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/module.h>
26 #include <linux/ftrace.h>
27 #include <linux/sysctl.h>
28 #include <linux/slab.h>
29 #include <linux/ctype.h>
30 #include <linux/list.h>
31 #include <linux/hash.h>
32 #include <linux/rcupdate.h>
34 #include <trace/events/sched.h>
36 #include <asm/setup.h>
38 #include "trace_output.h"
39 #include "trace_stat.h"
41 #define FTRACE_WARN_ON(cond) \
49 #define FTRACE_WARN_ON_ONCE(cond) \
52 if (WARN_ON_ONCE(___r)) \
57 /* hash bits for specific function selection */
58 #define FTRACE_HASH_BITS 7
59 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
60 #define FTRACE_HASH_DEFAULT_BITS 10
61 #define FTRACE_HASH_MAX_BITS 12
63 /* ftrace_enabled is a method to turn ftrace on or off */
64 int ftrace_enabled __read_mostly;
65 static int last_ftrace_enabled;
67 /* Quick disabling of function tracer. */
68 int function_trace_stop;
70 /* List for set_ftrace_pid's pids. */
71 LIST_HEAD(ftrace_pids);
73 struct list_head list;
78 * ftrace_disabled is set when an anomaly is discovered.
79 * ftrace_disabled is much stronger than ftrace_enabled.
81 static int ftrace_disabled __read_mostly;
83 static DEFINE_MUTEX(ftrace_lock);
85 static struct ftrace_ops ftrace_list_end __read_mostly = {
89 static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end;
90 static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
91 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
92 static ftrace_func_t __ftrace_trace_function_delay __read_mostly = ftrace_stub;
93 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
94 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
95 static struct ftrace_ops global_ops;
98 ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip);
101 * Traverse the ftrace_global_list, invoking all entries. The reason that we
102 * can use rcu_dereference_raw() is that elements removed from this list
103 * are simply leaked, so there is no need to interact with a grace-period
104 * mechanism. The rcu_dereference_raw() calls are needed to handle
105 * concurrent insertions into the ftrace_global_list.
107 * Silly Alpha and silly pointer-speculation compiler optimizations!
109 static void ftrace_global_list_func(unsigned long ip,
110 unsigned long parent_ip)
112 struct ftrace_ops *op;
114 if (unlikely(trace_recursion_test(TRACE_GLOBAL_BIT)))
117 trace_recursion_set(TRACE_GLOBAL_BIT);
118 op = rcu_dereference_raw(ftrace_global_list); /*see above*/
119 while (op != &ftrace_list_end) {
120 op->func(ip, parent_ip);
121 op = rcu_dereference_raw(op->next); /*see above*/
123 trace_recursion_clear(TRACE_GLOBAL_BIT);
126 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
128 if (!test_tsk_trace_trace(current))
131 ftrace_pid_function(ip, parent_ip);
134 static void set_ftrace_pid_function(ftrace_func_t func)
136 /* do not set ftrace_pid_function to itself! */
137 if (func != ftrace_pid_func)
138 ftrace_pid_function = func;
142 * clear_ftrace_function - reset the ftrace function
144 * This NULLs the ftrace function and in essence stops
145 * tracing. There may be lag
147 void clear_ftrace_function(void)
149 ftrace_trace_function = ftrace_stub;
150 __ftrace_trace_function = ftrace_stub;
151 __ftrace_trace_function_delay = ftrace_stub;
152 ftrace_pid_function = ftrace_stub;
155 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
157 * For those archs that do not test ftrace_trace_stop in their
158 * mcount call site, we need to do it from C.
160 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
162 if (function_trace_stop)
165 __ftrace_trace_function(ip, parent_ip);
169 static void update_global_ops(void)
174 * If there's only one function registered, then call that
175 * function directly. Otherwise, we need to iterate over the
176 * registered callers.
178 if (ftrace_global_list == &ftrace_list_end ||
179 ftrace_global_list->next == &ftrace_list_end)
180 func = ftrace_global_list->func;
182 func = ftrace_global_list_func;
184 /* If we filter on pids, update to use the pid function */
185 if (!list_empty(&ftrace_pids)) {
186 set_ftrace_pid_function(func);
187 func = ftrace_pid_func;
190 global_ops.func = func;
193 static void update_ftrace_function(void)
200 * If we are at the end of the list and this ops is
201 * not dynamic, then have the mcount trampoline call
202 * the function directly
204 if (ftrace_ops_list == &ftrace_list_end ||
205 (ftrace_ops_list->next == &ftrace_list_end &&
206 !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC)))
207 func = ftrace_ops_list->func;
209 func = ftrace_ops_list_func;
211 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
212 ftrace_trace_function = func;
214 #ifdef CONFIG_DYNAMIC_FTRACE
215 /* do not update till all functions have been modified */
216 __ftrace_trace_function_delay = func;
218 __ftrace_trace_function = func;
220 ftrace_trace_function = ftrace_test_stop_func;
224 static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
228 * We are entering ops into the list but another
229 * CPU might be walking that list. We need to make sure
230 * the ops->next pointer is valid before another CPU sees
231 * the ops pointer included into the list.
233 rcu_assign_pointer(*list, ops);
236 static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
238 struct ftrace_ops **p;
241 * If we are removing the last function, then simply point
242 * to the ftrace_stub.
244 if (*list == ops && ops->next == &ftrace_list_end) {
245 *list = &ftrace_list_end;
249 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
260 static int __register_ftrace_function(struct ftrace_ops *ops)
265 if (FTRACE_WARN_ON(ops == &global_ops))
268 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
271 if (!core_kernel_data((unsigned long)ops))
272 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
274 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
275 int first = ftrace_global_list == &ftrace_list_end;
276 add_ftrace_ops(&ftrace_global_list, ops);
277 ops->flags |= FTRACE_OPS_FL_ENABLED;
279 add_ftrace_ops(&ftrace_ops_list, &global_ops);
281 add_ftrace_ops(&ftrace_ops_list, ops);
284 update_ftrace_function();
289 static int __unregister_ftrace_function(struct ftrace_ops *ops)
296 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
299 if (FTRACE_WARN_ON(ops == &global_ops))
302 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
303 ret = remove_ftrace_ops(&ftrace_global_list, ops);
304 if (!ret && ftrace_global_list == &ftrace_list_end)
305 ret = remove_ftrace_ops(&ftrace_ops_list, &global_ops);
307 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
309 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
315 update_ftrace_function();
318 * Dynamic ops may be freed, we must make sure that all
319 * callers are done before leaving this function.
321 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
327 static void ftrace_update_pid_func(void)
329 /* Only do something if we are tracing something */
330 if (ftrace_trace_function == ftrace_stub)
333 update_ftrace_function();
336 #ifdef CONFIG_FUNCTION_PROFILER
337 struct ftrace_profile {
338 struct hlist_node node;
340 unsigned long counter;
341 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
342 unsigned long long time;
343 unsigned long long time_squared;
347 struct ftrace_profile_page {
348 struct ftrace_profile_page *next;
350 struct ftrace_profile records[];
353 struct ftrace_profile_stat {
355 struct hlist_head *hash;
356 struct ftrace_profile_page *pages;
357 struct ftrace_profile_page *start;
358 struct tracer_stat stat;
361 #define PROFILE_RECORDS_SIZE \
362 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
364 #define PROFILES_PER_PAGE \
365 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
367 static int ftrace_profile_bits __read_mostly;
368 static int ftrace_profile_enabled __read_mostly;
370 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
371 static DEFINE_MUTEX(ftrace_profile_lock);
373 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
375 #define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
378 function_stat_next(void *v, int idx)
380 struct ftrace_profile *rec = v;
381 struct ftrace_profile_page *pg;
383 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
389 if ((void *)rec >= (void *)&pg->records[pg->index]) {
393 rec = &pg->records[0];
401 static void *function_stat_start(struct tracer_stat *trace)
403 struct ftrace_profile_stat *stat =
404 container_of(trace, struct ftrace_profile_stat, stat);
406 if (!stat || !stat->start)
409 return function_stat_next(&stat->start->records[0], 0);
412 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
413 /* function graph compares on total time */
414 static int function_stat_cmp(void *p1, void *p2)
416 struct ftrace_profile *a = p1;
417 struct ftrace_profile *b = p2;
419 if (a->time < b->time)
421 if (a->time > b->time)
427 /* not function graph compares against hits */
428 static int function_stat_cmp(void *p1, void *p2)
430 struct ftrace_profile *a = p1;
431 struct ftrace_profile *b = p2;
433 if (a->counter < b->counter)
435 if (a->counter > b->counter)
442 static int function_stat_headers(struct seq_file *m)
444 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
445 seq_printf(m, " Function "
448 "--- ---- --- ---\n");
450 seq_printf(m, " Function Hit\n"
456 static int function_stat_show(struct seq_file *m, void *v)
458 struct ftrace_profile *rec = v;
459 char str[KSYM_SYMBOL_LEN];
461 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
462 static struct trace_seq s;
463 unsigned long long avg;
464 unsigned long long stddev;
466 mutex_lock(&ftrace_profile_lock);
468 /* we raced with function_profile_reset() */
469 if (unlikely(rec->counter == 0)) {
474 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
475 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
477 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
480 do_div(avg, rec->counter);
482 /* Sample standard deviation (s^2) */
483 if (rec->counter <= 1)
486 stddev = rec->time_squared - rec->counter * avg * avg;
488 * Divide only 1000 for ns^2 -> us^2 conversion.
489 * trace_print_graph_duration will divide 1000 again.
491 do_div(stddev, (rec->counter - 1) * 1000);
495 trace_print_graph_duration(rec->time, &s);
496 trace_seq_puts(&s, " ");
497 trace_print_graph_duration(avg, &s);
498 trace_seq_puts(&s, " ");
499 trace_print_graph_duration(stddev, &s);
500 trace_print_seq(m, &s);
504 mutex_unlock(&ftrace_profile_lock);
509 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
511 struct ftrace_profile_page *pg;
513 pg = stat->pages = stat->start;
516 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
521 memset(stat->hash, 0,
522 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
525 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
527 struct ftrace_profile_page *pg;
532 /* If we already allocated, do nothing */
536 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
540 #ifdef CONFIG_DYNAMIC_FTRACE
541 functions = ftrace_update_tot_cnt;
544 * We do not know the number of functions that exist because
545 * dynamic tracing is what counts them. With past experience
546 * we have around 20K functions. That should be more than enough.
547 * It is highly unlikely we will execute every function in
553 pg = stat->start = stat->pages;
555 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
557 for (i = 0; i < pages; i++) {
558 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
569 unsigned long tmp = (unsigned long)pg;
575 free_page((unsigned long)stat->pages);
582 static int ftrace_profile_init_cpu(int cpu)
584 struct ftrace_profile_stat *stat;
587 stat = &per_cpu(ftrace_profile_stats, cpu);
590 /* If the profile is already created, simply reset it */
591 ftrace_profile_reset(stat);
596 * We are profiling all functions, but usually only a few thousand
597 * functions are hit. We'll make a hash of 1024 items.
599 size = FTRACE_PROFILE_HASH_SIZE;
601 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
606 if (!ftrace_profile_bits) {
609 for (; size; size >>= 1)
610 ftrace_profile_bits++;
613 /* Preallocate the function profiling pages */
614 if (ftrace_profile_pages_init(stat) < 0) {
623 static int ftrace_profile_init(void)
628 for_each_online_cpu(cpu) {
629 ret = ftrace_profile_init_cpu(cpu);
637 /* interrupts must be disabled */
638 static struct ftrace_profile *
639 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
641 struct ftrace_profile *rec;
642 struct hlist_head *hhd;
643 struct hlist_node *n;
646 key = hash_long(ip, ftrace_profile_bits);
647 hhd = &stat->hash[key];
649 if (hlist_empty(hhd))
652 hlist_for_each_entry_rcu(rec, n, hhd, node) {
660 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
661 struct ftrace_profile *rec)
665 key = hash_long(rec->ip, ftrace_profile_bits);
666 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
670 * The memory is already allocated, this simply finds a new record to use.
672 static struct ftrace_profile *
673 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
675 struct ftrace_profile *rec = NULL;
677 /* prevent recursion (from NMIs) */
678 if (atomic_inc_return(&stat->disabled) != 1)
682 * Try to find the function again since an NMI
683 * could have added it
685 rec = ftrace_find_profiled_func(stat, ip);
689 if (stat->pages->index == PROFILES_PER_PAGE) {
690 if (!stat->pages->next)
692 stat->pages = stat->pages->next;
695 rec = &stat->pages->records[stat->pages->index++];
697 ftrace_add_profile(stat, rec);
700 atomic_dec(&stat->disabled);
706 function_profile_call(unsigned long ip, unsigned long parent_ip)
708 struct ftrace_profile_stat *stat;
709 struct ftrace_profile *rec;
712 if (!ftrace_profile_enabled)
715 local_irq_save(flags);
717 stat = &__get_cpu_var(ftrace_profile_stats);
718 if (!stat->hash || !ftrace_profile_enabled)
721 rec = ftrace_find_profiled_func(stat, ip);
723 rec = ftrace_profile_alloc(stat, ip);
730 local_irq_restore(flags);
733 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
734 static int profile_graph_entry(struct ftrace_graph_ent *trace)
736 function_profile_call(trace->func, 0);
740 static void profile_graph_return(struct ftrace_graph_ret *trace)
742 struct ftrace_profile_stat *stat;
743 unsigned long long calltime;
744 struct ftrace_profile *rec;
747 local_irq_save(flags);
748 stat = &__get_cpu_var(ftrace_profile_stats);
749 if (!stat->hash || !ftrace_profile_enabled)
752 /* If the calltime was zero'd ignore it */
753 if (!trace->calltime)
756 calltime = trace->rettime - trace->calltime;
758 if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
761 index = trace->depth;
763 /* Append this call time to the parent time to subtract */
765 current->ret_stack[index - 1].subtime += calltime;
767 if (current->ret_stack[index].subtime < calltime)
768 calltime -= current->ret_stack[index].subtime;
773 rec = ftrace_find_profiled_func(stat, trace->func);
775 rec->time += calltime;
776 rec->time_squared += calltime * calltime;
780 local_irq_restore(flags);
783 static int register_ftrace_profiler(void)
785 return register_ftrace_graph(&profile_graph_return,
786 &profile_graph_entry);
789 static void unregister_ftrace_profiler(void)
791 unregister_ftrace_graph();
794 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
795 .func = function_profile_call,
798 static int register_ftrace_profiler(void)
800 return register_ftrace_function(&ftrace_profile_ops);
803 static void unregister_ftrace_profiler(void)
805 unregister_ftrace_function(&ftrace_profile_ops);
807 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
810 ftrace_profile_write(struct file *filp, const char __user *ubuf,
811 size_t cnt, loff_t *ppos)
816 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
822 mutex_lock(&ftrace_profile_lock);
823 if (ftrace_profile_enabled ^ val) {
825 ret = ftrace_profile_init();
831 ret = register_ftrace_profiler();
836 ftrace_profile_enabled = 1;
838 ftrace_profile_enabled = 0;
840 * unregister_ftrace_profiler calls stop_machine
841 * so this acts like an synchronize_sched.
843 unregister_ftrace_profiler();
847 mutex_unlock(&ftrace_profile_lock);
855 ftrace_profile_read(struct file *filp, char __user *ubuf,
856 size_t cnt, loff_t *ppos)
858 char buf[64]; /* big enough to hold a number */
861 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
862 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
865 static const struct file_operations ftrace_profile_fops = {
866 .open = tracing_open_generic,
867 .read = ftrace_profile_read,
868 .write = ftrace_profile_write,
869 .llseek = default_llseek,
872 /* used to initialize the real stat files */
873 static struct tracer_stat function_stats __initdata = {
875 .stat_start = function_stat_start,
876 .stat_next = function_stat_next,
877 .stat_cmp = function_stat_cmp,
878 .stat_headers = function_stat_headers,
879 .stat_show = function_stat_show
882 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
884 struct ftrace_profile_stat *stat;
885 struct dentry *entry;
890 for_each_possible_cpu(cpu) {
891 stat = &per_cpu(ftrace_profile_stats, cpu);
893 /* allocate enough for function name + cpu number */
894 name = kmalloc(32, GFP_KERNEL);
897 * The files created are permanent, if something happens
898 * we still do not free memory.
901 "Could not allocate stat file for cpu %d\n",
905 stat->stat = function_stats;
906 snprintf(name, 32, "function%d", cpu);
907 stat->stat.name = name;
908 ret = register_stat_tracer(&stat->stat);
911 "Could not register function stat for cpu %d\n",
918 entry = debugfs_create_file("function_profile_enabled", 0644,
919 d_tracer, NULL, &ftrace_profile_fops);
921 pr_warning("Could not create debugfs "
922 "'function_profile_enabled' entry\n");
925 #else /* CONFIG_FUNCTION_PROFILER */
926 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
929 #endif /* CONFIG_FUNCTION_PROFILER */
931 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
933 #ifdef CONFIG_DYNAMIC_FTRACE
935 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
936 # error Dynamic ftrace depends on MCOUNT_RECORD
939 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
941 struct ftrace_func_probe {
942 struct hlist_node node;
943 struct ftrace_probe_ops *ops;
950 struct ftrace_func_entry {
951 struct hlist_node hlist;
956 unsigned long size_bits;
957 struct hlist_head *buckets;
963 * We make these constant because no one should touch them,
964 * but they are used as the default "empty hash", to avoid allocating
965 * it all the time. These are in a read only section such that if
966 * anyone does try to modify it, it will cause an exception.
968 static const struct hlist_head empty_buckets[1];
969 static const struct ftrace_hash empty_hash = {
970 .buckets = (struct hlist_head *)empty_buckets,
972 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
974 static struct ftrace_ops global_ops = {
976 .notrace_hash = EMPTY_HASH,
977 .filter_hash = EMPTY_HASH,
980 static struct dyn_ftrace *ftrace_new_addrs;
982 static DEFINE_MUTEX(ftrace_regex_lock);
985 struct ftrace_page *next;
986 struct dyn_ftrace *records;
991 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
992 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
994 /* estimate from running different kernels */
995 #define NR_TO_INIT 10000
997 static struct ftrace_page *ftrace_pages_start;
998 static struct ftrace_page *ftrace_pages;
1000 static struct ftrace_func_entry *
1001 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1004 struct ftrace_func_entry *entry;
1005 struct hlist_head *hhd;
1006 struct hlist_node *n;
1011 if (hash->size_bits > 0)
1012 key = hash_long(ip, hash->size_bits);
1016 hhd = &hash->buckets[key];
1018 hlist_for_each_entry_rcu(entry, n, hhd, hlist) {
1019 if (entry->ip == ip)
1025 static void __add_hash_entry(struct ftrace_hash *hash,
1026 struct ftrace_func_entry *entry)
1028 struct hlist_head *hhd;
1031 if (hash->size_bits)
1032 key = hash_long(entry->ip, hash->size_bits);
1036 hhd = &hash->buckets[key];
1037 hlist_add_head(&entry->hlist, hhd);
1041 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1043 struct ftrace_func_entry *entry;
1045 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1050 __add_hash_entry(hash, entry);
1056 free_hash_entry(struct ftrace_hash *hash,
1057 struct ftrace_func_entry *entry)
1059 hlist_del(&entry->hlist);
1065 remove_hash_entry(struct ftrace_hash *hash,
1066 struct ftrace_func_entry *entry)
1068 hlist_del(&entry->hlist);
1072 static void ftrace_hash_clear(struct ftrace_hash *hash)
1074 struct hlist_head *hhd;
1075 struct hlist_node *tp, *tn;
1076 struct ftrace_func_entry *entry;
1077 int size = 1 << hash->size_bits;
1083 for (i = 0; i < size; i++) {
1084 hhd = &hash->buckets[i];
1085 hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist)
1086 free_hash_entry(hash, entry);
1088 FTRACE_WARN_ON(hash->count);
1091 static void free_ftrace_hash(struct ftrace_hash *hash)
1093 if (!hash || hash == EMPTY_HASH)
1095 ftrace_hash_clear(hash);
1096 kfree(hash->buckets);
1100 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1102 struct ftrace_hash *hash;
1104 hash = container_of(rcu, struct ftrace_hash, rcu);
1105 free_ftrace_hash(hash);
1108 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1110 if (!hash || hash == EMPTY_HASH)
1112 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1115 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1117 struct ftrace_hash *hash;
1120 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1124 size = 1 << size_bits;
1125 hash->buckets = kzalloc(sizeof(*hash->buckets) * size, GFP_KERNEL);
1127 if (!hash->buckets) {
1132 hash->size_bits = size_bits;
1137 static struct ftrace_hash *
1138 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1140 struct ftrace_func_entry *entry;
1141 struct ftrace_hash *new_hash;
1142 struct hlist_node *tp;
1147 new_hash = alloc_ftrace_hash(size_bits);
1152 if (!hash || !hash->count)
1155 size = 1 << hash->size_bits;
1156 for (i = 0; i < size; i++) {
1157 hlist_for_each_entry(entry, tp, &hash->buckets[i], hlist) {
1158 ret = add_hash_entry(new_hash, entry->ip);
1164 FTRACE_WARN_ON(new_hash->count != hash->count);
1169 free_ftrace_hash(new_hash);
1174 ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash);
1176 ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash);
1179 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1180 struct ftrace_hash **dst, struct ftrace_hash *src)
1182 struct ftrace_func_entry *entry;
1183 struct hlist_node *tp, *tn;
1184 struct hlist_head *hhd;
1185 struct ftrace_hash *old_hash;
1186 struct ftrace_hash *new_hash;
1188 int size = src->count;
1194 * Remove the current set, update the hash and add
1197 ftrace_hash_rec_disable(ops, enable);
1200 * If the new source is empty, just free dst and assign it
1204 free_ftrace_hash_rcu(*dst);
1205 rcu_assign_pointer(*dst, EMPTY_HASH);
1206 /* still need to update the function records */
1212 * Make the hash size about 1/2 the # found
1214 for (size /= 2; size; size >>= 1)
1217 /* Don't allocate too much */
1218 if (bits > FTRACE_HASH_MAX_BITS)
1219 bits = FTRACE_HASH_MAX_BITS;
1222 new_hash = alloc_ftrace_hash(bits);
1226 size = 1 << src->size_bits;
1227 for (i = 0; i < size; i++) {
1228 hhd = &src->buckets[i];
1229 hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist) {
1231 key = hash_long(entry->ip, bits);
1234 remove_hash_entry(src, entry);
1235 __add_hash_entry(new_hash, entry);
1240 rcu_assign_pointer(*dst, new_hash);
1241 free_ftrace_hash_rcu(old_hash);
1246 * Enable regardless of ret:
1247 * On success, we enable the new hash.
1248 * On failure, we re-enable the original hash.
1250 ftrace_hash_rec_enable(ops, enable);
1256 * Test the hashes for this ops to see if we want to call
1257 * the ops->func or not.
1259 * It's a match if the ip is in the ops->filter_hash or
1260 * the filter_hash does not exist or is empty,
1262 * the ip is not in the ops->notrace_hash.
1264 * This needs to be called with preemption disabled as
1265 * the hashes are freed with call_rcu_sched().
1268 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
1270 struct ftrace_hash *filter_hash;
1271 struct ftrace_hash *notrace_hash;
1274 filter_hash = rcu_dereference_raw(ops->filter_hash);
1275 notrace_hash = rcu_dereference_raw(ops->notrace_hash);
1277 if ((!filter_hash || !filter_hash->count ||
1278 ftrace_lookup_ip(filter_hash, ip)) &&
1279 (!notrace_hash || !notrace_hash->count ||
1280 !ftrace_lookup_ip(notrace_hash, ip)))
1289 * This is a double for. Do not use 'break' to break out of the loop,
1290 * you must use a goto.
1292 #define do_for_each_ftrace_rec(pg, rec) \
1293 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1295 for (_____i = 0; _____i < pg->index; _____i++) { \
1296 rec = &pg->records[_____i];
1298 #define while_for_each_ftrace_rec() \
1303 * ftrace_location - return true if the ip giving is a traced location
1304 * @ip: the instruction pointer to check
1306 * Returns 1 if @ip given is a pointer to a ftrace location.
1307 * That is, the instruction that is either a NOP or call to
1308 * the function tracer. It checks the ftrace internal tables to
1309 * determine if the address belongs or not.
1311 int ftrace_location(unsigned long ip)
1313 struct ftrace_page *pg;
1314 struct dyn_ftrace *rec;
1316 do_for_each_ftrace_rec(pg, rec) {
1319 } while_for_each_ftrace_rec();
1324 static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
1328 struct ftrace_hash *hash;
1329 struct ftrace_hash *other_hash;
1330 struct ftrace_page *pg;
1331 struct dyn_ftrace *rec;
1335 /* Only update if the ops has been registered */
1336 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1340 * In the filter_hash case:
1341 * If the count is zero, we update all records.
1342 * Otherwise we just update the items in the hash.
1344 * In the notrace_hash case:
1345 * We enable the update in the hash.
1346 * As disabling notrace means enabling the tracing,
1347 * and enabling notrace means disabling, the inc variable
1351 hash = ops->filter_hash;
1352 other_hash = ops->notrace_hash;
1353 if (!hash || !hash->count)
1357 hash = ops->notrace_hash;
1358 other_hash = ops->filter_hash;
1360 * If the notrace hash has no items,
1361 * then there's nothing to do.
1363 if (hash && !hash->count)
1367 do_for_each_ftrace_rec(pg, rec) {
1368 int in_other_hash = 0;
1374 * Only the filter_hash affects all records.
1375 * Update if the record is not in the notrace hash.
1377 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1380 in_hash = hash && !!ftrace_lookup_ip(hash, rec->ip);
1381 in_other_hash = other_hash && !!ftrace_lookup_ip(other_hash, rec->ip);
1386 if (filter_hash && in_hash && !in_other_hash)
1388 else if (!filter_hash && in_hash &&
1389 (in_other_hash || !other_hash->count))
1397 if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX))
1400 if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
1405 /* Shortcut, if we handled all records, we are done. */
1406 if (!all && count == hash->count)
1408 } while_for_each_ftrace_rec();
1411 static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
1414 __ftrace_hash_rec_update(ops, filter_hash, 0);
1417 static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
1420 __ftrace_hash_rec_update(ops, filter_hash, 1);
1423 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
1425 if (ftrace_pages->index == ftrace_pages->size) {
1426 /* We should have allocated enough */
1427 if (WARN_ON(!ftrace_pages->next))
1429 ftrace_pages = ftrace_pages->next;
1432 return &ftrace_pages->records[ftrace_pages->index++];
1435 static struct dyn_ftrace *
1436 ftrace_record_ip(unsigned long ip)
1438 struct dyn_ftrace *rec;
1440 if (ftrace_disabled)
1443 rec = ftrace_alloc_dyn_node(ip);
1448 rec->newlist = ftrace_new_addrs;
1449 ftrace_new_addrs = rec;
1454 static void print_ip_ins(const char *fmt, unsigned char *p)
1458 printk(KERN_CONT "%s", fmt);
1460 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1461 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1465 * ftrace_bug - report and shutdown function tracer
1466 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1467 * @ip: The address that failed
1469 * The arch code that enables or disables the function tracing
1470 * can call ftrace_bug() when it has detected a problem in
1471 * modifying the code. @failed should be one of either:
1472 * EFAULT - if the problem happens on reading the @ip address
1473 * EINVAL - if what is read at @ip is not what was expected
1474 * EPERM - if the problem happens on writting to the @ip address
1476 void ftrace_bug(int failed, unsigned long ip)
1480 FTRACE_WARN_ON_ONCE(1);
1481 pr_info("ftrace faulted on modifying ");
1485 FTRACE_WARN_ON_ONCE(1);
1486 pr_info("ftrace failed to modify ");
1488 print_ip_ins(" actual: ", (unsigned char *)ip);
1489 printk(KERN_CONT "\n");
1492 FTRACE_WARN_ON_ONCE(1);
1493 pr_info("ftrace faulted on writing ");
1497 FTRACE_WARN_ON_ONCE(1);
1498 pr_info("ftrace faulted on unknown error ");
1504 /* Return 1 if the address range is reserved for ftrace */
1505 int ftrace_text_reserved(void *start, void *end)
1507 struct dyn_ftrace *rec;
1508 struct ftrace_page *pg;
1510 do_for_each_ftrace_rec(pg, rec) {
1511 if (rec->ip <= (unsigned long)end &&
1512 rec->ip + MCOUNT_INSN_SIZE > (unsigned long)start)
1514 } while_for_each_ftrace_rec();
1518 static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
1520 unsigned long flag = 0UL;
1523 * If we are updating calls:
1525 * If the record has a ref count, then we need to enable it
1526 * because someone is using it.
1528 * Otherwise we make sure its disabled.
1530 * If we are disabling calls, then disable all records that
1533 if (enable && (rec->flags & ~FTRACE_FL_MASK))
1534 flag = FTRACE_FL_ENABLED;
1536 /* If the state of this record hasn't changed, then do nothing */
1537 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1538 return FTRACE_UPDATE_IGNORE;
1542 rec->flags |= FTRACE_FL_ENABLED;
1543 return FTRACE_UPDATE_MAKE_CALL;
1547 rec->flags &= ~FTRACE_FL_ENABLED;
1549 return FTRACE_UPDATE_MAKE_NOP;
1553 * ftrace_update_record, set a record that now is tracing or not
1554 * @rec: the record to update
1555 * @enable: set to 1 if the record is tracing, zero to force disable
1557 * The records that represent all functions that can be traced need
1558 * to be updated when tracing has been enabled.
1560 int ftrace_update_record(struct dyn_ftrace *rec, int enable)
1562 return ftrace_check_record(rec, enable, 1);
1566 * ftrace_test_record, check if the record has been enabled or not
1567 * @rec: the record to test
1568 * @enable: set to 1 to check if enabled, 0 if it is disabled
1570 * The arch code may need to test if a record is already set to
1571 * tracing to determine how to modify the function code that it
1574 int ftrace_test_record(struct dyn_ftrace *rec, int enable)
1576 return ftrace_check_record(rec, enable, 0);
1580 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1582 unsigned long ftrace_addr;
1585 ftrace_addr = (unsigned long)FTRACE_ADDR;
1587 ret = ftrace_update_record(rec, enable);
1590 case FTRACE_UPDATE_IGNORE:
1593 case FTRACE_UPDATE_MAKE_CALL:
1594 return ftrace_make_call(rec, ftrace_addr);
1596 case FTRACE_UPDATE_MAKE_NOP:
1597 return ftrace_make_nop(NULL, rec, ftrace_addr);
1600 return -1; /* unknow ftrace bug */
1603 static void ftrace_replace_code(int update)
1605 struct dyn_ftrace *rec;
1606 struct ftrace_page *pg;
1609 if (unlikely(ftrace_disabled))
1612 do_for_each_ftrace_rec(pg, rec) {
1613 failed = __ftrace_replace_code(rec, update);
1615 ftrace_bug(failed, rec->ip);
1616 /* Stop processing */
1619 } while_for_each_ftrace_rec();
1622 struct ftrace_rec_iter {
1623 struct ftrace_page *pg;
1628 * ftrace_rec_iter_start, start up iterating over traced functions
1630 * Returns an iterator handle that is used to iterate over all
1631 * the records that represent address locations where functions
1634 * May return NULL if no records are available.
1636 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
1639 * We only use a single iterator.
1640 * Protected by the ftrace_lock mutex.
1642 static struct ftrace_rec_iter ftrace_rec_iter;
1643 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
1645 iter->pg = ftrace_pages_start;
1648 /* Could have empty pages */
1649 while (iter->pg && !iter->pg->index)
1650 iter->pg = iter->pg->next;
1659 * ftrace_rec_iter_next, get the next record to process.
1660 * @iter: The handle to the iterator.
1662 * Returns the next iterator after the given iterator @iter.
1664 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
1668 if (iter->index >= iter->pg->index) {
1669 iter->pg = iter->pg->next;
1672 /* Could have empty pages */
1673 while (iter->pg && !iter->pg->index)
1674 iter->pg = iter->pg->next;
1684 * ftrace_rec_iter_record, get the record at the iterator location
1685 * @iter: The current iterator location
1687 * Returns the record that the current @iter is at.
1689 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
1691 return &iter->pg->records[iter->index];
1695 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1702 if (unlikely(ftrace_disabled))
1705 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1707 ftrace_bug(ret, ip);
1714 * archs can override this function if they must do something
1715 * before the modifying code is performed.
1717 int __weak ftrace_arch_code_modify_prepare(void)
1723 * archs can override this function if they must do something
1724 * after the modifying code is performed.
1726 int __weak ftrace_arch_code_modify_post_process(void)
1731 static int __ftrace_modify_code(void *data)
1733 int *command = data;
1735 if (*command & FTRACE_UPDATE_CALLS)
1736 ftrace_replace_code(1);
1737 else if (*command & FTRACE_DISABLE_CALLS)
1738 ftrace_replace_code(0);
1740 if (*command & FTRACE_UPDATE_TRACE_FUNC)
1741 ftrace_update_ftrace_func(ftrace_trace_function);
1743 if (*command & FTRACE_START_FUNC_RET)
1744 ftrace_enable_ftrace_graph_caller();
1745 else if (*command & FTRACE_STOP_FUNC_RET)
1746 ftrace_disable_ftrace_graph_caller();
1752 * ftrace_run_stop_machine, go back to the stop machine method
1753 * @command: The command to tell ftrace what to do
1755 * If an arch needs to fall back to the stop machine method, the
1756 * it can call this function.
1758 void ftrace_run_stop_machine(int command)
1760 stop_machine(__ftrace_modify_code, &command, NULL);
1764 * arch_ftrace_update_code, modify the code to trace or not trace
1765 * @command: The command that needs to be done
1767 * Archs can override this function if it does not need to
1768 * run stop_machine() to modify code.
1770 void __weak arch_ftrace_update_code(int command)
1772 ftrace_run_stop_machine(command);
1775 static void ftrace_run_update_code(int command)
1779 ret = ftrace_arch_code_modify_prepare();
1780 FTRACE_WARN_ON(ret);
1784 * Do not call function tracer while we update the code.
1785 * We are in stop machine.
1787 function_trace_stop++;
1790 * By default we use stop_machine() to modify the code.
1791 * But archs can do what ever they want as long as it
1792 * is safe. The stop_machine() is the safest, but also
1793 * produces the most overhead.
1795 arch_ftrace_update_code(command);
1797 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
1799 * For archs that call ftrace_test_stop_func(), we must
1800 * wait till after we update all the function callers
1801 * before we update the callback. This keeps different
1802 * ops that record different functions from corrupting
1805 __ftrace_trace_function = __ftrace_trace_function_delay;
1807 function_trace_stop--;
1809 ret = ftrace_arch_code_modify_post_process();
1810 FTRACE_WARN_ON(ret);
1813 static ftrace_func_t saved_ftrace_func;
1814 static int ftrace_start_up;
1815 static int global_start_up;
1817 static void ftrace_startup_enable(int command)
1819 if (saved_ftrace_func != ftrace_trace_function) {
1820 saved_ftrace_func = ftrace_trace_function;
1821 command |= FTRACE_UPDATE_TRACE_FUNC;
1824 if (!command || !ftrace_enabled)
1827 ftrace_run_update_code(command);
1830 static int ftrace_startup(struct ftrace_ops *ops, int command)
1832 bool hash_enable = true;
1834 if (unlikely(ftrace_disabled))
1838 command |= FTRACE_UPDATE_CALLS;
1840 /* ops marked global share the filter hashes */
1841 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
1843 /* Don't update hash if global is already set */
1844 if (global_start_up)
1845 hash_enable = false;
1849 ops->flags |= FTRACE_OPS_FL_ENABLED;
1851 ftrace_hash_rec_enable(ops, 1);
1853 ftrace_startup_enable(command);
1858 static void ftrace_shutdown(struct ftrace_ops *ops, int command)
1860 bool hash_disable = true;
1862 if (unlikely(ftrace_disabled))
1867 * Just warn in case of unbalance, no need to kill ftrace, it's not
1868 * critical but the ftrace_call callers may be never nopped again after
1869 * further ftrace uses.
1871 WARN_ON_ONCE(ftrace_start_up < 0);
1873 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
1876 WARN_ON_ONCE(global_start_up < 0);
1877 /* Don't update hash if global still has users */
1878 if (global_start_up) {
1879 WARN_ON_ONCE(!ftrace_start_up);
1880 hash_disable = false;
1885 ftrace_hash_rec_disable(ops, 1);
1887 if (ops != &global_ops || !global_start_up)
1888 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
1890 command |= FTRACE_UPDATE_CALLS;
1892 if (saved_ftrace_func != ftrace_trace_function) {
1893 saved_ftrace_func = ftrace_trace_function;
1894 command |= FTRACE_UPDATE_TRACE_FUNC;
1897 if (!command || !ftrace_enabled)
1900 ftrace_run_update_code(command);
1903 static void ftrace_startup_sysctl(void)
1905 if (unlikely(ftrace_disabled))
1908 /* Force update next time */
1909 saved_ftrace_func = NULL;
1910 /* ftrace_start_up is true if we want ftrace running */
1911 if (ftrace_start_up)
1912 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
1915 static void ftrace_shutdown_sysctl(void)
1917 if (unlikely(ftrace_disabled))
1920 /* ftrace_start_up is true if ftrace is running */
1921 if (ftrace_start_up)
1922 ftrace_run_update_code(FTRACE_DISABLE_CALLS);
1925 static cycle_t ftrace_update_time;
1926 static unsigned long ftrace_update_cnt;
1927 unsigned long ftrace_update_tot_cnt;
1929 static int ops_traces_mod(struct ftrace_ops *ops)
1931 struct ftrace_hash *hash;
1933 hash = ops->filter_hash;
1934 return !!(!hash || !hash->count);
1937 static int ftrace_update_code(struct module *mod)
1939 struct dyn_ftrace *p;
1940 cycle_t start, stop;
1941 unsigned long ref = 0;
1944 * When adding a module, we need to check if tracers are
1945 * currently enabled and if they are set to trace all functions.
1946 * If they are, we need to enable the module functions as well
1947 * as update the reference counts for those function records.
1950 struct ftrace_ops *ops;
1952 for (ops = ftrace_ops_list;
1953 ops != &ftrace_list_end; ops = ops->next) {
1954 if (ops->flags & FTRACE_OPS_FL_ENABLED &&
1955 ops_traces_mod(ops))
1960 start = ftrace_now(raw_smp_processor_id());
1961 ftrace_update_cnt = 0;
1963 while (ftrace_new_addrs) {
1965 /* If something went wrong, bail without enabling anything */
1966 if (unlikely(ftrace_disabled))
1969 p = ftrace_new_addrs;
1970 ftrace_new_addrs = p->newlist;
1974 * Do the initial record conversion from mcount jump
1975 * to the NOP instructions.
1977 if (!ftrace_code_disable(mod, p))
1980 ftrace_update_cnt++;
1983 * If the tracing is enabled, go ahead and enable the record.
1985 * The reason not to enable the record immediatelly is the
1986 * inherent check of ftrace_make_nop/ftrace_make_call for
1987 * correct previous instructions. Making first the NOP
1988 * conversion puts the module to the correct state, thus
1989 * passing the ftrace_make_call check.
1991 if (ftrace_start_up && ref) {
1992 int failed = __ftrace_replace_code(p, 1);
1994 ftrace_bug(failed, p->ip);
1998 stop = ftrace_now(raw_smp_processor_id());
1999 ftrace_update_time = stop - start;
2000 ftrace_update_tot_cnt += ftrace_update_cnt;
2005 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2010 if (WARN_ON(!count))
2013 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2016 * We want to fill as much as possible. No more than a page
2019 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2023 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2026 /* if we can't allocate this size, try something smaller */
2033 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2042 static struct ftrace_page *
2043 ftrace_allocate_pages(unsigned long num_to_init)
2045 struct ftrace_page *start_pg;
2046 struct ftrace_page *pg;
2053 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
2058 * Try to allocate as much as possible in one continues
2059 * location that fills in all of the space. We want to
2060 * waste as little space as possible.
2063 cnt = ftrace_allocate_records(pg, num_to_init);
2071 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
2082 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
2083 free_pages((unsigned long)pg->records, order);
2084 start_pg = pg->next;
2088 pr_info("ftrace: FAILED to allocate memory for functions\n");
2092 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
2097 pr_info("ftrace: No functions to be traced?\n");
2101 cnt = num_to_init / ENTRIES_PER_PAGE;
2102 pr_info("ftrace: allocating %ld entries in %d pages\n",
2103 num_to_init, cnt + 1);
2109 FTRACE_ITER_FILTER = (1 << 0),
2110 FTRACE_ITER_NOTRACE = (1 << 1),
2111 FTRACE_ITER_PRINTALL = (1 << 2),
2112 FTRACE_ITER_HASH = (1 << 3),
2113 FTRACE_ITER_ENABLED = (1 << 4),
2116 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
2118 struct ftrace_iterator {
2121 struct ftrace_page *pg;
2122 struct dyn_ftrace *func;
2123 struct ftrace_func_probe *probe;
2124 struct trace_parser parser;
2125 struct ftrace_hash *hash;
2126 struct ftrace_ops *ops;
2133 t_hash_next(struct seq_file *m, loff_t *pos)
2135 struct ftrace_iterator *iter = m->private;
2136 struct hlist_node *hnd = NULL;
2137 struct hlist_head *hhd;
2143 hnd = &iter->probe->node;
2145 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
2148 hhd = &ftrace_func_hash[iter->hidx];
2150 if (hlist_empty(hhd)) {
2166 if (WARN_ON_ONCE(!hnd))
2169 iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
2174 static void *t_hash_start(struct seq_file *m, loff_t *pos)
2176 struct ftrace_iterator *iter = m->private;
2180 if (iter->func_pos > *pos)
2184 for (l = 0; l <= (*pos - iter->func_pos); ) {
2185 p = t_hash_next(m, &l);
2192 /* Only set this if we have an item */
2193 iter->flags |= FTRACE_ITER_HASH;
2199 t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
2201 struct ftrace_func_probe *rec;
2204 if (WARN_ON_ONCE(!rec))
2207 if (rec->ops->print)
2208 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
2210 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
2213 seq_printf(m, ":%p", rec->data);
2220 t_next(struct seq_file *m, void *v, loff_t *pos)
2222 struct ftrace_iterator *iter = m->private;
2223 struct ftrace_ops *ops = &global_ops;
2224 struct dyn_ftrace *rec = NULL;
2226 if (unlikely(ftrace_disabled))
2229 if (iter->flags & FTRACE_ITER_HASH)
2230 return t_hash_next(m, pos);
2233 iter->pos = iter->func_pos = *pos;
2235 if (iter->flags & FTRACE_ITER_PRINTALL)
2236 return t_hash_start(m, pos);
2239 if (iter->idx >= iter->pg->index) {
2240 if (iter->pg->next) {
2241 iter->pg = iter->pg->next;
2246 rec = &iter->pg->records[iter->idx++];
2247 if (((iter->flags & FTRACE_ITER_FILTER) &&
2248 !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||
2250 ((iter->flags & FTRACE_ITER_NOTRACE) &&
2251 !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
2253 ((iter->flags & FTRACE_ITER_ENABLED) &&
2254 !(rec->flags & ~FTRACE_FL_MASK))) {
2262 return t_hash_start(m, pos);
2269 static void reset_iter_read(struct ftrace_iterator *iter)
2273 iter->flags &= ~(FTRACE_ITER_PRINTALL & FTRACE_ITER_HASH);
2276 static void *t_start(struct seq_file *m, loff_t *pos)
2278 struct ftrace_iterator *iter = m->private;
2279 struct ftrace_ops *ops = &global_ops;
2283 mutex_lock(&ftrace_lock);
2285 if (unlikely(ftrace_disabled))
2289 * If an lseek was done, then reset and start from beginning.
2291 if (*pos < iter->pos)
2292 reset_iter_read(iter);
2295 * For set_ftrace_filter reading, if we have the filter
2296 * off, we can short cut and just print out that all
2297 * functions are enabled.
2299 if (iter->flags & FTRACE_ITER_FILTER && !ops->filter_hash->count) {
2301 return t_hash_start(m, pos);
2302 iter->flags |= FTRACE_ITER_PRINTALL;
2303 /* reset in case of seek/pread */
2304 iter->flags &= ~FTRACE_ITER_HASH;
2308 if (iter->flags & FTRACE_ITER_HASH)
2309 return t_hash_start(m, pos);
2312 * Unfortunately, we need to restart at ftrace_pages_start
2313 * every time we let go of the ftrace_mutex. This is because
2314 * those pointers can change without the lock.
2316 iter->pg = ftrace_pages_start;
2318 for (l = 0; l <= *pos; ) {
2319 p = t_next(m, p, &l);
2325 if (iter->flags & FTRACE_ITER_FILTER)
2326 return t_hash_start(m, pos);
2334 static void t_stop(struct seq_file *m, void *p)
2336 mutex_unlock(&ftrace_lock);
2339 static int t_show(struct seq_file *m, void *v)
2341 struct ftrace_iterator *iter = m->private;
2342 struct dyn_ftrace *rec;
2344 if (iter->flags & FTRACE_ITER_HASH)
2345 return t_hash_show(m, iter);
2347 if (iter->flags & FTRACE_ITER_PRINTALL) {
2348 seq_printf(m, "#### all functions enabled ####\n");
2357 seq_printf(m, "%ps", (void *)rec->ip);
2358 if (iter->flags & FTRACE_ITER_ENABLED)
2359 seq_printf(m, " (%ld)",
2360 rec->flags & ~FTRACE_FL_MASK);
2361 seq_printf(m, "\n");
2366 static const struct seq_operations show_ftrace_seq_ops = {
2374 ftrace_avail_open(struct inode *inode, struct file *file)
2376 struct ftrace_iterator *iter;
2379 if (unlikely(ftrace_disabled))
2382 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2386 iter->pg = ftrace_pages_start;
2388 ret = seq_open(file, &show_ftrace_seq_ops);
2390 struct seq_file *m = file->private_data;
2401 ftrace_enabled_open(struct inode *inode, struct file *file)
2403 struct ftrace_iterator *iter;
2406 if (unlikely(ftrace_disabled))
2409 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2413 iter->pg = ftrace_pages_start;
2414 iter->flags = FTRACE_ITER_ENABLED;
2416 ret = seq_open(file, &show_ftrace_seq_ops);
2418 struct seq_file *m = file->private_data;
2428 static void ftrace_filter_reset(struct ftrace_hash *hash)
2430 mutex_lock(&ftrace_lock);
2431 ftrace_hash_clear(hash);
2432 mutex_unlock(&ftrace_lock);
2436 ftrace_regex_open(struct ftrace_ops *ops, int flag,
2437 struct inode *inode, struct file *file)
2439 struct ftrace_iterator *iter;
2440 struct ftrace_hash *hash;
2443 if (unlikely(ftrace_disabled))
2446 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2450 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
2455 if (flag & FTRACE_ITER_NOTRACE)
2456 hash = ops->notrace_hash;
2458 hash = ops->filter_hash;
2463 if (file->f_mode & FMODE_WRITE) {
2464 mutex_lock(&ftrace_lock);
2465 iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
2466 mutex_unlock(&ftrace_lock);
2469 trace_parser_put(&iter->parser);
2475 mutex_lock(&ftrace_regex_lock);
2477 if ((file->f_mode & FMODE_WRITE) &&
2478 (file->f_flags & O_TRUNC))
2479 ftrace_filter_reset(iter->hash);
2481 if (file->f_mode & FMODE_READ) {
2482 iter->pg = ftrace_pages_start;
2484 ret = seq_open(file, &show_ftrace_seq_ops);
2486 struct seq_file *m = file->private_data;
2490 free_ftrace_hash(iter->hash);
2491 trace_parser_put(&iter->parser);
2495 file->private_data = iter;
2496 mutex_unlock(&ftrace_regex_lock);
2502 ftrace_filter_open(struct inode *inode, struct file *file)
2504 return ftrace_regex_open(&global_ops, FTRACE_ITER_FILTER,
2509 ftrace_notrace_open(struct inode *inode, struct file *file)
2511 return ftrace_regex_open(&global_ops, FTRACE_ITER_NOTRACE,
2516 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
2520 if (file->f_mode & FMODE_READ)
2521 ret = seq_lseek(file, offset, origin);
2523 file->f_pos = ret = 1;
2528 static int ftrace_match(char *str, char *regex, int len, int type)
2535 if (strcmp(str, regex) == 0)
2538 case MATCH_FRONT_ONLY:
2539 if (strncmp(str, regex, len) == 0)
2542 case MATCH_MIDDLE_ONLY:
2543 if (strstr(str, regex))
2546 case MATCH_END_ONLY:
2548 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
2557 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
2559 struct ftrace_func_entry *entry;
2562 entry = ftrace_lookup_ip(hash, rec->ip);
2564 /* Do nothing if it doesn't exist */
2568 free_hash_entry(hash, entry);
2570 /* Do nothing if it exists */
2574 ret = add_hash_entry(hash, rec->ip);
2580 ftrace_match_record(struct dyn_ftrace *rec, char *mod,
2581 char *regex, int len, int type)
2583 char str[KSYM_SYMBOL_LEN];
2586 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
2589 /* module lookup requires matching the module */
2590 if (!modname || strcmp(modname, mod))
2593 /* blank search means to match all funcs in the mod */
2598 return ftrace_match(str, regex, len, type);
2602 match_records(struct ftrace_hash *hash, char *buff,
2603 int len, char *mod, int not)
2605 unsigned search_len = 0;
2606 struct ftrace_page *pg;
2607 struct dyn_ftrace *rec;
2608 int type = MATCH_FULL;
2609 char *search = buff;
2614 type = filter_parse_regex(buff, len, &search, ¬);
2615 search_len = strlen(search);
2618 mutex_lock(&ftrace_lock);
2620 if (unlikely(ftrace_disabled))
2623 do_for_each_ftrace_rec(pg, rec) {
2624 if (ftrace_match_record(rec, mod, search, search_len, type)) {
2625 ret = enter_record(hash, rec, not);
2632 } while_for_each_ftrace_rec();
2634 mutex_unlock(&ftrace_lock);
2640 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
2642 return match_records(hash, buff, len, NULL, 0);
2646 ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
2650 /* blank or '*' mean the same */
2651 if (strcmp(buff, "*") == 0)
2654 /* handle the case of 'dont filter this module' */
2655 if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
2660 return match_records(hash, buff, strlen(buff), mod, not);
2664 * We register the module command as a template to show others how
2665 * to register the a command as well.
2669 ftrace_mod_callback(struct ftrace_hash *hash,
2670 char *func, char *cmd, char *param, int enable)
2676 * cmd == 'mod' because we only registered this func
2677 * for the 'mod' ftrace_func_command.
2678 * But if you register one func with multiple commands,
2679 * you can tell which command was used by the cmd
2683 /* we must have a module name */
2687 mod = strsep(¶m, ":");
2691 ret = ftrace_match_module_records(hash, func, mod);
2700 static struct ftrace_func_command ftrace_mod_cmd = {
2702 .func = ftrace_mod_callback,
2705 static int __init ftrace_mod_cmd_init(void)
2707 return register_ftrace_command(&ftrace_mod_cmd);
2709 device_initcall(ftrace_mod_cmd_init);
2712 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
2714 struct ftrace_func_probe *entry;
2715 struct hlist_head *hhd;
2716 struct hlist_node *n;
2719 key = hash_long(ip, FTRACE_HASH_BITS);
2721 hhd = &ftrace_func_hash[key];
2723 if (hlist_empty(hhd))
2727 * Disable preemption for these calls to prevent a RCU grace
2728 * period. This syncs the hash iteration and freeing of items
2729 * on the hash. rcu_read_lock is too dangerous here.
2731 preempt_disable_notrace();
2732 hlist_for_each_entry_rcu(entry, n, hhd, node) {
2733 if (entry->ip == ip)
2734 entry->ops->func(ip, parent_ip, &entry->data);
2736 preempt_enable_notrace();
2739 static struct ftrace_ops trace_probe_ops __read_mostly =
2741 .func = function_trace_probe_call,
2744 static int ftrace_probe_registered;
2746 static void __enable_ftrace_function_probe(void)
2751 if (ftrace_probe_registered)
2754 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2755 struct hlist_head *hhd = &ftrace_func_hash[i];
2759 /* Nothing registered? */
2760 if (i == FTRACE_FUNC_HASHSIZE)
2763 ret = __register_ftrace_function(&trace_probe_ops);
2765 ret = ftrace_startup(&trace_probe_ops, 0);
2767 ftrace_probe_registered = 1;
2770 static void __disable_ftrace_function_probe(void)
2775 if (!ftrace_probe_registered)
2778 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2779 struct hlist_head *hhd = &ftrace_func_hash[i];
2784 /* no more funcs left */
2785 ret = __unregister_ftrace_function(&trace_probe_ops);
2787 ftrace_shutdown(&trace_probe_ops, 0);
2789 ftrace_probe_registered = 0;
2793 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
2795 struct ftrace_func_probe *entry =
2796 container_of(rhp, struct ftrace_func_probe, rcu);
2798 if (entry->ops->free)
2799 entry->ops->free(&entry->data);
2805 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2808 struct ftrace_func_probe *entry;
2809 struct ftrace_page *pg;
2810 struct dyn_ftrace *rec;
2816 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
2817 len = strlen(search);
2819 /* we do not support '!' for function probes */
2823 mutex_lock(&ftrace_lock);
2825 if (unlikely(ftrace_disabled))
2828 do_for_each_ftrace_rec(pg, rec) {
2830 if (!ftrace_match_record(rec, NULL, search, len, type))
2833 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2835 /* If we did not process any, then return error */
2846 * The caller might want to do something special
2847 * for each function we find. We call the callback
2848 * to give the caller an opportunity to do so.
2850 if (ops->callback) {
2851 if (ops->callback(rec->ip, &entry->data) < 0) {
2852 /* caller does not like this func */
2859 entry->ip = rec->ip;
2861 key = hash_long(entry->ip, FTRACE_HASH_BITS);
2862 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
2864 } while_for_each_ftrace_rec();
2865 __enable_ftrace_function_probe();
2868 mutex_unlock(&ftrace_lock);
2874 PROBE_TEST_FUNC = 1,
2879 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2880 void *data, int flags)
2882 struct ftrace_func_probe *entry;
2883 struct hlist_node *n, *tmp;
2884 char str[KSYM_SYMBOL_LEN];
2885 int type = MATCH_FULL;
2889 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
2894 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
2895 len = strlen(search);
2897 /* we do not support '!' for function probes */
2902 mutex_lock(&ftrace_lock);
2903 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2904 struct hlist_head *hhd = &ftrace_func_hash[i];
2906 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
2908 /* break up if statements for readability */
2909 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
2912 if ((flags & PROBE_TEST_DATA) && entry->data != data)
2915 /* do this last, since it is the most expensive */
2917 kallsyms_lookup(entry->ip, NULL, NULL,
2919 if (!ftrace_match(str, glob, len, type))
2923 hlist_del(&entry->node);
2924 call_rcu(&entry->rcu, ftrace_free_entry_rcu);
2927 __disable_ftrace_function_probe();
2928 mutex_unlock(&ftrace_lock);
2932 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2935 __unregister_ftrace_function_probe(glob, ops, data,
2936 PROBE_TEST_FUNC | PROBE_TEST_DATA);
2940 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
2942 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
2945 void unregister_ftrace_function_probe_all(char *glob)
2947 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
2950 static LIST_HEAD(ftrace_commands);
2951 static DEFINE_MUTEX(ftrace_cmd_mutex);
2953 int register_ftrace_command(struct ftrace_func_command *cmd)
2955 struct ftrace_func_command *p;
2958 mutex_lock(&ftrace_cmd_mutex);
2959 list_for_each_entry(p, &ftrace_commands, list) {
2960 if (strcmp(cmd->name, p->name) == 0) {
2965 list_add(&cmd->list, &ftrace_commands);
2967 mutex_unlock(&ftrace_cmd_mutex);
2972 int unregister_ftrace_command(struct ftrace_func_command *cmd)
2974 struct ftrace_func_command *p, *n;
2977 mutex_lock(&ftrace_cmd_mutex);
2978 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
2979 if (strcmp(cmd->name, p->name) == 0) {
2981 list_del_init(&p->list);
2986 mutex_unlock(&ftrace_cmd_mutex);
2991 static int ftrace_process_regex(struct ftrace_hash *hash,
2992 char *buff, int len, int enable)
2994 char *func, *command, *next = buff;
2995 struct ftrace_func_command *p;
2998 func = strsep(&next, ":");
3001 ret = ftrace_match_records(hash, func, len);
3011 command = strsep(&next, ":");
3013 mutex_lock(&ftrace_cmd_mutex);
3014 list_for_each_entry(p, &ftrace_commands, list) {
3015 if (strcmp(p->name, command) == 0) {
3016 ret = p->func(hash, func, command, next, enable);
3021 mutex_unlock(&ftrace_cmd_mutex);
3027 ftrace_regex_write(struct file *file, const char __user *ubuf,
3028 size_t cnt, loff_t *ppos, int enable)
3030 struct ftrace_iterator *iter;
3031 struct trace_parser *parser;
3037 mutex_lock(&ftrace_regex_lock);
3040 if (unlikely(ftrace_disabled))
3043 if (file->f_mode & FMODE_READ) {
3044 struct seq_file *m = file->private_data;
3047 iter = file->private_data;
3049 parser = &iter->parser;
3050 read = trace_get_user(parser, ubuf, cnt, ppos);
3052 if (read >= 0 && trace_parser_loaded(parser) &&
3053 !trace_parser_cont(parser)) {
3054 ret = ftrace_process_regex(iter->hash, parser->buffer,
3055 parser->idx, enable);
3056 trace_parser_clear(parser);
3063 mutex_unlock(&ftrace_regex_lock);
3069 ftrace_filter_write(struct file *file, const char __user *ubuf,
3070 size_t cnt, loff_t *ppos)
3072 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
3076 ftrace_notrace_write(struct file *file, const char __user *ubuf,
3077 size_t cnt, loff_t *ppos)
3079 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
3083 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
3084 int reset, int enable)
3086 struct ftrace_hash **orig_hash;
3087 struct ftrace_hash *hash;
3090 /* All global ops uses the global ops filters */
3091 if (ops->flags & FTRACE_OPS_FL_GLOBAL)
3094 if (unlikely(ftrace_disabled))
3098 orig_hash = &ops->filter_hash;
3100 orig_hash = &ops->notrace_hash;
3102 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3106 mutex_lock(&ftrace_regex_lock);
3108 ftrace_filter_reset(hash);
3110 ftrace_match_records(hash, buf, len);
3112 mutex_lock(&ftrace_lock);
3113 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3114 if (!ret && ops->flags & FTRACE_OPS_FL_ENABLED
3116 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3118 mutex_unlock(&ftrace_lock);
3120 mutex_unlock(&ftrace_regex_lock);
3122 free_ftrace_hash(hash);
3127 * ftrace_set_filter - set a function to filter on in ftrace
3128 * @ops - the ops to set the filter with
3129 * @buf - the string that holds the function filter text.
3130 * @len - the length of the string.
3131 * @reset - non zero to reset all filters before applying this filter.
3133 * Filters denote which functions should be enabled when tracing is enabled.
3134 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3136 void ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
3139 ftrace_set_regex(ops, buf, len, reset, 1);
3141 EXPORT_SYMBOL_GPL(ftrace_set_filter);
3144 * ftrace_set_notrace - set a function to not trace in ftrace
3145 * @ops - the ops to set the notrace filter with
3146 * @buf - the string that holds the function notrace text.
3147 * @len - the length of the string.
3148 * @reset - non zero to reset all filters before applying this filter.
3150 * Notrace Filters denote which functions should not be enabled when tracing
3151 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3154 void ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
3157 ftrace_set_regex(ops, buf, len, reset, 0);
3159 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
3161 * ftrace_set_filter - set a function to filter on in ftrace
3162 * @ops - the ops to set the filter with
3163 * @buf - the string that holds the function filter text.
3164 * @len - the length of the string.
3165 * @reset - non zero to reset all filters before applying this filter.
3167 * Filters denote which functions should be enabled when tracing is enabled.
3168 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3170 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
3172 ftrace_set_regex(&global_ops, buf, len, reset, 1);
3174 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
3177 * ftrace_set_notrace - set a function to not trace in ftrace
3178 * @ops - the ops to set the notrace filter with
3179 * @buf - the string that holds the function notrace text.
3180 * @len - the length of the string.
3181 * @reset - non zero to reset all filters before applying this filter.
3183 * Notrace Filters denote which functions should not be enabled when tracing
3184 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3187 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
3189 ftrace_set_regex(&global_ops, buf, len, reset, 0);
3191 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
3194 * command line interface to allow users to set filters on boot up.
3196 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
3197 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
3198 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
3200 static int __init set_ftrace_notrace(char *str)
3202 strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
3205 __setup("ftrace_notrace=", set_ftrace_notrace);
3207 static int __init set_ftrace_filter(char *str)
3209 strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
3212 __setup("ftrace_filter=", set_ftrace_filter);
3214 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3215 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
3216 static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
3218 static int __init set_graph_function(char *str)
3220 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
3223 __setup("ftrace_graph_filter=", set_graph_function);
3225 static void __init set_ftrace_early_graph(char *buf)
3231 func = strsep(&buf, ",");
3232 /* we allow only one expression at a time */
3233 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3236 printk(KERN_DEBUG "ftrace: function %s not "
3237 "traceable\n", func);
3240 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3243 set_ftrace_early_filter(struct ftrace_ops *ops, char *buf, int enable)
3248 func = strsep(&buf, ",");
3249 ftrace_set_regex(ops, func, strlen(func), 0, enable);
3253 static void __init set_ftrace_early_filters(void)
3255 if (ftrace_filter_buf[0])
3256 set_ftrace_early_filter(&global_ops, ftrace_filter_buf, 1);
3257 if (ftrace_notrace_buf[0])
3258 set_ftrace_early_filter(&global_ops, ftrace_notrace_buf, 0);
3259 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3260 if (ftrace_graph_buf[0])
3261 set_ftrace_early_graph(ftrace_graph_buf);
3262 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3266 ftrace_regex_release(struct inode *inode, struct file *file)
3268 struct seq_file *m = (struct seq_file *)file->private_data;
3269 struct ftrace_iterator *iter;
3270 struct ftrace_hash **orig_hash;
3271 struct trace_parser *parser;
3275 mutex_lock(&ftrace_regex_lock);
3276 if (file->f_mode & FMODE_READ) {
3279 seq_release(inode, file);
3281 iter = file->private_data;
3283 parser = &iter->parser;
3284 if (trace_parser_loaded(parser)) {
3285 parser->buffer[parser->idx] = 0;
3286 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
3289 trace_parser_put(parser);
3291 if (file->f_mode & FMODE_WRITE) {
3292 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
3295 orig_hash = &iter->ops->filter_hash;
3297 orig_hash = &iter->ops->notrace_hash;
3299 mutex_lock(&ftrace_lock);
3300 ret = ftrace_hash_move(iter->ops, filter_hash,
3301 orig_hash, iter->hash);
3302 if (!ret && (iter->ops->flags & FTRACE_OPS_FL_ENABLED)
3304 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3306 mutex_unlock(&ftrace_lock);
3308 free_ftrace_hash(iter->hash);
3311 mutex_unlock(&ftrace_regex_lock);
3315 static const struct file_operations ftrace_avail_fops = {
3316 .open = ftrace_avail_open,
3318 .llseek = seq_lseek,
3319 .release = seq_release_private,
3322 static const struct file_operations ftrace_enabled_fops = {
3323 .open = ftrace_enabled_open,
3325 .llseek = seq_lseek,
3326 .release = seq_release_private,
3329 static const struct file_operations ftrace_filter_fops = {
3330 .open = ftrace_filter_open,
3332 .write = ftrace_filter_write,
3333 .llseek = ftrace_regex_lseek,
3334 .release = ftrace_regex_release,
3337 static const struct file_operations ftrace_notrace_fops = {
3338 .open = ftrace_notrace_open,
3340 .write = ftrace_notrace_write,
3341 .llseek = ftrace_regex_lseek,
3342 .release = ftrace_regex_release,
3345 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3347 static DEFINE_MUTEX(graph_lock);
3349 int ftrace_graph_count;
3350 int ftrace_graph_filter_enabled;
3351 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
3354 __g_next(struct seq_file *m, loff_t *pos)
3356 if (*pos >= ftrace_graph_count)
3358 return &ftrace_graph_funcs[*pos];
3362 g_next(struct seq_file *m, void *v, loff_t *pos)
3365 return __g_next(m, pos);
3368 static void *g_start(struct seq_file *m, loff_t *pos)
3370 mutex_lock(&graph_lock);
3372 /* Nothing, tell g_show to print all functions are enabled */
3373 if (!ftrace_graph_filter_enabled && !*pos)
3376 return __g_next(m, pos);
3379 static void g_stop(struct seq_file *m, void *p)
3381 mutex_unlock(&graph_lock);
3384 static int g_show(struct seq_file *m, void *v)
3386 unsigned long *ptr = v;
3391 if (ptr == (unsigned long *)1) {
3392 seq_printf(m, "#### all functions enabled ####\n");
3396 seq_printf(m, "%ps\n", (void *)*ptr);
3401 static const struct seq_operations ftrace_graph_seq_ops = {
3409 ftrace_graph_open(struct inode *inode, struct file *file)
3413 if (unlikely(ftrace_disabled))
3416 mutex_lock(&graph_lock);
3417 if ((file->f_mode & FMODE_WRITE) &&
3418 (file->f_flags & O_TRUNC)) {
3419 ftrace_graph_filter_enabled = 0;
3420 ftrace_graph_count = 0;
3421 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
3423 mutex_unlock(&graph_lock);
3425 if (file->f_mode & FMODE_READ)
3426 ret = seq_open(file, &ftrace_graph_seq_ops);
3432 ftrace_graph_release(struct inode *inode, struct file *file)
3434 if (file->f_mode & FMODE_READ)
3435 seq_release(inode, file);
3440 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
3442 struct dyn_ftrace *rec;
3443 struct ftrace_page *pg;
3452 type = filter_parse_regex(buffer, strlen(buffer), &search, ¬);
3453 if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
3456 search_len = strlen(search);
3458 mutex_lock(&ftrace_lock);
3460 if (unlikely(ftrace_disabled)) {
3461 mutex_unlock(&ftrace_lock);
3465 do_for_each_ftrace_rec(pg, rec) {
3467 if (ftrace_match_record(rec, NULL, search, search_len, type)) {
3468 /* if it is in the array */
3470 for (i = 0; i < *idx; i++) {
3471 if (array[i] == rec->ip) {
3480 array[(*idx)++] = rec->ip;
3481 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
3486 array[i] = array[--(*idx)];
3492 } while_for_each_ftrace_rec();
3494 mutex_unlock(&ftrace_lock);
3499 ftrace_graph_filter_enabled = 1;
3504 ftrace_graph_write(struct file *file, const char __user *ubuf,
3505 size_t cnt, loff_t *ppos)
3507 struct trace_parser parser;
3513 mutex_lock(&graph_lock);
3515 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
3520 read = trace_get_user(&parser, ubuf, cnt, ppos);
3522 if (read >= 0 && trace_parser_loaded((&parser))) {
3523 parser.buffer[parser.idx] = 0;
3525 /* we allow only one expression at a time */
3526 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3535 trace_parser_put(&parser);
3537 mutex_unlock(&graph_lock);
3542 static const struct file_operations ftrace_graph_fops = {
3543 .open = ftrace_graph_open,
3545 .write = ftrace_graph_write,
3546 .release = ftrace_graph_release,
3547 .llseek = seq_lseek,
3549 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3551 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
3554 trace_create_file("available_filter_functions", 0444,
3555 d_tracer, NULL, &ftrace_avail_fops);
3557 trace_create_file("enabled_functions", 0444,
3558 d_tracer, NULL, &ftrace_enabled_fops);
3560 trace_create_file("set_ftrace_filter", 0644, d_tracer,
3561 NULL, &ftrace_filter_fops);
3563 trace_create_file("set_ftrace_notrace", 0644, d_tracer,
3564 NULL, &ftrace_notrace_fops);
3566 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3567 trace_create_file("set_graph_function", 0444, d_tracer,
3569 &ftrace_graph_fops);
3570 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3575 static int ftrace_process_locs(struct module *mod,
3576 unsigned long *start,
3579 struct ftrace_page *pg;
3580 unsigned long count;
3583 unsigned long flags = 0; /* Shut up gcc */
3586 count = end - start;
3591 pg = ftrace_allocate_pages(count);
3595 mutex_lock(&ftrace_lock);
3598 * Core and each module needs their own pages, as
3599 * modules will free them when they are removed.
3600 * Force a new page to be allocated for modules.
3603 WARN_ON(ftrace_pages || ftrace_pages_start);
3604 /* First initialization */
3605 ftrace_pages = ftrace_pages_start = pg;
3610 if (WARN_ON(ftrace_pages->next)) {
3611 /* Hmm, we have free pages? */
3612 while (ftrace_pages->next)
3613 ftrace_pages = ftrace_pages->next;
3616 ftrace_pages->next = pg;
3622 addr = ftrace_call_adjust(*p++);
3624 * Some architecture linkers will pad between
3625 * the different mcount_loc sections of different
3626 * object files to satisfy alignments.
3627 * Skip any NULL pointers.
3631 if (!ftrace_record_ip(addr))
3636 * We only need to disable interrupts on start up
3637 * because we are modifying code that an interrupt
3638 * may execute, and the modification is not atomic.
3639 * But for modules, nothing runs the code we modify
3640 * until we are finished with it, and there's no
3641 * reason to cause large interrupt latencies while we do it.
3644 local_irq_save(flags);
3645 ftrace_update_code(mod);
3647 local_irq_restore(flags);
3650 mutex_unlock(&ftrace_lock);
3655 #ifdef CONFIG_MODULES
3657 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
3659 void ftrace_release_mod(struct module *mod)
3661 struct dyn_ftrace *rec;
3662 struct ftrace_page **last_pg;
3663 struct ftrace_page *pg;
3666 mutex_lock(&ftrace_lock);
3668 if (ftrace_disabled)
3672 * Each module has its own ftrace_pages, remove
3673 * them from the list.
3675 last_pg = &ftrace_pages_start;
3676 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
3677 rec = &pg->records[0];
3678 if (within_module_core(rec->ip, mod)) {
3680 * As core pages are first, the first
3681 * page should never be a module page.
3683 if (WARN_ON(pg == ftrace_pages_start))
3686 /* Check if we are deleting the last page */
3687 if (pg == ftrace_pages)
3688 ftrace_pages = next_to_ftrace_page(last_pg);
3690 *last_pg = pg->next;
3691 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3692 free_pages((unsigned long)pg->records, order);
3695 last_pg = &pg->next;
3698 mutex_unlock(&ftrace_lock);
3701 static void ftrace_init_module(struct module *mod,
3702 unsigned long *start, unsigned long *end)
3704 if (ftrace_disabled || start == end)
3706 ftrace_process_locs(mod, start, end);
3709 static int ftrace_module_notify(struct notifier_block *self,
3710 unsigned long val, void *data)
3712 struct module *mod = data;
3715 case MODULE_STATE_COMING:
3716 ftrace_init_module(mod, mod->ftrace_callsites,
3717 mod->ftrace_callsites +
3718 mod->num_ftrace_callsites);
3720 case MODULE_STATE_GOING:
3721 ftrace_release_mod(mod);
3728 static int ftrace_module_notify(struct notifier_block *self,
3729 unsigned long val, void *data)
3733 #endif /* CONFIG_MODULES */
3735 struct notifier_block ftrace_module_nb = {
3736 .notifier_call = ftrace_module_notify,
3740 extern unsigned long __start_mcount_loc[];
3741 extern unsigned long __stop_mcount_loc[];
3743 void __init ftrace_init(void)
3745 unsigned long count, addr, flags;
3748 /* Keep the ftrace pointer to the stub */
3749 addr = (unsigned long)ftrace_stub;
3751 local_irq_save(flags);
3752 ftrace_dyn_arch_init(&addr);
3753 local_irq_restore(flags);
3755 /* ftrace_dyn_arch_init places the return code in addr */
3759 count = __stop_mcount_loc - __start_mcount_loc;
3761 ret = ftrace_dyn_table_alloc(count);
3765 last_ftrace_enabled = ftrace_enabled = 1;
3767 ret = ftrace_process_locs(NULL,
3771 ret = register_module_notifier(&ftrace_module_nb);
3773 pr_warning("Failed to register trace ftrace module notifier\n");
3775 set_ftrace_early_filters();
3779 ftrace_disabled = 1;
3784 static struct ftrace_ops global_ops = {
3785 .func = ftrace_stub,
3788 static int __init ftrace_nodyn_init(void)
3793 device_initcall(ftrace_nodyn_init);
3795 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
3796 static inline void ftrace_startup_enable(int command) { }
3797 /* Keep as macros so we do not need to define the commands */
3798 # define ftrace_startup(ops, command) \
3800 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
3803 # define ftrace_shutdown(ops, command) do { } while (0)
3804 # define ftrace_startup_sysctl() do { } while (0)
3805 # define ftrace_shutdown_sysctl() do { } while (0)
3808 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
3813 #endif /* CONFIG_DYNAMIC_FTRACE */
3816 ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
3818 struct ftrace_ops *op;
3820 if (unlikely(trace_recursion_test(TRACE_INTERNAL_BIT)))
3823 trace_recursion_set(TRACE_INTERNAL_BIT);
3825 * Some of the ops may be dynamically allocated,
3826 * they must be freed after a synchronize_sched().
3828 preempt_disable_notrace();
3829 op = rcu_dereference_raw(ftrace_ops_list);
3830 while (op != &ftrace_list_end) {
3831 if (ftrace_ops_test(op, ip))
3832 op->func(ip, parent_ip);
3833 op = rcu_dereference_raw(op->next);
3835 preempt_enable_notrace();
3836 trace_recursion_clear(TRACE_INTERNAL_BIT);
3839 static void clear_ftrace_swapper(void)
3841 struct task_struct *p;
3845 for_each_online_cpu(cpu) {
3847 clear_tsk_trace_trace(p);
3852 static void set_ftrace_swapper(void)
3854 struct task_struct *p;
3858 for_each_online_cpu(cpu) {
3860 set_tsk_trace_trace(p);
3865 static void clear_ftrace_pid(struct pid *pid)
3867 struct task_struct *p;
3870 do_each_pid_task(pid, PIDTYPE_PID, p) {
3871 clear_tsk_trace_trace(p);
3872 } while_each_pid_task(pid, PIDTYPE_PID, p);
3878 static void set_ftrace_pid(struct pid *pid)
3880 struct task_struct *p;
3883 do_each_pid_task(pid, PIDTYPE_PID, p) {
3884 set_tsk_trace_trace(p);
3885 } while_each_pid_task(pid, PIDTYPE_PID, p);
3889 static void clear_ftrace_pid_task(struct pid *pid)
3891 if (pid == ftrace_swapper_pid)
3892 clear_ftrace_swapper();
3894 clear_ftrace_pid(pid);
3897 static void set_ftrace_pid_task(struct pid *pid)
3899 if (pid == ftrace_swapper_pid)
3900 set_ftrace_swapper();
3902 set_ftrace_pid(pid);
3905 static int ftrace_pid_add(int p)
3908 struct ftrace_pid *fpid;
3911 mutex_lock(&ftrace_lock);
3914 pid = ftrace_swapper_pid;
3916 pid = find_get_pid(p);
3923 list_for_each_entry(fpid, &ftrace_pids, list)
3924 if (fpid->pid == pid)
3929 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
3933 list_add(&fpid->list, &ftrace_pids);
3936 set_ftrace_pid_task(pid);
3938 ftrace_update_pid_func();
3939 ftrace_startup_enable(0);
3941 mutex_unlock(&ftrace_lock);
3945 if (pid != ftrace_swapper_pid)
3949 mutex_unlock(&ftrace_lock);
3953 static void ftrace_pid_reset(void)
3955 struct ftrace_pid *fpid, *safe;
3957 mutex_lock(&ftrace_lock);
3958 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
3959 struct pid *pid = fpid->pid;
3961 clear_ftrace_pid_task(pid);
3963 list_del(&fpid->list);
3967 ftrace_update_pid_func();
3968 ftrace_startup_enable(0);
3970 mutex_unlock(&ftrace_lock);
3973 static void *fpid_start(struct seq_file *m, loff_t *pos)
3975 mutex_lock(&ftrace_lock);
3977 if (list_empty(&ftrace_pids) && (!*pos))
3980 return seq_list_start(&ftrace_pids, *pos);
3983 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
3988 return seq_list_next(v, &ftrace_pids, pos);
3991 static void fpid_stop(struct seq_file *m, void *p)
3993 mutex_unlock(&ftrace_lock);
3996 static int fpid_show(struct seq_file *m, void *v)
3998 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
4000 if (v == (void *)1) {
4001 seq_printf(m, "no pid\n");
4005 if (fpid->pid == ftrace_swapper_pid)
4006 seq_printf(m, "swapper tasks\n");
4008 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
4013 static const struct seq_operations ftrace_pid_sops = {
4014 .start = fpid_start,
4021 ftrace_pid_open(struct inode *inode, struct file *file)
4025 if ((file->f_mode & FMODE_WRITE) &&
4026 (file->f_flags & O_TRUNC))
4029 if (file->f_mode & FMODE_READ)
4030 ret = seq_open(file, &ftrace_pid_sops);
4036 ftrace_pid_write(struct file *filp, const char __user *ubuf,
4037 size_t cnt, loff_t *ppos)
4043 if (cnt >= sizeof(buf))
4046 if (copy_from_user(&buf, ubuf, cnt))
4052 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
4053 * to clean the filter quietly.
4055 tmp = strstrip(buf);
4056 if (strlen(tmp) == 0)
4059 ret = strict_strtol(tmp, 10, &val);
4063 ret = ftrace_pid_add(val);
4065 return ret ? ret : cnt;
4069 ftrace_pid_release(struct inode *inode, struct file *file)
4071 if (file->f_mode & FMODE_READ)
4072 seq_release(inode, file);
4077 static const struct file_operations ftrace_pid_fops = {
4078 .open = ftrace_pid_open,
4079 .write = ftrace_pid_write,
4081 .llseek = seq_lseek,
4082 .release = ftrace_pid_release,
4085 static __init int ftrace_init_debugfs(void)
4087 struct dentry *d_tracer;
4089 d_tracer = tracing_init_dentry();
4093 ftrace_init_dyn_debugfs(d_tracer);
4095 trace_create_file("set_ftrace_pid", 0644, d_tracer,
4096 NULL, &ftrace_pid_fops);
4098 ftrace_profile_debugfs(d_tracer);
4102 fs_initcall(ftrace_init_debugfs);
4105 * ftrace_kill - kill ftrace
4107 * This function should be used by panic code. It stops ftrace
4108 * but in a not so nice way. If you need to simply kill ftrace
4109 * from a non-atomic section, use ftrace_kill.
4111 void ftrace_kill(void)
4113 ftrace_disabled = 1;
4115 clear_ftrace_function();
4119 * Test if ftrace is dead or not.
4121 int ftrace_is_dead(void)
4123 return ftrace_disabled;
4127 * register_ftrace_function - register a function for profiling
4128 * @ops - ops structure that holds the function for profiling.
4130 * Register a function to be called by all functions in the
4133 * Note: @ops->func and all the functions it calls must be labeled
4134 * with "notrace", otherwise it will go into a
4137 int register_ftrace_function(struct ftrace_ops *ops)
4141 mutex_lock(&ftrace_lock);
4143 if (unlikely(ftrace_disabled))
4146 ret = __register_ftrace_function(ops);
4148 ret = ftrace_startup(ops, 0);
4152 mutex_unlock(&ftrace_lock);
4155 EXPORT_SYMBOL_GPL(register_ftrace_function);
4158 * unregister_ftrace_function - unregister a function for profiling.
4159 * @ops - ops structure that holds the function to unregister
4161 * Unregister a function that was added to be called by ftrace profiling.
4163 int unregister_ftrace_function(struct ftrace_ops *ops)
4167 mutex_lock(&ftrace_lock);
4168 ret = __unregister_ftrace_function(ops);
4170 ftrace_shutdown(ops, 0);
4171 mutex_unlock(&ftrace_lock);
4175 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
4178 ftrace_enable_sysctl(struct ctl_table *table, int write,
4179 void __user *buffer, size_t *lenp,
4184 mutex_lock(&ftrace_lock);
4186 if (unlikely(ftrace_disabled))
4189 ret = proc_dointvec(table, write, buffer, lenp, ppos);
4191 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
4194 last_ftrace_enabled = !!ftrace_enabled;
4196 if (ftrace_enabled) {
4198 ftrace_startup_sysctl();
4200 /* we are starting ftrace again */
4201 if (ftrace_ops_list != &ftrace_list_end) {
4202 if (ftrace_ops_list->next == &ftrace_list_end)
4203 ftrace_trace_function = ftrace_ops_list->func;
4205 ftrace_trace_function = ftrace_ops_list_func;
4209 /* stopping ftrace calls (just send to ftrace_stub) */
4210 ftrace_trace_function = ftrace_stub;
4212 ftrace_shutdown_sysctl();
4216 mutex_unlock(&ftrace_lock);
4220 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4222 static int ftrace_graph_active;
4223 static struct notifier_block ftrace_suspend_notifier;
4225 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
4230 /* The callbacks that hook a function */
4231 trace_func_graph_ret_t ftrace_graph_return =
4232 (trace_func_graph_ret_t)ftrace_stub;
4233 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
4235 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
4236 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
4240 unsigned long flags;
4241 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
4242 struct task_struct *g, *t;
4244 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
4245 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
4246 * sizeof(struct ftrace_ret_stack),
4248 if (!ret_stack_list[i]) {
4256 read_lock_irqsave(&tasklist_lock, flags);
4257 do_each_thread(g, t) {
4263 if (t->ret_stack == NULL) {
4264 atomic_set(&t->tracing_graph_pause, 0);
4265 atomic_set(&t->trace_overrun, 0);
4266 t->curr_ret_stack = -1;
4267 /* Make sure the tasks see the -1 first: */
4269 t->ret_stack = ret_stack_list[start++];
4271 } while_each_thread(g, t);
4274 read_unlock_irqrestore(&tasklist_lock, flags);
4276 for (i = start; i < end; i++)
4277 kfree(ret_stack_list[i]);
4282 ftrace_graph_probe_sched_switch(void *ignore,
4283 struct task_struct *prev, struct task_struct *next)
4285 unsigned long long timestamp;
4289 * Does the user want to count the time a function was asleep.
4290 * If so, do not update the time stamps.
4292 if (trace_flags & TRACE_ITER_SLEEP_TIME)
4295 timestamp = trace_clock_local();
4297 prev->ftrace_timestamp = timestamp;
4299 /* only process tasks that we timestamped */
4300 if (!next->ftrace_timestamp)
4304 * Update all the counters in next to make up for the
4305 * time next was sleeping.
4307 timestamp -= next->ftrace_timestamp;
4309 for (index = next->curr_ret_stack; index >= 0; index--)
4310 next->ret_stack[index].calltime += timestamp;
4313 /* Allocate a return stack for each task */
4314 static int start_graph_tracing(void)
4316 struct ftrace_ret_stack **ret_stack_list;
4319 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
4320 sizeof(struct ftrace_ret_stack *),
4323 if (!ret_stack_list)
4326 /* The cpu_boot init_task->ret_stack will never be freed */
4327 for_each_online_cpu(cpu) {
4328 if (!idle_task(cpu)->ret_stack)
4329 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
4333 ret = alloc_retstack_tasklist(ret_stack_list);
4334 } while (ret == -EAGAIN);
4337 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4339 pr_info("ftrace_graph: Couldn't activate tracepoint"
4340 " probe to kernel_sched_switch\n");
4343 kfree(ret_stack_list);
4348 * Hibernation protection.
4349 * The state of the current task is too much unstable during
4350 * suspend/restore to disk. We want to protect against that.
4353 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
4357 case PM_HIBERNATION_PREPARE:
4358 pause_graph_tracing();
4361 case PM_POST_HIBERNATION:
4362 unpause_graph_tracing();
4368 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
4369 trace_func_graph_ent_t entryfunc)
4373 mutex_lock(&ftrace_lock);
4375 /* we currently allow only one tracer registered at a time */
4376 if (ftrace_graph_active) {
4381 ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
4382 register_pm_notifier(&ftrace_suspend_notifier);
4384 ftrace_graph_active++;
4385 ret = start_graph_tracing();
4387 ftrace_graph_active--;
4391 ftrace_graph_return = retfunc;
4392 ftrace_graph_entry = entryfunc;
4394 ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET);
4397 mutex_unlock(&ftrace_lock);
4401 void unregister_ftrace_graph(void)
4403 mutex_lock(&ftrace_lock);
4405 if (unlikely(!ftrace_graph_active))
4408 ftrace_graph_active--;
4409 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
4410 ftrace_graph_entry = ftrace_graph_entry_stub;
4411 ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET);
4412 unregister_pm_notifier(&ftrace_suspend_notifier);
4413 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4416 mutex_unlock(&ftrace_lock);
4419 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
4422 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
4424 atomic_set(&t->tracing_graph_pause, 0);
4425 atomic_set(&t->trace_overrun, 0);
4426 t->ftrace_timestamp = 0;
4427 /* make curr_ret_stack visible before we add the ret_stack */
4429 t->ret_stack = ret_stack;
4433 * Allocate a return stack for the idle task. May be the first
4434 * time through, or it may be done by CPU hotplug online.
4436 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
4438 t->curr_ret_stack = -1;
4440 * The idle task has no parent, it either has its own
4441 * stack or no stack at all.
4444 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
4446 if (ftrace_graph_active) {
4447 struct ftrace_ret_stack *ret_stack;
4449 ret_stack = per_cpu(idle_ret_stack, cpu);
4451 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4452 * sizeof(struct ftrace_ret_stack),
4456 per_cpu(idle_ret_stack, cpu) = ret_stack;
4458 graph_init_task(t, ret_stack);
4462 /* Allocate a return stack for newly created task */
4463 void ftrace_graph_init_task(struct task_struct *t)
4465 /* Make sure we do not use the parent ret_stack */
4466 t->ret_stack = NULL;
4467 t->curr_ret_stack = -1;
4469 if (ftrace_graph_active) {
4470 struct ftrace_ret_stack *ret_stack;
4472 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4473 * sizeof(struct ftrace_ret_stack),
4477 graph_init_task(t, ret_stack);
4481 void ftrace_graph_exit_task(struct task_struct *t)
4483 struct ftrace_ret_stack *ret_stack = t->ret_stack;
4485 t->ret_stack = NULL;
4486 /* NULL must become visible to IRQs before we free it: */
4492 void ftrace_graph_stop(void)