2 * ring buffer based function tracer
4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
7 * Originally taken from the RT patch by:
8 * Arnaldo Carvalho de Melo <acme@redhat.com>
10 * Based on code from the latency_tracer, that is:
11 * Copyright (C) 2004-2006 Ingo Molnar
12 * Copyright (C) 2004 William Lee Irwin III
14 #include <linux/ring_buffer.h>
15 #include <linux/utsrelease.h>
16 #include <linux/stacktrace.h>
17 #include <linux/writeback.h>
18 #include <linux/kallsyms.h>
19 #include <linux/seq_file.h>
20 #include <linux/notifier.h>
21 #include <linux/irqflags.h>
22 #include <linux/debugfs.h>
23 #include <linux/pagemap.h>
24 #include <linux/hardirq.h>
25 #include <linux/linkage.h>
26 #include <linux/uaccess.h>
27 #include <linux/kprobes.h>
28 #include <linux/ftrace.h>
29 #include <linux/module.h>
30 #include <linux/percpu.h>
31 #include <linux/splice.h>
32 #include <linux/kdebug.h>
33 #include <linux/ctype.h>
34 #include <linux/init.h>
35 #include <linux/poll.h>
36 #include <linux/gfp.h>
40 #include "trace_output.h"
42 #define TRACE_BUFFER_FLAGS (RB_FL_OVERWRITE)
44 unsigned long __read_mostly tracing_max_latency
;
45 unsigned long __read_mostly tracing_thresh
;
48 * On boot up, the ring buffer is set to the minimum size, so that
49 * we do not waste memory on systems that are not using tracing.
51 static int ring_buffer_expanded
;
54 * We need to change this state when a selftest is running.
55 * A selftest will lurk into the ring-buffer to count the
56 * entries inserted during the selftest although some concurrent
57 * insertions into the ring-buffer such as trace_printk could occurred
58 * at the same time, giving false positive or negative results.
60 static bool __read_mostly tracing_selftest_running
;
63 * If a tracer is running, we do not want to run SELFTEST.
65 static bool __read_mostly tracing_selftest_disabled
;
67 /* For tracers that don't implement custom flags */
68 static struct tracer_opt dummy_tracer_opt
[] = {
72 static struct tracer_flags dummy_tracer_flags
= {
74 .opts
= dummy_tracer_opt
77 static int dummy_set_flag(u32 old_flags
, u32 bit
, int set
)
83 * Kill all tracing for good (never come back).
84 * It is initialized to 1 but will turn to zero if the initialization
85 * of the tracer is successful. But that is the only place that sets
88 static int tracing_disabled
= 1;
90 static DEFINE_PER_CPU(local_t
, ftrace_cpu_disabled
);
92 static inline void ftrace_disable_cpu(void)
95 local_inc(&__get_cpu_var(ftrace_cpu_disabled
));
98 static inline void ftrace_enable_cpu(void)
100 local_dec(&__get_cpu_var(ftrace_cpu_disabled
));
104 static cpumask_var_t __read_mostly tracing_buffer_mask
;
106 /* Define which cpu buffers are currently read in trace_pipe */
107 static cpumask_var_t tracing_reader_cpumask
;
109 #define for_each_tracing_cpu(cpu) \
110 for_each_cpu(cpu, tracing_buffer_mask)
113 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
115 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
116 * is set, then ftrace_dump is called. This will output the contents
117 * of the ftrace buffers to the console. This is very useful for
118 * capturing traces that lead to crashes and outputing it to a
121 * It is default off, but you can enable it with either specifying
122 * "ftrace_dump_on_oops" in the kernel command line, or setting
123 * /proc/sys/kernel/ftrace_dump_on_oops to true.
125 int ftrace_dump_on_oops
;
127 static int tracing_set_tracer(const char *buf
);
129 #define BOOTUP_TRACER_SIZE 100
130 static char bootup_tracer_buf
[BOOTUP_TRACER_SIZE
] __initdata
;
131 static char *default_bootup_tracer
;
133 static int __init
set_ftrace(char *str
)
135 strncpy(bootup_tracer_buf
, str
, BOOTUP_TRACER_SIZE
);
136 default_bootup_tracer
= bootup_tracer_buf
;
137 /* We are using ftrace early, expand it */
138 ring_buffer_expanded
= 1;
141 __setup("ftrace=", set_ftrace
);
143 static int __init
set_ftrace_dump_on_oops(char *str
)
145 ftrace_dump_on_oops
= 1;
148 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops
);
151 ns2usecs(cycle_t nsec
)
158 cycle_t
ftrace_now(int cpu
)
160 u64 ts
= ring_buffer_time_stamp(cpu
);
161 ring_buffer_normalize_time_stamp(cpu
, &ts
);
166 * The global_trace is the descriptor that holds the tracing
167 * buffers for the live tracing. For each CPU, it contains
168 * a link list of pages that will store trace entries. The
169 * page descriptor of the pages in the memory is used to hold
170 * the link list by linking the lru item in the page descriptor
171 * to each of the pages in the buffer per CPU.
173 * For each active CPU there is a data field that holds the
174 * pages for the buffer for that CPU. Each CPU has the same number
175 * of pages allocated for its buffer.
177 static struct trace_array global_trace
;
179 static DEFINE_PER_CPU(struct trace_array_cpu
, global_trace_cpu
);
182 * The max_tr is used to snapshot the global_trace when a maximum
183 * latency is reached. Some tracers will use this to store a maximum
184 * trace while it continues examining live traces.
186 * The buffers for the max_tr are set up the same as the global_trace.
187 * When a snapshot is taken, the link list of the max_tr is swapped
188 * with the link list of the global_trace and the buffers are reset for
189 * the global_trace so the tracing can continue.
191 static struct trace_array max_tr
;
193 static DEFINE_PER_CPU(struct trace_array_cpu
, max_data
);
195 /* tracer_enabled is used to toggle activation of a tracer */
196 static int tracer_enabled
= 1;
199 * tracing_is_enabled - return tracer_enabled status
201 * This function is used by other tracers to know the status
202 * of the tracer_enabled flag. Tracers may use this function
203 * to know if it should enable their features when starting
204 * up. See irqsoff tracer for an example (start_irqsoff_tracer).
206 int tracing_is_enabled(void)
208 return tracer_enabled
;
212 * trace_buf_size is the size in bytes that is allocated
213 * for a buffer. Note, the number of bytes is always rounded
216 * This number is purposely set to a low number of 16384.
217 * If the dump on oops happens, it will be much appreciated
218 * to not have to wait for all that output. Anyway this can be
219 * boot time and run time configurable.
221 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
223 static unsigned long trace_buf_size
= TRACE_BUF_SIZE_DEFAULT
;
225 /* trace_types holds a link list of available tracers. */
226 static struct tracer
*trace_types __read_mostly
;
228 /* current_trace points to the tracer that is currently active */
229 static struct tracer
*current_trace __read_mostly
;
232 * max_tracer_type_len is used to simplify the allocating of
233 * buffers to read userspace tracer names. We keep track of
234 * the longest tracer name registered.
236 static int max_tracer_type_len
;
239 * trace_types_lock is used to protect the trace_types list.
240 * This lock is also used to keep user access serialized.
241 * Accesses from userspace will grab this lock while userspace
242 * activities happen inside the kernel.
244 static DEFINE_MUTEX(trace_types_lock
);
246 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
247 static DECLARE_WAIT_QUEUE_HEAD(trace_wait
);
249 /* trace_flags holds trace_options default values */
250 unsigned long trace_flags
= TRACE_ITER_PRINT_PARENT
| TRACE_ITER_PRINTK
|
251 TRACE_ITER_ANNOTATE
| TRACE_ITER_CONTEXT_INFO
;
254 * trace_wake_up - wake up tasks waiting for trace input
256 * Simply wakes up any task that is blocked on the trace_wait
257 * queue. These is used with trace_poll for tasks polling the trace.
259 void trace_wake_up(void)
262 * The runqueue_is_locked() can fail, but this is the best we
265 if (!(trace_flags
& TRACE_ITER_BLOCK
) && !runqueue_is_locked())
266 wake_up(&trace_wait
);
269 static int __init
set_buf_size(char *str
)
271 unsigned long buf_size
;
276 ret
= strict_strtoul(str
, 0, &buf_size
);
277 /* nr_entries can not be zero */
278 if (ret
< 0 || buf_size
== 0)
280 trace_buf_size
= buf_size
;
283 __setup("trace_buf_size=", set_buf_size
);
285 unsigned long nsecs_to_usecs(unsigned long nsecs
)
290 /* These must match the bit postions in trace_iterator_flags */
291 static const char *trace_options
[] = {
315 * ftrace_max_lock is used to protect the swapping of buffers
316 * when taking a max snapshot. The buffers themselves are
317 * protected by per_cpu spinlocks. But the action of the swap
318 * needs its own lock.
320 * This is defined as a raw_spinlock_t in order to help
321 * with performance when lockdep debugging is enabled.
323 static raw_spinlock_t ftrace_max_lock
=
324 (raw_spinlock_t
)__RAW_SPIN_LOCK_UNLOCKED
;
327 * Copy the new maximum trace into the separate maximum-trace
328 * structure. (this way the maximum trace is permanently saved,
329 * for later retrieval via /debugfs/tracing/latency_trace)
332 __update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
334 struct trace_array_cpu
*data
= tr
->data
[cpu
];
337 max_tr
.time_start
= data
->preempt_timestamp
;
339 data
= max_tr
.data
[cpu
];
340 data
->saved_latency
= tracing_max_latency
;
342 memcpy(data
->comm
, tsk
->comm
, TASK_COMM_LEN
);
343 data
->pid
= tsk
->pid
;
344 data
->uid
= task_uid(tsk
);
345 data
->nice
= tsk
->static_prio
- 20 - MAX_RT_PRIO
;
346 data
->policy
= tsk
->policy
;
347 data
->rt_priority
= tsk
->rt_priority
;
349 /* record this tasks comm */
350 tracing_record_cmdline(tsk
);
353 ssize_t
trace_seq_to_user(struct trace_seq
*s
, char __user
*ubuf
, size_t cnt
)
361 if (s
->len
<= s
->readpos
)
364 len
= s
->len
- s
->readpos
;
367 ret
= copy_to_user(ubuf
, s
->buffer
+ s
->readpos
, cnt
);
377 ssize_t
trace_seq_to_buffer(struct trace_seq
*s
, void *buf
, size_t cnt
)
382 if (s
->len
<= s
->readpos
)
385 len
= s
->len
- s
->readpos
;
388 ret
= memcpy(buf
, s
->buffer
+ s
->readpos
, cnt
);
397 trace_print_seq(struct seq_file
*m
, struct trace_seq
*s
)
399 int len
= s
->len
>= PAGE_SIZE
? PAGE_SIZE
- 1 : s
->len
;
402 seq_puts(m
, s
->buffer
);
408 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
410 * @tsk: the task with the latency
411 * @cpu: The cpu that initiated the trace.
413 * Flip the buffers between the @tr and the max_tr and record information
414 * about which task was the cause of this latency.
417 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
419 struct ring_buffer
*buf
= tr
->buffer
;
421 WARN_ON_ONCE(!irqs_disabled());
422 __raw_spin_lock(&ftrace_max_lock
);
424 tr
->buffer
= max_tr
.buffer
;
427 ftrace_disable_cpu();
428 ring_buffer_reset(tr
->buffer
);
431 __update_max_tr(tr
, tsk
, cpu
);
432 __raw_spin_unlock(&ftrace_max_lock
);
436 * update_max_tr_single - only copy one trace over, and reset the rest
438 * @tsk - task with the latency
439 * @cpu - the cpu of the buffer to copy.
441 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
444 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
448 WARN_ON_ONCE(!irqs_disabled());
449 __raw_spin_lock(&ftrace_max_lock
);
451 ftrace_disable_cpu();
453 ring_buffer_reset(max_tr
.buffer
);
454 ret
= ring_buffer_swap_cpu(max_tr
.buffer
, tr
->buffer
, cpu
);
458 WARN_ON_ONCE(ret
&& ret
!= -EAGAIN
);
460 __update_max_tr(tr
, tsk
, cpu
);
461 __raw_spin_unlock(&ftrace_max_lock
);
465 * register_tracer - register a tracer with the ftrace system.
466 * @type - the plugin for the tracer
468 * Register a new plugin tracer.
470 int register_tracer(struct tracer
*type
)
471 __releases(kernel_lock
)
472 __acquires(kernel_lock
)
479 pr_info("Tracer must have a name\n");
484 * When this gets called we hold the BKL which means that
485 * preemption is disabled. Various trace selftests however
486 * need to disable and enable preemption for successful tests.
487 * So we drop the BKL here and grab it after the tests again.
490 mutex_lock(&trace_types_lock
);
492 tracing_selftest_running
= true;
494 for (t
= trace_types
; t
; t
= t
->next
) {
495 if (strcmp(type
->name
, t
->name
) == 0) {
497 pr_info("Trace %s already registered\n",
505 type
->set_flag
= &dummy_set_flag
;
507 type
->flags
= &dummy_tracer_flags
;
509 if (!type
->flags
->opts
)
510 type
->flags
->opts
= dummy_tracer_opt
;
511 if (!type
->wait_pipe
)
512 type
->wait_pipe
= default_wait_pipe
;
515 #ifdef CONFIG_FTRACE_STARTUP_TEST
516 if (type
->selftest
&& !tracing_selftest_disabled
) {
517 struct tracer
*saved_tracer
= current_trace
;
518 struct trace_array
*tr
= &global_trace
;
522 * Run a selftest on this tracer.
523 * Here we reset the trace buffer, and set the current
524 * tracer to be this tracer. The tracer can then run some
525 * internal tracing to verify that everything is in order.
526 * If we fail, we do not register this tracer.
528 for_each_tracing_cpu(i
)
529 tracing_reset(tr
, i
);
531 current_trace
= type
;
532 /* the test is responsible for initializing and enabling */
533 pr_info("Testing tracer %s: ", type
->name
);
534 ret
= type
->selftest(type
, tr
);
535 /* the test is responsible for resetting too */
536 current_trace
= saved_tracer
;
538 printk(KERN_CONT
"FAILED!\n");
541 /* Only reset on passing, to avoid touching corrupted buffers */
542 for_each_tracing_cpu(i
)
543 tracing_reset(tr
, i
);
545 printk(KERN_CONT
"PASSED\n");
549 type
->next
= trace_types
;
551 len
= strlen(type
->name
);
552 if (len
> max_tracer_type_len
)
553 max_tracer_type_len
= len
;
556 tracing_selftest_running
= false;
557 mutex_unlock(&trace_types_lock
);
559 if (ret
|| !default_bootup_tracer
)
562 if (strncmp(default_bootup_tracer
, type
->name
, BOOTUP_TRACER_SIZE
))
565 printk(KERN_INFO
"Starting tracer '%s'\n", type
->name
);
566 /* Do we want this tracer to start on bootup? */
567 tracing_set_tracer(type
->name
);
568 default_bootup_tracer
= NULL
;
569 /* disable other selftests, since this will break it. */
570 tracing_selftest_disabled
= 1;
571 #ifdef CONFIG_FTRACE_STARTUP_TEST
572 printk(KERN_INFO
"Disabling FTRACE selftests due to running tracer '%s'\n",
581 void unregister_tracer(struct tracer
*type
)
586 mutex_lock(&trace_types_lock
);
587 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
591 pr_info("Trace %s not registered\n", type
->name
);
597 if (type
== current_trace
&& tracer_enabled
) {
600 if (current_trace
->stop
)
601 current_trace
->stop(&global_trace
);
602 current_trace
= &nop_trace
;
605 if (strlen(type
->name
) != max_tracer_type_len
)
608 max_tracer_type_len
= 0;
609 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
610 len
= strlen((*t
)->name
);
611 if (len
> max_tracer_type_len
)
612 max_tracer_type_len
= len
;
615 mutex_unlock(&trace_types_lock
);
618 void tracing_reset(struct trace_array
*tr
, int cpu
)
620 ftrace_disable_cpu();
621 ring_buffer_reset_cpu(tr
->buffer
, cpu
);
625 void tracing_reset_online_cpus(struct trace_array
*tr
)
629 tr
->time_start
= ftrace_now(tr
->cpu
);
631 for_each_online_cpu(cpu
)
632 tracing_reset(tr
, cpu
);
635 #define SAVED_CMDLINES 128
636 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
637 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
638 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
639 static int cmdline_idx
;
640 static raw_spinlock_t trace_cmdline_lock
= __RAW_SPIN_LOCK_UNLOCKED
;
642 /* temporary disable recording */
643 static atomic_t trace_record_cmdline_disabled __read_mostly
;
645 static void trace_init_cmdlines(void)
647 memset(&map_pid_to_cmdline
, -1, sizeof(map_pid_to_cmdline
));
648 memset(&map_cmdline_to_pid
, -1, sizeof(map_cmdline_to_pid
));
652 static int trace_stop_count
;
653 static DEFINE_SPINLOCK(tracing_start_lock
);
656 * ftrace_off_permanent - disable all ftrace code permanently
658 * This should only be called when a serious anomally has
659 * been detected. This will turn off the function tracing,
660 * ring buffers, and other tracing utilites. It takes no
661 * locks and can be called from any context.
663 void ftrace_off_permanent(void)
665 tracing_disabled
= 1;
667 tracing_off_permanent();
671 * tracing_start - quick start of the tracer
673 * If tracing is enabled but was stopped by tracing_stop,
674 * this will start the tracer back up.
676 void tracing_start(void)
678 struct ring_buffer
*buffer
;
681 if (tracing_disabled
)
684 spin_lock_irqsave(&tracing_start_lock
, flags
);
685 if (--trace_stop_count
) {
686 if (trace_stop_count
< 0) {
687 /* Someone screwed up their debugging */
689 trace_stop_count
= 0;
695 buffer
= global_trace
.buffer
;
697 ring_buffer_record_enable(buffer
);
699 buffer
= max_tr
.buffer
;
701 ring_buffer_record_enable(buffer
);
705 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
709 * tracing_stop - quick stop of the tracer
711 * Light weight way to stop tracing. Use in conjunction with
714 void tracing_stop(void)
716 struct ring_buffer
*buffer
;
720 spin_lock_irqsave(&tracing_start_lock
, flags
);
721 if (trace_stop_count
++)
724 buffer
= global_trace
.buffer
;
726 ring_buffer_record_disable(buffer
);
728 buffer
= max_tr
.buffer
;
730 ring_buffer_record_disable(buffer
);
733 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
736 void trace_stop_cmdline_recording(void);
738 static void trace_save_cmdline(struct task_struct
*tsk
)
743 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
747 * It's not the end of the world if we don't get
748 * the lock, but we also don't want to spin
749 * nor do we want to disable interrupts,
750 * so if we miss here, then better luck next time.
752 if (!__raw_spin_trylock(&trace_cmdline_lock
))
755 idx
= map_pid_to_cmdline
[tsk
->pid
];
756 if (idx
>= SAVED_CMDLINES
) {
757 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
759 map
= map_cmdline_to_pid
[idx
];
760 if (map
<= PID_MAX_DEFAULT
)
761 map_pid_to_cmdline
[map
] = (unsigned)-1;
763 map_pid_to_cmdline
[tsk
->pid
] = idx
;
768 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
770 __raw_spin_unlock(&trace_cmdline_lock
);
773 char *trace_find_cmdline(int pid
)
775 char *cmdline
= "<...>";
781 if (pid
> PID_MAX_DEFAULT
)
784 map
= map_pid_to_cmdline
[pid
];
785 if (map
>= SAVED_CMDLINES
)
788 cmdline
= saved_cmdlines
[map
];
794 void tracing_record_cmdline(struct task_struct
*tsk
)
796 if (atomic_read(&trace_record_cmdline_disabled
))
799 trace_save_cmdline(tsk
);
803 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
,
806 struct task_struct
*tsk
= current
;
808 entry
->preempt_count
= pc
& 0xff;
809 entry
->pid
= (tsk
) ? tsk
->pid
: 0;
810 entry
->tgid
= (tsk
) ? tsk
->tgid
: 0;
812 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
813 (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
815 TRACE_FLAG_IRQS_NOSUPPORT
|
817 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
818 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
819 (need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0);
822 struct ring_buffer_event
*trace_buffer_lock_reserve(struct trace_array
*tr
,
825 unsigned long flags
, int pc
)
827 struct ring_buffer_event
*event
;
829 event
= ring_buffer_lock_reserve(tr
->buffer
, len
);
831 struct trace_entry
*ent
= ring_buffer_event_data(event
);
833 tracing_generic_entry_update(ent
, flags
, pc
);
839 static void ftrace_trace_stack(struct trace_array
*tr
,
840 unsigned long flags
, int skip
, int pc
);
841 static void ftrace_trace_userstack(struct trace_array
*tr
,
842 unsigned long flags
, int pc
);
844 void trace_buffer_unlock_commit(struct trace_array
*tr
,
845 struct ring_buffer_event
*event
,
846 unsigned long flags
, int pc
)
848 ring_buffer_unlock_commit(tr
->buffer
, event
);
850 ftrace_trace_stack(tr
, flags
, 6, pc
);
851 ftrace_trace_userstack(tr
, flags
, pc
);
855 struct ring_buffer_event
*
856 trace_current_buffer_lock_reserve(unsigned char type
, unsigned long len
,
857 unsigned long flags
, int pc
)
859 return trace_buffer_lock_reserve(&global_trace
,
860 type
, len
, flags
, pc
);
863 void trace_current_buffer_unlock_commit(struct ring_buffer_event
*event
,
864 unsigned long flags
, int pc
)
866 return trace_buffer_unlock_commit(&global_trace
, event
, flags
, pc
);
870 trace_function(struct trace_array
*tr
,
871 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
874 struct ring_buffer_event
*event
;
875 struct ftrace_entry
*entry
;
877 /* If we are reading the ring buffer, don't trace */
878 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
881 event
= trace_buffer_lock_reserve(tr
, TRACE_FN
, sizeof(*entry
),
885 entry
= ring_buffer_event_data(event
);
887 entry
->parent_ip
= parent_ip
;
888 ring_buffer_unlock_commit(tr
->buffer
, event
);
891 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
892 static void __trace_graph_entry(struct trace_array
*tr
,
893 struct ftrace_graph_ent
*trace
,
897 struct ring_buffer_event
*event
;
898 struct ftrace_graph_ent_entry
*entry
;
900 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
903 event
= trace_buffer_lock_reserve(&global_trace
, TRACE_GRAPH_ENT
,
904 sizeof(*entry
), flags
, pc
);
907 entry
= ring_buffer_event_data(event
);
908 entry
->graph_ent
= *trace
;
909 ring_buffer_unlock_commit(global_trace
.buffer
, event
);
912 static void __trace_graph_return(struct trace_array
*tr
,
913 struct ftrace_graph_ret
*trace
,
917 struct ring_buffer_event
*event
;
918 struct ftrace_graph_ret_entry
*entry
;
920 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
923 event
= trace_buffer_lock_reserve(&global_trace
, TRACE_GRAPH_RET
,
924 sizeof(*entry
), flags
, pc
);
927 entry
= ring_buffer_event_data(event
);
929 ring_buffer_unlock_commit(global_trace
.buffer
, event
);
934 ftrace(struct trace_array
*tr
, struct trace_array_cpu
*data
,
935 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
938 if (likely(!atomic_read(&data
->disabled
)))
939 trace_function(tr
, ip
, parent_ip
, flags
, pc
);
942 static void __ftrace_trace_stack(struct trace_array
*tr
,
946 #ifdef CONFIG_STACKTRACE
947 struct ring_buffer_event
*event
;
948 struct stack_entry
*entry
;
949 struct stack_trace trace
;
951 event
= trace_buffer_lock_reserve(tr
, TRACE_STACK
,
952 sizeof(*entry
), flags
, pc
);
955 entry
= ring_buffer_event_data(event
);
956 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
958 trace
.nr_entries
= 0;
959 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
961 trace
.entries
= entry
->caller
;
963 save_stack_trace(&trace
);
964 ring_buffer_unlock_commit(tr
->buffer
, event
);
968 static void ftrace_trace_stack(struct trace_array
*tr
,
972 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
975 __ftrace_trace_stack(tr
, flags
, skip
, pc
);
978 void __trace_stack(struct trace_array
*tr
,
982 __ftrace_trace_stack(tr
, flags
, skip
, pc
);
985 static void ftrace_trace_userstack(struct trace_array
*tr
,
986 unsigned long flags
, int pc
)
988 #ifdef CONFIG_STACKTRACE
989 struct ring_buffer_event
*event
;
990 struct userstack_entry
*entry
;
991 struct stack_trace trace
;
993 if (!(trace_flags
& TRACE_ITER_USERSTACKTRACE
))
996 event
= trace_buffer_lock_reserve(tr
, TRACE_USER_STACK
,
997 sizeof(*entry
), flags
, pc
);
1000 entry
= ring_buffer_event_data(event
);
1002 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
1004 trace
.nr_entries
= 0;
1005 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1007 trace
.entries
= entry
->caller
;
1009 save_stack_trace_user(&trace
);
1010 ring_buffer_unlock_commit(tr
->buffer
, event
);
1015 static void __trace_userstack(struct trace_array
*tr
, unsigned long flags
)
1017 ftrace_trace_userstack(tr
, flags
, preempt_count());
1022 ftrace_trace_special(void *__tr
,
1023 unsigned long arg1
, unsigned long arg2
, unsigned long arg3
,
1026 struct ring_buffer_event
*event
;
1027 struct trace_array
*tr
= __tr
;
1028 struct special_entry
*entry
;
1030 event
= trace_buffer_lock_reserve(tr
, TRACE_SPECIAL
,
1031 sizeof(*entry
), 0, pc
);
1034 entry
= ring_buffer_event_data(event
);
1038 trace_buffer_unlock_commit(tr
, event
, 0, pc
);
1042 __trace_special(void *__tr
, void *__data
,
1043 unsigned long arg1
, unsigned long arg2
, unsigned long arg3
)
1045 ftrace_trace_special(__tr
, arg1
, arg2
, arg3
, preempt_count());
1049 tracing_sched_switch_trace(struct trace_array
*tr
,
1050 struct task_struct
*prev
,
1051 struct task_struct
*next
,
1052 unsigned long flags
, int pc
)
1054 struct ring_buffer_event
*event
;
1055 struct ctx_switch_entry
*entry
;
1057 event
= trace_buffer_lock_reserve(tr
, TRACE_CTX
,
1058 sizeof(*entry
), flags
, pc
);
1061 entry
= ring_buffer_event_data(event
);
1062 entry
->prev_pid
= prev
->pid
;
1063 entry
->prev_prio
= prev
->prio
;
1064 entry
->prev_state
= prev
->state
;
1065 entry
->next_pid
= next
->pid
;
1066 entry
->next_prio
= next
->prio
;
1067 entry
->next_state
= next
->state
;
1068 entry
->next_cpu
= task_cpu(next
);
1069 trace_buffer_unlock_commit(tr
, event
, flags
, pc
);
1073 tracing_sched_wakeup_trace(struct trace_array
*tr
,
1074 struct task_struct
*wakee
,
1075 struct task_struct
*curr
,
1076 unsigned long flags
, int pc
)
1078 struct ring_buffer_event
*event
;
1079 struct ctx_switch_entry
*entry
;
1081 event
= trace_buffer_lock_reserve(tr
, TRACE_WAKE
,
1082 sizeof(*entry
), flags
, pc
);
1085 entry
= ring_buffer_event_data(event
);
1086 entry
->prev_pid
= curr
->pid
;
1087 entry
->prev_prio
= curr
->prio
;
1088 entry
->prev_state
= curr
->state
;
1089 entry
->next_pid
= wakee
->pid
;
1090 entry
->next_prio
= wakee
->prio
;
1091 entry
->next_state
= wakee
->state
;
1092 entry
->next_cpu
= task_cpu(wakee
);
1094 ring_buffer_unlock_commit(tr
->buffer
, event
);
1095 ftrace_trace_stack(tr
, flags
, 6, pc
);
1096 ftrace_trace_userstack(tr
, flags
, pc
);
1100 ftrace_special(unsigned long arg1
, unsigned long arg2
, unsigned long arg3
)
1102 struct trace_array
*tr
= &global_trace
;
1103 struct trace_array_cpu
*data
;
1104 unsigned long flags
;
1108 if (tracing_disabled
)
1111 pc
= preempt_count();
1112 local_irq_save(flags
);
1113 cpu
= raw_smp_processor_id();
1114 data
= tr
->data
[cpu
];
1116 if (likely(atomic_inc_return(&data
->disabled
) == 1))
1117 ftrace_trace_special(tr
, arg1
, arg2
, arg3
, pc
);
1119 atomic_dec(&data
->disabled
);
1120 local_irq_restore(flags
);
1123 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1124 int trace_graph_entry(struct ftrace_graph_ent
*trace
)
1126 struct trace_array
*tr
= &global_trace
;
1127 struct trace_array_cpu
*data
;
1128 unsigned long flags
;
1133 if (!ftrace_trace_task(current
))
1136 if (!ftrace_graph_addr(trace
->func
))
1139 local_irq_save(flags
);
1140 cpu
= raw_smp_processor_id();
1141 data
= tr
->data
[cpu
];
1142 disabled
= atomic_inc_return(&data
->disabled
);
1143 if (likely(disabled
== 1)) {
1144 pc
= preempt_count();
1145 __trace_graph_entry(tr
, trace
, flags
, pc
);
1147 /* Only do the atomic if it is not already set */
1148 if (!test_tsk_trace_graph(current
))
1149 set_tsk_trace_graph(current
);
1150 atomic_dec(&data
->disabled
);
1151 local_irq_restore(flags
);
1156 void trace_graph_return(struct ftrace_graph_ret
*trace
)
1158 struct trace_array
*tr
= &global_trace
;
1159 struct trace_array_cpu
*data
;
1160 unsigned long flags
;
1165 local_irq_save(flags
);
1166 cpu
= raw_smp_processor_id();
1167 data
= tr
->data
[cpu
];
1168 disabled
= atomic_inc_return(&data
->disabled
);
1169 if (likely(disabled
== 1)) {
1170 pc
= preempt_count();
1171 __trace_graph_return(tr
, trace
, flags
, pc
);
1174 clear_tsk_trace_graph(current
);
1175 atomic_dec(&data
->disabled
);
1176 local_irq_restore(flags
);
1178 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1182 * trace_vprintk - write binary msg to tracing buffer
1185 int trace_vprintk(unsigned long ip
, int depth
, const char *fmt
, va_list args
)
1187 static raw_spinlock_t trace_buf_lock
=
1188 (raw_spinlock_t
)__RAW_SPIN_LOCK_UNLOCKED
;
1189 static u32 trace_buf
[TRACE_BUF_SIZE
];
1191 struct ring_buffer_event
*event
;
1192 struct trace_array
*tr
= &global_trace
;
1193 struct trace_array_cpu
*data
;
1194 struct print_entry
*entry
;
1195 unsigned long flags
;
1197 int cpu
, len
= 0, size
, pc
;
1199 if (unlikely(tracing_selftest_running
|| tracing_disabled
))
1202 /* Don't pollute graph traces with trace_vprintk internals */
1203 pause_graph_tracing();
1205 pc
= preempt_count();
1206 resched
= ftrace_preempt_disable();
1207 cpu
= raw_smp_processor_id();
1208 data
= tr
->data
[cpu
];
1210 if (unlikely(atomic_read(&data
->disabled
)))
1213 /* Lockdep uses trace_printk for lock tracing */
1214 local_irq_save(flags
);
1215 __raw_spin_lock(&trace_buf_lock
);
1216 len
= vbin_printf(trace_buf
, TRACE_BUF_SIZE
, fmt
, args
);
1218 if (len
> TRACE_BUF_SIZE
|| len
< 0)
1221 size
= sizeof(*entry
) + sizeof(u32
) * len
;
1222 event
= trace_buffer_lock_reserve(tr
, TRACE_PRINT
, size
, flags
, pc
);
1225 entry
= ring_buffer_event_data(event
);
1227 entry
->depth
= depth
;
1230 memcpy(entry
->buf
, trace_buf
, sizeof(u32
) * len
);
1231 ring_buffer_unlock_commit(tr
->buffer
, event
);
1234 __raw_spin_unlock(&trace_buf_lock
);
1235 local_irq_restore(flags
);
1238 ftrace_preempt_enable(resched
);
1239 unpause_graph_tracing();
1243 EXPORT_SYMBOL_GPL(trace_vprintk
);
1245 enum trace_file_type
{
1246 TRACE_FILE_LAT_FMT
= 1,
1247 TRACE_FILE_ANNOTATE
= 2,
1250 static void trace_iterator_increment(struct trace_iterator
*iter
)
1252 /* Don't allow ftrace to trace into the ring buffers */
1253 ftrace_disable_cpu();
1256 if (iter
->buffer_iter
[iter
->cpu
])
1257 ring_buffer_read(iter
->buffer_iter
[iter
->cpu
], NULL
);
1259 ftrace_enable_cpu();
1262 static struct trace_entry
*
1263 peek_next_entry(struct trace_iterator
*iter
, int cpu
, u64
*ts
)
1265 struct ring_buffer_event
*event
;
1266 struct ring_buffer_iter
*buf_iter
= iter
->buffer_iter
[cpu
];
1268 /* Don't allow ftrace to trace into the ring buffers */
1269 ftrace_disable_cpu();
1272 event
= ring_buffer_iter_peek(buf_iter
, ts
);
1274 event
= ring_buffer_peek(iter
->tr
->buffer
, cpu
, ts
);
1276 ftrace_enable_cpu();
1278 return event
? ring_buffer_event_data(event
) : NULL
;
1281 static struct trace_entry
*
1282 __find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
, u64
*ent_ts
)
1284 struct ring_buffer
*buffer
= iter
->tr
->buffer
;
1285 struct trace_entry
*ent
, *next
= NULL
;
1286 int cpu_file
= iter
->cpu_file
;
1287 u64 next_ts
= 0, ts
;
1292 * If we are in a per_cpu trace file, don't bother by iterating over
1293 * all cpu and peek directly.
1295 if (cpu_file
> TRACE_PIPE_ALL_CPU
) {
1296 if (ring_buffer_empty_cpu(buffer
, cpu_file
))
1298 ent
= peek_next_entry(iter
, cpu_file
, ent_ts
);
1300 *ent_cpu
= cpu_file
;
1305 for_each_tracing_cpu(cpu
) {
1307 if (ring_buffer_empty_cpu(buffer
, cpu
))
1310 ent
= peek_next_entry(iter
, cpu
, &ts
);
1313 * Pick the entry with the smallest timestamp:
1315 if (ent
&& (!next
|| ts
< next_ts
)) {
1323 *ent_cpu
= next_cpu
;
1331 /* Find the next real entry, without updating the iterator itself */
1332 struct trace_entry
*trace_find_next_entry(struct trace_iterator
*iter
,
1333 int *ent_cpu
, u64
*ent_ts
)
1335 return __find_next_entry(iter
, ent_cpu
, ent_ts
);
1338 /* Find the next real entry, and increment the iterator to the next entry */
1339 static void *find_next_entry_inc(struct trace_iterator
*iter
)
1341 iter
->ent
= __find_next_entry(iter
, &iter
->cpu
, &iter
->ts
);
1344 trace_iterator_increment(iter
);
1346 return iter
->ent
? iter
: NULL
;
1349 static void trace_consume(struct trace_iterator
*iter
)
1351 /* Don't allow ftrace to trace into the ring buffers */
1352 ftrace_disable_cpu();
1353 ring_buffer_consume(iter
->tr
->buffer
, iter
->cpu
, &iter
->ts
);
1354 ftrace_enable_cpu();
1357 static void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1359 struct trace_iterator
*iter
= m
->private;
1365 /* can't go backwards */
1370 ent
= find_next_entry_inc(iter
);
1374 while (ent
&& iter
->idx
< i
)
1375 ent
= find_next_entry_inc(iter
);
1383 * No necessary locking here. The worst thing which can
1384 * happen is loosing events consumed at the same time
1385 * by a trace_pipe reader.
1386 * Other than that, we don't risk to crash the ring buffer
1387 * because it serializes the readers.
1389 * The current tracer is copied to avoid a global locking
1392 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
1394 struct trace_iterator
*iter
= m
->private;
1395 static struct tracer
*old_tracer
;
1396 int cpu_file
= iter
->cpu_file
;
1401 /* copy the tracer to avoid using a global lock all around */
1402 mutex_lock(&trace_types_lock
);
1403 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
1404 old_tracer
= current_trace
;
1405 *iter
->trace
= *current_trace
;
1407 mutex_unlock(&trace_types_lock
);
1409 atomic_inc(&trace_record_cmdline_disabled
);
1411 if (*pos
!= iter
->pos
) {
1416 ftrace_disable_cpu();
1418 if (cpu_file
== TRACE_PIPE_ALL_CPU
) {
1419 for_each_tracing_cpu(cpu
)
1420 ring_buffer_iter_reset(iter
->buffer_iter
[cpu
]);
1422 ring_buffer_iter_reset(iter
->buffer_iter
[cpu_file
]);
1425 ftrace_enable_cpu();
1427 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
1432 p
= s_next(m
, p
, &l
);
1438 static void s_stop(struct seq_file
*m
, void *p
)
1440 atomic_dec(&trace_record_cmdline_disabled
);
1443 static void print_lat_help_header(struct seq_file
*m
)
1445 seq_puts(m
, "# _------=> CPU# \n");
1446 seq_puts(m
, "# / _-----=> irqs-off \n");
1447 seq_puts(m
, "# | / _----=> need-resched \n");
1448 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
1449 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
1450 seq_puts(m
, "# |||| / \n");
1451 seq_puts(m
, "# ||||| delay \n");
1452 seq_puts(m
, "# cmd pid ||||| time | caller \n");
1453 seq_puts(m
, "# \\ / ||||| \\ | / \n");
1456 static void print_func_help_header(struct seq_file
*m
)
1458 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1459 seq_puts(m
, "# | | | | |\n");
1464 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
1466 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1467 struct trace_array
*tr
= iter
->tr
;
1468 struct trace_array_cpu
*data
= tr
->data
[tr
->cpu
];
1469 struct tracer
*type
= current_trace
;
1470 unsigned long total
;
1471 unsigned long entries
;
1472 const char *name
= "preemption";
1477 entries
= ring_buffer_entries(iter
->tr
->buffer
);
1479 ring_buffer_overruns(iter
->tr
->buffer
);
1481 seq_printf(m
, "# %s latency trace v1.1.5 on %s\n",
1483 seq_puts(m
, "# -----------------------------------"
1484 "---------------------------------\n");
1485 seq_printf(m
, "# latency: %lu us, #%lu/%lu, CPU#%d |"
1486 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1487 nsecs_to_usecs(data
->saved_latency
),
1491 #if defined(CONFIG_PREEMPT_NONE)
1493 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1495 #elif defined(CONFIG_PREEMPT)
1500 /* These are reserved for later use */
1503 seq_printf(m
, " #P:%d)\n", num_online_cpus());
1507 seq_puts(m
, "# -----------------\n");
1508 seq_printf(m
, "# | task: %.16s-%d "
1509 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1510 data
->comm
, data
->pid
, data
->uid
, data
->nice
,
1511 data
->policy
, data
->rt_priority
);
1512 seq_puts(m
, "# -----------------\n");
1514 if (data
->critical_start
) {
1515 seq_puts(m
, "# => started at: ");
1516 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
1517 trace_print_seq(m
, &iter
->seq
);
1518 seq_puts(m
, "\n# => ended at: ");
1519 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
1520 trace_print_seq(m
, &iter
->seq
);
1527 static void test_cpu_buff_start(struct trace_iterator
*iter
)
1529 struct trace_seq
*s
= &iter
->seq
;
1531 if (!(trace_flags
& TRACE_ITER_ANNOTATE
))
1534 if (!(iter
->iter_flags
& TRACE_FILE_ANNOTATE
))
1537 if (cpumask_test_cpu(iter
->cpu
, iter
->started
))
1540 cpumask_set_cpu(iter
->cpu
, iter
->started
);
1541 trace_seq_printf(s
, "##### CPU %u buffer started ####\n", iter
->cpu
);
1544 static enum print_line_t
print_trace_fmt(struct trace_iterator
*iter
)
1546 struct trace_seq
*s
= &iter
->seq
;
1547 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1548 struct trace_entry
*entry
;
1549 struct trace_event
*event
;
1553 test_cpu_buff_start(iter
);
1555 event
= ftrace_find_event(entry
->type
);
1557 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1558 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
1559 if (!trace_print_lat_context(iter
))
1562 if (!trace_print_context(iter
))
1568 return event
->trace(iter
, sym_flags
);
1570 if (!trace_seq_printf(s
, "Unknown type %d\n", entry
->type
))
1573 return TRACE_TYPE_HANDLED
;
1575 return TRACE_TYPE_PARTIAL_LINE
;
1578 static enum print_line_t
print_raw_fmt(struct trace_iterator
*iter
)
1580 struct trace_seq
*s
= &iter
->seq
;
1581 struct trace_entry
*entry
;
1582 struct trace_event
*event
;
1586 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1587 if (!trace_seq_printf(s
, "%d %d %llu ",
1588 entry
->pid
, iter
->cpu
, iter
->ts
))
1592 event
= ftrace_find_event(entry
->type
);
1594 return event
->raw(iter
, 0);
1596 if (!trace_seq_printf(s
, "%d ?\n", entry
->type
))
1599 return TRACE_TYPE_HANDLED
;
1601 return TRACE_TYPE_PARTIAL_LINE
;
1604 static enum print_line_t
print_hex_fmt(struct trace_iterator
*iter
)
1606 struct trace_seq
*s
= &iter
->seq
;
1607 unsigned char newline
= '\n';
1608 struct trace_entry
*entry
;
1609 struct trace_event
*event
;
1613 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1614 SEQ_PUT_HEX_FIELD_RET(s
, entry
->pid
);
1615 SEQ_PUT_HEX_FIELD_RET(s
, iter
->cpu
);
1616 SEQ_PUT_HEX_FIELD_RET(s
, iter
->ts
);
1619 event
= ftrace_find_event(entry
->type
);
1621 enum print_line_t ret
= event
->hex(iter
, 0);
1622 if (ret
!= TRACE_TYPE_HANDLED
)
1626 SEQ_PUT_FIELD_RET(s
, newline
);
1628 return TRACE_TYPE_HANDLED
;
1631 static enum print_line_t
print_printk_msg_only(struct trace_iterator
*iter
)
1633 struct trace_seq
*s
= &iter
->seq
;
1634 struct trace_entry
*entry
= iter
->ent
;
1635 struct print_entry
*field
;
1638 trace_assign_type(field
, entry
);
1640 ret
= trace_seq_bprintf(s
, field
->fmt
, field
->buf
);
1642 return TRACE_TYPE_PARTIAL_LINE
;
1644 return TRACE_TYPE_HANDLED
;
1647 static enum print_line_t
print_bin_fmt(struct trace_iterator
*iter
)
1649 struct trace_seq
*s
= &iter
->seq
;
1650 struct trace_entry
*entry
;
1651 struct trace_event
*event
;
1655 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1656 SEQ_PUT_FIELD_RET(s
, entry
->pid
);
1657 SEQ_PUT_FIELD_RET(s
, iter
->cpu
);
1658 SEQ_PUT_FIELD_RET(s
, iter
->ts
);
1661 event
= ftrace_find_event(entry
->type
);
1662 return event
? event
->binary(iter
, 0) : TRACE_TYPE_HANDLED
;
1665 static int trace_empty(struct trace_iterator
*iter
)
1669 /* If we are looking at one CPU buffer, only check that one */
1670 if (iter
->cpu_file
!= TRACE_PIPE_ALL_CPU
) {
1671 cpu
= iter
->cpu_file
;
1672 if (iter
->buffer_iter
[cpu
]) {
1673 if (!ring_buffer_iter_empty(iter
->buffer_iter
[cpu
]))
1676 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
1682 for_each_tracing_cpu(cpu
) {
1683 if (iter
->buffer_iter
[cpu
]) {
1684 if (!ring_buffer_iter_empty(iter
->buffer_iter
[cpu
]))
1687 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
1695 static enum print_line_t
print_trace_line(struct trace_iterator
*iter
)
1697 enum print_line_t ret
;
1699 if (iter
->trace
&& iter
->trace
->print_line
) {
1700 ret
= iter
->trace
->print_line(iter
);
1701 if (ret
!= TRACE_TYPE_UNHANDLED
)
1705 if (iter
->ent
->type
== TRACE_PRINT
&&
1706 trace_flags
& TRACE_ITER_PRINTK
&&
1707 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
1708 return print_printk_msg_only(iter
);
1710 if (trace_flags
& TRACE_ITER_BIN
)
1711 return print_bin_fmt(iter
);
1713 if (trace_flags
& TRACE_ITER_HEX
)
1714 return print_hex_fmt(iter
);
1716 if (trace_flags
& TRACE_ITER_RAW
)
1717 return print_raw_fmt(iter
);
1719 return print_trace_fmt(iter
);
1722 static int s_show(struct seq_file
*m
, void *v
)
1724 struct trace_iterator
*iter
= v
;
1726 if (iter
->ent
== NULL
) {
1728 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
1731 if (iter
->trace
&& iter
->trace
->print_header
)
1732 iter
->trace
->print_header(m
);
1733 else if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
1734 /* print nothing if the buffers are empty */
1735 if (trace_empty(iter
))
1737 print_trace_header(m
, iter
);
1738 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1739 print_lat_help_header(m
);
1741 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1742 print_func_help_header(m
);
1745 print_trace_line(iter
);
1746 trace_print_seq(m
, &iter
->seq
);
1752 static struct seq_operations tracer_seq_ops
= {
1759 static struct trace_iterator
*
1760 __tracing_open(struct inode
*inode
, struct file
*file
)
1762 long cpu_file
= (long) inode
->i_private
;
1763 void *fail_ret
= ERR_PTR(-ENOMEM
);
1764 struct trace_iterator
*iter
;
1768 if (tracing_disabled
)
1769 return ERR_PTR(-ENODEV
);
1771 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
1773 return ERR_PTR(-ENOMEM
);
1776 * We make a copy of the current tracer to avoid concurrent
1777 * changes on it while we are reading.
1779 mutex_lock(&trace_types_lock
);
1780 iter
->trace
= kzalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
1785 *iter
->trace
= *current_trace
;
1787 if (current_trace
&& current_trace
->print_max
)
1790 iter
->tr
= &global_trace
;
1792 mutex_init(&iter
->mutex
);
1793 iter
->cpu_file
= cpu_file
;
1795 /* Notify the tracer early; before we stop tracing. */
1796 if (iter
->trace
&& iter
->trace
->open
)
1797 iter
->trace
->open(iter
);
1799 /* Annotate start of buffers if we had overruns */
1800 if (ring_buffer_overruns(iter
->tr
->buffer
))
1801 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
1803 if (iter
->cpu_file
== TRACE_PIPE_ALL_CPU
) {
1804 for_each_tracing_cpu(cpu
) {
1806 iter
->buffer_iter
[cpu
] =
1807 ring_buffer_read_start(iter
->tr
->buffer
, cpu
);
1810 cpu
= iter
->cpu_file
;
1811 iter
->buffer_iter
[cpu
] =
1812 ring_buffer_read_start(iter
->tr
->buffer
, cpu
);
1815 /* TODO stop tracer */
1816 ret
= seq_open(file
, &tracer_seq_ops
);
1818 fail_ret
= ERR_PTR(ret
);
1822 m
= file
->private_data
;
1825 /* stop the trace while dumping */
1828 mutex_unlock(&trace_types_lock
);
1833 for_each_tracing_cpu(cpu
) {
1834 if (iter
->buffer_iter
[cpu
])
1835 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
1838 mutex_unlock(&trace_types_lock
);
1845 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
1847 if (tracing_disabled
)
1850 filp
->private_data
= inode
->i_private
;
1854 static int tracing_release(struct inode
*inode
, struct file
*file
)
1856 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
1857 struct trace_iterator
*iter
= m
->private;
1860 mutex_lock(&trace_types_lock
);
1861 for_each_tracing_cpu(cpu
) {
1862 if (iter
->buffer_iter
[cpu
])
1863 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
1866 if (iter
->trace
&& iter
->trace
->close
)
1867 iter
->trace
->close(iter
);
1869 /* reenable tracing if it was previously enabled */
1871 mutex_unlock(&trace_types_lock
);
1873 seq_release(inode
, file
);
1874 mutex_destroy(&iter
->mutex
);
1880 static int tracing_open(struct inode
*inode
, struct file
*file
)
1882 struct trace_iterator
*iter
;
1885 iter
= __tracing_open(inode
, file
);
1887 ret
= PTR_ERR(iter
);
1888 else if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
1889 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
1895 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1897 struct tracer
*t
= m
->private;
1909 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
1911 struct tracer
*t
= m
->private;
1914 mutex_lock(&trace_types_lock
);
1915 for (; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
1921 static void t_stop(struct seq_file
*m
, void *p
)
1923 mutex_unlock(&trace_types_lock
);
1926 static int t_show(struct seq_file
*m
, void *v
)
1928 struct tracer
*t
= v
;
1933 seq_printf(m
, "%s", t
->name
);
1942 static struct seq_operations show_traces_seq_ops
= {
1949 static int show_traces_open(struct inode
*inode
, struct file
*file
)
1953 if (tracing_disabled
)
1956 ret
= seq_open(file
, &show_traces_seq_ops
);
1958 struct seq_file
*m
= file
->private_data
;
1959 m
->private = trace_types
;
1965 static const struct file_operations tracing_fops
= {
1966 .open
= tracing_open
,
1968 .llseek
= seq_lseek
,
1969 .release
= tracing_release
,
1972 static const struct file_operations show_traces_fops
= {
1973 .open
= show_traces_open
,
1975 .release
= seq_release
,
1979 * Only trace on a CPU if the bitmask is set:
1981 static cpumask_var_t tracing_cpumask
;
1984 * The tracer itself will not take this lock, but still we want
1985 * to provide a consistent cpumask to user-space:
1987 static DEFINE_MUTEX(tracing_cpumask_update_lock
);
1990 * Temporary storage for the character representation of the
1991 * CPU bitmask (and one more byte for the newline):
1993 static char mask_str
[NR_CPUS
+ 1];
1996 tracing_cpumask_read(struct file
*filp
, char __user
*ubuf
,
1997 size_t count
, loff_t
*ppos
)
2001 mutex_lock(&tracing_cpumask_update_lock
);
2003 len
= cpumask_scnprintf(mask_str
, count
, tracing_cpumask
);
2004 if (count
- len
< 2) {
2008 len
+= sprintf(mask_str
+ len
, "\n");
2009 count
= simple_read_from_buffer(ubuf
, count
, ppos
, mask_str
, NR_CPUS
+1);
2012 mutex_unlock(&tracing_cpumask_update_lock
);
2018 tracing_cpumask_write(struct file
*filp
, const char __user
*ubuf
,
2019 size_t count
, loff_t
*ppos
)
2022 cpumask_var_t tracing_cpumask_new
;
2024 if (!alloc_cpumask_var(&tracing_cpumask_new
, GFP_KERNEL
))
2027 mutex_lock(&tracing_cpumask_update_lock
);
2028 err
= cpumask_parse_user(ubuf
, count
, tracing_cpumask_new
);
2032 local_irq_disable();
2033 __raw_spin_lock(&ftrace_max_lock
);
2034 for_each_tracing_cpu(cpu
) {
2036 * Increase/decrease the disabled counter if we are
2037 * about to flip a bit in the cpumask:
2039 if (cpumask_test_cpu(cpu
, tracing_cpumask
) &&
2040 !cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
2041 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
2043 if (!cpumask_test_cpu(cpu
, tracing_cpumask
) &&
2044 cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
2045 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
2048 __raw_spin_unlock(&ftrace_max_lock
);
2051 cpumask_copy(tracing_cpumask
, tracing_cpumask_new
);
2053 mutex_unlock(&tracing_cpumask_update_lock
);
2054 free_cpumask_var(tracing_cpumask_new
);
2059 mutex_unlock(&tracing_cpumask_update_lock
);
2060 free_cpumask_var(tracing_cpumask
);
2065 static const struct file_operations tracing_cpumask_fops
= {
2066 .open
= tracing_open_generic
,
2067 .read
= tracing_cpumask_read
,
2068 .write
= tracing_cpumask_write
,
2072 tracing_trace_options_read(struct file
*filp
, char __user
*ubuf
,
2073 size_t cnt
, loff_t
*ppos
)
2075 struct tracer_opt
*trace_opts
;
2083 /* calculate max size */
2084 for (i
= 0; trace_options
[i
]; i
++) {
2085 len
+= strlen(trace_options
[i
]);
2086 len
+= 3; /* "no" and newline */
2089 mutex_lock(&trace_types_lock
);
2090 tracer_flags
= current_trace
->flags
->val
;
2091 trace_opts
= current_trace
->flags
->opts
;
2094 * Increase the size with names of options specific
2095 * of the current tracer.
2097 for (i
= 0; trace_opts
[i
].name
; i
++) {
2098 len
+= strlen(trace_opts
[i
].name
);
2099 len
+= 3; /* "no" and newline */
2102 /* +2 for \n and \0 */
2103 buf
= kmalloc(len
+ 2, GFP_KERNEL
);
2105 mutex_unlock(&trace_types_lock
);
2109 for (i
= 0; trace_options
[i
]; i
++) {
2110 if (trace_flags
& (1 << i
))
2111 r
+= sprintf(buf
+ r
, "%s\n", trace_options
[i
]);
2113 r
+= sprintf(buf
+ r
, "no%s\n", trace_options
[i
]);
2116 for (i
= 0; trace_opts
[i
].name
; i
++) {
2117 if (tracer_flags
& trace_opts
[i
].bit
)
2118 r
+= sprintf(buf
+ r
, "%s\n",
2119 trace_opts
[i
].name
);
2121 r
+= sprintf(buf
+ r
, "no%s\n",
2122 trace_opts
[i
].name
);
2124 mutex_unlock(&trace_types_lock
);
2126 WARN_ON(r
>= len
+ 2);
2128 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2134 /* Try to assign a tracer specific option */
2135 static int set_tracer_option(struct tracer
*trace
, char *cmp
, int neg
)
2137 struct tracer_flags
*trace_flags
= trace
->flags
;
2138 struct tracer_opt
*opts
= NULL
;
2142 for (i
= 0; trace_flags
->opts
[i
].name
; i
++) {
2143 opts
= &trace_flags
->opts
[i
];
2144 len
= strlen(opts
->name
);
2146 if (strncmp(cmp
, opts
->name
, len
) == 0) {
2147 ret
= trace
->set_flag(trace_flags
->val
,
2153 if (!trace_flags
->opts
[i
].name
)
2156 /* Refused to handle */
2161 trace_flags
->val
&= ~opts
->bit
;
2163 trace_flags
->val
|= opts
->bit
;
2169 tracing_trace_options_write(struct file
*filp
, const char __user
*ubuf
,
2170 size_t cnt
, loff_t
*ppos
)
2178 if (cnt
>= sizeof(buf
))
2181 if (copy_from_user(&buf
, ubuf
, cnt
))
2186 if (strncmp(buf
, "no", 2) == 0) {
2191 for (i
= 0; trace_options
[i
]; i
++) {
2192 int len
= strlen(trace_options
[i
]);
2194 if (strncmp(cmp
, trace_options
[i
], len
) == 0) {
2196 trace_flags
&= ~(1 << i
);
2198 trace_flags
|= (1 << i
);
2203 /* If no option could be set, test the specific tracer options */
2204 if (!trace_options
[i
]) {
2205 mutex_lock(&trace_types_lock
);
2206 ret
= set_tracer_option(current_trace
, cmp
, neg
);
2207 mutex_unlock(&trace_types_lock
);
2217 static const struct file_operations tracing_iter_fops
= {
2218 .open
= tracing_open_generic
,
2219 .read
= tracing_trace_options_read
,
2220 .write
= tracing_trace_options_write
,
2223 static const char readme_msg
[] =
2224 "tracing mini-HOWTO:\n\n"
2226 "# mount -t debugfs nodev /debug\n\n"
2227 "# cat /debug/tracing/available_tracers\n"
2228 "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
2229 "# cat /debug/tracing/current_tracer\n"
2231 "# echo sched_switch > /debug/tracing/current_tracer\n"
2232 "# cat /debug/tracing/current_tracer\n"
2234 "# cat /debug/tracing/trace_options\n"
2235 "noprint-parent nosym-offset nosym-addr noverbose\n"
2236 "# echo print-parent > /debug/tracing/trace_options\n"
2237 "# echo 1 > /debug/tracing/tracing_enabled\n"
2238 "# cat /debug/tracing/trace > /tmp/trace.txt\n"
2239 "echo 0 > /debug/tracing/tracing_enabled\n"
2243 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
2244 size_t cnt
, loff_t
*ppos
)
2246 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
2247 readme_msg
, strlen(readme_msg
));
2250 static const struct file_operations tracing_readme_fops
= {
2251 .open
= tracing_open_generic
,
2252 .read
= tracing_readme_read
,
2256 tracing_ctrl_read(struct file
*filp
, char __user
*ubuf
,
2257 size_t cnt
, loff_t
*ppos
)
2262 r
= sprintf(buf
, "%u\n", tracer_enabled
);
2263 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2267 tracing_ctrl_write(struct file
*filp
, const char __user
*ubuf
,
2268 size_t cnt
, loff_t
*ppos
)
2270 struct trace_array
*tr
= filp
->private_data
;
2275 if (cnt
>= sizeof(buf
))
2278 if (copy_from_user(&buf
, ubuf
, cnt
))
2283 ret
= strict_strtoul(buf
, 10, &val
);
2289 mutex_lock(&trace_types_lock
);
2290 if (tracer_enabled
^ val
) {
2293 if (current_trace
->start
)
2294 current_trace
->start(tr
);
2299 if (current_trace
->stop
)
2300 current_trace
->stop(tr
);
2303 mutex_unlock(&trace_types_lock
);
2311 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
2312 size_t cnt
, loff_t
*ppos
)
2314 char buf
[max_tracer_type_len
+2];
2317 mutex_lock(&trace_types_lock
);
2319 r
= sprintf(buf
, "%s\n", current_trace
->name
);
2321 r
= sprintf(buf
, "\n");
2322 mutex_unlock(&trace_types_lock
);
2324 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2327 int tracer_init(struct tracer
*t
, struct trace_array
*tr
)
2329 tracing_reset_online_cpus(tr
);
2333 static int tracing_resize_ring_buffer(unsigned long size
)
2338 * If kernel or user changes the size of the ring buffer
2339 * we use the size that was given, and we can forget about
2340 * expanding it later.
2342 ring_buffer_expanded
= 1;
2344 ret
= ring_buffer_resize(global_trace
.buffer
, size
);
2348 ret
= ring_buffer_resize(max_tr
.buffer
, size
);
2352 r
= ring_buffer_resize(global_trace
.buffer
,
2353 global_trace
.entries
);
2356 * AARGH! We are left with different
2357 * size max buffer!!!!
2358 * The max buffer is our "snapshot" buffer.
2359 * When a tracer needs a snapshot (one of the
2360 * latency tracers), it swaps the max buffer
2361 * with the saved snap shot. We succeeded to
2362 * update the size of the main buffer, but failed to
2363 * update the size of the max buffer. But when we tried
2364 * to reset the main buffer to the original size, we
2365 * failed there too. This is very unlikely to
2366 * happen, but if it does, warn and kill all
2370 tracing_disabled
= 1;
2375 global_trace
.entries
= size
;
2381 * tracing_update_buffers - used by tracing facility to expand ring buffers
2383 * To save on memory when the tracing is never used on a system with it
2384 * configured in. The ring buffers are set to a minimum size. But once
2385 * a user starts to use the tracing facility, then they need to grow
2386 * to their default size.
2388 * This function is to be called when a tracer is about to be used.
2390 int tracing_update_buffers(void)
2394 mutex_lock(&trace_types_lock
);
2395 if (!ring_buffer_expanded
)
2396 ret
= tracing_resize_ring_buffer(trace_buf_size
);
2397 mutex_unlock(&trace_types_lock
);
2402 struct trace_option_dentry
;
2404 static struct trace_option_dentry
*
2405 create_trace_option_files(struct tracer
*tracer
);
2408 destroy_trace_option_files(struct trace_option_dentry
*topts
);
2410 static int tracing_set_tracer(const char *buf
)
2412 static struct trace_option_dentry
*topts
;
2413 struct trace_array
*tr
= &global_trace
;
2417 mutex_lock(&trace_types_lock
);
2419 if (!ring_buffer_expanded
) {
2420 ret
= tracing_resize_ring_buffer(trace_buf_size
);
2426 for (t
= trace_types
; t
; t
= t
->next
) {
2427 if (strcmp(t
->name
, buf
) == 0)
2434 if (t
== current_trace
)
2437 trace_branch_disable();
2438 if (current_trace
&& current_trace
->reset
)
2439 current_trace
->reset(tr
);
2441 destroy_trace_option_files(topts
);
2445 topts
= create_trace_option_files(current_trace
);
2448 ret
= tracer_init(t
, tr
);
2453 trace_branch_enable(tr
);
2455 mutex_unlock(&trace_types_lock
);
2461 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
2462 size_t cnt
, loff_t
*ppos
)
2464 char buf
[max_tracer_type_len
+1];
2471 if (cnt
> max_tracer_type_len
)
2472 cnt
= max_tracer_type_len
;
2474 if (copy_from_user(&buf
, ubuf
, cnt
))
2479 /* strip ending whitespace. */
2480 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
2483 err
= tracing_set_tracer(buf
);
2493 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
2494 size_t cnt
, loff_t
*ppos
)
2496 unsigned long *ptr
= filp
->private_data
;
2500 r
= snprintf(buf
, sizeof(buf
), "%ld\n",
2501 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
2502 if (r
> sizeof(buf
))
2504 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2508 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
2509 size_t cnt
, loff_t
*ppos
)
2511 unsigned long *ptr
= filp
->private_data
;
2516 if (cnt
>= sizeof(buf
))
2519 if (copy_from_user(&buf
, ubuf
, cnt
))
2524 ret
= strict_strtoul(buf
, 10, &val
);
2533 static int tracing_open_pipe(struct inode
*inode
, struct file
*filp
)
2535 long cpu_file
= (long) inode
->i_private
;
2536 struct trace_iterator
*iter
;
2539 if (tracing_disabled
)
2542 mutex_lock(&trace_types_lock
);
2544 /* We only allow one reader per cpu */
2545 if (cpu_file
== TRACE_PIPE_ALL_CPU
) {
2546 if (!cpumask_empty(tracing_reader_cpumask
)) {
2550 cpumask_setall(tracing_reader_cpumask
);
2552 if (!cpumask_test_cpu(cpu_file
, tracing_reader_cpumask
))
2553 cpumask_set_cpu(cpu_file
, tracing_reader_cpumask
);
2560 /* create a buffer to store the information to pass to userspace */
2561 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2568 * We make a copy of the current tracer to avoid concurrent
2569 * changes on it while we are reading.
2571 iter
->trace
= kmalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
2577 *iter
->trace
= *current_trace
;
2579 if (!alloc_cpumask_var(&iter
->started
, GFP_KERNEL
)) {
2584 /* trace pipe does not show start of buffer */
2585 cpumask_setall(iter
->started
);
2587 iter
->cpu_file
= cpu_file
;
2588 iter
->tr
= &global_trace
;
2589 mutex_init(&iter
->mutex
);
2590 filp
->private_data
= iter
;
2592 if (iter
->trace
->pipe_open
)
2593 iter
->trace
->pipe_open(iter
);
2596 mutex_unlock(&trace_types_lock
);
2602 mutex_unlock(&trace_types_lock
);
2606 static int tracing_release_pipe(struct inode
*inode
, struct file
*file
)
2608 struct trace_iterator
*iter
= file
->private_data
;
2610 mutex_lock(&trace_types_lock
);
2612 if (iter
->cpu_file
== TRACE_PIPE_ALL_CPU
)
2613 cpumask_clear(tracing_reader_cpumask
);
2615 cpumask_clear_cpu(iter
->cpu_file
, tracing_reader_cpumask
);
2617 mutex_unlock(&trace_types_lock
);
2619 free_cpumask_var(iter
->started
);
2620 mutex_destroy(&iter
->mutex
);
2628 tracing_poll_pipe(struct file
*filp
, poll_table
*poll_table
)
2630 struct trace_iterator
*iter
= filp
->private_data
;
2632 if (trace_flags
& TRACE_ITER_BLOCK
) {
2634 * Always select as readable when in blocking mode
2636 return POLLIN
| POLLRDNORM
;
2638 if (!trace_empty(iter
))
2639 return POLLIN
| POLLRDNORM
;
2640 poll_wait(filp
, &trace_wait
, poll_table
);
2641 if (!trace_empty(iter
))
2642 return POLLIN
| POLLRDNORM
;
2649 void default_wait_pipe(struct trace_iterator
*iter
)
2653 prepare_to_wait(&trace_wait
, &wait
, TASK_INTERRUPTIBLE
);
2655 if (trace_empty(iter
))
2658 finish_wait(&trace_wait
, &wait
);
2662 * This is a make-shift waitqueue.
2663 * A tracer might use this callback on some rare cases:
2665 * 1) the current tracer might hold the runqueue lock when it wakes up
2666 * a reader, hence a deadlock (sched, function, and function graph tracers)
2667 * 2) the function tracers, trace all functions, we don't want
2668 * the overhead of calling wake_up and friends
2669 * (and tracing them too)
2671 * Anyway, this is really very primitive wakeup.
2673 void poll_wait_pipe(struct trace_iterator
*iter
)
2675 set_current_state(TASK_INTERRUPTIBLE
);
2676 /* sleep for 100 msecs, and try again. */
2677 schedule_timeout(HZ
/ 10);
2680 /* Must be called with trace_types_lock mutex held. */
2681 static int tracing_wait_pipe(struct file
*filp
)
2683 struct trace_iterator
*iter
= filp
->private_data
;
2685 while (trace_empty(iter
)) {
2687 if ((filp
->f_flags
& O_NONBLOCK
)) {
2691 mutex_unlock(&iter
->mutex
);
2693 iter
->trace
->wait_pipe(iter
);
2695 mutex_lock(&iter
->mutex
);
2697 if (signal_pending(current
))
2701 * We block until we read something and tracing is disabled.
2702 * We still block if tracing is disabled, but we have never
2703 * read anything. This allows a user to cat this file, and
2704 * then enable tracing. But after we have read something,
2705 * we give an EOF when tracing is again disabled.
2707 * iter->pos will be 0 if we haven't read anything.
2709 if (!tracer_enabled
&& iter
->pos
)
2720 tracing_read_pipe(struct file
*filp
, char __user
*ubuf
,
2721 size_t cnt
, loff_t
*ppos
)
2723 struct trace_iterator
*iter
= filp
->private_data
;
2724 static struct tracer
*old_tracer
;
2727 /* return any leftover data */
2728 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
2732 trace_seq_init(&iter
->seq
);
2734 /* copy the tracer to avoid using a global lock all around */
2735 mutex_lock(&trace_types_lock
);
2736 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
2737 old_tracer
= current_trace
;
2738 *iter
->trace
= *current_trace
;
2740 mutex_unlock(&trace_types_lock
);
2743 * Avoid more than one consumer on a single file descriptor
2744 * This is just a matter of traces coherency, the ring buffer itself
2747 mutex_lock(&iter
->mutex
);
2748 if (iter
->trace
->read
) {
2749 sret
= iter
->trace
->read(iter
, filp
, ubuf
, cnt
, ppos
);
2755 sret
= tracing_wait_pipe(filp
);
2759 /* stop when tracing is finished */
2760 if (trace_empty(iter
)) {
2765 if (cnt
>= PAGE_SIZE
)
2766 cnt
= PAGE_SIZE
- 1;
2768 /* reset all but tr, trace, and overruns */
2769 memset(&iter
->seq
, 0,
2770 sizeof(struct trace_iterator
) -
2771 offsetof(struct trace_iterator
, seq
));
2774 while (find_next_entry_inc(iter
) != NULL
) {
2775 enum print_line_t ret
;
2776 int len
= iter
->seq
.len
;
2778 ret
= print_trace_line(iter
);
2779 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
2780 /* don't print partial lines */
2781 iter
->seq
.len
= len
;
2784 if (ret
!= TRACE_TYPE_NO_CONSUME
)
2785 trace_consume(iter
);
2787 if (iter
->seq
.len
>= cnt
)
2791 /* Now copy what we have to the user */
2792 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
2793 if (iter
->seq
.readpos
>= iter
->seq
.len
)
2794 trace_seq_init(&iter
->seq
);
2797 * If there was nothing to send to user, inspite of consuming trace
2798 * entries, go back to wait for more entries.
2804 mutex_unlock(&iter
->mutex
);
2809 static void tracing_pipe_buf_release(struct pipe_inode_info
*pipe
,
2810 struct pipe_buffer
*buf
)
2812 __free_page(buf
->page
);
2815 static void tracing_spd_release_pipe(struct splice_pipe_desc
*spd
,
2818 __free_page(spd
->pages
[idx
]);
2821 static struct pipe_buf_operations tracing_pipe_buf_ops
= {
2823 .map
= generic_pipe_buf_map
,
2824 .unmap
= generic_pipe_buf_unmap
,
2825 .confirm
= generic_pipe_buf_confirm
,
2826 .release
= tracing_pipe_buf_release
,
2827 .steal
= generic_pipe_buf_steal
,
2828 .get
= generic_pipe_buf_get
,
2832 tracing_fill_pipe_page(size_t rem
, struct trace_iterator
*iter
)
2837 /* Seq buffer is page-sized, exactly what we need. */
2839 count
= iter
->seq
.len
;
2840 ret
= print_trace_line(iter
);
2841 count
= iter
->seq
.len
- count
;
2844 iter
->seq
.len
-= count
;
2847 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
2848 iter
->seq
.len
-= count
;
2852 trace_consume(iter
);
2854 if (!find_next_entry_inc(iter
)) {
2864 static ssize_t
tracing_splice_read_pipe(struct file
*filp
,
2866 struct pipe_inode_info
*pipe
,
2870 struct page
*pages
[PIPE_BUFFERS
];
2871 struct partial_page partial
[PIPE_BUFFERS
];
2872 struct trace_iterator
*iter
= filp
->private_data
;
2873 struct splice_pipe_desc spd
= {
2876 .nr_pages
= 0, /* This gets updated below. */
2878 .ops
= &tracing_pipe_buf_ops
,
2879 .spd_release
= tracing_spd_release_pipe
,
2881 static struct tracer
*old_tracer
;
2886 /* copy the tracer to avoid using a global lock all around */
2887 mutex_lock(&trace_types_lock
);
2888 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
2889 old_tracer
= current_trace
;
2890 *iter
->trace
= *current_trace
;
2892 mutex_unlock(&trace_types_lock
);
2894 mutex_lock(&iter
->mutex
);
2896 if (iter
->trace
->splice_read
) {
2897 ret
= iter
->trace
->splice_read(iter
, filp
,
2898 ppos
, pipe
, len
, flags
);
2903 ret
= tracing_wait_pipe(filp
);
2907 if (!iter
->ent
&& !find_next_entry_inc(iter
)) {
2912 /* Fill as many pages as possible. */
2913 for (i
= 0, rem
= len
; i
< PIPE_BUFFERS
&& rem
; i
++) {
2914 pages
[i
] = alloc_page(GFP_KERNEL
);
2918 rem
= tracing_fill_pipe_page(rem
, iter
);
2920 /* Copy the data into the page, so we can start over. */
2921 ret
= trace_seq_to_buffer(&iter
->seq
,
2922 page_address(pages
[i
]),
2925 __free_page(pages
[i
]);
2928 partial
[i
].offset
= 0;
2929 partial
[i
].len
= iter
->seq
.len
;
2931 trace_seq_init(&iter
->seq
);
2934 mutex_unlock(&iter
->mutex
);
2938 return splice_to_pipe(pipe
, &spd
);
2941 mutex_unlock(&iter
->mutex
);
2947 tracing_entries_read(struct file
*filp
, char __user
*ubuf
,
2948 size_t cnt
, loff_t
*ppos
)
2950 struct trace_array
*tr
= filp
->private_data
;
2954 mutex_lock(&trace_types_lock
);
2955 if (!ring_buffer_expanded
)
2956 r
= sprintf(buf
, "%lu (expanded: %lu)\n",
2958 trace_buf_size
>> 10);
2960 r
= sprintf(buf
, "%lu\n", tr
->entries
>> 10);
2961 mutex_unlock(&trace_types_lock
);
2963 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2967 tracing_entries_write(struct file
*filp
, const char __user
*ubuf
,
2968 size_t cnt
, loff_t
*ppos
)
2974 if (cnt
>= sizeof(buf
))
2977 if (copy_from_user(&buf
, ubuf
, cnt
))
2982 ret
= strict_strtoul(buf
, 10, &val
);
2986 /* must have at least 1 entry */
2990 mutex_lock(&trace_types_lock
);
2994 /* disable all cpu buffers */
2995 for_each_tracing_cpu(cpu
) {
2996 if (global_trace
.data
[cpu
])
2997 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
2998 if (max_tr
.data
[cpu
])
2999 atomic_inc(&max_tr
.data
[cpu
]->disabled
);
3002 /* value is in KB */
3005 if (val
!= global_trace
.entries
) {
3006 ret
= tracing_resize_ring_buffer(val
);
3015 /* If check pages failed, return ENOMEM */
3016 if (tracing_disabled
)
3019 for_each_tracing_cpu(cpu
) {
3020 if (global_trace
.data
[cpu
])
3021 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
3022 if (max_tr
.data
[cpu
])
3023 atomic_dec(&max_tr
.data
[cpu
]->disabled
);
3027 max_tr
.entries
= global_trace
.entries
;
3028 mutex_unlock(&trace_types_lock
);
3033 static int mark_printk(const char *fmt
, ...)
3037 va_start(args
, fmt
);
3038 ret
= trace_vprintk(0, -1, fmt
, args
);
3044 tracing_mark_write(struct file
*filp
, const char __user
*ubuf
,
3045 size_t cnt
, loff_t
*fpos
)
3050 if (tracing_disabled
)
3053 if (cnt
> TRACE_BUF_SIZE
)
3054 cnt
= TRACE_BUF_SIZE
;
3056 buf
= kmalloc(cnt
+ 1, GFP_KERNEL
);
3060 if (copy_from_user(buf
, ubuf
, cnt
)) {
3065 /* Cut from the first nil or newline. */
3067 end
= strchr(buf
, '\n');
3071 cnt
= mark_printk("%s\n", buf
);
3078 static const struct file_operations tracing_max_lat_fops
= {
3079 .open
= tracing_open_generic
,
3080 .read
= tracing_max_lat_read
,
3081 .write
= tracing_max_lat_write
,
3084 static const struct file_operations tracing_ctrl_fops
= {
3085 .open
= tracing_open_generic
,
3086 .read
= tracing_ctrl_read
,
3087 .write
= tracing_ctrl_write
,
3090 static const struct file_operations set_tracer_fops
= {
3091 .open
= tracing_open_generic
,
3092 .read
= tracing_set_trace_read
,
3093 .write
= tracing_set_trace_write
,
3096 static const struct file_operations tracing_pipe_fops
= {
3097 .open
= tracing_open_pipe
,
3098 .poll
= tracing_poll_pipe
,
3099 .read
= tracing_read_pipe
,
3100 .splice_read
= tracing_splice_read_pipe
,
3101 .release
= tracing_release_pipe
,
3104 static const struct file_operations tracing_entries_fops
= {
3105 .open
= tracing_open_generic
,
3106 .read
= tracing_entries_read
,
3107 .write
= tracing_entries_write
,
3110 static const struct file_operations tracing_mark_fops
= {
3111 .open
= tracing_open_generic
,
3112 .write
= tracing_mark_write
,
3115 struct ftrace_buffer_info
{
3116 struct trace_array
*tr
;
3122 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
)
3124 int cpu
= (int)(long)inode
->i_private
;
3125 struct ftrace_buffer_info
*info
;
3127 if (tracing_disabled
)
3130 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
3134 info
->tr
= &global_trace
;
3136 info
->spare
= ring_buffer_alloc_read_page(info
->tr
->buffer
);
3137 /* Force reading ring buffer for first read */
3138 info
->read
= (unsigned int)-1;
3142 filp
->private_data
= info
;
3152 tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
3153 size_t count
, loff_t
*ppos
)
3155 struct ftrace_buffer_info
*info
= filp
->private_data
;
3163 /* Do we have previous read data to read? */
3164 if (info
->read
< PAGE_SIZE
)
3169 ret
= ring_buffer_read_page(info
->tr
->buffer
,
3176 pos
= ring_buffer_page_len(info
->spare
);
3178 if (pos
< PAGE_SIZE
)
3179 memset(info
->spare
+ pos
, 0, PAGE_SIZE
- pos
);
3182 size
= PAGE_SIZE
- info
->read
;
3186 ret
= copy_to_user(ubuf
, info
->spare
+ info
->read
, size
);
3197 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
)
3199 struct ftrace_buffer_info
*info
= file
->private_data
;
3201 ring_buffer_free_read_page(info
->tr
->buffer
, info
->spare
);
3208 struct ring_buffer
*buffer
;
3213 static void buffer_pipe_buf_release(struct pipe_inode_info
*pipe
,
3214 struct pipe_buffer
*buf
)
3216 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
3221 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
3226 static int buffer_pipe_buf_steal(struct pipe_inode_info
*pipe
,
3227 struct pipe_buffer
*buf
)
3232 static void buffer_pipe_buf_get(struct pipe_inode_info
*pipe
,
3233 struct pipe_buffer
*buf
)
3235 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
3240 /* Pipe buffer operations for a buffer. */
3241 static struct pipe_buf_operations buffer_pipe_buf_ops
= {
3243 .map
= generic_pipe_buf_map
,
3244 .unmap
= generic_pipe_buf_unmap
,
3245 .confirm
= generic_pipe_buf_confirm
,
3246 .release
= buffer_pipe_buf_release
,
3247 .steal
= buffer_pipe_buf_steal
,
3248 .get
= buffer_pipe_buf_get
,
3252 * Callback from splice_to_pipe(), if we need to release some pages
3253 * at the end of the spd in case we error'ed out in filling the pipe.
3255 static void buffer_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
3257 struct buffer_ref
*ref
=
3258 (struct buffer_ref
*)spd
->partial
[i
].private;
3263 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
3265 spd
->partial
[i
].private = 0;
3269 tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
3270 struct pipe_inode_info
*pipe
, size_t len
,
3273 struct ftrace_buffer_info
*info
= file
->private_data
;
3274 struct partial_page partial
[PIPE_BUFFERS
];
3275 struct page
*pages
[PIPE_BUFFERS
];
3276 struct splice_pipe_desc spd
= {
3280 .ops
= &buffer_pipe_buf_ops
,
3281 .spd_release
= buffer_spd_release
,
3283 struct buffer_ref
*ref
;
3288 * We can't seek on a buffer input
3290 if (unlikely(*ppos
))
3294 for (i
= 0; i
< PIPE_BUFFERS
&& len
; i
++, len
-= size
) {
3298 ref
= kzalloc(sizeof(*ref
), GFP_KERNEL
);
3302 ref
->buffer
= info
->tr
->buffer
;
3303 ref
->page
= ring_buffer_alloc_read_page(ref
->buffer
);
3309 r
= ring_buffer_read_page(ref
->buffer
, &ref
->page
,
3312 ring_buffer_free_read_page(ref
->buffer
,
3319 * zero out any left over data, this is going to
3322 size
= ring_buffer_page_len(ref
->page
);
3323 if (size
< PAGE_SIZE
)
3324 memset(ref
->page
+ size
, 0, PAGE_SIZE
- size
);
3326 page
= virt_to_page(ref
->page
);
3328 spd
.pages
[i
] = page
;
3329 spd
.partial
[i
].len
= PAGE_SIZE
;
3330 spd
.partial
[i
].offset
= 0;
3331 spd
.partial
[i
].private = (unsigned long)ref
;
3337 /* did we read anything? */
3338 if (!spd
.nr_pages
) {
3339 if (flags
& SPLICE_F_NONBLOCK
)
3347 ret
= splice_to_pipe(pipe
, &spd
);
3352 static const struct file_operations tracing_buffers_fops
= {
3353 .open
= tracing_buffers_open
,
3354 .read
= tracing_buffers_read
,
3355 .release
= tracing_buffers_release
,
3356 .splice_read
= tracing_buffers_splice_read
,
3357 .llseek
= no_llseek
,
3360 #ifdef CONFIG_DYNAMIC_FTRACE
3362 int __weak
ftrace_arch_read_dyn_info(char *buf
, int size
)
3368 tracing_read_dyn_info(struct file
*filp
, char __user
*ubuf
,
3369 size_t cnt
, loff_t
*ppos
)
3371 static char ftrace_dyn_info_buffer
[1024];
3372 static DEFINE_MUTEX(dyn_info_mutex
);
3373 unsigned long *p
= filp
->private_data
;
3374 char *buf
= ftrace_dyn_info_buffer
;
3375 int size
= ARRAY_SIZE(ftrace_dyn_info_buffer
);
3378 mutex_lock(&dyn_info_mutex
);
3379 r
= sprintf(buf
, "%ld ", *p
);
3381 r
+= ftrace_arch_read_dyn_info(buf
+r
, (size
-1)-r
);
3384 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3386 mutex_unlock(&dyn_info_mutex
);
3391 static const struct file_operations tracing_dyn_info_fops
= {
3392 .open
= tracing_open_generic
,
3393 .read
= tracing_read_dyn_info
,
3397 static struct dentry
*d_tracer
;
3399 struct dentry
*tracing_init_dentry(void)
3406 d_tracer
= debugfs_create_dir("tracing", NULL
);
3408 if (!d_tracer
&& !once
) {
3410 pr_warning("Could not create debugfs directory 'tracing'\n");
3417 static struct dentry
*d_percpu
;
3419 struct dentry
*tracing_dentry_percpu(void)
3422 struct dentry
*d_tracer
;
3427 d_tracer
= tracing_init_dentry();
3432 d_percpu
= debugfs_create_dir("per_cpu", d_tracer
);
3434 if (!d_percpu
&& !once
) {
3436 pr_warning("Could not create debugfs directory 'per_cpu'\n");
3443 static void tracing_init_debugfs_percpu(long cpu
)
3445 struct dentry
*d_percpu
= tracing_dentry_percpu();
3446 struct dentry
*entry
, *d_cpu
;
3447 /* strlen(cpu) + MAX(log10(cpu)) + '\0' */
3450 if (cpu
> 999 || cpu
< 0)
3453 sprintf(cpu_dir
, "cpu%ld", cpu
);
3454 d_cpu
= debugfs_create_dir(cpu_dir
, d_percpu
);
3456 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir
);
3460 /* per cpu trace_pipe */
3461 entry
= debugfs_create_file("trace_pipe", 0444, d_cpu
,
3462 (void *) cpu
, &tracing_pipe_fops
);
3464 pr_warning("Could not create debugfs 'trace_pipe' entry\n");
3467 entry
= debugfs_create_file("trace", 0444, d_cpu
,
3468 (void *) cpu
, &tracing_fops
);
3470 pr_warning("Could not create debugfs 'trace' entry\n");
3473 #ifdef CONFIG_FTRACE_SELFTEST
3474 /* Let selftest have access to static functions in this file */
3475 #include "trace_selftest.c"
3478 struct trace_option_dentry
{
3479 struct tracer_opt
*opt
;
3480 struct tracer_flags
*flags
;
3481 struct dentry
*entry
;
3485 trace_options_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
3488 struct trace_option_dentry
*topt
= filp
->private_data
;
3491 if (topt
->flags
->val
& topt
->opt
->bit
)
3496 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
3500 trace_options_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
3503 struct trace_option_dentry
*topt
= filp
->private_data
;
3508 if (cnt
>= sizeof(buf
))
3511 if (copy_from_user(&buf
, ubuf
, cnt
))
3516 ret
= strict_strtoul(buf
, 10, &val
);
3523 /* do nothing if already cleared */
3524 if (!(topt
->flags
->val
& topt
->opt
->bit
))
3527 mutex_lock(&trace_types_lock
);
3528 if (current_trace
->set_flag
)
3529 ret
= current_trace
->set_flag(topt
->flags
->val
,
3531 mutex_unlock(&trace_types_lock
);
3534 topt
->flags
->val
&= ~topt
->opt
->bit
;
3537 /* do nothing if already set */
3538 if (topt
->flags
->val
& topt
->opt
->bit
)
3541 mutex_lock(&trace_types_lock
);
3542 if (current_trace
->set_flag
)
3543 ret
= current_trace
->set_flag(topt
->flags
->val
,
3545 mutex_unlock(&trace_types_lock
);
3548 topt
->flags
->val
|= topt
->opt
->bit
;
3561 static const struct file_operations trace_options_fops
= {
3562 .open
= tracing_open_generic
,
3563 .read
= trace_options_read
,
3564 .write
= trace_options_write
,
3568 trace_options_core_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
3571 long index
= (long)filp
->private_data
;
3574 if (trace_flags
& (1 << index
))
3579 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
3583 trace_options_core_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
3586 long index
= (long)filp
->private_data
;
3591 if (cnt
>= sizeof(buf
))
3594 if (copy_from_user(&buf
, ubuf
, cnt
))
3599 ret
= strict_strtoul(buf
, 10, &val
);
3605 trace_flags
&= ~(1 << index
);
3608 trace_flags
|= 1 << index
;
3620 static const struct file_operations trace_options_core_fops
= {
3621 .open
= tracing_open_generic
,
3622 .read
= trace_options_core_read
,
3623 .write
= trace_options_core_write
,
3626 static struct dentry
*trace_options_init_dentry(void)
3628 struct dentry
*d_tracer
;
3629 static struct dentry
*t_options
;
3634 d_tracer
= tracing_init_dentry();
3638 t_options
= debugfs_create_dir("options", d_tracer
);
3640 pr_warning("Could not create debugfs directory 'options'\n");
3648 create_trace_option_file(struct trace_option_dentry
*topt
,
3649 struct tracer_flags
*flags
,
3650 struct tracer_opt
*opt
)
3652 struct dentry
*t_options
;
3653 struct dentry
*entry
;
3655 t_options
= trace_options_init_dentry();
3659 topt
->flags
= flags
;
3662 entry
= debugfs_create_file(opt
->name
, 0644, t_options
, topt
,
3663 &trace_options_fops
);
3665 topt
->entry
= entry
;
3669 static struct trace_option_dentry
*
3670 create_trace_option_files(struct tracer
*tracer
)
3672 struct trace_option_dentry
*topts
;
3673 struct tracer_flags
*flags
;
3674 struct tracer_opt
*opts
;
3680 flags
= tracer
->flags
;
3682 if (!flags
|| !flags
->opts
)
3687 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
3690 topts
= kcalloc(cnt
+ 1, sizeof(*topts
), GFP_KERNEL
);
3694 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
3695 create_trace_option_file(&topts
[cnt
], flags
,
3702 destroy_trace_option_files(struct trace_option_dentry
*topts
)
3709 for (cnt
= 0; topts
[cnt
].opt
; cnt
++) {
3710 if (topts
[cnt
].entry
)
3711 debugfs_remove(topts
[cnt
].entry
);
3717 static struct dentry
*
3718 create_trace_option_core_file(const char *option
, long index
)
3720 struct dentry
*t_options
;
3721 struct dentry
*entry
;
3723 t_options
= trace_options_init_dentry();
3727 entry
= debugfs_create_file(option
, 0644, t_options
, (void *)index
,
3728 &trace_options_core_fops
);
3733 static __init
void create_trace_options_dir(void)
3735 struct dentry
*t_options
;
3736 struct dentry
*entry
;
3739 t_options
= trace_options_init_dentry();
3743 for (i
= 0; trace_options
[i
]; i
++) {
3744 entry
= create_trace_option_core_file(trace_options
[i
], i
);
3746 pr_warning("Could not create debugfs %s entry\n",
3751 static __init
int tracer_init_debugfs(void)
3753 struct dentry
*d_tracer
;
3754 struct dentry
*buffers
;
3755 struct dentry
*entry
;
3758 d_tracer
= tracing_init_dentry();
3760 entry
= debugfs_create_file("tracing_enabled", 0644, d_tracer
,
3761 &global_trace
, &tracing_ctrl_fops
);
3763 pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
3765 entry
= debugfs_create_file("trace_options", 0644, d_tracer
,
3766 NULL
, &tracing_iter_fops
);
3768 pr_warning("Could not create debugfs 'trace_options' entry\n");
3770 create_trace_options_dir();
3772 entry
= debugfs_create_file("tracing_cpumask", 0644, d_tracer
,
3773 NULL
, &tracing_cpumask_fops
);
3775 pr_warning("Could not create debugfs 'tracing_cpumask' entry\n");
3777 entry
= debugfs_create_file("trace", 0444, d_tracer
,
3778 (void *) TRACE_PIPE_ALL_CPU
, &tracing_fops
);
3780 pr_warning("Could not create debugfs 'trace' entry\n");
3782 entry
= debugfs_create_file("available_tracers", 0444, d_tracer
,
3783 &global_trace
, &show_traces_fops
);
3785 pr_warning("Could not create debugfs 'available_tracers' entry\n");
3787 entry
= debugfs_create_file("current_tracer", 0444, d_tracer
,
3788 &global_trace
, &set_tracer_fops
);
3790 pr_warning("Could not create debugfs 'current_tracer' entry\n");
3792 entry
= debugfs_create_file("tracing_max_latency", 0644, d_tracer
,
3793 &tracing_max_latency
,
3794 &tracing_max_lat_fops
);
3796 pr_warning("Could not create debugfs "
3797 "'tracing_max_latency' entry\n");
3799 entry
= debugfs_create_file("tracing_thresh", 0644, d_tracer
,
3800 &tracing_thresh
, &tracing_max_lat_fops
);
3802 pr_warning("Could not create debugfs "
3803 "'tracing_thresh' entry\n");
3804 entry
= debugfs_create_file("README", 0644, d_tracer
,
3805 NULL
, &tracing_readme_fops
);
3807 pr_warning("Could not create debugfs 'README' entry\n");
3809 entry
= debugfs_create_file("trace_pipe", 0444, d_tracer
,
3810 (void *) TRACE_PIPE_ALL_CPU
, &tracing_pipe_fops
);
3812 pr_warning("Could not create debugfs "
3813 "'trace_pipe' entry\n");
3815 entry
= debugfs_create_file("buffer_size_kb", 0644, d_tracer
,
3816 &global_trace
, &tracing_entries_fops
);
3818 pr_warning("Could not create debugfs "
3819 "'buffer_size_kb' entry\n");
3821 entry
= debugfs_create_file("trace_marker", 0220, d_tracer
,
3822 NULL
, &tracing_mark_fops
);
3824 pr_warning("Could not create debugfs "
3825 "'trace_marker' entry\n");
3827 buffers
= debugfs_create_dir("binary_buffers", d_tracer
);
3830 pr_warning("Could not create buffers directory\n");
3835 for_each_tracing_cpu(cpu
) {
3836 sprintf(buf
, "%d", cpu
);
3838 entry
= debugfs_create_file(buf
, 0444, buffers
,
3840 &tracing_buffers_fops
);
3842 pr_warning("Could not create debugfs buffers "
3843 "'%s' entry\n", buf
);
3847 #ifdef CONFIG_DYNAMIC_FTRACE
3848 entry
= debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
3849 &ftrace_update_tot_cnt
,
3850 &tracing_dyn_info_fops
);
3852 pr_warning("Could not create debugfs "
3853 "'dyn_ftrace_total_info' entry\n");
3855 #ifdef CONFIG_SYSPROF_TRACER
3856 init_tracer_sysprof_debugfs(d_tracer
);
3859 for_each_tracing_cpu(cpu
)
3860 tracing_init_debugfs_percpu(cpu
);
3865 static int trace_panic_handler(struct notifier_block
*this,
3866 unsigned long event
, void *unused
)
3868 if (ftrace_dump_on_oops
)
3873 static struct notifier_block trace_panic_notifier
= {
3874 .notifier_call
= trace_panic_handler
,
3876 .priority
= 150 /* priority: INT_MAX >= x >= 0 */
3879 static int trace_die_handler(struct notifier_block
*self
,
3885 if (ftrace_dump_on_oops
)
3894 static struct notifier_block trace_die_notifier
= {
3895 .notifier_call
= trace_die_handler
,
3900 * printk is set to max of 1024, we really don't need it that big.
3901 * Nothing should be printing 1000 characters anyway.
3903 #define TRACE_MAX_PRINT 1000
3906 * Define here KERN_TRACE so that we have one place to modify
3907 * it if we decide to change what log level the ftrace dump
3910 #define KERN_TRACE KERN_EMERG
3913 trace_printk_seq(struct trace_seq
*s
)
3915 /* Probably should print a warning here. */
3919 /* should be zero ended, but we are paranoid. */
3920 s
->buffer
[s
->len
] = 0;
3922 printk(KERN_TRACE
"%s", s
->buffer
);
3927 void ftrace_dump(void)
3929 static DEFINE_SPINLOCK(ftrace_dump_lock
);
3930 /* use static because iter can be a bit big for the stack */
3931 static struct trace_iterator iter
;
3932 static int dump_ran
;
3933 unsigned long flags
;
3937 spin_lock_irqsave(&ftrace_dump_lock
, flags
);
3943 /* No turning back! */
3947 for_each_tracing_cpu(cpu
) {
3948 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
3951 /* don't look at user memory in panic mode */
3952 trace_flags
&= ~TRACE_ITER_SYM_USEROBJ
;
3954 printk(KERN_TRACE
"Dumping ftrace buffer:\n");
3956 /* Simulate the iterator */
3957 iter
.tr
= &global_trace
;
3958 iter
.trace
= current_trace
;
3959 iter
.cpu_file
= TRACE_PIPE_ALL_CPU
;
3962 * We need to stop all tracing on all CPUS to read the
3963 * the next buffer. This is a bit expensive, but is
3964 * not done often. We fill all what we can read,
3965 * and then release the locks again.
3968 while (!trace_empty(&iter
)) {
3971 printk(KERN_TRACE
"---------------------------------\n");
3975 /* reset all but tr, trace, and overruns */
3976 memset(&iter
.seq
, 0,
3977 sizeof(struct trace_iterator
) -
3978 offsetof(struct trace_iterator
, seq
));
3979 iter
.iter_flags
|= TRACE_FILE_LAT_FMT
;
3982 if (find_next_entry_inc(&iter
) != NULL
) {
3983 print_trace_line(&iter
);
3984 trace_consume(&iter
);
3987 trace_printk_seq(&iter
.seq
);
3991 printk(KERN_TRACE
" (ftrace buffer empty)\n");
3993 printk(KERN_TRACE
"---------------------------------\n");
3996 spin_unlock_irqrestore(&ftrace_dump_lock
, flags
);
3999 __init
static int tracer_alloc_buffers(void)
4001 struct trace_array_cpu
*data
;
4006 if (!alloc_cpumask_var(&tracing_buffer_mask
, GFP_KERNEL
))
4009 if (!alloc_cpumask_var(&tracing_cpumask
, GFP_KERNEL
))
4010 goto out_free_buffer_mask
;
4012 if (!alloc_cpumask_var(&tracing_reader_cpumask
, GFP_KERNEL
))
4013 goto out_free_tracing_cpumask
;
4015 /* To save memory, keep the ring buffer size to its minimum */
4016 if (ring_buffer_expanded
)
4017 ring_buf_size
= trace_buf_size
;
4021 cpumask_copy(tracing_buffer_mask
, cpu_possible_mask
);
4022 cpumask_copy(tracing_cpumask
, cpu_all_mask
);
4023 cpumask_clear(tracing_reader_cpumask
);
4025 /* TODO: make the number of buffers hot pluggable with CPUS */
4026 global_trace
.buffer
= ring_buffer_alloc(ring_buf_size
,
4027 TRACE_BUFFER_FLAGS
);
4028 if (!global_trace
.buffer
) {
4029 printk(KERN_ERR
"tracer: failed to allocate ring buffer!\n");
4031 goto out_free_cpumask
;
4033 global_trace
.entries
= ring_buffer_size(global_trace
.buffer
);
4036 #ifdef CONFIG_TRACER_MAX_TRACE
4037 max_tr
.buffer
= ring_buffer_alloc(ring_buf_size
,
4038 TRACE_BUFFER_FLAGS
);
4039 if (!max_tr
.buffer
) {
4040 printk(KERN_ERR
"tracer: failed to allocate max ring buffer!\n");
4042 ring_buffer_free(global_trace
.buffer
);
4043 goto out_free_cpumask
;
4045 max_tr
.entries
= ring_buffer_size(max_tr
.buffer
);
4046 WARN_ON(max_tr
.entries
!= global_trace
.entries
);
4049 /* Allocate the first page for all buffers */
4050 for_each_tracing_cpu(i
) {
4051 data
= global_trace
.data
[i
] = &per_cpu(global_trace_cpu
, i
);
4052 max_tr
.data
[i
] = &per_cpu(max_data
, i
);
4055 trace_init_cmdlines();
4057 register_tracer(&nop_trace
);
4058 current_trace
= &nop_trace
;
4059 #ifdef CONFIG_BOOT_TRACER
4060 register_tracer(&boot_tracer
);
4062 /* All seems OK, enable tracing */
4063 tracing_disabled
= 0;
4065 atomic_notifier_chain_register(&panic_notifier_list
,
4066 &trace_panic_notifier
);
4068 register_die_notifier(&trace_die_notifier
);
4072 free_cpumask_var(tracing_reader_cpumask
);
4073 out_free_tracing_cpumask
:
4074 free_cpumask_var(tracing_cpumask
);
4075 out_free_buffer_mask
:
4076 free_cpumask_var(tracing_buffer_mask
);
4081 __init
static int clear_boot_tracer(void)
4084 * The default tracer at boot buffer is an init section.
4085 * This function is called in lateinit. If we did not
4086 * find the boot tracer, then clear it out, to prevent
4087 * later registration from accessing the buffer that is
4088 * about to be freed.
4090 if (!default_bootup_tracer
)
4093 printk(KERN_INFO
"ftrace bootup tracer '%s' not registered.\n",
4094 default_bootup_tracer
);
4095 default_bootup_tracer
= NULL
;
4100 early_initcall(tracer_alloc_buffers
);
4101 fs_initcall(tracer_init_debugfs
);
4102 late_initcall(clear_boot_tracer
);