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/ftrace.h>
26 #include <linux/sysctl.h>
27 #include <linux/slab.h>
28 #include <linux/ctype.h>
29 #include <linux/list.h>
30 #include <linux/hash.h>
31 #include <linux/rcupdate.h>
33 #include <trace/events/sched.h>
35 #include <asm/setup.h>
37 #include "trace_output.h"
38 #include "trace_stat.h"
40 #define FTRACE_WARN_ON(cond) \
48 #define FTRACE_WARN_ON_ONCE(cond) \
51 if (WARN_ON_ONCE(___r)) \
56 /* hash bits for specific function selection */
57 #define FTRACE_HASH_BITS 7
58 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
59 #define FTRACE_HASH_DEFAULT_BITS 10
60 #define FTRACE_HASH_MAX_BITS 12
62 /* ftrace_enabled is a method to turn ftrace on or off */
63 int ftrace_enabled __read_mostly
;
64 static int last_ftrace_enabled
;
66 /* Quick disabling of function tracer. */
67 int function_trace_stop
;
69 /* List for set_ftrace_pid's pids. */
70 LIST_HEAD(ftrace_pids
);
72 struct list_head list
;
77 * ftrace_disabled is set when an anomaly is discovered.
78 * ftrace_disabled is much stronger than ftrace_enabled.
80 static int ftrace_disabled __read_mostly
;
82 static DEFINE_MUTEX(ftrace_lock
);
84 static struct ftrace_ops ftrace_list_end __read_mostly
= {
88 static struct ftrace_ops
*ftrace_global_list __read_mostly
= &ftrace_list_end
;
89 static struct ftrace_ops
*ftrace_ops_list __read_mostly
= &ftrace_list_end
;
90 ftrace_func_t ftrace_trace_function __read_mostly
= ftrace_stub
;
91 ftrace_func_t __ftrace_trace_function __read_mostly
= ftrace_stub
;
92 ftrace_func_t ftrace_pid_function __read_mostly
= ftrace_stub
;
93 static struct ftrace_ops global_ops
;
96 ftrace_ops_list_func(unsigned long ip
, unsigned long parent_ip
);
99 * Traverse the ftrace_global_list, invoking all entries. The reason that we
100 * can use rcu_dereference_raw() is that elements removed from this list
101 * are simply leaked, so there is no need to interact with a grace-period
102 * mechanism. The rcu_dereference_raw() calls are needed to handle
103 * concurrent insertions into the ftrace_global_list.
105 * Silly Alpha and silly pointer-speculation compiler optimizations!
107 static void ftrace_global_list_func(unsigned long ip
,
108 unsigned long parent_ip
)
110 struct ftrace_ops
*op
;
112 if (unlikely(trace_recursion_test(TRACE_GLOBAL_BIT
)))
115 trace_recursion_set(TRACE_GLOBAL_BIT
);
116 op
= rcu_dereference_raw(ftrace_global_list
); /*see above*/
117 while (op
!= &ftrace_list_end
) {
118 op
->func(ip
, parent_ip
);
119 op
= rcu_dereference_raw(op
->next
); /*see above*/
121 trace_recursion_clear(TRACE_GLOBAL_BIT
);
124 static void ftrace_pid_func(unsigned long ip
, unsigned long parent_ip
)
126 if (!test_tsk_trace_trace(current
))
129 ftrace_pid_function(ip
, parent_ip
);
132 static void set_ftrace_pid_function(ftrace_func_t func
)
134 /* do not set ftrace_pid_function to itself! */
135 if (func
!= ftrace_pid_func
)
136 ftrace_pid_function
= func
;
140 * clear_ftrace_function - reset the ftrace function
142 * This NULLs the ftrace function and in essence stops
143 * tracing. There may be lag
145 void clear_ftrace_function(void)
147 ftrace_trace_function
= ftrace_stub
;
148 __ftrace_trace_function
= ftrace_stub
;
149 ftrace_pid_function
= ftrace_stub
;
152 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
154 * For those archs that do not test ftrace_trace_stop in their
155 * mcount call site, we need to do it from C.
157 static void ftrace_test_stop_func(unsigned long ip
, unsigned long parent_ip
)
159 if (function_trace_stop
)
162 __ftrace_trace_function(ip
, parent_ip
);
166 static void update_global_ops(void)
171 * If there's only one function registered, then call that
172 * function directly. Otherwise, we need to iterate over the
173 * registered callers.
175 if (ftrace_global_list
== &ftrace_list_end
||
176 ftrace_global_list
->next
== &ftrace_list_end
)
177 func
= ftrace_global_list
->func
;
179 func
= ftrace_global_list_func
;
181 /* If we filter on pids, update to use the pid function */
182 if (!list_empty(&ftrace_pids
)) {
183 set_ftrace_pid_function(func
);
184 func
= ftrace_pid_func
;
187 global_ops
.func
= func
;
190 static void update_ftrace_function(void)
197 * If we are at the end of the list and this ops is
198 * not dynamic, then have the mcount trampoline call
199 * the function directly
201 if (ftrace_ops_list
== &ftrace_list_end
||
202 (ftrace_ops_list
->next
== &ftrace_list_end
&&
203 !(ftrace_ops_list
->flags
& FTRACE_OPS_FL_DYNAMIC
)))
204 func
= ftrace_ops_list
->func
;
206 func
= ftrace_ops_list_func
;
208 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
209 ftrace_trace_function
= func
;
211 __ftrace_trace_function
= func
;
212 ftrace_trace_function
= ftrace_test_stop_func
;
216 static void add_ftrace_ops(struct ftrace_ops
**list
, struct ftrace_ops
*ops
)
220 * We are entering ops into the list but another
221 * CPU might be walking that list. We need to make sure
222 * the ops->next pointer is valid before another CPU sees
223 * the ops pointer included into the list.
225 rcu_assign_pointer(*list
, ops
);
228 static int remove_ftrace_ops(struct ftrace_ops
**list
, struct ftrace_ops
*ops
)
230 struct ftrace_ops
**p
;
233 * If we are removing the last function, then simply point
234 * to the ftrace_stub.
236 if (*list
== ops
&& ops
->next
== &ftrace_list_end
) {
237 *list
= &ftrace_list_end
;
241 for (p
= list
; *p
!= &ftrace_list_end
; p
= &(*p
)->next
)
252 static int __register_ftrace_function(struct ftrace_ops
*ops
)
257 if (FTRACE_WARN_ON(ops
== &global_ops
))
260 if (WARN_ON(ops
->flags
& FTRACE_OPS_FL_ENABLED
))
263 if (!core_kernel_data((unsigned long)ops
))
264 ops
->flags
|= FTRACE_OPS_FL_DYNAMIC
;
266 if (ops
->flags
& FTRACE_OPS_FL_GLOBAL
) {
267 int first
= ftrace_global_list
== &ftrace_list_end
;
268 add_ftrace_ops(&ftrace_global_list
, ops
);
269 ops
->flags
|= FTRACE_OPS_FL_ENABLED
;
271 add_ftrace_ops(&ftrace_ops_list
, &global_ops
);
273 add_ftrace_ops(&ftrace_ops_list
, ops
);
276 update_ftrace_function();
281 static int __unregister_ftrace_function(struct ftrace_ops
*ops
)
288 if (WARN_ON(!(ops
->flags
& FTRACE_OPS_FL_ENABLED
)))
291 if (FTRACE_WARN_ON(ops
== &global_ops
))
294 if (ops
->flags
& FTRACE_OPS_FL_GLOBAL
) {
295 ret
= remove_ftrace_ops(&ftrace_global_list
, ops
);
296 if (!ret
&& ftrace_global_list
== &ftrace_list_end
)
297 ret
= remove_ftrace_ops(&ftrace_ops_list
, &global_ops
);
299 ops
->flags
&= ~FTRACE_OPS_FL_ENABLED
;
301 ret
= remove_ftrace_ops(&ftrace_ops_list
, ops
);
307 update_ftrace_function();
310 * Dynamic ops may be freed, we must make sure that all
311 * callers are done before leaving this function.
313 if (ops
->flags
& FTRACE_OPS_FL_DYNAMIC
)
319 static void ftrace_update_pid_func(void)
321 /* Only do something if we are tracing something */
322 if (ftrace_trace_function
== ftrace_stub
)
325 update_ftrace_function();
328 #ifdef CONFIG_FUNCTION_PROFILER
329 struct ftrace_profile
{
330 struct hlist_node node
;
332 unsigned long counter
;
333 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
334 unsigned long long time
;
335 unsigned long long time_squared
;
339 struct ftrace_profile_page
{
340 struct ftrace_profile_page
*next
;
342 struct ftrace_profile records
[];
345 struct ftrace_profile_stat
{
347 struct hlist_head
*hash
;
348 struct ftrace_profile_page
*pages
;
349 struct ftrace_profile_page
*start
;
350 struct tracer_stat stat
;
353 #define PROFILE_RECORDS_SIZE \
354 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
356 #define PROFILES_PER_PAGE \
357 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
359 static int ftrace_profile_bits __read_mostly
;
360 static int ftrace_profile_enabled __read_mostly
;
362 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
363 static DEFINE_MUTEX(ftrace_profile_lock
);
365 static DEFINE_PER_CPU(struct ftrace_profile_stat
, ftrace_profile_stats
);
367 #define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
370 function_stat_next(void *v
, int idx
)
372 struct ftrace_profile
*rec
= v
;
373 struct ftrace_profile_page
*pg
;
375 pg
= (struct ftrace_profile_page
*)((unsigned long)rec
& PAGE_MASK
);
381 if ((void *)rec
>= (void *)&pg
->records
[pg
->index
]) {
385 rec
= &pg
->records
[0];
393 static void *function_stat_start(struct tracer_stat
*trace
)
395 struct ftrace_profile_stat
*stat
=
396 container_of(trace
, struct ftrace_profile_stat
, stat
);
398 if (!stat
|| !stat
->start
)
401 return function_stat_next(&stat
->start
->records
[0], 0);
404 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
405 /* function graph compares on total time */
406 static int function_stat_cmp(void *p1
, void *p2
)
408 struct ftrace_profile
*a
= p1
;
409 struct ftrace_profile
*b
= p2
;
411 if (a
->time
< b
->time
)
413 if (a
->time
> b
->time
)
419 /* not function graph compares against hits */
420 static int function_stat_cmp(void *p1
, void *p2
)
422 struct ftrace_profile
*a
= p1
;
423 struct ftrace_profile
*b
= p2
;
425 if (a
->counter
< b
->counter
)
427 if (a
->counter
> b
->counter
)
434 static int function_stat_headers(struct seq_file
*m
)
436 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
437 seq_printf(m
, " Function "
440 "--- ---- --- ---\n");
442 seq_printf(m
, " Function Hit\n"
448 static int function_stat_show(struct seq_file
*m
, void *v
)
450 struct ftrace_profile
*rec
= v
;
451 char str
[KSYM_SYMBOL_LEN
];
453 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
454 static struct trace_seq s
;
455 unsigned long long avg
;
456 unsigned long long stddev
;
458 mutex_lock(&ftrace_profile_lock
);
460 /* we raced with function_profile_reset() */
461 if (unlikely(rec
->counter
== 0)) {
466 kallsyms_lookup(rec
->ip
, NULL
, NULL
, NULL
, str
);
467 seq_printf(m
, " %-30.30s %10lu", str
, rec
->counter
);
469 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
472 do_div(avg
, rec
->counter
);
474 /* Sample standard deviation (s^2) */
475 if (rec
->counter
<= 1)
478 stddev
= rec
->time_squared
- rec
->counter
* avg
* avg
;
480 * Divide only 1000 for ns^2 -> us^2 conversion.
481 * trace_print_graph_duration will divide 1000 again.
483 do_div(stddev
, (rec
->counter
- 1) * 1000);
487 trace_print_graph_duration(rec
->time
, &s
);
488 trace_seq_puts(&s
, " ");
489 trace_print_graph_duration(avg
, &s
);
490 trace_seq_puts(&s
, " ");
491 trace_print_graph_duration(stddev
, &s
);
492 trace_print_seq(m
, &s
);
496 mutex_unlock(&ftrace_profile_lock
);
501 static void ftrace_profile_reset(struct ftrace_profile_stat
*stat
)
503 struct ftrace_profile_page
*pg
;
505 pg
= stat
->pages
= stat
->start
;
508 memset(pg
->records
, 0, PROFILE_RECORDS_SIZE
);
513 memset(stat
->hash
, 0,
514 FTRACE_PROFILE_HASH_SIZE
* sizeof(struct hlist_head
));
517 int ftrace_profile_pages_init(struct ftrace_profile_stat
*stat
)
519 struct ftrace_profile_page
*pg
;
524 /* If we already allocated, do nothing */
528 stat
->pages
= (void *)get_zeroed_page(GFP_KERNEL
);
532 #ifdef CONFIG_DYNAMIC_FTRACE
533 functions
= ftrace_update_tot_cnt
;
536 * We do not know the number of functions that exist because
537 * dynamic tracing is what counts them. With past experience
538 * we have around 20K functions. That should be more than enough.
539 * It is highly unlikely we will execute every function in
545 pg
= stat
->start
= stat
->pages
;
547 pages
= DIV_ROUND_UP(functions
, PROFILES_PER_PAGE
);
549 for (i
= 0; i
< pages
; i
++) {
550 pg
->next
= (void *)get_zeroed_page(GFP_KERNEL
);
561 unsigned long tmp
= (unsigned long)pg
;
567 free_page((unsigned long)stat
->pages
);
574 static int ftrace_profile_init_cpu(int cpu
)
576 struct ftrace_profile_stat
*stat
;
579 stat
= &per_cpu(ftrace_profile_stats
, cpu
);
582 /* If the profile is already created, simply reset it */
583 ftrace_profile_reset(stat
);
588 * We are profiling all functions, but usually only a few thousand
589 * functions are hit. We'll make a hash of 1024 items.
591 size
= FTRACE_PROFILE_HASH_SIZE
;
593 stat
->hash
= kzalloc(sizeof(struct hlist_head
) * size
, GFP_KERNEL
);
598 if (!ftrace_profile_bits
) {
601 for (; size
; size
>>= 1)
602 ftrace_profile_bits
++;
605 /* Preallocate the function profiling pages */
606 if (ftrace_profile_pages_init(stat
) < 0) {
615 static int ftrace_profile_init(void)
620 for_each_online_cpu(cpu
) {
621 ret
= ftrace_profile_init_cpu(cpu
);
629 /* interrupts must be disabled */
630 static struct ftrace_profile
*
631 ftrace_find_profiled_func(struct ftrace_profile_stat
*stat
, unsigned long ip
)
633 struct ftrace_profile
*rec
;
634 struct hlist_head
*hhd
;
635 struct hlist_node
*n
;
638 key
= hash_long(ip
, ftrace_profile_bits
);
639 hhd
= &stat
->hash
[key
];
641 if (hlist_empty(hhd
))
644 hlist_for_each_entry_rcu(rec
, n
, hhd
, node
) {
652 static void ftrace_add_profile(struct ftrace_profile_stat
*stat
,
653 struct ftrace_profile
*rec
)
657 key
= hash_long(rec
->ip
, ftrace_profile_bits
);
658 hlist_add_head_rcu(&rec
->node
, &stat
->hash
[key
]);
662 * The memory is already allocated, this simply finds a new record to use.
664 static struct ftrace_profile
*
665 ftrace_profile_alloc(struct ftrace_profile_stat
*stat
, unsigned long ip
)
667 struct ftrace_profile
*rec
= NULL
;
669 /* prevent recursion (from NMIs) */
670 if (atomic_inc_return(&stat
->disabled
) != 1)
674 * Try to find the function again since an NMI
675 * could have added it
677 rec
= ftrace_find_profiled_func(stat
, ip
);
681 if (stat
->pages
->index
== PROFILES_PER_PAGE
) {
682 if (!stat
->pages
->next
)
684 stat
->pages
= stat
->pages
->next
;
687 rec
= &stat
->pages
->records
[stat
->pages
->index
++];
689 ftrace_add_profile(stat
, rec
);
692 atomic_dec(&stat
->disabled
);
698 function_profile_call(unsigned long ip
, unsigned long parent_ip
)
700 struct ftrace_profile_stat
*stat
;
701 struct ftrace_profile
*rec
;
704 if (!ftrace_profile_enabled
)
707 local_irq_save(flags
);
709 stat
= &__get_cpu_var(ftrace_profile_stats
);
710 if (!stat
->hash
|| !ftrace_profile_enabled
)
713 rec
= ftrace_find_profiled_func(stat
, ip
);
715 rec
= ftrace_profile_alloc(stat
, ip
);
722 local_irq_restore(flags
);
725 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
726 static int profile_graph_entry(struct ftrace_graph_ent
*trace
)
728 function_profile_call(trace
->func
, 0);
732 static void profile_graph_return(struct ftrace_graph_ret
*trace
)
734 struct ftrace_profile_stat
*stat
;
735 unsigned long long calltime
;
736 struct ftrace_profile
*rec
;
739 local_irq_save(flags
);
740 stat
= &__get_cpu_var(ftrace_profile_stats
);
741 if (!stat
->hash
|| !ftrace_profile_enabled
)
744 /* If the calltime was zero'd ignore it */
745 if (!trace
->calltime
)
748 calltime
= trace
->rettime
- trace
->calltime
;
750 if (!(trace_flags
& TRACE_ITER_GRAPH_TIME
)) {
753 index
= trace
->depth
;
755 /* Append this call time to the parent time to subtract */
757 current
->ret_stack
[index
- 1].subtime
+= calltime
;
759 if (current
->ret_stack
[index
].subtime
< calltime
)
760 calltime
-= current
->ret_stack
[index
].subtime
;
765 rec
= ftrace_find_profiled_func(stat
, trace
->func
);
767 rec
->time
+= calltime
;
768 rec
->time_squared
+= calltime
* calltime
;
772 local_irq_restore(flags
);
775 static int register_ftrace_profiler(void)
777 return register_ftrace_graph(&profile_graph_return
,
778 &profile_graph_entry
);
781 static void unregister_ftrace_profiler(void)
783 unregister_ftrace_graph();
786 static struct ftrace_ops ftrace_profile_ops __read_mostly
= {
787 .func
= function_profile_call
,
790 static int register_ftrace_profiler(void)
792 return register_ftrace_function(&ftrace_profile_ops
);
795 static void unregister_ftrace_profiler(void)
797 unregister_ftrace_function(&ftrace_profile_ops
);
799 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
802 ftrace_profile_write(struct file
*filp
, const char __user
*ubuf
,
803 size_t cnt
, loff_t
*ppos
)
808 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
814 mutex_lock(&ftrace_profile_lock
);
815 if (ftrace_profile_enabled
^ val
) {
817 ret
= ftrace_profile_init();
823 ret
= register_ftrace_profiler();
828 ftrace_profile_enabled
= 1;
830 ftrace_profile_enabled
= 0;
832 * unregister_ftrace_profiler calls stop_machine
833 * so this acts like an synchronize_sched.
835 unregister_ftrace_profiler();
839 mutex_unlock(&ftrace_profile_lock
);
847 ftrace_profile_read(struct file
*filp
, char __user
*ubuf
,
848 size_t cnt
, loff_t
*ppos
)
850 char buf
[64]; /* big enough to hold a number */
853 r
= sprintf(buf
, "%u\n", ftrace_profile_enabled
);
854 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
857 static const struct file_operations ftrace_profile_fops
= {
858 .open
= tracing_open_generic
,
859 .read
= ftrace_profile_read
,
860 .write
= ftrace_profile_write
,
861 .llseek
= default_llseek
,
864 /* used to initialize the real stat files */
865 static struct tracer_stat function_stats __initdata
= {
867 .stat_start
= function_stat_start
,
868 .stat_next
= function_stat_next
,
869 .stat_cmp
= function_stat_cmp
,
870 .stat_headers
= function_stat_headers
,
871 .stat_show
= function_stat_show
874 static __init
void ftrace_profile_debugfs(struct dentry
*d_tracer
)
876 struct ftrace_profile_stat
*stat
;
877 struct dentry
*entry
;
882 for_each_possible_cpu(cpu
) {
883 stat
= &per_cpu(ftrace_profile_stats
, cpu
);
885 /* allocate enough for function name + cpu number */
886 name
= kmalloc(32, GFP_KERNEL
);
889 * The files created are permanent, if something happens
890 * we still do not free memory.
893 "Could not allocate stat file for cpu %d\n",
897 stat
->stat
= function_stats
;
898 snprintf(name
, 32, "function%d", cpu
);
899 stat
->stat
.name
= name
;
900 ret
= register_stat_tracer(&stat
->stat
);
903 "Could not register function stat for cpu %d\n",
910 entry
= debugfs_create_file("function_profile_enabled", 0644,
911 d_tracer
, NULL
, &ftrace_profile_fops
);
913 pr_warning("Could not create debugfs "
914 "'function_profile_enabled' entry\n");
917 #else /* CONFIG_FUNCTION_PROFILER */
918 static __init
void ftrace_profile_debugfs(struct dentry
*d_tracer
)
921 #endif /* CONFIG_FUNCTION_PROFILER */
923 static struct pid
* const ftrace_swapper_pid
= &init_struct_pid
;
925 #ifdef CONFIG_DYNAMIC_FTRACE
927 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
928 # error Dynamic ftrace depends on MCOUNT_RECORD
931 static struct hlist_head ftrace_func_hash
[FTRACE_FUNC_HASHSIZE
] __read_mostly
;
933 struct ftrace_func_probe
{
934 struct hlist_node node
;
935 struct ftrace_probe_ops
*ops
;
943 FTRACE_ENABLE_CALLS
= (1 << 0),
944 FTRACE_DISABLE_CALLS
= (1 << 1),
945 FTRACE_UPDATE_TRACE_FUNC
= (1 << 2),
946 FTRACE_START_FUNC_RET
= (1 << 3),
947 FTRACE_STOP_FUNC_RET
= (1 << 4),
949 struct ftrace_func_entry
{
950 struct hlist_node hlist
;
955 unsigned long size_bits
;
956 struct hlist_head
*buckets
;
962 * We make these constant because no one should touch them,
963 * but they are used as the default "empty hash", to avoid allocating
964 * it all the time. These are in a read only section such that if
965 * anyone does try to modify it, it will cause an exception.
967 static const struct hlist_head empty_buckets
[1];
968 static const struct ftrace_hash empty_hash
= {
969 .buckets
= (struct hlist_head
*)empty_buckets
,
971 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
973 static struct ftrace_ops global_ops
= {
975 .notrace_hash
= EMPTY_HASH
,
976 .filter_hash
= EMPTY_HASH
,
979 static struct dyn_ftrace
*ftrace_new_addrs
;
981 static DEFINE_MUTEX(ftrace_regex_lock
);
984 struct ftrace_page
*next
;
986 struct dyn_ftrace records
[];
989 #define ENTRIES_PER_PAGE \
990 ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
992 /* estimate from running different kernels */
993 #define NR_TO_INIT 10000
995 static struct ftrace_page
*ftrace_pages_start
;
996 static struct ftrace_page
*ftrace_pages
;
998 static struct dyn_ftrace
*ftrace_free_records
;
1000 static struct ftrace_func_entry
*
1001 ftrace_lookup_ip(struct ftrace_hash
*hash
, unsigned long ip
)
1004 struct ftrace_func_entry
*entry
;
1005 struct hlist_head
*hhd
;
1006 struct hlist_node
*n
;
1011 if (hash
->size_bits
> 0)
1012 key
= hash_long(ip
, hash
->size_bits
);
1016 hhd
= &hash
->buckets
[key
];
1018 hlist_for_each_entry_rcu(entry
, n
, hhd
, hlist
) {
1019 if (entry
->ip
== ip
)
1025 static void __add_hash_entry(struct ftrace_hash
*hash
,
1026 struct ftrace_func_entry
*entry
)
1028 struct hlist_head
*hhd
;
1031 if (hash
->size_bits
)
1032 key
= hash_long(entry
->ip
, hash
->size_bits
);
1036 hhd
= &hash
->buckets
[key
];
1037 hlist_add_head(&entry
->hlist
, hhd
);
1041 static int add_hash_entry(struct ftrace_hash
*hash
, unsigned long ip
)
1043 struct ftrace_func_entry
*entry
;
1045 entry
= kmalloc(sizeof(*entry
), GFP_KERNEL
);
1050 __add_hash_entry(hash
, entry
);
1056 free_hash_entry(struct ftrace_hash
*hash
,
1057 struct ftrace_func_entry
*entry
)
1059 hlist_del(&entry
->hlist
);
1065 remove_hash_entry(struct ftrace_hash
*hash
,
1066 struct ftrace_func_entry
*entry
)
1068 hlist_del(&entry
->hlist
);
1072 static void ftrace_hash_clear(struct ftrace_hash
*hash
)
1074 struct hlist_head
*hhd
;
1075 struct hlist_node
*tp
, *tn
;
1076 struct ftrace_func_entry
*entry
;
1077 int size
= 1 << hash
->size_bits
;
1083 for (i
= 0; i
< size
; i
++) {
1084 hhd
= &hash
->buckets
[i
];
1085 hlist_for_each_entry_safe(entry
, tp
, tn
, hhd
, hlist
)
1086 free_hash_entry(hash
, entry
);
1088 FTRACE_WARN_ON(hash
->count
);
1091 static void free_ftrace_hash(struct ftrace_hash
*hash
)
1093 if (!hash
|| hash
== EMPTY_HASH
)
1095 ftrace_hash_clear(hash
);
1096 kfree(hash
->buckets
);
1100 static void __free_ftrace_hash_rcu(struct rcu_head
*rcu
)
1102 struct ftrace_hash
*hash
;
1104 hash
= container_of(rcu
, struct ftrace_hash
, rcu
);
1105 free_ftrace_hash(hash
);
1108 static void free_ftrace_hash_rcu(struct ftrace_hash
*hash
)
1110 if (!hash
|| hash
== EMPTY_HASH
)
1112 call_rcu_sched(&hash
->rcu
, __free_ftrace_hash_rcu
);
1115 static struct ftrace_hash
*alloc_ftrace_hash(int size_bits
)
1117 struct ftrace_hash
*hash
;
1120 hash
= kzalloc(sizeof(*hash
), GFP_KERNEL
);
1124 size
= 1 << size_bits
;
1125 hash
->buckets
= kzalloc(sizeof(*hash
->buckets
) * size
, GFP_KERNEL
);
1127 if (!hash
->buckets
) {
1132 hash
->size_bits
= size_bits
;
1137 static struct ftrace_hash
*
1138 alloc_and_copy_ftrace_hash(int size_bits
, struct ftrace_hash
*hash
)
1140 struct ftrace_func_entry
*entry
;
1141 struct ftrace_hash
*new_hash
;
1142 struct hlist_node
*tp
;
1147 new_hash
= alloc_ftrace_hash(size_bits
);
1152 if (!hash
|| !hash
->count
)
1155 size
= 1 << hash
->size_bits
;
1156 for (i
= 0; i
< size
; i
++) {
1157 hlist_for_each_entry(entry
, tp
, &hash
->buckets
[i
], hlist
) {
1158 ret
= add_hash_entry(new_hash
, entry
->ip
);
1164 FTRACE_WARN_ON(new_hash
->count
!= hash
->count
);
1169 free_ftrace_hash(new_hash
);
1174 ftrace_hash_move(struct ftrace_hash
**dst
, struct ftrace_hash
*src
)
1176 struct ftrace_func_entry
*entry
;
1177 struct hlist_node
*tp
, *tn
;
1178 struct hlist_head
*hhd
;
1179 struct ftrace_hash
*old_hash
;
1180 struct ftrace_hash
*new_hash
;
1182 int size
= src
->count
;
1187 * If the new source is empty, just free dst and assign it
1191 free_ftrace_hash_rcu(*dst
);
1192 rcu_assign_pointer(*dst
, EMPTY_HASH
);
1197 * Make the hash size about 1/2 the # found
1199 for (size
/= 2; size
; size
>>= 1)
1202 /* Don't allocate too much */
1203 if (bits
> FTRACE_HASH_MAX_BITS
)
1204 bits
= FTRACE_HASH_MAX_BITS
;
1206 new_hash
= alloc_ftrace_hash(bits
);
1210 size
= 1 << src
->size_bits
;
1211 for (i
= 0; i
< size
; i
++) {
1212 hhd
= &src
->buckets
[i
];
1213 hlist_for_each_entry_safe(entry
, tp
, tn
, hhd
, hlist
) {
1215 key
= hash_long(entry
->ip
, bits
);
1218 remove_hash_entry(src
, entry
);
1219 __add_hash_entry(new_hash
, entry
);
1224 rcu_assign_pointer(*dst
, new_hash
);
1225 free_ftrace_hash_rcu(old_hash
);
1231 * Test the hashes for this ops to see if we want to call
1232 * the ops->func or not.
1234 * It's a match if the ip is in the ops->filter_hash or
1235 * the filter_hash does not exist or is empty,
1237 * the ip is not in the ops->notrace_hash.
1239 * This needs to be called with preemption disabled as
1240 * the hashes are freed with call_rcu_sched().
1243 ftrace_ops_test(struct ftrace_ops
*ops
, unsigned long ip
)
1245 struct ftrace_hash
*filter_hash
;
1246 struct ftrace_hash
*notrace_hash
;
1249 filter_hash
= rcu_dereference_raw(ops
->filter_hash
);
1250 notrace_hash
= rcu_dereference_raw(ops
->notrace_hash
);
1252 if ((!filter_hash
|| !filter_hash
->count
||
1253 ftrace_lookup_ip(filter_hash
, ip
)) &&
1254 (!notrace_hash
|| !notrace_hash
->count
||
1255 !ftrace_lookup_ip(notrace_hash
, ip
)))
1264 * This is a double for. Do not use 'break' to break out of the loop,
1265 * you must use a goto.
1267 #define do_for_each_ftrace_rec(pg, rec) \
1268 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1270 for (_____i = 0; _____i < pg->index; _____i++) { \
1271 rec = &pg->records[_____i];
1273 #define while_for_each_ftrace_rec() \
1277 static void __ftrace_hash_rec_update(struct ftrace_ops
*ops
,
1281 struct ftrace_hash
*hash
;
1282 struct ftrace_hash
*other_hash
;
1283 struct ftrace_page
*pg
;
1284 struct dyn_ftrace
*rec
;
1288 /* Only update if the ops has been registered */
1289 if (!(ops
->flags
& FTRACE_OPS_FL_ENABLED
))
1293 * In the filter_hash case:
1294 * If the count is zero, we update all records.
1295 * Otherwise we just update the items in the hash.
1297 * In the notrace_hash case:
1298 * We enable the update in the hash.
1299 * As disabling notrace means enabling the tracing,
1300 * and enabling notrace means disabling, the inc variable
1304 hash
= ops
->filter_hash
;
1305 other_hash
= ops
->notrace_hash
;
1306 if (!hash
|| !hash
->count
)
1310 hash
= ops
->notrace_hash
;
1311 other_hash
= ops
->filter_hash
;
1313 * If the notrace hash has no items,
1314 * then there's nothing to do.
1316 if (hash
&& !hash
->count
)
1320 do_for_each_ftrace_rec(pg
, rec
) {
1321 int in_other_hash
= 0;
1327 * Only the filter_hash affects all records.
1328 * Update if the record is not in the notrace hash.
1330 if (!other_hash
|| !ftrace_lookup_ip(other_hash
, rec
->ip
))
1333 in_hash
= hash
&& !!ftrace_lookup_ip(hash
, rec
->ip
);
1334 in_other_hash
= other_hash
&& !!ftrace_lookup_ip(other_hash
, rec
->ip
);
1339 if (filter_hash
&& in_hash
&& !in_other_hash
)
1341 else if (!filter_hash
&& in_hash
&&
1342 (in_other_hash
|| !other_hash
->count
))
1350 if (FTRACE_WARN_ON((rec
->flags
& ~FTRACE_FL_MASK
) == FTRACE_REF_MAX
))
1353 if (FTRACE_WARN_ON((rec
->flags
& ~FTRACE_FL_MASK
) == 0))
1358 /* Shortcut, if we handled all records, we are done. */
1359 if (!all
&& count
== hash
->count
)
1361 } while_for_each_ftrace_rec();
1364 static void ftrace_hash_rec_disable(struct ftrace_ops
*ops
,
1367 __ftrace_hash_rec_update(ops
, filter_hash
, 0);
1370 static void ftrace_hash_rec_enable(struct ftrace_ops
*ops
,
1373 __ftrace_hash_rec_update(ops
, filter_hash
, 1);
1376 static void ftrace_free_rec(struct dyn_ftrace
*rec
)
1378 rec
->freelist
= ftrace_free_records
;
1379 ftrace_free_records
= rec
;
1380 rec
->flags
|= FTRACE_FL_FREE
;
1383 static struct dyn_ftrace
*ftrace_alloc_dyn_node(unsigned long ip
)
1385 struct dyn_ftrace
*rec
;
1387 /* First check for freed records */
1388 if (ftrace_free_records
) {
1389 rec
= ftrace_free_records
;
1391 if (unlikely(!(rec
->flags
& FTRACE_FL_FREE
))) {
1392 FTRACE_WARN_ON_ONCE(1);
1393 ftrace_free_records
= NULL
;
1397 ftrace_free_records
= rec
->freelist
;
1398 memset(rec
, 0, sizeof(*rec
));
1402 if (ftrace_pages
->index
== ENTRIES_PER_PAGE
) {
1403 if (!ftrace_pages
->next
) {
1404 /* allocate another page */
1405 ftrace_pages
->next
=
1406 (void *)get_zeroed_page(GFP_KERNEL
);
1407 if (!ftrace_pages
->next
)
1410 ftrace_pages
= ftrace_pages
->next
;
1413 return &ftrace_pages
->records
[ftrace_pages
->index
++];
1416 static struct dyn_ftrace
*
1417 ftrace_record_ip(unsigned long ip
)
1419 struct dyn_ftrace
*rec
;
1421 if (ftrace_disabled
)
1424 rec
= ftrace_alloc_dyn_node(ip
);
1429 rec
->newlist
= ftrace_new_addrs
;
1430 ftrace_new_addrs
= rec
;
1435 static void print_ip_ins(const char *fmt
, unsigned char *p
)
1439 printk(KERN_CONT
"%s", fmt
);
1441 for (i
= 0; i
< MCOUNT_INSN_SIZE
; i
++)
1442 printk(KERN_CONT
"%s%02x", i
? ":" : "", p
[i
]);
1445 static void ftrace_bug(int failed
, unsigned long ip
)
1449 FTRACE_WARN_ON_ONCE(1);
1450 pr_info("ftrace faulted on modifying ");
1454 FTRACE_WARN_ON_ONCE(1);
1455 pr_info("ftrace failed to modify ");
1457 print_ip_ins(" actual: ", (unsigned char *)ip
);
1458 printk(KERN_CONT
"\n");
1461 FTRACE_WARN_ON_ONCE(1);
1462 pr_info("ftrace faulted on writing ");
1466 FTRACE_WARN_ON_ONCE(1);
1467 pr_info("ftrace faulted on unknown error ");
1473 /* Return 1 if the address range is reserved for ftrace */
1474 int ftrace_text_reserved(void *start
, void *end
)
1476 struct dyn_ftrace
*rec
;
1477 struct ftrace_page
*pg
;
1479 do_for_each_ftrace_rec(pg
, rec
) {
1480 if (rec
->ip
<= (unsigned long)end
&&
1481 rec
->ip
+ MCOUNT_INSN_SIZE
> (unsigned long)start
)
1483 } while_for_each_ftrace_rec();
1489 __ftrace_replace_code(struct dyn_ftrace
*rec
, int enable
)
1491 unsigned long ftrace_addr
;
1492 unsigned long flag
= 0UL;
1494 ftrace_addr
= (unsigned long)FTRACE_ADDR
;
1497 * If we are enabling tracing:
1499 * If the record has a ref count, then we need to enable it
1500 * because someone is using it.
1502 * Otherwise we make sure its disabled.
1504 * If we are disabling tracing, then disable all records that
1507 if (enable
&& (rec
->flags
& ~FTRACE_FL_MASK
))
1508 flag
= FTRACE_FL_ENABLED
;
1510 /* If the state of this record hasn't changed, then do nothing */
1511 if ((rec
->flags
& FTRACE_FL_ENABLED
) == flag
)
1515 rec
->flags
|= FTRACE_FL_ENABLED
;
1516 return ftrace_make_call(rec
, ftrace_addr
);
1519 rec
->flags
&= ~FTRACE_FL_ENABLED
;
1520 return ftrace_make_nop(NULL
, rec
, ftrace_addr
);
1523 static void ftrace_replace_code(int enable
)
1525 struct dyn_ftrace
*rec
;
1526 struct ftrace_page
*pg
;
1529 if (unlikely(ftrace_disabled
))
1532 do_for_each_ftrace_rec(pg
, rec
) {
1533 /* Skip over free records */
1534 if (rec
->flags
& FTRACE_FL_FREE
)
1537 failed
= __ftrace_replace_code(rec
, enable
);
1539 ftrace_bug(failed
, rec
->ip
);
1540 /* Stop processing */
1543 } while_for_each_ftrace_rec();
1547 ftrace_code_disable(struct module
*mod
, struct dyn_ftrace
*rec
)
1554 if (unlikely(ftrace_disabled
))
1557 ret
= ftrace_make_nop(mod
, rec
, MCOUNT_ADDR
);
1559 ftrace_bug(ret
, ip
);
1566 * archs can override this function if they must do something
1567 * before the modifying code is performed.
1569 int __weak
ftrace_arch_code_modify_prepare(void)
1575 * archs can override this function if they must do something
1576 * after the modifying code is performed.
1578 int __weak
ftrace_arch_code_modify_post_process(void)
1583 static int __ftrace_modify_code(void *data
)
1585 int *command
= data
;
1587 if (*command
& FTRACE_ENABLE_CALLS
)
1588 ftrace_replace_code(1);
1589 else if (*command
& FTRACE_DISABLE_CALLS
)
1590 ftrace_replace_code(0);
1592 if (*command
& FTRACE_UPDATE_TRACE_FUNC
)
1593 ftrace_update_ftrace_func(ftrace_trace_function
);
1595 if (*command
& FTRACE_START_FUNC_RET
)
1596 ftrace_enable_ftrace_graph_caller();
1597 else if (*command
& FTRACE_STOP_FUNC_RET
)
1598 ftrace_disable_ftrace_graph_caller();
1603 static void ftrace_run_update_code(int command
)
1607 ret
= ftrace_arch_code_modify_prepare();
1608 FTRACE_WARN_ON(ret
);
1612 stop_machine(__ftrace_modify_code
, &command
, NULL
);
1614 ret
= ftrace_arch_code_modify_post_process();
1615 FTRACE_WARN_ON(ret
);
1618 static ftrace_func_t saved_ftrace_func
;
1619 static int ftrace_start_up
;
1620 static int global_start_up
;
1622 static void ftrace_startup_enable(int command
)
1624 if (saved_ftrace_func
!= ftrace_trace_function
) {
1625 saved_ftrace_func
= ftrace_trace_function
;
1626 command
|= FTRACE_UPDATE_TRACE_FUNC
;
1629 if (!command
|| !ftrace_enabled
)
1632 ftrace_run_update_code(command
);
1635 static int ftrace_startup(struct ftrace_ops
*ops
, int command
)
1637 bool hash_enable
= true;
1639 if (unlikely(ftrace_disabled
))
1643 command
|= FTRACE_ENABLE_CALLS
;
1645 /* ops marked global share the filter hashes */
1646 if (ops
->flags
& FTRACE_OPS_FL_GLOBAL
) {
1648 /* Don't update hash if global is already set */
1649 if (global_start_up
)
1650 hash_enable
= false;
1654 ops
->flags
|= FTRACE_OPS_FL_ENABLED
;
1656 ftrace_hash_rec_enable(ops
, 1);
1658 ftrace_startup_enable(command
);
1663 static void ftrace_shutdown(struct ftrace_ops
*ops
, int command
)
1665 bool hash_disable
= true;
1667 if (unlikely(ftrace_disabled
))
1672 * Just warn in case of unbalance, no need to kill ftrace, it's not
1673 * critical but the ftrace_call callers may be never nopped again after
1674 * further ftrace uses.
1676 WARN_ON_ONCE(ftrace_start_up
< 0);
1678 if (ops
->flags
& FTRACE_OPS_FL_GLOBAL
) {
1681 WARN_ON_ONCE(global_start_up
< 0);
1682 /* Don't update hash if global still has users */
1683 if (global_start_up
) {
1684 WARN_ON_ONCE(!ftrace_start_up
);
1685 hash_disable
= false;
1690 ftrace_hash_rec_disable(ops
, 1);
1692 if (ops
!= &global_ops
|| !global_start_up
)
1693 ops
->flags
&= ~FTRACE_OPS_FL_ENABLED
;
1695 if (!ftrace_start_up
)
1696 command
|= FTRACE_DISABLE_CALLS
;
1698 if (saved_ftrace_func
!= ftrace_trace_function
) {
1699 saved_ftrace_func
= ftrace_trace_function
;
1700 command
|= FTRACE_UPDATE_TRACE_FUNC
;
1703 if (!command
|| !ftrace_enabled
)
1706 ftrace_run_update_code(command
);
1709 static void ftrace_startup_sysctl(void)
1711 if (unlikely(ftrace_disabled
))
1714 /* Force update next time */
1715 saved_ftrace_func
= NULL
;
1716 /* ftrace_start_up is true if we want ftrace running */
1717 if (ftrace_start_up
)
1718 ftrace_run_update_code(FTRACE_ENABLE_CALLS
);
1721 static void ftrace_shutdown_sysctl(void)
1723 if (unlikely(ftrace_disabled
))
1726 /* ftrace_start_up is true if ftrace is running */
1727 if (ftrace_start_up
)
1728 ftrace_run_update_code(FTRACE_DISABLE_CALLS
);
1731 static cycle_t ftrace_update_time
;
1732 static unsigned long ftrace_update_cnt
;
1733 unsigned long ftrace_update_tot_cnt
;
1735 static int ftrace_update_code(struct module
*mod
)
1737 struct dyn_ftrace
*p
;
1738 cycle_t start
, stop
;
1740 start
= ftrace_now(raw_smp_processor_id());
1741 ftrace_update_cnt
= 0;
1743 while (ftrace_new_addrs
) {
1745 /* If something went wrong, bail without enabling anything */
1746 if (unlikely(ftrace_disabled
))
1749 p
= ftrace_new_addrs
;
1750 ftrace_new_addrs
= p
->newlist
;
1754 * Do the initial record conversion from mcount jump
1755 * to the NOP instructions.
1757 if (!ftrace_code_disable(mod
, p
)) {
1763 ftrace_update_cnt
++;
1766 * If the tracing is enabled, go ahead and enable the record.
1768 * The reason not to enable the record immediatelly is the
1769 * inherent check of ftrace_make_nop/ftrace_make_call for
1770 * correct previous instructions. Making first the NOP
1771 * conversion puts the module to the correct state, thus
1772 * passing the ftrace_make_call check.
1774 if (ftrace_start_up
) {
1775 int failed
= __ftrace_replace_code(p
, 1);
1777 ftrace_bug(failed
, p
->ip
);
1783 stop
= ftrace_now(raw_smp_processor_id());
1784 ftrace_update_time
= stop
- start
;
1785 ftrace_update_tot_cnt
+= ftrace_update_cnt
;
1790 static int __init
ftrace_dyn_table_alloc(unsigned long num_to_init
)
1792 struct ftrace_page
*pg
;
1796 /* allocate a few pages */
1797 ftrace_pages_start
= (void *)get_zeroed_page(GFP_KERNEL
);
1798 if (!ftrace_pages_start
)
1802 * Allocate a few more pages.
1804 * TODO: have some parser search vmlinux before
1805 * final linking to find all calls to ftrace.
1807 * a) know how many pages to allocate.
1809 * b) set up the table then.
1811 * The dynamic code is still necessary for
1815 pg
= ftrace_pages
= ftrace_pages_start
;
1817 cnt
= num_to_init
/ ENTRIES_PER_PAGE
;
1818 pr_info("ftrace: allocating %ld entries in %d pages\n",
1819 num_to_init
, cnt
+ 1);
1821 for (i
= 0; i
< cnt
; i
++) {
1822 pg
->next
= (void *)get_zeroed_page(GFP_KERNEL
);
1824 /* If we fail, we'll try later anyway */
1835 FTRACE_ITER_FILTER
= (1 << 0),
1836 FTRACE_ITER_NOTRACE
= (1 << 1),
1837 FTRACE_ITER_PRINTALL
= (1 << 2),
1838 FTRACE_ITER_HASH
= (1 << 3),
1839 FTRACE_ITER_ENABLED
= (1 << 4),
1842 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
1844 struct ftrace_iterator
{
1847 struct ftrace_page
*pg
;
1848 struct dyn_ftrace
*func
;
1849 struct ftrace_func_probe
*probe
;
1850 struct trace_parser parser
;
1851 struct ftrace_hash
*hash
;
1852 struct ftrace_ops
*ops
;
1859 t_hash_next(struct seq_file
*m
, loff_t
*pos
)
1861 struct ftrace_iterator
*iter
= m
->private;
1862 struct hlist_node
*hnd
= NULL
;
1863 struct hlist_head
*hhd
;
1869 hnd
= &iter
->probe
->node
;
1871 if (iter
->hidx
>= FTRACE_FUNC_HASHSIZE
)
1874 hhd
= &ftrace_func_hash
[iter
->hidx
];
1876 if (hlist_empty(hhd
)) {
1892 if (WARN_ON_ONCE(!hnd
))
1895 iter
->probe
= hlist_entry(hnd
, struct ftrace_func_probe
, node
);
1900 static void *t_hash_start(struct seq_file
*m
, loff_t
*pos
)
1902 struct ftrace_iterator
*iter
= m
->private;
1906 if (iter
->func_pos
> *pos
)
1910 for (l
= 0; l
<= (*pos
- iter
->func_pos
); ) {
1911 p
= t_hash_next(m
, &l
);
1918 /* Only set this if we have an item */
1919 iter
->flags
|= FTRACE_ITER_HASH
;
1925 t_hash_show(struct seq_file
*m
, struct ftrace_iterator
*iter
)
1927 struct ftrace_func_probe
*rec
;
1930 if (WARN_ON_ONCE(!rec
))
1933 if (rec
->ops
->print
)
1934 return rec
->ops
->print(m
, rec
->ip
, rec
->ops
, rec
->data
);
1936 seq_printf(m
, "%ps:%ps", (void *)rec
->ip
, (void *)rec
->ops
->func
);
1939 seq_printf(m
, ":%p", rec
->data
);
1946 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1948 struct ftrace_iterator
*iter
= m
->private;
1949 struct ftrace_ops
*ops
= &global_ops
;
1950 struct dyn_ftrace
*rec
= NULL
;
1952 if (unlikely(ftrace_disabled
))
1955 if (iter
->flags
& FTRACE_ITER_HASH
)
1956 return t_hash_next(m
, pos
);
1959 iter
->pos
= iter
->func_pos
= *pos
;
1961 if (iter
->flags
& FTRACE_ITER_PRINTALL
)
1962 return t_hash_start(m
, pos
);
1965 if (iter
->idx
>= iter
->pg
->index
) {
1966 if (iter
->pg
->next
) {
1967 iter
->pg
= iter
->pg
->next
;
1972 rec
= &iter
->pg
->records
[iter
->idx
++];
1973 if ((rec
->flags
& FTRACE_FL_FREE
) ||
1975 ((iter
->flags
& FTRACE_ITER_FILTER
) &&
1976 !(ftrace_lookup_ip(ops
->filter_hash
, rec
->ip
))) ||
1978 ((iter
->flags
& FTRACE_ITER_NOTRACE
) &&
1979 !ftrace_lookup_ip(ops
->notrace_hash
, rec
->ip
)) ||
1981 ((iter
->flags
& FTRACE_ITER_ENABLED
) &&
1982 !(rec
->flags
& ~FTRACE_FL_MASK
))) {
1990 return t_hash_start(m
, pos
);
1997 static void reset_iter_read(struct ftrace_iterator
*iter
)
2001 iter
->flags
&= ~(FTRACE_ITER_PRINTALL
& FTRACE_ITER_HASH
);
2004 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
2006 struct ftrace_iterator
*iter
= m
->private;
2007 struct ftrace_ops
*ops
= &global_ops
;
2011 mutex_lock(&ftrace_lock
);
2013 if (unlikely(ftrace_disabled
))
2017 * If an lseek was done, then reset and start from beginning.
2019 if (*pos
< iter
->pos
)
2020 reset_iter_read(iter
);
2023 * For set_ftrace_filter reading, if we have the filter
2024 * off, we can short cut and just print out that all
2025 * functions are enabled.
2027 if (iter
->flags
& FTRACE_ITER_FILTER
&& !ops
->filter_hash
->count
) {
2029 return t_hash_start(m
, pos
);
2030 iter
->flags
|= FTRACE_ITER_PRINTALL
;
2031 /* reset in case of seek/pread */
2032 iter
->flags
&= ~FTRACE_ITER_HASH
;
2036 if (iter
->flags
& FTRACE_ITER_HASH
)
2037 return t_hash_start(m
, pos
);
2040 * Unfortunately, we need to restart at ftrace_pages_start
2041 * every time we let go of the ftrace_mutex. This is because
2042 * those pointers can change without the lock.
2044 iter
->pg
= ftrace_pages_start
;
2046 for (l
= 0; l
<= *pos
; ) {
2047 p
= t_next(m
, p
, &l
);
2053 if (iter
->flags
& FTRACE_ITER_FILTER
)
2054 return t_hash_start(m
, pos
);
2062 static void t_stop(struct seq_file
*m
, void *p
)
2064 mutex_unlock(&ftrace_lock
);
2067 static int t_show(struct seq_file
*m
, void *v
)
2069 struct ftrace_iterator
*iter
= m
->private;
2070 struct dyn_ftrace
*rec
;
2072 if (iter
->flags
& FTRACE_ITER_HASH
)
2073 return t_hash_show(m
, iter
);
2075 if (iter
->flags
& FTRACE_ITER_PRINTALL
) {
2076 seq_printf(m
, "#### all functions enabled ####\n");
2085 seq_printf(m
, "%ps", (void *)rec
->ip
);
2086 if (iter
->flags
& FTRACE_ITER_ENABLED
)
2087 seq_printf(m
, " (%ld)",
2088 rec
->flags
& ~FTRACE_FL_MASK
);
2089 seq_printf(m
, "\n");
2094 static const struct seq_operations show_ftrace_seq_ops
= {
2102 ftrace_avail_open(struct inode
*inode
, struct file
*file
)
2104 struct ftrace_iterator
*iter
;
2107 if (unlikely(ftrace_disabled
))
2110 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2114 iter
->pg
= ftrace_pages_start
;
2116 ret
= seq_open(file
, &show_ftrace_seq_ops
);
2118 struct seq_file
*m
= file
->private_data
;
2129 ftrace_enabled_open(struct inode
*inode
, struct file
*file
)
2131 struct ftrace_iterator
*iter
;
2134 if (unlikely(ftrace_disabled
))
2137 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2141 iter
->pg
= ftrace_pages_start
;
2142 iter
->flags
= FTRACE_ITER_ENABLED
;
2144 ret
= seq_open(file
, &show_ftrace_seq_ops
);
2146 struct seq_file
*m
= file
->private_data
;
2156 static void ftrace_filter_reset(struct ftrace_hash
*hash
)
2158 mutex_lock(&ftrace_lock
);
2159 ftrace_hash_clear(hash
);
2160 mutex_unlock(&ftrace_lock
);
2164 ftrace_regex_open(struct ftrace_ops
*ops
, int flag
,
2165 struct inode
*inode
, struct file
*file
)
2167 struct ftrace_iterator
*iter
;
2168 struct ftrace_hash
*hash
;
2171 if (unlikely(ftrace_disabled
))
2174 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2178 if (trace_parser_get_init(&iter
->parser
, FTRACE_BUFF_MAX
)) {
2183 if (flag
& FTRACE_ITER_NOTRACE
)
2184 hash
= ops
->notrace_hash
;
2186 hash
= ops
->filter_hash
;
2191 if (file
->f_mode
& FMODE_WRITE
) {
2192 mutex_lock(&ftrace_lock
);
2193 iter
->hash
= alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
, hash
);
2194 mutex_unlock(&ftrace_lock
);
2197 trace_parser_put(&iter
->parser
);
2203 mutex_lock(&ftrace_regex_lock
);
2205 if ((file
->f_mode
& FMODE_WRITE
) &&
2206 (file
->f_flags
& O_TRUNC
))
2207 ftrace_filter_reset(iter
->hash
);
2209 if (file
->f_mode
& FMODE_READ
) {
2210 iter
->pg
= ftrace_pages_start
;
2212 ret
= seq_open(file
, &show_ftrace_seq_ops
);
2214 struct seq_file
*m
= file
->private_data
;
2218 free_ftrace_hash(iter
->hash
);
2219 trace_parser_put(&iter
->parser
);
2223 file
->private_data
= iter
;
2224 mutex_unlock(&ftrace_regex_lock
);
2230 ftrace_filter_open(struct inode
*inode
, struct file
*file
)
2232 return ftrace_regex_open(&global_ops
, FTRACE_ITER_FILTER
,
2237 ftrace_notrace_open(struct inode
*inode
, struct file
*file
)
2239 return ftrace_regex_open(&global_ops
, FTRACE_ITER_NOTRACE
,
2244 ftrace_regex_lseek(struct file
*file
, loff_t offset
, int origin
)
2248 if (file
->f_mode
& FMODE_READ
)
2249 ret
= seq_lseek(file
, offset
, origin
);
2251 file
->f_pos
= ret
= 1;
2256 static int ftrace_match(char *str
, char *regex
, int len
, int type
)
2263 if (strcmp(str
, regex
) == 0)
2266 case MATCH_FRONT_ONLY
:
2267 if (strncmp(str
, regex
, len
) == 0)
2270 case MATCH_MIDDLE_ONLY
:
2271 if (strstr(str
, regex
))
2274 case MATCH_END_ONLY
:
2276 if (slen
>= len
&& memcmp(str
+ slen
- len
, regex
, len
) == 0)
2285 enter_record(struct ftrace_hash
*hash
, struct dyn_ftrace
*rec
, int not)
2287 struct ftrace_func_entry
*entry
;
2290 entry
= ftrace_lookup_ip(hash
, rec
->ip
);
2292 /* Do nothing if it doesn't exist */
2296 free_hash_entry(hash
, entry
);
2298 /* Do nothing if it exists */
2302 ret
= add_hash_entry(hash
, rec
->ip
);
2308 ftrace_match_record(struct dyn_ftrace
*rec
, char *mod
,
2309 char *regex
, int len
, int type
)
2311 char str
[KSYM_SYMBOL_LEN
];
2314 kallsyms_lookup(rec
->ip
, NULL
, NULL
, &modname
, str
);
2317 /* module lookup requires matching the module */
2318 if (!modname
|| strcmp(modname
, mod
))
2321 /* blank search means to match all funcs in the mod */
2326 return ftrace_match(str
, regex
, len
, type
);
2330 match_records(struct ftrace_hash
*hash
, char *buff
,
2331 int len
, char *mod
, int not)
2333 unsigned search_len
= 0;
2334 struct ftrace_page
*pg
;
2335 struct dyn_ftrace
*rec
;
2336 int type
= MATCH_FULL
;
2337 char *search
= buff
;
2342 type
= filter_parse_regex(buff
, len
, &search
, ¬);
2343 search_len
= strlen(search
);
2346 mutex_lock(&ftrace_lock
);
2348 if (unlikely(ftrace_disabled
))
2351 do_for_each_ftrace_rec(pg
, rec
) {
2353 if (ftrace_match_record(rec
, mod
, search
, search_len
, type
)) {
2354 ret
= enter_record(hash
, rec
, not);
2361 } while_for_each_ftrace_rec();
2363 mutex_unlock(&ftrace_lock
);
2369 ftrace_match_records(struct ftrace_hash
*hash
, char *buff
, int len
)
2371 return match_records(hash
, buff
, len
, NULL
, 0);
2375 ftrace_match_module_records(struct ftrace_hash
*hash
, char *buff
, char *mod
)
2379 /* blank or '*' mean the same */
2380 if (strcmp(buff
, "*") == 0)
2383 /* handle the case of 'dont filter this module' */
2384 if (strcmp(buff
, "!") == 0 || strcmp(buff
, "!*") == 0) {
2389 return match_records(hash
, buff
, strlen(buff
), mod
, not);
2393 * We register the module command as a template to show others how
2394 * to register the a command as well.
2398 ftrace_mod_callback(char *func
, char *cmd
, char *param
, int enable
)
2400 struct ftrace_ops
*ops
= &global_ops
;
2401 struct ftrace_hash
*hash
;
2406 * cmd == 'mod' because we only registered this func
2407 * for the 'mod' ftrace_func_command.
2408 * But if you register one func with multiple commands,
2409 * you can tell which command was used by the cmd
2413 /* we must have a module name */
2417 mod
= strsep(¶m
, ":");
2422 hash
= ops
->filter_hash
;
2424 hash
= ops
->notrace_hash
;
2426 ret
= ftrace_match_module_records(hash
, func
, mod
);
2435 static struct ftrace_func_command ftrace_mod_cmd
= {
2437 .func
= ftrace_mod_callback
,
2440 static int __init
ftrace_mod_cmd_init(void)
2442 return register_ftrace_command(&ftrace_mod_cmd
);
2444 device_initcall(ftrace_mod_cmd_init
);
2447 function_trace_probe_call(unsigned long ip
, unsigned long parent_ip
)
2449 struct ftrace_func_probe
*entry
;
2450 struct hlist_head
*hhd
;
2451 struct hlist_node
*n
;
2454 key
= hash_long(ip
, FTRACE_HASH_BITS
);
2456 hhd
= &ftrace_func_hash
[key
];
2458 if (hlist_empty(hhd
))
2462 * Disable preemption for these calls to prevent a RCU grace
2463 * period. This syncs the hash iteration and freeing of items
2464 * on the hash. rcu_read_lock is too dangerous here.
2466 preempt_disable_notrace();
2467 hlist_for_each_entry_rcu(entry
, n
, hhd
, node
) {
2468 if (entry
->ip
== ip
)
2469 entry
->ops
->func(ip
, parent_ip
, &entry
->data
);
2471 preempt_enable_notrace();
2474 static struct ftrace_ops trace_probe_ops __read_mostly
=
2476 .func
= function_trace_probe_call
,
2479 static int ftrace_probe_registered
;
2481 static void __enable_ftrace_function_probe(void)
2486 if (ftrace_probe_registered
)
2489 for (i
= 0; i
< FTRACE_FUNC_HASHSIZE
; i
++) {
2490 struct hlist_head
*hhd
= &ftrace_func_hash
[i
];
2494 /* Nothing registered? */
2495 if (i
== FTRACE_FUNC_HASHSIZE
)
2498 ret
= __register_ftrace_function(&trace_probe_ops
);
2500 ret
= ftrace_startup(&trace_probe_ops
, 0);
2502 ftrace_probe_registered
= 1;
2505 static void __disable_ftrace_function_probe(void)
2510 if (!ftrace_probe_registered
)
2513 for (i
= 0; i
< FTRACE_FUNC_HASHSIZE
; i
++) {
2514 struct hlist_head
*hhd
= &ftrace_func_hash
[i
];
2519 /* no more funcs left */
2520 ret
= __unregister_ftrace_function(&trace_probe_ops
);
2522 ftrace_shutdown(&trace_probe_ops
, 0);
2524 ftrace_probe_registered
= 0;
2528 static void ftrace_free_entry_rcu(struct rcu_head
*rhp
)
2530 struct ftrace_func_probe
*entry
=
2531 container_of(rhp
, struct ftrace_func_probe
, rcu
);
2533 if (entry
->ops
->free
)
2534 entry
->ops
->free(&entry
->data
);
2540 register_ftrace_function_probe(char *glob
, struct ftrace_probe_ops
*ops
,
2543 struct ftrace_func_probe
*entry
;
2544 struct ftrace_page
*pg
;
2545 struct dyn_ftrace
*rec
;
2551 type
= filter_parse_regex(glob
, strlen(glob
), &search
, ¬);
2552 len
= strlen(search
);
2554 /* we do not support '!' for function probes */
2558 mutex_lock(&ftrace_lock
);
2560 if (unlikely(ftrace_disabled
))
2563 do_for_each_ftrace_rec(pg
, rec
) {
2565 if (!ftrace_match_record(rec
, NULL
, search
, len
, type
))
2568 entry
= kmalloc(sizeof(*entry
), GFP_KERNEL
);
2570 /* If we did not process any, then return error */
2581 * The caller might want to do something special
2582 * for each function we find. We call the callback
2583 * to give the caller an opportunity to do so.
2585 if (ops
->callback
) {
2586 if (ops
->callback(rec
->ip
, &entry
->data
) < 0) {
2587 /* caller does not like this func */
2594 entry
->ip
= rec
->ip
;
2596 key
= hash_long(entry
->ip
, FTRACE_HASH_BITS
);
2597 hlist_add_head_rcu(&entry
->node
, &ftrace_func_hash
[key
]);
2599 } while_for_each_ftrace_rec();
2600 __enable_ftrace_function_probe();
2603 mutex_unlock(&ftrace_lock
);
2609 PROBE_TEST_FUNC
= 1,
2614 __unregister_ftrace_function_probe(char *glob
, struct ftrace_probe_ops
*ops
,
2615 void *data
, int flags
)
2617 struct ftrace_func_probe
*entry
;
2618 struct hlist_node
*n
, *tmp
;
2619 char str
[KSYM_SYMBOL_LEN
];
2620 int type
= MATCH_FULL
;
2624 if (glob
&& (strcmp(glob
, "*") == 0 || !strlen(glob
)))
2629 type
= filter_parse_regex(glob
, strlen(glob
), &search
, ¬);
2630 len
= strlen(search
);
2632 /* we do not support '!' for function probes */
2637 mutex_lock(&ftrace_lock
);
2638 for (i
= 0; i
< FTRACE_FUNC_HASHSIZE
; i
++) {
2639 struct hlist_head
*hhd
= &ftrace_func_hash
[i
];
2641 hlist_for_each_entry_safe(entry
, n
, tmp
, hhd
, node
) {
2643 /* break up if statements for readability */
2644 if ((flags
& PROBE_TEST_FUNC
) && entry
->ops
!= ops
)
2647 if ((flags
& PROBE_TEST_DATA
) && entry
->data
!= data
)
2650 /* do this last, since it is the most expensive */
2652 kallsyms_lookup(entry
->ip
, NULL
, NULL
,
2654 if (!ftrace_match(str
, glob
, len
, type
))
2658 hlist_del(&entry
->node
);
2659 call_rcu(&entry
->rcu
, ftrace_free_entry_rcu
);
2662 __disable_ftrace_function_probe();
2663 mutex_unlock(&ftrace_lock
);
2667 unregister_ftrace_function_probe(char *glob
, struct ftrace_probe_ops
*ops
,
2670 __unregister_ftrace_function_probe(glob
, ops
, data
,
2671 PROBE_TEST_FUNC
| PROBE_TEST_DATA
);
2675 unregister_ftrace_function_probe_func(char *glob
, struct ftrace_probe_ops
*ops
)
2677 __unregister_ftrace_function_probe(glob
, ops
, NULL
, PROBE_TEST_FUNC
);
2680 void unregister_ftrace_function_probe_all(char *glob
)
2682 __unregister_ftrace_function_probe(glob
, NULL
, NULL
, 0);
2685 static LIST_HEAD(ftrace_commands
);
2686 static DEFINE_MUTEX(ftrace_cmd_mutex
);
2688 int register_ftrace_command(struct ftrace_func_command
*cmd
)
2690 struct ftrace_func_command
*p
;
2693 mutex_lock(&ftrace_cmd_mutex
);
2694 list_for_each_entry(p
, &ftrace_commands
, list
) {
2695 if (strcmp(cmd
->name
, p
->name
) == 0) {
2700 list_add(&cmd
->list
, &ftrace_commands
);
2702 mutex_unlock(&ftrace_cmd_mutex
);
2707 int unregister_ftrace_command(struct ftrace_func_command
*cmd
)
2709 struct ftrace_func_command
*p
, *n
;
2712 mutex_lock(&ftrace_cmd_mutex
);
2713 list_for_each_entry_safe(p
, n
, &ftrace_commands
, list
) {
2714 if (strcmp(cmd
->name
, p
->name
) == 0) {
2716 list_del_init(&p
->list
);
2721 mutex_unlock(&ftrace_cmd_mutex
);
2726 static int ftrace_process_regex(struct ftrace_hash
*hash
,
2727 char *buff
, int len
, int enable
)
2729 char *func
, *command
, *next
= buff
;
2730 struct ftrace_func_command
*p
;
2733 func
= strsep(&next
, ":");
2736 ret
= ftrace_match_records(hash
, func
, len
);
2746 command
= strsep(&next
, ":");
2748 mutex_lock(&ftrace_cmd_mutex
);
2749 list_for_each_entry(p
, &ftrace_commands
, list
) {
2750 if (strcmp(p
->name
, command
) == 0) {
2751 ret
= p
->func(func
, command
, next
, enable
);
2756 mutex_unlock(&ftrace_cmd_mutex
);
2762 ftrace_regex_write(struct file
*file
, const char __user
*ubuf
,
2763 size_t cnt
, loff_t
*ppos
, int enable
)
2765 struct ftrace_iterator
*iter
;
2766 struct trace_parser
*parser
;
2772 mutex_lock(&ftrace_regex_lock
);
2775 if (unlikely(ftrace_disabled
))
2778 if (file
->f_mode
& FMODE_READ
) {
2779 struct seq_file
*m
= file
->private_data
;
2782 iter
= file
->private_data
;
2784 parser
= &iter
->parser
;
2785 read
= trace_get_user(parser
, ubuf
, cnt
, ppos
);
2787 if (read
>= 0 && trace_parser_loaded(parser
) &&
2788 !trace_parser_cont(parser
)) {
2789 ret
= ftrace_process_regex(iter
->hash
, parser
->buffer
,
2790 parser
->idx
, enable
);
2791 trace_parser_clear(parser
);
2798 mutex_unlock(&ftrace_regex_lock
);
2804 ftrace_filter_write(struct file
*file
, const char __user
*ubuf
,
2805 size_t cnt
, loff_t
*ppos
)
2807 return ftrace_regex_write(file
, ubuf
, cnt
, ppos
, 1);
2811 ftrace_notrace_write(struct file
*file
, const char __user
*ubuf
,
2812 size_t cnt
, loff_t
*ppos
)
2814 return ftrace_regex_write(file
, ubuf
, cnt
, ppos
, 0);
2818 ftrace_set_regex(struct ftrace_ops
*ops
, unsigned char *buf
, int len
,
2819 int reset
, int enable
)
2821 struct ftrace_hash
**orig_hash
;
2822 struct ftrace_hash
*hash
;
2825 /* All global ops uses the global ops filters */
2826 if (ops
->flags
& FTRACE_OPS_FL_GLOBAL
)
2829 if (unlikely(ftrace_disabled
))
2833 orig_hash
= &ops
->filter_hash
;
2835 orig_hash
= &ops
->notrace_hash
;
2837 hash
= alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
, *orig_hash
);
2841 mutex_lock(&ftrace_regex_lock
);
2843 ftrace_filter_reset(hash
);
2845 ftrace_match_records(hash
, buf
, len
);
2847 mutex_lock(&ftrace_lock
);
2848 ret
= ftrace_hash_move(orig_hash
, hash
);
2849 mutex_unlock(&ftrace_lock
);
2851 mutex_unlock(&ftrace_regex_lock
);
2853 free_ftrace_hash(hash
);
2858 * ftrace_set_filter - set a function to filter on in ftrace
2859 * @ops - the ops to set the filter with
2860 * @buf - the string that holds the function filter text.
2861 * @len - the length of the string.
2862 * @reset - non zero to reset all filters before applying this filter.
2864 * Filters denote which functions should be enabled when tracing is enabled.
2865 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2867 void ftrace_set_filter(struct ftrace_ops
*ops
, unsigned char *buf
,
2870 ftrace_set_regex(ops
, buf
, len
, reset
, 1);
2872 EXPORT_SYMBOL_GPL(ftrace_set_filter
);
2875 * ftrace_set_notrace - set a function to not trace in ftrace
2876 * @ops - the ops to set the notrace filter with
2877 * @buf - the string that holds the function notrace text.
2878 * @len - the length of the string.
2879 * @reset - non zero to reset all filters before applying this filter.
2881 * Notrace Filters denote which functions should not be enabled when tracing
2882 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2885 void ftrace_set_notrace(struct ftrace_ops
*ops
, unsigned char *buf
,
2888 ftrace_set_regex(ops
, buf
, len
, reset
, 0);
2890 EXPORT_SYMBOL_GPL(ftrace_set_notrace
);
2892 * ftrace_set_filter - set a function to filter on in ftrace
2893 * @ops - the ops to set the filter with
2894 * @buf - the string that holds the function filter text.
2895 * @len - the length of the string.
2896 * @reset - non zero to reset all filters before applying this filter.
2898 * Filters denote which functions should be enabled when tracing is enabled.
2899 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2901 void ftrace_set_global_filter(unsigned char *buf
, int len
, int reset
)
2903 ftrace_set_regex(&global_ops
, buf
, len
, reset
, 1);
2905 EXPORT_SYMBOL_GPL(ftrace_set_global_filter
);
2908 * ftrace_set_notrace - set a function to not trace in ftrace
2909 * @ops - the ops to set the notrace filter with
2910 * @buf - the string that holds the function notrace text.
2911 * @len - the length of the string.
2912 * @reset - non zero to reset all filters before applying this filter.
2914 * Notrace Filters denote which functions should not be enabled when tracing
2915 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2918 void ftrace_set_global_notrace(unsigned char *buf
, int len
, int reset
)
2920 ftrace_set_regex(&global_ops
, buf
, len
, reset
, 0);
2922 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace
);
2925 * command line interface to allow users to set filters on boot up.
2927 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
2928 static char ftrace_notrace_buf
[FTRACE_FILTER_SIZE
] __initdata
;
2929 static char ftrace_filter_buf
[FTRACE_FILTER_SIZE
] __initdata
;
2931 static int __init
set_ftrace_notrace(char *str
)
2933 strncpy(ftrace_notrace_buf
, str
, FTRACE_FILTER_SIZE
);
2936 __setup("ftrace_notrace=", set_ftrace_notrace
);
2938 static int __init
set_ftrace_filter(char *str
)
2940 strncpy(ftrace_filter_buf
, str
, FTRACE_FILTER_SIZE
);
2943 __setup("ftrace_filter=", set_ftrace_filter
);
2945 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2946 static char ftrace_graph_buf
[FTRACE_FILTER_SIZE
] __initdata
;
2947 static int ftrace_set_func(unsigned long *array
, int *idx
, char *buffer
);
2949 static int __init
set_graph_function(char *str
)
2951 strlcpy(ftrace_graph_buf
, str
, FTRACE_FILTER_SIZE
);
2954 __setup("ftrace_graph_filter=", set_graph_function
);
2956 static void __init
set_ftrace_early_graph(char *buf
)
2962 func
= strsep(&buf
, ",");
2963 /* we allow only one expression at a time */
2964 ret
= ftrace_set_func(ftrace_graph_funcs
, &ftrace_graph_count
,
2967 printk(KERN_DEBUG
"ftrace: function %s not "
2968 "traceable\n", func
);
2971 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2974 set_ftrace_early_filter(struct ftrace_ops
*ops
, char *buf
, int enable
)
2979 func
= strsep(&buf
, ",");
2980 ftrace_set_regex(ops
, func
, strlen(func
), 0, enable
);
2984 static void __init
set_ftrace_early_filters(void)
2986 if (ftrace_filter_buf
[0])
2987 set_ftrace_early_filter(&global_ops
, ftrace_filter_buf
, 1);
2988 if (ftrace_notrace_buf
[0])
2989 set_ftrace_early_filter(&global_ops
, ftrace_notrace_buf
, 0);
2990 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2991 if (ftrace_graph_buf
[0])
2992 set_ftrace_early_graph(ftrace_graph_buf
);
2993 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2997 ftrace_regex_release(struct inode
*inode
, struct file
*file
)
2999 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
3000 struct ftrace_iterator
*iter
;
3001 struct ftrace_hash
**orig_hash
;
3002 struct trace_parser
*parser
;
3006 mutex_lock(&ftrace_regex_lock
);
3007 if (file
->f_mode
& FMODE_READ
) {
3010 seq_release(inode
, file
);
3012 iter
= file
->private_data
;
3014 parser
= &iter
->parser
;
3015 if (trace_parser_loaded(parser
)) {
3016 parser
->buffer
[parser
->idx
] = 0;
3017 ftrace_match_records(iter
->hash
, parser
->buffer
, parser
->idx
);
3020 trace_parser_put(parser
);
3022 if (file
->f_mode
& FMODE_WRITE
) {
3023 filter_hash
= !!(iter
->flags
& FTRACE_ITER_FILTER
);
3026 orig_hash
= &iter
->ops
->filter_hash
;
3028 orig_hash
= &iter
->ops
->notrace_hash
;
3030 mutex_lock(&ftrace_lock
);
3032 * Remove the current set, update the hash and add
3035 ftrace_hash_rec_disable(iter
->ops
, filter_hash
);
3036 ret
= ftrace_hash_move(orig_hash
, iter
->hash
);
3038 ftrace_hash_rec_enable(iter
->ops
, filter_hash
);
3039 if (iter
->ops
->flags
& FTRACE_OPS_FL_ENABLED
3041 ftrace_run_update_code(FTRACE_ENABLE_CALLS
);
3043 mutex_unlock(&ftrace_lock
);
3045 free_ftrace_hash(iter
->hash
);
3048 mutex_unlock(&ftrace_regex_lock
);
3052 static const struct file_operations ftrace_avail_fops
= {
3053 .open
= ftrace_avail_open
,
3055 .llseek
= seq_lseek
,
3056 .release
= seq_release_private
,
3059 static const struct file_operations ftrace_enabled_fops
= {
3060 .open
= ftrace_enabled_open
,
3062 .llseek
= seq_lseek
,
3063 .release
= seq_release_private
,
3066 static const struct file_operations ftrace_filter_fops
= {
3067 .open
= ftrace_filter_open
,
3069 .write
= ftrace_filter_write
,
3070 .llseek
= ftrace_regex_lseek
,
3071 .release
= ftrace_regex_release
,
3074 static const struct file_operations ftrace_notrace_fops
= {
3075 .open
= ftrace_notrace_open
,
3077 .write
= ftrace_notrace_write
,
3078 .llseek
= ftrace_regex_lseek
,
3079 .release
= ftrace_regex_release
,
3082 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3084 static DEFINE_MUTEX(graph_lock
);
3086 int ftrace_graph_count
;
3087 int ftrace_graph_filter_enabled
;
3088 unsigned long ftrace_graph_funcs
[FTRACE_GRAPH_MAX_FUNCS
] __read_mostly
;
3091 __g_next(struct seq_file
*m
, loff_t
*pos
)
3093 if (*pos
>= ftrace_graph_count
)
3095 return &ftrace_graph_funcs
[*pos
];
3099 g_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
3102 return __g_next(m
, pos
);
3105 static void *g_start(struct seq_file
*m
, loff_t
*pos
)
3107 mutex_lock(&graph_lock
);
3109 /* Nothing, tell g_show to print all functions are enabled */
3110 if (!ftrace_graph_filter_enabled
&& !*pos
)
3113 return __g_next(m
, pos
);
3116 static void g_stop(struct seq_file
*m
, void *p
)
3118 mutex_unlock(&graph_lock
);
3121 static int g_show(struct seq_file
*m
, void *v
)
3123 unsigned long *ptr
= v
;
3128 if (ptr
== (unsigned long *)1) {
3129 seq_printf(m
, "#### all functions enabled ####\n");
3133 seq_printf(m
, "%ps\n", (void *)*ptr
);
3138 static const struct seq_operations ftrace_graph_seq_ops
= {
3146 ftrace_graph_open(struct inode
*inode
, struct file
*file
)
3150 if (unlikely(ftrace_disabled
))
3153 mutex_lock(&graph_lock
);
3154 if ((file
->f_mode
& FMODE_WRITE
) &&
3155 (file
->f_flags
& O_TRUNC
)) {
3156 ftrace_graph_filter_enabled
= 0;
3157 ftrace_graph_count
= 0;
3158 memset(ftrace_graph_funcs
, 0, sizeof(ftrace_graph_funcs
));
3160 mutex_unlock(&graph_lock
);
3162 if (file
->f_mode
& FMODE_READ
)
3163 ret
= seq_open(file
, &ftrace_graph_seq_ops
);
3169 ftrace_graph_release(struct inode
*inode
, struct file
*file
)
3171 if (file
->f_mode
& FMODE_READ
)
3172 seq_release(inode
, file
);
3177 ftrace_set_func(unsigned long *array
, int *idx
, char *buffer
)
3179 struct dyn_ftrace
*rec
;
3180 struct ftrace_page
*pg
;
3189 type
= filter_parse_regex(buffer
, strlen(buffer
), &search
, ¬);
3190 if (!not && *idx
>= FTRACE_GRAPH_MAX_FUNCS
)
3193 search_len
= strlen(search
);
3195 mutex_lock(&ftrace_lock
);
3197 if (unlikely(ftrace_disabled
)) {
3198 mutex_unlock(&ftrace_lock
);
3202 do_for_each_ftrace_rec(pg
, rec
) {
3204 if (rec
->flags
& FTRACE_FL_FREE
)
3207 if (ftrace_match_record(rec
, NULL
, search
, search_len
, type
)) {
3208 /* if it is in the array */
3210 for (i
= 0; i
< *idx
; i
++) {
3211 if (array
[i
] == rec
->ip
) {
3220 array
[(*idx
)++] = rec
->ip
;
3221 if (*idx
>= FTRACE_GRAPH_MAX_FUNCS
)
3226 array
[i
] = array
[--(*idx
)];
3232 } while_for_each_ftrace_rec();
3234 mutex_unlock(&ftrace_lock
);
3239 ftrace_graph_filter_enabled
= 1;
3244 ftrace_graph_write(struct file
*file
, const char __user
*ubuf
,
3245 size_t cnt
, loff_t
*ppos
)
3247 struct trace_parser parser
;
3253 mutex_lock(&graph_lock
);
3255 if (trace_parser_get_init(&parser
, FTRACE_BUFF_MAX
)) {
3260 read
= trace_get_user(&parser
, ubuf
, cnt
, ppos
);
3262 if (read
>= 0 && trace_parser_loaded((&parser
))) {
3263 parser
.buffer
[parser
.idx
] = 0;
3265 /* we allow only one expression at a time */
3266 ret
= ftrace_set_func(ftrace_graph_funcs
, &ftrace_graph_count
,
3275 trace_parser_put(&parser
);
3277 mutex_unlock(&graph_lock
);
3282 static const struct file_operations ftrace_graph_fops
= {
3283 .open
= ftrace_graph_open
,
3285 .write
= ftrace_graph_write
,
3286 .release
= ftrace_graph_release
,
3287 .llseek
= seq_lseek
,
3289 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3291 static __init
int ftrace_init_dyn_debugfs(struct dentry
*d_tracer
)
3294 trace_create_file("available_filter_functions", 0444,
3295 d_tracer
, NULL
, &ftrace_avail_fops
);
3297 trace_create_file("enabled_functions", 0444,
3298 d_tracer
, NULL
, &ftrace_enabled_fops
);
3300 trace_create_file("set_ftrace_filter", 0644, d_tracer
,
3301 NULL
, &ftrace_filter_fops
);
3303 trace_create_file("set_ftrace_notrace", 0644, d_tracer
,
3304 NULL
, &ftrace_notrace_fops
);
3306 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3307 trace_create_file("set_graph_function", 0444, d_tracer
,
3309 &ftrace_graph_fops
);
3310 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3315 static int ftrace_process_locs(struct module
*mod
,
3316 unsigned long *start
,
3321 unsigned long flags
= 0; /* Shut up gcc */
3323 mutex_lock(&ftrace_lock
);
3326 addr
= ftrace_call_adjust(*p
++);
3328 * Some architecture linkers will pad between
3329 * the different mcount_loc sections of different
3330 * object files to satisfy alignments.
3331 * Skip any NULL pointers.
3335 ftrace_record_ip(addr
);
3339 * We only need to disable interrupts on start up
3340 * because we are modifying code that an interrupt
3341 * may execute, and the modification is not atomic.
3342 * But for modules, nothing runs the code we modify
3343 * until we are finished with it, and there's no
3344 * reason to cause large interrupt latencies while we do it.
3347 local_irq_save(flags
);
3348 ftrace_update_code(mod
);
3350 local_irq_restore(flags
);
3351 mutex_unlock(&ftrace_lock
);
3356 #ifdef CONFIG_MODULES
3357 void ftrace_release_mod(struct module
*mod
)
3359 struct dyn_ftrace
*rec
;
3360 struct ftrace_page
*pg
;
3362 mutex_lock(&ftrace_lock
);
3364 if (ftrace_disabled
)
3367 do_for_each_ftrace_rec(pg
, rec
) {
3368 if (within_module_core(rec
->ip
, mod
)) {
3370 * rec->ip is changed in ftrace_free_rec()
3371 * It should not between s and e if record was freed.
3373 FTRACE_WARN_ON(rec
->flags
& FTRACE_FL_FREE
);
3374 ftrace_free_rec(rec
);
3376 } while_for_each_ftrace_rec();
3378 mutex_unlock(&ftrace_lock
);
3381 static void ftrace_init_module(struct module
*mod
,
3382 unsigned long *start
, unsigned long *end
)
3384 if (ftrace_disabled
|| start
== end
)
3386 ftrace_process_locs(mod
, start
, end
);
3389 static int ftrace_module_notify(struct notifier_block
*self
,
3390 unsigned long val
, void *data
)
3392 struct module
*mod
= data
;
3395 case MODULE_STATE_COMING
:
3396 ftrace_init_module(mod
, mod
->ftrace_callsites
,
3397 mod
->ftrace_callsites
+
3398 mod
->num_ftrace_callsites
);
3400 case MODULE_STATE_GOING
:
3401 ftrace_release_mod(mod
);
3408 static int ftrace_module_notify(struct notifier_block
*self
,
3409 unsigned long val
, void *data
)
3413 #endif /* CONFIG_MODULES */
3415 struct notifier_block ftrace_module_nb
= {
3416 .notifier_call
= ftrace_module_notify
,
3420 extern unsigned long __start_mcount_loc
[];
3421 extern unsigned long __stop_mcount_loc
[];
3423 void __init
ftrace_init(void)
3425 unsigned long count
, addr
, flags
;
3428 /* Keep the ftrace pointer to the stub */
3429 addr
= (unsigned long)ftrace_stub
;
3431 local_irq_save(flags
);
3432 ftrace_dyn_arch_init(&addr
);
3433 local_irq_restore(flags
);
3435 /* ftrace_dyn_arch_init places the return code in addr */
3439 count
= __stop_mcount_loc
- __start_mcount_loc
;
3441 ret
= ftrace_dyn_table_alloc(count
);
3445 last_ftrace_enabled
= ftrace_enabled
= 1;
3447 ret
= ftrace_process_locs(NULL
,
3451 ret
= register_module_notifier(&ftrace_module_nb
);
3453 pr_warning("Failed to register trace ftrace module notifier\n");
3455 set_ftrace_early_filters();
3459 ftrace_disabled
= 1;
3464 static struct ftrace_ops global_ops
= {
3465 .func
= ftrace_stub
,
3468 static int __init
ftrace_nodyn_init(void)
3473 device_initcall(ftrace_nodyn_init
);
3475 static inline int ftrace_init_dyn_debugfs(struct dentry
*d_tracer
) { return 0; }
3476 static inline void ftrace_startup_enable(int command
) { }
3477 /* Keep as macros so we do not need to define the commands */
3478 # define ftrace_startup(ops, command) \
3480 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
3483 # define ftrace_shutdown(ops, command) do { } while (0)
3484 # define ftrace_startup_sysctl() do { } while (0)
3485 # define ftrace_shutdown_sysctl() do { } while (0)
3488 ftrace_ops_test(struct ftrace_ops
*ops
, unsigned long ip
)
3493 #endif /* CONFIG_DYNAMIC_FTRACE */
3496 ftrace_ops_list_func(unsigned long ip
, unsigned long parent_ip
)
3498 struct ftrace_ops
*op
;
3500 if (unlikely(trace_recursion_test(TRACE_INTERNAL_BIT
)))
3503 trace_recursion_set(TRACE_INTERNAL_BIT
);
3505 * Some of the ops may be dynamically allocated,
3506 * they must be freed after a synchronize_sched().
3508 preempt_disable_notrace();
3509 op
= rcu_dereference_raw(ftrace_ops_list
);
3510 while (op
!= &ftrace_list_end
) {
3511 if (ftrace_ops_test(op
, ip
))
3512 op
->func(ip
, parent_ip
);
3513 op
= rcu_dereference_raw(op
->next
);
3515 preempt_enable_notrace();
3516 trace_recursion_clear(TRACE_INTERNAL_BIT
);
3519 static void clear_ftrace_swapper(void)
3521 struct task_struct
*p
;
3525 for_each_online_cpu(cpu
) {
3527 clear_tsk_trace_trace(p
);
3532 static void set_ftrace_swapper(void)
3534 struct task_struct
*p
;
3538 for_each_online_cpu(cpu
) {
3540 set_tsk_trace_trace(p
);
3545 static void clear_ftrace_pid(struct pid
*pid
)
3547 struct task_struct
*p
;
3550 do_each_pid_task(pid
, PIDTYPE_PID
, p
) {
3551 clear_tsk_trace_trace(p
);
3552 } while_each_pid_task(pid
, PIDTYPE_PID
, p
);
3558 static void set_ftrace_pid(struct pid
*pid
)
3560 struct task_struct
*p
;
3563 do_each_pid_task(pid
, PIDTYPE_PID
, p
) {
3564 set_tsk_trace_trace(p
);
3565 } while_each_pid_task(pid
, PIDTYPE_PID
, p
);
3569 static void clear_ftrace_pid_task(struct pid
*pid
)
3571 if (pid
== ftrace_swapper_pid
)
3572 clear_ftrace_swapper();
3574 clear_ftrace_pid(pid
);
3577 static void set_ftrace_pid_task(struct pid
*pid
)
3579 if (pid
== ftrace_swapper_pid
)
3580 set_ftrace_swapper();
3582 set_ftrace_pid(pid
);
3585 static int ftrace_pid_add(int p
)
3588 struct ftrace_pid
*fpid
;
3591 mutex_lock(&ftrace_lock
);
3594 pid
= ftrace_swapper_pid
;
3596 pid
= find_get_pid(p
);
3603 list_for_each_entry(fpid
, &ftrace_pids
, list
)
3604 if (fpid
->pid
== pid
)
3609 fpid
= kmalloc(sizeof(*fpid
), GFP_KERNEL
);
3613 list_add(&fpid
->list
, &ftrace_pids
);
3616 set_ftrace_pid_task(pid
);
3618 ftrace_update_pid_func();
3619 ftrace_startup_enable(0);
3621 mutex_unlock(&ftrace_lock
);
3625 if (pid
!= ftrace_swapper_pid
)
3629 mutex_unlock(&ftrace_lock
);
3633 static void ftrace_pid_reset(void)
3635 struct ftrace_pid
*fpid
, *safe
;
3637 mutex_lock(&ftrace_lock
);
3638 list_for_each_entry_safe(fpid
, safe
, &ftrace_pids
, list
) {
3639 struct pid
*pid
= fpid
->pid
;
3641 clear_ftrace_pid_task(pid
);
3643 list_del(&fpid
->list
);
3647 ftrace_update_pid_func();
3648 ftrace_startup_enable(0);
3650 mutex_unlock(&ftrace_lock
);
3653 static void *fpid_start(struct seq_file
*m
, loff_t
*pos
)
3655 mutex_lock(&ftrace_lock
);
3657 if (list_empty(&ftrace_pids
) && (!*pos
))
3660 return seq_list_start(&ftrace_pids
, *pos
);
3663 static void *fpid_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
3668 return seq_list_next(v
, &ftrace_pids
, pos
);
3671 static void fpid_stop(struct seq_file
*m
, void *p
)
3673 mutex_unlock(&ftrace_lock
);
3676 static int fpid_show(struct seq_file
*m
, void *v
)
3678 const struct ftrace_pid
*fpid
= list_entry(v
, struct ftrace_pid
, list
);
3680 if (v
== (void *)1) {
3681 seq_printf(m
, "no pid\n");
3685 if (fpid
->pid
== ftrace_swapper_pid
)
3686 seq_printf(m
, "swapper tasks\n");
3688 seq_printf(m
, "%u\n", pid_vnr(fpid
->pid
));
3693 static const struct seq_operations ftrace_pid_sops
= {
3694 .start
= fpid_start
,
3701 ftrace_pid_open(struct inode
*inode
, struct file
*file
)
3705 if ((file
->f_mode
& FMODE_WRITE
) &&
3706 (file
->f_flags
& O_TRUNC
))
3709 if (file
->f_mode
& FMODE_READ
)
3710 ret
= seq_open(file
, &ftrace_pid_sops
);
3716 ftrace_pid_write(struct file
*filp
, const char __user
*ubuf
,
3717 size_t cnt
, loff_t
*ppos
)
3723 if (cnt
>= sizeof(buf
))
3726 if (copy_from_user(&buf
, ubuf
, cnt
))
3732 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
3733 * to clean the filter quietly.
3735 tmp
= strstrip(buf
);
3736 if (strlen(tmp
) == 0)
3739 ret
= strict_strtol(tmp
, 10, &val
);
3743 ret
= ftrace_pid_add(val
);
3745 return ret
? ret
: cnt
;
3749 ftrace_pid_release(struct inode
*inode
, struct file
*file
)
3751 if (file
->f_mode
& FMODE_READ
)
3752 seq_release(inode
, file
);
3757 static const struct file_operations ftrace_pid_fops
= {
3758 .open
= ftrace_pid_open
,
3759 .write
= ftrace_pid_write
,
3761 .llseek
= seq_lseek
,
3762 .release
= ftrace_pid_release
,
3765 static __init
int ftrace_init_debugfs(void)
3767 struct dentry
*d_tracer
;
3769 d_tracer
= tracing_init_dentry();
3773 ftrace_init_dyn_debugfs(d_tracer
);
3775 trace_create_file("set_ftrace_pid", 0644, d_tracer
,
3776 NULL
, &ftrace_pid_fops
);
3778 ftrace_profile_debugfs(d_tracer
);
3782 fs_initcall(ftrace_init_debugfs
);
3785 * ftrace_kill - kill ftrace
3787 * This function should be used by panic code. It stops ftrace
3788 * but in a not so nice way. If you need to simply kill ftrace
3789 * from a non-atomic section, use ftrace_kill.
3791 void ftrace_kill(void)
3793 ftrace_disabled
= 1;
3795 clear_ftrace_function();
3799 * register_ftrace_function - register a function for profiling
3800 * @ops - ops structure that holds the function for profiling.
3802 * Register a function to be called by all functions in the
3805 * Note: @ops->func and all the functions it calls must be labeled
3806 * with "notrace", otherwise it will go into a
3809 int register_ftrace_function(struct ftrace_ops
*ops
)
3813 mutex_lock(&ftrace_lock
);
3815 if (unlikely(ftrace_disabled
))
3818 ret
= __register_ftrace_function(ops
);
3820 ret
= ftrace_startup(ops
, 0);
3824 mutex_unlock(&ftrace_lock
);
3827 EXPORT_SYMBOL_GPL(register_ftrace_function
);
3830 * unregister_ftrace_function - unregister a function for profiling.
3831 * @ops - ops structure that holds the function to unregister
3833 * Unregister a function that was added to be called by ftrace profiling.
3835 int unregister_ftrace_function(struct ftrace_ops
*ops
)
3839 mutex_lock(&ftrace_lock
);
3840 ret
= __unregister_ftrace_function(ops
);
3842 ftrace_shutdown(ops
, 0);
3843 mutex_unlock(&ftrace_lock
);
3847 EXPORT_SYMBOL_GPL(unregister_ftrace_function
);
3850 ftrace_enable_sysctl(struct ctl_table
*table
, int write
,
3851 void __user
*buffer
, size_t *lenp
,
3856 mutex_lock(&ftrace_lock
);
3858 if (unlikely(ftrace_disabled
))
3861 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
3863 if (ret
|| !write
|| (last_ftrace_enabled
== !!ftrace_enabled
))
3866 last_ftrace_enabled
= !!ftrace_enabled
;
3868 if (ftrace_enabled
) {
3870 ftrace_startup_sysctl();
3872 /* we are starting ftrace again */
3873 if (ftrace_ops_list
!= &ftrace_list_end
) {
3874 if (ftrace_ops_list
->next
== &ftrace_list_end
)
3875 ftrace_trace_function
= ftrace_ops_list
->func
;
3877 ftrace_trace_function
= ftrace_ops_list_func
;
3881 /* stopping ftrace calls (just send to ftrace_stub) */
3882 ftrace_trace_function
= ftrace_stub
;
3884 ftrace_shutdown_sysctl();
3888 mutex_unlock(&ftrace_lock
);
3892 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3894 static int ftrace_graph_active
;
3895 static struct notifier_block ftrace_suspend_notifier
;
3897 int ftrace_graph_entry_stub(struct ftrace_graph_ent
*trace
)
3902 /* The callbacks that hook a function */
3903 trace_func_graph_ret_t ftrace_graph_return
=
3904 (trace_func_graph_ret_t
)ftrace_stub
;
3905 trace_func_graph_ent_t ftrace_graph_entry
= ftrace_graph_entry_stub
;
3907 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
3908 static int alloc_retstack_tasklist(struct ftrace_ret_stack
**ret_stack_list
)
3912 unsigned long flags
;
3913 int start
= 0, end
= FTRACE_RETSTACK_ALLOC_SIZE
;
3914 struct task_struct
*g
, *t
;
3916 for (i
= 0; i
< FTRACE_RETSTACK_ALLOC_SIZE
; i
++) {
3917 ret_stack_list
[i
] = kmalloc(FTRACE_RETFUNC_DEPTH
3918 * sizeof(struct ftrace_ret_stack
),
3920 if (!ret_stack_list
[i
]) {
3928 read_lock_irqsave(&tasklist_lock
, flags
);
3929 do_each_thread(g
, t
) {
3935 if (t
->ret_stack
== NULL
) {
3936 atomic_set(&t
->tracing_graph_pause
, 0);
3937 atomic_set(&t
->trace_overrun
, 0);
3938 t
->curr_ret_stack
= -1;
3939 /* Make sure the tasks see the -1 first: */
3941 t
->ret_stack
= ret_stack_list
[start
++];
3943 } while_each_thread(g
, t
);
3946 read_unlock_irqrestore(&tasklist_lock
, flags
);
3948 for (i
= start
; i
< end
; i
++)
3949 kfree(ret_stack_list
[i
]);
3954 ftrace_graph_probe_sched_switch(void *ignore
,
3955 struct task_struct
*prev
, struct task_struct
*next
)
3957 unsigned long long timestamp
;
3961 * Does the user want to count the time a function was asleep.
3962 * If so, do not update the time stamps.
3964 if (trace_flags
& TRACE_ITER_SLEEP_TIME
)
3967 timestamp
= trace_clock_local();
3969 prev
->ftrace_timestamp
= timestamp
;
3971 /* only process tasks that we timestamped */
3972 if (!next
->ftrace_timestamp
)
3976 * Update all the counters in next to make up for the
3977 * time next was sleeping.
3979 timestamp
-= next
->ftrace_timestamp
;
3981 for (index
= next
->curr_ret_stack
; index
>= 0; index
--)
3982 next
->ret_stack
[index
].calltime
+= timestamp
;
3985 /* Allocate a return stack for each task */
3986 static int start_graph_tracing(void)
3988 struct ftrace_ret_stack
**ret_stack_list
;
3991 ret_stack_list
= kmalloc(FTRACE_RETSTACK_ALLOC_SIZE
*
3992 sizeof(struct ftrace_ret_stack
*),
3995 if (!ret_stack_list
)
3998 /* The cpu_boot init_task->ret_stack will never be freed */
3999 for_each_online_cpu(cpu
) {
4000 if (!idle_task(cpu
)->ret_stack
)
4001 ftrace_graph_init_idle_task(idle_task(cpu
), cpu
);
4005 ret
= alloc_retstack_tasklist(ret_stack_list
);
4006 } while (ret
== -EAGAIN
);
4009 ret
= register_trace_sched_switch(ftrace_graph_probe_sched_switch
, NULL
);
4011 pr_info("ftrace_graph: Couldn't activate tracepoint"
4012 " probe to kernel_sched_switch\n");
4015 kfree(ret_stack_list
);
4020 * Hibernation protection.
4021 * The state of the current task is too much unstable during
4022 * suspend/restore to disk. We want to protect against that.
4025 ftrace_suspend_notifier_call(struct notifier_block
*bl
, unsigned long state
,
4029 case PM_HIBERNATION_PREPARE
:
4030 pause_graph_tracing();
4033 case PM_POST_HIBERNATION
:
4034 unpause_graph_tracing();
4040 int register_ftrace_graph(trace_func_graph_ret_t retfunc
,
4041 trace_func_graph_ent_t entryfunc
)
4045 mutex_lock(&ftrace_lock
);
4047 /* we currently allow only one tracer registered at a time */
4048 if (ftrace_graph_active
) {
4053 ftrace_suspend_notifier
.notifier_call
= ftrace_suspend_notifier_call
;
4054 register_pm_notifier(&ftrace_suspend_notifier
);
4056 ftrace_graph_active
++;
4057 ret
= start_graph_tracing();
4059 ftrace_graph_active
--;
4063 ftrace_graph_return
= retfunc
;
4064 ftrace_graph_entry
= entryfunc
;
4066 ret
= ftrace_startup(&global_ops
, FTRACE_START_FUNC_RET
);
4069 mutex_unlock(&ftrace_lock
);
4073 void unregister_ftrace_graph(void)
4075 mutex_lock(&ftrace_lock
);
4077 if (unlikely(!ftrace_graph_active
))
4080 ftrace_graph_active
--;
4081 ftrace_graph_return
= (trace_func_graph_ret_t
)ftrace_stub
;
4082 ftrace_graph_entry
= ftrace_graph_entry_stub
;
4083 ftrace_shutdown(&global_ops
, FTRACE_STOP_FUNC_RET
);
4084 unregister_pm_notifier(&ftrace_suspend_notifier
);
4085 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch
, NULL
);
4088 mutex_unlock(&ftrace_lock
);
4091 static DEFINE_PER_CPU(struct ftrace_ret_stack
*, idle_ret_stack
);
4094 graph_init_task(struct task_struct
*t
, struct ftrace_ret_stack
*ret_stack
)
4096 atomic_set(&t
->tracing_graph_pause
, 0);
4097 atomic_set(&t
->trace_overrun
, 0);
4098 t
->ftrace_timestamp
= 0;
4099 /* make curr_ret_stack visible before we add the ret_stack */
4101 t
->ret_stack
= ret_stack
;
4105 * Allocate a return stack for the idle task. May be the first
4106 * time through, or it may be done by CPU hotplug online.
4108 void ftrace_graph_init_idle_task(struct task_struct
*t
, int cpu
)
4110 t
->curr_ret_stack
= -1;
4112 * The idle task has no parent, it either has its own
4113 * stack or no stack at all.
4116 WARN_ON(t
->ret_stack
!= per_cpu(idle_ret_stack
, cpu
));
4118 if (ftrace_graph_active
) {
4119 struct ftrace_ret_stack
*ret_stack
;
4121 ret_stack
= per_cpu(idle_ret_stack
, cpu
);
4123 ret_stack
= kmalloc(FTRACE_RETFUNC_DEPTH
4124 * sizeof(struct ftrace_ret_stack
),
4128 per_cpu(idle_ret_stack
, cpu
) = ret_stack
;
4130 graph_init_task(t
, ret_stack
);
4134 /* Allocate a return stack for newly created task */
4135 void ftrace_graph_init_task(struct task_struct
*t
)
4137 /* Make sure we do not use the parent ret_stack */
4138 t
->ret_stack
= NULL
;
4139 t
->curr_ret_stack
= -1;
4141 if (ftrace_graph_active
) {
4142 struct ftrace_ret_stack
*ret_stack
;
4144 ret_stack
= kmalloc(FTRACE_RETFUNC_DEPTH
4145 * sizeof(struct ftrace_ret_stack
),
4149 graph_init_task(t
, ret_stack
);
4153 void ftrace_graph_exit_task(struct task_struct
*t
)
4155 struct ftrace_ret_stack
*ret_stack
= t
->ret_stack
;
4157 t
->ret_stack
= NULL
;
4158 /* NULL must become visible to IRQs before we free it: */
4164 void ftrace_graph_stop(void)