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 Nadia Yvette Chambers
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/bsearch.h>
26 #include <linux/module.h>
27 #include <linux/ftrace.h>
28 #include <linux/sysctl.h>
29 #include <linux/slab.h>
30 #include <linux/ctype.h>
31 #include <linux/sort.h>
32 #include <linux/list.h>
33 #include <linux/hash.h>
34 #include <linux/rcupdate.h>
36 #include <trace/events/sched.h>
38 #include <asm/setup.h>
40 #include "trace_output.h"
41 #include "trace_stat.h"
43 #define FTRACE_WARN_ON(cond) \
51 #define FTRACE_WARN_ON_ONCE(cond) \
54 if (WARN_ON_ONCE(___r)) \
59 /* hash bits for specific function selection */
60 #define FTRACE_HASH_BITS 7
61 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
62 #define FTRACE_HASH_DEFAULT_BITS 10
63 #define FTRACE_HASH_MAX_BITS 12
65 #define FL_GLOBAL_CONTROL_MASK (FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_CONTROL)
67 static struct ftrace_ops ftrace_list_end __read_mostly
= {
69 .flags
= FTRACE_OPS_FL_RECURSION_SAFE
| FTRACE_OPS_FL_STUB
,
72 /* ftrace_enabled is a method to turn ftrace on or off */
73 int ftrace_enabled __read_mostly
;
74 static int last_ftrace_enabled
;
76 /* Quick disabling of function tracer. */
77 int function_trace_stop __read_mostly
;
79 /* Current function tracing op */
80 struct ftrace_ops
*function_trace_op __read_mostly
= &ftrace_list_end
;
82 /* List for set_ftrace_pid's pids. */
83 LIST_HEAD(ftrace_pids
);
85 struct list_head list
;
90 * ftrace_disabled is set when an anomaly is discovered.
91 * ftrace_disabled is much stronger than ftrace_enabled.
93 static int ftrace_disabled __read_mostly
;
95 static DEFINE_MUTEX(ftrace_lock
);
97 static struct ftrace_ops
*ftrace_global_list __read_mostly
= &ftrace_list_end
;
98 static struct ftrace_ops
*ftrace_control_list __read_mostly
= &ftrace_list_end
;
99 static struct ftrace_ops
*ftrace_ops_list __read_mostly
= &ftrace_list_end
;
100 ftrace_func_t ftrace_trace_function __read_mostly
= ftrace_stub
;
101 ftrace_func_t ftrace_pid_function __read_mostly
= ftrace_stub
;
102 static struct ftrace_ops global_ops
;
103 static struct ftrace_ops control_ops
;
105 #if ARCH_SUPPORTS_FTRACE_OPS
106 static void ftrace_ops_list_func(unsigned long ip
, unsigned long parent_ip
,
107 struct ftrace_ops
*op
, struct pt_regs
*regs
);
109 /* See comment below, where ftrace_ops_list_func is defined */
110 static void ftrace_ops_no_ops(unsigned long ip
, unsigned long parent_ip
);
111 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
115 * Traverse the ftrace_global_list, invoking all entries. The reason that we
116 * can use rcu_dereference_raw() is that elements removed from this list
117 * are simply leaked, so there is no need to interact with a grace-period
118 * mechanism. The rcu_dereference_raw() calls are needed to handle
119 * concurrent insertions into the ftrace_global_list.
121 * Silly Alpha and silly pointer-speculation compiler optimizations!
123 #define do_for_each_ftrace_op(op, list) \
124 op = rcu_dereference_raw(list); \
128 * Optimized for just a single item in the list (as that is the normal case).
130 #define while_for_each_ftrace_op(op) \
131 while (likely(op = rcu_dereference_raw((op)->next)) && \
132 unlikely((op) != &ftrace_list_end))
135 * ftrace_nr_registered_ops - return number of ops registered
137 * Returns the number of ftrace_ops registered and tracing functions
139 int ftrace_nr_registered_ops(void)
141 struct ftrace_ops
*ops
;
144 mutex_lock(&ftrace_lock
);
146 for (ops
= ftrace_ops_list
;
147 ops
!= &ftrace_list_end
; ops
= ops
->next
)
150 mutex_unlock(&ftrace_lock
);
156 ftrace_global_list_func(unsigned long ip
, unsigned long parent_ip
,
157 struct ftrace_ops
*op
, struct pt_regs
*regs
)
161 bit
= trace_test_and_set_recursion(TRACE_GLOBAL_START
, TRACE_GLOBAL_MAX
);
165 do_for_each_ftrace_op(op
, ftrace_global_list
) {
166 op
->func(ip
, parent_ip
, op
, regs
);
167 } while_for_each_ftrace_op(op
);
169 trace_clear_recursion(bit
);
172 static void ftrace_pid_func(unsigned long ip
, unsigned long parent_ip
,
173 struct ftrace_ops
*op
, struct pt_regs
*regs
)
175 if (!test_tsk_trace_trace(current
))
178 ftrace_pid_function(ip
, parent_ip
, op
, regs
);
181 static void set_ftrace_pid_function(ftrace_func_t func
)
183 /* do not set ftrace_pid_function to itself! */
184 if (func
!= ftrace_pid_func
)
185 ftrace_pid_function
= func
;
189 * clear_ftrace_function - reset the ftrace function
191 * This NULLs the ftrace function and in essence stops
192 * tracing. There may be lag
194 void clear_ftrace_function(void)
196 ftrace_trace_function
= ftrace_stub
;
197 ftrace_pid_function
= ftrace_stub
;
200 static void control_ops_disable_all(struct ftrace_ops
*ops
)
204 for_each_possible_cpu(cpu
)
205 *per_cpu_ptr(ops
->disabled
, cpu
) = 1;
208 static int control_ops_alloc(struct ftrace_ops
*ops
)
210 int __percpu
*disabled
;
212 disabled
= alloc_percpu(int);
216 ops
->disabled
= disabled
;
217 control_ops_disable_all(ops
);
221 static void control_ops_free(struct ftrace_ops
*ops
)
223 free_percpu(ops
->disabled
);
226 static void update_global_ops(void)
231 * If there's only one function registered, then call that
232 * function directly. Otherwise, we need to iterate over the
233 * registered callers.
235 if (ftrace_global_list
== &ftrace_list_end
||
236 ftrace_global_list
->next
== &ftrace_list_end
) {
237 func
= ftrace_global_list
->func
;
239 * As we are calling the function directly.
240 * If it does not have recursion protection,
241 * the function_trace_op needs to be updated
244 if (ftrace_global_list
->flags
& FTRACE_OPS_FL_RECURSION_SAFE
)
245 global_ops
.flags
|= FTRACE_OPS_FL_RECURSION_SAFE
;
247 global_ops
.flags
&= ~FTRACE_OPS_FL_RECURSION_SAFE
;
249 func
= ftrace_global_list_func
;
250 /* The list has its own recursion protection. */
251 global_ops
.flags
|= FTRACE_OPS_FL_RECURSION_SAFE
;
255 /* If we filter on pids, update to use the pid function */
256 if (!list_empty(&ftrace_pids
)) {
257 set_ftrace_pid_function(func
);
258 func
= ftrace_pid_func
;
261 global_ops
.func
= func
;
264 static void update_ftrace_function(void)
271 * If we are at the end of the list and this ops is
272 * recursion safe and not dynamic and the arch supports passing ops,
273 * then have the mcount trampoline call the function directly.
275 if (ftrace_ops_list
== &ftrace_list_end
||
276 (ftrace_ops_list
->next
== &ftrace_list_end
&&
277 !(ftrace_ops_list
->flags
& FTRACE_OPS_FL_DYNAMIC
) &&
278 (ftrace_ops_list
->flags
& FTRACE_OPS_FL_RECURSION_SAFE
) &&
279 !FTRACE_FORCE_LIST_FUNC
)) {
280 /* Set the ftrace_ops that the arch callback uses */
281 if (ftrace_ops_list
== &global_ops
)
282 function_trace_op
= ftrace_global_list
;
284 function_trace_op
= ftrace_ops_list
;
285 func
= ftrace_ops_list
->func
;
287 /* Just use the default ftrace_ops */
288 function_trace_op
= &ftrace_list_end
;
289 func
= ftrace_ops_list_func
;
292 ftrace_trace_function
= func
;
295 static void add_ftrace_ops(struct ftrace_ops
**list
, struct ftrace_ops
*ops
)
299 * We are entering ops into the list but another
300 * CPU might be walking that list. We need to make sure
301 * the ops->next pointer is valid before another CPU sees
302 * the ops pointer included into the list.
304 rcu_assign_pointer(*list
, ops
);
307 static int remove_ftrace_ops(struct ftrace_ops
**list
, struct ftrace_ops
*ops
)
309 struct ftrace_ops
**p
;
312 * If we are removing the last function, then simply point
313 * to the ftrace_stub.
315 if (*list
== ops
&& ops
->next
== &ftrace_list_end
) {
316 *list
= &ftrace_list_end
;
320 for (p
= list
; *p
!= &ftrace_list_end
; p
= &(*p
)->next
)
331 static void add_ftrace_list_ops(struct ftrace_ops
**list
,
332 struct ftrace_ops
*main_ops
,
333 struct ftrace_ops
*ops
)
335 int first
= *list
== &ftrace_list_end
;
336 add_ftrace_ops(list
, ops
);
338 add_ftrace_ops(&ftrace_ops_list
, main_ops
);
341 static int remove_ftrace_list_ops(struct ftrace_ops
**list
,
342 struct ftrace_ops
*main_ops
,
343 struct ftrace_ops
*ops
)
345 int ret
= remove_ftrace_ops(list
, ops
);
346 if (!ret
&& *list
== &ftrace_list_end
)
347 ret
= remove_ftrace_ops(&ftrace_ops_list
, main_ops
);
351 static int __register_ftrace_function(struct ftrace_ops
*ops
)
353 if (unlikely(ftrace_disabled
))
356 if (FTRACE_WARN_ON(ops
== &global_ops
))
359 if (WARN_ON(ops
->flags
& FTRACE_OPS_FL_ENABLED
))
362 /* We don't support both control and global flags set. */
363 if ((ops
->flags
& FL_GLOBAL_CONTROL_MASK
) == FL_GLOBAL_CONTROL_MASK
)
366 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
368 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
369 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
370 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
372 if (ops
->flags
& FTRACE_OPS_FL_SAVE_REGS
&&
373 !(ops
->flags
& FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED
))
376 if (ops
->flags
& FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED
)
377 ops
->flags
|= FTRACE_OPS_FL_SAVE_REGS
;
380 if (!core_kernel_data((unsigned long)ops
))
381 ops
->flags
|= FTRACE_OPS_FL_DYNAMIC
;
383 if (ops
->flags
& FTRACE_OPS_FL_GLOBAL
) {
384 add_ftrace_list_ops(&ftrace_global_list
, &global_ops
, ops
);
385 ops
->flags
|= FTRACE_OPS_FL_ENABLED
;
386 } else if (ops
->flags
& FTRACE_OPS_FL_CONTROL
) {
387 if (control_ops_alloc(ops
))
389 add_ftrace_list_ops(&ftrace_control_list
, &control_ops
, ops
);
391 add_ftrace_ops(&ftrace_ops_list
, ops
);
394 update_ftrace_function();
399 static int __unregister_ftrace_function(struct ftrace_ops
*ops
)
406 if (WARN_ON(!(ops
->flags
& FTRACE_OPS_FL_ENABLED
)))
409 if (FTRACE_WARN_ON(ops
== &global_ops
))
412 if (ops
->flags
& FTRACE_OPS_FL_GLOBAL
) {
413 ret
= remove_ftrace_list_ops(&ftrace_global_list
,
416 ops
->flags
&= ~FTRACE_OPS_FL_ENABLED
;
417 } else if (ops
->flags
& FTRACE_OPS_FL_CONTROL
) {
418 ret
= remove_ftrace_list_ops(&ftrace_control_list
,
422 * The ftrace_ops is now removed from the list,
423 * so there'll be no new users. We must ensure
424 * all current users are done before we free
428 control_ops_free(ops
);
431 ret
= remove_ftrace_ops(&ftrace_ops_list
, ops
);
437 update_ftrace_function();
440 * Dynamic ops may be freed, we must make sure that all
441 * callers are done before leaving this function.
443 if (ops
->flags
& FTRACE_OPS_FL_DYNAMIC
)
449 static void ftrace_update_pid_func(void)
451 /* Only do something if we are tracing something */
452 if (ftrace_trace_function
== ftrace_stub
)
455 update_ftrace_function();
458 #ifdef CONFIG_FUNCTION_PROFILER
459 struct ftrace_profile
{
460 struct hlist_node node
;
462 unsigned long counter
;
463 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
464 unsigned long long time
;
465 unsigned long long time_squared
;
469 struct ftrace_profile_page
{
470 struct ftrace_profile_page
*next
;
472 struct ftrace_profile records
[];
475 struct ftrace_profile_stat
{
477 struct hlist_head
*hash
;
478 struct ftrace_profile_page
*pages
;
479 struct ftrace_profile_page
*start
;
480 struct tracer_stat stat
;
483 #define PROFILE_RECORDS_SIZE \
484 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
486 #define PROFILES_PER_PAGE \
487 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
489 static int ftrace_profile_enabled __read_mostly
;
491 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
492 static DEFINE_MUTEX(ftrace_profile_lock
);
494 static DEFINE_PER_CPU(struct ftrace_profile_stat
, ftrace_profile_stats
);
496 #define FTRACE_PROFILE_HASH_BITS 10
497 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
500 function_stat_next(void *v
, int idx
)
502 struct ftrace_profile
*rec
= v
;
503 struct ftrace_profile_page
*pg
;
505 pg
= (struct ftrace_profile_page
*)((unsigned long)rec
& PAGE_MASK
);
511 if ((void *)rec
>= (void *)&pg
->records
[pg
->index
]) {
515 rec
= &pg
->records
[0];
523 static void *function_stat_start(struct tracer_stat
*trace
)
525 struct ftrace_profile_stat
*stat
=
526 container_of(trace
, struct ftrace_profile_stat
, stat
);
528 if (!stat
|| !stat
->start
)
531 return function_stat_next(&stat
->start
->records
[0], 0);
534 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
535 /* function graph compares on total time */
536 static int function_stat_cmp(void *p1
, void *p2
)
538 struct ftrace_profile
*a
= p1
;
539 struct ftrace_profile
*b
= p2
;
541 if (a
->time
< b
->time
)
543 if (a
->time
> b
->time
)
549 /* not function graph compares against hits */
550 static int function_stat_cmp(void *p1
, void *p2
)
552 struct ftrace_profile
*a
= p1
;
553 struct ftrace_profile
*b
= p2
;
555 if (a
->counter
< b
->counter
)
557 if (a
->counter
> b
->counter
)
564 static int function_stat_headers(struct seq_file
*m
)
566 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
567 seq_printf(m
, " Function "
570 "--- ---- --- ---\n");
572 seq_printf(m
, " Function Hit\n"
578 static int function_stat_show(struct seq_file
*m
, void *v
)
580 struct ftrace_profile
*rec
= v
;
581 char str
[KSYM_SYMBOL_LEN
];
583 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
584 static struct trace_seq s
;
585 unsigned long long avg
;
586 unsigned long long stddev
;
588 mutex_lock(&ftrace_profile_lock
);
590 /* we raced with function_profile_reset() */
591 if (unlikely(rec
->counter
== 0)) {
596 kallsyms_lookup(rec
->ip
, NULL
, NULL
, NULL
, str
);
597 seq_printf(m
, " %-30.30s %10lu", str
, rec
->counter
);
599 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
602 do_div(avg
, rec
->counter
);
604 /* Sample standard deviation (s^2) */
605 if (rec
->counter
<= 1)
608 stddev
= rec
->time_squared
- rec
->counter
* avg
* avg
;
610 * Divide only 1000 for ns^2 -> us^2 conversion.
611 * trace_print_graph_duration will divide 1000 again.
613 do_div(stddev
, (rec
->counter
- 1) * 1000);
617 trace_print_graph_duration(rec
->time
, &s
);
618 trace_seq_puts(&s
, " ");
619 trace_print_graph_duration(avg
, &s
);
620 trace_seq_puts(&s
, " ");
621 trace_print_graph_duration(stddev
, &s
);
622 trace_print_seq(m
, &s
);
626 mutex_unlock(&ftrace_profile_lock
);
631 static void ftrace_profile_reset(struct ftrace_profile_stat
*stat
)
633 struct ftrace_profile_page
*pg
;
635 pg
= stat
->pages
= stat
->start
;
638 memset(pg
->records
, 0, PROFILE_RECORDS_SIZE
);
643 memset(stat
->hash
, 0,
644 FTRACE_PROFILE_HASH_SIZE
* sizeof(struct hlist_head
));
647 int ftrace_profile_pages_init(struct ftrace_profile_stat
*stat
)
649 struct ftrace_profile_page
*pg
;
654 /* If we already allocated, do nothing */
658 stat
->pages
= (void *)get_zeroed_page(GFP_KERNEL
);
662 #ifdef CONFIG_DYNAMIC_FTRACE
663 functions
= ftrace_update_tot_cnt
;
666 * We do not know the number of functions that exist because
667 * dynamic tracing is what counts them. With past experience
668 * we have around 20K functions. That should be more than enough.
669 * It is highly unlikely we will execute every function in
675 pg
= stat
->start
= stat
->pages
;
677 pages
= DIV_ROUND_UP(functions
, PROFILES_PER_PAGE
);
679 for (i
= 1; i
< pages
; i
++) {
680 pg
->next
= (void *)get_zeroed_page(GFP_KERNEL
);
691 unsigned long tmp
= (unsigned long)pg
;
703 static int ftrace_profile_init_cpu(int cpu
)
705 struct ftrace_profile_stat
*stat
;
708 stat
= &per_cpu(ftrace_profile_stats
, cpu
);
711 /* If the profile is already created, simply reset it */
712 ftrace_profile_reset(stat
);
717 * We are profiling all functions, but usually only a few thousand
718 * functions are hit. We'll make a hash of 1024 items.
720 size
= FTRACE_PROFILE_HASH_SIZE
;
722 stat
->hash
= kzalloc(sizeof(struct hlist_head
) * size
, GFP_KERNEL
);
727 /* Preallocate the function profiling pages */
728 if (ftrace_profile_pages_init(stat
) < 0) {
737 static int ftrace_profile_init(void)
742 for_each_online_cpu(cpu
) {
743 ret
= ftrace_profile_init_cpu(cpu
);
751 /* interrupts must be disabled */
752 static struct ftrace_profile
*
753 ftrace_find_profiled_func(struct ftrace_profile_stat
*stat
, unsigned long ip
)
755 struct ftrace_profile
*rec
;
756 struct hlist_head
*hhd
;
759 key
= hash_long(ip
, FTRACE_PROFILE_HASH_BITS
);
760 hhd
= &stat
->hash
[key
];
762 if (hlist_empty(hhd
))
765 hlist_for_each_entry_rcu(rec
, hhd
, node
) {
773 static void ftrace_add_profile(struct ftrace_profile_stat
*stat
,
774 struct ftrace_profile
*rec
)
778 key
= hash_long(rec
->ip
, FTRACE_PROFILE_HASH_BITS
);
779 hlist_add_head_rcu(&rec
->node
, &stat
->hash
[key
]);
783 * The memory is already allocated, this simply finds a new record to use.
785 static struct ftrace_profile
*
786 ftrace_profile_alloc(struct ftrace_profile_stat
*stat
, unsigned long ip
)
788 struct ftrace_profile
*rec
= NULL
;
790 /* prevent recursion (from NMIs) */
791 if (atomic_inc_return(&stat
->disabled
) != 1)
795 * Try to find the function again since an NMI
796 * could have added it
798 rec
= ftrace_find_profiled_func(stat
, ip
);
802 if (stat
->pages
->index
== PROFILES_PER_PAGE
) {
803 if (!stat
->pages
->next
)
805 stat
->pages
= stat
->pages
->next
;
808 rec
= &stat
->pages
->records
[stat
->pages
->index
++];
810 ftrace_add_profile(stat
, rec
);
813 atomic_dec(&stat
->disabled
);
819 function_profile_call(unsigned long ip
, unsigned long parent_ip
,
820 struct ftrace_ops
*ops
, struct pt_regs
*regs
)
822 struct ftrace_profile_stat
*stat
;
823 struct ftrace_profile
*rec
;
826 if (!ftrace_profile_enabled
)
829 local_irq_save(flags
);
831 stat
= &__get_cpu_var(ftrace_profile_stats
);
832 if (!stat
->hash
|| !ftrace_profile_enabled
)
835 rec
= ftrace_find_profiled_func(stat
, ip
);
837 rec
= ftrace_profile_alloc(stat
, ip
);
844 local_irq_restore(flags
);
847 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
848 static int profile_graph_entry(struct ftrace_graph_ent
*trace
)
850 function_profile_call(trace
->func
, 0, NULL
, NULL
);
854 static void profile_graph_return(struct ftrace_graph_ret
*trace
)
856 struct ftrace_profile_stat
*stat
;
857 unsigned long long calltime
;
858 struct ftrace_profile
*rec
;
861 local_irq_save(flags
);
862 stat
= &__get_cpu_var(ftrace_profile_stats
);
863 if (!stat
->hash
|| !ftrace_profile_enabled
)
866 /* If the calltime was zero'd ignore it */
867 if (!trace
->calltime
)
870 calltime
= trace
->rettime
- trace
->calltime
;
872 if (!(trace_flags
& TRACE_ITER_GRAPH_TIME
)) {
875 index
= trace
->depth
;
877 /* Append this call time to the parent time to subtract */
879 current
->ret_stack
[index
- 1].subtime
+= calltime
;
881 if (current
->ret_stack
[index
].subtime
< calltime
)
882 calltime
-= current
->ret_stack
[index
].subtime
;
887 rec
= ftrace_find_profiled_func(stat
, trace
->func
);
889 rec
->time
+= calltime
;
890 rec
->time_squared
+= calltime
* calltime
;
894 local_irq_restore(flags
);
897 static int register_ftrace_profiler(void)
899 return register_ftrace_graph(&profile_graph_return
,
900 &profile_graph_entry
);
903 static void unregister_ftrace_profiler(void)
905 unregister_ftrace_graph();
908 static struct ftrace_ops ftrace_profile_ops __read_mostly
= {
909 .func
= function_profile_call
,
910 .flags
= FTRACE_OPS_FL_RECURSION_SAFE
,
913 static int register_ftrace_profiler(void)
915 return register_ftrace_function(&ftrace_profile_ops
);
918 static void unregister_ftrace_profiler(void)
920 unregister_ftrace_function(&ftrace_profile_ops
);
922 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
925 ftrace_profile_write(struct file
*filp
, const char __user
*ubuf
,
926 size_t cnt
, loff_t
*ppos
)
931 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
937 mutex_lock(&ftrace_profile_lock
);
938 if (ftrace_profile_enabled
^ val
) {
940 ret
= ftrace_profile_init();
946 ret
= register_ftrace_profiler();
951 ftrace_profile_enabled
= 1;
953 ftrace_profile_enabled
= 0;
955 * unregister_ftrace_profiler calls stop_machine
956 * so this acts like an synchronize_sched.
958 unregister_ftrace_profiler();
962 mutex_unlock(&ftrace_profile_lock
);
970 ftrace_profile_read(struct file
*filp
, char __user
*ubuf
,
971 size_t cnt
, loff_t
*ppos
)
973 char buf
[64]; /* big enough to hold a number */
976 r
= sprintf(buf
, "%u\n", ftrace_profile_enabled
);
977 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
980 static const struct file_operations ftrace_profile_fops
= {
981 .open
= tracing_open_generic
,
982 .read
= ftrace_profile_read
,
983 .write
= ftrace_profile_write
,
984 .llseek
= default_llseek
,
987 /* used to initialize the real stat files */
988 static struct tracer_stat function_stats __initdata
= {
990 .stat_start
= function_stat_start
,
991 .stat_next
= function_stat_next
,
992 .stat_cmp
= function_stat_cmp
,
993 .stat_headers
= function_stat_headers
,
994 .stat_show
= function_stat_show
997 static __init
void ftrace_profile_debugfs(struct dentry
*d_tracer
)
999 struct ftrace_profile_stat
*stat
;
1000 struct dentry
*entry
;
1005 for_each_possible_cpu(cpu
) {
1006 stat
= &per_cpu(ftrace_profile_stats
, cpu
);
1008 /* allocate enough for function name + cpu number */
1009 name
= kmalloc(32, GFP_KERNEL
);
1012 * The files created are permanent, if something happens
1013 * we still do not free memory.
1016 "Could not allocate stat file for cpu %d\n",
1020 stat
->stat
= function_stats
;
1021 snprintf(name
, 32, "function%d", cpu
);
1022 stat
->stat
.name
= name
;
1023 ret
= register_stat_tracer(&stat
->stat
);
1026 "Could not register function stat for cpu %d\n",
1033 entry
= debugfs_create_file("function_profile_enabled", 0644,
1034 d_tracer
, NULL
, &ftrace_profile_fops
);
1036 pr_warning("Could not create debugfs "
1037 "'function_profile_enabled' entry\n");
1040 #else /* CONFIG_FUNCTION_PROFILER */
1041 static __init
void ftrace_profile_debugfs(struct dentry
*d_tracer
)
1044 #endif /* CONFIG_FUNCTION_PROFILER */
1046 static struct pid
* const ftrace_swapper_pid
= &init_struct_pid
;
1049 ftrace_filter_lseek(struct file
*file
, loff_t offset
, int whence
)
1053 if (file
->f_mode
& FMODE_READ
)
1054 ret
= seq_lseek(file
, offset
, whence
);
1056 file
->f_pos
= ret
= 1;
1061 #ifdef CONFIG_DYNAMIC_FTRACE
1063 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1064 # error Dynamic ftrace depends on MCOUNT_RECORD
1067 static struct hlist_head ftrace_func_hash
[FTRACE_FUNC_HASHSIZE
] __read_mostly
;
1069 struct ftrace_func_probe
{
1070 struct hlist_node node
;
1071 struct ftrace_probe_ops
*ops
;
1072 unsigned long flags
;
1075 struct list_head free_list
;
1078 struct ftrace_func_entry
{
1079 struct hlist_node hlist
;
1083 struct ftrace_hash
{
1084 unsigned long size_bits
;
1085 struct hlist_head
*buckets
;
1086 unsigned long count
;
1087 struct rcu_head rcu
;
1091 * We make these constant because no one should touch them,
1092 * but they are used as the default "empty hash", to avoid allocating
1093 * it all the time. These are in a read only section such that if
1094 * anyone does try to modify it, it will cause an exception.
1096 static const struct hlist_head empty_buckets
[1];
1097 static const struct ftrace_hash empty_hash
= {
1098 .buckets
= (struct hlist_head
*)empty_buckets
,
1100 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1102 static struct ftrace_ops global_ops
= {
1103 .func
= ftrace_stub
,
1104 .notrace_hash
= EMPTY_HASH
,
1105 .filter_hash
= EMPTY_HASH
,
1106 .flags
= FTRACE_OPS_FL_RECURSION_SAFE
,
1109 static DEFINE_MUTEX(ftrace_regex_lock
);
1111 struct ftrace_page
{
1112 struct ftrace_page
*next
;
1113 struct dyn_ftrace
*records
;
1118 static struct ftrace_page
*ftrace_new_pgs
;
1120 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1121 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1123 /* estimate from running different kernels */
1124 #define NR_TO_INIT 10000
1126 static struct ftrace_page
*ftrace_pages_start
;
1127 static struct ftrace_page
*ftrace_pages
;
1129 static bool ftrace_hash_empty(struct ftrace_hash
*hash
)
1131 return !hash
|| !hash
->count
;
1134 static struct ftrace_func_entry
*
1135 ftrace_lookup_ip(struct ftrace_hash
*hash
, unsigned long ip
)
1138 struct ftrace_func_entry
*entry
;
1139 struct hlist_head
*hhd
;
1141 if (ftrace_hash_empty(hash
))
1144 if (hash
->size_bits
> 0)
1145 key
= hash_long(ip
, hash
->size_bits
);
1149 hhd
= &hash
->buckets
[key
];
1151 hlist_for_each_entry_rcu(entry
, hhd
, hlist
) {
1152 if (entry
->ip
== ip
)
1158 static void __add_hash_entry(struct ftrace_hash
*hash
,
1159 struct ftrace_func_entry
*entry
)
1161 struct hlist_head
*hhd
;
1164 if (hash
->size_bits
)
1165 key
= hash_long(entry
->ip
, hash
->size_bits
);
1169 hhd
= &hash
->buckets
[key
];
1170 hlist_add_head(&entry
->hlist
, hhd
);
1174 static int add_hash_entry(struct ftrace_hash
*hash
, unsigned long ip
)
1176 struct ftrace_func_entry
*entry
;
1178 entry
= kmalloc(sizeof(*entry
), GFP_KERNEL
);
1183 __add_hash_entry(hash
, entry
);
1189 free_hash_entry(struct ftrace_hash
*hash
,
1190 struct ftrace_func_entry
*entry
)
1192 hlist_del(&entry
->hlist
);
1198 remove_hash_entry(struct ftrace_hash
*hash
,
1199 struct ftrace_func_entry
*entry
)
1201 hlist_del(&entry
->hlist
);
1205 static void ftrace_hash_clear(struct ftrace_hash
*hash
)
1207 struct hlist_head
*hhd
;
1208 struct hlist_node
*tn
;
1209 struct ftrace_func_entry
*entry
;
1210 int size
= 1 << hash
->size_bits
;
1216 for (i
= 0; i
< size
; i
++) {
1217 hhd
= &hash
->buckets
[i
];
1218 hlist_for_each_entry_safe(entry
, tn
, hhd
, hlist
)
1219 free_hash_entry(hash
, entry
);
1221 FTRACE_WARN_ON(hash
->count
);
1224 static void free_ftrace_hash(struct ftrace_hash
*hash
)
1226 if (!hash
|| hash
== EMPTY_HASH
)
1228 ftrace_hash_clear(hash
);
1229 kfree(hash
->buckets
);
1233 static void __free_ftrace_hash_rcu(struct rcu_head
*rcu
)
1235 struct ftrace_hash
*hash
;
1237 hash
= container_of(rcu
, struct ftrace_hash
, rcu
);
1238 free_ftrace_hash(hash
);
1241 static void free_ftrace_hash_rcu(struct ftrace_hash
*hash
)
1243 if (!hash
|| hash
== EMPTY_HASH
)
1245 call_rcu_sched(&hash
->rcu
, __free_ftrace_hash_rcu
);
1248 void ftrace_free_filter(struct ftrace_ops
*ops
)
1250 free_ftrace_hash(ops
->filter_hash
);
1251 free_ftrace_hash(ops
->notrace_hash
);
1254 static struct ftrace_hash
*alloc_ftrace_hash(int size_bits
)
1256 struct ftrace_hash
*hash
;
1259 hash
= kzalloc(sizeof(*hash
), GFP_KERNEL
);
1263 size
= 1 << size_bits
;
1264 hash
->buckets
= kcalloc(size
, sizeof(*hash
->buckets
), GFP_KERNEL
);
1266 if (!hash
->buckets
) {
1271 hash
->size_bits
= size_bits
;
1276 static struct ftrace_hash
*
1277 alloc_and_copy_ftrace_hash(int size_bits
, struct ftrace_hash
*hash
)
1279 struct ftrace_func_entry
*entry
;
1280 struct ftrace_hash
*new_hash
;
1285 new_hash
= alloc_ftrace_hash(size_bits
);
1290 if (ftrace_hash_empty(hash
))
1293 size
= 1 << hash
->size_bits
;
1294 for (i
= 0; i
< size
; i
++) {
1295 hlist_for_each_entry(entry
, &hash
->buckets
[i
], hlist
) {
1296 ret
= add_hash_entry(new_hash
, entry
->ip
);
1302 FTRACE_WARN_ON(new_hash
->count
!= hash
->count
);
1307 free_ftrace_hash(new_hash
);
1312 ftrace_hash_rec_disable(struct ftrace_ops
*ops
, int filter_hash
);
1314 ftrace_hash_rec_enable(struct ftrace_ops
*ops
, int filter_hash
);
1317 ftrace_hash_move(struct ftrace_ops
*ops
, int enable
,
1318 struct ftrace_hash
**dst
, struct ftrace_hash
*src
)
1320 struct ftrace_func_entry
*entry
;
1321 struct hlist_node
*tn
;
1322 struct hlist_head
*hhd
;
1323 struct ftrace_hash
*old_hash
;
1324 struct ftrace_hash
*new_hash
;
1325 int size
= src
->count
;
1331 * Remove the current set, update the hash and add
1334 ftrace_hash_rec_disable(ops
, enable
);
1337 * If the new source is empty, just free dst and assign it
1341 free_ftrace_hash_rcu(*dst
);
1342 rcu_assign_pointer(*dst
, EMPTY_HASH
);
1343 /* still need to update the function records */
1349 * Make the hash size about 1/2 the # found
1351 for (size
/= 2; size
; size
>>= 1)
1354 /* Don't allocate too much */
1355 if (bits
> FTRACE_HASH_MAX_BITS
)
1356 bits
= FTRACE_HASH_MAX_BITS
;
1359 new_hash
= alloc_ftrace_hash(bits
);
1363 size
= 1 << src
->size_bits
;
1364 for (i
= 0; i
< size
; i
++) {
1365 hhd
= &src
->buckets
[i
];
1366 hlist_for_each_entry_safe(entry
, tn
, hhd
, hlist
) {
1367 remove_hash_entry(src
, entry
);
1368 __add_hash_entry(new_hash
, entry
);
1373 rcu_assign_pointer(*dst
, new_hash
);
1374 free_ftrace_hash_rcu(old_hash
);
1379 * Enable regardless of ret:
1380 * On success, we enable the new hash.
1381 * On failure, we re-enable the original hash.
1383 ftrace_hash_rec_enable(ops
, enable
);
1389 * Test the hashes for this ops to see if we want to call
1390 * the ops->func or not.
1392 * It's a match if the ip is in the ops->filter_hash or
1393 * the filter_hash does not exist or is empty,
1395 * the ip is not in the ops->notrace_hash.
1397 * This needs to be called with preemption disabled as
1398 * the hashes are freed with call_rcu_sched().
1401 ftrace_ops_test(struct ftrace_ops
*ops
, unsigned long ip
)
1403 struct ftrace_hash
*filter_hash
;
1404 struct ftrace_hash
*notrace_hash
;
1407 filter_hash
= rcu_dereference_raw(ops
->filter_hash
);
1408 notrace_hash
= rcu_dereference_raw(ops
->notrace_hash
);
1410 if ((ftrace_hash_empty(filter_hash
) ||
1411 ftrace_lookup_ip(filter_hash
, ip
)) &&
1412 (ftrace_hash_empty(notrace_hash
) ||
1413 !ftrace_lookup_ip(notrace_hash
, ip
)))
1422 * This is a double for. Do not use 'break' to break out of the loop,
1423 * you must use a goto.
1425 #define do_for_each_ftrace_rec(pg, rec) \
1426 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1428 for (_____i = 0; _____i < pg->index; _____i++) { \
1429 rec = &pg->records[_____i];
1431 #define while_for_each_ftrace_rec() \
1436 static int ftrace_cmp_recs(const void *a
, const void *b
)
1438 const struct dyn_ftrace
*key
= a
;
1439 const struct dyn_ftrace
*rec
= b
;
1441 if (key
->flags
< rec
->ip
)
1443 if (key
->ip
>= rec
->ip
+ MCOUNT_INSN_SIZE
)
1448 static unsigned long ftrace_location_range(unsigned long start
, unsigned long end
)
1450 struct ftrace_page
*pg
;
1451 struct dyn_ftrace
*rec
;
1452 struct dyn_ftrace key
;
1455 key
.flags
= end
; /* overload flags, as it is unsigned long */
1457 for (pg
= ftrace_pages_start
; pg
; pg
= pg
->next
) {
1458 if (end
< pg
->records
[0].ip
||
1459 start
>= (pg
->records
[pg
->index
- 1].ip
+ MCOUNT_INSN_SIZE
))
1461 rec
= bsearch(&key
, pg
->records
, pg
->index
,
1462 sizeof(struct dyn_ftrace
),
1472 * ftrace_location - return true if the ip giving is a traced location
1473 * @ip: the instruction pointer to check
1475 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1476 * That is, the instruction that is either a NOP or call to
1477 * the function tracer. It checks the ftrace internal tables to
1478 * determine if the address belongs or not.
1480 unsigned long ftrace_location(unsigned long ip
)
1482 return ftrace_location_range(ip
, ip
);
1486 * ftrace_text_reserved - return true if range contains an ftrace location
1487 * @start: start of range to search
1488 * @end: end of range to search (inclusive). @end points to the last byte to check.
1490 * Returns 1 if @start and @end contains a ftrace location.
1491 * That is, the instruction that is either a NOP or call to
1492 * the function tracer. It checks the ftrace internal tables to
1493 * determine if the address belongs or not.
1495 int ftrace_text_reserved(void *start
, void *end
)
1499 ret
= ftrace_location_range((unsigned long)start
,
1500 (unsigned long)end
);
1505 static void __ftrace_hash_rec_update(struct ftrace_ops
*ops
,
1509 struct ftrace_hash
*hash
;
1510 struct ftrace_hash
*other_hash
;
1511 struct ftrace_page
*pg
;
1512 struct dyn_ftrace
*rec
;
1516 /* Only update if the ops has been registered */
1517 if (!(ops
->flags
& FTRACE_OPS_FL_ENABLED
))
1521 * In the filter_hash case:
1522 * If the count is zero, we update all records.
1523 * Otherwise we just update the items in the hash.
1525 * In the notrace_hash case:
1526 * We enable the update in the hash.
1527 * As disabling notrace means enabling the tracing,
1528 * and enabling notrace means disabling, the inc variable
1532 hash
= ops
->filter_hash
;
1533 other_hash
= ops
->notrace_hash
;
1534 if (ftrace_hash_empty(hash
))
1538 hash
= ops
->notrace_hash
;
1539 other_hash
= ops
->filter_hash
;
1541 * If the notrace hash has no items,
1542 * then there's nothing to do.
1544 if (ftrace_hash_empty(hash
))
1548 do_for_each_ftrace_rec(pg
, rec
) {
1549 int in_other_hash
= 0;
1555 * Only the filter_hash affects all records.
1556 * Update if the record is not in the notrace hash.
1558 if (!other_hash
|| !ftrace_lookup_ip(other_hash
, rec
->ip
))
1561 in_hash
= !!ftrace_lookup_ip(hash
, rec
->ip
);
1562 in_other_hash
= !!ftrace_lookup_ip(other_hash
, rec
->ip
);
1567 if (filter_hash
&& in_hash
&& !in_other_hash
)
1569 else if (!filter_hash
&& in_hash
&&
1570 (in_other_hash
|| ftrace_hash_empty(other_hash
)))
1578 if (FTRACE_WARN_ON((rec
->flags
& ~FTRACE_FL_MASK
) == FTRACE_REF_MAX
))
1581 * If any ops wants regs saved for this function
1582 * then all ops will get saved regs.
1584 if (ops
->flags
& FTRACE_OPS_FL_SAVE_REGS
)
1585 rec
->flags
|= FTRACE_FL_REGS
;
1587 if (FTRACE_WARN_ON((rec
->flags
& ~FTRACE_FL_MASK
) == 0))
1592 /* Shortcut, if we handled all records, we are done. */
1593 if (!all
&& count
== hash
->count
)
1595 } while_for_each_ftrace_rec();
1598 static void ftrace_hash_rec_disable(struct ftrace_ops
*ops
,
1601 __ftrace_hash_rec_update(ops
, filter_hash
, 0);
1604 static void ftrace_hash_rec_enable(struct ftrace_ops
*ops
,
1607 __ftrace_hash_rec_update(ops
, filter_hash
, 1);
1610 static void print_ip_ins(const char *fmt
, unsigned char *p
)
1614 printk(KERN_CONT
"%s", fmt
);
1616 for (i
= 0; i
< MCOUNT_INSN_SIZE
; i
++)
1617 printk(KERN_CONT
"%s%02x", i
? ":" : "", p
[i
]);
1621 * ftrace_bug - report and shutdown function tracer
1622 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1623 * @ip: The address that failed
1625 * The arch code that enables or disables the function tracing
1626 * can call ftrace_bug() when it has detected a problem in
1627 * modifying the code. @failed should be one of either:
1628 * EFAULT - if the problem happens on reading the @ip address
1629 * EINVAL - if what is read at @ip is not what was expected
1630 * EPERM - if the problem happens on writting to the @ip address
1632 void ftrace_bug(int failed
, unsigned long ip
)
1636 FTRACE_WARN_ON_ONCE(1);
1637 pr_info("ftrace faulted on modifying ");
1641 FTRACE_WARN_ON_ONCE(1);
1642 pr_info("ftrace failed to modify ");
1644 print_ip_ins(" actual: ", (unsigned char *)ip
);
1645 printk(KERN_CONT
"\n");
1648 FTRACE_WARN_ON_ONCE(1);
1649 pr_info("ftrace faulted on writing ");
1653 FTRACE_WARN_ON_ONCE(1);
1654 pr_info("ftrace faulted on unknown error ");
1659 static int ftrace_check_record(struct dyn_ftrace
*rec
, int enable
, int update
)
1661 unsigned long flag
= 0UL;
1664 * If we are updating calls:
1666 * If the record has a ref count, then we need to enable it
1667 * because someone is using it.
1669 * Otherwise we make sure its disabled.
1671 * If we are disabling calls, then disable all records that
1674 if (enable
&& (rec
->flags
& ~FTRACE_FL_MASK
))
1675 flag
= FTRACE_FL_ENABLED
;
1678 * If enabling and the REGS flag does not match the REGS_EN, then
1679 * do not ignore this record. Set flags to fail the compare against
1683 (!(rec
->flags
& FTRACE_FL_REGS
) != !(rec
->flags
& FTRACE_FL_REGS_EN
)))
1684 flag
|= FTRACE_FL_REGS
;
1686 /* If the state of this record hasn't changed, then do nothing */
1687 if ((rec
->flags
& FTRACE_FL_ENABLED
) == flag
)
1688 return FTRACE_UPDATE_IGNORE
;
1691 /* Save off if rec is being enabled (for return value) */
1692 flag
^= rec
->flags
& FTRACE_FL_ENABLED
;
1695 rec
->flags
|= FTRACE_FL_ENABLED
;
1696 if (flag
& FTRACE_FL_REGS
) {
1697 if (rec
->flags
& FTRACE_FL_REGS
)
1698 rec
->flags
|= FTRACE_FL_REGS_EN
;
1700 rec
->flags
&= ~FTRACE_FL_REGS_EN
;
1705 * If this record is being updated from a nop, then
1706 * return UPDATE_MAKE_CALL.
1707 * Otherwise, if the EN flag is set, then return
1708 * UPDATE_MODIFY_CALL_REGS to tell the caller to convert
1709 * from the non-save regs, to a save regs function.
1711 * return UPDATE_MODIFY_CALL to tell the caller to convert
1712 * from the save regs, to a non-save regs function.
1714 if (flag
& FTRACE_FL_ENABLED
)
1715 return FTRACE_UPDATE_MAKE_CALL
;
1716 else if (rec
->flags
& FTRACE_FL_REGS_EN
)
1717 return FTRACE_UPDATE_MODIFY_CALL_REGS
;
1719 return FTRACE_UPDATE_MODIFY_CALL
;
1723 /* If there's no more users, clear all flags */
1724 if (!(rec
->flags
& ~FTRACE_FL_MASK
))
1727 /* Just disable the record (keep REGS state) */
1728 rec
->flags
&= ~FTRACE_FL_ENABLED
;
1731 return FTRACE_UPDATE_MAKE_NOP
;
1735 * ftrace_update_record, set a record that now is tracing or not
1736 * @rec: the record to update
1737 * @enable: set to 1 if the record is tracing, zero to force disable
1739 * The records that represent all functions that can be traced need
1740 * to be updated when tracing has been enabled.
1742 int ftrace_update_record(struct dyn_ftrace
*rec
, int enable
)
1744 return ftrace_check_record(rec
, enable
, 1);
1748 * ftrace_test_record, check if the record has been enabled or not
1749 * @rec: the record to test
1750 * @enable: set to 1 to check if enabled, 0 if it is disabled
1752 * The arch code may need to test if a record is already set to
1753 * tracing to determine how to modify the function code that it
1756 int ftrace_test_record(struct dyn_ftrace
*rec
, int enable
)
1758 return ftrace_check_record(rec
, enable
, 0);
1762 __ftrace_replace_code(struct dyn_ftrace
*rec
, int enable
)
1764 unsigned long ftrace_old_addr
;
1765 unsigned long ftrace_addr
;
1768 ret
= ftrace_update_record(rec
, enable
);
1770 if (rec
->flags
& FTRACE_FL_REGS
)
1771 ftrace_addr
= (unsigned long)FTRACE_REGS_ADDR
;
1773 ftrace_addr
= (unsigned long)FTRACE_ADDR
;
1776 case FTRACE_UPDATE_IGNORE
:
1779 case FTRACE_UPDATE_MAKE_CALL
:
1780 return ftrace_make_call(rec
, ftrace_addr
);
1782 case FTRACE_UPDATE_MAKE_NOP
:
1783 return ftrace_make_nop(NULL
, rec
, ftrace_addr
);
1785 case FTRACE_UPDATE_MODIFY_CALL_REGS
:
1786 case FTRACE_UPDATE_MODIFY_CALL
:
1787 if (rec
->flags
& FTRACE_FL_REGS
)
1788 ftrace_old_addr
= (unsigned long)FTRACE_ADDR
;
1790 ftrace_old_addr
= (unsigned long)FTRACE_REGS_ADDR
;
1792 return ftrace_modify_call(rec
, ftrace_old_addr
, ftrace_addr
);
1795 return -1; /* unknow ftrace bug */
1798 void __weak
ftrace_replace_code(int enable
)
1800 struct dyn_ftrace
*rec
;
1801 struct ftrace_page
*pg
;
1804 if (unlikely(ftrace_disabled
))
1807 do_for_each_ftrace_rec(pg
, rec
) {
1808 failed
= __ftrace_replace_code(rec
, enable
);
1810 ftrace_bug(failed
, rec
->ip
);
1811 /* Stop processing */
1814 } while_for_each_ftrace_rec();
1817 struct ftrace_rec_iter
{
1818 struct ftrace_page
*pg
;
1823 * ftrace_rec_iter_start, start up iterating over traced functions
1825 * Returns an iterator handle that is used to iterate over all
1826 * the records that represent address locations where functions
1829 * May return NULL if no records are available.
1831 struct ftrace_rec_iter
*ftrace_rec_iter_start(void)
1834 * We only use a single iterator.
1835 * Protected by the ftrace_lock mutex.
1837 static struct ftrace_rec_iter ftrace_rec_iter
;
1838 struct ftrace_rec_iter
*iter
= &ftrace_rec_iter
;
1840 iter
->pg
= ftrace_pages_start
;
1843 /* Could have empty pages */
1844 while (iter
->pg
&& !iter
->pg
->index
)
1845 iter
->pg
= iter
->pg
->next
;
1854 * ftrace_rec_iter_next, get the next record to process.
1855 * @iter: The handle to the iterator.
1857 * Returns the next iterator after the given iterator @iter.
1859 struct ftrace_rec_iter
*ftrace_rec_iter_next(struct ftrace_rec_iter
*iter
)
1863 if (iter
->index
>= iter
->pg
->index
) {
1864 iter
->pg
= iter
->pg
->next
;
1867 /* Could have empty pages */
1868 while (iter
->pg
&& !iter
->pg
->index
)
1869 iter
->pg
= iter
->pg
->next
;
1879 * ftrace_rec_iter_record, get the record at the iterator location
1880 * @iter: The current iterator location
1882 * Returns the record that the current @iter is at.
1884 struct dyn_ftrace
*ftrace_rec_iter_record(struct ftrace_rec_iter
*iter
)
1886 return &iter
->pg
->records
[iter
->index
];
1890 ftrace_code_disable(struct module
*mod
, struct dyn_ftrace
*rec
)
1897 if (unlikely(ftrace_disabled
))
1900 ret
= ftrace_make_nop(mod
, rec
, MCOUNT_ADDR
);
1902 ftrace_bug(ret
, ip
);
1909 * archs can override this function if they must do something
1910 * before the modifying code is performed.
1912 int __weak
ftrace_arch_code_modify_prepare(void)
1918 * archs can override this function if they must do something
1919 * after the modifying code is performed.
1921 int __weak
ftrace_arch_code_modify_post_process(void)
1926 void ftrace_modify_all_code(int command
)
1928 if (command
& FTRACE_UPDATE_CALLS
)
1929 ftrace_replace_code(1);
1930 else if (command
& FTRACE_DISABLE_CALLS
)
1931 ftrace_replace_code(0);
1933 if (command
& FTRACE_UPDATE_TRACE_FUNC
)
1934 ftrace_update_ftrace_func(ftrace_trace_function
);
1936 if (command
& FTRACE_START_FUNC_RET
)
1937 ftrace_enable_ftrace_graph_caller();
1938 else if (command
& FTRACE_STOP_FUNC_RET
)
1939 ftrace_disable_ftrace_graph_caller();
1942 static int __ftrace_modify_code(void *data
)
1944 int *command
= data
;
1946 ftrace_modify_all_code(*command
);
1952 * ftrace_run_stop_machine, go back to the stop machine method
1953 * @command: The command to tell ftrace what to do
1955 * If an arch needs to fall back to the stop machine method, the
1956 * it can call this function.
1958 void ftrace_run_stop_machine(int command
)
1960 stop_machine(__ftrace_modify_code
, &command
, NULL
);
1964 * arch_ftrace_update_code, modify the code to trace or not trace
1965 * @command: The command that needs to be done
1967 * Archs can override this function if it does not need to
1968 * run stop_machine() to modify code.
1970 void __weak
arch_ftrace_update_code(int command
)
1972 ftrace_run_stop_machine(command
);
1975 static void ftrace_run_update_code(int command
)
1979 ret
= ftrace_arch_code_modify_prepare();
1980 FTRACE_WARN_ON(ret
);
1984 * Do not call function tracer while we update the code.
1985 * We are in stop machine.
1987 function_trace_stop
++;
1990 * By default we use stop_machine() to modify the code.
1991 * But archs can do what ever they want as long as it
1992 * is safe. The stop_machine() is the safest, but also
1993 * produces the most overhead.
1995 arch_ftrace_update_code(command
);
1997 function_trace_stop
--;
1999 ret
= ftrace_arch_code_modify_post_process();
2000 FTRACE_WARN_ON(ret
);
2003 static ftrace_func_t saved_ftrace_func
;
2004 static int ftrace_start_up
;
2005 static int global_start_up
;
2007 static void ftrace_startup_enable(int command
)
2009 if (saved_ftrace_func
!= ftrace_trace_function
) {
2010 saved_ftrace_func
= ftrace_trace_function
;
2011 command
|= FTRACE_UPDATE_TRACE_FUNC
;
2014 if (!command
|| !ftrace_enabled
)
2017 ftrace_run_update_code(command
);
2020 static int ftrace_startup(struct ftrace_ops
*ops
, int command
)
2022 bool hash_enable
= true;
2024 if (unlikely(ftrace_disabled
))
2028 command
|= FTRACE_UPDATE_CALLS
;
2030 /* ops marked global share the filter hashes */
2031 if (ops
->flags
& FTRACE_OPS_FL_GLOBAL
) {
2033 /* Don't update hash if global is already set */
2034 if (global_start_up
)
2035 hash_enable
= false;
2039 ops
->flags
|= FTRACE_OPS_FL_ENABLED
;
2041 ftrace_hash_rec_enable(ops
, 1);
2043 ftrace_startup_enable(command
);
2048 static void ftrace_shutdown(struct ftrace_ops
*ops
, int command
)
2050 bool hash_disable
= true;
2052 if (unlikely(ftrace_disabled
))
2057 * Just warn in case of unbalance, no need to kill ftrace, it's not
2058 * critical but the ftrace_call callers may be never nopped again after
2059 * further ftrace uses.
2061 WARN_ON_ONCE(ftrace_start_up
< 0);
2063 if (ops
->flags
& FTRACE_OPS_FL_GLOBAL
) {
2066 WARN_ON_ONCE(global_start_up
< 0);
2067 /* Don't update hash if global still has users */
2068 if (global_start_up
) {
2069 WARN_ON_ONCE(!ftrace_start_up
);
2070 hash_disable
= false;
2075 ftrace_hash_rec_disable(ops
, 1);
2077 if (ops
!= &global_ops
|| !global_start_up
)
2078 ops
->flags
&= ~FTRACE_OPS_FL_ENABLED
;
2080 command
|= FTRACE_UPDATE_CALLS
;
2082 if (saved_ftrace_func
!= ftrace_trace_function
) {
2083 saved_ftrace_func
= ftrace_trace_function
;
2084 command
|= FTRACE_UPDATE_TRACE_FUNC
;
2087 if (!command
|| !ftrace_enabled
)
2090 ftrace_run_update_code(command
);
2093 static void ftrace_startup_sysctl(void)
2095 if (unlikely(ftrace_disabled
))
2098 /* Force update next time */
2099 saved_ftrace_func
= NULL
;
2100 /* ftrace_start_up is true if we want ftrace running */
2101 if (ftrace_start_up
)
2102 ftrace_run_update_code(FTRACE_UPDATE_CALLS
);
2105 static void ftrace_shutdown_sysctl(void)
2107 if (unlikely(ftrace_disabled
))
2110 /* ftrace_start_up is true if ftrace is running */
2111 if (ftrace_start_up
)
2112 ftrace_run_update_code(FTRACE_DISABLE_CALLS
);
2115 static cycle_t ftrace_update_time
;
2116 static unsigned long ftrace_update_cnt
;
2117 unsigned long ftrace_update_tot_cnt
;
2119 static int ops_traces_mod(struct ftrace_ops
*ops
)
2121 struct ftrace_hash
*hash
;
2123 hash
= ops
->filter_hash
;
2124 return ftrace_hash_empty(hash
);
2127 static int ftrace_update_code(struct module
*mod
)
2129 struct ftrace_page
*pg
;
2130 struct dyn_ftrace
*p
;
2131 cycle_t start
, stop
;
2132 unsigned long ref
= 0;
2136 * When adding a module, we need to check if tracers are
2137 * currently enabled and if they are set to trace all functions.
2138 * If they are, we need to enable the module functions as well
2139 * as update the reference counts for those function records.
2142 struct ftrace_ops
*ops
;
2144 for (ops
= ftrace_ops_list
;
2145 ops
!= &ftrace_list_end
; ops
= ops
->next
) {
2146 if (ops
->flags
& FTRACE_OPS_FL_ENABLED
&&
2147 ops_traces_mod(ops
))
2152 start
= ftrace_now(raw_smp_processor_id());
2153 ftrace_update_cnt
= 0;
2155 for (pg
= ftrace_new_pgs
; pg
; pg
= pg
->next
) {
2157 for (i
= 0; i
< pg
->index
; i
++) {
2158 /* If something went wrong, bail without enabling anything */
2159 if (unlikely(ftrace_disabled
))
2162 p
= &pg
->records
[i
];
2166 * Do the initial record conversion from mcount jump
2167 * to the NOP instructions.
2169 if (!ftrace_code_disable(mod
, p
))
2172 ftrace_update_cnt
++;
2175 * If the tracing is enabled, go ahead and enable the record.
2177 * The reason not to enable the record immediatelly is the
2178 * inherent check of ftrace_make_nop/ftrace_make_call for
2179 * correct previous instructions. Making first the NOP
2180 * conversion puts the module to the correct state, thus
2181 * passing the ftrace_make_call check.
2183 if (ftrace_start_up
&& ref
) {
2184 int failed
= __ftrace_replace_code(p
, 1);
2186 ftrace_bug(failed
, p
->ip
);
2191 ftrace_new_pgs
= NULL
;
2193 stop
= ftrace_now(raw_smp_processor_id());
2194 ftrace_update_time
= stop
- start
;
2195 ftrace_update_tot_cnt
+= ftrace_update_cnt
;
2200 static int ftrace_allocate_records(struct ftrace_page
*pg
, int count
)
2205 if (WARN_ON(!count
))
2208 order
= get_count_order(DIV_ROUND_UP(count
, ENTRIES_PER_PAGE
));
2211 * We want to fill as much as possible. No more than a page
2214 while ((PAGE_SIZE
<< order
) / ENTRY_SIZE
>= count
+ ENTRIES_PER_PAGE
)
2218 pg
->records
= (void *)__get_free_pages(GFP_KERNEL
| __GFP_ZERO
, order
);
2221 /* if we can't allocate this size, try something smaller */
2228 cnt
= (PAGE_SIZE
<< order
) / ENTRY_SIZE
;
2237 static struct ftrace_page
*
2238 ftrace_allocate_pages(unsigned long num_to_init
)
2240 struct ftrace_page
*start_pg
;
2241 struct ftrace_page
*pg
;
2248 start_pg
= pg
= kzalloc(sizeof(*pg
), GFP_KERNEL
);
2253 * Try to allocate as much as possible in one continues
2254 * location that fills in all of the space. We want to
2255 * waste as little space as possible.
2258 cnt
= ftrace_allocate_records(pg
, num_to_init
);
2266 pg
->next
= kzalloc(sizeof(*pg
), GFP_KERNEL
);
2277 order
= get_count_order(pg
->size
/ ENTRIES_PER_PAGE
);
2278 free_pages((unsigned long)pg
->records
, order
);
2279 start_pg
= pg
->next
;
2283 pr_info("ftrace: FAILED to allocate memory for functions\n");
2287 static int __init
ftrace_dyn_table_alloc(unsigned long num_to_init
)
2292 pr_info("ftrace: No functions to be traced?\n");
2296 cnt
= num_to_init
/ ENTRIES_PER_PAGE
;
2297 pr_info("ftrace: allocating %ld entries in %d pages\n",
2298 num_to_init
, cnt
+ 1);
2303 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
2305 struct ftrace_iterator
{
2308 struct ftrace_page
*pg
;
2309 struct dyn_ftrace
*func
;
2310 struct ftrace_func_probe
*probe
;
2311 struct trace_parser parser
;
2312 struct ftrace_hash
*hash
;
2313 struct ftrace_ops
*ops
;
2320 t_hash_next(struct seq_file
*m
, loff_t
*pos
)
2322 struct ftrace_iterator
*iter
= m
->private;
2323 struct hlist_node
*hnd
= NULL
;
2324 struct hlist_head
*hhd
;
2330 hnd
= &iter
->probe
->node
;
2332 if (iter
->hidx
>= FTRACE_FUNC_HASHSIZE
)
2335 hhd
= &ftrace_func_hash
[iter
->hidx
];
2337 if (hlist_empty(hhd
)) {
2353 if (WARN_ON_ONCE(!hnd
))
2356 iter
->probe
= hlist_entry(hnd
, struct ftrace_func_probe
, node
);
2361 static void *t_hash_start(struct seq_file
*m
, loff_t
*pos
)
2363 struct ftrace_iterator
*iter
= m
->private;
2367 if (!(iter
->flags
& FTRACE_ITER_DO_HASH
))
2370 if (iter
->func_pos
> *pos
)
2374 for (l
= 0; l
<= (*pos
- iter
->func_pos
); ) {
2375 p
= t_hash_next(m
, &l
);
2382 /* Only set this if we have an item */
2383 iter
->flags
|= FTRACE_ITER_HASH
;
2389 t_hash_show(struct seq_file
*m
, struct ftrace_iterator
*iter
)
2391 struct ftrace_func_probe
*rec
;
2394 if (WARN_ON_ONCE(!rec
))
2397 if (rec
->ops
->print
)
2398 return rec
->ops
->print(m
, rec
->ip
, rec
->ops
, rec
->data
);
2400 seq_printf(m
, "%ps:%ps", (void *)rec
->ip
, (void *)rec
->ops
->func
);
2403 seq_printf(m
, ":%p", rec
->data
);
2410 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
2412 struct ftrace_iterator
*iter
= m
->private;
2413 struct ftrace_ops
*ops
= iter
->ops
;
2414 struct dyn_ftrace
*rec
= NULL
;
2416 if (unlikely(ftrace_disabled
))
2419 if (iter
->flags
& FTRACE_ITER_HASH
)
2420 return t_hash_next(m
, pos
);
2423 iter
->pos
= iter
->func_pos
= *pos
;
2425 if (iter
->flags
& FTRACE_ITER_PRINTALL
)
2426 return t_hash_start(m
, pos
);
2429 if (iter
->idx
>= iter
->pg
->index
) {
2430 if (iter
->pg
->next
) {
2431 iter
->pg
= iter
->pg
->next
;
2436 rec
= &iter
->pg
->records
[iter
->idx
++];
2437 if (((iter
->flags
& FTRACE_ITER_FILTER
) &&
2438 !(ftrace_lookup_ip(ops
->filter_hash
, rec
->ip
))) ||
2440 ((iter
->flags
& FTRACE_ITER_NOTRACE
) &&
2441 !ftrace_lookup_ip(ops
->notrace_hash
, rec
->ip
)) ||
2443 ((iter
->flags
& FTRACE_ITER_ENABLED
) &&
2444 !(rec
->flags
& ~FTRACE_FL_MASK
))) {
2452 return t_hash_start(m
, pos
);
2459 static void reset_iter_read(struct ftrace_iterator
*iter
)
2463 iter
->flags
&= ~(FTRACE_ITER_PRINTALL
| FTRACE_ITER_HASH
);
2466 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
2468 struct ftrace_iterator
*iter
= m
->private;
2469 struct ftrace_ops
*ops
= iter
->ops
;
2473 mutex_lock(&ftrace_lock
);
2475 if (unlikely(ftrace_disabled
))
2479 * If an lseek was done, then reset and start from beginning.
2481 if (*pos
< iter
->pos
)
2482 reset_iter_read(iter
);
2485 * For set_ftrace_filter reading, if we have the filter
2486 * off, we can short cut and just print out that all
2487 * functions are enabled.
2489 if (iter
->flags
& FTRACE_ITER_FILTER
&&
2490 ftrace_hash_empty(ops
->filter_hash
)) {
2492 return t_hash_start(m
, pos
);
2493 iter
->flags
|= FTRACE_ITER_PRINTALL
;
2494 /* reset in case of seek/pread */
2495 iter
->flags
&= ~FTRACE_ITER_HASH
;
2499 if (iter
->flags
& FTRACE_ITER_HASH
)
2500 return t_hash_start(m
, pos
);
2503 * Unfortunately, we need to restart at ftrace_pages_start
2504 * every time we let go of the ftrace_mutex. This is because
2505 * those pointers can change without the lock.
2507 iter
->pg
= ftrace_pages_start
;
2509 for (l
= 0; l
<= *pos
; ) {
2510 p
= t_next(m
, p
, &l
);
2516 return t_hash_start(m
, pos
);
2521 static void t_stop(struct seq_file
*m
, void *p
)
2523 mutex_unlock(&ftrace_lock
);
2526 static int t_show(struct seq_file
*m
, void *v
)
2528 struct ftrace_iterator
*iter
= m
->private;
2529 struct dyn_ftrace
*rec
;
2531 if (iter
->flags
& FTRACE_ITER_HASH
)
2532 return t_hash_show(m
, iter
);
2534 if (iter
->flags
& FTRACE_ITER_PRINTALL
) {
2535 seq_printf(m
, "#### all functions enabled ####\n");
2544 seq_printf(m
, "%ps", (void *)rec
->ip
);
2545 if (iter
->flags
& FTRACE_ITER_ENABLED
)
2546 seq_printf(m
, " (%ld)%s",
2547 rec
->flags
& ~FTRACE_FL_MASK
,
2548 rec
->flags
& FTRACE_FL_REGS
? " R" : "");
2549 seq_printf(m
, "\n");
2554 static const struct seq_operations show_ftrace_seq_ops
= {
2562 ftrace_avail_open(struct inode
*inode
, struct file
*file
)
2564 struct ftrace_iterator
*iter
;
2566 if (unlikely(ftrace_disabled
))
2569 iter
= __seq_open_private(file
, &show_ftrace_seq_ops
, sizeof(*iter
));
2571 iter
->pg
= ftrace_pages_start
;
2572 iter
->ops
= &global_ops
;
2575 return iter
? 0 : -ENOMEM
;
2579 ftrace_enabled_open(struct inode
*inode
, struct file
*file
)
2581 struct ftrace_iterator
*iter
;
2583 if (unlikely(ftrace_disabled
))
2586 iter
= __seq_open_private(file
, &show_ftrace_seq_ops
, sizeof(*iter
));
2588 iter
->pg
= ftrace_pages_start
;
2589 iter
->flags
= FTRACE_ITER_ENABLED
;
2590 iter
->ops
= &global_ops
;
2593 return iter
? 0 : -ENOMEM
;
2596 static void ftrace_filter_reset(struct ftrace_hash
*hash
)
2598 mutex_lock(&ftrace_lock
);
2599 ftrace_hash_clear(hash
);
2600 mutex_unlock(&ftrace_lock
);
2604 * ftrace_regex_open - initialize function tracer filter files
2605 * @ops: The ftrace_ops that hold the hash filters
2606 * @flag: The type of filter to process
2607 * @inode: The inode, usually passed in to your open routine
2608 * @file: The file, usually passed in to your open routine
2610 * ftrace_regex_open() initializes the filter files for the
2611 * @ops. Depending on @flag it may process the filter hash or
2612 * the notrace hash of @ops. With this called from the open
2613 * routine, you can use ftrace_filter_write() for the write
2614 * routine if @flag has FTRACE_ITER_FILTER set, or
2615 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
2616 * ftrace_filter_lseek() should be used as the lseek routine, and
2617 * release must call ftrace_regex_release().
2620 ftrace_regex_open(struct ftrace_ops
*ops
, int flag
,
2621 struct inode
*inode
, struct file
*file
)
2623 struct ftrace_iterator
*iter
;
2624 struct ftrace_hash
*hash
;
2627 if (unlikely(ftrace_disabled
))
2630 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
2634 if (trace_parser_get_init(&iter
->parser
, FTRACE_BUFF_MAX
)) {
2639 if (flag
& FTRACE_ITER_NOTRACE
)
2640 hash
= ops
->notrace_hash
;
2642 hash
= ops
->filter_hash
;
2647 if (file
->f_mode
& FMODE_WRITE
) {
2648 mutex_lock(&ftrace_lock
);
2649 iter
->hash
= alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
, hash
);
2650 mutex_unlock(&ftrace_lock
);
2653 trace_parser_put(&iter
->parser
);
2659 mutex_lock(&ftrace_regex_lock
);
2661 if ((file
->f_mode
& FMODE_WRITE
) &&
2662 (file
->f_flags
& O_TRUNC
))
2663 ftrace_filter_reset(iter
->hash
);
2665 if (file
->f_mode
& FMODE_READ
) {
2666 iter
->pg
= ftrace_pages_start
;
2668 ret
= seq_open(file
, &show_ftrace_seq_ops
);
2670 struct seq_file
*m
= file
->private_data
;
2674 free_ftrace_hash(iter
->hash
);
2675 trace_parser_put(&iter
->parser
);
2679 file
->private_data
= iter
;
2680 mutex_unlock(&ftrace_regex_lock
);
2686 ftrace_filter_open(struct inode
*inode
, struct file
*file
)
2688 return ftrace_regex_open(&global_ops
,
2689 FTRACE_ITER_FILTER
| FTRACE_ITER_DO_HASH
,
2694 ftrace_notrace_open(struct inode
*inode
, struct file
*file
)
2696 return ftrace_regex_open(&global_ops
, FTRACE_ITER_NOTRACE
,
2700 static int ftrace_match(char *str
, char *regex
, int len
, int type
)
2707 if (strcmp(str
, regex
) == 0)
2710 case MATCH_FRONT_ONLY
:
2711 if (strncmp(str
, regex
, len
) == 0)
2714 case MATCH_MIDDLE_ONLY
:
2715 if (strstr(str
, regex
))
2718 case MATCH_END_ONLY
:
2720 if (slen
>= len
&& memcmp(str
+ slen
- len
, regex
, len
) == 0)
2729 enter_record(struct ftrace_hash
*hash
, struct dyn_ftrace
*rec
, int not)
2731 struct ftrace_func_entry
*entry
;
2734 entry
= ftrace_lookup_ip(hash
, rec
->ip
);
2736 /* Do nothing if it doesn't exist */
2740 free_hash_entry(hash
, entry
);
2742 /* Do nothing if it exists */
2746 ret
= add_hash_entry(hash
, rec
->ip
);
2752 ftrace_match_record(struct dyn_ftrace
*rec
, char *mod
,
2753 char *regex
, int len
, int type
)
2755 char str
[KSYM_SYMBOL_LEN
];
2758 kallsyms_lookup(rec
->ip
, NULL
, NULL
, &modname
, str
);
2761 /* module lookup requires matching the module */
2762 if (!modname
|| strcmp(modname
, mod
))
2765 /* blank search means to match all funcs in the mod */
2770 return ftrace_match(str
, regex
, len
, type
);
2774 match_records(struct ftrace_hash
*hash
, char *buff
,
2775 int len
, char *mod
, int not)
2777 unsigned search_len
= 0;
2778 struct ftrace_page
*pg
;
2779 struct dyn_ftrace
*rec
;
2780 int type
= MATCH_FULL
;
2781 char *search
= buff
;
2786 type
= filter_parse_regex(buff
, len
, &search
, ¬);
2787 search_len
= strlen(search
);
2790 mutex_lock(&ftrace_lock
);
2792 if (unlikely(ftrace_disabled
))
2795 do_for_each_ftrace_rec(pg
, rec
) {
2796 if (ftrace_match_record(rec
, mod
, search
, search_len
, type
)) {
2797 ret
= enter_record(hash
, rec
, not);
2804 } while_for_each_ftrace_rec();
2806 mutex_unlock(&ftrace_lock
);
2812 ftrace_match_records(struct ftrace_hash
*hash
, char *buff
, int len
)
2814 return match_records(hash
, buff
, len
, NULL
, 0);
2818 ftrace_match_module_records(struct ftrace_hash
*hash
, char *buff
, char *mod
)
2822 /* blank or '*' mean the same */
2823 if (strcmp(buff
, "*") == 0)
2826 /* handle the case of 'dont filter this module' */
2827 if (strcmp(buff
, "!") == 0 || strcmp(buff
, "!*") == 0) {
2832 return match_records(hash
, buff
, strlen(buff
), mod
, not);
2836 * We register the module command as a template to show others how
2837 * to register the a command as well.
2841 ftrace_mod_callback(struct ftrace_hash
*hash
,
2842 char *func
, char *cmd
, char *param
, int enable
)
2848 * cmd == 'mod' because we only registered this func
2849 * for the 'mod' ftrace_func_command.
2850 * But if you register one func with multiple commands,
2851 * you can tell which command was used by the cmd
2855 /* we must have a module name */
2859 mod
= strsep(¶m
, ":");
2863 ret
= ftrace_match_module_records(hash
, func
, mod
);
2872 static struct ftrace_func_command ftrace_mod_cmd
= {
2874 .func
= ftrace_mod_callback
,
2877 static int __init
ftrace_mod_cmd_init(void)
2879 return register_ftrace_command(&ftrace_mod_cmd
);
2881 core_initcall(ftrace_mod_cmd_init
);
2883 static void function_trace_probe_call(unsigned long ip
, unsigned long parent_ip
,
2884 struct ftrace_ops
*op
, struct pt_regs
*pt_regs
)
2886 struct ftrace_func_probe
*entry
;
2887 struct hlist_head
*hhd
;
2890 key
= hash_long(ip
, FTRACE_HASH_BITS
);
2892 hhd
= &ftrace_func_hash
[key
];
2894 if (hlist_empty(hhd
))
2898 * Disable preemption for these calls to prevent a RCU grace
2899 * period. This syncs the hash iteration and freeing of items
2900 * on the hash. rcu_read_lock is too dangerous here.
2902 preempt_disable_notrace();
2903 hlist_for_each_entry_rcu(entry
, hhd
, node
) {
2904 if (entry
->ip
== ip
)
2905 entry
->ops
->func(ip
, parent_ip
, &entry
->data
);
2907 preempt_enable_notrace();
2910 static struct ftrace_ops trace_probe_ops __read_mostly
=
2912 .func
= function_trace_probe_call
,
2915 static int ftrace_probe_registered
;
2917 static void __enable_ftrace_function_probe(void)
2922 if (ftrace_probe_registered
)
2925 for (i
= 0; i
< FTRACE_FUNC_HASHSIZE
; i
++) {
2926 struct hlist_head
*hhd
= &ftrace_func_hash
[i
];
2930 /* Nothing registered? */
2931 if (i
== FTRACE_FUNC_HASHSIZE
)
2934 ret
= __register_ftrace_function(&trace_probe_ops
);
2936 ret
= ftrace_startup(&trace_probe_ops
, 0);
2938 ftrace_probe_registered
= 1;
2941 static void __disable_ftrace_function_probe(void)
2946 if (!ftrace_probe_registered
)
2949 for (i
= 0; i
< FTRACE_FUNC_HASHSIZE
; i
++) {
2950 struct hlist_head
*hhd
= &ftrace_func_hash
[i
];
2955 /* no more funcs left */
2956 ret
= __unregister_ftrace_function(&trace_probe_ops
);
2958 ftrace_shutdown(&trace_probe_ops
, 0);
2960 ftrace_probe_registered
= 0;
2964 static void ftrace_free_entry(struct ftrace_func_probe
*entry
)
2966 if (entry
->ops
->free
)
2967 entry
->ops
->free(entry
->ops
, entry
->ip
, &entry
->data
);
2972 register_ftrace_function_probe(char *glob
, struct ftrace_probe_ops
*ops
,
2975 struct ftrace_func_probe
*entry
;
2976 struct ftrace_hash
**orig_hash
= &trace_probe_ops
.filter_hash
;
2977 struct ftrace_hash
*hash
;
2978 struct ftrace_page
*pg
;
2979 struct dyn_ftrace
*rec
;
2986 type
= filter_parse_regex(glob
, strlen(glob
), &search
, ¬);
2987 len
= strlen(search
);
2989 /* we do not support '!' for function probes */
2993 mutex_lock(&ftrace_lock
);
2995 hash
= alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
, *orig_hash
);
3001 if (unlikely(ftrace_disabled
)) {
3006 do_for_each_ftrace_rec(pg
, rec
) {
3008 if (!ftrace_match_record(rec
, NULL
, search
, len
, type
))
3011 entry
= kmalloc(sizeof(*entry
), GFP_KERNEL
);
3013 /* If we did not process any, then return error */
3024 * The caller might want to do something special
3025 * for each function we find. We call the callback
3026 * to give the caller an opportunity to do so.
3029 if (ops
->init(ops
, rec
->ip
, &entry
->data
) < 0) {
3030 /* caller does not like this func */
3036 ret
= enter_record(hash
, rec
, 0);
3044 entry
->ip
= rec
->ip
;
3046 key
= hash_long(entry
->ip
, FTRACE_HASH_BITS
);
3047 hlist_add_head_rcu(&entry
->node
, &ftrace_func_hash
[key
]);
3049 } while_for_each_ftrace_rec();
3051 ret
= ftrace_hash_move(&trace_probe_ops
, 1, orig_hash
, hash
);
3055 __enable_ftrace_function_probe();
3058 mutex_unlock(&ftrace_lock
);
3059 free_ftrace_hash(hash
);
3065 PROBE_TEST_FUNC
= 1,
3070 __unregister_ftrace_function_probe(char *glob
, struct ftrace_probe_ops
*ops
,
3071 void *data
, int flags
)
3073 struct ftrace_func_entry
*rec_entry
;
3074 struct ftrace_func_probe
*entry
;
3075 struct ftrace_func_probe
*p
;
3076 struct ftrace_hash
**orig_hash
= &trace_probe_ops
.filter_hash
;
3077 struct list_head free_list
;
3078 struct ftrace_hash
*hash
;
3079 struct hlist_node
*tmp
;
3080 char str
[KSYM_SYMBOL_LEN
];
3081 int type
= MATCH_FULL
;
3085 if (glob
&& (strcmp(glob
, "*") == 0 || !strlen(glob
)))
3090 type
= filter_parse_regex(glob
, strlen(glob
), &search
, ¬);
3091 len
= strlen(search
);
3093 /* we do not support '!' for function probes */
3098 mutex_lock(&ftrace_lock
);
3100 hash
= alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
, *orig_hash
);
3102 /* Hmm, should report this somehow */
3105 INIT_LIST_HEAD(&free_list
);
3107 for (i
= 0; i
< FTRACE_FUNC_HASHSIZE
; i
++) {
3108 struct hlist_head
*hhd
= &ftrace_func_hash
[i
];
3110 hlist_for_each_entry_safe(entry
, tmp
, hhd
, node
) {
3112 /* break up if statements for readability */
3113 if ((flags
& PROBE_TEST_FUNC
) && entry
->ops
!= ops
)
3116 if ((flags
& PROBE_TEST_DATA
) && entry
->data
!= data
)
3119 /* do this last, since it is the most expensive */
3121 kallsyms_lookup(entry
->ip
, NULL
, NULL
,
3123 if (!ftrace_match(str
, glob
, len
, type
))
3127 rec_entry
= ftrace_lookup_ip(hash
, entry
->ip
);
3128 /* It is possible more than one entry had this ip */
3130 free_hash_entry(hash
, rec_entry
);
3132 hlist_del_rcu(&entry
->node
);
3133 list_add(&entry
->free_list
, &free_list
);
3136 __disable_ftrace_function_probe();
3138 * Remove after the disable is called. Otherwise, if the last
3139 * probe is removed, a null hash means *all enabled*.
3141 ftrace_hash_move(&trace_probe_ops
, 1, orig_hash
, hash
);
3142 synchronize_sched();
3143 list_for_each_entry_safe(entry
, p
, &free_list
, free_list
) {
3144 list_del(&entry
->free_list
);
3145 ftrace_free_entry(entry
);
3149 mutex_unlock(&ftrace_lock
);
3150 free_ftrace_hash(hash
);
3154 unregister_ftrace_function_probe(char *glob
, struct ftrace_probe_ops
*ops
,
3157 __unregister_ftrace_function_probe(glob
, ops
, data
,
3158 PROBE_TEST_FUNC
| PROBE_TEST_DATA
);
3162 unregister_ftrace_function_probe_func(char *glob
, struct ftrace_probe_ops
*ops
)
3164 __unregister_ftrace_function_probe(glob
, ops
, NULL
, PROBE_TEST_FUNC
);
3167 void unregister_ftrace_function_probe_all(char *glob
)
3169 __unregister_ftrace_function_probe(glob
, NULL
, NULL
, 0);
3172 static LIST_HEAD(ftrace_commands
);
3173 static DEFINE_MUTEX(ftrace_cmd_mutex
);
3175 int register_ftrace_command(struct ftrace_func_command
*cmd
)
3177 struct ftrace_func_command
*p
;
3180 mutex_lock(&ftrace_cmd_mutex
);
3181 list_for_each_entry(p
, &ftrace_commands
, list
) {
3182 if (strcmp(cmd
->name
, p
->name
) == 0) {
3187 list_add(&cmd
->list
, &ftrace_commands
);
3189 mutex_unlock(&ftrace_cmd_mutex
);
3194 int unregister_ftrace_command(struct ftrace_func_command
*cmd
)
3196 struct ftrace_func_command
*p
, *n
;
3199 mutex_lock(&ftrace_cmd_mutex
);
3200 list_for_each_entry_safe(p
, n
, &ftrace_commands
, list
) {
3201 if (strcmp(cmd
->name
, p
->name
) == 0) {
3203 list_del_init(&p
->list
);
3208 mutex_unlock(&ftrace_cmd_mutex
);
3213 static int ftrace_process_regex(struct ftrace_hash
*hash
,
3214 char *buff
, int len
, int enable
)
3216 char *func
, *command
, *next
= buff
;
3217 struct ftrace_func_command
*p
;
3220 func
= strsep(&next
, ":");
3223 ret
= ftrace_match_records(hash
, func
, len
);
3233 command
= strsep(&next
, ":");
3235 mutex_lock(&ftrace_cmd_mutex
);
3236 list_for_each_entry(p
, &ftrace_commands
, list
) {
3237 if (strcmp(p
->name
, command
) == 0) {
3238 ret
= p
->func(hash
, func
, command
, next
, enable
);
3243 mutex_unlock(&ftrace_cmd_mutex
);
3249 ftrace_regex_write(struct file
*file
, const char __user
*ubuf
,
3250 size_t cnt
, loff_t
*ppos
, int enable
)
3252 struct ftrace_iterator
*iter
;
3253 struct trace_parser
*parser
;
3259 mutex_lock(&ftrace_regex_lock
);
3262 if (unlikely(ftrace_disabled
))
3265 if (file
->f_mode
& FMODE_READ
) {
3266 struct seq_file
*m
= file
->private_data
;
3269 iter
= file
->private_data
;
3271 parser
= &iter
->parser
;
3272 read
= trace_get_user(parser
, ubuf
, cnt
, ppos
);
3274 if (read
>= 0 && trace_parser_loaded(parser
) &&
3275 !trace_parser_cont(parser
)) {
3276 ret
= ftrace_process_regex(iter
->hash
, parser
->buffer
,
3277 parser
->idx
, enable
);
3278 trace_parser_clear(parser
);
3285 mutex_unlock(&ftrace_regex_lock
);
3291 ftrace_filter_write(struct file
*file
, const char __user
*ubuf
,
3292 size_t cnt
, loff_t
*ppos
)
3294 return ftrace_regex_write(file
, ubuf
, cnt
, ppos
, 1);
3298 ftrace_notrace_write(struct file
*file
, const char __user
*ubuf
,
3299 size_t cnt
, loff_t
*ppos
)
3301 return ftrace_regex_write(file
, ubuf
, cnt
, ppos
, 0);
3305 ftrace_match_addr(struct ftrace_hash
*hash
, unsigned long ip
, int remove
)
3307 struct ftrace_func_entry
*entry
;
3309 if (!ftrace_location(ip
))
3313 entry
= ftrace_lookup_ip(hash
, ip
);
3316 free_hash_entry(hash
, entry
);
3320 return add_hash_entry(hash
, ip
);
3324 ftrace_set_hash(struct ftrace_ops
*ops
, unsigned char *buf
, int len
,
3325 unsigned long ip
, int remove
, int reset
, int enable
)
3327 struct ftrace_hash
**orig_hash
;
3328 struct ftrace_hash
*hash
;
3331 /* All global ops uses the global ops filters */
3332 if (ops
->flags
& FTRACE_OPS_FL_GLOBAL
)
3335 if (unlikely(ftrace_disabled
))
3339 orig_hash
= &ops
->filter_hash
;
3341 orig_hash
= &ops
->notrace_hash
;
3343 hash
= alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
, *orig_hash
);
3347 mutex_lock(&ftrace_regex_lock
);
3349 ftrace_filter_reset(hash
);
3350 if (buf
&& !ftrace_match_records(hash
, buf
, len
)) {
3352 goto out_regex_unlock
;
3355 ret
= ftrace_match_addr(hash
, ip
, remove
);
3357 goto out_regex_unlock
;
3360 mutex_lock(&ftrace_lock
);
3361 ret
= ftrace_hash_move(ops
, enable
, orig_hash
, hash
);
3362 if (!ret
&& ops
->flags
& FTRACE_OPS_FL_ENABLED
3364 ftrace_run_update_code(FTRACE_UPDATE_CALLS
);
3366 mutex_unlock(&ftrace_lock
);
3369 mutex_unlock(&ftrace_regex_lock
);
3371 free_ftrace_hash(hash
);
3376 ftrace_set_addr(struct ftrace_ops
*ops
, unsigned long ip
, int remove
,
3377 int reset
, int enable
)
3379 return ftrace_set_hash(ops
, 0, 0, ip
, remove
, reset
, enable
);
3383 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
3384 * @ops - the ops to set the filter with
3385 * @ip - the address to add to or remove from the filter.
3386 * @remove - non zero to remove the ip from the filter
3387 * @reset - non zero to reset all filters before applying this filter.
3389 * Filters denote which functions should be enabled when tracing is enabled
3390 * If @ip is NULL, it failes to update filter.
3392 int ftrace_set_filter_ip(struct ftrace_ops
*ops
, unsigned long ip
,
3393 int remove
, int reset
)
3395 return ftrace_set_addr(ops
, ip
, remove
, reset
, 1);
3397 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip
);
3400 ftrace_set_regex(struct ftrace_ops
*ops
, unsigned char *buf
, int len
,
3401 int reset
, int enable
)
3403 return ftrace_set_hash(ops
, buf
, len
, 0, 0, reset
, enable
);
3407 * ftrace_set_filter - set a function to filter on in ftrace
3408 * @ops - the ops to set the filter with
3409 * @buf - the string that holds the function filter text.
3410 * @len - the length of the string.
3411 * @reset - non zero to reset all filters before applying this filter.
3413 * Filters denote which functions should be enabled when tracing is enabled.
3414 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3416 int ftrace_set_filter(struct ftrace_ops
*ops
, unsigned char *buf
,
3419 return ftrace_set_regex(ops
, buf
, len
, reset
, 1);
3421 EXPORT_SYMBOL_GPL(ftrace_set_filter
);
3424 * ftrace_set_notrace - set a function to not trace in ftrace
3425 * @ops - the ops to set the notrace filter with
3426 * @buf - the string that holds the function notrace text.
3427 * @len - the length of the string.
3428 * @reset - non zero to reset all filters before applying this filter.
3430 * Notrace Filters denote which functions should not be enabled when tracing
3431 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3434 int ftrace_set_notrace(struct ftrace_ops
*ops
, unsigned char *buf
,
3437 return ftrace_set_regex(ops
, buf
, len
, reset
, 0);
3439 EXPORT_SYMBOL_GPL(ftrace_set_notrace
);
3441 * ftrace_set_filter - set a function to filter on in ftrace
3442 * @ops - the ops to set the filter with
3443 * @buf - the string that holds the function filter text.
3444 * @len - the length of the string.
3445 * @reset - non zero to reset all filters before applying this filter.
3447 * Filters denote which functions should be enabled when tracing is enabled.
3448 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3450 void ftrace_set_global_filter(unsigned char *buf
, int len
, int reset
)
3452 ftrace_set_regex(&global_ops
, buf
, len
, reset
, 1);
3454 EXPORT_SYMBOL_GPL(ftrace_set_global_filter
);
3457 * ftrace_set_notrace - set a function to not trace in ftrace
3458 * @ops - the ops to set the notrace filter with
3459 * @buf - the string that holds the function notrace text.
3460 * @len - the length of the string.
3461 * @reset - non zero to reset all filters before applying this filter.
3463 * Notrace Filters denote which functions should not be enabled when tracing
3464 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3467 void ftrace_set_global_notrace(unsigned char *buf
, int len
, int reset
)
3469 ftrace_set_regex(&global_ops
, buf
, len
, reset
, 0);
3471 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace
);
3474 * command line interface to allow users to set filters on boot up.
3476 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
3477 static char ftrace_notrace_buf
[FTRACE_FILTER_SIZE
] __initdata
;
3478 static char ftrace_filter_buf
[FTRACE_FILTER_SIZE
] __initdata
;
3480 static int __init
set_ftrace_notrace(char *str
)
3482 strlcpy(ftrace_notrace_buf
, str
, FTRACE_FILTER_SIZE
);
3485 __setup("ftrace_notrace=", set_ftrace_notrace
);
3487 static int __init
set_ftrace_filter(char *str
)
3489 strlcpy(ftrace_filter_buf
, str
, FTRACE_FILTER_SIZE
);
3492 __setup("ftrace_filter=", set_ftrace_filter
);
3494 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3495 static char ftrace_graph_buf
[FTRACE_FILTER_SIZE
] __initdata
;
3496 static int ftrace_set_func(unsigned long *array
, int *idx
, char *buffer
);
3498 static int __init
set_graph_function(char *str
)
3500 strlcpy(ftrace_graph_buf
, str
, FTRACE_FILTER_SIZE
);
3503 __setup("ftrace_graph_filter=", set_graph_function
);
3505 static void __init
set_ftrace_early_graph(char *buf
)
3511 func
= strsep(&buf
, ",");
3512 /* we allow only one expression at a time */
3513 ret
= ftrace_set_func(ftrace_graph_funcs
, &ftrace_graph_count
,
3516 printk(KERN_DEBUG
"ftrace: function %s not "
3517 "traceable\n", func
);
3520 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3523 ftrace_set_early_filter(struct ftrace_ops
*ops
, char *buf
, int enable
)
3528 func
= strsep(&buf
, ",");
3529 ftrace_set_regex(ops
, func
, strlen(func
), 0, enable
);
3533 static void __init
set_ftrace_early_filters(void)
3535 if (ftrace_filter_buf
[0])
3536 ftrace_set_early_filter(&global_ops
, ftrace_filter_buf
, 1);
3537 if (ftrace_notrace_buf
[0])
3538 ftrace_set_early_filter(&global_ops
, ftrace_notrace_buf
, 0);
3539 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3540 if (ftrace_graph_buf
[0])
3541 set_ftrace_early_graph(ftrace_graph_buf
);
3542 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3545 int ftrace_regex_release(struct inode
*inode
, struct file
*file
)
3547 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
3548 struct ftrace_iterator
*iter
;
3549 struct ftrace_hash
**orig_hash
;
3550 struct trace_parser
*parser
;
3554 mutex_lock(&ftrace_regex_lock
);
3555 if (file
->f_mode
& FMODE_READ
) {
3558 seq_release(inode
, file
);
3560 iter
= file
->private_data
;
3562 parser
= &iter
->parser
;
3563 if (trace_parser_loaded(parser
)) {
3564 parser
->buffer
[parser
->idx
] = 0;
3565 ftrace_match_records(iter
->hash
, parser
->buffer
, parser
->idx
);
3568 trace_parser_put(parser
);
3570 if (file
->f_mode
& FMODE_WRITE
) {
3571 filter_hash
= !!(iter
->flags
& FTRACE_ITER_FILTER
);
3574 orig_hash
= &iter
->ops
->filter_hash
;
3576 orig_hash
= &iter
->ops
->notrace_hash
;
3578 mutex_lock(&ftrace_lock
);
3579 ret
= ftrace_hash_move(iter
->ops
, filter_hash
,
3580 orig_hash
, iter
->hash
);
3581 if (!ret
&& (iter
->ops
->flags
& FTRACE_OPS_FL_ENABLED
)
3583 ftrace_run_update_code(FTRACE_UPDATE_CALLS
);
3585 mutex_unlock(&ftrace_lock
);
3587 free_ftrace_hash(iter
->hash
);
3590 mutex_unlock(&ftrace_regex_lock
);
3594 static const struct file_operations ftrace_avail_fops
= {
3595 .open
= ftrace_avail_open
,
3597 .llseek
= seq_lseek
,
3598 .release
= seq_release_private
,
3601 static const struct file_operations ftrace_enabled_fops
= {
3602 .open
= ftrace_enabled_open
,
3604 .llseek
= seq_lseek
,
3605 .release
= seq_release_private
,
3608 static const struct file_operations ftrace_filter_fops
= {
3609 .open
= ftrace_filter_open
,
3611 .write
= ftrace_filter_write
,
3612 .llseek
= ftrace_filter_lseek
,
3613 .release
= ftrace_regex_release
,
3616 static const struct file_operations ftrace_notrace_fops
= {
3617 .open
= ftrace_notrace_open
,
3619 .write
= ftrace_notrace_write
,
3620 .llseek
= ftrace_filter_lseek
,
3621 .release
= ftrace_regex_release
,
3624 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3626 static DEFINE_MUTEX(graph_lock
);
3628 int ftrace_graph_count
;
3629 int ftrace_graph_filter_enabled
;
3630 unsigned long ftrace_graph_funcs
[FTRACE_GRAPH_MAX_FUNCS
] __read_mostly
;
3633 __g_next(struct seq_file
*m
, loff_t
*pos
)
3635 if (*pos
>= ftrace_graph_count
)
3637 return &ftrace_graph_funcs
[*pos
];
3641 g_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
3644 return __g_next(m
, pos
);
3647 static void *g_start(struct seq_file
*m
, loff_t
*pos
)
3649 mutex_lock(&graph_lock
);
3651 /* Nothing, tell g_show to print all functions are enabled */
3652 if (!ftrace_graph_filter_enabled
&& !*pos
)
3655 return __g_next(m
, pos
);
3658 static void g_stop(struct seq_file
*m
, void *p
)
3660 mutex_unlock(&graph_lock
);
3663 static int g_show(struct seq_file
*m
, void *v
)
3665 unsigned long *ptr
= v
;
3670 if (ptr
== (unsigned long *)1) {
3671 seq_printf(m
, "#### all functions enabled ####\n");
3675 seq_printf(m
, "%ps\n", (void *)*ptr
);
3680 static const struct seq_operations ftrace_graph_seq_ops
= {
3688 ftrace_graph_open(struct inode
*inode
, struct file
*file
)
3692 if (unlikely(ftrace_disabled
))
3695 mutex_lock(&graph_lock
);
3696 if ((file
->f_mode
& FMODE_WRITE
) &&
3697 (file
->f_flags
& O_TRUNC
)) {
3698 ftrace_graph_filter_enabled
= 0;
3699 ftrace_graph_count
= 0;
3700 memset(ftrace_graph_funcs
, 0, sizeof(ftrace_graph_funcs
));
3702 mutex_unlock(&graph_lock
);
3704 if (file
->f_mode
& FMODE_READ
)
3705 ret
= seq_open(file
, &ftrace_graph_seq_ops
);
3711 ftrace_graph_release(struct inode
*inode
, struct file
*file
)
3713 if (file
->f_mode
& FMODE_READ
)
3714 seq_release(inode
, file
);
3719 ftrace_set_func(unsigned long *array
, int *idx
, char *buffer
)
3721 struct dyn_ftrace
*rec
;
3722 struct ftrace_page
*pg
;
3731 type
= filter_parse_regex(buffer
, strlen(buffer
), &search
, ¬);
3732 if (!not && *idx
>= FTRACE_GRAPH_MAX_FUNCS
)
3735 search_len
= strlen(search
);
3737 mutex_lock(&ftrace_lock
);
3739 if (unlikely(ftrace_disabled
)) {
3740 mutex_unlock(&ftrace_lock
);
3744 do_for_each_ftrace_rec(pg
, rec
) {
3746 if (ftrace_match_record(rec
, NULL
, search
, search_len
, type
)) {
3747 /* if it is in the array */
3749 for (i
= 0; i
< *idx
; i
++) {
3750 if (array
[i
] == rec
->ip
) {
3759 array
[(*idx
)++] = rec
->ip
;
3760 if (*idx
>= FTRACE_GRAPH_MAX_FUNCS
)
3765 array
[i
] = array
[--(*idx
)];
3771 } while_for_each_ftrace_rec();
3773 mutex_unlock(&ftrace_lock
);
3778 ftrace_graph_filter_enabled
= !!(*idx
);
3784 ftrace_graph_write(struct file
*file
, const char __user
*ubuf
,
3785 size_t cnt
, loff_t
*ppos
)
3787 struct trace_parser parser
;
3793 mutex_lock(&graph_lock
);
3795 if (trace_parser_get_init(&parser
, FTRACE_BUFF_MAX
)) {
3800 read
= trace_get_user(&parser
, ubuf
, cnt
, ppos
);
3802 if (read
>= 0 && trace_parser_loaded((&parser
))) {
3803 parser
.buffer
[parser
.idx
] = 0;
3805 /* we allow only one expression at a time */
3806 ret
= ftrace_set_func(ftrace_graph_funcs
, &ftrace_graph_count
,
3815 trace_parser_put(&parser
);
3817 mutex_unlock(&graph_lock
);
3822 static const struct file_operations ftrace_graph_fops
= {
3823 .open
= ftrace_graph_open
,
3825 .write
= ftrace_graph_write
,
3826 .llseek
= ftrace_filter_lseek
,
3827 .release
= ftrace_graph_release
,
3829 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3831 static __init
int ftrace_init_dyn_debugfs(struct dentry
*d_tracer
)
3834 trace_create_file("available_filter_functions", 0444,
3835 d_tracer
, NULL
, &ftrace_avail_fops
);
3837 trace_create_file("enabled_functions", 0444,
3838 d_tracer
, NULL
, &ftrace_enabled_fops
);
3840 trace_create_file("set_ftrace_filter", 0644, d_tracer
,
3841 NULL
, &ftrace_filter_fops
);
3843 trace_create_file("set_ftrace_notrace", 0644, d_tracer
,
3844 NULL
, &ftrace_notrace_fops
);
3846 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3847 trace_create_file("set_graph_function", 0444, d_tracer
,
3849 &ftrace_graph_fops
);
3850 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3855 static int ftrace_cmp_ips(const void *a
, const void *b
)
3857 const unsigned long *ipa
= a
;
3858 const unsigned long *ipb
= b
;
3867 static void ftrace_swap_ips(void *a
, void *b
, int size
)
3869 unsigned long *ipa
= a
;
3870 unsigned long *ipb
= b
;
3878 static int ftrace_process_locs(struct module
*mod
,
3879 unsigned long *start
,
3882 struct ftrace_page
*start_pg
;
3883 struct ftrace_page
*pg
;
3884 struct dyn_ftrace
*rec
;
3885 unsigned long count
;
3888 unsigned long flags
= 0; /* Shut up gcc */
3891 count
= end
- start
;
3896 sort(start
, count
, sizeof(*start
),
3897 ftrace_cmp_ips
, ftrace_swap_ips
);
3899 start_pg
= ftrace_allocate_pages(count
);
3903 mutex_lock(&ftrace_lock
);
3906 * Core and each module needs their own pages, as
3907 * modules will free them when they are removed.
3908 * Force a new page to be allocated for modules.
3911 WARN_ON(ftrace_pages
|| ftrace_pages_start
);
3912 /* First initialization */
3913 ftrace_pages
= ftrace_pages_start
= start_pg
;
3918 if (WARN_ON(ftrace_pages
->next
)) {
3919 /* Hmm, we have free pages? */
3920 while (ftrace_pages
->next
)
3921 ftrace_pages
= ftrace_pages
->next
;
3924 ftrace_pages
->next
= start_pg
;
3930 addr
= ftrace_call_adjust(*p
++);
3932 * Some architecture linkers will pad between
3933 * the different mcount_loc sections of different
3934 * object files to satisfy alignments.
3935 * Skip any NULL pointers.
3940 if (pg
->index
== pg
->size
) {
3941 /* We should have allocated enough */
3942 if (WARN_ON(!pg
->next
))
3947 rec
= &pg
->records
[pg
->index
++];
3951 /* We should have used all pages */
3954 /* Assign the last page to ftrace_pages */
3957 /* These new locations need to be initialized */
3958 ftrace_new_pgs
= start_pg
;
3961 * We only need to disable interrupts on start up
3962 * because we are modifying code that an interrupt
3963 * may execute, and the modification is not atomic.
3964 * But for modules, nothing runs the code we modify
3965 * until we are finished with it, and there's no
3966 * reason to cause large interrupt latencies while we do it.
3969 local_irq_save(flags
);
3970 ftrace_update_code(mod
);
3972 local_irq_restore(flags
);
3975 mutex_unlock(&ftrace_lock
);
3980 #ifdef CONFIG_MODULES
3982 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
3984 void ftrace_release_mod(struct module
*mod
)
3986 struct dyn_ftrace
*rec
;
3987 struct ftrace_page
**last_pg
;
3988 struct ftrace_page
*pg
;
3991 mutex_lock(&ftrace_lock
);
3993 if (ftrace_disabled
)
3997 * Each module has its own ftrace_pages, remove
3998 * them from the list.
4000 last_pg
= &ftrace_pages_start
;
4001 for (pg
= ftrace_pages_start
; pg
; pg
= *last_pg
) {
4002 rec
= &pg
->records
[0];
4003 if (within_module_core(rec
->ip
, mod
)) {
4005 * As core pages are first, the first
4006 * page should never be a module page.
4008 if (WARN_ON(pg
== ftrace_pages_start
))
4011 /* Check if we are deleting the last page */
4012 if (pg
== ftrace_pages
)
4013 ftrace_pages
= next_to_ftrace_page(last_pg
);
4015 *last_pg
= pg
->next
;
4016 order
= get_count_order(pg
->size
/ ENTRIES_PER_PAGE
);
4017 free_pages((unsigned long)pg
->records
, order
);
4020 last_pg
= &pg
->next
;
4023 mutex_unlock(&ftrace_lock
);
4026 static void ftrace_init_module(struct module
*mod
,
4027 unsigned long *start
, unsigned long *end
)
4029 if (ftrace_disabled
|| start
== end
)
4031 ftrace_process_locs(mod
, start
, end
);
4034 static int ftrace_module_notify_enter(struct notifier_block
*self
,
4035 unsigned long val
, void *data
)
4037 struct module
*mod
= data
;
4039 if (val
== MODULE_STATE_COMING
)
4040 ftrace_init_module(mod
, mod
->ftrace_callsites
,
4041 mod
->ftrace_callsites
+
4042 mod
->num_ftrace_callsites
);
4046 static int ftrace_module_notify_exit(struct notifier_block
*self
,
4047 unsigned long val
, void *data
)
4049 struct module
*mod
= data
;
4051 if (val
== MODULE_STATE_GOING
)
4052 ftrace_release_mod(mod
);
4057 static int ftrace_module_notify_enter(struct notifier_block
*self
,
4058 unsigned long val
, void *data
)
4062 static int ftrace_module_notify_exit(struct notifier_block
*self
,
4063 unsigned long val
, void *data
)
4067 #endif /* CONFIG_MODULES */
4069 struct notifier_block ftrace_module_enter_nb
= {
4070 .notifier_call
= ftrace_module_notify_enter
,
4071 .priority
= INT_MAX
, /* Run before anything that can use kprobes */
4074 struct notifier_block ftrace_module_exit_nb
= {
4075 .notifier_call
= ftrace_module_notify_exit
,
4076 .priority
= INT_MIN
, /* Run after anything that can remove kprobes */
4079 extern unsigned long __start_mcount_loc
[];
4080 extern unsigned long __stop_mcount_loc
[];
4082 void __init
ftrace_init(void)
4084 unsigned long count
, addr
, flags
;
4087 /* Keep the ftrace pointer to the stub */
4088 addr
= (unsigned long)ftrace_stub
;
4090 local_irq_save(flags
);
4091 ftrace_dyn_arch_init(&addr
);
4092 local_irq_restore(flags
);
4094 /* ftrace_dyn_arch_init places the return code in addr */
4098 count
= __stop_mcount_loc
- __start_mcount_loc
;
4100 ret
= ftrace_dyn_table_alloc(count
);
4104 last_ftrace_enabled
= ftrace_enabled
= 1;
4106 ret
= ftrace_process_locs(NULL
,
4110 ret
= register_module_notifier(&ftrace_module_enter_nb
);
4112 pr_warning("Failed to register trace ftrace module enter notifier\n");
4114 ret
= register_module_notifier(&ftrace_module_exit_nb
);
4116 pr_warning("Failed to register trace ftrace module exit notifier\n");
4118 set_ftrace_early_filters();
4122 ftrace_disabled
= 1;
4127 static struct ftrace_ops global_ops
= {
4128 .func
= ftrace_stub
,
4129 .flags
= FTRACE_OPS_FL_RECURSION_SAFE
,
4132 static int __init
ftrace_nodyn_init(void)
4137 core_initcall(ftrace_nodyn_init
);
4139 static inline int ftrace_init_dyn_debugfs(struct dentry
*d_tracer
) { return 0; }
4140 static inline void ftrace_startup_enable(int command
) { }
4141 /* Keep as macros so we do not need to define the commands */
4142 # define ftrace_startup(ops, command) \
4144 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
4147 # define ftrace_shutdown(ops, command) do { } while (0)
4148 # define ftrace_startup_sysctl() do { } while (0)
4149 # define ftrace_shutdown_sysctl() do { } while (0)
4152 ftrace_ops_test(struct ftrace_ops
*ops
, unsigned long ip
)
4157 #endif /* CONFIG_DYNAMIC_FTRACE */
4160 ftrace_ops_control_func(unsigned long ip
, unsigned long parent_ip
,
4161 struct ftrace_ops
*op
, struct pt_regs
*regs
)
4163 if (unlikely(trace_recursion_test(TRACE_CONTROL_BIT
)))
4167 * Some of the ops may be dynamically allocated,
4168 * they must be freed after a synchronize_sched().
4170 preempt_disable_notrace();
4171 trace_recursion_set(TRACE_CONTROL_BIT
);
4172 do_for_each_ftrace_op(op
, ftrace_control_list
) {
4173 if (!(op
->flags
& FTRACE_OPS_FL_STUB
) &&
4174 !ftrace_function_local_disabled(op
) &&
4175 ftrace_ops_test(op
, ip
))
4176 op
->func(ip
, parent_ip
, op
, regs
);
4177 } while_for_each_ftrace_op(op
);
4178 trace_recursion_clear(TRACE_CONTROL_BIT
);
4179 preempt_enable_notrace();
4182 static struct ftrace_ops control_ops
= {
4183 .func
= ftrace_ops_control_func
,
4184 .flags
= FTRACE_OPS_FL_RECURSION_SAFE
,
4188 __ftrace_ops_list_func(unsigned long ip
, unsigned long parent_ip
,
4189 struct ftrace_ops
*ignored
, struct pt_regs
*regs
)
4191 struct ftrace_ops
*op
;
4194 if (function_trace_stop
)
4197 bit
= trace_test_and_set_recursion(TRACE_LIST_START
, TRACE_LIST_MAX
);
4202 * Some of the ops may be dynamically allocated,
4203 * they must be freed after a synchronize_sched().
4205 preempt_disable_notrace();
4206 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
4207 if (ftrace_ops_test(op
, ip
))
4208 op
->func(ip
, parent_ip
, op
, regs
);
4209 } while_for_each_ftrace_op(op
);
4210 preempt_enable_notrace();
4211 trace_clear_recursion(bit
);
4215 * Some archs only support passing ip and parent_ip. Even though
4216 * the list function ignores the op parameter, we do not want any
4217 * C side effects, where a function is called without the caller
4218 * sending a third parameter.
4219 * Archs are to support both the regs and ftrace_ops at the same time.
4220 * If they support ftrace_ops, it is assumed they support regs.
4221 * If call backs want to use regs, they must either check for regs
4222 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
4223 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
4224 * An architecture can pass partial regs with ftrace_ops and still
4225 * set the ARCH_SUPPORT_FTARCE_OPS.
4227 #if ARCH_SUPPORTS_FTRACE_OPS
4228 static void ftrace_ops_list_func(unsigned long ip
, unsigned long parent_ip
,
4229 struct ftrace_ops
*op
, struct pt_regs
*regs
)
4231 __ftrace_ops_list_func(ip
, parent_ip
, NULL
, regs
);
4234 static void ftrace_ops_no_ops(unsigned long ip
, unsigned long parent_ip
)
4236 __ftrace_ops_list_func(ip
, parent_ip
, NULL
, NULL
);
4240 static void clear_ftrace_swapper(void)
4242 struct task_struct
*p
;
4246 for_each_online_cpu(cpu
) {
4248 clear_tsk_trace_trace(p
);
4253 static void set_ftrace_swapper(void)
4255 struct task_struct
*p
;
4259 for_each_online_cpu(cpu
) {
4261 set_tsk_trace_trace(p
);
4266 static void clear_ftrace_pid(struct pid
*pid
)
4268 struct task_struct
*p
;
4271 do_each_pid_task(pid
, PIDTYPE_PID
, p
) {
4272 clear_tsk_trace_trace(p
);
4273 } while_each_pid_task(pid
, PIDTYPE_PID
, p
);
4279 static void set_ftrace_pid(struct pid
*pid
)
4281 struct task_struct
*p
;
4284 do_each_pid_task(pid
, PIDTYPE_PID
, p
) {
4285 set_tsk_trace_trace(p
);
4286 } while_each_pid_task(pid
, PIDTYPE_PID
, p
);
4290 static void clear_ftrace_pid_task(struct pid
*pid
)
4292 if (pid
== ftrace_swapper_pid
)
4293 clear_ftrace_swapper();
4295 clear_ftrace_pid(pid
);
4298 static void set_ftrace_pid_task(struct pid
*pid
)
4300 if (pid
== ftrace_swapper_pid
)
4301 set_ftrace_swapper();
4303 set_ftrace_pid(pid
);
4306 static int ftrace_pid_add(int p
)
4309 struct ftrace_pid
*fpid
;
4312 mutex_lock(&ftrace_lock
);
4315 pid
= ftrace_swapper_pid
;
4317 pid
= find_get_pid(p
);
4324 list_for_each_entry(fpid
, &ftrace_pids
, list
)
4325 if (fpid
->pid
== pid
)
4330 fpid
= kmalloc(sizeof(*fpid
), GFP_KERNEL
);
4334 list_add(&fpid
->list
, &ftrace_pids
);
4337 set_ftrace_pid_task(pid
);
4339 ftrace_update_pid_func();
4340 ftrace_startup_enable(0);
4342 mutex_unlock(&ftrace_lock
);
4346 if (pid
!= ftrace_swapper_pid
)
4350 mutex_unlock(&ftrace_lock
);
4354 static void ftrace_pid_reset(void)
4356 struct ftrace_pid
*fpid
, *safe
;
4358 mutex_lock(&ftrace_lock
);
4359 list_for_each_entry_safe(fpid
, safe
, &ftrace_pids
, list
) {
4360 struct pid
*pid
= fpid
->pid
;
4362 clear_ftrace_pid_task(pid
);
4364 list_del(&fpid
->list
);
4368 ftrace_update_pid_func();
4369 ftrace_startup_enable(0);
4371 mutex_unlock(&ftrace_lock
);
4374 static void *fpid_start(struct seq_file
*m
, loff_t
*pos
)
4376 mutex_lock(&ftrace_lock
);
4378 if (list_empty(&ftrace_pids
) && (!*pos
))
4381 return seq_list_start(&ftrace_pids
, *pos
);
4384 static void *fpid_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
4389 return seq_list_next(v
, &ftrace_pids
, pos
);
4392 static void fpid_stop(struct seq_file
*m
, void *p
)
4394 mutex_unlock(&ftrace_lock
);
4397 static int fpid_show(struct seq_file
*m
, void *v
)
4399 const struct ftrace_pid
*fpid
= list_entry(v
, struct ftrace_pid
, list
);
4401 if (v
== (void *)1) {
4402 seq_printf(m
, "no pid\n");
4406 if (fpid
->pid
== ftrace_swapper_pid
)
4407 seq_printf(m
, "swapper tasks\n");
4409 seq_printf(m
, "%u\n", pid_vnr(fpid
->pid
));
4414 static const struct seq_operations ftrace_pid_sops
= {
4415 .start
= fpid_start
,
4422 ftrace_pid_open(struct inode
*inode
, struct file
*file
)
4426 if ((file
->f_mode
& FMODE_WRITE
) &&
4427 (file
->f_flags
& O_TRUNC
))
4430 if (file
->f_mode
& FMODE_READ
)
4431 ret
= seq_open(file
, &ftrace_pid_sops
);
4437 ftrace_pid_write(struct file
*filp
, const char __user
*ubuf
,
4438 size_t cnt
, loff_t
*ppos
)
4444 if (cnt
>= sizeof(buf
))
4447 if (copy_from_user(&buf
, ubuf
, cnt
))
4453 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
4454 * to clean the filter quietly.
4456 tmp
= strstrip(buf
);
4457 if (strlen(tmp
) == 0)
4460 ret
= kstrtol(tmp
, 10, &val
);
4464 ret
= ftrace_pid_add(val
);
4466 return ret
? ret
: cnt
;
4470 ftrace_pid_release(struct inode
*inode
, struct file
*file
)
4472 if (file
->f_mode
& FMODE_READ
)
4473 seq_release(inode
, file
);
4478 static const struct file_operations ftrace_pid_fops
= {
4479 .open
= ftrace_pid_open
,
4480 .write
= ftrace_pid_write
,
4482 .llseek
= ftrace_filter_lseek
,
4483 .release
= ftrace_pid_release
,
4486 static __init
int ftrace_init_debugfs(void)
4488 struct dentry
*d_tracer
;
4490 d_tracer
= tracing_init_dentry();
4494 ftrace_init_dyn_debugfs(d_tracer
);
4496 trace_create_file("set_ftrace_pid", 0644, d_tracer
,
4497 NULL
, &ftrace_pid_fops
);
4499 ftrace_profile_debugfs(d_tracer
);
4503 fs_initcall(ftrace_init_debugfs
);
4506 * ftrace_kill - kill ftrace
4508 * This function should be used by panic code. It stops ftrace
4509 * but in a not so nice way. If you need to simply kill ftrace
4510 * from a non-atomic section, use ftrace_kill.
4512 void ftrace_kill(void)
4514 ftrace_disabled
= 1;
4516 clear_ftrace_function();
4520 * Test if ftrace is dead or not.
4522 int ftrace_is_dead(void)
4524 return ftrace_disabled
;
4528 * register_ftrace_function - register a function for profiling
4529 * @ops - ops structure that holds the function for profiling.
4531 * Register a function to be called by all functions in the
4534 * Note: @ops->func and all the functions it calls must be labeled
4535 * with "notrace", otherwise it will go into a
4538 int register_ftrace_function(struct ftrace_ops
*ops
)
4542 mutex_lock(&ftrace_lock
);
4544 ret
= __register_ftrace_function(ops
);
4546 ret
= ftrace_startup(ops
, 0);
4548 mutex_unlock(&ftrace_lock
);
4552 EXPORT_SYMBOL_GPL(register_ftrace_function
);
4555 * unregister_ftrace_function - unregister a function for profiling.
4556 * @ops - ops structure that holds the function to unregister
4558 * Unregister a function that was added to be called by ftrace profiling.
4560 int unregister_ftrace_function(struct ftrace_ops
*ops
)
4564 mutex_lock(&ftrace_lock
);
4565 ret
= __unregister_ftrace_function(ops
);
4567 ftrace_shutdown(ops
, 0);
4568 mutex_unlock(&ftrace_lock
);
4572 EXPORT_SYMBOL_GPL(unregister_ftrace_function
);
4575 ftrace_enable_sysctl(struct ctl_table
*table
, int write
,
4576 void __user
*buffer
, size_t *lenp
,
4581 mutex_lock(&ftrace_lock
);
4583 if (unlikely(ftrace_disabled
))
4586 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
4588 if (ret
|| !write
|| (last_ftrace_enabled
== !!ftrace_enabled
))
4591 last_ftrace_enabled
= !!ftrace_enabled
;
4593 if (ftrace_enabled
) {
4595 ftrace_startup_sysctl();
4597 /* we are starting ftrace again */
4598 if (ftrace_ops_list
!= &ftrace_list_end
)
4599 update_ftrace_function();
4602 /* stopping ftrace calls (just send to ftrace_stub) */
4603 ftrace_trace_function
= ftrace_stub
;
4605 ftrace_shutdown_sysctl();
4609 mutex_unlock(&ftrace_lock
);
4613 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4615 static int ftrace_graph_active
;
4616 static struct notifier_block ftrace_suspend_notifier
;
4618 int ftrace_graph_entry_stub(struct ftrace_graph_ent
*trace
)
4623 /* The callbacks that hook a function */
4624 trace_func_graph_ret_t ftrace_graph_return
=
4625 (trace_func_graph_ret_t
)ftrace_stub
;
4626 trace_func_graph_ent_t ftrace_graph_entry
= ftrace_graph_entry_stub
;
4628 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
4629 static int alloc_retstack_tasklist(struct ftrace_ret_stack
**ret_stack_list
)
4633 unsigned long flags
;
4634 int start
= 0, end
= FTRACE_RETSTACK_ALLOC_SIZE
;
4635 struct task_struct
*g
, *t
;
4637 for (i
= 0; i
< FTRACE_RETSTACK_ALLOC_SIZE
; i
++) {
4638 ret_stack_list
[i
] = kmalloc(FTRACE_RETFUNC_DEPTH
4639 * sizeof(struct ftrace_ret_stack
),
4641 if (!ret_stack_list
[i
]) {
4649 read_lock_irqsave(&tasklist_lock
, flags
);
4650 do_each_thread(g
, t
) {
4656 if (t
->ret_stack
== NULL
) {
4657 atomic_set(&t
->tracing_graph_pause
, 0);
4658 atomic_set(&t
->trace_overrun
, 0);
4659 t
->curr_ret_stack
= -1;
4660 /* Make sure the tasks see the -1 first: */
4662 t
->ret_stack
= ret_stack_list
[start
++];
4664 } while_each_thread(g
, t
);
4667 read_unlock_irqrestore(&tasklist_lock
, flags
);
4669 for (i
= start
; i
< end
; i
++)
4670 kfree(ret_stack_list
[i
]);
4675 ftrace_graph_probe_sched_switch(void *ignore
,
4676 struct task_struct
*prev
, struct task_struct
*next
)
4678 unsigned long long timestamp
;
4682 * Does the user want to count the time a function was asleep.
4683 * If so, do not update the time stamps.
4685 if (trace_flags
& TRACE_ITER_SLEEP_TIME
)
4688 timestamp
= trace_clock_local();
4690 prev
->ftrace_timestamp
= timestamp
;
4692 /* only process tasks that we timestamped */
4693 if (!next
->ftrace_timestamp
)
4697 * Update all the counters in next to make up for the
4698 * time next was sleeping.
4700 timestamp
-= next
->ftrace_timestamp
;
4702 for (index
= next
->curr_ret_stack
; index
>= 0; index
--)
4703 next
->ret_stack
[index
].calltime
+= timestamp
;
4706 /* Allocate a return stack for each task */
4707 static int start_graph_tracing(void)
4709 struct ftrace_ret_stack
**ret_stack_list
;
4712 ret_stack_list
= kmalloc(FTRACE_RETSTACK_ALLOC_SIZE
*
4713 sizeof(struct ftrace_ret_stack
*),
4716 if (!ret_stack_list
)
4719 /* The cpu_boot init_task->ret_stack will never be freed */
4720 for_each_online_cpu(cpu
) {
4721 if (!idle_task(cpu
)->ret_stack
)
4722 ftrace_graph_init_idle_task(idle_task(cpu
), cpu
);
4726 ret
= alloc_retstack_tasklist(ret_stack_list
);
4727 } while (ret
== -EAGAIN
);
4730 ret
= register_trace_sched_switch(ftrace_graph_probe_sched_switch
, NULL
);
4732 pr_info("ftrace_graph: Couldn't activate tracepoint"
4733 " probe to kernel_sched_switch\n");
4736 kfree(ret_stack_list
);
4741 * Hibernation protection.
4742 * The state of the current task is too much unstable during
4743 * suspend/restore to disk. We want to protect against that.
4746 ftrace_suspend_notifier_call(struct notifier_block
*bl
, unsigned long state
,
4750 case PM_HIBERNATION_PREPARE
:
4751 pause_graph_tracing();
4754 case PM_POST_HIBERNATION
:
4755 unpause_graph_tracing();
4761 int register_ftrace_graph(trace_func_graph_ret_t retfunc
,
4762 trace_func_graph_ent_t entryfunc
)
4766 mutex_lock(&ftrace_lock
);
4768 /* we currently allow only one tracer registered at a time */
4769 if (ftrace_graph_active
) {
4774 ftrace_suspend_notifier
.notifier_call
= ftrace_suspend_notifier_call
;
4775 register_pm_notifier(&ftrace_suspend_notifier
);
4777 ftrace_graph_active
++;
4778 ret
= start_graph_tracing();
4780 ftrace_graph_active
--;
4784 ftrace_graph_return
= retfunc
;
4785 ftrace_graph_entry
= entryfunc
;
4787 ret
= ftrace_startup(&global_ops
, FTRACE_START_FUNC_RET
);
4790 mutex_unlock(&ftrace_lock
);
4794 void unregister_ftrace_graph(void)
4796 mutex_lock(&ftrace_lock
);
4798 if (unlikely(!ftrace_graph_active
))
4801 ftrace_graph_active
--;
4802 ftrace_graph_return
= (trace_func_graph_ret_t
)ftrace_stub
;
4803 ftrace_graph_entry
= ftrace_graph_entry_stub
;
4804 ftrace_shutdown(&global_ops
, FTRACE_STOP_FUNC_RET
);
4805 unregister_pm_notifier(&ftrace_suspend_notifier
);
4806 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch
, NULL
);
4809 mutex_unlock(&ftrace_lock
);
4812 static DEFINE_PER_CPU(struct ftrace_ret_stack
*, idle_ret_stack
);
4815 graph_init_task(struct task_struct
*t
, struct ftrace_ret_stack
*ret_stack
)
4817 atomic_set(&t
->tracing_graph_pause
, 0);
4818 atomic_set(&t
->trace_overrun
, 0);
4819 t
->ftrace_timestamp
= 0;
4820 /* make curr_ret_stack visible before we add the ret_stack */
4822 t
->ret_stack
= ret_stack
;
4826 * Allocate a return stack for the idle task. May be the first
4827 * time through, or it may be done by CPU hotplug online.
4829 void ftrace_graph_init_idle_task(struct task_struct
*t
, int cpu
)
4831 t
->curr_ret_stack
= -1;
4833 * The idle task has no parent, it either has its own
4834 * stack or no stack at all.
4837 WARN_ON(t
->ret_stack
!= per_cpu(idle_ret_stack
, cpu
));
4839 if (ftrace_graph_active
) {
4840 struct ftrace_ret_stack
*ret_stack
;
4842 ret_stack
= per_cpu(idle_ret_stack
, cpu
);
4844 ret_stack
= kmalloc(FTRACE_RETFUNC_DEPTH
4845 * sizeof(struct ftrace_ret_stack
),
4849 per_cpu(idle_ret_stack
, cpu
) = ret_stack
;
4851 graph_init_task(t
, ret_stack
);
4855 /* Allocate a return stack for newly created task */
4856 void ftrace_graph_init_task(struct task_struct
*t
)
4858 /* Make sure we do not use the parent ret_stack */
4859 t
->ret_stack
= NULL
;
4860 t
->curr_ret_stack
= -1;
4862 if (ftrace_graph_active
) {
4863 struct ftrace_ret_stack
*ret_stack
;
4865 ret_stack
= kmalloc(FTRACE_RETFUNC_DEPTH
4866 * sizeof(struct ftrace_ret_stack
),
4870 graph_init_task(t
, ret_stack
);
4874 void ftrace_graph_exit_task(struct task_struct
*t
)
4876 struct ftrace_ret_stack
*ret_stack
= t
->ret_stack
;
4878 t
->ret_stack
= NULL
;
4879 /* NULL must become visible to IRQs before we free it: */
4885 void ftrace_graph_stop(void)