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
;
846 max_data
->uid
= task_uid(tsk
);
847 max_data
->nice
= tsk
->static_prio
- 20 - MAX_RT_PRIO
;
848 max_data
->policy
= tsk
->policy
;
849 max_data
->rt_priority
= tsk
->rt_priority
;
851 /* record this tasks comm */
852 tracing_record_cmdline(tsk
);
856 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
858 * @tsk: the task with the latency
859 * @cpu: The cpu that initiated the trace.
861 * Flip the buffers between the @tr and the max_tr and record information
862 * about which task was the cause of this latency.
865 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
867 struct ring_buffer
*buf
;
872 WARN_ON_ONCE(!irqs_disabled());
874 if (!tr
->allocated_snapshot
) {
875 /* Only the nop tracer should hit this when disabling */
876 WARN_ON_ONCE(tr
->current_trace
!= &nop_trace
);
880 arch_spin_lock(&ftrace_max_lock
);
882 buf
= tr
->trace_buffer
.buffer
;
883 tr
->trace_buffer
.buffer
= tr
->max_buffer
.buffer
;
884 tr
->max_buffer
.buffer
= buf
;
886 __update_max_tr(tr
, tsk
, cpu
);
887 arch_spin_unlock(&ftrace_max_lock
);
891 * update_max_tr_single - only copy one trace over, and reset the rest
893 * @tsk - task with the latency
894 * @cpu - the cpu of the buffer to copy.
896 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
899 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
906 WARN_ON_ONCE(!irqs_disabled());
907 if (!tr
->allocated_snapshot
) {
908 /* Only the nop tracer should hit this when disabling */
909 WARN_ON_ONCE(tr
->current_trace
!= &nop_trace
);
913 arch_spin_lock(&ftrace_max_lock
);
915 ret
= ring_buffer_swap_cpu(tr
->max_buffer
.buffer
, tr
->trace_buffer
.buffer
, cpu
);
919 * We failed to swap the buffer due to a commit taking
920 * place on this CPU. We fail to record, but we reset
921 * the max trace buffer (no one writes directly to it)
922 * and flag that it failed.
924 trace_array_printk_buf(tr
->max_buffer
.buffer
, _THIS_IP_
,
925 "Failed to swap buffers due to commit in progress\n");
928 WARN_ON_ONCE(ret
&& ret
!= -EAGAIN
&& ret
!= -EBUSY
);
930 __update_max_tr(tr
, tsk
, cpu
);
931 arch_spin_unlock(&ftrace_max_lock
);
933 #endif /* CONFIG_TRACER_MAX_TRACE */
935 static void default_wait_pipe(struct trace_iterator
*iter
)
937 /* Iterators are static, they should be filled or empty */
938 if (trace_buffer_iter(iter
, iter
->cpu_file
))
941 ring_buffer_wait(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
944 #ifdef CONFIG_FTRACE_STARTUP_TEST
945 static int run_tracer_selftest(struct tracer
*type
)
947 struct trace_array
*tr
= &global_trace
;
948 struct tracer
*saved_tracer
= tr
->current_trace
;
951 if (!type
->selftest
|| tracing_selftest_disabled
)
955 * Run a selftest on this tracer.
956 * Here we reset the trace buffer, and set the current
957 * tracer to be this tracer. The tracer can then run some
958 * internal tracing to verify that everything is in order.
959 * If we fail, we do not register this tracer.
961 tracing_reset_online_cpus(&tr
->trace_buffer
);
963 tr
->current_trace
= type
;
965 #ifdef CONFIG_TRACER_MAX_TRACE
966 if (type
->use_max_tr
) {
967 /* If we expanded the buffers, make sure the max is expanded too */
968 if (ring_buffer_expanded
)
969 ring_buffer_resize(tr
->max_buffer
.buffer
, trace_buf_size
,
970 RING_BUFFER_ALL_CPUS
);
971 tr
->allocated_snapshot
= true;
975 /* the test is responsible for initializing and enabling */
976 pr_info("Testing tracer %s: ", type
->name
);
977 ret
= type
->selftest(type
, tr
);
978 /* the test is responsible for resetting too */
979 tr
->current_trace
= saved_tracer
;
981 printk(KERN_CONT
"FAILED!\n");
982 /* Add the warning after printing 'FAILED' */
986 /* Only reset on passing, to avoid touching corrupted buffers */
987 tracing_reset_online_cpus(&tr
->trace_buffer
);
989 #ifdef CONFIG_TRACER_MAX_TRACE
990 if (type
->use_max_tr
) {
991 tr
->allocated_snapshot
= false;
993 /* Shrink the max buffer again */
994 if (ring_buffer_expanded
)
995 ring_buffer_resize(tr
->max_buffer
.buffer
, 1,
996 RING_BUFFER_ALL_CPUS
);
1000 printk(KERN_CONT
"PASSED\n");
1004 static inline int run_tracer_selftest(struct tracer
*type
)
1008 #endif /* CONFIG_FTRACE_STARTUP_TEST */
1011 * register_tracer - register a tracer with the ftrace system.
1012 * @type - the plugin for the tracer
1014 * Register a new plugin tracer.
1016 int register_tracer(struct tracer
*type
)
1022 pr_info("Tracer must have a name\n");
1026 if (strlen(type
->name
) >= MAX_TRACER_SIZE
) {
1027 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE
);
1031 mutex_lock(&trace_types_lock
);
1033 tracing_selftest_running
= true;
1035 for (t
= trace_types
; t
; t
= t
->next
) {
1036 if (strcmp(type
->name
, t
->name
) == 0) {
1038 pr_info("Tracer %s already registered\n",
1045 if (!type
->set_flag
)
1046 type
->set_flag
= &dummy_set_flag
;
1048 type
->flags
= &dummy_tracer_flags
;
1050 if (!type
->flags
->opts
)
1051 type
->flags
->opts
= dummy_tracer_opt
;
1052 if (!type
->wait_pipe
)
1053 type
->wait_pipe
= default_wait_pipe
;
1055 ret
= run_tracer_selftest(type
);
1059 type
->next
= trace_types
;
1063 tracing_selftest_running
= false;
1064 mutex_unlock(&trace_types_lock
);
1066 if (ret
|| !default_bootup_tracer
)
1069 if (strncmp(default_bootup_tracer
, type
->name
, MAX_TRACER_SIZE
))
1072 printk(KERN_INFO
"Starting tracer '%s'\n", type
->name
);
1073 /* Do we want this tracer to start on bootup? */
1074 tracing_set_tracer(type
->name
);
1075 default_bootup_tracer
= NULL
;
1076 /* disable other selftests, since this will break it. */
1077 tracing_selftest_disabled
= true;
1078 #ifdef CONFIG_FTRACE_STARTUP_TEST
1079 printk(KERN_INFO
"Disabling FTRACE selftests due to running tracer '%s'\n",
1087 void tracing_reset(struct trace_buffer
*buf
, int cpu
)
1089 struct ring_buffer
*buffer
= buf
->buffer
;
1094 ring_buffer_record_disable(buffer
);
1096 /* Make sure all commits have finished */
1097 synchronize_sched();
1098 ring_buffer_reset_cpu(buffer
, cpu
);
1100 ring_buffer_record_enable(buffer
);
1103 void tracing_reset_online_cpus(struct trace_buffer
*buf
)
1105 struct ring_buffer
*buffer
= buf
->buffer
;
1111 ring_buffer_record_disable(buffer
);
1113 /* Make sure all commits have finished */
1114 synchronize_sched();
1116 buf
->time_start
= ftrace_now(buf
->cpu
);
1118 for_each_online_cpu(cpu
)
1119 ring_buffer_reset_cpu(buffer
, cpu
);
1121 ring_buffer_record_enable(buffer
);
1124 void tracing_reset_current(int cpu
)
1126 tracing_reset(&global_trace
.trace_buffer
, cpu
);
1129 void tracing_reset_all_online_cpus(void)
1131 struct trace_array
*tr
;
1133 mutex_lock(&trace_types_lock
);
1134 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
1135 tracing_reset_online_cpus(&tr
->trace_buffer
);
1136 #ifdef CONFIG_TRACER_MAX_TRACE
1137 tracing_reset_online_cpus(&tr
->max_buffer
);
1140 mutex_unlock(&trace_types_lock
);
1143 #define SAVED_CMDLINES 128
1144 #define NO_CMDLINE_MAP UINT_MAX
1145 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
1146 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
1147 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
1148 static int cmdline_idx
;
1149 static arch_spinlock_t trace_cmdline_lock
= __ARCH_SPIN_LOCK_UNLOCKED
;
1151 /* temporary disable recording */
1152 static atomic_t trace_record_cmdline_disabled __read_mostly
;
1154 static void trace_init_cmdlines(void)
1156 memset(&map_pid_to_cmdline
, NO_CMDLINE_MAP
, sizeof(map_pid_to_cmdline
));
1157 memset(&map_cmdline_to_pid
, NO_CMDLINE_MAP
, sizeof(map_cmdline_to_pid
));
1161 int is_tracing_stopped(void)
1163 return global_trace
.stop_count
;
1167 * ftrace_off_permanent - disable all ftrace code permanently
1169 * This should only be called when a serious anomally has
1170 * been detected. This will turn off the function tracing,
1171 * ring buffers, and other tracing utilites. It takes no
1172 * locks and can be called from any context.
1174 void ftrace_off_permanent(void)
1176 tracing_disabled
= 1;
1178 tracing_off_permanent();
1182 * tracing_start - quick start of the tracer
1184 * If tracing is enabled but was stopped by tracing_stop,
1185 * this will start the tracer back up.
1187 void tracing_start(void)
1189 struct ring_buffer
*buffer
;
1190 unsigned long flags
;
1192 if (tracing_disabled
)
1195 raw_spin_lock_irqsave(&global_trace
.start_lock
, flags
);
1196 if (--global_trace
.stop_count
) {
1197 if (global_trace
.stop_count
< 0) {
1198 /* Someone screwed up their debugging */
1200 global_trace
.stop_count
= 0;
1205 /* Prevent the buffers from switching */
1206 arch_spin_lock(&ftrace_max_lock
);
1208 buffer
= global_trace
.trace_buffer
.buffer
;
1210 ring_buffer_record_enable(buffer
);
1212 #ifdef CONFIG_TRACER_MAX_TRACE
1213 buffer
= global_trace
.max_buffer
.buffer
;
1215 ring_buffer_record_enable(buffer
);
1218 arch_spin_unlock(&ftrace_max_lock
);
1222 raw_spin_unlock_irqrestore(&global_trace
.start_lock
, flags
);
1225 static void tracing_start_tr(struct trace_array
*tr
)
1227 struct ring_buffer
*buffer
;
1228 unsigned long flags
;
1230 if (tracing_disabled
)
1233 /* If global, we need to also start the max tracer */
1234 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
1235 return tracing_start();
1237 raw_spin_lock_irqsave(&tr
->start_lock
, flags
);
1239 if (--tr
->stop_count
) {
1240 if (tr
->stop_count
< 0) {
1241 /* Someone screwed up their debugging */
1248 buffer
= tr
->trace_buffer
.buffer
;
1250 ring_buffer_record_enable(buffer
);
1253 raw_spin_unlock_irqrestore(&tr
->start_lock
, flags
);
1257 * tracing_stop - quick stop of the tracer
1259 * Light weight way to stop tracing. Use in conjunction with
1262 void tracing_stop(void)
1264 struct ring_buffer
*buffer
;
1265 unsigned long flags
;
1268 raw_spin_lock_irqsave(&global_trace
.start_lock
, flags
);
1269 if (global_trace
.stop_count
++)
1272 /* Prevent the buffers from switching */
1273 arch_spin_lock(&ftrace_max_lock
);
1275 buffer
= global_trace
.trace_buffer
.buffer
;
1277 ring_buffer_record_disable(buffer
);
1279 #ifdef CONFIG_TRACER_MAX_TRACE
1280 buffer
= global_trace
.max_buffer
.buffer
;
1282 ring_buffer_record_disable(buffer
);
1285 arch_spin_unlock(&ftrace_max_lock
);
1288 raw_spin_unlock_irqrestore(&global_trace
.start_lock
, flags
);
1291 static void tracing_stop_tr(struct trace_array
*tr
)
1293 struct ring_buffer
*buffer
;
1294 unsigned long flags
;
1296 /* If global, we need to also stop the max tracer */
1297 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
1298 return tracing_stop();
1300 raw_spin_lock_irqsave(&tr
->start_lock
, flags
);
1301 if (tr
->stop_count
++)
1304 buffer
= tr
->trace_buffer
.buffer
;
1306 ring_buffer_record_disable(buffer
);
1309 raw_spin_unlock_irqrestore(&tr
->start_lock
, flags
);
1312 void trace_stop_cmdline_recording(void);
1314 static void trace_save_cmdline(struct task_struct
*tsk
)
1318 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
1322 * It's not the end of the world if we don't get
1323 * the lock, but we also don't want to spin
1324 * nor do we want to disable interrupts,
1325 * so if we miss here, then better luck next time.
1327 if (!arch_spin_trylock(&trace_cmdline_lock
))
1330 idx
= map_pid_to_cmdline
[tsk
->pid
];
1331 if (idx
== NO_CMDLINE_MAP
) {
1332 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
1335 * Check whether the cmdline buffer at idx has a pid
1336 * mapped. We are going to overwrite that entry so we
1337 * need to clear the map_pid_to_cmdline. Otherwise we
1338 * would read the new comm for the old pid.
1340 pid
= map_cmdline_to_pid
[idx
];
1341 if (pid
!= NO_CMDLINE_MAP
)
1342 map_pid_to_cmdline
[pid
] = NO_CMDLINE_MAP
;
1344 map_cmdline_to_pid
[idx
] = tsk
->pid
;
1345 map_pid_to_cmdline
[tsk
->pid
] = idx
;
1350 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
1352 arch_spin_unlock(&trace_cmdline_lock
);
1355 void trace_find_cmdline(int pid
, char comm
[])
1360 strcpy(comm
, "<idle>");
1364 if (WARN_ON_ONCE(pid
< 0)) {
1365 strcpy(comm
, "<XXX>");
1369 if (pid
> PID_MAX_DEFAULT
) {
1370 strcpy(comm
, "<...>");
1375 arch_spin_lock(&trace_cmdline_lock
);
1376 map
= map_pid_to_cmdline
[pid
];
1377 if (map
!= NO_CMDLINE_MAP
)
1378 strcpy(comm
, saved_cmdlines
[map
]);
1380 strcpy(comm
, "<...>");
1382 arch_spin_unlock(&trace_cmdline_lock
);
1386 void tracing_record_cmdline(struct task_struct
*tsk
)
1388 if (atomic_read(&trace_record_cmdline_disabled
) || !tracing_is_on())
1391 if (!__this_cpu_read(trace_cmdline_save
))
1394 __this_cpu_write(trace_cmdline_save
, false);
1396 trace_save_cmdline(tsk
);
1400 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
,
1403 struct task_struct
*tsk
= current
;
1405 entry
->preempt_count
= pc
& 0xff;
1406 entry
->pid
= (tsk
) ? tsk
->pid
: 0;
1408 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1409 (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
1411 TRACE_FLAG_IRQS_NOSUPPORT
|
1413 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
1414 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
1415 (need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0);
1417 EXPORT_SYMBOL_GPL(tracing_generic_entry_update
);
1419 struct ring_buffer_event
*
1420 trace_buffer_lock_reserve(struct ring_buffer
*buffer
,
1423 unsigned long flags
, int pc
)
1425 struct ring_buffer_event
*event
;
1427 event
= ring_buffer_lock_reserve(buffer
, len
);
1428 if (event
!= NULL
) {
1429 struct trace_entry
*ent
= ring_buffer_event_data(event
);
1431 tracing_generic_entry_update(ent
, flags
, pc
);
1439 __buffer_unlock_commit(struct ring_buffer
*buffer
, struct ring_buffer_event
*event
)
1441 __this_cpu_write(trace_cmdline_save
, true);
1442 ring_buffer_unlock_commit(buffer
, event
);
1446 __trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1447 struct ring_buffer_event
*event
,
1448 unsigned long flags
, int pc
)
1450 __buffer_unlock_commit(buffer
, event
);
1452 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1453 ftrace_trace_userstack(buffer
, flags
, pc
);
1456 void trace_buffer_unlock_commit(struct ring_buffer
*buffer
,
1457 struct ring_buffer_event
*event
,
1458 unsigned long flags
, int pc
)
1460 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
);
1462 EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit
);
1464 struct ring_buffer_event
*
1465 trace_event_buffer_lock_reserve(struct ring_buffer
**current_rb
,
1466 struct ftrace_event_file
*ftrace_file
,
1467 int type
, unsigned long len
,
1468 unsigned long flags
, int pc
)
1470 *current_rb
= ftrace_file
->tr
->trace_buffer
.buffer
;
1471 return trace_buffer_lock_reserve(*current_rb
,
1472 type
, len
, flags
, pc
);
1474 EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve
);
1476 struct ring_buffer_event
*
1477 trace_current_buffer_lock_reserve(struct ring_buffer
**current_rb
,
1478 int type
, unsigned long len
,
1479 unsigned long flags
, int pc
)
1481 *current_rb
= global_trace
.trace_buffer
.buffer
;
1482 return trace_buffer_lock_reserve(*current_rb
,
1483 type
, len
, flags
, pc
);
1485 EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve
);
1487 void trace_current_buffer_unlock_commit(struct ring_buffer
*buffer
,
1488 struct ring_buffer_event
*event
,
1489 unsigned long flags
, int pc
)
1491 __trace_buffer_unlock_commit(buffer
, event
, flags
, pc
);
1493 EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit
);
1495 void trace_buffer_unlock_commit_regs(struct ring_buffer
*buffer
,
1496 struct ring_buffer_event
*event
,
1497 unsigned long flags
, int pc
,
1498 struct pt_regs
*regs
)
1500 __buffer_unlock_commit(buffer
, event
);
1502 ftrace_trace_stack_regs(buffer
, flags
, 0, pc
, regs
);
1503 ftrace_trace_userstack(buffer
, flags
, pc
);
1505 EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit_regs
);
1507 void trace_current_buffer_discard_commit(struct ring_buffer
*buffer
,
1508 struct ring_buffer_event
*event
)
1510 ring_buffer_discard_commit(buffer
, event
);
1512 EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit
);
1515 trace_function(struct trace_array
*tr
,
1516 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
1519 struct ftrace_event_call
*call
= &event_function
;
1520 struct ring_buffer
*buffer
= tr
->trace_buffer
.buffer
;
1521 struct ring_buffer_event
*event
;
1522 struct ftrace_entry
*entry
;
1524 /* If we are reading the ring buffer, don't trace */
1525 if (unlikely(__this_cpu_read(ftrace_cpu_disabled
)))
1528 event
= trace_buffer_lock_reserve(buffer
, TRACE_FN
, sizeof(*entry
),
1532 entry
= ring_buffer_event_data(event
);
1534 entry
->parent_ip
= parent_ip
;
1536 if (!filter_check_discard(call
, entry
, buffer
, event
))
1537 __buffer_unlock_commit(buffer
, event
);
1541 ftrace(struct trace_array
*tr
, struct trace_array_cpu
*data
,
1542 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
1545 if (likely(!atomic_read(&data
->disabled
)))
1546 trace_function(tr
, ip
, parent_ip
, flags
, pc
);
1549 #ifdef CONFIG_STACKTRACE
1551 #define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
1552 struct ftrace_stack
{
1553 unsigned long calls
[FTRACE_STACK_MAX_ENTRIES
];
1556 static DEFINE_PER_CPU(struct ftrace_stack
, ftrace_stack
);
1557 static DEFINE_PER_CPU(int, ftrace_stack_reserve
);
1559 static void __ftrace_trace_stack(struct ring_buffer
*buffer
,
1560 unsigned long flags
,
1561 int skip
, int pc
, struct pt_regs
*regs
)
1563 struct ftrace_event_call
*call
= &event_kernel_stack
;
1564 struct ring_buffer_event
*event
;
1565 struct stack_entry
*entry
;
1566 struct stack_trace trace
;
1568 int size
= FTRACE_STACK_ENTRIES
;
1570 trace
.nr_entries
= 0;
1574 * Since events can happen in NMIs there's no safe way to
1575 * use the per cpu ftrace_stacks. We reserve it and if an interrupt
1576 * or NMI comes in, it will just have to use the default
1577 * FTRACE_STACK_SIZE.
1579 preempt_disable_notrace();
1581 use_stack
= __this_cpu_inc_return(ftrace_stack_reserve
);
1583 * We don't need any atomic variables, just a barrier.
1584 * If an interrupt comes in, we don't care, because it would
1585 * have exited and put the counter back to what we want.
1586 * We just need a barrier to keep gcc from moving things
1590 if (use_stack
== 1) {
1591 trace
.entries
= &__get_cpu_var(ftrace_stack
).calls
[0];
1592 trace
.max_entries
= FTRACE_STACK_MAX_ENTRIES
;
1595 save_stack_trace_regs(regs
, &trace
);
1597 save_stack_trace(&trace
);
1599 if (trace
.nr_entries
> size
)
1600 size
= trace
.nr_entries
;
1602 /* From now on, use_stack is a boolean */
1605 size
*= sizeof(unsigned long);
1607 event
= trace_buffer_lock_reserve(buffer
, TRACE_STACK
,
1608 sizeof(*entry
) + size
, flags
, pc
);
1611 entry
= ring_buffer_event_data(event
);
1613 memset(&entry
->caller
, 0, size
);
1616 memcpy(&entry
->caller
, trace
.entries
,
1617 trace
.nr_entries
* sizeof(unsigned long));
1619 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1620 trace
.entries
= entry
->caller
;
1622 save_stack_trace_regs(regs
, &trace
);
1624 save_stack_trace(&trace
);
1627 entry
->size
= trace
.nr_entries
;
1629 if (!filter_check_discard(call
, entry
, buffer
, event
))
1630 __buffer_unlock_commit(buffer
, event
);
1633 /* Again, don't let gcc optimize things here */
1635 __this_cpu_dec(ftrace_stack_reserve
);
1636 preempt_enable_notrace();
1640 void ftrace_trace_stack_regs(struct ring_buffer
*buffer
, unsigned long flags
,
1641 int skip
, int pc
, struct pt_regs
*regs
)
1643 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1646 __ftrace_trace_stack(buffer
, flags
, skip
, pc
, regs
);
1649 void ftrace_trace_stack(struct ring_buffer
*buffer
, unsigned long flags
,
1652 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
1655 __ftrace_trace_stack(buffer
, flags
, skip
, pc
, NULL
);
1658 void __trace_stack(struct trace_array
*tr
, unsigned long flags
, int skip
,
1661 __ftrace_trace_stack(tr
->trace_buffer
.buffer
, flags
, skip
, pc
, NULL
);
1665 * trace_dump_stack - record a stack back trace in the trace buffer
1666 * @skip: Number of functions to skip (helper handlers)
1668 void trace_dump_stack(int skip
)
1670 unsigned long flags
;
1672 if (tracing_disabled
|| tracing_selftest_running
)
1675 local_save_flags(flags
);
1678 * Skip 3 more, seems to get us at the caller of
1682 __ftrace_trace_stack(global_trace
.trace_buffer
.buffer
,
1683 flags
, skip
, preempt_count(), NULL
);
1686 static DEFINE_PER_CPU(int, user_stack_count
);
1689 ftrace_trace_userstack(struct ring_buffer
*buffer
, unsigned long flags
, int pc
)
1691 struct ftrace_event_call
*call
= &event_user_stack
;
1692 struct ring_buffer_event
*event
;
1693 struct userstack_entry
*entry
;
1694 struct stack_trace trace
;
1696 if (!(trace_flags
& TRACE_ITER_USERSTACKTRACE
))
1700 * NMIs can not handle page faults, even with fix ups.
1701 * The save user stack can (and often does) fault.
1703 if (unlikely(in_nmi()))
1707 * prevent recursion, since the user stack tracing may
1708 * trigger other kernel events.
1711 if (__this_cpu_read(user_stack_count
))
1714 __this_cpu_inc(user_stack_count
);
1716 event
= trace_buffer_lock_reserve(buffer
, TRACE_USER_STACK
,
1717 sizeof(*entry
), flags
, pc
);
1719 goto out_drop_count
;
1720 entry
= ring_buffer_event_data(event
);
1722 entry
->tgid
= current
->tgid
;
1723 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
1725 trace
.nr_entries
= 0;
1726 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
1728 trace
.entries
= entry
->caller
;
1730 save_stack_trace_user(&trace
);
1731 if (!filter_check_discard(call
, entry
, buffer
, event
))
1732 __buffer_unlock_commit(buffer
, event
);
1735 __this_cpu_dec(user_stack_count
);
1741 static void __trace_userstack(struct trace_array
*tr
, unsigned long flags
)
1743 ftrace_trace_userstack(tr
, flags
, preempt_count());
1747 #endif /* CONFIG_STACKTRACE */
1749 /* created for use with alloc_percpu */
1750 struct trace_buffer_struct
{
1751 char buffer
[TRACE_BUF_SIZE
];
1754 static struct trace_buffer_struct
*trace_percpu_buffer
;
1755 static struct trace_buffer_struct
*trace_percpu_sirq_buffer
;
1756 static struct trace_buffer_struct
*trace_percpu_irq_buffer
;
1757 static struct trace_buffer_struct
*trace_percpu_nmi_buffer
;
1760 * The buffer used is dependent on the context. There is a per cpu
1761 * buffer for normal context, softirq contex, hard irq context and
1762 * for NMI context. Thise allows for lockless recording.
1764 * Note, if the buffers failed to be allocated, then this returns NULL
1766 static char *get_trace_buf(void)
1768 struct trace_buffer_struct
*percpu_buffer
;
1771 * If we have allocated per cpu buffers, then we do not
1772 * need to do any locking.
1775 percpu_buffer
= trace_percpu_nmi_buffer
;
1777 percpu_buffer
= trace_percpu_irq_buffer
;
1778 else if (in_softirq())
1779 percpu_buffer
= trace_percpu_sirq_buffer
;
1781 percpu_buffer
= trace_percpu_buffer
;
1786 return this_cpu_ptr(&percpu_buffer
->buffer
[0]);
1789 static int alloc_percpu_trace_buffer(void)
1791 struct trace_buffer_struct
*buffers
;
1792 struct trace_buffer_struct
*sirq_buffers
;
1793 struct trace_buffer_struct
*irq_buffers
;
1794 struct trace_buffer_struct
*nmi_buffers
;
1796 buffers
= alloc_percpu(struct trace_buffer_struct
);
1800 sirq_buffers
= alloc_percpu(struct trace_buffer_struct
);
1804 irq_buffers
= alloc_percpu(struct trace_buffer_struct
);
1808 nmi_buffers
= alloc_percpu(struct trace_buffer_struct
);
1812 trace_percpu_buffer
= buffers
;
1813 trace_percpu_sirq_buffer
= sirq_buffers
;
1814 trace_percpu_irq_buffer
= irq_buffers
;
1815 trace_percpu_nmi_buffer
= nmi_buffers
;
1820 free_percpu(irq_buffers
);
1822 free_percpu(sirq_buffers
);
1824 free_percpu(buffers
);
1826 WARN(1, "Could not allocate percpu trace_printk buffer");
1830 static int buffers_allocated
;
1832 void trace_printk_init_buffers(void)
1834 if (buffers_allocated
)
1837 if (alloc_percpu_trace_buffer())
1840 pr_info("ftrace: Allocated trace_printk buffers\n");
1842 /* Expand the buffers to set size */
1843 tracing_update_buffers();
1845 buffers_allocated
= 1;
1848 * trace_printk_init_buffers() can be called by modules.
1849 * If that happens, then we need to start cmdline recording
1850 * directly here. If the global_trace.buffer is already
1851 * allocated here, then this was called by module code.
1853 if (global_trace
.trace_buffer
.buffer
)
1854 tracing_start_cmdline_record();
1857 void trace_printk_start_comm(void)
1859 /* Start tracing comms if trace printk is set */
1860 if (!buffers_allocated
)
1862 tracing_start_cmdline_record();
1865 static void trace_printk_start_stop_comm(int enabled
)
1867 if (!buffers_allocated
)
1871 tracing_start_cmdline_record();
1873 tracing_stop_cmdline_record();
1877 * trace_vbprintk - write binary msg to tracing buffer
1880 int trace_vbprintk(unsigned long ip
, const char *fmt
, va_list args
)
1882 struct ftrace_event_call
*call
= &event_bprint
;
1883 struct ring_buffer_event
*event
;
1884 struct ring_buffer
*buffer
;
1885 struct trace_array
*tr
= &global_trace
;
1886 struct bprint_entry
*entry
;
1887 unsigned long flags
;
1889 int len
= 0, size
, pc
;
1891 if (unlikely(tracing_selftest_running
|| tracing_disabled
))
1894 /* Don't pollute graph traces with trace_vprintk internals */
1895 pause_graph_tracing();
1897 pc
= preempt_count();
1898 preempt_disable_notrace();
1900 tbuffer
= get_trace_buf();
1906 len
= vbin_printf((u32
*)tbuffer
, TRACE_BUF_SIZE
/sizeof(int), fmt
, args
);
1908 if (len
> TRACE_BUF_SIZE
/sizeof(int) || len
< 0)
1911 local_save_flags(flags
);
1912 size
= sizeof(*entry
) + sizeof(u32
) * len
;
1913 buffer
= tr
->trace_buffer
.buffer
;
1914 event
= trace_buffer_lock_reserve(buffer
, TRACE_BPRINT
, size
,
1918 entry
= ring_buffer_event_data(event
);
1922 memcpy(entry
->buf
, tbuffer
, sizeof(u32
) * len
);
1923 if (!filter_check_discard(call
, entry
, buffer
, event
)) {
1924 __buffer_unlock_commit(buffer
, event
);
1925 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1929 preempt_enable_notrace();
1930 unpause_graph_tracing();
1934 EXPORT_SYMBOL_GPL(trace_vbprintk
);
1937 __trace_array_vprintk(struct ring_buffer
*buffer
,
1938 unsigned long ip
, const char *fmt
, va_list args
)
1940 struct ftrace_event_call
*call
= &event_print
;
1941 struct ring_buffer_event
*event
;
1942 int len
= 0, size
, pc
;
1943 struct print_entry
*entry
;
1944 unsigned long flags
;
1947 if (tracing_disabled
|| tracing_selftest_running
)
1950 /* Don't pollute graph traces with trace_vprintk internals */
1951 pause_graph_tracing();
1953 pc
= preempt_count();
1954 preempt_disable_notrace();
1957 tbuffer
= get_trace_buf();
1963 len
= vsnprintf(tbuffer
, TRACE_BUF_SIZE
, fmt
, args
);
1964 if (len
> TRACE_BUF_SIZE
)
1967 local_save_flags(flags
);
1968 size
= sizeof(*entry
) + len
+ 1;
1969 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, size
,
1973 entry
= ring_buffer_event_data(event
);
1976 memcpy(&entry
->buf
, tbuffer
, len
);
1977 entry
->buf
[len
] = '\0';
1978 if (!filter_check_discard(call
, entry
, buffer
, event
)) {
1979 __buffer_unlock_commit(buffer
, event
);
1980 ftrace_trace_stack(buffer
, flags
, 6, pc
);
1983 preempt_enable_notrace();
1984 unpause_graph_tracing();
1989 int trace_array_vprintk(struct trace_array
*tr
,
1990 unsigned long ip
, const char *fmt
, va_list args
)
1992 return __trace_array_vprintk(tr
->trace_buffer
.buffer
, ip
, fmt
, args
);
1995 int trace_array_printk(struct trace_array
*tr
,
1996 unsigned long ip
, const char *fmt
, ...)
2001 if (!(trace_flags
& TRACE_ITER_PRINTK
))
2005 ret
= trace_array_vprintk(tr
, ip
, fmt
, ap
);
2010 int trace_array_printk_buf(struct ring_buffer
*buffer
,
2011 unsigned long ip
, const char *fmt
, ...)
2016 if (!(trace_flags
& TRACE_ITER_PRINTK
))
2020 ret
= __trace_array_vprintk(buffer
, ip
, fmt
, ap
);
2025 int trace_vprintk(unsigned long ip
, const char *fmt
, va_list args
)
2027 return trace_array_vprintk(&global_trace
, ip
, fmt
, args
);
2029 EXPORT_SYMBOL_GPL(trace_vprintk
);
2031 static void trace_iterator_increment(struct trace_iterator
*iter
)
2033 struct ring_buffer_iter
*buf_iter
= trace_buffer_iter(iter
, iter
->cpu
);
2037 ring_buffer_read(buf_iter
, NULL
);
2040 static struct trace_entry
*
2041 peek_next_entry(struct trace_iterator
*iter
, int cpu
, u64
*ts
,
2042 unsigned long *lost_events
)
2044 struct ring_buffer_event
*event
;
2045 struct ring_buffer_iter
*buf_iter
= trace_buffer_iter(iter
, cpu
);
2048 event
= ring_buffer_iter_peek(buf_iter
, ts
);
2050 event
= ring_buffer_peek(iter
->trace_buffer
->buffer
, cpu
, ts
,
2054 iter
->ent_size
= ring_buffer_event_length(event
);
2055 return ring_buffer_event_data(event
);
2061 static struct trace_entry
*
2062 __find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
,
2063 unsigned long *missing_events
, u64
*ent_ts
)
2065 struct ring_buffer
*buffer
= iter
->trace_buffer
->buffer
;
2066 struct trace_entry
*ent
, *next
= NULL
;
2067 unsigned long lost_events
= 0, next_lost
= 0;
2068 int cpu_file
= iter
->cpu_file
;
2069 u64 next_ts
= 0, ts
;
2075 * If we are in a per_cpu trace file, don't bother by iterating over
2076 * all cpu and peek directly.
2078 if (cpu_file
> RING_BUFFER_ALL_CPUS
) {
2079 if (ring_buffer_empty_cpu(buffer
, cpu_file
))
2081 ent
= peek_next_entry(iter
, cpu_file
, ent_ts
, missing_events
);
2083 *ent_cpu
= cpu_file
;
2088 for_each_tracing_cpu(cpu
) {
2090 if (ring_buffer_empty_cpu(buffer
, cpu
))
2093 ent
= peek_next_entry(iter
, cpu
, &ts
, &lost_events
);
2096 * Pick the entry with the smallest timestamp:
2098 if (ent
&& (!next
|| ts
< next_ts
)) {
2102 next_lost
= lost_events
;
2103 next_size
= iter
->ent_size
;
2107 iter
->ent_size
= next_size
;
2110 *ent_cpu
= next_cpu
;
2116 *missing_events
= next_lost
;
2121 /* Find the next real entry, without updating the iterator itself */
2122 struct trace_entry
*trace_find_next_entry(struct trace_iterator
*iter
,
2123 int *ent_cpu
, u64
*ent_ts
)
2125 return __find_next_entry(iter
, ent_cpu
, NULL
, ent_ts
);
2128 /* Find the next real entry, and increment the iterator to the next entry */
2129 void *trace_find_next_entry_inc(struct trace_iterator
*iter
)
2131 iter
->ent
= __find_next_entry(iter
, &iter
->cpu
,
2132 &iter
->lost_events
, &iter
->ts
);
2135 trace_iterator_increment(iter
);
2137 return iter
->ent
? iter
: NULL
;
2140 static void trace_consume(struct trace_iterator
*iter
)
2142 ring_buffer_consume(iter
->trace_buffer
->buffer
, iter
->cpu
, &iter
->ts
,
2143 &iter
->lost_events
);
2146 static void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
2148 struct trace_iterator
*iter
= m
->private;
2152 WARN_ON_ONCE(iter
->leftover
);
2156 /* can't go backwards */
2161 ent
= trace_find_next_entry_inc(iter
);
2165 while (ent
&& iter
->idx
< i
)
2166 ent
= trace_find_next_entry_inc(iter
);
2173 void tracing_iter_reset(struct trace_iterator
*iter
, int cpu
)
2175 struct ring_buffer_event
*event
;
2176 struct ring_buffer_iter
*buf_iter
;
2177 unsigned long entries
= 0;
2180 per_cpu_ptr(iter
->trace_buffer
->data
, cpu
)->skipped_entries
= 0;
2182 buf_iter
= trace_buffer_iter(iter
, cpu
);
2186 ring_buffer_iter_reset(buf_iter
);
2189 * We could have the case with the max latency tracers
2190 * that a reset never took place on a cpu. This is evident
2191 * by the timestamp being before the start of the buffer.
2193 while ((event
= ring_buffer_iter_peek(buf_iter
, &ts
))) {
2194 if (ts
>= iter
->trace_buffer
->time_start
)
2197 ring_buffer_read(buf_iter
, NULL
);
2200 per_cpu_ptr(iter
->trace_buffer
->data
, cpu
)->skipped_entries
= entries
;
2204 * The current tracer is copied to avoid a global locking
2207 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
2209 struct trace_iterator
*iter
= m
->private;
2210 struct trace_array
*tr
= iter
->tr
;
2211 int cpu_file
= iter
->cpu_file
;
2217 * copy the tracer to avoid using a global lock all around.
2218 * iter->trace is a copy of current_trace, the pointer to the
2219 * name may be used instead of a strcmp(), as iter->trace->name
2220 * will point to the same string as current_trace->name.
2222 mutex_lock(&trace_types_lock
);
2223 if (unlikely(tr
->current_trace
&& iter
->trace
->name
!= tr
->current_trace
->name
))
2224 *iter
->trace
= *tr
->current_trace
;
2225 mutex_unlock(&trace_types_lock
);
2227 #ifdef CONFIG_TRACER_MAX_TRACE
2228 if (iter
->snapshot
&& iter
->trace
->use_max_tr
)
2229 return ERR_PTR(-EBUSY
);
2232 if (!iter
->snapshot
)
2233 atomic_inc(&trace_record_cmdline_disabled
);
2235 if (*pos
!= iter
->pos
) {
2240 if (cpu_file
== RING_BUFFER_ALL_CPUS
) {
2241 for_each_tracing_cpu(cpu
)
2242 tracing_iter_reset(iter
, cpu
);
2244 tracing_iter_reset(iter
, cpu_file
);
2247 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
2252 * If we overflowed the seq_file before, then we want
2253 * to just reuse the trace_seq buffer again.
2259 p
= s_next(m
, p
, &l
);
2263 trace_event_read_lock();
2264 trace_access_lock(cpu_file
);
2268 static void s_stop(struct seq_file
*m
, void *p
)
2270 struct trace_iterator
*iter
= m
->private;
2272 #ifdef CONFIG_TRACER_MAX_TRACE
2273 if (iter
->snapshot
&& iter
->trace
->use_max_tr
)
2277 if (!iter
->snapshot
)
2278 atomic_dec(&trace_record_cmdline_disabled
);
2280 trace_access_unlock(iter
->cpu_file
);
2281 trace_event_read_unlock();
2285 get_total_entries(struct trace_buffer
*buf
,
2286 unsigned long *total
, unsigned long *entries
)
2288 unsigned long count
;
2294 for_each_tracing_cpu(cpu
) {
2295 count
= ring_buffer_entries_cpu(buf
->buffer
, cpu
);
2297 * If this buffer has skipped entries, then we hold all
2298 * entries for the trace and we need to ignore the
2299 * ones before the time stamp.
2301 if (per_cpu_ptr(buf
->data
, cpu
)->skipped_entries
) {
2302 count
-= per_cpu_ptr(buf
->data
, cpu
)->skipped_entries
;
2303 /* total is the same as the entries */
2307 ring_buffer_overrun_cpu(buf
->buffer
, cpu
);
2312 static void print_lat_help_header(struct seq_file
*m
)
2314 seq_puts(m
, "# _------=> CPU# \n");
2315 seq_puts(m
, "# / _-----=> irqs-off \n");
2316 seq_puts(m
, "# | / _----=> need-resched \n");
2317 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
2318 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
2319 seq_puts(m
, "# |||| / delay \n");
2320 seq_puts(m
, "# cmd pid ||||| time | caller \n");
2321 seq_puts(m
, "# \\ / ||||| \\ | / \n");
2324 static void print_event_info(struct trace_buffer
*buf
, struct seq_file
*m
)
2326 unsigned long total
;
2327 unsigned long entries
;
2329 get_total_entries(buf
, &total
, &entries
);
2330 seq_printf(m
, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
2331 entries
, total
, num_online_cpus());
2335 static void print_func_help_header(struct trace_buffer
*buf
, struct seq_file
*m
)
2337 print_event_info(buf
, m
);
2338 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
2339 seq_puts(m
, "# | | | | |\n");
2342 static void print_func_help_header_irq(struct trace_buffer
*buf
, struct seq_file
*m
)
2344 print_event_info(buf
, m
);
2345 seq_puts(m
, "# _-----=> irqs-off\n");
2346 seq_puts(m
, "# / _----=> need-resched\n");
2347 seq_puts(m
, "# | / _---=> hardirq/softirq\n");
2348 seq_puts(m
, "# || / _--=> preempt-depth\n");
2349 seq_puts(m
, "# ||| / delay\n");
2350 seq_puts(m
, "# TASK-PID CPU# |||| TIMESTAMP FUNCTION\n");
2351 seq_puts(m
, "# | | | |||| | |\n");
2355 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
2357 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
2358 struct trace_buffer
*buf
= iter
->trace_buffer
;
2359 struct trace_array_cpu
*data
= per_cpu_ptr(buf
->data
, buf
->cpu
);
2360 struct tracer
*type
= iter
->trace
;
2361 unsigned long entries
;
2362 unsigned long total
;
2363 const char *name
= "preemption";
2367 get_total_entries(buf
, &total
, &entries
);
2369 seq_printf(m
, "# %s latency trace v1.1.5 on %s\n",
2371 seq_puts(m
, "# -----------------------------------"
2372 "---------------------------------\n");
2373 seq_printf(m
, "# latency: %lu us, #%lu/%lu, CPU#%d |"
2374 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
2375 nsecs_to_usecs(data
->saved_latency
),
2379 #if defined(CONFIG_PREEMPT_NONE)
2381 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
2383 #elif defined(CONFIG_PREEMPT)
2388 /* These are reserved for later use */
2391 seq_printf(m
, " #P:%d)\n", num_online_cpus());
2395 seq_puts(m
, "# -----------------\n");
2396 seq_printf(m
, "# | task: %.16s-%d "
2397 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
2398 data
->comm
, data
->pid
,
2399 from_kuid_munged(seq_user_ns(m
), data
->uid
), data
->nice
,
2400 data
->policy
, data
->rt_priority
);
2401 seq_puts(m
, "# -----------------\n");
2403 if (data
->critical_start
) {
2404 seq_puts(m
, "# => started at: ");
2405 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
2406 trace_print_seq(m
, &iter
->seq
);
2407 seq_puts(m
, "\n# => ended at: ");
2408 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
2409 trace_print_seq(m
, &iter
->seq
);
2410 seq_puts(m
, "\n#\n");
2416 static void test_cpu_buff_start(struct trace_iterator
*iter
)
2418 struct trace_seq
*s
= &iter
->seq
;
2420 if (!(trace_flags
& TRACE_ITER_ANNOTATE
))
2423 if (!(iter
->iter_flags
& TRACE_FILE_ANNOTATE
))
2426 if (cpumask_test_cpu(iter
->cpu
, iter
->started
))
2429 if (per_cpu_ptr(iter
->trace_buffer
->data
, iter
->cpu
)->skipped_entries
)
2432 cpumask_set_cpu(iter
->cpu
, iter
->started
);
2434 /* Don't print started cpu buffer for the first entry of the trace */
2436 trace_seq_printf(s
, "##### CPU %u buffer started ####\n",
2440 static enum print_line_t
print_trace_fmt(struct trace_iterator
*iter
)
2442 struct trace_seq
*s
= &iter
->seq
;
2443 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
2444 struct trace_entry
*entry
;
2445 struct trace_event
*event
;
2449 test_cpu_buff_start(iter
);
2451 event
= ftrace_find_event(entry
->type
);
2453 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2454 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
2455 if (!trace_print_lat_context(iter
))
2458 if (!trace_print_context(iter
))
2464 return event
->funcs
->trace(iter
, sym_flags
, event
);
2466 if (!trace_seq_printf(s
, "Unknown type %d\n", entry
->type
))
2469 return TRACE_TYPE_HANDLED
;
2471 return TRACE_TYPE_PARTIAL_LINE
;
2474 static enum print_line_t
print_raw_fmt(struct trace_iterator
*iter
)
2476 struct trace_seq
*s
= &iter
->seq
;
2477 struct trace_entry
*entry
;
2478 struct trace_event
*event
;
2482 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2483 if (!trace_seq_printf(s
, "%d %d %llu ",
2484 entry
->pid
, iter
->cpu
, iter
->ts
))
2488 event
= ftrace_find_event(entry
->type
);
2490 return event
->funcs
->raw(iter
, 0, event
);
2492 if (!trace_seq_printf(s
, "%d ?\n", entry
->type
))
2495 return TRACE_TYPE_HANDLED
;
2497 return TRACE_TYPE_PARTIAL_LINE
;
2500 static enum print_line_t
print_hex_fmt(struct trace_iterator
*iter
)
2502 struct trace_seq
*s
= &iter
->seq
;
2503 unsigned char newline
= '\n';
2504 struct trace_entry
*entry
;
2505 struct trace_event
*event
;
2509 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2510 SEQ_PUT_HEX_FIELD_RET(s
, entry
->pid
);
2511 SEQ_PUT_HEX_FIELD_RET(s
, iter
->cpu
);
2512 SEQ_PUT_HEX_FIELD_RET(s
, iter
->ts
);
2515 event
= ftrace_find_event(entry
->type
);
2517 enum print_line_t ret
= event
->funcs
->hex(iter
, 0, event
);
2518 if (ret
!= TRACE_TYPE_HANDLED
)
2522 SEQ_PUT_FIELD_RET(s
, newline
);
2524 return TRACE_TYPE_HANDLED
;
2527 static enum print_line_t
print_bin_fmt(struct trace_iterator
*iter
)
2529 struct trace_seq
*s
= &iter
->seq
;
2530 struct trace_entry
*entry
;
2531 struct trace_event
*event
;
2535 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
2536 SEQ_PUT_FIELD_RET(s
, entry
->pid
);
2537 SEQ_PUT_FIELD_RET(s
, iter
->cpu
);
2538 SEQ_PUT_FIELD_RET(s
, iter
->ts
);
2541 event
= ftrace_find_event(entry
->type
);
2542 return event
? event
->funcs
->binary(iter
, 0, event
) :
2546 int trace_empty(struct trace_iterator
*iter
)
2548 struct ring_buffer_iter
*buf_iter
;
2551 /* If we are looking at one CPU buffer, only check that one */
2552 if (iter
->cpu_file
!= RING_BUFFER_ALL_CPUS
) {
2553 cpu
= iter
->cpu_file
;
2554 buf_iter
= trace_buffer_iter(iter
, cpu
);
2556 if (!ring_buffer_iter_empty(buf_iter
))
2559 if (!ring_buffer_empty_cpu(iter
->trace_buffer
->buffer
, cpu
))
2565 for_each_tracing_cpu(cpu
) {
2566 buf_iter
= trace_buffer_iter(iter
, cpu
);
2568 if (!ring_buffer_iter_empty(buf_iter
))
2571 if (!ring_buffer_empty_cpu(iter
->trace_buffer
->buffer
, cpu
))
2579 /* Called with trace_event_read_lock() held. */
2580 enum print_line_t
print_trace_line(struct trace_iterator
*iter
)
2582 enum print_line_t ret
;
2584 if (iter
->lost_events
&&
2585 !trace_seq_printf(&iter
->seq
, "CPU:%d [LOST %lu EVENTS]\n",
2586 iter
->cpu
, iter
->lost_events
))
2587 return TRACE_TYPE_PARTIAL_LINE
;
2589 if (iter
->trace
&& iter
->trace
->print_line
) {
2590 ret
= iter
->trace
->print_line(iter
);
2591 if (ret
!= TRACE_TYPE_UNHANDLED
)
2595 if (iter
->ent
->type
== TRACE_BPUTS
&&
2596 trace_flags
& TRACE_ITER_PRINTK
&&
2597 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2598 return trace_print_bputs_msg_only(iter
);
2600 if (iter
->ent
->type
== TRACE_BPRINT
&&
2601 trace_flags
& TRACE_ITER_PRINTK
&&
2602 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2603 return trace_print_bprintk_msg_only(iter
);
2605 if (iter
->ent
->type
== TRACE_PRINT
&&
2606 trace_flags
& TRACE_ITER_PRINTK
&&
2607 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
2608 return trace_print_printk_msg_only(iter
);
2610 if (trace_flags
& TRACE_ITER_BIN
)
2611 return print_bin_fmt(iter
);
2613 if (trace_flags
& TRACE_ITER_HEX
)
2614 return print_hex_fmt(iter
);
2616 if (trace_flags
& TRACE_ITER_RAW
)
2617 return print_raw_fmt(iter
);
2619 return print_trace_fmt(iter
);
2622 void trace_latency_header(struct seq_file
*m
)
2624 struct trace_iterator
*iter
= m
->private;
2626 /* print nothing if the buffers are empty */
2627 if (trace_empty(iter
))
2630 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
)
2631 print_trace_header(m
, iter
);
2633 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2634 print_lat_help_header(m
);
2637 void trace_default_header(struct seq_file
*m
)
2639 struct trace_iterator
*iter
= m
->private;
2641 if (!(trace_flags
& TRACE_ITER_CONTEXT_INFO
))
2644 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
2645 /* print nothing if the buffers are empty */
2646 if (trace_empty(iter
))
2648 print_trace_header(m
, iter
);
2649 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
2650 print_lat_help_header(m
);
2652 if (!(trace_flags
& TRACE_ITER_VERBOSE
)) {
2653 if (trace_flags
& TRACE_ITER_IRQ_INFO
)
2654 print_func_help_header_irq(iter
->trace_buffer
, m
);
2656 print_func_help_header(iter
->trace_buffer
, m
);
2661 static void test_ftrace_alive(struct seq_file
*m
)
2663 if (!ftrace_is_dead())
2665 seq_printf(m
, "# WARNING: FUNCTION TRACING IS CORRUPTED\n");
2666 seq_printf(m
, "# MAY BE MISSING FUNCTION EVENTS\n");
2669 #ifdef CONFIG_TRACER_MAX_TRACE
2670 static void show_snapshot_main_help(struct seq_file
*m
)
2672 seq_printf(m
, "# echo 0 > snapshot : Clears and frees snapshot buffer\n");
2673 seq_printf(m
, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
2674 seq_printf(m
, "# Takes a snapshot of the main buffer.\n");
2675 seq_printf(m
, "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate)\n");
2676 seq_printf(m
, "# (Doesn't have to be '2' works with any number that\n");
2677 seq_printf(m
, "# is not a '0' or '1')\n");
2680 static void show_snapshot_percpu_help(struct seq_file
*m
)
2682 seq_printf(m
, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
2683 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
2684 seq_printf(m
, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
2685 seq_printf(m
, "# Takes a snapshot of the main buffer for this cpu.\n");
2687 seq_printf(m
, "# echo 1 > snapshot : Not supported with this kernel.\n");
2688 seq_printf(m
, "# Must use main snapshot file to allocate.\n");
2690 seq_printf(m
, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n");
2691 seq_printf(m
, "# (Doesn't have to be '2' works with any number that\n");
2692 seq_printf(m
, "# is not a '0' or '1')\n");
2695 static void print_snapshot_help(struct seq_file
*m
, struct trace_iterator
*iter
)
2697 if (iter
->tr
->allocated_snapshot
)
2698 seq_printf(m
, "#\n# * Snapshot is allocated *\n#\n");
2700 seq_printf(m
, "#\n# * Snapshot is freed *\n#\n");
2702 seq_printf(m
, "# Snapshot commands:\n");
2703 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
)
2704 show_snapshot_main_help(m
);
2706 show_snapshot_percpu_help(m
);
2709 /* Should never be called */
2710 static inline void print_snapshot_help(struct seq_file
*m
, struct trace_iterator
*iter
) { }
2713 static int s_show(struct seq_file
*m
, void *v
)
2715 struct trace_iterator
*iter
= v
;
2718 if (iter
->ent
== NULL
) {
2720 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
2722 test_ftrace_alive(m
);
2724 if (iter
->snapshot
&& trace_empty(iter
))
2725 print_snapshot_help(m
, iter
);
2726 else if (iter
->trace
&& iter
->trace
->print_header
)
2727 iter
->trace
->print_header(m
);
2729 trace_default_header(m
);
2731 } else if (iter
->leftover
) {
2733 * If we filled the seq_file buffer earlier, we
2734 * want to just show it now.
2736 ret
= trace_print_seq(m
, &iter
->seq
);
2738 /* ret should this time be zero, but you never know */
2739 iter
->leftover
= ret
;
2742 print_trace_line(iter
);
2743 ret
= trace_print_seq(m
, &iter
->seq
);
2745 * If we overflow the seq_file buffer, then it will
2746 * ask us for this data again at start up.
2748 * ret is 0 if seq_file write succeeded.
2751 iter
->leftover
= ret
;
2757 static const struct seq_operations tracer_seq_ops
= {
2764 static struct trace_iterator
*
2765 __tracing_open(struct inode
*inode
, struct file
*file
, bool snapshot
)
2767 struct trace_cpu
*tc
= inode
->i_private
;
2768 struct trace_array
*tr
= tc
->tr
;
2769 struct trace_iterator
*iter
;
2772 if (tracing_disabled
)
2773 return ERR_PTR(-ENODEV
);
2775 iter
= __seq_open_private(file
, &tracer_seq_ops
, sizeof(*iter
));
2777 return ERR_PTR(-ENOMEM
);
2779 iter
->buffer_iter
= kzalloc(sizeof(*iter
->buffer_iter
) * num_possible_cpus(),
2781 if (!iter
->buffer_iter
)
2785 * We make a copy of the current tracer to avoid concurrent
2786 * changes on it while we are reading.
2788 mutex_lock(&trace_types_lock
);
2789 iter
->trace
= kzalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
2793 *iter
->trace
= *tr
->current_trace
;
2795 if (!zalloc_cpumask_var(&iter
->started
, GFP_KERNEL
))
2800 #ifdef CONFIG_TRACER_MAX_TRACE
2801 /* Currently only the top directory has a snapshot */
2802 if (tr
->current_trace
->print_max
|| snapshot
)
2803 iter
->trace_buffer
= &tr
->max_buffer
;
2806 iter
->trace_buffer
= &tr
->trace_buffer
;
2807 iter
->snapshot
= snapshot
;
2809 mutex_init(&iter
->mutex
);
2810 iter
->cpu_file
= tc
->cpu
;
2812 /* Notify the tracer early; before we stop tracing. */
2813 if (iter
->trace
&& iter
->trace
->open
)
2814 iter
->trace
->open(iter
);
2816 /* Annotate start of buffers if we had overruns */
2817 if (ring_buffer_overruns(iter
->trace_buffer
->buffer
))
2818 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
2820 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
2821 if (trace_clocks
[trace_clock_id
].in_ns
)
2822 iter
->iter_flags
|= TRACE_FILE_TIME_IN_NS
;
2824 /* stop the trace while dumping if we are not opening "snapshot" */
2825 if (!iter
->snapshot
)
2826 tracing_stop_tr(tr
);
2828 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
) {
2829 for_each_tracing_cpu(cpu
) {
2830 iter
->buffer_iter
[cpu
] =
2831 ring_buffer_read_prepare(iter
->trace_buffer
->buffer
, cpu
);
2833 ring_buffer_read_prepare_sync();
2834 for_each_tracing_cpu(cpu
) {
2835 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2836 tracing_iter_reset(iter
, cpu
);
2839 cpu
= iter
->cpu_file
;
2840 iter
->buffer_iter
[cpu
] =
2841 ring_buffer_read_prepare(iter
->trace_buffer
->buffer
, cpu
);
2842 ring_buffer_read_prepare_sync();
2843 ring_buffer_read_start(iter
->buffer_iter
[cpu
]);
2844 tracing_iter_reset(iter
, cpu
);
2849 mutex_unlock(&trace_types_lock
);
2854 mutex_unlock(&trace_types_lock
);
2856 kfree(iter
->buffer_iter
);
2858 seq_release_private(inode
, file
);
2859 return ERR_PTR(-ENOMEM
);
2862 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
2864 if (tracing_disabled
)
2867 filp
->private_data
= inode
->i_private
;
2871 static int tracing_release(struct inode
*inode
, struct file
*file
)
2873 struct seq_file
*m
= file
->private_data
;
2874 struct trace_iterator
*iter
;
2875 struct trace_array
*tr
;
2878 if (!(file
->f_mode
& FMODE_READ
))
2884 mutex_lock(&trace_types_lock
);
2889 for_each_tracing_cpu(cpu
) {
2890 if (iter
->buffer_iter
[cpu
])
2891 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
2894 if (iter
->trace
&& iter
->trace
->close
)
2895 iter
->trace
->close(iter
);
2897 if (!iter
->snapshot
)
2898 /* reenable tracing if it was previously enabled */
2899 tracing_start_tr(tr
);
2900 mutex_unlock(&trace_types_lock
);
2902 mutex_destroy(&iter
->mutex
);
2903 free_cpumask_var(iter
->started
);
2905 kfree(iter
->buffer_iter
);
2906 seq_release_private(inode
, file
);
2910 static int tracing_open(struct inode
*inode
, struct file
*file
)
2912 struct trace_iterator
*iter
;
2915 /* If this file was open for write, then erase contents */
2916 if ((file
->f_mode
& FMODE_WRITE
) &&
2917 (file
->f_flags
& O_TRUNC
)) {
2918 struct trace_cpu
*tc
= inode
->i_private
;
2919 struct trace_array
*tr
= tc
->tr
;
2921 if (tc
->cpu
== RING_BUFFER_ALL_CPUS
)
2922 tracing_reset_online_cpus(&tr
->trace_buffer
);
2924 tracing_reset(&tr
->trace_buffer
, tc
->cpu
);
2927 if (file
->f_mode
& FMODE_READ
) {
2928 iter
= __tracing_open(inode
, file
, false);
2930 ret
= PTR_ERR(iter
);
2931 else if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
2932 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
2938 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
2940 struct tracer
*t
= v
;
2950 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
2955 mutex_lock(&trace_types_lock
);
2956 for (t
= trace_types
; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
2962 static void t_stop(struct seq_file
*m
, void *p
)
2964 mutex_unlock(&trace_types_lock
);
2967 static int t_show(struct seq_file
*m
, void *v
)
2969 struct tracer
*t
= v
;
2974 seq_printf(m
, "%s", t
->name
);
2983 static const struct seq_operations show_traces_seq_ops
= {
2990 static int show_traces_open(struct inode
*inode
, struct file
*file
)
2992 if (tracing_disabled
)
2995 return seq_open(file
, &show_traces_seq_ops
);
2999 tracing_write_stub(struct file
*filp
, const char __user
*ubuf
,
3000 size_t count
, loff_t
*ppos
)
3005 static loff_t
tracing_seek(struct file
*file
, loff_t offset
, int origin
)
3007 if (file
->f_mode
& FMODE_READ
)
3008 return seq_lseek(file
, offset
, origin
);
3013 static const struct file_operations tracing_fops
= {
3014 .open
= tracing_open
,
3016 .write
= tracing_write_stub
,
3017 .llseek
= tracing_seek
,
3018 .release
= tracing_release
,
3021 static const struct file_operations show_traces_fops
= {
3022 .open
= show_traces_open
,
3024 .release
= seq_release
,
3025 .llseek
= seq_lseek
,
3029 * Only trace on a CPU if the bitmask is set:
3031 static cpumask_var_t tracing_cpumask
;
3034 * The tracer itself will not take this lock, but still we want
3035 * to provide a consistent cpumask to user-space:
3037 static DEFINE_MUTEX(tracing_cpumask_update_lock
);
3040 * Temporary storage for the character representation of the
3041 * CPU bitmask (and one more byte for the newline):
3043 static char mask_str
[NR_CPUS
+ 1];
3046 tracing_cpumask_read(struct file
*filp
, char __user
*ubuf
,
3047 size_t count
, loff_t
*ppos
)
3051 mutex_lock(&tracing_cpumask_update_lock
);
3053 len
= cpumask_scnprintf(mask_str
, count
, tracing_cpumask
);
3054 if (count
- len
< 2) {
3058 len
+= sprintf(mask_str
+ len
, "\n");
3059 count
= simple_read_from_buffer(ubuf
, count
, ppos
, mask_str
, NR_CPUS
+1);
3062 mutex_unlock(&tracing_cpumask_update_lock
);
3068 tracing_cpumask_write(struct file
*filp
, const char __user
*ubuf
,
3069 size_t count
, loff_t
*ppos
)
3071 struct trace_array
*tr
= filp
->private_data
;
3072 cpumask_var_t tracing_cpumask_new
;
3075 if (!alloc_cpumask_var(&tracing_cpumask_new
, GFP_KERNEL
))
3078 err
= cpumask_parse_user(ubuf
, count
, tracing_cpumask_new
);
3082 mutex_lock(&tracing_cpumask_update_lock
);
3084 local_irq_disable();
3085 arch_spin_lock(&ftrace_max_lock
);
3086 for_each_tracing_cpu(cpu
) {
3088 * Increase/decrease the disabled counter if we are
3089 * about to flip a bit in the cpumask:
3091 if (cpumask_test_cpu(cpu
, tracing_cpumask
) &&
3092 !cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
3093 atomic_inc(&per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->disabled
);
3094 ring_buffer_record_disable_cpu(tr
->trace_buffer
.buffer
, cpu
);
3096 if (!cpumask_test_cpu(cpu
, tracing_cpumask
) &&
3097 cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
3098 atomic_dec(&per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->disabled
);
3099 ring_buffer_record_enable_cpu(tr
->trace_buffer
.buffer
, cpu
);
3102 arch_spin_unlock(&ftrace_max_lock
);
3105 cpumask_copy(tracing_cpumask
, tracing_cpumask_new
);
3107 mutex_unlock(&tracing_cpumask_update_lock
);
3108 free_cpumask_var(tracing_cpumask_new
);
3113 free_cpumask_var(tracing_cpumask_new
);
3118 static const struct file_operations tracing_cpumask_fops
= {
3119 .open
= tracing_open_generic
,
3120 .read
= tracing_cpumask_read
,
3121 .write
= tracing_cpumask_write
,
3122 .llseek
= generic_file_llseek
,
3125 static int tracing_trace_options_show(struct seq_file
*m
, void *v
)
3127 struct tracer_opt
*trace_opts
;
3128 struct trace_array
*tr
= m
->private;
3132 mutex_lock(&trace_types_lock
);
3133 tracer_flags
= tr
->current_trace
->flags
->val
;
3134 trace_opts
= tr
->current_trace
->flags
->opts
;
3136 for (i
= 0; trace_options
[i
]; i
++) {
3137 if (trace_flags
& (1 << i
))
3138 seq_printf(m
, "%s\n", trace_options
[i
]);
3140 seq_printf(m
, "no%s\n", trace_options
[i
]);
3143 for (i
= 0; trace_opts
[i
].name
; i
++) {
3144 if (tracer_flags
& trace_opts
[i
].bit
)
3145 seq_printf(m
, "%s\n", trace_opts
[i
].name
);
3147 seq_printf(m
, "no%s\n", trace_opts
[i
].name
);
3149 mutex_unlock(&trace_types_lock
);
3154 static int __set_tracer_option(struct tracer
*trace
,
3155 struct tracer_flags
*tracer_flags
,
3156 struct tracer_opt
*opts
, int neg
)
3160 ret
= trace
->set_flag(tracer_flags
->val
, opts
->bit
, !neg
);
3165 tracer_flags
->val
&= ~opts
->bit
;
3167 tracer_flags
->val
|= opts
->bit
;
3171 /* Try to assign a tracer specific option */
3172 static int set_tracer_option(struct tracer
*trace
, char *cmp
, int neg
)
3174 struct tracer_flags
*tracer_flags
= trace
->flags
;
3175 struct tracer_opt
*opts
= NULL
;
3178 for (i
= 0; tracer_flags
->opts
[i
].name
; i
++) {
3179 opts
= &tracer_flags
->opts
[i
];
3181 if (strcmp(cmp
, opts
->name
) == 0)
3182 return __set_tracer_option(trace
, trace
->flags
,
3189 /* Some tracers require overwrite to stay enabled */
3190 int trace_keep_overwrite(struct tracer
*tracer
, u32 mask
, int set
)
3192 if (tracer
->enabled
&& (mask
& TRACE_ITER_OVERWRITE
) && !set
)
3198 int set_tracer_flag(struct trace_array
*tr
, unsigned int mask
, int enabled
)
3200 /* do nothing if flag is already set */
3201 if (!!(trace_flags
& mask
) == !!enabled
)
3204 /* Give the tracer a chance to approve the change */
3205 if (tr
->current_trace
->flag_changed
)
3206 if (tr
->current_trace
->flag_changed(tr
->current_trace
, mask
, !!enabled
))
3210 trace_flags
|= mask
;
3212 trace_flags
&= ~mask
;
3214 if (mask
== TRACE_ITER_RECORD_CMD
)
3215 trace_event_enable_cmd_record(enabled
);
3217 if (mask
== TRACE_ITER_OVERWRITE
) {
3218 ring_buffer_change_overwrite(tr
->trace_buffer
.buffer
, enabled
);
3219 #ifdef CONFIG_TRACER_MAX_TRACE
3220 ring_buffer_change_overwrite(tr
->max_buffer
.buffer
, enabled
);
3224 if (mask
== TRACE_ITER_PRINTK
)
3225 trace_printk_start_stop_comm(enabled
);
3230 static int trace_set_options(struct trace_array
*tr
, char *option
)
3237 cmp
= strstrip(option
);
3239 if (strncmp(cmp
, "no", 2) == 0) {
3244 mutex_lock(&trace_types_lock
);
3246 for (i
= 0; trace_options
[i
]; i
++) {
3247 if (strcmp(cmp
, trace_options
[i
]) == 0) {
3248 ret
= set_tracer_flag(tr
, 1 << i
, !neg
);
3253 /* If no option could be set, test the specific tracer options */
3254 if (!trace_options
[i
])
3255 ret
= set_tracer_option(tr
->current_trace
, cmp
, neg
);
3257 mutex_unlock(&trace_types_lock
);
3263 tracing_trace_options_write(struct file
*filp
, const char __user
*ubuf
,
3264 size_t cnt
, loff_t
*ppos
)
3266 struct seq_file
*m
= filp
->private_data
;
3267 struct trace_array
*tr
= m
->private;
3271 if (cnt
>= sizeof(buf
))
3274 if (copy_from_user(&buf
, ubuf
, cnt
))
3279 ret
= trace_set_options(tr
, buf
);
3288 static int tracing_trace_options_open(struct inode
*inode
, struct file
*file
)
3290 if (tracing_disabled
)
3293 return single_open(file
, tracing_trace_options_show
, inode
->i_private
);
3296 static const struct file_operations tracing_iter_fops
= {
3297 .open
= tracing_trace_options_open
,
3299 .llseek
= seq_lseek
,
3300 .release
= single_release
,
3301 .write
= tracing_trace_options_write
,
3304 static const char readme_msg
[] =
3305 "tracing mini-HOWTO:\n\n"
3306 "# echo 0 > tracing_on : quick way to disable tracing\n"
3307 "# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
3308 " Important files:\n"
3309 " trace\t\t\t- The static contents of the buffer\n"
3310 "\t\t\t To clear the buffer write into this file: echo > trace\n"
3311 " trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
3312 " current_tracer\t- function and latency tracers\n"
3313 " available_tracers\t- list of configured tracers for current_tracer\n"
3314 " buffer_size_kb\t- view and modify size of per cpu buffer\n"
3315 " buffer_total_size_kb - view total size of all cpu buffers\n\n"
3316 " trace_clock\t\t-change the clock used to order events\n"
3317 " local: Per cpu clock but may not be synced across CPUs\n"
3318 " global: Synced across CPUs but slows tracing down.\n"
3319 " counter: Not a clock, but just an increment\n"
3320 " uptime: Jiffy counter from time of boot\n"
3321 " perf: Same clock that perf events use\n"
3322 #ifdef CONFIG_X86_64
3323 " x86-tsc: TSC cycle counter\n"
3325 "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
3326 " tracing_cpumask\t- Limit which CPUs to trace\n"
3327 " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
3328 "\t\t\t Remove sub-buffer with rmdir\n"
3329 " trace_options\t\t- Set format or modify how tracing happens\n"
3330 "\t\t\t Disable an option by adding a suffix 'no' to the option name\n"
3331 #ifdef CONFIG_DYNAMIC_FTRACE
3332 "\n available_filter_functions - list of functions that can be filtered on\n"
3333 " set_ftrace_filter\t- echo function name in here to only trace these functions\n"
3334 " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3335 " modules: Can select a group via module\n"
3336 " Format: :mod:<module-name>\n"
3337 " example: echo :mod:ext3 > set_ftrace_filter\n"
3338 " triggers: a command to perform when function is hit\n"
3339 " Format: <function>:<trigger>[:count]\n"
3340 " trigger: traceon, traceoff\n"
3341 " enable_event:<system>:<event>\n"
3342 " disable_event:<system>:<event>\n"
3343 #ifdef CONFIG_STACKTRACE
3346 #ifdef CONFIG_TRACER_SNAPSHOT
3349 " example: echo do_fault:traceoff > set_ftrace_filter\n"
3350 " echo do_trap:traceoff:3 > set_ftrace_filter\n"
3351 " The first one will disable tracing every time do_fault is hit\n"
3352 " The second will disable tracing at most 3 times when do_trap is hit\n"
3353 " The first time do trap is hit and it disables tracing, the counter\n"
3354 " will decrement to 2. If tracing is already disabled, the counter\n"
3355 " will not decrement. It only decrements when the trigger did work\n"
3356 " To remove trigger without count:\n"
3357 " echo '!<function>:<trigger> > set_ftrace_filter\n"
3358 " To remove trigger with a count:\n"
3359 " echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
3360 " set_ftrace_notrace\t- echo function name in here to never trace.\n"
3361 " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3362 " modules: Can select a group via module command :mod:\n"
3363 " Does not accept triggers\n"
3364 #endif /* CONFIG_DYNAMIC_FTRACE */
3365 #ifdef CONFIG_FUNCTION_TRACER
3366 " set_ftrace_pid\t- Write pid(s) to only function trace those pids (function)\n"
3368 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3369 " set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
3370 " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
3372 #ifdef CONFIG_TRACER_SNAPSHOT
3373 "\n snapshot\t\t- Like 'trace' but shows the content of the static snapshot buffer\n"
3374 "\t\t\t Read the contents for more information\n"
3376 #ifdef CONFIG_STACKTRACE
3377 " stack_trace\t\t- Shows the max stack trace when active\n"
3378 " stack_max_size\t- Shows current max stack size that was traced\n"
3379 "\t\t\t Write into this file to reset the max size (trigger a new trace)\n"
3380 #ifdef CONFIG_DYNAMIC_FTRACE
3381 " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace traces\n"
3383 #endif /* CONFIG_STACKTRACE */
3387 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
3388 size_t cnt
, loff_t
*ppos
)
3390 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
3391 readme_msg
, strlen(readme_msg
));
3394 static const struct file_operations tracing_readme_fops
= {
3395 .open
= tracing_open_generic
,
3396 .read
= tracing_readme_read
,
3397 .llseek
= generic_file_llseek
,
3401 tracing_saved_cmdlines_read(struct file
*file
, char __user
*ubuf
,
3402 size_t cnt
, loff_t
*ppos
)
3411 file_buf
= kmalloc(SAVED_CMDLINES
*(16+TASK_COMM_LEN
), GFP_KERNEL
);
3415 buf_comm
= kmalloc(TASK_COMM_LEN
, GFP_KERNEL
);
3423 for (i
= 0; i
< SAVED_CMDLINES
; i
++) {
3426 pid
= map_cmdline_to_pid
[i
];
3427 if (pid
== -1 || pid
== NO_CMDLINE_MAP
)
3430 trace_find_cmdline(pid
, buf_comm
);
3431 r
= sprintf(buf
, "%d %s\n", pid
, buf_comm
);
3436 len
= simple_read_from_buffer(ubuf
, cnt
, ppos
,
3445 static const struct file_operations tracing_saved_cmdlines_fops
= {
3446 .open
= tracing_open_generic
,
3447 .read
= tracing_saved_cmdlines_read
,
3448 .llseek
= generic_file_llseek
,
3452 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
3453 size_t cnt
, loff_t
*ppos
)
3455 struct trace_array
*tr
= filp
->private_data
;
3456 char buf
[MAX_TRACER_SIZE
+2];
3459 mutex_lock(&trace_types_lock
);
3460 r
= sprintf(buf
, "%s\n", tr
->current_trace
->name
);
3461 mutex_unlock(&trace_types_lock
);
3463 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3466 int tracer_init(struct tracer
*t
, struct trace_array
*tr
)
3468 tracing_reset_online_cpus(&tr
->trace_buffer
);
3472 static void set_buffer_entries(struct trace_buffer
*buf
, unsigned long val
)
3476 for_each_tracing_cpu(cpu
)
3477 per_cpu_ptr(buf
->data
, cpu
)->entries
= val
;
3480 #ifdef CONFIG_TRACER_MAX_TRACE
3481 /* resize @tr's buffer to the size of @size_tr's entries */
3482 static int resize_buffer_duplicate_size(struct trace_buffer
*trace_buf
,
3483 struct trace_buffer
*size_buf
, int cpu_id
)
3487 if (cpu_id
== RING_BUFFER_ALL_CPUS
) {
3488 for_each_tracing_cpu(cpu
) {
3489 ret
= ring_buffer_resize(trace_buf
->buffer
,
3490 per_cpu_ptr(size_buf
->data
, cpu
)->entries
, cpu
);
3493 per_cpu_ptr(trace_buf
->data
, cpu
)->entries
=
3494 per_cpu_ptr(size_buf
->data
, cpu
)->entries
;
3497 ret
= ring_buffer_resize(trace_buf
->buffer
,
3498 per_cpu_ptr(size_buf
->data
, cpu_id
)->entries
, cpu_id
);
3500 per_cpu_ptr(trace_buf
->data
, cpu_id
)->entries
=
3501 per_cpu_ptr(size_buf
->data
, cpu_id
)->entries
;
3506 #endif /* CONFIG_TRACER_MAX_TRACE */
3508 static int __tracing_resize_ring_buffer(struct trace_array
*tr
,
3509 unsigned long size
, int cpu
)
3514 * If kernel or user changes the size of the ring buffer
3515 * we use the size that was given, and we can forget about
3516 * expanding it later.
3518 ring_buffer_expanded
= true;
3520 /* May be called before buffers are initialized */
3521 if (!tr
->trace_buffer
.buffer
)
3524 ret
= ring_buffer_resize(tr
->trace_buffer
.buffer
, size
, cpu
);
3528 #ifdef CONFIG_TRACER_MAX_TRACE
3529 if (!(tr
->flags
& TRACE_ARRAY_FL_GLOBAL
) ||
3530 !tr
->current_trace
->use_max_tr
)
3533 ret
= ring_buffer_resize(tr
->max_buffer
.buffer
, size
, cpu
);
3535 int r
= resize_buffer_duplicate_size(&tr
->trace_buffer
,
3536 &tr
->trace_buffer
, cpu
);
3539 * AARGH! We are left with different
3540 * size max buffer!!!!
3541 * The max buffer is our "snapshot" buffer.
3542 * When a tracer needs a snapshot (one of the
3543 * latency tracers), it swaps the max buffer
3544 * with the saved snap shot. We succeeded to
3545 * update the size of the main buffer, but failed to
3546 * update the size of the max buffer. But when we tried
3547 * to reset the main buffer to the original size, we
3548 * failed there too. This is very unlikely to
3549 * happen, but if it does, warn and kill all
3553 tracing_disabled
= 1;
3558 if (cpu
== RING_BUFFER_ALL_CPUS
)
3559 set_buffer_entries(&tr
->max_buffer
, size
);
3561 per_cpu_ptr(tr
->max_buffer
.data
, cpu
)->entries
= size
;
3564 #endif /* CONFIG_TRACER_MAX_TRACE */
3566 if (cpu
== RING_BUFFER_ALL_CPUS
)
3567 set_buffer_entries(&tr
->trace_buffer
, size
);
3569 per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
= size
;
3574 static ssize_t
tracing_resize_ring_buffer(struct trace_array
*tr
,
3575 unsigned long size
, int cpu_id
)
3579 mutex_lock(&trace_types_lock
);
3581 if (cpu_id
!= RING_BUFFER_ALL_CPUS
) {
3582 /* make sure, this cpu is enabled in the mask */
3583 if (!cpumask_test_cpu(cpu_id
, tracing_buffer_mask
)) {
3589 ret
= __tracing_resize_ring_buffer(tr
, size
, cpu_id
);
3594 mutex_unlock(&trace_types_lock
);
3601 * tracing_update_buffers - used by tracing facility to expand ring buffers
3603 * To save on memory when the tracing is never used on a system with it
3604 * configured in. The ring buffers are set to a minimum size. But once
3605 * a user starts to use the tracing facility, then they need to grow
3606 * to their default size.
3608 * This function is to be called when a tracer is about to be used.
3610 int tracing_update_buffers(void)
3614 mutex_lock(&trace_types_lock
);
3615 if (!ring_buffer_expanded
)
3616 ret
= __tracing_resize_ring_buffer(&global_trace
, trace_buf_size
,
3617 RING_BUFFER_ALL_CPUS
);
3618 mutex_unlock(&trace_types_lock
);
3623 struct trace_option_dentry
;
3625 static struct trace_option_dentry
*
3626 create_trace_option_files(struct trace_array
*tr
, struct tracer
*tracer
);
3629 destroy_trace_option_files(struct trace_option_dentry
*topts
);
3631 static int tracing_set_tracer(const char *buf
)
3633 static struct trace_option_dentry
*topts
;
3634 struct trace_array
*tr
= &global_trace
;
3636 #ifdef CONFIG_TRACER_MAX_TRACE
3641 mutex_lock(&trace_types_lock
);
3643 if (!ring_buffer_expanded
) {
3644 ret
= __tracing_resize_ring_buffer(tr
, trace_buf_size
,
3645 RING_BUFFER_ALL_CPUS
);
3651 for (t
= trace_types
; t
; t
= t
->next
) {
3652 if (strcmp(t
->name
, buf
) == 0)
3659 if (t
== tr
->current_trace
)
3662 trace_branch_disable();
3664 tr
->current_trace
->enabled
= false;
3666 if (tr
->current_trace
->reset
)
3667 tr
->current_trace
->reset(tr
);
3669 /* Current trace needs to be nop_trace before synchronize_sched */
3670 tr
->current_trace
= &nop_trace
;
3672 #ifdef CONFIG_TRACER_MAX_TRACE
3673 had_max_tr
= tr
->allocated_snapshot
;
3675 if (had_max_tr
&& !t
->use_max_tr
) {
3677 * We need to make sure that the update_max_tr sees that
3678 * current_trace changed to nop_trace to keep it from
3679 * swapping the buffers after we resize it.
3680 * The update_max_tr is called from interrupts disabled
3681 * so a synchronized_sched() is sufficient.
3683 synchronize_sched();
3687 destroy_trace_option_files(topts
);
3689 topts
= create_trace_option_files(tr
, t
);
3691 #ifdef CONFIG_TRACER_MAX_TRACE
3692 if (t
->use_max_tr
&& !had_max_tr
) {
3693 ret
= alloc_snapshot(tr
);
3700 ret
= tracer_init(t
, tr
);
3705 tr
->current_trace
= t
;
3706 tr
->current_trace
->enabled
= true;
3707 trace_branch_enable(tr
);
3709 mutex_unlock(&trace_types_lock
);
3715 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
3716 size_t cnt
, loff_t
*ppos
)
3718 char buf
[MAX_TRACER_SIZE
+1];
3725 if (cnt
> MAX_TRACER_SIZE
)
3726 cnt
= MAX_TRACER_SIZE
;
3728 if (copy_from_user(&buf
, ubuf
, cnt
))
3733 /* strip ending whitespace. */
3734 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
3737 err
= tracing_set_tracer(buf
);
3747 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
3748 size_t cnt
, loff_t
*ppos
)
3750 unsigned long *ptr
= filp
->private_data
;
3754 r
= snprintf(buf
, sizeof(buf
), "%ld\n",
3755 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
3756 if (r
> sizeof(buf
))
3758 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3762 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
3763 size_t cnt
, loff_t
*ppos
)
3765 unsigned long *ptr
= filp
->private_data
;
3769 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
3778 static int tracing_open_pipe(struct inode
*inode
, struct file
*filp
)
3780 struct trace_cpu
*tc
= inode
->i_private
;
3781 struct trace_array
*tr
= tc
->tr
;
3782 struct trace_iterator
*iter
;
3785 if (tracing_disabled
)
3788 mutex_lock(&trace_types_lock
);
3790 /* create a buffer to store the information to pass to userspace */
3791 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
3798 * We make a copy of the current tracer to avoid concurrent
3799 * changes on it while we are reading.
3801 iter
->trace
= kmalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
3806 *iter
->trace
= *tr
->current_trace
;
3808 if (!alloc_cpumask_var(&iter
->started
, GFP_KERNEL
)) {
3813 /* trace pipe does not show start of buffer */
3814 cpumask_setall(iter
->started
);
3816 if (trace_flags
& TRACE_ITER_LATENCY_FMT
)
3817 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
3819 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
3820 if (trace_clocks
[trace_clock_id
].in_ns
)
3821 iter
->iter_flags
|= TRACE_FILE_TIME_IN_NS
;
3823 iter
->cpu_file
= tc
->cpu
;
3825 iter
->trace_buffer
= &tc
->tr
->trace_buffer
;
3826 mutex_init(&iter
->mutex
);
3827 filp
->private_data
= iter
;
3829 if (iter
->trace
->pipe_open
)
3830 iter
->trace
->pipe_open(iter
);
3832 nonseekable_open(inode
, filp
);
3834 mutex_unlock(&trace_types_lock
);
3840 mutex_unlock(&trace_types_lock
);
3844 static int tracing_release_pipe(struct inode
*inode
, struct file
*file
)
3846 struct trace_iterator
*iter
= file
->private_data
;
3848 mutex_lock(&trace_types_lock
);
3850 if (iter
->trace
->pipe_close
)
3851 iter
->trace
->pipe_close(iter
);
3853 mutex_unlock(&trace_types_lock
);
3855 free_cpumask_var(iter
->started
);
3856 mutex_destroy(&iter
->mutex
);
3864 trace_poll(struct trace_iterator
*iter
, struct file
*filp
, poll_table
*poll_table
)
3866 /* Iterators are static, they should be filled or empty */
3867 if (trace_buffer_iter(iter
, iter
->cpu_file
))
3868 return POLLIN
| POLLRDNORM
;
3870 if (trace_flags
& TRACE_ITER_BLOCK
)
3872 * Always select as readable when in blocking mode
3874 return POLLIN
| POLLRDNORM
;
3876 return ring_buffer_poll_wait(iter
->trace_buffer
->buffer
, iter
->cpu_file
,
3881 tracing_poll_pipe(struct file
*filp
, poll_table
*poll_table
)
3883 struct trace_iterator
*iter
= filp
->private_data
;
3885 return trace_poll(iter
, filp
, poll_table
);
3889 * This is a make-shift waitqueue.
3890 * A tracer might use this callback on some rare cases:
3892 * 1) the current tracer might hold the runqueue lock when it wakes up
3893 * a reader, hence a deadlock (sched, function, and function graph tracers)
3894 * 2) the function tracers, trace all functions, we don't want
3895 * the overhead of calling wake_up and friends
3896 * (and tracing them too)
3898 * Anyway, this is really very primitive wakeup.
3900 void poll_wait_pipe(struct trace_iterator
*iter
)
3902 set_current_state(TASK_INTERRUPTIBLE
);
3903 /* sleep for 100 msecs, and try again. */
3904 schedule_timeout(HZ
/ 10);
3907 /* Must be called with trace_types_lock mutex held. */
3908 static int tracing_wait_pipe(struct file
*filp
)
3910 struct trace_iterator
*iter
= filp
->private_data
;
3912 while (trace_empty(iter
)) {
3914 if ((filp
->f_flags
& O_NONBLOCK
)) {
3918 mutex_unlock(&iter
->mutex
);
3920 iter
->trace
->wait_pipe(iter
);
3922 mutex_lock(&iter
->mutex
);
3924 if (signal_pending(current
))
3928 * We block until we read something and tracing is disabled.
3929 * We still block if tracing is disabled, but we have never
3930 * read anything. This allows a user to cat this file, and
3931 * then enable tracing. But after we have read something,
3932 * we give an EOF when tracing is again disabled.
3934 * iter->pos will be 0 if we haven't read anything.
3936 if (!tracing_is_enabled() && iter
->pos
)
3947 tracing_read_pipe(struct file
*filp
, char __user
*ubuf
,
3948 size_t cnt
, loff_t
*ppos
)
3950 struct trace_iterator
*iter
= filp
->private_data
;
3951 struct trace_array
*tr
= iter
->tr
;
3954 /* return any leftover data */
3955 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
3959 trace_seq_init(&iter
->seq
);
3961 /* copy the tracer to avoid using a global lock all around */
3962 mutex_lock(&trace_types_lock
);
3963 if (unlikely(iter
->trace
->name
!= tr
->current_trace
->name
))
3964 *iter
->trace
= *tr
->current_trace
;
3965 mutex_unlock(&trace_types_lock
);
3968 * Avoid more than one consumer on a single file descriptor
3969 * This is just a matter of traces coherency, the ring buffer itself
3972 mutex_lock(&iter
->mutex
);
3973 if (iter
->trace
->read
) {
3974 sret
= iter
->trace
->read(iter
, filp
, ubuf
, cnt
, ppos
);
3980 sret
= tracing_wait_pipe(filp
);
3984 /* stop when tracing is finished */
3985 if (trace_empty(iter
)) {
3990 if (cnt
>= PAGE_SIZE
)
3991 cnt
= PAGE_SIZE
- 1;
3993 /* reset all but tr, trace, and overruns */
3994 memset(&iter
->seq
, 0,
3995 sizeof(struct trace_iterator
) -
3996 offsetof(struct trace_iterator
, seq
));
3999 trace_event_read_lock();
4000 trace_access_lock(iter
->cpu_file
);
4001 while (trace_find_next_entry_inc(iter
) != NULL
) {
4002 enum print_line_t ret
;
4003 int len
= iter
->seq
.len
;
4005 ret
= print_trace_line(iter
);
4006 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
4007 /* don't print partial lines */
4008 iter
->seq
.len
= len
;
4011 if (ret
!= TRACE_TYPE_NO_CONSUME
)
4012 trace_consume(iter
);
4014 if (iter
->seq
.len
>= cnt
)
4018 * Setting the full flag means we reached the trace_seq buffer
4019 * size and we should leave by partial output condition above.
4020 * One of the trace_seq_* functions is not used properly.
4022 WARN_ONCE(iter
->seq
.full
, "full flag set for trace type %d",
4025 trace_access_unlock(iter
->cpu_file
);
4026 trace_event_read_unlock();
4028 /* Now copy what we have to the user */
4029 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
4030 if (iter
->seq
.readpos
>= iter
->seq
.len
)
4031 trace_seq_init(&iter
->seq
);
4034 * If there was nothing to send to user, in spite of consuming trace
4035 * entries, go back to wait for more entries.
4041 mutex_unlock(&iter
->mutex
);
4046 static void tracing_pipe_buf_release(struct pipe_inode_info
*pipe
,
4047 struct pipe_buffer
*buf
)
4049 __free_page(buf
->page
);
4052 static void tracing_spd_release_pipe(struct splice_pipe_desc
*spd
,
4055 __free_page(spd
->pages
[idx
]);
4058 static const struct pipe_buf_operations tracing_pipe_buf_ops
= {
4060 .map
= generic_pipe_buf_map
,
4061 .unmap
= generic_pipe_buf_unmap
,
4062 .confirm
= generic_pipe_buf_confirm
,
4063 .release
= tracing_pipe_buf_release
,
4064 .steal
= generic_pipe_buf_steal
,
4065 .get
= generic_pipe_buf_get
,
4069 tracing_fill_pipe_page(size_t rem
, struct trace_iterator
*iter
)
4074 /* Seq buffer is page-sized, exactly what we need. */
4076 count
= iter
->seq
.len
;
4077 ret
= print_trace_line(iter
);
4078 count
= iter
->seq
.len
- count
;
4081 iter
->seq
.len
-= count
;
4084 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
4085 iter
->seq
.len
-= count
;
4089 if (ret
!= TRACE_TYPE_NO_CONSUME
)
4090 trace_consume(iter
);
4092 if (!trace_find_next_entry_inc(iter
)) {
4102 static ssize_t
tracing_splice_read_pipe(struct file
*filp
,
4104 struct pipe_inode_info
*pipe
,
4108 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
4109 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
4110 struct trace_iterator
*iter
= filp
->private_data
;
4111 struct splice_pipe_desc spd
= {
4113 .partial
= partial_def
,
4114 .nr_pages
= 0, /* This gets updated below. */
4115 .nr_pages_max
= PIPE_DEF_BUFFERS
,
4117 .ops
= &tracing_pipe_buf_ops
,
4118 .spd_release
= tracing_spd_release_pipe
,
4120 struct trace_array
*tr
= iter
->tr
;
4125 if (splice_grow_spd(pipe
, &spd
))
4128 /* copy the tracer to avoid using a global lock all around */
4129 mutex_lock(&trace_types_lock
);
4130 if (unlikely(iter
->trace
->name
!= tr
->current_trace
->name
))
4131 *iter
->trace
= *tr
->current_trace
;
4132 mutex_unlock(&trace_types_lock
);
4134 mutex_lock(&iter
->mutex
);
4136 if (iter
->trace
->splice_read
) {
4137 ret
= iter
->trace
->splice_read(iter
, filp
,
4138 ppos
, pipe
, len
, flags
);
4143 ret
= tracing_wait_pipe(filp
);
4147 if (!iter
->ent
&& !trace_find_next_entry_inc(iter
)) {
4152 trace_event_read_lock();
4153 trace_access_lock(iter
->cpu_file
);
4155 /* Fill as many pages as possible. */
4156 for (i
= 0, rem
= len
; i
< pipe
->buffers
&& rem
; i
++) {
4157 spd
.pages
[i
] = alloc_page(GFP_KERNEL
);
4161 rem
= tracing_fill_pipe_page(rem
, iter
);
4163 /* Copy the data into the page, so we can start over. */
4164 ret
= trace_seq_to_buffer(&iter
->seq
,
4165 page_address(spd
.pages
[i
]),
4168 __free_page(spd
.pages
[i
]);
4171 spd
.partial
[i
].offset
= 0;
4172 spd
.partial
[i
].len
= iter
->seq
.len
;
4174 trace_seq_init(&iter
->seq
);
4177 trace_access_unlock(iter
->cpu_file
);
4178 trace_event_read_unlock();
4179 mutex_unlock(&iter
->mutex
);
4183 ret
= splice_to_pipe(pipe
, &spd
);
4185 splice_shrink_spd(&spd
);
4189 mutex_unlock(&iter
->mutex
);
4194 tracing_entries_read(struct file
*filp
, char __user
*ubuf
,
4195 size_t cnt
, loff_t
*ppos
)
4197 struct trace_cpu
*tc
= filp
->private_data
;
4198 struct trace_array
*tr
= tc
->tr
;
4203 mutex_lock(&trace_types_lock
);
4205 if (tc
->cpu
== RING_BUFFER_ALL_CPUS
) {
4206 int cpu
, buf_size_same
;
4211 /* check if all cpu sizes are same */
4212 for_each_tracing_cpu(cpu
) {
4213 /* fill in the size from first enabled cpu */
4215 size
= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
;
4216 if (size
!= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
) {
4222 if (buf_size_same
) {
4223 if (!ring_buffer_expanded
)
4224 r
= sprintf(buf
, "%lu (expanded: %lu)\n",
4226 trace_buf_size
>> 10);
4228 r
= sprintf(buf
, "%lu\n", size
>> 10);
4230 r
= sprintf(buf
, "X\n");
4232 r
= sprintf(buf
, "%lu\n", per_cpu_ptr(tr
->trace_buffer
.data
, tc
->cpu
)->entries
>> 10);
4234 mutex_unlock(&trace_types_lock
);
4236 ret
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
4241 tracing_entries_write(struct file
*filp
, const char __user
*ubuf
,
4242 size_t cnt
, loff_t
*ppos
)
4244 struct trace_cpu
*tc
= filp
->private_data
;
4248 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
4252 /* must have at least 1 entry */
4256 /* value is in KB */
4259 ret
= tracing_resize_ring_buffer(tc
->tr
, val
, tc
->cpu
);
4269 tracing_total_entries_read(struct file
*filp
, char __user
*ubuf
,
4270 size_t cnt
, loff_t
*ppos
)
4272 struct trace_array
*tr
= filp
->private_data
;
4275 unsigned long size
= 0, expanded_size
= 0;
4277 mutex_lock(&trace_types_lock
);
4278 for_each_tracing_cpu(cpu
) {
4279 size
+= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->entries
>> 10;
4280 if (!ring_buffer_expanded
)
4281 expanded_size
+= trace_buf_size
>> 10;
4283 if (ring_buffer_expanded
)
4284 r
= sprintf(buf
, "%lu\n", size
);
4286 r
= sprintf(buf
, "%lu (expanded: %lu)\n", size
, expanded_size
);
4287 mutex_unlock(&trace_types_lock
);
4289 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
4293 tracing_free_buffer_write(struct file
*filp
, const char __user
*ubuf
,
4294 size_t cnt
, loff_t
*ppos
)
4297 * There is no need to read what the user has written, this function
4298 * is just to make sure that there is no error when "echo" is used
4307 tracing_free_buffer_release(struct inode
*inode
, struct file
*filp
)
4309 struct trace_array
*tr
= inode
->i_private
;
4311 /* disable tracing ? */
4312 if (trace_flags
& TRACE_ITER_STOP_ON_FREE
)
4314 /* resize the ring buffer to 0 */
4315 tracing_resize_ring_buffer(tr
, 0, RING_BUFFER_ALL_CPUS
);
4321 tracing_mark_write(struct file
*filp
, const char __user
*ubuf
,
4322 size_t cnt
, loff_t
*fpos
)
4324 unsigned long addr
= (unsigned long)ubuf
;
4325 struct ring_buffer_event
*event
;
4326 struct ring_buffer
*buffer
;
4327 struct print_entry
*entry
;
4328 unsigned long irq_flags
;
4329 struct page
*pages
[2];
4339 if (tracing_disabled
)
4342 if (!(trace_flags
& TRACE_ITER_MARKERS
))
4345 if (cnt
> TRACE_BUF_SIZE
)
4346 cnt
= TRACE_BUF_SIZE
;
4349 * Userspace is injecting traces into the kernel trace buffer.
4350 * We want to be as non intrusive as possible.
4351 * To do so, we do not want to allocate any special buffers
4352 * or take any locks, but instead write the userspace data
4353 * straight into the ring buffer.
4355 * First we need to pin the userspace buffer into memory,
4356 * which, most likely it is, because it just referenced it.
4357 * But there's no guarantee that it is. By using get_user_pages_fast()
4358 * and kmap_atomic/kunmap_atomic() we can get access to the
4359 * pages directly. We then write the data directly into the
4362 BUILD_BUG_ON(TRACE_BUF_SIZE
>= PAGE_SIZE
);
4364 /* check if we cross pages */
4365 if ((addr
& PAGE_MASK
) != ((addr
+ cnt
) & PAGE_MASK
))
4368 offset
= addr
& (PAGE_SIZE
- 1);
4371 ret
= get_user_pages_fast(addr
, nr_pages
, 0, pages
);
4372 if (ret
< nr_pages
) {
4374 put_page(pages
[ret
]);
4379 for (i
= 0; i
< nr_pages
; i
++)
4380 map_page
[i
] = kmap_atomic(pages
[i
]);
4382 local_save_flags(irq_flags
);
4383 size
= sizeof(*entry
) + cnt
+ 2; /* possible \n added */
4384 buffer
= global_trace
.trace_buffer
.buffer
;
4385 event
= trace_buffer_lock_reserve(buffer
, TRACE_PRINT
, size
,
4386 irq_flags
, preempt_count());
4388 /* Ring buffer disabled, return as if not open for write */
4393 entry
= ring_buffer_event_data(event
);
4394 entry
->ip
= _THIS_IP_
;
4396 if (nr_pages
== 2) {
4397 len
= PAGE_SIZE
- offset
;
4398 memcpy(&entry
->buf
, map_page
[0] + offset
, len
);
4399 memcpy(&entry
->buf
[len
], map_page
[1], cnt
- len
);
4401 memcpy(&entry
->buf
, map_page
[0] + offset
, cnt
);
4403 if (entry
->buf
[cnt
- 1] != '\n') {
4404 entry
->buf
[cnt
] = '\n';
4405 entry
->buf
[cnt
+ 1] = '\0';
4407 entry
->buf
[cnt
] = '\0';
4409 __buffer_unlock_commit(buffer
, event
);
4416 for (i
= 0; i
< nr_pages
; i
++){
4417 kunmap_atomic(map_page
[i
]);
4424 static int tracing_clock_show(struct seq_file
*m
, void *v
)
4426 struct trace_array
*tr
= m
->private;
4429 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++)
4431 "%s%s%s%s", i
? " " : "",
4432 i
== tr
->clock_id
? "[" : "", trace_clocks
[i
].name
,
4433 i
== tr
->clock_id
? "]" : "");
4439 static ssize_t
tracing_clock_write(struct file
*filp
, const char __user
*ubuf
,
4440 size_t cnt
, loff_t
*fpos
)
4442 struct seq_file
*m
= filp
->private_data
;
4443 struct trace_array
*tr
= m
->private;
4445 const char *clockstr
;
4448 if (cnt
>= sizeof(buf
))
4451 if (copy_from_user(&buf
, ubuf
, cnt
))
4456 clockstr
= strstrip(buf
);
4458 for (i
= 0; i
< ARRAY_SIZE(trace_clocks
); i
++) {
4459 if (strcmp(trace_clocks
[i
].name
, clockstr
) == 0)
4462 if (i
== ARRAY_SIZE(trace_clocks
))
4465 mutex_lock(&trace_types_lock
);
4469 ring_buffer_set_clock(tr
->trace_buffer
.buffer
, trace_clocks
[i
].func
);
4472 * New clock may not be consistent with the previous clock.
4473 * Reset the buffer so that it doesn't have incomparable timestamps.
4475 tracing_reset_online_cpus(&global_trace
.trace_buffer
);
4477 #ifdef CONFIG_TRACER_MAX_TRACE
4478 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
&& tr
->max_buffer
.buffer
)
4479 ring_buffer_set_clock(tr
->max_buffer
.buffer
, trace_clocks
[i
].func
);
4480 tracing_reset_online_cpus(&global_trace
.max_buffer
);
4483 mutex_unlock(&trace_types_lock
);
4490 static int tracing_clock_open(struct inode
*inode
, struct file
*file
)
4492 if (tracing_disabled
)
4495 return single_open(file
, tracing_clock_show
, inode
->i_private
);
4498 struct ftrace_buffer_info
{
4499 struct trace_iterator iter
;
4504 #ifdef CONFIG_TRACER_SNAPSHOT
4505 static int tracing_snapshot_open(struct inode
*inode
, struct file
*file
)
4507 struct trace_cpu
*tc
= inode
->i_private
;
4508 struct trace_iterator
*iter
;
4512 if (file
->f_mode
& FMODE_READ
) {
4513 iter
= __tracing_open(inode
, file
, true);
4515 ret
= PTR_ERR(iter
);
4517 /* Writes still need the seq_file to hold the private data */
4518 m
= kzalloc(sizeof(*m
), GFP_KERNEL
);
4521 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
4527 iter
->trace_buffer
= &tc
->tr
->max_buffer
;
4528 iter
->cpu_file
= tc
->cpu
;
4530 file
->private_data
= m
;
4537 tracing_snapshot_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
4540 struct seq_file
*m
= filp
->private_data
;
4541 struct trace_iterator
*iter
= m
->private;
4542 struct trace_array
*tr
= iter
->tr
;
4546 ret
= tracing_update_buffers();
4550 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
4554 mutex_lock(&trace_types_lock
);
4556 if (tr
->current_trace
->use_max_tr
) {
4563 if (iter
->cpu_file
!= RING_BUFFER_ALL_CPUS
) {
4567 if (tr
->allocated_snapshot
)
4571 /* Only allow per-cpu swap if the ring buffer supports it */
4572 #ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
4573 if (iter
->cpu_file
!= RING_BUFFER_ALL_CPUS
) {
4578 if (!tr
->allocated_snapshot
) {
4579 ret
= alloc_snapshot(tr
);
4583 local_irq_disable();
4584 /* Now, we're going to swap */
4585 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
)
4586 update_max_tr(tr
, current
, smp_processor_id());
4588 update_max_tr_single(tr
, current
, iter
->cpu_file
);
4592 if (tr
->allocated_snapshot
) {
4593 if (iter
->cpu_file
== RING_BUFFER_ALL_CPUS
)
4594 tracing_reset_online_cpus(&tr
->max_buffer
);
4596 tracing_reset(&tr
->max_buffer
, iter
->cpu_file
);
4606 mutex_unlock(&trace_types_lock
);
4610 static int tracing_snapshot_release(struct inode
*inode
, struct file
*file
)
4612 struct seq_file
*m
= file
->private_data
;
4614 if (file
->f_mode
& FMODE_READ
)
4615 return tracing_release(inode
, file
);
4617 /* If write only, the seq_file is just a stub */
4625 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
);
4626 static ssize_t
tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
4627 size_t count
, loff_t
*ppos
);
4628 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
);
4629 static ssize_t
tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
4630 struct pipe_inode_info
*pipe
, size_t len
, unsigned int flags
);
4632 static int snapshot_raw_open(struct inode
*inode
, struct file
*filp
)
4634 struct ftrace_buffer_info
*info
;
4637 ret
= tracing_buffers_open(inode
, filp
);
4641 info
= filp
->private_data
;
4643 if (info
->iter
.trace
->use_max_tr
) {
4644 tracing_buffers_release(inode
, filp
);
4648 info
->iter
.snapshot
= true;
4649 info
->iter
.trace_buffer
= &info
->iter
.tr
->max_buffer
;
4654 #endif /* CONFIG_TRACER_SNAPSHOT */
4657 static const struct file_operations tracing_max_lat_fops
= {
4658 .open
= tracing_open_generic
,
4659 .read
= tracing_max_lat_read
,
4660 .write
= tracing_max_lat_write
,
4661 .llseek
= generic_file_llseek
,
4664 static const struct file_operations set_tracer_fops
= {
4665 .open
= tracing_open_generic
,
4666 .read
= tracing_set_trace_read
,
4667 .write
= tracing_set_trace_write
,
4668 .llseek
= generic_file_llseek
,
4671 static const struct file_operations tracing_pipe_fops
= {
4672 .open
= tracing_open_pipe
,
4673 .poll
= tracing_poll_pipe
,
4674 .read
= tracing_read_pipe
,
4675 .splice_read
= tracing_splice_read_pipe
,
4676 .release
= tracing_release_pipe
,
4677 .llseek
= no_llseek
,
4680 static const struct file_operations tracing_entries_fops
= {
4681 .open
= tracing_open_generic
,
4682 .read
= tracing_entries_read
,
4683 .write
= tracing_entries_write
,
4684 .llseek
= generic_file_llseek
,
4687 static const struct file_operations tracing_total_entries_fops
= {
4688 .open
= tracing_open_generic
,
4689 .read
= tracing_total_entries_read
,
4690 .llseek
= generic_file_llseek
,
4693 static const struct file_operations tracing_free_buffer_fops
= {
4694 .write
= tracing_free_buffer_write
,
4695 .release
= tracing_free_buffer_release
,
4698 static const struct file_operations tracing_mark_fops
= {
4699 .open
= tracing_open_generic
,
4700 .write
= tracing_mark_write
,
4701 .llseek
= generic_file_llseek
,
4704 static const struct file_operations trace_clock_fops
= {
4705 .open
= tracing_clock_open
,
4707 .llseek
= seq_lseek
,
4708 .release
= single_release
,
4709 .write
= tracing_clock_write
,
4712 #ifdef CONFIG_TRACER_SNAPSHOT
4713 static const struct file_operations snapshot_fops
= {
4714 .open
= tracing_snapshot_open
,
4716 .write
= tracing_snapshot_write
,
4717 .llseek
= tracing_seek
,
4718 .release
= tracing_snapshot_release
,
4721 static const struct file_operations snapshot_raw_fops
= {
4722 .open
= snapshot_raw_open
,
4723 .read
= tracing_buffers_read
,
4724 .release
= tracing_buffers_release
,
4725 .splice_read
= tracing_buffers_splice_read
,
4726 .llseek
= no_llseek
,
4729 #endif /* CONFIG_TRACER_SNAPSHOT */
4731 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
)
4733 struct trace_cpu
*tc
= inode
->i_private
;
4734 struct trace_array
*tr
= tc
->tr
;
4735 struct ftrace_buffer_info
*info
;
4737 if (tracing_disabled
)
4740 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
4744 mutex_lock(&trace_types_lock
);
4749 info
->iter
.cpu_file
= tc
->cpu
;
4750 info
->iter
.trace
= tr
->current_trace
;
4751 info
->iter
.trace_buffer
= &tr
->trace_buffer
;
4753 /* Force reading ring buffer for first read */
4754 info
->read
= (unsigned int)-1;
4756 filp
->private_data
= info
;
4758 mutex_unlock(&trace_types_lock
);
4760 return nonseekable_open(inode
, filp
);
4764 tracing_buffers_poll(struct file
*filp
, poll_table
*poll_table
)
4766 struct ftrace_buffer_info
*info
= filp
->private_data
;
4767 struct trace_iterator
*iter
= &info
->iter
;
4769 return trace_poll(iter
, filp
, poll_table
);
4773 tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
4774 size_t count
, loff_t
*ppos
)
4776 struct ftrace_buffer_info
*info
= filp
->private_data
;
4777 struct trace_iterator
*iter
= &info
->iter
;
4784 mutex_lock(&trace_types_lock
);
4786 #ifdef CONFIG_TRACER_MAX_TRACE
4787 if (iter
->snapshot
&& iter
->tr
->current_trace
->use_max_tr
) {
4794 info
->spare
= ring_buffer_alloc_read_page(iter
->trace_buffer
->buffer
,
4800 /* Do we have previous read data to read? */
4801 if (info
->read
< PAGE_SIZE
)
4805 trace_access_lock(iter
->cpu_file
);
4806 ret
= ring_buffer_read_page(iter
->trace_buffer
->buffer
,
4810 trace_access_unlock(iter
->cpu_file
);
4813 if (trace_empty(iter
)) {
4814 if ((filp
->f_flags
& O_NONBLOCK
)) {
4818 mutex_unlock(&trace_types_lock
);
4819 iter
->trace
->wait_pipe(iter
);
4820 mutex_lock(&trace_types_lock
);
4821 if (signal_pending(current
)) {
4833 size
= PAGE_SIZE
- info
->read
;
4837 ret
= copy_to_user(ubuf
, info
->spare
+ info
->read
, size
);
4848 mutex_unlock(&trace_types_lock
);
4853 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
)
4855 struct ftrace_buffer_info
*info
= file
->private_data
;
4856 struct trace_iterator
*iter
= &info
->iter
;
4858 mutex_lock(&trace_types_lock
);
4860 WARN_ON(!iter
->tr
->ref
);
4864 ring_buffer_free_read_page(iter
->trace_buffer
->buffer
, info
->spare
);
4867 mutex_unlock(&trace_types_lock
);
4873 struct ring_buffer
*buffer
;
4878 static void buffer_pipe_buf_release(struct pipe_inode_info
*pipe
,
4879 struct pipe_buffer
*buf
)
4881 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
4886 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
4891 static void buffer_pipe_buf_get(struct pipe_inode_info
*pipe
,
4892 struct pipe_buffer
*buf
)
4894 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
4899 /* Pipe buffer operations for a buffer. */
4900 static const struct pipe_buf_operations buffer_pipe_buf_ops
= {
4902 .map
= generic_pipe_buf_map
,
4903 .unmap
= generic_pipe_buf_unmap
,
4904 .confirm
= generic_pipe_buf_confirm
,
4905 .release
= buffer_pipe_buf_release
,
4906 .steal
= generic_pipe_buf_steal
,
4907 .get
= buffer_pipe_buf_get
,
4911 * Callback from splice_to_pipe(), if we need to release some pages
4912 * at the end of the spd in case we error'ed out in filling the pipe.
4914 static void buffer_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
4916 struct buffer_ref
*ref
=
4917 (struct buffer_ref
*)spd
->partial
[i
].private;
4922 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
4924 spd
->partial
[i
].private = 0;
4928 tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
4929 struct pipe_inode_info
*pipe
, size_t len
,
4932 struct ftrace_buffer_info
*info
= file
->private_data
;
4933 struct trace_iterator
*iter
= &info
->iter
;
4934 struct partial_page partial_def
[PIPE_DEF_BUFFERS
];
4935 struct page
*pages_def
[PIPE_DEF_BUFFERS
];
4936 struct splice_pipe_desc spd
= {
4938 .partial
= partial_def
,
4939 .nr_pages_max
= PIPE_DEF_BUFFERS
,
4941 .ops
= &buffer_pipe_buf_ops
,
4942 .spd_release
= buffer_spd_release
,
4944 struct buffer_ref
*ref
;
4945 int entries
, size
, i
;
4948 mutex_lock(&trace_types_lock
);
4950 #ifdef CONFIG_TRACER_MAX_TRACE
4951 if (iter
->snapshot
&& iter
->tr
->current_trace
->use_max_tr
) {
4957 if (splice_grow_spd(pipe
, &spd
)) {
4962 if (*ppos
& (PAGE_SIZE
- 1)) {
4967 if (len
& (PAGE_SIZE
- 1)) {
4968 if (len
< PAGE_SIZE
) {
4976 trace_access_lock(iter
->cpu_file
);
4977 entries
= ring_buffer_entries_cpu(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
4979 for (i
= 0; i
< pipe
->buffers
&& len
&& entries
; i
++, len
-= PAGE_SIZE
) {
4983 ref
= kzalloc(sizeof(*ref
), GFP_KERNEL
);
4988 ref
->buffer
= iter
->trace_buffer
->buffer
;
4989 ref
->page
= ring_buffer_alloc_read_page(ref
->buffer
, iter
->cpu_file
);
4995 r
= ring_buffer_read_page(ref
->buffer
, &ref
->page
,
4996 len
, iter
->cpu_file
, 1);
4998 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
5004 * zero out any left over data, this is going to
5007 size
= ring_buffer_page_len(ref
->page
);
5008 if (size
< PAGE_SIZE
)
5009 memset(ref
->page
+ size
, 0, PAGE_SIZE
- size
);
5011 page
= virt_to_page(ref
->page
);
5013 spd
.pages
[i
] = page
;
5014 spd
.partial
[i
].len
= PAGE_SIZE
;
5015 spd
.partial
[i
].offset
= 0;
5016 spd
.partial
[i
].private = (unsigned long)ref
;
5020 entries
= ring_buffer_entries_cpu(iter
->trace_buffer
->buffer
, iter
->cpu_file
);
5023 trace_access_unlock(iter
->cpu_file
);
5026 /* did we read anything? */
5027 if (!spd
.nr_pages
) {
5028 if ((file
->f_flags
& O_NONBLOCK
) || (flags
& SPLICE_F_NONBLOCK
)) {
5032 mutex_unlock(&trace_types_lock
);
5033 iter
->trace
->wait_pipe(iter
);
5034 mutex_lock(&trace_types_lock
);
5035 if (signal_pending(current
)) {
5042 ret
= splice_to_pipe(pipe
, &spd
);
5043 splice_shrink_spd(&spd
);
5045 mutex_unlock(&trace_types_lock
);
5050 static const struct file_operations tracing_buffers_fops
= {
5051 .open
= tracing_buffers_open
,
5052 .read
= tracing_buffers_read
,
5053 .poll
= tracing_buffers_poll
,
5054 .release
= tracing_buffers_release
,
5055 .splice_read
= tracing_buffers_splice_read
,
5056 .llseek
= no_llseek
,
5060 tracing_stats_read(struct file
*filp
, char __user
*ubuf
,
5061 size_t count
, loff_t
*ppos
)
5063 struct trace_cpu
*tc
= filp
->private_data
;
5064 struct trace_array
*tr
= tc
->tr
;
5065 struct trace_buffer
*trace_buf
= &tr
->trace_buffer
;
5066 struct trace_seq
*s
;
5068 unsigned long long t
;
5069 unsigned long usec_rem
;
5072 s
= kmalloc(sizeof(*s
), GFP_KERNEL
);
5078 cnt
= ring_buffer_entries_cpu(trace_buf
->buffer
, cpu
);
5079 trace_seq_printf(s
, "entries: %ld\n", cnt
);
5081 cnt
= ring_buffer_overrun_cpu(trace_buf
->buffer
, cpu
);
5082 trace_seq_printf(s
, "overrun: %ld\n", cnt
);
5084 cnt
= ring_buffer_commit_overrun_cpu(trace_buf
->buffer
, cpu
);
5085 trace_seq_printf(s
, "commit overrun: %ld\n", cnt
);
5087 cnt
= ring_buffer_bytes_cpu(trace_buf
->buffer
, cpu
);
5088 trace_seq_printf(s
, "bytes: %ld\n", cnt
);
5090 if (trace_clocks
[trace_clock_id
].in_ns
) {
5091 /* local or global for trace_clock */
5092 t
= ns2usecs(ring_buffer_oldest_event_ts(trace_buf
->buffer
, cpu
));
5093 usec_rem
= do_div(t
, USEC_PER_SEC
);
5094 trace_seq_printf(s
, "oldest event ts: %5llu.%06lu\n",
5097 t
= ns2usecs(ring_buffer_time_stamp(trace_buf
->buffer
, cpu
));
5098 usec_rem
= do_div(t
, USEC_PER_SEC
);
5099 trace_seq_printf(s
, "now ts: %5llu.%06lu\n", t
, usec_rem
);
5101 /* counter or tsc mode for trace_clock */
5102 trace_seq_printf(s
, "oldest event ts: %llu\n",
5103 ring_buffer_oldest_event_ts(trace_buf
->buffer
, cpu
));
5105 trace_seq_printf(s
, "now ts: %llu\n",
5106 ring_buffer_time_stamp(trace_buf
->buffer
, cpu
));
5109 cnt
= ring_buffer_dropped_events_cpu(trace_buf
->buffer
, cpu
);
5110 trace_seq_printf(s
, "dropped events: %ld\n", cnt
);
5112 cnt
= ring_buffer_read_events_cpu(trace_buf
->buffer
, cpu
);
5113 trace_seq_printf(s
, "read events: %ld\n", cnt
);
5115 count
= simple_read_from_buffer(ubuf
, count
, ppos
, s
->buffer
, s
->len
);
5122 static const struct file_operations tracing_stats_fops
= {
5123 .open
= tracing_open_generic
,
5124 .read
= tracing_stats_read
,
5125 .llseek
= generic_file_llseek
,
5128 #ifdef CONFIG_DYNAMIC_FTRACE
5130 int __weak
ftrace_arch_read_dyn_info(char *buf
, int size
)
5136 tracing_read_dyn_info(struct file
*filp
, char __user
*ubuf
,
5137 size_t cnt
, loff_t
*ppos
)
5139 static char ftrace_dyn_info_buffer
[1024];
5140 static DEFINE_MUTEX(dyn_info_mutex
);
5141 unsigned long *p
= filp
->private_data
;
5142 char *buf
= ftrace_dyn_info_buffer
;
5143 int size
= ARRAY_SIZE(ftrace_dyn_info_buffer
);
5146 mutex_lock(&dyn_info_mutex
);
5147 r
= sprintf(buf
, "%ld ", *p
);
5149 r
+= ftrace_arch_read_dyn_info(buf
+r
, (size
-1)-r
);
5152 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
5154 mutex_unlock(&dyn_info_mutex
);
5159 static const struct file_operations tracing_dyn_info_fops
= {
5160 .open
= tracing_open_generic
,
5161 .read
= tracing_read_dyn_info
,
5162 .llseek
= generic_file_llseek
,
5164 #endif /* CONFIG_DYNAMIC_FTRACE */
5166 #if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
5168 ftrace_snapshot(unsigned long ip
, unsigned long parent_ip
, void **data
)
5174 ftrace_count_snapshot(unsigned long ip
, unsigned long parent_ip
, void **data
)
5176 unsigned long *count
= (long *)data
;
5188 ftrace_snapshot_print(struct seq_file
*m
, unsigned long ip
,
5189 struct ftrace_probe_ops
*ops
, void *data
)
5191 long count
= (long)data
;
5193 seq_printf(m
, "%ps:", (void *)ip
);
5195 seq_printf(m
, "snapshot");
5198 seq_printf(m
, ":unlimited\n");
5200 seq_printf(m
, ":count=%ld\n", count
);
5205 static struct ftrace_probe_ops snapshot_probe_ops
= {
5206 .func
= ftrace_snapshot
,
5207 .print
= ftrace_snapshot_print
,
5210 static struct ftrace_probe_ops snapshot_count_probe_ops
= {
5211 .func
= ftrace_count_snapshot
,
5212 .print
= ftrace_snapshot_print
,
5216 ftrace_trace_snapshot_callback(struct ftrace_hash
*hash
,
5217 char *glob
, char *cmd
, char *param
, int enable
)
5219 struct ftrace_probe_ops
*ops
;
5220 void *count
= (void *)-1;
5224 /* hash funcs only work with set_ftrace_filter */
5228 ops
= param
? &snapshot_count_probe_ops
: &snapshot_probe_ops
;
5230 if (glob
[0] == '!') {
5231 unregister_ftrace_function_probe_func(glob
+1, ops
);
5238 number
= strsep(¶m
, ":");
5240 if (!strlen(number
))
5244 * We use the callback data field (which is a pointer)
5247 ret
= kstrtoul(number
, 0, (unsigned long *)&count
);
5252 ret
= register_ftrace_function_probe(glob
, ops
, count
);
5255 alloc_snapshot(&global_trace
);
5257 return ret
< 0 ? ret
: 0;
5260 static struct ftrace_func_command ftrace_snapshot_cmd
= {
5262 .func
= ftrace_trace_snapshot_callback
,
5265 static int register_snapshot_cmd(void)
5267 return register_ftrace_command(&ftrace_snapshot_cmd
);
5270 static inline int register_snapshot_cmd(void) { return 0; }
5271 #endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
5273 struct dentry
*tracing_init_dentry_tr(struct trace_array
*tr
)
5278 if (!debugfs_initialized())
5281 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
)
5282 tr
->dir
= debugfs_create_dir("tracing", NULL
);
5285 pr_warn_once("Could not create debugfs directory 'tracing'\n");
5290 struct dentry
*tracing_init_dentry(void)
5292 return tracing_init_dentry_tr(&global_trace
);
5295 static struct dentry
*tracing_dentry_percpu(struct trace_array
*tr
, int cpu
)
5297 struct dentry
*d_tracer
;
5300 return tr
->percpu_dir
;
5302 d_tracer
= tracing_init_dentry_tr(tr
);
5306 tr
->percpu_dir
= debugfs_create_dir("per_cpu", d_tracer
);
5308 WARN_ONCE(!tr
->percpu_dir
,
5309 "Could not create debugfs directory 'per_cpu/%d'\n", cpu
);
5311 return tr
->percpu_dir
;
5315 tracing_init_debugfs_percpu(struct trace_array
*tr
, long cpu
)
5317 struct trace_array_cpu
*data
= per_cpu_ptr(tr
->trace_buffer
.data
, cpu
);
5318 struct dentry
*d_percpu
= tracing_dentry_percpu(tr
, cpu
);
5319 struct dentry
*d_cpu
;
5320 char cpu_dir
[30]; /* 30 characters should be more than enough */
5325 snprintf(cpu_dir
, 30, "cpu%ld", cpu
);
5326 d_cpu
= debugfs_create_dir(cpu_dir
, d_percpu
);
5328 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir
);
5332 /* per cpu trace_pipe */
5333 trace_create_file("trace_pipe", 0444, d_cpu
,
5334 (void *)&data
->trace_cpu
, &tracing_pipe_fops
);
5337 trace_create_file("trace", 0644, d_cpu
,
5338 (void *)&data
->trace_cpu
, &tracing_fops
);
5340 trace_create_file("trace_pipe_raw", 0444, d_cpu
,
5341 (void *)&data
->trace_cpu
, &tracing_buffers_fops
);
5343 trace_create_file("stats", 0444, d_cpu
,
5344 (void *)&data
->trace_cpu
, &tracing_stats_fops
);
5346 trace_create_file("buffer_size_kb", 0444, d_cpu
,
5347 (void *)&data
->trace_cpu
, &tracing_entries_fops
);
5349 #ifdef CONFIG_TRACER_SNAPSHOT
5350 trace_create_file("snapshot", 0644, d_cpu
,
5351 (void *)&data
->trace_cpu
, &snapshot_fops
);
5353 trace_create_file("snapshot_raw", 0444, d_cpu
,
5354 (void *)&data
->trace_cpu
, &snapshot_raw_fops
);
5358 #ifdef CONFIG_FTRACE_SELFTEST
5359 /* Let selftest have access to static functions in this file */
5360 #include "trace_selftest.c"
5363 struct trace_option_dentry
{
5364 struct tracer_opt
*opt
;
5365 struct tracer_flags
*flags
;
5366 struct trace_array
*tr
;
5367 struct dentry
*entry
;
5371 trace_options_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
5374 struct trace_option_dentry
*topt
= filp
->private_data
;
5377 if (topt
->flags
->val
& topt
->opt
->bit
)
5382 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
5386 trace_options_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
5389 struct trace_option_dentry
*topt
= filp
->private_data
;
5393 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5397 if (val
!= 0 && val
!= 1)
5400 if (!!(topt
->flags
->val
& topt
->opt
->bit
) != val
) {
5401 mutex_lock(&trace_types_lock
);
5402 ret
= __set_tracer_option(topt
->tr
->current_trace
, topt
->flags
,
5404 mutex_unlock(&trace_types_lock
);
5415 static const struct file_operations trace_options_fops
= {
5416 .open
= tracing_open_generic
,
5417 .read
= trace_options_read
,
5418 .write
= trace_options_write
,
5419 .llseek
= generic_file_llseek
,
5423 trace_options_core_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
5426 long index
= (long)filp
->private_data
;
5429 if (trace_flags
& (1 << index
))
5434 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
5438 trace_options_core_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
5441 struct trace_array
*tr
= &global_trace
;
5442 long index
= (long)filp
->private_data
;
5446 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5450 if (val
!= 0 && val
!= 1)
5453 mutex_lock(&trace_types_lock
);
5454 ret
= set_tracer_flag(tr
, 1 << index
, val
);
5455 mutex_unlock(&trace_types_lock
);
5465 static const struct file_operations trace_options_core_fops
= {
5466 .open
= tracing_open_generic
,
5467 .read
= trace_options_core_read
,
5468 .write
= trace_options_core_write
,
5469 .llseek
= generic_file_llseek
,
5472 struct dentry
*trace_create_file(const char *name
,
5474 struct dentry
*parent
,
5476 const struct file_operations
*fops
)
5480 ret
= debugfs_create_file(name
, mode
, parent
, data
, fops
);
5482 pr_warning("Could not create debugfs '%s' entry\n", name
);
5488 static struct dentry
*trace_options_init_dentry(struct trace_array
*tr
)
5490 struct dentry
*d_tracer
;
5495 d_tracer
= tracing_init_dentry_tr(tr
);
5499 tr
->options
= debugfs_create_dir("options", d_tracer
);
5501 pr_warning("Could not create debugfs directory 'options'\n");
5509 create_trace_option_file(struct trace_array
*tr
,
5510 struct trace_option_dentry
*topt
,
5511 struct tracer_flags
*flags
,
5512 struct tracer_opt
*opt
)
5514 struct dentry
*t_options
;
5516 t_options
= trace_options_init_dentry(tr
);
5520 topt
->flags
= flags
;
5524 topt
->entry
= trace_create_file(opt
->name
, 0644, t_options
, topt
,
5525 &trace_options_fops
);
5529 static struct trace_option_dentry
*
5530 create_trace_option_files(struct trace_array
*tr
, struct tracer
*tracer
)
5532 struct trace_option_dentry
*topts
;
5533 struct tracer_flags
*flags
;
5534 struct tracer_opt
*opts
;
5540 flags
= tracer
->flags
;
5542 if (!flags
|| !flags
->opts
)
5547 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
5550 topts
= kcalloc(cnt
+ 1, sizeof(*topts
), GFP_KERNEL
);
5554 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
5555 create_trace_option_file(tr
, &topts
[cnt
], flags
,
5562 destroy_trace_option_files(struct trace_option_dentry
*topts
)
5569 for (cnt
= 0; topts
[cnt
].opt
; cnt
++) {
5570 if (topts
[cnt
].entry
)
5571 debugfs_remove(topts
[cnt
].entry
);
5577 static struct dentry
*
5578 create_trace_option_core_file(struct trace_array
*tr
,
5579 const char *option
, long index
)
5581 struct dentry
*t_options
;
5583 t_options
= trace_options_init_dentry(tr
);
5587 return trace_create_file(option
, 0644, t_options
, (void *)index
,
5588 &trace_options_core_fops
);
5591 static __init
void create_trace_options_dir(struct trace_array
*tr
)
5593 struct dentry
*t_options
;
5596 t_options
= trace_options_init_dentry(tr
);
5600 for (i
= 0; trace_options
[i
]; i
++)
5601 create_trace_option_core_file(tr
, trace_options
[i
], i
);
5605 rb_simple_read(struct file
*filp
, char __user
*ubuf
,
5606 size_t cnt
, loff_t
*ppos
)
5608 struct trace_array
*tr
= filp
->private_data
;
5609 struct ring_buffer
*buffer
= tr
->trace_buffer
.buffer
;
5614 r
= ring_buffer_record_is_on(buffer
);
5618 r
= sprintf(buf
, "%d\n", r
);
5620 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
5624 rb_simple_write(struct file
*filp
, const char __user
*ubuf
,
5625 size_t cnt
, loff_t
*ppos
)
5627 struct trace_array
*tr
= filp
->private_data
;
5628 struct ring_buffer
*buffer
= tr
->trace_buffer
.buffer
;
5632 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
5637 mutex_lock(&trace_types_lock
);
5639 ring_buffer_record_on(buffer
);
5640 if (tr
->current_trace
->start
)
5641 tr
->current_trace
->start(tr
);
5643 ring_buffer_record_off(buffer
);
5644 if (tr
->current_trace
->stop
)
5645 tr
->current_trace
->stop(tr
);
5647 mutex_unlock(&trace_types_lock
);
5655 static const struct file_operations rb_simple_fops
= {
5656 .open
= tracing_open_generic
,
5657 .read
= rb_simple_read
,
5658 .write
= rb_simple_write
,
5659 .llseek
= default_llseek
,
5662 struct dentry
*trace_instance_dir
;
5665 init_tracer_debugfs(struct trace_array
*tr
, struct dentry
*d_tracer
);
5667 static void init_trace_buffers(struct trace_array
*tr
, struct trace_buffer
*buf
)
5671 for_each_tracing_cpu(cpu
) {
5672 memset(per_cpu_ptr(buf
->data
, cpu
), 0, sizeof(struct trace_array_cpu
));
5673 per_cpu_ptr(buf
->data
, cpu
)->trace_cpu
.cpu
= cpu
;
5674 per_cpu_ptr(buf
->data
, cpu
)->trace_cpu
.tr
= tr
;
5679 allocate_trace_buffer(struct trace_array
*tr
, struct trace_buffer
*buf
, int size
)
5681 enum ring_buffer_flags rb_flags
;
5683 rb_flags
= trace_flags
& TRACE_ITER_OVERWRITE
? RB_FL_OVERWRITE
: 0;
5685 buf
->buffer
= ring_buffer_alloc(size
, rb_flags
);
5689 buf
->data
= alloc_percpu(struct trace_array_cpu
);
5691 ring_buffer_free(buf
->buffer
);
5695 init_trace_buffers(tr
, buf
);
5697 /* Allocate the first page for all buffers */
5698 set_buffer_entries(&tr
->trace_buffer
,
5699 ring_buffer_size(tr
->trace_buffer
.buffer
, 0));
5704 static int allocate_trace_buffers(struct trace_array
*tr
, int size
)
5708 ret
= allocate_trace_buffer(tr
, &tr
->trace_buffer
, size
);
5712 #ifdef CONFIG_TRACER_MAX_TRACE
5713 ret
= allocate_trace_buffer(tr
, &tr
->max_buffer
,
5714 allocate_snapshot
? size
: 1);
5716 ring_buffer_free(tr
->trace_buffer
.buffer
);
5717 free_percpu(tr
->trace_buffer
.data
);
5720 tr
->allocated_snapshot
= allocate_snapshot
;
5723 * Only the top level trace array gets its snapshot allocated
5724 * from the kernel command line.
5726 allocate_snapshot
= false;
5731 static int new_instance_create(const char *name
)
5733 struct trace_array
*tr
;
5736 mutex_lock(&trace_types_lock
);
5739 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
5740 if (tr
->name
&& strcmp(tr
->name
, name
) == 0)
5745 tr
= kzalloc(sizeof(*tr
), GFP_KERNEL
);
5749 tr
->name
= kstrdup(name
, GFP_KERNEL
);
5753 raw_spin_lock_init(&tr
->start_lock
);
5755 tr
->current_trace
= &nop_trace
;
5757 INIT_LIST_HEAD(&tr
->systems
);
5758 INIT_LIST_HEAD(&tr
->events
);
5760 if (allocate_trace_buffers(tr
, trace_buf_size
) < 0)
5763 /* Holder for file callbacks */
5764 tr
->trace_cpu
.cpu
= RING_BUFFER_ALL_CPUS
;
5765 tr
->trace_cpu
.tr
= tr
;
5767 tr
->dir
= debugfs_create_dir(name
, trace_instance_dir
);
5771 ret
= event_trace_add_tracer(tr
->dir
, tr
);
5775 init_tracer_debugfs(tr
, tr
->dir
);
5777 list_add(&tr
->list
, &ftrace_trace_arrays
);
5779 mutex_unlock(&trace_types_lock
);
5784 if (tr
->trace_buffer
.buffer
)
5785 ring_buffer_free(tr
->trace_buffer
.buffer
);
5790 mutex_unlock(&trace_types_lock
);
5796 static int instance_delete(const char *name
)
5798 struct trace_array
*tr
;
5802 mutex_lock(&trace_types_lock
);
5805 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
5806 if (tr
->name
&& strcmp(tr
->name
, name
) == 0) {
5818 list_del(&tr
->list
);
5820 event_trace_del_tracer(tr
);
5821 debugfs_remove_recursive(tr
->dir
);
5822 free_percpu(tr
->trace_buffer
.data
);
5823 ring_buffer_free(tr
->trace_buffer
.buffer
);
5831 mutex_unlock(&trace_types_lock
);
5836 static int instance_mkdir (struct inode
*inode
, struct dentry
*dentry
, umode_t mode
)
5838 struct dentry
*parent
;
5841 /* Paranoid: Make sure the parent is the "instances" directory */
5842 parent
= hlist_entry(inode
->i_dentry
.first
, struct dentry
, d_alias
);
5843 if (WARN_ON_ONCE(parent
!= trace_instance_dir
))
5847 * The inode mutex is locked, but debugfs_create_dir() will also
5848 * take the mutex. As the instances directory can not be destroyed
5849 * or changed in any other way, it is safe to unlock it, and
5850 * let the dentry try. If two users try to make the same dir at
5851 * the same time, then the new_instance_create() will determine the
5854 mutex_unlock(&inode
->i_mutex
);
5856 ret
= new_instance_create(dentry
->d_iname
);
5858 mutex_lock(&inode
->i_mutex
);
5863 static int instance_rmdir(struct inode
*inode
, struct dentry
*dentry
)
5865 struct dentry
*parent
;
5868 /* Paranoid: Make sure the parent is the "instances" directory */
5869 parent
= hlist_entry(inode
->i_dentry
.first
, struct dentry
, d_alias
);
5870 if (WARN_ON_ONCE(parent
!= trace_instance_dir
))
5873 /* The caller did a dget() on dentry */
5874 mutex_unlock(&dentry
->d_inode
->i_mutex
);
5877 * The inode mutex is locked, but debugfs_create_dir() will also
5878 * take the mutex. As the instances directory can not be destroyed
5879 * or changed in any other way, it is safe to unlock it, and
5880 * let the dentry try. If two users try to make the same dir at
5881 * the same time, then the instance_delete() will determine the
5884 mutex_unlock(&inode
->i_mutex
);
5886 ret
= instance_delete(dentry
->d_iname
);
5888 mutex_lock_nested(&inode
->i_mutex
, I_MUTEX_PARENT
);
5889 mutex_lock(&dentry
->d_inode
->i_mutex
);
5894 static const struct inode_operations instance_dir_inode_operations
= {
5895 .lookup
= simple_lookup
,
5896 .mkdir
= instance_mkdir
,
5897 .rmdir
= instance_rmdir
,
5900 static __init
void create_trace_instances(struct dentry
*d_tracer
)
5902 trace_instance_dir
= debugfs_create_dir("instances", d_tracer
);
5903 if (WARN_ON(!trace_instance_dir
))
5906 /* Hijack the dir inode operations, to allow mkdir */
5907 trace_instance_dir
->d_inode
->i_op
= &instance_dir_inode_operations
;
5911 init_tracer_debugfs(struct trace_array
*tr
, struct dentry
*d_tracer
)
5915 trace_create_file("trace_options", 0644, d_tracer
,
5916 tr
, &tracing_iter_fops
);
5918 trace_create_file("trace", 0644, d_tracer
,
5919 (void *)&tr
->trace_cpu
, &tracing_fops
);
5921 trace_create_file("trace_pipe", 0444, d_tracer
,
5922 (void *)&tr
->trace_cpu
, &tracing_pipe_fops
);
5924 trace_create_file("buffer_size_kb", 0644, d_tracer
,
5925 (void *)&tr
->trace_cpu
, &tracing_entries_fops
);
5927 trace_create_file("buffer_total_size_kb", 0444, d_tracer
,
5928 tr
, &tracing_total_entries_fops
);
5930 trace_create_file("free_buffer", 0644, d_tracer
,
5931 tr
, &tracing_free_buffer_fops
);
5933 trace_create_file("trace_marker", 0220, d_tracer
,
5934 tr
, &tracing_mark_fops
);
5936 trace_create_file("trace_clock", 0644, d_tracer
, tr
,
5939 trace_create_file("tracing_on", 0644, d_tracer
,
5940 tr
, &rb_simple_fops
);
5942 #ifdef CONFIG_TRACER_SNAPSHOT
5943 trace_create_file("snapshot", 0644, d_tracer
,
5944 (void *)&tr
->trace_cpu
, &snapshot_fops
);
5947 for_each_tracing_cpu(cpu
)
5948 tracing_init_debugfs_percpu(tr
, cpu
);
5952 static __init
int tracer_init_debugfs(void)
5954 struct dentry
*d_tracer
;
5956 trace_access_lock_init();
5958 d_tracer
= tracing_init_dentry();
5962 init_tracer_debugfs(&global_trace
, d_tracer
);
5964 trace_create_file("tracing_cpumask", 0644, d_tracer
,
5965 &global_trace
, &tracing_cpumask_fops
);
5967 trace_create_file("available_tracers", 0444, d_tracer
,
5968 &global_trace
, &show_traces_fops
);
5970 trace_create_file("current_tracer", 0644, d_tracer
,
5971 &global_trace
, &set_tracer_fops
);
5973 #ifdef CONFIG_TRACER_MAX_TRACE
5974 trace_create_file("tracing_max_latency", 0644, d_tracer
,
5975 &tracing_max_latency
, &tracing_max_lat_fops
);
5978 trace_create_file("tracing_thresh", 0644, d_tracer
,
5979 &tracing_thresh
, &tracing_max_lat_fops
);
5981 trace_create_file("README", 0444, d_tracer
,
5982 NULL
, &tracing_readme_fops
);
5984 trace_create_file("saved_cmdlines", 0444, d_tracer
,
5985 NULL
, &tracing_saved_cmdlines_fops
);
5987 #ifdef CONFIG_DYNAMIC_FTRACE
5988 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
5989 &ftrace_update_tot_cnt
, &tracing_dyn_info_fops
);
5992 create_trace_instances(d_tracer
);
5994 create_trace_options_dir(&global_trace
);
5999 static int trace_panic_handler(struct notifier_block
*this,
6000 unsigned long event
, void *unused
)
6002 if (ftrace_dump_on_oops
)
6003 ftrace_dump(ftrace_dump_on_oops
);
6007 static struct notifier_block trace_panic_notifier
= {
6008 .notifier_call
= trace_panic_handler
,
6010 .priority
= 150 /* priority: INT_MAX >= x >= 0 */
6013 static int trace_die_handler(struct notifier_block
*self
,
6019 if (ftrace_dump_on_oops
)
6020 ftrace_dump(ftrace_dump_on_oops
);
6028 static struct notifier_block trace_die_notifier
= {
6029 .notifier_call
= trace_die_handler
,
6034 * printk is set to max of 1024, we really don't need it that big.
6035 * Nothing should be printing 1000 characters anyway.
6037 #define TRACE_MAX_PRINT 1000
6040 * Define here KERN_TRACE so that we have one place to modify
6041 * it if we decide to change what log level the ftrace dump
6044 #define KERN_TRACE KERN_EMERG
6047 trace_printk_seq(struct trace_seq
*s
)
6049 /* Probably should print a warning here. */
6050 if (s
->len
>= TRACE_MAX_PRINT
)
6051 s
->len
= TRACE_MAX_PRINT
;
6053 /* should be zero ended, but we are paranoid. */
6054 s
->buffer
[s
->len
] = 0;
6056 printk(KERN_TRACE
"%s", s
->buffer
);
6061 void trace_init_global_iter(struct trace_iterator
*iter
)
6063 iter
->tr
= &global_trace
;
6064 iter
->trace
= iter
->tr
->current_trace
;
6065 iter
->cpu_file
= RING_BUFFER_ALL_CPUS
;
6066 iter
->trace_buffer
= &global_trace
.trace_buffer
;
6069 void ftrace_dump(enum ftrace_dump_mode oops_dump_mode
)
6071 /* use static because iter can be a bit big for the stack */
6072 static struct trace_iterator iter
;
6073 static atomic_t dump_running
;
6074 unsigned int old_userobj
;
6075 unsigned long flags
;
6078 /* Only allow one dump user at a time. */
6079 if (atomic_inc_return(&dump_running
) != 1) {
6080 atomic_dec(&dump_running
);
6085 * Always turn off tracing when we dump.
6086 * We don't need to show trace output of what happens
6087 * between multiple crashes.
6089 * If the user does a sysrq-z, then they can re-enable
6090 * tracing with echo 1 > tracing_on.
6094 local_irq_save(flags
);
6096 /* Simulate the iterator */
6097 trace_init_global_iter(&iter
);
6099 for_each_tracing_cpu(cpu
) {
6100 atomic_inc(&per_cpu_ptr(iter
.tr
->trace_buffer
.data
, cpu
)->disabled
);
6103 old_userobj
= trace_flags
& TRACE_ITER_SYM_USEROBJ
;
6105 /* don't look at user memory in panic mode */
6106 trace_flags
&= ~TRACE_ITER_SYM_USEROBJ
;
6108 switch (oops_dump_mode
) {
6110 iter
.cpu_file
= RING_BUFFER_ALL_CPUS
;
6113 iter
.cpu_file
= raw_smp_processor_id();
6118 printk(KERN_TRACE
"Bad dumping mode, switching to all CPUs dump\n");
6119 iter
.cpu_file
= RING_BUFFER_ALL_CPUS
;
6122 printk(KERN_TRACE
"Dumping ftrace buffer:\n");
6124 /* Did function tracer already get disabled? */
6125 if (ftrace_is_dead()) {
6126 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
6127 printk("# MAY BE MISSING FUNCTION EVENTS\n");
6131 * We need to stop all tracing on all CPUS to read the
6132 * the next buffer. This is a bit expensive, but is
6133 * not done often. We fill all what we can read,
6134 * and then release the locks again.
6137 while (!trace_empty(&iter
)) {
6140 printk(KERN_TRACE
"---------------------------------\n");
6144 /* reset all but tr, trace, and overruns */
6145 memset(&iter
.seq
, 0,
6146 sizeof(struct trace_iterator
) -
6147 offsetof(struct trace_iterator
, seq
));
6148 iter
.iter_flags
|= TRACE_FILE_LAT_FMT
;
6151 if (trace_find_next_entry_inc(&iter
) != NULL
) {
6154 ret
= print_trace_line(&iter
);
6155 if (ret
!= TRACE_TYPE_NO_CONSUME
)
6156 trace_consume(&iter
);
6158 touch_nmi_watchdog();
6160 trace_printk_seq(&iter
.seq
);
6164 printk(KERN_TRACE
" (ftrace buffer empty)\n");
6166 printk(KERN_TRACE
"---------------------------------\n");
6169 trace_flags
|= old_userobj
;
6171 for_each_tracing_cpu(cpu
) {
6172 atomic_dec(&per_cpu_ptr(iter
.trace_buffer
->data
, cpu
)->disabled
);
6174 atomic_dec(&dump_running
);
6175 local_irq_restore(flags
);
6177 EXPORT_SYMBOL_GPL(ftrace_dump
);
6179 __init
static int tracer_alloc_buffers(void)
6185 if (!alloc_cpumask_var(&tracing_buffer_mask
, GFP_KERNEL
))
6188 if (!alloc_cpumask_var(&tracing_cpumask
, GFP_KERNEL
))
6189 goto out_free_buffer_mask
;
6191 /* Only allocate trace_printk buffers if a trace_printk exists */
6192 if (__stop___trace_bprintk_fmt
!= __start___trace_bprintk_fmt
)
6193 /* Must be called before global_trace.buffer is allocated */
6194 trace_printk_init_buffers();
6196 /* To save memory, keep the ring buffer size to its minimum */
6197 if (ring_buffer_expanded
)
6198 ring_buf_size
= trace_buf_size
;
6202 cpumask_copy(tracing_buffer_mask
, cpu_possible_mask
);
6203 cpumask_copy(tracing_cpumask
, cpu_all_mask
);
6205 raw_spin_lock_init(&global_trace
.start_lock
);
6207 /* TODO: make the number of buffers hot pluggable with CPUS */
6208 if (allocate_trace_buffers(&global_trace
, ring_buf_size
) < 0) {
6209 printk(KERN_ERR
"tracer: failed to allocate ring buffer!\n");
6211 goto out_free_cpumask
;
6214 if (global_trace
.buffer_disabled
)
6217 trace_init_cmdlines();
6220 * register_tracer() might reference current_trace, so it
6221 * needs to be set before we register anything. This is
6222 * just a bootstrap of current_trace anyway.
6224 global_trace
.current_trace
= &nop_trace
;
6226 register_tracer(&nop_trace
);
6228 /* All seems OK, enable tracing */
6229 tracing_disabled
= 0;
6231 atomic_notifier_chain_register(&panic_notifier_list
,
6232 &trace_panic_notifier
);
6234 register_die_notifier(&trace_die_notifier
);
6236 global_trace
.flags
= TRACE_ARRAY_FL_GLOBAL
;
6238 /* Holder for file callbacks */
6239 global_trace
.trace_cpu
.cpu
= RING_BUFFER_ALL_CPUS
;
6240 global_trace
.trace_cpu
.tr
= &global_trace
;
6242 INIT_LIST_HEAD(&global_trace
.systems
);
6243 INIT_LIST_HEAD(&global_trace
.events
);
6244 list_add(&global_trace
.list
, &ftrace_trace_arrays
);
6246 while (trace_boot_options
) {
6249 option
= strsep(&trace_boot_options
, ",");
6250 trace_set_options(&global_trace
, option
);
6253 register_snapshot_cmd();
6258 free_percpu(global_trace
.trace_buffer
.data
);
6259 #ifdef CONFIG_TRACER_MAX_TRACE
6260 free_percpu(global_trace
.max_buffer
.data
);
6262 free_cpumask_var(tracing_cpumask
);
6263 out_free_buffer_mask
:
6264 free_cpumask_var(tracing_buffer_mask
);
6269 __init
static int clear_boot_tracer(void)
6272 * The default tracer at boot buffer is an init section.
6273 * This function is called in lateinit. If we did not
6274 * find the boot tracer, then clear it out, to prevent
6275 * later registration from accessing the buffer that is
6276 * about to be freed.
6278 if (!default_bootup_tracer
)
6281 printk(KERN_INFO
"ftrace bootup tracer '%s' not registered.\n",
6282 default_bootup_tracer
);
6283 default_bootup_tracer
= NULL
;
6288 early_initcall(tracer_alloc_buffers
);
6289 fs_initcall(tracer_init_debugfs
);
6290 late_initcall(clear_boot_tracer
);