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/utsrelease.h>
15 #include <linux/kallsyms.h>
16 #include <linux/seq_file.h>
17 #include <linux/notifier.h>
18 #include <linux/debugfs.h>
19 #include <linux/pagemap.h>
20 #include <linux/hardirq.h>
21 #include <linux/linkage.h>
22 #include <linux/uaccess.h>
23 #include <linux/ftrace.h>
24 #include <linux/module.h>
25 #include <linux/percpu.h>
26 #include <linux/kdebug.h>
27 #include <linux/ctype.h>
28 #include <linux/init.h>
29 #include <linux/poll.h>
30 #include <linux/gfp.h>
32 #include <linux/kprobes.h>
33 #include <linux/seq_file.h>
34 #include <linux/writeback.h>
36 #include <linux/stacktrace.h>
37 #include <linux/ring_buffer.h>
38 #include <linux/irqflags.h>
41 #include "trace_output.h"
43 #define TRACE_BUFFER_FLAGS (RB_FL_OVERWRITE)
45 unsigned long __read_mostly tracing_max_latency
= (cycle_t
)ULONG_MAX
;
46 unsigned long __read_mostly tracing_thresh
;
49 * We need to change this state when a selftest is running.
50 * A selftest will lurk into the ring-buffer to count the
51 * entries inserted during the selftest although some concurrent
52 * insertions into the ring-buffer such as ftrace_printk could occurred
53 * at the same time, giving false positive or negative results.
55 static bool __read_mostly tracing_selftest_running
;
57 /* For tracers that don't implement custom flags */
58 static struct tracer_opt dummy_tracer_opt
[] = {
62 static struct tracer_flags dummy_tracer_flags
= {
64 .opts
= dummy_tracer_opt
67 static int dummy_set_flag(u32 old_flags
, u32 bit
, int set
)
73 * Kill all tracing for good (never come back).
74 * It is initialized to 1 but will turn to zero if the initialization
75 * of the tracer is successful. But that is the only place that sets
78 int tracing_disabled
= 1;
80 static DEFINE_PER_CPU(local_t
, ftrace_cpu_disabled
);
82 static inline void ftrace_disable_cpu(void)
85 local_inc(&__get_cpu_var(ftrace_cpu_disabled
));
88 static inline void ftrace_enable_cpu(void)
90 local_dec(&__get_cpu_var(ftrace_cpu_disabled
));
94 static cpumask_t __read_mostly tracing_buffer_mask
;
96 #define for_each_tracing_cpu(cpu) \
97 for_each_cpu_mask(cpu, tracing_buffer_mask)
100 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
102 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
103 * is set, then ftrace_dump is called. This will output the contents
104 * of the ftrace buffers to the console. This is very useful for
105 * capturing traces that lead to crashes and outputing it to a
108 * It is default off, but you can enable it with either specifying
109 * "ftrace_dump_on_oops" in the kernel command line, or setting
110 * /proc/sys/kernel/ftrace_dump_on_oops to true.
112 int ftrace_dump_on_oops
;
114 static int tracing_set_tracer(char *buf
);
116 static int __init
set_ftrace(char *str
)
118 tracing_set_tracer(str
);
121 __setup("ftrace", set_ftrace
);
123 static int __init
set_ftrace_dump_on_oops(char *str
)
125 ftrace_dump_on_oops
= 1;
128 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops
);
131 ns2usecs(cycle_t nsec
)
138 cycle_t
ftrace_now(int cpu
)
140 u64 ts
= ring_buffer_time_stamp(cpu
);
141 ring_buffer_normalize_time_stamp(cpu
, &ts
);
146 * The global_trace is the descriptor that holds the tracing
147 * buffers for the live tracing. For each CPU, it contains
148 * a link list of pages that will store trace entries. The
149 * page descriptor of the pages in the memory is used to hold
150 * the link list by linking the lru item in the page descriptor
151 * to each of the pages in the buffer per CPU.
153 * For each active CPU there is a data field that holds the
154 * pages for the buffer for that CPU. Each CPU has the same number
155 * of pages allocated for its buffer.
157 static struct trace_array global_trace
;
159 static DEFINE_PER_CPU(struct trace_array_cpu
, global_trace_cpu
);
162 * The max_tr is used to snapshot the global_trace when a maximum
163 * latency is reached. Some tracers will use this to store a maximum
164 * trace while it continues examining live traces.
166 * The buffers for the max_tr are set up the same as the global_trace.
167 * When a snapshot is taken, the link list of the max_tr is swapped
168 * with the link list of the global_trace and the buffers are reset for
169 * the global_trace so the tracing can continue.
171 static struct trace_array max_tr
;
173 static DEFINE_PER_CPU(struct trace_array_cpu
, max_data
);
175 /* tracer_enabled is used to toggle activation of a tracer */
176 static int tracer_enabled
= 1;
179 * tracing_is_enabled - return tracer_enabled status
181 * This function is used by other tracers to know the status
182 * of the tracer_enabled flag. Tracers may use this function
183 * to know if it should enable their features when starting
184 * up. See irqsoff tracer for an example (start_irqsoff_tracer).
186 int tracing_is_enabled(void)
188 return tracer_enabled
;
191 /* function tracing enabled */
192 int ftrace_function_enabled
;
195 * trace_buf_size is the size in bytes that is allocated
196 * for a buffer. Note, the number of bytes is always rounded
199 * This number is purposely set to a low number of 16384.
200 * If the dump on oops happens, it will be much appreciated
201 * to not have to wait for all that output. Anyway this can be
202 * boot time and run time configurable.
204 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
206 static unsigned long trace_buf_size
= TRACE_BUF_SIZE_DEFAULT
;
208 /* trace_types holds a link list of available tracers. */
209 static struct tracer
*trace_types __read_mostly
;
211 /* current_trace points to the tracer that is currently active */
212 static struct tracer
*current_trace __read_mostly
;
215 * max_tracer_type_len is used to simplify the allocating of
216 * buffers to read userspace tracer names. We keep track of
217 * the longest tracer name registered.
219 static int max_tracer_type_len
;
222 * trace_types_lock is used to protect the trace_types list.
223 * This lock is also used to keep user access serialized.
224 * Accesses from userspace will grab this lock while userspace
225 * activities happen inside the kernel.
227 static DEFINE_MUTEX(trace_types_lock
);
229 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
230 static DECLARE_WAIT_QUEUE_HEAD(trace_wait
);
232 /* trace_flags holds trace_options default values */
233 unsigned long trace_flags
= TRACE_ITER_PRINT_PARENT
| TRACE_ITER_PRINTK
|
237 * trace_wake_up - wake up tasks waiting for trace input
239 * Simply wakes up any task that is blocked on the trace_wait
240 * queue. These is used with trace_poll for tasks polling the trace.
242 void trace_wake_up(void)
245 * The runqueue_is_locked() can fail, but this is the best we
248 if (!(trace_flags
& TRACE_ITER_BLOCK
) && !runqueue_is_locked())
249 wake_up(&trace_wait
);
252 static int __init
set_buf_size(char *str
)
254 unsigned long buf_size
;
259 ret
= strict_strtoul(str
, 0, &buf_size
);
260 /* nr_entries can not be zero */
261 if (ret
< 0 || buf_size
== 0)
263 trace_buf_size
= buf_size
;
266 __setup("trace_buf_size=", set_buf_size
);
268 unsigned long nsecs_to_usecs(unsigned long nsecs
)
273 /* These must match the bit postions in trace_iterator_flags */
274 static const char *trace_options
[] = {
296 * ftrace_max_lock is used to protect the swapping of buffers
297 * when taking a max snapshot. The buffers themselves are
298 * protected by per_cpu spinlocks. But the action of the swap
299 * needs its own lock.
301 * This is defined as a raw_spinlock_t in order to help
302 * with performance when lockdep debugging is enabled.
304 static raw_spinlock_t ftrace_max_lock
=
305 (raw_spinlock_t
)__RAW_SPIN_LOCK_UNLOCKED
;
308 * Copy the new maximum trace into the separate maximum-trace
309 * structure. (this way the maximum trace is permanently saved,
310 * for later retrieval via /debugfs/tracing/latency_trace)
313 __update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
315 struct trace_array_cpu
*data
= tr
->data
[cpu
];
318 max_tr
.time_start
= data
->preempt_timestamp
;
320 data
= max_tr
.data
[cpu
];
321 data
->saved_latency
= tracing_max_latency
;
323 memcpy(data
->comm
, tsk
->comm
, TASK_COMM_LEN
);
324 data
->pid
= tsk
->pid
;
325 data
->uid
= task_uid(tsk
);
326 data
->nice
= tsk
->static_prio
- 20 - MAX_RT_PRIO
;
327 data
->policy
= tsk
->policy
;
328 data
->rt_priority
= tsk
->rt_priority
;
330 /* record this tasks comm */
331 tracing_record_cmdline(current
);
335 trace_seq_reset(struct trace_seq
*s
)
341 ssize_t
trace_seq_to_user(struct trace_seq
*s
, char __user
*ubuf
, size_t cnt
)
346 if (s
->len
<= s
->readpos
)
349 len
= s
->len
- s
->readpos
;
352 ret
= copy_to_user(ubuf
, s
->buffer
+ s
->readpos
, cnt
);
361 trace_print_seq(struct seq_file
*m
, struct trace_seq
*s
)
363 int len
= s
->len
>= PAGE_SIZE
? PAGE_SIZE
- 1 : s
->len
;
366 seq_puts(m
, s
->buffer
);
372 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
374 * @tsk: the task with the latency
375 * @cpu: The cpu that initiated the trace.
377 * Flip the buffers between the @tr and the max_tr and record information
378 * about which task was the cause of this latency.
381 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
383 struct ring_buffer
*buf
= tr
->buffer
;
385 WARN_ON_ONCE(!irqs_disabled());
386 __raw_spin_lock(&ftrace_max_lock
);
388 tr
->buffer
= max_tr
.buffer
;
391 ftrace_disable_cpu();
392 ring_buffer_reset(tr
->buffer
);
395 __update_max_tr(tr
, tsk
, cpu
);
396 __raw_spin_unlock(&ftrace_max_lock
);
400 * update_max_tr_single - only copy one trace over, and reset the rest
402 * @tsk - task with the latency
403 * @cpu - the cpu of the buffer to copy.
405 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
408 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
412 WARN_ON_ONCE(!irqs_disabled());
413 __raw_spin_lock(&ftrace_max_lock
);
415 ftrace_disable_cpu();
417 ring_buffer_reset(max_tr
.buffer
);
418 ret
= ring_buffer_swap_cpu(max_tr
.buffer
, tr
->buffer
, cpu
);
424 __update_max_tr(tr
, tsk
, cpu
);
425 __raw_spin_unlock(&ftrace_max_lock
);
429 * register_tracer - register a tracer with the ftrace system.
430 * @type - the plugin for the tracer
432 * Register a new plugin tracer.
434 int register_tracer(struct tracer
*type
)
441 pr_info("Tracer must have a name\n");
446 * When this gets called we hold the BKL which means that
447 * preemption is disabled. Various trace selftests however
448 * need to disable and enable preemption for successful tests.
449 * So we drop the BKL here and grab it after the tests again.
452 mutex_lock(&trace_types_lock
);
454 tracing_selftest_running
= true;
456 for (t
= trace_types
; t
; t
= t
->next
) {
457 if (strcmp(type
->name
, t
->name
) == 0) {
459 pr_info("Trace %s already registered\n",
467 type
->set_flag
= &dummy_set_flag
;
469 type
->flags
= &dummy_tracer_flags
;
471 if (!type
->flags
->opts
)
472 type
->flags
->opts
= dummy_tracer_opt
;
474 #ifdef CONFIG_FTRACE_STARTUP_TEST
475 if (type
->selftest
) {
476 struct tracer
*saved_tracer
= current_trace
;
477 struct trace_array
*tr
= &global_trace
;
481 * Run a selftest on this tracer.
482 * Here we reset the trace buffer, and set the current
483 * tracer to be this tracer. The tracer can then run some
484 * internal tracing to verify that everything is in order.
485 * If we fail, we do not register this tracer.
487 for_each_tracing_cpu(i
)
488 tracing_reset(tr
, i
);
490 current_trace
= type
;
491 /* the test is responsible for initializing and enabling */
492 pr_info("Testing tracer %s: ", type
->name
);
493 ret
= type
->selftest(type
, tr
);
494 /* the test is responsible for resetting too */
495 current_trace
= saved_tracer
;
497 printk(KERN_CONT
"FAILED!\n");
500 /* Only reset on passing, to avoid touching corrupted buffers */
501 for_each_tracing_cpu(i
)
502 tracing_reset(tr
, i
);
504 printk(KERN_CONT
"PASSED\n");
508 type
->next
= trace_types
;
510 len
= strlen(type
->name
);
511 if (len
> max_tracer_type_len
)
512 max_tracer_type_len
= len
;
515 tracing_selftest_running
= false;
516 mutex_unlock(&trace_types_lock
);
522 void unregister_tracer(struct tracer
*type
)
527 mutex_lock(&trace_types_lock
);
528 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
532 pr_info("Trace %s not registered\n", type
->name
);
537 if (strlen(type
->name
) != max_tracer_type_len
)
540 max_tracer_type_len
= 0;
541 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
542 len
= strlen((*t
)->name
);
543 if (len
> max_tracer_type_len
)
544 max_tracer_type_len
= len
;
547 mutex_unlock(&trace_types_lock
);
550 void tracing_reset(struct trace_array
*tr
, int cpu
)
552 ftrace_disable_cpu();
553 ring_buffer_reset_cpu(tr
->buffer
, cpu
);
557 void tracing_reset_online_cpus(struct trace_array
*tr
)
561 tr
->time_start
= ftrace_now(tr
->cpu
);
563 for_each_online_cpu(cpu
)
564 tracing_reset(tr
, cpu
);
567 #define SAVED_CMDLINES 128
568 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
569 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
570 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
571 static int cmdline_idx
;
572 static DEFINE_SPINLOCK(trace_cmdline_lock
);
574 /* temporary disable recording */
575 atomic_t trace_record_cmdline_disabled __read_mostly
;
577 static void trace_init_cmdlines(void)
579 memset(&map_pid_to_cmdline
, -1, sizeof(map_pid_to_cmdline
));
580 memset(&map_cmdline_to_pid
, -1, sizeof(map_cmdline_to_pid
));
584 static int trace_stop_count
;
585 static DEFINE_SPINLOCK(tracing_start_lock
);
588 * ftrace_off_permanent - disable all ftrace code permanently
590 * This should only be called when a serious anomally has
591 * been detected. This will turn off the function tracing,
592 * ring buffers, and other tracing utilites. It takes no
593 * locks and can be called from any context.
595 void ftrace_off_permanent(void)
597 tracing_disabled
= 1;
599 tracing_off_permanent();
603 * tracing_start - quick start of the tracer
605 * If tracing is enabled but was stopped by tracing_stop,
606 * this will start the tracer back up.
608 void tracing_start(void)
610 struct ring_buffer
*buffer
;
613 if (tracing_disabled
)
616 spin_lock_irqsave(&tracing_start_lock
, flags
);
617 if (--trace_stop_count
)
620 if (trace_stop_count
< 0) {
621 /* Someone screwed up their debugging */
623 trace_stop_count
= 0;
628 buffer
= global_trace
.buffer
;
630 ring_buffer_record_enable(buffer
);
632 buffer
= max_tr
.buffer
;
634 ring_buffer_record_enable(buffer
);
638 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
642 * tracing_stop - quick stop of the tracer
644 * Light weight way to stop tracing. Use in conjunction with
647 void tracing_stop(void)
649 struct ring_buffer
*buffer
;
653 spin_lock_irqsave(&tracing_start_lock
, flags
);
654 if (trace_stop_count
++)
657 buffer
= global_trace
.buffer
;
659 ring_buffer_record_disable(buffer
);
661 buffer
= max_tr
.buffer
;
663 ring_buffer_record_disable(buffer
);
666 spin_unlock_irqrestore(&tracing_start_lock
, flags
);
669 void trace_stop_cmdline_recording(void);
671 static void trace_save_cmdline(struct task_struct
*tsk
)
676 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
680 * It's not the end of the world if we don't get
681 * the lock, but we also don't want to spin
682 * nor do we want to disable interrupts,
683 * so if we miss here, then better luck next time.
685 if (!spin_trylock(&trace_cmdline_lock
))
688 idx
= map_pid_to_cmdline
[tsk
->pid
];
689 if (idx
>= SAVED_CMDLINES
) {
690 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
692 map
= map_cmdline_to_pid
[idx
];
693 if (map
<= PID_MAX_DEFAULT
)
694 map_pid_to_cmdline
[map
] = (unsigned)-1;
696 map_pid_to_cmdline
[tsk
->pid
] = idx
;
701 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
703 spin_unlock(&trace_cmdline_lock
);
706 char *trace_find_cmdline(int pid
)
708 char *cmdline
= "<...>";
714 if (pid
> PID_MAX_DEFAULT
)
717 map
= map_pid_to_cmdline
[pid
];
718 if (map
>= SAVED_CMDLINES
)
721 cmdline
= saved_cmdlines
[map
];
727 void tracing_record_cmdline(struct task_struct
*tsk
)
729 if (atomic_read(&trace_record_cmdline_disabled
))
732 trace_save_cmdline(tsk
);
736 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
,
739 struct task_struct
*tsk
= current
;
741 entry
->preempt_count
= pc
& 0xff;
742 entry
->pid
= (tsk
) ? tsk
->pid
: 0;
743 entry
->tgid
= (tsk
) ? tsk
->tgid
: 0;
745 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
746 (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
748 TRACE_FLAG_IRQS_NOSUPPORT
|
750 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
751 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
752 (need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0);
756 trace_function(struct trace_array
*tr
, struct trace_array_cpu
*data
,
757 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
760 struct ring_buffer_event
*event
;
761 struct ftrace_entry
*entry
;
762 unsigned long irq_flags
;
764 /* If we are reading the ring buffer, don't trace */
765 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
768 event
= ring_buffer_lock_reserve(tr
->buffer
, sizeof(*entry
),
772 entry
= ring_buffer_event_data(event
);
773 tracing_generic_entry_update(&entry
->ent
, flags
, pc
);
774 entry
->ent
.type
= TRACE_FN
;
776 entry
->parent_ip
= parent_ip
;
777 ring_buffer_unlock_commit(tr
->buffer
, event
, irq_flags
);
780 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
781 static void __trace_graph_entry(struct trace_array
*tr
,
782 struct trace_array_cpu
*data
,
783 struct ftrace_graph_ent
*trace
,
787 struct ring_buffer_event
*event
;
788 struct ftrace_graph_ent_entry
*entry
;
789 unsigned long irq_flags
;
791 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
794 event
= ring_buffer_lock_reserve(global_trace
.buffer
, sizeof(*entry
),
798 entry
= ring_buffer_event_data(event
);
799 tracing_generic_entry_update(&entry
->ent
, flags
, pc
);
800 entry
->ent
.type
= TRACE_GRAPH_ENT
;
801 entry
->graph_ent
= *trace
;
802 ring_buffer_unlock_commit(global_trace
.buffer
, event
, irq_flags
);
805 static void __trace_graph_return(struct trace_array
*tr
,
806 struct trace_array_cpu
*data
,
807 struct ftrace_graph_ret
*trace
,
811 struct ring_buffer_event
*event
;
812 struct ftrace_graph_ret_entry
*entry
;
813 unsigned long irq_flags
;
815 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled
))))
818 event
= ring_buffer_lock_reserve(global_trace
.buffer
, sizeof(*entry
),
822 entry
= ring_buffer_event_data(event
);
823 tracing_generic_entry_update(&entry
->ent
, flags
, pc
);
824 entry
->ent
.type
= TRACE_GRAPH_RET
;
826 ring_buffer_unlock_commit(global_trace
.buffer
, event
, irq_flags
);
831 ftrace(struct trace_array
*tr
, struct trace_array_cpu
*data
,
832 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
,
835 if (likely(!atomic_read(&data
->disabled
)))
836 trace_function(tr
, data
, ip
, parent_ip
, flags
, pc
);
839 static void ftrace_trace_stack(struct trace_array
*tr
,
840 struct trace_array_cpu
*data
,
844 #ifdef CONFIG_STACKTRACE
845 struct ring_buffer_event
*event
;
846 struct stack_entry
*entry
;
847 struct stack_trace trace
;
848 unsigned long irq_flags
;
850 if (!(trace_flags
& TRACE_ITER_STACKTRACE
))
853 event
= ring_buffer_lock_reserve(tr
->buffer
, sizeof(*entry
),
857 entry
= ring_buffer_event_data(event
);
858 tracing_generic_entry_update(&entry
->ent
, flags
, pc
);
859 entry
->ent
.type
= TRACE_STACK
;
861 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
863 trace
.nr_entries
= 0;
864 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
866 trace
.entries
= entry
->caller
;
868 save_stack_trace(&trace
);
869 ring_buffer_unlock_commit(tr
->buffer
, event
, irq_flags
);
873 void __trace_stack(struct trace_array
*tr
,
874 struct trace_array_cpu
*data
,
878 ftrace_trace_stack(tr
, data
, flags
, skip
, preempt_count());
881 static void ftrace_trace_userstack(struct trace_array
*tr
,
882 struct trace_array_cpu
*data
,
883 unsigned long flags
, int pc
)
885 #ifdef CONFIG_STACKTRACE
886 struct ring_buffer_event
*event
;
887 struct userstack_entry
*entry
;
888 struct stack_trace trace
;
889 unsigned long irq_flags
;
891 if (!(trace_flags
& TRACE_ITER_USERSTACKTRACE
))
894 event
= ring_buffer_lock_reserve(tr
->buffer
, sizeof(*entry
),
898 entry
= ring_buffer_event_data(event
);
899 tracing_generic_entry_update(&entry
->ent
, flags
, pc
);
900 entry
->ent
.type
= TRACE_USER_STACK
;
902 memset(&entry
->caller
, 0, sizeof(entry
->caller
));
904 trace
.nr_entries
= 0;
905 trace
.max_entries
= FTRACE_STACK_ENTRIES
;
907 trace
.entries
= entry
->caller
;
909 save_stack_trace_user(&trace
);
910 ring_buffer_unlock_commit(tr
->buffer
, event
, irq_flags
);
914 void __trace_userstack(struct trace_array
*tr
,
915 struct trace_array_cpu
*data
,
918 ftrace_trace_userstack(tr
, data
, flags
, preempt_count());
922 ftrace_trace_special(void *__tr
, void *__data
,
923 unsigned long arg1
, unsigned long arg2
, unsigned long arg3
,
926 struct ring_buffer_event
*event
;
927 struct trace_array_cpu
*data
= __data
;
928 struct trace_array
*tr
= __tr
;
929 struct special_entry
*entry
;
930 unsigned long irq_flags
;
932 event
= ring_buffer_lock_reserve(tr
->buffer
, sizeof(*entry
),
936 entry
= ring_buffer_event_data(event
);
937 tracing_generic_entry_update(&entry
->ent
, 0, pc
);
938 entry
->ent
.type
= TRACE_SPECIAL
;
942 ring_buffer_unlock_commit(tr
->buffer
, event
, irq_flags
);
943 ftrace_trace_stack(tr
, data
, irq_flags
, 4, pc
);
944 ftrace_trace_userstack(tr
, data
, irq_flags
, pc
);
950 __trace_special(void *__tr
, void *__data
,
951 unsigned long arg1
, unsigned long arg2
, unsigned long arg3
)
953 ftrace_trace_special(__tr
, __data
, arg1
, arg2
, arg3
, preempt_count());
957 tracing_sched_switch_trace(struct trace_array
*tr
,
958 struct trace_array_cpu
*data
,
959 struct task_struct
*prev
,
960 struct task_struct
*next
,
961 unsigned long flags
, int pc
)
963 struct ring_buffer_event
*event
;
964 struct ctx_switch_entry
*entry
;
965 unsigned long irq_flags
;
967 event
= ring_buffer_lock_reserve(tr
->buffer
, sizeof(*entry
),
971 entry
= ring_buffer_event_data(event
);
972 tracing_generic_entry_update(&entry
->ent
, flags
, pc
);
973 entry
->ent
.type
= TRACE_CTX
;
974 entry
->prev_pid
= prev
->pid
;
975 entry
->prev_prio
= prev
->prio
;
976 entry
->prev_state
= prev
->state
;
977 entry
->next_pid
= next
->pid
;
978 entry
->next_prio
= next
->prio
;
979 entry
->next_state
= next
->state
;
980 entry
->next_cpu
= task_cpu(next
);
981 ring_buffer_unlock_commit(tr
->buffer
, event
, irq_flags
);
982 ftrace_trace_stack(tr
, data
, flags
, 5, pc
);
983 ftrace_trace_userstack(tr
, data
, flags
, pc
);
987 tracing_sched_wakeup_trace(struct trace_array
*tr
,
988 struct trace_array_cpu
*data
,
989 struct task_struct
*wakee
,
990 struct task_struct
*curr
,
991 unsigned long flags
, int pc
)
993 struct ring_buffer_event
*event
;
994 struct ctx_switch_entry
*entry
;
995 unsigned long irq_flags
;
997 event
= ring_buffer_lock_reserve(tr
->buffer
, sizeof(*entry
),
1001 entry
= ring_buffer_event_data(event
);
1002 tracing_generic_entry_update(&entry
->ent
, flags
, pc
);
1003 entry
->ent
.type
= TRACE_WAKE
;
1004 entry
->prev_pid
= curr
->pid
;
1005 entry
->prev_prio
= curr
->prio
;
1006 entry
->prev_state
= curr
->state
;
1007 entry
->next_pid
= wakee
->pid
;
1008 entry
->next_prio
= wakee
->prio
;
1009 entry
->next_state
= wakee
->state
;
1010 entry
->next_cpu
= task_cpu(wakee
);
1011 ring_buffer_unlock_commit(tr
->buffer
, event
, irq_flags
);
1012 ftrace_trace_stack(tr
, data
, flags
, 6, pc
);
1013 ftrace_trace_userstack(tr
, data
, flags
, pc
);
1019 ftrace_special(unsigned long arg1
, unsigned long arg2
, unsigned long arg3
)
1021 struct trace_array
*tr
= &global_trace
;
1022 struct trace_array_cpu
*data
;
1023 unsigned long flags
;
1027 if (tracing_disabled
)
1030 pc
= preempt_count();
1031 local_irq_save(flags
);
1032 cpu
= raw_smp_processor_id();
1033 data
= tr
->data
[cpu
];
1035 if (likely(atomic_inc_return(&data
->disabled
) == 1))
1036 ftrace_trace_special(tr
, data
, arg1
, arg2
, arg3
, pc
);
1038 atomic_dec(&data
->disabled
);
1039 local_irq_restore(flags
);
1042 #ifdef CONFIG_FUNCTION_TRACER
1044 function_trace_call_preempt_only(unsigned long ip
, unsigned long parent_ip
)
1046 struct trace_array
*tr
= &global_trace
;
1047 struct trace_array_cpu
*data
;
1048 unsigned long flags
;
1053 if (unlikely(!ftrace_function_enabled
))
1056 pc
= preempt_count();
1057 resched
= ftrace_preempt_disable();
1058 local_save_flags(flags
);
1059 cpu
= raw_smp_processor_id();
1060 data
= tr
->data
[cpu
];
1061 disabled
= atomic_inc_return(&data
->disabled
);
1063 if (likely(disabled
== 1))
1064 trace_function(tr
, data
, ip
, parent_ip
, flags
, pc
);
1066 atomic_dec(&data
->disabled
);
1067 ftrace_preempt_enable(resched
);
1071 function_trace_call(unsigned long ip
, unsigned long parent_ip
)
1073 struct trace_array
*tr
= &global_trace
;
1074 struct trace_array_cpu
*data
;
1075 unsigned long flags
;
1080 if (unlikely(!ftrace_function_enabled
))
1084 * Need to use raw, since this must be called before the
1085 * recursive protection is performed.
1087 local_irq_save(flags
);
1088 cpu
= raw_smp_processor_id();
1089 data
= tr
->data
[cpu
];
1090 disabled
= atomic_inc_return(&data
->disabled
);
1092 if (likely(disabled
== 1)) {
1093 pc
= preempt_count();
1094 trace_function(tr
, data
, ip
, parent_ip
, flags
, pc
);
1097 atomic_dec(&data
->disabled
);
1098 local_irq_restore(flags
);
1101 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1102 int trace_graph_entry(struct ftrace_graph_ent
*trace
)
1104 struct trace_array
*tr
= &global_trace
;
1105 struct trace_array_cpu
*data
;
1106 unsigned long flags
;
1111 if (!ftrace_trace_task(current
))
1114 if (!ftrace_graph_addr(trace
->func
))
1117 local_irq_save(flags
);
1118 cpu
= raw_smp_processor_id();
1119 data
= tr
->data
[cpu
];
1120 disabled
= atomic_inc_return(&data
->disabled
);
1121 if (likely(disabled
== 1)) {
1122 pc
= preempt_count();
1123 __trace_graph_entry(tr
, data
, trace
, flags
, pc
);
1125 /* Only do the atomic if it is not already set */
1126 if (!test_tsk_trace_graph(current
))
1127 set_tsk_trace_graph(current
);
1128 atomic_dec(&data
->disabled
);
1129 local_irq_restore(flags
);
1134 void trace_graph_return(struct ftrace_graph_ret
*trace
)
1136 struct trace_array
*tr
= &global_trace
;
1137 struct trace_array_cpu
*data
;
1138 unsigned long flags
;
1143 local_irq_save(flags
);
1144 cpu
= raw_smp_processor_id();
1145 data
= tr
->data
[cpu
];
1146 disabled
= atomic_inc_return(&data
->disabled
);
1147 if (likely(disabled
== 1)) {
1148 pc
= preempt_count();
1149 __trace_graph_return(tr
, data
, trace
, flags
, pc
);
1152 clear_tsk_trace_graph(current
);
1153 atomic_dec(&data
->disabled
);
1154 local_irq_restore(flags
);
1156 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1158 static struct ftrace_ops trace_ops __read_mostly
=
1160 .func
= function_trace_call
,
1163 void tracing_start_function_trace(void)
1165 ftrace_function_enabled
= 0;
1167 if (trace_flags
& TRACE_ITER_PREEMPTONLY
)
1168 trace_ops
.func
= function_trace_call_preempt_only
;
1170 trace_ops
.func
= function_trace_call
;
1172 register_ftrace_function(&trace_ops
);
1173 ftrace_function_enabled
= 1;
1176 void tracing_stop_function_trace(void)
1178 ftrace_function_enabled
= 0;
1179 unregister_ftrace_function(&trace_ops
);
1183 enum trace_file_type
{
1184 TRACE_FILE_LAT_FMT
= 1,
1185 TRACE_FILE_ANNOTATE
= 2,
1188 static void trace_iterator_increment(struct trace_iterator
*iter
, int cpu
)
1190 /* Don't allow ftrace to trace into the ring buffers */
1191 ftrace_disable_cpu();
1194 if (iter
->buffer_iter
[iter
->cpu
])
1195 ring_buffer_read(iter
->buffer_iter
[iter
->cpu
], NULL
);
1197 ftrace_enable_cpu();
1200 static struct trace_entry
*
1201 peek_next_entry(struct trace_iterator
*iter
, int cpu
, u64
*ts
)
1203 struct ring_buffer_event
*event
;
1204 struct ring_buffer_iter
*buf_iter
= iter
->buffer_iter
[cpu
];
1206 /* Don't allow ftrace to trace into the ring buffers */
1207 ftrace_disable_cpu();
1210 event
= ring_buffer_iter_peek(buf_iter
, ts
);
1212 event
= ring_buffer_peek(iter
->tr
->buffer
, cpu
, ts
);
1214 ftrace_enable_cpu();
1216 return event
? ring_buffer_event_data(event
) : NULL
;
1219 static struct trace_entry
*
1220 __find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
, u64
*ent_ts
)
1222 struct ring_buffer
*buffer
= iter
->tr
->buffer
;
1223 struct trace_entry
*ent
, *next
= NULL
;
1224 u64 next_ts
= 0, ts
;
1228 for_each_tracing_cpu(cpu
) {
1230 if (ring_buffer_empty_cpu(buffer
, cpu
))
1233 ent
= peek_next_entry(iter
, cpu
, &ts
);
1236 * Pick the entry with the smallest timestamp:
1238 if (ent
&& (!next
|| ts
< next_ts
)) {
1246 *ent_cpu
= next_cpu
;
1254 /* Find the next real entry, without updating the iterator itself */
1255 static struct trace_entry
*
1256 find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
, u64
*ent_ts
)
1258 return __find_next_entry(iter
, ent_cpu
, ent_ts
);
1261 /* Find the next real entry, and increment the iterator to the next entry */
1262 static void *find_next_entry_inc(struct trace_iterator
*iter
)
1264 iter
->ent
= __find_next_entry(iter
, &iter
->cpu
, &iter
->ts
);
1267 trace_iterator_increment(iter
, iter
->cpu
);
1269 return iter
->ent
? iter
: NULL
;
1272 static void trace_consume(struct trace_iterator
*iter
)
1274 /* Don't allow ftrace to trace into the ring buffers */
1275 ftrace_disable_cpu();
1276 ring_buffer_consume(iter
->tr
->buffer
, iter
->cpu
, &iter
->ts
);
1277 ftrace_enable_cpu();
1280 static void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1282 struct trace_iterator
*iter
= m
->private;
1288 /* can't go backwards */
1293 ent
= find_next_entry_inc(iter
);
1297 while (ent
&& iter
->idx
< i
)
1298 ent
= find_next_entry_inc(iter
);
1305 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
1307 struct trace_iterator
*iter
= m
->private;
1312 mutex_lock(&trace_types_lock
);
1314 if (!current_trace
|| current_trace
!= iter
->trace
) {
1315 mutex_unlock(&trace_types_lock
);
1319 atomic_inc(&trace_record_cmdline_disabled
);
1321 if (*pos
!= iter
->pos
) {
1326 ftrace_disable_cpu();
1328 for_each_tracing_cpu(cpu
) {
1329 ring_buffer_iter_reset(iter
->buffer_iter
[cpu
]);
1332 ftrace_enable_cpu();
1334 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
1339 p
= s_next(m
, p
, &l
);
1345 static void s_stop(struct seq_file
*m
, void *p
)
1347 atomic_dec(&trace_record_cmdline_disabled
);
1348 mutex_unlock(&trace_types_lock
);
1351 static void print_lat_help_header(struct seq_file
*m
)
1353 seq_puts(m
, "# _------=> CPU# \n");
1354 seq_puts(m
, "# / _-----=> irqs-off \n");
1355 seq_puts(m
, "# | / _----=> need-resched \n");
1356 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
1357 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
1358 seq_puts(m
, "# |||| / \n");
1359 seq_puts(m
, "# ||||| delay \n");
1360 seq_puts(m
, "# cmd pid ||||| time | caller \n");
1361 seq_puts(m
, "# \\ / ||||| \\ | / \n");
1364 static void print_func_help_header(struct seq_file
*m
)
1366 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1367 seq_puts(m
, "# | | | | |\n");
1372 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
1374 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1375 struct trace_array
*tr
= iter
->tr
;
1376 struct trace_array_cpu
*data
= tr
->data
[tr
->cpu
];
1377 struct tracer
*type
= current_trace
;
1378 unsigned long total
;
1379 unsigned long entries
;
1380 const char *name
= "preemption";
1385 entries
= ring_buffer_entries(iter
->tr
->buffer
);
1387 ring_buffer_overruns(iter
->tr
->buffer
);
1389 seq_printf(m
, "%s latency trace v1.1.5 on %s\n",
1391 seq_puts(m
, "-----------------------------------"
1392 "---------------------------------\n");
1393 seq_printf(m
, " latency: %lu us, #%lu/%lu, CPU#%d |"
1394 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1395 nsecs_to_usecs(data
->saved_latency
),
1399 #if defined(CONFIG_PREEMPT_NONE)
1401 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1403 #elif defined(CONFIG_PREEMPT)
1408 /* These are reserved for later use */
1411 seq_printf(m
, " #P:%d)\n", num_online_cpus());
1415 seq_puts(m
, " -----------------\n");
1416 seq_printf(m
, " | task: %.16s-%d "
1417 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1418 data
->comm
, data
->pid
, data
->uid
, data
->nice
,
1419 data
->policy
, data
->rt_priority
);
1420 seq_puts(m
, " -----------------\n");
1422 if (data
->critical_start
) {
1423 seq_puts(m
, " => started at: ");
1424 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
1425 trace_print_seq(m
, &iter
->seq
);
1426 seq_puts(m
, "\n => ended at: ");
1427 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
1428 trace_print_seq(m
, &iter
->seq
);
1436 lat_print_generic(struct trace_seq
*s
, struct trace_entry
*entry
, int cpu
)
1438 int hardirq
, softirq
;
1441 comm
= trace_find_cmdline(entry
->pid
);
1443 trace_seq_printf(s
, "%8.8s-%-5d ", comm
, entry
->pid
);
1444 trace_seq_printf(s
, "%3d", cpu
);
1445 trace_seq_printf(s
, "%c%c",
1446 (entry
->flags
& TRACE_FLAG_IRQS_OFF
) ? 'd' :
1447 (entry
->flags
& TRACE_FLAG_IRQS_NOSUPPORT
) ? 'X' : '.',
1448 ((entry
->flags
& TRACE_FLAG_NEED_RESCHED
) ? 'N' : '.'));
1450 hardirq
= entry
->flags
& TRACE_FLAG_HARDIRQ
;
1451 softirq
= entry
->flags
& TRACE_FLAG_SOFTIRQ
;
1452 if (hardirq
&& softirq
) {
1453 trace_seq_putc(s
, 'H');
1456 trace_seq_putc(s
, 'h');
1459 trace_seq_putc(s
, 's');
1461 trace_seq_putc(s
, '.');
1465 if (entry
->preempt_count
)
1466 trace_seq_printf(s
, "%x", entry
->preempt_count
);
1468 trace_seq_puts(s
, ".");
1471 unsigned long preempt_mark_thresh
= 100;
1474 lat_print_timestamp(struct trace_seq
*s
, u64 abs_usecs
,
1475 unsigned long rel_usecs
)
1477 trace_seq_printf(s
, " %4lldus", abs_usecs
);
1478 if (rel_usecs
> preempt_mark_thresh
)
1479 trace_seq_puts(s
, "!: ");
1480 else if (rel_usecs
> 1)
1481 trace_seq_puts(s
, "+: ");
1483 trace_seq_puts(s
, " : ");
1486 static void test_cpu_buff_start(struct trace_iterator
*iter
)
1488 struct trace_seq
*s
= &iter
->seq
;
1490 if (!(trace_flags
& TRACE_ITER_ANNOTATE
))
1493 if (!(iter
->iter_flags
& TRACE_FILE_ANNOTATE
))
1496 if (cpu_isset(iter
->cpu
, iter
->started
))
1499 cpu_set(iter
->cpu
, iter
->started
);
1500 trace_seq_printf(s
, "##### CPU %u buffer started ####\n", iter
->cpu
);
1503 static enum print_line_t
1504 print_lat_fmt(struct trace_iterator
*iter
, unsigned int trace_idx
, int cpu
)
1506 struct trace_seq
*s
= &iter
->seq
;
1507 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1508 struct trace_entry
*next_entry
;
1509 struct trace_event
*event
;
1510 unsigned long verbose
= (trace_flags
& TRACE_ITER_VERBOSE
);
1511 struct trace_entry
*entry
= iter
->ent
;
1512 unsigned long abs_usecs
;
1513 unsigned long rel_usecs
;
1518 test_cpu_buff_start(iter
);
1520 next_entry
= find_next_entry(iter
, NULL
, &next_ts
);
1523 rel_usecs
= ns2usecs(next_ts
- iter
->ts
);
1524 abs_usecs
= ns2usecs(iter
->ts
- iter
->tr
->time_start
);
1527 comm
= trace_find_cmdline(entry
->pid
);
1528 trace_seq_printf(s
, "%16s %5d %3d %d %08x %08x [%08lx]"
1529 " %ld.%03ldms (+%ld.%03ldms): ",
1531 entry
->pid
, cpu
, entry
->flags
,
1532 entry
->preempt_count
, trace_idx
,
1535 abs_usecs
% 1000, rel_usecs
/1000,
1538 lat_print_generic(s
, entry
, cpu
);
1539 lat_print_timestamp(s
, abs_usecs
, rel_usecs
);
1542 event
= ftrace_find_event(entry
->type
);
1543 if (event
&& event
->latency_trace
) {
1544 ret
= event
->latency_trace(s
, entry
, sym_flags
);
1547 return TRACE_TYPE_HANDLED
;
1550 trace_seq_printf(s
, "Unknown type %d\n", entry
->type
);
1551 return TRACE_TYPE_HANDLED
;
1554 static enum print_line_t
print_trace_fmt(struct trace_iterator
*iter
)
1556 struct trace_seq
*s
= &iter
->seq
;
1557 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1558 struct trace_entry
*entry
;
1559 struct trace_event
*event
;
1560 unsigned long usec_rem
;
1561 unsigned long long t
;
1568 test_cpu_buff_start(iter
);
1570 comm
= trace_find_cmdline(iter
->ent
->pid
);
1572 t
= ns2usecs(iter
->ts
);
1573 usec_rem
= do_div(t
, 1000000ULL);
1574 secs
= (unsigned long)t
;
1576 ret
= trace_seq_printf(s
, "%16s-%-5d ", comm
, entry
->pid
);
1578 return TRACE_TYPE_PARTIAL_LINE
;
1579 ret
= trace_seq_printf(s
, "[%03d] ", iter
->cpu
);
1581 return TRACE_TYPE_PARTIAL_LINE
;
1582 ret
= trace_seq_printf(s
, "%5lu.%06lu: ", secs
, usec_rem
);
1584 return TRACE_TYPE_PARTIAL_LINE
;
1586 event
= ftrace_find_event(entry
->type
);
1587 if (event
&& event
->trace
) {
1588 ret
= event
->trace(s
, entry
, sym_flags
);
1591 return TRACE_TYPE_HANDLED
;
1593 ret
= trace_seq_printf(s
, "Unknown type %d\n", entry
->type
);
1595 return TRACE_TYPE_PARTIAL_LINE
;
1597 return TRACE_TYPE_HANDLED
;
1600 static enum print_line_t
print_raw_fmt(struct trace_iterator
*iter
)
1602 struct trace_seq
*s
= &iter
->seq
;
1603 struct trace_entry
*entry
;
1604 struct trace_event
*event
;
1609 ret
= trace_seq_printf(s
, "%d %d %llu ",
1610 entry
->pid
, iter
->cpu
, iter
->ts
);
1612 return TRACE_TYPE_PARTIAL_LINE
;
1614 event
= ftrace_find_event(entry
->type
);
1615 if (event
&& event
->raw
) {
1616 ret
= event
->raw(s
, entry
, 0);
1619 return TRACE_TYPE_HANDLED
;
1621 ret
= trace_seq_printf(s
, "%d ?\n", entry
->type
);
1623 return TRACE_TYPE_PARTIAL_LINE
;
1625 return TRACE_TYPE_HANDLED
;
1628 static enum print_line_t
print_hex_fmt(struct trace_iterator
*iter
)
1630 struct trace_seq
*s
= &iter
->seq
;
1631 unsigned char newline
= '\n';
1632 struct trace_entry
*entry
;
1633 struct trace_event
*event
;
1637 SEQ_PUT_HEX_FIELD_RET(s
, entry
->pid
);
1638 SEQ_PUT_HEX_FIELD_RET(s
, iter
->cpu
);
1639 SEQ_PUT_HEX_FIELD_RET(s
, iter
->ts
);
1641 event
= ftrace_find_event(entry
->type
);
1642 if (event
&& event
->hex
)
1643 event
->hex(s
, entry
, 0);
1645 SEQ_PUT_FIELD_RET(s
, newline
);
1647 return TRACE_TYPE_HANDLED
;
1650 static enum print_line_t
print_printk_msg_only(struct trace_iterator
*iter
)
1652 struct trace_seq
*s
= &iter
->seq
;
1653 struct trace_entry
*entry
= iter
->ent
;
1654 struct print_entry
*field
;
1657 trace_assign_type(field
, entry
);
1659 ret
= trace_seq_printf(s
, field
->buf
);
1661 return TRACE_TYPE_PARTIAL_LINE
;
1663 return TRACE_TYPE_HANDLED
;
1666 static enum print_line_t
print_bin_fmt(struct trace_iterator
*iter
)
1668 struct trace_seq
*s
= &iter
->seq
;
1669 struct trace_entry
*entry
;
1670 struct trace_event
*event
;
1674 SEQ_PUT_FIELD_RET(s
, entry
->pid
);
1675 SEQ_PUT_FIELD_RET(s
, entry
->cpu
);
1676 SEQ_PUT_FIELD_RET(s
, iter
->ts
);
1678 event
= ftrace_find_event(entry
->type
);
1679 if (event
&& event
->binary
)
1680 event
->binary(s
, entry
, 0);
1682 return TRACE_TYPE_HANDLED
;
1685 static int trace_empty(struct trace_iterator
*iter
)
1689 for_each_tracing_cpu(cpu
) {
1690 if (iter
->buffer_iter
[cpu
]) {
1691 if (!ring_buffer_iter_empty(iter
->buffer_iter
[cpu
]))
1694 if (!ring_buffer_empty_cpu(iter
->tr
->buffer
, cpu
))
1702 static enum print_line_t
print_trace_line(struct trace_iterator
*iter
)
1704 enum print_line_t ret
;
1706 if (iter
->trace
&& iter
->trace
->print_line
) {
1707 ret
= iter
->trace
->print_line(iter
);
1708 if (ret
!= TRACE_TYPE_UNHANDLED
)
1712 if (iter
->ent
->type
== TRACE_PRINT
&&
1713 trace_flags
& TRACE_ITER_PRINTK
&&
1714 trace_flags
& TRACE_ITER_PRINTK_MSGONLY
)
1715 return print_printk_msg_only(iter
);
1717 if (trace_flags
& TRACE_ITER_BIN
)
1718 return print_bin_fmt(iter
);
1720 if (trace_flags
& TRACE_ITER_HEX
)
1721 return print_hex_fmt(iter
);
1723 if (trace_flags
& TRACE_ITER_RAW
)
1724 return print_raw_fmt(iter
);
1726 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
)
1727 return print_lat_fmt(iter
, iter
->idx
, iter
->cpu
);
1729 return print_trace_fmt(iter
);
1732 static int s_show(struct seq_file
*m
, void *v
)
1734 struct trace_iterator
*iter
= v
;
1736 if (iter
->ent
== NULL
) {
1738 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
1741 if (iter
->trace
&& iter
->trace
->print_header
)
1742 iter
->trace
->print_header(m
);
1743 else if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
1744 /* print nothing if the buffers are empty */
1745 if (trace_empty(iter
))
1747 print_trace_header(m
, iter
);
1748 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1749 print_lat_help_header(m
);
1751 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1752 print_func_help_header(m
);
1755 print_trace_line(iter
);
1756 trace_print_seq(m
, &iter
->seq
);
1762 static struct seq_operations tracer_seq_ops
= {
1769 static struct trace_iterator
*
1770 __tracing_open(struct inode
*inode
, struct file
*file
, int *ret
)
1772 struct trace_iterator
*iter
;
1776 if (tracing_disabled
) {
1781 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
1787 mutex_lock(&trace_types_lock
);
1788 if (current_trace
&& current_trace
->print_max
)
1791 iter
->tr
= inode
->i_private
;
1792 iter
->trace
= current_trace
;
1795 /* Notify the tracer early; before we stop tracing. */
1796 if (iter
->trace
&& iter
->trace
->open
)
1797 iter
->trace
->open(iter
);
1799 /* Annotate start of buffers if we had overruns */
1800 if (ring_buffer_overruns(iter
->tr
->buffer
))
1801 iter
->iter_flags
|= TRACE_FILE_ANNOTATE
;
1804 for_each_tracing_cpu(cpu
) {
1806 iter
->buffer_iter
[cpu
] =
1807 ring_buffer_read_start(iter
->tr
->buffer
, cpu
);
1809 if (!iter
->buffer_iter
[cpu
])
1813 /* TODO stop tracer */
1814 *ret
= seq_open(file
, &tracer_seq_ops
);
1818 m
= file
->private_data
;
1821 /* stop the trace while dumping */
1824 mutex_unlock(&trace_types_lock
);
1830 for_each_tracing_cpu(cpu
) {
1831 if (iter
->buffer_iter
[cpu
])
1832 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
1834 mutex_unlock(&trace_types_lock
);
1837 return ERR_PTR(-ENOMEM
);
1840 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
1842 if (tracing_disabled
)
1845 filp
->private_data
= inode
->i_private
;
1849 int tracing_release(struct inode
*inode
, struct file
*file
)
1851 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
1852 struct trace_iterator
*iter
= m
->private;
1855 mutex_lock(&trace_types_lock
);
1856 for_each_tracing_cpu(cpu
) {
1857 if (iter
->buffer_iter
[cpu
])
1858 ring_buffer_read_finish(iter
->buffer_iter
[cpu
]);
1861 if (iter
->trace
&& iter
->trace
->close
)
1862 iter
->trace
->close(iter
);
1864 /* reenable tracing if it was previously enabled */
1866 mutex_unlock(&trace_types_lock
);
1868 seq_release(inode
, file
);
1873 static int tracing_open(struct inode
*inode
, struct file
*file
)
1877 __tracing_open(inode
, file
, &ret
);
1882 static int tracing_lt_open(struct inode
*inode
, struct file
*file
)
1884 struct trace_iterator
*iter
;
1887 iter
= __tracing_open(inode
, file
, &ret
);
1890 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
1897 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1899 struct tracer
*t
= m
->private;
1911 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
1913 struct tracer
*t
= m
->private;
1916 mutex_lock(&trace_types_lock
);
1917 for (; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
1923 static void t_stop(struct seq_file
*m
, void *p
)
1925 mutex_unlock(&trace_types_lock
);
1928 static int t_show(struct seq_file
*m
, void *v
)
1930 struct tracer
*t
= v
;
1935 seq_printf(m
, "%s", t
->name
);
1944 static struct seq_operations show_traces_seq_ops
= {
1951 static int show_traces_open(struct inode
*inode
, struct file
*file
)
1955 if (tracing_disabled
)
1958 ret
= seq_open(file
, &show_traces_seq_ops
);
1960 struct seq_file
*m
= file
->private_data
;
1961 m
->private = trace_types
;
1967 static struct file_operations tracing_fops
= {
1968 .open
= tracing_open
,
1970 .llseek
= seq_lseek
,
1971 .release
= tracing_release
,
1974 static struct file_operations tracing_lt_fops
= {
1975 .open
= tracing_lt_open
,
1977 .llseek
= seq_lseek
,
1978 .release
= tracing_release
,
1981 static struct file_operations show_traces_fops
= {
1982 .open
= show_traces_open
,
1984 .release
= seq_release
,
1988 * Only trace on a CPU if the bitmask is set:
1990 static cpumask_t tracing_cpumask
= CPU_MASK_ALL
;
1993 * When tracing/tracing_cpu_mask is modified then this holds
1994 * the new bitmask we are about to install:
1996 static cpumask_t tracing_cpumask_new
;
1999 * The tracer itself will not take this lock, but still we want
2000 * to provide a consistent cpumask to user-space:
2002 static DEFINE_MUTEX(tracing_cpumask_update_lock
);
2005 * Temporary storage for the character representation of the
2006 * CPU bitmask (and one more byte for the newline):
2008 static char mask_str
[NR_CPUS
+ 1];
2011 tracing_cpumask_read(struct file
*filp
, char __user
*ubuf
,
2012 size_t count
, loff_t
*ppos
)
2016 mutex_lock(&tracing_cpumask_update_lock
);
2018 len
= cpumask_scnprintf(mask_str
, count
, tracing_cpumask
);
2019 if (count
- len
< 2) {
2023 len
+= sprintf(mask_str
+ len
, "\n");
2024 count
= simple_read_from_buffer(ubuf
, count
, ppos
, mask_str
, NR_CPUS
+1);
2027 mutex_unlock(&tracing_cpumask_update_lock
);
2033 tracing_cpumask_write(struct file
*filp
, const char __user
*ubuf
,
2034 size_t count
, loff_t
*ppos
)
2038 mutex_lock(&tracing_cpumask_update_lock
);
2039 err
= cpumask_parse_user(ubuf
, count
, tracing_cpumask_new
);
2043 local_irq_disable();
2044 __raw_spin_lock(&ftrace_max_lock
);
2045 for_each_tracing_cpu(cpu
) {
2047 * Increase/decrease the disabled counter if we are
2048 * about to flip a bit in the cpumask:
2050 if (cpu_isset(cpu
, tracing_cpumask
) &&
2051 !cpu_isset(cpu
, tracing_cpumask_new
)) {
2052 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
2054 if (!cpu_isset(cpu
, tracing_cpumask
) &&
2055 cpu_isset(cpu
, tracing_cpumask_new
)) {
2056 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
2059 __raw_spin_unlock(&ftrace_max_lock
);
2062 tracing_cpumask
= tracing_cpumask_new
;
2064 mutex_unlock(&tracing_cpumask_update_lock
);
2069 mutex_unlock(&tracing_cpumask_update_lock
);
2074 static struct file_operations tracing_cpumask_fops
= {
2075 .open
= tracing_open_generic
,
2076 .read
= tracing_cpumask_read
,
2077 .write
= tracing_cpumask_write
,
2081 tracing_trace_options_read(struct file
*filp
, char __user
*ubuf
,
2082 size_t cnt
, loff_t
*ppos
)
2088 u32 tracer_flags
= current_trace
->flags
->val
;
2089 struct tracer_opt
*trace_opts
= current_trace
->flags
->opts
;
2092 /* calulate max size */
2093 for (i
= 0; trace_options
[i
]; i
++) {
2094 len
+= strlen(trace_options
[i
]);
2095 len
+= 3; /* "no" and space */
2099 * Increase the size with names of options specific
2100 * of the current tracer.
2102 for (i
= 0; trace_opts
[i
].name
; i
++) {
2103 len
+= strlen(trace_opts
[i
].name
);
2104 len
+= 3; /* "no" and space */
2107 /* +2 for \n and \0 */
2108 buf
= kmalloc(len
+ 2, GFP_KERNEL
);
2112 for (i
= 0; trace_options
[i
]; i
++) {
2113 if (trace_flags
& (1 << i
))
2114 r
+= sprintf(buf
+ r
, "%s ", trace_options
[i
]);
2116 r
+= sprintf(buf
+ r
, "no%s ", trace_options
[i
]);
2119 for (i
= 0; trace_opts
[i
].name
; i
++) {
2120 if (tracer_flags
& trace_opts
[i
].bit
)
2121 r
+= sprintf(buf
+ r
, "%s ",
2122 trace_opts
[i
].name
);
2124 r
+= sprintf(buf
+ r
, "no%s ",
2125 trace_opts
[i
].name
);
2128 r
+= sprintf(buf
+ r
, "\n");
2129 WARN_ON(r
>= len
+ 2);
2131 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2138 /* Try to assign a tracer specific option */
2139 static int set_tracer_option(struct tracer
*trace
, char *cmp
, int neg
)
2141 struct tracer_flags
*trace_flags
= trace
->flags
;
2142 struct tracer_opt
*opts
= NULL
;
2146 for (i
= 0; trace_flags
->opts
[i
].name
; i
++) {
2147 opts
= &trace_flags
->opts
[i
];
2148 len
= strlen(opts
->name
);
2150 if (strncmp(cmp
, opts
->name
, len
) == 0) {
2151 ret
= trace
->set_flag(trace_flags
->val
,
2157 if (!trace_flags
->opts
[i
].name
)
2160 /* Refused to handle */
2165 trace_flags
->val
&= ~opts
->bit
;
2167 trace_flags
->val
|= opts
->bit
;
2173 tracing_trace_options_write(struct file
*filp
, const char __user
*ubuf
,
2174 size_t cnt
, loff_t
*ppos
)
2182 if (cnt
>= sizeof(buf
))
2185 if (copy_from_user(&buf
, ubuf
, cnt
))
2190 if (strncmp(buf
, "no", 2) == 0) {
2195 for (i
= 0; trace_options
[i
]; i
++) {
2196 int len
= strlen(trace_options
[i
]);
2198 if (strncmp(cmp
, trace_options
[i
], len
) == 0) {
2200 trace_flags
&= ~(1 << i
);
2202 trace_flags
|= (1 << i
);
2207 /* If no option could be set, test the specific tracer options */
2208 if (!trace_options
[i
]) {
2209 ret
= set_tracer_option(current_trace
, cmp
, neg
);
2219 static struct file_operations tracing_iter_fops
= {
2220 .open
= tracing_open_generic
,
2221 .read
= tracing_trace_options_read
,
2222 .write
= tracing_trace_options_write
,
2225 static const char readme_msg
[] =
2226 "tracing mini-HOWTO:\n\n"
2228 "# mount -t debugfs nodev /debug\n\n"
2229 "# cat /debug/tracing/available_tracers\n"
2230 "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
2231 "# cat /debug/tracing/current_tracer\n"
2233 "# echo sched_switch > /debug/tracing/current_tracer\n"
2234 "# cat /debug/tracing/current_tracer\n"
2236 "# cat /debug/tracing/trace_options\n"
2237 "noprint-parent nosym-offset nosym-addr noverbose\n"
2238 "# echo print-parent > /debug/tracing/trace_options\n"
2239 "# echo 1 > /debug/tracing/tracing_enabled\n"
2240 "# cat /debug/tracing/trace > /tmp/trace.txt\n"
2241 "echo 0 > /debug/tracing/tracing_enabled\n"
2245 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
2246 size_t cnt
, loff_t
*ppos
)
2248 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
2249 readme_msg
, strlen(readme_msg
));
2252 static struct file_operations tracing_readme_fops
= {
2253 .open
= tracing_open_generic
,
2254 .read
= tracing_readme_read
,
2258 tracing_ctrl_read(struct file
*filp
, char __user
*ubuf
,
2259 size_t cnt
, loff_t
*ppos
)
2264 r
= sprintf(buf
, "%u\n", tracer_enabled
);
2265 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2269 tracing_ctrl_write(struct file
*filp
, const char __user
*ubuf
,
2270 size_t cnt
, loff_t
*ppos
)
2272 struct trace_array
*tr
= filp
->private_data
;
2277 if (cnt
>= sizeof(buf
))
2280 if (copy_from_user(&buf
, ubuf
, cnt
))
2285 ret
= strict_strtoul(buf
, 10, &val
);
2291 mutex_lock(&trace_types_lock
);
2292 if (tracer_enabled
^ val
) {
2295 if (current_trace
->start
)
2296 current_trace
->start(tr
);
2301 if (current_trace
->stop
)
2302 current_trace
->stop(tr
);
2305 mutex_unlock(&trace_types_lock
);
2313 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
2314 size_t cnt
, loff_t
*ppos
)
2316 char buf
[max_tracer_type_len
+2];
2319 mutex_lock(&trace_types_lock
);
2321 r
= sprintf(buf
, "%s\n", current_trace
->name
);
2323 r
= sprintf(buf
, "\n");
2324 mutex_unlock(&trace_types_lock
);
2326 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2329 static int tracing_set_tracer(char *buf
)
2331 struct trace_array
*tr
= &global_trace
;
2335 mutex_lock(&trace_types_lock
);
2336 for (t
= trace_types
; t
; t
= t
->next
) {
2337 if (strcmp(t
->name
, buf
) == 0)
2344 if (t
== current_trace
)
2347 trace_branch_disable();
2348 if (current_trace
&& current_trace
->reset
)
2349 current_trace
->reset(tr
);
2357 init_tracer_stat(t
);
2359 trace_branch_enable(tr
);
2361 mutex_unlock(&trace_types_lock
);
2367 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
2368 size_t cnt
, loff_t
*ppos
)
2370 char buf
[max_tracer_type_len
+1];
2377 if (cnt
> max_tracer_type_len
)
2378 cnt
= max_tracer_type_len
;
2380 if (copy_from_user(&buf
, ubuf
, cnt
))
2385 /* strip ending whitespace. */
2386 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
2389 err
= tracing_set_tracer(buf
);
2399 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
2400 size_t cnt
, loff_t
*ppos
)
2402 unsigned long *ptr
= filp
->private_data
;
2406 r
= snprintf(buf
, sizeof(buf
), "%ld\n",
2407 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
2408 if (r
> sizeof(buf
))
2410 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2414 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
2415 size_t cnt
, loff_t
*ppos
)
2417 long *ptr
= filp
->private_data
;
2422 if (cnt
>= sizeof(buf
))
2425 if (copy_from_user(&buf
, ubuf
, cnt
))
2430 ret
= strict_strtoul(buf
, 10, &val
);
2439 static atomic_t tracing_reader
;
2441 static int tracing_open_pipe(struct inode
*inode
, struct file
*filp
)
2443 struct trace_iterator
*iter
;
2445 if (tracing_disabled
)
2448 /* We only allow for reader of the pipe */
2449 if (atomic_inc_return(&tracing_reader
) != 1) {
2450 atomic_dec(&tracing_reader
);
2454 /* create a buffer to store the information to pass to userspace */
2455 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2459 mutex_lock(&trace_types_lock
);
2461 /* trace pipe does not show start of buffer */
2462 cpus_setall(iter
->started
);
2464 iter
->tr
= &global_trace
;
2465 iter
->trace
= current_trace
;
2466 filp
->private_data
= iter
;
2468 if (iter
->trace
->pipe_open
)
2469 iter
->trace
->pipe_open(iter
);
2470 mutex_unlock(&trace_types_lock
);
2475 static int tracing_release_pipe(struct inode
*inode
, struct file
*file
)
2477 struct trace_iterator
*iter
= file
->private_data
;
2480 atomic_dec(&tracing_reader
);
2486 tracing_poll_pipe(struct file
*filp
, poll_table
*poll_table
)
2488 struct trace_iterator
*iter
= filp
->private_data
;
2490 if (trace_flags
& TRACE_ITER_BLOCK
) {
2492 * Always select as readable when in blocking mode
2494 return POLLIN
| POLLRDNORM
;
2496 if (!trace_empty(iter
))
2497 return POLLIN
| POLLRDNORM
;
2498 poll_wait(filp
, &trace_wait
, poll_table
);
2499 if (!trace_empty(iter
))
2500 return POLLIN
| POLLRDNORM
;
2510 tracing_read_pipe(struct file
*filp
, char __user
*ubuf
,
2511 size_t cnt
, loff_t
*ppos
)
2513 struct trace_iterator
*iter
= filp
->private_data
;
2516 /* return any leftover data */
2517 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
2521 trace_seq_reset(&iter
->seq
);
2523 mutex_lock(&trace_types_lock
);
2524 if (iter
->trace
->read
) {
2525 sret
= iter
->trace
->read(iter
, filp
, ubuf
, cnt
, ppos
);
2532 while (trace_empty(iter
)) {
2534 if ((filp
->f_flags
& O_NONBLOCK
)) {
2540 * This is a make-shift waitqueue. The reason we don't use
2541 * an actual wait queue is because:
2542 * 1) we only ever have one waiter
2543 * 2) the tracing, traces all functions, we don't want
2544 * the overhead of calling wake_up and friends
2545 * (and tracing them too)
2546 * Anyway, this is really very primitive wakeup.
2548 set_current_state(TASK_INTERRUPTIBLE
);
2549 iter
->tr
->waiter
= current
;
2551 mutex_unlock(&trace_types_lock
);
2553 /* sleep for 100 msecs, and try again. */
2554 schedule_timeout(HZ
/10);
2556 mutex_lock(&trace_types_lock
);
2558 iter
->tr
->waiter
= NULL
;
2560 if (signal_pending(current
)) {
2565 if (iter
->trace
!= current_trace
)
2569 * We block until we read something and tracing is disabled.
2570 * We still block if tracing is disabled, but we have never
2571 * read anything. This allows a user to cat this file, and
2572 * then enable tracing. But after we have read something,
2573 * we give an EOF when tracing is again disabled.
2575 * iter->pos will be 0 if we haven't read anything.
2577 if (!tracer_enabled
&& iter
->pos
)
2583 /* stop when tracing is finished */
2584 if (trace_empty(iter
))
2587 if (cnt
>= PAGE_SIZE
)
2588 cnt
= PAGE_SIZE
- 1;
2590 /* reset all but tr, trace, and overruns */
2591 memset(&iter
->seq
, 0,
2592 sizeof(struct trace_iterator
) -
2593 offsetof(struct trace_iterator
, seq
));
2596 while (find_next_entry_inc(iter
) != NULL
) {
2597 enum print_line_t ret
;
2598 int len
= iter
->seq
.len
;
2600 ret
= print_trace_line(iter
);
2601 if (ret
== TRACE_TYPE_PARTIAL_LINE
) {
2602 /* don't print partial lines */
2603 iter
->seq
.len
= len
;
2607 trace_consume(iter
);
2609 if (iter
->seq
.len
>= cnt
)
2613 /* Now copy what we have to the user */
2614 sret
= trace_seq_to_user(&iter
->seq
, ubuf
, cnt
);
2615 if (iter
->seq
.readpos
>= iter
->seq
.len
)
2616 trace_seq_reset(&iter
->seq
);
2619 * If there was nothing to send to user, inspite of consuming trace
2620 * entries, go back to wait for more entries.
2626 mutex_unlock(&trace_types_lock
);
2632 tracing_entries_read(struct file
*filp
, char __user
*ubuf
,
2633 size_t cnt
, loff_t
*ppos
)
2635 struct trace_array
*tr
= filp
->private_data
;
2639 r
= sprintf(buf
, "%lu\n", tr
->entries
>> 10);
2640 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2644 tracing_entries_write(struct file
*filp
, const char __user
*ubuf
,
2645 size_t cnt
, loff_t
*ppos
)
2651 if (cnt
>= sizeof(buf
))
2654 if (copy_from_user(&buf
, ubuf
, cnt
))
2659 ret
= strict_strtoul(buf
, 10, &val
);
2663 /* must have at least 1 entry */
2667 mutex_lock(&trace_types_lock
);
2671 /* disable all cpu buffers */
2672 for_each_tracing_cpu(cpu
) {
2673 if (global_trace
.data
[cpu
])
2674 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
2675 if (max_tr
.data
[cpu
])
2676 atomic_inc(&max_tr
.data
[cpu
]->disabled
);
2679 /* value is in KB */
2682 if (val
!= global_trace
.entries
) {
2683 ret
= ring_buffer_resize(global_trace
.buffer
, val
);
2689 ret
= ring_buffer_resize(max_tr
.buffer
, val
);
2693 r
= ring_buffer_resize(global_trace
.buffer
,
2694 global_trace
.entries
);
2696 /* AARGH! We are left with different
2697 * size max buffer!!!! */
2699 tracing_disabled
= 1;
2704 global_trace
.entries
= val
;
2709 /* If check pages failed, return ENOMEM */
2710 if (tracing_disabled
)
2713 for_each_tracing_cpu(cpu
) {
2714 if (global_trace
.data
[cpu
])
2715 atomic_dec(&global_trace
.data
[cpu
]->disabled
);
2716 if (max_tr
.data
[cpu
])
2717 atomic_dec(&max_tr
.data
[cpu
]->disabled
);
2721 max_tr
.entries
= global_trace
.entries
;
2722 mutex_unlock(&trace_types_lock
);
2727 static int mark_printk(const char *fmt
, ...)
2731 va_start(args
, fmt
);
2732 ret
= trace_vprintk(0, -1, fmt
, args
);
2738 tracing_mark_write(struct file
*filp
, const char __user
*ubuf
,
2739 size_t cnt
, loff_t
*fpos
)
2744 if (tracing_disabled
)
2747 if (cnt
> TRACE_BUF_SIZE
)
2748 cnt
= TRACE_BUF_SIZE
;
2750 buf
= kmalloc(cnt
+ 1, GFP_KERNEL
);
2754 if (copy_from_user(buf
, ubuf
, cnt
)) {
2759 /* Cut from the first nil or newline. */
2761 end
= strchr(buf
, '\n');
2765 cnt
= mark_printk("%s\n", buf
);
2772 static struct file_operations tracing_max_lat_fops
= {
2773 .open
= tracing_open_generic
,
2774 .read
= tracing_max_lat_read
,
2775 .write
= tracing_max_lat_write
,
2778 static struct file_operations tracing_ctrl_fops
= {
2779 .open
= tracing_open_generic
,
2780 .read
= tracing_ctrl_read
,
2781 .write
= tracing_ctrl_write
,
2784 static struct file_operations set_tracer_fops
= {
2785 .open
= tracing_open_generic
,
2786 .read
= tracing_set_trace_read
,
2787 .write
= tracing_set_trace_write
,
2790 static struct file_operations tracing_pipe_fops
= {
2791 .open
= tracing_open_pipe
,
2792 .poll
= tracing_poll_pipe
,
2793 .read
= tracing_read_pipe
,
2794 .release
= tracing_release_pipe
,
2797 static struct file_operations tracing_entries_fops
= {
2798 .open
= tracing_open_generic
,
2799 .read
= tracing_entries_read
,
2800 .write
= tracing_entries_write
,
2803 static struct file_operations tracing_mark_fops
= {
2804 .open
= tracing_open_generic
,
2805 .write
= tracing_mark_write
,
2808 #ifdef CONFIG_DYNAMIC_FTRACE
2810 int __weak
ftrace_arch_read_dyn_info(char *buf
, int size
)
2816 tracing_read_dyn_info(struct file
*filp
, char __user
*ubuf
,
2817 size_t cnt
, loff_t
*ppos
)
2819 static char ftrace_dyn_info_buffer
[1024];
2820 static DEFINE_MUTEX(dyn_info_mutex
);
2821 unsigned long *p
= filp
->private_data
;
2822 char *buf
= ftrace_dyn_info_buffer
;
2823 int size
= ARRAY_SIZE(ftrace_dyn_info_buffer
);
2826 mutex_lock(&dyn_info_mutex
);
2827 r
= sprintf(buf
, "%ld ", *p
);
2829 r
+= ftrace_arch_read_dyn_info(buf
+r
, (size
-1)-r
);
2832 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2834 mutex_unlock(&dyn_info_mutex
);
2839 static struct file_operations tracing_dyn_info_fops
= {
2840 .open
= tracing_open_generic
,
2841 .read
= tracing_read_dyn_info
,
2845 static struct dentry
*d_tracer
;
2847 struct dentry
*tracing_init_dentry(void)
2854 d_tracer
= debugfs_create_dir("tracing", NULL
);
2856 if (!d_tracer
&& !once
) {
2858 pr_warning("Could not create debugfs directory 'tracing'\n");
2865 #ifdef CONFIG_FTRACE_SELFTEST
2866 /* Let selftest have access to static functions in this file */
2867 #include "trace_selftest.c"
2870 static __init
int tracer_init_debugfs(void)
2872 struct dentry
*d_tracer
;
2873 struct dentry
*entry
;
2875 d_tracer
= tracing_init_dentry();
2877 entry
= debugfs_create_file("tracing_enabled", 0644, d_tracer
,
2878 &global_trace
, &tracing_ctrl_fops
);
2880 pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
2882 entry
= debugfs_create_file("trace_options", 0644, d_tracer
,
2883 NULL
, &tracing_iter_fops
);
2885 pr_warning("Could not create debugfs 'trace_options' entry\n");
2887 entry
= debugfs_create_file("tracing_cpumask", 0644, d_tracer
,
2888 NULL
, &tracing_cpumask_fops
);
2890 pr_warning("Could not create debugfs 'tracing_cpumask' entry\n");
2892 entry
= debugfs_create_file("latency_trace", 0444, d_tracer
,
2893 &global_trace
, &tracing_lt_fops
);
2895 pr_warning("Could not create debugfs 'latency_trace' entry\n");
2897 entry
= debugfs_create_file("trace", 0444, d_tracer
,
2898 &global_trace
, &tracing_fops
);
2900 pr_warning("Could not create debugfs 'trace' entry\n");
2902 entry
= debugfs_create_file("available_tracers", 0444, d_tracer
,
2903 &global_trace
, &show_traces_fops
);
2905 pr_warning("Could not create debugfs 'available_tracers' entry\n");
2907 entry
= debugfs_create_file("current_tracer", 0444, d_tracer
,
2908 &global_trace
, &set_tracer_fops
);
2910 pr_warning("Could not create debugfs 'current_tracer' entry\n");
2912 entry
= debugfs_create_file("tracing_max_latency", 0644, d_tracer
,
2913 &tracing_max_latency
,
2914 &tracing_max_lat_fops
);
2916 pr_warning("Could not create debugfs "
2917 "'tracing_max_latency' entry\n");
2919 entry
= debugfs_create_file("tracing_thresh", 0644, d_tracer
,
2920 &tracing_thresh
, &tracing_max_lat_fops
);
2922 pr_warning("Could not create debugfs "
2923 "'tracing_thresh' entry\n");
2924 entry
= debugfs_create_file("README", 0644, d_tracer
,
2925 NULL
, &tracing_readme_fops
);
2927 pr_warning("Could not create debugfs 'README' entry\n");
2929 entry
= debugfs_create_file("trace_pipe", 0644, d_tracer
,
2930 NULL
, &tracing_pipe_fops
);
2932 pr_warning("Could not create debugfs "
2933 "'trace_pipe' entry\n");
2935 entry
= debugfs_create_file("buffer_size_kb", 0644, d_tracer
,
2936 &global_trace
, &tracing_entries_fops
);
2938 pr_warning("Could not create debugfs "
2939 "'buffer_size_kb' entry\n");
2941 entry
= debugfs_create_file("trace_marker", 0220, d_tracer
,
2942 NULL
, &tracing_mark_fops
);
2944 pr_warning("Could not create debugfs "
2945 "'trace_marker' entry\n");
2947 #ifdef CONFIG_DYNAMIC_FTRACE
2948 entry
= debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
2949 &ftrace_update_tot_cnt
,
2950 &tracing_dyn_info_fops
);
2952 pr_warning("Could not create debugfs "
2953 "'dyn_ftrace_total_info' entry\n");
2955 #ifdef CONFIG_SYSPROF_TRACER
2956 init_tracer_sysprof_debugfs(d_tracer
);
2961 int trace_vprintk(unsigned long ip
, int depth
, const char *fmt
, va_list args
)
2963 static DEFINE_SPINLOCK(trace_buf_lock
);
2964 static char trace_buf
[TRACE_BUF_SIZE
];
2966 struct ring_buffer_event
*event
;
2967 struct trace_array
*tr
= &global_trace
;
2968 struct trace_array_cpu
*data
;
2969 int cpu
, len
= 0, size
, pc
;
2970 struct print_entry
*entry
;
2971 unsigned long irq_flags
;
2973 if (tracing_disabled
|| tracing_selftest_running
)
2976 pc
= preempt_count();
2977 preempt_disable_notrace();
2978 cpu
= raw_smp_processor_id();
2979 data
= tr
->data
[cpu
];
2981 if (unlikely(atomic_read(&data
->disabled
)))
2984 pause_graph_tracing();
2985 spin_lock_irqsave(&trace_buf_lock
, irq_flags
);
2986 len
= vsnprintf(trace_buf
, TRACE_BUF_SIZE
, fmt
, args
);
2988 len
= min(len
, TRACE_BUF_SIZE
-1);
2991 size
= sizeof(*entry
) + len
+ 1;
2992 event
= ring_buffer_lock_reserve(tr
->buffer
, size
, &irq_flags
);
2995 entry
= ring_buffer_event_data(event
);
2996 tracing_generic_entry_update(&entry
->ent
, irq_flags
, pc
);
2997 entry
->ent
.type
= TRACE_PRINT
;
2999 entry
->depth
= depth
;
3001 memcpy(&entry
->buf
, trace_buf
, len
);
3002 entry
->buf
[len
] = 0;
3003 ring_buffer_unlock_commit(tr
->buffer
, event
, irq_flags
);
3006 spin_unlock_irqrestore(&trace_buf_lock
, irq_flags
);
3007 unpause_graph_tracing();
3009 preempt_enable_notrace();
3013 EXPORT_SYMBOL_GPL(trace_vprintk
);
3015 int __ftrace_printk(unsigned long ip
, const char *fmt
, ...)
3020 if (!(trace_flags
& TRACE_ITER_PRINTK
))
3024 ret
= trace_vprintk(ip
, task_curr_ret_stack(current
), fmt
, ap
);
3028 EXPORT_SYMBOL_GPL(__ftrace_printk
);
3030 static int trace_panic_handler(struct notifier_block
*this,
3031 unsigned long event
, void *unused
)
3033 if (ftrace_dump_on_oops
)
3038 static struct notifier_block trace_panic_notifier
= {
3039 .notifier_call
= trace_panic_handler
,
3041 .priority
= 150 /* priority: INT_MAX >= x >= 0 */
3044 static int trace_die_handler(struct notifier_block
*self
,
3050 if (ftrace_dump_on_oops
)
3059 static struct notifier_block trace_die_notifier
= {
3060 .notifier_call
= trace_die_handler
,
3065 * printk is set to max of 1024, we really don't need it that big.
3066 * Nothing should be printing 1000 characters anyway.
3068 #define TRACE_MAX_PRINT 1000
3071 * Define here KERN_TRACE so that we have one place to modify
3072 * it if we decide to change what log level the ftrace dump
3075 #define KERN_TRACE KERN_INFO
3078 trace_printk_seq(struct trace_seq
*s
)
3080 /* Probably should print a warning here. */
3084 /* should be zero ended, but we are paranoid. */
3085 s
->buffer
[s
->len
] = 0;
3087 printk(KERN_TRACE
"%s", s
->buffer
);
3092 void ftrace_dump(void)
3094 static DEFINE_SPINLOCK(ftrace_dump_lock
);
3095 /* use static because iter can be a bit big for the stack */
3096 static struct trace_iterator iter
;
3097 static cpumask_t mask
;
3098 static int dump_ran
;
3099 unsigned long flags
;
3103 spin_lock_irqsave(&ftrace_dump_lock
, flags
);
3109 /* No turning back! */
3112 for_each_tracing_cpu(cpu
) {
3113 atomic_inc(&global_trace
.data
[cpu
]->disabled
);
3116 /* don't look at user memory in panic mode */
3117 trace_flags
&= ~TRACE_ITER_SYM_USEROBJ
;
3119 printk(KERN_TRACE
"Dumping ftrace buffer:\n");
3121 iter
.tr
= &global_trace
;
3122 iter
.trace
= current_trace
;
3125 * We need to stop all tracing on all CPUS to read the
3126 * the next buffer. This is a bit expensive, but is
3127 * not done often. We fill all what we can read,
3128 * and then release the locks again.
3133 while (!trace_empty(&iter
)) {
3136 printk(KERN_TRACE
"---------------------------------\n");
3140 /* reset all but tr, trace, and overruns */
3141 memset(&iter
.seq
, 0,
3142 sizeof(struct trace_iterator
) -
3143 offsetof(struct trace_iterator
, seq
));
3144 iter
.iter_flags
|= TRACE_FILE_LAT_FMT
;
3147 if (find_next_entry_inc(&iter
) != NULL
) {
3148 print_trace_line(&iter
);
3149 trace_consume(&iter
);
3152 trace_printk_seq(&iter
.seq
);
3156 printk(KERN_TRACE
" (ftrace buffer empty)\n");
3158 printk(KERN_TRACE
"---------------------------------\n");
3161 spin_unlock_irqrestore(&ftrace_dump_lock
, flags
);
3164 __init
static int tracer_alloc_buffers(void)
3166 struct trace_array_cpu
*data
;
3169 /* TODO: make the number of buffers hot pluggable with CPUS */
3170 tracing_buffer_mask
= cpu_possible_map
;
3172 global_trace
.buffer
= ring_buffer_alloc(trace_buf_size
,
3173 TRACE_BUFFER_FLAGS
);
3174 if (!global_trace
.buffer
) {
3175 printk(KERN_ERR
"tracer: failed to allocate ring buffer!\n");
3179 global_trace
.entries
= ring_buffer_size(global_trace
.buffer
);
3181 #ifdef CONFIG_TRACER_MAX_TRACE
3182 max_tr
.buffer
= ring_buffer_alloc(trace_buf_size
,
3183 TRACE_BUFFER_FLAGS
);
3184 if (!max_tr
.buffer
) {
3185 printk(KERN_ERR
"tracer: failed to allocate max ring buffer!\n");
3187 ring_buffer_free(global_trace
.buffer
);
3190 max_tr
.entries
= ring_buffer_size(max_tr
.buffer
);
3191 WARN_ON(max_tr
.entries
!= global_trace
.entries
);
3194 /* Allocate the first page for all buffers */
3195 for_each_tracing_cpu(i
) {
3196 data
= global_trace
.data
[i
] = &per_cpu(global_trace_cpu
, i
);
3197 max_tr
.data
[i
] = &per_cpu(max_data
, i
);
3200 trace_init_cmdlines();
3202 register_tracer(&nop_trace
);
3203 #ifdef CONFIG_BOOT_TRACER
3204 register_tracer(&boot_tracer
);
3205 current_trace
= &boot_tracer
;
3206 current_trace
->init(&global_trace
);
3208 current_trace
= &nop_trace
;
3210 init_tracer_stat(current_trace
);
3211 /* All seems OK, enable tracing */
3212 tracing_disabled
= 0;
3214 atomic_notifier_chain_register(&panic_notifier_list
,
3215 &trace_panic_notifier
);
3217 register_die_notifier(&trace_die_notifier
);
3221 early_initcall(tracer_alloc_buffers
);
3222 fs_initcall(tracer_init_debugfs
);