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/debugfs.h>
21 #include <linux/hardirq.h>
22 #include <linux/kthread.h>
23 #include <linux/uaccess.h>
24 #include <linux/ftrace.h>
25 #include <linux/sysctl.h>
26 #include <linux/ctype.h>
27 #include <linux/hash.h>
28 #include <linux/list.h>
32 /* ftrace_enabled is a method to turn ftrace on or off */
33 int ftrace_enabled __read_mostly;
34 static int last_ftrace_enabled;
37 * ftrace_disabled is set when an anomaly is discovered.
38 * ftrace_disabled is much stronger than ftrace_enabled.
40 static int ftrace_disabled __read_mostly;
42 static DEFINE_SPINLOCK(ftrace_lock);
43 static DEFINE_MUTEX(ftrace_sysctl_lock);
45 static struct ftrace_ops ftrace_list_end __read_mostly =
50 static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
51 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
53 void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
55 struct ftrace_ops *op = ftrace_list;
57 /* in case someone actually ports this to alpha! */
58 read_barrier_depends();
60 while (op != &ftrace_list_end) {
62 read_barrier_depends();
63 op->func(ip, parent_ip);
69 * clear_ftrace_function - reset the ftrace function
71 * This NULLs the ftrace function and in essence stops
72 * tracing. There may be lag
74 void clear_ftrace_function(void)
76 ftrace_trace_function = ftrace_stub;
79 static int __register_ftrace_function(struct ftrace_ops *ops)
81 /* Should never be called by interrupts */
82 spin_lock(&ftrace_lock);
84 ops->next = ftrace_list;
86 * We are entering ops into the ftrace_list but another
87 * CPU might be walking that list. We need to make sure
88 * the ops->next pointer is valid before another CPU sees
89 * the ops pointer included into the ftrace_list.
96 * For one func, simply call it directly.
97 * For more than one func, call the chain.
99 if (ops->next == &ftrace_list_end)
100 ftrace_trace_function = ops->func;
102 ftrace_trace_function = ftrace_list_func;
105 spin_unlock(&ftrace_lock);
110 static int __unregister_ftrace_function(struct ftrace_ops *ops)
112 struct ftrace_ops **p;
115 spin_lock(&ftrace_lock);
118 * If we are removing the last function, then simply point
119 * to the ftrace_stub.
121 if (ftrace_list == ops && ops->next == &ftrace_list_end) {
122 ftrace_trace_function = ftrace_stub;
123 ftrace_list = &ftrace_list_end;
127 for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
138 if (ftrace_enabled) {
139 /* If we only have one func left, then call that directly */
140 if (ftrace_list == &ftrace_list_end ||
141 ftrace_list->next == &ftrace_list_end)
142 ftrace_trace_function = ftrace_list->func;
146 spin_unlock(&ftrace_lock);
151 #ifdef CONFIG_DYNAMIC_FTRACE
153 static struct task_struct *ftraced_task;
156 FTRACE_ENABLE_CALLS = (1 << 0),
157 FTRACE_DISABLE_CALLS = (1 << 1),
158 FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
159 FTRACE_ENABLE_MCOUNT = (1 << 3),
160 FTRACE_DISABLE_MCOUNT = (1 << 4),
163 static int ftrace_filtered;
165 static struct hlist_head ftrace_hash[FTRACE_HASHSIZE];
167 static DEFINE_PER_CPU(int, ftrace_shutdown_disable_cpu);
169 static DEFINE_SPINLOCK(ftrace_shutdown_lock);
170 static DEFINE_MUTEX(ftraced_lock);
171 static DEFINE_MUTEX(ftrace_regex_lock);
174 struct ftrace_page *next;
176 struct dyn_ftrace records[];
179 #define ENTRIES_PER_PAGE \
180 ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
182 /* estimate from running different kernels */
183 #define NR_TO_INIT 10000
185 static struct ftrace_page *ftrace_pages_start;
186 static struct ftrace_page *ftrace_pages;
188 static int ftraced_trigger;
189 static int ftraced_suspend;
190 static int ftraced_stop;
192 static int ftrace_record_suspend;
194 static struct dyn_ftrace *ftrace_free_records;
197 ftrace_ip_in_hash(unsigned long ip, unsigned long key)
199 struct dyn_ftrace *p;
200 struct hlist_node *t;
203 hlist_for_each_entry_rcu(p, t, &ftrace_hash[key], node) {
214 ftrace_add_hash(struct dyn_ftrace *node, unsigned long key)
216 hlist_add_head_rcu(&node->node, &ftrace_hash[key]);
219 /* called from kstop_machine */
220 static inline void ftrace_del_hash(struct dyn_ftrace *node)
222 hlist_del(&node->node);
225 static void ftrace_free_rec(struct dyn_ftrace *rec)
227 /* no locking, only called from kstop_machine */
229 rec->ip = (unsigned long)ftrace_free_records;
230 ftrace_free_records = rec;
231 rec->flags |= FTRACE_FL_FREE;
234 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
236 struct dyn_ftrace *rec;
238 /* First check for freed records */
239 if (ftrace_free_records) {
240 rec = ftrace_free_records;
242 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
244 ftrace_free_records = NULL;
250 ftrace_free_records = (void *)rec->ip;
251 memset(rec, 0, sizeof(*rec));
255 if (ftrace_pages->index == ENTRIES_PER_PAGE) {
256 if (!ftrace_pages->next)
258 ftrace_pages = ftrace_pages->next;
261 return &ftrace_pages->records[ftrace_pages->index++];
265 ftrace_record_ip(unsigned long ip)
267 struct dyn_ftrace *node;
274 if (!ftrace_enabled || ftrace_disabled)
277 resched = need_resched();
278 preempt_disable_notrace();
281 * We simply need to protect against recursion.
282 * Use the the raw version of smp_processor_id and not
283 * __get_cpu_var which can call debug hooks that can
284 * cause a recursive crash here.
286 cpu = raw_smp_processor_id();
287 per_cpu(ftrace_shutdown_disable_cpu, cpu)++;
288 if (per_cpu(ftrace_shutdown_disable_cpu, cpu) != 1)
291 if (unlikely(ftrace_record_suspend))
294 key = hash_long(ip, FTRACE_HASHBITS);
296 WARN_ON_ONCE(key >= FTRACE_HASHSIZE);
298 if (ftrace_ip_in_hash(ip, key))
301 atomic = irqs_disabled();
303 spin_lock_irqsave(&ftrace_shutdown_lock, flags);
305 /* This ip may have hit the hash before the lock */
306 if (ftrace_ip_in_hash(ip, key))
310 * There's a slight race that the ftraced will update the
311 * hash and reset here. If it is already converted, skip it.
313 if (ftrace_ip_converted(ip))
316 node = ftrace_alloc_dyn_node(ip);
322 ftrace_add_hash(node, key);
327 spin_unlock_irqrestore(&ftrace_shutdown_lock, flags);
329 per_cpu(ftrace_shutdown_disable_cpu, cpu)--;
331 /* prevent recursion with scheduler */
333 preempt_enable_no_resched_notrace();
335 preempt_enable_notrace();
338 #define FTRACE_ADDR ((long)(ftrace_caller))
339 #define MCOUNT_ADDR ((long)(mcount))
342 __ftrace_replace_code(struct dyn_ftrace *rec,
343 unsigned char *old, unsigned char *new, int enable)
345 unsigned long ip, fl;
349 if (ftrace_filtered && enable) {
351 * If filtering is on:
353 * If this record is set to be filtered and
354 * is enabled then do nothing.
356 * If this record is set to be filtered and
357 * it is not enabled, enable it.
359 * If this record is not set to be filtered
360 * and it is not enabled do nothing.
362 * If this record is set not to trace then
365 * If this record is not set to be filtered and
366 * it is enabled, disable it.
368 fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED);
370 if ((fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED)) ||
371 (fl == 0) || (rec->flags & FTRACE_FL_NOTRACE))
375 * If it is enabled disable it,
376 * otherwise enable it!
378 if (fl == FTRACE_FL_ENABLED) {
379 /* swap new and old */
381 old = ftrace_call_replace(ip, FTRACE_ADDR);
382 rec->flags &= ~FTRACE_FL_ENABLED;
384 new = ftrace_call_replace(ip, FTRACE_ADDR);
385 rec->flags |= FTRACE_FL_ENABLED;
391 * If this record is set not to trace and is
392 * not enabled, do nothing.
394 fl = rec->flags & (FTRACE_FL_NOTRACE | FTRACE_FL_ENABLED);
395 if (fl == FTRACE_FL_NOTRACE)
398 new = ftrace_call_replace(ip, FTRACE_ADDR);
400 old = ftrace_call_replace(ip, FTRACE_ADDR);
403 if (rec->flags & FTRACE_FL_ENABLED)
405 rec->flags |= FTRACE_FL_ENABLED;
407 if (!(rec->flags & FTRACE_FL_ENABLED))
409 rec->flags &= ~FTRACE_FL_ENABLED;
413 return ftrace_modify_code(ip, old, new);
416 static void ftrace_replace_code(int enable)
419 unsigned char *new = NULL, *old = NULL;
420 struct dyn_ftrace *rec;
421 struct ftrace_page *pg;
424 old = ftrace_nop_replace();
426 new = ftrace_nop_replace();
428 for (pg = ftrace_pages_start; pg; pg = pg->next) {
429 for (i = 0; i < pg->index; i++) {
430 rec = &pg->records[i];
432 /* don't modify code that has already faulted */
433 if (rec->flags & FTRACE_FL_FAILED)
436 failed = __ftrace_replace_code(rec, old, new, enable);
437 if (failed && (rec->flags & FTRACE_FL_CONVERTED)) {
438 rec->flags |= FTRACE_FL_FAILED;
439 if ((system_state == SYSTEM_BOOTING) ||
440 !kernel_text_address(rec->ip)) {
441 ftrace_del_hash(rec);
442 ftrace_free_rec(rec);
449 static void ftrace_shutdown_replenish(void)
451 if (ftrace_pages->next)
454 /* allocate another page */
455 ftrace_pages->next = (void *)get_zeroed_page(GFP_KERNEL);
459 ftrace_code_disable(struct dyn_ftrace *rec)
462 unsigned char *nop, *call;
467 nop = ftrace_nop_replace();
468 call = ftrace_call_replace(ip, MCOUNT_ADDR);
470 failed = ftrace_modify_code(ip, call, nop);
472 rec->flags |= FTRACE_FL_FAILED;
478 static int __ftrace_update_code(void *ignore);
480 static int __ftrace_modify_code(void *data)
485 if (*command & FTRACE_ENABLE_CALLS) {
487 * Update any recorded ips now that we have the
490 __ftrace_update_code(NULL);
491 ftrace_replace_code(1);
492 } else if (*command & FTRACE_DISABLE_CALLS)
493 ftrace_replace_code(0);
495 if (*command & FTRACE_UPDATE_TRACE_FUNC)
496 ftrace_update_ftrace_func(ftrace_trace_function);
498 if (*command & FTRACE_ENABLE_MCOUNT) {
499 addr = (unsigned long)ftrace_record_ip;
500 ftrace_mcount_set(&addr);
501 } else if (*command & FTRACE_DISABLE_MCOUNT) {
502 addr = (unsigned long)ftrace_stub;
503 ftrace_mcount_set(&addr);
509 static void ftrace_run_update_code(int command)
511 stop_machine_run(__ftrace_modify_code, &command, NR_CPUS);
514 void ftrace_disable_daemon(void)
516 /* Stop the daemon from calling kstop_machine */
517 mutex_lock(&ftraced_lock);
519 mutex_unlock(&ftraced_lock);
521 ftrace_force_update();
524 void ftrace_enable_daemon(void)
526 mutex_lock(&ftraced_lock);
528 mutex_unlock(&ftraced_lock);
530 ftrace_force_update();
533 static ftrace_func_t saved_ftrace_func;
535 static void ftrace_startup(void)
539 if (unlikely(ftrace_disabled))
542 mutex_lock(&ftraced_lock);
544 if (ftraced_suspend == 1)
545 command |= FTRACE_ENABLE_CALLS;
547 if (saved_ftrace_func != ftrace_trace_function) {
548 saved_ftrace_func = ftrace_trace_function;
549 command |= FTRACE_UPDATE_TRACE_FUNC;
552 if (!command || !ftrace_enabled)
555 ftrace_run_update_code(command);
557 mutex_unlock(&ftraced_lock);
560 static void ftrace_shutdown(void)
564 if (unlikely(ftrace_disabled))
567 mutex_lock(&ftraced_lock);
569 if (!ftraced_suspend)
570 command |= FTRACE_DISABLE_CALLS;
572 if (saved_ftrace_func != ftrace_trace_function) {
573 saved_ftrace_func = ftrace_trace_function;
574 command |= FTRACE_UPDATE_TRACE_FUNC;
577 if (!command || !ftrace_enabled)
580 ftrace_run_update_code(command);
582 mutex_unlock(&ftraced_lock);
585 static void ftrace_startup_sysctl(void)
587 int command = FTRACE_ENABLE_MCOUNT;
589 if (unlikely(ftrace_disabled))
592 mutex_lock(&ftraced_lock);
593 /* Force update next time */
594 saved_ftrace_func = NULL;
595 /* ftraced_suspend is true if we want ftrace running */
597 command |= FTRACE_ENABLE_CALLS;
599 ftrace_run_update_code(command);
600 mutex_unlock(&ftraced_lock);
603 static void ftrace_shutdown_sysctl(void)
605 int command = FTRACE_DISABLE_MCOUNT;
607 if (unlikely(ftrace_disabled))
610 mutex_lock(&ftraced_lock);
611 /* ftraced_suspend is true if ftrace is running */
613 command |= FTRACE_DISABLE_CALLS;
615 ftrace_run_update_code(command);
616 mutex_unlock(&ftraced_lock);
619 static cycle_t ftrace_update_time;
620 static unsigned long ftrace_update_cnt;
621 unsigned long ftrace_update_tot_cnt;
623 static int __ftrace_update_code(void *ignore)
625 struct dyn_ftrace *p;
626 struct hlist_node *t, *n;
627 int save_ftrace_enabled;
631 /* Don't be recording funcs now */
632 ftrace_record_suspend++;
633 save_ftrace_enabled = ftrace_enabled;
636 start = ftrace_now(raw_smp_processor_id());
637 ftrace_update_cnt = 0;
639 /* No locks needed, the machine is stopped! */
640 for (i = 0; i < FTRACE_HASHSIZE; i++) {
641 /* all CPUS are stopped, we are safe to modify code */
642 hlist_for_each_entry_safe(p, t, n, &ftrace_hash[i], node) {
643 /* Skip over failed records which have not been
645 if (p->flags & FTRACE_FL_FAILED)
648 /* Unconverted records are always at the head of the
649 * hash bucket. Once we encounter a converted record,
650 * simply skip over to the next bucket. Saves ftraced
651 * some processor cycles (ftrace does its bid for
652 * global warming :-p ). */
653 if (p->flags & (FTRACE_FL_CONVERTED))
656 if (ftrace_code_disable(p)) {
657 p->flags |= FTRACE_FL_CONVERTED;
660 if ((system_state == SYSTEM_BOOTING) ||
661 !kernel_text_address(p->ip)) {
670 stop = ftrace_now(raw_smp_processor_id());
671 ftrace_update_time = stop - start;
672 ftrace_update_tot_cnt += ftrace_update_cnt;
675 ftrace_enabled = save_ftrace_enabled;
676 ftrace_record_suspend--;
681 static int ftrace_update_code(void)
683 if (unlikely(ftrace_disabled) ||
684 !ftrace_enabled || !ftraced_trigger)
687 stop_machine_run(__ftrace_update_code, NULL, NR_CPUS);
692 static int ftraced(void *ignore)
696 while (!kthread_should_stop()) {
698 set_current_state(TASK_INTERRUPTIBLE);
700 /* check once a second */
701 schedule_timeout(HZ);
703 if (unlikely(ftrace_disabled))
706 mutex_lock(&ftrace_sysctl_lock);
707 mutex_lock(&ftraced_lock);
708 if (!ftraced_suspend && !ftraced_stop &&
709 ftrace_update_code()) {
710 usecs = nsecs_to_usecs(ftrace_update_time);
711 if (ftrace_update_tot_cnt > 100000) {
712 ftrace_update_tot_cnt = 0;
713 pr_info("hm, dftrace overflow: %lu change%s"
714 " (%lu total) in %lu usec%s\n",
716 ftrace_update_cnt != 1 ? "s" : "",
717 ftrace_update_tot_cnt,
718 usecs, usecs != 1 ? "s" : "");
723 mutex_unlock(&ftraced_lock);
724 mutex_unlock(&ftrace_sysctl_lock);
726 ftrace_shutdown_replenish();
728 __set_current_state(TASK_RUNNING);
732 static int __init ftrace_dyn_table_alloc(void)
734 struct ftrace_page *pg;
738 /* allocate a few pages */
739 ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
740 if (!ftrace_pages_start)
744 * Allocate a few more pages.
746 * TODO: have some parser search vmlinux before
747 * final linking to find all calls to ftrace.
749 * a) know how many pages to allocate.
751 * b) set up the table then.
753 * The dynamic code is still necessary for
757 pg = ftrace_pages = ftrace_pages_start;
759 cnt = NR_TO_INIT / ENTRIES_PER_PAGE;
761 for (i = 0; i < cnt; i++) {
762 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
764 /* If we fail, we'll try later anyway */
775 FTRACE_ITER_FILTER = (1 << 0),
776 FTRACE_ITER_CONT = (1 << 1),
777 FTRACE_ITER_NOTRACE = (1 << 2),
780 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
782 struct ftrace_iterator {
784 struct ftrace_page *pg;
787 unsigned char buffer[FTRACE_BUFF_MAX+1];
793 t_next(struct seq_file *m, void *v, loff_t *pos)
795 struct ftrace_iterator *iter = m->private;
796 struct dyn_ftrace *rec = NULL;
801 if (iter->idx >= iter->pg->index) {
802 if (iter->pg->next) {
803 iter->pg = iter->pg->next;
808 rec = &iter->pg->records[iter->idx++];
809 if ((rec->flags & FTRACE_FL_FAILED) ||
810 ((iter->flags & FTRACE_ITER_FILTER) &&
811 !(rec->flags & FTRACE_FL_FILTER)) ||
812 ((iter->flags & FTRACE_ITER_NOTRACE) &&
813 !(rec->flags & FTRACE_FL_NOTRACE))) {
824 static void *t_start(struct seq_file *m, loff_t *pos)
826 struct ftrace_iterator *iter = m->private;
830 if (*pos != iter->pos) {
831 for (p = t_next(m, p, &l); p && l < *pos; p = t_next(m, p, &l))
835 p = t_next(m, p, &l);
841 static void t_stop(struct seq_file *m, void *p)
845 static int t_show(struct seq_file *m, void *v)
847 struct dyn_ftrace *rec = v;
848 char str[KSYM_SYMBOL_LEN];
853 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
855 seq_printf(m, "%s\n", str);
860 static struct seq_operations show_ftrace_seq_ops = {
868 ftrace_avail_open(struct inode *inode, struct file *file)
870 struct ftrace_iterator *iter;
873 if (unlikely(ftrace_disabled))
876 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
880 iter->pg = ftrace_pages_start;
883 ret = seq_open(file, &show_ftrace_seq_ops);
885 struct seq_file *m = file->private_data;
895 int ftrace_avail_release(struct inode *inode, struct file *file)
897 struct seq_file *m = (struct seq_file *)file->private_data;
898 struct ftrace_iterator *iter = m->private;
900 seq_release(inode, file);
906 static void ftrace_filter_reset(int enable)
908 struct ftrace_page *pg;
909 struct dyn_ftrace *rec;
910 unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
913 /* keep kstop machine from running */
917 pg = ftrace_pages_start;
919 for (i = 0; i < pg->index; i++) {
920 rec = &pg->records[i];
921 if (rec->flags & FTRACE_FL_FAILED)
931 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
933 struct ftrace_iterator *iter;
936 if (unlikely(ftrace_disabled))
939 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
943 mutex_lock(&ftrace_regex_lock);
944 if ((file->f_mode & FMODE_WRITE) &&
945 !(file->f_flags & O_APPEND))
946 ftrace_filter_reset(enable);
948 if (file->f_mode & FMODE_READ) {
949 iter->pg = ftrace_pages_start;
951 iter->flags = enable ? FTRACE_ITER_FILTER :
954 ret = seq_open(file, &show_ftrace_seq_ops);
956 struct seq_file *m = file->private_data;
961 file->private_data = iter;
962 mutex_unlock(&ftrace_regex_lock);
968 ftrace_filter_open(struct inode *inode, struct file *file)
970 return ftrace_regex_open(inode, file, 1);
974 ftrace_notrace_open(struct inode *inode, struct file *file)
976 return ftrace_regex_open(inode, file, 0);
980 ftrace_regex_read(struct file *file, char __user *ubuf,
981 size_t cnt, loff_t *ppos)
983 if (file->f_mode & FMODE_READ)
984 return seq_read(file, ubuf, cnt, ppos);
990 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
994 if (file->f_mode & FMODE_READ)
995 ret = seq_lseek(file, offset, origin);
997 file->f_pos = ret = 1;
1010 ftrace_match(unsigned char *buff, int len, int enable)
1012 char str[KSYM_SYMBOL_LEN];
1013 char *search = NULL;
1014 struct ftrace_page *pg;
1015 struct dyn_ftrace *rec;
1016 int type = MATCH_FULL;
1017 unsigned long flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1018 unsigned i, match = 0, search_len = 0;
1020 for (i = 0; i < len; i++) {
1021 if (buff[i] == '*') {
1023 search = buff + i + 1;
1024 type = MATCH_END_ONLY;
1025 search_len = len - (i + 1);
1027 if (type == MATCH_END_ONLY) {
1028 type = MATCH_MIDDLE_ONLY;
1031 type = MATCH_FRONT_ONLY;
1039 /* keep kstop machine from running */
1042 ftrace_filtered = 1;
1043 pg = ftrace_pages_start;
1045 for (i = 0; i < pg->index; i++) {
1049 rec = &pg->records[i];
1050 if (rec->flags & FTRACE_FL_FAILED)
1052 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1055 if (strcmp(str, buff) == 0)
1058 case MATCH_FRONT_ONLY:
1059 if (memcmp(str, buff, match) == 0)
1062 case MATCH_MIDDLE_ONLY:
1063 if (strstr(str, search))
1066 case MATCH_END_ONLY:
1067 ptr = strstr(str, search);
1068 if (ptr && (ptr[search_len] == 0))
1081 ftrace_regex_write(struct file *file, const char __user *ubuf,
1082 size_t cnt, loff_t *ppos, int enable)
1084 struct ftrace_iterator *iter;
1089 if (!cnt || cnt < 0)
1092 mutex_lock(&ftrace_regex_lock);
1094 if (file->f_mode & FMODE_READ) {
1095 struct seq_file *m = file->private_data;
1098 iter = file->private_data;
1101 iter->flags &= ~FTRACE_ITER_CONT;
1102 iter->buffer_idx = 0;
1105 ret = get_user(ch, ubuf++);
1111 if (!(iter->flags & ~FTRACE_ITER_CONT)) {
1112 /* skip white space */
1113 while (cnt && isspace(ch)) {
1114 ret = get_user(ch, ubuf++);
1122 file->f_pos += read;
1127 iter->buffer_idx = 0;
1130 while (cnt && !isspace(ch)) {
1131 if (iter->buffer_idx < FTRACE_BUFF_MAX)
1132 iter->buffer[iter->buffer_idx++] = ch;
1137 ret = get_user(ch, ubuf++);
1146 iter->buffer[iter->buffer_idx] = 0;
1147 ftrace_match(iter->buffer, iter->buffer_idx, enable);
1148 iter->buffer_idx = 0;
1150 iter->flags |= FTRACE_ITER_CONT;
1153 file->f_pos += read;
1157 mutex_unlock(&ftrace_regex_lock);
1163 ftrace_filter_write(struct file *file, const char __user *ubuf,
1164 size_t cnt, loff_t *ppos)
1166 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
1170 ftrace_notrace_write(struct file *file, const char __user *ubuf,
1171 size_t cnt, loff_t *ppos)
1173 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
1177 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
1179 if (unlikely(ftrace_disabled))
1182 mutex_lock(&ftrace_regex_lock);
1184 ftrace_filter_reset(enable);
1186 ftrace_match(buf, len, enable);
1187 mutex_unlock(&ftrace_regex_lock);
1191 * ftrace_set_filter - set a function to filter on in ftrace
1192 * @buf - the string that holds the function filter text.
1193 * @len - the length of the string.
1194 * @reset - non zero to reset all filters before applying this filter.
1196 * Filters denote which functions should be enabled when tracing is enabled.
1197 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
1199 void ftrace_set_filter(unsigned char *buf, int len, int reset)
1201 ftrace_set_regex(buf, len, reset, 1);
1205 * ftrace_set_notrace - set a function to not trace in ftrace
1206 * @buf - the string that holds the function notrace text.
1207 * @len - the length of the string.
1208 * @reset - non zero to reset all filters before applying this filter.
1210 * Notrace Filters denote which functions should not be enabled when tracing
1211 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
1214 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
1216 ftrace_set_regex(buf, len, reset, 0);
1220 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
1222 struct seq_file *m = (struct seq_file *)file->private_data;
1223 struct ftrace_iterator *iter;
1225 mutex_lock(&ftrace_regex_lock);
1226 if (file->f_mode & FMODE_READ) {
1229 seq_release(inode, file);
1231 iter = file->private_data;
1233 if (iter->buffer_idx) {
1235 iter->buffer[iter->buffer_idx] = 0;
1236 ftrace_match(iter->buffer, iter->buffer_idx, enable);
1239 mutex_lock(&ftrace_sysctl_lock);
1240 mutex_lock(&ftraced_lock);
1241 if (iter->filtered && ftraced_suspend && ftrace_enabled)
1242 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
1243 mutex_unlock(&ftraced_lock);
1244 mutex_unlock(&ftrace_sysctl_lock);
1247 mutex_unlock(&ftrace_regex_lock);
1252 ftrace_filter_release(struct inode *inode, struct file *file)
1254 return ftrace_regex_release(inode, file, 1);
1258 ftrace_notrace_release(struct inode *inode, struct file *file)
1260 return ftrace_regex_release(inode, file, 0);
1264 ftraced_read(struct file *filp, char __user *ubuf,
1265 size_t cnt, loff_t *ppos)
1267 /* don't worry about races */
1268 char *buf = ftraced_stop ? "disabled\n" : "enabled\n";
1269 int r = strlen(buf);
1271 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1275 ftraced_write(struct file *filp, const char __user *ubuf,
1276 size_t cnt, loff_t *ppos)
1282 if (cnt >= sizeof(buf))
1285 if (copy_from_user(&buf, ubuf, cnt))
1288 if (strncmp(buf, "enable", 6) == 0)
1290 else if (strncmp(buf, "disable", 7) == 0)
1295 ret = strict_strtoul(buf, 10, &val);
1303 ftrace_enable_daemon();
1305 ftrace_disable_daemon();
1312 static struct file_operations ftrace_avail_fops = {
1313 .open = ftrace_avail_open,
1315 .llseek = seq_lseek,
1316 .release = ftrace_avail_release,
1319 static struct file_operations ftrace_filter_fops = {
1320 .open = ftrace_filter_open,
1321 .read = ftrace_regex_read,
1322 .write = ftrace_filter_write,
1323 .llseek = ftrace_regex_lseek,
1324 .release = ftrace_filter_release,
1327 static struct file_operations ftrace_notrace_fops = {
1328 .open = ftrace_notrace_open,
1329 .read = ftrace_regex_read,
1330 .write = ftrace_notrace_write,
1331 .llseek = ftrace_regex_lseek,
1332 .release = ftrace_notrace_release,
1335 static struct file_operations ftraced_fops = {
1336 .open = tracing_open_generic,
1337 .read = ftraced_read,
1338 .write = ftraced_write,
1342 * ftrace_force_update - force an update to all recording ftrace functions
1344 int ftrace_force_update(void)
1348 if (unlikely(ftrace_disabled))
1351 mutex_lock(&ftrace_sysctl_lock);
1352 mutex_lock(&ftraced_lock);
1355 * If ftraced_trigger is not set, then there is nothing
1358 if (ftraced_trigger && !ftrace_update_code())
1361 mutex_unlock(&ftraced_lock);
1362 mutex_unlock(&ftrace_sysctl_lock);
1367 static void ftrace_force_shutdown(void)
1369 struct task_struct *task;
1370 int command = FTRACE_DISABLE_CALLS | FTRACE_UPDATE_TRACE_FUNC;
1372 mutex_lock(&ftraced_lock);
1373 task = ftraced_task;
1374 ftraced_task = NULL;
1375 ftraced_suspend = -1;
1376 ftrace_run_update_code(command);
1377 mutex_unlock(&ftraced_lock);
1383 static __init int ftrace_init_debugfs(void)
1385 struct dentry *d_tracer;
1386 struct dentry *entry;
1388 d_tracer = tracing_init_dentry();
1390 entry = debugfs_create_file("available_filter_functions", 0444,
1391 d_tracer, NULL, &ftrace_avail_fops);
1393 pr_warning("Could not create debugfs "
1394 "'available_filter_functions' entry\n");
1396 entry = debugfs_create_file("set_ftrace_filter", 0644, d_tracer,
1397 NULL, &ftrace_filter_fops);
1399 pr_warning("Could not create debugfs "
1400 "'set_ftrace_filter' entry\n");
1402 entry = debugfs_create_file("set_ftrace_notrace", 0644, d_tracer,
1403 NULL, &ftrace_notrace_fops);
1405 pr_warning("Could not create debugfs "
1406 "'set_ftrace_notrace' entry\n");
1408 entry = debugfs_create_file("ftraced_enabled", 0644, d_tracer,
1409 NULL, &ftraced_fops);
1411 pr_warning("Could not create debugfs "
1412 "'ftraced_enabled' entry\n");
1416 fs_initcall(ftrace_init_debugfs);
1418 static int __init ftrace_dynamic_init(void)
1420 struct task_struct *p;
1424 addr = (unsigned long)ftrace_record_ip;
1426 stop_machine_run(ftrace_dyn_arch_init, &addr, NR_CPUS);
1428 /* ftrace_dyn_arch_init places the return code in addr */
1434 ret = ftrace_dyn_table_alloc();
1438 p = kthread_run(ftraced, NULL, "ftraced");
1444 last_ftrace_enabled = ftrace_enabled = 1;
1450 ftrace_disabled = 1;
1454 core_initcall(ftrace_dynamic_init);
1456 # define ftrace_startup() do { } while (0)
1457 # define ftrace_shutdown() do { } while (0)
1458 # define ftrace_startup_sysctl() do { } while (0)
1459 # define ftrace_shutdown_sysctl() do { } while (0)
1460 # define ftrace_force_shutdown() do { } while (0)
1461 #endif /* CONFIG_DYNAMIC_FTRACE */
1464 * ftrace_kill - totally shutdown ftrace
1466 * This is a safety measure. If something was detected that seems
1467 * wrong, calling this function will keep ftrace from doing
1468 * any more modifications, and updates.
1469 * used when something went wrong.
1471 void ftrace_kill(void)
1473 mutex_lock(&ftrace_sysctl_lock);
1474 ftrace_disabled = 1;
1477 clear_ftrace_function();
1478 mutex_unlock(&ftrace_sysctl_lock);
1480 /* Try to totally disable ftrace */
1481 ftrace_force_shutdown();
1485 * register_ftrace_function - register a function for profiling
1486 * @ops - ops structure that holds the function for profiling.
1488 * Register a function to be called by all functions in the
1491 * Note: @ops->func and all the functions it calls must be labeled
1492 * with "notrace", otherwise it will go into a
1495 int register_ftrace_function(struct ftrace_ops *ops)
1499 if (unlikely(ftrace_disabled))
1502 mutex_lock(&ftrace_sysctl_lock);
1503 ret = __register_ftrace_function(ops);
1505 mutex_unlock(&ftrace_sysctl_lock);
1511 * unregister_ftrace_function - unresgister a function for profiling.
1512 * @ops - ops structure that holds the function to unregister
1514 * Unregister a function that was added to be called by ftrace profiling.
1516 int unregister_ftrace_function(struct ftrace_ops *ops)
1520 mutex_lock(&ftrace_sysctl_lock);
1521 ret = __unregister_ftrace_function(ops);
1523 mutex_unlock(&ftrace_sysctl_lock);
1529 ftrace_enable_sysctl(struct ctl_table *table, int write,
1530 struct file *file, void __user *buffer, size_t *lenp,
1535 if (unlikely(ftrace_disabled))
1538 mutex_lock(&ftrace_sysctl_lock);
1540 ret = proc_dointvec(table, write, file, buffer, lenp, ppos);
1542 if (ret || !write || (last_ftrace_enabled == ftrace_enabled))
1545 last_ftrace_enabled = ftrace_enabled;
1547 if (ftrace_enabled) {
1549 ftrace_startup_sysctl();
1551 /* we are starting ftrace again */
1552 if (ftrace_list != &ftrace_list_end) {
1553 if (ftrace_list->next == &ftrace_list_end)
1554 ftrace_trace_function = ftrace_list->func;
1556 ftrace_trace_function = ftrace_list_func;
1560 /* stopping ftrace calls (just send to ftrace_stub) */
1561 ftrace_trace_function = ftrace_stub;
1563 ftrace_shutdown_sysctl();
1567 mutex_unlock(&ftrace_sysctl_lock);