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/kprobes.h>
26 #include <linux/ftrace.h>
27 #include <linux/sysctl.h>
28 #include <linux/ctype.h>
29 #include <linux/list.h>
30 #include <linux/hash.h>
32 #include <trace/events/sched.h>
34 #include <asm/ftrace.h>
35 #include <asm/setup.h>
37 #include "trace_output.h"
38 #include "trace_stat.h"
40 #define FTRACE_WARN_ON(cond) \
46 #define FTRACE_WARN_ON_ONCE(cond) \
48 if (WARN_ON_ONCE(cond)) \
52 /* hash bits for specific function selection */
53 #define FTRACE_HASH_BITS 7
54 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
56 /* ftrace_enabled is a method to turn ftrace on or off */
57 int ftrace_enabled __read_mostly
;
58 static int last_ftrace_enabled
;
60 /* Quick disabling of function tracer. */
61 int function_trace_stop
;
64 * ftrace_disabled is set when an anomaly is discovered.
65 * ftrace_disabled is much stronger than ftrace_enabled.
67 static int ftrace_disabled __read_mostly
;
69 static DEFINE_MUTEX(ftrace_lock
);
71 static struct ftrace_ops ftrace_list_end __read_mostly
=
76 static struct ftrace_ops
*ftrace_list __read_mostly
= &ftrace_list_end
;
77 ftrace_func_t ftrace_trace_function __read_mostly
= ftrace_stub
;
78 ftrace_func_t __ftrace_trace_function __read_mostly
= ftrace_stub
;
79 ftrace_func_t ftrace_pid_function __read_mostly
= ftrace_stub
;
81 static void ftrace_list_func(unsigned long ip
, unsigned long parent_ip
)
83 struct ftrace_ops
*op
= ftrace_list
;
85 /* in case someone actually ports this to alpha! */
86 read_barrier_depends();
88 while (op
!= &ftrace_list_end
) {
90 read_barrier_depends();
91 op
->func(ip
, parent_ip
);
96 static void ftrace_pid_func(unsigned long ip
, unsigned long parent_ip
)
98 if (!test_tsk_trace_trace(current
))
101 ftrace_pid_function(ip
, parent_ip
);
104 static void set_ftrace_pid_function(ftrace_func_t func
)
106 /* do not set ftrace_pid_function to itself! */
107 if (func
!= ftrace_pid_func
)
108 ftrace_pid_function
= func
;
112 * clear_ftrace_function - reset the ftrace function
114 * This NULLs the ftrace function and in essence stops
115 * tracing. There may be lag
117 void clear_ftrace_function(void)
119 ftrace_trace_function
= ftrace_stub
;
120 __ftrace_trace_function
= ftrace_stub
;
121 ftrace_pid_function
= ftrace_stub
;
124 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
126 * For those archs that do not test ftrace_trace_stop in their
127 * mcount call site, we need to do it from C.
129 static void ftrace_test_stop_func(unsigned long ip
, unsigned long parent_ip
)
131 if (function_trace_stop
)
134 __ftrace_trace_function(ip
, parent_ip
);
138 static int __register_ftrace_function(struct ftrace_ops
*ops
)
140 ops
->next
= ftrace_list
;
142 * We are entering ops into the ftrace_list but another
143 * CPU might be walking that list. We need to make sure
144 * the ops->next pointer is valid before another CPU sees
145 * the ops pointer included into the ftrace_list.
150 if (ftrace_enabled
) {
153 if (ops
->next
== &ftrace_list_end
)
156 func
= ftrace_list_func
;
158 if (ftrace_pid_trace
) {
159 set_ftrace_pid_function(func
);
160 func
= ftrace_pid_func
;
164 * For one func, simply call it directly.
165 * For more than one func, call the chain.
167 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
168 ftrace_trace_function
= func
;
170 __ftrace_trace_function
= func
;
171 ftrace_trace_function
= ftrace_test_stop_func
;
178 static int __unregister_ftrace_function(struct ftrace_ops
*ops
)
180 struct ftrace_ops
**p
;
183 * If we are removing the last function, then simply point
184 * to the ftrace_stub.
186 if (ftrace_list
== ops
&& ops
->next
== &ftrace_list_end
) {
187 ftrace_trace_function
= ftrace_stub
;
188 ftrace_list
= &ftrace_list_end
;
192 for (p
= &ftrace_list
; *p
!= &ftrace_list_end
; p
= &(*p
)->next
)
201 if (ftrace_enabled
) {
202 /* If we only have one func left, then call that directly */
203 if (ftrace_list
->next
== &ftrace_list_end
) {
204 ftrace_func_t func
= ftrace_list
->func
;
206 if (ftrace_pid_trace
) {
207 set_ftrace_pid_function(func
);
208 func
= ftrace_pid_func
;
210 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
211 ftrace_trace_function
= func
;
213 __ftrace_trace_function
= func
;
221 static void ftrace_update_pid_func(void)
225 if (ftrace_trace_function
== ftrace_stub
)
228 func
= ftrace_trace_function
;
230 if (ftrace_pid_trace
) {
231 set_ftrace_pid_function(func
);
232 func
= ftrace_pid_func
;
234 if (func
== ftrace_pid_func
)
235 func
= ftrace_pid_function
;
238 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
239 ftrace_trace_function
= func
;
241 __ftrace_trace_function
= func
;
245 #ifdef CONFIG_FUNCTION_PROFILER
246 struct ftrace_profile
{
247 struct hlist_node node
;
249 unsigned long counter
;
250 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
251 unsigned long long time
;
255 struct ftrace_profile_page
{
256 struct ftrace_profile_page
*next
;
258 struct ftrace_profile records
[];
261 struct ftrace_profile_stat
{
263 struct hlist_head
*hash
;
264 struct ftrace_profile_page
*pages
;
265 struct ftrace_profile_page
*start
;
266 struct tracer_stat stat
;
269 #define PROFILE_RECORDS_SIZE \
270 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
272 #define PROFILES_PER_PAGE \
273 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
275 static int ftrace_profile_bits __read_mostly
;
276 static int ftrace_profile_enabled __read_mostly
;
278 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
279 static DEFINE_MUTEX(ftrace_profile_lock
);
281 static DEFINE_PER_CPU(struct ftrace_profile_stat
, ftrace_profile_stats
);
283 #define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
286 function_stat_next(void *v
, int idx
)
288 struct ftrace_profile
*rec
= v
;
289 struct ftrace_profile_page
*pg
;
291 pg
= (struct ftrace_profile_page
*)((unsigned long)rec
& PAGE_MASK
);
297 if ((void *)rec
>= (void *)&pg
->records
[pg
->index
]) {
301 rec
= &pg
->records
[0];
309 static void *function_stat_start(struct tracer_stat
*trace
)
311 struct ftrace_profile_stat
*stat
=
312 container_of(trace
, struct ftrace_profile_stat
, stat
);
314 if (!stat
|| !stat
->start
)
317 return function_stat_next(&stat
->start
->records
[0], 0);
320 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
321 /* function graph compares on total time */
322 static int function_stat_cmp(void *p1
, void *p2
)
324 struct ftrace_profile
*a
= p1
;
325 struct ftrace_profile
*b
= p2
;
327 if (a
->time
< b
->time
)
329 if (a
->time
> b
->time
)
335 /* not function graph compares against hits */
336 static int function_stat_cmp(void *p1
, void *p2
)
338 struct ftrace_profile
*a
= p1
;
339 struct ftrace_profile
*b
= p2
;
341 if (a
->counter
< b
->counter
)
343 if (a
->counter
> b
->counter
)
350 static int function_stat_headers(struct seq_file
*m
)
352 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
353 seq_printf(m
, " Function "
358 seq_printf(m
, " Function Hit\n"
364 static int function_stat_show(struct seq_file
*m
, void *v
)
366 struct ftrace_profile
*rec
= v
;
367 char str
[KSYM_SYMBOL_LEN
];
368 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
369 static DEFINE_MUTEX(mutex
);
370 static struct trace_seq s
;
371 unsigned long long avg
;
374 kallsyms_lookup(rec
->ip
, NULL
, NULL
, NULL
, str
);
375 seq_printf(m
, " %-30.30s %10lu", str
, rec
->counter
);
377 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
380 do_div(avg
, rec
->counter
);
384 trace_print_graph_duration(rec
->time
, &s
);
385 trace_seq_puts(&s
, " ");
386 trace_print_graph_duration(avg
, &s
);
387 trace_print_seq(m
, &s
);
388 mutex_unlock(&mutex
);
395 static void ftrace_profile_reset(struct ftrace_profile_stat
*stat
)
397 struct ftrace_profile_page
*pg
;
399 pg
= stat
->pages
= stat
->start
;
402 memset(pg
->records
, 0, PROFILE_RECORDS_SIZE
);
407 memset(stat
->hash
, 0,
408 FTRACE_PROFILE_HASH_SIZE
* sizeof(struct hlist_head
));
411 int ftrace_profile_pages_init(struct ftrace_profile_stat
*stat
)
413 struct ftrace_profile_page
*pg
;
418 /* If we already allocated, do nothing */
422 stat
->pages
= (void *)get_zeroed_page(GFP_KERNEL
);
426 #ifdef CONFIG_DYNAMIC_FTRACE
427 functions
= ftrace_update_tot_cnt
;
430 * We do not know the number of functions that exist because
431 * dynamic tracing is what counts them. With past experience
432 * we have around 20K functions. That should be more than enough.
433 * It is highly unlikely we will execute every function in
439 pg
= stat
->start
= stat
->pages
;
441 pages
= DIV_ROUND_UP(functions
, PROFILES_PER_PAGE
);
443 for (i
= 0; i
< pages
; i
++) {
444 pg
->next
= (void *)get_zeroed_page(GFP_KERNEL
);
455 unsigned long tmp
= (unsigned long)pg
;
461 free_page((unsigned long)stat
->pages
);
468 static int ftrace_profile_init_cpu(int cpu
)
470 struct ftrace_profile_stat
*stat
;
473 stat
= &per_cpu(ftrace_profile_stats
, cpu
);
476 /* If the profile is already created, simply reset it */
477 ftrace_profile_reset(stat
);
482 * We are profiling all functions, but usually only a few thousand
483 * functions are hit. We'll make a hash of 1024 items.
485 size
= FTRACE_PROFILE_HASH_SIZE
;
487 stat
->hash
= kzalloc(sizeof(struct hlist_head
) * size
, GFP_KERNEL
);
492 if (!ftrace_profile_bits
) {
495 for (; size
; size
>>= 1)
496 ftrace_profile_bits
++;
499 /* Preallocate the function profiling pages */
500 if (ftrace_profile_pages_init(stat
) < 0) {
509 static int ftrace_profile_init(void)
514 for_each_online_cpu(cpu
) {
515 ret
= ftrace_profile_init_cpu(cpu
);
523 /* interrupts must be disabled */
524 static struct ftrace_profile
*
525 ftrace_find_profiled_func(struct ftrace_profile_stat
*stat
, unsigned long ip
)
527 struct ftrace_profile
*rec
;
528 struct hlist_head
*hhd
;
529 struct hlist_node
*n
;
532 key
= hash_long(ip
, ftrace_profile_bits
);
533 hhd
= &stat
->hash
[key
];
535 if (hlist_empty(hhd
))
538 hlist_for_each_entry_rcu(rec
, n
, hhd
, node
) {
546 static void ftrace_add_profile(struct ftrace_profile_stat
*stat
,
547 struct ftrace_profile
*rec
)
551 key
= hash_long(rec
->ip
, ftrace_profile_bits
);
552 hlist_add_head_rcu(&rec
->node
, &stat
->hash
[key
]);
556 * The memory is already allocated, this simply finds a new record to use.
558 static struct ftrace_profile
*
559 ftrace_profile_alloc(struct ftrace_profile_stat
*stat
, unsigned long ip
)
561 struct ftrace_profile
*rec
= NULL
;
563 /* prevent recursion (from NMIs) */
564 if (atomic_inc_return(&stat
->disabled
) != 1)
568 * Try to find the function again since an NMI
569 * could have added it
571 rec
= ftrace_find_profiled_func(stat
, ip
);
575 if (stat
->pages
->index
== PROFILES_PER_PAGE
) {
576 if (!stat
->pages
->next
)
578 stat
->pages
= stat
->pages
->next
;
581 rec
= &stat
->pages
->records
[stat
->pages
->index
++];
583 ftrace_add_profile(stat
, rec
);
586 atomic_dec(&stat
->disabled
);
592 function_profile_call(unsigned long ip
, unsigned long parent_ip
)
594 struct ftrace_profile_stat
*stat
;
595 struct ftrace_profile
*rec
;
598 if (!ftrace_profile_enabled
)
601 local_irq_save(flags
);
603 stat
= &__get_cpu_var(ftrace_profile_stats
);
604 if (!stat
->hash
|| !ftrace_profile_enabled
)
607 rec
= ftrace_find_profiled_func(stat
, ip
);
609 rec
= ftrace_profile_alloc(stat
, ip
);
616 local_irq_restore(flags
);
619 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
620 static int profile_graph_entry(struct ftrace_graph_ent
*trace
)
622 function_profile_call(trace
->func
, 0);
626 static void profile_graph_return(struct ftrace_graph_ret
*trace
)
628 struct ftrace_profile_stat
*stat
;
629 unsigned long long calltime
;
630 struct ftrace_profile
*rec
;
633 local_irq_save(flags
);
634 stat
= &__get_cpu_var(ftrace_profile_stats
);
635 if (!stat
->hash
|| !ftrace_profile_enabled
)
638 calltime
= trace
->rettime
- trace
->calltime
;
640 if (!(trace_flags
& TRACE_ITER_GRAPH_TIME
)) {
643 index
= trace
->depth
;
645 /* Append this call time to the parent time to subtract */
647 current
->ret_stack
[index
- 1].subtime
+= calltime
;
649 if (current
->ret_stack
[index
].subtime
< calltime
)
650 calltime
-= current
->ret_stack
[index
].subtime
;
655 rec
= ftrace_find_profiled_func(stat
, trace
->func
);
657 rec
->time
+= calltime
;
660 local_irq_restore(flags
);
663 static int register_ftrace_profiler(void)
665 return register_ftrace_graph(&profile_graph_return
,
666 &profile_graph_entry
);
669 static void unregister_ftrace_profiler(void)
671 unregister_ftrace_graph();
674 static struct ftrace_ops ftrace_profile_ops __read_mostly
=
676 .func
= function_profile_call
,
679 static int register_ftrace_profiler(void)
681 return register_ftrace_function(&ftrace_profile_ops
);
684 static void unregister_ftrace_profiler(void)
686 unregister_ftrace_function(&ftrace_profile_ops
);
688 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
691 ftrace_profile_write(struct file
*filp
, const char __user
*ubuf
,
692 size_t cnt
, loff_t
*ppos
)
695 char buf
[64]; /* big enough to hold a number */
698 if (cnt
>= sizeof(buf
))
701 if (copy_from_user(&buf
, ubuf
, cnt
))
706 ret
= strict_strtoul(buf
, 10, &val
);
712 mutex_lock(&ftrace_profile_lock
);
713 if (ftrace_profile_enabled
^ val
) {
715 ret
= ftrace_profile_init();
721 ret
= register_ftrace_profiler();
726 ftrace_profile_enabled
= 1;
728 ftrace_profile_enabled
= 0;
730 * unregister_ftrace_profiler calls stop_machine
731 * so this acts like an synchronize_sched.
733 unregister_ftrace_profiler();
737 mutex_unlock(&ftrace_profile_lock
);
745 ftrace_profile_read(struct file
*filp
, char __user
*ubuf
,
746 size_t cnt
, loff_t
*ppos
)
748 char buf
[64]; /* big enough to hold a number */
751 r
= sprintf(buf
, "%u\n", ftrace_profile_enabled
);
752 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
755 static const struct file_operations ftrace_profile_fops
= {
756 .open
= tracing_open_generic
,
757 .read
= ftrace_profile_read
,
758 .write
= ftrace_profile_write
,
761 /* used to initialize the real stat files */
762 static struct tracer_stat function_stats __initdata
= {
764 .stat_start
= function_stat_start
,
765 .stat_next
= function_stat_next
,
766 .stat_cmp
= function_stat_cmp
,
767 .stat_headers
= function_stat_headers
,
768 .stat_show
= function_stat_show
771 static __init
void ftrace_profile_debugfs(struct dentry
*d_tracer
)
773 struct ftrace_profile_stat
*stat
;
774 struct dentry
*entry
;
779 for_each_possible_cpu(cpu
) {
780 stat
= &per_cpu(ftrace_profile_stats
, cpu
);
782 /* allocate enough for function name + cpu number */
783 name
= kmalloc(32, GFP_KERNEL
);
786 * The files created are permanent, if something happens
787 * we still do not free memory.
790 "Could not allocate stat file for cpu %d\n",
794 stat
->stat
= function_stats
;
795 snprintf(name
, 32, "function%d", cpu
);
796 stat
->stat
.name
= name
;
797 ret
= register_stat_tracer(&stat
->stat
);
800 "Could not register function stat for cpu %d\n",
807 entry
= debugfs_create_file("function_profile_enabled", 0644,
808 d_tracer
, NULL
, &ftrace_profile_fops
);
810 pr_warning("Could not create debugfs "
811 "'function_profile_enabled' entry\n");
814 #else /* CONFIG_FUNCTION_PROFILER */
815 static __init
void ftrace_profile_debugfs(struct dentry
*d_tracer
)
818 #endif /* CONFIG_FUNCTION_PROFILER */
820 /* set when tracing only a pid */
821 struct pid
*ftrace_pid_trace
;
822 static struct pid
* const ftrace_swapper_pid
= &init_struct_pid
;
824 #ifdef CONFIG_DYNAMIC_FTRACE
826 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
827 # error Dynamic ftrace depends on MCOUNT_RECORD
830 static struct hlist_head ftrace_func_hash
[FTRACE_FUNC_HASHSIZE
] __read_mostly
;
832 struct ftrace_func_probe
{
833 struct hlist_node node
;
834 struct ftrace_probe_ops
*ops
;
842 FTRACE_ENABLE_CALLS
= (1 << 0),
843 FTRACE_DISABLE_CALLS
= (1 << 1),
844 FTRACE_UPDATE_TRACE_FUNC
= (1 << 2),
845 FTRACE_ENABLE_MCOUNT
= (1 << 3),
846 FTRACE_DISABLE_MCOUNT
= (1 << 4),
847 FTRACE_START_FUNC_RET
= (1 << 5),
848 FTRACE_STOP_FUNC_RET
= (1 << 6),
851 static int ftrace_filtered
;
853 static struct dyn_ftrace
*ftrace_new_addrs
;
855 static DEFINE_MUTEX(ftrace_regex_lock
);
858 struct ftrace_page
*next
;
860 struct dyn_ftrace records
[];
863 #define ENTRIES_PER_PAGE \
864 ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
866 /* estimate from running different kernels */
867 #define NR_TO_INIT 10000
869 static struct ftrace_page
*ftrace_pages_start
;
870 static struct ftrace_page
*ftrace_pages
;
872 static struct dyn_ftrace
*ftrace_free_records
;
875 * This is a double for. Do not use 'break' to break out of the loop,
876 * you must use a goto.
878 #define do_for_each_ftrace_rec(pg, rec) \
879 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
881 for (_____i = 0; _____i < pg->index; _____i++) { \
882 rec = &pg->records[_____i];
884 #define while_for_each_ftrace_rec() \
888 #ifdef CONFIG_KPROBES
890 static int frozen_record_count
;
892 static inline void freeze_record(struct dyn_ftrace
*rec
)
894 if (!(rec
->flags
& FTRACE_FL_FROZEN
)) {
895 rec
->flags
|= FTRACE_FL_FROZEN
;
896 frozen_record_count
++;
900 static inline void unfreeze_record(struct dyn_ftrace
*rec
)
902 if (rec
->flags
& FTRACE_FL_FROZEN
) {
903 rec
->flags
&= ~FTRACE_FL_FROZEN
;
904 frozen_record_count
--;
908 static inline int record_frozen(struct dyn_ftrace
*rec
)
910 return rec
->flags
& FTRACE_FL_FROZEN
;
913 # define freeze_record(rec) ({ 0; })
914 # define unfreeze_record(rec) ({ 0; })
915 # define record_frozen(rec) ({ 0; })
916 #endif /* CONFIG_KPROBES */
918 static void ftrace_free_rec(struct dyn_ftrace
*rec
)
920 rec
->freelist
= ftrace_free_records
;
921 ftrace_free_records
= rec
;
922 rec
->flags
|= FTRACE_FL_FREE
;
925 static struct dyn_ftrace
*ftrace_alloc_dyn_node(unsigned long ip
)
927 struct dyn_ftrace
*rec
;
929 /* First check for freed records */
930 if (ftrace_free_records
) {
931 rec
= ftrace_free_records
;
933 if (unlikely(!(rec
->flags
& FTRACE_FL_FREE
))) {
934 FTRACE_WARN_ON_ONCE(1);
935 ftrace_free_records
= NULL
;
939 ftrace_free_records
= rec
->freelist
;
940 memset(rec
, 0, sizeof(*rec
));
944 if (ftrace_pages
->index
== ENTRIES_PER_PAGE
) {
945 if (!ftrace_pages
->next
) {
946 /* allocate another page */
948 (void *)get_zeroed_page(GFP_KERNEL
);
949 if (!ftrace_pages
->next
)
952 ftrace_pages
= ftrace_pages
->next
;
955 return &ftrace_pages
->records
[ftrace_pages
->index
++];
958 static struct dyn_ftrace
*
959 ftrace_record_ip(unsigned long ip
)
961 struct dyn_ftrace
*rec
;
966 rec
= ftrace_alloc_dyn_node(ip
);
971 rec
->newlist
= ftrace_new_addrs
;
972 ftrace_new_addrs
= rec
;
977 static void print_ip_ins(const char *fmt
, unsigned char *p
)
981 printk(KERN_CONT
"%s", fmt
);
983 for (i
= 0; i
< MCOUNT_INSN_SIZE
; i
++)
984 printk(KERN_CONT
"%s%02x", i
? ":" : "", p
[i
]);
987 static void ftrace_bug(int failed
, unsigned long ip
)
991 FTRACE_WARN_ON_ONCE(1);
992 pr_info("ftrace faulted on modifying ");
996 FTRACE_WARN_ON_ONCE(1);
997 pr_info("ftrace failed to modify ");
999 print_ip_ins(" actual: ", (unsigned char *)ip
);
1000 printk(KERN_CONT
"\n");
1003 FTRACE_WARN_ON_ONCE(1);
1004 pr_info("ftrace faulted on writing ");
1008 FTRACE_WARN_ON_ONCE(1);
1009 pr_info("ftrace faulted on unknown error ");
1016 __ftrace_replace_code(struct dyn_ftrace
*rec
, int enable
)
1018 unsigned long ftrace_addr
;
1019 unsigned long ip
, fl
;
1021 ftrace_addr
= (unsigned long)FTRACE_ADDR
;
1026 * If this record is not to be traced and
1027 * it is not enabled then do nothing.
1029 * If this record is not to be traced and
1030 * it is enabled then disable it.
1033 if (rec
->flags
& FTRACE_FL_NOTRACE
) {
1034 if (rec
->flags
& FTRACE_FL_ENABLED
)
1035 rec
->flags
&= ~FTRACE_FL_ENABLED
;
1039 } else if (ftrace_filtered
&& enable
) {
1044 fl
= rec
->flags
& (FTRACE_FL_FILTER
| FTRACE_FL_ENABLED
);
1046 /* Record is filtered and enabled, do nothing */
1047 if (fl
== (FTRACE_FL_FILTER
| FTRACE_FL_ENABLED
))
1050 /* Record is not filtered or enabled, do nothing */
1054 /* Record is not filtered but enabled, disable it */
1055 if (fl
== FTRACE_FL_ENABLED
)
1056 rec
->flags
&= ~FTRACE_FL_ENABLED
;
1058 /* Otherwise record is filtered but not enabled, enable it */
1059 rec
->flags
|= FTRACE_FL_ENABLED
;
1061 /* Disable or not filtered */
1064 /* if record is enabled, do nothing */
1065 if (rec
->flags
& FTRACE_FL_ENABLED
)
1068 rec
->flags
|= FTRACE_FL_ENABLED
;
1072 /* if record is not enabled, do nothing */
1073 if (!(rec
->flags
& FTRACE_FL_ENABLED
))
1076 rec
->flags
&= ~FTRACE_FL_ENABLED
;
1080 if (rec
->flags
& FTRACE_FL_ENABLED
)
1081 return ftrace_make_call(rec
, ftrace_addr
);
1083 return ftrace_make_nop(NULL
, rec
, ftrace_addr
);
1086 static void ftrace_replace_code(int enable
)
1088 struct dyn_ftrace
*rec
;
1089 struct ftrace_page
*pg
;
1092 do_for_each_ftrace_rec(pg
, rec
) {
1094 * Skip over free records, records that have
1095 * failed and not converted.
1097 if (rec
->flags
& FTRACE_FL_FREE
||
1098 rec
->flags
& FTRACE_FL_FAILED
||
1099 !(rec
->flags
& FTRACE_FL_CONVERTED
))
1102 /* ignore updates to this record's mcount site */
1103 if (get_kprobe((void *)rec
->ip
)) {
1107 unfreeze_record(rec
);
1110 failed
= __ftrace_replace_code(rec
, enable
);
1112 rec
->flags
|= FTRACE_FL_FAILED
;
1113 if ((system_state
== SYSTEM_BOOTING
) ||
1114 !core_kernel_text(rec
->ip
)) {
1115 ftrace_free_rec(rec
);
1117 ftrace_bug(failed
, rec
->ip
);
1118 /* Stop processing */
1122 } while_for_each_ftrace_rec();
1126 ftrace_code_disable(struct module
*mod
, struct dyn_ftrace
*rec
)
1133 ret
= ftrace_make_nop(mod
, rec
, MCOUNT_ADDR
);
1135 ftrace_bug(ret
, ip
);
1136 rec
->flags
|= FTRACE_FL_FAILED
;
1143 * archs can override this function if they must do something
1144 * before the modifying code is performed.
1146 int __weak
ftrace_arch_code_modify_prepare(void)
1152 * archs can override this function if they must do something
1153 * after the modifying code is performed.
1155 int __weak
ftrace_arch_code_modify_post_process(void)
1160 static int __ftrace_modify_code(void *data
)
1162 int *command
= data
;
1164 if (*command
& FTRACE_ENABLE_CALLS
)
1165 ftrace_replace_code(1);
1166 else if (*command
& FTRACE_DISABLE_CALLS
)
1167 ftrace_replace_code(0);
1169 if (*command
& FTRACE_UPDATE_TRACE_FUNC
)
1170 ftrace_update_ftrace_func(ftrace_trace_function
);
1172 if (*command
& FTRACE_START_FUNC_RET
)
1173 ftrace_enable_ftrace_graph_caller();
1174 else if (*command
& FTRACE_STOP_FUNC_RET
)
1175 ftrace_disable_ftrace_graph_caller();
1180 static void ftrace_run_update_code(int command
)
1184 ret
= ftrace_arch_code_modify_prepare();
1185 FTRACE_WARN_ON(ret
);
1189 stop_machine(__ftrace_modify_code
, &command
, NULL
);
1191 ret
= ftrace_arch_code_modify_post_process();
1192 FTRACE_WARN_ON(ret
);
1195 static ftrace_func_t saved_ftrace_func
;
1196 static int ftrace_start_up
;
1198 static void ftrace_startup_enable(int command
)
1200 if (saved_ftrace_func
!= ftrace_trace_function
) {
1201 saved_ftrace_func
= ftrace_trace_function
;
1202 command
|= FTRACE_UPDATE_TRACE_FUNC
;
1205 if (!command
|| !ftrace_enabled
)
1208 ftrace_run_update_code(command
);
1211 static void ftrace_startup(int command
)
1213 if (unlikely(ftrace_disabled
))
1217 command
|= FTRACE_ENABLE_CALLS
;
1219 ftrace_startup_enable(command
);
1222 static void ftrace_shutdown(int command
)
1224 if (unlikely(ftrace_disabled
))
1229 * Just warn in case of unbalance, no need to kill ftrace, it's not
1230 * critical but the ftrace_call callers may be never nopped again after
1231 * further ftrace uses.
1233 WARN_ON_ONCE(ftrace_start_up
< 0);
1235 if (!ftrace_start_up
)
1236 command
|= FTRACE_DISABLE_CALLS
;
1238 if (saved_ftrace_func
!= ftrace_trace_function
) {
1239 saved_ftrace_func
= ftrace_trace_function
;
1240 command
|= FTRACE_UPDATE_TRACE_FUNC
;
1243 if (!command
|| !ftrace_enabled
)
1246 ftrace_run_update_code(command
);
1249 static void ftrace_startup_sysctl(void)
1251 int command
= FTRACE_ENABLE_MCOUNT
;
1253 if (unlikely(ftrace_disabled
))
1256 /* Force update next time */
1257 saved_ftrace_func
= NULL
;
1258 /* ftrace_start_up is true if we want ftrace running */
1259 if (ftrace_start_up
)
1260 command
|= FTRACE_ENABLE_CALLS
;
1262 ftrace_run_update_code(command
);
1265 static void ftrace_shutdown_sysctl(void)
1267 int command
= FTRACE_DISABLE_MCOUNT
;
1269 if (unlikely(ftrace_disabled
))
1272 /* ftrace_start_up is true if ftrace is running */
1273 if (ftrace_start_up
)
1274 command
|= FTRACE_DISABLE_CALLS
;
1276 ftrace_run_update_code(command
);
1279 static cycle_t ftrace_update_time
;
1280 static unsigned long ftrace_update_cnt
;
1281 unsigned long ftrace_update_tot_cnt
;
1283 static int ftrace_update_code(struct module
*mod
)
1285 struct dyn_ftrace
*p
;
1286 cycle_t start
, stop
;
1288 start
= ftrace_now(raw_smp_processor_id());
1289 ftrace_update_cnt
= 0;
1291 while (ftrace_new_addrs
) {
1293 /* If something went wrong, bail without enabling anything */
1294 if (unlikely(ftrace_disabled
))
1297 p
= ftrace_new_addrs
;
1298 ftrace_new_addrs
= p
->newlist
;
1301 /* convert record (i.e, patch mcount-call with NOP) */
1302 if (ftrace_code_disable(mod
, p
)) {
1303 p
->flags
|= FTRACE_FL_CONVERTED
;
1304 ftrace_update_cnt
++;
1309 stop
= ftrace_now(raw_smp_processor_id());
1310 ftrace_update_time
= stop
- start
;
1311 ftrace_update_tot_cnt
+= ftrace_update_cnt
;
1316 static int __init
ftrace_dyn_table_alloc(unsigned long num_to_init
)
1318 struct ftrace_page
*pg
;
1322 /* allocate a few pages */
1323 ftrace_pages_start
= (void *)get_zeroed_page(GFP_KERNEL
);
1324 if (!ftrace_pages_start
)
1328 * Allocate a few more pages.
1330 * TODO: have some parser search vmlinux before
1331 * final linking to find all calls to ftrace.
1333 * a) know how many pages to allocate.
1335 * b) set up the table then.
1337 * The dynamic code is still necessary for
1341 pg
= ftrace_pages
= ftrace_pages_start
;
1343 cnt
= num_to_init
/ ENTRIES_PER_PAGE
;
1344 pr_info("ftrace: allocating %ld entries in %d pages\n",
1345 num_to_init
, cnt
+ 1);
1347 for (i
= 0; i
< cnt
; i
++) {
1348 pg
->next
= (void *)get_zeroed_page(GFP_KERNEL
);
1350 /* If we fail, we'll try later anyway */
1361 FTRACE_ITER_FILTER
= (1 << 0),
1362 FTRACE_ITER_CONT
= (1 << 1),
1363 FTRACE_ITER_NOTRACE
= (1 << 2),
1364 FTRACE_ITER_FAILURES
= (1 << 3),
1365 FTRACE_ITER_PRINTALL
= (1 << 4),
1366 FTRACE_ITER_HASH
= (1 << 5),
1369 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
1371 struct ftrace_iterator
{
1372 struct ftrace_page
*pg
;
1376 unsigned char buffer
[FTRACE_BUFF_MAX
+1];
1377 unsigned buffer_idx
;
1382 t_hash_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1384 struct ftrace_iterator
*iter
= m
->private;
1385 struct hlist_node
*hnd
= v
;
1386 struct hlist_head
*hhd
;
1388 WARN_ON(!(iter
->flags
& FTRACE_ITER_HASH
));
1393 if (iter
->hidx
>= FTRACE_FUNC_HASHSIZE
)
1396 hhd
= &ftrace_func_hash
[iter
->hidx
];
1398 if (hlist_empty(hhd
)) {
1417 static void *t_hash_start(struct seq_file
*m
, loff_t
*pos
)
1419 struct ftrace_iterator
*iter
= m
->private;
1423 if (!(iter
->flags
& FTRACE_ITER_HASH
))
1426 iter
->flags
|= FTRACE_ITER_HASH
;
1429 for (l
= 0; l
<= *pos
; ) {
1430 p
= t_hash_next(m
, p
, &l
);
1437 static int t_hash_show(struct seq_file
*m
, void *v
)
1439 struct ftrace_func_probe
*rec
;
1440 struct hlist_node
*hnd
= v
;
1441 char str
[KSYM_SYMBOL_LEN
];
1443 rec
= hlist_entry(hnd
, struct ftrace_func_probe
, node
);
1445 if (rec
->ops
->print
)
1446 return rec
->ops
->print(m
, rec
->ip
, rec
->ops
, rec
->data
);
1448 kallsyms_lookup(rec
->ip
, NULL
, NULL
, NULL
, str
);
1449 seq_printf(m
, "%s:", str
);
1451 kallsyms_lookup((unsigned long)rec
->ops
->func
, NULL
, NULL
, NULL
, str
);
1452 seq_printf(m
, "%s", str
);
1455 seq_printf(m
, ":%p", rec
->data
);
1462 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1464 struct ftrace_iterator
*iter
= m
->private;
1465 struct dyn_ftrace
*rec
= NULL
;
1467 if (iter
->flags
& FTRACE_ITER_HASH
)
1468 return t_hash_next(m
, v
, pos
);
1472 if (iter
->flags
& FTRACE_ITER_PRINTALL
)
1476 if (iter
->idx
>= iter
->pg
->index
) {
1477 if (iter
->pg
->next
) {
1478 iter
->pg
= iter
->pg
->next
;
1483 rec
= &iter
->pg
->records
[iter
->idx
++];
1484 if ((rec
->flags
& FTRACE_FL_FREE
) ||
1486 (!(iter
->flags
& FTRACE_ITER_FAILURES
) &&
1487 (rec
->flags
& FTRACE_FL_FAILED
)) ||
1489 ((iter
->flags
& FTRACE_ITER_FAILURES
) &&
1490 !(rec
->flags
& FTRACE_FL_FAILED
)) ||
1492 ((iter
->flags
& FTRACE_ITER_FILTER
) &&
1493 !(rec
->flags
& FTRACE_FL_FILTER
)) ||
1495 ((iter
->flags
& FTRACE_ITER_NOTRACE
) &&
1496 !(rec
->flags
& FTRACE_FL_NOTRACE
))) {
1505 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
1507 struct ftrace_iterator
*iter
= m
->private;
1511 mutex_lock(&ftrace_lock
);
1513 * For set_ftrace_filter reading, if we have the filter
1514 * off, we can short cut and just print out that all
1515 * functions are enabled.
1517 if (iter
->flags
& FTRACE_ITER_FILTER
&& !ftrace_filtered
) {
1519 return t_hash_start(m
, pos
);
1520 iter
->flags
|= FTRACE_ITER_PRINTALL
;
1524 if (iter
->flags
& FTRACE_ITER_HASH
)
1525 return t_hash_start(m
, pos
);
1527 iter
->pg
= ftrace_pages_start
;
1529 for (l
= 0; l
<= *pos
; ) {
1530 p
= t_next(m
, p
, &l
);
1535 if (!p
&& iter
->flags
& FTRACE_ITER_FILTER
)
1536 return t_hash_start(m
, pos
);
1541 static void t_stop(struct seq_file
*m
, void *p
)
1543 mutex_unlock(&ftrace_lock
);
1546 static int t_show(struct seq_file
*m
, void *v
)
1548 struct ftrace_iterator
*iter
= m
->private;
1549 struct dyn_ftrace
*rec
= v
;
1550 char str
[KSYM_SYMBOL_LEN
];
1552 if (iter
->flags
& FTRACE_ITER_HASH
)
1553 return t_hash_show(m
, v
);
1555 if (iter
->flags
& FTRACE_ITER_PRINTALL
) {
1556 seq_printf(m
, "#### all functions enabled ####\n");
1563 kallsyms_lookup(rec
->ip
, NULL
, NULL
, NULL
, str
);
1565 seq_printf(m
, "%s\n", str
);
1570 static struct seq_operations show_ftrace_seq_ops
= {
1578 ftrace_avail_open(struct inode
*inode
, struct file
*file
)
1580 struct ftrace_iterator
*iter
;
1583 if (unlikely(ftrace_disabled
))
1586 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
1590 iter
->pg
= ftrace_pages_start
;
1592 ret
= seq_open(file
, &show_ftrace_seq_ops
);
1594 struct seq_file
*m
= file
->private_data
;
1604 int ftrace_avail_release(struct inode
*inode
, struct file
*file
)
1606 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
1607 struct ftrace_iterator
*iter
= m
->private;
1609 seq_release(inode
, file
);
1616 ftrace_failures_open(struct inode
*inode
, struct file
*file
)
1620 struct ftrace_iterator
*iter
;
1622 ret
= ftrace_avail_open(inode
, file
);
1624 m
= (struct seq_file
*)file
->private_data
;
1625 iter
= (struct ftrace_iterator
*)m
->private;
1626 iter
->flags
= FTRACE_ITER_FAILURES
;
1633 static void ftrace_filter_reset(int enable
)
1635 struct ftrace_page
*pg
;
1636 struct dyn_ftrace
*rec
;
1637 unsigned long type
= enable
? FTRACE_FL_FILTER
: FTRACE_FL_NOTRACE
;
1639 mutex_lock(&ftrace_lock
);
1641 ftrace_filtered
= 0;
1642 do_for_each_ftrace_rec(pg
, rec
) {
1643 if (rec
->flags
& FTRACE_FL_FAILED
)
1645 rec
->flags
&= ~type
;
1646 } while_for_each_ftrace_rec();
1647 mutex_unlock(&ftrace_lock
);
1651 ftrace_regex_open(struct inode
*inode
, struct file
*file
, int enable
)
1653 struct ftrace_iterator
*iter
;
1656 if (unlikely(ftrace_disabled
))
1659 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
1663 mutex_lock(&ftrace_regex_lock
);
1664 if ((file
->f_mode
& FMODE_WRITE
) &&
1665 (file
->f_flags
& O_TRUNC
))
1666 ftrace_filter_reset(enable
);
1668 if (file
->f_mode
& FMODE_READ
) {
1669 iter
->pg
= ftrace_pages_start
;
1670 iter
->flags
= enable
? FTRACE_ITER_FILTER
:
1671 FTRACE_ITER_NOTRACE
;
1673 ret
= seq_open(file
, &show_ftrace_seq_ops
);
1675 struct seq_file
*m
= file
->private_data
;
1680 file
->private_data
= iter
;
1681 mutex_unlock(&ftrace_regex_lock
);
1687 ftrace_filter_open(struct inode
*inode
, struct file
*file
)
1689 return ftrace_regex_open(inode
, file
, 1);
1693 ftrace_notrace_open(struct inode
*inode
, struct file
*file
)
1695 return ftrace_regex_open(inode
, file
, 0);
1699 ftrace_regex_lseek(struct file
*file
, loff_t offset
, int origin
)
1703 if (file
->f_mode
& FMODE_READ
)
1704 ret
= seq_lseek(file
, offset
, origin
);
1706 file
->f_pos
= ret
= 1;
1719 * (static function - no need for kernel doc)
1721 * Pass in a buffer containing a glob and this function will
1722 * set search to point to the search part of the buffer and
1723 * return the type of search it is (see enum above).
1724 * This does modify buff.
1726 * Returns enum type.
1727 * search returns the pointer to use for comparison.
1728 * not returns 1 if buff started with a '!'
1732 ftrace_setup_glob(char *buff
, int len
, char **search
, int *not)
1734 int type
= MATCH_FULL
;
1737 if (buff
[0] == '!') {
1746 for (i
= 0; i
< len
; i
++) {
1747 if (buff
[i
] == '*') {
1750 type
= MATCH_END_ONLY
;
1752 if (type
== MATCH_END_ONLY
)
1753 type
= MATCH_MIDDLE_ONLY
;
1755 type
= MATCH_FRONT_ONLY
;
1765 static int ftrace_match(char *str
, char *regex
, int len
, int type
)
1772 if (strcmp(str
, regex
) == 0)
1775 case MATCH_FRONT_ONLY
:
1776 if (strncmp(str
, regex
, len
) == 0)
1779 case MATCH_MIDDLE_ONLY
:
1780 if (strstr(str
, regex
))
1783 case MATCH_END_ONLY
:
1784 ptr
= strstr(str
, regex
);
1785 if (ptr
&& (ptr
[len
] == 0))
1794 ftrace_match_record(struct dyn_ftrace
*rec
, char *regex
, int len
, int type
)
1796 char str
[KSYM_SYMBOL_LEN
];
1798 kallsyms_lookup(rec
->ip
, NULL
, NULL
, NULL
, str
);
1799 return ftrace_match(str
, regex
, len
, type
);
1802 static void ftrace_match_records(char *buff
, int len
, int enable
)
1804 unsigned int search_len
;
1805 struct ftrace_page
*pg
;
1806 struct dyn_ftrace
*rec
;
1812 flag
= enable
? FTRACE_FL_FILTER
: FTRACE_FL_NOTRACE
;
1813 type
= ftrace_setup_glob(buff
, len
, &search
, ¬);
1815 search_len
= strlen(search
);
1817 mutex_lock(&ftrace_lock
);
1818 do_for_each_ftrace_rec(pg
, rec
) {
1820 if (rec
->flags
& FTRACE_FL_FAILED
)
1823 if (ftrace_match_record(rec
, search
, search_len
, type
)) {
1825 rec
->flags
&= ~flag
;
1830 * Only enable filtering if we have a function that
1833 if (enable
&& (rec
->flags
& FTRACE_FL_FILTER
))
1834 ftrace_filtered
= 1;
1835 } while_for_each_ftrace_rec();
1836 mutex_unlock(&ftrace_lock
);
1840 ftrace_match_module_record(struct dyn_ftrace
*rec
, char *mod
,
1841 char *regex
, int len
, int type
)
1843 char str
[KSYM_SYMBOL_LEN
];
1846 kallsyms_lookup(rec
->ip
, NULL
, NULL
, &modname
, str
);
1848 if (!modname
|| strcmp(modname
, mod
))
1851 /* blank search means to match all funcs in the mod */
1853 return ftrace_match(str
, regex
, len
, type
);
1858 static void ftrace_match_module_records(char *buff
, char *mod
, int enable
)
1860 unsigned search_len
= 0;
1861 struct ftrace_page
*pg
;
1862 struct dyn_ftrace
*rec
;
1863 int type
= MATCH_FULL
;
1864 char *search
= buff
;
1868 flag
= enable
? FTRACE_FL_FILTER
: FTRACE_FL_NOTRACE
;
1870 /* blank or '*' mean the same */
1871 if (strcmp(buff
, "*") == 0)
1874 /* handle the case of 'dont filter this module' */
1875 if (strcmp(buff
, "!") == 0 || strcmp(buff
, "!*") == 0) {
1881 type
= ftrace_setup_glob(buff
, strlen(buff
), &search
, ¬);
1882 search_len
= strlen(search
);
1885 mutex_lock(&ftrace_lock
);
1886 do_for_each_ftrace_rec(pg
, rec
) {
1888 if (rec
->flags
& FTRACE_FL_FAILED
)
1891 if (ftrace_match_module_record(rec
, mod
,
1892 search
, search_len
, type
)) {
1894 rec
->flags
&= ~flag
;
1898 if (enable
&& (rec
->flags
& FTRACE_FL_FILTER
))
1899 ftrace_filtered
= 1;
1901 } while_for_each_ftrace_rec();
1902 mutex_unlock(&ftrace_lock
);
1906 * We register the module command as a template to show others how
1907 * to register the a command as well.
1911 ftrace_mod_callback(char *func
, char *cmd
, char *param
, int enable
)
1916 * cmd == 'mod' because we only registered this func
1917 * for the 'mod' ftrace_func_command.
1918 * But if you register one func with multiple commands,
1919 * you can tell which command was used by the cmd
1923 /* we must have a module name */
1927 mod
= strsep(¶m
, ":");
1931 ftrace_match_module_records(func
, mod
, enable
);
1935 static struct ftrace_func_command ftrace_mod_cmd
= {
1937 .func
= ftrace_mod_callback
,
1940 static int __init
ftrace_mod_cmd_init(void)
1942 return register_ftrace_command(&ftrace_mod_cmd
);
1944 device_initcall(ftrace_mod_cmd_init
);
1947 function_trace_probe_call(unsigned long ip
, unsigned long parent_ip
)
1949 struct ftrace_func_probe
*entry
;
1950 struct hlist_head
*hhd
;
1951 struct hlist_node
*n
;
1955 key
= hash_long(ip
, FTRACE_HASH_BITS
);
1957 hhd
= &ftrace_func_hash
[key
];
1959 if (hlist_empty(hhd
))
1963 * Disable preemption for these calls to prevent a RCU grace
1964 * period. This syncs the hash iteration and freeing of items
1965 * on the hash. rcu_read_lock is too dangerous here.
1967 resched
= ftrace_preempt_disable();
1968 hlist_for_each_entry_rcu(entry
, n
, hhd
, node
) {
1969 if (entry
->ip
== ip
)
1970 entry
->ops
->func(ip
, parent_ip
, &entry
->data
);
1972 ftrace_preempt_enable(resched
);
1975 static struct ftrace_ops trace_probe_ops __read_mostly
=
1977 .func
= function_trace_probe_call
,
1980 static int ftrace_probe_registered
;
1982 static void __enable_ftrace_function_probe(void)
1986 if (ftrace_probe_registered
)
1989 for (i
= 0; i
< FTRACE_FUNC_HASHSIZE
; i
++) {
1990 struct hlist_head
*hhd
= &ftrace_func_hash
[i
];
1994 /* Nothing registered? */
1995 if (i
== FTRACE_FUNC_HASHSIZE
)
1998 __register_ftrace_function(&trace_probe_ops
);
2000 ftrace_probe_registered
= 1;
2003 static void __disable_ftrace_function_probe(void)
2007 if (!ftrace_probe_registered
)
2010 for (i
= 0; i
< FTRACE_FUNC_HASHSIZE
; i
++) {
2011 struct hlist_head
*hhd
= &ftrace_func_hash
[i
];
2016 /* no more funcs left */
2017 __unregister_ftrace_function(&trace_probe_ops
);
2019 ftrace_probe_registered
= 0;
2023 static void ftrace_free_entry_rcu(struct rcu_head
*rhp
)
2025 struct ftrace_func_probe
*entry
=
2026 container_of(rhp
, struct ftrace_func_probe
, rcu
);
2028 if (entry
->ops
->free
)
2029 entry
->ops
->free(&entry
->data
);
2035 register_ftrace_function_probe(char *glob
, struct ftrace_probe_ops
*ops
,
2038 struct ftrace_func_probe
*entry
;
2039 struct ftrace_page
*pg
;
2040 struct dyn_ftrace
*rec
;
2046 type
= ftrace_setup_glob(glob
, strlen(glob
), &search
, ¬);
2047 len
= strlen(search
);
2049 /* we do not support '!' for function probes */
2053 mutex_lock(&ftrace_lock
);
2054 do_for_each_ftrace_rec(pg
, rec
) {
2056 if (rec
->flags
& FTRACE_FL_FAILED
)
2059 if (!ftrace_match_record(rec
, search
, len
, type
))
2062 entry
= kmalloc(sizeof(*entry
), GFP_KERNEL
);
2064 /* If we did not process any, then return error */
2075 * The caller might want to do something special
2076 * for each function we find. We call the callback
2077 * to give the caller an opportunity to do so.
2079 if (ops
->callback
) {
2080 if (ops
->callback(rec
->ip
, &entry
->data
) < 0) {
2081 /* caller does not like this func */
2088 entry
->ip
= rec
->ip
;
2090 key
= hash_long(entry
->ip
, FTRACE_HASH_BITS
);
2091 hlist_add_head_rcu(&entry
->node
, &ftrace_func_hash
[key
]);
2093 } while_for_each_ftrace_rec();
2094 __enable_ftrace_function_probe();
2097 mutex_unlock(&ftrace_lock
);
2103 PROBE_TEST_FUNC
= 1,
2108 __unregister_ftrace_function_probe(char *glob
, struct ftrace_probe_ops
*ops
,
2109 void *data
, int flags
)
2111 struct ftrace_func_probe
*entry
;
2112 struct hlist_node
*n
, *tmp
;
2113 char str
[KSYM_SYMBOL_LEN
];
2114 int type
= MATCH_FULL
;
2118 if (glob
&& (strcmp(glob
, "*") || !strlen(glob
)))
2123 type
= ftrace_setup_glob(glob
, strlen(glob
), &search
, ¬);
2124 len
= strlen(search
);
2126 /* we do not support '!' for function probes */
2131 mutex_lock(&ftrace_lock
);
2132 for (i
= 0; i
< FTRACE_FUNC_HASHSIZE
; i
++) {
2133 struct hlist_head
*hhd
= &ftrace_func_hash
[i
];
2135 hlist_for_each_entry_safe(entry
, n
, tmp
, hhd
, node
) {
2137 /* break up if statements for readability */
2138 if ((flags
& PROBE_TEST_FUNC
) && entry
->ops
!= ops
)
2141 if ((flags
& PROBE_TEST_DATA
) && entry
->data
!= data
)
2144 /* do this last, since it is the most expensive */
2146 kallsyms_lookup(entry
->ip
, NULL
, NULL
,
2148 if (!ftrace_match(str
, glob
, len
, type
))
2152 hlist_del(&entry
->node
);
2153 call_rcu(&entry
->rcu
, ftrace_free_entry_rcu
);
2156 __disable_ftrace_function_probe();
2157 mutex_unlock(&ftrace_lock
);
2161 unregister_ftrace_function_probe(char *glob
, struct ftrace_probe_ops
*ops
,
2164 __unregister_ftrace_function_probe(glob
, ops
, data
,
2165 PROBE_TEST_FUNC
| PROBE_TEST_DATA
);
2169 unregister_ftrace_function_probe_func(char *glob
, struct ftrace_probe_ops
*ops
)
2171 __unregister_ftrace_function_probe(glob
, ops
, NULL
, PROBE_TEST_FUNC
);
2174 void unregister_ftrace_function_probe_all(char *glob
)
2176 __unregister_ftrace_function_probe(glob
, NULL
, NULL
, 0);
2179 static LIST_HEAD(ftrace_commands
);
2180 static DEFINE_MUTEX(ftrace_cmd_mutex
);
2182 int register_ftrace_command(struct ftrace_func_command
*cmd
)
2184 struct ftrace_func_command
*p
;
2187 mutex_lock(&ftrace_cmd_mutex
);
2188 list_for_each_entry(p
, &ftrace_commands
, list
) {
2189 if (strcmp(cmd
->name
, p
->name
) == 0) {
2194 list_add(&cmd
->list
, &ftrace_commands
);
2196 mutex_unlock(&ftrace_cmd_mutex
);
2201 int unregister_ftrace_command(struct ftrace_func_command
*cmd
)
2203 struct ftrace_func_command
*p
, *n
;
2206 mutex_lock(&ftrace_cmd_mutex
);
2207 list_for_each_entry_safe(p
, n
, &ftrace_commands
, list
) {
2208 if (strcmp(cmd
->name
, p
->name
) == 0) {
2210 list_del_init(&p
->list
);
2215 mutex_unlock(&ftrace_cmd_mutex
);
2220 static int ftrace_process_regex(char *buff
, int len
, int enable
)
2222 char *func
, *command
, *next
= buff
;
2223 struct ftrace_func_command
*p
;
2226 func
= strsep(&next
, ":");
2229 ftrace_match_records(func
, len
, enable
);
2235 command
= strsep(&next
, ":");
2237 mutex_lock(&ftrace_cmd_mutex
);
2238 list_for_each_entry(p
, &ftrace_commands
, list
) {
2239 if (strcmp(p
->name
, command
) == 0) {
2240 ret
= p
->func(func
, command
, next
, enable
);
2245 mutex_unlock(&ftrace_cmd_mutex
);
2251 ftrace_regex_write(struct file
*file
, const char __user
*ubuf
,
2252 size_t cnt
, loff_t
*ppos
, int enable
)
2254 struct ftrace_iterator
*iter
;
2259 if (!cnt
|| cnt
< 0)
2262 mutex_lock(&ftrace_regex_lock
);
2264 if (file
->f_mode
& FMODE_READ
) {
2265 struct seq_file
*m
= file
->private_data
;
2268 iter
= file
->private_data
;
2271 iter
->flags
&= ~FTRACE_ITER_CONT
;
2272 iter
->buffer_idx
= 0;
2275 ret
= get_user(ch
, ubuf
++);
2281 if (!(iter
->flags
& ~FTRACE_ITER_CONT
)) {
2282 /* skip white space */
2283 while (cnt
&& isspace(ch
)) {
2284 ret
= get_user(ch
, ubuf
++);
2292 file
->f_pos
+= read
;
2297 iter
->buffer_idx
= 0;
2300 while (cnt
&& !isspace(ch
)) {
2301 if (iter
->buffer_idx
< FTRACE_BUFF_MAX
)
2302 iter
->buffer
[iter
->buffer_idx
++] = ch
;
2307 ret
= get_user(ch
, ubuf
++);
2316 iter
->buffer
[iter
->buffer_idx
] = 0;
2317 ret
= ftrace_process_regex(iter
->buffer
,
2318 iter
->buffer_idx
, enable
);
2321 iter
->buffer_idx
= 0;
2323 iter
->flags
|= FTRACE_ITER_CONT
;
2326 file
->f_pos
+= read
;
2330 mutex_unlock(&ftrace_regex_lock
);
2336 ftrace_filter_write(struct file
*file
, const char __user
*ubuf
,
2337 size_t cnt
, loff_t
*ppos
)
2339 return ftrace_regex_write(file
, ubuf
, cnt
, ppos
, 1);
2343 ftrace_notrace_write(struct file
*file
, const char __user
*ubuf
,
2344 size_t cnt
, loff_t
*ppos
)
2346 return ftrace_regex_write(file
, ubuf
, cnt
, ppos
, 0);
2350 ftrace_set_regex(unsigned char *buf
, int len
, int reset
, int enable
)
2352 if (unlikely(ftrace_disabled
))
2355 mutex_lock(&ftrace_regex_lock
);
2357 ftrace_filter_reset(enable
);
2359 ftrace_match_records(buf
, len
, enable
);
2360 mutex_unlock(&ftrace_regex_lock
);
2364 * ftrace_set_filter - set a function to filter on in ftrace
2365 * @buf - the string that holds the function filter text.
2366 * @len - the length of the string.
2367 * @reset - non zero to reset all filters before applying this filter.
2369 * Filters denote which functions should be enabled when tracing is enabled.
2370 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2372 void ftrace_set_filter(unsigned char *buf
, int len
, int reset
)
2374 ftrace_set_regex(buf
, len
, reset
, 1);
2378 * ftrace_set_notrace - set a function to not trace in ftrace
2379 * @buf - the string that holds the function notrace text.
2380 * @len - the length of the string.
2381 * @reset - non zero to reset all filters before applying this filter.
2383 * Notrace Filters denote which functions should not be enabled when tracing
2384 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2387 void ftrace_set_notrace(unsigned char *buf
, int len
, int reset
)
2389 ftrace_set_regex(buf
, len
, reset
, 0);
2393 * command line interface to allow users to set filters on boot up.
2395 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
2396 static char ftrace_notrace_buf
[FTRACE_FILTER_SIZE
] __initdata
;
2397 static char ftrace_filter_buf
[FTRACE_FILTER_SIZE
] __initdata
;
2399 static int __init
set_ftrace_notrace(char *str
)
2401 strncpy(ftrace_notrace_buf
, str
, FTRACE_FILTER_SIZE
);
2404 __setup("ftrace_notrace=", set_ftrace_notrace
);
2406 static int __init
set_ftrace_filter(char *str
)
2408 strncpy(ftrace_filter_buf
, str
, FTRACE_FILTER_SIZE
);
2411 __setup("ftrace_filter=", set_ftrace_filter
);
2413 static void __init
set_ftrace_early_filter(char *buf
, int enable
)
2418 func
= strsep(&buf
, ",");
2419 ftrace_set_regex(func
, strlen(func
), 0, enable
);
2423 static void __init
set_ftrace_early_filters(void)
2425 if (ftrace_filter_buf
[0])
2426 set_ftrace_early_filter(ftrace_filter_buf
, 1);
2427 if (ftrace_notrace_buf
[0])
2428 set_ftrace_early_filter(ftrace_notrace_buf
, 0);
2432 ftrace_regex_release(struct inode
*inode
, struct file
*file
, int enable
)
2434 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
2435 struct ftrace_iterator
*iter
;
2437 mutex_lock(&ftrace_regex_lock
);
2438 if (file
->f_mode
& FMODE_READ
) {
2441 seq_release(inode
, file
);
2443 iter
= file
->private_data
;
2445 if (iter
->buffer_idx
) {
2447 iter
->buffer
[iter
->buffer_idx
] = 0;
2448 ftrace_match_records(iter
->buffer
, iter
->buffer_idx
, enable
);
2451 mutex_lock(&ftrace_lock
);
2452 if (ftrace_start_up
&& ftrace_enabled
)
2453 ftrace_run_update_code(FTRACE_ENABLE_CALLS
);
2454 mutex_unlock(&ftrace_lock
);
2457 mutex_unlock(&ftrace_regex_lock
);
2462 ftrace_filter_release(struct inode
*inode
, struct file
*file
)
2464 return ftrace_regex_release(inode
, file
, 1);
2468 ftrace_notrace_release(struct inode
*inode
, struct file
*file
)
2470 return ftrace_regex_release(inode
, file
, 0);
2473 static const struct file_operations ftrace_avail_fops
= {
2474 .open
= ftrace_avail_open
,
2476 .llseek
= seq_lseek
,
2477 .release
= ftrace_avail_release
,
2480 static const struct file_operations ftrace_failures_fops
= {
2481 .open
= ftrace_failures_open
,
2483 .llseek
= seq_lseek
,
2484 .release
= ftrace_avail_release
,
2487 static const struct file_operations ftrace_filter_fops
= {
2488 .open
= ftrace_filter_open
,
2490 .write
= ftrace_filter_write
,
2491 .llseek
= ftrace_regex_lseek
,
2492 .release
= ftrace_filter_release
,
2495 static const struct file_operations ftrace_notrace_fops
= {
2496 .open
= ftrace_notrace_open
,
2498 .write
= ftrace_notrace_write
,
2499 .llseek
= ftrace_regex_lseek
,
2500 .release
= ftrace_notrace_release
,
2503 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2505 static DEFINE_MUTEX(graph_lock
);
2507 int ftrace_graph_count
;
2508 unsigned long ftrace_graph_funcs
[FTRACE_GRAPH_MAX_FUNCS
] __read_mostly
;
2511 __g_next(struct seq_file
*m
, loff_t
*pos
)
2513 unsigned long *array
= m
->private;
2515 if (*pos
>= ftrace_graph_count
)
2517 return &array
[*pos
];
2521 g_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
2524 return __g_next(m
, pos
);
2527 static void *g_start(struct seq_file
*m
, loff_t
*pos
)
2529 mutex_lock(&graph_lock
);
2531 /* Nothing, tell g_show to print all functions are enabled */
2532 if (!ftrace_graph_count
&& !*pos
)
2535 return __g_next(m
, pos
);
2538 static void g_stop(struct seq_file
*m
, void *p
)
2540 mutex_unlock(&graph_lock
);
2543 static int g_show(struct seq_file
*m
, void *v
)
2545 unsigned long *ptr
= v
;
2546 char str
[KSYM_SYMBOL_LEN
];
2551 if (ptr
== (unsigned long *)1) {
2552 seq_printf(m
, "#### all functions enabled ####\n");
2556 kallsyms_lookup(*ptr
, NULL
, NULL
, NULL
, str
);
2558 seq_printf(m
, "%s\n", str
);
2563 static struct seq_operations ftrace_graph_seq_ops
= {
2571 ftrace_graph_open(struct inode
*inode
, struct file
*file
)
2575 if (unlikely(ftrace_disabled
))
2578 mutex_lock(&graph_lock
);
2579 if ((file
->f_mode
& FMODE_WRITE
) &&
2580 (file
->f_flags
& O_TRUNC
)) {
2581 ftrace_graph_count
= 0;
2582 memset(ftrace_graph_funcs
, 0, sizeof(ftrace_graph_funcs
));
2585 if (file
->f_mode
& FMODE_READ
) {
2586 ret
= seq_open(file
, &ftrace_graph_seq_ops
);
2588 struct seq_file
*m
= file
->private_data
;
2589 m
->private = ftrace_graph_funcs
;
2592 file
->private_data
= ftrace_graph_funcs
;
2593 mutex_unlock(&graph_lock
);
2599 ftrace_graph_release(struct inode
*inode
, struct file
*file
)
2601 if (file
->f_mode
& FMODE_READ
)
2602 seq_release(inode
, file
);
2607 ftrace_set_func(unsigned long *array
, int *idx
, char *buffer
)
2609 struct dyn_ftrace
*rec
;
2610 struct ftrace_page
*pg
;
2618 if (ftrace_disabled
)
2622 type
= ftrace_setup_glob(buffer
, strlen(buffer
), &search
, ¬);
2626 search_len
= strlen(search
);
2628 mutex_lock(&ftrace_lock
);
2629 do_for_each_ftrace_rec(pg
, rec
) {
2631 if (*idx
>= FTRACE_GRAPH_MAX_FUNCS
)
2634 if (rec
->flags
& (FTRACE_FL_FAILED
| FTRACE_FL_FREE
))
2637 if (ftrace_match_record(rec
, search
, search_len
, type
)) {
2638 /* ensure it is not already in the array */
2640 for (i
= 0; i
< *idx
; i
++)
2641 if (array
[i
] == rec
->ip
) {
2646 array
[(*idx
)++] = rec
->ip
;
2650 } while_for_each_ftrace_rec();
2652 mutex_unlock(&ftrace_lock
);
2654 return found
? 0 : -EINVAL
;
2658 ftrace_graph_write(struct file
*file
, const char __user
*ubuf
,
2659 size_t cnt
, loff_t
*ppos
)
2661 unsigned char buffer
[FTRACE_BUFF_MAX
+1];
2662 unsigned long *array
;
2668 if (!cnt
|| cnt
< 0)
2671 mutex_lock(&graph_lock
);
2673 if (ftrace_graph_count
>= FTRACE_GRAPH_MAX_FUNCS
) {
2678 if (file
->f_mode
& FMODE_READ
) {
2679 struct seq_file
*m
= file
->private_data
;
2682 array
= file
->private_data
;
2684 ret
= get_user(ch
, ubuf
++);
2690 /* skip white space */
2691 while (cnt
&& isspace(ch
)) {
2692 ret
= get_user(ch
, ubuf
++);
2705 while (cnt
&& !isspace(ch
)) {
2706 if (index
< FTRACE_BUFF_MAX
)
2707 buffer
[index
++] = ch
;
2712 ret
= get_user(ch
, ubuf
++);
2720 /* we allow only one expression at a time */
2721 ret
= ftrace_set_func(array
, &ftrace_graph_count
, buffer
);
2725 file
->f_pos
+= read
;
2729 mutex_unlock(&graph_lock
);
2734 static const struct file_operations ftrace_graph_fops
= {
2735 .open
= ftrace_graph_open
,
2737 .write
= ftrace_graph_write
,
2738 .release
= ftrace_graph_release
,
2740 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2742 static __init
int ftrace_init_dyn_debugfs(struct dentry
*d_tracer
)
2745 trace_create_file("available_filter_functions", 0444,
2746 d_tracer
, NULL
, &ftrace_avail_fops
);
2748 trace_create_file("failures", 0444,
2749 d_tracer
, NULL
, &ftrace_failures_fops
);
2751 trace_create_file("set_ftrace_filter", 0644, d_tracer
,
2752 NULL
, &ftrace_filter_fops
);
2754 trace_create_file("set_ftrace_notrace", 0644, d_tracer
,
2755 NULL
, &ftrace_notrace_fops
);
2757 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2758 trace_create_file("set_graph_function", 0444, d_tracer
,
2760 &ftrace_graph_fops
);
2761 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2766 static int ftrace_convert_nops(struct module
*mod
,
2767 unsigned long *start
,
2772 unsigned long flags
;
2774 mutex_lock(&ftrace_lock
);
2777 addr
= ftrace_call_adjust(*p
++);
2779 * Some architecture linkers will pad between
2780 * the different mcount_loc sections of different
2781 * object files to satisfy alignments.
2782 * Skip any NULL pointers.
2786 ftrace_record_ip(addr
);
2789 /* disable interrupts to prevent kstop machine */
2790 local_irq_save(flags
);
2791 ftrace_update_code(mod
);
2792 local_irq_restore(flags
);
2793 mutex_unlock(&ftrace_lock
);
2798 #ifdef CONFIG_MODULES
2799 void ftrace_release(void *start
, void *end
)
2801 struct dyn_ftrace
*rec
;
2802 struct ftrace_page
*pg
;
2803 unsigned long s
= (unsigned long)start
;
2804 unsigned long e
= (unsigned long)end
;
2806 if (ftrace_disabled
|| !start
|| start
== end
)
2809 mutex_lock(&ftrace_lock
);
2810 do_for_each_ftrace_rec(pg
, rec
) {
2811 if ((rec
->ip
>= s
) && (rec
->ip
< e
)) {
2813 * rec->ip is changed in ftrace_free_rec()
2814 * It should not between s and e if record was freed.
2816 FTRACE_WARN_ON(rec
->flags
& FTRACE_FL_FREE
);
2817 ftrace_free_rec(rec
);
2819 } while_for_each_ftrace_rec();
2820 mutex_unlock(&ftrace_lock
);
2823 static void ftrace_init_module(struct module
*mod
,
2824 unsigned long *start
, unsigned long *end
)
2826 if (ftrace_disabled
|| start
== end
)
2828 ftrace_convert_nops(mod
, start
, end
);
2831 static int ftrace_module_notify(struct notifier_block
*self
,
2832 unsigned long val
, void *data
)
2834 struct module
*mod
= data
;
2837 case MODULE_STATE_COMING
:
2838 ftrace_init_module(mod
, mod
->ftrace_callsites
,
2839 mod
->ftrace_callsites
+
2840 mod
->num_ftrace_callsites
);
2842 case MODULE_STATE_GOING
:
2843 ftrace_release(mod
->ftrace_callsites
,
2844 mod
->ftrace_callsites
+
2845 mod
->num_ftrace_callsites
);
2852 static int ftrace_module_notify(struct notifier_block
*self
,
2853 unsigned long val
, void *data
)
2857 #endif /* CONFIG_MODULES */
2859 struct notifier_block ftrace_module_nb
= {
2860 .notifier_call
= ftrace_module_notify
,
2864 extern unsigned long __start_mcount_loc
[];
2865 extern unsigned long __stop_mcount_loc
[];
2867 void __init
ftrace_init(void)
2869 unsigned long count
, addr
, flags
;
2872 /* Keep the ftrace pointer to the stub */
2873 addr
= (unsigned long)ftrace_stub
;
2875 local_irq_save(flags
);
2876 ftrace_dyn_arch_init(&addr
);
2877 local_irq_restore(flags
);
2879 /* ftrace_dyn_arch_init places the return code in addr */
2883 count
= __stop_mcount_loc
- __start_mcount_loc
;
2885 ret
= ftrace_dyn_table_alloc(count
);
2889 last_ftrace_enabled
= ftrace_enabled
= 1;
2891 ret
= ftrace_convert_nops(NULL
,
2895 ret
= register_module_notifier(&ftrace_module_nb
);
2897 pr_warning("Failed to register trace ftrace module notifier\n");
2899 set_ftrace_early_filters();
2903 ftrace_disabled
= 1;
2908 static int __init
ftrace_nodyn_init(void)
2913 device_initcall(ftrace_nodyn_init
);
2915 static inline int ftrace_init_dyn_debugfs(struct dentry
*d_tracer
) { return 0; }
2916 static inline void ftrace_startup_enable(int command
) { }
2917 /* Keep as macros so we do not need to define the commands */
2918 # define ftrace_startup(command) do { } while (0)
2919 # define ftrace_shutdown(command) do { } while (0)
2920 # define ftrace_startup_sysctl() do { } while (0)
2921 # define ftrace_shutdown_sysctl() do { } while (0)
2922 #endif /* CONFIG_DYNAMIC_FTRACE */
2925 ftrace_pid_read(struct file
*file
, char __user
*ubuf
,
2926 size_t cnt
, loff_t
*ppos
)
2931 if (ftrace_pid_trace
== ftrace_swapper_pid
)
2932 r
= sprintf(buf
, "swapper tasks\n");
2933 else if (ftrace_pid_trace
)
2934 r
= sprintf(buf
, "%u\n", pid_vnr(ftrace_pid_trace
));
2936 r
= sprintf(buf
, "no pid\n");
2938 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2941 static void clear_ftrace_swapper(void)
2943 struct task_struct
*p
;
2947 for_each_online_cpu(cpu
) {
2949 clear_tsk_trace_trace(p
);
2954 static void set_ftrace_swapper(void)
2956 struct task_struct
*p
;
2960 for_each_online_cpu(cpu
) {
2962 set_tsk_trace_trace(p
);
2967 static void clear_ftrace_pid(struct pid
*pid
)
2969 struct task_struct
*p
;
2972 do_each_pid_task(pid
, PIDTYPE_PID
, p
) {
2973 clear_tsk_trace_trace(p
);
2974 } while_each_pid_task(pid
, PIDTYPE_PID
, p
);
2980 static void set_ftrace_pid(struct pid
*pid
)
2982 struct task_struct
*p
;
2985 do_each_pid_task(pid
, PIDTYPE_PID
, p
) {
2986 set_tsk_trace_trace(p
);
2987 } while_each_pid_task(pid
, PIDTYPE_PID
, p
);
2991 static void clear_ftrace_pid_task(struct pid
**pid
)
2993 if (*pid
== ftrace_swapper_pid
)
2994 clear_ftrace_swapper();
2996 clear_ftrace_pid(*pid
);
3001 static void set_ftrace_pid_task(struct pid
*pid
)
3003 if (pid
== ftrace_swapper_pid
)
3004 set_ftrace_swapper();
3006 set_ftrace_pid(pid
);
3010 ftrace_pid_write(struct file
*filp
, const char __user
*ubuf
,
3011 size_t cnt
, loff_t
*ppos
)
3018 if (cnt
>= sizeof(buf
))
3021 if (copy_from_user(&buf
, ubuf
, cnt
))
3026 ret
= strict_strtol(buf
, 10, &val
);
3030 mutex_lock(&ftrace_lock
);
3032 /* disable pid tracing */
3033 if (!ftrace_pid_trace
)
3036 clear_ftrace_pid_task(&ftrace_pid_trace
);
3039 /* swapper task is special */
3041 pid
= ftrace_swapper_pid
;
3042 if (pid
== ftrace_pid_trace
)
3045 pid
= find_get_pid(val
);
3047 if (pid
== ftrace_pid_trace
) {
3053 if (ftrace_pid_trace
)
3054 clear_ftrace_pid_task(&ftrace_pid_trace
);
3059 ftrace_pid_trace
= pid
;
3061 set_ftrace_pid_task(ftrace_pid_trace
);
3064 /* update the function call */
3065 ftrace_update_pid_func();
3066 ftrace_startup_enable(0);
3069 mutex_unlock(&ftrace_lock
);
3074 static const struct file_operations ftrace_pid_fops
= {
3075 .read
= ftrace_pid_read
,
3076 .write
= ftrace_pid_write
,
3079 static __init
int ftrace_init_debugfs(void)
3081 struct dentry
*d_tracer
;
3083 d_tracer
= tracing_init_dentry();
3087 ftrace_init_dyn_debugfs(d_tracer
);
3089 trace_create_file("set_ftrace_pid", 0644, d_tracer
,
3090 NULL
, &ftrace_pid_fops
);
3092 ftrace_profile_debugfs(d_tracer
);
3096 fs_initcall(ftrace_init_debugfs
);
3099 * ftrace_kill - kill ftrace
3101 * This function should be used by panic code. It stops ftrace
3102 * but in a not so nice way. If you need to simply kill ftrace
3103 * from a non-atomic section, use ftrace_kill.
3105 void ftrace_kill(void)
3107 ftrace_disabled
= 1;
3109 clear_ftrace_function();
3113 * register_ftrace_function - register a function for profiling
3114 * @ops - ops structure that holds the function for profiling.
3116 * Register a function to be called by all functions in the
3119 * Note: @ops->func and all the functions it calls must be labeled
3120 * with "notrace", otherwise it will go into a
3123 int register_ftrace_function(struct ftrace_ops
*ops
)
3127 if (unlikely(ftrace_disabled
))
3130 mutex_lock(&ftrace_lock
);
3132 ret
= __register_ftrace_function(ops
);
3135 mutex_unlock(&ftrace_lock
);
3140 * unregister_ftrace_function - unregister a function for profiling.
3141 * @ops - ops structure that holds the function to unregister
3143 * Unregister a function that was added to be called by ftrace profiling.
3145 int unregister_ftrace_function(struct ftrace_ops
*ops
)
3149 mutex_lock(&ftrace_lock
);
3150 ret
= __unregister_ftrace_function(ops
);
3152 mutex_unlock(&ftrace_lock
);
3158 ftrace_enable_sysctl(struct ctl_table
*table
, int write
,
3159 struct file
*file
, void __user
*buffer
, size_t *lenp
,
3164 if (unlikely(ftrace_disabled
))
3167 mutex_lock(&ftrace_lock
);
3169 ret
= proc_dointvec(table
, write
, file
, buffer
, lenp
, ppos
);
3171 if (ret
|| !write
|| (last_ftrace_enabled
== !!ftrace_enabled
))
3174 last_ftrace_enabled
= !!ftrace_enabled
;
3176 if (ftrace_enabled
) {
3178 ftrace_startup_sysctl();
3180 /* we are starting ftrace again */
3181 if (ftrace_list
!= &ftrace_list_end
) {
3182 if (ftrace_list
->next
== &ftrace_list_end
)
3183 ftrace_trace_function
= ftrace_list
->func
;
3185 ftrace_trace_function
= ftrace_list_func
;
3189 /* stopping ftrace calls (just send to ftrace_stub) */
3190 ftrace_trace_function
= ftrace_stub
;
3192 ftrace_shutdown_sysctl();
3196 mutex_unlock(&ftrace_lock
);
3200 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3202 static int ftrace_graph_active
;
3203 static struct notifier_block ftrace_suspend_notifier
;
3205 int ftrace_graph_entry_stub(struct ftrace_graph_ent
*trace
)
3210 /* The callbacks that hook a function */
3211 trace_func_graph_ret_t ftrace_graph_return
=
3212 (trace_func_graph_ret_t
)ftrace_stub
;
3213 trace_func_graph_ent_t ftrace_graph_entry
= ftrace_graph_entry_stub
;
3215 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
3216 static int alloc_retstack_tasklist(struct ftrace_ret_stack
**ret_stack_list
)
3220 unsigned long flags
;
3221 int start
= 0, end
= FTRACE_RETSTACK_ALLOC_SIZE
;
3222 struct task_struct
*g
, *t
;
3224 for (i
= 0; i
< FTRACE_RETSTACK_ALLOC_SIZE
; i
++) {
3225 ret_stack_list
[i
] = kmalloc(FTRACE_RETFUNC_DEPTH
3226 * sizeof(struct ftrace_ret_stack
),
3228 if (!ret_stack_list
[i
]) {
3236 read_lock_irqsave(&tasklist_lock
, flags
);
3237 do_each_thread(g
, t
) {
3243 if (t
->ret_stack
== NULL
) {
3244 atomic_set(&t
->tracing_graph_pause
, 0);
3245 atomic_set(&t
->trace_overrun
, 0);
3246 t
->curr_ret_stack
= -1;
3247 /* Make sure the tasks see the -1 first: */
3249 t
->ret_stack
= ret_stack_list
[start
++];
3251 } while_each_thread(g
, t
);
3254 read_unlock_irqrestore(&tasklist_lock
, flags
);
3256 for (i
= start
; i
< end
; i
++)
3257 kfree(ret_stack_list
[i
]);
3262 ftrace_graph_probe_sched_switch(struct rq
*__rq
, struct task_struct
*prev
,
3263 struct task_struct
*next
)
3265 unsigned long long timestamp
;
3269 * Does the user want to count the time a function was asleep.
3270 * If so, do not update the time stamps.
3272 if (trace_flags
& TRACE_ITER_SLEEP_TIME
)
3275 timestamp
= trace_clock_local();
3277 prev
->ftrace_timestamp
= timestamp
;
3279 /* only process tasks that we timestamped */
3280 if (!next
->ftrace_timestamp
)
3284 * Update all the counters in next to make up for the
3285 * time next was sleeping.
3287 timestamp
-= next
->ftrace_timestamp
;
3289 for (index
= next
->curr_ret_stack
; index
>= 0; index
--)
3290 next
->ret_stack
[index
].calltime
+= timestamp
;
3293 /* Allocate a return stack for each task */
3294 static int start_graph_tracing(void)
3296 struct ftrace_ret_stack
**ret_stack_list
;
3299 ret_stack_list
= kmalloc(FTRACE_RETSTACK_ALLOC_SIZE
*
3300 sizeof(struct ftrace_ret_stack
*),
3303 if (!ret_stack_list
)
3306 /* The cpu_boot init_task->ret_stack will never be freed */
3307 for_each_online_cpu(cpu
) {
3308 if (!idle_task(cpu
)->ret_stack
)
3309 ftrace_graph_init_task(idle_task(cpu
));
3313 ret
= alloc_retstack_tasklist(ret_stack_list
);
3314 } while (ret
== -EAGAIN
);
3317 ret
= register_trace_sched_switch(ftrace_graph_probe_sched_switch
);
3319 pr_info("ftrace_graph: Couldn't activate tracepoint"
3320 " probe to kernel_sched_switch\n");
3323 kfree(ret_stack_list
);
3328 * Hibernation protection.
3329 * The state of the current task is too much unstable during
3330 * suspend/restore to disk. We want to protect against that.
3333 ftrace_suspend_notifier_call(struct notifier_block
*bl
, unsigned long state
,
3337 case PM_HIBERNATION_PREPARE
:
3338 pause_graph_tracing();
3341 case PM_POST_HIBERNATION
:
3342 unpause_graph_tracing();
3348 int register_ftrace_graph(trace_func_graph_ret_t retfunc
,
3349 trace_func_graph_ent_t entryfunc
)
3353 mutex_lock(&ftrace_lock
);
3355 /* we currently allow only one tracer registered at a time */
3356 if (ftrace_graph_active
) {
3361 ftrace_suspend_notifier
.notifier_call
= ftrace_suspend_notifier_call
;
3362 register_pm_notifier(&ftrace_suspend_notifier
);
3364 ftrace_graph_active
++;
3365 ret
= start_graph_tracing();
3367 ftrace_graph_active
--;
3371 ftrace_graph_return
= retfunc
;
3372 ftrace_graph_entry
= entryfunc
;
3374 ftrace_startup(FTRACE_START_FUNC_RET
);
3377 mutex_unlock(&ftrace_lock
);
3381 void unregister_ftrace_graph(void)
3383 mutex_lock(&ftrace_lock
);
3385 if (unlikely(!ftrace_graph_active
))
3388 ftrace_graph_active
--;
3389 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch
);
3390 ftrace_graph_return
= (trace_func_graph_ret_t
)ftrace_stub
;
3391 ftrace_graph_entry
= ftrace_graph_entry_stub
;
3392 ftrace_shutdown(FTRACE_STOP_FUNC_RET
);
3393 unregister_pm_notifier(&ftrace_suspend_notifier
);
3396 mutex_unlock(&ftrace_lock
);
3399 /* Allocate a return stack for newly created task */
3400 void ftrace_graph_init_task(struct task_struct
*t
)
3402 /* Make sure we do not use the parent ret_stack */
3403 t
->ret_stack
= NULL
;
3405 if (ftrace_graph_active
) {
3406 struct ftrace_ret_stack
*ret_stack
;
3408 ret_stack
= kmalloc(FTRACE_RETFUNC_DEPTH
3409 * sizeof(struct ftrace_ret_stack
),
3413 t
->curr_ret_stack
= -1;
3414 atomic_set(&t
->tracing_graph_pause
, 0);
3415 atomic_set(&t
->trace_overrun
, 0);
3416 t
->ftrace_timestamp
= 0;
3417 /* make curr_ret_stack visable before we add the ret_stack */
3419 t
->ret_stack
= ret_stack
;
3423 void ftrace_graph_exit_task(struct task_struct
*t
)
3425 struct ftrace_ret_stack
*ret_stack
= t
->ret_stack
;
3427 t
->ret_stack
= NULL
;
3428 /* NULL must become visible to IRQs before we free it: */
3434 void ftrace_graph_stop(void)