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/kprobes.h>
26 #include <linux/ftrace.h>
27 #include <linux/sysctl.h>
28 #include <linux/ctype.h>
29 #include <linux/list.h>
30 #include <linux/hash.h>
32 #include <trace/sched.h>
34 #include <asm/ftrace.h>
36 #include "trace_output.h"
37 #include "trace_stat.h"
39 #define FTRACE_WARN_ON(cond) \
45 #define FTRACE_WARN_ON_ONCE(cond) \
47 if (WARN_ON_ONCE(cond)) \
51 /* hash bits for specific function selection */
52 #define FTRACE_HASH_BITS 7
53 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
55 /* ftrace_enabled is a method to turn ftrace on or off */
56 int ftrace_enabled __read_mostly;
57 static int last_ftrace_enabled;
59 /* Quick disabling of function tracer. */
60 int function_trace_stop;
63 * ftrace_disabled is set when an anomaly is discovered.
64 * ftrace_disabled is much stronger than ftrace_enabled.
66 static int ftrace_disabled __read_mostly;
68 static DEFINE_MUTEX(ftrace_lock);
70 static struct ftrace_ops ftrace_list_end __read_mostly =
75 static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
76 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
77 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
78 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
80 static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
82 struct ftrace_ops *op = ftrace_list;
84 /* in case someone actually ports this to alpha! */
85 read_barrier_depends();
87 while (op != &ftrace_list_end) {
89 read_barrier_depends();
90 op->func(ip, parent_ip);
95 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
97 if (!test_tsk_trace_trace(current))
100 ftrace_pid_function(ip, parent_ip);
103 static void set_ftrace_pid_function(ftrace_func_t func)
105 /* do not set ftrace_pid_function to itself! */
106 if (func != ftrace_pid_func)
107 ftrace_pid_function = func;
111 * clear_ftrace_function - reset the ftrace function
113 * This NULLs the ftrace function and in essence stops
114 * tracing. There may be lag
116 void clear_ftrace_function(void)
118 ftrace_trace_function = ftrace_stub;
119 __ftrace_trace_function = ftrace_stub;
120 ftrace_pid_function = ftrace_stub;
123 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
125 * For those archs that do not test ftrace_trace_stop in their
126 * mcount call site, we need to do it from C.
128 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
130 if (function_trace_stop)
133 __ftrace_trace_function(ip, parent_ip);
137 static int __register_ftrace_function(struct ftrace_ops *ops)
139 ops->next = ftrace_list;
141 * We are entering ops into the ftrace_list but another
142 * CPU might be walking that list. We need to make sure
143 * the ops->next pointer is valid before another CPU sees
144 * the ops pointer included into the ftrace_list.
149 if (ftrace_enabled) {
152 if (ops->next == &ftrace_list_end)
155 func = ftrace_list_func;
157 if (ftrace_pid_trace) {
158 set_ftrace_pid_function(func);
159 func = ftrace_pid_func;
163 * For one func, simply call it directly.
164 * For more than one func, call the chain.
166 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
167 ftrace_trace_function = func;
169 __ftrace_trace_function = func;
170 ftrace_trace_function = ftrace_test_stop_func;
177 static int __unregister_ftrace_function(struct ftrace_ops *ops)
179 struct ftrace_ops **p;
182 * If we are removing the last function, then simply point
183 * to the ftrace_stub.
185 if (ftrace_list == ops && ops->next == &ftrace_list_end) {
186 ftrace_trace_function = ftrace_stub;
187 ftrace_list = &ftrace_list_end;
191 for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
200 if (ftrace_enabled) {
201 /* If we only have one func left, then call that directly */
202 if (ftrace_list->next == &ftrace_list_end) {
203 ftrace_func_t func = ftrace_list->func;
205 if (ftrace_pid_trace) {
206 set_ftrace_pid_function(func);
207 func = ftrace_pid_func;
209 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
210 ftrace_trace_function = func;
212 __ftrace_trace_function = func;
220 static void ftrace_update_pid_func(void)
224 if (ftrace_trace_function == ftrace_stub)
227 func = ftrace_trace_function;
229 if (ftrace_pid_trace) {
230 set_ftrace_pid_function(func);
231 func = ftrace_pid_func;
233 if (func == ftrace_pid_func)
234 func = ftrace_pid_function;
237 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
238 ftrace_trace_function = func;
240 __ftrace_trace_function = func;
244 #ifdef CONFIG_FUNCTION_PROFILER
245 struct ftrace_profile {
246 struct hlist_node node;
248 unsigned long counter;
249 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
250 unsigned long long time;
254 struct ftrace_profile_page {
255 struct ftrace_profile_page *next;
257 struct ftrace_profile records[];
260 struct ftrace_profile_stat {
262 struct hlist_head *hash;
263 struct ftrace_profile_page *pages;
264 struct ftrace_profile_page *start;
265 struct tracer_stat stat;
268 #define PROFILE_RECORDS_SIZE \
269 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
271 #define PROFILES_PER_PAGE \
272 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
274 static int ftrace_profile_bits __read_mostly;
275 static int ftrace_profile_enabled __read_mostly;
277 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
278 static DEFINE_MUTEX(ftrace_profile_lock);
280 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
282 #define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
285 function_stat_next(void *v, int idx)
287 struct ftrace_profile *rec = v;
288 struct ftrace_profile_page *pg;
290 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
294 if ((void *)rec >= (void *)&pg->records[pg->index]) {
298 rec = &pg->records[0];
306 static void *function_stat_start(struct tracer_stat *trace)
308 struct ftrace_profile_stat *stat =
309 container_of(trace, struct ftrace_profile_stat, stat);
311 if (!stat || !stat->start)
314 return function_stat_next(&stat->start->records[0], 0);
317 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
318 /* function graph compares on total time */
319 static int function_stat_cmp(void *p1, void *p2)
321 struct ftrace_profile *a = p1;
322 struct ftrace_profile *b = p2;
324 if (a->time < b->time)
326 if (a->time > b->time)
332 /* not function graph compares against hits */
333 static int function_stat_cmp(void *p1, void *p2)
335 struct ftrace_profile *a = p1;
336 struct ftrace_profile *b = p2;
338 if (a->counter < b->counter)
340 if (a->counter > b->counter)
347 static int function_stat_headers(struct seq_file *m)
349 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
350 seq_printf(m, " Function Hit Time\n"
351 " -------- --- ----\n");
353 seq_printf(m, " Function Hit\n"
359 static int function_stat_show(struct seq_file *m, void *v)
361 struct ftrace_profile *rec = v;
362 char str[KSYM_SYMBOL_LEN];
363 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
364 static struct trace_seq s;
365 static DEFINE_MUTEX(mutex);
369 trace_print_graph_duration(rec->time, &s);
372 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
373 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
375 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
377 trace_print_seq(m, &s);
378 mutex_unlock(&mutex);
385 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
387 struct ftrace_profile_page *pg;
389 pg = stat->pages = stat->start;
392 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
397 memset(stat->hash, 0,
398 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
401 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
403 struct ftrace_profile_page *pg;
406 /* If we already allocated, do nothing */
410 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
414 pg = stat->start = stat->pages;
416 /* allocate 10 more pages to start */
417 for (i = 0; i < 10; i++) {
418 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
420 * We only care about allocating profile_pages, if
421 * we failed to allocate here, hopefully we will allocate
432 static int ftrace_profile_init_cpu(int cpu)
434 struct ftrace_profile_stat *stat;
437 stat = &per_cpu(ftrace_profile_stats, cpu);
440 /* If the profile is already created, simply reset it */
441 ftrace_profile_reset(stat);
446 * We are profiling all functions, but usually only a few thousand
447 * functions are hit. We'll make a hash of 1024 items.
449 size = FTRACE_PROFILE_HASH_SIZE;
451 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
456 if (!ftrace_profile_bits) {
459 for (; size; size >>= 1)
460 ftrace_profile_bits++;
463 /* Preallocate a few pages */
464 if (ftrace_profile_pages_init(stat) < 0) {
473 static int ftrace_profile_init(void)
478 for_each_online_cpu(cpu) {
479 ret = ftrace_profile_init_cpu(cpu);
487 /* interrupts must be disabled */
488 static struct ftrace_profile *
489 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
491 struct ftrace_profile *rec;
492 struct hlist_head *hhd;
493 struct hlist_node *n;
496 key = hash_long(ip, ftrace_profile_bits);
497 hhd = &stat->hash[key];
499 if (hlist_empty(hhd))
502 hlist_for_each_entry_rcu(rec, n, hhd, node) {
510 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
511 struct ftrace_profile *rec)
515 key = hash_long(rec->ip, ftrace_profile_bits);
516 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
519 /* Interrupts must be disabled calling this */
520 static struct ftrace_profile *
521 ftrace_profile_alloc(struct ftrace_profile_stat *stat,
522 unsigned long ip, bool alloc_safe)
524 struct ftrace_profile *rec = NULL;
526 /* prevent recursion */
527 if (atomic_inc_return(&stat->disabled) != 1)
530 /* Try to always keep another page available */
531 if (!stat->pages->next && alloc_safe)
532 stat->pages->next = (void *)get_zeroed_page(GFP_ATOMIC);
535 * Try to find the function again since another
536 * task on another CPU could have added it
538 rec = ftrace_find_profiled_func(stat, ip);
542 if (stat->pages->index == PROFILES_PER_PAGE) {
543 if (!stat->pages->next)
545 stat->pages = stat->pages->next;
548 rec = &stat->pages->records[stat->pages->index++];
550 ftrace_add_profile(stat, rec);
553 atomic_dec(&stat->disabled);
559 * If we are not in an interrupt, or softirq and
560 * and interrupts are disabled and preemption is not enabled
561 * (not in a spinlock) then it should be safe to allocate memory.
563 static bool ftrace_safe_to_allocate(void)
565 return !in_interrupt() && irqs_disabled() && !preempt_count();
569 function_profile_call(unsigned long ip, unsigned long parent_ip)
571 struct ftrace_profile_stat *stat;
572 struct ftrace_profile *rec;
576 if (!ftrace_profile_enabled)
579 alloc_safe = ftrace_safe_to_allocate();
581 local_irq_save(flags);
583 stat = &__get_cpu_var(ftrace_profile_stats);
587 rec = ftrace_find_profiled_func(stat, ip);
589 rec = ftrace_profile_alloc(stat, ip, alloc_safe);
596 local_irq_restore(flags);
599 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
600 static int profile_graph_entry(struct ftrace_graph_ent *trace)
602 function_profile_call(trace->func, 0);
606 static void profile_graph_return(struct ftrace_graph_ret *trace)
608 struct ftrace_profile_stat *stat;
609 unsigned long long calltime;
610 struct ftrace_profile *rec;
613 local_irq_save(flags);
614 stat = &__get_cpu_var(ftrace_profile_stats);
618 calltime = trace->rettime - trace->calltime;
620 if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
623 index = trace->depth;
625 /* Append this call time to the parent time to subtract */
627 current->ret_stack[index - 1].subtime += calltime;
629 if (current->ret_stack[index].subtime < calltime)
630 calltime -= current->ret_stack[index].subtime;
635 rec = ftrace_find_profiled_func(stat, trace->func);
637 rec->time += calltime;
640 local_irq_restore(flags);
643 static int register_ftrace_profiler(void)
645 return register_ftrace_graph(&profile_graph_return,
646 &profile_graph_entry);
649 static void unregister_ftrace_profiler(void)
651 unregister_ftrace_graph();
654 static struct ftrace_ops ftrace_profile_ops __read_mostly =
656 .func = function_profile_call,
659 static int register_ftrace_profiler(void)
661 return register_ftrace_function(&ftrace_profile_ops);
664 static void unregister_ftrace_profiler(void)
666 unregister_ftrace_function(&ftrace_profile_ops);
668 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
671 ftrace_profile_write(struct file *filp, const char __user *ubuf,
672 size_t cnt, loff_t *ppos)
675 char buf[64]; /* big enough to hold a number */
678 if (cnt >= sizeof(buf))
681 if (copy_from_user(&buf, ubuf, cnt))
686 ret = strict_strtoul(buf, 10, &val);
692 mutex_lock(&ftrace_profile_lock);
693 if (ftrace_profile_enabled ^ val) {
695 ret = ftrace_profile_init();
701 ret = register_ftrace_profiler();
706 ftrace_profile_enabled = 1;
708 ftrace_profile_enabled = 0;
709 unregister_ftrace_profiler();
713 mutex_unlock(&ftrace_profile_lock);
721 ftrace_profile_read(struct file *filp, char __user *ubuf,
722 size_t cnt, loff_t *ppos)
724 char buf[64]; /* big enough to hold a number */
727 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
728 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
731 static const struct file_operations ftrace_profile_fops = {
732 .open = tracing_open_generic,
733 .read = ftrace_profile_read,
734 .write = ftrace_profile_write,
737 /* used to initialize the real stat files */
738 static struct tracer_stat function_stats __initdata = {
740 .stat_start = function_stat_start,
741 .stat_next = function_stat_next,
742 .stat_cmp = function_stat_cmp,
743 .stat_headers = function_stat_headers,
744 .stat_show = function_stat_show
747 static void ftrace_profile_debugfs(struct dentry *d_tracer)
749 struct ftrace_profile_stat *stat;
750 struct dentry *entry;
755 for_each_possible_cpu(cpu) {
756 stat = &per_cpu(ftrace_profile_stats, cpu);
758 /* allocate enough for function name + cpu number */
759 name = kmalloc(32, GFP_KERNEL);
762 * The files created are permanent, if something happens
763 * we still do not free memory.
767 "Could not allocate stat file for cpu %d\n",
771 stat->stat = function_stats;
772 snprintf(name, 32, "function%d", cpu);
773 stat->stat.name = name;
774 ret = register_stat_tracer(&stat->stat);
777 "Could not register function stat for cpu %d\n",
784 entry = debugfs_create_file("function_profile_enabled", 0644,
785 d_tracer, NULL, &ftrace_profile_fops);
787 pr_warning("Could not create debugfs "
788 "'function_profile_enabled' entry\n");
791 #else /* CONFIG_FUNCTION_PROFILER */
792 static void ftrace_profile_debugfs(struct dentry *d_tracer)
795 #endif /* CONFIG_FUNCTION_PROFILER */
797 /* set when tracing only a pid */
798 struct pid *ftrace_pid_trace;
799 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
801 #ifdef CONFIG_DYNAMIC_FTRACE
803 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
804 # error Dynamic ftrace depends on MCOUNT_RECORD
807 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
809 struct ftrace_func_probe {
810 struct hlist_node node;
811 struct ftrace_probe_ops *ops;
819 FTRACE_ENABLE_CALLS = (1 << 0),
820 FTRACE_DISABLE_CALLS = (1 << 1),
821 FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
822 FTRACE_ENABLE_MCOUNT = (1 << 3),
823 FTRACE_DISABLE_MCOUNT = (1 << 4),
824 FTRACE_START_FUNC_RET = (1 << 5),
825 FTRACE_STOP_FUNC_RET = (1 << 6),
828 static int ftrace_filtered;
830 static struct dyn_ftrace *ftrace_new_addrs;
832 static DEFINE_MUTEX(ftrace_regex_lock);
835 struct ftrace_page *next;
837 struct dyn_ftrace records[];
840 #define ENTRIES_PER_PAGE \
841 ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
843 /* estimate from running different kernels */
844 #define NR_TO_INIT 10000
846 static struct ftrace_page *ftrace_pages_start;
847 static struct ftrace_page *ftrace_pages;
849 static struct dyn_ftrace *ftrace_free_records;
852 * This is a double for. Do not use 'break' to break out of the loop,
853 * you must use a goto.
855 #define do_for_each_ftrace_rec(pg, rec) \
856 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
858 for (_____i = 0; _____i < pg->index; _____i++) { \
859 rec = &pg->records[_____i];
861 #define while_for_each_ftrace_rec() \
865 #ifdef CONFIG_KPROBES
867 static int frozen_record_count;
869 static inline void freeze_record(struct dyn_ftrace *rec)
871 if (!(rec->flags & FTRACE_FL_FROZEN)) {
872 rec->flags |= FTRACE_FL_FROZEN;
873 frozen_record_count++;
877 static inline void unfreeze_record(struct dyn_ftrace *rec)
879 if (rec->flags & FTRACE_FL_FROZEN) {
880 rec->flags &= ~FTRACE_FL_FROZEN;
881 frozen_record_count--;
885 static inline int record_frozen(struct dyn_ftrace *rec)
887 return rec->flags & FTRACE_FL_FROZEN;
890 # define freeze_record(rec) ({ 0; })
891 # define unfreeze_record(rec) ({ 0; })
892 # define record_frozen(rec) ({ 0; })
893 #endif /* CONFIG_KPROBES */
895 static void ftrace_free_rec(struct dyn_ftrace *rec)
897 rec->freelist = ftrace_free_records;
898 ftrace_free_records = rec;
899 rec->flags |= FTRACE_FL_FREE;
902 void ftrace_release(void *start, unsigned long size)
904 struct dyn_ftrace *rec;
905 struct ftrace_page *pg;
906 unsigned long s = (unsigned long)start;
907 unsigned long e = s + size;
909 if (ftrace_disabled || !start)
912 mutex_lock(&ftrace_lock);
913 do_for_each_ftrace_rec(pg, rec) {
914 if ((rec->ip >= s) && (rec->ip < e) &&
915 !(rec->flags & FTRACE_FL_FREE))
916 ftrace_free_rec(rec);
917 } while_for_each_ftrace_rec();
918 mutex_unlock(&ftrace_lock);
921 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
923 struct dyn_ftrace *rec;
925 /* First check for freed records */
926 if (ftrace_free_records) {
927 rec = ftrace_free_records;
929 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
930 FTRACE_WARN_ON_ONCE(1);
931 ftrace_free_records = NULL;
935 ftrace_free_records = rec->freelist;
936 memset(rec, 0, sizeof(*rec));
940 if (ftrace_pages->index == ENTRIES_PER_PAGE) {
941 if (!ftrace_pages->next) {
942 /* allocate another page */
944 (void *)get_zeroed_page(GFP_KERNEL);
945 if (!ftrace_pages->next)
948 ftrace_pages = ftrace_pages->next;
951 return &ftrace_pages->records[ftrace_pages->index++];
954 static struct dyn_ftrace *
955 ftrace_record_ip(unsigned long ip)
957 struct dyn_ftrace *rec;
962 rec = ftrace_alloc_dyn_node(ip);
967 rec->newlist = ftrace_new_addrs;
968 ftrace_new_addrs = rec;
973 static void print_ip_ins(const char *fmt, unsigned char *p)
977 printk(KERN_CONT "%s", fmt);
979 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
980 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
983 static void ftrace_bug(int failed, unsigned long ip)
987 FTRACE_WARN_ON_ONCE(1);
988 pr_info("ftrace faulted on modifying ");
992 FTRACE_WARN_ON_ONCE(1);
993 pr_info("ftrace failed to modify ");
995 print_ip_ins(" actual: ", (unsigned char *)ip);
996 printk(KERN_CONT "\n");
999 FTRACE_WARN_ON_ONCE(1);
1000 pr_info("ftrace faulted on writing ");
1004 FTRACE_WARN_ON_ONCE(1);
1005 pr_info("ftrace faulted on unknown error ");
1012 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1014 unsigned long ftrace_addr;
1015 unsigned long ip, fl;
1017 ftrace_addr = (unsigned long)FTRACE_ADDR;
1022 * If this record is not to be traced and
1023 * it is not enabled then do nothing.
1025 * If this record is not to be traced and
1026 * it is enabled then disable it.
1029 if (rec->flags & FTRACE_FL_NOTRACE) {
1030 if (rec->flags & FTRACE_FL_ENABLED)
1031 rec->flags &= ~FTRACE_FL_ENABLED;
1035 } else if (ftrace_filtered && enable) {
1040 fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED);
1042 /* Record is filtered and enabled, do nothing */
1043 if (fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED))
1046 /* Record is not filtered or enabled, do nothing */
1050 /* Record is not filtered but enabled, disable it */
1051 if (fl == FTRACE_FL_ENABLED)
1052 rec->flags &= ~FTRACE_FL_ENABLED;
1054 /* Otherwise record is filtered but not enabled, enable it */
1055 rec->flags |= FTRACE_FL_ENABLED;
1057 /* Disable or not filtered */
1060 /* if record is enabled, do nothing */
1061 if (rec->flags & FTRACE_FL_ENABLED)
1064 rec->flags |= FTRACE_FL_ENABLED;
1068 /* if record is not enabled, do nothing */
1069 if (!(rec->flags & FTRACE_FL_ENABLED))
1072 rec->flags &= ~FTRACE_FL_ENABLED;
1076 if (rec->flags & FTRACE_FL_ENABLED)
1077 return ftrace_make_call(rec, ftrace_addr);
1079 return ftrace_make_nop(NULL, rec, ftrace_addr);
1082 static void ftrace_replace_code(int enable)
1084 struct dyn_ftrace *rec;
1085 struct ftrace_page *pg;
1088 do_for_each_ftrace_rec(pg, rec) {
1090 * Skip over free records, records that have
1091 * failed and not converted.
1093 if (rec->flags & FTRACE_FL_FREE ||
1094 rec->flags & FTRACE_FL_FAILED ||
1095 !(rec->flags & FTRACE_FL_CONVERTED))
1098 /* ignore updates to this record's mcount site */
1099 if (get_kprobe((void *)rec->ip)) {
1103 unfreeze_record(rec);
1106 failed = __ftrace_replace_code(rec, enable);
1108 rec->flags |= FTRACE_FL_FAILED;
1109 if ((system_state == SYSTEM_BOOTING) ||
1110 !core_kernel_text(rec->ip)) {
1111 ftrace_free_rec(rec);
1113 ftrace_bug(failed, rec->ip);
1114 /* Stop processing */
1118 } while_for_each_ftrace_rec();
1122 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1129 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1131 ftrace_bug(ret, ip);
1132 rec->flags |= FTRACE_FL_FAILED;
1139 * archs can override this function if they must do something
1140 * before the modifying code is performed.
1142 int __weak ftrace_arch_code_modify_prepare(void)
1148 * archs can override this function if they must do something
1149 * after the modifying code is performed.
1151 int __weak ftrace_arch_code_modify_post_process(void)
1156 static int __ftrace_modify_code(void *data)
1158 int *command = data;
1160 if (*command & FTRACE_ENABLE_CALLS)
1161 ftrace_replace_code(1);
1162 else if (*command & FTRACE_DISABLE_CALLS)
1163 ftrace_replace_code(0);
1165 if (*command & FTRACE_UPDATE_TRACE_FUNC)
1166 ftrace_update_ftrace_func(ftrace_trace_function);
1168 if (*command & FTRACE_START_FUNC_RET)
1169 ftrace_enable_ftrace_graph_caller();
1170 else if (*command & FTRACE_STOP_FUNC_RET)
1171 ftrace_disable_ftrace_graph_caller();
1176 static void ftrace_run_update_code(int command)
1180 ret = ftrace_arch_code_modify_prepare();
1181 FTRACE_WARN_ON(ret);
1185 stop_machine(__ftrace_modify_code, &command, NULL);
1187 ret = ftrace_arch_code_modify_post_process();
1188 FTRACE_WARN_ON(ret);
1191 static ftrace_func_t saved_ftrace_func;
1192 static int ftrace_start_up;
1194 static void ftrace_startup_enable(int command)
1196 if (saved_ftrace_func != ftrace_trace_function) {
1197 saved_ftrace_func = ftrace_trace_function;
1198 command |= FTRACE_UPDATE_TRACE_FUNC;
1201 if (!command || !ftrace_enabled)
1204 ftrace_run_update_code(command);
1207 static void ftrace_startup(int command)
1209 if (unlikely(ftrace_disabled))
1213 command |= FTRACE_ENABLE_CALLS;
1215 ftrace_startup_enable(command);
1218 static void ftrace_shutdown(int command)
1220 if (unlikely(ftrace_disabled))
1224 if (!ftrace_start_up)
1225 command |= FTRACE_DISABLE_CALLS;
1227 if (saved_ftrace_func != ftrace_trace_function) {
1228 saved_ftrace_func = ftrace_trace_function;
1229 command |= FTRACE_UPDATE_TRACE_FUNC;
1232 if (!command || !ftrace_enabled)
1235 ftrace_run_update_code(command);
1238 static void ftrace_startup_sysctl(void)
1240 int command = FTRACE_ENABLE_MCOUNT;
1242 if (unlikely(ftrace_disabled))
1245 /* Force update next time */
1246 saved_ftrace_func = NULL;
1247 /* ftrace_start_up is true if we want ftrace running */
1248 if (ftrace_start_up)
1249 command |= FTRACE_ENABLE_CALLS;
1251 ftrace_run_update_code(command);
1254 static void ftrace_shutdown_sysctl(void)
1256 int command = FTRACE_DISABLE_MCOUNT;
1258 if (unlikely(ftrace_disabled))
1261 /* ftrace_start_up is true if ftrace is running */
1262 if (ftrace_start_up)
1263 command |= FTRACE_DISABLE_CALLS;
1265 ftrace_run_update_code(command);
1268 static cycle_t ftrace_update_time;
1269 static unsigned long ftrace_update_cnt;
1270 unsigned long ftrace_update_tot_cnt;
1272 static int ftrace_update_code(struct module *mod)
1274 struct dyn_ftrace *p;
1275 cycle_t start, stop;
1277 start = ftrace_now(raw_smp_processor_id());
1278 ftrace_update_cnt = 0;
1280 while (ftrace_new_addrs) {
1282 /* If something went wrong, bail without enabling anything */
1283 if (unlikely(ftrace_disabled))
1286 p = ftrace_new_addrs;
1287 ftrace_new_addrs = p->newlist;
1290 /* convert record (i.e, patch mcount-call with NOP) */
1291 if (ftrace_code_disable(mod, p)) {
1292 p->flags |= FTRACE_FL_CONVERTED;
1293 ftrace_update_cnt++;
1298 stop = ftrace_now(raw_smp_processor_id());
1299 ftrace_update_time = stop - start;
1300 ftrace_update_tot_cnt += ftrace_update_cnt;
1305 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
1307 struct ftrace_page *pg;
1311 /* allocate a few pages */
1312 ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
1313 if (!ftrace_pages_start)
1317 * Allocate a few more pages.
1319 * TODO: have some parser search vmlinux before
1320 * final linking to find all calls to ftrace.
1322 * a) know how many pages to allocate.
1324 * b) set up the table then.
1326 * The dynamic code is still necessary for
1330 pg = ftrace_pages = ftrace_pages_start;
1332 cnt = num_to_init / ENTRIES_PER_PAGE;
1333 pr_info("ftrace: allocating %ld entries in %d pages\n",
1334 num_to_init, cnt + 1);
1336 for (i = 0; i < cnt; i++) {
1337 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
1339 /* If we fail, we'll try later anyway */
1350 FTRACE_ITER_FILTER = (1 << 0),
1351 FTRACE_ITER_CONT = (1 << 1),
1352 FTRACE_ITER_NOTRACE = (1 << 2),
1353 FTRACE_ITER_FAILURES = (1 << 3),
1354 FTRACE_ITER_PRINTALL = (1 << 4),
1355 FTRACE_ITER_HASH = (1 << 5),
1358 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
1360 struct ftrace_iterator {
1361 struct ftrace_page *pg;
1365 unsigned char buffer[FTRACE_BUFF_MAX+1];
1366 unsigned buffer_idx;
1371 t_hash_next(struct seq_file *m, void *v, loff_t *pos)
1373 struct ftrace_iterator *iter = m->private;
1374 struct hlist_node *hnd = v;
1375 struct hlist_head *hhd;
1377 WARN_ON(!(iter->flags & FTRACE_ITER_HASH));
1382 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
1385 hhd = &ftrace_func_hash[iter->hidx];
1387 if (hlist_empty(hhd)) {
1406 static void *t_hash_start(struct seq_file *m, loff_t *pos)
1408 struct ftrace_iterator *iter = m->private;
1411 iter->flags |= FTRACE_ITER_HASH;
1413 return t_hash_next(m, p, pos);
1416 static int t_hash_show(struct seq_file *m, void *v)
1418 struct ftrace_func_probe *rec;
1419 struct hlist_node *hnd = v;
1420 char str[KSYM_SYMBOL_LEN];
1422 rec = hlist_entry(hnd, struct ftrace_func_probe, node);
1424 if (rec->ops->print)
1425 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
1427 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1428 seq_printf(m, "%s:", str);
1430 kallsyms_lookup((unsigned long)rec->ops->func, NULL, NULL, NULL, str);
1431 seq_printf(m, "%s", str);
1434 seq_printf(m, ":%p", rec->data);
1441 t_next(struct seq_file *m, void *v, loff_t *pos)
1443 struct ftrace_iterator *iter = m->private;
1444 struct dyn_ftrace *rec = NULL;
1446 if (iter->flags & FTRACE_ITER_HASH)
1447 return t_hash_next(m, v, pos);
1451 if (iter->flags & FTRACE_ITER_PRINTALL)
1455 if (iter->idx >= iter->pg->index) {
1456 if (iter->pg->next) {
1457 iter->pg = iter->pg->next;
1464 rec = &iter->pg->records[iter->idx++];
1465 if ((rec->flags & FTRACE_FL_FREE) ||
1467 (!(iter->flags & FTRACE_ITER_FAILURES) &&
1468 (rec->flags & FTRACE_FL_FAILED)) ||
1470 ((iter->flags & FTRACE_ITER_FAILURES) &&
1471 !(rec->flags & FTRACE_FL_FAILED)) ||
1473 ((iter->flags & FTRACE_ITER_FILTER) &&
1474 !(rec->flags & FTRACE_FL_FILTER)) ||
1476 ((iter->flags & FTRACE_ITER_NOTRACE) &&
1477 !(rec->flags & FTRACE_FL_NOTRACE))) {
1486 static void *t_start(struct seq_file *m, loff_t *pos)
1488 struct ftrace_iterator *iter = m->private;
1491 mutex_lock(&ftrace_lock);
1493 * For set_ftrace_filter reading, if we have the filter
1494 * off, we can short cut and just print out that all
1495 * functions are enabled.
1497 if (iter->flags & FTRACE_ITER_FILTER && !ftrace_filtered) {
1499 return t_hash_start(m, pos);
1500 iter->flags |= FTRACE_ITER_PRINTALL;
1505 if (iter->flags & FTRACE_ITER_HASH)
1506 return t_hash_start(m, pos);
1515 p = t_next(m, p, pos);
1518 return t_hash_start(m, pos);
1523 static void t_stop(struct seq_file *m, void *p)
1525 mutex_unlock(&ftrace_lock);
1528 static int t_show(struct seq_file *m, void *v)
1530 struct ftrace_iterator *iter = m->private;
1531 struct dyn_ftrace *rec = v;
1532 char str[KSYM_SYMBOL_LEN];
1534 if (iter->flags & FTRACE_ITER_HASH)
1535 return t_hash_show(m, v);
1537 if (iter->flags & FTRACE_ITER_PRINTALL) {
1538 seq_printf(m, "#### all functions enabled ####\n");
1545 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1547 seq_printf(m, "%s\n", str);
1552 static struct seq_operations show_ftrace_seq_ops = {
1560 ftrace_avail_open(struct inode *inode, struct file *file)
1562 struct ftrace_iterator *iter;
1565 if (unlikely(ftrace_disabled))
1568 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1572 iter->pg = ftrace_pages_start;
1574 ret = seq_open(file, &show_ftrace_seq_ops);
1576 struct seq_file *m = file->private_data;
1586 int ftrace_avail_release(struct inode *inode, struct file *file)
1588 struct seq_file *m = (struct seq_file *)file->private_data;
1589 struct ftrace_iterator *iter = m->private;
1591 seq_release(inode, file);
1598 ftrace_failures_open(struct inode *inode, struct file *file)
1602 struct ftrace_iterator *iter;
1604 ret = ftrace_avail_open(inode, file);
1606 m = (struct seq_file *)file->private_data;
1607 iter = (struct ftrace_iterator *)m->private;
1608 iter->flags = FTRACE_ITER_FAILURES;
1615 static void ftrace_filter_reset(int enable)
1617 struct ftrace_page *pg;
1618 struct dyn_ftrace *rec;
1619 unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1621 mutex_lock(&ftrace_lock);
1623 ftrace_filtered = 0;
1624 do_for_each_ftrace_rec(pg, rec) {
1625 if (rec->flags & FTRACE_FL_FAILED)
1627 rec->flags &= ~type;
1628 } while_for_each_ftrace_rec();
1629 mutex_unlock(&ftrace_lock);
1633 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
1635 struct ftrace_iterator *iter;
1638 if (unlikely(ftrace_disabled))
1641 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1645 mutex_lock(&ftrace_regex_lock);
1646 if ((file->f_mode & FMODE_WRITE) &&
1647 !(file->f_flags & O_APPEND))
1648 ftrace_filter_reset(enable);
1650 if (file->f_mode & FMODE_READ) {
1651 iter->pg = ftrace_pages_start;
1652 iter->flags = enable ? FTRACE_ITER_FILTER :
1653 FTRACE_ITER_NOTRACE;
1655 ret = seq_open(file, &show_ftrace_seq_ops);
1657 struct seq_file *m = file->private_data;
1662 file->private_data = iter;
1663 mutex_unlock(&ftrace_regex_lock);
1669 ftrace_filter_open(struct inode *inode, struct file *file)
1671 return ftrace_regex_open(inode, file, 1);
1675 ftrace_notrace_open(struct inode *inode, struct file *file)
1677 return ftrace_regex_open(inode, file, 0);
1681 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1685 if (file->f_mode & FMODE_READ)
1686 ret = seq_lseek(file, offset, origin);
1688 file->f_pos = ret = 1;
1701 * (static function - no need for kernel doc)
1703 * Pass in a buffer containing a glob and this function will
1704 * set search to point to the search part of the buffer and
1705 * return the type of search it is (see enum above).
1706 * This does modify buff.
1708 * Returns enum type.
1709 * search returns the pointer to use for comparison.
1710 * not returns 1 if buff started with a '!'
1714 ftrace_setup_glob(char *buff, int len, char **search, int *not)
1716 int type = MATCH_FULL;
1719 if (buff[0] == '!') {
1728 for (i = 0; i < len; i++) {
1729 if (buff[i] == '*') {
1732 type = MATCH_END_ONLY;
1734 if (type == MATCH_END_ONLY)
1735 type = MATCH_MIDDLE_ONLY;
1737 type = MATCH_FRONT_ONLY;
1747 static int ftrace_match(char *str, char *regex, int len, int type)
1754 if (strcmp(str, regex) == 0)
1757 case MATCH_FRONT_ONLY:
1758 if (strncmp(str, regex, len) == 0)
1761 case MATCH_MIDDLE_ONLY:
1762 if (strstr(str, regex))
1765 case MATCH_END_ONLY:
1766 ptr = strstr(str, regex);
1767 if (ptr && (ptr[len] == 0))
1776 ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
1778 char str[KSYM_SYMBOL_LEN];
1780 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1781 return ftrace_match(str, regex, len, type);
1784 static void ftrace_match_records(char *buff, int len, int enable)
1786 unsigned int search_len;
1787 struct ftrace_page *pg;
1788 struct dyn_ftrace *rec;
1794 flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1795 type = ftrace_setup_glob(buff, len, &search, ¬);
1797 search_len = strlen(search);
1799 mutex_lock(&ftrace_lock);
1800 do_for_each_ftrace_rec(pg, rec) {
1802 if (rec->flags & FTRACE_FL_FAILED)
1805 if (ftrace_match_record(rec, search, search_len, type)) {
1807 rec->flags &= ~flag;
1812 * Only enable filtering if we have a function that
1815 if (enable && (rec->flags & FTRACE_FL_FILTER))
1816 ftrace_filtered = 1;
1817 } while_for_each_ftrace_rec();
1818 mutex_unlock(&ftrace_lock);
1822 ftrace_match_module_record(struct dyn_ftrace *rec, char *mod,
1823 char *regex, int len, int type)
1825 char str[KSYM_SYMBOL_LEN];
1828 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
1830 if (!modname || strcmp(modname, mod))
1833 /* blank search means to match all funcs in the mod */
1835 return ftrace_match(str, regex, len, type);
1840 static void ftrace_match_module_records(char *buff, char *mod, int enable)
1842 unsigned search_len = 0;
1843 struct ftrace_page *pg;
1844 struct dyn_ftrace *rec;
1845 int type = MATCH_FULL;
1846 char *search = buff;
1850 flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1852 /* blank or '*' mean the same */
1853 if (strcmp(buff, "*") == 0)
1856 /* handle the case of 'dont filter this module' */
1857 if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
1863 type = ftrace_setup_glob(buff, strlen(buff), &search, ¬);
1864 search_len = strlen(search);
1867 mutex_lock(&ftrace_lock);
1868 do_for_each_ftrace_rec(pg, rec) {
1870 if (rec->flags & FTRACE_FL_FAILED)
1873 if (ftrace_match_module_record(rec, mod,
1874 search, search_len, type)) {
1876 rec->flags &= ~flag;
1880 if (enable && (rec->flags & FTRACE_FL_FILTER))
1881 ftrace_filtered = 1;
1883 } while_for_each_ftrace_rec();
1884 mutex_unlock(&ftrace_lock);
1888 * We register the module command as a template to show others how
1889 * to register the a command as well.
1893 ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
1898 * cmd == 'mod' because we only registered this func
1899 * for the 'mod' ftrace_func_command.
1900 * But if you register one func with multiple commands,
1901 * you can tell which command was used by the cmd
1905 /* we must have a module name */
1909 mod = strsep(¶m, ":");
1913 ftrace_match_module_records(func, mod, enable);
1917 static struct ftrace_func_command ftrace_mod_cmd = {
1919 .func = ftrace_mod_callback,
1922 static int __init ftrace_mod_cmd_init(void)
1924 return register_ftrace_command(&ftrace_mod_cmd);
1926 device_initcall(ftrace_mod_cmd_init);
1929 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
1931 struct ftrace_func_probe *entry;
1932 struct hlist_head *hhd;
1933 struct hlist_node *n;
1937 key = hash_long(ip, FTRACE_HASH_BITS);
1939 hhd = &ftrace_func_hash[key];
1941 if (hlist_empty(hhd))
1945 * Disable preemption for these calls to prevent a RCU grace
1946 * period. This syncs the hash iteration and freeing of items
1947 * on the hash. rcu_read_lock is too dangerous here.
1949 resched = ftrace_preempt_disable();
1950 hlist_for_each_entry_rcu(entry, n, hhd, node) {
1951 if (entry->ip == ip)
1952 entry->ops->func(ip, parent_ip, &entry->data);
1954 ftrace_preempt_enable(resched);
1957 static struct ftrace_ops trace_probe_ops __read_mostly =
1959 .func = function_trace_probe_call,
1962 static int ftrace_probe_registered;
1964 static void __enable_ftrace_function_probe(void)
1968 if (ftrace_probe_registered)
1971 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1972 struct hlist_head *hhd = &ftrace_func_hash[i];
1976 /* Nothing registered? */
1977 if (i == FTRACE_FUNC_HASHSIZE)
1980 __register_ftrace_function(&trace_probe_ops);
1982 ftrace_probe_registered = 1;
1985 static void __disable_ftrace_function_probe(void)
1989 if (!ftrace_probe_registered)
1992 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1993 struct hlist_head *hhd = &ftrace_func_hash[i];
1998 /* no more funcs left */
1999 __unregister_ftrace_function(&trace_probe_ops);
2001 ftrace_probe_registered = 0;
2005 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
2007 struct ftrace_func_probe *entry =
2008 container_of(rhp, struct ftrace_func_probe, rcu);
2010 if (entry->ops->free)
2011 entry->ops->free(&entry->data);
2017 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2020 struct ftrace_func_probe *entry;
2021 struct ftrace_page *pg;
2022 struct dyn_ftrace *rec;
2028 type = ftrace_setup_glob(glob, strlen(glob), &search, ¬);
2029 len = strlen(search);
2031 /* we do not support '!' for function probes */
2035 mutex_lock(&ftrace_lock);
2036 do_for_each_ftrace_rec(pg, rec) {
2038 if (rec->flags & FTRACE_FL_FAILED)
2041 if (!ftrace_match_record(rec, search, len, type))
2044 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2046 /* If we did not process any, then return error */
2057 * The caller might want to do something special
2058 * for each function we find. We call the callback
2059 * to give the caller an opportunity to do so.
2061 if (ops->callback) {
2062 if (ops->callback(rec->ip, &entry->data) < 0) {
2063 /* caller does not like this func */
2070 entry->ip = rec->ip;
2072 key = hash_long(entry->ip, FTRACE_HASH_BITS);
2073 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
2075 } while_for_each_ftrace_rec();
2076 __enable_ftrace_function_probe();
2079 mutex_unlock(&ftrace_lock);
2085 PROBE_TEST_FUNC = 1,
2090 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2091 void *data, int flags)
2093 struct ftrace_func_probe *entry;
2094 struct hlist_node *n, *tmp;
2095 char str[KSYM_SYMBOL_LEN];
2096 int type = MATCH_FULL;
2100 if (glob && (strcmp(glob, "*") || !strlen(glob)))
2105 type = ftrace_setup_glob(glob, strlen(glob), &search, ¬);
2106 len = strlen(search);
2108 /* we do not support '!' for function probes */
2113 mutex_lock(&ftrace_lock);
2114 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2115 struct hlist_head *hhd = &ftrace_func_hash[i];
2117 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
2119 /* break up if statements for readability */
2120 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
2123 if ((flags & PROBE_TEST_DATA) && entry->data != data)
2126 /* do this last, since it is the most expensive */
2128 kallsyms_lookup(entry->ip, NULL, NULL,
2130 if (!ftrace_match(str, glob, len, type))
2134 hlist_del(&entry->node);
2135 call_rcu(&entry->rcu, ftrace_free_entry_rcu);
2138 __disable_ftrace_function_probe();
2139 mutex_unlock(&ftrace_lock);
2143 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2146 __unregister_ftrace_function_probe(glob, ops, data,
2147 PROBE_TEST_FUNC | PROBE_TEST_DATA);
2151 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
2153 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
2156 void unregister_ftrace_function_probe_all(char *glob)
2158 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
2161 static LIST_HEAD(ftrace_commands);
2162 static DEFINE_MUTEX(ftrace_cmd_mutex);
2164 int register_ftrace_command(struct ftrace_func_command *cmd)
2166 struct ftrace_func_command *p;
2169 mutex_lock(&ftrace_cmd_mutex);
2170 list_for_each_entry(p, &ftrace_commands, list) {
2171 if (strcmp(cmd->name, p->name) == 0) {
2176 list_add(&cmd->list, &ftrace_commands);
2178 mutex_unlock(&ftrace_cmd_mutex);
2183 int unregister_ftrace_command(struct ftrace_func_command *cmd)
2185 struct ftrace_func_command *p, *n;
2188 mutex_lock(&ftrace_cmd_mutex);
2189 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
2190 if (strcmp(cmd->name, p->name) == 0) {
2192 list_del_init(&p->list);
2197 mutex_unlock(&ftrace_cmd_mutex);
2202 static int ftrace_process_regex(char *buff, int len, int enable)
2204 char *func, *command, *next = buff;
2205 struct ftrace_func_command *p;
2208 func = strsep(&next, ":");
2211 ftrace_match_records(func, len, enable);
2217 command = strsep(&next, ":");
2219 mutex_lock(&ftrace_cmd_mutex);
2220 list_for_each_entry(p, &ftrace_commands, list) {
2221 if (strcmp(p->name, command) == 0) {
2222 ret = p->func(func, command, next, enable);
2227 mutex_unlock(&ftrace_cmd_mutex);
2233 ftrace_regex_write(struct file *file, const char __user *ubuf,
2234 size_t cnt, loff_t *ppos, int enable)
2236 struct ftrace_iterator *iter;
2241 if (!cnt || cnt < 0)
2244 mutex_lock(&ftrace_regex_lock);
2246 if (file->f_mode & FMODE_READ) {
2247 struct seq_file *m = file->private_data;
2250 iter = file->private_data;
2253 iter->flags &= ~FTRACE_ITER_CONT;
2254 iter->buffer_idx = 0;
2257 ret = get_user(ch, ubuf++);
2263 if (!(iter->flags & ~FTRACE_ITER_CONT)) {
2264 /* skip white space */
2265 while (cnt && isspace(ch)) {
2266 ret = get_user(ch, ubuf++);
2274 file->f_pos += read;
2279 iter->buffer_idx = 0;
2282 while (cnt && !isspace(ch)) {
2283 if (iter->buffer_idx < FTRACE_BUFF_MAX)
2284 iter->buffer[iter->buffer_idx++] = ch;
2289 ret = get_user(ch, ubuf++);
2298 iter->buffer[iter->buffer_idx] = 0;
2299 ret = ftrace_process_regex(iter->buffer,
2300 iter->buffer_idx, enable);
2303 iter->buffer_idx = 0;
2305 iter->flags |= FTRACE_ITER_CONT;
2308 file->f_pos += read;
2312 mutex_unlock(&ftrace_regex_lock);
2318 ftrace_filter_write(struct file *file, const char __user *ubuf,
2319 size_t cnt, loff_t *ppos)
2321 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
2325 ftrace_notrace_write(struct file *file, const char __user *ubuf,
2326 size_t cnt, loff_t *ppos)
2328 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
2332 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
2334 if (unlikely(ftrace_disabled))
2337 mutex_lock(&ftrace_regex_lock);
2339 ftrace_filter_reset(enable);
2341 ftrace_match_records(buf, len, enable);
2342 mutex_unlock(&ftrace_regex_lock);
2346 * ftrace_set_filter - set a function to filter on in ftrace
2347 * @buf - the string that holds the function filter text.
2348 * @len - the length of the string.
2349 * @reset - non zero to reset all filters before applying this filter.
2351 * Filters denote which functions should be enabled when tracing is enabled.
2352 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2354 void ftrace_set_filter(unsigned char *buf, int len, int reset)
2356 ftrace_set_regex(buf, len, reset, 1);
2360 * ftrace_set_notrace - set a function to not trace in ftrace
2361 * @buf - the string that holds the function notrace text.
2362 * @len - the length of the string.
2363 * @reset - non zero to reset all filters before applying this filter.
2365 * Notrace Filters denote which functions should not be enabled when tracing
2366 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2369 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
2371 ftrace_set_regex(buf, len, reset, 0);
2375 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
2377 struct seq_file *m = (struct seq_file *)file->private_data;
2378 struct ftrace_iterator *iter;
2380 mutex_lock(&ftrace_regex_lock);
2381 if (file->f_mode & FMODE_READ) {
2384 seq_release(inode, file);
2386 iter = file->private_data;
2388 if (iter->buffer_idx) {
2390 iter->buffer[iter->buffer_idx] = 0;
2391 ftrace_match_records(iter->buffer, iter->buffer_idx, enable);
2394 mutex_lock(&ftrace_lock);
2395 if (ftrace_start_up && ftrace_enabled)
2396 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
2397 mutex_unlock(&ftrace_lock);
2400 mutex_unlock(&ftrace_regex_lock);
2405 ftrace_filter_release(struct inode *inode, struct file *file)
2407 return ftrace_regex_release(inode, file, 1);
2411 ftrace_notrace_release(struct inode *inode, struct file *file)
2413 return ftrace_regex_release(inode, file, 0);
2416 static const struct file_operations ftrace_avail_fops = {
2417 .open = ftrace_avail_open,
2419 .llseek = seq_lseek,
2420 .release = ftrace_avail_release,
2423 static const struct file_operations ftrace_failures_fops = {
2424 .open = ftrace_failures_open,
2426 .llseek = seq_lseek,
2427 .release = ftrace_avail_release,
2430 static const struct file_operations ftrace_filter_fops = {
2431 .open = ftrace_filter_open,
2433 .write = ftrace_filter_write,
2434 .llseek = ftrace_regex_lseek,
2435 .release = ftrace_filter_release,
2438 static const struct file_operations ftrace_notrace_fops = {
2439 .open = ftrace_notrace_open,
2441 .write = ftrace_notrace_write,
2442 .llseek = ftrace_regex_lseek,
2443 .release = ftrace_notrace_release,
2446 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2448 static DEFINE_MUTEX(graph_lock);
2450 int ftrace_graph_count;
2451 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
2454 g_next(struct seq_file *m, void *v, loff_t *pos)
2456 unsigned long *array = m->private;
2461 if (index >= ftrace_graph_count)
2464 return &array[index];
2467 static void *g_start(struct seq_file *m, loff_t *pos)
2471 mutex_lock(&graph_lock);
2473 /* Nothing, tell g_show to print all functions are enabled */
2474 if (!ftrace_graph_count && !*pos)
2477 p = g_next(m, p, pos);
2482 static void g_stop(struct seq_file *m, void *p)
2484 mutex_unlock(&graph_lock);
2487 static int g_show(struct seq_file *m, void *v)
2489 unsigned long *ptr = v;
2490 char str[KSYM_SYMBOL_LEN];
2495 if (ptr == (unsigned long *)1) {
2496 seq_printf(m, "#### all functions enabled ####\n");
2500 kallsyms_lookup(*ptr, NULL, NULL, NULL, str);
2502 seq_printf(m, "%s\n", str);
2507 static struct seq_operations ftrace_graph_seq_ops = {
2515 ftrace_graph_open(struct inode *inode, struct file *file)
2519 if (unlikely(ftrace_disabled))
2522 mutex_lock(&graph_lock);
2523 if ((file->f_mode & FMODE_WRITE) &&
2524 !(file->f_flags & O_APPEND)) {
2525 ftrace_graph_count = 0;
2526 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
2529 if (file->f_mode & FMODE_READ) {
2530 ret = seq_open(file, &ftrace_graph_seq_ops);
2532 struct seq_file *m = file->private_data;
2533 m->private = ftrace_graph_funcs;
2536 file->private_data = ftrace_graph_funcs;
2537 mutex_unlock(&graph_lock);
2543 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
2545 struct dyn_ftrace *rec;
2546 struct ftrace_page *pg;
2554 if (ftrace_disabled)
2558 type = ftrace_setup_glob(buffer, strlen(buffer), &search, ¬);
2562 search_len = strlen(search);
2564 mutex_lock(&ftrace_lock);
2565 do_for_each_ftrace_rec(pg, rec) {
2567 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
2570 if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
2573 if (ftrace_match_record(rec, search, search_len, type)) {
2574 /* ensure it is not already in the array */
2576 for (i = 0; i < *idx; i++)
2577 if (array[i] == rec->ip) {
2582 array[(*idx)++] = rec->ip;
2586 } while_for_each_ftrace_rec();
2588 mutex_unlock(&ftrace_lock);
2590 return found ? 0 : -EINVAL;
2594 ftrace_graph_write(struct file *file, const char __user *ubuf,
2595 size_t cnt, loff_t *ppos)
2597 unsigned char buffer[FTRACE_BUFF_MAX+1];
2598 unsigned long *array;
2604 if (!cnt || cnt < 0)
2607 mutex_lock(&graph_lock);
2609 if (ftrace_graph_count >= FTRACE_GRAPH_MAX_FUNCS) {
2614 if (file->f_mode & FMODE_READ) {
2615 struct seq_file *m = file->private_data;
2618 array = file->private_data;
2620 ret = get_user(ch, ubuf++);
2626 /* skip white space */
2627 while (cnt && isspace(ch)) {
2628 ret = get_user(ch, ubuf++);
2641 while (cnt && !isspace(ch)) {
2642 if (index < FTRACE_BUFF_MAX)
2643 buffer[index++] = ch;
2648 ret = get_user(ch, ubuf++);
2656 /* we allow only one expression at a time */
2657 ret = ftrace_set_func(array, &ftrace_graph_count, buffer);
2661 file->f_pos += read;
2665 mutex_unlock(&graph_lock);
2670 static const struct file_operations ftrace_graph_fops = {
2671 .open = ftrace_graph_open,
2673 .write = ftrace_graph_write,
2675 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2677 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
2679 struct dentry *entry;
2681 entry = debugfs_create_file("available_filter_functions", 0444,
2682 d_tracer, NULL, &ftrace_avail_fops);
2684 pr_warning("Could not create debugfs "
2685 "'available_filter_functions' entry\n");
2687 entry = debugfs_create_file("failures", 0444,
2688 d_tracer, NULL, &ftrace_failures_fops);
2690 pr_warning("Could not create debugfs 'failures' entry\n");
2692 entry = debugfs_create_file("set_ftrace_filter", 0644, d_tracer,
2693 NULL, &ftrace_filter_fops);
2695 pr_warning("Could not create debugfs "
2696 "'set_ftrace_filter' entry\n");
2698 entry = debugfs_create_file("set_ftrace_notrace", 0644, d_tracer,
2699 NULL, &ftrace_notrace_fops);
2701 pr_warning("Could not create debugfs "
2702 "'set_ftrace_notrace' entry\n");
2704 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2705 entry = debugfs_create_file("set_graph_function", 0444, d_tracer,
2707 &ftrace_graph_fops);
2709 pr_warning("Could not create debugfs "
2710 "'set_graph_function' entry\n");
2711 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2716 static int ftrace_convert_nops(struct module *mod,
2717 unsigned long *start,
2722 unsigned long flags;
2724 mutex_lock(&ftrace_lock);
2727 addr = ftrace_call_adjust(*p++);
2729 * Some architecture linkers will pad between
2730 * the different mcount_loc sections of different
2731 * object files to satisfy alignments.
2732 * Skip any NULL pointers.
2736 ftrace_record_ip(addr);
2739 /* disable interrupts to prevent kstop machine */
2740 local_irq_save(flags);
2741 ftrace_update_code(mod);
2742 local_irq_restore(flags);
2743 mutex_unlock(&ftrace_lock);
2748 void ftrace_init_module(struct module *mod,
2749 unsigned long *start, unsigned long *end)
2751 if (ftrace_disabled || start == end)
2753 ftrace_convert_nops(mod, start, end);
2756 extern unsigned long __start_mcount_loc[];
2757 extern unsigned long __stop_mcount_loc[];
2759 void __init ftrace_init(void)
2761 unsigned long count, addr, flags;
2764 /* Keep the ftrace pointer to the stub */
2765 addr = (unsigned long)ftrace_stub;
2767 local_irq_save(flags);
2768 ftrace_dyn_arch_init(&addr);
2769 local_irq_restore(flags);
2771 /* ftrace_dyn_arch_init places the return code in addr */
2775 count = __stop_mcount_loc - __start_mcount_loc;
2777 ret = ftrace_dyn_table_alloc(count);
2781 last_ftrace_enabled = ftrace_enabled = 1;
2783 ret = ftrace_convert_nops(NULL,
2789 ftrace_disabled = 1;
2794 static int __init ftrace_nodyn_init(void)
2799 device_initcall(ftrace_nodyn_init);
2801 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
2802 static inline void ftrace_startup_enable(int command) { }
2803 /* Keep as macros so we do not need to define the commands */
2804 # define ftrace_startup(command) do { } while (0)
2805 # define ftrace_shutdown(command) do { } while (0)
2806 # define ftrace_startup_sysctl() do { } while (0)
2807 # define ftrace_shutdown_sysctl() do { } while (0)
2808 #endif /* CONFIG_DYNAMIC_FTRACE */
2811 ftrace_pid_read(struct file *file, char __user *ubuf,
2812 size_t cnt, loff_t *ppos)
2817 if (ftrace_pid_trace == ftrace_swapper_pid)
2818 r = sprintf(buf, "swapper tasks\n");
2819 else if (ftrace_pid_trace)
2820 r = sprintf(buf, "%u\n", pid_vnr(ftrace_pid_trace));
2822 r = sprintf(buf, "no pid\n");
2824 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2827 static void clear_ftrace_swapper(void)
2829 struct task_struct *p;
2833 for_each_online_cpu(cpu) {
2835 clear_tsk_trace_trace(p);
2840 static void set_ftrace_swapper(void)
2842 struct task_struct *p;
2846 for_each_online_cpu(cpu) {
2848 set_tsk_trace_trace(p);
2853 static void clear_ftrace_pid(struct pid *pid)
2855 struct task_struct *p;
2858 do_each_pid_task(pid, PIDTYPE_PID, p) {
2859 clear_tsk_trace_trace(p);
2860 } while_each_pid_task(pid, PIDTYPE_PID, p);
2866 static void set_ftrace_pid(struct pid *pid)
2868 struct task_struct *p;
2871 do_each_pid_task(pid, PIDTYPE_PID, p) {
2872 set_tsk_trace_trace(p);
2873 } while_each_pid_task(pid, PIDTYPE_PID, p);
2877 static void clear_ftrace_pid_task(struct pid **pid)
2879 if (*pid == ftrace_swapper_pid)
2880 clear_ftrace_swapper();
2882 clear_ftrace_pid(*pid);
2887 static void set_ftrace_pid_task(struct pid *pid)
2889 if (pid == ftrace_swapper_pid)
2890 set_ftrace_swapper();
2892 set_ftrace_pid(pid);
2896 ftrace_pid_write(struct file *filp, const char __user *ubuf,
2897 size_t cnt, loff_t *ppos)
2904 if (cnt >= sizeof(buf))
2907 if (copy_from_user(&buf, ubuf, cnt))
2912 ret = strict_strtol(buf, 10, &val);
2916 mutex_lock(&ftrace_lock);
2918 /* disable pid tracing */
2919 if (!ftrace_pid_trace)
2922 clear_ftrace_pid_task(&ftrace_pid_trace);
2925 /* swapper task is special */
2927 pid = ftrace_swapper_pid;
2928 if (pid == ftrace_pid_trace)
2931 pid = find_get_pid(val);
2933 if (pid == ftrace_pid_trace) {
2939 if (ftrace_pid_trace)
2940 clear_ftrace_pid_task(&ftrace_pid_trace);
2945 ftrace_pid_trace = pid;
2947 set_ftrace_pid_task(ftrace_pid_trace);
2950 /* update the function call */
2951 ftrace_update_pid_func();
2952 ftrace_startup_enable(0);
2955 mutex_unlock(&ftrace_lock);
2960 static const struct file_operations ftrace_pid_fops = {
2961 .read = ftrace_pid_read,
2962 .write = ftrace_pid_write,
2965 static __init int ftrace_init_debugfs(void)
2967 struct dentry *d_tracer;
2968 struct dentry *entry;
2970 d_tracer = tracing_init_dentry();
2974 ftrace_init_dyn_debugfs(d_tracer);
2976 entry = debugfs_create_file("set_ftrace_pid", 0644, d_tracer,
2977 NULL, &ftrace_pid_fops);
2979 pr_warning("Could not create debugfs "
2980 "'set_ftrace_pid' entry\n");
2982 ftrace_profile_debugfs(d_tracer);
2986 fs_initcall(ftrace_init_debugfs);
2989 * ftrace_kill - kill ftrace
2991 * This function should be used by panic code. It stops ftrace
2992 * but in a not so nice way. If you need to simply kill ftrace
2993 * from a non-atomic section, use ftrace_kill.
2995 void ftrace_kill(void)
2997 ftrace_disabled = 1;
2999 clear_ftrace_function();
3003 * register_ftrace_function - register a function for profiling
3004 * @ops - ops structure that holds the function for profiling.
3006 * Register a function to be called by all functions in the
3009 * Note: @ops->func and all the functions it calls must be labeled
3010 * with "notrace", otherwise it will go into a
3013 int register_ftrace_function(struct ftrace_ops *ops)
3017 if (unlikely(ftrace_disabled))
3020 mutex_lock(&ftrace_lock);
3022 ret = __register_ftrace_function(ops);
3025 mutex_unlock(&ftrace_lock);
3030 * unregister_ftrace_function - unregister a function for profiling.
3031 * @ops - ops structure that holds the function to unregister
3033 * Unregister a function that was added to be called by ftrace profiling.
3035 int unregister_ftrace_function(struct ftrace_ops *ops)
3039 mutex_lock(&ftrace_lock);
3040 ret = __unregister_ftrace_function(ops);
3042 mutex_unlock(&ftrace_lock);
3048 ftrace_enable_sysctl(struct ctl_table *table, int write,
3049 struct file *file, void __user *buffer, size_t *lenp,
3054 if (unlikely(ftrace_disabled))
3057 mutex_lock(&ftrace_lock);
3059 ret = proc_dointvec(table, write, file, buffer, lenp, ppos);
3061 if (ret || !write || (last_ftrace_enabled == ftrace_enabled))
3064 last_ftrace_enabled = ftrace_enabled;
3066 if (ftrace_enabled) {
3068 ftrace_startup_sysctl();
3070 /* we are starting ftrace again */
3071 if (ftrace_list != &ftrace_list_end) {
3072 if (ftrace_list->next == &ftrace_list_end)
3073 ftrace_trace_function = ftrace_list->func;
3075 ftrace_trace_function = ftrace_list_func;
3079 /* stopping ftrace calls (just send to ftrace_stub) */
3080 ftrace_trace_function = ftrace_stub;
3082 ftrace_shutdown_sysctl();
3086 mutex_unlock(&ftrace_lock);
3090 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3092 static atomic_t ftrace_graph_active;
3093 static struct notifier_block ftrace_suspend_notifier;
3095 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
3100 /* The callbacks that hook a function */
3101 trace_func_graph_ret_t ftrace_graph_return =
3102 (trace_func_graph_ret_t)ftrace_stub;
3103 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
3105 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
3106 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
3110 unsigned long flags;
3111 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
3112 struct task_struct *g, *t;
3114 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
3115 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
3116 * sizeof(struct ftrace_ret_stack),
3118 if (!ret_stack_list[i]) {
3126 read_lock_irqsave(&tasklist_lock, flags);
3127 do_each_thread(g, t) {
3133 if (t->ret_stack == NULL) {
3134 t->curr_ret_stack = -1;
3135 /* Make sure IRQs see the -1 first: */
3137 t->ret_stack = ret_stack_list[start++];
3138 atomic_set(&t->tracing_graph_pause, 0);
3139 atomic_set(&t->trace_overrun, 0);
3141 } while_each_thread(g, t);
3144 read_unlock_irqrestore(&tasklist_lock, flags);
3146 for (i = start; i < end; i++)
3147 kfree(ret_stack_list[i]);
3152 ftrace_graph_probe_sched_switch(struct rq *__rq, struct task_struct *prev,
3153 struct task_struct *next)
3155 unsigned long long timestamp;
3159 * Does the user want to count the time a function was asleep.
3160 * If so, do not update the time stamps.
3162 if (trace_flags & TRACE_ITER_SLEEP_TIME)
3165 timestamp = trace_clock_local();
3167 prev->ftrace_timestamp = timestamp;
3169 /* only process tasks that we timestamped */
3170 if (!next->ftrace_timestamp)
3174 * Update all the counters in next to make up for the
3175 * time next was sleeping.
3177 timestamp -= next->ftrace_timestamp;
3179 for (index = next->curr_ret_stack; index >= 0; index--)
3180 next->ret_stack[index].calltime += timestamp;
3183 /* Allocate a return stack for each task */
3184 static int start_graph_tracing(void)
3186 struct ftrace_ret_stack **ret_stack_list;
3189 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
3190 sizeof(struct ftrace_ret_stack *),
3193 if (!ret_stack_list)
3196 /* The cpu_boot init_task->ret_stack will never be freed */
3197 for_each_online_cpu(cpu)
3198 ftrace_graph_init_task(idle_task(cpu));
3201 ret = alloc_retstack_tasklist(ret_stack_list);
3202 } while (ret == -EAGAIN);
3205 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch);
3207 pr_info("ftrace_graph: Couldn't activate tracepoint"
3208 " probe to kernel_sched_switch\n");
3211 kfree(ret_stack_list);
3216 * Hibernation protection.
3217 * The state of the current task is too much unstable during
3218 * suspend/restore to disk. We want to protect against that.
3221 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
3225 case PM_HIBERNATION_PREPARE:
3226 pause_graph_tracing();
3229 case PM_POST_HIBERNATION:
3230 unpause_graph_tracing();
3236 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
3237 trace_func_graph_ent_t entryfunc)
3241 mutex_lock(&ftrace_lock);
3243 /* we currently allow only one tracer registered at a time */
3244 if (atomic_read(&ftrace_graph_active)) {
3249 ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
3250 register_pm_notifier(&ftrace_suspend_notifier);
3252 atomic_inc(&ftrace_graph_active);
3253 ret = start_graph_tracing();
3255 atomic_dec(&ftrace_graph_active);
3259 ftrace_graph_return = retfunc;
3260 ftrace_graph_entry = entryfunc;
3262 ftrace_startup(FTRACE_START_FUNC_RET);
3265 mutex_unlock(&ftrace_lock);
3269 void unregister_ftrace_graph(void)
3271 mutex_lock(&ftrace_lock);
3273 atomic_dec(&ftrace_graph_active);
3274 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch);
3275 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
3276 ftrace_graph_entry = ftrace_graph_entry_stub;
3277 ftrace_shutdown(FTRACE_STOP_FUNC_RET);
3278 unregister_pm_notifier(&ftrace_suspend_notifier);
3280 mutex_unlock(&ftrace_lock);
3283 /* Allocate a return stack for newly created task */
3284 void ftrace_graph_init_task(struct task_struct *t)
3286 if (atomic_read(&ftrace_graph_active)) {
3287 t->ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
3288 * sizeof(struct ftrace_ret_stack),
3292 t->curr_ret_stack = -1;
3293 atomic_set(&t->tracing_graph_pause, 0);
3294 atomic_set(&t->trace_overrun, 0);
3295 t->ftrace_timestamp = 0;
3297 t->ret_stack = NULL;
3300 void ftrace_graph_exit_task(struct task_struct *t)
3302 struct ftrace_ret_stack *ret_stack = t->ret_stack;
3304 t->ret_stack = NULL;
3305 /* NULL must become visible to IRQs before we free it: */
3311 void ftrace_graph_stop(void)