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
;
950 struct ftrace_func_entry
{
951 struct hlist_node hlist
;
956 unsigned long size_bits
;
957 struct hlist_head
*buckets
;
963 * We make these constant because no one should touch them,
964 * but they are used as the default "empty hash", to avoid allocating
965 * it all the time. These are in a read only section such that if
966 * anyone does try to modify it, it will cause an exception.
968 static const struct hlist_head empty_buckets
[1];
969 static const struct ftrace_hash empty_hash
= {
970 .buckets
= (struct hlist_head
*)empty_buckets
,
972 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
974 static struct ftrace_ops global_ops
= {
976 .notrace_hash
= EMPTY_HASH
,
977 .filter_hash
= EMPTY_HASH
,
980 static struct dyn_ftrace
*ftrace_new_addrs
;
982 static DEFINE_MUTEX(ftrace_regex_lock
);
985 struct ftrace_page
*next
;
987 struct dyn_ftrace records
[];
990 #define ENTRIES_PER_PAGE \
991 ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
993 /* estimate from running different kernels */
994 #define NR_TO_INIT 10000
996 static struct ftrace_page
*ftrace_pages_start
;
997 static struct ftrace_page
*ftrace_pages
;
999 static struct dyn_ftrace
*ftrace_free_records
;
1001 static struct ftrace_func_entry
*
1002 ftrace_lookup_ip(struct ftrace_hash
*hash
, unsigned long ip
)
1005 struct ftrace_func_entry
*entry
;
1006 struct hlist_head
*hhd
;
1007 struct hlist_node
*n
;
1012 if (hash
->size_bits
> 0)
1013 key
= hash_long(ip
, hash
->size_bits
);
1017 hhd
= &hash
->buckets
[key
];
1019 hlist_for_each_entry_rcu(entry
, n
, hhd
, hlist
) {
1020 if (entry
->ip
== ip
)
1026 static void __add_hash_entry(struct ftrace_hash
*hash
,
1027 struct ftrace_func_entry
*entry
)
1029 struct hlist_head
*hhd
;
1032 if (hash
->size_bits
)
1033 key
= hash_long(entry
->ip
, hash
->size_bits
);
1037 hhd
= &hash
->buckets
[key
];
1038 hlist_add_head(&entry
->hlist
, hhd
);
1042 static int add_hash_entry(struct ftrace_hash
*hash
, unsigned long ip
)
1044 struct ftrace_func_entry
*entry
;
1046 entry
= kmalloc(sizeof(*entry
), GFP_KERNEL
);
1051 __add_hash_entry(hash
, entry
);
1057 free_hash_entry(struct ftrace_hash
*hash
,
1058 struct ftrace_func_entry
*entry
)
1060 hlist_del(&entry
->hlist
);
1066 remove_hash_entry(struct ftrace_hash
*hash
,
1067 struct ftrace_func_entry
*entry
)
1069 hlist_del(&entry
->hlist
);
1073 static void ftrace_hash_clear(struct ftrace_hash
*hash
)
1075 struct hlist_head
*hhd
;
1076 struct hlist_node
*tp
, *tn
;
1077 struct ftrace_func_entry
*entry
;
1078 int size
= 1 << hash
->size_bits
;
1084 for (i
= 0; i
< size
; i
++) {
1085 hhd
= &hash
->buckets
[i
];
1086 hlist_for_each_entry_safe(entry
, tp
, tn
, hhd
, hlist
)
1087 free_hash_entry(hash
, entry
);
1089 FTRACE_WARN_ON(hash
->count
);
1092 static void free_ftrace_hash(struct ftrace_hash
*hash
)
1094 if (!hash
|| hash
== EMPTY_HASH
)
1096 ftrace_hash_clear(hash
);
1097 kfree(hash
->buckets
);
1101 static void __free_ftrace_hash_rcu(struct rcu_head
*rcu
)
1103 struct ftrace_hash
*hash
;
1105 hash
= container_of(rcu
, struct ftrace_hash
, rcu
);
1106 free_ftrace_hash(hash
);
1109 static void free_ftrace_hash_rcu(struct ftrace_hash
*hash
)
1111 if (!hash
|| hash
== EMPTY_HASH
)
1113 call_rcu_sched(&hash
->rcu
, __free_ftrace_hash_rcu
);
1116 static struct ftrace_hash
*alloc_ftrace_hash(int size_bits
)
1118 struct ftrace_hash
*hash
;
1121 hash
= kzalloc(sizeof(*hash
), GFP_KERNEL
);
1125 size
= 1 << size_bits
;
1126 hash
->buckets
= kzalloc(sizeof(*hash
->buckets
) * size
, GFP_KERNEL
);
1128 if (!hash
->buckets
) {
1133 hash
->size_bits
= size_bits
;
1138 static struct ftrace_hash
*
1139 alloc_and_copy_ftrace_hash(int size_bits
, struct ftrace_hash
*hash
)
1141 struct ftrace_func_entry
*entry
;
1142 struct ftrace_hash
*new_hash
;
1143 struct hlist_node
*tp
;
1148 new_hash
= alloc_ftrace_hash(size_bits
);
1153 if (!hash
|| !hash
->count
)
1156 size
= 1 << hash
->size_bits
;
1157 for (i
= 0; i
< size
; i
++) {
1158 hlist_for_each_entry(entry
, tp
, &hash
->buckets
[i
], hlist
) {
1159 ret
= add_hash_entry(new_hash
, entry
->ip
);
1165 FTRACE_WARN_ON(new_hash
->count
!= hash
->count
);
1170 free_ftrace_hash(new_hash
);
1175 ftrace_hash_rec_disable(struct ftrace_ops
*ops
, int filter_hash
);
1177 ftrace_hash_rec_enable(struct ftrace_ops
*ops
, int filter_hash
);
1180 ftrace_hash_move(struct ftrace_ops
*ops
, int enable
,
1181 struct ftrace_hash
**dst
, struct ftrace_hash
*src
)
1183 struct ftrace_func_entry
*entry
;
1184 struct hlist_node
*tp
, *tn
;
1185 struct hlist_head
*hhd
;
1186 struct ftrace_hash
*old_hash
;
1187 struct ftrace_hash
*new_hash
;
1189 int size
= src
->count
;
1195 * Remove the current set, update the hash and add
1198 ftrace_hash_rec_disable(ops
, enable
);
1201 * If the new source is empty, just free dst and assign it
1205 free_ftrace_hash_rcu(*dst
);
1206 rcu_assign_pointer(*dst
, EMPTY_HASH
);
1207 /* still need to update the function records */
1213 * Make the hash size about 1/2 the # found
1215 for (size
/= 2; size
; size
>>= 1)
1218 /* Don't allocate too much */
1219 if (bits
> FTRACE_HASH_MAX_BITS
)
1220 bits
= FTRACE_HASH_MAX_BITS
;
1223 new_hash
= alloc_ftrace_hash(bits
);
1227 size
= 1 << src
->size_bits
;
1228 for (i
= 0; i
< size
; i
++) {
1229 hhd
= &src
->buckets
[i
];
1230 hlist_for_each_entry_safe(entry
, tp
, tn
, hhd
, hlist
) {
1232 key
= hash_long(entry
->ip
, bits
);
1235 remove_hash_entry(src
, entry
);
1236 __add_hash_entry(new_hash
, entry
);
1241 rcu_assign_pointer(*dst
, new_hash
);
1242 free_ftrace_hash_rcu(old_hash
);
1247 * Enable regardless of ret:
1248 * On success, we enable the new hash.
1249 * On failure, we re-enable the original hash.
1251 ftrace_hash_rec_enable(ops
, enable
);
1257 * Test the hashes for this ops to see if we want to call
1258 * the ops->func or not.
1260 * It's a match if the ip is in the ops->filter_hash or
1261 * the filter_hash does not exist or is empty,
1263 * the ip is not in the ops->notrace_hash.
1265 * This needs to be called with preemption disabled as
1266 * the hashes are freed with call_rcu_sched().
1269 ftrace_ops_test(struct ftrace_ops
*ops
, unsigned long ip
)
1271 struct ftrace_hash
*filter_hash
;
1272 struct ftrace_hash
*notrace_hash
;
1275 filter_hash
= rcu_dereference_raw(ops
->filter_hash
);
1276 notrace_hash
= rcu_dereference_raw(ops
->notrace_hash
);
1278 if ((!filter_hash
|| !filter_hash
->count
||
1279 ftrace_lookup_ip(filter_hash
, ip
)) &&
1280 (!notrace_hash
|| !notrace_hash
->count
||
1281 !ftrace_lookup_ip(notrace_hash
, ip
)))
1290 * This is a double for. Do not use 'break' to break out of the loop,
1291 * you must use a goto.
1293 #define do_for_each_ftrace_rec(pg, rec) \
1294 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1296 for (_____i = 0; _____i < pg->index; _____i++) { \
1297 rec = &pg->records[_____i];
1299 #define while_for_each_ftrace_rec() \
1304 * ftrace_location - return true if the ip giving is a traced location
1305 * @ip: the instruction pointer to check
1307 * Returns 1 if @ip given is a pointer to a ftrace location.
1308 * That is, the instruction that is either a NOP or call to
1309 * the function tracer. It checks the ftrace internal tables to
1310 * determine if the address belongs or not.
1312 int ftrace_location(unsigned long ip
)
1314 struct ftrace_page
*pg
;
1315 struct dyn_ftrace
*rec
;
1317 do_for_each_ftrace_rec(pg
, rec
) {
1320 } while_for_each_ftrace_rec();
1325 static void __ftrace_hash_rec_update(struct ftrace_ops
*ops
,
1329 struct ftrace_hash
*hash
;
1330 struct ftrace_hash
*other_hash
;
1331 struct ftrace_page
*pg
;
1332 struct dyn_ftrace
*rec
;
1336 /* Only update if the ops has been registered */
1337 if (!(ops
->flags
& FTRACE_OPS_FL_ENABLED
))
1341 * In the filter_hash case:
1342 * If the count is zero, we update all records.
1343 * Otherwise we just update the items in the hash.
1345 * In the notrace_hash case:
1346 * We enable the update in the hash.
1347 * As disabling notrace means enabling the tracing,
1348 * and enabling notrace means disabling, the inc variable
1352 hash
= ops
->filter_hash
;
1353 other_hash
= ops
->notrace_hash
;
1354 if (!hash
|| !hash
->count
)
1358 hash
= ops
->notrace_hash
;
1359 other_hash
= ops
->filter_hash
;
1361 * If the notrace hash has no items,
1362 * then there's nothing to do.
1364 if (hash
&& !hash
->count
)
1368 do_for_each_ftrace_rec(pg
, rec
) {
1369 int in_other_hash
= 0;
1375 * Only the filter_hash affects all records.
1376 * Update if the record is not in the notrace hash.
1378 if (!other_hash
|| !ftrace_lookup_ip(other_hash
, rec
->ip
))
1381 in_hash
= hash
&& !!ftrace_lookup_ip(hash
, rec
->ip
);
1382 in_other_hash
= other_hash
&& !!ftrace_lookup_ip(other_hash
, rec
->ip
);
1387 if (filter_hash
&& in_hash
&& !in_other_hash
)
1389 else if (!filter_hash
&& in_hash
&&
1390 (in_other_hash
|| !other_hash
->count
))
1398 if (FTRACE_WARN_ON((rec
->flags
& ~FTRACE_FL_MASK
) == FTRACE_REF_MAX
))
1401 if (FTRACE_WARN_ON((rec
->flags
& ~FTRACE_FL_MASK
) == 0))
1406 /* Shortcut, if we handled all records, we are done. */
1407 if (!all
&& count
== hash
->count
)
1409 } while_for_each_ftrace_rec();
1412 static void ftrace_hash_rec_disable(struct ftrace_ops
*ops
,
1415 __ftrace_hash_rec_update(ops
, filter_hash
, 0);
1418 static void ftrace_hash_rec_enable(struct ftrace_ops
*ops
,
1421 __ftrace_hash_rec_update(ops
, filter_hash
, 1);
1424 static void ftrace_free_rec(struct dyn_ftrace
*rec
)
1426 rec
->freelist
= ftrace_free_records
;
1427 ftrace_free_records
= rec
;
1428 rec
->flags
|= FTRACE_FL_FREE
;
1431 static struct dyn_ftrace
*ftrace_alloc_dyn_node(unsigned long ip
)
1433 struct dyn_ftrace
*rec
;
1435 /* First check for freed records */
1436 if (ftrace_free_records
) {
1437 rec
= ftrace_free_records
;
1439 if (unlikely(!(rec
->flags
& FTRACE_FL_FREE
))) {
1440 FTRACE_WARN_ON_ONCE(1);
1441 ftrace_free_records
= NULL
;
1445 ftrace_free_records
= rec
->freelist
;
1446 memset(rec
, 0, sizeof(*rec
));
1450 if (ftrace_pages
->index
== ENTRIES_PER_PAGE
) {
1451 if (!ftrace_pages
->next
) {
1452 /* allocate another page */
1453 ftrace_pages
->next
=
1454 (void *)get_zeroed_page(GFP_KERNEL
);
1455 if (!ftrace_pages
->next
)
1458 ftrace_pages
= ftrace_pages
->next
;
1461 return &ftrace_pages
->records
[ftrace_pages
->index
++];
1464 static struct dyn_ftrace
*
1465 ftrace_record_ip(unsigned long ip
)
1467 struct dyn_ftrace
*rec
;
1469 if (ftrace_disabled
)
1472 rec
= ftrace_alloc_dyn_node(ip
);
1477 rec
->newlist
= ftrace_new_addrs
;
1478 ftrace_new_addrs
= rec
;
1483 static void print_ip_ins(const char *fmt
, unsigned char *p
)
1487 printk(KERN_CONT
"%s", fmt
);
1489 for (i
= 0; i
< MCOUNT_INSN_SIZE
; i
++)
1490 printk(KERN_CONT
"%s%02x", i
? ":" : "", p
[i
]);
1494 * ftrace_bug - report and shutdown function tracer
1495 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1496 * @ip: The address that failed
1498 * The arch code that enables or disables the function tracing
1499 * can call ftrace_bug() when it has detected a problem in
1500 * modifying the code. @failed should be one of either:
1501 * EFAULT - if the problem happens on reading the @ip address
1502 * EINVAL - if what is read at @ip is not what was expected
1503 * EPERM - if the problem happens on writting to the @ip address
1505 void ftrace_bug(int failed
, unsigned long ip
)
1509 FTRACE_WARN_ON_ONCE(1);
1510 pr_info("ftrace faulted on modifying ");
1514 FTRACE_WARN_ON_ONCE(1);
1515 pr_info("ftrace failed to modify ");
1517 print_ip_ins(" actual: ", (unsigned char *)ip
);
1518 printk(KERN_CONT
"\n");
1521 FTRACE_WARN_ON_ONCE(1);
1522 pr_info("ftrace faulted on writing ");
1526 FTRACE_WARN_ON_ONCE(1);
1527 pr_info("ftrace faulted on unknown error ");
1533 /* Return 1 if the address range is reserved for ftrace */
1534 int ftrace_text_reserved(void *start
, void *end
)
1536 struct dyn_ftrace
*rec
;
1537 struct ftrace_page
*pg
;
1539 do_for_each_ftrace_rec(pg
, rec
) {
1540 if (rec
->ip
<= (unsigned long)end
&&
1541 rec
->ip
+ MCOUNT_INSN_SIZE
> (unsigned long)start
)
1543 } while_for_each_ftrace_rec();
1547 static int ftrace_check_record(struct dyn_ftrace
*rec
, int enable
, int update
)
1549 unsigned long flag
= 0UL;
1552 * If we are updating calls:
1554 * If the record has a ref count, then we need to enable it
1555 * because someone is using it.
1557 * Otherwise we make sure its disabled.
1559 * If we are disabling calls, then disable all records that
1562 if (enable
&& (rec
->flags
& ~FTRACE_FL_MASK
))
1563 flag
= FTRACE_FL_ENABLED
;
1565 /* If the state of this record hasn't changed, then do nothing */
1566 if ((rec
->flags
& FTRACE_FL_ENABLED
) == flag
)
1567 return FTRACE_UPDATE_IGNORE
;
1571 rec
->flags
|= FTRACE_FL_ENABLED
;
1572 return FTRACE_UPDATE_MAKE_CALL
;
1576 rec
->flags
&= ~FTRACE_FL_ENABLED
;
1578 return FTRACE_UPDATE_MAKE_NOP
;
1582 * ftrace_update_record, set a record that now is tracing or not
1583 * @rec: the record to update
1584 * @enable: set to 1 if the record is tracing, zero to force disable
1586 * The records that represent all functions that can be traced need
1587 * to be updated when tracing has been enabled.
1589 int ftrace_update_record(struct dyn_ftrace
*rec
, int enable
)
1591 return ftrace_check_record(rec
, enable
, 1);
1595 * ftrace_test_record, check if the record has been enabled or not
1596 * @rec: the record to test
1597 * @enable: set to 1 to check if enabled, 0 if it is disabled
1599 * The arch code may need to test if a record is already set to
1600 * tracing to determine how to modify the function code that it
1603 int ftrace_test_record(struct dyn_ftrace
*rec
, int enable
)
1605 return ftrace_check_record(rec
, enable
, 0);
1609 __ftrace_replace_code(struct dyn_ftrace
*rec
, int enable
)
1611 unsigned long ftrace_addr
;
1614 ftrace_addr
= (unsigned long)FTRACE_ADDR
;
1616 ret
= ftrace_update_record(rec
, enable
);
1619 case FTRACE_UPDATE_IGNORE
:
1622 case FTRACE_UPDATE_MAKE_CALL
:
1623 return ftrace_make_call(rec
, ftrace_addr
);
1625 case FTRACE_UPDATE_MAKE_NOP
:
1626 return ftrace_make_nop(NULL
, rec
, ftrace_addr
);
1629 return -1; /* unknow ftrace bug */
1632 static void ftrace_replace_code(int update
)
1634 struct dyn_ftrace
*rec
;
1635 struct ftrace_page
*pg
;
1638 if (unlikely(ftrace_disabled
))
1641 do_for_each_ftrace_rec(pg
, rec
) {
1642 /* Skip over free records */
1643 if (rec
->flags
& FTRACE_FL_FREE
)
1646 failed
= __ftrace_replace_code(rec
, update
);
1648 ftrace_bug(failed
, rec
->ip
);
1649 /* Stop processing */
1652 } while_for_each_ftrace_rec();
1655 struct ftrace_rec_iter
{
1656 struct ftrace_page
*pg
;
1661 * ftrace_rec_iter_start, start up iterating over traced functions
1663 * Returns an iterator handle that is used to iterate over all
1664 * the records that represent address locations where functions
1667 * May return NULL if no records are available.
1669 struct ftrace_rec_iter
*ftrace_rec_iter_start(void)
1672 * We only use a single iterator.
1673 * Protected by the ftrace_lock mutex.
1675 static struct ftrace_rec_iter ftrace_rec_iter
;
1676 struct ftrace_rec_iter
*iter
= &ftrace_rec_iter
;
1678 iter
->pg
= ftrace_pages_start
;
1681 /* Could have empty pages */
1682 while (iter
->pg
&& !iter
->pg
->index
)
1683 iter
->pg
= iter
->pg
->next
;
1692 * ftrace_rec_iter_next, get the next record to process.
1693 * @iter: The handle to the iterator.
1695 * Returns the next iterator after the given iterator @iter.
1697 struct ftrace_rec_iter
*ftrace_rec_iter_next(struct ftrace_rec_iter
*iter
)
1701 if (iter
->index
>= iter
->pg
->index
) {
1702 iter
->pg
= iter
->pg
->next
;
1705 /* Could have empty pages */
1706 while (iter
->pg
&& !iter
->pg
->index
)
1707 iter
->pg
= iter
->pg
->next
;
1717 * ftrace_rec_iter_record, get the record at the iterator location
1718 * @iter: The current iterator location
1720 * Returns the record that the current @iter is at.
1722 struct dyn_ftrace
*ftrace_rec_iter_record(struct ftrace_rec_iter
*iter
)
1724 return &iter
->pg
->records
[iter
->index
];
1728 ftrace_code_disable(struct module
*mod
, struct dyn_ftrace
*rec
)
1735 if (unlikely(ftrace_disabled
))
1738 ret
= ftrace_make_nop(mod
, rec
, MCOUNT_ADDR
);
1740 ftrace_bug(ret
, ip
);
1747 * archs can override this function if they must do something
1748 * before the modifying code is performed.
1750 int __weak
ftrace_arch_code_modify_prepare(void)
1756 * archs can override this function if they must do something
1757 * after the modifying code is performed.
1759 int __weak
ftrace_arch_code_modify_post_process(void)
1764 static int __ftrace_modify_code(void *data
)
1766 int *command
= data
;
1768 if (*command
& FTRACE_UPDATE_CALLS
)
1769 ftrace_replace_code(1);
1770 else if (*command
& FTRACE_DISABLE_CALLS
)
1771 ftrace_replace_code(0);
1773 if (*command
& FTRACE_UPDATE_TRACE_FUNC
)
1774 ftrace_update_ftrace_func(ftrace_trace_function
);
1776 if (*command
& FTRACE_START_FUNC_RET
)
1777 ftrace_enable_ftrace_graph_caller();
1778 else if (*command
& FTRACE_STOP_FUNC_RET
)
1779 ftrace_disable_ftrace_graph_caller();
1785 * ftrace_run_stop_machine, go back to the stop machine method
1786 * @command: The command to tell ftrace what to do
1788 * If an arch needs to fall back to the stop machine method, the
1789 * it can call this function.
1791 void ftrace_run_stop_machine(int command
)
1793 stop_machine(__ftrace_modify_code
, &command
, NULL
);
1797 * arch_ftrace_update_code, modify the code to trace or not trace
1798 * @command: The command that needs to be done
1800 * Archs can override this function if it does not need to
1801 * run stop_machine() to modify code.
1803 void __weak
arch_ftrace_update_code(int command
)
1805 ftrace_run_stop_machine(command
);
1808 static void ftrace_run_update_code(int command
)
1812 ret
= ftrace_arch_code_modify_prepare();
1813 FTRACE_WARN_ON(ret
);
1817 * Do not call function tracer while we update the code.
1818 * We are in stop machine.
1820 function_trace_stop
++;
1823 * By default we use stop_machine() to modify the code.
1824 * But archs can do what ever they want as long as it
1825 * is safe. The stop_machine() is the safest, but also
1826 * produces the most overhead.
1828 arch_ftrace_update_code(command
);
1830 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
1832 * For archs that call ftrace_test_stop_func(), we must
1833 * wait till after we update all the function callers
1834 * before we update the callback. This keeps different
1835 * ops that record different functions from corrupting
1838 __ftrace_trace_function
= __ftrace_trace_function_delay
;
1840 function_trace_stop
--;
1842 ret
= ftrace_arch_code_modify_post_process();
1843 FTRACE_WARN_ON(ret
);
1846 static ftrace_func_t saved_ftrace_func
;
1847 static int ftrace_start_up
;
1848 static int global_start_up
;
1850 static void ftrace_startup_enable(int command
)
1852 if (saved_ftrace_func
!= ftrace_trace_function
) {
1853 saved_ftrace_func
= ftrace_trace_function
;
1854 command
|= FTRACE_UPDATE_TRACE_FUNC
;
1857 if (!command
|| !ftrace_enabled
)
1860 ftrace_run_update_code(command
);
1863 static int ftrace_startup(struct ftrace_ops
*ops
, int command
)
1865 bool hash_enable
= true;
1867 if (unlikely(ftrace_disabled
))
1871 command
|= FTRACE_UPDATE_CALLS
;
1873 /* ops marked global share the filter hashes */
1874 if (ops
->flags
& FTRACE_OPS_FL_GLOBAL
) {
1876 /* Don't update hash if global is already set */
1877 if (global_start_up
)
1878 hash_enable
= false;
1882 ops
->flags
|= FTRACE_OPS_FL_ENABLED
;
1884 ftrace_hash_rec_enable(ops
, 1);
1886 ftrace_startup_enable(command
);
1891 static void ftrace_shutdown(struct ftrace_ops
*ops
, int command
)
1893 bool hash_disable
= true;
1895 if (unlikely(ftrace_disabled
))
1900 * Just warn in case of unbalance, no need to kill ftrace, it's not
1901 * critical but the ftrace_call callers may be never nopped again after
1902 * further ftrace uses.
1904 WARN_ON_ONCE(ftrace_start_up
< 0);
1906 if (ops
->flags
& FTRACE_OPS_FL_GLOBAL
) {
1909 WARN_ON_ONCE(global_start_up
< 0);
1910 /* Don't update hash if global still has users */
1911 if (global_start_up
) {
1912 WARN_ON_ONCE(!ftrace_start_up
);
1913 hash_disable
= false;
1918 ftrace_hash_rec_disable(ops
, 1);
1920 if (ops
!= &global_ops
|| !global_start_up
)
1921 ops
->flags
&= ~FTRACE_OPS_FL_ENABLED
;
1923 command
|= FTRACE_UPDATE_CALLS
;
1925 if (saved_ftrace_func
!= ftrace_trace_function
) {
1926 saved_ftrace_func
= ftrace_trace_function
;
1927 command
|= FTRACE_UPDATE_TRACE_FUNC
;
1930 if (!command
|| !ftrace_enabled
)
1933 ftrace_run_update_code(command
);
1936 static void ftrace_startup_sysctl(void)
1938 if (unlikely(ftrace_disabled
))
1941 /* Force update next time */
1942 saved_ftrace_func
= NULL
;
1943 /* ftrace_start_up is true if we want ftrace running */
1944 if (ftrace_start_up
)
1945 ftrace_run_update_code(FTRACE_UPDATE_CALLS
);
1948 static void ftrace_shutdown_sysctl(void)
1950 if (unlikely(ftrace_disabled
))
1953 /* ftrace_start_up is true if ftrace is running */
1954 if (ftrace_start_up
)
1955 ftrace_run_update_code(FTRACE_DISABLE_CALLS
);
1958 static cycle_t ftrace_update_time
;
1959 static unsigned long ftrace_update_cnt
;
1960 unsigned long ftrace_update_tot_cnt
;
1962 static int ops_traces_mod(struct ftrace_ops
*ops
)
1964 struct ftrace_hash
*hash
;
1966 hash
= ops
->filter_hash
;
1967 return !!(!hash
|| !hash
->count
);
1970 static int ftrace_update_code(struct module
*mod
)
1972 struct dyn_ftrace
*p
;
1973 cycle_t start
, stop
;
1974 unsigned long ref
= 0;
1977 * When adding a module, we need to check if tracers are
1978 * currently enabled and if they are set to trace all functions.
1979 * If they are, we need to enable the module functions as well
1980 * as update the reference counts for those function records.
1983 struct ftrace_ops
*ops
;
1985 for (ops
= ftrace_ops_list
;
1986 ops
!= &ftrace_list_end
; ops
= ops
->next
) {
1987 if (ops
->flags
& FTRACE_OPS_FL_ENABLED
&&
1988 ops_traces_mod(ops
))
1993 start
= ftrace_now(raw_smp_processor_id());
1994 ftrace_update_cnt
= 0;
1996 while (ftrace_new_addrs
) {
1998 /* If something went wrong, bail without enabling anything */
1999 if (unlikely(ftrace_disabled
))
2002 p
= ftrace_new_addrs
;
2003 ftrace_new_addrs
= p
->newlist
;
2007 * Do the initial record conversion from mcount jump
2008 * to the NOP instructions.
2010 if (!ftrace_code_disable(mod
, p
)) {
2016 ftrace_update_cnt
++;
2019 * If the tracing is enabled, go ahead and enable the record.
2021 * The reason not to enable the record immediatelly is the
2022 * inherent check of ftrace_make_nop/ftrace_make_call for
2023 * correct previous instructions. Making first the NOP
2024 * conversion puts the module to the correct state, thus
2025 * passing the ftrace_make_call check.
2027 if (ftrace_start_up
&& ref
) {
2028 int failed
= __ftrace_replace_code(p
, 1);
2030 ftrace_bug(failed
, p
->ip
);
2036 stop
= ftrace_now(raw_smp_processor_id());
2037 ftrace_update_time
= stop
- start
;
2038 ftrace_update_tot_cnt
+= ftrace_update_cnt
;
2043 static int __init
ftrace_dyn_table_alloc(unsigned long num_to_init
)
2045 struct ftrace_page
*pg
;
2049 /* allocate a few pages */
2050 ftrace_pages_start
= (void *)get_zeroed_page(GFP_KERNEL
);
2051 if (!ftrace_pages_start
)
2055 * Allocate a few more pages.
2057 * TODO: have some parser search vmlinux before
2058 * final linking to find all calls to ftrace.
2060 * a) know how many pages to allocate.
2062 * b) set up the table then.
2064 * The dynamic code is still necessary for
2068 pg
= ftrace_pages
= ftrace_pages_start
;
2070 cnt
= num_to_init
/ ENTRIES_PER_PAGE
;
2071 pr_info("ftrace: allocating %ld entries in %d pages\n",
2072 num_to_init
, cnt
+ 1);
2074 for (i
= 0; i
< cnt
; i
++) {
2075 pg
->next
= (void *)get_zeroed_page(GFP_KERNEL
);
2077 /* If we fail, we'll try later anyway */
2088 FTRACE_ITER_FILTER
= (1 << 0),
2089 FTRACE_ITER_NOTRACE
= (1 << 1),
2090 FTRACE_ITER_PRINTALL
= (1 << 2),
2091 FTRACE_ITER_HASH
= (1 << 3),
2092 FTRACE_ITER_ENABLED
= (1 << 4),
2095 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
2097 struct ftrace_iterator
{
2100 struct ftrace_page
*pg
;
2101 struct dyn_ftrace
*func
;
2102 struct ftrace_func_probe
*probe
;
2103 struct trace_parser parser
;
2104 struct ftrace_hash
*hash
;
2105 struct ftrace_ops
*ops
;
2112 t_hash_next(struct seq_file
*m
, loff_t
*pos
)
2114 struct ftrace_iterator
*iter
= m
->private;
2115 struct hlist_node
*hnd
= NULL
;
2116 struct hlist_head
*hhd
;
2122 hnd
= &iter
->probe
->node
;
2124 if (iter
->hidx
>= FTRACE_FUNC_HASHSIZE
)
2127 hhd
= &ftrace_func_hash
[iter
->hidx
];
2129 if (hlist_empty(hhd
)) {
2145 if (WARN_ON_ONCE(!hnd
))
2148 iter
->probe
= hlist_entry(hnd
, struct ftrace_func_probe
, node
);
2153 static void *t_hash_start(struct seq_file
*m
, loff_t
*pos
)
2155 struct ftrace_iterator
*iter
= m
->private;
2159 if (iter
->func_pos
> *pos
)
2163 for (l
= 0; l
<= (*pos
- iter
->func_pos
); ) {
2164 p
= t_hash_next(m
, &l
);
2171 /* Only set this if we have an item */
2172 iter
->flags
|= FTRACE_ITER_HASH
;
2178 t_hash_show(struct seq_file
*m
, struct ftrace_iterator
*iter
)
2180 struct ftrace_func_probe
*rec
;
2183 if (WARN_ON_ONCE(!rec
))
2186 if (rec
->ops
->print
)
2187 return rec
->ops
->print(m
, rec
->ip
, rec
->ops
, rec
->data
);
2189 seq_printf(m
, "%ps:%ps", (void *)rec
->ip
, (void *)rec
->ops
->func
);
2192 seq_printf(m
, ":%p", rec
->data
);
2199 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
2201 struct ftrace_iterator
*iter
= m
->private;
2202 struct ftrace_ops
*ops
= &global_ops
;
2203 struct dyn_ftrace
*rec
= NULL
;
2205 if (unlikely(ftrace_disabled
))
2208 if (iter
->flags
& FTRACE_ITER_HASH
)
2209 return t_hash_next(m
, pos
);
2212 iter
->pos
= iter
->func_pos
= *pos
;
2214 if (iter
->flags
& FTRACE_ITER_PRINTALL
)
2215 return t_hash_start(m
, pos
);
2218 if (iter
->idx
>= iter
->pg
->index
) {
2219 if (iter
->pg
->next
) {
2220 iter
->pg
= iter
->pg
->next
;
2225 rec
= &iter
->pg
->records
[iter
->idx
++];
2226 if ((rec
->flags
& FTRACE_FL_FREE
) ||
2228 ((iter
->flags
& FTRACE_ITER_FILTER
) &&
2229 !(ftrace_lookup_ip(ops
->filter_hash
, rec
->ip
))) ||
2231 ((iter
->flags
& FTRACE_ITER_NOTRACE
) &&
2232 !ftrace_lookup_ip(ops
->notrace_hash
, rec
->ip
)) ||
2234 ((iter
->flags
& FTRACE_ITER_ENABLED
) &&
2235 !(rec
->flags
& ~FTRACE_FL_MASK
))) {
2243 return t_hash_start(m
, pos
);
2250 static void reset_iter_read(struct ftrace_iterator
*iter
)
2254 iter
->flags
&= ~(FTRACE_ITER_PRINTALL
& FTRACE_ITER_HASH
);
2257 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
2259 struct ftrace_iterator
*iter
= m
->private;
2260 struct ftrace_ops
*ops
= &global_ops
;
2264 mutex_lock(&ftrace_lock
);
2266 if (unlikely(ftrace_disabled
))
2270 * If an lseek was done, then reset and start from beginning.
2272 if (*pos
< iter
->pos
)
2273 reset_iter_read(iter
);
2276 * For set_ftrace_filter reading, if we have the filter
2277 * off, we can short cut and just print out that all
2278 * functions are enabled.
2280 if (iter
->flags
& FTRACE_ITER_FILTER
&& !ops
->filter_hash
->count
) {
2282 return t_hash_start(m
, pos
);
2283 iter
->flags
|= FTRACE_ITER_PRINTALL
;
2284 /* reset in case of seek/pread */
2285 iter
->flags
&= ~FTRACE_ITER_HASH
;
2289 if (iter
->flags
& FTRACE_ITER_HASH
)
2290 return t_hash_start(m
, pos
);
2293 * Unfortunately, we need to restart at ftrace_pages_start
2294 * every time we let go of the ftrace_mutex. This is because
2295 * those pointers can change without the lock.
2297 iter
->pg
= ftrace_pages_start
;
2299 for (l
= 0; l
<= *pos
; ) {
2300 p
= t_next(m
, p
, &l
);
2306 if (iter
->flags
& FTRACE_ITER_FILTER
)
2307 return t_hash_start(m
, pos
);
2315 static void t_stop(struct seq_file
*m
, void *p
)
2317 mutex_unlock(&ftrace_lock
);
2320 static int t_show(struct seq_file
*m
, void *v
)
2322 struct ftrace_iterator
*iter
= m
->private;
2323 struct dyn_ftrace
*rec
;
2325 if (iter
->flags
& FTRACE_ITER_HASH
)
2326 return t_hash_show(m
, iter
);
2328 if (iter
->flags
& FTRACE_ITER_PRINTALL
) {
2329 seq_printf(m
, "#### all functions enabled ####\n");
2338 seq_printf(m
, "%ps", (void *)rec
->ip
);
2339 if (iter
->flags
& FTRACE_ITER_ENABLED
)
2340 seq_printf(m
, " (%ld)",
2341 rec
->flags
& ~FTRACE_FL_MASK
);
2342 seq_printf(m
, "\n");
2347 static const struct seq_operations show_ftrace_seq_ops
= {
2355 ftrace_avail_open(struct inode
*inode
, struct file
*file
)
2357 struct ftrace_iterator
*iter
;
2360 if (unlikely(ftrace_disabled
))
2363 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2367 iter
->pg
= ftrace_pages_start
;
2369 ret
= seq_open(file
, &show_ftrace_seq_ops
);
2371 struct seq_file
*m
= file
->private_data
;
2382 ftrace_enabled_open(struct inode
*inode
, struct file
*file
)
2384 struct ftrace_iterator
*iter
;
2387 if (unlikely(ftrace_disabled
))
2390 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2394 iter
->pg
= ftrace_pages_start
;
2395 iter
->flags
= FTRACE_ITER_ENABLED
;
2397 ret
= seq_open(file
, &show_ftrace_seq_ops
);
2399 struct seq_file
*m
= file
->private_data
;
2409 static void ftrace_filter_reset(struct ftrace_hash
*hash
)
2411 mutex_lock(&ftrace_lock
);
2412 ftrace_hash_clear(hash
);
2413 mutex_unlock(&ftrace_lock
);
2417 ftrace_regex_open(struct ftrace_ops
*ops
, int flag
,
2418 struct inode
*inode
, struct file
*file
)
2420 struct ftrace_iterator
*iter
;
2421 struct ftrace_hash
*hash
;
2424 if (unlikely(ftrace_disabled
))
2427 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2431 if (trace_parser_get_init(&iter
->parser
, FTRACE_BUFF_MAX
)) {
2436 if (flag
& FTRACE_ITER_NOTRACE
)
2437 hash
= ops
->notrace_hash
;
2439 hash
= ops
->filter_hash
;
2444 if (file
->f_mode
& FMODE_WRITE
) {
2445 mutex_lock(&ftrace_lock
);
2446 iter
->hash
= alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
, hash
);
2447 mutex_unlock(&ftrace_lock
);
2450 trace_parser_put(&iter
->parser
);
2456 mutex_lock(&ftrace_regex_lock
);
2458 if ((file
->f_mode
& FMODE_WRITE
) &&
2459 (file
->f_flags
& O_TRUNC
))
2460 ftrace_filter_reset(iter
->hash
);
2462 if (file
->f_mode
& FMODE_READ
) {
2463 iter
->pg
= ftrace_pages_start
;
2465 ret
= seq_open(file
, &show_ftrace_seq_ops
);
2467 struct seq_file
*m
= file
->private_data
;
2471 free_ftrace_hash(iter
->hash
);
2472 trace_parser_put(&iter
->parser
);
2476 file
->private_data
= iter
;
2477 mutex_unlock(&ftrace_regex_lock
);
2483 ftrace_filter_open(struct inode
*inode
, struct file
*file
)
2485 return ftrace_regex_open(&global_ops
, FTRACE_ITER_FILTER
,
2490 ftrace_notrace_open(struct inode
*inode
, struct file
*file
)
2492 return ftrace_regex_open(&global_ops
, FTRACE_ITER_NOTRACE
,
2497 ftrace_regex_lseek(struct file
*file
, loff_t offset
, int origin
)
2501 if (file
->f_mode
& FMODE_READ
)
2502 ret
= seq_lseek(file
, offset
, origin
);
2504 file
->f_pos
= ret
= 1;
2509 static int ftrace_match(char *str
, char *regex
, int len
, int type
)
2516 if (strcmp(str
, regex
) == 0)
2519 case MATCH_FRONT_ONLY
:
2520 if (strncmp(str
, regex
, len
) == 0)
2523 case MATCH_MIDDLE_ONLY
:
2524 if (strstr(str
, regex
))
2527 case MATCH_END_ONLY
:
2529 if (slen
>= len
&& memcmp(str
+ slen
- len
, regex
, len
) == 0)
2538 enter_record(struct ftrace_hash
*hash
, struct dyn_ftrace
*rec
, int not)
2540 struct ftrace_func_entry
*entry
;
2543 entry
= ftrace_lookup_ip(hash
, rec
->ip
);
2545 /* Do nothing if it doesn't exist */
2549 free_hash_entry(hash
, entry
);
2551 /* Do nothing if it exists */
2555 ret
= add_hash_entry(hash
, rec
->ip
);
2561 ftrace_match_record(struct dyn_ftrace
*rec
, char *mod
,
2562 char *regex
, int len
, int type
)
2564 char str
[KSYM_SYMBOL_LEN
];
2567 kallsyms_lookup(rec
->ip
, NULL
, NULL
, &modname
, str
);
2570 /* module lookup requires matching the module */
2571 if (!modname
|| strcmp(modname
, mod
))
2574 /* blank search means to match all funcs in the mod */
2579 return ftrace_match(str
, regex
, len
, type
);
2583 match_records(struct ftrace_hash
*hash
, char *buff
,
2584 int len
, char *mod
, int not)
2586 unsigned search_len
= 0;
2587 struct ftrace_page
*pg
;
2588 struct dyn_ftrace
*rec
;
2589 int type
= MATCH_FULL
;
2590 char *search
= buff
;
2595 type
= filter_parse_regex(buff
, len
, &search
, ¬);
2596 search_len
= strlen(search
);
2599 mutex_lock(&ftrace_lock
);
2601 if (unlikely(ftrace_disabled
))
2604 do_for_each_ftrace_rec(pg
, rec
) {
2606 if (ftrace_match_record(rec
, mod
, search
, search_len
, type
)) {
2607 ret
= enter_record(hash
, rec
, not);
2614 } while_for_each_ftrace_rec();
2616 mutex_unlock(&ftrace_lock
);
2622 ftrace_match_records(struct ftrace_hash
*hash
, char *buff
, int len
)
2624 return match_records(hash
, buff
, len
, NULL
, 0);
2628 ftrace_match_module_records(struct ftrace_hash
*hash
, char *buff
, char *mod
)
2632 /* blank or '*' mean the same */
2633 if (strcmp(buff
, "*") == 0)
2636 /* handle the case of 'dont filter this module' */
2637 if (strcmp(buff
, "!") == 0 || strcmp(buff
, "!*") == 0) {
2642 return match_records(hash
, buff
, strlen(buff
), mod
, not);
2646 * We register the module command as a template to show others how
2647 * to register the a command as well.
2651 ftrace_mod_callback(struct ftrace_hash
*hash
,
2652 char *func
, char *cmd
, char *param
, int enable
)
2658 * cmd == 'mod' because we only registered this func
2659 * for the 'mod' ftrace_func_command.
2660 * But if you register one func with multiple commands,
2661 * you can tell which command was used by the cmd
2665 /* we must have a module name */
2669 mod
= strsep(¶m
, ":");
2673 ret
= ftrace_match_module_records(hash
, func
, mod
);
2682 static struct ftrace_func_command ftrace_mod_cmd
= {
2684 .func
= ftrace_mod_callback
,
2687 static int __init
ftrace_mod_cmd_init(void)
2689 return register_ftrace_command(&ftrace_mod_cmd
);
2691 device_initcall(ftrace_mod_cmd_init
);
2694 function_trace_probe_call(unsigned long ip
, unsigned long parent_ip
)
2696 struct ftrace_func_probe
*entry
;
2697 struct hlist_head
*hhd
;
2698 struct hlist_node
*n
;
2701 key
= hash_long(ip
, FTRACE_HASH_BITS
);
2703 hhd
= &ftrace_func_hash
[key
];
2705 if (hlist_empty(hhd
))
2709 * Disable preemption for these calls to prevent a RCU grace
2710 * period. This syncs the hash iteration and freeing of items
2711 * on the hash. rcu_read_lock is too dangerous here.
2713 preempt_disable_notrace();
2714 hlist_for_each_entry_rcu(entry
, n
, hhd
, node
) {
2715 if (entry
->ip
== ip
)
2716 entry
->ops
->func(ip
, parent_ip
, &entry
->data
);
2718 preempt_enable_notrace();
2721 static struct ftrace_ops trace_probe_ops __read_mostly
=
2723 .func
= function_trace_probe_call
,
2726 static int ftrace_probe_registered
;
2728 static void __enable_ftrace_function_probe(void)
2733 if (ftrace_probe_registered
)
2736 for (i
= 0; i
< FTRACE_FUNC_HASHSIZE
; i
++) {
2737 struct hlist_head
*hhd
= &ftrace_func_hash
[i
];
2741 /* Nothing registered? */
2742 if (i
== FTRACE_FUNC_HASHSIZE
)
2745 ret
= __register_ftrace_function(&trace_probe_ops
);
2747 ret
= ftrace_startup(&trace_probe_ops
, 0);
2749 ftrace_probe_registered
= 1;
2752 static void __disable_ftrace_function_probe(void)
2757 if (!ftrace_probe_registered
)
2760 for (i
= 0; i
< FTRACE_FUNC_HASHSIZE
; i
++) {
2761 struct hlist_head
*hhd
= &ftrace_func_hash
[i
];
2766 /* no more funcs left */
2767 ret
= __unregister_ftrace_function(&trace_probe_ops
);
2769 ftrace_shutdown(&trace_probe_ops
, 0);
2771 ftrace_probe_registered
= 0;
2775 static void ftrace_free_entry_rcu(struct rcu_head
*rhp
)
2777 struct ftrace_func_probe
*entry
=
2778 container_of(rhp
, struct ftrace_func_probe
, rcu
);
2780 if (entry
->ops
->free
)
2781 entry
->ops
->free(&entry
->data
);
2787 register_ftrace_function_probe(char *glob
, struct ftrace_probe_ops
*ops
,
2790 struct ftrace_func_probe
*entry
;
2791 struct ftrace_page
*pg
;
2792 struct dyn_ftrace
*rec
;
2798 type
= filter_parse_regex(glob
, strlen(glob
), &search
, ¬);
2799 len
= strlen(search
);
2801 /* we do not support '!' for function probes */
2805 mutex_lock(&ftrace_lock
);
2807 if (unlikely(ftrace_disabled
))
2810 do_for_each_ftrace_rec(pg
, rec
) {
2812 if (!ftrace_match_record(rec
, NULL
, search
, len
, type
))
2815 entry
= kmalloc(sizeof(*entry
), GFP_KERNEL
);
2817 /* If we did not process any, then return error */
2828 * The caller might want to do something special
2829 * for each function we find. We call the callback
2830 * to give the caller an opportunity to do so.
2832 if (ops
->callback
) {
2833 if (ops
->callback(rec
->ip
, &entry
->data
) < 0) {
2834 /* caller does not like this func */
2841 entry
->ip
= rec
->ip
;
2843 key
= hash_long(entry
->ip
, FTRACE_HASH_BITS
);
2844 hlist_add_head_rcu(&entry
->node
, &ftrace_func_hash
[key
]);
2846 } while_for_each_ftrace_rec();
2847 __enable_ftrace_function_probe();
2850 mutex_unlock(&ftrace_lock
);
2856 PROBE_TEST_FUNC
= 1,
2861 __unregister_ftrace_function_probe(char *glob
, struct ftrace_probe_ops
*ops
,
2862 void *data
, int flags
)
2864 struct ftrace_func_probe
*entry
;
2865 struct hlist_node
*n
, *tmp
;
2866 char str
[KSYM_SYMBOL_LEN
];
2867 int type
= MATCH_FULL
;
2871 if (glob
&& (strcmp(glob
, "*") == 0 || !strlen(glob
)))
2876 type
= filter_parse_regex(glob
, strlen(glob
), &search
, ¬);
2877 len
= strlen(search
);
2879 /* we do not support '!' for function probes */
2884 mutex_lock(&ftrace_lock
);
2885 for (i
= 0; i
< FTRACE_FUNC_HASHSIZE
; i
++) {
2886 struct hlist_head
*hhd
= &ftrace_func_hash
[i
];
2888 hlist_for_each_entry_safe(entry
, n
, tmp
, hhd
, node
) {
2890 /* break up if statements for readability */
2891 if ((flags
& PROBE_TEST_FUNC
) && entry
->ops
!= ops
)
2894 if ((flags
& PROBE_TEST_DATA
) && entry
->data
!= data
)
2897 /* do this last, since it is the most expensive */
2899 kallsyms_lookup(entry
->ip
, NULL
, NULL
,
2901 if (!ftrace_match(str
, glob
, len
, type
))
2905 hlist_del(&entry
->node
);
2906 call_rcu(&entry
->rcu
, ftrace_free_entry_rcu
);
2909 __disable_ftrace_function_probe();
2910 mutex_unlock(&ftrace_lock
);
2914 unregister_ftrace_function_probe(char *glob
, struct ftrace_probe_ops
*ops
,
2917 __unregister_ftrace_function_probe(glob
, ops
, data
,
2918 PROBE_TEST_FUNC
| PROBE_TEST_DATA
);
2922 unregister_ftrace_function_probe_func(char *glob
, struct ftrace_probe_ops
*ops
)
2924 __unregister_ftrace_function_probe(glob
, ops
, NULL
, PROBE_TEST_FUNC
);
2927 void unregister_ftrace_function_probe_all(char *glob
)
2929 __unregister_ftrace_function_probe(glob
, NULL
, NULL
, 0);
2932 static LIST_HEAD(ftrace_commands
);
2933 static DEFINE_MUTEX(ftrace_cmd_mutex
);
2935 int register_ftrace_command(struct ftrace_func_command
*cmd
)
2937 struct ftrace_func_command
*p
;
2940 mutex_lock(&ftrace_cmd_mutex
);
2941 list_for_each_entry(p
, &ftrace_commands
, list
) {
2942 if (strcmp(cmd
->name
, p
->name
) == 0) {
2947 list_add(&cmd
->list
, &ftrace_commands
);
2949 mutex_unlock(&ftrace_cmd_mutex
);
2954 int unregister_ftrace_command(struct ftrace_func_command
*cmd
)
2956 struct ftrace_func_command
*p
, *n
;
2959 mutex_lock(&ftrace_cmd_mutex
);
2960 list_for_each_entry_safe(p
, n
, &ftrace_commands
, list
) {
2961 if (strcmp(cmd
->name
, p
->name
) == 0) {
2963 list_del_init(&p
->list
);
2968 mutex_unlock(&ftrace_cmd_mutex
);
2973 static int ftrace_process_regex(struct ftrace_hash
*hash
,
2974 char *buff
, int len
, int enable
)
2976 char *func
, *command
, *next
= buff
;
2977 struct ftrace_func_command
*p
;
2980 func
= strsep(&next
, ":");
2983 ret
= ftrace_match_records(hash
, func
, len
);
2993 command
= strsep(&next
, ":");
2995 mutex_lock(&ftrace_cmd_mutex
);
2996 list_for_each_entry(p
, &ftrace_commands
, list
) {
2997 if (strcmp(p
->name
, command
) == 0) {
2998 ret
= p
->func(hash
, func
, command
, next
, enable
);
3003 mutex_unlock(&ftrace_cmd_mutex
);
3009 ftrace_regex_write(struct file
*file
, const char __user
*ubuf
,
3010 size_t cnt
, loff_t
*ppos
, int enable
)
3012 struct ftrace_iterator
*iter
;
3013 struct trace_parser
*parser
;
3019 mutex_lock(&ftrace_regex_lock
);
3022 if (unlikely(ftrace_disabled
))
3025 if (file
->f_mode
& FMODE_READ
) {
3026 struct seq_file
*m
= file
->private_data
;
3029 iter
= file
->private_data
;
3031 parser
= &iter
->parser
;
3032 read
= trace_get_user(parser
, ubuf
, cnt
, ppos
);
3034 if (read
>= 0 && trace_parser_loaded(parser
) &&
3035 !trace_parser_cont(parser
)) {
3036 ret
= ftrace_process_regex(iter
->hash
, parser
->buffer
,
3037 parser
->idx
, enable
);
3038 trace_parser_clear(parser
);
3045 mutex_unlock(&ftrace_regex_lock
);
3051 ftrace_filter_write(struct file
*file
, const char __user
*ubuf
,
3052 size_t cnt
, loff_t
*ppos
)
3054 return ftrace_regex_write(file
, ubuf
, cnt
, ppos
, 1);
3058 ftrace_notrace_write(struct file
*file
, const char __user
*ubuf
,
3059 size_t cnt
, loff_t
*ppos
)
3061 return ftrace_regex_write(file
, ubuf
, cnt
, ppos
, 0);
3065 ftrace_set_regex(struct ftrace_ops
*ops
, unsigned char *buf
, int len
,
3066 int reset
, int enable
)
3068 struct ftrace_hash
**orig_hash
;
3069 struct ftrace_hash
*hash
;
3072 /* All global ops uses the global ops filters */
3073 if (ops
->flags
& FTRACE_OPS_FL_GLOBAL
)
3076 if (unlikely(ftrace_disabled
))
3080 orig_hash
= &ops
->filter_hash
;
3082 orig_hash
= &ops
->notrace_hash
;
3084 hash
= alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
, *orig_hash
);
3088 mutex_lock(&ftrace_regex_lock
);
3090 ftrace_filter_reset(hash
);
3092 ftrace_match_records(hash
, buf
, len
);
3094 mutex_lock(&ftrace_lock
);
3095 ret
= ftrace_hash_move(ops
, enable
, orig_hash
, hash
);
3096 if (!ret
&& ops
->flags
& FTRACE_OPS_FL_ENABLED
3098 ftrace_run_update_code(FTRACE_UPDATE_CALLS
);
3100 mutex_unlock(&ftrace_lock
);
3102 mutex_unlock(&ftrace_regex_lock
);
3104 free_ftrace_hash(hash
);
3109 * ftrace_set_filter - set a function to filter on in ftrace
3110 * @ops - the ops to set the filter with
3111 * @buf - the string that holds the function filter text.
3112 * @len - the length of the string.
3113 * @reset - non zero to reset all filters before applying this filter.
3115 * Filters denote which functions should be enabled when tracing is enabled.
3116 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3118 void ftrace_set_filter(struct ftrace_ops
*ops
, unsigned char *buf
,
3121 ftrace_set_regex(ops
, buf
, len
, reset
, 1);
3123 EXPORT_SYMBOL_GPL(ftrace_set_filter
);
3126 * ftrace_set_notrace - set a function to not trace in ftrace
3127 * @ops - the ops to set the notrace filter with
3128 * @buf - the string that holds the function notrace text.
3129 * @len - the length of the string.
3130 * @reset - non zero to reset all filters before applying this filter.
3132 * Notrace Filters denote which functions should not be enabled when tracing
3133 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3136 void ftrace_set_notrace(struct ftrace_ops
*ops
, unsigned char *buf
,
3139 ftrace_set_regex(ops
, buf
, len
, reset
, 0);
3141 EXPORT_SYMBOL_GPL(ftrace_set_notrace
);
3143 * ftrace_set_filter - set a function to filter on in ftrace
3144 * @ops - the ops to set the filter with
3145 * @buf - the string that holds the function filter text.
3146 * @len - the length of the string.
3147 * @reset - non zero to reset all filters before applying this filter.
3149 * Filters denote which functions should be enabled when tracing is enabled.
3150 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3152 void ftrace_set_global_filter(unsigned char *buf
, int len
, int reset
)
3154 ftrace_set_regex(&global_ops
, buf
, len
, reset
, 1);
3156 EXPORT_SYMBOL_GPL(ftrace_set_global_filter
);
3159 * ftrace_set_notrace - set a function to not trace in ftrace
3160 * @ops - the ops to set the notrace filter with
3161 * @buf - the string that holds the function notrace text.
3162 * @len - the length of the string.
3163 * @reset - non zero to reset all filters before applying this filter.
3165 * Notrace Filters denote which functions should not be enabled when tracing
3166 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3169 void ftrace_set_global_notrace(unsigned char *buf
, int len
, int reset
)
3171 ftrace_set_regex(&global_ops
, buf
, len
, reset
, 0);
3173 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace
);
3176 * command line interface to allow users to set filters on boot up.
3178 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
3179 static char ftrace_notrace_buf
[FTRACE_FILTER_SIZE
] __initdata
;
3180 static char ftrace_filter_buf
[FTRACE_FILTER_SIZE
] __initdata
;
3182 static int __init
set_ftrace_notrace(char *str
)
3184 strncpy(ftrace_notrace_buf
, str
, FTRACE_FILTER_SIZE
);
3187 __setup("ftrace_notrace=", set_ftrace_notrace
);
3189 static int __init
set_ftrace_filter(char *str
)
3191 strncpy(ftrace_filter_buf
, str
, FTRACE_FILTER_SIZE
);
3194 __setup("ftrace_filter=", set_ftrace_filter
);
3196 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3197 static char ftrace_graph_buf
[FTRACE_FILTER_SIZE
] __initdata
;
3198 static int ftrace_set_func(unsigned long *array
, int *idx
, char *buffer
);
3200 static int __init
set_graph_function(char *str
)
3202 strlcpy(ftrace_graph_buf
, str
, FTRACE_FILTER_SIZE
);
3205 __setup("ftrace_graph_filter=", set_graph_function
);
3207 static void __init
set_ftrace_early_graph(char *buf
)
3213 func
= strsep(&buf
, ",");
3214 /* we allow only one expression at a time */
3215 ret
= ftrace_set_func(ftrace_graph_funcs
, &ftrace_graph_count
,
3218 printk(KERN_DEBUG
"ftrace: function %s not "
3219 "traceable\n", func
);
3222 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3225 set_ftrace_early_filter(struct ftrace_ops
*ops
, char *buf
, int enable
)
3230 func
= strsep(&buf
, ",");
3231 ftrace_set_regex(ops
, func
, strlen(func
), 0, enable
);
3235 static void __init
set_ftrace_early_filters(void)
3237 if (ftrace_filter_buf
[0])
3238 set_ftrace_early_filter(&global_ops
, ftrace_filter_buf
, 1);
3239 if (ftrace_notrace_buf
[0])
3240 set_ftrace_early_filter(&global_ops
, ftrace_notrace_buf
, 0);
3241 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3242 if (ftrace_graph_buf
[0])
3243 set_ftrace_early_graph(ftrace_graph_buf
);
3244 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3248 ftrace_regex_release(struct inode
*inode
, struct file
*file
)
3250 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
3251 struct ftrace_iterator
*iter
;
3252 struct ftrace_hash
**orig_hash
;
3253 struct trace_parser
*parser
;
3257 mutex_lock(&ftrace_regex_lock
);
3258 if (file
->f_mode
& FMODE_READ
) {
3261 seq_release(inode
, file
);
3263 iter
= file
->private_data
;
3265 parser
= &iter
->parser
;
3266 if (trace_parser_loaded(parser
)) {
3267 parser
->buffer
[parser
->idx
] = 0;
3268 ftrace_match_records(iter
->hash
, parser
->buffer
, parser
->idx
);
3271 trace_parser_put(parser
);
3273 if (file
->f_mode
& FMODE_WRITE
) {
3274 filter_hash
= !!(iter
->flags
& FTRACE_ITER_FILTER
);
3277 orig_hash
= &iter
->ops
->filter_hash
;
3279 orig_hash
= &iter
->ops
->notrace_hash
;
3281 mutex_lock(&ftrace_lock
);
3282 ret
= ftrace_hash_move(iter
->ops
, filter_hash
,
3283 orig_hash
, iter
->hash
);
3284 if (!ret
&& (iter
->ops
->flags
& FTRACE_OPS_FL_ENABLED
)
3286 ftrace_run_update_code(FTRACE_UPDATE_CALLS
);
3288 mutex_unlock(&ftrace_lock
);
3290 free_ftrace_hash(iter
->hash
);
3293 mutex_unlock(&ftrace_regex_lock
);
3297 static const struct file_operations ftrace_avail_fops
= {
3298 .open
= ftrace_avail_open
,
3300 .llseek
= seq_lseek
,
3301 .release
= seq_release_private
,
3304 static const struct file_operations ftrace_enabled_fops
= {
3305 .open
= ftrace_enabled_open
,
3307 .llseek
= seq_lseek
,
3308 .release
= seq_release_private
,
3311 static const struct file_operations ftrace_filter_fops
= {
3312 .open
= ftrace_filter_open
,
3314 .write
= ftrace_filter_write
,
3315 .llseek
= ftrace_regex_lseek
,
3316 .release
= ftrace_regex_release
,
3319 static const struct file_operations ftrace_notrace_fops
= {
3320 .open
= ftrace_notrace_open
,
3322 .write
= ftrace_notrace_write
,
3323 .llseek
= ftrace_regex_lseek
,
3324 .release
= ftrace_regex_release
,
3327 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3329 static DEFINE_MUTEX(graph_lock
);
3331 int ftrace_graph_count
;
3332 int ftrace_graph_filter_enabled
;
3333 unsigned long ftrace_graph_funcs
[FTRACE_GRAPH_MAX_FUNCS
] __read_mostly
;
3336 __g_next(struct seq_file
*m
, loff_t
*pos
)
3338 if (*pos
>= ftrace_graph_count
)
3340 return &ftrace_graph_funcs
[*pos
];
3344 g_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
3347 return __g_next(m
, pos
);
3350 static void *g_start(struct seq_file
*m
, loff_t
*pos
)
3352 mutex_lock(&graph_lock
);
3354 /* Nothing, tell g_show to print all functions are enabled */
3355 if (!ftrace_graph_filter_enabled
&& !*pos
)
3358 return __g_next(m
, pos
);
3361 static void g_stop(struct seq_file
*m
, void *p
)
3363 mutex_unlock(&graph_lock
);
3366 static int g_show(struct seq_file
*m
, void *v
)
3368 unsigned long *ptr
= v
;
3373 if (ptr
== (unsigned long *)1) {
3374 seq_printf(m
, "#### all functions enabled ####\n");
3378 seq_printf(m
, "%ps\n", (void *)*ptr
);
3383 static const struct seq_operations ftrace_graph_seq_ops
= {
3391 ftrace_graph_open(struct inode
*inode
, struct file
*file
)
3395 if (unlikely(ftrace_disabled
))
3398 mutex_lock(&graph_lock
);
3399 if ((file
->f_mode
& FMODE_WRITE
) &&
3400 (file
->f_flags
& O_TRUNC
)) {
3401 ftrace_graph_filter_enabled
= 0;
3402 ftrace_graph_count
= 0;
3403 memset(ftrace_graph_funcs
, 0, sizeof(ftrace_graph_funcs
));
3405 mutex_unlock(&graph_lock
);
3407 if (file
->f_mode
& FMODE_READ
)
3408 ret
= seq_open(file
, &ftrace_graph_seq_ops
);
3414 ftrace_graph_release(struct inode
*inode
, struct file
*file
)
3416 if (file
->f_mode
& FMODE_READ
)
3417 seq_release(inode
, file
);
3422 ftrace_set_func(unsigned long *array
, int *idx
, char *buffer
)
3424 struct dyn_ftrace
*rec
;
3425 struct ftrace_page
*pg
;
3434 type
= filter_parse_regex(buffer
, strlen(buffer
), &search
, ¬);
3435 if (!not && *idx
>= FTRACE_GRAPH_MAX_FUNCS
)
3438 search_len
= strlen(search
);
3440 mutex_lock(&ftrace_lock
);
3442 if (unlikely(ftrace_disabled
)) {
3443 mutex_unlock(&ftrace_lock
);
3447 do_for_each_ftrace_rec(pg
, rec
) {
3449 if (rec
->flags
& FTRACE_FL_FREE
)
3452 if (ftrace_match_record(rec
, NULL
, search
, search_len
, type
)) {
3453 /* if it is in the array */
3455 for (i
= 0; i
< *idx
; i
++) {
3456 if (array
[i
] == rec
->ip
) {
3465 array
[(*idx
)++] = rec
->ip
;
3466 if (*idx
>= FTRACE_GRAPH_MAX_FUNCS
)
3471 array
[i
] = array
[--(*idx
)];
3477 } while_for_each_ftrace_rec();
3479 mutex_unlock(&ftrace_lock
);
3484 ftrace_graph_filter_enabled
= 1;
3489 ftrace_graph_write(struct file
*file
, const char __user
*ubuf
,
3490 size_t cnt
, loff_t
*ppos
)
3492 struct trace_parser parser
;
3498 mutex_lock(&graph_lock
);
3500 if (trace_parser_get_init(&parser
, FTRACE_BUFF_MAX
)) {
3505 read
= trace_get_user(&parser
, ubuf
, cnt
, ppos
);
3507 if (read
>= 0 && trace_parser_loaded((&parser
))) {
3508 parser
.buffer
[parser
.idx
] = 0;
3510 /* we allow only one expression at a time */
3511 ret
= ftrace_set_func(ftrace_graph_funcs
, &ftrace_graph_count
,
3520 trace_parser_put(&parser
);
3522 mutex_unlock(&graph_lock
);
3527 static const struct file_operations ftrace_graph_fops
= {
3528 .open
= ftrace_graph_open
,
3530 .write
= ftrace_graph_write
,
3531 .release
= ftrace_graph_release
,
3532 .llseek
= seq_lseek
,
3534 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3536 static __init
int ftrace_init_dyn_debugfs(struct dentry
*d_tracer
)
3539 trace_create_file("available_filter_functions", 0444,
3540 d_tracer
, NULL
, &ftrace_avail_fops
);
3542 trace_create_file("enabled_functions", 0444,
3543 d_tracer
, NULL
, &ftrace_enabled_fops
);
3545 trace_create_file("set_ftrace_filter", 0644, d_tracer
,
3546 NULL
, &ftrace_filter_fops
);
3548 trace_create_file("set_ftrace_notrace", 0644, d_tracer
,
3549 NULL
, &ftrace_notrace_fops
);
3551 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3552 trace_create_file("set_graph_function", 0444, d_tracer
,
3554 &ftrace_graph_fops
);
3555 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3560 static int ftrace_process_locs(struct module
*mod
,
3561 unsigned long *start
,
3566 unsigned long flags
= 0; /* Shut up gcc */
3568 mutex_lock(&ftrace_lock
);
3571 addr
= ftrace_call_adjust(*p
++);
3573 * Some architecture linkers will pad between
3574 * the different mcount_loc sections of different
3575 * object files to satisfy alignments.
3576 * Skip any NULL pointers.
3580 ftrace_record_ip(addr
);
3584 * We only need to disable interrupts on start up
3585 * because we are modifying code that an interrupt
3586 * may execute, and the modification is not atomic.
3587 * But for modules, nothing runs the code we modify
3588 * until we are finished with it, and there's no
3589 * reason to cause large interrupt latencies while we do it.
3592 local_irq_save(flags
);
3593 ftrace_update_code(mod
);
3595 local_irq_restore(flags
);
3596 mutex_unlock(&ftrace_lock
);
3601 #ifdef CONFIG_MODULES
3602 void ftrace_release_mod(struct module
*mod
)
3604 struct dyn_ftrace
*rec
;
3605 struct ftrace_page
*pg
;
3607 mutex_lock(&ftrace_lock
);
3609 if (ftrace_disabled
)
3612 do_for_each_ftrace_rec(pg
, rec
) {
3613 if (within_module_core(rec
->ip
, mod
)) {
3615 * rec->ip is changed in ftrace_free_rec()
3616 * It should not between s and e if record was freed.
3618 FTRACE_WARN_ON(rec
->flags
& FTRACE_FL_FREE
);
3619 ftrace_free_rec(rec
);
3621 } while_for_each_ftrace_rec();
3623 mutex_unlock(&ftrace_lock
);
3626 static void ftrace_init_module(struct module
*mod
,
3627 unsigned long *start
, unsigned long *end
)
3629 if (ftrace_disabled
|| start
== end
)
3631 ftrace_process_locs(mod
, start
, end
);
3634 static int ftrace_module_notify(struct notifier_block
*self
,
3635 unsigned long val
, void *data
)
3637 struct module
*mod
= data
;
3640 case MODULE_STATE_COMING
:
3641 ftrace_init_module(mod
, mod
->ftrace_callsites
,
3642 mod
->ftrace_callsites
+
3643 mod
->num_ftrace_callsites
);
3645 case MODULE_STATE_GOING
:
3646 ftrace_release_mod(mod
);
3653 static int ftrace_module_notify(struct notifier_block
*self
,
3654 unsigned long val
, void *data
)
3658 #endif /* CONFIG_MODULES */
3660 struct notifier_block ftrace_module_nb
= {
3661 .notifier_call
= ftrace_module_notify
,
3665 extern unsigned long __start_mcount_loc
[];
3666 extern unsigned long __stop_mcount_loc
[];
3668 void __init
ftrace_init(void)
3670 unsigned long count
, addr
, flags
;
3673 /* Keep the ftrace pointer to the stub */
3674 addr
= (unsigned long)ftrace_stub
;
3676 local_irq_save(flags
);
3677 ftrace_dyn_arch_init(&addr
);
3678 local_irq_restore(flags
);
3680 /* ftrace_dyn_arch_init places the return code in addr */
3684 count
= __stop_mcount_loc
- __start_mcount_loc
;
3686 ret
= ftrace_dyn_table_alloc(count
);
3690 last_ftrace_enabled
= ftrace_enabled
= 1;
3692 ret
= ftrace_process_locs(NULL
,
3696 ret
= register_module_notifier(&ftrace_module_nb
);
3698 pr_warning("Failed to register trace ftrace module notifier\n");
3700 set_ftrace_early_filters();
3704 ftrace_disabled
= 1;
3709 static struct ftrace_ops global_ops
= {
3710 .func
= ftrace_stub
,
3713 static int __init
ftrace_nodyn_init(void)
3718 device_initcall(ftrace_nodyn_init
);
3720 static inline int ftrace_init_dyn_debugfs(struct dentry
*d_tracer
) { return 0; }
3721 static inline void ftrace_startup_enable(int command
) { }
3722 /* Keep as macros so we do not need to define the commands */
3723 # define ftrace_startup(ops, command) \
3725 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
3728 # define ftrace_shutdown(ops, command) do { } while (0)
3729 # define ftrace_startup_sysctl() do { } while (0)
3730 # define ftrace_shutdown_sysctl() do { } while (0)
3733 ftrace_ops_test(struct ftrace_ops
*ops
, unsigned long ip
)
3738 #endif /* CONFIG_DYNAMIC_FTRACE */
3741 ftrace_ops_list_func(unsigned long ip
, unsigned long parent_ip
)
3743 struct ftrace_ops
*op
;
3745 if (unlikely(trace_recursion_test(TRACE_INTERNAL_BIT
)))
3748 trace_recursion_set(TRACE_INTERNAL_BIT
);
3750 * Some of the ops may be dynamically allocated,
3751 * they must be freed after a synchronize_sched().
3753 preempt_disable_notrace();
3754 op
= rcu_dereference_raw(ftrace_ops_list
);
3755 while (op
!= &ftrace_list_end
) {
3756 if (ftrace_ops_test(op
, ip
))
3757 op
->func(ip
, parent_ip
);
3758 op
= rcu_dereference_raw(op
->next
);
3760 preempt_enable_notrace();
3761 trace_recursion_clear(TRACE_INTERNAL_BIT
);
3764 static void clear_ftrace_swapper(void)
3766 struct task_struct
*p
;
3770 for_each_online_cpu(cpu
) {
3772 clear_tsk_trace_trace(p
);
3777 static void set_ftrace_swapper(void)
3779 struct task_struct
*p
;
3783 for_each_online_cpu(cpu
) {
3785 set_tsk_trace_trace(p
);
3790 static void clear_ftrace_pid(struct pid
*pid
)
3792 struct task_struct
*p
;
3795 do_each_pid_task(pid
, PIDTYPE_PID
, p
) {
3796 clear_tsk_trace_trace(p
);
3797 } while_each_pid_task(pid
, PIDTYPE_PID
, p
);
3803 static void set_ftrace_pid(struct pid
*pid
)
3805 struct task_struct
*p
;
3808 do_each_pid_task(pid
, PIDTYPE_PID
, p
) {
3809 set_tsk_trace_trace(p
);
3810 } while_each_pid_task(pid
, PIDTYPE_PID
, p
);
3814 static void clear_ftrace_pid_task(struct pid
*pid
)
3816 if (pid
== ftrace_swapper_pid
)
3817 clear_ftrace_swapper();
3819 clear_ftrace_pid(pid
);
3822 static void set_ftrace_pid_task(struct pid
*pid
)
3824 if (pid
== ftrace_swapper_pid
)
3825 set_ftrace_swapper();
3827 set_ftrace_pid(pid
);
3830 static int ftrace_pid_add(int p
)
3833 struct ftrace_pid
*fpid
;
3836 mutex_lock(&ftrace_lock
);
3839 pid
= ftrace_swapper_pid
;
3841 pid
= find_get_pid(p
);
3848 list_for_each_entry(fpid
, &ftrace_pids
, list
)
3849 if (fpid
->pid
== pid
)
3854 fpid
= kmalloc(sizeof(*fpid
), GFP_KERNEL
);
3858 list_add(&fpid
->list
, &ftrace_pids
);
3861 set_ftrace_pid_task(pid
);
3863 ftrace_update_pid_func();
3864 ftrace_startup_enable(0);
3866 mutex_unlock(&ftrace_lock
);
3870 if (pid
!= ftrace_swapper_pid
)
3874 mutex_unlock(&ftrace_lock
);
3878 static void ftrace_pid_reset(void)
3880 struct ftrace_pid
*fpid
, *safe
;
3882 mutex_lock(&ftrace_lock
);
3883 list_for_each_entry_safe(fpid
, safe
, &ftrace_pids
, list
) {
3884 struct pid
*pid
= fpid
->pid
;
3886 clear_ftrace_pid_task(pid
);
3888 list_del(&fpid
->list
);
3892 ftrace_update_pid_func();
3893 ftrace_startup_enable(0);
3895 mutex_unlock(&ftrace_lock
);
3898 static void *fpid_start(struct seq_file
*m
, loff_t
*pos
)
3900 mutex_lock(&ftrace_lock
);
3902 if (list_empty(&ftrace_pids
) && (!*pos
))
3905 return seq_list_start(&ftrace_pids
, *pos
);
3908 static void *fpid_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
3913 return seq_list_next(v
, &ftrace_pids
, pos
);
3916 static void fpid_stop(struct seq_file
*m
, void *p
)
3918 mutex_unlock(&ftrace_lock
);
3921 static int fpid_show(struct seq_file
*m
, void *v
)
3923 const struct ftrace_pid
*fpid
= list_entry(v
, struct ftrace_pid
, list
);
3925 if (v
== (void *)1) {
3926 seq_printf(m
, "no pid\n");
3930 if (fpid
->pid
== ftrace_swapper_pid
)
3931 seq_printf(m
, "swapper tasks\n");
3933 seq_printf(m
, "%u\n", pid_vnr(fpid
->pid
));
3938 static const struct seq_operations ftrace_pid_sops
= {
3939 .start
= fpid_start
,
3946 ftrace_pid_open(struct inode
*inode
, struct file
*file
)
3950 if ((file
->f_mode
& FMODE_WRITE
) &&
3951 (file
->f_flags
& O_TRUNC
))
3954 if (file
->f_mode
& FMODE_READ
)
3955 ret
= seq_open(file
, &ftrace_pid_sops
);
3961 ftrace_pid_write(struct file
*filp
, const char __user
*ubuf
,
3962 size_t cnt
, loff_t
*ppos
)
3968 if (cnt
>= sizeof(buf
))
3971 if (copy_from_user(&buf
, ubuf
, cnt
))
3977 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
3978 * to clean the filter quietly.
3980 tmp
= strstrip(buf
);
3981 if (strlen(tmp
) == 0)
3984 ret
= strict_strtol(tmp
, 10, &val
);
3988 ret
= ftrace_pid_add(val
);
3990 return ret
? ret
: cnt
;
3994 ftrace_pid_release(struct inode
*inode
, struct file
*file
)
3996 if (file
->f_mode
& FMODE_READ
)
3997 seq_release(inode
, file
);
4002 static const struct file_operations ftrace_pid_fops
= {
4003 .open
= ftrace_pid_open
,
4004 .write
= ftrace_pid_write
,
4006 .llseek
= seq_lseek
,
4007 .release
= ftrace_pid_release
,
4010 static __init
int ftrace_init_debugfs(void)
4012 struct dentry
*d_tracer
;
4014 d_tracer
= tracing_init_dentry();
4018 ftrace_init_dyn_debugfs(d_tracer
);
4020 trace_create_file("set_ftrace_pid", 0644, d_tracer
,
4021 NULL
, &ftrace_pid_fops
);
4023 ftrace_profile_debugfs(d_tracer
);
4027 fs_initcall(ftrace_init_debugfs
);
4030 * ftrace_kill - kill ftrace
4032 * This function should be used by panic code. It stops ftrace
4033 * but in a not so nice way. If you need to simply kill ftrace
4034 * from a non-atomic section, use ftrace_kill.
4036 void ftrace_kill(void)
4038 ftrace_disabled
= 1;
4040 clear_ftrace_function();
4044 * Test if ftrace is dead or not.
4046 int ftrace_is_dead(void)
4048 return ftrace_disabled
;
4052 * register_ftrace_function - register a function for profiling
4053 * @ops - ops structure that holds the function for profiling.
4055 * Register a function to be called by all functions in the
4058 * Note: @ops->func and all the functions it calls must be labeled
4059 * with "notrace", otherwise it will go into a
4062 int register_ftrace_function(struct ftrace_ops
*ops
)
4066 mutex_lock(&ftrace_lock
);
4068 if (unlikely(ftrace_disabled
))
4071 ret
= __register_ftrace_function(ops
);
4073 ret
= ftrace_startup(ops
, 0);
4077 mutex_unlock(&ftrace_lock
);
4080 EXPORT_SYMBOL_GPL(register_ftrace_function
);
4083 * unregister_ftrace_function - unregister a function for profiling.
4084 * @ops - ops structure that holds the function to unregister
4086 * Unregister a function that was added to be called by ftrace profiling.
4088 int unregister_ftrace_function(struct ftrace_ops
*ops
)
4092 mutex_lock(&ftrace_lock
);
4093 ret
= __unregister_ftrace_function(ops
);
4095 ftrace_shutdown(ops
, 0);
4096 mutex_unlock(&ftrace_lock
);
4100 EXPORT_SYMBOL_GPL(unregister_ftrace_function
);
4103 ftrace_enable_sysctl(struct ctl_table
*table
, int write
,
4104 void __user
*buffer
, size_t *lenp
,
4109 mutex_lock(&ftrace_lock
);
4111 if (unlikely(ftrace_disabled
))
4114 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
4116 if (ret
|| !write
|| (last_ftrace_enabled
== !!ftrace_enabled
))
4119 last_ftrace_enabled
= !!ftrace_enabled
;
4121 if (ftrace_enabled
) {
4123 ftrace_startup_sysctl();
4125 /* we are starting ftrace again */
4126 if (ftrace_ops_list
!= &ftrace_list_end
) {
4127 if (ftrace_ops_list
->next
== &ftrace_list_end
)
4128 ftrace_trace_function
= ftrace_ops_list
->func
;
4130 ftrace_trace_function
= ftrace_ops_list_func
;
4134 /* stopping ftrace calls (just send to ftrace_stub) */
4135 ftrace_trace_function
= ftrace_stub
;
4137 ftrace_shutdown_sysctl();
4141 mutex_unlock(&ftrace_lock
);
4145 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4147 static int ftrace_graph_active
;
4148 static struct notifier_block ftrace_suspend_notifier
;
4150 int ftrace_graph_entry_stub(struct ftrace_graph_ent
*trace
)
4155 /* The callbacks that hook a function */
4156 trace_func_graph_ret_t ftrace_graph_return
=
4157 (trace_func_graph_ret_t
)ftrace_stub
;
4158 trace_func_graph_ent_t ftrace_graph_entry
= ftrace_graph_entry_stub
;
4160 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
4161 static int alloc_retstack_tasklist(struct ftrace_ret_stack
**ret_stack_list
)
4165 unsigned long flags
;
4166 int start
= 0, end
= FTRACE_RETSTACK_ALLOC_SIZE
;
4167 struct task_struct
*g
, *t
;
4169 for (i
= 0; i
< FTRACE_RETSTACK_ALLOC_SIZE
; i
++) {
4170 ret_stack_list
[i
] = kmalloc(FTRACE_RETFUNC_DEPTH
4171 * sizeof(struct ftrace_ret_stack
),
4173 if (!ret_stack_list
[i
]) {
4181 read_lock_irqsave(&tasklist_lock
, flags
);
4182 do_each_thread(g
, t
) {
4188 if (t
->ret_stack
== NULL
) {
4189 atomic_set(&t
->tracing_graph_pause
, 0);
4190 atomic_set(&t
->trace_overrun
, 0);
4191 t
->curr_ret_stack
= -1;
4192 /* Make sure the tasks see the -1 first: */
4194 t
->ret_stack
= ret_stack_list
[start
++];
4196 } while_each_thread(g
, t
);
4199 read_unlock_irqrestore(&tasklist_lock
, flags
);
4201 for (i
= start
; i
< end
; i
++)
4202 kfree(ret_stack_list
[i
]);
4207 ftrace_graph_probe_sched_switch(void *ignore
,
4208 struct task_struct
*prev
, struct task_struct
*next
)
4210 unsigned long long timestamp
;
4214 * Does the user want to count the time a function was asleep.
4215 * If so, do not update the time stamps.
4217 if (trace_flags
& TRACE_ITER_SLEEP_TIME
)
4220 timestamp
= trace_clock_local();
4222 prev
->ftrace_timestamp
= timestamp
;
4224 /* only process tasks that we timestamped */
4225 if (!next
->ftrace_timestamp
)
4229 * Update all the counters in next to make up for the
4230 * time next was sleeping.
4232 timestamp
-= next
->ftrace_timestamp
;
4234 for (index
= next
->curr_ret_stack
; index
>= 0; index
--)
4235 next
->ret_stack
[index
].calltime
+= timestamp
;
4238 /* Allocate a return stack for each task */
4239 static int start_graph_tracing(void)
4241 struct ftrace_ret_stack
**ret_stack_list
;
4244 ret_stack_list
= kmalloc(FTRACE_RETSTACK_ALLOC_SIZE
*
4245 sizeof(struct ftrace_ret_stack
*),
4248 if (!ret_stack_list
)
4251 /* The cpu_boot init_task->ret_stack will never be freed */
4252 for_each_online_cpu(cpu
) {
4253 if (!idle_task(cpu
)->ret_stack
)
4254 ftrace_graph_init_idle_task(idle_task(cpu
), cpu
);
4258 ret
= alloc_retstack_tasklist(ret_stack_list
);
4259 } while (ret
== -EAGAIN
);
4262 ret
= register_trace_sched_switch(ftrace_graph_probe_sched_switch
, NULL
);
4264 pr_info("ftrace_graph: Couldn't activate tracepoint"
4265 " probe to kernel_sched_switch\n");
4268 kfree(ret_stack_list
);
4273 * Hibernation protection.
4274 * The state of the current task is too much unstable during
4275 * suspend/restore to disk. We want to protect against that.
4278 ftrace_suspend_notifier_call(struct notifier_block
*bl
, unsigned long state
,
4282 case PM_HIBERNATION_PREPARE
:
4283 pause_graph_tracing();
4286 case PM_POST_HIBERNATION
:
4287 unpause_graph_tracing();
4293 int register_ftrace_graph(trace_func_graph_ret_t retfunc
,
4294 trace_func_graph_ent_t entryfunc
)
4298 mutex_lock(&ftrace_lock
);
4300 /* we currently allow only one tracer registered at a time */
4301 if (ftrace_graph_active
) {
4306 ftrace_suspend_notifier
.notifier_call
= ftrace_suspend_notifier_call
;
4307 register_pm_notifier(&ftrace_suspend_notifier
);
4309 ftrace_graph_active
++;
4310 ret
= start_graph_tracing();
4312 ftrace_graph_active
--;
4316 ftrace_graph_return
= retfunc
;
4317 ftrace_graph_entry
= entryfunc
;
4319 ret
= ftrace_startup(&global_ops
, FTRACE_START_FUNC_RET
);
4322 mutex_unlock(&ftrace_lock
);
4326 void unregister_ftrace_graph(void)
4328 mutex_lock(&ftrace_lock
);
4330 if (unlikely(!ftrace_graph_active
))
4333 ftrace_graph_active
--;
4334 ftrace_graph_return
= (trace_func_graph_ret_t
)ftrace_stub
;
4335 ftrace_graph_entry
= ftrace_graph_entry_stub
;
4336 ftrace_shutdown(&global_ops
, FTRACE_STOP_FUNC_RET
);
4337 unregister_pm_notifier(&ftrace_suspend_notifier
);
4338 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch
, NULL
);
4341 mutex_unlock(&ftrace_lock
);
4344 static DEFINE_PER_CPU(struct ftrace_ret_stack
*, idle_ret_stack
);
4347 graph_init_task(struct task_struct
*t
, struct ftrace_ret_stack
*ret_stack
)
4349 atomic_set(&t
->tracing_graph_pause
, 0);
4350 atomic_set(&t
->trace_overrun
, 0);
4351 t
->ftrace_timestamp
= 0;
4352 /* make curr_ret_stack visible before we add the ret_stack */
4354 t
->ret_stack
= ret_stack
;
4358 * Allocate a return stack for the idle task. May be the first
4359 * time through, or it may be done by CPU hotplug online.
4361 void ftrace_graph_init_idle_task(struct task_struct
*t
, int cpu
)
4363 t
->curr_ret_stack
= -1;
4365 * The idle task has no parent, it either has its own
4366 * stack or no stack at all.
4369 WARN_ON(t
->ret_stack
!= per_cpu(idle_ret_stack
, cpu
));
4371 if (ftrace_graph_active
) {
4372 struct ftrace_ret_stack
*ret_stack
;
4374 ret_stack
= per_cpu(idle_ret_stack
, cpu
);
4376 ret_stack
= kmalloc(FTRACE_RETFUNC_DEPTH
4377 * sizeof(struct ftrace_ret_stack
),
4381 per_cpu(idle_ret_stack
, cpu
) = ret_stack
;
4383 graph_init_task(t
, ret_stack
);
4387 /* Allocate a return stack for newly created task */
4388 void ftrace_graph_init_task(struct task_struct
*t
)
4390 /* Make sure we do not use the parent ret_stack */
4391 t
->ret_stack
= NULL
;
4392 t
->curr_ret_stack
= -1;
4394 if (ftrace_graph_active
) {
4395 struct ftrace_ret_stack
*ret_stack
;
4397 ret_stack
= kmalloc(FTRACE_RETFUNC_DEPTH
4398 * sizeof(struct ftrace_ret_stack
),
4402 graph_init_task(t
, ret_stack
);
4406 void ftrace_graph_exit_task(struct task_struct
*t
)
4408 struct ftrace_ret_stack
*ret_stack
= t
->ret_stack
;
4410 t
->ret_stack
= NULL
;
4411 /* NULL must become visible to IRQs before we free it: */
4417 void ftrace_graph_stop(void)