1 // SPDX-License-Identifier: GPL-2.0
3 * Infrastructure for profiling code inserted by 'gcc -pg'.
5 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
6 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
8 * Originally ported from the -rt patch by:
9 * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
11 * Based on code in the latency_tracer, that is:
13 * Copyright (C) 2004-2006 Ingo Molnar
14 * Copyright (C) 2004 Nadia Yvette Chambers
17 #include <linux/stop_machine.h>
18 #include <linux/clocksource.h>
19 #include <linux/sched/task.h>
20 #include <linux/kallsyms.h>
21 #include <linux/security.h>
22 #include <linux/seq_file.h>
23 #include <linux/tracefs.h>
24 #include <linux/hardirq.h>
25 #include <linux/kthread.h>
26 #include <linux/uaccess.h>
27 #include <linux/bsearch.h>
28 #include <linux/module.h>
29 #include <linux/ftrace.h>
30 #include <linux/sysctl.h>
31 #include <linux/slab.h>
32 #include <linux/ctype.h>
33 #include <linux/sort.h>
34 #include <linux/list.h>
35 #include <linux/hash.h>
36 #include <linux/rcupdate.h>
37 #include <linux/kprobes.h>
39 #include <trace/events/sched.h>
41 #include <asm/sections.h>
42 #include <asm/setup.h>
44 #include "ftrace_internal.h"
45 #include "trace_output.h"
46 #include "trace_stat.h"
48 #define FTRACE_WARN_ON(cond) \
56 #define FTRACE_WARN_ON_ONCE(cond) \
59 if (WARN_ON_ONCE(___r)) \
64 /* hash bits for specific function selection */
65 #define FTRACE_HASH_BITS 7
66 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
67 #define FTRACE_HASH_DEFAULT_BITS 10
68 #define FTRACE_HASH_MAX_BITS 12
70 #ifdef CONFIG_DYNAMIC_FTRACE
71 #define INIT_OPS_HASH(opsname) \
72 .func_hash = &opsname.local_hash, \
73 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
75 #define INIT_OPS_HASH(opsname)
79 FTRACE_MODIFY_ENABLE_FL
= (1 << 0),
80 FTRACE_MODIFY_MAY_SLEEP_FL
= (1 << 1),
83 struct ftrace_ops ftrace_list_end __read_mostly
= {
85 .flags
= FTRACE_OPS_FL_RECURSION_SAFE
| FTRACE_OPS_FL_STUB
,
86 INIT_OPS_HASH(ftrace_list_end
)
89 /* ftrace_enabled is a method to turn ftrace on or off */
90 int ftrace_enabled __read_mostly
;
91 static int last_ftrace_enabled
;
93 /* Current function tracing op */
94 struct ftrace_ops
*function_trace_op __read_mostly
= &ftrace_list_end
;
95 /* What to set function_trace_op to */
96 static struct ftrace_ops
*set_function_trace_op
;
98 static bool ftrace_pids_enabled(struct ftrace_ops
*ops
)
100 struct trace_array
*tr
;
102 if (!(ops
->flags
& FTRACE_OPS_FL_PID
) || !ops
->private)
107 return tr
->function_pids
!= NULL
;
110 static void ftrace_update_trampoline(struct ftrace_ops
*ops
);
113 * ftrace_disabled is set when an anomaly is discovered.
114 * ftrace_disabled is much stronger than ftrace_enabled.
116 static int ftrace_disabled __read_mostly
;
118 DEFINE_MUTEX(ftrace_lock
);
120 struct ftrace_ops __rcu
*ftrace_ops_list __read_mostly
= &ftrace_list_end
;
121 ftrace_func_t ftrace_trace_function __read_mostly
= ftrace_stub
;
122 struct ftrace_ops global_ops
;
124 #if ARCH_SUPPORTS_FTRACE_OPS
125 static void ftrace_ops_list_func(unsigned long ip
, unsigned long parent_ip
,
126 struct ftrace_ops
*op
, struct pt_regs
*regs
);
128 /* See comment below, where ftrace_ops_list_func is defined */
129 static void ftrace_ops_no_ops(unsigned long ip
, unsigned long parent_ip
);
130 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
133 static inline void ftrace_ops_init(struct ftrace_ops
*ops
)
135 #ifdef CONFIG_DYNAMIC_FTRACE
136 if (!(ops
->flags
& FTRACE_OPS_FL_INITIALIZED
)) {
137 mutex_init(&ops
->local_hash
.regex_lock
);
138 ops
->func_hash
= &ops
->local_hash
;
139 ops
->flags
|= FTRACE_OPS_FL_INITIALIZED
;
144 static void ftrace_pid_func(unsigned long ip
, unsigned long parent_ip
,
145 struct ftrace_ops
*op
, struct pt_regs
*regs
)
147 struct trace_array
*tr
= op
->private;
149 if (tr
&& this_cpu_read(tr
->trace_buffer
.data
->ftrace_ignore_pid
))
152 op
->saved_func(ip
, parent_ip
, op
, regs
);
155 static void ftrace_sync(struct work_struct
*work
)
158 * This function is just a stub to implement a hard force
159 * of synchronize_rcu(). This requires synchronizing
160 * tasks even in userspace and idle.
162 * Yes, function tracing is rude.
166 static void ftrace_sync_ipi(void *data
)
168 /* Probably not needed, but do it anyway */
172 static ftrace_func_t
ftrace_ops_get_list_func(struct ftrace_ops
*ops
)
175 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
176 * then it needs to call the list anyway.
178 if (ops
->flags
& (FTRACE_OPS_FL_DYNAMIC
| FTRACE_OPS_FL_RCU
) ||
179 FTRACE_FORCE_LIST_FUNC
)
180 return ftrace_ops_list_func
;
182 return ftrace_ops_get_func(ops
);
185 static void update_ftrace_function(void)
190 * Prepare the ftrace_ops that the arch callback will use.
191 * If there's only one ftrace_ops registered, the ftrace_ops_list
192 * will point to the ops we want.
194 set_function_trace_op
= rcu_dereference_protected(ftrace_ops_list
,
195 lockdep_is_held(&ftrace_lock
));
197 /* If there's no ftrace_ops registered, just call the stub function */
198 if (set_function_trace_op
== &ftrace_list_end
) {
202 * If we are at the end of the list and this ops is
203 * recursion safe and not dynamic and the arch supports passing ops,
204 * then have the mcount trampoline call the function directly.
206 } else if (rcu_dereference_protected(ftrace_ops_list
->next
,
207 lockdep_is_held(&ftrace_lock
)) == &ftrace_list_end
) {
208 func
= ftrace_ops_get_list_func(ftrace_ops_list
);
211 /* Just use the default ftrace_ops */
212 set_function_trace_op
= &ftrace_list_end
;
213 func
= ftrace_ops_list_func
;
216 update_function_graph_func();
218 /* If there's no change, then do nothing more here */
219 if (ftrace_trace_function
== func
)
223 * If we are using the list function, it doesn't care
224 * about the function_trace_ops.
226 if (func
== ftrace_ops_list_func
) {
227 ftrace_trace_function
= func
;
229 * Don't even bother setting function_trace_ops,
230 * it would be racy to do so anyway.
235 #ifndef CONFIG_DYNAMIC_FTRACE
237 * For static tracing, we need to be a bit more careful.
238 * The function change takes affect immediately. Thus,
239 * we need to coorditate the setting of the function_trace_ops
240 * with the setting of the ftrace_trace_function.
242 * Set the function to the list ops, which will call the
243 * function we want, albeit indirectly, but it handles the
244 * ftrace_ops and doesn't depend on function_trace_op.
246 ftrace_trace_function
= ftrace_ops_list_func
;
248 * Make sure all CPUs see this. Yes this is slow, but static
249 * tracing is slow and nasty to have enabled.
251 schedule_on_each_cpu(ftrace_sync
);
252 /* Now all cpus are using the list ops. */
253 function_trace_op
= set_function_trace_op
;
254 /* Make sure the function_trace_op is visible on all CPUs */
256 /* Nasty way to force a rmb on all cpus */
257 smp_call_function(ftrace_sync_ipi
, NULL
, 1);
258 /* OK, we are all set to update the ftrace_trace_function now! */
259 #endif /* !CONFIG_DYNAMIC_FTRACE */
261 ftrace_trace_function
= func
;
264 static void add_ftrace_ops(struct ftrace_ops __rcu
**list
,
265 struct ftrace_ops
*ops
)
267 rcu_assign_pointer(ops
->next
, *list
);
270 * We are entering ops into the list but another
271 * CPU might be walking that list. We need to make sure
272 * the ops->next pointer is valid before another CPU sees
273 * the ops pointer included into the list.
275 rcu_assign_pointer(*list
, ops
);
278 static int remove_ftrace_ops(struct ftrace_ops __rcu
**list
,
279 struct ftrace_ops
*ops
)
281 struct ftrace_ops
**p
;
284 * If we are removing the last function, then simply point
285 * to the ftrace_stub.
287 if (rcu_dereference_protected(*list
,
288 lockdep_is_held(&ftrace_lock
)) == ops
&&
289 rcu_dereference_protected(ops
->next
,
290 lockdep_is_held(&ftrace_lock
)) == &ftrace_list_end
) {
291 *list
= &ftrace_list_end
;
295 for (p
= list
; *p
!= &ftrace_list_end
; p
= &(*p
)->next
)
306 static void ftrace_update_trampoline(struct ftrace_ops
*ops
);
308 int __register_ftrace_function(struct ftrace_ops
*ops
)
310 if (ops
->flags
& FTRACE_OPS_FL_DELETED
)
313 if (WARN_ON(ops
->flags
& FTRACE_OPS_FL_ENABLED
))
316 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
318 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
319 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
320 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
322 if (ops
->flags
& FTRACE_OPS_FL_SAVE_REGS
&&
323 !(ops
->flags
& FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED
))
326 if (ops
->flags
& FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED
)
327 ops
->flags
|= FTRACE_OPS_FL_SAVE_REGS
;
329 if (!ftrace_enabled
&& (ops
->flags
& FTRACE_OPS_FL_PERMANENT
))
332 if (!core_kernel_data((unsigned long)ops
))
333 ops
->flags
|= FTRACE_OPS_FL_DYNAMIC
;
335 add_ftrace_ops(&ftrace_ops_list
, ops
);
337 /* Always save the function, and reset at unregistering */
338 ops
->saved_func
= ops
->func
;
340 if (ftrace_pids_enabled(ops
))
341 ops
->func
= ftrace_pid_func
;
343 ftrace_update_trampoline(ops
);
346 update_ftrace_function();
351 int __unregister_ftrace_function(struct ftrace_ops
*ops
)
355 if (WARN_ON(!(ops
->flags
& FTRACE_OPS_FL_ENABLED
)))
358 ret
= remove_ftrace_ops(&ftrace_ops_list
, ops
);
364 update_ftrace_function();
366 ops
->func
= ops
->saved_func
;
371 static void ftrace_update_pid_func(void)
373 struct ftrace_ops
*op
;
375 /* Only do something if we are tracing something */
376 if (ftrace_trace_function
== ftrace_stub
)
379 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
380 if (op
->flags
& FTRACE_OPS_FL_PID
) {
381 op
->func
= ftrace_pids_enabled(op
) ?
382 ftrace_pid_func
: op
->saved_func
;
383 ftrace_update_trampoline(op
);
385 } while_for_each_ftrace_op(op
);
387 update_ftrace_function();
390 #ifdef CONFIG_FUNCTION_PROFILER
391 struct ftrace_profile
{
392 struct hlist_node node
;
394 unsigned long counter
;
395 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
396 unsigned long long time
;
397 unsigned long long time_squared
;
401 struct ftrace_profile_page
{
402 struct ftrace_profile_page
*next
;
404 struct ftrace_profile records
[];
407 struct ftrace_profile_stat
{
409 struct hlist_head
*hash
;
410 struct ftrace_profile_page
*pages
;
411 struct ftrace_profile_page
*start
;
412 struct tracer_stat stat
;
415 #define PROFILE_RECORDS_SIZE \
416 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
418 #define PROFILES_PER_PAGE \
419 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
421 static int ftrace_profile_enabled __read_mostly
;
423 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
424 static DEFINE_MUTEX(ftrace_profile_lock
);
426 static DEFINE_PER_CPU(struct ftrace_profile_stat
, ftrace_profile_stats
);
428 #define FTRACE_PROFILE_HASH_BITS 10
429 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
432 function_stat_next(void *v
, int idx
)
434 struct ftrace_profile
*rec
= v
;
435 struct ftrace_profile_page
*pg
;
437 pg
= (struct ftrace_profile_page
*)((unsigned long)rec
& PAGE_MASK
);
443 if ((void *)rec
>= (void *)&pg
->records
[pg
->index
]) {
447 rec
= &pg
->records
[0];
455 static void *function_stat_start(struct tracer_stat
*trace
)
457 struct ftrace_profile_stat
*stat
=
458 container_of(trace
, struct ftrace_profile_stat
, stat
);
460 if (!stat
|| !stat
->start
)
463 return function_stat_next(&stat
->start
->records
[0], 0);
466 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
467 /* function graph compares on total time */
468 static int function_stat_cmp(const void *p1
, const void *p2
)
470 const struct ftrace_profile
*a
= p1
;
471 const struct ftrace_profile
*b
= p2
;
473 if (a
->time
< b
->time
)
475 if (a
->time
> b
->time
)
481 /* not function graph compares against hits */
482 static int function_stat_cmp(const void *p1
, const void *p2
)
484 const struct ftrace_profile
*a
= p1
;
485 const struct ftrace_profile
*b
= p2
;
487 if (a
->counter
< b
->counter
)
489 if (a
->counter
> b
->counter
)
496 static int function_stat_headers(struct seq_file
*m
)
498 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
499 seq_puts(m
, " Function "
502 "--- ---- --- ---\n");
504 seq_puts(m
, " Function Hit\n"
510 static int function_stat_show(struct seq_file
*m
, void *v
)
512 struct ftrace_profile
*rec
= v
;
513 char str
[KSYM_SYMBOL_LEN
];
515 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
516 static struct trace_seq s
;
517 unsigned long long avg
;
518 unsigned long long stddev
;
520 mutex_lock(&ftrace_profile_lock
);
522 /* we raced with function_profile_reset() */
523 if (unlikely(rec
->counter
== 0)) {
528 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
530 do_div(avg
, rec
->counter
);
531 if (tracing_thresh
&& (avg
< tracing_thresh
))
535 kallsyms_lookup(rec
->ip
, NULL
, NULL
, NULL
, str
);
536 seq_printf(m
, " %-30.30s %10lu", str
, rec
->counter
);
538 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
541 /* Sample standard deviation (s^2) */
542 if (rec
->counter
<= 1)
546 * Apply Welford's method:
547 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
549 stddev
= rec
->counter
* rec
->time_squared
-
550 rec
->time
* rec
->time
;
553 * Divide only 1000 for ns^2 -> us^2 conversion.
554 * trace_print_graph_duration will divide 1000 again.
556 do_div(stddev
, rec
->counter
* (rec
->counter
- 1) * 1000);
560 trace_print_graph_duration(rec
->time
, &s
);
561 trace_seq_puts(&s
, " ");
562 trace_print_graph_duration(avg
, &s
);
563 trace_seq_puts(&s
, " ");
564 trace_print_graph_duration(stddev
, &s
);
565 trace_print_seq(m
, &s
);
569 mutex_unlock(&ftrace_profile_lock
);
574 static void ftrace_profile_reset(struct ftrace_profile_stat
*stat
)
576 struct ftrace_profile_page
*pg
;
578 pg
= stat
->pages
= stat
->start
;
581 memset(pg
->records
, 0, PROFILE_RECORDS_SIZE
);
586 memset(stat
->hash
, 0,
587 FTRACE_PROFILE_HASH_SIZE
* sizeof(struct hlist_head
));
590 int ftrace_profile_pages_init(struct ftrace_profile_stat
*stat
)
592 struct ftrace_profile_page
*pg
;
597 /* If we already allocated, do nothing */
601 stat
->pages
= (void *)get_zeroed_page(GFP_KERNEL
);
605 #ifdef CONFIG_DYNAMIC_FTRACE
606 functions
= ftrace_update_tot_cnt
;
609 * We do not know the number of functions that exist because
610 * dynamic tracing is what counts them. With past experience
611 * we have around 20K functions. That should be more than enough.
612 * It is highly unlikely we will execute every function in
618 pg
= stat
->start
= stat
->pages
;
620 pages
= DIV_ROUND_UP(functions
, PROFILES_PER_PAGE
);
622 for (i
= 1; i
< pages
; i
++) {
623 pg
->next
= (void *)get_zeroed_page(GFP_KERNEL
);
634 unsigned long tmp
= (unsigned long)pg
;
646 static int ftrace_profile_init_cpu(int cpu
)
648 struct ftrace_profile_stat
*stat
;
651 stat
= &per_cpu(ftrace_profile_stats
, cpu
);
654 /* If the profile is already created, simply reset it */
655 ftrace_profile_reset(stat
);
660 * We are profiling all functions, but usually only a few thousand
661 * functions are hit. We'll make a hash of 1024 items.
663 size
= FTRACE_PROFILE_HASH_SIZE
;
665 stat
->hash
= kcalloc(size
, sizeof(struct hlist_head
), GFP_KERNEL
);
670 /* Preallocate the function profiling pages */
671 if (ftrace_profile_pages_init(stat
) < 0) {
680 static int ftrace_profile_init(void)
685 for_each_possible_cpu(cpu
) {
686 ret
= ftrace_profile_init_cpu(cpu
);
694 /* interrupts must be disabled */
695 static struct ftrace_profile
*
696 ftrace_find_profiled_func(struct ftrace_profile_stat
*stat
, unsigned long ip
)
698 struct ftrace_profile
*rec
;
699 struct hlist_head
*hhd
;
702 key
= hash_long(ip
, FTRACE_PROFILE_HASH_BITS
);
703 hhd
= &stat
->hash
[key
];
705 if (hlist_empty(hhd
))
708 hlist_for_each_entry_rcu_notrace(rec
, hhd
, node
) {
716 static void ftrace_add_profile(struct ftrace_profile_stat
*stat
,
717 struct ftrace_profile
*rec
)
721 key
= hash_long(rec
->ip
, FTRACE_PROFILE_HASH_BITS
);
722 hlist_add_head_rcu(&rec
->node
, &stat
->hash
[key
]);
726 * The memory is already allocated, this simply finds a new record to use.
728 static struct ftrace_profile
*
729 ftrace_profile_alloc(struct ftrace_profile_stat
*stat
, unsigned long ip
)
731 struct ftrace_profile
*rec
= NULL
;
733 /* prevent recursion (from NMIs) */
734 if (atomic_inc_return(&stat
->disabled
) != 1)
738 * Try to find the function again since an NMI
739 * could have added it
741 rec
= ftrace_find_profiled_func(stat
, ip
);
745 if (stat
->pages
->index
== PROFILES_PER_PAGE
) {
746 if (!stat
->pages
->next
)
748 stat
->pages
= stat
->pages
->next
;
751 rec
= &stat
->pages
->records
[stat
->pages
->index
++];
753 ftrace_add_profile(stat
, rec
);
756 atomic_dec(&stat
->disabled
);
762 function_profile_call(unsigned long ip
, unsigned long parent_ip
,
763 struct ftrace_ops
*ops
, struct pt_regs
*regs
)
765 struct ftrace_profile_stat
*stat
;
766 struct ftrace_profile
*rec
;
769 if (!ftrace_profile_enabled
)
772 local_irq_save(flags
);
774 stat
= this_cpu_ptr(&ftrace_profile_stats
);
775 if (!stat
->hash
|| !ftrace_profile_enabled
)
778 rec
= ftrace_find_profiled_func(stat
, ip
);
780 rec
= ftrace_profile_alloc(stat
, ip
);
787 local_irq_restore(flags
);
790 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
791 static bool fgraph_graph_time
= true;
793 void ftrace_graph_graph_time_control(bool enable
)
795 fgraph_graph_time
= enable
;
798 static int profile_graph_entry(struct ftrace_graph_ent
*trace
)
800 struct ftrace_ret_stack
*ret_stack
;
802 function_profile_call(trace
->func
, 0, NULL
, NULL
);
804 /* If function graph is shutting down, ret_stack can be NULL */
805 if (!current
->ret_stack
)
808 ret_stack
= ftrace_graph_get_ret_stack(current
, 0);
810 ret_stack
->subtime
= 0;
815 static void profile_graph_return(struct ftrace_graph_ret
*trace
)
817 struct ftrace_ret_stack
*ret_stack
;
818 struct ftrace_profile_stat
*stat
;
819 unsigned long long calltime
;
820 struct ftrace_profile
*rec
;
823 local_irq_save(flags
);
824 stat
= this_cpu_ptr(&ftrace_profile_stats
);
825 if (!stat
->hash
|| !ftrace_profile_enabled
)
828 /* If the calltime was zero'd ignore it */
829 if (!trace
->calltime
)
832 calltime
= trace
->rettime
- trace
->calltime
;
834 if (!fgraph_graph_time
) {
836 /* Append this call time to the parent time to subtract */
837 ret_stack
= ftrace_graph_get_ret_stack(current
, 1);
839 ret_stack
->subtime
+= calltime
;
841 ret_stack
= ftrace_graph_get_ret_stack(current
, 0);
842 if (ret_stack
&& ret_stack
->subtime
< calltime
)
843 calltime
-= ret_stack
->subtime
;
848 rec
= ftrace_find_profiled_func(stat
, trace
->func
);
850 rec
->time
+= calltime
;
851 rec
->time_squared
+= calltime
* calltime
;
855 local_irq_restore(flags
);
858 static struct fgraph_ops fprofiler_ops
= {
859 .entryfunc
= &profile_graph_entry
,
860 .retfunc
= &profile_graph_return
,
863 static int register_ftrace_profiler(void)
865 return register_ftrace_graph(&fprofiler_ops
);
868 static void unregister_ftrace_profiler(void)
870 unregister_ftrace_graph(&fprofiler_ops
);
873 static struct ftrace_ops ftrace_profile_ops __read_mostly
= {
874 .func
= function_profile_call
,
875 .flags
= FTRACE_OPS_FL_RECURSION_SAFE
| FTRACE_OPS_FL_INITIALIZED
,
876 INIT_OPS_HASH(ftrace_profile_ops
)
879 static int register_ftrace_profiler(void)
881 return register_ftrace_function(&ftrace_profile_ops
);
884 static void unregister_ftrace_profiler(void)
886 unregister_ftrace_function(&ftrace_profile_ops
);
888 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
891 ftrace_profile_write(struct file
*filp
, const char __user
*ubuf
,
892 size_t cnt
, loff_t
*ppos
)
897 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
903 mutex_lock(&ftrace_profile_lock
);
904 if (ftrace_profile_enabled
^ val
) {
906 ret
= ftrace_profile_init();
912 ret
= register_ftrace_profiler();
917 ftrace_profile_enabled
= 1;
919 ftrace_profile_enabled
= 0;
921 * unregister_ftrace_profiler calls stop_machine
922 * so this acts like an synchronize_rcu.
924 unregister_ftrace_profiler();
928 mutex_unlock(&ftrace_profile_lock
);
936 ftrace_profile_read(struct file
*filp
, char __user
*ubuf
,
937 size_t cnt
, loff_t
*ppos
)
939 char buf
[64]; /* big enough to hold a number */
942 r
= sprintf(buf
, "%u\n", ftrace_profile_enabled
);
943 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
946 static const struct file_operations ftrace_profile_fops
= {
947 .open
= tracing_open_generic
,
948 .read
= ftrace_profile_read
,
949 .write
= ftrace_profile_write
,
950 .llseek
= default_llseek
,
953 /* used to initialize the real stat files */
954 static struct tracer_stat function_stats __initdata
= {
956 .stat_start
= function_stat_start
,
957 .stat_next
= function_stat_next
,
958 .stat_cmp
= function_stat_cmp
,
959 .stat_headers
= function_stat_headers
,
960 .stat_show
= function_stat_show
963 static __init
void ftrace_profile_tracefs(struct dentry
*d_tracer
)
965 struct ftrace_profile_stat
*stat
;
966 struct dentry
*entry
;
971 for_each_possible_cpu(cpu
) {
972 stat
= &per_cpu(ftrace_profile_stats
, cpu
);
974 name
= kasprintf(GFP_KERNEL
, "function%d", cpu
);
977 * The files created are permanent, if something happens
978 * we still do not free memory.
981 "Could not allocate stat file for cpu %d\n",
985 stat
->stat
= function_stats
;
986 stat
->stat
.name
= name
;
987 ret
= register_stat_tracer(&stat
->stat
);
990 "Could not register function stat for cpu %d\n",
997 entry
= tracefs_create_file("function_profile_enabled", 0644,
998 d_tracer
, NULL
, &ftrace_profile_fops
);
1000 pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
1003 #else /* CONFIG_FUNCTION_PROFILER */
1004 static __init
void ftrace_profile_tracefs(struct dentry
*d_tracer
)
1007 #endif /* CONFIG_FUNCTION_PROFILER */
1009 #ifdef CONFIG_DYNAMIC_FTRACE
1011 static struct ftrace_ops
*removed_ops
;
1014 * Set when doing a global update, like enabling all recs or disabling them.
1015 * It is not set when just updating a single ftrace_ops.
1017 static bool update_all_ops
;
1019 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1020 # error Dynamic ftrace depends on MCOUNT_RECORD
1023 struct ftrace_func_probe
{
1024 struct ftrace_probe_ops
*probe_ops
;
1025 struct ftrace_ops ops
;
1026 struct trace_array
*tr
;
1027 struct list_head list
;
1033 * We make these constant because no one should touch them,
1034 * but they are used as the default "empty hash", to avoid allocating
1035 * it all the time. These are in a read only section such that if
1036 * anyone does try to modify it, it will cause an exception.
1038 static const struct hlist_head empty_buckets
[1];
1039 static const struct ftrace_hash empty_hash
= {
1040 .buckets
= (struct hlist_head
*)empty_buckets
,
1042 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1044 struct ftrace_ops global_ops
= {
1045 .func
= ftrace_stub
,
1046 .local_hash
.notrace_hash
= EMPTY_HASH
,
1047 .local_hash
.filter_hash
= EMPTY_HASH
,
1048 INIT_OPS_HASH(global_ops
)
1049 .flags
= FTRACE_OPS_FL_RECURSION_SAFE
|
1050 FTRACE_OPS_FL_INITIALIZED
|
1055 * Used by the stack undwinder to know about dynamic ftrace trampolines.
1057 struct ftrace_ops
*ftrace_ops_trampoline(unsigned long addr
)
1059 struct ftrace_ops
*op
= NULL
;
1062 * Some of the ops may be dynamically allocated,
1063 * they are freed after a synchronize_rcu().
1065 preempt_disable_notrace();
1067 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
1069 * This is to check for dynamically allocated trampolines.
1070 * Trampolines that are in kernel text will have
1071 * core_kernel_text() return true.
1073 if (op
->trampoline
&& op
->trampoline_size
)
1074 if (addr
>= op
->trampoline
&&
1075 addr
< op
->trampoline
+ op
->trampoline_size
) {
1076 preempt_enable_notrace();
1079 } while_for_each_ftrace_op(op
);
1080 preempt_enable_notrace();
1086 * This is used by __kernel_text_address() to return true if the
1087 * address is on a dynamically allocated trampoline that would
1088 * not return true for either core_kernel_text() or
1089 * is_module_text_address().
1091 bool is_ftrace_trampoline(unsigned long addr
)
1093 return ftrace_ops_trampoline(addr
) != NULL
;
1096 struct ftrace_page
{
1097 struct ftrace_page
*next
;
1098 struct dyn_ftrace
*records
;
1103 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1104 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1106 /* estimate from running different kernels */
1107 #define NR_TO_INIT 10000
1109 static struct ftrace_page
*ftrace_pages_start
;
1110 static struct ftrace_page
*ftrace_pages
;
1112 static __always_inline
unsigned long
1113 ftrace_hash_key(struct ftrace_hash
*hash
, unsigned long ip
)
1115 if (hash
->size_bits
> 0)
1116 return hash_long(ip
, hash
->size_bits
);
1121 /* Only use this function if ftrace_hash_empty() has already been tested */
1122 static __always_inline
struct ftrace_func_entry
*
1123 __ftrace_lookup_ip(struct ftrace_hash
*hash
, unsigned long ip
)
1126 struct ftrace_func_entry
*entry
;
1127 struct hlist_head
*hhd
;
1129 key
= ftrace_hash_key(hash
, ip
);
1130 hhd
= &hash
->buckets
[key
];
1132 hlist_for_each_entry_rcu_notrace(entry
, hhd
, hlist
) {
1133 if (entry
->ip
== ip
)
1140 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1141 * @hash: The hash to look at
1142 * @ip: The instruction pointer to test
1144 * Search a given @hash to see if a given instruction pointer (@ip)
1147 * Returns the entry that holds the @ip if found. NULL otherwise.
1149 struct ftrace_func_entry
*
1150 ftrace_lookup_ip(struct ftrace_hash
*hash
, unsigned long ip
)
1152 if (ftrace_hash_empty(hash
))
1155 return __ftrace_lookup_ip(hash
, ip
);
1158 static void __add_hash_entry(struct ftrace_hash
*hash
,
1159 struct ftrace_func_entry
*entry
)
1161 struct hlist_head
*hhd
;
1164 key
= ftrace_hash_key(hash
, entry
->ip
);
1165 hhd
= &hash
->buckets
[key
];
1166 hlist_add_head(&entry
->hlist
, hhd
);
1170 static int add_hash_entry(struct ftrace_hash
*hash
, unsigned long ip
)
1172 struct ftrace_func_entry
*entry
;
1174 entry
= kmalloc(sizeof(*entry
), GFP_KERNEL
);
1179 __add_hash_entry(hash
, entry
);
1185 free_hash_entry(struct ftrace_hash
*hash
,
1186 struct ftrace_func_entry
*entry
)
1188 hlist_del(&entry
->hlist
);
1194 remove_hash_entry(struct ftrace_hash
*hash
,
1195 struct ftrace_func_entry
*entry
)
1197 hlist_del_rcu(&entry
->hlist
);
1201 static void ftrace_hash_clear(struct ftrace_hash
*hash
)
1203 struct hlist_head
*hhd
;
1204 struct hlist_node
*tn
;
1205 struct ftrace_func_entry
*entry
;
1206 int size
= 1 << hash
->size_bits
;
1212 for (i
= 0; i
< size
; i
++) {
1213 hhd
= &hash
->buckets
[i
];
1214 hlist_for_each_entry_safe(entry
, tn
, hhd
, hlist
)
1215 free_hash_entry(hash
, entry
);
1217 FTRACE_WARN_ON(hash
->count
);
1220 static void free_ftrace_mod(struct ftrace_mod_load
*ftrace_mod
)
1222 list_del(&ftrace_mod
->list
);
1223 kfree(ftrace_mod
->module
);
1224 kfree(ftrace_mod
->func
);
1228 static void clear_ftrace_mod_list(struct list_head
*head
)
1230 struct ftrace_mod_load
*p
, *n
;
1232 /* stack tracer isn't supported yet */
1236 mutex_lock(&ftrace_lock
);
1237 list_for_each_entry_safe(p
, n
, head
, list
)
1239 mutex_unlock(&ftrace_lock
);
1242 static void free_ftrace_hash(struct ftrace_hash
*hash
)
1244 if (!hash
|| hash
== EMPTY_HASH
)
1246 ftrace_hash_clear(hash
);
1247 kfree(hash
->buckets
);
1251 static void __free_ftrace_hash_rcu(struct rcu_head
*rcu
)
1253 struct ftrace_hash
*hash
;
1255 hash
= container_of(rcu
, struct ftrace_hash
, rcu
);
1256 free_ftrace_hash(hash
);
1259 static void free_ftrace_hash_rcu(struct ftrace_hash
*hash
)
1261 if (!hash
|| hash
== EMPTY_HASH
)
1263 call_rcu(&hash
->rcu
, __free_ftrace_hash_rcu
);
1266 void ftrace_free_filter(struct ftrace_ops
*ops
)
1268 ftrace_ops_init(ops
);
1269 free_ftrace_hash(ops
->func_hash
->filter_hash
);
1270 free_ftrace_hash(ops
->func_hash
->notrace_hash
);
1273 static struct ftrace_hash
*alloc_ftrace_hash(int size_bits
)
1275 struct ftrace_hash
*hash
;
1278 hash
= kzalloc(sizeof(*hash
), GFP_KERNEL
);
1282 size
= 1 << size_bits
;
1283 hash
->buckets
= kcalloc(size
, sizeof(*hash
->buckets
), GFP_KERNEL
);
1285 if (!hash
->buckets
) {
1290 hash
->size_bits
= size_bits
;
1296 static int ftrace_add_mod(struct trace_array
*tr
,
1297 const char *func
, const char *module
,
1300 struct ftrace_mod_load
*ftrace_mod
;
1301 struct list_head
*mod_head
= enable
? &tr
->mod_trace
: &tr
->mod_notrace
;
1303 ftrace_mod
= kzalloc(sizeof(*ftrace_mod
), GFP_KERNEL
);
1307 ftrace_mod
->func
= kstrdup(func
, GFP_KERNEL
);
1308 ftrace_mod
->module
= kstrdup(module
, GFP_KERNEL
);
1309 ftrace_mod
->enable
= enable
;
1311 if (!ftrace_mod
->func
|| !ftrace_mod
->module
)
1314 list_add(&ftrace_mod
->list
, mod_head
);
1319 free_ftrace_mod(ftrace_mod
);
1324 static struct ftrace_hash
*
1325 alloc_and_copy_ftrace_hash(int size_bits
, struct ftrace_hash
*hash
)
1327 struct ftrace_func_entry
*entry
;
1328 struct ftrace_hash
*new_hash
;
1333 new_hash
= alloc_ftrace_hash(size_bits
);
1338 new_hash
->flags
= hash
->flags
;
1341 if (ftrace_hash_empty(hash
))
1344 size
= 1 << hash
->size_bits
;
1345 for (i
= 0; i
< size
; i
++) {
1346 hlist_for_each_entry(entry
, &hash
->buckets
[i
], hlist
) {
1347 ret
= add_hash_entry(new_hash
, entry
->ip
);
1353 FTRACE_WARN_ON(new_hash
->count
!= hash
->count
);
1358 free_ftrace_hash(new_hash
);
1363 ftrace_hash_rec_disable_modify(struct ftrace_ops
*ops
, int filter_hash
);
1365 ftrace_hash_rec_enable_modify(struct ftrace_ops
*ops
, int filter_hash
);
1367 static int ftrace_hash_ipmodify_update(struct ftrace_ops
*ops
,
1368 struct ftrace_hash
*new_hash
);
1370 static struct ftrace_hash
*dup_hash(struct ftrace_hash
*src
, int size
)
1372 struct ftrace_func_entry
*entry
;
1373 struct ftrace_hash
*new_hash
;
1374 struct hlist_head
*hhd
;
1375 struct hlist_node
*tn
;
1380 * Make the hash size about 1/2 the # found
1382 for (size
/= 2; size
; size
>>= 1)
1385 /* Don't allocate too much */
1386 if (bits
> FTRACE_HASH_MAX_BITS
)
1387 bits
= FTRACE_HASH_MAX_BITS
;
1389 new_hash
= alloc_ftrace_hash(bits
);
1393 new_hash
->flags
= src
->flags
;
1395 size
= 1 << src
->size_bits
;
1396 for (i
= 0; i
< size
; i
++) {
1397 hhd
= &src
->buckets
[i
];
1398 hlist_for_each_entry_safe(entry
, tn
, hhd
, hlist
) {
1399 remove_hash_entry(src
, entry
);
1400 __add_hash_entry(new_hash
, entry
);
1406 static struct ftrace_hash
*
1407 __ftrace_hash_move(struct ftrace_hash
*src
)
1409 int size
= src
->count
;
1412 * If the new source is empty, just return the empty_hash.
1414 if (ftrace_hash_empty(src
))
1417 return dup_hash(src
, size
);
1421 ftrace_hash_move(struct ftrace_ops
*ops
, int enable
,
1422 struct ftrace_hash
**dst
, struct ftrace_hash
*src
)
1424 struct ftrace_hash
*new_hash
;
1427 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1428 if (ops
->flags
& FTRACE_OPS_FL_IPMODIFY
&& !enable
)
1431 new_hash
= __ftrace_hash_move(src
);
1435 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1437 /* IPMODIFY should be updated only when filter_hash updating */
1438 ret
= ftrace_hash_ipmodify_update(ops
, new_hash
);
1440 free_ftrace_hash(new_hash
);
1446 * Remove the current set, update the hash and add
1449 ftrace_hash_rec_disable_modify(ops
, enable
);
1451 rcu_assign_pointer(*dst
, new_hash
);
1453 ftrace_hash_rec_enable_modify(ops
, enable
);
1458 static bool hash_contains_ip(unsigned long ip
,
1459 struct ftrace_ops_hash
*hash
)
1462 * The function record is a match if it exists in the filter
1463 * hash and not in the notrace hash. Note, an emty hash is
1464 * considered a match for the filter hash, but an empty
1465 * notrace hash is considered not in the notrace hash.
1467 return (ftrace_hash_empty(hash
->filter_hash
) ||
1468 __ftrace_lookup_ip(hash
->filter_hash
, ip
)) &&
1469 (ftrace_hash_empty(hash
->notrace_hash
) ||
1470 !__ftrace_lookup_ip(hash
->notrace_hash
, ip
));
1474 * Test the hashes for this ops to see if we want to call
1475 * the ops->func or not.
1477 * It's a match if the ip is in the ops->filter_hash or
1478 * the filter_hash does not exist or is empty,
1480 * the ip is not in the ops->notrace_hash.
1482 * This needs to be called with preemption disabled as
1483 * the hashes are freed with call_rcu().
1486 ftrace_ops_test(struct ftrace_ops
*ops
, unsigned long ip
, void *regs
)
1488 struct ftrace_ops_hash hash
;
1491 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1493 * There's a small race when adding ops that the ftrace handler
1494 * that wants regs, may be called without them. We can not
1495 * allow that handler to be called if regs is NULL.
1497 if (regs
== NULL
&& (ops
->flags
& FTRACE_OPS_FL_SAVE_REGS
))
1501 rcu_assign_pointer(hash
.filter_hash
, ops
->func_hash
->filter_hash
);
1502 rcu_assign_pointer(hash
.notrace_hash
, ops
->func_hash
->notrace_hash
);
1504 if (hash_contains_ip(ip
, &hash
))
1513 * This is a double for. Do not use 'break' to break out of the loop,
1514 * you must use a goto.
1516 #define do_for_each_ftrace_rec(pg, rec) \
1517 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1519 for (_____i = 0; _____i < pg->index; _____i++) { \
1520 rec = &pg->records[_____i];
1522 #define while_for_each_ftrace_rec() \
1527 static int ftrace_cmp_recs(const void *a
, const void *b
)
1529 const struct dyn_ftrace
*key
= a
;
1530 const struct dyn_ftrace
*rec
= b
;
1532 if (key
->flags
< rec
->ip
)
1534 if (key
->ip
>= rec
->ip
+ MCOUNT_INSN_SIZE
)
1539 static struct dyn_ftrace
*lookup_rec(unsigned long start
, unsigned long end
)
1541 struct ftrace_page
*pg
;
1542 struct dyn_ftrace
*rec
= NULL
;
1543 struct dyn_ftrace key
;
1546 key
.flags
= end
; /* overload flags, as it is unsigned long */
1548 for (pg
= ftrace_pages_start
; pg
; pg
= pg
->next
) {
1549 if (end
< pg
->records
[0].ip
||
1550 start
>= (pg
->records
[pg
->index
- 1].ip
+ MCOUNT_INSN_SIZE
))
1552 rec
= bsearch(&key
, pg
->records
, pg
->index
,
1553 sizeof(struct dyn_ftrace
),
1560 * ftrace_location_range - return the first address of a traced location
1561 * if it touches the given ip range
1562 * @start: start of range to search.
1563 * @end: end of range to search (inclusive). @end points to the last byte
1566 * Returns rec->ip if the related ftrace location is a least partly within
1567 * the given address range. That is, the first address of the instruction
1568 * that is either a NOP or call to the function tracer. It checks the ftrace
1569 * internal tables to determine if the address belongs or not.
1571 unsigned long ftrace_location_range(unsigned long start
, unsigned long end
)
1573 struct dyn_ftrace
*rec
;
1575 rec
= lookup_rec(start
, end
);
1583 * ftrace_location - return true if the ip giving is a traced location
1584 * @ip: the instruction pointer to check
1586 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1587 * That is, the instruction that is either a NOP or call to
1588 * the function tracer. It checks the ftrace internal tables to
1589 * determine if the address belongs or not.
1591 unsigned long ftrace_location(unsigned long ip
)
1593 return ftrace_location_range(ip
, ip
);
1597 * ftrace_text_reserved - return true if range contains an ftrace location
1598 * @start: start of range to search
1599 * @end: end of range to search (inclusive). @end points to the last byte to check.
1601 * Returns 1 if @start and @end contains a ftrace location.
1602 * That is, the instruction that is either a NOP or call to
1603 * the function tracer. It checks the ftrace internal tables to
1604 * determine if the address belongs or not.
1606 int ftrace_text_reserved(const void *start
, const void *end
)
1610 ret
= ftrace_location_range((unsigned long)start
,
1611 (unsigned long)end
);
1616 /* Test if ops registered to this rec needs regs */
1617 static bool test_rec_ops_needs_regs(struct dyn_ftrace
*rec
)
1619 struct ftrace_ops
*ops
;
1620 bool keep_regs
= false;
1622 for (ops
= ftrace_ops_list
;
1623 ops
!= &ftrace_list_end
; ops
= ops
->next
) {
1624 /* pass rec in as regs to have non-NULL val */
1625 if (ftrace_ops_test(ops
, rec
->ip
, rec
)) {
1626 if (ops
->flags
& FTRACE_OPS_FL_SAVE_REGS
) {
1636 static struct ftrace_ops
*
1637 ftrace_find_tramp_ops_any(struct dyn_ftrace
*rec
);
1638 static struct ftrace_ops
*
1639 ftrace_find_tramp_ops_next(struct dyn_ftrace
*rec
, struct ftrace_ops
*ops
);
1641 static bool __ftrace_hash_rec_update(struct ftrace_ops
*ops
,
1645 struct ftrace_hash
*hash
;
1646 struct ftrace_hash
*other_hash
;
1647 struct ftrace_page
*pg
;
1648 struct dyn_ftrace
*rec
;
1649 bool update
= false;
1653 /* Only update if the ops has been registered */
1654 if (!(ops
->flags
& FTRACE_OPS_FL_ENABLED
))
1658 * In the filter_hash case:
1659 * If the count is zero, we update all records.
1660 * Otherwise we just update the items in the hash.
1662 * In the notrace_hash case:
1663 * We enable the update in the hash.
1664 * As disabling notrace means enabling the tracing,
1665 * and enabling notrace means disabling, the inc variable
1669 hash
= ops
->func_hash
->filter_hash
;
1670 other_hash
= ops
->func_hash
->notrace_hash
;
1671 if (ftrace_hash_empty(hash
))
1675 hash
= ops
->func_hash
->notrace_hash
;
1676 other_hash
= ops
->func_hash
->filter_hash
;
1678 * If the notrace hash has no items,
1679 * then there's nothing to do.
1681 if (ftrace_hash_empty(hash
))
1685 do_for_each_ftrace_rec(pg
, rec
) {
1686 int in_other_hash
= 0;
1690 if (rec
->flags
& FTRACE_FL_DISABLED
)
1695 * Only the filter_hash affects all records.
1696 * Update if the record is not in the notrace hash.
1698 if (!other_hash
|| !ftrace_lookup_ip(other_hash
, rec
->ip
))
1701 in_hash
= !!ftrace_lookup_ip(hash
, rec
->ip
);
1702 in_other_hash
= !!ftrace_lookup_ip(other_hash
, rec
->ip
);
1705 * If filter_hash is set, we want to match all functions
1706 * that are in the hash but not in the other hash.
1708 * If filter_hash is not set, then we are decrementing.
1709 * That means we match anything that is in the hash
1710 * and also in the other_hash. That is, we need to turn
1711 * off functions in the other hash because they are disabled
1714 if (filter_hash
&& in_hash
&& !in_other_hash
)
1716 else if (!filter_hash
&& in_hash
&&
1717 (in_other_hash
|| ftrace_hash_empty(other_hash
)))
1725 if (FTRACE_WARN_ON(ftrace_rec_count(rec
) == FTRACE_REF_MAX
))
1728 if (ops
->flags
& FTRACE_OPS_FL_DIRECT
)
1729 rec
->flags
|= FTRACE_FL_DIRECT
;
1732 * If there's only a single callback registered to a
1733 * function, and the ops has a trampoline registered
1734 * for it, then we can call it directly.
1736 if (ftrace_rec_count(rec
) == 1 && ops
->trampoline
)
1737 rec
->flags
|= FTRACE_FL_TRAMP
;
1740 * If we are adding another function callback
1741 * to this function, and the previous had a
1742 * custom trampoline in use, then we need to go
1743 * back to the default trampoline.
1745 rec
->flags
&= ~FTRACE_FL_TRAMP
;
1748 * If any ops wants regs saved for this function
1749 * then all ops will get saved regs.
1751 if (ops
->flags
& FTRACE_OPS_FL_SAVE_REGS
)
1752 rec
->flags
|= FTRACE_FL_REGS
;
1754 if (FTRACE_WARN_ON(ftrace_rec_count(rec
) == 0))
1759 * Only the internal direct_ops should have the
1760 * DIRECT flag set. Thus, if it is removing a
1761 * function, then that function should no longer
1764 if (ops
->flags
& FTRACE_OPS_FL_DIRECT
)
1765 rec
->flags
&= ~FTRACE_FL_DIRECT
;
1768 * If the rec had REGS enabled and the ops that is
1769 * being removed had REGS set, then see if there is
1770 * still any ops for this record that wants regs.
1771 * If not, we can stop recording them.
1773 if (ftrace_rec_count(rec
) > 0 &&
1774 rec
->flags
& FTRACE_FL_REGS
&&
1775 ops
->flags
& FTRACE_OPS_FL_SAVE_REGS
) {
1776 if (!test_rec_ops_needs_regs(rec
))
1777 rec
->flags
&= ~FTRACE_FL_REGS
;
1781 * The TRAMP needs to be set only if rec count
1782 * is decremented to one, and the ops that is
1783 * left has a trampoline. As TRAMP can only be
1784 * enabled if there is only a single ops attached
1787 if (ftrace_rec_count(rec
) == 1 &&
1788 ftrace_find_tramp_ops_any(rec
))
1789 rec
->flags
|= FTRACE_FL_TRAMP
;
1791 rec
->flags
&= ~FTRACE_FL_TRAMP
;
1794 * flags will be cleared in ftrace_check_record()
1795 * if rec count is zero.
1800 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1801 update
|= ftrace_test_record(rec
, true) != FTRACE_UPDATE_IGNORE
;
1803 /* Shortcut, if we handled all records, we are done. */
1804 if (!all
&& count
== hash
->count
)
1806 } while_for_each_ftrace_rec();
1811 static bool ftrace_hash_rec_disable(struct ftrace_ops
*ops
,
1814 return __ftrace_hash_rec_update(ops
, filter_hash
, 0);
1817 static bool ftrace_hash_rec_enable(struct ftrace_ops
*ops
,
1820 return __ftrace_hash_rec_update(ops
, filter_hash
, 1);
1823 static void ftrace_hash_rec_update_modify(struct ftrace_ops
*ops
,
1824 int filter_hash
, int inc
)
1826 struct ftrace_ops
*op
;
1828 __ftrace_hash_rec_update(ops
, filter_hash
, inc
);
1830 if (ops
->func_hash
!= &global_ops
.local_hash
)
1834 * If the ops shares the global_ops hash, then we need to update
1835 * all ops that are enabled and use this hash.
1837 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
1841 if (op
->func_hash
== &global_ops
.local_hash
)
1842 __ftrace_hash_rec_update(op
, filter_hash
, inc
);
1843 } while_for_each_ftrace_op(op
);
1846 static void ftrace_hash_rec_disable_modify(struct ftrace_ops
*ops
,
1849 ftrace_hash_rec_update_modify(ops
, filter_hash
, 0);
1852 static void ftrace_hash_rec_enable_modify(struct ftrace_ops
*ops
,
1855 ftrace_hash_rec_update_modify(ops
, filter_hash
, 1);
1859 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1860 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1861 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1862 * Note that old_hash and new_hash has below meanings
1863 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1864 * - If the hash is EMPTY_HASH, it hits nothing
1865 * - Anything else hits the recs which match the hash entries.
1867 static int __ftrace_hash_update_ipmodify(struct ftrace_ops
*ops
,
1868 struct ftrace_hash
*old_hash
,
1869 struct ftrace_hash
*new_hash
)
1871 struct ftrace_page
*pg
;
1872 struct dyn_ftrace
*rec
, *end
= NULL
;
1875 /* Only update if the ops has been registered */
1876 if (!(ops
->flags
& FTRACE_OPS_FL_ENABLED
))
1879 if (!(ops
->flags
& FTRACE_OPS_FL_IPMODIFY
))
1883 * Since the IPMODIFY is a very address sensitive action, we do not
1884 * allow ftrace_ops to set all functions to new hash.
1886 if (!new_hash
|| !old_hash
)
1889 /* Update rec->flags */
1890 do_for_each_ftrace_rec(pg
, rec
) {
1892 if (rec
->flags
& FTRACE_FL_DISABLED
)
1895 /* We need to update only differences of filter_hash */
1896 in_old
= !!ftrace_lookup_ip(old_hash
, rec
->ip
);
1897 in_new
= !!ftrace_lookup_ip(new_hash
, rec
->ip
);
1898 if (in_old
== in_new
)
1902 /* New entries must ensure no others are using it */
1903 if (rec
->flags
& FTRACE_FL_IPMODIFY
)
1905 rec
->flags
|= FTRACE_FL_IPMODIFY
;
1906 } else /* Removed entry */
1907 rec
->flags
&= ~FTRACE_FL_IPMODIFY
;
1908 } while_for_each_ftrace_rec();
1915 /* Roll back what we did above */
1916 do_for_each_ftrace_rec(pg
, rec
) {
1918 if (rec
->flags
& FTRACE_FL_DISABLED
)
1924 in_old
= !!ftrace_lookup_ip(old_hash
, rec
->ip
);
1925 in_new
= !!ftrace_lookup_ip(new_hash
, rec
->ip
);
1926 if (in_old
== in_new
)
1930 rec
->flags
&= ~FTRACE_FL_IPMODIFY
;
1932 rec
->flags
|= FTRACE_FL_IPMODIFY
;
1933 } while_for_each_ftrace_rec();
1939 static int ftrace_hash_ipmodify_enable(struct ftrace_ops
*ops
)
1941 struct ftrace_hash
*hash
= ops
->func_hash
->filter_hash
;
1943 if (ftrace_hash_empty(hash
))
1946 return __ftrace_hash_update_ipmodify(ops
, EMPTY_HASH
, hash
);
1949 /* Disabling always succeeds */
1950 static void ftrace_hash_ipmodify_disable(struct ftrace_ops
*ops
)
1952 struct ftrace_hash
*hash
= ops
->func_hash
->filter_hash
;
1954 if (ftrace_hash_empty(hash
))
1957 __ftrace_hash_update_ipmodify(ops
, hash
, EMPTY_HASH
);
1960 static int ftrace_hash_ipmodify_update(struct ftrace_ops
*ops
,
1961 struct ftrace_hash
*new_hash
)
1963 struct ftrace_hash
*old_hash
= ops
->func_hash
->filter_hash
;
1965 if (ftrace_hash_empty(old_hash
))
1968 if (ftrace_hash_empty(new_hash
))
1971 return __ftrace_hash_update_ipmodify(ops
, old_hash
, new_hash
);
1974 static void print_ip_ins(const char *fmt
, const unsigned char *p
)
1978 printk(KERN_CONT
"%s", fmt
);
1980 for (i
= 0; i
< MCOUNT_INSN_SIZE
; i
++)
1981 printk(KERN_CONT
"%s%02x", i
? ":" : "", p
[i
]);
1984 enum ftrace_bug_type ftrace_bug_type
;
1985 const void *ftrace_expected
;
1987 static void print_bug_type(void)
1989 switch (ftrace_bug_type
) {
1990 case FTRACE_BUG_UNKNOWN
:
1992 case FTRACE_BUG_INIT
:
1993 pr_info("Initializing ftrace call sites\n");
1995 case FTRACE_BUG_NOP
:
1996 pr_info("Setting ftrace call site to NOP\n");
1998 case FTRACE_BUG_CALL
:
1999 pr_info("Setting ftrace call site to call ftrace function\n");
2001 case FTRACE_BUG_UPDATE
:
2002 pr_info("Updating ftrace call site to call a different ftrace function\n");
2008 * ftrace_bug - report and shutdown function tracer
2009 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2010 * @rec: The record that failed
2012 * The arch code that enables or disables the function tracing
2013 * can call ftrace_bug() when it has detected a problem in
2014 * modifying the code. @failed should be one of either:
2015 * EFAULT - if the problem happens on reading the @ip address
2016 * EINVAL - if what is read at @ip is not what was expected
2017 * EPERM - if the problem happens on writing to the @ip address
2019 void ftrace_bug(int failed
, struct dyn_ftrace
*rec
)
2021 unsigned long ip
= rec
? rec
->ip
: 0;
2025 FTRACE_WARN_ON_ONCE(1);
2026 pr_info("ftrace faulted on modifying ");
2030 FTRACE_WARN_ON_ONCE(1);
2031 pr_info("ftrace failed to modify ");
2033 print_ip_ins(" actual: ", (unsigned char *)ip
);
2035 if (ftrace_expected
) {
2036 print_ip_ins(" expected: ", ftrace_expected
);
2041 FTRACE_WARN_ON_ONCE(1);
2042 pr_info("ftrace faulted on writing ");
2046 FTRACE_WARN_ON_ONCE(1);
2047 pr_info("ftrace faulted on unknown error ");
2052 struct ftrace_ops
*ops
= NULL
;
2054 pr_info("ftrace record flags: %lx\n", rec
->flags
);
2055 pr_cont(" (%ld)%s", ftrace_rec_count(rec
),
2056 rec
->flags
& FTRACE_FL_REGS
? " R" : " ");
2057 if (rec
->flags
& FTRACE_FL_TRAMP_EN
) {
2058 ops
= ftrace_find_tramp_ops_any(rec
);
2061 pr_cont("\ttramp: %pS (%pS)",
2062 (void *)ops
->trampoline
,
2064 ops
= ftrace_find_tramp_ops_next(rec
, ops
);
2067 pr_cont("\ttramp: ERROR!");
2070 ip
= ftrace_get_addr_curr(rec
);
2071 pr_cont("\n expected tramp: %lx\n", ip
);
2075 static int ftrace_check_record(struct dyn_ftrace
*rec
, bool enable
, bool update
)
2077 unsigned long flag
= 0UL;
2079 ftrace_bug_type
= FTRACE_BUG_UNKNOWN
;
2081 if (rec
->flags
& FTRACE_FL_DISABLED
)
2082 return FTRACE_UPDATE_IGNORE
;
2085 * If we are updating calls:
2087 * If the record has a ref count, then we need to enable it
2088 * because someone is using it.
2090 * Otherwise we make sure its disabled.
2092 * If we are disabling calls, then disable all records that
2095 if (enable
&& ftrace_rec_count(rec
))
2096 flag
= FTRACE_FL_ENABLED
;
2099 * If enabling and the REGS flag does not match the REGS_EN, or
2100 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2101 * this record. Set flags to fail the compare against ENABLED.
2102 * Same for direct calls.
2105 if (!(rec
->flags
& FTRACE_FL_REGS
) !=
2106 !(rec
->flags
& FTRACE_FL_REGS_EN
))
2107 flag
|= FTRACE_FL_REGS
;
2109 if (!(rec
->flags
& FTRACE_FL_TRAMP
) !=
2110 !(rec
->flags
& FTRACE_FL_TRAMP_EN
))
2111 flag
|= FTRACE_FL_TRAMP
;
2114 * Direct calls are special, as count matters.
2115 * We must test the record for direct, if the
2116 * DIRECT and DIRECT_EN do not match, but only
2117 * if the count is 1. That's because, if the
2118 * count is something other than one, we do not
2119 * want the direct enabled (it will be done via the
2120 * direct helper). But if DIRECT_EN is set, and
2121 * the count is not one, we need to clear it.
2123 if (ftrace_rec_count(rec
) == 1) {
2124 if (!(rec
->flags
& FTRACE_FL_DIRECT
) !=
2125 !(rec
->flags
& FTRACE_FL_DIRECT_EN
))
2126 flag
|= FTRACE_FL_DIRECT
;
2127 } else if (rec
->flags
& FTRACE_FL_DIRECT_EN
) {
2128 flag
|= FTRACE_FL_DIRECT
;
2132 /* If the state of this record hasn't changed, then do nothing */
2133 if ((rec
->flags
& FTRACE_FL_ENABLED
) == flag
)
2134 return FTRACE_UPDATE_IGNORE
;
2137 /* Save off if rec is being enabled (for return value) */
2138 flag
^= rec
->flags
& FTRACE_FL_ENABLED
;
2141 rec
->flags
|= FTRACE_FL_ENABLED
;
2142 if (flag
& FTRACE_FL_REGS
) {
2143 if (rec
->flags
& FTRACE_FL_REGS
)
2144 rec
->flags
|= FTRACE_FL_REGS_EN
;
2146 rec
->flags
&= ~FTRACE_FL_REGS_EN
;
2148 if (flag
& FTRACE_FL_TRAMP
) {
2149 if (rec
->flags
& FTRACE_FL_TRAMP
)
2150 rec
->flags
|= FTRACE_FL_TRAMP_EN
;
2152 rec
->flags
&= ~FTRACE_FL_TRAMP_EN
;
2154 if (flag
& FTRACE_FL_DIRECT
) {
2156 * If there's only one user (direct_ops helper)
2157 * then we can call the direct function
2158 * directly (no ftrace trampoline).
2160 if (ftrace_rec_count(rec
) == 1) {
2161 if (rec
->flags
& FTRACE_FL_DIRECT
)
2162 rec
->flags
|= FTRACE_FL_DIRECT_EN
;
2164 rec
->flags
&= ~FTRACE_FL_DIRECT_EN
;
2167 * Can only call directly if there's
2168 * only one callback to the function.
2170 rec
->flags
&= ~FTRACE_FL_DIRECT_EN
;
2176 * If this record is being updated from a nop, then
2177 * return UPDATE_MAKE_CALL.
2179 * return UPDATE_MODIFY_CALL to tell the caller to convert
2180 * from the save regs, to a non-save regs function or
2181 * vice versa, or from a trampoline call.
2183 if (flag
& FTRACE_FL_ENABLED
) {
2184 ftrace_bug_type
= FTRACE_BUG_CALL
;
2185 return FTRACE_UPDATE_MAKE_CALL
;
2188 ftrace_bug_type
= FTRACE_BUG_UPDATE
;
2189 return FTRACE_UPDATE_MODIFY_CALL
;
2193 /* If there's no more users, clear all flags */
2194 if (!ftrace_rec_count(rec
))
2198 * Just disable the record, but keep the ops TRAMP
2199 * and REGS states. The _EN flags must be disabled though.
2201 rec
->flags
&= ~(FTRACE_FL_ENABLED
| FTRACE_FL_TRAMP_EN
|
2202 FTRACE_FL_REGS_EN
| FTRACE_FL_DIRECT_EN
);
2205 ftrace_bug_type
= FTRACE_BUG_NOP
;
2206 return FTRACE_UPDATE_MAKE_NOP
;
2210 * ftrace_update_record, set a record that now is tracing or not
2211 * @rec: the record to update
2212 * @enable: set to true if the record is tracing, false to force disable
2214 * The records that represent all functions that can be traced need
2215 * to be updated when tracing has been enabled.
2217 int ftrace_update_record(struct dyn_ftrace
*rec
, bool enable
)
2219 return ftrace_check_record(rec
, enable
, true);
2223 * ftrace_test_record, check if the record has been enabled or not
2224 * @rec: the record to test
2225 * @enable: set to true to check if enabled, false if it is disabled
2227 * The arch code may need to test if a record is already set to
2228 * tracing to determine how to modify the function code that it
2231 int ftrace_test_record(struct dyn_ftrace
*rec
, bool enable
)
2233 return ftrace_check_record(rec
, enable
, false);
2236 static struct ftrace_ops
*
2237 ftrace_find_tramp_ops_any(struct dyn_ftrace
*rec
)
2239 struct ftrace_ops
*op
;
2240 unsigned long ip
= rec
->ip
;
2242 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
2244 if (!op
->trampoline
)
2247 if (hash_contains_ip(ip
, op
->func_hash
))
2249 } while_for_each_ftrace_op(op
);
2254 static struct ftrace_ops
*
2255 ftrace_find_tramp_ops_next(struct dyn_ftrace
*rec
,
2256 struct ftrace_ops
*op
)
2258 unsigned long ip
= rec
->ip
;
2260 while_for_each_ftrace_op(op
) {
2262 if (!op
->trampoline
)
2265 if (hash_contains_ip(ip
, op
->func_hash
))
2272 static struct ftrace_ops
*
2273 ftrace_find_tramp_ops_curr(struct dyn_ftrace
*rec
)
2275 struct ftrace_ops
*op
;
2276 unsigned long ip
= rec
->ip
;
2279 * Need to check removed ops first.
2280 * If they are being removed, and this rec has a tramp,
2281 * and this rec is in the ops list, then it would be the
2282 * one with the tramp.
2285 if (hash_contains_ip(ip
, &removed_ops
->old_hash
))
2290 * Need to find the current trampoline for a rec.
2291 * Now, a trampoline is only attached to a rec if there
2292 * was a single 'ops' attached to it. But this can be called
2293 * when we are adding another op to the rec or removing the
2294 * current one. Thus, if the op is being added, we can
2295 * ignore it because it hasn't attached itself to the rec
2298 * If an ops is being modified (hooking to different functions)
2299 * then we don't care about the new functions that are being
2300 * added, just the old ones (that are probably being removed).
2302 * If we are adding an ops to a function that already is using
2303 * a trampoline, it needs to be removed (trampolines are only
2304 * for single ops connected), then an ops that is not being
2305 * modified also needs to be checked.
2307 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
2309 if (!op
->trampoline
)
2313 * If the ops is being added, it hasn't gotten to
2314 * the point to be removed from this tree yet.
2316 if (op
->flags
& FTRACE_OPS_FL_ADDING
)
2321 * If the ops is being modified and is in the old
2322 * hash, then it is probably being removed from this
2325 if ((op
->flags
& FTRACE_OPS_FL_MODIFYING
) &&
2326 hash_contains_ip(ip
, &op
->old_hash
))
2329 * If the ops is not being added or modified, and it's
2330 * in its normal filter hash, then this must be the one
2333 if (!(op
->flags
& FTRACE_OPS_FL_MODIFYING
) &&
2334 hash_contains_ip(ip
, op
->func_hash
))
2337 } while_for_each_ftrace_op(op
);
2342 static struct ftrace_ops
*
2343 ftrace_find_tramp_ops_new(struct dyn_ftrace
*rec
)
2345 struct ftrace_ops
*op
;
2346 unsigned long ip
= rec
->ip
;
2348 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
2349 /* pass rec in as regs to have non-NULL val */
2350 if (hash_contains_ip(ip
, op
->func_hash
))
2352 } while_for_each_ftrace_op(op
);
2357 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
2358 /* Protected by rcu_tasks for reading, and direct_mutex for writing */
2359 static struct ftrace_hash
*direct_functions
= EMPTY_HASH
;
2360 static DEFINE_MUTEX(direct_mutex
);
2361 int ftrace_direct_func_count
;
2364 * Search the direct_functions hash to see if the given instruction pointer
2365 * has a direct caller attached to it.
2367 static unsigned long find_rec_direct(unsigned long ip
)
2369 struct ftrace_func_entry
*entry
;
2371 entry
= __ftrace_lookup_ip(direct_functions
, ip
);
2375 return entry
->direct
;
2378 static void call_direct_funcs(unsigned long ip
, unsigned long pip
,
2379 struct ftrace_ops
*ops
, struct pt_regs
*regs
)
2383 addr
= find_rec_direct(ip
);
2387 arch_ftrace_set_direct_caller(regs
, addr
);
2390 struct ftrace_ops direct_ops
= {
2391 .func
= call_direct_funcs
,
2392 .flags
= FTRACE_OPS_FL_IPMODIFY
| FTRACE_OPS_FL_RECURSION_SAFE
2393 | FTRACE_OPS_FL_DIRECT
| FTRACE_OPS_FL_SAVE_REGS
2394 | FTRACE_OPS_FL_PERMANENT
,
2397 static inline unsigned long find_rec_direct(unsigned long ip
)
2401 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
2404 * ftrace_get_addr_new - Get the call address to set to
2405 * @rec: The ftrace record descriptor
2407 * If the record has the FTRACE_FL_REGS set, that means that it
2408 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2409 * is not not set, then it wants to convert to the normal callback.
2411 * Returns the address of the trampoline to set to
2413 unsigned long ftrace_get_addr_new(struct dyn_ftrace
*rec
)
2415 struct ftrace_ops
*ops
;
2418 if ((rec
->flags
& FTRACE_FL_DIRECT
) &&
2419 (ftrace_rec_count(rec
) == 1)) {
2420 addr
= find_rec_direct(rec
->ip
);
2426 /* Trampolines take precedence over regs */
2427 if (rec
->flags
& FTRACE_FL_TRAMP
) {
2428 ops
= ftrace_find_tramp_ops_new(rec
);
2429 if (FTRACE_WARN_ON(!ops
|| !ops
->trampoline
)) {
2430 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2431 (void *)rec
->ip
, (void *)rec
->ip
, rec
->flags
);
2432 /* Ftrace is shutting down, return anything */
2433 return (unsigned long)FTRACE_ADDR
;
2435 return ops
->trampoline
;
2438 if (rec
->flags
& FTRACE_FL_REGS
)
2439 return (unsigned long)FTRACE_REGS_ADDR
;
2441 return (unsigned long)FTRACE_ADDR
;
2445 * ftrace_get_addr_curr - Get the call address that is already there
2446 * @rec: The ftrace record descriptor
2448 * The FTRACE_FL_REGS_EN is set when the record already points to
2449 * a function that saves all the regs. Basically the '_EN' version
2450 * represents the current state of the function.
2452 * Returns the address of the trampoline that is currently being called
2454 unsigned long ftrace_get_addr_curr(struct dyn_ftrace
*rec
)
2456 struct ftrace_ops
*ops
;
2459 /* Direct calls take precedence over trampolines */
2460 if (rec
->flags
& FTRACE_FL_DIRECT_EN
) {
2461 addr
= find_rec_direct(rec
->ip
);
2467 /* Trampolines take precedence over regs */
2468 if (rec
->flags
& FTRACE_FL_TRAMP_EN
) {
2469 ops
= ftrace_find_tramp_ops_curr(rec
);
2470 if (FTRACE_WARN_ON(!ops
)) {
2471 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2472 (void *)rec
->ip
, (void *)rec
->ip
);
2473 /* Ftrace is shutting down, return anything */
2474 return (unsigned long)FTRACE_ADDR
;
2476 return ops
->trampoline
;
2479 if (rec
->flags
& FTRACE_FL_REGS_EN
)
2480 return (unsigned long)FTRACE_REGS_ADDR
;
2482 return (unsigned long)FTRACE_ADDR
;
2486 __ftrace_replace_code(struct dyn_ftrace
*rec
, bool enable
)
2488 unsigned long ftrace_old_addr
;
2489 unsigned long ftrace_addr
;
2492 ftrace_addr
= ftrace_get_addr_new(rec
);
2494 /* This needs to be done before we call ftrace_update_record */
2495 ftrace_old_addr
= ftrace_get_addr_curr(rec
);
2497 ret
= ftrace_update_record(rec
, enable
);
2499 ftrace_bug_type
= FTRACE_BUG_UNKNOWN
;
2502 case FTRACE_UPDATE_IGNORE
:
2505 case FTRACE_UPDATE_MAKE_CALL
:
2506 ftrace_bug_type
= FTRACE_BUG_CALL
;
2507 return ftrace_make_call(rec
, ftrace_addr
);
2509 case FTRACE_UPDATE_MAKE_NOP
:
2510 ftrace_bug_type
= FTRACE_BUG_NOP
;
2511 return ftrace_make_nop(NULL
, rec
, ftrace_old_addr
);
2513 case FTRACE_UPDATE_MODIFY_CALL
:
2514 ftrace_bug_type
= FTRACE_BUG_UPDATE
;
2515 return ftrace_modify_call(rec
, ftrace_old_addr
, ftrace_addr
);
2518 return -1; /* unknown ftrace bug */
2521 void __weak
ftrace_replace_code(int mod_flags
)
2523 struct dyn_ftrace
*rec
;
2524 struct ftrace_page
*pg
;
2525 bool enable
= mod_flags
& FTRACE_MODIFY_ENABLE_FL
;
2526 int schedulable
= mod_flags
& FTRACE_MODIFY_MAY_SLEEP_FL
;
2529 if (unlikely(ftrace_disabled
))
2532 do_for_each_ftrace_rec(pg
, rec
) {
2534 if (rec
->flags
& FTRACE_FL_DISABLED
)
2537 failed
= __ftrace_replace_code(rec
, enable
);
2539 ftrace_bug(failed
, rec
);
2540 /* Stop processing */
2545 } while_for_each_ftrace_rec();
2548 struct ftrace_rec_iter
{
2549 struct ftrace_page
*pg
;
2554 * ftrace_rec_iter_start, start up iterating over traced functions
2556 * Returns an iterator handle that is used to iterate over all
2557 * the records that represent address locations where functions
2560 * May return NULL if no records are available.
2562 struct ftrace_rec_iter
*ftrace_rec_iter_start(void)
2565 * We only use a single iterator.
2566 * Protected by the ftrace_lock mutex.
2568 static struct ftrace_rec_iter ftrace_rec_iter
;
2569 struct ftrace_rec_iter
*iter
= &ftrace_rec_iter
;
2571 iter
->pg
= ftrace_pages_start
;
2574 /* Could have empty pages */
2575 while (iter
->pg
&& !iter
->pg
->index
)
2576 iter
->pg
= iter
->pg
->next
;
2585 * ftrace_rec_iter_next, get the next record to process.
2586 * @iter: The handle to the iterator.
2588 * Returns the next iterator after the given iterator @iter.
2590 struct ftrace_rec_iter
*ftrace_rec_iter_next(struct ftrace_rec_iter
*iter
)
2594 if (iter
->index
>= iter
->pg
->index
) {
2595 iter
->pg
= iter
->pg
->next
;
2598 /* Could have empty pages */
2599 while (iter
->pg
&& !iter
->pg
->index
)
2600 iter
->pg
= iter
->pg
->next
;
2610 * ftrace_rec_iter_record, get the record at the iterator location
2611 * @iter: The current iterator location
2613 * Returns the record that the current @iter is at.
2615 struct dyn_ftrace
*ftrace_rec_iter_record(struct ftrace_rec_iter
*iter
)
2617 return &iter
->pg
->records
[iter
->index
];
2621 ftrace_nop_initialize(struct module
*mod
, struct dyn_ftrace
*rec
)
2625 if (unlikely(ftrace_disabled
))
2628 ret
= ftrace_init_nop(mod
, rec
);
2630 ftrace_bug_type
= FTRACE_BUG_INIT
;
2631 ftrace_bug(ret
, rec
);
2638 * archs can override this function if they must do something
2639 * before the modifying code is performed.
2641 int __weak
ftrace_arch_code_modify_prepare(void)
2647 * archs can override this function if they must do something
2648 * after the modifying code is performed.
2650 int __weak
ftrace_arch_code_modify_post_process(void)
2655 void ftrace_modify_all_code(int command
)
2657 int update
= command
& FTRACE_UPDATE_TRACE_FUNC
;
2661 if (command
& FTRACE_MAY_SLEEP
)
2662 mod_flags
= FTRACE_MODIFY_MAY_SLEEP_FL
;
2665 * If the ftrace_caller calls a ftrace_ops func directly,
2666 * we need to make sure that it only traces functions it
2667 * expects to trace. When doing the switch of functions,
2668 * we need to update to the ftrace_ops_list_func first
2669 * before the transition between old and new calls are set,
2670 * as the ftrace_ops_list_func will check the ops hashes
2671 * to make sure the ops are having the right functions
2675 err
= ftrace_update_ftrace_func(ftrace_ops_list_func
);
2676 if (FTRACE_WARN_ON(err
))
2680 if (command
& FTRACE_UPDATE_CALLS
)
2681 ftrace_replace_code(mod_flags
| FTRACE_MODIFY_ENABLE_FL
);
2682 else if (command
& FTRACE_DISABLE_CALLS
)
2683 ftrace_replace_code(mod_flags
);
2685 if (update
&& ftrace_trace_function
!= ftrace_ops_list_func
) {
2686 function_trace_op
= set_function_trace_op
;
2688 /* If irqs are disabled, we are in stop machine */
2689 if (!irqs_disabled())
2690 smp_call_function(ftrace_sync_ipi
, NULL
, 1);
2691 err
= ftrace_update_ftrace_func(ftrace_trace_function
);
2692 if (FTRACE_WARN_ON(err
))
2696 if (command
& FTRACE_START_FUNC_RET
)
2697 err
= ftrace_enable_ftrace_graph_caller();
2698 else if (command
& FTRACE_STOP_FUNC_RET
)
2699 err
= ftrace_disable_ftrace_graph_caller();
2700 FTRACE_WARN_ON(err
);
2703 static int __ftrace_modify_code(void *data
)
2705 int *command
= data
;
2707 ftrace_modify_all_code(*command
);
2713 * ftrace_run_stop_machine, go back to the stop machine method
2714 * @command: The command to tell ftrace what to do
2716 * If an arch needs to fall back to the stop machine method, the
2717 * it can call this function.
2719 void ftrace_run_stop_machine(int command
)
2721 stop_machine(__ftrace_modify_code
, &command
, NULL
);
2725 * arch_ftrace_update_code, modify the code to trace or not trace
2726 * @command: The command that needs to be done
2728 * Archs can override this function if it does not need to
2729 * run stop_machine() to modify code.
2731 void __weak
arch_ftrace_update_code(int command
)
2733 ftrace_run_stop_machine(command
);
2736 static void ftrace_run_update_code(int command
)
2740 ret
= ftrace_arch_code_modify_prepare();
2741 FTRACE_WARN_ON(ret
);
2746 * By default we use stop_machine() to modify the code.
2747 * But archs can do what ever they want as long as it
2748 * is safe. The stop_machine() is the safest, but also
2749 * produces the most overhead.
2751 arch_ftrace_update_code(command
);
2753 ret
= ftrace_arch_code_modify_post_process();
2754 FTRACE_WARN_ON(ret
);
2757 static void ftrace_run_modify_code(struct ftrace_ops
*ops
, int command
,
2758 struct ftrace_ops_hash
*old_hash
)
2760 ops
->flags
|= FTRACE_OPS_FL_MODIFYING
;
2761 ops
->old_hash
.filter_hash
= old_hash
->filter_hash
;
2762 ops
->old_hash
.notrace_hash
= old_hash
->notrace_hash
;
2763 ftrace_run_update_code(command
);
2764 ops
->old_hash
.filter_hash
= NULL
;
2765 ops
->old_hash
.notrace_hash
= NULL
;
2766 ops
->flags
&= ~FTRACE_OPS_FL_MODIFYING
;
2769 static ftrace_func_t saved_ftrace_func
;
2770 static int ftrace_start_up
;
2772 void __weak
arch_ftrace_trampoline_free(struct ftrace_ops
*ops
)
2776 static void ftrace_startup_enable(int command
)
2778 if (saved_ftrace_func
!= ftrace_trace_function
) {
2779 saved_ftrace_func
= ftrace_trace_function
;
2780 command
|= FTRACE_UPDATE_TRACE_FUNC
;
2783 if (!command
|| !ftrace_enabled
)
2786 ftrace_run_update_code(command
);
2789 static void ftrace_startup_all(int command
)
2791 update_all_ops
= true;
2792 ftrace_startup_enable(command
);
2793 update_all_ops
= false;
2796 int ftrace_startup(struct ftrace_ops
*ops
, int command
)
2800 if (unlikely(ftrace_disabled
))
2803 ret
= __register_ftrace_function(ops
);
2810 * Note that ftrace probes uses this to start up
2811 * and modify functions it will probe. But we still
2812 * set the ADDING flag for modification, as probes
2813 * do not have trampolines. If they add them in the
2814 * future, then the probes will need to distinguish
2815 * between adding and updating probes.
2817 ops
->flags
|= FTRACE_OPS_FL_ENABLED
| FTRACE_OPS_FL_ADDING
;
2819 ret
= ftrace_hash_ipmodify_enable(ops
);
2821 /* Rollback registration process */
2822 __unregister_ftrace_function(ops
);
2824 ops
->flags
&= ~FTRACE_OPS_FL_ENABLED
;
2828 if (ftrace_hash_rec_enable(ops
, 1))
2829 command
|= FTRACE_UPDATE_CALLS
;
2831 ftrace_startup_enable(command
);
2833 ops
->flags
&= ~FTRACE_OPS_FL_ADDING
;
2838 int ftrace_shutdown(struct ftrace_ops
*ops
, int command
)
2842 if (unlikely(ftrace_disabled
))
2845 ret
= __unregister_ftrace_function(ops
);
2851 * Just warn in case of unbalance, no need to kill ftrace, it's not
2852 * critical but the ftrace_call callers may be never nopped again after
2853 * further ftrace uses.
2855 WARN_ON_ONCE(ftrace_start_up
< 0);
2857 /* Disabling ipmodify never fails */
2858 ftrace_hash_ipmodify_disable(ops
);
2860 if (ftrace_hash_rec_disable(ops
, 1))
2861 command
|= FTRACE_UPDATE_CALLS
;
2863 ops
->flags
&= ~FTRACE_OPS_FL_ENABLED
;
2865 if (saved_ftrace_func
!= ftrace_trace_function
) {
2866 saved_ftrace_func
= ftrace_trace_function
;
2867 command
|= FTRACE_UPDATE_TRACE_FUNC
;
2870 if (!command
|| !ftrace_enabled
) {
2872 * If these are dynamic or per_cpu ops, they still
2873 * need their data freed. Since, function tracing is
2874 * not currently active, we can just free them
2875 * without synchronizing all CPUs.
2877 if (ops
->flags
& FTRACE_OPS_FL_DYNAMIC
)
2884 * If the ops uses a trampoline, then it needs to be
2885 * tested first on update.
2887 ops
->flags
|= FTRACE_OPS_FL_REMOVING
;
2890 /* The trampoline logic checks the old hashes */
2891 ops
->old_hash
.filter_hash
= ops
->func_hash
->filter_hash
;
2892 ops
->old_hash
.notrace_hash
= ops
->func_hash
->notrace_hash
;
2894 ftrace_run_update_code(command
);
2897 * If there's no more ops registered with ftrace, run a
2898 * sanity check to make sure all rec flags are cleared.
2900 if (rcu_dereference_protected(ftrace_ops_list
,
2901 lockdep_is_held(&ftrace_lock
)) == &ftrace_list_end
) {
2902 struct ftrace_page
*pg
;
2903 struct dyn_ftrace
*rec
;
2905 do_for_each_ftrace_rec(pg
, rec
) {
2906 if (FTRACE_WARN_ON_ONCE(rec
->flags
& ~FTRACE_FL_DISABLED
))
2907 pr_warn(" %pS flags:%lx\n",
2908 (void *)rec
->ip
, rec
->flags
);
2909 } while_for_each_ftrace_rec();
2912 ops
->old_hash
.filter_hash
= NULL
;
2913 ops
->old_hash
.notrace_hash
= NULL
;
2916 ops
->flags
&= ~FTRACE_OPS_FL_REMOVING
;
2919 * Dynamic ops may be freed, we must make sure that all
2920 * callers are done before leaving this function.
2921 * The same goes for freeing the per_cpu data of the per_cpu
2924 if (ops
->flags
& FTRACE_OPS_FL_DYNAMIC
) {
2926 * We need to do a hard force of sched synchronization.
2927 * This is because we use preempt_disable() to do RCU, but
2928 * the function tracers can be called where RCU is not watching
2929 * (like before user_exit()). We can not rely on the RCU
2930 * infrastructure to do the synchronization, thus we must do it
2933 schedule_on_each_cpu(ftrace_sync
);
2936 * When the kernel is preeptive, tasks can be preempted
2937 * while on a ftrace trampoline. Just scheduling a task on
2938 * a CPU is not good enough to flush them. Calling
2939 * synchornize_rcu_tasks() will wait for those tasks to
2940 * execute and either schedule voluntarily or enter user space.
2942 if (IS_ENABLED(CONFIG_PREEMPTION
))
2943 synchronize_rcu_tasks();
2946 arch_ftrace_trampoline_free(ops
);
2952 static void ftrace_startup_sysctl(void)
2956 if (unlikely(ftrace_disabled
))
2959 /* Force update next time */
2960 saved_ftrace_func
= NULL
;
2961 /* ftrace_start_up is true if we want ftrace running */
2962 if (ftrace_start_up
) {
2963 command
= FTRACE_UPDATE_CALLS
;
2964 if (ftrace_graph_active
)
2965 command
|= FTRACE_START_FUNC_RET
;
2966 ftrace_startup_enable(command
);
2970 static void ftrace_shutdown_sysctl(void)
2974 if (unlikely(ftrace_disabled
))
2977 /* ftrace_start_up is true if ftrace is running */
2978 if (ftrace_start_up
) {
2979 command
= FTRACE_DISABLE_CALLS
;
2980 if (ftrace_graph_active
)
2981 command
|= FTRACE_STOP_FUNC_RET
;
2982 ftrace_run_update_code(command
);
2986 static u64 ftrace_update_time
;
2987 unsigned long ftrace_update_tot_cnt
;
2988 unsigned long ftrace_number_of_pages
;
2989 unsigned long ftrace_number_of_groups
;
2991 static inline int ops_traces_mod(struct ftrace_ops
*ops
)
2994 * Filter_hash being empty will default to trace module.
2995 * But notrace hash requires a test of individual module functions.
2997 return ftrace_hash_empty(ops
->func_hash
->filter_hash
) &&
2998 ftrace_hash_empty(ops
->func_hash
->notrace_hash
);
3002 * Check if the current ops references the record.
3004 * If the ops traces all functions, then it was already accounted for.
3005 * If the ops does not trace the current record function, skip it.
3006 * If the ops ignores the function via notrace filter, skip it.
3009 ops_references_rec(struct ftrace_ops
*ops
, struct dyn_ftrace
*rec
)
3011 /* If ops isn't enabled, ignore it */
3012 if (!(ops
->flags
& FTRACE_OPS_FL_ENABLED
))
3015 /* If ops traces all then it includes this function */
3016 if (ops_traces_mod(ops
))
3019 /* The function must be in the filter */
3020 if (!ftrace_hash_empty(ops
->func_hash
->filter_hash
) &&
3021 !__ftrace_lookup_ip(ops
->func_hash
->filter_hash
, rec
->ip
))
3024 /* If in notrace hash, we ignore it too */
3025 if (ftrace_lookup_ip(ops
->func_hash
->notrace_hash
, rec
->ip
))
3031 static int ftrace_update_code(struct module
*mod
, struct ftrace_page
*new_pgs
)
3033 struct ftrace_page
*pg
;
3034 struct dyn_ftrace
*p
;
3036 unsigned long update_cnt
= 0;
3037 unsigned long rec_flags
= 0;
3040 start
= ftrace_now(raw_smp_processor_id());
3043 * When a module is loaded, this function is called to convert
3044 * the calls to mcount in its text to nops, and also to create
3045 * an entry in the ftrace data. Now, if ftrace is activated
3046 * after this call, but before the module sets its text to
3047 * read-only, the modification of enabling ftrace can fail if
3048 * the read-only is done while ftrace is converting the calls.
3049 * To prevent this, the module's records are set as disabled
3050 * and will be enabled after the call to set the module's text
3054 rec_flags
|= FTRACE_FL_DISABLED
;
3056 for (pg
= new_pgs
; pg
; pg
= pg
->next
) {
3058 for (i
= 0; i
< pg
->index
; i
++) {
3060 /* If something went wrong, bail without enabling anything */
3061 if (unlikely(ftrace_disabled
))
3064 p
= &pg
->records
[i
];
3065 p
->flags
= rec_flags
;
3068 * Do the initial record conversion from mcount jump
3069 * to the NOP instructions.
3071 if (!__is_defined(CC_USING_NOP_MCOUNT
) &&
3072 !ftrace_nop_initialize(mod
, p
))
3079 stop
= ftrace_now(raw_smp_processor_id());
3080 ftrace_update_time
= stop
- start
;
3081 ftrace_update_tot_cnt
+= update_cnt
;
3086 static int ftrace_allocate_records(struct ftrace_page
*pg
, int count
)
3091 if (WARN_ON(!count
))
3094 order
= get_count_order(DIV_ROUND_UP(count
, ENTRIES_PER_PAGE
));
3097 * We want to fill as much as possible. No more than a page
3100 while ((PAGE_SIZE
<< order
) / ENTRY_SIZE
>= count
+ ENTRIES_PER_PAGE
)
3104 pg
->records
= (void *)__get_free_pages(GFP_KERNEL
| __GFP_ZERO
, order
);
3107 /* if we can't allocate this size, try something smaller */
3114 ftrace_number_of_pages
+= 1 << order
;
3115 ftrace_number_of_groups
++;
3117 cnt
= (PAGE_SIZE
<< order
) / ENTRY_SIZE
;
3126 static struct ftrace_page
*
3127 ftrace_allocate_pages(unsigned long num_to_init
)
3129 struct ftrace_page
*start_pg
;
3130 struct ftrace_page
*pg
;
3137 start_pg
= pg
= kzalloc(sizeof(*pg
), GFP_KERNEL
);
3142 * Try to allocate as much as possible in one continues
3143 * location that fills in all of the space. We want to
3144 * waste as little space as possible.
3147 cnt
= ftrace_allocate_records(pg
, num_to_init
);
3155 pg
->next
= kzalloc(sizeof(*pg
), GFP_KERNEL
);
3167 order
= get_count_order(pg
->size
/ ENTRIES_PER_PAGE
);
3168 free_pages((unsigned long)pg
->records
, order
);
3169 start_pg
= pg
->next
;
3172 ftrace_number_of_pages
-= 1 << order
;
3173 ftrace_number_of_groups
--;
3175 pr_info("ftrace: FAILED to allocate memory for functions\n");
3179 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3181 struct ftrace_iterator
{
3185 struct ftrace_page
*pg
;
3186 struct dyn_ftrace
*func
;
3187 struct ftrace_func_probe
*probe
;
3188 struct ftrace_func_entry
*probe_entry
;
3189 struct trace_parser parser
;
3190 struct ftrace_hash
*hash
;
3191 struct ftrace_ops
*ops
;
3192 struct trace_array
*tr
;
3193 struct list_head
*mod_list
;
3200 t_probe_next(struct seq_file
*m
, loff_t
*pos
)
3202 struct ftrace_iterator
*iter
= m
->private;
3203 struct trace_array
*tr
= iter
->ops
->private;
3204 struct list_head
*func_probes
;
3205 struct ftrace_hash
*hash
;
3206 struct list_head
*next
;
3207 struct hlist_node
*hnd
= NULL
;
3208 struct hlist_head
*hhd
;
3217 func_probes
= &tr
->func_probes
;
3218 if (list_empty(func_probes
))
3222 next
= func_probes
->next
;
3223 iter
->probe
= list_entry(next
, struct ftrace_func_probe
, list
);
3226 if (iter
->probe_entry
)
3227 hnd
= &iter
->probe_entry
->hlist
;
3229 hash
= iter
->probe
->ops
.func_hash
->filter_hash
;
3232 * A probe being registered may temporarily have an empty hash
3233 * and it's at the end of the func_probes list.
3235 if (!hash
|| hash
== EMPTY_HASH
)
3238 size
= 1 << hash
->size_bits
;
3241 if (iter
->pidx
>= size
) {
3242 if (iter
->probe
->list
.next
== func_probes
)
3244 next
= iter
->probe
->list
.next
;
3245 iter
->probe
= list_entry(next
, struct ftrace_func_probe
, list
);
3246 hash
= iter
->probe
->ops
.func_hash
->filter_hash
;
3247 size
= 1 << hash
->size_bits
;
3251 hhd
= &hash
->buckets
[iter
->pidx
];
3253 if (hlist_empty(hhd
)) {
3269 if (WARN_ON_ONCE(!hnd
))
3272 iter
->probe_entry
= hlist_entry(hnd
, struct ftrace_func_entry
, hlist
);
3277 static void *t_probe_start(struct seq_file
*m
, loff_t
*pos
)
3279 struct ftrace_iterator
*iter
= m
->private;
3283 if (!(iter
->flags
& FTRACE_ITER_DO_PROBES
))
3286 if (iter
->mod_pos
> *pos
)
3290 iter
->probe_entry
= NULL
;
3292 for (l
= 0; l
<= (*pos
- iter
->mod_pos
); ) {
3293 p
= t_probe_next(m
, &l
);
3300 /* Only set this if we have an item */
3301 iter
->flags
|= FTRACE_ITER_PROBE
;
3307 t_probe_show(struct seq_file
*m
, struct ftrace_iterator
*iter
)
3309 struct ftrace_func_entry
*probe_entry
;
3310 struct ftrace_probe_ops
*probe_ops
;
3311 struct ftrace_func_probe
*probe
;
3313 probe
= iter
->probe
;
3314 probe_entry
= iter
->probe_entry
;
3316 if (WARN_ON_ONCE(!probe
|| !probe_entry
))
3319 probe_ops
= probe
->probe_ops
;
3321 if (probe_ops
->print
)
3322 return probe_ops
->print(m
, probe_entry
->ip
, probe_ops
, probe
->data
);
3324 seq_printf(m
, "%ps:%ps\n", (void *)probe_entry
->ip
,
3325 (void *)probe_ops
->func
);
3331 t_mod_next(struct seq_file
*m
, loff_t
*pos
)
3333 struct ftrace_iterator
*iter
= m
->private;
3334 struct trace_array
*tr
= iter
->tr
;
3339 iter
->mod_list
= iter
->mod_list
->next
;
3341 if (iter
->mod_list
== &tr
->mod_trace
||
3342 iter
->mod_list
== &tr
->mod_notrace
) {
3343 iter
->flags
&= ~FTRACE_ITER_MOD
;
3347 iter
->mod_pos
= *pos
;
3352 static void *t_mod_start(struct seq_file
*m
, loff_t
*pos
)
3354 struct ftrace_iterator
*iter
= m
->private;
3358 if (iter
->func_pos
> *pos
)
3361 iter
->mod_pos
= iter
->func_pos
;
3363 /* probes are only available if tr is set */
3367 for (l
= 0; l
<= (*pos
- iter
->func_pos
); ) {
3368 p
= t_mod_next(m
, &l
);
3373 iter
->flags
&= ~FTRACE_ITER_MOD
;
3374 return t_probe_start(m
, pos
);
3377 /* Only set this if we have an item */
3378 iter
->flags
|= FTRACE_ITER_MOD
;
3384 t_mod_show(struct seq_file
*m
, struct ftrace_iterator
*iter
)
3386 struct ftrace_mod_load
*ftrace_mod
;
3387 struct trace_array
*tr
= iter
->tr
;
3389 if (WARN_ON_ONCE(!iter
->mod_list
) ||
3390 iter
->mod_list
== &tr
->mod_trace
||
3391 iter
->mod_list
== &tr
->mod_notrace
)
3394 ftrace_mod
= list_entry(iter
->mod_list
, struct ftrace_mod_load
, list
);
3396 if (ftrace_mod
->func
)
3397 seq_printf(m
, "%s", ftrace_mod
->func
);
3401 seq_printf(m
, ":mod:%s\n", ftrace_mod
->module
);
3407 t_func_next(struct seq_file
*m
, loff_t
*pos
)
3409 struct ftrace_iterator
*iter
= m
->private;
3410 struct dyn_ftrace
*rec
= NULL
;
3415 if (iter
->idx
>= iter
->pg
->index
) {
3416 if (iter
->pg
->next
) {
3417 iter
->pg
= iter
->pg
->next
;
3422 rec
= &iter
->pg
->records
[iter
->idx
++];
3423 if (((iter
->flags
& (FTRACE_ITER_FILTER
| FTRACE_ITER_NOTRACE
)) &&
3424 !ftrace_lookup_ip(iter
->hash
, rec
->ip
)) ||
3426 ((iter
->flags
& FTRACE_ITER_ENABLED
) &&
3427 !(rec
->flags
& FTRACE_FL_ENABLED
))) {
3437 iter
->pos
= iter
->func_pos
= *pos
;
3444 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
3446 struct ftrace_iterator
*iter
= m
->private;
3447 loff_t l
= *pos
; /* t_probe_start() must use original pos */
3450 if (unlikely(ftrace_disabled
))
3453 if (iter
->flags
& FTRACE_ITER_PROBE
)
3454 return t_probe_next(m
, pos
);
3456 if (iter
->flags
& FTRACE_ITER_MOD
)
3457 return t_mod_next(m
, pos
);
3459 if (iter
->flags
& FTRACE_ITER_PRINTALL
) {
3460 /* next must increment pos, and t_probe_start does not */
3462 return t_mod_start(m
, &l
);
3465 ret
= t_func_next(m
, pos
);
3468 return t_mod_start(m
, &l
);
3473 static void reset_iter_read(struct ftrace_iterator
*iter
)
3477 iter
->flags
&= ~(FTRACE_ITER_PRINTALL
| FTRACE_ITER_PROBE
| FTRACE_ITER_MOD
);
3480 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
3482 struct ftrace_iterator
*iter
= m
->private;
3486 mutex_lock(&ftrace_lock
);
3488 if (unlikely(ftrace_disabled
))
3492 * If an lseek was done, then reset and start from beginning.
3494 if (*pos
< iter
->pos
)
3495 reset_iter_read(iter
);
3498 * For set_ftrace_filter reading, if we have the filter
3499 * off, we can short cut and just print out that all
3500 * functions are enabled.
3502 if ((iter
->flags
& (FTRACE_ITER_FILTER
| FTRACE_ITER_NOTRACE
)) &&
3503 ftrace_hash_empty(iter
->hash
)) {
3504 iter
->func_pos
= 1; /* Account for the message */
3506 return t_mod_start(m
, pos
);
3507 iter
->flags
|= FTRACE_ITER_PRINTALL
;
3508 /* reset in case of seek/pread */
3509 iter
->flags
&= ~FTRACE_ITER_PROBE
;
3513 if (iter
->flags
& FTRACE_ITER_MOD
)
3514 return t_mod_start(m
, pos
);
3517 * Unfortunately, we need to restart at ftrace_pages_start
3518 * every time we let go of the ftrace_mutex. This is because
3519 * those pointers can change without the lock.
3521 iter
->pg
= ftrace_pages_start
;
3523 for (l
= 0; l
<= *pos
; ) {
3524 p
= t_func_next(m
, &l
);
3530 return t_mod_start(m
, pos
);
3535 static void t_stop(struct seq_file
*m
, void *p
)
3537 mutex_unlock(&ftrace_lock
);
3541 arch_ftrace_trampoline_func(struct ftrace_ops
*ops
, struct dyn_ftrace
*rec
)
3546 static void add_trampoline_func(struct seq_file
*m
, struct ftrace_ops
*ops
,
3547 struct dyn_ftrace
*rec
)
3551 ptr
= arch_ftrace_trampoline_func(ops
, rec
);
3553 seq_printf(m
, " ->%pS", ptr
);
3556 static int t_show(struct seq_file
*m
, void *v
)
3558 struct ftrace_iterator
*iter
= m
->private;
3559 struct dyn_ftrace
*rec
;
3561 if (iter
->flags
& FTRACE_ITER_PROBE
)
3562 return t_probe_show(m
, iter
);
3564 if (iter
->flags
& FTRACE_ITER_MOD
)
3565 return t_mod_show(m
, iter
);
3567 if (iter
->flags
& FTRACE_ITER_PRINTALL
) {
3568 if (iter
->flags
& FTRACE_ITER_NOTRACE
)
3569 seq_puts(m
, "#### no functions disabled ####\n");
3571 seq_puts(m
, "#### all functions enabled ####\n");
3580 seq_printf(m
, "%ps", (void *)rec
->ip
);
3581 if (iter
->flags
& FTRACE_ITER_ENABLED
) {
3582 struct ftrace_ops
*ops
;
3584 seq_printf(m
, " (%ld)%s%s%s",
3585 ftrace_rec_count(rec
),
3586 rec
->flags
& FTRACE_FL_REGS
? " R" : " ",
3587 rec
->flags
& FTRACE_FL_IPMODIFY
? " I" : " ",
3588 rec
->flags
& FTRACE_FL_DIRECT
? " D" : " ");
3589 if (rec
->flags
& FTRACE_FL_TRAMP_EN
) {
3590 ops
= ftrace_find_tramp_ops_any(rec
);
3593 seq_printf(m
, "\ttramp: %pS (%pS)",
3594 (void *)ops
->trampoline
,
3596 add_trampoline_func(m
, ops
, rec
);
3597 ops
= ftrace_find_tramp_ops_next(rec
, ops
);
3600 seq_puts(m
, "\ttramp: ERROR!");
3602 add_trampoline_func(m
, NULL
, rec
);
3604 if (rec
->flags
& FTRACE_FL_DIRECT
) {
3605 unsigned long direct
;
3607 direct
= find_rec_direct(rec
->ip
);
3609 seq_printf(m
, "\n\tdirect-->%pS", (void *)direct
);
3618 static const struct seq_operations show_ftrace_seq_ops
= {
3626 ftrace_avail_open(struct inode
*inode
, struct file
*file
)
3628 struct ftrace_iterator
*iter
;
3631 ret
= security_locked_down(LOCKDOWN_TRACEFS
);
3635 if (unlikely(ftrace_disabled
))
3638 iter
= __seq_open_private(file
, &show_ftrace_seq_ops
, sizeof(*iter
));
3642 iter
->pg
= ftrace_pages_start
;
3643 iter
->ops
= &global_ops
;
3649 ftrace_enabled_open(struct inode
*inode
, struct file
*file
)
3651 struct ftrace_iterator
*iter
;
3654 * This shows us what functions are currently being
3655 * traced and by what. Not sure if we want lockdown
3656 * to hide such critical information for an admin.
3657 * Although, perhaps it can show information we don't
3658 * want people to see, but if something is tracing
3659 * something, we probably want to know about it.
3662 iter
= __seq_open_private(file
, &show_ftrace_seq_ops
, sizeof(*iter
));
3666 iter
->pg
= ftrace_pages_start
;
3667 iter
->flags
= FTRACE_ITER_ENABLED
;
3668 iter
->ops
= &global_ops
;
3674 * ftrace_regex_open - initialize function tracer filter files
3675 * @ops: The ftrace_ops that hold the hash filters
3676 * @flag: The type of filter to process
3677 * @inode: The inode, usually passed in to your open routine
3678 * @file: The file, usually passed in to your open routine
3680 * ftrace_regex_open() initializes the filter files for the
3681 * @ops. Depending on @flag it may process the filter hash or
3682 * the notrace hash of @ops. With this called from the open
3683 * routine, you can use ftrace_filter_write() for the write
3684 * routine if @flag has FTRACE_ITER_FILTER set, or
3685 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3686 * tracing_lseek() should be used as the lseek routine, and
3687 * release must call ftrace_regex_release().
3690 ftrace_regex_open(struct ftrace_ops
*ops
, int flag
,
3691 struct inode
*inode
, struct file
*file
)
3693 struct ftrace_iterator
*iter
;
3694 struct ftrace_hash
*hash
;
3695 struct list_head
*mod_head
;
3696 struct trace_array
*tr
= ops
->private;
3699 ftrace_ops_init(ops
);
3701 if (unlikely(ftrace_disabled
))
3704 if (tracing_check_open_get_tr(tr
))
3707 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
3711 if (trace_parser_get_init(&iter
->parser
, FTRACE_BUFF_MAX
))
3718 mutex_lock(&ops
->func_hash
->regex_lock
);
3720 if (flag
& FTRACE_ITER_NOTRACE
) {
3721 hash
= ops
->func_hash
->notrace_hash
;
3722 mod_head
= tr
? &tr
->mod_notrace
: NULL
;
3724 hash
= ops
->func_hash
->filter_hash
;
3725 mod_head
= tr
? &tr
->mod_trace
: NULL
;
3728 iter
->mod_list
= mod_head
;
3730 if (file
->f_mode
& FMODE_WRITE
) {
3731 const int size_bits
= FTRACE_HASH_DEFAULT_BITS
;
3733 if (file
->f_flags
& O_TRUNC
) {
3734 iter
->hash
= alloc_ftrace_hash(size_bits
);
3735 clear_ftrace_mod_list(mod_head
);
3737 iter
->hash
= alloc_and_copy_ftrace_hash(size_bits
, hash
);
3741 trace_parser_put(&iter
->parser
);
3749 if (file
->f_mode
& FMODE_READ
) {
3750 iter
->pg
= ftrace_pages_start
;
3752 ret
= seq_open(file
, &show_ftrace_seq_ops
);
3754 struct seq_file
*m
= file
->private_data
;
3758 free_ftrace_hash(iter
->hash
);
3759 trace_parser_put(&iter
->parser
);
3762 file
->private_data
= iter
;
3765 mutex_unlock(&ops
->func_hash
->regex_lock
);
3771 trace_array_put(tr
);
3778 ftrace_filter_open(struct inode
*inode
, struct file
*file
)
3780 struct ftrace_ops
*ops
= inode
->i_private
;
3782 /* Checks for tracefs lockdown */
3783 return ftrace_regex_open(ops
,
3784 FTRACE_ITER_FILTER
| FTRACE_ITER_DO_PROBES
,
3789 ftrace_notrace_open(struct inode
*inode
, struct file
*file
)
3791 struct ftrace_ops
*ops
= inode
->i_private
;
3793 /* Checks for tracefs lockdown */
3794 return ftrace_regex_open(ops
, FTRACE_ITER_NOTRACE
,
3798 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3799 struct ftrace_glob
{
3806 * If symbols in an architecture don't correspond exactly to the user-visible
3807 * name of what they represent, it is possible to define this function to
3808 * perform the necessary adjustments.
3810 char * __weak
arch_ftrace_match_adjust(char *str
, const char *search
)
3815 static int ftrace_match(char *str
, struct ftrace_glob
*g
)
3820 str
= arch_ftrace_match_adjust(str
, g
->search
);
3824 if (strcmp(str
, g
->search
) == 0)
3827 case MATCH_FRONT_ONLY
:
3828 if (strncmp(str
, g
->search
, g
->len
) == 0)
3831 case MATCH_MIDDLE_ONLY
:
3832 if (strstr(str
, g
->search
))
3835 case MATCH_END_ONLY
:
3837 if (slen
>= g
->len
&&
3838 memcmp(str
+ slen
- g
->len
, g
->search
, g
->len
) == 0)
3842 if (glob_match(g
->search
, str
))
3851 enter_record(struct ftrace_hash
*hash
, struct dyn_ftrace
*rec
, int clear_filter
)
3853 struct ftrace_func_entry
*entry
;
3856 entry
= ftrace_lookup_ip(hash
, rec
->ip
);
3858 /* Do nothing if it doesn't exist */
3862 free_hash_entry(hash
, entry
);
3864 /* Do nothing if it exists */
3868 ret
= add_hash_entry(hash
, rec
->ip
);
3874 add_rec_by_index(struct ftrace_hash
*hash
, struct ftrace_glob
*func_g
,
3877 long index
= simple_strtoul(func_g
->search
, NULL
, 0);
3878 struct ftrace_page
*pg
;
3879 struct dyn_ftrace
*rec
;
3881 /* The index starts at 1 */
3885 do_for_each_ftrace_rec(pg
, rec
) {
3886 if (pg
->index
<= index
) {
3888 /* this is a double loop, break goes to the next page */
3891 rec
= &pg
->records
[index
];
3892 enter_record(hash
, rec
, clear_filter
);
3894 } while_for_each_ftrace_rec();
3899 ftrace_match_record(struct dyn_ftrace
*rec
, struct ftrace_glob
*func_g
,
3900 struct ftrace_glob
*mod_g
, int exclude_mod
)
3902 char str
[KSYM_SYMBOL_LEN
];
3905 kallsyms_lookup(rec
->ip
, NULL
, NULL
, &modname
, str
);
3908 int mod_matches
= (modname
) ? ftrace_match(modname
, mod_g
) : 0;
3910 /* blank module name to match all modules */
3912 /* blank module globbing: modname xor exclude_mod */
3913 if (!exclude_mod
!= !modname
)
3919 * exclude_mod is set to trace everything but the given
3920 * module. If it is set and the module matches, then
3921 * return 0. If it is not set, and the module doesn't match
3922 * also return 0. Otherwise, check the function to see if
3925 if (!mod_matches
== !exclude_mod
)
3928 /* blank search means to match all funcs in the mod */
3933 return ftrace_match(str
, func_g
);
3937 match_records(struct ftrace_hash
*hash
, char *func
, int len
, char *mod
)
3939 struct ftrace_page
*pg
;
3940 struct dyn_ftrace
*rec
;
3941 struct ftrace_glob func_g
= { .type
= MATCH_FULL
};
3942 struct ftrace_glob mod_g
= { .type
= MATCH_FULL
};
3943 struct ftrace_glob
*mod_match
= (mod
) ? &mod_g
: NULL
;
3944 int exclude_mod
= 0;
3947 int clear_filter
= 0;
3950 func_g
.type
= filter_parse_regex(func
, len
, &func_g
.search
,
3952 func_g
.len
= strlen(func_g
.search
);
3956 mod_g
.type
= filter_parse_regex(mod
, strlen(mod
),
3957 &mod_g
.search
, &exclude_mod
);
3958 mod_g
.len
= strlen(mod_g
.search
);
3961 mutex_lock(&ftrace_lock
);
3963 if (unlikely(ftrace_disabled
))
3966 if (func_g
.type
== MATCH_INDEX
) {
3967 found
= add_rec_by_index(hash
, &func_g
, clear_filter
);
3971 do_for_each_ftrace_rec(pg
, rec
) {
3973 if (rec
->flags
& FTRACE_FL_DISABLED
)
3976 if (ftrace_match_record(rec
, &func_g
, mod_match
, exclude_mod
)) {
3977 ret
= enter_record(hash
, rec
, clear_filter
);
3984 } while_for_each_ftrace_rec();
3986 mutex_unlock(&ftrace_lock
);
3992 ftrace_match_records(struct ftrace_hash
*hash
, char *buff
, int len
)
3994 return match_records(hash
, buff
, len
, NULL
);
3997 static void ftrace_ops_update_code(struct ftrace_ops
*ops
,
3998 struct ftrace_ops_hash
*old_hash
)
4000 struct ftrace_ops
*op
;
4002 if (!ftrace_enabled
)
4005 if (ops
->flags
& FTRACE_OPS_FL_ENABLED
) {
4006 ftrace_run_modify_code(ops
, FTRACE_UPDATE_CALLS
, old_hash
);
4011 * If this is the shared global_ops filter, then we need to
4012 * check if there is another ops that shares it, is enabled.
4013 * If so, we still need to run the modify code.
4015 if (ops
->func_hash
!= &global_ops
.local_hash
)
4018 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
4019 if (op
->func_hash
== &global_ops
.local_hash
&&
4020 op
->flags
& FTRACE_OPS_FL_ENABLED
) {
4021 ftrace_run_modify_code(op
, FTRACE_UPDATE_CALLS
, old_hash
);
4022 /* Only need to do this once */
4025 } while_for_each_ftrace_op(op
);
4028 static int ftrace_hash_move_and_update_ops(struct ftrace_ops
*ops
,
4029 struct ftrace_hash
**orig_hash
,
4030 struct ftrace_hash
*hash
,
4033 struct ftrace_ops_hash old_hash_ops
;
4034 struct ftrace_hash
*old_hash
;
4037 old_hash
= *orig_hash
;
4038 old_hash_ops
.filter_hash
= ops
->func_hash
->filter_hash
;
4039 old_hash_ops
.notrace_hash
= ops
->func_hash
->notrace_hash
;
4040 ret
= ftrace_hash_move(ops
, enable
, orig_hash
, hash
);
4042 ftrace_ops_update_code(ops
, &old_hash_ops
);
4043 free_ftrace_hash_rcu(old_hash
);
4048 static bool module_exists(const char *module
)
4050 /* All modules have the symbol __this_module */
4051 static const char this_mod
[] = "__this_module";
4052 char modname
[MAX_PARAM_PREFIX_LEN
+ sizeof(this_mod
) + 2];
4056 n
= snprintf(modname
, sizeof(modname
), "%s:%s", module
, this_mod
);
4058 if (n
> sizeof(modname
) - 1)
4061 val
= module_kallsyms_lookup_name(modname
);
4065 static int cache_mod(struct trace_array
*tr
,
4066 const char *func
, char *module
, int enable
)
4068 struct ftrace_mod_load
*ftrace_mod
, *n
;
4069 struct list_head
*head
= enable
? &tr
->mod_trace
: &tr
->mod_notrace
;
4072 mutex_lock(&ftrace_lock
);
4074 /* We do not cache inverse filters */
4075 if (func
[0] == '!') {
4079 /* Look to remove this hash */
4080 list_for_each_entry_safe(ftrace_mod
, n
, head
, list
) {
4081 if (strcmp(ftrace_mod
->module
, module
) != 0)
4084 /* no func matches all */
4085 if (strcmp(func
, "*") == 0 ||
4086 (ftrace_mod
->func
&&
4087 strcmp(ftrace_mod
->func
, func
) == 0)) {
4089 free_ftrace_mod(ftrace_mod
);
4097 /* We only care about modules that have not been loaded yet */
4098 if (module_exists(module
))
4101 /* Save this string off, and execute it when the module is loaded */
4102 ret
= ftrace_add_mod(tr
, func
, module
, enable
);
4104 mutex_unlock(&ftrace_lock
);
4110 ftrace_set_regex(struct ftrace_ops
*ops
, unsigned char *buf
, int len
,
4111 int reset
, int enable
);
4113 #ifdef CONFIG_MODULES
4114 static void process_mod_list(struct list_head
*head
, struct ftrace_ops
*ops
,
4115 char *mod
, bool enable
)
4117 struct ftrace_mod_load
*ftrace_mod
, *n
;
4118 struct ftrace_hash
**orig_hash
, *new_hash
;
4119 LIST_HEAD(process_mods
);
4123 mutex_lock(&ops
->func_hash
->regex_lock
);
4126 orig_hash
= &ops
->func_hash
->filter_hash
;
4128 orig_hash
= &ops
->func_hash
->notrace_hash
;
4130 new_hash
= alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
,
4133 goto out
; /* warn? */
4135 mutex_lock(&ftrace_lock
);
4137 list_for_each_entry_safe(ftrace_mod
, n
, head
, list
) {
4139 if (strcmp(ftrace_mod
->module
, mod
) != 0)
4142 if (ftrace_mod
->func
)
4143 func
= kstrdup(ftrace_mod
->func
, GFP_KERNEL
);
4145 func
= kstrdup("*", GFP_KERNEL
);
4147 if (!func
) /* warn? */
4150 list_del(&ftrace_mod
->list
);
4151 list_add(&ftrace_mod
->list
, &process_mods
);
4153 /* Use the newly allocated func, as it may be "*" */
4154 kfree(ftrace_mod
->func
);
4155 ftrace_mod
->func
= func
;
4158 mutex_unlock(&ftrace_lock
);
4160 list_for_each_entry_safe(ftrace_mod
, n
, &process_mods
, list
) {
4162 func
= ftrace_mod
->func
;
4164 /* Grabs ftrace_lock, which is why we have this extra step */
4165 match_records(new_hash
, func
, strlen(func
), mod
);
4166 free_ftrace_mod(ftrace_mod
);
4169 if (enable
&& list_empty(head
))
4170 new_hash
->flags
&= ~FTRACE_HASH_FL_MOD
;
4172 mutex_lock(&ftrace_lock
);
4174 ret
= ftrace_hash_move_and_update_ops(ops
, orig_hash
,
4176 mutex_unlock(&ftrace_lock
);
4179 mutex_unlock(&ops
->func_hash
->regex_lock
);
4181 free_ftrace_hash(new_hash
);
4184 static void process_cached_mods(const char *mod_name
)
4186 struct trace_array
*tr
;
4189 mod
= kstrdup(mod_name
, GFP_KERNEL
);
4193 mutex_lock(&trace_types_lock
);
4194 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
4195 if (!list_empty(&tr
->mod_trace
))
4196 process_mod_list(&tr
->mod_trace
, tr
->ops
, mod
, true);
4197 if (!list_empty(&tr
->mod_notrace
))
4198 process_mod_list(&tr
->mod_notrace
, tr
->ops
, mod
, false);
4200 mutex_unlock(&trace_types_lock
);
4207 * We register the module command as a template to show others how
4208 * to register the a command as well.
4212 ftrace_mod_callback(struct trace_array
*tr
, struct ftrace_hash
*hash
,
4213 char *func_orig
, char *cmd
, char *module
, int enable
)
4218 /* match_records() modifies func, and we need the original */
4219 func
= kstrdup(func_orig
, GFP_KERNEL
);
4224 * cmd == 'mod' because we only registered this func
4225 * for the 'mod' ftrace_func_command.
4226 * But if you register one func with multiple commands,
4227 * you can tell which command was used by the cmd
4230 ret
= match_records(hash
, func
, strlen(func
), module
);
4234 return cache_mod(tr
, func_orig
, module
, enable
);
4240 static struct ftrace_func_command ftrace_mod_cmd
= {
4242 .func
= ftrace_mod_callback
,
4245 static int __init
ftrace_mod_cmd_init(void)
4247 return register_ftrace_command(&ftrace_mod_cmd
);
4249 core_initcall(ftrace_mod_cmd_init
);
4251 static void function_trace_probe_call(unsigned long ip
, unsigned long parent_ip
,
4252 struct ftrace_ops
*op
, struct pt_regs
*pt_regs
)
4254 struct ftrace_probe_ops
*probe_ops
;
4255 struct ftrace_func_probe
*probe
;
4257 probe
= container_of(op
, struct ftrace_func_probe
, ops
);
4258 probe_ops
= probe
->probe_ops
;
4261 * Disable preemption for these calls to prevent a RCU grace
4262 * period. This syncs the hash iteration and freeing of items
4263 * on the hash. rcu_read_lock is too dangerous here.
4265 preempt_disable_notrace();
4266 probe_ops
->func(ip
, parent_ip
, probe
->tr
, probe_ops
, probe
->data
);
4267 preempt_enable_notrace();
4270 struct ftrace_func_map
{
4271 struct ftrace_func_entry entry
;
4275 struct ftrace_func_mapper
{
4276 struct ftrace_hash hash
;
4280 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4282 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4284 struct ftrace_func_mapper
*allocate_ftrace_func_mapper(void)
4286 struct ftrace_hash
*hash
;
4289 * The mapper is simply a ftrace_hash, but since the entries
4290 * in the hash are not ftrace_func_entry type, we define it
4291 * as a separate structure.
4293 hash
= alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
);
4294 return (struct ftrace_func_mapper
*)hash
;
4298 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4299 * @mapper: The mapper that has the ip maps
4300 * @ip: the instruction pointer to find the data for
4302 * Returns the data mapped to @ip if found otherwise NULL. The return
4303 * is actually the address of the mapper data pointer. The address is
4304 * returned for use cases where the data is no bigger than a long, and
4305 * the user can use the data pointer as its data instead of having to
4306 * allocate more memory for the reference.
4308 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper
*mapper
,
4311 struct ftrace_func_entry
*entry
;
4312 struct ftrace_func_map
*map
;
4314 entry
= ftrace_lookup_ip(&mapper
->hash
, ip
);
4318 map
= (struct ftrace_func_map
*)entry
;
4323 * ftrace_func_mapper_add_ip - Map some data to an ip
4324 * @mapper: The mapper that has the ip maps
4325 * @ip: The instruction pointer address to map @data to
4326 * @data: The data to map to @ip
4328 * Returns 0 on succes otherwise an error.
4330 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper
*mapper
,
4331 unsigned long ip
, void *data
)
4333 struct ftrace_func_entry
*entry
;
4334 struct ftrace_func_map
*map
;
4336 entry
= ftrace_lookup_ip(&mapper
->hash
, ip
);
4340 map
= kmalloc(sizeof(*map
), GFP_KERNEL
);
4347 __add_hash_entry(&mapper
->hash
, &map
->entry
);
4353 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4354 * @mapper: The mapper that has the ip maps
4355 * @ip: The instruction pointer address to remove the data from
4357 * Returns the data if it is found, otherwise NULL.
4358 * Note, if the data pointer is used as the data itself, (see
4359 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4360 * if the data pointer was set to zero.
4362 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper
*mapper
,
4365 struct ftrace_func_entry
*entry
;
4366 struct ftrace_func_map
*map
;
4369 entry
= ftrace_lookup_ip(&mapper
->hash
, ip
);
4373 map
= (struct ftrace_func_map
*)entry
;
4376 remove_hash_entry(&mapper
->hash
, entry
);
4383 * free_ftrace_func_mapper - free a mapping of ips and data
4384 * @mapper: The mapper that has the ip maps
4385 * @free_func: A function to be called on each data item.
4387 * This is used to free the function mapper. The @free_func is optional
4388 * and can be used if the data needs to be freed as well.
4390 void free_ftrace_func_mapper(struct ftrace_func_mapper
*mapper
,
4391 ftrace_mapper_func free_func
)
4393 struct ftrace_func_entry
*entry
;
4394 struct ftrace_func_map
*map
;
4395 struct hlist_head
*hhd
;
4401 if (free_func
&& mapper
->hash
.count
) {
4402 size
= 1 << mapper
->hash
.size_bits
;
4403 for (i
= 0; i
< size
; i
++) {
4404 hhd
= &mapper
->hash
.buckets
[i
];
4405 hlist_for_each_entry(entry
, hhd
, hlist
) {
4406 map
= (struct ftrace_func_map
*)entry
;
4411 free_ftrace_hash(&mapper
->hash
);
4414 static void release_probe(struct ftrace_func_probe
*probe
)
4416 struct ftrace_probe_ops
*probe_ops
;
4418 mutex_lock(&ftrace_lock
);
4420 WARN_ON(probe
->ref
<= 0);
4422 /* Subtract the ref that was used to protect this instance */
4426 probe_ops
= probe
->probe_ops
;
4428 * Sending zero as ip tells probe_ops to free
4429 * the probe->data itself
4431 if (probe_ops
->free
)
4432 probe_ops
->free(probe_ops
, probe
->tr
, 0, probe
->data
);
4433 list_del(&probe
->list
);
4436 mutex_unlock(&ftrace_lock
);
4439 static void acquire_probe_locked(struct ftrace_func_probe
*probe
)
4442 * Add one ref to keep it from being freed when releasing the
4443 * ftrace_lock mutex.
4449 register_ftrace_function_probe(char *glob
, struct trace_array
*tr
,
4450 struct ftrace_probe_ops
*probe_ops
,
4453 struct ftrace_func_entry
*entry
;
4454 struct ftrace_func_probe
*probe
;
4455 struct ftrace_hash
**orig_hash
;
4456 struct ftrace_hash
*old_hash
;
4457 struct ftrace_hash
*hash
;
4466 /* We do not support '!' for function probes */
4467 if (WARN_ON(glob
[0] == '!'))
4471 mutex_lock(&ftrace_lock
);
4472 /* Check if the probe_ops is already registered */
4473 list_for_each_entry(probe
, &tr
->func_probes
, list
) {
4474 if (probe
->probe_ops
== probe_ops
)
4477 if (&probe
->list
== &tr
->func_probes
) {
4478 probe
= kzalloc(sizeof(*probe
), GFP_KERNEL
);
4480 mutex_unlock(&ftrace_lock
);
4483 probe
->probe_ops
= probe_ops
;
4484 probe
->ops
.func
= function_trace_probe_call
;
4486 ftrace_ops_init(&probe
->ops
);
4487 list_add(&probe
->list
, &tr
->func_probes
);
4490 acquire_probe_locked(probe
);
4492 mutex_unlock(&ftrace_lock
);
4495 * Note, there's a small window here that the func_hash->filter_hash
4496 * may be NULL or empty. Need to be carefule when reading the loop.
4498 mutex_lock(&probe
->ops
.func_hash
->regex_lock
);
4500 orig_hash
= &probe
->ops
.func_hash
->filter_hash
;
4501 old_hash
= *orig_hash
;
4502 hash
= alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
, old_hash
);
4509 ret
= ftrace_match_records(hash
, glob
, strlen(glob
));
4511 /* Nothing found? */
4518 size
= 1 << hash
->size_bits
;
4519 for (i
= 0; i
< size
; i
++) {
4520 hlist_for_each_entry(entry
, &hash
->buckets
[i
], hlist
) {
4521 if (ftrace_lookup_ip(old_hash
, entry
->ip
))
4524 * The caller might want to do something special
4525 * for each function we find. We call the callback
4526 * to give the caller an opportunity to do so.
4528 if (probe_ops
->init
) {
4529 ret
= probe_ops
->init(probe_ops
, tr
,
4533 if (probe_ops
->free
&& count
)
4534 probe_ops
->free(probe_ops
, tr
,
4544 mutex_lock(&ftrace_lock
);
4547 /* Nothing was added? */
4552 ret
= ftrace_hash_move_and_update_ops(&probe
->ops
, orig_hash
,
4557 /* One ref for each new function traced */
4558 probe
->ref
+= count
;
4560 if (!(probe
->ops
.flags
& FTRACE_OPS_FL_ENABLED
))
4561 ret
= ftrace_startup(&probe
->ops
, 0);
4564 mutex_unlock(&ftrace_lock
);
4569 mutex_unlock(&probe
->ops
.func_hash
->regex_lock
);
4570 free_ftrace_hash(hash
);
4572 release_probe(probe
);
4577 if (!probe_ops
->free
|| !count
)
4580 /* Failed to do the move, need to call the free functions */
4581 for (i
= 0; i
< size
; i
++) {
4582 hlist_for_each_entry(entry
, &hash
->buckets
[i
], hlist
) {
4583 if (ftrace_lookup_ip(old_hash
, entry
->ip
))
4585 probe_ops
->free(probe_ops
, tr
, entry
->ip
, probe
->data
);
4592 unregister_ftrace_function_probe_func(char *glob
, struct trace_array
*tr
,
4593 struct ftrace_probe_ops
*probe_ops
)
4595 struct ftrace_ops_hash old_hash_ops
;
4596 struct ftrace_func_entry
*entry
;
4597 struct ftrace_func_probe
*probe
;
4598 struct ftrace_glob func_g
;
4599 struct ftrace_hash
**orig_hash
;
4600 struct ftrace_hash
*old_hash
;
4601 struct ftrace_hash
*hash
= NULL
;
4602 struct hlist_node
*tmp
;
4603 struct hlist_head hhd
;
4604 char str
[KSYM_SYMBOL_LEN
];
4606 int i
, ret
= -ENODEV
;
4609 if (!glob
|| !strlen(glob
) || !strcmp(glob
, "*"))
4610 func_g
.search
= NULL
;
4614 func_g
.type
= filter_parse_regex(glob
, strlen(glob
),
4615 &func_g
.search
, ¬);
4616 func_g
.len
= strlen(func_g
.search
);
4618 /* we do not support '!' for function probes */
4623 mutex_lock(&ftrace_lock
);
4624 /* Check if the probe_ops is already registered */
4625 list_for_each_entry(probe
, &tr
->func_probes
, list
) {
4626 if (probe
->probe_ops
== probe_ops
)
4629 if (&probe
->list
== &tr
->func_probes
)
4630 goto err_unlock_ftrace
;
4633 if (!(probe
->ops
.flags
& FTRACE_OPS_FL_INITIALIZED
))
4634 goto err_unlock_ftrace
;
4636 acquire_probe_locked(probe
);
4638 mutex_unlock(&ftrace_lock
);
4640 mutex_lock(&probe
->ops
.func_hash
->regex_lock
);
4642 orig_hash
= &probe
->ops
.func_hash
->filter_hash
;
4643 old_hash
= *orig_hash
;
4645 if (ftrace_hash_empty(old_hash
))
4648 old_hash_ops
.filter_hash
= old_hash
;
4649 /* Probes only have filters */
4650 old_hash_ops
.notrace_hash
= NULL
;
4653 hash
= alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
, old_hash
);
4657 INIT_HLIST_HEAD(&hhd
);
4659 size
= 1 << hash
->size_bits
;
4660 for (i
= 0; i
< size
; i
++) {
4661 hlist_for_each_entry_safe(entry
, tmp
, &hash
->buckets
[i
], hlist
) {
4663 if (func_g
.search
) {
4664 kallsyms_lookup(entry
->ip
, NULL
, NULL
,
4666 if (!ftrace_match(str
, &func_g
))
4670 remove_hash_entry(hash
, entry
);
4671 hlist_add_head(&entry
->hlist
, &hhd
);
4675 /* Nothing found? */
4681 mutex_lock(&ftrace_lock
);
4683 WARN_ON(probe
->ref
< count
);
4685 probe
->ref
-= count
;
4687 if (ftrace_hash_empty(hash
))
4688 ftrace_shutdown(&probe
->ops
, 0);
4690 ret
= ftrace_hash_move_and_update_ops(&probe
->ops
, orig_hash
,
4693 /* still need to update the function call sites */
4694 if (ftrace_enabled
&& !ftrace_hash_empty(hash
))
4695 ftrace_run_modify_code(&probe
->ops
, FTRACE_UPDATE_CALLS
,
4699 hlist_for_each_entry_safe(entry
, tmp
, &hhd
, hlist
) {
4700 hlist_del(&entry
->hlist
);
4701 if (probe_ops
->free
)
4702 probe_ops
->free(probe_ops
, tr
, entry
->ip
, probe
->data
);
4705 mutex_unlock(&ftrace_lock
);
4708 mutex_unlock(&probe
->ops
.func_hash
->regex_lock
);
4709 free_ftrace_hash(hash
);
4711 release_probe(probe
);
4716 mutex_unlock(&ftrace_lock
);
4720 void clear_ftrace_function_probes(struct trace_array
*tr
)
4722 struct ftrace_func_probe
*probe
, *n
;
4724 list_for_each_entry_safe(probe
, n
, &tr
->func_probes
, list
)
4725 unregister_ftrace_function_probe_func(NULL
, tr
, probe
->probe_ops
);
4728 static LIST_HEAD(ftrace_commands
);
4729 static DEFINE_MUTEX(ftrace_cmd_mutex
);
4732 * Currently we only register ftrace commands from __init, so mark this
4735 __init
int register_ftrace_command(struct ftrace_func_command
*cmd
)
4737 struct ftrace_func_command
*p
;
4740 mutex_lock(&ftrace_cmd_mutex
);
4741 list_for_each_entry(p
, &ftrace_commands
, list
) {
4742 if (strcmp(cmd
->name
, p
->name
) == 0) {
4747 list_add(&cmd
->list
, &ftrace_commands
);
4749 mutex_unlock(&ftrace_cmd_mutex
);
4755 * Currently we only unregister ftrace commands from __init, so mark
4758 __init
int unregister_ftrace_command(struct ftrace_func_command
*cmd
)
4760 struct ftrace_func_command
*p
, *n
;
4763 mutex_lock(&ftrace_cmd_mutex
);
4764 list_for_each_entry_safe(p
, n
, &ftrace_commands
, list
) {
4765 if (strcmp(cmd
->name
, p
->name
) == 0) {
4767 list_del_init(&p
->list
);
4772 mutex_unlock(&ftrace_cmd_mutex
);
4777 static int ftrace_process_regex(struct ftrace_iterator
*iter
,
4778 char *buff
, int len
, int enable
)
4780 struct ftrace_hash
*hash
= iter
->hash
;
4781 struct trace_array
*tr
= iter
->ops
->private;
4782 char *func
, *command
, *next
= buff
;
4783 struct ftrace_func_command
*p
;
4786 func
= strsep(&next
, ":");
4789 ret
= ftrace_match_records(hash
, func
, len
);
4799 command
= strsep(&next
, ":");
4801 mutex_lock(&ftrace_cmd_mutex
);
4802 list_for_each_entry(p
, &ftrace_commands
, list
) {
4803 if (strcmp(p
->name
, command
) == 0) {
4804 ret
= p
->func(tr
, hash
, func
, command
, next
, enable
);
4809 mutex_unlock(&ftrace_cmd_mutex
);
4815 ftrace_regex_write(struct file
*file
, const char __user
*ubuf
,
4816 size_t cnt
, loff_t
*ppos
, int enable
)
4818 struct ftrace_iterator
*iter
;
4819 struct trace_parser
*parser
;
4825 if (file
->f_mode
& FMODE_READ
) {
4826 struct seq_file
*m
= file
->private_data
;
4829 iter
= file
->private_data
;
4831 if (unlikely(ftrace_disabled
))
4834 /* iter->hash is a local copy, so we don't need regex_lock */
4836 parser
= &iter
->parser
;
4837 read
= trace_get_user(parser
, ubuf
, cnt
, ppos
);
4839 if (read
>= 0 && trace_parser_loaded(parser
) &&
4840 !trace_parser_cont(parser
)) {
4841 ret
= ftrace_process_regex(iter
, parser
->buffer
,
4842 parser
->idx
, enable
);
4843 trace_parser_clear(parser
);
4854 ftrace_filter_write(struct file
*file
, const char __user
*ubuf
,
4855 size_t cnt
, loff_t
*ppos
)
4857 return ftrace_regex_write(file
, ubuf
, cnt
, ppos
, 1);
4861 ftrace_notrace_write(struct file
*file
, const char __user
*ubuf
,
4862 size_t cnt
, loff_t
*ppos
)
4864 return ftrace_regex_write(file
, ubuf
, cnt
, ppos
, 0);
4868 ftrace_match_addr(struct ftrace_hash
*hash
, unsigned long ip
, int remove
)
4870 struct ftrace_func_entry
*entry
;
4872 if (!ftrace_location(ip
))
4876 entry
= ftrace_lookup_ip(hash
, ip
);
4879 free_hash_entry(hash
, entry
);
4883 return add_hash_entry(hash
, ip
);
4887 ftrace_set_hash(struct ftrace_ops
*ops
, unsigned char *buf
, int len
,
4888 unsigned long ip
, int remove
, int reset
, int enable
)
4890 struct ftrace_hash
**orig_hash
;
4891 struct ftrace_hash
*hash
;
4894 if (unlikely(ftrace_disabled
))
4897 mutex_lock(&ops
->func_hash
->regex_lock
);
4900 orig_hash
= &ops
->func_hash
->filter_hash
;
4902 orig_hash
= &ops
->func_hash
->notrace_hash
;
4905 hash
= alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
);
4907 hash
= alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
, *orig_hash
);
4911 goto out_regex_unlock
;
4914 if (buf
&& !ftrace_match_records(hash
, buf
, len
)) {
4916 goto out_regex_unlock
;
4919 ret
= ftrace_match_addr(hash
, ip
, remove
);
4921 goto out_regex_unlock
;
4924 mutex_lock(&ftrace_lock
);
4925 ret
= ftrace_hash_move_and_update_ops(ops
, orig_hash
, hash
, enable
);
4926 mutex_unlock(&ftrace_lock
);
4929 mutex_unlock(&ops
->func_hash
->regex_lock
);
4931 free_ftrace_hash(hash
);
4936 ftrace_set_addr(struct ftrace_ops
*ops
, unsigned long ip
, int remove
,
4937 int reset
, int enable
)
4939 return ftrace_set_hash(ops
, NULL
, 0, ip
, remove
, reset
, enable
);
4942 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
4944 struct ftrace_direct_func
{
4945 struct list_head next
;
4950 static LIST_HEAD(ftrace_direct_funcs
);
4953 * ftrace_find_direct_func - test an address if it is a registered direct caller
4954 * @addr: The address of a registered direct caller
4956 * This searches to see if a ftrace direct caller has been registered
4957 * at a specific address, and if so, it returns a descriptor for it.
4959 * This can be used by architecture code to see if an address is
4960 * a direct caller (trampoline) attached to a fentry/mcount location.
4961 * This is useful for the function_graph tracer, as it may need to
4962 * do adjustments if it traced a location that also has a direct
4963 * trampoline attached to it.
4965 struct ftrace_direct_func
*ftrace_find_direct_func(unsigned long addr
)
4967 struct ftrace_direct_func
*entry
;
4970 /* May be called by fgraph trampoline (protected by rcu tasks) */
4971 list_for_each_entry_rcu(entry
, &ftrace_direct_funcs
, next
) {
4972 if (entry
->addr
== addr
) {
4984 * register_ftrace_direct - Call a custom trampoline directly
4985 * @ip: The address of the nop at the beginning of a function
4986 * @addr: The address of the trampoline to call at @ip
4988 * This is used to connect a direct call from the nop location (@ip)
4989 * at the start of ftrace traced functions. The location that it calls
4990 * (@addr) must be able to handle a direct call, and save the parameters
4991 * of the function being traced, and restore them (or inject new ones
4992 * if needed), before returning.
4996 * -EBUSY - Another direct function is already attached (there can be only one)
4997 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
4998 * -ENOMEM - There was an allocation failure.
5000 int register_ftrace_direct(unsigned long ip
, unsigned long addr
)
5002 struct ftrace_direct_func
*direct
;
5003 struct ftrace_func_entry
*entry
;
5004 struct ftrace_hash
*free_hash
= NULL
;
5005 struct dyn_ftrace
*rec
;
5008 mutex_lock(&direct_mutex
);
5010 /* See if there's a direct function at @ip already */
5011 if (find_rec_direct(ip
))
5015 rec
= lookup_rec(ip
, ip
);
5020 * Check if the rec says it has a direct call but we didn't
5023 if (WARN_ON(rec
->flags
& FTRACE_FL_DIRECT
))
5026 /* Make sure the ip points to the exact record */
5027 if (ip
!= rec
->ip
) {
5029 /* Need to check this ip for a direct. */
5030 if (find_rec_direct(ip
))
5035 if (ftrace_hash_empty(direct_functions
) ||
5036 direct_functions
->count
> 2 * (1 << direct_functions
->size_bits
)) {
5037 struct ftrace_hash
*new_hash
;
5038 int size
= ftrace_hash_empty(direct_functions
) ? 0 :
5039 direct_functions
->count
+ 1;
5044 new_hash
= dup_hash(direct_functions
, size
);
5048 free_hash
= direct_functions
;
5049 direct_functions
= new_hash
;
5052 entry
= kmalloc(sizeof(*entry
), GFP_KERNEL
);
5056 direct
= ftrace_find_direct_func(addr
);
5058 direct
= kmalloc(sizeof(*direct
), GFP_KERNEL
);
5063 direct
->addr
= addr
;
5065 list_add_rcu(&direct
->next
, &ftrace_direct_funcs
);
5066 ftrace_direct_func_count
++;
5070 entry
->direct
= addr
;
5071 __add_hash_entry(direct_functions
, entry
);
5073 ret
= ftrace_set_filter_ip(&direct_ops
, ip
, 0, 0);
5075 remove_hash_entry(direct_functions
, entry
);
5077 if (!ret
&& !(direct_ops
.flags
& FTRACE_OPS_FL_ENABLED
)) {
5078 ret
= register_ftrace_function(&direct_ops
);
5080 ftrace_set_filter_ip(&direct_ops
, ip
, 1, 0);
5085 if (!direct
->count
) {
5086 list_del_rcu(&direct
->next
);
5087 synchronize_rcu_tasks();
5090 free_ftrace_hash(free_hash
);
5092 ftrace_direct_func_count
--;
5098 mutex_unlock(&direct_mutex
);
5101 synchronize_rcu_tasks();
5102 free_ftrace_hash(free_hash
);
5107 EXPORT_SYMBOL_GPL(register_ftrace_direct
);
5109 static struct ftrace_func_entry
*find_direct_entry(unsigned long *ip
,
5110 struct dyn_ftrace
**recp
)
5112 struct ftrace_func_entry
*entry
;
5113 struct dyn_ftrace
*rec
;
5115 rec
= lookup_rec(*ip
, *ip
);
5119 entry
= __ftrace_lookup_ip(direct_functions
, rec
->ip
);
5121 WARN_ON(rec
->flags
& FTRACE_FL_DIRECT
);
5125 WARN_ON(!(rec
->flags
& FTRACE_FL_DIRECT
));
5127 /* Passed in ip just needs to be on the call site */
5136 int unregister_ftrace_direct(unsigned long ip
, unsigned long addr
)
5138 struct ftrace_direct_func
*direct
;
5139 struct ftrace_func_entry
*entry
;
5142 mutex_lock(&direct_mutex
);
5144 entry
= find_direct_entry(&ip
, NULL
);
5148 if (direct_functions
->count
== 1)
5149 unregister_ftrace_function(&direct_ops
);
5151 ret
= ftrace_set_filter_ip(&direct_ops
, ip
, 1, 0);
5155 remove_hash_entry(direct_functions
, entry
);
5157 direct
= ftrace_find_direct_func(addr
);
5158 if (!WARN_ON(!direct
)) {
5159 /* This is the good path (see the ! before WARN) */
5161 WARN_ON(direct
->count
< 0);
5162 if (!direct
->count
) {
5163 list_del_rcu(&direct
->next
);
5164 synchronize_rcu_tasks();
5166 ftrace_direct_func_count
--;
5170 mutex_unlock(&direct_mutex
);
5174 EXPORT_SYMBOL_GPL(unregister_ftrace_direct
);
5176 static struct ftrace_ops stub_ops
= {
5177 .func
= ftrace_stub
,
5181 * ftrace_modify_direct_caller - modify ftrace nop directly
5182 * @entry: The ftrace hash entry of the direct helper for @rec
5183 * @rec: The record representing the function site to patch
5184 * @old_addr: The location that the site at @rec->ip currently calls
5185 * @new_addr: The location that the site at @rec->ip should call
5187 * An architecture may overwrite this function to optimize the
5188 * changing of the direct callback on an ftrace nop location.
5189 * This is called with the ftrace_lock mutex held, and no other
5190 * ftrace callbacks are on the associated record (@rec). Thus,
5191 * it is safe to modify the ftrace record, where it should be
5192 * currently calling @old_addr directly, to call @new_addr.
5194 * Safety checks should be made to make sure that the code at
5195 * @rec->ip is currently calling @old_addr. And this must
5196 * also update entry->direct to @new_addr.
5198 int __weak
ftrace_modify_direct_caller(struct ftrace_func_entry
*entry
,
5199 struct dyn_ftrace
*rec
,
5200 unsigned long old_addr
,
5201 unsigned long new_addr
)
5203 unsigned long ip
= rec
->ip
;
5207 * The ftrace_lock was used to determine if the record
5208 * had more than one registered user to it. If it did,
5209 * we needed to prevent that from changing to do the quick
5210 * switch. But if it did not (only a direct caller was attached)
5211 * then this function is called. But this function can deal
5212 * with attached callers to the rec that we care about, and
5213 * since this function uses standard ftrace calls that take
5214 * the ftrace_lock mutex, we need to release it.
5216 mutex_unlock(&ftrace_lock
);
5219 * By setting a stub function at the same address, we force
5220 * the code to call the iterator and the direct_ops helper.
5221 * This means that @ip does not call the direct call, and
5222 * we can simply modify it.
5224 ret
= ftrace_set_filter_ip(&stub_ops
, ip
, 0, 0);
5228 ret
= register_ftrace_function(&stub_ops
);
5230 ftrace_set_filter_ip(&stub_ops
, ip
, 1, 0);
5234 entry
->direct
= new_addr
;
5237 * By removing the stub, we put back the direct call, calling
5240 unregister_ftrace_function(&stub_ops
);
5241 ftrace_set_filter_ip(&stub_ops
, ip
, 1, 0);
5244 mutex_lock(&ftrace_lock
);
5250 * modify_ftrace_direct - Modify an existing direct call to call something else
5251 * @ip: The instruction pointer to modify
5252 * @old_addr: The address that the current @ip calls directly
5253 * @new_addr: The address that the @ip should call
5255 * This modifies a ftrace direct caller at an instruction pointer without
5256 * having to disable it first. The direct call will switch over to the
5257 * @new_addr without missing anything.
5259 * Returns: zero on success. Non zero on error, which includes:
5260 * -ENODEV : the @ip given has no direct caller attached
5261 * -EINVAL : the @old_addr does not match the current direct caller
5263 int modify_ftrace_direct(unsigned long ip
,
5264 unsigned long old_addr
, unsigned long new_addr
)
5266 struct ftrace_func_entry
*entry
;
5267 struct dyn_ftrace
*rec
;
5270 mutex_lock(&direct_mutex
);
5272 mutex_lock(&ftrace_lock
);
5273 entry
= find_direct_entry(&ip
, &rec
);
5278 if (entry
->direct
!= old_addr
)
5282 * If there's no other ftrace callback on the rec->ip location,
5283 * then it can be changed directly by the architecture.
5284 * If there is another caller, then we just need to change the
5285 * direct caller helper to point to @new_addr.
5287 if (ftrace_rec_count(rec
) == 1) {
5288 ret
= ftrace_modify_direct_caller(entry
, rec
, old_addr
, new_addr
);
5290 entry
->direct
= new_addr
;
5295 mutex_unlock(&ftrace_lock
);
5296 mutex_unlock(&direct_mutex
);
5299 EXPORT_SYMBOL_GPL(modify_ftrace_direct
);
5300 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
5303 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
5304 * @ops - the ops to set the filter with
5305 * @ip - the address to add to or remove from the filter.
5306 * @remove - non zero to remove the ip from the filter
5307 * @reset - non zero to reset all filters before applying this filter.
5309 * Filters denote which functions should be enabled when tracing is enabled
5310 * If @ip is NULL, it failes to update filter.
5312 int ftrace_set_filter_ip(struct ftrace_ops
*ops
, unsigned long ip
,
5313 int remove
, int reset
)
5315 ftrace_ops_init(ops
);
5316 return ftrace_set_addr(ops
, ip
, remove
, reset
, 1);
5318 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip
);
5321 * ftrace_ops_set_global_filter - setup ops to use global filters
5322 * @ops - the ops which will use the global filters
5324 * ftrace users who need global function trace filtering should call this.
5325 * It can set the global filter only if ops were not initialized before.
5327 void ftrace_ops_set_global_filter(struct ftrace_ops
*ops
)
5329 if (ops
->flags
& FTRACE_OPS_FL_INITIALIZED
)
5332 ftrace_ops_init(ops
);
5333 ops
->func_hash
= &global_ops
.local_hash
;
5335 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter
);
5338 ftrace_set_regex(struct ftrace_ops
*ops
, unsigned char *buf
, int len
,
5339 int reset
, int enable
)
5341 return ftrace_set_hash(ops
, buf
, len
, 0, 0, reset
, enable
);
5345 * ftrace_set_filter - set a function to filter on in ftrace
5346 * @ops - the ops to set the filter with
5347 * @buf - the string that holds the function filter text.
5348 * @len - the length of the string.
5349 * @reset - non zero to reset all filters before applying this filter.
5351 * Filters denote which functions should be enabled when tracing is enabled.
5352 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5354 int ftrace_set_filter(struct ftrace_ops
*ops
, unsigned char *buf
,
5357 ftrace_ops_init(ops
);
5358 return ftrace_set_regex(ops
, buf
, len
, reset
, 1);
5360 EXPORT_SYMBOL_GPL(ftrace_set_filter
);
5363 * ftrace_set_notrace - set a function to not trace in ftrace
5364 * @ops - the ops to set the notrace filter with
5365 * @buf - the string that holds the function notrace text.
5366 * @len - the length of the string.
5367 * @reset - non zero to reset all filters before applying this filter.
5369 * Notrace Filters denote which functions should not be enabled when tracing
5370 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5373 int ftrace_set_notrace(struct ftrace_ops
*ops
, unsigned char *buf
,
5376 ftrace_ops_init(ops
);
5377 return ftrace_set_regex(ops
, buf
, len
, reset
, 0);
5379 EXPORT_SYMBOL_GPL(ftrace_set_notrace
);
5381 * ftrace_set_global_filter - set a function to filter on with global tracers
5382 * @buf - the string that holds the function filter text.
5383 * @len - the length of the string.
5384 * @reset - non zero to reset all filters before applying this filter.
5386 * Filters denote which functions should be enabled when tracing is enabled.
5387 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5389 void ftrace_set_global_filter(unsigned char *buf
, int len
, int reset
)
5391 ftrace_set_regex(&global_ops
, buf
, len
, reset
, 1);
5393 EXPORT_SYMBOL_GPL(ftrace_set_global_filter
);
5396 * ftrace_set_global_notrace - set a function to not trace with global tracers
5397 * @buf - the string that holds the function notrace text.
5398 * @len - the length of the string.
5399 * @reset - non zero to reset all filters before applying this filter.
5401 * Notrace Filters denote which functions should not be enabled when tracing
5402 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5405 void ftrace_set_global_notrace(unsigned char *buf
, int len
, int reset
)
5407 ftrace_set_regex(&global_ops
, buf
, len
, reset
, 0);
5409 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace
);
5412 * command line interface to allow users to set filters on boot up.
5414 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
5415 static char ftrace_notrace_buf
[FTRACE_FILTER_SIZE
] __initdata
;
5416 static char ftrace_filter_buf
[FTRACE_FILTER_SIZE
] __initdata
;
5418 /* Used by function selftest to not test if filter is set */
5419 bool ftrace_filter_param __initdata
;
5421 static int __init
set_ftrace_notrace(char *str
)
5423 ftrace_filter_param
= true;
5424 strlcpy(ftrace_notrace_buf
, str
, FTRACE_FILTER_SIZE
);
5427 __setup("ftrace_notrace=", set_ftrace_notrace
);
5429 static int __init
set_ftrace_filter(char *str
)
5431 ftrace_filter_param
= true;
5432 strlcpy(ftrace_filter_buf
, str
, FTRACE_FILTER_SIZE
);
5435 __setup("ftrace_filter=", set_ftrace_filter
);
5437 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5438 static char ftrace_graph_buf
[FTRACE_FILTER_SIZE
] __initdata
;
5439 static char ftrace_graph_notrace_buf
[FTRACE_FILTER_SIZE
] __initdata
;
5440 static int ftrace_graph_set_hash(struct ftrace_hash
*hash
, char *buffer
);
5442 static int __init
set_graph_function(char *str
)
5444 strlcpy(ftrace_graph_buf
, str
, FTRACE_FILTER_SIZE
);
5447 __setup("ftrace_graph_filter=", set_graph_function
);
5449 static int __init
set_graph_notrace_function(char *str
)
5451 strlcpy(ftrace_graph_notrace_buf
, str
, FTRACE_FILTER_SIZE
);
5454 __setup("ftrace_graph_notrace=", set_graph_notrace_function
);
5456 static int __init
set_graph_max_depth_function(char *str
)
5460 fgraph_max_depth
= simple_strtoul(str
, NULL
, 0);
5463 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function
);
5465 static void __init
set_ftrace_early_graph(char *buf
, int enable
)
5469 struct ftrace_hash
*hash
;
5471 hash
= alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
);
5476 func
= strsep(&buf
, ",");
5477 /* we allow only one expression at a time */
5478 ret
= ftrace_graph_set_hash(hash
, func
);
5480 printk(KERN_DEBUG
"ftrace: function %s not "
5481 "traceable\n", func
);
5485 ftrace_graph_hash
= hash
;
5487 ftrace_graph_notrace_hash
= hash
;
5489 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5492 ftrace_set_early_filter(struct ftrace_ops
*ops
, char *buf
, int enable
)
5496 ftrace_ops_init(ops
);
5499 func
= strsep(&buf
, ",");
5500 ftrace_set_regex(ops
, func
, strlen(func
), 0, enable
);
5504 static void __init
set_ftrace_early_filters(void)
5506 if (ftrace_filter_buf
[0])
5507 ftrace_set_early_filter(&global_ops
, ftrace_filter_buf
, 1);
5508 if (ftrace_notrace_buf
[0])
5509 ftrace_set_early_filter(&global_ops
, ftrace_notrace_buf
, 0);
5510 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5511 if (ftrace_graph_buf
[0])
5512 set_ftrace_early_graph(ftrace_graph_buf
, 1);
5513 if (ftrace_graph_notrace_buf
[0])
5514 set_ftrace_early_graph(ftrace_graph_notrace_buf
, 0);
5515 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5518 int ftrace_regex_release(struct inode
*inode
, struct file
*file
)
5520 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
5521 struct ftrace_iterator
*iter
;
5522 struct ftrace_hash
**orig_hash
;
5523 struct trace_parser
*parser
;
5527 if (file
->f_mode
& FMODE_READ
) {
5529 seq_release(inode
, file
);
5531 iter
= file
->private_data
;
5533 parser
= &iter
->parser
;
5534 if (trace_parser_loaded(parser
)) {
5535 ftrace_match_records(iter
->hash
, parser
->buffer
, parser
->idx
);
5538 trace_parser_put(parser
);
5540 mutex_lock(&iter
->ops
->func_hash
->regex_lock
);
5542 if (file
->f_mode
& FMODE_WRITE
) {
5543 filter_hash
= !!(iter
->flags
& FTRACE_ITER_FILTER
);
5546 orig_hash
= &iter
->ops
->func_hash
->filter_hash
;
5547 if (iter
->tr
&& !list_empty(&iter
->tr
->mod_trace
))
5548 iter
->hash
->flags
|= FTRACE_HASH_FL_MOD
;
5550 orig_hash
= &iter
->ops
->func_hash
->notrace_hash
;
5552 mutex_lock(&ftrace_lock
);
5553 ret
= ftrace_hash_move_and_update_ops(iter
->ops
, orig_hash
,
5554 iter
->hash
, filter_hash
);
5555 mutex_unlock(&ftrace_lock
);
5557 /* For read only, the hash is the ops hash */
5561 mutex_unlock(&iter
->ops
->func_hash
->regex_lock
);
5562 free_ftrace_hash(iter
->hash
);
5564 trace_array_put(iter
->tr
);
5570 static const struct file_operations ftrace_avail_fops
= {
5571 .open
= ftrace_avail_open
,
5573 .llseek
= seq_lseek
,
5574 .release
= seq_release_private
,
5577 static const struct file_operations ftrace_enabled_fops
= {
5578 .open
= ftrace_enabled_open
,
5580 .llseek
= seq_lseek
,
5581 .release
= seq_release_private
,
5584 static const struct file_operations ftrace_filter_fops
= {
5585 .open
= ftrace_filter_open
,
5587 .write
= ftrace_filter_write
,
5588 .llseek
= tracing_lseek
,
5589 .release
= ftrace_regex_release
,
5592 static const struct file_operations ftrace_notrace_fops
= {
5593 .open
= ftrace_notrace_open
,
5595 .write
= ftrace_notrace_write
,
5596 .llseek
= tracing_lseek
,
5597 .release
= ftrace_regex_release
,
5600 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5602 static DEFINE_MUTEX(graph_lock
);
5604 struct ftrace_hash
*ftrace_graph_hash
= EMPTY_HASH
;
5605 struct ftrace_hash
*ftrace_graph_notrace_hash
= EMPTY_HASH
;
5607 enum graph_filter_type
{
5608 GRAPH_FILTER_NOTRACE
= 0,
5609 GRAPH_FILTER_FUNCTION
,
5612 #define FTRACE_GRAPH_EMPTY ((void *)1)
5614 struct ftrace_graph_data
{
5615 struct ftrace_hash
*hash
;
5616 struct ftrace_func_entry
*entry
;
5617 int idx
; /* for hash table iteration */
5618 enum graph_filter_type type
;
5619 struct ftrace_hash
*new_hash
;
5620 const struct seq_operations
*seq_ops
;
5621 struct trace_parser parser
;
5625 __g_next(struct seq_file
*m
, loff_t
*pos
)
5627 struct ftrace_graph_data
*fgd
= m
->private;
5628 struct ftrace_func_entry
*entry
= fgd
->entry
;
5629 struct hlist_head
*head
;
5630 int i
, idx
= fgd
->idx
;
5632 if (*pos
>= fgd
->hash
->count
)
5636 hlist_for_each_entry_continue(entry
, hlist
) {
5644 for (i
= idx
; i
< 1 << fgd
->hash
->size_bits
; i
++) {
5645 head
= &fgd
->hash
->buckets
[i
];
5646 hlist_for_each_entry(entry
, head
, hlist
) {
5656 g_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
5659 return __g_next(m
, pos
);
5662 static void *g_start(struct seq_file
*m
, loff_t
*pos
)
5664 struct ftrace_graph_data
*fgd
= m
->private;
5666 mutex_lock(&graph_lock
);
5668 if (fgd
->type
== GRAPH_FILTER_FUNCTION
)
5669 fgd
->hash
= rcu_dereference_protected(ftrace_graph_hash
,
5670 lockdep_is_held(&graph_lock
));
5672 fgd
->hash
= rcu_dereference_protected(ftrace_graph_notrace_hash
,
5673 lockdep_is_held(&graph_lock
));
5675 /* Nothing, tell g_show to print all functions are enabled */
5676 if (ftrace_hash_empty(fgd
->hash
) && !*pos
)
5677 return FTRACE_GRAPH_EMPTY
;
5681 return __g_next(m
, pos
);
5684 static void g_stop(struct seq_file
*m
, void *p
)
5686 mutex_unlock(&graph_lock
);
5689 static int g_show(struct seq_file
*m
, void *v
)
5691 struct ftrace_func_entry
*entry
= v
;
5696 if (entry
== FTRACE_GRAPH_EMPTY
) {
5697 struct ftrace_graph_data
*fgd
= m
->private;
5699 if (fgd
->type
== GRAPH_FILTER_FUNCTION
)
5700 seq_puts(m
, "#### all functions enabled ####\n");
5702 seq_puts(m
, "#### no functions disabled ####\n");
5706 seq_printf(m
, "%ps\n", (void *)entry
->ip
);
5711 static const struct seq_operations ftrace_graph_seq_ops
= {
5719 __ftrace_graph_open(struct inode
*inode
, struct file
*file
,
5720 struct ftrace_graph_data
*fgd
)
5723 struct ftrace_hash
*new_hash
= NULL
;
5725 ret
= security_locked_down(LOCKDOWN_TRACEFS
);
5729 if (file
->f_mode
& FMODE_WRITE
) {
5730 const int size_bits
= FTRACE_HASH_DEFAULT_BITS
;
5732 if (trace_parser_get_init(&fgd
->parser
, FTRACE_BUFF_MAX
))
5735 if (file
->f_flags
& O_TRUNC
)
5736 new_hash
= alloc_ftrace_hash(size_bits
);
5738 new_hash
= alloc_and_copy_ftrace_hash(size_bits
,
5746 if (file
->f_mode
& FMODE_READ
) {
5747 ret
= seq_open(file
, &ftrace_graph_seq_ops
);
5749 struct seq_file
*m
= file
->private_data
;
5753 free_ftrace_hash(new_hash
);
5757 file
->private_data
= fgd
;
5760 if (ret
< 0 && file
->f_mode
& FMODE_WRITE
)
5761 trace_parser_put(&fgd
->parser
);
5763 fgd
->new_hash
= new_hash
;
5766 * All uses of fgd->hash must be taken with the graph_lock
5767 * held. The graph_lock is going to be released, so force
5768 * fgd->hash to be reinitialized when it is taken again.
5776 ftrace_graph_open(struct inode
*inode
, struct file
*file
)
5778 struct ftrace_graph_data
*fgd
;
5781 if (unlikely(ftrace_disabled
))
5784 fgd
= kmalloc(sizeof(*fgd
), GFP_KERNEL
);
5788 mutex_lock(&graph_lock
);
5790 fgd
->hash
= rcu_dereference_protected(ftrace_graph_hash
,
5791 lockdep_is_held(&graph_lock
));
5792 fgd
->type
= GRAPH_FILTER_FUNCTION
;
5793 fgd
->seq_ops
= &ftrace_graph_seq_ops
;
5795 ret
= __ftrace_graph_open(inode
, file
, fgd
);
5799 mutex_unlock(&graph_lock
);
5804 ftrace_graph_notrace_open(struct inode
*inode
, struct file
*file
)
5806 struct ftrace_graph_data
*fgd
;
5809 if (unlikely(ftrace_disabled
))
5812 fgd
= kmalloc(sizeof(*fgd
), GFP_KERNEL
);
5816 mutex_lock(&graph_lock
);
5818 fgd
->hash
= rcu_dereference_protected(ftrace_graph_notrace_hash
,
5819 lockdep_is_held(&graph_lock
));
5820 fgd
->type
= GRAPH_FILTER_NOTRACE
;
5821 fgd
->seq_ops
= &ftrace_graph_seq_ops
;
5823 ret
= __ftrace_graph_open(inode
, file
, fgd
);
5827 mutex_unlock(&graph_lock
);
5832 ftrace_graph_release(struct inode
*inode
, struct file
*file
)
5834 struct ftrace_graph_data
*fgd
;
5835 struct ftrace_hash
*old_hash
, *new_hash
;
5836 struct trace_parser
*parser
;
5839 if (file
->f_mode
& FMODE_READ
) {
5840 struct seq_file
*m
= file
->private_data
;
5843 seq_release(inode
, file
);
5845 fgd
= file
->private_data
;
5849 if (file
->f_mode
& FMODE_WRITE
) {
5851 parser
= &fgd
->parser
;
5853 if (trace_parser_loaded((parser
))) {
5854 ret
= ftrace_graph_set_hash(fgd
->new_hash
,
5858 trace_parser_put(parser
);
5860 new_hash
= __ftrace_hash_move(fgd
->new_hash
);
5866 mutex_lock(&graph_lock
);
5868 if (fgd
->type
== GRAPH_FILTER_FUNCTION
) {
5869 old_hash
= rcu_dereference_protected(ftrace_graph_hash
,
5870 lockdep_is_held(&graph_lock
));
5871 rcu_assign_pointer(ftrace_graph_hash
, new_hash
);
5873 old_hash
= rcu_dereference_protected(ftrace_graph_notrace_hash
,
5874 lockdep_is_held(&graph_lock
));
5875 rcu_assign_pointer(ftrace_graph_notrace_hash
, new_hash
);
5878 mutex_unlock(&graph_lock
);
5880 /* Wait till all users are no longer using the old hash */
5883 free_ftrace_hash(old_hash
);
5887 free_ftrace_hash(fgd
->new_hash
);
5894 ftrace_graph_set_hash(struct ftrace_hash
*hash
, char *buffer
)
5896 struct ftrace_glob func_g
;
5897 struct dyn_ftrace
*rec
;
5898 struct ftrace_page
*pg
;
5899 struct ftrace_func_entry
*entry
;
5904 func_g
.type
= filter_parse_regex(buffer
, strlen(buffer
),
5905 &func_g
.search
, ¬);
5907 func_g
.len
= strlen(func_g
.search
);
5909 mutex_lock(&ftrace_lock
);
5911 if (unlikely(ftrace_disabled
)) {
5912 mutex_unlock(&ftrace_lock
);
5916 do_for_each_ftrace_rec(pg
, rec
) {
5918 if (rec
->flags
& FTRACE_FL_DISABLED
)
5921 if (ftrace_match_record(rec
, &func_g
, NULL
, 0)) {
5922 entry
= ftrace_lookup_ip(hash
, rec
->ip
);
5929 if (add_hash_entry(hash
, rec
->ip
) < 0)
5933 free_hash_entry(hash
, entry
);
5938 } while_for_each_ftrace_rec();
5940 mutex_unlock(&ftrace_lock
);
5949 ftrace_graph_write(struct file
*file
, const char __user
*ubuf
,
5950 size_t cnt
, loff_t
*ppos
)
5952 ssize_t read
, ret
= 0;
5953 struct ftrace_graph_data
*fgd
= file
->private_data
;
5954 struct trace_parser
*parser
;
5959 /* Read mode uses seq functions */
5960 if (file
->f_mode
& FMODE_READ
) {
5961 struct seq_file
*m
= file
->private_data
;
5965 parser
= &fgd
->parser
;
5967 read
= trace_get_user(parser
, ubuf
, cnt
, ppos
);
5969 if (read
>= 0 && trace_parser_loaded(parser
) &&
5970 !trace_parser_cont(parser
)) {
5972 ret
= ftrace_graph_set_hash(fgd
->new_hash
,
5974 trace_parser_clear(parser
);
5983 static const struct file_operations ftrace_graph_fops
= {
5984 .open
= ftrace_graph_open
,
5986 .write
= ftrace_graph_write
,
5987 .llseek
= tracing_lseek
,
5988 .release
= ftrace_graph_release
,
5991 static const struct file_operations ftrace_graph_notrace_fops
= {
5992 .open
= ftrace_graph_notrace_open
,
5994 .write
= ftrace_graph_write
,
5995 .llseek
= tracing_lseek
,
5996 .release
= ftrace_graph_release
,
5998 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6000 void ftrace_create_filter_files(struct ftrace_ops
*ops
,
6001 struct dentry
*parent
)
6004 trace_create_file("set_ftrace_filter", 0644, parent
,
6005 ops
, &ftrace_filter_fops
);
6007 trace_create_file("set_ftrace_notrace", 0644, parent
,
6008 ops
, &ftrace_notrace_fops
);
6012 * The name "destroy_filter_files" is really a misnomer. Although
6013 * in the future, it may actually delete the files, but this is
6014 * really intended to make sure the ops passed in are disabled
6015 * and that when this function returns, the caller is free to
6018 * The "destroy" name is only to match the "create" name that this
6019 * should be paired with.
6021 void ftrace_destroy_filter_files(struct ftrace_ops
*ops
)
6023 mutex_lock(&ftrace_lock
);
6024 if (ops
->flags
& FTRACE_OPS_FL_ENABLED
)
6025 ftrace_shutdown(ops
, 0);
6026 ops
->flags
|= FTRACE_OPS_FL_DELETED
;
6027 ftrace_free_filter(ops
);
6028 mutex_unlock(&ftrace_lock
);
6031 static __init
int ftrace_init_dyn_tracefs(struct dentry
*d_tracer
)
6034 trace_create_file("available_filter_functions", 0444,
6035 d_tracer
, NULL
, &ftrace_avail_fops
);
6037 trace_create_file("enabled_functions", 0444,
6038 d_tracer
, NULL
, &ftrace_enabled_fops
);
6040 ftrace_create_filter_files(&global_ops
, d_tracer
);
6042 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
6043 trace_create_file("set_graph_function", 0644, d_tracer
,
6045 &ftrace_graph_fops
);
6046 trace_create_file("set_graph_notrace", 0644, d_tracer
,
6048 &ftrace_graph_notrace_fops
);
6049 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6054 static int ftrace_cmp_ips(const void *a
, const void *b
)
6056 const unsigned long *ipa
= a
;
6057 const unsigned long *ipb
= b
;
6066 static int ftrace_process_locs(struct module
*mod
,
6067 unsigned long *start
,
6070 struct ftrace_page
*start_pg
;
6071 struct ftrace_page
*pg
;
6072 struct dyn_ftrace
*rec
;
6073 unsigned long count
;
6076 unsigned long flags
= 0; /* Shut up gcc */
6079 count
= end
- start
;
6084 sort(start
, count
, sizeof(*start
),
6085 ftrace_cmp_ips
, NULL
);
6087 start_pg
= ftrace_allocate_pages(count
);
6091 mutex_lock(&ftrace_lock
);
6094 * Core and each module needs their own pages, as
6095 * modules will free them when they are removed.
6096 * Force a new page to be allocated for modules.
6099 WARN_ON(ftrace_pages
|| ftrace_pages_start
);
6100 /* First initialization */
6101 ftrace_pages
= ftrace_pages_start
= start_pg
;
6106 if (WARN_ON(ftrace_pages
->next
)) {
6107 /* Hmm, we have free pages? */
6108 while (ftrace_pages
->next
)
6109 ftrace_pages
= ftrace_pages
->next
;
6112 ftrace_pages
->next
= start_pg
;
6118 addr
= ftrace_call_adjust(*p
++);
6120 * Some architecture linkers will pad between
6121 * the different mcount_loc sections of different
6122 * object files to satisfy alignments.
6123 * Skip any NULL pointers.
6128 if (pg
->index
== pg
->size
) {
6129 /* We should have allocated enough */
6130 if (WARN_ON(!pg
->next
))
6135 rec
= &pg
->records
[pg
->index
++];
6139 /* We should have used all pages */
6142 /* Assign the last page to ftrace_pages */
6146 * We only need to disable interrupts on start up
6147 * because we are modifying code that an interrupt
6148 * may execute, and the modification is not atomic.
6149 * But for modules, nothing runs the code we modify
6150 * until we are finished with it, and there's no
6151 * reason to cause large interrupt latencies while we do it.
6154 local_irq_save(flags
);
6155 ftrace_update_code(mod
, start_pg
);
6157 local_irq_restore(flags
);
6160 mutex_unlock(&ftrace_lock
);
6165 struct ftrace_mod_func
{
6166 struct list_head list
;
6172 struct ftrace_mod_map
{
6173 struct rcu_head rcu
;
6174 struct list_head list
;
6176 unsigned long start_addr
;
6177 unsigned long end_addr
;
6178 struct list_head funcs
;
6179 unsigned int num_funcs
;
6182 #ifdef CONFIG_MODULES
6184 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
6186 static LIST_HEAD(ftrace_mod_maps
);
6188 static int referenced_filters(struct dyn_ftrace
*rec
)
6190 struct ftrace_ops
*ops
;
6193 for (ops
= ftrace_ops_list
; ops
!= &ftrace_list_end
; ops
= ops
->next
) {
6194 if (ops_references_rec(ops
, rec
))
6202 clear_mod_from_hash(struct ftrace_page
*pg
, struct ftrace_hash
*hash
)
6204 struct ftrace_func_entry
*entry
;
6205 struct dyn_ftrace
*rec
;
6208 if (ftrace_hash_empty(hash
))
6211 for (i
= 0; i
< pg
->index
; i
++) {
6212 rec
= &pg
->records
[i
];
6213 entry
= __ftrace_lookup_ip(hash
, rec
->ip
);
6215 * Do not allow this rec to match again.
6216 * Yeah, it may waste some memory, but will be removed
6217 * if/when the hash is modified again.
6224 /* Clear any records from hashs */
6225 static void clear_mod_from_hashes(struct ftrace_page
*pg
)
6227 struct trace_array
*tr
;
6229 mutex_lock(&trace_types_lock
);
6230 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
6231 if (!tr
->ops
|| !tr
->ops
->func_hash
)
6233 mutex_lock(&tr
->ops
->func_hash
->regex_lock
);
6234 clear_mod_from_hash(pg
, tr
->ops
->func_hash
->filter_hash
);
6235 clear_mod_from_hash(pg
, tr
->ops
->func_hash
->notrace_hash
);
6236 mutex_unlock(&tr
->ops
->func_hash
->regex_lock
);
6238 mutex_unlock(&trace_types_lock
);
6241 static void ftrace_free_mod_map(struct rcu_head
*rcu
)
6243 struct ftrace_mod_map
*mod_map
= container_of(rcu
, struct ftrace_mod_map
, rcu
);
6244 struct ftrace_mod_func
*mod_func
;
6245 struct ftrace_mod_func
*n
;
6247 /* All the contents of mod_map are now not visible to readers */
6248 list_for_each_entry_safe(mod_func
, n
, &mod_map
->funcs
, list
) {
6249 kfree(mod_func
->name
);
6250 list_del(&mod_func
->list
);
6257 void ftrace_release_mod(struct module
*mod
)
6259 struct ftrace_mod_map
*mod_map
;
6260 struct ftrace_mod_map
*n
;
6261 struct dyn_ftrace
*rec
;
6262 struct ftrace_page
**last_pg
;
6263 struct ftrace_page
*tmp_page
= NULL
;
6264 struct ftrace_page
*pg
;
6267 mutex_lock(&ftrace_lock
);
6269 if (ftrace_disabled
)
6272 list_for_each_entry_safe(mod_map
, n
, &ftrace_mod_maps
, list
) {
6273 if (mod_map
->mod
== mod
) {
6274 list_del_rcu(&mod_map
->list
);
6275 call_rcu(&mod_map
->rcu
, ftrace_free_mod_map
);
6281 * Each module has its own ftrace_pages, remove
6282 * them from the list.
6284 last_pg
= &ftrace_pages_start
;
6285 for (pg
= ftrace_pages_start
; pg
; pg
= *last_pg
) {
6286 rec
= &pg
->records
[0];
6287 if (within_module_core(rec
->ip
, mod
) ||
6288 within_module_init(rec
->ip
, mod
)) {
6290 * As core pages are first, the first
6291 * page should never be a module page.
6293 if (WARN_ON(pg
== ftrace_pages_start
))
6296 /* Check if we are deleting the last page */
6297 if (pg
== ftrace_pages
)
6298 ftrace_pages
= next_to_ftrace_page(last_pg
);
6300 ftrace_update_tot_cnt
-= pg
->index
;
6301 *last_pg
= pg
->next
;
6303 pg
->next
= tmp_page
;
6306 last_pg
= &pg
->next
;
6309 mutex_unlock(&ftrace_lock
);
6311 for (pg
= tmp_page
; pg
; pg
= tmp_page
) {
6313 /* Needs to be called outside of ftrace_lock */
6314 clear_mod_from_hashes(pg
);
6316 order
= get_count_order(pg
->size
/ ENTRIES_PER_PAGE
);
6317 free_pages((unsigned long)pg
->records
, order
);
6318 tmp_page
= pg
->next
;
6320 ftrace_number_of_pages
-= 1 << order
;
6321 ftrace_number_of_groups
--;
6325 void ftrace_module_enable(struct module
*mod
)
6327 struct dyn_ftrace
*rec
;
6328 struct ftrace_page
*pg
;
6330 mutex_lock(&ftrace_lock
);
6332 if (ftrace_disabled
)
6336 * If the tracing is enabled, go ahead and enable the record.
6338 * The reason not to enable the record immediately is the
6339 * inherent check of ftrace_make_nop/ftrace_make_call for
6340 * correct previous instructions. Making first the NOP
6341 * conversion puts the module to the correct state, thus
6342 * passing the ftrace_make_call check.
6344 * We also delay this to after the module code already set the
6345 * text to read-only, as we now need to set it back to read-write
6346 * so that we can modify the text.
6348 if (ftrace_start_up
)
6349 ftrace_arch_code_modify_prepare();
6351 do_for_each_ftrace_rec(pg
, rec
) {
6354 * do_for_each_ftrace_rec() is a double loop.
6355 * module text shares the pg. If a record is
6356 * not part of this module, then skip this pg,
6357 * which the "break" will do.
6359 if (!within_module_core(rec
->ip
, mod
) &&
6360 !within_module_init(rec
->ip
, mod
))
6366 * When adding a module, we need to check if tracers are
6367 * currently enabled and if they are, and can trace this record,
6368 * we need to enable the module functions as well as update the
6369 * reference counts for those function records.
6371 if (ftrace_start_up
)
6372 cnt
+= referenced_filters(rec
);
6374 /* This clears FTRACE_FL_DISABLED */
6377 if (ftrace_start_up
&& cnt
) {
6378 int failed
= __ftrace_replace_code(rec
, 1);
6380 ftrace_bug(failed
, rec
);
6385 } while_for_each_ftrace_rec();
6388 if (ftrace_start_up
)
6389 ftrace_arch_code_modify_post_process();
6392 mutex_unlock(&ftrace_lock
);
6394 process_cached_mods(mod
->name
);
6397 void ftrace_module_init(struct module
*mod
)
6399 if (ftrace_disabled
|| !mod
->num_ftrace_callsites
)
6402 ftrace_process_locs(mod
, mod
->ftrace_callsites
,
6403 mod
->ftrace_callsites
+ mod
->num_ftrace_callsites
);
6406 static void save_ftrace_mod_rec(struct ftrace_mod_map
*mod_map
,
6407 struct dyn_ftrace
*rec
)
6409 struct ftrace_mod_func
*mod_func
;
6410 unsigned long symsize
;
6411 unsigned long offset
;
6412 char str
[KSYM_SYMBOL_LEN
];
6416 ret
= kallsyms_lookup(rec
->ip
, &symsize
, &offset
, &modname
, str
);
6420 mod_func
= kmalloc(sizeof(*mod_func
), GFP_KERNEL
);
6424 mod_func
->name
= kstrdup(str
, GFP_KERNEL
);
6425 if (!mod_func
->name
) {
6430 mod_func
->ip
= rec
->ip
- offset
;
6431 mod_func
->size
= symsize
;
6433 mod_map
->num_funcs
++;
6435 list_add_rcu(&mod_func
->list
, &mod_map
->funcs
);
6438 static struct ftrace_mod_map
*
6439 allocate_ftrace_mod_map(struct module
*mod
,
6440 unsigned long start
, unsigned long end
)
6442 struct ftrace_mod_map
*mod_map
;
6444 mod_map
= kmalloc(sizeof(*mod_map
), GFP_KERNEL
);
6449 mod_map
->start_addr
= start
;
6450 mod_map
->end_addr
= end
;
6451 mod_map
->num_funcs
= 0;
6453 INIT_LIST_HEAD_RCU(&mod_map
->funcs
);
6455 list_add_rcu(&mod_map
->list
, &ftrace_mod_maps
);
6461 ftrace_func_address_lookup(struct ftrace_mod_map
*mod_map
,
6462 unsigned long addr
, unsigned long *size
,
6463 unsigned long *off
, char *sym
)
6465 struct ftrace_mod_func
*found_func
= NULL
;
6466 struct ftrace_mod_func
*mod_func
;
6468 list_for_each_entry_rcu(mod_func
, &mod_map
->funcs
, list
) {
6469 if (addr
>= mod_func
->ip
&&
6470 addr
< mod_func
->ip
+ mod_func
->size
) {
6471 found_func
= mod_func
;
6478 *size
= found_func
->size
;
6480 *off
= addr
- found_func
->ip
;
6482 strlcpy(sym
, found_func
->name
, KSYM_NAME_LEN
);
6484 return found_func
->name
;
6491 ftrace_mod_address_lookup(unsigned long addr
, unsigned long *size
,
6492 unsigned long *off
, char **modname
, char *sym
)
6494 struct ftrace_mod_map
*mod_map
;
6495 const char *ret
= NULL
;
6497 /* mod_map is freed via call_rcu() */
6499 list_for_each_entry_rcu(mod_map
, &ftrace_mod_maps
, list
) {
6500 ret
= ftrace_func_address_lookup(mod_map
, addr
, size
, off
, sym
);
6503 *modname
= mod_map
->mod
->name
;
6512 int ftrace_mod_get_kallsym(unsigned int symnum
, unsigned long *value
,
6513 char *type
, char *name
,
6514 char *module_name
, int *exported
)
6516 struct ftrace_mod_map
*mod_map
;
6517 struct ftrace_mod_func
*mod_func
;
6520 list_for_each_entry_rcu(mod_map
, &ftrace_mod_maps
, list
) {
6522 if (symnum
>= mod_map
->num_funcs
) {
6523 symnum
-= mod_map
->num_funcs
;
6527 list_for_each_entry_rcu(mod_func
, &mod_map
->funcs
, list
) {
6533 *value
= mod_func
->ip
;
6535 strlcpy(name
, mod_func
->name
, KSYM_NAME_LEN
);
6536 strlcpy(module_name
, mod_map
->mod
->name
, MODULE_NAME_LEN
);
6549 static void save_ftrace_mod_rec(struct ftrace_mod_map
*mod_map
,
6550 struct dyn_ftrace
*rec
) { }
6551 static inline struct ftrace_mod_map
*
6552 allocate_ftrace_mod_map(struct module
*mod
,
6553 unsigned long start
, unsigned long end
)
6557 #endif /* CONFIG_MODULES */
6559 struct ftrace_init_func
{
6560 struct list_head list
;
6564 /* Clear any init ips from hashes */
6566 clear_func_from_hash(struct ftrace_init_func
*func
, struct ftrace_hash
*hash
)
6568 struct ftrace_func_entry
*entry
;
6570 entry
= ftrace_lookup_ip(hash
, func
->ip
);
6572 * Do not allow this rec to match again.
6573 * Yeah, it may waste some memory, but will be removed
6574 * if/when the hash is modified again.
6581 clear_func_from_hashes(struct ftrace_init_func
*func
)
6583 struct trace_array
*tr
;
6585 mutex_lock(&trace_types_lock
);
6586 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
6587 if (!tr
->ops
|| !tr
->ops
->func_hash
)
6589 mutex_lock(&tr
->ops
->func_hash
->regex_lock
);
6590 clear_func_from_hash(func
, tr
->ops
->func_hash
->filter_hash
);
6591 clear_func_from_hash(func
, tr
->ops
->func_hash
->notrace_hash
);
6592 mutex_unlock(&tr
->ops
->func_hash
->regex_lock
);
6594 mutex_unlock(&trace_types_lock
);
6597 static void add_to_clear_hash_list(struct list_head
*clear_list
,
6598 struct dyn_ftrace
*rec
)
6600 struct ftrace_init_func
*func
;
6602 func
= kmalloc(sizeof(*func
), GFP_KERNEL
);
6604 WARN_ONCE(1, "alloc failure, ftrace filter could be stale\n");
6609 list_add(&func
->list
, clear_list
);
6612 void ftrace_free_mem(struct module
*mod
, void *start_ptr
, void *end_ptr
)
6614 unsigned long start
= (unsigned long)(start_ptr
);
6615 unsigned long end
= (unsigned long)(end_ptr
);
6616 struct ftrace_page
**last_pg
= &ftrace_pages_start
;
6617 struct ftrace_page
*pg
;
6618 struct dyn_ftrace
*rec
;
6619 struct dyn_ftrace key
;
6620 struct ftrace_mod_map
*mod_map
= NULL
;
6621 struct ftrace_init_func
*func
, *func_next
;
6622 struct list_head clear_hash
;
6625 INIT_LIST_HEAD(&clear_hash
);
6628 key
.flags
= end
; /* overload flags, as it is unsigned long */
6630 mutex_lock(&ftrace_lock
);
6633 * If we are freeing module init memory, then check if
6634 * any tracer is active. If so, we need to save a mapping of
6635 * the module functions being freed with the address.
6637 if (mod
&& ftrace_ops_list
!= &ftrace_list_end
)
6638 mod_map
= allocate_ftrace_mod_map(mod
, start
, end
);
6640 for (pg
= ftrace_pages_start
; pg
; last_pg
= &pg
->next
, pg
= *last_pg
) {
6641 if (end
< pg
->records
[0].ip
||
6642 start
>= (pg
->records
[pg
->index
- 1].ip
+ MCOUNT_INSN_SIZE
))
6645 rec
= bsearch(&key
, pg
->records
, pg
->index
,
6646 sizeof(struct dyn_ftrace
),
6651 /* rec will be cleared from hashes after ftrace_lock unlock */
6652 add_to_clear_hash_list(&clear_hash
, rec
);
6655 save_ftrace_mod_rec(mod_map
, rec
);
6658 ftrace_update_tot_cnt
--;
6660 *last_pg
= pg
->next
;
6661 order
= get_count_order(pg
->size
/ ENTRIES_PER_PAGE
);
6662 free_pages((unsigned long)pg
->records
, order
);
6663 ftrace_number_of_pages
-= 1 << order
;
6664 ftrace_number_of_groups
--;
6666 pg
= container_of(last_pg
, struct ftrace_page
, next
);
6671 memmove(rec
, rec
+ 1,
6672 (pg
->index
- (rec
- pg
->records
)) * sizeof(*rec
));
6673 /* More than one function may be in this block */
6676 mutex_unlock(&ftrace_lock
);
6678 list_for_each_entry_safe(func
, func_next
, &clear_hash
, list
) {
6679 clear_func_from_hashes(func
);
6684 void __init
ftrace_free_init_mem(void)
6686 void *start
= (void *)(&__init_begin
);
6687 void *end
= (void *)(&__init_end
);
6689 ftrace_free_mem(NULL
, start
, end
);
6692 void __init
ftrace_init(void)
6694 extern unsigned long __start_mcount_loc
[];
6695 extern unsigned long __stop_mcount_loc
[];
6696 unsigned long count
, flags
;
6699 local_irq_save(flags
);
6700 ret
= ftrace_dyn_arch_init();
6701 local_irq_restore(flags
);
6705 count
= __stop_mcount_loc
- __start_mcount_loc
;
6707 pr_info("ftrace: No functions to be traced?\n");
6711 pr_info("ftrace: allocating %ld entries in %ld pages\n",
6712 count
, count
/ ENTRIES_PER_PAGE
+ 1);
6714 last_ftrace_enabled
= ftrace_enabled
= 1;
6716 ret
= ftrace_process_locs(NULL
,
6720 pr_info("ftrace: allocated %ld pages with %ld groups\n",
6721 ftrace_number_of_pages
, ftrace_number_of_groups
);
6723 set_ftrace_early_filters();
6727 ftrace_disabled
= 1;
6730 /* Do nothing if arch does not support this */
6731 void __weak
arch_ftrace_update_trampoline(struct ftrace_ops
*ops
)
6735 static void ftrace_update_trampoline(struct ftrace_ops
*ops
)
6737 arch_ftrace_update_trampoline(ops
);
6740 void ftrace_init_trace_array(struct trace_array
*tr
)
6742 INIT_LIST_HEAD(&tr
->func_probes
);
6743 INIT_LIST_HEAD(&tr
->mod_trace
);
6744 INIT_LIST_HEAD(&tr
->mod_notrace
);
6748 struct ftrace_ops global_ops
= {
6749 .func
= ftrace_stub
,
6750 .flags
= FTRACE_OPS_FL_RECURSION_SAFE
|
6751 FTRACE_OPS_FL_INITIALIZED
|
6755 static int __init
ftrace_nodyn_init(void)
6760 core_initcall(ftrace_nodyn_init
);
6762 static inline int ftrace_init_dyn_tracefs(struct dentry
*d_tracer
) { return 0; }
6763 static inline void ftrace_startup_enable(int command
) { }
6764 static inline void ftrace_startup_all(int command
) { }
6766 # define ftrace_startup_sysctl() do { } while (0)
6767 # define ftrace_shutdown_sysctl() do { } while (0)
6769 static void ftrace_update_trampoline(struct ftrace_ops
*ops
)
6773 #endif /* CONFIG_DYNAMIC_FTRACE */
6775 __init
void ftrace_init_global_array_ops(struct trace_array
*tr
)
6777 tr
->ops
= &global_ops
;
6778 tr
->ops
->private = tr
;
6779 ftrace_init_trace_array(tr
);
6782 void ftrace_init_array_ops(struct trace_array
*tr
, ftrace_func_t func
)
6784 /* If we filter on pids, update to use the pid function */
6785 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
) {
6786 if (WARN_ON(tr
->ops
->func
!= ftrace_stub
))
6787 printk("ftrace ops had %pS for function\n",
6790 tr
->ops
->func
= func
;
6791 tr
->ops
->private = tr
;
6794 void ftrace_reset_array_ops(struct trace_array
*tr
)
6796 tr
->ops
->func
= ftrace_stub
;
6799 static nokprobe_inline
void
6800 __ftrace_ops_list_func(unsigned long ip
, unsigned long parent_ip
,
6801 struct ftrace_ops
*ignored
, struct pt_regs
*regs
)
6803 struct ftrace_ops
*op
;
6806 bit
= trace_test_and_set_recursion(TRACE_LIST_START
, TRACE_LIST_MAX
);
6811 * Some of the ops may be dynamically allocated,
6812 * they must be freed after a synchronize_rcu().
6814 preempt_disable_notrace();
6816 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
6817 /* Stub functions don't need to be called nor tested */
6818 if (op
->flags
& FTRACE_OPS_FL_STUB
)
6821 * Check the following for each ops before calling their func:
6822 * if RCU flag is set, then rcu_is_watching() must be true
6823 * if PER_CPU is set, then ftrace_function_local_disable()
6825 * Otherwise test if the ip matches the ops filter
6827 * If any of the above fails then the op->func() is not executed.
6829 if ((!(op
->flags
& FTRACE_OPS_FL_RCU
) || rcu_is_watching()) &&
6830 ftrace_ops_test(op
, ip
, regs
)) {
6831 if (FTRACE_WARN_ON(!op
->func
)) {
6832 pr_warn("op=%p %pS\n", op
, op
);
6835 op
->func(ip
, parent_ip
, op
, regs
);
6837 } while_for_each_ftrace_op(op
);
6839 preempt_enable_notrace();
6840 trace_clear_recursion(bit
);
6844 * Some archs only support passing ip and parent_ip. Even though
6845 * the list function ignores the op parameter, we do not want any
6846 * C side effects, where a function is called without the caller
6847 * sending a third parameter.
6848 * Archs are to support both the regs and ftrace_ops at the same time.
6849 * If they support ftrace_ops, it is assumed they support regs.
6850 * If call backs want to use regs, they must either check for regs
6851 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
6852 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
6853 * An architecture can pass partial regs with ftrace_ops and still
6854 * set the ARCH_SUPPORTS_FTRACE_OPS.
6856 #if ARCH_SUPPORTS_FTRACE_OPS
6857 static void ftrace_ops_list_func(unsigned long ip
, unsigned long parent_ip
,
6858 struct ftrace_ops
*op
, struct pt_regs
*regs
)
6860 __ftrace_ops_list_func(ip
, parent_ip
, NULL
, regs
);
6862 NOKPROBE_SYMBOL(ftrace_ops_list_func
);
6864 static void ftrace_ops_no_ops(unsigned long ip
, unsigned long parent_ip
)
6866 __ftrace_ops_list_func(ip
, parent_ip
, NULL
, NULL
);
6868 NOKPROBE_SYMBOL(ftrace_ops_no_ops
);
6872 * If there's only one function registered but it does not support
6873 * recursion, needs RCU protection and/or requires per cpu handling, then
6874 * this function will be called by the mcount trampoline.
6876 static void ftrace_ops_assist_func(unsigned long ip
, unsigned long parent_ip
,
6877 struct ftrace_ops
*op
, struct pt_regs
*regs
)
6881 if ((op
->flags
& FTRACE_OPS_FL_RCU
) && !rcu_is_watching())
6884 bit
= trace_test_and_set_recursion(TRACE_LIST_START
, TRACE_LIST_MAX
);
6888 preempt_disable_notrace();
6890 op
->func(ip
, parent_ip
, op
, regs
);
6892 preempt_enable_notrace();
6893 trace_clear_recursion(bit
);
6895 NOKPROBE_SYMBOL(ftrace_ops_assist_func
);
6898 * ftrace_ops_get_func - get the function a trampoline should call
6899 * @ops: the ops to get the function for
6901 * Normally the mcount trampoline will call the ops->func, but there
6902 * are times that it should not. For example, if the ops does not
6903 * have its own recursion protection, then it should call the
6904 * ftrace_ops_assist_func() instead.
6906 * Returns the function that the trampoline should call for @ops.
6908 ftrace_func_t
ftrace_ops_get_func(struct ftrace_ops
*ops
)
6911 * If the function does not handle recursion, needs to be RCU safe,
6912 * or does per cpu logic, then we need to call the assist handler.
6914 if (!(ops
->flags
& FTRACE_OPS_FL_RECURSION_SAFE
) ||
6915 ops
->flags
& FTRACE_OPS_FL_RCU
)
6916 return ftrace_ops_assist_func
;
6922 ftrace_filter_pid_sched_switch_probe(void *data
, bool preempt
,
6923 struct task_struct
*prev
, struct task_struct
*next
)
6925 struct trace_array
*tr
= data
;
6926 struct trace_pid_list
*pid_list
;
6928 pid_list
= rcu_dereference_sched(tr
->function_pids
);
6930 this_cpu_write(tr
->trace_buffer
.data
->ftrace_ignore_pid
,
6931 trace_ignore_this_task(pid_list
, next
));
6935 ftrace_pid_follow_sched_process_fork(void *data
,
6936 struct task_struct
*self
,
6937 struct task_struct
*task
)
6939 struct trace_pid_list
*pid_list
;
6940 struct trace_array
*tr
= data
;
6942 pid_list
= rcu_dereference_sched(tr
->function_pids
);
6943 trace_filter_add_remove_task(pid_list
, self
, task
);
6947 ftrace_pid_follow_sched_process_exit(void *data
, struct task_struct
*task
)
6949 struct trace_pid_list
*pid_list
;
6950 struct trace_array
*tr
= data
;
6952 pid_list
= rcu_dereference_sched(tr
->function_pids
);
6953 trace_filter_add_remove_task(pid_list
, NULL
, task
);
6956 void ftrace_pid_follow_fork(struct trace_array
*tr
, bool enable
)
6959 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork
,
6961 register_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit
,
6964 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork
,
6966 unregister_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit
,
6971 static void clear_ftrace_pids(struct trace_array
*tr
)
6973 struct trace_pid_list
*pid_list
;
6976 pid_list
= rcu_dereference_protected(tr
->function_pids
,
6977 lockdep_is_held(&ftrace_lock
));
6981 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe
, tr
);
6983 for_each_possible_cpu(cpu
)
6984 per_cpu_ptr(tr
->trace_buffer
.data
, cpu
)->ftrace_ignore_pid
= false;
6986 rcu_assign_pointer(tr
->function_pids
, NULL
);
6988 /* Wait till all users are no longer using pid filtering */
6991 trace_free_pid_list(pid_list
);
6994 void ftrace_clear_pids(struct trace_array
*tr
)
6996 mutex_lock(&ftrace_lock
);
6998 clear_ftrace_pids(tr
);
7000 mutex_unlock(&ftrace_lock
);
7003 static void ftrace_pid_reset(struct trace_array
*tr
)
7005 mutex_lock(&ftrace_lock
);
7006 clear_ftrace_pids(tr
);
7008 ftrace_update_pid_func();
7009 ftrace_startup_all(0);
7011 mutex_unlock(&ftrace_lock
);
7014 /* Greater than any max PID */
7015 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
7017 static void *fpid_start(struct seq_file
*m
, loff_t
*pos
)
7020 struct trace_pid_list
*pid_list
;
7021 struct trace_array
*tr
= m
->private;
7023 mutex_lock(&ftrace_lock
);
7024 rcu_read_lock_sched();
7026 pid_list
= rcu_dereference_sched(tr
->function_pids
);
7029 return !(*pos
) ? FTRACE_NO_PIDS
: NULL
;
7031 return trace_pid_start(pid_list
, pos
);
7034 static void *fpid_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
7036 struct trace_array
*tr
= m
->private;
7037 struct trace_pid_list
*pid_list
= rcu_dereference_sched(tr
->function_pids
);
7039 if (v
== FTRACE_NO_PIDS
)
7042 return trace_pid_next(pid_list
, v
, pos
);
7045 static void fpid_stop(struct seq_file
*m
, void *p
)
7048 rcu_read_unlock_sched();
7049 mutex_unlock(&ftrace_lock
);
7052 static int fpid_show(struct seq_file
*m
, void *v
)
7054 if (v
== FTRACE_NO_PIDS
) {
7055 seq_puts(m
, "no pid\n");
7059 return trace_pid_show(m
, v
);
7062 static const struct seq_operations ftrace_pid_sops
= {
7063 .start
= fpid_start
,
7070 ftrace_pid_open(struct inode
*inode
, struct file
*file
)
7072 struct trace_array
*tr
= inode
->i_private
;
7076 ret
= tracing_check_open_get_tr(tr
);
7080 if ((file
->f_mode
& FMODE_WRITE
) &&
7081 (file
->f_flags
& O_TRUNC
))
7082 ftrace_pid_reset(tr
);
7084 ret
= seq_open(file
, &ftrace_pid_sops
);
7086 trace_array_put(tr
);
7088 m
= file
->private_data
;
7089 /* copy tr over to seq ops */
7096 static void ignore_task_cpu(void *data
)
7098 struct trace_array
*tr
= data
;
7099 struct trace_pid_list
*pid_list
;
7102 * This function is called by on_each_cpu() while the
7103 * event_mutex is held.
7105 pid_list
= rcu_dereference_protected(tr
->function_pids
,
7106 mutex_is_locked(&ftrace_lock
));
7108 this_cpu_write(tr
->trace_buffer
.data
->ftrace_ignore_pid
,
7109 trace_ignore_this_task(pid_list
, current
));
7113 ftrace_pid_write(struct file
*filp
, const char __user
*ubuf
,
7114 size_t cnt
, loff_t
*ppos
)
7116 struct seq_file
*m
= filp
->private_data
;
7117 struct trace_array
*tr
= m
->private;
7118 struct trace_pid_list
*filtered_pids
= NULL
;
7119 struct trace_pid_list
*pid_list
;
7125 mutex_lock(&ftrace_lock
);
7127 filtered_pids
= rcu_dereference_protected(tr
->function_pids
,
7128 lockdep_is_held(&ftrace_lock
));
7130 ret
= trace_pid_write(filtered_pids
, &pid_list
, ubuf
, cnt
);
7134 rcu_assign_pointer(tr
->function_pids
, pid_list
);
7136 if (filtered_pids
) {
7138 trace_free_pid_list(filtered_pids
);
7139 } else if (pid_list
) {
7140 /* Register a probe to set whether to ignore the tracing of a task */
7141 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe
, tr
);
7145 * Ignoring of pids is done at task switch. But we have to
7146 * check for those tasks that are currently running.
7147 * Always do this in case a pid was appended or removed.
7149 on_each_cpu(ignore_task_cpu
, tr
, 1);
7151 ftrace_update_pid_func();
7152 ftrace_startup_all(0);
7154 mutex_unlock(&ftrace_lock
);
7163 ftrace_pid_release(struct inode
*inode
, struct file
*file
)
7165 struct trace_array
*tr
= inode
->i_private
;
7167 trace_array_put(tr
);
7169 return seq_release(inode
, file
);
7172 static const struct file_operations ftrace_pid_fops
= {
7173 .open
= ftrace_pid_open
,
7174 .write
= ftrace_pid_write
,
7176 .llseek
= tracing_lseek
,
7177 .release
= ftrace_pid_release
,
7180 void ftrace_init_tracefs(struct trace_array
*tr
, struct dentry
*d_tracer
)
7182 trace_create_file("set_ftrace_pid", 0644, d_tracer
,
7183 tr
, &ftrace_pid_fops
);
7186 void __init
ftrace_init_tracefs_toplevel(struct trace_array
*tr
,
7187 struct dentry
*d_tracer
)
7189 /* Only the top level directory has the dyn_tracefs and profile */
7190 WARN_ON(!(tr
->flags
& TRACE_ARRAY_FL_GLOBAL
));
7192 ftrace_init_dyn_tracefs(d_tracer
);
7193 ftrace_profile_tracefs(d_tracer
);
7197 * ftrace_kill - kill ftrace
7199 * This function should be used by panic code. It stops ftrace
7200 * but in a not so nice way. If you need to simply kill ftrace
7201 * from a non-atomic section, use ftrace_kill.
7203 void ftrace_kill(void)
7205 ftrace_disabled
= 1;
7207 ftrace_trace_function
= ftrace_stub
;
7211 * Test if ftrace is dead or not.
7213 int ftrace_is_dead(void)
7215 return ftrace_disabled
;
7219 * register_ftrace_function - register a function for profiling
7220 * @ops - ops structure that holds the function for profiling.
7222 * Register a function to be called by all functions in the
7225 * Note: @ops->func and all the functions it calls must be labeled
7226 * with "notrace", otherwise it will go into a
7229 int register_ftrace_function(struct ftrace_ops
*ops
)
7233 ftrace_ops_init(ops
);
7235 mutex_lock(&ftrace_lock
);
7237 ret
= ftrace_startup(ops
, 0);
7239 mutex_unlock(&ftrace_lock
);
7243 EXPORT_SYMBOL_GPL(register_ftrace_function
);
7246 * unregister_ftrace_function - unregister a function for profiling.
7247 * @ops - ops structure that holds the function to unregister
7249 * Unregister a function that was added to be called by ftrace profiling.
7251 int unregister_ftrace_function(struct ftrace_ops
*ops
)
7255 mutex_lock(&ftrace_lock
);
7256 ret
= ftrace_shutdown(ops
, 0);
7257 mutex_unlock(&ftrace_lock
);
7261 EXPORT_SYMBOL_GPL(unregister_ftrace_function
);
7263 static bool is_permanent_ops_registered(void)
7265 struct ftrace_ops
*op
;
7267 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
7268 if (op
->flags
& FTRACE_OPS_FL_PERMANENT
)
7270 } while_for_each_ftrace_op(op
);
7276 ftrace_enable_sysctl(struct ctl_table
*table
, int write
,
7277 void __user
*buffer
, size_t *lenp
,
7282 mutex_lock(&ftrace_lock
);
7284 if (unlikely(ftrace_disabled
))
7287 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7289 if (ret
|| !write
|| (last_ftrace_enabled
== !!ftrace_enabled
))
7292 if (ftrace_enabled
) {
7294 /* we are starting ftrace again */
7295 if (rcu_dereference_protected(ftrace_ops_list
,
7296 lockdep_is_held(&ftrace_lock
)) != &ftrace_list_end
)
7297 update_ftrace_function();
7299 ftrace_startup_sysctl();
7302 if (is_permanent_ops_registered()) {
7303 ftrace_enabled
= true;
7308 /* stopping ftrace calls (just send to ftrace_stub) */
7309 ftrace_trace_function
= ftrace_stub
;
7311 ftrace_shutdown_sysctl();
7314 last_ftrace_enabled
= !!ftrace_enabled
;
7316 mutex_unlock(&ftrace_lock
);