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/smp_lock.h>
21 #include <linux/notifier.h>
22 #include <linux/irqflags.h>
23 #include <linux/debugfs.h>
24 #include <linux/pagemap.h>
25 #include <linux/hardirq.h>
26 #include <linux/linkage.h>
27 #include <linux/uaccess.h>
28 #include <linux/kprobes.h>
29 #include <linux/ftrace.h>
30 #include <linux/module.h>
31 #include <linux/percpu.h>
32 #include <linux/splice.h>
33 #include <linux/kdebug.h>
34 #include <linux/string.h>
35 #include <linux/rwsem.h>
36 #include <linux/slab.h>
37 #include <linux/ctype.h>
38 #include <linux/init.h>
39 #include <linux/poll.h>
43 #include "trace_output.h"
45 #define TRACE_BUFFER_FLAGS (RB_FL_OVERWRITE)
48 * On boot up, the ring buffer is set to the minimum size, so that
49 * we do not waste memory on systems that are not using tracing.
51 int ring_buffer_expanded
;
54 * We need to change this state when a selftest is running.
55 * A selftest will lurk into the ring-buffer to count the
56 * entries inserted during the selftest although some concurrent
57 * insertions into the ring-buffer such as trace_printk could occurred
58 * at the same time, giving false positive or negative results.
60 static bool __read_mostly tracing_selftest_running
;
63 * If a tracer is running, we do not want to run SELFTEST.
65 bool __read_mostly tracing_selftest_disabled
;
67 /* For tracers that don't implement custom flags */
68 static struct tracer_opt dummy_tracer_opt
[] = {
72 static struct tracer_flags dummy_tracer_flags
= {
74 .opts
= dummy_tracer_opt
77 static int dummy_set_flag(u32 old_flags
, u32 bit
, int set
)
83 * Kill all tracing for good (never come back).
84 * It is initialized to 1 but will turn to zero if the initialization
85 * of the tracer is successful. But that is the only place that sets
88 static int tracing_disabled
= 1;
90 DEFINE_PER_CPU(int, ftrace_cpu_disabled
);
92 static inline void ftrace_disable_cpu(void)
95 __this_cpu_inc(ftrace_cpu_disabled
);
98 static inline void ftrace_enable_cpu(void)
100 __this_cpu_dec(ftrace_cpu_disabled
);
104 cpumask_var_t __read_mostly tracing_buffer_mask
;
107 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
109 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
110 * is set, then ftrace_dump is called. This will output the contents
111 * of the ftrace buffers to the console. This is very useful for
112 * capturing traces that lead to crashes and outputing it to a
115 * It is default off, but you can enable it with either specifying
116 * "ftrace_dump_on_oops" in the kernel command line, or setting
117 * /proc/sys/kernel/ftrace_dump_on_oops
118 * Set 1 if you want to dump buffers of all CPUs
119 * Set 2 if you want to dump the buffer of the CPU that triggered oops
122 enum ftrace_dump_mode ftrace_dump_on_oops
;
124 static int tracing_set_tracer(const char *buf
);
126 #define MAX_TRACER_SIZE 100
127 static char bootup_tracer_buf
[MAX_TRACER_SIZE
] __initdata
;
128 static char *default_bootup_tracer
;
130 static int __init
set_cmdline_ftrace(char *str
)
132 strncpy(bootup_tracer_buf
, str
, MAX_TRACER_SIZE
);
133 default_bootup_tracer
= bootup_tracer_buf
;
134 /* We are using ftrace early, expand it */
135 ring_buffer_expanded
= 1;
138 __setup("ftrace=", set_cmdline_ftrace
);
140 static int __init
set_ftrace_dump_on_oops(char *str
)
142 if (*str
++ != '=' || !*str
) {
143 ftrace_dump_on_oops
= DUMP_ALL
;
147 if (!strcmp("orig_cpu", str
)) {
148 ftrace_dump_on_oops
= DUMP_ORIG
;
154 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops
);
156 unsigned long long ns2usecs(cycle_t nsec
)
164 * The global_trace is the descriptor that holds the tracing
165 * buffers for the live tracing. For each CPU, it contains
166 * a link list of pages that will store trace entries. The
167 * page descriptor of the pages in the memory is used to hold
168 * the link list by linking the lru item in the page descriptor
169 * to each of the pages in the buffer per CPU.
171 * For each active CPU there is a data field that holds the
172 * pages for the buffer for that CPU. Each CPU has the same number
173 * of pages allocated for its buffer.
175 static struct trace_array global_trace
;
177 static DEFINE_PER_CPU(struct trace_array_cpu
, global_trace_cpu
);
179 int filter_current_check_discard(struct ring_buffer
*buffer
,
180 struct ftrace_event_call
*call
, void *rec
,
181 struct ring_buffer_event
*event
)
183 return filter_check_discard(call
, rec
, buffer
, event
);
185 EXPORT_SYMBOL_GPL(filter_current_check_discard
);
187 cycle_t
ftrace_now(int cpu
)
191 /* Early boot up does not have a buffer yet */
192 if (!global_trace
.buffer
)
193 return trace_clock_local();
195 ts
= ring_buffer_time_stamp(global_trace
.buffer
, cpu
);
196 ring_buffer_normalize_time_stamp(global_trace
.buffer
, cpu
, &ts
);
202 * The max_tr is used to snapshot the global_trace when a maximum
203 * latency is reached. Some tracers will use this to store a maximum
204 * trace while it continues examining live traces.
206 * The buffers for the max_tr are set up the same as the global_trace.
207 * When a snapshot is taken, the link list of the max_tr is swapped
208 * with the link list of the global_trace and the buffers are reset for
209 * the global_trace so the tracing can continue.
211 static struct trace_array max_tr
;
213 static DEFINE_PER_CPU(struct trace_array_cpu
, max_tr_data
);
215 /* tracer_enabled is used to toggle activation of a tracer */
216 static int tracer_enabled
= 1;
219 * tracing_is_enabled - return tracer_enabled status
221 * This function is used by other tracers to know the status
222 * of the tracer_enabled flag. Tracers may use this function
223 * to know if it should enable their features when starting
224 * up. See irqsoff tracer for an example (start_irqsoff_tracer).
226 int tracing_is_enabled(void)
228 return tracer_enabled
;
232 * trace_buf_size is the size in bytes that is allocated
233 * for a buffer. Note, the number of bytes is always rounded
236 * This number is purposely set to a low number of 16384.
237 * If the dump on oops happens, it will be much appreciated
238 * to not have to wait for all that output. Anyway this can be
239 * boot time and run time configurable.
241 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
243 static unsigned long trace_buf_size
= TRACE_BUF_SIZE_DEFAULT
;
245 /* trace_types holds a link list of available tracers. */
246 static struct tracer
*trace_types __read_mostly
;
248 /* current_trace points to the tracer that is currently active */
249 static struct tracer
*current_trace __read_mostly
;
252 * trace_types_lock is used to protect the trace_types list.
254 static DEFINE_MUTEX(trace_types_lock
);
257 * serialize the access of the ring buffer
259 * ring buffer serializes readers, but it is low level protection.
260 * The validity of the events (which returns by ring_buffer_peek() ..etc)
261 * are not protected by ring buffer.
263 * The content of events may become garbage if we allow other process consumes
264 * these events concurrently:
265 * A) the page of the consumed events may become a normal page
266 * (not reader page) in ring buffer, and this page will be rewrited
267 * by events producer.
268 * B) The page of the consumed events may become a page for splice_read,
269 * and this page will be returned to system.
271 * These primitives allow multi process access to different cpu ring buffer
274 * These primitives don't distinguish read-only and read-consume access.
275 * Multi read-only access are also serialized.
279 static DECLARE_RWSEM(all_cpu_access_lock
);
280 static DEFINE_PER_CPU(struct mutex
, cpu_access_lock
);
282 static inline void trace_access_lock(int cpu
)
284 if (cpu
== TRACE_PIPE_ALL_CPU
) {
285 /* gain it for accessing the whole ring buffer. */
286 down_write(&all_cpu_access_lock
);
288 /* gain it for accessing a cpu ring buffer. */
290 /* Firstly block other trace_access_lock(TRACE_PIPE_ALL_CPU). */
291 down_read(&all_cpu_access_lock
);
293 /* Secondly block other access to this @cpu ring buffer. */
294 mutex_lock(&per_cpu(cpu_access_lock
, cpu
));
298 static inline void trace_access_unlock(int cpu
)
300 if (cpu
== TRACE_PIPE_ALL_CPU
) {
301 up_write(&all_cpu_access_lock
);
303 mutex_unlock(&per_cpu(cpu_access_lock
, cpu
));
304 up_read(&all_cpu_access_lock
);
308 static inline void trace_access_lock_init(void)
312 for_each_possible_cpu(cpu
)
313 mutex_init(&per_cpu(cpu_access_lock
, cpu
));
318 static DEFINE_MUTEX(access_lock
);
320 static inline void trace_access_lock(int cpu
)
323 mutex_lock(&access_lock
);
326 static inline void trace_access_unlock(int cpu
)
329 mutex_unlock(&access_lock
);
332 static inline void trace_access_lock_init(void)
338 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
339 static DECLARE_WAIT_QUEUE_HEAD(trace_wait
);
341 /* trace_flags holds trace_options default values */
342 unsigned long trace_flags
= TRACE_ITER_PRINT_PARENT
| TRACE_ITER_PRINTK
|
343 TRACE_ITER_ANNOTATE
| TRACE_ITER_CONTEXT_INFO
| TRACE_ITER_SLEEP_TIME
|
344 TRACE_ITER_GRAPH_TIME
| TRACE_ITER_RECORD_CMD
;
346 static int trace_stop_count
;
347 static DEFINE_SPINLOCK(tracing_start_lock
);
350 * trace_wake_up - wake up tasks waiting for trace input
352 * Simply wakes up any task that is blocked on the trace_wait
353 * queue. These is used with trace_poll for tasks polling the trace.
355 void trace_wake_up(void)
359 if (trace_flags
& TRACE_ITER_BLOCK
)
362 * The runqueue_is_locked() can fail, but this is the best we
366 if (!runqueue_is_locked(cpu
))
367 wake_up(&trace_wait
);
371 static int __init
set_buf_size(char *str
)
373 unsigned long buf_size
;
377 buf_size
= memparse(str
, &str
);
378 /* nr_entries can not be zero */
381 trace_buf_size
= buf_size
;
384 __setup("trace_buf_size=", set_buf_size
);
386 static int __init
set_tracing_thresh(char *str
)
388 unsigned long threshhold
;
393 ret
= strict_strtoul(str
, 0, &threshhold
);
396 tracing_thresh
= threshhold
* 1000;
399 __setup("tracing_thresh=", set_tracing_thresh
);
401 unsigned long nsecs_to_usecs(unsigned long nsecs
)
406 /* These must match the bit postions in trace_iterator_flags */
407 static const char *trace_options
[] = {
436 { trace_clock_local
, "local" },
437 { trace_clock_global
, "global" },
443 * trace_parser_get_init - gets the buffer for trace parser
445 int trace_parser_get_init(struct trace_parser
*parser
, int size
)
447 memset(parser
, 0, sizeof(*parser
));
449 parser
->buffer
= kmalloc(size
, GFP_KERNEL
);
458 * trace_parser_put - frees the buffer for trace parser
460 void trace_parser_put(struct trace_parser
*parser
)
462 kfree(parser
->buffer
);
466 * trace_get_user - reads the user input string separated by space
467 * (matched by isspace(ch))
469 * For each string found the 'struct trace_parser' is updated,
470 * and the function returns.
472 * Returns number of bytes read.
474 * See kernel/trace/trace.h for 'struct trace_parser' details.
476 int trace_get_user(struct trace_parser
*parser
, const char __user
*ubuf
,
477 size_t cnt
, loff_t
*ppos
)
484 trace_parser_clear(parser
);
486 ret
= get_user(ch
, ubuf
++);
494 * The parser is not finished with the last write,
495 * continue reading the user input without skipping spaces.
498 /* skip white space */
499 while (cnt
&& isspace(ch
)) {
500 ret
= get_user(ch
, ubuf
++);
507 /* only spaces were written */
517 /* read the non-space input */
518 while (cnt
&& !isspace(ch
)) {
519 if (parser
->idx
< parser
->size
- 1)
520 parser
->buffer
[parser
->idx
++] = ch
;
525 ret
= get_user(ch
, ubuf
++);
532 /* We either got finished input or we have to wait for another call. */
534 parser
->buffer
[parser
->idx
] = 0;
535 parser
->cont
= false;
538 parser
->buffer
[parser
->idx
++] = ch
;
548 ssize_t
trace_seq_to_user(struct trace_seq
*s
, char __user
*ubuf
, size_t cnt
)
556 if (s
->len
<= s
->readpos
)
559 len
= s
->len
- s
->readpos
;
562 ret
= copy_to_user(ubuf
, s
->buffer
+ s
->readpos
, cnt
);
572 static ssize_t
trace_seq_to_buffer(struct trace_seq
*s
, void *buf
, size_t cnt
)
577 if (s
->len
<= s
->readpos
)
580 len
= s
->len
- s
->readpos
;
583 ret
= memcpy(buf
, s
->buffer
+ s
->readpos
, cnt
);
592 * ftrace_max_lock is used to protect the swapping of buffers
593 * when taking a max snapshot. The buffers themselves are
594 * protected by per_cpu spinlocks. But the action of the swap
595 * needs its own lock.
597 * This is defined as a arch_spinlock_t in order to help
598 * with performance when lockdep debugging is enabled.
600 * It is also used in other places outside the update_max_tr
601 * so it needs to be defined outside of the
602 * CONFIG_TRACER_MAX_TRACE.
604 static arch_spinlock_t ftrace_max_lock
=
605 (arch_spinlock_t
)__ARCH_SPIN_LOCK_UNLOCKED
;
607 unsigned long __read_mostly tracing_thresh
;
609 #ifdef CONFIG_TRACER_MAX_TRACE
610 unsigned long __read_mostly tracing_max_latency
;
613 * Copy the new maximum trace into the separate maximum-trace
614 * structure. (this way the maximum trace is permanently saved,
615 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
618 __update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
620 struct trace_array_cpu
*data
= tr
->data
[cpu
];
621 struct trace_array_cpu
*max_data
;
624 max_tr
.time_start
= data
->preempt_timestamp
;
626 max_data
= max_tr
.data
[cpu
];
627 max_data
->saved_latency
= tracing_max_latency
;
628 max_data
->critical_start
= data
->critical_start
;
629 max_data
->critical_end
= data
->critical_end
;
631 memcpy(max_data
->comm
, tsk
->comm
, TASK_COMM_LEN
);
632 max_data
->pid
= tsk
->pid
;
633 max_data
->uid
= task_uid(tsk
);
634 max_data
->nice
= tsk
->static_prio
- 20 - MAX_RT_PRIO
;
635 max_data
->policy
= tsk
->policy
;
636 max_data
->rt_priority
= tsk
->rt_priority
;
638 /* record this tasks comm */
639 tracing_record_cmdline(tsk
);
643 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
645 * @tsk: the task with the latency
646 * @cpu: The cpu that initiated the trace.
648 * Flip the buffers between the @tr and the max_tr and record information
649 * about which task was the cause of this latency.
652 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
654 struct ring_buffer
*buf
= tr
->buffer
;
656 if (trace_stop_count
)
659 WARN_ON_ONCE(!irqs_disabled());
660 if (!current_trace
->use_max_tr
) {
664 arch_spin_lock(&ftrace_max_lock
);
666 tr
->buffer
= max_tr
.buffer
;
669 __update_max_tr(tr
, tsk
, cpu
);
670 arch_spin_unlock(&ftrace_max_lock
);
674 * update_max_tr_single - only copy one trace over, and reset the rest
676 * @tsk - task with the latency
677 * @cpu - the cpu of the buffer to copy.
679 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
682 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
686 if (trace_stop_count
)
689 WARN_ON_ONCE(!irqs_disabled());
690 if (!current_trace
->use_max_tr
) {
695 arch_spin_lock(&ftrace_max_lock
);
697 ftrace_disable_cpu();
699 ret
= ring_buffer_swap_cpu(max_tr
.buffer
, tr
->buffer
, cpu
);
703 * We failed to swap the buffer due to a commit taking
704 * place on this CPU. We fail to record, but we reset
705 * the max trace buffer (no one writes directly to it)
706 * and flag that it failed.
708 trace_array_printk(&max_tr
, _THIS_IP_
,
709 "Failed to swap buffers due to commit in progress\n");
714 WARN_ON_ONCE(ret
&& ret
!= -EAGAIN
&& ret
!= -EBUSY
);
716 __update_max_tr(tr
, tsk
, cpu
);
717 arch_spin_unlock(&ftrace_max_lock
);
719 #endif /* CONFIG_TRACER_MAX_TRACE */
722 * register_tracer - register a tracer with the ftrace system.
723 * @type - the plugin for the tracer
725 * Register a new plugin tracer.
727 int register_tracer(struct tracer
*type
)
728 __releases(kernel_lock
)
729 __acquires(kernel_lock
)
735 pr_info("Tracer must have a name\n");
739 if (strlen(type
->name
) >= MAX_TRACER_SIZE
) {
740 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE
);
744 mutex_lock(&trace_types_lock
);
746 tracing_selftest_running
= true;
748 for (t
= trace_types
; t
; t
= t
->next
) {
749 if (strcmp(type
->name
, t
->name
) == 0) {
751 pr_info("Tracer %s already registered\n",
759 type
->set_flag
= &dummy_set_flag
;
761 type
->flags
= &dummy_tracer_flags
;
763 if (!type
->flags
->opts
)
764 type
->flags
->opts
= dummy_tracer_opt
;
765 if (!type
->wait_pipe
)
766 type
->wait_pipe
= default_wait_pipe
;
769 #ifdef CONFIG_FTRACE_STARTUP_TEST
770 if (type
->selftest
&& !tracing_selftest_disabled
) {
771 struct tracer
*saved_tracer
= current_trace
;
772 struct trace_array
*tr
= &global_trace
;
775 * Run a selftest on this tracer.
776 * Here we reset the trace buffer, and set the current
777 * tracer to be this tracer. The tracer can then run some
778 * internal tracing to verify that everything is in order.
779 * If we fail, we do not register this tracer.
781 tracing_reset_online_cpus(tr
);
783 current_trace
= type
;
784 /* the test is responsible for initializing and enabling */
785 pr_info("Testing tracer %s: ", type
->name
);
786 ret
= type
->selftest(type
, tr
);
787 /* the test is responsible for resetting too */
788 current_trace
= saved_tracer
;
790 printk(KERN_CONT
"FAILED!\n");
793 /* Only reset on passing, to avoid touching corrupted buffers */
794 tracing_reset_online_cpus(tr
);
796 printk(KERN_CONT
"PASSED\n");
800 type
->next
= trace_types
;
804 tracing_selftest_running
= false;
805 mutex_unlock(&trace_types_lock
);
807 if (ret
|| !default_bootup_tracer
)
810 if (strncmp(default_bootup_tracer
, type
->name
, MAX_TRACER_SIZE
))
813 printk(KERN_INFO
"Starting tracer '%s'\n", type
->name
);
814 /* Do we want this tracer to start on bootup? */
815 tracing_set_tracer(type
->name
);
816 default_bootup_tracer
= NULL
;
817 /* disable other selftests, since this will break it. */
818 tracing_selftest_disabled
= 1;
819 #ifdef CONFIG_FTRACE_STARTUP_TEST
820 printk(KERN_INFO
"Disabling FTRACE selftests due to running tracer '%s'\n",
828 void unregister_tracer(struct tracer
*type
)
832 mutex_lock(&trace_types_lock
);
833 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
837 pr_info("Tracer %s not registered\n", type
->name
);
843 if (type
== current_trace
&& tracer_enabled
) {
846 if (current_trace
->stop
)
847 current_trace
->stop(&global_trace
);
848 current_trace
= &nop_trace
;
851 mutex_unlock(&trace_types_lock
);
854 static void __tracing_reset(struct ring_buffer
*buffer
, int cpu
)
856 ftrace_disable_cpu();
857 ring_buffer_reset_cpu(buffer
, cpu
);
861 void tracing_reset(struct trace_array
*tr
, int cpu
)
863 struct ring_buffer
*buffer
= tr
->buffer
;
865 ring_buffer_record_disable(buffer
);
867 /* Make sure all commits have finished */
869 __tracing_reset(buffer
, cpu
);
871 ring_buffer_record_enable(buffer
);
874 void tracing_reset_online_cpus(struct trace_array
*tr
)
876 struct ring_buffer
*buffer
= tr
->buffer
;
879 ring_buffer_record_disable(buffer
);
881 /* Make sure all commits have finished */
884 tr
->time_start
= ftrace_now(tr
->cpu
);
886 for_each_online_cpu(cpu
)
887 __tracing_reset(buffer
, cpu
);
889 ring_buffer_record_enable(buffer
);
892 void tracing_reset_current(int cpu
)
894 tracing_reset(&global_trace
, cpu
);
897 void tracing_reset_current_online_cpus(void)
899 tracing_reset_online_cpus(&global_trace
);
902 #define SAVED_CMDLINES 128
903 #define NO_CMDLINE_MAP UINT_MAX
904 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
905 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
906 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
907 static int cmdline_idx
;
908 static arch_spinlock_t trace_cmdline_lock
= __ARCH_SPIN_LOCK_UNLOCKED
;
910 /* temporary disable recording */
911 static atomic_t trace_record_cmdline_disabled __read_mostly
;
913 static void trace_init_cmdlines(void)
915 memset(&map_pid_to_cmdline
, NO_CMDLINE_MAP
, sizeof(map_pid_to_cmdline
));
916 memset(&map_cmdline_to_pid
, NO_CMDLINE_MAP
, sizeof(map_cmdline_to_pid
));
920 int is_tracing_stopped(void)
922 return trace_stop_count
;
926 * ftrace_off_permanent - disable all ftrace code permanently
928 * This should only be called when a serious anomally has
929 * been detected. This will turn off the function tracing,
930 * ring buffers, and other tracing utilites. It takes no
931 * locks and can be called from any context.
933 void ftrace_off_permanent(void)
935 tracing_disabled
= 1;
937 tracing_off_permanent();
941 * tracing_start - quick start of the tracer
943 * If tracing is enabled but was stopped by tracing_stop,
944 * this will start the tracer back up.
946 void tracing_start(void)
948 struct ring_buffer
*buffer
;
951 if (tracing_disabled
)
954 spin_lock_irqsave(&tracing_start_lock
, flags
);
955 if (--trace_stop_count
) {
956 if (trace_stop_count
< 0) {
957 /* Someone screwed up their debugging */
959 trace_stop_count
= 0;
964 /* Prevent the buffers from switching */
965 arch_spin_lock(&ftrace_max_lock
);
967 buffer
= global_trace
.buffer
;
969 ring_buffer_record_enable(buffer
);
971 buffer
= max_tr
.buffer
;
973 ring_buffer_record_enable(buffer
);
975 arch_spin_unlock(&ftrace_max_lock
);
979 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
983 * tracing_stop - quick stop of the tracer
985 * Light weight way to stop tracing. Use in conjunction with
988 void tracing_stop(void)
990 struct ring_buffer
*buffer
;
994 spin_lock_irqsave(&tracing_start_lock
, flags
);
995 if (trace_stop_count
++)
998 /* Prevent the buffers from switching */
999 arch_spin_lock(&ftrace_max_lock
);
1001 buffer
= global_trace
.buffer
;
1003 ring_buffer_record_disable(buffer
);
1005 buffer
= max_tr
.buffer
;
1007 ring_buffer_record_disable(buffer
);
1009 arch_spin_unlock(&ftrace_max_lock
);
1012 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
1015 void trace_stop_cmdline_recording(void);
1017 static void trace_save_cmdline(struct task_struct
*tsk
)
1021 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
1025 * It's not the end of the world if we don't get
1026 * the lock, but we also don't want to spin
1027 * nor do we want to disable interrupts,
1028 * so if we miss here, then better luck next time.
1030 if (!arch_spin_trylock(&trace_cmdline_lock
))
1033 idx
= map_pid_to_cmdline
[tsk
->pid
];
1034 if (idx
== NO_CMDLINE_MAP
) {
1035 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
1038 * Check whether the cmdline buffer at idx has a pid
1039 * mapped. We are going to overwrite that entry so we
1040 * need to clear the map_pid_to_cmdline. Otherwise we
1041 * would read the new comm for the old pid.
1043 pid
= map_cmdline_to_pid
[idx
];
1044 if (pid
!= NO_CMDLINE_MAP
)
1045 map_pid_to_cmdline
[pid
] = NO_CMDLINE_MAP
;
1047 map_cmdline_to_pid
[idx
] = tsk
->pid
;
1048 map_pid_to_cmdline
[tsk
->pid
] = idx
;
1053 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
1055 arch_spin_unlock(&trace_cmdline_lock
);
1058 void trace_find_cmdline(int pid
, char comm
[])
1063 strcpy(comm
, "<idle>");
1067 if (WARN_ON_ONCE(pid
< 0)) {
1068 strcpy(comm
, "<XXX>");
1072 if (pid
> PID_MAX_DEFAULT
) {
1073 strcpy(comm
, "<...>");
1078 arch_spin_lock(&trace_cmdline_lock
);
1079 map
= map_pid_to_cmdline
[pid
];
1080 if (map
!= NO_CMDLINE_MAP
)
1081 strcpy(comm
, saved_cmdlines
[map
]);
1083 strcpy(comm
, "<...>");
1085 arch_spin_unlock(&trace_cmdline_lock
);
1089 void tracing_record_cmdline(struct task_struct
*tsk
)
1091 if (atomic_read(&trace_record_cmdline_disabled
) || !tracer_enabled
||
1095 trace_save_cmdline(tsk
);
1099 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
,
1102 struct task_struct
*tsk
= current
;
1104 entry
->preempt_count
= pc
& 0xff;
1105 entry
->pid
= (tsk
) ? tsk
->pid
: 0;
1106 entry
->lock_depth
= (tsk
) ? tsk
->lock_depth
: 0;
1108 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1109 (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
1111 TRACE_FLAG_IRQS_NOSUPPORT
|
1113 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
1114 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
1115 (need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0);
1117 EXPORT_SYMBOL_GPL(tracing_generic_entry_update
);
1119 struct ring_buffer_event
*
1120 trace_buffer_lock_reserve(struct ring_buffer
*buffer
,
1123 unsigned long flags
, int pc
)
1125 struct ring_buffer_event
*event
;
1127 event
= ring_buffer_lock_reserve(buffer
, len
);
1128 if (event
!= NULL
) {
1129 struct trace_entry
*ent
= ring_buffer_event_data(event
);
1131 tracing_generic_entry_update(ent
, flags
, pc
);
1139 __trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1140 struct ring_buffer_event
*event
,
1141 unsigned long flags
, int pc
,
1144 ring_buffer_unlock_commit(buffer
, event
);
1146 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1147 ftrace_trace_userstack(buffer
, flags
, pc
);
1153 void trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1154 struct ring_buffer_event
*event
,
1155 unsigned long flags
, int pc
)
1157 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
, 1);
1160 struct ring_buffer_event
*
1161 trace_current_buffer_lock_reserve(struct ring_buffer
**current_rb
,
1162 int type
, unsigned long len
,
1163 unsigned long flags
, int pc
)
1165 *current_rb
= global_trace
.buffer
;
1166 return trace_buffer_lock_reserve(*current_rb
,
1167 type
, len
, flags
, pc
);
1169 EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve
);
1171 void trace_current_buffer_unlock_commit(struct ring_buffer
*buffer
,
1172 struct ring_buffer_event
*event
,
1173 unsigned long flags
, int pc
)
1175 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
, 1);
1177 EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit
);
1179 void trace_nowake_buffer_unlock_commit(struct ring_buffer
*buffer
,
1180 struct ring_buffer_event
*event
,
1181 unsigned long flags
, int pc
)
1183 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
, 0);
1185 EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit
);
1187 void trace_current_buffer_discard_commit(struct ring_buffer
*buffer
,
1188 struct ring_buffer_event
*event
)
1190 ring_buffer_discard_commit(buffer
, event
);
1192 EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit
);
1195 trace_function(struct trace_array
*tr
,
1196 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
1199 struct ftrace_event_call
*call
= &event_function
;
1200 struct ring_buffer
*buffer
= tr
->buffer
;
1201 struct ring_buffer_event
*event
;
1202 struct ftrace_entry
*entry
;
1204 /* If we are reading the ring buffer, don't trace */
1205 if (unlikely(__this_cpu_read(ftrace_cpu_disabled
)))
1208 event
= trace_buffer_lock_reserve(buffer
, TRACE_FN
, sizeof(*entry
),
1212 entry
= ring_buffer_event_data(event
);
1214 entry
->parent_ip
= parent_ip
;
1216 if (!filter_check_discard(call
, entry
, buffer
, event
))
1217 ring_buffer_unlock_commit(buffer
, event
);
1221 ftrace(struct trace_array
*tr
, struct trace_array_cpu
*data
,
1222 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
1225 if (likely(!atomic_read(&data
->disabled
)))
1226 trace_function(tr
, ip
, parent_ip
, flags
, pc
);
1229 #ifdef CONFIG_STACKTRACE
1230 static void __ftrace_trace_stack(struct ring_buffer
*buffer
,
1231 unsigned long flags
,
1234 struct ftrace_event_call
*call
= &event_kernel_stack
;
1235 struct ring_buffer_event
*event
;
1236 struct stack_entry
*entry
;
1237 struct stack_trace trace
;
1239 event
= trace_buffer_lock_reserve(buffer
, TRACE_STACK
,
1240 sizeof(*entry
), flags
, pc
);
1243 entry
= ring_buffer_event_data(event
);
1244 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
1246 trace
.nr_entries
= 0;
1247 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1249 trace
.entries
= entry
->caller
;
1251 save_stack_trace(&trace
);
1252 if (!filter_check_discard(call
, entry
, buffer
, event
))
1253 ring_buffer_unlock_commit(buffer
, event
);
1256 void ftrace_trace_stack(struct ring_buffer
*buffer
, unsigned long flags
,
1259 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1262 __ftrace_trace_stack(buffer
, flags
, skip
, pc
);
1265 void __trace_stack(struct trace_array
*tr
, unsigned long flags
, int skip
,
1268 __ftrace_trace_stack(tr
->buffer
, flags
, skip
, pc
);
1272 * trace_dump_stack - record a stack back trace in the trace buffer
1274 void trace_dump_stack(void)
1276 unsigned long flags
;
1278 if (tracing_disabled
|| tracing_selftest_running
)
1281 local_save_flags(flags
);
1283 /* skipping 3 traces, seems to get us at the caller of this function */
1284 __ftrace_trace_stack(global_trace
.buffer
, flags
, 3, preempt_count());
1288 ftrace_trace_userstack(struct ring_buffer
*buffer
, unsigned long flags
, int pc
)
1290 struct ftrace_event_call
*call
= &event_user_stack
;
1291 struct ring_buffer_event
*event
;
1292 struct userstack_entry
*entry
;
1293 struct stack_trace trace
;
1295 if (!(trace_flags
& TRACE_ITER_USERSTACKTRACE
))
1299 * NMIs can not handle page faults, even with fix ups.
1300 * The save user stack can (and often does) fault.
1302 if (unlikely(in_nmi()))
1305 event
= trace_buffer_lock_reserve(buffer
, TRACE_USER_STACK
,
1306 sizeof(*entry
), flags
, pc
);
1309 entry
= ring_buffer_event_data(event
);
1311 entry
->tgid
= current
->tgid
;
1312 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
1314 trace
.nr_entries
= 0;
1315 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1317 trace
.entries
= entry
->caller
;
1319 save_stack_trace_user(&trace
);
1320 if (!filter_check_discard(call
, entry
, buffer
, event
))
1321 ring_buffer_unlock_commit(buffer
, event
);
1325 static void __trace_userstack(struct trace_array
*tr
, unsigned long flags
)
1327 ftrace_trace_userstack(tr
, flags
, preempt_count());
1331 #endif /* CONFIG_STACKTRACE */
1334 * trace_vbprintk - write binary msg to tracing buffer
1337 int trace_vbprintk(unsigned long ip
, const char *fmt
, va_list args
)
1339 static arch_spinlock_t trace_buf_lock
=
1340 (arch_spinlock_t
)__ARCH_SPIN_LOCK_UNLOCKED
;
1341 static u32 trace_buf
[TRACE_BUF_SIZE
];
1343 struct ftrace_event_call
*call
= &event_bprint
;
1344 struct ring_buffer_event
*event
;
1345 struct ring_buffer
*buffer
;
1346 struct trace_array
*tr
= &global_trace
;
1347 struct trace_array_cpu
*data
;
1348 struct bprint_entry
*entry
;
1349 unsigned long flags
;
1351 int cpu
, len
= 0, size
, pc
;
1353 if (unlikely(tracing_selftest_running
|| tracing_disabled
))
1356 /* Don't pollute graph traces with trace_vprintk internals */
1357 pause_graph_tracing();
1359 pc
= preempt_count();
1360 preempt_disable_notrace();
1361 cpu
= raw_smp_processor_id();
1362 data
= tr
->data
[cpu
];
1364 disable
= atomic_inc_return(&data
->disabled
);
1365 if (unlikely(disable
!= 1))
1368 /* Lockdep uses trace_printk for lock tracing */
1369 local_irq_save(flags
);
1370 arch_spin_lock(&trace_buf_lock
);
1371 len
= vbin_printf(trace_buf
, TRACE_BUF_SIZE
, fmt
, args
);
1373 if (len
> TRACE_BUF_SIZE
|| len
< 0)
1376 size
= sizeof(*entry
) + sizeof(u32
) * len
;
1377 buffer
= tr
->buffer
;
1378 event
= trace_buffer_lock_reserve(buffer
, TRACE_BPRINT
, size
,
1382 entry
= ring_buffer_event_data(event
);
1386 memcpy(entry
->buf
, trace_buf
, sizeof(u32
) * len
);
1387 if (!filter_check_discard(call
, entry
, buffer
, event
)) {
1388 ring_buffer_unlock_commit(buffer
, event
);
1389 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1393 arch_spin_unlock(&trace_buf_lock
);
1394 local_irq_restore(flags
);
1397 atomic_dec_return(&data
->disabled
);
1398 preempt_enable_notrace();
1399 unpause_graph_tracing();
1403 EXPORT_SYMBOL_GPL(trace_vbprintk
);
1405 int trace_array_printk(struct trace_array
*tr
,
1406 unsigned long ip
, const char *fmt
, ...)
1411 if (!(trace_flags
& TRACE_ITER_PRINTK
))
1415 ret
= trace_array_vprintk(tr
, ip
, fmt
, ap
);
1420 int trace_array_vprintk(struct trace_array
*tr
,
1421 unsigned long ip
, const char *fmt
, va_list args
)
1423 static arch_spinlock_t trace_buf_lock
= __ARCH_SPIN_LOCK_UNLOCKED
;
1424 static char trace_buf
[TRACE_BUF_SIZE
];
1426 struct ftrace_event_call
*call
= &event_print
;
1427 struct ring_buffer_event
*event
;
1428 struct ring_buffer
*buffer
;
1429 struct trace_array_cpu
*data
;
1430 int cpu
, len
= 0, size
, pc
;
1431 struct print_entry
*entry
;
1432 unsigned long irq_flags
;
1435 if (tracing_disabled
|| tracing_selftest_running
)
1438 pc
= preempt_count();
1439 preempt_disable_notrace();
1440 cpu
= raw_smp_processor_id();
1441 data
= tr
->data
[cpu
];
1443 disable
= atomic_inc_return(&data
->disabled
);
1444 if (unlikely(disable
!= 1))
1447 pause_graph_tracing();
1448 raw_local_irq_save(irq_flags
);
1449 arch_spin_lock(&trace_buf_lock
);
1450 len
= vsnprintf(trace_buf
, TRACE_BUF_SIZE
, fmt
, args
);
1452 size
= sizeof(*entry
) + len
+ 1;
1453 buffer
= tr
->buffer
;
1454 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, size
,
1458 entry
= ring_buffer_event_data(event
);
1461 memcpy(&entry
->buf
, trace_buf
, len
);
1462 entry
->buf
[len
] = '\0';
1463 if (!filter_check_discard(call
, entry
, buffer
, event
)) {
1464 ring_buffer_unlock_commit(buffer
, event
);
1465 ftrace_trace_stack(buffer
, irq_flags
, 6, pc
);
1469 arch_spin_unlock(&trace_buf_lock
);
1470 raw_local_irq_restore(irq_flags
);
1471 unpause_graph_tracing();
1473 atomic_dec_return(&data
->disabled
);
1474 preempt_enable_notrace();
1479 int trace_vprintk(unsigned long ip
, const char *fmt
, va_list args
)
1481 return trace_array_vprintk(&global_trace
, ip
, fmt
, args
);
1483 EXPORT_SYMBOL_GPL(trace_vprintk
);
1485 static void trace_iterator_increment(struct trace_iterator
*iter
)
1487 /* Don't allow ftrace to trace into the ring buffers */
1488 ftrace_disable_cpu();
1491 if (iter
->buffer_iter
[iter
->cpu
])
1492 ring_buffer_read(iter
->buffer_iter
[iter
->cpu
], NULL
);
1494 ftrace_enable_cpu();
1497 static struct trace_entry
*
1498 peek_next_entry(struct trace_iterator
*iter
, int cpu
, u64
*ts
,
1499 unsigned long *lost_events
)
1501 struct ring_buffer_event
*event
;
1502 struct ring_buffer_iter
*buf_iter
= iter
->buffer_iter
[cpu
];
1504 /* Don't allow ftrace to trace into the ring buffers */
1505 ftrace_disable_cpu();
1508 event
= ring_buffer_iter_peek(buf_iter
, ts
);
1510 event
= ring_buffer_peek(iter
->tr
->buffer
, cpu
, ts
,
1513 ftrace_enable_cpu();
1515 return event
? ring_buffer_event_data(event
) : NULL
;
1518 static struct trace_entry
*
1519 __find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
,
1520 unsigned long *missing_events
, u64
*ent_ts
)
1522 struct ring_buffer
*buffer
= iter
->tr
->buffer
;
1523 struct trace_entry
*ent
, *next
= NULL
;
1524 unsigned long lost_events
= 0, next_lost
= 0;
1525 int cpu_file
= iter
->cpu_file
;
1526 u64 next_ts
= 0, ts
;
1531 * If we are in a per_cpu trace file, don't bother by iterating over
1532 * all cpu and peek directly.
1534 if (cpu_file
> TRACE_PIPE_ALL_CPU
) {
1535 if (ring_buffer_empty_cpu(buffer
, cpu_file
))
1537 ent
= peek_next_entry(iter
, cpu_file
, ent_ts
, missing_events
);
1539 *ent_cpu
= cpu_file
;
1544 for_each_tracing_cpu(cpu
) {
1546 if (ring_buffer_empty_cpu(buffer
, cpu
))
1549 ent
= peek_next_entry(iter
, cpu
, &ts
, &lost_events
);
1552 * Pick the entry with the smallest timestamp:
1554 if (ent
&& (!next
|| ts
< next_ts
)) {
1558 next_lost
= lost_events
;
1563 *ent_cpu
= next_cpu
;
1569 *missing_events
= next_lost
;
1574 /* Find the next real entry, without updating the iterator itself */
1575 struct trace_entry
*trace_find_next_entry(struct trace_iterator
*iter
,
1576 int *ent_cpu
, u64
*ent_ts
)
1578 return __find_next_entry(iter
, ent_cpu
, NULL
, ent_ts
);
1581 /* Find the next real entry, and increment the iterator to the next entry */
1582 void *trace_find_next_entry_inc(struct trace_iterator
*iter
)
1584 iter
->ent
= __find_next_entry(iter
, &iter
->cpu
,
1585 &iter
->lost_events
, &iter
->ts
);
1588 trace_iterator_increment(iter
);
1590 return iter
->ent
? iter
: NULL
;
1593 static void trace_consume(struct trace_iterator
*iter
)
1595 /* Don't allow ftrace to trace into the ring buffers */
1596 ftrace_disable_cpu();
1597 ring_buffer_consume(iter
->tr
->buffer
, iter
->cpu
, &iter
->ts
,
1598 &iter
->lost_events
);
1599 ftrace_enable_cpu();
1602 static void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1604 struct trace_iterator
*iter
= m
->private;
1608 WARN_ON_ONCE(iter
->leftover
);
1612 /* can't go backwards */
1617 ent
= trace_find_next_entry_inc(iter
);
1621 while (ent
&& iter
->idx
< i
)
1622 ent
= trace_find_next_entry_inc(iter
);
1629 void tracing_iter_reset(struct trace_iterator
*iter
, int cpu
)
1631 struct trace_array
*tr
= iter
->tr
;
1632 struct ring_buffer_event
*event
;
1633 struct ring_buffer_iter
*buf_iter
;
1634 unsigned long entries
= 0;
1637 tr
->data
[cpu
]->skipped_entries
= 0;
1639 if (!iter
->buffer_iter
[cpu
])
1642 buf_iter
= iter
->buffer_iter
[cpu
];
1643 ring_buffer_iter_reset(buf_iter
);
1646 * We could have the case with the max latency tracers
1647 * that a reset never took place on a cpu. This is evident
1648 * by the timestamp being before the start of the buffer.
1650 while ((event
= ring_buffer_iter_peek(buf_iter
, &ts
))) {
1651 if (ts
>= iter
->tr
->time_start
)
1654 ring_buffer_read(buf_iter
, NULL
);
1657 tr
->data
[cpu
]->skipped_entries
= entries
;
1661 * The current tracer is copied to avoid a global locking
1664 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
1666 struct trace_iterator
*iter
= m
->private;
1667 static struct tracer
*old_tracer
;
1668 int cpu_file
= iter
->cpu_file
;
1673 /* copy the tracer to avoid using a global lock all around */
1674 mutex_lock(&trace_types_lock
);
1675 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
1676 old_tracer
= current_trace
;
1677 *iter
->trace
= *current_trace
;
1679 mutex_unlock(&trace_types_lock
);
1681 atomic_inc(&trace_record_cmdline_disabled
);
1683 if (*pos
!= iter
->pos
) {
1688 ftrace_disable_cpu();
1690 if (cpu_file
== TRACE_PIPE_ALL_CPU
) {
1691 for_each_tracing_cpu(cpu
)
1692 tracing_iter_reset(iter
, cpu
);
1694 tracing_iter_reset(iter
, cpu_file
);
1696 ftrace_enable_cpu();
1699 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
1704 * If we overflowed the seq_file before, then we want
1705 * to just reuse the trace_seq buffer again.
1711 p
= s_next(m
, p
, &l
);
1715 trace_event_read_lock();
1716 trace_access_lock(cpu_file
);
1720 static void s_stop(struct seq_file
*m
, void *p
)
1722 struct trace_iterator
*iter
= m
->private;
1724 atomic_dec(&trace_record_cmdline_disabled
);
1725 trace_access_unlock(iter
->cpu_file
);
1726 trace_event_read_unlock();
1729 static void print_lat_help_header(struct seq_file
*m
)
1731 seq_puts(m
, "# _------=> CPU# \n");
1732 seq_puts(m
, "# / _-----=> irqs-off \n");
1733 seq_puts(m
, "# | / _----=> need-resched \n");
1734 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
1735 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
1736 seq_puts(m
, "# |||| /_--=> lock-depth \n");
1737 seq_puts(m
, "# |||||/ delay \n");
1738 seq_puts(m
, "# cmd pid |||||| time | caller \n");
1739 seq_puts(m
, "# \\ / |||||| \\ | / \n");
1742 static void print_func_help_header(struct seq_file
*m
)
1744 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1745 seq_puts(m
, "# | | | | |\n");
1750 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
1752 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1753 struct trace_array
*tr
= iter
->tr
;
1754 struct trace_array_cpu
*data
= tr
->data
[tr
->cpu
];
1755 struct tracer
*type
= current_trace
;
1756 unsigned long entries
= 0;
1757 unsigned long total
= 0;
1758 unsigned long count
;
1759 const char *name
= "preemption";
1766 for_each_tracing_cpu(cpu
) {
1767 count
= ring_buffer_entries_cpu(tr
->buffer
, cpu
);
1769 * If this buffer has skipped entries, then we hold all
1770 * entries for the trace and we need to ignore the
1771 * ones before the time stamp.
1773 if (tr
->data
[cpu
]->skipped_entries
) {
1774 count
-= tr
->data
[cpu
]->skipped_entries
;
1775 /* total is the same as the entries */
1779 ring_buffer_overrun_cpu(tr
->buffer
, cpu
);
1783 seq_printf(m
, "# %s latency trace v1.1.5 on %s\n",
1785 seq_puts(m
, "# -----------------------------------"
1786 "---------------------------------\n");
1787 seq_printf(m
, "# latency: %lu us, #%lu/%lu, CPU#%d |"
1788 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1789 nsecs_to_usecs(data
->saved_latency
),
1793 #if defined(CONFIG_PREEMPT_NONE)
1795 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1797 #elif defined(CONFIG_PREEMPT)
1802 /* These are reserved for later use */
1805 seq_printf(m
, " #P:%d)\n", num_online_cpus());
1809 seq_puts(m
, "# -----------------\n");
1810 seq_printf(m
, "# | task: %.16s-%d "
1811 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1812 data
->comm
, data
->pid
, data
->uid
, data
->nice
,
1813 data
->policy
, data
->rt_priority
);
1814 seq_puts(m
, "# -----------------\n");
1816 if (data
->critical_start
) {
1817 seq_puts(m
, "# => started at: ");
1818 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
1819 trace_print_seq(m
, &iter
->seq
);
1820 seq_puts(m
, "\n# => ended at: ");
1821 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
1822 trace_print_seq(m
, &iter
->seq
);
1823 seq_puts(m
, "\n#\n");
1829 static void test_cpu_buff_start(struct trace_iterator
*iter
)
1831 struct trace_seq
*s
= &iter
->seq
;
1833 if (!(trace_flags
& TRACE_ITER_ANNOTATE
))
1836 if (!(iter
->iter_flags
& TRACE_FILE_ANNOTATE
))
1839 if (cpumask_test_cpu(iter
->cpu
, iter
->started
))
1842 if (iter
->tr
->data
[iter
->cpu
]->skipped_entries
)
1845 cpumask_set_cpu(iter
->cpu
, iter
->started
);
1847 /* Don't print started cpu buffer for the first entry of the trace */
1849 trace_seq_printf(s
, "##### CPU %u buffer started ####\n",
1853 static enum print_line_t
print_trace_fmt(struct trace_iterator
*iter
)
1855 struct trace_seq
*s
= &iter
->seq
;
1856 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1857 struct trace_entry
*entry
;
1858 struct trace_event
*event
;
1862 test_cpu_buff_start(iter
);
1864 event
= ftrace_find_event(entry
->type
);
1866 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1867 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
1868 if (!trace_print_lat_context(iter
))
1871 if (!trace_print_context(iter
))
1877 return event
->funcs
->trace(iter
, sym_flags
, event
);
1879 if (!trace_seq_printf(s
, "Unknown type %d\n", entry
->type
))
1882 return TRACE_TYPE_HANDLED
;
1884 return TRACE_TYPE_PARTIAL_LINE
;
1887 static enum print_line_t
print_raw_fmt(struct trace_iterator
*iter
)
1889 struct trace_seq
*s
= &iter
->seq
;
1890 struct trace_entry
*entry
;
1891 struct trace_event
*event
;
1895 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1896 if (!trace_seq_printf(s
, "%d %d %llu ",
1897 entry
->pid
, iter
->cpu
, iter
->ts
))
1901 event
= ftrace_find_event(entry
->type
);
1903 return event
->funcs
->raw(iter
, 0, event
);
1905 if (!trace_seq_printf(s
, "%d ?\n", entry
->type
))
1908 return TRACE_TYPE_HANDLED
;
1910 return TRACE_TYPE_PARTIAL_LINE
;
1913 static enum print_line_t
print_hex_fmt(struct trace_iterator
*iter
)
1915 struct trace_seq
*s
= &iter
->seq
;
1916 unsigned char newline
= '\n';
1917 struct trace_entry
*entry
;
1918 struct trace_event
*event
;
1922 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1923 SEQ_PUT_HEX_FIELD_RET(s
, entry
->pid
);
1924 SEQ_PUT_HEX_FIELD_RET(s
, iter
->cpu
);
1925 SEQ_PUT_HEX_FIELD_RET(s
, iter
->ts
);
1928 event
= ftrace_find_event(entry
->type
);
1930 enum print_line_t ret
= event
->funcs
->hex(iter
, 0, event
);
1931 if (ret
!= TRACE_TYPE_HANDLED
)
1935 SEQ_PUT_FIELD_RET(s
, newline
);
1937 return TRACE_TYPE_HANDLED
;
1940 static enum print_line_t
print_bin_fmt(struct trace_iterator
*iter
)
1942 struct trace_seq
*s
= &iter
->seq
;
1943 struct trace_entry
*entry
;
1944 struct trace_event
*event
;
1948 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1949 SEQ_PUT_FIELD_RET(s
, entry
->pid
);
1950 SEQ_PUT_FIELD_RET(s
, iter
->cpu
);
1951 SEQ_PUT_FIELD_RET(s
, iter
->ts
);
1954 event
= ftrace_find_event(entry
->type
);
1955 return event
? event
->funcs
->binary(iter
, 0, event
) :
1959 int trace_empty(struct trace_iterator
*iter
)
1963 /* If we are looking at one CPU buffer, only check that one */
1964 if (iter
->cpu_file
!= TRACE_PIPE_ALL_CPU
) {
1965 cpu
= iter
->cpu_file
;
1966 if (iter
->buffer_iter
[cpu
]) {
1967 if (!ring_buffer_iter_empty(iter
->buffer_iter
[cpu
]))
1970 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
1976 for_each_tracing_cpu(cpu
) {
1977 if (iter
->buffer_iter
[cpu
]) {
1978 if (!ring_buffer_iter_empty(iter
->buffer_iter
[cpu
]))
1981 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
1989 /* Called with trace_event_read_lock() held. */
1990 enum print_line_t
print_trace_line(struct trace_iterator
*iter
)
1992 enum print_line_t ret
;
1994 if (iter
->lost_events
)
1995 trace_seq_printf(&iter
->seq
, "CPU:%d [LOST %lu EVENTS]\n",
1996 iter
->cpu
, iter
->lost_events
);
1998 if (iter
->trace
&& iter
->trace
->print_line
) {
1999 ret
= iter
->trace
->print_line(iter
);
2000 if (ret
!= TRACE_TYPE_UNHANDLED
)
2004 if (iter
->ent
->type
== TRACE_BPRINT
&&
2005 trace_flags
& TRACE_ITER_PRINTK
&&
2006 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2007 return trace_print_bprintk_msg_only(iter
);
2009 if (iter
->ent
->type
== TRACE_PRINT
&&
2010 trace_flags
& TRACE_ITER_PRINTK
&&
2011 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2012 return trace_print_printk_msg_only(iter
);
2014 if (trace_flags
& TRACE_ITER_BIN
)
2015 return print_bin_fmt(iter
);
2017 if (trace_flags
& TRACE_ITER_HEX
)
2018 return print_hex_fmt(iter
);
2020 if (trace_flags
& TRACE_ITER_RAW
)
2021 return print_raw_fmt(iter
);
2023 return print_trace_fmt(iter
);
2026 void trace_default_header(struct seq_file
*m
)
2028 struct trace_iterator
*iter
= m
->private;
2030 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
2031 /* print nothing if the buffers are empty */
2032 if (trace_empty(iter
))
2034 print_trace_header(m
, iter
);
2035 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2036 print_lat_help_header(m
);
2038 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2039 print_func_help_header(m
);
2043 static int s_show(struct seq_file
*m
, void *v
)
2045 struct trace_iterator
*iter
= v
;
2048 if (iter
->ent
== NULL
) {
2050 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
2053 if (iter
->trace
&& iter
->trace
->print_header
)
2054 iter
->trace
->print_header(m
);
2056 trace_default_header(m
);
2058 } else if (iter
->leftover
) {
2060 * If we filled the seq_file buffer earlier, we
2061 * want to just show it now.
2063 ret
= trace_print_seq(m
, &iter
->seq
);
2065 /* ret should this time be zero, but you never know */
2066 iter
->leftover
= ret
;
2069 print_trace_line(iter
);
2070 ret
= trace_print_seq(m
, &iter
->seq
);
2072 * If we overflow the seq_file buffer, then it will
2073 * ask us for this data again at start up.
2075 * ret is 0 if seq_file write succeeded.
2078 iter
->leftover
= ret
;
2084 static const struct seq_operations tracer_seq_ops
= {
2091 static struct trace_iterator
*
2092 __tracing_open(struct inode
*inode
, struct file
*file
)
2094 long cpu_file
= (long) inode
->i_private
;
2095 void *fail_ret
= ERR_PTR(-ENOMEM
);
2096 struct trace_iterator
*iter
;
2100 if (tracing_disabled
)
2101 return ERR_PTR(-ENODEV
);
2103 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2105 return ERR_PTR(-ENOMEM
);
2108 * We make a copy of the current tracer to avoid concurrent
2109 * changes on it while we are reading.
2111 mutex_lock(&trace_types_lock
);
2112 iter
->trace
= kzalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
2117 *iter
->trace
= *current_trace
;
2119 if (!zalloc_cpumask_var(&iter
->started
, GFP_KERNEL
))
2122 if (current_trace
&& current_trace
->print_max
)
2125 iter
->tr
= &global_trace
;
2127 mutex_init(&iter
->mutex
);
2128 iter
->cpu_file
= cpu_file
;
2130 /* Notify the tracer early; before we stop tracing. */
2131 if (iter
->trace
&& iter
->trace
->open
)
2132 iter
->trace
->open(iter
);
2134 /* Annotate start of buffers if we had overruns */
2135 if (ring_buffer_overruns(iter
->tr
->buffer
))
2136 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
2138 /* stop the trace while dumping */
2141 if (iter
->cpu_file
== TRACE_PIPE_ALL_CPU
) {
2142 for_each_tracing_cpu(cpu
) {
2143 iter
->buffer_iter
[cpu
] =
2144 ring_buffer_read_prepare(iter
->tr
->buffer
, cpu
);
2146 ring_buffer_read_prepare_sync();
2147 for_each_tracing_cpu(cpu
) {
2148 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2149 tracing_iter_reset(iter
, cpu
);
2152 cpu
= iter
->cpu_file
;
2153 iter
->buffer_iter
[cpu
] =
2154 ring_buffer_read_prepare(iter
->tr
->buffer
, cpu
);
2155 ring_buffer_read_prepare_sync();
2156 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2157 tracing_iter_reset(iter
, cpu
);
2160 ret
= seq_open(file
, &tracer_seq_ops
);
2162 fail_ret
= ERR_PTR(ret
);
2166 m
= file
->private_data
;
2169 mutex_unlock(&trace_types_lock
);
2174 for_each_tracing_cpu(cpu
) {
2175 if (iter
->buffer_iter
[cpu
])
2176 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
2178 free_cpumask_var(iter
->started
);
2181 mutex_unlock(&trace_types_lock
);
2188 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
2190 if (tracing_disabled
)
2193 filp
->private_data
= inode
->i_private
;
2197 static int tracing_release(struct inode
*inode
, struct file
*file
)
2199 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
2200 struct trace_iterator
*iter
;
2203 if (!(file
->f_mode
& FMODE_READ
))
2208 mutex_lock(&trace_types_lock
);
2209 for_each_tracing_cpu(cpu
) {
2210 if (iter
->buffer_iter
[cpu
])
2211 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
2214 if (iter
->trace
&& iter
->trace
->close
)
2215 iter
->trace
->close(iter
);
2217 /* reenable tracing if it was previously enabled */
2219 mutex_unlock(&trace_types_lock
);
2221 seq_release(inode
, file
);
2222 mutex_destroy(&iter
->mutex
);
2223 free_cpumask_var(iter
->started
);
2229 static int tracing_open(struct inode
*inode
, struct file
*file
)
2231 struct trace_iterator
*iter
;
2234 /* If this file was open for write, then erase contents */
2235 if ((file
->f_mode
& FMODE_WRITE
) &&
2236 (file
->f_flags
& O_TRUNC
)) {
2237 long cpu
= (long) inode
->i_private
;
2239 if (cpu
== TRACE_PIPE_ALL_CPU
)
2240 tracing_reset_online_cpus(&global_trace
);
2242 tracing_reset(&global_trace
, cpu
);
2245 if (file
->f_mode
& FMODE_READ
) {
2246 iter
= __tracing_open(inode
, file
);
2248 ret
= PTR_ERR(iter
);
2249 else if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
2250 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
2256 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
2258 struct tracer
*t
= v
;
2268 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
2273 mutex_lock(&trace_types_lock
);
2274 for (t
= trace_types
; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
2280 static void t_stop(struct seq_file
*m
, void *p
)
2282 mutex_unlock(&trace_types_lock
);
2285 static int t_show(struct seq_file
*m
, void *v
)
2287 struct tracer
*t
= v
;
2292 seq_printf(m
, "%s", t
->name
);
2301 static const struct seq_operations show_traces_seq_ops
= {
2308 static int show_traces_open(struct inode
*inode
, struct file
*file
)
2310 if (tracing_disabled
)
2313 return seq_open(file
, &show_traces_seq_ops
);
2317 tracing_write_stub(struct file
*filp
, const char __user
*ubuf
,
2318 size_t count
, loff_t
*ppos
)
2323 static loff_t
tracing_seek(struct file
*file
, loff_t offset
, int origin
)
2325 if (file
->f_mode
& FMODE_READ
)
2326 return seq_lseek(file
, offset
, origin
);
2331 static const struct file_operations tracing_fops
= {
2332 .open
= tracing_open
,
2334 .write
= tracing_write_stub
,
2335 .llseek
= tracing_seek
,
2336 .release
= tracing_release
,
2339 static const struct file_operations show_traces_fops
= {
2340 .open
= show_traces_open
,
2342 .release
= seq_release
,
2343 .llseek
= seq_lseek
,
2347 * Only trace on a CPU if the bitmask is set:
2349 static cpumask_var_t tracing_cpumask
;
2352 * The tracer itself will not take this lock, but still we want
2353 * to provide a consistent cpumask to user-space:
2355 static DEFINE_MUTEX(tracing_cpumask_update_lock
);
2358 * Temporary storage for the character representation of the
2359 * CPU bitmask (and one more byte for the newline):
2361 static char mask_str
[NR_CPUS
+ 1];
2364 tracing_cpumask_read(struct file
*filp
, char __user
*ubuf
,
2365 size_t count
, loff_t
*ppos
)
2369 mutex_lock(&tracing_cpumask_update_lock
);
2371 len
= cpumask_scnprintf(mask_str
, count
, tracing_cpumask
);
2372 if (count
- len
< 2) {
2376 len
+= sprintf(mask_str
+ len
, "\n");
2377 count
= simple_read_from_buffer(ubuf
, count
, ppos
, mask_str
, NR_CPUS
+1);
2380 mutex_unlock(&tracing_cpumask_update_lock
);
2386 tracing_cpumask_write(struct file
*filp
, const char __user
*ubuf
,
2387 size_t count
, loff_t
*ppos
)
2390 cpumask_var_t tracing_cpumask_new
;
2392 if (!alloc_cpumask_var(&tracing_cpumask_new
, GFP_KERNEL
))
2395 err
= cpumask_parse_user(ubuf
, count
, tracing_cpumask_new
);
2399 mutex_lock(&tracing_cpumask_update_lock
);
2401 local_irq_disable();
2402 arch_spin_lock(&ftrace_max_lock
);
2403 for_each_tracing_cpu(cpu
) {
2405 * Increase/decrease the disabled counter if we are
2406 * about to flip a bit in the cpumask:
2408 if (cpumask_test_cpu(cpu
, tracing_cpumask
) &&
2409 !cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
2410 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
2412 if (!cpumask_test_cpu(cpu
, tracing_cpumask
) &&
2413 cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
2414 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
2417 arch_spin_unlock(&ftrace_max_lock
);
2420 cpumask_copy(tracing_cpumask
, tracing_cpumask_new
);
2422 mutex_unlock(&tracing_cpumask_update_lock
);
2423 free_cpumask_var(tracing_cpumask_new
);
2428 free_cpumask_var(tracing_cpumask_new
);
2433 static const struct file_operations tracing_cpumask_fops
= {
2434 .open
= tracing_open_generic
,
2435 .read
= tracing_cpumask_read
,
2436 .write
= tracing_cpumask_write
,
2437 .llseek
= generic_file_llseek
,
2440 static int tracing_trace_options_show(struct seq_file
*m
, void *v
)
2442 struct tracer_opt
*trace_opts
;
2446 mutex_lock(&trace_types_lock
);
2447 tracer_flags
= current_trace
->flags
->val
;
2448 trace_opts
= current_trace
->flags
->opts
;
2450 for (i
= 0; trace_options
[i
]; i
++) {
2451 if (trace_flags
& (1 << i
))
2452 seq_printf(m
, "%s\n", trace_options
[i
]);
2454 seq_printf(m
, "no%s\n", trace_options
[i
]);
2457 for (i
= 0; trace_opts
[i
].name
; i
++) {
2458 if (tracer_flags
& trace_opts
[i
].bit
)
2459 seq_printf(m
, "%s\n", trace_opts
[i
].name
);
2461 seq_printf(m
, "no%s\n", trace_opts
[i
].name
);
2463 mutex_unlock(&trace_types_lock
);
2468 static int __set_tracer_option(struct tracer
*trace
,
2469 struct tracer_flags
*tracer_flags
,
2470 struct tracer_opt
*opts
, int neg
)
2474 ret
= trace
->set_flag(tracer_flags
->val
, opts
->bit
, !neg
);
2479 tracer_flags
->val
&= ~opts
->bit
;
2481 tracer_flags
->val
|= opts
->bit
;
2485 /* Try to assign a tracer specific option */
2486 static int set_tracer_option(struct tracer
*trace
, char *cmp
, int neg
)
2488 struct tracer_flags
*tracer_flags
= trace
->flags
;
2489 struct tracer_opt
*opts
= NULL
;
2492 for (i
= 0; tracer_flags
->opts
[i
].name
; i
++) {
2493 opts
= &tracer_flags
->opts
[i
];
2495 if (strcmp(cmp
, opts
->name
) == 0)
2496 return __set_tracer_option(trace
, trace
->flags
,
2503 static void set_tracer_flags(unsigned int mask
, int enabled
)
2505 /* do nothing if flag is already set */
2506 if (!!(trace_flags
& mask
) == !!enabled
)
2510 trace_flags
|= mask
;
2512 trace_flags
&= ~mask
;
2514 if (mask
== TRACE_ITER_RECORD_CMD
)
2515 trace_event_enable_cmd_record(enabled
);
2519 tracing_trace_options_write(struct file
*filp
, const char __user
*ubuf
,
2520 size_t cnt
, loff_t
*ppos
)
2528 if (cnt
>= sizeof(buf
))
2531 if (copy_from_user(&buf
, ubuf
, cnt
))
2535 cmp
= strstrip(buf
);
2537 if (strncmp(cmp
, "no", 2) == 0) {
2542 for (i
= 0; trace_options
[i
]; i
++) {
2543 if (strcmp(cmp
, trace_options
[i
]) == 0) {
2544 set_tracer_flags(1 << i
, !neg
);
2549 /* If no option could be set, test the specific tracer options */
2550 if (!trace_options
[i
]) {
2551 mutex_lock(&trace_types_lock
);
2552 ret
= set_tracer_option(current_trace
, cmp
, neg
);
2553 mutex_unlock(&trace_types_lock
);
2563 static int tracing_trace_options_open(struct inode
*inode
, struct file
*file
)
2565 if (tracing_disabled
)
2567 return single_open(file
, tracing_trace_options_show
, NULL
);
2570 static const struct file_operations tracing_iter_fops
= {
2571 .open
= tracing_trace_options_open
,
2573 .llseek
= seq_lseek
,
2574 .release
= single_release
,
2575 .write
= tracing_trace_options_write
,
2578 static const char readme_msg
[] =
2579 "tracing mini-HOWTO:\n\n"
2580 "# mount -t debugfs nodev /sys/kernel/debug\n\n"
2581 "# cat /sys/kernel/debug/tracing/available_tracers\n"
2582 "wakeup preemptirqsoff preemptoff irqsoff function sched_switch nop\n\n"
2583 "# cat /sys/kernel/debug/tracing/current_tracer\n"
2585 "# echo sched_switch > /sys/kernel/debug/tracing/current_tracer\n"
2586 "# cat /sys/kernel/debug/tracing/current_tracer\n"
2588 "# cat /sys/kernel/debug/tracing/trace_options\n"
2589 "noprint-parent nosym-offset nosym-addr noverbose\n"
2590 "# echo print-parent > /sys/kernel/debug/tracing/trace_options\n"
2591 "# echo 1 > /sys/kernel/debug/tracing/tracing_enabled\n"
2592 "# cat /sys/kernel/debug/tracing/trace > /tmp/trace.txt\n"
2593 "# echo 0 > /sys/kernel/debug/tracing/tracing_enabled\n"
2597 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
2598 size_t cnt
, loff_t
*ppos
)
2600 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
2601 readme_msg
, strlen(readme_msg
));
2604 static const struct file_operations tracing_readme_fops
= {
2605 .open
= tracing_open_generic
,
2606 .read
= tracing_readme_read
,
2607 .llseek
= generic_file_llseek
,
2611 tracing_saved_cmdlines_read(struct file
*file
, char __user
*ubuf
,
2612 size_t cnt
, loff_t
*ppos
)
2621 file_buf
= kmalloc(SAVED_CMDLINES
*(16+TASK_COMM_LEN
), GFP_KERNEL
);
2625 buf_comm
= kmalloc(TASK_COMM_LEN
, GFP_KERNEL
);
2633 for (i
= 0; i
< SAVED_CMDLINES
; i
++) {
2636 pid
= map_cmdline_to_pid
[i
];
2637 if (pid
== -1 || pid
== NO_CMDLINE_MAP
)
2640 trace_find_cmdline(pid
, buf_comm
);
2641 r
= sprintf(buf
, "%d %s\n", pid
, buf_comm
);
2646 len
= simple_read_from_buffer(ubuf
, cnt
, ppos
,
2655 static const struct file_operations tracing_saved_cmdlines_fops
= {
2656 .open
= tracing_open_generic
,
2657 .read
= tracing_saved_cmdlines_read
,
2658 .llseek
= generic_file_llseek
,
2662 tracing_ctrl_read(struct file
*filp
, char __user
*ubuf
,
2663 size_t cnt
, loff_t
*ppos
)
2668 r
= sprintf(buf
, "%u\n", tracer_enabled
);
2669 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2673 tracing_ctrl_write(struct file
*filp
, const char __user
*ubuf
,
2674 size_t cnt
, loff_t
*ppos
)
2676 struct trace_array
*tr
= filp
->private_data
;
2681 if (cnt
>= sizeof(buf
))
2684 if (copy_from_user(&buf
, ubuf
, cnt
))
2689 ret
= strict_strtoul(buf
, 10, &val
);
2695 mutex_lock(&trace_types_lock
);
2696 if (tracer_enabled
^ val
) {
2699 if (current_trace
->start
)
2700 current_trace
->start(tr
);
2705 if (current_trace
->stop
)
2706 current_trace
->stop(tr
);
2709 mutex_unlock(&trace_types_lock
);
2717 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
2718 size_t cnt
, loff_t
*ppos
)
2720 char buf
[MAX_TRACER_SIZE
+2];
2723 mutex_lock(&trace_types_lock
);
2725 r
= sprintf(buf
, "%s\n", current_trace
->name
);
2727 r
= sprintf(buf
, "\n");
2728 mutex_unlock(&trace_types_lock
);
2730 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2733 int tracer_init(struct tracer
*t
, struct trace_array
*tr
)
2735 tracing_reset_online_cpus(tr
);
2739 static int tracing_resize_ring_buffer(unsigned long size
)
2744 * If kernel or user changes the size of the ring buffer
2745 * we use the size that was given, and we can forget about
2746 * expanding it later.
2748 ring_buffer_expanded
= 1;
2750 ret
= ring_buffer_resize(global_trace
.buffer
, size
);
2754 if (!current_trace
->use_max_tr
)
2757 ret
= ring_buffer_resize(max_tr
.buffer
, size
);
2761 r
= ring_buffer_resize(global_trace
.buffer
,
2762 global_trace
.entries
);
2765 * AARGH! We are left with different
2766 * size max buffer!!!!
2767 * The max buffer is our "snapshot" buffer.
2768 * When a tracer needs a snapshot (one of the
2769 * latency tracers), it swaps the max buffer
2770 * with the saved snap shot. We succeeded to
2771 * update the size of the main buffer, but failed to
2772 * update the size of the max buffer. But when we tried
2773 * to reset the main buffer to the original size, we
2774 * failed there too. This is very unlikely to
2775 * happen, but if it does, warn and kill all
2779 tracing_disabled
= 1;
2784 max_tr
.entries
= size
;
2786 global_trace
.entries
= size
;
2793 * tracing_update_buffers - used by tracing facility to expand ring buffers
2795 * To save on memory when the tracing is never used on a system with it
2796 * configured in. The ring buffers are set to a minimum size. But once
2797 * a user starts to use the tracing facility, then they need to grow
2798 * to their default size.
2800 * This function is to be called when a tracer is about to be used.
2802 int tracing_update_buffers(void)
2806 mutex_lock(&trace_types_lock
);
2807 if (!ring_buffer_expanded
)
2808 ret
= tracing_resize_ring_buffer(trace_buf_size
);
2809 mutex_unlock(&trace_types_lock
);
2814 struct trace_option_dentry
;
2816 static struct trace_option_dentry
*
2817 create_trace_option_files(struct tracer
*tracer
);
2820 destroy_trace_option_files(struct trace_option_dentry
*topts
);
2822 static int tracing_set_tracer(const char *buf
)
2824 static struct trace_option_dentry
*topts
;
2825 struct trace_array
*tr
= &global_trace
;
2829 mutex_lock(&trace_types_lock
);
2831 if (!ring_buffer_expanded
) {
2832 ret
= tracing_resize_ring_buffer(trace_buf_size
);
2838 for (t
= trace_types
; t
; t
= t
->next
) {
2839 if (strcmp(t
->name
, buf
) == 0)
2846 if (t
== current_trace
)
2849 trace_branch_disable();
2850 if (current_trace
&& current_trace
->reset
)
2851 current_trace
->reset(tr
);
2852 if (current_trace
&& current_trace
->use_max_tr
) {
2854 * We don't free the ring buffer. instead, resize it because
2855 * The max_tr ring buffer has some state (e.g. ring->clock) and
2856 * we want preserve it.
2858 ring_buffer_resize(max_tr
.buffer
, 1);
2861 destroy_trace_option_files(topts
);
2865 topts
= create_trace_option_files(current_trace
);
2866 if (current_trace
->use_max_tr
) {
2867 ret
= ring_buffer_resize(max_tr
.buffer
, global_trace
.entries
);
2870 max_tr
.entries
= global_trace
.entries
;
2874 ret
= tracer_init(t
, tr
);
2879 trace_branch_enable(tr
);
2881 mutex_unlock(&trace_types_lock
);
2887 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
2888 size_t cnt
, loff_t
*ppos
)
2890 char buf
[MAX_TRACER_SIZE
+1];
2897 if (cnt
> MAX_TRACER_SIZE
)
2898 cnt
= MAX_TRACER_SIZE
;
2900 if (copy_from_user(&buf
, ubuf
, cnt
))
2905 /* strip ending whitespace. */
2906 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
2909 err
= tracing_set_tracer(buf
);
2919 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
2920 size_t cnt
, loff_t
*ppos
)
2922 unsigned long *ptr
= filp
->private_data
;
2926 r
= snprintf(buf
, sizeof(buf
), "%ld\n",
2927 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
2928 if (r
> sizeof(buf
))
2930 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2934 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
2935 size_t cnt
, loff_t
*ppos
)
2937 unsigned long *ptr
= filp
->private_data
;
2942 if (cnt
>= sizeof(buf
))
2945 if (copy_from_user(&buf
, ubuf
, cnt
))
2950 ret
= strict_strtoul(buf
, 10, &val
);
2959 static int tracing_open_pipe(struct inode
*inode
, struct file
*filp
)
2961 long cpu_file
= (long) inode
->i_private
;
2962 struct trace_iterator
*iter
;
2965 if (tracing_disabled
)
2968 mutex_lock(&trace_types_lock
);
2970 /* create a buffer to store the information to pass to userspace */
2971 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2978 * We make a copy of the current tracer to avoid concurrent
2979 * changes on it while we are reading.
2981 iter
->trace
= kmalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
2987 *iter
->trace
= *current_trace
;
2989 if (!alloc_cpumask_var(&iter
->started
, GFP_KERNEL
)) {
2994 /* trace pipe does not show start of buffer */
2995 cpumask_setall(iter
->started
);
2997 if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
2998 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
3000 iter
->cpu_file
= cpu_file
;
3001 iter
->tr
= &global_trace
;
3002 mutex_init(&iter
->mutex
);
3003 filp
->private_data
= iter
;
3005 if (iter
->trace
->pipe_open
)
3006 iter
->trace
->pipe_open(iter
);
3008 nonseekable_open(inode
, filp
);
3010 mutex_unlock(&trace_types_lock
);
3016 mutex_unlock(&trace_types_lock
);
3020 static int tracing_release_pipe(struct inode
*inode
, struct file
*file
)
3022 struct trace_iterator
*iter
= file
->private_data
;
3024 mutex_lock(&trace_types_lock
);
3026 if (iter
->trace
->pipe_close
)
3027 iter
->trace
->pipe_close(iter
);
3029 mutex_unlock(&trace_types_lock
);
3031 free_cpumask_var(iter
->started
);
3032 mutex_destroy(&iter
->mutex
);
3040 tracing_poll_pipe(struct file
*filp
, poll_table
*poll_table
)
3042 struct trace_iterator
*iter
= filp
->private_data
;
3044 if (trace_flags
& TRACE_ITER_BLOCK
) {
3046 * Always select as readable when in blocking mode
3048 return POLLIN
| POLLRDNORM
;
3050 if (!trace_empty(iter
))
3051 return POLLIN
| POLLRDNORM
;
3052 poll_wait(filp
, &trace_wait
, poll_table
);
3053 if (!trace_empty(iter
))
3054 return POLLIN
| POLLRDNORM
;
3061 void default_wait_pipe(struct trace_iterator
*iter
)
3065 prepare_to_wait(&trace_wait
, &wait
, TASK_INTERRUPTIBLE
);
3067 if (trace_empty(iter
))
3070 finish_wait(&trace_wait
, &wait
);
3074 * This is a make-shift waitqueue.
3075 * A tracer might use this callback on some rare cases:
3077 * 1) the current tracer might hold the runqueue lock when it wakes up
3078 * a reader, hence a deadlock (sched, function, and function graph tracers)
3079 * 2) the function tracers, trace all functions, we don't want
3080 * the overhead of calling wake_up and friends
3081 * (and tracing them too)
3083 * Anyway, this is really very primitive wakeup.
3085 void poll_wait_pipe(struct trace_iterator
*iter
)
3087 set_current_state(TASK_INTERRUPTIBLE
);
3088 /* sleep for 100 msecs, and try again. */
3089 schedule_timeout(HZ
/ 10);
3092 /* Must be called with trace_types_lock mutex held. */
3093 static int tracing_wait_pipe(struct file
*filp
)
3095 struct trace_iterator
*iter
= filp
->private_data
;
3097 while (trace_empty(iter
)) {
3099 if ((filp
->f_flags
& O_NONBLOCK
)) {
3103 mutex_unlock(&iter
->mutex
);
3105 iter
->trace
->wait_pipe(iter
);
3107 mutex_lock(&iter
->mutex
);
3109 if (signal_pending(current
))
3113 * We block until we read something and tracing is disabled.
3114 * We still block if tracing is disabled, but we have never
3115 * read anything. This allows a user to cat this file, and
3116 * then enable tracing. But after we have read something,
3117 * we give an EOF when tracing is again disabled.
3119 * iter->pos will be 0 if we haven't read anything.
3121 if (!tracer_enabled
&& iter
->pos
)
3132 tracing_read_pipe(struct file
*filp
, char __user
*ubuf
,
3133 size_t cnt
, loff_t
*ppos
)
3135 struct trace_iterator
*iter
= filp
->private_data
;
3136 static struct tracer
*old_tracer
;
3139 /* return any leftover data */
3140 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
3144 trace_seq_init(&iter
->seq
);
3146 /* copy the tracer to avoid using a global lock all around */
3147 mutex_lock(&trace_types_lock
);
3148 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
3149 old_tracer
= current_trace
;
3150 *iter
->trace
= *current_trace
;
3152 mutex_unlock(&trace_types_lock
);
3155 * Avoid more than one consumer on a single file descriptor
3156 * This is just a matter of traces coherency, the ring buffer itself
3159 mutex_lock(&iter
->mutex
);
3160 if (iter
->trace
->read
) {
3161 sret
= iter
->trace
->read(iter
, filp
, ubuf
, cnt
, ppos
);
3167 sret
= tracing_wait_pipe(filp
);
3171 /* stop when tracing is finished */
3172 if (trace_empty(iter
)) {
3177 if (cnt
>= PAGE_SIZE
)
3178 cnt
= PAGE_SIZE
- 1;
3180 /* reset all but tr, trace, and overruns */
3181 memset(&iter
->seq
, 0,
3182 sizeof(struct trace_iterator
) -
3183 offsetof(struct trace_iterator
, seq
));
3186 trace_event_read_lock();
3187 trace_access_lock(iter
->cpu_file
);
3188 while (trace_find_next_entry_inc(iter
) != NULL
) {
3189 enum print_line_t ret
;
3190 int len
= iter
->seq
.len
;
3192 ret
= print_trace_line(iter
);
3193 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
3194 /* don't print partial lines */
3195 iter
->seq
.len
= len
;
3198 if (ret
!= TRACE_TYPE_NO_CONSUME
)
3199 trace_consume(iter
);
3201 if (iter
->seq
.len
>= cnt
)
3204 trace_access_unlock(iter
->cpu_file
);
3205 trace_event_read_unlock();
3207 /* Now copy what we have to the user */
3208 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
3209 if (iter
->seq
.readpos
>= iter
->seq
.len
)
3210 trace_seq_init(&iter
->seq
);
3213 * If there was nothing to send to user, inspite of consuming trace
3214 * entries, go back to wait for more entries.
3220 mutex_unlock(&iter
->mutex
);
3225 static void tracing_pipe_buf_release(struct pipe_inode_info
*pipe
,
3226 struct pipe_buffer
*buf
)
3228 __free_page(buf
->page
);
3231 static void tracing_spd_release_pipe(struct splice_pipe_desc
*spd
,
3234 __free_page(spd
->pages
[idx
]);
3237 static const struct pipe_buf_operations tracing_pipe_buf_ops
= {
3239 .map
= generic_pipe_buf_map
,
3240 .unmap
= generic_pipe_buf_unmap
,
3241 .confirm
= generic_pipe_buf_confirm
,
3242 .release
= tracing_pipe_buf_release
,
3243 .steal
= generic_pipe_buf_steal
,
3244 .get
= generic_pipe_buf_get
,
3248 tracing_fill_pipe_page(size_t rem
, struct trace_iterator
*iter
)
3253 /* Seq buffer is page-sized, exactly what we need. */
3255 count
= iter
->seq
.len
;
3256 ret
= print_trace_line(iter
);
3257 count
= iter
->seq
.len
- count
;
3260 iter
->seq
.len
-= count
;
3263 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
3264 iter
->seq
.len
-= count
;
3268 if (ret
!= TRACE_TYPE_NO_CONSUME
)
3269 trace_consume(iter
);
3271 if (!trace_find_next_entry_inc(iter
)) {
3281 static ssize_t
tracing_splice_read_pipe(struct file
*filp
,
3283 struct pipe_inode_info
*pipe
,
3287 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
3288 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
3289 struct trace_iterator
*iter
= filp
->private_data
;
3290 struct splice_pipe_desc spd
= {
3292 .partial
= partial_def
,
3293 .nr_pages
= 0, /* This gets updated below. */
3295 .ops
= &tracing_pipe_buf_ops
,
3296 .spd_release
= tracing_spd_release_pipe
,
3298 static struct tracer
*old_tracer
;
3303 if (splice_grow_spd(pipe
, &spd
))
3306 /* copy the tracer to avoid using a global lock all around */
3307 mutex_lock(&trace_types_lock
);
3308 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
3309 old_tracer
= current_trace
;
3310 *iter
->trace
= *current_trace
;
3312 mutex_unlock(&trace_types_lock
);
3314 mutex_lock(&iter
->mutex
);
3316 if (iter
->trace
->splice_read
) {
3317 ret
= iter
->trace
->splice_read(iter
, filp
,
3318 ppos
, pipe
, len
, flags
);
3323 ret
= tracing_wait_pipe(filp
);
3327 if (!iter
->ent
&& !trace_find_next_entry_inc(iter
)) {
3332 trace_event_read_lock();
3333 trace_access_lock(iter
->cpu_file
);
3335 /* Fill as many pages as possible. */
3336 for (i
= 0, rem
= len
; i
< pipe
->buffers
&& rem
; i
++) {
3337 spd
.pages
[i
] = alloc_page(GFP_KERNEL
);
3341 rem
= tracing_fill_pipe_page(rem
, iter
);
3343 /* Copy the data into the page, so we can start over. */
3344 ret
= trace_seq_to_buffer(&iter
->seq
,
3345 page_address(spd
.pages
[i
]),
3348 __free_page(spd
.pages
[i
]);
3351 spd
.partial
[i
].offset
= 0;
3352 spd
.partial
[i
].len
= iter
->seq
.len
;
3354 trace_seq_init(&iter
->seq
);
3357 trace_access_unlock(iter
->cpu_file
);
3358 trace_event_read_unlock();
3359 mutex_unlock(&iter
->mutex
);
3363 ret
= splice_to_pipe(pipe
, &spd
);
3365 splice_shrink_spd(pipe
, &spd
);
3369 mutex_unlock(&iter
->mutex
);
3374 tracing_entries_read(struct file
*filp
, char __user
*ubuf
,
3375 size_t cnt
, loff_t
*ppos
)
3377 struct trace_array
*tr
= filp
->private_data
;
3381 mutex_lock(&trace_types_lock
);
3382 if (!ring_buffer_expanded
)
3383 r
= sprintf(buf
, "%lu (expanded: %lu)\n",
3385 trace_buf_size
>> 10);
3387 r
= sprintf(buf
, "%lu\n", tr
->entries
>> 10);
3388 mutex_unlock(&trace_types_lock
);
3390 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3394 tracing_entries_write(struct file
*filp
, const char __user
*ubuf
,
3395 size_t cnt
, loff_t
*ppos
)
3401 if (cnt
>= sizeof(buf
))
3404 if (copy_from_user(&buf
, ubuf
, cnt
))
3409 ret
= strict_strtoul(buf
, 10, &val
);
3413 /* must have at least 1 entry */
3417 mutex_lock(&trace_types_lock
);
3421 /* disable all cpu buffers */
3422 for_each_tracing_cpu(cpu
) {
3423 if (global_trace
.data
[cpu
])
3424 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
3425 if (max_tr
.data
[cpu
])
3426 atomic_inc(&max_tr
.data
[cpu
]->disabled
);
3429 /* value is in KB */
3432 if (val
!= global_trace
.entries
) {
3433 ret
= tracing_resize_ring_buffer(val
);
3442 /* If check pages failed, return ENOMEM */
3443 if (tracing_disabled
)
3446 for_each_tracing_cpu(cpu
) {
3447 if (global_trace
.data
[cpu
])
3448 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
3449 if (max_tr
.data
[cpu
])
3450 atomic_dec(&max_tr
.data
[cpu
]->disabled
);
3454 mutex_unlock(&trace_types_lock
);
3459 static int mark_printk(const char *fmt
, ...)
3463 va_start(args
, fmt
);
3464 ret
= trace_vprintk(0, fmt
, args
);
3470 tracing_mark_write(struct file
*filp
, const char __user
*ubuf
,
3471 size_t cnt
, loff_t
*fpos
)
3476 if (tracing_disabled
)
3479 if (cnt
> TRACE_BUF_SIZE
)
3480 cnt
= TRACE_BUF_SIZE
;
3482 buf
= kmalloc(cnt
+ 2, GFP_KERNEL
);
3486 if (copy_from_user(buf
, ubuf
, cnt
)) {
3490 if (buf
[cnt
-1] != '\n') {
3496 written
= mark_printk("%s", buf
);
3500 /* don't tell userspace we wrote more - it might confuse them */
3507 static int tracing_clock_show(struct seq_file
*m
, void *v
)
3511 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++)
3513 "%s%s%s%s", i
? " " : "",
3514 i
== trace_clock_id
? "[" : "", trace_clocks
[i
].name
,
3515 i
== trace_clock_id
? "]" : "");
3521 static ssize_t
tracing_clock_write(struct file
*filp
, const char __user
*ubuf
,
3522 size_t cnt
, loff_t
*fpos
)
3525 const char *clockstr
;
3528 if (cnt
>= sizeof(buf
))
3531 if (copy_from_user(&buf
, ubuf
, cnt
))
3536 clockstr
= strstrip(buf
);
3538 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++) {
3539 if (strcmp(trace_clocks
[i
].name
, clockstr
) == 0)
3542 if (i
== ARRAY_SIZE(trace_clocks
))
3547 mutex_lock(&trace_types_lock
);
3549 ring_buffer_set_clock(global_trace
.buffer
, trace_clocks
[i
].func
);
3551 ring_buffer_set_clock(max_tr
.buffer
, trace_clocks
[i
].func
);
3553 mutex_unlock(&trace_types_lock
);
3560 static int tracing_clock_open(struct inode
*inode
, struct file
*file
)
3562 if (tracing_disabled
)
3564 return single_open(file
, tracing_clock_show
, NULL
);
3567 static const struct file_operations tracing_max_lat_fops
= {
3568 .open
= tracing_open_generic
,
3569 .read
= tracing_max_lat_read
,
3570 .write
= tracing_max_lat_write
,
3571 .llseek
= generic_file_llseek
,
3574 static const struct file_operations tracing_ctrl_fops
= {
3575 .open
= tracing_open_generic
,
3576 .read
= tracing_ctrl_read
,
3577 .write
= tracing_ctrl_write
,
3578 .llseek
= generic_file_llseek
,
3581 static const struct file_operations set_tracer_fops
= {
3582 .open
= tracing_open_generic
,
3583 .read
= tracing_set_trace_read
,
3584 .write
= tracing_set_trace_write
,
3585 .llseek
= generic_file_llseek
,
3588 static const struct file_operations tracing_pipe_fops
= {
3589 .open
= tracing_open_pipe
,
3590 .poll
= tracing_poll_pipe
,
3591 .read
= tracing_read_pipe
,
3592 .splice_read
= tracing_splice_read_pipe
,
3593 .release
= tracing_release_pipe
,
3594 .llseek
= no_llseek
,
3597 static const struct file_operations tracing_entries_fops
= {
3598 .open
= tracing_open_generic
,
3599 .read
= tracing_entries_read
,
3600 .write
= tracing_entries_write
,
3601 .llseek
= generic_file_llseek
,
3604 static const struct file_operations tracing_mark_fops
= {
3605 .open
= tracing_open_generic
,
3606 .write
= tracing_mark_write
,
3607 .llseek
= generic_file_llseek
,
3610 static const struct file_operations trace_clock_fops
= {
3611 .open
= tracing_clock_open
,
3613 .llseek
= seq_lseek
,
3614 .release
= single_release
,
3615 .write
= tracing_clock_write
,
3618 struct ftrace_buffer_info
{
3619 struct trace_array
*tr
;
3625 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
)
3627 int cpu
= (int)(long)inode
->i_private
;
3628 struct ftrace_buffer_info
*info
;
3630 if (tracing_disabled
)
3633 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
3637 info
->tr
= &global_trace
;
3640 /* Force reading ring buffer for first read */
3641 info
->read
= (unsigned int)-1;
3643 filp
->private_data
= info
;
3645 return nonseekable_open(inode
, filp
);
3649 tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
3650 size_t count
, loff_t
*ppos
)
3652 struct ftrace_buffer_info
*info
= filp
->private_data
;
3660 info
->spare
= ring_buffer_alloc_read_page(info
->tr
->buffer
);
3664 /* Do we have previous read data to read? */
3665 if (info
->read
< PAGE_SIZE
)
3670 trace_access_lock(info
->cpu
);
3671 ret
= ring_buffer_read_page(info
->tr
->buffer
,
3675 trace_access_unlock(info
->cpu
);
3680 size
= PAGE_SIZE
- info
->read
;
3684 ret
= copy_to_user(ubuf
, info
->spare
+ info
->read
, size
);
3695 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
)
3697 struct ftrace_buffer_info
*info
= file
->private_data
;
3700 ring_buffer_free_read_page(info
->tr
->buffer
, info
->spare
);
3707 struct ring_buffer
*buffer
;
3712 static void buffer_pipe_buf_release(struct pipe_inode_info
*pipe
,
3713 struct pipe_buffer
*buf
)
3715 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
3720 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
3725 static int buffer_pipe_buf_steal(struct pipe_inode_info
*pipe
,
3726 struct pipe_buffer
*buf
)
3731 static void buffer_pipe_buf_get(struct pipe_inode_info
*pipe
,
3732 struct pipe_buffer
*buf
)
3734 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
3739 /* Pipe buffer operations for a buffer. */
3740 static const struct pipe_buf_operations buffer_pipe_buf_ops
= {
3742 .map
= generic_pipe_buf_map
,
3743 .unmap
= generic_pipe_buf_unmap
,
3744 .confirm
= generic_pipe_buf_confirm
,
3745 .release
= buffer_pipe_buf_release
,
3746 .steal
= buffer_pipe_buf_steal
,
3747 .get
= buffer_pipe_buf_get
,
3751 * Callback from splice_to_pipe(), if we need to release some pages
3752 * at the end of the spd in case we error'ed out in filling the pipe.
3754 static void buffer_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
3756 struct buffer_ref
*ref
=
3757 (struct buffer_ref
*)spd
->partial
[i
].private;
3762 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
3764 spd
->partial
[i
].private = 0;
3768 tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
3769 struct pipe_inode_info
*pipe
, size_t len
,
3772 struct ftrace_buffer_info
*info
= file
->private_data
;
3773 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
3774 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
3775 struct splice_pipe_desc spd
= {
3777 .partial
= partial_def
,
3779 .ops
= &buffer_pipe_buf_ops
,
3780 .spd_release
= buffer_spd_release
,
3782 struct buffer_ref
*ref
;
3783 int entries
, size
, i
;
3786 if (splice_grow_spd(pipe
, &spd
))
3789 if (*ppos
& (PAGE_SIZE
- 1)) {
3790 WARN_ONCE(1, "Ftrace: previous read must page-align\n");
3795 if (len
& (PAGE_SIZE
- 1)) {
3796 WARN_ONCE(1, "Ftrace: splice_read should page-align\n");
3797 if (len
< PAGE_SIZE
) {
3804 trace_access_lock(info
->cpu
);
3805 entries
= ring_buffer_entries_cpu(info
->tr
->buffer
, info
->cpu
);
3807 for (i
= 0; i
< pipe
->buffers
&& len
&& entries
; i
++, len
-= PAGE_SIZE
) {
3811 ref
= kzalloc(sizeof(*ref
), GFP_KERNEL
);
3816 ref
->buffer
= info
->tr
->buffer
;
3817 ref
->page
= ring_buffer_alloc_read_page(ref
->buffer
);
3823 r
= ring_buffer_read_page(ref
->buffer
, &ref
->page
,
3826 ring_buffer_free_read_page(ref
->buffer
,
3833 * zero out any left over data, this is going to
3836 size
= ring_buffer_page_len(ref
->page
);
3837 if (size
< PAGE_SIZE
)
3838 memset(ref
->page
+ size
, 0, PAGE_SIZE
- size
);
3840 page
= virt_to_page(ref
->page
);
3842 spd
.pages
[i
] = page
;
3843 spd
.partial
[i
].len
= PAGE_SIZE
;
3844 spd
.partial
[i
].offset
= 0;
3845 spd
.partial
[i
].private = (unsigned long)ref
;
3849 entries
= ring_buffer_entries_cpu(info
->tr
->buffer
, info
->cpu
);
3852 trace_access_unlock(info
->cpu
);
3855 /* did we read anything? */
3856 if (!spd
.nr_pages
) {
3857 if (flags
& SPLICE_F_NONBLOCK
)
3865 ret
= splice_to_pipe(pipe
, &spd
);
3866 splice_shrink_spd(pipe
, &spd
);
3871 static const struct file_operations tracing_buffers_fops
= {
3872 .open
= tracing_buffers_open
,
3873 .read
= tracing_buffers_read
,
3874 .release
= tracing_buffers_release
,
3875 .splice_read
= tracing_buffers_splice_read
,
3876 .llseek
= no_llseek
,
3880 tracing_stats_read(struct file
*filp
, char __user
*ubuf
,
3881 size_t count
, loff_t
*ppos
)
3883 unsigned long cpu
= (unsigned long)filp
->private_data
;
3884 struct trace_array
*tr
= &global_trace
;
3885 struct trace_seq
*s
;
3888 s
= kmalloc(sizeof(*s
), GFP_KERNEL
);
3894 cnt
= ring_buffer_entries_cpu(tr
->buffer
, cpu
);
3895 trace_seq_printf(s
, "entries: %ld\n", cnt
);
3897 cnt
= ring_buffer_overrun_cpu(tr
->buffer
, cpu
);
3898 trace_seq_printf(s
, "overrun: %ld\n", cnt
);
3900 cnt
= ring_buffer_commit_overrun_cpu(tr
->buffer
, cpu
);
3901 trace_seq_printf(s
, "commit overrun: %ld\n", cnt
);
3903 count
= simple_read_from_buffer(ubuf
, count
, ppos
, s
->buffer
, s
->len
);
3910 static const struct file_operations tracing_stats_fops
= {
3911 .open
= tracing_open_generic
,
3912 .read
= tracing_stats_read
,
3913 .llseek
= generic_file_llseek
,
3916 #ifdef CONFIG_DYNAMIC_FTRACE
3918 int __weak
ftrace_arch_read_dyn_info(char *buf
, int size
)
3924 tracing_read_dyn_info(struct file
*filp
, char __user
*ubuf
,
3925 size_t cnt
, loff_t
*ppos
)
3927 static char ftrace_dyn_info_buffer
[1024];
3928 static DEFINE_MUTEX(dyn_info_mutex
);
3929 unsigned long *p
= filp
->private_data
;
3930 char *buf
= ftrace_dyn_info_buffer
;
3931 int size
= ARRAY_SIZE(ftrace_dyn_info_buffer
);
3934 mutex_lock(&dyn_info_mutex
);
3935 r
= sprintf(buf
, "%ld ", *p
);
3937 r
+= ftrace_arch_read_dyn_info(buf
+r
, (size
-1)-r
);
3940 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3942 mutex_unlock(&dyn_info_mutex
);
3947 static const struct file_operations tracing_dyn_info_fops
= {
3948 .open
= tracing_open_generic
,
3949 .read
= tracing_read_dyn_info
,
3950 .llseek
= generic_file_llseek
,
3954 static struct dentry
*d_tracer
;
3956 struct dentry
*tracing_init_dentry(void)
3963 if (!debugfs_initialized())
3966 d_tracer
= debugfs_create_dir("tracing", NULL
);
3968 if (!d_tracer
&& !once
) {
3970 pr_warning("Could not create debugfs directory 'tracing'\n");
3977 static struct dentry
*d_percpu
;
3979 struct dentry
*tracing_dentry_percpu(void)
3982 struct dentry
*d_tracer
;
3987 d_tracer
= tracing_init_dentry();
3992 d_percpu
= debugfs_create_dir("per_cpu", d_tracer
);
3994 if (!d_percpu
&& !once
) {
3996 pr_warning("Could not create debugfs directory 'per_cpu'\n");
4003 static void tracing_init_debugfs_percpu(long cpu
)
4005 struct dentry
*d_percpu
= tracing_dentry_percpu();
4006 struct dentry
*d_cpu
;
4007 /* strlen(cpu) + MAX(log10(cpu)) + '\0' */
4010 if (cpu
> 999 || cpu
< 0)
4013 sprintf(cpu_dir
, "cpu%ld", cpu
);
4014 d_cpu
= debugfs_create_dir(cpu_dir
, d_percpu
);
4016 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir
);
4020 /* per cpu trace_pipe */
4021 trace_create_file("trace_pipe", 0444, d_cpu
,
4022 (void *) cpu
, &tracing_pipe_fops
);
4025 trace_create_file("trace", 0644, d_cpu
,
4026 (void *) cpu
, &tracing_fops
);
4028 trace_create_file("trace_pipe_raw", 0444, d_cpu
,
4029 (void *) cpu
, &tracing_buffers_fops
);
4031 trace_create_file("stats", 0444, d_cpu
,
4032 (void *) cpu
, &tracing_stats_fops
);
4035 #ifdef CONFIG_FTRACE_SELFTEST
4036 /* Let selftest have access to static functions in this file */
4037 #include "trace_selftest.c"
4040 struct trace_option_dentry
{
4041 struct tracer_opt
*opt
;
4042 struct tracer_flags
*flags
;
4043 struct dentry
*entry
;
4047 trace_options_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
4050 struct trace_option_dentry
*topt
= filp
->private_data
;
4053 if (topt
->flags
->val
& topt
->opt
->bit
)
4058 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
4062 trace_options_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
4065 struct trace_option_dentry
*topt
= filp
->private_data
;
4070 if (cnt
>= sizeof(buf
))
4073 if (copy_from_user(&buf
, ubuf
, cnt
))
4078 ret
= strict_strtoul(buf
, 10, &val
);
4082 if (val
!= 0 && val
!= 1)
4085 if (!!(topt
->flags
->val
& topt
->opt
->bit
) != val
) {
4086 mutex_lock(&trace_types_lock
);
4087 ret
= __set_tracer_option(current_trace
, topt
->flags
,
4089 mutex_unlock(&trace_types_lock
);
4100 static const struct file_operations trace_options_fops
= {
4101 .open
= tracing_open_generic
,
4102 .read
= trace_options_read
,
4103 .write
= trace_options_write
,
4104 .llseek
= generic_file_llseek
,
4108 trace_options_core_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
4111 long index
= (long)filp
->private_data
;
4114 if (trace_flags
& (1 << index
))
4119 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
4123 trace_options_core_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
4126 long index
= (long)filp
->private_data
;
4131 if (cnt
>= sizeof(buf
))
4134 if (copy_from_user(&buf
, ubuf
, cnt
))
4139 ret
= strict_strtoul(buf
, 10, &val
);
4143 if (val
!= 0 && val
!= 1)
4145 set_tracer_flags(1 << index
, val
);
4152 static const struct file_operations trace_options_core_fops
= {
4153 .open
= tracing_open_generic
,
4154 .read
= trace_options_core_read
,
4155 .write
= trace_options_core_write
,
4156 .llseek
= generic_file_llseek
,
4159 struct dentry
*trace_create_file(const char *name
,
4161 struct dentry
*parent
,
4163 const struct file_operations
*fops
)
4167 ret
= debugfs_create_file(name
, mode
, parent
, data
, fops
);
4169 pr_warning("Could not create debugfs '%s' entry\n", name
);
4175 static struct dentry
*trace_options_init_dentry(void)
4177 struct dentry
*d_tracer
;
4178 static struct dentry
*t_options
;
4183 d_tracer
= tracing_init_dentry();
4187 t_options
= debugfs_create_dir("options", d_tracer
);
4189 pr_warning("Could not create debugfs directory 'options'\n");
4197 create_trace_option_file(struct trace_option_dentry
*topt
,
4198 struct tracer_flags
*flags
,
4199 struct tracer_opt
*opt
)
4201 struct dentry
*t_options
;
4203 t_options
= trace_options_init_dentry();
4207 topt
->flags
= flags
;
4210 topt
->entry
= trace_create_file(opt
->name
, 0644, t_options
, topt
,
4211 &trace_options_fops
);
4215 static struct trace_option_dentry
*
4216 create_trace_option_files(struct tracer
*tracer
)
4218 struct trace_option_dentry
*topts
;
4219 struct tracer_flags
*flags
;
4220 struct tracer_opt
*opts
;
4226 flags
= tracer
->flags
;
4228 if (!flags
|| !flags
->opts
)
4233 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
4236 topts
= kcalloc(cnt
+ 1, sizeof(*topts
), GFP_KERNEL
);
4240 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
4241 create_trace_option_file(&topts
[cnt
], flags
,
4248 destroy_trace_option_files(struct trace_option_dentry
*topts
)
4255 for (cnt
= 0; topts
[cnt
].opt
; cnt
++) {
4256 if (topts
[cnt
].entry
)
4257 debugfs_remove(topts
[cnt
].entry
);
4263 static struct dentry
*
4264 create_trace_option_core_file(const char *option
, long index
)
4266 struct dentry
*t_options
;
4268 t_options
= trace_options_init_dentry();
4272 return trace_create_file(option
, 0644, t_options
, (void *)index
,
4273 &trace_options_core_fops
);
4276 static __init
void create_trace_options_dir(void)
4278 struct dentry
*t_options
;
4281 t_options
= trace_options_init_dentry();
4285 for (i
= 0; trace_options
[i
]; i
++)
4286 create_trace_option_core_file(trace_options
[i
], i
);
4289 static __init
int tracer_init_debugfs(void)
4291 struct dentry
*d_tracer
;
4294 trace_access_lock_init();
4296 d_tracer
= tracing_init_dentry();
4298 trace_create_file("tracing_enabled", 0644, d_tracer
,
4299 &global_trace
, &tracing_ctrl_fops
);
4301 trace_create_file("trace_options", 0644, d_tracer
,
4302 NULL
, &tracing_iter_fops
);
4304 trace_create_file("tracing_cpumask", 0644, d_tracer
,
4305 NULL
, &tracing_cpumask_fops
);
4307 trace_create_file("trace", 0644, d_tracer
,
4308 (void *) TRACE_PIPE_ALL_CPU
, &tracing_fops
);
4310 trace_create_file("available_tracers", 0444, d_tracer
,
4311 &global_trace
, &show_traces_fops
);
4313 trace_create_file("current_tracer", 0644, d_tracer
,
4314 &global_trace
, &set_tracer_fops
);
4316 #ifdef CONFIG_TRACER_MAX_TRACE
4317 trace_create_file("tracing_max_latency", 0644, d_tracer
,
4318 &tracing_max_latency
, &tracing_max_lat_fops
);
4321 trace_create_file("tracing_thresh", 0644, d_tracer
,
4322 &tracing_thresh
, &tracing_max_lat_fops
);
4324 trace_create_file("README", 0444, d_tracer
,
4325 NULL
, &tracing_readme_fops
);
4327 trace_create_file("trace_pipe", 0444, d_tracer
,
4328 (void *) TRACE_PIPE_ALL_CPU
, &tracing_pipe_fops
);
4330 trace_create_file("buffer_size_kb", 0644, d_tracer
,
4331 &global_trace
, &tracing_entries_fops
);
4333 trace_create_file("trace_marker", 0220, d_tracer
,
4334 NULL
, &tracing_mark_fops
);
4336 trace_create_file("saved_cmdlines", 0444, d_tracer
,
4337 NULL
, &tracing_saved_cmdlines_fops
);
4339 trace_create_file("trace_clock", 0644, d_tracer
, NULL
,
4342 #ifdef CONFIG_DYNAMIC_FTRACE
4343 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
4344 &ftrace_update_tot_cnt
, &tracing_dyn_info_fops
);
4347 create_trace_options_dir();
4349 for_each_tracing_cpu(cpu
)
4350 tracing_init_debugfs_percpu(cpu
);
4355 static int trace_panic_handler(struct notifier_block
*this,
4356 unsigned long event
, void *unused
)
4358 if (ftrace_dump_on_oops
)
4359 ftrace_dump(ftrace_dump_on_oops
);
4363 static struct notifier_block trace_panic_notifier
= {
4364 .notifier_call
= trace_panic_handler
,
4366 .priority
= 150 /* priority: INT_MAX >= x >= 0 */
4369 static int trace_die_handler(struct notifier_block
*self
,
4375 if (ftrace_dump_on_oops
)
4376 ftrace_dump(ftrace_dump_on_oops
);
4384 static struct notifier_block trace_die_notifier
= {
4385 .notifier_call
= trace_die_handler
,
4390 * printk is set to max of 1024, we really don't need it that big.
4391 * Nothing should be printing 1000 characters anyway.
4393 #define TRACE_MAX_PRINT 1000
4396 * Define here KERN_TRACE so that we have one place to modify
4397 * it if we decide to change what log level the ftrace dump
4400 #define KERN_TRACE KERN_EMERG
4403 trace_printk_seq(struct trace_seq
*s
)
4405 /* Probably should print a warning here. */
4409 /* should be zero ended, but we are paranoid. */
4410 s
->buffer
[s
->len
] = 0;
4412 printk(KERN_TRACE
"%s", s
->buffer
);
4417 void trace_init_global_iter(struct trace_iterator
*iter
)
4419 iter
->tr
= &global_trace
;
4420 iter
->trace
= current_trace
;
4421 iter
->cpu_file
= TRACE_PIPE_ALL_CPU
;
4425 __ftrace_dump(bool disable_tracing
, enum ftrace_dump_mode oops_dump_mode
)
4427 static arch_spinlock_t ftrace_dump_lock
=
4428 (arch_spinlock_t
)__ARCH_SPIN_LOCK_UNLOCKED
;
4429 /* use static because iter can be a bit big for the stack */
4430 static struct trace_iterator iter
;
4431 unsigned int old_userobj
;
4432 static int dump_ran
;
4433 unsigned long flags
;
4437 local_irq_save(flags
);
4438 arch_spin_lock(&ftrace_dump_lock
);
4446 if (disable_tracing
)
4449 trace_init_global_iter(&iter
);
4451 for_each_tracing_cpu(cpu
) {
4452 atomic_inc(&iter
.tr
->data
[cpu
]->disabled
);
4455 old_userobj
= trace_flags
& TRACE_ITER_SYM_USEROBJ
;
4457 /* don't look at user memory in panic mode */
4458 trace_flags
&= ~TRACE_ITER_SYM_USEROBJ
;
4460 /* Simulate the iterator */
4461 iter
.tr
= &global_trace
;
4462 iter
.trace
= current_trace
;
4464 switch (oops_dump_mode
) {
4466 iter
.cpu_file
= TRACE_PIPE_ALL_CPU
;
4469 iter
.cpu_file
= raw_smp_processor_id();
4474 printk(KERN_TRACE
"Bad dumping mode, switching to all CPUs dump\n");
4475 iter
.cpu_file
= TRACE_PIPE_ALL_CPU
;
4478 printk(KERN_TRACE
"Dumping ftrace buffer:\n");
4481 * We need to stop all tracing on all CPUS to read the
4482 * the next buffer. This is a bit expensive, but is
4483 * not done often. We fill all what we can read,
4484 * and then release the locks again.
4487 while (!trace_empty(&iter
)) {
4490 printk(KERN_TRACE
"---------------------------------\n");
4494 /* reset all but tr, trace, and overruns */
4495 memset(&iter
.seq
, 0,
4496 sizeof(struct trace_iterator
) -
4497 offsetof(struct trace_iterator
, seq
));
4498 iter
.iter_flags
|= TRACE_FILE_LAT_FMT
;
4501 if (trace_find_next_entry_inc(&iter
) != NULL
) {
4504 ret
= print_trace_line(&iter
);
4505 if (ret
!= TRACE_TYPE_NO_CONSUME
)
4506 trace_consume(&iter
);
4509 trace_printk_seq(&iter
.seq
);
4513 printk(KERN_TRACE
" (ftrace buffer empty)\n");
4515 printk(KERN_TRACE
"---------------------------------\n");
4518 /* Re-enable tracing if requested */
4519 if (!disable_tracing
) {
4520 trace_flags
|= old_userobj
;
4522 for_each_tracing_cpu(cpu
) {
4523 atomic_dec(&iter
.tr
->data
[cpu
]->disabled
);
4529 arch_spin_unlock(&ftrace_dump_lock
);
4530 local_irq_restore(flags
);
4533 /* By default: disable tracing after the dump */
4534 void ftrace_dump(enum ftrace_dump_mode oops_dump_mode
)
4536 __ftrace_dump(true, oops_dump_mode
);
4539 __init
static int tracer_alloc_buffers(void)
4545 if (!alloc_cpumask_var(&tracing_buffer_mask
, GFP_KERNEL
))
4548 if (!alloc_cpumask_var(&tracing_cpumask
, GFP_KERNEL
))
4549 goto out_free_buffer_mask
;
4551 /* To save memory, keep the ring buffer size to its minimum */
4552 if (ring_buffer_expanded
)
4553 ring_buf_size
= trace_buf_size
;
4557 cpumask_copy(tracing_buffer_mask
, cpu_possible_mask
);
4558 cpumask_copy(tracing_cpumask
, cpu_all_mask
);
4560 /* TODO: make the number of buffers hot pluggable with CPUS */
4561 global_trace
.buffer
= ring_buffer_alloc(ring_buf_size
,
4562 TRACE_BUFFER_FLAGS
);
4563 if (!global_trace
.buffer
) {
4564 printk(KERN_ERR
"tracer: failed to allocate ring buffer!\n");
4566 goto out_free_cpumask
;
4568 global_trace
.entries
= ring_buffer_size(global_trace
.buffer
);
4571 #ifdef CONFIG_TRACER_MAX_TRACE
4572 max_tr
.buffer
= ring_buffer_alloc(1, TRACE_BUFFER_FLAGS
);
4573 if (!max_tr
.buffer
) {
4574 printk(KERN_ERR
"tracer: failed to allocate max ring buffer!\n");
4576 ring_buffer_free(global_trace
.buffer
);
4577 goto out_free_cpumask
;
4582 /* Allocate the first page for all buffers */
4583 for_each_tracing_cpu(i
) {
4584 global_trace
.data
[i
] = &per_cpu(global_trace_cpu
, i
);
4585 max_tr
.data
[i
] = &per_cpu(max_tr_data
, i
);
4588 trace_init_cmdlines();
4590 register_tracer(&nop_trace
);
4591 current_trace
= &nop_trace
;
4592 /* All seems OK, enable tracing */
4593 tracing_disabled
= 0;
4595 atomic_notifier_chain_register(&panic_notifier_list
,
4596 &trace_panic_notifier
);
4598 register_die_notifier(&trace_die_notifier
);
4603 free_cpumask_var(tracing_cpumask
);
4604 out_free_buffer_mask
:
4605 free_cpumask_var(tracing_buffer_mask
);
4610 __init
static int clear_boot_tracer(void)
4613 * The default tracer at boot buffer is an init section.
4614 * This function is called in lateinit. If we did not
4615 * find the boot tracer, then clear it out, to prevent
4616 * later registration from accessing the buffer that is
4617 * about to be freed.
4619 if (!default_bootup_tracer
)
4622 printk(KERN_INFO
"ftrace bootup tracer '%s' not registered.\n",
4623 default_bootup_tracer
);
4624 default_bootup_tracer
= NULL
;
4629 early_initcall(tracer_alloc_buffers
);
4630 fs_initcall(tracer_init_debugfs
);
4631 late_initcall(clear_boot_tracer
);