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/events/sched.h>
34 #include <asm/ftrace.h>
35 #include <asm/setup.h>
37 #include "trace_output.h"
38 #include "trace_stat.h"
40 #define FTRACE_WARN_ON(cond) \
46 #define FTRACE_WARN_ON_ONCE(cond) \
48 if (WARN_ON_ONCE(cond)) \
52 /* hash bits for specific function selection */
53 #define FTRACE_HASH_BITS 7
54 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
56 /* ftrace_enabled is a method to turn ftrace on or off */
57 int ftrace_enabled __read_mostly;
58 static int last_ftrace_enabled;
60 /* Quick disabling of function tracer. */
61 int function_trace_stop;
64 * ftrace_disabled is set when an anomaly is discovered.
65 * ftrace_disabled is much stronger than ftrace_enabled.
67 static int ftrace_disabled __read_mostly;
69 static DEFINE_MUTEX(ftrace_lock);
71 static struct ftrace_ops ftrace_list_end __read_mostly =
76 static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
77 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
78 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
79 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
81 static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
83 struct ftrace_ops *op = ftrace_list;
85 /* in case someone actually ports this to alpha! */
86 read_barrier_depends();
88 while (op != &ftrace_list_end) {
90 read_barrier_depends();
91 op->func(ip, parent_ip);
96 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
98 if (!test_tsk_trace_trace(current))
101 ftrace_pid_function(ip, parent_ip);
104 static void set_ftrace_pid_function(ftrace_func_t func)
106 /* do not set ftrace_pid_function to itself! */
107 if (func != ftrace_pid_func)
108 ftrace_pid_function = func;
112 * clear_ftrace_function - reset the ftrace function
114 * This NULLs the ftrace function and in essence stops
115 * tracing. There may be lag
117 void clear_ftrace_function(void)
119 ftrace_trace_function = ftrace_stub;
120 __ftrace_trace_function = ftrace_stub;
121 ftrace_pid_function = ftrace_stub;
124 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
126 * For those archs that do not test ftrace_trace_stop in their
127 * mcount call site, we need to do it from C.
129 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
131 if (function_trace_stop)
134 __ftrace_trace_function(ip, parent_ip);
138 static int __register_ftrace_function(struct ftrace_ops *ops)
140 ops->next = ftrace_list;
142 * We are entering ops into the ftrace_list but another
143 * CPU might be walking that list. We need to make sure
144 * the ops->next pointer is valid before another CPU sees
145 * the ops pointer included into the ftrace_list.
150 if (ftrace_enabled) {
153 if (ops->next == &ftrace_list_end)
156 func = ftrace_list_func;
158 if (ftrace_pid_trace) {
159 set_ftrace_pid_function(func);
160 func = ftrace_pid_func;
164 * For one func, simply call it directly.
165 * For more than one func, call the chain.
167 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
168 ftrace_trace_function = func;
170 __ftrace_trace_function = func;
171 ftrace_trace_function = ftrace_test_stop_func;
178 static int __unregister_ftrace_function(struct ftrace_ops *ops)
180 struct ftrace_ops **p;
183 * If we are removing the last function, then simply point
184 * to the ftrace_stub.
186 if (ftrace_list == ops && ops->next == &ftrace_list_end) {
187 ftrace_trace_function = ftrace_stub;
188 ftrace_list = &ftrace_list_end;
192 for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
201 if (ftrace_enabled) {
202 /* If we only have one func left, then call that directly */
203 if (ftrace_list->next == &ftrace_list_end) {
204 ftrace_func_t func = ftrace_list->func;
206 if (ftrace_pid_trace) {
207 set_ftrace_pid_function(func);
208 func = ftrace_pid_func;
210 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
211 ftrace_trace_function = func;
213 __ftrace_trace_function = func;
221 static void ftrace_update_pid_func(void)
225 if (ftrace_trace_function == ftrace_stub)
228 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
229 func = ftrace_trace_function;
231 func = __ftrace_trace_function;
234 if (ftrace_pid_trace) {
235 set_ftrace_pid_function(func);
236 func = ftrace_pid_func;
238 if (func == ftrace_pid_func)
239 func = ftrace_pid_function;
242 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
243 ftrace_trace_function = func;
245 __ftrace_trace_function = func;
249 #ifdef CONFIG_FUNCTION_PROFILER
250 struct ftrace_profile {
251 struct hlist_node node;
253 unsigned long counter;
254 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
255 unsigned long long time;
259 struct ftrace_profile_page {
260 struct ftrace_profile_page *next;
262 struct ftrace_profile records[];
265 struct ftrace_profile_stat {
267 struct hlist_head *hash;
268 struct ftrace_profile_page *pages;
269 struct ftrace_profile_page *start;
270 struct tracer_stat stat;
273 #define PROFILE_RECORDS_SIZE \
274 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
276 #define PROFILES_PER_PAGE \
277 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
279 static int ftrace_profile_bits __read_mostly;
280 static int ftrace_profile_enabled __read_mostly;
282 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
283 static DEFINE_MUTEX(ftrace_profile_lock);
285 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
287 #define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
290 function_stat_next(void *v, int idx)
292 struct ftrace_profile *rec = v;
293 struct ftrace_profile_page *pg;
295 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
301 if ((void *)rec >= (void *)&pg->records[pg->index]) {
305 rec = &pg->records[0];
313 static void *function_stat_start(struct tracer_stat *trace)
315 struct ftrace_profile_stat *stat =
316 container_of(trace, struct ftrace_profile_stat, stat);
318 if (!stat || !stat->start)
321 return function_stat_next(&stat->start->records[0], 0);
324 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
325 /* function graph compares on total time */
326 static int function_stat_cmp(void *p1, void *p2)
328 struct ftrace_profile *a = p1;
329 struct ftrace_profile *b = p2;
331 if (a->time < b->time)
333 if (a->time > b->time)
339 /* not function graph compares against hits */
340 static int function_stat_cmp(void *p1, void *p2)
342 struct ftrace_profile *a = p1;
343 struct ftrace_profile *b = p2;
345 if (a->counter < b->counter)
347 if (a->counter > b->counter)
354 static int function_stat_headers(struct seq_file *m)
356 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
357 seq_printf(m, " Function "
362 seq_printf(m, " Function Hit\n"
368 static int function_stat_show(struct seq_file *m, void *v)
370 struct ftrace_profile *rec = v;
371 char str[KSYM_SYMBOL_LEN];
372 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
373 static DEFINE_MUTEX(mutex);
374 static struct trace_seq s;
375 unsigned long long avg;
378 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
379 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
381 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
384 do_div(avg, rec->counter);
388 trace_print_graph_duration(rec->time, &s);
389 trace_seq_puts(&s, " ");
390 trace_print_graph_duration(avg, &s);
391 trace_print_seq(m, &s);
392 mutex_unlock(&mutex);
399 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
401 struct ftrace_profile_page *pg;
403 pg = stat->pages = stat->start;
406 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
411 memset(stat->hash, 0,
412 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
415 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
417 struct ftrace_profile_page *pg;
422 /* If we already allocated, do nothing */
426 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
430 #ifdef CONFIG_DYNAMIC_FTRACE
431 functions = ftrace_update_tot_cnt;
434 * We do not know the number of functions that exist because
435 * dynamic tracing is what counts them. With past experience
436 * we have around 20K functions. That should be more than enough.
437 * It is highly unlikely we will execute every function in
443 pg = stat->start = stat->pages;
445 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
447 for (i = 0; i < pages; i++) {
448 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
459 unsigned long tmp = (unsigned long)pg;
465 free_page((unsigned long)stat->pages);
472 static int ftrace_profile_init_cpu(int cpu)
474 struct ftrace_profile_stat *stat;
477 stat = &per_cpu(ftrace_profile_stats, cpu);
480 /* If the profile is already created, simply reset it */
481 ftrace_profile_reset(stat);
486 * We are profiling all functions, but usually only a few thousand
487 * functions are hit. We'll make a hash of 1024 items.
489 size = FTRACE_PROFILE_HASH_SIZE;
491 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
496 if (!ftrace_profile_bits) {
499 for (; size; size >>= 1)
500 ftrace_profile_bits++;
503 /* Preallocate the function profiling pages */
504 if (ftrace_profile_pages_init(stat) < 0) {
513 static int ftrace_profile_init(void)
518 for_each_online_cpu(cpu) {
519 ret = ftrace_profile_init_cpu(cpu);
527 /* interrupts must be disabled */
528 static struct ftrace_profile *
529 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
531 struct ftrace_profile *rec;
532 struct hlist_head *hhd;
533 struct hlist_node *n;
536 key = hash_long(ip, ftrace_profile_bits);
537 hhd = &stat->hash[key];
539 if (hlist_empty(hhd))
542 hlist_for_each_entry_rcu(rec, n, hhd, node) {
550 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
551 struct ftrace_profile *rec)
555 key = hash_long(rec->ip, ftrace_profile_bits);
556 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
560 * The memory is already allocated, this simply finds a new record to use.
562 static struct ftrace_profile *
563 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
565 struct ftrace_profile *rec = NULL;
567 /* prevent recursion (from NMIs) */
568 if (atomic_inc_return(&stat->disabled) != 1)
572 * Try to find the function again since an NMI
573 * could have added it
575 rec = ftrace_find_profiled_func(stat, ip);
579 if (stat->pages->index == PROFILES_PER_PAGE) {
580 if (!stat->pages->next)
582 stat->pages = stat->pages->next;
585 rec = &stat->pages->records[stat->pages->index++];
587 ftrace_add_profile(stat, rec);
590 atomic_dec(&stat->disabled);
596 function_profile_call(unsigned long ip, unsigned long parent_ip)
598 struct ftrace_profile_stat *stat;
599 struct ftrace_profile *rec;
602 if (!ftrace_profile_enabled)
605 local_irq_save(flags);
607 stat = &__get_cpu_var(ftrace_profile_stats);
608 if (!stat->hash || !ftrace_profile_enabled)
611 rec = ftrace_find_profiled_func(stat, ip);
613 rec = ftrace_profile_alloc(stat, ip);
620 local_irq_restore(flags);
623 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
624 static int profile_graph_entry(struct ftrace_graph_ent *trace)
626 function_profile_call(trace->func, 0);
630 static void profile_graph_return(struct ftrace_graph_ret *trace)
632 struct ftrace_profile_stat *stat;
633 unsigned long long calltime;
634 struct ftrace_profile *rec;
637 local_irq_save(flags);
638 stat = &__get_cpu_var(ftrace_profile_stats);
639 if (!stat->hash || !ftrace_profile_enabled)
642 calltime = trace->rettime - trace->calltime;
644 if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
647 index = trace->depth;
649 /* Append this call time to the parent time to subtract */
651 current->ret_stack[index - 1].subtime += calltime;
653 if (current->ret_stack[index].subtime < calltime)
654 calltime -= current->ret_stack[index].subtime;
659 rec = ftrace_find_profiled_func(stat, trace->func);
661 rec->time += calltime;
664 local_irq_restore(flags);
667 static int register_ftrace_profiler(void)
669 return register_ftrace_graph(&profile_graph_return,
670 &profile_graph_entry);
673 static void unregister_ftrace_profiler(void)
675 unregister_ftrace_graph();
678 static struct ftrace_ops ftrace_profile_ops __read_mostly =
680 .func = function_profile_call,
683 static int register_ftrace_profiler(void)
685 return register_ftrace_function(&ftrace_profile_ops);
688 static void unregister_ftrace_profiler(void)
690 unregister_ftrace_function(&ftrace_profile_ops);
692 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
695 ftrace_profile_write(struct file *filp, const char __user *ubuf,
696 size_t cnt, loff_t *ppos)
699 char buf[64]; /* big enough to hold a number */
702 if (cnt >= sizeof(buf))
705 if (copy_from_user(&buf, ubuf, cnt))
710 ret = strict_strtoul(buf, 10, &val);
716 mutex_lock(&ftrace_profile_lock);
717 if (ftrace_profile_enabled ^ val) {
719 ret = ftrace_profile_init();
725 ret = register_ftrace_profiler();
730 ftrace_profile_enabled = 1;
732 ftrace_profile_enabled = 0;
734 * unregister_ftrace_profiler calls stop_machine
735 * so this acts like an synchronize_sched.
737 unregister_ftrace_profiler();
741 mutex_unlock(&ftrace_profile_lock);
749 ftrace_profile_read(struct file *filp, char __user *ubuf,
750 size_t cnt, loff_t *ppos)
752 char buf[64]; /* big enough to hold a number */
755 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
756 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
759 static const struct file_operations ftrace_profile_fops = {
760 .open = tracing_open_generic,
761 .read = ftrace_profile_read,
762 .write = ftrace_profile_write,
765 /* used to initialize the real stat files */
766 static struct tracer_stat function_stats __initdata = {
768 .stat_start = function_stat_start,
769 .stat_next = function_stat_next,
770 .stat_cmp = function_stat_cmp,
771 .stat_headers = function_stat_headers,
772 .stat_show = function_stat_show
775 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
777 struct ftrace_profile_stat *stat;
778 struct dentry *entry;
783 for_each_possible_cpu(cpu) {
784 stat = &per_cpu(ftrace_profile_stats, cpu);
786 /* allocate enough for function name + cpu number */
787 name = kmalloc(32, GFP_KERNEL);
790 * The files created are permanent, if something happens
791 * we still do not free memory.
794 "Could not allocate stat file for cpu %d\n",
798 stat->stat = function_stats;
799 snprintf(name, 32, "function%d", cpu);
800 stat->stat.name = name;
801 ret = register_stat_tracer(&stat->stat);
804 "Could not register function stat for cpu %d\n",
811 entry = debugfs_create_file("function_profile_enabled", 0644,
812 d_tracer, NULL, &ftrace_profile_fops);
814 pr_warning("Could not create debugfs "
815 "'function_profile_enabled' entry\n");
818 #else /* CONFIG_FUNCTION_PROFILER */
819 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
822 #endif /* CONFIG_FUNCTION_PROFILER */
824 /* set when tracing only a pid */
825 struct pid *ftrace_pid_trace;
826 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
828 #ifdef CONFIG_DYNAMIC_FTRACE
830 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
831 # error Dynamic ftrace depends on MCOUNT_RECORD
834 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
836 struct ftrace_func_probe {
837 struct hlist_node node;
838 struct ftrace_probe_ops *ops;
846 FTRACE_ENABLE_CALLS = (1 << 0),
847 FTRACE_DISABLE_CALLS = (1 << 1),
848 FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
849 FTRACE_ENABLE_MCOUNT = (1 << 3),
850 FTRACE_DISABLE_MCOUNT = (1 << 4),
851 FTRACE_START_FUNC_RET = (1 << 5),
852 FTRACE_STOP_FUNC_RET = (1 << 6),
855 static int ftrace_filtered;
857 static struct dyn_ftrace *ftrace_new_addrs;
859 static DEFINE_MUTEX(ftrace_regex_lock);
862 struct ftrace_page *next;
864 struct dyn_ftrace records[];
867 #define ENTRIES_PER_PAGE \
868 ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
870 /* estimate from running different kernels */
871 #define NR_TO_INIT 10000
873 static struct ftrace_page *ftrace_pages_start;
874 static struct ftrace_page *ftrace_pages;
876 static struct dyn_ftrace *ftrace_free_records;
879 * This is a double for. Do not use 'break' to break out of the loop,
880 * you must use a goto.
882 #define do_for_each_ftrace_rec(pg, rec) \
883 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
885 for (_____i = 0; _____i < pg->index; _____i++) { \
886 rec = &pg->records[_____i];
888 #define while_for_each_ftrace_rec() \
892 #ifdef CONFIG_KPROBES
894 static int frozen_record_count;
896 static inline void freeze_record(struct dyn_ftrace *rec)
898 if (!(rec->flags & FTRACE_FL_FROZEN)) {
899 rec->flags |= FTRACE_FL_FROZEN;
900 frozen_record_count++;
904 static inline void unfreeze_record(struct dyn_ftrace *rec)
906 if (rec->flags & FTRACE_FL_FROZEN) {
907 rec->flags &= ~FTRACE_FL_FROZEN;
908 frozen_record_count--;
912 static inline int record_frozen(struct dyn_ftrace *rec)
914 return rec->flags & FTRACE_FL_FROZEN;
917 # define freeze_record(rec) ({ 0; })
918 # define unfreeze_record(rec) ({ 0; })
919 # define record_frozen(rec) ({ 0; })
920 #endif /* CONFIG_KPROBES */
922 static void ftrace_free_rec(struct dyn_ftrace *rec)
924 rec->freelist = ftrace_free_records;
925 ftrace_free_records = rec;
926 rec->flags |= FTRACE_FL_FREE;
929 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
931 struct dyn_ftrace *rec;
933 /* First check for freed records */
934 if (ftrace_free_records) {
935 rec = ftrace_free_records;
937 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
938 FTRACE_WARN_ON_ONCE(1);
939 ftrace_free_records = NULL;
943 ftrace_free_records = rec->freelist;
944 memset(rec, 0, sizeof(*rec));
948 if (ftrace_pages->index == ENTRIES_PER_PAGE) {
949 if (!ftrace_pages->next) {
950 /* allocate another page */
952 (void *)get_zeroed_page(GFP_KERNEL);
953 if (!ftrace_pages->next)
956 ftrace_pages = ftrace_pages->next;
959 return &ftrace_pages->records[ftrace_pages->index++];
962 static struct dyn_ftrace *
963 ftrace_record_ip(unsigned long ip)
965 struct dyn_ftrace *rec;
970 rec = ftrace_alloc_dyn_node(ip);
975 rec->newlist = ftrace_new_addrs;
976 ftrace_new_addrs = rec;
981 static void print_ip_ins(const char *fmt, unsigned char *p)
985 printk(KERN_CONT "%s", fmt);
987 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
988 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
991 static void ftrace_bug(int failed, unsigned long ip)
995 FTRACE_WARN_ON_ONCE(1);
996 pr_info("ftrace faulted on modifying ");
1000 FTRACE_WARN_ON_ONCE(1);
1001 pr_info("ftrace failed to modify ");
1003 print_ip_ins(" actual: ", (unsigned char *)ip);
1004 printk(KERN_CONT "\n");
1007 FTRACE_WARN_ON_ONCE(1);
1008 pr_info("ftrace faulted on writing ");
1012 FTRACE_WARN_ON_ONCE(1);
1013 pr_info("ftrace faulted on unknown error ");
1020 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1022 unsigned long ftrace_addr;
1023 unsigned long flag = 0UL;
1025 ftrace_addr = (unsigned long)FTRACE_ADDR;
1028 * If this record is not to be traced or we want to disable it,
1031 * If we want to enable it and filtering is off, then enable it.
1033 * If we want to enable it and filtering is on, enable it only if
1036 if (enable && !(rec->flags & FTRACE_FL_NOTRACE)) {
1037 if (!ftrace_filtered || (rec->flags & FTRACE_FL_FILTER))
1038 flag = FTRACE_FL_ENABLED;
1041 /* If the state of this record hasn't changed, then do nothing */
1042 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1046 rec->flags |= FTRACE_FL_ENABLED;
1047 return ftrace_make_call(rec, ftrace_addr);
1050 rec->flags &= ~FTRACE_FL_ENABLED;
1051 return ftrace_make_nop(NULL, rec, ftrace_addr);
1054 static void ftrace_replace_code(int enable)
1056 struct dyn_ftrace *rec;
1057 struct ftrace_page *pg;
1060 do_for_each_ftrace_rec(pg, rec) {
1062 * Skip over free records, records that have
1063 * failed and not converted.
1065 if (rec->flags & FTRACE_FL_FREE ||
1066 rec->flags & FTRACE_FL_FAILED ||
1067 !(rec->flags & FTRACE_FL_CONVERTED))
1070 /* ignore updates to this record's mcount site */
1071 if (get_kprobe((void *)rec->ip)) {
1075 unfreeze_record(rec);
1078 failed = __ftrace_replace_code(rec, enable);
1080 rec->flags |= FTRACE_FL_FAILED;
1081 ftrace_bug(failed, rec->ip);
1082 /* Stop processing */
1085 } while_for_each_ftrace_rec();
1089 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1096 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1098 ftrace_bug(ret, ip);
1099 rec->flags |= FTRACE_FL_FAILED;
1106 * archs can override this function if they must do something
1107 * before the modifying code is performed.
1109 int __weak ftrace_arch_code_modify_prepare(void)
1115 * archs can override this function if they must do something
1116 * after the modifying code is performed.
1118 int __weak ftrace_arch_code_modify_post_process(void)
1123 static int __ftrace_modify_code(void *data)
1125 int *command = data;
1127 if (*command & FTRACE_ENABLE_CALLS)
1128 ftrace_replace_code(1);
1129 else if (*command & FTRACE_DISABLE_CALLS)
1130 ftrace_replace_code(0);
1132 if (*command & FTRACE_UPDATE_TRACE_FUNC)
1133 ftrace_update_ftrace_func(ftrace_trace_function);
1135 if (*command & FTRACE_START_FUNC_RET)
1136 ftrace_enable_ftrace_graph_caller();
1137 else if (*command & FTRACE_STOP_FUNC_RET)
1138 ftrace_disable_ftrace_graph_caller();
1143 static void ftrace_run_update_code(int command)
1147 ret = ftrace_arch_code_modify_prepare();
1148 FTRACE_WARN_ON(ret);
1152 stop_machine(__ftrace_modify_code, &command, NULL);
1154 ret = ftrace_arch_code_modify_post_process();
1155 FTRACE_WARN_ON(ret);
1158 static ftrace_func_t saved_ftrace_func;
1159 static int ftrace_start_up;
1161 static void ftrace_startup_enable(int command)
1163 if (saved_ftrace_func != ftrace_trace_function) {
1164 saved_ftrace_func = ftrace_trace_function;
1165 command |= FTRACE_UPDATE_TRACE_FUNC;
1168 if (!command || !ftrace_enabled)
1171 ftrace_run_update_code(command);
1174 static void ftrace_startup(int command)
1176 if (unlikely(ftrace_disabled))
1180 command |= FTRACE_ENABLE_CALLS;
1182 ftrace_startup_enable(command);
1185 static void ftrace_shutdown(int command)
1187 if (unlikely(ftrace_disabled))
1192 * Just warn in case of unbalance, no need to kill ftrace, it's not
1193 * critical but the ftrace_call callers may be never nopped again after
1194 * further ftrace uses.
1196 WARN_ON_ONCE(ftrace_start_up < 0);
1198 if (!ftrace_start_up)
1199 command |= FTRACE_DISABLE_CALLS;
1201 if (saved_ftrace_func != ftrace_trace_function) {
1202 saved_ftrace_func = ftrace_trace_function;
1203 command |= FTRACE_UPDATE_TRACE_FUNC;
1206 if (!command || !ftrace_enabled)
1209 ftrace_run_update_code(command);
1212 static void ftrace_startup_sysctl(void)
1214 int command = FTRACE_ENABLE_MCOUNT;
1216 if (unlikely(ftrace_disabled))
1219 /* Force update next time */
1220 saved_ftrace_func = NULL;
1221 /* ftrace_start_up is true if we want ftrace running */
1222 if (ftrace_start_up)
1223 command |= FTRACE_ENABLE_CALLS;
1225 ftrace_run_update_code(command);
1228 static void ftrace_shutdown_sysctl(void)
1230 int command = FTRACE_DISABLE_MCOUNT;
1232 if (unlikely(ftrace_disabled))
1235 /* ftrace_start_up is true if ftrace is running */
1236 if (ftrace_start_up)
1237 command |= FTRACE_DISABLE_CALLS;
1239 ftrace_run_update_code(command);
1242 static cycle_t ftrace_update_time;
1243 static unsigned long ftrace_update_cnt;
1244 unsigned long ftrace_update_tot_cnt;
1246 static int ftrace_update_code(struct module *mod)
1248 struct dyn_ftrace *p;
1249 cycle_t start, stop;
1251 start = ftrace_now(raw_smp_processor_id());
1252 ftrace_update_cnt = 0;
1254 while (ftrace_new_addrs) {
1256 /* If something went wrong, bail without enabling anything */
1257 if (unlikely(ftrace_disabled))
1260 p = ftrace_new_addrs;
1261 ftrace_new_addrs = p->newlist;
1264 /* convert record (i.e, patch mcount-call with NOP) */
1265 if (ftrace_code_disable(mod, p)) {
1266 p->flags |= FTRACE_FL_CONVERTED;
1267 ftrace_update_cnt++;
1272 stop = ftrace_now(raw_smp_processor_id());
1273 ftrace_update_time = stop - start;
1274 ftrace_update_tot_cnt += ftrace_update_cnt;
1279 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
1281 struct ftrace_page *pg;
1285 /* allocate a few pages */
1286 ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
1287 if (!ftrace_pages_start)
1291 * Allocate a few more pages.
1293 * TODO: have some parser search vmlinux before
1294 * final linking to find all calls to ftrace.
1296 * a) know how many pages to allocate.
1298 * b) set up the table then.
1300 * The dynamic code is still necessary for
1304 pg = ftrace_pages = ftrace_pages_start;
1306 cnt = num_to_init / ENTRIES_PER_PAGE;
1307 pr_info("ftrace: allocating %ld entries in %d pages\n",
1308 num_to_init, cnt + 1);
1310 for (i = 0; i < cnt; i++) {
1311 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
1313 /* If we fail, we'll try later anyway */
1324 FTRACE_ITER_FILTER = (1 << 0),
1325 FTRACE_ITER_NOTRACE = (1 << 1),
1326 FTRACE_ITER_FAILURES = (1 << 2),
1327 FTRACE_ITER_PRINTALL = (1 << 3),
1328 FTRACE_ITER_HASH = (1 << 4),
1331 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
1333 struct ftrace_iterator {
1334 struct ftrace_page *pg;
1338 struct trace_parser parser;
1342 t_hash_next(struct seq_file *m, void *v, loff_t *pos)
1344 struct ftrace_iterator *iter = m->private;
1345 struct hlist_node *hnd = v;
1346 struct hlist_head *hhd;
1348 WARN_ON(!(iter->flags & FTRACE_ITER_HASH));
1353 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
1356 hhd = &ftrace_func_hash[iter->hidx];
1358 if (hlist_empty(hhd)) {
1377 static void *t_hash_start(struct seq_file *m, loff_t *pos)
1379 struct ftrace_iterator *iter = m->private;
1383 if (!(iter->flags & FTRACE_ITER_HASH))
1386 iter->flags |= FTRACE_ITER_HASH;
1389 for (l = 0; l <= *pos; ) {
1390 p = t_hash_next(m, p, &l);
1397 static int t_hash_show(struct seq_file *m, void *v)
1399 struct ftrace_func_probe *rec;
1400 struct hlist_node *hnd = v;
1402 rec = hlist_entry(hnd, struct ftrace_func_probe, node);
1404 if (rec->ops->print)
1405 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
1407 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
1410 seq_printf(m, ":%p", rec->data);
1417 t_next(struct seq_file *m, void *v, loff_t *pos)
1419 struct ftrace_iterator *iter = m->private;
1420 struct dyn_ftrace *rec = NULL;
1422 if (iter->flags & FTRACE_ITER_HASH)
1423 return t_hash_next(m, v, pos);
1427 if (iter->flags & FTRACE_ITER_PRINTALL)
1431 if (iter->idx >= iter->pg->index) {
1432 if (iter->pg->next) {
1433 iter->pg = iter->pg->next;
1438 rec = &iter->pg->records[iter->idx++];
1439 if ((rec->flags & FTRACE_FL_FREE) ||
1441 (!(iter->flags & FTRACE_ITER_FAILURES) &&
1442 (rec->flags & FTRACE_FL_FAILED)) ||
1444 ((iter->flags & FTRACE_ITER_FAILURES) &&
1445 !(rec->flags & FTRACE_FL_FAILED)) ||
1447 ((iter->flags & FTRACE_ITER_FILTER) &&
1448 !(rec->flags & FTRACE_FL_FILTER)) ||
1450 ((iter->flags & FTRACE_ITER_NOTRACE) &&
1451 !(rec->flags & FTRACE_FL_NOTRACE))) {
1460 static void *t_start(struct seq_file *m, loff_t *pos)
1462 struct ftrace_iterator *iter = m->private;
1466 mutex_lock(&ftrace_lock);
1468 * For set_ftrace_filter reading, if we have the filter
1469 * off, we can short cut and just print out that all
1470 * functions are enabled.
1472 if (iter->flags & FTRACE_ITER_FILTER && !ftrace_filtered) {
1474 return t_hash_start(m, pos);
1475 iter->flags |= FTRACE_ITER_PRINTALL;
1479 if (iter->flags & FTRACE_ITER_HASH)
1480 return t_hash_start(m, pos);
1482 iter->pg = ftrace_pages_start;
1484 for (l = 0; l <= *pos; ) {
1485 p = t_next(m, p, &l);
1490 if (!p && iter->flags & FTRACE_ITER_FILTER)
1491 return t_hash_start(m, pos);
1496 static void t_stop(struct seq_file *m, void *p)
1498 mutex_unlock(&ftrace_lock);
1501 static int t_show(struct seq_file *m, void *v)
1503 struct ftrace_iterator *iter = m->private;
1504 struct dyn_ftrace *rec = v;
1506 if (iter->flags & FTRACE_ITER_HASH)
1507 return t_hash_show(m, v);
1509 if (iter->flags & FTRACE_ITER_PRINTALL) {
1510 seq_printf(m, "#### all functions enabled ####\n");
1517 seq_printf(m, "%ps\n", (void *)rec->ip);
1522 static const struct seq_operations show_ftrace_seq_ops = {
1530 ftrace_avail_open(struct inode *inode, struct file *file)
1532 struct ftrace_iterator *iter;
1535 if (unlikely(ftrace_disabled))
1538 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1542 iter->pg = ftrace_pages_start;
1544 ret = seq_open(file, &show_ftrace_seq_ops);
1546 struct seq_file *m = file->private_data;
1557 ftrace_failures_open(struct inode *inode, struct file *file)
1561 struct ftrace_iterator *iter;
1563 ret = ftrace_avail_open(inode, file);
1565 m = (struct seq_file *)file->private_data;
1566 iter = (struct ftrace_iterator *)m->private;
1567 iter->flags = FTRACE_ITER_FAILURES;
1574 static void ftrace_filter_reset(int enable)
1576 struct ftrace_page *pg;
1577 struct dyn_ftrace *rec;
1578 unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1580 mutex_lock(&ftrace_lock);
1582 ftrace_filtered = 0;
1583 do_for_each_ftrace_rec(pg, rec) {
1584 if (rec->flags & FTRACE_FL_FAILED)
1586 rec->flags &= ~type;
1587 } while_for_each_ftrace_rec();
1588 mutex_unlock(&ftrace_lock);
1592 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
1594 struct ftrace_iterator *iter;
1597 if (unlikely(ftrace_disabled))
1600 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1604 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
1609 mutex_lock(&ftrace_regex_lock);
1610 if ((file->f_mode & FMODE_WRITE) &&
1611 (file->f_flags & O_TRUNC))
1612 ftrace_filter_reset(enable);
1614 if (file->f_mode & FMODE_READ) {
1615 iter->pg = ftrace_pages_start;
1616 iter->flags = enable ? FTRACE_ITER_FILTER :
1617 FTRACE_ITER_NOTRACE;
1619 ret = seq_open(file, &show_ftrace_seq_ops);
1621 struct seq_file *m = file->private_data;
1624 trace_parser_put(&iter->parser);
1628 file->private_data = iter;
1629 mutex_unlock(&ftrace_regex_lock);
1635 ftrace_filter_open(struct inode *inode, struct file *file)
1637 return ftrace_regex_open(inode, file, 1);
1641 ftrace_notrace_open(struct inode *inode, struct file *file)
1643 return ftrace_regex_open(inode, file, 0);
1647 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1651 if (file->f_mode & FMODE_READ)
1652 ret = seq_lseek(file, offset, origin);
1654 file->f_pos = ret = 1;
1667 * (static function - no need for kernel doc)
1669 * Pass in a buffer containing a glob and this function will
1670 * set search to point to the search part of the buffer and
1671 * return the type of search it is (see enum above).
1672 * This does modify buff.
1674 * Returns enum type.
1675 * search returns the pointer to use for comparison.
1676 * not returns 1 if buff started with a '!'
1680 ftrace_setup_glob(char *buff, int len, char **search, int *not)
1682 int type = MATCH_FULL;
1685 if (buff[0] == '!') {
1694 for (i = 0; i < len; i++) {
1695 if (buff[i] == '*') {
1698 type = MATCH_END_ONLY;
1700 if (type == MATCH_END_ONLY)
1701 type = MATCH_MIDDLE_ONLY;
1703 type = MATCH_FRONT_ONLY;
1713 static int ftrace_match(char *str, char *regex, int len, int type)
1720 if (strcmp(str, regex) == 0)
1723 case MATCH_FRONT_ONLY:
1724 if (strncmp(str, regex, len) == 0)
1727 case MATCH_MIDDLE_ONLY:
1728 if (strstr(str, regex))
1731 case MATCH_END_ONLY:
1732 ptr = strstr(str, regex);
1733 if (ptr && (ptr[len] == 0))
1742 ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
1744 char str[KSYM_SYMBOL_LEN];
1746 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1747 return ftrace_match(str, regex, len, type);
1750 static void ftrace_match_records(char *buff, int len, int enable)
1752 unsigned int search_len;
1753 struct ftrace_page *pg;
1754 struct dyn_ftrace *rec;
1760 flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1761 type = ftrace_setup_glob(buff, len, &search, ¬);
1763 search_len = strlen(search);
1765 mutex_lock(&ftrace_lock);
1766 do_for_each_ftrace_rec(pg, rec) {
1768 if (rec->flags & FTRACE_FL_FAILED)
1771 if (ftrace_match_record(rec, search, search_len, type)) {
1773 rec->flags &= ~flag;
1778 * Only enable filtering if we have a function that
1781 if (enable && (rec->flags & FTRACE_FL_FILTER))
1782 ftrace_filtered = 1;
1783 } while_for_each_ftrace_rec();
1784 mutex_unlock(&ftrace_lock);
1788 ftrace_match_module_record(struct dyn_ftrace *rec, char *mod,
1789 char *regex, int len, int type)
1791 char str[KSYM_SYMBOL_LEN];
1794 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
1796 if (!modname || strcmp(modname, mod))
1799 /* blank search means to match all funcs in the mod */
1801 return ftrace_match(str, regex, len, type);
1806 static void ftrace_match_module_records(char *buff, char *mod, int enable)
1808 unsigned search_len = 0;
1809 struct ftrace_page *pg;
1810 struct dyn_ftrace *rec;
1811 int type = MATCH_FULL;
1812 char *search = buff;
1816 flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1818 /* blank or '*' mean the same */
1819 if (strcmp(buff, "*") == 0)
1822 /* handle the case of 'dont filter this module' */
1823 if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
1829 type = ftrace_setup_glob(buff, strlen(buff), &search, ¬);
1830 search_len = strlen(search);
1833 mutex_lock(&ftrace_lock);
1834 do_for_each_ftrace_rec(pg, rec) {
1836 if (rec->flags & FTRACE_FL_FAILED)
1839 if (ftrace_match_module_record(rec, mod,
1840 search, search_len, type)) {
1842 rec->flags &= ~flag;
1846 if (enable && (rec->flags & FTRACE_FL_FILTER))
1847 ftrace_filtered = 1;
1849 } while_for_each_ftrace_rec();
1850 mutex_unlock(&ftrace_lock);
1854 * We register the module command as a template to show others how
1855 * to register the a command as well.
1859 ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
1864 * cmd == 'mod' because we only registered this func
1865 * for the 'mod' ftrace_func_command.
1866 * But if you register one func with multiple commands,
1867 * you can tell which command was used by the cmd
1871 /* we must have a module name */
1875 mod = strsep(¶m, ":");
1879 ftrace_match_module_records(func, mod, enable);
1883 static struct ftrace_func_command ftrace_mod_cmd = {
1885 .func = ftrace_mod_callback,
1888 static int __init ftrace_mod_cmd_init(void)
1890 return register_ftrace_command(&ftrace_mod_cmd);
1892 device_initcall(ftrace_mod_cmd_init);
1895 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
1897 struct ftrace_func_probe *entry;
1898 struct hlist_head *hhd;
1899 struct hlist_node *n;
1903 key = hash_long(ip, FTRACE_HASH_BITS);
1905 hhd = &ftrace_func_hash[key];
1907 if (hlist_empty(hhd))
1911 * Disable preemption for these calls to prevent a RCU grace
1912 * period. This syncs the hash iteration and freeing of items
1913 * on the hash. rcu_read_lock is too dangerous here.
1915 resched = ftrace_preempt_disable();
1916 hlist_for_each_entry_rcu(entry, n, hhd, node) {
1917 if (entry->ip == ip)
1918 entry->ops->func(ip, parent_ip, &entry->data);
1920 ftrace_preempt_enable(resched);
1923 static struct ftrace_ops trace_probe_ops __read_mostly =
1925 .func = function_trace_probe_call,
1928 static int ftrace_probe_registered;
1930 static void __enable_ftrace_function_probe(void)
1934 if (ftrace_probe_registered)
1937 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1938 struct hlist_head *hhd = &ftrace_func_hash[i];
1942 /* Nothing registered? */
1943 if (i == FTRACE_FUNC_HASHSIZE)
1946 __register_ftrace_function(&trace_probe_ops);
1948 ftrace_probe_registered = 1;
1951 static void __disable_ftrace_function_probe(void)
1955 if (!ftrace_probe_registered)
1958 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1959 struct hlist_head *hhd = &ftrace_func_hash[i];
1964 /* no more funcs left */
1965 __unregister_ftrace_function(&trace_probe_ops);
1967 ftrace_probe_registered = 0;
1971 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
1973 struct ftrace_func_probe *entry =
1974 container_of(rhp, struct ftrace_func_probe, rcu);
1976 if (entry->ops->free)
1977 entry->ops->free(&entry->data);
1983 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
1986 struct ftrace_func_probe *entry;
1987 struct ftrace_page *pg;
1988 struct dyn_ftrace *rec;
1994 type = ftrace_setup_glob(glob, strlen(glob), &search, ¬);
1995 len = strlen(search);
1997 /* we do not support '!' for function probes */
2001 mutex_lock(&ftrace_lock);
2002 do_for_each_ftrace_rec(pg, rec) {
2004 if (rec->flags & FTRACE_FL_FAILED)
2007 if (!ftrace_match_record(rec, search, len, type))
2010 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2012 /* If we did not process any, then return error */
2023 * The caller might want to do something special
2024 * for each function we find. We call the callback
2025 * to give the caller an opportunity to do so.
2027 if (ops->callback) {
2028 if (ops->callback(rec->ip, &entry->data) < 0) {
2029 /* caller does not like this func */
2036 entry->ip = rec->ip;
2038 key = hash_long(entry->ip, FTRACE_HASH_BITS);
2039 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
2041 } while_for_each_ftrace_rec();
2042 __enable_ftrace_function_probe();
2045 mutex_unlock(&ftrace_lock);
2051 PROBE_TEST_FUNC = 1,
2056 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2057 void *data, int flags)
2059 struct ftrace_func_probe *entry;
2060 struct hlist_node *n, *tmp;
2061 char str[KSYM_SYMBOL_LEN];
2062 int type = MATCH_FULL;
2066 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
2071 type = ftrace_setup_glob(glob, strlen(glob), &search, ¬);
2072 len = strlen(search);
2074 /* we do not support '!' for function probes */
2079 mutex_lock(&ftrace_lock);
2080 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2081 struct hlist_head *hhd = &ftrace_func_hash[i];
2083 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
2085 /* break up if statements for readability */
2086 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
2089 if ((flags & PROBE_TEST_DATA) && entry->data != data)
2092 /* do this last, since it is the most expensive */
2094 kallsyms_lookup(entry->ip, NULL, NULL,
2096 if (!ftrace_match(str, glob, len, type))
2100 hlist_del(&entry->node);
2101 call_rcu(&entry->rcu, ftrace_free_entry_rcu);
2104 __disable_ftrace_function_probe();
2105 mutex_unlock(&ftrace_lock);
2109 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2112 __unregister_ftrace_function_probe(glob, ops, data,
2113 PROBE_TEST_FUNC | PROBE_TEST_DATA);
2117 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
2119 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
2122 void unregister_ftrace_function_probe_all(char *glob)
2124 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
2127 static LIST_HEAD(ftrace_commands);
2128 static DEFINE_MUTEX(ftrace_cmd_mutex);
2130 int register_ftrace_command(struct ftrace_func_command *cmd)
2132 struct ftrace_func_command *p;
2135 mutex_lock(&ftrace_cmd_mutex);
2136 list_for_each_entry(p, &ftrace_commands, list) {
2137 if (strcmp(cmd->name, p->name) == 0) {
2142 list_add(&cmd->list, &ftrace_commands);
2144 mutex_unlock(&ftrace_cmd_mutex);
2149 int unregister_ftrace_command(struct ftrace_func_command *cmd)
2151 struct ftrace_func_command *p, *n;
2154 mutex_lock(&ftrace_cmd_mutex);
2155 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
2156 if (strcmp(cmd->name, p->name) == 0) {
2158 list_del_init(&p->list);
2163 mutex_unlock(&ftrace_cmd_mutex);
2168 static int ftrace_process_regex(char *buff, int len, int enable)
2170 char *func, *command, *next = buff;
2171 struct ftrace_func_command *p;
2174 func = strsep(&next, ":");
2177 ftrace_match_records(func, len, enable);
2183 command = strsep(&next, ":");
2185 mutex_lock(&ftrace_cmd_mutex);
2186 list_for_each_entry(p, &ftrace_commands, list) {
2187 if (strcmp(p->name, command) == 0) {
2188 ret = p->func(func, command, next, enable);
2193 mutex_unlock(&ftrace_cmd_mutex);
2199 ftrace_regex_write(struct file *file, const char __user *ubuf,
2200 size_t cnt, loff_t *ppos, int enable)
2202 struct ftrace_iterator *iter;
2203 struct trace_parser *parser;
2209 mutex_lock(&ftrace_regex_lock);
2211 if (file->f_mode & FMODE_READ) {
2212 struct seq_file *m = file->private_data;
2215 iter = file->private_data;
2217 parser = &iter->parser;
2218 read = trace_get_user(parser, ubuf, cnt, ppos);
2220 if (read >= 0 && trace_parser_loaded(parser) &&
2221 !trace_parser_cont(parser)) {
2222 ret = ftrace_process_regex(parser->buffer,
2223 parser->idx, enable);
2227 trace_parser_clear(parser);
2232 mutex_unlock(&ftrace_regex_lock);
2238 ftrace_filter_write(struct file *file, const char __user *ubuf,
2239 size_t cnt, loff_t *ppos)
2241 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
2245 ftrace_notrace_write(struct file *file, const char __user *ubuf,
2246 size_t cnt, loff_t *ppos)
2248 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
2252 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
2254 if (unlikely(ftrace_disabled))
2257 mutex_lock(&ftrace_regex_lock);
2259 ftrace_filter_reset(enable);
2261 ftrace_match_records(buf, len, enable);
2262 mutex_unlock(&ftrace_regex_lock);
2266 * ftrace_set_filter - set a function to filter on in ftrace
2267 * @buf - the string that holds the function filter text.
2268 * @len - the length of the string.
2269 * @reset - non zero to reset all filters before applying this filter.
2271 * Filters denote which functions should be enabled when tracing is enabled.
2272 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2274 void ftrace_set_filter(unsigned char *buf, int len, int reset)
2276 ftrace_set_regex(buf, len, reset, 1);
2280 * ftrace_set_notrace - set a function to not trace in ftrace
2281 * @buf - the string that holds the function notrace text.
2282 * @len - the length of the string.
2283 * @reset - non zero to reset all filters before applying this filter.
2285 * Notrace Filters denote which functions should not be enabled when tracing
2286 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2289 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
2291 ftrace_set_regex(buf, len, reset, 0);
2295 * command line interface to allow users to set filters on boot up.
2297 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
2298 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
2299 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
2301 static int __init set_ftrace_notrace(char *str)
2303 strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
2306 __setup("ftrace_notrace=", set_ftrace_notrace);
2308 static int __init set_ftrace_filter(char *str)
2310 strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
2313 __setup("ftrace_filter=", set_ftrace_filter);
2315 static void __init set_ftrace_early_filter(char *buf, int enable)
2320 func = strsep(&buf, ",");
2321 ftrace_set_regex(func, strlen(func), 0, enable);
2325 static void __init set_ftrace_early_filters(void)
2327 if (ftrace_filter_buf[0])
2328 set_ftrace_early_filter(ftrace_filter_buf, 1);
2329 if (ftrace_notrace_buf[0])
2330 set_ftrace_early_filter(ftrace_notrace_buf, 0);
2334 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
2336 struct seq_file *m = (struct seq_file *)file->private_data;
2337 struct ftrace_iterator *iter;
2338 struct trace_parser *parser;
2340 mutex_lock(&ftrace_regex_lock);
2341 if (file->f_mode & FMODE_READ) {
2344 seq_release(inode, file);
2346 iter = file->private_data;
2348 parser = &iter->parser;
2349 if (trace_parser_loaded(parser)) {
2350 parser->buffer[parser->idx] = 0;
2351 ftrace_match_records(parser->buffer, parser->idx, enable);
2354 mutex_lock(&ftrace_lock);
2355 if (ftrace_start_up && ftrace_enabled)
2356 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
2357 mutex_unlock(&ftrace_lock);
2359 trace_parser_put(parser);
2362 mutex_unlock(&ftrace_regex_lock);
2367 ftrace_filter_release(struct inode *inode, struct file *file)
2369 return ftrace_regex_release(inode, file, 1);
2373 ftrace_notrace_release(struct inode *inode, struct file *file)
2375 return ftrace_regex_release(inode, file, 0);
2378 static const struct file_operations ftrace_avail_fops = {
2379 .open = ftrace_avail_open,
2381 .llseek = seq_lseek,
2382 .release = seq_release_private,
2385 static const struct file_operations ftrace_failures_fops = {
2386 .open = ftrace_failures_open,
2388 .llseek = seq_lseek,
2389 .release = seq_release_private,
2392 static const struct file_operations ftrace_filter_fops = {
2393 .open = ftrace_filter_open,
2395 .write = ftrace_filter_write,
2396 .llseek = ftrace_regex_lseek,
2397 .release = ftrace_filter_release,
2400 static const struct file_operations ftrace_notrace_fops = {
2401 .open = ftrace_notrace_open,
2403 .write = ftrace_notrace_write,
2404 .llseek = ftrace_regex_lseek,
2405 .release = ftrace_notrace_release,
2408 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2410 static DEFINE_MUTEX(graph_lock);
2412 int ftrace_graph_count;
2413 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
2416 __g_next(struct seq_file *m, loff_t *pos)
2418 if (*pos >= ftrace_graph_count)
2420 return &ftrace_graph_funcs[*pos];
2424 g_next(struct seq_file *m, void *v, loff_t *pos)
2427 return __g_next(m, pos);
2430 static void *g_start(struct seq_file *m, loff_t *pos)
2432 mutex_lock(&graph_lock);
2434 /* Nothing, tell g_show to print all functions are enabled */
2435 if (!ftrace_graph_count && !*pos)
2438 return __g_next(m, pos);
2441 static void g_stop(struct seq_file *m, void *p)
2443 mutex_unlock(&graph_lock);
2446 static int g_show(struct seq_file *m, void *v)
2448 unsigned long *ptr = v;
2453 if (ptr == (unsigned long *)1) {
2454 seq_printf(m, "#### all functions enabled ####\n");
2458 seq_printf(m, "%ps\n", (void *)*ptr);
2463 static const struct seq_operations ftrace_graph_seq_ops = {
2471 ftrace_graph_open(struct inode *inode, struct file *file)
2475 if (unlikely(ftrace_disabled))
2478 mutex_lock(&graph_lock);
2479 if ((file->f_mode & FMODE_WRITE) &&
2480 (file->f_flags & O_TRUNC)) {
2481 ftrace_graph_count = 0;
2482 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
2484 mutex_unlock(&graph_lock);
2486 if (file->f_mode & FMODE_READ)
2487 ret = seq_open(file, &ftrace_graph_seq_ops);
2493 ftrace_graph_release(struct inode *inode, struct file *file)
2495 if (file->f_mode & FMODE_READ)
2496 seq_release(inode, file);
2501 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
2503 struct dyn_ftrace *rec;
2504 struct ftrace_page *pg;
2512 if (ftrace_disabled)
2516 type = ftrace_setup_glob(buffer, strlen(buffer), &search, ¬);
2520 search_len = strlen(search);
2522 mutex_lock(&ftrace_lock);
2523 do_for_each_ftrace_rec(pg, rec) {
2525 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
2528 if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
2531 if (ftrace_match_record(rec, search, search_len, type)) {
2532 /* ensure it is not already in the array */
2534 for (i = 0; i < *idx; i++)
2535 if (array[i] == rec->ip) {
2540 array[(*idx)++] = rec->ip;
2544 } while_for_each_ftrace_rec();
2546 mutex_unlock(&ftrace_lock);
2548 return found ? 0 : -EINVAL;
2552 ftrace_graph_write(struct file *file, const char __user *ubuf,
2553 size_t cnt, loff_t *ppos)
2555 struct trace_parser parser;
2558 if (!cnt || cnt < 0)
2561 mutex_lock(&graph_lock);
2563 if (ftrace_graph_count >= FTRACE_GRAPH_MAX_FUNCS) {
2568 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
2573 read = trace_get_user(&parser, ubuf, cnt, ppos);
2575 if (read >= 0 && trace_parser_loaded((&parser))) {
2576 parser.buffer[parser.idx] = 0;
2578 /* we allow only one expression at a time */
2579 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
2588 trace_parser_put(&parser);
2590 mutex_unlock(&graph_lock);
2595 static const struct file_operations ftrace_graph_fops = {
2596 .open = ftrace_graph_open,
2598 .write = ftrace_graph_write,
2599 .release = ftrace_graph_release,
2601 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2603 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
2606 trace_create_file("available_filter_functions", 0444,
2607 d_tracer, NULL, &ftrace_avail_fops);
2609 trace_create_file("failures", 0444,
2610 d_tracer, NULL, &ftrace_failures_fops);
2612 trace_create_file("set_ftrace_filter", 0644, d_tracer,
2613 NULL, &ftrace_filter_fops);
2615 trace_create_file("set_ftrace_notrace", 0644, d_tracer,
2616 NULL, &ftrace_notrace_fops);
2618 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2619 trace_create_file("set_graph_function", 0444, d_tracer,
2621 &ftrace_graph_fops);
2622 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2627 static int ftrace_convert_nops(struct module *mod,
2628 unsigned long *start,
2633 unsigned long flags;
2635 mutex_lock(&ftrace_lock);
2638 addr = ftrace_call_adjust(*p++);
2640 * Some architecture linkers will pad between
2641 * the different mcount_loc sections of different
2642 * object files to satisfy alignments.
2643 * Skip any NULL pointers.
2647 ftrace_record_ip(addr);
2650 /* disable interrupts to prevent kstop machine */
2651 local_irq_save(flags);
2652 ftrace_update_code(mod);
2653 local_irq_restore(flags);
2654 mutex_unlock(&ftrace_lock);
2659 #ifdef CONFIG_MODULES
2660 void ftrace_release_mod(struct module *mod)
2662 struct dyn_ftrace *rec;
2663 struct ftrace_page *pg;
2665 if (ftrace_disabled)
2668 mutex_lock(&ftrace_lock);
2669 do_for_each_ftrace_rec(pg, rec) {
2670 if (within_module_core(rec->ip, mod)) {
2672 * rec->ip is changed in ftrace_free_rec()
2673 * It should not between s and e if record was freed.
2675 FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE);
2676 ftrace_free_rec(rec);
2678 } while_for_each_ftrace_rec();
2679 mutex_unlock(&ftrace_lock);
2682 static void ftrace_init_module(struct module *mod,
2683 unsigned long *start, unsigned long *end)
2685 if (ftrace_disabled || start == end)
2687 ftrace_convert_nops(mod, start, end);
2690 static int ftrace_module_notify(struct notifier_block *self,
2691 unsigned long val, void *data)
2693 struct module *mod = data;
2696 case MODULE_STATE_COMING:
2697 ftrace_init_module(mod, mod->ftrace_callsites,
2698 mod->ftrace_callsites +
2699 mod->num_ftrace_callsites);
2701 case MODULE_STATE_GOING:
2702 ftrace_release_mod(mod);
2709 static int ftrace_module_notify(struct notifier_block *self,
2710 unsigned long val, void *data)
2714 #endif /* CONFIG_MODULES */
2716 struct notifier_block ftrace_module_nb = {
2717 .notifier_call = ftrace_module_notify,
2721 extern unsigned long __start_mcount_loc[];
2722 extern unsigned long __stop_mcount_loc[];
2724 void __init ftrace_init(void)
2726 unsigned long count, addr, flags;
2729 /* Keep the ftrace pointer to the stub */
2730 addr = (unsigned long)ftrace_stub;
2732 local_irq_save(flags);
2733 ftrace_dyn_arch_init(&addr);
2734 local_irq_restore(flags);
2736 /* ftrace_dyn_arch_init places the return code in addr */
2740 count = __stop_mcount_loc - __start_mcount_loc;
2742 ret = ftrace_dyn_table_alloc(count);
2746 last_ftrace_enabled = ftrace_enabled = 1;
2748 ret = ftrace_convert_nops(NULL,
2752 ret = register_module_notifier(&ftrace_module_nb);
2754 pr_warning("Failed to register trace ftrace module notifier\n");
2756 set_ftrace_early_filters();
2760 ftrace_disabled = 1;
2765 static int __init ftrace_nodyn_init(void)
2770 device_initcall(ftrace_nodyn_init);
2772 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
2773 static inline void ftrace_startup_enable(int command) { }
2774 /* Keep as macros so we do not need to define the commands */
2775 # define ftrace_startup(command) do { } while (0)
2776 # define ftrace_shutdown(command) do { } while (0)
2777 # define ftrace_startup_sysctl() do { } while (0)
2778 # define ftrace_shutdown_sysctl() do { } while (0)
2779 #endif /* CONFIG_DYNAMIC_FTRACE */
2782 ftrace_pid_read(struct file *file, char __user *ubuf,
2783 size_t cnt, loff_t *ppos)
2788 if (ftrace_pid_trace == ftrace_swapper_pid)
2789 r = sprintf(buf, "swapper tasks\n");
2790 else if (ftrace_pid_trace)
2791 r = sprintf(buf, "%u\n", pid_vnr(ftrace_pid_trace));
2793 r = sprintf(buf, "no pid\n");
2795 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2798 static void clear_ftrace_swapper(void)
2800 struct task_struct *p;
2804 for_each_online_cpu(cpu) {
2806 clear_tsk_trace_trace(p);
2811 static void set_ftrace_swapper(void)
2813 struct task_struct *p;
2817 for_each_online_cpu(cpu) {
2819 set_tsk_trace_trace(p);
2824 static void clear_ftrace_pid(struct pid *pid)
2826 struct task_struct *p;
2829 do_each_pid_task(pid, PIDTYPE_PID, p) {
2830 clear_tsk_trace_trace(p);
2831 } while_each_pid_task(pid, PIDTYPE_PID, p);
2837 static void set_ftrace_pid(struct pid *pid)
2839 struct task_struct *p;
2842 do_each_pid_task(pid, PIDTYPE_PID, p) {
2843 set_tsk_trace_trace(p);
2844 } while_each_pid_task(pid, PIDTYPE_PID, p);
2848 static void clear_ftrace_pid_task(struct pid **pid)
2850 if (*pid == ftrace_swapper_pid)
2851 clear_ftrace_swapper();
2853 clear_ftrace_pid(*pid);
2858 static void set_ftrace_pid_task(struct pid *pid)
2860 if (pid == ftrace_swapper_pid)
2861 set_ftrace_swapper();
2863 set_ftrace_pid(pid);
2867 ftrace_pid_write(struct file *filp, const char __user *ubuf,
2868 size_t cnt, loff_t *ppos)
2875 if (cnt >= sizeof(buf))
2878 if (copy_from_user(&buf, ubuf, cnt))
2883 ret = strict_strtol(buf, 10, &val);
2887 mutex_lock(&ftrace_lock);
2889 /* disable pid tracing */
2890 if (!ftrace_pid_trace)
2893 clear_ftrace_pid_task(&ftrace_pid_trace);
2896 /* swapper task is special */
2898 pid = ftrace_swapper_pid;
2899 if (pid == ftrace_pid_trace)
2902 pid = find_get_pid(val);
2904 if (pid == ftrace_pid_trace) {
2910 if (ftrace_pid_trace)
2911 clear_ftrace_pid_task(&ftrace_pid_trace);
2916 ftrace_pid_trace = pid;
2918 set_ftrace_pid_task(ftrace_pid_trace);
2921 /* update the function call */
2922 ftrace_update_pid_func();
2923 ftrace_startup_enable(0);
2926 mutex_unlock(&ftrace_lock);
2931 static const struct file_operations ftrace_pid_fops = {
2932 .read = ftrace_pid_read,
2933 .write = ftrace_pid_write,
2936 static __init int ftrace_init_debugfs(void)
2938 struct dentry *d_tracer;
2940 d_tracer = tracing_init_dentry();
2944 ftrace_init_dyn_debugfs(d_tracer);
2946 trace_create_file("set_ftrace_pid", 0644, d_tracer,
2947 NULL, &ftrace_pid_fops);
2949 ftrace_profile_debugfs(d_tracer);
2953 fs_initcall(ftrace_init_debugfs);
2956 * ftrace_kill - kill ftrace
2958 * This function should be used by panic code. It stops ftrace
2959 * but in a not so nice way. If you need to simply kill ftrace
2960 * from a non-atomic section, use ftrace_kill.
2962 void ftrace_kill(void)
2964 ftrace_disabled = 1;
2966 clear_ftrace_function();
2970 * register_ftrace_function - register a function for profiling
2971 * @ops - ops structure that holds the function for profiling.
2973 * Register a function to be called by all functions in the
2976 * Note: @ops->func and all the functions it calls must be labeled
2977 * with "notrace", otherwise it will go into a
2980 int register_ftrace_function(struct ftrace_ops *ops)
2984 if (unlikely(ftrace_disabled))
2987 mutex_lock(&ftrace_lock);
2989 ret = __register_ftrace_function(ops);
2992 mutex_unlock(&ftrace_lock);
2997 * unregister_ftrace_function - unregister a function for profiling.
2998 * @ops - ops structure that holds the function to unregister
3000 * Unregister a function that was added to be called by ftrace profiling.
3002 int unregister_ftrace_function(struct ftrace_ops *ops)
3006 mutex_lock(&ftrace_lock);
3007 ret = __unregister_ftrace_function(ops);
3009 mutex_unlock(&ftrace_lock);
3015 ftrace_enable_sysctl(struct ctl_table *table, int write,
3016 void __user *buffer, size_t *lenp,
3021 if (unlikely(ftrace_disabled))
3024 mutex_lock(&ftrace_lock);
3026 ret = proc_dointvec(table, write, buffer, lenp, ppos);
3028 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
3031 last_ftrace_enabled = !!ftrace_enabled;
3033 if (ftrace_enabled) {
3035 ftrace_startup_sysctl();
3037 /* we are starting ftrace again */
3038 if (ftrace_list != &ftrace_list_end) {
3039 if (ftrace_list->next == &ftrace_list_end)
3040 ftrace_trace_function = ftrace_list->func;
3042 ftrace_trace_function = ftrace_list_func;
3046 /* stopping ftrace calls (just send to ftrace_stub) */
3047 ftrace_trace_function = ftrace_stub;
3049 ftrace_shutdown_sysctl();
3053 mutex_unlock(&ftrace_lock);
3057 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3059 static int ftrace_graph_active;
3060 static struct notifier_block ftrace_suspend_notifier;
3062 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
3067 /* The callbacks that hook a function */
3068 trace_func_graph_ret_t ftrace_graph_return =
3069 (trace_func_graph_ret_t)ftrace_stub;
3070 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
3072 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
3073 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
3077 unsigned long flags;
3078 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
3079 struct task_struct *g, *t;
3081 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
3082 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
3083 * sizeof(struct ftrace_ret_stack),
3085 if (!ret_stack_list[i]) {
3093 read_lock_irqsave(&tasklist_lock, flags);
3094 do_each_thread(g, t) {
3100 if (t->ret_stack == NULL) {
3101 atomic_set(&t->tracing_graph_pause, 0);
3102 atomic_set(&t->trace_overrun, 0);
3103 t->curr_ret_stack = -1;
3104 /* Make sure the tasks see the -1 first: */
3106 t->ret_stack = ret_stack_list[start++];
3108 } while_each_thread(g, t);
3111 read_unlock_irqrestore(&tasklist_lock, flags);
3113 for (i = start; i < end; i++)
3114 kfree(ret_stack_list[i]);
3119 ftrace_graph_probe_sched_switch(struct rq *__rq, struct task_struct *prev,
3120 struct task_struct *next)
3122 unsigned long long timestamp;
3126 * Does the user want to count the time a function was asleep.
3127 * If so, do not update the time stamps.
3129 if (trace_flags & TRACE_ITER_SLEEP_TIME)
3132 timestamp = trace_clock_local();
3134 prev->ftrace_timestamp = timestamp;
3136 /* only process tasks that we timestamped */
3137 if (!next->ftrace_timestamp)
3141 * Update all the counters in next to make up for the
3142 * time next was sleeping.
3144 timestamp -= next->ftrace_timestamp;
3146 for (index = next->curr_ret_stack; index >= 0; index--)
3147 next->ret_stack[index].calltime += timestamp;
3150 /* Allocate a return stack for each task */
3151 static int start_graph_tracing(void)
3153 struct ftrace_ret_stack **ret_stack_list;
3156 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
3157 sizeof(struct ftrace_ret_stack *),
3160 if (!ret_stack_list)
3163 /* The cpu_boot init_task->ret_stack will never be freed */
3164 for_each_online_cpu(cpu) {
3165 if (!idle_task(cpu)->ret_stack)
3166 ftrace_graph_init_task(idle_task(cpu));
3170 ret = alloc_retstack_tasklist(ret_stack_list);
3171 } while (ret == -EAGAIN);
3174 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch);
3176 pr_info("ftrace_graph: Couldn't activate tracepoint"
3177 " probe to kernel_sched_switch\n");
3180 kfree(ret_stack_list);
3185 * Hibernation protection.
3186 * The state of the current task is too much unstable during
3187 * suspend/restore to disk. We want to protect against that.
3190 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
3194 case PM_HIBERNATION_PREPARE:
3195 pause_graph_tracing();
3198 case PM_POST_HIBERNATION:
3199 unpause_graph_tracing();
3205 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
3206 trace_func_graph_ent_t entryfunc)
3210 mutex_lock(&ftrace_lock);
3212 /* we currently allow only one tracer registered at a time */
3213 if (ftrace_graph_active) {
3218 ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
3219 register_pm_notifier(&ftrace_suspend_notifier);
3221 ftrace_graph_active++;
3222 ret = start_graph_tracing();
3224 ftrace_graph_active--;
3228 ftrace_graph_return = retfunc;
3229 ftrace_graph_entry = entryfunc;
3231 ftrace_startup(FTRACE_START_FUNC_RET);
3234 mutex_unlock(&ftrace_lock);
3238 void unregister_ftrace_graph(void)
3240 mutex_lock(&ftrace_lock);
3242 if (unlikely(!ftrace_graph_active))
3245 ftrace_graph_active--;
3246 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch);
3247 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
3248 ftrace_graph_entry = ftrace_graph_entry_stub;
3249 ftrace_shutdown(FTRACE_STOP_FUNC_RET);
3250 unregister_pm_notifier(&ftrace_suspend_notifier);
3253 mutex_unlock(&ftrace_lock);
3256 /* Allocate a return stack for newly created task */
3257 void ftrace_graph_init_task(struct task_struct *t)
3259 /* Make sure we do not use the parent ret_stack */
3260 t->ret_stack = NULL;
3262 if (ftrace_graph_active) {
3263 struct ftrace_ret_stack *ret_stack;
3265 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
3266 * sizeof(struct ftrace_ret_stack),
3270 t->curr_ret_stack = -1;
3271 atomic_set(&t->tracing_graph_pause, 0);
3272 atomic_set(&t->trace_overrun, 0);
3273 t->ftrace_timestamp = 0;
3274 /* make curr_ret_stack visable before we add the ret_stack */
3276 t->ret_stack = ret_stack;
3280 void ftrace_graph_exit_task(struct task_struct *t)
3282 struct ftrace_ret_stack *ret_stack = t->ret_stack;
3284 t->ret_stack = NULL;
3285 /* NULL must become visible to IRQs before we free it: */
3291 void ftrace_graph_stop(void)