2 * Infrastructure for profiling code inserted by 'gcc -pg'.
4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
7 * Originally ported from the -rt patch by:
8 * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
10 * Based on code in the latency_tracer, that is:
12 * Copyright (C) 2004-2006 Ingo Molnar
13 * Copyright (C) 2004 William Lee Irwin III
16 #include <linux/stop_machine.h>
17 #include <linux/clocksource.h>
18 #include <linux/kallsyms.h>
19 #include <linux/seq_file.h>
20 #include <linux/suspend.h>
21 #include <linux/debugfs.h>
22 #include <linux/hardirq.h>
23 #include <linux/kthread.h>
24 #include <linux/uaccess.h>
25 #include <linux/bsearch.h>
26 #include <linux/module.h>
27 #include <linux/ftrace.h>
28 #include <linux/sysctl.h>
29 #include <linux/slab.h>
30 #include <linux/ctype.h>
31 #include <linux/sort.h>
32 #include <linux/list.h>
33 #include <linux/hash.h>
34 #include <linux/rcupdate.h>
36 #include <trace/events/sched.h>
38 #include <asm/setup.h>
40 #include "trace_output.h"
41 #include "trace_stat.h"
43 #define FTRACE_WARN_ON(cond) \
51 #define FTRACE_WARN_ON_ONCE(cond) \
54 if (WARN_ON_ONCE(___r)) \
59 /* hash bits for specific function selection */
60 #define FTRACE_HASH_BITS 7
61 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
62 #define FTRACE_HASH_DEFAULT_BITS 10
63 #define FTRACE_HASH_MAX_BITS 12
65 #define FL_GLOBAL_CONTROL_MASK (FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_CONTROL)
67 /* ftrace_enabled is a method to turn ftrace on or off */
68 int ftrace_enabled __read_mostly;
69 static int last_ftrace_enabled;
71 /* Quick disabling of function tracer. */
72 int function_trace_stop;
74 /* List for set_ftrace_pid's pids. */
75 LIST_HEAD(ftrace_pids);
77 struct list_head list;
82 * ftrace_disabled is set when an anomaly is discovered.
83 * ftrace_disabled is much stronger than ftrace_enabled.
85 static int ftrace_disabled __read_mostly;
87 static DEFINE_MUTEX(ftrace_lock);
89 static struct ftrace_ops ftrace_list_end __read_mostly = {
93 static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end;
94 static struct ftrace_ops *ftrace_control_list __read_mostly = &ftrace_list_end;
95 static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
96 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
97 static ftrace_func_t __ftrace_trace_function_delay __read_mostly = ftrace_stub;
98 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
99 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
100 static struct ftrace_ops global_ops;
101 static struct ftrace_ops control_ops;
104 ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip);
107 * Traverse the ftrace_global_list, invoking all entries. The reason that we
108 * can use rcu_dereference_raw() is that elements removed from this list
109 * are simply leaked, so there is no need to interact with a grace-period
110 * mechanism. The rcu_dereference_raw() calls are needed to handle
111 * concurrent insertions into the ftrace_global_list.
113 * Silly Alpha and silly pointer-speculation compiler optimizations!
115 static void ftrace_global_list_func(unsigned long ip,
116 unsigned long parent_ip)
118 struct ftrace_ops *op;
120 if (unlikely(trace_recursion_test(TRACE_GLOBAL_BIT)))
123 trace_recursion_set(TRACE_GLOBAL_BIT);
124 op = rcu_dereference_raw(ftrace_global_list); /*see above*/
125 while (op != &ftrace_list_end) {
126 op->func(ip, parent_ip);
127 op = rcu_dereference_raw(op->next); /*see above*/
129 trace_recursion_clear(TRACE_GLOBAL_BIT);
132 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
134 if (!test_tsk_trace_trace(current))
137 ftrace_pid_function(ip, parent_ip);
140 static void set_ftrace_pid_function(ftrace_func_t func)
142 /* do not set ftrace_pid_function to itself! */
143 if (func != ftrace_pid_func)
144 ftrace_pid_function = func;
148 * clear_ftrace_function - reset the ftrace function
150 * This NULLs the ftrace function and in essence stops
151 * tracing. There may be lag
153 void clear_ftrace_function(void)
155 ftrace_trace_function = ftrace_stub;
156 __ftrace_trace_function = ftrace_stub;
157 __ftrace_trace_function_delay = ftrace_stub;
158 ftrace_pid_function = ftrace_stub;
161 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
163 * For those archs that do not test ftrace_trace_stop in their
164 * mcount call site, we need to do it from C.
166 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
168 if (function_trace_stop)
171 __ftrace_trace_function(ip, parent_ip);
175 static void control_ops_disable_all(struct ftrace_ops *ops)
179 for_each_possible_cpu(cpu)
180 *per_cpu_ptr(ops->disabled, cpu) = 1;
183 static int control_ops_alloc(struct ftrace_ops *ops)
185 int __percpu *disabled;
187 disabled = alloc_percpu(int);
191 ops->disabled = disabled;
192 control_ops_disable_all(ops);
196 static void control_ops_free(struct ftrace_ops *ops)
198 free_percpu(ops->disabled);
201 static void update_global_ops(void)
206 * If there's only one function registered, then call that
207 * function directly. Otherwise, we need to iterate over the
208 * registered callers.
210 if (ftrace_global_list == &ftrace_list_end ||
211 ftrace_global_list->next == &ftrace_list_end)
212 func = ftrace_global_list->func;
214 func = ftrace_global_list_func;
216 /* If we filter on pids, update to use the pid function */
217 if (!list_empty(&ftrace_pids)) {
218 set_ftrace_pid_function(func);
219 func = ftrace_pid_func;
222 global_ops.func = func;
225 static void update_ftrace_function(void)
232 * If we are at the end of the list and this ops is
233 * not dynamic, then have the mcount trampoline call
234 * the function directly
236 if (ftrace_ops_list == &ftrace_list_end ||
237 (ftrace_ops_list->next == &ftrace_list_end &&
238 !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC)))
239 func = ftrace_ops_list->func;
241 func = ftrace_ops_list_func;
243 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
244 ftrace_trace_function = func;
246 #ifdef CONFIG_DYNAMIC_FTRACE
247 /* do not update till all functions have been modified */
248 __ftrace_trace_function_delay = func;
250 __ftrace_trace_function = func;
252 ftrace_trace_function =
253 (func == ftrace_stub) ? func : ftrace_test_stop_func;
257 static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
261 * We are entering ops into the list but another
262 * CPU might be walking that list. We need to make sure
263 * the ops->next pointer is valid before another CPU sees
264 * the ops pointer included into the list.
266 rcu_assign_pointer(*list, ops);
269 static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
271 struct ftrace_ops **p;
274 * If we are removing the last function, then simply point
275 * to the ftrace_stub.
277 if (*list == ops && ops->next == &ftrace_list_end) {
278 *list = &ftrace_list_end;
282 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
293 static void add_ftrace_list_ops(struct ftrace_ops **list,
294 struct ftrace_ops *main_ops,
295 struct ftrace_ops *ops)
297 int first = *list == &ftrace_list_end;
298 add_ftrace_ops(list, ops);
300 add_ftrace_ops(&ftrace_ops_list, main_ops);
303 static int remove_ftrace_list_ops(struct ftrace_ops **list,
304 struct ftrace_ops *main_ops,
305 struct ftrace_ops *ops)
307 int ret = remove_ftrace_ops(list, ops);
308 if (!ret && *list == &ftrace_list_end)
309 ret = remove_ftrace_ops(&ftrace_ops_list, main_ops);
313 static int __register_ftrace_function(struct ftrace_ops *ops)
318 if (FTRACE_WARN_ON(ops == &global_ops))
321 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
324 /* We don't support both control and global flags set. */
325 if ((ops->flags & FL_GLOBAL_CONTROL_MASK) == FL_GLOBAL_CONTROL_MASK)
328 if (!core_kernel_data((unsigned long)ops))
329 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
331 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
332 add_ftrace_list_ops(&ftrace_global_list, &global_ops, ops);
333 ops->flags |= FTRACE_OPS_FL_ENABLED;
334 } else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
335 if (control_ops_alloc(ops))
337 add_ftrace_list_ops(&ftrace_control_list, &control_ops, ops);
339 add_ftrace_ops(&ftrace_ops_list, ops);
342 update_ftrace_function();
347 static int __unregister_ftrace_function(struct ftrace_ops *ops)
354 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
357 if (FTRACE_WARN_ON(ops == &global_ops))
360 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
361 ret = remove_ftrace_list_ops(&ftrace_global_list,
364 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
365 } else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
366 ret = remove_ftrace_list_ops(&ftrace_control_list,
370 * The ftrace_ops is now removed from the list,
371 * so there'll be no new users. We must ensure
372 * all current users are done before we free
376 control_ops_free(ops);
379 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
385 update_ftrace_function();
388 * Dynamic ops may be freed, we must make sure that all
389 * callers are done before leaving this function.
391 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
397 static void ftrace_update_pid_func(void)
399 /* Only do something if we are tracing something */
400 if (ftrace_trace_function == ftrace_stub)
403 update_ftrace_function();
406 #ifdef CONFIG_FUNCTION_PROFILER
407 struct ftrace_profile {
408 struct hlist_node node;
410 unsigned long counter;
411 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
412 unsigned long long time;
413 unsigned long long time_squared;
417 struct ftrace_profile_page {
418 struct ftrace_profile_page *next;
420 struct ftrace_profile records[];
423 struct ftrace_profile_stat {
425 struct hlist_head *hash;
426 struct ftrace_profile_page *pages;
427 struct ftrace_profile_page *start;
428 struct tracer_stat stat;
431 #define PROFILE_RECORDS_SIZE \
432 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
434 #define PROFILES_PER_PAGE \
435 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
437 static int ftrace_profile_bits __read_mostly;
438 static int ftrace_profile_enabled __read_mostly;
440 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
441 static DEFINE_MUTEX(ftrace_profile_lock);
443 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
445 #define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
448 function_stat_next(void *v, int idx)
450 struct ftrace_profile *rec = v;
451 struct ftrace_profile_page *pg;
453 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
459 if ((void *)rec >= (void *)&pg->records[pg->index]) {
463 rec = &pg->records[0];
471 static void *function_stat_start(struct tracer_stat *trace)
473 struct ftrace_profile_stat *stat =
474 container_of(trace, struct ftrace_profile_stat, stat);
476 if (!stat || !stat->start)
479 return function_stat_next(&stat->start->records[0], 0);
482 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
483 /* function graph compares on total time */
484 static int function_stat_cmp(void *p1, void *p2)
486 struct ftrace_profile *a = p1;
487 struct ftrace_profile *b = p2;
489 if (a->time < b->time)
491 if (a->time > b->time)
497 /* not function graph compares against hits */
498 static int function_stat_cmp(void *p1, void *p2)
500 struct ftrace_profile *a = p1;
501 struct ftrace_profile *b = p2;
503 if (a->counter < b->counter)
505 if (a->counter > b->counter)
512 static int function_stat_headers(struct seq_file *m)
514 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
515 seq_printf(m, " Function "
518 "--- ---- --- ---\n");
520 seq_printf(m, " Function Hit\n"
526 static int function_stat_show(struct seq_file *m, void *v)
528 struct ftrace_profile *rec = v;
529 char str[KSYM_SYMBOL_LEN];
531 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
532 static struct trace_seq s;
533 unsigned long long avg;
534 unsigned long long stddev;
536 mutex_lock(&ftrace_profile_lock);
538 /* we raced with function_profile_reset() */
539 if (unlikely(rec->counter == 0)) {
544 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
545 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
547 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
550 do_div(avg, rec->counter);
552 /* Sample standard deviation (s^2) */
553 if (rec->counter <= 1)
556 stddev = rec->time_squared - rec->counter * avg * avg;
558 * Divide only 1000 for ns^2 -> us^2 conversion.
559 * trace_print_graph_duration will divide 1000 again.
561 do_div(stddev, (rec->counter - 1) * 1000);
565 trace_print_graph_duration(rec->time, &s);
566 trace_seq_puts(&s, " ");
567 trace_print_graph_duration(avg, &s);
568 trace_seq_puts(&s, " ");
569 trace_print_graph_duration(stddev, &s);
570 trace_print_seq(m, &s);
574 mutex_unlock(&ftrace_profile_lock);
579 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
581 struct ftrace_profile_page *pg;
583 pg = stat->pages = stat->start;
586 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
591 memset(stat->hash, 0,
592 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
595 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
597 struct ftrace_profile_page *pg;
602 /* If we already allocated, do nothing */
606 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
610 #ifdef CONFIG_DYNAMIC_FTRACE
611 functions = ftrace_update_tot_cnt;
614 * We do not know the number of functions that exist because
615 * dynamic tracing is what counts them. With past experience
616 * we have around 20K functions. That should be more than enough.
617 * It is highly unlikely we will execute every function in
623 pg = stat->start = stat->pages;
625 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
627 for (i = 0; i < pages; i++) {
628 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
639 unsigned long tmp = (unsigned long)pg;
645 free_page((unsigned long)stat->pages);
652 static int ftrace_profile_init_cpu(int cpu)
654 struct ftrace_profile_stat *stat;
657 stat = &per_cpu(ftrace_profile_stats, cpu);
660 /* If the profile is already created, simply reset it */
661 ftrace_profile_reset(stat);
666 * We are profiling all functions, but usually only a few thousand
667 * functions are hit. We'll make a hash of 1024 items.
669 size = FTRACE_PROFILE_HASH_SIZE;
671 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
676 if (!ftrace_profile_bits) {
679 for (; size; size >>= 1)
680 ftrace_profile_bits++;
683 /* Preallocate the function profiling pages */
684 if (ftrace_profile_pages_init(stat) < 0) {
693 static int ftrace_profile_init(void)
698 for_each_online_cpu(cpu) {
699 ret = ftrace_profile_init_cpu(cpu);
707 /* interrupts must be disabled */
708 static struct ftrace_profile *
709 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
711 struct ftrace_profile *rec;
712 struct hlist_head *hhd;
713 struct hlist_node *n;
716 key = hash_long(ip, ftrace_profile_bits);
717 hhd = &stat->hash[key];
719 if (hlist_empty(hhd))
722 hlist_for_each_entry_rcu(rec, n, hhd, node) {
730 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
731 struct ftrace_profile *rec)
735 key = hash_long(rec->ip, ftrace_profile_bits);
736 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
740 * The memory is already allocated, this simply finds a new record to use.
742 static struct ftrace_profile *
743 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
745 struct ftrace_profile *rec = NULL;
747 /* prevent recursion (from NMIs) */
748 if (atomic_inc_return(&stat->disabled) != 1)
752 * Try to find the function again since an NMI
753 * could have added it
755 rec = ftrace_find_profiled_func(stat, ip);
759 if (stat->pages->index == PROFILES_PER_PAGE) {
760 if (!stat->pages->next)
762 stat->pages = stat->pages->next;
765 rec = &stat->pages->records[stat->pages->index++];
767 ftrace_add_profile(stat, rec);
770 atomic_dec(&stat->disabled);
776 function_profile_call(unsigned long ip, unsigned long parent_ip)
778 struct ftrace_profile_stat *stat;
779 struct ftrace_profile *rec;
782 if (!ftrace_profile_enabled)
785 local_irq_save(flags);
787 stat = &__get_cpu_var(ftrace_profile_stats);
788 if (!stat->hash || !ftrace_profile_enabled)
791 rec = ftrace_find_profiled_func(stat, ip);
793 rec = ftrace_profile_alloc(stat, ip);
800 local_irq_restore(flags);
803 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
804 static int profile_graph_entry(struct ftrace_graph_ent *trace)
806 function_profile_call(trace->func, 0);
810 static void profile_graph_return(struct ftrace_graph_ret *trace)
812 struct ftrace_profile_stat *stat;
813 unsigned long long calltime;
814 struct ftrace_profile *rec;
817 local_irq_save(flags);
818 stat = &__get_cpu_var(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 (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
831 index = trace->depth;
833 /* Append this call time to the parent time to subtract */
835 current->ret_stack[index - 1].subtime += calltime;
837 if (current->ret_stack[index].subtime < calltime)
838 calltime -= current->ret_stack[index].subtime;
843 rec = ftrace_find_profiled_func(stat, trace->func);
845 rec->time += calltime;
846 rec->time_squared += calltime * calltime;
850 local_irq_restore(flags);
853 static int register_ftrace_profiler(void)
855 return register_ftrace_graph(&profile_graph_return,
856 &profile_graph_entry);
859 static void unregister_ftrace_profiler(void)
861 unregister_ftrace_graph();
864 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
865 .func = function_profile_call,
868 static int register_ftrace_profiler(void)
870 return register_ftrace_function(&ftrace_profile_ops);
873 static void unregister_ftrace_profiler(void)
875 unregister_ftrace_function(&ftrace_profile_ops);
877 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
880 ftrace_profile_write(struct file *filp, const char __user *ubuf,
881 size_t cnt, loff_t *ppos)
886 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
892 mutex_lock(&ftrace_profile_lock);
893 if (ftrace_profile_enabled ^ val) {
895 ret = ftrace_profile_init();
901 ret = register_ftrace_profiler();
906 ftrace_profile_enabled = 1;
908 ftrace_profile_enabled = 0;
910 * unregister_ftrace_profiler calls stop_machine
911 * so this acts like an synchronize_sched.
913 unregister_ftrace_profiler();
917 mutex_unlock(&ftrace_profile_lock);
925 ftrace_profile_read(struct file *filp, char __user *ubuf,
926 size_t cnt, loff_t *ppos)
928 char buf[64]; /* big enough to hold a number */
931 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
932 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
935 static const struct file_operations ftrace_profile_fops = {
936 .open = tracing_open_generic,
937 .read = ftrace_profile_read,
938 .write = ftrace_profile_write,
939 .llseek = default_llseek,
942 /* used to initialize the real stat files */
943 static struct tracer_stat function_stats __initdata = {
945 .stat_start = function_stat_start,
946 .stat_next = function_stat_next,
947 .stat_cmp = function_stat_cmp,
948 .stat_headers = function_stat_headers,
949 .stat_show = function_stat_show
952 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
954 struct ftrace_profile_stat *stat;
955 struct dentry *entry;
960 for_each_possible_cpu(cpu) {
961 stat = &per_cpu(ftrace_profile_stats, cpu);
963 /* allocate enough for function name + cpu number */
964 name = kmalloc(32, GFP_KERNEL);
967 * The files created are permanent, if something happens
968 * we still do not free memory.
971 "Could not allocate stat file for cpu %d\n",
975 stat->stat = function_stats;
976 snprintf(name, 32, "function%d", cpu);
977 stat->stat.name = name;
978 ret = register_stat_tracer(&stat->stat);
981 "Could not register function stat for cpu %d\n",
988 entry = debugfs_create_file("function_profile_enabled", 0644,
989 d_tracer, NULL, &ftrace_profile_fops);
991 pr_warning("Could not create debugfs "
992 "'function_profile_enabled' entry\n");
995 #else /* CONFIG_FUNCTION_PROFILER */
996 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
999 #endif /* CONFIG_FUNCTION_PROFILER */
1001 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1003 #ifdef CONFIG_DYNAMIC_FTRACE
1005 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1006 # error Dynamic ftrace depends on MCOUNT_RECORD
1009 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
1011 struct ftrace_func_probe {
1012 struct hlist_node node;
1013 struct ftrace_probe_ops *ops;
1014 unsigned long flags;
1017 struct rcu_head rcu;
1020 struct ftrace_func_entry {
1021 struct hlist_node hlist;
1025 struct ftrace_hash {
1026 unsigned long size_bits;
1027 struct hlist_head *buckets;
1028 unsigned long count;
1029 struct rcu_head rcu;
1033 * We make these constant because no one should touch them,
1034 * but they are used as the default "empty hash", to avoid allocating
1035 * it all the time. These are in a read only section such that if
1036 * anyone does try to modify it, it will cause an exception.
1038 static const struct hlist_head empty_buckets[1];
1039 static const struct ftrace_hash empty_hash = {
1040 .buckets = (struct hlist_head *)empty_buckets,
1042 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1044 static struct ftrace_ops global_ops = {
1045 .func = ftrace_stub,
1046 .notrace_hash = EMPTY_HASH,
1047 .filter_hash = EMPTY_HASH,
1050 static DEFINE_MUTEX(ftrace_regex_lock);
1052 struct ftrace_page {
1053 struct ftrace_page *next;
1054 struct dyn_ftrace *records;
1059 static struct ftrace_page *ftrace_new_pgs;
1061 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1062 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1064 /* estimate from running different kernels */
1065 #define NR_TO_INIT 10000
1067 static struct ftrace_page *ftrace_pages_start;
1068 static struct ftrace_page *ftrace_pages;
1070 static bool ftrace_hash_empty(struct ftrace_hash *hash)
1072 return !hash || !hash->count;
1075 static struct ftrace_func_entry *
1076 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1079 struct ftrace_func_entry *entry;
1080 struct hlist_head *hhd;
1081 struct hlist_node *n;
1083 if (ftrace_hash_empty(hash))
1086 if (hash->size_bits > 0)
1087 key = hash_long(ip, hash->size_bits);
1091 hhd = &hash->buckets[key];
1093 hlist_for_each_entry_rcu(entry, n, hhd, hlist) {
1094 if (entry->ip == ip)
1100 static void __add_hash_entry(struct ftrace_hash *hash,
1101 struct ftrace_func_entry *entry)
1103 struct hlist_head *hhd;
1106 if (hash->size_bits)
1107 key = hash_long(entry->ip, hash->size_bits);
1111 hhd = &hash->buckets[key];
1112 hlist_add_head(&entry->hlist, hhd);
1116 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1118 struct ftrace_func_entry *entry;
1120 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1125 __add_hash_entry(hash, entry);
1131 free_hash_entry(struct ftrace_hash *hash,
1132 struct ftrace_func_entry *entry)
1134 hlist_del(&entry->hlist);
1140 remove_hash_entry(struct ftrace_hash *hash,
1141 struct ftrace_func_entry *entry)
1143 hlist_del(&entry->hlist);
1147 static void ftrace_hash_clear(struct ftrace_hash *hash)
1149 struct hlist_head *hhd;
1150 struct hlist_node *tp, *tn;
1151 struct ftrace_func_entry *entry;
1152 int size = 1 << hash->size_bits;
1158 for (i = 0; i < size; i++) {
1159 hhd = &hash->buckets[i];
1160 hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist)
1161 free_hash_entry(hash, entry);
1163 FTRACE_WARN_ON(hash->count);
1166 static void free_ftrace_hash(struct ftrace_hash *hash)
1168 if (!hash || hash == EMPTY_HASH)
1170 ftrace_hash_clear(hash);
1171 kfree(hash->buckets);
1175 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1177 struct ftrace_hash *hash;
1179 hash = container_of(rcu, struct ftrace_hash, rcu);
1180 free_ftrace_hash(hash);
1183 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1185 if (!hash || hash == EMPTY_HASH)
1187 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1190 void ftrace_free_filter(struct ftrace_ops *ops)
1192 free_ftrace_hash(ops->filter_hash);
1193 free_ftrace_hash(ops->notrace_hash);
1196 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1198 struct ftrace_hash *hash;
1201 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1205 size = 1 << size_bits;
1206 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1208 if (!hash->buckets) {
1213 hash->size_bits = size_bits;
1218 static struct ftrace_hash *
1219 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1221 struct ftrace_func_entry *entry;
1222 struct ftrace_hash *new_hash;
1223 struct hlist_node *tp;
1228 new_hash = alloc_ftrace_hash(size_bits);
1233 if (ftrace_hash_empty(hash))
1236 size = 1 << hash->size_bits;
1237 for (i = 0; i < size; i++) {
1238 hlist_for_each_entry(entry, tp, &hash->buckets[i], hlist) {
1239 ret = add_hash_entry(new_hash, entry->ip);
1245 FTRACE_WARN_ON(new_hash->count != hash->count);
1250 free_ftrace_hash(new_hash);
1255 ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash);
1257 ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash);
1260 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1261 struct ftrace_hash **dst, struct ftrace_hash *src)
1263 struct ftrace_func_entry *entry;
1264 struct hlist_node *tp, *tn;
1265 struct hlist_head *hhd;
1266 struct ftrace_hash *old_hash;
1267 struct ftrace_hash *new_hash;
1269 int size = src->count;
1275 * Remove the current set, update the hash and add
1278 ftrace_hash_rec_disable(ops, enable);
1281 * If the new source is empty, just free dst and assign it
1285 free_ftrace_hash_rcu(*dst);
1286 rcu_assign_pointer(*dst, EMPTY_HASH);
1287 /* still need to update the function records */
1293 * Make the hash size about 1/2 the # found
1295 for (size /= 2; size; size >>= 1)
1298 /* Don't allocate too much */
1299 if (bits > FTRACE_HASH_MAX_BITS)
1300 bits = FTRACE_HASH_MAX_BITS;
1303 new_hash = alloc_ftrace_hash(bits);
1307 size = 1 << src->size_bits;
1308 for (i = 0; i < size; i++) {
1309 hhd = &src->buckets[i];
1310 hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist) {
1312 key = hash_long(entry->ip, bits);
1315 remove_hash_entry(src, entry);
1316 __add_hash_entry(new_hash, entry);
1321 rcu_assign_pointer(*dst, new_hash);
1322 free_ftrace_hash_rcu(old_hash);
1327 * Enable regardless of ret:
1328 * On success, we enable the new hash.
1329 * On failure, we re-enable the original hash.
1331 ftrace_hash_rec_enable(ops, enable);
1337 * Test the hashes for this ops to see if we want to call
1338 * the ops->func or not.
1340 * It's a match if the ip is in the ops->filter_hash or
1341 * the filter_hash does not exist or is empty,
1343 * the ip is not in the ops->notrace_hash.
1345 * This needs to be called with preemption disabled as
1346 * the hashes are freed with call_rcu_sched().
1349 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
1351 struct ftrace_hash *filter_hash;
1352 struct ftrace_hash *notrace_hash;
1355 filter_hash = rcu_dereference_raw(ops->filter_hash);
1356 notrace_hash = rcu_dereference_raw(ops->notrace_hash);
1358 if ((ftrace_hash_empty(filter_hash) ||
1359 ftrace_lookup_ip(filter_hash, ip)) &&
1360 (ftrace_hash_empty(notrace_hash) ||
1361 !ftrace_lookup_ip(notrace_hash, ip)))
1370 * This is a double for. Do not use 'break' to break out of the loop,
1371 * you must use a goto.
1373 #define do_for_each_ftrace_rec(pg, rec) \
1374 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1376 for (_____i = 0; _____i < pg->index; _____i++) { \
1377 rec = &pg->records[_____i];
1379 #define while_for_each_ftrace_rec() \
1384 static int ftrace_cmp_recs(const void *a, const void *b)
1386 const struct dyn_ftrace *reca = a;
1387 const struct dyn_ftrace *recb = b;
1389 if (reca->ip > recb->ip)
1391 if (reca->ip < recb->ip)
1397 * ftrace_location - return true if the ip giving is a traced location
1398 * @ip: the instruction pointer to check
1400 * Returns 1 if @ip given is a pointer to a ftrace location.
1401 * That is, the instruction that is either a NOP or call to
1402 * the function tracer. It checks the ftrace internal tables to
1403 * determine if the address belongs or not.
1405 int ftrace_location(unsigned long ip)
1407 struct ftrace_page *pg;
1408 struct dyn_ftrace *rec;
1409 struct dyn_ftrace key;
1413 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1414 rec = bsearch(&key, pg->records, pg->index,
1415 sizeof(struct dyn_ftrace),
1424 static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
1428 struct ftrace_hash *hash;
1429 struct ftrace_hash *other_hash;
1430 struct ftrace_page *pg;
1431 struct dyn_ftrace *rec;
1435 /* Only update if the ops has been registered */
1436 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1440 * In the filter_hash case:
1441 * If the count is zero, we update all records.
1442 * Otherwise we just update the items in the hash.
1444 * In the notrace_hash case:
1445 * We enable the update in the hash.
1446 * As disabling notrace means enabling the tracing,
1447 * and enabling notrace means disabling, the inc variable
1451 hash = ops->filter_hash;
1452 other_hash = ops->notrace_hash;
1453 if (ftrace_hash_empty(hash))
1457 hash = ops->notrace_hash;
1458 other_hash = ops->filter_hash;
1460 * If the notrace hash has no items,
1461 * then there's nothing to do.
1463 if (ftrace_hash_empty(hash))
1467 do_for_each_ftrace_rec(pg, rec) {
1468 int in_other_hash = 0;
1474 * Only the filter_hash affects all records.
1475 * Update if the record is not in the notrace hash.
1477 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1480 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1481 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1486 if (filter_hash && in_hash && !in_other_hash)
1488 else if (!filter_hash && in_hash &&
1489 (in_other_hash || ftrace_hash_empty(other_hash)))
1497 if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX))
1500 if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
1505 /* Shortcut, if we handled all records, we are done. */
1506 if (!all && count == hash->count)
1508 } while_for_each_ftrace_rec();
1511 static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
1514 __ftrace_hash_rec_update(ops, filter_hash, 0);
1517 static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
1520 __ftrace_hash_rec_update(ops, filter_hash, 1);
1523 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
1525 if (ftrace_pages->index == ftrace_pages->size) {
1526 /* We should have allocated enough */
1527 if (WARN_ON(!ftrace_pages->next))
1529 ftrace_pages = ftrace_pages->next;
1532 return &ftrace_pages->records[ftrace_pages->index++];
1535 static struct dyn_ftrace *
1536 ftrace_record_ip(unsigned long ip)
1538 struct dyn_ftrace *rec;
1540 if (ftrace_disabled)
1543 rec = ftrace_alloc_dyn_node(ip);
1552 static void print_ip_ins(const char *fmt, unsigned char *p)
1556 printk(KERN_CONT "%s", fmt);
1558 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1559 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1563 * ftrace_bug - report and shutdown function tracer
1564 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1565 * @ip: The address that failed
1567 * The arch code that enables or disables the function tracing
1568 * can call ftrace_bug() when it has detected a problem in
1569 * modifying the code. @failed should be one of either:
1570 * EFAULT - if the problem happens on reading the @ip address
1571 * EINVAL - if what is read at @ip is not what was expected
1572 * EPERM - if the problem happens on writting to the @ip address
1574 void ftrace_bug(int failed, unsigned long ip)
1578 FTRACE_WARN_ON_ONCE(1);
1579 pr_info("ftrace faulted on modifying ");
1583 FTRACE_WARN_ON_ONCE(1);
1584 pr_info("ftrace failed to modify ");
1586 print_ip_ins(" actual: ", (unsigned char *)ip);
1587 printk(KERN_CONT "\n");
1590 FTRACE_WARN_ON_ONCE(1);
1591 pr_info("ftrace faulted on writing ");
1595 FTRACE_WARN_ON_ONCE(1);
1596 pr_info("ftrace faulted on unknown error ");
1602 /* Return 1 if the address range is reserved for ftrace */
1603 int ftrace_text_reserved(void *start, void *end)
1605 struct dyn_ftrace *rec;
1606 struct ftrace_page *pg;
1608 do_for_each_ftrace_rec(pg, rec) {
1609 if (rec->ip <= (unsigned long)end &&
1610 rec->ip + MCOUNT_INSN_SIZE > (unsigned long)start)
1612 } while_for_each_ftrace_rec();
1616 static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
1618 unsigned long flag = 0UL;
1621 * If we are updating calls:
1623 * If the record has a ref count, then we need to enable it
1624 * because someone is using it.
1626 * Otherwise we make sure its disabled.
1628 * If we are disabling calls, then disable all records that
1631 if (enable && (rec->flags & ~FTRACE_FL_MASK))
1632 flag = FTRACE_FL_ENABLED;
1634 /* If the state of this record hasn't changed, then do nothing */
1635 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1636 return FTRACE_UPDATE_IGNORE;
1640 rec->flags |= FTRACE_FL_ENABLED;
1641 return FTRACE_UPDATE_MAKE_CALL;
1645 rec->flags &= ~FTRACE_FL_ENABLED;
1647 return FTRACE_UPDATE_MAKE_NOP;
1651 * ftrace_update_record, set a record that now is tracing or not
1652 * @rec: the record to update
1653 * @enable: set to 1 if the record is tracing, zero to force disable
1655 * The records that represent all functions that can be traced need
1656 * to be updated when tracing has been enabled.
1658 int ftrace_update_record(struct dyn_ftrace *rec, int enable)
1660 return ftrace_check_record(rec, enable, 1);
1664 * ftrace_test_record, check if the record has been enabled or not
1665 * @rec: the record to test
1666 * @enable: set to 1 to check if enabled, 0 if it is disabled
1668 * The arch code may need to test if a record is already set to
1669 * tracing to determine how to modify the function code that it
1672 int ftrace_test_record(struct dyn_ftrace *rec, int enable)
1674 return ftrace_check_record(rec, enable, 0);
1678 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1680 unsigned long ftrace_addr;
1683 ftrace_addr = (unsigned long)FTRACE_ADDR;
1685 ret = ftrace_update_record(rec, enable);
1688 case FTRACE_UPDATE_IGNORE:
1691 case FTRACE_UPDATE_MAKE_CALL:
1692 return ftrace_make_call(rec, ftrace_addr);
1694 case FTRACE_UPDATE_MAKE_NOP:
1695 return ftrace_make_nop(NULL, rec, ftrace_addr);
1698 return -1; /* unknow ftrace bug */
1701 static void ftrace_replace_code(int update)
1703 struct dyn_ftrace *rec;
1704 struct ftrace_page *pg;
1707 if (unlikely(ftrace_disabled))
1710 do_for_each_ftrace_rec(pg, rec) {
1711 failed = __ftrace_replace_code(rec, update);
1713 ftrace_bug(failed, rec->ip);
1714 /* Stop processing */
1717 } while_for_each_ftrace_rec();
1720 struct ftrace_rec_iter {
1721 struct ftrace_page *pg;
1726 * ftrace_rec_iter_start, start up iterating over traced functions
1728 * Returns an iterator handle that is used to iterate over all
1729 * the records that represent address locations where functions
1732 * May return NULL if no records are available.
1734 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
1737 * We only use a single iterator.
1738 * Protected by the ftrace_lock mutex.
1740 static struct ftrace_rec_iter ftrace_rec_iter;
1741 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
1743 iter->pg = ftrace_pages_start;
1746 /* Could have empty pages */
1747 while (iter->pg && !iter->pg->index)
1748 iter->pg = iter->pg->next;
1757 * ftrace_rec_iter_next, get the next record to process.
1758 * @iter: The handle to the iterator.
1760 * Returns the next iterator after the given iterator @iter.
1762 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
1766 if (iter->index >= iter->pg->index) {
1767 iter->pg = iter->pg->next;
1770 /* Could have empty pages */
1771 while (iter->pg && !iter->pg->index)
1772 iter->pg = iter->pg->next;
1782 * ftrace_rec_iter_record, get the record at the iterator location
1783 * @iter: The current iterator location
1785 * Returns the record that the current @iter is at.
1787 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
1789 return &iter->pg->records[iter->index];
1793 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1800 if (unlikely(ftrace_disabled))
1803 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1805 ftrace_bug(ret, ip);
1812 * archs can override this function if they must do something
1813 * before the modifying code is performed.
1815 int __weak ftrace_arch_code_modify_prepare(void)
1821 * archs can override this function if they must do something
1822 * after the modifying code is performed.
1824 int __weak ftrace_arch_code_modify_post_process(void)
1829 static int __ftrace_modify_code(void *data)
1831 int *command = data;
1833 if (*command & FTRACE_UPDATE_CALLS)
1834 ftrace_replace_code(1);
1835 else if (*command & FTRACE_DISABLE_CALLS)
1836 ftrace_replace_code(0);
1838 if (*command & FTRACE_UPDATE_TRACE_FUNC)
1839 ftrace_update_ftrace_func(ftrace_trace_function);
1841 if (*command & FTRACE_START_FUNC_RET)
1842 ftrace_enable_ftrace_graph_caller();
1843 else if (*command & FTRACE_STOP_FUNC_RET)
1844 ftrace_disable_ftrace_graph_caller();
1850 * ftrace_run_stop_machine, go back to the stop machine method
1851 * @command: The command to tell ftrace what to do
1853 * If an arch needs to fall back to the stop machine method, the
1854 * it can call this function.
1856 void ftrace_run_stop_machine(int command)
1858 stop_machine(__ftrace_modify_code, &command, NULL);
1862 * arch_ftrace_update_code, modify the code to trace or not trace
1863 * @command: The command that needs to be done
1865 * Archs can override this function if it does not need to
1866 * run stop_machine() to modify code.
1868 void __weak arch_ftrace_update_code(int command)
1870 ftrace_run_stop_machine(command);
1873 static void ftrace_run_update_code(int command)
1877 ret = ftrace_arch_code_modify_prepare();
1878 FTRACE_WARN_ON(ret);
1882 * Do not call function tracer while we update the code.
1883 * We are in stop machine.
1885 function_trace_stop++;
1888 * By default we use stop_machine() to modify the code.
1889 * But archs can do what ever they want as long as it
1890 * is safe. The stop_machine() is the safest, but also
1891 * produces the most overhead.
1893 arch_ftrace_update_code(command);
1895 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
1897 * For archs that call ftrace_test_stop_func(), we must
1898 * wait till after we update all the function callers
1899 * before we update the callback. This keeps different
1900 * ops that record different functions from corrupting
1903 __ftrace_trace_function = __ftrace_trace_function_delay;
1905 function_trace_stop--;
1907 ret = ftrace_arch_code_modify_post_process();
1908 FTRACE_WARN_ON(ret);
1911 static ftrace_func_t saved_ftrace_func;
1912 static int ftrace_start_up;
1913 static int global_start_up;
1915 static void ftrace_startup_enable(int command)
1917 if (saved_ftrace_func != ftrace_trace_function) {
1918 saved_ftrace_func = ftrace_trace_function;
1919 command |= FTRACE_UPDATE_TRACE_FUNC;
1922 if (!command || !ftrace_enabled)
1925 ftrace_run_update_code(command);
1928 static int ftrace_startup(struct ftrace_ops *ops, int command)
1930 bool hash_enable = true;
1932 if (unlikely(ftrace_disabled))
1936 command |= FTRACE_UPDATE_CALLS;
1938 /* ops marked global share the filter hashes */
1939 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
1941 /* Don't update hash if global is already set */
1942 if (global_start_up)
1943 hash_enable = false;
1947 ops->flags |= FTRACE_OPS_FL_ENABLED;
1949 ftrace_hash_rec_enable(ops, 1);
1951 ftrace_startup_enable(command);
1956 static void ftrace_shutdown(struct ftrace_ops *ops, int command)
1958 bool hash_disable = true;
1960 if (unlikely(ftrace_disabled))
1965 * Just warn in case of unbalance, no need to kill ftrace, it's not
1966 * critical but the ftrace_call callers may be never nopped again after
1967 * further ftrace uses.
1969 WARN_ON_ONCE(ftrace_start_up < 0);
1971 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
1974 WARN_ON_ONCE(global_start_up < 0);
1975 /* Don't update hash if global still has users */
1976 if (global_start_up) {
1977 WARN_ON_ONCE(!ftrace_start_up);
1978 hash_disable = false;
1983 ftrace_hash_rec_disable(ops, 1);
1985 if (ops != &global_ops || !global_start_up)
1986 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
1988 command |= FTRACE_UPDATE_CALLS;
1990 if (saved_ftrace_func != ftrace_trace_function) {
1991 saved_ftrace_func = ftrace_trace_function;
1992 command |= FTRACE_UPDATE_TRACE_FUNC;
1995 if (!command || !ftrace_enabled)
1998 ftrace_run_update_code(command);
2001 static void ftrace_startup_sysctl(void)
2003 if (unlikely(ftrace_disabled))
2006 /* Force update next time */
2007 saved_ftrace_func = NULL;
2008 /* ftrace_start_up is true if we want ftrace running */
2009 if (ftrace_start_up)
2010 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
2013 static void ftrace_shutdown_sysctl(void)
2015 if (unlikely(ftrace_disabled))
2018 /* ftrace_start_up is true if ftrace is running */
2019 if (ftrace_start_up)
2020 ftrace_run_update_code(FTRACE_DISABLE_CALLS);
2023 static cycle_t ftrace_update_time;
2024 static unsigned long ftrace_update_cnt;
2025 unsigned long ftrace_update_tot_cnt;
2027 static int ops_traces_mod(struct ftrace_ops *ops)
2029 struct ftrace_hash *hash;
2031 hash = ops->filter_hash;
2032 return ftrace_hash_empty(hash);
2035 static int ftrace_update_code(struct module *mod)
2037 struct ftrace_page *pg;
2038 struct dyn_ftrace *p;
2039 cycle_t start, stop;
2040 unsigned long ref = 0;
2044 * When adding a module, we need to check if tracers are
2045 * currently enabled and if they are set to trace all functions.
2046 * If they are, we need to enable the module functions as well
2047 * as update the reference counts for those function records.
2050 struct ftrace_ops *ops;
2052 for (ops = ftrace_ops_list;
2053 ops != &ftrace_list_end; ops = ops->next) {
2054 if (ops->flags & FTRACE_OPS_FL_ENABLED &&
2055 ops_traces_mod(ops))
2060 start = ftrace_now(raw_smp_processor_id());
2061 ftrace_update_cnt = 0;
2063 for (pg = ftrace_new_pgs; pg; pg = pg->next) {
2065 for (i = 0; i < pg->index; i++) {
2066 /* If something went wrong, bail without enabling anything */
2067 if (unlikely(ftrace_disabled))
2070 p = &pg->records[i];
2074 * Do the initial record conversion from mcount jump
2075 * to the NOP instructions.
2077 if (!ftrace_code_disable(mod, p))
2080 ftrace_update_cnt++;
2083 * If the tracing is enabled, go ahead and enable the record.
2085 * The reason not to enable the record immediatelly is the
2086 * inherent check of ftrace_make_nop/ftrace_make_call for
2087 * correct previous instructions. Making first the NOP
2088 * conversion puts the module to the correct state, thus
2089 * passing the ftrace_make_call check.
2091 if (ftrace_start_up && ref) {
2092 int failed = __ftrace_replace_code(p, 1);
2094 ftrace_bug(failed, p->ip);
2099 ftrace_new_pgs = NULL;
2101 stop = ftrace_now(raw_smp_processor_id());
2102 ftrace_update_time = stop - start;
2103 ftrace_update_tot_cnt += ftrace_update_cnt;
2108 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2113 if (WARN_ON(!count))
2116 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2119 * We want to fill as much as possible. No more than a page
2122 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2126 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2129 /* if we can't allocate this size, try something smaller */
2136 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2145 static struct ftrace_page *
2146 ftrace_allocate_pages(unsigned long num_to_init)
2148 struct ftrace_page *start_pg;
2149 struct ftrace_page *pg;
2156 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
2161 * Try to allocate as much as possible in one continues
2162 * location that fills in all of the space. We want to
2163 * waste as little space as possible.
2166 cnt = ftrace_allocate_records(pg, num_to_init);
2174 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
2185 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
2186 free_pages((unsigned long)pg->records, order);
2187 start_pg = pg->next;
2191 pr_info("ftrace: FAILED to allocate memory for functions\n");
2195 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
2200 pr_info("ftrace: No functions to be traced?\n");
2204 cnt = num_to_init / ENTRIES_PER_PAGE;
2205 pr_info("ftrace: allocating %ld entries in %d pages\n",
2206 num_to_init, cnt + 1);
2211 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
2213 struct ftrace_iterator {
2216 struct ftrace_page *pg;
2217 struct dyn_ftrace *func;
2218 struct ftrace_func_probe *probe;
2219 struct trace_parser parser;
2220 struct ftrace_hash *hash;
2221 struct ftrace_ops *ops;
2228 t_hash_next(struct seq_file *m, loff_t *pos)
2230 struct ftrace_iterator *iter = m->private;
2231 struct hlist_node *hnd = NULL;
2232 struct hlist_head *hhd;
2238 hnd = &iter->probe->node;
2240 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
2243 hhd = &ftrace_func_hash[iter->hidx];
2245 if (hlist_empty(hhd)) {
2261 if (WARN_ON_ONCE(!hnd))
2264 iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
2269 static void *t_hash_start(struct seq_file *m, loff_t *pos)
2271 struct ftrace_iterator *iter = m->private;
2275 if (!(iter->flags & FTRACE_ITER_DO_HASH))
2278 if (iter->func_pos > *pos)
2282 for (l = 0; l <= (*pos - iter->func_pos); ) {
2283 p = t_hash_next(m, &l);
2290 /* Only set this if we have an item */
2291 iter->flags |= FTRACE_ITER_HASH;
2297 t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
2299 struct ftrace_func_probe *rec;
2302 if (WARN_ON_ONCE(!rec))
2305 if (rec->ops->print)
2306 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
2308 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
2311 seq_printf(m, ":%p", rec->data);
2318 t_next(struct seq_file *m, void *v, loff_t *pos)
2320 struct ftrace_iterator *iter = m->private;
2321 struct ftrace_ops *ops = iter->ops;
2322 struct dyn_ftrace *rec = NULL;
2324 if (unlikely(ftrace_disabled))
2327 if (iter->flags & FTRACE_ITER_HASH)
2328 return t_hash_next(m, pos);
2331 iter->pos = iter->func_pos = *pos;
2333 if (iter->flags & FTRACE_ITER_PRINTALL)
2334 return t_hash_start(m, pos);
2337 if (iter->idx >= iter->pg->index) {
2338 if (iter->pg->next) {
2339 iter->pg = iter->pg->next;
2344 rec = &iter->pg->records[iter->idx++];
2345 if (((iter->flags & FTRACE_ITER_FILTER) &&
2346 !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||
2348 ((iter->flags & FTRACE_ITER_NOTRACE) &&
2349 !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
2351 ((iter->flags & FTRACE_ITER_ENABLED) &&
2352 !(rec->flags & ~FTRACE_FL_MASK))) {
2360 return t_hash_start(m, pos);
2367 static void reset_iter_read(struct ftrace_iterator *iter)
2371 iter->flags &= ~(FTRACE_ITER_PRINTALL & FTRACE_ITER_HASH);
2374 static void *t_start(struct seq_file *m, loff_t *pos)
2376 struct ftrace_iterator *iter = m->private;
2377 struct ftrace_ops *ops = iter->ops;
2381 mutex_lock(&ftrace_lock);
2383 if (unlikely(ftrace_disabled))
2387 * If an lseek was done, then reset and start from beginning.
2389 if (*pos < iter->pos)
2390 reset_iter_read(iter);
2393 * For set_ftrace_filter reading, if we have the filter
2394 * off, we can short cut and just print out that all
2395 * functions are enabled.
2397 if (iter->flags & FTRACE_ITER_FILTER &&
2398 ftrace_hash_empty(ops->filter_hash)) {
2400 return t_hash_start(m, pos);
2401 iter->flags |= FTRACE_ITER_PRINTALL;
2402 /* reset in case of seek/pread */
2403 iter->flags &= ~FTRACE_ITER_HASH;
2407 if (iter->flags & FTRACE_ITER_HASH)
2408 return t_hash_start(m, pos);
2411 * Unfortunately, we need to restart at ftrace_pages_start
2412 * every time we let go of the ftrace_mutex. This is because
2413 * those pointers can change without the lock.
2415 iter->pg = ftrace_pages_start;
2417 for (l = 0; l <= *pos; ) {
2418 p = t_next(m, p, &l);
2424 return t_hash_start(m, pos);
2429 static void t_stop(struct seq_file *m, void *p)
2431 mutex_unlock(&ftrace_lock);
2434 static int t_show(struct seq_file *m, void *v)
2436 struct ftrace_iterator *iter = m->private;
2437 struct dyn_ftrace *rec;
2439 if (iter->flags & FTRACE_ITER_HASH)
2440 return t_hash_show(m, iter);
2442 if (iter->flags & FTRACE_ITER_PRINTALL) {
2443 seq_printf(m, "#### all functions enabled ####\n");
2452 seq_printf(m, "%ps", (void *)rec->ip);
2453 if (iter->flags & FTRACE_ITER_ENABLED)
2454 seq_printf(m, " (%ld)",
2455 rec->flags & ~FTRACE_FL_MASK);
2456 seq_printf(m, "\n");
2461 static const struct seq_operations show_ftrace_seq_ops = {
2469 ftrace_avail_open(struct inode *inode, struct file *file)
2471 struct ftrace_iterator *iter;
2474 if (unlikely(ftrace_disabled))
2477 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2481 iter->pg = ftrace_pages_start;
2482 iter->ops = &global_ops;
2484 ret = seq_open(file, &show_ftrace_seq_ops);
2486 struct seq_file *m = file->private_data;
2497 ftrace_enabled_open(struct inode *inode, struct file *file)
2499 struct ftrace_iterator *iter;
2502 if (unlikely(ftrace_disabled))
2505 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2509 iter->pg = ftrace_pages_start;
2510 iter->flags = FTRACE_ITER_ENABLED;
2511 iter->ops = &global_ops;
2513 ret = seq_open(file, &show_ftrace_seq_ops);
2515 struct seq_file *m = file->private_data;
2525 static void ftrace_filter_reset(struct ftrace_hash *hash)
2527 mutex_lock(&ftrace_lock);
2528 ftrace_hash_clear(hash);
2529 mutex_unlock(&ftrace_lock);
2533 * ftrace_regex_open - initialize function tracer filter files
2534 * @ops: The ftrace_ops that hold the hash filters
2535 * @flag: The type of filter to process
2536 * @inode: The inode, usually passed in to your open routine
2537 * @file: The file, usually passed in to your open routine
2539 * ftrace_regex_open() initializes the filter files for the
2540 * @ops. Depending on @flag it may process the filter hash or
2541 * the notrace hash of @ops. With this called from the open
2542 * routine, you can use ftrace_filter_write() for the write
2543 * routine if @flag has FTRACE_ITER_FILTER set, or
2544 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
2545 * ftrace_regex_lseek() should be used as the lseek routine, and
2546 * release must call ftrace_regex_release().
2549 ftrace_regex_open(struct ftrace_ops *ops, int flag,
2550 struct inode *inode, struct file *file)
2552 struct ftrace_iterator *iter;
2553 struct ftrace_hash *hash;
2556 if (unlikely(ftrace_disabled))
2559 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2563 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
2568 if (flag & FTRACE_ITER_NOTRACE)
2569 hash = ops->notrace_hash;
2571 hash = ops->filter_hash;
2576 if (file->f_mode & FMODE_WRITE) {
2577 mutex_lock(&ftrace_lock);
2578 iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
2579 mutex_unlock(&ftrace_lock);
2582 trace_parser_put(&iter->parser);
2588 mutex_lock(&ftrace_regex_lock);
2590 if ((file->f_mode & FMODE_WRITE) &&
2591 (file->f_flags & O_TRUNC))
2592 ftrace_filter_reset(iter->hash);
2594 if (file->f_mode & FMODE_READ) {
2595 iter->pg = ftrace_pages_start;
2597 ret = seq_open(file, &show_ftrace_seq_ops);
2599 struct seq_file *m = file->private_data;
2603 free_ftrace_hash(iter->hash);
2604 trace_parser_put(&iter->parser);
2608 file->private_data = iter;
2609 mutex_unlock(&ftrace_regex_lock);
2615 ftrace_filter_open(struct inode *inode, struct file *file)
2617 return ftrace_regex_open(&global_ops,
2618 FTRACE_ITER_FILTER | FTRACE_ITER_DO_HASH,
2623 ftrace_notrace_open(struct inode *inode, struct file *file)
2625 return ftrace_regex_open(&global_ops, FTRACE_ITER_NOTRACE,
2630 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
2634 if (file->f_mode & FMODE_READ)
2635 ret = seq_lseek(file, offset, origin);
2637 file->f_pos = ret = 1;
2642 static int ftrace_match(char *str, char *regex, int len, int type)
2649 if (strcmp(str, regex) == 0)
2652 case MATCH_FRONT_ONLY:
2653 if (strncmp(str, regex, len) == 0)
2656 case MATCH_MIDDLE_ONLY:
2657 if (strstr(str, regex))
2660 case MATCH_END_ONLY:
2662 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
2671 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
2673 struct ftrace_func_entry *entry;
2676 entry = ftrace_lookup_ip(hash, rec->ip);
2678 /* Do nothing if it doesn't exist */
2682 free_hash_entry(hash, entry);
2684 /* Do nothing if it exists */
2688 ret = add_hash_entry(hash, rec->ip);
2694 ftrace_match_record(struct dyn_ftrace *rec, char *mod,
2695 char *regex, int len, int type)
2697 char str[KSYM_SYMBOL_LEN];
2700 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
2703 /* module lookup requires matching the module */
2704 if (!modname || strcmp(modname, mod))
2707 /* blank search means to match all funcs in the mod */
2712 return ftrace_match(str, regex, len, type);
2716 match_records(struct ftrace_hash *hash, char *buff,
2717 int len, char *mod, int not)
2719 unsigned search_len = 0;
2720 struct ftrace_page *pg;
2721 struct dyn_ftrace *rec;
2722 int type = MATCH_FULL;
2723 char *search = buff;
2728 type = filter_parse_regex(buff, len, &search, ¬);
2729 search_len = strlen(search);
2732 mutex_lock(&ftrace_lock);
2734 if (unlikely(ftrace_disabled))
2737 do_for_each_ftrace_rec(pg, rec) {
2738 if (ftrace_match_record(rec, mod, search, search_len, type)) {
2739 ret = enter_record(hash, rec, not);
2746 } while_for_each_ftrace_rec();
2748 mutex_unlock(&ftrace_lock);
2754 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
2756 return match_records(hash, buff, len, NULL, 0);
2760 ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
2764 /* blank or '*' mean the same */
2765 if (strcmp(buff, "*") == 0)
2768 /* handle the case of 'dont filter this module' */
2769 if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
2774 return match_records(hash, buff, strlen(buff), mod, not);
2778 * We register the module command as a template to show others how
2779 * to register the a command as well.
2783 ftrace_mod_callback(struct ftrace_hash *hash,
2784 char *func, char *cmd, char *param, int enable)
2790 * cmd == 'mod' because we only registered this func
2791 * for the 'mod' ftrace_func_command.
2792 * But if you register one func with multiple commands,
2793 * you can tell which command was used by the cmd
2797 /* we must have a module name */
2801 mod = strsep(¶m, ":");
2805 ret = ftrace_match_module_records(hash, func, mod);
2814 static struct ftrace_func_command ftrace_mod_cmd = {
2816 .func = ftrace_mod_callback,
2819 static int __init ftrace_mod_cmd_init(void)
2821 return register_ftrace_command(&ftrace_mod_cmd);
2823 device_initcall(ftrace_mod_cmd_init);
2826 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
2828 struct ftrace_func_probe *entry;
2829 struct hlist_head *hhd;
2830 struct hlist_node *n;
2833 key = hash_long(ip, FTRACE_HASH_BITS);
2835 hhd = &ftrace_func_hash[key];
2837 if (hlist_empty(hhd))
2841 * Disable preemption for these calls to prevent a RCU grace
2842 * period. This syncs the hash iteration and freeing of items
2843 * on the hash. rcu_read_lock is too dangerous here.
2845 preempt_disable_notrace();
2846 hlist_for_each_entry_rcu(entry, n, hhd, node) {
2847 if (entry->ip == ip)
2848 entry->ops->func(ip, parent_ip, &entry->data);
2850 preempt_enable_notrace();
2853 static struct ftrace_ops trace_probe_ops __read_mostly =
2855 .func = function_trace_probe_call,
2858 static int ftrace_probe_registered;
2860 static void __enable_ftrace_function_probe(void)
2865 if (ftrace_probe_registered)
2868 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2869 struct hlist_head *hhd = &ftrace_func_hash[i];
2873 /* Nothing registered? */
2874 if (i == FTRACE_FUNC_HASHSIZE)
2877 ret = __register_ftrace_function(&trace_probe_ops);
2879 ret = ftrace_startup(&trace_probe_ops, 0);
2881 ftrace_probe_registered = 1;
2884 static void __disable_ftrace_function_probe(void)
2889 if (!ftrace_probe_registered)
2892 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2893 struct hlist_head *hhd = &ftrace_func_hash[i];
2898 /* no more funcs left */
2899 ret = __unregister_ftrace_function(&trace_probe_ops);
2901 ftrace_shutdown(&trace_probe_ops, 0);
2903 ftrace_probe_registered = 0;
2907 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
2909 struct ftrace_func_probe *entry =
2910 container_of(rhp, struct ftrace_func_probe, rcu);
2912 if (entry->ops->free)
2913 entry->ops->free(&entry->data);
2919 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2922 struct ftrace_func_probe *entry;
2923 struct ftrace_page *pg;
2924 struct dyn_ftrace *rec;
2930 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
2931 len = strlen(search);
2933 /* we do not support '!' for function probes */
2937 mutex_lock(&ftrace_lock);
2939 if (unlikely(ftrace_disabled))
2942 do_for_each_ftrace_rec(pg, rec) {
2944 if (!ftrace_match_record(rec, NULL, search, len, type))
2947 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2949 /* If we did not process any, then return error */
2960 * The caller might want to do something special
2961 * for each function we find. We call the callback
2962 * to give the caller an opportunity to do so.
2964 if (ops->callback) {
2965 if (ops->callback(rec->ip, &entry->data) < 0) {
2966 /* caller does not like this func */
2973 entry->ip = rec->ip;
2975 key = hash_long(entry->ip, FTRACE_HASH_BITS);
2976 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
2978 } while_for_each_ftrace_rec();
2979 __enable_ftrace_function_probe();
2982 mutex_unlock(&ftrace_lock);
2988 PROBE_TEST_FUNC = 1,
2993 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2994 void *data, int flags)
2996 struct ftrace_func_probe *entry;
2997 struct hlist_node *n, *tmp;
2998 char str[KSYM_SYMBOL_LEN];
2999 int type = MATCH_FULL;
3003 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
3008 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
3009 len = strlen(search);
3011 /* we do not support '!' for function probes */
3016 mutex_lock(&ftrace_lock);
3017 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3018 struct hlist_head *hhd = &ftrace_func_hash[i];
3020 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
3022 /* break up if statements for readability */
3023 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
3026 if ((flags & PROBE_TEST_DATA) && entry->data != data)
3029 /* do this last, since it is the most expensive */
3031 kallsyms_lookup(entry->ip, NULL, NULL,
3033 if (!ftrace_match(str, glob, len, type))
3037 hlist_del(&entry->node);
3038 call_rcu(&entry->rcu, ftrace_free_entry_rcu);
3041 __disable_ftrace_function_probe();
3042 mutex_unlock(&ftrace_lock);
3046 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3049 __unregister_ftrace_function_probe(glob, ops, data,
3050 PROBE_TEST_FUNC | PROBE_TEST_DATA);
3054 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
3056 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
3059 void unregister_ftrace_function_probe_all(char *glob)
3061 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
3064 static LIST_HEAD(ftrace_commands);
3065 static DEFINE_MUTEX(ftrace_cmd_mutex);
3067 int register_ftrace_command(struct ftrace_func_command *cmd)
3069 struct ftrace_func_command *p;
3072 mutex_lock(&ftrace_cmd_mutex);
3073 list_for_each_entry(p, &ftrace_commands, list) {
3074 if (strcmp(cmd->name, p->name) == 0) {
3079 list_add(&cmd->list, &ftrace_commands);
3081 mutex_unlock(&ftrace_cmd_mutex);
3086 int unregister_ftrace_command(struct ftrace_func_command *cmd)
3088 struct ftrace_func_command *p, *n;
3091 mutex_lock(&ftrace_cmd_mutex);
3092 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
3093 if (strcmp(cmd->name, p->name) == 0) {
3095 list_del_init(&p->list);
3100 mutex_unlock(&ftrace_cmd_mutex);
3105 static int ftrace_process_regex(struct ftrace_hash *hash,
3106 char *buff, int len, int enable)
3108 char *func, *command, *next = buff;
3109 struct ftrace_func_command *p;
3112 func = strsep(&next, ":");
3115 ret = ftrace_match_records(hash, func, len);
3125 command = strsep(&next, ":");
3127 mutex_lock(&ftrace_cmd_mutex);
3128 list_for_each_entry(p, &ftrace_commands, list) {
3129 if (strcmp(p->name, command) == 0) {
3130 ret = p->func(hash, func, command, next, enable);
3135 mutex_unlock(&ftrace_cmd_mutex);
3141 ftrace_regex_write(struct file *file, const char __user *ubuf,
3142 size_t cnt, loff_t *ppos, int enable)
3144 struct ftrace_iterator *iter;
3145 struct trace_parser *parser;
3151 mutex_lock(&ftrace_regex_lock);
3154 if (unlikely(ftrace_disabled))
3157 if (file->f_mode & FMODE_READ) {
3158 struct seq_file *m = file->private_data;
3161 iter = file->private_data;
3163 parser = &iter->parser;
3164 read = trace_get_user(parser, ubuf, cnt, ppos);
3166 if (read >= 0 && trace_parser_loaded(parser) &&
3167 !trace_parser_cont(parser)) {
3168 ret = ftrace_process_regex(iter->hash, parser->buffer,
3169 parser->idx, enable);
3170 trace_parser_clear(parser);
3177 mutex_unlock(&ftrace_regex_lock);
3183 ftrace_filter_write(struct file *file, const char __user *ubuf,
3184 size_t cnt, loff_t *ppos)
3186 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
3190 ftrace_notrace_write(struct file *file, const char __user *ubuf,
3191 size_t cnt, loff_t *ppos)
3193 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
3197 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
3198 int reset, int enable)
3200 struct ftrace_hash **orig_hash;
3201 struct ftrace_hash *hash;
3204 /* All global ops uses the global ops filters */
3205 if (ops->flags & FTRACE_OPS_FL_GLOBAL)
3208 if (unlikely(ftrace_disabled))
3212 orig_hash = &ops->filter_hash;
3214 orig_hash = &ops->notrace_hash;
3216 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3220 mutex_lock(&ftrace_regex_lock);
3222 ftrace_filter_reset(hash);
3223 if (buf && !ftrace_match_records(hash, buf, len)) {
3225 goto out_regex_unlock;
3228 mutex_lock(&ftrace_lock);
3229 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3230 if (!ret && ops->flags & FTRACE_OPS_FL_ENABLED
3232 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3234 mutex_unlock(&ftrace_lock);
3237 mutex_unlock(&ftrace_regex_lock);
3239 free_ftrace_hash(hash);
3244 * ftrace_set_filter - set a function to filter on in ftrace
3245 * @ops - the ops to set the filter with
3246 * @buf - the string that holds the function filter text.
3247 * @len - the length of the string.
3248 * @reset - non zero to reset all filters before applying this filter.
3250 * Filters denote which functions should be enabled when tracing is enabled.
3251 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3253 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
3256 return ftrace_set_regex(ops, buf, len, reset, 1);
3258 EXPORT_SYMBOL_GPL(ftrace_set_filter);
3261 * ftrace_set_notrace - set a function to not trace in ftrace
3262 * @ops - the ops to set the notrace filter with
3263 * @buf - the string that holds the function notrace text.
3264 * @len - the length of the string.
3265 * @reset - non zero to reset all filters before applying this filter.
3267 * Notrace Filters denote which functions should not be enabled when tracing
3268 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3271 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
3274 return ftrace_set_regex(ops, buf, len, reset, 0);
3276 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
3278 * ftrace_set_filter - set a function to filter on in ftrace
3279 * @ops - the ops to set the filter with
3280 * @buf - the string that holds the function filter text.
3281 * @len - the length of the string.
3282 * @reset - non zero to reset all filters before applying this filter.
3284 * Filters denote which functions should be enabled when tracing is enabled.
3285 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3287 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
3289 ftrace_set_regex(&global_ops, buf, len, reset, 1);
3291 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
3294 * ftrace_set_notrace - set a function to not trace in ftrace
3295 * @ops - the ops to set the notrace filter with
3296 * @buf - the string that holds the function notrace text.
3297 * @len - the length of the string.
3298 * @reset - non zero to reset all filters before applying this filter.
3300 * Notrace Filters denote which functions should not be enabled when tracing
3301 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3304 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
3306 ftrace_set_regex(&global_ops, buf, len, reset, 0);
3308 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
3311 * command line interface to allow users to set filters on boot up.
3313 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
3314 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
3315 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
3317 static int __init set_ftrace_notrace(char *str)
3319 strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
3322 __setup("ftrace_notrace=", set_ftrace_notrace);
3324 static int __init set_ftrace_filter(char *str)
3326 strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
3329 __setup("ftrace_filter=", set_ftrace_filter);
3331 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3332 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
3333 static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
3335 static int __init set_graph_function(char *str)
3337 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
3340 __setup("ftrace_graph_filter=", set_graph_function);
3342 static void __init set_ftrace_early_graph(char *buf)
3348 func = strsep(&buf, ",");
3349 /* we allow only one expression at a time */
3350 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3353 printk(KERN_DEBUG "ftrace: function %s not "
3354 "traceable\n", func);
3357 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3360 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
3365 func = strsep(&buf, ",");
3366 ftrace_set_regex(ops, func, strlen(func), 0, enable);
3370 static void __init set_ftrace_early_filters(void)
3372 if (ftrace_filter_buf[0])
3373 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
3374 if (ftrace_notrace_buf[0])
3375 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
3376 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3377 if (ftrace_graph_buf[0])
3378 set_ftrace_early_graph(ftrace_graph_buf);
3379 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3382 int ftrace_regex_release(struct inode *inode, struct file *file)
3384 struct seq_file *m = (struct seq_file *)file->private_data;
3385 struct ftrace_iterator *iter;
3386 struct ftrace_hash **orig_hash;
3387 struct trace_parser *parser;
3391 mutex_lock(&ftrace_regex_lock);
3392 if (file->f_mode & FMODE_READ) {
3395 seq_release(inode, file);
3397 iter = file->private_data;
3399 parser = &iter->parser;
3400 if (trace_parser_loaded(parser)) {
3401 parser->buffer[parser->idx] = 0;
3402 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
3405 trace_parser_put(parser);
3407 if (file->f_mode & FMODE_WRITE) {
3408 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
3411 orig_hash = &iter->ops->filter_hash;
3413 orig_hash = &iter->ops->notrace_hash;
3415 mutex_lock(&ftrace_lock);
3416 ret = ftrace_hash_move(iter->ops, filter_hash,
3417 orig_hash, iter->hash);
3418 if (!ret && (iter->ops->flags & FTRACE_OPS_FL_ENABLED)
3420 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3422 mutex_unlock(&ftrace_lock);
3424 free_ftrace_hash(iter->hash);
3427 mutex_unlock(&ftrace_regex_lock);
3431 static const struct file_operations ftrace_avail_fops = {
3432 .open = ftrace_avail_open,
3434 .llseek = seq_lseek,
3435 .release = seq_release_private,
3438 static const struct file_operations ftrace_enabled_fops = {
3439 .open = ftrace_enabled_open,
3441 .llseek = seq_lseek,
3442 .release = seq_release_private,
3445 static const struct file_operations ftrace_filter_fops = {
3446 .open = ftrace_filter_open,
3448 .write = ftrace_filter_write,
3449 .llseek = ftrace_regex_lseek,
3450 .release = ftrace_regex_release,
3453 static const struct file_operations ftrace_notrace_fops = {
3454 .open = ftrace_notrace_open,
3456 .write = ftrace_notrace_write,
3457 .llseek = ftrace_regex_lseek,
3458 .release = ftrace_regex_release,
3461 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3463 static DEFINE_MUTEX(graph_lock);
3465 int ftrace_graph_count;
3466 int ftrace_graph_filter_enabled;
3467 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
3470 __g_next(struct seq_file *m, loff_t *pos)
3472 if (*pos >= ftrace_graph_count)
3474 return &ftrace_graph_funcs[*pos];
3478 g_next(struct seq_file *m, void *v, loff_t *pos)
3481 return __g_next(m, pos);
3484 static void *g_start(struct seq_file *m, loff_t *pos)
3486 mutex_lock(&graph_lock);
3488 /* Nothing, tell g_show to print all functions are enabled */
3489 if (!ftrace_graph_filter_enabled && !*pos)
3492 return __g_next(m, pos);
3495 static void g_stop(struct seq_file *m, void *p)
3497 mutex_unlock(&graph_lock);
3500 static int g_show(struct seq_file *m, void *v)
3502 unsigned long *ptr = v;
3507 if (ptr == (unsigned long *)1) {
3508 seq_printf(m, "#### all functions enabled ####\n");
3512 seq_printf(m, "%ps\n", (void *)*ptr);
3517 static const struct seq_operations ftrace_graph_seq_ops = {
3525 ftrace_graph_open(struct inode *inode, struct file *file)
3529 if (unlikely(ftrace_disabled))
3532 mutex_lock(&graph_lock);
3533 if ((file->f_mode & FMODE_WRITE) &&
3534 (file->f_flags & O_TRUNC)) {
3535 ftrace_graph_filter_enabled = 0;
3536 ftrace_graph_count = 0;
3537 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
3539 mutex_unlock(&graph_lock);
3541 if (file->f_mode & FMODE_READ)
3542 ret = seq_open(file, &ftrace_graph_seq_ops);
3548 ftrace_graph_release(struct inode *inode, struct file *file)
3550 if (file->f_mode & FMODE_READ)
3551 seq_release(inode, file);
3556 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
3558 struct dyn_ftrace *rec;
3559 struct ftrace_page *pg;
3568 type = filter_parse_regex(buffer, strlen(buffer), &search, ¬);
3569 if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
3572 search_len = strlen(search);
3574 mutex_lock(&ftrace_lock);
3576 if (unlikely(ftrace_disabled)) {
3577 mutex_unlock(&ftrace_lock);
3581 do_for_each_ftrace_rec(pg, rec) {
3583 if (ftrace_match_record(rec, NULL, search, search_len, type)) {
3584 /* if it is in the array */
3586 for (i = 0; i < *idx; i++) {
3587 if (array[i] == rec->ip) {
3596 array[(*idx)++] = rec->ip;
3597 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
3602 array[i] = array[--(*idx)];
3608 } while_for_each_ftrace_rec();
3610 mutex_unlock(&ftrace_lock);
3615 ftrace_graph_filter_enabled = 1;
3620 ftrace_graph_write(struct file *file, const char __user *ubuf,
3621 size_t cnt, loff_t *ppos)
3623 struct trace_parser parser;
3629 mutex_lock(&graph_lock);
3631 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
3636 read = trace_get_user(&parser, ubuf, cnt, ppos);
3638 if (read >= 0 && trace_parser_loaded((&parser))) {
3639 parser.buffer[parser.idx] = 0;
3641 /* we allow only one expression at a time */
3642 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3651 trace_parser_put(&parser);
3653 mutex_unlock(&graph_lock);
3658 static const struct file_operations ftrace_graph_fops = {
3659 .open = ftrace_graph_open,
3661 .write = ftrace_graph_write,
3662 .release = ftrace_graph_release,
3663 .llseek = seq_lseek,
3665 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3667 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
3670 trace_create_file("available_filter_functions", 0444,
3671 d_tracer, NULL, &ftrace_avail_fops);
3673 trace_create_file("enabled_functions", 0444,
3674 d_tracer, NULL, &ftrace_enabled_fops);
3676 trace_create_file("set_ftrace_filter", 0644, d_tracer,
3677 NULL, &ftrace_filter_fops);
3679 trace_create_file("set_ftrace_notrace", 0644, d_tracer,
3680 NULL, &ftrace_notrace_fops);
3682 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3683 trace_create_file("set_graph_function", 0444, d_tracer,
3685 &ftrace_graph_fops);
3686 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3691 static void ftrace_swap_recs(void *a, void *b, int size)
3693 struct dyn_ftrace *reca = a;
3694 struct dyn_ftrace *recb = b;
3695 struct dyn_ftrace t;
3702 static int ftrace_process_locs(struct module *mod,
3703 unsigned long *start,
3706 struct ftrace_page *pg;
3707 unsigned long count;
3710 unsigned long flags = 0; /* Shut up gcc */
3713 count = end - start;
3718 pg = ftrace_allocate_pages(count);
3722 mutex_lock(&ftrace_lock);
3725 * Core and each module needs their own pages, as
3726 * modules will free them when they are removed.
3727 * Force a new page to be allocated for modules.
3730 WARN_ON(ftrace_pages || ftrace_pages_start);
3731 /* First initialization */
3732 ftrace_pages = ftrace_pages_start = pg;
3737 if (WARN_ON(ftrace_pages->next)) {
3738 /* Hmm, we have free pages? */
3739 while (ftrace_pages->next)
3740 ftrace_pages = ftrace_pages->next;
3743 ftrace_pages->next = pg;
3749 addr = ftrace_call_adjust(*p++);
3751 * Some architecture linkers will pad between
3752 * the different mcount_loc sections of different
3753 * object files to satisfy alignments.
3754 * Skip any NULL pointers.
3758 if (!ftrace_record_ip(addr))
3762 /* These new locations need to be initialized */
3763 ftrace_new_pgs = pg;
3765 /* Make each individual set of pages sorted by ips */
3766 for (; pg; pg = pg->next)
3767 sort(pg->records, pg->index, sizeof(struct dyn_ftrace),
3768 ftrace_cmp_recs, ftrace_swap_recs);
3771 * We only need to disable interrupts on start up
3772 * because we are modifying code that an interrupt
3773 * may execute, and the modification is not atomic.
3774 * But for modules, nothing runs the code we modify
3775 * until we are finished with it, and there's no
3776 * reason to cause large interrupt latencies while we do it.
3779 local_irq_save(flags);
3780 ftrace_update_code(mod);
3782 local_irq_restore(flags);
3785 mutex_unlock(&ftrace_lock);
3790 #ifdef CONFIG_MODULES
3792 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
3794 void ftrace_release_mod(struct module *mod)
3796 struct dyn_ftrace *rec;
3797 struct ftrace_page **last_pg;
3798 struct ftrace_page *pg;
3801 mutex_lock(&ftrace_lock);
3803 if (ftrace_disabled)
3807 * Each module has its own ftrace_pages, remove
3808 * them from the list.
3810 last_pg = &ftrace_pages_start;
3811 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
3812 rec = &pg->records[0];
3813 if (within_module_core(rec->ip, mod)) {
3815 * As core pages are first, the first
3816 * page should never be a module page.
3818 if (WARN_ON(pg == ftrace_pages_start))
3821 /* Check if we are deleting the last page */
3822 if (pg == ftrace_pages)
3823 ftrace_pages = next_to_ftrace_page(last_pg);
3825 *last_pg = pg->next;
3826 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3827 free_pages((unsigned long)pg->records, order);
3830 last_pg = &pg->next;
3833 mutex_unlock(&ftrace_lock);
3836 static void ftrace_init_module(struct module *mod,
3837 unsigned long *start, unsigned long *end)
3839 if (ftrace_disabled || start == end)
3841 ftrace_process_locs(mod, start, end);
3844 static int ftrace_module_notify(struct notifier_block *self,
3845 unsigned long val, void *data)
3847 struct module *mod = data;
3850 case MODULE_STATE_COMING:
3851 ftrace_init_module(mod, mod->ftrace_callsites,
3852 mod->ftrace_callsites +
3853 mod->num_ftrace_callsites);
3855 case MODULE_STATE_GOING:
3856 ftrace_release_mod(mod);
3863 static int ftrace_module_notify(struct notifier_block *self,
3864 unsigned long val, void *data)
3868 #endif /* CONFIG_MODULES */
3870 struct notifier_block ftrace_module_nb = {
3871 .notifier_call = ftrace_module_notify,
3875 extern unsigned long __start_mcount_loc[];
3876 extern unsigned long __stop_mcount_loc[];
3878 void __init ftrace_init(void)
3880 unsigned long count, addr, flags;
3883 /* Keep the ftrace pointer to the stub */
3884 addr = (unsigned long)ftrace_stub;
3886 local_irq_save(flags);
3887 ftrace_dyn_arch_init(&addr);
3888 local_irq_restore(flags);
3890 /* ftrace_dyn_arch_init places the return code in addr */
3894 count = __stop_mcount_loc - __start_mcount_loc;
3896 ret = ftrace_dyn_table_alloc(count);
3900 last_ftrace_enabled = ftrace_enabled = 1;
3902 ret = ftrace_process_locs(NULL,
3906 ret = register_module_notifier(&ftrace_module_nb);
3908 pr_warning("Failed to register trace ftrace module notifier\n");
3910 set_ftrace_early_filters();
3914 ftrace_disabled = 1;
3919 static struct ftrace_ops global_ops = {
3920 .func = ftrace_stub,
3923 static int __init ftrace_nodyn_init(void)
3928 device_initcall(ftrace_nodyn_init);
3930 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
3931 static inline void ftrace_startup_enable(int command) { }
3932 /* Keep as macros so we do not need to define the commands */
3933 # define ftrace_startup(ops, command) \
3935 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
3938 # define ftrace_shutdown(ops, command) do { } while (0)
3939 # define ftrace_startup_sysctl() do { } while (0)
3940 # define ftrace_shutdown_sysctl() do { } while (0)
3943 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
3948 #endif /* CONFIG_DYNAMIC_FTRACE */
3951 ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip)
3953 struct ftrace_ops *op;
3955 if (unlikely(trace_recursion_test(TRACE_CONTROL_BIT)))
3959 * Some of the ops may be dynamically allocated,
3960 * they must be freed after a synchronize_sched().
3962 preempt_disable_notrace();
3963 trace_recursion_set(TRACE_CONTROL_BIT);
3964 op = rcu_dereference_raw(ftrace_control_list);
3965 while (op != &ftrace_list_end) {
3966 if (!ftrace_function_local_disabled(op) &&
3967 ftrace_ops_test(op, ip))
3968 op->func(ip, parent_ip);
3970 op = rcu_dereference_raw(op->next);
3972 trace_recursion_clear(TRACE_CONTROL_BIT);
3973 preempt_enable_notrace();
3976 static struct ftrace_ops control_ops = {
3977 .func = ftrace_ops_control_func,
3981 ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
3983 struct ftrace_ops *op;
3985 if (unlikely(trace_recursion_test(TRACE_INTERNAL_BIT)))
3988 trace_recursion_set(TRACE_INTERNAL_BIT);
3990 * Some of the ops may be dynamically allocated,
3991 * they must be freed after a synchronize_sched().
3993 preempt_disable_notrace();
3994 op = rcu_dereference_raw(ftrace_ops_list);
3995 while (op != &ftrace_list_end) {
3996 if (ftrace_ops_test(op, ip))
3997 op->func(ip, parent_ip);
3998 op = rcu_dereference_raw(op->next);
4000 preempt_enable_notrace();
4001 trace_recursion_clear(TRACE_INTERNAL_BIT);
4004 static void clear_ftrace_swapper(void)
4006 struct task_struct *p;
4010 for_each_online_cpu(cpu) {
4012 clear_tsk_trace_trace(p);
4017 static void set_ftrace_swapper(void)
4019 struct task_struct *p;
4023 for_each_online_cpu(cpu) {
4025 set_tsk_trace_trace(p);
4030 static void clear_ftrace_pid(struct pid *pid)
4032 struct task_struct *p;
4035 do_each_pid_task(pid, PIDTYPE_PID, p) {
4036 clear_tsk_trace_trace(p);
4037 } while_each_pid_task(pid, PIDTYPE_PID, p);
4043 static void set_ftrace_pid(struct pid *pid)
4045 struct task_struct *p;
4048 do_each_pid_task(pid, PIDTYPE_PID, p) {
4049 set_tsk_trace_trace(p);
4050 } while_each_pid_task(pid, PIDTYPE_PID, p);
4054 static void clear_ftrace_pid_task(struct pid *pid)
4056 if (pid == ftrace_swapper_pid)
4057 clear_ftrace_swapper();
4059 clear_ftrace_pid(pid);
4062 static void set_ftrace_pid_task(struct pid *pid)
4064 if (pid == ftrace_swapper_pid)
4065 set_ftrace_swapper();
4067 set_ftrace_pid(pid);
4070 static int ftrace_pid_add(int p)
4073 struct ftrace_pid *fpid;
4076 mutex_lock(&ftrace_lock);
4079 pid = ftrace_swapper_pid;
4081 pid = find_get_pid(p);
4088 list_for_each_entry(fpid, &ftrace_pids, list)
4089 if (fpid->pid == pid)
4094 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
4098 list_add(&fpid->list, &ftrace_pids);
4101 set_ftrace_pid_task(pid);
4103 ftrace_update_pid_func();
4104 ftrace_startup_enable(0);
4106 mutex_unlock(&ftrace_lock);
4110 if (pid != ftrace_swapper_pid)
4114 mutex_unlock(&ftrace_lock);
4118 static void ftrace_pid_reset(void)
4120 struct ftrace_pid *fpid, *safe;
4122 mutex_lock(&ftrace_lock);
4123 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
4124 struct pid *pid = fpid->pid;
4126 clear_ftrace_pid_task(pid);
4128 list_del(&fpid->list);
4132 ftrace_update_pid_func();
4133 ftrace_startup_enable(0);
4135 mutex_unlock(&ftrace_lock);
4138 static void *fpid_start(struct seq_file *m, loff_t *pos)
4140 mutex_lock(&ftrace_lock);
4142 if (list_empty(&ftrace_pids) && (!*pos))
4145 return seq_list_start(&ftrace_pids, *pos);
4148 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
4153 return seq_list_next(v, &ftrace_pids, pos);
4156 static void fpid_stop(struct seq_file *m, void *p)
4158 mutex_unlock(&ftrace_lock);
4161 static int fpid_show(struct seq_file *m, void *v)
4163 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
4165 if (v == (void *)1) {
4166 seq_printf(m, "no pid\n");
4170 if (fpid->pid == ftrace_swapper_pid)
4171 seq_printf(m, "swapper tasks\n");
4173 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
4178 static const struct seq_operations ftrace_pid_sops = {
4179 .start = fpid_start,
4186 ftrace_pid_open(struct inode *inode, struct file *file)
4190 if ((file->f_mode & FMODE_WRITE) &&
4191 (file->f_flags & O_TRUNC))
4194 if (file->f_mode & FMODE_READ)
4195 ret = seq_open(file, &ftrace_pid_sops);
4201 ftrace_pid_write(struct file *filp, const char __user *ubuf,
4202 size_t cnt, loff_t *ppos)
4208 if (cnt >= sizeof(buf))
4211 if (copy_from_user(&buf, ubuf, cnt))
4217 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
4218 * to clean the filter quietly.
4220 tmp = strstrip(buf);
4221 if (strlen(tmp) == 0)
4224 ret = strict_strtol(tmp, 10, &val);
4228 ret = ftrace_pid_add(val);
4230 return ret ? ret : cnt;
4234 ftrace_pid_release(struct inode *inode, struct file *file)
4236 if (file->f_mode & FMODE_READ)
4237 seq_release(inode, file);
4242 static const struct file_operations ftrace_pid_fops = {
4243 .open = ftrace_pid_open,
4244 .write = ftrace_pid_write,
4246 .llseek = seq_lseek,
4247 .release = ftrace_pid_release,
4250 static __init int ftrace_init_debugfs(void)
4252 struct dentry *d_tracer;
4254 d_tracer = tracing_init_dentry();
4258 ftrace_init_dyn_debugfs(d_tracer);
4260 trace_create_file("set_ftrace_pid", 0644, d_tracer,
4261 NULL, &ftrace_pid_fops);
4263 ftrace_profile_debugfs(d_tracer);
4267 fs_initcall(ftrace_init_debugfs);
4270 * ftrace_kill - kill ftrace
4272 * This function should be used by panic code. It stops ftrace
4273 * but in a not so nice way. If you need to simply kill ftrace
4274 * from a non-atomic section, use ftrace_kill.
4276 void ftrace_kill(void)
4278 ftrace_disabled = 1;
4280 clear_ftrace_function();
4284 * Test if ftrace is dead or not.
4286 int ftrace_is_dead(void)
4288 return ftrace_disabled;
4292 * register_ftrace_function - register a function for profiling
4293 * @ops - ops structure that holds the function for profiling.
4295 * Register a function to be called by all functions in the
4298 * Note: @ops->func and all the functions it calls must be labeled
4299 * with "notrace", otherwise it will go into a
4302 int register_ftrace_function(struct ftrace_ops *ops)
4306 mutex_lock(&ftrace_lock);
4308 if (unlikely(ftrace_disabled))
4311 ret = __register_ftrace_function(ops);
4313 ret = ftrace_startup(ops, 0);
4317 mutex_unlock(&ftrace_lock);
4320 EXPORT_SYMBOL_GPL(register_ftrace_function);
4323 * unregister_ftrace_function - unregister a function for profiling.
4324 * @ops - ops structure that holds the function to unregister
4326 * Unregister a function that was added to be called by ftrace profiling.
4328 int unregister_ftrace_function(struct ftrace_ops *ops)
4332 mutex_lock(&ftrace_lock);
4333 ret = __unregister_ftrace_function(ops);
4335 ftrace_shutdown(ops, 0);
4336 mutex_unlock(&ftrace_lock);
4340 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
4343 ftrace_enable_sysctl(struct ctl_table *table, int write,
4344 void __user *buffer, size_t *lenp,
4349 mutex_lock(&ftrace_lock);
4351 if (unlikely(ftrace_disabled))
4354 ret = proc_dointvec(table, write, buffer, lenp, ppos);
4356 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
4359 last_ftrace_enabled = !!ftrace_enabled;
4361 if (ftrace_enabled) {
4363 ftrace_startup_sysctl();
4365 /* we are starting ftrace again */
4366 if (ftrace_ops_list != &ftrace_list_end) {
4367 if (ftrace_ops_list->next == &ftrace_list_end)
4368 ftrace_trace_function = ftrace_ops_list->func;
4370 ftrace_trace_function = ftrace_ops_list_func;
4374 /* stopping ftrace calls (just send to ftrace_stub) */
4375 ftrace_trace_function = ftrace_stub;
4377 ftrace_shutdown_sysctl();
4381 mutex_unlock(&ftrace_lock);
4385 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4387 static int ftrace_graph_active;
4388 static struct notifier_block ftrace_suspend_notifier;
4390 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
4395 /* The callbacks that hook a function */
4396 trace_func_graph_ret_t ftrace_graph_return =
4397 (trace_func_graph_ret_t)ftrace_stub;
4398 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
4400 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
4401 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
4405 unsigned long flags;
4406 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
4407 struct task_struct *g, *t;
4409 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
4410 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
4411 * sizeof(struct ftrace_ret_stack),
4413 if (!ret_stack_list[i]) {
4421 read_lock_irqsave(&tasklist_lock, flags);
4422 do_each_thread(g, t) {
4428 if (t->ret_stack == NULL) {
4429 atomic_set(&t->tracing_graph_pause, 0);
4430 atomic_set(&t->trace_overrun, 0);
4431 t->curr_ret_stack = -1;
4432 /* Make sure the tasks see the -1 first: */
4434 t->ret_stack = ret_stack_list[start++];
4436 } while_each_thread(g, t);
4439 read_unlock_irqrestore(&tasklist_lock, flags);
4441 for (i = start; i < end; i++)
4442 kfree(ret_stack_list[i]);
4447 ftrace_graph_probe_sched_switch(void *ignore,
4448 struct task_struct *prev, struct task_struct *next)
4450 unsigned long long timestamp;
4454 * Does the user want to count the time a function was asleep.
4455 * If so, do not update the time stamps.
4457 if (trace_flags & TRACE_ITER_SLEEP_TIME)
4460 timestamp = trace_clock_local();
4462 prev->ftrace_timestamp = timestamp;
4464 /* only process tasks that we timestamped */
4465 if (!next->ftrace_timestamp)
4469 * Update all the counters in next to make up for the
4470 * time next was sleeping.
4472 timestamp -= next->ftrace_timestamp;
4474 for (index = next->curr_ret_stack; index >= 0; index--)
4475 next->ret_stack[index].calltime += timestamp;
4478 /* Allocate a return stack for each task */
4479 static int start_graph_tracing(void)
4481 struct ftrace_ret_stack **ret_stack_list;
4484 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
4485 sizeof(struct ftrace_ret_stack *),
4488 if (!ret_stack_list)
4491 /* The cpu_boot init_task->ret_stack will never be freed */
4492 for_each_online_cpu(cpu) {
4493 if (!idle_task(cpu)->ret_stack)
4494 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
4498 ret = alloc_retstack_tasklist(ret_stack_list);
4499 } while (ret == -EAGAIN);
4502 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4504 pr_info("ftrace_graph: Couldn't activate tracepoint"
4505 " probe to kernel_sched_switch\n");
4508 kfree(ret_stack_list);
4513 * Hibernation protection.
4514 * The state of the current task is too much unstable during
4515 * suspend/restore to disk. We want to protect against that.
4518 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
4522 case PM_HIBERNATION_PREPARE:
4523 pause_graph_tracing();
4526 case PM_POST_HIBERNATION:
4527 unpause_graph_tracing();
4533 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
4534 trace_func_graph_ent_t entryfunc)
4538 mutex_lock(&ftrace_lock);
4540 /* we currently allow only one tracer registered at a time */
4541 if (ftrace_graph_active) {
4546 ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
4547 register_pm_notifier(&ftrace_suspend_notifier);
4549 ftrace_graph_active++;
4550 ret = start_graph_tracing();
4552 ftrace_graph_active--;
4556 ftrace_graph_return = retfunc;
4557 ftrace_graph_entry = entryfunc;
4559 ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET);
4562 mutex_unlock(&ftrace_lock);
4566 void unregister_ftrace_graph(void)
4568 mutex_lock(&ftrace_lock);
4570 if (unlikely(!ftrace_graph_active))
4573 ftrace_graph_active--;
4574 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
4575 ftrace_graph_entry = ftrace_graph_entry_stub;
4576 ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET);
4577 unregister_pm_notifier(&ftrace_suspend_notifier);
4578 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4581 mutex_unlock(&ftrace_lock);
4584 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
4587 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
4589 atomic_set(&t->tracing_graph_pause, 0);
4590 atomic_set(&t->trace_overrun, 0);
4591 t->ftrace_timestamp = 0;
4592 /* make curr_ret_stack visible before we add the ret_stack */
4594 t->ret_stack = ret_stack;
4598 * Allocate a return stack for the idle task. May be the first
4599 * time through, or it may be done by CPU hotplug online.
4601 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
4603 t->curr_ret_stack = -1;
4605 * The idle task has no parent, it either has its own
4606 * stack or no stack at all.
4609 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
4611 if (ftrace_graph_active) {
4612 struct ftrace_ret_stack *ret_stack;
4614 ret_stack = per_cpu(idle_ret_stack, cpu);
4616 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4617 * sizeof(struct ftrace_ret_stack),
4621 per_cpu(idle_ret_stack, cpu) = ret_stack;
4623 graph_init_task(t, ret_stack);
4627 /* Allocate a return stack for newly created task */
4628 void ftrace_graph_init_task(struct task_struct *t)
4630 /* Make sure we do not use the parent ret_stack */
4631 t->ret_stack = NULL;
4632 t->curr_ret_stack = -1;
4634 if (ftrace_graph_active) {
4635 struct ftrace_ret_stack *ret_stack;
4637 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4638 * sizeof(struct ftrace_ret_stack),
4642 graph_init_task(t, ret_stack);
4646 void ftrace_graph_exit_task(struct task_struct *t)
4648 struct ftrace_ret_stack *ret_stack = t->ret_stack;
4650 t->ret_stack = NULL;
4651 /* NULL must become visible to IRQs before we free it: */
4657 void ftrace_graph_stop(void)