumask_new
;
1944 if (!alloc_cpumask_var(&tracing_cpumask_new
, GFP_KERNEL
))
1947 mutex_lock(&tracing_cpumask_update_lock
);
1948 err
= cpumask_parse_user(ubuf
, count
, tracing_cpumask_new
);
1952 local_irq_disable();
1953 __raw_spin_lock(&ftrace_max_lock
);
1954 for_each_tracing_cpu(cpu
) {
1956 * Increase/decrease the disabled counter if we are
1957 * about to flip a bit in the cpumask:
1959 if (cpumask_test_cpu(cpu
, tracing_cpumask
) &&
1960 !cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
1961 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
1963 if (!cpumask_test_cpu(cpu
, tracing_cpumask
) &&
1964 cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
1965 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
1968 __raw_spin_unlock(&ftrace_max_lock
);
1971 cpumask_copy(tracing_cpumask
, tracing_cpumask_new
);
1973 mutex_unlock(&tracing_cpumask_update_lock
);
1974 free_cpumask_var(tracing_cpumask_new
);
1979 mutex_unlock(&tracing_cpumask_update_lock
);
1980 free_cpumask_var(tracing_cpumask
);
1985 static struct file_operations tracing_cpumask_fops
= {
1986 .open
= tracing_open_generic
,
1987 .read
= tracing_cpumask_read
,
1988 .write
= tracing_cpumask_write
,
1992 tracing_trace_options_read(struct file
*filp
, char __user
*ubuf
,
1993 size_t cnt
, loff_t
*ppos
)
1995 struct tracer_opt
*trace_opts
;
2003 /* calculate max size */
2004 for (i
= 0; trace_options
[i
]; i
++) {
2005 len
+= strlen(trace_options
[i
]);
2006 len
+= 3; /* "no" and newline */
2009 mutex_lock(&trace_types_lock
);
2010 tracer_flags
= current_trace
->flags
->val
;
2011 trace_opts
= current_trace
->flags
->opts
;
2014 * Increase the size with names of options specific
2015 * of the current tracer.
2017 for (i
= 0; trace_opts
[i
].name
; i
++) {
2018 len
+= strlen(trace_opts
[i
].name
);
2019 len
+= 3; /* "no" and newline */
2022 /* +2 for \n and \0 */
2023 buf
= kmalloc(len
+ 2, GFP_KERNEL
);
2025 mutex_unlock(&trace_types_lock
);
2029 for (i
= 0; trace_options
[i
]; i
++) {
2030 if (trace_flags
& (1 << i
))
2031 r
+= sprintf(buf
+ r
, "%s\n", trace_options
[i
]);
2033 r
+= sprintf(buf
+ r
, "no%s\n", trace_options
[i
]);
2036 for (i
= 0; trace_opts
[i
].name
; i
++) {
2037 if (tracer_flags
& trace_opts
[i
].bit
)
2038 r
+= sprintf(buf
+ r
, "%s\n",
2039 trace_opts
[i
].name
);
2041 r
+= sprintf(buf
+ r
, "no%s\n",
2042 trace_opts
[i
].name
);
2044 mutex_unlock(&trace_types_lock
);
2046 WARN_ON(r
>= len
+ 2);
2048 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2054 /* Try to assign a tracer specific option */
2055 static int set_tracer_option(struct tracer
*trace
, char *cmp
, int neg
)
2057 struct tracer_flags
*trace_flags
= trace
->flags
;
2058 struct tracer_opt
*opts
= NULL
;
2062 for (i
= 0; trace_flags
->opts
[i
].name
; i
++) {
2063 opts
= &trace_flags
->opts
[i
];
2064 len
= strlen(opts
->name
);
2066 if (strncmp(cmp
, opts
->name
, len
) == 0) {
2067 ret
= trace
->set_flag(trace_flags
->val
,
2073 if (!trace_flags
->opts
[i
].name
)
2076 /* Refused to handle */
2081 trace_flags
->val
&= ~opts
->bit
;
2083 trace_flags
->val
|= opts
->bit
;
2089 tracing_trace_options_write(struct file
*filp
, const char __user
*ubuf
,
2090 size_t cnt
, loff_t
*ppos
)
2098 if (cnt
>= sizeof(buf
))
2101 if (copy_from_user(&buf
, ubuf
, cnt
))
2106 if (strncmp(buf
, "no", 2) == 0) {
2111 for (i
= 0; trace_options
[i
]; i
++) {
2112 int len
= strlen(trace_options
[i
]);
2114 if (strncmp(cmp
, trace_options
[i
], len
) == 0) {
2116 trace_flags
&= ~(1 << i
);
2118 trace_flags
|= (1 << i
);
2123 /* If no option could be set, test the specific tracer options */
2124 if (!trace_options
[i
]) {
2125 mutex_lock(&trace_types_lock
);
2126 ret
= set_tracer_option(current_trace
, cmp
, neg
);
2127 mutex_unlock(&trace_types_lock
);
2137 static struct file_operations tracing_iter_fops
= {
2138 .open
= tracing_open_generic
,
2139 .read
= tracing_trace_options_read
,
2140 .write
= tracing_trace_options_write
,
2143 static const char readme_msg
[] =
2144 "tracing mini-HOWTO:\n\n"
2146 "# mount -t debugfs nodev /debug\n\n"
2147 "# cat /debug/tracing/available_tracers\n"
2148 "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
2149 "# cat /debug/tracing/current_tracer\n"
2151 "# echo sched_switch > /debug/tracing/current_tracer\n"
2152 "# cat /debug/tracing/current_tracer\n"
2154 "# cat /debug/tracing/trace_options\n"
2155 "noprint-parent nosym-offset nosym-addr noverbose\n"
2156 "# echo print-parent > /debug/tracing/trace_options\n"
2157 "# echo 1 > /debug/tracing/tracing_enabled\n"
2158 "# cat /debug/tracing/trace > /tmp/trace.txt\n"
2159 "echo 0 > /debug/tracing/tracing_enabled\n"
2163 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
2164 size_t cnt
, loff_t
*ppos
)
2166 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
2167 readme_msg
, strlen(readme_msg
));
2170 static struct file_operations tracing_readme_fops
= {
2171 .open
= tracing_open_generic
,
2172 .read
= tracing_readme_read
,
2176 tracing_ctrl_read(struct file
*filp
, char __user
*ubuf
,
2177 size_t cnt
, loff_t
*ppos
)
2182 r
= sprintf(buf
, "%u\n", tracer_enabled
);
2183 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2187 tracing_ctrl_write(struct file
*filp
, const char __user
*ubuf
,
2188 size_t cnt
, loff_t
*ppos
)
2190 struct trace_array
*tr
= filp
->private_data
;
2195 if (cnt
>= sizeof(buf
))
2198 if (copy_from_user(&buf
, ubuf
, cnt
))
2203 ret
= strict_strtoul(buf
, 10, &val
);
2209 mutex_lock(&trace_types_lock
);
2210 if (tracer_enabled
^ val
) {
2213 if (current_trace
->start
)
2214 current_trace
->start(tr
);
2219 if (current_trace
->stop
)
2220 current_trace
->stop(tr
);
2223 mutex_unlock(&trace_types_lock
);
2231 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
2232 size_t cnt
, loff_t
*ppos
)
2234 char buf
[max_tracer_type_len
+2];
2237 mutex_lock(&trace_types_lock
);
2239 r
= sprintf(buf
, "%s\n", current_trace
->name
);
2241 r
= sprintf(buf
, "\n");
2242 mutex_unlock(&trace_types_lock
);
2244 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2247 int tracer_init(struct tracer
*t
, struct trace_array
*tr
)
2249 tracing_reset_online_cpus(tr
);
2253 struct trace_option_dentry
;
2255 static struct trace_option_dentry
*
2256 create_trace_option_files(struct tracer
*tracer
);
2259 destroy_trace_option_files(struct trace_option_dentry
*topts
);
2261 static int tracing_set_tracer(const char *buf
)
2263 static struct trace_option_dentry
*topts
;
2264 struct trace_array
*tr
= &global_trace
;
2268 mutex_lock(&trace_types_lock
);
2269 for (t
= trace_types
; t
; t
= t
->next
) {
2270 if (strcmp(t
->name
, buf
) == 0)
2277 if (t
== current_trace
)
2280 trace_branch_disable();
2281 if (current_trace
&& current_trace
->reset
)
2282 current_trace
->reset(tr
);
2284 destroy_trace_option_files(topts
);
2288 topts
= create_trace_option_files(current_trace
);
2291 ret
= tracer_init(t
, tr
);
2296 trace_branch_enable(tr
);
2298 mutex_unlock(&trace_types_lock
);
2304 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
2305 size_t cnt
, loff_t
*ppos
)
2307 char buf
[max_tracer_type_len
+1];
2314 if (cnt
> max_tracer_type_len
)
2315 cnt
= max_tracer_type_len
;
2317 if (copy_from_user(&buf
, ubuf
, cnt
))
2322 /* strip ending whitespace. */
2323 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
2326 err
= tracing_set_tracer(buf
);
2336 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
2337 size_t cnt
, loff_t
*ppos
)
2339 unsigned long *ptr
= filp
->private_data
;
2343 r
= snprintf(buf
, sizeof(buf
), "%ld\n",
2344 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
2345 if (r
> sizeof(buf
))
2347 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2351 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
2352 size_t cnt
, loff_t
*ppos
)
2354 unsigned long *ptr
= filp
->private_data
;
2359 if (cnt
>= sizeof(buf
))
2362 if (copy_from_user(&buf
, ubuf
, cnt
))
2367 ret
= strict_strtoul(buf
, 10, &val
);
2376 static int tracing_open_pipe(struct inode
*inode
, struct file
*filp
)
2378 long cpu_file
= (long) inode
->i_private
;
2379 struct trace_iterator
*iter
;
2382 if (tracing_disabled
)
2385 mutex_lock(&trace_types_lock
);
2387 /* We only allow one reader per cpu */
2388 if (cpu_file
== TRACE_PIPE_ALL_CPU
) {
2389 if (!cpumask_empty(tracing_reader_cpumask
)) {
2393 cpumask_setall(tracing_reader_cpumask
);
2395 if (!cpumask_test_cpu(cpu_file
, tracing_reader_cpumask
))
2396 cpumask_set_cpu(cpu_file
, tracing_reader_cpumask
);
2403 /* create a buffer to store the information to pass to userspace */
2404 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2411 * We make a copy of the current tracer to avoid concurrent
2412 * changes on it while we are reading.
2414 iter
->trace
= kmalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
2420 *iter
->trace
= *current_trace
;
2422 if (!alloc_cpumask_var(&iter
->started
, GFP_KERNEL
)) {
2427 /* trace pipe does not show start of buffer */
2428 cpumask_setall(iter
->started
);
2430 iter
->cpu_file
= cpu_file
;
2431 iter
->tr
= &global_trace
;
2432 mutex_init(&iter
->mutex
);
2433 filp
->private_data
= iter
;
2435 if (iter
->trace
->pipe_open
)
2436 iter
->trace
->pipe_open(iter
);
2439 mutex_unlock(&trace_types_lock
);
2445 mutex_unlock(&trace_types_lock
);
2449 static int tracing_release_pipe(struct inode
*inode
, struct file
*file
)
2451 struct trace_iterator
*iter
= file
->private_data
;
2453 mutex_lock(&trace_types_lock
);
2455 if (iter
->cpu_file
== TRACE_PIPE_ALL_CPU
)
2456 cpumask_clear(tracing_reader_cpumask
);
2458 cpumask_clear_cpu(iter
->cpu_file
, tracing_reader_cpumask
);
2460 mutex_unlock(&trace_types_lock
);
2462 free_cpumask_var(iter
->started
);
2463 mutex_destroy(&iter
->mutex
);
2471 tracing_poll_pipe(struct file
*filp
, poll_table
*poll_table
)
2473 struct trace_iterator
*iter
= filp
->private_data
;
2475 if (trace_flags
& TRACE_ITER_BLOCK
) {
2477 * Always select as readable when in blocking mode
2479 return POLLIN
| POLLRDNORM
;
2481 if (!trace_empty(iter
))
2482 return POLLIN
| POLLRDNORM
;
2483 poll_wait(filp
, &trace_wait
, poll_table
);
2484 if (!trace_empty(iter
))
2485 return POLLIN
| POLLRDNORM
;
2492 void default_wait_pipe(struct trace_iterator
*iter
)
2496 prepare_to_wait(&trace_wait
, &wait
, TASK_INTERRUPTIBLE
);
2498 if (trace_empty(iter
))
2501 finish_wait(&trace_wait
, &wait
);
2505 * This is a make-shift waitqueue.
2506 * A tracer might use this callback on some rare cases:
2508 * 1) the current tracer might hold the runqueue lock when it wakes up
2509 * a reader, hence a deadlock (sched, function, and function graph tracers)
2510 * 2) the function tracers, trace all functions, we don't want
2511 * the overhead of calling wake_up and friends
2512 * (and tracing them too)
2514 * Anyway, this is really very primitive wakeup.
2516 void poll_wait_pipe(struct trace_iterator
*iter
)
2518 set_current_state(TASK_INTERRUPTIBLE
);
2519 /* sleep for 100 msecs, and try again. */
2520 schedule_timeout(HZ
/ 10);
2523 /* Must be called with trace_types_lock mutex held. */
2524 static int tracing_wait_pipe(struct file
*filp
)
2526 struct trace_iterator
*iter
= filp
->private_data
;
2528 while (trace_empty(iter
)) {
2530 if ((filp
->f_flags
& O_NONBLOCK
)) {
2534 mutex_unlock(&iter
->mutex
);
2536 iter
->trace
->wait_pipe(iter
);
2538 mutex_lock(&iter
->mutex
);
2540 if (signal_pending(current
))
2544 * We block until we read something and tracing is disabled.
2545 * We still block if tracing is disabled, but we have never
2546 * read anything. This allows a user to cat this file, and
2547 * then enable tracing. But after we have read something,
2548 * we give an EOF when tracing is again disabled.
2550 * iter->pos will be 0 if we haven't read anything.
2552 if (!tracer_enabled
&& iter
->pos
)
2563 tracing_read_pipe(struct file
*filp
, char __user
*ubuf
,
2564 size_t cnt
, loff_t
*ppos
)
2566 struct trace_iterator
*iter
= filp
->private_data
;
2567 static struct tracer
*old_tracer
;
2570 /* return any leftover data */
2571 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
2575 trace_seq_init(&iter
->seq
);
2577 /* copy the tracer to avoid using a global lock all around */
2578 mutex_lock(&trace_types_lock
);
2579 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
2580 old_tracer
= current_trace
;
2581 *iter
->trace
= *current_trace
;
2583 mutex_unlock(&trace_types_lock
);
2586 * Avoid more than one consumer on a single file descriptor
2587 * This is just a matter of traces coherency, the ring buffer itself
2590 mutex_lock(&iter
->mutex
);
2591 if (iter
->trace
->read
) {
2592 sret
= iter
->trace
->read(iter
, filp
, ubuf
, cnt
, ppos
);
2598 sret
= tracing_wait_pipe(filp
);
2602 /* stop when tracing is finished */
2603 if (trace_empty(iter
)) {
2608 if (cnt
>= PAGE_SIZE
)
2609 cnt
= PAGE_SIZE
- 1;
2611 /* reset all but tr, trace, and overruns */
2612 memset(&iter
->seq
, 0,
2613 sizeof(struct trace_iterator
) -
2614 offsetof(struct trace_iterator
, seq
));
2617 while (find_next_entry_inc(iter
) != NULL
) {
2618 enum print_line_t ret
;
2619 int len
= iter
->seq
.len
;
2621 ret
= print_trace_line(iter
);
2622 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
2623 /* don't print partial lines */
2624 iter
->seq
.len
= len
;
2627 if (ret
!= TRACE_TYPE_NO_CONSUME
)
2628 trace_consume(iter
);
2630 if (iter
->seq
.len
>= cnt
)
2634 /* Now copy what we have to the user */
2635 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
2636 if (iter
->seq
.readpos
>= iter
->seq
.len
)
2637 trace_seq_init(&iter
->seq
);
2640 * If there was nothing to send to user, inspite of consuming trace
2641 * entries, go back to wait for more entries.
2647 mutex_unlock(&iter
->mutex
);
2652 static void tracing_pipe_buf_release(struct pipe_inode_info
*pipe
,
2653 struct pipe_buffer
*buf
)
2655 __free_page(buf
->page
);
2658 static void tracing_spd_release_pipe(struct splice_pipe_desc
*spd
,
2661 __free_page(spd
->pages
[idx
]);
2664 static struct pipe_buf_operations tracing_pipe_buf_ops
= {
2666 .map
= generic_pipe_buf_map
,
2667 .unmap
= generic_pipe_buf_unmap
,
2668 .confirm
= generic_pipe_buf_confirm
,
2669 .release
= tracing_pipe_buf_release
,
2670 .steal
= generic_pipe_buf_steal
,
2671 .get
= generic_pipe_buf_get
,
2675 tracing_fill_pipe_page(size_t rem
, struct trace_iterator
*iter
)
2680 /* Seq buffer is page-sized, exactly what we need. */
2682 count
= iter
->seq
.len
;
2683 ret
= print_trace_line(iter
);
2684 count
= iter
->seq
.len
- count
;
2687 iter
->seq
.len
-= count
;
2690 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
2691 iter
->seq
.len
-= count
;
2695 trace_consume(iter
);
2697 if (!find_next_entry_inc(iter
)) {
2707 static ssize_t
tracing_splice_read_pipe(struct file
*filp
,
2709 struct pipe_inode_info
*pipe
,
2713 struct page
*pages
[PIPE_BUFFERS
];
2714 struct partial_page partial
[PIPE_BUFFERS
];
2715 struct trace_iterator
*iter
= filp
->private_data
;
2716 struct splice_pipe_desc spd
= {
2719 .nr_pages
= 0, /* This gets updated below. */
2721 .ops
= &tracing_pipe_buf_ops
,
2722 .spd_release
= tracing_spd_release_pipe
,
2724 static struct tracer
*old_tracer
;
2729 /* copy the tracer to avoid using a global lock all around */
2730 mutex_lock(&trace_types_lock
);
2731 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
2732 old_tracer
= current_trace
;
2733 *iter
->trace
= *current_trace
;
2735 mutex_unlock(&trace_types_lock
);
2737 mutex_lock(&iter
->mutex
);
2739 if (iter
->trace
->splice_read
) {
2740 ret
= iter
->trace
->splice_read(iter
, filp
,
2741 ppos
, pipe
, len
, flags
);
2746 ret
= tracing_wait_pipe(filp
);
2750 if (!iter
->ent
&& !find_next_entry_inc(iter
)) {
2755 /* Fill as many pages as possible. */
2756 for (i
= 0, rem
= len
; i
< PIPE_BUFFERS
&& rem
; i
++) {
2757 pages
[i
] = alloc_page(GFP_KERNEL
);
2761 rem
= tracing_fill_pipe_page(rem
, iter
);
2763 /* Copy the data into the page, so we can start over. */
2764 ret
= trace_seq_to_buffer(&iter
->seq
,
2765 page_address(pages
[i
]),
2768 __free_page(pages
[i
]);
2771 partial
[i
].offset
= 0;
2772 partial
[i
].len
= iter
->seq
.len
;
2774 trace_seq_init(&iter
->seq
);
2777 mutex_unlock(&iter
->mutex
);
2781 return splice_to_pipe(pipe
, &spd
);
2784 mutex_unlock(&iter
->mutex
);
2790 tracing_entries_read(struct file
*filp
, char __user
*ubuf
,
2791 size_t cnt
, loff_t
*ppos
)
2793 struct trace_array
*tr
= filp
->private_data
;
2797 r
= sprintf(buf
, "%lu\n", tr
->entries
>> 10);
2798 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2802 tracing_entries_write(struct file
*filp
, const char __user
*ubuf
,
2803 size_t cnt
, loff_t
*ppos
)
2809 if (cnt
>= sizeof(buf
))
2812 if (copy_from_user(&buf
, ubuf
, cnt
))
2817 ret
= strict_strtoul(buf
, 10, &val
);
2821 /* must have at least 1 entry */
2825 mutex_lock(&trace_types_lock
);
2829 /* disable all cpu buffers */
2830 for_each_tracing_cpu(cpu
) {
2831 if (global_trace
.data
[cpu
])
2832 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
2833 if (max_tr
.data
[cpu
])
2834 atomic_inc(&max_tr
.data
[cpu
]->disabled
);
2837 /* value is in KB */
2840 if (val
!= global_trace
.entries
) {
2841 ret
= ring_buffer_resize(global_trace
.buffer
, val
);
2847 ret
= ring_buffer_resize(max_tr
.buffer
, val
);
2851 r
= ring_buffer_resize(global_trace
.buffer
,
2852 global_trace
.entries
);
2854 /* AARGH! We are left with different
2855 * size max buffer!!!! */
2857 tracing_disabled
= 1;
2862 global_trace
.entries
= val
;
2867 /* If check pages failed, return ENOMEM */
2868 if (tracing_disabled
)
2871 for_each_tracing_cpu(cpu
) {
2872 if (global_trace
.data
[cpu
])
2873 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
2874 if (max_tr
.data
[cpu
])
2875 atomic_dec(&max_tr
.data
[cpu
]->disabled
);
2879 max_tr
.entries
= global_trace
.entries
;
2880 mutex_unlock(&trace_types_lock
);
2885 static int mark_printk(const char *fmt
, ...)
2889 va_start(args
, fmt
);
2890 ret
= trace_vprintk(0, -1, fmt
, args
);
2896 tracing_mark_write(struct file
*filp
, const char __user
*ubuf
,
2897 size_t cnt
, loff_t
*fpos
)
2902 if (tracing_disabled
)
2905 if (cnt
> TRACE_BUF_SIZE
)
2906 cnt
= TRACE_BUF_SIZE
;
2908 buf
= kmalloc(cnt
+ 1, GFP_KERNEL
);
2912 if (copy_from_user(buf
, ubuf
, cnt
)) {
2917 /* Cut from the first nil or newline. */
2919 end
= strchr(buf
, '\n');
2923 cnt
= mark_printk("%s\n", buf
);
2930 static struct file_operations tracing_max_lat_fops
= {
2931 .open
= tracing_open_generic
,
2932 .read
= tracing_max_lat_read
,
2933 .write
= tracing_max_lat_write
,
2936 static struct file_operations tracing_ctrl_fops
= {
2937 .open
= tracing_open_generic
,
2938 .read
= tracing_ctrl_read
,
2939 .write
= tracing_ctrl_write
,
2942 static struct file_operations set_tracer_fops
= {
2943 .open
= tracing_open_generic
,
2944 .read
= tracing_set_trace_read
,
2945 .write
= tracing_set_trace_write
,
2948 static struct file_operations tracing_pipe_fops
= {
2949 .open
= tracing_open_pipe
,
2950 .poll
= tracing_poll_pipe
,
2951 .read
= tracing_read_pipe
,
2952 .splice_read
= tracing_splice_read_pipe
,
2953 .release
= tracing_release_pipe
,
2956 static struct file_operations tracing_entries_fops
= {
2957 .open
= tracing_open_generic
,
2958 .read
= tracing_entries_read
,
2959 .write
= tracing_entries_write
,
2962 static struct file_operations tracing_mark_fops
= {
2963 .open
= tracing_open_generic
,
2964 .write
= tracing_mark_write
,
2967 struct ftrace_buffer_info
{
2968 struct trace_array
*tr
;
2974 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
)
2976 int cpu
= (int)(long)inode
->i_private
;
2977 struct ftrace_buffer_info
*info
;
2979 if (tracing_disabled
)
2982 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
2986 info
->tr
= &global_trace
;
2988 info
->spare
= ring_buffer_alloc_read_page(info
->tr
->buffer
);
2989 /* Force reading ring buffer for first read */
2990 info
->read
= (unsigned int)-1;
2994 filp
->private_data
= info
;
3004 tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
3005 size_t count
, loff_t
*ppos
)
3007 struct ftrace_buffer_info
*info
= filp
->private_data
;
3015 /* Do we have previous read data to read? */
3016 if (info
->read
< PAGE_SIZE
)
3021 ret
= ring_buffer_read_page(info
->tr
->buffer
,
3028 pos
= ring_buffer_page_len(info
->spare
);
3030 if (pos
< PAGE_SIZE
)
3031 memset(info
->spare
+ pos
, 0, PAGE_SIZE
- pos
);
3034 size
= PAGE_SIZE
- info
->read
;
3038 ret
= copy_to_user(ubuf
, info
->spare
+ info
->read
, size
);
3049 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
)
3051 struct ftrace_buffer_info
*info
= file
->private_data
;
3053 ring_buffer_free_read_page(info
->tr
->buffer
, info
->spare
);
3060 struct ring_buffer
*buffer
;
3065 static void buffer_pipe_buf_release(struct pipe_inode_info
*pipe
,
3066 struct pipe_buffer
*buf
)
3068 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
3073 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
3078 static int buffer_pipe_buf_steal(struct pipe_inode_info
*pipe
,
3079 struct pipe_buffer
*buf
)
3084 static void buffer_pipe_buf_get(struct pipe_inode_info
*pipe
,
3085 struct pipe_buffer
*buf
)
3087 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
3092 /* Pipe buffer operations for a buffer. */
3093 static struct pipe_buf_operations buffer_pipe_buf_ops
= {
3095 .map
= generic_pipe_buf_map
,
3096 .unmap
= generic_pipe_buf_unmap
,
3097 .confirm
= generic_pipe_buf_confirm
,
3098 .release
= buffer_pipe_buf_release
,
3099 .steal
= buffer_pipe_buf_steal
,
3100 .get
= buffer_pipe_buf_get
,
3104 * Callback from splice_to_pipe(), if we need to release some pages
3105 * at the end of the spd in case we error'ed out in filling the pipe.
3107 static void buffer_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
3109 struct buffer_ref
*ref
=
3110 (struct buffer_ref
*)spd
->partial
[i
].private;
3115 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
3117 spd
->partial
[i
].private = 0;
3121 tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
3122 struct pipe_inode_info
*pipe
, size_t len
,
3125 struct ftrace_buffer_info
*info
= file
->private_data
;
3126 struct partial_page partial
[PIPE_BUFFERS
];
3127 struct page
*pages
[PIPE_BUFFERS
];
3128 struct splice_pipe_desc spd
= {
3132 .ops
= &buffer_pipe_buf_ops
,
3133 .spd_release
= buffer_spd_release
,
3135 struct buffer_ref
*ref
;
3140 * We can't seek on a buffer input
3142 if (unlikely(*ppos
))
3146 for (i
= 0; i
< PIPE_BUFFERS
&& len
; i
++, len
-= size
) {
3150 ref
= kzalloc(sizeof(*ref
), GFP_KERNEL
);
3154 ref
->buffer
= info
->tr
->buffer
;
3155 ref
->page
= ring_buffer_alloc_read_page(ref
->buffer
);
3161 r
= ring_buffer_read_page(ref
->buffer
, &ref
->page
,
3164 ring_buffer_free_read_page(ref
->buffer
,
3171 * zero out any left over data, this is going to
3174 size
= ring_buffer_page_len(ref
->page
);
3175 if (size
< PAGE_SIZE
)
3176 memset(ref
->page
+ size
, 0, PAGE_SIZE
- size
);
3178 page
= virt_to_page(ref
->page
);
3180 spd
.pages
[i
] = page
;
3181 spd
.partial
[i
].len
= PAGE_SIZE
;
3182 spd
.partial
[i
].offset
= 0;
3183 spd
.partial
[i
].private = (unsigned long)ref
;
3189 /* did we read anything? */
3190 if (!spd
.nr_pages
) {
3191 if (flags
& SPLICE_F_NONBLOCK
)
3199 ret
= splice_to_pipe(pipe
, &spd
);
3204 static const struct file_operations tracing_buffers_fops
= {
3205 .open
= tracing_buffers_open
,
3206 .read
= tracing_buffers_read
,
3207 .release
= tracing_buffers_release
,
3208 .splice_read
= tracing_buffers_splice_read
,
3209 .llseek
= no_llseek
,
3212 #ifdef CONFIG_DYNAMIC_FTRACE
3214 int __weak
ftrace_arch_read_dyn_info(char *buf
, int size
)
3220 tracing_read_dyn_info(struct file
*filp
, char __user
*ubuf
,
3221 size_t cnt
, loff_t
*ppos
)
3223 static char ftrace_dyn_info_buffer
[1024];
3224 static DEFINE_MUTEX(dyn_info_mutex
);
3225 unsigned long *p
= filp
->private_data
;
3226 char *buf
= ftrace_dyn_info_buffer
;
3227 int size
= ARRAY_SIZE(ftrace_dyn_info_buffer
);
3230 mutex_lock(&dyn_info_mutex
);
3231 r
= sprintf(buf
, "%ld ", *p
);
3233 r
+= ftrace_arch_read_dyn_info(buf
+r
, (size
-1)-r
);
3236 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3238 mutex_unlock(&dyn_info_mutex
);
3243 static struct file_operations tracing_dyn_info_fops
= {
3244 .open
= tracing_open_generic
,
3245 .read
= tracing_read_dyn_info
,
3249 static struct dentry
*d_tracer
;
3251 struct dentry
*tracing_init_dentry(void)
3258 d_tracer
= debugfs_create_dir("tracing", NULL
);
3260 if (!d_tracer
&& !once
) {
3262 pr_warning("Could not create debugfs directory 'tracing'\n");
3269 static struct dentry
*d_percpu
;
3271 struct dentry
*tracing_dentry_percpu(void)
3274 struct dentry
*d_tracer
;
3279 d_tracer
= tracing_init_dentry();
3284 d_percpu
= debugfs_create_dir("per_cpu", d_tracer
);
3286 if (!d_percpu
&& !once
) {
3288 pr_warning("Could not create debugfs directory 'per_cpu'\n");
3295 static void tracing_init_debugfs_percpu(long cpu
)
3297 struct dentry
*d_percpu
= tracing_dentry_percpu();
3298 struct dentry
*entry
, *d_cpu
;
3299 /* strlen(cpu) + MAX(log10(cpu)) + '\0' */
3302 if (cpu
> 999 || cpu
< 0)
3305 sprintf(cpu_dir
, "cpu%ld", cpu
);
3306 d_cpu
= debugfs_create_dir(cpu_dir
, d_percpu
);
3308 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir
);
3312 /* per cpu trace_pipe */
3313 entry
= debugfs_create_file("trace_pipe", 0444, d_cpu
,
3314 (void *) cpu
, &tracing_pipe_fops
);
3316 pr_warning("Could not create debugfs 'trace_pipe' entry\n");
3319 entry
= debugfs_create_file("trace", 0444, d_cpu
,
3320 (void *) cpu
, &tracing_fops
);
3322 pr_warning("Could not create debugfs 'trace' entry\n");
3325 #ifdef CONFIG_FTRACE_SELFTEST
3326 /* Let selftest have access to static functions in this file */
3327 #include "trace_selftest.c"
3330 struct trace_option_dentry
{
3331 struct tracer_opt
*opt
;
3332 struct tracer_flags
*flags
;
3333 struct dentry
*entry
;
3337 trace_options_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
3340 struct trace_option_dentry
*topt
= filp
->private_data
;
3343 if (topt
->flags
->val
& topt
->opt
->bit
)
3348 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
3352 trace_options_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
3355 struct trace_option_dentry
*topt
= filp
->private_data
;
3360 if (cnt
>= sizeof(buf
))
3363 if (copy_from_user(&buf
, ubuf
, cnt
))
3368 ret
= strict_strtoul(buf
, 10, &val
);
3375 /* do nothing if already cleared */
3376 if (!(topt
->flags
->val
& topt
->opt
->bit
))
3379 mutex_lock(&trace_types_lock
);
3380 if (current_trace
->set_flag
)
3381 ret
= current_trace
->set_flag(topt
->flags
->val
,
3383 mutex_unlock(&trace_types_lock
);
3386 topt
->flags
->val
&= ~topt
->opt
->bit
;
3389 /* do nothing if already set */
3390 if (topt
->flags
->val
& topt
->opt
->bit
)
3393 mutex_lock(&trace_types_lock
);
3394 if (current_trace
->set_flag
)
3395 ret
= current_trace
->set_flag(topt
->flags
->val
,
3397 mutex_unlock(&trace_types_lock
);
3400 topt
->flags
->val
|= topt
->opt
->bit
;
3413 static const struct file_operations trace_options_fops
= {
3414 .open
= tracing_open_generic
,
3415 .read
= trace_options_read
,
3416 .write
= trace_options_write
,
3420 trace_options_core_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
3423 long index
= (long)filp
->private_data
;
3426 if (trace_flags
& (1 << index
))
3431 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
3435 trace_options_core_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
3438 long index
= (long)filp
->private_data
;
3443 if (cnt
>= sizeof(buf
))
3446 if (copy_from_user(&buf
, ubuf
, cnt
))
3451 ret
= strict_strtoul(buf
, 10, &val
);
3457 trace_flags
&= ~(1 << index
);
3460 trace_flags
|= 1 << index
;
3472 static const struct file_operations trace_options_core_fops
= {
3473 .open
= tracing_open_generic
,
3474 .read
= trace_options_core_read
,
3475 .write
= trace_options_core_write
,
3478 static struct dentry
*trace_options_init_dentry(void)
3480 struct dentry
*d_tracer
;
3481 static struct dentry
*t_options
;
3486 d_tracer
= tracing_init_dentry();
3490 t_options
= debugfs_create_dir("options", d_tracer
);
3492 pr_warning("Could not create debugfs directory 'options'\n");
3500 create_trace_option_file(struct trace_option_dentry
*topt
,
3501 struct tracer_flags
*flags
,
3502 struct tracer_opt
*opt
)
3504 struct dentry
*t_options
;
3505 struct dentry
*entry
;
3507 t_options
= trace_options_init_dentry();
3511 topt
->flags
= flags
;
3514 entry
= debugfs_create_file(opt
->name
, 0644, t_options
, topt
,
3515 &trace_options_fops
);
3517 topt
->entry
= entry
;
3521 static struct trace_option_dentry
*
3522 create_trace_option_files(struct tracer
*tracer
)
3524 struct trace_option_dentry
*topts
;
3525 struct tracer_flags
*flags
;
3526 struct tracer_opt
*opts
;
3532 flags
= tracer
->flags
;
3534 if (!flags
|| !flags
->opts
)
3539 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
3542 topts
= kcalloc(cnt
+ 1, sizeof(*topts
), GFP_KERNEL
);
3546 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
3547 create_trace_option_file(&topts
[cnt
], flags
,
3554 destroy_trace_option_files(struct trace_option_dentry
*topts
)
3561 for (cnt
= 0; topts
[cnt
].opt
; cnt
++) {
3562 if (topts
[cnt
].entry
)
3563 debugfs_remove(topts
[cnt
].entry
);
3569 static struct dentry
*
3570 create_trace_option_core_file(const char *option
, long index
)
3572 struct dentry
*t_options
;
3573 struct dentry
*entry
;
3575 t_options
= trace_options_init_dentry();
3579 entry
= debugfs_create_file(option
, 0644, t_options
, (void *)index
,
3580 &trace_options_core_fops
);
3585 static __init
void create_trace_options_dir(void)
3587 struct dentry
*t_options
;
3588 struct dentry
*entry
;
3591 t_options
= trace_options_init_dentry();
3595 for (i
= 0; trace_options
[i
]; i
++) {
3596 entry
= create_trace_option_core_file(trace_options
[i
], i
);
3598 pr_warning("Could not create debugfs %s entry\n",
3603 static __init
int tracer_init_debugfs(void)
3605 struct dentry
*d_tracer
;
3606 struct dentry
*buffers
;
3607 struct dentry
*entry
;
3610 d_tracer
= tracing_init_dentry();
3612 entry
= debugfs_create_file("tracing_enabled", 0644, d_tracer
,
3613 &global_trace
, &tracing_ctrl_fops
);
3615 pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
3617 entry
= debugfs_create_file("trace_options", 0644, d_tracer
,
3618 NULL
, &tracing_iter_fops
);
3620 pr_warning("Could not create debugfs 'trace_options' entry\n");
3622 create_trace_options_dir();
3624 entry
= debugfs_create_file("tracing_cpumask", 0644, d_tracer
,
3625 NULL
, &tracing_cpumask_fops
);
3627 pr_warning("Could not create debugfs 'tracing_cpumask' entry\n");
3629 entry
= debugfs_create_file("trace", 0444, d_tracer
,
3630 (void *) TRACE_PIPE_ALL_CPU
, &tracing_fops
);
3632 pr_warning("Could not create debugfs 'trace' entry\n");
3634 entry
= debugfs_create_file("available_tracers", 0444, d_tracer
,
3635 &global_trace
, &show_traces_fops
);
3637 pr_warning("Could not create debugfs 'available_tracers' entry\n");
3639 entry
= debugfs_create_file("current_tracer", 0444, d_tracer
,
3640 &global_trace
, &set_tracer_fops
);
3642 pr_warning("Could not create debugfs 'current_tracer' entry\n");
3644 entry
= debugfs_create_file("tracing_max_latency", 0644, d_tracer
,
3645 &tracing_max_latency
,
3646 &tracing_max_lat_fops
);
3648 pr_warning("Could not create debugfs "
3649 "'tracing_max_latency' entry\n");
3651 entry
= debugfs_create_file("tracing_thresh", 0644, d_tracer
,
3652 &tracing_thresh
, &tracing_max_lat_fops
);
3654 pr_warning("Could not create debugfs "
3655 "'tracing_thresh' entry\n");
3656 entry
= debugfs_create_file("README", 0644, d_tracer
,
3657 NULL
, &tracing_readme_fops
);
3659 pr_warning("Could not create debugfs 'README' entry\n");
3661 entry
= debugfs_create_file("trace_pipe", 0444, d_tracer
,
3662 (void *) TRACE_PIPE_ALL_CPU
, &tracing_pipe_fops
);
3664 pr_warning("Could not create debugfs "
3665 "'trace_pipe' entry\n");
3667 entry
= debugfs_create_file("buffer_size_kb", 0644, d_tracer
,
3668 &global_trace
, &tracing_entries_fops
);
3670 pr_warning("Could not create debugfs "
3671 "'buffer_size_kb' entry\n");
3673 entry
= debugfs_create_file("trace_marker", 0220, d_tracer
,
3674 NULL
, &tracing_mark_fops
);
3676 pr_warning("Could not create debugfs "
3677 "'trace_marker' entry\n");
3679 buffers
= debugfs_create_dir("binary_buffers", d_tracer
);
3682 pr_warning("Could not create buffers directory\n");
3687 for_each_tracing_cpu(cpu
) {
3688 sprintf(buf
, "%d", cpu
);
3690 entry
= debugfs_create_file(buf
, 0444, buffers
,
3692 &tracing_buffers_fops
);
3694 pr_warning("Could not create debugfs buffers "
3695 "'%s' entry\n", buf
);
3699 #ifdef CONFIG_DYNAMIC_FTRACE
3700 entry
= debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
3701 &ftrace_update_tot_cnt
,
3702 &tracing_dyn_info_fops
);
3704 pr_warning("Could not create debugfs "
3705 "'dyn_ftrace_total_info' entry\n");
3707 #ifdef CONFIG_SYSPROF_TRACER
3708 init_tracer_sysprof_debugfs(d_tracer
);
3711 for_each_tracing_cpu(cpu
)
3712 tracing_init_debugfs_percpu(cpu
);
3717 int trace_vprintk(unsigned long ip
, int depth
, const char *fmt
, va_list args
)
3719 static raw_spinlock_t trace_buf_lock
= __RAW_SPIN_LOCK_UNLOCKED
;
3720 static char trace_buf
[TRACE_BUF_SIZE
];
3722 struct ring_buffer_event
*event
;
3723 struct trace_array
*tr
= &global_trace
;
3724 struct trace_array_cpu
*data
;
3725 int cpu
, len
= 0, size
, pc
;
3726 struct print_entry
*entry
;
3727 unsigned long irq_flags
;
3729 if (tracing_disabled
|| tracing_selftest_running
)
3732 pc
= preempt_count();
3733 preempt_disable_notrace();
3734 cpu
= raw_smp_processor_id();
3735 data
= tr
->data
[cpu
];
3737 if (unlikely(atomic_read(&data
->disabled
)))
3740 pause_graph_tracing();
3741 raw_local_irq_save(irq_flags
);
3742 __raw_spin_lock(&trace_buf_lock
);
3743 len
= vsnprintf(trace_buf
, TRACE_BUF_SIZE
, fmt
, args
);
3745 len
= min(len
, TRACE_BUF_SIZE
-1);
3748 size
= sizeof(*entry
) + len
+ 1;
3749 event
= trace_buffer_lock_reserve(tr
, TRACE_PRINT
, size
, irq_flags
, pc
);
3752 entry
= ring_buffer_event_data(event
);
3754 entry
->depth
= depth
;
3756 memcpy(&entry
->buf
, trace_buf
, len
);
3757 entry
->buf
[len
] = 0;
3758 ring_buffer_unlock_commit(tr
->buffer
, event
);
3761 __raw_spin_unlock(&trace_buf_lock
);
3762 raw_local_irq_restore(irq_flags
);
3763 unpause_graph_tracing();
3765 preempt_enable_notrace();
3769 EXPORT_SYMBOL_GPL(trace_vprintk
);
3771 int __ftrace_printk(unsigned long ip
, const char *fmt
, ...)
3776 if (!(trace_flags
& TRACE_ITER_PRINTK
))
3780 ret
= trace_vprintk(ip
, task_curr_ret_stack(current
), fmt
, ap
);
3784 EXPORT_SYMBOL_GPL(__ftrace_printk
);
3786 int __ftrace_vprintk(unsigned long ip
, const char *fmt
, va_list ap
)
3788 if (!(trace_flags
& TRACE_ITER_PRINTK
))
3791 return trace_vprintk(ip
, task_curr_ret_stack(current
), fmt
, ap
);
3793 EXPORT_SYMBOL_GPL(__ftrace_vprintk
);
3795 static int trace_panic_handler(struct notifier_block
*this,
3796 unsigned long event
, void *unused
)
3798 if (ftrace_dump_on_oops
)
3803 static struct notifier_block trace_panic_notifier
= {
3804 .notifier_call
= trace_panic_handler
,
3806 .priority
= 150 /* priority: INT_MAX >= x >= 0 */
3809 static int trace_die_handler(struct notifier_block
*self
,
3815 if (ftrace_dump_on_oops
)
3824 static struct notifier_block trace_die_notifier
= {
3825 .notifier_call
= trace_die_handler
,
3830 * printk is set to max of 1024, we really don't need it that big.
3831 * Nothing should be printing 1000 characters anyway.
3833 #define TRACE_MAX_PRINT 1000
3836 * Define here KERN_TRACE so that we have one place to modify
3837 * it if we decide to change what log level the ftrace dump
3840 #define KERN_TRACE KERN_EMERG
3843 trace_printk_seq(struct trace_seq
*s
)
3845 /* Probably should print a warning here. */
3849 /* should be zero ended, but we are paranoid. */
3850 s
->buffer
[s
->len
] = 0;
3852 printk(KERN_TRACE
"%s", s
->buffer
);
3857 void ftrace_dump(void)
3859 static DEFINE_SPINLOCK(ftrace_dump_lock
);
3860 /* use static because iter can be a bit big for the stack */
3861 static struct trace_iterator iter
;
3862 static int dump_ran
;
3863 unsigned long flags
;
3867 spin_lock_irqsave(&ftrace_dump_lock
, flags
);
3873 /* No turning back! */
3877 for_each_tracing_cpu(cpu
) {
3878 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
3881 /* don't look at user memory in panic mode */
3882 trace_flags
&= ~TRACE_ITER_SYM_USEROBJ
;
3884 printk(KERN_TRACE
"Dumping ftrace buffer:\n");
3886 /* Simulate the iterator */
3887 iter
.tr
= &global_trace
;
3888 iter
.trace
= current_trace
;
3889 iter
.cpu_file
= TRACE_PIPE_ALL_CPU
;
3892 * We need to stop all tracing on all CPUS to read the
3893 * the next buffer. This is a bit expensive, but is
3894 * not done often. We fill all what we can read,
3895 * and then release the locks again.
3898 while (!trace_empty(&iter
)) {
3901 printk(KERN_TRACE
"---------------------------------\n");
3905 /* reset all but tr, trace, and overruns */
3906 memset(&iter
.seq
, 0,
3907 sizeof(struct trace_iterator
) -
3908 offsetof(struct trace_iterator
, seq
));
3909 iter
.iter_flags
|= TRACE_FILE_LAT_FMT
;
3912 if (find_next_entry_inc(&iter
) != NULL
) {
3913 print_trace_line(&iter
);
3914 trace_consume(&iter
);
3917 trace_printk_seq(&iter
.seq
);
3921 printk(KERN_TRACE
" (ftrace buffer empty)\n");
3923 printk(KERN_TRACE
"---------------------------------\n");
3926 spin_unlock_irqrestore(&ftrace_dump_lock
, flags
);
3929 __init
static int tracer_alloc_buffers(void)
3931 struct trace_array_cpu
*data
;
3935 if (!alloc_cpumask_var(&tracing_buffer_mask
, GFP_KERNEL
))
3938 if (!alloc_cpumask_var(&tracing_cpumask
, GFP_KERNEL
))
3939 goto out_free_buffer_mask
;
3941 if (!alloc_cpumask_var(&tracing_reader_cpumask
, GFP_KERNEL
))
3942 goto out_free_tracing_cpumask
;
3944 cpumask_copy(tracing_buffer_mask
, cpu_possible_mask
);
3945 cpumask_copy(tracing_cpumask
, cpu_all_mask
);
3946 cpumask_clear(tracing_reader_cpumask
);
3948 /* TODO: make the number of buffers hot pluggable with CPUS */
3949 global_trace
.buffer
= ring_buffer_alloc(trace_buf_size
,
3950 TRACE_BUFFER_FLAGS
);
3951 if (!global_trace
.buffer
) {
3952 printk(KERN_ERR
"tracer: failed to allocate ring buffer!\n");
3954 goto out_free_cpumask
;
3956 global_trace
.entries
= ring_buffer_size(global_trace
.buffer
);
3959 #ifdef CONFIG_TRACER_MAX_TRACE
3960 max_tr
.buffer
= ring_buffer_alloc(trace_buf_size
,
3961 TRACE_BUFFER_FLAGS
);
3962 if (!max_tr
.buffer
) {
3963 printk(KERN_ERR
"tracer: failed to allocate max ring buffer!\n");
3965 ring_buffer_free(global_trace
.buffer
);
3966 goto out_free_cpumask
;
3968 max_tr
.entries
= ring_buffer_size(max_tr
.buffer
);
3969 WARN_ON(max_tr
.entries
!= global_trace
.entries
);
3972 /* Allocate the first page for all buffers */
3973 for_each_tracing_cpu(i
) {
3974 data
= global_trace
.data
[i
] = &per_cpu(global_trace_cpu
, i
);
3975 max_tr
.data
[i
] = &per_cpu(max_data
, i
);
3978 trace_init_cmdlines();
3980 register_tracer(&nop_trace
);
3981 current_trace
= &nop_trace
;
3982 #ifdef CONFIG_BOOT_TRACER
3983 register_tracer(&boot_tracer
);
3985 /* All seems OK, enable tracing */
3986 tracing_disabled
= 0;
3988 atomic_notifier_chain_register(&panic_notifier_list
,
3989 &trace_panic_notifier
);
3991 register_die_notifier(&trace_die_notifier
);
3995 free_cpumask_var(tracing_reader_cpumask
);
3996 out_free_tracing_cpumask
:
3997 free_cpumask_var(tracing_cpumask
);
3998 out_free_buffer_mask
:
3999 free_cpumask_var(tracing_buffer_mask
);
4004 __init
static int clear_boot_tracer(void)
4007 * The default tracer at boot buffer is an init section.
4008 * This function is called in lateinit. If we did not
4009 * find the boot tracer, then clear it out, to prevent
4010 * later registration from accessing the buffer that is
4011 * about to be freed.
4013 if (!default_bootup_tracer
)
4016 printk(KERN_INFO
"ftrace bootup tracer '%s' not registered.\n",
4017 default_bootup_tracer
);
4018 default_bootup_tracer
= NULL
;
4023 early_initcall(tracer_alloc_buffers
);
4024 fs_initcall(tracer_init_debugfs
);
4025 late_initcall(clear_boot_tracer
);