2 * ring buffer based function tracer
4 * Copyright (C) 2007-2012 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 Nadia Yvette Chambers
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>
41 #include <linux/sched/rt.h>
44 #include "trace_output.h"
47 * On boot up, the ring buffer is set to the minimum size, so that
48 * we do not waste memory on systems that are not using tracing.
50 bool ring_buffer_expanded
;
53 * We need to change this state when a selftest is running.
54 * A selftest will lurk into the ring-buffer to count the
55 * entries inserted during the selftest although some concurrent
56 * insertions into the ring-buffer such as trace_printk could occurred
57 * at the same time, giving false positive or negative results.
59 static bool __read_mostly tracing_selftest_running
;
62 * If a tracer is running, we do not want to run SELFTEST.
64 bool __read_mostly tracing_selftest_disabled
;
66 /* For tracers that don't implement custom flags */
67 static struct tracer_opt dummy_tracer_opt
[] = {
71 static struct tracer_flags dummy_tracer_flags
= {
73 .opts
= dummy_tracer_opt
76 static int dummy_set_flag(u32 old_flags
, u32 bit
, int set
)
82 * To prevent the comm cache from being overwritten when no
83 * tracing is active, only save the comm when a trace event
86 static DEFINE_PER_CPU(bool, trace_cmdline_save
);
89 * Kill all tracing for good (never come back).
90 * It is initialized to 1 but will turn to zero if the initialization
91 * of the tracer is successful. But that is the only place that sets
94 static int tracing_disabled
= 1;
96 DEFINE_PER_CPU(int, ftrace_cpu_disabled
);
98 cpumask_var_t __read_mostly tracing_buffer_mask
;
101 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
103 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
104 * is set, then ftrace_dump is called. This will output the contents
105 * of the ftrace buffers to the console. This is very useful for
106 * capturing traces that lead to crashes and outputing it to a
109 * It is default off, but you can enable it with either specifying
110 * "ftrace_dump_on_oops" in the kernel command line, or setting
111 * /proc/sys/kernel/ftrace_dump_on_oops
112 * Set 1 if you want to dump buffers of all CPUs
113 * Set 2 if you want to dump the buffer of the CPU that triggered oops
116 enum ftrace_dump_mode ftrace_dump_on_oops
;
118 static int tracing_set_tracer(const char *buf
);
120 #define MAX_TRACER_SIZE 100
121 static char bootup_tracer_buf
[MAX_TRACER_SIZE
] __initdata
;
122 static char *default_bootup_tracer
;
124 static bool allocate_snapshot
;
126 static int __init
set_cmdline_ftrace(char *str
)
128 strncpy(bootup_tracer_buf
, str
, MAX_TRACER_SIZE
);
129 default_bootup_tracer
= bootup_tracer_buf
;
130 /* We are using ftrace early, expand it */
131 ring_buffer_expanded
= true;
134 __setup("ftrace=", set_cmdline_ftrace
);
136 static int __init
set_ftrace_dump_on_oops(char *str
)
138 if (*str
++ != '=' || !*str
) {
139 ftrace_dump_on_oops
= DUMP_ALL
;
143 if (!strcmp("orig_cpu", str
)) {
144 ftrace_dump_on_oops
= DUMP_ORIG
;
150 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops
);
152 static int __init
boot_alloc_snapshot(char *str
)
154 allocate_snapshot
= true;
155 /* We also need the main ring buffer expanded */
156 ring_buffer_expanded
= true;
159 __setup("alloc_snapshot", boot_alloc_snapshot
);
162 static char trace_boot_options_buf
[MAX_TRACER_SIZE
] __initdata
;
163 static char *trace_boot_options __initdata
;
165 static int __init
set_trace_boot_options(char *str
)
167 strncpy(trace_boot_options_buf
, str
, MAX_TRACER_SIZE
);
168 trace_boot_options
= trace_boot_options_buf
;
171 __setup("trace_options=", set_trace_boot_options
);
173 unsigned long long ns2usecs(cycle_t nsec
)
181 * The global_trace is the descriptor that holds the tracing
182 * buffers for the live tracing. For each CPU, it contains
183 * a link list of pages that will store trace entries. The
184 * page descriptor of the pages in the memory is used to hold
185 * the link list by linking the lru item in the page descriptor
186 * to each of the pages in the buffer per CPU.
188 * For each active CPU there is a data field that holds the
189 * pages for the buffer for that CPU. Each CPU has the same number
190 * of pages allocated for its buffer.
192 static struct trace_array global_trace
;
194 LIST_HEAD(ftrace_trace_arrays
);
196 int filter_current_check_discard(struct ring_buffer
*buffer
,
197 struct ftrace_event_call
*call
, void *rec
,
198 struct ring_buffer_event
*event
)
200 return filter_check_discard(call
, rec
, buffer
, event
);
202 EXPORT_SYMBOL_GPL(filter_current_check_discard
);
204 cycle_t
ftrace_now(int cpu
)
208 /* Early boot up does not have a buffer yet */
209 if (!global_trace
.trace_buffer
.buffer
)
210 return trace_clock_local();
212 ts
= ring_buffer_time_stamp(global_trace
.trace_buffer
.buffer
, cpu
);
213 ring_buffer_normalize_time_stamp(global_trace
.trace_buffer
.buffer
, cpu
, &ts
);
218 int tracing_is_enabled(void)
220 return tracing_is_on();
224 * trace_buf_size is the size in bytes that is allocated
225 * for a buffer. Note, the number of bytes is always rounded
228 * This number is purposely set to a low number of 16384.
229 * If the dump on oops happens, it will be much appreciated
230 * to not have to wait for all that output. Anyway this can be
231 * boot time and run time configurable.
233 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
235 static unsigned long trace_buf_size
= TRACE_BUF_SIZE_DEFAULT
;
237 /* trace_types holds a link list of available tracers. */
238 static struct tracer
*trace_types __read_mostly
;
241 * trace_types_lock is used to protect the trace_types list.
243 static DEFINE_MUTEX(trace_types_lock
);
246 * serialize the access of the ring buffer
248 * ring buffer serializes readers, but it is low level protection.
249 * The validity of the events (which returns by ring_buffer_peek() ..etc)
250 * are not protected by ring buffer.
252 * The content of events may become garbage if we allow other process consumes
253 * these events concurrently:
254 * A) the page of the consumed events may become a normal page
255 * (not reader page) in ring buffer, and this page will be rewrited
256 * by events producer.
257 * B) The page of the consumed events may become a page for splice_read,
258 * and this page will be returned to system.
260 * These primitives allow multi process access to different cpu ring buffer
263 * These primitives don't distinguish read-only and read-consume access.
264 * Multi read-only access are also serialized.
268 static DECLARE_RWSEM(all_cpu_access_lock
);
269 static DEFINE_PER_CPU(struct mutex
, cpu_access_lock
);
271 static inline void trace_access_lock(int cpu
)
273 if (cpu
== RING_BUFFER_ALL_CPUS
) {
274 /* gain it for accessing the whole ring buffer. */
275 down_write(&all_cpu_access_lock
);
277 /* gain it for accessing a cpu ring buffer. */
279 /* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
280 down_read(&all_cpu_access_lock
);
282 /* Secondly block other access to this @cpu ring buffer. */
283 mutex_lock(&per_cpu(cpu_access_lock
, cpu
));
287 static inline void trace_access_unlock(int cpu
)
289 if (cpu
== RING_BUFFER_ALL_CPUS
) {
290 up_write(&all_cpu_access_lock
);
292 mutex_unlock(&per_cpu(cpu_access_lock
, cpu
));
293 up_read(&all_cpu_access_lock
);
297 static inline void trace_access_lock_init(void)
301 for_each_possible_cpu(cpu
)
302 mutex_init(&per_cpu(cpu_access_lock
, cpu
));
307 static DEFINE_MUTEX(access_lock
);
309 static inline void trace_access_lock(int cpu
)
312 mutex_lock(&access_lock
);
315 static inline void trace_access_unlock(int cpu
)
318 mutex_unlock(&access_lock
);
321 static inline void trace_access_lock_init(void)
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
| TRACE_ITER_FUNCTION
;
334 * tracing_on - enable tracing buffers
336 * This function enables tracing buffers that may have been
337 * disabled with tracing_off.
339 void tracing_on(void)
341 if (global_trace
.trace_buffer
.buffer
)
342 ring_buffer_record_on(global_trace
.trace_buffer
.buffer
);
344 * This flag is only looked at when buffers haven't been
345 * allocated yet. We don't really care about the race
346 * between setting this flag and actually turning
349 global_trace
.buffer_disabled
= 0;
351 EXPORT_SYMBOL_GPL(tracing_on
);
354 * __trace_puts - write a constant string into the trace buffer.
355 * @ip: The address of the caller
356 * @str: The constant string to write
357 * @size: The size of the string.
359 int __trace_puts(unsigned long ip
, const char *str
, int size
)
361 struct ring_buffer_event
*event
;
362 struct ring_buffer
*buffer
;
363 struct print_entry
*entry
;
364 unsigned long irq_flags
;
367 alloc
= sizeof(*entry
) + size
+ 2; /* possible \n added */
369 local_save_flags(irq_flags
);
370 buffer
= global_trace
.trace_buffer
.buffer
;
371 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, alloc
,
372 irq_flags
, preempt_count());
376 entry
= ring_buffer_event_data(event
);
379 memcpy(&entry
->buf
, str
, size
);
381 /* Add a newline if necessary */
382 if (entry
->buf
[size
- 1] != '\n') {
383 entry
->buf
[size
] = '\n';
384 entry
->buf
[size
+ 1] = '\0';
386 entry
->buf
[size
] = '\0';
388 __buffer_unlock_commit(buffer
, event
);
392 EXPORT_SYMBOL_GPL(__trace_puts
);
395 * __trace_bputs - write the pointer to a constant string into trace buffer
396 * @ip: The address of the caller
397 * @str: The constant string to write to the buffer to
399 int __trace_bputs(unsigned long ip
, const char *str
)
401 struct ring_buffer_event
*event
;
402 struct ring_buffer
*buffer
;
403 struct bputs_entry
*entry
;
404 unsigned long irq_flags
;
405 int size
= sizeof(struct bputs_entry
);
407 local_save_flags(irq_flags
);
408 buffer
= global_trace
.trace_buffer
.buffer
;
409 event
= trace_buffer_lock_reserve(buffer
, TRACE_BPUTS
, size
,
410 irq_flags
, preempt_count());
414 entry
= ring_buffer_event_data(event
);
418 __buffer_unlock_commit(buffer
, event
);
422 EXPORT_SYMBOL_GPL(__trace_bputs
);
424 #ifdef CONFIG_TRACER_SNAPSHOT
426 * trace_snapshot - take a snapshot of the current buffer.
428 * This causes a swap between the snapshot buffer and the current live
429 * tracing buffer. You can use this to take snapshots of the live
430 * trace when some condition is triggered, but continue to trace.
432 * Note, make sure to allocate the snapshot with either
433 * a tracing_snapshot_alloc(), or by doing it manually
434 * with: echo 1 > /sys/kernel/debug/tracing/snapshot
436 * If the snapshot buffer is not allocated, it will stop tracing.
437 * Basically making a permanent snapshot.
439 void tracing_snapshot(void)
441 struct trace_array
*tr
= &global_trace
;
442 struct tracer
*tracer
= tr
->current_trace
;
446 internal_trace_puts("*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
447 internal_trace_puts("*** snapshot is being ignored ***\n");
451 if (!tr
->allocated_snapshot
) {
452 internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n");
453 internal_trace_puts("*** stopping trace here! ***\n");
458 /* Note, snapshot can not be used when the tracer uses it */
459 if (tracer
->use_max_tr
) {
460 internal_trace_puts("*** LATENCY TRACER ACTIVE ***\n");
461 internal_trace_puts("*** Can not use snapshot (sorry) ***\n");
465 local_irq_save(flags
);
466 update_max_tr(tr
, current
, smp_processor_id());
467 local_irq_restore(flags
);
469 EXPORT_SYMBOL_GPL(tracing_snapshot
);
471 static int resize_buffer_duplicate_size(struct trace_buffer
*trace_buf
,
472 struct trace_buffer
*size_buf
, int cpu_id
);
473 static void set_buffer_entries(struct trace_buffer
*buf
, unsigned long val
);
475 static int alloc_snapshot(struct trace_array
*tr
)
479 if (!tr
->allocated_snapshot
) {
481 /* allocate spare buffer */
482 ret
= resize_buffer_duplicate_size(&tr
->max_buffer
,
483 &tr
->trace_buffer
, RING_BUFFER_ALL_CPUS
);
487 tr
->allocated_snapshot
= true;
493 void free_snapshot(struct trace_array
*tr
)
496 * We don't free the ring buffer. instead, resize it because
497 * The max_tr ring buffer has some state (e.g. ring->clock) and
498 * we want preserve it.
500 ring_buffer_resize(tr
->max_buffer
.buffer
, 1, RING_BUFFER_ALL_CPUS
);
501 set_buffer_entries(&tr
->max_buffer
, 1);
502 tracing_reset_online_cpus(&tr
->max_buffer
);
503 tr
->allocated_snapshot
= false;
507 * trace_snapshot_alloc - allocate and take a snapshot of the current buffer.
509 * This is similar to trace_snapshot(), but it will allocate the
510 * snapshot buffer if it isn't already allocated. Use this only
511 * where it is safe to sleep, as the allocation may sleep.
513 * This causes a swap between the snapshot buffer and the current live
514 * tracing buffer. You can use this to take snapshots of the live
515 * trace when some condition is triggered, but continue to trace.
517 void tracing_snapshot_alloc(void)
519 struct trace_array
*tr
= &global_trace
;
522 ret
= alloc_snapshot(tr
);
523 if (WARN_ON(ret
< 0))
528 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc
);
530 void tracing_snapshot(void)
532 WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
534 EXPORT_SYMBOL_GPL(tracing_snapshot
);
535 void tracing_snapshot_alloc(void)
540 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc
);
541 #endif /* CONFIG_TRACER_SNAPSHOT */
544 * tracing_off - turn off tracing buffers
546 * This function stops the tracing buffers from recording data.
547 * It does not disable any overhead the tracers themselves may
548 * be causing. This function simply causes all recording to
549 * the ring buffers to fail.
551 void tracing_off(void)
553 if (global_trace
.trace_buffer
.buffer
)
554 ring_buffer_record_off(global_trace
.trace_buffer
.buffer
);
556 * This flag is only looked at when buffers haven't been
557 * allocated yet. We don't really care about the race
558 * between setting this flag and actually turning
561 global_trace
.buffer_disabled
= 1;
563 EXPORT_SYMBOL_GPL(tracing_off
);
566 * tracing_is_on - show state of ring buffers enabled
568 int tracing_is_on(void)
570 if (global_trace
.trace_buffer
.buffer
)
571 return ring_buffer_record_is_on(global_trace
.trace_buffer
.buffer
);
572 return !global_trace
.buffer_disabled
;
574 EXPORT_SYMBOL_GPL(tracing_is_on
);
576 static int __init
set_buf_size(char *str
)
578 unsigned long buf_size
;
582 buf_size
= memparse(str
, &str
);
583 /* nr_entries can not be zero */
586 trace_buf_size
= buf_size
;
589 __setup("trace_buf_size=", set_buf_size
);
591 static int __init
set_tracing_thresh(char *str
)
593 unsigned long threshold
;
598 ret
= kstrtoul(str
, 0, &threshold
);
601 tracing_thresh
= threshold
* 1000;
604 __setup("tracing_thresh=", set_tracing_thresh
);
606 unsigned long nsecs_to_usecs(unsigned long nsecs
)
611 /* These must match the bit postions in trace_iterator_flags */
612 static const char *trace_options
[] = {
645 int in_ns
; /* is this clock in nanoseconds? */
647 { trace_clock_local
, "local", 1 },
648 { trace_clock_global
, "global", 1 },
649 { trace_clock_counter
, "counter", 0 },
656 * trace_parser_get_init - gets the buffer for trace parser
658 int trace_parser_get_init(struct trace_parser
*parser
, int size
)
660 memset(parser
, 0, sizeof(*parser
));
662 parser
->buffer
= kmalloc(size
, GFP_KERNEL
);
671 * trace_parser_put - frees the buffer for trace parser
673 void trace_parser_put(struct trace_parser
*parser
)
675 kfree(parser
->buffer
);
679 * trace_get_user - reads the user input string separated by space
680 * (matched by isspace(ch))
682 * For each string found the 'struct trace_parser' is updated,
683 * and the function returns.
685 * Returns number of bytes read.
687 * See kernel/trace/trace.h for 'struct trace_parser' details.
689 int trace_get_user(struct trace_parser
*parser
, const char __user
*ubuf
,
690 size_t cnt
, loff_t
*ppos
)
697 trace_parser_clear(parser
);
699 ret
= get_user(ch
, ubuf
++);
707 * The parser is not finished with the last write,
708 * continue reading the user input without skipping spaces.
711 /* skip white space */
712 while (cnt
&& isspace(ch
)) {
713 ret
= get_user(ch
, ubuf
++);
720 /* only spaces were written */
730 /* read the non-space input */
731 while (cnt
&& !isspace(ch
)) {
732 if (parser
->idx
< parser
->size
- 1)
733 parser
->buffer
[parser
->idx
++] = ch
;
738 ret
= get_user(ch
, ubuf
++);
745 /* We either got finished input or we have to wait for another call. */
747 parser
->buffer
[parser
->idx
] = 0;
748 parser
->cont
= false;
751 parser
->buffer
[parser
->idx
++] = ch
;
761 ssize_t
trace_seq_to_user(struct trace_seq
*s
, char __user
*ubuf
, size_t cnt
)
769 if (s
->len
<= s
->readpos
)
772 len
= s
->len
- s
->readpos
;
775 ret
= copy_to_user(ubuf
, s
->buffer
+ s
->readpos
, cnt
);
785 static ssize_t
trace_seq_to_buffer(struct trace_seq
*s
, void *buf
, size_t cnt
)
789 if (s
->len
<= s
->readpos
)
792 len
= s
->len
- s
->readpos
;
795 memcpy(buf
, s
->buffer
+ s
->readpos
, cnt
);
802 * ftrace_max_lock is used to protect the swapping of buffers
803 * when taking a max snapshot. The buffers themselves are
804 * protected by per_cpu spinlocks. But the action of the swap
805 * needs its own lock.
807 * This is defined as a arch_spinlock_t in order to help
808 * with performance when lockdep debugging is enabled.
810 * It is also used in other places outside the update_max_tr
811 * so it needs to be defined outside of the
812 * CONFIG_TRACER_MAX_TRACE.
814 static arch_spinlock_t ftrace_max_lock
=
815 (arch_spinlock_t
)__ARCH_SPIN_LOCK_UNLOCKED
;
817 unsigned long __read_mostly tracing_thresh
;
819 #ifdef CONFIG_TRACER_MAX_TRACE
820 unsigned long __read_mostly tracing_max_latency
;
823 * Copy the new maximum trace into the separate maximum-trace
824 * structure. (this way the maximum trace is permanently saved,
825 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
828 __update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
830 struct trace_buffer
*trace_buf
= &tr
->trace_buffer
;
831 struct trace_buffer
*max_buf
= &tr
->max_buffer
;
832 struct trace_array_cpu
*data
= per_cpu_ptr(trace_buf
->data
, cpu
);
833 struct trace_array_cpu
*max_data
= per_cpu_ptr(max_buf
->data
, cpu
);
836 max_buf
->time_start
= data
->preempt_timestamp
;
838 max_data
->saved_latency
= tracing_max_latency
;
839 max_data
->critical_start
= data
->critical_start
;
840 max_data
->critical_end
= data
->critical_end
;
842 memcpy(max_data
->comm
, tsk
->comm
, TASK_COMM_LEN
);
843 max_data
->pid
= tsk
->pid
;
844 max_data
->uid
= task_uid(tsk
);
845 max_data
->nice
= tsk
->static_prio
- 20 - MAX_RT_PRIO
;
846 max_data
->policy
= tsk
->policy
;
847 max_data
->rt_priority
= tsk
->rt_priority
;
849 /* record this tasks comm */
850 tracing_record_cmdline(tsk
);
854 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
856 * @tsk: the task with the latency
857 * @cpu: The cpu that initiated the trace.
859 * Flip the buffers between the @tr and the max_tr and record information
860 * about which task was the cause of this latency.
863 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
865 struct ring_buffer
*buf
;
870 WARN_ON_ONCE(!irqs_disabled());
872 if (!tr
->allocated_snapshot
) {
873 /* Only the nop tracer should hit this when disabling */
874 WARN_ON_ONCE(tr
->current_trace
!= &nop_trace
);
878 arch_spin_lock(&ftrace_max_lock
);
880 buf
= tr
->trace_buffer
.buffer
;
881 tr
->trace_buffer
.buffer
= tr
->max_buffer
.buffer
;
882 tr
->max_buffer
.buffer
= buf
;
884 __update_max_tr(tr
, tsk
, cpu
);
885 arch_spin_unlock(&ftrace_max_lock
);
889 * update_max_tr_single - only copy one trace over, and reset the rest
891 * @tsk - task with the latency
892 * @cpu - the cpu of the buffer to copy.
894 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
897 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
904 WARN_ON_ONCE(!irqs_disabled());
905 if (WARN_ON_ONCE(!tr
->allocated_snapshot
))
908 arch_spin_lock(&ftrace_max_lock
);
910 ret
= ring_buffer_swap_cpu(tr
->max_buffer
.buffer
, tr
->trace_buffer
.buffer
, cpu
);
914 * We failed to swap the buffer due to a commit taking
915 * place on this CPU. We fail to record, but we reset
916 * the max trace buffer (no one writes directly to it)
917 * and flag that it failed.
919 trace_array_printk_buf(tr
->max_buffer
.buffer
, _THIS_IP_
,
920 "Failed to swap buffers due to commit in progress\n");
923 WARN_ON_ONCE(ret
&& ret
!= -EAGAIN
&& ret
!= -EBUSY
);
925 __update_max_tr(tr
, tsk
, cpu
);
926 arch_spin_unlock(&ftrace_max_lock
);
928 #endif /* CONFIG_TRACER_MAX_TRACE */
930 static void default_wait_pipe(struct trace_iterator
*iter
)
932 /* Iterators are static, they should be filled or empty */
933 if (trace_buffer_iter(iter
, iter
->cpu_file
))
936 ring_buffer_wait(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
939 #ifdef CONFIG_FTRACE_STARTUP_TEST
940 static int run_tracer_selftest(struct tracer
*type
)
942 struct trace_array
*tr
= &global_trace
;
943 struct tracer
*saved_tracer
= tr
->current_trace
;
946 if (!type
->selftest
|| tracing_selftest_disabled
)
950 * Run a selftest on this tracer.
951 * Here we reset the trace buffer, and set the current
952 * tracer to be this tracer. The tracer can then run some
953 * internal tracing to verify that everything is in order.
954 * If we fail, we do not register this tracer.
956 tracing_reset_online_cpus(&tr
->trace_buffer
);
958 tr
->current_trace
= type
;
960 #ifdef CONFIG_TRACER_MAX_TRACE
961 if (type
->use_max_tr
) {
962 /* If we expanded the buffers, make sure the max is expanded too */
963 if (ring_buffer_expanded
)
964 ring_buffer_resize(tr
->max_buffer
.buffer
, trace_buf_size
,
965 RING_BUFFER_ALL_CPUS
);
966 tr
->allocated_snapshot
= true;
970 /* the test is responsible for initializing and enabling */
971 pr_info("Testing tracer %s: ", type
->name
);
972 ret
= type
->selftest(type
, tr
);
973 /* the test is responsible for resetting too */
974 tr
->current_trace
= saved_tracer
;
976 printk(KERN_CONT
"FAILED!\n");
977 /* Add the warning after printing 'FAILED' */
981 /* Only reset on passing, to avoid touching corrupted buffers */
982 tracing_reset_online_cpus(&tr
->trace_buffer
);
984 #ifdef CONFIG_TRACER_MAX_TRACE
985 if (type
->use_max_tr
) {
986 tr
->allocated_snapshot
= false;
988 /* Shrink the max buffer again */
989 if (ring_buffer_expanded
)
990 ring_buffer_resize(tr
->max_buffer
.buffer
, 1,
991 RING_BUFFER_ALL_CPUS
);
995 printk(KERN_CONT
"PASSED\n");
999 static inline int run_tracer_selftest(struct tracer
*type
)
1003 #endif /* CONFIG_FTRACE_STARTUP_TEST */
1006 * register_tracer - register a tracer with the ftrace system.
1007 * @type - the plugin for the tracer
1009 * Register a new plugin tracer.
1011 int register_tracer(struct tracer
*type
)
1017 pr_info("Tracer must have a name\n");
1021 if (strlen(type
->name
) >= MAX_TRACER_SIZE
) {
1022 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE
);
1026 mutex_lock(&trace_types_lock
);
1028 tracing_selftest_running
= true;
1030 for (t
= trace_types
; t
; t
= t
->next
) {
1031 if (strcmp(type
->name
, t
->name
) == 0) {
1033 pr_info("Tracer %s already registered\n",
1040 if (!type
->set_flag
)
1041 type
->set_flag
= &dummy_set_flag
;
1043 type
->flags
= &dummy_tracer_flags
;
1045 if (!type
->flags
->opts
)
1046 type
->flags
->opts
= dummy_tracer_opt
;
1047 if (!type
->wait_pipe
)
1048 type
->wait_pipe
= default_wait_pipe
;
1050 ret
= run_tracer_selftest(type
);
1054 type
->next
= trace_types
;
1058 tracing_selftest_running
= false;
1059 mutex_unlock(&trace_types_lock
);
1061 if (ret
|| !default_bootup_tracer
)
1064 if (strncmp(default_bootup_tracer
, type
->name
, MAX_TRACER_SIZE
))
1067 printk(KERN_INFO
"Starting tracer '%s'\n", type
->name
);
1068 /* Do we want this tracer to start on bootup? */
1069 tracing_set_tracer(type
->name
);
1070 default_bootup_tracer
= NULL
;
1071 /* disable other selftests, since this will break it. */
1072 tracing_selftest_disabled
= true;
1073 #ifdef CONFIG_FTRACE_STARTUP_TEST
1074 printk(KERN_INFO
"Disabling FTRACE selftests due to running tracer '%s'\n",
1082 void tracing_reset(struct trace_buffer
*buf
, int cpu
)
1084 struct ring_buffer
*buffer
= buf
->buffer
;
1089 ring_buffer_record_disable(buffer
);
1091 /* Make sure all commits have finished */
1092 synchronize_sched();
1093 ring_buffer_reset_cpu(buffer
, cpu
);
1095 ring_buffer_record_enable(buffer
);
1098 void tracing_reset_online_cpus(struct trace_buffer
*buf
)
1100 struct ring_buffer
*buffer
= buf
->buffer
;
1106 ring_buffer_record_disable(buffer
);
1108 /* Make sure all commits have finished */
1109 synchronize_sched();
1111 buf
->time_start
= ftrace_now(buf
->cpu
);
1113 for_each_online_cpu(cpu
)
1114 ring_buffer_reset_cpu(buffer
, cpu
);
1116 ring_buffer_record_enable(buffer
);
1119 void tracing_reset_current(int cpu
)
1121 tracing_reset(&global_trace
.trace_buffer
, cpu
);
1124 void tracing_reset_all_online_cpus(void)
1126 struct trace_array
*tr
;
1128 mutex_lock(&trace_types_lock
);
1129 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
1130 tracing_reset_online_cpus(&tr
->trace_buffer
);
1131 #ifdef CONFIG_TRACER_MAX_TRACE
1132 tracing_reset_online_cpus(&tr
->max_buffer
);
1135 mutex_unlock(&trace_types_lock
);
1138 #define SAVED_CMDLINES 128
1139 #define NO_CMDLINE_MAP UINT_MAX
1140 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
1141 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
1142 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
1143 static int cmdline_idx
;
1144 static arch_spinlock_t trace_cmdline_lock
= __ARCH_SPIN_LOCK_UNLOCKED
;
1146 /* temporary disable recording */
1147 static atomic_t trace_record_cmdline_disabled __read_mostly
;
1149 static void trace_init_cmdlines(void)
1151 memset(&map_pid_to_cmdline
, NO_CMDLINE_MAP
, sizeof(map_pid_to_cmdline
));
1152 memset(&map_cmdline_to_pid
, NO_CMDLINE_MAP
, sizeof(map_cmdline_to_pid
));
1156 int is_tracing_stopped(void)
1158 return global_trace
.stop_count
;
1162 * ftrace_off_permanent - disable all ftrace code permanently
1164 * This should only be called when a serious anomally has
1165 * been detected. This will turn off the function tracing,
1166 * ring buffers, and other tracing utilites. It takes no
1167 * locks and can be called from any context.
1169 void ftrace_off_permanent(void)
1171 tracing_disabled
= 1;
1173 tracing_off_permanent();
1177 * tracing_start - quick start of the tracer
1179 * If tracing is enabled but was stopped by tracing_stop,
1180 * this will start the tracer back up.
1182 void tracing_start(void)
1184 struct ring_buffer
*buffer
;
1185 unsigned long flags
;
1187 if (tracing_disabled
)
1190 raw_spin_lock_irqsave(&global_trace
.start_lock
, flags
);
1191 if (--global_trace
.stop_count
) {
1192 if (global_trace
.stop_count
< 0) {
1193 /* Someone screwed up their debugging */
1195 global_trace
.stop_count
= 0;
1200 /* Prevent the buffers from switching */
1201 arch_spin_lock(&ftrace_max_lock
);
1203 buffer
= global_trace
.trace_buffer
.buffer
;
1205 ring_buffer_record_enable(buffer
);
1207 #ifdef CONFIG_TRACER_MAX_TRACE
1208 buffer
= global_trace
.max_buffer
.buffer
;
1210 ring_buffer_record_enable(buffer
);
1213 arch_spin_unlock(&ftrace_max_lock
);
1217 raw_spin_unlock_irqrestore(&global_trace
.start_lock
, flags
);
1220 static void tracing_start_tr(struct trace_array
*tr
)
1222 struct ring_buffer
*buffer
;
1223 unsigned long flags
;
1225 if (tracing_disabled
)
1228 /* If global, we need to also start the max tracer */
1229 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
1230 return tracing_start();
1232 raw_spin_lock_irqsave(&tr
->start_lock
, flags
);
1234 if (--tr
->stop_count
) {
1235 if (tr
->stop_count
< 0) {
1236 /* Someone screwed up their debugging */
1243 buffer
= tr
->trace_buffer
.buffer
;
1245 ring_buffer_record_enable(buffer
);
1248 raw_spin_unlock_irqrestore(&tr
->start_lock
, flags
);
1252 * tracing_stop - quick stop of the tracer
1254 * Light weight way to stop tracing. Use in conjunction with
1257 void tracing_stop(void)
1259 struct ring_buffer
*buffer
;
1260 unsigned long flags
;
1263 raw_spin_lock_irqsave(&global_trace
.start_lock
, flags
);
1264 if (global_trace
.stop_count
++)
1267 /* Prevent the buffers from switching */
1268 arch_spin_lock(&ftrace_max_lock
);
1270 buffer
= global_trace
.trace_buffer
.buffer
;
1272 ring_buffer_record_disable(buffer
);
1274 #ifdef CONFIG_TRACER_MAX_TRACE
1275 buffer
= global_trace
.max_buffer
.buffer
;
1277 ring_buffer_record_disable(buffer
);
1280 arch_spin_unlock(&ftrace_max_lock
);
1283 raw_spin_unlock_irqrestore(&global_trace
.start_lock
, flags
);
1286 static void tracing_stop_tr(struct trace_array
*tr
)
1288 struct ring_buffer
*buffer
;
1289 unsigned long flags
;
1291 /* If global, we need to also stop the max tracer */
1292 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
1293 return tracing_stop();
1295 raw_spin_lock_irqsave(&tr
->start_lock
, flags
);
1296 if (tr
->stop_count
++)
1299 buffer
= tr
->trace_buffer
.buffer
;
1301 ring_buffer_record_disable(buffer
);
1304 raw_spin_unlock_irqrestore(&tr
->start_lock
, flags
);
1307 void trace_stop_cmdline_recording(void);
1309 static void trace_save_cmdline(struct task_struct
*tsk
)
1313 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
1317 * It's not the end of the world if we don't get
1318 * the lock, but we also don't want to spin
1319 * nor do we want to disable interrupts,
1320 * so if we miss here, then better luck next time.
1322 if (!arch_spin_trylock(&trace_cmdline_lock
))
1325 idx
= map_pid_to_cmdline
[tsk
->pid
];
1326 if (idx
== NO_CMDLINE_MAP
) {
1327 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
1330 * Check whether the cmdline buffer at idx has a pid
1331 * mapped. We are going to overwrite that entry so we
1332 * need to clear the map_pid_to_cmdline. Otherwise we
1333 * would read the new comm for the old pid.
1335 pid
= map_cmdline_to_pid
[idx
];
1336 if (pid
!= NO_CMDLINE_MAP
)
1337 map_pid_to_cmdline
[pid
] = NO_CMDLINE_MAP
;
1339 map_cmdline_to_pid
[idx
] = tsk
->pid
;
1340 map_pid_to_cmdline
[tsk
->pid
] = idx
;
1345 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
1347 arch_spin_unlock(&trace_cmdline_lock
);
1350 void trace_find_cmdline(int pid
, char comm
[])
1355 strcpy(comm
, "<idle>");
1359 if (WARN_ON_ONCE(pid
< 0)) {
1360 strcpy(comm
, "<XXX>");
1364 if (pid
> PID_MAX_DEFAULT
) {
1365 strcpy(comm
, "<...>");
1370 arch_spin_lock(&trace_cmdline_lock
);
1371 map
= map_pid_to_cmdline
[pid
];
1372 if (map
!= NO_CMDLINE_MAP
)
1373 strcpy(comm
, saved_cmdlines
[map
]);
1375 strcpy(comm
, "<...>");
1377 arch_spin_unlock(&trace_cmdline_lock
);
1381 void tracing_record_cmdline(struct task_struct
*tsk
)
1383 if (atomic_read(&trace_record_cmdline_disabled
) || !tracing_is_on())
1386 if (!__this_cpu_read(trace_cmdline_save
))
1389 __this_cpu_write(trace_cmdline_save
, false);
1391 trace_save_cmdline(tsk
);
1395 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
,
1398 struct task_struct
*tsk
= current
;
1400 entry
->preempt_count
= pc
& 0xff;
1401 entry
->pid
= (tsk
) ? tsk
->pid
: 0;
1403 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1404 (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
1406 TRACE_FLAG_IRQS_NOSUPPORT
|
1408 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
1409 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
1410 (need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0);
1412 EXPORT_SYMBOL_GPL(tracing_generic_entry_update
);
1414 struct ring_buffer_event
*
1415 trace_buffer_lock_reserve(struct ring_buffer
*buffer
,
1418 unsigned long flags
, int pc
)
1420 struct ring_buffer_event
*event
;
1422 event
= ring_buffer_lock_reserve(buffer
, len
);
1423 if (event
!= NULL
) {
1424 struct trace_entry
*ent
= ring_buffer_event_data(event
);
1426 tracing_generic_entry_update(ent
, flags
, pc
);
1434 __buffer_unlock_commit(struct ring_buffer
*buffer
, struct ring_buffer_event
*event
)
1436 __this_cpu_write(trace_cmdline_save
, true);
1437 ring_buffer_unlock_commit(buffer
, event
);
1441 __trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1442 struct ring_buffer_event
*event
,
1443 unsigned long flags
, int pc
)
1445 __buffer_unlock_commit(buffer
, event
);
1447 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1448 ftrace_trace_userstack(buffer
, flags
, pc
);
1451 void trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1452 struct ring_buffer_event
*event
,
1453 unsigned long flags
, int pc
)
1455 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
);
1457 EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit
);
1459 struct ring_buffer_event
*
1460 trace_event_buffer_lock_reserve(struct ring_buffer
**current_rb
,
1461 struct ftrace_event_file
*ftrace_file
,
1462 int type
, unsigned long len
,
1463 unsigned long flags
, int pc
)
1465 *current_rb
= ftrace_file
->tr
->trace_buffer
.buffer
;
1466 return trace_buffer_lock_reserve(*current_rb
,
1467 type
, len
, flags
, pc
);
1469 EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve
);
1471 struct ring_buffer_event
*
1472 trace_current_buffer_lock_reserve(struct ring_buffer
**current_rb
,
1473 int type
, unsigned long len
,
1474 unsigned long flags
, int pc
)
1476 *current_rb
= global_trace
.trace_buffer
.buffer
;
1477 return trace_buffer_lock_reserve(*current_rb
,
1478 type
, len
, flags
, pc
);
1480 EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve
);
1482 void trace_current_buffer_unlock_commit(struct ring_buffer
*buffer
,
1483 struct ring_buffer_event
*event
,
1484 unsigned long flags
, int pc
)
1486 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
);
1488 EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit
);
1490 void trace_buffer_unlock_commit_regs(struct ring_buffer
*buffer
,
1491 struct ring_buffer_event
*event
,
1492 unsigned long flags
, int pc
,
1493 struct pt_regs
*regs
)
1495 __buffer_unlock_commit(buffer
, event
);
1497 ftrace_trace_stack_regs(buffer
, flags
, 0, pc
, regs
);
1498 ftrace_trace_userstack(buffer
, flags
, pc
);
1500 EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit_regs
);
1502 void trace_current_buffer_discard_commit(struct ring_buffer
*buffer
,
1503 struct ring_buffer_event
*event
)
1505 ring_buffer_discard_commit(buffer
, event
);
1507 EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit
);
1510 trace_function(struct trace_array
*tr
,
1511 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
1514 struct ftrace_event_call
*call
= &event_function
;
1515 struct ring_buffer
*buffer
= tr
->trace_buffer
.buffer
;
1516 struct ring_buffer_event
*event
;
1517 struct ftrace_entry
*entry
;
1519 /* If we are reading the ring buffer, don't trace */
1520 if (unlikely(__this_cpu_read(ftrace_cpu_disabled
)))
1523 event
= trace_buffer_lock_reserve(buffer
, TRACE_FN
, sizeof(*entry
),
1527 entry
= ring_buffer_event_data(event
);
1529 entry
->parent_ip
= parent_ip
;
1531 if (!filter_check_discard(call
, entry
, buffer
, event
))
1532 __buffer_unlock_commit(buffer
, event
);
1536 ftrace(struct trace_array
*tr
, struct trace_array_cpu
*data
,
1537 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
1540 if (likely(!atomic_read(&data
->disabled
)))
1541 trace_function(tr
, ip
, parent_ip
, flags
, pc
);
1544 #ifdef CONFIG_STACKTRACE
1546 #define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
1547 struct ftrace_stack
{
1548 unsigned long calls
[FTRACE_STACK_MAX_ENTRIES
];
1551 static DEFINE_PER_CPU(struct ftrace_stack
, ftrace_stack
);
1552 static DEFINE_PER_CPU(int, ftrace_stack_reserve
);
1554 static void __ftrace_trace_stack(struct ring_buffer
*buffer
,
1555 unsigned long flags
,
1556 int skip
, int pc
, struct pt_regs
*regs
)
1558 struct ftrace_event_call
*call
= &event_kernel_stack
;
1559 struct ring_buffer_event
*event
;
1560 struct stack_entry
*entry
;
1561 struct stack_trace trace
;
1563 int size
= FTRACE_STACK_ENTRIES
;
1565 trace
.nr_entries
= 0;
1569 * Since events can happen in NMIs there's no safe way to
1570 * use the per cpu ftrace_stacks. We reserve it and if an interrupt
1571 * or NMI comes in, it will just have to use the default
1572 * FTRACE_STACK_SIZE.
1574 preempt_disable_notrace();
1576 use_stack
= __this_cpu_inc_return(ftrace_stack_reserve
);
1578 * We don't need any atomic variables, just a barrier.
1579 * If an interrupt comes in, we don't care, because it would
1580 * have exited and put the counter back to what we want.
1581 * We just need a barrier to keep gcc from moving things
1585 if (use_stack
== 1) {
1586 trace
.entries
= &__get_cpu_var(ftrace_stack
).calls
[0];
1587 trace
.max_entries
= FTRACE_STACK_MAX_ENTRIES
;
1590 save_stack_trace_regs(regs
, &trace
);
1592 save_stack_trace(&trace
);
1594 if (trace
.nr_entries
> size
)
1595 size
= trace
.nr_entries
;
1597 /* From now on, use_stack is a boolean */
1600 size
*= sizeof(unsigned long);
1602 event
= trace_buffer_lock_reserve(buffer
, TRACE_STACK
,
1603 sizeof(*entry
) + size
, flags
, pc
);
1606 entry
= ring_buffer_event_data(event
);
1608 memset(&entry
->caller
, 0, size
);
1611 memcpy(&entry
->caller
, trace
.entries
,
1612 trace
.nr_entries
* sizeof(unsigned long));
1614 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1615 trace
.entries
= entry
->caller
;
1617 save_stack_trace_regs(regs
, &trace
);
1619 save_stack_trace(&trace
);
1622 entry
->size
= trace
.nr_entries
;
1624 if (!filter_check_discard(call
, entry
, buffer
, event
))
1625 __buffer_unlock_commit(buffer
, event
);
1628 /* Again, don't let gcc optimize things here */
1630 __this_cpu_dec(ftrace_stack_reserve
);
1631 preempt_enable_notrace();
1635 void ftrace_trace_stack_regs(struct ring_buffer
*buffer
, unsigned long flags
,
1636 int skip
, int pc
, struct pt_regs
*regs
)
1638 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1641 __ftrace_trace_stack(buffer
, flags
, skip
, pc
, regs
);
1644 void ftrace_trace_stack(struct ring_buffer
*buffer
, unsigned long flags
,
1647 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1650 __ftrace_trace_stack(buffer
, flags
, skip
, pc
, NULL
);
1653 void __trace_stack(struct trace_array
*tr
, unsigned long flags
, int skip
,
1656 __ftrace_trace_stack(tr
->trace_buffer
.buffer
, flags
, skip
, pc
, NULL
);
1660 * trace_dump_stack - record a stack back trace in the trace buffer
1661 * @skip: Number of functions to skip (helper handlers)
1663 void trace_dump_stack(int skip
)
1665 unsigned long flags
;
1667 if (tracing_disabled
|| tracing_selftest_running
)
1670 local_save_flags(flags
);
1673 * Skip 3 more, seems to get us at the caller of
1677 __ftrace_trace_stack(global_trace
.trace_buffer
.buffer
,
1678 flags
, skip
, preempt_count(), NULL
);
1681 static DEFINE_PER_CPU(int, user_stack_count
);
1684 ftrace_trace_userstack(struct ring_buffer
*buffer
, unsigned long flags
, int pc
)
1686 struct ftrace_event_call
*call
= &event_user_stack
;
1687 struct ring_buffer_event
*event
;
1688 struct userstack_entry
*entry
;
1689 struct stack_trace trace
;
1691 if (!(trace_flags
& TRACE_ITER_USERSTACKTRACE
))
1695 * NMIs can not handle page faults, even with fix ups.
1696 * The save user stack can (and often does) fault.
1698 if (unlikely(in_nmi()))
1702 * prevent recursion, since the user stack tracing may
1703 * trigger other kernel events.
1706 if (__this_cpu_read(user_stack_count
))
1709 __this_cpu_inc(user_stack_count
);
1711 event
= trace_buffer_lock_reserve(buffer
, TRACE_USER_STACK
,
1712 sizeof(*entry
), flags
, pc
);
1714 goto out_drop_count
;
1715 entry
= ring_buffer_event_data(event
);
1717 entry
->tgid
= current
->tgid
;
1718 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
1720 trace
.nr_entries
= 0;
1721 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1723 trace
.entries
= entry
->caller
;
1725 save_stack_trace_user(&trace
);
1726 if (!filter_check_discard(call
, entry
, buffer
, event
))
1727 __buffer_unlock_commit(buffer
, event
);
1730 __this_cpu_dec(user_stack_count
);
1736 static void __trace_userstack(struct trace_array
*tr
, unsigned long flags
)
1738 ftrace_trace_userstack(tr
, flags
, preempt_count());
1742 #endif /* CONFIG_STACKTRACE */
1744 /* created for use with alloc_percpu */
1745 struct trace_buffer_struct
{
1746 char buffer
[TRACE_BUF_SIZE
];
1749 static struct trace_buffer_struct
*trace_percpu_buffer
;
1750 static struct trace_buffer_struct
*trace_percpu_sirq_buffer
;
1751 static struct trace_buffer_struct
*trace_percpu_irq_buffer
;
1752 static struct trace_buffer_struct
*trace_percpu_nmi_buffer
;
1755 * The buffer used is dependent on the context. There is a per cpu
1756 * buffer for normal context, softirq contex, hard irq context and
1757 * for NMI context. Thise allows for lockless recording.
1759 * Note, if the buffers failed to be allocated, then this returns NULL
1761 static char *get_trace_buf(void)
1763 struct trace_buffer_struct
*percpu_buffer
;
1766 * If we have allocated per cpu buffers, then we do not
1767 * need to do any locking.
1770 percpu_buffer
= trace_percpu_nmi_buffer
;
1772 percpu_buffer
= trace_percpu_irq_buffer
;
1773 else if (in_softirq())
1774 percpu_buffer
= trace_percpu_sirq_buffer
;
1776 percpu_buffer
= trace_percpu_buffer
;
1781 return this_cpu_ptr(&percpu_buffer
->buffer
[0]);
1784 static int alloc_percpu_trace_buffer(void)
1786 struct trace_buffer_struct
*buffers
;
1787 struct trace_buffer_struct
*sirq_buffers
;
1788 struct trace_buffer_struct
*irq_buffers
;
1789 struct trace_buffer_struct
*nmi_buffers
;
1791 buffers
= alloc_percpu(struct trace_buffer_struct
);
1795 sirq_buffers
= alloc_percpu(struct trace_buffer_struct
);
1799 irq_buffers
= alloc_percpu(struct trace_buffer_struct
);
1803 nmi_buffers
= alloc_percpu(struct trace_buffer_struct
);
1807 trace_percpu_buffer
= buffers
;
1808 trace_percpu_sirq_buffer
= sirq_buffers
;
1809 trace_percpu_irq_buffer
= irq_buffers
;
1810 trace_percpu_nmi_buffer
= nmi_buffers
;
1815 free_percpu(irq_buffers
);
1817 free_percpu(sirq_buffers
);
1819 free_percpu(buffers
);
1821 WARN(1, "Could not allocate percpu trace_printk buffer");
1825 static int buffers_allocated
;
1827 void trace_printk_init_buffers(void)
1829 if (buffers_allocated
)
1832 if (alloc_percpu_trace_buffer())
1835 pr_info("ftrace: Allocated trace_printk buffers\n");
1837 /* Expand the buffers to set size */
1838 tracing_update_buffers();
1840 buffers_allocated
= 1;
1843 * trace_printk_init_buffers() can be called by modules.
1844 * If that happens, then we need to start cmdline recording
1845 * directly here. If the global_trace.buffer is already
1846 * allocated here, then this was called by module code.
1848 if (global_trace
.trace_buffer
.buffer
)
1849 tracing_start_cmdline_record();
1852 void trace_printk_start_comm(void)
1854 /* Start tracing comms if trace printk is set */
1855 if (!buffers_allocated
)
1857 tracing_start_cmdline_record();
1860 static void trace_printk_start_stop_comm(int enabled
)
1862 if (!buffers_allocated
)
1866 tracing_start_cmdline_record();
1868 tracing_stop_cmdline_record();
1872 * trace_vbprintk - write binary msg to tracing buffer
1875 int trace_vbprintk(unsigned long ip
, const char *fmt
, va_list args
)
1877 struct ftrace_event_call
*call
= &event_bprint
;
1878 struct ring_buffer_event
*event
;
1879 struct ring_buffer
*buffer
;
1880 struct trace_array
*tr
= &global_trace
;
1881 struct bprint_entry
*entry
;
1882 unsigned long flags
;
1884 int len
= 0, size
, pc
;
1886 if (unlikely(tracing_selftest_running
|| tracing_disabled
))
1889 /* Don't pollute graph traces with trace_vprintk internals */
1890 pause_graph_tracing();
1892 pc
= preempt_count();
1893 preempt_disable_notrace();
1895 tbuffer
= get_trace_buf();
1901 len
= vbin_printf((u32
*)tbuffer
, TRACE_BUF_SIZE
/sizeof(int), fmt
, args
);
1903 if (len
> TRACE_BUF_SIZE
/sizeof(int) || len
< 0)
1906 local_save_flags(flags
);
1907 size
= sizeof(*entry
) + sizeof(u32
) * len
;
1908 buffer
= tr
->trace_buffer
.buffer
;
1909 event
= trace_buffer_lock_reserve(buffer
, TRACE_BPRINT
, size
,
1913 entry
= ring_buffer_event_data(event
);
1917 memcpy(entry
->buf
, tbuffer
, sizeof(u32
) * len
);
1918 if (!filter_check_discard(call
, entry
, buffer
, event
)) {
1919 __buffer_unlock_commit(buffer
, event
);
1920 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1924 preempt_enable_notrace();
1925 unpause_graph_tracing();
1929 EXPORT_SYMBOL_GPL(trace_vbprintk
);
1932 __trace_array_vprintk(struct ring_buffer
*buffer
,
1933 unsigned long ip
, const char *fmt
, va_list args
)
1935 struct ftrace_event_call
*call
= &event_print
;
1936 struct ring_buffer_event
*event
;
1937 int len
= 0, size
, pc
;
1938 struct print_entry
*entry
;
1939 unsigned long flags
;
1942 if (tracing_disabled
|| tracing_selftest_running
)
1945 /* Don't pollute graph traces with trace_vprintk internals */
1946 pause_graph_tracing();
1948 pc
= preempt_count();
1949 preempt_disable_notrace();
1952 tbuffer
= get_trace_buf();
1958 len
= vsnprintf(tbuffer
, TRACE_BUF_SIZE
, fmt
, args
);
1959 if (len
> TRACE_BUF_SIZE
)
1962 local_save_flags(flags
);
1963 size
= sizeof(*entry
) + len
+ 1;
1964 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, size
,
1968 entry
= ring_buffer_event_data(event
);
1971 memcpy(&entry
->buf
, tbuffer
, len
);
1972 entry
->buf
[len
] = '\0';
1973 if (!filter_check_discard(call
, entry
, buffer
, event
)) {
1974 __buffer_unlock_commit(buffer
, event
);
1975 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1978 preempt_enable_notrace();
1979 unpause_graph_tracing();
1984 int trace_array_vprintk(struct trace_array
*tr
,
1985 unsigned long ip
, const char *fmt
, va_list args
)
1987 return __trace_array_vprintk(tr
->trace_buffer
.buffer
, ip
, fmt
, args
);
1990 int trace_array_printk(struct trace_array
*tr
,
1991 unsigned long ip
, const char *fmt
, ...)
1996 if (!(trace_flags
& TRACE_ITER_PRINTK
))
2000 ret
= trace_array_vprintk(tr
, ip
, fmt
, ap
);
2005 int trace_array_printk_buf(struct ring_buffer
*buffer
,
2006 unsigned long ip
, const char *fmt
, ...)
2011 if (!(trace_flags
& TRACE_ITER_PRINTK
))
2015 ret
= __trace_array_vprintk(buffer
, ip
, fmt
, ap
);
2020 int trace_vprintk(unsigned long ip
, const char *fmt
, va_list args
)
2022 return trace_array_vprintk(&global_trace
, ip
, fmt
, args
);
2024 EXPORT_SYMBOL_GPL(trace_vprintk
);
2026 static void trace_iterator_increment(struct trace_iterator
*iter
)
2028 struct ring_buffer_iter
*buf_iter
= trace_buffer_iter(iter
, iter
->cpu
);
2032 ring_buffer_read(buf_iter
, NULL
);
2035 static struct trace_entry
*
2036 peek_next_entry(struct trace_iterator
*iter
, int cpu
, u64
*ts
,
2037 unsigned long *lost_events
)
2039 struct ring_buffer_event
*event
;
2040 struct ring_buffer_iter
*buf_iter
= trace_buffer_iter(iter
, cpu
);
2043 event
= ring_buffer_iter_peek(buf_iter
, ts
);
2045 event
= ring_buffer_peek(iter
->trace_buffer
->buffer
, cpu
, ts
,
2049 iter
->ent_size
= ring_buffer_event_length(event
);
2050 return ring_buffer_event_data(event
);
2056 static struct trace_entry
*
2057 __find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
,
2058 unsigned long *missing_events
, u64
*ent_ts
)
2060 struct ring_buffer
*buffer
= iter
->trace_buffer
->buffer
;
2061 struct trace_entry
*ent
, *next
= NULL
;
2062 unsigned long lost_events
= 0, next_lost
= 0;
2063 int cpu_file
= iter
->cpu_file
;
2064 u64 next_ts
= 0, ts
;
2070 * If we are in a per_cpu trace file, don't bother by iterating over
2071 * all cpu and peek directly.
2073 if (cpu_file
> RING_BUFFER_ALL_CPUS
) {
2074 if (ring_buffer_empty_cpu(buffer
, cpu_file
))
2076 ent
= peek_next_entry(iter
, cpu_file
, ent_ts
, missing_events
);
2078 *ent_cpu
= cpu_file
;
2083 for_each_tracing_cpu(cpu
) {
2085 if (ring_buffer_empty_cpu(buffer
, cpu
))
2088 ent
= peek_next_entry(iter
, cpu
, &ts
, &lost_events
);
2091 * Pick the entry with the smallest timestamp:
2093 if (ent
&& (!next
|| ts
< next_ts
)) {
2097 next_lost
= lost_events
;
2098 next_size
= iter
->ent_size
;
2102 iter
->ent_size
= next_size
;
2105 *ent_cpu
= next_cpu
;
2111 *missing_events
= next_lost
;
2116 /* Find the next real entry, without updating the iterator itself */
2117 struct trace_entry
*trace_find_next_entry(struct trace_iterator
*iter
,
2118 int *ent_cpu
, u64
*ent_ts
)
2120 return __find_next_entry(iter
, ent_cpu
, NULL
, ent_ts
);
2123 /* Find the next real entry, and increment the iterator to the next entry */
2124 void *trace_find_next_entry_inc(struct trace_iterator
*iter
)
2126 iter
->ent
= __find_next_entry(iter
, &iter
->cpu
,
2127 &iter
->lost_events
, &iter
->ts
);
2130 trace_iterator_increment(iter
);
2132 return iter
->ent
? iter
: NULL
;
2135 static void trace_consume(struct trace_iterator
*iter
)
2137 ring_buffer_consume(iter
->trace_buffer
->buffer
, iter
->cpu
, &iter
->ts
,
2138 &iter
->lost_events
);
2141 static void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
2143 struct trace_iterator
*iter
= m
->private;
2147 WARN_ON_ONCE(iter
->leftover
);
2151 /* can't go backwards */
2156 ent
= trace_find_next_entry_inc(iter
);
2160 while (ent
&& iter
->idx
< i
)
2161 ent
= trace_find_next_entry_inc(iter
);
2168 void tracing_iter_reset(struct trace_iterator
*iter
, int cpu
)
2170 struct ring_buffer_event
*event
;
2171 struct ring_buffer_iter
*buf_iter
;
2172 unsigned long entries
= 0;
2175 per_cpu_ptr(iter
->trace_buffer
->data
, cpu
)->skipped_entries
= 0;
2177 buf_iter
= trace_buffer_iter(iter
, cpu
);
2181 ring_buffer_iter_reset(buf_iter
);
2184 * We could have the case with the max latency tracers
2185 * that a reset never took place on a cpu. This is evident
2186 * by the timestamp being before the start of the buffer.
2188 while ((event
= ring_buffer_iter_peek(buf_iter
, &ts
))) {
2189 if (ts
>= iter
->trace_buffer
->time_start
)
2192 ring_buffer_read(buf_iter
, NULL
);
2195 per_cpu_ptr(iter
->trace_buffer
->data
, cpu
)->skipped_entries
= entries
;
2199 * The current tracer is copied to avoid a global locking
2202 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
2204 struct trace_iterator
*iter
= m
->private;
2205 struct trace_array
*tr
= iter
->tr
;
2206 int cpu_file
= iter
->cpu_file
;
2212 * copy the tracer to avoid using a global lock all around.
2213 * iter->trace is a copy of current_trace, the pointer to the
2214 * name may be used instead of a strcmp(), as iter->trace->name
2215 * will point to the same string as current_trace->name.
2217 mutex_lock(&trace_types_lock
);
2218 if (unlikely(tr
->current_trace
&& iter
->trace
->name
!= tr
->current_trace
->name
))
2219 *iter
->trace
= *tr
->current_trace
;
2220 mutex_unlock(&trace_types_lock
);
2222 #ifdef CONFIG_TRACER_MAX_TRACE
2223 if (iter
->snapshot
&& iter
->trace
->use_max_tr
)
2224 return ERR_PTR(-EBUSY
);
2227 if (!iter
->snapshot
)
2228 atomic_inc(&trace_record_cmdline_disabled
);
2230 if (*pos
!= iter
->pos
) {
2235 if (cpu_file
== RING_BUFFER_ALL_CPUS
) {
2236 for_each_tracing_cpu(cpu
)
2237 tracing_iter_reset(iter
, cpu
);
2239 tracing_iter_reset(iter
, cpu_file
);
2242 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
2247 * If we overflowed the seq_file before, then we want
2248 * to just reuse the trace_seq buffer again.
2254 p
= s_next(m
, p
, &l
);
2258 trace_event_read_lock();
2259 trace_access_lock(cpu_file
);
2263 static void s_stop(struct seq_file
*m
, void *p
)
2265 struct trace_iterator
*iter
= m
->private;
2267 #ifdef CONFIG_TRACER_MAX_TRACE
2268 if (iter
->snapshot
&& iter
->trace
->use_max_tr
)
2272 if (!iter
->snapshot
)
2273 atomic_dec(&trace_record_cmdline_disabled
);
2275 trace_access_unlock(iter
->cpu_file
);
2276 trace_event_read_unlock();
2280 get_total_entries(struct trace_buffer
*buf
,
2281 unsigned long *total
, unsigned long *entries
)
2283 unsigned long count
;
2289 for_each_tracing_cpu(cpu
) {
2290 count
= ring_buffer_entries_cpu(buf
->buffer
, cpu
);
2292 * If this buffer has skipped entries, then we hold all
2293 * entries for the trace and we need to ignore the
2294 * ones before the time stamp.
2296 if (per_cpu_ptr(buf
->data
, cpu
)->skipped_entries
) {
2297 count
-= per_cpu_ptr(buf
->data
, cpu
)->skipped_entries
;
2298 /* total is the same as the entries */
2302 ring_buffer_overrun_cpu(buf
->buffer
, cpu
);
2307 static void print_lat_help_header(struct seq_file
*m
)
2309 seq_puts(m
, "# _------=> CPU# \n");
2310 seq_puts(m
, "# / _-----=> irqs-off \n");
2311 seq_puts(m
, "# | / _----=> need-resched \n");
2312 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
2313 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
2314 seq_puts(m
, "# |||| / delay \n");
2315 seq_puts(m
, "# cmd pid ||||| time | caller \n");
2316 seq_puts(m
, "# \\ / ||||| \\ | / \n");
2319 static void print_event_info(struct trace_buffer
*buf
, struct seq_file
*m
)
2321 unsigned long total
;
2322 unsigned long entries
;
2324 get_total_entries(buf
, &total
, &entries
);
2325 seq_printf(m
, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
2326 entries
, total
, num_online_cpus());
2330 static void print_func_help_header(struct trace_buffer
*buf
, struct seq_file
*m
)
2332 print_event_info(buf
, m
);
2333 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
2334 seq_puts(m
, "# | | | | |\n");
2337 static void print_func_help_header_irq(struct trace_buffer
*buf
, struct seq_file
*m
)
2339 print_event_info(buf
, m
);
2340 seq_puts(m
, "# _-----=> irqs-off\n");
2341 seq_puts(m
, "# / _----=> need-resched\n");
2342 seq_puts(m
, "# | / _---=> hardirq/softirq\n");
2343 seq_puts(m
, "# || / _--=> preempt-depth\n");
2344 seq_puts(m
, "# ||| / delay\n");
2345 seq_puts(m
, "# TASK-PID CPU# |||| TIMESTAMP FUNCTION\n");
2346 seq_puts(m
, "# | | | |||| | |\n");
2350 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
2352 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
2353 struct trace_buffer
*buf
= iter
->trace_buffer
;
2354 struct trace_array_cpu
*data
= per_cpu_ptr(buf
->data
, buf
->cpu
);
2355 struct tracer
*type
= iter
->trace
;
2356 unsigned long entries
;
2357 unsigned long total
;
2358 const char *name
= "preemption";
2362 get_total_entries(buf
, &total
, &entries
);
2364 seq_printf(m
, "# %s latency trace v1.1.5 on %s\n",
2366 seq_puts(m
, "# -----------------------------------"
2367 "---------------------------------\n");
2368 seq_printf(m
, "# latency: %lu us, #%lu/%lu, CPU#%d |"
2369 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
2370 nsecs_to_usecs(data
->saved_latency
),
2374 #if defined(CONFIG_PREEMPT_NONE)
2376 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
2378 #elif defined(CONFIG_PREEMPT)
2383 /* These are reserved for later use */
2386 seq_printf(m
, " #P:%d)\n", num_online_cpus());
2390 seq_puts(m
, "# -----------------\n");
2391 seq_printf(m
, "# | task: %.16s-%d "
2392 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
2393 data
->comm
, data
->pid
,
2394 from_kuid_munged(seq_user_ns(m
), data
->uid
), data
->nice
,
2395 data
->policy
, data
->rt_priority
);
2396 seq_puts(m
, "# -----------------\n");
2398 if (data
->critical_start
) {
2399 seq_puts(m
, "# => started at: ");
2400 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
2401 trace_print_seq(m
, &iter
->seq
);
2402 seq_puts(m
, "\n# => ended at: ");
2403 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
2404 trace_print_seq(m
, &iter
->seq
);
2405 seq_puts(m
, "\n#\n");
2411 static void test_cpu_buff_start(struct trace_iterator
*iter
)
2413 struct trace_seq
*s
= &iter
->seq
;
2415 if (!(trace_flags
& TRACE_ITER_ANNOTATE
))
2418 if (!(iter
->iter_flags
& TRACE_FILE_ANNOTATE
))
2421 if (cpumask_test_cpu(iter
->cpu
, iter
->started
))
2424 if (per_cpu_ptr(iter
->trace_buffer
->data
, iter
->cpu
)->skipped_entries
)
2427 cpumask_set_cpu(iter
->cpu
, iter
->started
);
2429 /* Don't print started cpu buffer for the first entry of the trace */
2431 trace_seq_printf(s
, "##### CPU %u buffer started ####\n",
2435 static enum print_line_t
print_trace_fmt(struct trace_iterator
*iter
)
2437 struct trace_seq
*s
= &iter
->seq
;
2438 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
2439 struct trace_entry
*entry
;
2440 struct trace_event
*event
;
2444 test_cpu_buff_start(iter
);
2446 event
= ftrace_find_event(entry
->type
);
2448 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2449 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
2450 if (!trace_print_lat_context(iter
))
2453 if (!trace_print_context(iter
))
2459 return event
->funcs
->trace(iter
, sym_flags
, event
);
2461 if (!trace_seq_printf(s
, "Unknown type %d\n", entry
->type
))
2464 return TRACE_TYPE_HANDLED
;
2466 return TRACE_TYPE_PARTIAL_LINE
;
2469 static enum print_line_t
print_raw_fmt(struct trace_iterator
*iter
)
2471 struct trace_seq
*s
= &iter
->seq
;
2472 struct trace_entry
*entry
;
2473 struct trace_event
*event
;
2477 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2478 if (!trace_seq_printf(s
, "%d %d %llu ",
2479 entry
->pid
, iter
->cpu
, iter
->ts
))
2483 event
= ftrace_find_event(entry
->type
);
2485 return event
->funcs
->raw(iter
, 0, event
);
2487 if (!trace_seq_printf(s
, "%d ?\n", entry
->type
))
2490 return TRACE_TYPE_HANDLED
;
2492 return TRACE_TYPE_PARTIAL_LINE
;
2495 static enum print_line_t
print_hex_fmt(struct trace_iterator
*iter
)
2497 struct trace_seq
*s
= &iter
->seq
;
2498 unsigned char newline
= '\n';
2499 struct trace_entry
*entry
;
2500 struct trace_event
*event
;
2504 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2505 SEQ_PUT_HEX_FIELD_RET(s
, entry
->pid
);
2506 SEQ_PUT_HEX_FIELD_RET(s
, iter
->cpu
);
2507 SEQ_PUT_HEX_FIELD_RET(s
, iter
->ts
);
2510 event
= ftrace_find_event(entry
->type
);
2512 enum print_line_t ret
= event
->funcs
->hex(iter
, 0, event
);
2513 if (ret
!= TRACE_TYPE_HANDLED
)
2517 SEQ_PUT_FIELD_RET(s
, newline
);
2519 return TRACE_TYPE_HANDLED
;
2522 static enum print_line_t
print_bin_fmt(struct trace_iterator
*iter
)
2524 struct trace_seq
*s
= &iter
->seq
;
2525 struct trace_entry
*entry
;
2526 struct trace_event
*event
;
2530 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2531 SEQ_PUT_FIELD_RET(s
, entry
->pid
);
2532 SEQ_PUT_FIELD_RET(s
, iter
->cpu
);
2533 SEQ_PUT_FIELD_RET(s
, iter
->ts
);
2536 event
= ftrace_find_event(entry
->type
);
2537 return event
? event
->funcs
->binary(iter
, 0, event
) :
2541 int trace_empty(struct trace_iterator
*iter
)
2543 struct ring_buffer_iter
*buf_iter
;
2546 /* If we are looking at one CPU buffer, only check that one */
2547 if (iter
->cpu_file
!= RING_BUFFER_ALL_CPUS
) {
2548 cpu
= iter
->cpu_file
;
2549 buf_iter
= trace_buffer_iter(iter
, cpu
);
2551 if (!ring_buffer_iter_empty(buf_iter
))
2554 if (!ring_buffer_empty_cpu(iter
->trace_buffer
->buffer
, cpu
))
2560 for_each_tracing_cpu(cpu
) {
2561 buf_iter
= trace_buffer_iter(iter
, cpu
);
2563 if (!ring_buffer_iter_empty(buf_iter
))
2566 if (!ring_buffer_empty_cpu(iter
->trace_buffer
->buffer
, cpu
))
2574 /* Called with trace_event_read_lock() held. */
2575 enum print_line_t
print_trace_line(struct trace_iterator
*iter
)
2577 enum print_line_t ret
;
2579 if (iter
->lost_events
&&
2580 !trace_seq_printf(&iter
->seq
, "CPU:%d [LOST %lu EVENTS]\n",
2581 iter
->cpu
, iter
->lost_events
))
2582 return TRACE_TYPE_PARTIAL_LINE
;
2584 if (iter
->trace
&& iter
->trace
->print_line
) {
2585 ret
= iter
->trace
->print_line(iter
);
2586 if (ret
!= TRACE_TYPE_UNHANDLED
)
2590 if (iter
->ent
->type
== TRACE_BPUTS
&&
2591 trace_flags
& TRACE_ITER_PRINTK
&&
2592 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2593 return trace_print_bputs_msg_only(iter
);
2595 if (iter
->ent
->type
== TRACE_BPRINT
&&
2596 trace_flags
& TRACE_ITER_PRINTK
&&
2597 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2598 return trace_print_bprintk_msg_only(iter
);
2600 if (iter
->ent
->type
== TRACE_PRINT
&&
2601 trace_flags
& TRACE_ITER_PRINTK
&&
2602 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2603 return trace_print_printk_msg_only(iter
);
2605 if (trace_flags
& TRACE_ITER_BIN
)
2606 return print_bin_fmt(iter
);
2608 if (trace_flags
& TRACE_ITER_HEX
)
2609 return print_hex_fmt(iter
);
2611 if (trace_flags
& TRACE_ITER_RAW
)
2612 return print_raw_fmt(iter
);
2614 return print_trace_fmt(iter
);
2617 void trace_latency_header(struct seq_file
*m
)
2619 struct trace_iterator
*iter
= m
->private;
2621 /* print nothing if the buffers are empty */
2622 if (trace_empty(iter
))
2625 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
)
2626 print_trace_header(m
, iter
);
2628 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2629 print_lat_help_header(m
);
2632 void trace_default_header(struct seq_file
*m
)
2634 struct trace_iterator
*iter
= m
->private;
2636 if (!(trace_flags
& TRACE_ITER_CONTEXT_INFO
))
2639 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
2640 /* print nothing if the buffers are empty */
2641 if (trace_empty(iter
))
2643 print_trace_header(m
, iter
);
2644 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2645 print_lat_help_header(m
);
2647 if (!(trace_flags
& TRACE_ITER_VERBOSE
)) {
2648 if (trace_flags
& TRACE_ITER_IRQ_INFO
)
2649 print_func_help_header_irq(iter
->trace_buffer
, m
);
2651 print_func_help_header(iter
->trace_buffer
, m
);
2656 static void test_ftrace_alive(struct seq_file
*m
)
2658 if (!ftrace_is_dead())
2660 seq_printf(m
, "# WARNING: FUNCTION TRACING IS CORRUPTED\n");
2661 seq_printf(m
, "# MAY BE MISSING FUNCTION EVENTS\n");
2664 #ifdef CONFIG_TRACER_MAX_TRACE
2665 static void show_snapshot_main_help(struct seq_file
*m
)
2667 seq_printf(m
, "# echo 0 > snapshot : Clears and frees snapshot buffer\n");
2668 seq_printf(m
, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
2669 seq_printf(m
, "# Takes a snapshot of the main buffer.\n");
2670 seq_printf(m
, "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate)\n");
2671 seq_printf(m
, "# (Doesn't have to be '2' works with any number that\n");
2672 seq_printf(m
, "# is not a '0' or '1')\n");
2675 static void show_snapshot_percpu_help(struct seq_file
*m
)
2677 seq_printf(m
, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
2678 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
2679 seq_printf(m
, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
2680 seq_printf(m
, "# Takes a snapshot of the main buffer for this cpu.\n");
2682 seq_printf(m
, "# echo 1 > snapshot : Not supported with this kernel.\n");
2683 seq_printf(m
, "# Must use main snapshot file to allocate.\n");
2685 seq_printf(m
, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n");
2686 seq_printf(m
, "# (Doesn't have to be '2' works with any number that\n");
2687 seq_printf(m
, "# is not a '0' or '1')\n");
2690 static void print_snapshot_help(struct seq_file
*m
, struct trace_iterator
*iter
)
2692 if (iter
->tr
->allocated_snapshot
)
2693 seq_printf(m
, "#\n# * Snapshot is allocated *\n#\n");
2695 seq_printf(m
, "#\n# * Snapshot is freed *\n#\n");
2697 seq_printf(m
, "# Snapshot commands:\n");
2698 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
)
2699 show_snapshot_main_help(m
);
2701 show_snapshot_percpu_help(m
);
2704 /* Should never be called */
2705 static inline void print_snapshot_help(struct seq_file
*m
, struct trace_iterator
*iter
) { }
2708 static int s_show(struct seq_file
*m
, void *v
)
2710 struct trace_iterator
*iter
= v
;
2713 if (iter
->ent
== NULL
) {
2715 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
2717 test_ftrace_alive(m
);
2719 if (iter
->snapshot
&& trace_empty(iter
))
2720 print_snapshot_help(m
, iter
);
2721 else if (iter
->trace
&& iter
->trace
->print_header
)
2722 iter
->trace
->print_header(m
);
2724 trace_default_header(m
);
2726 } else if (iter
->leftover
) {
2728 * If we filled the seq_file buffer earlier, we
2729 * want to just show it now.
2731 ret
= trace_print_seq(m
, &iter
->seq
);
2733 /* ret should this time be zero, but you never know */
2734 iter
->leftover
= ret
;
2737 print_trace_line(iter
);
2738 ret
= trace_print_seq(m
, &iter
->seq
);
2740 * If we overflow the seq_file buffer, then it will
2741 * ask us for this data again at start up.
2743 * ret is 0 if seq_file write succeeded.
2746 iter
->leftover
= ret
;
2752 static const struct seq_operations tracer_seq_ops
= {
2759 static struct trace_iterator
*
2760 __tracing_open(struct inode
*inode
, struct file
*file
, bool snapshot
)
2762 struct trace_cpu
*tc
= inode
->i_private
;
2763 struct trace_array
*tr
= tc
->tr
;
2764 struct trace_iterator
*iter
;
2767 if (tracing_disabled
)
2768 return ERR_PTR(-ENODEV
);
2770 iter
= __seq_open_private(file
, &tracer_seq_ops
, sizeof(*iter
));
2772 return ERR_PTR(-ENOMEM
);
2774 iter
->buffer_iter
= kzalloc(sizeof(*iter
->buffer_iter
) * num_possible_cpus(),
2776 if (!iter
->buffer_iter
)
2780 * We make a copy of the current tracer to avoid concurrent
2781 * changes on it while we are reading.
2783 mutex_lock(&trace_types_lock
);
2784 iter
->trace
= kzalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
2788 *iter
->trace
= *tr
->current_trace
;
2790 if (!zalloc_cpumask_var(&iter
->started
, GFP_KERNEL
))
2795 #ifdef CONFIG_TRACER_MAX_TRACE
2796 /* Currently only the top directory has a snapshot */
2797 if (tr
->current_trace
->print_max
|| snapshot
)
2798 iter
->trace_buffer
= &tr
->max_buffer
;
2801 iter
->trace_buffer
= &tr
->trace_buffer
;
2802 iter
->snapshot
= snapshot
;
2804 mutex_init(&iter
->mutex
);
2805 iter
->cpu_file
= tc
->cpu
;
2807 /* Notify the tracer early; before we stop tracing. */
2808 if (iter
->trace
&& iter
->trace
->open
)
2809 iter
->trace
->open(iter
);
2811 /* Annotate start of buffers if we had overruns */
2812 if (ring_buffer_overruns(iter
->trace_buffer
->buffer
))
2813 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
2815 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
2816 if (trace_clocks
[trace_clock_id
].in_ns
)
2817 iter
->iter_flags
|= TRACE_FILE_TIME_IN_NS
;
2819 /* stop the trace while dumping if we are not opening "snapshot" */
2820 if (!iter
->snapshot
)
2821 tracing_stop_tr(tr
);
2823 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
) {
2824 for_each_tracing_cpu(cpu
) {
2825 iter
->buffer_iter
[cpu
] =
2826 ring_buffer_read_prepare(iter
->trace_buffer
->buffer
, cpu
);
2828 ring_buffer_read_prepare_sync();
2829 for_each_tracing_cpu(cpu
) {
2830 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2831 tracing_iter_reset(iter
, cpu
);
2834 cpu
= iter
->cpu_file
;
2835 iter
->buffer_iter
[cpu
] =
2836 ring_buffer_read_prepare(iter
->trace_buffer
->buffer
, cpu
);
2837 ring_buffer_read_prepare_sync();
2838 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2839 tracing_iter_reset(iter
, cpu
);
2844 mutex_unlock(&trace_types_lock
);
2849 mutex_unlock(&trace_types_lock
);
2851 kfree(iter
->buffer_iter
);
2853 seq_release_private(inode
, file
);
2854 return ERR_PTR(-ENOMEM
);
2857 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
2859 if (tracing_disabled
)
2862 filp
->private_data
= inode
->i_private
;
2866 static int tracing_release(struct inode
*inode
, struct file
*file
)
2868 struct seq_file
*m
= file
->private_data
;
2869 struct trace_iterator
*iter
;
2870 struct trace_array
*tr
;
2873 if (!(file
->f_mode
& FMODE_READ
))
2879 mutex_lock(&trace_types_lock
);
2884 for_each_tracing_cpu(cpu
) {
2885 if (iter
->buffer_iter
[cpu
])
2886 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
2889 if (iter
->trace
&& iter
->trace
->close
)
2890 iter
->trace
->close(iter
);
2892 if (!iter
->snapshot
)
2893 /* reenable tracing if it was previously enabled */
2894 tracing_start_tr(tr
);
2895 mutex_unlock(&trace_types_lock
);
2897 mutex_destroy(&iter
->mutex
);
2898 free_cpumask_var(iter
->started
);
2900 kfree(iter
->buffer_iter
);
2901 seq_release_private(inode
, file
);
2905 static int tracing_open(struct inode
*inode
, struct file
*file
)
2907 struct trace_iterator
*iter
;
2910 /* If this file was open for write, then erase contents */
2911 if ((file
->f_mode
& FMODE_WRITE
) &&
2912 (file
->f_flags
& O_TRUNC
)) {
2913 struct trace_cpu
*tc
= inode
->i_private
;
2914 struct trace_array
*tr
= tc
->tr
;
2916 if (tc
->cpu
== RING_BUFFER_ALL_CPUS
)
2917 tracing_reset_online_cpus(&tr
->trace_buffer
);
2919 tracing_reset(&tr
->trace_buffer
, tc
->cpu
);
2922 if (file
->f_mode
& FMODE_READ
) {
2923 iter
= __tracing_open(inode
, file
, false);
2925 ret
= PTR_ERR(iter
);
2926 else if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
2927 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
2933 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
2935 struct tracer
*t
= v
;
2945 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
2950 mutex_lock(&trace_types_lock
);
2951 for (t
= trace_types
; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
2957 static void t_stop(struct seq_file
*m
, void *p
)
2959 mutex_unlock(&trace_types_lock
);
2962 static int t_show(struct seq_file
*m
, void *v
)
2964 struct tracer
*t
= v
;
2969 seq_printf(m
, "%s", t
->name
);
2978 static const struct seq_operations show_traces_seq_ops
= {
2985 static int show_traces_open(struct inode
*inode
, struct file
*file
)
2987 if (tracing_disabled
)
2990 return seq_open(file
, &show_traces_seq_ops
);
2994 tracing_write_stub(struct file
*filp
, const char __user
*ubuf
,
2995 size_t count
, loff_t
*ppos
)
3000 static loff_t
tracing_seek(struct file
*file
, loff_t offset
, int origin
)
3002 if (file
->f_mode
& FMODE_READ
)
3003 return seq_lseek(file
, offset
, origin
);
3008 static const struct file_operations tracing_fops
= {
3009 .open
= tracing_open
,
3011 .write
= tracing_write_stub
,
3012 .llseek
= tracing_seek
,
3013 .release
= tracing_release
,
3016 static const struct file_operations show_traces_fops
= {
3017 .open
= show_traces_open
,
3019 .release
= seq_release
,
3020 .llseek
= seq_lseek
,
3024 * Only trace on a CPU if the bitmask is set:
3026 static cpumask_var_t tracing_cpumask
;
3029 * The tracer itself will not take this lock, but still we want
3030 * to provide a consistent cpumask to user-space:
3032 static DEFINE_MUTEX(tracing_cpumask_update_lock
);
3035 * Temporary storage for the character representation of the
3036 * CPU bitmask (and one more byte for the newline):
3038 static char mask_str
[NR_CPUS
+ 1];
3041 tracing_cpumask_read(struct file
*filp
, char __user
*ubuf
,
3042 size_t count
, loff_t
*ppos
)
3046 mutex_lock(&tracing_cpumask_update_lock
);
3048 len
= cpumask_scnprintf(mask_str
, count
, tracing_cpumask
);
3049 if (count
- len
< 2) {
3053 len
+= sprintf(mask_str
+ len
, "\n");
3054 count
= simple_read_from_buffer(ubuf
, count
, ppos
, mask_str
, NR_CPUS
+1);
3057 mutex_unlock(&tracing_cpumask_update_lock
);
3063 tracing_cpumask_write(struct file
*filp
, const char __user
*ubuf
,
3064 size_t count
, loff_t
*ppos
)
3066 struct trace_array
*tr
= filp
->private_data
;
3067 cpumask_var_t tracing_cpumask_new
;
3070 if (!alloc_cpumask_var(&tracing_cpumask_new
, GFP_KERNEL
))
3073 err
= cpumask_parse_user(ubuf
, count
, tracing_cpumask_new
);
3077 mutex_lock(&tracing_cpumask_update_lock
);
3079 local_irq_disable();
3080 arch_spin_lock(&ftrace_max_lock
);
3081 for_each_tracing_cpu(cpu
) {
3083 * Increase/decrease the disabled counter if we are
3084 * about to flip a bit in the cpumask:
3086 if (cpumask_test_cpu(cpu
, tracing_cpumask
) &&
3087 !cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
3088 atomic_inc(&per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->disabled
);
3089 ring_buffer_record_disable_cpu(tr
->trace_buffer
.buffer
, cpu
);
3091 if (!cpumask_test_cpu(cpu
, tracing_cpumask
) &&
3092 cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
3093 atomic_dec(&per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->disabled
);
3094 ring_buffer_record_enable_cpu(tr
->trace_buffer
.buffer
, cpu
);
3097 arch_spin_unlock(&ftrace_max_lock
);
3100 cpumask_copy(tracing_cpumask
, tracing_cpumask_new
);
3102 mutex_unlock(&tracing_cpumask_update_lock
);
3103 free_cpumask_var(tracing_cpumask_new
);
3108 free_cpumask_var(tracing_cpumask_new
);
3113 static const struct file_operations tracing_cpumask_fops
= {
3114 .open
= tracing_open_generic
,
3115 .read
= tracing_cpumask_read
,
3116 .write
= tracing_cpumask_write
,
3117 .llseek
= generic_file_llseek
,
3120 static int tracing_trace_options_show(struct seq_file
*m
, void *v
)
3122 struct tracer_opt
*trace_opts
;
3123 struct trace_array
*tr
= m
->private;
3127 mutex_lock(&trace_types_lock
);
3128 tracer_flags
= tr
->current_trace
->flags
->val
;
3129 trace_opts
= tr
->current_trace
->flags
->opts
;
3131 for (i
= 0; trace_options
[i
]; i
++) {
3132 if (trace_flags
& (1 << i
))
3133 seq_printf(m
, "%s\n", trace_options
[i
]);
3135 seq_printf(m
, "no%s\n", trace_options
[i
]);
3138 for (i
= 0; trace_opts
[i
].name
; i
++) {
3139 if (tracer_flags
& trace_opts
[i
].bit
)
3140 seq_printf(m
, "%s\n", trace_opts
[i
].name
);
3142 seq_printf(m
, "no%s\n", trace_opts
[i
].name
);
3144 mutex_unlock(&trace_types_lock
);
3149 static int __set_tracer_option(struct tracer
*trace
,
3150 struct tracer_flags
*tracer_flags
,
3151 struct tracer_opt
*opts
, int neg
)
3155 ret
= trace
->set_flag(tracer_flags
->val
, opts
->bit
, !neg
);
3160 tracer_flags
->val
&= ~opts
->bit
;
3162 tracer_flags
->val
|= opts
->bit
;
3166 /* Try to assign a tracer specific option */
3167 static int set_tracer_option(struct tracer
*trace
, char *cmp
, int neg
)
3169 struct tracer_flags
*tracer_flags
= trace
->flags
;
3170 struct tracer_opt
*opts
= NULL
;
3173 for (i
= 0; tracer_flags
->opts
[i
].name
; i
++) {
3174 opts
= &tracer_flags
->opts
[i
];
3176 if (strcmp(cmp
, opts
->name
) == 0)
3177 return __set_tracer_option(trace
, trace
->flags
,
3184 /* Some tracers require overwrite to stay enabled */
3185 int trace_keep_overwrite(struct tracer
*tracer
, u32 mask
, int set
)
3187 if (tracer
->enabled
&& (mask
& TRACE_ITER_OVERWRITE
) && !set
)
3193 int set_tracer_flag(struct trace_array
*tr
, unsigned int mask
, int enabled
)
3195 /* do nothing if flag is already set */
3196 if (!!(trace_flags
& mask
) == !!enabled
)
3199 /* Give the tracer a chance to approve the change */
3200 if (tr
->current_trace
->flag_changed
)
3201 if (tr
->current_trace
->flag_changed(tr
->current_trace
, mask
, !!enabled
))
3205 trace_flags
|= mask
;
3207 trace_flags
&= ~mask
;
3209 if (mask
== TRACE_ITER_RECORD_CMD
)
3210 trace_event_enable_cmd_record(enabled
);
3212 if (mask
== TRACE_ITER_OVERWRITE
) {
3213 ring_buffer_change_overwrite(tr
->trace_buffer
.buffer
, enabled
);
3214 #ifdef CONFIG_TRACER_MAX_TRACE
3215 ring_buffer_change_overwrite(tr
->max_buffer
.buffer
, enabled
);
3219 if (mask
== TRACE_ITER_PRINTK
)
3220 trace_printk_start_stop_comm(enabled
);
3225 static int trace_set_options(struct trace_array
*tr
, char *option
)
3232 cmp
= strstrip(option
);
3234 if (strncmp(cmp
, "no", 2) == 0) {
3239 mutex_lock(&trace_types_lock
);
3241 for (i
= 0; trace_options
[i
]; i
++) {
3242 if (strcmp(cmp
, trace_options
[i
]) == 0) {
3243 ret
= set_tracer_flag(tr
, 1 << i
, !neg
);
3248 /* If no option could be set, test the specific tracer options */
3249 if (!trace_options
[i
])
3250 ret
= set_tracer_option(tr
->current_trace
, cmp
, neg
);
3252 mutex_unlock(&trace_types_lock
);
3258 tracing_trace_options_write(struct file
*filp
, const char __user
*ubuf
,
3259 size_t cnt
, loff_t
*ppos
)
3261 struct seq_file
*m
= filp
->private_data
;
3262 struct trace_array
*tr
= m
->private;
3266 if (cnt
>= sizeof(buf
))
3269 if (copy_from_user(&buf
, ubuf
, cnt
))
3274 ret
= trace_set_options(tr
, buf
);
3283 static int tracing_trace_options_open(struct inode
*inode
, struct file
*file
)
3285 if (tracing_disabled
)
3288 return single_open(file
, tracing_trace_options_show
, inode
->i_private
);
3291 static const struct file_operations tracing_iter_fops
= {
3292 .open
= tracing_trace_options_open
,
3294 .llseek
= seq_lseek
,
3295 .release
= single_release
,
3296 .write
= tracing_trace_options_write
,
3299 static const char readme_msg
[] =
3300 "tracing mini-HOWTO:\n\n"
3301 "# mount -t debugfs nodev /sys/kernel/debug\n\n"
3302 "# cat /sys/kernel/debug/tracing/available_tracers\n"
3303 "wakeup wakeup_rt preemptirqsoff preemptoff irqsoff function nop\n\n"
3304 "# cat /sys/kernel/debug/tracing/current_tracer\n"
3306 "# echo wakeup > /sys/kernel/debug/tracing/current_tracer\n"
3307 "# cat /sys/kernel/debug/tracing/current_tracer\n"
3309 "# cat /sys/kernel/debug/tracing/trace_options\n"
3310 "noprint-parent nosym-offset nosym-addr noverbose\n"
3311 "# echo print-parent > /sys/kernel/debug/tracing/trace_options\n"
3312 "# echo 1 > /sys/kernel/debug/tracing/tracing_on\n"
3313 "# cat /sys/kernel/debug/tracing/trace > /tmp/trace.txt\n"
3314 "# echo 0 > /sys/kernel/debug/tracing/tracing_on\n"
3318 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
3319 size_t cnt
, loff_t
*ppos
)
3321 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
3322 readme_msg
, strlen(readme_msg
));
3325 static const struct file_operations tracing_readme_fops
= {
3326 .open
= tracing_open_generic
,
3327 .read
= tracing_readme_read
,
3328 .llseek
= generic_file_llseek
,
3332 tracing_saved_cmdlines_read(struct file
*file
, char __user
*ubuf
,
3333 size_t cnt
, loff_t
*ppos
)
3342 file_buf
= kmalloc(SAVED_CMDLINES
*(16+TASK_COMM_LEN
), GFP_KERNEL
);
3346 buf_comm
= kmalloc(TASK_COMM_LEN
, GFP_KERNEL
);
3354 for (i
= 0; i
< SAVED_CMDLINES
; i
++) {
3357 pid
= map_cmdline_to_pid
[i
];
3358 if (pid
== -1 || pid
== NO_CMDLINE_MAP
)
3361 trace_find_cmdline(pid
, buf_comm
);
3362 r
= sprintf(buf
, "%d %s\n", pid
, buf_comm
);
3367 len
= simple_read_from_buffer(ubuf
, cnt
, ppos
,
3376 static const struct file_operations tracing_saved_cmdlines_fops
= {
3377 .open
= tracing_open_generic
,
3378 .read
= tracing_saved_cmdlines_read
,
3379 .llseek
= generic_file_llseek
,
3383 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
3384 size_t cnt
, loff_t
*ppos
)
3386 struct trace_array
*tr
= filp
->private_data
;
3387 char buf
[MAX_TRACER_SIZE
+2];
3390 mutex_lock(&trace_types_lock
);
3391 r
= sprintf(buf
, "%s\n", tr
->current_trace
->name
);
3392 mutex_unlock(&trace_types_lock
);
3394 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3397 int tracer_init(struct tracer
*t
, struct trace_array
*tr
)
3399 tracing_reset_online_cpus(&tr
->trace_buffer
);
3403 static void set_buffer_entries(struct trace_buffer
*buf
, unsigned long val
)
3407 for_each_tracing_cpu(cpu
)
3408 per_cpu_ptr(buf
->data
, cpu
)->entries
= val
;
3411 #ifdef CONFIG_TRACER_MAX_TRACE
3412 /* resize @tr's buffer to the size of @size_tr's entries */
3413 static int resize_buffer_duplicate_size(struct trace_buffer
*trace_buf
,
3414 struct trace_buffer
*size_buf
, int cpu_id
)
3418 if (cpu_id
== RING_BUFFER_ALL_CPUS
) {
3419 for_each_tracing_cpu(cpu
) {
3420 ret
= ring_buffer_resize(trace_buf
->buffer
,
3421 per_cpu_ptr(size_buf
->data
, cpu
)->entries
, cpu
);
3424 per_cpu_ptr(trace_buf
->data
, cpu
)->entries
=
3425 per_cpu_ptr(size_buf
->data
, cpu
)->entries
;
3428 ret
= ring_buffer_resize(trace_buf
->buffer
,
3429 per_cpu_ptr(size_buf
->data
, cpu_id
)->entries
, cpu_id
);
3431 per_cpu_ptr(trace_buf
->data
, cpu_id
)->entries
=
3432 per_cpu_ptr(size_buf
->data
, cpu_id
)->entries
;
3437 #endif /* CONFIG_TRACER_MAX_TRACE */
3439 static int __tracing_resize_ring_buffer(struct trace_array
*tr
,
3440 unsigned long size
, int cpu
)
3445 * If kernel or user changes the size of the ring buffer
3446 * we use the size that was given, and we can forget about
3447 * expanding it later.
3449 ring_buffer_expanded
= true;
3451 /* May be called before buffers are initialized */
3452 if (!tr
->trace_buffer
.buffer
)
3455 ret
= ring_buffer_resize(tr
->trace_buffer
.buffer
, size
, cpu
);
3459 #ifdef CONFIG_TRACER_MAX_TRACE
3460 if (!(tr
->flags
& TRACE_ARRAY_FL_GLOBAL
) ||
3461 !tr
->current_trace
->use_max_tr
)
3464 ret
= ring_buffer_resize(tr
->max_buffer
.buffer
, size
, cpu
);
3466 int r
= resize_buffer_duplicate_size(&tr
->trace_buffer
,
3467 &tr
->trace_buffer
, cpu
);
3470 * AARGH! We are left with different
3471 * size max buffer!!!!
3472 * The max buffer is our "snapshot" buffer.
3473 * When a tracer needs a snapshot (one of the
3474 * latency tracers), it swaps the max buffer
3475 * with the saved snap shot. We succeeded to
3476 * update the size of the main buffer, but failed to
3477 * update the size of the max buffer. But when we tried
3478 * to reset the main buffer to the original size, we
3479 * failed there too. This is very unlikely to
3480 * happen, but if it does, warn and kill all
3484 tracing_disabled
= 1;
3489 if (cpu
== RING_BUFFER_ALL_CPUS
)
3490 set_buffer_entries(&tr
->max_buffer
, size
);
3492 per_cpu_ptr(tr
->max_buffer
.data
, cpu
)->entries
= size
;
3495 #endif /* CONFIG_TRACER_MAX_TRACE */
3497 if (cpu
== RING_BUFFER_ALL_CPUS
)
3498 set_buffer_entries(&tr
->trace_buffer
, size
);
3500 per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
= size
;
3505 static ssize_t
tracing_resize_ring_buffer(struct trace_array
*tr
,
3506 unsigned long size
, int cpu_id
)
3510 mutex_lock(&trace_types_lock
);
3512 if (cpu_id
!= RING_BUFFER_ALL_CPUS
) {
3513 /* make sure, this cpu is enabled in the mask */
3514 if (!cpumask_test_cpu(cpu_id
, tracing_buffer_mask
)) {
3520 ret
= __tracing_resize_ring_buffer(tr
, size
, cpu_id
);
3525 mutex_unlock(&trace_types_lock
);
3532 * tracing_update_buffers - used by tracing facility to expand ring buffers
3534 * To save on memory when the tracing is never used on a system with it
3535 * configured in. The ring buffers are set to a minimum size. But once
3536 * a user starts to use the tracing facility, then they need to grow
3537 * to their default size.
3539 * This function is to be called when a tracer is about to be used.
3541 int tracing_update_buffers(void)
3545 mutex_lock(&trace_types_lock
);
3546 if (!ring_buffer_expanded
)
3547 ret
= __tracing_resize_ring_buffer(&global_trace
, trace_buf_size
,
3548 RING_BUFFER_ALL_CPUS
);
3549 mutex_unlock(&trace_types_lock
);
3554 struct trace_option_dentry
;
3556 static struct trace_option_dentry
*
3557 create_trace_option_files(struct trace_array
*tr
, struct tracer
*tracer
);
3560 destroy_trace_option_files(struct trace_option_dentry
*topts
);
3562 static int tracing_set_tracer(const char *buf
)
3564 static struct trace_option_dentry
*topts
;
3565 struct trace_array
*tr
= &global_trace
;
3567 #ifdef CONFIG_TRACER_MAX_TRACE
3572 mutex_lock(&trace_types_lock
);
3574 if (!ring_buffer_expanded
) {
3575 ret
= __tracing_resize_ring_buffer(tr
, trace_buf_size
,
3576 RING_BUFFER_ALL_CPUS
);
3582 for (t
= trace_types
; t
; t
= t
->next
) {
3583 if (strcmp(t
->name
, buf
) == 0)
3590 if (t
== tr
->current_trace
)
3593 trace_branch_disable();
3595 tr
->current_trace
->enabled
= false;
3597 if (tr
->current_trace
->reset
)
3598 tr
->current_trace
->reset(tr
);
3600 /* Current trace needs to be nop_trace before synchronize_sched */
3601 tr
->current_trace
= &nop_trace
;
3603 #ifdef CONFIG_TRACER_MAX_TRACE
3604 had_max_tr
= tr
->allocated_snapshot
;
3606 if (had_max_tr
&& !t
->use_max_tr
) {
3608 * We need to make sure that the update_max_tr sees that
3609 * current_trace changed to nop_trace to keep it from
3610 * swapping the buffers after we resize it.
3611 * The update_max_tr is called from interrupts disabled
3612 * so a synchronized_sched() is sufficient.
3614 synchronize_sched();
3618 destroy_trace_option_files(topts
);
3620 topts
= create_trace_option_files(tr
, t
);
3622 #ifdef CONFIG_TRACER_MAX_TRACE
3623 if (t
->use_max_tr
&& !had_max_tr
) {
3624 ret
= alloc_snapshot(tr
);
3631 ret
= tracer_init(t
, tr
);
3636 tr
->current_trace
= t
;
3637 tr
->current_trace
->enabled
= true;
3638 trace_branch_enable(tr
);
3640 mutex_unlock(&trace_types_lock
);
3646 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
3647 size_t cnt
, loff_t
*ppos
)
3649 char buf
[MAX_TRACER_SIZE
+1];
3656 if (cnt
> MAX_TRACER_SIZE
)
3657 cnt
= MAX_TRACER_SIZE
;
3659 if (copy_from_user(&buf
, ubuf
, cnt
))
3664 /* strip ending whitespace. */
3665 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
3668 err
= tracing_set_tracer(buf
);
3678 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
3679 size_t cnt
, loff_t
*ppos
)
3681 unsigned long *ptr
= filp
->private_data
;
3685 r
= snprintf(buf
, sizeof(buf
), "%ld\n",
3686 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
3687 if (r
> sizeof(buf
))
3689 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3693 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
3694 size_t cnt
, loff_t
*ppos
)
3696 unsigned long *ptr
= filp
->private_data
;
3700 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
3709 static int tracing_open_pipe(struct inode
*inode
, struct file
*filp
)
3711 struct trace_cpu
*tc
= inode
->i_private
;
3712 struct trace_array
*tr
= tc
->tr
;
3713 struct trace_iterator
*iter
;
3716 if (tracing_disabled
)
3719 mutex_lock(&trace_types_lock
);
3721 /* create a buffer to store the information to pass to userspace */
3722 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
3729 * We make a copy of the current tracer to avoid concurrent
3730 * changes on it while we are reading.
3732 iter
->trace
= kmalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
3737 *iter
->trace
= *tr
->current_trace
;
3739 if (!alloc_cpumask_var(&iter
->started
, GFP_KERNEL
)) {
3744 /* trace pipe does not show start of buffer */
3745 cpumask_setall(iter
->started
);
3747 if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
3748 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
3750 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
3751 if (trace_clocks
[trace_clock_id
].in_ns
)
3752 iter
->iter_flags
|= TRACE_FILE_TIME_IN_NS
;
3754 iter
->cpu_file
= tc
->cpu
;
3756 iter
->trace_buffer
= &tc
->tr
->trace_buffer
;
3757 mutex_init(&iter
->mutex
);
3758 filp
->private_data
= iter
;
3760 if (iter
->trace
->pipe_open
)
3761 iter
->trace
->pipe_open(iter
);
3763 nonseekable_open(inode
, filp
);
3765 mutex_unlock(&trace_types_lock
);
3771 mutex_unlock(&trace_types_lock
);
3775 static int tracing_release_pipe(struct inode
*inode
, struct file
*file
)
3777 struct trace_iterator
*iter
= file
->private_data
;
3779 mutex_lock(&trace_types_lock
);
3781 if (iter
->trace
->pipe_close
)
3782 iter
->trace
->pipe_close(iter
);
3784 mutex_unlock(&trace_types_lock
);
3786 free_cpumask_var(iter
->started
);
3787 mutex_destroy(&iter
->mutex
);
3795 trace_poll(struct trace_iterator
*iter
, struct file
*filp
, poll_table
*poll_table
)
3797 /* Iterators are static, they should be filled or empty */
3798 if (trace_buffer_iter(iter
, iter
->cpu_file
))
3799 return POLLIN
| POLLRDNORM
;
3801 if (trace_flags
& TRACE_ITER_BLOCK
)
3803 * Always select as readable when in blocking mode
3805 return POLLIN
| POLLRDNORM
;
3807 return ring_buffer_poll_wait(iter
->trace_buffer
->buffer
, iter
->cpu_file
,
3812 tracing_poll_pipe(struct file
*filp
, poll_table
*poll_table
)
3814 struct trace_iterator
*iter
= filp
->private_data
;
3816 return trace_poll(iter
, filp
, poll_table
);
3820 * This is a make-shift waitqueue.
3821 * A tracer might use this callback on some rare cases:
3823 * 1) the current tracer might hold the runqueue lock when it wakes up
3824 * a reader, hence a deadlock (sched, function, and function graph tracers)
3825 * 2) the function tracers, trace all functions, we don't want
3826 * the overhead of calling wake_up and friends
3827 * (and tracing them too)
3829 * Anyway, this is really very primitive wakeup.
3831 void poll_wait_pipe(struct trace_iterator
*iter
)
3833 set_current_state(TASK_INTERRUPTIBLE
);
3834 /* sleep for 100 msecs, and try again. */
3835 schedule_timeout(HZ
/ 10);
3838 /* Must be called with trace_types_lock mutex held. */
3839 static int tracing_wait_pipe(struct file
*filp
)
3841 struct trace_iterator
*iter
= filp
->private_data
;
3843 while (trace_empty(iter
)) {
3845 if ((filp
->f_flags
& O_NONBLOCK
)) {
3849 mutex_unlock(&iter
->mutex
);
3851 iter
->trace
->wait_pipe(iter
);
3853 mutex_lock(&iter
->mutex
);
3855 if (signal_pending(current
))
3859 * We block until we read something and tracing is disabled.
3860 * We still block if tracing is disabled, but we have never
3861 * read anything. This allows a user to cat this file, and
3862 * then enable tracing. But after we have read something,
3863 * we give an EOF when tracing is again disabled.
3865 * iter->pos will be 0 if we haven't read anything.
3867 if (!tracing_is_enabled() && iter
->pos
)
3878 tracing_read_pipe(struct file
*filp
, char __user
*ubuf
,
3879 size_t cnt
, loff_t
*ppos
)
3881 struct trace_iterator
*iter
= filp
->private_data
;
3882 struct trace_array
*tr
= iter
->tr
;
3885 /* return any leftover data */
3886 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
3890 trace_seq_init(&iter
->seq
);
3892 /* copy the tracer to avoid using a global lock all around */
3893 mutex_lock(&trace_types_lock
);
3894 if (unlikely(iter
->trace
->name
!= tr
->current_trace
->name
))
3895 *iter
->trace
= *tr
->current_trace
;
3896 mutex_unlock(&trace_types_lock
);
3899 * Avoid more than one consumer on a single file descriptor
3900 * This is just a matter of traces coherency, the ring buffer itself
3903 mutex_lock(&iter
->mutex
);
3904 if (iter
->trace
->read
) {
3905 sret
= iter
->trace
->read(iter
, filp
, ubuf
, cnt
, ppos
);
3911 sret
= tracing_wait_pipe(filp
);
3915 /* stop when tracing is finished */
3916 if (trace_empty(iter
)) {
3921 if (cnt
>= PAGE_SIZE
)
3922 cnt
= PAGE_SIZE
- 1;
3924 /* reset all but tr, trace, and overruns */
3925 memset(&iter
->seq
, 0,
3926 sizeof(struct trace_iterator
) -
3927 offsetof(struct trace_iterator
, seq
));
3930 trace_event_read_lock();
3931 trace_access_lock(iter
->cpu_file
);
3932 while (trace_find_next_entry_inc(iter
) != NULL
) {
3933 enum print_line_t ret
;
3934 int len
= iter
->seq
.len
;
3936 ret
= print_trace_line(iter
);
3937 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
3938 /* don't print partial lines */
3939 iter
->seq
.len
= len
;
3942 if (ret
!= TRACE_TYPE_NO_CONSUME
)
3943 trace_consume(iter
);
3945 if (iter
->seq
.len
>= cnt
)
3949 * Setting the full flag means we reached the trace_seq buffer
3950 * size and we should leave by partial output condition above.
3951 * One of the trace_seq_* functions is not used properly.
3953 WARN_ONCE(iter
->seq
.full
, "full flag set for trace type %d",
3956 trace_access_unlock(iter
->cpu_file
);
3957 trace_event_read_unlock();
3959 /* Now copy what we have to the user */
3960 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
3961 if (iter
->seq
.readpos
>= iter
->seq
.len
)
3962 trace_seq_init(&iter
->seq
);
3965 * If there was nothing to send to user, in spite of consuming trace
3966 * entries, go back to wait for more entries.
3972 mutex_unlock(&iter
->mutex
);
3977 static void tracing_pipe_buf_release(struct pipe_inode_info
*pipe
,
3978 struct pipe_buffer
*buf
)
3980 __free_page(buf
->page
);
3983 static void tracing_spd_release_pipe(struct splice_pipe_desc
*spd
,
3986 __free_page(spd
->pages
[idx
]);
3989 static const struct pipe_buf_operations tracing_pipe_buf_ops
= {
3991 .map
= generic_pipe_buf_map
,
3992 .unmap
= generic_pipe_buf_unmap
,
3993 .confirm
= generic_pipe_buf_confirm
,
3994 .release
= tracing_pipe_buf_release
,
3995 .steal
= generic_pipe_buf_steal
,
3996 .get
= generic_pipe_buf_get
,
4000 tracing_fill_pipe_page(size_t rem
, struct trace_iterator
*iter
)
4005 /* Seq buffer is page-sized, exactly what we need. */
4007 count
= iter
->seq
.len
;
4008 ret
= print_trace_line(iter
);
4009 count
= iter
->seq
.len
- count
;
4012 iter
->seq
.len
-= count
;
4015 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
4016 iter
->seq
.len
-= count
;
4020 if (ret
!= TRACE_TYPE_NO_CONSUME
)
4021 trace_consume(iter
);
4023 if (!trace_find_next_entry_inc(iter
)) {
4033 static ssize_t
tracing_splice_read_pipe(struct file
*filp
,
4035 struct pipe_inode_info
*pipe
,
4039 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
4040 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
4041 struct trace_iterator
*iter
= filp
->private_data
;
4042 struct splice_pipe_desc spd
= {
4044 .partial
= partial_def
,
4045 .nr_pages
= 0, /* This gets updated below. */
4046 .nr_pages_max
= PIPE_DEF_BUFFERS
,
4048 .ops
= &tracing_pipe_buf_ops
,
4049 .spd_release
= tracing_spd_release_pipe
,
4051 struct trace_array
*tr
= iter
->tr
;
4056 if (splice_grow_spd(pipe
, &spd
))
4059 /* copy the tracer to avoid using a global lock all around */
4060 mutex_lock(&trace_types_lock
);
4061 if (unlikely(iter
->trace
->name
!= tr
->current_trace
->name
))
4062 *iter
->trace
= *tr
->current_trace
;
4063 mutex_unlock(&trace_types_lock
);
4065 mutex_lock(&iter
->mutex
);
4067 if (iter
->trace
->splice_read
) {
4068 ret
= iter
->trace
->splice_read(iter
, filp
,
4069 ppos
, pipe
, len
, flags
);
4074 ret
= tracing_wait_pipe(filp
);
4078 if (!iter
->ent
&& !trace_find_next_entry_inc(iter
)) {
4083 trace_event_read_lock();
4084 trace_access_lock(iter
->cpu_file
);
4086 /* Fill as many pages as possible. */
4087 for (i
= 0, rem
= len
; i
< pipe
->buffers
&& rem
; i
++) {
4088 spd
.pages
[i
] = alloc_page(GFP_KERNEL
);
4092 rem
= tracing_fill_pipe_page(rem
, iter
);
4094 /* Copy the data into the page, so we can start over. */
4095 ret
= trace_seq_to_buffer(&iter
->seq
,
4096 page_address(spd
.pages
[i
]),
4099 __free_page(spd
.pages
[i
]);
4102 spd
.partial
[i
].offset
= 0;
4103 spd
.partial
[i
].len
= iter
->seq
.len
;
4105 trace_seq_init(&iter
->seq
);
4108 trace_access_unlock(iter
->cpu_file
);
4109 trace_event_read_unlock();
4110 mutex_unlock(&iter
->mutex
);
4114 ret
= splice_to_pipe(pipe
, &spd
);
4116 splice_shrink_spd(&spd
);
4120 mutex_unlock(&iter
->mutex
);
4125 tracing_entries_read(struct file
*filp
, char __user
*ubuf
,
4126 size_t cnt
, loff_t
*ppos
)
4128 struct trace_cpu
*tc
= filp
->private_data
;
4129 struct trace_array
*tr
= tc
->tr
;
4134 mutex_lock(&trace_types_lock
);
4136 if (tc
->cpu
== RING_BUFFER_ALL_CPUS
) {
4137 int cpu
, buf_size_same
;
4142 /* check if all cpu sizes are same */
4143 for_each_tracing_cpu(cpu
) {
4144 /* fill in the size from first enabled cpu */
4146 size
= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
;
4147 if (size
!= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
) {
4153 if (buf_size_same
) {
4154 if (!ring_buffer_expanded
)
4155 r
= sprintf(buf
, "%lu (expanded: %lu)\n",
4157 trace_buf_size
>> 10);
4159 r
= sprintf(buf
, "%lu\n", size
>> 10);
4161 r
= sprintf(buf
, "X\n");
4163 r
= sprintf(buf
, "%lu\n", per_cpu_ptr(tr
->trace_buffer
.data
, tc
->cpu
)->entries
>> 10);
4165 mutex_unlock(&trace_types_lock
);
4167 ret
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
4172 tracing_entries_write(struct file
*filp
, const char __user
*ubuf
,
4173 size_t cnt
, loff_t
*ppos
)
4175 struct trace_cpu
*tc
= filp
->private_data
;
4179 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
4183 /* must have at least 1 entry */
4187 /* value is in KB */
4190 ret
= tracing_resize_ring_buffer(tc
->tr
, val
, tc
->cpu
);
4200 tracing_total_entries_read(struct file
*filp
, char __user
*ubuf
,
4201 size_t cnt
, loff_t
*ppos
)
4203 struct trace_array
*tr
= filp
->private_data
;
4206 unsigned long size
= 0, expanded_size
= 0;
4208 mutex_lock(&trace_types_lock
);
4209 for_each_tracing_cpu(cpu
) {
4210 size
+= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
>> 10;
4211 if (!ring_buffer_expanded
)
4212 expanded_size
+= trace_buf_size
>> 10;
4214 if (ring_buffer_expanded
)
4215 r
= sprintf(buf
, "%lu\n", size
);
4217 r
= sprintf(buf
, "%lu (expanded: %lu)\n", size
, expanded_size
);
4218 mutex_unlock(&trace_types_lock
);
4220 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
4224 tracing_free_buffer_write(struct file
*filp
, const char __user
*ubuf
,
4225 size_t cnt
, loff_t
*ppos
)
4228 * There is no need to read what the user has written, this function
4229 * is just to make sure that there is no error when "echo" is used
4238 tracing_free_buffer_release(struct inode
*inode
, struct file
*filp
)
4240 struct trace_array
*tr
= inode
->i_private
;
4242 /* disable tracing ? */
4243 if (trace_flags
& TRACE_ITER_STOP_ON_FREE
)
4245 /* resize the ring buffer to 0 */
4246 tracing_resize_ring_buffer(tr
, 0, RING_BUFFER_ALL_CPUS
);
4252 tracing_mark_write(struct file
*filp
, const char __user
*ubuf
,
4253 size_t cnt
, loff_t
*fpos
)
4255 unsigned long addr
= (unsigned long)ubuf
;
4256 struct ring_buffer_event
*event
;
4257 struct ring_buffer
*buffer
;
4258 struct print_entry
*entry
;
4259 unsigned long irq_flags
;
4260 struct page
*pages
[2];
4270 if (tracing_disabled
)
4273 if (!(trace_flags
& TRACE_ITER_MARKERS
))
4276 if (cnt
> TRACE_BUF_SIZE
)
4277 cnt
= TRACE_BUF_SIZE
;
4280 * Userspace is injecting traces into the kernel trace buffer.
4281 * We want to be as non intrusive as possible.
4282 * To do so, we do not want to allocate any special buffers
4283 * or take any locks, but instead write the userspace data
4284 * straight into the ring buffer.
4286 * First we need to pin the userspace buffer into memory,
4287 * which, most likely it is, because it just referenced it.
4288 * But there's no guarantee that it is. By using get_user_pages_fast()
4289 * and kmap_atomic/kunmap_atomic() we can get access to the
4290 * pages directly. We then write the data directly into the
4293 BUILD_BUG_ON(TRACE_BUF_SIZE
>= PAGE_SIZE
);
4295 /* check if we cross pages */
4296 if ((addr
& PAGE_MASK
) != ((addr
+ cnt
) & PAGE_MASK
))
4299 offset
= addr
& (PAGE_SIZE
- 1);
4302 ret
= get_user_pages_fast(addr
, nr_pages
, 0, pages
);
4303 if (ret
< nr_pages
) {
4305 put_page(pages
[ret
]);
4310 for (i
= 0; i
< nr_pages
; i
++)
4311 map_page
[i
] = kmap_atomic(pages
[i
]);
4313 local_save_flags(irq_flags
);
4314 size
= sizeof(*entry
) + cnt
+ 2; /* possible \n added */
4315 buffer
= global_trace
.trace_buffer
.buffer
;
4316 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, size
,
4317 irq_flags
, preempt_count());
4319 /* Ring buffer disabled, return as if not open for write */
4324 entry
= ring_buffer_event_data(event
);
4325 entry
->ip
= _THIS_IP_
;
4327 if (nr_pages
== 2) {
4328 len
= PAGE_SIZE
- offset
;
4329 memcpy(&entry
->buf
, map_page
[0] + offset
, len
);
4330 memcpy(&entry
->buf
[len
], map_page
[1], cnt
- len
);
4332 memcpy(&entry
->buf
, map_page
[0] + offset
, cnt
);
4334 if (entry
->buf
[cnt
- 1] != '\n') {
4335 entry
->buf
[cnt
] = '\n';
4336 entry
->buf
[cnt
+ 1] = '\0';
4338 entry
->buf
[cnt
] = '\0';
4340 __buffer_unlock_commit(buffer
, event
);
4347 for (i
= 0; i
< nr_pages
; i
++){
4348 kunmap_atomic(map_page
[i
]);
4355 static int tracing_clock_show(struct seq_file
*m
, void *v
)
4357 struct trace_array
*tr
= m
->private;
4360 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++)
4362 "%s%s%s%s", i
? " " : "",
4363 i
== tr
->clock_id
? "[" : "", trace_clocks
[i
].name
,
4364 i
== tr
->clock_id
? "]" : "");
4370 static ssize_t
tracing_clock_write(struct file
*filp
, const char __user
*ubuf
,
4371 size_t cnt
, loff_t
*fpos
)
4373 struct seq_file
*m
= filp
->private_data
;
4374 struct trace_array
*tr
= m
->private;
4376 const char *clockstr
;
4379 if (cnt
>= sizeof(buf
))
4382 if (copy_from_user(&buf
, ubuf
, cnt
))
4387 clockstr
= strstrip(buf
);
4389 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++) {
4390 if (strcmp(trace_clocks
[i
].name
, clockstr
) == 0)
4393 if (i
== ARRAY_SIZE(trace_clocks
))
4396 mutex_lock(&trace_types_lock
);
4400 ring_buffer_set_clock(tr
->trace_buffer
.buffer
, trace_clocks
[i
].func
);
4403 * New clock may not be consistent with the previous clock.
4404 * Reset the buffer so that it doesn't have incomparable timestamps.
4406 tracing_reset_online_cpus(&global_trace
.trace_buffer
);
4408 #ifdef CONFIG_TRACER_MAX_TRACE
4409 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
&& tr
->max_buffer
.buffer
)
4410 ring_buffer_set_clock(tr
->max_buffer
.buffer
, trace_clocks
[i
].func
);
4411 tracing_reset_online_cpus(&global_trace
.max_buffer
);
4414 mutex_unlock(&trace_types_lock
);
4421 static int tracing_clock_open(struct inode
*inode
, struct file
*file
)
4423 if (tracing_disabled
)
4426 return single_open(file
, tracing_clock_show
, inode
->i_private
);
4429 struct ftrace_buffer_info
{
4430 struct trace_iterator iter
;
4435 #ifdef CONFIG_TRACER_SNAPSHOT
4436 static int tracing_snapshot_open(struct inode
*inode
, struct file
*file
)
4438 struct trace_cpu
*tc
= inode
->i_private
;
4439 struct trace_iterator
*iter
;
4443 if (file
->f_mode
& FMODE_READ
) {
4444 iter
= __tracing_open(inode
, file
, true);
4446 ret
= PTR_ERR(iter
);
4448 /* Writes still need the seq_file to hold the private data */
4449 m
= kzalloc(sizeof(*m
), GFP_KERNEL
);
4452 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
4458 iter
->trace_buffer
= &tc
->tr
->max_buffer
;
4459 iter
->cpu_file
= tc
->cpu
;
4461 file
->private_data
= m
;
4468 tracing_snapshot_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
4471 struct seq_file
*m
= filp
->private_data
;
4472 struct trace_iterator
*iter
= m
->private;
4473 struct trace_array
*tr
= iter
->tr
;
4477 ret
= tracing_update_buffers();
4481 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
4485 mutex_lock(&trace_types_lock
);
4487 if (tr
->current_trace
->use_max_tr
) {
4494 if (iter
->cpu_file
!= RING_BUFFER_ALL_CPUS
) {
4498 if (tr
->allocated_snapshot
)
4502 /* Only allow per-cpu swap if the ring buffer supports it */
4503 #ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
4504 if (iter
->cpu_file
!= RING_BUFFER_ALL_CPUS
) {
4509 if (!tr
->allocated_snapshot
) {
4510 ret
= alloc_snapshot(tr
);
4514 local_irq_disable();
4515 /* Now, we're going to swap */
4516 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
)
4517 update_max_tr(tr
, current
, smp_processor_id());
4519 update_max_tr_single(tr
, current
, iter
->cpu_file
);
4523 if (tr
->allocated_snapshot
) {
4524 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
)
4525 tracing_reset_online_cpus(&tr
->max_buffer
);
4527 tracing_reset(&tr
->max_buffer
, iter
->cpu_file
);
4537 mutex_unlock(&trace_types_lock
);
4541 static int tracing_snapshot_release(struct inode
*inode
, struct file
*file
)
4543 struct seq_file
*m
= file
->private_data
;
4545 if (file
->f_mode
& FMODE_READ
)
4546 return tracing_release(inode
, file
);
4548 /* If write only, the seq_file is just a stub */
4556 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
);
4557 static ssize_t
tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
4558 size_t count
, loff_t
*ppos
);
4559 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
);
4560 static ssize_t
tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
4561 struct pipe_inode_info
*pipe
, size_t len
, unsigned int flags
);
4563 static int snapshot_raw_open(struct inode
*inode
, struct file
*filp
)
4565 struct ftrace_buffer_info
*info
;
4568 ret
= tracing_buffers_open(inode
, filp
);
4572 info
= filp
->private_data
;
4574 if (info
->iter
.trace
->use_max_tr
) {
4575 tracing_buffers_release(inode
, filp
);
4579 info
->iter
.snapshot
= true;
4580 info
->iter
.trace_buffer
= &info
->iter
.tr
->max_buffer
;
4585 #endif /* CONFIG_TRACER_SNAPSHOT */
4588 static const struct file_operations tracing_max_lat_fops
= {
4589 .open
= tracing_open_generic
,
4590 .read
= tracing_max_lat_read
,
4591 .write
= tracing_max_lat_write
,
4592 .llseek
= generic_file_llseek
,
4595 static const struct file_operations set_tracer_fops
= {
4596 .open
= tracing_open_generic
,
4597 .read
= tracing_set_trace_read
,
4598 .write
= tracing_set_trace_write
,
4599 .llseek
= generic_file_llseek
,
4602 static const struct file_operations tracing_pipe_fops
= {
4603 .open
= tracing_open_pipe
,
4604 .poll
= tracing_poll_pipe
,
4605 .read
= tracing_read_pipe
,
4606 .splice_read
= tracing_splice_read_pipe
,
4607 .release
= tracing_release_pipe
,
4608 .llseek
= no_llseek
,
4611 static const struct file_operations tracing_entries_fops
= {
4612 .open
= tracing_open_generic
,
4613 .read
= tracing_entries_read
,
4614 .write
= tracing_entries_write
,
4615 .llseek
= generic_file_llseek
,
4618 static const struct file_operations tracing_total_entries_fops
= {
4619 .open
= tracing_open_generic
,
4620 .read
= tracing_total_entries_read
,
4621 .llseek
= generic_file_llseek
,
4624 static const struct file_operations tracing_free_buffer_fops
= {
4625 .write
= tracing_free_buffer_write
,
4626 .release
= tracing_free_buffer_release
,
4629 static const struct file_operations tracing_mark_fops
= {
4630 .open
= tracing_open_generic
,
4631 .write
= tracing_mark_write
,
4632 .llseek
= generic_file_llseek
,
4635 static const struct file_operations trace_clock_fops
= {
4636 .open
= tracing_clock_open
,
4638 .llseek
= seq_lseek
,
4639 .release
= single_release
,
4640 .write
= tracing_clock_write
,
4643 #ifdef CONFIG_TRACER_SNAPSHOT
4644 static const struct file_operations snapshot_fops
= {
4645 .open
= tracing_snapshot_open
,
4647 .write
= tracing_snapshot_write
,
4648 .llseek
= tracing_seek
,
4649 .release
= tracing_snapshot_release
,
4652 static const struct file_operations snapshot_raw_fops
= {
4653 .open
= snapshot_raw_open
,
4654 .read
= tracing_buffers_read
,
4655 .release
= tracing_buffers_release
,
4656 .splice_read
= tracing_buffers_splice_read
,
4657 .llseek
= no_llseek
,
4660 #endif /* CONFIG_TRACER_SNAPSHOT */
4662 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
)
4664 struct trace_cpu
*tc
= inode
->i_private
;
4665 struct trace_array
*tr
= tc
->tr
;
4666 struct ftrace_buffer_info
*info
;
4668 if (tracing_disabled
)
4671 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
4675 mutex_lock(&trace_types_lock
);
4680 info
->iter
.cpu_file
= tc
->cpu
;
4681 info
->iter
.trace
= tr
->current_trace
;
4682 info
->iter
.trace_buffer
= &tr
->trace_buffer
;
4684 /* Force reading ring buffer for first read */
4685 info
->read
= (unsigned int)-1;
4687 filp
->private_data
= info
;
4689 mutex_unlock(&trace_types_lock
);
4691 return nonseekable_open(inode
, filp
);
4695 tracing_buffers_poll(struct file
*filp
, poll_table
*poll_table
)
4697 struct ftrace_buffer_info
*info
= filp
->private_data
;
4698 struct trace_iterator
*iter
= &info
->iter
;
4700 return trace_poll(iter
, filp
, poll_table
);
4704 tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
4705 size_t count
, loff_t
*ppos
)
4707 struct ftrace_buffer_info
*info
= filp
->private_data
;
4708 struct trace_iterator
*iter
= &info
->iter
;
4715 mutex_lock(&trace_types_lock
);
4717 #ifdef CONFIG_TRACER_MAX_TRACE
4718 if (iter
->snapshot
&& iter
->tr
->current_trace
->use_max_tr
) {
4725 info
->spare
= ring_buffer_alloc_read_page(iter
->trace_buffer
->buffer
,
4731 /* Do we have previous read data to read? */
4732 if (info
->read
< PAGE_SIZE
)
4736 trace_access_lock(iter
->cpu_file
);
4737 ret
= ring_buffer_read_page(iter
->trace_buffer
->buffer
,
4741 trace_access_unlock(iter
->cpu_file
);
4744 if (trace_empty(iter
)) {
4745 if ((filp
->f_flags
& O_NONBLOCK
)) {
4749 mutex_unlock(&trace_types_lock
);
4750 iter
->trace
->wait_pipe(iter
);
4751 mutex_lock(&trace_types_lock
);
4752 if (signal_pending(current
)) {
4764 size
= PAGE_SIZE
- info
->read
;
4768 ret
= copy_to_user(ubuf
, info
->spare
+ info
->read
, size
);
4779 mutex_unlock(&trace_types_lock
);
4784 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
)
4786 struct ftrace_buffer_info
*info
= file
->private_data
;
4787 struct trace_iterator
*iter
= &info
->iter
;
4789 mutex_lock(&trace_types_lock
);
4791 WARN_ON(!iter
->tr
->ref
);
4795 ring_buffer_free_read_page(iter
->trace_buffer
->buffer
, info
->spare
);
4798 mutex_unlock(&trace_types_lock
);
4804 struct ring_buffer
*buffer
;
4809 static void buffer_pipe_buf_release(struct pipe_inode_info
*pipe
,
4810 struct pipe_buffer
*buf
)
4812 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
4817 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
4822 static void buffer_pipe_buf_get(struct pipe_inode_info
*pipe
,
4823 struct pipe_buffer
*buf
)
4825 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
4830 /* Pipe buffer operations for a buffer. */
4831 static const struct pipe_buf_operations buffer_pipe_buf_ops
= {
4833 .map
= generic_pipe_buf_map
,
4834 .unmap
= generic_pipe_buf_unmap
,
4835 .confirm
= generic_pipe_buf_confirm
,
4836 .release
= buffer_pipe_buf_release
,
4837 .steal
= generic_pipe_buf_steal
,
4838 .get
= buffer_pipe_buf_get
,
4842 * Callback from splice_to_pipe(), if we need to release some pages
4843 * at the end of the spd in case we error'ed out in filling the pipe.
4845 static void buffer_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
4847 struct buffer_ref
*ref
=
4848 (struct buffer_ref
*)spd
->partial
[i
].private;
4853 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
4855 spd
->partial
[i
].private = 0;
4859 tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
4860 struct pipe_inode_info
*pipe
, size_t len
,
4863 struct ftrace_buffer_info
*info
= file
->private_data
;
4864 struct trace_iterator
*iter
= &info
->iter
;
4865 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
4866 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
4867 struct splice_pipe_desc spd
= {
4869 .partial
= partial_def
,
4870 .nr_pages_max
= PIPE_DEF_BUFFERS
,
4872 .ops
= &buffer_pipe_buf_ops
,
4873 .spd_release
= buffer_spd_release
,
4875 struct buffer_ref
*ref
;
4876 int entries
, size
, i
;
4879 mutex_lock(&trace_types_lock
);
4881 #ifdef CONFIG_TRACER_MAX_TRACE
4882 if (iter
->snapshot
&& iter
->tr
->current_trace
->use_max_tr
) {
4888 if (splice_grow_spd(pipe
, &spd
)) {
4893 if (*ppos
& (PAGE_SIZE
- 1)) {
4898 if (len
& (PAGE_SIZE
- 1)) {
4899 if (len
< PAGE_SIZE
) {
4907 trace_access_lock(iter
->cpu_file
);
4908 entries
= ring_buffer_entries_cpu(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
4910 for (i
= 0; i
< pipe
->buffers
&& len
&& entries
; i
++, len
-= PAGE_SIZE
) {
4914 ref
= kzalloc(sizeof(*ref
), GFP_KERNEL
);
4919 ref
->buffer
= iter
->trace_buffer
->buffer
;
4920 ref
->page
= ring_buffer_alloc_read_page(ref
->buffer
, iter
->cpu_file
);
4926 r
= ring_buffer_read_page(ref
->buffer
, &ref
->page
,
4927 len
, iter
->cpu_file
, 1);
4929 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
4935 * zero out any left over data, this is going to
4938 size
= ring_buffer_page_len(ref
->page
);
4939 if (size
< PAGE_SIZE
)
4940 memset(ref
->page
+ size
, 0, PAGE_SIZE
- size
);
4942 page
= virt_to_page(ref
->page
);
4944 spd
.pages
[i
] = page
;
4945 spd
.partial
[i
].len
= PAGE_SIZE
;
4946 spd
.partial
[i
].offset
= 0;
4947 spd
.partial
[i
].private = (unsigned long)ref
;
4951 entries
= ring_buffer_entries_cpu(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
4954 trace_access_unlock(iter
->cpu_file
);
4957 /* did we read anything? */
4958 if (!spd
.nr_pages
) {
4959 if ((file
->f_flags
& O_NONBLOCK
) || (flags
& SPLICE_F_NONBLOCK
)) {
4963 mutex_unlock(&trace_types_lock
);
4964 iter
->trace
->wait_pipe(iter
);
4965 mutex_lock(&trace_types_lock
);
4966 if (signal_pending(current
)) {
4973 ret
= splice_to_pipe(pipe
, &spd
);
4974 splice_shrink_spd(&spd
);
4976 mutex_unlock(&trace_types_lock
);
4981 static const struct file_operations tracing_buffers_fops
= {
4982 .open
= tracing_buffers_open
,
4983 .read
= tracing_buffers_read
,
4984 .poll
= tracing_buffers_poll
,
4985 .release
= tracing_buffers_release
,
4986 .splice_read
= tracing_buffers_splice_read
,
4987 .llseek
= no_llseek
,
4991 tracing_stats_read(struct file
*filp
, char __user
*ubuf
,
4992 size_t count
, loff_t
*ppos
)
4994 struct trace_cpu
*tc
= filp
->private_data
;
4995 struct trace_array
*tr
= tc
->tr
;
4996 struct trace_buffer
*trace_buf
= &tr
->trace_buffer
;
4997 struct trace_seq
*s
;
4999 unsigned long long t
;
5000 unsigned long usec_rem
;
5003 s
= kmalloc(sizeof(*s
), GFP_KERNEL
);
5009 cnt
= ring_buffer_entries_cpu(trace_buf
->buffer
, cpu
);
5010 trace_seq_printf(s
, "entries: %ld\n", cnt
);
5012 cnt
= ring_buffer_overrun_cpu(trace_buf
->buffer
, cpu
);
5013 trace_seq_printf(s
, "overrun: %ld\n", cnt
);
5015 cnt
= ring_buffer_commit_overrun_cpu(trace_buf
->buffer
, cpu
);
5016 trace_seq_printf(s
, "commit overrun: %ld\n", cnt
);
5018 cnt
= ring_buffer_bytes_cpu(trace_buf
->buffer
, cpu
);
5019 trace_seq_printf(s
, "bytes: %ld\n", cnt
);
5021 if (trace_clocks
[trace_clock_id
].in_ns
) {
5022 /* local or global for trace_clock */
5023 t
= ns2usecs(ring_buffer_oldest_event_ts(trace_buf
->buffer
, cpu
));
5024 usec_rem
= do_div(t
, USEC_PER_SEC
);
5025 trace_seq_printf(s
, "oldest event ts: %5llu.%06lu\n",
5028 t
= ns2usecs(ring_buffer_time_stamp(trace_buf
->buffer
, cpu
));
5029 usec_rem
= do_div(t
, USEC_PER_SEC
);
5030 trace_seq_printf(s
, "now ts: %5llu.%06lu\n", t
, usec_rem
);
5032 /* counter or tsc mode for trace_clock */
5033 trace_seq_printf(s
, "oldest event ts: %llu\n",
5034 ring_buffer_oldest_event_ts(trace_buf
->buffer
, cpu
));
5036 trace_seq_printf(s
, "now ts: %llu\n",
5037 ring_buffer_time_stamp(trace_buf
->buffer
, cpu
));
5040 cnt
= ring_buffer_dropped_events_cpu(trace_buf
->buffer
, cpu
);
5041 trace_seq_printf(s
, "dropped events: %ld\n", cnt
);
5043 cnt
= ring_buffer_read_events_cpu(trace_buf
->buffer
, cpu
);
5044 trace_seq_printf(s
, "read events: %ld\n", cnt
);
5046 count
= simple_read_from_buffer(ubuf
, count
, ppos
, s
->buffer
, s
->len
);
5053 static const struct file_operations tracing_stats_fops
= {
5054 .open
= tracing_open_generic
,
5055 .read
= tracing_stats_read
,
5056 .llseek
= generic_file_llseek
,
5059 #ifdef CONFIG_DYNAMIC_FTRACE
5061 int __weak
ftrace_arch_read_dyn_info(char *buf
, int size
)
5067 tracing_read_dyn_info(struct file
*filp
, char __user
*ubuf
,
5068 size_t cnt
, loff_t
*ppos
)
5070 static char ftrace_dyn_info_buffer
[1024];
5071 static DEFINE_MUTEX(dyn_info_mutex
);
5072 unsigned long *p
= filp
->private_data
;
5073 char *buf
= ftrace_dyn_info_buffer
;
5074 int size
= ARRAY_SIZE(ftrace_dyn_info_buffer
);
5077 mutex_lock(&dyn_info_mutex
);
5078 r
= sprintf(buf
, "%ld ", *p
);
5080 r
+= ftrace_arch_read_dyn_info(buf
+r
, (size
-1)-r
);
5083 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
5085 mutex_unlock(&dyn_info_mutex
);
5090 static const struct file_operations tracing_dyn_info_fops
= {
5091 .open
= tracing_open_generic
,
5092 .read
= tracing_read_dyn_info
,
5093 .llseek
= generic_file_llseek
,
5095 #endif /* CONFIG_DYNAMIC_FTRACE */
5097 #if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
5099 ftrace_snapshot(unsigned long ip
, unsigned long parent_ip
, void **data
)
5105 ftrace_count_snapshot(unsigned long ip
, unsigned long parent_ip
, void **data
)
5107 unsigned long *count
= (long *)data
;
5119 ftrace_snapshot_print(struct seq_file
*m
, unsigned long ip
,
5120 struct ftrace_probe_ops
*ops
, void *data
)
5122 long count
= (long)data
;
5124 seq_printf(m
, "%ps:", (void *)ip
);
5126 seq_printf(m
, "snapshot");
5129 seq_printf(m
, ":unlimited\n");
5131 seq_printf(m
, ":count=%ld\n", count
);
5136 static struct ftrace_probe_ops snapshot_probe_ops
= {
5137 .func
= ftrace_snapshot
,
5138 .print
= ftrace_snapshot_print
,
5141 static struct ftrace_probe_ops snapshot_count_probe_ops
= {
5142 .func
= ftrace_count_snapshot
,
5143 .print
= ftrace_snapshot_print
,
5147 ftrace_trace_snapshot_callback(struct ftrace_hash
*hash
,
5148 char *glob
, char *cmd
, char *param
, int enable
)
5150 struct ftrace_probe_ops
*ops
;
5151 void *count
= (void *)-1;
5155 /* hash funcs only work with set_ftrace_filter */
5159 ops
= param
? &snapshot_count_probe_ops
: &snapshot_probe_ops
;
5161 if (glob
[0] == '!') {
5162 unregister_ftrace_function_probe_func(glob
+1, ops
);
5169 number
= strsep(¶m
, ":");
5171 if (!strlen(number
))
5175 * We use the callback data field (which is a pointer)
5178 ret
= kstrtoul(number
, 0, (unsigned long *)&count
);
5183 ret
= register_ftrace_function_probe(glob
, ops
, count
);
5186 alloc_snapshot(&global_trace
);
5188 return ret
< 0 ? ret
: 0;
5191 static struct ftrace_func_command ftrace_snapshot_cmd
= {
5193 .func
= ftrace_trace_snapshot_callback
,
5196 static int register_snapshot_cmd(void)
5198 return register_ftrace_command(&ftrace_snapshot_cmd
);
5201 static inline int register_snapshot_cmd(void) { return 0; }
5202 #endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
5204 struct dentry
*tracing_init_dentry_tr(struct trace_array
*tr
)
5211 if (!debugfs_initialized())
5214 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
5215 tr
->dir
= debugfs_create_dir("tracing", NULL
);
5217 if (!tr
->dir
&& !once
) {
5219 pr_warning("Could not create debugfs directory 'tracing'\n");
5226 struct dentry
*tracing_init_dentry(void)
5228 return tracing_init_dentry_tr(&global_trace
);
5231 static struct dentry
*tracing_dentry_percpu(struct trace_array
*tr
, int cpu
)
5233 struct dentry
*d_tracer
;
5236 return tr
->percpu_dir
;
5238 d_tracer
= tracing_init_dentry_tr(tr
);
5242 tr
->percpu_dir
= debugfs_create_dir("per_cpu", d_tracer
);
5244 WARN_ONCE(!tr
->percpu_dir
,
5245 "Could not create debugfs directory 'per_cpu/%d'\n", cpu
);
5247 return tr
->percpu_dir
;
5251 tracing_init_debugfs_percpu(struct trace_array
*tr
, long cpu
)
5253 struct trace_array_cpu
*data
= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
);
5254 struct dentry
*d_percpu
= tracing_dentry_percpu(tr
, cpu
);
5255 struct dentry
*d_cpu
;
5256 char cpu_dir
[30]; /* 30 characters should be more than enough */
5261 snprintf(cpu_dir
, 30, "cpu%ld", cpu
);
5262 d_cpu
= debugfs_create_dir(cpu_dir
, d_percpu
);
5264 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir
);
5268 /* per cpu trace_pipe */
5269 trace_create_file("trace_pipe", 0444, d_cpu
,
5270 (void *)&data
->trace_cpu
, &tracing_pipe_fops
);
5273 trace_create_file("trace", 0644, d_cpu
,
5274 (void *)&data
->trace_cpu
, &tracing_fops
);
5276 trace_create_file("trace_pipe_raw", 0444, d_cpu
,
5277 (void *)&data
->trace_cpu
, &tracing_buffers_fops
);
5279 trace_create_file("stats", 0444, d_cpu
,
5280 (void *)&data
->trace_cpu
, &tracing_stats_fops
);
5282 trace_create_file("buffer_size_kb", 0444, d_cpu
,
5283 (void *)&data
->trace_cpu
, &tracing_entries_fops
);
5285 #ifdef CONFIG_TRACER_SNAPSHOT
5286 trace_create_file("snapshot", 0644, d_cpu
,
5287 (void *)&data
->trace_cpu
, &snapshot_fops
);
5289 trace_create_file("snapshot_raw", 0444, d_cpu
,
5290 (void *)&data
->trace_cpu
, &snapshot_raw_fops
);
5294 #ifdef CONFIG_FTRACE_SELFTEST
5295 /* Let selftest have access to static functions in this file */
5296 #include "trace_selftest.c"
5299 struct trace_option_dentry
{
5300 struct tracer_opt
*opt
;
5301 struct tracer_flags
*flags
;
5302 struct trace_array
*tr
;
5303 struct dentry
*entry
;
5307 trace_options_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
5310 struct trace_option_dentry
*topt
= filp
->private_data
;
5313 if (topt
->flags
->val
& topt
->opt
->bit
)
5318 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
5322 trace_options_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
5325 struct trace_option_dentry
*topt
= filp
->private_data
;
5329 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5333 if (val
!= 0 && val
!= 1)
5336 if (!!(topt
->flags
->val
& topt
->opt
->bit
) != val
) {
5337 mutex_lock(&trace_types_lock
);
5338 ret
= __set_tracer_option(topt
->tr
->current_trace
, topt
->flags
,
5340 mutex_unlock(&trace_types_lock
);
5351 static const struct file_operations trace_options_fops
= {
5352 .open
= tracing_open_generic
,
5353 .read
= trace_options_read
,
5354 .write
= trace_options_write
,
5355 .llseek
= generic_file_llseek
,
5359 trace_options_core_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
5362 long index
= (long)filp
->private_data
;
5365 if (trace_flags
& (1 << index
))
5370 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
5374 trace_options_core_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
5377 struct trace_array
*tr
= &global_trace
;
5378 long index
= (long)filp
->private_data
;
5382 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5386 if (val
!= 0 && val
!= 1)
5389 mutex_lock(&trace_types_lock
);
5390 ret
= set_tracer_flag(tr
, 1 << index
, val
);
5391 mutex_unlock(&trace_types_lock
);
5401 static const struct file_operations trace_options_core_fops
= {
5402 .open
= tracing_open_generic
,
5403 .read
= trace_options_core_read
,
5404 .write
= trace_options_core_write
,
5405 .llseek
= generic_file_llseek
,
5408 struct dentry
*trace_create_file(const char *name
,
5410 struct dentry
*parent
,
5412 const struct file_operations
*fops
)
5416 ret
= debugfs_create_file(name
, mode
, parent
, data
, fops
);
5418 pr_warning("Could not create debugfs '%s' entry\n", name
);
5424 static struct dentry
*trace_options_init_dentry(struct trace_array
*tr
)
5426 struct dentry
*d_tracer
;
5431 d_tracer
= tracing_init_dentry_tr(tr
);
5435 tr
->options
= debugfs_create_dir("options", d_tracer
);
5437 pr_warning("Could not create debugfs directory 'options'\n");
5445 create_trace_option_file(struct trace_array
*tr
,
5446 struct trace_option_dentry
*topt
,
5447 struct tracer_flags
*flags
,
5448 struct tracer_opt
*opt
)
5450 struct dentry
*t_options
;
5452 t_options
= trace_options_init_dentry(tr
);
5456 topt
->flags
= flags
;
5460 topt
->entry
= trace_create_file(opt
->name
, 0644, t_options
, topt
,
5461 &trace_options_fops
);
5465 static struct trace_option_dentry
*
5466 create_trace_option_files(struct trace_array
*tr
, struct tracer
*tracer
)
5468 struct trace_option_dentry
*topts
;
5469 struct tracer_flags
*flags
;
5470 struct tracer_opt
*opts
;
5476 flags
= tracer
->flags
;
5478 if (!flags
|| !flags
->opts
)
5483 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
5486 topts
= kcalloc(cnt
+ 1, sizeof(*topts
), GFP_KERNEL
);
5490 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
5491 create_trace_option_file(tr
, &topts
[cnt
], flags
,
5498 destroy_trace_option_files(struct trace_option_dentry
*topts
)
5505 for (cnt
= 0; topts
[cnt
].opt
; cnt
++) {
5506 if (topts
[cnt
].entry
)
5507 debugfs_remove(topts
[cnt
].entry
);
5513 static struct dentry
*
5514 create_trace_option_core_file(struct trace_array
*tr
,
5515 const char *option
, long index
)
5517 struct dentry
*t_options
;
5519 t_options
= trace_options_init_dentry(tr
);
5523 return trace_create_file(option
, 0644, t_options
, (void *)index
,
5524 &trace_options_core_fops
);
5527 static __init
void create_trace_options_dir(struct trace_array
*tr
)
5529 struct dentry
*t_options
;
5532 t_options
= trace_options_init_dentry(tr
);
5536 for (i
= 0; trace_options
[i
]; i
++)
5537 create_trace_option_core_file(tr
, trace_options
[i
], i
);
5541 rb_simple_read(struct file
*filp
, char __user
*ubuf
,
5542 size_t cnt
, loff_t
*ppos
)
5544 struct trace_array
*tr
= filp
->private_data
;
5545 struct ring_buffer
*buffer
= tr
->trace_buffer
.buffer
;
5550 r
= ring_buffer_record_is_on(buffer
);
5554 r
= sprintf(buf
, "%d\n", r
);
5556 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
5560 rb_simple_write(struct file
*filp
, const char __user
*ubuf
,
5561 size_t cnt
, loff_t
*ppos
)
5563 struct trace_array
*tr
= filp
->private_data
;
5564 struct ring_buffer
*buffer
= tr
->trace_buffer
.buffer
;
5568 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5573 mutex_lock(&trace_types_lock
);
5575 ring_buffer_record_on(buffer
);
5576 if (tr
->current_trace
->start
)
5577 tr
->current_trace
->start(tr
);
5579 ring_buffer_record_off(buffer
);
5580 if (tr
->current_trace
->stop
)
5581 tr
->current_trace
->stop(tr
);
5583 mutex_unlock(&trace_types_lock
);
5591 static const struct file_operations rb_simple_fops
= {
5592 .open
= tracing_open_generic
,
5593 .read
= rb_simple_read
,
5594 .write
= rb_simple_write
,
5595 .llseek
= default_llseek
,
5598 struct dentry
*trace_instance_dir
;
5601 init_tracer_debugfs(struct trace_array
*tr
, struct dentry
*d_tracer
);
5603 static void init_trace_buffers(struct trace_array
*tr
, struct trace_buffer
*buf
)
5607 for_each_tracing_cpu(cpu
) {
5608 memset(per_cpu_ptr(buf
->data
, cpu
), 0, sizeof(struct trace_array_cpu
));
5609 per_cpu_ptr(buf
->data
, cpu
)->trace_cpu
.cpu
= cpu
;
5610 per_cpu_ptr(buf
->data
, cpu
)->trace_cpu
.tr
= tr
;
5615 allocate_trace_buffer(struct trace_array
*tr
, struct trace_buffer
*buf
, int size
)
5617 enum ring_buffer_flags rb_flags
;
5619 rb_flags
= trace_flags
& TRACE_ITER_OVERWRITE
? RB_FL_OVERWRITE
: 0;
5621 buf
->buffer
= ring_buffer_alloc(size
, rb_flags
);
5625 buf
->data
= alloc_percpu(struct trace_array_cpu
);
5627 ring_buffer_free(buf
->buffer
);
5631 init_trace_buffers(tr
, buf
);
5633 /* Allocate the first page for all buffers */
5634 set_buffer_entries(&tr
->trace_buffer
,
5635 ring_buffer_size(tr
->trace_buffer
.buffer
, 0));
5640 static int allocate_trace_buffers(struct trace_array
*tr
, int size
)
5644 ret
= allocate_trace_buffer(tr
, &tr
->trace_buffer
, size
);
5648 #ifdef CONFIG_TRACER_MAX_TRACE
5649 ret
= allocate_trace_buffer(tr
, &tr
->max_buffer
,
5650 allocate_snapshot
? size
: 1);
5652 ring_buffer_free(tr
->trace_buffer
.buffer
);
5653 free_percpu(tr
->trace_buffer
.data
);
5656 tr
->allocated_snapshot
= allocate_snapshot
;
5659 * Only the top level trace array gets its snapshot allocated
5660 * from the kernel command line.
5662 allocate_snapshot
= false;
5667 static int new_instance_create(const char *name
)
5669 struct trace_array
*tr
;
5672 mutex_lock(&trace_types_lock
);
5675 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
5676 if (tr
->name
&& strcmp(tr
->name
, name
) == 0)
5681 tr
= kzalloc(sizeof(*tr
), GFP_KERNEL
);
5685 tr
->name
= kstrdup(name
, GFP_KERNEL
);
5689 raw_spin_lock_init(&tr
->start_lock
);
5691 tr
->current_trace
= &nop_trace
;
5693 INIT_LIST_HEAD(&tr
->systems
);
5694 INIT_LIST_HEAD(&tr
->events
);
5696 if (allocate_trace_buffers(tr
, trace_buf_size
) < 0)
5699 /* Holder for file callbacks */
5700 tr
->trace_cpu
.cpu
= RING_BUFFER_ALL_CPUS
;
5701 tr
->trace_cpu
.tr
= tr
;
5703 tr
->dir
= debugfs_create_dir(name
, trace_instance_dir
);
5707 ret
= event_trace_add_tracer(tr
->dir
, tr
);
5711 init_tracer_debugfs(tr
, tr
->dir
);
5713 list_add(&tr
->list
, &ftrace_trace_arrays
);
5715 mutex_unlock(&trace_types_lock
);
5720 if (tr
->trace_buffer
.buffer
)
5721 ring_buffer_free(tr
->trace_buffer
.buffer
);
5726 mutex_unlock(&trace_types_lock
);
5732 static int instance_delete(const char *name
)
5734 struct trace_array
*tr
;
5738 mutex_lock(&trace_types_lock
);
5741 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
5742 if (tr
->name
&& strcmp(tr
->name
, name
) == 0) {
5754 list_del(&tr
->list
);
5756 event_trace_del_tracer(tr
);
5757 debugfs_remove_recursive(tr
->dir
);
5758 free_percpu(tr
->trace_buffer
.data
);
5759 ring_buffer_free(tr
->trace_buffer
.buffer
);
5767 mutex_unlock(&trace_types_lock
);
5772 static int instance_mkdir (struct inode
*inode
, struct dentry
*dentry
, umode_t mode
)
5774 struct dentry
*parent
;
5777 /* Paranoid: Make sure the parent is the "instances" directory */
5778 parent
= hlist_entry(inode
->i_dentry
.first
, struct dentry
, d_alias
);
5779 if (WARN_ON_ONCE(parent
!= trace_instance_dir
))
5783 * The inode mutex is locked, but debugfs_create_dir() will also
5784 * take the mutex. As the instances directory can not be destroyed
5785 * or changed in any other way, it is safe to unlock it, and
5786 * let the dentry try. If two users try to make the same dir at
5787 * the same time, then the new_instance_create() will determine the
5790 mutex_unlock(&inode
->i_mutex
);
5792 ret
= new_instance_create(dentry
->d_iname
);
5794 mutex_lock(&inode
->i_mutex
);
5799 static int instance_rmdir(struct inode
*inode
, struct dentry
*dentry
)
5801 struct dentry
*parent
;
5804 /* Paranoid: Make sure the parent is the "instances" directory */
5805 parent
= hlist_entry(inode
->i_dentry
.first
, struct dentry
, d_alias
);
5806 if (WARN_ON_ONCE(parent
!= trace_instance_dir
))
5809 /* The caller did a dget() on dentry */
5810 mutex_unlock(&dentry
->d_inode
->i_mutex
);
5813 * The inode mutex is locked, but debugfs_create_dir() will also
5814 * take the mutex. As the instances directory can not be destroyed
5815 * or changed in any other way, it is safe to unlock it, and
5816 * let the dentry try. If two users try to make the same dir at
5817 * the same time, then the instance_delete() will determine the
5820 mutex_unlock(&inode
->i_mutex
);
5822 ret
= instance_delete(dentry
->d_iname
);
5824 mutex_lock_nested(&inode
->i_mutex
, I_MUTEX_PARENT
);
5825 mutex_lock(&dentry
->d_inode
->i_mutex
);
5830 static const struct inode_operations instance_dir_inode_operations
= {
5831 .lookup
= simple_lookup
,
5832 .mkdir
= instance_mkdir
,
5833 .rmdir
= instance_rmdir
,
5836 static __init
void create_trace_instances(struct dentry
*d_tracer
)
5838 trace_instance_dir
= debugfs_create_dir("instances", d_tracer
);
5839 if (WARN_ON(!trace_instance_dir
))
5842 /* Hijack the dir inode operations, to allow mkdir */
5843 trace_instance_dir
->d_inode
->i_op
= &instance_dir_inode_operations
;
5847 init_tracer_debugfs(struct trace_array
*tr
, struct dentry
*d_tracer
)
5851 trace_create_file("trace_options", 0644, d_tracer
,
5852 tr
, &tracing_iter_fops
);
5854 trace_create_file("trace", 0644, d_tracer
,
5855 (void *)&tr
->trace_cpu
, &tracing_fops
);
5857 trace_create_file("trace_pipe", 0444, d_tracer
,
5858 (void *)&tr
->trace_cpu
, &tracing_pipe_fops
);
5860 trace_create_file("buffer_size_kb", 0644, d_tracer
,
5861 (void *)&tr
->trace_cpu
, &tracing_entries_fops
);
5863 trace_create_file("buffer_total_size_kb", 0444, d_tracer
,
5864 tr
, &tracing_total_entries_fops
);
5866 trace_create_file("free_buffer", 0644, d_tracer
,
5867 tr
, &tracing_free_buffer_fops
);
5869 trace_create_file("trace_marker", 0220, d_tracer
,
5870 tr
, &tracing_mark_fops
);
5872 trace_create_file("trace_clock", 0644, d_tracer
, tr
,
5875 trace_create_file("tracing_on", 0644, d_tracer
,
5876 tr
, &rb_simple_fops
);
5878 #ifdef CONFIG_TRACER_SNAPSHOT
5879 trace_create_file("snapshot", 0644, d_tracer
,
5880 (void *)&tr
->trace_cpu
, &snapshot_fops
);
5883 for_each_tracing_cpu(cpu
)
5884 tracing_init_debugfs_percpu(tr
, cpu
);
5888 static __init
int tracer_init_debugfs(void)
5890 struct dentry
*d_tracer
;
5892 trace_access_lock_init();
5894 d_tracer
= tracing_init_dentry();
5896 init_tracer_debugfs(&global_trace
, d_tracer
);
5898 trace_create_file("tracing_cpumask", 0644, d_tracer
,
5899 &global_trace
, &tracing_cpumask_fops
);
5901 trace_create_file("available_tracers", 0444, d_tracer
,
5902 &global_trace
, &show_traces_fops
);
5904 trace_create_file("current_tracer", 0644, d_tracer
,
5905 &global_trace
, &set_tracer_fops
);
5907 #ifdef CONFIG_TRACER_MAX_TRACE
5908 trace_create_file("tracing_max_latency", 0644, d_tracer
,
5909 &tracing_max_latency
, &tracing_max_lat_fops
);
5912 trace_create_file("tracing_thresh", 0644, d_tracer
,
5913 &tracing_thresh
, &tracing_max_lat_fops
);
5915 trace_create_file("README", 0444, d_tracer
,
5916 NULL
, &tracing_readme_fops
);
5918 trace_create_file("saved_cmdlines", 0444, d_tracer
,
5919 NULL
, &tracing_saved_cmdlines_fops
);
5921 #ifdef CONFIG_DYNAMIC_FTRACE
5922 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
5923 &ftrace_update_tot_cnt
, &tracing_dyn_info_fops
);
5926 create_trace_instances(d_tracer
);
5928 create_trace_options_dir(&global_trace
);
5933 static int trace_panic_handler(struct notifier_block
*this,
5934 unsigned long event
, void *unused
)
5936 if (ftrace_dump_on_oops
)
5937 ftrace_dump(ftrace_dump_on_oops
);
5941 static struct notifier_block trace_panic_notifier
= {
5942 .notifier_call
= trace_panic_handler
,
5944 .priority
= 150 /* priority: INT_MAX >= x >= 0 */
5947 static int trace_die_handler(struct notifier_block
*self
,
5953 if (ftrace_dump_on_oops
)
5954 ftrace_dump(ftrace_dump_on_oops
);
5962 static struct notifier_block trace_die_notifier
= {
5963 .notifier_call
= trace_die_handler
,
5968 * printk is set to max of 1024, we really don't need it that big.
5969 * Nothing should be printing 1000 characters anyway.
5971 #define TRACE_MAX_PRINT 1000
5974 * Define here KERN_TRACE so that we have one place to modify
5975 * it if we decide to change what log level the ftrace dump
5978 #define KERN_TRACE KERN_EMERG
5981 trace_printk_seq(struct trace_seq
*s
)
5983 /* Probably should print a warning here. */
5987 /* should be zero ended, but we are paranoid. */
5988 s
->buffer
[s
->len
] = 0;
5990 printk(KERN_TRACE
"%s", s
->buffer
);
5995 void trace_init_global_iter(struct trace_iterator
*iter
)
5997 iter
->tr
= &global_trace
;
5998 iter
->trace
= iter
->tr
->current_trace
;
5999 iter
->cpu_file
= RING_BUFFER_ALL_CPUS
;
6000 iter
->trace_buffer
= &global_trace
.trace_buffer
;
6004 __ftrace_dump(bool disable_tracing
, enum ftrace_dump_mode oops_dump_mode
)
6006 static arch_spinlock_t ftrace_dump_lock
=
6007 (arch_spinlock_t
)__ARCH_SPIN_LOCK_UNLOCKED
;
6008 /* use static because iter can be a bit big for the stack */
6009 static struct trace_iterator iter
;
6010 unsigned int old_userobj
;
6011 static int dump_ran
;
6012 unsigned long flags
;
6016 local_irq_save(flags
);
6017 arch_spin_lock(&ftrace_dump_lock
);
6025 /* Did function tracer already get disabled? */
6026 if (ftrace_is_dead()) {
6027 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
6028 printk("# MAY BE MISSING FUNCTION EVENTS\n");
6031 if (disable_tracing
)
6034 /* Simulate the iterator */
6035 trace_init_global_iter(&iter
);
6037 for_each_tracing_cpu(cpu
) {
6038 atomic_inc(&per_cpu_ptr(iter
.tr
->trace_buffer
.data
, cpu
)->disabled
);
6041 old_userobj
= trace_flags
& TRACE_ITER_SYM_USEROBJ
;
6043 /* don't look at user memory in panic mode */
6044 trace_flags
&= ~TRACE_ITER_SYM_USEROBJ
;
6046 switch (oops_dump_mode
) {
6048 iter
.cpu_file
= RING_BUFFER_ALL_CPUS
;
6051 iter
.cpu_file
= raw_smp_processor_id();
6056 printk(KERN_TRACE
"Bad dumping mode, switching to all CPUs dump\n");
6057 iter
.cpu_file
= RING_BUFFER_ALL_CPUS
;
6060 printk(KERN_TRACE
"Dumping ftrace buffer:\n");
6063 * We need to stop all tracing on all CPUS to read the
6064 * the next buffer. This is a bit expensive, but is
6065 * not done often. We fill all what we can read,
6066 * and then release the locks again.
6069 while (!trace_empty(&iter
)) {
6072 printk(KERN_TRACE
"---------------------------------\n");
6076 /* reset all but tr, trace, and overruns */
6077 memset(&iter
.seq
, 0,
6078 sizeof(struct trace_iterator
) -
6079 offsetof(struct trace_iterator
, seq
));
6080 iter
.iter_flags
|= TRACE_FILE_LAT_FMT
;
6083 if (trace_find_next_entry_inc(&iter
) != NULL
) {
6086 ret
= print_trace_line(&iter
);
6087 if (ret
!= TRACE_TYPE_NO_CONSUME
)
6088 trace_consume(&iter
);
6090 touch_nmi_watchdog();
6092 trace_printk_seq(&iter
.seq
);
6096 printk(KERN_TRACE
" (ftrace buffer empty)\n");
6098 printk(KERN_TRACE
"---------------------------------\n");
6101 /* Re-enable tracing if requested */
6102 if (!disable_tracing
) {
6103 trace_flags
|= old_userobj
;
6105 for_each_tracing_cpu(cpu
) {
6106 atomic_dec(&per_cpu_ptr(iter
.trace_buffer
->data
, cpu
)->disabled
);
6112 arch_spin_unlock(&ftrace_dump_lock
);
6113 local_irq_restore(flags
);
6116 /* By default: disable tracing after the dump */
6117 void ftrace_dump(enum ftrace_dump_mode oops_dump_mode
)
6119 __ftrace_dump(true, oops_dump_mode
);
6121 EXPORT_SYMBOL_GPL(ftrace_dump
);
6123 __init
static int tracer_alloc_buffers(void)
6129 if (!alloc_cpumask_var(&tracing_buffer_mask
, GFP_KERNEL
))
6132 if (!alloc_cpumask_var(&tracing_cpumask
, GFP_KERNEL
))
6133 goto out_free_buffer_mask
;
6135 /* Only allocate trace_printk buffers if a trace_printk exists */
6136 if (__stop___trace_bprintk_fmt
!= __start___trace_bprintk_fmt
)
6137 /* Must be called before global_trace.buffer is allocated */
6138 trace_printk_init_buffers();
6140 /* To save memory, keep the ring buffer size to its minimum */
6141 if (ring_buffer_expanded
)
6142 ring_buf_size
= trace_buf_size
;
6146 cpumask_copy(tracing_buffer_mask
, cpu_possible_mask
);
6147 cpumask_copy(tracing_cpumask
, cpu_all_mask
);
6149 raw_spin_lock_init(&global_trace
.start_lock
);
6151 /* TODO: make the number of buffers hot pluggable with CPUS */
6152 if (allocate_trace_buffers(&global_trace
, ring_buf_size
) < 0) {
6153 printk(KERN_ERR
"tracer: failed to allocate ring buffer!\n");
6155 goto out_free_cpumask
;
6158 if (global_trace
.buffer_disabled
)
6161 trace_init_cmdlines();
6163 register_tracer(&nop_trace
);
6165 global_trace
.current_trace
= &nop_trace
;
6167 /* All seems OK, enable tracing */
6168 tracing_disabled
= 0;
6170 atomic_notifier_chain_register(&panic_notifier_list
,
6171 &trace_panic_notifier
);
6173 register_die_notifier(&trace_die_notifier
);
6175 global_trace
.flags
= TRACE_ARRAY_FL_GLOBAL
;
6177 /* Holder for file callbacks */
6178 global_trace
.trace_cpu
.cpu
= RING_BUFFER_ALL_CPUS
;
6179 global_trace
.trace_cpu
.tr
= &global_trace
;
6181 INIT_LIST_HEAD(&global_trace
.systems
);
6182 INIT_LIST_HEAD(&global_trace
.events
);
6183 list_add(&global_trace
.list
, &ftrace_trace_arrays
);
6185 while (trace_boot_options
) {
6188 option
= strsep(&trace_boot_options
, ",");
6189 trace_set_options(&global_trace
, option
);
6192 register_snapshot_cmd();
6197 free_percpu(global_trace
.trace_buffer
.data
);
6198 #ifdef CONFIG_TRACER_MAX_TRACE
6199 free_percpu(global_trace
.max_buffer
.data
);
6201 free_cpumask_var(tracing_cpumask
);
6202 out_free_buffer_mask
:
6203 free_cpumask_var(tracing_buffer_mask
);
6208 __init
static int clear_boot_tracer(void)
6211 * The default tracer at boot buffer is an init section.
6212 * This function is called in lateinit. If we did not
6213 * find the boot tracer, then clear it out, to prevent
6214 * later registration from accessing the buffer that is
6215 * about to be freed.
6217 if (!default_bootup_tracer
)
6220 printk(KERN_INFO
"ftrace bootup tracer '%s' not registered.\n",
6221 default_bootup_tracer
);
6222 default_bootup_tracer
= NULL
;
6227 early_initcall(tracer_alloc_buffers
);
6228 fs_initcall(tracer_init_debugfs
);
6229 late_initcall(clear_boot_tracer
);