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 cpumask_var_t __read_mostly tracing_buffer_mask
;
93 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
95 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
96 * is set, then ftrace_dump is called. This will output the contents
97 * of the ftrace buffers to the console. This is very useful for
98 * capturing traces that lead to crashes and outputing it to a
101 * It is default off, but you can enable it with either specifying
102 * "ftrace_dump_on_oops" in the kernel command line, or setting
103 * /proc/sys/kernel/ftrace_dump_on_oops
104 * Set 1 if you want to dump buffers of all CPUs
105 * Set 2 if you want to dump the buffer of the CPU that triggered oops
108 enum ftrace_dump_mode ftrace_dump_on_oops
;
110 static int tracing_set_tracer(const char *buf
);
112 #define MAX_TRACER_SIZE 100
113 static char bootup_tracer_buf
[MAX_TRACER_SIZE
] __initdata
;
114 static char *default_bootup_tracer
;
116 static int __init
set_cmdline_ftrace(char *str
)
118 strncpy(bootup_tracer_buf
, str
, MAX_TRACER_SIZE
);
119 default_bootup_tracer
= bootup_tracer_buf
;
120 /* We are using ftrace early, expand it */
121 ring_buffer_expanded
= 1;
124 __setup("ftrace=", set_cmdline_ftrace
);
126 static int __init
set_ftrace_dump_on_oops(char *str
)
128 if (*str
++ != '=' || !*str
) {
129 ftrace_dump_on_oops
= DUMP_ALL
;
133 if (!strcmp("orig_cpu", str
)) {
134 ftrace_dump_on_oops
= DUMP_ORIG
;
140 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops
);
142 unsigned long long ns2usecs(cycle_t nsec
)
150 * The global_trace is the descriptor that holds the tracing
151 * buffers for the live tracing. For each CPU, it contains
152 * a link list of pages that will store trace entries. The
153 * page descriptor of the pages in the memory is used to hold
154 * the link list by linking the lru item in the page descriptor
155 * to each of the pages in the buffer per CPU.
157 * For each active CPU there is a data field that holds the
158 * pages for the buffer for that CPU. Each CPU has the same number
159 * of pages allocated for its buffer.
161 static struct trace_array global_trace
;
163 static DEFINE_PER_CPU(struct trace_array_cpu
, global_trace_cpu
);
165 int filter_current_check_discard(struct ring_buffer
*buffer
,
166 struct ftrace_event_call
*call
, void *rec
,
167 struct ring_buffer_event
*event
)
169 return filter_check_discard(call
, rec
, buffer
, event
);
171 EXPORT_SYMBOL_GPL(filter_current_check_discard
);
173 cycle_t
ftrace_now(int cpu
)
177 /* Early boot up does not have a buffer yet */
178 if (!global_trace
.buffer
)
179 return trace_clock_local();
181 ts
= ring_buffer_time_stamp(global_trace
.buffer
, cpu
);
182 ring_buffer_normalize_time_stamp(global_trace
.buffer
, cpu
, &ts
);
188 * The max_tr is used to snapshot the global_trace when a maximum
189 * latency is reached. Some tracers will use this to store a maximum
190 * trace while it continues examining live traces.
192 * The buffers for the max_tr are set up the same as the global_trace.
193 * When a snapshot is taken, the link list of the max_tr is swapped
194 * with the link list of the global_trace and the buffers are reset for
195 * the global_trace so the tracing can continue.
197 static struct trace_array max_tr
;
199 static DEFINE_PER_CPU(struct trace_array_cpu
, max_tr_data
);
201 /* tracer_enabled is used to toggle activation of a tracer */
202 static int tracer_enabled
= 1;
205 * tracing_is_enabled - return tracer_enabled status
207 * This function is used by other tracers to know the status
208 * of the tracer_enabled flag. Tracers may use this function
209 * to know if it should enable their features when starting
210 * up. See irqsoff tracer for an example (start_irqsoff_tracer).
212 int tracing_is_enabled(void)
214 return tracer_enabled
;
218 * trace_buf_size is the size in bytes that is allocated
219 * for a buffer. Note, the number of bytes is always rounded
222 * This number is purposely set to a low number of 16384.
223 * If the dump on oops happens, it will be much appreciated
224 * to not have to wait for all that output. Anyway this can be
225 * boot time and run time configurable.
227 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
229 static unsigned long trace_buf_size
= TRACE_BUF_SIZE_DEFAULT
;
231 /* trace_types holds a link list of available tracers. */
232 static struct tracer
*trace_types __read_mostly
;
234 /* current_trace points to the tracer that is currently active */
235 static struct tracer
*current_trace __read_mostly
;
238 * trace_types_lock is used to protect the trace_types list.
240 static DEFINE_MUTEX(trace_types_lock
);
243 * serialize the access of the ring buffer
245 * ring buffer serializes readers, but it is low level protection.
246 * The validity of the events (which returns by ring_buffer_peek() ..etc)
247 * are not protected by ring buffer.
249 * The content of events may become garbage if we allow other process consumes
250 * these events concurrently:
251 * A) the page of the consumed events may become a normal page
252 * (not reader page) in ring buffer, and this page will be rewrited
253 * by events producer.
254 * B) The page of the consumed events may become a page for splice_read,
255 * and this page will be returned to system.
257 * These primitives allow multi process access to different cpu ring buffer
260 * These primitives don't distinguish read-only and read-consume access.
261 * Multi read-only access are also serialized.
265 static DECLARE_RWSEM(all_cpu_access_lock
);
266 static DEFINE_PER_CPU(struct mutex
, cpu_access_lock
);
268 static inline void trace_access_lock(int cpu
)
270 if (cpu
== TRACE_PIPE_ALL_CPU
) {
271 /* gain it for accessing the whole ring buffer. */
272 down_write(&all_cpu_access_lock
);
274 /* gain it for accessing a cpu ring buffer. */
276 /* Firstly block other trace_access_lock(TRACE_PIPE_ALL_CPU). */
277 down_read(&all_cpu_access_lock
);
279 /* Secondly block other access to this @cpu ring buffer. */
280 mutex_lock(&per_cpu(cpu_access_lock
, cpu
));
284 static inline void trace_access_unlock(int cpu
)
286 if (cpu
== TRACE_PIPE_ALL_CPU
) {
287 up_write(&all_cpu_access_lock
);
289 mutex_unlock(&per_cpu(cpu_access_lock
, cpu
));
290 up_read(&all_cpu_access_lock
);
294 static inline void trace_access_lock_init(void)
298 for_each_possible_cpu(cpu
)
299 mutex_init(&per_cpu(cpu_access_lock
, cpu
));
304 static DEFINE_MUTEX(access_lock
);
306 static inline void trace_access_lock(int cpu
)
309 mutex_lock(&access_lock
);
312 static inline void trace_access_unlock(int cpu
)
315 mutex_unlock(&access_lock
);
318 static inline void trace_access_lock_init(void)
324 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
325 static DECLARE_WAIT_QUEUE_HEAD(trace_wait
);
327 /* trace_flags holds trace_options default values */
328 unsigned long trace_flags
= TRACE_ITER_PRINT_PARENT
| TRACE_ITER_PRINTK
|
329 TRACE_ITER_ANNOTATE
| TRACE_ITER_CONTEXT_INFO
| TRACE_ITER_SLEEP_TIME
|
330 TRACE_ITER_GRAPH_TIME
| TRACE_ITER_RECORD_CMD
| TRACE_ITER_OVERWRITE
|
331 TRACE_ITER_IRQ_INFO
| TRACE_ITER_MARKERS
;
333 static int trace_stop_count
;
334 static DEFINE_RAW_SPINLOCK(tracing_start_lock
);
336 static void wakeup_work_handler(struct work_struct
*work
)
338 wake_up(&trace_wait
);
341 static DECLARE_DELAYED_WORK(wakeup_work
, wakeup_work_handler
);
344 * tracing_on - enable tracing buffers
346 * This function enables tracing buffers that may have been
347 * disabled with tracing_off.
349 void tracing_on(void)
351 if (global_trace
.buffer
)
352 ring_buffer_record_on(global_trace
.buffer
);
354 * This flag is only looked at when buffers haven't been
355 * allocated yet. We don't really care about the race
356 * between setting this flag and actually turning
359 global_trace
.buffer_disabled
= 0;
361 EXPORT_SYMBOL_GPL(tracing_on
);
364 * tracing_off - turn off tracing buffers
366 * This function stops the tracing buffers from recording data.
367 * It does not disable any overhead the tracers themselves may
368 * be causing. This function simply causes all recording to
369 * the ring buffers to fail.
371 void tracing_off(void)
373 if (global_trace
.buffer
)
374 ring_buffer_record_off(global_trace
.buffer
);
376 * This flag is only looked at when buffers haven't been
377 * allocated yet. We don't really care about the race
378 * between setting this flag and actually turning
381 global_trace
.buffer_disabled
= 1;
383 EXPORT_SYMBOL_GPL(tracing_off
);
386 * tracing_is_on - show state of ring buffers enabled
388 int tracing_is_on(void)
390 if (global_trace
.buffer
)
391 return ring_buffer_record_is_on(global_trace
.buffer
);
392 return !global_trace
.buffer_disabled
;
394 EXPORT_SYMBOL_GPL(tracing_is_on
);
397 * trace_wake_up - wake up tasks waiting for trace input
399 * Schedules a delayed work to wake up any task that is blocked on the
400 * trace_wait queue. These is used with trace_poll for tasks polling the
403 void trace_wake_up(void)
405 const unsigned long delay
= msecs_to_jiffies(2);
407 if (trace_flags
& TRACE_ITER_BLOCK
)
409 schedule_delayed_work(&wakeup_work
, delay
);
412 static int __init
set_buf_size(char *str
)
414 unsigned long buf_size
;
418 buf_size
= memparse(str
, &str
);
419 /* nr_entries can not be zero */
422 trace_buf_size
= buf_size
;
425 __setup("trace_buf_size=", set_buf_size
);
427 static int __init
set_tracing_thresh(char *str
)
429 unsigned long threshold
;
434 ret
= strict_strtoul(str
, 0, &threshold
);
437 tracing_thresh
= threshold
* 1000;
440 __setup("tracing_thresh=", set_tracing_thresh
);
442 unsigned long nsecs_to_usecs(unsigned long nsecs
)
447 /* These must match the bit postions in trace_iterator_flags */
448 static const char *trace_options
[] = {
481 { trace_clock_local
, "local" },
482 { trace_clock_global
, "global" },
483 { trace_clock_counter
, "counter" },
489 * trace_parser_get_init - gets the buffer for trace parser
491 int trace_parser_get_init(struct trace_parser
*parser
, int size
)
493 memset(parser
, 0, sizeof(*parser
));
495 parser
->buffer
= kmalloc(size
, GFP_KERNEL
);
504 * trace_parser_put - frees the buffer for trace parser
506 void trace_parser_put(struct trace_parser
*parser
)
508 kfree(parser
->buffer
);
512 * trace_get_user - reads the user input string separated by space
513 * (matched by isspace(ch))
515 * For each string found the 'struct trace_parser' is updated,
516 * and the function returns.
518 * Returns number of bytes read.
520 * See kernel/trace/trace.h for 'struct trace_parser' details.
522 int trace_get_user(struct trace_parser
*parser
, const char __user
*ubuf
,
523 size_t cnt
, loff_t
*ppos
)
530 trace_parser_clear(parser
);
532 ret
= get_user(ch
, ubuf
++);
540 * The parser is not finished with the last write,
541 * continue reading the user input without skipping spaces.
544 /* skip white space */
545 while (cnt
&& isspace(ch
)) {
546 ret
= get_user(ch
, ubuf
++);
553 /* only spaces were written */
563 /* read the non-space input */
564 while (cnt
&& !isspace(ch
)) {
565 if (parser
->idx
< parser
->size
- 1)
566 parser
->buffer
[parser
->idx
++] = ch
;
571 ret
= get_user(ch
, ubuf
++);
578 /* We either got finished input or we have to wait for another call. */
580 parser
->buffer
[parser
->idx
] = 0;
581 parser
->cont
= false;
584 parser
->buffer
[parser
->idx
++] = ch
;
594 ssize_t
trace_seq_to_user(struct trace_seq
*s
, char __user
*ubuf
, size_t cnt
)
602 if (s
->len
<= s
->readpos
)
605 len
= s
->len
- s
->readpos
;
608 ret
= copy_to_user(ubuf
, s
->buffer
+ s
->readpos
, cnt
);
618 static ssize_t
trace_seq_to_buffer(struct trace_seq
*s
, void *buf
, size_t cnt
)
622 if (s
->len
<= s
->readpos
)
625 len
= s
->len
- s
->readpos
;
628 memcpy(buf
, s
->buffer
+ s
->readpos
, cnt
);
635 * ftrace_max_lock is used to protect the swapping of buffers
636 * when taking a max snapshot. The buffers themselves are
637 * protected by per_cpu spinlocks. But the action of the swap
638 * needs its own lock.
640 * This is defined as a arch_spinlock_t in order to help
641 * with performance when lockdep debugging is enabled.
643 * It is also used in other places outside the update_max_tr
644 * so it needs to be defined outside of the
645 * CONFIG_TRACER_MAX_TRACE.
647 static arch_spinlock_t ftrace_max_lock
=
648 (arch_spinlock_t
)__ARCH_SPIN_LOCK_UNLOCKED
;
650 unsigned long __read_mostly tracing_thresh
;
652 #ifdef CONFIG_TRACER_MAX_TRACE
653 unsigned long __read_mostly tracing_max_latency
;
656 * Copy the new maximum trace into the separate maximum-trace
657 * structure. (this way the maximum trace is permanently saved,
658 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
661 __update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
663 struct trace_array_cpu
*data
= tr
->data
[cpu
];
664 struct trace_array_cpu
*max_data
;
667 max_tr
.time_start
= data
->preempt_timestamp
;
669 max_data
= max_tr
.data
[cpu
];
670 max_data
->saved_latency
= tracing_max_latency
;
671 max_data
->critical_start
= data
->critical_start
;
672 max_data
->critical_end
= data
->critical_end
;
674 memcpy(max_data
->comm
, tsk
->comm
, TASK_COMM_LEN
);
675 max_data
->pid
= tsk
->pid
;
676 max_data
->uid
= task_uid(tsk
);
677 max_data
->nice
= tsk
->static_prio
- 20 - MAX_RT_PRIO
;
678 max_data
->policy
= tsk
->policy
;
679 max_data
->rt_priority
= tsk
->rt_priority
;
681 /* record this tasks comm */
682 tracing_record_cmdline(tsk
);
686 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
688 * @tsk: the task with the latency
689 * @cpu: The cpu that initiated the trace.
691 * Flip the buffers between the @tr and the max_tr and record information
692 * about which task was the cause of this latency.
695 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
697 struct ring_buffer
*buf
= tr
->buffer
;
699 if (trace_stop_count
)
702 WARN_ON_ONCE(!irqs_disabled());
703 if (!current_trace
->use_max_tr
) {
707 arch_spin_lock(&ftrace_max_lock
);
709 tr
->buffer
= max_tr
.buffer
;
712 __update_max_tr(tr
, tsk
, cpu
);
713 arch_spin_unlock(&ftrace_max_lock
);
717 * update_max_tr_single - only copy one trace over, and reset the rest
719 * @tsk - task with the latency
720 * @cpu - the cpu of the buffer to copy.
722 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
725 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
729 if (trace_stop_count
)
732 WARN_ON_ONCE(!irqs_disabled());
733 if (!current_trace
->use_max_tr
) {
738 arch_spin_lock(&ftrace_max_lock
);
740 ret
= ring_buffer_swap_cpu(max_tr
.buffer
, tr
->buffer
, cpu
);
744 * We failed to swap the buffer due to a commit taking
745 * place on this CPU. We fail to record, but we reset
746 * the max trace buffer (no one writes directly to it)
747 * and flag that it failed.
749 trace_array_printk(&max_tr
, _THIS_IP_
,
750 "Failed to swap buffers due to commit in progress\n");
753 WARN_ON_ONCE(ret
&& ret
!= -EAGAIN
&& ret
!= -EBUSY
);
755 __update_max_tr(tr
, tsk
, cpu
);
756 arch_spin_unlock(&ftrace_max_lock
);
758 #endif /* CONFIG_TRACER_MAX_TRACE */
761 * register_tracer - register a tracer with the ftrace system.
762 * @type - the plugin for the tracer
764 * Register a new plugin tracer.
766 int register_tracer(struct tracer
*type
)
772 pr_info("Tracer must have a name\n");
776 if (strlen(type
->name
) >= MAX_TRACER_SIZE
) {
777 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE
);
781 mutex_lock(&trace_types_lock
);
783 tracing_selftest_running
= true;
785 for (t
= trace_types
; t
; t
= t
->next
) {
786 if (strcmp(type
->name
, t
->name
) == 0) {
788 pr_info("Tracer %s already registered\n",
796 type
->set_flag
= &dummy_set_flag
;
798 type
->flags
= &dummy_tracer_flags
;
800 if (!type
->flags
->opts
)
801 type
->flags
->opts
= dummy_tracer_opt
;
802 if (!type
->wait_pipe
)
803 type
->wait_pipe
= default_wait_pipe
;
806 #ifdef CONFIG_FTRACE_STARTUP_TEST
807 if (type
->selftest
&& !tracing_selftest_disabled
) {
808 struct tracer
*saved_tracer
= current_trace
;
809 struct trace_array
*tr
= &global_trace
;
812 * Run a selftest on this tracer.
813 * Here we reset the trace buffer, and set the current
814 * tracer to be this tracer. The tracer can then run some
815 * internal tracing to verify that everything is in order.
816 * If we fail, we do not register this tracer.
818 tracing_reset_online_cpus(tr
);
820 current_trace
= type
;
822 /* If we expanded the buffers, make sure the max is expanded too */
823 if (ring_buffer_expanded
&& type
->use_max_tr
)
824 ring_buffer_resize(max_tr
.buffer
, trace_buf_size
,
825 RING_BUFFER_ALL_CPUS
);
827 /* the test is responsible for initializing and enabling */
828 pr_info("Testing tracer %s: ", type
->name
);
829 ret
= type
->selftest(type
, tr
);
830 /* the test is responsible for resetting too */
831 current_trace
= saved_tracer
;
833 printk(KERN_CONT
"FAILED!\n");
834 /* Add the warning after printing 'FAILED' */
838 /* Only reset on passing, to avoid touching corrupted buffers */
839 tracing_reset_online_cpus(tr
);
841 /* Shrink the max buffer again */
842 if (ring_buffer_expanded
&& type
->use_max_tr
)
843 ring_buffer_resize(max_tr
.buffer
, 1,
844 RING_BUFFER_ALL_CPUS
);
846 printk(KERN_CONT
"PASSED\n");
850 type
->next
= trace_types
;
854 tracing_selftest_running
= false;
855 mutex_unlock(&trace_types_lock
);
857 if (ret
|| !default_bootup_tracer
)
860 if (strncmp(default_bootup_tracer
, type
->name
, MAX_TRACER_SIZE
))
863 printk(KERN_INFO
"Starting tracer '%s'\n", type
->name
);
864 /* Do we want this tracer to start on bootup? */
865 tracing_set_tracer(type
->name
);
866 default_bootup_tracer
= NULL
;
867 /* disable other selftests, since this will break it. */
868 tracing_selftest_disabled
= 1;
869 #ifdef CONFIG_FTRACE_STARTUP_TEST
870 printk(KERN_INFO
"Disabling FTRACE selftests due to running tracer '%s'\n",
878 void unregister_tracer(struct tracer
*type
)
882 mutex_lock(&trace_types_lock
);
883 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
887 pr_info("Tracer %s not registered\n", type
->name
);
893 if (type
== current_trace
&& tracer_enabled
) {
896 if (current_trace
->stop
)
897 current_trace
->stop(&global_trace
);
898 current_trace
= &nop_trace
;
901 mutex_unlock(&trace_types_lock
);
904 void tracing_reset(struct trace_array
*tr
, int cpu
)
906 struct ring_buffer
*buffer
= tr
->buffer
;
908 ring_buffer_record_disable(buffer
);
910 /* Make sure all commits have finished */
912 ring_buffer_reset_cpu(buffer
, cpu
);
914 ring_buffer_record_enable(buffer
);
917 void tracing_reset_online_cpus(struct trace_array
*tr
)
919 struct ring_buffer
*buffer
= tr
->buffer
;
922 ring_buffer_record_disable(buffer
);
924 /* Make sure all commits have finished */
927 tr
->time_start
= ftrace_now(tr
->cpu
);
929 for_each_online_cpu(cpu
)
930 ring_buffer_reset_cpu(buffer
, cpu
);
932 ring_buffer_record_enable(buffer
);
935 void tracing_reset_current(int cpu
)
937 tracing_reset(&global_trace
, cpu
);
940 void tracing_reset_current_online_cpus(void)
942 tracing_reset_online_cpus(&global_trace
);
945 #define SAVED_CMDLINES 128
946 #define NO_CMDLINE_MAP UINT_MAX
947 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
948 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
949 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
950 static int cmdline_idx
;
951 static arch_spinlock_t trace_cmdline_lock
= __ARCH_SPIN_LOCK_UNLOCKED
;
953 /* temporary disable recording */
954 static atomic_t trace_record_cmdline_disabled __read_mostly
;
956 static void trace_init_cmdlines(void)
958 memset(&map_pid_to_cmdline
, NO_CMDLINE_MAP
, sizeof(map_pid_to_cmdline
));
959 memset(&map_cmdline_to_pid
, NO_CMDLINE_MAP
, sizeof(map_cmdline_to_pid
));
963 int is_tracing_stopped(void)
965 return trace_stop_count
;
969 * ftrace_off_permanent - disable all ftrace code permanently
971 * This should only be called when a serious anomally has
972 * been detected. This will turn off the function tracing,
973 * ring buffers, and other tracing utilites. It takes no
974 * locks and can be called from any context.
976 void ftrace_off_permanent(void)
978 tracing_disabled
= 1;
980 tracing_off_permanent();
984 * tracing_start - quick start of the tracer
986 * If tracing is enabled but was stopped by tracing_stop,
987 * this will start the tracer back up.
989 void tracing_start(void)
991 struct ring_buffer
*buffer
;
994 if (tracing_disabled
)
997 raw_spin_lock_irqsave(&tracing_start_lock
, flags
);
998 if (--trace_stop_count
) {
999 if (trace_stop_count
< 0) {
1000 /* Someone screwed up their debugging */
1002 trace_stop_count
= 0;
1007 /* Prevent the buffers from switching */
1008 arch_spin_lock(&ftrace_max_lock
);
1010 buffer
= global_trace
.buffer
;
1012 ring_buffer_record_enable(buffer
);
1014 buffer
= max_tr
.buffer
;
1016 ring_buffer_record_enable(buffer
);
1018 arch_spin_unlock(&ftrace_max_lock
);
1022 raw_spin_unlock_irqrestore(&tracing_start_lock
, flags
);
1026 * tracing_stop - quick stop of the tracer
1028 * Light weight way to stop tracing. Use in conjunction with
1031 void tracing_stop(void)
1033 struct ring_buffer
*buffer
;
1034 unsigned long flags
;
1037 raw_spin_lock_irqsave(&tracing_start_lock
, flags
);
1038 if (trace_stop_count
++)
1041 /* Prevent the buffers from switching */
1042 arch_spin_lock(&ftrace_max_lock
);
1044 buffer
= global_trace
.buffer
;
1046 ring_buffer_record_disable(buffer
);
1048 buffer
= max_tr
.buffer
;
1050 ring_buffer_record_disable(buffer
);
1052 arch_spin_unlock(&ftrace_max_lock
);
1055 raw_spin_unlock_irqrestore(&tracing_start_lock
, flags
);
1058 void trace_stop_cmdline_recording(void);
1060 static void trace_save_cmdline(struct task_struct
*tsk
)
1064 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
1068 * It's not the end of the world if we don't get
1069 * the lock, but we also don't want to spin
1070 * nor do we want to disable interrupts,
1071 * so if we miss here, then better luck next time.
1073 if (!arch_spin_trylock(&trace_cmdline_lock
))
1076 idx
= map_pid_to_cmdline
[tsk
->pid
];
1077 if (idx
== NO_CMDLINE_MAP
) {
1078 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
1081 * Check whether the cmdline buffer at idx has a pid
1082 * mapped. We are going to overwrite that entry so we
1083 * need to clear the map_pid_to_cmdline. Otherwise we
1084 * would read the new comm for the old pid.
1086 pid
= map_cmdline_to_pid
[idx
];
1087 if (pid
!= NO_CMDLINE_MAP
)
1088 map_pid_to_cmdline
[pid
] = NO_CMDLINE_MAP
;
1090 map_cmdline_to_pid
[idx
] = tsk
->pid
;
1091 map_pid_to_cmdline
[tsk
->pid
] = idx
;
1096 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
1098 arch_spin_unlock(&trace_cmdline_lock
);
1101 void trace_find_cmdline(int pid
, char comm
[])
1106 strcpy(comm
, "<idle>");
1110 if (WARN_ON_ONCE(pid
< 0)) {
1111 strcpy(comm
, "<XXX>");
1115 if (pid
> PID_MAX_DEFAULT
) {
1116 strcpy(comm
, "<...>");
1121 arch_spin_lock(&trace_cmdline_lock
);
1122 map
= map_pid_to_cmdline
[pid
];
1123 if (map
!= NO_CMDLINE_MAP
)
1124 strcpy(comm
, saved_cmdlines
[map
]);
1126 strcpy(comm
, "<...>");
1128 arch_spin_unlock(&trace_cmdline_lock
);
1132 void tracing_record_cmdline(struct task_struct
*tsk
)
1134 if (atomic_read(&trace_record_cmdline_disabled
) || !tracer_enabled
||
1138 trace_save_cmdline(tsk
);
1142 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
,
1145 struct task_struct
*tsk
= current
;
1147 entry
->preempt_count
= pc
& 0xff;
1148 entry
->pid
= (tsk
) ? tsk
->pid
: 0;
1151 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1152 (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
1154 TRACE_FLAG_IRQS_NOSUPPORT
|
1156 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
1157 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
1158 (need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0);
1160 EXPORT_SYMBOL_GPL(tracing_generic_entry_update
);
1162 struct ring_buffer_event
*
1163 trace_buffer_lock_reserve(struct ring_buffer
*buffer
,
1166 unsigned long flags
, int pc
)
1168 struct ring_buffer_event
*event
;
1170 event
= ring_buffer_lock_reserve(buffer
, len
);
1171 if (event
!= NULL
) {
1172 struct trace_entry
*ent
= ring_buffer_event_data(event
);
1174 tracing_generic_entry_update(ent
, flags
, pc
);
1182 __trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1183 struct ring_buffer_event
*event
,
1184 unsigned long flags
, int pc
,
1187 ring_buffer_unlock_commit(buffer
, event
);
1189 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1190 ftrace_trace_userstack(buffer
, flags
, pc
);
1196 void trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1197 struct ring_buffer_event
*event
,
1198 unsigned long flags
, int pc
)
1200 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
, 1);
1203 struct ring_buffer_event
*
1204 trace_current_buffer_lock_reserve(struct ring_buffer
**current_rb
,
1205 int type
, unsigned long len
,
1206 unsigned long flags
, int pc
)
1208 *current_rb
= global_trace
.buffer
;
1209 return trace_buffer_lock_reserve(*current_rb
,
1210 type
, len
, flags
, pc
);
1212 EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve
);
1214 void trace_current_buffer_unlock_commit(struct ring_buffer
*buffer
,
1215 struct ring_buffer_event
*event
,
1216 unsigned long flags
, int pc
)
1218 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
, 1);
1220 EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit
);
1222 void trace_nowake_buffer_unlock_commit(struct ring_buffer
*buffer
,
1223 struct ring_buffer_event
*event
,
1224 unsigned long flags
, int pc
)
1226 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
, 0);
1228 EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit
);
1230 void trace_nowake_buffer_unlock_commit_regs(struct ring_buffer
*buffer
,
1231 struct ring_buffer_event
*event
,
1232 unsigned long flags
, int pc
,
1233 struct pt_regs
*regs
)
1235 ring_buffer_unlock_commit(buffer
, event
);
1237 ftrace_trace_stack_regs(buffer
, flags
, 0, pc
, regs
);
1238 ftrace_trace_userstack(buffer
, flags
, pc
);
1240 EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit_regs
);
1242 void trace_current_buffer_discard_commit(struct ring_buffer
*buffer
,
1243 struct ring_buffer_event
*event
)
1245 ring_buffer_discard_commit(buffer
, event
);
1247 EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit
);
1250 trace_function(struct trace_array
*tr
,
1251 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
1254 struct ftrace_event_call
*call
= &event_function
;
1255 struct ring_buffer
*buffer
= tr
->buffer
;
1256 struct ring_buffer_event
*event
;
1257 struct ftrace_entry
*entry
;
1259 /* If we are reading the ring buffer, don't trace */
1260 if (unlikely(__this_cpu_read(ftrace_cpu_disabled
)))
1263 event
= trace_buffer_lock_reserve(buffer
, TRACE_FN
, sizeof(*entry
),
1267 entry
= ring_buffer_event_data(event
);
1269 entry
->parent_ip
= parent_ip
;
1271 if (!filter_check_discard(call
, entry
, buffer
, event
))
1272 ring_buffer_unlock_commit(buffer
, event
);
1276 ftrace(struct trace_array
*tr
, struct trace_array_cpu
*data
,
1277 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
1280 if (likely(!atomic_read(&data
->disabled
)))
1281 trace_function(tr
, ip
, parent_ip
, flags
, pc
);
1284 #ifdef CONFIG_STACKTRACE
1286 #define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
1287 struct ftrace_stack
{
1288 unsigned long calls
[FTRACE_STACK_MAX_ENTRIES
];
1291 static DEFINE_PER_CPU(struct ftrace_stack
, ftrace_stack
);
1292 static DEFINE_PER_CPU(int, ftrace_stack_reserve
);
1294 static void __ftrace_trace_stack(struct ring_buffer
*buffer
,
1295 unsigned long flags
,
1296 int skip
, int pc
, struct pt_regs
*regs
)
1298 struct ftrace_event_call
*call
= &event_kernel_stack
;
1299 struct ring_buffer_event
*event
;
1300 struct stack_entry
*entry
;
1301 struct stack_trace trace
;
1303 int size
= FTRACE_STACK_ENTRIES
;
1305 trace
.nr_entries
= 0;
1309 * Since events can happen in NMIs there's no safe way to
1310 * use the per cpu ftrace_stacks. We reserve it and if an interrupt
1311 * or NMI comes in, it will just have to use the default
1312 * FTRACE_STACK_SIZE.
1314 preempt_disable_notrace();
1316 use_stack
= ++__get_cpu_var(ftrace_stack_reserve
);
1318 * We don't need any atomic variables, just a barrier.
1319 * If an interrupt comes in, we don't care, because it would
1320 * have exited and put the counter back to what we want.
1321 * We just need a barrier to keep gcc from moving things
1325 if (use_stack
== 1) {
1326 trace
.entries
= &__get_cpu_var(ftrace_stack
).calls
[0];
1327 trace
.max_entries
= FTRACE_STACK_MAX_ENTRIES
;
1330 save_stack_trace_regs(regs
, &trace
);
1332 save_stack_trace(&trace
);
1334 if (trace
.nr_entries
> size
)
1335 size
= trace
.nr_entries
;
1337 /* From now on, use_stack is a boolean */
1340 size
*= sizeof(unsigned long);
1342 event
= trace_buffer_lock_reserve(buffer
, TRACE_STACK
,
1343 sizeof(*entry
) + size
, flags
, pc
);
1346 entry
= ring_buffer_event_data(event
);
1348 memset(&entry
->caller
, 0, size
);
1351 memcpy(&entry
->caller
, trace
.entries
,
1352 trace
.nr_entries
* sizeof(unsigned long));
1354 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1355 trace
.entries
= entry
->caller
;
1357 save_stack_trace_regs(regs
, &trace
);
1359 save_stack_trace(&trace
);
1362 entry
->size
= trace
.nr_entries
;
1364 if (!filter_check_discard(call
, entry
, buffer
, event
))
1365 ring_buffer_unlock_commit(buffer
, event
);
1368 /* Again, don't let gcc optimize things here */
1370 __get_cpu_var(ftrace_stack_reserve
)--;
1371 preempt_enable_notrace();
1375 void ftrace_trace_stack_regs(struct ring_buffer
*buffer
, unsigned long flags
,
1376 int skip
, int pc
, struct pt_regs
*regs
)
1378 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1381 __ftrace_trace_stack(buffer
, flags
, skip
, pc
, regs
);
1384 void ftrace_trace_stack(struct ring_buffer
*buffer
, unsigned long flags
,
1387 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1390 __ftrace_trace_stack(buffer
, flags
, skip
, pc
, NULL
);
1393 void __trace_stack(struct trace_array
*tr
, unsigned long flags
, int skip
,
1396 __ftrace_trace_stack(tr
->buffer
, flags
, skip
, pc
, NULL
);
1400 * trace_dump_stack - record a stack back trace in the trace buffer
1402 void trace_dump_stack(void)
1404 unsigned long flags
;
1406 if (tracing_disabled
|| tracing_selftest_running
)
1409 local_save_flags(flags
);
1411 /* skipping 3 traces, seems to get us at the caller of this function */
1412 __ftrace_trace_stack(global_trace
.buffer
, flags
, 3, preempt_count(), NULL
);
1415 static DEFINE_PER_CPU(int, user_stack_count
);
1418 ftrace_trace_userstack(struct ring_buffer
*buffer
, unsigned long flags
, int pc
)
1420 struct ftrace_event_call
*call
= &event_user_stack
;
1421 struct ring_buffer_event
*event
;
1422 struct userstack_entry
*entry
;
1423 struct stack_trace trace
;
1425 if (!(trace_flags
& TRACE_ITER_USERSTACKTRACE
))
1429 * NMIs can not handle page faults, even with fix ups.
1430 * The save user stack can (and often does) fault.
1432 if (unlikely(in_nmi()))
1436 * prevent recursion, since the user stack tracing may
1437 * trigger other kernel events.
1440 if (__this_cpu_read(user_stack_count
))
1443 __this_cpu_inc(user_stack_count
);
1445 event
= trace_buffer_lock_reserve(buffer
, TRACE_USER_STACK
,
1446 sizeof(*entry
), flags
, pc
);
1448 goto out_drop_count
;
1449 entry
= ring_buffer_event_data(event
);
1451 entry
->tgid
= current
->tgid
;
1452 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
1454 trace
.nr_entries
= 0;
1455 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1457 trace
.entries
= entry
->caller
;
1459 save_stack_trace_user(&trace
);
1460 if (!filter_check_discard(call
, entry
, buffer
, event
))
1461 ring_buffer_unlock_commit(buffer
, event
);
1464 __this_cpu_dec(user_stack_count
);
1470 static void __trace_userstack(struct trace_array
*tr
, unsigned long flags
)
1472 ftrace_trace_userstack(tr
, flags
, preempt_count());
1476 #endif /* CONFIG_STACKTRACE */
1478 /* created for use with alloc_percpu */
1479 struct trace_buffer_struct
{
1480 char buffer
[TRACE_BUF_SIZE
];
1483 static struct trace_buffer_struct
*trace_percpu_buffer
;
1484 static struct trace_buffer_struct
*trace_percpu_sirq_buffer
;
1485 static struct trace_buffer_struct
*trace_percpu_irq_buffer
;
1486 static struct trace_buffer_struct
*trace_percpu_nmi_buffer
;
1489 * The buffer used is dependent on the context. There is a per cpu
1490 * buffer for normal context, softirq contex, hard irq context and
1491 * for NMI context. Thise allows for lockless recording.
1493 * Note, if the buffers failed to be allocated, then this returns NULL
1495 static char *get_trace_buf(void)
1497 struct trace_buffer_struct
*percpu_buffer
;
1498 struct trace_buffer_struct
*buffer
;
1501 * If we have allocated per cpu buffers, then we do not
1502 * need to do any locking.
1505 percpu_buffer
= trace_percpu_nmi_buffer
;
1507 percpu_buffer
= trace_percpu_irq_buffer
;
1508 else if (in_softirq())
1509 percpu_buffer
= trace_percpu_sirq_buffer
;
1511 percpu_buffer
= trace_percpu_buffer
;
1516 buffer
= per_cpu_ptr(percpu_buffer
, smp_processor_id());
1518 return buffer
->buffer
;
1521 static int alloc_percpu_trace_buffer(void)
1523 struct trace_buffer_struct
*buffers
;
1524 struct trace_buffer_struct
*sirq_buffers
;
1525 struct trace_buffer_struct
*irq_buffers
;
1526 struct trace_buffer_struct
*nmi_buffers
;
1528 buffers
= alloc_percpu(struct trace_buffer_struct
);
1532 sirq_buffers
= alloc_percpu(struct trace_buffer_struct
);
1536 irq_buffers
= alloc_percpu(struct trace_buffer_struct
);
1540 nmi_buffers
= alloc_percpu(struct trace_buffer_struct
);
1544 trace_percpu_buffer
= buffers
;
1545 trace_percpu_sirq_buffer
= sirq_buffers
;
1546 trace_percpu_irq_buffer
= irq_buffers
;
1547 trace_percpu_nmi_buffer
= nmi_buffers
;
1552 free_percpu(irq_buffers
);
1554 free_percpu(sirq_buffers
);
1556 free_percpu(buffers
);
1558 WARN(1, "Could not allocate percpu trace_printk buffer");
1562 void trace_printk_init_buffers(void)
1564 static int buffers_allocated
;
1566 if (buffers_allocated
)
1569 if (alloc_percpu_trace_buffer())
1572 pr_info("ftrace: Allocated trace_printk buffers\n");
1574 buffers_allocated
= 1;
1578 * trace_vbprintk - write binary msg to tracing buffer
1581 int trace_vbprintk(unsigned long ip
, const char *fmt
, va_list args
)
1583 struct ftrace_event_call
*call
= &event_bprint
;
1584 struct ring_buffer_event
*event
;
1585 struct ring_buffer
*buffer
;
1586 struct trace_array
*tr
= &global_trace
;
1587 struct bprint_entry
*entry
;
1588 unsigned long flags
;
1590 int len
= 0, size
, pc
;
1592 if (unlikely(tracing_selftest_running
|| tracing_disabled
))
1595 /* Don't pollute graph traces with trace_vprintk internals */
1596 pause_graph_tracing();
1598 pc
= preempt_count();
1599 preempt_disable_notrace();
1601 tbuffer
= get_trace_buf();
1607 len
= vbin_printf((u32
*)tbuffer
, TRACE_BUF_SIZE
/sizeof(int), fmt
, args
);
1609 if (len
> TRACE_BUF_SIZE
/sizeof(int) || len
< 0)
1612 local_save_flags(flags
);
1613 size
= sizeof(*entry
) + sizeof(u32
) * len
;
1614 buffer
= tr
->buffer
;
1615 event
= trace_buffer_lock_reserve(buffer
, TRACE_BPRINT
, size
,
1619 entry
= ring_buffer_event_data(event
);
1623 memcpy(entry
->buf
, tbuffer
, sizeof(u32
) * len
);
1624 if (!filter_check_discard(call
, entry
, buffer
, event
)) {
1625 ring_buffer_unlock_commit(buffer
, event
);
1626 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1630 preempt_enable_notrace();
1631 unpause_graph_tracing();
1635 EXPORT_SYMBOL_GPL(trace_vbprintk
);
1637 int trace_array_printk(struct trace_array
*tr
,
1638 unsigned long ip
, const char *fmt
, ...)
1643 if (!(trace_flags
& TRACE_ITER_PRINTK
))
1647 ret
= trace_array_vprintk(tr
, ip
, fmt
, ap
);
1652 int trace_array_vprintk(struct trace_array
*tr
,
1653 unsigned long ip
, const char *fmt
, va_list args
)
1655 struct ftrace_event_call
*call
= &event_print
;
1656 struct ring_buffer_event
*event
;
1657 struct ring_buffer
*buffer
;
1658 int len
= 0, size
, pc
;
1659 struct print_entry
*entry
;
1660 unsigned long flags
;
1663 if (tracing_disabled
|| tracing_selftest_running
)
1666 /* Don't pollute graph traces with trace_vprintk internals */
1667 pause_graph_tracing();
1669 pc
= preempt_count();
1670 preempt_disable_notrace();
1673 tbuffer
= get_trace_buf();
1679 len
= vsnprintf(tbuffer
, TRACE_BUF_SIZE
, fmt
, args
);
1680 if (len
> TRACE_BUF_SIZE
)
1683 local_save_flags(flags
);
1684 size
= sizeof(*entry
) + len
+ 1;
1685 buffer
= tr
->buffer
;
1686 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, size
,
1690 entry
= ring_buffer_event_data(event
);
1693 memcpy(&entry
->buf
, tbuffer
, len
);
1694 entry
->buf
[len
] = '\0';
1695 if (!filter_check_discard(call
, entry
, buffer
, event
)) {
1696 ring_buffer_unlock_commit(buffer
, event
);
1697 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1700 preempt_enable_notrace();
1701 unpause_graph_tracing();
1706 int trace_vprintk(unsigned long ip
, const char *fmt
, va_list args
)
1708 return trace_array_vprintk(&global_trace
, ip
, fmt
, args
);
1710 EXPORT_SYMBOL_GPL(trace_vprintk
);
1712 static void trace_iterator_increment(struct trace_iterator
*iter
)
1714 struct ring_buffer_iter
*buf_iter
= trace_buffer_iter(iter
, iter
->cpu
);
1718 ring_buffer_read(buf_iter
, NULL
);
1721 static struct trace_entry
*
1722 peek_next_entry(struct trace_iterator
*iter
, int cpu
, u64
*ts
,
1723 unsigned long *lost_events
)
1725 struct ring_buffer_event
*event
;
1726 struct ring_buffer_iter
*buf_iter
= trace_buffer_iter(iter
, cpu
);
1729 event
= ring_buffer_iter_peek(buf_iter
, ts
);
1731 event
= ring_buffer_peek(iter
->tr
->buffer
, cpu
, ts
,
1735 iter
->ent_size
= ring_buffer_event_length(event
);
1736 return ring_buffer_event_data(event
);
1742 static struct trace_entry
*
1743 __find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
,
1744 unsigned long *missing_events
, u64
*ent_ts
)
1746 struct ring_buffer
*buffer
= iter
->tr
->buffer
;
1747 struct trace_entry
*ent
, *next
= NULL
;
1748 unsigned long lost_events
= 0, next_lost
= 0;
1749 int cpu_file
= iter
->cpu_file
;
1750 u64 next_ts
= 0, ts
;
1756 * If we are in a per_cpu trace file, don't bother by iterating over
1757 * all cpu and peek directly.
1759 if (cpu_file
> TRACE_PIPE_ALL_CPU
) {
1760 if (ring_buffer_empty_cpu(buffer
, cpu_file
))
1762 ent
= peek_next_entry(iter
, cpu_file
, ent_ts
, missing_events
);
1764 *ent_cpu
= cpu_file
;
1769 for_each_tracing_cpu(cpu
) {
1771 if (ring_buffer_empty_cpu(buffer
, cpu
))
1774 ent
= peek_next_entry(iter
, cpu
, &ts
, &lost_events
);
1777 * Pick the entry with the smallest timestamp:
1779 if (ent
&& (!next
|| ts
< next_ts
)) {
1783 next_lost
= lost_events
;
1784 next_size
= iter
->ent_size
;
1788 iter
->ent_size
= next_size
;
1791 *ent_cpu
= next_cpu
;
1797 *missing_events
= next_lost
;
1802 /* Find the next real entry, without updating the iterator itself */
1803 struct trace_entry
*trace_find_next_entry(struct trace_iterator
*iter
,
1804 int *ent_cpu
, u64
*ent_ts
)
1806 return __find_next_entry(iter
, ent_cpu
, NULL
, ent_ts
);
1809 /* Find the next real entry, and increment the iterator to the next entry */
1810 void *trace_find_next_entry_inc(struct trace_iterator
*iter
)
1812 iter
->ent
= __find_next_entry(iter
, &iter
->cpu
,
1813 &iter
->lost_events
, &iter
->ts
);
1816 trace_iterator_increment(iter
);
1818 return iter
->ent
? iter
: NULL
;
1821 static void trace_consume(struct trace_iterator
*iter
)
1823 ring_buffer_consume(iter
->tr
->buffer
, iter
->cpu
, &iter
->ts
,
1824 &iter
->lost_events
);
1827 static void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1829 struct trace_iterator
*iter
= m
->private;
1833 WARN_ON_ONCE(iter
->leftover
);
1837 /* can't go backwards */
1842 ent
= trace_find_next_entry_inc(iter
);
1846 while (ent
&& iter
->idx
< i
)
1847 ent
= trace_find_next_entry_inc(iter
);
1854 void tracing_iter_reset(struct trace_iterator
*iter
, int cpu
)
1856 struct trace_array
*tr
= iter
->tr
;
1857 struct ring_buffer_event
*event
;
1858 struct ring_buffer_iter
*buf_iter
;
1859 unsigned long entries
= 0;
1862 tr
->data
[cpu
]->skipped_entries
= 0;
1864 buf_iter
= trace_buffer_iter(iter
, cpu
);
1868 ring_buffer_iter_reset(buf_iter
);
1871 * We could have the case with the max latency tracers
1872 * that a reset never took place on a cpu. This is evident
1873 * by the timestamp being before the start of the buffer.
1875 while ((event
= ring_buffer_iter_peek(buf_iter
, &ts
))) {
1876 if (ts
>= iter
->tr
->time_start
)
1879 ring_buffer_read(buf_iter
, NULL
);
1882 tr
->data
[cpu
]->skipped_entries
= entries
;
1886 * The current tracer is copied to avoid a global locking
1889 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
1891 struct trace_iterator
*iter
= m
->private;
1892 static struct tracer
*old_tracer
;
1893 int cpu_file
= iter
->cpu_file
;
1898 /* copy the tracer to avoid using a global lock all around */
1899 mutex_lock(&trace_types_lock
);
1900 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
1901 old_tracer
= current_trace
;
1902 *iter
->trace
= *current_trace
;
1904 mutex_unlock(&trace_types_lock
);
1906 atomic_inc(&trace_record_cmdline_disabled
);
1908 if (*pos
!= iter
->pos
) {
1913 if (cpu_file
== TRACE_PIPE_ALL_CPU
) {
1914 for_each_tracing_cpu(cpu
)
1915 tracing_iter_reset(iter
, cpu
);
1917 tracing_iter_reset(iter
, cpu_file
);
1920 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
1925 * If we overflowed the seq_file before, then we want
1926 * to just reuse the trace_seq buffer again.
1932 p
= s_next(m
, p
, &l
);
1936 trace_event_read_lock();
1937 trace_access_lock(cpu_file
);
1941 static void s_stop(struct seq_file
*m
, void *p
)
1943 struct trace_iterator
*iter
= m
->private;
1945 atomic_dec(&trace_record_cmdline_disabled
);
1946 trace_access_unlock(iter
->cpu_file
);
1947 trace_event_read_unlock();
1951 get_total_entries(struct trace_array
*tr
, unsigned long *total
, unsigned long *entries
)
1953 unsigned long count
;
1959 for_each_tracing_cpu(cpu
) {
1960 count
= ring_buffer_entries_cpu(tr
->buffer
, cpu
);
1962 * If this buffer has skipped entries, then we hold all
1963 * entries for the trace and we need to ignore the
1964 * ones before the time stamp.
1966 if (tr
->data
[cpu
]->skipped_entries
) {
1967 count
-= tr
->data
[cpu
]->skipped_entries
;
1968 /* total is the same as the entries */
1972 ring_buffer_overrun_cpu(tr
->buffer
, cpu
);
1977 static void print_lat_help_header(struct seq_file
*m
)
1979 seq_puts(m
, "# _------=> CPU# \n");
1980 seq_puts(m
, "# / _-----=> irqs-off \n");
1981 seq_puts(m
, "# | / _----=> need-resched \n");
1982 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
1983 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
1984 seq_puts(m
, "# |||| / delay \n");
1985 seq_puts(m
, "# cmd pid ||||| time | caller \n");
1986 seq_puts(m
, "# \\ / ||||| \\ | / \n");
1989 static void print_event_info(struct trace_array
*tr
, struct seq_file
*m
)
1991 unsigned long total
;
1992 unsigned long entries
;
1994 get_total_entries(tr
, &total
, &entries
);
1995 seq_printf(m
, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
1996 entries
, total
, num_online_cpus());
2000 static void print_func_help_header(struct trace_array
*tr
, struct seq_file
*m
)
2002 print_event_info(tr
, m
);
2003 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
2004 seq_puts(m
, "# | | | | |\n");
2007 static void print_func_help_header_irq(struct trace_array
*tr
, struct seq_file
*m
)
2009 print_event_info(tr
, m
);
2010 seq_puts(m
, "# _-----=> irqs-off\n");
2011 seq_puts(m
, "# / _----=> need-resched\n");
2012 seq_puts(m
, "# | / _---=> hardirq/softirq\n");
2013 seq_puts(m
, "# || / _--=> preempt-depth\n");
2014 seq_puts(m
, "# ||| / delay\n");
2015 seq_puts(m
, "# TASK-PID CPU# |||| TIMESTAMP FUNCTION\n");
2016 seq_puts(m
, "# | | | |||| | |\n");
2020 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
2022 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
2023 struct trace_array
*tr
= iter
->tr
;
2024 struct trace_array_cpu
*data
= tr
->data
[tr
->cpu
];
2025 struct tracer
*type
= current_trace
;
2026 unsigned long entries
;
2027 unsigned long total
;
2028 const char *name
= "preemption";
2033 get_total_entries(tr
, &total
, &entries
);
2035 seq_printf(m
, "# %s latency trace v1.1.5 on %s\n",
2037 seq_puts(m
, "# -----------------------------------"
2038 "---------------------------------\n");
2039 seq_printf(m
, "# latency: %lu us, #%lu/%lu, CPU#%d |"
2040 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
2041 nsecs_to_usecs(data
->saved_latency
),
2045 #if defined(CONFIG_PREEMPT_NONE)
2047 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
2049 #elif defined(CONFIG_PREEMPT)
2054 /* These are reserved for later use */
2057 seq_printf(m
, " #P:%d)\n", num_online_cpus());
2061 seq_puts(m
, "# -----------------\n");
2062 seq_printf(m
, "# | task: %.16s-%d "
2063 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
2064 data
->comm
, data
->pid
,
2065 from_kuid_munged(seq_user_ns(m
), data
->uid
), data
->nice
,
2066 data
->policy
, data
->rt_priority
);
2067 seq_puts(m
, "# -----------------\n");
2069 if (data
->critical_start
) {
2070 seq_puts(m
, "# => started at: ");
2071 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
2072 trace_print_seq(m
, &iter
->seq
);
2073 seq_puts(m
, "\n# => ended at: ");
2074 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
2075 trace_print_seq(m
, &iter
->seq
);
2076 seq_puts(m
, "\n#\n");
2082 static void test_cpu_buff_start(struct trace_iterator
*iter
)
2084 struct trace_seq
*s
= &iter
->seq
;
2086 if (!(trace_flags
& TRACE_ITER_ANNOTATE
))
2089 if (!(iter
->iter_flags
& TRACE_FILE_ANNOTATE
))
2092 if (cpumask_test_cpu(iter
->cpu
, iter
->started
))
2095 if (iter
->tr
->data
[iter
->cpu
]->skipped_entries
)
2098 cpumask_set_cpu(iter
->cpu
, iter
->started
);
2100 /* Don't print started cpu buffer for the first entry of the trace */
2102 trace_seq_printf(s
, "##### CPU %u buffer started ####\n",
2106 static enum print_line_t
print_trace_fmt(struct trace_iterator
*iter
)
2108 struct trace_seq
*s
= &iter
->seq
;
2109 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
2110 struct trace_entry
*entry
;
2111 struct trace_event
*event
;
2115 test_cpu_buff_start(iter
);
2117 event
= ftrace_find_event(entry
->type
);
2119 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2120 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
2121 if (!trace_print_lat_context(iter
))
2124 if (!trace_print_context(iter
))
2130 return event
->funcs
->trace(iter
, sym_flags
, event
);
2132 if (!trace_seq_printf(s
, "Unknown type %d\n", entry
->type
))
2135 return TRACE_TYPE_HANDLED
;
2137 return TRACE_TYPE_PARTIAL_LINE
;
2140 static enum print_line_t
print_raw_fmt(struct trace_iterator
*iter
)
2142 struct trace_seq
*s
= &iter
->seq
;
2143 struct trace_entry
*entry
;
2144 struct trace_event
*event
;
2148 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2149 if (!trace_seq_printf(s
, "%d %d %llu ",
2150 entry
->pid
, iter
->cpu
, iter
->ts
))
2154 event
= ftrace_find_event(entry
->type
);
2156 return event
->funcs
->raw(iter
, 0, event
);
2158 if (!trace_seq_printf(s
, "%d ?\n", entry
->type
))
2161 return TRACE_TYPE_HANDLED
;
2163 return TRACE_TYPE_PARTIAL_LINE
;
2166 static enum print_line_t
print_hex_fmt(struct trace_iterator
*iter
)
2168 struct trace_seq
*s
= &iter
->seq
;
2169 unsigned char newline
= '\n';
2170 struct trace_entry
*entry
;
2171 struct trace_event
*event
;
2175 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2176 SEQ_PUT_HEX_FIELD_RET(s
, entry
->pid
);
2177 SEQ_PUT_HEX_FIELD_RET(s
, iter
->cpu
);
2178 SEQ_PUT_HEX_FIELD_RET(s
, iter
->ts
);
2181 event
= ftrace_find_event(entry
->type
);
2183 enum print_line_t ret
= event
->funcs
->hex(iter
, 0, event
);
2184 if (ret
!= TRACE_TYPE_HANDLED
)
2188 SEQ_PUT_FIELD_RET(s
, newline
);
2190 return TRACE_TYPE_HANDLED
;
2193 static enum print_line_t
print_bin_fmt(struct trace_iterator
*iter
)
2195 struct trace_seq
*s
= &iter
->seq
;
2196 struct trace_entry
*entry
;
2197 struct trace_event
*event
;
2201 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2202 SEQ_PUT_FIELD_RET(s
, entry
->pid
);
2203 SEQ_PUT_FIELD_RET(s
, iter
->cpu
);
2204 SEQ_PUT_FIELD_RET(s
, iter
->ts
);
2207 event
= ftrace_find_event(entry
->type
);
2208 return event
? event
->funcs
->binary(iter
, 0, event
) :
2212 int trace_empty(struct trace_iterator
*iter
)
2214 struct ring_buffer_iter
*buf_iter
;
2217 /* If we are looking at one CPU buffer, only check that one */
2218 if (iter
->cpu_file
!= TRACE_PIPE_ALL_CPU
) {
2219 cpu
= iter
->cpu_file
;
2220 buf_iter
= trace_buffer_iter(iter
, cpu
);
2222 if (!ring_buffer_iter_empty(buf_iter
))
2225 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
2231 for_each_tracing_cpu(cpu
) {
2232 buf_iter
= trace_buffer_iter(iter
, cpu
);
2234 if (!ring_buffer_iter_empty(buf_iter
))
2237 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
2245 /* Called with trace_event_read_lock() held. */
2246 enum print_line_t
print_trace_line(struct trace_iterator
*iter
)
2248 enum print_line_t ret
;
2250 if (iter
->lost_events
&&
2251 !trace_seq_printf(&iter
->seq
, "CPU:%d [LOST %lu EVENTS]\n",
2252 iter
->cpu
, iter
->lost_events
))
2253 return TRACE_TYPE_PARTIAL_LINE
;
2255 if (iter
->trace
&& iter
->trace
->print_line
) {
2256 ret
= iter
->trace
->print_line(iter
);
2257 if (ret
!= TRACE_TYPE_UNHANDLED
)
2261 if (iter
->ent
->type
== TRACE_BPRINT
&&
2262 trace_flags
& TRACE_ITER_PRINTK
&&
2263 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2264 return trace_print_bprintk_msg_only(iter
);
2266 if (iter
->ent
->type
== TRACE_PRINT
&&
2267 trace_flags
& TRACE_ITER_PRINTK
&&
2268 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2269 return trace_print_printk_msg_only(iter
);
2271 if (trace_flags
& TRACE_ITER_BIN
)
2272 return print_bin_fmt(iter
);
2274 if (trace_flags
& TRACE_ITER_HEX
)
2275 return print_hex_fmt(iter
);
2277 if (trace_flags
& TRACE_ITER_RAW
)
2278 return print_raw_fmt(iter
);
2280 return print_trace_fmt(iter
);
2283 void trace_latency_header(struct seq_file
*m
)
2285 struct trace_iterator
*iter
= m
->private;
2287 /* print nothing if the buffers are empty */
2288 if (trace_empty(iter
))
2291 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
)
2292 print_trace_header(m
, iter
);
2294 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2295 print_lat_help_header(m
);
2298 void trace_default_header(struct seq_file
*m
)
2300 struct trace_iterator
*iter
= m
->private;
2302 if (!(trace_flags
& TRACE_ITER_CONTEXT_INFO
))
2305 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
2306 /* print nothing if the buffers are empty */
2307 if (trace_empty(iter
))
2309 print_trace_header(m
, iter
);
2310 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2311 print_lat_help_header(m
);
2313 if (!(trace_flags
& TRACE_ITER_VERBOSE
)) {
2314 if (trace_flags
& TRACE_ITER_IRQ_INFO
)
2315 print_func_help_header_irq(iter
->tr
, m
);
2317 print_func_help_header(iter
->tr
, m
);
2322 static void test_ftrace_alive(struct seq_file
*m
)
2324 if (!ftrace_is_dead())
2326 seq_printf(m
, "# WARNING: FUNCTION TRACING IS CORRUPTED\n");
2327 seq_printf(m
, "# MAY BE MISSING FUNCTION EVENTS\n");
2330 static int s_show(struct seq_file
*m
, void *v
)
2332 struct trace_iterator
*iter
= v
;
2335 if (iter
->ent
== NULL
) {
2337 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
2339 test_ftrace_alive(m
);
2341 if (iter
->trace
&& iter
->trace
->print_header
)
2342 iter
->trace
->print_header(m
);
2344 trace_default_header(m
);
2346 } else if (iter
->leftover
) {
2348 * If we filled the seq_file buffer earlier, we
2349 * want to just show it now.
2351 ret
= trace_print_seq(m
, &iter
->seq
);
2353 /* ret should this time be zero, but you never know */
2354 iter
->leftover
= ret
;
2357 print_trace_line(iter
);
2358 ret
= trace_print_seq(m
, &iter
->seq
);
2360 * If we overflow the seq_file buffer, then it will
2361 * ask us for this data again at start up.
2363 * ret is 0 if seq_file write succeeded.
2366 iter
->leftover
= ret
;
2372 static const struct seq_operations tracer_seq_ops
= {
2379 static struct trace_iterator
*
2380 __tracing_open(struct inode
*inode
, struct file
*file
)
2382 long cpu_file
= (long) inode
->i_private
;
2383 struct trace_iterator
*iter
;
2386 if (tracing_disabled
)
2387 return ERR_PTR(-ENODEV
);
2389 iter
= __seq_open_private(file
, &tracer_seq_ops
, sizeof(*iter
));
2391 return ERR_PTR(-ENOMEM
);
2393 iter
->buffer_iter
= kzalloc(sizeof(*iter
->buffer_iter
) * num_possible_cpus(),
2395 if (!iter
->buffer_iter
)
2399 * We make a copy of the current tracer to avoid concurrent
2400 * changes on it while we are reading.
2402 mutex_lock(&trace_types_lock
);
2403 iter
->trace
= kzalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
2408 *iter
->trace
= *current_trace
;
2410 if (!zalloc_cpumask_var(&iter
->started
, GFP_KERNEL
))
2413 if (current_trace
&& current_trace
->print_max
)
2416 iter
->tr
= &global_trace
;
2418 mutex_init(&iter
->mutex
);
2419 iter
->cpu_file
= cpu_file
;
2421 /* Notify the tracer early; before we stop tracing. */
2422 if (iter
->trace
&& iter
->trace
->open
)
2423 iter
->trace
->open(iter
);
2425 /* Annotate start of buffers if we had overruns */
2426 if (ring_buffer_overruns(iter
->tr
->buffer
))
2427 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
2429 /* stop the trace while dumping */
2432 if (iter
->cpu_file
== TRACE_PIPE_ALL_CPU
) {
2433 for_each_tracing_cpu(cpu
) {
2434 iter
->buffer_iter
[cpu
] =
2435 ring_buffer_read_prepare(iter
->tr
->buffer
, cpu
);
2437 ring_buffer_read_prepare_sync();
2438 for_each_tracing_cpu(cpu
) {
2439 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2440 tracing_iter_reset(iter
, cpu
);
2443 cpu
= iter
->cpu_file
;
2444 iter
->buffer_iter
[cpu
] =
2445 ring_buffer_read_prepare(iter
->tr
->buffer
, cpu
);
2446 ring_buffer_read_prepare_sync();
2447 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2448 tracing_iter_reset(iter
, cpu
);
2451 mutex_unlock(&trace_types_lock
);
2456 mutex_unlock(&trace_types_lock
);
2458 kfree(iter
->buffer_iter
);
2460 seq_release_private(inode
, file
);
2461 return ERR_PTR(-ENOMEM
);
2464 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
2466 if (tracing_disabled
)
2469 filp
->private_data
= inode
->i_private
;
2473 static int tracing_release(struct inode
*inode
, struct file
*file
)
2475 struct seq_file
*m
= file
->private_data
;
2476 struct trace_iterator
*iter
;
2479 if (!(file
->f_mode
& FMODE_READ
))
2484 mutex_lock(&trace_types_lock
);
2485 for_each_tracing_cpu(cpu
) {
2486 if (iter
->buffer_iter
[cpu
])
2487 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
2490 if (iter
->trace
&& iter
->trace
->close
)
2491 iter
->trace
->close(iter
);
2493 /* reenable tracing if it was previously enabled */
2495 mutex_unlock(&trace_types_lock
);
2497 mutex_destroy(&iter
->mutex
);
2498 free_cpumask_var(iter
->started
);
2500 kfree(iter
->buffer_iter
);
2501 seq_release_private(inode
, file
);
2505 static int tracing_open(struct inode
*inode
, struct file
*file
)
2507 struct trace_iterator
*iter
;
2510 /* If this file was open for write, then erase contents */
2511 if ((file
->f_mode
& FMODE_WRITE
) &&
2512 (file
->f_flags
& O_TRUNC
)) {
2513 long cpu
= (long) inode
->i_private
;
2515 if (cpu
== TRACE_PIPE_ALL_CPU
)
2516 tracing_reset_online_cpus(&global_trace
);
2518 tracing_reset(&global_trace
, cpu
);
2521 if (file
->f_mode
& FMODE_READ
) {
2522 iter
= __tracing_open(inode
, file
);
2524 ret
= PTR_ERR(iter
);
2525 else if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
2526 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
2532 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
2534 struct tracer
*t
= v
;
2544 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
2549 mutex_lock(&trace_types_lock
);
2550 for (t
= trace_types
; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
2556 static void t_stop(struct seq_file
*m
, void *p
)
2558 mutex_unlock(&trace_types_lock
);
2561 static int t_show(struct seq_file
*m
, void *v
)
2563 struct tracer
*t
= v
;
2568 seq_printf(m
, "%s", t
->name
);
2577 static const struct seq_operations show_traces_seq_ops
= {
2584 static int show_traces_open(struct inode
*inode
, struct file
*file
)
2586 if (tracing_disabled
)
2589 return seq_open(file
, &show_traces_seq_ops
);
2593 tracing_write_stub(struct file
*filp
, const char __user
*ubuf
,
2594 size_t count
, loff_t
*ppos
)
2599 static loff_t
tracing_seek(struct file
*file
, loff_t offset
, int origin
)
2601 if (file
->f_mode
& FMODE_READ
)
2602 return seq_lseek(file
, offset
, origin
);
2607 static const struct file_operations tracing_fops
= {
2608 .open
= tracing_open
,
2610 .write
= tracing_write_stub
,
2611 .llseek
= tracing_seek
,
2612 .release
= tracing_release
,
2615 static const struct file_operations show_traces_fops
= {
2616 .open
= show_traces_open
,
2618 .release
= seq_release
,
2619 .llseek
= seq_lseek
,
2623 * Only trace on a CPU if the bitmask is set:
2625 static cpumask_var_t tracing_cpumask
;
2628 * The tracer itself will not take this lock, but still we want
2629 * to provide a consistent cpumask to user-space:
2631 static DEFINE_MUTEX(tracing_cpumask_update_lock
);
2634 * Temporary storage for the character representation of the
2635 * CPU bitmask (and one more byte for the newline):
2637 static char mask_str
[NR_CPUS
+ 1];
2640 tracing_cpumask_read(struct file
*filp
, char __user
*ubuf
,
2641 size_t count
, loff_t
*ppos
)
2645 mutex_lock(&tracing_cpumask_update_lock
);
2647 len
= cpumask_scnprintf(mask_str
, count
, tracing_cpumask
);
2648 if (count
- len
< 2) {
2652 len
+= sprintf(mask_str
+ len
, "\n");
2653 count
= simple_read_from_buffer(ubuf
, count
, ppos
, mask_str
, NR_CPUS
+1);
2656 mutex_unlock(&tracing_cpumask_update_lock
);
2662 tracing_cpumask_write(struct file
*filp
, const char __user
*ubuf
,
2663 size_t count
, loff_t
*ppos
)
2666 cpumask_var_t tracing_cpumask_new
;
2668 if (!alloc_cpumask_var(&tracing_cpumask_new
, GFP_KERNEL
))
2671 err
= cpumask_parse_user(ubuf
, count
, tracing_cpumask_new
);
2675 mutex_lock(&tracing_cpumask_update_lock
);
2677 local_irq_disable();
2678 arch_spin_lock(&ftrace_max_lock
);
2679 for_each_tracing_cpu(cpu
) {
2681 * Increase/decrease the disabled counter if we are
2682 * about to flip a bit in the cpumask:
2684 if (cpumask_test_cpu(cpu
, tracing_cpumask
) &&
2685 !cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
2686 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
2687 ring_buffer_record_disable_cpu(global_trace
.buffer
, cpu
);
2689 if (!cpumask_test_cpu(cpu
, tracing_cpumask
) &&
2690 cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
2691 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
2692 ring_buffer_record_enable_cpu(global_trace
.buffer
, cpu
);
2695 arch_spin_unlock(&ftrace_max_lock
);
2698 cpumask_copy(tracing_cpumask
, tracing_cpumask_new
);
2700 mutex_unlock(&tracing_cpumask_update_lock
);
2701 free_cpumask_var(tracing_cpumask_new
);
2706 free_cpumask_var(tracing_cpumask_new
);
2711 static const struct file_operations tracing_cpumask_fops
= {
2712 .open
= tracing_open_generic
,
2713 .read
= tracing_cpumask_read
,
2714 .write
= tracing_cpumask_write
,
2715 .llseek
= generic_file_llseek
,
2718 static int tracing_trace_options_show(struct seq_file
*m
, void *v
)
2720 struct tracer_opt
*trace_opts
;
2724 mutex_lock(&trace_types_lock
);
2725 tracer_flags
= current_trace
->flags
->val
;
2726 trace_opts
= current_trace
->flags
->opts
;
2728 for (i
= 0; trace_options
[i
]; i
++) {
2729 if (trace_flags
& (1 << i
))
2730 seq_printf(m
, "%s\n", trace_options
[i
]);
2732 seq_printf(m
, "no%s\n", trace_options
[i
]);
2735 for (i
= 0; trace_opts
[i
].name
; i
++) {
2736 if (tracer_flags
& trace_opts
[i
].bit
)
2737 seq_printf(m
, "%s\n", trace_opts
[i
].name
);
2739 seq_printf(m
, "no%s\n", trace_opts
[i
].name
);
2741 mutex_unlock(&trace_types_lock
);
2746 static int __set_tracer_option(struct tracer
*trace
,
2747 struct tracer_flags
*tracer_flags
,
2748 struct tracer_opt
*opts
, int neg
)
2752 ret
= trace
->set_flag(tracer_flags
->val
, opts
->bit
, !neg
);
2757 tracer_flags
->val
&= ~opts
->bit
;
2759 tracer_flags
->val
|= opts
->bit
;
2763 /* Try to assign a tracer specific option */
2764 static int set_tracer_option(struct tracer
*trace
, char *cmp
, int neg
)
2766 struct tracer_flags
*tracer_flags
= trace
->flags
;
2767 struct tracer_opt
*opts
= NULL
;
2770 for (i
= 0; tracer_flags
->opts
[i
].name
; i
++) {
2771 opts
= &tracer_flags
->opts
[i
];
2773 if (strcmp(cmp
, opts
->name
) == 0)
2774 return __set_tracer_option(trace
, trace
->flags
,
2781 static void set_tracer_flags(unsigned int mask
, int enabled
)
2783 /* do nothing if flag is already set */
2784 if (!!(trace_flags
& mask
) == !!enabled
)
2788 trace_flags
|= mask
;
2790 trace_flags
&= ~mask
;
2792 if (mask
== TRACE_ITER_RECORD_CMD
)
2793 trace_event_enable_cmd_record(enabled
);
2795 if (mask
== TRACE_ITER_OVERWRITE
)
2796 ring_buffer_change_overwrite(global_trace
.buffer
, enabled
);
2800 tracing_trace_options_write(struct file
*filp
, const char __user
*ubuf
,
2801 size_t cnt
, loff_t
*ppos
)
2809 if (cnt
>= sizeof(buf
))
2812 if (copy_from_user(&buf
, ubuf
, cnt
))
2816 cmp
= strstrip(buf
);
2818 if (strncmp(cmp
, "no", 2) == 0) {
2823 for (i
= 0; trace_options
[i
]; i
++) {
2824 if (strcmp(cmp
, trace_options
[i
]) == 0) {
2825 set_tracer_flags(1 << i
, !neg
);
2830 /* If no option could be set, test the specific tracer options */
2831 if (!trace_options
[i
]) {
2832 mutex_lock(&trace_types_lock
);
2833 ret
= set_tracer_option(current_trace
, cmp
, neg
);
2834 mutex_unlock(&trace_types_lock
);
2844 static int tracing_trace_options_open(struct inode
*inode
, struct file
*file
)
2846 if (tracing_disabled
)
2848 return single_open(file
, tracing_trace_options_show
, NULL
);
2851 static const struct file_operations tracing_iter_fops
= {
2852 .open
= tracing_trace_options_open
,
2854 .llseek
= seq_lseek
,
2855 .release
= single_release
,
2856 .write
= tracing_trace_options_write
,
2859 static const char readme_msg
[] =
2860 "tracing mini-HOWTO:\n\n"
2861 "# mount -t debugfs nodev /sys/kernel/debug\n\n"
2862 "# cat /sys/kernel/debug/tracing/available_tracers\n"
2863 "wakeup wakeup_rt preemptirqsoff preemptoff irqsoff function nop\n\n"
2864 "# cat /sys/kernel/debug/tracing/current_tracer\n"
2866 "# echo wakeup > /sys/kernel/debug/tracing/current_tracer\n"
2867 "# cat /sys/kernel/debug/tracing/current_tracer\n"
2869 "# cat /sys/kernel/debug/tracing/trace_options\n"
2870 "noprint-parent nosym-offset nosym-addr noverbose\n"
2871 "# echo print-parent > /sys/kernel/debug/tracing/trace_options\n"
2872 "# echo 1 > /sys/kernel/debug/tracing/tracing_on\n"
2873 "# cat /sys/kernel/debug/tracing/trace > /tmp/trace.txt\n"
2874 "# echo 0 > /sys/kernel/debug/tracing/tracing_on\n"
2878 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
2879 size_t cnt
, loff_t
*ppos
)
2881 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
2882 readme_msg
, strlen(readme_msg
));
2885 static const struct file_operations tracing_readme_fops
= {
2886 .open
= tracing_open_generic
,
2887 .read
= tracing_readme_read
,
2888 .llseek
= generic_file_llseek
,
2892 tracing_saved_cmdlines_read(struct file
*file
, char __user
*ubuf
,
2893 size_t cnt
, loff_t
*ppos
)
2902 file_buf
= kmalloc(SAVED_CMDLINES
*(16+TASK_COMM_LEN
), GFP_KERNEL
);
2906 buf_comm
= kmalloc(TASK_COMM_LEN
, GFP_KERNEL
);
2914 for (i
= 0; i
< SAVED_CMDLINES
; i
++) {
2917 pid
= map_cmdline_to_pid
[i
];
2918 if (pid
== -1 || pid
== NO_CMDLINE_MAP
)
2921 trace_find_cmdline(pid
, buf_comm
);
2922 r
= sprintf(buf
, "%d %s\n", pid
, buf_comm
);
2927 len
= simple_read_from_buffer(ubuf
, cnt
, ppos
,
2936 static const struct file_operations tracing_saved_cmdlines_fops
= {
2937 .open
= tracing_open_generic
,
2938 .read
= tracing_saved_cmdlines_read
,
2939 .llseek
= generic_file_llseek
,
2943 tracing_ctrl_read(struct file
*filp
, char __user
*ubuf
,
2944 size_t cnt
, loff_t
*ppos
)
2949 r
= sprintf(buf
, "%u\n", tracer_enabled
);
2950 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2954 tracing_ctrl_write(struct file
*filp
, const char __user
*ubuf
,
2955 size_t cnt
, loff_t
*ppos
)
2957 struct trace_array
*tr
= filp
->private_data
;
2961 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
2967 mutex_lock(&trace_types_lock
);
2968 if (tracer_enabled
^ val
) {
2970 /* Only need to warn if this is used to change the state */
2971 WARN_ONCE(1, "tracing_enabled is deprecated. Use tracing_on");
2975 if (current_trace
->start
)
2976 current_trace
->start(tr
);
2981 if (current_trace
->stop
)
2982 current_trace
->stop(tr
);
2985 mutex_unlock(&trace_types_lock
);
2993 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
2994 size_t cnt
, loff_t
*ppos
)
2996 char buf
[MAX_TRACER_SIZE
+2];
2999 mutex_lock(&trace_types_lock
);
3001 r
= sprintf(buf
, "%s\n", current_trace
->name
);
3003 r
= sprintf(buf
, "\n");
3004 mutex_unlock(&trace_types_lock
);
3006 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3009 int tracer_init(struct tracer
*t
, struct trace_array
*tr
)
3011 tracing_reset_online_cpus(tr
);
3015 static void set_buffer_entries(struct trace_array
*tr
, unsigned long val
)
3018 for_each_tracing_cpu(cpu
)
3019 tr
->data
[cpu
]->entries
= val
;
3022 static int __tracing_resize_ring_buffer(unsigned long size
, int cpu
)
3027 * If kernel or user changes the size of the ring buffer
3028 * we use the size that was given, and we can forget about
3029 * expanding it later.
3031 ring_buffer_expanded
= 1;
3033 ret
= ring_buffer_resize(global_trace
.buffer
, size
, cpu
);
3037 if (!current_trace
->use_max_tr
)
3040 ret
= ring_buffer_resize(max_tr
.buffer
, size
, cpu
);
3044 if (cpu
== RING_BUFFER_ALL_CPUS
) {
3046 for_each_tracing_cpu(i
) {
3047 r
= ring_buffer_resize(global_trace
.buffer
,
3048 global_trace
.data
[i
]->entries
,
3054 r
= ring_buffer_resize(global_trace
.buffer
,
3055 global_trace
.data
[cpu
]->entries
,
3061 * AARGH! We are left with different
3062 * size max buffer!!!!
3063 * The max buffer is our "snapshot" buffer.
3064 * When a tracer needs a snapshot (one of the
3065 * latency tracers), it swaps the max buffer
3066 * with the saved snap shot. We succeeded to
3067 * update the size of the main buffer, but failed to
3068 * update the size of the max buffer. But when we tried
3069 * to reset the main buffer to the original size, we
3070 * failed there too. This is very unlikely to
3071 * happen, but if it does, warn and kill all
3075 tracing_disabled
= 1;
3080 if (cpu
== RING_BUFFER_ALL_CPUS
)
3081 set_buffer_entries(&max_tr
, size
);
3083 max_tr
.data
[cpu
]->entries
= size
;
3086 if (cpu
== RING_BUFFER_ALL_CPUS
)
3087 set_buffer_entries(&global_trace
, size
);
3089 global_trace
.data
[cpu
]->entries
= size
;
3094 static ssize_t
tracing_resize_ring_buffer(unsigned long size
, int cpu_id
)
3098 mutex_lock(&trace_types_lock
);
3100 if (cpu_id
!= RING_BUFFER_ALL_CPUS
) {
3101 /* make sure, this cpu is enabled in the mask */
3102 if (!cpumask_test_cpu(cpu_id
, tracing_buffer_mask
)) {
3108 ret
= __tracing_resize_ring_buffer(size
, cpu_id
);
3113 mutex_unlock(&trace_types_lock
);
3120 * tracing_update_buffers - used by tracing facility to expand ring buffers
3122 * To save on memory when the tracing is never used on a system with it
3123 * configured in. The ring buffers are set to a minimum size. But once
3124 * a user starts to use the tracing facility, then they need to grow
3125 * to their default size.
3127 * This function is to be called when a tracer is about to be used.
3129 int tracing_update_buffers(void)
3133 mutex_lock(&trace_types_lock
);
3134 if (!ring_buffer_expanded
)
3135 ret
= __tracing_resize_ring_buffer(trace_buf_size
,
3136 RING_BUFFER_ALL_CPUS
);
3137 mutex_unlock(&trace_types_lock
);
3142 struct trace_option_dentry
;
3144 static struct trace_option_dentry
*
3145 create_trace_option_files(struct tracer
*tracer
);
3148 destroy_trace_option_files(struct trace_option_dentry
*topts
);
3150 static int tracing_set_tracer(const char *buf
)
3152 static struct trace_option_dentry
*topts
;
3153 struct trace_array
*tr
= &global_trace
;
3157 mutex_lock(&trace_types_lock
);
3159 if (!ring_buffer_expanded
) {
3160 ret
= __tracing_resize_ring_buffer(trace_buf_size
,
3161 RING_BUFFER_ALL_CPUS
);
3167 for (t
= trace_types
; t
; t
= t
->next
) {
3168 if (strcmp(t
->name
, buf
) == 0)
3175 if (t
== current_trace
)
3178 trace_branch_disable();
3179 if (current_trace
&& current_trace
->reset
)
3180 current_trace
->reset(tr
);
3181 if (current_trace
&& current_trace
->use_max_tr
) {
3183 * We don't free the ring buffer. instead, resize it because
3184 * The max_tr ring buffer has some state (e.g. ring->clock) and
3185 * we want preserve it.
3187 ring_buffer_resize(max_tr
.buffer
, 1, RING_BUFFER_ALL_CPUS
);
3188 set_buffer_entries(&max_tr
, 1);
3190 destroy_trace_option_files(topts
);
3192 current_trace
= &nop_trace
;
3194 topts
= create_trace_option_files(t
);
3195 if (t
->use_max_tr
) {
3197 /* we need to make per cpu buffer sizes equivalent */
3198 for_each_tracing_cpu(cpu
) {
3199 ret
= ring_buffer_resize(max_tr
.buffer
,
3200 global_trace
.data
[cpu
]->entries
,
3204 max_tr
.data
[cpu
]->entries
=
3205 global_trace
.data
[cpu
]->entries
;
3210 ret
= tracer_init(t
, tr
);
3216 trace_branch_enable(tr
);
3218 mutex_unlock(&trace_types_lock
);
3224 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
3225 size_t cnt
, loff_t
*ppos
)
3227 char buf
[MAX_TRACER_SIZE
+1];
3234 if (cnt
> MAX_TRACER_SIZE
)
3235 cnt
= MAX_TRACER_SIZE
;
3237 if (copy_from_user(&buf
, ubuf
, cnt
))
3242 /* strip ending whitespace. */
3243 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
3246 err
= tracing_set_tracer(buf
);
3256 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
3257 size_t cnt
, loff_t
*ppos
)
3259 unsigned long *ptr
= filp
->private_data
;
3263 r
= snprintf(buf
, sizeof(buf
), "%ld\n",
3264 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
3265 if (r
> sizeof(buf
))
3267 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3271 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
3272 size_t cnt
, loff_t
*ppos
)
3274 unsigned long *ptr
= filp
->private_data
;
3278 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
3287 static int tracing_open_pipe(struct inode
*inode
, struct file
*filp
)
3289 long cpu_file
= (long) inode
->i_private
;
3290 struct trace_iterator
*iter
;
3293 if (tracing_disabled
)
3296 mutex_lock(&trace_types_lock
);
3298 /* create a buffer to store the information to pass to userspace */
3299 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
3306 * We make a copy of the current tracer to avoid concurrent
3307 * changes on it while we are reading.
3309 iter
->trace
= kmalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
3315 *iter
->trace
= *current_trace
;
3317 if (!alloc_cpumask_var(&iter
->started
, GFP_KERNEL
)) {
3322 /* trace pipe does not show start of buffer */
3323 cpumask_setall(iter
->started
);
3325 if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
3326 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
3328 iter
->cpu_file
= cpu_file
;
3329 iter
->tr
= &global_trace
;
3330 mutex_init(&iter
->mutex
);
3331 filp
->private_data
= iter
;
3333 if (iter
->trace
->pipe_open
)
3334 iter
->trace
->pipe_open(iter
);
3336 nonseekable_open(inode
, filp
);
3338 mutex_unlock(&trace_types_lock
);
3344 mutex_unlock(&trace_types_lock
);
3348 static int tracing_release_pipe(struct inode
*inode
, struct file
*file
)
3350 struct trace_iterator
*iter
= file
->private_data
;
3352 mutex_lock(&trace_types_lock
);
3354 if (iter
->trace
->pipe_close
)
3355 iter
->trace
->pipe_close(iter
);
3357 mutex_unlock(&trace_types_lock
);
3359 free_cpumask_var(iter
->started
);
3360 mutex_destroy(&iter
->mutex
);
3368 tracing_poll_pipe(struct file
*filp
, poll_table
*poll_table
)
3370 struct trace_iterator
*iter
= filp
->private_data
;
3372 if (trace_flags
& TRACE_ITER_BLOCK
) {
3374 * Always select as readable when in blocking mode
3376 return POLLIN
| POLLRDNORM
;
3378 if (!trace_empty(iter
))
3379 return POLLIN
| POLLRDNORM
;
3380 poll_wait(filp
, &trace_wait
, poll_table
);
3381 if (!trace_empty(iter
))
3382 return POLLIN
| POLLRDNORM
;
3389 void default_wait_pipe(struct trace_iterator
*iter
)
3393 prepare_to_wait(&trace_wait
, &wait
, TASK_INTERRUPTIBLE
);
3395 if (trace_empty(iter
))
3398 finish_wait(&trace_wait
, &wait
);
3402 * This is a make-shift waitqueue.
3403 * A tracer might use this callback on some rare cases:
3405 * 1) the current tracer might hold the runqueue lock when it wakes up
3406 * a reader, hence a deadlock (sched, function, and function graph tracers)
3407 * 2) the function tracers, trace all functions, we don't want
3408 * the overhead of calling wake_up and friends
3409 * (and tracing them too)
3411 * Anyway, this is really very primitive wakeup.
3413 void poll_wait_pipe(struct trace_iterator
*iter
)
3415 set_current_state(TASK_INTERRUPTIBLE
);
3416 /* sleep for 100 msecs, and try again. */
3417 schedule_timeout(HZ
/ 10);
3420 /* Must be called with trace_types_lock mutex held. */
3421 static int tracing_wait_pipe(struct file
*filp
)
3423 struct trace_iterator
*iter
= filp
->private_data
;
3425 while (trace_empty(iter
)) {
3427 if ((filp
->f_flags
& O_NONBLOCK
)) {
3431 mutex_unlock(&iter
->mutex
);
3433 iter
->trace
->wait_pipe(iter
);
3435 mutex_lock(&iter
->mutex
);
3437 if (signal_pending(current
))
3441 * We block until we read something and tracing is disabled.
3442 * We still block if tracing is disabled, but we have never
3443 * read anything. This allows a user to cat this file, and
3444 * then enable tracing. But after we have read something,
3445 * we give an EOF when tracing is again disabled.
3447 * iter->pos will be 0 if we haven't read anything.
3449 if (!tracer_enabled
&& iter
->pos
)
3460 tracing_read_pipe(struct file
*filp
, char __user
*ubuf
,
3461 size_t cnt
, loff_t
*ppos
)
3463 struct trace_iterator
*iter
= filp
->private_data
;
3464 static struct tracer
*old_tracer
;
3467 /* return any leftover data */
3468 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
3472 trace_seq_init(&iter
->seq
);
3474 /* copy the tracer to avoid using a global lock all around */
3475 mutex_lock(&trace_types_lock
);
3476 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
3477 old_tracer
= current_trace
;
3478 *iter
->trace
= *current_trace
;
3480 mutex_unlock(&trace_types_lock
);
3483 * Avoid more than one consumer on a single file descriptor
3484 * This is just a matter of traces coherency, the ring buffer itself
3487 mutex_lock(&iter
->mutex
);
3488 if (iter
->trace
->read
) {
3489 sret
= iter
->trace
->read(iter
, filp
, ubuf
, cnt
, ppos
);
3495 sret
= tracing_wait_pipe(filp
);
3499 /* stop when tracing is finished */
3500 if (trace_empty(iter
)) {
3505 if (cnt
>= PAGE_SIZE
)
3506 cnt
= PAGE_SIZE
- 1;
3508 /* reset all but tr, trace, and overruns */
3509 memset(&iter
->seq
, 0,
3510 sizeof(struct trace_iterator
) -
3511 offsetof(struct trace_iterator
, seq
));
3514 trace_event_read_lock();
3515 trace_access_lock(iter
->cpu_file
);
3516 while (trace_find_next_entry_inc(iter
) != NULL
) {
3517 enum print_line_t ret
;
3518 int len
= iter
->seq
.len
;
3520 ret
= print_trace_line(iter
);
3521 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
3522 /* don't print partial lines */
3523 iter
->seq
.len
= len
;
3526 if (ret
!= TRACE_TYPE_NO_CONSUME
)
3527 trace_consume(iter
);
3529 if (iter
->seq
.len
>= cnt
)
3533 * Setting the full flag means we reached the trace_seq buffer
3534 * size and we should leave by partial output condition above.
3535 * One of the trace_seq_* functions is not used properly.
3537 WARN_ONCE(iter
->seq
.full
, "full flag set for trace type %d",
3540 trace_access_unlock(iter
->cpu_file
);
3541 trace_event_read_unlock();
3543 /* Now copy what we have to the user */
3544 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
3545 if (iter
->seq
.readpos
>= iter
->seq
.len
)
3546 trace_seq_init(&iter
->seq
);
3549 * If there was nothing to send to user, in spite of consuming trace
3550 * entries, go back to wait for more entries.
3556 mutex_unlock(&iter
->mutex
);
3561 static void tracing_pipe_buf_release(struct pipe_inode_info
*pipe
,
3562 struct pipe_buffer
*buf
)
3564 __free_page(buf
->page
);
3567 static void tracing_spd_release_pipe(struct splice_pipe_desc
*spd
,
3570 __free_page(spd
->pages
[idx
]);
3573 static const struct pipe_buf_operations tracing_pipe_buf_ops
= {
3575 .map
= generic_pipe_buf_map
,
3576 .unmap
= generic_pipe_buf_unmap
,
3577 .confirm
= generic_pipe_buf_confirm
,
3578 .release
= tracing_pipe_buf_release
,
3579 .steal
= generic_pipe_buf_steal
,
3580 .get
= generic_pipe_buf_get
,
3584 tracing_fill_pipe_page(size_t rem
, struct trace_iterator
*iter
)
3589 /* Seq buffer is page-sized, exactly what we need. */
3591 count
= iter
->seq
.len
;
3592 ret
= print_trace_line(iter
);
3593 count
= iter
->seq
.len
- count
;
3596 iter
->seq
.len
-= count
;
3599 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
3600 iter
->seq
.len
-= count
;
3604 if (ret
!= TRACE_TYPE_NO_CONSUME
)
3605 trace_consume(iter
);
3607 if (!trace_find_next_entry_inc(iter
)) {
3617 static ssize_t
tracing_splice_read_pipe(struct file
*filp
,
3619 struct pipe_inode_info
*pipe
,
3623 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
3624 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
3625 struct trace_iterator
*iter
= filp
->private_data
;
3626 struct splice_pipe_desc spd
= {
3628 .partial
= partial_def
,
3629 .nr_pages
= 0, /* This gets updated below. */
3630 .nr_pages_max
= PIPE_DEF_BUFFERS
,
3632 .ops
= &tracing_pipe_buf_ops
,
3633 .spd_release
= tracing_spd_release_pipe
,
3635 static struct tracer
*old_tracer
;
3640 if (splice_grow_spd(pipe
, &spd
))
3643 /* copy the tracer to avoid using a global lock all around */
3644 mutex_lock(&trace_types_lock
);
3645 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
3646 old_tracer
= current_trace
;
3647 *iter
->trace
= *current_trace
;
3649 mutex_unlock(&trace_types_lock
);
3651 mutex_lock(&iter
->mutex
);
3653 if (iter
->trace
->splice_read
) {
3654 ret
= iter
->trace
->splice_read(iter
, filp
,
3655 ppos
, pipe
, len
, flags
);
3660 ret
= tracing_wait_pipe(filp
);
3664 if (!iter
->ent
&& !trace_find_next_entry_inc(iter
)) {
3669 trace_event_read_lock();
3670 trace_access_lock(iter
->cpu_file
);
3672 /* Fill as many pages as possible. */
3673 for (i
= 0, rem
= len
; i
< pipe
->buffers
&& rem
; i
++) {
3674 spd
.pages
[i
] = alloc_page(GFP_KERNEL
);
3678 rem
= tracing_fill_pipe_page(rem
, iter
);
3680 /* Copy the data into the page, so we can start over. */
3681 ret
= trace_seq_to_buffer(&iter
->seq
,
3682 page_address(spd
.pages
[i
]),
3685 __free_page(spd
.pages
[i
]);
3688 spd
.partial
[i
].offset
= 0;
3689 spd
.partial
[i
].len
= iter
->seq
.len
;
3691 trace_seq_init(&iter
->seq
);
3694 trace_access_unlock(iter
->cpu_file
);
3695 trace_event_read_unlock();
3696 mutex_unlock(&iter
->mutex
);
3700 ret
= splice_to_pipe(pipe
, &spd
);
3702 splice_shrink_spd(&spd
);
3706 mutex_unlock(&iter
->mutex
);
3710 struct ftrace_entries_info
{
3711 struct trace_array
*tr
;
3715 static int tracing_entries_open(struct inode
*inode
, struct file
*filp
)
3717 struct ftrace_entries_info
*info
;
3719 if (tracing_disabled
)
3722 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
3726 info
->tr
= &global_trace
;
3727 info
->cpu
= (unsigned long)inode
->i_private
;
3729 filp
->private_data
= info
;
3735 tracing_entries_read(struct file
*filp
, char __user
*ubuf
,
3736 size_t cnt
, loff_t
*ppos
)
3738 struct ftrace_entries_info
*info
= filp
->private_data
;
3739 struct trace_array
*tr
= info
->tr
;
3744 mutex_lock(&trace_types_lock
);
3746 if (info
->cpu
== RING_BUFFER_ALL_CPUS
) {
3747 int cpu
, buf_size_same
;
3752 /* check if all cpu sizes are same */
3753 for_each_tracing_cpu(cpu
) {
3754 /* fill in the size from first enabled cpu */
3756 size
= tr
->data
[cpu
]->entries
;
3757 if (size
!= tr
->data
[cpu
]->entries
) {
3763 if (buf_size_same
) {
3764 if (!ring_buffer_expanded
)
3765 r
= sprintf(buf
, "%lu (expanded: %lu)\n",
3767 trace_buf_size
>> 10);
3769 r
= sprintf(buf
, "%lu\n", size
>> 10);
3771 r
= sprintf(buf
, "X\n");
3773 r
= sprintf(buf
, "%lu\n", tr
->data
[info
->cpu
]->entries
>> 10);
3775 mutex_unlock(&trace_types_lock
);
3777 ret
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3782 tracing_entries_write(struct file
*filp
, const char __user
*ubuf
,
3783 size_t cnt
, loff_t
*ppos
)
3785 struct ftrace_entries_info
*info
= filp
->private_data
;
3789 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
3793 /* must have at least 1 entry */
3797 /* value is in KB */
3800 ret
= tracing_resize_ring_buffer(val
, info
->cpu
);
3810 tracing_entries_release(struct inode
*inode
, struct file
*filp
)
3812 struct ftrace_entries_info
*info
= filp
->private_data
;
3820 tracing_total_entries_read(struct file
*filp
, char __user
*ubuf
,
3821 size_t cnt
, loff_t
*ppos
)
3823 struct trace_array
*tr
= filp
->private_data
;
3826 unsigned long size
= 0, expanded_size
= 0;
3828 mutex_lock(&trace_types_lock
);
3829 for_each_tracing_cpu(cpu
) {
3830 size
+= tr
->data
[cpu
]->entries
>> 10;
3831 if (!ring_buffer_expanded
)
3832 expanded_size
+= trace_buf_size
>> 10;
3834 if (ring_buffer_expanded
)
3835 r
= sprintf(buf
, "%lu\n", size
);
3837 r
= sprintf(buf
, "%lu (expanded: %lu)\n", size
, expanded_size
);
3838 mutex_unlock(&trace_types_lock
);
3840 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3844 tracing_free_buffer_write(struct file
*filp
, const char __user
*ubuf
,
3845 size_t cnt
, loff_t
*ppos
)
3848 * There is no need to read what the user has written, this function
3849 * is just to make sure that there is no error when "echo" is used
3858 tracing_free_buffer_release(struct inode
*inode
, struct file
*filp
)
3860 /* disable tracing ? */
3861 if (trace_flags
& TRACE_ITER_STOP_ON_FREE
)
3863 /* resize the ring buffer to 0 */
3864 tracing_resize_ring_buffer(0, RING_BUFFER_ALL_CPUS
);
3870 tracing_mark_write(struct file
*filp
, const char __user
*ubuf
,
3871 size_t cnt
, loff_t
*fpos
)
3873 unsigned long addr
= (unsigned long)ubuf
;
3874 struct ring_buffer_event
*event
;
3875 struct ring_buffer
*buffer
;
3876 struct print_entry
*entry
;
3877 unsigned long irq_flags
;
3878 struct page
*pages
[2];
3888 if (tracing_disabled
)
3891 if (!(trace_flags
& TRACE_ITER_MARKERS
))
3894 if (cnt
> TRACE_BUF_SIZE
)
3895 cnt
= TRACE_BUF_SIZE
;
3898 * Userspace is injecting traces into the kernel trace buffer.
3899 * We want to be as non intrusive as possible.
3900 * To do so, we do not want to allocate any special buffers
3901 * or take any locks, but instead write the userspace data
3902 * straight into the ring buffer.
3904 * First we need to pin the userspace buffer into memory,
3905 * which, most likely it is, because it just referenced it.
3906 * But there's no guarantee that it is. By using get_user_pages_fast()
3907 * and kmap_atomic/kunmap_atomic() we can get access to the
3908 * pages directly. We then write the data directly into the
3911 BUILD_BUG_ON(TRACE_BUF_SIZE
>= PAGE_SIZE
);
3913 /* check if we cross pages */
3914 if ((addr
& PAGE_MASK
) != ((addr
+ cnt
) & PAGE_MASK
))
3917 offset
= addr
& (PAGE_SIZE
- 1);
3920 ret
= get_user_pages_fast(addr
, nr_pages
, 0, pages
);
3921 if (ret
< nr_pages
) {
3923 put_page(pages
[ret
]);
3928 for (i
= 0; i
< nr_pages
; i
++)
3929 map_page
[i
] = kmap_atomic(pages
[i
]);
3931 local_save_flags(irq_flags
);
3932 size
= sizeof(*entry
) + cnt
+ 2; /* possible \n added */
3933 buffer
= global_trace
.buffer
;
3934 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, size
,
3935 irq_flags
, preempt_count());
3937 /* Ring buffer disabled, return as if not open for write */
3942 entry
= ring_buffer_event_data(event
);
3943 entry
->ip
= _THIS_IP_
;
3945 if (nr_pages
== 2) {
3946 len
= PAGE_SIZE
- offset
;
3947 memcpy(&entry
->buf
, map_page
[0] + offset
, len
);
3948 memcpy(&entry
->buf
[len
], map_page
[1], cnt
- len
);
3950 memcpy(&entry
->buf
, map_page
[0] + offset
, cnt
);
3952 if (entry
->buf
[cnt
- 1] != '\n') {
3953 entry
->buf
[cnt
] = '\n';
3954 entry
->buf
[cnt
+ 1] = '\0';
3956 entry
->buf
[cnt
] = '\0';
3958 ring_buffer_unlock_commit(buffer
, event
);
3965 for (i
= 0; i
< nr_pages
; i
++){
3966 kunmap_atomic(map_page
[i
]);
3973 static int tracing_clock_show(struct seq_file
*m
, void *v
)
3977 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++)
3979 "%s%s%s%s", i
? " " : "",
3980 i
== trace_clock_id
? "[" : "", trace_clocks
[i
].name
,
3981 i
== trace_clock_id
? "]" : "");
3987 static ssize_t
tracing_clock_write(struct file
*filp
, const char __user
*ubuf
,
3988 size_t cnt
, loff_t
*fpos
)
3991 const char *clockstr
;
3994 if (cnt
>= sizeof(buf
))
3997 if (copy_from_user(&buf
, ubuf
, cnt
))
4002 clockstr
= strstrip(buf
);
4004 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++) {
4005 if (strcmp(trace_clocks
[i
].name
, clockstr
) == 0)
4008 if (i
== ARRAY_SIZE(trace_clocks
))
4013 mutex_lock(&trace_types_lock
);
4015 ring_buffer_set_clock(global_trace
.buffer
, trace_clocks
[i
].func
);
4017 ring_buffer_set_clock(max_tr
.buffer
, trace_clocks
[i
].func
);
4019 mutex_unlock(&trace_types_lock
);
4026 static int tracing_clock_open(struct inode
*inode
, struct file
*file
)
4028 if (tracing_disabled
)
4030 return single_open(file
, tracing_clock_show
, NULL
);
4033 static const struct file_operations tracing_max_lat_fops
= {
4034 .open
= tracing_open_generic
,
4035 .read
= tracing_max_lat_read
,
4036 .write
= tracing_max_lat_write
,
4037 .llseek
= generic_file_llseek
,
4040 static const struct file_operations tracing_ctrl_fops
= {
4041 .open
= tracing_open_generic
,
4042 .read
= tracing_ctrl_read
,
4043 .write
= tracing_ctrl_write
,
4044 .llseek
= generic_file_llseek
,
4047 static const struct file_operations set_tracer_fops
= {
4048 .open
= tracing_open_generic
,
4049 .read
= tracing_set_trace_read
,
4050 .write
= tracing_set_trace_write
,
4051 .llseek
= generic_file_llseek
,
4054 static const struct file_operations tracing_pipe_fops
= {
4055 .open
= tracing_open_pipe
,
4056 .poll
= tracing_poll_pipe
,
4057 .read
= tracing_read_pipe
,
4058 .splice_read
= tracing_splice_read_pipe
,
4059 .release
= tracing_release_pipe
,
4060 .llseek
= no_llseek
,
4063 static const struct file_operations tracing_entries_fops
= {
4064 .open
= tracing_entries_open
,
4065 .read
= tracing_entries_read
,
4066 .write
= tracing_entries_write
,
4067 .release
= tracing_entries_release
,
4068 .llseek
= generic_file_llseek
,
4071 static const struct file_operations tracing_total_entries_fops
= {
4072 .open
= tracing_open_generic
,
4073 .read
= tracing_total_entries_read
,
4074 .llseek
= generic_file_llseek
,
4077 static const struct file_operations tracing_free_buffer_fops
= {
4078 .write
= tracing_free_buffer_write
,
4079 .release
= tracing_free_buffer_release
,
4082 static const struct file_operations tracing_mark_fops
= {
4083 .open
= tracing_open_generic
,
4084 .write
= tracing_mark_write
,
4085 .llseek
= generic_file_llseek
,
4088 static const struct file_operations trace_clock_fops
= {
4089 .open
= tracing_clock_open
,
4091 .llseek
= seq_lseek
,
4092 .release
= single_release
,
4093 .write
= tracing_clock_write
,
4096 struct ftrace_buffer_info
{
4097 struct trace_array
*tr
;
4103 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
)
4105 int cpu
= (int)(long)inode
->i_private
;
4106 struct ftrace_buffer_info
*info
;
4108 if (tracing_disabled
)
4111 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
4115 info
->tr
= &global_trace
;
4118 /* Force reading ring buffer for first read */
4119 info
->read
= (unsigned int)-1;
4121 filp
->private_data
= info
;
4123 return nonseekable_open(inode
, filp
);
4127 tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
4128 size_t count
, loff_t
*ppos
)
4130 struct ftrace_buffer_info
*info
= filp
->private_data
;
4138 info
->spare
= ring_buffer_alloc_read_page(info
->tr
->buffer
, info
->cpu
);
4142 /* Do we have previous read data to read? */
4143 if (info
->read
< PAGE_SIZE
)
4146 trace_access_lock(info
->cpu
);
4147 ret
= ring_buffer_read_page(info
->tr
->buffer
,
4151 trace_access_unlock(info
->cpu
);
4158 size
= PAGE_SIZE
- info
->read
;
4162 ret
= copy_to_user(ubuf
, info
->spare
+ info
->read
, size
);
4173 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
)
4175 struct ftrace_buffer_info
*info
= file
->private_data
;
4178 ring_buffer_free_read_page(info
->tr
->buffer
, info
->spare
);
4185 struct ring_buffer
*buffer
;
4190 static void buffer_pipe_buf_release(struct pipe_inode_info
*pipe
,
4191 struct pipe_buffer
*buf
)
4193 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
4198 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
4203 static void buffer_pipe_buf_get(struct pipe_inode_info
*pipe
,
4204 struct pipe_buffer
*buf
)
4206 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
4211 /* Pipe buffer operations for a buffer. */
4212 static const struct pipe_buf_operations buffer_pipe_buf_ops
= {
4214 .map
= generic_pipe_buf_map
,
4215 .unmap
= generic_pipe_buf_unmap
,
4216 .confirm
= generic_pipe_buf_confirm
,
4217 .release
= buffer_pipe_buf_release
,
4218 .steal
= generic_pipe_buf_steal
,
4219 .get
= buffer_pipe_buf_get
,
4223 * Callback from splice_to_pipe(), if we need to release some pages
4224 * at the end of the spd in case we error'ed out in filling the pipe.
4226 static void buffer_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
4228 struct buffer_ref
*ref
=
4229 (struct buffer_ref
*)spd
->partial
[i
].private;
4234 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
4236 spd
->partial
[i
].private = 0;
4240 tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
4241 struct pipe_inode_info
*pipe
, size_t len
,
4244 struct ftrace_buffer_info
*info
= file
->private_data
;
4245 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
4246 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
4247 struct splice_pipe_desc spd
= {
4249 .partial
= partial_def
,
4250 .nr_pages_max
= PIPE_DEF_BUFFERS
,
4252 .ops
= &buffer_pipe_buf_ops
,
4253 .spd_release
= buffer_spd_release
,
4255 struct buffer_ref
*ref
;
4256 int entries
, size
, i
;
4259 if (splice_grow_spd(pipe
, &spd
))
4262 if (*ppos
& (PAGE_SIZE
- 1)) {
4263 WARN_ONCE(1, "Ftrace: previous read must page-align\n");
4268 if (len
& (PAGE_SIZE
- 1)) {
4269 WARN_ONCE(1, "Ftrace: splice_read should page-align\n");
4270 if (len
< PAGE_SIZE
) {
4277 trace_access_lock(info
->cpu
);
4278 entries
= ring_buffer_entries_cpu(info
->tr
->buffer
, info
->cpu
);
4280 for (i
= 0; i
< pipe
->buffers
&& len
&& entries
; i
++, len
-= PAGE_SIZE
) {
4284 ref
= kzalloc(sizeof(*ref
), GFP_KERNEL
);
4289 ref
->buffer
= info
->tr
->buffer
;
4290 ref
->page
= ring_buffer_alloc_read_page(ref
->buffer
, info
->cpu
);
4296 r
= ring_buffer_read_page(ref
->buffer
, &ref
->page
,
4299 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
4305 * zero out any left over data, this is going to
4308 size
= ring_buffer_page_len(ref
->page
);
4309 if (size
< PAGE_SIZE
)
4310 memset(ref
->page
+ size
, 0, PAGE_SIZE
- size
);
4312 page
= virt_to_page(ref
->page
);
4314 spd
.pages
[i
] = page
;
4315 spd
.partial
[i
].len
= PAGE_SIZE
;
4316 spd
.partial
[i
].offset
= 0;
4317 spd
.partial
[i
].private = (unsigned long)ref
;
4321 entries
= ring_buffer_entries_cpu(info
->tr
->buffer
, info
->cpu
);
4324 trace_access_unlock(info
->cpu
);
4327 /* did we read anything? */
4328 if (!spd
.nr_pages
) {
4329 if (flags
& SPLICE_F_NONBLOCK
)
4337 ret
= splice_to_pipe(pipe
, &spd
);
4338 splice_shrink_spd(&spd
);
4343 static const struct file_operations tracing_buffers_fops
= {
4344 .open
= tracing_buffers_open
,
4345 .read
= tracing_buffers_read
,
4346 .release
= tracing_buffers_release
,
4347 .splice_read
= tracing_buffers_splice_read
,
4348 .llseek
= no_llseek
,
4352 tracing_stats_read(struct file
*filp
, char __user
*ubuf
,
4353 size_t count
, loff_t
*ppos
)
4355 unsigned long cpu
= (unsigned long)filp
->private_data
;
4356 struct trace_array
*tr
= &global_trace
;
4357 struct trace_seq
*s
;
4359 unsigned long long t
;
4360 unsigned long usec_rem
;
4362 s
= kmalloc(sizeof(*s
), GFP_KERNEL
);
4368 cnt
= ring_buffer_entries_cpu(tr
->buffer
, cpu
);
4369 trace_seq_printf(s
, "entries: %ld\n", cnt
);
4371 cnt
= ring_buffer_overrun_cpu(tr
->buffer
, cpu
);
4372 trace_seq_printf(s
, "overrun: %ld\n", cnt
);
4374 cnt
= ring_buffer_commit_overrun_cpu(tr
->buffer
, cpu
);
4375 trace_seq_printf(s
, "commit overrun: %ld\n", cnt
);
4377 cnt
= ring_buffer_bytes_cpu(tr
->buffer
, cpu
);
4378 trace_seq_printf(s
, "bytes: %ld\n", cnt
);
4380 t
= ns2usecs(ring_buffer_oldest_event_ts(tr
->buffer
, cpu
));
4381 usec_rem
= do_div(t
, USEC_PER_SEC
);
4382 trace_seq_printf(s
, "oldest event ts: %5llu.%06lu\n", t
, usec_rem
);
4384 t
= ns2usecs(ring_buffer_time_stamp(tr
->buffer
, cpu
));
4385 usec_rem
= do_div(t
, USEC_PER_SEC
);
4386 trace_seq_printf(s
, "now ts: %5llu.%06lu\n", t
, usec_rem
);
4388 count
= simple_read_from_buffer(ubuf
, count
, ppos
, s
->buffer
, s
->len
);
4395 static const struct file_operations tracing_stats_fops
= {
4396 .open
= tracing_open_generic
,
4397 .read
= tracing_stats_read
,
4398 .llseek
= generic_file_llseek
,
4401 #ifdef CONFIG_DYNAMIC_FTRACE
4403 int __weak
ftrace_arch_read_dyn_info(char *buf
, int size
)
4409 tracing_read_dyn_info(struct file
*filp
, char __user
*ubuf
,
4410 size_t cnt
, loff_t
*ppos
)
4412 static char ftrace_dyn_info_buffer
[1024];
4413 static DEFINE_MUTEX(dyn_info_mutex
);
4414 unsigned long *p
= filp
->private_data
;
4415 char *buf
= ftrace_dyn_info_buffer
;
4416 int size
= ARRAY_SIZE(ftrace_dyn_info_buffer
);
4419 mutex_lock(&dyn_info_mutex
);
4420 r
= sprintf(buf
, "%ld ", *p
);
4422 r
+= ftrace_arch_read_dyn_info(buf
+r
, (size
-1)-r
);
4425 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
4427 mutex_unlock(&dyn_info_mutex
);
4432 static const struct file_operations tracing_dyn_info_fops
= {
4433 .open
= tracing_open_generic
,
4434 .read
= tracing_read_dyn_info
,
4435 .llseek
= generic_file_llseek
,
4439 static struct dentry
*d_tracer
;
4441 struct dentry
*tracing_init_dentry(void)
4448 if (!debugfs_initialized())
4451 d_tracer
= debugfs_create_dir("tracing", NULL
);
4453 if (!d_tracer
&& !once
) {
4455 pr_warning("Could not create debugfs directory 'tracing'\n");
4462 static struct dentry
*d_percpu
;
4464 struct dentry
*tracing_dentry_percpu(void)
4467 struct dentry
*d_tracer
;
4472 d_tracer
= tracing_init_dentry();
4477 d_percpu
= debugfs_create_dir("per_cpu", d_tracer
);
4479 if (!d_percpu
&& !once
) {
4481 pr_warning("Could not create debugfs directory 'per_cpu'\n");
4488 static void tracing_init_debugfs_percpu(long cpu
)
4490 struct dentry
*d_percpu
= tracing_dentry_percpu();
4491 struct dentry
*d_cpu
;
4492 char cpu_dir
[30]; /* 30 characters should be more than enough */
4497 snprintf(cpu_dir
, 30, "cpu%ld", cpu
);
4498 d_cpu
= debugfs_create_dir(cpu_dir
, d_percpu
);
4500 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir
);
4504 /* per cpu trace_pipe */
4505 trace_create_file("trace_pipe", 0444, d_cpu
,
4506 (void *) cpu
, &tracing_pipe_fops
);
4509 trace_create_file("trace", 0644, d_cpu
,
4510 (void *) cpu
, &tracing_fops
);
4512 trace_create_file("trace_pipe_raw", 0444, d_cpu
,
4513 (void *) cpu
, &tracing_buffers_fops
);
4515 trace_create_file("stats", 0444, d_cpu
,
4516 (void *) cpu
, &tracing_stats_fops
);
4518 trace_create_file("buffer_size_kb", 0444, d_cpu
,
4519 (void *) cpu
, &tracing_entries_fops
);
4522 #ifdef CONFIG_FTRACE_SELFTEST
4523 /* Let selftest have access to static functions in this file */
4524 #include "trace_selftest.c"
4527 struct trace_option_dentry
{
4528 struct tracer_opt
*opt
;
4529 struct tracer_flags
*flags
;
4530 struct dentry
*entry
;
4534 trace_options_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
4537 struct trace_option_dentry
*topt
= filp
->private_data
;
4540 if (topt
->flags
->val
& topt
->opt
->bit
)
4545 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
4549 trace_options_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
4552 struct trace_option_dentry
*topt
= filp
->private_data
;
4556 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
4560 if (val
!= 0 && val
!= 1)
4563 if (!!(topt
->flags
->val
& topt
->opt
->bit
) != val
) {
4564 mutex_lock(&trace_types_lock
);
4565 ret
= __set_tracer_option(current_trace
, topt
->flags
,
4567 mutex_unlock(&trace_types_lock
);
4578 static const struct file_operations trace_options_fops
= {
4579 .open
= tracing_open_generic
,
4580 .read
= trace_options_read
,
4581 .write
= trace_options_write
,
4582 .llseek
= generic_file_llseek
,
4586 trace_options_core_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
4589 long index
= (long)filp
->private_data
;
4592 if (trace_flags
& (1 << index
))
4597 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
4601 trace_options_core_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
4604 long index
= (long)filp
->private_data
;
4608 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
4612 if (val
!= 0 && val
!= 1)
4614 set_tracer_flags(1 << index
, val
);
4621 static const struct file_operations trace_options_core_fops
= {
4622 .open
= tracing_open_generic
,
4623 .read
= trace_options_core_read
,
4624 .write
= trace_options_core_write
,
4625 .llseek
= generic_file_llseek
,
4628 struct dentry
*trace_create_file(const char *name
,
4630 struct dentry
*parent
,
4632 const struct file_operations
*fops
)
4636 ret
= debugfs_create_file(name
, mode
, parent
, data
, fops
);
4638 pr_warning("Could not create debugfs '%s' entry\n", name
);
4644 static struct dentry
*trace_options_init_dentry(void)
4646 struct dentry
*d_tracer
;
4647 static struct dentry
*t_options
;
4652 d_tracer
= tracing_init_dentry();
4656 t_options
= debugfs_create_dir("options", d_tracer
);
4658 pr_warning("Could not create debugfs directory 'options'\n");
4666 create_trace_option_file(struct trace_option_dentry
*topt
,
4667 struct tracer_flags
*flags
,
4668 struct tracer_opt
*opt
)
4670 struct dentry
*t_options
;
4672 t_options
= trace_options_init_dentry();
4676 topt
->flags
= flags
;
4679 topt
->entry
= trace_create_file(opt
->name
, 0644, t_options
, topt
,
4680 &trace_options_fops
);
4684 static struct trace_option_dentry
*
4685 create_trace_option_files(struct tracer
*tracer
)
4687 struct trace_option_dentry
*topts
;
4688 struct tracer_flags
*flags
;
4689 struct tracer_opt
*opts
;
4695 flags
= tracer
->flags
;
4697 if (!flags
|| !flags
->opts
)
4702 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
4705 topts
= kcalloc(cnt
+ 1, sizeof(*topts
), GFP_KERNEL
);
4709 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
4710 create_trace_option_file(&topts
[cnt
], flags
,
4717 destroy_trace_option_files(struct trace_option_dentry
*topts
)
4724 for (cnt
= 0; topts
[cnt
].opt
; cnt
++) {
4725 if (topts
[cnt
].entry
)
4726 debugfs_remove(topts
[cnt
].entry
);
4732 static struct dentry
*
4733 create_trace_option_core_file(const char *option
, long index
)
4735 struct dentry
*t_options
;
4737 t_options
= trace_options_init_dentry();
4741 return trace_create_file(option
, 0644, t_options
, (void *)index
,
4742 &trace_options_core_fops
);
4745 static __init
void create_trace_options_dir(void)
4747 struct dentry
*t_options
;
4750 t_options
= trace_options_init_dentry();
4754 for (i
= 0; trace_options
[i
]; i
++)
4755 create_trace_option_core_file(trace_options
[i
], i
);
4759 rb_simple_read(struct file
*filp
, char __user
*ubuf
,
4760 size_t cnt
, loff_t
*ppos
)
4762 struct trace_array
*tr
= filp
->private_data
;
4763 struct ring_buffer
*buffer
= tr
->buffer
;
4768 r
= ring_buffer_record_is_on(buffer
);
4772 r
= sprintf(buf
, "%d\n", r
);
4774 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
4778 rb_simple_write(struct file
*filp
, const char __user
*ubuf
,
4779 size_t cnt
, loff_t
*ppos
)
4781 struct trace_array
*tr
= filp
->private_data
;
4782 struct ring_buffer
*buffer
= tr
->buffer
;
4786 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
4792 ring_buffer_record_on(buffer
);
4794 ring_buffer_record_off(buffer
);
4802 static const struct file_operations rb_simple_fops
= {
4803 .open
= tracing_open_generic
,
4804 .read
= rb_simple_read
,
4805 .write
= rb_simple_write
,
4806 .llseek
= default_llseek
,
4809 static __init
int tracer_init_debugfs(void)
4811 struct dentry
*d_tracer
;
4814 trace_access_lock_init();
4816 d_tracer
= tracing_init_dentry();
4818 trace_create_file("tracing_enabled", 0644, d_tracer
,
4819 &global_trace
, &tracing_ctrl_fops
);
4821 trace_create_file("trace_options", 0644, d_tracer
,
4822 NULL
, &tracing_iter_fops
);
4824 trace_create_file("tracing_cpumask", 0644, d_tracer
,
4825 NULL
, &tracing_cpumask_fops
);
4827 trace_create_file("trace", 0644, d_tracer
,
4828 (void *) TRACE_PIPE_ALL_CPU
, &tracing_fops
);
4830 trace_create_file("available_tracers", 0444, d_tracer
,
4831 &global_trace
, &show_traces_fops
);
4833 trace_create_file("current_tracer", 0644, d_tracer
,
4834 &global_trace
, &set_tracer_fops
);
4836 #ifdef CONFIG_TRACER_MAX_TRACE
4837 trace_create_file("tracing_max_latency", 0644, d_tracer
,
4838 &tracing_max_latency
, &tracing_max_lat_fops
);
4841 trace_create_file("tracing_thresh", 0644, d_tracer
,
4842 &tracing_thresh
, &tracing_max_lat_fops
);
4844 trace_create_file("README", 0444, d_tracer
,
4845 NULL
, &tracing_readme_fops
);
4847 trace_create_file("trace_pipe", 0444, d_tracer
,
4848 (void *) TRACE_PIPE_ALL_CPU
, &tracing_pipe_fops
);
4850 trace_create_file("buffer_size_kb", 0644, d_tracer
,
4851 (void *) RING_BUFFER_ALL_CPUS
, &tracing_entries_fops
);
4853 trace_create_file("buffer_total_size_kb", 0444, d_tracer
,
4854 &global_trace
, &tracing_total_entries_fops
);
4856 trace_create_file("free_buffer", 0644, d_tracer
,
4857 &global_trace
, &tracing_free_buffer_fops
);
4859 trace_create_file("trace_marker", 0220, d_tracer
,
4860 NULL
, &tracing_mark_fops
);
4862 trace_create_file("saved_cmdlines", 0444, d_tracer
,
4863 NULL
, &tracing_saved_cmdlines_fops
);
4865 trace_create_file("trace_clock", 0644, d_tracer
, NULL
,
4868 trace_create_file("tracing_on", 0644, d_tracer
,
4869 &global_trace
, &rb_simple_fops
);
4871 #ifdef CONFIG_DYNAMIC_FTRACE
4872 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
4873 &ftrace_update_tot_cnt
, &tracing_dyn_info_fops
);
4876 create_trace_options_dir();
4878 for_each_tracing_cpu(cpu
)
4879 tracing_init_debugfs_percpu(cpu
);
4884 static int trace_panic_handler(struct notifier_block
*this,
4885 unsigned long event
, void *unused
)
4887 if (ftrace_dump_on_oops
)
4888 ftrace_dump(ftrace_dump_on_oops
);
4892 static struct notifier_block trace_panic_notifier
= {
4893 .notifier_call
= trace_panic_handler
,
4895 .priority
= 150 /* priority: INT_MAX >= x >= 0 */
4898 static int trace_die_handler(struct notifier_block
*self
,
4904 if (ftrace_dump_on_oops
)
4905 ftrace_dump(ftrace_dump_on_oops
);
4913 static struct notifier_block trace_die_notifier
= {
4914 .notifier_call
= trace_die_handler
,
4919 * printk is set to max of 1024, we really don't need it that big.
4920 * Nothing should be printing 1000 characters anyway.
4922 #define TRACE_MAX_PRINT 1000
4925 * Define here KERN_TRACE so that we have one place to modify
4926 * it if we decide to change what log level the ftrace dump
4929 #define KERN_TRACE KERN_EMERG
4932 trace_printk_seq(struct trace_seq
*s
)
4934 /* Probably should print a warning here. */
4938 /* should be zero ended, but we are paranoid. */
4939 s
->buffer
[s
->len
] = 0;
4941 printk(KERN_TRACE
"%s", s
->buffer
);
4946 void trace_init_global_iter(struct trace_iterator
*iter
)
4948 iter
->tr
= &global_trace
;
4949 iter
->trace
= current_trace
;
4950 iter
->cpu_file
= TRACE_PIPE_ALL_CPU
;
4954 __ftrace_dump(bool disable_tracing
, enum ftrace_dump_mode oops_dump_mode
)
4956 static arch_spinlock_t ftrace_dump_lock
=
4957 (arch_spinlock_t
)__ARCH_SPIN_LOCK_UNLOCKED
;
4958 /* use static because iter can be a bit big for the stack */
4959 static struct trace_iterator iter
;
4960 unsigned int old_userobj
;
4961 static int dump_ran
;
4962 unsigned long flags
;
4966 local_irq_save(flags
);
4967 arch_spin_lock(&ftrace_dump_lock
);
4975 /* Did function tracer already get disabled? */
4976 if (ftrace_is_dead()) {
4977 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
4978 printk("# MAY BE MISSING FUNCTION EVENTS\n");
4981 if (disable_tracing
)
4984 trace_init_global_iter(&iter
);
4986 for_each_tracing_cpu(cpu
) {
4987 atomic_inc(&iter
.tr
->data
[cpu
]->disabled
);
4990 old_userobj
= trace_flags
& TRACE_ITER_SYM_USEROBJ
;
4992 /* don't look at user memory in panic mode */
4993 trace_flags
&= ~TRACE_ITER_SYM_USEROBJ
;
4995 /* Simulate the iterator */
4996 iter
.tr
= &global_trace
;
4997 iter
.trace
= current_trace
;
4999 switch (oops_dump_mode
) {
5001 iter
.cpu_file
= TRACE_PIPE_ALL_CPU
;
5004 iter
.cpu_file
= raw_smp_processor_id();
5009 printk(KERN_TRACE
"Bad dumping mode, switching to all CPUs dump\n");
5010 iter
.cpu_file
= TRACE_PIPE_ALL_CPU
;
5013 printk(KERN_TRACE
"Dumping ftrace buffer:\n");
5016 * We need to stop all tracing on all CPUS to read the
5017 * the next buffer. This is a bit expensive, but is
5018 * not done often. We fill all what we can read,
5019 * and then release the locks again.
5022 while (!trace_empty(&iter
)) {
5025 printk(KERN_TRACE
"---------------------------------\n");
5029 /* reset all but tr, trace, and overruns */
5030 memset(&iter
.seq
, 0,
5031 sizeof(struct trace_iterator
) -
5032 offsetof(struct trace_iterator
, seq
));
5033 iter
.iter_flags
|= TRACE_FILE_LAT_FMT
;
5036 if (trace_find_next_entry_inc(&iter
) != NULL
) {
5039 ret
= print_trace_line(&iter
);
5040 if (ret
!= TRACE_TYPE_NO_CONSUME
)
5041 trace_consume(&iter
);
5043 touch_nmi_watchdog();
5045 trace_printk_seq(&iter
.seq
);
5049 printk(KERN_TRACE
" (ftrace buffer empty)\n");
5051 printk(KERN_TRACE
"---------------------------------\n");
5054 /* Re-enable tracing if requested */
5055 if (!disable_tracing
) {
5056 trace_flags
|= old_userobj
;
5058 for_each_tracing_cpu(cpu
) {
5059 atomic_dec(&iter
.tr
->data
[cpu
]->disabled
);
5065 arch_spin_unlock(&ftrace_dump_lock
);
5066 local_irq_restore(flags
);
5069 /* By default: disable tracing after the dump */
5070 void ftrace_dump(enum ftrace_dump_mode oops_dump_mode
)
5072 __ftrace_dump(true, oops_dump_mode
);
5074 EXPORT_SYMBOL_GPL(ftrace_dump
);
5076 __init
static int tracer_alloc_buffers(void)
5079 enum ring_buffer_flags rb_flags
;
5084 if (!alloc_cpumask_var(&tracing_buffer_mask
, GFP_KERNEL
))
5087 if (!alloc_cpumask_var(&tracing_cpumask
, GFP_KERNEL
))
5088 goto out_free_buffer_mask
;
5090 /* Only allocate trace_printk buffers if a trace_printk exists */
5091 if (__stop___trace_bprintk_fmt
!= __start___trace_bprintk_fmt
)
5092 trace_printk_init_buffers();
5094 /* To save memory, keep the ring buffer size to its minimum */
5095 if (ring_buffer_expanded
)
5096 ring_buf_size
= trace_buf_size
;
5100 rb_flags
= trace_flags
& TRACE_ITER_OVERWRITE
? RB_FL_OVERWRITE
: 0;
5102 cpumask_copy(tracing_buffer_mask
, cpu_possible_mask
);
5103 cpumask_copy(tracing_cpumask
, cpu_all_mask
);
5105 /* TODO: make the number of buffers hot pluggable with CPUS */
5106 global_trace
.buffer
= ring_buffer_alloc(ring_buf_size
, rb_flags
);
5107 if (!global_trace
.buffer
) {
5108 printk(KERN_ERR
"tracer: failed to allocate ring buffer!\n");
5110 goto out_free_cpumask
;
5112 if (global_trace
.buffer_disabled
)
5116 #ifdef CONFIG_TRACER_MAX_TRACE
5117 max_tr
.buffer
= ring_buffer_alloc(1, rb_flags
);
5118 if (!max_tr
.buffer
) {
5119 printk(KERN_ERR
"tracer: failed to allocate max ring buffer!\n");
5121 ring_buffer_free(global_trace
.buffer
);
5122 goto out_free_cpumask
;
5126 /* Allocate the first page for all buffers */
5127 for_each_tracing_cpu(i
) {
5128 global_trace
.data
[i
] = &per_cpu(global_trace_cpu
, i
);
5129 max_tr
.data
[i
] = &per_cpu(max_tr_data
, i
);
5132 set_buffer_entries(&global_trace
,
5133 ring_buffer_size(global_trace
.buffer
, 0));
5134 #ifdef CONFIG_TRACER_MAX_TRACE
5135 set_buffer_entries(&max_tr
, 1);
5138 trace_init_cmdlines();
5140 register_tracer(&nop_trace
);
5141 current_trace
= &nop_trace
;
5142 /* All seems OK, enable tracing */
5143 tracing_disabled
= 0;
5145 atomic_notifier_chain_register(&panic_notifier_list
,
5146 &trace_panic_notifier
);
5148 register_die_notifier(&trace_die_notifier
);
5153 free_cpumask_var(tracing_cpumask
);
5154 out_free_buffer_mask
:
5155 free_cpumask_var(tracing_buffer_mask
);
5160 __init
static int clear_boot_tracer(void)
5163 * The default tracer at boot buffer is an init section.
5164 * This function is called in lateinit. If we did not
5165 * find the boot tracer, then clear it out, to prevent
5166 * later registration from accessing the buffer that is
5167 * about to be freed.
5169 if (!default_bootup_tracer
)
5172 printk(KERN_INFO
"ftrace bootup tracer '%s' not registered.\n",
5173 default_bootup_tracer
);
5174 default_bootup_tracer
= NULL
;
5179 early_initcall(tracer_alloc_buffers
);
5180 fs_initcall(tracer_init_debugfs
);
5181 late_initcall(clear_boot_tracer
);