2 * Infrastructure for profiling code inserted by 'gcc -pg'.
4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
7 * Originally ported from the -rt patch by:
8 * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
10 * Based on code in the latency_tracer, that is:
12 * Copyright (C) 2004-2006 Ingo Molnar
13 * Copyright (C) 2004 William Lee Irwin III
16 #include <linux/stop_machine.h>
17 #include <linux/clocksource.h>
18 #include <linux/kallsyms.h>
19 #include <linux/seq_file.h>
20 #include <linux/suspend.h>
21 #include <linux/debugfs.h>
22 #include <linux/hardirq.h>
23 #include <linux/kthread.h>
24 #include <linux/uaccess.h>
25 #include <linux/module.h>
26 #include <linux/ftrace.h>
27 #include <linux/sysctl.h>
28 #include <linux/slab.h>
29 #include <linux/ctype.h>
30 #include <linux/list.h>
31 #include <linux/hash.h>
32 #include <linux/rcupdate.h>
34 #include <trace/events/sched.h>
36 #include <asm/setup.h>
38 #include "trace_output.h"
39 #include "trace_stat.h"
41 #define FTRACE_WARN_ON(cond) \
49 #define FTRACE_WARN_ON_ONCE(cond) \
52 if (WARN_ON_ONCE(___r)) \
57 /* hash bits for specific function selection */
58 #define FTRACE_HASH_BITS 7
59 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
60 #define FTRACE_HASH_DEFAULT_BITS 10
61 #define FTRACE_HASH_MAX_BITS 12
63 /* ftrace_enabled is a method to turn ftrace on or off */
64 int ftrace_enabled __read_mostly
;
65 static int last_ftrace_enabled
;
67 /* Quick disabling of function tracer. */
68 int function_trace_stop
;
70 /* List for set_ftrace_pid's pids. */
71 LIST_HEAD(ftrace_pids
);
73 struct list_head list
;
78 * ftrace_disabled is set when an anomaly is discovered.
79 * ftrace_disabled is much stronger than ftrace_enabled.
81 static int ftrace_disabled __read_mostly
;
83 static DEFINE_MUTEX(ftrace_lock
);
85 static struct ftrace_ops ftrace_list_end __read_mostly
= {
89 static struct ftrace_ops
*ftrace_global_list __read_mostly
= &ftrace_list_end
;
90 static struct ftrace_ops
*ftrace_ops_list __read_mostly
= &ftrace_list_end
;
91 ftrace_func_t ftrace_trace_function __read_mostly
= ftrace_stub
;
92 static ftrace_func_t __ftrace_trace_function_delay __read_mostly
= ftrace_stub
;
93 ftrace_func_t __ftrace_trace_function __read_mostly
= ftrace_stub
;
94 ftrace_func_t ftrace_pid_function __read_mostly
= ftrace_stub
;
95 static struct ftrace_ops global_ops
;
98 ftrace_ops_list_func(unsigned long ip
, unsigned long parent_ip
);
101 * Traverse the ftrace_global_list, invoking all entries. The reason that we
102 * can use rcu_dereference_raw() is that elements removed from this list
103 * are simply leaked, so there is no need to interact with a grace-period
104 * mechanism. The rcu_dereference_raw() calls are needed to handle
105 * concurrent insertions into the ftrace_global_list.
107 * Silly Alpha and silly pointer-speculation compiler optimizations!
109 static void ftrace_global_list_func(unsigned long ip
,
110 unsigned long parent_ip
)
112 struct ftrace_ops
*op
;
114 if (unlikely(trace_recursion_test(TRACE_GLOBAL_BIT
)))
117 trace_recursion_set(TRACE_GLOBAL_BIT
);
118 op
= rcu_dereference_raw(ftrace_global_list
); /*see above*/
119 while (op
!= &ftrace_list_end
) {
120 op
->func(ip
, parent_ip
);
121 op
= rcu_dereference_raw(op
->next
); /*see above*/
123 trace_recursion_clear(TRACE_GLOBAL_BIT
);
126 static void ftrace_pid_func(unsigned long ip
, unsigned long parent_ip
)
128 if (!test_tsk_trace_trace(current
))
131 ftrace_pid_function(ip
, parent_ip
);
134 static void set_ftrace_pid_function(ftrace_func_t func
)
136 /* do not set ftrace_pid_function to itself! */
137 if (func
!= ftrace_pid_func
)
138 ftrace_pid_function
= func
;
142 * clear_ftrace_function - reset the ftrace function
144 * This NULLs the ftrace function and in essence stops
145 * tracing. There may be lag
147 void clear_ftrace_function(void)
149 ftrace_trace_function
= ftrace_stub
;
150 __ftrace_trace_function
= ftrace_stub
;
151 __ftrace_trace_function_delay
= ftrace_stub
;
152 ftrace_pid_function
= ftrace_stub
;
155 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
157 * For those archs that do not test ftrace_trace_stop in their
158 * mcount call site, we need to do it from C.
160 static void ftrace_test_stop_func(unsigned long ip
, unsigned long parent_ip
)
162 if (function_trace_stop
)
165 __ftrace_trace_function(ip
, parent_ip
);
169 static void update_global_ops(void)
174 * If there's only one function registered, then call that
175 * function directly. Otherwise, we need to iterate over the
176 * registered callers.
178 if (ftrace_global_list
== &ftrace_list_end
||
179 ftrace_global_list
->next
== &ftrace_list_end
)
180 func
= ftrace_global_list
->func
;
182 func
= ftrace_global_list_func
;
184 /* If we filter on pids, update to use the pid function */
185 if (!list_empty(&ftrace_pids
)) {
186 set_ftrace_pid_function(func
);
187 func
= ftrace_pid_func
;
190 global_ops
.func
= func
;
193 static void update_ftrace_function(void)
200 * If we are at the end of the list and this ops is
201 * not dynamic, then have the mcount trampoline call
202 * the function directly
204 if (ftrace_ops_list
== &ftrace_list_end
||
205 (ftrace_ops_list
->next
== &ftrace_list_end
&&
206 !(ftrace_ops_list
->flags
& FTRACE_OPS_FL_DYNAMIC
)))
207 func
= ftrace_ops_list
->func
;
209 func
= ftrace_ops_list_func
;
211 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
212 ftrace_trace_function
= func
;
214 #ifdef CONFIG_DYNAMIC_FTRACE
215 /* do not update till all functions have been modified */
216 __ftrace_trace_function_delay
= func
;
218 __ftrace_trace_function
= func
;
220 ftrace_trace_function
= ftrace_test_stop_func
;
224 static void add_ftrace_ops(struct ftrace_ops
**list
, struct ftrace_ops
*ops
)
228 * We are entering ops into the list but another
229 * CPU might be walking that list. We need to make sure
230 * the ops->next pointer is valid before another CPU sees
231 * the ops pointer included into the list.
233 rcu_assign_pointer(*list
, ops
);
236 static int remove_ftrace_ops(struct ftrace_ops
**list
, struct ftrace_ops
*ops
)
238 struct ftrace_ops
**p
;
241 * If we are removing the last function, then simply point
242 * to the ftrace_stub.
244 if (*list
== ops
&& ops
->next
== &ftrace_list_end
) {
245 *list
= &ftrace_list_end
;
249 for (p
= list
; *p
!= &ftrace_list_end
; p
= &(*p
)->next
)
260 static int __register_ftrace_function(struct ftrace_ops
*ops
)
265 if (FTRACE_WARN_ON(ops
== &global_ops
))
268 if (WARN_ON(ops
->flags
& FTRACE_OPS_FL_ENABLED
))
271 if (!core_kernel_data((unsigned long)ops
))
272 ops
->flags
|= FTRACE_OPS_FL_DYNAMIC
;
274 if (ops
->flags
& FTRACE_OPS_FL_GLOBAL
) {
275 int first
= ftrace_global_list
== &ftrace_list_end
;
276 add_ftrace_ops(&ftrace_global_list
, ops
);
277 ops
->flags
|= FTRACE_OPS_FL_ENABLED
;
279 add_ftrace_ops(&ftrace_ops_list
, &global_ops
);
281 add_ftrace_ops(&ftrace_ops_list
, ops
);
284 update_ftrace_function();
289 static int __unregister_ftrace_function(struct ftrace_ops
*ops
)
296 if (WARN_ON(!(ops
->flags
& FTRACE_OPS_FL_ENABLED
)))
299 if (FTRACE_WARN_ON(ops
== &global_ops
))
302 if (ops
->flags
& FTRACE_OPS_FL_GLOBAL
) {
303 ret
= remove_ftrace_ops(&ftrace_global_list
, ops
);
304 if (!ret
&& ftrace_global_list
== &ftrace_list_end
)
305 ret
= remove_ftrace_ops(&ftrace_ops_list
, &global_ops
);
307 ops
->flags
&= ~FTRACE_OPS_FL_ENABLED
;
309 ret
= remove_ftrace_ops(&ftrace_ops_list
, ops
);
315 update_ftrace_function();
318 * Dynamic ops may be freed, we must make sure that all
319 * callers are done before leaving this function.
321 if (ops
->flags
& FTRACE_OPS_FL_DYNAMIC
)
327 static void ftrace_update_pid_func(void)
329 /* Only do something if we are tracing something */
330 if (ftrace_trace_function
== ftrace_stub
)
333 update_ftrace_function();
336 #ifdef CONFIG_FUNCTION_PROFILER
337 struct ftrace_profile
{
338 struct hlist_node node
;
340 unsigned long counter
;
341 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
342 unsigned long long time
;
343 unsigned long long time_squared
;
347 struct ftrace_profile_page
{
348 struct ftrace_profile_page
*next
;
350 struct ftrace_profile records
[];
353 struct ftrace_profile_stat
{
355 struct hlist_head
*hash
;
356 struct ftrace_profile_page
*pages
;
357 struct ftrace_profile_page
*start
;
358 struct tracer_stat stat
;
361 #define PROFILE_RECORDS_SIZE \
362 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
364 #define PROFILES_PER_PAGE \
365 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
367 static int ftrace_profile_bits __read_mostly
;
368 static int ftrace_profile_enabled __read_mostly
;
370 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
371 static DEFINE_MUTEX(ftrace_profile_lock
);
373 static DEFINE_PER_CPU(struct ftrace_profile_stat
, ftrace_profile_stats
);
375 #define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
378 function_stat_next(void *v
, int idx
)
380 struct ftrace_profile
*rec
= v
;
381 struct ftrace_profile_page
*pg
;
383 pg
= (struct ftrace_profile_page
*)((unsigned long)rec
& PAGE_MASK
);
389 if ((void *)rec
>= (void *)&pg
->records
[pg
->index
]) {
393 rec
= &pg
->records
[0];
401 static void *function_stat_start(struct tracer_stat
*trace
)
403 struct ftrace_profile_stat
*stat
=
404 container_of(trace
, struct ftrace_profile_stat
, stat
);
406 if (!stat
|| !stat
->start
)
409 return function_stat_next(&stat
->start
->records
[0], 0);
412 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
413 /* function graph compares on total time */
414 static int function_stat_cmp(void *p1
, void *p2
)
416 struct ftrace_profile
*a
= p1
;
417 struct ftrace_profile
*b
= p2
;
419 if (a
->time
< b
->time
)
421 if (a
->time
> b
->time
)
427 /* not function graph compares against hits */
428 static int function_stat_cmp(void *p1
, void *p2
)
430 struct ftrace_profile
*a
= p1
;
431 struct ftrace_profile
*b
= p2
;
433 if (a
->counter
< b
->counter
)
435 if (a
->counter
> b
->counter
)
442 static int function_stat_headers(struct seq_file
*m
)
444 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
445 seq_printf(m
, " Function "
448 "--- ---- --- ---\n");
450 seq_printf(m
, " Function Hit\n"
456 static int function_stat_show(struct seq_file
*m
, void *v
)
458 struct ftrace_profile
*rec
= v
;
459 char str
[KSYM_SYMBOL_LEN
];
461 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
462 static struct trace_seq s
;
463 unsigned long long avg
;
464 unsigned long long stddev
;
466 mutex_lock(&ftrace_profile_lock
);
468 /* we raced with function_profile_reset() */
469 if (unlikely(rec
->counter
== 0)) {
474 kallsyms_lookup(rec
->ip
, NULL
, NULL
, NULL
, str
);
475 seq_printf(m
, " %-30.30s %10lu", str
, rec
->counter
);
477 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
480 do_div(avg
, rec
->counter
);
482 /* Sample standard deviation (s^2) */
483 if (rec
->counter
<= 1)
486 stddev
= rec
->time_squared
- rec
->counter
* avg
* avg
;
488 * Divide only 1000 for ns^2 -> us^2 conversion.
489 * trace_print_graph_duration will divide 1000 again.
491 do_div(stddev
, (rec
->counter
- 1) * 1000);
495 trace_print_graph_duration(rec
->time
, &s
);
496 trace_seq_puts(&s
, " ");
497 trace_print_graph_duration(avg
, &s
);
498 trace_seq_puts(&s
, " ");
499 trace_print_graph_duration(stddev
, &s
);
500 trace_print_seq(m
, &s
);
504 mutex_unlock(&ftrace_profile_lock
);
509 static void ftrace_profile_reset(struct ftrace_profile_stat
*stat
)
511 struct ftrace_profile_page
*pg
;
513 pg
= stat
->pages
= stat
->start
;
516 memset(pg
->records
, 0, PROFILE_RECORDS_SIZE
);
521 memset(stat
->hash
, 0,
522 FTRACE_PROFILE_HASH_SIZE
* sizeof(struct hlist_head
));
525 int ftrace_profile_pages_init(struct ftrace_profile_stat
*stat
)
527 struct ftrace_profile_page
*pg
;
532 /* If we already allocated, do nothing */
536 stat
->pages
= (void *)get_zeroed_page(GFP_KERNEL
);
540 #ifdef CONFIG_DYNAMIC_FTRACE
541 functions
= ftrace_update_tot_cnt
;
544 * We do not know the number of functions that exist because
545 * dynamic tracing is what counts them. With past experience
546 * we have around 20K functions. That should be more than enough.
547 * It is highly unlikely we will execute every function in
553 pg
= stat
->start
= stat
->pages
;
555 pages
= DIV_ROUND_UP(functions
, PROFILES_PER_PAGE
);
557 for (i
= 0; i
< pages
; i
++) {
558 pg
->next
= (void *)get_zeroed_page(GFP_KERNEL
);
569 unsigned long tmp
= (unsigned long)pg
;
575 free_page((unsigned long)stat
->pages
);
582 static int ftrace_profile_init_cpu(int cpu
)
584 struct ftrace_profile_stat
*stat
;
587 stat
= &per_cpu(ftrace_profile_stats
, cpu
);
590 /* If the profile is already created, simply reset it */
591 ftrace_profile_reset(stat
);
596 * We are profiling all functions, but usually only a few thousand
597 * functions are hit. We'll make a hash of 1024 items.
599 size
= FTRACE_PROFILE_HASH_SIZE
;
601 stat
->hash
= kzalloc(sizeof(struct hlist_head
) * size
, GFP_KERNEL
);
606 if (!ftrace_profile_bits
) {
609 for (; size
; size
>>= 1)
610 ftrace_profile_bits
++;
613 /* Preallocate the function profiling pages */
614 if (ftrace_profile_pages_init(stat
) < 0) {
623 static int ftrace_profile_init(void)
628 for_each_online_cpu(cpu
) {
629 ret
= ftrace_profile_init_cpu(cpu
);
637 /* interrupts must be disabled */
638 static struct ftrace_profile
*
639 ftrace_find_profiled_func(struct ftrace_profile_stat
*stat
, unsigned long ip
)
641 struct ftrace_profile
*rec
;
642 struct hlist_head
*hhd
;
643 struct hlist_node
*n
;
646 key
= hash_long(ip
, ftrace_profile_bits
);
647 hhd
= &stat
->hash
[key
];
649 if (hlist_empty(hhd
))
652 hlist_for_each_entry_rcu(rec
, n
, hhd
, node
) {
660 static void ftrace_add_profile(struct ftrace_profile_stat
*stat
,
661 struct ftrace_profile
*rec
)
665 key
= hash_long(rec
->ip
, ftrace_profile_bits
);
666 hlist_add_head_rcu(&rec
->node
, &stat
->hash
[key
]);
670 * The memory is already allocated, this simply finds a new record to use.
672 static struct ftrace_profile
*
673 ftrace_profile_alloc(struct ftrace_profile_stat
*stat
, unsigned long ip
)
675 struct ftrace_profile
*rec
= NULL
;
677 /* prevent recursion (from NMIs) */
678 if (atomic_inc_return(&stat
->disabled
) != 1)
682 * Try to find the function again since an NMI
683 * could have added it
685 rec
= ftrace_find_profiled_func(stat
, ip
);
689 if (stat
->pages
->index
== PROFILES_PER_PAGE
) {
690 if (!stat
->pages
->next
)
692 stat
->pages
= stat
->pages
->next
;
695 rec
= &stat
->pages
->records
[stat
->pages
->index
++];
697 ftrace_add_profile(stat
, rec
);
700 atomic_dec(&stat
->disabled
);
706 function_profile_call(unsigned long ip
, unsigned long parent_ip
)
708 struct ftrace_profile_stat
*stat
;
709 struct ftrace_profile
*rec
;
712 if (!ftrace_profile_enabled
)
715 local_irq_save(flags
);
717 stat
= &__get_cpu_var(ftrace_profile_stats
);
718 if (!stat
->hash
|| !ftrace_profile_enabled
)
721 rec
= ftrace_find_profiled_func(stat
, ip
);
723 rec
= ftrace_profile_alloc(stat
, ip
);
730 local_irq_restore(flags
);
733 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
734 static int profile_graph_entry(struct ftrace_graph_ent
*trace
)
736 function_profile_call(trace
->func
, 0);
740 static void profile_graph_return(struct ftrace_graph_ret
*trace
)
742 struct ftrace_profile_stat
*stat
;
743 unsigned long long calltime
;
744 struct ftrace_profile
*rec
;
747 local_irq_save(flags
);
748 stat
= &__get_cpu_var(ftrace_profile_stats
);
749 if (!stat
->hash
|| !ftrace_profile_enabled
)
752 /* If the calltime was zero'd ignore it */
753 if (!trace
->calltime
)
756 calltime
= trace
->rettime
- trace
->calltime
;
758 if (!(trace_flags
& TRACE_ITER_GRAPH_TIME
)) {
761 index
= trace
->depth
;
763 /* Append this call time to the parent time to subtract */
765 current
->ret_stack
[index
- 1].subtime
+= calltime
;
767 if (current
->ret_stack
[index
].subtime
< calltime
)
768 calltime
-= current
->ret_stack
[index
].subtime
;
773 rec
= ftrace_find_profiled_func(stat
, trace
->func
);
775 rec
->time
+= calltime
;
776 rec
->time_squared
+= calltime
* calltime
;
780 local_irq_restore(flags
);
783 static int register_ftrace_profiler(void)
785 return register_ftrace_graph(&profile_graph_return
,
786 &profile_graph_entry
);
789 static void unregister_ftrace_profiler(void)
791 unregister_ftrace_graph();
794 static struct ftrace_ops ftrace_profile_ops __read_mostly
= {
795 .func
= function_profile_call
,
798 static int register_ftrace_profiler(void)
800 return register_ftrace_function(&ftrace_profile_ops
);
803 static void unregister_ftrace_profiler(void)
805 unregister_ftrace_function(&ftrace_profile_ops
);
807 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
810 ftrace_profile_write(struct file
*filp
, const char __user
*ubuf
,
811 size_t cnt
, loff_t
*ppos
)
816 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
822 mutex_lock(&ftrace_profile_lock
);
823 if (ftrace_profile_enabled
^ val
) {
825 ret
= ftrace_profile_init();
831 ret
= register_ftrace_profiler();
836 ftrace_profile_enabled
= 1;
838 ftrace_profile_enabled
= 0;
840 * unregister_ftrace_profiler calls stop_machine
841 * so this acts like an synchronize_sched.
843 unregister_ftrace_profiler();
847 mutex_unlock(&ftrace_profile_lock
);
855 ftrace_profile_read(struct file
*filp
, char __user
*ubuf
,
856 size_t cnt
, loff_t
*ppos
)
858 char buf
[64]; /* big enough to hold a number */
861 r
= sprintf(buf
, "%u\n", ftrace_profile_enabled
);
862 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
865 static const struct file_operations ftrace_profile_fops
= {
866 .open
= tracing_open_generic
,
867 .read
= ftrace_profile_read
,
868 .write
= ftrace_profile_write
,
869 .llseek
= default_llseek
,
872 /* used to initialize the real stat files */
873 static struct tracer_stat function_stats __initdata
= {
875 .stat_start
= function_stat_start
,
876 .stat_next
= function_stat_next
,
877 .stat_cmp
= function_stat_cmp
,
878 .stat_headers
= function_stat_headers
,
879 .stat_show
= function_stat_show
882 static __init
void ftrace_profile_debugfs(struct dentry
*d_tracer
)
884 struct ftrace_profile_stat
*stat
;
885 struct dentry
*entry
;
890 for_each_possible_cpu(cpu
) {
891 stat
= &per_cpu(ftrace_profile_stats
, cpu
);
893 /* allocate enough for function name + cpu number */
894 name
= kmalloc(32, GFP_KERNEL
);
897 * The files created are permanent, if something happens
898 * we still do not free memory.
901 "Could not allocate stat file for cpu %d\n",
905 stat
->stat
= function_stats
;
906 snprintf(name
, 32, "function%d", cpu
);
907 stat
->stat
.name
= name
;
908 ret
= register_stat_tracer(&stat
->stat
);
911 "Could not register function stat for cpu %d\n",
918 entry
= debugfs_create_file("function_profile_enabled", 0644,
919 d_tracer
, NULL
, &ftrace_profile_fops
);
921 pr_warning("Could not create debugfs "
922 "'function_profile_enabled' entry\n");
925 #else /* CONFIG_FUNCTION_PROFILER */
926 static __init
void ftrace_profile_debugfs(struct dentry
*d_tracer
)
929 #endif /* CONFIG_FUNCTION_PROFILER */
931 static struct pid
* const ftrace_swapper_pid
= &init_struct_pid
;
933 #ifdef CONFIG_DYNAMIC_FTRACE
935 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
936 # error Dynamic ftrace depends on MCOUNT_RECORD
939 static struct hlist_head ftrace_func_hash
[FTRACE_FUNC_HASHSIZE
] __read_mostly
;
941 struct ftrace_func_probe
{
942 struct hlist_node node
;
943 struct ftrace_probe_ops
*ops
;
951 FTRACE_UPDATE_CALLS
= (1 << 0),
952 FTRACE_DISABLE_CALLS
= (1 << 1),
953 FTRACE_UPDATE_TRACE_FUNC
= (1 << 2),
954 FTRACE_START_FUNC_RET
= (1 << 3),
955 FTRACE_STOP_FUNC_RET
= (1 << 4),
957 struct ftrace_func_entry
{
958 struct hlist_node hlist
;
963 unsigned long size_bits
;
964 struct hlist_head
*buckets
;
970 * We make these constant because no one should touch them,
971 * but they are used as the default "empty hash", to avoid allocating
972 * it all the time. These are in a read only section such that if
973 * anyone does try to modify it, it will cause an exception.
975 static const struct hlist_head empty_buckets
[1];
976 static const struct ftrace_hash empty_hash
= {
977 .buckets
= (struct hlist_head
*)empty_buckets
,
979 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
981 static struct ftrace_ops global_ops
= {
983 .notrace_hash
= EMPTY_HASH
,
984 .filter_hash
= EMPTY_HASH
,
987 static struct dyn_ftrace
*ftrace_new_addrs
;
989 static DEFINE_MUTEX(ftrace_regex_lock
);
992 struct ftrace_page
*next
;
994 struct dyn_ftrace records
[];
997 #define ENTRIES_PER_PAGE \
998 ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
1000 /* estimate from running different kernels */
1001 #define NR_TO_INIT 10000
1003 static struct ftrace_page
*ftrace_pages_start
;
1004 static struct ftrace_page
*ftrace_pages
;
1006 static struct dyn_ftrace
*ftrace_free_records
;
1008 static struct ftrace_func_entry
*
1009 ftrace_lookup_ip(struct ftrace_hash
*hash
, unsigned long ip
)
1012 struct ftrace_func_entry
*entry
;
1013 struct hlist_head
*hhd
;
1014 struct hlist_node
*n
;
1019 if (hash
->size_bits
> 0)
1020 key
= hash_long(ip
, hash
->size_bits
);
1024 hhd
= &hash
->buckets
[key
];
1026 hlist_for_each_entry_rcu(entry
, n
, hhd
, hlist
) {
1027 if (entry
->ip
== ip
)
1033 static void __add_hash_entry(struct ftrace_hash
*hash
,
1034 struct ftrace_func_entry
*entry
)
1036 struct hlist_head
*hhd
;
1039 if (hash
->size_bits
)
1040 key
= hash_long(entry
->ip
, hash
->size_bits
);
1044 hhd
= &hash
->buckets
[key
];
1045 hlist_add_head(&entry
->hlist
, hhd
);
1049 static int add_hash_entry(struct ftrace_hash
*hash
, unsigned long ip
)
1051 struct ftrace_func_entry
*entry
;
1053 entry
= kmalloc(sizeof(*entry
), GFP_KERNEL
);
1058 __add_hash_entry(hash
, entry
);
1064 free_hash_entry(struct ftrace_hash
*hash
,
1065 struct ftrace_func_entry
*entry
)
1067 hlist_del(&entry
->hlist
);
1073 remove_hash_entry(struct ftrace_hash
*hash
,
1074 struct ftrace_func_entry
*entry
)
1076 hlist_del(&entry
->hlist
);
1080 static void ftrace_hash_clear(struct ftrace_hash
*hash
)
1082 struct hlist_head
*hhd
;
1083 struct hlist_node
*tp
, *tn
;
1084 struct ftrace_func_entry
*entry
;
1085 int size
= 1 << hash
->size_bits
;
1091 for (i
= 0; i
< size
; i
++) {
1092 hhd
= &hash
->buckets
[i
];
1093 hlist_for_each_entry_safe(entry
, tp
, tn
, hhd
, hlist
)
1094 free_hash_entry(hash
, entry
);
1096 FTRACE_WARN_ON(hash
->count
);
1099 static void free_ftrace_hash(struct ftrace_hash
*hash
)
1101 if (!hash
|| hash
== EMPTY_HASH
)
1103 ftrace_hash_clear(hash
);
1104 kfree(hash
->buckets
);
1108 static void __free_ftrace_hash_rcu(struct rcu_head
*rcu
)
1110 struct ftrace_hash
*hash
;
1112 hash
= container_of(rcu
, struct ftrace_hash
, rcu
);
1113 free_ftrace_hash(hash
);
1116 static void free_ftrace_hash_rcu(struct ftrace_hash
*hash
)
1118 if (!hash
|| hash
== EMPTY_HASH
)
1120 call_rcu_sched(&hash
->rcu
, __free_ftrace_hash_rcu
);
1123 static struct ftrace_hash
*alloc_ftrace_hash(int size_bits
)
1125 struct ftrace_hash
*hash
;
1128 hash
= kzalloc(sizeof(*hash
), GFP_KERNEL
);
1132 size
= 1 << size_bits
;
1133 hash
->buckets
= kzalloc(sizeof(*hash
->buckets
) * size
, GFP_KERNEL
);
1135 if (!hash
->buckets
) {
1140 hash
->size_bits
= size_bits
;
1145 static struct ftrace_hash
*
1146 alloc_and_copy_ftrace_hash(int size_bits
, struct ftrace_hash
*hash
)
1148 struct ftrace_func_entry
*entry
;
1149 struct ftrace_hash
*new_hash
;
1150 struct hlist_node
*tp
;
1155 new_hash
= alloc_ftrace_hash(size_bits
);
1160 if (!hash
|| !hash
->count
)
1163 size
= 1 << hash
->size_bits
;
1164 for (i
= 0; i
< size
; i
++) {
1165 hlist_for_each_entry(entry
, tp
, &hash
->buckets
[i
], hlist
) {
1166 ret
= add_hash_entry(new_hash
, entry
->ip
);
1172 FTRACE_WARN_ON(new_hash
->count
!= hash
->count
);
1177 free_ftrace_hash(new_hash
);
1182 ftrace_hash_rec_disable(struct ftrace_ops
*ops
, int filter_hash
);
1184 ftrace_hash_rec_enable(struct ftrace_ops
*ops
, int filter_hash
);
1187 ftrace_hash_move(struct ftrace_ops
*ops
, int enable
,
1188 struct ftrace_hash
**dst
, struct ftrace_hash
*src
)
1190 struct ftrace_func_entry
*entry
;
1191 struct hlist_node
*tp
, *tn
;
1192 struct hlist_head
*hhd
;
1193 struct ftrace_hash
*old_hash
;
1194 struct ftrace_hash
*new_hash
;
1196 int size
= src
->count
;
1202 * Remove the current set, update the hash and add
1205 ftrace_hash_rec_disable(ops
, enable
);
1208 * If the new source is empty, just free dst and assign it
1212 free_ftrace_hash_rcu(*dst
);
1213 rcu_assign_pointer(*dst
, EMPTY_HASH
);
1214 /* still need to update the function records */
1220 * Make the hash size about 1/2 the # found
1222 for (size
/= 2; size
; size
>>= 1)
1225 /* Don't allocate too much */
1226 if (bits
> FTRACE_HASH_MAX_BITS
)
1227 bits
= FTRACE_HASH_MAX_BITS
;
1230 new_hash
= alloc_ftrace_hash(bits
);
1234 size
= 1 << src
->size_bits
;
1235 for (i
= 0; i
< size
; i
++) {
1236 hhd
= &src
->buckets
[i
];
1237 hlist_for_each_entry_safe(entry
, tp
, tn
, hhd
, hlist
) {
1239 key
= hash_long(entry
->ip
, bits
);
1242 remove_hash_entry(src
, entry
);
1243 __add_hash_entry(new_hash
, entry
);
1248 rcu_assign_pointer(*dst
, new_hash
);
1249 free_ftrace_hash_rcu(old_hash
);
1254 * Enable regardless of ret:
1255 * On success, we enable the new hash.
1256 * On failure, we re-enable the original hash.
1258 ftrace_hash_rec_enable(ops
, enable
);
1264 * Test the hashes for this ops to see if we want to call
1265 * the ops->func or not.
1267 * It's a match if the ip is in the ops->filter_hash or
1268 * the filter_hash does not exist or is empty,
1270 * the ip is not in the ops->notrace_hash.
1272 * This needs to be called with preemption disabled as
1273 * the hashes are freed with call_rcu_sched().
1276 ftrace_ops_test(struct ftrace_ops
*ops
, unsigned long ip
)
1278 struct ftrace_hash
*filter_hash
;
1279 struct ftrace_hash
*notrace_hash
;
1282 filter_hash
= rcu_dereference_raw(ops
->filter_hash
);
1283 notrace_hash
= rcu_dereference_raw(ops
->notrace_hash
);
1285 if ((!filter_hash
|| !filter_hash
->count
||
1286 ftrace_lookup_ip(filter_hash
, ip
)) &&
1287 (!notrace_hash
|| !notrace_hash
->count
||
1288 !ftrace_lookup_ip(notrace_hash
, ip
)))
1297 * This is a double for. Do not use 'break' to break out of the loop,
1298 * you must use a goto.
1300 #define do_for_each_ftrace_rec(pg, rec) \
1301 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1303 for (_____i = 0; _____i < pg->index; _____i++) { \
1304 rec = &pg->records[_____i];
1306 #define while_for_each_ftrace_rec() \
1310 static void __ftrace_hash_rec_update(struct ftrace_ops
*ops
,
1314 struct ftrace_hash
*hash
;
1315 struct ftrace_hash
*other_hash
;
1316 struct ftrace_page
*pg
;
1317 struct dyn_ftrace
*rec
;
1321 /* Only update if the ops has been registered */
1322 if (!(ops
->flags
& FTRACE_OPS_FL_ENABLED
))
1326 * In the filter_hash case:
1327 * If the count is zero, we update all records.
1328 * Otherwise we just update the items in the hash.
1330 * In the notrace_hash case:
1331 * We enable the update in the hash.
1332 * As disabling notrace means enabling the tracing,
1333 * and enabling notrace means disabling, the inc variable
1337 hash
= ops
->filter_hash
;
1338 other_hash
= ops
->notrace_hash
;
1339 if (!hash
|| !hash
->count
)
1343 hash
= ops
->notrace_hash
;
1344 other_hash
= ops
->filter_hash
;
1346 * If the notrace hash has no items,
1347 * then there's nothing to do.
1349 if (hash
&& !hash
->count
)
1353 do_for_each_ftrace_rec(pg
, rec
) {
1354 int in_other_hash
= 0;
1360 * Only the filter_hash affects all records.
1361 * Update if the record is not in the notrace hash.
1363 if (!other_hash
|| !ftrace_lookup_ip(other_hash
, rec
->ip
))
1366 in_hash
= hash
&& !!ftrace_lookup_ip(hash
, rec
->ip
);
1367 in_other_hash
= other_hash
&& !!ftrace_lookup_ip(other_hash
, rec
->ip
);
1372 if (filter_hash
&& in_hash
&& !in_other_hash
)
1374 else if (!filter_hash
&& in_hash
&&
1375 (in_other_hash
|| !other_hash
->count
))
1383 if (FTRACE_WARN_ON((rec
->flags
& ~FTRACE_FL_MASK
) == FTRACE_REF_MAX
))
1386 if (FTRACE_WARN_ON((rec
->flags
& ~FTRACE_FL_MASK
) == 0))
1391 /* Shortcut, if we handled all records, we are done. */
1392 if (!all
&& count
== hash
->count
)
1394 } while_for_each_ftrace_rec();
1397 static void ftrace_hash_rec_disable(struct ftrace_ops
*ops
,
1400 __ftrace_hash_rec_update(ops
, filter_hash
, 0);
1403 static void ftrace_hash_rec_enable(struct ftrace_ops
*ops
,
1406 __ftrace_hash_rec_update(ops
, filter_hash
, 1);
1409 static void ftrace_free_rec(struct dyn_ftrace
*rec
)
1411 rec
->freelist
= ftrace_free_records
;
1412 ftrace_free_records
= rec
;
1413 rec
->flags
|= FTRACE_FL_FREE
;
1416 static struct dyn_ftrace
*ftrace_alloc_dyn_node(unsigned long ip
)
1418 struct dyn_ftrace
*rec
;
1420 /* First check for freed records */
1421 if (ftrace_free_records
) {
1422 rec
= ftrace_free_records
;
1424 if (unlikely(!(rec
->flags
& FTRACE_FL_FREE
))) {
1425 FTRACE_WARN_ON_ONCE(1);
1426 ftrace_free_records
= NULL
;
1430 ftrace_free_records
= rec
->freelist
;
1431 memset(rec
, 0, sizeof(*rec
));
1435 if (ftrace_pages
->index
== ENTRIES_PER_PAGE
) {
1436 if (!ftrace_pages
->next
) {
1437 /* allocate another page */
1438 ftrace_pages
->next
=
1439 (void *)get_zeroed_page(GFP_KERNEL
);
1440 if (!ftrace_pages
->next
)
1443 ftrace_pages
= ftrace_pages
->next
;
1446 return &ftrace_pages
->records
[ftrace_pages
->index
++];
1449 static struct dyn_ftrace
*
1450 ftrace_record_ip(unsigned long ip
)
1452 struct dyn_ftrace
*rec
;
1454 if (ftrace_disabled
)
1457 rec
= ftrace_alloc_dyn_node(ip
);
1462 rec
->newlist
= ftrace_new_addrs
;
1463 ftrace_new_addrs
= rec
;
1468 static void print_ip_ins(const char *fmt
, unsigned char *p
)
1472 printk(KERN_CONT
"%s", fmt
);
1474 for (i
= 0; i
< MCOUNT_INSN_SIZE
; i
++)
1475 printk(KERN_CONT
"%s%02x", i
? ":" : "", p
[i
]);
1478 static void ftrace_bug(int failed
, unsigned long ip
)
1482 FTRACE_WARN_ON_ONCE(1);
1483 pr_info("ftrace faulted on modifying ");
1487 FTRACE_WARN_ON_ONCE(1);
1488 pr_info("ftrace failed to modify ");
1490 print_ip_ins(" actual: ", (unsigned char *)ip
);
1491 printk(KERN_CONT
"\n");
1494 FTRACE_WARN_ON_ONCE(1);
1495 pr_info("ftrace faulted on writing ");
1499 FTRACE_WARN_ON_ONCE(1);
1500 pr_info("ftrace faulted on unknown error ");
1506 /* Return 1 if the address range is reserved for ftrace */
1507 int ftrace_text_reserved(void *start
, void *end
)
1509 struct dyn_ftrace
*rec
;
1510 struct ftrace_page
*pg
;
1512 do_for_each_ftrace_rec(pg
, rec
) {
1513 if (rec
->ip
<= (unsigned long)end
&&
1514 rec
->ip
+ MCOUNT_INSN_SIZE
> (unsigned long)start
)
1516 } while_for_each_ftrace_rec();
1522 __ftrace_replace_code(struct dyn_ftrace
*rec
, int update
)
1524 unsigned long ftrace_addr
;
1525 unsigned long flag
= 0UL;
1527 ftrace_addr
= (unsigned long)FTRACE_ADDR
;
1530 * If we are updating calls:
1532 * If the record has a ref count, then we need to enable it
1533 * because someone is using it.
1535 * Otherwise we make sure its disabled.
1537 * If we are disabling calls, then disable all records that
1540 if (update
&& (rec
->flags
& ~FTRACE_FL_MASK
))
1541 flag
= FTRACE_FL_ENABLED
;
1543 /* If the state of this record hasn't changed, then do nothing */
1544 if ((rec
->flags
& FTRACE_FL_ENABLED
) == flag
)
1548 rec
->flags
|= FTRACE_FL_ENABLED
;
1549 return ftrace_make_call(rec
, ftrace_addr
);
1552 rec
->flags
&= ~FTRACE_FL_ENABLED
;
1553 return ftrace_make_nop(NULL
, rec
, ftrace_addr
);
1556 static void ftrace_replace_code(int update
)
1558 struct dyn_ftrace
*rec
;
1559 struct ftrace_page
*pg
;
1562 if (unlikely(ftrace_disabled
))
1565 do_for_each_ftrace_rec(pg
, rec
) {
1566 /* Skip over free records */
1567 if (rec
->flags
& FTRACE_FL_FREE
)
1570 failed
= __ftrace_replace_code(rec
, update
);
1572 ftrace_bug(failed
, rec
->ip
);
1573 /* Stop processing */
1576 } while_for_each_ftrace_rec();
1580 ftrace_code_disable(struct module
*mod
, struct dyn_ftrace
*rec
)
1587 if (unlikely(ftrace_disabled
))
1590 ret
= ftrace_make_nop(mod
, rec
, MCOUNT_ADDR
);
1592 ftrace_bug(ret
, ip
);
1599 * archs can override this function if they must do something
1600 * before the modifying code is performed.
1602 int __weak
ftrace_arch_code_modify_prepare(void)
1608 * archs can override this function if they must do something
1609 * after the modifying code is performed.
1611 int __weak
ftrace_arch_code_modify_post_process(void)
1616 static int __ftrace_modify_code(void *data
)
1618 int *command
= data
;
1621 * Do not call function tracer while we update the code.
1622 * We are in stop machine, no worrying about races.
1624 function_trace_stop
++;
1626 if (*command
& FTRACE_UPDATE_CALLS
)
1627 ftrace_replace_code(1);
1628 else if (*command
& FTRACE_DISABLE_CALLS
)
1629 ftrace_replace_code(0);
1631 if (*command
& FTRACE_UPDATE_TRACE_FUNC
)
1632 ftrace_update_ftrace_func(ftrace_trace_function
);
1634 if (*command
& FTRACE_START_FUNC_RET
)
1635 ftrace_enable_ftrace_graph_caller();
1636 else if (*command
& FTRACE_STOP_FUNC_RET
)
1637 ftrace_disable_ftrace_graph_caller();
1639 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
1641 * For archs that call ftrace_test_stop_func(), we must
1642 * wait till after we update all the function callers
1643 * before we update the callback. This keeps different
1644 * ops that record different functions from corrupting
1647 __ftrace_trace_function
= __ftrace_trace_function_delay
;
1649 function_trace_stop
--;
1654 static void ftrace_run_update_code(int command
)
1658 ret
= ftrace_arch_code_modify_prepare();
1659 FTRACE_WARN_ON(ret
);
1663 stop_machine(__ftrace_modify_code
, &command
, NULL
);
1665 ret
= ftrace_arch_code_modify_post_process();
1666 FTRACE_WARN_ON(ret
);
1669 static ftrace_func_t saved_ftrace_func
;
1670 static int ftrace_start_up
;
1671 static int global_start_up
;
1673 static void ftrace_startup_enable(int command
)
1675 if (saved_ftrace_func
!= ftrace_trace_function
) {
1676 saved_ftrace_func
= ftrace_trace_function
;
1677 command
|= FTRACE_UPDATE_TRACE_FUNC
;
1680 if (!command
|| !ftrace_enabled
)
1683 ftrace_run_update_code(command
);
1686 static int ftrace_startup(struct ftrace_ops
*ops
, int command
)
1688 bool hash_enable
= true;
1690 if (unlikely(ftrace_disabled
))
1694 command
|= FTRACE_UPDATE_CALLS
;
1696 /* ops marked global share the filter hashes */
1697 if (ops
->flags
& FTRACE_OPS_FL_GLOBAL
) {
1699 /* Don't update hash if global is already set */
1700 if (global_start_up
)
1701 hash_enable
= false;
1705 ops
->flags
|= FTRACE_OPS_FL_ENABLED
;
1707 ftrace_hash_rec_enable(ops
, 1);
1709 ftrace_startup_enable(command
);
1714 static void ftrace_shutdown(struct ftrace_ops
*ops
, int command
)
1716 bool hash_disable
= true;
1718 if (unlikely(ftrace_disabled
))
1723 * Just warn in case of unbalance, no need to kill ftrace, it's not
1724 * critical but the ftrace_call callers may be never nopped again after
1725 * further ftrace uses.
1727 WARN_ON_ONCE(ftrace_start_up
< 0);
1729 if (ops
->flags
& FTRACE_OPS_FL_GLOBAL
) {
1732 WARN_ON_ONCE(global_start_up
< 0);
1733 /* Don't update hash if global still has users */
1734 if (global_start_up
) {
1735 WARN_ON_ONCE(!ftrace_start_up
);
1736 hash_disable
= false;
1741 ftrace_hash_rec_disable(ops
, 1);
1743 if (ops
!= &global_ops
|| !global_start_up
)
1744 ops
->flags
&= ~FTRACE_OPS_FL_ENABLED
;
1746 command
|= FTRACE_UPDATE_CALLS
;
1748 if (saved_ftrace_func
!= ftrace_trace_function
) {
1749 saved_ftrace_func
= ftrace_trace_function
;
1750 command
|= FTRACE_UPDATE_TRACE_FUNC
;
1753 if (!command
|| !ftrace_enabled
)
1756 ftrace_run_update_code(command
);
1759 static void ftrace_startup_sysctl(void)
1761 if (unlikely(ftrace_disabled
))
1764 /* Force update next time */
1765 saved_ftrace_func
= NULL
;
1766 /* ftrace_start_up is true if we want ftrace running */
1767 if (ftrace_start_up
)
1768 ftrace_run_update_code(FTRACE_UPDATE_CALLS
);
1771 static void ftrace_shutdown_sysctl(void)
1773 if (unlikely(ftrace_disabled
))
1776 /* ftrace_start_up is true if ftrace is running */
1777 if (ftrace_start_up
)
1778 ftrace_run_update_code(FTRACE_DISABLE_CALLS
);
1781 static cycle_t ftrace_update_time
;
1782 static unsigned long ftrace_update_cnt
;
1783 unsigned long ftrace_update_tot_cnt
;
1785 static int ops_traces_mod(struct ftrace_ops
*ops
)
1787 struct ftrace_hash
*hash
;
1789 hash
= ops
->filter_hash
;
1790 return !!(!hash
|| !hash
->count
);
1793 static int ftrace_update_code(struct module
*mod
)
1795 struct dyn_ftrace
*p
;
1796 cycle_t start
, stop
;
1797 unsigned long ref
= 0;
1800 * When adding a module, we need to check if tracers are
1801 * currently enabled and if they are set to trace all functions.
1802 * If they are, we need to enable the module functions as well
1803 * as update the reference counts for those function records.
1806 struct ftrace_ops
*ops
;
1808 for (ops
= ftrace_ops_list
;
1809 ops
!= &ftrace_list_end
; ops
= ops
->next
) {
1810 if (ops
->flags
& FTRACE_OPS_FL_ENABLED
&&
1811 ops_traces_mod(ops
))
1816 start
= ftrace_now(raw_smp_processor_id());
1817 ftrace_update_cnt
= 0;
1819 while (ftrace_new_addrs
) {
1821 /* If something went wrong, bail without enabling anything */
1822 if (unlikely(ftrace_disabled
))
1825 p
= ftrace_new_addrs
;
1826 ftrace_new_addrs
= p
->newlist
;
1830 * Do the initial record conversion from mcount jump
1831 * to the NOP instructions.
1833 if (!ftrace_code_disable(mod
, p
)) {
1839 ftrace_update_cnt
++;
1842 * If the tracing is enabled, go ahead and enable the record.
1844 * The reason not to enable the record immediatelly is the
1845 * inherent check of ftrace_make_nop/ftrace_make_call for
1846 * correct previous instructions. Making first the NOP
1847 * conversion puts the module to the correct state, thus
1848 * passing the ftrace_make_call check.
1850 if (ftrace_start_up
&& ref
) {
1851 int failed
= __ftrace_replace_code(p
, 1);
1853 ftrace_bug(failed
, p
->ip
);
1859 stop
= ftrace_now(raw_smp_processor_id());
1860 ftrace_update_time
= stop
- start
;
1861 ftrace_update_tot_cnt
+= ftrace_update_cnt
;
1866 static int __init
ftrace_dyn_table_alloc(unsigned long num_to_init
)
1868 struct ftrace_page
*pg
;
1872 /* allocate a few pages */
1873 ftrace_pages_start
= (void *)get_zeroed_page(GFP_KERNEL
);
1874 if (!ftrace_pages_start
)
1878 * Allocate a few more pages.
1880 * TODO: have some parser search vmlinux before
1881 * final linking to find all calls to ftrace.
1883 * a) know how many pages to allocate.
1885 * b) set up the table then.
1887 * The dynamic code is still necessary for
1891 pg
= ftrace_pages
= ftrace_pages_start
;
1893 cnt
= num_to_init
/ ENTRIES_PER_PAGE
;
1894 pr_info("ftrace: allocating %ld entries in %d pages\n",
1895 num_to_init
, cnt
+ 1);
1897 for (i
= 0; i
< cnt
; i
++) {
1898 pg
->next
= (void *)get_zeroed_page(GFP_KERNEL
);
1900 /* If we fail, we'll try later anyway */
1911 FTRACE_ITER_FILTER
= (1 << 0),
1912 FTRACE_ITER_NOTRACE
= (1 << 1),
1913 FTRACE_ITER_PRINTALL
= (1 << 2),
1914 FTRACE_ITER_HASH
= (1 << 3),
1915 FTRACE_ITER_ENABLED
= (1 << 4),
1918 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
1920 struct ftrace_iterator
{
1923 struct ftrace_page
*pg
;
1924 struct dyn_ftrace
*func
;
1925 struct ftrace_func_probe
*probe
;
1926 struct trace_parser parser
;
1927 struct ftrace_hash
*hash
;
1928 struct ftrace_ops
*ops
;
1935 t_hash_next(struct seq_file
*m
, loff_t
*pos
)
1937 struct ftrace_iterator
*iter
= m
->private;
1938 struct hlist_node
*hnd
= NULL
;
1939 struct hlist_head
*hhd
;
1945 hnd
= &iter
->probe
->node
;
1947 if (iter
->hidx
>= FTRACE_FUNC_HASHSIZE
)
1950 hhd
= &ftrace_func_hash
[iter
->hidx
];
1952 if (hlist_empty(hhd
)) {
1968 if (WARN_ON_ONCE(!hnd
))
1971 iter
->probe
= hlist_entry(hnd
, struct ftrace_func_probe
, node
);
1976 static void *t_hash_start(struct seq_file
*m
, loff_t
*pos
)
1978 struct ftrace_iterator
*iter
= m
->private;
1982 if (iter
->func_pos
> *pos
)
1986 for (l
= 0; l
<= (*pos
- iter
->func_pos
); ) {
1987 p
= t_hash_next(m
, &l
);
1994 /* Only set this if we have an item */
1995 iter
->flags
|= FTRACE_ITER_HASH
;
2001 t_hash_show(struct seq_file
*m
, struct ftrace_iterator
*iter
)
2003 struct ftrace_func_probe
*rec
;
2006 if (WARN_ON_ONCE(!rec
))
2009 if (rec
->ops
->print
)
2010 return rec
->ops
->print(m
, rec
->ip
, rec
->ops
, rec
->data
);
2012 seq_printf(m
, "%ps:%ps", (void *)rec
->ip
, (void *)rec
->ops
->func
);
2015 seq_printf(m
, ":%p", rec
->data
);
2022 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
2024 struct ftrace_iterator
*iter
= m
->private;
2025 struct ftrace_ops
*ops
= &global_ops
;
2026 struct dyn_ftrace
*rec
= NULL
;
2028 if (unlikely(ftrace_disabled
))
2031 if (iter
->flags
& FTRACE_ITER_HASH
)
2032 return t_hash_next(m
, pos
);
2035 iter
->pos
= iter
->func_pos
= *pos
;
2037 if (iter
->flags
& FTRACE_ITER_PRINTALL
)
2038 return t_hash_start(m
, pos
);
2041 if (iter
->idx
>= iter
->pg
->index
) {
2042 if (iter
->pg
->next
) {
2043 iter
->pg
= iter
->pg
->next
;
2048 rec
= &iter
->pg
->records
[iter
->idx
++];
2049 if ((rec
->flags
& FTRACE_FL_FREE
) ||
2051 ((iter
->flags
& FTRACE_ITER_FILTER
) &&
2052 !(ftrace_lookup_ip(ops
->filter_hash
, rec
->ip
))) ||
2054 ((iter
->flags
& FTRACE_ITER_NOTRACE
) &&
2055 !ftrace_lookup_ip(ops
->notrace_hash
, rec
->ip
)) ||
2057 ((iter
->flags
& FTRACE_ITER_ENABLED
) &&
2058 !(rec
->flags
& ~FTRACE_FL_MASK
))) {
2066 return t_hash_start(m
, pos
);
2073 static void reset_iter_read(struct ftrace_iterator
*iter
)
2077 iter
->flags
&= ~(FTRACE_ITER_PRINTALL
& FTRACE_ITER_HASH
);
2080 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
2082 struct ftrace_iterator
*iter
= m
->private;
2083 struct ftrace_ops
*ops
= &global_ops
;
2087 mutex_lock(&ftrace_lock
);
2089 if (unlikely(ftrace_disabled
))
2093 * If an lseek was done, then reset and start from beginning.
2095 if (*pos
< iter
->pos
)
2096 reset_iter_read(iter
);
2099 * For set_ftrace_filter reading, if we have the filter
2100 * off, we can short cut and just print out that all
2101 * functions are enabled.
2103 if (iter
->flags
& FTRACE_ITER_FILTER
&& !ops
->filter_hash
->count
) {
2105 return t_hash_start(m
, pos
);
2106 iter
->flags
|= FTRACE_ITER_PRINTALL
;
2107 /* reset in case of seek/pread */
2108 iter
->flags
&= ~FTRACE_ITER_HASH
;
2112 if (iter
->flags
& FTRACE_ITER_HASH
)
2113 return t_hash_start(m
, pos
);
2116 * Unfortunately, we need to restart at ftrace_pages_start
2117 * every time we let go of the ftrace_mutex. This is because
2118 * those pointers can change without the lock.
2120 iter
->pg
= ftrace_pages_start
;
2122 for (l
= 0; l
<= *pos
; ) {
2123 p
= t_next(m
, p
, &l
);
2129 if (iter
->flags
& FTRACE_ITER_FILTER
)
2130 return t_hash_start(m
, pos
);
2138 static void t_stop(struct seq_file
*m
, void *p
)
2140 mutex_unlock(&ftrace_lock
);
2143 static int t_show(struct seq_file
*m
, void *v
)
2145 struct ftrace_iterator
*iter
= m
->private;
2146 struct dyn_ftrace
*rec
;
2148 if (iter
->flags
& FTRACE_ITER_HASH
)
2149 return t_hash_show(m
, iter
);
2151 if (iter
->flags
& FTRACE_ITER_PRINTALL
) {
2152 seq_printf(m
, "#### all functions enabled ####\n");
2161 seq_printf(m
, "%ps", (void *)rec
->ip
);
2162 if (iter
->flags
& FTRACE_ITER_ENABLED
)
2163 seq_printf(m
, " (%ld)",
2164 rec
->flags
& ~FTRACE_FL_MASK
);
2165 seq_printf(m
, "\n");
2170 static const struct seq_operations show_ftrace_seq_ops
= {
2178 ftrace_avail_open(struct inode
*inode
, struct file
*file
)
2180 struct ftrace_iterator
*iter
;
2183 if (unlikely(ftrace_disabled
))
2186 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2190 iter
->pg
= ftrace_pages_start
;
2192 ret
= seq_open(file
, &show_ftrace_seq_ops
);
2194 struct seq_file
*m
= file
->private_data
;
2205 ftrace_enabled_open(struct inode
*inode
, struct file
*file
)
2207 struct ftrace_iterator
*iter
;
2210 if (unlikely(ftrace_disabled
))
2213 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2217 iter
->pg
= ftrace_pages_start
;
2218 iter
->flags
= FTRACE_ITER_ENABLED
;
2220 ret
= seq_open(file
, &show_ftrace_seq_ops
);
2222 struct seq_file
*m
= file
->private_data
;
2232 static void ftrace_filter_reset(struct ftrace_hash
*hash
)
2234 mutex_lock(&ftrace_lock
);
2235 ftrace_hash_clear(hash
);
2236 mutex_unlock(&ftrace_lock
);
2240 ftrace_regex_open(struct ftrace_ops
*ops
, int flag
,
2241 struct inode
*inode
, struct file
*file
)
2243 struct ftrace_iterator
*iter
;
2244 struct ftrace_hash
*hash
;
2247 if (unlikely(ftrace_disabled
))
2250 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2254 if (trace_parser_get_init(&iter
->parser
, FTRACE_BUFF_MAX
)) {
2259 if (flag
& FTRACE_ITER_NOTRACE
)
2260 hash
= ops
->notrace_hash
;
2262 hash
= ops
->filter_hash
;
2267 if (file
->f_mode
& FMODE_WRITE
) {
2268 mutex_lock(&ftrace_lock
);
2269 iter
->hash
= alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
, hash
);
2270 mutex_unlock(&ftrace_lock
);
2273 trace_parser_put(&iter
->parser
);
2279 mutex_lock(&ftrace_regex_lock
);
2281 if ((file
->f_mode
& FMODE_WRITE
) &&
2282 (file
->f_flags
& O_TRUNC
))
2283 ftrace_filter_reset(iter
->hash
);
2285 if (file
->f_mode
& FMODE_READ
) {
2286 iter
->pg
= ftrace_pages_start
;
2288 ret
= seq_open(file
, &show_ftrace_seq_ops
);
2290 struct seq_file
*m
= file
->private_data
;
2294 free_ftrace_hash(iter
->hash
);
2295 trace_parser_put(&iter
->parser
);
2299 file
->private_data
= iter
;
2300 mutex_unlock(&ftrace_regex_lock
);
2306 ftrace_filter_open(struct inode
*inode
, struct file
*file
)
2308 return ftrace_regex_open(&global_ops
, FTRACE_ITER_FILTER
,
2313 ftrace_notrace_open(struct inode
*inode
, struct file
*file
)
2315 return ftrace_regex_open(&global_ops
, FTRACE_ITER_NOTRACE
,
2320 ftrace_regex_lseek(struct file
*file
, loff_t offset
, int origin
)
2324 if (file
->f_mode
& FMODE_READ
)
2325 ret
= seq_lseek(file
, offset
, origin
);
2327 file
->f_pos
= ret
= 1;
2332 static int ftrace_match(char *str
, char *regex
, int len
, int type
)
2339 if (strcmp(str
, regex
) == 0)
2342 case MATCH_FRONT_ONLY
:
2343 if (strncmp(str
, regex
, len
) == 0)
2346 case MATCH_MIDDLE_ONLY
:
2347 if (strstr(str
, regex
))
2350 case MATCH_END_ONLY
:
2352 if (slen
>= len
&& memcmp(str
+ slen
- len
, regex
, len
) == 0)
2361 enter_record(struct ftrace_hash
*hash
, struct dyn_ftrace
*rec
, int not)
2363 struct ftrace_func_entry
*entry
;
2366 entry
= ftrace_lookup_ip(hash
, rec
->ip
);
2368 /* Do nothing if it doesn't exist */
2372 free_hash_entry(hash
, entry
);
2374 /* Do nothing if it exists */
2378 ret
= add_hash_entry(hash
, rec
->ip
);
2384 ftrace_match_record(struct dyn_ftrace
*rec
, char *mod
,
2385 char *regex
, int len
, int type
)
2387 char str
[KSYM_SYMBOL_LEN
];
2390 kallsyms_lookup(rec
->ip
, NULL
, NULL
, &modname
, str
);
2393 /* module lookup requires matching the module */
2394 if (!modname
|| strcmp(modname
, mod
))
2397 /* blank search means to match all funcs in the mod */
2402 return ftrace_match(str
, regex
, len
, type
);
2406 match_records(struct ftrace_hash
*hash
, char *buff
,
2407 int len
, char *mod
, int not)
2409 unsigned search_len
= 0;
2410 struct ftrace_page
*pg
;
2411 struct dyn_ftrace
*rec
;
2412 int type
= MATCH_FULL
;
2413 char *search
= buff
;
2418 type
= filter_parse_regex(buff
, len
, &search
, ¬);
2419 search_len
= strlen(search
);
2422 mutex_lock(&ftrace_lock
);
2424 if (unlikely(ftrace_disabled
))
2427 do_for_each_ftrace_rec(pg
, rec
) {
2429 if (ftrace_match_record(rec
, mod
, search
, search_len
, type
)) {
2430 ret
= enter_record(hash
, rec
, not);
2437 } while_for_each_ftrace_rec();
2439 mutex_unlock(&ftrace_lock
);
2445 ftrace_match_records(struct ftrace_hash
*hash
, char *buff
, int len
)
2447 return match_records(hash
, buff
, len
, NULL
, 0);
2451 ftrace_match_module_records(struct ftrace_hash
*hash
, char *buff
, char *mod
)
2455 /* blank or '*' mean the same */
2456 if (strcmp(buff
, "*") == 0)
2459 /* handle the case of 'dont filter this module' */
2460 if (strcmp(buff
, "!") == 0 || strcmp(buff
, "!*") == 0) {
2465 return match_records(hash
, buff
, strlen(buff
), mod
, not);
2469 * We register the module command as a template to show others how
2470 * to register the a command as well.
2474 ftrace_mod_callback(struct ftrace_hash
*hash
,
2475 char *func
, char *cmd
, char *param
, int enable
)
2481 * cmd == 'mod' because we only registered this func
2482 * for the 'mod' ftrace_func_command.
2483 * But if you register one func with multiple commands,
2484 * you can tell which command was used by the cmd
2488 /* we must have a module name */
2492 mod
= strsep(¶m
, ":");
2496 ret
= ftrace_match_module_records(hash
, func
, mod
);
2505 static struct ftrace_func_command ftrace_mod_cmd
= {
2507 .func
= ftrace_mod_callback
,
2510 static int __init
ftrace_mod_cmd_init(void)
2512 return register_ftrace_command(&ftrace_mod_cmd
);
2514 device_initcall(ftrace_mod_cmd_init
);
2517 function_trace_probe_call(unsigned long ip
, unsigned long parent_ip
)
2519 struct ftrace_func_probe
*entry
;
2520 struct hlist_head
*hhd
;
2521 struct hlist_node
*n
;
2524 key
= hash_long(ip
, FTRACE_HASH_BITS
);
2526 hhd
= &ftrace_func_hash
[key
];
2528 if (hlist_empty(hhd
))
2532 * Disable preemption for these calls to prevent a RCU grace
2533 * period. This syncs the hash iteration and freeing of items
2534 * on the hash. rcu_read_lock is too dangerous here.
2536 preempt_disable_notrace();
2537 hlist_for_each_entry_rcu(entry
, n
, hhd
, node
) {
2538 if (entry
->ip
== ip
)
2539 entry
->ops
->func(ip
, parent_ip
, &entry
->data
);
2541 preempt_enable_notrace();
2544 static struct ftrace_ops trace_probe_ops __read_mostly
=
2546 .func
= function_trace_probe_call
,
2549 static int ftrace_probe_registered
;
2551 static void __enable_ftrace_function_probe(void)
2556 if (ftrace_probe_registered
)
2559 for (i
= 0; i
< FTRACE_FUNC_HASHSIZE
; i
++) {
2560 struct hlist_head
*hhd
= &ftrace_func_hash
[i
];
2564 /* Nothing registered? */
2565 if (i
== FTRACE_FUNC_HASHSIZE
)
2568 ret
= __register_ftrace_function(&trace_probe_ops
);
2570 ret
= ftrace_startup(&trace_probe_ops
, 0);
2572 ftrace_probe_registered
= 1;
2575 static void __disable_ftrace_function_probe(void)
2580 if (!ftrace_probe_registered
)
2583 for (i
= 0; i
< FTRACE_FUNC_HASHSIZE
; i
++) {
2584 struct hlist_head
*hhd
= &ftrace_func_hash
[i
];
2589 /* no more funcs left */
2590 ret
= __unregister_ftrace_function(&trace_probe_ops
);
2592 ftrace_shutdown(&trace_probe_ops
, 0);
2594 ftrace_probe_registered
= 0;
2598 static void ftrace_free_entry_rcu(struct rcu_head
*rhp
)
2600 struct ftrace_func_probe
*entry
=
2601 container_of(rhp
, struct ftrace_func_probe
, rcu
);
2603 if (entry
->ops
->free
)
2604 entry
->ops
->free(&entry
->data
);
2610 register_ftrace_function_probe(char *glob
, struct ftrace_probe_ops
*ops
,
2613 struct ftrace_func_probe
*entry
;
2614 struct ftrace_page
*pg
;
2615 struct dyn_ftrace
*rec
;
2621 type
= filter_parse_regex(glob
, strlen(glob
), &search
, ¬);
2622 len
= strlen(search
);
2624 /* we do not support '!' for function probes */
2628 mutex_lock(&ftrace_lock
);
2630 if (unlikely(ftrace_disabled
))
2633 do_for_each_ftrace_rec(pg
, rec
) {
2635 if (!ftrace_match_record(rec
, NULL
, search
, len
, type
))
2638 entry
= kmalloc(sizeof(*entry
), GFP_KERNEL
);
2640 /* If we did not process any, then return error */
2651 * The caller might want to do something special
2652 * for each function we find. We call the callback
2653 * to give the caller an opportunity to do so.
2655 if (ops
->callback
) {
2656 if (ops
->callback(rec
->ip
, &entry
->data
) < 0) {
2657 /* caller does not like this func */
2664 entry
->ip
= rec
->ip
;
2666 key
= hash_long(entry
->ip
, FTRACE_HASH_BITS
);
2667 hlist_add_head_rcu(&entry
->node
, &ftrace_func_hash
[key
]);
2669 } while_for_each_ftrace_rec();
2670 __enable_ftrace_function_probe();
2673 mutex_unlock(&ftrace_lock
);
2679 PROBE_TEST_FUNC
= 1,
2684 __unregister_ftrace_function_probe(char *glob
, struct ftrace_probe_ops
*ops
,
2685 void *data
, int flags
)
2687 struct ftrace_func_probe
*entry
;
2688 struct hlist_node
*n
, *tmp
;
2689 char str
[KSYM_SYMBOL_LEN
];
2690 int type
= MATCH_FULL
;
2694 if (glob
&& (strcmp(glob
, "*") == 0 || !strlen(glob
)))
2699 type
= filter_parse_regex(glob
, strlen(glob
), &search
, ¬);
2700 len
= strlen(search
);
2702 /* we do not support '!' for function probes */
2707 mutex_lock(&ftrace_lock
);
2708 for (i
= 0; i
< FTRACE_FUNC_HASHSIZE
; i
++) {
2709 struct hlist_head
*hhd
= &ftrace_func_hash
[i
];
2711 hlist_for_each_entry_safe(entry
, n
, tmp
, hhd
, node
) {
2713 /* break up if statements for readability */
2714 if ((flags
& PROBE_TEST_FUNC
) && entry
->ops
!= ops
)
2717 if ((flags
& PROBE_TEST_DATA
) && entry
->data
!= data
)
2720 /* do this last, since it is the most expensive */
2722 kallsyms_lookup(entry
->ip
, NULL
, NULL
,
2724 if (!ftrace_match(str
, glob
, len
, type
))
2728 hlist_del(&entry
->node
);
2729 call_rcu(&entry
->rcu
, ftrace_free_entry_rcu
);
2732 __disable_ftrace_function_probe();
2733 mutex_unlock(&ftrace_lock
);
2737 unregister_ftrace_function_probe(char *glob
, struct ftrace_probe_ops
*ops
,
2740 __unregister_ftrace_function_probe(glob
, ops
, data
,
2741 PROBE_TEST_FUNC
| PROBE_TEST_DATA
);
2745 unregister_ftrace_function_probe_func(char *glob
, struct ftrace_probe_ops
*ops
)
2747 __unregister_ftrace_function_probe(glob
, ops
, NULL
, PROBE_TEST_FUNC
);
2750 void unregister_ftrace_function_probe_all(char *glob
)
2752 __unregister_ftrace_function_probe(glob
, NULL
, NULL
, 0);
2755 static LIST_HEAD(ftrace_commands
);
2756 static DEFINE_MUTEX(ftrace_cmd_mutex
);
2758 int register_ftrace_command(struct ftrace_func_command
*cmd
)
2760 struct ftrace_func_command
*p
;
2763 mutex_lock(&ftrace_cmd_mutex
);
2764 list_for_each_entry(p
, &ftrace_commands
, list
) {
2765 if (strcmp(cmd
->name
, p
->name
) == 0) {
2770 list_add(&cmd
->list
, &ftrace_commands
);
2772 mutex_unlock(&ftrace_cmd_mutex
);
2777 int unregister_ftrace_command(struct ftrace_func_command
*cmd
)
2779 struct ftrace_func_command
*p
, *n
;
2782 mutex_lock(&ftrace_cmd_mutex
);
2783 list_for_each_entry_safe(p
, n
, &ftrace_commands
, list
) {
2784 if (strcmp(cmd
->name
, p
->name
) == 0) {
2786 list_del_init(&p
->list
);
2791 mutex_unlock(&ftrace_cmd_mutex
);
2796 static int ftrace_process_regex(struct ftrace_hash
*hash
,
2797 char *buff
, int len
, int enable
)
2799 char *func
, *command
, *next
= buff
;
2800 struct ftrace_func_command
*p
;
2803 func
= strsep(&next
, ":");
2806 ret
= ftrace_match_records(hash
, func
, len
);
2816 command
= strsep(&next
, ":");
2818 mutex_lock(&ftrace_cmd_mutex
);
2819 list_for_each_entry(p
, &ftrace_commands
, list
) {
2820 if (strcmp(p
->name
, command
) == 0) {
2821 ret
= p
->func(hash
, func
, command
, next
, enable
);
2826 mutex_unlock(&ftrace_cmd_mutex
);
2832 ftrace_regex_write(struct file
*file
, const char __user
*ubuf
,
2833 size_t cnt
, loff_t
*ppos
, int enable
)
2835 struct ftrace_iterator
*iter
;
2836 struct trace_parser
*parser
;
2842 mutex_lock(&ftrace_regex_lock
);
2845 if (unlikely(ftrace_disabled
))
2848 if (file
->f_mode
& FMODE_READ
) {
2849 struct seq_file
*m
= file
->private_data
;
2852 iter
= file
->private_data
;
2854 parser
= &iter
->parser
;
2855 read
= trace_get_user(parser
, ubuf
, cnt
, ppos
);
2857 if (read
>= 0 && trace_parser_loaded(parser
) &&
2858 !trace_parser_cont(parser
)) {
2859 ret
= ftrace_process_regex(iter
->hash
, parser
->buffer
,
2860 parser
->idx
, enable
);
2861 trace_parser_clear(parser
);
2868 mutex_unlock(&ftrace_regex_lock
);
2874 ftrace_filter_write(struct file
*file
, const char __user
*ubuf
,
2875 size_t cnt
, loff_t
*ppos
)
2877 return ftrace_regex_write(file
, ubuf
, cnt
, ppos
, 1);
2881 ftrace_notrace_write(struct file
*file
, const char __user
*ubuf
,
2882 size_t cnt
, loff_t
*ppos
)
2884 return ftrace_regex_write(file
, ubuf
, cnt
, ppos
, 0);
2888 ftrace_set_regex(struct ftrace_ops
*ops
, unsigned char *buf
, int len
,
2889 int reset
, int enable
)
2891 struct ftrace_hash
**orig_hash
;
2892 struct ftrace_hash
*hash
;
2895 /* All global ops uses the global ops filters */
2896 if (ops
->flags
& FTRACE_OPS_FL_GLOBAL
)
2899 if (unlikely(ftrace_disabled
))
2903 orig_hash
= &ops
->filter_hash
;
2905 orig_hash
= &ops
->notrace_hash
;
2907 hash
= alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
, *orig_hash
);
2911 mutex_lock(&ftrace_regex_lock
);
2913 ftrace_filter_reset(hash
);
2915 ftrace_match_records(hash
, buf
, len
);
2917 mutex_lock(&ftrace_lock
);
2918 ret
= ftrace_hash_move(ops
, enable
, orig_hash
, hash
);
2919 if (!ret
&& ops
->flags
& FTRACE_OPS_FL_ENABLED
2921 ftrace_run_update_code(FTRACE_UPDATE_CALLS
);
2923 mutex_unlock(&ftrace_lock
);
2925 mutex_unlock(&ftrace_regex_lock
);
2927 free_ftrace_hash(hash
);
2932 * ftrace_set_filter - set a function to filter on in ftrace
2933 * @ops - the ops to set the filter with
2934 * @buf - the string that holds the function filter text.
2935 * @len - the length of the string.
2936 * @reset - non zero to reset all filters before applying this filter.
2938 * Filters denote which functions should be enabled when tracing is enabled.
2939 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2941 void ftrace_set_filter(struct ftrace_ops
*ops
, unsigned char *buf
,
2944 ftrace_set_regex(ops
, buf
, len
, reset
, 1);
2946 EXPORT_SYMBOL_GPL(ftrace_set_filter
);
2949 * ftrace_set_notrace - set a function to not trace in ftrace
2950 * @ops - the ops to set the notrace filter with
2951 * @buf - the string that holds the function notrace text.
2952 * @len - the length of the string.
2953 * @reset - non zero to reset all filters before applying this filter.
2955 * Notrace Filters denote which functions should not be enabled when tracing
2956 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2959 void ftrace_set_notrace(struct ftrace_ops
*ops
, unsigned char *buf
,
2962 ftrace_set_regex(ops
, buf
, len
, reset
, 0);
2964 EXPORT_SYMBOL_GPL(ftrace_set_notrace
);
2966 * ftrace_set_filter - set a function to filter on in ftrace
2967 * @ops - the ops to set the filter with
2968 * @buf - the string that holds the function filter text.
2969 * @len - the length of the string.
2970 * @reset - non zero to reset all filters before applying this filter.
2972 * Filters denote which functions should be enabled when tracing is enabled.
2973 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2975 void ftrace_set_global_filter(unsigned char *buf
, int len
, int reset
)
2977 ftrace_set_regex(&global_ops
, buf
, len
, reset
, 1);
2979 EXPORT_SYMBOL_GPL(ftrace_set_global_filter
);
2982 * ftrace_set_notrace - set a function to not trace in ftrace
2983 * @ops - the ops to set the notrace filter with
2984 * @buf - the string that holds the function notrace text.
2985 * @len - the length of the string.
2986 * @reset - non zero to reset all filters before applying this filter.
2988 * Notrace Filters denote which functions should not be enabled when tracing
2989 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2992 void ftrace_set_global_notrace(unsigned char *buf
, int len
, int reset
)
2994 ftrace_set_regex(&global_ops
, buf
, len
, reset
, 0);
2996 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace
);
2999 * command line interface to allow users to set filters on boot up.
3001 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
3002 static char ftrace_notrace_buf
[FTRACE_FILTER_SIZE
] __initdata
;
3003 static char ftrace_filter_buf
[FTRACE_FILTER_SIZE
] __initdata
;
3005 static int __init
set_ftrace_notrace(char *str
)
3007 strncpy(ftrace_notrace_buf
, str
, FTRACE_FILTER_SIZE
);
3010 __setup("ftrace_notrace=", set_ftrace_notrace
);
3012 static int __init
set_ftrace_filter(char *str
)
3014 strncpy(ftrace_filter_buf
, str
, FTRACE_FILTER_SIZE
);
3017 __setup("ftrace_filter=", set_ftrace_filter
);
3019 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3020 static char ftrace_graph_buf
[FTRACE_FILTER_SIZE
] __initdata
;
3021 static int ftrace_set_func(unsigned long *array
, int *idx
, char *buffer
);
3023 static int __init
set_graph_function(char *str
)
3025 strlcpy(ftrace_graph_buf
, str
, FTRACE_FILTER_SIZE
);
3028 __setup("ftrace_graph_filter=", set_graph_function
);
3030 static void __init
set_ftrace_early_graph(char *buf
)
3036 func
= strsep(&buf
, ",");
3037 /* we allow only one expression at a time */
3038 ret
= ftrace_set_func(ftrace_graph_funcs
, &ftrace_graph_count
,
3041 printk(KERN_DEBUG
"ftrace: function %s not "
3042 "traceable\n", func
);
3045 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3048 set_ftrace_early_filter(struct ftrace_ops
*ops
, char *buf
, int enable
)
3053 func
= strsep(&buf
, ",");
3054 ftrace_set_regex(ops
, func
, strlen(func
), 0, enable
);
3058 static void __init
set_ftrace_early_filters(void)
3060 if (ftrace_filter_buf
[0])
3061 set_ftrace_early_filter(&global_ops
, ftrace_filter_buf
, 1);
3062 if (ftrace_notrace_buf
[0])
3063 set_ftrace_early_filter(&global_ops
, ftrace_notrace_buf
, 0);
3064 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3065 if (ftrace_graph_buf
[0])
3066 set_ftrace_early_graph(ftrace_graph_buf
);
3067 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3071 ftrace_regex_release(struct inode
*inode
, struct file
*file
)
3073 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
3074 struct ftrace_iterator
*iter
;
3075 struct ftrace_hash
**orig_hash
;
3076 struct trace_parser
*parser
;
3080 mutex_lock(&ftrace_regex_lock
);
3081 if (file
->f_mode
& FMODE_READ
) {
3084 seq_release(inode
, file
);
3086 iter
= file
->private_data
;
3088 parser
= &iter
->parser
;
3089 if (trace_parser_loaded(parser
)) {
3090 parser
->buffer
[parser
->idx
] = 0;
3091 ftrace_match_records(iter
->hash
, parser
->buffer
, parser
->idx
);
3094 trace_parser_put(parser
);
3096 if (file
->f_mode
& FMODE_WRITE
) {
3097 filter_hash
= !!(iter
->flags
& FTRACE_ITER_FILTER
);
3100 orig_hash
= &iter
->ops
->filter_hash
;
3102 orig_hash
= &iter
->ops
->notrace_hash
;
3104 mutex_lock(&ftrace_lock
);
3105 ret
= ftrace_hash_move(iter
->ops
, filter_hash
,
3106 orig_hash
, iter
->hash
);
3107 if (!ret
&& (iter
->ops
->flags
& FTRACE_OPS_FL_ENABLED
)
3109 ftrace_run_update_code(FTRACE_UPDATE_CALLS
);
3111 mutex_unlock(&ftrace_lock
);
3113 free_ftrace_hash(iter
->hash
);
3116 mutex_unlock(&ftrace_regex_lock
);
3120 static const struct file_operations ftrace_avail_fops
= {
3121 .open
= ftrace_avail_open
,
3123 .llseek
= seq_lseek
,
3124 .release
= seq_release_private
,
3127 static const struct file_operations ftrace_enabled_fops
= {
3128 .open
= ftrace_enabled_open
,
3130 .llseek
= seq_lseek
,
3131 .release
= seq_release_private
,
3134 static const struct file_operations ftrace_filter_fops
= {
3135 .open
= ftrace_filter_open
,
3137 .write
= ftrace_filter_write
,
3138 .llseek
= ftrace_regex_lseek
,
3139 .release
= ftrace_regex_release
,
3142 static const struct file_operations ftrace_notrace_fops
= {
3143 .open
= ftrace_notrace_open
,
3145 .write
= ftrace_notrace_write
,
3146 .llseek
= ftrace_regex_lseek
,
3147 .release
= ftrace_regex_release
,
3150 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3152 static DEFINE_MUTEX(graph_lock
);
3154 int ftrace_graph_count
;
3155 int ftrace_graph_filter_enabled
;
3156 unsigned long ftrace_graph_funcs
[FTRACE_GRAPH_MAX_FUNCS
] __read_mostly
;
3159 __g_next(struct seq_file
*m
, loff_t
*pos
)
3161 if (*pos
>= ftrace_graph_count
)
3163 return &ftrace_graph_funcs
[*pos
];
3167 g_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
3170 return __g_next(m
, pos
);
3173 static void *g_start(struct seq_file
*m
, loff_t
*pos
)
3175 mutex_lock(&graph_lock
);
3177 /* Nothing, tell g_show to print all functions are enabled */
3178 if (!ftrace_graph_filter_enabled
&& !*pos
)
3181 return __g_next(m
, pos
);
3184 static void g_stop(struct seq_file
*m
, void *p
)
3186 mutex_unlock(&graph_lock
);
3189 static int g_show(struct seq_file
*m
, void *v
)
3191 unsigned long *ptr
= v
;
3196 if (ptr
== (unsigned long *)1) {
3197 seq_printf(m
, "#### all functions enabled ####\n");
3201 seq_printf(m
, "%ps\n", (void *)*ptr
);
3206 static const struct seq_operations ftrace_graph_seq_ops
= {
3214 ftrace_graph_open(struct inode
*inode
, struct file
*file
)
3218 if (unlikely(ftrace_disabled
))
3221 mutex_lock(&graph_lock
);
3222 if ((file
->f_mode
& FMODE_WRITE
) &&
3223 (file
->f_flags
& O_TRUNC
)) {
3224 ftrace_graph_filter_enabled
= 0;
3225 ftrace_graph_count
= 0;
3226 memset(ftrace_graph_funcs
, 0, sizeof(ftrace_graph_funcs
));
3228 mutex_unlock(&graph_lock
);
3230 if (file
->f_mode
& FMODE_READ
)
3231 ret
= seq_open(file
, &ftrace_graph_seq_ops
);
3237 ftrace_graph_release(struct inode
*inode
, struct file
*file
)
3239 if (file
->f_mode
& FMODE_READ
)
3240 seq_release(inode
, file
);
3245 ftrace_set_func(unsigned long *array
, int *idx
, char *buffer
)
3247 struct dyn_ftrace
*rec
;
3248 struct ftrace_page
*pg
;
3257 type
= filter_parse_regex(buffer
, strlen(buffer
), &search
, ¬);
3258 if (!not && *idx
>= FTRACE_GRAPH_MAX_FUNCS
)
3261 search_len
= strlen(search
);
3263 mutex_lock(&ftrace_lock
);
3265 if (unlikely(ftrace_disabled
)) {
3266 mutex_unlock(&ftrace_lock
);
3270 do_for_each_ftrace_rec(pg
, rec
) {
3272 if (rec
->flags
& FTRACE_FL_FREE
)
3275 if (ftrace_match_record(rec
, NULL
, search
, search_len
, type
)) {
3276 /* if it is in the array */
3278 for (i
= 0; i
< *idx
; i
++) {
3279 if (array
[i
] == rec
->ip
) {
3288 array
[(*idx
)++] = rec
->ip
;
3289 if (*idx
>= FTRACE_GRAPH_MAX_FUNCS
)
3294 array
[i
] = array
[--(*idx
)];
3300 } while_for_each_ftrace_rec();
3302 mutex_unlock(&ftrace_lock
);
3307 ftrace_graph_filter_enabled
= 1;
3312 ftrace_graph_write(struct file
*file
, const char __user
*ubuf
,
3313 size_t cnt
, loff_t
*ppos
)
3315 struct trace_parser parser
;
3321 mutex_lock(&graph_lock
);
3323 if (trace_parser_get_init(&parser
, FTRACE_BUFF_MAX
)) {
3328 read
= trace_get_user(&parser
, ubuf
, cnt
, ppos
);
3330 if (read
>= 0 && trace_parser_loaded((&parser
))) {
3331 parser
.buffer
[parser
.idx
] = 0;
3333 /* we allow only one expression at a time */
3334 ret
= ftrace_set_func(ftrace_graph_funcs
, &ftrace_graph_count
,
3343 trace_parser_put(&parser
);
3345 mutex_unlock(&graph_lock
);
3350 static const struct file_operations ftrace_graph_fops
= {
3351 .open
= ftrace_graph_open
,
3353 .write
= ftrace_graph_write
,
3354 .release
= ftrace_graph_release
,
3355 .llseek
= seq_lseek
,
3357 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3359 static __init
int ftrace_init_dyn_debugfs(struct dentry
*d_tracer
)
3362 trace_create_file("available_filter_functions", 0444,
3363 d_tracer
, NULL
, &ftrace_avail_fops
);
3365 trace_create_file("enabled_functions", 0444,
3366 d_tracer
, NULL
, &ftrace_enabled_fops
);
3368 trace_create_file("set_ftrace_filter", 0644, d_tracer
,
3369 NULL
, &ftrace_filter_fops
);
3371 trace_create_file("set_ftrace_notrace", 0644, d_tracer
,
3372 NULL
, &ftrace_notrace_fops
);
3374 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3375 trace_create_file("set_graph_function", 0444, d_tracer
,
3377 &ftrace_graph_fops
);
3378 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3383 static int ftrace_process_locs(struct module
*mod
,
3384 unsigned long *start
,
3389 unsigned long flags
= 0; /* Shut up gcc */
3391 mutex_lock(&ftrace_lock
);
3394 addr
= ftrace_call_adjust(*p
++);
3396 * Some architecture linkers will pad between
3397 * the different mcount_loc sections of different
3398 * object files to satisfy alignments.
3399 * Skip any NULL pointers.
3403 ftrace_record_ip(addr
);
3407 * We only need to disable interrupts on start up
3408 * because we are modifying code that an interrupt
3409 * may execute, and the modification is not atomic.
3410 * But for modules, nothing runs the code we modify
3411 * until we are finished with it, and there's no
3412 * reason to cause large interrupt latencies while we do it.
3415 local_irq_save(flags
);
3416 ftrace_update_code(mod
);
3418 local_irq_restore(flags
);
3419 mutex_unlock(&ftrace_lock
);
3424 #ifdef CONFIG_MODULES
3425 void ftrace_release_mod(struct module
*mod
)
3427 struct dyn_ftrace
*rec
;
3428 struct ftrace_page
*pg
;
3430 mutex_lock(&ftrace_lock
);
3432 if (ftrace_disabled
)
3435 do_for_each_ftrace_rec(pg
, rec
) {
3436 if (within_module_core(rec
->ip
, mod
)) {
3438 * rec->ip is changed in ftrace_free_rec()
3439 * It should not between s and e if record was freed.
3441 FTRACE_WARN_ON(rec
->flags
& FTRACE_FL_FREE
);
3442 ftrace_free_rec(rec
);
3444 } while_for_each_ftrace_rec();
3446 mutex_unlock(&ftrace_lock
);
3449 static void ftrace_init_module(struct module
*mod
,
3450 unsigned long *start
, unsigned long *end
)
3452 if (ftrace_disabled
|| start
== end
)
3454 ftrace_process_locs(mod
, start
, end
);
3457 static int ftrace_module_notify(struct notifier_block
*self
,
3458 unsigned long val
, void *data
)
3460 struct module
*mod
= data
;
3463 case MODULE_STATE_COMING
:
3464 ftrace_init_module(mod
, mod
->ftrace_callsites
,
3465 mod
->ftrace_callsites
+
3466 mod
->num_ftrace_callsites
);
3468 case MODULE_STATE_GOING
:
3469 ftrace_release_mod(mod
);
3476 static int ftrace_module_notify(struct notifier_block
*self
,
3477 unsigned long val
, void *data
)
3481 #endif /* CONFIG_MODULES */
3483 struct notifier_block ftrace_module_nb
= {
3484 .notifier_call
= ftrace_module_notify
,
3488 extern unsigned long __start_mcount_loc
[];
3489 extern unsigned long __stop_mcount_loc
[];
3491 void __init
ftrace_init(void)
3493 unsigned long count
, addr
, flags
;
3496 /* Keep the ftrace pointer to the stub */
3497 addr
= (unsigned long)ftrace_stub
;
3499 local_irq_save(flags
);
3500 ftrace_dyn_arch_init(&addr
);
3501 local_irq_restore(flags
);
3503 /* ftrace_dyn_arch_init places the return code in addr */
3507 count
= __stop_mcount_loc
- __start_mcount_loc
;
3509 ret
= ftrace_dyn_table_alloc(count
);
3513 last_ftrace_enabled
= ftrace_enabled
= 1;
3515 ret
= ftrace_process_locs(NULL
,
3519 ret
= register_module_notifier(&ftrace_module_nb
);
3521 pr_warning("Failed to register trace ftrace module notifier\n");
3523 set_ftrace_early_filters();
3527 ftrace_disabled
= 1;
3532 static struct ftrace_ops global_ops
= {
3533 .func
= ftrace_stub
,
3536 static int __init
ftrace_nodyn_init(void)
3541 device_initcall(ftrace_nodyn_init
);
3543 static inline int ftrace_init_dyn_debugfs(struct dentry
*d_tracer
) { return 0; }
3544 static inline void ftrace_startup_enable(int command
) { }
3545 /* Keep as macros so we do not need to define the commands */
3546 # define ftrace_startup(ops, command) \
3548 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
3551 # define ftrace_shutdown(ops, command) do { } while (0)
3552 # define ftrace_startup_sysctl() do { } while (0)
3553 # define ftrace_shutdown_sysctl() do { } while (0)
3556 ftrace_ops_test(struct ftrace_ops
*ops
, unsigned long ip
)
3561 #endif /* CONFIG_DYNAMIC_FTRACE */
3564 ftrace_ops_list_func(unsigned long ip
, unsigned long parent_ip
)
3566 struct ftrace_ops
*op
;
3568 if (unlikely(trace_recursion_test(TRACE_INTERNAL_BIT
)))
3571 trace_recursion_set(TRACE_INTERNAL_BIT
);
3573 * Some of the ops may be dynamically allocated,
3574 * they must be freed after a synchronize_sched().
3576 preempt_disable_notrace();
3577 op
= rcu_dereference_raw(ftrace_ops_list
);
3578 while (op
!= &ftrace_list_end
) {
3579 if (ftrace_ops_test(op
, ip
))
3580 op
->func(ip
, parent_ip
);
3581 op
= rcu_dereference_raw(op
->next
);
3583 preempt_enable_notrace();
3584 trace_recursion_clear(TRACE_INTERNAL_BIT
);
3587 static void clear_ftrace_swapper(void)
3589 struct task_struct
*p
;
3593 for_each_online_cpu(cpu
) {
3595 clear_tsk_trace_trace(p
);
3600 static void set_ftrace_swapper(void)
3602 struct task_struct
*p
;
3606 for_each_online_cpu(cpu
) {
3608 set_tsk_trace_trace(p
);
3613 static void clear_ftrace_pid(struct pid
*pid
)
3615 struct task_struct
*p
;
3618 do_each_pid_task(pid
, PIDTYPE_PID
, p
) {
3619 clear_tsk_trace_trace(p
);
3620 } while_each_pid_task(pid
, PIDTYPE_PID
, p
);
3626 static void set_ftrace_pid(struct pid
*pid
)
3628 struct task_struct
*p
;
3631 do_each_pid_task(pid
, PIDTYPE_PID
, p
) {
3632 set_tsk_trace_trace(p
);
3633 } while_each_pid_task(pid
, PIDTYPE_PID
, p
);
3637 static void clear_ftrace_pid_task(struct pid
*pid
)
3639 if (pid
== ftrace_swapper_pid
)
3640 clear_ftrace_swapper();
3642 clear_ftrace_pid(pid
);
3645 static void set_ftrace_pid_task(struct pid
*pid
)
3647 if (pid
== ftrace_swapper_pid
)
3648 set_ftrace_swapper();
3650 set_ftrace_pid(pid
);
3653 static int ftrace_pid_add(int p
)
3656 struct ftrace_pid
*fpid
;
3659 mutex_lock(&ftrace_lock
);
3662 pid
= ftrace_swapper_pid
;
3664 pid
= find_get_pid(p
);
3671 list_for_each_entry(fpid
, &ftrace_pids
, list
)
3672 if (fpid
->pid
== pid
)
3677 fpid
= kmalloc(sizeof(*fpid
), GFP_KERNEL
);
3681 list_add(&fpid
->list
, &ftrace_pids
);
3684 set_ftrace_pid_task(pid
);
3686 ftrace_update_pid_func();
3687 ftrace_startup_enable(0);
3689 mutex_unlock(&ftrace_lock
);
3693 if (pid
!= ftrace_swapper_pid
)
3697 mutex_unlock(&ftrace_lock
);
3701 static void ftrace_pid_reset(void)
3703 struct ftrace_pid
*fpid
, *safe
;
3705 mutex_lock(&ftrace_lock
);
3706 list_for_each_entry_safe(fpid
, safe
, &ftrace_pids
, list
) {
3707 struct pid
*pid
= fpid
->pid
;
3709 clear_ftrace_pid_task(pid
);
3711 list_del(&fpid
->list
);
3715 ftrace_update_pid_func();
3716 ftrace_startup_enable(0);
3718 mutex_unlock(&ftrace_lock
);
3721 static void *fpid_start(struct seq_file
*m
, loff_t
*pos
)
3723 mutex_lock(&ftrace_lock
);
3725 if (list_empty(&ftrace_pids
) && (!*pos
))
3728 return seq_list_start(&ftrace_pids
, *pos
);
3731 static void *fpid_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
3736 return seq_list_next(v
, &ftrace_pids
, pos
);
3739 static void fpid_stop(struct seq_file
*m
, void *p
)
3741 mutex_unlock(&ftrace_lock
);
3744 static int fpid_show(struct seq_file
*m
, void *v
)
3746 const struct ftrace_pid
*fpid
= list_entry(v
, struct ftrace_pid
, list
);
3748 if (v
== (void *)1) {
3749 seq_printf(m
, "no pid\n");
3753 if (fpid
->pid
== ftrace_swapper_pid
)
3754 seq_printf(m
, "swapper tasks\n");
3756 seq_printf(m
, "%u\n", pid_vnr(fpid
->pid
));
3761 static const struct seq_operations ftrace_pid_sops
= {
3762 .start
= fpid_start
,
3769 ftrace_pid_open(struct inode
*inode
, struct file
*file
)
3773 if ((file
->f_mode
& FMODE_WRITE
) &&
3774 (file
->f_flags
& O_TRUNC
))
3777 if (file
->f_mode
& FMODE_READ
)
3778 ret
= seq_open(file
, &ftrace_pid_sops
);
3784 ftrace_pid_write(struct file
*filp
, const char __user
*ubuf
,
3785 size_t cnt
, loff_t
*ppos
)
3791 if (cnt
>= sizeof(buf
))
3794 if (copy_from_user(&buf
, ubuf
, cnt
))
3800 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
3801 * to clean the filter quietly.
3803 tmp
= strstrip(buf
);
3804 if (strlen(tmp
) == 0)
3807 ret
= strict_strtol(tmp
, 10, &val
);
3811 ret
= ftrace_pid_add(val
);
3813 return ret
? ret
: cnt
;
3817 ftrace_pid_release(struct inode
*inode
, struct file
*file
)
3819 if (file
->f_mode
& FMODE_READ
)
3820 seq_release(inode
, file
);
3825 static const struct file_operations ftrace_pid_fops
= {
3826 .open
= ftrace_pid_open
,
3827 .write
= ftrace_pid_write
,
3829 .llseek
= seq_lseek
,
3830 .release
= ftrace_pid_release
,
3833 static __init
int ftrace_init_debugfs(void)
3835 struct dentry
*d_tracer
;
3837 d_tracer
= tracing_init_dentry();
3841 ftrace_init_dyn_debugfs(d_tracer
);
3843 trace_create_file("set_ftrace_pid", 0644, d_tracer
,
3844 NULL
, &ftrace_pid_fops
);
3846 ftrace_profile_debugfs(d_tracer
);
3850 fs_initcall(ftrace_init_debugfs
);
3853 * ftrace_kill - kill ftrace
3855 * This function should be used by panic code. It stops ftrace
3856 * but in a not so nice way. If you need to simply kill ftrace
3857 * from a non-atomic section, use ftrace_kill.
3859 void ftrace_kill(void)
3861 ftrace_disabled
= 1;
3863 clear_ftrace_function();
3867 * Test if ftrace is dead or not.
3869 int ftrace_is_dead(void)
3871 return ftrace_disabled
;
3875 * register_ftrace_function - register a function for profiling
3876 * @ops - ops structure that holds the function for profiling.
3878 * Register a function to be called by all functions in the
3881 * Note: @ops->func and all the functions it calls must be labeled
3882 * with "notrace", otherwise it will go into a
3885 int register_ftrace_function(struct ftrace_ops
*ops
)
3889 mutex_lock(&ftrace_lock
);
3891 if (unlikely(ftrace_disabled
))
3894 ret
= __register_ftrace_function(ops
);
3896 ret
= ftrace_startup(ops
, 0);
3900 mutex_unlock(&ftrace_lock
);
3903 EXPORT_SYMBOL_GPL(register_ftrace_function
);
3906 * unregister_ftrace_function - unregister a function for profiling.
3907 * @ops - ops structure that holds the function to unregister
3909 * Unregister a function that was added to be called by ftrace profiling.
3911 int unregister_ftrace_function(struct ftrace_ops
*ops
)
3915 mutex_lock(&ftrace_lock
);
3916 ret
= __unregister_ftrace_function(ops
);
3918 ftrace_shutdown(ops
, 0);
3919 mutex_unlock(&ftrace_lock
);
3923 EXPORT_SYMBOL_GPL(unregister_ftrace_function
);
3926 ftrace_enable_sysctl(struct ctl_table
*table
, int write
,
3927 void __user
*buffer
, size_t *lenp
,
3932 mutex_lock(&ftrace_lock
);
3934 if (unlikely(ftrace_disabled
))
3937 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
3939 if (ret
|| !write
|| (last_ftrace_enabled
== !!ftrace_enabled
))
3942 last_ftrace_enabled
= !!ftrace_enabled
;
3944 if (ftrace_enabled
) {
3946 ftrace_startup_sysctl();
3948 /* we are starting ftrace again */
3949 if (ftrace_ops_list
!= &ftrace_list_end
) {
3950 if (ftrace_ops_list
->next
== &ftrace_list_end
)
3951 ftrace_trace_function
= ftrace_ops_list
->func
;
3953 ftrace_trace_function
= ftrace_ops_list_func
;
3957 /* stopping ftrace calls (just send to ftrace_stub) */
3958 ftrace_trace_function
= ftrace_stub
;
3960 ftrace_shutdown_sysctl();
3964 mutex_unlock(&ftrace_lock
);
3968 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3970 static int ftrace_graph_active
;
3971 static struct notifier_block ftrace_suspend_notifier
;
3973 int ftrace_graph_entry_stub(struct ftrace_graph_ent
*trace
)
3978 /* The callbacks that hook a function */
3979 trace_func_graph_ret_t ftrace_graph_return
=
3980 (trace_func_graph_ret_t
)ftrace_stub
;
3981 trace_func_graph_ent_t ftrace_graph_entry
= ftrace_graph_entry_stub
;
3983 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
3984 static int alloc_retstack_tasklist(struct ftrace_ret_stack
**ret_stack_list
)
3988 unsigned long flags
;
3989 int start
= 0, end
= FTRACE_RETSTACK_ALLOC_SIZE
;
3990 struct task_struct
*g
, *t
;
3992 for (i
= 0; i
< FTRACE_RETSTACK_ALLOC_SIZE
; i
++) {
3993 ret_stack_list
[i
] = kmalloc(FTRACE_RETFUNC_DEPTH
3994 * sizeof(struct ftrace_ret_stack
),
3996 if (!ret_stack_list
[i
]) {
4004 read_lock_irqsave(&tasklist_lock
, flags
);
4005 do_each_thread(g
, t
) {
4011 if (t
->ret_stack
== NULL
) {
4012 atomic_set(&t
->tracing_graph_pause
, 0);
4013 atomic_set(&t
->trace_overrun
, 0);
4014 t
->curr_ret_stack
= -1;
4015 /* Make sure the tasks see the -1 first: */
4017 t
->ret_stack
= ret_stack_list
[start
++];
4019 } while_each_thread(g
, t
);
4022 read_unlock_irqrestore(&tasklist_lock
, flags
);
4024 for (i
= start
; i
< end
; i
++)
4025 kfree(ret_stack_list
[i
]);
4030 ftrace_graph_probe_sched_switch(void *ignore
,
4031 struct task_struct
*prev
, struct task_struct
*next
)
4033 unsigned long long timestamp
;
4037 * Does the user want to count the time a function was asleep.
4038 * If so, do not update the time stamps.
4040 if (trace_flags
& TRACE_ITER_SLEEP_TIME
)
4043 timestamp
= trace_clock_local();
4045 prev
->ftrace_timestamp
= timestamp
;
4047 /* only process tasks that we timestamped */
4048 if (!next
->ftrace_timestamp
)
4052 * Update all the counters in next to make up for the
4053 * time next was sleeping.
4055 timestamp
-= next
->ftrace_timestamp
;
4057 for (index
= next
->curr_ret_stack
; index
>= 0; index
--)
4058 next
->ret_stack
[index
].calltime
+= timestamp
;
4061 /* Allocate a return stack for each task */
4062 static int start_graph_tracing(void)
4064 struct ftrace_ret_stack
**ret_stack_list
;
4067 ret_stack_list
= kmalloc(FTRACE_RETSTACK_ALLOC_SIZE
*
4068 sizeof(struct ftrace_ret_stack
*),
4071 if (!ret_stack_list
)
4074 /* The cpu_boot init_task->ret_stack will never be freed */
4075 for_each_online_cpu(cpu
) {
4076 if (!idle_task(cpu
)->ret_stack
)
4077 ftrace_graph_init_idle_task(idle_task(cpu
), cpu
);
4081 ret
= alloc_retstack_tasklist(ret_stack_list
);
4082 } while (ret
== -EAGAIN
);
4085 ret
= register_trace_sched_switch(ftrace_graph_probe_sched_switch
, NULL
);
4087 pr_info("ftrace_graph: Couldn't activate tracepoint"
4088 " probe to kernel_sched_switch\n");
4091 kfree(ret_stack_list
);
4096 * Hibernation protection.
4097 * The state of the current task is too much unstable during
4098 * suspend/restore to disk. We want to protect against that.
4101 ftrace_suspend_notifier_call(struct notifier_block
*bl
, unsigned long state
,
4105 case PM_HIBERNATION_PREPARE
:
4106 pause_graph_tracing();
4109 case PM_POST_HIBERNATION
:
4110 unpause_graph_tracing();
4116 int register_ftrace_graph(trace_func_graph_ret_t retfunc
,
4117 trace_func_graph_ent_t entryfunc
)
4121 mutex_lock(&ftrace_lock
);
4123 /* we currently allow only one tracer registered at a time */
4124 if (ftrace_graph_active
) {
4129 ftrace_suspend_notifier
.notifier_call
= ftrace_suspend_notifier_call
;
4130 register_pm_notifier(&ftrace_suspend_notifier
);
4132 ftrace_graph_active
++;
4133 ret
= start_graph_tracing();
4135 ftrace_graph_active
--;
4139 ftrace_graph_return
= retfunc
;
4140 ftrace_graph_entry
= entryfunc
;
4142 ret
= ftrace_startup(&global_ops
, FTRACE_START_FUNC_RET
);
4145 mutex_unlock(&ftrace_lock
);
4149 void unregister_ftrace_graph(void)
4151 mutex_lock(&ftrace_lock
);
4153 if (unlikely(!ftrace_graph_active
))
4156 ftrace_graph_active
--;
4157 ftrace_graph_return
= (trace_func_graph_ret_t
)ftrace_stub
;
4158 ftrace_graph_entry
= ftrace_graph_entry_stub
;
4159 ftrace_shutdown(&global_ops
, FTRACE_STOP_FUNC_RET
);
4160 unregister_pm_notifier(&ftrace_suspend_notifier
);
4161 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch
, NULL
);
4164 mutex_unlock(&ftrace_lock
);
4167 static DEFINE_PER_CPU(struct ftrace_ret_stack
*, idle_ret_stack
);
4170 graph_init_task(struct task_struct
*t
, struct ftrace_ret_stack
*ret_stack
)
4172 atomic_set(&t
->tracing_graph_pause
, 0);
4173 atomic_set(&t
->trace_overrun
, 0);
4174 t
->ftrace_timestamp
= 0;
4175 /* make curr_ret_stack visible before we add the ret_stack */
4177 t
->ret_stack
= ret_stack
;
4181 * Allocate a return stack for the idle task. May be the first
4182 * time through, or it may be done by CPU hotplug online.
4184 void ftrace_graph_init_idle_task(struct task_struct
*t
, int cpu
)
4186 t
->curr_ret_stack
= -1;
4188 * The idle task has no parent, it either has its own
4189 * stack or no stack at all.
4192 WARN_ON(t
->ret_stack
!= per_cpu(idle_ret_stack
, cpu
));
4194 if (ftrace_graph_active
) {
4195 struct ftrace_ret_stack
*ret_stack
;
4197 ret_stack
= per_cpu(idle_ret_stack
, cpu
);
4199 ret_stack
= kmalloc(FTRACE_RETFUNC_DEPTH
4200 * sizeof(struct ftrace_ret_stack
),
4204 per_cpu(idle_ret_stack
, cpu
) = ret_stack
;
4206 graph_init_task(t
, ret_stack
);
4210 /* Allocate a return stack for newly created task */
4211 void ftrace_graph_init_task(struct task_struct
*t
)
4213 /* Make sure we do not use the parent ret_stack */
4214 t
->ret_stack
= NULL
;
4215 t
->curr_ret_stack
= -1;
4217 if (ftrace_graph_active
) {
4218 struct ftrace_ret_stack
*ret_stack
;
4220 ret_stack
= kmalloc(FTRACE_RETFUNC_DEPTH
4221 * sizeof(struct ftrace_ret_stack
),
4225 graph_init_task(t
, ret_stack
);
4229 void ftrace_graph_exit_task(struct task_struct
*t
)
4231 struct ftrace_ret_stack
*ret_stack
= t
->ret_stack
;
4233 t
->ret_stack
= NULL
;
4234 /* NULL must become visible to IRQs before we free it: */
4240 void ftrace_graph_stop(void)