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 strlcpy(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 strlcpy(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 },
650 { trace_clock_jiffies
, "uptime", 1 },
651 { trace_clock
, "perf", 1 },
658 * trace_parser_get_init - gets the buffer for trace parser
660 int trace_parser_get_init(struct trace_parser
*parser
, int size
)
662 memset(parser
, 0, sizeof(*parser
));
664 parser
->buffer
= kmalloc(size
, GFP_KERNEL
);
673 * trace_parser_put - frees the buffer for trace parser
675 void trace_parser_put(struct trace_parser
*parser
)
677 kfree(parser
->buffer
);
681 * trace_get_user - reads the user input string separated by space
682 * (matched by isspace(ch))
684 * For each string found the 'struct trace_parser' is updated,
685 * and the function returns.
687 * Returns number of bytes read.
689 * See kernel/trace/trace.h for 'struct trace_parser' details.
691 int trace_get_user(struct trace_parser
*parser
, const char __user
*ubuf
,
692 size_t cnt
, loff_t
*ppos
)
699 trace_parser_clear(parser
);
701 ret
= get_user(ch
, ubuf
++);
709 * The parser is not finished with the last write,
710 * continue reading the user input without skipping spaces.
713 /* skip white space */
714 while (cnt
&& isspace(ch
)) {
715 ret
= get_user(ch
, ubuf
++);
722 /* only spaces were written */
732 /* read the non-space input */
733 while (cnt
&& !isspace(ch
)) {
734 if (parser
->idx
< parser
->size
- 1)
735 parser
->buffer
[parser
->idx
++] = ch
;
740 ret
= get_user(ch
, ubuf
++);
747 /* We either got finished input or we have to wait for another call. */
749 parser
->buffer
[parser
->idx
] = 0;
750 parser
->cont
= false;
753 parser
->buffer
[parser
->idx
++] = ch
;
763 ssize_t
trace_seq_to_user(struct trace_seq
*s
, char __user
*ubuf
, size_t cnt
)
771 if (s
->len
<= s
->readpos
)
774 len
= s
->len
- s
->readpos
;
777 ret
= copy_to_user(ubuf
, s
->buffer
+ s
->readpos
, cnt
);
787 static ssize_t
trace_seq_to_buffer(struct trace_seq
*s
, void *buf
, size_t cnt
)
791 if (s
->len
<= s
->readpos
)
794 len
= s
->len
- s
->readpos
;
797 memcpy(buf
, s
->buffer
+ s
->readpos
, cnt
);
804 * ftrace_max_lock is used to protect the swapping of buffers
805 * when taking a max snapshot. The buffers themselves are
806 * protected by per_cpu spinlocks. But the action of the swap
807 * needs its own lock.
809 * This is defined as a arch_spinlock_t in order to help
810 * with performance when lockdep debugging is enabled.
812 * It is also used in other places outside the update_max_tr
813 * so it needs to be defined outside of the
814 * CONFIG_TRACER_MAX_TRACE.
816 static arch_spinlock_t ftrace_max_lock
=
817 (arch_spinlock_t
)__ARCH_SPIN_LOCK_UNLOCKED
;
819 unsigned long __read_mostly tracing_thresh
;
821 #ifdef CONFIG_TRACER_MAX_TRACE
822 unsigned long __read_mostly tracing_max_latency
;
825 * Copy the new maximum trace into the separate maximum-trace
826 * structure. (this way the maximum trace is permanently saved,
827 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
830 __update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
832 struct trace_buffer
*trace_buf
= &tr
->trace_buffer
;
833 struct trace_buffer
*max_buf
= &tr
->max_buffer
;
834 struct trace_array_cpu
*data
= per_cpu_ptr(trace_buf
->data
, cpu
);
835 struct trace_array_cpu
*max_data
= per_cpu_ptr(max_buf
->data
, cpu
);
838 max_buf
->time_start
= data
->preempt_timestamp
;
840 max_data
->saved_latency
= tracing_max_latency
;
841 max_data
->critical_start
= data
->critical_start
;
842 max_data
->critical_end
= data
->critical_end
;
844 memcpy(max_data
->comm
, tsk
->comm
, TASK_COMM_LEN
);
845 max_data
->pid
= tsk
->pid
;
847 * If tsk == current, then use current_uid(), as that does not use
848 * RCU. The irq tracer can be called out of RCU scope.
851 max_data
->uid
= current_uid();
853 max_data
->uid
= task_uid(tsk
);
855 max_data
->nice
= tsk
->static_prio
- 20 - MAX_RT_PRIO
;
856 max_data
->policy
= tsk
->policy
;
857 max_data
->rt_priority
= tsk
->rt_priority
;
859 /* record this tasks comm */
860 tracing_record_cmdline(tsk
);
864 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
866 * @tsk: the task with the latency
867 * @cpu: The cpu that initiated the trace.
869 * Flip the buffers between the @tr and the max_tr and record information
870 * about which task was the cause of this latency.
873 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
875 struct ring_buffer
*buf
;
880 WARN_ON_ONCE(!irqs_disabled());
882 if (!tr
->allocated_snapshot
) {
883 /* Only the nop tracer should hit this when disabling */
884 WARN_ON_ONCE(tr
->current_trace
!= &nop_trace
);
888 arch_spin_lock(&ftrace_max_lock
);
890 buf
= tr
->trace_buffer
.buffer
;
891 tr
->trace_buffer
.buffer
= tr
->max_buffer
.buffer
;
892 tr
->max_buffer
.buffer
= buf
;
894 __update_max_tr(tr
, tsk
, cpu
);
895 arch_spin_unlock(&ftrace_max_lock
);
899 * update_max_tr_single - only copy one trace over, and reset the rest
901 * @tsk - task with the latency
902 * @cpu - the cpu of the buffer to copy.
904 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
907 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
914 WARN_ON_ONCE(!irqs_disabled());
915 if (!tr
->allocated_snapshot
) {
916 /* Only the nop tracer should hit this when disabling */
917 WARN_ON_ONCE(tr
->current_trace
!= &nop_trace
);
921 arch_spin_lock(&ftrace_max_lock
);
923 ret
= ring_buffer_swap_cpu(tr
->max_buffer
.buffer
, tr
->trace_buffer
.buffer
, cpu
);
927 * We failed to swap the buffer due to a commit taking
928 * place on this CPU. We fail to record, but we reset
929 * the max trace buffer (no one writes directly to it)
930 * and flag that it failed.
932 trace_array_printk_buf(tr
->max_buffer
.buffer
, _THIS_IP_
,
933 "Failed to swap buffers due to commit in progress\n");
936 WARN_ON_ONCE(ret
&& ret
!= -EAGAIN
&& ret
!= -EBUSY
);
938 __update_max_tr(tr
, tsk
, cpu
);
939 arch_spin_unlock(&ftrace_max_lock
);
941 #endif /* CONFIG_TRACER_MAX_TRACE */
943 static void default_wait_pipe(struct trace_iterator
*iter
)
945 /* Iterators are static, they should be filled or empty */
946 if (trace_buffer_iter(iter
, iter
->cpu_file
))
949 ring_buffer_wait(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
952 #ifdef CONFIG_FTRACE_STARTUP_TEST
953 static int run_tracer_selftest(struct tracer
*type
)
955 struct trace_array
*tr
= &global_trace
;
956 struct tracer
*saved_tracer
= tr
->current_trace
;
959 if (!type
->selftest
|| tracing_selftest_disabled
)
963 * Run a selftest on this tracer.
964 * Here we reset the trace buffer, and set the current
965 * tracer to be this tracer. The tracer can then run some
966 * internal tracing to verify that everything is in order.
967 * If we fail, we do not register this tracer.
969 tracing_reset_online_cpus(&tr
->trace_buffer
);
971 tr
->current_trace
= type
;
973 #ifdef CONFIG_TRACER_MAX_TRACE
974 if (type
->use_max_tr
) {
975 /* If we expanded the buffers, make sure the max is expanded too */
976 if (ring_buffer_expanded
)
977 ring_buffer_resize(tr
->max_buffer
.buffer
, trace_buf_size
,
978 RING_BUFFER_ALL_CPUS
);
979 tr
->allocated_snapshot
= true;
983 /* the test is responsible for initializing and enabling */
984 pr_info("Testing tracer %s: ", type
->name
);
985 ret
= type
->selftest(type
, tr
);
986 /* the test is responsible for resetting too */
987 tr
->current_trace
= saved_tracer
;
989 printk(KERN_CONT
"FAILED!\n");
990 /* Add the warning after printing 'FAILED' */
994 /* Only reset on passing, to avoid touching corrupted buffers */
995 tracing_reset_online_cpus(&tr
->trace_buffer
);
997 #ifdef CONFIG_TRACER_MAX_TRACE
998 if (type
->use_max_tr
) {
999 tr
->allocated_snapshot
= false;
1001 /* Shrink the max buffer again */
1002 if (ring_buffer_expanded
)
1003 ring_buffer_resize(tr
->max_buffer
.buffer
, 1,
1004 RING_BUFFER_ALL_CPUS
);
1008 printk(KERN_CONT
"PASSED\n");
1012 static inline int run_tracer_selftest(struct tracer
*type
)
1016 #endif /* CONFIG_FTRACE_STARTUP_TEST */
1019 * register_tracer - register a tracer with the ftrace system.
1020 * @type - the plugin for the tracer
1022 * Register a new plugin tracer.
1024 int register_tracer(struct tracer
*type
)
1030 pr_info("Tracer must have a name\n");
1034 if (strlen(type
->name
) >= MAX_TRACER_SIZE
) {
1035 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE
);
1039 mutex_lock(&trace_types_lock
);
1041 tracing_selftest_running
= true;
1043 for (t
= trace_types
; t
; t
= t
->next
) {
1044 if (strcmp(type
->name
, t
->name
) == 0) {
1046 pr_info("Tracer %s already registered\n",
1053 if (!type
->set_flag
)
1054 type
->set_flag
= &dummy_set_flag
;
1056 type
->flags
= &dummy_tracer_flags
;
1058 if (!type
->flags
->opts
)
1059 type
->flags
->opts
= dummy_tracer_opt
;
1060 if (!type
->wait_pipe
)
1061 type
->wait_pipe
= default_wait_pipe
;
1063 ret
= run_tracer_selftest(type
);
1067 type
->next
= trace_types
;
1071 tracing_selftest_running
= false;
1072 mutex_unlock(&trace_types_lock
);
1074 if (ret
|| !default_bootup_tracer
)
1077 if (strncmp(default_bootup_tracer
, type
->name
, MAX_TRACER_SIZE
))
1080 printk(KERN_INFO
"Starting tracer '%s'\n", type
->name
);
1081 /* Do we want this tracer to start on bootup? */
1082 tracing_set_tracer(type
->name
);
1083 default_bootup_tracer
= NULL
;
1084 /* disable other selftests, since this will break it. */
1085 tracing_selftest_disabled
= true;
1086 #ifdef CONFIG_FTRACE_STARTUP_TEST
1087 printk(KERN_INFO
"Disabling FTRACE selftests due to running tracer '%s'\n",
1095 void tracing_reset(struct trace_buffer
*buf
, int cpu
)
1097 struct ring_buffer
*buffer
= buf
->buffer
;
1102 ring_buffer_record_disable(buffer
);
1104 /* Make sure all commits have finished */
1105 synchronize_sched();
1106 ring_buffer_reset_cpu(buffer
, cpu
);
1108 ring_buffer_record_enable(buffer
);
1111 void tracing_reset_online_cpus(struct trace_buffer
*buf
)
1113 struct ring_buffer
*buffer
= buf
->buffer
;
1119 ring_buffer_record_disable(buffer
);
1121 /* Make sure all commits have finished */
1122 synchronize_sched();
1124 buf
->time_start
= ftrace_now(buf
->cpu
);
1126 for_each_online_cpu(cpu
)
1127 ring_buffer_reset_cpu(buffer
, cpu
);
1129 ring_buffer_record_enable(buffer
);
1132 void tracing_reset_current(int cpu
)
1134 tracing_reset(&global_trace
.trace_buffer
, cpu
);
1137 void tracing_reset_all_online_cpus(void)
1139 struct trace_array
*tr
;
1141 mutex_lock(&trace_types_lock
);
1142 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
1143 tracing_reset_online_cpus(&tr
->trace_buffer
);
1144 #ifdef CONFIG_TRACER_MAX_TRACE
1145 tracing_reset_online_cpus(&tr
->max_buffer
);
1148 mutex_unlock(&trace_types_lock
);
1151 #define SAVED_CMDLINES 128
1152 #define NO_CMDLINE_MAP UINT_MAX
1153 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
1154 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
1155 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
1156 static int cmdline_idx
;
1157 static arch_spinlock_t trace_cmdline_lock
= __ARCH_SPIN_LOCK_UNLOCKED
;
1159 /* temporary disable recording */
1160 static atomic_t trace_record_cmdline_disabled __read_mostly
;
1162 static void trace_init_cmdlines(void)
1164 memset(&map_pid_to_cmdline
, NO_CMDLINE_MAP
, sizeof(map_pid_to_cmdline
));
1165 memset(&map_cmdline_to_pid
, NO_CMDLINE_MAP
, sizeof(map_cmdline_to_pid
));
1169 int is_tracing_stopped(void)
1171 return global_trace
.stop_count
;
1175 * ftrace_off_permanent - disable all ftrace code permanently
1177 * This should only be called when a serious anomally has
1178 * been detected. This will turn off the function tracing,
1179 * ring buffers, and other tracing utilites. It takes no
1180 * locks and can be called from any context.
1182 void ftrace_off_permanent(void)
1184 tracing_disabled
= 1;
1186 tracing_off_permanent();
1190 * tracing_start - quick start of the tracer
1192 * If tracing is enabled but was stopped by tracing_stop,
1193 * this will start the tracer back up.
1195 void tracing_start(void)
1197 struct ring_buffer
*buffer
;
1198 unsigned long flags
;
1200 if (tracing_disabled
)
1203 raw_spin_lock_irqsave(&global_trace
.start_lock
, flags
);
1204 if (--global_trace
.stop_count
) {
1205 if (global_trace
.stop_count
< 0) {
1206 /* Someone screwed up their debugging */
1208 global_trace
.stop_count
= 0;
1213 /* Prevent the buffers from switching */
1214 arch_spin_lock(&ftrace_max_lock
);
1216 buffer
= global_trace
.trace_buffer
.buffer
;
1218 ring_buffer_record_enable(buffer
);
1220 #ifdef CONFIG_TRACER_MAX_TRACE
1221 buffer
= global_trace
.max_buffer
.buffer
;
1223 ring_buffer_record_enable(buffer
);
1226 arch_spin_unlock(&ftrace_max_lock
);
1230 raw_spin_unlock_irqrestore(&global_trace
.start_lock
, flags
);
1233 static void tracing_start_tr(struct trace_array
*tr
)
1235 struct ring_buffer
*buffer
;
1236 unsigned long flags
;
1238 if (tracing_disabled
)
1241 /* If global, we need to also start the max tracer */
1242 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
1243 return tracing_start();
1245 raw_spin_lock_irqsave(&tr
->start_lock
, flags
);
1247 if (--tr
->stop_count
) {
1248 if (tr
->stop_count
< 0) {
1249 /* Someone screwed up their debugging */
1256 buffer
= tr
->trace_buffer
.buffer
;
1258 ring_buffer_record_enable(buffer
);
1261 raw_spin_unlock_irqrestore(&tr
->start_lock
, flags
);
1265 * tracing_stop - quick stop of the tracer
1267 * Light weight way to stop tracing. Use in conjunction with
1270 void tracing_stop(void)
1272 struct ring_buffer
*buffer
;
1273 unsigned long flags
;
1276 raw_spin_lock_irqsave(&global_trace
.start_lock
, flags
);
1277 if (global_trace
.stop_count
++)
1280 /* Prevent the buffers from switching */
1281 arch_spin_lock(&ftrace_max_lock
);
1283 buffer
= global_trace
.trace_buffer
.buffer
;
1285 ring_buffer_record_disable(buffer
);
1287 #ifdef CONFIG_TRACER_MAX_TRACE
1288 buffer
= global_trace
.max_buffer
.buffer
;
1290 ring_buffer_record_disable(buffer
);
1293 arch_spin_unlock(&ftrace_max_lock
);
1296 raw_spin_unlock_irqrestore(&global_trace
.start_lock
, flags
);
1299 static void tracing_stop_tr(struct trace_array
*tr
)
1301 struct ring_buffer
*buffer
;
1302 unsigned long flags
;
1304 /* If global, we need to also stop the max tracer */
1305 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
1306 return tracing_stop();
1308 raw_spin_lock_irqsave(&tr
->start_lock
, flags
);
1309 if (tr
->stop_count
++)
1312 buffer
= tr
->trace_buffer
.buffer
;
1314 ring_buffer_record_disable(buffer
);
1317 raw_spin_unlock_irqrestore(&tr
->start_lock
, flags
);
1320 void trace_stop_cmdline_recording(void);
1322 static void trace_save_cmdline(struct task_struct
*tsk
)
1326 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
1330 * It's not the end of the world if we don't get
1331 * the lock, but we also don't want to spin
1332 * nor do we want to disable interrupts,
1333 * so if we miss here, then better luck next time.
1335 if (!arch_spin_trylock(&trace_cmdline_lock
))
1338 idx
= map_pid_to_cmdline
[tsk
->pid
];
1339 if (idx
== NO_CMDLINE_MAP
) {
1340 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
1343 * Check whether the cmdline buffer at idx has a pid
1344 * mapped. We are going to overwrite that entry so we
1345 * need to clear the map_pid_to_cmdline. Otherwise we
1346 * would read the new comm for the old pid.
1348 pid
= map_cmdline_to_pid
[idx
];
1349 if (pid
!= NO_CMDLINE_MAP
)
1350 map_pid_to_cmdline
[pid
] = NO_CMDLINE_MAP
;
1352 map_cmdline_to_pid
[idx
] = tsk
->pid
;
1353 map_pid_to_cmdline
[tsk
->pid
] = idx
;
1358 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
1360 arch_spin_unlock(&trace_cmdline_lock
);
1363 void trace_find_cmdline(int pid
, char comm
[])
1368 strcpy(comm
, "<idle>");
1372 if (WARN_ON_ONCE(pid
< 0)) {
1373 strcpy(comm
, "<XXX>");
1377 if (pid
> PID_MAX_DEFAULT
) {
1378 strcpy(comm
, "<...>");
1383 arch_spin_lock(&trace_cmdline_lock
);
1384 map
= map_pid_to_cmdline
[pid
];
1385 if (map
!= NO_CMDLINE_MAP
)
1386 strcpy(comm
, saved_cmdlines
[map
]);
1388 strcpy(comm
, "<...>");
1390 arch_spin_unlock(&trace_cmdline_lock
);
1394 void tracing_record_cmdline(struct task_struct
*tsk
)
1396 if (atomic_read(&trace_record_cmdline_disabled
) || !tracing_is_on())
1399 if (!__this_cpu_read(trace_cmdline_save
))
1402 __this_cpu_write(trace_cmdline_save
, false);
1404 trace_save_cmdline(tsk
);
1408 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
,
1411 struct task_struct
*tsk
= current
;
1413 entry
->preempt_count
= pc
& 0xff;
1414 entry
->pid
= (tsk
) ? tsk
->pid
: 0;
1416 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1417 (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
1419 TRACE_FLAG_IRQS_NOSUPPORT
|
1421 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
1422 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
1423 (need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0);
1425 EXPORT_SYMBOL_GPL(tracing_generic_entry_update
);
1427 struct ring_buffer_event
*
1428 trace_buffer_lock_reserve(struct ring_buffer
*buffer
,
1431 unsigned long flags
, int pc
)
1433 struct ring_buffer_event
*event
;
1435 event
= ring_buffer_lock_reserve(buffer
, len
);
1436 if (event
!= NULL
) {
1437 struct trace_entry
*ent
= ring_buffer_event_data(event
);
1439 tracing_generic_entry_update(ent
, flags
, pc
);
1447 __buffer_unlock_commit(struct ring_buffer
*buffer
, struct ring_buffer_event
*event
)
1449 __this_cpu_write(trace_cmdline_save
, true);
1450 ring_buffer_unlock_commit(buffer
, event
);
1454 __trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1455 struct ring_buffer_event
*event
,
1456 unsigned long flags
, int pc
)
1458 __buffer_unlock_commit(buffer
, event
);
1460 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1461 ftrace_trace_userstack(buffer
, flags
, pc
);
1464 void trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1465 struct ring_buffer_event
*event
,
1466 unsigned long flags
, int pc
)
1468 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
);
1470 EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit
);
1472 struct ring_buffer_event
*
1473 trace_event_buffer_lock_reserve(struct ring_buffer
**current_rb
,
1474 struct ftrace_event_file
*ftrace_file
,
1475 int type
, unsigned long len
,
1476 unsigned long flags
, int pc
)
1478 *current_rb
= ftrace_file
->tr
->trace_buffer
.buffer
;
1479 return trace_buffer_lock_reserve(*current_rb
,
1480 type
, len
, flags
, pc
);
1482 EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve
);
1484 struct ring_buffer_event
*
1485 trace_current_buffer_lock_reserve(struct ring_buffer
**current_rb
,
1486 int type
, unsigned long len
,
1487 unsigned long flags
, int pc
)
1489 *current_rb
= global_trace
.trace_buffer
.buffer
;
1490 return trace_buffer_lock_reserve(*current_rb
,
1491 type
, len
, flags
, pc
);
1493 EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve
);
1495 void trace_current_buffer_unlock_commit(struct ring_buffer
*buffer
,
1496 struct ring_buffer_event
*event
,
1497 unsigned long flags
, int pc
)
1499 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
);
1501 EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit
);
1503 void trace_buffer_unlock_commit_regs(struct ring_buffer
*buffer
,
1504 struct ring_buffer_event
*event
,
1505 unsigned long flags
, int pc
,
1506 struct pt_regs
*regs
)
1508 __buffer_unlock_commit(buffer
, event
);
1510 ftrace_trace_stack_regs(buffer
, flags
, 0, pc
, regs
);
1511 ftrace_trace_userstack(buffer
, flags
, pc
);
1513 EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit_regs
);
1515 void trace_current_buffer_discard_commit(struct ring_buffer
*buffer
,
1516 struct ring_buffer_event
*event
)
1518 ring_buffer_discard_commit(buffer
, event
);
1520 EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit
);
1523 trace_function(struct trace_array
*tr
,
1524 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
1527 struct ftrace_event_call
*call
= &event_function
;
1528 struct ring_buffer
*buffer
= tr
->trace_buffer
.buffer
;
1529 struct ring_buffer_event
*event
;
1530 struct ftrace_entry
*entry
;
1532 /* If we are reading the ring buffer, don't trace */
1533 if (unlikely(__this_cpu_read(ftrace_cpu_disabled
)))
1536 event
= trace_buffer_lock_reserve(buffer
, TRACE_FN
, sizeof(*entry
),
1540 entry
= ring_buffer_event_data(event
);
1542 entry
->parent_ip
= parent_ip
;
1544 if (!filter_check_discard(call
, entry
, buffer
, event
))
1545 __buffer_unlock_commit(buffer
, event
);
1549 ftrace(struct trace_array
*tr
, struct trace_array_cpu
*data
,
1550 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
1553 if (likely(!atomic_read(&data
->disabled
)))
1554 trace_function(tr
, ip
, parent_ip
, flags
, pc
);
1557 #ifdef CONFIG_STACKTRACE
1559 #define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
1560 struct ftrace_stack
{
1561 unsigned long calls
[FTRACE_STACK_MAX_ENTRIES
];
1564 static DEFINE_PER_CPU(struct ftrace_stack
, ftrace_stack
);
1565 static DEFINE_PER_CPU(int, ftrace_stack_reserve
);
1567 static void __ftrace_trace_stack(struct ring_buffer
*buffer
,
1568 unsigned long flags
,
1569 int skip
, int pc
, struct pt_regs
*regs
)
1571 struct ftrace_event_call
*call
= &event_kernel_stack
;
1572 struct ring_buffer_event
*event
;
1573 struct stack_entry
*entry
;
1574 struct stack_trace trace
;
1576 int size
= FTRACE_STACK_ENTRIES
;
1578 trace
.nr_entries
= 0;
1582 * Since events can happen in NMIs there's no safe way to
1583 * use the per cpu ftrace_stacks. We reserve it and if an interrupt
1584 * or NMI comes in, it will just have to use the default
1585 * FTRACE_STACK_SIZE.
1587 preempt_disable_notrace();
1589 use_stack
= __this_cpu_inc_return(ftrace_stack_reserve
);
1591 * We don't need any atomic variables, just a barrier.
1592 * If an interrupt comes in, we don't care, because it would
1593 * have exited and put the counter back to what we want.
1594 * We just need a barrier to keep gcc from moving things
1598 if (use_stack
== 1) {
1599 trace
.entries
= &__get_cpu_var(ftrace_stack
).calls
[0];
1600 trace
.max_entries
= FTRACE_STACK_MAX_ENTRIES
;
1603 save_stack_trace_regs(regs
, &trace
);
1605 save_stack_trace(&trace
);
1607 if (trace
.nr_entries
> size
)
1608 size
= trace
.nr_entries
;
1610 /* From now on, use_stack is a boolean */
1613 size
*= sizeof(unsigned long);
1615 event
= trace_buffer_lock_reserve(buffer
, TRACE_STACK
,
1616 sizeof(*entry
) + size
, flags
, pc
);
1619 entry
= ring_buffer_event_data(event
);
1621 memset(&entry
->caller
, 0, size
);
1624 memcpy(&entry
->caller
, trace
.entries
,
1625 trace
.nr_entries
* sizeof(unsigned long));
1627 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1628 trace
.entries
= entry
->caller
;
1630 save_stack_trace_regs(regs
, &trace
);
1632 save_stack_trace(&trace
);
1635 entry
->size
= trace
.nr_entries
;
1637 if (!filter_check_discard(call
, entry
, buffer
, event
))
1638 __buffer_unlock_commit(buffer
, event
);
1641 /* Again, don't let gcc optimize things here */
1643 __this_cpu_dec(ftrace_stack_reserve
);
1644 preempt_enable_notrace();
1648 void ftrace_trace_stack_regs(struct ring_buffer
*buffer
, unsigned long flags
,
1649 int skip
, int pc
, struct pt_regs
*regs
)
1651 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1654 __ftrace_trace_stack(buffer
, flags
, skip
, pc
, regs
);
1657 void ftrace_trace_stack(struct ring_buffer
*buffer
, unsigned long flags
,
1660 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1663 __ftrace_trace_stack(buffer
, flags
, skip
, pc
, NULL
);
1666 void __trace_stack(struct trace_array
*tr
, unsigned long flags
, int skip
,
1669 __ftrace_trace_stack(tr
->trace_buffer
.buffer
, flags
, skip
, pc
, NULL
);
1673 * trace_dump_stack - record a stack back trace in the trace buffer
1674 * @skip: Number of functions to skip (helper handlers)
1676 void trace_dump_stack(int skip
)
1678 unsigned long flags
;
1680 if (tracing_disabled
|| tracing_selftest_running
)
1683 local_save_flags(flags
);
1686 * Skip 3 more, seems to get us at the caller of
1690 __ftrace_trace_stack(global_trace
.trace_buffer
.buffer
,
1691 flags
, skip
, preempt_count(), NULL
);
1694 static DEFINE_PER_CPU(int, user_stack_count
);
1697 ftrace_trace_userstack(struct ring_buffer
*buffer
, unsigned long flags
, int pc
)
1699 struct ftrace_event_call
*call
= &event_user_stack
;
1700 struct ring_buffer_event
*event
;
1701 struct userstack_entry
*entry
;
1702 struct stack_trace trace
;
1704 if (!(trace_flags
& TRACE_ITER_USERSTACKTRACE
))
1708 * NMIs can not handle page faults, even with fix ups.
1709 * The save user stack can (and often does) fault.
1711 if (unlikely(in_nmi()))
1715 * prevent recursion, since the user stack tracing may
1716 * trigger other kernel events.
1719 if (__this_cpu_read(user_stack_count
))
1722 __this_cpu_inc(user_stack_count
);
1724 event
= trace_buffer_lock_reserve(buffer
, TRACE_USER_STACK
,
1725 sizeof(*entry
), flags
, pc
);
1727 goto out_drop_count
;
1728 entry
= ring_buffer_event_data(event
);
1730 entry
->tgid
= current
->tgid
;
1731 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
1733 trace
.nr_entries
= 0;
1734 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1736 trace
.entries
= entry
->caller
;
1738 save_stack_trace_user(&trace
);
1739 if (!filter_check_discard(call
, entry
, buffer
, event
))
1740 __buffer_unlock_commit(buffer
, event
);
1743 __this_cpu_dec(user_stack_count
);
1749 static void __trace_userstack(struct trace_array
*tr
, unsigned long flags
)
1751 ftrace_trace_userstack(tr
, flags
, preempt_count());
1755 #endif /* CONFIG_STACKTRACE */
1757 /* created for use with alloc_percpu */
1758 struct trace_buffer_struct
{
1759 char buffer
[TRACE_BUF_SIZE
];
1762 static struct trace_buffer_struct
*trace_percpu_buffer
;
1763 static struct trace_buffer_struct
*trace_percpu_sirq_buffer
;
1764 static struct trace_buffer_struct
*trace_percpu_irq_buffer
;
1765 static struct trace_buffer_struct
*trace_percpu_nmi_buffer
;
1768 * The buffer used is dependent on the context. There is a per cpu
1769 * buffer for normal context, softirq contex, hard irq context and
1770 * for NMI context. Thise allows for lockless recording.
1772 * Note, if the buffers failed to be allocated, then this returns NULL
1774 static char *get_trace_buf(void)
1776 struct trace_buffer_struct
*percpu_buffer
;
1779 * If we have allocated per cpu buffers, then we do not
1780 * need to do any locking.
1783 percpu_buffer
= trace_percpu_nmi_buffer
;
1785 percpu_buffer
= trace_percpu_irq_buffer
;
1786 else if (in_softirq())
1787 percpu_buffer
= trace_percpu_sirq_buffer
;
1789 percpu_buffer
= trace_percpu_buffer
;
1794 return this_cpu_ptr(&percpu_buffer
->buffer
[0]);
1797 static int alloc_percpu_trace_buffer(void)
1799 struct trace_buffer_struct
*buffers
;
1800 struct trace_buffer_struct
*sirq_buffers
;
1801 struct trace_buffer_struct
*irq_buffers
;
1802 struct trace_buffer_struct
*nmi_buffers
;
1804 buffers
= alloc_percpu(struct trace_buffer_struct
);
1808 sirq_buffers
= alloc_percpu(struct trace_buffer_struct
);
1812 irq_buffers
= alloc_percpu(struct trace_buffer_struct
);
1816 nmi_buffers
= alloc_percpu(struct trace_buffer_struct
);
1820 trace_percpu_buffer
= buffers
;
1821 trace_percpu_sirq_buffer
= sirq_buffers
;
1822 trace_percpu_irq_buffer
= irq_buffers
;
1823 trace_percpu_nmi_buffer
= nmi_buffers
;
1828 free_percpu(irq_buffers
);
1830 free_percpu(sirq_buffers
);
1832 free_percpu(buffers
);
1834 WARN(1, "Could not allocate percpu trace_printk buffer");
1838 static int buffers_allocated
;
1840 void trace_printk_init_buffers(void)
1842 if (buffers_allocated
)
1845 if (alloc_percpu_trace_buffer())
1848 pr_info("ftrace: Allocated trace_printk buffers\n");
1850 /* Expand the buffers to set size */
1851 tracing_update_buffers();
1853 buffers_allocated
= 1;
1856 * trace_printk_init_buffers() can be called by modules.
1857 * If that happens, then we need to start cmdline recording
1858 * directly here. If the global_trace.buffer is already
1859 * allocated here, then this was called by module code.
1861 if (global_trace
.trace_buffer
.buffer
)
1862 tracing_start_cmdline_record();
1865 void trace_printk_start_comm(void)
1867 /* Start tracing comms if trace printk is set */
1868 if (!buffers_allocated
)
1870 tracing_start_cmdline_record();
1873 static void trace_printk_start_stop_comm(int enabled
)
1875 if (!buffers_allocated
)
1879 tracing_start_cmdline_record();
1881 tracing_stop_cmdline_record();
1885 * trace_vbprintk - write binary msg to tracing buffer
1888 int trace_vbprintk(unsigned long ip
, const char *fmt
, va_list args
)
1890 struct ftrace_event_call
*call
= &event_bprint
;
1891 struct ring_buffer_event
*event
;
1892 struct ring_buffer
*buffer
;
1893 struct trace_array
*tr
= &global_trace
;
1894 struct bprint_entry
*entry
;
1895 unsigned long flags
;
1897 int len
= 0, size
, pc
;
1899 if (unlikely(tracing_selftest_running
|| tracing_disabled
))
1902 /* Don't pollute graph traces with trace_vprintk internals */
1903 pause_graph_tracing();
1905 pc
= preempt_count();
1906 preempt_disable_notrace();
1908 tbuffer
= get_trace_buf();
1914 len
= vbin_printf((u32
*)tbuffer
, TRACE_BUF_SIZE
/sizeof(int), fmt
, args
);
1916 if (len
> TRACE_BUF_SIZE
/sizeof(int) || len
< 0)
1919 local_save_flags(flags
);
1920 size
= sizeof(*entry
) + sizeof(u32
) * len
;
1921 buffer
= tr
->trace_buffer
.buffer
;
1922 event
= trace_buffer_lock_reserve(buffer
, TRACE_BPRINT
, size
,
1926 entry
= ring_buffer_event_data(event
);
1930 memcpy(entry
->buf
, tbuffer
, sizeof(u32
) * len
);
1931 if (!filter_check_discard(call
, entry
, buffer
, event
)) {
1932 __buffer_unlock_commit(buffer
, event
);
1933 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1937 preempt_enable_notrace();
1938 unpause_graph_tracing();
1942 EXPORT_SYMBOL_GPL(trace_vbprintk
);
1945 __trace_array_vprintk(struct ring_buffer
*buffer
,
1946 unsigned long ip
, const char *fmt
, va_list args
)
1948 struct ftrace_event_call
*call
= &event_print
;
1949 struct ring_buffer_event
*event
;
1950 int len
= 0, size
, pc
;
1951 struct print_entry
*entry
;
1952 unsigned long flags
;
1955 if (tracing_disabled
|| tracing_selftest_running
)
1958 /* Don't pollute graph traces with trace_vprintk internals */
1959 pause_graph_tracing();
1961 pc
= preempt_count();
1962 preempt_disable_notrace();
1965 tbuffer
= get_trace_buf();
1971 len
= vsnprintf(tbuffer
, TRACE_BUF_SIZE
, fmt
, args
);
1972 if (len
> TRACE_BUF_SIZE
)
1975 local_save_flags(flags
);
1976 size
= sizeof(*entry
) + len
+ 1;
1977 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, size
,
1981 entry
= ring_buffer_event_data(event
);
1984 memcpy(&entry
->buf
, tbuffer
, len
);
1985 entry
->buf
[len
] = '\0';
1986 if (!filter_check_discard(call
, entry
, buffer
, event
)) {
1987 __buffer_unlock_commit(buffer
, event
);
1988 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1991 preempt_enable_notrace();
1992 unpause_graph_tracing();
1997 int trace_array_vprintk(struct trace_array
*tr
,
1998 unsigned long ip
, const char *fmt
, va_list args
)
2000 return __trace_array_vprintk(tr
->trace_buffer
.buffer
, ip
, fmt
, args
);
2003 int trace_array_printk(struct trace_array
*tr
,
2004 unsigned long ip
, const char *fmt
, ...)
2009 if (!(trace_flags
& TRACE_ITER_PRINTK
))
2013 ret
= trace_array_vprintk(tr
, ip
, fmt
, ap
);
2018 int trace_array_printk_buf(struct ring_buffer
*buffer
,
2019 unsigned long ip
, const char *fmt
, ...)
2024 if (!(trace_flags
& TRACE_ITER_PRINTK
))
2028 ret
= __trace_array_vprintk(buffer
, ip
, fmt
, ap
);
2033 int trace_vprintk(unsigned long ip
, const char *fmt
, va_list args
)
2035 return trace_array_vprintk(&global_trace
, ip
, fmt
, args
);
2037 EXPORT_SYMBOL_GPL(trace_vprintk
);
2039 static void trace_iterator_increment(struct trace_iterator
*iter
)
2041 struct ring_buffer_iter
*buf_iter
= trace_buffer_iter(iter
, iter
->cpu
);
2045 ring_buffer_read(buf_iter
, NULL
);
2048 static struct trace_entry
*
2049 peek_next_entry(struct trace_iterator
*iter
, int cpu
, u64
*ts
,
2050 unsigned long *lost_events
)
2052 struct ring_buffer_event
*event
;
2053 struct ring_buffer_iter
*buf_iter
= trace_buffer_iter(iter
, cpu
);
2056 event
= ring_buffer_iter_peek(buf_iter
, ts
);
2058 event
= ring_buffer_peek(iter
->trace_buffer
->buffer
, cpu
, ts
,
2062 iter
->ent_size
= ring_buffer_event_length(event
);
2063 return ring_buffer_event_data(event
);
2069 static struct trace_entry
*
2070 __find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
,
2071 unsigned long *missing_events
, u64
*ent_ts
)
2073 struct ring_buffer
*buffer
= iter
->trace_buffer
->buffer
;
2074 struct trace_entry
*ent
, *next
= NULL
;
2075 unsigned long lost_events
= 0, next_lost
= 0;
2076 int cpu_file
= iter
->cpu_file
;
2077 u64 next_ts
= 0, ts
;
2083 * If we are in a per_cpu trace file, don't bother by iterating over
2084 * all cpu and peek directly.
2086 if (cpu_file
> RING_BUFFER_ALL_CPUS
) {
2087 if (ring_buffer_empty_cpu(buffer
, cpu_file
))
2089 ent
= peek_next_entry(iter
, cpu_file
, ent_ts
, missing_events
);
2091 *ent_cpu
= cpu_file
;
2096 for_each_tracing_cpu(cpu
) {
2098 if (ring_buffer_empty_cpu(buffer
, cpu
))
2101 ent
= peek_next_entry(iter
, cpu
, &ts
, &lost_events
);
2104 * Pick the entry with the smallest timestamp:
2106 if (ent
&& (!next
|| ts
< next_ts
)) {
2110 next_lost
= lost_events
;
2111 next_size
= iter
->ent_size
;
2115 iter
->ent_size
= next_size
;
2118 *ent_cpu
= next_cpu
;
2124 *missing_events
= next_lost
;
2129 /* Find the next real entry, without updating the iterator itself */
2130 struct trace_entry
*trace_find_next_entry(struct trace_iterator
*iter
,
2131 int *ent_cpu
, u64
*ent_ts
)
2133 return __find_next_entry(iter
, ent_cpu
, NULL
, ent_ts
);
2136 /* Find the next real entry, and increment the iterator to the next entry */
2137 void *trace_find_next_entry_inc(struct trace_iterator
*iter
)
2139 iter
->ent
= __find_next_entry(iter
, &iter
->cpu
,
2140 &iter
->lost_events
, &iter
->ts
);
2143 trace_iterator_increment(iter
);
2145 return iter
->ent
? iter
: NULL
;
2148 static void trace_consume(struct trace_iterator
*iter
)
2150 ring_buffer_consume(iter
->trace_buffer
->buffer
, iter
->cpu
, &iter
->ts
,
2151 &iter
->lost_events
);
2154 static void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
2156 struct trace_iterator
*iter
= m
->private;
2160 WARN_ON_ONCE(iter
->leftover
);
2164 /* can't go backwards */
2169 ent
= trace_find_next_entry_inc(iter
);
2173 while (ent
&& iter
->idx
< i
)
2174 ent
= trace_find_next_entry_inc(iter
);
2181 void tracing_iter_reset(struct trace_iterator
*iter
, int cpu
)
2183 struct ring_buffer_event
*event
;
2184 struct ring_buffer_iter
*buf_iter
;
2185 unsigned long entries
= 0;
2188 per_cpu_ptr(iter
->trace_buffer
->data
, cpu
)->skipped_entries
= 0;
2190 buf_iter
= trace_buffer_iter(iter
, cpu
);
2194 ring_buffer_iter_reset(buf_iter
);
2197 * We could have the case with the max latency tracers
2198 * that a reset never took place on a cpu. This is evident
2199 * by the timestamp being before the start of the buffer.
2201 while ((event
= ring_buffer_iter_peek(buf_iter
, &ts
))) {
2202 if (ts
>= iter
->trace_buffer
->time_start
)
2205 ring_buffer_read(buf_iter
, NULL
);
2208 per_cpu_ptr(iter
->trace_buffer
->data
, cpu
)->skipped_entries
= entries
;
2212 * The current tracer is copied to avoid a global locking
2215 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
2217 struct trace_iterator
*iter
= m
->private;
2218 struct trace_array
*tr
= iter
->tr
;
2219 int cpu_file
= iter
->cpu_file
;
2225 * copy the tracer to avoid using a global lock all around.
2226 * iter->trace is a copy of current_trace, the pointer to the
2227 * name may be used instead of a strcmp(), as iter->trace->name
2228 * will point to the same string as current_trace->name.
2230 mutex_lock(&trace_types_lock
);
2231 if (unlikely(tr
->current_trace
&& iter
->trace
->name
!= tr
->current_trace
->name
))
2232 *iter
->trace
= *tr
->current_trace
;
2233 mutex_unlock(&trace_types_lock
);
2235 #ifdef CONFIG_TRACER_MAX_TRACE
2236 if (iter
->snapshot
&& iter
->trace
->use_max_tr
)
2237 return ERR_PTR(-EBUSY
);
2240 if (!iter
->snapshot
)
2241 atomic_inc(&trace_record_cmdline_disabled
);
2243 if (*pos
!= iter
->pos
) {
2248 if (cpu_file
== RING_BUFFER_ALL_CPUS
) {
2249 for_each_tracing_cpu(cpu
)
2250 tracing_iter_reset(iter
, cpu
);
2252 tracing_iter_reset(iter
, cpu_file
);
2255 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
2260 * If we overflowed the seq_file before, then we want
2261 * to just reuse the trace_seq buffer again.
2267 p
= s_next(m
, p
, &l
);
2271 trace_event_read_lock();
2272 trace_access_lock(cpu_file
);
2276 static void s_stop(struct seq_file
*m
, void *p
)
2278 struct trace_iterator
*iter
= m
->private;
2280 #ifdef CONFIG_TRACER_MAX_TRACE
2281 if (iter
->snapshot
&& iter
->trace
->use_max_tr
)
2285 if (!iter
->snapshot
)
2286 atomic_dec(&trace_record_cmdline_disabled
);
2288 trace_access_unlock(iter
->cpu_file
);
2289 trace_event_read_unlock();
2293 get_total_entries(struct trace_buffer
*buf
,
2294 unsigned long *total
, unsigned long *entries
)
2296 unsigned long count
;
2302 for_each_tracing_cpu(cpu
) {
2303 count
= ring_buffer_entries_cpu(buf
->buffer
, cpu
);
2305 * If this buffer has skipped entries, then we hold all
2306 * entries for the trace and we need to ignore the
2307 * ones before the time stamp.
2309 if (per_cpu_ptr(buf
->data
, cpu
)->skipped_entries
) {
2310 count
-= per_cpu_ptr(buf
->data
, cpu
)->skipped_entries
;
2311 /* total is the same as the entries */
2315 ring_buffer_overrun_cpu(buf
->buffer
, cpu
);
2320 static void print_lat_help_header(struct seq_file
*m
)
2322 seq_puts(m
, "# _------=> CPU# \n");
2323 seq_puts(m
, "# / _-----=> irqs-off \n");
2324 seq_puts(m
, "# | / _----=> need-resched \n");
2325 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
2326 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
2327 seq_puts(m
, "# |||| / delay \n");
2328 seq_puts(m
, "# cmd pid ||||| time | caller \n");
2329 seq_puts(m
, "# \\ / ||||| \\ | / \n");
2332 static void print_event_info(struct trace_buffer
*buf
, struct seq_file
*m
)
2334 unsigned long total
;
2335 unsigned long entries
;
2337 get_total_entries(buf
, &total
, &entries
);
2338 seq_printf(m
, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
2339 entries
, total
, num_online_cpus());
2343 static void print_func_help_header(struct trace_buffer
*buf
, struct seq_file
*m
)
2345 print_event_info(buf
, m
);
2346 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
2347 seq_puts(m
, "# | | | | |\n");
2350 static void print_func_help_header_irq(struct trace_buffer
*buf
, struct seq_file
*m
)
2352 print_event_info(buf
, m
);
2353 seq_puts(m
, "# _-----=> irqs-off\n");
2354 seq_puts(m
, "# / _----=> need-resched\n");
2355 seq_puts(m
, "# | / _---=> hardirq/softirq\n");
2356 seq_puts(m
, "# || / _--=> preempt-depth\n");
2357 seq_puts(m
, "# ||| / delay\n");
2358 seq_puts(m
, "# TASK-PID CPU# |||| TIMESTAMP FUNCTION\n");
2359 seq_puts(m
, "# | | | |||| | |\n");
2363 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
2365 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
2366 struct trace_buffer
*buf
= iter
->trace_buffer
;
2367 struct trace_array_cpu
*data
= per_cpu_ptr(buf
->data
, buf
->cpu
);
2368 struct tracer
*type
= iter
->trace
;
2369 unsigned long entries
;
2370 unsigned long total
;
2371 const char *name
= "preemption";
2375 get_total_entries(buf
, &total
, &entries
);
2377 seq_printf(m
, "# %s latency trace v1.1.5 on %s\n",
2379 seq_puts(m
, "# -----------------------------------"
2380 "---------------------------------\n");
2381 seq_printf(m
, "# latency: %lu us, #%lu/%lu, CPU#%d |"
2382 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
2383 nsecs_to_usecs(data
->saved_latency
),
2387 #if defined(CONFIG_PREEMPT_NONE)
2389 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
2391 #elif defined(CONFIG_PREEMPT)
2396 /* These are reserved for later use */
2399 seq_printf(m
, " #P:%d)\n", num_online_cpus());
2403 seq_puts(m
, "# -----------------\n");
2404 seq_printf(m
, "# | task: %.16s-%d "
2405 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
2406 data
->comm
, data
->pid
,
2407 from_kuid_munged(seq_user_ns(m
), data
->uid
), data
->nice
,
2408 data
->policy
, data
->rt_priority
);
2409 seq_puts(m
, "# -----------------\n");
2411 if (data
->critical_start
) {
2412 seq_puts(m
, "# => started at: ");
2413 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
2414 trace_print_seq(m
, &iter
->seq
);
2415 seq_puts(m
, "\n# => ended at: ");
2416 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
2417 trace_print_seq(m
, &iter
->seq
);
2418 seq_puts(m
, "\n#\n");
2424 static void test_cpu_buff_start(struct trace_iterator
*iter
)
2426 struct trace_seq
*s
= &iter
->seq
;
2428 if (!(trace_flags
& TRACE_ITER_ANNOTATE
))
2431 if (!(iter
->iter_flags
& TRACE_FILE_ANNOTATE
))
2434 if (cpumask_test_cpu(iter
->cpu
, iter
->started
))
2437 if (per_cpu_ptr(iter
->trace_buffer
->data
, iter
->cpu
)->skipped_entries
)
2440 cpumask_set_cpu(iter
->cpu
, iter
->started
);
2442 /* Don't print started cpu buffer for the first entry of the trace */
2444 trace_seq_printf(s
, "##### CPU %u buffer started ####\n",
2448 static enum print_line_t
print_trace_fmt(struct trace_iterator
*iter
)
2450 struct trace_seq
*s
= &iter
->seq
;
2451 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
2452 struct trace_entry
*entry
;
2453 struct trace_event
*event
;
2457 test_cpu_buff_start(iter
);
2459 event
= ftrace_find_event(entry
->type
);
2461 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2462 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
2463 if (!trace_print_lat_context(iter
))
2466 if (!trace_print_context(iter
))
2472 return event
->funcs
->trace(iter
, sym_flags
, event
);
2474 if (!trace_seq_printf(s
, "Unknown type %d\n", entry
->type
))
2477 return TRACE_TYPE_HANDLED
;
2479 return TRACE_TYPE_PARTIAL_LINE
;
2482 static enum print_line_t
print_raw_fmt(struct trace_iterator
*iter
)
2484 struct trace_seq
*s
= &iter
->seq
;
2485 struct trace_entry
*entry
;
2486 struct trace_event
*event
;
2490 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2491 if (!trace_seq_printf(s
, "%d %d %llu ",
2492 entry
->pid
, iter
->cpu
, iter
->ts
))
2496 event
= ftrace_find_event(entry
->type
);
2498 return event
->funcs
->raw(iter
, 0, event
);
2500 if (!trace_seq_printf(s
, "%d ?\n", entry
->type
))
2503 return TRACE_TYPE_HANDLED
;
2505 return TRACE_TYPE_PARTIAL_LINE
;
2508 static enum print_line_t
print_hex_fmt(struct trace_iterator
*iter
)
2510 struct trace_seq
*s
= &iter
->seq
;
2511 unsigned char newline
= '\n';
2512 struct trace_entry
*entry
;
2513 struct trace_event
*event
;
2517 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2518 SEQ_PUT_HEX_FIELD_RET(s
, entry
->pid
);
2519 SEQ_PUT_HEX_FIELD_RET(s
, iter
->cpu
);
2520 SEQ_PUT_HEX_FIELD_RET(s
, iter
->ts
);
2523 event
= ftrace_find_event(entry
->type
);
2525 enum print_line_t ret
= event
->funcs
->hex(iter
, 0, event
);
2526 if (ret
!= TRACE_TYPE_HANDLED
)
2530 SEQ_PUT_FIELD_RET(s
, newline
);
2532 return TRACE_TYPE_HANDLED
;
2535 static enum print_line_t
print_bin_fmt(struct trace_iterator
*iter
)
2537 struct trace_seq
*s
= &iter
->seq
;
2538 struct trace_entry
*entry
;
2539 struct trace_event
*event
;
2543 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2544 SEQ_PUT_FIELD_RET(s
, entry
->pid
);
2545 SEQ_PUT_FIELD_RET(s
, iter
->cpu
);
2546 SEQ_PUT_FIELD_RET(s
, iter
->ts
);
2549 event
= ftrace_find_event(entry
->type
);
2550 return event
? event
->funcs
->binary(iter
, 0, event
) :
2554 int trace_empty(struct trace_iterator
*iter
)
2556 struct ring_buffer_iter
*buf_iter
;
2559 /* If we are looking at one CPU buffer, only check that one */
2560 if (iter
->cpu_file
!= RING_BUFFER_ALL_CPUS
) {
2561 cpu
= iter
->cpu_file
;
2562 buf_iter
= trace_buffer_iter(iter
, cpu
);
2564 if (!ring_buffer_iter_empty(buf_iter
))
2567 if (!ring_buffer_empty_cpu(iter
->trace_buffer
->buffer
, cpu
))
2573 for_each_tracing_cpu(cpu
) {
2574 buf_iter
= trace_buffer_iter(iter
, cpu
);
2576 if (!ring_buffer_iter_empty(buf_iter
))
2579 if (!ring_buffer_empty_cpu(iter
->trace_buffer
->buffer
, cpu
))
2587 /* Called with trace_event_read_lock() held. */
2588 enum print_line_t
print_trace_line(struct trace_iterator
*iter
)
2590 enum print_line_t ret
;
2592 if (iter
->lost_events
&&
2593 !trace_seq_printf(&iter
->seq
, "CPU:%d [LOST %lu EVENTS]\n",
2594 iter
->cpu
, iter
->lost_events
))
2595 return TRACE_TYPE_PARTIAL_LINE
;
2597 if (iter
->trace
&& iter
->trace
->print_line
) {
2598 ret
= iter
->trace
->print_line(iter
);
2599 if (ret
!= TRACE_TYPE_UNHANDLED
)
2603 if (iter
->ent
->type
== TRACE_BPUTS
&&
2604 trace_flags
& TRACE_ITER_PRINTK
&&
2605 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2606 return trace_print_bputs_msg_only(iter
);
2608 if (iter
->ent
->type
== TRACE_BPRINT
&&
2609 trace_flags
& TRACE_ITER_PRINTK
&&
2610 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2611 return trace_print_bprintk_msg_only(iter
);
2613 if (iter
->ent
->type
== TRACE_PRINT
&&
2614 trace_flags
& TRACE_ITER_PRINTK
&&
2615 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2616 return trace_print_printk_msg_only(iter
);
2618 if (trace_flags
& TRACE_ITER_BIN
)
2619 return print_bin_fmt(iter
);
2621 if (trace_flags
& TRACE_ITER_HEX
)
2622 return print_hex_fmt(iter
);
2624 if (trace_flags
& TRACE_ITER_RAW
)
2625 return print_raw_fmt(iter
);
2627 return print_trace_fmt(iter
);
2630 void trace_latency_header(struct seq_file
*m
)
2632 struct trace_iterator
*iter
= m
->private;
2634 /* print nothing if the buffers are empty */
2635 if (trace_empty(iter
))
2638 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
)
2639 print_trace_header(m
, iter
);
2641 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2642 print_lat_help_header(m
);
2645 void trace_default_header(struct seq_file
*m
)
2647 struct trace_iterator
*iter
= m
->private;
2649 if (!(trace_flags
& TRACE_ITER_CONTEXT_INFO
))
2652 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
2653 /* print nothing if the buffers are empty */
2654 if (trace_empty(iter
))
2656 print_trace_header(m
, iter
);
2657 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2658 print_lat_help_header(m
);
2660 if (!(trace_flags
& TRACE_ITER_VERBOSE
)) {
2661 if (trace_flags
& TRACE_ITER_IRQ_INFO
)
2662 print_func_help_header_irq(iter
->trace_buffer
, m
);
2664 print_func_help_header(iter
->trace_buffer
, m
);
2669 static void test_ftrace_alive(struct seq_file
*m
)
2671 if (!ftrace_is_dead())
2673 seq_printf(m
, "# WARNING: FUNCTION TRACING IS CORRUPTED\n");
2674 seq_printf(m
, "# MAY BE MISSING FUNCTION EVENTS\n");
2677 #ifdef CONFIG_TRACER_MAX_TRACE
2678 static void show_snapshot_main_help(struct seq_file
*m
)
2680 seq_printf(m
, "# echo 0 > snapshot : Clears and frees snapshot buffer\n");
2681 seq_printf(m
, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
2682 seq_printf(m
, "# Takes a snapshot of the main buffer.\n");
2683 seq_printf(m
, "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate)\n");
2684 seq_printf(m
, "# (Doesn't have to be '2' works with any number that\n");
2685 seq_printf(m
, "# is not a '0' or '1')\n");
2688 static void show_snapshot_percpu_help(struct seq_file
*m
)
2690 seq_printf(m
, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
2691 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
2692 seq_printf(m
, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
2693 seq_printf(m
, "# Takes a snapshot of the main buffer for this cpu.\n");
2695 seq_printf(m
, "# echo 1 > snapshot : Not supported with this kernel.\n");
2696 seq_printf(m
, "# Must use main snapshot file to allocate.\n");
2698 seq_printf(m
, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n");
2699 seq_printf(m
, "# (Doesn't have to be '2' works with any number that\n");
2700 seq_printf(m
, "# is not a '0' or '1')\n");
2703 static void print_snapshot_help(struct seq_file
*m
, struct trace_iterator
*iter
)
2705 if (iter
->tr
->allocated_snapshot
)
2706 seq_printf(m
, "#\n# * Snapshot is allocated *\n#\n");
2708 seq_printf(m
, "#\n# * Snapshot is freed *\n#\n");
2710 seq_printf(m
, "# Snapshot commands:\n");
2711 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
)
2712 show_snapshot_main_help(m
);
2714 show_snapshot_percpu_help(m
);
2717 /* Should never be called */
2718 static inline void print_snapshot_help(struct seq_file
*m
, struct trace_iterator
*iter
) { }
2721 static int s_show(struct seq_file
*m
, void *v
)
2723 struct trace_iterator
*iter
= v
;
2726 if (iter
->ent
== NULL
) {
2728 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
2730 test_ftrace_alive(m
);
2732 if (iter
->snapshot
&& trace_empty(iter
))
2733 print_snapshot_help(m
, iter
);
2734 else if (iter
->trace
&& iter
->trace
->print_header
)
2735 iter
->trace
->print_header(m
);
2737 trace_default_header(m
);
2739 } else if (iter
->leftover
) {
2741 * If we filled the seq_file buffer earlier, we
2742 * want to just show it now.
2744 ret
= trace_print_seq(m
, &iter
->seq
);
2746 /* ret should this time be zero, but you never know */
2747 iter
->leftover
= ret
;
2750 print_trace_line(iter
);
2751 ret
= trace_print_seq(m
, &iter
->seq
);
2753 * If we overflow the seq_file buffer, then it will
2754 * ask us for this data again at start up.
2756 * ret is 0 if seq_file write succeeded.
2759 iter
->leftover
= ret
;
2765 static const struct seq_operations tracer_seq_ops
= {
2772 static struct trace_iterator
*
2773 __tracing_open(struct inode
*inode
, struct file
*file
, bool snapshot
)
2775 struct trace_cpu
*tc
= inode
->i_private
;
2776 struct trace_array
*tr
= tc
->tr
;
2777 struct trace_iterator
*iter
;
2780 if (tracing_disabled
)
2781 return ERR_PTR(-ENODEV
);
2783 iter
= __seq_open_private(file
, &tracer_seq_ops
, sizeof(*iter
));
2785 return ERR_PTR(-ENOMEM
);
2787 iter
->buffer_iter
= kzalloc(sizeof(*iter
->buffer_iter
) * num_possible_cpus(),
2789 if (!iter
->buffer_iter
)
2793 * We make a copy of the current tracer to avoid concurrent
2794 * changes on it while we are reading.
2796 mutex_lock(&trace_types_lock
);
2797 iter
->trace
= kzalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
2801 *iter
->trace
= *tr
->current_trace
;
2803 if (!zalloc_cpumask_var(&iter
->started
, GFP_KERNEL
))
2808 #ifdef CONFIG_TRACER_MAX_TRACE
2809 /* Currently only the top directory has a snapshot */
2810 if (tr
->current_trace
->print_max
|| snapshot
)
2811 iter
->trace_buffer
= &tr
->max_buffer
;
2814 iter
->trace_buffer
= &tr
->trace_buffer
;
2815 iter
->snapshot
= snapshot
;
2817 mutex_init(&iter
->mutex
);
2818 iter
->cpu_file
= tc
->cpu
;
2820 /* Notify the tracer early; before we stop tracing. */
2821 if (iter
->trace
&& iter
->trace
->open
)
2822 iter
->trace
->open(iter
);
2824 /* Annotate start of buffers if we had overruns */
2825 if (ring_buffer_overruns(iter
->trace_buffer
->buffer
))
2826 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
2828 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
2829 if (trace_clocks
[trace_clock_id
].in_ns
)
2830 iter
->iter_flags
|= TRACE_FILE_TIME_IN_NS
;
2832 /* stop the trace while dumping if we are not opening "snapshot" */
2833 if (!iter
->snapshot
)
2834 tracing_stop_tr(tr
);
2836 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
) {
2837 for_each_tracing_cpu(cpu
) {
2838 iter
->buffer_iter
[cpu
] =
2839 ring_buffer_read_prepare(iter
->trace_buffer
->buffer
, cpu
);
2841 ring_buffer_read_prepare_sync();
2842 for_each_tracing_cpu(cpu
) {
2843 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2844 tracing_iter_reset(iter
, cpu
);
2847 cpu
= iter
->cpu_file
;
2848 iter
->buffer_iter
[cpu
] =
2849 ring_buffer_read_prepare(iter
->trace_buffer
->buffer
, cpu
);
2850 ring_buffer_read_prepare_sync();
2851 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2852 tracing_iter_reset(iter
, cpu
);
2857 mutex_unlock(&trace_types_lock
);
2862 mutex_unlock(&trace_types_lock
);
2864 kfree(iter
->buffer_iter
);
2866 seq_release_private(inode
, file
);
2867 return ERR_PTR(-ENOMEM
);
2870 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
2872 if (tracing_disabled
)
2875 filp
->private_data
= inode
->i_private
;
2879 static int tracing_release(struct inode
*inode
, struct file
*file
)
2881 struct seq_file
*m
= file
->private_data
;
2882 struct trace_iterator
*iter
;
2883 struct trace_array
*tr
;
2886 if (!(file
->f_mode
& FMODE_READ
))
2892 mutex_lock(&trace_types_lock
);
2897 for_each_tracing_cpu(cpu
) {
2898 if (iter
->buffer_iter
[cpu
])
2899 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
2902 if (iter
->trace
&& iter
->trace
->close
)
2903 iter
->trace
->close(iter
);
2905 if (!iter
->snapshot
)
2906 /* reenable tracing if it was previously enabled */
2907 tracing_start_tr(tr
);
2908 mutex_unlock(&trace_types_lock
);
2910 mutex_destroy(&iter
->mutex
);
2911 free_cpumask_var(iter
->started
);
2913 kfree(iter
->buffer_iter
);
2914 seq_release_private(inode
, file
);
2918 static int tracing_open(struct inode
*inode
, struct file
*file
)
2920 struct trace_iterator
*iter
;
2923 /* If this file was open for write, then erase contents */
2924 if ((file
->f_mode
& FMODE_WRITE
) &&
2925 (file
->f_flags
& O_TRUNC
)) {
2926 struct trace_cpu
*tc
= inode
->i_private
;
2927 struct trace_array
*tr
= tc
->tr
;
2929 if (tc
->cpu
== RING_BUFFER_ALL_CPUS
)
2930 tracing_reset_online_cpus(&tr
->trace_buffer
);
2932 tracing_reset(&tr
->trace_buffer
, tc
->cpu
);
2935 if (file
->f_mode
& FMODE_READ
) {
2936 iter
= __tracing_open(inode
, file
, false);
2938 ret
= PTR_ERR(iter
);
2939 else if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
2940 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
2946 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
2948 struct tracer
*t
= v
;
2958 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
2963 mutex_lock(&trace_types_lock
);
2964 for (t
= trace_types
; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
2970 static void t_stop(struct seq_file
*m
, void *p
)
2972 mutex_unlock(&trace_types_lock
);
2975 static int t_show(struct seq_file
*m
, void *v
)
2977 struct tracer
*t
= v
;
2982 seq_printf(m
, "%s", t
->name
);
2991 static const struct seq_operations show_traces_seq_ops
= {
2998 static int show_traces_open(struct inode
*inode
, struct file
*file
)
3000 if (tracing_disabled
)
3003 return seq_open(file
, &show_traces_seq_ops
);
3007 tracing_write_stub(struct file
*filp
, const char __user
*ubuf
,
3008 size_t count
, loff_t
*ppos
)
3013 static loff_t
tracing_seek(struct file
*file
, loff_t offset
, int origin
)
3015 if (file
->f_mode
& FMODE_READ
)
3016 return seq_lseek(file
, offset
, origin
);
3021 static const struct file_operations tracing_fops
= {
3022 .open
= tracing_open
,
3024 .write
= tracing_write_stub
,
3025 .llseek
= tracing_seek
,
3026 .release
= tracing_release
,
3029 static const struct file_operations show_traces_fops
= {
3030 .open
= show_traces_open
,
3032 .release
= seq_release
,
3033 .llseek
= seq_lseek
,
3037 * Only trace on a CPU if the bitmask is set:
3039 static cpumask_var_t tracing_cpumask
;
3042 * The tracer itself will not take this lock, but still we want
3043 * to provide a consistent cpumask to user-space:
3045 static DEFINE_MUTEX(tracing_cpumask_update_lock
);
3048 * Temporary storage for the character representation of the
3049 * CPU bitmask (and one more byte for the newline):
3051 static char mask_str
[NR_CPUS
+ 1];
3054 tracing_cpumask_read(struct file
*filp
, char __user
*ubuf
,
3055 size_t count
, loff_t
*ppos
)
3059 mutex_lock(&tracing_cpumask_update_lock
);
3061 len
= cpumask_scnprintf(mask_str
, count
, tracing_cpumask
);
3062 if (count
- len
< 2) {
3066 len
+= sprintf(mask_str
+ len
, "\n");
3067 count
= simple_read_from_buffer(ubuf
, count
, ppos
, mask_str
, NR_CPUS
+1);
3070 mutex_unlock(&tracing_cpumask_update_lock
);
3076 tracing_cpumask_write(struct file
*filp
, const char __user
*ubuf
,
3077 size_t count
, loff_t
*ppos
)
3079 struct trace_array
*tr
= filp
->private_data
;
3080 cpumask_var_t tracing_cpumask_new
;
3083 if (!alloc_cpumask_var(&tracing_cpumask_new
, GFP_KERNEL
))
3086 err
= cpumask_parse_user(ubuf
, count
, tracing_cpumask_new
);
3090 mutex_lock(&tracing_cpumask_update_lock
);
3092 local_irq_disable();
3093 arch_spin_lock(&ftrace_max_lock
);
3094 for_each_tracing_cpu(cpu
) {
3096 * Increase/decrease the disabled counter if we are
3097 * about to flip a bit in the cpumask:
3099 if (cpumask_test_cpu(cpu
, tracing_cpumask
) &&
3100 !cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
3101 atomic_inc(&per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->disabled
);
3102 ring_buffer_record_disable_cpu(tr
->trace_buffer
.buffer
, cpu
);
3104 if (!cpumask_test_cpu(cpu
, tracing_cpumask
) &&
3105 cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
3106 atomic_dec(&per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->disabled
);
3107 ring_buffer_record_enable_cpu(tr
->trace_buffer
.buffer
, cpu
);
3110 arch_spin_unlock(&ftrace_max_lock
);
3113 cpumask_copy(tracing_cpumask
, tracing_cpumask_new
);
3115 mutex_unlock(&tracing_cpumask_update_lock
);
3116 free_cpumask_var(tracing_cpumask_new
);
3121 free_cpumask_var(tracing_cpumask_new
);
3126 static const struct file_operations tracing_cpumask_fops
= {
3127 .open
= tracing_open_generic
,
3128 .read
= tracing_cpumask_read
,
3129 .write
= tracing_cpumask_write
,
3130 .llseek
= generic_file_llseek
,
3133 static int tracing_trace_options_show(struct seq_file
*m
, void *v
)
3135 struct tracer_opt
*trace_opts
;
3136 struct trace_array
*tr
= m
->private;
3140 mutex_lock(&trace_types_lock
);
3141 tracer_flags
= tr
->current_trace
->flags
->val
;
3142 trace_opts
= tr
->current_trace
->flags
->opts
;
3144 for (i
= 0; trace_options
[i
]; i
++) {
3145 if (trace_flags
& (1 << i
))
3146 seq_printf(m
, "%s\n", trace_options
[i
]);
3148 seq_printf(m
, "no%s\n", trace_options
[i
]);
3151 for (i
= 0; trace_opts
[i
].name
; i
++) {
3152 if (tracer_flags
& trace_opts
[i
].bit
)
3153 seq_printf(m
, "%s\n", trace_opts
[i
].name
);
3155 seq_printf(m
, "no%s\n", trace_opts
[i
].name
);
3157 mutex_unlock(&trace_types_lock
);
3162 static int __set_tracer_option(struct tracer
*trace
,
3163 struct tracer_flags
*tracer_flags
,
3164 struct tracer_opt
*opts
, int neg
)
3168 ret
= trace
->set_flag(tracer_flags
->val
, opts
->bit
, !neg
);
3173 tracer_flags
->val
&= ~opts
->bit
;
3175 tracer_flags
->val
|= opts
->bit
;
3179 /* Try to assign a tracer specific option */
3180 static int set_tracer_option(struct tracer
*trace
, char *cmp
, int neg
)
3182 struct tracer_flags
*tracer_flags
= trace
->flags
;
3183 struct tracer_opt
*opts
= NULL
;
3186 for (i
= 0; tracer_flags
->opts
[i
].name
; i
++) {
3187 opts
= &tracer_flags
->opts
[i
];
3189 if (strcmp(cmp
, opts
->name
) == 0)
3190 return __set_tracer_option(trace
, trace
->flags
,
3197 /* Some tracers require overwrite to stay enabled */
3198 int trace_keep_overwrite(struct tracer
*tracer
, u32 mask
, int set
)
3200 if (tracer
->enabled
&& (mask
& TRACE_ITER_OVERWRITE
) && !set
)
3206 int set_tracer_flag(struct trace_array
*tr
, unsigned int mask
, int enabled
)
3208 /* do nothing if flag is already set */
3209 if (!!(trace_flags
& mask
) == !!enabled
)
3212 /* Give the tracer a chance to approve the change */
3213 if (tr
->current_trace
->flag_changed
)
3214 if (tr
->current_trace
->flag_changed(tr
->current_trace
, mask
, !!enabled
))
3218 trace_flags
|= mask
;
3220 trace_flags
&= ~mask
;
3222 if (mask
== TRACE_ITER_RECORD_CMD
)
3223 trace_event_enable_cmd_record(enabled
);
3225 if (mask
== TRACE_ITER_OVERWRITE
) {
3226 ring_buffer_change_overwrite(tr
->trace_buffer
.buffer
, enabled
);
3227 #ifdef CONFIG_TRACER_MAX_TRACE
3228 ring_buffer_change_overwrite(tr
->max_buffer
.buffer
, enabled
);
3232 if (mask
== TRACE_ITER_PRINTK
)
3233 trace_printk_start_stop_comm(enabled
);
3238 static int trace_set_options(struct trace_array
*tr
, char *option
)
3245 cmp
= strstrip(option
);
3247 if (strncmp(cmp
, "no", 2) == 0) {
3252 mutex_lock(&trace_types_lock
);
3254 for (i
= 0; trace_options
[i
]; i
++) {
3255 if (strcmp(cmp
, trace_options
[i
]) == 0) {
3256 ret
= set_tracer_flag(tr
, 1 << i
, !neg
);
3261 /* If no option could be set, test the specific tracer options */
3262 if (!trace_options
[i
])
3263 ret
= set_tracer_option(tr
->current_trace
, cmp
, neg
);
3265 mutex_unlock(&trace_types_lock
);
3271 tracing_trace_options_write(struct file
*filp
, const char __user
*ubuf
,
3272 size_t cnt
, loff_t
*ppos
)
3274 struct seq_file
*m
= filp
->private_data
;
3275 struct trace_array
*tr
= m
->private;
3279 if (cnt
>= sizeof(buf
))
3282 if (copy_from_user(&buf
, ubuf
, cnt
))
3287 ret
= trace_set_options(tr
, buf
);
3296 static int tracing_trace_options_open(struct inode
*inode
, struct file
*file
)
3298 if (tracing_disabled
)
3301 return single_open(file
, tracing_trace_options_show
, inode
->i_private
);
3304 static const struct file_operations tracing_iter_fops
= {
3305 .open
= tracing_trace_options_open
,
3307 .llseek
= seq_lseek
,
3308 .release
= single_release
,
3309 .write
= tracing_trace_options_write
,
3312 static const char readme_msg
[] =
3313 "tracing mini-HOWTO:\n\n"
3314 "# echo 0 > tracing_on : quick way to disable tracing\n"
3315 "# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
3316 " Important files:\n"
3317 " trace\t\t\t- The static contents of the buffer\n"
3318 "\t\t\t To clear the buffer write into this file: echo > trace\n"
3319 " trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
3320 " current_tracer\t- function and latency tracers\n"
3321 " available_tracers\t- list of configured tracers for current_tracer\n"
3322 " buffer_size_kb\t- view and modify size of per cpu buffer\n"
3323 " buffer_total_size_kb - view total size of all cpu buffers\n\n"
3324 " trace_clock\t\t-change the clock used to order events\n"
3325 " local: Per cpu clock but may not be synced across CPUs\n"
3326 " global: Synced across CPUs but slows tracing down.\n"
3327 " counter: Not a clock, but just an increment\n"
3328 " uptime: Jiffy counter from time of boot\n"
3329 " perf: Same clock that perf events use\n"
3330 #ifdef CONFIG_X86_64
3331 " x86-tsc: TSC cycle counter\n"
3333 "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
3334 " tracing_cpumask\t- Limit which CPUs to trace\n"
3335 " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
3336 "\t\t\t Remove sub-buffer with rmdir\n"
3337 " trace_options\t\t- Set format or modify how tracing happens\n"
3338 "\t\t\t Disable an option by adding a suffix 'no' to the option name\n"
3339 #ifdef CONFIG_DYNAMIC_FTRACE
3340 "\n available_filter_functions - list of functions that can be filtered on\n"
3341 " set_ftrace_filter\t- echo function name in here to only trace these functions\n"
3342 " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3343 " modules: Can select a group via module\n"
3344 " Format: :mod:<module-name>\n"
3345 " example: echo :mod:ext3 > set_ftrace_filter\n"
3346 " triggers: a command to perform when function is hit\n"
3347 " Format: <function>:<trigger>[:count]\n"
3348 " trigger: traceon, traceoff\n"
3349 " enable_event:<system>:<event>\n"
3350 " disable_event:<system>:<event>\n"
3351 #ifdef CONFIG_STACKTRACE
3354 #ifdef CONFIG_TRACER_SNAPSHOT
3357 " example: echo do_fault:traceoff > set_ftrace_filter\n"
3358 " echo do_trap:traceoff:3 > set_ftrace_filter\n"
3359 " The first one will disable tracing every time do_fault is hit\n"
3360 " The second will disable tracing at most 3 times when do_trap is hit\n"
3361 " The first time do trap is hit and it disables tracing, the counter\n"
3362 " will decrement to 2. If tracing is already disabled, the counter\n"
3363 " will not decrement. It only decrements when the trigger did work\n"
3364 " To remove trigger without count:\n"
3365 " echo '!<function>:<trigger> > set_ftrace_filter\n"
3366 " To remove trigger with a count:\n"
3367 " echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
3368 " set_ftrace_notrace\t- echo function name in here to never trace.\n"
3369 " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3370 " modules: Can select a group via module command :mod:\n"
3371 " Does not accept triggers\n"
3372 #endif /* CONFIG_DYNAMIC_FTRACE */
3373 #ifdef CONFIG_FUNCTION_TRACER
3374 " set_ftrace_pid\t- Write pid(s) to only function trace those pids (function)\n"
3376 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3377 " set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
3378 " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
3380 #ifdef CONFIG_TRACER_SNAPSHOT
3381 "\n snapshot\t\t- Like 'trace' but shows the content of the static snapshot buffer\n"
3382 "\t\t\t Read the contents for more information\n"
3384 #ifdef CONFIG_STACKTRACE
3385 " stack_trace\t\t- Shows the max stack trace when active\n"
3386 " stack_max_size\t- Shows current max stack size that was traced\n"
3387 "\t\t\t Write into this file to reset the max size (trigger a new trace)\n"
3388 #ifdef CONFIG_DYNAMIC_FTRACE
3389 " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace traces\n"
3391 #endif /* CONFIG_STACKTRACE */
3395 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
3396 size_t cnt
, loff_t
*ppos
)
3398 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
3399 readme_msg
, strlen(readme_msg
));
3402 static const struct file_operations tracing_readme_fops
= {
3403 .open
= tracing_open_generic
,
3404 .read
= tracing_readme_read
,
3405 .llseek
= generic_file_llseek
,
3409 tracing_saved_cmdlines_read(struct file
*file
, char __user
*ubuf
,
3410 size_t cnt
, loff_t
*ppos
)
3419 file_buf
= kmalloc(SAVED_CMDLINES
*(16+TASK_COMM_LEN
), GFP_KERNEL
);
3423 buf_comm
= kmalloc(TASK_COMM_LEN
, GFP_KERNEL
);
3431 for (i
= 0; i
< SAVED_CMDLINES
; i
++) {
3434 pid
= map_cmdline_to_pid
[i
];
3435 if (pid
== -1 || pid
== NO_CMDLINE_MAP
)
3438 trace_find_cmdline(pid
, buf_comm
);
3439 r
= sprintf(buf
, "%d %s\n", pid
, buf_comm
);
3444 len
= simple_read_from_buffer(ubuf
, cnt
, ppos
,
3453 static const struct file_operations tracing_saved_cmdlines_fops
= {
3454 .open
= tracing_open_generic
,
3455 .read
= tracing_saved_cmdlines_read
,
3456 .llseek
= generic_file_llseek
,
3460 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
3461 size_t cnt
, loff_t
*ppos
)
3463 struct trace_array
*tr
= filp
->private_data
;
3464 char buf
[MAX_TRACER_SIZE
+2];
3467 mutex_lock(&trace_types_lock
);
3468 r
= sprintf(buf
, "%s\n", tr
->current_trace
->name
);
3469 mutex_unlock(&trace_types_lock
);
3471 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3474 int tracer_init(struct tracer
*t
, struct trace_array
*tr
)
3476 tracing_reset_online_cpus(&tr
->trace_buffer
);
3480 static void set_buffer_entries(struct trace_buffer
*buf
, unsigned long val
)
3484 for_each_tracing_cpu(cpu
)
3485 per_cpu_ptr(buf
->data
, cpu
)->entries
= val
;
3488 #ifdef CONFIG_TRACER_MAX_TRACE
3489 /* resize @tr's buffer to the size of @size_tr's entries */
3490 static int resize_buffer_duplicate_size(struct trace_buffer
*trace_buf
,
3491 struct trace_buffer
*size_buf
, int cpu_id
)
3495 if (cpu_id
== RING_BUFFER_ALL_CPUS
) {
3496 for_each_tracing_cpu(cpu
) {
3497 ret
= ring_buffer_resize(trace_buf
->buffer
,
3498 per_cpu_ptr(size_buf
->data
, cpu
)->entries
, cpu
);
3501 per_cpu_ptr(trace_buf
->data
, cpu
)->entries
=
3502 per_cpu_ptr(size_buf
->data
, cpu
)->entries
;
3505 ret
= ring_buffer_resize(trace_buf
->buffer
,
3506 per_cpu_ptr(size_buf
->data
, cpu_id
)->entries
, cpu_id
);
3508 per_cpu_ptr(trace_buf
->data
, cpu_id
)->entries
=
3509 per_cpu_ptr(size_buf
->data
, cpu_id
)->entries
;
3514 #endif /* CONFIG_TRACER_MAX_TRACE */
3516 static int __tracing_resize_ring_buffer(struct trace_array
*tr
,
3517 unsigned long size
, int cpu
)
3522 * If kernel or user changes the size of the ring buffer
3523 * we use the size that was given, and we can forget about
3524 * expanding it later.
3526 ring_buffer_expanded
= true;
3528 /* May be called before buffers are initialized */
3529 if (!tr
->trace_buffer
.buffer
)
3532 ret
= ring_buffer_resize(tr
->trace_buffer
.buffer
, size
, cpu
);
3536 #ifdef CONFIG_TRACER_MAX_TRACE
3537 if (!(tr
->flags
& TRACE_ARRAY_FL_GLOBAL
) ||
3538 !tr
->current_trace
->use_max_tr
)
3541 ret
= ring_buffer_resize(tr
->max_buffer
.buffer
, size
, cpu
);
3543 int r
= resize_buffer_duplicate_size(&tr
->trace_buffer
,
3544 &tr
->trace_buffer
, cpu
);
3547 * AARGH! We are left with different
3548 * size max buffer!!!!
3549 * The max buffer is our "snapshot" buffer.
3550 * When a tracer needs a snapshot (one of the
3551 * latency tracers), it swaps the max buffer
3552 * with the saved snap shot. We succeeded to
3553 * update the size of the main buffer, but failed to
3554 * update the size of the max buffer. But when we tried
3555 * to reset the main buffer to the original size, we
3556 * failed there too. This is very unlikely to
3557 * happen, but if it does, warn and kill all
3561 tracing_disabled
= 1;
3566 if (cpu
== RING_BUFFER_ALL_CPUS
)
3567 set_buffer_entries(&tr
->max_buffer
, size
);
3569 per_cpu_ptr(tr
->max_buffer
.data
, cpu
)->entries
= size
;
3572 #endif /* CONFIG_TRACER_MAX_TRACE */
3574 if (cpu
== RING_BUFFER_ALL_CPUS
)
3575 set_buffer_entries(&tr
->trace_buffer
, size
);
3577 per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
= size
;
3582 static ssize_t
tracing_resize_ring_buffer(struct trace_array
*tr
,
3583 unsigned long size
, int cpu_id
)
3587 mutex_lock(&trace_types_lock
);
3589 if (cpu_id
!= RING_BUFFER_ALL_CPUS
) {
3590 /* make sure, this cpu is enabled in the mask */
3591 if (!cpumask_test_cpu(cpu_id
, tracing_buffer_mask
)) {
3597 ret
= __tracing_resize_ring_buffer(tr
, size
, cpu_id
);
3602 mutex_unlock(&trace_types_lock
);
3609 * tracing_update_buffers - used by tracing facility to expand ring buffers
3611 * To save on memory when the tracing is never used on a system with it
3612 * configured in. The ring buffers are set to a minimum size. But once
3613 * a user starts to use the tracing facility, then they need to grow
3614 * to their default size.
3616 * This function is to be called when a tracer is about to be used.
3618 int tracing_update_buffers(void)
3622 mutex_lock(&trace_types_lock
);
3623 if (!ring_buffer_expanded
)
3624 ret
= __tracing_resize_ring_buffer(&global_trace
, trace_buf_size
,
3625 RING_BUFFER_ALL_CPUS
);
3626 mutex_unlock(&trace_types_lock
);
3631 struct trace_option_dentry
;
3633 static struct trace_option_dentry
*
3634 create_trace_option_files(struct trace_array
*tr
, struct tracer
*tracer
);
3637 destroy_trace_option_files(struct trace_option_dentry
*topts
);
3639 static int tracing_set_tracer(const char *buf
)
3641 static struct trace_option_dentry
*topts
;
3642 struct trace_array
*tr
= &global_trace
;
3644 #ifdef CONFIG_TRACER_MAX_TRACE
3649 mutex_lock(&trace_types_lock
);
3651 if (!ring_buffer_expanded
) {
3652 ret
= __tracing_resize_ring_buffer(tr
, trace_buf_size
,
3653 RING_BUFFER_ALL_CPUS
);
3659 for (t
= trace_types
; t
; t
= t
->next
) {
3660 if (strcmp(t
->name
, buf
) == 0)
3667 if (t
== tr
->current_trace
)
3670 trace_branch_disable();
3672 tr
->current_trace
->enabled
= false;
3674 if (tr
->current_trace
->reset
)
3675 tr
->current_trace
->reset(tr
);
3677 /* Current trace needs to be nop_trace before synchronize_sched */
3678 tr
->current_trace
= &nop_trace
;
3680 #ifdef CONFIG_TRACER_MAX_TRACE
3681 had_max_tr
= tr
->allocated_snapshot
;
3683 if (had_max_tr
&& !t
->use_max_tr
) {
3685 * We need to make sure that the update_max_tr sees that
3686 * current_trace changed to nop_trace to keep it from
3687 * swapping the buffers after we resize it.
3688 * The update_max_tr is called from interrupts disabled
3689 * so a synchronized_sched() is sufficient.
3691 synchronize_sched();
3695 destroy_trace_option_files(topts
);
3697 topts
= create_trace_option_files(tr
, t
);
3699 #ifdef CONFIG_TRACER_MAX_TRACE
3700 if (t
->use_max_tr
&& !had_max_tr
) {
3701 ret
= alloc_snapshot(tr
);
3708 ret
= tracer_init(t
, tr
);
3713 tr
->current_trace
= t
;
3714 tr
->current_trace
->enabled
= true;
3715 trace_branch_enable(tr
);
3717 mutex_unlock(&trace_types_lock
);
3723 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
3724 size_t cnt
, loff_t
*ppos
)
3726 char buf
[MAX_TRACER_SIZE
+1];
3733 if (cnt
> MAX_TRACER_SIZE
)
3734 cnt
= MAX_TRACER_SIZE
;
3736 if (copy_from_user(&buf
, ubuf
, cnt
))
3741 /* strip ending whitespace. */
3742 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
3745 err
= tracing_set_tracer(buf
);
3755 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
3756 size_t cnt
, loff_t
*ppos
)
3758 unsigned long *ptr
= filp
->private_data
;
3762 r
= snprintf(buf
, sizeof(buf
), "%ld\n",
3763 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
3764 if (r
> sizeof(buf
))
3766 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3770 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
3771 size_t cnt
, loff_t
*ppos
)
3773 unsigned long *ptr
= filp
->private_data
;
3777 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
3786 static int tracing_open_pipe(struct inode
*inode
, struct file
*filp
)
3788 struct trace_cpu
*tc
= inode
->i_private
;
3789 struct trace_array
*tr
= tc
->tr
;
3790 struct trace_iterator
*iter
;
3793 if (tracing_disabled
)
3796 mutex_lock(&trace_types_lock
);
3798 /* create a buffer to store the information to pass to userspace */
3799 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
3806 * We make a copy of the current tracer to avoid concurrent
3807 * changes on it while we are reading.
3809 iter
->trace
= kmalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
3814 *iter
->trace
= *tr
->current_trace
;
3816 if (!alloc_cpumask_var(&iter
->started
, GFP_KERNEL
)) {
3821 /* trace pipe does not show start of buffer */
3822 cpumask_setall(iter
->started
);
3824 if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
3825 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
3827 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
3828 if (trace_clocks
[trace_clock_id
].in_ns
)
3829 iter
->iter_flags
|= TRACE_FILE_TIME_IN_NS
;
3831 iter
->cpu_file
= tc
->cpu
;
3833 iter
->trace_buffer
= &tc
->tr
->trace_buffer
;
3834 mutex_init(&iter
->mutex
);
3835 filp
->private_data
= iter
;
3837 if (iter
->trace
->pipe_open
)
3838 iter
->trace
->pipe_open(iter
);
3840 nonseekable_open(inode
, filp
);
3842 mutex_unlock(&trace_types_lock
);
3848 mutex_unlock(&trace_types_lock
);
3852 static int tracing_release_pipe(struct inode
*inode
, struct file
*file
)
3854 struct trace_iterator
*iter
= file
->private_data
;
3856 mutex_lock(&trace_types_lock
);
3858 if (iter
->trace
->pipe_close
)
3859 iter
->trace
->pipe_close(iter
);
3861 mutex_unlock(&trace_types_lock
);
3863 free_cpumask_var(iter
->started
);
3864 mutex_destroy(&iter
->mutex
);
3872 trace_poll(struct trace_iterator
*iter
, struct file
*filp
, poll_table
*poll_table
)
3874 /* Iterators are static, they should be filled or empty */
3875 if (trace_buffer_iter(iter
, iter
->cpu_file
))
3876 return POLLIN
| POLLRDNORM
;
3878 if (trace_flags
& TRACE_ITER_BLOCK
)
3880 * Always select as readable when in blocking mode
3882 return POLLIN
| POLLRDNORM
;
3884 return ring_buffer_poll_wait(iter
->trace_buffer
->buffer
, iter
->cpu_file
,
3889 tracing_poll_pipe(struct file
*filp
, poll_table
*poll_table
)
3891 struct trace_iterator
*iter
= filp
->private_data
;
3893 return trace_poll(iter
, filp
, poll_table
);
3897 * This is a make-shift waitqueue.
3898 * A tracer might use this callback on some rare cases:
3900 * 1) the current tracer might hold the runqueue lock when it wakes up
3901 * a reader, hence a deadlock (sched, function, and function graph tracers)
3902 * 2) the function tracers, trace all functions, we don't want
3903 * the overhead of calling wake_up and friends
3904 * (and tracing them too)
3906 * Anyway, this is really very primitive wakeup.
3908 void poll_wait_pipe(struct trace_iterator
*iter
)
3910 set_current_state(TASK_INTERRUPTIBLE
);
3911 /* sleep for 100 msecs, and try again. */
3912 schedule_timeout(HZ
/ 10);
3915 /* Must be called with trace_types_lock mutex held. */
3916 static int tracing_wait_pipe(struct file
*filp
)
3918 struct trace_iterator
*iter
= filp
->private_data
;
3920 while (trace_empty(iter
)) {
3922 if ((filp
->f_flags
& O_NONBLOCK
)) {
3926 mutex_unlock(&iter
->mutex
);
3928 iter
->trace
->wait_pipe(iter
);
3930 mutex_lock(&iter
->mutex
);
3932 if (signal_pending(current
))
3936 * We block until we read something and tracing is disabled.
3937 * We still block if tracing is disabled, but we have never
3938 * read anything. This allows a user to cat this file, and
3939 * then enable tracing. But after we have read something,
3940 * we give an EOF when tracing is again disabled.
3942 * iter->pos will be 0 if we haven't read anything.
3944 if (!tracing_is_enabled() && iter
->pos
)
3955 tracing_read_pipe(struct file
*filp
, char __user
*ubuf
,
3956 size_t cnt
, loff_t
*ppos
)
3958 struct trace_iterator
*iter
= filp
->private_data
;
3959 struct trace_array
*tr
= iter
->tr
;
3962 /* return any leftover data */
3963 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
3967 trace_seq_init(&iter
->seq
);
3969 /* copy the tracer to avoid using a global lock all around */
3970 mutex_lock(&trace_types_lock
);
3971 if (unlikely(iter
->trace
->name
!= tr
->current_trace
->name
))
3972 *iter
->trace
= *tr
->current_trace
;
3973 mutex_unlock(&trace_types_lock
);
3976 * Avoid more than one consumer on a single file descriptor
3977 * This is just a matter of traces coherency, the ring buffer itself
3980 mutex_lock(&iter
->mutex
);
3981 if (iter
->trace
->read
) {
3982 sret
= iter
->trace
->read(iter
, filp
, ubuf
, cnt
, ppos
);
3988 sret
= tracing_wait_pipe(filp
);
3992 /* stop when tracing is finished */
3993 if (trace_empty(iter
)) {
3998 if (cnt
>= PAGE_SIZE
)
3999 cnt
= PAGE_SIZE
- 1;
4001 /* reset all but tr, trace, and overruns */
4002 memset(&iter
->seq
, 0,
4003 sizeof(struct trace_iterator
) -
4004 offsetof(struct trace_iterator
, seq
));
4007 trace_event_read_lock();
4008 trace_access_lock(iter
->cpu_file
);
4009 while (trace_find_next_entry_inc(iter
) != NULL
) {
4010 enum print_line_t ret
;
4011 int len
= iter
->seq
.len
;
4013 ret
= print_trace_line(iter
);
4014 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
4015 /* don't print partial lines */
4016 iter
->seq
.len
= len
;
4019 if (ret
!= TRACE_TYPE_NO_CONSUME
)
4020 trace_consume(iter
);
4022 if (iter
->seq
.len
>= cnt
)
4026 * Setting the full flag means we reached the trace_seq buffer
4027 * size and we should leave by partial output condition above.
4028 * One of the trace_seq_* functions is not used properly.
4030 WARN_ONCE(iter
->seq
.full
, "full flag set for trace type %d",
4033 trace_access_unlock(iter
->cpu_file
);
4034 trace_event_read_unlock();
4036 /* Now copy what we have to the user */
4037 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
4038 if (iter
->seq
.readpos
>= iter
->seq
.len
)
4039 trace_seq_init(&iter
->seq
);
4042 * If there was nothing to send to user, in spite of consuming trace
4043 * entries, go back to wait for more entries.
4049 mutex_unlock(&iter
->mutex
);
4054 static void tracing_pipe_buf_release(struct pipe_inode_info
*pipe
,
4055 struct pipe_buffer
*buf
)
4057 __free_page(buf
->page
);
4060 static void tracing_spd_release_pipe(struct splice_pipe_desc
*spd
,
4063 __free_page(spd
->pages
[idx
]);
4066 static const struct pipe_buf_operations tracing_pipe_buf_ops
= {
4068 .map
= generic_pipe_buf_map
,
4069 .unmap
= generic_pipe_buf_unmap
,
4070 .confirm
= generic_pipe_buf_confirm
,
4071 .release
= tracing_pipe_buf_release
,
4072 .steal
= generic_pipe_buf_steal
,
4073 .get
= generic_pipe_buf_get
,
4077 tracing_fill_pipe_page(size_t rem
, struct trace_iterator
*iter
)
4082 /* Seq buffer is page-sized, exactly what we need. */
4084 count
= iter
->seq
.len
;
4085 ret
= print_trace_line(iter
);
4086 count
= iter
->seq
.len
- count
;
4089 iter
->seq
.len
-= count
;
4092 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
4093 iter
->seq
.len
-= count
;
4097 if (ret
!= TRACE_TYPE_NO_CONSUME
)
4098 trace_consume(iter
);
4100 if (!trace_find_next_entry_inc(iter
)) {
4110 static ssize_t
tracing_splice_read_pipe(struct file
*filp
,
4112 struct pipe_inode_info
*pipe
,
4116 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
4117 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
4118 struct trace_iterator
*iter
= filp
->private_data
;
4119 struct splice_pipe_desc spd
= {
4121 .partial
= partial_def
,
4122 .nr_pages
= 0, /* This gets updated below. */
4123 .nr_pages_max
= PIPE_DEF_BUFFERS
,
4125 .ops
= &tracing_pipe_buf_ops
,
4126 .spd_release
= tracing_spd_release_pipe
,
4128 struct trace_array
*tr
= iter
->tr
;
4133 if (splice_grow_spd(pipe
, &spd
))
4136 /* copy the tracer to avoid using a global lock all around */
4137 mutex_lock(&trace_types_lock
);
4138 if (unlikely(iter
->trace
->name
!= tr
->current_trace
->name
))
4139 *iter
->trace
= *tr
->current_trace
;
4140 mutex_unlock(&trace_types_lock
);
4142 mutex_lock(&iter
->mutex
);
4144 if (iter
->trace
->splice_read
) {
4145 ret
= iter
->trace
->splice_read(iter
, filp
,
4146 ppos
, pipe
, len
, flags
);
4151 ret
= tracing_wait_pipe(filp
);
4155 if (!iter
->ent
&& !trace_find_next_entry_inc(iter
)) {
4160 trace_event_read_lock();
4161 trace_access_lock(iter
->cpu_file
);
4163 /* Fill as many pages as possible. */
4164 for (i
= 0, rem
= len
; i
< pipe
->buffers
&& rem
; i
++) {
4165 spd
.pages
[i
] = alloc_page(GFP_KERNEL
);
4169 rem
= tracing_fill_pipe_page(rem
, iter
);
4171 /* Copy the data into the page, so we can start over. */
4172 ret
= trace_seq_to_buffer(&iter
->seq
,
4173 page_address(spd
.pages
[i
]),
4176 __free_page(spd
.pages
[i
]);
4179 spd
.partial
[i
].offset
= 0;
4180 spd
.partial
[i
].len
= iter
->seq
.len
;
4182 trace_seq_init(&iter
->seq
);
4185 trace_access_unlock(iter
->cpu_file
);
4186 trace_event_read_unlock();
4187 mutex_unlock(&iter
->mutex
);
4191 ret
= splice_to_pipe(pipe
, &spd
);
4193 splice_shrink_spd(&spd
);
4197 mutex_unlock(&iter
->mutex
);
4202 tracing_entries_read(struct file
*filp
, char __user
*ubuf
,
4203 size_t cnt
, loff_t
*ppos
)
4205 struct trace_cpu
*tc
= filp
->private_data
;
4206 struct trace_array
*tr
= tc
->tr
;
4211 mutex_lock(&trace_types_lock
);
4213 if (tc
->cpu
== RING_BUFFER_ALL_CPUS
) {
4214 int cpu
, buf_size_same
;
4219 /* check if all cpu sizes are same */
4220 for_each_tracing_cpu(cpu
) {
4221 /* fill in the size from first enabled cpu */
4223 size
= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
;
4224 if (size
!= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
) {
4230 if (buf_size_same
) {
4231 if (!ring_buffer_expanded
)
4232 r
= sprintf(buf
, "%lu (expanded: %lu)\n",
4234 trace_buf_size
>> 10);
4236 r
= sprintf(buf
, "%lu\n", size
>> 10);
4238 r
= sprintf(buf
, "X\n");
4240 r
= sprintf(buf
, "%lu\n", per_cpu_ptr(tr
->trace_buffer
.data
, tc
->cpu
)->entries
>> 10);
4242 mutex_unlock(&trace_types_lock
);
4244 ret
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
4249 tracing_entries_write(struct file
*filp
, const char __user
*ubuf
,
4250 size_t cnt
, loff_t
*ppos
)
4252 struct trace_cpu
*tc
= filp
->private_data
;
4256 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
4260 /* must have at least 1 entry */
4264 /* value is in KB */
4267 ret
= tracing_resize_ring_buffer(tc
->tr
, val
, tc
->cpu
);
4277 tracing_total_entries_read(struct file
*filp
, char __user
*ubuf
,
4278 size_t cnt
, loff_t
*ppos
)
4280 struct trace_array
*tr
= filp
->private_data
;
4283 unsigned long size
= 0, expanded_size
= 0;
4285 mutex_lock(&trace_types_lock
);
4286 for_each_tracing_cpu(cpu
) {
4287 size
+= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
>> 10;
4288 if (!ring_buffer_expanded
)
4289 expanded_size
+= trace_buf_size
>> 10;
4291 if (ring_buffer_expanded
)
4292 r
= sprintf(buf
, "%lu\n", size
);
4294 r
= sprintf(buf
, "%lu (expanded: %lu)\n", size
, expanded_size
);
4295 mutex_unlock(&trace_types_lock
);
4297 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
4301 tracing_free_buffer_write(struct file
*filp
, const char __user
*ubuf
,
4302 size_t cnt
, loff_t
*ppos
)
4305 * There is no need to read what the user has written, this function
4306 * is just to make sure that there is no error when "echo" is used
4315 tracing_free_buffer_release(struct inode
*inode
, struct file
*filp
)
4317 struct trace_array
*tr
= inode
->i_private
;
4319 /* disable tracing ? */
4320 if (trace_flags
& TRACE_ITER_STOP_ON_FREE
)
4322 /* resize the ring buffer to 0 */
4323 tracing_resize_ring_buffer(tr
, 0, RING_BUFFER_ALL_CPUS
);
4329 tracing_mark_write(struct file
*filp
, const char __user
*ubuf
,
4330 size_t cnt
, loff_t
*fpos
)
4332 unsigned long addr
= (unsigned long)ubuf
;
4333 struct ring_buffer_event
*event
;
4334 struct ring_buffer
*buffer
;
4335 struct print_entry
*entry
;
4336 unsigned long irq_flags
;
4337 struct page
*pages
[2];
4347 if (tracing_disabled
)
4350 if (!(trace_flags
& TRACE_ITER_MARKERS
))
4353 if (cnt
> TRACE_BUF_SIZE
)
4354 cnt
= TRACE_BUF_SIZE
;
4357 * Userspace is injecting traces into the kernel trace buffer.
4358 * We want to be as non intrusive as possible.
4359 * To do so, we do not want to allocate any special buffers
4360 * or take any locks, but instead write the userspace data
4361 * straight into the ring buffer.
4363 * First we need to pin the userspace buffer into memory,
4364 * which, most likely it is, because it just referenced it.
4365 * But there's no guarantee that it is. By using get_user_pages_fast()
4366 * and kmap_atomic/kunmap_atomic() we can get access to the
4367 * pages directly. We then write the data directly into the
4370 BUILD_BUG_ON(TRACE_BUF_SIZE
>= PAGE_SIZE
);
4372 /* check if we cross pages */
4373 if ((addr
& PAGE_MASK
) != ((addr
+ cnt
) & PAGE_MASK
))
4376 offset
= addr
& (PAGE_SIZE
- 1);
4379 ret
= get_user_pages_fast(addr
, nr_pages
, 0, pages
);
4380 if (ret
< nr_pages
) {
4382 put_page(pages
[ret
]);
4387 for (i
= 0; i
< nr_pages
; i
++)
4388 map_page
[i
] = kmap_atomic(pages
[i
]);
4390 local_save_flags(irq_flags
);
4391 size
= sizeof(*entry
) + cnt
+ 2; /* possible \n added */
4392 buffer
= global_trace
.trace_buffer
.buffer
;
4393 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, size
,
4394 irq_flags
, preempt_count());
4396 /* Ring buffer disabled, return as if not open for write */
4401 entry
= ring_buffer_event_data(event
);
4402 entry
->ip
= _THIS_IP_
;
4404 if (nr_pages
== 2) {
4405 len
= PAGE_SIZE
- offset
;
4406 memcpy(&entry
->buf
, map_page
[0] + offset
, len
);
4407 memcpy(&entry
->buf
[len
], map_page
[1], cnt
- len
);
4409 memcpy(&entry
->buf
, map_page
[0] + offset
, cnt
);
4411 if (entry
->buf
[cnt
- 1] != '\n') {
4412 entry
->buf
[cnt
] = '\n';
4413 entry
->buf
[cnt
+ 1] = '\0';
4415 entry
->buf
[cnt
] = '\0';
4417 __buffer_unlock_commit(buffer
, event
);
4424 for (i
= 0; i
< nr_pages
; i
++){
4425 kunmap_atomic(map_page
[i
]);
4432 static int tracing_clock_show(struct seq_file
*m
, void *v
)
4434 struct trace_array
*tr
= m
->private;
4437 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++)
4439 "%s%s%s%s", i
? " " : "",
4440 i
== tr
->clock_id
? "[" : "", trace_clocks
[i
].name
,
4441 i
== tr
->clock_id
? "]" : "");
4447 static ssize_t
tracing_clock_write(struct file
*filp
, const char __user
*ubuf
,
4448 size_t cnt
, loff_t
*fpos
)
4450 struct seq_file
*m
= filp
->private_data
;
4451 struct trace_array
*tr
= m
->private;
4453 const char *clockstr
;
4456 if (cnt
>= sizeof(buf
))
4459 if (copy_from_user(&buf
, ubuf
, cnt
))
4464 clockstr
= strstrip(buf
);
4466 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++) {
4467 if (strcmp(trace_clocks
[i
].name
, clockstr
) == 0)
4470 if (i
== ARRAY_SIZE(trace_clocks
))
4473 mutex_lock(&trace_types_lock
);
4477 ring_buffer_set_clock(tr
->trace_buffer
.buffer
, trace_clocks
[i
].func
);
4480 * New clock may not be consistent with the previous clock.
4481 * Reset the buffer so that it doesn't have incomparable timestamps.
4483 tracing_reset_online_cpus(&global_trace
.trace_buffer
);
4485 #ifdef CONFIG_TRACER_MAX_TRACE
4486 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
&& tr
->max_buffer
.buffer
)
4487 ring_buffer_set_clock(tr
->max_buffer
.buffer
, trace_clocks
[i
].func
);
4488 tracing_reset_online_cpus(&global_trace
.max_buffer
);
4491 mutex_unlock(&trace_types_lock
);
4498 static int tracing_clock_open(struct inode
*inode
, struct file
*file
)
4500 if (tracing_disabled
)
4503 return single_open(file
, tracing_clock_show
, inode
->i_private
);
4506 struct ftrace_buffer_info
{
4507 struct trace_iterator iter
;
4512 #ifdef CONFIG_TRACER_SNAPSHOT
4513 static int tracing_snapshot_open(struct inode
*inode
, struct file
*file
)
4515 struct trace_cpu
*tc
= inode
->i_private
;
4516 struct trace_iterator
*iter
;
4520 if (file
->f_mode
& FMODE_READ
) {
4521 iter
= __tracing_open(inode
, file
, true);
4523 ret
= PTR_ERR(iter
);
4525 /* Writes still need the seq_file to hold the private data */
4526 m
= kzalloc(sizeof(*m
), GFP_KERNEL
);
4529 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
4535 iter
->trace_buffer
= &tc
->tr
->max_buffer
;
4536 iter
->cpu_file
= tc
->cpu
;
4538 file
->private_data
= m
;
4545 tracing_snapshot_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
4548 struct seq_file
*m
= filp
->private_data
;
4549 struct trace_iterator
*iter
= m
->private;
4550 struct trace_array
*tr
= iter
->tr
;
4554 ret
= tracing_update_buffers();
4558 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
4562 mutex_lock(&trace_types_lock
);
4564 if (tr
->current_trace
->use_max_tr
) {
4571 if (iter
->cpu_file
!= RING_BUFFER_ALL_CPUS
) {
4575 if (tr
->allocated_snapshot
)
4579 /* Only allow per-cpu swap if the ring buffer supports it */
4580 #ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
4581 if (iter
->cpu_file
!= RING_BUFFER_ALL_CPUS
) {
4586 if (!tr
->allocated_snapshot
) {
4587 ret
= alloc_snapshot(tr
);
4591 local_irq_disable();
4592 /* Now, we're going to swap */
4593 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
)
4594 update_max_tr(tr
, current
, smp_processor_id());
4596 update_max_tr_single(tr
, current
, iter
->cpu_file
);
4600 if (tr
->allocated_snapshot
) {
4601 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
)
4602 tracing_reset_online_cpus(&tr
->max_buffer
);
4604 tracing_reset(&tr
->max_buffer
, iter
->cpu_file
);
4614 mutex_unlock(&trace_types_lock
);
4618 static int tracing_snapshot_release(struct inode
*inode
, struct file
*file
)
4620 struct seq_file
*m
= file
->private_data
;
4622 if (file
->f_mode
& FMODE_READ
)
4623 return tracing_release(inode
, file
);
4625 /* If write only, the seq_file is just a stub */
4633 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
);
4634 static ssize_t
tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
4635 size_t count
, loff_t
*ppos
);
4636 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
);
4637 static ssize_t
tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
4638 struct pipe_inode_info
*pipe
, size_t len
, unsigned int flags
);
4640 static int snapshot_raw_open(struct inode
*inode
, struct file
*filp
)
4642 struct ftrace_buffer_info
*info
;
4645 ret
= tracing_buffers_open(inode
, filp
);
4649 info
= filp
->private_data
;
4651 if (info
->iter
.trace
->use_max_tr
) {
4652 tracing_buffers_release(inode
, filp
);
4656 info
->iter
.snapshot
= true;
4657 info
->iter
.trace_buffer
= &info
->iter
.tr
->max_buffer
;
4662 #endif /* CONFIG_TRACER_SNAPSHOT */
4665 static const struct file_operations tracing_max_lat_fops
= {
4666 .open
= tracing_open_generic
,
4667 .read
= tracing_max_lat_read
,
4668 .write
= tracing_max_lat_write
,
4669 .llseek
= generic_file_llseek
,
4672 static const struct file_operations set_tracer_fops
= {
4673 .open
= tracing_open_generic
,
4674 .read
= tracing_set_trace_read
,
4675 .write
= tracing_set_trace_write
,
4676 .llseek
= generic_file_llseek
,
4679 static const struct file_operations tracing_pipe_fops
= {
4680 .open
= tracing_open_pipe
,
4681 .poll
= tracing_poll_pipe
,
4682 .read
= tracing_read_pipe
,
4683 .splice_read
= tracing_splice_read_pipe
,
4684 .release
= tracing_release_pipe
,
4685 .llseek
= no_llseek
,
4688 static const struct file_operations tracing_entries_fops
= {
4689 .open
= tracing_open_generic
,
4690 .read
= tracing_entries_read
,
4691 .write
= tracing_entries_write
,
4692 .llseek
= generic_file_llseek
,
4695 static const struct file_operations tracing_total_entries_fops
= {
4696 .open
= tracing_open_generic
,
4697 .read
= tracing_total_entries_read
,
4698 .llseek
= generic_file_llseek
,
4701 static const struct file_operations tracing_free_buffer_fops
= {
4702 .write
= tracing_free_buffer_write
,
4703 .release
= tracing_free_buffer_release
,
4706 static const struct file_operations tracing_mark_fops
= {
4707 .open
= tracing_open_generic
,
4708 .write
= tracing_mark_write
,
4709 .llseek
= generic_file_llseek
,
4712 static const struct file_operations trace_clock_fops
= {
4713 .open
= tracing_clock_open
,
4715 .llseek
= seq_lseek
,
4716 .release
= single_release
,
4717 .write
= tracing_clock_write
,
4720 #ifdef CONFIG_TRACER_SNAPSHOT
4721 static const struct file_operations snapshot_fops
= {
4722 .open
= tracing_snapshot_open
,
4724 .write
= tracing_snapshot_write
,
4725 .llseek
= tracing_seek
,
4726 .release
= tracing_snapshot_release
,
4729 static const struct file_operations snapshot_raw_fops
= {
4730 .open
= snapshot_raw_open
,
4731 .read
= tracing_buffers_read
,
4732 .release
= tracing_buffers_release
,
4733 .splice_read
= tracing_buffers_splice_read
,
4734 .llseek
= no_llseek
,
4737 #endif /* CONFIG_TRACER_SNAPSHOT */
4739 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
)
4741 struct trace_cpu
*tc
= inode
->i_private
;
4742 struct trace_array
*tr
= tc
->tr
;
4743 struct ftrace_buffer_info
*info
;
4745 if (tracing_disabled
)
4748 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
4752 mutex_lock(&trace_types_lock
);
4757 info
->iter
.cpu_file
= tc
->cpu
;
4758 info
->iter
.trace
= tr
->current_trace
;
4759 info
->iter
.trace_buffer
= &tr
->trace_buffer
;
4761 /* Force reading ring buffer for first read */
4762 info
->read
= (unsigned int)-1;
4764 filp
->private_data
= info
;
4766 mutex_unlock(&trace_types_lock
);
4768 return nonseekable_open(inode
, filp
);
4772 tracing_buffers_poll(struct file
*filp
, poll_table
*poll_table
)
4774 struct ftrace_buffer_info
*info
= filp
->private_data
;
4775 struct trace_iterator
*iter
= &info
->iter
;
4777 return trace_poll(iter
, filp
, poll_table
);
4781 tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
4782 size_t count
, loff_t
*ppos
)
4784 struct ftrace_buffer_info
*info
= filp
->private_data
;
4785 struct trace_iterator
*iter
= &info
->iter
;
4792 mutex_lock(&trace_types_lock
);
4794 #ifdef CONFIG_TRACER_MAX_TRACE
4795 if (iter
->snapshot
&& iter
->tr
->current_trace
->use_max_tr
) {
4802 info
->spare
= ring_buffer_alloc_read_page(iter
->trace_buffer
->buffer
,
4808 /* Do we have previous read data to read? */
4809 if (info
->read
< PAGE_SIZE
)
4813 trace_access_lock(iter
->cpu_file
);
4814 ret
= ring_buffer_read_page(iter
->trace_buffer
->buffer
,
4818 trace_access_unlock(iter
->cpu_file
);
4821 if (trace_empty(iter
)) {
4822 if ((filp
->f_flags
& O_NONBLOCK
)) {
4826 mutex_unlock(&trace_types_lock
);
4827 iter
->trace
->wait_pipe(iter
);
4828 mutex_lock(&trace_types_lock
);
4829 if (signal_pending(current
)) {
4841 size
= PAGE_SIZE
- info
->read
;
4845 ret
= copy_to_user(ubuf
, info
->spare
+ info
->read
, size
);
4856 mutex_unlock(&trace_types_lock
);
4861 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
)
4863 struct ftrace_buffer_info
*info
= file
->private_data
;
4864 struct trace_iterator
*iter
= &info
->iter
;
4866 mutex_lock(&trace_types_lock
);
4868 WARN_ON(!iter
->tr
->ref
);
4872 ring_buffer_free_read_page(iter
->trace_buffer
->buffer
, info
->spare
);
4875 mutex_unlock(&trace_types_lock
);
4881 struct ring_buffer
*buffer
;
4886 static void buffer_pipe_buf_release(struct pipe_inode_info
*pipe
,
4887 struct pipe_buffer
*buf
)
4889 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
4894 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
4899 static void buffer_pipe_buf_get(struct pipe_inode_info
*pipe
,
4900 struct pipe_buffer
*buf
)
4902 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
4907 /* Pipe buffer operations for a buffer. */
4908 static const struct pipe_buf_operations buffer_pipe_buf_ops
= {
4910 .map
= generic_pipe_buf_map
,
4911 .unmap
= generic_pipe_buf_unmap
,
4912 .confirm
= generic_pipe_buf_confirm
,
4913 .release
= buffer_pipe_buf_release
,
4914 .steal
= generic_pipe_buf_steal
,
4915 .get
= buffer_pipe_buf_get
,
4919 * Callback from splice_to_pipe(), if we need to release some pages
4920 * at the end of the spd in case we error'ed out in filling the pipe.
4922 static void buffer_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
4924 struct buffer_ref
*ref
=
4925 (struct buffer_ref
*)spd
->partial
[i
].private;
4930 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
4932 spd
->partial
[i
].private = 0;
4936 tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
4937 struct pipe_inode_info
*pipe
, size_t len
,
4940 struct ftrace_buffer_info
*info
= file
->private_data
;
4941 struct trace_iterator
*iter
= &info
->iter
;
4942 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
4943 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
4944 struct splice_pipe_desc spd
= {
4946 .partial
= partial_def
,
4947 .nr_pages_max
= PIPE_DEF_BUFFERS
,
4949 .ops
= &buffer_pipe_buf_ops
,
4950 .spd_release
= buffer_spd_release
,
4952 struct buffer_ref
*ref
;
4953 int entries
, size
, i
;
4956 mutex_lock(&trace_types_lock
);
4958 #ifdef CONFIG_TRACER_MAX_TRACE
4959 if (iter
->snapshot
&& iter
->tr
->current_trace
->use_max_tr
) {
4965 if (splice_grow_spd(pipe
, &spd
)) {
4970 if (*ppos
& (PAGE_SIZE
- 1)) {
4975 if (len
& (PAGE_SIZE
- 1)) {
4976 if (len
< PAGE_SIZE
) {
4984 trace_access_lock(iter
->cpu_file
);
4985 entries
= ring_buffer_entries_cpu(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
4987 for (i
= 0; i
< pipe
->buffers
&& len
&& entries
; i
++, len
-= PAGE_SIZE
) {
4991 ref
= kzalloc(sizeof(*ref
), GFP_KERNEL
);
4996 ref
->buffer
= iter
->trace_buffer
->buffer
;
4997 ref
->page
= ring_buffer_alloc_read_page(ref
->buffer
, iter
->cpu_file
);
5003 r
= ring_buffer_read_page(ref
->buffer
, &ref
->page
,
5004 len
, iter
->cpu_file
, 1);
5006 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
5012 * zero out any left over data, this is going to
5015 size
= ring_buffer_page_len(ref
->page
);
5016 if (size
< PAGE_SIZE
)
5017 memset(ref
->page
+ size
, 0, PAGE_SIZE
- size
);
5019 page
= virt_to_page(ref
->page
);
5021 spd
.pages
[i
] = page
;
5022 spd
.partial
[i
].len
= PAGE_SIZE
;
5023 spd
.partial
[i
].offset
= 0;
5024 spd
.partial
[i
].private = (unsigned long)ref
;
5028 entries
= ring_buffer_entries_cpu(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
5031 trace_access_unlock(iter
->cpu_file
);
5034 /* did we read anything? */
5035 if (!spd
.nr_pages
) {
5036 if ((file
->f_flags
& O_NONBLOCK
) || (flags
& SPLICE_F_NONBLOCK
)) {
5040 mutex_unlock(&trace_types_lock
);
5041 iter
->trace
->wait_pipe(iter
);
5042 mutex_lock(&trace_types_lock
);
5043 if (signal_pending(current
)) {
5050 ret
= splice_to_pipe(pipe
, &spd
);
5051 splice_shrink_spd(&spd
);
5053 mutex_unlock(&trace_types_lock
);
5058 static const struct file_operations tracing_buffers_fops
= {
5059 .open
= tracing_buffers_open
,
5060 .read
= tracing_buffers_read
,
5061 .poll
= tracing_buffers_poll
,
5062 .release
= tracing_buffers_release
,
5063 .splice_read
= tracing_buffers_splice_read
,
5064 .llseek
= no_llseek
,
5068 tracing_stats_read(struct file
*filp
, char __user
*ubuf
,
5069 size_t count
, loff_t
*ppos
)
5071 struct trace_cpu
*tc
= filp
->private_data
;
5072 struct trace_array
*tr
= tc
->tr
;
5073 struct trace_buffer
*trace_buf
= &tr
->trace_buffer
;
5074 struct trace_seq
*s
;
5076 unsigned long long t
;
5077 unsigned long usec_rem
;
5080 s
= kmalloc(sizeof(*s
), GFP_KERNEL
);
5086 cnt
= ring_buffer_entries_cpu(trace_buf
->buffer
, cpu
);
5087 trace_seq_printf(s
, "entries: %ld\n", cnt
);
5089 cnt
= ring_buffer_overrun_cpu(trace_buf
->buffer
, cpu
);
5090 trace_seq_printf(s
, "overrun: %ld\n", cnt
);
5092 cnt
= ring_buffer_commit_overrun_cpu(trace_buf
->buffer
, cpu
);
5093 trace_seq_printf(s
, "commit overrun: %ld\n", cnt
);
5095 cnt
= ring_buffer_bytes_cpu(trace_buf
->buffer
, cpu
);
5096 trace_seq_printf(s
, "bytes: %ld\n", cnt
);
5098 if (trace_clocks
[trace_clock_id
].in_ns
) {
5099 /* local or global for trace_clock */
5100 t
= ns2usecs(ring_buffer_oldest_event_ts(trace_buf
->buffer
, cpu
));
5101 usec_rem
= do_div(t
, USEC_PER_SEC
);
5102 trace_seq_printf(s
, "oldest event ts: %5llu.%06lu\n",
5105 t
= ns2usecs(ring_buffer_time_stamp(trace_buf
->buffer
, cpu
));
5106 usec_rem
= do_div(t
, USEC_PER_SEC
);
5107 trace_seq_printf(s
, "now ts: %5llu.%06lu\n", t
, usec_rem
);
5109 /* counter or tsc mode for trace_clock */
5110 trace_seq_printf(s
, "oldest event ts: %llu\n",
5111 ring_buffer_oldest_event_ts(trace_buf
->buffer
, cpu
));
5113 trace_seq_printf(s
, "now ts: %llu\n",
5114 ring_buffer_time_stamp(trace_buf
->buffer
, cpu
));
5117 cnt
= ring_buffer_dropped_events_cpu(trace_buf
->buffer
, cpu
);
5118 trace_seq_printf(s
, "dropped events: %ld\n", cnt
);
5120 cnt
= ring_buffer_read_events_cpu(trace_buf
->buffer
, cpu
);
5121 trace_seq_printf(s
, "read events: %ld\n", cnt
);
5123 count
= simple_read_from_buffer(ubuf
, count
, ppos
, s
->buffer
, s
->len
);
5130 static const struct file_operations tracing_stats_fops
= {
5131 .open
= tracing_open_generic
,
5132 .read
= tracing_stats_read
,
5133 .llseek
= generic_file_llseek
,
5136 #ifdef CONFIG_DYNAMIC_FTRACE
5138 int __weak
ftrace_arch_read_dyn_info(char *buf
, int size
)
5144 tracing_read_dyn_info(struct file
*filp
, char __user
*ubuf
,
5145 size_t cnt
, loff_t
*ppos
)
5147 static char ftrace_dyn_info_buffer
[1024];
5148 static DEFINE_MUTEX(dyn_info_mutex
);
5149 unsigned long *p
= filp
->private_data
;
5150 char *buf
= ftrace_dyn_info_buffer
;
5151 int size
= ARRAY_SIZE(ftrace_dyn_info_buffer
);
5154 mutex_lock(&dyn_info_mutex
);
5155 r
= sprintf(buf
, "%ld ", *p
);
5157 r
+= ftrace_arch_read_dyn_info(buf
+r
, (size
-1)-r
);
5160 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
5162 mutex_unlock(&dyn_info_mutex
);
5167 static const struct file_operations tracing_dyn_info_fops
= {
5168 .open
= tracing_open_generic
,
5169 .read
= tracing_read_dyn_info
,
5170 .llseek
= generic_file_llseek
,
5172 #endif /* CONFIG_DYNAMIC_FTRACE */
5174 #if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
5176 ftrace_snapshot(unsigned long ip
, unsigned long parent_ip
, void **data
)
5182 ftrace_count_snapshot(unsigned long ip
, unsigned long parent_ip
, void **data
)
5184 unsigned long *count
= (long *)data
;
5196 ftrace_snapshot_print(struct seq_file
*m
, unsigned long ip
,
5197 struct ftrace_probe_ops
*ops
, void *data
)
5199 long count
= (long)data
;
5201 seq_printf(m
, "%ps:", (void *)ip
);
5203 seq_printf(m
, "snapshot");
5206 seq_printf(m
, ":unlimited\n");
5208 seq_printf(m
, ":count=%ld\n", count
);
5213 static struct ftrace_probe_ops snapshot_probe_ops
= {
5214 .func
= ftrace_snapshot
,
5215 .print
= ftrace_snapshot_print
,
5218 static struct ftrace_probe_ops snapshot_count_probe_ops
= {
5219 .func
= ftrace_count_snapshot
,
5220 .print
= ftrace_snapshot_print
,
5224 ftrace_trace_snapshot_callback(struct ftrace_hash
*hash
,
5225 char *glob
, char *cmd
, char *param
, int enable
)
5227 struct ftrace_probe_ops
*ops
;
5228 void *count
= (void *)-1;
5232 /* hash funcs only work with set_ftrace_filter */
5236 ops
= param
? &snapshot_count_probe_ops
: &snapshot_probe_ops
;
5238 if (glob
[0] == '!') {
5239 unregister_ftrace_function_probe_func(glob
+1, ops
);
5246 number
= strsep(¶m
, ":");
5248 if (!strlen(number
))
5252 * We use the callback data field (which is a pointer)
5255 ret
= kstrtoul(number
, 0, (unsigned long *)&count
);
5260 ret
= register_ftrace_function_probe(glob
, ops
, count
);
5263 alloc_snapshot(&global_trace
);
5265 return ret
< 0 ? ret
: 0;
5268 static struct ftrace_func_command ftrace_snapshot_cmd
= {
5270 .func
= ftrace_trace_snapshot_callback
,
5273 static int register_snapshot_cmd(void)
5275 return register_ftrace_command(&ftrace_snapshot_cmd
);
5278 static inline int register_snapshot_cmd(void) { return 0; }
5279 #endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
5281 struct dentry
*tracing_init_dentry_tr(struct trace_array
*tr
)
5286 if (!debugfs_initialized())
5289 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
5290 tr
->dir
= debugfs_create_dir("tracing", NULL
);
5293 pr_warn_once("Could not create debugfs directory 'tracing'\n");
5298 struct dentry
*tracing_init_dentry(void)
5300 return tracing_init_dentry_tr(&global_trace
);
5303 static struct dentry
*tracing_dentry_percpu(struct trace_array
*tr
, int cpu
)
5305 struct dentry
*d_tracer
;
5308 return tr
->percpu_dir
;
5310 d_tracer
= tracing_init_dentry_tr(tr
);
5314 tr
->percpu_dir
= debugfs_create_dir("per_cpu", d_tracer
);
5316 WARN_ONCE(!tr
->percpu_dir
,
5317 "Could not create debugfs directory 'per_cpu/%d'\n", cpu
);
5319 return tr
->percpu_dir
;
5323 tracing_init_debugfs_percpu(struct trace_array
*tr
, long cpu
)
5325 struct trace_array_cpu
*data
= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
);
5326 struct dentry
*d_percpu
= tracing_dentry_percpu(tr
, cpu
);
5327 struct dentry
*d_cpu
;
5328 char cpu_dir
[30]; /* 30 characters should be more than enough */
5333 snprintf(cpu_dir
, 30, "cpu%ld", cpu
);
5334 d_cpu
= debugfs_create_dir(cpu_dir
, d_percpu
);
5336 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir
);
5340 /* per cpu trace_pipe */
5341 trace_create_file("trace_pipe", 0444, d_cpu
,
5342 (void *)&data
->trace_cpu
, &tracing_pipe_fops
);
5345 trace_create_file("trace", 0644, d_cpu
,
5346 (void *)&data
->trace_cpu
, &tracing_fops
);
5348 trace_create_file("trace_pipe_raw", 0444, d_cpu
,
5349 (void *)&data
->trace_cpu
, &tracing_buffers_fops
);
5351 trace_create_file("stats", 0444, d_cpu
,
5352 (void *)&data
->trace_cpu
, &tracing_stats_fops
);
5354 trace_create_file("buffer_size_kb", 0444, d_cpu
,
5355 (void *)&data
->trace_cpu
, &tracing_entries_fops
);
5357 #ifdef CONFIG_TRACER_SNAPSHOT
5358 trace_create_file("snapshot", 0644, d_cpu
,
5359 (void *)&data
->trace_cpu
, &snapshot_fops
);
5361 trace_create_file("snapshot_raw", 0444, d_cpu
,
5362 (void *)&data
->trace_cpu
, &snapshot_raw_fops
);
5366 #ifdef CONFIG_FTRACE_SELFTEST
5367 /* Let selftest have access to static functions in this file */
5368 #include "trace_selftest.c"
5371 struct trace_option_dentry
{
5372 struct tracer_opt
*opt
;
5373 struct tracer_flags
*flags
;
5374 struct trace_array
*tr
;
5375 struct dentry
*entry
;
5379 trace_options_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
5382 struct trace_option_dentry
*topt
= filp
->private_data
;
5385 if (topt
->flags
->val
& topt
->opt
->bit
)
5390 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
5394 trace_options_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
5397 struct trace_option_dentry
*topt
= filp
->private_data
;
5401 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5405 if (val
!= 0 && val
!= 1)
5408 if (!!(topt
->flags
->val
& topt
->opt
->bit
) != val
) {
5409 mutex_lock(&trace_types_lock
);
5410 ret
= __set_tracer_option(topt
->tr
->current_trace
, topt
->flags
,
5412 mutex_unlock(&trace_types_lock
);
5423 static const struct file_operations trace_options_fops
= {
5424 .open
= tracing_open_generic
,
5425 .read
= trace_options_read
,
5426 .write
= trace_options_write
,
5427 .llseek
= generic_file_llseek
,
5431 trace_options_core_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
5434 long index
= (long)filp
->private_data
;
5437 if (trace_flags
& (1 << index
))
5442 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
5446 trace_options_core_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
5449 struct trace_array
*tr
= &global_trace
;
5450 long index
= (long)filp
->private_data
;
5454 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5458 if (val
!= 0 && val
!= 1)
5461 mutex_lock(&trace_types_lock
);
5462 ret
= set_tracer_flag(tr
, 1 << index
, val
);
5463 mutex_unlock(&trace_types_lock
);
5473 static const struct file_operations trace_options_core_fops
= {
5474 .open
= tracing_open_generic
,
5475 .read
= trace_options_core_read
,
5476 .write
= trace_options_core_write
,
5477 .llseek
= generic_file_llseek
,
5480 struct dentry
*trace_create_file(const char *name
,
5482 struct dentry
*parent
,
5484 const struct file_operations
*fops
)
5488 ret
= debugfs_create_file(name
, mode
, parent
, data
, fops
);
5490 pr_warning("Could not create debugfs '%s' entry\n", name
);
5496 static struct dentry
*trace_options_init_dentry(struct trace_array
*tr
)
5498 struct dentry
*d_tracer
;
5503 d_tracer
= tracing_init_dentry_tr(tr
);
5507 tr
->options
= debugfs_create_dir("options", d_tracer
);
5509 pr_warning("Could not create debugfs directory 'options'\n");
5517 create_trace_option_file(struct trace_array
*tr
,
5518 struct trace_option_dentry
*topt
,
5519 struct tracer_flags
*flags
,
5520 struct tracer_opt
*opt
)
5522 struct dentry
*t_options
;
5524 t_options
= trace_options_init_dentry(tr
);
5528 topt
->flags
= flags
;
5532 topt
->entry
= trace_create_file(opt
->name
, 0644, t_options
, topt
,
5533 &trace_options_fops
);
5537 static struct trace_option_dentry
*
5538 create_trace_option_files(struct trace_array
*tr
, struct tracer
*tracer
)
5540 struct trace_option_dentry
*topts
;
5541 struct tracer_flags
*flags
;
5542 struct tracer_opt
*opts
;
5548 flags
= tracer
->flags
;
5550 if (!flags
|| !flags
->opts
)
5555 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
5558 topts
= kcalloc(cnt
+ 1, sizeof(*topts
), GFP_KERNEL
);
5562 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
5563 create_trace_option_file(tr
, &topts
[cnt
], flags
,
5570 destroy_trace_option_files(struct trace_option_dentry
*topts
)
5577 for (cnt
= 0; topts
[cnt
].opt
; cnt
++) {
5578 if (topts
[cnt
].entry
)
5579 debugfs_remove(topts
[cnt
].entry
);
5585 static struct dentry
*
5586 create_trace_option_core_file(struct trace_array
*tr
,
5587 const char *option
, long index
)
5589 struct dentry
*t_options
;
5591 t_options
= trace_options_init_dentry(tr
);
5595 return trace_create_file(option
, 0644, t_options
, (void *)index
,
5596 &trace_options_core_fops
);
5599 static __init
void create_trace_options_dir(struct trace_array
*tr
)
5601 struct dentry
*t_options
;
5604 t_options
= trace_options_init_dentry(tr
);
5608 for (i
= 0; trace_options
[i
]; i
++)
5609 create_trace_option_core_file(tr
, trace_options
[i
], i
);
5613 rb_simple_read(struct file
*filp
, char __user
*ubuf
,
5614 size_t cnt
, loff_t
*ppos
)
5616 struct trace_array
*tr
= filp
->private_data
;
5617 struct ring_buffer
*buffer
= tr
->trace_buffer
.buffer
;
5622 r
= ring_buffer_record_is_on(buffer
);
5626 r
= sprintf(buf
, "%d\n", r
);
5628 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
5632 rb_simple_write(struct file
*filp
, const char __user
*ubuf
,
5633 size_t cnt
, loff_t
*ppos
)
5635 struct trace_array
*tr
= filp
->private_data
;
5636 struct ring_buffer
*buffer
= tr
->trace_buffer
.buffer
;
5640 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5645 mutex_lock(&trace_types_lock
);
5647 ring_buffer_record_on(buffer
);
5648 if (tr
->current_trace
->start
)
5649 tr
->current_trace
->start(tr
);
5651 ring_buffer_record_off(buffer
);
5652 if (tr
->current_trace
->stop
)
5653 tr
->current_trace
->stop(tr
);
5655 mutex_unlock(&trace_types_lock
);
5663 static const struct file_operations rb_simple_fops
= {
5664 .open
= tracing_open_generic
,
5665 .read
= rb_simple_read
,
5666 .write
= rb_simple_write
,
5667 .llseek
= default_llseek
,
5670 struct dentry
*trace_instance_dir
;
5673 init_tracer_debugfs(struct trace_array
*tr
, struct dentry
*d_tracer
);
5675 static void init_trace_buffers(struct trace_array
*tr
, struct trace_buffer
*buf
)
5679 for_each_tracing_cpu(cpu
) {
5680 memset(per_cpu_ptr(buf
->data
, cpu
), 0, sizeof(struct trace_array_cpu
));
5681 per_cpu_ptr(buf
->data
, cpu
)->trace_cpu
.cpu
= cpu
;
5682 per_cpu_ptr(buf
->data
, cpu
)->trace_cpu
.tr
= tr
;
5687 allocate_trace_buffer(struct trace_array
*tr
, struct trace_buffer
*buf
, int size
)
5689 enum ring_buffer_flags rb_flags
;
5691 rb_flags
= trace_flags
& TRACE_ITER_OVERWRITE
? RB_FL_OVERWRITE
: 0;
5693 buf
->buffer
= ring_buffer_alloc(size
, rb_flags
);
5697 buf
->data
= alloc_percpu(struct trace_array_cpu
);
5699 ring_buffer_free(buf
->buffer
);
5703 init_trace_buffers(tr
, buf
);
5705 /* Allocate the first page for all buffers */
5706 set_buffer_entries(&tr
->trace_buffer
,
5707 ring_buffer_size(tr
->trace_buffer
.buffer
, 0));
5712 static int allocate_trace_buffers(struct trace_array
*tr
, int size
)
5716 ret
= allocate_trace_buffer(tr
, &tr
->trace_buffer
, size
);
5720 #ifdef CONFIG_TRACER_MAX_TRACE
5721 ret
= allocate_trace_buffer(tr
, &tr
->max_buffer
,
5722 allocate_snapshot
? size
: 1);
5724 ring_buffer_free(tr
->trace_buffer
.buffer
);
5725 free_percpu(tr
->trace_buffer
.data
);
5728 tr
->allocated_snapshot
= allocate_snapshot
;
5731 * Only the top level trace array gets its snapshot allocated
5732 * from the kernel command line.
5734 allocate_snapshot
= false;
5739 static int new_instance_create(const char *name
)
5741 struct trace_array
*tr
;
5744 mutex_lock(&trace_types_lock
);
5747 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
5748 if (tr
->name
&& strcmp(tr
->name
, name
) == 0)
5753 tr
= kzalloc(sizeof(*tr
), GFP_KERNEL
);
5757 tr
->name
= kstrdup(name
, GFP_KERNEL
);
5761 raw_spin_lock_init(&tr
->start_lock
);
5763 tr
->current_trace
= &nop_trace
;
5765 INIT_LIST_HEAD(&tr
->systems
);
5766 INIT_LIST_HEAD(&tr
->events
);
5768 if (allocate_trace_buffers(tr
, trace_buf_size
) < 0)
5771 /* Holder for file callbacks */
5772 tr
->trace_cpu
.cpu
= RING_BUFFER_ALL_CPUS
;
5773 tr
->trace_cpu
.tr
= tr
;
5775 tr
->dir
= debugfs_create_dir(name
, trace_instance_dir
);
5779 ret
= event_trace_add_tracer(tr
->dir
, tr
);
5783 init_tracer_debugfs(tr
, tr
->dir
);
5785 list_add(&tr
->list
, &ftrace_trace_arrays
);
5787 mutex_unlock(&trace_types_lock
);
5792 if (tr
->trace_buffer
.buffer
)
5793 ring_buffer_free(tr
->trace_buffer
.buffer
);
5798 mutex_unlock(&trace_types_lock
);
5804 static int instance_delete(const char *name
)
5806 struct trace_array
*tr
;
5810 mutex_lock(&trace_types_lock
);
5813 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
5814 if (tr
->name
&& strcmp(tr
->name
, name
) == 0) {
5826 list_del(&tr
->list
);
5828 event_trace_del_tracer(tr
);
5829 debugfs_remove_recursive(tr
->dir
);
5830 free_percpu(tr
->trace_buffer
.data
);
5831 ring_buffer_free(tr
->trace_buffer
.buffer
);
5839 mutex_unlock(&trace_types_lock
);
5844 static int instance_mkdir (struct inode
*inode
, struct dentry
*dentry
, umode_t mode
)
5846 struct dentry
*parent
;
5849 /* Paranoid: Make sure the parent is the "instances" directory */
5850 parent
= hlist_entry(inode
->i_dentry
.first
, struct dentry
, d_alias
);
5851 if (WARN_ON_ONCE(parent
!= trace_instance_dir
))
5855 * The inode mutex is locked, but debugfs_create_dir() will also
5856 * take the mutex. As the instances directory can not be destroyed
5857 * or changed in any other way, it is safe to unlock it, and
5858 * let the dentry try. If two users try to make the same dir at
5859 * the same time, then the new_instance_create() will determine the
5862 mutex_unlock(&inode
->i_mutex
);
5864 ret
= new_instance_create(dentry
->d_iname
);
5866 mutex_lock(&inode
->i_mutex
);
5871 static int instance_rmdir(struct inode
*inode
, struct dentry
*dentry
)
5873 struct dentry
*parent
;
5876 /* Paranoid: Make sure the parent is the "instances" directory */
5877 parent
= hlist_entry(inode
->i_dentry
.first
, struct dentry
, d_alias
);
5878 if (WARN_ON_ONCE(parent
!= trace_instance_dir
))
5881 /* The caller did a dget() on dentry */
5882 mutex_unlock(&dentry
->d_inode
->i_mutex
);
5885 * The inode mutex is locked, but debugfs_create_dir() will also
5886 * take the mutex. As the instances directory can not be destroyed
5887 * or changed in any other way, it is safe to unlock it, and
5888 * let the dentry try. If two users try to make the same dir at
5889 * the same time, then the instance_delete() will determine the
5892 mutex_unlock(&inode
->i_mutex
);
5894 ret
= instance_delete(dentry
->d_iname
);
5896 mutex_lock_nested(&inode
->i_mutex
, I_MUTEX_PARENT
);
5897 mutex_lock(&dentry
->d_inode
->i_mutex
);
5902 static const struct inode_operations instance_dir_inode_operations
= {
5903 .lookup
= simple_lookup
,
5904 .mkdir
= instance_mkdir
,
5905 .rmdir
= instance_rmdir
,
5908 static __init
void create_trace_instances(struct dentry
*d_tracer
)
5910 trace_instance_dir
= debugfs_create_dir("instances", d_tracer
);
5911 if (WARN_ON(!trace_instance_dir
))
5914 /* Hijack the dir inode operations, to allow mkdir */
5915 trace_instance_dir
->d_inode
->i_op
= &instance_dir_inode_operations
;
5919 init_tracer_debugfs(struct trace_array
*tr
, struct dentry
*d_tracer
)
5923 trace_create_file("trace_options", 0644, d_tracer
,
5924 tr
, &tracing_iter_fops
);
5926 trace_create_file("trace", 0644, d_tracer
,
5927 (void *)&tr
->trace_cpu
, &tracing_fops
);
5929 trace_create_file("trace_pipe", 0444, d_tracer
,
5930 (void *)&tr
->trace_cpu
, &tracing_pipe_fops
);
5932 trace_create_file("buffer_size_kb", 0644, d_tracer
,
5933 (void *)&tr
->trace_cpu
, &tracing_entries_fops
);
5935 trace_create_file("buffer_total_size_kb", 0444, d_tracer
,
5936 tr
, &tracing_total_entries_fops
);
5938 trace_create_file("free_buffer", 0644, d_tracer
,
5939 tr
, &tracing_free_buffer_fops
);
5941 trace_create_file("trace_marker", 0220, d_tracer
,
5942 tr
, &tracing_mark_fops
);
5944 trace_create_file("trace_clock", 0644, d_tracer
, tr
,
5947 trace_create_file("tracing_on", 0644, d_tracer
,
5948 tr
, &rb_simple_fops
);
5950 #ifdef CONFIG_TRACER_SNAPSHOT
5951 trace_create_file("snapshot", 0644, d_tracer
,
5952 (void *)&tr
->trace_cpu
, &snapshot_fops
);
5955 for_each_tracing_cpu(cpu
)
5956 tracing_init_debugfs_percpu(tr
, cpu
);
5960 static __init
int tracer_init_debugfs(void)
5962 struct dentry
*d_tracer
;
5964 trace_access_lock_init();
5966 d_tracer
= tracing_init_dentry();
5970 init_tracer_debugfs(&global_trace
, d_tracer
);
5972 trace_create_file("tracing_cpumask", 0644, d_tracer
,
5973 &global_trace
, &tracing_cpumask_fops
);
5975 trace_create_file("available_tracers", 0444, d_tracer
,
5976 &global_trace
, &show_traces_fops
);
5978 trace_create_file("current_tracer", 0644, d_tracer
,
5979 &global_trace
, &set_tracer_fops
);
5981 #ifdef CONFIG_TRACER_MAX_TRACE
5982 trace_create_file("tracing_max_latency", 0644, d_tracer
,
5983 &tracing_max_latency
, &tracing_max_lat_fops
);
5986 trace_create_file("tracing_thresh", 0644, d_tracer
,
5987 &tracing_thresh
, &tracing_max_lat_fops
);
5989 trace_create_file("README", 0444, d_tracer
,
5990 NULL
, &tracing_readme_fops
);
5992 trace_create_file("saved_cmdlines", 0444, d_tracer
,
5993 NULL
, &tracing_saved_cmdlines_fops
);
5995 #ifdef CONFIG_DYNAMIC_FTRACE
5996 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
5997 &ftrace_update_tot_cnt
, &tracing_dyn_info_fops
);
6000 create_trace_instances(d_tracer
);
6002 create_trace_options_dir(&global_trace
);
6007 static int trace_panic_handler(struct notifier_block
*this,
6008 unsigned long event
, void *unused
)
6010 if (ftrace_dump_on_oops
)
6011 ftrace_dump(ftrace_dump_on_oops
);
6015 static struct notifier_block trace_panic_notifier
= {
6016 .notifier_call
= trace_panic_handler
,
6018 .priority
= 150 /* priority: INT_MAX >= x >= 0 */
6021 static int trace_die_handler(struct notifier_block
*self
,
6027 if (ftrace_dump_on_oops
)
6028 ftrace_dump(ftrace_dump_on_oops
);
6036 static struct notifier_block trace_die_notifier
= {
6037 .notifier_call
= trace_die_handler
,
6042 * printk is set to max of 1024, we really don't need it that big.
6043 * Nothing should be printing 1000 characters anyway.
6045 #define TRACE_MAX_PRINT 1000
6048 * Define here KERN_TRACE so that we have one place to modify
6049 * it if we decide to change what log level the ftrace dump
6052 #define KERN_TRACE KERN_EMERG
6055 trace_printk_seq(struct trace_seq
*s
)
6057 /* Probably should print a warning here. */
6058 if (s
->len
>= TRACE_MAX_PRINT
)
6059 s
->len
= TRACE_MAX_PRINT
;
6061 /* should be zero ended, but we are paranoid. */
6062 s
->buffer
[s
->len
] = 0;
6064 printk(KERN_TRACE
"%s", s
->buffer
);
6069 void trace_init_global_iter(struct trace_iterator
*iter
)
6071 iter
->tr
= &global_trace
;
6072 iter
->trace
= iter
->tr
->current_trace
;
6073 iter
->cpu_file
= RING_BUFFER_ALL_CPUS
;
6074 iter
->trace_buffer
= &global_trace
.trace_buffer
;
6077 void ftrace_dump(enum ftrace_dump_mode oops_dump_mode
)
6079 /* use static because iter can be a bit big for the stack */
6080 static struct trace_iterator iter
;
6081 static atomic_t dump_running
;
6082 unsigned int old_userobj
;
6083 unsigned long flags
;
6086 /* Only allow one dump user at a time. */
6087 if (atomic_inc_return(&dump_running
) != 1) {
6088 atomic_dec(&dump_running
);
6093 * Always turn off tracing when we dump.
6094 * We don't need to show trace output of what happens
6095 * between multiple crashes.
6097 * If the user does a sysrq-z, then they can re-enable
6098 * tracing with echo 1 > tracing_on.
6102 local_irq_save(flags
);
6104 /* Simulate the iterator */
6105 trace_init_global_iter(&iter
);
6107 for_each_tracing_cpu(cpu
) {
6108 atomic_inc(&per_cpu_ptr(iter
.tr
->trace_buffer
.data
, cpu
)->disabled
);
6111 old_userobj
= trace_flags
& TRACE_ITER_SYM_USEROBJ
;
6113 /* don't look at user memory in panic mode */
6114 trace_flags
&= ~TRACE_ITER_SYM_USEROBJ
;
6116 switch (oops_dump_mode
) {
6118 iter
.cpu_file
= RING_BUFFER_ALL_CPUS
;
6121 iter
.cpu_file
= raw_smp_processor_id();
6126 printk(KERN_TRACE
"Bad dumping mode, switching to all CPUs dump\n");
6127 iter
.cpu_file
= RING_BUFFER_ALL_CPUS
;
6130 printk(KERN_TRACE
"Dumping ftrace buffer:\n");
6132 /* Did function tracer already get disabled? */
6133 if (ftrace_is_dead()) {
6134 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
6135 printk("# MAY BE MISSING FUNCTION EVENTS\n");
6139 * We need to stop all tracing on all CPUS to read the
6140 * the next buffer. This is a bit expensive, but is
6141 * not done often. We fill all what we can read,
6142 * and then release the locks again.
6145 while (!trace_empty(&iter
)) {
6148 printk(KERN_TRACE
"---------------------------------\n");
6152 /* reset all but tr, trace, and overruns */
6153 memset(&iter
.seq
, 0,
6154 sizeof(struct trace_iterator
) -
6155 offsetof(struct trace_iterator
, seq
));
6156 iter
.iter_flags
|= TRACE_FILE_LAT_FMT
;
6159 if (trace_find_next_entry_inc(&iter
) != NULL
) {
6162 ret
= print_trace_line(&iter
);
6163 if (ret
!= TRACE_TYPE_NO_CONSUME
)
6164 trace_consume(&iter
);
6166 touch_nmi_watchdog();
6168 trace_printk_seq(&iter
.seq
);
6172 printk(KERN_TRACE
" (ftrace buffer empty)\n");
6174 printk(KERN_TRACE
"---------------------------------\n");
6177 trace_flags
|= old_userobj
;
6179 for_each_tracing_cpu(cpu
) {
6180 atomic_dec(&per_cpu_ptr(iter
.trace_buffer
->data
, cpu
)->disabled
);
6182 atomic_dec(&dump_running
);
6183 local_irq_restore(flags
);
6185 EXPORT_SYMBOL_GPL(ftrace_dump
);
6187 __init
static int tracer_alloc_buffers(void)
6193 if (!alloc_cpumask_var(&tracing_buffer_mask
, GFP_KERNEL
))
6196 if (!alloc_cpumask_var(&tracing_cpumask
, GFP_KERNEL
))
6197 goto out_free_buffer_mask
;
6199 /* Only allocate trace_printk buffers if a trace_printk exists */
6200 if (__stop___trace_bprintk_fmt
!= __start___trace_bprintk_fmt
)
6201 /* Must be called before global_trace.buffer is allocated */
6202 trace_printk_init_buffers();
6204 /* To save memory, keep the ring buffer size to its minimum */
6205 if (ring_buffer_expanded
)
6206 ring_buf_size
= trace_buf_size
;
6210 cpumask_copy(tracing_buffer_mask
, cpu_possible_mask
);
6211 cpumask_copy(tracing_cpumask
, cpu_all_mask
);
6213 raw_spin_lock_init(&global_trace
.start_lock
);
6215 /* TODO: make the number of buffers hot pluggable with CPUS */
6216 if (allocate_trace_buffers(&global_trace
, ring_buf_size
) < 0) {
6217 printk(KERN_ERR
"tracer: failed to allocate ring buffer!\n");
6219 goto out_free_cpumask
;
6222 if (global_trace
.buffer_disabled
)
6225 trace_init_cmdlines();
6228 * register_tracer() might reference current_trace, so it
6229 * needs to be set before we register anything. This is
6230 * just a bootstrap of current_trace anyway.
6232 global_trace
.current_trace
= &nop_trace
;
6234 register_tracer(&nop_trace
);
6236 /* All seems OK, enable tracing */
6237 tracing_disabled
= 0;
6239 atomic_notifier_chain_register(&panic_notifier_list
,
6240 &trace_panic_notifier
);
6242 register_die_notifier(&trace_die_notifier
);
6244 global_trace
.flags
= TRACE_ARRAY_FL_GLOBAL
;
6246 /* Holder for file callbacks */
6247 global_trace
.trace_cpu
.cpu
= RING_BUFFER_ALL_CPUS
;
6248 global_trace
.trace_cpu
.tr
= &global_trace
;
6250 INIT_LIST_HEAD(&global_trace
.systems
);
6251 INIT_LIST_HEAD(&global_trace
.events
);
6252 list_add(&global_trace
.list
, &ftrace_trace_arrays
);
6254 while (trace_boot_options
) {
6257 option
= strsep(&trace_boot_options
, ",");
6258 trace_set_options(&global_trace
, option
);
6261 register_snapshot_cmd();
6266 free_percpu(global_trace
.trace_buffer
.data
);
6267 #ifdef CONFIG_TRACER_MAX_TRACE
6268 free_percpu(global_trace
.max_buffer
.data
);
6270 free_cpumask_var(tracing_cpumask
);
6271 out_free_buffer_mask
:
6272 free_cpumask_var(tracing_buffer_mask
);
6277 __init
static int clear_boot_tracer(void)
6280 * The default tracer at boot buffer is an init section.
6281 * This function is called in lateinit. If we did not
6282 * find the boot tracer, then clear it out, to prevent
6283 * later registration from accessing the buffer that is
6284 * about to be freed.
6286 if (!default_bootup_tracer
)
6289 printk(KERN_INFO
"ftrace bootup tracer '%s' not registered.\n",
6290 default_bootup_tracer
);
6291 default_bootup_tracer
= NULL
;
6296 early_initcall(tracer_alloc_buffers
);
6297 fs_initcall(tracer_init_debugfs
);
6298 late_initcall(clear_boot_tracer
);