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 <generated/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/string.h>
34 #include <linux/rwsem.h>
35 #include <linux/slab.h>
36 #include <linux/ctype.h>
37 #include <linux/init.h>
38 #include <linux/poll.h>
42 #include "trace_output.h"
44 #define TRACE_BUFFER_FLAGS (RB_FL_OVERWRITE)
47 * On boot up, the ring buffer is set to the minimum size, so that
48 * we do not waste memory on systems that are not using tracing.
50 int ring_buffer_expanded
;
53 * We need to change this state when a selftest is running.
54 * A selftest will lurk into the ring-buffer to count the
55 * entries inserted during the selftest although some concurrent
56 * insertions into the ring-buffer such as trace_printk could occurred
57 * at the same time, giving false positive or negative results.
59 static bool __read_mostly tracing_selftest_running
;
62 * If a tracer is running, we do not want to run SELFTEST.
64 bool __read_mostly tracing_selftest_disabled
;
66 /* For tracers that don't implement custom flags */
67 static struct tracer_opt dummy_tracer_opt
[] = {
71 static struct tracer_flags dummy_tracer_flags
= {
73 .opts
= dummy_tracer_opt
76 static int dummy_set_flag(u32 old_flags
, u32 bit
, int set
)
82 * Kill all tracing for good (never come back).
83 * It is initialized to 1 but will turn to zero if the initialization
84 * of the tracer is successful. But that is the only place that sets
87 static int tracing_disabled
= 1;
89 DEFINE_PER_CPU(int, ftrace_cpu_disabled
);
91 static inline void ftrace_disable_cpu(void)
94 __this_cpu_inc(ftrace_cpu_disabled
);
97 static inline void ftrace_enable_cpu(void)
99 __this_cpu_dec(ftrace_cpu_disabled
);
103 cpumask_var_t __read_mostly tracing_buffer_mask
;
106 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
108 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
109 * is set, then ftrace_dump is called. This will output the contents
110 * of the ftrace buffers to the console. This is very useful for
111 * capturing traces that lead to crashes and outputing it to a
114 * It is default off, but you can enable it with either specifying
115 * "ftrace_dump_on_oops" in the kernel command line, or setting
116 * /proc/sys/kernel/ftrace_dump_on_oops
117 * Set 1 if you want to dump buffers of all CPUs
118 * Set 2 if you want to dump the buffer of the CPU that triggered oops
121 enum ftrace_dump_mode ftrace_dump_on_oops
;
123 static int tracing_set_tracer(const char *buf
);
125 #define MAX_TRACER_SIZE 100
126 static char bootup_tracer_buf
[MAX_TRACER_SIZE
] __initdata
;
127 static char *default_bootup_tracer
;
129 static int __init
set_cmdline_ftrace(char *str
)
131 strncpy(bootup_tracer_buf
, str
, MAX_TRACER_SIZE
);
132 default_bootup_tracer
= bootup_tracer_buf
;
133 /* We are using ftrace early, expand it */
134 ring_buffer_expanded
= 1;
137 __setup("ftrace=", set_cmdline_ftrace
);
139 static int __init
set_ftrace_dump_on_oops(char *str
)
141 if (*str
++ != '=' || !*str
) {
142 ftrace_dump_on_oops
= DUMP_ALL
;
146 if (!strcmp("orig_cpu", str
)) {
147 ftrace_dump_on_oops
= DUMP_ORIG
;
153 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops
);
155 unsigned long long ns2usecs(cycle_t nsec
)
163 * The global_trace is the descriptor that holds the tracing
164 * buffers for the live tracing. For each CPU, it contains
165 * a link list of pages that will store trace entries. The
166 * page descriptor of the pages in the memory is used to hold
167 * the link list by linking the lru item in the page descriptor
168 * to each of the pages in the buffer per CPU.
170 * For each active CPU there is a data field that holds the
171 * pages for the buffer for that CPU. Each CPU has the same number
172 * of pages allocated for its buffer.
174 static struct trace_array global_trace
;
176 static DEFINE_PER_CPU(struct trace_array_cpu
, global_trace_cpu
);
178 int filter_current_check_discard(struct ring_buffer
*buffer
,
179 struct ftrace_event_call
*call
, void *rec
,
180 struct ring_buffer_event
*event
)
182 return filter_check_discard(call
, rec
, buffer
, event
);
184 EXPORT_SYMBOL_GPL(filter_current_check_discard
);
186 cycle_t
ftrace_now(int cpu
)
190 /* Early boot up does not have a buffer yet */
191 if (!global_trace
.buffer
)
192 return trace_clock_local();
194 ts
= ring_buffer_time_stamp(global_trace
.buffer
, cpu
);
195 ring_buffer_normalize_time_stamp(global_trace
.buffer
, cpu
, &ts
);
201 * The max_tr is used to snapshot the global_trace when a maximum
202 * latency is reached. Some tracers will use this to store a maximum
203 * trace while it continues examining live traces.
205 * The buffers for the max_tr are set up the same as the global_trace.
206 * When a snapshot is taken, the link list of the max_tr is swapped
207 * with the link list of the global_trace and the buffers are reset for
208 * the global_trace so the tracing can continue.
210 static struct trace_array max_tr
;
212 static DEFINE_PER_CPU(struct trace_array_cpu
, max_tr_data
);
214 /* tracer_enabled is used to toggle activation of a tracer */
215 static int tracer_enabled
= 1;
218 * tracing_is_enabled - return tracer_enabled status
220 * This function is used by other tracers to know the status
221 * of the tracer_enabled flag. Tracers may use this function
222 * to know if it should enable their features when starting
223 * up. See irqsoff tracer for an example (start_irqsoff_tracer).
225 int tracing_is_enabled(void)
227 return tracer_enabled
;
231 * trace_buf_size is the size in bytes that is allocated
232 * for a buffer. Note, the number of bytes is always rounded
235 * This number is purposely set to a low number of 16384.
236 * If the dump on oops happens, it will be much appreciated
237 * to not have to wait for all that output. Anyway this can be
238 * boot time and run time configurable.
240 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
242 static unsigned long trace_buf_size
= TRACE_BUF_SIZE_DEFAULT
;
244 /* trace_types holds a link list of available tracers. */
245 static struct tracer
*trace_types __read_mostly
;
247 /* current_trace points to the tracer that is currently active */
248 static struct tracer
*current_trace __read_mostly
;
251 * trace_types_lock is used to protect the trace_types list.
253 static DEFINE_MUTEX(trace_types_lock
);
256 * serialize the access of the ring buffer
258 * ring buffer serializes readers, but it is low level protection.
259 * The validity of the events (which returns by ring_buffer_peek() ..etc)
260 * are not protected by ring buffer.
262 * The content of events may become garbage if we allow other process consumes
263 * these events concurrently:
264 * A) the page of the consumed events may become a normal page
265 * (not reader page) in ring buffer, and this page will be rewrited
266 * by events producer.
267 * B) The page of the consumed events may become a page for splice_read,
268 * and this page will be returned to system.
270 * These primitives allow multi process access to different cpu ring buffer
273 * These primitives don't distinguish read-only and read-consume access.
274 * Multi read-only access are also serialized.
278 static DECLARE_RWSEM(all_cpu_access_lock
);
279 static DEFINE_PER_CPU(struct mutex
, cpu_access_lock
);
281 static inline void trace_access_lock(int cpu
)
283 if (cpu
== TRACE_PIPE_ALL_CPU
) {
284 /* gain it for accessing the whole ring buffer. */
285 down_write(&all_cpu_access_lock
);
287 /* gain it for accessing a cpu ring buffer. */
289 /* Firstly block other trace_access_lock(TRACE_PIPE_ALL_CPU). */
290 down_read(&all_cpu_access_lock
);
292 /* Secondly block other access to this @cpu ring buffer. */
293 mutex_lock(&per_cpu(cpu_access_lock
, cpu
));
297 static inline void trace_access_unlock(int cpu
)
299 if (cpu
== TRACE_PIPE_ALL_CPU
) {
300 up_write(&all_cpu_access_lock
);
302 mutex_unlock(&per_cpu(cpu_access_lock
, cpu
));
303 up_read(&all_cpu_access_lock
);
307 static inline void trace_access_lock_init(void)
311 for_each_possible_cpu(cpu
)
312 mutex_init(&per_cpu(cpu_access_lock
, cpu
));
317 static DEFINE_MUTEX(access_lock
);
319 static inline void trace_access_lock(int cpu
)
322 mutex_lock(&access_lock
);
325 static inline void trace_access_unlock(int cpu
)
328 mutex_unlock(&access_lock
);
331 static inline void trace_access_lock_init(void)
337 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
338 static DECLARE_WAIT_QUEUE_HEAD(trace_wait
);
340 /* trace_flags holds trace_options default values */
341 unsigned long trace_flags
= TRACE_ITER_PRINT_PARENT
| TRACE_ITER_PRINTK
|
342 TRACE_ITER_ANNOTATE
| TRACE_ITER_CONTEXT_INFO
| TRACE_ITER_SLEEP_TIME
|
343 TRACE_ITER_GRAPH_TIME
| TRACE_ITER_RECORD_CMD
;
345 static int trace_stop_count
;
346 static DEFINE_SPINLOCK(tracing_start_lock
);
349 * trace_wake_up - wake up tasks waiting for trace input
351 * Simply wakes up any task that is blocked on the trace_wait
352 * queue. These is used with trace_poll for tasks polling the trace.
354 void trace_wake_up(void)
358 if (trace_flags
& TRACE_ITER_BLOCK
)
361 * The runqueue_is_locked() can fail, but this is the best we
365 if (!runqueue_is_locked(cpu
))
366 wake_up(&trace_wait
);
370 static int __init
set_buf_size(char *str
)
372 unsigned long buf_size
;
376 buf_size
= memparse(str
, &str
);
377 /* nr_entries can not be zero */
380 trace_buf_size
= buf_size
;
383 __setup("trace_buf_size=", set_buf_size
);
385 static int __init
set_tracing_thresh(char *str
)
387 unsigned long threshhold
;
392 ret
= strict_strtoul(str
, 0, &threshhold
);
395 tracing_thresh
= threshhold
* 1000;
398 __setup("tracing_thresh=", set_tracing_thresh
);
400 unsigned long nsecs_to_usecs(unsigned long nsecs
)
405 /* These must match the bit postions in trace_iterator_flags */
406 static const char *trace_options
[] = {
435 { trace_clock_local
, "local" },
436 { trace_clock_global
, "global" },
442 * trace_parser_get_init - gets the buffer for trace parser
444 int trace_parser_get_init(struct trace_parser
*parser
, int size
)
446 memset(parser
, 0, sizeof(*parser
));
448 parser
->buffer
= kmalloc(size
, GFP_KERNEL
);
457 * trace_parser_put - frees the buffer for trace parser
459 void trace_parser_put(struct trace_parser
*parser
)
461 kfree(parser
->buffer
);
465 * trace_get_user - reads the user input string separated by space
466 * (matched by isspace(ch))
468 * For each string found the 'struct trace_parser' is updated,
469 * and the function returns.
471 * Returns number of bytes read.
473 * See kernel/trace/trace.h for 'struct trace_parser' details.
475 int trace_get_user(struct trace_parser
*parser
, const char __user
*ubuf
,
476 size_t cnt
, loff_t
*ppos
)
483 trace_parser_clear(parser
);
485 ret
= get_user(ch
, ubuf
++);
493 * The parser is not finished with the last write,
494 * continue reading the user input without skipping spaces.
497 /* skip white space */
498 while (cnt
&& isspace(ch
)) {
499 ret
= get_user(ch
, ubuf
++);
506 /* only spaces were written */
516 /* read the non-space input */
517 while (cnt
&& !isspace(ch
)) {
518 if (parser
->idx
< parser
->size
- 1)
519 parser
->buffer
[parser
->idx
++] = ch
;
524 ret
= get_user(ch
, ubuf
++);
531 /* We either got finished input or we have to wait for another call. */
533 parser
->buffer
[parser
->idx
] = 0;
534 parser
->cont
= false;
537 parser
->buffer
[parser
->idx
++] = ch
;
547 ssize_t
trace_seq_to_user(struct trace_seq
*s
, char __user
*ubuf
, size_t cnt
)
555 if (s
->len
<= s
->readpos
)
558 len
= s
->len
- s
->readpos
;
561 ret
= copy_to_user(ubuf
, s
->buffer
+ s
->readpos
, cnt
);
571 static ssize_t
trace_seq_to_buffer(struct trace_seq
*s
, void *buf
, size_t cnt
)
576 if (s
->len
<= s
->readpos
)
579 len
= s
->len
- s
->readpos
;
582 ret
= memcpy(buf
, s
->buffer
+ s
->readpos
, cnt
);
591 * ftrace_max_lock is used to protect the swapping of buffers
592 * when taking a max snapshot. The buffers themselves are
593 * protected by per_cpu spinlocks. But the action of the swap
594 * needs its own lock.
596 * This is defined as a arch_spinlock_t in order to help
597 * with performance when lockdep debugging is enabled.
599 * It is also used in other places outside the update_max_tr
600 * so it needs to be defined outside of the
601 * CONFIG_TRACER_MAX_TRACE.
603 static arch_spinlock_t ftrace_max_lock
=
604 (arch_spinlock_t
)__ARCH_SPIN_LOCK_UNLOCKED
;
606 unsigned long __read_mostly tracing_thresh
;
608 #ifdef CONFIG_TRACER_MAX_TRACE
609 unsigned long __read_mostly tracing_max_latency
;
612 * Copy the new maximum trace into the separate maximum-trace
613 * structure. (this way the maximum trace is permanently saved,
614 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
617 __update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
619 struct trace_array_cpu
*data
= tr
->data
[cpu
];
620 struct trace_array_cpu
*max_data
;
623 max_tr
.time_start
= data
->preempt_timestamp
;
625 max_data
= max_tr
.data
[cpu
];
626 max_data
->saved_latency
= tracing_max_latency
;
627 max_data
->critical_start
= data
->critical_start
;
628 max_data
->critical_end
= data
->critical_end
;
630 memcpy(max_data
->comm
, tsk
->comm
, TASK_COMM_LEN
);
631 max_data
->pid
= tsk
->pid
;
632 max_data
->uid
= task_uid(tsk
);
633 max_data
->nice
= tsk
->static_prio
- 20 - MAX_RT_PRIO
;
634 max_data
->policy
= tsk
->policy
;
635 max_data
->rt_priority
= tsk
->rt_priority
;
637 /* record this tasks comm */
638 tracing_record_cmdline(tsk
);
642 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
644 * @tsk: the task with the latency
645 * @cpu: The cpu that initiated the trace.
647 * Flip the buffers between the @tr and the max_tr and record information
648 * about which task was the cause of this latency.
651 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
653 struct ring_buffer
*buf
= tr
->buffer
;
655 if (trace_stop_count
)
658 WARN_ON_ONCE(!irqs_disabled());
659 if (!current_trace
->use_max_tr
) {
663 arch_spin_lock(&ftrace_max_lock
);
665 tr
->buffer
= max_tr
.buffer
;
668 __update_max_tr(tr
, tsk
, cpu
);
669 arch_spin_unlock(&ftrace_max_lock
);
673 * update_max_tr_single - only copy one trace over, and reset the rest
675 * @tsk - task with the latency
676 * @cpu - the cpu of the buffer to copy.
678 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
681 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
685 if (trace_stop_count
)
688 WARN_ON_ONCE(!irqs_disabled());
689 if (!current_trace
->use_max_tr
) {
694 arch_spin_lock(&ftrace_max_lock
);
696 ftrace_disable_cpu();
698 ret
= ring_buffer_swap_cpu(max_tr
.buffer
, tr
->buffer
, cpu
);
702 * We failed to swap the buffer due to a commit taking
703 * place on this CPU. We fail to record, but we reset
704 * the max trace buffer (no one writes directly to it)
705 * and flag that it failed.
707 trace_array_printk(&max_tr
, _THIS_IP_
,
708 "Failed to swap buffers due to commit in progress\n");
713 WARN_ON_ONCE(ret
&& ret
!= -EAGAIN
&& ret
!= -EBUSY
);
715 __update_max_tr(tr
, tsk
, cpu
);
716 arch_spin_unlock(&ftrace_max_lock
);
718 #endif /* CONFIG_TRACER_MAX_TRACE */
721 * register_tracer - register a tracer with the ftrace system.
722 * @type - the plugin for the tracer
724 * Register a new plugin tracer.
726 int register_tracer(struct tracer
*type
)
727 __releases(kernel_lock
)
728 __acquires(kernel_lock
)
734 pr_info("Tracer must have a name\n");
738 if (strlen(type
->name
) >= MAX_TRACER_SIZE
) {
739 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE
);
743 mutex_lock(&trace_types_lock
);
745 tracing_selftest_running
= true;
747 for (t
= trace_types
; t
; t
= t
->next
) {
748 if (strcmp(type
->name
, t
->name
) == 0) {
750 pr_info("Tracer %s already registered\n",
758 type
->set_flag
= &dummy_set_flag
;
760 type
->flags
= &dummy_tracer_flags
;
762 if (!type
->flags
->opts
)
763 type
->flags
->opts
= dummy_tracer_opt
;
764 if (!type
->wait_pipe
)
765 type
->wait_pipe
= default_wait_pipe
;
768 #ifdef CONFIG_FTRACE_STARTUP_TEST
769 if (type
->selftest
&& !tracing_selftest_disabled
) {
770 struct tracer
*saved_tracer
= current_trace
;
771 struct trace_array
*tr
= &global_trace
;
774 * Run a selftest on this tracer.
775 * Here we reset the trace buffer, and set the current
776 * tracer to be this tracer. The tracer can then run some
777 * internal tracing to verify that everything is in order.
778 * If we fail, we do not register this tracer.
780 tracing_reset_online_cpus(tr
);
782 current_trace
= type
;
783 /* the test is responsible for initializing and enabling */
784 pr_info("Testing tracer %s: ", type
->name
);
785 ret
= type
->selftest(type
, tr
);
786 /* the test is responsible for resetting too */
787 current_trace
= saved_tracer
;
789 printk(KERN_CONT
"FAILED!\n");
792 /* Only reset on passing, to avoid touching corrupted buffers */
793 tracing_reset_online_cpus(tr
);
795 printk(KERN_CONT
"PASSED\n");
799 type
->next
= trace_types
;
803 tracing_selftest_running
= false;
804 mutex_unlock(&trace_types_lock
);
806 if (ret
|| !default_bootup_tracer
)
809 if (strncmp(default_bootup_tracer
, type
->name
, MAX_TRACER_SIZE
))
812 printk(KERN_INFO
"Starting tracer '%s'\n", type
->name
);
813 /* Do we want this tracer to start on bootup? */
814 tracing_set_tracer(type
->name
);
815 default_bootup_tracer
= NULL
;
816 /* disable other selftests, since this will break it. */
817 tracing_selftest_disabled
= 1;
818 #ifdef CONFIG_FTRACE_STARTUP_TEST
819 printk(KERN_INFO
"Disabling FTRACE selftests due to running tracer '%s'\n",
827 void unregister_tracer(struct tracer
*type
)
831 mutex_lock(&trace_types_lock
);
832 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
836 pr_info("Tracer %s not registered\n", type
->name
);
842 if (type
== current_trace
&& tracer_enabled
) {
845 if (current_trace
->stop
)
846 current_trace
->stop(&global_trace
);
847 current_trace
= &nop_trace
;
850 mutex_unlock(&trace_types_lock
);
853 static void __tracing_reset(struct ring_buffer
*buffer
, int cpu
)
855 ftrace_disable_cpu();
856 ring_buffer_reset_cpu(buffer
, cpu
);
860 void tracing_reset(struct trace_array
*tr
, int cpu
)
862 struct ring_buffer
*buffer
= tr
->buffer
;
864 ring_buffer_record_disable(buffer
);
866 /* Make sure all commits have finished */
868 __tracing_reset(buffer
, cpu
);
870 ring_buffer_record_enable(buffer
);
873 void tracing_reset_online_cpus(struct trace_array
*tr
)
875 struct ring_buffer
*buffer
= tr
->buffer
;
878 ring_buffer_record_disable(buffer
);
880 /* Make sure all commits have finished */
883 tr
->time_start
= ftrace_now(tr
->cpu
);
885 for_each_online_cpu(cpu
)
886 __tracing_reset(buffer
, cpu
);
888 ring_buffer_record_enable(buffer
);
891 void tracing_reset_current(int cpu
)
893 tracing_reset(&global_trace
, cpu
);
896 void tracing_reset_current_online_cpus(void)
898 tracing_reset_online_cpus(&global_trace
);
901 #define SAVED_CMDLINES 128
902 #define NO_CMDLINE_MAP UINT_MAX
903 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
904 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
905 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
906 static int cmdline_idx
;
907 static arch_spinlock_t trace_cmdline_lock
= __ARCH_SPIN_LOCK_UNLOCKED
;
909 /* temporary disable recording */
910 static atomic_t trace_record_cmdline_disabled __read_mostly
;
912 static void trace_init_cmdlines(void)
914 memset(&map_pid_to_cmdline
, NO_CMDLINE_MAP
, sizeof(map_pid_to_cmdline
));
915 memset(&map_cmdline_to_pid
, NO_CMDLINE_MAP
, sizeof(map_cmdline_to_pid
));
919 int is_tracing_stopped(void)
921 return trace_stop_count
;
925 * ftrace_off_permanent - disable all ftrace code permanently
927 * This should only be called when a serious anomally has
928 * been detected. This will turn off the function tracing,
929 * ring buffers, and other tracing utilites. It takes no
930 * locks and can be called from any context.
932 void ftrace_off_permanent(void)
934 tracing_disabled
= 1;
936 tracing_off_permanent();
940 * tracing_start - quick start of the tracer
942 * If tracing is enabled but was stopped by tracing_stop,
943 * this will start the tracer back up.
945 void tracing_start(void)
947 struct ring_buffer
*buffer
;
950 if (tracing_disabled
)
953 spin_lock_irqsave(&tracing_start_lock
, flags
);
954 if (--trace_stop_count
) {
955 if (trace_stop_count
< 0) {
956 /* Someone screwed up their debugging */
958 trace_stop_count
= 0;
963 /* Prevent the buffers from switching */
964 arch_spin_lock(&ftrace_max_lock
);
966 buffer
= global_trace
.buffer
;
968 ring_buffer_record_enable(buffer
);
970 buffer
= max_tr
.buffer
;
972 ring_buffer_record_enable(buffer
);
974 arch_spin_unlock(&ftrace_max_lock
);
978 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
982 * tracing_stop - quick stop of the tracer
984 * Light weight way to stop tracing. Use in conjunction with
987 void tracing_stop(void)
989 struct ring_buffer
*buffer
;
993 spin_lock_irqsave(&tracing_start_lock
, flags
);
994 if (trace_stop_count
++)
997 /* Prevent the buffers from switching */
998 arch_spin_lock(&ftrace_max_lock
);
1000 buffer
= global_trace
.buffer
;
1002 ring_buffer_record_disable(buffer
);
1004 buffer
= max_tr
.buffer
;
1006 ring_buffer_record_disable(buffer
);
1008 arch_spin_unlock(&ftrace_max_lock
);
1011 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
1014 void trace_stop_cmdline_recording(void);
1016 static void trace_save_cmdline(struct task_struct
*tsk
)
1020 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
1024 * It's not the end of the world if we don't get
1025 * the lock, but we also don't want to spin
1026 * nor do we want to disable interrupts,
1027 * so if we miss here, then better luck next time.
1029 if (!arch_spin_trylock(&trace_cmdline_lock
))
1032 idx
= map_pid_to_cmdline
[tsk
->pid
];
1033 if (idx
== NO_CMDLINE_MAP
) {
1034 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
1037 * Check whether the cmdline buffer at idx has a pid
1038 * mapped. We are going to overwrite that entry so we
1039 * need to clear the map_pid_to_cmdline. Otherwise we
1040 * would read the new comm for the old pid.
1042 pid
= map_cmdline_to_pid
[idx
];
1043 if (pid
!= NO_CMDLINE_MAP
)
1044 map_pid_to_cmdline
[pid
] = NO_CMDLINE_MAP
;
1046 map_cmdline_to_pid
[idx
] = tsk
->pid
;
1047 map_pid_to_cmdline
[tsk
->pid
] = idx
;
1052 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
1054 arch_spin_unlock(&trace_cmdline_lock
);
1057 void trace_find_cmdline(int pid
, char comm
[])
1062 strcpy(comm
, "<idle>");
1066 if (WARN_ON_ONCE(pid
< 0)) {
1067 strcpy(comm
, "<XXX>");
1071 if (pid
> PID_MAX_DEFAULT
) {
1072 strcpy(comm
, "<...>");
1077 arch_spin_lock(&trace_cmdline_lock
);
1078 map
= map_pid_to_cmdline
[pid
];
1079 if (map
!= NO_CMDLINE_MAP
)
1080 strcpy(comm
, saved_cmdlines
[map
]);
1082 strcpy(comm
, "<...>");
1084 arch_spin_unlock(&trace_cmdline_lock
);
1088 void tracing_record_cmdline(struct task_struct
*tsk
)
1090 if (atomic_read(&trace_record_cmdline_disabled
) || !tracer_enabled
||
1094 trace_save_cmdline(tsk
);
1098 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
,
1101 struct task_struct
*tsk
= current
;
1103 entry
->preempt_count
= pc
& 0xff;
1104 entry
->pid
= (tsk
) ? tsk
->pid
: 0;
1105 entry
->lock_depth
= (tsk
) ? tsk
->lock_depth
: 0;
1107 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1108 (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
1110 TRACE_FLAG_IRQS_NOSUPPORT
|
1112 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
1113 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
1114 (need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0);
1116 EXPORT_SYMBOL_GPL(tracing_generic_entry_update
);
1118 struct ring_buffer_event
*
1119 trace_buffer_lock_reserve(struct ring_buffer
*buffer
,
1122 unsigned long flags
, int pc
)
1124 struct ring_buffer_event
*event
;
1126 event
= ring_buffer_lock_reserve(buffer
, len
);
1127 if (event
!= NULL
) {
1128 struct trace_entry
*ent
= ring_buffer_event_data(event
);
1130 tracing_generic_entry_update(ent
, flags
, pc
);
1138 __trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1139 struct ring_buffer_event
*event
,
1140 unsigned long flags
, int pc
,
1143 ring_buffer_unlock_commit(buffer
, event
);
1145 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1146 ftrace_trace_userstack(buffer
, flags
, pc
);
1152 void trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1153 struct ring_buffer_event
*event
,
1154 unsigned long flags
, int pc
)
1156 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
, 1);
1159 struct ring_buffer_event
*
1160 trace_current_buffer_lock_reserve(struct ring_buffer
**current_rb
,
1161 int type
, unsigned long len
,
1162 unsigned long flags
, int pc
)
1164 *current_rb
= global_trace
.buffer
;
1165 return trace_buffer_lock_reserve(*current_rb
,
1166 type
, len
, flags
, pc
);
1168 EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve
);
1170 void trace_current_buffer_unlock_commit(struct ring_buffer
*buffer
,
1171 struct ring_buffer_event
*event
,
1172 unsigned long flags
, int pc
)
1174 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
, 1);
1176 EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit
);
1178 void trace_nowake_buffer_unlock_commit(struct ring_buffer
*buffer
,
1179 struct ring_buffer_event
*event
,
1180 unsigned long flags
, int pc
)
1182 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
, 0);
1184 EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit
);
1186 void trace_current_buffer_discard_commit(struct ring_buffer
*buffer
,
1187 struct ring_buffer_event
*event
)
1189 ring_buffer_discard_commit(buffer
, event
);
1191 EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit
);
1194 trace_function(struct trace_array
*tr
,
1195 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
1198 struct ftrace_event_call
*call
= &event_function
;
1199 struct ring_buffer
*buffer
= tr
->buffer
;
1200 struct ring_buffer_event
*event
;
1201 struct ftrace_entry
*entry
;
1203 /* If we are reading the ring buffer, don't trace */
1204 if (unlikely(__this_cpu_read(ftrace_cpu_disabled
)))
1207 event
= trace_buffer_lock_reserve(buffer
, TRACE_FN
, sizeof(*entry
),
1211 entry
= ring_buffer_event_data(event
);
1213 entry
->parent_ip
= parent_ip
;
1215 if (!filter_check_discard(call
, entry
, buffer
, event
))
1216 ring_buffer_unlock_commit(buffer
, event
);
1220 ftrace(struct trace_array
*tr
, struct trace_array_cpu
*data
,
1221 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
1224 if (likely(!atomic_read(&data
->disabled
)))
1225 trace_function(tr
, ip
, parent_ip
, flags
, pc
);
1228 #ifdef CONFIG_STACKTRACE
1229 static void __ftrace_trace_stack(struct ring_buffer
*buffer
,
1230 unsigned long flags
,
1233 struct ftrace_event_call
*call
= &event_kernel_stack
;
1234 struct ring_buffer_event
*event
;
1235 struct stack_entry
*entry
;
1236 struct stack_trace trace
;
1238 event
= trace_buffer_lock_reserve(buffer
, TRACE_STACK
,
1239 sizeof(*entry
), flags
, pc
);
1242 entry
= ring_buffer_event_data(event
);
1243 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
1245 trace
.nr_entries
= 0;
1246 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1248 trace
.entries
= entry
->caller
;
1250 save_stack_trace(&trace
);
1251 if (!filter_check_discard(call
, entry
, buffer
, event
))
1252 ring_buffer_unlock_commit(buffer
, event
);
1255 void ftrace_trace_stack(struct ring_buffer
*buffer
, unsigned long flags
,
1258 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1261 __ftrace_trace_stack(buffer
, flags
, skip
, pc
);
1264 void __trace_stack(struct trace_array
*tr
, unsigned long flags
, int skip
,
1267 __ftrace_trace_stack(tr
->buffer
, flags
, skip
, pc
);
1271 * trace_dump_stack - record a stack back trace in the trace buffer
1273 void trace_dump_stack(void)
1275 unsigned long flags
;
1277 if (tracing_disabled
|| tracing_selftest_running
)
1280 local_save_flags(flags
);
1282 /* skipping 3 traces, seems to get us at the caller of this function */
1283 __ftrace_trace_stack(global_trace
.buffer
, flags
, 3, preempt_count());
1286 static DEFINE_PER_CPU(int, user_stack_count
);
1289 ftrace_trace_userstack(struct ring_buffer
*buffer
, unsigned long flags
, int pc
)
1291 struct ftrace_event_call
*call
= &event_user_stack
;
1292 struct ring_buffer_event
*event
;
1293 struct userstack_entry
*entry
;
1294 struct stack_trace trace
;
1296 if (!(trace_flags
& TRACE_ITER_USERSTACKTRACE
))
1300 * NMIs can not handle page faults, even with fix ups.
1301 * The save user stack can (and often does) fault.
1303 if (unlikely(in_nmi()))
1307 * prevent recursion, since the user stack tracing may
1308 * trigger other kernel events.
1311 if (__this_cpu_read(user_stack_count
))
1314 __this_cpu_inc(user_stack_count
);
1318 event
= trace_buffer_lock_reserve(buffer
, TRACE_USER_STACK
,
1319 sizeof(*entry
), flags
, pc
);
1322 entry
= ring_buffer_event_data(event
);
1324 entry
->tgid
= current
->tgid
;
1325 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
1327 trace
.nr_entries
= 0;
1328 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1330 trace
.entries
= entry
->caller
;
1332 save_stack_trace_user(&trace
);
1333 if (!filter_check_discard(call
, entry
, buffer
, event
))
1334 ring_buffer_unlock_commit(buffer
, event
);
1336 __this_cpu_dec(user_stack_count
);
1343 static void __trace_userstack(struct trace_array
*tr
, unsigned long flags
)
1345 ftrace_trace_userstack(tr
, flags
, preempt_count());
1349 #endif /* CONFIG_STACKTRACE */
1352 * trace_vbprintk - write binary msg to tracing buffer
1355 int trace_vbprintk(unsigned long ip
, const char *fmt
, va_list args
)
1357 static arch_spinlock_t trace_buf_lock
=
1358 (arch_spinlock_t
)__ARCH_SPIN_LOCK_UNLOCKED
;
1359 static u32 trace_buf
[TRACE_BUF_SIZE
];
1361 struct ftrace_event_call
*call
= &event_bprint
;
1362 struct ring_buffer_event
*event
;
1363 struct ring_buffer
*buffer
;
1364 struct trace_array
*tr
= &global_trace
;
1365 struct trace_array_cpu
*data
;
1366 struct bprint_entry
*entry
;
1367 unsigned long flags
;
1369 int cpu
, len
= 0, size
, pc
;
1371 if (unlikely(tracing_selftest_running
|| tracing_disabled
))
1374 /* Don't pollute graph traces with trace_vprintk internals */
1375 pause_graph_tracing();
1377 pc
= preempt_count();
1378 preempt_disable_notrace();
1379 cpu
= raw_smp_processor_id();
1380 data
= tr
->data
[cpu
];
1382 disable
= atomic_inc_return(&data
->disabled
);
1383 if (unlikely(disable
!= 1))
1386 /* Lockdep uses trace_printk for lock tracing */
1387 local_irq_save(flags
);
1388 arch_spin_lock(&trace_buf_lock
);
1389 len
= vbin_printf(trace_buf
, TRACE_BUF_SIZE
, fmt
, args
);
1391 if (len
> TRACE_BUF_SIZE
|| len
< 0)
1394 size
= sizeof(*entry
) + sizeof(u32
) * len
;
1395 buffer
= tr
->buffer
;
1396 event
= trace_buffer_lock_reserve(buffer
, TRACE_BPRINT
, size
,
1400 entry
= ring_buffer_event_data(event
);
1404 memcpy(entry
->buf
, trace_buf
, sizeof(u32
) * len
);
1405 if (!filter_check_discard(call
, entry
, buffer
, event
)) {
1406 ring_buffer_unlock_commit(buffer
, event
);
1407 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1411 arch_spin_unlock(&trace_buf_lock
);
1412 local_irq_restore(flags
);
1415 atomic_dec_return(&data
->disabled
);
1416 preempt_enable_notrace();
1417 unpause_graph_tracing();
1421 EXPORT_SYMBOL_GPL(trace_vbprintk
);
1423 int trace_array_printk(struct trace_array
*tr
,
1424 unsigned long ip
, const char *fmt
, ...)
1429 if (!(trace_flags
& TRACE_ITER_PRINTK
))
1433 ret
= trace_array_vprintk(tr
, ip
, fmt
, ap
);
1438 int trace_array_vprintk(struct trace_array
*tr
,
1439 unsigned long ip
, const char *fmt
, va_list args
)
1441 static arch_spinlock_t trace_buf_lock
= __ARCH_SPIN_LOCK_UNLOCKED
;
1442 static char trace_buf
[TRACE_BUF_SIZE
];
1444 struct ftrace_event_call
*call
= &event_print
;
1445 struct ring_buffer_event
*event
;
1446 struct ring_buffer
*buffer
;
1447 struct trace_array_cpu
*data
;
1448 int cpu
, len
= 0, size
, pc
;
1449 struct print_entry
*entry
;
1450 unsigned long irq_flags
;
1453 if (tracing_disabled
|| tracing_selftest_running
)
1456 pc
= preempt_count();
1457 preempt_disable_notrace();
1458 cpu
= raw_smp_processor_id();
1459 data
= tr
->data
[cpu
];
1461 disable
= atomic_inc_return(&data
->disabled
);
1462 if (unlikely(disable
!= 1))
1465 pause_graph_tracing();
1466 raw_local_irq_save(irq_flags
);
1467 arch_spin_lock(&trace_buf_lock
);
1468 len
= vsnprintf(trace_buf
, TRACE_BUF_SIZE
, fmt
, args
);
1470 size
= sizeof(*entry
) + len
+ 1;
1471 buffer
= tr
->buffer
;
1472 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, size
,
1476 entry
= ring_buffer_event_data(event
);
1479 memcpy(&entry
->buf
, trace_buf
, len
);
1480 entry
->buf
[len
] = '\0';
1481 if (!filter_check_discard(call
, entry
, buffer
, event
)) {
1482 ring_buffer_unlock_commit(buffer
, event
);
1483 ftrace_trace_stack(buffer
, irq_flags
, 6, pc
);
1487 arch_spin_unlock(&trace_buf_lock
);
1488 raw_local_irq_restore(irq_flags
);
1489 unpause_graph_tracing();
1491 atomic_dec_return(&data
->disabled
);
1492 preempt_enable_notrace();
1497 int trace_vprintk(unsigned long ip
, const char *fmt
, va_list args
)
1499 return trace_array_vprintk(&global_trace
, ip
, fmt
, args
);
1501 EXPORT_SYMBOL_GPL(trace_vprintk
);
1503 static void trace_iterator_increment(struct trace_iterator
*iter
)
1505 /* Don't allow ftrace to trace into the ring buffers */
1506 ftrace_disable_cpu();
1509 if (iter
->buffer_iter
[iter
->cpu
])
1510 ring_buffer_read(iter
->buffer_iter
[iter
->cpu
], NULL
);
1512 ftrace_enable_cpu();
1515 static struct trace_entry
*
1516 peek_next_entry(struct trace_iterator
*iter
, int cpu
, u64
*ts
,
1517 unsigned long *lost_events
)
1519 struct ring_buffer_event
*event
;
1520 struct ring_buffer_iter
*buf_iter
= iter
->buffer_iter
[cpu
];
1522 /* Don't allow ftrace to trace into the ring buffers */
1523 ftrace_disable_cpu();
1526 event
= ring_buffer_iter_peek(buf_iter
, ts
);
1528 event
= ring_buffer_peek(iter
->tr
->buffer
, cpu
, ts
,
1531 ftrace_enable_cpu();
1533 return event
? ring_buffer_event_data(event
) : NULL
;
1536 static struct trace_entry
*
1537 __find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
,
1538 unsigned long *missing_events
, u64
*ent_ts
)
1540 struct ring_buffer
*buffer
= iter
->tr
->buffer
;
1541 struct trace_entry
*ent
, *next
= NULL
;
1542 unsigned long lost_events
= 0, next_lost
= 0;
1543 int cpu_file
= iter
->cpu_file
;
1544 u64 next_ts
= 0, ts
;
1549 * If we are in a per_cpu trace file, don't bother by iterating over
1550 * all cpu and peek directly.
1552 if (cpu_file
> TRACE_PIPE_ALL_CPU
) {
1553 if (ring_buffer_empty_cpu(buffer
, cpu_file
))
1555 ent
= peek_next_entry(iter
, cpu_file
, ent_ts
, missing_events
);
1557 *ent_cpu
= cpu_file
;
1562 for_each_tracing_cpu(cpu
) {
1564 if (ring_buffer_empty_cpu(buffer
, cpu
))
1567 ent
= peek_next_entry(iter
, cpu
, &ts
, &lost_events
);
1570 * Pick the entry with the smallest timestamp:
1572 if (ent
&& (!next
|| ts
< next_ts
)) {
1576 next_lost
= lost_events
;
1581 *ent_cpu
= next_cpu
;
1587 *missing_events
= next_lost
;
1592 /* Find the next real entry, without updating the iterator itself */
1593 struct trace_entry
*trace_find_next_entry(struct trace_iterator
*iter
,
1594 int *ent_cpu
, u64
*ent_ts
)
1596 return __find_next_entry(iter
, ent_cpu
, NULL
, ent_ts
);
1599 /* Find the next real entry, and increment the iterator to the next entry */
1600 void *trace_find_next_entry_inc(struct trace_iterator
*iter
)
1602 iter
->ent
= __find_next_entry(iter
, &iter
->cpu
,
1603 &iter
->lost_events
, &iter
->ts
);
1606 trace_iterator_increment(iter
);
1608 return iter
->ent
? iter
: NULL
;
1611 static void trace_consume(struct trace_iterator
*iter
)
1613 /* Don't allow ftrace to trace into the ring buffers */
1614 ftrace_disable_cpu();
1615 ring_buffer_consume(iter
->tr
->buffer
, iter
->cpu
, &iter
->ts
,
1616 &iter
->lost_events
);
1617 ftrace_enable_cpu();
1620 static void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1622 struct trace_iterator
*iter
= m
->private;
1626 WARN_ON_ONCE(iter
->leftover
);
1630 /* can't go backwards */
1635 ent
= trace_find_next_entry_inc(iter
);
1639 while (ent
&& iter
->idx
< i
)
1640 ent
= trace_find_next_entry_inc(iter
);
1647 void tracing_iter_reset(struct trace_iterator
*iter
, int cpu
)
1649 struct trace_array
*tr
= iter
->tr
;
1650 struct ring_buffer_event
*event
;
1651 struct ring_buffer_iter
*buf_iter
;
1652 unsigned long entries
= 0;
1655 tr
->data
[cpu
]->skipped_entries
= 0;
1657 if (!iter
->buffer_iter
[cpu
])
1660 buf_iter
= iter
->buffer_iter
[cpu
];
1661 ring_buffer_iter_reset(buf_iter
);
1664 * We could have the case with the max latency tracers
1665 * that a reset never took place on a cpu. This is evident
1666 * by the timestamp being before the start of the buffer.
1668 while ((event
= ring_buffer_iter_peek(buf_iter
, &ts
))) {
1669 if (ts
>= iter
->tr
->time_start
)
1672 ring_buffer_read(buf_iter
, NULL
);
1675 tr
->data
[cpu
]->skipped_entries
= entries
;
1679 * The current tracer is copied to avoid a global locking
1682 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
1684 struct trace_iterator
*iter
= m
->private;
1685 static struct tracer
*old_tracer
;
1686 int cpu_file
= iter
->cpu_file
;
1691 /* copy the tracer to avoid using a global lock all around */
1692 mutex_lock(&trace_types_lock
);
1693 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
1694 old_tracer
= current_trace
;
1695 *iter
->trace
= *current_trace
;
1697 mutex_unlock(&trace_types_lock
);
1699 atomic_inc(&trace_record_cmdline_disabled
);
1701 if (*pos
!= iter
->pos
) {
1706 ftrace_disable_cpu();
1708 if (cpu_file
== TRACE_PIPE_ALL_CPU
) {
1709 for_each_tracing_cpu(cpu
)
1710 tracing_iter_reset(iter
, cpu
);
1712 tracing_iter_reset(iter
, cpu_file
);
1714 ftrace_enable_cpu();
1717 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
1722 * If we overflowed the seq_file before, then we want
1723 * to just reuse the trace_seq buffer again.
1729 p
= s_next(m
, p
, &l
);
1733 trace_event_read_lock();
1734 trace_access_lock(cpu_file
);
1738 static void s_stop(struct seq_file
*m
, void *p
)
1740 struct trace_iterator
*iter
= m
->private;
1742 atomic_dec(&trace_record_cmdline_disabled
);
1743 trace_access_unlock(iter
->cpu_file
);
1744 trace_event_read_unlock();
1747 static void print_lat_help_header(struct seq_file
*m
)
1749 seq_puts(m
, "# _------=> CPU# \n");
1750 seq_puts(m
, "# / _-----=> irqs-off \n");
1751 seq_puts(m
, "# | / _----=> need-resched \n");
1752 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
1753 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
1754 seq_puts(m
, "# |||| /_--=> lock-depth \n");
1755 seq_puts(m
, "# |||||/ delay \n");
1756 seq_puts(m
, "# cmd pid |||||| time | caller \n");
1757 seq_puts(m
, "# \\ / |||||| \\ | / \n");
1760 static void print_func_help_header(struct seq_file
*m
)
1762 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1763 seq_puts(m
, "# | | | | |\n");
1768 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
1770 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1771 struct trace_array
*tr
= iter
->tr
;
1772 struct trace_array_cpu
*data
= tr
->data
[tr
->cpu
];
1773 struct tracer
*type
= current_trace
;
1774 unsigned long entries
= 0;
1775 unsigned long total
= 0;
1776 unsigned long count
;
1777 const char *name
= "preemption";
1784 for_each_tracing_cpu(cpu
) {
1785 count
= ring_buffer_entries_cpu(tr
->buffer
, cpu
);
1787 * If this buffer has skipped entries, then we hold all
1788 * entries for the trace and we need to ignore the
1789 * ones before the time stamp.
1791 if (tr
->data
[cpu
]->skipped_entries
) {
1792 count
-= tr
->data
[cpu
]->skipped_entries
;
1793 /* total is the same as the entries */
1797 ring_buffer_overrun_cpu(tr
->buffer
, cpu
);
1801 seq_printf(m
, "# %s latency trace v1.1.5 on %s\n",
1803 seq_puts(m
, "# -----------------------------------"
1804 "---------------------------------\n");
1805 seq_printf(m
, "# latency: %lu us, #%lu/%lu, CPU#%d |"
1806 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1807 nsecs_to_usecs(data
->saved_latency
),
1811 #if defined(CONFIG_PREEMPT_NONE)
1813 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1815 #elif defined(CONFIG_PREEMPT)
1820 /* These are reserved for later use */
1823 seq_printf(m
, " #P:%d)\n", num_online_cpus());
1827 seq_puts(m
, "# -----------------\n");
1828 seq_printf(m
, "# | task: %.16s-%d "
1829 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1830 data
->comm
, data
->pid
, data
->uid
, data
->nice
,
1831 data
->policy
, data
->rt_priority
);
1832 seq_puts(m
, "# -----------------\n");
1834 if (data
->critical_start
) {
1835 seq_puts(m
, "# => started at: ");
1836 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
1837 trace_print_seq(m
, &iter
->seq
);
1838 seq_puts(m
, "\n# => ended at: ");
1839 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
1840 trace_print_seq(m
, &iter
->seq
);
1841 seq_puts(m
, "\n#\n");
1847 static void test_cpu_buff_start(struct trace_iterator
*iter
)
1849 struct trace_seq
*s
= &iter
->seq
;
1851 if (!(trace_flags
& TRACE_ITER_ANNOTATE
))
1854 if (!(iter
->iter_flags
& TRACE_FILE_ANNOTATE
))
1857 if (cpumask_test_cpu(iter
->cpu
, iter
->started
))
1860 if (iter
->tr
->data
[iter
->cpu
]->skipped_entries
)
1863 cpumask_set_cpu(iter
->cpu
, iter
->started
);
1865 /* Don't print started cpu buffer for the first entry of the trace */
1867 trace_seq_printf(s
, "##### CPU %u buffer started ####\n",
1871 static enum print_line_t
print_trace_fmt(struct trace_iterator
*iter
)
1873 struct trace_seq
*s
= &iter
->seq
;
1874 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1875 struct trace_entry
*entry
;
1876 struct trace_event
*event
;
1880 test_cpu_buff_start(iter
);
1882 event
= ftrace_find_event(entry
->type
);
1884 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1885 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
1886 if (!trace_print_lat_context(iter
))
1889 if (!trace_print_context(iter
))
1895 return event
->funcs
->trace(iter
, sym_flags
, event
);
1897 if (!trace_seq_printf(s
, "Unknown type %d\n", entry
->type
))
1900 return TRACE_TYPE_HANDLED
;
1902 return TRACE_TYPE_PARTIAL_LINE
;
1905 static enum print_line_t
print_raw_fmt(struct trace_iterator
*iter
)
1907 struct trace_seq
*s
= &iter
->seq
;
1908 struct trace_entry
*entry
;
1909 struct trace_event
*event
;
1913 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1914 if (!trace_seq_printf(s
, "%d %d %llu ",
1915 entry
->pid
, iter
->cpu
, iter
->ts
))
1919 event
= ftrace_find_event(entry
->type
);
1921 return event
->funcs
->raw(iter
, 0, event
);
1923 if (!trace_seq_printf(s
, "%d ?\n", entry
->type
))
1926 return TRACE_TYPE_HANDLED
;
1928 return TRACE_TYPE_PARTIAL_LINE
;
1931 static enum print_line_t
print_hex_fmt(struct trace_iterator
*iter
)
1933 struct trace_seq
*s
= &iter
->seq
;
1934 unsigned char newline
= '\n';
1935 struct trace_entry
*entry
;
1936 struct trace_event
*event
;
1940 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1941 SEQ_PUT_HEX_FIELD_RET(s
, entry
->pid
);
1942 SEQ_PUT_HEX_FIELD_RET(s
, iter
->cpu
);
1943 SEQ_PUT_HEX_FIELD_RET(s
, iter
->ts
);
1946 event
= ftrace_find_event(entry
->type
);
1948 enum print_line_t ret
= event
->funcs
->hex(iter
, 0, event
);
1949 if (ret
!= TRACE_TYPE_HANDLED
)
1953 SEQ_PUT_FIELD_RET(s
, newline
);
1955 return TRACE_TYPE_HANDLED
;
1958 static enum print_line_t
print_bin_fmt(struct trace_iterator
*iter
)
1960 struct trace_seq
*s
= &iter
->seq
;
1961 struct trace_entry
*entry
;
1962 struct trace_event
*event
;
1966 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1967 SEQ_PUT_FIELD_RET(s
, entry
->pid
);
1968 SEQ_PUT_FIELD_RET(s
, iter
->cpu
);
1969 SEQ_PUT_FIELD_RET(s
, iter
->ts
);
1972 event
= ftrace_find_event(entry
->type
);
1973 return event
? event
->funcs
->binary(iter
, 0, event
) :
1977 int trace_empty(struct trace_iterator
*iter
)
1981 /* If we are looking at one CPU buffer, only check that one */
1982 if (iter
->cpu_file
!= TRACE_PIPE_ALL_CPU
) {
1983 cpu
= iter
->cpu_file
;
1984 if (iter
->buffer_iter
[cpu
]) {
1985 if (!ring_buffer_iter_empty(iter
->buffer_iter
[cpu
]))
1988 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
1994 for_each_tracing_cpu(cpu
) {
1995 if (iter
->buffer_iter
[cpu
]) {
1996 if (!ring_buffer_iter_empty(iter
->buffer_iter
[cpu
]))
1999 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
2007 /* Called with trace_event_read_lock() held. */
2008 enum print_line_t
print_trace_line(struct trace_iterator
*iter
)
2010 enum print_line_t ret
;
2012 if (iter
->lost_events
)
2013 trace_seq_printf(&iter
->seq
, "CPU:%d [LOST %lu EVENTS]\n",
2014 iter
->cpu
, iter
->lost_events
);
2016 if (iter
->trace
&& iter
->trace
->print_line
) {
2017 ret
= iter
->trace
->print_line(iter
);
2018 if (ret
!= TRACE_TYPE_UNHANDLED
)
2022 if (iter
->ent
->type
== TRACE_BPRINT
&&
2023 trace_flags
& TRACE_ITER_PRINTK
&&
2024 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2025 return trace_print_bprintk_msg_only(iter
);
2027 if (iter
->ent
->type
== TRACE_PRINT
&&
2028 trace_flags
& TRACE_ITER_PRINTK
&&
2029 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2030 return trace_print_printk_msg_only(iter
);
2032 if (trace_flags
& TRACE_ITER_BIN
)
2033 return print_bin_fmt(iter
);
2035 if (trace_flags
& TRACE_ITER_HEX
)
2036 return print_hex_fmt(iter
);
2038 if (trace_flags
& TRACE_ITER_RAW
)
2039 return print_raw_fmt(iter
);
2041 return print_trace_fmt(iter
);
2044 void trace_default_header(struct seq_file
*m
)
2046 struct trace_iterator
*iter
= m
->private;
2048 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
2049 /* print nothing if the buffers are empty */
2050 if (trace_empty(iter
))
2052 print_trace_header(m
, iter
);
2053 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2054 print_lat_help_header(m
);
2056 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2057 print_func_help_header(m
);
2061 static int s_show(struct seq_file
*m
, void *v
)
2063 struct trace_iterator
*iter
= v
;
2066 if (iter
->ent
== NULL
) {
2068 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
2071 if (iter
->trace
&& iter
->trace
->print_header
)
2072 iter
->trace
->print_header(m
);
2074 trace_default_header(m
);
2076 } else if (iter
->leftover
) {
2078 * If we filled the seq_file buffer earlier, we
2079 * want to just show it now.
2081 ret
= trace_print_seq(m
, &iter
->seq
);
2083 /* ret should this time be zero, but you never know */
2084 iter
->leftover
= ret
;
2087 print_trace_line(iter
);
2088 ret
= trace_print_seq(m
, &iter
->seq
);
2090 * If we overflow the seq_file buffer, then it will
2091 * ask us for this data again at start up.
2093 * ret is 0 if seq_file write succeeded.
2096 iter
->leftover
= ret
;
2102 static const struct seq_operations tracer_seq_ops
= {
2109 static struct trace_iterator
*
2110 __tracing_open(struct inode
*inode
, struct file
*file
)
2112 long cpu_file
= (long) inode
->i_private
;
2113 void *fail_ret
= ERR_PTR(-ENOMEM
);
2114 struct trace_iterator
*iter
;
2118 if (tracing_disabled
)
2119 return ERR_PTR(-ENODEV
);
2121 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2123 return ERR_PTR(-ENOMEM
);
2126 * We make a copy of the current tracer to avoid concurrent
2127 * changes on it while we are reading.
2129 mutex_lock(&trace_types_lock
);
2130 iter
->trace
= kzalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
2135 *iter
->trace
= *current_trace
;
2137 if (!zalloc_cpumask_var(&iter
->started
, GFP_KERNEL
))
2140 if (current_trace
&& current_trace
->print_max
)
2143 iter
->tr
= &global_trace
;
2145 mutex_init(&iter
->mutex
);
2146 iter
->cpu_file
= cpu_file
;
2148 /* Notify the tracer early; before we stop tracing. */
2149 if (iter
->trace
&& iter
->trace
->open
)
2150 iter
->trace
->open(iter
);
2152 /* Annotate start of buffers if we had overruns */
2153 if (ring_buffer_overruns(iter
->tr
->buffer
))
2154 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
2156 /* stop the trace while dumping */
2159 if (iter
->cpu_file
== TRACE_PIPE_ALL_CPU
) {
2160 for_each_tracing_cpu(cpu
) {
2161 iter
->buffer_iter
[cpu
] =
2162 ring_buffer_read_prepare(iter
->tr
->buffer
, cpu
);
2164 ring_buffer_read_prepare_sync();
2165 for_each_tracing_cpu(cpu
) {
2166 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2167 tracing_iter_reset(iter
, cpu
);
2170 cpu
= iter
->cpu_file
;
2171 iter
->buffer_iter
[cpu
] =
2172 ring_buffer_read_prepare(iter
->tr
->buffer
, cpu
);
2173 ring_buffer_read_prepare_sync();
2174 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2175 tracing_iter_reset(iter
, cpu
);
2178 ret
= seq_open(file
, &tracer_seq_ops
);
2180 fail_ret
= ERR_PTR(ret
);
2184 m
= file
->private_data
;
2187 mutex_unlock(&trace_types_lock
);
2192 for_each_tracing_cpu(cpu
) {
2193 if (iter
->buffer_iter
[cpu
])
2194 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
2196 free_cpumask_var(iter
->started
);
2199 mutex_unlock(&trace_types_lock
);
2206 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
2208 if (tracing_disabled
)
2211 filp
->private_data
= inode
->i_private
;
2215 static int tracing_release(struct inode
*inode
, struct file
*file
)
2217 struct seq_file
*m
= file
->private_data
;
2218 struct trace_iterator
*iter
;
2221 if (!(file
->f_mode
& FMODE_READ
))
2226 mutex_lock(&trace_types_lock
);
2227 for_each_tracing_cpu(cpu
) {
2228 if (iter
->buffer_iter
[cpu
])
2229 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
2232 if (iter
->trace
&& iter
->trace
->close
)
2233 iter
->trace
->close(iter
);
2235 /* reenable tracing if it was previously enabled */
2237 mutex_unlock(&trace_types_lock
);
2239 seq_release(inode
, file
);
2240 mutex_destroy(&iter
->mutex
);
2241 free_cpumask_var(iter
->started
);
2247 static int tracing_open(struct inode
*inode
, struct file
*file
)
2249 struct trace_iterator
*iter
;
2252 /* If this file was open for write, then erase contents */
2253 if ((file
->f_mode
& FMODE_WRITE
) &&
2254 (file
->f_flags
& O_TRUNC
)) {
2255 long cpu
= (long) inode
->i_private
;
2257 if (cpu
== TRACE_PIPE_ALL_CPU
)
2258 tracing_reset_online_cpus(&global_trace
);
2260 tracing_reset(&global_trace
, cpu
);
2263 if (file
->f_mode
& FMODE_READ
) {
2264 iter
= __tracing_open(inode
, file
);
2266 ret
= PTR_ERR(iter
);
2267 else if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
2268 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
2274 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
2276 struct tracer
*t
= v
;
2286 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
2291 mutex_lock(&trace_types_lock
);
2292 for (t
= trace_types
; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
2298 static void t_stop(struct seq_file
*m
, void *p
)
2300 mutex_unlock(&trace_types_lock
);
2303 static int t_show(struct seq_file
*m
, void *v
)
2305 struct tracer
*t
= v
;
2310 seq_printf(m
, "%s", t
->name
);
2319 static const struct seq_operations show_traces_seq_ops
= {
2326 static int show_traces_open(struct inode
*inode
, struct file
*file
)
2328 if (tracing_disabled
)
2331 return seq_open(file
, &show_traces_seq_ops
);
2335 tracing_write_stub(struct file
*filp
, const char __user
*ubuf
,
2336 size_t count
, loff_t
*ppos
)
2341 static loff_t
tracing_seek(struct file
*file
, loff_t offset
, int origin
)
2343 if (file
->f_mode
& FMODE_READ
)
2344 return seq_lseek(file
, offset
, origin
);
2349 static const struct file_operations tracing_fops
= {
2350 .open
= tracing_open
,
2352 .write
= tracing_write_stub
,
2353 .llseek
= tracing_seek
,
2354 .release
= tracing_release
,
2357 static const struct file_operations show_traces_fops
= {
2358 .open
= show_traces_open
,
2360 .release
= seq_release
,
2361 .llseek
= seq_lseek
,
2365 * Only trace on a CPU if the bitmask is set:
2367 static cpumask_var_t tracing_cpumask
;
2370 * The tracer itself will not take this lock, but still we want
2371 * to provide a consistent cpumask to user-space:
2373 static DEFINE_MUTEX(tracing_cpumask_update_lock
);
2376 * Temporary storage for the character representation of the
2377 * CPU bitmask (and one more byte for the newline):
2379 static char mask_str
[NR_CPUS
+ 1];
2382 tracing_cpumask_read(struct file
*filp
, char __user
*ubuf
,
2383 size_t count
, loff_t
*ppos
)
2387 mutex_lock(&tracing_cpumask_update_lock
);
2389 len
= cpumask_scnprintf(mask_str
, count
, tracing_cpumask
);
2390 if (count
- len
< 2) {
2394 len
+= sprintf(mask_str
+ len
, "\n");
2395 count
= simple_read_from_buffer(ubuf
, count
, ppos
, mask_str
, NR_CPUS
+1);
2398 mutex_unlock(&tracing_cpumask_update_lock
);
2404 tracing_cpumask_write(struct file
*filp
, const char __user
*ubuf
,
2405 size_t count
, loff_t
*ppos
)
2408 cpumask_var_t tracing_cpumask_new
;
2410 if (!alloc_cpumask_var(&tracing_cpumask_new
, GFP_KERNEL
))
2413 err
= cpumask_parse_user(ubuf
, count
, tracing_cpumask_new
);
2417 mutex_lock(&tracing_cpumask_update_lock
);
2419 local_irq_disable();
2420 arch_spin_lock(&ftrace_max_lock
);
2421 for_each_tracing_cpu(cpu
) {
2423 * Increase/decrease the disabled counter if we are
2424 * about to flip a bit in the cpumask:
2426 if (cpumask_test_cpu(cpu
, tracing_cpumask
) &&
2427 !cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
2428 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
2430 if (!cpumask_test_cpu(cpu
, tracing_cpumask
) &&
2431 cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
2432 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
2435 arch_spin_unlock(&ftrace_max_lock
);
2438 cpumask_copy(tracing_cpumask
, tracing_cpumask_new
);
2440 mutex_unlock(&tracing_cpumask_update_lock
);
2441 free_cpumask_var(tracing_cpumask_new
);
2446 free_cpumask_var(tracing_cpumask_new
);
2451 static const struct file_operations tracing_cpumask_fops
= {
2452 .open
= tracing_open_generic
,
2453 .read
= tracing_cpumask_read
,
2454 .write
= tracing_cpumask_write
,
2455 .llseek
= generic_file_llseek
,
2458 static int tracing_trace_options_show(struct seq_file
*m
, void *v
)
2460 struct tracer_opt
*trace_opts
;
2464 mutex_lock(&trace_types_lock
);
2465 tracer_flags
= current_trace
->flags
->val
;
2466 trace_opts
= current_trace
->flags
->opts
;
2468 for (i
= 0; trace_options
[i
]; i
++) {
2469 if (trace_flags
& (1 << i
))
2470 seq_printf(m
, "%s\n", trace_options
[i
]);
2472 seq_printf(m
, "no%s\n", trace_options
[i
]);
2475 for (i
= 0; trace_opts
[i
].name
; i
++) {
2476 if (tracer_flags
& trace_opts
[i
].bit
)
2477 seq_printf(m
, "%s\n", trace_opts
[i
].name
);
2479 seq_printf(m
, "no%s\n", trace_opts
[i
].name
);
2481 mutex_unlock(&trace_types_lock
);
2486 static int __set_tracer_option(struct tracer
*trace
,
2487 struct tracer_flags
*tracer_flags
,
2488 struct tracer_opt
*opts
, int neg
)
2492 ret
= trace
->set_flag(tracer_flags
->val
, opts
->bit
, !neg
);
2497 tracer_flags
->val
&= ~opts
->bit
;
2499 tracer_flags
->val
|= opts
->bit
;
2503 /* Try to assign a tracer specific option */
2504 static int set_tracer_option(struct tracer
*trace
, char *cmp
, int neg
)
2506 struct tracer_flags
*tracer_flags
= trace
->flags
;
2507 struct tracer_opt
*opts
= NULL
;
2510 for (i
= 0; tracer_flags
->opts
[i
].name
; i
++) {
2511 opts
= &tracer_flags
->opts
[i
];
2513 if (strcmp(cmp
, opts
->name
) == 0)
2514 return __set_tracer_option(trace
, trace
->flags
,
2521 static void set_tracer_flags(unsigned int mask
, int enabled
)
2523 /* do nothing if flag is already set */
2524 if (!!(trace_flags
& mask
) == !!enabled
)
2528 trace_flags
|= mask
;
2530 trace_flags
&= ~mask
;
2532 if (mask
== TRACE_ITER_RECORD_CMD
)
2533 trace_event_enable_cmd_record(enabled
);
2537 tracing_trace_options_write(struct file
*filp
, const char __user
*ubuf
,
2538 size_t cnt
, loff_t
*ppos
)
2546 if (cnt
>= sizeof(buf
))
2549 if (copy_from_user(&buf
, ubuf
, cnt
))
2553 cmp
= strstrip(buf
);
2555 if (strncmp(cmp
, "no", 2) == 0) {
2560 for (i
= 0; trace_options
[i
]; i
++) {
2561 if (strcmp(cmp
, trace_options
[i
]) == 0) {
2562 set_tracer_flags(1 << i
, !neg
);
2567 /* If no option could be set, test the specific tracer options */
2568 if (!trace_options
[i
]) {
2569 mutex_lock(&trace_types_lock
);
2570 ret
= set_tracer_option(current_trace
, cmp
, neg
);
2571 mutex_unlock(&trace_types_lock
);
2581 static int tracing_trace_options_open(struct inode
*inode
, struct file
*file
)
2583 if (tracing_disabled
)
2585 return single_open(file
, tracing_trace_options_show
, NULL
);
2588 static const struct file_operations tracing_iter_fops
= {
2589 .open
= tracing_trace_options_open
,
2591 .llseek
= seq_lseek
,
2592 .release
= single_release
,
2593 .write
= tracing_trace_options_write
,
2596 static const char readme_msg
[] =
2597 "tracing mini-HOWTO:\n\n"
2598 "# mount -t debugfs nodev /sys/kernel/debug\n\n"
2599 "# cat /sys/kernel/debug/tracing/available_tracers\n"
2600 "wakeup preemptirqsoff preemptoff irqsoff function sched_switch nop\n\n"
2601 "# cat /sys/kernel/debug/tracing/current_tracer\n"
2603 "# echo sched_switch > /sys/kernel/debug/tracing/current_tracer\n"
2604 "# cat /sys/kernel/debug/tracing/current_tracer\n"
2606 "# cat /sys/kernel/debug/tracing/trace_options\n"
2607 "noprint-parent nosym-offset nosym-addr noverbose\n"
2608 "# echo print-parent > /sys/kernel/debug/tracing/trace_options\n"
2609 "# echo 1 > /sys/kernel/debug/tracing/tracing_enabled\n"
2610 "# cat /sys/kernel/debug/tracing/trace > /tmp/trace.txt\n"
2611 "# echo 0 > /sys/kernel/debug/tracing/tracing_enabled\n"
2615 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
2616 size_t cnt
, loff_t
*ppos
)
2618 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
2619 readme_msg
, strlen(readme_msg
));
2622 static const struct file_operations tracing_readme_fops
= {
2623 .open
= tracing_open_generic
,
2624 .read
= tracing_readme_read
,
2625 .llseek
= generic_file_llseek
,
2629 tracing_saved_cmdlines_read(struct file
*file
, char __user
*ubuf
,
2630 size_t cnt
, loff_t
*ppos
)
2639 file_buf
= kmalloc(SAVED_CMDLINES
*(16+TASK_COMM_LEN
), GFP_KERNEL
);
2643 buf_comm
= kmalloc(TASK_COMM_LEN
, GFP_KERNEL
);
2651 for (i
= 0; i
< SAVED_CMDLINES
; i
++) {
2654 pid
= map_cmdline_to_pid
[i
];
2655 if (pid
== -1 || pid
== NO_CMDLINE_MAP
)
2658 trace_find_cmdline(pid
, buf_comm
);
2659 r
= sprintf(buf
, "%d %s\n", pid
, buf_comm
);
2664 len
= simple_read_from_buffer(ubuf
, cnt
, ppos
,
2673 static const struct file_operations tracing_saved_cmdlines_fops
= {
2674 .open
= tracing_open_generic
,
2675 .read
= tracing_saved_cmdlines_read
,
2676 .llseek
= generic_file_llseek
,
2680 tracing_ctrl_read(struct file
*filp
, char __user
*ubuf
,
2681 size_t cnt
, loff_t
*ppos
)
2686 r
= sprintf(buf
, "%u\n", tracer_enabled
);
2687 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2691 tracing_ctrl_write(struct file
*filp
, const char __user
*ubuf
,
2692 size_t cnt
, loff_t
*ppos
)
2694 struct trace_array
*tr
= filp
->private_data
;
2699 if (cnt
>= sizeof(buf
))
2702 if (copy_from_user(&buf
, ubuf
, cnt
))
2707 ret
= strict_strtoul(buf
, 10, &val
);
2713 mutex_lock(&trace_types_lock
);
2714 if (tracer_enabled
^ val
) {
2717 if (current_trace
->start
)
2718 current_trace
->start(tr
);
2723 if (current_trace
->stop
)
2724 current_trace
->stop(tr
);
2727 mutex_unlock(&trace_types_lock
);
2735 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
2736 size_t cnt
, loff_t
*ppos
)
2738 char buf
[MAX_TRACER_SIZE
+2];
2741 mutex_lock(&trace_types_lock
);
2743 r
= sprintf(buf
, "%s\n", current_trace
->name
);
2745 r
= sprintf(buf
, "\n");
2746 mutex_unlock(&trace_types_lock
);
2748 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2751 int tracer_init(struct tracer
*t
, struct trace_array
*tr
)
2753 tracing_reset_online_cpus(tr
);
2757 static int tracing_resize_ring_buffer(unsigned long size
)
2762 * If kernel or user changes the size of the ring buffer
2763 * we use the size that was given, and we can forget about
2764 * expanding it later.
2766 ring_buffer_expanded
= 1;
2768 ret
= ring_buffer_resize(global_trace
.buffer
, size
);
2772 if (!current_trace
->use_max_tr
)
2775 ret
= ring_buffer_resize(max_tr
.buffer
, size
);
2779 r
= ring_buffer_resize(global_trace
.buffer
,
2780 global_trace
.entries
);
2783 * AARGH! We are left with different
2784 * size max buffer!!!!
2785 * The max buffer is our "snapshot" buffer.
2786 * When a tracer needs a snapshot (one of the
2787 * latency tracers), it swaps the max buffer
2788 * with the saved snap shot. We succeeded to
2789 * update the size of the main buffer, but failed to
2790 * update the size of the max buffer. But when we tried
2791 * to reset the main buffer to the original size, we
2792 * failed there too. This is very unlikely to
2793 * happen, but if it does, warn and kill all
2797 tracing_disabled
= 1;
2802 max_tr
.entries
= size
;
2804 global_trace
.entries
= size
;
2811 * tracing_update_buffers - used by tracing facility to expand ring buffers
2813 * To save on memory when the tracing is never used on a system with it
2814 * configured in. The ring buffers are set to a minimum size. But once
2815 * a user starts to use the tracing facility, then they need to grow
2816 * to their default size.
2818 * This function is to be called when a tracer is about to be used.
2820 int tracing_update_buffers(void)
2824 mutex_lock(&trace_types_lock
);
2825 if (!ring_buffer_expanded
)
2826 ret
= tracing_resize_ring_buffer(trace_buf_size
);
2827 mutex_unlock(&trace_types_lock
);
2832 struct trace_option_dentry
;
2834 static struct trace_option_dentry
*
2835 create_trace_option_files(struct tracer
*tracer
);
2838 destroy_trace_option_files(struct trace_option_dentry
*topts
);
2840 static int tracing_set_tracer(const char *buf
)
2842 static struct trace_option_dentry
*topts
;
2843 struct trace_array
*tr
= &global_trace
;
2847 mutex_lock(&trace_types_lock
);
2849 if (!ring_buffer_expanded
) {
2850 ret
= tracing_resize_ring_buffer(trace_buf_size
);
2856 for (t
= trace_types
; t
; t
= t
->next
) {
2857 if (strcmp(t
->name
, buf
) == 0)
2864 if (t
== current_trace
)
2867 trace_branch_disable();
2868 if (current_trace
&& current_trace
->reset
)
2869 current_trace
->reset(tr
);
2870 if (current_trace
&& current_trace
->use_max_tr
) {
2872 * We don't free the ring buffer. instead, resize it because
2873 * The max_tr ring buffer has some state (e.g. ring->clock) and
2874 * we want preserve it.
2876 ring_buffer_resize(max_tr
.buffer
, 1);
2879 destroy_trace_option_files(topts
);
2883 topts
= create_trace_option_files(current_trace
);
2884 if (current_trace
->use_max_tr
) {
2885 ret
= ring_buffer_resize(max_tr
.buffer
, global_trace
.entries
);
2888 max_tr
.entries
= global_trace
.entries
;
2892 ret
= tracer_init(t
, tr
);
2897 trace_branch_enable(tr
);
2899 mutex_unlock(&trace_types_lock
);
2905 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
2906 size_t cnt
, loff_t
*ppos
)
2908 char buf
[MAX_TRACER_SIZE
+1];
2915 if (cnt
> MAX_TRACER_SIZE
)
2916 cnt
= MAX_TRACER_SIZE
;
2918 if (copy_from_user(&buf
, ubuf
, cnt
))
2923 /* strip ending whitespace. */
2924 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
2927 err
= tracing_set_tracer(buf
);
2937 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
2938 size_t cnt
, loff_t
*ppos
)
2940 unsigned long *ptr
= filp
->private_data
;
2944 r
= snprintf(buf
, sizeof(buf
), "%ld\n",
2945 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
2946 if (r
> sizeof(buf
))
2948 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2952 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
2953 size_t cnt
, loff_t
*ppos
)
2955 unsigned long *ptr
= filp
->private_data
;
2960 if (cnt
>= sizeof(buf
))
2963 if (copy_from_user(&buf
, ubuf
, cnt
))
2968 ret
= strict_strtoul(buf
, 10, &val
);
2977 static int tracing_open_pipe(struct inode
*inode
, struct file
*filp
)
2979 long cpu_file
= (long) inode
->i_private
;
2980 struct trace_iterator
*iter
;
2983 if (tracing_disabled
)
2986 mutex_lock(&trace_types_lock
);
2988 /* create a buffer to store the information to pass to userspace */
2989 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2996 * We make a copy of the current tracer to avoid concurrent
2997 * changes on it while we are reading.
2999 iter
->trace
= kmalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
3005 *iter
->trace
= *current_trace
;
3007 if (!alloc_cpumask_var(&iter
->started
, GFP_KERNEL
)) {
3012 /* trace pipe does not show start of buffer */
3013 cpumask_setall(iter
->started
);
3015 if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
3016 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
3018 iter
->cpu_file
= cpu_file
;
3019 iter
->tr
= &global_trace
;
3020 mutex_init(&iter
->mutex
);
3021 filp
->private_data
= iter
;
3023 if (iter
->trace
->pipe_open
)
3024 iter
->trace
->pipe_open(iter
);
3026 nonseekable_open(inode
, filp
);
3028 mutex_unlock(&trace_types_lock
);
3034 mutex_unlock(&trace_types_lock
);
3038 static int tracing_release_pipe(struct inode
*inode
, struct file
*file
)
3040 struct trace_iterator
*iter
= file
->private_data
;
3042 mutex_lock(&trace_types_lock
);
3044 if (iter
->trace
->pipe_close
)
3045 iter
->trace
->pipe_close(iter
);
3047 mutex_unlock(&trace_types_lock
);
3049 free_cpumask_var(iter
->started
);
3050 mutex_destroy(&iter
->mutex
);
3058 tracing_poll_pipe(struct file
*filp
, poll_table
*poll_table
)
3060 struct trace_iterator
*iter
= filp
->private_data
;
3062 if (trace_flags
& TRACE_ITER_BLOCK
) {
3064 * Always select as readable when in blocking mode
3066 return POLLIN
| POLLRDNORM
;
3068 if (!trace_empty(iter
))
3069 return POLLIN
| POLLRDNORM
;
3070 poll_wait(filp
, &trace_wait
, poll_table
);
3071 if (!trace_empty(iter
))
3072 return POLLIN
| POLLRDNORM
;
3079 void default_wait_pipe(struct trace_iterator
*iter
)
3083 prepare_to_wait(&trace_wait
, &wait
, TASK_INTERRUPTIBLE
);
3085 if (trace_empty(iter
))
3088 finish_wait(&trace_wait
, &wait
);
3092 * This is a make-shift waitqueue.
3093 * A tracer might use this callback on some rare cases:
3095 * 1) the current tracer might hold the runqueue lock when it wakes up
3096 * a reader, hence a deadlock (sched, function, and function graph tracers)
3097 * 2) the function tracers, trace all functions, we don't want
3098 * the overhead of calling wake_up and friends
3099 * (and tracing them too)
3101 * Anyway, this is really very primitive wakeup.
3103 void poll_wait_pipe(struct trace_iterator
*iter
)
3105 set_current_state(TASK_INTERRUPTIBLE
);
3106 /* sleep for 100 msecs, and try again. */
3107 schedule_timeout(HZ
/ 10);
3110 /* Must be called with trace_types_lock mutex held. */
3111 static int tracing_wait_pipe(struct file
*filp
)
3113 struct trace_iterator
*iter
= filp
->private_data
;
3115 while (trace_empty(iter
)) {
3117 if ((filp
->f_flags
& O_NONBLOCK
)) {
3121 mutex_unlock(&iter
->mutex
);
3123 iter
->trace
->wait_pipe(iter
);
3125 mutex_lock(&iter
->mutex
);
3127 if (signal_pending(current
))
3131 * We block until we read something and tracing is disabled.
3132 * We still block if tracing is disabled, but we have never
3133 * read anything. This allows a user to cat this file, and
3134 * then enable tracing. But after we have read something,
3135 * we give an EOF when tracing is again disabled.
3137 * iter->pos will be 0 if we haven't read anything.
3139 if (!tracer_enabled
&& iter
->pos
)
3150 tracing_read_pipe(struct file
*filp
, char __user
*ubuf
,
3151 size_t cnt
, loff_t
*ppos
)
3153 struct trace_iterator
*iter
= filp
->private_data
;
3154 static struct tracer
*old_tracer
;
3157 /* return any leftover data */
3158 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
3162 trace_seq_init(&iter
->seq
);
3164 /* copy the tracer to avoid using a global lock all around */
3165 mutex_lock(&trace_types_lock
);
3166 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
3167 old_tracer
= current_trace
;
3168 *iter
->trace
= *current_trace
;
3170 mutex_unlock(&trace_types_lock
);
3173 * Avoid more than one consumer on a single file descriptor
3174 * This is just a matter of traces coherency, the ring buffer itself
3177 mutex_lock(&iter
->mutex
);
3178 if (iter
->trace
->read
) {
3179 sret
= iter
->trace
->read(iter
, filp
, ubuf
, cnt
, ppos
);
3185 sret
= tracing_wait_pipe(filp
);
3189 /* stop when tracing is finished */
3190 if (trace_empty(iter
)) {
3195 if (cnt
>= PAGE_SIZE
)
3196 cnt
= PAGE_SIZE
- 1;
3198 /* reset all but tr, trace, and overruns */
3199 memset(&iter
->seq
, 0,
3200 sizeof(struct trace_iterator
) -
3201 offsetof(struct trace_iterator
, seq
));
3204 trace_event_read_lock();
3205 trace_access_lock(iter
->cpu_file
);
3206 while (trace_find_next_entry_inc(iter
) != NULL
) {
3207 enum print_line_t ret
;
3208 int len
= iter
->seq
.len
;
3210 ret
= print_trace_line(iter
);
3211 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
3212 /* don't print partial lines */
3213 iter
->seq
.len
= len
;
3216 if (ret
!= TRACE_TYPE_NO_CONSUME
)
3217 trace_consume(iter
);
3219 if (iter
->seq
.len
>= cnt
)
3222 trace_access_unlock(iter
->cpu_file
);
3223 trace_event_read_unlock();
3225 /* Now copy what we have to the user */
3226 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
3227 if (iter
->seq
.readpos
>= iter
->seq
.len
)
3228 trace_seq_init(&iter
->seq
);
3231 * If there was nothing to send to user, inspite of consuming trace
3232 * entries, go back to wait for more entries.
3238 mutex_unlock(&iter
->mutex
);
3243 static void tracing_pipe_buf_release(struct pipe_inode_info
*pipe
,
3244 struct pipe_buffer
*buf
)
3246 __free_page(buf
->page
);
3249 static void tracing_spd_release_pipe(struct splice_pipe_desc
*spd
,
3252 __free_page(spd
->pages
[idx
]);
3255 static const struct pipe_buf_operations tracing_pipe_buf_ops
= {
3257 .map
= generic_pipe_buf_map
,
3258 .unmap
= generic_pipe_buf_unmap
,
3259 .confirm
= generic_pipe_buf_confirm
,
3260 .release
= tracing_pipe_buf_release
,
3261 .steal
= generic_pipe_buf_steal
,
3262 .get
= generic_pipe_buf_get
,
3266 tracing_fill_pipe_page(size_t rem
, struct trace_iterator
*iter
)
3271 /* Seq buffer is page-sized, exactly what we need. */
3273 count
= iter
->seq
.len
;
3274 ret
= print_trace_line(iter
);
3275 count
= iter
->seq
.len
- count
;
3278 iter
->seq
.len
-= count
;
3281 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
3282 iter
->seq
.len
-= count
;
3286 if (ret
!= TRACE_TYPE_NO_CONSUME
)
3287 trace_consume(iter
);
3289 if (!trace_find_next_entry_inc(iter
)) {
3299 static ssize_t
tracing_splice_read_pipe(struct file
*filp
,
3301 struct pipe_inode_info
*pipe
,
3305 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
3306 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
3307 struct trace_iterator
*iter
= filp
->private_data
;
3308 struct splice_pipe_desc spd
= {
3310 .partial
= partial_def
,
3311 .nr_pages
= 0, /* This gets updated below. */
3313 .ops
= &tracing_pipe_buf_ops
,
3314 .spd_release
= tracing_spd_release_pipe
,
3316 static struct tracer
*old_tracer
;
3321 if (splice_grow_spd(pipe
, &spd
))
3324 /* copy the tracer to avoid using a global lock all around */
3325 mutex_lock(&trace_types_lock
);
3326 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
3327 old_tracer
= current_trace
;
3328 *iter
->trace
= *current_trace
;
3330 mutex_unlock(&trace_types_lock
);
3332 mutex_lock(&iter
->mutex
);
3334 if (iter
->trace
->splice_read
) {
3335 ret
= iter
->trace
->splice_read(iter
, filp
,
3336 ppos
, pipe
, len
, flags
);
3341 ret
= tracing_wait_pipe(filp
);
3345 if (!iter
->ent
&& !trace_find_next_entry_inc(iter
)) {
3350 trace_event_read_lock();
3351 trace_access_lock(iter
->cpu_file
);
3353 /* Fill as many pages as possible. */
3354 for (i
= 0, rem
= len
; i
< pipe
->buffers
&& rem
; i
++) {
3355 spd
.pages
[i
] = alloc_page(GFP_KERNEL
);
3359 rem
= tracing_fill_pipe_page(rem
, iter
);
3361 /* Copy the data into the page, so we can start over. */
3362 ret
= trace_seq_to_buffer(&iter
->seq
,
3363 page_address(spd
.pages
[i
]),
3366 __free_page(spd
.pages
[i
]);
3369 spd
.partial
[i
].offset
= 0;
3370 spd
.partial
[i
].len
= iter
->seq
.len
;
3372 trace_seq_init(&iter
->seq
);
3375 trace_access_unlock(iter
->cpu_file
);
3376 trace_event_read_unlock();
3377 mutex_unlock(&iter
->mutex
);
3381 ret
= splice_to_pipe(pipe
, &spd
);
3383 splice_shrink_spd(pipe
, &spd
);
3387 mutex_unlock(&iter
->mutex
);
3392 tracing_entries_read(struct file
*filp
, char __user
*ubuf
,
3393 size_t cnt
, loff_t
*ppos
)
3395 struct trace_array
*tr
= filp
->private_data
;
3399 mutex_lock(&trace_types_lock
);
3400 if (!ring_buffer_expanded
)
3401 r
= sprintf(buf
, "%lu (expanded: %lu)\n",
3403 trace_buf_size
>> 10);
3405 r
= sprintf(buf
, "%lu\n", tr
->entries
>> 10);
3406 mutex_unlock(&trace_types_lock
);
3408 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3412 tracing_entries_write(struct file
*filp
, const char __user
*ubuf
,
3413 size_t cnt
, loff_t
*ppos
)
3419 if (cnt
>= sizeof(buf
))
3422 if (copy_from_user(&buf
, ubuf
, cnt
))
3427 ret
= strict_strtoul(buf
, 10, &val
);
3431 /* must have at least 1 entry */
3435 mutex_lock(&trace_types_lock
);
3439 /* disable all cpu buffers */
3440 for_each_tracing_cpu(cpu
) {
3441 if (global_trace
.data
[cpu
])
3442 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
3443 if (max_tr
.data
[cpu
])
3444 atomic_inc(&max_tr
.data
[cpu
]->disabled
);
3447 /* value is in KB */
3450 if (val
!= global_trace
.entries
) {
3451 ret
= tracing_resize_ring_buffer(val
);
3460 /* If check pages failed, return ENOMEM */
3461 if (tracing_disabled
)
3464 for_each_tracing_cpu(cpu
) {
3465 if (global_trace
.data
[cpu
])
3466 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
3467 if (max_tr
.data
[cpu
])
3468 atomic_dec(&max_tr
.data
[cpu
]->disabled
);
3472 mutex_unlock(&trace_types_lock
);
3477 static int mark_printk(const char *fmt
, ...)
3481 va_start(args
, fmt
);
3482 ret
= trace_vprintk(0, fmt
, args
);
3488 tracing_mark_write(struct file
*filp
, const char __user
*ubuf
,
3489 size_t cnt
, loff_t
*fpos
)
3494 if (tracing_disabled
)
3497 if (cnt
> TRACE_BUF_SIZE
)
3498 cnt
= TRACE_BUF_SIZE
;
3500 buf
= kmalloc(cnt
+ 2, GFP_KERNEL
);
3504 if (copy_from_user(buf
, ubuf
, cnt
)) {
3508 if (buf
[cnt
-1] != '\n') {
3514 written
= mark_printk("%s", buf
);
3518 /* don't tell userspace we wrote more - it might confuse them */
3525 static int tracing_clock_show(struct seq_file
*m
, void *v
)
3529 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++)
3531 "%s%s%s%s", i
? " " : "",
3532 i
== trace_clock_id
? "[" : "", trace_clocks
[i
].name
,
3533 i
== trace_clock_id
? "]" : "");
3539 static ssize_t
tracing_clock_write(struct file
*filp
, const char __user
*ubuf
,
3540 size_t cnt
, loff_t
*fpos
)
3543 const char *clockstr
;
3546 if (cnt
>= sizeof(buf
))
3549 if (copy_from_user(&buf
, ubuf
, cnt
))
3554 clockstr
= strstrip(buf
);
3556 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++) {
3557 if (strcmp(trace_clocks
[i
].name
, clockstr
) == 0)
3560 if (i
== ARRAY_SIZE(trace_clocks
))
3565 mutex_lock(&trace_types_lock
);
3567 ring_buffer_set_clock(global_trace
.buffer
, trace_clocks
[i
].func
);
3569 ring_buffer_set_clock(max_tr
.buffer
, trace_clocks
[i
].func
);
3571 mutex_unlock(&trace_types_lock
);
3578 static int tracing_clock_open(struct inode
*inode
, struct file
*file
)
3580 if (tracing_disabled
)
3582 return single_open(file
, tracing_clock_show
, NULL
);
3585 static const struct file_operations tracing_max_lat_fops
= {
3586 .open
= tracing_open_generic
,
3587 .read
= tracing_max_lat_read
,
3588 .write
= tracing_max_lat_write
,
3589 .llseek
= generic_file_llseek
,
3592 static const struct file_operations tracing_ctrl_fops
= {
3593 .open
= tracing_open_generic
,
3594 .read
= tracing_ctrl_read
,
3595 .write
= tracing_ctrl_write
,
3596 .llseek
= generic_file_llseek
,
3599 static const struct file_operations set_tracer_fops
= {
3600 .open
= tracing_open_generic
,
3601 .read
= tracing_set_trace_read
,
3602 .write
= tracing_set_trace_write
,
3603 .llseek
= generic_file_llseek
,
3606 static const struct file_operations tracing_pipe_fops
= {
3607 .open
= tracing_open_pipe
,
3608 .poll
= tracing_poll_pipe
,
3609 .read
= tracing_read_pipe
,
3610 .splice_read
= tracing_splice_read_pipe
,
3611 .release
= tracing_release_pipe
,
3612 .llseek
= no_llseek
,
3615 static const struct file_operations tracing_entries_fops
= {
3616 .open
= tracing_open_generic
,
3617 .read
= tracing_entries_read
,
3618 .write
= tracing_entries_write
,
3619 .llseek
= generic_file_llseek
,
3622 static const struct file_operations tracing_mark_fops
= {
3623 .open
= tracing_open_generic
,
3624 .write
= tracing_mark_write
,
3625 .llseek
= generic_file_llseek
,
3628 static const struct file_operations trace_clock_fops
= {
3629 .open
= tracing_clock_open
,
3631 .llseek
= seq_lseek
,
3632 .release
= single_release
,
3633 .write
= tracing_clock_write
,
3636 struct ftrace_buffer_info
{
3637 struct trace_array
*tr
;
3643 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
)
3645 int cpu
= (int)(long)inode
->i_private
;
3646 struct ftrace_buffer_info
*info
;
3648 if (tracing_disabled
)
3651 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
3655 info
->tr
= &global_trace
;
3658 /* Force reading ring buffer for first read */
3659 info
->read
= (unsigned int)-1;
3661 filp
->private_data
= info
;
3663 return nonseekable_open(inode
, filp
);
3667 tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
3668 size_t count
, loff_t
*ppos
)
3670 struct ftrace_buffer_info
*info
= filp
->private_data
;
3678 info
->spare
= ring_buffer_alloc_read_page(info
->tr
->buffer
);
3682 /* Do we have previous read data to read? */
3683 if (info
->read
< PAGE_SIZE
)
3688 trace_access_lock(info
->cpu
);
3689 ret
= ring_buffer_read_page(info
->tr
->buffer
,
3693 trace_access_unlock(info
->cpu
);
3698 size
= PAGE_SIZE
- info
->read
;
3702 ret
= copy_to_user(ubuf
, info
->spare
+ info
->read
, size
);
3713 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
)
3715 struct ftrace_buffer_info
*info
= file
->private_data
;
3718 ring_buffer_free_read_page(info
->tr
->buffer
, info
->spare
);
3725 struct ring_buffer
*buffer
;
3730 static void buffer_pipe_buf_release(struct pipe_inode_info
*pipe
,
3731 struct pipe_buffer
*buf
)
3733 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
3738 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
3743 static int buffer_pipe_buf_steal(struct pipe_inode_info
*pipe
,
3744 struct pipe_buffer
*buf
)
3749 static void buffer_pipe_buf_get(struct pipe_inode_info
*pipe
,
3750 struct pipe_buffer
*buf
)
3752 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
3757 /* Pipe buffer operations for a buffer. */
3758 static const struct pipe_buf_operations buffer_pipe_buf_ops
= {
3760 .map
= generic_pipe_buf_map
,
3761 .unmap
= generic_pipe_buf_unmap
,
3762 .confirm
= generic_pipe_buf_confirm
,
3763 .release
= buffer_pipe_buf_release
,
3764 .steal
= buffer_pipe_buf_steal
,
3765 .get
= buffer_pipe_buf_get
,
3769 * Callback from splice_to_pipe(), if we need to release some pages
3770 * at the end of the spd in case we error'ed out in filling the pipe.
3772 static void buffer_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
3774 struct buffer_ref
*ref
=
3775 (struct buffer_ref
*)spd
->partial
[i
].private;
3780 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
3782 spd
->partial
[i
].private = 0;
3786 tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
3787 struct pipe_inode_info
*pipe
, size_t len
,
3790 struct ftrace_buffer_info
*info
= file
->private_data
;
3791 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
3792 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
3793 struct splice_pipe_desc spd
= {
3795 .partial
= partial_def
,
3797 .ops
= &buffer_pipe_buf_ops
,
3798 .spd_release
= buffer_spd_release
,
3800 struct buffer_ref
*ref
;
3801 int entries
, size
, i
;
3804 if (splice_grow_spd(pipe
, &spd
))
3807 if (*ppos
& (PAGE_SIZE
- 1)) {
3808 WARN_ONCE(1, "Ftrace: previous read must page-align\n");
3813 if (len
& (PAGE_SIZE
- 1)) {
3814 WARN_ONCE(1, "Ftrace: splice_read should page-align\n");
3815 if (len
< PAGE_SIZE
) {
3822 trace_access_lock(info
->cpu
);
3823 entries
= ring_buffer_entries_cpu(info
->tr
->buffer
, info
->cpu
);
3825 for (i
= 0; i
< pipe
->buffers
&& len
&& entries
; i
++, len
-= PAGE_SIZE
) {
3829 ref
= kzalloc(sizeof(*ref
), GFP_KERNEL
);
3834 ref
->buffer
= info
->tr
->buffer
;
3835 ref
->page
= ring_buffer_alloc_read_page(ref
->buffer
);
3841 r
= ring_buffer_read_page(ref
->buffer
, &ref
->page
,
3844 ring_buffer_free_read_page(ref
->buffer
,
3851 * zero out any left over data, this is going to
3854 size
= ring_buffer_page_len(ref
->page
);
3855 if (size
< PAGE_SIZE
)
3856 memset(ref
->page
+ size
, 0, PAGE_SIZE
- size
);
3858 page
= virt_to_page(ref
->page
);
3860 spd
.pages
[i
] = page
;
3861 spd
.partial
[i
].len
= PAGE_SIZE
;
3862 spd
.partial
[i
].offset
= 0;
3863 spd
.partial
[i
].private = (unsigned long)ref
;
3867 entries
= ring_buffer_entries_cpu(info
->tr
->buffer
, info
->cpu
);
3870 trace_access_unlock(info
->cpu
);
3873 /* did we read anything? */
3874 if (!spd
.nr_pages
) {
3875 if (flags
& SPLICE_F_NONBLOCK
)
3883 ret
= splice_to_pipe(pipe
, &spd
);
3884 splice_shrink_spd(pipe
, &spd
);
3889 static const struct file_operations tracing_buffers_fops
= {
3890 .open
= tracing_buffers_open
,
3891 .read
= tracing_buffers_read
,
3892 .release
= tracing_buffers_release
,
3893 .splice_read
= tracing_buffers_splice_read
,
3894 .llseek
= no_llseek
,
3898 tracing_stats_read(struct file
*filp
, char __user
*ubuf
,
3899 size_t count
, loff_t
*ppos
)
3901 unsigned long cpu
= (unsigned long)filp
->private_data
;
3902 struct trace_array
*tr
= &global_trace
;
3903 struct trace_seq
*s
;
3906 s
= kmalloc(sizeof(*s
), GFP_KERNEL
);
3912 cnt
= ring_buffer_entries_cpu(tr
->buffer
, cpu
);
3913 trace_seq_printf(s
, "entries: %ld\n", cnt
);
3915 cnt
= ring_buffer_overrun_cpu(tr
->buffer
, cpu
);
3916 trace_seq_printf(s
, "overrun: %ld\n", cnt
);
3918 cnt
= ring_buffer_commit_overrun_cpu(tr
->buffer
, cpu
);
3919 trace_seq_printf(s
, "commit overrun: %ld\n", cnt
);
3921 count
= simple_read_from_buffer(ubuf
, count
, ppos
, s
->buffer
, s
->len
);
3928 static const struct file_operations tracing_stats_fops
= {
3929 .open
= tracing_open_generic
,
3930 .read
= tracing_stats_read
,
3931 .llseek
= generic_file_llseek
,
3934 #ifdef CONFIG_DYNAMIC_FTRACE
3936 int __weak
ftrace_arch_read_dyn_info(char *buf
, int size
)
3942 tracing_read_dyn_info(struct file
*filp
, char __user
*ubuf
,
3943 size_t cnt
, loff_t
*ppos
)
3945 static char ftrace_dyn_info_buffer
[1024];
3946 static DEFINE_MUTEX(dyn_info_mutex
);
3947 unsigned long *p
= filp
->private_data
;
3948 char *buf
= ftrace_dyn_info_buffer
;
3949 int size
= ARRAY_SIZE(ftrace_dyn_info_buffer
);
3952 mutex_lock(&dyn_info_mutex
);
3953 r
= sprintf(buf
, "%ld ", *p
);
3955 r
+= ftrace_arch_read_dyn_info(buf
+r
, (size
-1)-r
);
3958 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3960 mutex_unlock(&dyn_info_mutex
);
3965 static const struct file_operations tracing_dyn_info_fops
= {
3966 .open
= tracing_open_generic
,
3967 .read
= tracing_read_dyn_info
,
3968 .llseek
= generic_file_llseek
,
3972 static struct dentry
*d_tracer
;
3974 struct dentry
*tracing_init_dentry(void)
3981 if (!debugfs_initialized())
3984 d_tracer
= debugfs_create_dir("tracing", NULL
);
3986 if (!d_tracer
&& !once
) {
3988 pr_warning("Could not create debugfs directory 'tracing'\n");
3995 static struct dentry
*d_percpu
;
3997 struct dentry
*tracing_dentry_percpu(void)
4000 struct dentry
*d_tracer
;
4005 d_tracer
= tracing_init_dentry();
4010 d_percpu
= debugfs_create_dir("per_cpu", d_tracer
);
4012 if (!d_percpu
&& !once
) {
4014 pr_warning("Could not create debugfs directory 'per_cpu'\n");
4021 static void tracing_init_debugfs_percpu(long cpu
)
4023 struct dentry
*d_percpu
= tracing_dentry_percpu();
4024 struct dentry
*d_cpu
;
4025 char cpu_dir
[30]; /* 30 characters should be more than enough */
4027 snprintf(cpu_dir
, 30, "cpu%ld", cpu
);
4028 d_cpu
= debugfs_create_dir(cpu_dir
, d_percpu
);
4030 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir
);
4034 /* per cpu trace_pipe */
4035 trace_create_file("trace_pipe", 0444, d_cpu
,
4036 (void *) cpu
, &tracing_pipe_fops
);
4039 trace_create_file("trace", 0644, d_cpu
,
4040 (void *) cpu
, &tracing_fops
);
4042 trace_create_file("trace_pipe_raw", 0444, d_cpu
,
4043 (void *) cpu
, &tracing_buffers_fops
);
4045 trace_create_file("stats", 0444, d_cpu
,
4046 (void *) cpu
, &tracing_stats_fops
);
4049 #ifdef CONFIG_FTRACE_SELFTEST
4050 /* Let selftest have access to static functions in this file */
4051 #include "trace_selftest.c"
4054 struct trace_option_dentry
{
4055 struct tracer_opt
*opt
;
4056 struct tracer_flags
*flags
;
4057 struct dentry
*entry
;
4061 trace_options_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
4064 struct trace_option_dentry
*topt
= filp
->private_data
;
4067 if (topt
->flags
->val
& topt
->opt
->bit
)
4072 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
4076 trace_options_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
4079 struct trace_option_dentry
*topt
= filp
->private_data
;
4084 if (cnt
>= sizeof(buf
))
4087 if (copy_from_user(&buf
, ubuf
, cnt
))
4092 ret
= strict_strtoul(buf
, 10, &val
);
4096 if (val
!= 0 && val
!= 1)
4099 if (!!(topt
->flags
->val
& topt
->opt
->bit
) != val
) {
4100 mutex_lock(&trace_types_lock
);
4101 ret
= __set_tracer_option(current_trace
, topt
->flags
,
4103 mutex_unlock(&trace_types_lock
);
4114 static const struct file_operations trace_options_fops
= {
4115 .open
= tracing_open_generic
,
4116 .read
= trace_options_read
,
4117 .write
= trace_options_write
,
4118 .llseek
= generic_file_llseek
,
4122 trace_options_core_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
4125 long index
= (long)filp
->private_data
;
4128 if (trace_flags
& (1 << index
))
4133 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
4137 trace_options_core_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
4140 long index
= (long)filp
->private_data
;
4145 if (cnt
>= sizeof(buf
))
4148 if (copy_from_user(&buf
, ubuf
, cnt
))
4153 ret
= strict_strtoul(buf
, 10, &val
);
4157 if (val
!= 0 && val
!= 1)
4159 set_tracer_flags(1 << index
, val
);
4166 static const struct file_operations trace_options_core_fops
= {
4167 .open
= tracing_open_generic
,
4168 .read
= trace_options_core_read
,
4169 .write
= trace_options_core_write
,
4170 .llseek
= generic_file_llseek
,
4173 struct dentry
*trace_create_file(const char *name
,
4175 struct dentry
*parent
,
4177 const struct file_operations
*fops
)
4181 ret
= debugfs_create_file(name
, mode
, parent
, data
, fops
);
4183 pr_warning("Could not create debugfs '%s' entry\n", name
);
4189 static struct dentry
*trace_options_init_dentry(void)
4191 struct dentry
*d_tracer
;
4192 static struct dentry
*t_options
;
4197 d_tracer
= tracing_init_dentry();
4201 t_options
= debugfs_create_dir("options", d_tracer
);
4203 pr_warning("Could not create debugfs directory 'options'\n");
4211 create_trace_option_file(struct trace_option_dentry
*topt
,
4212 struct tracer_flags
*flags
,
4213 struct tracer_opt
*opt
)
4215 struct dentry
*t_options
;
4217 t_options
= trace_options_init_dentry();
4221 topt
->flags
= flags
;
4224 topt
->entry
= trace_create_file(opt
->name
, 0644, t_options
, topt
,
4225 &trace_options_fops
);
4229 static struct trace_option_dentry
*
4230 create_trace_option_files(struct tracer
*tracer
)
4232 struct trace_option_dentry
*topts
;
4233 struct tracer_flags
*flags
;
4234 struct tracer_opt
*opts
;
4240 flags
= tracer
->flags
;
4242 if (!flags
|| !flags
->opts
)
4247 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
4250 topts
= kcalloc(cnt
+ 1, sizeof(*topts
), GFP_KERNEL
);
4254 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
4255 create_trace_option_file(&topts
[cnt
], flags
,
4262 destroy_trace_option_files(struct trace_option_dentry
*topts
)
4269 for (cnt
= 0; topts
[cnt
].opt
; cnt
++) {
4270 if (topts
[cnt
].entry
)
4271 debugfs_remove(topts
[cnt
].entry
);
4277 static struct dentry
*
4278 create_trace_option_core_file(const char *option
, long index
)
4280 struct dentry
*t_options
;
4282 t_options
= trace_options_init_dentry();
4286 return trace_create_file(option
, 0644, t_options
, (void *)index
,
4287 &trace_options_core_fops
);
4290 static __init
void create_trace_options_dir(void)
4292 struct dentry
*t_options
;
4295 t_options
= trace_options_init_dentry();
4299 for (i
= 0; trace_options
[i
]; i
++)
4300 create_trace_option_core_file(trace_options
[i
], i
);
4303 static __init
int tracer_init_debugfs(void)
4305 struct dentry
*d_tracer
;
4308 trace_access_lock_init();
4310 d_tracer
= tracing_init_dentry();
4312 trace_create_file("tracing_enabled", 0644, d_tracer
,
4313 &global_trace
, &tracing_ctrl_fops
);
4315 trace_create_file("trace_options", 0644, d_tracer
,
4316 NULL
, &tracing_iter_fops
);
4318 trace_create_file("tracing_cpumask", 0644, d_tracer
,
4319 NULL
, &tracing_cpumask_fops
);
4321 trace_create_file("trace", 0644, d_tracer
,
4322 (void *) TRACE_PIPE_ALL_CPU
, &tracing_fops
);
4324 trace_create_file("available_tracers", 0444, d_tracer
,
4325 &global_trace
, &show_traces_fops
);
4327 trace_create_file("current_tracer", 0644, d_tracer
,
4328 &global_trace
, &set_tracer_fops
);
4330 #ifdef CONFIG_TRACER_MAX_TRACE
4331 trace_create_file("tracing_max_latency", 0644, d_tracer
,
4332 &tracing_max_latency
, &tracing_max_lat_fops
);
4335 trace_create_file("tracing_thresh", 0644, d_tracer
,
4336 &tracing_thresh
, &tracing_max_lat_fops
);
4338 trace_create_file("README", 0444, d_tracer
,
4339 NULL
, &tracing_readme_fops
);
4341 trace_create_file("trace_pipe", 0444, d_tracer
,
4342 (void *) TRACE_PIPE_ALL_CPU
, &tracing_pipe_fops
);
4344 trace_create_file("buffer_size_kb", 0644, d_tracer
,
4345 &global_trace
, &tracing_entries_fops
);
4347 trace_create_file("trace_marker", 0220, d_tracer
,
4348 NULL
, &tracing_mark_fops
);
4350 trace_create_file("saved_cmdlines", 0444, d_tracer
,
4351 NULL
, &tracing_saved_cmdlines_fops
);
4353 trace_create_file("trace_clock", 0644, d_tracer
, NULL
,
4356 #ifdef CONFIG_DYNAMIC_FTRACE
4357 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
4358 &ftrace_update_tot_cnt
, &tracing_dyn_info_fops
);
4361 create_trace_options_dir();
4363 for_each_tracing_cpu(cpu
)
4364 tracing_init_debugfs_percpu(cpu
);
4369 static int trace_panic_handler(struct notifier_block
*this,
4370 unsigned long event
, void *unused
)
4372 if (ftrace_dump_on_oops
)
4373 ftrace_dump(ftrace_dump_on_oops
);
4377 static struct notifier_block trace_panic_notifier
= {
4378 .notifier_call
= trace_panic_handler
,
4380 .priority
= 150 /* priority: INT_MAX >= x >= 0 */
4383 static int trace_die_handler(struct notifier_block
*self
,
4389 if (ftrace_dump_on_oops
)
4390 ftrace_dump(ftrace_dump_on_oops
);
4398 static struct notifier_block trace_die_notifier
= {
4399 .notifier_call
= trace_die_handler
,
4404 * printk is set to max of 1024, we really don't need it that big.
4405 * Nothing should be printing 1000 characters anyway.
4407 #define TRACE_MAX_PRINT 1000
4410 * Define here KERN_TRACE so that we have one place to modify
4411 * it if we decide to change what log level the ftrace dump
4414 #define KERN_TRACE KERN_EMERG
4417 trace_printk_seq(struct trace_seq
*s
)
4419 /* Probably should print a warning here. */
4423 /* should be zero ended, but we are paranoid. */
4424 s
->buffer
[s
->len
] = 0;
4426 printk(KERN_TRACE
"%s", s
->buffer
);
4431 void trace_init_global_iter(struct trace_iterator
*iter
)
4433 iter
->tr
= &global_trace
;
4434 iter
->trace
= current_trace
;
4435 iter
->cpu_file
= TRACE_PIPE_ALL_CPU
;
4439 __ftrace_dump(bool disable_tracing
, enum ftrace_dump_mode oops_dump_mode
)
4441 static arch_spinlock_t ftrace_dump_lock
=
4442 (arch_spinlock_t
)__ARCH_SPIN_LOCK_UNLOCKED
;
4443 /* use static because iter can be a bit big for the stack */
4444 static struct trace_iterator iter
;
4445 unsigned int old_userobj
;
4446 static int dump_ran
;
4447 unsigned long flags
;
4451 local_irq_save(flags
);
4452 arch_spin_lock(&ftrace_dump_lock
);
4460 if (disable_tracing
)
4463 trace_init_global_iter(&iter
);
4465 for_each_tracing_cpu(cpu
) {
4466 atomic_inc(&iter
.tr
->data
[cpu
]->disabled
);
4469 old_userobj
= trace_flags
& TRACE_ITER_SYM_USEROBJ
;
4471 /* don't look at user memory in panic mode */
4472 trace_flags
&= ~TRACE_ITER_SYM_USEROBJ
;
4474 /* Simulate the iterator */
4475 iter
.tr
= &global_trace
;
4476 iter
.trace
= current_trace
;
4478 switch (oops_dump_mode
) {
4480 iter
.cpu_file
= TRACE_PIPE_ALL_CPU
;
4483 iter
.cpu_file
= raw_smp_processor_id();
4488 printk(KERN_TRACE
"Bad dumping mode, switching to all CPUs dump\n");
4489 iter
.cpu_file
= TRACE_PIPE_ALL_CPU
;
4492 printk(KERN_TRACE
"Dumping ftrace buffer:\n");
4495 * We need to stop all tracing on all CPUS to read the
4496 * the next buffer. This is a bit expensive, but is
4497 * not done often. We fill all what we can read,
4498 * and then release the locks again.
4501 while (!trace_empty(&iter
)) {
4504 printk(KERN_TRACE
"---------------------------------\n");
4508 /* reset all but tr, trace, and overruns */
4509 memset(&iter
.seq
, 0,
4510 sizeof(struct trace_iterator
) -
4511 offsetof(struct trace_iterator
, seq
));
4512 iter
.iter_flags
|= TRACE_FILE_LAT_FMT
;
4515 if (trace_find_next_entry_inc(&iter
) != NULL
) {
4518 ret
= print_trace_line(&iter
);
4519 if (ret
!= TRACE_TYPE_NO_CONSUME
)
4520 trace_consume(&iter
);
4523 trace_printk_seq(&iter
.seq
);
4527 printk(KERN_TRACE
" (ftrace buffer empty)\n");
4529 printk(KERN_TRACE
"---------------------------------\n");
4532 /* Re-enable tracing if requested */
4533 if (!disable_tracing
) {
4534 trace_flags
|= old_userobj
;
4536 for_each_tracing_cpu(cpu
) {
4537 atomic_dec(&iter
.tr
->data
[cpu
]->disabled
);
4543 arch_spin_unlock(&ftrace_dump_lock
);
4544 local_irq_restore(flags
);
4547 /* By default: disable tracing after the dump */
4548 void ftrace_dump(enum ftrace_dump_mode oops_dump_mode
)
4550 __ftrace_dump(true, oops_dump_mode
);
4553 __init
static int tracer_alloc_buffers(void)
4559 if (!alloc_cpumask_var(&tracing_buffer_mask
, GFP_KERNEL
))
4562 if (!alloc_cpumask_var(&tracing_cpumask
, GFP_KERNEL
))
4563 goto out_free_buffer_mask
;
4565 /* To save memory, keep the ring buffer size to its minimum */
4566 if (ring_buffer_expanded
)
4567 ring_buf_size
= trace_buf_size
;
4571 cpumask_copy(tracing_buffer_mask
, cpu_possible_mask
);
4572 cpumask_copy(tracing_cpumask
, cpu_all_mask
);
4574 /* TODO: make the number of buffers hot pluggable with CPUS */
4575 global_trace
.buffer
= ring_buffer_alloc(ring_buf_size
,
4576 TRACE_BUFFER_FLAGS
);
4577 if (!global_trace
.buffer
) {
4578 printk(KERN_ERR
"tracer: failed to allocate ring buffer!\n");
4580 goto out_free_cpumask
;
4582 global_trace
.entries
= ring_buffer_size(global_trace
.buffer
);
4585 #ifdef CONFIG_TRACER_MAX_TRACE
4586 max_tr
.buffer
= ring_buffer_alloc(1, TRACE_BUFFER_FLAGS
);
4587 if (!max_tr
.buffer
) {
4588 printk(KERN_ERR
"tracer: failed to allocate max ring buffer!\n");
4590 ring_buffer_free(global_trace
.buffer
);
4591 goto out_free_cpumask
;
4596 /* Allocate the first page for all buffers */
4597 for_each_tracing_cpu(i
) {
4598 global_trace
.data
[i
] = &per_cpu(global_trace_cpu
, i
);
4599 max_tr
.data
[i
] = &per_cpu(max_tr_data
, i
);
4602 trace_init_cmdlines();
4604 register_tracer(&nop_trace
);
4605 current_trace
= &nop_trace
;
4606 /* All seems OK, enable tracing */
4607 tracing_disabled
= 0;
4609 atomic_notifier_chain_register(&panic_notifier_list
,
4610 &trace_panic_notifier
);
4612 register_die_notifier(&trace_die_notifier
);
4617 free_cpumask_var(tracing_cpumask
);
4618 out_free_buffer_mask
:
4619 free_cpumask_var(tracing_buffer_mask
);
4624 __init
static int clear_boot_tracer(void)
4627 * The default tracer at boot buffer is an init section.
4628 * This function is called in lateinit. If we did not
4629 * find the boot tracer, then clear it out, to prevent
4630 * later registration from accessing the buffer that is
4631 * about to be freed.
4633 if (!default_bootup_tracer
)
4636 printk(KERN_INFO
"ftrace bootup tracer '%s' not registered.\n",
4637 default_bootup_tracer
);
4638 default_bootup_tracer
= NULL
;
4643 early_initcall(tracer_alloc_buffers
);
4644 fs_initcall(tracer_init_debugfs
);
4645 late_initcall(clear_boot_tracer
);