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_DEFAULT_BITS 10
66 #define FTRACE_HASH_MAX_BITS 12
68 #ifdef CONFIG_DYNAMIC_FTRACE
69 #define INIT_OPS_HASH(opsname) \
70 .func_hash = &opsname.local_hash, \
71 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
73 #define INIT_OPS_HASH(opsname)
77 FTRACE_MODIFY_ENABLE_FL
= (1 << 0),
78 FTRACE_MODIFY_MAY_SLEEP_FL
= (1 << 1),
81 struct ftrace_ops ftrace_list_end __read_mostly
= {
83 .flags
= FTRACE_OPS_FL_STUB
,
84 INIT_OPS_HASH(ftrace_list_end
)
87 /* ftrace_enabled is a method to turn ftrace on or off */
88 int ftrace_enabled __read_mostly
;
89 static int last_ftrace_enabled
;
91 /* Current function tracing op */
92 struct ftrace_ops
*function_trace_op __read_mostly
= &ftrace_list_end
;
93 /* What to set function_trace_op to */
94 static struct ftrace_ops
*set_function_trace_op
;
96 static bool ftrace_pids_enabled(struct ftrace_ops
*ops
)
98 struct trace_array
*tr
;
100 if (!(ops
->flags
& FTRACE_OPS_FL_PID
) || !ops
->private)
105 return tr
->function_pids
!= NULL
|| tr
->function_no_pids
!= NULL
;
108 static void ftrace_update_trampoline(struct ftrace_ops
*ops
);
111 * ftrace_disabled is set when an anomaly is discovered.
112 * ftrace_disabled is much stronger than ftrace_enabled.
114 static int ftrace_disabled __read_mostly
;
116 DEFINE_MUTEX(ftrace_lock
);
118 struct ftrace_ops __rcu
*ftrace_ops_list __read_mostly
= &ftrace_list_end
;
119 ftrace_func_t ftrace_trace_function __read_mostly
= ftrace_stub
;
120 struct ftrace_ops global_ops
;
122 #if ARCH_SUPPORTS_FTRACE_OPS
123 static void ftrace_ops_list_func(unsigned long ip
, unsigned long parent_ip
,
124 struct ftrace_ops
*op
, struct ftrace_regs
*fregs
);
126 /* See comment below, where ftrace_ops_list_func is defined */
127 static void ftrace_ops_no_ops(unsigned long ip
, unsigned long parent_ip
);
128 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
131 static inline void ftrace_ops_init(struct ftrace_ops
*ops
)
133 #ifdef CONFIG_DYNAMIC_FTRACE
134 if (!(ops
->flags
& FTRACE_OPS_FL_INITIALIZED
)) {
135 mutex_init(&ops
->local_hash
.regex_lock
);
136 ops
->func_hash
= &ops
->local_hash
;
137 ops
->flags
|= FTRACE_OPS_FL_INITIALIZED
;
142 static void ftrace_pid_func(unsigned long ip
, unsigned long parent_ip
,
143 struct ftrace_ops
*op
, struct ftrace_regs
*fregs
)
145 struct trace_array
*tr
= op
->private;
149 pid
= this_cpu_read(tr
->array_buffer
.data
->ftrace_ignore_pid
);
150 if (pid
== FTRACE_PID_IGNORE
)
152 if (pid
!= FTRACE_PID_TRACE
&&
157 op
->saved_func(ip
, parent_ip
, op
, fregs
);
160 static void ftrace_sync_ipi(void *data
)
162 /* Probably not needed, but do it anyway */
166 static ftrace_func_t
ftrace_ops_get_list_func(struct ftrace_ops
*ops
)
169 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
170 * then it needs to call the list anyway.
172 if (ops
->flags
& (FTRACE_OPS_FL_DYNAMIC
| FTRACE_OPS_FL_RCU
) ||
173 FTRACE_FORCE_LIST_FUNC
)
174 return ftrace_ops_list_func
;
176 return ftrace_ops_get_func(ops
);
179 static void update_ftrace_function(void)
184 * Prepare the ftrace_ops that the arch callback will use.
185 * If there's only one ftrace_ops registered, the ftrace_ops_list
186 * will point to the ops we want.
188 set_function_trace_op
= rcu_dereference_protected(ftrace_ops_list
,
189 lockdep_is_held(&ftrace_lock
));
191 /* If there's no ftrace_ops registered, just call the stub function */
192 if (set_function_trace_op
== &ftrace_list_end
) {
196 * If we are at the end of the list and this ops is
197 * recursion safe and not dynamic and the arch supports passing ops,
198 * then have the mcount trampoline call the function directly.
200 } else if (rcu_dereference_protected(ftrace_ops_list
->next
,
201 lockdep_is_held(&ftrace_lock
)) == &ftrace_list_end
) {
202 func
= ftrace_ops_get_list_func(ftrace_ops_list
);
205 /* Just use the default ftrace_ops */
206 set_function_trace_op
= &ftrace_list_end
;
207 func
= ftrace_ops_list_func
;
210 update_function_graph_func();
212 /* If there's no change, then do nothing more here */
213 if (ftrace_trace_function
== func
)
217 * If we are using the list function, it doesn't care
218 * about the function_trace_ops.
220 if (func
== ftrace_ops_list_func
) {
221 ftrace_trace_function
= func
;
223 * Don't even bother setting function_trace_ops,
224 * it would be racy to do so anyway.
229 #ifndef CONFIG_DYNAMIC_FTRACE
231 * For static tracing, we need to be a bit more careful.
232 * The function change takes affect immediately. Thus,
233 * we need to coordinate the setting of the function_trace_ops
234 * with the setting of the ftrace_trace_function.
236 * Set the function to the list ops, which will call the
237 * function we want, albeit indirectly, but it handles the
238 * ftrace_ops and doesn't depend on function_trace_op.
240 ftrace_trace_function
= ftrace_ops_list_func
;
242 * Make sure all CPUs see this. Yes this is slow, but static
243 * tracing is slow and nasty to have enabled.
245 synchronize_rcu_tasks_rude();
246 /* Now all cpus are using the list ops. */
247 function_trace_op
= set_function_trace_op
;
248 /* Make sure the function_trace_op is visible on all CPUs */
250 /* Nasty way to force a rmb on all cpus */
251 smp_call_function(ftrace_sync_ipi
, NULL
, 1);
252 /* OK, we are all set to update the ftrace_trace_function now! */
253 #endif /* !CONFIG_DYNAMIC_FTRACE */
255 ftrace_trace_function
= func
;
258 static void add_ftrace_ops(struct ftrace_ops __rcu
**list
,
259 struct ftrace_ops
*ops
)
261 rcu_assign_pointer(ops
->next
, *list
);
264 * We are entering ops into the list but another
265 * CPU might be walking that list. We need to make sure
266 * the ops->next pointer is valid before another CPU sees
267 * the ops pointer included into the list.
269 rcu_assign_pointer(*list
, ops
);
272 static int remove_ftrace_ops(struct ftrace_ops __rcu
**list
,
273 struct ftrace_ops
*ops
)
275 struct ftrace_ops
**p
;
278 * If we are removing the last function, then simply point
279 * to the ftrace_stub.
281 if (rcu_dereference_protected(*list
,
282 lockdep_is_held(&ftrace_lock
)) == ops
&&
283 rcu_dereference_protected(ops
->next
,
284 lockdep_is_held(&ftrace_lock
)) == &ftrace_list_end
) {
285 *list
= &ftrace_list_end
;
289 for (p
= list
; *p
!= &ftrace_list_end
; p
= &(*p
)->next
)
300 static void ftrace_update_trampoline(struct ftrace_ops
*ops
);
302 int __register_ftrace_function(struct ftrace_ops
*ops
)
304 if (ops
->flags
& FTRACE_OPS_FL_DELETED
)
307 if (WARN_ON(ops
->flags
& FTRACE_OPS_FL_ENABLED
))
310 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
312 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
313 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
314 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
316 if (ops
->flags
& FTRACE_OPS_FL_SAVE_REGS
&&
317 !(ops
->flags
& FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED
))
320 if (ops
->flags
& FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED
)
321 ops
->flags
|= FTRACE_OPS_FL_SAVE_REGS
;
323 if (!ftrace_enabled
&& (ops
->flags
& FTRACE_OPS_FL_PERMANENT
))
326 if (!core_kernel_data((unsigned long)ops
))
327 ops
->flags
|= FTRACE_OPS_FL_DYNAMIC
;
329 add_ftrace_ops(&ftrace_ops_list
, ops
);
331 /* Always save the function, and reset at unregistering */
332 ops
->saved_func
= ops
->func
;
334 if (ftrace_pids_enabled(ops
))
335 ops
->func
= ftrace_pid_func
;
337 ftrace_update_trampoline(ops
);
340 update_ftrace_function();
345 int __unregister_ftrace_function(struct ftrace_ops
*ops
)
349 if (WARN_ON(!(ops
->flags
& FTRACE_OPS_FL_ENABLED
)))
352 ret
= remove_ftrace_ops(&ftrace_ops_list
, ops
);
358 update_ftrace_function();
360 ops
->func
= ops
->saved_func
;
365 static void ftrace_update_pid_func(void)
367 struct ftrace_ops
*op
;
369 /* Only do something if we are tracing something */
370 if (ftrace_trace_function
== ftrace_stub
)
373 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
374 if (op
->flags
& FTRACE_OPS_FL_PID
) {
375 op
->func
= ftrace_pids_enabled(op
) ?
376 ftrace_pid_func
: op
->saved_func
;
377 ftrace_update_trampoline(op
);
379 } while_for_each_ftrace_op(op
);
381 update_ftrace_function();
384 #ifdef CONFIG_FUNCTION_PROFILER
385 struct ftrace_profile
{
386 struct hlist_node node
;
388 unsigned long counter
;
389 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
390 unsigned long long time
;
391 unsigned long long time_squared
;
395 struct ftrace_profile_page
{
396 struct ftrace_profile_page
*next
;
398 struct ftrace_profile records
[];
401 struct ftrace_profile_stat
{
403 struct hlist_head
*hash
;
404 struct ftrace_profile_page
*pages
;
405 struct ftrace_profile_page
*start
;
406 struct tracer_stat stat
;
409 #define PROFILE_RECORDS_SIZE \
410 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
412 #define PROFILES_PER_PAGE \
413 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
415 static int ftrace_profile_enabled __read_mostly
;
417 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
418 static DEFINE_MUTEX(ftrace_profile_lock
);
420 static DEFINE_PER_CPU(struct ftrace_profile_stat
, ftrace_profile_stats
);
422 #define FTRACE_PROFILE_HASH_BITS 10
423 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
426 function_stat_next(void *v
, int idx
)
428 struct ftrace_profile
*rec
= v
;
429 struct ftrace_profile_page
*pg
;
431 pg
= (struct ftrace_profile_page
*)((unsigned long)rec
& PAGE_MASK
);
437 if ((void *)rec
>= (void *)&pg
->records
[pg
->index
]) {
441 rec
= &pg
->records
[0];
449 static void *function_stat_start(struct tracer_stat
*trace
)
451 struct ftrace_profile_stat
*stat
=
452 container_of(trace
, struct ftrace_profile_stat
, stat
);
454 if (!stat
|| !stat
->start
)
457 return function_stat_next(&stat
->start
->records
[0], 0);
460 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
461 /* function graph compares on total time */
462 static int function_stat_cmp(const void *p1
, const void *p2
)
464 const struct ftrace_profile
*a
= p1
;
465 const struct ftrace_profile
*b
= p2
;
467 if (a
->time
< b
->time
)
469 if (a
->time
> b
->time
)
475 /* not function graph compares against hits */
476 static int function_stat_cmp(const void *p1
, const void *p2
)
478 const struct ftrace_profile
*a
= p1
;
479 const struct ftrace_profile
*b
= p2
;
481 if (a
->counter
< b
->counter
)
483 if (a
->counter
> b
->counter
)
490 static int function_stat_headers(struct seq_file
*m
)
492 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
493 seq_puts(m
, " Function "
496 "--- ---- --- ---\n");
498 seq_puts(m
, " Function Hit\n"
504 static int function_stat_show(struct seq_file
*m
, void *v
)
506 struct ftrace_profile
*rec
= v
;
507 char str
[KSYM_SYMBOL_LEN
];
509 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
510 static struct trace_seq s
;
511 unsigned long long avg
;
512 unsigned long long stddev
;
514 mutex_lock(&ftrace_profile_lock
);
516 /* we raced with function_profile_reset() */
517 if (unlikely(rec
->counter
== 0)) {
522 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
523 avg
= div64_ul(rec
->time
, rec
->counter
);
524 if (tracing_thresh
&& (avg
< tracing_thresh
))
528 kallsyms_lookup(rec
->ip
, NULL
, NULL
, NULL
, str
);
529 seq_printf(m
, " %-30.30s %10lu", str
, rec
->counter
);
531 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
534 /* Sample standard deviation (s^2) */
535 if (rec
->counter
<= 1)
539 * Apply Welford's method:
540 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
542 stddev
= rec
->counter
* rec
->time_squared
-
543 rec
->time
* rec
->time
;
546 * Divide only 1000 for ns^2 -> us^2 conversion.
547 * trace_print_graph_duration will divide 1000 again.
549 stddev
= div64_ul(stddev
,
550 rec
->counter
* (rec
->counter
- 1) * 1000);
554 trace_print_graph_duration(rec
->time
, &s
);
555 trace_seq_puts(&s
, " ");
556 trace_print_graph_duration(avg
, &s
);
557 trace_seq_puts(&s
, " ");
558 trace_print_graph_duration(stddev
, &s
);
559 trace_print_seq(m
, &s
);
563 mutex_unlock(&ftrace_profile_lock
);
568 static void ftrace_profile_reset(struct ftrace_profile_stat
*stat
)
570 struct ftrace_profile_page
*pg
;
572 pg
= stat
->pages
= stat
->start
;
575 memset(pg
->records
, 0, PROFILE_RECORDS_SIZE
);
580 memset(stat
->hash
, 0,
581 FTRACE_PROFILE_HASH_SIZE
* sizeof(struct hlist_head
));
584 int ftrace_profile_pages_init(struct ftrace_profile_stat
*stat
)
586 struct ftrace_profile_page
*pg
;
591 /* If we already allocated, do nothing */
595 stat
->pages
= (void *)get_zeroed_page(GFP_KERNEL
);
599 #ifdef CONFIG_DYNAMIC_FTRACE
600 functions
= ftrace_update_tot_cnt
;
603 * We do not know the number of functions that exist because
604 * dynamic tracing is what counts them. With past experience
605 * we have around 20K functions. That should be more than enough.
606 * It is highly unlikely we will execute every function in
612 pg
= stat
->start
= stat
->pages
;
614 pages
= DIV_ROUND_UP(functions
, PROFILES_PER_PAGE
);
616 for (i
= 1; i
< pages
; i
++) {
617 pg
->next
= (void *)get_zeroed_page(GFP_KERNEL
);
628 unsigned long tmp
= (unsigned long)pg
;
640 static int ftrace_profile_init_cpu(int cpu
)
642 struct ftrace_profile_stat
*stat
;
645 stat
= &per_cpu(ftrace_profile_stats
, cpu
);
648 /* If the profile is already created, simply reset it */
649 ftrace_profile_reset(stat
);
654 * We are profiling all functions, but usually only a few thousand
655 * functions are hit. We'll make a hash of 1024 items.
657 size
= FTRACE_PROFILE_HASH_SIZE
;
659 stat
->hash
= kcalloc(size
, sizeof(struct hlist_head
), GFP_KERNEL
);
664 /* Preallocate the function profiling pages */
665 if (ftrace_profile_pages_init(stat
) < 0) {
674 static int ftrace_profile_init(void)
679 for_each_possible_cpu(cpu
) {
680 ret
= ftrace_profile_init_cpu(cpu
);
688 /* interrupts must be disabled */
689 static struct ftrace_profile
*
690 ftrace_find_profiled_func(struct ftrace_profile_stat
*stat
, unsigned long ip
)
692 struct ftrace_profile
*rec
;
693 struct hlist_head
*hhd
;
696 key
= hash_long(ip
, FTRACE_PROFILE_HASH_BITS
);
697 hhd
= &stat
->hash
[key
];
699 if (hlist_empty(hhd
))
702 hlist_for_each_entry_rcu_notrace(rec
, hhd
, node
) {
710 static void ftrace_add_profile(struct ftrace_profile_stat
*stat
,
711 struct ftrace_profile
*rec
)
715 key
= hash_long(rec
->ip
, FTRACE_PROFILE_HASH_BITS
);
716 hlist_add_head_rcu(&rec
->node
, &stat
->hash
[key
]);
720 * The memory is already allocated, this simply finds a new record to use.
722 static struct ftrace_profile
*
723 ftrace_profile_alloc(struct ftrace_profile_stat
*stat
, unsigned long ip
)
725 struct ftrace_profile
*rec
= NULL
;
727 /* prevent recursion (from NMIs) */
728 if (atomic_inc_return(&stat
->disabled
) != 1)
732 * Try to find the function again since an NMI
733 * could have added it
735 rec
= ftrace_find_profiled_func(stat
, ip
);
739 if (stat
->pages
->index
== PROFILES_PER_PAGE
) {
740 if (!stat
->pages
->next
)
742 stat
->pages
= stat
->pages
->next
;
745 rec
= &stat
->pages
->records
[stat
->pages
->index
++];
747 ftrace_add_profile(stat
, rec
);
750 atomic_dec(&stat
->disabled
);
756 function_profile_call(unsigned long ip
, unsigned long parent_ip
,
757 struct ftrace_ops
*ops
, struct ftrace_regs
*fregs
)
759 struct ftrace_profile_stat
*stat
;
760 struct ftrace_profile
*rec
;
763 if (!ftrace_profile_enabled
)
766 local_irq_save(flags
);
768 stat
= this_cpu_ptr(&ftrace_profile_stats
);
769 if (!stat
->hash
|| !ftrace_profile_enabled
)
772 rec
= ftrace_find_profiled_func(stat
, ip
);
774 rec
= ftrace_profile_alloc(stat
, ip
);
781 local_irq_restore(flags
);
784 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
785 static bool fgraph_graph_time
= true;
787 void ftrace_graph_graph_time_control(bool enable
)
789 fgraph_graph_time
= enable
;
792 static int profile_graph_entry(struct ftrace_graph_ent
*trace
)
794 struct ftrace_ret_stack
*ret_stack
;
796 function_profile_call(trace
->func
, 0, NULL
, NULL
);
798 /* If function graph is shutting down, ret_stack can be NULL */
799 if (!current
->ret_stack
)
802 ret_stack
= ftrace_graph_get_ret_stack(current
, 0);
804 ret_stack
->subtime
= 0;
809 static void profile_graph_return(struct ftrace_graph_ret
*trace
)
811 struct ftrace_ret_stack
*ret_stack
;
812 struct ftrace_profile_stat
*stat
;
813 unsigned long long calltime
;
814 struct ftrace_profile
*rec
;
817 local_irq_save(flags
);
818 stat
= this_cpu_ptr(&ftrace_profile_stats
);
819 if (!stat
->hash
|| !ftrace_profile_enabled
)
822 /* If the calltime was zero'd ignore it */
823 if (!trace
->calltime
)
826 calltime
= trace
->rettime
- trace
->calltime
;
828 if (!fgraph_graph_time
) {
830 /* Append this call time to the parent time to subtract */
831 ret_stack
= ftrace_graph_get_ret_stack(current
, 1);
833 ret_stack
->subtime
+= calltime
;
835 ret_stack
= ftrace_graph_get_ret_stack(current
, 0);
836 if (ret_stack
&& ret_stack
->subtime
< calltime
)
837 calltime
-= ret_stack
->subtime
;
842 rec
= ftrace_find_profiled_func(stat
, trace
->func
);
844 rec
->time
+= calltime
;
845 rec
->time_squared
+= calltime
* calltime
;
849 local_irq_restore(flags
);
852 static struct fgraph_ops fprofiler_ops
= {
853 .entryfunc
= &profile_graph_entry
,
854 .retfunc
= &profile_graph_return
,
857 static int register_ftrace_profiler(void)
859 return register_ftrace_graph(&fprofiler_ops
);
862 static void unregister_ftrace_profiler(void)
864 unregister_ftrace_graph(&fprofiler_ops
);
867 static struct ftrace_ops ftrace_profile_ops __read_mostly
= {
868 .func
= function_profile_call
,
869 .flags
= FTRACE_OPS_FL_INITIALIZED
,
870 INIT_OPS_HASH(ftrace_profile_ops
)
873 static int register_ftrace_profiler(void)
875 return register_ftrace_function(&ftrace_profile_ops
);
878 static void unregister_ftrace_profiler(void)
880 unregister_ftrace_function(&ftrace_profile_ops
);
882 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
885 ftrace_profile_write(struct file
*filp
, const char __user
*ubuf
,
886 size_t cnt
, loff_t
*ppos
)
891 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
897 mutex_lock(&ftrace_profile_lock
);
898 if (ftrace_profile_enabled
^ val
) {
900 ret
= ftrace_profile_init();
906 ret
= register_ftrace_profiler();
911 ftrace_profile_enabled
= 1;
913 ftrace_profile_enabled
= 0;
915 * unregister_ftrace_profiler calls stop_machine
916 * so this acts like an synchronize_rcu.
918 unregister_ftrace_profiler();
922 mutex_unlock(&ftrace_profile_lock
);
930 ftrace_profile_read(struct file
*filp
, char __user
*ubuf
,
931 size_t cnt
, loff_t
*ppos
)
933 char buf
[64]; /* big enough to hold a number */
936 r
= sprintf(buf
, "%u\n", ftrace_profile_enabled
);
937 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
940 static const struct file_operations ftrace_profile_fops
= {
941 .open
= tracing_open_generic
,
942 .read
= ftrace_profile_read
,
943 .write
= ftrace_profile_write
,
944 .llseek
= default_llseek
,
947 /* used to initialize the real stat files */
948 static struct tracer_stat function_stats __initdata
= {
950 .stat_start
= function_stat_start
,
951 .stat_next
= function_stat_next
,
952 .stat_cmp
= function_stat_cmp
,
953 .stat_headers
= function_stat_headers
,
954 .stat_show
= function_stat_show
957 static __init
void ftrace_profile_tracefs(struct dentry
*d_tracer
)
959 struct ftrace_profile_stat
*stat
;
960 struct dentry
*entry
;
965 for_each_possible_cpu(cpu
) {
966 stat
= &per_cpu(ftrace_profile_stats
, cpu
);
968 name
= kasprintf(GFP_KERNEL
, "function%d", cpu
);
971 * The files created are permanent, if something happens
972 * we still do not free memory.
975 "Could not allocate stat file for cpu %d\n",
979 stat
->stat
= function_stats
;
980 stat
->stat
.name
= name
;
981 ret
= register_stat_tracer(&stat
->stat
);
984 "Could not register function stat for cpu %d\n",
991 entry
= tracefs_create_file("function_profile_enabled",
992 TRACE_MODE_WRITE
, d_tracer
, NULL
,
993 &ftrace_profile_fops
);
995 pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
998 #else /* CONFIG_FUNCTION_PROFILER */
999 static __init
void ftrace_profile_tracefs(struct dentry
*d_tracer
)
1002 #endif /* CONFIG_FUNCTION_PROFILER */
1004 #ifdef CONFIG_DYNAMIC_FTRACE
1006 static struct ftrace_ops
*removed_ops
;
1009 * Set when doing a global update, like enabling all recs or disabling them.
1010 * It is not set when just updating a single ftrace_ops.
1012 static bool update_all_ops
;
1014 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1015 # error Dynamic ftrace depends on MCOUNT_RECORD
1018 struct ftrace_func_probe
{
1019 struct ftrace_probe_ops
*probe_ops
;
1020 struct ftrace_ops ops
;
1021 struct trace_array
*tr
;
1022 struct list_head list
;
1028 * We make these constant because no one should touch them,
1029 * but they are used as the default "empty hash", to avoid allocating
1030 * it all the time. These are in a read only section such that if
1031 * anyone does try to modify it, it will cause an exception.
1033 static const struct hlist_head empty_buckets
[1];
1034 static const struct ftrace_hash empty_hash
= {
1035 .buckets
= (struct hlist_head
*)empty_buckets
,
1037 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1039 struct ftrace_ops global_ops
= {
1040 .func
= ftrace_stub
,
1041 .local_hash
.notrace_hash
= EMPTY_HASH
,
1042 .local_hash
.filter_hash
= EMPTY_HASH
,
1043 INIT_OPS_HASH(global_ops
)
1044 .flags
= FTRACE_OPS_FL_INITIALIZED
|
1049 * Used by the stack unwinder to know about dynamic ftrace trampolines.
1051 struct ftrace_ops
*ftrace_ops_trampoline(unsigned long addr
)
1053 struct ftrace_ops
*op
= NULL
;
1056 * Some of the ops may be dynamically allocated,
1057 * they are freed after a synchronize_rcu().
1059 preempt_disable_notrace();
1061 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
1063 * This is to check for dynamically allocated trampolines.
1064 * Trampolines that are in kernel text will have
1065 * core_kernel_text() return true.
1067 if (op
->trampoline
&& op
->trampoline_size
)
1068 if (addr
>= op
->trampoline
&&
1069 addr
< op
->trampoline
+ op
->trampoline_size
) {
1070 preempt_enable_notrace();
1073 } while_for_each_ftrace_op(op
);
1074 preempt_enable_notrace();
1080 * This is used by __kernel_text_address() to return true if the
1081 * address is on a dynamically allocated trampoline that would
1082 * not return true for either core_kernel_text() or
1083 * is_module_text_address().
1085 bool is_ftrace_trampoline(unsigned long addr
)
1087 return ftrace_ops_trampoline(addr
) != NULL
;
1090 struct ftrace_page
{
1091 struct ftrace_page
*next
;
1092 struct dyn_ftrace
*records
;
1097 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1098 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1100 static struct ftrace_page
*ftrace_pages_start
;
1101 static struct ftrace_page
*ftrace_pages
;
1103 static __always_inline
unsigned long
1104 ftrace_hash_key(struct ftrace_hash
*hash
, unsigned long ip
)
1106 if (hash
->size_bits
> 0)
1107 return hash_long(ip
, hash
->size_bits
);
1112 /* Only use this function if ftrace_hash_empty() has already been tested */
1113 static __always_inline
struct ftrace_func_entry
*
1114 __ftrace_lookup_ip(struct ftrace_hash
*hash
, unsigned long ip
)
1117 struct ftrace_func_entry
*entry
;
1118 struct hlist_head
*hhd
;
1120 key
= ftrace_hash_key(hash
, ip
);
1121 hhd
= &hash
->buckets
[key
];
1123 hlist_for_each_entry_rcu_notrace(entry
, hhd
, hlist
) {
1124 if (entry
->ip
== ip
)
1131 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1132 * @hash: The hash to look at
1133 * @ip: The instruction pointer to test
1135 * Search a given @hash to see if a given instruction pointer (@ip)
1138 * Returns the entry that holds the @ip if found. NULL otherwise.
1140 struct ftrace_func_entry
*
1141 ftrace_lookup_ip(struct ftrace_hash
*hash
, unsigned long ip
)
1143 if (ftrace_hash_empty(hash
))
1146 return __ftrace_lookup_ip(hash
, ip
);
1149 static void __add_hash_entry(struct ftrace_hash
*hash
,
1150 struct ftrace_func_entry
*entry
)
1152 struct hlist_head
*hhd
;
1155 key
= ftrace_hash_key(hash
, entry
->ip
);
1156 hhd
= &hash
->buckets
[key
];
1157 hlist_add_head(&entry
->hlist
, hhd
);
1161 static int add_hash_entry(struct ftrace_hash
*hash
, unsigned long ip
)
1163 struct ftrace_func_entry
*entry
;
1165 entry
= kmalloc(sizeof(*entry
), GFP_KERNEL
);
1170 __add_hash_entry(hash
, entry
);
1176 free_hash_entry(struct ftrace_hash
*hash
,
1177 struct ftrace_func_entry
*entry
)
1179 hlist_del(&entry
->hlist
);
1185 remove_hash_entry(struct ftrace_hash
*hash
,
1186 struct ftrace_func_entry
*entry
)
1188 hlist_del_rcu(&entry
->hlist
);
1192 static void ftrace_hash_clear(struct ftrace_hash
*hash
)
1194 struct hlist_head
*hhd
;
1195 struct hlist_node
*tn
;
1196 struct ftrace_func_entry
*entry
;
1197 int size
= 1 << hash
->size_bits
;
1203 for (i
= 0; i
< size
; i
++) {
1204 hhd
= &hash
->buckets
[i
];
1205 hlist_for_each_entry_safe(entry
, tn
, hhd
, hlist
)
1206 free_hash_entry(hash
, entry
);
1208 FTRACE_WARN_ON(hash
->count
);
1211 static void free_ftrace_mod(struct ftrace_mod_load
*ftrace_mod
)
1213 list_del(&ftrace_mod
->list
);
1214 kfree(ftrace_mod
->module
);
1215 kfree(ftrace_mod
->func
);
1219 static void clear_ftrace_mod_list(struct list_head
*head
)
1221 struct ftrace_mod_load
*p
, *n
;
1223 /* stack tracer isn't supported yet */
1227 mutex_lock(&ftrace_lock
);
1228 list_for_each_entry_safe(p
, n
, head
, list
)
1230 mutex_unlock(&ftrace_lock
);
1233 static void free_ftrace_hash(struct ftrace_hash
*hash
)
1235 if (!hash
|| hash
== EMPTY_HASH
)
1237 ftrace_hash_clear(hash
);
1238 kfree(hash
->buckets
);
1242 static void __free_ftrace_hash_rcu(struct rcu_head
*rcu
)
1244 struct ftrace_hash
*hash
;
1246 hash
= container_of(rcu
, struct ftrace_hash
, rcu
);
1247 free_ftrace_hash(hash
);
1250 static void free_ftrace_hash_rcu(struct ftrace_hash
*hash
)
1252 if (!hash
|| hash
== EMPTY_HASH
)
1254 call_rcu(&hash
->rcu
, __free_ftrace_hash_rcu
);
1257 void ftrace_free_filter(struct ftrace_ops
*ops
)
1259 ftrace_ops_init(ops
);
1260 free_ftrace_hash(ops
->func_hash
->filter_hash
);
1261 free_ftrace_hash(ops
->func_hash
->notrace_hash
);
1264 static struct ftrace_hash
*alloc_ftrace_hash(int size_bits
)
1266 struct ftrace_hash
*hash
;
1269 hash
= kzalloc(sizeof(*hash
), GFP_KERNEL
);
1273 size
= 1 << size_bits
;
1274 hash
->buckets
= kcalloc(size
, sizeof(*hash
->buckets
), GFP_KERNEL
);
1276 if (!hash
->buckets
) {
1281 hash
->size_bits
= size_bits
;
1287 static int ftrace_add_mod(struct trace_array
*tr
,
1288 const char *func
, const char *module
,
1291 struct ftrace_mod_load
*ftrace_mod
;
1292 struct list_head
*mod_head
= enable
? &tr
->mod_trace
: &tr
->mod_notrace
;
1294 ftrace_mod
= kzalloc(sizeof(*ftrace_mod
), GFP_KERNEL
);
1298 ftrace_mod
->func
= kstrdup(func
, GFP_KERNEL
);
1299 ftrace_mod
->module
= kstrdup(module
, GFP_KERNEL
);
1300 ftrace_mod
->enable
= enable
;
1302 if (!ftrace_mod
->func
|| !ftrace_mod
->module
)
1305 list_add(&ftrace_mod
->list
, mod_head
);
1310 free_ftrace_mod(ftrace_mod
);
1315 static struct ftrace_hash
*
1316 alloc_and_copy_ftrace_hash(int size_bits
, struct ftrace_hash
*hash
)
1318 struct ftrace_func_entry
*entry
;
1319 struct ftrace_hash
*new_hash
;
1324 new_hash
= alloc_ftrace_hash(size_bits
);
1329 new_hash
->flags
= hash
->flags
;
1332 if (ftrace_hash_empty(hash
))
1335 size
= 1 << hash
->size_bits
;
1336 for (i
= 0; i
< size
; i
++) {
1337 hlist_for_each_entry(entry
, &hash
->buckets
[i
], hlist
) {
1338 ret
= add_hash_entry(new_hash
, entry
->ip
);
1344 FTRACE_WARN_ON(new_hash
->count
!= hash
->count
);
1349 free_ftrace_hash(new_hash
);
1354 ftrace_hash_rec_disable_modify(struct ftrace_ops
*ops
, int filter_hash
);
1356 ftrace_hash_rec_enable_modify(struct ftrace_ops
*ops
, int filter_hash
);
1358 static int ftrace_hash_ipmodify_update(struct ftrace_ops
*ops
,
1359 struct ftrace_hash
*new_hash
);
1361 static struct ftrace_hash
*dup_hash(struct ftrace_hash
*src
, int size
)
1363 struct ftrace_func_entry
*entry
;
1364 struct ftrace_hash
*new_hash
;
1365 struct hlist_head
*hhd
;
1366 struct hlist_node
*tn
;
1371 * Use around half the size (max bit of it), but
1372 * a minimum of 2 is fine (as size of 0 or 1 both give 1 for bits).
1374 bits
= fls(size
/ 2);
1376 /* Don't allocate too much */
1377 if (bits
> FTRACE_HASH_MAX_BITS
)
1378 bits
= FTRACE_HASH_MAX_BITS
;
1380 new_hash
= alloc_ftrace_hash(bits
);
1384 new_hash
->flags
= src
->flags
;
1386 size
= 1 << src
->size_bits
;
1387 for (i
= 0; i
< size
; i
++) {
1388 hhd
= &src
->buckets
[i
];
1389 hlist_for_each_entry_safe(entry
, tn
, hhd
, hlist
) {
1390 remove_hash_entry(src
, entry
);
1391 __add_hash_entry(new_hash
, entry
);
1397 static struct ftrace_hash
*
1398 __ftrace_hash_move(struct ftrace_hash
*src
)
1400 int size
= src
->count
;
1403 * If the new source is empty, just return the empty_hash.
1405 if (ftrace_hash_empty(src
))
1408 return dup_hash(src
, size
);
1412 ftrace_hash_move(struct ftrace_ops
*ops
, int enable
,
1413 struct ftrace_hash
**dst
, struct ftrace_hash
*src
)
1415 struct ftrace_hash
*new_hash
;
1418 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1419 if (ops
->flags
& FTRACE_OPS_FL_IPMODIFY
&& !enable
)
1422 new_hash
= __ftrace_hash_move(src
);
1426 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1428 /* IPMODIFY should be updated only when filter_hash updating */
1429 ret
= ftrace_hash_ipmodify_update(ops
, new_hash
);
1431 free_ftrace_hash(new_hash
);
1437 * Remove the current set, update the hash and add
1440 ftrace_hash_rec_disable_modify(ops
, enable
);
1442 rcu_assign_pointer(*dst
, new_hash
);
1444 ftrace_hash_rec_enable_modify(ops
, enable
);
1449 static bool hash_contains_ip(unsigned long ip
,
1450 struct ftrace_ops_hash
*hash
)
1453 * The function record is a match if it exists in the filter
1454 * hash and not in the notrace hash. Note, an empty hash is
1455 * considered a match for the filter hash, but an empty
1456 * notrace hash is considered not in the notrace hash.
1458 return (ftrace_hash_empty(hash
->filter_hash
) ||
1459 __ftrace_lookup_ip(hash
->filter_hash
, ip
)) &&
1460 (ftrace_hash_empty(hash
->notrace_hash
) ||
1461 !__ftrace_lookup_ip(hash
->notrace_hash
, ip
));
1465 * Test the hashes for this ops to see if we want to call
1466 * the ops->func or not.
1468 * It's a match if the ip is in the ops->filter_hash or
1469 * the filter_hash does not exist or is empty,
1471 * the ip is not in the ops->notrace_hash.
1473 * This needs to be called with preemption disabled as
1474 * the hashes are freed with call_rcu().
1477 ftrace_ops_test(struct ftrace_ops
*ops
, unsigned long ip
, void *regs
)
1479 struct ftrace_ops_hash hash
;
1482 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1484 * There's a small race when adding ops that the ftrace handler
1485 * that wants regs, may be called without them. We can not
1486 * allow that handler to be called if regs is NULL.
1488 if (regs
== NULL
&& (ops
->flags
& FTRACE_OPS_FL_SAVE_REGS
))
1492 rcu_assign_pointer(hash
.filter_hash
, ops
->func_hash
->filter_hash
);
1493 rcu_assign_pointer(hash
.notrace_hash
, ops
->func_hash
->notrace_hash
);
1495 if (hash_contains_ip(ip
, &hash
))
1504 * This is a double for. Do not use 'break' to break out of the loop,
1505 * you must use a goto.
1507 #define do_for_each_ftrace_rec(pg, rec) \
1508 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1510 for (_____i = 0; _____i < pg->index; _____i++) { \
1511 rec = &pg->records[_____i];
1513 #define while_for_each_ftrace_rec() \
1518 static int ftrace_cmp_recs(const void *a
, const void *b
)
1520 const struct dyn_ftrace
*key
= a
;
1521 const struct dyn_ftrace
*rec
= b
;
1523 if (key
->flags
< rec
->ip
)
1525 if (key
->ip
>= rec
->ip
+ MCOUNT_INSN_SIZE
)
1530 static struct dyn_ftrace
*lookup_rec(unsigned long start
, unsigned long end
)
1532 struct ftrace_page
*pg
;
1533 struct dyn_ftrace
*rec
= NULL
;
1534 struct dyn_ftrace key
;
1537 key
.flags
= end
; /* overload flags, as it is unsigned long */
1539 for (pg
= ftrace_pages_start
; pg
; pg
= pg
->next
) {
1540 if (end
< pg
->records
[0].ip
||
1541 start
>= (pg
->records
[pg
->index
- 1].ip
+ MCOUNT_INSN_SIZE
))
1543 rec
= bsearch(&key
, pg
->records
, pg
->index
,
1544 sizeof(struct dyn_ftrace
),
1553 * ftrace_location_range - return the first address of a traced location
1554 * if it touches the given ip range
1555 * @start: start of range to search.
1556 * @end: end of range to search (inclusive). @end points to the last byte
1559 * Returns rec->ip if the related ftrace location is a least partly within
1560 * the given address range. That is, the first address of the instruction
1561 * that is either a NOP or call to the function tracer. It checks the ftrace
1562 * internal tables to determine if the address belongs or not.
1564 unsigned long ftrace_location_range(unsigned long start
, unsigned long end
)
1566 struct dyn_ftrace
*rec
;
1568 rec
= lookup_rec(start
, end
);
1576 * ftrace_location - return true if the ip giving is a traced location
1577 * @ip: the instruction pointer to check
1579 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1580 * That is, the instruction that is either a NOP or call to
1581 * the function tracer. It checks the ftrace internal tables to
1582 * determine if the address belongs or not.
1584 unsigned long ftrace_location(unsigned long ip
)
1586 return ftrace_location_range(ip
, ip
);
1590 * ftrace_text_reserved - return true if range contains an ftrace location
1591 * @start: start of range to search
1592 * @end: end of range to search (inclusive). @end points to the last byte to check.
1594 * Returns 1 if @start and @end contains a ftrace location.
1595 * That is, the instruction that is either a NOP or call to
1596 * the function tracer. It checks the ftrace internal tables to
1597 * determine if the address belongs or not.
1599 int ftrace_text_reserved(const void *start
, const void *end
)
1603 ret
= ftrace_location_range((unsigned long)start
,
1604 (unsigned long)end
);
1609 /* Test if ops registered to this rec needs regs */
1610 static bool test_rec_ops_needs_regs(struct dyn_ftrace
*rec
)
1612 struct ftrace_ops
*ops
;
1613 bool keep_regs
= false;
1615 for (ops
= ftrace_ops_list
;
1616 ops
!= &ftrace_list_end
; ops
= ops
->next
) {
1617 /* pass rec in as regs to have non-NULL val */
1618 if (ftrace_ops_test(ops
, rec
->ip
, rec
)) {
1619 if (ops
->flags
& FTRACE_OPS_FL_SAVE_REGS
) {
1629 static struct ftrace_ops
*
1630 ftrace_find_tramp_ops_any(struct dyn_ftrace
*rec
);
1631 static struct ftrace_ops
*
1632 ftrace_find_tramp_ops_any_other(struct dyn_ftrace
*rec
, struct ftrace_ops
*op_exclude
);
1633 static struct ftrace_ops
*
1634 ftrace_find_tramp_ops_next(struct dyn_ftrace
*rec
, struct ftrace_ops
*ops
);
1636 static bool __ftrace_hash_rec_update(struct ftrace_ops
*ops
,
1640 struct ftrace_hash
*hash
;
1641 struct ftrace_hash
*other_hash
;
1642 struct ftrace_page
*pg
;
1643 struct dyn_ftrace
*rec
;
1644 bool update
= false;
1648 /* Only update if the ops has been registered */
1649 if (!(ops
->flags
& FTRACE_OPS_FL_ENABLED
))
1653 * In the filter_hash case:
1654 * If the count is zero, we update all records.
1655 * Otherwise we just update the items in the hash.
1657 * In the notrace_hash case:
1658 * We enable the update in the hash.
1659 * As disabling notrace means enabling the tracing,
1660 * and enabling notrace means disabling, the inc variable
1664 hash
= ops
->func_hash
->filter_hash
;
1665 other_hash
= ops
->func_hash
->notrace_hash
;
1666 if (ftrace_hash_empty(hash
))
1670 hash
= ops
->func_hash
->notrace_hash
;
1671 other_hash
= ops
->func_hash
->filter_hash
;
1673 * If the notrace hash has no items,
1674 * then there's nothing to do.
1676 if (ftrace_hash_empty(hash
))
1680 do_for_each_ftrace_rec(pg
, rec
) {
1681 int in_other_hash
= 0;
1685 if (rec
->flags
& FTRACE_FL_DISABLED
)
1690 * Only the filter_hash affects all records.
1691 * Update if the record is not in the notrace hash.
1693 if (!other_hash
|| !ftrace_lookup_ip(other_hash
, rec
->ip
))
1696 in_hash
= !!ftrace_lookup_ip(hash
, rec
->ip
);
1697 in_other_hash
= !!ftrace_lookup_ip(other_hash
, rec
->ip
);
1700 * If filter_hash is set, we want to match all functions
1701 * that are in the hash but not in the other hash.
1703 * If filter_hash is not set, then we are decrementing.
1704 * That means we match anything that is in the hash
1705 * and also in the other_hash. That is, we need to turn
1706 * off functions in the other hash because they are disabled
1709 if (filter_hash
&& in_hash
&& !in_other_hash
)
1711 else if (!filter_hash
&& in_hash
&&
1712 (in_other_hash
|| ftrace_hash_empty(other_hash
)))
1720 if (FTRACE_WARN_ON(ftrace_rec_count(rec
) == FTRACE_REF_MAX
))
1723 if (ops
->flags
& FTRACE_OPS_FL_DIRECT
)
1724 rec
->flags
|= FTRACE_FL_DIRECT
;
1727 * If there's only a single callback registered to a
1728 * function, and the ops has a trampoline registered
1729 * for it, then we can call it directly.
1731 if (ftrace_rec_count(rec
) == 1 && ops
->trampoline
)
1732 rec
->flags
|= FTRACE_FL_TRAMP
;
1735 * If we are adding another function callback
1736 * to this function, and the previous had a
1737 * custom trampoline in use, then we need to go
1738 * back to the default trampoline.
1740 rec
->flags
&= ~FTRACE_FL_TRAMP
;
1743 * If any ops wants regs saved for this function
1744 * then all ops will get saved regs.
1746 if (ops
->flags
& FTRACE_OPS_FL_SAVE_REGS
)
1747 rec
->flags
|= FTRACE_FL_REGS
;
1749 if (FTRACE_WARN_ON(ftrace_rec_count(rec
) == 0))
1754 * Only the internal direct_ops should have the
1755 * DIRECT flag set. Thus, if it is removing a
1756 * function, then that function should no longer
1759 if (ops
->flags
& FTRACE_OPS_FL_DIRECT
)
1760 rec
->flags
&= ~FTRACE_FL_DIRECT
;
1763 * If the rec had REGS enabled and the ops that is
1764 * being removed had REGS set, then see if there is
1765 * still any ops for this record that wants regs.
1766 * If not, we can stop recording them.
1768 if (ftrace_rec_count(rec
) > 0 &&
1769 rec
->flags
& FTRACE_FL_REGS
&&
1770 ops
->flags
& FTRACE_OPS_FL_SAVE_REGS
) {
1771 if (!test_rec_ops_needs_regs(rec
))
1772 rec
->flags
&= ~FTRACE_FL_REGS
;
1776 * The TRAMP needs to be set only if rec count
1777 * is decremented to one, and the ops that is
1778 * left has a trampoline. As TRAMP can only be
1779 * enabled if there is only a single ops attached
1782 if (ftrace_rec_count(rec
) == 1 &&
1783 ftrace_find_tramp_ops_any_other(rec
, ops
))
1784 rec
->flags
|= FTRACE_FL_TRAMP
;
1786 rec
->flags
&= ~FTRACE_FL_TRAMP
;
1789 * flags will be cleared in ftrace_check_record()
1790 * if rec count is zero.
1795 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1796 update
|= ftrace_test_record(rec
, true) != FTRACE_UPDATE_IGNORE
;
1798 /* Shortcut, if we handled all records, we are done. */
1799 if (!all
&& count
== hash
->count
)
1801 } while_for_each_ftrace_rec();
1806 static bool ftrace_hash_rec_disable(struct ftrace_ops
*ops
,
1809 return __ftrace_hash_rec_update(ops
, filter_hash
, 0);
1812 static bool ftrace_hash_rec_enable(struct ftrace_ops
*ops
,
1815 return __ftrace_hash_rec_update(ops
, filter_hash
, 1);
1818 static void ftrace_hash_rec_update_modify(struct ftrace_ops
*ops
,
1819 int filter_hash
, int inc
)
1821 struct ftrace_ops
*op
;
1823 __ftrace_hash_rec_update(ops
, filter_hash
, inc
);
1825 if (ops
->func_hash
!= &global_ops
.local_hash
)
1829 * If the ops shares the global_ops hash, then we need to update
1830 * all ops that are enabled and use this hash.
1832 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
1836 if (op
->func_hash
== &global_ops
.local_hash
)
1837 __ftrace_hash_rec_update(op
, filter_hash
, inc
);
1838 } while_for_each_ftrace_op(op
);
1841 static void ftrace_hash_rec_disable_modify(struct ftrace_ops
*ops
,
1844 ftrace_hash_rec_update_modify(ops
, filter_hash
, 0);
1847 static void ftrace_hash_rec_enable_modify(struct ftrace_ops
*ops
,
1850 ftrace_hash_rec_update_modify(ops
, filter_hash
, 1);
1854 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1855 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1856 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1857 * Note that old_hash and new_hash has below meanings
1858 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1859 * - If the hash is EMPTY_HASH, it hits nothing
1860 * - Anything else hits the recs which match the hash entries.
1862 static int __ftrace_hash_update_ipmodify(struct ftrace_ops
*ops
,
1863 struct ftrace_hash
*old_hash
,
1864 struct ftrace_hash
*new_hash
)
1866 struct ftrace_page
*pg
;
1867 struct dyn_ftrace
*rec
, *end
= NULL
;
1870 /* Only update if the ops has been registered */
1871 if (!(ops
->flags
& FTRACE_OPS_FL_ENABLED
))
1874 if (!(ops
->flags
& FTRACE_OPS_FL_IPMODIFY
))
1878 * Since the IPMODIFY is a very address sensitive action, we do not
1879 * allow ftrace_ops to set all functions to new hash.
1881 if (!new_hash
|| !old_hash
)
1884 /* Update rec->flags */
1885 do_for_each_ftrace_rec(pg
, rec
) {
1887 if (rec
->flags
& FTRACE_FL_DISABLED
)
1890 /* We need to update only differences of filter_hash */
1891 in_old
= !!ftrace_lookup_ip(old_hash
, rec
->ip
);
1892 in_new
= !!ftrace_lookup_ip(new_hash
, rec
->ip
);
1893 if (in_old
== in_new
)
1897 /* New entries must ensure no others are using it */
1898 if (rec
->flags
& FTRACE_FL_IPMODIFY
)
1900 rec
->flags
|= FTRACE_FL_IPMODIFY
;
1901 } else /* Removed entry */
1902 rec
->flags
&= ~FTRACE_FL_IPMODIFY
;
1903 } while_for_each_ftrace_rec();
1910 /* Roll back what we did above */
1911 do_for_each_ftrace_rec(pg
, rec
) {
1913 if (rec
->flags
& FTRACE_FL_DISABLED
)
1919 in_old
= !!ftrace_lookup_ip(old_hash
, rec
->ip
);
1920 in_new
= !!ftrace_lookup_ip(new_hash
, rec
->ip
);
1921 if (in_old
== in_new
)
1925 rec
->flags
&= ~FTRACE_FL_IPMODIFY
;
1927 rec
->flags
|= FTRACE_FL_IPMODIFY
;
1928 } while_for_each_ftrace_rec();
1934 static int ftrace_hash_ipmodify_enable(struct ftrace_ops
*ops
)
1936 struct ftrace_hash
*hash
= ops
->func_hash
->filter_hash
;
1938 if (ftrace_hash_empty(hash
))
1941 return __ftrace_hash_update_ipmodify(ops
, EMPTY_HASH
, hash
);
1944 /* Disabling always succeeds */
1945 static void ftrace_hash_ipmodify_disable(struct ftrace_ops
*ops
)
1947 struct ftrace_hash
*hash
= ops
->func_hash
->filter_hash
;
1949 if (ftrace_hash_empty(hash
))
1952 __ftrace_hash_update_ipmodify(ops
, hash
, EMPTY_HASH
);
1955 static int ftrace_hash_ipmodify_update(struct ftrace_ops
*ops
,
1956 struct ftrace_hash
*new_hash
)
1958 struct ftrace_hash
*old_hash
= ops
->func_hash
->filter_hash
;
1960 if (ftrace_hash_empty(old_hash
))
1963 if (ftrace_hash_empty(new_hash
))
1966 return __ftrace_hash_update_ipmodify(ops
, old_hash
, new_hash
);
1969 static void print_ip_ins(const char *fmt
, const unsigned char *p
)
1971 char ins
[MCOUNT_INSN_SIZE
];
1974 if (copy_from_kernel_nofault(ins
, p
, MCOUNT_INSN_SIZE
)) {
1975 printk(KERN_CONT
"%s[FAULT] %px\n", fmt
, p
);
1979 printk(KERN_CONT
"%s", fmt
);
1981 for (i
= 0; i
< MCOUNT_INSN_SIZE
; i
++)
1982 printk(KERN_CONT
"%s%02x", i
? ":" : "", ins
[i
]);
1985 enum ftrace_bug_type ftrace_bug_type
;
1986 const void *ftrace_expected
;
1988 static void print_bug_type(void)
1990 switch (ftrace_bug_type
) {
1991 case FTRACE_BUG_UNKNOWN
:
1993 case FTRACE_BUG_INIT
:
1994 pr_info("Initializing ftrace call sites\n");
1996 case FTRACE_BUG_NOP
:
1997 pr_info("Setting ftrace call site to NOP\n");
1999 case FTRACE_BUG_CALL
:
2000 pr_info("Setting ftrace call site to call ftrace function\n");
2002 case FTRACE_BUG_UPDATE
:
2003 pr_info("Updating ftrace call site to call a different ftrace function\n");
2009 * ftrace_bug - report and shutdown function tracer
2010 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2011 * @rec: The record that failed
2013 * The arch code that enables or disables the function tracing
2014 * can call ftrace_bug() when it has detected a problem in
2015 * modifying the code. @failed should be one of either:
2016 * EFAULT - if the problem happens on reading the @ip address
2017 * EINVAL - if what is read at @ip is not what was expected
2018 * EPERM - if the problem happens on writing to the @ip address
2020 void ftrace_bug(int failed
, struct dyn_ftrace
*rec
)
2022 unsigned long ip
= rec
? rec
->ip
: 0;
2024 pr_info("------------[ ftrace bug ]------------\n");
2028 pr_info("ftrace faulted on modifying ");
2029 print_ip_sym(KERN_INFO
, ip
);
2032 pr_info("ftrace failed to modify ");
2033 print_ip_sym(KERN_INFO
, ip
);
2034 print_ip_ins(" actual: ", (unsigned char *)ip
);
2036 if (ftrace_expected
) {
2037 print_ip_ins(" expected: ", ftrace_expected
);
2042 pr_info("ftrace faulted on writing ");
2043 print_ip_sym(KERN_INFO
, ip
);
2046 pr_info("ftrace faulted on unknown error ");
2047 print_ip_sym(KERN_INFO
, ip
);
2051 struct ftrace_ops
*ops
= NULL
;
2053 pr_info("ftrace record flags: %lx\n", rec
->flags
);
2054 pr_cont(" (%ld)%s", ftrace_rec_count(rec
),
2055 rec
->flags
& FTRACE_FL_REGS
? " R" : " ");
2056 if (rec
->flags
& FTRACE_FL_TRAMP_EN
) {
2057 ops
= ftrace_find_tramp_ops_any(rec
);
2060 pr_cont("\ttramp: %pS (%pS)",
2061 (void *)ops
->trampoline
,
2063 ops
= ftrace_find_tramp_ops_next(rec
, ops
);
2066 pr_cont("\ttramp: ERROR!");
2069 ip
= ftrace_get_addr_curr(rec
);
2070 pr_cont("\n expected tramp: %lx\n", ip
);
2073 FTRACE_WARN_ON_ONCE(1);
2076 static int ftrace_check_record(struct dyn_ftrace
*rec
, bool enable
, bool update
)
2078 unsigned long flag
= 0UL;
2080 ftrace_bug_type
= FTRACE_BUG_UNKNOWN
;
2082 if (rec
->flags
& FTRACE_FL_DISABLED
)
2083 return FTRACE_UPDATE_IGNORE
;
2086 * If we are updating calls:
2088 * If the record has a ref count, then we need to enable it
2089 * because someone is using it.
2091 * Otherwise we make sure its disabled.
2093 * If we are disabling calls, then disable all records that
2096 if (enable
&& ftrace_rec_count(rec
))
2097 flag
= FTRACE_FL_ENABLED
;
2100 * If enabling and the REGS flag does not match the REGS_EN, or
2101 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2102 * this record. Set flags to fail the compare against ENABLED.
2103 * Same for direct calls.
2106 if (!(rec
->flags
& FTRACE_FL_REGS
) !=
2107 !(rec
->flags
& FTRACE_FL_REGS_EN
))
2108 flag
|= FTRACE_FL_REGS
;
2110 if (!(rec
->flags
& FTRACE_FL_TRAMP
) !=
2111 !(rec
->flags
& FTRACE_FL_TRAMP_EN
))
2112 flag
|= FTRACE_FL_TRAMP
;
2115 * Direct calls are special, as count matters.
2116 * We must test the record for direct, if the
2117 * DIRECT and DIRECT_EN do not match, but only
2118 * if the count is 1. That's because, if the
2119 * count is something other than one, we do not
2120 * want the direct enabled (it will be done via the
2121 * direct helper). But if DIRECT_EN is set, and
2122 * the count is not one, we need to clear it.
2124 if (ftrace_rec_count(rec
) == 1) {
2125 if (!(rec
->flags
& FTRACE_FL_DIRECT
) !=
2126 !(rec
->flags
& FTRACE_FL_DIRECT_EN
))
2127 flag
|= FTRACE_FL_DIRECT
;
2128 } else if (rec
->flags
& FTRACE_FL_DIRECT_EN
) {
2129 flag
|= FTRACE_FL_DIRECT
;
2133 /* If the state of this record hasn't changed, then do nothing */
2134 if ((rec
->flags
& FTRACE_FL_ENABLED
) == flag
)
2135 return FTRACE_UPDATE_IGNORE
;
2138 /* Save off if rec is being enabled (for return value) */
2139 flag
^= rec
->flags
& FTRACE_FL_ENABLED
;
2142 rec
->flags
|= FTRACE_FL_ENABLED
;
2143 if (flag
& FTRACE_FL_REGS
) {
2144 if (rec
->flags
& FTRACE_FL_REGS
)
2145 rec
->flags
|= FTRACE_FL_REGS_EN
;
2147 rec
->flags
&= ~FTRACE_FL_REGS_EN
;
2149 if (flag
& FTRACE_FL_TRAMP
) {
2150 if (rec
->flags
& FTRACE_FL_TRAMP
)
2151 rec
->flags
|= FTRACE_FL_TRAMP_EN
;
2153 rec
->flags
&= ~FTRACE_FL_TRAMP_EN
;
2156 if (flag
& FTRACE_FL_DIRECT
) {
2158 * If there's only one user (direct_ops helper)
2159 * then we can call the direct function
2160 * directly (no ftrace trampoline).
2162 if (ftrace_rec_count(rec
) == 1) {
2163 if (rec
->flags
& FTRACE_FL_DIRECT
)
2164 rec
->flags
|= FTRACE_FL_DIRECT_EN
;
2166 rec
->flags
&= ~FTRACE_FL_DIRECT_EN
;
2169 * Can only call directly if there's
2170 * only one callback to the function.
2172 rec
->flags
&= ~FTRACE_FL_DIRECT_EN
;
2178 * If this record is being updated from a nop, then
2179 * return UPDATE_MAKE_CALL.
2181 * return UPDATE_MODIFY_CALL to tell the caller to convert
2182 * from the save regs, to a non-save regs function or
2183 * vice versa, or from a trampoline call.
2185 if (flag
& FTRACE_FL_ENABLED
) {
2186 ftrace_bug_type
= FTRACE_BUG_CALL
;
2187 return FTRACE_UPDATE_MAKE_CALL
;
2190 ftrace_bug_type
= FTRACE_BUG_UPDATE
;
2191 return FTRACE_UPDATE_MODIFY_CALL
;
2195 /* If there's no more users, clear all flags */
2196 if (!ftrace_rec_count(rec
))
2200 * Just disable the record, but keep the ops TRAMP
2201 * and REGS states. The _EN flags must be disabled though.
2203 rec
->flags
&= ~(FTRACE_FL_ENABLED
| FTRACE_FL_TRAMP_EN
|
2204 FTRACE_FL_REGS_EN
| FTRACE_FL_DIRECT_EN
);
2207 ftrace_bug_type
= FTRACE_BUG_NOP
;
2208 return FTRACE_UPDATE_MAKE_NOP
;
2212 * ftrace_update_record - set a record that now is tracing or not
2213 * @rec: the record to update
2214 * @enable: set to true if the record is tracing, false to force disable
2216 * The records that represent all functions that can be traced need
2217 * to be updated when tracing has been enabled.
2219 int ftrace_update_record(struct dyn_ftrace
*rec
, bool enable
)
2221 return ftrace_check_record(rec
, enable
, true);
2225 * ftrace_test_record - check if the record has been enabled or not
2226 * @rec: the record to test
2227 * @enable: set to true to check if enabled, false if it is disabled
2229 * The arch code may need to test if a record is already set to
2230 * tracing to determine how to modify the function code that it
2233 int ftrace_test_record(struct dyn_ftrace
*rec
, bool enable
)
2235 return ftrace_check_record(rec
, enable
, false);
2238 static struct ftrace_ops
*
2239 ftrace_find_tramp_ops_any(struct dyn_ftrace
*rec
)
2241 struct ftrace_ops
*op
;
2242 unsigned long ip
= rec
->ip
;
2244 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
2246 if (!op
->trampoline
)
2249 if (hash_contains_ip(ip
, op
->func_hash
))
2251 } while_for_each_ftrace_op(op
);
2256 static struct ftrace_ops
*
2257 ftrace_find_tramp_ops_any_other(struct dyn_ftrace
*rec
, struct ftrace_ops
*op_exclude
)
2259 struct ftrace_ops
*op
;
2260 unsigned long ip
= rec
->ip
;
2262 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
2264 if (op
== op_exclude
|| !op
->trampoline
)
2267 if (hash_contains_ip(ip
, op
->func_hash
))
2269 } while_for_each_ftrace_op(op
);
2274 static struct ftrace_ops
*
2275 ftrace_find_tramp_ops_next(struct dyn_ftrace
*rec
,
2276 struct ftrace_ops
*op
)
2278 unsigned long ip
= rec
->ip
;
2280 while_for_each_ftrace_op(op
) {
2282 if (!op
->trampoline
)
2285 if (hash_contains_ip(ip
, op
->func_hash
))
2292 static struct ftrace_ops
*
2293 ftrace_find_tramp_ops_curr(struct dyn_ftrace
*rec
)
2295 struct ftrace_ops
*op
;
2296 unsigned long ip
= rec
->ip
;
2299 * Need to check removed ops first.
2300 * If they are being removed, and this rec has a tramp,
2301 * and this rec is in the ops list, then it would be the
2302 * one with the tramp.
2305 if (hash_contains_ip(ip
, &removed_ops
->old_hash
))
2310 * Need to find the current trampoline for a rec.
2311 * Now, a trampoline is only attached to a rec if there
2312 * was a single 'ops' attached to it. But this can be called
2313 * when we are adding another op to the rec or removing the
2314 * current one. Thus, if the op is being added, we can
2315 * ignore it because it hasn't attached itself to the rec
2318 * If an ops is being modified (hooking to different functions)
2319 * then we don't care about the new functions that are being
2320 * added, just the old ones (that are probably being removed).
2322 * If we are adding an ops to a function that already is using
2323 * a trampoline, it needs to be removed (trampolines are only
2324 * for single ops connected), then an ops that is not being
2325 * modified also needs to be checked.
2327 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
2329 if (!op
->trampoline
)
2333 * If the ops is being added, it hasn't gotten to
2334 * the point to be removed from this tree yet.
2336 if (op
->flags
& FTRACE_OPS_FL_ADDING
)
2341 * If the ops is being modified and is in the old
2342 * hash, then it is probably being removed from this
2345 if ((op
->flags
& FTRACE_OPS_FL_MODIFYING
) &&
2346 hash_contains_ip(ip
, &op
->old_hash
))
2349 * If the ops is not being added or modified, and it's
2350 * in its normal filter hash, then this must be the one
2353 if (!(op
->flags
& FTRACE_OPS_FL_MODIFYING
) &&
2354 hash_contains_ip(ip
, op
->func_hash
))
2357 } while_for_each_ftrace_op(op
);
2362 static struct ftrace_ops
*
2363 ftrace_find_tramp_ops_new(struct dyn_ftrace
*rec
)
2365 struct ftrace_ops
*op
;
2366 unsigned long ip
= rec
->ip
;
2368 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
2369 /* pass rec in as regs to have non-NULL val */
2370 if (hash_contains_ip(ip
, op
->func_hash
))
2372 } while_for_each_ftrace_op(op
);
2377 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
2378 /* Protected by rcu_tasks for reading, and direct_mutex for writing */
2379 static struct ftrace_hash
*direct_functions
= EMPTY_HASH
;
2380 static DEFINE_MUTEX(direct_mutex
);
2381 int ftrace_direct_func_count
;
2384 * Search the direct_functions hash to see if the given instruction pointer
2385 * has a direct caller attached to it.
2387 unsigned long ftrace_find_rec_direct(unsigned long ip
)
2389 struct ftrace_func_entry
*entry
;
2391 entry
= __ftrace_lookup_ip(direct_functions
, ip
);
2395 return entry
->direct
;
2398 static void call_direct_funcs(unsigned long ip
, unsigned long pip
,
2399 struct ftrace_ops
*ops
, struct ftrace_regs
*fregs
)
2401 struct pt_regs
*regs
= ftrace_get_regs(fregs
);
2404 addr
= ftrace_find_rec_direct(ip
);
2408 arch_ftrace_set_direct_caller(regs
, addr
);
2411 struct ftrace_ops direct_ops
= {
2412 .func
= call_direct_funcs
,
2413 .flags
= FTRACE_OPS_FL_IPMODIFY
2414 | FTRACE_OPS_FL_DIRECT
| FTRACE_OPS_FL_SAVE_REGS
2415 | FTRACE_OPS_FL_PERMANENT
,
2417 * By declaring the main trampoline as this trampoline
2418 * it will never have one allocated for it. Allocated
2419 * trampolines should not call direct functions.
2420 * The direct_ops should only be called by the builtin
2421 * ftrace_regs_caller trampoline.
2423 .trampoline
= FTRACE_REGS_ADDR
,
2425 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
2428 * ftrace_get_addr_new - Get the call address to set to
2429 * @rec: The ftrace record descriptor
2431 * If the record has the FTRACE_FL_REGS set, that means that it
2432 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2433 * is not set, then it wants to convert to the normal callback.
2435 * Returns the address of the trampoline to set to
2437 unsigned long ftrace_get_addr_new(struct dyn_ftrace
*rec
)
2439 struct ftrace_ops
*ops
;
2442 if ((rec
->flags
& FTRACE_FL_DIRECT
) &&
2443 (ftrace_rec_count(rec
) == 1)) {
2444 addr
= ftrace_find_rec_direct(rec
->ip
);
2450 /* Trampolines take precedence over regs */
2451 if (rec
->flags
& FTRACE_FL_TRAMP
) {
2452 ops
= ftrace_find_tramp_ops_new(rec
);
2453 if (FTRACE_WARN_ON(!ops
|| !ops
->trampoline
)) {
2454 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2455 (void *)rec
->ip
, (void *)rec
->ip
, rec
->flags
);
2456 /* Ftrace is shutting down, return anything */
2457 return (unsigned long)FTRACE_ADDR
;
2459 return ops
->trampoline
;
2462 if (rec
->flags
& FTRACE_FL_REGS
)
2463 return (unsigned long)FTRACE_REGS_ADDR
;
2465 return (unsigned long)FTRACE_ADDR
;
2469 * ftrace_get_addr_curr - Get the call address that is already there
2470 * @rec: The ftrace record descriptor
2472 * The FTRACE_FL_REGS_EN is set when the record already points to
2473 * a function that saves all the regs. Basically the '_EN' version
2474 * represents the current state of the function.
2476 * Returns the address of the trampoline that is currently being called
2478 unsigned long ftrace_get_addr_curr(struct dyn_ftrace
*rec
)
2480 struct ftrace_ops
*ops
;
2483 /* Direct calls take precedence over trampolines */
2484 if (rec
->flags
& FTRACE_FL_DIRECT_EN
) {
2485 addr
= ftrace_find_rec_direct(rec
->ip
);
2491 /* Trampolines take precedence over regs */
2492 if (rec
->flags
& FTRACE_FL_TRAMP_EN
) {
2493 ops
= ftrace_find_tramp_ops_curr(rec
);
2494 if (FTRACE_WARN_ON(!ops
)) {
2495 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2496 (void *)rec
->ip
, (void *)rec
->ip
);
2497 /* Ftrace is shutting down, return anything */
2498 return (unsigned long)FTRACE_ADDR
;
2500 return ops
->trampoline
;
2503 if (rec
->flags
& FTRACE_FL_REGS_EN
)
2504 return (unsigned long)FTRACE_REGS_ADDR
;
2506 return (unsigned long)FTRACE_ADDR
;
2510 __ftrace_replace_code(struct dyn_ftrace
*rec
, bool enable
)
2512 unsigned long ftrace_old_addr
;
2513 unsigned long ftrace_addr
;
2516 ftrace_addr
= ftrace_get_addr_new(rec
);
2518 /* This needs to be done before we call ftrace_update_record */
2519 ftrace_old_addr
= ftrace_get_addr_curr(rec
);
2521 ret
= ftrace_update_record(rec
, enable
);
2523 ftrace_bug_type
= FTRACE_BUG_UNKNOWN
;
2526 case FTRACE_UPDATE_IGNORE
:
2529 case FTRACE_UPDATE_MAKE_CALL
:
2530 ftrace_bug_type
= FTRACE_BUG_CALL
;
2531 return ftrace_make_call(rec
, ftrace_addr
);
2533 case FTRACE_UPDATE_MAKE_NOP
:
2534 ftrace_bug_type
= FTRACE_BUG_NOP
;
2535 return ftrace_make_nop(NULL
, rec
, ftrace_old_addr
);
2537 case FTRACE_UPDATE_MODIFY_CALL
:
2538 ftrace_bug_type
= FTRACE_BUG_UPDATE
;
2539 return ftrace_modify_call(rec
, ftrace_old_addr
, ftrace_addr
);
2542 return -1; /* unknown ftrace bug */
2545 void __weak
ftrace_replace_code(int mod_flags
)
2547 struct dyn_ftrace
*rec
;
2548 struct ftrace_page
*pg
;
2549 bool enable
= mod_flags
& FTRACE_MODIFY_ENABLE_FL
;
2550 int schedulable
= mod_flags
& FTRACE_MODIFY_MAY_SLEEP_FL
;
2553 if (unlikely(ftrace_disabled
))
2556 do_for_each_ftrace_rec(pg
, rec
) {
2558 if (rec
->flags
& FTRACE_FL_DISABLED
)
2561 failed
= __ftrace_replace_code(rec
, enable
);
2563 ftrace_bug(failed
, rec
);
2564 /* Stop processing */
2569 } while_for_each_ftrace_rec();
2572 struct ftrace_rec_iter
{
2573 struct ftrace_page
*pg
;
2578 * ftrace_rec_iter_start - start up iterating over traced functions
2580 * Returns an iterator handle that is used to iterate over all
2581 * the records that represent address locations where functions
2584 * May return NULL if no records are available.
2586 struct ftrace_rec_iter
*ftrace_rec_iter_start(void)
2589 * We only use a single iterator.
2590 * Protected by the ftrace_lock mutex.
2592 static struct ftrace_rec_iter ftrace_rec_iter
;
2593 struct ftrace_rec_iter
*iter
= &ftrace_rec_iter
;
2595 iter
->pg
= ftrace_pages_start
;
2598 /* Could have empty pages */
2599 while (iter
->pg
&& !iter
->pg
->index
)
2600 iter
->pg
= iter
->pg
->next
;
2609 * ftrace_rec_iter_next - get the next record to process.
2610 * @iter: The handle to the iterator.
2612 * Returns the next iterator after the given iterator @iter.
2614 struct ftrace_rec_iter
*ftrace_rec_iter_next(struct ftrace_rec_iter
*iter
)
2618 if (iter
->index
>= iter
->pg
->index
) {
2619 iter
->pg
= iter
->pg
->next
;
2622 /* Could have empty pages */
2623 while (iter
->pg
&& !iter
->pg
->index
)
2624 iter
->pg
= iter
->pg
->next
;
2634 * ftrace_rec_iter_record - get the record at the iterator location
2635 * @iter: The current iterator location
2637 * Returns the record that the current @iter is at.
2639 struct dyn_ftrace
*ftrace_rec_iter_record(struct ftrace_rec_iter
*iter
)
2641 return &iter
->pg
->records
[iter
->index
];
2645 ftrace_nop_initialize(struct module
*mod
, struct dyn_ftrace
*rec
)
2649 if (unlikely(ftrace_disabled
))
2652 ret
= ftrace_init_nop(mod
, rec
);
2654 ftrace_bug_type
= FTRACE_BUG_INIT
;
2655 ftrace_bug(ret
, rec
);
2662 * archs can override this function if they must do something
2663 * before the modifying code is performed.
2665 int __weak
ftrace_arch_code_modify_prepare(void)
2671 * archs can override this function if they must do something
2672 * after the modifying code is performed.
2674 int __weak
ftrace_arch_code_modify_post_process(void)
2679 void ftrace_modify_all_code(int command
)
2681 int update
= command
& FTRACE_UPDATE_TRACE_FUNC
;
2685 if (command
& FTRACE_MAY_SLEEP
)
2686 mod_flags
= FTRACE_MODIFY_MAY_SLEEP_FL
;
2689 * If the ftrace_caller calls a ftrace_ops func directly,
2690 * we need to make sure that it only traces functions it
2691 * expects to trace. When doing the switch of functions,
2692 * we need to update to the ftrace_ops_list_func first
2693 * before the transition between old and new calls are set,
2694 * as the ftrace_ops_list_func will check the ops hashes
2695 * to make sure the ops are having the right functions
2699 err
= ftrace_update_ftrace_func(ftrace_ops_list_func
);
2700 if (FTRACE_WARN_ON(err
))
2704 if (command
& FTRACE_UPDATE_CALLS
)
2705 ftrace_replace_code(mod_flags
| FTRACE_MODIFY_ENABLE_FL
);
2706 else if (command
& FTRACE_DISABLE_CALLS
)
2707 ftrace_replace_code(mod_flags
);
2709 if (update
&& ftrace_trace_function
!= ftrace_ops_list_func
) {
2710 function_trace_op
= set_function_trace_op
;
2712 /* If irqs are disabled, we are in stop machine */
2713 if (!irqs_disabled())
2714 smp_call_function(ftrace_sync_ipi
, NULL
, 1);
2715 err
= ftrace_update_ftrace_func(ftrace_trace_function
);
2716 if (FTRACE_WARN_ON(err
))
2720 if (command
& FTRACE_START_FUNC_RET
)
2721 err
= ftrace_enable_ftrace_graph_caller();
2722 else if (command
& FTRACE_STOP_FUNC_RET
)
2723 err
= ftrace_disable_ftrace_graph_caller();
2724 FTRACE_WARN_ON(err
);
2727 static int __ftrace_modify_code(void *data
)
2729 int *command
= data
;
2731 ftrace_modify_all_code(*command
);
2737 * ftrace_run_stop_machine - go back to the stop machine method
2738 * @command: The command to tell ftrace what to do
2740 * If an arch needs to fall back to the stop machine method, the
2741 * it can call this function.
2743 void ftrace_run_stop_machine(int command
)
2745 stop_machine(__ftrace_modify_code
, &command
, NULL
);
2749 * arch_ftrace_update_code - modify the code to trace or not trace
2750 * @command: The command that needs to be done
2752 * Archs can override this function if it does not need to
2753 * run stop_machine() to modify code.
2755 void __weak
arch_ftrace_update_code(int command
)
2757 ftrace_run_stop_machine(command
);
2760 static void ftrace_run_update_code(int command
)
2764 ret
= ftrace_arch_code_modify_prepare();
2765 FTRACE_WARN_ON(ret
);
2770 * By default we use stop_machine() to modify the code.
2771 * But archs can do what ever they want as long as it
2772 * is safe. The stop_machine() is the safest, but also
2773 * produces the most overhead.
2775 arch_ftrace_update_code(command
);
2777 ret
= ftrace_arch_code_modify_post_process();
2778 FTRACE_WARN_ON(ret
);
2781 static void ftrace_run_modify_code(struct ftrace_ops
*ops
, int command
,
2782 struct ftrace_ops_hash
*old_hash
)
2784 ops
->flags
|= FTRACE_OPS_FL_MODIFYING
;
2785 ops
->old_hash
.filter_hash
= old_hash
->filter_hash
;
2786 ops
->old_hash
.notrace_hash
= old_hash
->notrace_hash
;
2787 ftrace_run_update_code(command
);
2788 ops
->old_hash
.filter_hash
= NULL
;
2789 ops
->old_hash
.notrace_hash
= NULL
;
2790 ops
->flags
&= ~FTRACE_OPS_FL_MODIFYING
;
2793 static ftrace_func_t saved_ftrace_func
;
2794 static int ftrace_start_up
;
2796 void __weak
arch_ftrace_trampoline_free(struct ftrace_ops
*ops
)
2800 /* List of trace_ops that have allocated trampolines */
2801 static LIST_HEAD(ftrace_ops_trampoline_list
);
2803 static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops
*ops
)
2805 lockdep_assert_held(&ftrace_lock
);
2806 list_add_rcu(&ops
->list
, &ftrace_ops_trampoline_list
);
2809 static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops
*ops
)
2811 lockdep_assert_held(&ftrace_lock
);
2812 list_del_rcu(&ops
->list
);
2817 * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols
2818 * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is
2821 #define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace"
2822 #define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"
2824 static void ftrace_trampoline_free(struct ftrace_ops
*ops
)
2826 if (ops
&& (ops
->flags
& FTRACE_OPS_FL_ALLOC_TRAMP
) &&
2829 * Record the text poke event before the ksymbol unregister
2832 perf_event_text_poke((void *)ops
->trampoline
,
2833 (void *)ops
->trampoline
,
2834 ops
->trampoline_size
, NULL
, 0);
2835 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL
,
2836 ops
->trampoline
, ops
->trampoline_size
,
2837 true, FTRACE_TRAMPOLINE_SYM
);
2838 /* Remove from kallsyms after the perf events */
2839 ftrace_remove_trampoline_from_kallsyms(ops
);
2842 arch_ftrace_trampoline_free(ops
);
2845 static void ftrace_startup_enable(int command
)
2847 if (saved_ftrace_func
!= ftrace_trace_function
) {
2848 saved_ftrace_func
= ftrace_trace_function
;
2849 command
|= FTRACE_UPDATE_TRACE_FUNC
;
2852 if (!command
|| !ftrace_enabled
)
2855 ftrace_run_update_code(command
);
2858 static void ftrace_startup_all(int command
)
2860 update_all_ops
= true;
2861 ftrace_startup_enable(command
);
2862 update_all_ops
= false;
2865 int ftrace_startup(struct ftrace_ops
*ops
, int command
)
2869 if (unlikely(ftrace_disabled
))
2872 ret
= __register_ftrace_function(ops
);
2879 * Note that ftrace probes uses this to start up
2880 * and modify functions it will probe. But we still
2881 * set the ADDING flag for modification, as probes
2882 * do not have trampolines. If they add them in the
2883 * future, then the probes will need to distinguish
2884 * between adding and updating probes.
2886 ops
->flags
|= FTRACE_OPS_FL_ENABLED
| FTRACE_OPS_FL_ADDING
;
2888 ret
= ftrace_hash_ipmodify_enable(ops
);
2890 /* Rollback registration process */
2891 __unregister_ftrace_function(ops
);
2893 ops
->flags
&= ~FTRACE_OPS_FL_ENABLED
;
2894 if (ops
->flags
& FTRACE_OPS_FL_DYNAMIC
)
2895 ftrace_trampoline_free(ops
);
2899 if (ftrace_hash_rec_enable(ops
, 1))
2900 command
|= FTRACE_UPDATE_CALLS
;
2902 ftrace_startup_enable(command
);
2904 ops
->flags
&= ~FTRACE_OPS_FL_ADDING
;
2909 int ftrace_shutdown(struct ftrace_ops
*ops
, int command
)
2913 if (unlikely(ftrace_disabled
))
2916 ret
= __unregister_ftrace_function(ops
);
2922 * Just warn in case of unbalance, no need to kill ftrace, it's not
2923 * critical but the ftrace_call callers may be never nopped again after
2924 * further ftrace uses.
2926 WARN_ON_ONCE(ftrace_start_up
< 0);
2928 /* Disabling ipmodify never fails */
2929 ftrace_hash_ipmodify_disable(ops
);
2931 if (ftrace_hash_rec_disable(ops
, 1))
2932 command
|= FTRACE_UPDATE_CALLS
;
2934 ops
->flags
&= ~FTRACE_OPS_FL_ENABLED
;
2936 if (saved_ftrace_func
!= ftrace_trace_function
) {
2937 saved_ftrace_func
= ftrace_trace_function
;
2938 command
|= FTRACE_UPDATE_TRACE_FUNC
;
2941 if (!command
|| !ftrace_enabled
) {
2943 * If these are dynamic or per_cpu ops, they still
2944 * need their data freed. Since, function tracing is
2945 * not currently active, we can just free them
2946 * without synchronizing all CPUs.
2948 if (ops
->flags
& FTRACE_OPS_FL_DYNAMIC
)
2955 * If the ops uses a trampoline, then it needs to be
2956 * tested first on update.
2958 ops
->flags
|= FTRACE_OPS_FL_REMOVING
;
2961 /* The trampoline logic checks the old hashes */
2962 ops
->old_hash
.filter_hash
= ops
->func_hash
->filter_hash
;
2963 ops
->old_hash
.notrace_hash
= ops
->func_hash
->notrace_hash
;
2965 ftrace_run_update_code(command
);
2968 * If there's no more ops registered with ftrace, run a
2969 * sanity check to make sure all rec flags are cleared.
2971 if (rcu_dereference_protected(ftrace_ops_list
,
2972 lockdep_is_held(&ftrace_lock
)) == &ftrace_list_end
) {
2973 struct ftrace_page
*pg
;
2974 struct dyn_ftrace
*rec
;
2976 do_for_each_ftrace_rec(pg
, rec
) {
2977 if (FTRACE_WARN_ON_ONCE(rec
->flags
& ~FTRACE_FL_DISABLED
))
2978 pr_warn(" %pS flags:%lx\n",
2979 (void *)rec
->ip
, rec
->flags
);
2980 } while_for_each_ftrace_rec();
2983 ops
->old_hash
.filter_hash
= NULL
;
2984 ops
->old_hash
.notrace_hash
= NULL
;
2987 ops
->flags
&= ~FTRACE_OPS_FL_REMOVING
;
2990 * Dynamic ops may be freed, we must make sure that all
2991 * callers are done before leaving this function.
2992 * The same goes for freeing the per_cpu data of the per_cpu
2995 if (ops
->flags
& FTRACE_OPS_FL_DYNAMIC
) {
2997 * We need to do a hard force of sched synchronization.
2998 * This is because we use preempt_disable() to do RCU, but
2999 * the function tracers can be called where RCU is not watching
3000 * (like before user_exit()). We can not rely on the RCU
3001 * infrastructure to do the synchronization, thus we must do it
3004 synchronize_rcu_tasks_rude();
3007 * When the kernel is preemptive, tasks can be preempted
3008 * while on a ftrace trampoline. Just scheduling a task on
3009 * a CPU is not good enough to flush them. Calling
3010 * synchronize_rcu_tasks() will wait for those tasks to
3011 * execute and either schedule voluntarily or enter user space.
3013 if (IS_ENABLED(CONFIG_PREEMPTION
))
3014 synchronize_rcu_tasks();
3017 ftrace_trampoline_free(ops
);
3023 static void ftrace_startup_sysctl(void)
3027 if (unlikely(ftrace_disabled
))
3030 /* Force update next time */
3031 saved_ftrace_func
= NULL
;
3032 /* ftrace_start_up is true if we want ftrace running */
3033 if (ftrace_start_up
) {
3034 command
= FTRACE_UPDATE_CALLS
;
3035 if (ftrace_graph_active
)
3036 command
|= FTRACE_START_FUNC_RET
;
3037 ftrace_startup_enable(command
);
3041 static void ftrace_shutdown_sysctl(void)
3045 if (unlikely(ftrace_disabled
))
3048 /* ftrace_start_up is true if ftrace is running */
3049 if (ftrace_start_up
) {
3050 command
= FTRACE_DISABLE_CALLS
;
3051 if (ftrace_graph_active
)
3052 command
|= FTRACE_STOP_FUNC_RET
;
3053 ftrace_run_update_code(command
);
3057 static u64 ftrace_update_time
;
3058 unsigned long ftrace_update_tot_cnt
;
3059 unsigned long ftrace_number_of_pages
;
3060 unsigned long ftrace_number_of_groups
;
3062 static inline int ops_traces_mod(struct ftrace_ops
*ops
)
3065 * Filter_hash being empty will default to trace module.
3066 * But notrace hash requires a test of individual module functions.
3068 return ftrace_hash_empty(ops
->func_hash
->filter_hash
) &&
3069 ftrace_hash_empty(ops
->func_hash
->notrace_hash
);
3073 * Check if the current ops references the record.
3075 * If the ops traces all functions, then it was already accounted for.
3076 * If the ops does not trace the current record function, skip it.
3077 * If the ops ignores the function via notrace filter, skip it.
3080 ops_references_rec(struct ftrace_ops
*ops
, struct dyn_ftrace
*rec
)
3082 /* If ops isn't enabled, ignore it */
3083 if (!(ops
->flags
& FTRACE_OPS_FL_ENABLED
))
3086 /* If ops traces all then it includes this function */
3087 if (ops_traces_mod(ops
))
3090 /* The function must be in the filter */
3091 if (!ftrace_hash_empty(ops
->func_hash
->filter_hash
) &&
3092 !__ftrace_lookup_ip(ops
->func_hash
->filter_hash
, rec
->ip
))
3095 /* If in notrace hash, we ignore it too */
3096 if (ftrace_lookup_ip(ops
->func_hash
->notrace_hash
, rec
->ip
))
3102 static int ftrace_update_code(struct module
*mod
, struct ftrace_page
*new_pgs
)
3104 bool init_nop
= ftrace_need_init_nop();
3105 struct ftrace_page
*pg
;
3106 struct dyn_ftrace
*p
;
3108 unsigned long update_cnt
= 0;
3109 unsigned long rec_flags
= 0;
3112 start
= ftrace_now(raw_smp_processor_id());
3115 * When a module is loaded, this function is called to convert
3116 * the calls to mcount in its text to nops, and also to create
3117 * an entry in the ftrace data. Now, if ftrace is activated
3118 * after this call, but before the module sets its text to
3119 * read-only, the modification of enabling ftrace can fail if
3120 * the read-only is done while ftrace is converting the calls.
3121 * To prevent this, the module's records are set as disabled
3122 * and will be enabled after the call to set the module's text
3126 rec_flags
|= FTRACE_FL_DISABLED
;
3128 for (pg
= new_pgs
; pg
; pg
= pg
->next
) {
3130 for (i
= 0; i
< pg
->index
; i
++) {
3132 /* If something went wrong, bail without enabling anything */
3133 if (unlikely(ftrace_disabled
))
3136 p
= &pg
->records
[i
];
3137 p
->flags
= rec_flags
;
3140 * Do the initial record conversion from mcount jump
3141 * to the NOP instructions.
3143 if (init_nop
&& !ftrace_nop_initialize(mod
, p
))
3150 stop
= ftrace_now(raw_smp_processor_id());
3151 ftrace_update_time
= stop
- start
;
3152 ftrace_update_tot_cnt
+= update_cnt
;
3157 static int ftrace_allocate_records(struct ftrace_page
*pg
, int count
)
3163 if (WARN_ON(!count
))
3166 /* We want to fill as much as possible, with no empty pages */
3167 pages
= DIV_ROUND_UP(count
, ENTRIES_PER_PAGE
);
3168 order
= fls(pages
) - 1;
3171 pg
->records
= (void *)__get_free_pages(GFP_KERNEL
| __GFP_ZERO
, order
);
3174 /* if we can't allocate this size, try something smaller */
3181 ftrace_number_of_pages
+= 1 << order
;
3182 ftrace_number_of_groups
++;
3184 cnt
= (PAGE_SIZE
<< order
) / ENTRY_SIZE
;
3193 static struct ftrace_page
*
3194 ftrace_allocate_pages(unsigned long num_to_init
)
3196 struct ftrace_page
*start_pg
;
3197 struct ftrace_page
*pg
;
3203 start_pg
= pg
= kzalloc(sizeof(*pg
), GFP_KERNEL
);
3208 * Try to allocate as much as possible in one continues
3209 * location that fills in all of the space. We want to
3210 * waste as little space as possible.
3213 cnt
= ftrace_allocate_records(pg
, num_to_init
);
3221 pg
->next
= kzalloc(sizeof(*pg
), GFP_KERNEL
);
3234 free_pages((unsigned long)pg
->records
, pg
->order
);
3235 ftrace_number_of_pages
-= 1 << pg
->order
;
3237 start_pg
= pg
->next
;
3240 ftrace_number_of_groups
--;
3242 pr_info("ftrace: FAILED to allocate memory for functions\n");
3246 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3248 struct ftrace_iterator
{
3252 struct ftrace_page
*pg
;
3253 struct dyn_ftrace
*func
;
3254 struct ftrace_func_probe
*probe
;
3255 struct ftrace_func_entry
*probe_entry
;
3256 struct trace_parser parser
;
3257 struct ftrace_hash
*hash
;
3258 struct ftrace_ops
*ops
;
3259 struct trace_array
*tr
;
3260 struct list_head
*mod_list
;
3267 t_probe_next(struct seq_file
*m
, loff_t
*pos
)
3269 struct ftrace_iterator
*iter
= m
->private;
3270 struct trace_array
*tr
= iter
->ops
->private;
3271 struct list_head
*func_probes
;
3272 struct ftrace_hash
*hash
;
3273 struct list_head
*next
;
3274 struct hlist_node
*hnd
= NULL
;
3275 struct hlist_head
*hhd
;
3284 func_probes
= &tr
->func_probes
;
3285 if (list_empty(func_probes
))
3289 next
= func_probes
->next
;
3290 iter
->probe
= list_entry(next
, struct ftrace_func_probe
, list
);
3293 if (iter
->probe_entry
)
3294 hnd
= &iter
->probe_entry
->hlist
;
3296 hash
= iter
->probe
->ops
.func_hash
->filter_hash
;
3299 * A probe being registered may temporarily have an empty hash
3300 * and it's at the end of the func_probes list.
3302 if (!hash
|| hash
== EMPTY_HASH
)
3305 size
= 1 << hash
->size_bits
;
3308 if (iter
->pidx
>= size
) {
3309 if (iter
->probe
->list
.next
== func_probes
)
3311 next
= iter
->probe
->list
.next
;
3312 iter
->probe
= list_entry(next
, struct ftrace_func_probe
, list
);
3313 hash
= iter
->probe
->ops
.func_hash
->filter_hash
;
3314 size
= 1 << hash
->size_bits
;
3318 hhd
= &hash
->buckets
[iter
->pidx
];
3320 if (hlist_empty(hhd
)) {
3336 if (WARN_ON_ONCE(!hnd
))
3339 iter
->probe_entry
= hlist_entry(hnd
, struct ftrace_func_entry
, hlist
);
3344 static void *t_probe_start(struct seq_file
*m
, loff_t
*pos
)
3346 struct ftrace_iterator
*iter
= m
->private;
3350 if (!(iter
->flags
& FTRACE_ITER_DO_PROBES
))
3353 if (iter
->mod_pos
> *pos
)
3357 iter
->probe_entry
= NULL
;
3359 for (l
= 0; l
<= (*pos
- iter
->mod_pos
); ) {
3360 p
= t_probe_next(m
, &l
);
3367 /* Only set this if we have an item */
3368 iter
->flags
|= FTRACE_ITER_PROBE
;
3374 t_probe_show(struct seq_file
*m
, struct ftrace_iterator
*iter
)
3376 struct ftrace_func_entry
*probe_entry
;
3377 struct ftrace_probe_ops
*probe_ops
;
3378 struct ftrace_func_probe
*probe
;
3380 probe
= iter
->probe
;
3381 probe_entry
= iter
->probe_entry
;
3383 if (WARN_ON_ONCE(!probe
|| !probe_entry
))
3386 probe_ops
= probe
->probe_ops
;
3388 if (probe_ops
->print
)
3389 return probe_ops
->print(m
, probe_entry
->ip
, probe_ops
, probe
->data
);
3391 seq_printf(m
, "%ps:%ps\n", (void *)probe_entry
->ip
,
3392 (void *)probe_ops
->func
);
3398 t_mod_next(struct seq_file
*m
, loff_t
*pos
)
3400 struct ftrace_iterator
*iter
= m
->private;
3401 struct trace_array
*tr
= iter
->tr
;
3406 iter
->mod_list
= iter
->mod_list
->next
;
3408 if (iter
->mod_list
== &tr
->mod_trace
||
3409 iter
->mod_list
== &tr
->mod_notrace
) {
3410 iter
->flags
&= ~FTRACE_ITER_MOD
;
3414 iter
->mod_pos
= *pos
;
3419 static void *t_mod_start(struct seq_file
*m
, loff_t
*pos
)
3421 struct ftrace_iterator
*iter
= m
->private;
3425 if (iter
->func_pos
> *pos
)
3428 iter
->mod_pos
= iter
->func_pos
;
3430 /* probes are only available if tr is set */
3434 for (l
= 0; l
<= (*pos
- iter
->func_pos
); ) {
3435 p
= t_mod_next(m
, &l
);
3440 iter
->flags
&= ~FTRACE_ITER_MOD
;
3441 return t_probe_start(m
, pos
);
3444 /* Only set this if we have an item */
3445 iter
->flags
|= FTRACE_ITER_MOD
;
3451 t_mod_show(struct seq_file
*m
, struct ftrace_iterator
*iter
)
3453 struct ftrace_mod_load
*ftrace_mod
;
3454 struct trace_array
*tr
= iter
->tr
;
3456 if (WARN_ON_ONCE(!iter
->mod_list
) ||
3457 iter
->mod_list
== &tr
->mod_trace
||
3458 iter
->mod_list
== &tr
->mod_notrace
)
3461 ftrace_mod
= list_entry(iter
->mod_list
, struct ftrace_mod_load
, list
);
3463 if (ftrace_mod
->func
)
3464 seq_printf(m
, "%s", ftrace_mod
->func
);
3468 seq_printf(m
, ":mod:%s\n", ftrace_mod
->module
);
3474 t_func_next(struct seq_file
*m
, loff_t
*pos
)
3476 struct ftrace_iterator
*iter
= m
->private;
3477 struct dyn_ftrace
*rec
= NULL
;
3482 if (iter
->idx
>= iter
->pg
->index
) {
3483 if (iter
->pg
->next
) {
3484 iter
->pg
= iter
->pg
->next
;
3489 rec
= &iter
->pg
->records
[iter
->idx
++];
3490 if (((iter
->flags
& (FTRACE_ITER_FILTER
| FTRACE_ITER_NOTRACE
)) &&
3491 !ftrace_lookup_ip(iter
->hash
, rec
->ip
)) ||
3493 ((iter
->flags
& FTRACE_ITER_ENABLED
) &&
3494 !(rec
->flags
& FTRACE_FL_ENABLED
))) {
3504 iter
->pos
= iter
->func_pos
= *pos
;
3511 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
3513 struct ftrace_iterator
*iter
= m
->private;
3514 loff_t l
= *pos
; /* t_probe_start() must use original pos */
3517 if (unlikely(ftrace_disabled
))
3520 if (iter
->flags
& FTRACE_ITER_PROBE
)
3521 return t_probe_next(m
, pos
);
3523 if (iter
->flags
& FTRACE_ITER_MOD
)
3524 return t_mod_next(m
, pos
);
3526 if (iter
->flags
& FTRACE_ITER_PRINTALL
) {
3527 /* next must increment pos, and t_probe_start does not */
3529 return t_mod_start(m
, &l
);
3532 ret
= t_func_next(m
, pos
);
3535 return t_mod_start(m
, &l
);
3540 static void reset_iter_read(struct ftrace_iterator
*iter
)
3544 iter
->flags
&= ~(FTRACE_ITER_PRINTALL
| FTRACE_ITER_PROBE
| FTRACE_ITER_MOD
);
3547 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
3549 struct ftrace_iterator
*iter
= m
->private;
3553 mutex_lock(&ftrace_lock
);
3555 if (unlikely(ftrace_disabled
))
3559 * If an lseek was done, then reset and start from beginning.
3561 if (*pos
< iter
->pos
)
3562 reset_iter_read(iter
);
3565 * For set_ftrace_filter reading, if we have the filter
3566 * off, we can short cut and just print out that all
3567 * functions are enabled.
3569 if ((iter
->flags
& (FTRACE_ITER_FILTER
| FTRACE_ITER_NOTRACE
)) &&
3570 ftrace_hash_empty(iter
->hash
)) {
3571 iter
->func_pos
= 1; /* Account for the message */
3573 return t_mod_start(m
, pos
);
3574 iter
->flags
|= FTRACE_ITER_PRINTALL
;
3575 /* reset in case of seek/pread */
3576 iter
->flags
&= ~FTRACE_ITER_PROBE
;
3580 if (iter
->flags
& FTRACE_ITER_MOD
)
3581 return t_mod_start(m
, pos
);
3584 * Unfortunately, we need to restart at ftrace_pages_start
3585 * every time we let go of the ftrace_mutex. This is because
3586 * those pointers can change without the lock.
3588 iter
->pg
= ftrace_pages_start
;
3590 for (l
= 0; l
<= *pos
; ) {
3591 p
= t_func_next(m
, &l
);
3597 return t_mod_start(m
, pos
);
3602 static void t_stop(struct seq_file
*m
, void *p
)
3604 mutex_unlock(&ftrace_lock
);
3608 arch_ftrace_trampoline_func(struct ftrace_ops
*ops
, struct dyn_ftrace
*rec
)
3613 static void add_trampoline_func(struct seq_file
*m
, struct ftrace_ops
*ops
,
3614 struct dyn_ftrace
*rec
)
3618 ptr
= arch_ftrace_trampoline_func(ops
, rec
);
3620 seq_printf(m
, " ->%pS", ptr
);
3623 static int t_show(struct seq_file
*m
, void *v
)
3625 struct ftrace_iterator
*iter
= m
->private;
3626 struct dyn_ftrace
*rec
;
3628 if (iter
->flags
& FTRACE_ITER_PROBE
)
3629 return t_probe_show(m
, iter
);
3631 if (iter
->flags
& FTRACE_ITER_MOD
)
3632 return t_mod_show(m
, iter
);
3634 if (iter
->flags
& FTRACE_ITER_PRINTALL
) {
3635 if (iter
->flags
& FTRACE_ITER_NOTRACE
)
3636 seq_puts(m
, "#### no functions disabled ####\n");
3638 seq_puts(m
, "#### all functions enabled ####\n");
3647 seq_printf(m
, "%ps", (void *)rec
->ip
);
3648 if (iter
->flags
& FTRACE_ITER_ENABLED
) {
3649 struct ftrace_ops
*ops
;
3651 seq_printf(m
, " (%ld)%s%s%s",
3652 ftrace_rec_count(rec
),
3653 rec
->flags
& FTRACE_FL_REGS
? " R" : " ",
3654 rec
->flags
& FTRACE_FL_IPMODIFY
? " I" : " ",
3655 rec
->flags
& FTRACE_FL_DIRECT
? " D" : " ");
3656 if (rec
->flags
& FTRACE_FL_TRAMP_EN
) {
3657 ops
= ftrace_find_tramp_ops_any(rec
);
3660 seq_printf(m
, "\ttramp: %pS (%pS)",
3661 (void *)ops
->trampoline
,
3663 add_trampoline_func(m
, ops
, rec
);
3664 ops
= ftrace_find_tramp_ops_next(rec
, ops
);
3667 seq_puts(m
, "\ttramp: ERROR!");
3669 add_trampoline_func(m
, NULL
, rec
);
3671 if (rec
->flags
& FTRACE_FL_DIRECT
) {
3672 unsigned long direct
;
3674 direct
= ftrace_find_rec_direct(rec
->ip
);
3676 seq_printf(m
, "\n\tdirect-->%pS", (void *)direct
);
3685 static const struct seq_operations show_ftrace_seq_ops
= {
3693 ftrace_avail_open(struct inode
*inode
, struct file
*file
)
3695 struct ftrace_iterator
*iter
;
3698 ret
= security_locked_down(LOCKDOWN_TRACEFS
);
3702 if (unlikely(ftrace_disabled
))
3705 iter
= __seq_open_private(file
, &show_ftrace_seq_ops
, sizeof(*iter
));
3709 iter
->pg
= ftrace_pages_start
;
3710 iter
->ops
= &global_ops
;
3716 ftrace_enabled_open(struct inode
*inode
, struct file
*file
)
3718 struct ftrace_iterator
*iter
;
3721 * This shows us what functions are currently being
3722 * traced and by what. Not sure if we want lockdown
3723 * to hide such critical information for an admin.
3724 * Although, perhaps it can show information we don't
3725 * want people to see, but if something is tracing
3726 * something, we probably want to know about it.
3729 iter
= __seq_open_private(file
, &show_ftrace_seq_ops
, sizeof(*iter
));
3733 iter
->pg
= ftrace_pages_start
;
3734 iter
->flags
= FTRACE_ITER_ENABLED
;
3735 iter
->ops
= &global_ops
;
3741 * ftrace_regex_open - initialize function tracer filter files
3742 * @ops: The ftrace_ops that hold the hash filters
3743 * @flag: The type of filter to process
3744 * @inode: The inode, usually passed in to your open routine
3745 * @file: The file, usually passed in to your open routine
3747 * ftrace_regex_open() initializes the filter files for the
3748 * @ops. Depending on @flag it may process the filter hash or
3749 * the notrace hash of @ops. With this called from the open
3750 * routine, you can use ftrace_filter_write() for the write
3751 * routine if @flag has FTRACE_ITER_FILTER set, or
3752 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3753 * tracing_lseek() should be used as the lseek routine, and
3754 * release must call ftrace_regex_release().
3757 ftrace_regex_open(struct ftrace_ops
*ops
, int flag
,
3758 struct inode
*inode
, struct file
*file
)
3760 struct ftrace_iterator
*iter
;
3761 struct ftrace_hash
*hash
;
3762 struct list_head
*mod_head
;
3763 struct trace_array
*tr
= ops
->private;
3766 ftrace_ops_init(ops
);
3768 if (unlikely(ftrace_disabled
))
3771 if (tracing_check_open_get_tr(tr
))
3774 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
3778 if (trace_parser_get_init(&iter
->parser
, FTRACE_BUFF_MAX
))
3785 mutex_lock(&ops
->func_hash
->regex_lock
);
3787 if (flag
& FTRACE_ITER_NOTRACE
) {
3788 hash
= ops
->func_hash
->notrace_hash
;
3789 mod_head
= tr
? &tr
->mod_notrace
: NULL
;
3791 hash
= ops
->func_hash
->filter_hash
;
3792 mod_head
= tr
? &tr
->mod_trace
: NULL
;
3795 iter
->mod_list
= mod_head
;
3797 if (file
->f_mode
& FMODE_WRITE
) {
3798 const int size_bits
= FTRACE_HASH_DEFAULT_BITS
;
3800 if (file
->f_flags
& O_TRUNC
) {
3801 iter
->hash
= alloc_ftrace_hash(size_bits
);
3802 clear_ftrace_mod_list(mod_head
);
3804 iter
->hash
= alloc_and_copy_ftrace_hash(size_bits
, hash
);
3808 trace_parser_put(&iter
->parser
);
3816 if (file
->f_mode
& FMODE_READ
) {
3817 iter
->pg
= ftrace_pages_start
;
3819 ret
= seq_open(file
, &show_ftrace_seq_ops
);
3821 struct seq_file
*m
= file
->private_data
;
3825 free_ftrace_hash(iter
->hash
);
3826 trace_parser_put(&iter
->parser
);
3829 file
->private_data
= iter
;
3832 mutex_unlock(&ops
->func_hash
->regex_lock
);
3838 trace_array_put(tr
);
3845 ftrace_filter_open(struct inode
*inode
, struct file
*file
)
3847 struct ftrace_ops
*ops
= inode
->i_private
;
3849 /* Checks for tracefs lockdown */
3850 return ftrace_regex_open(ops
,
3851 FTRACE_ITER_FILTER
| FTRACE_ITER_DO_PROBES
,
3856 ftrace_notrace_open(struct inode
*inode
, struct file
*file
)
3858 struct ftrace_ops
*ops
= inode
->i_private
;
3860 /* Checks for tracefs lockdown */
3861 return ftrace_regex_open(ops
, FTRACE_ITER_NOTRACE
,
3865 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3866 struct ftrace_glob
{
3873 * If symbols in an architecture don't correspond exactly to the user-visible
3874 * name of what they represent, it is possible to define this function to
3875 * perform the necessary adjustments.
3877 char * __weak
arch_ftrace_match_adjust(char *str
, const char *search
)
3882 static int ftrace_match(char *str
, struct ftrace_glob
*g
)
3887 str
= arch_ftrace_match_adjust(str
, g
->search
);
3891 if (strcmp(str
, g
->search
) == 0)
3894 case MATCH_FRONT_ONLY
:
3895 if (strncmp(str
, g
->search
, g
->len
) == 0)
3898 case MATCH_MIDDLE_ONLY
:
3899 if (strstr(str
, g
->search
))
3902 case MATCH_END_ONLY
:
3904 if (slen
>= g
->len
&&
3905 memcmp(str
+ slen
- g
->len
, g
->search
, g
->len
) == 0)
3909 if (glob_match(g
->search
, str
))
3918 enter_record(struct ftrace_hash
*hash
, struct dyn_ftrace
*rec
, int clear_filter
)
3920 struct ftrace_func_entry
*entry
;
3923 entry
= ftrace_lookup_ip(hash
, rec
->ip
);
3925 /* Do nothing if it doesn't exist */
3929 free_hash_entry(hash
, entry
);
3931 /* Do nothing if it exists */
3935 ret
= add_hash_entry(hash
, rec
->ip
);
3941 add_rec_by_index(struct ftrace_hash
*hash
, struct ftrace_glob
*func_g
,
3944 long index
= simple_strtoul(func_g
->search
, NULL
, 0);
3945 struct ftrace_page
*pg
;
3946 struct dyn_ftrace
*rec
;
3948 /* The index starts at 1 */
3952 do_for_each_ftrace_rec(pg
, rec
) {
3953 if (pg
->index
<= index
) {
3955 /* this is a double loop, break goes to the next page */
3958 rec
= &pg
->records
[index
];
3959 enter_record(hash
, rec
, clear_filter
);
3961 } while_for_each_ftrace_rec();
3966 ftrace_match_record(struct dyn_ftrace
*rec
, struct ftrace_glob
*func_g
,
3967 struct ftrace_glob
*mod_g
, int exclude_mod
)
3969 char str
[KSYM_SYMBOL_LEN
];
3972 kallsyms_lookup(rec
->ip
, NULL
, NULL
, &modname
, str
);
3975 int mod_matches
= (modname
) ? ftrace_match(modname
, mod_g
) : 0;
3977 /* blank module name to match all modules */
3979 /* blank module globbing: modname xor exclude_mod */
3980 if (!exclude_mod
!= !modname
)
3986 * exclude_mod is set to trace everything but the given
3987 * module. If it is set and the module matches, then
3988 * return 0. If it is not set, and the module doesn't match
3989 * also return 0. Otherwise, check the function to see if
3992 if (!mod_matches
== !exclude_mod
)
3995 /* blank search means to match all funcs in the mod */
4000 return ftrace_match(str
, func_g
);
4004 match_records(struct ftrace_hash
*hash
, char *func
, int len
, char *mod
)
4006 struct ftrace_page
*pg
;
4007 struct dyn_ftrace
*rec
;
4008 struct ftrace_glob func_g
= { .type
= MATCH_FULL
};
4009 struct ftrace_glob mod_g
= { .type
= MATCH_FULL
};
4010 struct ftrace_glob
*mod_match
= (mod
) ? &mod_g
: NULL
;
4011 int exclude_mod
= 0;
4014 int clear_filter
= 0;
4017 func_g
.type
= filter_parse_regex(func
, len
, &func_g
.search
,
4019 func_g
.len
= strlen(func_g
.search
);
4023 mod_g
.type
= filter_parse_regex(mod
, strlen(mod
),
4024 &mod_g
.search
, &exclude_mod
);
4025 mod_g
.len
= strlen(mod_g
.search
);
4028 mutex_lock(&ftrace_lock
);
4030 if (unlikely(ftrace_disabled
))
4033 if (func_g
.type
== MATCH_INDEX
) {
4034 found
= add_rec_by_index(hash
, &func_g
, clear_filter
);
4038 do_for_each_ftrace_rec(pg
, rec
) {
4040 if (rec
->flags
& FTRACE_FL_DISABLED
)
4043 if (ftrace_match_record(rec
, &func_g
, mod_match
, exclude_mod
)) {
4044 ret
= enter_record(hash
, rec
, clear_filter
);
4051 } while_for_each_ftrace_rec();
4053 mutex_unlock(&ftrace_lock
);
4059 ftrace_match_records(struct ftrace_hash
*hash
, char *buff
, int len
)
4061 return match_records(hash
, buff
, len
, NULL
);
4064 static void ftrace_ops_update_code(struct ftrace_ops
*ops
,
4065 struct ftrace_ops_hash
*old_hash
)
4067 struct ftrace_ops
*op
;
4069 if (!ftrace_enabled
)
4072 if (ops
->flags
& FTRACE_OPS_FL_ENABLED
) {
4073 ftrace_run_modify_code(ops
, FTRACE_UPDATE_CALLS
, old_hash
);
4078 * If this is the shared global_ops filter, then we need to
4079 * check if there is another ops that shares it, is enabled.
4080 * If so, we still need to run the modify code.
4082 if (ops
->func_hash
!= &global_ops
.local_hash
)
4085 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
4086 if (op
->func_hash
== &global_ops
.local_hash
&&
4087 op
->flags
& FTRACE_OPS_FL_ENABLED
) {
4088 ftrace_run_modify_code(op
, FTRACE_UPDATE_CALLS
, old_hash
);
4089 /* Only need to do this once */
4092 } while_for_each_ftrace_op(op
);
4095 static int ftrace_hash_move_and_update_ops(struct ftrace_ops
*ops
,
4096 struct ftrace_hash
**orig_hash
,
4097 struct ftrace_hash
*hash
,
4100 struct ftrace_ops_hash old_hash_ops
;
4101 struct ftrace_hash
*old_hash
;
4104 old_hash
= *orig_hash
;
4105 old_hash_ops
.filter_hash
= ops
->func_hash
->filter_hash
;
4106 old_hash_ops
.notrace_hash
= ops
->func_hash
->notrace_hash
;
4107 ret
= ftrace_hash_move(ops
, enable
, orig_hash
, hash
);
4109 ftrace_ops_update_code(ops
, &old_hash_ops
);
4110 free_ftrace_hash_rcu(old_hash
);
4115 static bool module_exists(const char *module
)
4117 /* All modules have the symbol __this_module */
4118 static const char this_mod
[] = "__this_module";
4119 char modname
[MAX_PARAM_PREFIX_LEN
+ sizeof(this_mod
) + 2];
4123 n
= snprintf(modname
, sizeof(modname
), "%s:%s", module
, this_mod
);
4125 if (n
> sizeof(modname
) - 1)
4128 val
= module_kallsyms_lookup_name(modname
);
4132 static int cache_mod(struct trace_array
*tr
,
4133 const char *func
, char *module
, int enable
)
4135 struct ftrace_mod_load
*ftrace_mod
, *n
;
4136 struct list_head
*head
= enable
? &tr
->mod_trace
: &tr
->mod_notrace
;
4139 mutex_lock(&ftrace_lock
);
4141 /* We do not cache inverse filters */
4142 if (func
[0] == '!') {
4146 /* Look to remove this hash */
4147 list_for_each_entry_safe(ftrace_mod
, n
, head
, list
) {
4148 if (strcmp(ftrace_mod
->module
, module
) != 0)
4151 /* no func matches all */
4152 if (strcmp(func
, "*") == 0 ||
4153 (ftrace_mod
->func
&&
4154 strcmp(ftrace_mod
->func
, func
) == 0)) {
4156 free_ftrace_mod(ftrace_mod
);
4164 /* We only care about modules that have not been loaded yet */
4165 if (module_exists(module
))
4168 /* Save this string off, and execute it when the module is loaded */
4169 ret
= ftrace_add_mod(tr
, func
, module
, enable
);
4171 mutex_unlock(&ftrace_lock
);
4177 ftrace_set_regex(struct ftrace_ops
*ops
, unsigned char *buf
, int len
,
4178 int reset
, int enable
);
4180 #ifdef CONFIG_MODULES
4181 static void process_mod_list(struct list_head
*head
, struct ftrace_ops
*ops
,
4182 char *mod
, bool enable
)
4184 struct ftrace_mod_load
*ftrace_mod
, *n
;
4185 struct ftrace_hash
**orig_hash
, *new_hash
;
4186 LIST_HEAD(process_mods
);
4189 mutex_lock(&ops
->func_hash
->regex_lock
);
4192 orig_hash
= &ops
->func_hash
->filter_hash
;
4194 orig_hash
= &ops
->func_hash
->notrace_hash
;
4196 new_hash
= alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
,
4199 goto out
; /* warn? */
4201 mutex_lock(&ftrace_lock
);
4203 list_for_each_entry_safe(ftrace_mod
, n
, head
, list
) {
4205 if (strcmp(ftrace_mod
->module
, mod
) != 0)
4208 if (ftrace_mod
->func
)
4209 func
= kstrdup(ftrace_mod
->func
, GFP_KERNEL
);
4211 func
= kstrdup("*", GFP_KERNEL
);
4213 if (!func
) /* warn? */
4216 list_move(&ftrace_mod
->list
, &process_mods
);
4218 /* Use the newly allocated func, as it may be "*" */
4219 kfree(ftrace_mod
->func
);
4220 ftrace_mod
->func
= func
;
4223 mutex_unlock(&ftrace_lock
);
4225 list_for_each_entry_safe(ftrace_mod
, n
, &process_mods
, list
) {
4227 func
= ftrace_mod
->func
;
4229 /* Grabs ftrace_lock, which is why we have this extra step */
4230 match_records(new_hash
, func
, strlen(func
), mod
);
4231 free_ftrace_mod(ftrace_mod
);
4234 if (enable
&& list_empty(head
))
4235 new_hash
->flags
&= ~FTRACE_HASH_FL_MOD
;
4237 mutex_lock(&ftrace_lock
);
4239 ftrace_hash_move_and_update_ops(ops
, orig_hash
,
4241 mutex_unlock(&ftrace_lock
);
4244 mutex_unlock(&ops
->func_hash
->regex_lock
);
4246 free_ftrace_hash(new_hash
);
4249 static void process_cached_mods(const char *mod_name
)
4251 struct trace_array
*tr
;
4254 mod
= kstrdup(mod_name
, GFP_KERNEL
);
4258 mutex_lock(&trace_types_lock
);
4259 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
4260 if (!list_empty(&tr
->mod_trace
))
4261 process_mod_list(&tr
->mod_trace
, tr
->ops
, mod
, true);
4262 if (!list_empty(&tr
->mod_notrace
))
4263 process_mod_list(&tr
->mod_notrace
, tr
->ops
, mod
, false);
4265 mutex_unlock(&trace_types_lock
);
4272 * We register the module command as a template to show others how
4273 * to register the a command as well.
4277 ftrace_mod_callback(struct trace_array
*tr
, struct ftrace_hash
*hash
,
4278 char *func_orig
, char *cmd
, char *module
, int enable
)
4283 /* match_records() modifies func, and we need the original */
4284 func
= kstrdup(func_orig
, GFP_KERNEL
);
4289 * cmd == 'mod' because we only registered this func
4290 * for the 'mod' ftrace_func_command.
4291 * But if you register one func with multiple commands,
4292 * you can tell which command was used by the cmd
4295 ret
= match_records(hash
, func
, strlen(func
), module
);
4299 return cache_mod(tr
, func_orig
, module
, enable
);
4305 static struct ftrace_func_command ftrace_mod_cmd
= {
4307 .func
= ftrace_mod_callback
,
4310 static int __init
ftrace_mod_cmd_init(void)
4312 return register_ftrace_command(&ftrace_mod_cmd
);
4314 core_initcall(ftrace_mod_cmd_init
);
4316 static void function_trace_probe_call(unsigned long ip
, unsigned long parent_ip
,
4317 struct ftrace_ops
*op
, struct ftrace_regs
*fregs
)
4319 struct ftrace_probe_ops
*probe_ops
;
4320 struct ftrace_func_probe
*probe
;
4322 probe
= container_of(op
, struct ftrace_func_probe
, ops
);
4323 probe_ops
= probe
->probe_ops
;
4326 * Disable preemption for these calls to prevent a RCU grace
4327 * period. This syncs the hash iteration and freeing of items
4328 * on the hash. rcu_read_lock is too dangerous here.
4330 preempt_disable_notrace();
4331 probe_ops
->func(ip
, parent_ip
, probe
->tr
, probe_ops
, probe
->data
);
4332 preempt_enable_notrace();
4335 struct ftrace_func_map
{
4336 struct ftrace_func_entry entry
;
4340 struct ftrace_func_mapper
{
4341 struct ftrace_hash hash
;
4345 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4347 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4349 struct ftrace_func_mapper
*allocate_ftrace_func_mapper(void)
4351 struct ftrace_hash
*hash
;
4354 * The mapper is simply a ftrace_hash, but since the entries
4355 * in the hash are not ftrace_func_entry type, we define it
4356 * as a separate structure.
4358 hash
= alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
);
4359 return (struct ftrace_func_mapper
*)hash
;
4363 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4364 * @mapper: The mapper that has the ip maps
4365 * @ip: the instruction pointer to find the data for
4367 * Returns the data mapped to @ip if found otherwise NULL. The return
4368 * is actually the address of the mapper data pointer. The address is
4369 * returned for use cases where the data is no bigger than a long, and
4370 * the user can use the data pointer as its data instead of having to
4371 * allocate more memory for the reference.
4373 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper
*mapper
,
4376 struct ftrace_func_entry
*entry
;
4377 struct ftrace_func_map
*map
;
4379 entry
= ftrace_lookup_ip(&mapper
->hash
, ip
);
4383 map
= (struct ftrace_func_map
*)entry
;
4388 * ftrace_func_mapper_add_ip - Map some data to an ip
4389 * @mapper: The mapper that has the ip maps
4390 * @ip: The instruction pointer address to map @data to
4391 * @data: The data to map to @ip
4393 * Returns 0 on success otherwise an error.
4395 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper
*mapper
,
4396 unsigned long ip
, void *data
)
4398 struct ftrace_func_entry
*entry
;
4399 struct ftrace_func_map
*map
;
4401 entry
= ftrace_lookup_ip(&mapper
->hash
, ip
);
4405 map
= kmalloc(sizeof(*map
), GFP_KERNEL
);
4412 __add_hash_entry(&mapper
->hash
, &map
->entry
);
4418 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4419 * @mapper: The mapper that has the ip maps
4420 * @ip: The instruction pointer address to remove the data from
4422 * Returns the data if it is found, otherwise NULL.
4423 * Note, if the data pointer is used as the data itself, (see
4424 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4425 * if the data pointer was set to zero.
4427 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper
*mapper
,
4430 struct ftrace_func_entry
*entry
;
4431 struct ftrace_func_map
*map
;
4434 entry
= ftrace_lookup_ip(&mapper
->hash
, ip
);
4438 map
= (struct ftrace_func_map
*)entry
;
4441 remove_hash_entry(&mapper
->hash
, entry
);
4448 * free_ftrace_func_mapper - free a mapping of ips and data
4449 * @mapper: The mapper that has the ip maps
4450 * @free_func: A function to be called on each data item.
4452 * This is used to free the function mapper. The @free_func is optional
4453 * and can be used if the data needs to be freed as well.
4455 void free_ftrace_func_mapper(struct ftrace_func_mapper
*mapper
,
4456 ftrace_mapper_func free_func
)
4458 struct ftrace_func_entry
*entry
;
4459 struct ftrace_func_map
*map
;
4460 struct hlist_head
*hhd
;
4466 if (free_func
&& mapper
->hash
.count
) {
4467 size
= 1 << mapper
->hash
.size_bits
;
4468 for (i
= 0; i
< size
; i
++) {
4469 hhd
= &mapper
->hash
.buckets
[i
];
4470 hlist_for_each_entry(entry
, hhd
, hlist
) {
4471 map
= (struct ftrace_func_map
*)entry
;
4476 free_ftrace_hash(&mapper
->hash
);
4479 static void release_probe(struct ftrace_func_probe
*probe
)
4481 struct ftrace_probe_ops
*probe_ops
;
4483 mutex_lock(&ftrace_lock
);
4485 WARN_ON(probe
->ref
<= 0);
4487 /* Subtract the ref that was used to protect this instance */
4491 probe_ops
= probe
->probe_ops
;
4493 * Sending zero as ip tells probe_ops to free
4494 * the probe->data itself
4496 if (probe_ops
->free
)
4497 probe_ops
->free(probe_ops
, probe
->tr
, 0, probe
->data
);
4498 list_del(&probe
->list
);
4501 mutex_unlock(&ftrace_lock
);
4504 static void acquire_probe_locked(struct ftrace_func_probe
*probe
)
4507 * Add one ref to keep it from being freed when releasing the
4508 * ftrace_lock mutex.
4514 register_ftrace_function_probe(char *glob
, struct trace_array
*tr
,
4515 struct ftrace_probe_ops
*probe_ops
,
4518 struct ftrace_func_entry
*entry
;
4519 struct ftrace_func_probe
*probe
;
4520 struct ftrace_hash
**orig_hash
;
4521 struct ftrace_hash
*old_hash
;
4522 struct ftrace_hash
*hash
;
4531 /* We do not support '!' for function probes */
4532 if (WARN_ON(glob
[0] == '!'))
4536 mutex_lock(&ftrace_lock
);
4537 /* Check if the probe_ops is already registered */
4538 list_for_each_entry(probe
, &tr
->func_probes
, list
) {
4539 if (probe
->probe_ops
== probe_ops
)
4542 if (&probe
->list
== &tr
->func_probes
) {
4543 probe
= kzalloc(sizeof(*probe
), GFP_KERNEL
);
4545 mutex_unlock(&ftrace_lock
);
4548 probe
->probe_ops
= probe_ops
;
4549 probe
->ops
.func
= function_trace_probe_call
;
4551 ftrace_ops_init(&probe
->ops
);
4552 list_add(&probe
->list
, &tr
->func_probes
);
4555 acquire_probe_locked(probe
);
4557 mutex_unlock(&ftrace_lock
);
4560 * Note, there's a small window here that the func_hash->filter_hash
4561 * may be NULL or empty. Need to be careful when reading the loop.
4563 mutex_lock(&probe
->ops
.func_hash
->regex_lock
);
4565 orig_hash
= &probe
->ops
.func_hash
->filter_hash
;
4566 old_hash
= *orig_hash
;
4567 hash
= alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
, old_hash
);
4574 ret
= ftrace_match_records(hash
, glob
, strlen(glob
));
4576 /* Nothing found? */
4583 size
= 1 << hash
->size_bits
;
4584 for (i
= 0; i
< size
; i
++) {
4585 hlist_for_each_entry(entry
, &hash
->buckets
[i
], hlist
) {
4586 if (ftrace_lookup_ip(old_hash
, entry
->ip
))
4589 * The caller might want to do something special
4590 * for each function we find. We call the callback
4591 * to give the caller an opportunity to do so.
4593 if (probe_ops
->init
) {
4594 ret
= probe_ops
->init(probe_ops
, tr
,
4598 if (probe_ops
->free
&& count
)
4599 probe_ops
->free(probe_ops
, tr
,
4609 mutex_lock(&ftrace_lock
);
4612 /* Nothing was added? */
4617 ret
= ftrace_hash_move_and_update_ops(&probe
->ops
, orig_hash
,
4622 /* One ref for each new function traced */
4623 probe
->ref
+= count
;
4625 if (!(probe
->ops
.flags
& FTRACE_OPS_FL_ENABLED
))
4626 ret
= ftrace_startup(&probe
->ops
, 0);
4629 mutex_unlock(&ftrace_lock
);
4634 mutex_unlock(&probe
->ops
.func_hash
->regex_lock
);
4635 free_ftrace_hash(hash
);
4637 release_probe(probe
);
4642 if (!probe_ops
->free
|| !count
)
4645 /* Failed to do the move, need to call the free functions */
4646 for (i
= 0; i
< size
; i
++) {
4647 hlist_for_each_entry(entry
, &hash
->buckets
[i
], hlist
) {
4648 if (ftrace_lookup_ip(old_hash
, entry
->ip
))
4650 probe_ops
->free(probe_ops
, tr
, entry
->ip
, probe
->data
);
4657 unregister_ftrace_function_probe_func(char *glob
, struct trace_array
*tr
,
4658 struct ftrace_probe_ops
*probe_ops
)
4660 struct ftrace_ops_hash old_hash_ops
;
4661 struct ftrace_func_entry
*entry
;
4662 struct ftrace_func_probe
*probe
;
4663 struct ftrace_glob func_g
;
4664 struct ftrace_hash
**orig_hash
;
4665 struct ftrace_hash
*old_hash
;
4666 struct ftrace_hash
*hash
= NULL
;
4667 struct hlist_node
*tmp
;
4668 struct hlist_head hhd
;
4669 char str
[KSYM_SYMBOL_LEN
];
4671 int i
, ret
= -ENODEV
;
4674 if (!glob
|| !strlen(glob
) || !strcmp(glob
, "*"))
4675 func_g
.search
= NULL
;
4679 func_g
.type
= filter_parse_regex(glob
, strlen(glob
),
4680 &func_g
.search
, ¬);
4681 func_g
.len
= strlen(func_g
.search
);
4683 /* we do not support '!' for function probes */
4688 mutex_lock(&ftrace_lock
);
4689 /* Check if the probe_ops is already registered */
4690 list_for_each_entry(probe
, &tr
->func_probes
, list
) {
4691 if (probe
->probe_ops
== probe_ops
)
4694 if (&probe
->list
== &tr
->func_probes
)
4695 goto err_unlock_ftrace
;
4698 if (!(probe
->ops
.flags
& FTRACE_OPS_FL_INITIALIZED
))
4699 goto err_unlock_ftrace
;
4701 acquire_probe_locked(probe
);
4703 mutex_unlock(&ftrace_lock
);
4705 mutex_lock(&probe
->ops
.func_hash
->regex_lock
);
4707 orig_hash
= &probe
->ops
.func_hash
->filter_hash
;
4708 old_hash
= *orig_hash
;
4710 if (ftrace_hash_empty(old_hash
))
4713 old_hash_ops
.filter_hash
= old_hash
;
4714 /* Probes only have filters */
4715 old_hash_ops
.notrace_hash
= NULL
;
4718 hash
= alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
, old_hash
);
4722 INIT_HLIST_HEAD(&hhd
);
4724 size
= 1 << hash
->size_bits
;
4725 for (i
= 0; i
< size
; i
++) {
4726 hlist_for_each_entry_safe(entry
, tmp
, &hash
->buckets
[i
], hlist
) {
4728 if (func_g
.search
) {
4729 kallsyms_lookup(entry
->ip
, NULL
, NULL
,
4731 if (!ftrace_match(str
, &func_g
))
4735 remove_hash_entry(hash
, entry
);
4736 hlist_add_head(&entry
->hlist
, &hhd
);
4740 /* Nothing found? */
4746 mutex_lock(&ftrace_lock
);
4748 WARN_ON(probe
->ref
< count
);
4750 probe
->ref
-= count
;
4752 if (ftrace_hash_empty(hash
))
4753 ftrace_shutdown(&probe
->ops
, 0);
4755 ret
= ftrace_hash_move_and_update_ops(&probe
->ops
, orig_hash
,
4758 /* still need to update the function call sites */
4759 if (ftrace_enabled
&& !ftrace_hash_empty(hash
))
4760 ftrace_run_modify_code(&probe
->ops
, FTRACE_UPDATE_CALLS
,
4764 hlist_for_each_entry_safe(entry
, tmp
, &hhd
, hlist
) {
4765 hlist_del(&entry
->hlist
);
4766 if (probe_ops
->free
)
4767 probe_ops
->free(probe_ops
, tr
, entry
->ip
, probe
->data
);
4770 mutex_unlock(&ftrace_lock
);
4773 mutex_unlock(&probe
->ops
.func_hash
->regex_lock
);
4774 free_ftrace_hash(hash
);
4776 release_probe(probe
);
4781 mutex_unlock(&ftrace_lock
);
4785 void clear_ftrace_function_probes(struct trace_array
*tr
)
4787 struct ftrace_func_probe
*probe
, *n
;
4789 list_for_each_entry_safe(probe
, n
, &tr
->func_probes
, list
)
4790 unregister_ftrace_function_probe_func(NULL
, tr
, probe
->probe_ops
);
4793 static LIST_HEAD(ftrace_commands
);
4794 static DEFINE_MUTEX(ftrace_cmd_mutex
);
4797 * Currently we only register ftrace commands from __init, so mark this
4800 __init
int register_ftrace_command(struct ftrace_func_command
*cmd
)
4802 struct ftrace_func_command
*p
;
4805 mutex_lock(&ftrace_cmd_mutex
);
4806 list_for_each_entry(p
, &ftrace_commands
, list
) {
4807 if (strcmp(cmd
->name
, p
->name
) == 0) {
4812 list_add(&cmd
->list
, &ftrace_commands
);
4814 mutex_unlock(&ftrace_cmd_mutex
);
4820 * Currently we only unregister ftrace commands from __init, so mark
4823 __init
int unregister_ftrace_command(struct ftrace_func_command
*cmd
)
4825 struct ftrace_func_command
*p
, *n
;
4828 mutex_lock(&ftrace_cmd_mutex
);
4829 list_for_each_entry_safe(p
, n
, &ftrace_commands
, list
) {
4830 if (strcmp(cmd
->name
, p
->name
) == 0) {
4832 list_del_init(&p
->list
);
4837 mutex_unlock(&ftrace_cmd_mutex
);
4842 static int ftrace_process_regex(struct ftrace_iterator
*iter
,
4843 char *buff
, int len
, int enable
)
4845 struct ftrace_hash
*hash
= iter
->hash
;
4846 struct trace_array
*tr
= iter
->ops
->private;
4847 char *func
, *command
, *next
= buff
;
4848 struct ftrace_func_command
*p
;
4851 func
= strsep(&next
, ":");
4854 ret
= ftrace_match_records(hash
, func
, len
);
4864 command
= strsep(&next
, ":");
4866 mutex_lock(&ftrace_cmd_mutex
);
4867 list_for_each_entry(p
, &ftrace_commands
, list
) {
4868 if (strcmp(p
->name
, command
) == 0) {
4869 ret
= p
->func(tr
, hash
, func
, command
, next
, enable
);
4874 mutex_unlock(&ftrace_cmd_mutex
);
4880 ftrace_regex_write(struct file
*file
, const char __user
*ubuf
,
4881 size_t cnt
, loff_t
*ppos
, int enable
)
4883 struct ftrace_iterator
*iter
;
4884 struct trace_parser
*parser
;
4890 if (file
->f_mode
& FMODE_READ
) {
4891 struct seq_file
*m
= file
->private_data
;
4894 iter
= file
->private_data
;
4896 if (unlikely(ftrace_disabled
))
4899 /* iter->hash is a local copy, so we don't need regex_lock */
4901 parser
= &iter
->parser
;
4902 read
= trace_get_user(parser
, ubuf
, cnt
, ppos
);
4904 if (read
>= 0 && trace_parser_loaded(parser
) &&
4905 !trace_parser_cont(parser
)) {
4906 ret
= ftrace_process_regex(iter
, parser
->buffer
,
4907 parser
->idx
, enable
);
4908 trace_parser_clear(parser
);
4919 ftrace_filter_write(struct file
*file
, const char __user
*ubuf
,
4920 size_t cnt
, loff_t
*ppos
)
4922 return ftrace_regex_write(file
, ubuf
, cnt
, ppos
, 1);
4926 ftrace_notrace_write(struct file
*file
, const char __user
*ubuf
,
4927 size_t cnt
, loff_t
*ppos
)
4929 return ftrace_regex_write(file
, ubuf
, cnt
, ppos
, 0);
4933 ftrace_match_addr(struct ftrace_hash
*hash
, unsigned long ip
, int remove
)
4935 struct ftrace_func_entry
*entry
;
4937 if (!ftrace_location(ip
))
4941 entry
= ftrace_lookup_ip(hash
, ip
);
4944 free_hash_entry(hash
, entry
);
4948 return add_hash_entry(hash
, ip
);
4952 ftrace_set_hash(struct ftrace_ops
*ops
, unsigned char *buf
, int len
,
4953 unsigned long ip
, int remove
, int reset
, int enable
)
4955 struct ftrace_hash
**orig_hash
;
4956 struct ftrace_hash
*hash
;
4959 if (unlikely(ftrace_disabled
))
4962 mutex_lock(&ops
->func_hash
->regex_lock
);
4965 orig_hash
= &ops
->func_hash
->filter_hash
;
4967 orig_hash
= &ops
->func_hash
->notrace_hash
;
4970 hash
= alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
);
4972 hash
= alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
, *orig_hash
);
4976 goto out_regex_unlock
;
4979 if (buf
&& !ftrace_match_records(hash
, buf
, len
)) {
4981 goto out_regex_unlock
;
4984 ret
= ftrace_match_addr(hash
, ip
, remove
);
4986 goto out_regex_unlock
;
4989 mutex_lock(&ftrace_lock
);
4990 ret
= ftrace_hash_move_and_update_ops(ops
, orig_hash
, hash
, enable
);
4991 mutex_unlock(&ftrace_lock
);
4994 mutex_unlock(&ops
->func_hash
->regex_lock
);
4996 free_ftrace_hash(hash
);
5001 ftrace_set_addr(struct ftrace_ops
*ops
, unsigned long ip
, int remove
,
5002 int reset
, int enable
)
5004 return ftrace_set_hash(ops
, NULL
, 0, ip
, remove
, reset
, enable
);
5007 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
5009 struct ftrace_direct_func
{
5010 struct list_head next
;
5015 static LIST_HEAD(ftrace_direct_funcs
);
5018 * ftrace_find_direct_func - test an address if it is a registered direct caller
5019 * @addr: The address of a registered direct caller
5021 * This searches to see if a ftrace direct caller has been registered
5022 * at a specific address, and if so, it returns a descriptor for it.
5024 * This can be used by architecture code to see if an address is
5025 * a direct caller (trampoline) attached to a fentry/mcount location.
5026 * This is useful for the function_graph tracer, as it may need to
5027 * do adjustments if it traced a location that also has a direct
5028 * trampoline attached to it.
5030 struct ftrace_direct_func
*ftrace_find_direct_func(unsigned long addr
)
5032 struct ftrace_direct_func
*entry
;
5035 /* May be called by fgraph trampoline (protected by rcu tasks) */
5036 list_for_each_entry_rcu(entry
, &ftrace_direct_funcs
, next
) {
5037 if (entry
->addr
== addr
) {
5048 static struct ftrace_direct_func
*ftrace_alloc_direct_func(unsigned long addr
)
5050 struct ftrace_direct_func
*direct
;
5052 direct
= kmalloc(sizeof(*direct
), GFP_KERNEL
);
5055 direct
->addr
= addr
;
5057 list_add_rcu(&direct
->next
, &ftrace_direct_funcs
);
5058 ftrace_direct_func_count
++;
5063 * register_ftrace_direct - Call a custom trampoline directly
5064 * @ip: The address of the nop at the beginning of a function
5065 * @addr: The address of the trampoline to call at @ip
5067 * This is used to connect a direct call from the nop location (@ip)
5068 * at the start of ftrace traced functions. The location that it calls
5069 * (@addr) must be able to handle a direct call, and save the parameters
5070 * of the function being traced, and restore them (or inject new ones
5071 * if needed), before returning.
5075 * -EBUSY - Another direct function is already attached (there can be only one)
5076 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
5077 * -ENOMEM - There was an allocation failure.
5079 int register_ftrace_direct(unsigned long ip
, unsigned long addr
)
5081 struct ftrace_direct_func
*direct
;
5082 struct ftrace_func_entry
*entry
;
5083 struct ftrace_hash
*free_hash
= NULL
;
5084 struct dyn_ftrace
*rec
;
5087 mutex_lock(&direct_mutex
);
5089 /* See if there's a direct function at @ip already */
5090 if (ftrace_find_rec_direct(ip
))
5094 rec
= lookup_rec(ip
, ip
);
5099 * Check if the rec says it has a direct call but we didn't
5102 if (WARN_ON(rec
->flags
& FTRACE_FL_DIRECT
))
5105 /* Make sure the ip points to the exact record */
5106 if (ip
!= rec
->ip
) {
5108 /* Need to check this ip for a direct. */
5109 if (ftrace_find_rec_direct(ip
))
5114 if (ftrace_hash_empty(direct_functions
) ||
5115 direct_functions
->count
> 2 * (1 << direct_functions
->size_bits
)) {
5116 struct ftrace_hash
*new_hash
;
5117 int size
= ftrace_hash_empty(direct_functions
) ? 0 :
5118 direct_functions
->count
+ 1;
5123 new_hash
= dup_hash(direct_functions
, size
);
5127 free_hash
= direct_functions
;
5128 direct_functions
= new_hash
;
5131 entry
= kmalloc(sizeof(*entry
), GFP_KERNEL
);
5135 direct
= ftrace_find_direct_func(addr
);
5137 direct
= ftrace_alloc_direct_func(addr
);
5145 entry
->direct
= addr
;
5146 __add_hash_entry(direct_functions
, entry
);
5148 ret
= ftrace_set_filter_ip(&direct_ops
, ip
, 0, 0);
5150 remove_hash_entry(direct_functions
, entry
);
5152 if (!ret
&& !(direct_ops
.flags
& FTRACE_OPS_FL_ENABLED
)) {
5153 ret
= register_ftrace_function(&direct_ops
);
5155 ftrace_set_filter_ip(&direct_ops
, ip
, 1, 0);
5160 if (!direct
->count
) {
5161 list_del_rcu(&direct
->next
);
5162 synchronize_rcu_tasks();
5165 free_ftrace_hash(free_hash
);
5167 ftrace_direct_func_count
--;
5173 mutex_unlock(&direct_mutex
);
5176 synchronize_rcu_tasks();
5177 free_ftrace_hash(free_hash
);
5182 EXPORT_SYMBOL_GPL(register_ftrace_direct
);
5184 static struct ftrace_func_entry
*find_direct_entry(unsigned long *ip
,
5185 struct dyn_ftrace
**recp
)
5187 struct ftrace_func_entry
*entry
;
5188 struct dyn_ftrace
*rec
;
5190 rec
= lookup_rec(*ip
, *ip
);
5194 entry
= __ftrace_lookup_ip(direct_functions
, rec
->ip
);
5196 WARN_ON(rec
->flags
& FTRACE_FL_DIRECT
);
5200 WARN_ON(!(rec
->flags
& FTRACE_FL_DIRECT
));
5202 /* Passed in ip just needs to be on the call site */
5211 int unregister_ftrace_direct(unsigned long ip
, unsigned long addr
)
5213 struct ftrace_direct_func
*direct
;
5214 struct ftrace_func_entry
*entry
;
5217 mutex_lock(&direct_mutex
);
5219 entry
= find_direct_entry(&ip
, NULL
);
5223 if (direct_functions
->count
== 1)
5224 unregister_ftrace_function(&direct_ops
);
5226 ret
= ftrace_set_filter_ip(&direct_ops
, ip
, 1, 0);
5230 remove_hash_entry(direct_functions
, entry
);
5232 direct
= ftrace_find_direct_func(addr
);
5233 if (!WARN_ON(!direct
)) {
5234 /* This is the good path (see the ! before WARN) */
5236 WARN_ON(direct
->count
< 0);
5237 if (!direct
->count
) {
5238 list_del_rcu(&direct
->next
);
5239 synchronize_rcu_tasks();
5242 ftrace_direct_func_count
--;
5246 mutex_unlock(&direct_mutex
);
5250 EXPORT_SYMBOL_GPL(unregister_ftrace_direct
);
5252 static struct ftrace_ops stub_ops
= {
5253 .func
= ftrace_stub
,
5257 * ftrace_modify_direct_caller - modify ftrace nop directly
5258 * @entry: The ftrace hash entry of the direct helper for @rec
5259 * @rec: The record representing the function site to patch
5260 * @old_addr: The location that the site at @rec->ip currently calls
5261 * @new_addr: The location that the site at @rec->ip should call
5263 * An architecture may overwrite this function to optimize the
5264 * changing of the direct callback on an ftrace nop location.
5265 * This is called with the ftrace_lock mutex held, and no other
5266 * ftrace callbacks are on the associated record (@rec). Thus,
5267 * it is safe to modify the ftrace record, where it should be
5268 * currently calling @old_addr directly, to call @new_addr.
5270 * Safety checks should be made to make sure that the code at
5271 * @rec->ip is currently calling @old_addr. And this must
5272 * also update entry->direct to @new_addr.
5274 int __weak
ftrace_modify_direct_caller(struct ftrace_func_entry
*entry
,
5275 struct dyn_ftrace
*rec
,
5276 unsigned long old_addr
,
5277 unsigned long new_addr
)
5279 unsigned long ip
= rec
->ip
;
5283 * The ftrace_lock was used to determine if the record
5284 * had more than one registered user to it. If it did,
5285 * we needed to prevent that from changing to do the quick
5286 * switch. But if it did not (only a direct caller was attached)
5287 * then this function is called. But this function can deal
5288 * with attached callers to the rec that we care about, and
5289 * since this function uses standard ftrace calls that take
5290 * the ftrace_lock mutex, we need to release it.
5292 mutex_unlock(&ftrace_lock
);
5295 * By setting a stub function at the same address, we force
5296 * the code to call the iterator and the direct_ops helper.
5297 * This means that @ip does not call the direct call, and
5298 * we can simply modify it.
5300 ret
= ftrace_set_filter_ip(&stub_ops
, ip
, 0, 0);
5304 ret
= register_ftrace_function(&stub_ops
);
5306 ftrace_set_filter_ip(&stub_ops
, ip
, 1, 0);
5310 entry
->direct
= new_addr
;
5313 * By removing the stub, we put back the direct call, calling
5316 unregister_ftrace_function(&stub_ops
);
5317 ftrace_set_filter_ip(&stub_ops
, ip
, 1, 0);
5320 mutex_lock(&ftrace_lock
);
5326 * modify_ftrace_direct - Modify an existing direct call to call something else
5327 * @ip: The instruction pointer to modify
5328 * @old_addr: The address that the current @ip calls directly
5329 * @new_addr: The address that the @ip should call
5331 * This modifies a ftrace direct caller at an instruction pointer without
5332 * having to disable it first. The direct call will switch over to the
5333 * @new_addr without missing anything.
5335 * Returns: zero on success. Non zero on error, which includes:
5336 * -ENODEV : the @ip given has no direct caller attached
5337 * -EINVAL : the @old_addr does not match the current direct caller
5339 int modify_ftrace_direct(unsigned long ip
,
5340 unsigned long old_addr
, unsigned long new_addr
)
5342 struct ftrace_direct_func
*direct
, *new_direct
= NULL
;
5343 struct ftrace_func_entry
*entry
;
5344 struct dyn_ftrace
*rec
;
5347 mutex_lock(&direct_mutex
);
5349 mutex_lock(&ftrace_lock
);
5350 entry
= find_direct_entry(&ip
, &rec
);
5355 if (entry
->direct
!= old_addr
)
5358 direct
= ftrace_find_direct_func(old_addr
);
5359 if (WARN_ON(!direct
))
5361 if (direct
->count
> 1) {
5363 new_direct
= ftrace_alloc_direct_func(new_addr
);
5367 new_direct
->count
++;
5369 direct
->addr
= new_addr
;
5373 * If there's no other ftrace callback on the rec->ip location,
5374 * then it can be changed directly by the architecture.
5375 * If there is another caller, then we just need to change the
5376 * direct caller helper to point to @new_addr.
5378 if (ftrace_rec_count(rec
) == 1) {
5379 ret
= ftrace_modify_direct_caller(entry
, rec
, old_addr
, new_addr
);
5381 entry
->direct
= new_addr
;
5385 if (unlikely(ret
&& new_direct
)) {
5387 list_del_rcu(&new_direct
->next
);
5388 synchronize_rcu_tasks();
5390 ftrace_direct_func_count
--;
5394 mutex_unlock(&ftrace_lock
);
5395 mutex_unlock(&direct_mutex
);
5398 EXPORT_SYMBOL_GPL(modify_ftrace_direct
);
5399 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
5402 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
5403 * @ops - the ops to set the filter with
5404 * @ip - the address to add to or remove from the filter.
5405 * @remove - non zero to remove the ip from the filter
5406 * @reset - non zero to reset all filters before applying this filter.
5408 * Filters denote which functions should be enabled when tracing is enabled
5409 * If @ip is NULL, it fails to update filter.
5411 int ftrace_set_filter_ip(struct ftrace_ops
*ops
, unsigned long ip
,
5412 int remove
, int reset
)
5414 ftrace_ops_init(ops
);
5415 return ftrace_set_addr(ops
, ip
, remove
, reset
, 1);
5417 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip
);
5420 * ftrace_ops_set_global_filter - setup ops to use global filters
5421 * @ops - the ops which will use the global filters
5423 * ftrace users who need global function trace filtering should call this.
5424 * It can set the global filter only if ops were not initialized before.
5426 void ftrace_ops_set_global_filter(struct ftrace_ops
*ops
)
5428 if (ops
->flags
& FTRACE_OPS_FL_INITIALIZED
)
5431 ftrace_ops_init(ops
);
5432 ops
->func_hash
= &global_ops
.local_hash
;
5434 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter
);
5437 ftrace_set_regex(struct ftrace_ops
*ops
, unsigned char *buf
, int len
,
5438 int reset
, int enable
)
5440 return ftrace_set_hash(ops
, buf
, len
, 0, 0, reset
, enable
);
5444 * ftrace_set_filter - set a function to filter on in ftrace
5445 * @ops - the ops to set the filter with
5446 * @buf - the string that holds the function filter text.
5447 * @len - the length of the string.
5448 * @reset - non zero to reset all filters before applying this filter.
5450 * Filters denote which functions should be enabled when tracing is enabled.
5451 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5453 int ftrace_set_filter(struct ftrace_ops
*ops
, unsigned char *buf
,
5456 ftrace_ops_init(ops
);
5457 return ftrace_set_regex(ops
, buf
, len
, reset
, 1);
5459 EXPORT_SYMBOL_GPL(ftrace_set_filter
);
5462 * ftrace_set_notrace - set a function to not trace in ftrace
5463 * @ops - the ops to set the notrace filter with
5464 * @buf - the string that holds the function notrace text.
5465 * @len - the length of the string.
5466 * @reset - non zero to reset all filters before applying this filter.
5468 * Notrace Filters denote which functions should not be enabled when tracing
5469 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5472 int ftrace_set_notrace(struct ftrace_ops
*ops
, unsigned char *buf
,
5475 ftrace_ops_init(ops
);
5476 return ftrace_set_regex(ops
, buf
, len
, reset
, 0);
5478 EXPORT_SYMBOL_GPL(ftrace_set_notrace
);
5480 * ftrace_set_global_filter - set a function to filter on with global tracers
5481 * @buf - the string that holds the function filter text.
5482 * @len - the length of the string.
5483 * @reset - non zero to reset all filters before applying this filter.
5485 * Filters denote which functions should be enabled when tracing is enabled.
5486 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5488 void ftrace_set_global_filter(unsigned char *buf
, int len
, int reset
)
5490 ftrace_set_regex(&global_ops
, buf
, len
, reset
, 1);
5492 EXPORT_SYMBOL_GPL(ftrace_set_global_filter
);
5495 * ftrace_set_global_notrace - set a function to not trace with global tracers
5496 * @buf - the string that holds the function notrace text.
5497 * @len - the length of the string.
5498 * @reset - non zero to reset all filters before applying this filter.
5500 * Notrace Filters denote which functions should not be enabled when tracing
5501 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5504 void ftrace_set_global_notrace(unsigned char *buf
, int len
, int reset
)
5506 ftrace_set_regex(&global_ops
, buf
, len
, reset
, 0);
5508 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace
);
5511 * command line interface to allow users to set filters on boot up.
5513 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
5514 static char ftrace_notrace_buf
[FTRACE_FILTER_SIZE
] __initdata
;
5515 static char ftrace_filter_buf
[FTRACE_FILTER_SIZE
] __initdata
;
5517 /* Used by function selftest to not test if filter is set */
5518 bool ftrace_filter_param __initdata
;
5520 static int __init
set_ftrace_notrace(char *str
)
5522 ftrace_filter_param
= true;
5523 strlcpy(ftrace_notrace_buf
, str
, FTRACE_FILTER_SIZE
);
5526 __setup("ftrace_notrace=", set_ftrace_notrace
);
5528 static int __init
set_ftrace_filter(char *str
)
5530 ftrace_filter_param
= true;
5531 strlcpy(ftrace_filter_buf
, str
, FTRACE_FILTER_SIZE
);
5534 __setup("ftrace_filter=", set_ftrace_filter
);
5536 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5537 static char ftrace_graph_buf
[FTRACE_FILTER_SIZE
] __initdata
;
5538 static char ftrace_graph_notrace_buf
[FTRACE_FILTER_SIZE
] __initdata
;
5539 static int ftrace_graph_set_hash(struct ftrace_hash
*hash
, char *buffer
);
5541 static int __init
set_graph_function(char *str
)
5543 strlcpy(ftrace_graph_buf
, str
, FTRACE_FILTER_SIZE
);
5546 __setup("ftrace_graph_filter=", set_graph_function
);
5548 static int __init
set_graph_notrace_function(char *str
)
5550 strlcpy(ftrace_graph_notrace_buf
, str
, FTRACE_FILTER_SIZE
);
5553 __setup("ftrace_graph_notrace=", set_graph_notrace_function
);
5555 static int __init
set_graph_max_depth_function(char *str
)
5559 fgraph_max_depth
= simple_strtoul(str
, NULL
, 0);
5562 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function
);
5564 static void __init
set_ftrace_early_graph(char *buf
, int enable
)
5568 struct ftrace_hash
*hash
;
5570 hash
= alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS
);
5571 if (MEM_FAIL(!hash
, "Failed to allocate hash\n"))
5575 func
= strsep(&buf
, ",");
5576 /* we allow only one expression at a time */
5577 ret
= ftrace_graph_set_hash(hash
, func
);
5579 printk(KERN_DEBUG
"ftrace: function %s not "
5580 "traceable\n", func
);
5584 ftrace_graph_hash
= hash
;
5586 ftrace_graph_notrace_hash
= hash
;
5588 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5591 ftrace_set_early_filter(struct ftrace_ops
*ops
, char *buf
, int enable
)
5595 ftrace_ops_init(ops
);
5598 func
= strsep(&buf
, ",");
5599 ftrace_set_regex(ops
, func
, strlen(func
), 0, enable
);
5603 static void __init
set_ftrace_early_filters(void)
5605 if (ftrace_filter_buf
[0])
5606 ftrace_set_early_filter(&global_ops
, ftrace_filter_buf
, 1);
5607 if (ftrace_notrace_buf
[0])
5608 ftrace_set_early_filter(&global_ops
, ftrace_notrace_buf
, 0);
5609 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5610 if (ftrace_graph_buf
[0])
5611 set_ftrace_early_graph(ftrace_graph_buf
, 1);
5612 if (ftrace_graph_notrace_buf
[0])
5613 set_ftrace_early_graph(ftrace_graph_notrace_buf
, 0);
5614 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5617 int ftrace_regex_release(struct inode
*inode
, struct file
*file
)
5619 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
5620 struct ftrace_iterator
*iter
;
5621 struct ftrace_hash
**orig_hash
;
5622 struct trace_parser
*parser
;
5625 if (file
->f_mode
& FMODE_READ
) {
5627 seq_release(inode
, file
);
5629 iter
= file
->private_data
;
5631 parser
= &iter
->parser
;
5632 if (trace_parser_loaded(parser
)) {
5633 int enable
= !(iter
->flags
& FTRACE_ITER_NOTRACE
);
5635 ftrace_process_regex(iter
, parser
->buffer
,
5636 parser
->idx
, enable
);
5639 trace_parser_put(parser
);
5641 mutex_lock(&iter
->ops
->func_hash
->regex_lock
);
5643 if (file
->f_mode
& FMODE_WRITE
) {
5644 filter_hash
= !!(iter
->flags
& FTRACE_ITER_FILTER
);
5647 orig_hash
= &iter
->ops
->func_hash
->filter_hash
;
5648 if (iter
->tr
&& !list_empty(&iter
->tr
->mod_trace
))
5649 iter
->hash
->flags
|= FTRACE_HASH_FL_MOD
;
5651 orig_hash
= &iter
->ops
->func_hash
->notrace_hash
;
5653 mutex_lock(&ftrace_lock
);
5654 ftrace_hash_move_and_update_ops(iter
->ops
, orig_hash
,
5655 iter
->hash
, filter_hash
);
5656 mutex_unlock(&ftrace_lock
);
5658 /* For read only, the hash is the ops hash */
5662 mutex_unlock(&iter
->ops
->func_hash
->regex_lock
);
5663 free_ftrace_hash(iter
->hash
);
5665 trace_array_put(iter
->tr
);
5671 static const struct file_operations ftrace_avail_fops
= {
5672 .open
= ftrace_avail_open
,
5674 .llseek
= seq_lseek
,
5675 .release
= seq_release_private
,
5678 static const struct file_operations ftrace_enabled_fops
= {
5679 .open
= ftrace_enabled_open
,
5681 .llseek
= seq_lseek
,
5682 .release
= seq_release_private
,
5685 static const struct file_operations ftrace_filter_fops
= {
5686 .open
= ftrace_filter_open
,
5688 .write
= ftrace_filter_write
,
5689 .llseek
= tracing_lseek
,
5690 .release
= ftrace_regex_release
,
5693 static const struct file_operations ftrace_notrace_fops
= {
5694 .open
= ftrace_notrace_open
,
5696 .write
= ftrace_notrace_write
,
5697 .llseek
= tracing_lseek
,
5698 .release
= ftrace_regex_release
,
5701 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5703 static DEFINE_MUTEX(graph_lock
);
5705 struct ftrace_hash __rcu
*ftrace_graph_hash
= EMPTY_HASH
;
5706 struct ftrace_hash __rcu
*ftrace_graph_notrace_hash
= EMPTY_HASH
;
5708 enum graph_filter_type
{
5709 GRAPH_FILTER_NOTRACE
= 0,
5710 GRAPH_FILTER_FUNCTION
,
5713 #define FTRACE_GRAPH_EMPTY ((void *)1)
5715 struct ftrace_graph_data
{
5716 struct ftrace_hash
*hash
;
5717 struct ftrace_func_entry
*entry
;
5718 int idx
; /* for hash table iteration */
5719 enum graph_filter_type type
;
5720 struct ftrace_hash
*new_hash
;
5721 const struct seq_operations
*seq_ops
;
5722 struct trace_parser parser
;
5726 __g_next(struct seq_file
*m
, loff_t
*pos
)
5728 struct ftrace_graph_data
*fgd
= m
->private;
5729 struct ftrace_func_entry
*entry
= fgd
->entry
;
5730 struct hlist_head
*head
;
5731 int i
, idx
= fgd
->idx
;
5733 if (*pos
>= fgd
->hash
->count
)
5737 hlist_for_each_entry_continue(entry
, hlist
) {
5745 for (i
= idx
; i
< 1 << fgd
->hash
->size_bits
; i
++) {
5746 head
= &fgd
->hash
->buckets
[i
];
5747 hlist_for_each_entry(entry
, head
, hlist
) {
5757 g_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
5760 return __g_next(m
, pos
);
5763 static void *g_start(struct seq_file
*m
, loff_t
*pos
)
5765 struct ftrace_graph_data
*fgd
= m
->private;
5767 mutex_lock(&graph_lock
);
5769 if (fgd
->type
== GRAPH_FILTER_FUNCTION
)
5770 fgd
->hash
= rcu_dereference_protected(ftrace_graph_hash
,
5771 lockdep_is_held(&graph_lock
));
5773 fgd
->hash
= rcu_dereference_protected(ftrace_graph_notrace_hash
,
5774 lockdep_is_held(&graph_lock
));
5776 /* Nothing, tell g_show to print all functions are enabled */
5777 if (ftrace_hash_empty(fgd
->hash
) && !*pos
)
5778 return FTRACE_GRAPH_EMPTY
;
5782 return __g_next(m
, pos
);
5785 static void g_stop(struct seq_file
*m
, void *p
)
5787 mutex_unlock(&graph_lock
);
5790 static int g_show(struct seq_file
*m
, void *v
)
5792 struct ftrace_func_entry
*entry
= v
;
5797 if (entry
== FTRACE_GRAPH_EMPTY
) {
5798 struct ftrace_graph_data
*fgd
= m
->private;
5800 if (fgd
->type
== GRAPH_FILTER_FUNCTION
)
5801 seq_puts(m
, "#### all functions enabled ####\n");
5803 seq_puts(m
, "#### no functions disabled ####\n");
5807 seq_printf(m
, "%ps\n", (void *)entry
->ip
);
5812 static const struct seq_operations ftrace_graph_seq_ops
= {
5820 __ftrace_graph_open(struct inode
*inode
, struct file
*file
,
5821 struct ftrace_graph_data
*fgd
)
5824 struct ftrace_hash
*new_hash
= NULL
;
5826 ret
= security_locked_down(LOCKDOWN_TRACEFS
);
5830 if (file
->f_mode
& FMODE_WRITE
) {
5831 const int size_bits
= FTRACE_HASH_DEFAULT_BITS
;
5833 if (trace_parser_get_init(&fgd
->parser
, FTRACE_BUFF_MAX
))
5836 if (file
->f_flags
& O_TRUNC
)
5837 new_hash
= alloc_ftrace_hash(size_bits
);
5839 new_hash
= alloc_and_copy_ftrace_hash(size_bits
,
5847 if (file
->f_mode
& FMODE_READ
) {
5848 ret
= seq_open(file
, &ftrace_graph_seq_ops
);
5850 struct seq_file
*m
= file
->private_data
;
5854 free_ftrace_hash(new_hash
);
5858 file
->private_data
= fgd
;
5861 if (ret
< 0 && file
->f_mode
& FMODE_WRITE
)
5862 trace_parser_put(&fgd
->parser
);
5864 fgd
->new_hash
= new_hash
;
5867 * All uses of fgd->hash must be taken with the graph_lock
5868 * held. The graph_lock is going to be released, so force
5869 * fgd->hash to be reinitialized when it is taken again.
5877 ftrace_graph_open(struct inode
*inode
, struct file
*file
)
5879 struct ftrace_graph_data
*fgd
;
5882 if (unlikely(ftrace_disabled
))
5885 fgd
= kmalloc(sizeof(*fgd
), GFP_KERNEL
);
5889 mutex_lock(&graph_lock
);
5891 fgd
->hash
= rcu_dereference_protected(ftrace_graph_hash
,
5892 lockdep_is_held(&graph_lock
));
5893 fgd
->type
= GRAPH_FILTER_FUNCTION
;
5894 fgd
->seq_ops
= &ftrace_graph_seq_ops
;
5896 ret
= __ftrace_graph_open(inode
, file
, fgd
);
5900 mutex_unlock(&graph_lock
);
5905 ftrace_graph_notrace_open(struct inode
*inode
, struct file
*file
)
5907 struct ftrace_graph_data
*fgd
;
5910 if (unlikely(ftrace_disabled
))
5913 fgd
= kmalloc(sizeof(*fgd
), GFP_KERNEL
);
5917 mutex_lock(&graph_lock
);
5919 fgd
->hash
= rcu_dereference_protected(ftrace_graph_notrace_hash
,
5920 lockdep_is_held(&graph_lock
));
5921 fgd
->type
= GRAPH_FILTER_NOTRACE
;
5922 fgd
->seq_ops
= &ftrace_graph_seq_ops
;
5924 ret
= __ftrace_graph_open(inode
, file
, fgd
);
5928 mutex_unlock(&graph_lock
);
5933 ftrace_graph_release(struct inode
*inode
, struct file
*file
)
5935 struct ftrace_graph_data
*fgd
;
5936 struct ftrace_hash
*old_hash
, *new_hash
;
5937 struct trace_parser
*parser
;
5940 if (file
->f_mode
& FMODE_READ
) {
5941 struct seq_file
*m
= file
->private_data
;
5944 seq_release(inode
, file
);
5946 fgd
= file
->private_data
;
5950 if (file
->f_mode
& FMODE_WRITE
) {
5952 parser
= &fgd
->parser
;
5954 if (trace_parser_loaded((parser
))) {
5955 ret
= ftrace_graph_set_hash(fgd
->new_hash
,
5959 trace_parser_put(parser
);
5961 new_hash
= __ftrace_hash_move(fgd
->new_hash
);
5967 mutex_lock(&graph_lock
);
5969 if (fgd
->type
== GRAPH_FILTER_FUNCTION
) {
5970 old_hash
= rcu_dereference_protected(ftrace_graph_hash
,
5971 lockdep_is_held(&graph_lock
));
5972 rcu_assign_pointer(ftrace_graph_hash
, new_hash
);
5974 old_hash
= rcu_dereference_protected(ftrace_graph_notrace_hash
,
5975 lockdep_is_held(&graph_lock
));
5976 rcu_assign_pointer(ftrace_graph_notrace_hash
, new_hash
);
5979 mutex_unlock(&graph_lock
);
5982 * We need to do a hard force of sched synchronization.
5983 * This is because we use preempt_disable() to do RCU, but
5984 * the function tracers can be called where RCU is not watching
5985 * (like before user_exit()). We can not rely on the RCU
5986 * infrastructure to do the synchronization, thus we must do it
5989 if (old_hash
!= EMPTY_HASH
)
5990 synchronize_rcu_tasks_rude();
5992 free_ftrace_hash(old_hash
);
5996 free_ftrace_hash(fgd
->new_hash
);
6003 ftrace_graph_set_hash(struct ftrace_hash
*hash
, char *buffer
)
6005 struct ftrace_glob func_g
;
6006 struct dyn_ftrace
*rec
;
6007 struct ftrace_page
*pg
;
6008 struct ftrace_func_entry
*entry
;
6013 func_g
.type
= filter_parse_regex(buffer
, strlen(buffer
),
6014 &func_g
.search
, ¬);
6016 func_g
.len
= strlen(func_g
.search
);
6018 mutex_lock(&ftrace_lock
);
6020 if (unlikely(ftrace_disabled
)) {
6021 mutex_unlock(&ftrace_lock
);
6025 do_for_each_ftrace_rec(pg
, rec
) {
6027 if (rec
->flags
& FTRACE_FL_DISABLED
)
6030 if (ftrace_match_record(rec
, &func_g
, NULL
, 0)) {
6031 entry
= ftrace_lookup_ip(hash
, rec
->ip
);
6038 if (add_hash_entry(hash
, rec
->ip
) < 0)
6042 free_hash_entry(hash
, entry
);
6047 } while_for_each_ftrace_rec();
6049 mutex_unlock(&ftrace_lock
);
6058 ftrace_graph_write(struct file
*file
, const char __user
*ubuf
,
6059 size_t cnt
, loff_t
*ppos
)
6061 ssize_t read
, ret
= 0;
6062 struct ftrace_graph_data
*fgd
= file
->private_data
;
6063 struct trace_parser
*parser
;
6068 /* Read mode uses seq functions */
6069 if (file
->f_mode
& FMODE_READ
) {
6070 struct seq_file
*m
= file
->private_data
;
6074 parser
= &fgd
->parser
;
6076 read
= trace_get_user(parser
, ubuf
, cnt
, ppos
);
6078 if (read
>= 0 && trace_parser_loaded(parser
) &&
6079 !trace_parser_cont(parser
)) {
6081 ret
= ftrace_graph_set_hash(fgd
->new_hash
,
6083 trace_parser_clear(parser
);
6092 static const struct file_operations ftrace_graph_fops
= {
6093 .open
= ftrace_graph_open
,
6095 .write
= ftrace_graph_write
,
6096 .llseek
= tracing_lseek
,
6097 .release
= ftrace_graph_release
,
6100 static const struct file_operations ftrace_graph_notrace_fops
= {
6101 .open
= ftrace_graph_notrace_open
,
6103 .write
= ftrace_graph_write
,
6104 .llseek
= tracing_lseek
,
6105 .release
= ftrace_graph_release
,
6107 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6109 void ftrace_create_filter_files(struct ftrace_ops
*ops
,
6110 struct dentry
*parent
)
6113 trace_create_file("set_ftrace_filter", TRACE_MODE_WRITE
, parent
,
6114 ops
, &ftrace_filter_fops
);
6116 trace_create_file("set_ftrace_notrace", TRACE_MODE_WRITE
, parent
,
6117 ops
, &ftrace_notrace_fops
);
6121 * The name "destroy_filter_files" is really a misnomer. Although
6122 * in the future, it may actually delete the files, but this is
6123 * really intended to make sure the ops passed in are disabled
6124 * and that when this function returns, the caller is free to
6127 * The "destroy" name is only to match the "create" name that this
6128 * should be paired with.
6130 void ftrace_destroy_filter_files(struct ftrace_ops
*ops
)
6132 mutex_lock(&ftrace_lock
);
6133 if (ops
->flags
& FTRACE_OPS_FL_ENABLED
)
6134 ftrace_shutdown(ops
, 0);
6135 ops
->flags
|= FTRACE_OPS_FL_DELETED
;
6136 ftrace_free_filter(ops
);
6137 mutex_unlock(&ftrace_lock
);
6140 static __init
int ftrace_init_dyn_tracefs(struct dentry
*d_tracer
)
6143 trace_create_file("available_filter_functions", TRACE_MODE_READ
,
6144 d_tracer
, NULL
, &ftrace_avail_fops
);
6146 trace_create_file("enabled_functions", TRACE_MODE_READ
,
6147 d_tracer
, NULL
, &ftrace_enabled_fops
);
6149 ftrace_create_filter_files(&global_ops
, d_tracer
);
6151 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
6152 trace_create_file("set_graph_function", TRACE_MODE_WRITE
, d_tracer
,
6154 &ftrace_graph_fops
);
6155 trace_create_file("set_graph_notrace", TRACE_MODE_WRITE
, d_tracer
,
6157 &ftrace_graph_notrace_fops
);
6158 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6163 static int ftrace_cmp_ips(const void *a
, const void *b
)
6165 const unsigned long *ipa
= a
;
6166 const unsigned long *ipb
= b
;
6175 static int ftrace_process_locs(struct module
*mod
,
6176 unsigned long *start
,
6179 struct ftrace_page
*start_pg
;
6180 struct ftrace_page
*pg
;
6181 struct dyn_ftrace
*rec
;
6182 unsigned long count
;
6185 unsigned long flags
= 0; /* Shut up gcc */
6188 count
= end
- start
;
6193 sort(start
, count
, sizeof(*start
),
6194 ftrace_cmp_ips
, NULL
);
6196 start_pg
= ftrace_allocate_pages(count
);
6200 mutex_lock(&ftrace_lock
);
6203 * Core and each module needs their own pages, as
6204 * modules will free them when they are removed.
6205 * Force a new page to be allocated for modules.
6208 WARN_ON(ftrace_pages
|| ftrace_pages_start
);
6209 /* First initialization */
6210 ftrace_pages
= ftrace_pages_start
= start_pg
;
6215 if (WARN_ON(ftrace_pages
->next
)) {
6216 /* Hmm, we have free pages? */
6217 while (ftrace_pages
->next
)
6218 ftrace_pages
= ftrace_pages
->next
;
6221 ftrace_pages
->next
= start_pg
;
6227 unsigned long end_offset
;
6228 addr
= ftrace_call_adjust(*p
++);
6230 * Some architecture linkers will pad between
6231 * the different mcount_loc sections of different
6232 * object files to satisfy alignments.
6233 * Skip any NULL pointers.
6238 end_offset
= (pg
->index
+1) * sizeof(pg
->records
[0]);
6239 if (end_offset
> PAGE_SIZE
<< pg
->order
) {
6240 /* We should have allocated enough */
6241 if (WARN_ON(!pg
->next
))
6246 rec
= &pg
->records
[pg
->index
++];
6250 /* We should have used all pages */
6253 /* Assign the last page to ftrace_pages */
6257 * We only need to disable interrupts on start up
6258 * because we are modifying code that an interrupt
6259 * may execute, and the modification is not atomic.
6260 * But for modules, nothing runs the code we modify
6261 * until we are finished with it, and there's no
6262 * reason to cause large interrupt latencies while we do it.
6265 local_irq_save(flags
);
6266 ftrace_update_code(mod
, start_pg
);
6268 local_irq_restore(flags
);
6271 mutex_unlock(&ftrace_lock
);
6276 struct ftrace_mod_func
{
6277 struct list_head list
;
6283 struct ftrace_mod_map
{
6284 struct rcu_head rcu
;
6285 struct list_head list
;
6287 unsigned long start_addr
;
6288 unsigned long end_addr
;
6289 struct list_head funcs
;
6290 unsigned int num_funcs
;
6293 static int ftrace_get_trampoline_kallsym(unsigned int symnum
,
6294 unsigned long *value
, char *type
,
6295 char *name
, char *module_name
,
6298 struct ftrace_ops
*op
;
6300 list_for_each_entry_rcu(op
, &ftrace_ops_trampoline_list
, list
) {
6301 if (!op
->trampoline
|| symnum
--)
6303 *value
= op
->trampoline
;
6305 strlcpy(name
, FTRACE_TRAMPOLINE_SYM
, KSYM_NAME_LEN
);
6306 strlcpy(module_name
, FTRACE_TRAMPOLINE_MOD
, MODULE_NAME_LEN
);
6314 #ifdef CONFIG_MODULES
6316 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
6318 static LIST_HEAD(ftrace_mod_maps
);
6320 static int referenced_filters(struct dyn_ftrace
*rec
)
6322 struct ftrace_ops
*ops
;
6325 for (ops
= ftrace_ops_list
; ops
!= &ftrace_list_end
; ops
= ops
->next
) {
6326 if (ops_references_rec(ops
, rec
)) {
6327 if (WARN_ON_ONCE(ops
->flags
& FTRACE_OPS_FL_DIRECT
))
6329 if (WARN_ON_ONCE(ops
->flags
& FTRACE_OPS_FL_IPMODIFY
))
6332 if (ops
->flags
& FTRACE_OPS_FL_SAVE_REGS
)
6333 rec
->flags
|= FTRACE_FL_REGS
;
6334 if (cnt
== 1 && ops
->trampoline
)
6335 rec
->flags
|= FTRACE_FL_TRAMP
;
6337 rec
->flags
&= ~FTRACE_FL_TRAMP
;
6345 clear_mod_from_hash(struct ftrace_page
*pg
, struct ftrace_hash
*hash
)
6347 struct ftrace_func_entry
*entry
;
6348 struct dyn_ftrace
*rec
;
6351 if (ftrace_hash_empty(hash
))
6354 for (i
= 0; i
< pg
->index
; i
++) {
6355 rec
= &pg
->records
[i
];
6356 entry
= __ftrace_lookup_ip(hash
, rec
->ip
);
6358 * Do not allow this rec to match again.
6359 * Yeah, it may waste some memory, but will be removed
6360 * if/when the hash is modified again.
6367 /* Clear any records from hashes */
6368 static void clear_mod_from_hashes(struct ftrace_page
*pg
)
6370 struct trace_array
*tr
;
6372 mutex_lock(&trace_types_lock
);
6373 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
6374 if (!tr
->ops
|| !tr
->ops
->func_hash
)
6376 mutex_lock(&tr
->ops
->func_hash
->regex_lock
);
6377 clear_mod_from_hash(pg
, tr
->ops
->func_hash
->filter_hash
);
6378 clear_mod_from_hash(pg
, tr
->ops
->func_hash
->notrace_hash
);
6379 mutex_unlock(&tr
->ops
->func_hash
->regex_lock
);
6381 mutex_unlock(&trace_types_lock
);
6384 static void ftrace_free_mod_map(struct rcu_head
*rcu
)
6386 struct ftrace_mod_map
*mod_map
= container_of(rcu
, struct ftrace_mod_map
, rcu
);
6387 struct ftrace_mod_func
*mod_func
;
6388 struct ftrace_mod_func
*n
;
6390 /* All the contents of mod_map are now not visible to readers */
6391 list_for_each_entry_safe(mod_func
, n
, &mod_map
->funcs
, list
) {
6392 kfree(mod_func
->name
);
6393 list_del(&mod_func
->list
);
6400 void ftrace_release_mod(struct module
*mod
)
6402 struct ftrace_mod_map
*mod_map
;
6403 struct ftrace_mod_map
*n
;
6404 struct dyn_ftrace
*rec
;
6405 struct ftrace_page
**last_pg
;
6406 struct ftrace_page
*tmp_page
= NULL
;
6407 struct ftrace_page
*pg
;
6409 mutex_lock(&ftrace_lock
);
6411 if (ftrace_disabled
)
6414 list_for_each_entry_safe(mod_map
, n
, &ftrace_mod_maps
, list
) {
6415 if (mod_map
->mod
== mod
) {
6416 list_del_rcu(&mod_map
->list
);
6417 call_rcu(&mod_map
->rcu
, ftrace_free_mod_map
);
6423 * Each module has its own ftrace_pages, remove
6424 * them from the list.
6426 last_pg
= &ftrace_pages_start
;
6427 for (pg
= ftrace_pages_start
; pg
; pg
= *last_pg
) {
6428 rec
= &pg
->records
[0];
6429 if (within_module_core(rec
->ip
, mod
) ||
6430 within_module_init(rec
->ip
, mod
)) {
6432 * As core pages are first, the first
6433 * page should never be a module page.
6435 if (WARN_ON(pg
== ftrace_pages_start
))
6438 /* Check if we are deleting the last page */
6439 if (pg
== ftrace_pages
)
6440 ftrace_pages
= next_to_ftrace_page(last_pg
);
6442 ftrace_update_tot_cnt
-= pg
->index
;
6443 *last_pg
= pg
->next
;
6445 pg
->next
= tmp_page
;
6448 last_pg
= &pg
->next
;
6451 mutex_unlock(&ftrace_lock
);
6453 for (pg
= tmp_page
; pg
; pg
= tmp_page
) {
6455 /* Needs to be called outside of ftrace_lock */
6456 clear_mod_from_hashes(pg
);
6459 free_pages((unsigned long)pg
->records
, pg
->order
);
6460 ftrace_number_of_pages
-= 1 << pg
->order
;
6462 tmp_page
= pg
->next
;
6464 ftrace_number_of_groups
--;
6468 void ftrace_module_enable(struct module
*mod
)
6470 struct dyn_ftrace
*rec
;
6471 struct ftrace_page
*pg
;
6473 mutex_lock(&ftrace_lock
);
6475 if (ftrace_disabled
)
6479 * If the tracing is enabled, go ahead and enable the record.
6481 * The reason not to enable the record immediately is the
6482 * inherent check of ftrace_make_nop/ftrace_make_call for
6483 * correct previous instructions. Making first the NOP
6484 * conversion puts the module to the correct state, thus
6485 * passing the ftrace_make_call check.
6487 * We also delay this to after the module code already set the
6488 * text to read-only, as we now need to set it back to read-write
6489 * so that we can modify the text.
6491 if (ftrace_start_up
)
6492 ftrace_arch_code_modify_prepare();
6494 do_for_each_ftrace_rec(pg
, rec
) {
6497 * do_for_each_ftrace_rec() is a double loop.
6498 * module text shares the pg. If a record is
6499 * not part of this module, then skip this pg,
6500 * which the "break" will do.
6502 if (!within_module_core(rec
->ip
, mod
) &&
6503 !within_module_init(rec
->ip
, mod
))
6509 * When adding a module, we need to check if tracers are
6510 * currently enabled and if they are, and can trace this record,
6511 * we need to enable the module functions as well as update the
6512 * reference counts for those function records.
6514 if (ftrace_start_up
)
6515 cnt
+= referenced_filters(rec
);
6517 rec
->flags
&= ~FTRACE_FL_DISABLED
;
6520 if (ftrace_start_up
&& cnt
) {
6521 int failed
= __ftrace_replace_code(rec
, 1);
6523 ftrace_bug(failed
, rec
);
6528 } while_for_each_ftrace_rec();
6531 if (ftrace_start_up
)
6532 ftrace_arch_code_modify_post_process();
6535 mutex_unlock(&ftrace_lock
);
6537 process_cached_mods(mod
->name
);
6540 void ftrace_module_init(struct module
*mod
)
6542 if (ftrace_disabled
|| !mod
->num_ftrace_callsites
)
6545 ftrace_process_locs(mod
, mod
->ftrace_callsites
,
6546 mod
->ftrace_callsites
+ mod
->num_ftrace_callsites
);
6549 static void save_ftrace_mod_rec(struct ftrace_mod_map
*mod_map
,
6550 struct dyn_ftrace
*rec
)
6552 struct ftrace_mod_func
*mod_func
;
6553 unsigned long symsize
;
6554 unsigned long offset
;
6555 char str
[KSYM_SYMBOL_LEN
];
6559 ret
= kallsyms_lookup(rec
->ip
, &symsize
, &offset
, &modname
, str
);
6563 mod_func
= kmalloc(sizeof(*mod_func
), GFP_KERNEL
);
6567 mod_func
->name
= kstrdup(str
, GFP_KERNEL
);
6568 if (!mod_func
->name
) {
6573 mod_func
->ip
= rec
->ip
- offset
;
6574 mod_func
->size
= symsize
;
6576 mod_map
->num_funcs
++;
6578 list_add_rcu(&mod_func
->list
, &mod_map
->funcs
);
6581 static struct ftrace_mod_map
*
6582 allocate_ftrace_mod_map(struct module
*mod
,
6583 unsigned long start
, unsigned long end
)
6585 struct ftrace_mod_map
*mod_map
;
6587 mod_map
= kmalloc(sizeof(*mod_map
), GFP_KERNEL
);
6592 mod_map
->start_addr
= start
;
6593 mod_map
->end_addr
= end
;
6594 mod_map
->num_funcs
= 0;
6596 INIT_LIST_HEAD_RCU(&mod_map
->funcs
);
6598 list_add_rcu(&mod_map
->list
, &ftrace_mod_maps
);
6604 ftrace_func_address_lookup(struct ftrace_mod_map
*mod_map
,
6605 unsigned long addr
, unsigned long *size
,
6606 unsigned long *off
, char *sym
)
6608 struct ftrace_mod_func
*found_func
= NULL
;
6609 struct ftrace_mod_func
*mod_func
;
6611 list_for_each_entry_rcu(mod_func
, &mod_map
->funcs
, list
) {
6612 if (addr
>= mod_func
->ip
&&
6613 addr
< mod_func
->ip
+ mod_func
->size
) {
6614 found_func
= mod_func
;
6621 *size
= found_func
->size
;
6623 *off
= addr
- found_func
->ip
;
6625 strlcpy(sym
, found_func
->name
, KSYM_NAME_LEN
);
6627 return found_func
->name
;
6634 ftrace_mod_address_lookup(unsigned long addr
, unsigned long *size
,
6635 unsigned long *off
, char **modname
, char *sym
)
6637 struct ftrace_mod_map
*mod_map
;
6638 const char *ret
= NULL
;
6640 /* mod_map is freed via call_rcu() */
6642 list_for_each_entry_rcu(mod_map
, &ftrace_mod_maps
, list
) {
6643 ret
= ftrace_func_address_lookup(mod_map
, addr
, size
, off
, sym
);
6646 *modname
= mod_map
->mod
->name
;
6655 int ftrace_mod_get_kallsym(unsigned int symnum
, unsigned long *value
,
6656 char *type
, char *name
,
6657 char *module_name
, int *exported
)
6659 struct ftrace_mod_map
*mod_map
;
6660 struct ftrace_mod_func
*mod_func
;
6664 list_for_each_entry_rcu(mod_map
, &ftrace_mod_maps
, list
) {
6666 if (symnum
>= mod_map
->num_funcs
) {
6667 symnum
-= mod_map
->num_funcs
;
6671 list_for_each_entry_rcu(mod_func
, &mod_map
->funcs
, list
) {
6677 *value
= mod_func
->ip
;
6679 strlcpy(name
, mod_func
->name
, KSYM_NAME_LEN
);
6680 strlcpy(module_name
, mod_map
->mod
->name
, MODULE_NAME_LEN
);
6688 ret
= ftrace_get_trampoline_kallsym(symnum
, value
, type
, name
,
6689 module_name
, exported
);
6695 static void save_ftrace_mod_rec(struct ftrace_mod_map
*mod_map
,
6696 struct dyn_ftrace
*rec
) { }
6697 static inline struct ftrace_mod_map
*
6698 allocate_ftrace_mod_map(struct module
*mod
,
6699 unsigned long start
, unsigned long end
)
6703 int ftrace_mod_get_kallsym(unsigned int symnum
, unsigned long *value
,
6704 char *type
, char *name
, char *module_name
,
6710 ret
= ftrace_get_trampoline_kallsym(symnum
, value
, type
, name
,
6711 module_name
, exported
);
6715 #endif /* CONFIG_MODULES */
6717 struct ftrace_init_func
{
6718 struct list_head list
;
6722 /* Clear any init ips from hashes */
6724 clear_func_from_hash(struct ftrace_init_func
*func
, struct ftrace_hash
*hash
)
6726 struct ftrace_func_entry
*entry
;
6728 entry
= ftrace_lookup_ip(hash
, func
->ip
);
6730 * Do not allow this rec to match again.
6731 * Yeah, it may waste some memory, but will be removed
6732 * if/when the hash is modified again.
6739 clear_func_from_hashes(struct ftrace_init_func
*func
)
6741 struct trace_array
*tr
;
6743 mutex_lock(&trace_types_lock
);
6744 list_for_each_entry(tr
, &ftrace_trace_arrays
, list
) {
6745 if (!tr
->ops
|| !tr
->ops
->func_hash
)
6747 mutex_lock(&tr
->ops
->func_hash
->regex_lock
);
6748 clear_func_from_hash(func
, tr
->ops
->func_hash
->filter_hash
);
6749 clear_func_from_hash(func
, tr
->ops
->func_hash
->notrace_hash
);
6750 mutex_unlock(&tr
->ops
->func_hash
->regex_lock
);
6752 mutex_unlock(&trace_types_lock
);
6755 static void add_to_clear_hash_list(struct list_head
*clear_list
,
6756 struct dyn_ftrace
*rec
)
6758 struct ftrace_init_func
*func
;
6760 func
= kmalloc(sizeof(*func
), GFP_KERNEL
);
6762 MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
6767 list_add(&func
->list
, clear_list
);
6770 void ftrace_free_mem(struct module
*mod
, void *start_ptr
, void *end_ptr
)
6772 unsigned long start
= (unsigned long)(start_ptr
);
6773 unsigned long end
= (unsigned long)(end_ptr
);
6774 struct ftrace_page
**last_pg
= &ftrace_pages_start
;
6775 struct ftrace_page
*pg
;
6776 struct dyn_ftrace
*rec
;
6777 struct dyn_ftrace key
;
6778 struct ftrace_mod_map
*mod_map
= NULL
;
6779 struct ftrace_init_func
*func
, *func_next
;
6780 struct list_head clear_hash
;
6782 INIT_LIST_HEAD(&clear_hash
);
6785 key
.flags
= end
; /* overload flags, as it is unsigned long */
6787 mutex_lock(&ftrace_lock
);
6790 * If we are freeing module init memory, then check if
6791 * any tracer is active. If so, we need to save a mapping of
6792 * the module functions being freed with the address.
6794 if (mod
&& ftrace_ops_list
!= &ftrace_list_end
)
6795 mod_map
= allocate_ftrace_mod_map(mod
, start
, end
);
6797 for (pg
= ftrace_pages_start
; pg
; last_pg
= &pg
->next
, pg
= *last_pg
) {
6798 if (end
< pg
->records
[0].ip
||
6799 start
>= (pg
->records
[pg
->index
- 1].ip
+ MCOUNT_INSN_SIZE
))
6802 rec
= bsearch(&key
, pg
->records
, pg
->index
,
6803 sizeof(struct dyn_ftrace
),
6808 /* rec will be cleared from hashes after ftrace_lock unlock */
6809 add_to_clear_hash_list(&clear_hash
, rec
);
6812 save_ftrace_mod_rec(mod_map
, rec
);
6815 ftrace_update_tot_cnt
--;
6817 *last_pg
= pg
->next
;
6819 free_pages((unsigned long)pg
->records
, pg
->order
);
6820 ftrace_number_of_pages
-= 1 << pg
->order
;
6822 ftrace_number_of_groups
--;
6824 pg
= container_of(last_pg
, struct ftrace_page
, next
);
6829 memmove(rec
, rec
+ 1,
6830 (pg
->index
- (rec
- pg
->records
)) * sizeof(*rec
));
6831 /* More than one function may be in this block */
6834 mutex_unlock(&ftrace_lock
);
6836 list_for_each_entry_safe(func
, func_next
, &clear_hash
, list
) {
6837 clear_func_from_hashes(func
);
6842 void __init
ftrace_free_init_mem(void)
6844 void *start
= (void *)(&__init_begin
);
6845 void *end
= (void *)(&__init_end
);
6847 ftrace_free_mem(NULL
, start
, end
);
6850 void __init
ftrace_init(void)
6852 extern unsigned long __start_mcount_loc
[];
6853 extern unsigned long __stop_mcount_loc
[];
6854 unsigned long count
, flags
;
6857 local_irq_save(flags
);
6858 ret
= ftrace_dyn_arch_init();
6859 local_irq_restore(flags
);
6863 count
= __stop_mcount_loc
- __start_mcount_loc
;
6865 pr_info("ftrace: No functions to be traced?\n");
6869 pr_info("ftrace: allocating %ld entries in %ld pages\n",
6870 count
, count
/ ENTRIES_PER_PAGE
+ 1);
6872 last_ftrace_enabled
= ftrace_enabled
= 1;
6874 ret
= ftrace_process_locs(NULL
,
6878 pr_info("ftrace: allocated %ld pages with %ld groups\n",
6879 ftrace_number_of_pages
, ftrace_number_of_groups
);
6881 set_ftrace_early_filters();
6885 ftrace_disabled
= 1;
6888 /* Do nothing if arch does not support this */
6889 void __weak
arch_ftrace_update_trampoline(struct ftrace_ops
*ops
)
6893 static void ftrace_update_trampoline(struct ftrace_ops
*ops
)
6895 unsigned long trampoline
= ops
->trampoline
;
6897 arch_ftrace_update_trampoline(ops
);
6898 if (ops
->trampoline
&& ops
->trampoline
!= trampoline
&&
6899 (ops
->flags
& FTRACE_OPS_FL_ALLOC_TRAMP
)) {
6900 /* Add to kallsyms before the perf events */
6901 ftrace_add_trampoline_to_kallsyms(ops
);
6902 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL
,
6903 ops
->trampoline
, ops
->trampoline_size
, false,
6904 FTRACE_TRAMPOLINE_SYM
);
6906 * Record the perf text poke event after the ksymbol register
6909 perf_event_text_poke((void *)ops
->trampoline
, NULL
, 0,
6910 (void *)ops
->trampoline
,
6911 ops
->trampoline_size
);
6915 void ftrace_init_trace_array(struct trace_array
*tr
)
6917 INIT_LIST_HEAD(&tr
->func_probes
);
6918 INIT_LIST_HEAD(&tr
->mod_trace
);
6919 INIT_LIST_HEAD(&tr
->mod_notrace
);
6923 struct ftrace_ops global_ops
= {
6924 .func
= ftrace_stub
,
6925 .flags
= FTRACE_OPS_FL_INITIALIZED
|
6929 static int __init
ftrace_nodyn_init(void)
6934 core_initcall(ftrace_nodyn_init
);
6936 static inline int ftrace_init_dyn_tracefs(struct dentry
*d_tracer
) { return 0; }
6937 static inline void ftrace_startup_enable(int command
) { }
6938 static inline void ftrace_startup_all(int command
) { }
6940 # define ftrace_startup_sysctl() do { } while (0)
6941 # define ftrace_shutdown_sysctl() do { } while (0)
6943 static void ftrace_update_trampoline(struct ftrace_ops
*ops
)
6947 #endif /* CONFIG_DYNAMIC_FTRACE */
6949 __init
void ftrace_init_global_array_ops(struct trace_array
*tr
)
6951 tr
->ops
= &global_ops
;
6952 tr
->ops
->private = tr
;
6953 ftrace_init_trace_array(tr
);
6956 void ftrace_init_array_ops(struct trace_array
*tr
, ftrace_func_t func
)
6958 /* If we filter on pids, update to use the pid function */
6959 if (tr
->flags
& TRACE_ARRAY_FL_GLOBAL
) {
6960 if (WARN_ON(tr
->ops
->func
!= ftrace_stub
))
6961 printk("ftrace ops had %pS for function\n",
6964 tr
->ops
->func
= func
;
6965 tr
->ops
->private = tr
;
6968 void ftrace_reset_array_ops(struct trace_array
*tr
)
6970 tr
->ops
->func
= ftrace_stub
;
6973 static nokprobe_inline
void
6974 __ftrace_ops_list_func(unsigned long ip
, unsigned long parent_ip
,
6975 struct ftrace_ops
*ignored
, struct ftrace_regs
*fregs
)
6977 struct pt_regs
*regs
= ftrace_get_regs(fregs
);
6978 struct ftrace_ops
*op
;
6981 bit
= trace_test_and_set_recursion(ip
, parent_ip
, TRACE_LIST_START
);
6986 * Some of the ops may be dynamically allocated,
6987 * they must be freed after a synchronize_rcu().
6989 preempt_disable_notrace();
6991 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
6992 /* Stub functions don't need to be called nor tested */
6993 if (op
->flags
& FTRACE_OPS_FL_STUB
)
6996 * Check the following for each ops before calling their func:
6997 * if RCU flag is set, then rcu_is_watching() must be true
6998 * if PER_CPU is set, then ftrace_function_local_disable()
7000 * Otherwise test if the ip matches the ops filter
7002 * If any of the above fails then the op->func() is not executed.
7004 if ((!(op
->flags
& FTRACE_OPS_FL_RCU
) || rcu_is_watching()) &&
7005 ftrace_ops_test(op
, ip
, regs
)) {
7006 if (FTRACE_WARN_ON(!op
->func
)) {
7007 pr_warn("op=%p %pS\n", op
, op
);
7010 op
->func(ip
, parent_ip
, op
, fregs
);
7012 } while_for_each_ftrace_op(op
);
7014 preempt_enable_notrace();
7015 trace_clear_recursion(bit
);
7019 * Some archs only support passing ip and parent_ip. Even though
7020 * the list function ignores the op parameter, we do not want any
7021 * C side effects, where a function is called without the caller
7022 * sending a third parameter.
7023 * Archs are to support both the regs and ftrace_ops at the same time.
7024 * If they support ftrace_ops, it is assumed they support regs.
7025 * If call backs want to use regs, they must either check for regs
7026 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
7027 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
7028 * An architecture can pass partial regs with ftrace_ops and still
7029 * set the ARCH_SUPPORTS_FTRACE_OPS.
7031 #if ARCH_SUPPORTS_FTRACE_OPS
7032 static void ftrace_ops_list_func(unsigned long ip
, unsigned long parent_ip
,
7033 struct ftrace_ops
*op
, struct ftrace_regs
*fregs
)
7035 __ftrace_ops_list_func(ip
, parent_ip
, NULL
, fregs
);
7037 NOKPROBE_SYMBOL(ftrace_ops_list_func
);
7039 static void ftrace_ops_no_ops(unsigned long ip
, unsigned long parent_ip
)
7041 __ftrace_ops_list_func(ip
, parent_ip
, NULL
, NULL
);
7043 NOKPROBE_SYMBOL(ftrace_ops_no_ops
);
7047 * If there's only one function registered but it does not support
7048 * recursion, needs RCU protection and/or requires per cpu handling, then
7049 * this function will be called by the mcount trampoline.
7051 static void ftrace_ops_assist_func(unsigned long ip
, unsigned long parent_ip
,
7052 struct ftrace_ops
*op
, struct ftrace_regs
*fregs
)
7056 bit
= trace_test_and_set_recursion(ip
, parent_ip
, TRACE_LIST_START
);
7060 preempt_disable_notrace();
7062 if (!(op
->flags
& FTRACE_OPS_FL_RCU
) || rcu_is_watching())
7063 op
->func(ip
, parent_ip
, op
, fregs
);
7065 preempt_enable_notrace();
7066 trace_clear_recursion(bit
);
7068 NOKPROBE_SYMBOL(ftrace_ops_assist_func
);
7071 * ftrace_ops_get_func - get the function a trampoline should call
7072 * @ops: the ops to get the function for
7074 * Normally the mcount trampoline will call the ops->func, but there
7075 * are times that it should not. For example, if the ops does not
7076 * have its own recursion protection, then it should call the
7077 * ftrace_ops_assist_func() instead.
7079 * Returns the function that the trampoline should call for @ops.
7081 ftrace_func_t
ftrace_ops_get_func(struct ftrace_ops
*ops
)
7084 * If the function does not handle recursion or needs to be RCU safe,
7085 * then we need to call the assist handler.
7087 if (ops
->flags
& (FTRACE_OPS_FL_RECURSION
|
7089 return ftrace_ops_assist_func
;
7095 ftrace_filter_pid_sched_switch_probe(void *data
, bool preempt
,
7096 struct task_struct
*prev
, struct task_struct
*next
)
7098 struct trace_array
*tr
= data
;
7099 struct trace_pid_list
*pid_list
;
7100 struct trace_pid_list
*no_pid_list
;
7102 pid_list
= rcu_dereference_sched(tr
->function_pids
);
7103 no_pid_list
= rcu_dereference_sched(tr
->function_no_pids
);
7105 if (trace_ignore_this_task(pid_list
, no_pid_list
, next
))
7106 this_cpu_write(tr
->array_buffer
.data
->ftrace_ignore_pid
,
7109 this_cpu_write(tr
->array_buffer
.data
->ftrace_ignore_pid
,
7114 ftrace_pid_follow_sched_process_fork(void *data
,
7115 struct task_struct
*self
,
7116 struct task_struct
*task
)
7118 struct trace_pid_list
*pid_list
;
7119 struct trace_array
*tr
= data
;
7121 pid_list
= rcu_dereference_sched(tr
->function_pids
);
7122 trace_filter_add_remove_task(pid_list
, self
, task
);
7124 pid_list
= rcu_dereference_sched(tr
->function_no_pids
);
7125 trace_filter_add_remove_task(pid_list
, self
, task
);
7129 ftrace_pid_follow_sched_process_exit(void *data
, struct task_struct
*task
)
7131 struct trace_pid_list
*pid_list
;
7132 struct trace_array
*tr
= data
;
7134 pid_list
= rcu_dereference_sched(tr
->function_pids
);
7135 trace_filter_add_remove_task(pid_list
, NULL
, task
);
7137 pid_list
= rcu_dereference_sched(tr
->function_no_pids
);
7138 trace_filter_add_remove_task(pid_list
, NULL
, task
);
7141 void ftrace_pid_follow_fork(struct trace_array
*tr
, bool enable
)
7144 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork
,
7146 register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit
,
7149 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork
,
7151 unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit
,
7156 static void clear_ftrace_pids(struct trace_array
*tr
, int type
)
7158 struct trace_pid_list
*pid_list
;
7159 struct trace_pid_list
*no_pid_list
;
7162 pid_list
= rcu_dereference_protected(tr
->function_pids
,
7163 lockdep_is_held(&ftrace_lock
));
7164 no_pid_list
= rcu_dereference_protected(tr
->function_no_pids
,
7165 lockdep_is_held(&ftrace_lock
));
7167 /* Make sure there's something to do */
7168 if (!pid_type_enabled(type
, pid_list
, no_pid_list
))
7171 /* See if the pids still need to be checked after this */
7172 if (!still_need_pid_events(type
, pid_list
, no_pid_list
)) {
7173 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe
, tr
);
7174 for_each_possible_cpu(cpu
)
7175 per_cpu_ptr(tr
->array_buffer
.data
, cpu
)->ftrace_ignore_pid
= FTRACE_PID_TRACE
;
7178 if (type
& TRACE_PIDS
)
7179 rcu_assign_pointer(tr
->function_pids
, NULL
);
7181 if (type
& TRACE_NO_PIDS
)
7182 rcu_assign_pointer(tr
->function_no_pids
, NULL
);
7184 /* Wait till all users are no longer using pid filtering */
7187 if ((type
& TRACE_PIDS
) && pid_list
)
7188 trace_free_pid_list(pid_list
);
7190 if ((type
& TRACE_NO_PIDS
) && no_pid_list
)
7191 trace_free_pid_list(no_pid_list
);
7194 void ftrace_clear_pids(struct trace_array
*tr
)
7196 mutex_lock(&ftrace_lock
);
7198 clear_ftrace_pids(tr
, TRACE_PIDS
| TRACE_NO_PIDS
);
7200 mutex_unlock(&ftrace_lock
);
7203 static void ftrace_pid_reset(struct trace_array
*tr
, int type
)
7205 mutex_lock(&ftrace_lock
);
7206 clear_ftrace_pids(tr
, type
);
7208 ftrace_update_pid_func();
7209 ftrace_startup_all(0);
7211 mutex_unlock(&ftrace_lock
);
7214 /* Greater than any max PID */
7215 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
7217 static void *fpid_start(struct seq_file
*m
, loff_t
*pos
)
7220 struct trace_pid_list
*pid_list
;
7221 struct trace_array
*tr
= m
->private;
7223 mutex_lock(&ftrace_lock
);
7224 rcu_read_lock_sched();
7226 pid_list
= rcu_dereference_sched(tr
->function_pids
);
7229 return !(*pos
) ? FTRACE_NO_PIDS
: NULL
;
7231 return trace_pid_start(pid_list
, pos
);
7234 static void *fpid_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
7236 struct trace_array
*tr
= m
->private;
7237 struct trace_pid_list
*pid_list
= rcu_dereference_sched(tr
->function_pids
);
7239 if (v
== FTRACE_NO_PIDS
) {
7243 return trace_pid_next(pid_list
, v
, pos
);
7246 static void fpid_stop(struct seq_file
*m
, void *p
)
7249 rcu_read_unlock_sched();
7250 mutex_unlock(&ftrace_lock
);
7253 static int fpid_show(struct seq_file
*m
, void *v
)
7255 if (v
== FTRACE_NO_PIDS
) {
7256 seq_puts(m
, "no pid\n");
7260 return trace_pid_show(m
, v
);
7263 static const struct seq_operations ftrace_pid_sops
= {
7264 .start
= fpid_start
,
7270 static void *fnpid_start(struct seq_file
*m
, loff_t
*pos
)
7273 struct trace_pid_list
*pid_list
;
7274 struct trace_array
*tr
= m
->private;
7276 mutex_lock(&ftrace_lock
);
7277 rcu_read_lock_sched();
7279 pid_list
= rcu_dereference_sched(tr
->function_no_pids
);
7282 return !(*pos
) ? FTRACE_NO_PIDS
: NULL
;
7284 return trace_pid_start(pid_list
, pos
);
7287 static void *fnpid_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
7289 struct trace_array
*tr
= m
->private;
7290 struct trace_pid_list
*pid_list
= rcu_dereference_sched(tr
->function_no_pids
);
7292 if (v
== FTRACE_NO_PIDS
) {
7296 return trace_pid_next(pid_list
, v
, pos
);
7299 static const struct seq_operations ftrace_no_pid_sops
= {
7300 .start
= fnpid_start
,
7306 static int pid_open(struct inode
*inode
, struct file
*file
, int type
)
7308 const struct seq_operations
*seq_ops
;
7309 struct trace_array
*tr
= inode
->i_private
;
7313 ret
= tracing_check_open_get_tr(tr
);
7317 if ((file
->f_mode
& FMODE_WRITE
) &&
7318 (file
->f_flags
& O_TRUNC
))
7319 ftrace_pid_reset(tr
, type
);
7323 seq_ops
= &ftrace_pid_sops
;
7326 seq_ops
= &ftrace_no_pid_sops
;
7329 trace_array_put(tr
);
7334 ret
= seq_open(file
, seq_ops
);
7336 trace_array_put(tr
);
7338 m
= file
->private_data
;
7339 /* copy tr over to seq ops */
7347 ftrace_pid_open(struct inode
*inode
, struct file
*file
)
7349 return pid_open(inode
, file
, TRACE_PIDS
);
7353 ftrace_no_pid_open(struct inode
*inode
, struct file
*file
)
7355 return pid_open(inode
, file
, TRACE_NO_PIDS
);
7358 static void ignore_task_cpu(void *data
)
7360 struct trace_array
*tr
= data
;
7361 struct trace_pid_list
*pid_list
;
7362 struct trace_pid_list
*no_pid_list
;
7365 * This function is called by on_each_cpu() while the
7366 * event_mutex is held.
7368 pid_list
= rcu_dereference_protected(tr
->function_pids
,
7369 mutex_is_locked(&ftrace_lock
));
7370 no_pid_list
= rcu_dereference_protected(tr
->function_no_pids
,
7371 mutex_is_locked(&ftrace_lock
));
7373 if (trace_ignore_this_task(pid_list
, no_pid_list
, current
))
7374 this_cpu_write(tr
->array_buffer
.data
->ftrace_ignore_pid
,
7377 this_cpu_write(tr
->array_buffer
.data
->ftrace_ignore_pid
,
7382 pid_write(struct file
*filp
, const char __user
*ubuf
,
7383 size_t cnt
, loff_t
*ppos
, int type
)
7385 struct seq_file
*m
= filp
->private_data
;
7386 struct trace_array
*tr
= m
->private;
7387 struct trace_pid_list
*filtered_pids
;
7388 struct trace_pid_list
*other_pids
;
7389 struct trace_pid_list
*pid_list
;
7395 mutex_lock(&ftrace_lock
);
7399 filtered_pids
= rcu_dereference_protected(tr
->function_pids
,
7400 lockdep_is_held(&ftrace_lock
));
7401 other_pids
= rcu_dereference_protected(tr
->function_no_pids
,
7402 lockdep_is_held(&ftrace_lock
));
7405 filtered_pids
= rcu_dereference_protected(tr
->function_no_pids
,
7406 lockdep_is_held(&ftrace_lock
));
7407 other_pids
= rcu_dereference_protected(tr
->function_pids
,
7408 lockdep_is_held(&ftrace_lock
));
7416 ret
= trace_pid_write(filtered_pids
, &pid_list
, ubuf
, cnt
);
7422 rcu_assign_pointer(tr
->function_pids
, pid_list
);
7425 rcu_assign_pointer(tr
->function_no_pids
, pid_list
);
7430 if (filtered_pids
) {
7432 trace_free_pid_list(filtered_pids
);
7433 } else if (pid_list
&& !other_pids
) {
7434 /* Register a probe to set whether to ignore the tracing of a task */
7435 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe
, tr
);
7439 * Ignoring of pids is done at task switch. But we have to
7440 * check for those tasks that are currently running.
7441 * Always do this in case a pid was appended or removed.
7443 on_each_cpu(ignore_task_cpu
, tr
, 1);
7445 ftrace_update_pid_func();
7446 ftrace_startup_all(0);
7448 mutex_unlock(&ftrace_lock
);
7457 ftrace_pid_write(struct file
*filp
, const char __user
*ubuf
,
7458 size_t cnt
, loff_t
*ppos
)
7460 return pid_write(filp
, ubuf
, cnt
, ppos
, TRACE_PIDS
);
7464 ftrace_no_pid_write(struct file
*filp
, const char __user
*ubuf
,
7465 size_t cnt
, loff_t
*ppos
)
7467 return pid_write(filp
, ubuf
, cnt
, ppos
, TRACE_NO_PIDS
);
7471 ftrace_pid_release(struct inode
*inode
, struct file
*file
)
7473 struct trace_array
*tr
= inode
->i_private
;
7475 trace_array_put(tr
);
7477 return seq_release(inode
, file
);
7480 static const struct file_operations ftrace_pid_fops
= {
7481 .open
= ftrace_pid_open
,
7482 .write
= ftrace_pid_write
,
7484 .llseek
= tracing_lseek
,
7485 .release
= ftrace_pid_release
,
7488 static const struct file_operations ftrace_no_pid_fops
= {
7489 .open
= ftrace_no_pid_open
,
7490 .write
= ftrace_no_pid_write
,
7492 .llseek
= tracing_lseek
,
7493 .release
= ftrace_pid_release
,
7496 void ftrace_init_tracefs(struct trace_array
*tr
, struct dentry
*d_tracer
)
7498 trace_create_file("set_ftrace_pid", TRACE_MODE_WRITE
, d_tracer
,
7499 tr
, &ftrace_pid_fops
);
7500 trace_create_file("set_ftrace_notrace_pid", TRACE_MODE_WRITE
,
7501 d_tracer
, tr
, &ftrace_no_pid_fops
);
7504 void __init
ftrace_init_tracefs_toplevel(struct trace_array
*tr
,
7505 struct dentry
*d_tracer
)
7507 /* Only the top level directory has the dyn_tracefs and profile */
7508 WARN_ON(!(tr
->flags
& TRACE_ARRAY_FL_GLOBAL
));
7510 ftrace_init_dyn_tracefs(d_tracer
);
7511 ftrace_profile_tracefs(d_tracer
);
7515 * ftrace_kill - kill ftrace
7517 * This function should be used by panic code. It stops ftrace
7518 * but in a not so nice way. If you need to simply kill ftrace
7519 * from a non-atomic section, use ftrace_kill.
7521 void ftrace_kill(void)
7523 ftrace_disabled
= 1;
7525 ftrace_trace_function
= ftrace_stub
;
7529 * ftrace_is_dead - Test if ftrace is dead or not.
7531 * Returns 1 if ftrace is "dead", zero otherwise.
7533 int ftrace_is_dead(void)
7535 return ftrace_disabled
;
7539 * register_ftrace_function - register a function for profiling
7540 * @ops - ops structure that holds the function for profiling.
7542 * Register a function to be called by all functions in the
7545 * Note: @ops->func and all the functions it calls must be labeled
7546 * with "notrace", otherwise it will go into a
7549 int register_ftrace_function(struct ftrace_ops
*ops
)
7553 ftrace_ops_init(ops
);
7555 mutex_lock(&ftrace_lock
);
7557 ret
= ftrace_startup(ops
, 0);
7559 mutex_unlock(&ftrace_lock
);
7563 EXPORT_SYMBOL_GPL(register_ftrace_function
);
7566 * unregister_ftrace_function - unregister a function for profiling.
7567 * @ops - ops structure that holds the function to unregister
7569 * Unregister a function that was added to be called by ftrace profiling.
7571 int unregister_ftrace_function(struct ftrace_ops
*ops
)
7575 mutex_lock(&ftrace_lock
);
7576 ret
= ftrace_shutdown(ops
, 0);
7577 mutex_unlock(&ftrace_lock
);
7581 EXPORT_SYMBOL_GPL(unregister_ftrace_function
);
7583 static bool is_permanent_ops_registered(void)
7585 struct ftrace_ops
*op
;
7587 do_for_each_ftrace_op(op
, ftrace_ops_list
) {
7588 if (op
->flags
& FTRACE_OPS_FL_PERMANENT
)
7590 } while_for_each_ftrace_op(op
);
7596 ftrace_enable_sysctl(struct ctl_table
*table
, int write
,
7597 void *buffer
, size_t *lenp
, loff_t
*ppos
)
7601 mutex_lock(&ftrace_lock
);
7603 if (unlikely(ftrace_disabled
))
7606 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7608 if (ret
|| !write
|| (last_ftrace_enabled
== !!ftrace_enabled
))
7611 if (ftrace_enabled
) {
7613 /* we are starting ftrace again */
7614 if (rcu_dereference_protected(ftrace_ops_list
,
7615 lockdep_is_held(&ftrace_lock
)) != &ftrace_list_end
)
7616 update_ftrace_function();
7618 ftrace_startup_sysctl();
7621 if (is_permanent_ops_registered()) {
7622 ftrace_enabled
= true;
7627 /* stopping ftrace calls (just send to ftrace_stub) */
7628 ftrace_trace_function
= ftrace_stub
;
7630 ftrace_shutdown_sysctl();
7633 last_ftrace_enabled
= !!ftrace_enabled
;
7635 mutex_unlock(&ftrace_lock
);