2 * ring buffer based function tracer
4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
7 * Originally taken from the RT patch by:
8 * Arnaldo Carvalho de Melo <acme@redhat.com>
10 * Based on code from the latency_tracer, that is:
11 * Copyright (C) 2004-2006 Ingo Molnar
12 * Copyright (C) 2004 William Lee Irwin III
14 #include <linux/ring_buffer.h>
15 #include <linux/utsrelease.h>
16 #include <linux/stacktrace.h>
17 #include <linux/writeback.h>
18 #include <linux/kallsyms.h>
19 #include <linux/seq_file.h>
20 #include <linux/notifier.h>
21 #include <linux/irqflags.h>
22 #include <linux/debugfs.h>
23 #include <linux/pagemap.h>
24 #include <linux/hardirq.h>
25 #include <linux/linkage.h>
26 #include <linux/uaccess.h>
27 #include <linux/kprobes.h>
28 #include <linux/ftrace.h>
29 #include <linux/module.h>
30 #include <linux/percpu.h>
31 #include <linux/splice.h>
32 #include <linux/kdebug.h>
33 #include <linux/ctype.h>
34 #include <linux/init.h>
35 #include <linux/poll.h>
36 #include <linux/gfp.h>
40 #include "trace_output.h"
42 #define TRACE_BUFFER_FLAGS (RB_FL_OVERWRITE)
44 unsigned long __read_mostly tracing_max_latency
;
45 unsigned long __read_mostly tracing_thresh
;
48 * On boot up, the ring buffer is set to the minimum size, so that
49 * we do not waste memory on systems that are not using tracing.
51 static int ring_buffer_expanded
;
54 * We need to change this state when a selftest is running.
55 * A selftest will lurk into the ring-buffer to count the
56 * entries inserted during the selftest although some concurrent
57 * insertions into the ring-buffer such as trace_printk could occurred
58 * at the same time, giving false positive or negative results.
60 static bool __read_mostly tracing_selftest_running
;
63 * If a tracer is running, we do not want to run SELFTEST.
65 static bool __read_mostly tracing_selftest_disabled
;
67 /* For tracers that don't implement custom flags */
68 static struct tracer_opt dummy_tracer_opt
[] = {
72 static struct tracer_flags dummy_tracer_flags
= {
74 .opts
= dummy_tracer_opt
77 static int dummy_set_flag(u32 old_flags
, u32 bit
, int set
)
83 * Kill all tracing for good (never come back).
84 * It is initialized to 1 but will turn to zero if the initialization
85 * of the tracer is successful. But that is the only place that sets
88 static int tracing_disabled
= 1;
90 static DEFINE_PER_CPU(local_t
, ftrace_cpu_disabled
);
92 static inline void ftrace_disable_cpu(void)
95 local_inc(&__get_cpu_var(ftrace_cpu_disabled
));
98 static inline void ftrace_enable_cpu(void)
100 local_dec(&__get_cpu_var(ftrace_cpu_disabled
));
104 static cpumask_var_t __read_mostly tracing_buffer_mask
;
106 /* Define which cpu buffers are currently read in trace_pipe */
107 static cpumask_var_t tracing_reader_cpumask
;
109 #define for_each_tracing_cpu(cpu) \
110 for_each_cpu(cpu, tracing_buffer_mask)
113 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
115 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
116 * is set, then ftrace_dump is called. This will output the contents
117 * of the ftrace buffers to the console. This is very useful for
118 * capturing traces that lead to crashes and outputing it to a
121 * It is default off, but you can enable it with either specifying
122 * "ftrace_dump_on_oops" in the kernel command line, or setting
123 * /proc/sys/kernel/ftrace_dump_on_oops to true.
125 int ftrace_dump_on_oops
;
127 static int tracing_set_tracer(const char *buf
);
129 #define BOOTUP_TRACER_SIZE 100
130 static char bootup_tracer_buf
[BOOTUP_TRACER_SIZE
] __initdata
;
131 static char *default_bootup_tracer
;
133 static int __init
set_ftrace(char *str
)
135 strncpy(bootup_tracer_buf
, str
, BOOTUP_TRACER_SIZE
);
136 default_bootup_tracer
= bootup_tracer_buf
;
137 /* We are using ftrace early, expand it */
138 ring_buffer_expanded
= 1;
141 __setup("ftrace=", set_ftrace
);
143 static int __init
set_ftrace_dump_on_oops(char *str
)
145 ftrace_dump_on_oops
= 1;
148 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops
);
151 ns2usecs(cycle_t nsec
)
159 * The global_trace is the descriptor that holds the tracing
160 * buffers for the live tracing. For each CPU, it contains
161 * a link list of pages that will store trace entries. The
162 * page descriptor of the pages in the memory is used to hold
163 * the link list by linking the lru item in the page descriptor
164 * to each of the pages in the buffer per CPU.
166 * For each active CPU there is a data field that holds the
167 * pages for the buffer for that CPU. Each CPU has the same number
168 * of pages allocated for its buffer.
170 static struct trace_array global_trace
;
172 static DEFINE_PER_CPU(struct trace_array_cpu
, global_trace_cpu
);
174 cycle_t
ftrace_now(int cpu
)
178 /* Early boot up does not have a buffer yet */
179 if (!global_trace
.buffer
)
180 return trace_clock_local();
182 ts
= ring_buffer_time_stamp(global_trace
.buffer
, cpu
);
183 ring_buffer_normalize_time_stamp(global_trace
.buffer
, cpu
, &ts
);
189 * The max_tr is used to snapshot the global_trace when a maximum
190 * latency is reached. Some tracers will use this to store a maximum
191 * trace while it continues examining live traces.
193 * The buffers for the max_tr are set up the same as the global_trace.
194 * When a snapshot is taken, the link list of the max_tr is swapped
195 * with the link list of the global_trace and the buffers are reset for
196 * the global_trace so the tracing can continue.
198 static struct trace_array max_tr
;
200 static DEFINE_PER_CPU(struct trace_array_cpu
, max_data
);
202 /* tracer_enabled is used to toggle activation of a tracer */
203 static int tracer_enabled
= 1;
206 * tracing_is_enabled - return tracer_enabled status
208 * This function is used by other tracers to know the status
209 * of the tracer_enabled flag. Tracers may use this function
210 * to know if it should enable their features when starting
211 * up. See irqsoff tracer for an example (start_irqsoff_tracer).
213 int tracing_is_enabled(void)
215 return tracer_enabled
;
219 * trace_buf_size is the size in bytes that is allocated
220 * for a buffer. Note, the number of bytes is always rounded
223 * This number is purposely set to a low number of 16384.
224 * If the dump on oops happens, it will be much appreciated
225 * to not have to wait for all that output. Anyway this can be
226 * boot time and run time configurable.
228 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
230 static unsigned long trace_buf_size
= TRACE_BUF_SIZE_DEFAULT
;
232 /* trace_types holds a link list of available tracers. */
233 static struct tracer
*trace_types __read_mostly
;
235 /* current_trace points to the tracer that is currently active */
236 static struct tracer
*current_trace __read_mostly
;
239 * max_tracer_type_len is used to simplify the allocating of
240 * buffers to read userspace tracer names. We keep track of
241 * the longest tracer name registered.
243 static int max_tracer_type_len
;
246 * trace_types_lock is used to protect the trace_types list.
247 * This lock is also used to keep user access serialized.
248 * Accesses from userspace will grab this lock while userspace
249 * activities happen inside the kernel.
251 static DEFINE_MUTEX(trace_types_lock
);
253 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
254 static DECLARE_WAIT_QUEUE_HEAD(trace_wait
);
256 /* trace_flags holds trace_options default values */
257 unsigned long trace_flags
= TRACE_ITER_PRINT_PARENT
| TRACE_ITER_PRINTK
|
258 TRACE_ITER_ANNOTATE
| TRACE_ITER_CONTEXT_INFO
;
261 * trace_wake_up - wake up tasks waiting for trace input
263 * Simply wakes up any task that is blocked on the trace_wait
264 * queue. These is used with trace_poll for tasks polling the trace.
266 void trace_wake_up(void)
269 * The runqueue_is_locked() can fail, but this is the best we
272 if (!(trace_flags
& TRACE_ITER_BLOCK
) && !runqueue_is_locked())
273 wake_up(&trace_wait
);
276 static int __init
set_buf_size(char *str
)
278 unsigned long buf_size
;
283 ret
= strict_strtoul(str
, 0, &buf_size
);
284 /* nr_entries can not be zero */
285 if (ret
< 0 || buf_size
== 0)
287 trace_buf_size
= buf_size
;
290 __setup("trace_buf_size=", set_buf_size
);
292 unsigned long nsecs_to_usecs(unsigned long nsecs
)
297 /* These must match the bit postions in trace_iterator_flags */
298 static const char *trace_options
[] = {
323 * ftrace_max_lock is used to protect the swapping of buffers
324 * when taking a max snapshot. The buffers themselves are
325 * protected by per_cpu spinlocks. But the action of the swap
326 * needs its own lock.
328 * This is defined as a raw_spinlock_t in order to help
329 * with performance when lockdep debugging is enabled.
331 static raw_spinlock_t ftrace_max_lock
=
332 (raw_spinlock_t
)__RAW_SPIN_LOCK_UNLOCKED
;
335 * Copy the new maximum trace into the separate maximum-trace
336 * structure. (this way the maximum trace is permanently saved,
337 * for later retrieval via /debugfs/tracing/latency_trace)
340 __update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
342 struct trace_array_cpu
*data
= tr
->data
[cpu
];
345 max_tr
.time_start
= data
->preempt_timestamp
;
347 data
= max_tr
.data
[cpu
];
348 data
->saved_latency
= tracing_max_latency
;
350 memcpy(data
->comm
, tsk
->comm
, TASK_COMM_LEN
);
351 data
->pid
= tsk
->pid
;
352 data
->uid
= task_uid(tsk
);
353 data
->nice
= tsk
->static_prio
- 20 - MAX_RT_PRIO
;
354 data
->policy
= tsk
->policy
;
355 data
->rt_priority
= tsk
->rt_priority
;
357 /* record this tasks comm */
358 tracing_record_cmdline(tsk
);
361 ssize_t
trace_seq_to_user(struct trace_seq
*s
, char __user
*ubuf
, size_t cnt
)
369 if (s
->len
<= s
->readpos
)
372 len
= s
->len
- s
->readpos
;
375 ret
= copy_to_user(ubuf
, s
->buffer
+ s
->readpos
, cnt
);
385 ssize_t
trace_seq_to_buffer(struct trace_seq
*s
, void *buf
, size_t cnt
)
390 if (s
->len
<= s
->readpos
)
393 len
= s
->len
- s
->readpos
;
396 ret
= memcpy(buf
, s
->buffer
+ s
->readpos
, cnt
);
405 trace_print_seq(struct seq_file
*m
, struct trace_seq
*s
)
407 int len
= s
->len
>= PAGE_SIZE
? PAGE_SIZE
- 1 : s
->len
;
410 seq_puts(m
, s
->buffer
);
416 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
418 * @tsk: the task with the latency
419 * @cpu: The cpu that initiated the trace.
421 * Flip the buffers between the @tr and the max_tr and record information
422 * about which task was the cause of this latency.
425 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
427 struct ring_buffer
*buf
= tr
->buffer
;
429 WARN_ON_ONCE(!irqs_disabled());
430 __raw_spin_lock(&ftrace_max_lock
);
432 tr
->buffer
= max_tr
.buffer
;
435 ftrace_disable_cpu();
436 ring_buffer_reset(tr
->buffer
);
439 __update_max_tr(tr
, tsk
, cpu
);
440 __raw_spin_unlock(&ftrace_max_lock
);
444 * update_max_tr_single - only copy one trace over, and reset the rest
446 * @tsk - task with the latency
447 * @cpu - the cpu of the buffer to copy.
449 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
452 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
456 WARN_ON_ONCE(!irqs_disabled());
457 __raw_spin_lock(&ftrace_max_lock
);
459 ftrace_disable_cpu();
461 ring_buffer_reset(max_tr
.buffer
);
462 ret
= ring_buffer_swap_cpu(max_tr
.buffer
, tr
->buffer
, cpu
);
466 WARN_ON_ONCE(ret
&& ret
!= -EAGAIN
);
468 __update_max_tr(tr
, tsk
, cpu
);
469 __raw_spin_unlock(&ftrace_max_lock
);
473 * register_tracer - register a tracer with the ftrace system.
474 * @type - the plugin for the tracer
476 * Register a new plugin tracer.
478 int register_tracer(struct tracer
*type
)
479 __releases(kernel_lock
)
480 __acquires(kernel_lock
)
487 pr_info("Tracer must have a name\n");
492 * When this gets called we hold the BKL which means that
493 * preemption is disabled. Various trace selftests however
494 * need to disable and enable preemption for successful tests.
495 * So we drop the BKL here and grab it after the tests again.
498 mutex_lock(&trace_types_lock
);
500 tracing_selftest_running
= true;
502 for (t
= trace_types
; t
; t
= t
->next
) {
503 if (strcmp(type
->name
, t
->name
) == 0) {
505 pr_info("Trace %s already registered\n",
513 type
->set_flag
= &dummy_set_flag
;
515 type
->flags
= &dummy_tracer_flags
;
517 if (!type
->flags
->opts
)
518 type
->flags
->opts
= dummy_tracer_opt
;
519 if (!type
->wait_pipe
)
520 type
->wait_pipe
= default_wait_pipe
;
523 #ifdef CONFIG_FTRACE_STARTUP_TEST
524 if (type
->selftest
&& !tracing_selftest_disabled
) {
525 struct tracer
*saved_tracer
= current_trace
;
526 struct trace_array
*tr
= &global_trace
;
530 * Run a selftest on this tracer.
531 * Here we reset the trace buffer, and set the current
532 * tracer to be this tracer. The tracer can then run some
533 * internal tracing to verify that everything is in order.
534 * If we fail, we do not register this tracer.
536 for_each_tracing_cpu(i
)
537 tracing_reset(tr
, i
);
539 current_trace
= type
;
540 /* the test is responsible for initializing and enabling */
541 pr_info("Testing tracer %s: ", type
->name
);
542 ret
= type
->selftest(type
, tr
);
543 /* the test is responsible for resetting too */
544 current_trace
= saved_tracer
;
546 printk(KERN_CONT
"FAILED!\n");
549 /* Only reset on passing, to avoid touching corrupted buffers */
550 for_each_tracing_cpu(i
)
551 tracing_reset(tr
, i
);
553 printk(KERN_CONT
"PASSED\n");
557 type
->next
= trace_types
;
559 len
= strlen(type
->name
);
560 if (len
> max_tracer_type_len
)
561 max_tracer_type_len
= len
;
564 tracing_selftest_running
= false;
565 mutex_unlock(&trace_types_lock
);
567 if (ret
|| !default_bootup_tracer
)
570 if (strncmp(default_bootup_tracer
, type
->name
, BOOTUP_TRACER_SIZE
))
573 printk(KERN_INFO
"Starting tracer '%s'\n", type
->name
);
574 /* Do we want this tracer to start on bootup? */
575 tracing_set_tracer(type
->name
);
576 default_bootup_tracer
= NULL
;
577 /* disable other selftests, since this will break it. */
578 tracing_selftest_disabled
= 1;
579 #ifdef CONFIG_FTRACE_STARTUP_TEST
580 printk(KERN_INFO
"Disabling FTRACE selftests due to running tracer '%s'\n",
589 void unregister_tracer(struct tracer
*type
)
594 mutex_lock(&trace_types_lock
);
595 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
599 pr_info("Trace %s not registered\n", type
->name
);
605 if (type
== current_trace
&& tracer_enabled
) {
608 if (current_trace
->stop
)
609 current_trace
->stop(&global_trace
);
610 current_trace
= &nop_trace
;
613 if (strlen(type
->name
) != max_tracer_type_len
)
616 max_tracer_type_len
= 0;
617 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
618 len
= strlen((*t
)->name
);
619 if (len
> max_tracer_type_len
)
620 max_tracer_type_len
= len
;
623 mutex_unlock(&trace_types_lock
);
626 void tracing_reset(struct trace_array
*tr
, int cpu
)
628 ftrace_disable_cpu();
629 ring_buffer_reset_cpu(tr
->buffer
, cpu
);
633 void tracing_reset_online_cpus(struct trace_array
*tr
)
637 tr
->time_start
= ftrace_now(tr
->cpu
);
639 for_each_online_cpu(cpu
)
640 tracing_reset(tr
, cpu
);
643 #define SAVED_CMDLINES 128
644 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
645 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
646 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
647 static int cmdline_idx
;
648 static raw_spinlock_t trace_cmdline_lock
= __RAW_SPIN_LOCK_UNLOCKED
;
650 /* temporary disable recording */
651 static atomic_t trace_record_cmdline_disabled __read_mostly
;
653 static void trace_init_cmdlines(void)
655 memset(&map_pid_to_cmdline
, -1, sizeof(map_pid_to_cmdline
));
656 memset(&map_cmdline_to_pid
, -1, sizeof(map_cmdline_to_pid
));
660 static int trace_stop_count
;
661 static DEFINE_SPINLOCK(tracing_start_lock
);
664 * ftrace_off_permanent - disable all ftrace code permanently
666 * This should only be called when a serious anomally has
667 * been detected. This will turn off the function tracing,
668 * ring buffers, and other tracing utilites. It takes no
669 * locks and can be called from any context.
671 void ftrace_off_permanent(void)
673 tracing_disabled
= 1;
675 tracing_off_permanent();
679 * tracing_start - quick start of the tracer
681 * If tracing is enabled but was stopped by tracing_stop,
682 * this will start the tracer back up.
684 void tracing_start(void)
686 struct ring_buffer
*buffer
;
689 if (tracing_disabled
)
692 spin_lock_irqsave(&tracing_start_lock
, flags
);
693 if (--trace_stop_count
) {
694 if (trace_stop_count
< 0) {
695 /* Someone screwed up their debugging */
697 trace_stop_count
= 0;
703 buffer
= global_trace
.buffer
;
705 ring_buffer_record_enable(buffer
);
707 buffer
= max_tr
.buffer
;
709 ring_buffer_record_enable(buffer
);
713 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
717 * tracing_stop - quick stop of the tracer
719 * Light weight way to stop tracing. Use in conjunction with
722 void tracing_stop(void)
724 struct ring_buffer
*buffer
;
728 spin_lock_irqsave(&tracing_start_lock
, flags
);
729 if (trace_stop_count
++)
732 buffer
= global_trace
.buffer
;
734 ring_buffer_record_disable(buffer
);
736 buffer
= max_tr
.buffer
;
738 ring_buffer_record_disable(buffer
);
741 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
744 void trace_stop_cmdline_recording(void);
746 static void trace_save_cmdline(struct task_struct
*tsk
)
751 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
755 * It's not the end of the world if we don't get
756 * the lock, but we also don't want to spin
757 * nor do we want to disable interrupts,
758 * so if we miss here, then better luck next time.
760 if (!__raw_spin_trylock(&trace_cmdline_lock
))
763 idx
= map_pid_to_cmdline
[tsk
->pid
];
764 if (idx
>= SAVED_CMDLINES
) {
765 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
767 map
= map_cmdline_to_pid
[idx
];
768 if (map
<= PID_MAX_DEFAULT
)
769 map_pid_to_cmdline
[map
] = (unsigned)-1;
771 map_pid_to_cmdline
[tsk
->pid
] = idx
;
776 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
778 __raw_spin_unlock(&trace_cmdline_lock
);
781 void trace_find_cmdline(int pid
, char comm
[])
786 strcpy(comm
, "<idle>");
790 if (pid
> PID_MAX_DEFAULT
) {
791 strcpy(comm
, "<...>");
795 __raw_spin_lock(&trace_cmdline_lock
);
796 map
= map_pid_to_cmdline
[pid
];
797 if (map
>= SAVED_CMDLINES
)
800 strcpy(comm
, saved_cmdlines
[map
]);
803 __raw_spin_unlock(&trace_cmdline_lock
);
806 void tracing_record_cmdline(struct task_struct
*tsk
)
808 if (atomic_read(&trace_record_cmdline_disabled
) || !tracing_is_on())
811 trace_save_cmdline(tsk
);
815 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
,
818 struct task_struct
*tsk
= current
;
820 entry
->preempt_count
= pc
& 0xff;
821 entry
->pid
= (tsk
) ? tsk
->pid
: 0;
822 entry
->tgid
= (tsk
) ? tsk
->tgid
: 0;
824 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
825 (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
827 TRACE_FLAG_IRQS_NOSUPPORT
|
829 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
830 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
831 (need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0);
834 struct ring_buffer_event
*trace_buffer_lock_reserve(struct trace_array
*tr
,
837 unsigned long flags
, int pc
)
839 struct ring_buffer_event
*event
;
841 event
= ring_buffer_lock_reserve(tr
->buffer
, len
);
843 struct trace_entry
*ent
= ring_buffer_event_data(event
);
845 tracing_generic_entry_update(ent
, flags
, pc
);
851 static void ftrace_trace_stack(struct trace_array
*tr
,
852 unsigned long flags
, int skip
, int pc
);
853 static void ftrace_trace_userstack(struct trace_array
*tr
,
854 unsigned long flags
, int pc
);
856 void trace_buffer_unlock_commit(struct trace_array
*tr
,
857 struct ring_buffer_event
*event
,
858 unsigned long flags
, int pc
)
860 ring_buffer_unlock_commit(tr
->buffer
, event
);
862 ftrace_trace_stack(tr
, flags
, 6, pc
);
863 ftrace_trace_userstack(tr
, flags
, pc
);
867 struct ring_buffer_event
*
868 trace_current_buffer_lock_reserve(unsigned char type
, unsigned long len
,
869 unsigned long flags
, int pc
)
871 return trace_buffer_lock_reserve(&global_trace
,
872 type
, len
, flags
, pc
);
875 void trace_current_buffer_unlock_commit(struct ring_buffer_event
*event
,
876 unsigned long flags
, int pc
)
878 return trace_buffer_unlock_commit(&global_trace
, event
, flags
, pc
);
882 trace_function(struct trace_array
*tr
,
883 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
886 struct ring_buffer_event
*event
;
887 struct ftrace_entry
*entry
;
889 /* If we are reading the ring buffer, don't trace */
890 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
893 event
= trace_buffer_lock_reserve(tr
, TRACE_FN
, sizeof(*entry
),
897 entry
= ring_buffer_event_data(event
);
899 entry
->parent_ip
= parent_ip
;
900 ring_buffer_unlock_commit(tr
->buffer
, event
);
903 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
904 static void __trace_graph_entry(struct trace_array
*tr
,
905 struct ftrace_graph_ent
*trace
,
909 struct ring_buffer_event
*event
;
910 struct ftrace_graph_ent_entry
*entry
;
912 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
915 event
= trace_buffer_lock_reserve(&global_trace
, TRACE_GRAPH_ENT
,
916 sizeof(*entry
), flags
, pc
);
919 entry
= ring_buffer_event_data(event
);
920 entry
->graph_ent
= *trace
;
921 ring_buffer_unlock_commit(global_trace
.buffer
, event
);
924 static void __trace_graph_return(struct trace_array
*tr
,
925 struct ftrace_graph_ret
*trace
,
929 struct ring_buffer_event
*event
;
930 struct ftrace_graph_ret_entry
*entry
;
932 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
935 event
= trace_buffer_lock_reserve(&global_trace
, TRACE_GRAPH_RET
,
936 sizeof(*entry
), flags
, pc
);
939 entry
= ring_buffer_event_data(event
);
941 ring_buffer_unlock_commit(global_trace
.buffer
, event
);
946 ftrace(struct trace_array
*tr
, struct trace_array_cpu
*data
,
947 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
950 if (likely(!atomic_read(&data
->disabled
)))
951 trace_function(tr
, ip
, parent_ip
, flags
, pc
);
954 static void __ftrace_trace_stack(struct trace_array
*tr
,
958 #ifdef CONFIG_STACKTRACE
959 struct ring_buffer_event
*event
;
960 struct stack_entry
*entry
;
961 struct stack_trace trace
;
963 event
= trace_buffer_lock_reserve(tr
, TRACE_STACK
,
964 sizeof(*entry
), flags
, pc
);
967 entry
= ring_buffer_event_data(event
);
968 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
970 trace
.nr_entries
= 0;
971 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
973 trace
.entries
= entry
->caller
;
975 save_stack_trace(&trace
);
976 ring_buffer_unlock_commit(tr
->buffer
, event
);
980 static void ftrace_trace_stack(struct trace_array
*tr
,
984 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
987 __ftrace_trace_stack(tr
, flags
, skip
, pc
);
990 void __trace_stack(struct trace_array
*tr
,
994 __ftrace_trace_stack(tr
, flags
, skip
, pc
);
997 static void ftrace_trace_userstack(struct trace_array
*tr
,
998 unsigned long flags
, int pc
)
1000 #ifdef CONFIG_STACKTRACE
1001 struct ring_buffer_event
*event
;
1002 struct userstack_entry
*entry
;
1003 struct stack_trace trace
;
1005 if (!(trace_flags
& TRACE_ITER_USERSTACKTRACE
))
1008 event
= trace_buffer_lock_reserve(tr
, TRACE_USER_STACK
,
1009 sizeof(*entry
), flags
, pc
);
1012 entry
= ring_buffer_event_data(event
);
1014 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
1016 trace
.nr_entries
= 0;
1017 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1019 trace
.entries
= entry
->caller
;
1021 save_stack_trace_user(&trace
);
1022 ring_buffer_unlock_commit(tr
->buffer
, event
);
1027 static void __trace_userstack(struct trace_array
*tr
, unsigned long flags
)
1029 ftrace_trace_userstack(tr
, flags
, preempt_count());
1034 ftrace_trace_special(void *__tr
,
1035 unsigned long arg1
, unsigned long arg2
, unsigned long arg3
,
1038 struct ring_buffer_event
*event
;
1039 struct trace_array
*tr
= __tr
;
1040 struct special_entry
*entry
;
1042 event
= trace_buffer_lock_reserve(tr
, TRACE_SPECIAL
,
1043 sizeof(*entry
), 0, pc
);
1046 entry
= ring_buffer_event_data(event
);
1050 trace_buffer_unlock_commit(tr
, event
, 0, pc
);
1054 __trace_special(void *__tr
, void *__data
,
1055 unsigned long arg1
, unsigned long arg2
, unsigned long arg3
)
1057 ftrace_trace_special(__tr
, arg1
, arg2
, arg3
, preempt_count());
1061 tracing_sched_switch_trace(struct trace_array
*tr
,
1062 struct task_struct
*prev
,
1063 struct task_struct
*next
,
1064 unsigned long flags
, int pc
)
1066 struct ring_buffer_event
*event
;
1067 struct ctx_switch_entry
*entry
;
1069 event
= trace_buffer_lock_reserve(tr
, TRACE_CTX
,
1070 sizeof(*entry
), flags
, pc
);
1073 entry
= ring_buffer_event_data(event
);
1074 entry
->prev_pid
= prev
->pid
;
1075 entry
->prev_prio
= prev
->prio
;
1076 entry
->prev_state
= prev
->state
;
1077 entry
->next_pid
= next
->pid
;
1078 entry
->next_prio
= next
->prio
;
1079 entry
->next_state
= next
->state
;
1080 entry
->next_cpu
= task_cpu(next
);
1081 trace_buffer_unlock_commit(tr
, event
, flags
, pc
);
1085 tracing_sched_wakeup_trace(struct trace_array
*tr
,
1086 struct task_struct
*wakee
,
1087 struct task_struct
*curr
,
1088 unsigned long flags
, int pc
)
1090 struct ring_buffer_event
*event
;
1091 struct ctx_switch_entry
*entry
;
1093 event
= trace_buffer_lock_reserve(tr
, TRACE_WAKE
,
1094 sizeof(*entry
), flags
, pc
);
1097 entry
= ring_buffer_event_data(event
);
1098 entry
->prev_pid
= curr
->pid
;
1099 entry
->prev_prio
= curr
->prio
;
1100 entry
->prev_state
= curr
->state
;
1101 entry
->next_pid
= wakee
->pid
;
1102 entry
->next_prio
= wakee
->prio
;
1103 entry
->next_state
= wakee
->state
;
1104 entry
->next_cpu
= task_cpu(wakee
);
1106 ring_buffer_unlock_commit(tr
->buffer
, event
);
1107 ftrace_trace_stack(tr
, flags
, 6, pc
);
1108 ftrace_trace_userstack(tr
, flags
, pc
);
1112 ftrace_special(unsigned long arg1
, unsigned long arg2
, unsigned long arg3
)
1114 struct trace_array
*tr
= &global_trace
;
1115 struct trace_array_cpu
*data
;
1116 unsigned long flags
;
1120 if (tracing_disabled
)
1123 pc
= preempt_count();
1124 local_irq_save(flags
);
1125 cpu
= raw_smp_processor_id();
1126 data
= tr
->data
[cpu
];
1128 if (likely(atomic_inc_return(&data
->disabled
) == 1))
1129 ftrace_trace_special(tr
, arg1
, arg2
, arg3
, pc
);
1131 atomic_dec(&data
->disabled
);
1132 local_irq_restore(flags
);
1135 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1136 int trace_graph_entry(struct ftrace_graph_ent
*trace
)
1138 struct trace_array
*tr
= &global_trace
;
1139 struct trace_array_cpu
*data
;
1140 unsigned long flags
;
1145 if (!ftrace_trace_task(current
))
1148 if (!ftrace_graph_addr(trace
->func
))
1151 local_irq_save(flags
);
1152 cpu
= raw_smp_processor_id();
1153 data
= tr
->data
[cpu
];
1154 disabled
= atomic_inc_return(&data
->disabled
);
1155 if (likely(disabled
== 1)) {
1156 pc
= preempt_count();
1157 __trace_graph_entry(tr
, trace
, flags
, pc
);
1159 /* Only do the atomic if it is not already set */
1160 if (!test_tsk_trace_graph(current
))
1161 set_tsk_trace_graph(current
);
1162 atomic_dec(&data
->disabled
);
1163 local_irq_restore(flags
);
1168 void trace_graph_return(struct ftrace_graph_ret
*trace
)
1170 struct trace_array
*tr
= &global_trace
;
1171 struct trace_array_cpu
*data
;
1172 unsigned long flags
;
1177 local_irq_save(flags
);
1178 cpu
= raw_smp_processor_id();
1179 data
= tr
->data
[cpu
];
1180 disabled
= atomic_inc_return(&data
->disabled
);
1181 if (likely(disabled
== 1)) {
1182 pc
= preempt_count();
1183 __trace_graph_return(tr
, trace
, flags
, pc
);
1186 clear_tsk_trace_graph(current
);
1187 atomic_dec(&data
->disabled
);
1188 local_irq_restore(flags
);
1190 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1194 * trace_vbprintk - write binary msg to tracing buffer
1197 int trace_vbprintk(unsigned long ip
, int depth
, const char *fmt
, va_list args
)
1199 static raw_spinlock_t trace_buf_lock
=
1200 (raw_spinlock_t
)__RAW_SPIN_LOCK_UNLOCKED
;
1201 static u32 trace_buf
[TRACE_BUF_SIZE
];
1203 struct ring_buffer_event
*event
;
1204 struct trace_array
*tr
= &global_trace
;
1205 struct trace_array_cpu
*data
;
1206 struct bprint_entry
*entry
;
1207 unsigned long flags
;
1209 int cpu
, len
= 0, size
, pc
;
1211 if (unlikely(tracing_selftest_running
|| tracing_disabled
))
1214 /* Don't pollute graph traces with trace_vprintk internals */
1215 pause_graph_tracing();
1217 pc
= preempt_count();
1218 resched
= ftrace_preempt_disable();
1219 cpu
= raw_smp_processor_id();
1220 data
= tr
->data
[cpu
];
1222 if (unlikely(atomic_read(&data
->disabled
)))
1225 /* Lockdep uses trace_printk for lock tracing */
1226 local_irq_save(flags
);
1227 __raw_spin_lock(&trace_buf_lock
);
1228 len
= vbin_printf(trace_buf
, TRACE_BUF_SIZE
, fmt
, args
);
1230 if (len
> TRACE_BUF_SIZE
|| len
< 0)
1233 size
= sizeof(*entry
) + sizeof(u32
) * len
;
1234 event
= trace_buffer_lock_reserve(tr
, TRACE_BPRINT
, size
, flags
, pc
);
1237 entry
= ring_buffer_event_data(event
);
1239 entry
->depth
= depth
;
1242 memcpy(entry
->buf
, trace_buf
, sizeof(u32
) * len
);
1243 ring_buffer_unlock_commit(tr
->buffer
, event
);
1246 __raw_spin_unlock(&trace_buf_lock
);
1247 local_irq_restore(flags
);
1250 ftrace_preempt_enable(resched
);
1251 unpause_graph_tracing();
1255 EXPORT_SYMBOL_GPL(trace_vbprintk
);
1257 int trace_vprintk(unsigned long ip
, int depth
, const char *fmt
, va_list args
)
1259 static raw_spinlock_t trace_buf_lock
= __RAW_SPIN_LOCK_UNLOCKED
;
1260 static char trace_buf
[TRACE_BUF_SIZE
];
1262 struct ring_buffer_event
*event
;
1263 struct trace_array
*tr
= &global_trace
;
1264 struct trace_array_cpu
*data
;
1265 int cpu
, len
= 0, size
, pc
;
1266 struct print_entry
*entry
;
1267 unsigned long irq_flags
;
1269 if (tracing_disabled
|| tracing_selftest_running
)
1272 pc
= preempt_count();
1273 preempt_disable_notrace();
1274 cpu
= raw_smp_processor_id();
1275 data
= tr
->data
[cpu
];
1277 if (unlikely(atomic_read(&data
->disabled
)))
1280 pause_graph_tracing();
1281 raw_local_irq_save(irq_flags
);
1282 __raw_spin_lock(&trace_buf_lock
);
1283 len
= vsnprintf(trace_buf
, TRACE_BUF_SIZE
, fmt
, args
);
1285 len
= min(len
, TRACE_BUF_SIZE
-1);
1288 size
= sizeof(*entry
) + len
+ 1;
1289 event
= trace_buffer_lock_reserve(tr
, TRACE_PRINT
, size
, irq_flags
, pc
);
1292 entry
= ring_buffer_event_data(event
);
1294 entry
->depth
= depth
;
1296 memcpy(&entry
->buf
, trace_buf
, len
);
1297 entry
->buf
[len
] = 0;
1298 ring_buffer_unlock_commit(tr
->buffer
, event
);
1301 __raw_spin_unlock(&trace_buf_lock
);
1302 raw_local_irq_restore(irq_flags
);
1303 unpause_graph_tracing();
1305 preempt_enable_notrace();
1309 EXPORT_SYMBOL_GPL(trace_vprintk
);
1311 enum trace_file_type
{
1312 TRACE_FILE_LAT_FMT
= 1,
1313 TRACE_FILE_ANNOTATE
= 2,
1316 static void trace_iterator_increment(struct trace_iterator
*iter
)
1318 /* Don't allow ftrace to trace into the ring buffers */
1319 ftrace_disable_cpu();
1322 if (iter
->buffer_iter
[iter
->cpu
])
1323 ring_buffer_read(iter
->buffer_iter
[iter
->cpu
], NULL
);
1325 ftrace_enable_cpu();
1328 static struct trace_entry
*
1329 peek_next_entry(struct trace_iterator
*iter
, int cpu
, u64
*ts
)
1331 struct ring_buffer_event
*event
;
1332 struct ring_buffer_iter
*buf_iter
= iter
->buffer_iter
[cpu
];
1334 /* Don't allow ftrace to trace into the ring buffers */
1335 ftrace_disable_cpu();
1338 event
= ring_buffer_iter_peek(buf_iter
, ts
);
1340 event
= ring_buffer_peek(iter
->tr
->buffer
, cpu
, ts
);
1342 ftrace_enable_cpu();
1344 return event
? ring_buffer_event_data(event
) : NULL
;
1347 static struct trace_entry
*
1348 __find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
, u64
*ent_ts
)
1350 struct ring_buffer
*buffer
= iter
->tr
->buffer
;
1351 struct trace_entry
*ent
, *next
= NULL
;
1352 int cpu_file
= iter
->cpu_file
;
1353 u64 next_ts
= 0, ts
;
1358 * If we are in a per_cpu trace file, don't bother by iterating over
1359 * all cpu and peek directly.
1361 if (cpu_file
> TRACE_PIPE_ALL_CPU
) {
1362 if (ring_buffer_empty_cpu(buffer
, cpu_file
))
1364 ent
= peek_next_entry(iter
, cpu_file
, ent_ts
);
1366 *ent_cpu
= cpu_file
;
1371 for_each_tracing_cpu(cpu
) {
1373 if (ring_buffer_empty_cpu(buffer
, cpu
))
1376 ent
= peek_next_entry(iter
, cpu
, &ts
);
1379 * Pick the entry with the smallest timestamp:
1381 if (ent
&& (!next
|| ts
< next_ts
)) {
1389 *ent_cpu
= next_cpu
;
1397 /* Find the next real entry, without updating the iterator itself */
1398 struct trace_entry
*trace_find_next_entry(struct trace_iterator
*iter
,
1399 int *ent_cpu
, u64
*ent_ts
)
1401 return __find_next_entry(iter
, ent_cpu
, ent_ts
);
1404 /* Find the next real entry, and increment the iterator to the next entry */
1405 static void *find_next_entry_inc(struct trace_iterator
*iter
)
1407 iter
->ent
= __find_next_entry(iter
, &iter
->cpu
, &iter
->ts
);
1410 trace_iterator_increment(iter
);
1412 return iter
->ent
? iter
: NULL
;
1415 static void trace_consume(struct trace_iterator
*iter
)
1417 /* Don't allow ftrace to trace into the ring buffers */
1418 ftrace_disable_cpu();
1419 ring_buffer_consume(iter
->tr
->buffer
, iter
->cpu
, &iter
->ts
);
1420 ftrace_enable_cpu();
1423 static void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1425 struct trace_iterator
*iter
= m
->private;
1431 /* can't go backwards */
1436 ent
= find_next_entry_inc(iter
);
1440 while (ent
&& iter
->idx
< i
)
1441 ent
= find_next_entry_inc(iter
);
1449 * No necessary locking here. The worst thing which can
1450 * happen is loosing events consumed at the same time
1451 * by a trace_pipe reader.
1452 * Other than that, we don't risk to crash the ring buffer
1453 * because it serializes the readers.
1455 * The current tracer is copied to avoid a global locking
1458 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
1460 struct trace_iterator
*iter
= m
->private;
1461 static struct tracer
*old_tracer
;
1462 int cpu_file
= iter
->cpu_file
;
1467 /* copy the tracer to avoid using a global lock all around */
1468 mutex_lock(&trace_types_lock
);
1469 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
1470 old_tracer
= current_trace
;
1471 *iter
->trace
= *current_trace
;
1473 mutex_unlock(&trace_types_lock
);
1475 atomic_inc(&trace_record_cmdline_disabled
);
1477 if (*pos
!= iter
->pos
) {
1482 ftrace_disable_cpu();
1484 if (cpu_file
== TRACE_PIPE_ALL_CPU
) {
1485 for_each_tracing_cpu(cpu
)
1486 ring_buffer_iter_reset(iter
->buffer_iter
[cpu
]);
1488 ring_buffer_iter_reset(iter
->buffer_iter
[cpu_file
]);
1491 ftrace_enable_cpu();
1493 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
1498 p
= s_next(m
, p
, &l
);
1504 static void s_stop(struct seq_file
*m
, void *p
)
1506 atomic_dec(&trace_record_cmdline_disabled
);
1509 static void print_lat_help_header(struct seq_file
*m
)
1511 seq_puts(m
, "# _------=> CPU# \n");
1512 seq_puts(m
, "# / _-----=> irqs-off \n");
1513 seq_puts(m
, "# | / _----=> need-resched \n");
1514 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
1515 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
1516 seq_puts(m
, "# |||| / \n");
1517 seq_puts(m
, "# ||||| delay \n");
1518 seq_puts(m
, "# cmd pid ||||| time | caller \n");
1519 seq_puts(m
, "# \\ / ||||| \\ | / \n");
1522 static void print_func_help_header(struct seq_file
*m
)
1524 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1525 seq_puts(m
, "# | | | | |\n");
1530 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
1532 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1533 struct trace_array
*tr
= iter
->tr
;
1534 struct trace_array_cpu
*data
= tr
->data
[tr
->cpu
];
1535 struct tracer
*type
= current_trace
;
1536 unsigned long total
;
1537 unsigned long entries
;
1538 const char *name
= "preemption";
1543 entries
= ring_buffer_entries(iter
->tr
->buffer
);
1545 ring_buffer_overruns(iter
->tr
->buffer
);
1547 seq_printf(m
, "# %s latency trace v1.1.5 on %s\n",
1549 seq_puts(m
, "# -----------------------------------"
1550 "---------------------------------\n");
1551 seq_printf(m
, "# latency: %lu us, #%lu/%lu, CPU#%d |"
1552 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1553 nsecs_to_usecs(data
->saved_latency
),
1557 #if defined(CONFIG_PREEMPT_NONE)
1559 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1561 #elif defined(CONFIG_PREEMPT)
1566 /* These are reserved for later use */
1569 seq_printf(m
, " #P:%d)\n", num_online_cpus());
1573 seq_puts(m
, "# -----------------\n");
1574 seq_printf(m
, "# | task: %.16s-%d "
1575 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1576 data
->comm
, data
->pid
, data
->uid
, data
->nice
,
1577 data
->policy
, data
->rt_priority
);
1578 seq_puts(m
, "# -----------------\n");
1580 if (data
->critical_start
) {
1581 seq_puts(m
, "# => started at: ");
1582 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
1583 trace_print_seq(m
, &iter
->seq
);
1584 seq_puts(m
, "\n# => ended at: ");
1585 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
1586 trace_print_seq(m
, &iter
->seq
);
1593 static void test_cpu_buff_start(struct trace_iterator
*iter
)
1595 struct trace_seq
*s
= &iter
->seq
;
1597 if (!(trace_flags
& TRACE_ITER_ANNOTATE
))
1600 if (!(iter
->iter_flags
& TRACE_FILE_ANNOTATE
))
1603 if (cpumask_test_cpu(iter
->cpu
, iter
->started
))
1606 cpumask_set_cpu(iter
->cpu
, iter
->started
);
1607 trace_seq_printf(s
, "##### CPU %u buffer started ####\n", iter
->cpu
);
1610 static enum print_line_t
print_trace_fmt(struct trace_iterator
*iter
)
1612 struct trace_seq
*s
= &iter
->seq
;
1613 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1614 struct trace_entry
*entry
;
1615 struct trace_event
*event
;
1619 test_cpu_buff_start(iter
);
1621 event
= ftrace_find_event(entry
->type
);
1623 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1624 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
1625 if (!trace_print_lat_context(iter
))
1628 if (!trace_print_context(iter
))
1634 return event
->trace(iter
, sym_flags
);
1636 if (!trace_seq_printf(s
, "Unknown type %d\n", entry
->type
))
1639 return TRACE_TYPE_HANDLED
;
1641 return TRACE_TYPE_PARTIAL_LINE
;
1644 static enum print_line_t
print_raw_fmt(struct trace_iterator
*iter
)
1646 struct trace_seq
*s
= &iter
->seq
;
1647 struct trace_entry
*entry
;
1648 struct trace_event
*event
;
1652 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1653 if (!trace_seq_printf(s
, "%d %d %llu ",
1654 entry
->pid
, iter
->cpu
, iter
->ts
))
1658 event
= ftrace_find_event(entry
->type
);
1660 return event
->raw(iter
, 0);
1662 if (!trace_seq_printf(s
, "%d ?\n", entry
->type
))
1665 return TRACE_TYPE_HANDLED
;
1667 return TRACE_TYPE_PARTIAL_LINE
;
1670 static enum print_line_t
print_hex_fmt(struct trace_iterator
*iter
)
1672 struct trace_seq
*s
= &iter
->seq
;
1673 unsigned char newline
= '\n';
1674 struct trace_entry
*entry
;
1675 struct trace_event
*event
;
1679 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1680 SEQ_PUT_HEX_FIELD_RET(s
, entry
->pid
);
1681 SEQ_PUT_HEX_FIELD_RET(s
, iter
->cpu
);
1682 SEQ_PUT_HEX_FIELD_RET(s
, iter
->ts
);
1685 event
= ftrace_find_event(entry
->type
);
1687 enum print_line_t ret
= event
->hex(iter
, 0);
1688 if (ret
!= TRACE_TYPE_HANDLED
)
1692 SEQ_PUT_FIELD_RET(s
, newline
);
1694 return TRACE_TYPE_HANDLED
;
1697 static enum print_line_t
print_bprintk_msg_only(struct trace_iterator
*iter
)
1699 struct trace_seq
*s
= &iter
->seq
;
1700 struct trace_entry
*entry
= iter
->ent
;
1701 struct bprint_entry
*field
;
1704 trace_assign_type(field
, entry
);
1706 ret
= trace_seq_bprintf(s
, field
->fmt
, field
->buf
);
1708 return TRACE_TYPE_PARTIAL_LINE
;
1710 return TRACE_TYPE_HANDLED
;
1713 static enum print_line_t
print_printk_msg_only(struct trace_iterator
*iter
)
1715 struct trace_seq
*s
= &iter
->seq
;
1716 struct trace_entry
*entry
= iter
->ent
;
1717 struct print_entry
*field
;
1720 trace_assign_type(field
, entry
);
1722 ret
= trace_seq_printf(s
, "%s", field
->buf
);
1724 return TRACE_TYPE_PARTIAL_LINE
;
1726 return TRACE_TYPE_HANDLED
;
1729 static enum print_line_t
print_bin_fmt(struct trace_iterator
*iter
)
1731 struct trace_seq
*s
= &iter
->seq
;
1732 struct trace_entry
*entry
;
1733 struct trace_event
*event
;
1737 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1738 SEQ_PUT_FIELD_RET(s
, entry
->pid
);
1739 SEQ_PUT_FIELD_RET(s
, iter
->cpu
);
1740 SEQ_PUT_FIELD_RET(s
, iter
->ts
);
1743 event
= ftrace_find_event(entry
->type
);
1744 return event
? event
->binary(iter
, 0) : TRACE_TYPE_HANDLED
;
1747 static int trace_empty(struct trace_iterator
*iter
)
1751 /* If we are looking at one CPU buffer, only check that one */
1752 if (iter
->cpu_file
!= TRACE_PIPE_ALL_CPU
) {
1753 cpu
= iter
->cpu_file
;
1754 if (iter
->buffer_iter
[cpu
]) {
1755 if (!ring_buffer_iter_empty(iter
->buffer_iter
[cpu
]))
1758 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
1764 for_each_tracing_cpu(cpu
) {
1765 if (iter
->buffer_iter
[cpu
]) {
1766 if (!ring_buffer_iter_empty(iter
->buffer_iter
[cpu
]))
1769 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
1777 static enum print_line_t
print_trace_line(struct trace_iterator
*iter
)
1779 enum print_line_t ret
;
1781 if (iter
->trace
&& iter
->trace
->print_line
) {
1782 ret
= iter
->trace
->print_line(iter
);
1783 if (ret
!= TRACE_TYPE_UNHANDLED
)
1787 if (iter
->ent
->type
== TRACE_BPRINT
&&
1788 trace_flags
& TRACE_ITER_PRINTK
&&
1789 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
1790 return print_bprintk_msg_only(iter
);
1792 if (iter
->ent
->type
== TRACE_PRINT
&&
1793 trace_flags
& TRACE_ITER_PRINTK
&&
1794 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
1795 return print_printk_msg_only(iter
);
1797 if (trace_flags
& TRACE_ITER_BIN
)
1798 return print_bin_fmt(iter
);
1800 if (trace_flags
& TRACE_ITER_HEX
)
1801 return print_hex_fmt(iter
);
1803 if (trace_flags
& TRACE_ITER_RAW
)
1804 return print_raw_fmt(iter
);
1806 return print_trace_fmt(iter
);
1809 static int s_show(struct seq_file
*m
, void *v
)
1811 struct trace_iterator
*iter
= v
;
1813 if (iter
->ent
== NULL
) {
1815 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
1818 if (iter
->trace
&& iter
->trace
->print_header
)
1819 iter
->trace
->print_header(m
);
1820 else if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
1821 /* print nothing if the buffers are empty */
1822 if (trace_empty(iter
))
1824 print_trace_header(m
, iter
);
1825 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1826 print_lat_help_header(m
);
1828 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1829 print_func_help_header(m
);
1832 print_trace_line(iter
);
1833 trace_print_seq(m
, &iter
->seq
);
1839 static struct seq_operations tracer_seq_ops
= {
1846 static struct trace_iterator
*
1847 __tracing_open(struct inode
*inode
, struct file
*file
)
1849 long cpu_file
= (long) inode
->i_private
;
1850 void *fail_ret
= ERR_PTR(-ENOMEM
);
1851 struct trace_iterator
*iter
;
1855 if (tracing_disabled
)
1856 return ERR_PTR(-ENODEV
);
1858 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
1860 return ERR_PTR(-ENOMEM
);
1863 * We make a copy of the current tracer to avoid concurrent
1864 * changes on it while we are reading.
1866 mutex_lock(&trace_types_lock
);
1867 iter
->trace
= kzalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
1872 *iter
->trace
= *current_trace
;
1874 if (current_trace
&& current_trace
->print_max
)
1877 iter
->tr
= &global_trace
;
1879 mutex_init(&iter
->mutex
);
1880 iter
->cpu_file
= cpu_file
;
1882 /* Notify the tracer early; before we stop tracing. */
1883 if (iter
->trace
&& iter
->trace
->open
)
1884 iter
->trace
->open(iter
);
1886 /* Annotate start of buffers if we had overruns */
1887 if (ring_buffer_overruns(iter
->tr
->buffer
))
1888 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
1890 if (iter
->cpu_file
== TRACE_PIPE_ALL_CPU
) {
1891 for_each_tracing_cpu(cpu
) {
1893 iter
->buffer_iter
[cpu
] =
1894 ring_buffer_read_start(iter
->tr
->buffer
, cpu
);
1897 cpu
= iter
->cpu_file
;
1898 iter
->buffer_iter
[cpu
] =
1899 ring_buffer_read_start(iter
->tr
->buffer
, cpu
);
1902 /* TODO stop tracer */
1903 ret
= seq_open(file
, &tracer_seq_ops
);
1905 fail_ret
= ERR_PTR(ret
);
1909 m
= file
->private_data
;
1912 /* stop the trace while dumping */
1915 mutex_unlock(&trace_types_lock
);
1920 for_each_tracing_cpu(cpu
) {
1921 if (iter
->buffer_iter
[cpu
])
1922 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
1925 mutex_unlock(&trace_types_lock
);
1932 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
1934 if (tracing_disabled
)
1937 filp
->private_data
= inode
->i_private
;
1941 static int tracing_release(struct inode
*inode
, struct file
*file
)
1943 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
1944 struct trace_iterator
*iter
= m
->private;
1947 mutex_lock(&trace_types_lock
);
1948 for_each_tracing_cpu(cpu
) {
1949 if (iter
->buffer_iter
[cpu
])
1950 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
1953 if (iter
->trace
&& iter
->trace
->close
)
1954 iter
->trace
->close(iter
);
1956 /* reenable tracing if it was previously enabled */
1958 mutex_unlock(&trace_types_lock
);
1960 seq_release(inode
, file
);
1961 mutex_destroy(&iter
->mutex
);
1967 static int tracing_open(struct inode
*inode
, struct file
*file
)
1969 struct trace_iterator
*iter
;
1972 iter
= __tracing_open(inode
, file
);
1974 ret
= PTR_ERR(iter
);
1975 else if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
1976 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
1982 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1984 struct tracer
*t
= m
->private;
1996 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
1998 struct tracer
*t
= m
->private;
2001 mutex_lock(&trace_types_lock
);
2002 for (; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
2008 static void t_stop(struct seq_file
*m
, void *p
)
2010 mutex_unlock(&trace_types_lock
);
2013 static int t_show(struct seq_file
*m
, void *v
)
2015 struct tracer
*t
= v
;
2020 seq_printf(m
, "%s", t
->name
);
2029 static struct seq_operations show_traces_seq_ops
= {
2036 static int show_traces_open(struct inode
*inode
, struct file
*file
)
2040 if (tracing_disabled
)
2043 ret
= seq_open(file
, &show_traces_seq_ops
);
2045 struct seq_file
*m
= file
->private_data
;
2046 m
->private = trace_types
;
2052 static const struct file_operations tracing_fops
= {
2053 .open
= tracing_open
,
2055 .llseek
= seq_lseek
,
2056 .release
= tracing_release
,
2059 static const struct file_operations show_traces_fops
= {
2060 .open
= show_traces_open
,
2062 .release
= seq_release
,
2066 * Only trace on a CPU if the bitmask is set:
2068 static cpumask_var_t tracing_cpumask
;
2071 * The tracer itself will not take this lock, but still we want
2072 * to provide a consistent cpumask to user-space:
2074 static DEFINE_MUTEX(tracing_cpumask_update_lock
);
2077 * Temporary storage for the character representation of the
2078 * CPU bitmask (and one more byte for the newline):
2080 static char mask_str
[NR_CPUS
+ 1];
2083 tracing_cpumask_read(struct file
*filp
, char __user
*ubuf
,
2084 size_t count
, loff_t
*ppos
)
2088 mutex_lock(&tracing_cpumask_update_lock
);
2090 len
= cpumask_scnprintf(mask_str
, count
, tracing_cpumask
);
2091 if (count
- len
< 2) {
2095 len
+= sprintf(mask_str
+ len
, "\n");
2096 count
= simple_read_from_buffer(ubuf
, count
, ppos
, mask_str
, NR_CPUS
+1);
2099 mutex_unlock(&tracing_cpumask_update_lock
);
2105 tracing_cpumask_write(struct file
*filp
, const char __user
*ubuf
,
2106 size_t count
, loff_t
*ppos
)
2109 cpumask_var_t tracing_cpumask_new
;
2111 if (!alloc_cpumask_var(&tracing_cpumask_new
, GFP_KERNEL
))
2114 mutex_lock(&tracing_cpumask_update_lock
);
2115 err
= cpumask_parse_user(ubuf
, count
, tracing_cpumask_new
);
2119 local_irq_disable();
2120 __raw_spin_lock(&ftrace_max_lock
);
2121 for_each_tracing_cpu(cpu
) {
2123 * Increase/decrease the disabled counter if we are
2124 * about to flip a bit in the cpumask:
2126 if (cpumask_test_cpu(cpu
, tracing_cpumask
) &&
2127 !cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
2128 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
2130 if (!cpumask_test_cpu(cpu
, tracing_cpumask
) &&
2131 cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
2132 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
2135 __raw_spin_unlock(&ftrace_max_lock
);
2138 cpumask_copy(tracing_cpumask
, tracing_cpumask_new
);
2140 mutex_unlock(&tracing_cpumask_update_lock
);
2141 free_cpumask_var(tracing_cpumask_new
);
2146 mutex_unlock(&tracing_cpumask_update_lock
);
2147 free_cpumask_var(tracing_cpumask
);
2152 static const struct file_operations tracing_cpumask_fops
= {
2153 .open
= tracing_open_generic
,
2154 .read
= tracing_cpumask_read
,
2155 .write
= tracing_cpumask_write
,
2159 tracing_trace_options_read(struct file
*filp
, char __user
*ubuf
,
2160 size_t cnt
, loff_t
*ppos
)
2162 struct tracer_opt
*trace_opts
;
2170 /* calculate max size */
2171 for (i
= 0; trace_options
[i
]; i
++) {
2172 len
+= strlen(trace_options
[i
]);
2173 len
+= 3; /* "no" and newline */
2176 mutex_lock(&trace_types_lock
);
2177 tracer_flags
= current_trace
->flags
->val
;
2178 trace_opts
= current_trace
->flags
->opts
;
2181 * Increase the size with names of options specific
2182 * of the current tracer.
2184 for (i
= 0; trace_opts
[i
].name
; i
++) {
2185 len
+= strlen(trace_opts
[i
].name
);
2186 len
+= 3; /* "no" and newline */
2189 /* +2 for \n and \0 */
2190 buf
= kmalloc(len
+ 2, GFP_KERNEL
);
2192 mutex_unlock(&trace_types_lock
);
2196 for (i
= 0; trace_options
[i
]; i
++) {
2197 if (trace_flags
& (1 << i
))
2198 r
+= sprintf(buf
+ r
, "%s\n", trace_options
[i
]);
2200 r
+= sprintf(buf
+ r
, "no%s\n", trace_options
[i
]);
2203 for (i
= 0; trace_opts
[i
].name
; i
++) {
2204 if (tracer_flags
& trace_opts
[i
].bit
)
2205 r
+= sprintf(buf
+ r
, "%s\n",
2206 trace_opts
[i
].name
);
2208 r
+= sprintf(buf
+ r
, "no%s\n",
2209 trace_opts
[i
].name
);
2211 mutex_unlock(&trace_types_lock
);
2213 WARN_ON(r
>= len
+ 2);
2215 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2221 /* Try to assign a tracer specific option */
2222 static int set_tracer_option(struct tracer
*trace
, char *cmp
, int neg
)
2224 struct tracer_flags
*trace_flags
= trace
->flags
;
2225 struct tracer_opt
*opts
= NULL
;
2229 for (i
= 0; trace_flags
->opts
[i
].name
; i
++) {
2230 opts
= &trace_flags
->opts
[i
];
2231 len
= strlen(opts
->name
);
2233 if (strncmp(cmp
, opts
->name
, len
) == 0) {
2234 ret
= trace
->set_flag(trace_flags
->val
,
2240 if (!trace_flags
->opts
[i
].name
)
2243 /* Refused to handle */
2248 trace_flags
->val
&= ~opts
->bit
;
2250 trace_flags
->val
|= opts
->bit
;
2255 static void set_tracer_flags(unsigned int mask
, int enabled
)
2257 /* do nothing if flag is already set */
2258 if (!!(trace_flags
& mask
) == !!enabled
)
2262 trace_flags
|= mask
;
2264 trace_flags
&= ~mask
;
2266 if (mask
== TRACE_ITER_GLOBAL_CLK
) {
2270 func
= trace_clock_global
;
2272 func
= trace_clock_local
;
2274 mutex_lock(&trace_types_lock
);
2275 ring_buffer_set_clock(global_trace
.buffer
, func
);
2278 ring_buffer_set_clock(max_tr
.buffer
, func
);
2279 mutex_unlock(&trace_types_lock
);
2284 tracing_trace_options_write(struct file
*filp
, const char __user
*ubuf
,
2285 size_t cnt
, loff_t
*ppos
)
2293 if (cnt
>= sizeof(buf
))
2296 if (copy_from_user(&buf
, ubuf
, cnt
))
2301 if (strncmp(buf
, "no", 2) == 0) {
2306 for (i
= 0; trace_options
[i
]; i
++) {
2307 int len
= strlen(trace_options
[i
]);
2309 if (strncmp(cmp
, trace_options
[i
], len
) == 0) {
2310 set_tracer_flags(1 << i
, !neg
);
2315 /* If no option could be set, test the specific tracer options */
2316 if (!trace_options
[i
]) {
2317 mutex_lock(&trace_types_lock
);
2318 ret
= set_tracer_option(current_trace
, cmp
, neg
);
2319 mutex_unlock(&trace_types_lock
);
2329 static const struct file_operations tracing_iter_fops
= {
2330 .open
= tracing_open_generic
,
2331 .read
= tracing_trace_options_read
,
2332 .write
= tracing_trace_options_write
,
2335 static const char readme_msg
[] =
2336 "tracing mini-HOWTO:\n\n"
2338 "# mount -t debugfs nodev /debug\n\n"
2339 "# cat /debug/tracing/available_tracers\n"
2340 "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
2341 "# cat /debug/tracing/current_tracer\n"
2343 "# echo sched_switch > /debug/tracing/current_tracer\n"
2344 "# cat /debug/tracing/current_tracer\n"
2346 "# cat /debug/tracing/trace_options\n"
2347 "noprint-parent nosym-offset nosym-addr noverbose\n"
2348 "# echo print-parent > /debug/tracing/trace_options\n"
2349 "# echo 1 > /debug/tracing/tracing_enabled\n"
2350 "# cat /debug/tracing/trace > /tmp/trace.txt\n"
2351 "echo 0 > /debug/tracing/tracing_enabled\n"
2355 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
2356 size_t cnt
, loff_t
*ppos
)
2358 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
2359 readme_msg
, strlen(readme_msg
));
2362 static const struct file_operations tracing_readme_fops
= {
2363 .open
= tracing_open_generic
,
2364 .read
= tracing_readme_read
,
2368 tracing_ctrl_read(struct file
*filp
, char __user
*ubuf
,
2369 size_t cnt
, loff_t
*ppos
)
2374 r
= sprintf(buf
, "%u\n", tracer_enabled
);
2375 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2379 tracing_ctrl_write(struct file
*filp
, const char __user
*ubuf
,
2380 size_t cnt
, loff_t
*ppos
)
2382 struct trace_array
*tr
= filp
->private_data
;
2387 if (cnt
>= sizeof(buf
))
2390 if (copy_from_user(&buf
, ubuf
, cnt
))
2395 ret
= strict_strtoul(buf
, 10, &val
);
2401 mutex_lock(&trace_types_lock
);
2402 if (tracer_enabled
^ val
) {
2405 if (current_trace
->start
)
2406 current_trace
->start(tr
);
2411 if (current_trace
->stop
)
2412 current_trace
->stop(tr
);
2415 mutex_unlock(&trace_types_lock
);
2423 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
2424 size_t cnt
, loff_t
*ppos
)
2426 char buf
[max_tracer_type_len
+2];
2429 mutex_lock(&trace_types_lock
);
2431 r
= sprintf(buf
, "%s\n", current_trace
->name
);
2433 r
= sprintf(buf
, "\n");
2434 mutex_unlock(&trace_types_lock
);
2436 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2439 int tracer_init(struct tracer
*t
, struct trace_array
*tr
)
2441 tracing_reset_online_cpus(tr
);
2445 static int tracing_resize_ring_buffer(unsigned long size
)
2450 * If kernel or user changes the size of the ring buffer
2451 * we use the size that was given, and we can forget about
2452 * expanding it later.
2454 ring_buffer_expanded
= 1;
2456 ret
= ring_buffer_resize(global_trace
.buffer
, size
);
2460 ret
= ring_buffer_resize(max_tr
.buffer
, size
);
2464 r
= ring_buffer_resize(global_trace
.buffer
,
2465 global_trace
.entries
);
2468 * AARGH! We are left with different
2469 * size max buffer!!!!
2470 * The max buffer is our "snapshot" buffer.
2471 * When a tracer needs a snapshot (one of the
2472 * latency tracers), it swaps the max buffer
2473 * with the saved snap shot. We succeeded to
2474 * update the size of the main buffer, but failed to
2475 * update the size of the max buffer. But when we tried
2476 * to reset the main buffer to the original size, we
2477 * failed there too. This is very unlikely to
2478 * happen, but if it does, warn and kill all
2482 tracing_disabled
= 1;
2487 global_trace
.entries
= size
;
2493 * tracing_update_buffers - used by tracing facility to expand ring buffers
2495 * To save on memory when the tracing is never used on a system with it
2496 * configured in. The ring buffers are set to a minimum size. But once
2497 * a user starts to use the tracing facility, then they need to grow
2498 * to their default size.
2500 * This function is to be called when a tracer is about to be used.
2502 int tracing_update_buffers(void)
2506 mutex_lock(&trace_types_lock
);
2507 if (!ring_buffer_expanded
)
2508 ret
= tracing_resize_ring_buffer(trace_buf_size
);
2509 mutex_unlock(&trace_types_lock
);
2514 struct trace_option_dentry
;
2516 static struct trace_option_dentry
*
2517 create_trace_option_files(struct tracer
*tracer
);
2520 destroy_trace_option_files(struct trace_option_dentry
*topts
);
2522 static int tracing_set_tracer(const char *buf
)
2524 static struct trace_option_dentry
*topts
;
2525 struct trace_array
*tr
= &global_trace
;
2529 mutex_lock(&trace_types_lock
);
2531 if (!ring_buffer_expanded
) {
2532 ret
= tracing_resize_ring_buffer(trace_buf_size
);
2538 for (t
= trace_types
; t
; t
= t
->next
) {
2539 if (strcmp(t
->name
, buf
) == 0)
2546 if (t
== current_trace
)
2549 trace_branch_disable();
2550 if (current_trace
&& current_trace
->reset
)
2551 current_trace
->reset(tr
);
2553 destroy_trace_option_files(topts
);
2557 topts
= create_trace_option_files(current_trace
);
2560 ret
= tracer_init(t
, tr
);
2565 trace_branch_enable(tr
);
2567 mutex_unlock(&trace_types_lock
);
2573 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
2574 size_t cnt
, loff_t
*ppos
)
2576 char buf
[max_tracer_type_len
+1];
2583 if (cnt
> max_tracer_type_len
)
2584 cnt
= max_tracer_type_len
;
2586 if (copy_from_user(&buf
, ubuf
, cnt
))
2591 /* strip ending whitespace. */
2592 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
2595 err
= tracing_set_tracer(buf
);
2605 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
2606 size_t cnt
, loff_t
*ppos
)
2608 unsigned long *ptr
= filp
->private_data
;
2612 r
= snprintf(buf
, sizeof(buf
), "%ld\n",
2613 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
2614 if (r
> sizeof(buf
))
2616 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2620 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
2621 size_t cnt
, loff_t
*ppos
)
2623 unsigned long *ptr
= filp
->private_data
;
2628 if (cnt
>= sizeof(buf
))
2631 if (copy_from_user(&buf
, ubuf
, cnt
))
2636 ret
= strict_strtoul(buf
, 10, &val
);
2645 static int tracing_open_pipe(struct inode
*inode
, struct file
*filp
)
2647 long cpu_file
= (long) inode
->i_private
;
2648 struct trace_iterator
*iter
;
2651 if (tracing_disabled
)
2654 mutex_lock(&trace_types_lock
);
2656 /* We only allow one reader per cpu */
2657 if (cpu_file
== TRACE_PIPE_ALL_CPU
) {
2658 if (!cpumask_empty(tracing_reader_cpumask
)) {
2662 cpumask_setall(tracing_reader_cpumask
);
2664 if (!cpumask_test_cpu(cpu_file
, tracing_reader_cpumask
))
2665 cpumask_set_cpu(cpu_file
, tracing_reader_cpumask
);
2672 /* create a buffer to store the information to pass to userspace */
2673 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2680 * We make a copy of the current tracer to avoid concurrent
2681 * changes on it while we are reading.
2683 iter
->trace
= kmalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
2689 *iter
->trace
= *current_trace
;
2691 if (!alloc_cpumask_var(&iter
->started
, GFP_KERNEL
)) {
2696 /* trace pipe does not show start of buffer */
2697 cpumask_setall(iter
->started
);
2699 iter
->cpu_file
= cpu_file
;
2700 iter
->tr
= &global_trace
;
2701 mutex_init(&iter
->mutex
);
2702 filp
->private_data
= iter
;
2704 if (iter
->trace
->pipe_open
)
2705 iter
->trace
->pipe_open(iter
);
2708 mutex_unlock(&trace_types_lock
);
2714 mutex_unlock(&trace_types_lock
);
2718 static int tracing_release_pipe(struct inode
*inode
, struct file
*file
)
2720 struct trace_iterator
*iter
= file
->private_data
;
2722 mutex_lock(&trace_types_lock
);
2724 if (iter
->cpu_file
== TRACE_PIPE_ALL_CPU
)
2725 cpumask_clear(tracing_reader_cpumask
);
2727 cpumask_clear_cpu(iter
->cpu_file
, tracing_reader_cpumask
);
2729 mutex_unlock(&trace_types_lock
);
2731 free_cpumask_var(iter
->started
);
2732 mutex_destroy(&iter
->mutex
);
2740 tracing_poll_pipe(struct file
*filp
, poll_table
*poll_table
)
2742 struct trace_iterator
*iter
= filp
->private_data
;
2744 if (trace_flags
& TRACE_ITER_BLOCK
) {
2746 * Always select as readable when in blocking mode
2748 return POLLIN
| POLLRDNORM
;
2750 if (!trace_empty(iter
))
2751 return POLLIN
| POLLRDNORM
;
2752 poll_wait(filp
, &trace_wait
, poll_table
);
2753 if (!trace_empty(iter
))
2754 return POLLIN
| POLLRDNORM
;
2761 void default_wait_pipe(struct trace_iterator
*iter
)
2765 prepare_to_wait(&trace_wait
, &wait
, TASK_INTERRUPTIBLE
);
2767 if (trace_empty(iter
))
2770 finish_wait(&trace_wait
, &wait
);
2774 * This is a make-shift waitqueue.
2775 * A tracer might use this callback on some rare cases:
2777 * 1) the current tracer might hold the runqueue lock when it wakes up
2778 * a reader, hence a deadlock (sched, function, and function graph tracers)
2779 * 2) the function tracers, trace all functions, we don't want
2780 * the overhead of calling wake_up and friends
2781 * (and tracing them too)
2783 * Anyway, this is really very primitive wakeup.
2785 void poll_wait_pipe(struct trace_iterator
*iter
)
2787 set_current_state(TASK_INTERRUPTIBLE
);
2788 /* sleep for 100 msecs, and try again. */
2789 schedule_timeout(HZ
/ 10);
2792 /* Must be called with trace_types_lock mutex held. */
2793 static int tracing_wait_pipe(struct file
*filp
)
2795 struct trace_iterator
*iter
= filp
->private_data
;
2797 while (trace_empty(iter
)) {
2799 if ((filp
->f_flags
& O_NONBLOCK
)) {
2803 mutex_unlock(&iter
->mutex
);
2805 iter
->trace
->wait_pipe(iter
);
2807 mutex_lock(&iter
->mutex
);
2809 if (signal_pending(current
))
2813 * We block until we read something and tracing is disabled.
2814 * We still block if tracing is disabled, but we have never
2815 * read anything. This allows a user to cat this file, and
2816 * then enable tracing. But after we have read something,
2817 * we give an EOF when tracing is again disabled.
2819 * iter->pos will be 0 if we haven't read anything.
2821 if (!tracer_enabled
&& iter
->pos
)
2832 tracing_read_pipe(struct file
*filp
, char __user
*ubuf
,
2833 size_t cnt
, loff_t
*ppos
)
2835 struct trace_iterator
*iter
= filp
->private_data
;
2836 static struct tracer
*old_tracer
;
2839 /* return any leftover data */
2840 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
2844 trace_seq_init(&iter
->seq
);
2846 /* copy the tracer to avoid using a global lock all around */
2847 mutex_lock(&trace_types_lock
);
2848 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
2849 old_tracer
= current_trace
;
2850 *iter
->trace
= *current_trace
;
2852 mutex_unlock(&trace_types_lock
);
2855 * Avoid more than one consumer on a single file descriptor
2856 * This is just a matter of traces coherency, the ring buffer itself
2859 mutex_lock(&iter
->mutex
);
2860 if (iter
->trace
->read
) {
2861 sret
= iter
->trace
->read(iter
, filp
, ubuf
, cnt
, ppos
);
2867 sret
= tracing_wait_pipe(filp
);
2871 /* stop when tracing is finished */
2872 if (trace_empty(iter
)) {
2877 if (cnt
>= PAGE_SIZE
)
2878 cnt
= PAGE_SIZE
- 1;
2880 /* reset all but tr, trace, and overruns */
2881 memset(&iter
->seq
, 0,
2882 sizeof(struct trace_iterator
) -
2883 offsetof(struct trace_iterator
, seq
));
2886 while (find_next_entry_inc(iter
) != NULL
) {
2887 enum print_line_t ret
;
2888 int len
= iter
->seq
.len
;
2890 ret
= print_trace_line(iter
);
2891 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
2892 /* don't print partial lines */
2893 iter
->seq
.len
= len
;
2896 if (ret
!= TRACE_TYPE_NO_CONSUME
)
2897 trace_consume(iter
);
2899 if (iter
->seq
.len
>= cnt
)
2903 /* Now copy what we have to the user */
2904 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
2905 if (iter
->seq
.readpos
>= iter
->seq
.len
)
2906 trace_seq_init(&iter
->seq
);
2909 * If there was nothing to send to user, inspite of consuming trace
2910 * entries, go back to wait for more entries.
2916 mutex_unlock(&iter
->mutex
);
2921 static void tracing_pipe_buf_release(struct pipe_inode_info
*pipe
,
2922 struct pipe_buffer
*buf
)
2924 __free_page(buf
->page
);
2927 static void tracing_spd_release_pipe(struct splice_pipe_desc
*spd
,
2930 __free_page(spd
->pages
[idx
]);
2933 static struct pipe_buf_operations tracing_pipe_buf_ops
= {
2935 .map
= generic_pipe_buf_map
,
2936 .unmap
= generic_pipe_buf_unmap
,
2937 .confirm
= generic_pipe_buf_confirm
,
2938 .release
= tracing_pipe_buf_release
,
2939 .steal
= generic_pipe_buf_steal
,
2940 .get
= generic_pipe_buf_get
,
2944 tracing_fill_pipe_page(size_t rem
, struct trace_iterator
*iter
)
2949 /* Seq buffer is page-sized, exactly what we need. */
2951 count
= iter
->seq
.len
;
2952 ret
= print_trace_line(iter
);
2953 count
= iter
->seq
.len
- count
;
2956 iter
->seq
.len
-= count
;
2959 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
2960 iter
->seq
.len
-= count
;
2964 trace_consume(iter
);
2966 if (!find_next_entry_inc(iter
)) {
2976 static ssize_t
tracing_splice_read_pipe(struct file
*filp
,
2978 struct pipe_inode_info
*pipe
,
2982 struct page
*pages
[PIPE_BUFFERS
];
2983 struct partial_page partial
[PIPE_BUFFERS
];
2984 struct trace_iterator
*iter
= filp
->private_data
;
2985 struct splice_pipe_desc spd
= {
2988 .nr_pages
= 0, /* This gets updated below. */
2990 .ops
= &tracing_pipe_buf_ops
,
2991 .spd_release
= tracing_spd_release_pipe
,
2993 static struct tracer
*old_tracer
;
2998 /* copy the tracer to avoid using a global lock all around */
2999 mutex_lock(&trace_types_lock
);
3000 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
3001 old_tracer
= current_trace
;
3002 *iter
->trace
= *current_trace
;
3004 mutex_unlock(&trace_types_lock
);
3006 mutex_lock(&iter
->mutex
);
3008 if (iter
->trace
->splice_read
) {
3009 ret
= iter
->trace
->splice_read(iter
, filp
,
3010 ppos
, pipe
, len
, flags
);
3015 ret
= tracing_wait_pipe(filp
);
3019 if (!iter
->ent
&& !find_next_entry_inc(iter
)) {
3024 /* Fill as many pages as possible. */
3025 for (i
= 0, rem
= len
; i
< PIPE_BUFFERS
&& rem
; i
++) {
3026 pages
[i
] = alloc_page(GFP_KERNEL
);
3030 rem
= tracing_fill_pipe_page(rem
, iter
);
3032 /* Copy the data into the page, so we can start over. */
3033 ret
= trace_seq_to_buffer(&iter
->seq
,
3034 page_address(pages
[i
]),
3037 __free_page(pages
[i
]);
3040 partial
[i
].offset
= 0;
3041 partial
[i
].len
= iter
->seq
.len
;
3043 trace_seq_init(&iter
->seq
);
3046 mutex_unlock(&iter
->mutex
);
3050 return splice_to_pipe(pipe
, &spd
);
3053 mutex_unlock(&iter
->mutex
);
3059 tracing_entries_read(struct file
*filp
, char __user
*ubuf
,
3060 size_t cnt
, loff_t
*ppos
)
3062 struct trace_array
*tr
= filp
->private_data
;
3066 mutex_lock(&trace_types_lock
);
3067 if (!ring_buffer_expanded
)
3068 r
= sprintf(buf
, "%lu (expanded: %lu)\n",
3070 trace_buf_size
>> 10);
3072 r
= sprintf(buf
, "%lu\n", tr
->entries
>> 10);
3073 mutex_unlock(&trace_types_lock
);
3075 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3079 tracing_entries_write(struct file
*filp
, const char __user
*ubuf
,
3080 size_t cnt
, loff_t
*ppos
)
3086 if (cnt
>= sizeof(buf
))
3089 if (copy_from_user(&buf
, ubuf
, cnt
))
3094 ret
= strict_strtoul(buf
, 10, &val
);
3098 /* must have at least 1 entry */
3102 mutex_lock(&trace_types_lock
);
3106 /* disable all cpu buffers */
3107 for_each_tracing_cpu(cpu
) {
3108 if (global_trace
.data
[cpu
])
3109 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
3110 if (max_tr
.data
[cpu
])
3111 atomic_inc(&max_tr
.data
[cpu
]->disabled
);
3114 /* value is in KB */
3117 if (val
!= global_trace
.entries
) {
3118 ret
= tracing_resize_ring_buffer(val
);
3127 /* If check pages failed, return ENOMEM */
3128 if (tracing_disabled
)
3131 for_each_tracing_cpu(cpu
) {
3132 if (global_trace
.data
[cpu
])
3133 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
3134 if (max_tr
.data
[cpu
])
3135 atomic_dec(&max_tr
.data
[cpu
]->disabled
);
3139 max_tr
.entries
= global_trace
.entries
;
3140 mutex_unlock(&trace_types_lock
);
3145 static int mark_printk(const char *fmt
, ...)
3149 va_start(args
, fmt
);
3150 ret
= trace_vprintk(0, -1, fmt
, args
);
3156 tracing_mark_write(struct file
*filp
, const char __user
*ubuf
,
3157 size_t cnt
, loff_t
*fpos
)
3162 if (tracing_disabled
)
3165 if (cnt
> TRACE_BUF_SIZE
)
3166 cnt
= TRACE_BUF_SIZE
;
3168 buf
= kmalloc(cnt
+ 1, GFP_KERNEL
);
3172 if (copy_from_user(buf
, ubuf
, cnt
)) {
3177 /* Cut from the first nil or newline. */
3179 end
= strchr(buf
, '\n');
3183 cnt
= mark_printk("%s\n", buf
);
3190 static const struct file_operations tracing_max_lat_fops
= {
3191 .open
= tracing_open_generic
,
3192 .read
= tracing_max_lat_read
,
3193 .write
= tracing_max_lat_write
,
3196 static const struct file_operations tracing_ctrl_fops
= {
3197 .open
= tracing_open_generic
,
3198 .read
= tracing_ctrl_read
,
3199 .write
= tracing_ctrl_write
,
3202 static const struct file_operations set_tracer_fops
= {
3203 .open
= tracing_open_generic
,
3204 .read
= tracing_set_trace_read
,
3205 .write
= tracing_set_trace_write
,
3208 static const struct file_operations tracing_pipe_fops
= {
3209 .open
= tracing_open_pipe
,
3210 .poll
= tracing_poll_pipe
,
3211 .read
= tracing_read_pipe
,
3212 .splice_read
= tracing_splice_read_pipe
,
3213 .release
= tracing_release_pipe
,
3216 static const struct file_operations tracing_entries_fops
= {
3217 .open
= tracing_open_generic
,
3218 .read
= tracing_entries_read
,
3219 .write
= tracing_entries_write
,
3222 static const struct file_operations tracing_mark_fops
= {
3223 .open
= tracing_open_generic
,
3224 .write
= tracing_mark_write
,
3227 struct ftrace_buffer_info
{
3228 struct trace_array
*tr
;
3234 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
)
3236 int cpu
= (int)(long)inode
->i_private
;
3237 struct ftrace_buffer_info
*info
;
3239 if (tracing_disabled
)
3242 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
3246 info
->tr
= &global_trace
;
3248 info
->spare
= ring_buffer_alloc_read_page(info
->tr
->buffer
);
3249 /* Force reading ring buffer for first read */
3250 info
->read
= (unsigned int)-1;
3254 filp
->private_data
= info
;
3264 tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
3265 size_t count
, loff_t
*ppos
)
3267 struct ftrace_buffer_info
*info
= filp
->private_data
;
3275 /* Do we have previous read data to read? */
3276 if (info
->read
< PAGE_SIZE
)
3281 ret
= ring_buffer_read_page(info
->tr
->buffer
,
3288 pos
= ring_buffer_page_len(info
->spare
);
3290 if (pos
< PAGE_SIZE
)
3291 memset(info
->spare
+ pos
, 0, PAGE_SIZE
- pos
);
3294 size
= PAGE_SIZE
- info
->read
;
3298 ret
= copy_to_user(ubuf
, info
->spare
+ info
->read
, size
);
3309 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
)
3311 struct ftrace_buffer_info
*info
= file
->private_data
;
3313 ring_buffer_free_read_page(info
->tr
->buffer
, info
->spare
);
3320 struct ring_buffer
*buffer
;
3325 static void buffer_pipe_buf_release(struct pipe_inode_info
*pipe
,
3326 struct pipe_buffer
*buf
)
3328 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
3333 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
3338 static int buffer_pipe_buf_steal(struct pipe_inode_info
*pipe
,
3339 struct pipe_buffer
*buf
)
3344 static void buffer_pipe_buf_get(struct pipe_inode_info
*pipe
,
3345 struct pipe_buffer
*buf
)
3347 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
3352 /* Pipe buffer operations for a buffer. */
3353 static struct pipe_buf_operations buffer_pipe_buf_ops
= {
3355 .map
= generic_pipe_buf_map
,
3356 .unmap
= generic_pipe_buf_unmap
,
3357 .confirm
= generic_pipe_buf_confirm
,
3358 .release
= buffer_pipe_buf_release
,
3359 .steal
= buffer_pipe_buf_steal
,
3360 .get
= buffer_pipe_buf_get
,
3364 * Callback from splice_to_pipe(), if we need to release some pages
3365 * at the end of the spd in case we error'ed out in filling the pipe.
3367 static void buffer_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
3369 struct buffer_ref
*ref
=
3370 (struct buffer_ref
*)spd
->partial
[i
].private;
3375 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
3377 spd
->partial
[i
].private = 0;
3381 tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
3382 struct pipe_inode_info
*pipe
, size_t len
,
3385 struct ftrace_buffer_info
*info
= file
->private_data
;
3386 struct partial_page partial
[PIPE_BUFFERS
];
3387 struct page
*pages
[PIPE_BUFFERS
];
3388 struct splice_pipe_desc spd
= {
3392 .ops
= &buffer_pipe_buf_ops
,
3393 .spd_release
= buffer_spd_release
,
3395 struct buffer_ref
*ref
;
3400 * We can't seek on a buffer input
3402 if (unlikely(*ppos
))
3406 for (i
= 0; i
< PIPE_BUFFERS
&& len
; i
++, len
-= size
) {
3410 ref
= kzalloc(sizeof(*ref
), GFP_KERNEL
);
3414 ref
->buffer
= info
->tr
->buffer
;
3415 ref
->page
= ring_buffer_alloc_read_page(ref
->buffer
);
3421 r
= ring_buffer_read_page(ref
->buffer
, &ref
->page
,
3424 ring_buffer_free_read_page(ref
->buffer
,
3431 * zero out any left over data, this is going to
3434 size
= ring_buffer_page_len(ref
->page
);
3435 if (size
< PAGE_SIZE
)
3436 memset(ref
->page
+ size
, 0, PAGE_SIZE
- size
);
3438 page
= virt_to_page(ref
->page
);
3440 spd
.pages
[i
] = page
;
3441 spd
.partial
[i
].len
= PAGE_SIZE
;
3442 spd
.partial
[i
].offset
= 0;
3443 spd
.partial
[i
].private = (unsigned long)ref
;
3449 /* did we read anything? */
3450 if (!spd
.nr_pages
) {
3451 if (flags
& SPLICE_F_NONBLOCK
)
3459 ret
= splice_to_pipe(pipe
, &spd
);
3464 static const struct file_operations tracing_buffers_fops
= {
3465 .open
= tracing_buffers_open
,
3466 .read
= tracing_buffers_read
,
3467 .release
= tracing_buffers_release
,
3468 .splice_read
= tracing_buffers_splice_read
,
3469 .llseek
= no_llseek
,
3472 #ifdef CONFIG_DYNAMIC_FTRACE
3474 int __weak
ftrace_arch_read_dyn_info(char *buf
, int size
)
3480 tracing_read_dyn_info(struct file
*filp
, char __user
*ubuf
,
3481 size_t cnt
, loff_t
*ppos
)
3483 static char ftrace_dyn_info_buffer
[1024];
3484 static DEFINE_MUTEX(dyn_info_mutex
);
3485 unsigned long *p
= filp
->private_data
;
3486 char *buf
= ftrace_dyn_info_buffer
;
3487 int size
= ARRAY_SIZE(ftrace_dyn_info_buffer
);
3490 mutex_lock(&dyn_info_mutex
);
3491 r
= sprintf(buf
, "%ld ", *p
);
3493 r
+= ftrace_arch_read_dyn_info(buf
+r
, (size
-1)-r
);
3496 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3498 mutex_unlock(&dyn_info_mutex
);
3503 static const struct file_operations tracing_dyn_info_fops
= {
3504 .open
= tracing_open_generic
,
3505 .read
= tracing_read_dyn_info
,
3509 static struct dentry
*d_tracer
;
3511 struct dentry
*tracing_init_dentry(void)
3518 d_tracer
= debugfs_create_dir("tracing", NULL
);
3520 if (!d_tracer
&& !once
) {
3522 pr_warning("Could not create debugfs directory 'tracing'\n");
3529 static struct dentry
*d_percpu
;
3531 struct dentry
*tracing_dentry_percpu(void)
3534 struct dentry
*d_tracer
;
3539 d_tracer
= tracing_init_dentry();
3544 d_percpu
= debugfs_create_dir("per_cpu", d_tracer
);
3546 if (!d_percpu
&& !once
) {
3548 pr_warning("Could not create debugfs directory 'per_cpu'\n");
3555 static void tracing_init_debugfs_percpu(long cpu
)
3557 struct dentry
*d_percpu
= tracing_dentry_percpu();
3558 struct dentry
*entry
, *d_cpu
;
3559 /* strlen(cpu) + MAX(log10(cpu)) + '\0' */
3562 if (cpu
> 999 || cpu
< 0)
3565 sprintf(cpu_dir
, "cpu%ld", cpu
);
3566 d_cpu
= debugfs_create_dir(cpu_dir
, d_percpu
);
3568 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir
);
3572 /* per cpu trace_pipe */
3573 entry
= debugfs_create_file("trace_pipe", 0444, d_cpu
,
3574 (void *) cpu
, &tracing_pipe_fops
);
3576 pr_warning("Could not create debugfs 'trace_pipe' entry\n");
3579 entry
= debugfs_create_file("trace", 0444, d_cpu
,
3580 (void *) cpu
, &tracing_fops
);
3582 pr_warning("Could not create debugfs 'trace' entry\n");
3584 entry
= debugfs_create_file("trace_pipe_raw", 0444, d_cpu
,
3585 (void *) cpu
, &tracing_buffers_fops
);
3587 pr_warning("Could not create debugfs 'trace_pipe_raw' entry\n");
3590 #ifdef CONFIG_FTRACE_SELFTEST
3591 /* Let selftest have access to static functions in this file */
3592 #include "trace_selftest.c"
3595 struct trace_option_dentry
{
3596 struct tracer_opt
*opt
;
3597 struct tracer_flags
*flags
;
3598 struct dentry
*entry
;
3602 trace_options_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
3605 struct trace_option_dentry
*topt
= filp
->private_data
;
3608 if (topt
->flags
->val
& topt
->opt
->bit
)
3613 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
3617 trace_options_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
3620 struct trace_option_dentry
*topt
= filp
->private_data
;
3625 if (cnt
>= sizeof(buf
))
3628 if (copy_from_user(&buf
, ubuf
, cnt
))
3633 ret
= strict_strtoul(buf
, 10, &val
);
3640 /* do nothing if already cleared */
3641 if (!(topt
->flags
->val
& topt
->opt
->bit
))
3644 mutex_lock(&trace_types_lock
);
3645 if (current_trace
->set_flag
)
3646 ret
= current_trace
->set_flag(topt
->flags
->val
,
3648 mutex_unlock(&trace_types_lock
);
3651 topt
->flags
->val
&= ~topt
->opt
->bit
;
3654 /* do nothing if already set */
3655 if (topt
->flags
->val
& topt
->opt
->bit
)
3658 mutex_lock(&trace_types_lock
);
3659 if (current_trace
->set_flag
)
3660 ret
= current_trace
->set_flag(topt
->flags
->val
,
3662 mutex_unlock(&trace_types_lock
);
3665 topt
->flags
->val
|= topt
->opt
->bit
;
3678 static const struct file_operations trace_options_fops
= {
3679 .open
= tracing_open_generic
,
3680 .read
= trace_options_read
,
3681 .write
= trace_options_write
,
3685 trace_options_core_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
3688 long index
= (long)filp
->private_data
;
3691 if (trace_flags
& (1 << index
))
3696 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
3700 trace_options_core_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
3703 long index
= (long)filp
->private_data
;
3708 if (cnt
>= sizeof(buf
))
3711 if (copy_from_user(&buf
, ubuf
, cnt
))
3716 ret
= strict_strtoul(buf
, 10, &val
);
3722 trace_flags
&= ~(1 << index
);
3725 trace_flags
|= 1 << index
;
3737 static const struct file_operations trace_options_core_fops
= {
3738 .open
= tracing_open_generic
,
3739 .read
= trace_options_core_read
,
3740 .write
= trace_options_core_write
,
3743 static struct dentry
*trace_options_init_dentry(void)
3745 struct dentry
*d_tracer
;
3746 static struct dentry
*t_options
;
3751 d_tracer
= tracing_init_dentry();
3755 t_options
= debugfs_create_dir("options", d_tracer
);
3757 pr_warning("Could not create debugfs directory 'options'\n");
3765 create_trace_option_file(struct trace_option_dentry
*topt
,
3766 struct tracer_flags
*flags
,
3767 struct tracer_opt
*opt
)
3769 struct dentry
*t_options
;
3770 struct dentry
*entry
;
3772 t_options
= trace_options_init_dentry();
3776 topt
->flags
= flags
;
3779 entry
= debugfs_create_file(opt
->name
, 0644, t_options
, topt
,
3780 &trace_options_fops
);
3782 topt
->entry
= entry
;
3786 static struct trace_option_dentry
*
3787 create_trace_option_files(struct tracer
*tracer
)
3789 struct trace_option_dentry
*topts
;
3790 struct tracer_flags
*flags
;
3791 struct tracer_opt
*opts
;
3797 flags
= tracer
->flags
;
3799 if (!flags
|| !flags
->opts
)
3804 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
3807 topts
= kcalloc(cnt
+ 1, sizeof(*topts
), GFP_KERNEL
);
3811 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
3812 create_trace_option_file(&topts
[cnt
], flags
,
3819 destroy_trace_option_files(struct trace_option_dentry
*topts
)
3826 for (cnt
= 0; topts
[cnt
].opt
; cnt
++) {
3827 if (topts
[cnt
].entry
)
3828 debugfs_remove(topts
[cnt
].entry
);
3834 static struct dentry
*
3835 create_trace_option_core_file(const char *option
, long index
)
3837 struct dentry
*t_options
;
3838 struct dentry
*entry
;
3840 t_options
= trace_options_init_dentry();
3844 entry
= debugfs_create_file(option
, 0644, t_options
, (void *)index
,
3845 &trace_options_core_fops
);
3850 static __init
void create_trace_options_dir(void)
3852 struct dentry
*t_options
;
3853 struct dentry
*entry
;
3856 t_options
= trace_options_init_dentry();
3860 for (i
= 0; trace_options
[i
]; i
++) {
3861 entry
= create_trace_option_core_file(trace_options
[i
], i
);
3863 pr_warning("Could not create debugfs %s entry\n",
3868 static __init
int tracer_init_debugfs(void)
3870 struct dentry
*d_tracer
;
3871 struct dentry
*entry
;
3874 d_tracer
= tracing_init_dentry();
3876 entry
= debugfs_create_file("tracing_enabled", 0644, d_tracer
,
3877 &global_trace
, &tracing_ctrl_fops
);
3879 pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
3881 entry
= debugfs_create_file("trace_options", 0644, d_tracer
,
3882 NULL
, &tracing_iter_fops
);
3884 pr_warning("Could not create debugfs 'trace_options' entry\n");
3886 create_trace_options_dir();
3888 entry
= debugfs_create_file("tracing_cpumask", 0644, d_tracer
,
3889 NULL
, &tracing_cpumask_fops
);
3891 pr_warning("Could not create debugfs 'tracing_cpumask' entry\n");
3893 entry
= debugfs_create_file("trace", 0444, d_tracer
,
3894 (void *) TRACE_PIPE_ALL_CPU
, &tracing_fops
);
3896 pr_warning("Could not create debugfs 'trace' entry\n");
3898 entry
= debugfs_create_file("available_tracers", 0444, d_tracer
,
3899 &global_trace
, &show_traces_fops
);
3901 pr_warning("Could not create debugfs 'available_tracers' entry\n");
3903 entry
= debugfs_create_file("current_tracer", 0444, d_tracer
,
3904 &global_trace
, &set_tracer_fops
);
3906 pr_warning("Could not create debugfs 'current_tracer' entry\n");
3908 entry
= debugfs_create_file("tracing_max_latency", 0644, d_tracer
,
3909 &tracing_max_latency
,
3910 &tracing_max_lat_fops
);
3912 pr_warning("Could not create debugfs "
3913 "'tracing_max_latency' entry\n");
3915 entry
= debugfs_create_file("tracing_thresh", 0644, d_tracer
,
3916 &tracing_thresh
, &tracing_max_lat_fops
);
3918 pr_warning("Could not create debugfs "
3919 "'tracing_thresh' entry\n");
3920 entry
= debugfs_create_file("README", 0644, d_tracer
,
3921 NULL
, &tracing_readme_fops
);
3923 pr_warning("Could not create debugfs 'README' entry\n");
3925 entry
= debugfs_create_file("trace_pipe", 0444, d_tracer
,
3926 (void *) TRACE_PIPE_ALL_CPU
, &tracing_pipe_fops
);
3928 pr_warning("Could not create debugfs "
3929 "'trace_pipe' entry\n");
3931 entry
= debugfs_create_file("buffer_size_kb", 0644, d_tracer
,
3932 &global_trace
, &tracing_entries_fops
);
3934 pr_warning("Could not create debugfs "
3935 "'buffer_size_kb' entry\n");
3937 entry
= debugfs_create_file("trace_marker", 0220, d_tracer
,
3938 NULL
, &tracing_mark_fops
);
3940 pr_warning("Could not create debugfs "
3941 "'trace_marker' entry\n");
3943 #ifdef CONFIG_DYNAMIC_FTRACE
3944 entry
= debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
3945 &ftrace_update_tot_cnt
,
3946 &tracing_dyn_info_fops
);
3948 pr_warning("Could not create debugfs "
3949 "'dyn_ftrace_total_info' entry\n");
3951 #ifdef CONFIG_SYSPROF_TRACER
3952 init_tracer_sysprof_debugfs(d_tracer
);
3955 for_each_tracing_cpu(cpu
)
3956 tracing_init_debugfs_percpu(cpu
);
3961 static int trace_panic_handler(struct notifier_block
*this,
3962 unsigned long event
, void *unused
)
3964 if (ftrace_dump_on_oops
)
3969 static struct notifier_block trace_panic_notifier
= {
3970 .notifier_call
= trace_panic_handler
,
3972 .priority
= 150 /* priority: INT_MAX >= x >= 0 */
3975 static int trace_die_handler(struct notifier_block
*self
,
3981 if (ftrace_dump_on_oops
)
3990 static struct notifier_block trace_die_notifier
= {
3991 .notifier_call
= trace_die_handler
,
3996 * printk is set to max of 1024, we really don't need it that big.
3997 * Nothing should be printing 1000 characters anyway.
3999 #define TRACE_MAX_PRINT 1000
4002 * Define here KERN_TRACE so that we have one place to modify
4003 * it if we decide to change what log level the ftrace dump
4006 #define KERN_TRACE KERN_EMERG
4009 trace_printk_seq(struct trace_seq
*s
)
4011 /* Probably should print a warning here. */
4015 /* should be zero ended, but we are paranoid. */
4016 s
->buffer
[s
->len
] = 0;
4018 printk(KERN_TRACE
"%s", s
->buffer
);
4023 void ftrace_dump(void)
4025 static DEFINE_SPINLOCK(ftrace_dump_lock
);
4026 /* use static because iter can be a bit big for the stack */
4027 static struct trace_iterator iter
;
4028 static int dump_ran
;
4029 unsigned long flags
;
4033 spin_lock_irqsave(&ftrace_dump_lock
, flags
);
4039 /* No turning back! */
4043 for_each_tracing_cpu(cpu
) {
4044 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
4047 /* don't look at user memory in panic mode */
4048 trace_flags
&= ~TRACE_ITER_SYM_USEROBJ
;
4050 printk(KERN_TRACE
"Dumping ftrace buffer:\n");
4052 /* Simulate the iterator */
4053 iter
.tr
= &global_trace
;
4054 iter
.trace
= current_trace
;
4055 iter
.cpu_file
= TRACE_PIPE_ALL_CPU
;
4058 * We need to stop all tracing on all CPUS to read the
4059 * the next buffer. This is a bit expensive, but is
4060 * not done often. We fill all what we can read,
4061 * and then release the locks again.
4064 while (!trace_empty(&iter
)) {
4067 printk(KERN_TRACE
"---------------------------------\n");
4071 /* reset all but tr, trace, and overruns */
4072 memset(&iter
.seq
, 0,
4073 sizeof(struct trace_iterator
) -
4074 offsetof(struct trace_iterator
, seq
));
4075 iter
.iter_flags
|= TRACE_FILE_LAT_FMT
;
4078 if (find_next_entry_inc(&iter
) != NULL
) {
4079 print_trace_line(&iter
);
4080 trace_consume(&iter
);
4083 trace_printk_seq(&iter
.seq
);
4087 printk(KERN_TRACE
" (ftrace buffer empty)\n");
4089 printk(KERN_TRACE
"---------------------------------\n");
4092 spin_unlock_irqrestore(&ftrace_dump_lock
, flags
);
4095 __init
static int tracer_alloc_buffers(void)
4097 struct trace_array_cpu
*data
;
4102 if (!alloc_cpumask_var(&tracing_buffer_mask
, GFP_KERNEL
))
4105 if (!alloc_cpumask_var(&tracing_cpumask
, GFP_KERNEL
))
4106 goto out_free_buffer_mask
;
4108 if (!alloc_cpumask_var(&tracing_reader_cpumask
, GFP_KERNEL
))
4109 goto out_free_tracing_cpumask
;
4111 /* To save memory, keep the ring buffer size to its minimum */
4112 if (ring_buffer_expanded
)
4113 ring_buf_size
= trace_buf_size
;
4117 cpumask_copy(tracing_buffer_mask
, cpu_possible_mask
);
4118 cpumask_copy(tracing_cpumask
, cpu_all_mask
);
4119 cpumask_clear(tracing_reader_cpumask
);
4121 /* TODO: make the number of buffers hot pluggable with CPUS */
4122 global_trace
.buffer
= ring_buffer_alloc(ring_buf_size
,
4123 TRACE_BUFFER_FLAGS
);
4124 if (!global_trace
.buffer
) {
4125 printk(KERN_ERR
"tracer: failed to allocate ring buffer!\n");
4127 goto out_free_cpumask
;
4129 global_trace
.entries
= ring_buffer_size(global_trace
.buffer
);
4132 #ifdef CONFIG_TRACER_MAX_TRACE
4133 max_tr
.buffer
= ring_buffer_alloc(ring_buf_size
,
4134 TRACE_BUFFER_FLAGS
);
4135 if (!max_tr
.buffer
) {
4136 printk(KERN_ERR
"tracer: failed to allocate max ring buffer!\n");
4138 ring_buffer_free(global_trace
.buffer
);
4139 goto out_free_cpumask
;
4141 max_tr
.entries
= ring_buffer_size(max_tr
.buffer
);
4142 WARN_ON(max_tr
.entries
!= global_trace
.entries
);
4145 /* Allocate the first page for all buffers */
4146 for_each_tracing_cpu(i
) {
4147 data
= global_trace
.data
[i
] = &per_cpu(global_trace_cpu
, i
);
4148 max_tr
.data
[i
] = &per_cpu(max_data
, i
);
4151 trace_init_cmdlines();
4153 register_tracer(&nop_trace
);
4154 current_trace
= &nop_trace
;
4155 #ifdef CONFIG_BOOT_TRACER
4156 register_tracer(&boot_tracer
);
4158 /* All seems OK, enable tracing */
4159 tracing_disabled
= 0;
4161 atomic_notifier_chain_register(&panic_notifier_list
,
4162 &trace_panic_notifier
);
4164 register_die_notifier(&trace_die_notifier
);
4168 free_cpumask_var(tracing_reader_cpumask
);
4169 out_free_tracing_cpumask
:
4170 free_cpumask_var(tracing_cpumask
);
4171 out_free_buffer_mask
:
4172 free_cpumask_var(tracing_buffer_mask
);
4177 __init
static int clear_boot_tracer(void)
4180 * The default tracer at boot buffer is an init section.
4181 * This function is called in lateinit. If we did not
4182 * find the boot tracer, then clear it out, to prevent
4183 * later registration from accessing the buffer that is
4184 * about to be freed.
4186 if (!default_bootup_tracer
)
4189 printk(KERN_INFO
"ftrace bootup tracer '%s' not registered.\n",
4190 default_bootup_tracer
);
4191 default_bootup_tracer
= NULL
;
4196 early_initcall(tracer_alloc_buffers
);
4197 fs_initcall(tracer_init_debugfs
);
4198 late_initcall(clear_boot_tracer
);