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 func = ftrace_trace_function;
230 if (ftrace_pid_trace) {
231 set_ftrace_pid_function(func);
232 func = ftrace_pid_func;
234 if (func == ftrace_pid_func)
235 func = ftrace_pid_function;
238 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
239 ftrace_trace_function = func;
241 __ftrace_trace_function = func;
245 #ifdef CONFIG_FUNCTION_PROFILER
246 struct ftrace_profile {
247 struct hlist_node node;
249 unsigned long counter;
250 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
251 unsigned long long time;
255 struct ftrace_profile_page {
256 struct ftrace_profile_page *next;
258 struct ftrace_profile records[];
261 struct ftrace_profile_stat {
263 struct hlist_head *hash;
264 struct ftrace_profile_page *pages;
265 struct ftrace_profile_page *start;
266 struct tracer_stat stat;
269 #define PROFILE_RECORDS_SIZE \
270 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
272 #define PROFILES_PER_PAGE \
273 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
275 static int ftrace_profile_bits __read_mostly;
276 static int ftrace_profile_enabled __read_mostly;
278 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
279 static DEFINE_MUTEX(ftrace_profile_lock);
281 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
283 #define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
286 function_stat_next(void *v, int idx)
288 struct ftrace_profile *rec = v;
289 struct ftrace_profile_page *pg;
291 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
295 if ((void *)rec >= (void *)&pg->records[pg->index]) {
299 rec = &pg->records[0];
307 static void *function_stat_start(struct tracer_stat *trace)
309 struct ftrace_profile_stat *stat =
310 container_of(trace, struct ftrace_profile_stat, stat);
312 if (!stat || !stat->start)
315 return function_stat_next(&stat->start->records[0], 0);
318 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
319 /* function graph compares on total time */
320 static int function_stat_cmp(void *p1, void *p2)
322 struct ftrace_profile *a = p1;
323 struct ftrace_profile *b = p2;
325 if (a->time < b->time)
327 if (a->time > b->time)
333 /* not function graph compares against hits */
334 static int function_stat_cmp(void *p1, void *p2)
336 struct ftrace_profile *a = p1;
337 struct ftrace_profile *b = p2;
339 if (a->counter < b->counter)
341 if (a->counter > b->counter)
348 static int function_stat_headers(struct seq_file *m)
350 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
351 seq_printf(m, " Function "
356 seq_printf(m, " Function Hit\n"
362 static int function_stat_show(struct seq_file *m, void *v)
364 struct ftrace_profile *rec = v;
365 char str[KSYM_SYMBOL_LEN];
366 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
367 static DEFINE_MUTEX(mutex);
368 static struct trace_seq s;
369 unsigned long long avg;
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
378 do_div(avg, rec->counter);
382 trace_print_graph_duration(rec->time, &s);
383 trace_seq_puts(&s, " ");
384 trace_print_graph_duration(avg, &s);
385 trace_print_seq(m, &s);
386 mutex_unlock(&mutex);
393 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
395 struct ftrace_profile_page *pg;
397 pg = stat->pages = stat->start;
400 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
405 memset(stat->hash, 0,
406 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
409 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
411 struct ftrace_profile_page *pg;
416 /* If we already allocated, do nothing */
420 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
424 #ifdef CONFIG_DYNAMIC_FTRACE
425 functions = ftrace_update_tot_cnt;
428 * We do not know the number of functions that exist because
429 * dynamic tracing is what counts them. With past experience
430 * we have around 20K functions. That should be more than enough.
431 * It is highly unlikely we will execute every function in
437 pg = stat->start = stat->pages;
439 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
441 for (i = 0; i < pages; i++) {
442 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
453 unsigned long tmp = (unsigned long)pg;
459 free_page((unsigned long)stat->pages);
466 static int ftrace_profile_init_cpu(int cpu)
468 struct ftrace_profile_stat *stat;
471 stat = &per_cpu(ftrace_profile_stats, cpu);
474 /* If the profile is already created, simply reset it */
475 ftrace_profile_reset(stat);
480 * We are profiling all functions, but usually only a few thousand
481 * functions are hit. We'll make a hash of 1024 items.
483 size = FTRACE_PROFILE_HASH_SIZE;
485 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
490 if (!ftrace_profile_bits) {
493 for (; size; size >>= 1)
494 ftrace_profile_bits++;
497 /* Preallocate the function profiling pages */
498 if (ftrace_profile_pages_init(stat) < 0) {
507 static int ftrace_profile_init(void)
512 for_each_online_cpu(cpu) {
513 ret = ftrace_profile_init_cpu(cpu);
521 /* interrupts must be disabled */
522 static struct ftrace_profile *
523 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
525 struct ftrace_profile *rec;
526 struct hlist_head *hhd;
527 struct hlist_node *n;
530 key = hash_long(ip, ftrace_profile_bits);
531 hhd = &stat->hash[key];
533 if (hlist_empty(hhd))
536 hlist_for_each_entry_rcu(rec, n, hhd, node) {
544 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
545 struct ftrace_profile *rec)
549 key = hash_long(rec->ip, ftrace_profile_bits);
550 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
554 * The memory is already allocated, this simply finds a new record to use.
556 static struct ftrace_profile *
557 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
559 struct ftrace_profile *rec = NULL;
561 /* prevent recursion (from NMIs) */
562 if (atomic_inc_return(&stat->disabled) != 1)
566 * Try to find the function again since an NMI
567 * could have added it
569 rec = ftrace_find_profiled_func(stat, ip);
573 if (stat->pages->index == PROFILES_PER_PAGE) {
574 if (!stat->pages->next)
576 stat->pages = stat->pages->next;
579 rec = &stat->pages->records[stat->pages->index++];
581 ftrace_add_profile(stat, rec);
584 atomic_dec(&stat->disabled);
590 function_profile_call(unsigned long ip, unsigned long parent_ip)
592 struct ftrace_profile_stat *stat;
593 struct ftrace_profile *rec;
596 if (!ftrace_profile_enabled)
599 local_irq_save(flags);
601 stat = &__get_cpu_var(ftrace_profile_stats);
602 if (!stat->hash || !ftrace_profile_enabled)
605 rec = ftrace_find_profiled_func(stat, ip);
607 rec = ftrace_profile_alloc(stat, ip);
614 local_irq_restore(flags);
617 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
618 static int profile_graph_entry(struct ftrace_graph_ent *trace)
620 function_profile_call(trace->func, 0);
624 static void profile_graph_return(struct ftrace_graph_ret *trace)
626 struct ftrace_profile_stat *stat;
627 unsigned long long calltime;
628 struct ftrace_profile *rec;
631 local_irq_save(flags);
632 stat = &__get_cpu_var(ftrace_profile_stats);
633 if (!stat->hash || !ftrace_profile_enabled)
636 calltime = trace->rettime - trace->calltime;
638 if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
641 index = trace->depth;
643 /* Append this call time to the parent time to subtract */
645 current->ret_stack[index - 1].subtime += calltime;
647 if (current->ret_stack[index].subtime < calltime)
648 calltime -= current->ret_stack[index].subtime;
653 rec = ftrace_find_profiled_func(stat, trace->func);
655 rec->time += calltime;
658 local_irq_restore(flags);
661 static int register_ftrace_profiler(void)
663 return register_ftrace_graph(&profile_graph_return,
664 &profile_graph_entry);
667 static void unregister_ftrace_profiler(void)
669 unregister_ftrace_graph();
672 static struct ftrace_ops ftrace_profile_ops __read_mostly =
674 .func = function_profile_call,
677 static int register_ftrace_profiler(void)
679 return register_ftrace_function(&ftrace_profile_ops);
682 static void unregister_ftrace_profiler(void)
684 unregister_ftrace_function(&ftrace_profile_ops);
686 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
689 ftrace_profile_write(struct file *filp, const char __user *ubuf,
690 size_t cnt, loff_t *ppos)
693 char buf[64]; /* big enough to hold a number */
696 if (cnt >= sizeof(buf))
699 if (copy_from_user(&buf, ubuf, cnt))
704 ret = strict_strtoul(buf, 10, &val);
710 mutex_lock(&ftrace_profile_lock);
711 if (ftrace_profile_enabled ^ val) {
713 ret = ftrace_profile_init();
719 ret = register_ftrace_profiler();
724 ftrace_profile_enabled = 1;
726 ftrace_profile_enabled = 0;
728 * unregister_ftrace_profiler calls stop_machine
729 * so this acts like an synchronize_sched.
731 unregister_ftrace_profiler();
735 mutex_unlock(&ftrace_profile_lock);
743 ftrace_profile_read(struct file *filp, char __user *ubuf,
744 size_t cnt, loff_t *ppos)
746 char buf[64]; /* big enough to hold a number */
749 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
750 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
753 static const struct file_operations ftrace_profile_fops = {
754 .open = tracing_open_generic,
755 .read = ftrace_profile_read,
756 .write = ftrace_profile_write,
759 /* used to initialize the real stat files */
760 static struct tracer_stat function_stats __initdata = {
762 .stat_start = function_stat_start,
763 .stat_next = function_stat_next,
764 .stat_cmp = function_stat_cmp,
765 .stat_headers = function_stat_headers,
766 .stat_show = function_stat_show
769 static void ftrace_profile_debugfs(struct dentry *d_tracer)
771 struct ftrace_profile_stat *stat;
772 struct dentry *entry;
777 for_each_possible_cpu(cpu) {
778 stat = &per_cpu(ftrace_profile_stats, cpu);
780 /* allocate enough for function name + cpu number */
781 name = kmalloc(32, GFP_KERNEL);
784 * The files created are permanent, if something happens
785 * we still do not free memory.
789 "Could not allocate stat file for cpu %d\n",
793 stat->stat = function_stats;
794 snprintf(name, 32, "function%d", cpu);
795 stat->stat.name = name;
796 ret = register_stat_tracer(&stat->stat);
799 "Could not register function stat for cpu %d\n",
806 entry = debugfs_create_file("function_profile_enabled", 0644,
807 d_tracer, NULL, &ftrace_profile_fops);
809 pr_warning("Could not create debugfs "
810 "'function_profile_enabled' entry\n");
813 #else /* CONFIG_FUNCTION_PROFILER */
814 static void ftrace_profile_debugfs(struct dentry *d_tracer)
817 #endif /* CONFIG_FUNCTION_PROFILER */
819 /* set when tracing only a pid */
820 struct pid *ftrace_pid_trace;
821 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
823 #ifdef CONFIG_DYNAMIC_FTRACE
825 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
826 # error Dynamic ftrace depends on MCOUNT_RECORD
829 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
831 struct ftrace_func_probe {
832 struct hlist_node node;
833 struct ftrace_probe_ops *ops;
841 FTRACE_ENABLE_CALLS = (1 << 0),
842 FTRACE_DISABLE_CALLS = (1 << 1),
843 FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
844 FTRACE_ENABLE_MCOUNT = (1 << 3),
845 FTRACE_DISABLE_MCOUNT = (1 << 4),
846 FTRACE_START_FUNC_RET = (1 << 5),
847 FTRACE_STOP_FUNC_RET = (1 << 6),
850 static int ftrace_filtered;
852 static struct dyn_ftrace *ftrace_new_addrs;
854 static DEFINE_MUTEX(ftrace_regex_lock);
857 struct ftrace_page *next;
859 struct dyn_ftrace records[];
862 #define ENTRIES_PER_PAGE \
863 ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
865 /* estimate from running different kernels */
866 #define NR_TO_INIT 10000
868 static struct ftrace_page *ftrace_pages_start;
869 static struct ftrace_page *ftrace_pages;
871 static struct dyn_ftrace *ftrace_free_records;
874 * This is a double for. Do not use 'break' to break out of the loop,
875 * you must use a goto.
877 #define do_for_each_ftrace_rec(pg, rec) \
878 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
880 for (_____i = 0; _____i < pg->index; _____i++) { \
881 rec = &pg->records[_____i];
883 #define while_for_each_ftrace_rec() \
887 #ifdef CONFIG_KPROBES
889 static int frozen_record_count;
891 static inline void freeze_record(struct dyn_ftrace *rec)
893 if (!(rec->flags & FTRACE_FL_FROZEN)) {
894 rec->flags |= FTRACE_FL_FROZEN;
895 frozen_record_count++;
899 static inline void unfreeze_record(struct dyn_ftrace *rec)
901 if (rec->flags & FTRACE_FL_FROZEN) {
902 rec->flags &= ~FTRACE_FL_FROZEN;
903 frozen_record_count--;
907 static inline int record_frozen(struct dyn_ftrace *rec)
909 return rec->flags & FTRACE_FL_FROZEN;
912 # define freeze_record(rec) ({ 0; })
913 # define unfreeze_record(rec) ({ 0; })
914 # define record_frozen(rec) ({ 0; })
915 #endif /* CONFIG_KPROBES */
917 static void ftrace_free_rec(struct dyn_ftrace *rec)
919 rec->freelist = ftrace_free_records;
920 ftrace_free_records = rec;
921 rec->flags |= FTRACE_FL_FREE;
924 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
926 struct dyn_ftrace *rec;
928 /* First check for freed records */
929 if (ftrace_free_records) {
930 rec = ftrace_free_records;
932 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
933 FTRACE_WARN_ON_ONCE(1);
934 ftrace_free_records = NULL;
938 ftrace_free_records = rec->freelist;
939 memset(rec, 0, sizeof(*rec));
943 if (ftrace_pages->index == ENTRIES_PER_PAGE) {
944 if (!ftrace_pages->next) {
945 /* allocate another page */
947 (void *)get_zeroed_page(GFP_KERNEL);
948 if (!ftrace_pages->next)
951 ftrace_pages = ftrace_pages->next;
954 return &ftrace_pages->records[ftrace_pages->index++];
957 static struct dyn_ftrace *
958 ftrace_record_ip(unsigned long ip)
960 struct dyn_ftrace *rec;
965 rec = ftrace_alloc_dyn_node(ip);
970 rec->newlist = ftrace_new_addrs;
971 ftrace_new_addrs = rec;
976 static void print_ip_ins(const char *fmt, unsigned char *p)
980 printk(KERN_CONT "%s", fmt);
982 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
983 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
986 static void ftrace_bug(int failed, unsigned long ip)
990 FTRACE_WARN_ON_ONCE(1);
991 pr_info("ftrace faulted on modifying ");
995 FTRACE_WARN_ON_ONCE(1);
996 pr_info("ftrace failed to modify ");
998 print_ip_ins(" actual: ", (unsigned char *)ip);
999 printk(KERN_CONT "\n");
1002 FTRACE_WARN_ON_ONCE(1);
1003 pr_info("ftrace faulted on writing ");
1007 FTRACE_WARN_ON_ONCE(1);
1008 pr_info("ftrace faulted on unknown error ");
1015 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1017 unsigned long ftrace_addr;
1018 unsigned long ip, fl;
1020 ftrace_addr = (unsigned long)FTRACE_ADDR;
1025 * If this record is not to be traced and
1026 * it is not enabled then do nothing.
1028 * If this record is not to be traced and
1029 * it is enabled then disable it.
1032 if (rec->flags & FTRACE_FL_NOTRACE) {
1033 if (rec->flags & FTRACE_FL_ENABLED)
1034 rec->flags &= ~FTRACE_FL_ENABLED;
1038 } else if (ftrace_filtered && enable) {
1043 fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED);
1045 /* Record is filtered and enabled, do nothing */
1046 if (fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED))
1049 /* Record is not filtered or enabled, do nothing */
1053 /* Record is not filtered but enabled, disable it */
1054 if (fl == FTRACE_FL_ENABLED)
1055 rec->flags &= ~FTRACE_FL_ENABLED;
1057 /* Otherwise record is filtered but not enabled, enable it */
1058 rec->flags |= FTRACE_FL_ENABLED;
1060 /* Disable or not filtered */
1063 /* if record is enabled, do nothing */
1064 if (rec->flags & FTRACE_FL_ENABLED)
1067 rec->flags |= FTRACE_FL_ENABLED;
1071 /* if record is not enabled, do nothing */
1072 if (!(rec->flags & FTRACE_FL_ENABLED))
1075 rec->flags &= ~FTRACE_FL_ENABLED;
1079 if (rec->flags & FTRACE_FL_ENABLED)
1080 return ftrace_make_call(rec, ftrace_addr);
1082 return ftrace_make_nop(NULL, rec, ftrace_addr);
1085 static void ftrace_replace_code(int enable)
1087 struct dyn_ftrace *rec;
1088 struct ftrace_page *pg;
1091 do_for_each_ftrace_rec(pg, rec) {
1093 * Skip over free records, records that have
1094 * failed and not converted.
1096 if (rec->flags & FTRACE_FL_FREE ||
1097 rec->flags & FTRACE_FL_FAILED ||
1098 !(rec->flags & FTRACE_FL_CONVERTED))
1101 /* ignore updates to this record's mcount site */
1102 if (get_kprobe((void *)rec->ip)) {
1106 unfreeze_record(rec);
1109 failed = __ftrace_replace_code(rec, enable);
1111 rec->flags |= FTRACE_FL_FAILED;
1112 if ((system_state == SYSTEM_BOOTING) ||
1113 !core_kernel_text(rec->ip)) {
1114 ftrace_free_rec(rec);
1116 ftrace_bug(failed, rec->ip);
1117 /* Stop processing */
1121 } while_for_each_ftrace_rec();
1125 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1132 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1134 ftrace_bug(ret, ip);
1135 rec->flags |= FTRACE_FL_FAILED;
1142 * archs can override this function if they must do something
1143 * before the modifying code is performed.
1145 int __weak ftrace_arch_code_modify_prepare(void)
1151 * archs can override this function if they must do something
1152 * after the modifying code is performed.
1154 int __weak ftrace_arch_code_modify_post_process(void)
1159 static int __ftrace_modify_code(void *data)
1161 int *command = data;
1163 if (*command & FTRACE_ENABLE_CALLS)
1164 ftrace_replace_code(1);
1165 else if (*command & FTRACE_DISABLE_CALLS)
1166 ftrace_replace_code(0);
1168 if (*command & FTRACE_UPDATE_TRACE_FUNC)
1169 ftrace_update_ftrace_func(ftrace_trace_function);
1171 if (*command & FTRACE_START_FUNC_RET)
1172 ftrace_enable_ftrace_graph_caller();
1173 else if (*command & FTRACE_STOP_FUNC_RET)
1174 ftrace_disable_ftrace_graph_caller();
1179 static void ftrace_run_update_code(int command)
1183 ret = ftrace_arch_code_modify_prepare();
1184 FTRACE_WARN_ON(ret);
1188 stop_machine(__ftrace_modify_code, &command, NULL);
1190 ret = ftrace_arch_code_modify_post_process();
1191 FTRACE_WARN_ON(ret);
1194 static ftrace_func_t saved_ftrace_func;
1195 static int ftrace_start_up;
1197 static void ftrace_startup_enable(int command)
1199 if (saved_ftrace_func != ftrace_trace_function) {
1200 saved_ftrace_func = ftrace_trace_function;
1201 command |= FTRACE_UPDATE_TRACE_FUNC;
1204 if (!command || !ftrace_enabled)
1207 ftrace_run_update_code(command);
1210 static void ftrace_startup(int command)
1212 if (unlikely(ftrace_disabled))
1216 command |= FTRACE_ENABLE_CALLS;
1218 ftrace_startup_enable(command);
1221 static void ftrace_shutdown(int command)
1223 if (unlikely(ftrace_disabled))
1228 * Just warn in case of unbalance, no need to kill ftrace, it's not
1229 * critical but the ftrace_call callers may be never nopped again after
1230 * further ftrace uses.
1232 WARN_ON_ONCE(ftrace_start_up < 0);
1234 if (!ftrace_start_up)
1235 command |= FTRACE_DISABLE_CALLS;
1237 if (saved_ftrace_func != ftrace_trace_function) {
1238 saved_ftrace_func = ftrace_trace_function;
1239 command |= FTRACE_UPDATE_TRACE_FUNC;
1242 if (!command || !ftrace_enabled)
1245 ftrace_run_update_code(command);
1248 static void ftrace_startup_sysctl(void)
1250 int command = FTRACE_ENABLE_MCOUNT;
1252 if (unlikely(ftrace_disabled))
1255 /* Force update next time */
1256 saved_ftrace_func = NULL;
1257 /* ftrace_start_up is true if we want ftrace running */
1258 if (ftrace_start_up)
1259 command |= FTRACE_ENABLE_CALLS;
1261 ftrace_run_update_code(command);
1264 static void ftrace_shutdown_sysctl(void)
1266 int command = FTRACE_DISABLE_MCOUNT;
1268 if (unlikely(ftrace_disabled))
1271 /* ftrace_start_up is true if ftrace is running */
1272 if (ftrace_start_up)
1273 command |= FTRACE_DISABLE_CALLS;
1275 ftrace_run_update_code(command);
1278 static cycle_t ftrace_update_time;
1279 static unsigned long ftrace_update_cnt;
1280 unsigned long ftrace_update_tot_cnt;
1282 static int ftrace_update_code(struct module *mod)
1284 struct dyn_ftrace *p;
1285 cycle_t start, stop;
1287 start = ftrace_now(raw_smp_processor_id());
1288 ftrace_update_cnt = 0;
1290 while (ftrace_new_addrs) {
1292 /* If something went wrong, bail without enabling anything */
1293 if (unlikely(ftrace_disabled))
1296 p = ftrace_new_addrs;
1297 ftrace_new_addrs = p->newlist;
1300 /* convert record (i.e, patch mcount-call with NOP) */
1301 if (ftrace_code_disable(mod, p)) {
1302 p->flags |= FTRACE_FL_CONVERTED;
1303 ftrace_update_cnt++;
1308 stop = ftrace_now(raw_smp_processor_id());
1309 ftrace_update_time = stop - start;
1310 ftrace_update_tot_cnt += ftrace_update_cnt;
1315 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
1317 struct ftrace_page *pg;
1321 /* allocate a few pages */
1322 ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
1323 if (!ftrace_pages_start)
1327 * Allocate a few more pages.
1329 * TODO: have some parser search vmlinux before
1330 * final linking to find all calls to ftrace.
1332 * a) know how many pages to allocate.
1334 * b) set up the table then.
1336 * The dynamic code is still necessary for
1340 pg = ftrace_pages = ftrace_pages_start;
1342 cnt = num_to_init / ENTRIES_PER_PAGE;
1343 pr_info("ftrace: allocating %ld entries in %d pages\n",
1344 num_to_init, cnt + 1);
1346 for (i = 0; i < cnt; i++) {
1347 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
1349 /* If we fail, we'll try later anyway */
1360 FTRACE_ITER_FILTER = (1 << 0),
1361 FTRACE_ITER_CONT = (1 << 1),
1362 FTRACE_ITER_NOTRACE = (1 << 2),
1363 FTRACE_ITER_FAILURES = (1 << 3),
1364 FTRACE_ITER_PRINTALL = (1 << 4),
1365 FTRACE_ITER_HASH = (1 << 5),
1368 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
1370 struct ftrace_iterator {
1371 struct ftrace_page *pg;
1375 unsigned char buffer[FTRACE_BUFF_MAX+1];
1376 unsigned buffer_idx;
1381 t_hash_next(struct seq_file *m, void *v, loff_t *pos)
1383 struct ftrace_iterator *iter = m->private;
1384 struct hlist_node *hnd = v;
1385 struct hlist_head *hhd;
1387 WARN_ON(!(iter->flags & FTRACE_ITER_HASH));
1392 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
1395 hhd = &ftrace_func_hash[iter->hidx];
1397 if (hlist_empty(hhd)) {
1416 static void *t_hash_start(struct seq_file *m, loff_t *pos)
1418 struct ftrace_iterator *iter = m->private;
1421 iter->flags |= FTRACE_ITER_HASH;
1423 return t_hash_next(m, p, pos);
1426 static int t_hash_show(struct seq_file *m, void *v)
1428 struct ftrace_func_probe *rec;
1429 struct hlist_node *hnd = v;
1430 char str[KSYM_SYMBOL_LEN];
1432 rec = hlist_entry(hnd, struct ftrace_func_probe, node);
1434 if (rec->ops->print)
1435 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
1437 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1438 seq_printf(m, "%s:", str);
1440 kallsyms_lookup((unsigned long)rec->ops->func, NULL, NULL, NULL, str);
1441 seq_printf(m, "%s", str);
1444 seq_printf(m, ":%p", rec->data);
1451 t_next(struct seq_file *m, void *v, loff_t *pos)
1453 struct ftrace_iterator *iter = m->private;
1454 struct dyn_ftrace *rec = NULL;
1456 if (iter->flags & FTRACE_ITER_HASH)
1457 return t_hash_next(m, v, pos);
1461 if (iter->flags & FTRACE_ITER_PRINTALL)
1465 if (iter->idx >= iter->pg->index) {
1466 if (iter->pg->next) {
1467 iter->pg = iter->pg->next;
1472 rec = &iter->pg->records[iter->idx++];
1473 if ((rec->flags & FTRACE_FL_FREE) ||
1475 (!(iter->flags & FTRACE_ITER_FAILURES) &&
1476 (rec->flags & FTRACE_FL_FAILED)) ||
1478 ((iter->flags & FTRACE_ITER_FAILURES) &&
1479 !(rec->flags & FTRACE_FL_FAILED)) ||
1481 ((iter->flags & FTRACE_ITER_FILTER) &&
1482 !(rec->flags & FTRACE_FL_FILTER)) ||
1484 ((iter->flags & FTRACE_ITER_NOTRACE) &&
1485 !(rec->flags & FTRACE_FL_NOTRACE))) {
1494 static void *t_start(struct seq_file *m, loff_t *pos)
1496 struct ftrace_iterator *iter = m->private;
1500 mutex_lock(&ftrace_lock);
1502 * For set_ftrace_filter reading, if we have the filter
1503 * off, we can short cut and just print out that all
1504 * functions are enabled.
1506 if (iter->flags & FTRACE_ITER_FILTER && !ftrace_filtered) {
1508 return t_hash_start(m, pos);
1509 iter->flags |= FTRACE_ITER_PRINTALL;
1513 if (iter->flags & FTRACE_ITER_HASH)
1514 return t_hash_start(m, pos);
1516 iter->pg = ftrace_pages_start;
1518 for (l = 0; l <= *pos; ) {
1519 p = t_next(m, p, &l);
1524 if (!p && iter->flags & FTRACE_ITER_FILTER)
1525 return t_hash_start(m, pos);
1530 static void t_stop(struct seq_file *m, void *p)
1532 mutex_unlock(&ftrace_lock);
1535 static int t_show(struct seq_file *m, void *v)
1537 struct ftrace_iterator *iter = m->private;
1538 struct dyn_ftrace *rec = v;
1539 char str[KSYM_SYMBOL_LEN];
1541 if (iter->flags & FTRACE_ITER_HASH)
1542 return t_hash_show(m, v);
1544 if (iter->flags & FTRACE_ITER_PRINTALL) {
1545 seq_printf(m, "#### all functions enabled ####\n");
1552 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1554 seq_printf(m, "%s\n", str);
1559 static struct seq_operations show_ftrace_seq_ops = {
1567 ftrace_avail_open(struct inode *inode, struct file *file)
1569 struct ftrace_iterator *iter;
1572 if (unlikely(ftrace_disabled))
1575 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1579 iter->pg = ftrace_pages_start;
1581 ret = seq_open(file, &show_ftrace_seq_ops);
1583 struct seq_file *m = file->private_data;
1593 int ftrace_avail_release(struct inode *inode, struct file *file)
1595 struct seq_file *m = (struct seq_file *)file->private_data;
1596 struct ftrace_iterator *iter = m->private;
1598 seq_release(inode, file);
1605 ftrace_failures_open(struct inode *inode, struct file *file)
1609 struct ftrace_iterator *iter;
1611 ret = ftrace_avail_open(inode, file);
1613 m = (struct seq_file *)file->private_data;
1614 iter = (struct ftrace_iterator *)m->private;
1615 iter->flags = FTRACE_ITER_FAILURES;
1622 static void ftrace_filter_reset(int enable)
1624 struct ftrace_page *pg;
1625 struct dyn_ftrace *rec;
1626 unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1628 mutex_lock(&ftrace_lock);
1630 ftrace_filtered = 0;
1631 do_for_each_ftrace_rec(pg, rec) {
1632 if (rec->flags & FTRACE_FL_FAILED)
1634 rec->flags &= ~type;
1635 } while_for_each_ftrace_rec();
1636 mutex_unlock(&ftrace_lock);
1640 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
1642 struct ftrace_iterator *iter;
1645 if (unlikely(ftrace_disabled))
1648 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1652 mutex_lock(&ftrace_regex_lock);
1653 if ((file->f_mode & FMODE_WRITE) &&
1654 !(file->f_flags & O_APPEND))
1655 ftrace_filter_reset(enable);
1657 if (file->f_mode & FMODE_READ) {
1658 iter->pg = ftrace_pages_start;
1659 iter->flags = enable ? FTRACE_ITER_FILTER :
1660 FTRACE_ITER_NOTRACE;
1662 ret = seq_open(file, &show_ftrace_seq_ops);
1664 struct seq_file *m = file->private_data;
1669 file->private_data = iter;
1670 mutex_unlock(&ftrace_regex_lock);
1676 ftrace_filter_open(struct inode *inode, struct file *file)
1678 return ftrace_regex_open(inode, file, 1);
1682 ftrace_notrace_open(struct inode *inode, struct file *file)
1684 return ftrace_regex_open(inode, file, 0);
1688 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1692 if (file->f_mode & FMODE_READ)
1693 ret = seq_lseek(file, offset, origin);
1695 file->f_pos = ret = 1;
1708 * (static function - no need for kernel doc)
1710 * Pass in a buffer containing a glob and this function will
1711 * set search to point to the search part of the buffer and
1712 * return the type of search it is (see enum above).
1713 * This does modify buff.
1715 * Returns enum type.
1716 * search returns the pointer to use for comparison.
1717 * not returns 1 if buff started with a '!'
1721 ftrace_setup_glob(char *buff, int len, char **search, int *not)
1723 int type = MATCH_FULL;
1726 if (buff[0] == '!') {
1735 for (i = 0; i < len; i++) {
1736 if (buff[i] == '*') {
1739 type = MATCH_END_ONLY;
1741 if (type == MATCH_END_ONLY)
1742 type = MATCH_MIDDLE_ONLY;
1744 type = MATCH_FRONT_ONLY;
1754 static int ftrace_match(char *str, char *regex, int len, int type)
1761 if (strcmp(str, regex) == 0)
1764 case MATCH_FRONT_ONLY:
1765 if (strncmp(str, regex, len) == 0)
1768 case MATCH_MIDDLE_ONLY:
1769 if (strstr(str, regex))
1772 case MATCH_END_ONLY:
1773 ptr = strstr(str, regex);
1774 if (ptr && (ptr[len] == 0))
1783 ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
1785 char str[KSYM_SYMBOL_LEN];
1787 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1788 return ftrace_match(str, regex, len, type);
1791 static void ftrace_match_records(char *buff, int len, int enable)
1793 unsigned int search_len;
1794 struct ftrace_page *pg;
1795 struct dyn_ftrace *rec;
1801 flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1802 type = ftrace_setup_glob(buff, len, &search, ¬);
1804 search_len = strlen(search);
1806 mutex_lock(&ftrace_lock);
1807 do_for_each_ftrace_rec(pg, rec) {
1809 if (rec->flags & FTRACE_FL_FAILED)
1812 if (ftrace_match_record(rec, search, search_len, type)) {
1814 rec->flags &= ~flag;
1819 * Only enable filtering if we have a function that
1822 if (enable && (rec->flags & FTRACE_FL_FILTER))
1823 ftrace_filtered = 1;
1824 } while_for_each_ftrace_rec();
1825 mutex_unlock(&ftrace_lock);
1829 ftrace_match_module_record(struct dyn_ftrace *rec, char *mod,
1830 char *regex, int len, int type)
1832 char str[KSYM_SYMBOL_LEN];
1835 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
1837 if (!modname || strcmp(modname, mod))
1840 /* blank search means to match all funcs in the mod */
1842 return ftrace_match(str, regex, len, type);
1847 static void ftrace_match_module_records(char *buff, char *mod, int enable)
1849 unsigned search_len = 0;
1850 struct ftrace_page *pg;
1851 struct dyn_ftrace *rec;
1852 int type = MATCH_FULL;
1853 char *search = buff;
1857 flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1859 /* blank or '*' mean the same */
1860 if (strcmp(buff, "*") == 0)
1863 /* handle the case of 'dont filter this module' */
1864 if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
1870 type = ftrace_setup_glob(buff, strlen(buff), &search, ¬);
1871 search_len = strlen(search);
1874 mutex_lock(&ftrace_lock);
1875 do_for_each_ftrace_rec(pg, rec) {
1877 if (rec->flags & FTRACE_FL_FAILED)
1880 if (ftrace_match_module_record(rec, mod,
1881 search, search_len, type)) {
1883 rec->flags &= ~flag;
1887 if (enable && (rec->flags & FTRACE_FL_FILTER))
1888 ftrace_filtered = 1;
1890 } while_for_each_ftrace_rec();
1891 mutex_unlock(&ftrace_lock);
1895 * We register the module command as a template to show others how
1896 * to register the a command as well.
1900 ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
1905 * cmd == 'mod' because we only registered this func
1906 * for the 'mod' ftrace_func_command.
1907 * But if you register one func with multiple commands,
1908 * you can tell which command was used by the cmd
1912 /* we must have a module name */
1916 mod = strsep(¶m, ":");
1920 ftrace_match_module_records(func, mod, enable);
1924 static struct ftrace_func_command ftrace_mod_cmd = {
1926 .func = ftrace_mod_callback,
1929 static int __init ftrace_mod_cmd_init(void)
1931 return register_ftrace_command(&ftrace_mod_cmd);
1933 device_initcall(ftrace_mod_cmd_init);
1936 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
1938 struct ftrace_func_probe *entry;
1939 struct hlist_head *hhd;
1940 struct hlist_node *n;
1944 key = hash_long(ip, FTRACE_HASH_BITS);
1946 hhd = &ftrace_func_hash[key];
1948 if (hlist_empty(hhd))
1952 * Disable preemption for these calls to prevent a RCU grace
1953 * period. This syncs the hash iteration and freeing of items
1954 * on the hash. rcu_read_lock is too dangerous here.
1956 resched = ftrace_preempt_disable();
1957 hlist_for_each_entry_rcu(entry, n, hhd, node) {
1958 if (entry->ip == ip)
1959 entry->ops->func(ip, parent_ip, &entry->data);
1961 ftrace_preempt_enable(resched);
1964 static struct ftrace_ops trace_probe_ops __read_mostly =
1966 .func = function_trace_probe_call,
1969 static int ftrace_probe_registered;
1971 static void __enable_ftrace_function_probe(void)
1975 if (ftrace_probe_registered)
1978 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1979 struct hlist_head *hhd = &ftrace_func_hash[i];
1983 /* Nothing registered? */
1984 if (i == FTRACE_FUNC_HASHSIZE)
1987 __register_ftrace_function(&trace_probe_ops);
1989 ftrace_probe_registered = 1;
1992 static void __disable_ftrace_function_probe(void)
1996 if (!ftrace_probe_registered)
1999 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2000 struct hlist_head *hhd = &ftrace_func_hash[i];
2005 /* no more funcs left */
2006 __unregister_ftrace_function(&trace_probe_ops);
2008 ftrace_probe_registered = 0;
2012 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
2014 struct ftrace_func_probe *entry =
2015 container_of(rhp, struct ftrace_func_probe, rcu);
2017 if (entry->ops->free)
2018 entry->ops->free(&entry->data);
2024 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2027 struct ftrace_func_probe *entry;
2028 struct ftrace_page *pg;
2029 struct dyn_ftrace *rec;
2035 type = ftrace_setup_glob(glob, strlen(glob), &search, ¬);
2036 len = strlen(search);
2038 /* we do not support '!' for function probes */
2042 mutex_lock(&ftrace_lock);
2043 do_for_each_ftrace_rec(pg, rec) {
2045 if (rec->flags & FTRACE_FL_FAILED)
2048 if (!ftrace_match_record(rec, search, len, type))
2051 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2053 /* If we did not process any, then return error */
2064 * The caller might want to do something special
2065 * for each function we find. We call the callback
2066 * to give the caller an opportunity to do so.
2068 if (ops->callback) {
2069 if (ops->callback(rec->ip, &entry->data) < 0) {
2070 /* caller does not like this func */
2077 entry->ip = rec->ip;
2079 key = hash_long(entry->ip, FTRACE_HASH_BITS);
2080 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
2082 } while_for_each_ftrace_rec();
2083 __enable_ftrace_function_probe();
2086 mutex_unlock(&ftrace_lock);
2092 PROBE_TEST_FUNC = 1,
2097 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2098 void *data, int flags)
2100 struct ftrace_func_probe *entry;
2101 struct hlist_node *n, *tmp;
2102 char str[KSYM_SYMBOL_LEN];
2103 int type = MATCH_FULL;
2107 if (glob && (strcmp(glob, "*") || !strlen(glob)))
2112 type = ftrace_setup_glob(glob, strlen(glob), &search, ¬);
2113 len = strlen(search);
2115 /* we do not support '!' for function probes */
2120 mutex_lock(&ftrace_lock);
2121 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2122 struct hlist_head *hhd = &ftrace_func_hash[i];
2124 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
2126 /* break up if statements for readability */
2127 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
2130 if ((flags & PROBE_TEST_DATA) && entry->data != data)
2133 /* do this last, since it is the most expensive */
2135 kallsyms_lookup(entry->ip, NULL, NULL,
2137 if (!ftrace_match(str, glob, len, type))
2141 hlist_del(&entry->node);
2142 call_rcu(&entry->rcu, ftrace_free_entry_rcu);
2145 __disable_ftrace_function_probe();
2146 mutex_unlock(&ftrace_lock);
2150 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2153 __unregister_ftrace_function_probe(glob, ops, data,
2154 PROBE_TEST_FUNC | PROBE_TEST_DATA);
2158 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
2160 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
2163 void unregister_ftrace_function_probe_all(char *glob)
2165 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
2168 static LIST_HEAD(ftrace_commands);
2169 static DEFINE_MUTEX(ftrace_cmd_mutex);
2171 int register_ftrace_command(struct ftrace_func_command *cmd)
2173 struct ftrace_func_command *p;
2176 mutex_lock(&ftrace_cmd_mutex);
2177 list_for_each_entry(p, &ftrace_commands, list) {
2178 if (strcmp(cmd->name, p->name) == 0) {
2183 list_add(&cmd->list, &ftrace_commands);
2185 mutex_unlock(&ftrace_cmd_mutex);
2190 int unregister_ftrace_command(struct ftrace_func_command *cmd)
2192 struct ftrace_func_command *p, *n;
2195 mutex_lock(&ftrace_cmd_mutex);
2196 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
2197 if (strcmp(cmd->name, p->name) == 0) {
2199 list_del_init(&p->list);
2204 mutex_unlock(&ftrace_cmd_mutex);
2209 static int ftrace_process_regex(char *buff, int len, int enable)
2211 char *func, *command, *next = buff;
2212 struct ftrace_func_command *p;
2215 func = strsep(&next, ":");
2218 ftrace_match_records(func, len, enable);
2224 command = strsep(&next, ":");
2226 mutex_lock(&ftrace_cmd_mutex);
2227 list_for_each_entry(p, &ftrace_commands, list) {
2228 if (strcmp(p->name, command) == 0) {
2229 ret = p->func(func, command, next, enable);
2234 mutex_unlock(&ftrace_cmd_mutex);
2240 ftrace_regex_write(struct file *file, const char __user *ubuf,
2241 size_t cnt, loff_t *ppos, int enable)
2243 struct ftrace_iterator *iter;
2248 if (!cnt || cnt < 0)
2251 mutex_lock(&ftrace_regex_lock);
2253 if (file->f_mode & FMODE_READ) {
2254 struct seq_file *m = file->private_data;
2257 iter = file->private_data;
2260 iter->flags &= ~FTRACE_ITER_CONT;
2261 iter->buffer_idx = 0;
2264 ret = get_user(ch, ubuf++);
2270 if (!(iter->flags & ~FTRACE_ITER_CONT)) {
2271 /* skip white space */
2272 while (cnt && isspace(ch)) {
2273 ret = get_user(ch, ubuf++);
2281 file->f_pos += read;
2286 iter->buffer_idx = 0;
2289 while (cnt && !isspace(ch)) {
2290 if (iter->buffer_idx < FTRACE_BUFF_MAX)
2291 iter->buffer[iter->buffer_idx++] = ch;
2296 ret = get_user(ch, ubuf++);
2305 iter->buffer[iter->buffer_idx] = 0;
2306 ret = ftrace_process_regex(iter->buffer,
2307 iter->buffer_idx, enable);
2310 iter->buffer_idx = 0;
2312 iter->flags |= FTRACE_ITER_CONT;
2315 file->f_pos += read;
2319 mutex_unlock(&ftrace_regex_lock);
2325 ftrace_filter_write(struct file *file, const char __user *ubuf,
2326 size_t cnt, loff_t *ppos)
2328 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
2332 ftrace_notrace_write(struct file *file, const char __user *ubuf,
2333 size_t cnt, loff_t *ppos)
2335 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
2339 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
2341 if (unlikely(ftrace_disabled))
2344 mutex_lock(&ftrace_regex_lock);
2346 ftrace_filter_reset(enable);
2348 ftrace_match_records(buf, len, enable);
2349 mutex_unlock(&ftrace_regex_lock);
2353 * ftrace_set_filter - set a function to filter on in ftrace
2354 * @buf - the string that holds the function filter text.
2355 * @len - the length of the string.
2356 * @reset - non zero to reset all filters before applying this filter.
2358 * Filters denote which functions should be enabled when tracing is enabled.
2359 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2361 void ftrace_set_filter(unsigned char *buf, int len, int reset)
2363 ftrace_set_regex(buf, len, reset, 1);
2367 * ftrace_set_notrace - set a function to not trace in ftrace
2368 * @buf - the string that holds the function notrace text.
2369 * @len - the length of the string.
2370 * @reset - non zero to reset all filters before applying this filter.
2372 * Notrace Filters denote which functions should not be enabled when tracing
2373 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2376 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
2378 ftrace_set_regex(buf, len, reset, 0);
2382 * command line interface to allow users to set filters on boot up.
2384 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
2385 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
2386 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
2388 static int __init set_ftrace_notrace(char *str)
2390 strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
2393 __setup("ftrace_notrace=", set_ftrace_notrace);
2395 static int __init set_ftrace_filter(char *str)
2397 strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
2400 __setup("ftrace_filter=", set_ftrace_filter);
2402 static void __init set_ftrace_early_filter(char *buf, int enable)
2407 func = strsep(&buf, ",");
2408 ftrace_set_regex(func, strlen(func), 0, enable);
2412 static void __init set_ftrace_early_filters(void)
2414 if (ftrace_filter_buf[0])
2415 set_ftrace_early_filter(ftrace_filter_buf, 1);
2416 if (ftrace_notrace_buf[0])
2417 set_ftrace_early_filter(ftrace_notrace_buf, 0);
2421 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
2423 struct seq_file *m = (struct seq_file *)file->private_data;
2424 struct ftrace_iterator *iter;
2426 mutex_lock(&ftrace_regex_lock);
2427 if (file->f_mode & FMODE_READ) {
2430 seq_release(inode, file);
2432 iter = file->private_data;
2434 if (iter->buffer_idx) {
2436 iter->buffer[iter->buffer_idx] = 0;
2437 ftrace_match_records(iter->buffer, iter->buffer_idx, enable);
2440 mutex_lock(&ftrace_lock);
2441 if (ftrace_start_up && ftrace_enabled)
2442 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
2443 mutex_unlock(&ftrace_lock);
2446 mutex_unlock(&ftrace_regex_lock);
2451 ftrace_filter_release(struct inode *inode, struct file *file)
2453 return ftrace_regex_release(inode, file, 1);
2457 ftrace_notrace_release(struct inode *inode, struct file *file)
2459 return ftrace_regex_release(inode, file, 0);
2462 static const struct file_operations ftrace_avail_fops = {
2463 .open = ftrace_avail_open,
2465 .llseek = seq_lseek,
2466 .release = ftrace_avail_release,
2469 static const struct file_operations ftrace_failures_fops = {
2470 .open = ftrace_failures_open,
2472 .llseek = seq_lseek,
2473 .release = ftrace_avail_release,
2476 static const struct file_operations ftrace_filter_fops = {
2477 .open = ftrace_filter_open,
2479 .write = ftrace_filter_write,
2480 .llseek = ftrace_regex_lseek,
2481 .release = ftrace_filter_release,
2484 static const struct file_operations ftrace_notrace_fops = {
2485 .open = ftrace_notrace_open,
2487 .write = ftrace_notrace_write,
2488 .llseek = ftrace_regex_lseek,
2489 .release = ftrace_notrace_release,
2492 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2494 static DEFINE_MUTEX(graph_lock);
2496 int ftrace_graph_count;
2497 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
2500 __g_next(struct seq_file *m, loff_t *pos)
2502 unsigned long *array = m->private;
2504 if (*pos >= ftrace_graph_count)
2506 return &array[*pos];
2510 g_next(struct seq_file *m, void *v, loff_t *pos)
2513 return __g_next(m, pos);
2516 static void *g_start(struct seq_file *m, loff_t *pos)
2518 mutex_lock(&graph_lock);
2520 /* Nothing, tell g_show to print all functions are enabled */
2521 if (!ftrace_graph_count && !*pos)
2524 return __g_next(m, pos);
2527 static void g_stop(struct seq_file *m, void *p)
2529 mutex_unlock(&graph_lock);
2532 static int g_show(struct seq_file *m, void *v)
2534 unsigned long *ptr = v;
2535 char str[KSYM_SYMBOL_LEN];
2540 if (ptr == (unsigned long *)1) {
2541 seq_printf(m, "#### all functions enabled ####\n");
2545 kallsyms_lookup(*ptr, NULL, NULL, NULL, str);
2547 seq_printf(m, "%s\n", str);
2552 static struct seq_operations ftrace_graph_seq_ops = {
2560 ftrace_graph_open(struct inode *inode, struct file *file)
2564 if (unlikely(ftrace_disabled))
2567 mutex_lock(&graph_lock);
2568 if ((file->f_mode & FMODE_WRITE) &&
2569 !(file->f_flags & O_APPEND)) {
2570 ftrace_graph_count = 0;
2571 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
2574 if (file->f_mode & FMODE_READ) {
2575 ret = seq_open(file, &ftrace_graph_seq_ops);
2577 struct seq_file *m = file->private_data;
2578 m->private = ftrace_graph_funcs;
2581 file->private_data = ftrace_graph_funcs;
2582 mutex_unlock(&graph_lock);
2588 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
2590 struct dyn_ftrace *rec;
2591 struct ftrace_page *pg;
2599 if (ftrace_disabled)
2603 type = ftrace_setup_glob(buffer, strlen(buffer), &search, ¬);
2607 search_len = strlen(search);
2609 mutex_lock(&ftrace_lock);
2610 do_for_each_ftrace_rec(pg, rec) {
2612 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
2615 if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
2618 if (ftrace_match_record(rec, search, search_len, type)) {
2619 /* ensure it is not already in the array */
2621 for (i = 0; i < *idx; i++)
2622 if (array[i] == rec->ip) {
2627 array[(*idx)++] = rec->ip;
2631 } while_for_each_ftrace_rec();
2633 mutex_unlock(&ftrace_lock);
2635 return found ? 0 : -EINVAL;
2639 ftrace_graph_write(struct file *file, const char __user *ubuf,
2640 size_t cnt, loff_t *ppos)
2642 unsigned char buffer[FTRACE_BUFF_MAX+1];
2643 unsigned long *array;
2649 if (!cnt || cnt < 0)
2652 mutex_lock(&graph_lock);
2654 if (ftrace_graph_count >= FTRACE_GRAPH_MAX_FUNCS) {
2659 if (file->f_mode & FMODE_READ) {
2660 struct seq_file *m = file->private_data;
2663 array = file->private_data;
2665 ret = get_user(ch, ubuf++);
2671 /* skip white space */
2672 while (cnt && isspace(ch)) {
2673 ret = get_user(ch, ubuf++);
2686 while (cnt && !isspace(ch)) {
2687 if (index < FTRACE_BUFF_MAX)
2688 buffer[index++] = ch;
2693 ret = get_user(ch, ubuf++);
2701 /* we allow only one expression at a time */
2702 ret = ftrace_set_func(array, &ftrace_graph_count, buffer);
2706 file->f_pos += read;
2710 mutex_unlock(&graph_lock);
2715 static const struct file_operations ftrace_graph_fops = {
2716 .open = ftrace_graph_open,
2718 .write = ftrace_graph_write,
2720 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2722 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
2725 trace_create_file("available_filter_functions", 0444,
2726 d_tracer, NULL, &ftrace_avail_fops);
2728 trace_create_file("failures", 0444,
2729 d_tracer, NULL, &ftrace_failures_fops);
2731 trace_create_file("set_ftrace_filter", 0644, d_tracer,
2732 NULL, &ftrace_filter_fops);
2734 trace_create_file("set_ftrace_notrace", 0644, d_tracer,
2735 NULL, &ftrace_notrace_fops);
2737 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2738 trace_create_file("set_graph_function", 0444, d_tracer,
2740 &ftrace_graph_fops);
2741 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2746 static int ftrace_convert_nops(struct module *mod,
2747 unsigned long *start,
2752 unsigned long flags;
2754 mutex_lock(&ftrace_lock);
2757 addr = ftrace_call_adjust(*p++);
2759 * Some architecture linkers will pad between
2760 * the different mcount_loc sections of different
2761 * object files to satisfy alignments.
2762 * Skip any NULL pointers.
2766 ftrace_record_ip(addr);
2769 /* disable interrupts to prevent kstop machine */
2770 local_irq_save(flags);
2771 ftrace_update_code(mod);
2772 local_irq_restore(flags);
2773 mutex_unlock(&ftrace_lock);
2778 #ifdef CONFIG_MODULES
2779 void ftrace_release(void *start, void *end)
2781 struct dyn_ftrace *rec;
2782 struct ftrace_page *pg;
2783 unsigned long s = (unsigned long)start;
2784 unsigned long e = (unsigned long)end;
2786 if (ftrace_disabled || !start || start == end)
2789 mutex_lock(&ftrace_lock);
2790 do_for_each_ftrace_rec(pg, rec) {
2791 if ((rec->ip >= s) && (rec->ip < e)) {
2793 * rec->ip is changed in ftrace_free_rec()
2794 * It should not between s and e if record was freed.
2796 FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE);
2797 ftrace_free_rec(rec);
2799 } while_for_each_ftrace_rec();
2800 mutex_unlock(&ftrace_lock);
2803 static void ftrace_init_module(struct module *mod,
2804 unsigned long *start, unsigned long *end)
2806 if (ftrace_disabled || start == end)
2808 ftrace_convert_nops(mod, start, end);
2811 static int ftrace_module_notify(struct notifier_block *self,
2812 unsigned long val, void *data)
2814 struct module *mod = data;
2817 case MODULE_STATE_COMING:
2818 ftrace_init_module(mod, mod->ftrace_callsites,
2819 mod->ftrace_callsites +
2820 mod->num_ftrace_callsites);
2822 case MODULE_STATE_GOING:
2823 ftrace_release(mod->ftrace_callsites,
2824 mod->ftrace_callsites +
2825 mod->num_ftrace_callsites);
2832 static int ftrace_module_notify(struct notifier_block *self,
2833 unsigned long val, void *data)
2837 #endif /* CONFIG_MODULES */
2839 struct notifier_block ftrace_module_nb = {
2840 .notifier_call = ftrace_module_notify,
2844 extern unsigned long __start_mcount_loc[];
2845 extern unsigned long __stop_mcount_loc[];
2847 void __init ftrace_init(void)
2849 unsigned long count, addr, flags;
2852 /* Keep the ftrace pointer to the stub */
2853 addr = (unsigned long)ftrace_stub;
2855 local_irq_save(flags);
2856 ftrace_dyn_arch_init(&addr);
2857 local_irq_restore(flags);
2859 /* ftrace_dyn_arch_init places the return code in addr */
2863 count = __stop_mcount_loc - __start_mcount_loc;
2865 ret = ftrace_dyn_table_alloc(count);
2869 last_ftrace_enabled = ftrace_enabled = 1;
2871 ret = ftrace_convert_nops(NULL,
2875 ret = register_module_notifier(&ftrace_module_nb);
2877 pr_warning("Failed to register trace ftrace module notifier\n");
2879 set_ftrace_early_filters();
2883 ftrace_disabled = 1;
2888 static int __init ftrace_nodyn_init(void)
2893 device_initcall(ftrace_nodyn_init);
2895 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
2896 static inline void ftrace_startup_enable(int command) { }
2897 /* Keep as macros so we do not need to define the commands */
2898 # define ftrace_startup(command) do { } while (0)
2899 # define ftrace_shutdown(command) do { } while (0)
2900 # define ftrace_startup_sysctl() do { } while (0)
2901 # define ftrace_shutdown_sysctl() do { } while (0)
2902 #endif /* CONFIG_DYNAMIC_FTRACE */
2905 ftrace_pid_read(struct file *file, char __user *ubuf,
2906 size_t cnt, loff_t *ppos)
2911 if (ftrace_pid_trace == ftrace_swapper_pid)
2912 r = sprintf(buf, "swapper tasks\n");
2913 else if (ftrace_pid_trace)
2914 r = sprintf(buf, "%u\n", pid_vnr(ftrace_pid_trace));
2916 r = sprintf(buf, "no pid\n");
2918 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2921 static void clear_ftrace_swapper(void)
2923 struct task_struct *p;
2927 for_each_online_cpu(cpu) {
2929 clear_tsk_trace_trace(p);
2934 static void set_ftrace_swapper(void)
2936 struct task_struct *p;
2940 for_each_online_cpu(cpu) {
2942 set_tsk_trace_trace(p);
2947 static void clear_ftrace_pid(struct pid *pid)
2949 struct task_struct *p;
2952 do_each_pid_task(pid, PIDTYPE_PID, p) {
2953 clear_tsk_trace_trace(p);
2954 } while_each_pid_task(pid, PIDTYPE_PID, p);
2960 static void set_ftrace_pid(struct pid *pid)
2962 struct task_struct *p;
2965 do_each_pid_task(pid, PIDTYPE_PID, p) {
2966 set_tsk_trace_trace(p);
2967 } while_each_pid_task(pid, PIDTYPE_PID, p);
2971 static void clear_ftrace_pid_task(struct pid **pid)
2973 if (*pid == ftrace_swapper_pid)
2974 clear_ftrace_swapper();
2976 clear_ftrace_pid(*pid);
2981 static void set_ftrace_pid_task(struct pid *pid)
2983 if (pid == ftrace_swapper_pid)
2984 set_ftrace_swapper();
2986 set_ftrace_pid(pid);
2990 ftrace_pid_write(struct file *filp, const char __user *ubuf,
2991 size_t cnt, loff_t *ppos)
2998 if (cnt >= sizeof(buf))
3001 if (copy_from_user(&buf, ubuf, cnt))
3006 ret = strict_strtol(buf, 10, &val);
3010 mutex_lock(&ftrace_lock);
3012 /* disable pid tracing */
3013 if (!ftrace_pid_trace)
3016 clear_ftrace_pid_task(&ftrace_pid_trace);
3019 /* swapper task is special */
3021 pid = ftrace_swapper_pid;
3022 if (pid == ftrace_pid_trace)
3025 pid = find_get_pid(val);
3027 if (pid == ftrace_pid_trace) {
3033 if (ftrace_pid_trace)
3034 clear_ftrace_pid_task(&ftrace_pid_trace);
3039 ftrace_pid_trace = pid;
3041 set_ftrace_pid_task(ftrace_pid_trace);
3044 /* update the function call */
3045 ftrace_update_pid_func();
3046 ftrace_startup_enable(0);
3049 mutex_unlock(&ftrace_lock);
3054 static const struct file_operations ftrace_pid_fops = {
3055 .read = ftrace_pid_read,
3056 .write = ftrace_pid_write,
3059 static __init int ftrace_init_debugfs(void)
3061 struct dentry *d_tracer;
3063 d_tracer = tracing_init_dentry();
3067 ftrace_init_dyn_debugfs(d_tracer);
3069 trace_create_file("set_ftrace_pid", 0644, d_tracer,
3070 NULL, &ftrace_pid_fops);
3072 ftrace_profile_debugfs(d_tracer);
3076 fs_initcall(ftrace_init_debugfs);
3079 * ftrace_kill - kill ftrace
3081 * This function should be used by panic code. It stops ftrace
3082 * but in a not so nice way. If you need to simply kill ftrace
3083 * from a non-atomic section, use ftrace_kill.
3085 void ftrace_kill(void)
3087 ftrace_disabled = 1;
3089 clear_ftrace_function();
3093 * register_ftrace_function - register a function for profiling
3094 * @ops - ops structure that holds the function for profiling.
3096 * Register a function to be called by all functions in the
3099 * Note: @ops->func and all the functions it calls must be labeled
3100 * with "notrace", otherwise it will go into a
3103 int register_ftrace_function(struct ftrace_ops *ops)
3107 if (unlikely(ftrace_disabled))
3110 mutex_lock(&ftrace_lock);
3112 ret = __register_ftrace_function(ops);
3115 mutex_unlock(&ftrace_lock);
3120 * unregister_ftrace_function - unregister a function for profiling.
3121 * @ops - ops structure that holds the function to unregister
3123 * Unregister a function that was added to be called by ftrace profiling.
3125 int unregister_ftrace_function(struct ftrace_ops *ops)
3129 mutex_lock(&ftrace_lock);
3130 ret = __unregister_ftrace_function(ops);
3132 mutex_unlock(&ftrace_lock);
3138 ftrace_enable_sysctl(struct ctl_table *table, int write,
3139 struct file *file, void __user *buffer, size_t *lenp,
3144 if (unlikely(ftrace_disabled))
3147 mutex_lock(&ftrace_lock);
3149 ret = proc_dointvec(table, write, file, buffer, lenp, ppos);
3151 if (ret || !write || (last_ftrace_enabled == ftrace_enabled))
3154 last_ftrace_enabled = ftrace_enabled;
3156 if (ftrace_enabled) {
3158 ftrace_startup_sysctl();
3160 /* we are starting ftrace again */
3161 if (ftrace_list != &ftrace_list_end) {
3162 if (ftrace_list->next == &ftrace_list_end)
3163 ftrace_trace_function = ftrace_list->func;
3165 ftrace_trace_function = ftrace_list_func;
3169 /* stopping ftrace calls (just send to ftrace_stub) */
3170 ftrace_trace_function = ftrace_stub;
3172 ftrace_shutdown_sysctl();
3176 mutex_unlock(&ftrace_lock);
3180 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3182 static int ftrace_graph_active;
3183 static struct notifier_block ftrace_suspend_notifier;
3185 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
3190 /* The callbacks that hook a function */
3191 trace_func_graph_ret_t ftrace_graph_return =
3192 (trace_func_graph_ret_t)ftrace_stub;
3193 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
3195 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
3196 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
3200 unsigned long flags;
3201 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
3202 struct task_struct *g, *t;
3204 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
3205 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
3206 * sizeof(struct ftrace_ret_stack),
3208 if (!ret_stack_list[i]) {
3216 read_lock_irqsave(&tasklist_lock, flags);
3217 do_each_thread(g, t) {
3223 if (t->ret_stack == NULL) {
3224 atomic_set(&t->tracing_graph_pause, 0);
3225 atomic_set(&t->trace_overrun, 0);
3226 t->curr_ret_stack = -1;
3227 /* Make sure the tasks see the -1 first: */
3229 t->ret_stack = ret_stack_list[start++];
3231 } while_each_thread(g, t);
3234 read_unlock_irqrestore(&tasklist_lock, flags);
3236 for (i = start; i < end; i++)
3237 kfree(ret_stack_list[i]);
3242 ftrace_graph_probe_sched_switch(struct rq *__rq, struct task_struct *prev,
3243 struct task_struct *next)
3245 unsigned long long timestamp;
3249 * Does the user want to count the time a function was asleep.
3250 * If so, do not update the time stamps.
3252 if (trace_flags & TRACE_ITER_SLEEP_TIME)
3255 timestamp = trace_clock_local();
3257 prev->ftrace_timestamp = timestamp;
3259 /* only process tasks that we timestamped */
3260 if (!next->ftrace_timestamp)
3264 * Update all the counters in next to make up for the
3265 * time next was sleeping.
3267 timestamp -= next->ftrace_timestamp;
3269 for (index = next->curr_ret_stack; index >= 0; index--)
3270 next->ret_stack[index].calltime += timestamp;
3273 /* Allocate a return stack for each task */
3274 static int start_graph_tracing(void)
3276 struct ftrace_ret_stack **ret_stack_list;
3279 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
3280 sizeof(struct ftrace_ret_stack *),
3283 if (!ret_stack_list)
3286 /* The cpu_boot init_task->ret_stack will never be freed */
3287 for_each_online_cpu(cpu) {
3288 if (!idle_task(cpu)->ret_stack)
3289 ftrace_graph_init_task(idle_task(cpu));
3293 ret = alloc_retstack_tasklist(ret_stack_list);
3294 } while (ret == -EAGAIN);
3297 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch);
3299 pr_info("ftrace_graph: Couldn't activate tracepoint"
3300 " probe to kernel_sched_switch\n");
3303 kfree(ret_stack_list);
3308 * Hibernation protection.
3309 * The state of the current task is too much unstable during
3310 * suspend/restore to disk. We want to protect against that.
3313 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
3317 case PM_HIBERNATION_PREPARE:
3318 pause_graph_tracing();
3321 case PM_POST_HIBERNATION:
3322 unpause_graph_tracing();
3328 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
3329 trace_func_graph_ent_t entryfunc)
3333 mutex_lock(&ftrace_lock);
3335 /* we currently allow only one tracer registered at a time */
3336 if (ftrace_graph_active) {
3341 ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
3342 register_pm_notifier(&ftrace_suspend_notifier);
3344 ftrace_graph_active++;
3345 ret = start_graph_tracing();
3347 ftrace_graph_active--;
3351 ftrace_graph_return = retfunc;
3352 ftrace_graph_entry = entryfunc;
3354 ftrace_startup(FTRACE_START_FUNC_RET);
3357 mutex_unlock(&ftrace_lock);
3361 void unregister_ftrace_graph(void)
3363 mutex_lock(&ftrace_lock);
3365 if (unlikely(!ftrace_graph_active))
3368 ftrace_graph_active--;
3369 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch);
3370 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
3371 ftrace_graph_entry = ftrace_graph_entry_stub;
3372 ftrace_shutdown(FTRACE_STOP_FUNC_RET);
3373 unregister_pm_notifier(&ftrace_suspend_notifier);
3376 mutex_unlock(&ftrace_lock);
3379 /* Allocate a return stack for newly created task */
3380 void ftrace_graph_init_task(struct task_struct *t)
3382 /* Make sure we do not use the parent ret_stack */
3383 t->ret_stack = NULL;
3385 if (ftrace_graph_active) {
3386 struct ftrace_ret_stack *ret_stack;
3388 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
3389 * sizeof(struct ftrace_ret_stack),
3393 t->curr_ret_stack = -1;
3394 atomic_set(&t->tracing_graph_pause, 0);
3395 atomic_set(&t->trace_overrun, 0);
3396 t->ftrace_timestamp = 0;
3397 /* make curr_ret_stack visable before we add the ret_stack */
3399 t->ret_stack = ret_stack;
3403 void ftrace_graph_exit_task(struct task_struct *t)
3405 struct ftrace_ret_stack *ret_stack = t->ret_stack;
3407 t->ret_stack = NULL;
3408 /* NULL must become visible to IRQs before we free it: */
3414 void ftrace_graph_stop(void)