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
);
745 * When this gets called we hold the BKL which means that
746 * preemption is disabled. Various trace selftests however
747 * need to disable and enable preemption for successful tests.
748 * So we drop the BKL here and grab it after the tests again.
751 mutex_lock(&trace_types_lock
);
753 tracing_selftest_running
= true;
755 for (t
= trace_types
; t
; t
= t
->next
) {
756 if (strcmp(type
->name
, t
->name
) == 0) {
758 pr_info("Tracer %s already registered\n",
766 type
->set_flag
= &dummy_set_flag
;
768 type
->flags
= &dummy_tracer_flags
;
770 if (!type
->flags
->opts
)
771 type
->flags
->opts
= dummy_tracer_opt
;
772 if (!type
->wait_pipe
)
773 type
->wait_pipe
= default_wait_pipe
;
776 #ifdef CONFIG_FTRACE_STARTUP_TEST
777 if (type
->selftest
&& !tracing_selftest_disabled
) {
778 struct tracer
*saved_tracer
= current_trace
;
779 struct trace_array
*tr
= &global_trace
;
782 * Run a selftest on this tracer.
783 * Here we reset the trace buffer, and set the current
784 * tracer to be this tracer. The tracer can then run some
785 * internal tracing to verify that everything is in order.
786 * If we fail, we do not register this tracer.
788 tracing_reset_online_cpus(tr
);
790 current_trace
= type
;
791 /* the test is responsible for initializing and enabling */
792 pr_info("Testing tracer %s: ", type
->name
);
793 ret
= type
->selftest(type
, tr
);
794 /* the test is responsible for resetting too */
795 current_trace
= saved_tracer
;
797 printk(KERN_CONT
"FAILED!\n");
800 /* Only reset on passing, to avoid touching corrupted buffers */
801 tracing_reset_online_cpus(tr
);
803 printk(KERN_CONT
"PASSED\n");
807 type
->next
= trace_types
;
811 tracing_selftest_running
= false;
812 mutex_unlock(&trace_types_lock
);
814 if (ret
|| !default_bootup_tracer
)
817 if (strncmp(default_bootup_tracer
, type
->name
, MAX_TRACER_SIZE
))
820 printk(KERN_INFO
"Starting tracer '%s'\n", type
->name
);
821 /* Do we want this tracer to start on bootup? */
822 tracing_set_tracer(type
->name
);
823 default_bootup_tracer
= NULL
;
824 /* disable other selftests, since this will break it. */
825 tracing_selftest_disabled
= 1;
826 #ifdef CONFIG_FTRACE_STARTUP_TEST
827 printk(KERN_INFO
"Disabling FTRACE selftests due to running tracer '%s'\n",
836 void unregister_tracer(struct tracer
*type
)
840 mutex_lock(&trace_types_lock
);
841 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
845 pr_info("Tracer %s not registered\n", type
->name
);
851 if (type
== current_trace
&& tracer_enabled
) {
854 if (current_trace
->stop
)
855 current_trace
->stop(&global_trace
);
856 current_trace
= &nop_trace
;
859 mutex_unlock(&trace_types_lock
);
862 static void __tracing_reset(struct ring_buffer
*buffer
, int cpu
)
864 ftrace_disable_cpu();
865 ring_buffer_reset_cpu(buffer
, cpu
);
869 void tracing_reset(struct trace_array
*tr
, int cpu
)
871 struct ring_buffer
*buffer
= tr
->buffer
;
873 ring_buffer_record_disable(buffer
);
875 /* Make sure all commits have finished */
877 __tracing_reset(buffer
, cpu
);
879 ring_buffer_record_enable(buffer
);
882 void tracing_reset_online_cpus(struct trace_array
*tr
)
884 struct ring_buffer
*buffer
= tr
->buffer
;
887 ring_buffer_record_disable(buffer
);
889 /* Make sure all commits have finished */
892 tr
->time_start
= ftrace_now(tr
->cpu
);
894 for_each_online_cpu(cpu
)
895 __tracing_reset(buffer
, cpu
);
897 ring_buffer_record_enable(buffer
);
900 void tracing_reset_current(int cpu
)
902 tracing_reset(&global_trace
, cpu
);
905 void tracing_reset_current_online_cpus(void)
907 tracing_reset_online_cpus(&global_trace
);
910 #define SAVED_CMDLINES 128
911 #define NO_CMDLINE_MAP UINT_MAX
912 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
913 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
914 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
915 static int cmdline_idx
;
916 static arch_spinlock_t trace_cmdline_lock
= __ARCH_SPIN_LOCK_UNLOCKED
;
918 /* temporary disable recording */
919 static atomic_t trace_record_cmdline_disabled __read_mostly
;
921 static void trace_init_cmdlines(void)
923 memset(&map_pid_to_cmdline
, NO_CMDLINE_MAP
, sizeof(map_pid_to_cmdline
));
924 memset(&map_cmdline_to_pid
, NO_CMDLINE_MAP
, sizeof(map_cmdline_to_pid
));
928 int is_tracing_stopped(void)
930 return trace_stop_count
;
934 * ftrace_off_permanent - disable all ftrace code permanently
936 * This should only be called when a serious anomally has
937 * been detected. This will turn off the function tracing,
938 * ring buffers, and other tracing utilites. It takes no
939 * locks and can be called from any context.
941 void ftrace_off_permanent(void)
943 tracing_disabled
= 1;
945 tracing_off_permanent();
949 * tracing_start - quick start of the tracer
951 * If tracing is enabled but was stopped by tracing_stop,
952 * this will start the tracer back up.
954 void tracing_start(void)
956 struct ring_buffer
*buffer
;
959 if (tracing_disabled
)
962 spin_lock_irqsave(&tracing_start_lock
, flags
);
963 if (--trace_stop_count
) {
964 if (trace_stop_count
< 0) {
965 /* Someone screwed up their debugging */
967 trace_stop_count
= 0;
972 /* Prevent the buffers from switching */
973 arch_spin_lock(&ftrace_max_lock
);
975 buffer
= global_trace
.buffer
;
977 ring_buffer_record_enable(buffer
);
979 buffer
= max_tr
.buffer
;
981 ring_buffer_record_enable(buffer
);
983 arch_spin_unlock(&ftrace_max_lock
);
987 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
991 * tracing_stop - quick stop of the tracer
993 * Light weight way to stop tracing. Use in conjunction with
996 void tracing_stop(void)
998 struct ring_buffer
*buffer
;
1002 spin_lock_irqsave(&tracing_start_lock
, flags
);
1003 if (trace_stop_count
++)
1006 /* Prevent the buffers from switching */
1007 arch_spin_lock(&ftrace_max_lock
);
1009 buffer
= global_trace
.buffer
;
1011 ring_buffer_record_disable(buffer
);
1013 buffer
= max_tr
.buffer
;
1015 ring_buffer_record_disable(buffer
);
1017 arch_spin_unlock(&ftrace_max_lock
);
1020 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
1023 void trace_stop_cmdline_recording(void);
1025 static void trace_save_cmdline(struct task_struct
*tsk
)
1029 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
1033 * It's not the end of the world if we don't get
1034 * the lock, but we also don't want to spin
1035 * nor do we want to disable interrupts,
1036 * so if we miss here, then better luck next time.
1038 if (!arch_spin_trylock(&trace_cmdline_lock
))
1041 idx
= map_pid_to_cmdline
[tsk
->pid
];
1042 if (idx
== NO_CMDLINE_MAP
) {
1043 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
1046 * Check whether the cmdline buffer at idx has a pid
1047 * mapped. We are going to overwrite that entry so we
1048 * need to clear the map_pid_to_cmdline. Otherwise we
1049 * would read the new comm for the old pid.
1051 pid
= map_cmdline_to_pid
[idx
];
1052 if (pid
!= NO_CMDLINE_MAP
)
1053 map_pid_to_cmdline
[pid
] = NO_CMDLINE_MAP
;
1055 map_cmdline_to_pid
[idx
] = tsk
->pid
;
1056 map_pid_to_cmdline
[tsk
->pid
] = idx
;
1061 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
1063 arch_spin_unlock(&trace_cmdline_lock
);
1066 void trace_find_cmdline(int pid
, char comm
[])
1071 strcpy(comm
, "<idle>");
1075 if (WARN_ON_ONCE(pid
< 0)) {
1076 strcpy(comm
, "<XXX>");
1080 if (pid
> PID_MAX_DEFAULT
) {
1081 strcpy(comm
, "<...>");
1086 arch_spin_lock(&trace_cmdline_lock
);
1087 map
= map_pid_to_cmdline
[pid
];
1088 if (map
!= NO_CMDLINE_MAP
)
1089 strcpy(comm
, saved_cmdlines
[map
]);
1091 strcpy(comm
, "<...>");
1093 arch_spin_unlock(&trace_cmdline_lock
);
1097 void tracing_record_cmdline(struct task_struct
*tsk
)
1099 if (atomic_read(&trace_record_cmdline_disabled
) || !tracer_enabled
||
1103 trace_save_cmdline(tsk
);
1107 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
,
1110 struct task_struct
*tsk
= current
;
1112 entry
->preempt_count
= pc
& 0xff;
1113 entry
->pid
= (tsk
) ? tsk
->pid
: 0;
1114 entry
->lock_depth
= (tsk
) ? tsk
->lock_depth
: 0;
1116 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1117 (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
1119 TRACE_FLAG_IRQS_NOSUPPORT
|
1121 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
1122 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
1123 (need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0);
1125 EXPORT_SYMBOL_GPL(tracing_generic_entry_update
);
1127 struct ring_buffer_event
*
1128 trace_buffer_lock_reserve(struct ring_buffer
*buffer
,
1131 unsigned long flags
, int pc
)
1133 struct ring_buffer_event
*event
;
1135 event
= ring_buffer_lock_reserve(buffer
, len
);
1136 if (event
!= NULL
) {
1137 struct trace_entry
*ent
= ring_buffer_event_data(event
);
1139 tracing_generic_entry_update(ent
, flags
, pc
);
1147 __trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1148 struct ring_buffer_event
*event
,
1149 unsigned long flags
, int pc
,
1152 ring_buffer_unlock_commit(buffer
, event
);
1154 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1155 ftrace_trace_userstack(buffer
, flags
, pc
);
1161 void trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1162 struct ring_buffer_event
*event
,
1163 unsigned long flags
, int pc
)
1165 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
, 1);
1168 struct ring_buffer_event
*
1169 trace_current_buffer_lock_reserve(struct ring_buffer
**current_rb
,
1170 int type
, unsigned long len
,
1171 unsigned long flags
, int pc
)
1173 *current_rb
= global_trace
.buffer
;
1174 return trace_buffer_lock_reserve(*current_rb
,
1175 type
, len
, flags
, pc
);
1177 EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve
);
1179 void trace_current_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
, 1);
1185 EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit
);
1187 void trace_nowake_buffer_unlock_commit(struct ring_buffer
*buffer
,
1188 struct ring_buffer_event
*event
,
1189 unsigned long flags
, int pc
)
1191 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
, 0);
1193 EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit
);
1195 void trace_current_buffer_discard_commit(struct ring_buffer
*buffer
,
1196 struct ring_buffer_event
*event
)
1198 ring_buffer_discard_commit(buffer
, event
);
1200 EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit
);
1203 trace_function(struct trace_array
*tr
,
1204 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
1207 struct ftrace_event_call
*call
= &event_function
;
1208 struct ring_buffer
*buffer
= tr
->buffer
;
1209 struct ring_buffer_event
*event
;
1210 struct ftrace_entry
*entry
;
1212 /* If we are reading the ring buffer, don't trace */
1213 if (unlikely(__this_cpu_read(ftrace_cpu_disabled
)))
1216 event
= trace_buffer_lock_reserve(buffer
, TRACE_FN
, sizeof(*entry
),
1220 entry
= ring_buffer_event_data(event
);
1222 entry
->parent_ip
= parent_ip
;
1224 if (!filter_check_discard(call
, entry
, buffer
, event
))
1225 ring_buffer_unlock_commit(buffer
, event
);
1229 ftrace(struct trace_array
*tr
, struct trace_array_cpu
*data
,
1230 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
1233 if (likely(!atomic_read(&data
->disabled
)))
1234 trace_function(tr
, ip
, parent_ip
, flags
, pc
);
1237 #ifdef CONFIG_STACKTRACE
1238 static void __ftrace_trace_stack(struct ring_buffer
*buffer
,
1239 unsigned long flags
,
1242 struct ftrace_event_call
*call
= &event_kernel_stack
;
1243 struct ring_buffer_event
*event
;
1244 struct stack_entry
*entry
;
1245 struct stack_trace trace
;
1247 event
= trace_buffer_lock_reserve(buffer
, TRACE_STACK
,
1248 sizeof(*entry
), flags
, pc
);
1251 entry
= ring_buffer_event_data(event
);
1252 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
1254 trace
.nr_entries
= 0;
1255 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1257 trace
.entries
= entry
->caller
;
1259 save_stack_trace(&trace
);
1260 if (!filter_check_discard(call
, entry
, buffer
, event
))
1261 ring_buffer_unlock_commit(buffer
, event
);
1264 void ftrace_trace_stack(struct ring_buffer
*buffer
, unsigned long flags
,
1267 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1270 __ftrace_trace_stack(buffer
, flags
, skip
, pc
);
1273 void __trace_stack(struct trace_array
*tr
, unsigned long flags
, int skip
,
1276 __ftrace_trace_stack(tr
->buffer
, flags
, skip
, pc
);
1280 * trace_dump_stack - record a stack back trace in the trace buffer
1282 void trace_dump_stack(void)
1284 unsigned long flags
;
1286 if (tracing_disabled
|| tracing_selftest_running
)
1289 local_save_flags(flags
);
1291 /* skipping 3 traces, seems to get us at the caller of this function */
1292 __ftrace_trace_stack(global_trace
.buffer
, flags
, 3, preempt_count());
1296 ftrace_trace_userstack(struct ring_buffer
*buffer
, unsigned long flags
, int pc
)
1298 struct ftrace_event_call
*call
= &event_user_stack
;
1299 struct ring_buffer_event
*event
;
1300 struct userstack_entry
*entry
;
1301 struct stack_trace trace
;
1303 if (!(trace_flags
& TRACE_ITER_USERSTACKTRACE
))
1307 * NMIs can not handle page faults, even with fix ups.
1308 * The save user stack can (and often does) fault.
1310 if (unlikely(in_nmi()))
1313 event
= trace_buffer_lock_reserve(buffer
, TRACE_USER_STACK
,
1314 sizeof(*entry
), flags
, pc
);
1317 entry
= ring_buffer_event_data(event
);
1319 entry
->tgid
= current
->tgid
;
1320 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
1322 trace
.nr_entries
= 0;
1323 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1325 trace
.entries
= entry
->caller
;
1327 save_stack_trace_user(&trace
);
1328 if (!filter_check_discard(call
, entry
, buffer
, event
))
1329 ring_buffer_unlock_commit(buffer
, event
);
1333 static void __trace_userstack(struct trace_array
*tr
, unsigned long flags
)
1335 ftrace_trace_userstack(tr
, flags
, preempt_count());
1339 #endif /* CONFIG_STACKTRACE */
1342 * trace_vbprintk - write binary msg to tracing buffer
1345 int trace_vbprintk(unsigned long ip
, const char *fmt
, va_list args
)
1347 static arch_spinlock_t trace_buf_lock
=
1348 (arch_spinlock_t
)__ARCH_SPIN_LOCK_UNLOCKED
;
1349 static u32 trace_buf
[TRACE_BUF_SIZE
];
1351 struct ftrace_event_call
*call
= &event_bprint
;
1352 struct ring_buffer_event
*event
;
1353 struct ring_buffer
*buffer
;
1354 struct trace_array
*tr
= &global_trace
;
1355 struct trace_array_cpu
*data
;
1356 struct bprint_entry
*entry
;
1357 unsigned long flags
;
1359 int cpu
, len
= 0, size
, pc
;
1361 if (unlikely(tracing_selftest_running
|| tracing_disabled
))
1364 /* Don't pollute graph traces with trace_vprintk internals */
1365 pause_graph_tracing();
1367 pc
= preempt_count();
1368 preempt_disable_notrace();
1369 cpu
= raw_smp_processor_id();
1370 data
= tr
->data
[cpu
];
1372 disable
= atomic_inc_return(&data
->disabled
);
1373 if (unlikely(disable
!= 1))
1376 /* Lockdep uses trace_printk for lock tracing */
1377 local_irq_save(flags
);
1378 arch_spin_lock(&trace_buf_lock
);
1379 len
= vbin_printf(trace_buf
, TRACE_BUF_SIZE
, fmt
, args
);
1381 if (len
> TRACE_BUF_SIZE
|| len
< 0)
1384 size
= sizeof(*entry
) + sizeof(u32
) * len
;
1385 buffer
= tr
->buffer
;
1386 event
= trace_buffer_lock_reserve(buffer
, TRACE_BPRINT
, size
,
1390 entry
= ring_buffer_event_data(event
);
1394 memcpy(entry
->buf
, trace_buf
, sizeof(u32
) * len
);
1395 if (!filter_check_discard(call
, entry
, buffer
, event
)) {
1396 ring_buffer_unlock_commit(buffer
, event
);
1397 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1401 arch_spin_unlock(&trace_buf_lock
);
1402 local_irq_restore(flags
);
1405 atomic_dec_return(&data
->disabled
);
1406 preempt_enable_notrace();
1407 unpause_graph_tracing();
1411 EXPORT_SYMBOL_GPL(trace_vbprintk
);
1413 int trace_array_printk(struct trace_array
*tr
,
1414 unsigned long ip
, const char *fmt
, ...)
1419 if (!(trace_flags
& TRACE_ITER_PRINTK
))
1423 ret
= trace_array_vprintk(tr
, ip
, fmt
, ap
);
1428 int trace_array_vprintk(struct trace_array
*tr
,
1429 unsigned long ip
, const char *fmt
, va_list args
)
1431 static arch_spinlock_t trace_buf_lock
= __ARCH_SPIN_LOCK_UNLOCKED
;
1432 static char trace_buf
[TRACE_BUF_SIZE
];
1434 struct ftrace_event_call
*call
= &event_print
;
1435 struct ring_buffer_event
*event
;
1436 struct ring_buffer
*buffer
;
1437 struct trace_array_cpu
*data
;
1438 int cpu
, len
= 0, size
, pc
;
1439 struct print_entry
*entry
;
1440 unsigned long irq_flags
;
1443 if (tracing_disabled
|| tracing_selftest_running
)
1446 pc
= preempt_count();
1447 preempt_disable_notrace();
1448 cpu
= raw_smp_processor_id();
1449 data
= tr
->data
[cpu
];
1451 disable
= atomic_inc_return(&data
->disabled
);
1452 if (unlikely(disable
!= 1))
1455 pause_graph_tracing();
1456 raw_local_irq_save(irq_flags
);
1457 arch_spin_lock(&trace_buf_lock
);
1458 len
= vsnprintf(trace_buf
, TRACE_BUF_SIZE
, fmt
, args
);
1460 size
= sizeof(*entry
) + len
+ 1;
1461 buffer
= tr
->buffer
;
1462 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, size
,
1466 entry
= ring_buffer_event_data(event
);
1469 memcpy(&entry
->buf
, trace_buf
, len
);
1470 entry
->buf
[len
] = '\0';
1471 if (!filter_check_discard(call
, entry
, buffer
, event
)) {
1472 ring_buffer_unlock_commit(buffer
, event
);
1473 ftrace_trace_stack(buffer
, irq_flags
, 6, pc
);
1477 arch_spin_unlock(&trace_buf_lock
);
1478 raw_local_irq_restore(irq_flags
);
1479 unpause_graph_tracing();
1481 atomic_dec_return(&data
->disabled
);
1482 preempt_enable_notrace();
1487 int trace_vprintk(unsigned long ip
, const char *fmt
, va_list args
)
1489 return trace_array_vprintk(&global_trace
, ip
, fmt
, args
);
1491 EXPORT_SYMBOL_GPL(trace_vprintk
);
1493 static void trace_iterator_increment(struct trace_iterator
*iter
)
1495 /* Don't allow ftrace to trace into the ring buffers */
1496 ftrace_disable_cpu();
1499 if (iter
->buffer_iter
[iter
->cpu
])
1500 ring_buffer_read(iter
->buffer_iter
[iter
->cpu
], NULL
);
1502 ftrace_enable_cpu();
1505 static struct trace_entry
*
1506 peek_next_entry(struct trace_iterator
*iter
, int cpu
, u64
*ts
,
1507 unsigned long *lost_events
)
1509 struct ring_buffer_event
*event
;
1510 struct ring_buffer_iter
*buf_iter
= iter
->buffer_iter
[cpu
];
1512 /* Don't allow ftrace to trace into the ring buffers */
1513 ftrace_disable_cpu();
1516 event
= ring_buffer_iter_peek(buf_iter
, ts
);
1518 event
= ring_buffer_peek(iter
->tr
->buffer
, cpu
, ts
,
1521 ftrace_enable_cpu();
1523 return event
? ring_buffer_event_data(event
) : NULL
;
1526 static struct trace_entry
*
1527 __find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
,
1528 unsigned long *missing_events
, u64
*ent_ts
)
1530 struct ring_buffer
*buffer
= iter
->tr
->buffer
;
1531 struct trace_entry
*ent
, *next
= NULL
;
1532 unsigned long lost_events
= 0, next_lost
= 0;
1533 int cpu_file
= iter
->cpu_file
;
1534 u64 next_ts
= 0, ts
;
1539 * If we are in a per_cpu trace file, don't bother by iterating over
1540 * all cpu and peek directly.
1542 if (cpu_file
> TRACE_PIPE_ALL_CPU
) {
1543 if (ring_buffer_empty_cpu(buffer
, cpu_file
))
1545 ent
= peek_next_entry(iter
, cpu_file
, ent_ts
, missing_events
);
1547 *ent_cpu
= cpu_file
;
1552 for_each_tracing_cpu(cpu
) {
1554 if (ring_buffer_empty_cpu(buffer
, cpu
))
1557 ent
= peek_next_entry(iter
, cpu
, &ts
, &lost_events
);
1560 * Pick the entry with the smallest timestamp:
1562 if (ent
&& (!next
|| ts
< next_ts
)) {
1566 next_lost
= lost_events
;
1571 *ent_cpu
= next_cpu
;
1577 *missing_events
= next_lost
;
1582 /* Find the next real entry, without updating the iterator itself */
1583 struct trace_entry
*trace_find_next_entry(struct trace_iterator
*iter
,
1584 int *ent_cpu
, u64
*ent_ts
)
1586 return __find_next_entry(iter
, ent_cpu
, NULL
, ent_ts
);
1589 /* Find the next real entry, and increment the iterator to the next entry */
1590 void *trace_find_next_entry_inc(struct trace_iterator
*iter
)
1592 iter
->ent
= __find_next_entry(iter
, &iter
->cpu
,
1593 &iter
->lost_events
, &iter
->ts
);
1596 trace_iterator_increment(iter
);
1598 return iter
->ent
? iter
: NULL
;
1601 static void trace_consume(struct trace_iterator
*iter
)
1603 /* Don't allow ftrace to trace into the ring buffers */
1604 ftrace_disable_cpu();
1605 ring_buffer_consume(iter
->tr
->buffer
, iter
->cpu
, &iter
->ts
,
1606 &iter
->lost_events
);
1607 ftrace_enable_cpu();
1610 static void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1612 struct trace_iterator
*iter
= m
->private;
1616 WARN_ON_ONCE(iter
->leftover
);
1620 /* can't go backwards */
1625 ent
= trace_find_next_entry_inc(iter
);
1629 while (ent
&& iter
->idx
< i
)
1630 ent
= trace_find_next_entry_inc(iter
);
1637 void tracing_iter_reset(struct trace_iterator
*iter
, int cpu
)
1639 struct trace_array
*tr
= iter
->tr
;
1640 struct ring_buffer_event
*event
;
1641 struct ring_buffer_iter
*buf_iter
;
1642 unsigned long entries
= 0;
1645 tr
->data
[cpu
]->skipped_entries
= 0;
1647 if (!iter
->buffer_iter
[cpu
])
1650 buf_iter
= iter
->buffer_iter
[cpu
];
1651 ring_buffer_iter_reset(buf_iter
);
1654 * We could have the case with the max latency tracers
1655 * that a reset never took place on a cpu. This is evident
1656 * by the timestamp being before the start of the buffer.
1658 while ((event
= ring_buffer_iter_peek(buf_iter
, &ts
))) {
1659 if (ts
>= iter
->tr
->time_start
)
1662 ring_buffer_read(buf_iter
, NULL
);
1665 tr
->data
[cpu
]->skipped_entries
= entries
;
1669 * The current tracer is copied to avoid a global locking
1672 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
1674 struct trace_iterator
*iter
= m
->private;
1675 static struct tracer
*old_tracer
;
1676 int cpu_file
= iter
->cpu_file
;
1681 /* copy the tracer to avoid using a global lock all around */
1682 mutex_lock(&trace_types_lock
);
1683 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
1684 old_tracer
= current_trace
;
1685 *iter
->trace
= *current_trace
;
1687 mutex_unlock(&trace_types_lock
);
1689 atomic_inc(&trace_record_cmdline_disabled
);
1691 if (*pos
!= iter
->pos
) {
1696 ftrace_disable_cpu();
1698 if (cpu_file
== TRACE_PIPE_ALL_CPU
) {
1699 for_each_tracing_cpu(cpu
)
1700 tracing_iter_reset(iter
, cpu
);
1702 tracing_iter_reset(iter
, cpu_file
);
1704 ftrace_enable_cpu();
1707 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
1712 * If we overflowed the seq_file before, then we want
1713 * to just reuse the trace_seq buffer again.
1719 p
= s_next(m
, p
, &l
);
1723 trace_event_read_lock();
1724 trace_access_lock(cpu_file
);
1728 static void s_stop(struct seq_file
*m
, void *p
)
1730 struct trace_iterator
*iter
= m
->private;
1732 atomic_dec(&trace_record_cmdline_disabled
);
1733 trace_access_unlock(iter
->cpu_file
);
1734 trace_event_read_unlock();
1737 static void print_lat_help_header(struct seq_file
*m
)
1739 seq_puts(m
, "# _------=> CPU# \n");
1740 seq_puts(m
, "# / _-----=> irqs-off \n");
1741 seq_puts(m
, "# | / _----=> need-resched \n");
1742 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
1743 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
1744 seq_puts(m
, "# |||| /_--=> lock-depth \n");
1745 seq_puts(m
, "# |||||/ delay \n");
1746 seq_puts(m
, "# cmd pid |||||| time | caller \n");
1747 seq_puts(m
, "# \\ / |||||| \\ | / \n");
1750 static void print_func_help_header(struct seq_file
*m
)
1752 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1753 seq_puts(m
, "# | | | | |\n");
1758 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
1760 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1761 struct trace_array
*tr
= iter
->tr
;
1762 struct trace_array_cpu
*data
= tr
->data
[tr
->cpu
];
1763 struct tracer
*type
= current_trace
;
1764 unsigned long entries
= 0;
1765 unsigned long total
= 0;
1766 unsigned long count
;
1767 const char *name
= "preemption";
1774 for_each_tracing_cpu(cpu
) {
1775 count
= ring_buffer_entries_cpu(tr
->buffer
, cpu
);
1777 * If this buffer has skipped entries, then we hold all
1778 * entries for the trace and we need to ignore the
1779 * ones before the time stamp.
1781 if (tr
->data
[cpu
]->skipped_entries
) {
1782 count
-= tr
->data
[cpu
]->skipped_entries
;
1783 /* total is the same as the entries */
1787 ring_buffer_overrun_cpu(tr
->buffer
, cpu
);
1791 seq_printf(m
, "# %s latency trace v1.1.5 on %s\n",
1793 seq_puts(m
, "# -----------------------------------"
1794 "---------------------------------\n");
1795 seq_printf(m
, "# latency: %lu us, #%lu/%lu, CPU#%d |"
1796 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1797 nsecs_to_usecs(data
->saved_latency
),
1801 #if defined(CONFIG_PREEMPT_NONE)
1803 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1805 #elif defined(CONFIG_PREEMPT)
1810 /* These are reserved for later use */
1813 seq_printf(m
, " #P:%d)\n", num_online_cpus());
1817 seq_puts(m
, "# -----------------\n");
1818 seq_printf(m
, "# | task: %.16s-%d "
1819 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1820 data
->comm
, data
->pid
, data
->uid
, data
->nice
,
1821 data
->policy
, data
->rt_priority
);
1822 seq_puts(m
, "# -----------------\n");
1824 if (data
->critical_start
) {
1825 seq_puts(m
, "# => started at: ");
1826 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
1827 trace_print_seq(m
, &iter
->seq
);
1828 seq_puts(m
, "\n# => ended at: ");
1829 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
1830 trace_print_seq(m
, &iter
->seq
);
1831 seq_puts(m
, "\n#\n");
1837 static void test_cpu_buff_start(struct trace_iterator
*iter
)
1839 struct trace_seq
*s
= &iter
->seq
;
1841 if (!(trace_flags
& TRACE_ITER_ANNOTATE
))
1844 if (!(iter
->iter_flags
& TRACE_FILE_ANNOTATE
))
1847 if (cpumask_test_cpu(iter
->cpu
, iter
->started
))
1850 if (iter
->tr
->data
[iter
->cpu
]->skipped_entries
)
1853 cpumask_set_cpu(iter
->cpu
, iter
->started
);
1855 /* Don't print started cpu buffer for the first entry of the trace */
1857 trace_seq_printf(s
, "##### CPU %u buffer started ####\n",
1861 static enum print_line_t
print_trace_fmt(struct trace_iterator
*iter
)
1863 struct trace_seq
*s
= &iter
->seq
;
1864 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1865 struct trace_entry
*entry
;
1866 struct trace_event
*event
;
1870 test_cpu_buff_start(iter
);
1872 event
= ftrace_find_event(entry
->type
);
1874 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1875 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
1876 if (!trace_print_lat_context(iter
))
1879 if (!trace_print_context(iter
))
1885 return event
->funcs
->trace(iter
, sym_flags
, event
);
1887 if (!trace_seq_printf(s
, "Unknown type %d\n", entry
->type
))
1890 return TRACE_TYPE_HANDLED
;
1892 return TRACE_TYPE_PARTIAL_LINE
;
1895 static enum print_line_t
print_raw_fmt(struct trace_iterator
*iter
)
1897 struct trace_seq
*s
= &iter
->seq
;
1898 struct trace_entry
*entry
;
1899 struct trace_event
*event
;
1903 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1904 if (!trace_seq_printf(s
, "%d %d %llu ",
1905 entry
->pid
, iter
->cpu
, iter
->ts
))
1909 event
= ftrace_find_event(entry
->type
);
1911 return event
->funcs
->raw(iter
, 0, event
);
1913 if (!trace_seq_printf(s
, "%d ?\n", entry
->type
))
1916 return TRACE_TYPE_HANDLED
;
1918 return TRACE_TYPE_PARTIAL_LINE
;
1921 static enum print_line_t
print_hex_fmt(struct trace_iterator
*iter
)
1923 struct trace_seq
*s
= &iter
->seq
;
1924 unsigned char newline
= '\n';
1925 struct trace_entry
*entry
;
1926 struct trace_event
*event
;
1930 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1931 SEQ_PUT_HEX_FIELD_RET(s
, entry
->pid
);
1932 SEQ_PUT_HEX_FIELD_RET(s
, iter
->cpu
);
1933 SEQ_PUT_HEX_FIELD_RET(s
, iter
->ts
);
1936 event
= ftrace_find_event(entry
->type
);
1938 enum print_line_t ret
= event
->funcs
->hex(iter
, 0, event
);
1939 if (ret
!= TRACE_TYPE_HANDLED
)
1943 SEQ_PUT_FIELD_RET(s
, newline
);
1945 return TRACE_TYPE_HANDLED
;
1948 static enum print_line_t
print_bin_fmt(struct trace_iterator
*iter
)
1950 struct trace_seq
*s
= &iter
->seq
;
1951 struct trace_entry
*entry
;
1952 struct trace_event
*event
;
1956 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1957 SEQ_PUT_FIELD_RET(s
, entry
->pid
);
1958 SEQ_PUT_FIELD_RET(s
, iter
->cpu
);
1959 SEQ_PUT_FIELD_RET(s
, iter
->ts
);
1962 event
= ftrace_find_event(entry
->type
);
1963 return event
? event
->funcs
->binary(iter
, 0, event
) :
1967 int trace_empty(struct trace_iterator
*iter
)
1971 /* If we are looking at one CPU buffer, only check that one */
1972 if (iter
->cpu_file
!= TRACE_PIPE_ALL_CPU
) {
1973 cpu
= iter
->cpu_file
;
1974 if (iter
->buffer_iter
[cpu
]) {
1975 if (!ring_buffer_iter_empty(iter
->buffer_iter
[cpu
]))
1978 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
1984 for_each_tracing_cpu(cpu
) {
1985 if (iter
->buffer_iter
[cpu
]) {
1986 if (!ring_buffer_iter_empty(iter
->buffer_iter
[cpu
]))
1989 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
1997 /* Called with trace_event_read_lock() held. */
1998 enum print_line_t
print_trace_line(struct trace_iterator
*iter
)
2000 enum print_line_t ret
;
2002 if (iter
->lost_events
)
2003 trace_seq_printf(&iter
->seq
, "CPU:%d [LOST %lu EVENTS]\n",
2004 iter
->cpu
, iter
->lost_events
);
2006 if (iter
->trace
&& iter
->trace
->print_line
) {
2007 ret
= iter
->trace
->print_line(iter
);
2008 if (ret
!= TRACE_TYPE_UNHANDLED
)
2012 if (iter
->ent
->type
== TRACE_BPRINT
&&
2013 trace_flags
& TRACE_ITER_PRINTK
&&
2014 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2015 return trace_print_bprintk_msg_only(iter
);
2017 if (iter
->ent
->type
== TRACE_PRINT
&&
2018 trace_flags
& TRACE_ITER_PRINTK
&&
2019 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2020 return trace_print_printk_msg_only(iter
);
2022 if (trace_flags
& TRACE_ITER_BIN
)
2023 return print_bin_fmt(iter
);
2025 if (trace_flags
& TRACE_ITER_HEX
)
2026 return print_hex_fmt(iter
);
2028 if (trace_flags
& TRACE_ITER_RAW
)
2029 return print_raw_fmt(iter
);
2031 return print_trace_fmt(iter
);
2034 void trace_default_header(struct seq_file
*m
)
2036 struct trace_iterator
*iter
= m
->private;
2038 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
2039 /* print nothing if the buffers are empty */
2040 if (trace_empty(iter
))
2042 print_trace_header(m
, iter
);
2043 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2044 print_lat_help_header(m
);
2046 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2047 print_func_help_header(m
);
2051 static int s_show(struct seq_file
*m
, void *v
)
2053 struct trace_iterator
*iter
= v
;
2056 if (iter
->ent
== NULL
) {
2058 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
2061 if (iter
->trace
&& iter
->trace
->print_header
)
2062 iter
->trace
->print_header(m
);
2064 trace_default_header(m
);
2066 } else if (iter
->leftover
) {
2068 * If we filled the seq_file buffer earlier, we
2069 * want to just show it now.
2071 ret
= trace_print_seq(m
, &iter
->seq
);
2073 /* ret should this time be zero, but you never know */
2074 iter
->leftover
= ret
;
2077 print_trace_line(iter
);
2078 ret
= trace_print_seq(m
, &iter
->seq
);
2080 * If we overflow the seq_file buffer, then it will
2081 * ask us for this data again at start up.
2083 * ret is 0 if seq_file write succeeded.
2086 iter
->leftover
= ret
;
2092 static const struct seq_operations tracer_seq_ops
= {
2099 static struct trace_iterator
*
2100 __tracing_open(struct inode
*inode
, struct file
*file
)
2102 long cpu_file
= (long) inode
->i_private
;
2103 void *fail_ret
= ERR_PTR(-ENOMEM
);
2104 struct trace_iterator
*iter
;
2108 if (tracing_disabled
)
2109 return ERR_PTR(-ENODEV
);
2111 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2113 return ERR_PTR(-ENOMEM
);
2116 * We make a copy of the current tracer to avoid concurrent
2117 * changes on it while we are reading.
2119 mutex_lock(&trace_types_lock
);
2120 iter
->trace
= kzalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
2125 *iter
->trace
= *current_trace
;
2127 if (!zalloc_cpumask_var(&iter
->started
, GFP_KERNEL
))
2130 if (current_trace
&& current_trace
->print_max
)
2133 iter
->tr
= &global_trace
;
2135 mutex_init(&iter
->mutex
);
2136 iter
->cpu_file
= cpu_file
;
2138 /* Notify the tracer early; before we stop tracing. */
2139 if (iter
->trace
&& iter
->trace
->open
)
2140 iter
->trace
->open(iter
);
2142 /* Annotate start of buffers if we had overruns */
2143 if (ring_buffer_overruns(iter
->tr
->buffer
))
2144 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
2146 /* stop the trace while dumping */
2149 if (iter
->cpu_file
== TRACE_PIPE_ALL_CPU
) {
2150 for_each_tracing_cpu(cpu
) {
2151 iter
->buffer_iter
[cpu
] =
2152 ring_buffer_read_prepare(iter
->tr
->buffer
, cpu
);
2154 ring_buffer_read_prepare_sync();
2155 for_each_tracing_cpu(cpu
) {
2156 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2157 tracing_iter_reset(iter
, cpu
);
2160 cpu
= iter
->cpu_file
;
2161 iter
->buffer_iter
[cpu
] =
2162 ring_buffer_read_prepare(iter
->tr
->buffer
, cpu
);
2163 ring_buffer_read_prepare_sync();
2164 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2165 tracing_iter_reset(iter
, cpu
);
2168 ret
= seq_open(file
, &tracer_seq_ops
);
2170 fail_ret
= ERR_PTR(ret
);
2174 m
= file
->private_data
;
2177 mutex_unlock(&trace_types_lock
);
2182 for_each_tracing_cpu(cpu
) {
2183 if (iter
->buffer_iter
[cpu
])
2184 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
2186 free_cpumask_var(iter
->started
);
2189 mutex_unlock(&trace_types_lock
);
2196 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
2198 if (tracing_disabled
)
2201 filp
->private_data
= inode
->i_private
;
2205 static int tracing_release(struct inode
*inode
, struct file
*file
)
2207 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
2208 struct trace_iterator
*iter
;
2211 if (!(file
->f_mode
& FMODE_READ
))
2216 mutex_lock(&trace_types_lock
);
2217 for_each_tracing_cpu(cpu
) {
2218 if (iter
->buffer_iter
[cpu
])
2219 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
2222 if (iter
->trace
&& iter
->trace
->close
)
2223 iter
->trace
->close(iter
);
2225 /* reenable tracing if it was previously enabled */
2227 mutex_unlock(&trace_types_lock
);
2229 seq_release(inode
, file
);
2230 mutex_destroy(&iter
->mutex
);
2231 free_cpumask_var(iter
->started
);
2237 static int tracing_open(struct inode
*inode
, struct file
*file
)
2239 struct trace_iterator
*iter
;
2242 /* If this file was open for write, then erase contents */
2243 if ((file
->f_mode
& FMODE_WRITE
) &&
2244 (file
->f_flags
& O_TRUNC
)) {
2245 long cpu
= (long) inode
->i_private
;
2247 if (cpu
== TRACE_PIPE_ALL_CPU
)
2248 tracing_reset_online_cpus(&global_trace
);
2250 tracing_reset(&global_trace
, cpu
);
2253 if (file
->f_mode
& FMODE_READ
) {
2254 iter
= __tracing_open(inode
, file
);
2256 ret
= PTR_ERR(iter
);
2257 else if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
2258 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
2264 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
2266 struct tracer
*t
= v
;
2276 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
2281 mutex_lock(&trace_types_lock
);
2282 for (t
= trace_types
; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
2288 static void t_stop(struct seq_file
*m
, void *p
)
2290 mutex_unlock(&trace_types_lock
);
2293 static int t_show(struct seq_file
*m
, void *v
)
2295 struct tracer
*t
= v
;
2300 seq_printf(m
, "%s", t
->name
);
2309 static const struct seq_operations show_traces_seq_ops
= {
2316 static int show_traces_open(struct inode
*inode
, struct file
*file
)
2318 if (tracing_disabled
)
2321 return seq_open(file
, &show_traces_seq_ops
);
2325 tracing_write_stub(struct file
*filp
, const char __user
*ubuf
,
2326 size_t count
, loff_t
*ppos
)
2331 static const struct file_operations tracing_fops
= {
2332 .open
= tracing_open
,
2334 .write
= tracing_write_stub
,
2335 .llseek
= seq_lseek
,
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
)
3475 if (tracing_disabled
)
3478 if (cnt
> TRACE_BUF_SIZE
)
3479 cnt
= TRACE_BUF_SIZE
;
3481 buf
= kmalloc(cnt
+ 2, GFP_KERNEL
);
3485 if (copy_from_user(buf
, ubuf
, cnt
)) {
3489 if (buf
[cnt
-1] != '\n') {
3495 cnt
= mark_printk("%s", buf
);
3502 static int tracing_clock_show(struct seq_file
*m
, void *v
)
3506 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++)
3508 "%s%s%s%s", i
? " " : "",
3509 i
== trace_clock_id
? "[" : "", trace_clocks
[i
].name
,
3510 i
== trace_clock_id
? "]" : "");
3516 static ssize_t
tracing_clock_write(struct file
*filp
, const char __user
*ubuf
,
3517 size_t cnt
, loff_t
*fpos
)
3520 const char *clockstr
;
3523 if (cnt
>= sizeof(buf
))
3526 if (copy_from_user(&buf
, ubuf
, cnt
))
3531 clockstr
= strstrip(buf
);
3533 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++) {
3534 if (strcmp(trace_clocks
[i
].name
, clockstr
) == 0)
3537 if (i
== ARRAY_SIZE(trace_clocks
))
3542 mutex_lock(&trace_types_lock
);
3544 ring_buffer_set_clock(global_trace
.buffer
, trace_clocks
[i
].func
);
3546 ring_buffer_set_clock(max_tr
.buffer
, trace_clocks
[i
].func
);
3548 mutex_unlock(&trace_types_lock
);
3555 static int tracing_clock_open(struct inode
*inode
, struct file
*file
)
3557 if (tracing_disabled
)
3559 return single_open(file
, tracing_clock_show
, NULL
);
3562 static const struct file_operations tracing_max_lat_fops
= {
3563 .open
= tracing_open_generic
,
3564 .read
= tracing_max_lat_read
,
3565 .write
= tracing_max_lat_write
,
3566 .llseek
= generic_file_llseek
,
3569 static const struct file_operations tracing_ctrl_fops
= {
3570 .open
= tracing_open_generic
,
3571 .read
= tracing_ctrl_read
,
3572 .write
= tracing_ctrl_write
,
3573 .llseek
= generic_file_llseek
,
3576 static const struct file_operations set_tracer_fops
= {
3577 .open
= tracing_open_generic
,
3578 .read
= tracing_set_trace_read
,
3579 .write
= tracing_set_trace_write
,
3580 .llseek
= generic_file_llseek
,
3583 static const struct file_operations tracing_pipe_fops
= {
3584 .open
= tracing_open_pipe
,
3585 .poll
= tracing_poll_pipe
,
3586 .read
= tracing_read_pipe
,
3587 .splice_read
= tracing_splice_read_pipe
,
3588 .release
= tracing_release_pipe
,
3589 .llseek
= no_llseek
,
3592 static const struct file_operations tracing_entries_fops
= {
3593 .open
= tracing_open_generic
,
3594 .read
= tracing_entries_read
,
3595 .write
= tracing_entries_write
,
3596 .llseek
= generic_file_llseek
,
3599 static const struct file_operations tracing_mark_fops
= {
3600 .open
= tracing_open_generic
,
3601 .write
= tracing_mark_write
,
3602 .llseek
= generic_file_llseek
,
3605 static const struct file_operations trace_clock_fops
= {
3606 .open
= tracing_clock_open
,
3608 .llseek
= seq_lseek
,
3609 .release
= single_release
,
3610 .write
= tracing_clock_write
,
3613 struct ftrace_buffer_info
{
3614 struct trace_array
*tr
;
3620 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
)
3622 int cpu
= (int)(long)inode
->i_private
;
3623 struct ftrace_buffer_info
*info
;
3625 if (tracing_disabled
)
3628 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
3632 info
->tr
= &global_trace
;
3635 /* Force reading ring buffer for first read */
3636 info
->read
= (unsigned int)-1;
3638 filp
->private_data
= info
;
3640 return nonseekable_open(inode
, filp
);
3644 tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
3645 size_t count
, loff_t
*ppos
)
3647 struct ftrace_buffer_info
*info
= filp
->private_data
;
3655 info
->spare
= ring_buffer_alloc_read_page(info
->tr
->buffer
);
3659 /* Do we have previous read data to read? */
3660 if (info
->read
< PAGE_SIZE
)
3665 trace_access_lock(info
->cpu
);
3666 ret
= ring_buffer_read_page(info
->tr
->buffer
,
3670 trace_access_unlock(info
->cpu
);
3675 size
= PAGE_SIZE
- info
->read
;
3679 ret
= copy_to_user(ubuf
, info
->spare
+ info
->read
, size
);
3690 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
)
3692 struct ftrace_buffer_info
*info
= file
->private_data
;
3695 ring_buffer_free_read_page(info
->tr
->buffer
, info
->spare
);
3702 struct ring_buffer
*buffer
;
3707 static void buffer_pipe_buf_release(struct pipe_inode_info
*pipe
,
3708 struct pipe_buffer
*buf
)
3710 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
3715 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
3720 static int buffer_pipe_buf_steal(struct pipe_inode_info
*pipe
,
3721 struct pipe_buffer
*buf
)
3726 static void buffer_pipe_buf_get(struct pipe_inode_info
*pipe
,
3727 struct pipe_buffer
*buf
)
3729 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
3734 /* Pipe buffer operations for a buffer. */
3735 static const struct pipe_buf_operations buffer_pipe_buf_ops
= {
3737 .map
= generic_pipe_buf_map
,
3738 .unmap
= generic_pipe_buf_unmap
,
3739 .confirm
= generic_pipe_buf_confirm
,
3740 .release
= buffer_pipe_buf_release
,
3741 .steal
= buffer_pipe_buf_steal
,
3742 .get
= buffer_pipe_buf_get
,
3746 * Callback from splice_to_pipe(), if we need to release some pages
3747 * at the end of the spd in case we error'ed out in filling the pipe.
3749 static void buffer_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
3751 struct buffer_ref
*ref
=
3752 (struct buffer_ref
*)spd
->partial
[i
].private;
3757 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
3759 spd
->partial
[i
].private = 0;
3763 tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
3764 struct pipe_inode_info
*pipe
, size_t len
,
3767 struct ftrace_buffer_info
*info
= file
->private_data
;
3768 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
3769 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
3770 struct splice_pipe_desc spd
= {
3772 .partial
= partial_def
,
3774 .ops
= &buffer_pipe_buf_ops
,
3775 .spd_release
= buffer_spd_release
,
3777 struct buffer_ref
*ref
;
3778 int entries
, size
, i
;
3781 if (splice_grow_spd(pipe
, &spd
))
3784 if (*ppos
& (PAGE_SIZE
- 1)) {
3785 WARN_ONCE(1, "Ftrace: previous read must page-align\n");
3790 if (len
& (PAGE_SIZE
- 1)) {
3791 WARN_ONCE(1, "Ftrace: splice_read should page-align\n");
3792 if (len
< PAGE_SIZE
) {
3799 trace_access_lock(info
->cpu
);
3800 entries
= ring_buffer_entries_cpu(info
->tr
->buffer
, info
->cpu
);
3802 for (i
= 0; i
< pipe
->buffers
&& len
&& entries
; i
++, len
-= PAGE_SIZE
) {
3806 ref
= kzalloc(sizeof(*ref
), GFP_KERNEL
);
3811 ref
->buffer
= info
->tr
->buffer
;
3812 ref
->page
= ring_buffer_alloc_read_page(ref
->buffer
);
3818 r
= ring_buffer_read_page(ref
->buffer
, &ref
->page
,
3821 ring_buffer_free_read_page(ref
->buffer
,
3828 * zero out any left over data, this is going to
3831 size
= ring_buffer_page_len(ref
->page
);
3832 if (size
< PAGE_SIZE
)
3833 memset(ref
->page
+ size
, 0, PAGE_SIZE
- size
);
3835 page
= virt_to_page(ref
->page
);
3837 spd
.pages
[i
] = page
;
3838 spd
.partial
[i
].len
= PAGE_SIZE
;
3839 spd
.partial
[i
].offset
= 0;
3840 spd
.partial
[i
].private = (unsigned long)ref
;
3844 entries
= ring_buffer_entries_cpu(info
->tr
->buffer
, info
->cpu
);
3847 trace_access_unlock(info
->cpu
);
3850 /* did we read anything? */
3851 if (!spd
.nr_pages
) {
3852 if (flags
& SPLICE_F_NONBLOCK
)
3860 ret
= splice_to_pipe(pipe
, &spd
);
3861 splice_shrink_spd(pipe
, &spd
);
3866 static const struct file_operations tracing_buffers_fops
= {
3867 .open
= tracing_buffers_open
,
3868 .read
= tracing_buffers_read
,
3869 .release
= tracing_buffers_release
,
3870 .splice_read
= tracing_buffers_splice_read
,
3871 .llseek
= no_llseek
,
3875 tracing_stats_read(struct file
*filp
, char __user
*ubuf
,
3876 size_t count
, loff_t
*ppos
)
3878 unsigned long cpu
= (unsigned long)filp
->private_data
;
3879 struct trace_array
*tr
= &global_trace
;
3880 struct trace_seq
*s
;
3883 s
= kmalloc(sizeof(*s
), GFP_KERNEL
);
3889 cnt
= ring_buffer_entries_cpu(tr
->buffer
, cpu
);
3890 trace_seq_printf(s
, "entries: %ld\n", cnt
);
3892 cnt
= ring_buffer_overrun_cpu(tr
->buffer
, cpu
);
3893 trace_seq_printf(s
, "overrun: %ld\n", cnt
);
3895 cnt
= ring_buffer_commit_overrun_cpu(tr
->buffer
, cpu
);
3896 trace_seq_printf(s
, "commit overrun: %ld\n", cnt
);
3898 count
= simple_read_from_buffer(ubuf
, count
, ppos
, s
->buffer
, s
->len
);
3905 static const struct file_operations tracing_stats_fops
= {
3906 .open
= tracing_open_generic
,
3907 .read
= tracing_stats_read
,
3908 .llseek
= generic_file_llseek
,
3911 #ifdef CONFIG_DYNAMIC_FTRACE
3913 int __weak
ftrace_arch_read_dyn_info(char *buf
, int size
)
3919 tracing_read_dyn_info(struct file
*filp
, char __user
*ubuf
,
3920 size_t cnt
, loff_t
*ppos
)
3922 static char ftrace_dyn_info_buffer
[1024];
3923 static DEFINE_MUTEX(dyn_info_mutex
);
3924 unsigned long *p
= filp
->private_data
;
3925 char *buf
= ftrace_dyn_info_buffer
;
3926 int size
= ARRAY_SIZE(ftrace_dyn_info_buffer
);
3929 mutex_lock(&dyn_info_mutex
);
3930 r
= sprintf(buf
, "%ld ", *p
);
3932 r
+= ftrace_arch_read_dyn_info(buf
+r
, (size
-1)-r
);
3935 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3937 mutex_unlock(&dyn_info_mutex
);
3942 static const struct file_operations tracing_dyn_info_fops
= {
3943 .open
= tracing_open_generic
,
3944 .read
= tracing_read_dyn_info
,
3945 .llseek
= generic_file_llseek
,
3949 static struct dentry
*d_tracer
;
3951 struct dentry
*tracing_init_dentry(void)
3958 if (!debugfs_initialized())
3961 d_tracer
= debugfs_create_dir("tracing", NULL
);
3963 if (!d_tracer
&& !once
) {
3965 pr_warning("Could not create debugfs directory 'tracing'\n");
3972 static struct dentry
*d_percpu
;
3974 struct dentry
*tracing_dentry_percpu(void)
3977 struct dentry
*d_tracer
;
3982 d_tracer
= tracing_init_dentry();
3987 d_percpu
= debugfs_create_dir("per_cpu", d_tracer
);
3989 if (!d_percpu
&& !once
) {
3991 pr_warning("Could not create debugfs directory 'per_cpu'\n");
3998 static void tracing_init_debugfs_percpu(long cpu
)
4000 struct dentry
*d_percpu
= tracing_dentry_percpu();
4001 struct dentry
*d_cpu
;
4002 /* strlen(cpu) + MAX(log10(cpu)) + '\0' */
4005 if (cpu
> 999 || cpu
< 0)
4008 sprintf(cpu_dir
, "cpu%ld", cpu
);
4009 d_cpu
= debugfs_create_dir(cpu_dir
, d_percpu
);
4011 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir
);
4015 /* per cpu trace_pipe */
4016 trace_create_file("trace_pipe", 0444, d_cpu
,
4017 (void *) cpu
, &tracing_pipe_fops
);
4020 trace_create_file("trace", 0644, d_cpu
,
4021 (void *) cpu
, &tracing_fops
);
4023 trace_create_file("trace_pipe_raw", 0444, d_cpu
,
4024 (void *) cpu
, &tracing_buffers_fops
);
4026 trace_create_file("stats", 0444, d_cpu
,
4027 (void *) cpu
, &tracing_stats_fops
);
4030 #ifdef CONFIG_FTRACE_SELFTEST
4031 /* Let selftest have access to static functions in this file */
4032 #include "trace_selftest.c"
4035 struct trace_option_dentry
{
4036 struct tracer_opt
*opt
;
4037 struct tracer_flags
*flags
;
4038 struct dentry
*entry
;
4042 trace_options_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
4045 struct trace_option_dentry
*topt
= filp
->private_data
;
4048 if (topt
->flags
->val
& topt
->opt
->bit
)
4053 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
4057 trace_options_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
4060 struct trace_option_dentry
*topt
= filp
->private_data
;
4065 if (cnt
>= sizeof(buf
))
4068 if (copy_from_user(&buf
, ubuf
, cnt
))
4073 ret
= strict_strtoul(buf
, 10, &val
);
4077 if (val
!= 0 && val
!= 1)
4080 if (!!(topt
->flags
->val
& topt
->opt
->bit
) != val
) {
4081 mutex_lock(&trace_types_lock
);
4082 ret
= __set_tracer_option(current_trace
, topt
->flags
,
4084 mutex_unlock(&trace_types_lock
);
4095 static const struct file_operations trace_options_fops
= {
4096 .open
= tracing_open_generic
,
4097 .read
= trace_options_read
,
4098 .write
= trace_options_write
,
4099 .llseek
= generic_file_llseek
,
4103 trace_options_core_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
4106 long index
= (long)filp
->private_data
;
4109 if (trace_flags
& (1 << index
))
4114 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
4118 trace_options_core_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
4121 long index
= (long)filp
->private_data
;
4126 if (cnt
>= sizeof(buf
))
4129 if (copy_from_user(&buf
, ubuf
, cnt
))
4134 ret
= strict_strtoul(buf
, 10, &val
);
4138 if (val
!= 0 && val
!= 1)
4140 set_tracer_flags(1 << index
, val
);
4147 static const struct file_operations trace_options_core_fops
= {
4148 .open
= tracing_open_generic
,
4149 .read
= trace_options_core_read
,
4150 .write
= trace_options_core_write
,
4151 .llseek
= generic_file_llseek
,
4154 struct dentry
*trace_create_file(const char *name
,
4156 struct dentry
*parent
,
4158 const struct file_operations
*fops
)
4162 ret
= debugfs_create_file(name
, mode
, parent
, data
, fops
);
4164 pr_warning("Could not create debugfs '%s' entry\n", name
);
4170 static struct dentry
*trace_options_init_dentry(void)
4172 struct dentry
*d_tracer
;
4173 static struct dentry
*t_options
;
4178 d_tracer
= tracing_init_dentry();
4182 t_options
= debugfs_create_dir("options", d_tracer
);
4184 pr_warning("Could not create debugfs directory 'options'\n");
4192 create_trace_option_file(struct trace_option_dentry
*topt
,
4193 struct tracer_flags
*flags
,
4194 struct tracer_opt
*opt
)
4196 struct dentry
*t_options
;
4198 t_options
= trace_options_init_dentry();
4202 topt
->flags
= flags
;
4205 topt
->entry
= trace_create_file(opt
->name
, 0644, t_options
, topt
,
4206 &trace_options_fops
);
4210 static struct trace_option_dentry
*
4211 create_trace_option_files(struct tracer
*tracer
)
4213 struct trace_option_dentry
*topts
;
4214 struct tracer_flags
*flags
;
4215 struct tracer_opt
*opts
;
4221 flags
= tracer
->flags
;
4223 if (!flags
|| !flags
->opts
)
4228 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
4231 topts
= kcalloc(cnt
+ 1, sizeof(*topts
), GFP_KERNEL
);
4235 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
4236 create_trace_option_file(&topts
[cnt
], flags
,
4243 destroy_trace_option_files(struct trace_option_dentry
*topts
)
4250 for (cnt
= 0; topts
[cnt
].opt
; cnt
++) {
4251 if (topts
[cnt
].entry
)
4252 debugfs_remove(topts
[cnt
].entry
);
4258 static struct dentry
*
4259 create_trace_option_core_file(const char *option
, long index
)
4261 struct dentry
*t_options
;
4263 t_options
= trace_options_init_dentry();
4267 return trace_create_file(option
, 0644, t_options
, (void *)index
,
4268 &trace_options_core_fops
);
4271 static __init
void create_trace_options_dir(void)
4273 struct dentry
*t_options
;
4276 t_options
= trace_options_init_dentry();
4280 for (i
= 0; trace_options
[i
]; i
++)
4281 create_trace_option_core_file(trace_options
[i
], i
);
4284 static __init
int tracer_init_debugfs(void)
4286 struct dentry
*d_tracer
;
4289 trace_access_lock_init();
4291 d_tracer
= tracing_init_dentry();
4293 trace_create_file("tracing_enabled", 0644, d_tracer
,
4294 &global_trace
, &tracing_ctrl_fops
);
4296 trace_create_file("trace_options", 0644, d_tracer
,
4297 NULL
, &tracing_iter_fops
);
4299 trace_create_file("tracing_cpumask", 0644, d_tracer
,
4300 NULL
, &tracing_cpumask_fops
);
4302 trace_create_file("trace", 0644, d_tracer
,
4303 (void *) TRACE_PIPE_ALL_CPU
, &tracing_fops
);
4305 trace_create_file("available_tracers", 0444, d_tracer
,
4306 &global_trace
, &show_traces_fops
);
4308 trace_create_file("current_tracer", 0644, d_tracer
,
4309 &global_trace
, &set_tracer_fops
);
4311 #ifdef CONFIG_TRACER_MAX_TRACE
4312 trace_create_file("tracing_max_latency", 0644, d_tracer
,
4313 &tracing_max_latency
, &tracing_max_lat_fops
);
4316 trace_create_file("tracing_thresh", 0644, d_tracer
,
4317 &tracing_thresh
, &tracing_max_lat_fops
);
4319 trace_create_file("README", 0444, d_tracer
,
4320 NULL
, &tracing_readme_fops
);
4322 trace_create_file("trace_pipe", 0444, d_tracer
,
4323 (void *) TRACE_PIPE_ALL_CPU
, &tracing_pipe_fops
);
4325 trace_create_file("buffer_size_kb", 0644, d_tracer
,
4326 &global_trace
, &tracing_entries_fops
);
4328 trace_create_file("trace_marker", 0220, d_tracer
,
4329 NULL
, &tracing_mark_fops
);
4331 trace_create_file("saved_cmdlines", 0444, d_tracer
,
4332 NULL
, &tracing_saved_cmdlines_fops
);
4334 trace_create_file("trace_clock", 0644, d_tracer
, NULL
,
4337 #ifdef CONFIG_DYNAMIC_FTRACE
4338 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
4339 &ftrace_update_tot_cnt
, &tracing_dyn_info_fops
);
4342 create_trace_options_dir();
4344 for_each_tracing_cpu(cpu
)
4345 tracing_init_debugfs_percpu(cpu
);
4350 static int trace_panic_handler(struct notifier_block
*this,
4351 unsigned long event
, void *unused
)
4353 if (ftrace_dump_on_oops
)
4354 ftrace_dump(ftrace_dump_on_oops
);
4358 static struct notifier_block trace_panic_notifier
= {
4359 .notifier_call
= trace_panic_handler
,
4361 .priority
= 150 /* priority: INT_MAX >= x >= 0 */
4364 static int trace_die_handler(struct notifier_block
*self
,
4370 if (ftrace_dump_on_oops
)
4371 ftrace_dump(ftrace_dump_on_oops
);
4379 static struct notifier_block trace_die_notifier
= {
4380 .notifier_call
= trace_die_handler
,
4385 * printk is set to max of 1024, we really don't need it that big.
4386 * Nothing should be printing 1000 characters anyway.
4388 #define TRACE_MAX_PRINT 1000
4391 * Define here KERN_TRACE so that we have one place to modify
4392 * it if we decide to change what log level the ftrace dump
4395 #define KERN_TRACE KERN_EMERG
4398 trace_printk_seq(struct trace_seq
*s
)
4400 /* Probably should print a warning here. */
4404 /* should be zero ended, but we are paranoid. */
4405 s
->buffer
[s
->len
] = 0;
4407 printk(KERN_TRACE
"%s", s
->buffer
);
4412 void trace_init_global_iter(struct trace_iterator
*iter
)
4414 iter
->tr
= &global_trace
;
4415 iter
->trace
= current_trace
;
4416 iter
->cpu_file
= TRACE_PIPE_ALL_CPU
;
4420 __ftrace_dump(bool disable_tracing
, enum ftrace_dump_mode oops_dump_mode
)
4422 static arch_spinlock_t ftrace_dump_lock
=
4423 (arch_spinlock_t
)__ARCH_SPIN_LOCK_UNLOCKED
;
4424 /* use static because iter can be a bit big for the stack */
4425 static struct trace_iterator iter
;
4426 unsigned int old_userobj
;
4427 static int dump_ran
;
4428 unsigned long flags
;
4432 local_irq_save(flags
);
4433 arch_spin_lock(&ftrace_dump_lock
);
4441 if (disable_tracing
)
4444 trace_init_global_iter(&iter
);
4446 for_each_tracing_cpu(cpu
) {
4447 atomic_inc(&iter
.tr
->data
[cpu
]->disabled
);
4450 old_userobj
= trace_flags
& TRACE_ITER_SYM_USEROBJ
;
4452 /* don't look at user memory in panic mode */
4453 trace_flags
&= ~TRACE_ITER_SYM_USEROBJ
;
4455 /* Simulate the iterator */
4456 iter
.tr
= &global_trace
;
4457 iter
.trace
= current_trace
;
4459 switch (oops_dump_mode
) {
4461 iter
.cpu_file
= TRACE_PIPE_ALL_CPU
;
4464 iter
.cpu_file
= raw_smp_processor_id();
4469 printk(KERN_TRACE
"Bad dumping mode, switching to all CPUs dump\n");
4470 iter
.cpu_file
= TRACE_PIPE_ALL_CPU
;
4473 printk(KERN_TRACE
"Dumping ftrace buffer:\n");
4476 * We need to stop all tracing on all CPUS to read the
4477 * the next buffer. This is a bit expensive, but is
4478 * not done often. We fill all what we can read,
4479 * and then release the locks again.
4482 while (!trace_empty(&iter
)) {
4485 printk(KERN_TRACE
"---------------------------------\n");
4489 /* reset all but tr, trace, and overruns */
4490 memset(&iter
.seq
, 0,
4491 sizeof(struct trace_iterator
) -
4492 offsetof(struct trace_iterator
, seq
));
4493 iter
.iter_flags
|= TRACE_FILE_LAT_FMT
;
4496 if (trace_find_next_entry_inc(&iter
) != NULL
) {
4499 ret
= print_trace_line(&iter
);
4500 if (ret
!= TRACE_TYPE_NO_CONSUME
)
4501 trace_consume(&iter
);
4504 trace_printk_seq(&iter
.seq
);
4508 printk(KERN_TRACE
" (ftrace buffer empty)\n");
4510 printk(KERN_TRACE
"---------------------------------\n");
4513 /* Re-enable tracing if requested */
4514 if (!disable_tracing
) {
4515 trace_flags
|= old_userobj
;
4517 for_each_tracing_cpu(cpu
) {
4518 atomic_dec(&iter
.tr
->data
[cpu
]->disabled
);
4524 arch_spin_unlock(&ftrace_dump_lock
);
4525 local_irq_restore(flags
);
4528 /* By default: disable tracing after the dump */
4529 void ftrace_dump(enum ftrace_dump_mode oops_dump_mode
)
4531 __ftrace_dump(true, oops_dump_mode
);
4534 __init
static int tracer_alloc_buffers(void)
4540 if (!alloc_cpumask_var(&tracing_buffer_mask
, GFP_KERNEL
))
4543 if (!alloc_cpumask_var(&tracing_cpumask
, GFP_KERNEL
))
4544 goto out_free_buffer_mask
;
4546 /* To save memory, keep the ring buffer size to its minimum */
4547 if (ring_buffer_expanded
)
4548 ring_buf_size
= trace_buf_size
;
4552 cpumask_copy(tracing_buffer_mask
, cpu_possible_mask
);
4553 cpumask_copy(tracing_cpumask
, cpu_all_mask
);
4555 /* TODO: make the number of buffers hot pluggable with CPUS */
4556 global_trace
.buffer
= ring_buffer_alloc(ring_buf_size
,
4557 TRACE_BUFFER_FLAGS
);
4558 if (!global_trace
.buffer
) {
4559 printk(KERN_ERR
"tracer: failed to allocate ring buffer!\n");
4561 goto out_free_cpumask
;
4563 global_trace
.entries
= ring_buffer_size(global_trace
.buffer
);
4566 #ifdef CONFIG_TRACER_MAX_TRACE
4567 max_tr
.buffer
= ring_buffer_alloc(1, TRACE_BUFFER_FLAGS
);
4568 if (!max_tr
.buffer
) {
4569 printk(KERN_ERR
"tracer: failed to allocate max ring buffer!\n");
4571 ring_buffer_free(global_trace
.buffer
);
4572 goto out_free_cpumask
;
4577 /* Allocate the first page for all buffers */
4578 for_each_tracing_cpu(i
) {
4579 global_trace
.data
[i
] = &per_cpu(global_trace_cpu
, i
);
4580 max_tr
.data
[i
] = &per_cpu(max_tr_data
, i
);
4583 trace_init_cmdlines();
4585 register_tracer(&nop_trace
);
4586 current_trace
= &nop_trace
;
4587 /* All seems OK, enable tracing */
4588 tracing_disabled
= 0;
4590 atomic_notifier_chain_register(&panic_notifier_list
,
4591 &trace_panic_notifier
);
4593 register_die_notifier(&trace_die_notifier
);
4598 free_cpumask_var(tracing_cpumask
);
4599 out_free_buffer_mask
:
4600 free_cpumask_var(tracing_buffer_mask
);
4605 __init
static int clear_boot_tracer(void)
4608 * The default tracer at boot buffer is an init section.
4609 * This function is called in lateinit. If we did not
4610 * find the boot tracer, then clear it out, to prevent
4611 * later registration from accessing the buffer that is
4612 * about to be freed.
4614 if (!default_bootup_tracer
)
4617 printk(KERN_INFO
"ftrace bootup tracer '%s' not registered.\n",
4618 default_bootup_tracer
);
4619 default_bootup_tracer
= NULL
;
4624 early_initcall(tracer_alloc_buffers
);
4625 fs_initcall(tracer_init_debugfs
);
4626 late_initcall(clear_boot_tracer
);