2 * ring buffer based function tracer
4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
7 * Originally taken from the RT patch by:
8 * Arnaldo Carvalho de Melo <acme@redhat.com>
10 * Based on code from the latency_tracer, that is:
11 * Copyright (C) 2004-2006 Ingo Molnar
12 * Copyright (C) 2004 William Lee Irwin III
14 #include <linux/ring_buffer.h>
15 #include <linux/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/ctype.h>
34 #include <linux/init.h>
35 #include <linux/poll.h>
36 #include <linux/gfp.h>
40 #include "trace_output.h"
42 #define TRACE_BUFFER_FLAGS (RB_FL_OVERWRITE)
44 unsigned long __read_mostly tracing_max_latency
;
45 unsigned long __read_mostly tracing_thresh
;
48 * We need to change this state when a selftest is running.
49 * A selftest will lurk into the ring-buffer to count the
50 * entries inserted during the selftest although some concurrent
51 * insertions into the ring-buffer such as ftrace_printk could occurred
52 * at the same time, giving false positive or negative results.
54 static bool __read_mostly tracing_selftest_running
;
57 * If a tracer is running, we do not want to run SELFTEST.
59 static bool __read_mostly tracing_selftest_disabled
;
61 /* For tracers that don't implement custom flags */
62 static struct tracer_opt dummy_tracer_opt
[] = {
66 static struct tracer_flags dummy_tracer_flags
= {
68 .opts
= dummy_tracer_opt
71 static int dummy_set_flag(u32 old_flags
, u32 bit
, int set
)
77 * Kill all tracing for good (never come back).
78 * It is initialized to 1 but will turn to zero if the initialization
79 * of the tracer is successful. But that is the only place that sets
82 static int tracing_disabled
= 1;
84 static DEFINE_PER_CPU(local_t
, ftrace_cpu_disabled
);
86 static inline void ftrace_disable_cpu(void)
89 local_inc(&__get_cpu_var(ftrace_cpu_disabled
));
92 static inline void ftrace_enable_cpu(void)
94 local_dec(&__get_cpu_var(ftrace_cpu_disabled
));
98 static cpumask_var_t __read_mostly tracing_buffer_mask
;
100 /* Define which cpu buffers are currently read in trace_pipe */
101 static cpumask_var_t tracing_reader_cpumask
;
103 #define for_each_tracing_cpu(cpu) \
104 for_each_cpu(cpu, tracing_buffer_mask)
107 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
109 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
110 * is set, then ftrace_dump is called. This will output the contents
111 * of the ftrace buffers to the console. This is very useful for
112 * capturing traces that lead to crashes and outputing it to a
115 * It is default off, but you can enable it with either specifying
116 * "ftrace_dump_on_oops" in the kernel command line, or setting
117 * /proc/sys/kernel/ftrace_dump_on_oops to true.
119 int ftrace_dump_on_oops
;
121 static int tracing_set_tracer(const char *buf
);
123 #define BOOTUP_TRACER_SIZE 100
124 static char bootup_tracer_buf
[BOOTUP_TRACER_SIZE
] __initdata
;
125 static char *default_bootup_tracer
;
127 static int __init
set_ftrace(char *str
)
129 strncpy(bootup_tracer_buf
, str
, BOOTUP_TRACER_SIZE
);
130 default_bootup_tracer
= bootup_tracer_buf
;
133 __setup("ftrace=", set_ftrace
);
135 static int __init
set_ftrace_dump_on_oops(char *str
)
137 ftrace_dump_on_oops
= 1;
140 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops
);
143 ns2usecs(cycle_t nsec
)
150 cycle_t
ftrace_now(int cpu
)
152 u64 ts
= ring_buffer_time_stamp(cpu
);
153 ring_buffer_normalize_time_stamp(cpu
, &ts
);
158 * The global_trace is the descriptor that holds the tracing
159 * buffers for the live tracing. For each CPU, it contains
160 * a link list of pages that will store trace entries. The
161 * page descriptor of the pages in the memory is used to hold
162 * the link list by linking the lru item in the page descriptor
163 * to each of the pages in the buffer per CPU.
165 * For each active CPU there is a data field that holds the
166 * pages for the buffer for that CPU. Each CPU has the same number
167 * of pages allocated for its buffer.
169 static struct trace_array global_trace
;
171 static DEFINE_PER_CPU(struct trace_array_cpu
, global_trace_cpu
);
174 * The max_tr is used to snapshot the global_trace when a maximum
175 * latency is reached. Some tracers will use this to store a maximum
176 * trace while it continues examining live traces.
178 * The buffers for the max_tr are set up the same as the global_trace.
179 * When a snapshot is taken, the link list of the max_tr is swapped
180 * with the link list of the global_trace and the buffers are reset for
181 * the global_trace so the tracing can continue.
183 static struct trace_array max_tr
;
185 static DEFINE_PER_CPU(struct trace_array_cpu
, max_data
);
187 /* tracer_enabled is used to toggle activation of a tracer */
188 static int tracer_enabled
= 1;
191 * tracing_is_enabled - return tracer_enabled status
193 * This function is used by other tracers to know the status
194 * of the tracer_enabled flag. Tracers may use this function
195 * to know if it should enable their features when starting
196 * up. See irqsoff tracer for an example (start_irqsoff_tracer).
198 int tracing_is_enabled(void)
200 return tracer_enabled
;
204 * trace_buf_size is the size in bytes that is allocated
205 * for a buffer. Note, the number of bytes is always rounded
208 * This number is purposely set to a low number of 16384.
209 * If the dump on oops happens, it will be much appreciated
210 * to not have to wait for all that output. Anyway this can be
211 * boot time and run time configurable.
213 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
215 static unsigned long trace_buf_size
= TRACE_BUF_SIZE_DEFAULT
;
217 /* trace_types holds a link list of available tracers. */
218 static struct tracer
*trace_types __read_mostly
;
220 /* current_trace points to the tracer that is currently active */
221 static struct tracer
*current_trace __read_mostly
;
224 * max_tracer_type_len is used to simplify the allocating of
225 * buffers to read userspace tracer names. We keep track of
226 * the longest tracer name registered.
228 static int max_tracer_type_len
;
231 * trace_types_lock is used to protect the trace_types list.
232 * This lock is also used to keep user access serialized.
233 * Accesses from userspace will grab this lock while userspace
234 * activities happen inside the kernel.
236 static DEFINE_MUTEX(trace_types_lock
);
238 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
239 static DECLARE_WAIT_QUEUE_HEAD(trace_wait
);
241 /* trace_flags holds trace_options default values */
242 unsigned long trace_flags
= TRACE_ITER_PRINT_PARENT
| TRACE_ITER_PRINTK
|
243 TRACE_ITER_ANNOTATE
| TRACE_ITER_CONTEXT_INFO
;
246 * trace_wake_up - wake up tasks waiting for trace input
248 * Simply wakes up any task that is blocked on the trace_wait
249 * queue. These is used with trace_poll for tasks polling the trace.
251 void trace_wake_up(void)
254 * The runqueue_is_locked() can fail, but this is the best we
257 if (!(trace_flags
& TRACE_ITER_BLOCK
) && !runqueue_is_locked())
258 wake_up(&trace_wait
);
261 static int __init
set_buf_size(char *str
)
263 unsigned long buf_size
;
268 ret
= strict_strtoul(str
, 0, &buf_size
);
269 /* nr_entries can not be zero */
270 if (ret
< 0 || buf_size
== 0)
272 trace_buf_size
= buf_size
;
275 __setup("trace_buf_size=", set_buf_size
);
277 unsigned long nsecs_to_usecs(unsigned long nsecs
)
282 /* These must match the bit postions in trace_iterator_flags */
283 static const char *trace_options
[] = {
306 * ftrace_max_lock is used to protect the swapping of buffers
307 * when taking a max snapshot. The buffers themselves are
308 * protected by per_cpu spinlocks. But the action of the swap
309 * needs its own lock.
311 * This is defined as a raw_spinlock_t in order to help
312 * with performance when lockdep debugging is enabled.
314 static raw_spinlock_t ftrace_max_lock
=
315 (raw_spinlock_t
)__RAW_SPIN_LOCK_UNLOCKED
;
318 * Copy the new maximum trace into the separate maximum-trace
319 * structure. (this way the maximum trace is permanently saved,
320 * for later retrieval via /debugfs/tracing/latency_trace)
323 __update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
325 struct trace_array_cpu
*data
= tr
->data
[cpu
];
328 max_tr
.time_start
= data
->preempt_timestamp
;
330 data
= max_tr
.data
[cpu
];
331 data
->saved_latency
= tracing_max_latency
;
333 memcpy(data
->comm
, tsk
->comm
, TASK_COMM_LEN
);
334 data
->pid
= tsk
->pid
;
335 data
->uid
= task_uid(tsk
);
336 data
->nice
= tsk
->static_prio
- 20 - MAX_RT_PRIO
;
337 data
->policy
= tsk
->policy
;
338 data
->rt_priority
= tsk
->rt_priority
;
340 /* record this tasks comm */
341 tracing_record_cmdline(tsk
);
344 ssize_t
trace_seq_to_user(struct trace_seq
*s
, char __user
*ubuf
, size_t cnt
)
352 if (s
->len
<= s
->readpos
)
355 len
= s
->len
- s
->readpos
;
358 ret
= copy_to_user(ubuf
, s
->buffer
+ s
->readpos
, cnt
);
368 ssize_t
trace_seq_to_buffer(struct trace_seq
*s
, void *buf
, size_t cnt
)
373 if (s
->len
<= s
->readpos
)
376 len
= s
->len
- s
->readpos
;
379 ret
= memcpy(buf
, s
->buffer
+ s
->readpos
, cnt
);
388 trace_print_seq(struct seq_file
*m
, struct trace_seq
*s
)
390 int len
= s
->len
>= PAGE_SIZE
? PAGE_SIZE
- 1 : s
->len
;
393 seq_puts(m
, s
->buffer
);
399 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
401 * @tsk: the task with the latency
402 * @cpu: The cpu that initiated the trace.
404 * Flip the buffers between the @tr and the max_tr and record information
405 * about which task was the cause of this latency.
408 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
410 struct ring_buffer
*buf
= tr
->buffer
;
412 WARN_ON_ONCE(!irqs_disabled());
413 __raw_spin_lock(&ftrace_max_lock
);
415 tr
->buffer
= max_tr
.buffer
;
418 ftrace_disable_cpu();
419 ring_buffer_reset(tr
->buffer
);
422 __update_max_tr(tr
, tsk
, cpu
);
423 __raw_spin_unlock(&ftrace_max_lock
);
427 * update_max_tr_single - only copy one trace over, and reset the rest
429 * @tsk - task with the latency
430 * @cpu - the cpu of the buffer to copy.
432 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
435 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
439 WARN_ON_ONCE(!irqs_disabled());
440 __raw_spin_lock(&ftrace_max_lock
);
442 ftrace_disable_cpu();
444 ring_buffer_reset(max_tr
.buffer
);
445 ret
= ring_buffer_swap_cpu(max_tr
.buffer
, tr
->buffer
, cpu
);
449 WARN_ON_ONCE(ret
&& ret
!= -EAGAIN
);
451 __update_max_tr(tr
, tsk
, cpu
);
452 __raw_spin_unlock(&ftrace_max_lock
);
456 * register_tracer - register a tracer with the ftrace system.
457 * @type - the plugin for the tracer
459 * Register a new plugin tracer.
461 int register_tracer(struct tracer
*type
)
462 __releases(kernel_lock
)
463 __acquires(kernel_lock
)
470 pr_info("Tracer must have a name\n");
475 * When this gets called we hold the BKL which means that
476 * preemption is disabled. Various trace selftests however
477 * need to disable and enable preemption for successful tests.
478 * So we drop the BKL here and grab it after the tests again.
481 mutex_lock(&trace_types_lock
);
483 tracing_selftest_running
= true;
485 for (t
= trace_types
; t
; t
= t
->next
) {
486 if (strcmp(type
->name
, t
->name
) == 0) {
488 pr_info("Trace %s already registered\n",
496 type
->set_flag
= &dummy_set_flag
;
498 type
->flags
= &dummy_tracer_flags
;
500 if (!type
->flags
->opts
)
501 type
->flags
->opts
= dummy_tracer_opt
;
502 if (!type
->wait_pipe
)
503 type
->wait_pipe
= default_wait_pipe
;
506 #ifdef CONFIG_FTRACE_STARTUP_TEST
507 if (type
->selftest
&& !tracing_selftest_disabled
) {
508 struct tracer
*saved_tracer
= current_trace
;
509 struct trace_array
*tr
= &global_trace
;
513 * Run a selftest on this tracer.
514 * Here we reset the trace buffer, and set the current
515 * tracer to be this tracer. The tracer can then run some
516 * internal tracing to verify that everything is in order.
517 * If we fail, we do not register this tracer.
519 for_each_tracing_cpu(i
)
520 tracing_reset(tr
, i
);
522 current_trace
= type
;
523 /* the test is responsible for initializing and enabling */
524 pr_info("Testing tracer %s: ", type
->name
);
525 ret
= type
->selftest(type
, tr
);
526 /* the test is responsible for resetting too */
527 current_trace
= saved_tracer
;
529 printk(KERN_CONT
"FAILED!\n");
532 /* Only reset on passing, to avoid touching corrupted buffers */
533 for_each_tracing_cpu(i
)
534 tracing_reset(tr
, i
);
536 printk(KERN_CONT
"PASSED\n");
540 type
->next
= trace_types
;
542 len
= strlen(type
->name
);
543 if (len
> max_tracer_type_len
)
544 max_tracer_type_len
= len
;
547 tracing_selftest_running
= false;
548 mutex_unlock(&trace_types_lock
);
550 if (ret
|| !default_bootup_tracer
)
553 if (strncmp(default_bootup_tracer
, type
->name
, BOOTUP_TRACER_SIZE
))
556 printk(KERN_INFO
"Starting tracer '%s'\n", type
->name
);
557 /* Do we want this tracer to start on bootup? */
558 tracing_set_tracer(type
->name
);
559 default_bootup_tracer
= NULL
;
560 /* disable other selftests, since this will break it. */
561 tracing_selftest_disabled
= 1;
562 #ifdef CONFIG_FTRACE_STARTUP_TEST
563 printk(KERN_INFO
"Disabling FTRACE selftests due to running tracer '%s'\n",
572 void unregister_tracer(struct tracer
*type
)
577 mutex_lock(&trace_types_lock
);
578 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
582 pr_info("Trace %s not registered\n", type
->name
);
588 if (type
== current_trace
&& tracer_enabled
) {
591 if (current_trace
->stop
)
592 current_trace
->stop(&global_trace
);
593 current_trace
= &nop_trace
;
596 if (strlen(type
->name
) != max_tracer_type_len
)
599 max_tracer_type_len
= 0;
600 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
601 len
= strlen((*t
)->name
);
602 if (len
> max_tracer_type_len
)
603 max_tracer_type_len
= len
;
606 mutex_unlock(&trace_types_lock
);
609 void tracing_reset(struct trace_array
*tr
, int cpu
)
611 ftrace_disable_cpu();
612 ring_buffer_reset_cpu(tr
->buffer
, cpu
);
616 void tracing_reset_online_cpus(struct trace_array
*tr
)
620 tr
->time_start
= ftrace_now(tr
->cpu
);
622 for_each_online_cpu(cpu
)
623 tracing_reset(tr
, cpu
);
626 #define SAVED_CMDLINES 128
627 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
628 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
629 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
630 static int cmdline_idx
;
631 static raw_spinlock_t trace_cmdline_lock
= __RAW_SPIN_LOCK_UNLOCKED
;
633 /* temporary disable recording */
634 static atomic_t trace_record_cmdline_disabled __read_mostly
;
636 static void trace_init_cmdlines(void)
638 memset(&map_pid_to_cmdline
, -1, sizeof(map_pid_to_cmdline
));
639 memset(&map_cmdline_to_pid
, -1, sizeof(map_cmdline_to_pid
));
643 static int trace_stop_count
;
644 static DEFINE_SPINLOCK(tracing_start_lock
);
647 * ftrace_off_permanent - disable all ftrace code permanently
649 * This should only be called when a serious anomally has
650 * been detected. This will turn off the function tracing,
651 * ring buffers, and other tracing utilites. It takes no
652 * locks and can be called from any context.
654 void ftrace_off_permanent(void)
656 tracing_disabled
= 1;
658 tracing_off_permanent();
662 * tracing_start - quick start of the tracer
664 * If tracing is enabled but was stopped by tracing_stop,
665 * this will start the tracer back up.
667 void tracing_start(void)
669 struct ring_buffer
*buffer
;
672 if (tracing_disabled
)
675 spin_lock_irqsave(&tracing_start_lock
, flags
);
676 if (--trace_stop_count
) {
677 if (trace_stop_count
< 0) {
678 /* Someone screwed up their debugging */
680 trace_stop_count
= 0;
686 buffer
= global_trace
.buffer
;
688 ring_buffer_record_enable(buffer
);
690 buffer
= max_tr
.buffer
;
692 ring_buffer_record_enable(buffer
);
696 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
700 * tracing_stop - quick stop of the tracer
702 * Light weight way to stop tracing. Use in conjunction with
705 void tracing_stop(void)
707 struct ring_buffer
*buffer
;
711 spin_lock_irqsave(&tracing_start_lock
, flags
);
712 if (trace_stop_count
++)
715 buffer
= global_trace
.buffer
;
717 ring_buffer_record_disable(buffer
);
719 buffer
= max_tr
.buffer
;
721 ring_buffer_record_disable(buffer
);
724 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
727 void trace_stop_cmdline_recording(void);
729 static void trace_save_cmdline(struct task_struct
*tsk
)
734 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
738 * It's not the end of the world if we don't get
739 * the lock, but we also don't want to spin
740 * nor do we want to disable interrupts,
741 * so if we miss here, then better luck next time.
743 if (!__raw_spin_trylock(&trace_cmdline_lock
))
746 idx
= map_pid_to_cmdline
[tsk
->pid
];
747 if (idx
>= SAVED_CMDLINES
) {
748 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
750 map
= map_cmdline_to_pid
[idx
];
751 if (map
<= PID_MAX_DEFAULT
)
752 map_pid_to_cmdline
[map
] = (unsigned)-1;
754 map_pid_to_cmdline
[tsk
->pid
] = idx
;
759 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
761 __raw_spin_unlock(&trace_cmdline_lock
);
764 char *trace_find_cmdline(int pid
)
766 char *cmdline
= "<...>";
772 if (pid
> PID_MAX_DEFAULT
)
775 map
= map_pid_to_cmdline
[pid
];
776 if (map
>= SAVED_CMDLINES
)
779 cmdline
= saved_cmdlines
[map
];
785 void tracing_record_cmdline(struct task_struct
*tsk
)
787 if (atomic_read(&trace_record_cmdline_disabled
))
790 trace_save_cmdline(tsk
);
794 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
,
797 struct task_struct
*tsk
= current
;
799 entry
->preempt_count
= pc
& 0xff;
800 entry
->pid
= (tsk
) ? tsk
->pid
: 0;
801 entry
->tgid
= (tsk
) ? tsk
->tgid
: 0;
803 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
804 (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
806 TRACE_FLAG_IRQS_NOSUPPORT
|
808 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
809 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
810 (need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0);
813 struct ring_buffer_event
*trace_buffer_lock_reserve(struct trace_array
*tr
,
816 unsigned long flags
, int pc
)
818 struct ring_buffer_event
*event
;
820 event
= ring_buffer_lock_reserve(tr
->buffer
, len
);
822 struct trace_entry
*ent
= ring_buffer_event_data(event
);
824 tracing_generic_entry_update(ent
, flags
, pc
);
830 static void ftrace_trace_stack(struct trace_array
*tr
,
831 unsigned long flags
, int skip
, int pc
);
832 static void ftrace_trace_userstack(struct trace_array
*tr
,
833 unsigned long flags
, int pc
);
835 void trace_buffer_unlock_commit(struct trace_array
*tr
,
836 struct ring_buffer_event
*event
,
837 unsigned long flags
, int pc
)
839 ring_buffer_unlock_commit(tr
->buffer
, event
);
841 ftrace_trace_stack(tr
, flags
, 6, pc
);
842 ftrace_trace_userstack(tr
, flags
, pc
);
846 struct ring_buffer_event
*
847 trace_current_buffer_lock_reserve(unsigned char type
, unsigned long len
,
848 unsigned long flags
, int pc
)
850 return trace_buffer_lock_reserve(&global_trace
,
851 type
, len
, flags
, pc
);
854 void trace_current_buffer_unlock_commit(struct ring_buffer_event
*event
,
855 unsigned long flags
, int pc
)
857 return trace_buffer_unlock_commit(&global_trace
, event
, flags
, pc
);
861 trace_function(struct trace_array
*tr
,
862 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
865 struct ring_buffer_event
*event
;
866 struct ftrace_entry
*entry
;
868 /* If we are reading the ring buffer, don't trace */
869 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
872 event
= trace_buffer_lock_reserve(tr
, TRACE_FN
, sizeof(*entry
),
876 entry
= ring_buffer_event_data(event
);
878 entry
->parent_ip
= parent_ip
;
879 ring_buffer_unlock_commit(tr
->buffer
, event
);
882 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
883 static void __trace_graph_entry(struct trace_array
*tr
,
884 struct ftrace_graph_ent
*trace
,
888 struct ring_buffer_event
*event
;
889 struct ftrace_graph_ent_entry
*entry
;
891 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
894 event
= trace_buffer_lock_reserve(&global_trace
, TRACE_GRAPH_ENT
,
895 sizeof(*entry
), flags
, pc
);
898 entry
= ring_buffer_event_data(event
);
899 entry
->graph_ent
= *trace
;
900 ring_buffer_unlock_commit(global_trace
.buffer
, event
);
903 static void __trace_graph_return(struct trace_array
*tr
,
904 struct ftrace_graph_ret
*trace
,
908 struct ring_buffer_event
*event
;
909 struct ftrace_graph_ret_entry
*entry
;
911 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
914 event
= trace_buffer_lock_reserve(&global_trace
, TRACE_GRAPH_RET
,
915 sizeof(*entry
), flags
, pc
);
918 entry
= ring_buffer_event_data(event
);
920 ring_buffer_unlock_commit(global_trace
.buffer
, event
);
925 ftrace(struct trace_array
*tr
, struct trace_array_cpu
*data
,
926 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
929 if (likely(!atomic_read(&data
->disabled
)))
930 trace_function(tr
, ip
, parent_ip
, flags
, pc
);
933 static void __ftrace_trace_stack(struct trace_array
*tr
,
937 #ifdef CONFIG_STACKTRACE
938 struct ring_buffer_event
*event
;
939 struct stack_entry
*entry
;
940 struct stack_trace trace
;
942 event
= trace_buffer_lock_reserve(tr
, TRACE_STACK
,
943 sizeof(*entry
), flags
, pc
);
946 entry
= ring_buffer_event_data(event
);
947 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
949 trace
.nr_entries
= 0;
950 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
952 trace
.entries
= entry
->caller
;
954 save_stack_trace(&trace
);
955 ring_buffer_unlock_commit(tr
->buffer
, event
);
959 static void ftrace_trace_stack(struct trace_array
*tr
,
963 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
966 __ftrace_trace_stack(tr
, flags
, skip
, pc
);
969 void __trace_stack(struct trace_array
*tr
,
973 __ftrace_trace_stack(tr
, flags
, skip
, pc
);
976 static void ftrace_trace_userstack(struct trace_array
*tr
,
977 unsigned long flags
, int pc
)
979 #ifdef CONFIG_STACKTRACE
980 struct ring_buffer_event
*event
;
981 struct userstack_entry
*entry
;
982 struct stack_trace trace
;
984 if (!(trace_flags
& TRACE_ITER_USERSTACKTRACE
))
987 event
= trace_buffer_lock_reserve(tr
, TRACE_USER_STACK
,
988 sizeof(*entry
), flags
, pc
);
991 entry
= ring_buffer_event_data(event
);
993 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
995 trace
.nr_entries
= 0;
996 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
998 trace
.entries
= entry
->caller
;
1000 save_stack_trace_user(&trace
);
1001 ring_buffer_unlock_commit(tr
->buffer
, event
);
1006 static void __trace_userstack(struct trace_array
*tr
, unsigned long flags
)
1008 ftrace_trace_userstack(tr
, flags
, preempt_count());
1013 ftrace_trace_special(void *__tr
,
1014 unsigned long arg1
, unsigned long arg2
, unsigned long arg3
,
1017 struct ring_buffer_event
*event
;
1018 struct trace_array
*tr
= __tr
;
1019 struct special_entry
*entry
;
1021 event
= trace_buffer_lock_reserve(tr
, TRACE_SPECIAL
,
1022 sizeof(*entry
), 0, pc
);
1025 entry
= ring_buffer_event_data(event
);
1029 trace_buffer_unlock_commit(tr
, event
, 0, pc
);
1033 __trace_special(void *__tr
, void *__data
,
1034 unsigned long arg1
, unsigned long arg2
, unsigned long arg3
)
1036 ftrace_trace_special(__tr
, arg1
, arg2
, arg3
, preempt_count());
1040 tracing_sched_switch_trace(struct trace_array
*tr
,
1041 struct task_struct
*prev
,
1042 struct task_struct
*next
,
1043 unsigned long flags
, int pc
)
1045 struct ring_buffer_event
*event
;
1046 struct ctx_switch_entry
*entry
;
1048 event
= trace_buffer_lock_reserve(tr
, TRACE_CTX
,
1049 sizeof(*entry
), flags
, pc
);
1052 entry
= ring_buffer_event_data(event
);
1053 entry
->prev_pid
= prev
->pid
;
1054 entry
->prev_prio
= prev
->prio
;
1055 entry
->prev_state
= prev
->state
;
1056 entry
->next_pid
= next
->pid
;
1057 entry
->next_prio
= next
->prio
;
1058 entry
->next_state
= next
->state
;
1059 entry
->next_cpu
= task_cpu(next
);
1060 trace_buffer_unlock_commit(tr
, event
, flags
, pc
);
1064 tracing_sched_wakeup_trace(struct trace_array
*tr
,
1065 struct task_struct
*wakee
,
1066 struct task_struct
*curr
,
1067 unsigned long flags
, int pc
)
1069 struct ring_buffer_event
*event
;
1070 struct ctx_switch_entry
*entry
;
1072 event
= trace_buffer_lock_reserve(tr
, TRACE_WAKE
,
1073 sizeof(*entry
), flags
, pc
);
1076 entry
= ring_buffer_event_data(event
);
1077 entry
->prev_pid
= curr
->pid
;
1078 entry
->prev_prio
= curr
->prio
;
1079 entry
->prev_state
= curr
->state
;
1080 entry
->next_pid
= wakee
->pid
;
1081 entry
->next_prio
= wakee
->prio
;
1082 entry
->next_state
= wakee
->state
;
1083 entry
->next_cpu
= task_cpu(wakee
);
1085 ring_buffer_unlock_commit(tr
->buffer
, event
);
1086 ftrace_trace_stack(tr
, flags
, 6, pc
);
1087 ftrace_trace_userstack(tr
, flags
, pc
);
1091 ftrace_special(unsigned long arg1
, unsigned long arg2
, unsigned long arg3
)
1093 struct trace_array
*tr
= &global_trace
;
1094 struct trace_array_cpu
*data
;
1095 unsigned long flags
;
1099 if (tracing_disabled
)
1102 pc
= preempt_count();
1103 local_irq_save(flags
);
1104 cpu
= raw_smp_processor_id();
1105 data
= tr
->data
[cpu
];
1107 if (likely(atomic_inc_return(&data
->disabled
) == 1))
1108 ftrace_trace_special(tr
, arg1
, arg2
, arg3
, pc
);
1110 atomic_dec(&data
->disabled
);
1111 local_irq_restore(flags
);
1114 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1115 int trace_graph_entry(struct ftrace_graph_ent
*trace
)
1117 struct trace_array
*tr
= &global_trace
;
1118 struct trace_array_cpu
*data
;
1119 unsigned long flags
;
1124 if (!ftrace_trace_task(current
))
1127 if (!ftrace_graph_addr(trace
->func
))
1130 local_irq_save(flags
);
1131 cpu
= raw_smp_processor_id();
1132 data
= tr
->data
[cpu
];
1133 disabled
= atomic_inc_return(&data
->disabled
);
1134 if (likely(disabled
== 1)) {
1135 pc
= preempt_count();
1136 __trace_graph_entry(tr
, trace
, flags
, pc
);
1138 /* Only do the atomic if it is not already set */
1139 if (!test_tsk_trace_graph(current
))
1140 set_tsk_trace_graph(current
);
1141 atomic_dec(&data
->disabled
);
1142 local_irq_restore(flags
);
1147 void trace_graph_return(struct ftrace_graph_ret
*trace
)
1149 struct trace_array
*tr
= &global_trace
;
1150 struct trace_array_cpu
*data
;
1151 unsigned long flags
;
1156 local_irq_save(flags
);
1157 cpu
= raw_smp_processor_id();
1158 data
= tr
->data
[cpu
];
1159 disabled
= atomic_inc_return(&data
->disabled
);
1160 if (likely(disabled
== 1)) {
1161 pc
= preempt_count();
1162 __trace_graph_return(tr
, trace
, flags
, pc
);
1165 clear_tsk_trace_graph(current
);
1166 atomic_dec(&data
->disabled
);
1167 local_irq_restore(flags
);
1169 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1171 enum trace_file_type
{
1172 TRACE_FILE_LAT_FMT
= 1,
1173 TRACE_FILE_ANNOTATE
= 2,
1176 static void trace_iterator_increment(struct trace_iterator
*iter
)
1178 /* Don't allow ftrace to trace into the ring buffers */
1179 ftrace_disable_cpu();
1182 if (iter
->buffer_iter
[iter
->cpu
])
1183 ring_buffer_read(iter
->buffer_iter
[iter
->cpu
], NULL
);
1185 ftrace_enable_cpu();
1188 static struct trace_entry
*
1189 peek_next_entry(struct trace_iterator
*iter
, int cpu
, u64
*ts
)
1191 struct ring_buffer_event
*event
;
1192 struct ring_buffer_iter
*buf_iter
= iter
->buffer_iter
[cpu
];
1194 /* Don't allow ftrace to trace into the ring buffers */
1195 ftrace_disable_cpu();
1198 event
= ring_buffer_iter_peek(buf_iter
, ts
);
1200 event
= ring_buffer_peek(iter
->tr
->buffer
, cpu
, ts
);
1202 ftrace_enable_cpu();
1204 return event
? ring_buffer_event_data(event
) : NULL
;
1207 static struct trace_entry
*
1208 __find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
, u64
*ent_ts
)
1210 struct ring_buffer
*buffer
= iter
->tr
->buffer
;
1211 struct trace_entry
*ent
, *next
= NULL
;
1212 int cpu_file
= iter
->cpu_file
;
1213 u64 next_ts
= 0, ts
;
1218 * If we are in a per_cpu trace file, don't bother by iterating over
1219 * all cpu and peek directly.
1221 if (cpu_file
> TRACE_PIPE_ALL_CPU
) {
1222 if (ring_buffer_empty_cpu(buffer
, cpu_file
))
1224 ent
= peek_next_entry(iter
, cpu_file
, ent_ts
);
1226 *ent_cpu
= cpu_file
;
1231 for_each_tracing_cpu(cpu
) {
1233 if (ring_buffer_empty_cpu(buffer
, cpu
))
1236 ent
= peek_next_entry(iter
, cpu
, &ts
);
1239 * Pick the entry with the smallest timestamp:
1241 if (ent
&& (!next
|| ts
< next_ts
)) {
1249 *ent_cpu
= next_cpu
;
1257 /* Find the next real entry, without updating the iterator itself */
1258 struct trace_entry
*trace_find_next_entry(struct trace_iterator
*iter
,
1259 int *ent_cpu
, u64
*ent_ts
)
1261 return __find_next_entry(iter
, ent_cpu
, ent_ts
);
1264 /* Find the next real entry, and increment the iterator to the next entry */
1265 static void *find_next_entry_inc(struct trace_iterator
*iter
)
1267 iter
->ent
= __find_next_entry(iter
, &iter
->cpu
, &iter
->ts
);
1270 trace_iterator_increment(iter
);
1272 return iter
->ent
? iter
: NULL
;
1275 static void trace_consume(struct trace_iterator
*iter
)
1277 /* Don't allow ftrace to trace into the ring buffers */
1278 ftrace_disable_cpu();
1279 ring_buffer_consume(iter
->tr
->buffer
, iter
->cpu
, &iter
->ts
);
1280 ftrace_enable_cpu();
1283 static void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1285 struct trace_iterator
*iter
= m
->private;
1291 /* can't go backwards */
1296 ent
= find_next_entry_inc(iter
);
1300 while (ent
&& iter
->idx
< i
)
1301 ent
= find_next_entry_inc(iter
);
1309 * No necessary locking here. The worst thing which can
1310 * happen is loosing events consumed at the same time
1311 * by a trace_pipe reader.
1312 * Other than that, we don't risk to crash the ring buffer
1313 * because it serializes the readers.
1315 * The current tracer is copied to avoid a global locking
1318 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
1320 struct trace_iterator
*iter
= m
->private;
1321 static struct tracer
*old_tracer
;
1322 int cpu_file
= iter
->cpu_file
;
1327 /* copy the tracer to avoid using a global lock all around */
1328 mutex_lock(&trace_types_lock
);
1329 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
1330 old_tracer
= current_trace
;
1331 *iter
->trace
= *current_trace
;
1333 mutex_unlock(&trace_types_lock
);
1335 atomic_inc(&trace_record_cmdline_disabled
);
1337 if (*pos
!= iter
->pos
) {
1342 ftrace_disable_cpu();
1344 if (cpu_file
== TRACE_PIPE_ALL_CPU
) {
1345 for_each_tracing_cpu(cpu
)
1346 ring_buffer_iter_reset(iter
->buffer_iter
[cpu
]);
1348 ring_buffer_iter_reset(iter
->buffer_iter
[cpu_file
]);
1351 ftrace_enable_cpu();
1353 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
1358 p
= s_next(m
, p
, &l
);
1364 static void s_stop(struct seq_file
*m
, void *p
)
1366 atomic_dec(&trace_record_cmdline_disabled
);
1369 static void print_lat_help_header(struct seq_file
*m
)
1371 seq_puts(m
, "# _------=> CPU# \n");
1372 seq_puts(m
, "# / _-----=> irqs-off \n");
1373 seq_puts(m
, "# | / _----=> need-resched \n");
1374 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
1375 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
1376 seq_puts(m
, "# |||| / \n");
1377 seq_puts(m
, "# ||||| delay \n");
1378 seq_puts(m
, "# cmd pid ||||| time | caller \n");
1379 seq_puts(m
, "# \\ / ||||| \\ | / \n");
1382 static void print_func_help_header(struct seq_file
*m
)
1384 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1385 seq_puts(m
, "# | | | | |\n");
1390 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
1392 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1393 struct trace_array
*tr
= iter
->tr
;
1394 struct trace_array_cpu
*data
= tr
->data
[tr
->cpu
];
1395 struct tracer
*type
= current_trace
;
1396 unsigned long total
;
1397 unsigned long entries
;
1398 const char *name
= "preemption";
1403 entries
= ring_buffer_entries(iter
->tr
->buffer
);
1405 ring_buffer_overruns(iter
->tr
->buffer
);
1407 seq_printf(m
, "%s latency trace v1.1.5 on %s\n",
1409 seq_puts(m
, "-----------------------------------"
1410 "---------------------------------\n");
1411 seq_printf(m
, " latency: %lu us, #%lu/%lu, CPU#%d |"
1412 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1413 nsecs_to_usecs(data
->saved_latency
),
1417 #if defined(CONFIG_PREEMPT_NONE)
1419 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1421 #elif defined(CONFIG_PREEMPT)
1426 /* These are reserved for later use */
1429 seq_printf(m
, " #P:%d)\n", num_online_cpus());
1433 seq_puts(m
, " -----------------\n");
1434 seq_printf(m
, " | task: %.16s-%d "
1435 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1436 data
->comm
, data
->pid
, data
->uid
, data
->nice
,
1437 data
->policy
, data
->rt_priority
);
1438 seq_puts(m
, " -----------------\n");
1440 if (data
->critical_start
) {
1441 seq_puts(m
, " => started at: ");
1442 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
1443 trace_print_seq(m
, &iter
->seq
);
1444 seq_puts(m
, "\n => ended at: ");
1445 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
1446 trace_print_seq(m
, &iter
->seq
);
1453 static void test_cpu_buff_start(struct trace_iterator
*iter
)
1455 struct trace_seq
*s
= &iter
->seq
;
1457 if (!(trace_flags
& TRACE_ITER_ANNOTATE
))
1460 if (!(iter
->iter_flags
& TRACE_FILE_ANNOTATE
))
1463 if (cpumask_test_cpu(iter
->cpu
, iter
->started
))
1466 cpumask_set_cpu(iter
->cpu
, iter
->started
);
1467 trace_seq_printf(s
, "##### CPU %u buffer started ####\n", iter
->cpu
);
1470 static enum print_line_t
print_lat_fmt(struct trace_iterator
*iter
)
1472 struct trace_seq
*s
= &iter
->seq
;
1473 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1474 struct trace_event
*event
;
1475 struct trace_entry
*entry
= iter
->ent
;
1477 test_cpu_buff_start(iter
);
1479 event
= ftrace_find_event(entry
->type
);
1481 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1482 if (!trace_print_lat_context(iter
))
1487 return event
->latency_trace(iter
, sym_flags
);
1489 if (!trace_seq_printf(s
, "Unknown type %d\n", entry
->type
))
1492 return TRACE_TYPE_HANDLED
;
1494 return TRACE_TYPE_PARTIAL_LINE
;
1497 static enum print_line_t
print_trace_fmt(struct trace_iterator
*iter
)
1499 struct trace_seq
*s
= &iter
->seq
;
1500 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1501 struct trace_entry
*entry
;
1502 struct trace_event
*event
;
1506 test_cpu_buff_start(iter
);
1508 event
= ftrace_find_event(entry
->type
);
1510 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1511 if (!trace_print_context(iter
))
1516 return event
->trace(iter
, sym_flags
);
1518 if (!trace_seq_printf(s
, "Unknown type %d\n", entry
->type
))
1521 return TRACE_TYPE_HANDLED
;
1523 return TRACE_TYPE_PARTIAL_LINE
;
1526 static enum print_line_t
print_raw_fmt(struct trace_iterator
*iter
)
1528 struct trace_seq
*s
= &iter
->seq
;
1529 struct trace_entry
*entry
;
1530 struct trace_event
*event
;
1534 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1535 if (!trace_seq_printf(s
, "%d %d %llu ",
1536 entry
->pid
, iter
->cpu
, iter
->ts
))
1540 event
= ftrace_find_event(entry
->type
);
1542 return event
->raw(iter
, 0);
1544 if (!trace_seq_printf(s
, "%d ?\n", entry
->type
))
1547 return TRACE_TYPE_HANDLED
;
1549 return TRACE_TYPE_PARTIAL_LINE
;
1552 static enum print_line_t
print_hex_fmt(struct trace_iterator
*iter
)
1554 struct trace_seq
*s
= &iter
->seq
;
1555 unsigned char newline
= '\n';
1556 struct trace_entry
*entry
;
1557 struct trace_event
*event
;
1561 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1562 SEQ_PUT_HEX_FIELD_RET(s
, entry
->pid
);
1563 SEQ_PUT_HEX_FIELD_RET(s
, iter
->cpu
);
1564 SEQ_PUT_HEX_FIELD_RET(s
, iter
->ts
);
1567 event
= ftrace_find_event(entry
->type
);
1569 enum print_line_t ret
= event
->hex(iter
, 0);
1570 if (ret
!= TRACE_TYPE_HANDLED
)
1574 SEQ_PUT_FIELD_RET(s
, newline
);
1576 return TRACE_TYPE_HANDLED
;
1579 static enum print_line_t
print_printk_msg_only(struct trace_iterator
*iter
)
1581 struct trace_seq
*s
= &iter
->seq
;
1582 struct trace_entry
*entry
= iter
->ent
;
1583 struct print_entry
*field
;
1586 trace_assign_type(field
, entry
);
1588 ret
= trace_seq_printf(s
, "%s", field
->buf
);
1590 return TRACE_TYPE_PARTIAL_LINE
;
1592 return TRACE_TYPE_HANDLED
;
1595 static enum print_line_t
print_bin_fmt(struct trace_iterator
*iter
)
1597 struct trace_seq
*s
= &iter
->seq
;
1598 struct trace_entry
*entry
;
1599 struct trace_event
*event
;
1603 if (trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
1604 SEQ_PUT_FIELD_RET(s
, entry
->pid
);
1605 SEQ_PUT_FIELD_RET(s
, iter
->cpu
);
1606 SEQ_PUT_FIELD_RET(s
, iter
->ts
);
1609 event
= ftrace_find_event(entry
->type
);
1610 return event
? event
->binary(iter
, 0) : TRACE_TYPE_HANDLED
;
1613 static int trace_empty(struct trace_iterator
*iter
)
1617 for_each_tracing_cpu(cpu
) {
1618 if (iter
->buffer_iter
[cpu
]) {
1619 if (!ring_buffer_iter_empty(iter
->buffer_iter
[cpu
]))
1622 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
1630 static enum print_line_t
print_trace_line(struct trace_iterator
*iter
)
1632 enum print_line_t ret
;
1634 if (iter
->trace
&& iter
->trace
->print_line
) {
1635 ret
= iter
->trace
->print_line(iter
);
1636 if (ret
!= TRACE_TYPE_UNHANDLED
)
1640 if (iter
->ent
->type
== TRACE_PRINT
&&
1641 trace_flags
& TRACE_ITER_PRINTK
&&
1642 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
1643 return print_printk_msg_only(iter
);
1645 if (trace_flags
& TRACE_ITER_BIN
)
1646 return print_bin_fmt(iter
);
1648 if (trace_flags
& TRACE_ITER_HEX
)
1649 return print_hex_fmt(iter
);
1651 if (trace_flags
& TRACE_ITER_RAW
)
1652 return print_raw_fmt(iter
);
1654 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
)
1655 return print_lat_fmt(iter
);
1657 return print_trace_fmt(iter
);
1660 static int s_show(struct seq_file
*m
, void *v
)
1662 struct trace_iterator
*iter
= v
;
1664 if (iter
->ent
== NULL
) {
1666 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
1669 if (iter
->trace
&& iter
->trace
->print_header
)
1670 iter
->trace
->print_header(m
);
1671 else if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
1672 /* print nothing if the buffers are empty */
1673 if (trace_empty(iter
))
1675 print_trace_header(m
, iter
);
1676 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1677 print_lat_help_header(m
);
1679 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1680 print_func_help_header(m
);
1683 print_trace_line(iter
);
1684 trace_print_seq(m
, &iter
->seq
);
1690 static struct seq_operations tracer_seq_ops
= {
1697 static struct trace_iterator
*
1698 __tracing_open(struct inode
*inode
, struct file
*file
)
1700 long cpu_file
= (long) inode
->i_private
;
1701 void *fail_ret
= ERR_PTR(-ENOMEM
);
1702 struct trace_iterator
*iter
;
1706 if (tracing_disabled
)
1707 return ERR_PTR(-ENODEV
);
1709 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
1711 return ERR_PTR(-ENOMEM
);
1714 * We make a copy of the current tracer to avoid concurrent
1715 * changes on it while we are reading.
1717 mutex_lock(&trace_types_lock
);
1718 iter
->trace
= kzalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
1723 *iter
->trace
= *current_trace
;
1725 if (current_trace
&& current_trace
->print_max
)
1728 iter
->tr
= &global_trace
;
1730 mutex_init(&iter
->mutex
);
1731 iter
->cpu_file
= cpu_file
;
1733 /* Notify the tracer early; before we stop tracing. */
1734 if (iter
->trace
&& iter
->trace
->open
)
1735 iter
->trace
->open(iter
);
1737 /* Annotate start of buffers if we had overruns */
1738 if (ring_buffer_overruns(iter
->tr
->buffer
))
1739 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
1741 if (iter
->cpu_file
== TRACE_PIPE_ALL_CPU
) {
1742 for_each_tracing_cpu(cpu
) {
1744 iter
->buffer_iter
[cpu
] =
1745 ring_buffer_read_start(iter
->tr
->buffer
, cpu
);
1747 if (!iter
->buffer_iter
[cpu
])
1751 cpu
= iter
->cpu_file
;
1752 iter
->buffer_iter
[cpu
] =
1753 ring_buffer_read_start(iter
->tr
->buffer
, cpu
);
1755 if (!iter
->buffer_iter
[cpu
])
1759 /* TODO stop tracer */
1760 ret
= seq_open(file
, &tracer_seq_ops
);
1762 fail_ret
= ERR_PTR(ret
);
1766 m
= file
->private_data
;
1769 /* stop the trace while dumping */
1772 mutex_unlock(&trace_types_lock
);
1777 for_each_tracing_cpu(cpu
) {
1778 if (iter
->buffer_iter
[cpu
])
1779 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
1782 mutex_unlock(&trace_types_lock
);
1789 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
1791 if (tracing_disabled
)
1794 filp
->private_data
= inode
->i_private
;
1798 static int tracing_release(struct inode
*inode
, struct file
*file
)
1800 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
1801 struct trace_iterator
*iter
= m
->private;
1804 mutex_lock(&trace_types_lock
);
1805 for_each_tracing_cpu(cpu
) {
1806 if (iter
->buffer_iter
[cpu
])
1807 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
1810 if (iter
->trace
&& iter
->trace
->close
)
1811 iter
->trace
->close(iter
);
1813 /* reenable tracing if it was previously enabled */
1815 mutex_unlock(&trace_types_lock
);
1817 seq_release(inode
, file
);
1818 mutex_destroy(&iter
->mutex
);
1824 static int tracing_open(struct inode
*inode
, struct file
*file
)
1826 struct trace_iterator
*iter
;
1829 iter
= __tracing_open(inode
, file
);
1831 ret
= PTR_ERR(iter
);
1836 static int tracing_lt_open(struct inode
*inode
, struct file
*file
)
1838 struct trace_iterator
*iter
;
1841 iter
= __tracing_open(inode
, file
);
1844 ret
= PTR_ERR(iter
);
1846 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
1853 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1855 struct tracer
*t
= m
->private;
1867 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
1869 struct tracer
*t
= m
->private;
1872 mutex_lock(&trace_types_lock
);
1873 for (; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
1879 static void t_stop(struct seq_file
*m
, void *p
)
1881 mutex_unlock(&trace_types_lock
);
1884 static int t_show(struct seq_file
*m
, void *v
)
1886 struct tracer
*t
= v
;
1891 seq_printf(m
, "%s", t
->name
);
1900 static struct seq_operations show_traces_seq_ops
= {
1907 static int show_traces_open(struct inode
*inode
, struct file
*file
)
1911 if (tracing_disabled
)
1914 ret
= seq_open(file
, &show_traces_seq_ops
);
1916 struct seq_file
*m
= file
->private_data
;
1917 m
->private = trace_types
;
1923 static struct file_operations tracing_fops
= {
1924 .open
= tracing_open
,
1926 .llseek
= seq_lseek
,
1927 .release
= tracing_release
,
1930 static struct file_operations tracing_lt_fops
= {
1931 .open
= tracing_lt_open
,
1933 .llseek
= seq_lseek
,
1934 .release
= tracing_release
,
1937 static struct file_operations show_traces_fops
= {
1938 .open
= show_traces_open
,
1940 .release
= seq_release
,
1944 * Only trace on a CPU if the bitmask is set:
1946 static cpumask_var_t tracing_cpumask
;
1949 * The tracer itself will not take this lock, but still we want
1950 * to provide a consistent cpumask to user-space:
1952 static DEFINE_MUTEX(tracing_cpumask_update_lock
);
1955 * Temporary storage for the character representation of the
1956 * CPU bitmask (and one more byte for the newline):
1958 static char mask_str
[NR_CPUS
+ 1];
1961 tracing_cpumask_read(struct file
*filp
, char __user
*ubuf
,
1962 size_t count
, loff_t
*ppos
)
1966 mutex_lock(&tracing_cpumask_update_lock
);
1968 len
= cpumask_scnprintf(mask_str
, count
, tracing_cpumask
);
1969 if (count
- len
< 2) {
1973 len
+= sprintf(mask_str
+ len
, "\n");
1974 count
= simple_read_from_buffer(ubuf
, count
, ppos
, mask_str
, NR_CPUS
+1);
1977 mutex_unlock(&tracing_cpumask_update_lock
);
1983 tracing_cpumask_write(struct file
*filp
, const char __user
*ubuf
,
1984 size_t count
, loff_t
*ppos
)
1987 cpumask_var_t tracing_cpumask_new
;
1989 if (!alloc_cpumask_var(&tracing_cpumask_new
, GFP_KERNEL
))
1992 mutex_lock(&tracing_cpumask_update_lock
);
1993 err
= cpumask_parse_user(ubuf
, count
, tracing_cpumask_new
);
1997 local_irq_disable();
1998 __raw_spin_lock(&ftrace_max_lock
);
1999 for_each_tracing_cpu(cpu
) {
2001 * Increase/decrease the disabled counter if we are
2002 * about to flip a bit in the cpumask:
2004 if (cpumask_test_cpu(cpu
, tracing_cpumask
) &&
2005 !cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
2006 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
2008 if (!cpumask_test_cpu(cpu
, tracing_cpumask
) &&
2009 cpumask_test_cpu(cpu
, tracing_cpumask_new
)) {
2010 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
2013 __raw_spin_unlock(&ftrace_max_lock
);
2016 cpumask_copy(tracing_cpumask
, tracing_cpumask_new
);
2018 mutex_unlock(&tracing_cpumask_update_lock
);
2019 free_cpumask_var(tracing_cpumask_new
);
2024 mutex_unlock(&tracing_cpumask_update_lock
);
2025 free_cpumask_var(tracing_cpumask
);
2030 static struct file_operations tracing_cpumask_fops
= {
2031 .open
= tracing_open_generic
,
2032 .read
= tracing_cpumask_read
,
2033 .write
= tracing_cpumask_write
,
2037 tracing_trace_options_read(struct file
*filp
, char __user
*ubuf
,
2038 size_t cnt
, loff_t
*ppos
)
2040 struct tracer_opt
*trace_opts
;
2048 /* calculate max size */
2049 for (i
= 0; trace_options
[i
]; i
++) {
2050 len
+= strlen(trace_options
[i
]);
2051 len
+= 3; /* "no" and newline */
2054 mutex_lock(&trace_types_lock
);
2055 tracer_flags
= current_trace
->flags
->val
;
2056 trace_opts
= current_trace
->flags
->opts
;
2059 * Increase the size with names of options specific
2060 * of the current tracer.
2062 for (i
= 0; trace_opts
[i
].name
; i
++) {
2063 len
+= strlen(trace_opts
[i
].name
);
2064 len
+= 3; /* "no" and newline */
2067 /* +2 for \n and \0 */
2068 buf
= kmalloc(len
+ 2, GFP_KERNEL
);
2070 mutex_unlock(&trace_types_lock
);
2074 for (i
= 0; trace_options
[i
]; i
++) {
2075 if (trace_flags
& (1 << i
))
2076 r
+= sprintf(buf
+ r
, "%s\n", trace_options
[i
]);
2078 r
+= sprintf(buf
+ r
, "no%s\n", trace_options
[i
]);
2081 for (i
= 0; trace_opts
[i
].name
; i
++) {
2082 if (tracer_flags
& trace_opts
[i
].bit
)
2083 r
+= sprintf(buf
+ r
, "%s\n",
2084 trace_opts
[i
].name
);
2086 r
+= sprintf(buf
+ r
, "no%s\n",
2087 trace_opts
[i
].name
);
2089 mutex_unlock(&trace_types_lock
);
2091 WARN_ON(r
>= len
+ 2);
2093 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2099 /* Try to assign a tracer specific option */
2100 static int set_tracer_option(struct tracer
*trace
, char *cmp
, int neg
)
2102 struct tracer_flags
*trace_flags
= trace
->flags
;
2103 struct tracer_opt
*opts
= NULL
;
2107 for (i
= 0; trace_flags
->opts
[i
].name
; i
++) {
2108 opts
= &trace_flags
->opts
[i
];
2109 len
= strlen(opts
->name
);
2111 if (strncmp(cmp
, opts
->name
, len
) == 0) {
2112 ret
= trace
->set_flag(trace_flags
->val
,
2118 if (!trace_flags
->opts
[i
].name
)
2121 /* Refused to handle */
2126 trace_flags
->val
&= ~opts
->bit
;
2128 trace_flags
->val
|= opts
->bit
;
2134 tracing_trace_options_write(struct file
*filp
, const char __user
*ubuf
,
2135 size_t cnt
, loff_t
*ppos
)
2143 if (cnt
>= sizeof(buf
))
2146 if (copy_from_user(&buf
, ubuf
, cnt
))
2151 if (strncmp(buf
, "no", 2) == 0) {
2156 for (i
= 0; trace_options
[i
]; i
++) {
2157 int len
= strlen(trace_options
[i
]);
2159 if (strncmp(cmp
, trace_options
[i
], len
) == 0) {
2161 trace_flags
&= ~(1 << i
);
2163 trace_flags
|= (1 << i
);
2168 /* If no option could be set, test the specific tracer options */
2169 if (!trace_options
[i
]) {
2170 mutex_lock(&trace_types_lock
);
2171 ret
= set_tracer_option(current_trace
, cmp
, neg
);
2172 mutex_unlock(&trace_types_lock
);
2182 static struct file_operations tracing_iter_fops
= {
2183 .open
= tracing_open_generic
,
2184 .read
= tracing_trace_options_read
,
2185 .write
= tracing_trace_options_write
,
2188 static const char readme_msg
[] =
2189 "tracing mini-HOWTO:\n\n"
2191 "# mount -t debugfs nodev /debug\n\n"
2192 "# cat /debug/tracing/available_tracers\n"
2193 "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
2194 "# cat /debug/tracing/current_tracer\n"
2196 "# echo sched_switch > /debug/tracing/current_tracer\n"
2197 "# cat /debug/tracing/current_tracer\n"
2199 "# cat /debug/tracing/trace_options\n"
2200 "noprint-parent nosym-offset nosym-addr noverbose\n"
2201 "# echo print-parent > /debug/tracing/trace_options\n"
2202 "# echo 1 > /debug/tracing/tracing_enabled\n"
2203 "# cat /debug/tracing/trace > /tmp/trace.txt\n"
2204 "echo 0 > /debug/tracing/tracing_enabled\n"
2208 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
2209 size_t cnt
, loff_t
*ppos
)
2211 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
2212 readme_msg
, strlen(readme_msg
));
2215 static struct file_operations tracing_readme_fops
= {
2216 .open
= tracing_open_generic
,
2217 .read
= tracing_readme_read
,
2221 tracing_ctrl_read(struct file
*filp
, char __user
*ubuf
,
2222 size_t cnt
, loff_t
*ppos
)
2227 r
= sprintf(buf
, "%u\n", tracer_enabled
);
2228 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2232 tracing_ctrl_write(struct file
*filp
, const char __user
*ubuf
,
2233 size_t cnt
, loff_t
*ppos
)
2235 struct trace_array
*tr
= filp
->private_data
;
2240 if (cnt
>= sizeof(buf
))
2243 if (copy_from_user(&buf
, ubuf
, cnt
))
2248 ret
= strict_strtoul(buf
, 10, &val
);
2254 mutex_lock(&trace_types_lock
);
2255 if (tracer_enabled
^ val
) {
2258 if (current_trace
->start
)
2259 current_trace
->start(tr
);
2264 if (current_trace
->stop
)
2265 current_trace
->stop(tr
);
2268 mutex_unlock(&trace_types_lock
);
2276 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
2277 size_t cnt
, loff_t
*ppos
)
2279 char buf
[max_tracer_type_len
+2];
2282 mutex_lock(&trace_types_lock
);
2284 r
= sprintf(buf
, "%s\n", current_trace
->name
);
2286 r
= sprintf(buf
, "\n");
2287 mutex_unlock(&trace_types_lock
);
2289 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2292 int tracer_init(struct tracer
*t
, struct trace_array
*tr
)
2294 tracing_reset_online_cpus(tr
);
2298 struct trace_option_dentry
;
2300 static struct trace_option_dentry
*
2301 create_trace_option_files(struct tracer
*tracer
);
2304 destroy_trace_option_files(struct trace_option_dentry
*topts
);
2306 static int tracing_set_tracer(const char *buf
)
2308 static struct trace_option_dentry
*topts
;
2309 struct trace_array
*tr
= &global_trace
;
2313 mutex_lock(&trace_types_lock
);
2314 for (t
= trace_types
; t
; t
= t
->next
) {
2315 if (strcmp(t
->name
, buf
) == 0)
2322 if (t
== current_trace
)
2325 trace_branch_disable();
2326 if (current_trace
&& current_trace
->reset
)
2327 current_trace
->reset(tr
);
2329 destroy_trace_option_files(topts
);
2333 topts
= create_trace_option_files(current_trace
);
2336 ret
= tracer_init(t
, tr
);
2341 trace_branch_enable(tr
);
2343 mutex_unlock(&trace_types_lock
);
2349 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
2350 size_t cnt
, loff_t
*ppos
)
2352 char buf
[max_tracer_type_len
+1];
2359 if (cnt
> max_tracer_type_len
)
2360 cnt
= max_tracer_type_len
;
2362 if (copy_from_user(&buf
, ubuf
, cnt
))
2367 /* strip ending whitespace. */
2368 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
2371 err
= tracing_set_tracer(buf
);
2381 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
2382 size_t cnt
, loff_t
*ppos
)
2384 unsigned long *ptr
= filp
->private_data
;
2388 r
= snprintf(buf
, sizeof(buf
), "%ld\n",
2389 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
2390 if (r
> sizeof(buf
))
2392 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2396 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
2397 size_t cnt
, loff_t
*ppos
)
2399 unsigned long *ptr
= filp
->private_data
;
2404 if (cnt
>= sizeof(buf
))
2407 if (copy_from_user(&buf
, ubuf
, cnt
))
2412 ret
= strict_strtoul(buf
, 10, &val
);
2421 static int tracing_open_pipe(struct inode
*inode
, struct file
*filp
)
2423 long cpu_file
= (long) inode
->i_private
;
2424 struct trace_iterator
*iter
;
2427 if (tracing_disabled
)
2430 mutex_lock(&trace_types_lock
);
2432 /* We only allow one reader per cpu */
2433 if (cpu_file
== TRACE_PIPE_ALL_CPU
) {
2434 if (!cpumask_empty(tracing_reader_cpumask
)) {
2438 cpumask_setall(tracing_reader_cpumask
);
2440 if (!cpumask_test_cpu(cpu_file
, tracing_reader_cpumask
))
2441 cpumask_set_cpu(cpu_file
, tracing_reader_cpumask
);
2448 /* create a buffer to store the information to pass to userspace */
2449 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2456 * We make a copy of the current tracer to avoid concurrent
2457 * changes on it while we are reading.
2459 iter
->trace
= kmalloc(sizeof(*iter
->trace
), GFP_KERNEL
);
2465 *iter
->trace
= *current_trace
;
2467 if (!alloc_cpumask_var(&iter
->started
, GFP_KERNEL
)) {
2472 /* trace pipe does not show start of buffer */
2473 cpumask_setall(iter
->started
);
2475 iter
->cpu_file
= cpu_file
;
2476 iter
->tr
= &global_trace
;
2477 mutex_init(&iter
->mutex
);
2478 filp
->private_data
= iter
;
2480 if (iter
->trace
->pipe_open
)
2481 iter
->trace
->pipe_open(iter
);
2484 mutex_unlock(&trace_types_lock
);
2490 mutex_unlock(&trace_types_lock
);
2494 static int tracing_release_pipe(struct inode
*inode
, struct file
*file
)
2496 struct trace_iterator
*iter
= file
->private_data
;
2498 mutex_lock(&trace_types_lock
);
2500 if (iter
->cpu_file
== TRACE_PIPE_ALL_CPU
)
2501 cpumask_clear(tracing_reader_cpumask
);
2503 cpumask_clear_cpu(iter
->cpu_file
, tracing_reader_cpumask
);
2505 mutex_unlock(&trace_types_lock
);
2507 free_cpumask_var(iter
->started
);
2508 mutex_destroy(&iter
->mutex
);
2516 tracing_poll_pipe(struct file
*filp
, poll_table
*poll_table
)
2518 struct trace_iterator
*iter
= filp
->private_data
;
2520 if (trace_flags
& TRACE_ITER_BLOCK
) {
2522 * Always select as readable when in blocking mode
2524 return POLLIN
| POLLRDNORM
;
2526 if (!trace_empty(iter
))
2527 return POLLIN
| POLLRDNORM
;
2528 poll_wait(filp
, &trace_wait
, poll_table
);
2529 if (!trace_empty(iter
))
2530 return POLLIN
| POLLRDNORM
;
2537 void default_wait_pipe(struct trace_iterator
*iter
)
2541 prepare_to_wait(&trace_wait
, &wait
, TASK_INTERRUPTIBLE
);
2543 if (trace_empty(iter
))
2546 finish_wait(&trace_wait
, &wait
);
2550 * This is a make-shift waitqueue.
2551 * A tracer might use this callback on some rare cases:
2553 * 1) the current tracer might hold the runqueue lock when it wakes up
2554 * a reader, hence a deadlock (sched, function, and function graph tracers)
2555 * 2) the function tracers, trace all functions, we don't want
2556 * the overhead of calling wake_up and friends
2557 * (and tracing them too)
2559 * Anyway, this is really very primitive wakeup.
2561 void poll_wait_pipe(struct trace_iterator
*iter
)
2563 set_current_state(TASK_INTERRUPTIBLE
);
2564 /* sleep for 100 msecs, and try again. */
2565 schedule_timeout(HZ
/ 10);
2568 /* Must be called with trace_types_lock mutex held. */
2569 static int tracing_wait_pipe(struct file
*filp
)
2571 struct trace_iterator
*iter
= filp
->private_data
;
2573 while (trace_empty(iter
)) {
2575 if ((filp
->f_flags
& O_NONBLOCK
)) {
2579 mutex_unlock(&iter
->mutex
);
2581 iter
->trace
->wait_pipe(iter
);
2583 mutex_lock(&iter
->mutex
);
2585 if (signal_pending(current
))
2589 * We block until we read something and tracing is disabled.
2590 * We still block if tracing is disabled, but we have never
2591 * read anything. This allows a user to cat this file, and
2592 * then enable tracing. But after we have read something,
2593 * we give an EOF when tracing is again disabled.
2595 * iter->pos will be 0 if we haven't read anything.
2597 if (!tracer_enabled
&& iter
->pos
)
2608 tracing_read_pipe(struct file
*filp
, char __user
*ubuf
,
2609 size_t cnt
, loff_t
*ppos
)
2611 struct trace_iterator
*iter
= filp
->private_data
;
2612 static struct tracer
*old_tracer
;
2615 /* return any leftover data */
2616 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
2620 trace_seq_init(&iter
->seq
);
2622 /* copy the tracer to avoid using a global lock all around */
2623 mutex_lock(&trace_types_lock
);
2624 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
2625 old_tracer
= current_trace
;
2626 *iter
->trace
= *current_trace
;
2628 mutex_unlock(&trace_types_lock
);
2631 * Avoid more than one consumer on a single file descriptor
2632 * This is just a matter of traces coherency, the ring buffer itself
2635 mutex_lock(&iter
->mutex
);
2636 if (iter
->trace
->read
) {
2637 sret
= iter
->trace
->read(iter
, filp
, ubuf
, cnt
, ppos
);
2643 sret
= tracing_wait_pipe(filp
);
2647 /* stop when tracing is finished */
2648 if (trace_empty(iter
)) {
2653 if (cnt
>= PAGE_SIZE
)
2654 cnt
= PAGE_SIZE
- 1;
2656 /* reset all but tr, trace, and overruns */
2657 memset(&iter
->seq
, 0,
2658 sizeof(struct trace_iterator
) -
2659 offsetof(struct trace_iterator
, seq
));
2662 while (find_next_entry_inc(iter
) != NULL
) {
2663 enum print_line_t ret
;
2664 int len
= iter
->seq
.len
;
2666 ret
= print_trace_line(iter
);
2667 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
2668 /* don't print partial lines */
2669 iter
->seq
.len
= len
;
2672 if (ret
!= TRACE_TYPE_NO_CONSUME
)
2673 trace_consume(iter
);
2675 if (iter
->seq
.len
>= cnt
)
2679 /* Now copy what we have to the user */
2680 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
2681 if (iter
->seq
.readpos
>= iter
->seq
.len
)
2682 trace_seq_init(&iter
->seq
);
2685 * If there was nothing to send to user, inspite of consuming trace
2686 * entries, go back to wait for more entries.
2692 mutex_unlock(&iter
->mutex
);
2697 static void tracing_pipe_buf_release(struct pipe_inode_info
*pipe
,
2698 struct pipe_buffer
*buf
)
2700 __free_page(buf
->page
);
2703 static void tracing_spd_release_pipe(struct splice_pipe_desc
*spd
,
2706 __free_page(spd
->pages
[idx
]);
2709 static struct pipe_buf_operations tracing_pipe_buf_ops
= {
2711 .map
= generic_pipe_buf_map
,
2712 .unmap
= generic_pipe_buf_unmap
,
2713 .confirm
= generic_pipe_buf_confirm
,
2714 .release
= tracing_pipe_buf_release
,
2715 .steal
= generic_pipe_buf_steal
,
2716 .get
= generic_pipe_buf_get
,
2720 tracing_fill_pipe_page(size_t rem
, struct trace_iterator
*iter
)
2725 /* Seq buffer is page-sized, exactly what we need. */
2727 count
= iter
->seq
.len
;
2728 ret
= print_trace_line(iter
);
2729 count
= iter
->seq
.len
- count
;
2732 iter
->seq
.len
-= count
;
2735 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
2736 iter
->seq
.len
-= count
;
2740 trace_consume(iter
);
2742 if (!find_next_entry_inc(iter
)) {
2752 static ssize_t
tracing_splice_read_pipe(struct file
*filp
,
2754 struct pipe_inode_info
*pipe
,
2758 struct page
*pages
[PIPE_BUFFERS
];
2759 struct partial_page partial
[PIPE_BUFFERS
];
2760 struct trace_iterator
*iter
= filp
->private_data
;
2761 struct splice_pipe_desc spd
= {
2764 .nr_pages
= 0, /* This gets updated below. */
2766 .ops
= &tracing_pipe_buf_ops
,
2767 .spd_release
= tracing_spd_release_pipe
,
2769 static struct tracer
*old_tracer
;
2774 /* copy the tracer to avoid using a global lock all around */
2775 mutex_lock(&trace_types_lock
);
2776 if (unlikely(old_tracer
!= current_trace
&& current_trace
)) {
2777 old_tracer
= current_trace
;
2778 *iter
->trace
= *current_trace
;
2780 mutex_unlock(&trace_types_lock
);
2782 mutex_lock(&iter
->mutex
);
2784 if (iter
->trace
->splice_read
) {
2785 ret
= iter
->trace
->splice_read(iter
, filp
,
2786 ppos
, pipe
, len
, flags
);
2791 ret
= tracing_wait_pipe(filp
);
2795 if (!iter
->ent
&& !find_next_entry_inc(iter
)) {
2800 /* Fill as many pages as possible. */
2801 for (i
= 0, rem
= len
; i
< PIPE_BUFFERS
&& rem
; i
++) {
2802 pages
[i
] = alloc_page(GFP_KERNEL
);
2806 rem
= tracing_fill_pipe_page(rem
, iter
);
2808 /* Copy the data into the page, so we can start over. */
2809 ret
= trace_seq_to_buffer(&iter
->seq
,
2810 page_address(pages
[i
]),
2813 __free_page(pages
[i
]);
2816 partial
[i
].offset
= 0;
2817 partial
[i
].len
= iter
->seq
.len
;
2819 trace_seq_init(&iter
->seq
);
2822 mutex_unlock(&iter
->mutex
);
2826 return splice_to_pipe(pipe
, &spd
);
2829 mutex_unlock(&iter
->mutex
);
2835 tracing_entries_read(struct file
*filp
, char __user
*ubuf
,
2836 size_t cnt
, loff_t
*ppos
)
2838 struct trace_array
*tr
= filp
->private_data
;
2842 r
= sprintf(buf
, "%lu\n", tr
->entries
>> 10);
2843 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2847 tracing_entries_write(struct file
*filp
, const char __user
*ubuf
,
2848 size_t cnt
, loff_t
*ppos
)
2854 if (cnt
>= sizeof(buf
))
2857 if (copy_from_user(&buf
, ubuf
, cnt
))
2862 ret
= strict_strtoul(buf
, 10, &val
);
2866 /* must have at least 1 entry */
2870 mutex_lock(&trace_types_lock
);
2874 /* disable all cpu buffers */
2875 for_each_tracing_cpu(cpu
) {
2876 if (global_trace
.data
[cpu
])
2877 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
2878 if (max_tr
.data
[cpu
])
2879 atomic_inc(&max_tr
.data
[cpu
]->disabled
);
2882 /* value is in KB */
2885 if (val
!= global_trace
.entries
) {
2886 ret
= ring_buffer_resize(global_trace
.buffer
, val
);
2892 ret
= ring_buffer_resize(max_tr
.buffer
, val
);
2896 r
= ring_buffer_resize(global_trace
.buffer
,
2897 global_trace
.entries
);
2899 /* AARGH! We are left with different
2900 * size max buffer!!!! */
2902 tracing_disabled
= 1;
2907 global_trace
.entries
= val
;
2912 /* If check pages failed, return ENOMEM */
2913 if (tracing_disabled
)
2916 for_each_tracing_cpu(cpu
) {
2917 if (global_trace
.data
[cpu
])
2918 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
2919 if (max_tr
.data
[cpu
])
2920 atomic_dec(&max_tr
.data
[cpu
]->disabled
);
2924 max_tr
.entries
= global_trace
.entries
;
2925 mutex_unlock(&trace_types_lock
);
2930 static int mark_printk(const char *fmt
, ...)
2934 va_start(args
, fmt
);
2935 ret
= trace_vprintk(0, -1, fmt
, args
);
2941 tracing_mark_write(struct file
*filp
, const char __user
*ubuf
,
2942 size_t cnt
, loff_t
*fpos
)
2947 if (tracing_disabled
)
2950 if (cnt
> TRACE_BUF_SIZE
)
2951 cnt
= TRACE_BUF_SIZE
;
2953 buf
= kmalloc(cnt
+ 1, GFP_KERNEL
);
2957 if (copy_from_user(buf
, ubuf
, cnt
)) {
2962 /* Cut from the first nil or newline. */
2964 end
= strchr(buf
, '\n');
2968 cnt
= mark_printk("%s\n", buf
);
2975 static struct file_operations tracing_max_lat_fops
= {
2976 .open
= tracing_open_generic
,
2977 .read
= tracing_max_lat_read
,
2978 .write
= tracing_max_lat_write
,
2981 static struct file_operations tracing_ctrl_fops
= {
2982 .open
= tracing_open_generic
,
2983 .read
= tracing_ctrl_read
,
2984 .write
= tracing_ctrl_write
,
2987 static struct file_operations set_tracer_fops
= {
2988 .open
= tracing_open_generic
,
2989 .read
= tracing_set_trace_read
,
2990 .write
= tracing_set_trace_write
,
2993 static struct file_operations tracing_pipe_fops
= {
2994 .open
= tracing_open_pipe
,
2995 .poll
= tracing_poll_pipe
,
2996 .read
= tracing_read_pipe
,
2997 .splice_read
= tracing_splice_read_pipe
,
2998 .release
= tracing_release_pipe
,
3001 static struct file_operations tracing_entries_fops
= {
3002 .open
= tracing_open_generic
,
3003 .read
= tracing_entries_read
,
3004 .write
= tracing_entries_write
,
3007 static struct file_operations tracing_mark_fops
= {
3008 .open
= tracing_open_generic
,
3009 .write
= tracing_mark_write
,
3012 struct ftrace_buffer_info
{
3013 struct trace_array
*tr
;
3019 static int tracing_buffers_open(struct inode
*inode
, struct file
*filp
)
3021 int cpu
= (int)(long)inode
->i_private
;
3022 struct ftrace_buffer_info
*info
;
3024 if (tracing_disabled
)
3027 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
3031 info
->tr
= &global_trace
;
3033 info
->spare
= ring_buffer_alloc_read_page(info
->tr
->buffer
);
3034 /* Force reading ring buffer for first read */
3035 info
->read
= (unsigned int)-1;
3039 filp
->private_data
= info
;
3049 tracing_buffers_read(struct file
*filp
, char __user
*ubuf
,
3050 size_t count
, loff_t
*ppos
)
3052 struct ftrace_buffer_info
*info
= filp
->private_data
;
3060 /* Do we have previous read data to read? */
3061 if (info
->read
< PAGE_SIZE
)
3066 ret
= ring_buffer_read_page(info
->tr
->buffer
,
3073 pos
= ring_buffer_page_len(info
->spare
);
3075 if (pos
< PAGE_SIZE
)
3076 memset(info
->spare
+ pos
, 0, PAGE_SIZE
- pos
);
3079 size
= PAGE_SIZE
- info
->read
;
3083 ret
= copy_to_user(ubuf
, info
->spare
+ info
->read
, size
);
3094 static int tracing_buffers_release(struct inode
*inode
, struct file
*file
)
3096 struct ftrace_buffer_info
*info
= file
->private_data
;
3098 ring_buffer_free_read_page(info
->tr
->buffer
, info
->spare
);
3105 struct ring_buffer
*buffer
;
3110 static void buffer_pipe_buf_release(struct pipe_inode_info
*pipe
,
3111 struct pipe_buffer
*buf
)
3113 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
3118 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
3123 static int buffer_pipe_buf_steal(struct pipe_inode_info
*pipe
,
3124 struct pipe_buffer
*buf
)
3129 static void buffer_pipe_buf_get(struct pipe_inode_info
*pipe
,
3130 struct pipe_buffer
*buf
)
3132 struct buffer_ref
*ref
= (struct buffer_ref
*)buf
->private;
3137 /* Pipe buffer operations for a buffer. */
3138 static struct pipe_buf_operations buffer_pipe_buf_ops
= {
3140 .map
= generic_pipe_buf_map
,
3141 .unmap
= generic_pipe_buf_unmap
,
3142 .confirm
= generic_pipe_buf_confirm
,
3143 .release
= buffer_pipe_buf_release
,
3144 .steal
= buffer_pipe_buf_steal
,
3145 .get
= buffer_pipe_buf_get
,
3149 * Callback from splice_to_pipe(), if we need to release some pages
3150 * at the end of the spd in case we error'ed out in filling the pipe.
3152 static void buffer_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
3154 struct buffer_ref
*ref
=
3155 (struct buffer_ref
*)spd
->partial
[i
].private;
3160 ring_buffer_free_read_page(ref
->buffer
, ref
->page
);
3162 spd
->partial
[i
].private = 0;
3166 tracing_buffers_splice_read(struct file
*file
, loff_t
*ppos
,
3167 struct pipe_inode_info
*pipe
, size_t len
,
3170 struct ftrace_buffer_info
*info
= file
->private_data
;
3171 struct partial_page partial
[PIPE_BUFFERS
];
3172 struct page
*pages
[PIPE_BUFFERS
];
3173 struct splice_pipe_desc spd
= {
3177 .ops
= &buffer_pipe_buf_ops
,
3178 .spd_release
= buffer_spd_release
,
3180 struct buffer_ref
*ref
;
3185 * We can't seek on a buffer input
3187 if (unlikely(*ppos
))
3191 for (i
= 0; i
< PIPE_BUFFERS
&& len
; i
++, len
-= size
) {
3195 ref
= kzalloc(sizeof(*ref
), GFP_KERNEL
);
3199 ref
->buffer
= info
->tr
->buffer
;
3200 ref
->page
= ring_buffer_alloc_read_page(ref
->buffer
);
3206 r
= ring_buffer_read_page(ref
->buffer
, &ref
->page
,
3209 ring_buffer_free_read_page(ref
->buffer
,
3216 * zero out any left over data, this is going to
3219 size
= ring_buffer_page_len(ref
->page
);
3220 if (size
< PAGE_SIZE
)
3221 memset(ref
->page
+ size
, 0, PAGE_SIZE
- size
);
3223 page
= virt_to_page(ref
->page
);
3225 spd
.pages
[i
] = page
;
3226 spd
.partial
[i
].len
= PAGE_SIZE
;
3227 spd
.partial
[i
].offset
= 0;
3228 spd
.partial
[i
].private = (unsigned long)ref
;
3234 /* did we read anything? */
3235 if (!spd
.nr_pages
) {
3236 if (flags
& SPLICE_F_NONBLOCK
)
3244 ret
= splice_to_pipe(pipe
, &spd
);
3249 static const struct file_operations tracing_buffers_fops
= {
3250 .open
= tracing_buffers_open
,
3251 .read
= tracing_buffers_read
,
3252 .release
= tracing_buffers_release
,
3253 .splice_read
= tracing_buffers_splice_read
,
3254 .llseek
= no_llseek
,
3257 #ifdef CONFIG_DYNAMIC_FTRACE
3259 int __weak
ftrace_arch_read_dyn_info(char *buf
, int size
)
3265 tracing_read_dyn_info(struct file
*filp
, char __user
*ubuf
,
3266 size_t cnt
, loff_t
*ppos
)
3268 static char ftrace_dyn_info_buffer
[1024];
3269 static DEFINE_MUTEX(dyn_info_mutex
);
3270 unsigned long *p
= filp
->private_data
;
3271 char *buf
= ftrace_dyn_info_buffer
;
3272 int size
= ARRAY_SIZE(ftrace_dyn_info_buffer
);
3275 mutex_lock(&dyn_info_mutex
);
3276 r
= sprintf(buf
, "%ld ", *p
);
3278 r
+= ftrace_arch_read_dyn_info(buf
+r
, (size
-1)-r
);
3281 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
3283 mutex_unlock(&dyn_info_mutex
);
3288 static struct file_operations tracing_dyn_info_fops
= {
3289 .open
= tracing_open_generic
,
3290 .read
= tracing_read_dyn_info
,
3294 static struct dentry
*d_tracer
;
3296 struct dentry
*tracing_init_dentry(void)
3303 d_tracer
= debugfs_create_dir("tracing", NULL
);
3305 if (!d_tracer
&& !once
) {
3307 pr_warning("Could not create debugfs directory 'tracing'\n");
3314 static struct dentry
*d_percpu
;
3316 struct dentry
*tracing_dentry_percpu(void)
3319 struct dentry
*d_tracer
;
3324 d_tracer
= tracing_init_dentry();
3329 d_percpu
= debugfs_create_dir("per_cpu", d_tracer
);
3331 if (!d_percpu
&& !once
) {
3333 pr_warning("Could not create debugfs directory 'per_cpu'\n");
3340 static void tracing_init_debugfs_percpu(long cpu
)
3342 struct dentry
*d_percpu
= tracing_dentry_percpu();
3343 struct dentry
*entry
, *d_cpu
;
3344 /* strlen(cpu) + MAX(log10(cpu)) + '\0' */
3347 if (cpu
> 999 || cpu
< 0)
3350 sprintf(cpu_dir
, "cpu%ld", cpu
);
3351 d_cpu
= debugfs_create_dir(cpu_dir
, d_percpu
);
3353 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir
);
3357 /* per cpu trace_pipe */
3358 entry
= debugfs_create_file("trace_pipe", 0444, d_cpu
,
3359 (void *) cpu
, &tracing_pipe_fops
);
3361 pr_warning("Could not create debugfs 'trace_pipe' entry\n");
3364 entry
= debugfs_create_file("trace", 0444, d_cpu
,
3365 (void *) cpu
, &tracing_fops
);
3367 pr_warning("Could not create debugfs 'trace' entry\n");
3370 #ifdef CONFIG_FTRACE_SELFTEST
3371 /* Let selftest have access to static functions in this file */
3372 #include "trace_selftest.c"
3375 struct trace_option_dentry
{
3376 struct tracer_opt
*opt
;
3377 struct tracer_flags
*flags
;
3378 struct dentry
*entry
;
3382 trace_options_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
3385 struct trace_option_dentry
*topt
= filp
->private_data
;
3388 if (topt
->flags
->val
& topt
->opt
->bit
)
3393 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
3397 trace_options_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
3400 struct trace_option_dentry
*topt
= filp
->private_data
;
3405 if (cnt
>= sizeof(buf
))
3408 if (copy_from_user(&buf
, ubuf
, cnt
))
3413 ret
= strict_strtoul(buf
, 10, &val
);
3420 /* do nothing if already cleared */
3421 if (!(topt
->flags
->val
& topt
->opt
->bit
))
3424 mutex_lock(&trace_types_lock
);
3425 if (current_trace
->set_flag
)
3426 ret
= current_trace
->set_flag(topt
->flags
->val
,
3428 mutex_unlock(&trace_types_lock
);
3431 topt
->flags
->val
&= ~topt
->opt
->bit
;
3434 /* do nothing if already set */
3435 if (topt
->flags
->val
& topt
->opt
->bit
)
3438 mutex_lock(&trace_types_lock
);
3439 if (current_trace
->set_flag
)
3440 ret
= current_trace
->set_flag(topt
->flags
->val
,
3442 mutex_unlock(&trace_types_lock
);
3445 topt
->flags
->val
|= topt
->opt
->bit
;
3458 static const struct file_operations trace_options_fops
= {
3459 .open
= tracing_open_generic
,
3460 .read
= trace_options_read
,
3461 .write
= trace_options_write
,
3465 trace_options_core_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
3468 long index
= (long)filp
->private_data
;
3471 if (trace_flags
& (1 << index
))
3476 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, 2);
3480 trace_options_core_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
3483 long index
= (long)filp
->private_data
;
3488 if (cnt
>= sizeof(buf
))
3491 if (copy_from_user(&buf
, ubuf
, cnt
))
3496 ret
= strict_strtoul(buf
, 10, &val
);
3502 trace_flags
&= ~(1 << index
);
3505 trace_flags
|= 1 << index
;
3517 static const struct file_operations trace_options_core_fops
= {
3518 .open
= tracing_open_generic
,
3519 .read
= trace_options_core_read
,
3520 .write
= trace_options_core_write
,
3523 static struct dentry
*trace_options_init_dentry(void)
3525 struct dentry
*d_tracer
;
3526 static struct dentry
*t_options
;
3531 d_tracer
= tracing_init_dentry();
3535 t_options
= debugfs_create_dir("options", d_tracer
);
3537 pr_warning("Could not create debugfs directory 'options'\n");
3545 create_trace_option_file(struct trace_option_dentry
*topt
,
3546 struct tracer_flags
*flags
,
3547 struct tracer_opt
*opt
)
3549 struct dentry
*t_options
;
3550 struct dentry
*entry
;
3552 t_options
= trace_options_init_dentry();
3556 topt
->flags
= flags
;
3559 entry
= debugfs_create_file(opt
->name
, 0644, t_options
, topt
,
3560 &trace_options_fops
);
3562 topt
->entry
= entry
;
3566 static struct trace_option_dentry
*
3567 create_trace_option_files(struct tracer
*tracer
)
3569 struct trace_option_dentry
*topts
;
3570 struct tracer_flags
*flags
;
3571 struct tracer_opt
*opts
;
3577 flags
= tracer
->flags
;
3579 if (!flags
|| !flags
->opts
)
3584 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
3587 topts
= kcalloc(cnt
+ 1, sizeof(*topts
), GFP_KERNEL
);
3591 for (cnt
= 0; opts
[cnt
].name
; cnt
++)
3592 create_trace_option_file(&topts
[cnt
], flags
,
3599 destroy_trace_option_files(struct trace_option_dentry
*topts
)
3606 for (cnt
= 0; topts
[cnt
].opt
; cnt
++) {
3607 if (topts
[cnt
].entry
)
3608 debugfs_remove(topts
[cnt
].entry
);
3614 static struct dentry
*
3615 create_trace_option_core_file(const char *option
, long index
)
3617 struct dentry
*t_options
;
3618 struct dentry
*entry
;
3620 t_options
= trace_options_init_dentry();
3624 entry
= debugfs_create_file(option
, 0644, t_options
, (void *)index
,
3625 &trace_options_core_fops
);
3630 static __init
void create_trace_options_dir(void)
3632 struct dentry
*t_options
;
3633 struct dentry
*entry
;
3636 t_options
= trace_options_init_dentry();
3640 for (i
= 0; trace_options
[i
]; i
++) {
3641 entry
= create_trace_option_core_file(trace_options
[i
], i
);
3643 pr_warning("Could not create debugfs %s entry\n",
3648 static __init
int tracer_init_debugfs(void)
3650 struct dentry
*d_tracer
;
3651 struct dentry
*buffers
;
3652 struct dentry
*entry
;
3655 d_tracer
= tracing_init_dentry();
3657 entry
= debugfs_create_file("tracing_enabled", 0644, d_tracer
,
3658 &global_trace
, &tracing_ctrl_fops
);
3660 pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
3662 entry
= debugfs_create_file("trace_options", 0644, d_tracer
,
3663 NULL
, &tracing_iter_fops
);
3665 pr_warning("Could not create debugfs 'trace_options' entry\n");
3667 create_trace_options_dir();
3669 entry
= debugfs_create_file("tracing_cpumask", 0644, d_tracer
,
3670 NULL
, &tracing_cpumask_fops
);
3672 pr_warning("Could not create debugfs 'tracing_cpumask' entry\n");
3674 entry
= debugfs_create_file("trace", 0444, d_tracer
,
3675 (void *) TRACE_PIPE_ALL_CPU
, &tracing_fops
);
3677 pr_warning("Could not create debugfs 'trace' entry\n");
3679 entry
= debugfs_create_file("available_tracers", 0444, d_tracer
,
3680 &global_trace
, &show_traces_fops
);
3682 pr_warning("Could not create debugfs 'available_tracers' entry\n");
3684 entry
= debugfs_create_file("current_tracer", 0444, d_tracer
,
3685 &global_trace
, &set_tracer_fops
);
3687 pr_warning("Could not create debugfs 'current_tracer' entry\n");
3689 entry
= debugfs_create_file("tracing_max_latency", 0644, d_tracer
,
3690 &tracing_max_latency
,
3691 &tracing_max_lat_fops
);
3693 pr_warning("Could not create debugfs "
3694 "'tracing_max_latency' entry\n");
3696 entry
= debugfs_create_file("tracing_thresh", 0644, d_tracer
,
3697 &tracing_thresh
, &tracing_max_lat_fops
);
3699 pr_warning("Could not create debugfs "
3700 "'tracing_thresh' entry\n");
3701 entry
= debugfs_create_file("README", 0644, d_tracer
,
3702 NULL
, &tracing_readme_fops
);
3704 pr_warning("Could not create debugfs 'README' entry\n");
3706 entry
= debugfs_create_file("trace_pipe", 0444, d_tracer
,
3707 (void *) TRACE_PIPE_ALL_CPU
, &tracing_pipe_fops
);
3709 pr_warning("Could not create debugfs "
3710 "'trace_pipe' entry\n");
3712 entry
= debugfs_create_file("buffer_size_kb", 0644, d_tracer
,
3713 &global_trace
, &tracing_entries_fops
);
3715 pr_warning("Could not create debugfs "
3716 "'buffer_size_kb' entry\n");
3718 entry
= debugfs_create_file("trace_marker", 0220, d_tracer
,
3719 NULL
, &tracing_mark_fops
);
3721 pr_warning("Could not create debugfs "
3722 "'trace_marker' entry\n");
3724 buffers
= debugfs_create_dir("binary_buffers", d_tracer
);
3727 pr_warning("Could not create buffers directory\n");
3732 for_each_tracing_cpu(cpu
) {
3733 sprintf(buf
, "%d", cpu
);
3735 entry
= debugfs_create_file(buf
, 0444, buffers
,
3737 &tracing_buffers_fops
);
3739 pr_warning("Could not create debugfs buffers "
3740 "'%s' entry\n", buf
);
3744 #ifdef CONFIG_DYNAMIC_FTRACE
3745 entry
= debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
3746 &ftrace_update_tot_cnt
,
3747 &tracing_dyn_info_fops
);
3749 pr_warning("Could not create debugfs "
3750 "'dyn_ftrace_total_info' entry\n");
3752 #ifdef CONFIG_SYSPROF_TRACER
3753 init_tracer_sysprof_debugfs(d_tracer
);
3756 for_each_tracing_cpu(cpu
)
3757 tracing_init_debugfs_percpu(cpu
);
3762 int trace_vprintk(unsigned long ip
, int depth
, const char *fmt
, va_list args
)
3764 static raw_spinlock_t trace_buf_lock
= __RAW_SPIN_LOCK_UNLOCKED
;
3765 static char trace_buf
[TRACE_BUF_SIZE
];
3767 struct ring_buffer_event
*event
;
3768 struct trace_array
*tr
= &global_trace
;
3769 struct trace_array_cpu
*data
;
3770 int cpu
, len
= 0, size
, pc
;
3771 struct print_entry
*entry
;
3772 unsigned long irq_flags
;
3774 if (tracing_disabled
|| tracing_selftest_running
)
3777 pc
= preempt_count();
3778 preempt_disable_notrace();
3779 cpu
= raw_smp_processor_id();
3780 data
= tr
->data
[cpu
];
3782 if (unlikely(atomic_read(&data
->disabled
)))
3785 pause_graph_tracing();
3786 raw_local_irq_save(irq_flags
);
3787 __raw_spin_lock(&trace_buf_lock
);
3788 len
= vsnprintf(trace_buf
, TRACE_BUF_SIZE
, fmt
, args
);
3790 len
= min(len
, TRACE_BUF_SIZE
-1);
3793 size
= sizeof(*entry
) + len
+ 1;
3794 event
= trace_buffer_lock_reserve(tr
, TRACE_PRINT
, size
, irq_flags
, pc
);
3797 entry
= ring_buffer_event_data(event
);
3799 entry
->depth
= depth
;
3801 memcpy(&entry
->buf
, trace_buf
, len
);
3802 entry
->buf
[len
] = 0;
3803 ring_buffer_unlock_commit(tr
->buffer
, event
);
3806 __raw_spin_unlock(&trace_buf_lock
);
3807 raw_local_irq_restore(irq_flags
);
3808 unpause_graph_tracing();
3810 preempt_enable_notrace();
3814 EXPORT_SYMBOL_GPL(trace_vprintk
);
3816 int __ftrace_printk(unsigned long ip
, const char *fmt
, ...)
3821 if (!(trace_flags
& TRACE_ITER_PRINTK
))
3825 ret
= trace_vprintk(ip
, task_curr_ret_stack(current
), fmt
, ap
);
3829 EXPORT_SYMBOL_GPL(__ftrace_printk
);
3831 int __ftrace_vprintk(unsigned long ip
, const char *fmt
, va_list ap
)
3833 if (!(trace_flags
& TRACE_ITER_PRINTK
))
3836 return trace_vprintk(ip
, task_curr_ret_stack(current
), fmt
, ap
);
3838 EXPORT_SYMBOL_GPL(__ftrace_vprintk
);
3840 static int trace_panic_handler(struct notifier_block
*this,
3841 unsigned long event
, void *unused
)
3843 if (ftrace_dump_on_oops
)
3848 static struct notifier_block trace_panic_notifier
= {
3849 .notifier_call
= trace_panic_handler
,
3851 .priority
= 150 /* priority: INT_MAX >= x >= 0 */
3854 static int trace_die_handler(struct notifier_block
*self
,
3860 if (ftrace_dump_on_oops
)
3869 static struct notifier_block trace_die_notifier
= {
3870 .notifier_call
= trace_die_handler
,
3875 * printk is set to max of 1024, we really don't need it that big.
3876 * Nothing should be printing 1000 characters anyway.
3878 #define TRACE_MAX_PRINT 1000
3881 * Define here KERN_TRACE so that we have one place to modify
3882 * it if we decide to change what log level the ftrace dump
3885 #define KERN_TRACE KERN_EMERG
3888 trace_printk_seq(struct trace_seq
*s
)
3890 /* Probably should print a warning here. */
3894 /* should be zero ended, but we are paranoid. */
3895 s
->buffer
[s
->len
] = 0;
3897 printk(KERN_TRACE
"%s", s
->buffer
);
3902 void ftrace_dump(void)
3904 static DEFINE_SPINLOCK(ftrace_dump_lock
);
3905 /* use static because iter can be a bit big for the stack */
3906 static struct trace_iterator iter
;
3907 static int dump_ran
;
3908 unsigned long flags
;
3912 spin_lock_irqsave(&ftrace_dump_lock
, flags
);
3918 /* No turning back! */
3922 for_each_tracing_cpu(cpu
) {
3923 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
3926 /* don't look at user memory in panic mode */
3927 trace_flags
&= ~TRACE_ITER_SYM_USEROBJ
;
3929 printk(KERN_TRACE
"Dumping ftrace buffer:\n");
3931 /* Simulate the iterator */
3932 iter
.tr
= &global_trace
;
3933 iter
.trace
= current_trace
;
3934 iter
.cpu_file
= TRACE_PIPE_ALL_CPU
;
3937 * We need to stop all tracing on all CPUS to read the
3938 * the next buffer. This is a bit expensive, but is
3939 * not done often. We fill all what we can read,
3940 * and then release the locks again.
3943 while (!trace_empty(&iter
)) {
3946 printk(KERN_TRACE
"---------------------------------\n");
3950 /* reset all but tr, trace, and overruns */
3951 memset(&iter
.seq
, 0,
3952 sizeof(struct trace_iterator
) -
3953 offsetof(struct trace_iterator
, seq
));
3954 iter
.iter_flags
|= TRACE_FILE_LAT_FMT
;
3957 if (find_next_entry_inc(&iter
) != NULL
) {
3958 print_trace_line(&iter
);
3959 trace_consume(&iter
);
3962 trace_printk_seq(&iter
.seq
);
3966 printk(KERN_TRACE
" (ftrace buffer empty)\n");
3968 printk(KERN_TRACE
"---------------------------------\n");
3971 spin_unlock_irqrestore(&ftrace_dump_lock
, flags
);
3974 __init
static int tracer_alloc_buffers(void)
3976 struct trace_array_cpu
*data
;
3980 if (!alloc_cpumask_var(&tracing_buffer_mask
, GFP_KERNEL
))
3983 if (!alloc_cpumask_var(&tracing_cpumask
, GFP_KERNEL
))
3984 goto out_free_buffer_mask
;
3986 if (!alloc_cpumask_var(&tracing_reader_cpumask
, GFP_KERNEL
))
3987 goto out_free_tracing_cpumask
;
3989 cpumask_copy(tracing_buffer_mask
, cpu_possible_mask
);
3990 cpumask_copy(tracing_cpumask
, cpu_all_mask
);
3991 cpumask_clear(tracing_reader_cpumask
);
3993 /* TODO: make the number of buffers hot pluggable with CPUS */
3994 global_trace
.buffer
= ring_buffer_alloc(trace_buf_size
,
3995 TRACE_BUFFER_FLAGS
);
3996 if (!global_trace
.buffer
) {
3997 printk(KERN_ERR
"tracer: failed to allocate ring buffer!\n");
3999 goto out_free_cpumask
;
4001 global_trace
.entries
= ring_buffer_size(global_trace
.buffer
);
4004 #ifdef CONFIG_TRACER_MAX_TRACE
4005 max_tr
.buffer
= ring_buffer_alloc(trace_buf_size
,
4006 TRACE_BUFFER_FLAGS
);
4007 if (!max_tr
.buffer
) {
4008 printk(KERN_ERR
"tracer: failed to allocate max ring buffer!\n");
4010 ring_buffer_free(global_trace
.buffer
);
4011 goto out_free_cpumask
;
4013 max_tr
.entries
= ring_buffer_size(max_tr
.buffer
);
4014 WARN_ON(max_tr
.entries
!= global_trace
.entries
);
4017 /* Allocate the first page for all buffers */
4018 for_each_tracing_cpu(i
) {
4019 data
= global_trace
.data
[i
] = &per_cpu(global_trace_cpu
, i
);
4020 max_tr
.data
[i
] = &per_cpu(max_data
, i
);
4023 trace_init_cmdlines();
4025 register_tracer(&nop_trace
);
4026 current_trace
= &nop_trace
;
4027 #ifdef CONFIG_BOOT_TRACER
4028 register_tracer(&boot_tracer
);
4030 /* All seems OK, enable tracing */
4031 tracing_disabled
= 0;
4033 atomic_notifier_chain_register(&panic_notifier_list
,
4034 &trace_panic_notifier
);
4036 register_die_notifier(&trace_die_notifier
);
4040 free_cpumask_var(tracing_reader_cpumask
);
4041 out_free_tracing_cpumask
:
4042 free_cpumask_var(tracing_cpumask
);
4043 out_free_buffer_mask
:
4044 free_cpumask_var(tracing_buffer_mask
);
4049 __init
static int clear_boot_tracer(void)
4052 * The default tracer at boot buffer is an init section.
4053 * This function is called in lateinit. If we did not
4054 * find the boot tracer, then clear it out, to prevent
4055 * later registration from accessing the buffer that is
4056 * about to be freed.
4058 if (!default_bootup_tracer
)
4061 printk(KERN_INFO
"ftrace bootup tracer '%s' not registered.\n",
4062 default_bootup_tracer
);
4063 default_bootup_tracer
= NULL
;
4068 early_initcall(tracer_alloc_buffers
);
4069 fs_initcall(tracer_init_debugfs
);
4070 late_initcall(clear_boot_tracer
);