2 * ring buffer based function tracer
4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
7 * Originally taken from the RT patch by:
8 * Arnaldo Carvalho de Melo <acme@redhat.com>
10 * Based on code from the latency_tracer, that is:
11 * Copyright (C) 2004-2006 Ingo Molnar
12 * Copyright (C) 2004 William Lee Irwin III
14 #include <linux/ring_buffer.h>
15 #include <generated/utsrelease.h>
16 #include <linux/stacktrace.h>
17 #include <linux/writeback.h>
18 #include <linux/kallsyms.h>
19 #include <linux/seq_file.h>
20 #include <linux/notifier.h>
21 #include <linux/irqflags.h>
22 #include <linux/debugfs.h>
23 #include <linux/pagemap.h>
24 #include <linux/hardirq.h>
25 #include <linux/linkage.h>
26 #include <linux/uaccess.h>
27 #include <linux/kprobes.h>
28 #include <linux/ftrace.h>
29 #include <linux/module.h>
30 #include <linux/percpu.h>
31 #include <linux/splice.h>
32 #include <linux/kdebug.h>
33 #include <linux/string.h>
34 #include <linux/rwsem.h>
35 #include <linux/slab.h>
36 #include <linux/ctype.h>
37 #include <linux/init.h>
38 #include <linux/poll.h>
39 #include <linux/nmi.h>
43 #include "trace_output.h"
46 * On boot up, the ring buffer is set to the minimum size, so that
47 * we do not waste memory on systems that are not using tracing.
49 int ring_buffer_expanded
;
52 * We need to change this state when a selftest is running.
53 * A selftest will lurk into the ring-buffer to count the
54 * entries inserted during the selftest although some concurrent
55 * insertions into the ring-buffer such as trace_printk could occurred
56 * at the same time, giving false positive or negative results.
58 static bool __read_mostly tracing_selftest_running
;
61 * If a tracer is running, we do not want to run SELFTEST.
63 bool __read_mostly tracing_selftest_disabled
;
65 /* For tracers that don't implement custom flags */
66 static struct tracer_opt dummy_tracer_opt
[] = {
70 static struct tracer_flags dummy_tracer_flags
= {
72 .opts
= dummy_tracer_opt
75 static int dummy_set_flag(u32 old_flags
, u32 bit
, int set
)
81 * Kill all tracing for good (never come back).
82 * It is initialized to 1 but will turn to zero if the initialization
83 * of the tracer is successful. But that is the only place that sets
86 static int tracing_disabled
= 1;
88 DEFINE_PER_CPU(int, ftrace_cpu_disabled
);
90 static inline void ftrace_disable_cpu(void)
93 __this_cpu_inc(ftrace_cpu_disabled
);
96 static inline void ftrace_enable_cpu(void)
98 __this_cpu_dec(ftrace_cpu_disabled
);
102 cpumask_var_t __read_mostly tracing_buffer_mask
;
105 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
107 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
108 * is set, then ftrace_dump is called. This will output the contents
109 * of the ftrace buffers to the console. This is very useful for
110 * capturing traces that lead to crashes and outputing it to a
113 * It is default off, but you can enable it with either specifying
114 * "ftrace_dump_on_oops" in the kernel command line, or setting
115 * /proc/sys/kernel/ftrace_dump_on_oops
116 * Set 1 if you want to dump buffers of all CPUs
117 * Set 2 if you want to dump the buffer of the CPU that triggered oops
120 enum ftrace_dump_mode ftrace_dump_on_oops
;
122 static int tracing_set_tracer(const char *buf
);
124 #define MAX_TRACER_SIZE 100
125 static char bootup_tracer_buf
[MAX_TRACER_SIZE
] __initdata
;
126 static char *default_bootup_tracer
;
128 static int __init
set_cmdline_ftrace(char *str
)
130 strncpy(bootup_tracer_buf
, str
, MAX_TRACER_SIZE
);
131 default_bootup_tracer
= bootup_tracer_buf
;
132 /* We are using ftrace early, expand it */
133 ring_buffer_expanded
= 1;
136 __setup("ftrace=", set_cmdline_ftrace
);
138 static int __init
set_ftrace_dump_on_oops(char *str
)
140 if (*str
++ != '=' || !*str
) {
141 ftrace_dump_on_oops
= DUMP_ALL
;
145 if (!strcmp("orig_cpu", str
)) {
146 ftrace_dump_on_oops
= DUMP_ORIG
;
152 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops
);
154 unsigned long long ns2usecs(cycle_t nsec
)
162 * The global_trace is the descriptor that holds the tracing
163 * buffers for the live tracing. For each CPU, it contains
164 * a link list of pages that will store trace entries. The
165 * page descriptor of the pages in the memory is used to hold
166 * the link list by linking the lru item in the page descriptor
167 * to each of the pages in the buffer per CPU.
169 * For each active CPU there is a data field that holds the
170 * pages for the buffer for that CPU. Each CPU has the same number
171 * of pages allocated for its buffer.
173 static struct trace_array global_trace
;
175 static DEFINE_PER_CPU(struct trace_array_cpu
, global_trace_cpu
);
177 int filter_current_check_discard(struct ring_buffer
*buffer
,
178 struct ftrace_event_call
*call
, void *rec
,
179 struct ring_buffer_event
*event
)
181 return filter_check_discard(call
, rec
, buffer
, event
);
183 EXPORT_SYMBOL_GPL(filter_current_check_discard
);
185 cycle_t
ftrace_now(int cpu
)
189 /* Early boot up does not have a buffer yet */
190 if (!global_trace
.buffer
)
191 return trace_clock_local();
193 ts
= ring_buffer_time_stamp(global_trace
.buffer
, cpu
);
194 ring_buffer_normalize_time_stamp(global_trace
.buffer
, cpu
, &ts
);
200 * The max_tr is used to snapshot the global_trace when a maximum
201 * latency is reached. Some tracers will use this to store a maximum
202 * trace while it continues examining live traces.
204 * The buffers for the max_tr are set up the same as the global_trace.
205 * When a snapshot is taken, the link list of the max_tr is swapped
206 * with the link list of the global_trace and the buffers are reset for
207 * the global_trace so the tracing can continue.
209 static struct trace_array max_tr
;
211 static DEFINE_PER_CPU(struct trace_array_cpu
, max_tr_data
);
213 /* tracer_enabled is used to toggle activation of a tracer */
214 static int tracer_enabled
= 1;
217 * tracing_is_enabled - return tracer_enabled status
219 * This function is used by other tracers to know the status
220 * of the tracer_enabled flag. Tracers may use this function
221 * to know if it should enable their features when starting
222 * up. See irqsoff tracer for an example (start_irqsoff_tracer).
224 int tracing_is_enabled(void)
226 return tracer_enabled
;
230 * trace_buf_size is the size in bytes that is allocated
231 * for a buffer. Note, the number of bytes is always rounded
234 * This number is purposely set to a low number of 16384.
235 * If the dump on oops happens, it will be much appreciated
236 * to not have to wait for all that output. Anyway this can be
237 * boot time and run time configurable.
239 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
241 static unsigned long trace_buf_size
= TRACE_BUF_SIZE_DEFAULT
;
243 /* trace_types holds a link list of available tracers. */
244 static struct tracer
*trace_types __read_mostly
;
246 /* current_trace points to the tracer that is currently active */
247 static struct tracer
*current_trace __read_mostly
;
250 * trace_types_lock is used to protect the trace_types list.
252 static DEFINE_MUTEX(trace_types_lock
);
255 * serialize the access of the ring buffer
257 * ring buffer serializes readers, but it is low level protection.
258 * The validity of the events (which returns by ring_buffer_peek() ..etc)
259 * are not protected by ring buffer.
261 * The content of events may become garbage if we allow other process consumes
262 * these events concurrently:
263 * A) the page of the consumed events may become a normal page
264 * (not reader page) in ring buffer, and this page will be rewrited
265 * by events producer.
266 * B) The page of the consumed events may become a page for splice_read,
267 * and this page will be returned to system.
269 * These primitives allow multi process access to different cpu ring buffer
272 * These primitives don't distinguish read-only and read-consume access.
273 * Multi read-only access are also serialized.
277 static DECLARE_RWSEM(all_cpu_access_lock
);
278 static DEFINE_PER_CPU(struct mutex
, cpu_access_lock
);
280 static inline void trace_access_lock(int cpu
)
282 if (cpu
== TRACE_PIPE_ALL_CPU
) {
283 /* gain it for accessing the whole ring buffer. */
284 down_write(&all_cpu_access_lock
);
286 /* gain it for accessing a cpu ring buffer. */
288 /* Firstly block other trace_access_lock(TRACE_PIPE_ALL_CPU). */
289 down_read(&all_cpu_access_lock
);
291 /* Secondly block other access to this @cpu ring buffer. */
292 mutex_lock(&per_cpu(cpu_access_lock
, cpu
));
296 static inline void trace_access_unlock(int cpu
)
298 if (cpu
== TRACE_PIPE_ALL_CPU
) {
299 up_write(&all_cpu_access_lock
);
301 mutex_unlock(&per_cpu(cpu_access_lock
, cpu
));
302 up_read(&all_cpu_access_lock
);
306 static inline void trace_access_lock_init(void)
310 for_each_possible_cpu(cpu
)
311 mutex_init(&per_cpu(cpu_access_lock
, cpu
));
316 static DEFINE_MUTEX(access_lock
);
318 static inline void trace_access_lock(int cpu
)
321 mutex_lock(&access_lock
);
324 static inline void trace_access_unlock(int cpu
)
327 mutex_unlock(&access_lock
);
330 static inline void trace_access_lock_init(void)
336 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
337 static DECLARE_WAIT_QUEUE_HEAD(trace_wait
);
339 /* trace_flags holds trace_options default values */
340 unsigned long trace_flags
= TRACE_ITER_PRINT_PARENT
| TRACE_ITER_PRINTK
|
341 TRACE_ITER_ANNOTATE
| TRACE_ITER_CONTEXT_INFO
| TRACE_ITER_SLEEP_TIME
|
342 TRACE_ITER_GRAPH_TIME
| TRACE_ITER_RECORD_CMD
| TRACE_ITER_OVERWRITE
|
345 static int trace_stop_count
;
346 static DEFINE_RAW_SPINLOCK(tracing_start_lock
);
348 static void wakeup_work_handler(struct work_struct
*work
)
350 wake_up(&trace_wait
);
353 static DECLARE_DELAYED_WORK(wakeup_work
, wakeup_work_handler
);
356 * tracing_on - enable tracing buffers
358 * This function enables tracing buffers that may have been
359 * disabled with tracing_off.
361 void tracing_on(void)
363 if (global_trace
.buffer
)
364 ring_buffer_record_on(global_trace
.buffer
);
366 * This flag is only looked at when buffers haven't been
367 * allocated yet. We don't really care about the race
368 * between setting this flag and actually turning
371 global_trace
.buffer_disabled
= 0;
373 EXPORT_SYMBOL_GPL(tracing_on
);
376 * tracing_off - turn off tracing buffers
378 * This function stops the tracing buffers from recording data.
379 * It does not disable any overhead the tracers themselves may
380 * be causing. This function simply causes all recording to
381 * the ring buffers to fail.
383 void tracing_off(void)
385 if (global_trace
.buffer
)
386 ring_buffer_record_on(global_trace
.buffer
);
388 * This flag is only looked at when buffers haven't been
389 * allocated yet. We don't really care about the race
390 * between setting this flag and actually turning
393 global_trace
.buffer_disabled
= 1;
395 EXPORT_SYMBOL_GPL(tracing_off
);
398 * tracing_is_on - show state of ring buffers enabled
400 int tracing_is_on(void)
402 if (global_trace
.buffer
)
403 return ring_buffer_record_is_on(global_trace
.buffer
);
404 return !global_trace
.buffer_disabled
;
406 EXPORT_SYMBOL_GPL(tracing_is_on
);
409 * trace_wake_up - wake up tasks waiting for trace input
411 * Schedules a delayed work to wake up any task that is blocked on the
412 * trace_wait queue. These is used with trace_poll for tasks polling the
415 void trace_wake_up(void)
417 const unsigned long delay
= msecs_to_jiffies(2);
419 if (trace_flags
& TRACE_ITER_BLOCK
)
421 schedule_delayed_work(&wakeup_work
, delay
);
424 static int __init
set_buf_size(char *str
)
426 unsigned long buf_size
;
430 buf_size
= memparse(str
, &str
);
431 /* nr_entries can not be zero */
434 trace_buf_size
= buf_size
;
437 __setup("trace_buf_size=", set_buf_size
);
439 static int __init
set_tracing_thresh(char *str
)
441 unsigned long threshhold
;
446 ret
= strict_strtoul(str
, 0, &threshhold
);
449 tracing_thresh
= threshhold
* 1000;
452 __setup("tracing_thresh=", set_tracing_thresh
);
454 unsigned long nsecs_to_usecs(unsigned long nsecs
)
459 /* These must match the bit postions in trace_iterator_flags */
460 static const char *trace_options
[] = {
492 { trace_clock_local
, "local" },
493 { trace_clock_global
, "global" },
494 { trace_clock_counter
, "counter" },
500 * trace_parser_get_init - gets the buffer for trace parser
502 int trace_parser_get_init(struct trace_parser
*parser
, int size
)
504 memset(parser
, 0, sizeof(*parser
));
506 parser
->buffer
= kmalloc(size
, GFP_KERNEL
);
515 * trace_parser_put - frees the buffer for trace parser
517 void trace_parser_put(struct trace_parser
*parser
)
519 kfree(parser
->buffer
);
523 * trace_get_user - reads the user input string separated by space
524 * (matched by isspace(ch))
526 * For each string found the 'struct trace_parser' is updated,
527 * and the function returns.
529 * Returns number of bytes read.
531 * See kernel/trace/trace.h for 'struct trace_parser' details.
533 int trace_get_user(struct trace_parser
*parser
, const char __user
*ubuf
,
534 size_t cnt
, loff_t
*ppos
)
541 trace_parser_clear(parser
);
543 ret
= get_user(ch
, ubuf
++);
551 * The parser is not finished with the last write,
552 * continue reading the user input without skipping spaces.
555 /* skip white space */
556 while (cnt
&& isspace(ch
)) {
557 ret
= get_user(ch
, ubuf
++);
564 /* only spaces were written */
574 /* read the non-space input */
575 while (cnt
&& !isspace(ch
)) {
576 if (parser
->idx
< parser
->size
- 1)
577 parser
->buffer
[parser
->idx
++] = ch
;
582 ret
= get_user(ch
, ubuf
++);
589 /* We either got finished input or we have to wait for another call. */
591 parser
->buffer
[parser
->idx
] = 0;
592 parser
->cont
= false;
595 parser
->buffer
[parser
->idx
++] = ch
;
605 ssize_t
trace_seq_to_user(struct trace_seq
*s
, char __user
*ubuf
, size_t cnt
)
613 if (s
->len
<= s
->readpos
)
616 len
= s
->len
- s
->readpos
;
619 ret
= copy_to_user(ubuf
, s
->buffer
+ s
->readpos
, cnt
);
629 static ssize_t
trace_seq_to_buffer(struct trace_seq
*s
, void *buf
, size_t cnt
)
634 if (s
->len
<= s
->readpos
)
637 len
= s
->len
- s
->readpos
;
640 ret
= memcpy(buf
, s
->buffer
+ s
->readpos
, cnt
);
649 * ftrace_max_lock is used to protect the swapping of buffers
650 * when taking a max snapshot. The buffers themselves are
651 * protected by per_cpu spinlocks. But the action of the swap
652 * needs its own lock.
654 * This is defined as a arch_spinlock_t in order to help
655 * with performance when lockdep debugging is enabled.
657 * It is also used in other places outside the update_max_tr
658 * so it needs to be defined outside of the
659 * CONFIG_TRACER_MAX_TRACE.
661 static arch_spinlock_t ftrace_max_lock
=
662 (arch_spinlock_t
)__ARCH_SPIN_LOCK_UNLOCKED
;
664 unsigned long __read_mostly tracing_thresh
;
666 #ifdef CONFIG_TRACER_MAX_TRACE
667 unsigned long __read_mostly tracing_max_latency
;
670 * Copy the new maximum trace into the separate maximum-trace
671 * structure. (this way the maximum trace is permanently saved,
672 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
675 __update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
677 struct trace_array_cpu
*data
= tr
->data
[cpu
];
678 struct trace_array_cpu
*max_data
;
681 max_tr
.time_start
= data
->preempt_timestamp
;
683 max_data
= max_tr
.data
[cpu
];
684 max_data
->saved_latency
= tracing_max_latency
;
685 max_data
->critical_start
= data
->critical_start
;
686 max_data
->critical_end
= data
->critical_end
;
688 memcpy(max_data
->comm
, tsk
->comm
, TASK_COMM_LEN
);
689 max_data
->pid
= tsk
->pid
;
690 max_data
->uid
= task_uid(tsk
);
691 max_data
->nice
= tsk
->static_prio
- 20 - MAX_RT_PRIO
;
692 max_data
->policy
= tsk
->policy
;
693 max_data
->rt_priority
= tsk
->rt_priority
;
695 /* record this tasks comm */
696 tracing_record_cmdline(tsk
);
700 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
702 * @tsk: the task with the latency
703 * @cpu: The cpu that initiated the trace.
705 * Flip the buffers between the @tr and the max_tr and record information
706 * about which task was the cause of this latency.
709 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
711 struct ring_buffer
*buf
= tr
->buffer
;
713 if (trace_stop_count
)
716 WARN_ON_ONCE(!irqs_disabled());
717 if (!current_trace
->use_max_tr
) {
721 arch_spin_lock(&ftrace_max_lock
);
723 tr
->buffer
= max_tr
.buffer
;
726 __update_max_tr(tr
, tsk
, cpu
);
727 arch_spin_unlock(&ftrace_max_lock
);
731 * update_max_tr_single - only copy one trace over, and reset the rest
733 * @tsk - task with the latency
734 * @cpu - the cpu of the buffer to copy.
736 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
739 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
743 if (trace_stop_count
)
746 WARN_ON_ONCE(!irqs_disabled());
747 if (!current_trace
->use_max_tr
) {
752 arch_spin_lock(&ftrace_max_lock
);
754 ftrace_disable_cpu();
756 ret
= ring_buffer_swap_cpu(max_tr
.buffer
, tr
->buffer
, cpu
);
760 * We failed to swap the buffer due to a commit taking
761 * place on this CPU. We fail to record, but we reset
762 * the max trace buffer (no one writes directly to it)
763 * and flag that it failed.
765 trace_array_printk(&max_tr
, _THIS_IP_
,
766 "Failed to swap buffers due to commit in progress\n");
771 WARN_ON_ONCE(ret
&& ret
!= -EAGAIN
&& ret
!= -EBUSY
);
773 __update_max_tr(tr
, tsk
, cpu
);
774 arch_spin_unlock(&ftrace_max_lock
);
776 #endif /* CONFIG_TRACER_MAX_TRACE */
779 * register_tracer - register a tracer with the ftrace system.
780 * @type - the plugin for the tracer
782 * Register a new plugin tracer.
784 int register_tracer(struct tracer
*type
)
785 __releases(kernel_lock
)
786 __acquires(kernel_lock
)
792 pr_info("Tracer must have a name\n");
796 if (strlen(type
->name
) >= MAX_TRACER_SIZE
) {
797 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE
);
801 mutex_lock(&trace_types_lock
);
803 tracing_selftest_running
= true;
805 for (t
= trace_types
; t
; t
= t
->next
) {
806 if (strcmp(type
->name
, t
->name
) == 0) {
808 pr_info("Tracer %s already registered\n",
816 type
->set_flag
= &dummy_set_flag
;
818 type
->flags
= &dummy_tracer_flags
;
820 if (!type
->flags
->opts
)
821 type
->flags
->opts
= dummy_tracer_opt
;
822 if (!type
->wait_pipe
)
823 type
->wait_pipe
= default_wait_pipe
;
826 #ifdef CONFIG_FTRACE_STARTUP_TEST
827 if (type
->selftest
&& !tracing_selftest_disabled
) {
828 struct tracer
*saved_tracer
= current_trace
;
829 struct trace_array
*tr
= &global_trace
;
832 * Run a selftest on this tracer.
833 * Here we reset the trace buffer, and set the current
834 * tracer to be this tracer. The tracer can then run some
835 * internal tracing to verify that everything is in order.
836 * If we fail, we do not register this tracer.
838 tracing_reset_online_cpus(tr
);
840 current_trace
= type
;
842 /* If we expanded the buffers, make sure the max is expanded too */
843 if (ring_buffer_expanded
&& type
->use_max_tr
)
844 ring_buffer_resize(max_tr
.buffer
, trace_buf_size
);
846 /* the test is responsible for initializing and enabling */
847 pr_info("Testing tracer %s: ", type
->name
);
848 ret
= type
->selftest(type
, tr
);
849 /* the test is responsible for resetting too */
850 current_trace
= saved_tracer
;
852 printk(KERN_CONT
"FAILED!\n");
855 /* Only reset on passing, to avoid touching corrupted buffers */
856 tracing_reset_online_cpus(tr
);
858 /* Shrink the max buffer again */
859 if (ring_buffer_expanded
&& type
->use_max_tr
)
860 ring_buffer_resize(max_tr
.buffer
, 1);
862 printk(KERN_CONT
"PASSED\n");
866 type
->next
= trace_types
;
870 tracing_selftest_running
= false;
871 mutex_unlock(&trace_types_lock
);
873 if (ret
|| !default_bootup_tracer
)
876 if (strncmp(default_bootup_tracer
, type
->name
, MAX_TRACER_SIZE
))
879 printk(KERN_INFO
"Starting tracer '%s'\n", type
->name
);
880 /* Do we want this tracer to start on bootup? */
881 tracing_set_tracer(type
->name
);
882 default_bootup_tracer
= NULL
;
883 /* disable other selftests, since this will break it. */
884 tracing_selftest_disabled
= 1;
885 #ifdef CONFIG_FTRACE_STARTUP_TEST
886 printk(KERN_INFO
"Disabling FTRACE selftests due to running tracer '%s'\n",
894 void unregister_tracer(struct tracer
*type
)
898 mutex_lock(&trace_types_lock
);
899 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
903 pr_info("Tracer %s not registered\n", type
->name
);
909 if (type
== current_trace
&& tracer_enabled
) {
912 if (current_trace
->stop
)
913 current_trace
->stop(&global_trace
);
914 current_trace
= &nop_trace
;
917 mutex_unlock(&trace_types_lock
);
920 static void __tracing_reset(struct ring_buffer
*buffer
, int cpu
)
922 ftrace_disable_cpu();
923 ring_buffer_reset_cpu(buffer
, cpu
);
927 void tracing_reset(struct trace_array
*tr
, int cpu
)
929 struct ring_buffer
*buffer
= tr
->buffer
;
931 ring_buffer_record_disable(buffer
);
933 /* Make sure all commits have finished */
935 __tracing_reset(buffer
, cpu
);
937 ring_buffer_record_enable(buffer
);
940 void tracing_reset_online_cpus(struct trace_array
*tr
)
942 struct ring_buffer
*buffer
= tr
->buffer
;
945 ring_buffer_record_disable(buffer
);
947 /* Make sure all commits have finished */
950 tr
->time_start
= ftrace_now(tr
->cpu
);
952 for_each_online_cpu(cpu
)
953 __tracing_reset(buffer
, cpu
);
955 ring_buffer_record_enable(buffer
);
958 void tracing_reset_current(int cpu
)
960 tracing_reset(&global_trace
, cpu
);
963 void tracing_reset_current_online_cpus(void)
965 tracing_reset_online_cpus(&global_trace
);
968 #define SAVED_CMDLINES 128
969 #define NO_CMDLINE_MAP UINT_MAX
970 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
971 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
972 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
973 static int cmdline_idx
;
974 static arch_spinlock_t trace_cmdline_lock
= __ARCH_SPIN_LOCK_UNLOCKED
;
976 /* temporary disable recording */
977 static atomic_t trace_record_cmdline_disabled __read_mostly
;
979 static void trace_init_cmdlines(void)
981 memset(&map_pid_to_cmdline
, NO_CMDLINE_MAP
, sizeof(map_pid_to_cmdline
));
982 memset(&map_cmdline_to_pid
, NO_CMDLINE_MAP
, sizeof(map_cmdline_to_pid
));
986 int is_tracing_stopped(void)
988 return trace_stop_count
;
992 * ftrace_off_permanent - disable all ftrace code permanently
994 * This should only be called when a serious anomally has
995 * been detected. This will turn off the function tracing,
996 * ring buffers, and other tracing utilites. It takes no
997 * locks and can be called from any context.
999 void ftrace_off_permanent(void)
1001 tracing_disabled
= 1;
1003 tracing_off_permanent();
1007 * tracing_start - quick start of the tracer
1009 * If tracing is enabled but was stopped by tracing_stop,
1010 * this will start the tracer back up.
1012 void tracing_start(void)
1014 struct ring_buffer
*buffer
;
1015 unsigned long flags
;
1017 if (tracing_disabled
)
1020 raw_spin_lock_irqsave(&tracing_start_lock
, flags
);
1021 if (--trace_stop_count
) {
1022 if (trace_stop_count
< 0) {
1023 /* Someone screwed up their debugging */
1025 trace_stop_count
= 0;
1030 /* Prevent the buffers from switching */
1031 arch_spin_lock(&ftrace_max_lock
);
1033 buffer
= global_trace
.buffer
;
1035 ring_buffer_record_enable(buffer
);
1037 buffer
= max_tr
.buffer
;
1039 ring_buffer_record_enable(buffer
);
1041 arch_spin_unlock(&ftrace_max_lock
);
1045 raw_spin_unlock_irqrestore(&tracing_start_lock
, flags
);
1049 * tracing_stop - quick stop of the tracer
1051 * Light weight way to stop tracing. Use in conjunction with
1054 void tracing_stop(void)
1056 struct ring_buffer
*buffer
;
1057 unsigned long flags
;
1060 raw_spin_lock_irqsave(&tracing_start_lock
, flags
);
1061 if (trace_stop_count
++)
1064 /* Prevent the buffers from switching */
1065 arch_spin_lock(&ftrace_max_lock
);
1067 buffer
= global_trace
.buffer
;
1069 ring_buffer_record_disable(buffer
);
1071 buffer
= max_tr
.buffer
;
1073 ring_buffer_record_disable(buffer
);
1075 arch_spin_unlock(&ftrace_max_lock
);
1078 raw_spin_unlock_irqrestore(&tracing_start_lock
, flags
);
1081 void trace_stop_cmdline_recording(void);
1083 static void trace_save_cmdline(struct task_struct
*tsk
)
1087 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
1091 * It's not the end of the world if we don't get
1092 * the lock, but we also don't want to spin
1093 * nor do we want to disable interrupts,
1094 * so if we miss here, then better luck next time.
1096 if (!arch_spin_trylock(&trace_cmdline_lock
))
1099 idx
= map_pid_to_cmdline
[tsk
->pid
];
1100 if (idx
== NO_CMDLINE_MAP
) {
1101 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
1104 * Check whether the cmdline buffer at idx has a pid
1105 * mapped. We are going to overwrite that entry so we
1106 * need to clear the map_pid_to_cmdline. Otherwise we
1107 * would read the new comm for the old pid.
1109 pid
= map_cmdline_to_pid
[idx
];
1110 if (pid
!= NO_CMDLINE_MAP
)
1111 map_pid_to_cmdline
[pid
] = NO_CMDLINE_MAP
;
1113 map_cmdline_to_pid
[idx
] = tsk
->pid
;
1114 map_pid_to_cmdline
[tsk
->pid
] = idx
;
1119 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
1121 arch_spin_unlock(&trace_cmdline_lock
);
1124 void trace_find_cmdline(int pid
, char comm
[])
1129 strcpy(comm
, "<idle>");
1133 if (WARN_ON_ONCE(pid
< 0)) {
1134 strcpy(comm
, "<XXX>");
1138 if (pid
> PID_MAX_DEFAULT
) {
1139 strcpy(comm
, "<...>");
1144 arch_spin_lock(&trace_cmdline_lock
);
1145 map
= map_pid_to_cmdline
[pid
];
1146 if (map
!= NO_CMDLINE_MAP
)
1147 strcpy(comm
, saved_cmdlines
[map
]);
1149 strcpy(comm
, "<...>");
1151 arch_spin_unlock(&trace_cmdline_lock
);
1155 void tracing_record_cmdline(struct task_struct
*tsk
)
1157 if (atomic_read(&trace_record_cmdline_disabled
) || !tracer_enabled
||
1161 trace_save_cmdline(tsk
);
1165 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
,
1168 struct task_struct
*tsk
= current
;
1170 entry
->preempt_count
= pc
& 0xff;
1171 entry
->pid
= (tsk
) ? tsk
->pid
: 0;
1174 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1175 (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
1177 TRACE_FLAG_IRQS_NOSUPPORT
|
1179 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
1180 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
1181 (need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0);
1183 EXPORT_SYMBOL_GPL(tracing_generic_entry_update
);
1185 struct ring_buffer_event
*
1186 trace_buffer_lock_reserve(struct ring_buffer
*buffer
,
1189 unsigned long flags
, int pc
)
1191 struct ring_buffer_event
*event
;
1193 event
= ring_buffer_lock_reserve(buffer
, len
);
1194 if (event
!= NULL
) {
1195 struct trace_entry
*ent
= ring_buffer_event_data(event
);
1197 tracing_generic_entry_update(ent
, flags
, pc
);
1205 __trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1206 struct ring_buffer_event
*event
,
1207 unsigned long flags
, int pc
,
1210 ring_buffer_unlock_commit(buffer
, event
);
1212 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1213 ftrace_trace_userstack(buffer
, flags
, pc
);
1219 void trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1220 struct ring_buffer_event
*event
,
1221 unsigned long flags
, int pc
)
1223 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
, 1);
1226 struct ring_buffer_event
*
1227 trace_current_buffer_lock_reserve(struct ring_buffer
**current_rb
,
1228 int type
, unsigned long len
,
1229 unsigned long flags
, int pc
)
1231 *current_rb
= global_trace
.buffer
;
1232 return trace_buffer_lock_reserve(*current_rb
,
1233 type
, len
, flags
, pc
);
1235 EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve
);
1237 void trace_current_buffer_unlock_commit(struct ring_buffer
*buffer
,
1238 struct ring_buffer_event
*event
,
1239 unsigned long flags
, int pc
)
1241 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
, 1);
1243 EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit
);
1245 void trace_nowake_buffer_unlock_commit(struct ring_buffer
*buffer
,
1246 struct ring_buffer_event
*event
,
1247 unsigned long flags
, int pc
)
1249 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
, 0);
1251 EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit
);
1253 void trace_nowake_buffer_unlock_commit_regs(struct ring_buffer
*buffer
,
1254 struct ring_buffer_event
*event
,
1255 unsigned long flags
, int pc
,
1256 struct pt_regs
*regs
)
1258 ring_buffer_unlock_commit(buffer
, event
);
1260 ftrace_trace_stack_regs(buffer
, flags
, 0, pc
, regs
);
1261 ftrace_trace_userstack(buffer
, flags
, pc
);
1263 EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit_regs
);
1265 void trace_current_buffer_discard_commit(struct ring_buffer
*buffer
,
1266 struct ring_buffer_event
*event
)
1268 ring_buffer_discard_commit(buffer
, event
);
1270 EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit
);
1273 trace_function(struct trace_array
*tr
,
1274 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
1277 struct ftrace_event_call
*call
= &event_function
;
1278 struct ring_buffer
*buffer
= tr
->buffer
;
1279 struct ring_buffer_event
*event
;
1280 struct ftrace_entry
*entry
;
1282 /* If we are reading the ring buffer, don't trace */
1283 if (unlikely(__this_cpu_read(ftrace_cpu_disabled
)))
1286 event
= trace_buffer_lock_reserve(buffer
, TRACE_FN
, sizeof(*entry
),
1290 entry
= ring_buffer_event_data(event
);
1292 entry
->parent_ip
= parent_ip
;
1294 if (!filter_check_discard(call
, entry
, buffer
, event
))
1295 ring_buffer_unlock_commit(buffer
, event
);
1299 ftrace(struct trace_array
*tr
, struct trace_array_cpu
*data
,
1300 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
1303 if (likely(!atomic_read(&data
->disabled
)))
1304 trace_function(tr
, ip
, parent_ip
, flags
, pc
);
1307 #ifdef CONFIG_STACKTRACE
1309 #define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
1310 struct ftrace_stack
{
1311 unsigned long calls
[FTRACE_STACK_MAX_ENTRIES
];
1314 static DEFINE_PER_CPU(struct ftrace_stack
, ftrace_stack
);
1315 static DEFINE_PER_CPU(int, ftrace_stack_reserve
);
1317 static void __ftrace_trace_stack(struct ring_buffer
*buffer
,
1318 unsigned long flags
,
1319 int skip
, int pc
, struct pt_regs
*regs
)
1321 struct ftrace_event_call
*call
= &event_kernel_stack
;
1322 struct ring_buffer_event
*event
;
1323 struct stack_entry
*entry
;
1324 struct stack_trace trace
;
1326 int size
= FTRACE_STACK_ENTRIES
;
1328 trace
.nr_entries
= 0;
1332 * Since events can happen in NMIs there's no safe way to
1333 * use the per cpu ftrace_stacks. We reserve it and if an interrupt
1334 * or NMI comes in, it will just have to use the default
1335 * FTRACE_STACK_SIZE.
1337 preempt_disable_notrace();
1339 use_stack
= ++__get_cpu_var(ftrace_stack_reserve
);
1341 * We don't need any atomic variables, just a barrier.
1342 * If an interrupt comes in, we don't care, because it would
1343 * have exited and put the counter back to what we want.
1344 * We just need a barrier to keep gcc from moving things
1348 if (use_stack
== 1) {
1349 trace
.entries
= &__get_cpu_var(ftrace_stack
).calls
[0];
1350 trace
.max_entries
= FTRACE_STACK_MAX_ENTRIES
;
1353 save_stack_trace_regs(regs
, &trace
);
1355 save_stack_trace(&trace
);
1357 if (trace
.nr_entries
> size
)
1358 size
= trace
.nr_entries
;
1360 /* From now on, use_stack is a boolean */
1363 size
*= sizeof(unsigned long);
1365 event
= trace_buffer_lock_reserve(buffer
, TRACE_STACK
,
1366 sizeof(*entry
) + size
, flags
, pc
);
1369 entry
= ring_buffer_event_data(event
);
1371 memset(&entry
->caller
, 0, size
);
1374 memcpy(&entry
->caller
, trace
.entries
,
1375 trace
.nr_entries
* sizeof(unsigned long));
1377 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1378 trace
.entries
= entry
->caller
;
1380 save_stack_trace_regs(regs
, &trace
);
1382 save_stack_trace(&trace
);
1385 entry
->size
= trace
.nr_entries
;
1387 if (!filter_check_discard(call
, entry
, buffer
, event
))
1388 ring_buffer_unlock_commit(buffer
, event
);
1391 /* Again, don't let gcc optimize things here */
1393 __get_cpu_var(ftrace_stack_reserve
)--;
1394 preempt_enable_notrace();
1398 void ftrace_trace_stack_regs(struct ring_buffer
*buffer
, unsigned long flags
,
1399 int skip
, int pc
, struct pt_regs
*regs
)
1401 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1404 __ftrace_trace_stack(buffer
, flags
, skip
, pc
, regs
);
1407 void ftrace_trace_stack(struct ring_buffer
*buffer
, unsigned long flags
,
1410 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1413 __ftrace_trace_stack(buffer
, flags
, skip
, pc
, NULL
);
1416 void __trace_stack(struct trace_array
*tr
, unsigned long flags
, int skip
,
1419 __ftrace_trace_stack(tr
->buffer
, flags
, skip
, pc
, NULL
);
1423 * trace_dump_stack - record a stack back trace in the trace buffer
1425 void trace_dump_stack(void)
1427 unsigned long flags
;
1429 if (tracing_disabled
|| tracing_selftest_running
)
1432 local_save_flags(flags
);
1434 /* skipping 3 traces, seems to get us at the caller of this function */
1435 __ftrace_trace_stack(global_trace
.buffer
, flags
, 3, preempt_count(), NULL
);
1438 static DEFINE_PER_CPU(int, user_stack_count
);
1441 ftrace_trace_userstack(struct ring_buffer
*buffer
, unsigned long flags
, int pc
)
1443 struct ftrace_event_call
*call
= &event_user_stack
;
1444 struct ring_buffer_event
*event
;
1445 struct userstack_entry
*entry
;
1446 struct stack_trace trace
;
1448 if (!(trace_flags
& TRACE_ITER_USERSTACKTRACE
))
1452 * NMIs can not handle page faults, even with fix ups.
1453 * The save user stack can (and often does) fault.
1455 if (unlikely(in_nmi()))
1459 * prevent recursion, since the user stack tracing may
1460 * trigger other kernel events.
1463 if (__this_cpu_read(user_stack_count
))
1466 __this_cpu_inc(user_stack_count
);
1468 event
= trace_buffer_lock_reserve(buffer
, TRACE_USER_STACK
,
1469 sizeof(*entry
), flags
, pc
);
1471 goto out_drop_count
;
1472 entry
= ring_buffer_event_data(event
);
1474 entry
->tgid
= current
->tgid
;
1475 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
1477 trace
.nr_entries
= 0;
1478 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1480 trace
.entries
= entry
->caller
;
1482 save_stack_trace_user(&trace
);
1483 if (!filter_check_discard(call
, entry
, buffer
, event
))
1484 ring_buffer_unlock_commit(buffer
, event
);
1487 __this_cpu_dec(user_stack_count
);
1493 static void __trace_userstack(struct trace_array
*tr
, unsigned long flags
)
1495 ftrace_trace_userstack(tr
, flags
, preempt_count());
1499 #endif /* CONFIG_STACKTRACE */
1502 * trace_vbprintk - write binary msg to tracing buffer
1505 int trace_vbprintk(unsigned long ip
, const char *fmt
, va_list args
)
1507 static arch_spinlock_t trace_buf_lock
=
1508 (arch_spinlock_t
)__ARCH_SPIN_LOCK_UNLOCKED
;
1509 static u32 trace_buf
[TRACE_BUF_SIZE
];
1511 struct ftrace_event_call
*call
= &event_bprint
;
1512 struct ring_buffer_event
*event
;
1513 struct ring_buffer
*buffer
;
1514 struct trace_array
*tr
= &global_trace
;
1515 struct trace_array_cpu
*data
;
1516 struct bprint_entry
*entry
;
1517 unsigned long flags
;
1519 int cpu
, len
= 0, size
, pc
;
1521 if (unlikely(tracing_selftest_running
|| tracing_disabled
))
1524 /* Don't pollute graph traces with trace_vprintk internals */
1525 pause_graph_tracing();
1527 pc
= preempt_count();
1528 preempt_disable_notrace();
1529 cpu
= raw_smp_processor_id();
1530 data
= tr
->data
[cpu
];
1532 disable
= atomic_inc_return(&data
->disabled
);
1533 if (unlikely(disable
!= 1))
1536 /* Lockdep uses trace_printk for lock tracing */
1537 local_irq_save(flags
);
1538 arch_spin_lock(&trace_buf_lock
);
1539 len
= vbin_printf(trace_buf
, TRACE_BUF_SIZE
, fmt
, args
);
1541 if (len
> TRACE_BUF_SIZE
|| len
< 0)
1544 size
= sizeof(*entry
) + sizeof(u32
) * len
;
1545 buffer
= tr
->buffer
;
1546 event
= trace_buffer_lock_reserve(buffer
, TRACE_BPRINT
, size
,
1550 entry
= ring_buffer_event_data(event
);
1554 memcpy(entry
->buf
, trace_buf
, sizeof(u32
) * len
);
1555 if (!filter_check_discard(call
, entry
, buffer
, event
)) {
1556 ring_buffer_unlock_commit(buffer
, event
);
1557 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1561 arch_spin_unlock(&trace_buf_lock
);
1562 local_irq_restore(flags
);
1565 atomic_dec_return(&data
->disabled
);
1566 preempt_enable_notrace();
1567 unpause_graph_tracing();
1571 EXPORT_SYMBOL_GPL(trace_vbprintk
);
1573 int trace_array_printk(struct trace_array
*tr
,
1574 unsigned long ip
, const char *fmt
, ...)
1579 if (!(trace_flags
& TRACE_ITER_PRINTK
))
1583 ret
= trace_array_vprintk(tr
, ip
, fmt
, ap
);
1588 int trace_array_vprintk(struct trace_array
*tr
,
1589 unsigned long ip
, const char *fmt
, va_list args
)
1591 static arch_spinlock_t trace_buf_lock
= __ARCH_SPIN_LOCK_UNLOCKED
;
1592 static char trace_buf
[TRACE_BUF_SIZE
];
1594 struct ftrace_event_call
*call
= &event_print
;
1595 struct ring_buffer_event
*event
;
1596 struct ring_buffer
*buffer
;
1597 struct trace_array_cpu
*data
;
1598 int cpu
, len
= 0, size
, pc
;
1599 struct print_entry
*entry
;
1600 unsigned long irq_flags
;
1603 if (tracing_disabled
|| tracing_selftest_running
)
1606 pc
= preempt_count();
1607 preempt_disable_notrace();
1608 cpu
= raw_smp_processor_id();
1609 data
= tr
->data
[cpu
];
1611 disable
= atomic_inc_return(&data
->disabled
);
1612 if (unlikely(disable
!= 1))
1615 pause_graph_tracing();
1616 raw_local_irq_save(irq_flags
);
1617 arch_spin_lock(&trace_buf_lock
);
1618 len
= vsnprintf(trace_buf
, TRACE_BUF_SIZE
, fmt
, args
);
1620 size
= sizeof(*entry
) + len
+ 1;
1621 buffer
= tr
->buffer
;
1622 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, size
,
1626 entry
= ring_buffer_event_data(event
);
1629 memcpy(&entry
->buf
, trace_buf
, len
);
1630 entry
->buf
[len
] = '\0';
1631 if (!filter_check_discard(call
, entry
, buffer
, event
)) {
1632 ring_buffer_unlock_commit(buffer
, event
);
1633 ftrace_trace_stack(buffer
, irq_flags
, 6, pc
);
1637 arch_spin_unlock(&trace_buf_lock
);
1638 raw_local_irq_restore(irq_flags
);
1639 unpause_graph_tracing();
1641 atomic_dec_return(&data
->disabled
);
1642 preempt_enable_notrace();
1647 int trace_vprintk(unsigned long ip
, const char *fmt
, va_list args
)
1649 return trace_array_vprintk(&global_trace
, ip
, fmt
, args
);
1651 EXPORT_SYMBOL_GPL(trace_vprintk
);
1653 static void trace_iterator_increment(struct trace_iterator
*iter
)
1655 /* Don't allow ftrace to trace into the ring buffers */
1656 ftrace_disable_cpu();
1659 if (iter
->buffer_iter
[iter
->cpu
])
1660 ring_buffer_read(iter
->buffer_iter
[iter
->cpu
], NULL
);
1662 ftrace_enable_cpu();
1665 static struct trace_entry
*
1666 peek_next_entry(struct trace_iterator
*iter
, int cpu
, u64
*ts
,
1667 unsigned long *lost_events
)
1669 struct ring_buffer_event
*event
;
1670 struct ring_buffer_iter
*buf_iter
= iter
->buffer_iter
[cpu
];
1672 /* Don't allow ftrace to trace into the ring buffers */
1673 ftrace_disable_cpu();
1676 event
= ring_buffer_iter_peek(buf_iter
, ts
);
1678 event
= ring_buffer_peek(iter
->tr
->buffer
, cpu
, ts
,
1681 ftrace_enable_cpu();
1684 iter
->ent_size
= ring_buffer_event_length(event
);
1685 return ring_buffer_event_data(event
);
1691 static struct trace_entry
*
1692 __find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
,
1693 unsigned long *missing_events
, u64
*ent_ts
)
1695 struct ring_buffer
*buffer
= iter
->tr
->buffer
;
1696 struct trace_entry
*ent
, *next
= NULL
;
1697 unsigned long lost_events
= 0, next_lost
= 0;
1698 int cpu_file
= iter
->cpu_file
;
1699 u64 next_ts
= 0, ts
;
1705 * If we are in a per_cpu trace file, don't bother by iterating over
1706 * all cpu and peek directly.
1708 if (cpu_file
> TRACE_PIPE_ALL_CPU
) {
1709 if (ring_buffer_empty_cpu(buffer
, cpu_file
))
1711 ent
= peek_next_entry(iter
, cpu_file
, ent_ts
, missing_events
);
1713 *ent_cpu
= cpu_file
;
1718 for_each_tracing_cpu(cpu
) {
1720 if (ring_buffer_empty_cpu(buffer
, cpu
))
1723 ent
= peek_next_entry(iter
, cpu
, &ts
, &lost_events
);
1726 * Pick the entry with the smallest timestamp:
1728 if (ent
&& (!next
|| ts
< next_ts
)) {
1732 next_lost
= lost_events
;
1733 next_size
= iter
->ent_size
;
1737 iter
->ent_size
= next_size
;
1740 *ent_cpu
= next_cpu
;
1746 *missing_events
= next_lost
;
1751 /* Find the next real entry, without updating the iterator itself */
1752 struct trace_entry
*trace_find_next_entry(struct trace_iterator
*iter
,
1753 int *ent_cpu
, u64
*ent_ts
)
1755 return __find_next_entry(iter
, ent_cpu
, NULL
, ent_ts
);
1758 /* Find the next real entry, and increment the iterator to the next entry */
1759 void *trace_find_next_entry_inc(struct trace_iterator
*iter
)
1761 iter
->ent
= __find_next_entry(iter
, &iter
->cpu
,
1762 &iter
->lost_events
, &iter
->ts
);
1765 trace_iterator_increment(iter
);
1767 return iter
->ent
? iter
: NULL
;
1770 static void trace_consume(struct trace_iterator
*iter
)
1772 /* Don't allow ftrace to trace into the ring buffers */
1773 ftrace_disable_cpu();
1774 ring_buffer_consume(iter
->tr
->buffer
, iter
->cpu
, &iter
->ts
,
1775 &iter
->lost_events
);
1776 ftrace_enable_cpu();
1779 static void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1781 struct trace_iterator
*iter
= m
->private;
1785 WARN_ON_ONCE(iter
->leftover
);
1789 /* can't go backwards */
1794 ent
= trace_find_next_entry_inc(iter
);
1798 while (ent
&& iter
->idx
< i
)
1799 ent
= trace_find_next_entry_inc(iter
);
1806 void tracing_iter_reset(struct trace_iterator
*iter
, int cpu
)
1808 struct trace_array
*tr
= iter
->tr
;
1809 struct ring_buffer_event
*event
;
1810 struct ring_buffer_iter
*buf_iter
;
1811 unsigned long entries
= 0;
1814 tr
->data
[cpu
]->skipped_entries
= 0;
1816 if (!iter
->buffer_iter
[cpu
])
1819 buf_iter
= iter
->buffer_iter
[cpu
];
1820 ring_buffer_iter_reset(buf_iter
);
1823 * We could have the case with the max latency tracers
1824 * that a reset never took place on a cpu. This is evident
1825 * by the timestamp being before the start of the buffer.
1827 while ((event
= ring_buffer_iter_peek(buf_iter
, &ts
))) {
1828 if (ts
>= iter
->tr
->time_start
)
1831 ring_buffer_read(buf_iter
, NULL
);
1834 tr
->data
[cpu
]->skipped_entries
= entries
;
1838 * The current tracer is copied to avoid a global locking
1841 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
1843 struct trace_iterator
*iter
= m
->private;
1844 static struct tracer
*old_tracer
;
1845 int cpu_file
= iter
->cpu_file
;
1850 /* copy the tracer to avoid using a global lock all around */
1851 mutex_lock(&trace_types_lock
);
1852 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
1853 old_tracer
= current_trace
;
1854 *iter
->trace
= *current_trace
;
1856 mutex_unlock(&trace_types_lock
);
1858 atomic_inc(&trace_record_cmdline_disabled
);
1860 if (*pos
!= iter
->pos
) {
1865 ftrace_disable_cpu();
1867 if (cpu_file
== TRACE_PIPE_ALL_CPU
) {
1868 for_each_tracing_cpu(cpu
)
1869 tracing_iter_reset(iter
, cpu
);
1871 tracing_iter_reset(iter
, cpu_file
);
1873 ftrace_enable_cpu();
1876 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
1881 * If we overflowed the seq_file before, then we want
1882 * to just reuse the trace_seq buffer again.
1888 p
= s_next(m
, p
, &l
);
1892 trace_event_read_lock();
1893 trace_access_lock(cpu_file
);
1897 static void s_stop(struct seq_file
*m
, void *p
)
1899 struct trace_iterator
*iter
= m
->private;
1901 atomic_dec(&trace_record_cmdline_disabled
);
1902 trace_access_unlock(iter
->cpu_file
);
1903 trace_event_read_unlock();
1907 get_total_entries(struct trace_array
*tr
, unsigned long *total
, unsigned long *entries
)
1909 unsigned long count
;
1915 for_each_tracing_cpu(cpu
) {
1916 count
= ring_buffer_entries_cpu(tr
->buffer
, cpu
);
1918 * If this buffer has skipped entries, then we hold all
1919 * entries for the trace and we need to ignore the
1920 * ones before the time stamp.
1922 if (tr
->data
[cpu
]->skipped_entries
) {
1923 count
-= tr
->data
[cpu
]->skipped_entries
;
1924 /* total is the same as the entries */
1928 ring_buffer_overrun_cpu(tr
->buffer
, cpu
);
1933 static void print_lat_help_header(struct seq_file
*m
)
1935 seq_puts(m
, "# _------=> CPU# \n");
1936 seq_puts(m
, "# / _-----=> irqs-off \n");
1937 seq_puts(m
, "# | / _----=> need-resched \n");
1938 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
1939 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
1940 seq_puts(m
, "# |||| / delay \n");
1941 seq_puts(m
, "# cmd pid ||||| time | caller \n");
1942 seq_puts(m
, "# \\ / ||||| \\ | / \n");
1945 static void print_event_info(struct trace_array
*tr
, struct seq_file
*m
)
1947 unsigned long total
;
1948 unsigned long entries
;
1950 get_total_entries(tr
, &total
, &entries
);
1951 seq_printf(m
, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
1952 entries
, total
, num_online_cpus());
1956 static void print_func_help_header(struct trace_array
*tr
, struct seq_file
*m
)
1958 print_event_info(tr
, m
);
1959 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1960 seq_puts(m
, "# | | | | |\n");
1963 static void print_func_help_header_irq(struct trace_array
*tr
, struct seq_file
*m
)
1965 print_event_info(tr
, m
);
1966 seq_puts(m
, "# _-----=> irqs-off\n");
1967 seq_puts(m
, "# / _----=> need-resched\n");
1968 seq_puts(m
, "# | / _---=> hardirq/softirq\n");
1969 seq_puts(m
, "# || / _--=> preempt-depth\n");
1970 seq_puts(m
, "# ||| / delay\n");
1971 seq_puts(m
, "# TASK-PID CPU# |||| TIMESTAMP FUNCTION\n");
1972 seq_puts(m
, "# | | | |||| | |\n");
1976 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
1978 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1979 struct trace_array
*tr
= iter
->tr
;
1980 struct trace_array_cpu
*data
= tr
->data
[tr
->cpu
];
1981 struct tracer
*type
= current_trace
;
1982 unsigned long entries
;
1983 unsigned long total
;
1984 const char *name
= "preemption";
1989 get_total_entries(tr
, &total
, &entries
);
1991 seq_printf(m
, "# %s latency trace v1.1.5 on %s\n",
1993 seq_puts(m
, "# -----------------------------------"
1994 "---------------------------------\n");
1995 seq_printf(m
, "# latency: %lu us, #%lu/%lu, CPU#%d |"
1996 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1997 nsecs_to_usecs(data
->saved_latency
),
2001 #if defined(CONFIG_PREEMPT_NONE)
2003 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
2005 #elif defined(CONFIG_PREEMPT)
2010 /* These are reserved for later use */
2013 seq_printf(m
, " #P:%d)\n", num_online_cpus());
2017 seq_puts(m
, "# -----------------\n");
2018 seq_printf(m
, "# | task: %.16s-%d "
2019 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
2020 data
->comm
, data
->pid
, data
->uid
, data
->nice
,
2021 data
->policy
, data
->rt_priority
);
2022 seq_puts(m
, "# -----------------\n");
2024 if (data
->critical_start
) {
2025 seq_puts(m
, "# => started at: ");
2026 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
2027 trace_print_seq(m
, &iter
->seq
);
2028 seq_puts(m
, "\n# => ended at: ");
2029 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
2030 trace_print_seq(m
, &iter
->seq
);
2031 seq_puts(m
, "\n#\n");
2037 static void test_cpu_buff_start(struct trace_iterator
*iter
)
2039 struct trace_seq
*s
= &iter
->seq
;
2041 if (!(trace_flags
& TRACE_ITER_ANNOTATE
))
2044 if (!(iter
->iter_flags
& TRACE_FILE_ANNOTATE
))
2047 if (cpumask_test_cpu(iter
->cpu
, iter
->started
))
2050 if (iter
->tr
->data
[iter
->cpu
]->skipped_entries
)
2053 cpumask_set_cpu(iter
->cpu
, iter
->started
);
2055 /* Don't print started cpu buffer for the first entry of the trace */
2057 trace_seq_printf(s
, "##### CPU %u buffer started ####\n",
2061 static enum print_line_t
print_trace_fmt(struct trace_iterator
*iter
)
2063 struct trace_seq
*s
= &iter
->seq
;
2064 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
2065 struct trace_entry
*entry
;
2066 struct trace_event
*event
;
2070 test_cpu_buff_start(iter
);
2072 event
= ftrace_find_event(entry
->type
);
2074 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2075 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
2076 if (!trace_print_lat_context(iter
))
2079 if (!trace_print_context(iter
))
2085 return event
->funcs
->trace(iter
, sym_flags
, event
);
2087 if (!trace_seq_printf(s
, "Unknown type %d\n", entry
->type
))
2090 return TRACE_TYPE_HANDLED
;
2092 return TRACE_TYPE_PARTIAL_LINE
;
2095 static enum print_line_t
print_raw_fmt(struct trace_iterator
*iter
)
2097 struct trace_seq
*s
= &iter
->seq
;
2098 struct trace_entry
*entry
;
2099 struct trace_event
*event
;
2103 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2104 if (!trace_seq_printf(s
, "%d %d %llu ",
2105 entry
->pid
, iter
->cpu
, iter
->ts
))
2109 event
= ftrace_find_event(entry
->type
);
2111 return event
->funcs
->raw(iter
, 0, event
);
2113 if (!trace_seq_printf(s
, "%d ?\n", entry
->type
))
2116 return TRACE_TYPE_HANDLED
;
2118 return TRACE_TYPE_PARTIAL_LINE
;
2121 static enum print_line_t
print_hex_fmt(struct trace_iterator
*iter
)
2123 struct trace_seq
*s
= &iter
->seq
;
2124 unsigned char newline
= '\n';
2125 struct trace_entry
*entry
;
2126 struct trace_event
*event
;
2130 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2131 SEQ_PUT_HEX_FIELD_RET(s
, entry
->pid
);
2132 SEQ_PUT_HEX_FIELD_RET(s
, iter
->cpu
);
2133 SEQ_PUT_HEX_FIELD_RET(s
, iter
->ts
);
2136 event
= ftrace_find_event(entry
->type
);
2138 enum print_line_t ret
= event
->funcs
->hex(iter
, 0, event
);
2139 if (ret
!= TRACE_TYPE_HANDLED
)
2143 SEQ_PUT_FIELD_RET(s
, newline
);
2145 return TRACE_TYPE_HANDLED
;
2148 static enum print_line_t
print_bin_fmt(struct trace_iterator
*iter
)
2150 struct trace_seq
*s
= &iter
->seq
;
2151 struct trace_entry
*entry
;
2152 struct trace_event
*event
;
2156 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2157 SEQ_PUT_FIELD_RET(s
, entry
->pid
);
2158 SEQ_PUT_FIELD_RET(s
, iter
->cpu
);
2159 SEQ_PUT_FIELD_RET(s
, iter
->ts
);
2162 event
= ftrace_find_event(entry
->type
);
2163 return event
? event
->funcs
->binary(iter
, 0, event
) :
2167 int trace_empty(struct trace_iterator
*iter
)
2171 /* If we are looking at one CPU buffer, only check that one */
2172 if (iter
->cpu_file
!= TRACE_PIPE_ALL_CPU
) {
2173 cpu
= iter
->cpu_file
;
2174 if (iter
->buffer_iter
[cpu
]) {
2175 if (!ring_buffer_iter_empty(iter
->buffer_iter
[cpu
]))
2178 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
2184 for_each_tracing_cpu(cpu
) {
2185 if (iter
->buffer_iter
[cpu
]) {
2186 if (!ring_buffer_iter_empty(iter
->buffer_iter
[cpu
]))
2189 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
2197 /* Called with trace_event_read_lock() held. */
2198 enum print_line_t
print_trace_line(struct trace_iterator
*iter
)
2200 enum print_line_t ret
;
2202 if (iter
->lost_events
&&
2203 !trace_seq_printf(&iter
->seq
, "CPU:%d [LOST %lu EVENTS]\n",
2204 iter
->cpu
, iter
->lost_events
))
2205 return TRACE_TYPE_PARTIAL_LINE
;
2207 if (iter
->trace
&& iter
->trace
->print_line
) {
2208 ret
= iter
->trace
->print_line(iter
);
2209 if (ret
!= TRACE_TYPE_UNHANDLED
)
2213 if (iter
->ent
->type
== TRACE_BPRINT
&&
2214 trace_flags
& TRACE_ITER_PRINTK
&&
2215 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2216 return trace_print_bprintk_msg_only(iter
);
2218 if (iter
->ent
->type
== TRACE_PRINT
&&
2219 trace_flags
& TRACE_ITER_PRINTK
&&
2220 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2221 return trace_print_printk_msg_only(iter
);
2223 if (trace_flags
& TRACE_ITER_BIN
)
2224 return print_bin_fmt(iter
);
2226 if (trace_flags
& TRACE_ITER_HEX
)
2227 return print_hex_fmt(iter
);
2229 if (trace_flags
& TRACE_ITER_RAW
)
2230 return print_raw_fmt(iter
);
2232 return print_trace_fmt(iter
);
2235 void trace_latency_header(struct seq_file
*m
)
2237 struct trace_iterator
*iter
= m
->private;
2239 /* print nothing if the buffers are empty */
2240 if (trace_empty(iter
))
2243 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
)
2244 print_trace_header(m
, iter
);
2246 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2247 print_lat_help_header(m
);
2250 void trace_default_header(struct seq_file
*m
)
2252 struct trace_iterator
*iter
= m
->private;
2254 if (!(trace_flags
& TRACE_ITER_CONTEXT_INFO
))
2257 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
2258 /* print nothing if the buffers are empty */
2259 if (trace_empty(iter
))
2261 print_trace_header(m
, iter
);
2262 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2263 print_lat_help_header(m
);
2265 if (!(trace_flags
& TRACE_ITER_VERBOSE
)) {
2266 if (trace_flags
& TRACE_ITER_IRQ_INFO
)
2267 print_func_help_header_irq(iter
->tr
, m
);
2269 print_func_help_header(iter
->tr
, m
);
2274 static void test_ftrace_alive(struct seq_file
*m
)
2276 if (!ftrace_is_dead())
2278 seq_printf(m
, "# WARNING: FUNCTION TRACING IS CORRUPTED\n");
2279 seq_printf(m
, "# MAY BE MISSING FUNCTION EVENTS\n");
2282 static int s_show(struct seq_file
*m
, void *v
)
2284 struct trace_iterator
*iter
= v
;
2287 if (iter
->ent
== NULL
) {
2289 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
2291 test_ftrace_alive(m
);
2293 if (iter
->trace
&& iter
->trace
->print_header
)
2294 iter
->trace
->print_header(m
);
2296 trace_default_header(m
);
2298 } else if (iter
->leftover
) {
2300 * If we filled the seq_file buffer earlier, we
2301 * want to just show it now.
2303 ret
= trace_print_seq(m
, &iter
->seq
);
2305 /* ret should this time be zero, but you never know */
2306 iter
->leftover
= ret
;
2309 print_trace_line(iter
);
2310 ret
= trace_print_seq(m
, &iter
->seq
);
2312 * If we overflow the seq_file buffer, then it will
2313 * ask us for this data again at start up.
2315 * ret is 0 if seq_file write succeeded.
2318 iter
->leftover
= ret
;
2324 static const struct seq_operations tracer_seq_ops
= {
2331 static struct trace_iterator
*
2332 __tracing_open(struct inode
*inode
, struct file
*file
)
2334 long cpu_file
= (long) inode
->i_private
;
2335 void *fail_ret
= ERR_PTR(-ENOMEM
);
2336 struct trace_iterator
*iter
;
2340 if (tracing_disabled
)
2341 return ERR_PTR(-ENODEV
);
2343 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2345 return ERR_PTR(-ENOMEM
);
2348 * We make a copy of the current tracer to avoid concurrent
2349 * changes on it while we are reading.
2351 mutex_lock(&trace_types_lock
);
2352 iter
->trace
= kzalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
2357 *iter
->trace
= *current_trace
;
2359 if (!zalloc_cpumask_var(&iter
->started
, GFP_KERNEL
))
2362 if (current_trace
&& current_trace
->print_max
)
2365 iter
->tr
= &global_trace
;
2367 mutex_init(&iter
->mutex
);
2368 iter
->cpu_file
= cpu_file
;
2370 /* Notify the tracer early; before we stop tracing. */
2371 if (iter
->trace
&& iter
->trace
->open
)
2372 iter
->trace
->open(iter
);
2374 /* Annotate start of buffers if we had overruns */
2375 if (ring_buffer_overruns(iter
->tr
->buffer
))
2376 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
2378 /* stop the trace while dumping */
2381 if (iter
->cpu_file
== TRACE_PIPE_ALL_CPU
) {
2382 for_each_tracing_cpu(cpu
) {
2383 iter
->buffer_iter
[cpu
] =
2384 ring_buffer_read_prepare(iter
->tr
->buffer
, cpu
);
2386 ring_buffer_read_prepare_sync();
2387 for_each_tracing_cpu(cpu
) {
2388 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2389 tracing_iter_reset(iter
, cpu
);
2392 cpu
= iter
->cpu_file
;
2393 iter
->buffer_iter
[cpu
] =
2394 ring_buffer_read_prepare(iter
->tr
->buffer
, cpu
);
2395 ring_buffer_read_prepare_sync();
2396 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2397 tracing_iter_reset(iter
, cpu
);
2400 ret
= seq_open(file
, &tracer_seq_ops
);
2402 fail_ret
= ERR_PTR(ret
);
2406 m
= file
->private_data
;
2409 mutex_unlock(&trace_types_lock
);
2414 for_each_tracing_cpu(cpu
) {
2415 if (iter
->buffer_iter
[cpu
])
2416 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
2418 free_cpumask_var(iter
->started
);
2421 mutex_unlock(&trace_types_lock
);
2428 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
2430 if (tracing_disabled
)
2433 filp
->private_data
= inode
->i_private
;
2437 static int tracing_release(struct inode
*inode
, struct file
*file
)
2439 struct seq_file
*m
= file
->private_data
;
2440 struct trace_iterator
*iter
;
2443 if (!(file
->f_mode
& FMODE_READ
))
2448 mutex_lock(&trace_types_lock
);
2449 for_each_tracing_cpu(cpu
) {
2450 if (iter
->buffer_iter
[cpu
])
2451 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
2454 if (iter
->trace
&& iter
->trace
->close
)
2455 iter
->trace
->close(iter
);
2457 /* reenable tracing if it was previously enabled */
2459 mutex_unlock(&trace_types_lock
);
2461 seq_release(inode
, file
);
2462 mutex_destroy(&iter
->mutex
);
2463 free_cpumask_var(iter
->started
);
2469 static int tracing_open(struct inode
*inode
, struct file
*file
)
2471 struct trace_iterator
*iter
;
2474 /* If this file was open for write, then erase contents */
2475 if ((file
->f_mode
& FMODE_WRITE
) &&
2476 (file
->f_flags
& O_TRUNC
)) {
2477 long cpu
= (long) inode
->i_private
;
2479 if (cpu
== TRACE_PIPE_ALL_CPU
)
2480 tracing_reset_online_cpus(&global_trace
);
2482 tracing_reset(&global_trace
, cpu
);
2485 if (file
->f_mode
& FMODE_READ
) {
2486 iter
= __tracing_open(inode
, file
);
2488 ret
= PTR_ERR(iter
);
2489 else if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
2490 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
2496 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
2498 struct tracer
*t
= v
;
2508 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
2513 mutex_lock(&trace_types_lock
);
2514 for (t
= trace_types
; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
2520 static void t_stop(struct seq_file
*m
, void *p
)
2522 mutex_unlock(&trace_types_lock
);
2525 static int t_show(struct seq_file
*m
, void *v
)
2527 struct tracer
*t
= v
;
2532 seq_printf(m
, "%s", t
->name
);
2541 static const struct seq_operations show_traces_seq_ops
= {
2548 static int show_traces_open(struct inode
*inode
, struct file
*file
)
2550 if (tracing_disabled
)
2553 return seq_open(file
, &show_traces_seq_ops
);
2557 tracing_write_stub(struct file
*filp
, const char __user
*ubuf
,
2558 size_t count
, loff_t
*ppos
)
2563 static loff_t
tracing_seek(struct file
*file
, loff_t offset
, int origin
)
2565 if (file
->f_mode
& FMODE_READ
)
2566 return seq_lseek(file
, offset
, origin
);
2571 static const struct file_operations tracing_fops
= {
2572 .open
= tracing_open
,
2574 .write
= tracing_write_stub
,
2575 .llseek
= tracing_seek
,
2576 .release
= tracing_release
,
2579 static const struct file_operations show_traces_fops
= {
2580 .open
= show_traces_open
,
2582 .release
= seq_release
,
2583 .llseek
= seq_lseek
,
2587 * Only trace on a CPU if the bitmask is set:
2589 static cpumask_var_t tracing_cpumask
;
2592 * The tracer itself will not take this lock, but still we want
2593 * to provide a consistent cpumask to user-space:
2595 static DEFINE_MUTEX(tracing_cpumask_update_lock
);
2598 * Temporary storage for the character representation of the
2599 * CPU bitmask (and one more byte for the newline):
2601 static char mask_str
[NR_CPUS
+ 1];
2604 tracing_cpumask_read(struct file
*filp
, char __user
*ubuf
,
2605 size_t count
, loff_t
*ppos
)
2609 mutex_lock(&tracing_cpumask_update_lock
);
2611 len
= cpumask_scnprintf(mask_str
, count
, tracing_cpumask
);
2612 if (count
- len
< 2) {
2616 len
+= sprintf(mask_str
+ len
, "\n");
2617 count
= simple_read_from_buffer(ubuf
, count
, ppos
, mask_str
, NR_CPUS
+1);
2620 mutex_unlock(&tracing_cpumask_update_lock
);
2626 tracing_cpumask_write(struct file
*filp
, const char __user
*ubuf
,
2627 size_t count
, loff_t
*ppos
)
2630 cpumask_var_t tracing_cpumask_new
;
2632 if (!alloc_cpumask_var(&tracing_cpumask_new
, GFP_KERNEL
))
2635 err
= cpumask_parse_user(ubuf
, count
, tracing_cpumask_new
);
2639 mutex_lock(&tracing_cpumask_update_lock
);
2641 local_irq_disable();
2642 arch_spin_lock(&ftrace_max_lock
);
2643 for_each_tracing_cpu(cpu
) {
2645 * Increase/decrease the disabled counter if we are
2646 * about to flip a bit in the cpumask:
2648 if (cpumask_test_cpu(cpu
, tracing_cpumask
) &&
2649 !cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
2650 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
2652 if (!cpumask_test_cpu(cpu
, tracing_cpumask
) &&
2653 cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
2654 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
2657 arch_spin_unlock(&ftrace_max_lock
);
2660 cpumask_copy(tracing_cpumask
, tracing_cpumask_new
);
2662 mutex_unlock(&tracing_cpumask_update_lock
);
2663 free_cpumask_var(tracing_cpumask_new
);
2668 free_cpumask_var(tracing_cpumask_new
);
2673 static const struct file_operations tracing_cpumask_fops
= {
2674 .open
= tracing_open_generic
,
2675 .read
= tracing_cpumask_read
,
2676 .write
= tracing_cpumask_write
,
2677 .llseek
= generic_file_llseek
,
2680 static int tracing_trace_options_show(struct seq_file
*m
, void *v
)
2682 struct tracer_opt
*trace_opts
;
2686 mutex_lock(&trace_types_lock
);
2687 tracer_flags
= current_trace
->flags
->val
;
2688 trace_opts
= current_trace
->flags
->opts
;
2690 for (i
= 0; trace_options
[i
]; i
++) {
2691 if (trace_flags
& (1 << i
))
2692 seq_printf(m
, "%s\n", trace_options
[i
]);
2694 seq_printf(m
, "no%s\n", trace_options
[i
]);
2697 for (i
= 0; trace_opts
[i
].name
; i
++) {
2698 if (tracer_flags
& trace_opts
[i
].bit
)
2699 seq_printf(m
, "%s\n", trace_opts
[i
].name
);
2701 seq_printf(m
, "no%s\n", trace_opts
[i
].name
);
2703 mutex_unlock(&trace_types_lock
);
2708 static int __set_tracer_option(struct tracer
*trace
,
2709 struct tracer_flags
*tracer_flags
,
2710 struct tracer_opt
*opts
, int neg
)
2714 ret
= trace
->set_flag(tracer_flags
->val
, opts
->bit
, !neg
);
2719 tracer_flags
->val
&= ~opts
->bit
;
2721 tracer_flags
->val
|= opts
->bit
;
2725 /* Try to assign a tracer specific option */
2726 static int set_tracer_option(struct tracer
*trace
, char *cmp
, int neg
)
2728 struct tracer_flags
*tracer_flags
= trace
->flags
;
2729 struct tracer_opt
*opts
= NULL
;
2732 for (i
= 0; tracer_flags
->opts
[i
].name
; i
++) {
2733 opts
= &tracer_flags
->opts
[i
];
2735 if (strcmp(cmp
, opts
->name
) == 0)
2736 return __set_tracer_option(trace
, trace
->flags
,
2743 static void set_tracer_flags(unsigned int mask
, int enabled
)
2745 /* do nothing if flag is already set */
2746 if (!!(trace_flags
& mask
) == !!enabled
)
2750 trace_flags
|= mask
;
2752 trace_flags
&= ~mask
;
2754 if (mask
== TRACE_ITER_RECORD_CMD
)
2755 trace_event_enable_cmd_record(enabled
);
2757 if (mask
== TRACE_ITER_OVERWRITE
)
2758 ring_buffer_change_overwrite(global_trace
.buffer
, enabled
);
2762 tracing_trace_options_write(struct file
*filp
, const char __user
*ubuf
,
2763 size_t cnt
, loff_t
*ppos
)
2771 if (cnt
>= sizeof(buf
))
2774 if (copy_from_user(&buf
, ubuf
, cnt
))
2778 cmp
= strstrip(buf
);
2780 if (strncmp(cmp
, "no", 2) == 0) {
2785 for (i
= 0; trace_options
[i
]; i
++) {
2786 if (strcmp(cmp
, trace_options
[i
]) == 0) {
2787 set_tracer_flags(1 << i
, !neg
);
2792 /* If no option could be set, test the specific tracer options */
2793 if (!trace_options
[i
]) {
2794 mutex_lock(&trace_types_lock
);
2795 ret
= set_tracer_option(current_trace
, cmp
, neg
);
2796 mutex_unlock(&trace_types_lock
);
2806 static int tracing_trace_options_open(struct inode
*inode
, struct file
*file
)
2808 if (tracing_disabled
)
2810 return single_open(file
, tracing_trace_options_show
, NULL
);
2813 static const struct file_operations tracing_iter_fops
= {
2814 .open
= tracing_trace_options_open
,
2816 .llseek
= seq_lseek
,
2817 .release
= single_release
,
2818 .write
= tracing_trace_options_write
,
2821 static const char readme_msg
[] =
2822 "tracing mini-HOWTO:\n\n"
2823 "# mount -t debugfs nodev /sys/kernel/debug\n\n"
2824 "# cat /sys/kernel/debug/tracing/available_tracers\n"
2825 "wakeup wakeup_rt preemptirqsoff preemptoff irqsoff function nop\n\n"
2826 "# cat /sys/kernel/debug/tracing/current_tracer\n"
2828 "# echo wakeup > /sys/kernel/debug/tracing/current_tracer\n"
2829 "# cat /sys/kernel/debug/tracing/current_tracer\n"
2831 "# cat /sys/kernel/debug/tracing/trace_options\n"
2832 "noprint-parent nosym-offset nosym-addr noverbose\n"
2833 "# echo print-parent > /sys/kernel/debug/tracing/trace_options\n"
2834 "# echo 1 > /sys/kernel/debug/tracing/tracing_on\n"
2835 "# cat /sys/kernel/debug/tracing/trace > /tmp/trace.txt\n"
2836 "# echo 0 > /sys/kernel/debug/tracing/tracing_on\n"
2840 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
2841 size_t cnt
, loff_t
*ppos
)
2843 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
2844 readme_msg
, strlen(readme_msg
));
2847 static const struct file_operations tracing_readme_fops
= {
2848 .open
= tracing_open_generic
,
2849 .read
= tracing_readme_read
,
2850 .llseek
= generic_file_llseek
,
2854 tracing_saved_cmdlines_read(struct file
*file
, char __user
*ubuf
,
2855 size_t cnt
, loff_t
*ppos
)
2864 file_buf
= kmalloc(SAVED_CMDLINES
*(16+TASK_COMM_LEN
), GFP_KERNEL
);
2868 buf_comm
= kmalloc(TASK_COMM_LEN
, GFP_KERNEL
);
2876 for (i
= 0; i
< SAVED_CMDLINES
; i
++) {
2879 pid
= map_cmdline_to_pid
[i
];
2880 if (pid
== -1 || pid
== NO_CMDLINE_MAP
)
2883 trace_find_cmdline(pid
, buf_comm
);
2884 r
= sprintf(buf
, "%d %s\n", pid
, buf_comm
);
2889 len
= simple_read_from_buffer(ubuf
, cnt
, ppos
,
2898 static const struct file_operations tracing_saved_cmdlines_fops
= {
2899 .open
= tracing_open_generic
,
2900 .read
= tracing_saved_cmdlines_read
,
2901 .llseek
= generic_file_llseek
,
2905 tracing_ctrl_read(struct file
*filp
, char __user
*ubuf
,
2906 size_t cnt
, loff_t
*ppos
)
2911 r
= sprintf(buf
, "%u\n", tracer_enabled
);
2912 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2916 tracing_ctrl_write(struct file
*filp
, const char __user
*ubuf
,
2917 size_t cnt
, loff_t
*ppos
)
2919 struct trace_array
*tr
= filp
->private_data
;
2923 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
2929 mutex_lock(&trace_types_lock
);
2930 if (tracer_enabled
^ val
) {
2932 /* Only need to warn if this is used to change the state */
2933 WARN_ONCE(1, "tracing_enabled is deprecated. Use tracing_on");
2937 if (current_trace
->start
)
2938 current_trace
->start(tr
);
2943 if (current_trace
->stop
)
2944 current_trace
->stop(tr
);
2947 mutex_unlock(&trace_types_lock
);
2955 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
2956 size_t cnt
, loff_t
*ppos
)
2958 char buf
[MAX_TRACER_SIZE
+2];
2961 mutex_lock(&trace_types_lock
);
2963 r
= sprintf(buf
, "%s\n", current_trace
->name
);
2965 r
= sprintf(buf
, "\n");
2966 mutex_unlock(&trace_types_lock
);
2968 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2971 int tracer_init(struct tracer
*t
, struct trace_array
*tr
)
2973 tracing_reset_online_cpus(tr
);
2977 static int __tracing_resize_ring_buffer(unsigned long size
)
2982 * If kernel or user changes the size of the ring buffer
2983 * we use the size that was given, and we can forget about
2984 * expanding it later.
2986 ring_buffer_expanded
= 1;
2988 ret
= ring_buffer_resize(global_trace
.buffer
, size
);
2992 if (!current_trace
->use_max_tr
)
2995 ret
= ring_buffer_resize(max_tr
.buffer
, size
);
2999 r
= ring_buffer_resize(global_trace
.buffer
,
3000 global_trace
.entries
);
3003 * AARGH! We are left with different
3004 * size max buffer!!!!
3005 * The max buffer is our "snapshot" buffer.
3006 * When a tracer needs a snapshot (one of the
3007 * latency tracers), it swaps the max buffer
3008 * with the saved snap shot. We succeeded to
3009 * update the size of the main buffer, but failed to
3010 * update the size of the max buffer. But when we tried
3011 * to reset the main buffer to the original size, we
3012 * failed there too. This is very unlikely to
3013 * happen, but if it does, warn and kill all
3017 tracing_disabled
= 1;
3022 max_tr
.entries
= size
;
3024 global_trace
.entries
= size
;
3029 static ssize_t
tracing_resize_ring_buffer(unsigned long size
)
3031 int cpu
, ret
= size
;
3033 mutex_lock(&trace_types_lock
);
3037 /* disable all cpu buffers */
3038 for_each_tracing_cpu(cpu
) {
3039 if (global_trace
.data
[cpu
])
3040 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
3041 if (max_tr
.data
[cpu
])
3042 atomic_inc(&max_tr
.data
[cpu
]->disabled
);
3045 if (size
!= global_trace
.entries
)
3046 ret
= __tracing_resize_ring_buffer(size
);
3051 for_each_tracing_cpu(cpu
) {
3052 if (global_trace
.data
[cpu
])
3053 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
3054 if (max_tr
.data
[cpu
])
3055 atomic_dec(&max_tr
.data
[cpu
]->disabled
);
3059 mutex_unlock(&trace_types_lock
);
3066 * tracing_update_buffers - used by tracing facility to expand ring buffers
3068 * To save on memory when the tracing is never used on a system with it
3069 * configured in. The ring buffers are set to a minimum size. But once
3070 * a user starts to use the tracing facility, then they need to grow
3071 * to their default size.
3073 * This function is to be called when a tracer is about to be used.
3075 int tracing_update_buffers(void)
3079 mutex_lock(&trace_types_lock
);
3080 if (!ring_buffer_expanded
)
3081 ret
= __tracing_resize_ring_buffer(trace_buf_size
);
3082 mutex_unlock(&trace_types_lock
);
3087 struct trace_option_dentry
;
3089 static struct trace_option_dentry
*
3090 create_trace_option_files(struct tracer
*tracer
);
3093 destroy_trace_option_files(struct trace_option_dentry
*topts
);
3095 static int tracing_set_tracer(const char *buf
)
3097 static struct trace_option_dentry
*topts
;
3098 struct trace_array
*tr
= &global_trace
;
3102 mutex_lock(&trace_types_lock
);
3104 if (!ring_buffer_expanded
) {
3105 ret
= __tracing_resize_ring_buffer(trace_buf_size
);
3111 for (t
= trace_types
; t
; t
= t
->next
) {
3112 if (strcmp(t
->name
, buf
) == 0)
3119 if (t
== current_trace
)
3122 trace_branch_disable();
3123 if (current_trace
&& current_trace
->reset
)
3124 current_trace
->reset(tr
);
3125 if (current_trace
&& current_trace
->use_max_tr
) {
3127 * We don't free the ring buffer. instead, resize it because
3128 * The max_tr ring buffer has some state (e.g. ring->clock) and
3129 * we want preserve it.
3131 ring_buffer_resize(max_tr
.buffer
, 1);
3134 destroy_trace_option_files(topts
);
3138 topts
= create_trace_option_files(current_trace
);
3139 if (current_trace
->use_max_tr
) {
3140 ret
= ring_buffer_resize(max_tr
.buffer
, global_trace
.entries
);
3143 max_tr
.entries
= global_trace
.entries
;
3147 ret
= tracer_init(t
, tr
);
3152 trace_branch_enable(tr
);
3154 mutex_unlock(&trace_types_lock
);
3160 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
3161 size_t cnt
, loff_t
*ppos
)
3163 char buf
[MAX_TRACER_SIZE
+1];
3170 if (cnt
> MAX_TRACER_SIZE
)
3171 cnt
= MAX_TRACER_SIZE
;
3173 if (copy_from_user(&buf
, ubuf
, cnt
))
3178 /* strip ending whitespace. */
3179 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
3182 err
= tracing_set_tracer(buf
);
3192 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
3193 size_t cnt
, loff_t
*ppos
)
3195 unsigned long *ptr
= filp
->private_data
;
3199 r
= snprintf(buf
, sizeof(buf
), "%ld\n",
3200 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
3201 if (r
> sizeof(buf
))
3203 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3207 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
3208 size_t cnt
, loff_t
*ppos
)
3210 unsigned long *ptr
= filp
->private_data
;
3214 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
3223 static int tracing_open_pipe(struct inode
*inode
, struct file
*filp
)
3225 long cpu_file
= (long) inode
->i_private
;
3226 struct trace_iterator
*iter
;
3229 if (tracing_disabled
)
3232 mutex_lock(&trace_types_lock
);
3234 /* create a buffer to store the information to pass to userspace */
3235 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
3242 * We make a copy of the current tracer to avoid concurrent
3243 * changes on it while we are reading.
3245 iter
->trace
= kmalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
3251 *iter
->trace
= *current_trace
;
3253 if (!alloc_cpumask_var(&iter
->started
, GFP_KERNEL
)) {
3258 /* trace pipe does not show start of buffer */
3259 cpumask_setall(iter
->started
);
3261 if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
3262 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
3264 iter
->cpu_file
= cpu_file
;
3265 iter
->tr
= &global_trace
;
3266 mutex_init(&iter
->mutex
);
3267 filp
->private_data
= iter
;
3269 if (iter
->trace
->pipe_open
)
3270 iter
->trace
->pipe_open(iter
);
3272 nonseekable_open(inode
, filp
);
3274 mutex_unlock(&trace_types_lock
);
3280 mutex_unlock(&trace_types_lock
);
3284 static int tracing_release_pipe(struct inode
*inode
, struct file
*file
)
3286 struct trace_iterator
*iter
= file
->private_data
;
3288 mutex_lock(&trace_types_lock
);
3290 if (iter
->trace
->pipe_close
)
3291 iter
->trace
->pipe_close(iter
);
3293 mutex_unlock(&trace_types_lock
);
3295 free_cpumask_var(iter
->started
);
3296 mutex_destroy(&iter
->mutex
);
3304 tracing_poll_pipe(struct file
*filp
, poll_table
*poll_table
)
3306 struct trace_iterator
*iter
= filp
->private_data
;
3308 if (trace_flags
& TRACE_ITER_BLOCK
) {
3310 * Always select as readable when in blocking mode
3312 return POLLIN
| POLLRDNORM
;
3314 if (!trace_empty(iter
))
3315 return POLLIN
| POLLRDNORM
;
3316 poll_wait(filp
, &trace_wait
, poll_table
);
3317 if (!trace_empty(iter
))
3318 return POLLIN
| POLLRDNORM
;
3325 void default_wait_pipe(struct trace_iterator
*iter
)
3329 prepare_to_wait(&trace_wait
, &wait
, TASK_INTERRUPTIBLE
);
3331 if (trace_empty(iter
))
3334 finish_wait(&trace_wait
, &wait
);
3338 * This is a make-shift waitqueue.
3339 * A tracer might use this callback on some rare cases:
3341 * 1) the current tracer might hold the runqueue lock when it wakes up
3342 * a reader, hence a deadlock (sched, function, and function graph tracers)
3343 * 2) the function tracers, trace all functions, we don't want
3344 * the overhead of calling wake_up and friends
3345 * (and tracing them too)
3347 * Anyway, this is really very primitive wakeup.
3349 void poll_wait_pipe(struct trace_iterator
*iter
)
3351 set_current_state(TASK_INTERRUPTIBLE
);
3352 /* sleep for 100 msecs, and try again. */
3353 schedule_timeout(HZ
/ 10);
3356 /* Must be called with trace_types_lock mutex held. */
3357 static int tracing_wait_pipe(struct file
*filp
)
3359 struct trace_iterator
*iter
= filp
->private_data
;
3361 while (trace_empty(iter
)) {
3363 if ((filp
->f_flags
& O_NONBLOCK
)) {
3367 mutex_unlock(&iter
->mutex
);
3369 iter
->trace
->wait_pipe(iter
);
3371 mutex_lock(&iter
->mutex
);
3373 if (signal_pending(current
))
3377 * We block until we read something and tracing is disabled.
3378 * We still block if tracing is disabled, but we have never
3379 * read anything. This allows a user to cat this file, and
3380 * then enable tracing. But after we have read something,
3381 * we give an EOF when tracing is again disabled.
3383 * iter->pos will be 0 if we haven't read anything.
3385 if (!tracer_enabled
&& iter
->pos
)
3396 tracing_read_pipe(struct file
*filp
, char __user
*ubuf
,
3397 size_t cnt
, loff_t
*ppos
)
3399 struct trace_iterator
*iter
= filp
->private_data
;
3400 static struct tracer
*old_tracer
;
3403 /* return any leftover data */
3404 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
3408 trace_seq_init(&iter
->seq
);
3410 /* copy the tracer to avoid using a global lock all around */
3411 mutex_lock(&trace_types_lock
);
3412 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
3413 old_tracer
= current_trace
;
3414 *iter
->trace
= *current_trace
;
3416 mutex_unlock(&trace_types_lock
);
3419 * Avoid more than one consumer on a single file descriptor
3420 * This is just a matter of traces coherency, the ring buffer itself
3423 mutex_lock(&iter
->mutex
);
3424 if (iter
->trace
->read
) {
3425 sret
= iter
->trace
->read(iter
, filp
, ubuf
, cnt
, ppos
);
3431 sret
= tracing_wait_pipe(filp
);
3435 /* stop when tracing is finished */
3436 if (trace_empty(iter
)) {
3441 if (cnt
>= PAGE_SIZE
)
3442 cnt
= PAGE_SIZE
- 1;
3444 /* reset all but tr, trace, and overruns */
3445 memset(&iter
->seq
, 0,
3446 sizeof(struct trace_iterator
) -
3447 offsetof(struct trace_iterator
, seq
));
3450 trace_event_read_lock();
3451 trace_access_lock(iter
->cpu_file
);
3452 while (trace_find_next_entry_inc(iter
) != NULL
) {
3453 enum print_line_t ret
;
3454 int len
= iter
->seq
.len
;
3456 ret
= print_trace_line(iter
);
3457 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
3458 /* don't print partial lines */
3459 iter
->seq
.len
= len
;
3462 if (ret
!= TRACE_TYPE_NO_CONSUME
)
3463 trace_consume(iter
);
3465 if (iter
->seq
.len
>= cnt
)
3469 * Setting the full flag means we reached the trace_seq buffer
3470 * size and we should leave by partial output condition above.
3471 * One of the trace_seq_* functions is not used properly.
3473 WARN_ONCE(iter
->seq
.full
, "full flag set for trace type %d",
3476 trace_access_unlock(iter
->cpu_file
);
3477 trace_event_read_unlock();
3479 /* Now copy what we have to the user */
3480 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
3481 if (iter
->seq
.readpos
>= iter
->seq
.len
)
3482 trace_seq_init(&iter
->seq
);
3485 * If there was nothing to send to user, in spite of consuming trace
3486 * entries, go back to wait for more entries.
3492 mutex_unlock(&iter
->mutex
);
3497 static void tracing_pipe_buf_release(struct pipe_inode_info
*pipe
,
3498 struct pipe_buffer
*buf
)
3500 __free_page(buf
->page
);
3503 static void tracing_spd_release_pipe(struct splice_pipe_desc
*spd
,
3506 __free_page(spd
->pages
[idx
]);
3509 static const struct pipe_buf_operations tracing_pipe_buf_ops
= {
3511 .map
= generic_pipe_buf_map
,
3512 .unmap
= generic_pipe_buf_unmap
,
3513 .confirm
= generic_pipe_buf_confirm
,
3514 .release
= tracing_pipe_buf_release
,
3515 .steal
= generic_pipe_buf_steal
,
3516 .get
= generic_pipe_buf_get
,
3520 tracing_fill_pipe_page(size_t rem
, struct trace_iterator
*iter
)
3525 /* Seq buffer is page-sized, exactly what we need. */
3527 count
= iter
->seq
.len
;
3528 ret
= print_trace_line(iter
);
3529 count
= iter
->seq
.len
- count
;
3532 iter
->seq
.len
-= count
;
3535 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
3536 iter
->seq
.len
-= count
;
3540 if (ret
!= TRACE_TYPE_NO_CONSUME
)
3541 trace_consume(iter
);
3543 if (!trace_find_next_entry_inc(iter
)) {
3553 static ssize_t
tracing_splice_read_pipe(struct file
*filp
,
3555 struct pipe_inode_info
*pipe
,
3559 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
3560 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
3561 struct trace_iterator
*iter
= filp
->private_data
;
3562 struct splice_pipe_desc spd
= {
3564 .partial
= partial_def
,
3565 .nr_pages
= 0, /* This gets updated below. */
3567 .ops
= &tracing_pipe_buf_ops
,
3568 .spd_release
= tracing_spd_release_pipe
,
3570 static struct tracer
*old_tracer
;
3575 if (splice_grow_spd(pipe
, &spd
))
3578 /* copy the tracer to avoid using a global lock all around */
3579 mutex_lock(&trace_types_lock
);
3580 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
3581 old_tracer
= current_trace
;
3582 *iter
->trace
= *current_trace
;
3584 mutex_unlock(&trace_types_lock
);
3586 mutex_lock(&iter
->mutex
);
3588 if (iter
->trace
->splice_read
) {
3589 ret
= iter
->trace
->splice_read(iter
, filp
,
3590 ppos
, pipe
, len
, flags
);
3595 ret
= tracing_wait_pipe(filp
);
3599 if (!iter
->ent
&& !trace_find_next_entry_inc(iter
)) {
3604 trace_event_read_lock();
3605 trace_access_lock(iter
->cpu_file
);
3607 /* Fill as many pages as possible. */
3608 for (i
= 0, rem
= len
; i
< pipe
->buffers
&& rem
; i
++) {
3609 spd
.pages
[i
] = alloc_page(GFP_KERNEL
);
3613 rem
= tracing_fill_pipe_page(rem
, iter
);
3615 /* Copy the data into the page, so we can start over. */
3616 ret
= trace_seq_to_buffer(&iter
->seq
,
3617 page_address(spd
.pages
[i
]),
3620 __free_page(spd
.pages
[i
]);
3623 spd
.partial
[i
].offset
= 0;
3624 spd
.partial
[i
].len
= iter
->seq
.len
;
3626 trace_seq_init(&iter
->seq
);
3629 trace_access_unlock(iter
->cpu_file
);
3630 trace_event_read_unlock();
3631 mutex_unlock(&iter
->mutex
);
3635 ret
= splice_to_pipe(pipe
, &spd
);
3637 splice_shrink_spd(pipe
, &spd
);
3641 mutex_unlock(&iter
->mutex
);
3646 tracing_entries_read(struct file
*filp
, char __user
*ubuf
,
3647 size_t cnt
, loff_t
*ppos
)
3649 struct trace_array
*tr
= filp
->private_data
;
3653 mutex_lock(&trace_types_lock
);
3654 if (!ring_buffer_expanded
)
3655 r
= sprintf(buf
, "%lu (expanded: %lu)\n",
3657 trace_buf_size
>> 10);
3659 r
= sprintf(buf
, "%lu\n", tr
->entries
>> 10);
3660 mutex_unlock(&trace_types_lock
);
3662 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3666 tracing_entries_write(struct file
*filp
, const char __user
*ubuf
,
3667 size_t cnt
, loff_t
*ppos
)
3672 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
3676 /* must have at least 1 entry */
3680 /* value is in KB */
3683 ret
= tracing_resize_ring_buffer(val
);
3693 tracing_total_entries_read(struct file
*filp
, char __user
*ubuf
,
3694 size_t cnt
, loff_t
*ppos
)
3696 struct trace_array
*tr
= filp
->private_data
;
3699 unsigned long size
= 0, expanded_size
= 0;
3701 mutex_lock(&trace_types_lock
);
3702 for_each_tracing_cpu(cpu
) {
3703 size
+= tr
->entries
>> 10;
3704 if (!ring_buffer_expanded
)
3705 expanded_size
+= trace_buf_size
>> 10;
3707 if (ring_buffer_expanded
)
3708 r
= sprintf(buf
, "%lu\n", size
);
3710 r
= sprintf(buf
, "%lu (expanded: %lu)\n", size
, expanded_size
);
3711 mutex_unlock(&trace_types_lock
);
3713 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3717 tracing_free_buffer_write(struct file
*filp
, const char __user
*ubuf
,
3718 size_t cnt
, loff_t
*ppos
)
3721 * There is no need to read what the user has written, this function
3722 * is just to make sure that there is no error when "echo" is used
3731 tracing_free_buffer_release(struct inode
*inode
, struct file
*filp
)
3733 /* disable tracing ? */
3734 if (trace_flags
& TRACE_ITER_STOP_ON_FREE
)
3736 /* resize the ring buffer to 0 */
3737 tracing_resize_ring_buffer(0);
3743 tracing_mark_write(struct file
*filp
, const char __user
*ubuf
,
3744 size_t cnt
, loff_t
*fpos
)
3746 unsigned long addr
= (unsigned long)ubuf
;
3747 struct ring_buffer_event
*event
;
3748 struct ring_buffer
*buffer
;
3749 struct print_entry
*entry
;
3750 unsigned long irq_flags
;
3751 struct page
*pages
[2];
3761 if (tracing_disabled
)
3764 if (cnt
> TRACE_BUF_SIZE
)
3765 cnt
= TRACE_BUF_SIZE
;
3768 * Userspace is injecting traces into the kernel trace buffer.
3769 * We want to be as non intrusive as possible.
3770 * To do so, we do not want to allocate any special buffers
3771 * or take any locks, but instead write the userspace data
3772 * straight into the ring buffer.
3774 * First we need to pin the userspace buffer into memory,
3775 * which, most likely it is, because it just referenced it.
3776 * But there's no guarantee that it is. By using get_user_pages_fast()
3777 * and kmap_atomic/kunmap_atomic() we can get access to the
3778 * pages directly. We then write the data directly into the
3781 BUILD_BUG_ON(TRACE_BUF_SIZE
>= PAGE_SIZE
);
3783 /* check if we cross pages */
3784 if ((addr
& PAGE_MASK
) != ((addr
+ cnt
) & PAGE_MASK
))
3787 offset
= addr
& (PAGE_SIZE
- 1);
3790 ret
= get_user_pages_fast(addr
, nr_pages
, 0, pages
);
3791 if (ret
< nr_pages
) {
3793 put_page(pages
[ret
]);
3798 page1
= kmap_atomic(pages
[0]);
3800 page2
= kmap_atomic(pages
[1]);
3802 local_save_flags(irq_flags
);
3803 size
= sizeof(*entry
) + cnt
+ 2; /* possible \n added */
3804 buffer
= global_trace
.buffer
;
3805 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, size
,
3806 irq_flags
, preempt_count());
3808 /* Ring buffer disabled, return as if not open for write */
3813 entry
= ring_buffer_event_data(event
);
3814 entry
->ip
= _THIS_IP_
;
3816 if (nr_pages
== 2) {
3817 len
= PAGE_SIZE
- offset
;
3818 memcpy(&entry
->buf
, page1
+ offset
, len
);
3819 memcpy(&entry
->buf
[len
], page2
, cnt
- len
);
3821 memcpy(&entry
->buf
, page1
+ offset
, cnt
);
3823 if (entry
->buf
[cnt
- 1] != '\n') {
3824 entry
->buf
[cnt
] = '\n';
3825 entry
->buf
[cnt
+ 1] = '\0';
3827 entry
->buf
[cnt
] = '\0';
3829 ring_buffer_unlock_commit(buffer
, event
);
3837 kunmap_atomic(page2
);
3838 kunmap_atomic(page1
);
3839 while (nr_pages
> 0)
3840 put_page(pages
[--nr_pages
]);
3845 static int tracing_clock_show(struct seq_file
*m
, void *v
)
3849 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++)
3851 "%s%s%s%s", i
? " " : "",
3852 i
== trace_clock_id
? "[" : "", trace_clocks
[i
].name
,
3853 i
== trace_clock_id
? "]" : "");
3859 static ssize_t
tracing_clock_write(struct file
*filp
, const char __user
*ubuf
,
3860 size_t cnt
, loff_t
*fpos
)
3863 const char *clockstr
;
3866 if (cnt
>= sizeof(buf
))
3869 if (copy_from_user(&buf
, ubuf
, cnt
))
3874 clockstr
= strstrip(buf
);
3876 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++) {
3877 if (strcmp(trace_clocks
[i
].name
, clockstr
) == 0)
3880 if (i
== ARRAY_SIZE(trace_clocks
))
3885 mutex_lock(&trace_types_lock
);
3887 ring_buffer_set_clock(global_trace
.buffer
, trace_clocks
[i
].func
);
3889 ring_buffer_set_clock(max_tr
.buffer
, trace_clocks
[i
].func
);
3891 mutex_unlock(&trace_types_lock
);
3898 static int tracing_clock_open(struct inode
*inode
, struct file
*file
)
3900 if (tracing_disabled
)
3902 return single_open(file
, tracing_clock_show
, NULL
);
3905 static const struct file_operations tracing_max_lat_fops
= {
3906 .open
= tracing_open_generic
,
3907 .read
= tracing_max_lat_read
,
3908 .write
= tracing_max_lat_write
,
3909 .llseek
= generic_file_llseek
,
3912 static const struct file_operations tracing_ctrl_fops
= {
3913 .open
= tracing_open_generic
,
3914 .read
= tracing_ctrl_read
,
3915 .write
= tracing_ctrl_write
,
3916 .llseek
= generic_file_llseek
,
3919 static const struct file_operations set_tracer_fops
= {
3920 .open
= tracing_open_generic
,
3921 .read
= tracing_set_trace_read
,
3922 .write
= tracing_set_trace_write
,
3923 .llseek
= generic_file_llseek
,
3926 static const struct file_operations tracing_pipe_fops
= {
3927 .open
= tracing_open_pipe
,
3928 .poll
= tracing_poll_pipe
,
3929 .read
= tracing_read_pipe
,
3930 .splice_read
= tracing_splice_read_pipe
,
3931 .release
= tracing_release_pipe
,
3932 .llseek
= no_llseek
,
3935 static const struct file_operations tracing_entries_fops
= {
3936 .open
= tracing_open_generic
,
3937 .read
= tracing_entries_read
,
3938 .write
= tracing_entries_write
,
3939 .llseek
= generic_file_llseek
,
3942 static const struct file_operations tracing_total_entries_fops
= {
3943 .open
= tracing_open_generic
,
3944 .read
= tracing_total_entries_read
,
3945 .llseek
= generic_file_llseek
,
3948 static const struct file_operations tracing_free_buffer_fops
= {
3949 .write
= tracing_free_buffer_write
,
3950 .release
= tracing_free_buffer_release
,
3953 static const struct file_operations tracing_mark_fops
= {
3954 .open
= tracing_open_generic
,
3955 .write
= tracing_mark_write
,
3956 .llseek
= generic_file_llseek
,
3959 static const struct file_operations trace_clock_fops
= {
3960 .open
= tracing_clock_open
,
3962 .llseek
= seq_lseek
,
3963 .release
= single_release
,
3964 .write
= tracing_clock_write
,
3967 struct ftrace_buffer_info
{
3968 struct trace_array
*tr
;
3974 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
)
3976 int cpu
= (int)(long)inode
->i_private
;
3977 struct ftrace_buffer_info
*info
;
3979 if (tracing_disabled
)
3982 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
3986 info
->tr
= &global_trace
;
3989 /* Force reading ring buffer for first read */
3990 info
->read
= (unsigned int)-1;
3992 filp
->private_data
= info
;
3994 return nonseekable_open(inode
, filp
);
3998 tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
3999 size_t count
, loff_t
*ppos
)
4001 struct ftrace_buffer_info
*info
= filp
->private_data
;
4009 info
->spare
= ring_buffer_alloc_read_page(info
->tr
->buffer
, info
->cpu
);
4013 /* Do we have previous read data to read? */
4014 if (info
->read
< PAGE_SIZE
)
4017 trace_access_lock(info
->cpu
);
4018 ret
= ring_buffer_read_page(info
->tr
->buffer
,
4022 trace_access_unlock(info
->cpu
);
4029 size
= PAGE_SIZE
- info
->read
;
4033 ret
= copy_to_user(ubuf
, info
->spare
+ info
->read
, size
);
4044 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
)
4046 struct ftrace_buffer_info
*info
= file
->private_data
;
4049 ring_buffer_free_read_page(info
->tr
->buffer
, info
->spare
);
4056 struct ring_buffer
*buffer
;
4061 static void buffer_pipe_buf_release(struct pipe_inode_info
*pipe
,
4062 struct pipe_buffer
*buf
)
4064 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
4069 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
4074 static int buffer_pipe_buf_steal(struct pipe_inode_info
*pipe
,
4075 struct pipe_buffer
*buf
)
4080 static void buffer_pipe_buf_get(struct pipe_inode_info
*pipe
,
4081 struct pipe_buffer
*buf
)
4083 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
4088 /* Pipe buffer operations for a buffer. */
4089 static const struct pipe_buf_operations buffer_pipe_buf_ops
= {
4091 .map
= generic_pipe_buf_map
,
4092 .unmap
= generic_pipe_buf_unmap
,
4093 .confirm
= generic_pipe_buf_confirm
,
4094 .release
= buffer_pipe_buf_release
,
4095 .steal
= buffer_pipe_buf_steal
,
4096 .get
= buffer_pipe_buf_get
,
4100 * Callback from splice_to_pipe(), if we need to release some pages
4101 * at the end of the spd in case we error'ed out in filling the pipe.
4103 static void buffer_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
4105 struct buffer_ref
*ref
=
4106 (struct buffer_ref
*)spd
->partial
[i
].private;
4111 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
4113 spd
->partial
[i
].private = 0;
4117 tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
4118 struct pipe_inode_info
*pipe
, size_t len
,
4121 struct ftrace_buffer_info
*info
= file
->private_data
;
4122 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
4123 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
4124 struct splice_pipe_desc spd
= {
4126 .partial
= partial_def
,
4128 .ops
= &buffer_pipe_buf_ops
,
4129 .spd_release
= buffer_spd_release
,
4131 struct buffer_ref
*ref
;
4132 int entries
, size
, i
;
4135 if (splice_grow_spd(pipe
, &spd
))
4138 if (*ppos
& (PAGE_SIZE
- 1)) {
4139 WARN_ONCE(1, "Ftrace: previous read must page-align\n");
4144 if (len
& (PAGE_SIZE
- 1)) {
4145 WARN_ONCE(1, "Ftrace: splice_read should page-align\n");
4146 if (len
< PAGE_SIZE
) {
4153 trace_access_lock(info
->cpu
);
4154 entries
= ring_buffer_entries_cpu(info
->tr
->buffer
, info
->cpu
);
4156 for (i
= 0; i
< pipe
->buffers
&& len
&& entries
; i
++, len
-= PAGE_SIZE
) {
4160 ref
= kzalloc(sizeof(*ref
), GFP_KERNEL
);
4165 ref
->buffer
= info
->tr
->buffer
;
4166 ref
->page
= ring_buffer_alloc_read_page(ref
->buffer
, info
->cpu
);
4172 r
= ring_buffer_read_page(ref
->buffer
, &ref
->page
,
4175 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
4181 * zero out any left over data, this is going to
4184 size
= ring_buffer_page_len(ref
->page
);
4185 if (size
< PAGE_SIZE
)
4186 memset(ref
->page
+ size
, 0, PAGE_SIZE
- size
);
4188 page
= virt_to_page(ref
->page
);
4190 spd
.pages
[i
] = page
;
4191 spd
.partial
[i
].len
= PAGE_SIZE
;
4192 spd
.partial
[i
].offset
= 0;
4193 spd
.partial
[i
].private = (unsigned long)ref
;
4197 entries
= ring_buffer_entries_cpu(info
->tr
->buffer
, info
->cpu
);
4200 trace_access_unlock(info
->cpu
);
4203 /* did we read anything? */
4204 if (!spd
.nr_pages
) {
4205 if (flags
& SPLICE_F_NONBLOCK
)
4213 ret
= splice_to_pipe(pipe
, &spd
);
4214 splice_shrink_spd(pipe
, &spd
);
4219 static const struct file_operations tracing_buffers_fops
= {
4220 .open
= tracing_buffers_open
,
4221 .read
= tracing_buffers_read
,
4222 .release
= tracing_buffers_release
,
4223 .splice_read
= tracing_buffers_splice_read
,
4224 .llseek
= no_llseek
,
4228 tracing_stats_read(struct file
*filp
, char __user
*ubuf
,
4229 size_t count
, loff_t
*ppos
)
4231 unsigned long cpu
= (unsigned long)filp
->private_data
;
4232 struct trace_array
*tr
= &global_trace
;
4233 struct trace_seq
*s
;
4235 unsigned long long t
;
4236 unsigned long usec_rem
;
4238 s
= kmalloc(sizeof(*s
), GFP_KERNEL
);
4244 cnt
= ring_buffer_entries_cpu(tr
->buffer
, cpu
);
4245 trace_seq_printf(s
, "entries: %ld\n", cnt
);
4247 cnt
= ring_buffer_overrun_cpu(tr
->buffer
, cpu
);
4248 trace_seq_printf(s
, "overrun: %ld\n", cnt
);
4250 cnt
= ring_buffer_commit_overrun_cpu(tr
->buffer
, cpu
);
4251 trace_seq_printf(s
, "commit overrun: %ld\n", cnt
);
4253 cnt
= ring_buffer_bytes_cpu(tr
->buffer
, cpu
);
4254 trace_seq_printf(s
, "bytes: %ld\n", cnt
);
4256 t
= ns2usecs(ring_buffer_oldest_event_ts(tr
->buffer
, cpu
));
4257 usec_rem
= do_div(t
, USEC_PER_SEC
);
4258 trace_seq_printf(s
, "oldest event ts: %5llu.%06lu\n", t
, usec_rem
);
4260 t
= ns2usecs(ring_buffer_time_stamp(tr
->buffer
, cpu
));
4261 usec_rem
= do_div(t
, USEC_PER_SEC
);
4262 trace_seq_printf(s
, "now ts: %5llu.%06lu\n", t
, usec_rem
);
4264 count
= simple_read_from_buffer(ubuf
, count
, ppos
, s
->buffer
, s
->len
);
4271 static const struct file_operations tracing_stats_fops
= {
4272 .open
= tracing_open_generic
,
4273 .read
= tracing_stats_read
,
4274 .llseek
= generic_file_llseek
,
4277 #ifdef CONFIG_DYNAMIC_FTRACE
4279 int __weak
ftrace_arch_read_dyn_info(char *buf
, int size
)
4285 tracing_read_dyn_info(struct file
*filp
, char __user
*ubuf
,
4286 size_t cnt
, loff_t
*ppos
)
4288 static char ftrace_dyn_info_buffer
[1024];
4289 static DEFINE_MUTEX(dyn_info_mutex
);
4290 unsigned long *p
= filp
->private_data
;
4291 char *buf
= ftrace_dyn_info_buffer
;
4292 int size
= ARRAY_SIZE(ftrace_dyn_info_buffer
);
4295 mutex_lock(&dyn_info_mutex
);
4296 r
= sprintf(buf
, "%ld ", *p
);
4298 r
+= ftrace_arch_read_dyn_info(buf
+r
, (size
-1)-r
);
4301 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
4303 mutex_unlock(&dyn_info_mutex
);
4308 static const struct file_operations tracing_dyn_info_fops
= {
4309 .open
= tracing_open_generic
,
4310 .read
= tracing_read_dyn_info
,
4311 .llseek
= generic_file_llseek
,
4315 static struct dentry
*d_tracer
;
4317 struct dentry
*tracing_init_dentry(void)
4324 if (!debugfs_initialized())
4327 d_tracer
= debugfs_create_dir("tracing", NULL
);
4329 if (!d_tracer
&& !once
) {
4331 pr_warning("Could not create debugfs directory 'tracing'\n");
4338 static struct dentry
*d_percpu
;
4340 struct dentry
*tracing_dentry_percpu(void)
4343 struct dentry
*d_tracer
;
4348 d_tracer
= tracing_init_dentry();
4353 d_percpu
= debugfs_create_dir("per_cpu", d_tracer
);
4355 if (!d_percpu
&& !once
) {
4357 pr_warning("Could not create debugfs directory 'per_cpu'\n");
4364 static void tracing_init_debugfs_percpu(long cpu
)
4366 struct dentry
*d_percpu
= tracing_dentry_percpu();
4367 struct dentry
*d_cpu
;
4368 char cpu_dir
[30]; /* 30 characters should be more than enough */
4370 snprintf(cpu_dir
, 30, "cpu%ld", cpu
);
4371 d_cpu
= debugfs_create_dir(cpu_dir
, d_percpu
);
4373 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir
);
4377 /* per cpu trace_pipe */
4378 trace_create_file("trace_pipe", 0444, d_cpu
,
4379 (void *) cpu
, &tracing_pipe_fops
);
4382 trace_create_file("trace", 0644, d_cpu
,
4383 (void *) cpu
, &tracing_fops
);
4385 trace_create_file("trace_pipe_raw", 0444, d_cpu
,
4386 (void *) cpu
, &tracing_buffers_fops
);
4388 trace_create_file("stats", 0444, d_cpu
,
4389 (void *) cpu
, &tracing_stats_fops
);
4392 #ifdef CONFIG_FTRACE_SELFTEST
4393 /* Let selftest have access to static functions in this file */
4394 #include "trace_selftest.c"
4397 struct trace_option_dentry
{
4398 struct tracer_opt
*opt
;
4399 struct tracer_flags
*flags
;
4400 struct dentry
*entry
;
4404 trace_options_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
4407 struct trace_option_dentry
*topt
= filp
->private_data
;
4410 if (topt
->flags
->val
& topt
->opt
->bit
)
4415 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
4419 trace_options_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
4422 struct trace_option_dentry
*topt
= filp
->private_data
;
4426 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
4430 if (val
!= 0 && val
!= 1)
4433 if (!!(topt
->flags
->val
& topt
->opt
->bit
) != val
) {
4434 mutex_lock(&trace_types_lock
);
4435 ret
= __set_tracer_option(current_trace
, topt
->flags
,
4437 mutex_unlock(&trace_types_lock
);
4448 static const struct file_operations trace_options_fops
= {
4449 .open
= tracing_open_generic
,
4450 .read
= trace_options_read
,
4451 .write
= trace_options_write
,
4452 .llseek
= generic_file_llseek
,
4456 trace_options_core_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
4459 long index
= (long)filp
->private_data
;
4462 if (trace_flags
& (1 << index
))
4467 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
4471 trace_options_core_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
4474 long index
= (long)filp
->private_data
;
4478 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
4482 if (val
!= 0 && val
!= 1)
4484 set_tracer_flags(1 << index
, val
);
4491 static const struct file_operations trace_options_core_fops
= {
4492 .open
= tracing_open_generic
,
4493 .read
= trace_options_core_read
,
4494 .write
= trace_options_core_write
,
4495 .llseek
= generic_file_llseek
,
4498 struct dentry
*trace_create_file(const char *name
,
4500 struct dentry
*parent
,
4502 const struct file_operations
*fops
)
4506 ret
= debugfs_create_file(name
, mode
, parent
, data
, fops
);
4508 pr_warning("Could not create debugfs '%s' entry\n", name
);
4514 static struct dentry
*trace_options_init_dentry(void)
4516 struct dentry
*d_tracer
;
4517 static struct dentry
*t_options
;
4522 d_tracer
= tracing_init_dentry();
4526 t_options
= debugfs_create_dir("options", d_tracer
);
4528 pr_warning("Could not create debugfs directory 'options'\n");
4536 create_trace_option_file(struct trace_option_dentry
*topt
,
4537 struct tracer_flags
*flags
,
4538 struct tracer_opt
*opt
)
4540 struct dentry
*t_options
;
4542 t_options
= trace_options_init_dentry();
4546 topt
->flags
= flags
;
4549 topt
->entry
= trace_create_file(opt
->name
, 0644, t_options
, topt
,
4550 &trace_options_fops
);
4554 static struct trace_option_dentry
*
4555 create_trace_option_files(struct tracer
*tracer
)
4557 struct trace_option_dentry
*topts
;
4558 struct tracer_flags
*flags
;
4559 struct tracer_opt
*opts
;
4565 flags
= tracer
->flags
;
4567 if (!flags
|| !flags
->opts
)
4572 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
4575 topts
= kcalloc(cnt
+ 1, sizeof(*topts
), GFP_KERNEL
);
4579 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
4580 create_trace_option_file(&topts
[cnt
], flags
,
4587 destroy_trace_option_files(struct trace_option_dentry
*topts
)
4594 for (cnt
= 0; topts
[cnt
].opt
; cnt
++) {
4595 if (topts
[cnt
].entry
)
4596 debugfs_remove(topts
[cnt
].entry
);
4602 static struct dentry
*
4603 create_trace_option_core_file(const char *option
, long index
)
4605 struct dentry
*t_options
;
4607 t_options
= trace_options_init_dentry();
4611 return trace_create_file(option
, 0644, t_options
, (void *)index
,
4612 &trace_options_core_fops
);
4615 static __init
void create_trace_options_dir(void)
4617 struct dentry
*t_options
;
4620 t_options
= trace_options_init_dentry();
4624 for (i
= 0; trace_options
[i
]; i
++)
4625 create_trace_option_core_file(trace_options
[i
], i
);
4629 rb_simple_read(struct file
*filp
, char __user
*ubuf
,
4630 size_t cnt
, loff_t
*ppos
)
4632 struct trace_array
*tr
= filp
->private_data
;
4633 struct ring_buffer
*buffer
= tr
->buffer
;
4638 r
= ring_buffer_record_is_on(buffer
);
4642 r
= sprintf(buf
, "%d\n", r
);
4644 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
4648 rb_simple_write(struct file
*filp
, const char __user
*ubuf
,
4649 size_t cnt
, loff_t
*ppos
)
4651 struct trace_array
*tr
= filp
->private_data
;
4652 struct ring_buffer
*buffer
= tr
->buffer
;
4656 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
4662 ring_buffer_record_on(buffer
);
4664 ring_buffer_record_off(buffer
);
4672 static const struct file_operations rb_simple_fops
= {
4673 .open
= tracing_open_generic
,
4674 .read
= rb_simple_read
,
4675 .write
= rb_simple_write
,
4676 .llseek
= default_llseek
,
4679 static __init
int tracer_init_debugfs(void)
4681 struct dentry
*d_tracer
;
4684 trace_access_lock_init();
4686 d_tracer
= tracing_init_dentry();
4688 trace_create_file("tracing_enabled", 0644, d_tracer
,
4689 &global_trace
, &tracing_ctrl_fops
);
4691 trace_create_file("trace_options", 0644, d_tracer
,
4692 NULL
, &tracing_iter_fops
);
4694 trace_create_file("tracing_cpumask", 0644, d_tracer
,
4695 NULL
, &tracing_cpumask_fops
);
4697 trace_create_file("trace", 0644, d_tracer
,
4698 (void *) TRACE_PIPE_ALL_CPU
, &tracing_fops
);
4700 trace_create_file("available_tracers", 0444, d_tracer
,
4701 &global_trace
, &show_traces_fops
);
4703 trace_create_file("current_tracer", 0644, d_tracer
,
4704 &global_trace
, &set_tracer_fops
);
4706 #ifdef CONFIG_TRACER_MAX_TRACE
4707 trace_create_file("tracing_max_latency", 0644, d_tracer
,
4708 &tracing_max_latency
, &tracing_max_lat_fops
);
4711 trace_create_file("tracing_thresh", 0644, d_tracer
,
4712 &tracing_thresh
, &tracing_max_lat_fops
);
4714 trace_create_file("README", 0444, d_tracer
,
4715 NULL
, &tracing_readme_fops
);
4717 trace_create_file("trace_pipe", 0444, d_tracer
,
4718 (void *) TRACE_PIPE_ALL_CPU
, &tracing_pipe_fops
);
4720 trace_create_file("buffer_size_kb", 0644, d_tracer
,
4721 &global_trace
, &tracing_entries_fops
);
4723 trace_create_file("buffer_total_size_kb", 0444, d_tracer
,
4724 &global_trace
, &tracing_total_entries_fops
);
4726 trace_create_file("free_buffer", 0644, d_tracer
,
4727 &global_trace
, &tracing_free_buffer_fops
);
4729 trace_create_file("trace_marker", 0220, d_tracer
,
4730 NULL
, &tracing_mark_fops
);
4732 trace_create_file("saved_cmdlines", 0444, d_tracer
,
4733 NULL
, &tracing_saved_cmdlines_fops
);
4735 trace_create_file("trace_clock", 0644, d_tracer
, NULL
,
4738 trace_create_file("tracing_on", 0644, d_tracer
,
4739 &global_trace
, &rb_simple_fops
);
4741 #ifdef CONFIG_DYNAMIC_FTRACE
4742 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
4743 &ftrace_update_tot_cnt
, &tracing_dyn_info_fops
);
4746 create_trace_options_dir();
4748 for_each_tracing_cpu(cpu
)
4749 tracing_init_debugfs_percpu(cpu
);
4754 static int trace_panic_handler(struct notifier_block
*this,
4755 unsigned long event
, void *unused
)
4757 if (ftrace_dump_on_oops
)
4758 ftrace_dump(ftrace_dump_on_oops
);
4762 static struct notifier_block trace_panic_notifier
= {
4763 .notifier_call
= trace_panic_handler
,
4765 .priority
= 150 /* priority: INT_MAX >= x >= 0 */
4768 static int trace_die_handler(struct notifier_block
*self
,
4774 if (ftrace_dump_on_oops
)
4775 ftrace_dump(ftrace_dump_on_oops
);
4783 static struct notifier_block trace_die_notifier
= {
4784 .notifier_call
= trace_die_handler
,
4789 * printk is set to max of 1024, we really don't need it that big.
4790 * Nothing should be printing 1000 characters anyway.
4792 #define TRACE_MAX_PRINT 1000
4795 * Define here KERN_TRACE so that we have one place to modify
4796 * it if we decide to change what log level the ftrace dump
4799 #define KERN_TRACE KERN_EMERG
4802 trace_printk_seq(struct trace_seq
*s
)
4804 /* Probably should print a warning here. */
4808 /* should be zero ended, but we are paranoid. */
4809 s
->buffer
[s
->len
] = 0;
4811 printk(KERN_TRACE
"%s", s
->buffer
);
4816 void trace_init_global_iter(struct trace_iterator
*iter
)
4818 iter
->tr
= &global_trace
;
4819 iter
->trace
= current_trace
;
4820 iter
->cpu_file
= TRACE_PIPE_ALL_CPU
;
4824 __ftrace_dump(bool disable_tracing
, enum ftrace_dump_mode oops_dump_mode
)
4826 static arch_spinlock_t ftrace_dump_lock
=
4827 (arch_spinlock_t
)__ARCH_SPIN_LOCK_UNLOCKED
;
4828 /* use static because iter can be a bit big for the stack */
4829 static struct trace_iterator iter
;
4830 unsigned int old_userobj
;
4831 static int dump_ran
;
4832 unsigned long flags
;
4836 local_irq_save(flags
);
4837 arch_spin_lock(&ftrace_dump_lock
);
4845 /* Did function tracer already get disabled? */
4846 if (ftrace_is_dead()) {
4847 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
4848 printk("# MAY BE MISSING FUNCTION EVENTS\n");
4851 if (disable_tracing
)
4854 trace_init_global_iter(&iter
);
4856 for_each_tracing_cpu(cpu
) {
4857 atomic_inc(&iter
.tr
->data
[cpu
]->disabled
);
4860 old_userobj
= trace_flags
& TRACE_ITER_SYM_USEROBJ
;
4862 /* don't look at user memory in panic mode */
4863 trace_flags
&= ~TRACE_ITER_SYM_USEROBJ
;
4865 /* Simulate the iterator */
4866 iter
.tr
= &global_trace
;
4867 iter
.trace
= current_trace
;
4869 switch (oops_dump_mode
) {
4871 iter
.cpu_file
= TRACE_PIPE_ALL_CPU
;
4874 iter
.cpu_file
= raw_smp_processor_id();
4879 printk(KERN_TRACE
"Bad dumping mode, switching to all CPUs dump\n");
4880 iter
.cpu_file
= TRACE_PIPE_ALL_CPU
;
4883 printk(KERN_TRACE
"Dumping ftrace buffer:\n");
4886 * We need to stop all tracing on all CPUS to read the
4887 * the next buffer. This is a bit expensive, but is
4888 * not done often. We fill all what we can read,
4889 * and then release the locks again.
4892 while (!trace_empty(&iter
)) {
4895 printk(KERN_TRACE
"---------------------------------\n");
4899 /* reset all but tr, trace, and overruns */
4900 memset(&iter
.seq
, 0,
4901 sizeof(struct trace_iterator
) -
4902 offsetof(struct trace_iterator
, seq
));
4903 iter
.iter_flags
|= TRACE_FILE_LAT_FMT
;
4906 if (trace_find_next_entry_inc(&iter
) != NULL
) {
4909 ret
= print_trace_line(&iter
);
4910 if (ret
!= TRACE_TYPE_NO_CONSUME
)
4911 trace_consume(&iter
);
4913 touch_nmi_watchdog();
4915 trace_printk_seq(&iter
.seq
);
4919 printk(KERN_TRACE
" (ftrace buffer empty)\n");
4921 printk(KERN_TRACE
"---------------------------------\n");
4924 /* Re-enable tracing if requested */
4925 if (!disable_tracing
) {
4926 trace_flags
|= old_userobj
;
4928 for_each_tracing_cpu(cpu
) {
4929 atomic_dec(&iter
.tr
->data
[cpu
]->disabled
);
4935 arch_spin_unlock(&ftrace_dump_lock
);
4936 local_irq_restore(flags
);
4939 /* By default: disable tracing after the dump */
4940 void ftrace_dump(enum ftrace_dump_mode oops_dump_mode
)
4942 __ftrace_dump(true, oops_dump_mode
);
4944 EXPORT_SYMBOL_GPL(ftrace_dump
);
4946 __init
static int tracer_alloc_buffers(void)
4949 enum ring_buffer_flags rb_flags
;
4954 if (!alloc_cpumask_var(&tracing_buffer_mask
, GFP_KERNEL
))
4957 if (!alloc_cpumask_var(&tracing_cpumask
, GFP_KERNEL
))
4958 goto out_free_buffer_mask
;
4960 /* To save memory, keep the ring buffer size to its minimum */
4961 if (ring_buffer_expanded
)
4962 ring_buf_size
= trace_buf_size
;
4966 rb_flags
= trace_flags
& TRACE_ITER_OVERWRITE
? RB_FL_OVERWRITE
: 0;
4968 cpumask_copy(tracing_buffer_mask
, cpu_possible_mask
);
4969 cpumask_copy(tracing_cpumask
, cpu_all_mask
);
4971 /* TODO: make the number of buffers hot pluggable with CPUS */
4972 global_trace
.buffer
= ring_buffer_alloc(ring_buf_size
, rb_flags
);
4973 if (!global_trace
.buffer
) {
4974 printk(KERN_ERR
"tracer: failed to allocate ring buffer!\n");
4976 goto out_free_cpumask
;
4978 global_trace
.entries
= ring_buffer_size(global_trace
.buffer
);
4979 if (global_trace
.buffer_disabled
)
4983 #ifdef CONFIG_TRACER_MAX_TRACE
4984 max_tr
.buffer
= ring_buffer_alloc(1, rb_flags
);
4985 if (!max_tr
.buffer
) {
4986 printk(KERN_ERR
"tracer: failed to allocate max ring buffer!\n");
4988 ring_buffer_free(global_trace
.buffer
);
4989 goto out_free_cpumask
;
4994 /* Allocate the first page for all buffers */
4995 for_each_tracing_cpu(i
) {
4996 global_trace
.data
[i
] = &per_cpu(global_trace_cpu
, i
);
4997 max_tr
.data
[i
] = &per_cpu(max_tr_data
, i
);
5000 trace_init_cmdlines();
5002 register_tracer(&nop_trace
);
5003 current_trace
= &nop_trace
;
5004 /* All seems OK, enable tracing */
5005 tracing_disabled
= 0;
5007 atomic_notifier_chain_register(&panic_notifier_list
,
5008 &trace_panic_notifier
);
5010 register_die_notifier(&trace_die_notifier
);
5015 free_cpumask_var(tracing_cpumask
);
5016 out_free_buffer_mask
:
5017 free_cpumask_var(tracing_buffer_mask
);
5022 __init
static int clear_boot_tracer(void)
5025 * The default tracer at boot buffer is an init section.
5026 * This function is called in lateinit. If we did not
5027 * find the boot tracer, then clear it out, to prevent
5028 * later registration from accessing the buffer that is
5029 * about to be freed.
5031 if (!default_bootup_tracer
)
5034 printk(KERN_INFO
"ftrace bootup tracer '%s' not registered.\n",
5035 default_bootup_tracer
);
5036 default_bootup_tracer
= NULL
;
5041 early_initcall(tracer_alloc_buffers
);
5042 fs_initcall(tracer_init_debugfs
);
5043 late_initcall(clear_boot_tracer
);