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/tracefs.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 #ifdef CONFIG_DYNAMIC_FTRACE
66 #define INIT_OPS_HASH(opsname) \
67 .func_hash = &opsname.local_hash, \
68 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
69 #define ASSIGN_OPS_HASH(opsname, val) \
71 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
73 #define INIT_OPS_HASH(opsname)
74 #define ASSIGN_OPS_HASH(opsname, val)
77 static struct ftrace_ops ftrace_list_end __read_mostly
= {
79 .flags
= FTRACE_OPS_FL_RECURSION_SAFE
| FTRACE_OPS_FL_STUB
,
80 INIT_OPS_HASH(ftrace_list_end
)
83 /* ftrace_enabled is a method to turn ftrace on or off */
84 int ftrace_enabled __read_mostly
;
85 static int last_ftrace_enabled
;
87 /* Current function tracing op */
88 struct ftrace_ops
*function_trace_op __read_mostly
= &ftrace_list_end
;
89 /* What to set function_trace_op to */
90 static struct ftrace_ops
*set_function_trace_op
;
92 static bool ftrace_pids_enabled(struct ftrace_ops
*ops
)
94 struct trace_array
*tr
;
96 if (!(ops
->flags
& FTRACE_OPS_FL_PID
) || !ops
->private)
101 return tr
->function_pids
!= NULL
;
104 static void ftrace_update_trampoline(struct ftrace_ops
*ops
);
107 * ftrace_disabled is set when an anomaly is discovered.
108 * ftrace_disabled is much stronger than ftrace_enabled.
110 static int ftrace_disabled __read_mostly
;
112 static DEFINE_MUTEX(ftrace_lock
);
114 static struct ftrace_ops
*ftrace_ops_list __read_mostly
= &ftrace_list_end
;
115 ftrace_func_t ftrace_trace_function __read_mostly
= ftrace_stub
;
116 static struct ftrace_ops global_ops
;
118 #if ARCH_SUPPORTS_FTRACE_OPS
119 static void ftrace_ops_list_func(unsigned long ip
, unsigned long parent_ip
,
120 struct ftrace_ops
*op
, struct pt_regs
*regs
);
122 /* See comment below, where ftrace_ops_list_func is defined */
123 static void ftrace_ops_no_ops(unsigned long ip
, unsigned long parent_ip
);
124 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
128 * Traverse the ftrace_global_list, invoking all entries. The reason that we
129 * can use rcu_dereference_raw_notrace() is that elements removed from this list
130 * are simply leaked, so there is no need to interact with a grace-period
131 * mechanism. The rcu_dereference_raw_notrace() calls are needed to handle
132 * concurrent insertions into the ftrace_global_list.
134 * Silly Alpha and silly pointer-speculation compiler optimizations!
136 #define do_for_each_ftrace_op(op, list) \
137 op = rcu_dereference_raw_notrace(list); \
141 * Optimized for just a single item in the list (as that is the normal case).
143 #define while_for_each_ftrace_op(op) \
144 while (likely(op = rcu_dereference_raw_notrace((op)->next)) && \
145 unlikely((op) != &ftrace_list_end))
147 static inline void ftrace_ops_init(struct ftrace_ops
*ops
)
149 #ifdef CONFIG_DYNAMIC_FTRACE
150 if (!(ops
->flags
& FTRACE_OPS_FL_INITIALIZED
)) {
151 mutex_init(&ops
->local_hash
.regex_lock
);
152 ops
->func_hash
= &ops
->local_hash
;
153 ops
->flags
|= FTRACE_OPS_FL_INITIALIZED
;
159 * ftrace_nr_registered_ops - return number of ops registered
161 * Returns the number of ftrace_ops registered and tracing functions
163 int ftrace_nr_registered_ops(void)
165 struct ftrace_ops
*ops
;
168 mutex_lock(&ftrace_lock
);
170 for (ops
= ftrace_ops_list
;
171 ops
!= &ftrace_list_end
; ops
= ops
->next
)
174 mutex_unlock(&ftrace_lock
);
179 static void ftrace_pid_func(unsigned long ip
, unsigned long parent_ip
,
180 struct ftrace_ops
*op
, struct pt_regs
*regs
)
182 struct trace_array
*tr
= op
->private;
184 if (tr
&& this_cpu_read(tr
->trace_buffer
.data
->ftrace_ignore_pid
))
187 op
->saved_func(ip
, parent_ip
, op
, regs
);
191 * clear_ftrace_function - reset the ftrace function
193 * This NULLs the ftrace function and in essence stops
194 * tracing. There may be lag
196 void clear_ftrace_function(void)
198 ftrace_trace_function
= ftrace_stub
;
201 static void per_cpu_ops_disable_all(struct ftrace_ops
*ops
)
205 for_each_possible_cpu(cpu
)
206 *per_cpu_ptr(ops
->disabled
, cpu
) = 1;
209 static int per_cpu_ops_alloc(struct ftrace_ops
*ops
)
211 int __percpu
*disabled
;
213 if (WARN_ON_ONCE(!(ops
->flags
& FTRACE_OPS_FL_PER_CPU
)))
216 disabled
= alloc_percpu(int);
220 ops
->disabled
= disabled
;
221 per_cpu_ops_disable_all(ops
);
225 static void ftrace_sync(struct work_struct
*work
)
228 * This function is just a stub to implement a hard force
229 * of synchronize_sched(). This requires synchronizing
230 * tasks even in userspace and idle.
232 * Yes, function tracing is rude.
236 static void ftrace_sync_ipi(void *data
)
238 /* Probably not needed, but do it anyway */
242 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
243 static void update_function_graph_func(void);
245 /* Both enabled by default (can be cleared by function_graph tracer flags */
246 static bool fgraph_sleep_time
= true;
247 static bool fgraph_graph_time
= true;
250 static inline void update_function_graph_func(void) { }
254 static ftrace_func_t
ftrace_ops_get_list_func(struct ftrace_ops
*ops
)
257 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
258 * then it needs to call the list anyway.
260 if (ops
->flags
& (FTRACE_OPS_FL_DYNAMIC
| FTRACE_OPS_FL_PER_CPU
|
261 FTRACE_OPS_FL_RCU
) || FTRACE_FORCE_LIST_FUNC
)
262 return ftrace_ops_list_func
;
264 return ftrace_ops_get_func(ops
);
267 static void update_ftrace_function(void)
272 * Prepare the ftrace_ops that the arch callback will use.
273 * If there's only one ftrace_ops registered, the ftrace_ops_list
274 * will point to the ops we want.
276 set_function_trace_op
= ftrace_ops_list
;
278 /* If there's no ftrace_ops registered, just call the stub function */
279 if (ftrace_ops_list
== &ftrace_list_end
) {
283 * If we are at the end of the list and this ops is
284 * recursion safe and not dynamic and the arch supports passing ops,
285 * then have the mcount trampoline call the function directly.
287 } else if (ftrace_ops_list
->next
== &ftrace_list_end
) {
288 func
= ftrace_ops_get_list_func(ftrace_ops_list
);
291 /* Just use the default ftrace_ops */
292 set_function_trace_op
= &ftrace_list_end
;
293 func
= ftrace_ops_list_func
;
296 update_function_graph_func();
298 /* If there's no change, then do nothing more here */
299 if (ftrace_trace_function
== func
)
303 * If we are using the list function, it doesn't care
304 * about the function_trace_ops.
306 if (func
== ftrace_ops_list_func
) {
307 ftrace_trace_function
= func
;
309 * Don't even bother setting function_trace_ops,
310 * it would be racy to do so anyway.
315 #ifndef CONFIG_DYNAMIC_FTRACE
317 * For static tracing, we need to be a bit more careful.
318 * The function change takes affect immediately. Thus,
319 * we need to coorditate the setting of the function_trace_ops
320 * with the setting of the ftrace_trace_function.
322 * Set the function to the list ops, which will call the
323 * function we want, albeit indirectly, but it handles the
324 * ftrace_ops and doesn't depend on function_trace_op.
326 ftrace_trace_function
= ftrace_ops_list_func
;
328 * Make sure all CPUs see this. Yes this is slow, but static
329 * tracing is slow and nasty to have enabled.
331 schedule_on_each_cpu(ftrace_sync
);
332 /* Now all cpus are using the list ops. */
333 function_trace_op
= set_function_trace_op
;
334 /* Make sure the function_trace_op is visible on all CPUs */
336 /* Nasty way to force a rmb on all cpus */
337 smp_call_function(ftrace_sync_ipi
, NULL
, 1);
338 /* OK, we are all set to update the ftrace_trace_function now! */
339 #endif /* !CONFIG_DYNAMIC_FTRACE */
341 ftrace_trace_function
= func
;
344 int using_ftrace_ops_list_func(void)
346 return ftrace_trace_function
== ftrace_ops_list_func
;
349 static void add_ftrace_ops(struct ftrace_ops
**list
, struct ftrace_ops
*ops
)
353 * We are entering ops into the list but another
354 * CPU might be walking that list. We need to make sure
355 * the ops->next pointer is valid before another CPU sees
356 * the ops pointer included into the list.
358 rcu_assign_pointer(*list
, ops
);
361 static int remove_ftrace_ops(struct ftrace_ops
**list
, struct ftrace_ops
*ops
)
363 struct ftrace_ops
**p
;
366 * If we are removing the last function, then simply point
367 * to the ftrace_stub.
369 if (*list
== ops
&& ops
->next
== &ftrace_list_end
) {
370 *list
= &ftrace_list_end
;
374 for (p
= list
; *p
!= &ftrace_list_end
; p
= &(*p
)->next
)
385 static void ftrace_update_trampoline(struct ftrace_ops
*ops
);
387 static int __register_ftrace_function(struct ftrace_ops
*ops
)
389 if (ops
->flags
& FTRACE_OPS_FL_DELETED
)
392 if (WARN_ON(ops
->flags
& FTRACE_OPS_FL_ENABLED
))
395 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
397 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
398 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
399 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
401 if (ops
->flags
& FTRACE_OPS_FL_SAVE_REGS
&&
402 !(ops
->flags
& FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED
))
405 if (ops
->flags
& FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED
)
406 ops
->flags
|= FTRACE_OPS_FL_SAVE_REGS
;
409 if (!core_kernel_data((unsigned long)ops
))
410 ops
->flags
|= FTRACE_OPS_FL_DYNAMIC
;
412 if (ops
->flags
& FTRACE_OPS_FL_PER_CPU
) {
413 if (per_cpu_ops_alloc(ops
))
417 add_ftrace_ops(&ftrace_ops_list
, ops
);
419 /* Always save the function, and reset at unregistering */
420 ops
->saved_func
= ops
->func
;
422 if (ftrace_pids_enabled(ops
))
423 ops
->func
= ftrace_pid_func
;
425 ftrace_update_trampoline(ops
);
428 update_ftrace_function();
433 static int __unregister_ftrace_function(struct ftrace_ops
*ops
)
437 if (WARN_ON(!(ops
->flags
& FTRACE_OPS_FL_ENABLED
)))
440 ret
= remove_ftrace_ops(&ftrace_ops_list
, ops
);
446 update_ftrace_function();
448 ops
->func
= ops
->saved_func
;
453 static void ftrace_update_pid_func(void)
455 struct ftrace_ops
*op
;
457 /* Only do something if we are tracing something */
458 if (ftrace_trace_function
== ftrace_stub
)
461 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
462 if (op
->flags
& FTRACE_OPS_FL_PID
) {
463 op
->func
= ftrace_pids_enabled(op
) ?
464 ftrace_pid_func
: op
->saved_func
;
465 ftrace_update_trampoline(op
);
467 } while_for_each_ftrace_op(op
);
469 update_ftrace_function();
472 #ifdef CONFIG_FUNCTION_PROFILER
473 struct ftrace_profile
{
474 struct hlist_node node
;
476 unsigned long counter
;
477 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
478 unsigned long long time
;
479 unsigned long long time_squared
;
483 struct ftrace_profile_page
{
484 struct ftrace_profile_page
*next
;
486 struct ftrace_profile records
[];
489 struct ftrace_profile_stat
{
491 struct hlist_head
*hash
;
492 struct ftrace_profile_page
*pages
;
493 struct ftrace_profile_page
*start
;
494 struct tracer_stat stat
;
497 #define PROFILE_RECORDS_SIZE \
498 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
500 #define PROFILES_PER_PAGE \
501 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
503 static int ftrace_profile_enabled __read_mostly
;
505 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
506 static DEFINE_MUTEX(ftrace_profile_lock
);
508 static DEFINE_PER_CPU(struct ftrace_profile_stat
, ftrace_profile_stats
);
510 #define FTRACE_PROFILE_HASH_BITS 10
511 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
514 function_stat_next(void *v
, int idx
)
516 struct ftrace_profile
*rec
= v
;
517 struct ftrace_profile_page
*pg
;
519 pg
= (struct ftrace_profile_page
*)((unsigned long)rec
& PAGE_MASK
);
525 if ((void *)rec
>= (void *)&pg
->records
[pg
->index
]) {
529 rec
= &pg
->records
[0];
537 static void *function_stat_start(struct tracer_stat
*trace
)
539 struct ftrace_profile_stat
*stat
=
540 container_of(trace
, struct ftrace_profile_stat
, stat
);
542 if (!stat
|| !stat
->start
)
545 return function_stat_next(&stat
->start
->records
[0], 0);
548 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
549 /* function graph compares on total time */
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
->time
< b
->time
)
557 if (a
->time
> b
->time
)
563 /* not function graph compares against hits */
564 static int function_stat_cmp(void *p1
, void *p2
)
566 struct ftrace_profile
*a
= p1
;
567 struct ftrace_profile
*b
= p2
;
569 if (a
->counter
< b
->counter
)
571 if (a
->counter
> b
->counter
)
578 static int function_stat_headers(struct seq_file
*m
)
580 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
581 seq_puts(m
, " Function "
584 "--- ---- --- ---\n");
586 seq_puts(m
, " Function Hit\n"
592 static int function_stat_show(struct seq_file
*m
, void *v
)
594 struct ftrace_profile
*rec
= v
;
595 char str
[KSYM_SYMBOL_LEN
];
597 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
598 static struct trace_seq s
;
599 unsigned long long avg
;
600 unsigned long long stddev
;
602 mutex_lock(&ftrace_profile_lock
);
604 /* we raced with function_profile_reset() */
605 if (unlikely(rec
->counter
== 0)) {
610 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
612 do_div(avg
, rec
->counter
);
613 if (tracing_thresh
&& (avg
< tracing_thresh
))
617 kallsyms_lookup(rec
->ip
, NULL
, NULL
, NULL
, str
);
618 seq_printf(m
, " %-30.30s %10lu", str
, rec
->counter
);
620 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
623 /* Sample standard deviation (s^2) */
624 if (rec
->counter
<= 1)
628 * Apply Welford's method:
629 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
631 stddev
= rec
->counter
* rec
->time_squared
-
632 rec
->time
* rec
->time
;
635 * Divide only 1000 for ns^2 -> us^2 conversion.
636 * trace_print_graph_duration will divide 1000 again.
638 do_div(stddev
, rec
->counter
* (rec
->counter
- 1) * 1000);
642 trace_print_graph_duration(rec
->time
, &s
);
643 trace_seq_puts(&s
, " ");
644 trace_print_graph_duration(avg
, &s
);
645 trace_seq_puts(&s
, " ");
646 trace_print_graph_duration(stddev
, &s
);
647 trace_print_seq(m
, &s
);
651 mutex_unlock(&ftrace_profile_lock
);
656 static void ftrace_profile_reset(struct ftrace_profile_stat
*stat
)
658 struct ftrace_profile_page
*pg
;
660 pg
= stat
->pages
= stat
->start
;
663 memset(pg
->records
, 0, PROFILE_RECORDS_SIZE
);
668 memset(stat
->hash
, 0,
669 FTRACE_PROFILE_HASH_SIZE
* sizeof(struct hlist_head
));
672 int ftrace_profile_pages_init(struct ftrace_profile_stat
*stat
)
674 struct ftrace_profile_page
*pg
;
679 /* If we already allocated, do nothing */
683 stat
->pages
= (void *)get_zeroed_page(GFP_KERNEL
);
687 #ifdef CONFIG_DYNAMIC_FTRACE
688 functions
= ftrace_update_tot_cnt
;
691 * We do not know the number of functions that exist because
692 * dynamic tracing is what counts them. With past experience
693 * we have around 20K functions. That should be more than enough.
694 * It is highly unlikely we will execute every function in
700 pg
= stat
->start
= stat
->pages
;
702 pages
= DIV_ROUND_UP(functions
, PROFILES_PER_PAGE
);
704 for (i
= 1; i
< pages
; i
++) {
705 pg
->next
= (void *)get_zeroed_page(GFP_KERNEL
);
716 unsigned long tmp
= (unsigned long)pg
;
728 static int ftrace_profile_init_cpu(int cpu
)
730 struct ftrace_profile_stat
*stat
;
733 stat
= &per_cpu(ftrace_profile_stats
, cpu
);
736 /* If the profile is already created, simply reset it */
737 ftrace_profile_reset(stat
);
742 * We are profiling all functions, but usually only a few thousand
743 * functions are hit. We'll make a hash of 1024 items.
745 size
= FTRACE_PROFILE_HASH_SIZE
;
747 stat
->hash
= kzalloc(sizeof(struct hlist_head
) * size
, GFP_KERNEL
);
752 /* Preallocate the function profiling pages */
753 if (ftrace_profile_pages_init(stat
) < 0) {
762 static int ftrace_profile_init(void)
767 for_each_possible_cpu(cpu
) {
768 ret
= ftrace_profile_init_cpu(cpu
);
776 /* interrupts must be disabled */
777 static struct ftrace_profile
*
778 ftrace_find_profiled_func(struct ftrace_profile_stat
*stat
, unsigned long ip
)
780 struct ftrace_profile
*rec
;
781 struct hlist_head
*hhd
;
784 key
= hash_long(ip
, FTRACE_PROFILE_HASH_BITS
);
785 hhd
= &stat
->hash
[key
];
787 if (hlist_empty(hhd
))
790 hlist_for_each_entry_rcu_notrace(rec
, hhd
, node
) {
798 static void ftrace_add_profile(struct ftrace_profile_stat
*stat
,
799 struct ftrace_profile
*rec
)
803 key
= hash_long(rec
->ip
, FTRACE_PROFILE_HASH_BITS
);
804 hlist_add_head_rcu(&rec
->node
, &stat
->hash
[key
]);
808 * The memory is already allocated, this simply finds a new record to use.
810 static struct ftrace_profile
*
811 ftrace_profile_alloc(struct ftrace_profile_stat
*stat
, unsigned long ip
)
813 struct ftrace_profile
*rec
= NULL
;
815 /* prevent recursion (from NMIs) */
816 if (atomic_inc_return(&stat
->disabled
) != 1)
820 * Try to find the function again since an NMI
821 * could have added it
823 rec
= ftrace_find_profiled_func(stat
, ip
);
827 if (stat
->pages
->index
== PROFILES_PER_PAGE
) {
828 if (!stat
->pages
->next
)
830 stat
->pages
= stat
->pages
->next
;
833 rec
= &stat
->pages
->records
[stat
->pages
->index
++];
835 ftrace_add_profile(stat
, rec
);
838 atomic_dec(&stat
->disabled
);
844 function_profile_call(unsigned long ip
, unsigned long parent_ip
,
845 struct ftrace_ops
*ops
, struct pt_regs
*regs
)
847 struct ftrace_profile_stat
*stat
;
848 struct ftrace_profile
*rec
;
851 if (!ftrace_profile_enabled
)
854 local_irq_save(flags
);
856 stat
= this_cpu_ptr(&ftrace_profile_stats
);
857 if (!stat
->hash
|| !ftrace_profile_enabled
)
860 rec
= ftrace_find_profiled_func(stat
, ip
);
862 rec
= ftrace_profile_alloc(stat
, ip
);
869 local_irq_restore(flags
);
872 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
873 static int profile_graph_entry(struct ftrace_graph_ent
*trace
)
875 int index
= trace
->depth
;
877 function_profile_call(trace
->func
, 0, NULL
, NULL
);
879 if (index
>= 0 && index
< FTRACE_RETFUNC_DEPTH
)
880 current
->ret_stack
[index
].subtime
= 0;
885 static void profile_graph_return(struct ftrace_graph_ret
*trace
)
887 struct ftrace_profile_stat
*stat
;
888 unsigned long long calltime
;
889 struct ftrace_profile
*rec
;
892 local_irq_save(flags
);
893 stat
= this_cpu_ptr(&ftrace_profile_stats
);
894 if (!stat
->hash
|| !ftrace_profile_enabled
)
897 /* If the calltime was zero'd ignore it */
898 if (!trace
->calltime
)
901 calltime
= trace
->rettime
- trace
->calltime
;
903 if (!fgraph_graph_time
) {
906 index
= trace
->depth
;
908 /* Append this call time to the parent time to subtract */
910 current
->ret_stack
[index
- 1].subtime
+= calltime
;
912 if (current
->ret_stack
[index
].subtime
< calltime
)
913 calltime
-= current
->ret_stack
[index
].subtime
;
918 rec
= ftrace_find_profiled_func(stat
, trace
->func
);
920 rec
->time
+= calltime
;
921 rec
->time_squared
+= calltime
* calltime
;
925 local_irq_restore(flags
);
928 static int register_ftrace_profiler(void)
930 return register_ftrace_graph(&profile_graph_return
,
931 &profile_graph_entry
);
934 static void unregister_ftrace_profiler(void)
936 unregister_ftrace_graph();
939 static struct ftrace_ops ftrace_profile_ops __read_mostly
= {
940 .func
= function_profile_call
,
941 .flags
= FTRACE_OPS_FL_RECURSION_SAFE
| FTRACE_OPS_FL_INITIALIZED
,
942 INIT_OPS_HASH(ftrace_profile_ops
)
945 static int register_ftrace_profiler(void)
947 return register_ftrace_function(&ftrace_profile_ops
);
950 static void unregister_ftrace_profiler(void)
952 unregister_ftrace_function(&ftrace_profile_ops
);
954 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
957 ftrace_profile_write(struct file
*filp
, const char __user
*ubuf
,
958 size_t cnt
, loff_t
*ppos
)
963 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
969 mutex_lock(&ftrace_profile_lock
);
970 if (ftrace_profile_enabled
^ val
) {
972 ret
= ftrace_profile_init();
978 ret
= register_ftrace_profiler();
983 ftrace_profile_enabled
= 1;
985 ftrace_profile_enabled
= 0;
987 * unregister_ftrace_profiler calls stop_machine
988 * so this acts like an synchronize_sched.
990 unregister_ftrace_profiler();
994 mutex_unlock(&ftrace_profile_lock
);
1002 ftrace_profile_read(struct file
*filp
, char __user
*ubuf
,
1003 size_t cnt
, loff_t
*ppos
)
1005 char buf
[64]; /* big enough to hold a number */
1008 r
= sprintf(buf
, "%u\n", ftrace_profile_enabled
);
1009 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
1012 static const struct file_operations ftrace_profile_fops
= {
1013 .open
= tracing_open_generic
,
1014 .read
= ftrace_profile_read
,
1015 .write
= ftrace_profile_write
,
1016 .llseek
= default_llseek
,
1019 /* used to initialize the real stat files */
1020 static struct tracer_stat function_stats __initdata
= {
1021 .name
= "functions",
1022 .stat_start
= function_stat_start
,
1023 .stat_next
= function_stat_next
,
1024 .stat_cmp
= function_stat_cmp
,
1025 .stat_headers
= function_stat_headers
,
1026 .stat_show
= function_stat_show
1029 static __init
void ftrace_profile_tracefs(struct dentry
*d_tracer
)
1031 struct ftrace_profile_stat
*stat
;
1032 struct dentry
*entry
;
1037 for_each_possible_cpu(cpu
) {
1038 stat
= &per_cpu(ftrace_profile_stats
, cpu
);
1040 name
= kasprintf(GFP_KERNEL
, "function%d", cpu
);
1043 * The files created are permanent, if something happens
1044 * we still do not free memory.
1047 "Could not allocate stat file for cpu %d\n",
1051 stat
->stat
= function_stats
;
1052 stat
->stat
.name
= name
;
1053 ret
= register_stat_tracer(&stat
->stat
);
1056 "Could not register function stat for cpu %d\n",
1063 entry
= tracefs_create_file("function_profile_enabled", 0644,
1064 d_tracer
, NULL
, &ftrace_profile_fops
);
1066 pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
1069 #else /* CONFIG_FUNCTION_PROFILER */
1070 static __init
void ftrace_profile_tracefs(struct dentry
*d_tracer
)
1073 #endif /* CONFIG_FUNCTION_PROFILER */
1075 static struct pid
* const ftrace_swapper_pid
= &init_struct_pid
;
1077 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1078 static int ftrace_graph_active
;
1080 # define ftrace_graph_active 0
1083 #ifdef CONFIG_DYNAMIC_FTRACE
1085 static struct ftrace_ops
*removed_ops
;
1088 * Set when doing a global update, like enabling all recs or disabling them.
1089 * It is not set when just updating a single ftrace_ops.
1091 static bool update_all_ops
;
1093 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1094 # error Dynamic ftrace depends on MCOUNT_RECORD
1097 static struct hlist_head ftrace_func_hash
[FTRACE_FUNC_HASHSIZE
] __read_mostly
;
1099 struct ftrace_func_probe
{
1100 struct hlist_node node
;
1101 struct ftrace_probe_ops
*ops
;
1102 unsigned long flags
;
1105 struct list_head free_list
;
1108 struct ftrace_func_entry
{
1109 struct hlist_node hlist
;
1114 * We make these constant because no one should touch them,
1115 * but they are used as the default "empty hash", to avoid allocating
1116 * it all the time. These are in a read only section such that if
1117 * anyone does try to modify it, it will cause an exception.
1119 static const struct hlist_head empty_buckets
[1];
1120 static const struct ftrace_hash empty_hash
= {
1121 .buckets
= (struct hlist_head
*)empty_buckets
,
1123 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1125 static struct ftrace_ops global_ops
= {
1126 .func
= ftrace_stub
,
1127 .local_hash
.notrace_hash
= EMPTY_HASH
,
1128 .local_hash
.filter_hash
= EMPTY_HASH
,
1129 INIT_OPS_HASH(global_ops
)
1130 .flags
= FTRACE_OPS_FL_RECURSION_SAFE
|
1131 FTRACE_OPS_FL_INITIALIZED
|
1136 * This is used by __kernel_text_address() to return true if the
1137 * address is on a dynamically allocated trampoline that would
1138 * not return true for either core_kernel_text() or
1139 * is_module_text_address().
1141 bool is_ftrace_trampoline(unsigned long addr
)
1143 struct ftrace_ops
*op
;
1147 * Some of the ops may be dynamically allocated,
1148 * they are freed after a synchronize_sched().
1150 preempt_disable_notrace();
1152 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
1154 * This is to check for dynamically allocated trampolines.
1155 * Trampolines that are in kernel text will have
1156 * core_kernel_text() return true.
1158 if (op
->trampoline
&& op
->trampoline_size
)
1159 if (addr
>= op
->trampoline
&&
1160 addr
< op
->trampoline
+ op
->trampoline_size
) {
1164 } while_for_each_ftrace_op(op
);
1167 preempt_enable_notrace();
1172 struct ftrace_page
{
1173 struct ftrace_page
*next
;
1174 struct dyn_ftrace
*records
;
1179 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1180 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1182 /* estimate from running different kernels */
1183 #define NR_TO_INIT 10000
1185 static struct ftrace_page
*ftrace_pages_start
;
1186 static struct ftrace_page
*ftrace_pages
;
1188 static __always_inline
unsigned long
1189 ftrace_hash_key(struct ftrace_hash
*hash
, unsigned long ip
)
1191 if (hash
->size_bits
> 0)
1192 return hash_long(ip
, hash
->size_bits
);
1197 /* Only use this function if ftrace_hash_empty() has already been tested */
1198 static __always_inline
struct ftrace_func_entry
*
1199 __ftrace_lookup_ip(struct ftrace_hash
*hash
, unsigned long ip
)
1202 struct ftrace_func_entry
*entry
;
1203 struct hlist_head
*hhd
;
1205 key
= ftrace_hash_key(hash
, ip
);
1206 hhd
= &hash
->buckets
[key
];
1208 hlist_for_each_entry_rcu_notrace(entry
, hhd
, hlist
) {
1209 if (entry
->ip
== ip
)
1216 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1217 * @hash: The hash to look at
1218 * @ip: The instruction pointer to test
1220 * Search a given @hash to see if a given instruction pointer (@ip)
1223 * Returns the entry that holds the @ip if found. NULL otherwise.
1225 struct ftrace_func_entry
*
1226 ftrace_lookup_ip(struct ftrace_hash
*hash
, unsigned long ip
)
1228 if (ftrace_hash_empty(hash
))
1231 return __ftrace_lookup_ip(hash
, ip
);
1234 static void __add_hash_entry(struct ftrace_hash
*hash
,
1235 struct ftrace_func_entry
*entry
)
1237 struct hlist_head
*hhd
;
1240 key
= ftrace_hash_key(hash
, entry
->ip
);
1241 hhd
= &hash
->buckets
[key
];
1242 hlist_add_head(&entry
->hlist
, hhd
);
1246 static int add_hash_entry(struct ftrace_hash
*hash
, unsigned long ip
)
1248 struct ftrace_func_entry
*entry
;
1250 entry
= kmalloc(sizeof(*entry
), GFP_KERNEL
);
1255 __add_hash_entry(hash
, entry
);
1261 free_hash_entry(struct ftrace_hash
*hash
,
1262 struct ftrace_func_entry
*entry
)
1264 hlist_del(&entry
->hlist
);
1270 remove_hash_entry(struct ftrace_hash
*hash
,
1271 struct ftrace_func_entry
*entry
)
1273 hlist_del(&entry
->hlist
);
1277 static void ftrace_hash_clear(struct ftrace_hash
*hash
)
1279 struct hlist_head
*hhd
;
1280 struct hlist_node
*tn
;
1281 struct ftrace_func_entry
*entry
;
1282 int size
= 1 << hash
->size_bits
;
1288 for (i
= 0; i
< size
; i
++) {
1289 hhd
= &hash
->buckets
[i
];
1290 hlist_for_each_entry_safe(entry
, tn
, hhd
, hlist
)
1291 free_hash_entry(hash
, entry
);
1293 FTRACE_WARN_ON(hash
->count
);
1296 static void free_ftrace_hash(struct ftrace_hash
*hash
)
1298 if (!hash
|| hash
== EMPTY_HASH
)
1300 ftrace_hash_clear(hash
);
1301 kfree(hash
->buckets
);
1305 static void __free_ftrace_hash_rcu(struct rcu_head
*rcu
)
1307 struct ftrace_hash
*hash
;
1309 hash
= container_of(rcu
, struct ftrace_hash
, rcu
);
1310 free_ftrace_hash(hash
);
1313 static void free_ftrace_hash_rcu(struct ftrace_hash
*hash
)
1315 if (!hash
|| hash
== EMPTY_HASH
)
1317 call_rcu_sched(&hash
->rcu
, __free_ftrace_hash_rcu
);
1320 void ftrace_free_filter(struct ftrace_ops
*ops
)
1322 ftrace_ops_init(ops
);
1323 free_ftrace_hash(ops
->func_hash
->filter_hash
);
1324 free_ftrace_hash(ops
->func_hash
->notrace_hash
);
1327 static struct ftrace_hash
*alloc_ftrace_hash(int size_bits
)
1329 struct ftrace_hash
*hash
;
1332 hash
= kzalloc(sizeof(*hash
), GFP_KERNEL
);
1336 size
= 1 << size_bits
;
1337 hash
->buckets
= kcalloc(size
, sizeof(*hash
->buckets
), GFP_KERNEL
);
1339 if (!hash
->buckets
) {
1344 hash
->size_bits
= size_bits
;
1349 static struct ftrace_hash
*
1350 alloc_and_copy_ftrace_hash(int size_bits
, struct ftrace_hash
*hash
)
1352 struct ftrace_func_entry
*entry
;
1353 struct ftrace_hash
*new_hash
;
1358 new_hash
= alloc_ftrace_hash(size_bits
);
1363 if (ftrace_hash_empty(hash
))
1366 size
= 1 << hash
->size_bits
;
1367 for (i
= 0; i
< size
; i
++) {
1368 hlist_for_each_entry(entry
, &hash
->buckets
[i
], hlist
) {
1369 ret
= add_hash_entry(new_hash
, entry
->ip
);
1375 FTRACE_WARN_ON(new_hash
->count
!= hash
->count
);
1380 free_ftrace_hash(new_hash
);
1385 ftrace_hash_rec_disable_modify(struct ftrace_ops
*ops
, int filter_hash
);
1387 ftrace_hash_rec_enable_modify(struct ftrace_ops
*ops
, int filter_hash
);
1389 static int ftrace_hash_ipmodify_update(struct ftrace_ops
*ops
,
1390 struct ftrace_hash
*new_hash
);
1392 static struct ftrace_hash
*
1393 __ftrace_hash_move(struct ftrace_hash
*src
)
1395 struct ftrace_func_entry
*entry
;
1396 struct hlist_node
*tn
;
1397 struct hlist_head
*hhd
;
1398 struct ftrace_hash
*new_hash
;
1399 int size
= src
->count
;
1404 * If the new source is empty, just return the empty_hash.
1410 * Make the hash size about 1/2 the # found
1412 for (size
/= 2; size
; size
>>= 1)
1415 /* Don't allocate too much */
1416 if (bits
> FTRACE_HASH_MAX_BITS
)
1417 bits
= FTRACE_HASH_MAX_BITS
;
1419 new_hash
= alloc_ftrace_hash(bits
);
1423 size
= 1 << src
->size_bits
;
1424 for (i
= 0; i
< size
; i
++) {
1425 hhd
= &src
->buckets
[i
];
1426 hlist_for_each_entry_safe(entry
, tn
, hhd
, hlist
) {
1427 remove_hash_entry(src
, entry
);
1428 __add_hash_entry(new_hash
, entry
);
1436 ftrace_hash_move(struct ftrace_ops
*ops
, int enable
,
1437 struct ftrace_hash
**dst
, struct ftrace_hash
*src
)
1439 struct ftrace_hash
*new_hash
;
1442 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1443 if (ops
->flags
& FTRACE_OPS_FL_IPMODIFY
&& !enable
)
1446 new_hash
= __ftrace_hash_move(src
);
1450 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1452 /* IPMODIFY should be updated only when filter_hash updating */
1453 ret
= ftrace_hash_ipmodify_update(ops
, new_hash
);
1455 free_ftrace_hash(new_hash
);
1461 * Remove the current set, update the hash and add
1464 ftrace_hash_rec_disable_modify(ops
, enable
);
1466 rcu_assign_pointer(*dst
, new_hash
);
1468 ftrace_hash_rec_enable_modify(ops
, enable
);
1473 static bool hash_contains_ip(unsigned long ip
,
1474 struct ftrace_ops_hash
*hash
)
1477 * The function record is a match if it exists in the filter
1478 * hash and not in the notrace hash. Note, an emty hash is
1479 * considered a match for the filter hash, but an empty
1480 * notrace hash is considered not in the notrace hash.
1482 return (ftrace_hash_empty(hash
->filter_hash
) ||
1483 __ftrace_lookup_ip(hash
->filter_hash
, ip
)) &&
1484 (ftrace_hash_empty(hash
->notrace_hash
) ||
1485 !__ftrace_lookup_ip(hash
->notrace_hash
, ip
));
1489 * Test the hashes for this ops to see if we want to call
1490 * the ops->func or not.
1492 * It's a match if the ip is in the ops->filter_hash or
1493 * the filter_hash does not exist or is empty,
1495 * the ip is not in the ops->notrace_hash.
1497 * This needs to be called with preemption disabled as
1498 * the hashes are freed with call_rcu_sched().
1501 ftrace_ops_test(struct ftrace_ops
*ops
, unsigned long ip
, void *regs
)
1503 struct ftrace_ops_hash hash
;
1506 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1508 * There's a small race when adding ops that the ftrace handler
1509 * that wants regs, may be called without them. We can not
1510 * allow that handler to be called if regs is NULL.
1512 if (regs
== NULL
&& (ops
->flags
& FTRACE_OPS_FL_SAVE_REGS
))
1516 hash
.filter_hash
= rcu_dereference_raw_notrace(ops
->func_hash
->filter_hash
);
1517 hash
.notrace_hash
= rcu_dereference_raw_notrace(ops
->func_hash
->notrace_hash
);
1519 if (hash_contains_ip(ip
, &hash
))
1528 * This is a double for. Do not use 'break' to break out of the loop,
1529 * you must use a goto.
1531 #define do_for_each_ftrace_rec(pg, rec) \
1532 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1534 for (_____i = 0; _____i < pg->index; _____i++) { \
1535 rec = &pg->records[_____i];
1537 #define while_for_each_ftrace_rec() \
1542 static int ftrace_cmp_recs(const void *a
, const void *b
)
1544 const struct dyn_ftrace
*key
= a
;
1545 const struct dyn_ftrace
*rec
= b
;
1547 if (key
->flags
< rec
->ip
)
1549 if (key
->ip
>= rec
->ip
+ MCOUNT_INSN_SIZE
)
1555 * ftrace_location_range - return the first address of a traced location
1556 * if it touches the given ip range
1557 * @start: start of range to search.
1558 * @end: end of range to search (inclusive). @end points to the last byte
1561 * Returns rec->ip if the related ftrace location is a least partly within
1562 * the given address range. That is, the first address of the instruction
1563 * that is either a NOP or call to the function tracer. It checks the ftrace
1564 * internal tables to determine if the address belongs or not.
1566 unsigned long ftrace_location_range(unsigned long start
, unsigned long end
)
1568 struct ftrace_page
*pg
;
1569 struct dyn_ftrace
*rec
;
1570 struct dyn_ftrace key
;
1573 key
.flags
= end
; /* overload flags, as it is unsigned long */
1575 for (pg
= ftrace_pages_start
; pg
; pg
= pg
->next
) {
1576 if (end
< pg
->records
[0].ip
||
1577 start
>= (pg
->records
[pg
->index
- 1].ip
+ MCOUNT_INSN_SIZE
))
1579 rec
= bsearch(&key
, pg
->records
, pg
->index
,
1580 sizeof(struct dyn_ftrace
),
1590 * ftrace_location - return true if the ip giving is a traced location
1591 * @ip: the instruction pointer to check
1593 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1594 * That is, the instruction that is either a NOP or call to
1595 * the function tracer. It checks the ftrace internal tables to
1596 * determine if the address belongs or not.
1598 unsigned long ftrace_location(unsigned long ip
)
1600 return ftrace_location_range(ip
, ip
);
1604 * ftrace_text_reserved - return true if range contains an ftrace location
1605 * @start: start of range to search
1606 * @end: end of range to search (inclusive). @end points to the last byte to check.
1608 * Returns 1 if @start and @end contains a ftrace location.
1609 * That is, the instruction that is either a NOP or call to
1610 * the function tracer. It checks the ftrace internal tables to
1611 * determine if the address belongs or not.
1613 int ftrace_text_reserved(const void *start
, const void *end
)
1617 ret
= ftrace_location_range((unsigned long)start
,
1618 (unsigned long)end
);
1623 /* Test if ops registered to this rec needs regs */
1624 static bool test_rec_ops_needs_regs(struct dyn_ftrace
*rec
)
1626 struct ftrace_ops
*ops
;
1627 bool keep_regs
= false;
1629 for (ops
= ftrace_ops_list
;
1630 ops
!= &ftrace_list_end
; ops
= ops
->next
) {
1631 /* pass rec in as regs to have non-NULL val */
1632 if (ftrace_ops_test(ops
, rec
->ip
, rec
)) {
1633 if (ops
->flags
& FTRACE_OPS_FL_SAVE_REGS
) {
1643 static bool __ftrace_hash_rec_update(struct ftrace_ops
*ops
,
1647 struct ftrace_hash
*hash
;
1648 struct ftrace_hash
*other_hash
;
1649 struct ftrace_page
*pg
;
1650 struct dyn_ftrace
*rec
;
1651 bool update
= false;
1655 /* Only update if the ops has been registered */
1656 if (!(ops
->flags
& FTRACE_OPS_FL_ENABLED
))
1660 * In the filter_hash case:
1661 * If the count is zero, we update all records.
1662 * Otherwise we just update the items in the hash.
1664 * In the notrace_hash case:
1665 * We enable the update in the hash.
1666 * As disabling notrace means enabling the tracing,
1667 * and enabling notrace means disabling, the inc variable
1671 hash
= ops
->func_hash
->filter_hash
;
1672 other_hash
= ops
->func_hash
->notrace_hash
;
1673 if (ftrace_hash_empty(hash
))
1677 hash
= ops
->func_hash
->notrace_hash
;
1678 other_hash
= ops
->func_hash
->filter_hash
;
1680 * If the notrace hash has no items,
1681 * then there's nothing to do.
1683 if (ftrace_hash_empty(hash
))
1687 do_for_each_ftrace_rec(pg
, rec
) {
1688 int in_other_hash
= 0;
1692 if (rec
->flags
& FTRACE_FL_DISABLED
)
1697 * Only the filter_hash affects all records.
1698 * Update if the record is not in the notrace hash.
1700 if (!other_hash
|| !ftrace_lookup_ip(other_hash
, rec
->ip
))
1703 in_hash
= !!ftrace_lookup_ip(hash
, rec
->ip
);
1704 in_other_hash
= !!ftrace_lookup_ip(other_hash
, rec
->ip
);
1707 * If filter_hash is set, we want to match all functions
1708 * that are in the hash but not in the other hash.
1710 * If filter_hash is not set, then we are decrementing.
1711 * That means we match anything that is in the hash
1712 * and also in the other_hash. That is, we need to turn
1713 * off functions in the other hash because they are disabled
1716 if (filter_hash
&& in_hash
&& !in_other_hash
)
1718 else if (!filter_hash
&& in_hash
&&
1719 (in_other_hash
|| ftrace_hash_empty(other_hash
)))
1727 if (FTRACE_WARN_ON(ftrace_rec_count(rec
) == FTRACE_REF_MAX
))
1731 * If there's only a single callback registered to a
1732 * function, and the ops has a trampoline registered
1733 * for it, then we can call it directly.
1735 if (ftrace_rec_count(rec
) == 1 && ops
->trampoline
)
1736 rec
->flags
|= FTRACE_FL_TRAMP
;
1739 * If we are adding another function callback
1740 * to this function, and the previous had a
1741 * custom trampoline in use, then we need to go
1742 * back to the default trampoline.
1744 rec
->flags
&= ~FTRACE_FL_TRAMP
;
1747 * If any ops wants regs saved for this function
1748 * then all ops will get saved regs.
1750 if (ops
->flags
& FTRACE_OPS_FL_SAVE_REGS
)
1751 rec
->flags
|= FTRACE_FL_REGS
;
1753 if (FTRACE_WARN_ON(ftrace_rec_count(rec
) == 0))
1758 * If the rec had REGS enabled and the ops that is
1759 * being removed had REGS set, then see if there is
1760 * still any ops for this record that wants regs.
1761 * If not, we can stop recording them.
1763 if (ftrace_rec_count(rec
) > 0 &&
1764 rec
->flags
& FTRACE_FL_REGS
&&
1765 ops
->flags
& FTRACE_OPS_FL_SAVE_REGS
) {
1766 if (!test_rec_ops_needs_regs(rec
))
1767 rec
->flags
&= ~FTRACE_FL_REGS
;
1771 * If the rec had TRAMP enabled, then it needs to
1772 * be cleared. As TRAMP can only be enabled iff
1773 * there is only a single ops attached to it.
1774 * In otherwords, always disable it on decrementing.
1775 * In the future, we may set it if rec count is
1776 * decremented to one, and the ops that is left
1779 rec
->flags
&= ~FTRACE_FL_TRAMP
;
1782 * flags will be cleared in ftrace_check_record()
1783 * if rec count is zero.
1788 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1789 update
|= ftrace_test_record(rec
, 1) != FTRACE_UPDATE_IGNORE
;
1791 /* Shortcut, if we handled all records, we are done. */
1792 if (!all
&& count
== hash
->count
)
1794 } while_for_each_ftrace_rec();
1799 static bool ftrace_hash_rec_disable(struct ftrace_ops
*ops
,
1802 return __ftrace_hash_rec_update(ops
, filter_hash
, 0);
1805 static bool ftrace_hash_rec_enable(struct ftrace_ops
*ops
,
1808 return __ftrace_hash_rec_update(ops
, filter_hash
, 1);
1811 static void ftrace_hash_rec_update_modify(struct ftrace_ops
*ops
,
1812 int filter_hash
, int inc
)
1814 struct ftrace_ops
*op
;
1816 __ftrace_hash_rec_update(ops
, filter_hash
, inc
);
1818 if (ops
->func_hash
!= &global_ops
.local_hash
)
1822 * If the ops shares the global_ops hash, then we need to update
1823 * all ops that are enabled and use this hash.
1825 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
1829 if (op
->func_hash
== &global_ops
.local_hash
)
1830 __ftrace_hash_rec_update(op
, filter_hash
, inc
);
1831 } while_for_each_ftrace_op(op
);
1834 static void ftrace_hash_rec_disable_modify(struct ftrace_ops
*ops
,
1837 ftrace_hash_rec_update_modify(ops
, filter_hash
, 0);
1840 static void ftrace_hash_rec_enable_modify(struct ftrace_ops
*ops
,
1843 ftrace_hash_rec_update_modify(ops
, filter_hash
, 1);
1847 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1848 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1849 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1850 * Note that old_hash and new_hash has below meanings
1851 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1852 * - If the hash is EMPTY_HASH, it hits nothing
1853 * - Anything else hits the recs which match the hash entries.
1855 static int __ftrace_hash_update_ipmodify(struct ftrace_ops
*ops
,
1856 struct ftrace_hash
*old_hash
,
1857 struct ftrace_hash
*new_hash
)
1859 struct ftrace_page
*pg
;
1860 struct dyn_ftrace
*rec
, *end
= NULL
;
1863 /* Only update if the ops has been registered */
1864 if (!(ops
->flags
& FTRACE_OPS_FL_ENABLED
))
1867 if (!(ops
->flags
& FTRACE_OPS_FL_IPMODIFY
))
1871 * Since the IPMODIFY is a very address sensitive action, we do not
1872 * allow ftrace_ops to set all functions to new hash.
1874 if (!new_hash
|| !old_hash
)
1877 /* Update rec->flags */
1878 do_for_each_ftrace_rec(pg
, rec
) {
1880 if (rec
->flags
& FTRACE_FL_DISABLED
)
1883 /* We need to update only differences of filter_hash */
1884 in_old
= !!ftrace_lookup_ip(old_hash
, rec
->ip
);
1885 in_new
= !!ftrace_lookup_ip(new_hash
, rec
->ip
);
1886 if (in_old
== in_new
)
1890 /* New entries must ensure no others are using it */
1891 if (rec
->flags
& FTRACE_FL_IPMODIFY
)
1893 rec
->flags
|= FTRACE_FL_IPMODIFY
;
1894 } else /* Removed entry */
1895 rec
->flags
&= ~FTRACE_FL_IPMODIFY
;
1896 } while_for_each_ftrace_rec();
1903 /* Roll back what we did above */
1904 do_for_each_ftrace_rec(pg
, rec
) {
1906 if (rec
->flags
& FTRACE_FL_DISABLED
)
1912 in_old
= !!ftrace_lookup_ip(old_hash
, rec
->ip
);
1913 in_new
= !!ftrace_lookup_ip(new_hash
, rec
->ip
);
1914 if (in_old
== in_new
)
1918 rec
->flags
&= ~FTRACE_FL_IPMODIFY
;
1920 rec
->flags
|= FTRACE_FL_IPMODIFY
;
1921 } while_for_each_ftrace_rec();
1927 static int ftrace_hash_ipmodify_enable(struct ftrace_ops
*ops
)
1929 struct ftrace_hash
*hash
= ops
->func_hash
->filter_hash
;
1931 if (ftrace_hash_empty(hash
))
1934 return __ftrace_hash_update_ipmodify(ops
, EMPTY_HASH
, hash
);
1937 /* Disabling always succeeds */
1938 static void ftrace_hash_ipmodify_disable(struct ftrace_ops
*ops
)
1940 struct ftrace_hash
*hash
= ops
->func_hash
->filter_hash
;
1942 if (ftrace_hash_empty(hash
))
1945 __ftrace_hash_update_ipmodify(ops
, hash
, EMPTY_HASH
);
1948 static int ftrace_hash_ipmodify_update(struct ftrace_ops
*ops
,
1949 struct ftrace_hash
*new_hash
)
1951 struct ftrace_hash
*old_hash
= ops
->func_hash
->filter_hash
;
1953 if (ftrace_hash_empty(old_hash
))
1956 if (ftrace_hash_empty(new_hash
))
1959 return __ftrace_hash_update_ipmodify(ops
, old_hash
, new_hash
);
1962 static void print_ip_ins(const char *fmt
, const unsigned char *p
)
1966 printk(KERN_CONT
"%s", fmt
);
1968 for (i
= 0; i
< MCOUNT_INSN_SIZE
; i
++)
1969 printk(KERN_CONT
"%s%02x", i
? ":" : "", p
[i
]);
1972 static struct ftrace_ops
*
1973 ftrace_find_tramp_ops_any(struct dyn_ftrace
*rec
);
1974 static struct ftrace_ops
*
1975 ftrace_find_tramp_ops_next(struct dyn_ftrace
*rec
, struct ftrace_ops
*ops
);
1977 enum ftrace_bug_type ftrace_bug_type
;
1978 const void *ftrace_expected
;
1980 static void print_bug_type(void)
1982 switch (ftrace_bug_type
) {
1983 case FTRACE_BUG_UNKNOWN
:
1985 case FTRACE_BUG_INIT
:
1986 pr_info("Initializing ftrace call sites\n");
1988 case FTRACE_BUG_NOP
:
1989 pr_info("Setting ftrace call site to NOP\n");
1991 case FTRACE_BUG_CALL
:
1992 pr_info("Setting ftrace call site to call ftrace function\n");
1994 case FTRACE_BUG_UPDATE
:
1995 pr_info("Updating ftrace call site to call a different ftrace function\n");
2001 * ftrace_bug - report and shutdown function tracer
2002 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2003 * @rec: The record that failed
2005 * The arch code that enables or disables the function tracing
2006 * can call ftrace_bug() when it has detected a problem in
2007 * modifying the code. @failed should be one of either:
2008 * EFAULT - if the problem happens on reading the @ip address
2009 * EINVAL - if what is read at @ip is not what was expected
2010 * EPERM - if the problem happens on writting to the @ip address
2012 void ftrace_bug(int failed
, struct dyn_ftrace
*rec
)
2014 unsigned long ip
= rec
? rec
->ip
: 0;
2018 FTRACE_WARN_ON_ONCE(1);
2019 pr_info("ftrace faulted on modifying ");
2023 FTRACE_WARN_ON_ONCE(1);
2024 pr_info("ftrace failed to modify ");
2026 print_ip_ins(" actual: ", (unsigned char *)ip
);
2028 if (ftrace_expected
) {
2029 print_ip_ins(" expected: ", ftrace_expected
);
2034 FTRACE_WARN_ON_ONCE(1);
2035 pr_info("ftrace faulted on writing ");
2039 FTRACE_WARN_ON_ONCE(1);
2040 pr_info("ftrace faulted on unknown error ");
2045 struct ftrace_ops
*ops
= NULL
;
2047 pr_info("ftrace record flags: %lx\n", rec
->flags
);
2048 pr_cont(" (%ld)%s", ftrace_rec_count(rec
),
2049 rec
->flags
& FTRACE_FL_REGS
? " R" : " ");
2050 if (rec
->flags
& FTRACE_FL_TRAMP_EN
) {
2051 ops
= ftrace_find_tramp_ops_any(rec
);
2054 pr_cont("\ttramp: %pS (%pS)",
2055 (void *)ops
->trampoline
,
2057 ops
= ftrace_find_tramp_ops_next(rec
, ops
);
2060 pr_cont("\ttramp: ERROR!");
2063 ip
= ftrace_get_addr_curr(rec
);
2064 pr_cont("\n expected tramp: %lx\n", ip
);
2068 static int ftrace_check_record(struct dyn_ftrace
*rec
, int enable
, int update
)
2070 unsigned long flag
= 0UL;
2072 ftrace_bug_type
= FTRACE_BUG_UNKNOWN
;
2074 if (rec
->flags
& FTRACE_FL_DISABLED
)
2075 return FTRACE_UPDATE_IGNORE
;
2078 * If we are updating calls:
2080 * If the record has a ref count, then we need to enable it
2081 * because someone is using it.
2083 * Otherwise we make sure its disabled.
2085 * If we are disabling calls, then disable all records that
2088 if (enable
&& ftrace_rec_count(rec
))
2089 flag
= FTRACE_FL_ENABLED
;
2092 * If enabling and the REGS flag does not match the REGS_EN, or
2093 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2094 * this record. Set flags to fail the compare against ENABLED.
2097 if (!(rec
->flags
& FTRACE_FL_REGS
) !=
2098 !(rec
->flags
& FTRACE_FL_REGS_EN
))
2099 flag
|= FTRACE_FL_REGS
;
2101 if (!(rec
->flags
& FTRACE_FL_TRAMP
) !=
2102 !(rec
->flags
& FTRACE_FL_TRAMP_EN
))
2103 flag
|= FTRACE_FL_TRAMP
;
2106 /* If the state of this record hasn't changed, then do nothing */
2107 if ((rec
->flags
& FTRACE_FL_ENABLED
) == flag
)
2108 return FTRACE_UPDATE_IGNORE
;
2111 /* Save off if rec is being enabled (for return value) */
2112 flag
^= rec
->flags
& FTRACE_FL_ENABLED
;
2115 rec
->flags
|= FTRACE_FL_ENABLED
;
2116 if (flag
& FTRACE_FL_REGS
) {
2117 if (rec
->flags
& FTRACE_FL_REGS
)
2118 rec
->flags
|= FTRACE_FL_REGS_EN
;
2120 rec
->flags
&= ~FTRACE_FL_REGS_EN
;
2122 if (flag
& FTRACE_FL_TRAMP
) {
2123 if (rec
->flags
& FTRACE_FL_TRAMP
)
2124 rec
->flags
|= FTRACE_FL_TRAMP_EN
;
2126 rec
->flags
&= ~FTRACE_FL_TRAMP_EN
;
2131 * If this record is being updated from a nop, then
2132 * return UPDATE_MAKE_CALL.
2134 * return UPDATE_MODIFY_CALL to tell the caller to convert
2135 * from the save regs, to a non-save regs function or
2136 * vice versa, or from a trampoline call.
2138 if (flag
& FTRACE_FL_ENABLED
) {
2139 ftrace_bug_type
= FTRACE_BUG_CALL
;
2140 return FTRACE_UPDATE_MAKE_CALL
;
2143 ftrace_bug_type
= FTRACE_BUG_UPDATE
;
2144 return FTRACE_UPDATE_MODIFY_CALL
;
2148 /* If there's no more users, clear all flags */
2149 if (!ftrace_rec_count(rec
))
2153 * Just disable the record, but keep the ops TRAMP
2154 * and REGS states. The _EN flags must be disabled though.
2156 rec
->flags
&= ~(FTRACE_FL_ENABLED
| FTRACE_FL_TRAMP_EN
|
2160 ftrace_bug_type
= FTRACE_BUG_NOP
;
2161 return FTRACE_UPDATE_MAKE_NOP
;
2165 * ftrace_update_record, set a record that now is tracing or not
2166 * @rec: the record to update
2167 * @enable: set to 1 if the record is tracing, zero to force disable
2169 * The records that represent all functions that can be traced need
2170 * to be updated when tracing has been enabled.
2172 int ftrace_update_record(struct dyn_ftrace
*rec
, int enable
)
2174 return ftrace_check_record(rec
, enable
, 1);
2178 * ftrace_test_record, check if the record has been enabled or not
2179 * @rec: the record to test
2180 * @enable: set to 1 to check if enabled, 0 if it is disabled
2182 * The arch code may need to test if a record is already set to
2183 * tracing to determine how to modify the function code that it
2186 int ftrace_test_record(struct dyn_ftrace
*rec
, int enable
)
2188 return ftrace_check_record(rec
, enable
, 0);
2191 static struct ftrace_ops
*
2192 ftrace_find_tramp_ops_any(struct dyn_ftrace
*rec
)
2194 struct ftrace_ops
*op
;
2195 unsigned long ip
= rec
->ip
;
2197 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
2199 if (!op
->trampoline
)
2202 if (hash_contains_ip(ip
, op
->func_hash
))
2204 } while_for_each_ftrace_op(op
);
2209 static struct ftrace_ops
*
2210 ftrace_find_tramp_ops_next(struct dyn_ftrace
*rec
,
2211 struct ftrace_ops
*op
)
2213 unsigned long ip
= rec
->ip
;
2215 while_for_each_ftrace_op(op
) {
2217 if (!op
->trampoline
)
2220 if (hash_contains_ip(ip
, op
->func_hash
))
2227 static struct ftrace_ops
*
2228 ftrace_find_tramp_ops_curr(struct dyn_ftrace
*rec
)
2230 struct ftrace_ops
*op
;
2231 unsigned long ip
= rec
->ip
;
2234 * Need to check removed ops first.
2235 * If they are being removed, and this rec has a tramp,
2236 * and this rec is in the ops list, then it would be the
2237 * one with the tramp.
2240 if (hash_contains_ip(ip
, &removed_ops
->old_hash
))
2245 * Need to find the current trampoline for a rec.
2246 * Now, a trampoline is only attached to a rec if there
2247 * was a single 'ops' attached to it. But this can be called
2248 * when we are adding another op to the rec or removing the
2249 * current one. Thus, if the op is being added, we can
2250 * ignore it because it hasn't attached itself to the rec
2253 * If an ops is being modified (hooking to different functions)
2254 * then we don't care about the new functions that are being
2255 * added, just the old ones (that are probably being removed).
2257 * If we are adding an ops to a function that already is using
2258 * a trampoline, it needs to be removed (trampolines are only
2259 * for single ops connected), then an ops that is not being
2260 * modified also needs to be checked.
2262 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
2264 if (!op
->trampoline
)
2268 * If the ops is being added, it hasn't gotten to
2269 * the point to be removed from this tree yet.
2271 if (op
->flags
& FTRACE_OPS_FL_ADDING
)
2276 * If the ops is being modified and is in the old
2277 * hash, then it is probably being removed from this
2280 if ((op
->flags
& FTRACE_OPS_FL_MODIFYING
) &&
2281 hash_contains_ip(ip
, &op
->old_hash
))
2284 * If the ops is not being added or modified, and it's
2285 * in its normal filter hash, then this must be the one
2288 if (!(op
->flags
& FTRACE_OPS_FL_MODIFYING
) &&
2289 hash_contains_ip(ip
, op
->func_hash
))
2292 } while_for_each_ftrace_op(op
);
2297 static struct ftrace_ops
*
2298 ftrace_find_tramp_ops_new(struct dyn_ftrace
*rec
)
2300 struct ftrace_ops
*op
;
2301 unsigned long ip
= rec
->ip
;
2303 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
2304 /* pass rec in as regs to have non-NULL val */
2305 if (hash_contains_ip(ip
, op
->func_hash
))
2307 } while_for_each_ftrace_op(op
);
2313 * ftrace_get_addr_new - Get the call address to set to
2314 * @rec: The ftrace record descriptor
2316 * If the record has the FTRACE_FL_REGS set, that means that it
2317 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2318 * is not not set, then it wants to convert to the normal callback.
2320 * Returns the address of the trampoline to set to
2322 unsigned long ftrace_get_addr_new(struct dyn_ftrace
*rec
)
2324 struct ftrace_ops
*ops
;
2326 /* Trampolines take precedence over regs */
2327 if (rec
->flags
& FTRACE_FL_TRAMP
) {
2328 ops
= ftrace_find_tramp_ops_new(rec
);
2329 if (FTRACE_WARN_ON(!ops
|| !ops
->trampoline
)) {
2330 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2331 (void *)rec
->ip
, (void *)rec
->ip
, rec
->flags
);
2332 /* Ftrace is shutting down, return anything */
2333 return (unsigned long)FTRACE_ADDR
;
2335 return ops
->trampoline
;
2338 if (rec
->flags
& FTRACE_FL_REGS
)
2339 return (unsigned long)FTRACE_REGS_ADDR
;
2341 return (unsigned long)FTRACE_ADDR
;
2345 * ftrace_get_addr_curr - Get the call address that is already there
2346 * @rec: The ftrace record descriptor
2348 * The FTRACE_FL_REGS_EN is set when the record already points to
2349 * a function that saves all the regs. Basically the '_EN' version
2350 * represents the current state of the function.
2352 * Returns the address of the trampoline that is currently being called
2354 unsigned long ftrace_get_addr_curr(struct dyn_ftrace
*rec
)
2356 struct ftrace_ops
*ops
;
2358 /* Trampolines take precedence over regs */
2359 if (rec
->flags
& FTRACE_FL_TRAMP_EN
) {
2360 ops
= ftrace_find_tramp_ops_curr(rec
);
2361 if (FTRACE_WARN_ON(!ops
)) {
2362 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2363 (void *)rec
->ip
, (void *)rec
->ip
);
2364 /* Ftrace is shutting down, return anything */
2365 return (unsigned long)FTRACE_ADDR
;
2367 return ops
->trampoline
;
2370 if (rec
->flags
& FTRACE_FL_REGS_EN
)
2371 return (unsigned long)FTRACE_REGS_ADDR
;
2373 return (unsigned long)FTRACE_ADDR
;
2377 __ftrace_replace_code(struct dyn_ftrace
*rec
, int enable
)
2379 unsigned long ftrace_old_addr
;
2380 unsigned long ftrace_addr
;
2383 ftrace_addr
= ftrace_get_addr_new(rec
);
2385 /* This needs to be done before we call ftrace_update_record */
2386 ftrace_old_addr
= ftrace_get_addr_curr(rec
);
2388 ret
= ftrace_update_record(rec
, enable
);
2390 ftrace_bug_type
= FTRACE_BUG_UNKNOWN
;
2393 case FTRACE_UPDATE_IGNORE
:
2396 case FTRACE_UPDATE_MAKE_CALL
:
2397 ftrace_bug_type
= FTRACE_BUG_CALL
;
2398 return ftrace_make_call(rec
, ftrace_addr
);
2400 case FTRACE_UPDATE_MAKE_NOP
:
2401 ftrace_bug_type
= FTRACE_BUG_NOP
;
2402 return ftrace_make_nop(NULL
, rec
, ftrace_old_addr
);
2404 case FTRACE_UPDATE_MODIFY_CALL
:
2405 ftrace_bug_type
= FTRACE_BUG_UPDATE
;
2406 return ftrace_modify_call(rec
, ftrace_old_addr
, ftrace_addr
);
2409 return -1; /* unknow ftrace bug */
2412 void __weak
ftrace_replace_code(int enable
)
2414 struct dyn_ftrace
*rec
;
2415 struct ftrace_page
*pg
;
2418 if (unlikely(ftrace_disabled
))
2421 do_for_each_ftrace_rec(pg
, rec
) {
2423 if (rec
->flags
& FTRACE_FL_DISABLED
)
2426 failed
= __ftrace_replace_code(rec
, enable
);
2428 ftrace_bug(failed
, rec
);
2429 /* Stop processing */
2432 } while_for_each_ftrace_rec();
2435 struct ftrace_rec_iter
{
2436 struct ftrace_page
*pg
;
2441 * ftrace_rec_iter_start, start up iterating over traced functions
2443 * Returns an iterator handle that is used to iterate over all
2444 * the records that represent address locations where functions
2447 * May return NULL if no records are available.
2449 struct ftrace_rec_iter
*ftrace_rec_iter_start(void)
2452 * We only use a single iterator.
2453 * Protected by the ftrace_lock mutex.
2455 static struct ftrace_rec_iter ftrace_rec_iter
;
2456 struct ftrace_rec_iter
*iter
= &ftrace_rec_iter
;
2458 iter
->pg
= ftrace_pages_start
;
2461 /* Could have empty pages */
2462 while (iter
->pg
&& !iter
->pg
->index
)
2463 iter
->pg
= iter
->pg
->next
;
2472 * ftrace_rec_iter_next, get the next record to process.
2473 * @iter: The handle to the iterator.
2475 * Returns the next iterator after the given iterator @iter.
2477 struct ftrace_rec_iter
*ftrace_rec_iter_next(struct ftrace_rec_iter
*iter
)
2481 if (iter
->index
>= iter
->pg
->index
) {
2482 iter
->pg
= iter
->pg
->next
;
2485 /* Could have empty pages */
2486 while (iter
->pg
&& !iter
->pg
->index
)
2487 iter
->pg
= iter
->pg
->next
;
2497 * ftrace_rec_iter_record, get the record at the iterator location
2498 * @iter: The current iterator location
2500 * Returns the record that the current @iter is at.
2502 struct dyn_ftrace
*ftrace_rec_iter_record(struct ftrace_rec_iter
*iter
)
2504 return &iter
->pg
->records
[iter
->index
];
2508 ftrace_code_disable(struct module
*mod
, struct dyn_ftrace
*rec
)
2512 if (unlikely(ftrace_disabled
))
2515 ret
= ftrace_make_nop(mod
, rec
, MCOUNT_ADDR
);
2517 ftrace_bug_type
= FTRACE_BUG_INIT
;
2518 ftrace_bug(ret
, rec
);
2525 * archs can override this function if they must do something
2526 * before the modifying code is performed.
2528 int __weak
ftrace_arch_code_modify_prepare(void)
2534 * archs can override this function if they must do something
2535 * after the modifying code is performed.
2537 int __weak
ftrace_arch_code_modify_post_process(void)
2542 void ftrace_modify_all_code(int command
)
2544 int update
= command
& FTRACE_UPDATE_TRACE_FUNC
;
2548 * If the ftrace_caller calls a ftrace_ops func directly,
2549 * we need to make sure that it only traces functions it
2550 * expects to trace. When doing the switch of functions,
2551 * we need to update to the ftrace_ops_list_func first
2552 * before the transition between old and new calls are set,
2553 * as the ftrace_ops_list_func will check the ops hashes
2554 * to make sure the ops are having the right functions
2558 err
= ftrace_update_ftrace_func(ftrace_ops_list_func
);
2559 if (FTRACE_WARN_ON(err
))
2563 if (command
& FTRACE_UPDATE_CALLS
)
2564 ftrace_replace_code(1);
2565 else if (command
& FTRACE_DISABLE_CALLS
)
2566 ftrace_replace_code(0);
2568 if (update
&& ftrace_trace_function
!= ftrace_ops_list_func
) {
2569 function_trace_op
= set_function_trace_op
;
2571 /* If irqs are disabled, we are in stop machine */
2572 if (!irqs_disabled())
2573 smp_call_function(ftrace_sync_ipi
, NULL
, 1);
2574 err
= ftrace_update_ftrace_func(ftrace_trace_function
);
2575 if (FTRACE_WARN_ON(err
))
2579 if (command
& FTRACE_START_FUNC_RET
)
2580 err
= ftrace_enable_ftrace_graph_caller();
2581 else if (command
& FTRACE_STOP_FUNC_RET
)
2582 err
= ftrace_disable_ftrace_graph_caller();
2583 FTRACE_WARN_ON(err
);
2586 static int __ftrace_modify_code(void *data
)
2588 int *command
= data
;
2590 ftrace_modify_all_code(*command
);
2596 * ftrace_run_stop_machine, go back to the stop machine method
2597 * @command: The command to tell ftrace what to do
2599 * If an arch needs to fall back to the stop machine method, the
2600 * it can call this function.
2602 void ftrace_run_stop_machine(int command
)
2604 stop_machine(__ftrace_modify_code
, &command
, NULL
);
2608 * arch_ftrace_update_code, modify the code to trace or not trace
2609 * @command: The command that needs to be done
2611 * Archs can override this function if it does not need to
2612 * run stop_machine() to modify code.
2614 void __weak
arch_ftrace_update_code(int command
)
2616 ftrace_run_stop_machine(command
);
2619 static void ftrace_run_update_code(int command
)
2623 ret
= ftrace_arch_code_modify_prepare();
2624 FTRACE_WARN_ON(ret
);
2629 * By default we use stop_machine() to modify the code.
2630 * But archs can do what ever they want as long as it
2631 * is safe. The stop_machine() is the safest, but also
2632 * produces the most overhead.
2634 arch_ftrace_update_code(command
);
2636 ret
= ftrace_arch_code_modify_post_process();
2637 FTRACE_WARN_ON(ret
);
2640 static void ftrace_run_modify_code(struct ftrace_ops
*ops
, int command
,
2641 struct ftrace_ops_hash
*old_hash
)
2643 ops
->flags
|= FTRACE_OPS_FL_MODIFYING
;
2644 ops
->old_hash
.filter_hash
= old_hash
->filter_hash
;
2645 ops
->old_hash
.notrace_hash
= old_hash
->notrace_hash
;
2646 ftrace_run_update_code(command
);
2647 ops
->old_hash
.filter_hash
= NULL
;
2648 ops
->old_hash
.notrace_hash
= NULL
;
2649 ops
->flags
&= ~FTRACE_OPS_FL_MODIFYING
;
2652 static ftrace_func_t saved_ftrace_func
;
2653 static int ftrace_start_up
;
2655 void __weak
arch_ftrace_trampoline_free(struct ftrace_ops
*ops
)
2659 static void per_cpu_ops_free(struct ftrace_ops
*ops
)
2661 free_percpu(ops
->disabled
);
2664 static void ftrace_startup_enable(int command
)
2666 if (saved_ftrace_func
!= ftrace_trace_function
) {
2667 saved_ftrace_func
= ftrace_trace_function
;
2668 command
|= FTRACE_UPDATE_TRACE_FUNC
;
2671 if (!command
|| !ftrace_enabled
)
2674 ftrace_run_update_code(command
);
2677 static void ftrace_startup_all(int command
)
2679 update_all_ops
= true;
2680 ftrace_startup_enable(command
);
2681 update_all_ops
= false;
2684 static int ftrace_startup(struct ftrace_ops
*ops
, int command
)
2688 if (unlikely(ftrace_disabled
))
2691 ret
= __register_ftrace_function(ops
);
2698 * Note that ftrace probes uses this to start up
2699 * and modify functions it will probe. But we still
2700 * set the ADDING flag for modification, as probes
2701 * do not have trampolines. If they add them in the
2702 * future, then the probes will need to distinguish
2703 * between adding and updating probes.
2705 ops
->flags
|= FTRACE_OPS_FL_ENABLED
| FTRACE_OPS_FL_ADDING
;
2707 ret
= ftrace_hash_ipmodify_enable(ops
);
2709 /* Rollback registration process */
2710 __unregister_ftrace_function(ops
);
2712 ops
->flags
&= ~FTRACE_OPS_FL_ENABLED
;
2716 if (ftrace_hash_rec_enable(ops
, 1))
2717 command
|= FTRACE_UPDATE_CALLS
;
2719 ftrace_startup_enable(command
);
2721 ops
->flags
&= ~FTRACE_OPS_FL_ADDING
;
2726 static int ftrace_shutdown(struct ftrace_ops
*ops
, int command
)
2730 if (unlikely(ftrace_disabled
))
2733 ret
= __unregister_ftrace_function(ops
);
2739 * Just warn in case of unbalance, no need to kill ftrace, it's not
2740 * critical but the ftrace_call callers may be never nopped again after
2741 * further ftrace uses.
2743 WARN_ON_ONCE(ftrace_start_up
< 0);
2745 /* Disabling ipmodify never fails */
2746 ftrace_hash_ipmodify_disable(ops
);
2748 if (ftrace_hash_rec_disable(ops
, 1))
2749 command
|= FTRACE_UPDATE_CALLS
;
2751 ops
->flags
&= ~FTRACE_OPS_FL_ENABLED
;
2753 if (saved_ftrace_func
!= ftrace_trace_function
) {
2754 saved_ftrace_func
= ftrace_trace_function
;
2755 command
|= FTRACE_UPDATE_TRACE_FUNC
;
2758 if (!command
|| !ftrace_enabled
) {
2760 * If these are per_cpu ops, they still need their
2761 * per_cpu field freed. Since, function tracing is
2762 * not currently active, we can just free them
2763 * without synchronizing all CPUs.
2765 if (ops
->flags
& FTRACE_OPS_FL_PER_CPU
)
2766 per_cpu_ops_free(ops
);
2771 * If the ops uses a trampoline, then it needs to be
2772 * tested first on update.
2774 ops
->flags
|= FTRACE_OPS_FL_REMOVING
;
2777 /* The trampoline logic checks the old hashes */
2778 ops
->old_hash
.filter_hash
= ops
->func_hash
->filter_hash
;
2779 ops
->old_hash
.notrace_hash
= ops
->func_hash
->notrace_hash
;
2781 ftrace_run_update_code(command
);
2784 * If there's no more ops registered with ftrace, run a
2785 * sanity check to make sure all rec flags are cleared.
2787 if (ftrace_ops_list
== &ftrace_list_end
) {
2788 struct ftrace_page
*pg
;
2789 struct dyn_ftrace
*rec
;
2791 do_for_each_ftrace_rec(pg
, rec
) {
2792 if (FTRACE_WARN_ON_ONCE(rec
->flags
& ~FTRACE_FL_DISABLED
))
2793 pr_warn(" %pS flags:%lx\n",
2794 (void *)rec
->ip
, rec
->flags
);
2795 } while_for_each_ftrace_rec();
2798 ops
->old_hash
.filter_hash
= NULL
;
2799 ops
->old_hash
.notrace_hash
= NULL
;
2802 ops
->flags
&= ~FTRACE_OPS_FL_REMOVING
;
2805 * Dynamic ops may be freed, we must make sure that all
2806 * callers are done before leaving this function.
2807 * The same goes for freeing the per_cpu data of the per_cpu
2810 * Again, normal synchronize_sched() is not good enough.
2811 * We need to do a hard force of sched synchronization.
2812 * This is because we use preempt_disable() to do RCU, but
2813 * the function tracers can be called where RCU is not watching
2814 * (like before user_exit()). We can not rely on the RCU
2815 * infrastructure to do the synchronization, thus we must do it
2818 if (ops
->flags
& (FTRACE_OPS_FL_DYNAMIC
| FTRACE_OPS_FL_PER_CPU
)) {
2819 schedule_on_each_cpu(ftrace_sync
);
2821 arch_ftrace_trampoline_free(ops
);
2823 if (ops
->flags
& FTRACE_OPS_FL_PER_CPU
)
2824 per_cpu_ops_free(ops
);
2830 static void ftrace_startup_sysctl(void)
2834 if (unlikely(ftrace_disabled
))
2837 /* Force update next time */
2838 saved_ftrace_func
= NULL
;
2839 /* ftrace_start_up is true if we want ftrace running */
2840 if (ftrace_start_up
) {
2841 command
= FTRACE_UPDATE_CALLS
;
2842 if (ftrace_graph_active
)
2843 command
|= FTRACE_START_FUNC_RET
;
2844 ftrace_startup_enable(command
);
2848 static void ftrace_shutdown_sysctl(void)
2852 if (unlikely(ftrace_disabled
))
2855 /* ftrace_start_up is true if ftrace is running */
2856 if (ftrace_start_up
) {
2857 command
= FTRACE_DISABLE_CALLS
;
2858 if (ftrace_graph_active
)
2859 command
|= FTRACE_STOP_FUNC_RET
;
2860 ftrace_run_update_code(command
);
2864 static u64 ftrace_update_time
;
2865 unsigned long ftrace_update_tot_cnt
;
2867 static inline int ops_traces_mod(struct ftrace_ops
*ops
)
2870 * Filter_hash being empty will default to trace module.
2871 * But notrace hash requires a test of individual module functions.
2873 return ftrace_hash_empty(ops
->func_hash
->filter_hash
) &&
2874 ftrace_hash_empty(ops
->func_hash
->notrace_hash
);
2878 * Check if the current ops references the record.
2880 * If the ops traces all functions, then it was already accounted for.
2881 * If the ops does not trace the current record function, skip it.
2882 * If the ops ignores the function via notrace filter, skip it.
2885 ops_references_rec(struct ftrace_ops
*ops
, struct dyn_ftrace
*rec
)
2887 /* If ops isn't enabled, ignore it */
2888 if (!(ops
->flags
& FTRACE_OPS_FL_ENABLED
))
2891 /* If ops traces all then it includes this function */
2892 if (ops_traces_mod(ops
))
2895 /* The function must be in the filter */
2896 if (!ftrace_hash_empty(ops
->func_hash
->filter_hash
) &&
2897 !__ftrace_lookup_ip(ops
->func_hash
->filter_hash
, rec
->ip
))
2900 /* If in notrace hash, we ignore it too */
2901 if (ftrace_lookup_ip(ops
->func_hash
->notrace_hash
, rec
->ip
))
2907 static int ftrace_update_code(struct module
*mod
, struct ftrace_page
*new_pgs
)
2909 struct ftrace_page
*pg
;
2910 struct dyn_ftrace
*p
;
2912 unsigned long update_cnt
= 0;
2913 unsigned long rec_flags
= 0;
2916 start
= ftrace_now(raw_smp_processor_id());
2919 * When a module is loaded, this function is called to convert
2920 * the calls to mcount in its text to nops, and also to create
2921 * an entry in the ftrace data. Now, if ftrace is activated
2922 * after this call, but before the module sets its text to
2923 * read-only, the modification of enabling ftrace can fail if
2924 * the read-only is done while ftrace is converting the calls.
2925 * To prevent this, the module's records are set as disabled
2926 * and will be enabled after the call to set the module's text
2930 rec_flags
|= FTRACE_FL_DISABLED
;
2932 for (pg
= new_pgs
; pg
; pg
= pg
->next
) {
2934 for (i
= 0; i
< pg
->index
; i
++) {
2936 /* If something went wrong, bail without enabling anything */
2937 if (unlikely(ftrace_disabled
))
2940 p
= &pg
->records
[i
];
2941 p
->flags
= rec_flags
;
2944 * Do the initial record conversion from mcount jump
2945 * to the NOP instructions.
2947 if (!ftrace_code_disable(mod
, p
))
2954 stop
= ftrace_now(raw_smp_processor_id());
2955 ftrace_update_time
= stop
- start
;
2956 ftrace_update_tot_cnt
+= update_cnt
;
2961 static int ftrace_allocate_records(struct ftrace_page
*pg
, int count
)
2966 if (WARN_ON(!count
))
2969 order
= get_count_order(DIV_ROUND_UP(count
, ENTRIES_PER_PAGE
));
2972 * We want to fill as much as possible. No more than a page
2975 while ((PAGE_SIZE
<< order
) / ENTRY_SIZE
>= count
+ ENTRIES_PER_PAGE
)
2979 pg
->records
= (void *)__get_free_pages(GFP_KERNEL
| __GFP_ZERO
, order
);
2982 /* if we can't allocate this size, try something smaller */
2989 cnt
= (PAGE_SIZE
<< order
) / ENTRY_SIZE
;
2998 static struct ftrace_page
*
2999 ftrace_allocate_pages(unsigned long num_to_init
)
3001 struct ftrace_page
*start_pg
;
3002 struct ftrace_page
*pg
;
3009 start_pg
= pg
= kzalloc(sizeof(*pg
), GFP_KERNEL
);
3014 * Try to allocate as much as possible in one continues
3015 * location that fills in all of the space. We want to
3016 * waste as little space as possible.
3019 cnt
= ftrace_allocate_records(pg
, num_to_init
);
3027 pg
->next
= kzalloc(sizeof(*pg
), GFP_KERNEL
);
3039 order
= get_count_order(pg
->size
/ ENTRIES_PER_PAGE
);
3040 free_pages((unsigned long)pg
->records
, order
);
3041 start_pg
= pg
->next
;
3045 pr_info("ftrace: FAILED to allocate memory for functions\n");
3049 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3051 struct ftrace_iterator
{
3054 struct ftrace_page
*pg
;
3055 struct dyn_ftrace
*func
;
3056 struct ftrace_func_probe
*probe
;
3057 struct trace_parser parser
;
3058 struct ftrace_hash
*hash
;
3059 struct ftrace_ops
*ops
;
3066 t_hash_next(struct seq_file
*m
, loff_t
*pos
)
3068 struct ftrace_iterator
*iter
= m
->private;
3069 struct hlist_node
*hnd
= NULL
;
3070 struct hlist_head
*hhd
;
3076 hnd
= &iter
->probe
->node
;
3078 if (iter
->hidx
>= FTRACE_FUNC_HASHSIZE
)
3081 hhd
= &ftrace_func_hash
[iter
->hidx
];
3083 if (hlist_empty(hhd
)) {
3099 if (WARN_ON_ONCE(!hnd
))
3102 iter
->probe
= hlist_entry(hnd
, struct ftrace_func_probe
, node
);
3107 static void *t_hash_start(struct seq_file
*m
, loff_t
*pos
)
3109 struct ftrace_iterator
*iter
= m
->private;
3113 if (!(iter
->flags
& FTRACE_ITER_DO_HASH
))
3116 if (iter
->func_pos
> *pos
)
3120 for (l
= 0; l
<= (*pos
- iter
->func_pos
); ) {
3121 p
= t_hash_next(m
, &l
);
3128 /* Only set this if we have an item */
3129 iter
->flags
|= FTRACE_ITER_HASH
;
3135 t_hash_show(struct seq_file
*m
, struct ftrace_iterator
*iter
)
3137 struct ftrace_func_probe
*rec
;
3140 if (WARN_ON_ONCE(!rec
))
3143 if (rec
->ops
->print
)
3144 return rec
->ops
->print(m
, rec
->ip
, rec
->ops
, rec
->data
);
3146 seq_printf(m
, "%ps:%ps", (void *)rec
->ip
, (void *)rec
->ops
->func
);
3149 seq_printf(m
, ":%p", rec
->data
);
3156 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
3158 struct ftrace_iterator
*iter
= m
->private;
3159 struct ftrace_ops
*ops
= iter
->ops
;
3160 struct dyn_ftrace
*rec
= NULL
;
3162 if (unlikely(ftrace_disabled
))
3165 if (iter
->flags
& FTRACE_ITER_HASH
)
3166 return t_hash_next(m
, pos
);
3169 iter
->pos
= iter
->func_pos
= *pos
;
3171 if (iter
->flags
& FTRACE_ITER_PRINTALL
)
3172 return t_hash_start(m
, pos
);
3175 if (iter
->idx
>= iter
->pg
->index
) {
3176 if (iter
->pg
->next
) {
3177 iter
->pg
= iter
->pg
->next
;
3182 rec
= &iter
->pg
->records
[iter
->idx
++];
3183 if (((iter
->flags
& FTRACE_ITER_FILTER
) &&
3184 !(ftrace_lookup_ip(ops
->func_hash
->filter_hash
, rec
->ip
))) ||
3186 ((iter
->flags
& FTRACE_ITER_NOTRACE
) &&
3187 !ftrace_lookup_ip(ops
->func_hash
->notrace_hash
, rec
->ip
)) ||
3189 ((iter
->flags
& FTRACE_ITER_ENABLED
) &&
3190 !(rec
->flags
& FTRACE_FL_ENABLED
))) {
3198 return t_hash_start(m
, pos
);
3205 static void reset_iter_read(struct ftrace_iterator
*iter
)
3209 iter
->flags
&= ~(FTRACE_ITER_PRINTALL
| FTRACE_ITER_HASH
);
3212 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
3214 struct ftrace_iterator
*iter
= m
->private;
3215 struct ftrace_ops
*ops
= iter
->ops
;
3219 mutex_lock(&ftrace_lock
);
3221 if (unlikely(ftrace_disabled
))
3225 * If an lseek was done, then reset and start from beginning.
3227 if (*pos
< iter
->pos
)
3228 reset_iter_read(iter
);
3231 * For set_ftrace_filter reading, if we have the filter
3232 * off, we can short cut and just print out that all
3233 * functions are enabled.
3235 if ((iter
->flags
& FTRACE_ITER_FILTER
&&
3236 ftrace_hash_empty(ops
->func_hash
->filter_hash
)) ||
3237 (iter
->flags
& FTRACE_ITER_NOTRACE
&&
3238 ftrace_hash_empty(ops
->func_hash
->notrace_hash
))) {
3240 return t_hash_start(m
, pos
);
3241 iter
->flags
|= FTRACE_ITER_PRINTALL
;
3242 /* reset in case of seek/pread */
3243 iter
->flags
&= ~FTRACE_ITER_HASH
;
3247 if (iter
->flags
& FTRACE_ITER_HASH
)
3248 return t_hash_start(m
, pos
);
3251 * Unfortunately, we need to restart at ftrace_pages_start
3252 * every time we let go of the ftrace_mutex. This is because
3253 * those pointers can change without the lock.
3255 iter
->pg
= ftrace_pages_start
;
3257 for (l
= 0; l
<= *pos
; ) {
3258 p
= t_next(m
, p
, &l
);
3264 return t_hash_start(m
, pos
);
3269 static void t_stop(struct seq_file
*m
, void *p
)
3271 mutex_unlock(&ftrace_lock
);
3275 arch_ftrace_trampoline_func(struct ftrace_ops
*ops
, struct dyn_ftrace
*rec
)
3280 static void add_trampoline_func(struct seq_file
*m
, struct ftrace_ops
*ops
,
3281 struct dyn_ftrace
*rec
)
3285 ptr
= arch_ftrace_trampoline_func(ops
, rec
);
3287 seq_printf(m
, " ->%pS", ptr
);
3290 static int t_show(struct seq_file
*m
, void *v
)
3292 struct ftrace_iterator
*iter
= m
->private;
3293 struct dyn_ftrace
*rec
;
3295 if (iter
->flags
& FTRACE_ITER_HASH
)
3296 return t_hash_show(m
, iter
);
3298 if (iter
->flags
& FTRACE_ITER_PRINTALL
) {
3299 if (iter
->flags
& FTRACE_ITER_NOTRACE
)
3300 seq_puts(m
, "#### no functions disabled ####\n");
3302 seq_puts(m
, "#### all functions enabled ####\n");
3311 seq_printf(m
, "%ps", (void *)rec
->ip
);
3312 if (iter
->flags
& FTRACE_ITER_ENABLED
) {
3313 struct ftrace_ops
*ops
;
3315 seq_printf(m
, " (%ld)%s%s",
3316 ftrace_rec_count(rec
),
3317 rec
->flags
& FTRACE_FL_REGS
? " R" : " ",
3318 rec
->flags
& FTRACE_FL_IPMODIFY
? " I" : " ");
3319 if (rec
->flags
& FTRACE_FL_TRAMP_EN
) {
3320 ops
= ftrace_find_tramp_ops_any(rec
);
3323 seq_printf(m
, "\ttramp: %pS (%pS)",
3324 (void *)ops
->trampoline
,
3326 add_trampoline_func(m
, ops
, rec
);
3327 ops
= ftrace_find_tramp_ops_next(rec
, ops
);
3330 seq_puts(m
, "\ttramp: ERROR!");
3332 add_trampoline_func(m
, NULL
, rec
);
3341 static const struct seq_operations show_ftrace_seq_ops
= {
3349 ftrace_avail_open(struct inode
*inode
, struct file
*file
)
3351 struct ftrace_iterator
*iter
;
3353 if (unlikely(ftrace_disabled
))
3356 iter
= __seq_open_private(file
, &show_ftrace_seq_ops
, sizeof(*iter
));
3358 iter
->pg
= ftrace_pages_start
;
3359 iter
->ops
= &global_ops
;
3362 return iter
? 0 : -ENOMEM
;
3366 ftrace_enabled_open(struct inode
*inode
, struct file
*file
)
3368 struct ftrace_iterator
*iter
;
3370 iter
= __seq_open_private(file
, &show_ftrace_seq_ops
, sizeof(*iter
));
3372 iter
->pg
= ftrace_pages_start
;
3373 iter
->flags
= FTRACE_ITER_ENABLED
;
3374 iter
->ops
= &global_ops
;
3377 return iter
? 0 : -ENOMEM
;
3381 * ftrace_regex_open - initialize function tracer filter files
3382 * @ops: The ftrace_ops that hold the hash filters
3383 * @flag: The type of filter to process
3384 * @inode: The inode, usually passed in to your open routine
3385 * @file: The file, usually passed in to your open routine
3387 * ftrace_regex_open() initializes the filter files for the
3388 * @ops. Depending on @flag it may process the filter hash or
3389 * the notrace hash of @ops. With this called from the open
3390 * routine, you can use ftrace_filter_write() for the write
3391 * routine if @flag has FTRACE_ITER_FILTER set, or
3392 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3393 * tracing_lseek() should be used as the lseek routine, and
3394 * release must call ftrace_regex_release().
3397 ftrace_regex_open(struct ftrace_ops
*ops
, int flag
,
3398 struct inode
*inode
, struct file
*file
)
3400 struct ftrace_iterator
*iter
;
3401 struct ftrace_hash
*hash
;
3404 ftrace_ops_init(ops
);
3406 if (unlikely(ftrace_disabled
))
3409 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
3413 if (trace_parser_get_init(&iter
->parser
, FTRACE_BUFF_MAX
)) {
3421 mutex_lock(&ops
->func_hash
->regex_lock
);
3423 if (flag
& FTRACE_ITER_NOTRACE
)
3424 hash
= ops
->func_hash
->notrace_hash
;
3426 hash
= ops
->func_hash
->filter_hash
;
3428 if (file
->f_mode
& FMODE_WRITE
) {
3429 const int size_bits
= FTRACE_HASH_DEFAULT_BITS
;
3431 if (file
->f_flags
& O_TRUNC
)
3432 iter
->hash
= alloc_ftrace_hash(size_bits
);
3434 iter
->hash
= alloc_and_copy_ftrace_hash(size_bits
, hash
);
3437 trace_parser_put(&iter
->parser
);
3444 if (file
->f_mode
& FMODE_READ
) {
3445 iter
->pg
= ftrace_pages_start
;
3447 ret
= seq_open(file
, &show_ftrace_seq_ops
);
3449 struct seq_file
*m
= file
->private_data
;
3453 free_ftrace_hash(iter
->hash
);
3454 trace_parser_put(&iter
->parser
);
3458 file
->private_data
= iter
;
3461 mutex_unlock(&ops
->func_hash
->regex_lock
);
3467 ftrace_filter_open(struct inode
*inode
, struct file
*file
)
3469 struct ftrace_ops
*ops
= inode
->i_private
;
3471 return ftrace_regex_open(ops
,
3472 FTRACE_ITER_FILTER
| FTRACE_ITER_DO_HASH
,
3477 ftrace_notrace_open(struct inode
*inode
, struct file
*file
)
3479 struct ftrace_ops
*ops
= inode
->i_private
;
3481 return ftrace_regex_open(ops
, FTRACE_ITER_NOTRACE
,
3485 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3486 struct ftrace_glob
{
3493 * If symbols in an architecture don't correspond exactly to the user-visible
3494 * name of what they represent, it is possible to define this function to
3495 * perform the necessary adjustments.
3497 char * __weak
arch_ftrace_match_adjust(char *str
, const char *search
)
3502 static int ftrace_match(char *str
, struct ftrace_glob
*g
)
3507 str
= arch_ftrace_match_adjust(str
, g
->search
);
3511 if (strcmp(str
, g
->search
) == 0)
3514 case MATCH_FRONT_ONLY
:
3515 if (strncmp(str
, g
->search
, g
->len
) == 0)
3518 case MATCH_MIDDLE_ONLY
:
3519 if (strstr(str
, g
->search
))
3522 case MATCH_END_ONLY
:
3524 if (slen
>= g
->len
&&
3525 memcmp(str
+ slen
- g
->len
, g
->search
, g
->len
) == 0)
3529 if (glob_match(g
->search
, str
))
3538 enter_record(struct ftrace_hash
*hash
, struct dyn_ftrace
*rec
, int clear_filter
)
3540 struct ftrace_func_entry
*entry
;
3543 entry
= ftrace_lookup_ip(hash
, rec
->ip
);
3545 /* Do nothing if it doesn't exist */
3549 free_hash_entry(hash
, entry
);
3551 /* Do nothing if it exists */
3555 ret
= add_hash_entry(hash
, rec
->ip
);
3561 ftrace_match_record(struct dyn_ftrace
*rec
, struct ftrace_glob
*func_g
,
3562 struct ftrace_glob
*mod_g
, int exclude_mod
)
3564 char str
[KSYM_SYMBOL_LEN
];
3567 kallsyms_lookup(rec
->ip
, NULL
, NULL
, &modname
, str
);
3570 int mod_matches
= (modname
) ? ftrace_match(modname
, mod_g
) : 0;
3572 /* blank module name to match all modules */
3574 /* blank module globbing: modname xor exclude_mod */
3575 if ((!exclude_mod
) != (!modname
))
3580 /* not matching the module */
3581 if (!modname
|| !mod_matches
) {
3588 if (mod_matches
&& exclude_mod
)
3592 /* blank search means to match all funcs in the mod */
3597 return ftrace_match(str
, func_g
);
3601 match_records(struct ftrace_hash
*hash
, char *func
, int len
, char *mod
)
3603 struct ftrace_page
*pg
;
3604 struct dyn_ftrace
*rec
;
3605 struct ftrace_glob func_g
= { .type
= MATCH_FULL
};
3606 struct ftrace_glob mod_g
= { .type
= MATCH_FULL
};
3607 struct ftrace_glob
*mod_match
= (mod
) ? &mod_g
: NULL
;
3608 int exclude_mod
= 0;
3614 func_g
.type
= filter_parse_regex(func
, len
, &func_g
.search
,
3616 func_g
.len
= strlen(func_g
.search
);
3620 mod_g
.type
= filter_parse_regex(mod
, strlen(mod
),
3621 &mod_g
.search
, &exclude_mod
);
3622 mod_g
.len
= strlen(mod_g
.search
);
3625 mutex_lock(&ftrace_lock
);
3627 if (unlikely(ftrace_disabled
))
3630 do_for_each_ftrace_rec(pg
, rec
) {
3632 if (rec
->flags
& FTRACE_FL_DISABLED
)
3635 if (ftrace_match_record(rec
, &func_g
, mod_match
, exclude_mod
)) {
3636 ret
= enter_record(hash
, rec
, clear_filter
);
3643 } while_for_each_ftrace_rec();
3645 mutex_unlock(&ftrace_lock
);
3651 ftrace_match_records(struct ftrace_hash
*hash
, char *buff
, int len
)
3653 return match_records(hash
, buff
, len
, NULL
);
3658 * We register the module command as a template to show others how
3659 * to register the a command as well.
3663 ftrace_mod_callback(struct ftrace_hash
*hash
,
3664 char *func
, char *cmd
, char *module
, int enable
)
3669 * cmd == 'mod' because we only registered this func
3670 * for the 'mod' ftrace_func_command.
3671 * But if you register one func with multiple commands,
3672 * you can tell which command was used by the cmd
3675 ret
= match_records(hash
, func
, strlen(func
), module
);
3683 static struct ftrace_func_command ftrace_mod_cmd
= {
3685 .func
= ftrace_mod_callback
,
3688 static int __init
ftrace_mod_cmd_init(void)
3690 return register_ftrace_command(&ftrace_mod_cmd
);
3692 core_initcall(ftrace_mod_cmd_init
);
3694 static void function_trace_probe_call(unsigned long ip
, unsigned long parent_ip
,
3695 struct ftrace_ops
*op
, struct pt_regs
*pt_regs
)
3697 struct ftrace_func_probe
*entry
;
3698 struct hlist_head
*hhd
;
3701 key
= hash_long(ip
, FTRACE_HASH_BITS
);
3703 hhd
= &ftrace_func_hash
[key
];
3705 if (hlist_empty(hhd
))
3709 * Disable preemption for these calls to prevent a RCU grace
3710 * period. This syncs the hash iteration and freeing of items
3711 * on the hash. rcu_read_lock is too dangerous here.
3713 preempt_disable_notrace();
3714 hlist_for_each_entry_rcu_notrace(entry
, hhd
, node
) {
3715 if (entry
->ip
== ip
)
3716 entry
->ops
->func(ip
, parent_ip
, &entry
->data
);
3718 preempt_enable_notrace();
3721 static struct ftrace_ops trace_probe_ops __read_mostly
=
3723 .func
= function_trace_probe_call
,
3724 .flags
= FTRACE_OPS_FL_INITIALIZED
,
3725 INIT_OPS_HASH(trace_probe_ops
)
3728 static int ftrace_probe_registered
;
3730 static void __enable_ftrace_function_probe(struct ftrace_ops_hash
*old_hash
)
3735 if (ftrace_probe_registered
) {
3736 /* still need to update the function call sites */
3738 ftrace_run_modify_code(&trace_probe_ops
, FTRACE_UPDATE_CALLS
,
3743 for (i
= 0; i
< FTRACE_FUNC_HASHSIZE
; i
++) {
3744 struct hlist_head
*hhd
= &ftrace_func_hash
[i
];
3748 /* Nothing registered? */
3749 if (i
== FTRACE_FUNC_HASHSIZE
)
3752 ret
= ftrace_startup(&trace_probe_ops
, 0);
3754 ftrace_probe_registered
= 1;
3757 static void __disable_ftrace_function_probe(void)
3761 if (!ftrace_probe_registered
)
3764 for (i
= 0; i
< FTRACE_FUNC_HASHSIZE
; i
++) {
3765 struct hlist_head
*hhd
= &ftrace_func_hash
[i
];
3770 /* no more funcs left */
3771 ftrace_shutdown(&trace_probe_ops
, 0);
3773 ftrace_probe_registered
= 0;
3777 static void ftrace_free_entry(struct ftrace_func_probe
*entry
)
3779 if (entry
->ops
->free
)
3780 entry
->ops
->free(entry
->ops
, entry
->ip
, &entry
->data
);
3785 register_ftrace_function_probe(char *glob
, struct ftrace_probe_ops
*ops
,
3788 struct ftrace_ops_hash old_hash_ops
;
3789 struct ftrace_func_probe
*entry
;
3790 struct ftrace_glob func_g
;
3791 struct ftrace_hash
**orig_hash
= &trace_probe_ops
.func_hash
->filter_hash
;
3792 struct ftrace_hash
*old_hash
= *orig_hash
;
3793 struct ftrace_hash
*hash
;
3794 struct ftrace_page
*pg
;
3795 struct dyn_ftrace
*rec
;
3801 func_g
.type
= filter_parse_regex(glob
, strlen(glob
),
3802 &func_g
.search
, ¬);
3803 func_g
.len
= strlen(func_g
.search
);
3805 /* we do not support '!' for function probes */
3809 mutex_lock(&trace_probe_ops
.func_hash
->regex_lock
);
3811 old_hash_ops
.filter_hash
= old_hash
;
3812 /* Probes only have filters */
3813 old_hash_ops
.notrace_hash
= NULL
;
3815 hash
= alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
, old_hash
);
3821 if (unlikely(ftrace_disabled
)) {
3826 mutex_lock(&ftrace_lock
);
3828 do_for_each_ftrace_rec(pg
, rec
) {
3830 if (rec
->flags
& FTRACE_FL_DISABLED
)
3833 if (!ftrace_match_record(rec
, &func_g
, NULL
, 0))
3836 entry
= kmalloc(sizeof(*entry
), GFP_KERNEL
);
3838 /* If we did not process any, then return error */
3849 * The caller might want to do something special
3850 * for each function we find. We call the callback
3851 * to give the caller an opportunity to do so.
3854 if (ops
->init(ops
, rec
->ip
, &entry
->data
) < 0) {
3855 /* caller does not like this func */
3861 ret
= enter_record(hash
, rec
, 0);
3869 entry
->ip
= rec
->ip
;
3871 key
= hash_long(entry
->ip
, FTRACE_HASH_BITS
);
3872 hlist_add_head_rcu(&entry
->node
, &ftrace_func_hash
[key
]);
3874 } while_for_each_ftrace_rec();
3876 ret
= ftrace_hash_move(&trace_probe_ops
, 1, orig_hash
, hash
);
3878 __enable_ftrace_function_probe(&old_hash_ops
);
3881 free_ftrace_hash_rcu(old_hash
);
3886 mutex_unlock(&ftrace_lock
);
3888 mutex_unlock(&trace_probe_ops
.func_hash
->regex_lock
);
3889 free_ftrace_hash(hash
);
3895 PROBE_TEST_FUNC
= 1,
3900 __unregister_ftrace_function_probe(char *glob
, struct ftrace_probe_ops
*ops
,
3901 void *data
, int flags
)
3903 struct ftrace_func_entry
*rec_entry
;
3904 struct ftrace_func_probe
*entry
;
3905 struct ftrace_func_probe
*p
;
3906 struct ftrace_glob func_g
;
3907 struct ftrace_hash
**orig_hash
= &trace_probe_ops
.func_hash
->filter_hash
;
3908 struct ftrace_hash
*old_hash
= *orig_hash
;
3909 struct list_head free_list
;
3910 struct ftrace_hash
*hash
;
3911 struct hlist_node
*tmp
;
3912 char str
[KSYM_SYMBOL_LEN
];
3915 if (glob
&& (strcmp(glob
, "*") == 0 || !strlen(glob
)))
3916 func_g
.search
= NULL
;
3920 func_g
.type
= filter_parse_regex(glob
, strlen(glob
),
3921 &func_g
.search
, ¬);
3922 func_g
.len
= strlen(func_g
.search
);
3923 func_g
.search
= glob
;
3925 /* we do not support '!' for function probes */
3930 mutex_lock(&trace_probe_ops
.func_hash
->regex_lock
);
3932 hash
= alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
, *orig_hash
);
3934 /* Hmm, should report this somehow */
3937 INIT_LIST_HEAD(&free_list
);
3939 for (i
= 0; i
< FTRACE_FUNC_HASHSIZE
; i
++) {
3940 struct hlist_head
*hhd
= &ftrace_func_hash
[i
];
3942 hlist_for_each_entry_safe(entry
, tmp
, hhd
, node
) {
3944 /* break up if statements for readability */
3945 if ((flags
& PROBE_TEST_FUNC
) && entry
->ops
!= ops
)
3948 if ((flags
& PROBE_TEST_DATA
) && entry
->data
!= data
)
3951 /* do this last, since it is the most expensive */
3952 if (func_g
.search
) {
3953 kallsyms_lookup(entry
->ip
, NULL
, NULL
,
3955 if (!ftrace_match(str
, &func_g
))
3959 rec_entry
= ftrace_lookup_ip(hash
, entry
->ip
);
3960 /* It is possible more than one entry had this ip */
3962 free_hash_entry(hash
, rec_entry
);
3964 hlist_del_rcu(&entry
->node
);
3965 list_add(&entry
->free_list
, &free_list
);
3968 mutex_lock(&ftrace_lock
);
3969 __disable_ftrace_function_probe();
3971 * Remove after the disable is called. Otherwise, if the last
3972 * probe is removed, a null hash means *all enabled*.
3974 ret
= ftrace_hash_move(&trace_probe_ops
, 1, orig_hash
, hash
);
3975 synchronize_sched();
3977 free_ftrace_hash_rcu(old_hash
);
3979 list_for_each_entry_safe(entry
, p
, &free_list
, free_list
) {
3980 list_del(&entry
->free_list
);
3981 ftrace_free_entry(entry
);
3983 mutex_unlock(&ftrace_lock
);
3986 mutex_unlock(&trace_probe_ops
.func_hash
->regex_lock
);
3987 free_ftrace_hash(hash
);
3991 unregister_ftrace_function_probe(char *glob
, struct ftrace_probe_ops
*ops
,
3994 __unregister_ftrace_function_probe(glob
, ops
, data
,
3995 PROBE_TEST_FUNC
| PROBE_TEST_DATA
);
3999 unregister_ftrace_function_probe_func(char *glob
, struct ftrace_probe_ops
*ops
)
4001 __unregister_ftrace_function_probe(glob
, ops
, NULL
, PROBE_TEST_FUNC
);
4004 void unregister_ftrace_function_probe_all(char *glob
)
4006 __unregister_ftrace_function_probe(glob
, NULL
, NULL
, 0);
4009 static LIST_HEAD(ftrace_commands
);
4010 static DEFINE_MUTEX(ftrace_cmd_mutex
);
4013 * Currently we only register ftrace commands from __init, so mark this
4016 __init
int register_ftrace_command(struct ftrace_func_command
*cmd
)
4018 struct ftrace_func_command
*p
;
4021 mutex_lock(&ftrace_cmd_mutex
);
4022 list_for_each_entry(p
, &ftrace_commands
, list
) {
4023 if (strcmp(cmd
->name
, p
->name
) == 0) {
4028 list_add(&cmd
->list
, &ftrace_commands
);
4030 mutex_unlock(&ftrace_cmd_mutex
);
4036 * Currently we only unregister ftrace commands from __init, so mark
4039 __init
int unregister_ftrace_command(struct ftrace_func_command
*cmd
)
4041 struct ftrace_func_command
*p
, *n
;
4044 mutex_lock(&ftrace_cmd_mutex
);
4045 list_for_each_entry_safe(p
, n
, &ftrace_commands
, list
) {
4046 if (strcmp(cmd
->name
, p
->name
) == 0) {
4048 list_del_init(&p
->list
);
4053 mutex_unlock(&ftrace_cmd_mutex
);
4058 static int ftrace_process_regex(struct ftrace_hash
*hash
,
4059 char *buff
, int len
, int enable
)
4061 char *func
, *command
, *next
= buff
;
4062 struct ftrace_func_command
*p
;
4065 func
= strsep(&next
, ":");
4068 ret
= ftrace_match_records(hash
, func
, len
);
4078 command
= strsep(&next
, ":");
4080 mutex_lock(&ftrace_cmd_mutex
);
4081 list_for_each_entry(p
, &ftrace_commands
, list
) {
4082 if (strcmp(p
->name
, command
) == 0) {
4083 ret
= p
->func(hash
, func
, command
, next
, enable
);
4088 mutex_unlock(&ftrace_cmd_mutex
);
4094 ftrace_regex_write(struct file
*file
, const char __user
*ubuf
,
4095 size_t cnt
, loff_t
*ppos
, int enable
)
4097 struct ftrace_iterator
*iter
;
4098 struct trace_parser
*parser
;
4104 if (file
->f_mode
& FMODE_READ
) {
4105 struct seq_file
*m
= file
->private_data
;
4108 iter
= file
->private_data
;
4110 if (unlikely(ftrace_disabled
))
4113 /* iter->hash is a local copy, so we don't need regex_lock */
4115 parser
= &iter
->parser
;
4116 read
= trace_get_user(parser
, ubuf
, cnt
, ppos
);
4118 if (read
>= 0 && trace_parser_loaded(parser
) &&
4119 !trace_parser_cont(parser
)) {
4120 ret
= ftrace_process_regex(iter
->hash
, parser
->buffer
,
4121 parser
->idx
, enable
);
4122 trace_parser_clear(parser
);
4133 ftrace_filter_write(struct file
*file
, const char __user
*ubuf
,
4134 size_t cnt
, loff_t
*ppos
)
4136 return ftrace_regex_write(file
, ubuf
, cnt
, ppos
, 1);
4140 ftrace_notrace_write(struct file
*file
, const char __user
*ubuf
,
4141 size_t cnt
, loff_t
*ppos
)
4143 return ftrace_regex_write(file
, ubuf
, cnt
, ppos
, 0);
4147 ftrace_match_addr(struct ftrace_hash
*hash
, unsigned long ip
, int remove
)
4149 struct ftrace_func_entry
*entry
;
4151 if (!ftrace_location(ip
))
4155 entry
= ftrace_lookup_ip(hash
, ip
);
4158 free_hash_entry(hash
, entry
);
4162 return add_hash_entry(hash
, ip
);
4165 static void ftrace_ops_update_code(struct ftrace_ops
*ops
,
4166 struct ftrace_ops_hash
*old_hash
)
4168 struct ftrace_ops
*op
;
4170 if (!ftrace_enabled
)
4173 if (ops
->flags
& FTRACE_OPS_FL_ENABLED
) {
4174 ftrace_run_modify_code(ops
, FTRACE_UPDATE_CALLS
, old_hash
);
4179 * If this is the shared global_ops filter, then we need to
4180 * check if there is another ops that shares it, is enabled.
4181 * If so, we still need to run the modify code.
4183 if (ops
->func_hash
!= &global_ops
.local_hash
)
4186 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
4187 if (op
->func_hash
== &global_ops
.local_hash
&&
4188 op
->flags
& FTRACE_OPS_FL_ENABLED
) {
4189 ftrace_run_modify_code(op
, FTRACE_UPDATE_CALLS
, old_hash
);
4190 /* Only need to do this once */
4193 } while_for_each_ftrace_op(op
);
4197 ftrace_set_hash(struct ftrace_ops
*ops
, unsigned char *buf
, int len
,
4198 unsigned long ip
, int remove
, int reset
, int enable
)
4200 struct ftrace_hash
**orig_hash
;
4201 struct ftrace_ops_hash old_hash_ops
;
4202 struct ftrace_hash
*old_hash
;
4203 struct ftrace_hash
*hash
;
4206 if (unlikely(ftrace_disabled
))
4209 mutex_lock(&ops
->func_hash
->regex_lock
);
4212 orig_hash
= &ops
->func_hash
->filter_hash
;
4214 orig_hash
= &ops
->func_hash
->notrace_hash
;
4217 hash
= alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
);
4219 hash
= alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
, *orig_hash
);
4223 goto out_regex_unlock
;
4226 if (buf
&& !ftrace_match_records(hash
, buf
, len
)) {
4228 goto out_regex_unlock
;
4231 ret
= ftrace_match_addr(hash
, ip
, remove
);
4233 goto out_regex_unlock
;
4236 mutex_lock(&ftrace_lock
);
4237 old_hash
= *orig_hash
;
4238 old_hash_ops
.filter_hash
= ops
->func_hash
->filter_hash
;
4239 old_hash_ops
.notrace_hash
= ops
->func_hash
->notrace_hash
;
4240 ret
= ftrace_hash_move(ops
, enable
, orig_hash
, hash
);
4242 ftrace_ops_update_code(ops
, &old_hash_ops
);
4243 free_ftrace_hash_rcu(old_hash
);
4245 mutex_unlock(&ftrace_lock
);
4248 mutex_unlock(&ops
->func_hash
->regex_lock
);
4250 free_ftrace_hash(hash
);
4255 ftrace_set_addr(struct ftrace_ops
*ops
, unsigned long ip
, int remove
,
4256 int reset
, int enable
)
4258 return ftrace_set_hash(ops
, 0, 0, ip
, remove
, reset
, enable
);
4262 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
4263 * @ops - the ops to set the filter with
4264 * @ip - the address to add to or remove from the filter.
4265 * @remove - non zero to remove the ip from the filter
4266 * @reset - non zero to reset all filters before applying this filter.
4268 * Filters denote which functions should be enabled when tracing is enabled
4269 * If @ip is NULL, it failes to update filter.
4271 int ftrace_set_filter_ip(struct ftrace_ops
*ops
, unsigned long ip
,
4272 int remove
, int reset
)
4274 ftrace_ops_init(ops
);
4275 return ftrace_set_addr(ops
, ip
, remove
, reset
, 1);
4277 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip
);
4280 * ftrace_ops_set_global_filter - setup ops to use global filters
4281 * @ops - the ops which will use the global filters
4283 * ftrace users who need global function trace filtering should call this.
4284 * It can set the global filter only if ops were not initialized before.
4286 void ftrace_ops_set_global_filter(struct ftrace_ops
*ops
)
4288 if (ops
->flags
& FTRACE_OPS_FL_INITIALIZED
)
4291 ftrace_ops_init(ops
);
4292 ops
->func_hash
= &global_ops
.local_hash
;
4294 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter
);
4297 ftrace_set_regex(struct ftrace_ops
*ops
, unsigned char *buf
, int len
,
4298 int reset
, int enable
)
4300 return ftrace_set_hash(ops
, buf
, len
, 0, 0, reset
, enable
);
4304 * ftrace_set_filter - set a function to filter on in ftrace
4305 * @ops - the ops to set the filter with
4306 * @buf - the string that holds the function filter text.
4307 * @len - the length of the string.
4308 * @reset - non zero to reset all filters before applying this filter.
4310 * Filters denote which functions should be enabled when tracing is enabled.
4311 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4313 int ftrace_set_filter(struct ftrace_ops
*ops
, unsigned char *buf
,
4316 ftrace_ops_init(ops
);
4317 return ftrace_set_regex(ops
, buf
, len
, reset
, 1);
4319 EXPORT_SYMBOL_GPL(ftrace_set_filter
);
4322 * ftrace_set_notrace - set a function to not trace in ftrace
4323 * @ops - the ops to set the notrace filter with
4324 * @buf - the string that holds the function notrace text.
4325 * @len - the length of the string.
4326 * @reset - non zero to reset all filters before applying this filter.
4328 * Notrace Filters denote which functions should not be enabled when tracing
4329 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4332 int ftrace_set_notrace(struct ftrace_ops
*ops
, unsigned char *buf
,
4335 ftrace_ops_init(ops
);
4336 return ftrace_set_regex(ops
, buf
, len
, reset
, 0);
4338 EXPORT_SYMBOL_GPL(ftrace_set_notrace
);
4340 * ftrace_set_global_filter - set a function to filter on with global tracers
4341 * @buf - the string that holds the function filter text.
4342 * @len - the length of the string.
4343 * @reset - non zero to reset all filters before applying this filter.
4345 * Filters denote which functions should be enabled when tracing is enabled.
4346 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4348 void ftrace_set_global_filter(unsigned char *buf
, int len
, int reset
)
4350 ftrace_set_regex(&global_ops
, buf
, len
, reset
, 1);
4352 EXPORT_SYMBOL_GPL(ftrace_set_global_filter
);
4355 * ftrace_set_global_notrace - set a function to not trace with global tracers
4356 * @buf - the string that holds the function notrace text.
4357 * @len - the length of the string.
4358 * @reset - non zero to reset all filters before applying this filter.
4360 * Notrace Filters denote which functions should not be enabled when tracing
4361 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4364 void ftrace_set_global_notrace(unsigned char *buf
, int len
, int reset
)
4366 ftrace_set_regex(&global_ops
, buf
, len
, reset
, 0);
4368 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace
);
4371 * command line interface to allow users to set filters on boot up.
4373 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
4374 static char ftrace_notrace_buf
[FTRACE_FILTER_SIZE
] __initdata
;
4375 static char ftrace_filter_buf
[FTRACE_FILTER_SIZE
] __initdata
;
4377 /* Used by function selftest to not test if filter is set */
4378 bool ftrace_filter_param __initdata
;
4380 static int __init
set_ftrace_notrace(char *str
)
4382 ftrace_filter_param
= true;
4383 strlcpy(ftrace_notrace_buf
, str
, FTRACE_FILTER_SIZE
);
4386 __setup("ftrace_notrace=", set_ftrace_notrace
);
4388 static int __init
set_ftrace_filter(char *str
)
4390 ftrace_filter_param
= true;
4391 strlcpy(ftrace_filter_buf
, str
, FTRACE_FILTER_SIZE
);
4394 __setup("ftrace_filter=", set_ftrace_filter
);
4396 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4397 static char ftrace_graph_buf
[FTRACE_FILTER_SIZE
] __initdata
;
4398 static char ftrace_graph_notrace_buf
[FTRACE_FILTER_SIZE
] __initdata
;
4399 static int ftrace_graph_set_hash(struct ftrace_hash
*hash
, char *buffer
);
4401 static unsigned long save_global_trampoline
;
4402 static unsigned long save_global_flags
;
4404 static int __init
set_graph_function(char *str
)
4406 strlcpy(ftrace_graph_buf
, str
, FTRACE_FILTER_SIZE
);
4409 __setup("ftrace_graph_filter=", set_graph_function
);
4411 static int __init
set_graph_notrace_function(char *str
)
4413 strlcpy(ftrace_graph_notrace_buf
, str
, FTRACE_FILTER_SIZE
);
4416 __setup("ftrace_graph_notrace=", set_graph_notrace_function
);
4418 static void __init
set_ftrace_early_graph(char *buf
, int enable
)
4422 struct ftrace_hash
*hash
;
4425 hash
= ftrace_graph_hash
;
4427 hash
= ftrace_graph_notrace_hash
;
4430 func
= strsep(&buf
, ",");
4431 /* we allow only one expression at a time */
4432 ret
= ftrace_graph_set_hash(hash
, func
);
4434 printk(KERN_DEBUG
"ftrace: function %s not "
4435 "traceable\n", func
);
4438 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4441 ftrace_set_early_filter(struct ftrace_ops
*ops
, char *buf
, int enable
)
4445 ftrace_ops_init(ops
);
4448 func
= strsep(&buf
, ",");
4449 ftrace_set_regex(ops
, func
, strlen(func
), 0, enable
);
4453 static void __init
set_ftrace_early_filters(void)
4455 if (ftrace_filter_buf
[0])
4456 ftrace_set_early_filter(&global_ops
, ftrace_filter_buf
, 1);
4457 if (ftrace_notrace_buf
[0])
4458 ftrace_set_early_filter(&global_ops
, ftrace_notrace_buf
, 0);
4459 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4460 if (ftrace_graph_buf
[0])
4461 set_ftrace_early_graph(ftrace_graph_buf
, 1);
4462 if (ftrace_graph_notrace_buf
[0])
4463 set_ftrace_early_graph(ftrace_graph_notrace_buf
, 0);
4464 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4467 int ftrace_regex_release(struct inode
*inode
, struct file
*file
)
4469 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
4470 struct ftrace_ops_hash old_hash_ops
;
4471 struct ftrace_iterator
*iter
;
4472 struct ftrace_hash
**orig_hash
;
4473 struct ftrace_hash
*old_hash
;
4474 struct trace_parser
*parser
;
4478 if (file
->f_mode
& FMODE_READ
) {
4480 seq_release(inode
, file
);
4482 iter
= file
->private_data
;
4484 parser
= &iter
->parser
;
4485 if (trace_parser_loaded(parser
)) {
4486 parser
->buffer
[parser
->idx
] = 0;
4487 ftrace_match_records(iter
->hash
, parser
->buffer
, parser
->idx
);
4490 trace_parser_put(parser
);
4492 mutex_lock(&iter
->ops
->func_hash
->regex_lock
);
4494 if (file
->f_mode
& FMODE_WRITE
) {
4495 filter_hash
= !!(iter
->flags
& FTRACE_ITER_FILTER
);
4498 orig_hash
= &iter
->ops
->func_hash
->filter_hash
;
4500 orig_hash
= &iter
->ops
->func_hash
->notrace_hash
;
4502 mutex_lock(&ftrace_lock
);
4503 old_hash
= *orig_hash
;
4504 old_hash_ops
.filter_hash
= iter
->ops
->func_hash
->filter_hash
;
4505 old_hash_ops
.notrace_hash
= iter
->ops
->func_hash
->notrace_hash
;
4506 ret
= ftrace_hash_move(iter
->ops
, filter_hash
,
4507 orig_hash
, iter
->hash
);
4509 ftrace_ops_update_code(iter
->ops
, &old_hash_ops
);
4510 free_ftrace_hash_rcu(old_hash
);
4512 mutex_unlock(&ftrace_lock
);
4515 mutex_unlock(&iter
->ops
->func_hash
->regex_lock
);
4516 free_ftrace_hash(iter
->hash
);
4522 static const struct file_operations ftrace_avail_fops
= {
4523 .open
= ftrace_avail_open
,
4525 .llseek
= seq_lseek
,
4526 .release
= seq_release_private
,
4529 static const struct file_operations ftrace_enabled_fops
= {
4530 .open
= ftrace_enabled_open
,
4532 .llseek
= seq_lseek
,
4533 .release
= seq_release_private
,
4536 static const struct file_operations ftrace_filter_fops
= {
4537 .open
= ftrace_filter_open
,
4539 .write
= ftrace_filter_write
,
4540 .llseek
= tracing_lseek
,
4541 .release
= ftrace_regex_release
,
4544 static const struct file_operations ftrace_notrace_fops
= {
4545 .open
= ftrace_notrace_open
,
4547 .write
= ftrace_notrace_write
,
4548 .llseek
= tracing_lseek
,
4549 .release
= ftrace_regex_release
,
4552 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4554 static DEFINE_MUTEX(graph_lock
);
4556 struct ftrace_hash
*ftrace_graph_hash
= EMPTY_HASH
;
4557 struct ftrace_hash
*ftrace_graph_notrace_hash
= EMPTY_HASH
;
4559 enum graph_filter_type
{
4560 GRAPH_FILTER_NOTRACE
= 0,
4561 GRAPH_FILTER_FUNCTION
,
4564 #define FTRACE_GRAPH_EMPTY ((void *)1)
4566 struct ftrace_graph_data
{
4567 struct ftrace_hash
*hash
;
4568 struct ftrace_func_entry
*entry
;
4569 int idx
; /* for hash table iteration */
4570 enum graph_filter_type type
;
4571 struct ftrace_hash
*new_hash
;
4572 const struct seq_operations
*seq_ops
;
4576 __g_next(struct seq_file
*m
, loff_t
*pos
)
4578 struct ftrace_graph_data
*fgd
= m
->private;
4579 struct ftrace_func_entry
*entry
= fgd
->entry
;
4580 struct hlist_head
*head
;
4581 int i
, idx
= fgd
->idx
;
4583 if (*pos
>= fgd
->hash
->count
)
4587 hlist_for_each_entry_continue(entry
, hlist
) {
4595 for (i
= idx
; i
< 1 << fgd
->hash
->size_bits
; i
++) {
4596 head
= &fgd
->hash
->buckets
[i
];
4597 hlist_for_each_entry(entry
, head
, hlist
) {
4607 g_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
4610 return __g_next(m
, pos
);
4613 static void *g_start(struct seq_file
*m
, loff_t
*pos
)
4615 struct ftrace_graph_data
*fgd
= m
->private;
4617 mutex_lock(&graph_lock
);
4619 if (fgd
->type
== GRAPH_FILTER_FUNCTION
)
4620 fgd
->hash
= rcu_dereference_protected(ftrace_graph_hash
,
4621 lockdep_is_held(&graph_lock
));
4623 fgd
->hash
= rcu_dereference_protected(ftrace_graph_notrace_hash
,
4624 lockdep_is_held(&graph_lock
));
4626 /* Nothing, tell g_show to print all functions are enabled */
4627 if (ftrace_hash_empty(fgd
->hash
) && !*pos
)
4628 return FTRACE_GRAPH_EMPTY
;
4632 return __g_next(m
, pos
);
4635 static void g_stop(struct seq_file
*m
, void *p
)
4637 mutex_unlock(&graph_lock
);
4640 static int g_show(struct seq_file
*m
, void *v
)
4642 struct ftrace_func_entry
*entry
= v
;
4647 if (entry
== FTRACE_GRAPH_EMPTY
) {
4648 struct ftrace_graph_data
*fgd
= m
->private;
4650 if (fgd
->type
== GRAPH_FILTER_FUNCTION
)
4651 seq_puts(m
, "#### all functions enabled ####\n");
4653 seq_puts(m
, "#### no functions disabled ####\n");
4657 seq_printf(m
, "%ps\n", (void *)entry
->ip
);
4662 static const struct seq_operations ftrace_graph_seq_ops
= {
4670 __ftrace_graph_open(struct inode
*inode
, struct file
*file
,
4671 struct ftrace_graph_data
*fgd
)
4674 struct ftrace_hash
*new_hash
= NULL
;
4676 if (file
->f_mode
& FMODE_WRITE
) {
4677 const int size_bits
= FTRACE_HASH_DEFAULT_BITS
;
4679 if (file
->f_flags
& O_TRUNC
)
4680 new_hash
= alloc_ftrace_hash(size_bits
);
4682 new_hash
= alloc_and_copy_ftrace_hash(size_bits
,
4690 if (file
->f_mode
& FMODE_READ
) {
4691 ret
= seq_open(file
, &ftrace_graph_seq_ops
);
4693 struct seq_file
*m
= file
->private_data
;
4697 free_ftrace_hash(new_hash
);
4701 file
->private_data
= fgd
;
4704 fgd
->new_hash
= new_hash
;
4707 * All uses of fgd->hash must be taken with the graph_lock
4708 * held. The graph_lock is going to be released, so force
4709 * fgd->hash to be reinitialized when it is taken again.
4717 ftrace_graph_open(struct inode
*inode
, struct file
*file
)
4719 struct ftrace_graph_data
*fgd
;
4722 if (unlikely(ftrace_disabled
))
4725 fgd
= kmalloc(sizeof(*fgd
), GFP_KERNEL
);
4729 mutex_lock(&graph_lock
);
4731 fgd
->hash
= rcu_dereference_protected(ftrace_graph_hash
,
4732 lockdep_is_held(&graph_lock
));
4733 fgd
->type
= GRAPH_FILTER_FUNCTION
;
4734 fgd
->seq_ops
= &ftrace_graph_seq_ops
;
4736 ret
= __ftrace_graph_open(inode
, file
, fgd
);
4740 mutex_unlock(&graph_lock
);
4745 ftrace_graph_notrace_open(struct inode
*inode
, struct file
*file
)
4747 struct ftrace_graph_data
*fgd
;
4750 if (unlikely(ftrace_disabled
))
4753 fgd
= kmalloc(sizeof(*fgd
), GFP_KERNEL
);
4757 mutex_lock(&graph_lock
);
4759 fgd
->hash
= rcu_dereference_protected(ftrace_graph_notrace_hash
,
4760 lockdep_is_held(&graph_lock
));
4761 fgd
->type
= GRAPH_FILTER_NOTRACE
;
4762 fgd
->seq_ops
= &ftrace_graph_seq_ops
;
4764 ret
= __ftrace_graph_open(inode
, file
, fgd
);
4768 mutex_unlock(&graph_lock
);
4773 ftrace_graph_release(struct inode
*inode
, struct file
*file
)
4775 struct ftrace_graph_data
*fgd
;
4777 if (file
->f_mode
& FMODE_READ
) {
4778 struct seq_file
*m
= file
->private_data
;
4781 seq_release(inode
, file
);
4783 fgd
= file
->private_data
;
4786 kfree(fgd
->new_hash
);
4793 ftrace_graph_set_hash(struct ftrace_hash
*hash
, char *buffer
)
4795 struct ftrace_glob func_g
;
4796 struct dyn_ftrace
*rec
;
4797 struct ftrace_page
*pg
;
4798 struct ftrace_func_entry
*entry
;
4803 func_g
.type
= filter_parse_regex(buffer
, strlen(buffer
),
4804 &func_g
.search
, ¬);
4806 func_g
.len
= strlen(func_g
.search
);
4808 mutex_lock(&ftrace_lock
);
4810 if (unlikely(ftrace_disabled
)) {
4811 mutex_unlock(&ftrace_lock
);
4815 do_for_each_ftrace_rec(pg
, rec
) {
4817 if (rec
->flags
& FTRACE_FL_DISABLED
)
4820 if (ftrace_match_record(rec
, &func_g
, NULL
, 0)) {
4821 entry
= ftrace_lookup_ip(hash
, rec
->ip
);
4828 if (add_hash_entry(hash
, rec
->ip
) < 0)
4832 free_hash_entry(hash
, entry
);
4837 } while_for_each_ftrace_rec();
4839 mutex_unlock(&ftrace_lock
);
4848 ftrace_graph_write(struct file
*file
, const char __user
*ubuf
,
4849 size_t cnt
, loff_t
*ppos
)
4851 struct trace_parser parser
;
4852 ssize_t read
, ret
= 0;
4853 struct ftrace_graph_data
*fgd
= file
->private_data
;
4854 struct ftrace_hash
*old_hash
, *new_hash
;
4859 if (trace_parser_get_init(&parser
, FTRACE_BUFF_MAX
))
4862 /* Read mode uses seq functions */
4863 if (file
->f_mode
& FMODE_READ
) {
4864 struct seq_file
*m
= file
->private_data
;
4868 read
= trace_get_user(&parser
, ubuf
, cnt
, ppos
);
4870 if (read
>= 0 && trace_parser_loaded((&parser
))) {
4871 parser
.buffer
[parser
.idx
] = 0;
4873 mutex_lock(&graph_lock
);
4875 /* we allow only one expression at a time */
4876 ret
= ftrace_graph_set_hash(fgd
->new_hash
,
4879 new_hash
= __ftrace_hash_move(fgd
->new_hash
);
4883 if (fgd
->type
== GRAPH_FILTER_FUNCTION
) {
4884 old_hash
= rcu_dereference_protected(ftrace_graph_hash
,
4885 lockdep_is_held(&graph_lock
));
4886 rcu_assign_pointer(ftrace_graph_hash
, new_hash
);
4888 old_hash
= rcu_dereference_protected(ftrace_graph_notrace_hash
,
4889 lockdep_is_held(&graph_lock
));
4890 rcu_assign_pointer(ftrace_graph_notrace_hash
, new_hash
);
4893 mutex_unlock(&graph_lock
);
4895 /* Wait till all users are no longer using the old hash */
4896 synchronize_sched();
4898 free_ftrace_hash(old_hash
);
4904 trace_parser_put(&parser
);
4909 static const struct file_operations ftrace_graph_fops
= {
4910 .open
= ftrace_graph_open
,
4912 .write
= ftrace_graph_write
,
4913 .llseek
= tracing_lseek
,
4914 .release
= ftrace_graph_release
,
4917 static const struct file_operations ftrace_graph_notrace_fops
= {
4918 .open
= ftrace_graph_notrace_open
,
4920 .write
= ftrace_graph_write
,
4921 .llseek
= tracing_lseek
,
4922 .release
= ftrace_graph_release
,
4924 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4926 void ftrace_create_filter_files(struct ftrace_ops
*ops
,
4927 struct dentry
*parent
)
4930 trace_create_file("set_ftrace_filter", 0644, parent
,
4931 ops
, &ftrace_filter_fops
);
4933 trace_create_file("set_ftrace_notrace", 0644, parent
,
4934 ops
, &ftrace_notrace_fops
);
4938 * The name "destroy_filter_files" is really a misnomer. Although
4939 * in the future, it may actualy delete the files, but this is
4940 * really intended to make sure the ops passed in are disabled
4941 * and that when this function returns, the caller is free to
4944 * The "destroy" name is only to match the "create" name that this
4945 * should be paired with.
4947 void ftrace_destroy_filter_files(struct ftrace_ops
*ops
)
4949 mutex_lock(&ftrace_lock
);
4950 if (ops
->flags
& FTRACE_OPS_FL_ENABLED
)
4951 ftrace_shutdown(ops
, 0);
4952 ops
->flags
|= FTRACE_OPS_FL_DELETED
;
4953 mutex_unlock(&ftrace_lock
);
4956 static __init
int ftrace_init_dyn_tracefs(struct dentry
*d_tracer
)
4959 trace_create_file("available_filter_functions", 0444,
4960 d_tracer
, NULL
, &ftrace_avail_fops
);
4962 trace_create_file("enabled_functions", 0444,
4963 d_tracer
, NULL
, &ftrace_enabled_fops
);
4965 ftrace_create_filter_files(&global_ops
, d_tracer
);
4967 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4968 trace_create_file("set_graph_function", 0444, d_tracer
,
4970 &ftrace_graph_fops
);
4971 trace_create_file("set_graph_notrace", 0444, d_tracer
,
4973 &ftrace_graph_notrace_fops
);
4974 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4979 static int ftrace_cmp_ips(const void *a
, const void *b
)
4981 const unsigned long *ipa
= a
;
4982 const unsigned long *ipb
= b
;
4991 static int ftrace_process_locs(struct module
*mod
,
4992 unsigned long *start
,
4995 struct ftrace_page
*start_pg
;
4996 struct ftrace_page
*pg
;
4997 struct dyn_ftrace
*rec
;
4998 unsigned long count
;
5001 unsigned long flags
= 0; /* Shut up gcc */
5004 count
= end
- start
;
5009 sort(start
, count
, sizeof(*start
),
5010 ftrace_cmp_ips
, NULL
);
5012 start_pg
= ftrace_allocate_pages(count
);
5016 mutex_lock(&ftrace_lock
);
5019 * Core and each module needs their own pages, as
5020 * modules will free them when they are removed.
5021 * Force a new page to be allocated for modules.
5024 WARN_ON(ftrace_pages
|| ftrace_pages_start
);
5025 /* First initialization */
5026 ftrace_pages
= ftrace_pages_start
= start_pg
;
5031 if (WARN_ON(ftrace_pages
->next
)) {
5032 /* Hmm, we have free pages? */
5033 while (ftrace_pages
->next
)
5034 ftrace_pages
= ftrace_pages
->next
;
5037 ftrace_pages
->next
= start_pg
;
5043 addr
= ftrace_call_adjust(*p
++);
5045 * Some architecture linkers will pad between
5046 * the different mcount_loc sections of different
5047 * object files to satisfy alignments.
5048 * Skip any NULL pointers.
5053 if (pg
->index
== pg
->size
) {
5054 /* We should have allocated enough */
5055 if (WARN_ON(!pg
->next
))
5060 rec
= &pg
->records
[pg
->index
++];
5064 /* We should have used all pages */
5067 /* Assign the last page to ftrace_pages */
5071 * We only need to disable interrupts on start up
5072 * because we are modifying code that an interrupt
5073 * may execute, and the modification is not atomic.
5074 * But for modules, nothing runs the code we modify
5075 * until we are finished with it, and there's no
5076 * reason to cause large interrupt latencies while we do it.
5079 local_irq_save(flags
);
5080 ftrace_update_code(mod
, start_pg
);
5082 local_irq_restore(flags
);
5085 mutex_unlock(&ftrace_lock
);
5090 #ifdef CONFIG_MODULES
5092 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
5094 static int referenced_filters(struct dyn_ftrace
*rec
)
5096 struct ftrace_ops
*ops
;
5099 for (ops
= ftrace_ops_list
; ops
!= &ftrace_list_end
; ops
= ops
->next
) {
5100 if (ops_references_rec(ops
, rec
))
5107 void ftrace_release_mod(struct module
*mod
)
5109 struct dyn_ftrace
*rec
;
5110 struct ftrace_page
**last_pg
;
5111 struct ftrace_page
*pg
;
5114 mutex_lock(&ftrace_lock
);
5116 if (ftrace_disabled
)
5120 * Each module has its own ftrace_pages, remove
5121 * them from the list.
5123 last_pg
= &ftrace_pages_start
;
5124 for (pg
= ftrace_pages_start
; pg
; pg
= *last_pg
) {
5125 rec
= &pg
->records
[0];
5126 if (within_module_core(rec
->ip
, mod
)) {
5128 * As core pages are first, the first
5129 * page should never be a module page.
5131 if (WARN_ON(pg
== ftrace_pages_start
))
5134 /* Check if we are deleting the last page */
5135 if (pg
== ftrace_pages
)
5136 ftrace_pages
= next_to_ftrace_page(last_pg
);
5138 *last_pg
= pg
->next
;
5139 order
= get_count_order(pg
->size
/ ENTRIES_PER_PAGE
);
5140 free_pages((unsigned long)pg
->records
, order
);
5143 last_pg
= &pg
->next
;
5146 mutex_unlock(&ftrace_lock
);
5149 void ftrace_module_enable(struct module
*mod
)
5151 struct dyn_ftrace
*rec
;
5152 struct ftrace_page
*pg
;
5154 mutex_lock(&ftrace_lock
);
5156 if (ftrace_disabled
)
5160 * If the tracing is enabled, go ahead and enable the record.
5162 * The reason not to enable the record immediatelly is the
5163 * inherent check of ftrace_make_nop/ftrace_make_call for
5164 * correct previous instructions. Making first the NOP
5165 * conversion puts the module to the correct state, thus
5166 * passing the ftrace_make_call check.
5168 * We also delay this to after the module code already set the
5169 * text to read-only, as we now need to set it back to read-write
5170 * so that we can modify the text.
5172 if (ftrace_start_up
)
5173 ftrace_arch_code_modify_prepare();
5175 do_for_each_ftrace_rec(pg
, rec
) {
5178 * do_for_each_ftrace_rec() is a double loop.
5179 * module text shares the pg. If a record is
5180 * not part of this module, then skip this pg,
5181 * which the "break" will do.
5183 if (!within_module_core(rec
->ip
, mod
))
5189 * When adding a module, we need to check if tracers are
5190 * currently enabled and if they are, and can trace this record,
5191 * we need to enable the module functions as well as update the
5192 * reference counts for those function records.
5194 if (ftrace_start_up
)
5195 cnt
+= referenced_filters(rec
);
5197 /* This clears FTRACE_FL_DISABLED */
5200 if (ftrace_start_up
&& cnt
) {
5201 int failed
= __ftrace_replace_code(rec
, 1);
5203 ftrace_bug(failed
, rec
);
5208 } while_for_each_ftrace_rec();
5211 if (ftrace_start_up
)
5212 ftrace_arch_code_modify_post_process();
5215 mutex_unlock(&ftrace_lock
);
5218 void ftrace_module_init(struct module
*mod
)
5220 if (ftrace_disabled
|| !mod
->num_ftrace_callsites
)
5223 ftrace_process_locs(mod
, mod
->ftrace_callsites
,
5224 mod
->ftrace_callsites
+ mod
->num_ftrace_callsites
);
5226 #endif /* CONFIG_MODULES */
5228 void __init
ftrace_init(void)
5230 extern unsigned long __start_mcount_loc
[];
5231 extern unsigned long __stop_mcount_loc
[];
5232 unsigned long count
, flags
;
5235 local_irq_save(flags
);
5236 ret
= ftrace_dyn_arch_init();
5237 local_irq_restore(flags
);
5241 count
= __stop_mcount_loc
- __start_mcount_loc
;
5243 pr_info("ftrace: No functions to be traced?\n");
5247 pr_info("ftrace: allocating %ld entries in %ld pages\n",
5248 count
, count
/ ENTRIES_PER_PAGE
+ 1);
5250 last_ftrace_enabled
= ftrace_enabled
= 1;
5252 ret
= ftrace_process_locs(NULL
,
5256 set_ftrace_early_filters();
5260 ftrace_disabled
= 1;
5263 /* Do nothing if arch does not support this */
5264 void __weak
arch_ftrace_update_trampoline(struct ftrace_ops
*ops
)
5268 static void ftrace_update_trampoline(struct ftrace_ops
*ops
)
5272 * Currently there's no safe way to free a trampoline when the kernel
5273 * is configured with PREEMPT. That is because a task could be preempted
5274 * when it jumped to the trampoline, it may be preempted for a long time
5275 * depending on the system load, and currently there's no way to know
5276 * when it will be off the trampoline. If the trampoline is freed
5277 * too early, when the task runs again, it will be executing on freed
5280 #ifdef CONFIG_PREEMPT
5281 /* Currently, only non dynamic ops can have a trampoline */
5282 if (ops
->flags
& FTRACE_OPS_FL_DYNAMIC
)
5286 arch_ftrace_update_trampoline(ops
);
5291 static struct ftrace_ops global_ops
= {
5292 .func
= ftrace_stub
,
5293 .flags
= FTRACE_OPS_FL_RECURSION_SAFE
|
5294 FTRACE_OPS_FL_INITIALIZED
|
5298 static int __init
ftrace_nodyn_init(void)
5303 core_initcall(ftrace_nodyn_init
);
5305 static inline int ftrace_init_dyn_tracefs(struct dentry
*d_tracer
) { return 0; }
5306 static inline void ftrace_startup_enable(int command
) { }
5307 static inline void ftrace_startup_all(int command
) { }
5308 /* Keep as macros so we do not need to define the commands */
5309 # define ftrace_startup(ops, command) \
5311 int ___ret = __register_ftrace_function(ops); \
5313 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
5316 # define ftrace_shutdown(ops, command) \
5318 int ___ret = __unregister_ftrace_function(ops); \
5320 (ops)->flags &= ~FTRACE_OPS_FL_ENABLED; \
5324 # define ftrace_startup_sysctl() do { } while (0)
5325 # define ftrace_shutdown_sysctl() do { } while (0)
5328 ftrace_ops_test(struct ftrace_ops
*ops
, unsigned long ip
, void *regs
)
5333 static void ftrace_update_trampoline(struct ftrace_ops
*ops
)
5337 #endif /* CONFIG_DYNAMIC_FTRACE */
5339 __init
void ftrace_init_global_array_ops(struct trace_array
*tr
)
5341 tr
->ops
= &global_ops
;
5342 tr
->ops
->private = tr
;
5345 void ftrace_init_array_ops(struct trace_array
*tr
, ftrace_func_t func
)
5347 /* If we filter on pids, update to use the pid function */
5348 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
) {
5349 if (WARN_ON(tr
->ops
->func
!= ftrace_stub
))
5350 printk("ftrace ops had %pS for function\n",
5353 tr
->ops
->func
= func
;
5354 tr
->ops
->private = tr
;
5357 void ftrace_reset_array_ops(struct trace_array
*tr
)
5359 tr
->ops
->func
= ftrace_stub
;
5363 __ftrace_ops_list_func(unsigned long ip
, unsigned long parent_ip
,
5364 struct ftrace_ops
*ignored
, struct pt_regs
*regs
)
5366 struct ftrace_ops
*op
;
5369 bit
= trace_test_and_set_recursion(TRACE_LIST_START
, TRACE_LIST_MAX
);
5374 * Some of the ops may be dynamically allocated,
5375 * they must be freed after a synchronize_sched().
5377 preempt_disable_notrace();
5379 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
5381 * Check the following for each ops before calling their func:
5382 * if RCU flag is set, then rcu_is_watching() must be true
5383 * if PER_CPU is set, then ftrace_function_local_disable()
5385 * Otherwise test if the ip matches the ops filter
5387 * If any of the above fails then the op->func() is not executed.
5389 if ((!(op
->flags
& FTRACE_OPS_FL_RCU
) || rcu_is_watching()) &&
5390 (!(op
->flags
& FTRACE_OPS_FL_PER_CPU
) ||
5391 !ftrace_function_local_disabled(op
)) &&
5392 ftrace_ops_test(op
, ip
, regs
)) {
5394 if (FTRACE_WARN_ON(!op
->func
)) {
5395 pr_warn("op=%p %pS\n", op
, op
);
5398 op
->func(ip
, parent_ip
, op
, regs
);
5400 } while_for_each_ftrace_op(op
);
5402 preempt_enable_notrace();
5403 trace_clear_recursion(bit
);
5407 * Some archs only support passing ip and parent_ip. Even though
5408 * the list function ignores the op parameter, we do not want any
5409 * C side effects, where a function is called without the caller
5410 * sending a third parameter.
5411 * Archs are to support both the regs and ftrace_ops at the same time.
5412 * If they support ftrace_ops, it is assumed they support regs.
5413 * If call backs want to use regs, they must either check for regs
5414 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
5415 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
5416 * An architecture can pass partial regs with ftrace_ops and still
5417 * set the ARCH_SUPPORTS_FTRACE_OPS.
5419 #if ARCH_SUPPORTS_FTRACE_OPS
5420 static void ftrace_ops_list_func(unsigned long ip
, unsigned long parent_ip
,
5421 struct ftrace_ops
*op
, struct pt_regs
*regs
)
5423 __ftrace_ops_list_func(ip
, parent_ip
, NULL
, regs
);
5426 static void ftrace_ops_no_ops(unsigned long ip
, unsigned long parent_ip
)
5428 __ftrace_ops_list_func(ip
, parent_ip
, NULL
, NULL
);
5433 * If there's only one function registered but it does not support
5434 * recursion, needs RCU protection and/or requires per cpu handling, then
5435 * this function will be called by the mcount trampoline.
5437 static void ftrace_ops_assist_func(unsigned long ip
, unsigned long parent_ip
,
5438 struct ftrace_ops
*op
, struct pt_regs
*regs
)
5442 if ((op
->flags
& FTRACE_OPS_FL_RCU
) && !rcu_is_watching())
5445 bit
= trace_test_and_set_recursion(TRACE_LIST_START
, TRACE_LIST_MAX
);
5449 preempt_disable_notrace();
5451 if (!(op
->flags
& FTRACE_OPS_FL_PER_CPU
) ||
5452 !ftrace_function_local_disabled(op
)) {
5453 op
->func(ip
, parent_ip
, op
, regs
);
5456 preempt_enable_notrace();
5457 trace_clear_recursion(bit
);
5461 * ftrace_ops_get_func - get the function a trampoline should call
5462 * @ops: the ops to get the function for
5464 * Normally the mcount trampoline will call the ops->func, but there
5465 * are times that it should not. For example, if the ops does not
5466 * have its own recursion protection, then it should call the
5467 * ftrace_ops_recurs_func() instead.
5469 * Returns the function that the trampoline should call for @ops.
5471 ftrace_func_t
ftrace_ops_get_func(struct ftrace_ops
*ops
)
5474 * If the function does not handle recursion, needs to be RCU safe,
5475 * or does per cpu logic, then we need to call the assist handler.
5477 if (!(ops
->flags
& FTRACE_OPS_FL_RECURSION_SAFE
) ||
5478 ops
->flags
& (FTRACE_OPS_FL_RCU
| FTRACE_OPS_FL_PER_CPU
))
5479 return ftrace_ops_assist_func
;
5485 ftrace_filter_pid_sched_switch_probe(void *data
, bool preempt
,
5486 struct task_struct
*prev
, struct task_struct
*next
)
5488 struct trace_array
*tr
= data
;
5489 struct trace_pid_list
*pid_list
;
5491 pid_list
= rcu_dereference_sched(tr
->function_pids
);
5493 this_cpu_write(tr
->trace_buffer
.data
->ftrace_ignore_pid
,
5494 trace_ignore_this_task(pid_list
, next
));
5497 static void clear_ftrace_pids(struct trace_array
*tr
)
5499 struct trace_pid_list
*pid_list
;
5502 pid_list
= rcu_dereference_protected(tr
->function_pids
,
5503 lockdep_is_held(&ftrace_lock
));
5507 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe
, tr
);
5509 for_each_possible_cpu(cpu
)
5510 per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->ftrace_ignore_pid
= false;
5512 rcu_assign_pointer(tr
->function_pids
, NULL
);
5514 /* Wait till all users are no longer using pid filtering */
5515 synchronize_sched();
5517 trace_free_pid_list(pid_list
);
5520 static void ftrace_pid_reset(struct trace_array
*tr
)
5522 mutex_lock(&ftrace_lock
);
5523 clear_ftrace_pids(tr
);
5525 ftrace_update_pid_func();
5526 ftrace_startup_all(0);
5528 mutex_unlock(&ftrace_lock
);
5531 /* Greater than any max PID */
5532 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
5534 static void *fpid_start(struct seq_file
*m
, loff_t
*pos
)
5537 struct trace_pid_list
*pid_list
;
5538 struct trace_array
*tr
= m
->private;
5540 mutex_lock(&ftrace_lock
);
5541 rcu_read_lock_sched();
5543 pid_list
= rcu_dereference_sched(tr
->function_pids
);
5546 return !(*pos
) ? FTRACE_NO_PIDS
: NULL
;
5548 return trace_pid_start(pid_list
, pos
);
5551 static void *fpid_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
5553 struct trace_array
*tr
= m
->private;
5554 struct trace_pid_list
*pid_list
= rcu_dereference_sched(tr
->function_pids
);
5556 if (v
== FTRACE_NO_PIDS
)
5559 return trace_pid_next(pid_list
, v
, pos
);
5562 static void fpid_stop(struct seq_file
*m
, void *p
)
5565 rcu_read_unlock_sched();
5566 mutex_unlock(&ftrace_lock
);
5569 static int fpid_show(struct seq_file
*m
, void *v
)
5571 if (v
== FTRACE_NO_PIDS
) {
5572 seq_puts(m
, "no pid\n");
5576 return trace_pid_show(m
, v
);
5579 static const struct seq_operations ftrace_pid_sops
= {
5580 .start
= fpid_start
,
5587 ftrace_pid_open(struct inode
*inode
, struct file
*file
)
5589 struct trace_array
*tr
= inode
->i_private
;
5593 if (trace_array_get(tr
) < 0)
5596 if ((file
->f_mode
& FMODE_WRITE
) &&
5597 (file
->f_flags
& O_TRUNC
))
5598 ftrace_pid_reset(tr
);
5600 ret
= seq_open(file
, &ftrace_pid_sops
);
5602 trace_array_put(tr
);
5604 m
= file
->private_data
;
5605 /* copy tr over to seq ops */
5612 static void ignore_task_cpu(void *data
)
5614 struct trace_array
*tr
= data
;
5615 struct trace_pid_list
*pid_list
;
5618 * This function is called by on_each_cpu() while the
5619 * event_mutex is held.
5621 pid_list
= rcu_dereference_protected(tr
->function_pids
,
5622 mutex_is_locked(&ftrace_lock
));
5624 this_cpu_write(tr
->trace_buffer
.data
->ftrace_ignore_pid
,
5625 trace_ignore_this_task(pid_list
, current
));
5629 ftrace_pid_write(struct file
*filp
, const char __user
*ubuf
,
5630 size_t cnt
, loff_t
*ppos
)
5632 struct seq_file
*m
= filp
->private_data
;
5633 struct trace_array
*tr
= m
->private;
5634 struct trace_pid_list
*filtered_pids
= NULL
;
5635 struct trace_pid_list
*pid_list
;
5641 mutex_lock(&ftrace_lock
);
5643 filtered_pids
= rcu_dereference_protected(tr
->function_pids
,
5644 lockdep_is_held(&ftrace_lock
));
5646 ret
= trace_pid_write(filtered_pids
, &pid_list
, ubuf
, cnt
);
5650 rcu_assign_pointer(tr
->function_pids
, pid_list
);
5652 if (filtered_pids
) {
5653 synchronize_sched();
5654 trace_free_pid_list(filtered_pids
);
5655 } else if (pid_list
) {
5656 /* Register a probe to set whether to ignore the tracing of a task */
5657 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe
, tr
);
5661 * Ignoring of pids is done at task switch. But we have to
5662 * check for those tasks that are currently running.
5663 * Always do this in case a pid was appended or removed.
5665 on_each_cpu(ignore_task_cpu
, tr
, 1);
5667 ftrace_update_pid_func();
5668 ftrace_startup_all(0);
5670 mutex_unlock(&ftrace_lock
);
5679 ftrace_pid_release(struct inode
*inode
, struct file
*file
)
5681 struct trace_array
*tr
= inode
->i_private
;
5683 trace_array_put(tr
);
5685 return seq_release(inode
, file
);
5688 static const struct file_operations ftrace_pid_fops
= {
5689 .open
= ftrace_pid_open
,
5690 .write
= ftrace_pid_write
,
5692 .llseek
= tracing_lseek
,
5693 .release
= ftrace_pid_release
,
5696 void ftrace_init_tracefs(struct trace_array
*tr
, struct dentry
*d_tracer
)
5698 trace_create_file("set_ftrace_pid", 0644, d_tracer
,
5699 tr
, &ftrace_pid_fops
);
5702 void __init
ftrace_init_tracefs_toplevel(struct trace_array
*tr
,
5703 struct dentry
*d_tracer
)
5705 /* Only the top level directory has the dyn_tracefs and profile */
5706 WARN_ON(!(tr
->flags
& TRACE_ARRAY_FL_GLOBAL
));
5708 ftrace_init_dyn_tracefs(d_tracer
);
5709 ftrace_profile_tracefs(d_tracer
);
5713 * ftrace_kill - kill ftrace
5715 * This function should be used by panic code. It stops ftrace
5716 * but in a not so nice way. If you need to simply kill ftrace
5717 * from a non-atomic section, use ftrace_kill.
5719 void ftrace_kill(void)
5721 ftrace_disabled
= 1;
5723 clear_ftrace_function();
5727 * Test if ftrace is dead or not.
5729 int ftrace_is_dead(void)
5731 return ftrace_disabled
;
5735 * register_ftrace_function - register a function for profiling
5736 * @ops - ops structure that holds the function for profiling.
5738 * Register a function to be called by all functions in the
5741 * Note: @ops->func and all the functions it calls must be labeled
5742 * with "notrace", otherwise it will go into a
5745 int register_ftrace_function(struct ftrace_ops
*ops
)
5749 ftrace_ops_init(ops
);
5751 mutex_lock(&ftrace_lock
);
5753 ret
= ftrace_startup(ops
, 0);
5755 mutex_unlock(&ftrace_lock
);
5759 EXPORT_SYMBOL_GPL(register_ftrace_function
);
5762 * unregister_ftrace_function - unregister a function for profiling.
5763 * @ops - ops structure that holds the function to unregister
5765 * Unregister a function that was added to be called by ftrace profiling.
5767 int unregister_ftrace_function(struct ftrace_ops
*ops
)
5771 mutex_lock(&ftrace_lock
);
5772 ret
= ftrace_shutdown(ops
, 0);
5773 mutex_unlock(&ftrace_lock
);
5777 EXPORT_SYMBOL_GPL(unregister_ftrace_function
);
5780 ftrace_enable_sysctl(struct ctl_table
*table
, int write
,
5781 void __user
*buffer
, size_t *lenp
,
5786 mutex_lock(&ftrace_lock
);
5788 if (unlikely(ftrace_disabled
))
5791 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
5793 if (ret
|| !write
|| (last_ftrace_enabled
== !!ftrace_enabled
))
5796 last_ftrace_enabled
= !!ftrace_enabled
;
5798 if (ftrace_enabled
) {
5800 /* we are starting ftrace again */
5801 if (ftrace_ops_list
!= &ftrace_list_end
)
5802 update_ftrace_function();
5804 ftrace_startup_sysctl();
5807 /* stopping ftrace calls (just send to ftrace_stub) */
5808 ftrace_trace_function
= ftrace_stub
;
5810 ftrace_shutdown_sysctl();
5814 mutex_unlock(&ftrace_lock
);
5818 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5820 static struct ftrace_ops graph_ops
= {
5821 .func
= ftrace_stub
,
5822 .flags
= FTRACE_OPS_FL_RECURSION_SAFE
|
5823 FTRACE_OPS_FL_INITIALIZED
|
5826 #ifdef FTRACE_GRAPH_TRAMP_ADDR
5827 .trampoline
= FTRACE_GRAPH_TRAMP_ADDR
,
5828 /* trampoline_size is only needed for dynamically allocated tramps */
5830 ASSIGN_OPS_HASH(graph_ops
, &global_ops
.local_hash
)
5833 void ftrace_graph_sleep_time_control(bool enable
)
5835 fgraph_sleep_time
= enable
;
5838 void ftrace_graph_graph_time_control(bool enable
)
5840 fgraph_graph_time
= enable
;
5843 int ftrace_graph_entry_stub(struct ftrace_graph_ent
*trace
)
5848 /* The callbacks that hook a function */
5849 trace_func_graph_ret_t ftrace_graph_return
=
5850 (trace_func_graph_ret_t
)ftrace_stub
;
5851 trace_func_graph_ent_t ftrace_graph_entry
= ftrace_graph_entry_stub
;
5852 static trace_func_graph_ent_t __ftrace_graph_entry
= ftrace_graph_entry_stub
;
5854 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
5855 static int alloc_retstack_tasklist(struct ftrace_ret_stack
**ret_stack_list
)
5859 int start
= 0, end
= FTRACE_RETSTACK_ALLOC_SIZE
;
5860 struct task_struct
*g
, *t
;
5862 for (i
= 0; i
< FTRACE_RETSTACK_ALLOC_SIZE
; i
++) {
5863 ret_stack_list
[i
] = kmalloc(FTRACE_RETFUNC_DEPTH
5864 * sizeof(struct ftrace_ret_stack
),
5866 if (!ret_stack_list
[i
]) {
5874 read_lock(&tasklist_lock
);
5875 do_each_thread(g
, t
) {
5881 if (t
->ret_stack
== NULL
) {
5882 atomic_set(&t
->tracing_graph_pause
, 0);
5883 atomic_set(&t
->trace_overrun
, 0);
5884 t
->curr_ret_stack
= -1;
5885 /* Make sure the tasks see the -1 first: */
5887 t
->ret_stack
= ret_stack_list
[start
++];
5889 } while_each_thread(g
, t
);
5892 read_unlock(&tasklist_lock
);
5894 for (i
= start
; i
< end
; i
++)
5895 kfree(ret_stack_list
[i
]);
5900 ftrace_graph_probe_sched_switch(void *ignore
, bool preempt
,
5901 struct task_struct
*prev
, struct task_struct
*next
)
5903 unsigned long long timestamp
;
5907 * Does the user want to count the time a function was asleep.
5908 * If so, do not update the time stamps.
5910 if (fgraph_sleep_time
)
5913 timestamp
= trace_clock_local();
5915 prev
->ftrace_timestamp
= timestamp
;
5917 /* only process tasks that we timestamped */
5918 if (!next
->ftrace_timestamp
)
5922 * Update all the counters in next to make up for the
5923 * time next was sleeping.
5925 timestamp
-= next
->ftrace_timestamp
;
5927 for (index
= next
->curr_ret_stack
; index
>= 0; index
--)
5928 next
->ret_stack
[index
].calltime
+= timestamp
;
5931 /* Allocate a return stack for each task */
5932 static int start_graph_tracing(void)
5934 struct ftrace_ret_stack
**ret_stack_list
;
5937 ret_stack_list
= kmalloc(FTRACE_RETSTACK_ALLOC_SIZE
*
5938 sizeof(struct ftrace_ret_stack
*),
5941 if (!ret_stack_list
)
5944 /* The cpu_boot init_task->ret_stack will never be freed */
5945 for_each_online_cpu(cpu
) {
5946 if (!idle_task(cpu
)->ret_stack
)
5947 ftrace_graph_init_idle_task(idle_task(cpu
), cpu
);
5951 ret
= alloc_retstack_tasklist(ret_stack_list
);
5952 } while (ret
== -EAGAIN
);
5955 ret
= register_trace_sched_switch(ftrace_graph_probe_sched_switch
, NULL
);
5957 pr_info("ftrace_graph: Couldn't activate tracepoint"
5958 " probe to kernel_sched_switch\n");
5961 kfree(ret_stack_list
);
5966 * Hibernation protection.
5967 * The state of the current task is too much unstable during
5968 * suspend/restore to disk. We want to protect against that.
5971 ftrace_suspend_notifier_call(struct notifier_block
*bl
, unsigned long state
,
5975 case PM_HIBERNATION_PREPARE
:
5976 pause_graph_tracing();
5979 case PM_POST_HIBERNATION
:
5980 unpause_graph_tracing();
5986 static int ftrace_graph_entry_test(struct ftrace_graph_ent
*trace
)
5988 if (!ftrace_ops_test(&global_ops
, trace
->func
, NULL
))
5990 return __ftrace_graph_entry(trace
);
5994 * The function graph tracer should only trace the functions defined
5995 * by set_ftrace_filter and set_ftrace_notrace. If another function
5996 * tracer ops is registered, the graph tracer requires testing the
5997 * function against the global ops, and not just trace any function
5998 * that any ftrace_ops registered.
6000 static void update_function_graph_func(void)
6002 struct ftrace_ops
*op
;
6003 bool do_test
= false;
6006 * The graph and global ops share the same set of functions
6007 * to test. If any other ops is on the list, then
6008 * the graph tracing needs to test if its the function
6011 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
6012 if (op
!= &global_ops
&& op
!= &graph_ops
&&
6013 op
!= &ftrace_list_end
) {
6015 /* in double loop, break out with goto */
6018 } while_for_each_ftrace_op(op
);
6021 ftrace_graph_entry
= ftrace_graph_entry_test
;
6023 ftrace_graph_entry
= __ftrace_graph_entry
;
6026 static struct notifier_block ftrace_suspend_notifier
= {
6027 .notifier_call
= ftrace_suspend_notifier_call
,
6030 int register_ftrace_graph(trace_func_graph_ret_t retfunc
,
6031 trace_func_graph_ent_t entryfunc
)
6035 mutex_lock(&ftrace_lock
);
6037 /* we currently allow only one tracer registered at a time */
6038 if (ftrace_graph_active
) {
6043 register_pm_notifier(&ftrace_suspend_notifier
);
6045 ftrace_graph_active
++;
6046 ret
= start_graph_tracing();
6048 ftrace_graph_active
--;
6052 ftrace_graph_return
= retfunc
;
6055 * Update the indirect function to the entryfunc, and the
6056 * function that gets called to the entry_test first. Then
6057 * call the update fgraph entry function to determine if
6058 * the entryfunc should be called directly or not.
6060 __ftrace_graph_entry
= entryfunc
;
6061 ftrace_graph_entry
= ftrace_graph_entry_test
;
6062 update_function_graph_func();
6064 ret
= ftrace_startup(&graph_ops
, FTRACE_START_FUNC_RET
);
6066 mutex_unlock(&ftrace_lock
);
6070 void unregister_ftrace_graph(void)
6072 mutex_lock(&ftrace_lock
);
6074 if (unlikely(!ftrace_graph_active
))
6077 ftrace_graph_active
--;
6078 ftrace_graph_return
= (trace_func_graph_ret_t
)ftrace_stub
;
6079 ftrace_graph_entry
= ftrace_graph_entry_stub
;
6080 __ftrace_graph_entry
= ftrace_graph_entry_stub
;
6081 ftrace_shutdown(&graph_ops
, FTRACE_STOP_FUNC_RET
);
6082 unregister_pm_notifier(&ftrace_suspend_notifier
);
6083 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch
, NULL
);
6085 #ifdef CONFIG_DYNAMIC_FTRACE
6087 * Function graph does not allocate the trampoline, but
6088 * other global_ops do. We need to reset the ALLOC_TRAMP flag
6091 global_ops
.trampoline
= save_global_trampoline
;
6092 if (save_global_flags
& FTRACE_OPS_FL_ALLOC_TRAMP
)
6093 global_ops
.flags
|= FTRACE_OPS_FL_ALLOC_TRAMP
;
6097 mutex_unlock(&ftrace_lock
);
6100 static DEFINE_PER_CPU(struct ftrace_ret_stack
*, idle_ret_stack
);
6103 graph_init_task(struct task_struct
*t
, struct ftrace_ret_stack
*ret_stack
)
6105 atomic_set(&t
->tracing_graph_pause
, 0);
6106 atomic_set(&t
->trace_overrun
, 0);
6107 t
->ftrace_timestamp
= 0;
6108 /* make curr_ret_stack visible before we add the ret_stack */
6110 t
->ret_stack
= ret_stack
;
6114 * Allocate a return stack for the idle task. May be the first
6115 * time through, or it may be done by CPU hotplug online.
6117 void ftrace_graph_init_idle_task(struct task_struct
*t
, int cpu
)
6119 t
->curr_ret_stack
= -1;
6121 * The idle task has no parent, it either has its own
6122 * stack or no stack at all.
6125 WARN_ON(t
->ret_stack
!= per_cpu(idle_ret_stack
, cpu
));
6127 if (ftrace_graph_active
) {
6128 struct ftrace_ret_stack
*ret_stack
;
6130 ret_stack
= per_cpu(idle_ret_stack
, cpu
);
6132 ret_stack
= kmalloc(FTRACE_RETFUNC_DEPTH
6133 * sizeof(struct ftrace_ret_stack
),
6137 per_cpu(idle_ret_stack
, cpu
) = ret_stack
;
6139 graph_init_task(t
, ret_stack
);
6143 /* Allocate a return stack for newly created task */
6144 void ftrace_graph_init_task(struct task_struct
*t
)
6146 /* Make sure we do not use the parent ret_stack */
6147 t
->ret_stack
= NULL
;
6148 t
->curr_ret_stack
= -1;
6150 if (ftrace_graph_active
) {
6151 struct ftrace_ret_stack
*ret_stack
;
6153 ret_stack
= kmalloc(FTRACE_RETFUNC_DEPTH
6154 * sizeof(struct ftrace_ret_stack
),
6158 graph_init_task(t
, ret_stack
);
6162 void ftrace_graph_exit_task(struct task_struct
*t
)
6164 struct ftrace_ret_stack
*ret_stack
= t
->ret_stack
;
6166 t
->ret_stack
= NULL
;
6167 /* NULL must become visible to IRQs before we free it: */