2 * Infrastructure for profiling code inserted by 'gcc -pg'.
4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
7 * Originally ported from the -rt patch by:
8 * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
10 * Based on code in the latency_tracer, that is:
12 * Copyright (C) 2004-2006 Ingo Molnar
13 * Copyright (C) 2004 William Lee Irwin III
16 #include <linux/stop_machine.h>
17 #include <linux/clocksource.h>
18 #include <linux/kallsyms.h>
19 #include <linux/seq_file.h>
20 #include <linux/suspend.h>
21 #include <linux/debugfs.h>
22 #include <linux/hardirq.h>
23 #include <linux/kthread.h>
24 #include <linux/uaccess.h>
25 #include <linux/kprobes.h>
26 #include <linux/ftrace.h>
27 #include <linux/sysctl.h>
28 #include <linux/ctype.h>
29 #include <linux/list.h>
30 #include <linux/hash.h>
32 #include <trace/sched.h>
34 #include <asm/ftrace.h>
38 #define FTRACE_WARN_ON(cond) \
44 #define FTRACE_WARN_ON_ONCE(cond) \
46 if (WARN_ON_ONCE(cond)) \
50 /* hash bits for specific function selection */
51 #define FTRACE_HASH_BITS 7
52 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
54 /* ftrace_enabled is a method to turn ftrace on or off */
55 int ftrace_enabled __read_mostly;
56 static int last_ftrace_enabled;
58 /* Quick disabling of function tracer. */
59 int function_trace_stop;
62 * ftrace_disabled is set when an anomaly is discovered.
63 * ftrace_disabled is much stronger than ftrace_enabled.
65 static int ftrace_disabled __read_mostly;
67 static DEFINE_MUTEX(ftrace_lock);
69 static struct ftrace_ops ftrace_list_end __read_mostly =
74 static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
75 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
76 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
77 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
79 static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
81 struct ftrace_ops *op = ftrace_list;
83 /* in case someone actually ports this to alpha! */
84 read_barrier_depends();
86 while (op != &ftrace_list_end) {
88 read_barrier_depends();
89 op->func(ip, parent_ip);
94 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
96 if (!test_tsk_trace_trace(current))
99 ftrace_pid_function(ip, parent_ip);
102 static void set_ftrace_pid_function(ftrace_func_t func)
104 /* do not set ftrace_pid_function to itself! */
105 if (func != ftrace_pid_func)
106 ftrace_pid_function = func;
110 * clear_ftrace_function - reset the ftrace function
112 * This NULLs the ftrace function and in essence stops
113 * tracing. There may be lag
115 void clear_ftrace_function(void)
117 ftrace_trace_function = ftrace_stub;
118 __ftrace_trace_function = ftrace_stub;
119 ftrace_pid_function = ftrace_stub;
122 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
124 * For those archs that do not test ftrace_trace_stop in their
125 * mcount call site, we need to do it from C.
127 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
129 if (function_trace_stop)
132 __ftrace_trace_function(ip, parent_ip);
136 static int __register_ftrace_function(struct ftrace_ops *ops)
138 ops->next = ftrace_list;
140 * We are entering ops into the ftrace_list but another
141 * CPU might be walking that list. We need to make sure
142 * the ops->next pointer is valid before another CPU sees
143 * the ops pointer included into the ftrace_list.
148 if (ftrace_enabled) {
151 if (ops->next == &ftrace_list_end)
154 func = ftrace_list_func;
156 if (ftrace_pid_trace) {
157 set_ftrace_pid_function(func);
158 func = ftrace_pid_func;
162 * For one func, simply call it directly.
163 * For more than one func, call the chain.
165 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
166 ftrace_trace_function = func;
168 __ftrace_trace_function = func;
169 ftrace_trace_function = ftrace_test_stop_func;
176 static int __unregister_ftrace_function(struct ftrace_ops *ops)
178 struct ftrace_ops **p;
181 * If we are removing the last function, then simply point
182 * to the ftrace_stub.
184 if (ftrace_list == ops && ops->next == &ftrace_list_end) {
185 ftrace_trace_function = ftrace_stub;
186 ftrace_list = &ftrace_list_end;
190 for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
199 if (ftrace_enabled) {
200 /* If we only have one func left, then call that directly */
201 if (ftrace_list->next == &ftrace_list_end) {
202 ftrace_func_t func = ftrace_list->func;
204 if (ftrace_pid_trace) {
205 set_ftrace_pid_function(func);
206 func = ftrace_pid_func;
208 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
209 ftrace_trace_function = func;
211 __ftrace_trace_function = func;
219 static void ftrace_update_pid_func(void)
223 if (ftrace_trace_function == ftrace_stub)
226 func = ftrace_trace_function;
228 if (ftrace_pid_trace) {
229 set_ftrace_pid_function(func);
230 func = ftrace_pid_func;
232 if (func == ftrace_pid_func)
233 func = ftrace_pid_function;
236 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
237 ftrace_trace_function = func;
239 __ftrace_trace_function = func;
243 /* set when tracing only a pid */
244 struct pid *ftrace_pid_trace;
245 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
247 #ifdef CONFIG_DYNAMIC_FTRACE
249 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
250 # error Dynamic ftrace depends on MCOUNT_RECORD
253 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
255 struct ftrace_func_probe {
256 struct hlist_node node;
257 struct ftrace_probe_ops *ops;
266 FTRACE_ENABLE_CALLS = (1 << 0),
267 FTRACE_DISABLE_CALLS = (1 << 1),
268 FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
269 FTRACE_ENABLE_MCOUNT = (1 << 3),
270 FTRACE_DISABLE_MCOUNT = (1 << 4),
271 FTRACE_START_FUNC_RET = (1 << 5),
272 FTRACE_STOP_FUNC_RET = (1 << 6),
275 static int ftrace_filtered;
277 static struct dyn_ftrace *ftrace_new_addrs;
279 static DEFINE_MUTEX(ftrace_regex_lock);
282 struct ftrace_page *next;
284 struct dyn_ftrace records[];
287 #define ENTRIES_PER_PAGE \
288 ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
290 /* estimate from running different kernels */
291 #define NR_TO_INIT 10000
293 static struct ftrace_page *ftrace_pages_start;
294 static struct ftrace_page *ftrace_pages;
296 static struct dyn_ftrace *ftrace_free_records;
299 * This is a double for. Do not use 'break' to break out of the loop,
300 * you must use a goto.
302 #define do_for_each_ftrace_rec(pg, rec) \
303 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
305 for (_____i = 0; _____i < pg->index; _____i++) { \
306 rec = &pg->records[_____i];
308 #define while_for_each_ftrace_rec() \
312 #ifdef CONFIG_KPROBES
314 static int frozen_record_count;
316 static inline void freeze_record(struct dyn_ftrace *rec)
318 if (!(rec->flags & FTRACE_FL_FROZEN)) {
319 rec->flags |= FTRACE_FL_FROZEN;
320 frozen_record_count++;
324 static inline void unfreeze_record(struct dyn_ftrace *rec)
326 if (rec->flags & FTRACE_FL_FROZEN) {
327 rec->flags &= ~FTRACE_FL_FROZEN;
328 frozen_record_count--;
332 static inline int record_frozen(struct dyn_ftrace *rec)
334 return rec->flags & FTRACE_FL_FROZEN;
337 # define freeze_record(rec) ({ 0; })
338 # define unfreeze_record(rec) ({ 0; })
339 # define record_frozen(rec) ({ 0; })
340 #endif /* CONFIG_KPROBES */
342 static void ftrace_free_rec(struct dyn_ftrace *rec)
344 rec->ip = (unsigned long)ftrace_free_records;
345 ftrace_free_records = rec;
346 rec->flags |= FTRACE_FL_FREE;
349 void ftrace_release(void *start, unsigned long size)
351 struct dyn_ftrace *rec;
352 struct ftrace_page *pg;
353 unsigned long s = (unsigned long)start;
354 unsigned long e = s + size;
356 if (ftrace_disabled || !start)
359 mutex_lock(&ftrace_lock);
360 do_for_each_ftrace_rec(pg, rec) {
361 if ((rec->ip >= s) && (rec->ip < e) &&
362 !(rec->flags & FTRACE_FL_FREE))
363 ftrace_free_rec(rec);
364 } while_for_each_ftrace_rec();
365 mutex_unlock(&ftrace_lock);
368 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
370 struct dyn_ftrace *rec;
372 /* First check for freed records */
373 if (ftrace_free_records) {
374 rec = ftrace_free_records;
376 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
377 FTRACE_WARN_ON_ONCE(1);
378 ftrace_free_records = NULL;
382 ftrace_free_records = (void *)rec->ip;
383 memset(rec, 0, sizeof(*rec));
387 if (ftrace_pages->index == ENTRIES_PER_PAGE) {
388 if (!ftrace_pages->next) {
389 /* allocate another page */
391 (void *)get_zeroed_page(GFP_KERNEL);
392 if (!ftrace_pages->next)
395 ftrace_pages = ftrace_pages->next;
398 return &ftrace_pages->records[ftrace_pages->index++];
401 static struct dyn_ftrace *
402 ftrace_record_ip(unsigned long ip)
404 struct dyn_ftrace *rec;
409 rec = ftrace_alloc_dyn_node(ip);
414 rec->flags = (unsigned long)ftrace_new_addrs;
415 ftrace_new_addrs = rec;
420 static void print_ip_ins(const char *fmt, unsigned char *p)
424 printk(KERN_CONT "%s", fmt);
426 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
427 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
430 static void ftrace_bug(int failed, unsigned long ip)
434 FTRACE_WARN_ON_ONCE(1);
435 pr_info("ftrace faulted on modifying ");
439 FTRACE_WARN_ON_ONCE(1);
440 pr_info("ftrace failed to modify ");
442 print_ip_ins(" actual: ", (unsigned char *)ip);
443 printk(KERN_CONT "\n");
446 FTRACE_WARN_ON_ONCE(1);
447 pr_info("ftrace faulted on writing ");
451 FTRACE_WARN_ON_ONCE(1);
452 pr_info("ftrace faulted on unknown error ");
459 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
461 unsigned long ftrace_addr;
462 unsigned long ip, fl;
464 ftrace_addr = (unsigned long)FTRACE_ADDR;
469 * If this record is not to be traced and
470 * it is not enabled then do nothing.
472 * If this record is not to be traced and
473 * it is enabled then disable it.
476 if (rec->flags & FTRACE_FL_NOTRACE) {
477 if (rec->flags & FTRACE_FL_ENABLED)
478 rec->flags &= ~FTRACE_FL_ENABLED;
482 } else if (ftrace_filtered && enable) {
487 fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED);
489 /* Record is filtered and enabled, do nothing */
490 if (fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED))
493 /* Record is not filtered or enabled, do nothing */
497 /* Record is not filtered but enabled, disable it */
498 if (fl == FTRACE_FL_ENABLED)
499 rec->flags &= ~FTRACE_FL_ENABLED;
501 /* Otherwise record is filtered but not enabled, enable it */
502 rec->flags |= FTRACE_FL_ENABLED;
504 /* Disable or not filtered */
507 /* if record is enabled, do nothing */
508 if (rec->flags & FTRACE_FL_ENABLED)
511 rec->flags |= FTRACE_FL_ENABLED;
515 /* if record is not enabled, do nothing */
516 if (!(rec->flags & FTRACE_FL_ENABLED))
519 rec->flags &= ~FTRACE_FL_ENABLED;
523 if (rec->flags & FTRACE_FL_ENABLED)
524 return ftrace_make_call(rec, ftrace_addr);
526 return ftrace_make_nop(NULL, rec, ftrace_addr);
529 static void ftrace_replace_code(int enable)
531 struct dyn_ftrace *rec;
532 struct ftrace_page *pg;
535 do_for_each_ftrace_rec(pg, rec) {
537 * Skip over free records, records that have
538 * failed and not converted.
540 if (rec->flags & FTRACE_FL_FREE ||
541 rec->flags & FTRACE_FL_FAILED ||
542 !(rec->flags & FTRACE_FL_CONVERTED))
545 /* ignore updates to this record's mcount site */
546 if (get_kprobe((void *)rec->ip)) {
550 unfreeze_record(rec);
553 failed = __ftrace_replace_code(rec, enable);
555 rec->flags |= FTRACE_FL_FAILED;
556 if ((system_state == SYSTEM_BOOTING) ||
557 !core_kernel_text(rec->ip)) {
558 ftrace_free_rec(rec);
560 ftrace_bug(failed, rec->ip);
561 /* Stop processing */
565 } while_for_each_ftrace_rec();
569 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
576 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
579 rec->flags |= FTRACE_FL_FAILED;
586 * archs can override this function if they must do something
587 * before the modifying code is performed.
589 int __weak ftrace_arch_code_modify_prepare(void)
595 * archs can override this function if they must do something
596 * after the modifying code is performed.
598 int __weak ftrace_arch_code_modify_post_process(void)
603 static int __ftrace_modify_code(void *data)
607 if (*command & FTRACE_ENABLE_CALLS)
608 ftrace_replace_code(1);
609 else if (*command & FTRACE_DISABLE_CALLS)
610 ftrace_replace_code(0);
612 if (*command & FTRACE_UPDATE_TRACE_FUNC)
613 ftrace_update_ftrace_func(ftrace_trace_function);
615 if (*command & FTRACE_START_FUNC_RET)
616 ftrace_enable_ftrace_graph_caller();
617 else if (*command & FTRACE_STOP_FUNC_RET)
618 ftrace_disable_ftrace_graph_caller();
623 static void ftrace_run_update_code(int command)
627 ret = ftrace_arch_code_modify_prepare();
632 stop_machine(__ftrace_modify_code, &command, NULL);
634 ret = ftrace_arch_code_modify_post_process();
638 static ftrace_func_t saved_ftrace_func;
639 static int ftrace_start_up;
641 static void ftrace_startup_enable(int command)
643 if (saved_ftrace_func != ftrace_trace_function) {
644 saved_ftrace_func = ftrace_trace_function;
645 command |= FTRACE_UPDATE_TRACE_FUNC;
648 if (!command || !ftrace_enabled)
651 ftrace_run_update_code(command);
654 static void ftrace_startup(int command)
656 if (unlikely(ftrace_disabled))
660 command |= FTRACE_ENABLE_CALLS;
662 ftrace_startup_enable(command);
665 static void ftrace_shutdown(int command)
667 if (unlikely(ftrace_disabled))
671 if (!ftrace_start_up)
672 command |= FTRACE_DISABLE_CALLS;
674 if (saved_ftrace_func != ftrace_trace_function) {
675 saved_ftrace_func = ftrace_trace_function;
676 command |= FTRACE_UPDATE_TRACE_FUNC;
679 if (!command || !ftrace_enabled)
682 ftrace_run_update_code(command);
685 static void ftrace_startup_sysctl(void)
687 int command = FTRACE_ENABLE_MCOUNT;
689 if (unlikely(ftrace_disabled))
692 /* Force update next time */
693 saved_ftrace_func = NULL;
694 /* ftrace_start_up is true if we want ftrace running */
696 command |= FTRACE_ENABLE_CALLS;
698 ftrace_run_update_code(command);
701 static void ftrace_shutdown_sysctl(void)
703 int command = FTRACE_DISABLE_MCOUNT;
705 if (unlikely(ftrace_disabled))
708 /* ftrace_start_up is true if ftrace is running */
710 command |= FTRACE_DISABLE_CALLS;
712 ftrace_run_update_code(command);
715 static cycle_t ftrace_update_time;
716 static unsigned long ftrace_update_cnt;
717 unsigned long ftrace_update_tot_cnt;
719 static int ftrace_update_code(struct module *mod)
721 struct dyn_ftrace *p;
724 start = ftrace_now(raw_smp_processor_id());
725 ftrace_update_cnt = 0;
727 while (ftrace_new_addrs) {
729 /* If something went wrong, bail without enabling anything */
730 if (unlikely(ftrace_disabled))
733 p = ftrace_new_addrs;
734 ftrace_new_addrs = (struct dyn_ftrace *)p->flags;
737 /* convert record (i.e, patch mcount-call with NOP) */
738 if (ftrace_code_disable(mod, p)) {
739 p->flags |= FTRACE_FL_CONVERTED;
745 stop = ftrace_now(raw_smp_processor_id());
746 ftrace_update_time = stop - start;
747 ftrace_update_tot_cnt += ftrace_update_cnt;
752 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
754 struct ftrace_page *pg;
758 /* allocate a few pages */
759 ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
760 if (!ftrace_pages_start)
764 * Allocate a few more pages.
766 * TODO: have some parser search vmlinux before
767 * final linking to find all calls to ftrace.
769 * a) know how many pages to allocate.
771 * b) set up the table then.
773 * The dynamic code is still necessary for
777 pg = ftrace_pages = ftrace_pages_start;
779 cnt = num_to_init / ENTRIES_PER_PAGE;
780 pr_info("ftrace: allocating %ld entries in %d pages\n",
781 num_to_init, cnt + 1);
783 for (i = 0; i < cnt; i++) {
784 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
786 /* If we fail, we'll try later anyway */
797 FTRACE_ITER_FILTER = (1 << 0),
798 FTRACE_ITER_CONT = (1 << 1),
799 FTRACE_ITER_NOTRACE = (1 << 2),
800 FTRACE_ITER_FAILURES = (1 << 3),
801 FTRACE_ITER_PRINTALL = (1 << 4),
802 FTRACE_ITER_HASH = (1 << 5),
805 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
807 struct ftrace_iterator {
808 struct ftrace_page *pg;
812 unsigned char buffer[FTRACE_BUFF_MAX+1];
818 t_hash_next(struct seq_file *m, void *v, loff_t *pos)
820 struct ftrace_iterator *iter = m->private;
821 struct hlist_node *hnd = v;
822 struct hlist_head *hhd;
824 WARN_ON(!(iter->flags & FTRACE_ITER_HASH));
829 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
832 hhd = &ftrace_func_hash[iter->hidx];
834 if (hlist_empty(hhd)) {
853 static void *t_hash_start(struct seq_file *m, loff_t *pos)
855 struct ftrace_iterator *iter = m->private;
858 iter->flags |= FTRACE_ITER_HASH;
860 return t_hash_next(m, p, pos);
863 static int t_hash_show(struct seq_file *m, void *v)
865 struct ftrace_func_probe *rec;
866 struct hlist_node *hnd = v;
867 char str[KSYM_SYMBOL_LEN];
869 rec = hlist_entry(hnd, struct ftrace_func_probe, node);
872 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
874 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
875 seq_printf(m, "%s:", str);
877 kallsyms_lookup((unsigned long)rec->ops->func, NULL, NULL, NULL, str);
878 seq_printf(m, "%s", str);
881 seq_printf(m, ":%p", rec->data);
888 t_next(struct seq_file *m, void *v, loff_t *pos)
890 struct ftrace_iterator *iter = m->private;
891 struct dyn_ftrace *rec = NULL;
893 if (iter->flags & FTRACE_ITER_HASH)
894 return t_hash_next(m, v, pos);
898 if (iter->flags & FTRACE_ITER_PRINTALL)
902 if (iter->idx >= iter->pg->index) {
903 if (iter->pg->next) {
904 iter->pg = iter->pg->next;
911 rec = &iter->pg->records[iter->idx++];
912 if ((rec->flags & FTRACE_FL_FREE) ||
914 (!(iter->flags & FTRACE_ITER_FAILURES) &&
915 (rec->flags & FTRACE_FL_FAILED)) ||
917 ((iter->flags & FTRACE_ITER_FAILURES) &&
918 !(rec->flags & FTRACE_FL_FAILED)) ||
920 ((iter->flags & FTRACE_ITER_FILTER) &&
921 !(rec->flags & FTRACE_FL_FILTER)) ||
923 ((iter->flags & FTRACE_ITER_NOTRACE) &&
924 !(rec->flags & FTRACE_FL_NOTRACE))) {
933 static void *t_start(struct seq_file *m, loff_t *pos)
935 struct ftrace_iterator *iter = m->private;
938 mutex_lock(&ftrace_lock);
940 * For set_ftrace_filter reading, if we have the filter
941 * off, we can short cut and just print out that all
942 * functions are enabled.
944 if (iter->flags & FTRACE_ITER_FILTER && !ftrace_filtered) {
946 return t_hash_start(m, pos);
947 iter->flags |= FTRACE_ITER_PRINTALL;
952 if (iter->flags & FTRACE_ITER_HASH)
953 return t_hash_start(m, pos);
962 p = t_next(m, p, pos);
965 return t_hash_start(m, pos);
970 static void t_stop(struct seq_file *m, void *p)
972 mutex_unlock(&ftrace_lock);
975 static int t_show(struct seq_file *m, void *v)
977 struct ftrace_iterator *iter = m->private;
978 struct dyn_ftrace *rec = v;
979 char str[KSYM_SYMBOL_LEN];
981 if (iter->flags & FTRACE_ITER_HASH)
982 return t_hash_show(m, v);
984 if (iter->flags & FTRACE_ITER_PRINTALL) {
985 seq_printf(m, "#### all functions enabled ####\n");
992 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
994 seq_printf(m, "%s\n", str);
999 static struct seq_operations show_ftrace_seq_ops = {
1007 ftrace_avail_open(struct inode *inode, struct file *file)
1009 struct ftrace_iterator *iter;
1012 if (unlikely(ftrace_disabled))
1015 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1019 iter->pg = ftrace_pages_start;
1021 ret = seq_open(file, &show_ftrace_seq_ops);
1023 struct seq_file *m = file->private_data;
1033 int ftrace_avail_release(struct inode *inode, struct file *file)
1035 struct seq_file *m = (struct seq_file *)file->private_data;
1036 struct ftrace_iterator *iter = m->private;
1038 seq_release(inode, file);
1045 ftrace_failures_open(struct inode *inode, struct file *file)
1049 struct ftrace_iterator *iter;
1051 ret = ftrace_avail_open(inode, file);
1053 m = (struct seq_file *)file->private_data;
1054 iter = (struct ftrace_iterator *)m->private;
1055 iter->flags = FTRACE_ITER_FAILURES;
1062 static void ftrace_filter_reset(int enable)
1064 struct ftrace_page *pg;
1065 struct dyn_ftrace *rec;
1066 unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1068 mutex_lock(&ftrace_lock);
1070 ftrace_filtered = 0;
1071 do_for_each_ftrace_rec(pg, rec) {
1072 if (rec->flags & FTRACE_FL_FAILED)
1074 rec->flags &= ~type;
1075 } while_for_each_ftrace_rec();
1076 mutex_unlock(&ftrace_lock);
1080 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
1082 struct ftrace_iterator *iter;
1085 if (unlikely(ftrace_disabled))
1088 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1092 mutex_lock(&ftrace_regex_lock);
1093 if ((file->f_mode & FMODE_WRITE) &&
1094 !(file->f_flags & O_APPEND))
1095 ftrace_filter_reset(enable);
1097 if (file->f_mode & FMODE_READ) {
1098 iter->pg = ftrace_pages_start;
1099 iter->flags = enable ? FTRACE_ITER_FILTER :
1100 FTRACE_ITER_NOTRACE;
1102 ret = seq_open(file, &show_ftrace_seq_ops);
1104 struct seq_file *m = file->private_data;
1109 file->private_data = iter;
1110 mutex_unlock(&ftrace_regex_lock);
1116 ftrace_filter_open(struct inode *inode, struct file *file)
1118 return ftrace_regex_open(inode, file, 1);
1122 ftrace_notrace_open(struct inode *inode, struct file *file)
1124 return ftrace_regex_open(inode, file, 0);
1128 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1132 if (file->f_mode & FMODE_READ)
1133 ret = seq_lseek(file, offset, origin);
1135 file->f_pos = ret = 1;
1148 * (static function - no need for kernel doc)
1150 * Pass in a buffer containing a glob and this function will
1151 * set search to point to the search part of the buffer and
1152 * return the type of search it is (see enum above).
1153 * This does modify buff.
1155 * Returns enum type.
1156 * search returns the pointer to use for comparison.
1157 * not returns 1 if buff started with a '!'
1161 ftrace_setup_glob(char *buff, int len, char **search, int *not)
1163 int type = MATCH_FULL;
1166 if (buff[0] == '!') {
1175 for (i = 0; i < len; i++) {
1176 if (buff[i] == '*') {
1179 type = MATCH_END_ONLY;
1181 if (type == MATCH_END_ONLY)
1182 type = MATCH_MIDDLE_ONLY;
1184 type = MATCH_FRONT_ONLY;
1194 static int ftrace_match(char *str, char *regex, int len, int type)
1201 if (strcmp(str, regex) == 0)
1204 case MATCH_FRONT_ONLY:
1205 if (strncmp(str, regex, len) == 0)
1208 case MATCH_MIDDLE_ONLY:
1209 if (strstr(str, regex))
1212 case MATCH_END_ONLY:
1213 ptr = strstr(str, regex);
1214 if (ptr && (ptr[len] == 0))
1223 ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
1225 char str[KSYM_SYMBOL_LEN];
1227 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1228 return ftrace_match(str, regex, len, type);
1231 static void ftrace_match_records(char *buff, int len, int enable)
1233 unsigned int search_len;
1234 struct ftrace_page *pg;
1235 struct dyn_ftrace *rec;
1241 flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1242 type = ftrace_setup_glob(buff, len, &search, ¬);
1244 search_len = strlen(search);
1246 mutex_lock(&ftrace_lock);
1247 do_for_each_ftrace_rec(pg, rec) {
1249 if (rec->flags & FTRACE_FL_FAILED)
1252 if (ftrace_match_record(rec, search, search_len, type)) {
1254 rec->flags &= ~flag;
1259 * Only enable filtering if we have a function that
1262 if (enable && (rec->flags & FTRACE_FL_FILTER))
1263 ftrace_filtered = 1;
1264 } while_for_each_ftrace_rec();
1265 mutex_unlock(&ftrace_lock);
1269 ftrace_match_module_record(struct dyn_ftrace *rec, char *mod,
1270 char *regex, int len, int type)
1272 char str[KSYM_SYMBOL_LEN];
1275 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
1277 if (!modname || strcmp(modname, mod))
1280 /* blank search means to match all funcs in the mod */
1282 return ftrace_match(str, regex, len, type);
1287 static void ftrace_match_module_records(char *buff, char *mod, int enable)
1289 unsigned search_len = 0;
1290 struct ftrace_page *pg;
1291 struct dyn_ftrace *rec;
1292 int type = MATCH_FULL;
1293 char *search = buff;
1297 flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1299 /* blank or '*' mean the same */
1300 if (strcmp(buff, "*") == 0)
1303 /* handle the case of 'dont filter this module' */
1304 if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
1310 type = ftrace_setup_glob(buff, strlen(buff), &search, ¬);
1311 search_len = strlen(search);
1314 mutex_lock(&ftrace_lock);
1315 do_for_each_ftrace_rec(pg, rec) {
1317 if (rec->flags & FTRACE_FL_FAILED)
1320 if (ftrace_match_module_record(rec, mod,
1321 search, search_len, type)) {
1323 rec->flags &= ~flag;
1327 if (enable && (rec->flags & FTRACE_FL_FILTER))
1328 ftrace_filtered = 1;
1330 } while_for_each_ftrace_rec();
1331 mutex_unlock(&ftrace_lock);
1335 * We register the module command as a template to show others how
1336 * to register the a command as well.
1340 ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
1345 * cmd == 'mod' because we only registered this func
1346 * for the 'mod' ftrace_func_command.
1347 * But if you register one func with multiple commands,
1348 * you can tell which command was used by the cmd
1352 /* we must have a module name */
1356 mod = strsep(¶m, ":");
1360 ftrace_match_module_records(func, mod, enable);
1364 static struct ftrace_func_command ftrace_mod_cmd = {
1366 .func = ftrace_mod_callback,
1369 static int __init ftrace_mod_cmd_init(void)
1371 return register_ftrace_command(&ftrace_mod_cmd);
1373 device_initcall(ftrace_mod_cmd_init);
1376 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
1378 struct ftrace_func_probe *entry;
1379 struct hlist_head *hhd;
1380 struct hlist_node *n;
1384 key = hash_long(ip, FTRACE_HASH_BITS);
1386 hhd = &ftrace_func_hash[key];
1388 if (hlist_empty(hhd))
1392 * Disable preemption for these calls to prevent a RCU grace
1393 * period. This syncs the hash iteration and freeing of items
1394 * on the hash. rcu_read_lock is too dangerous here.
1396 resched = ftrace_preempt_disable();
1397 hlist_for_each_entry_rcu(entry, n, hhd, node) {
1398 if (entry->ip == ip)
1399 entry->ops->func(ip, parent_ip, &entry->data);
1401 ftrace_preempt_enable(resched);
1404 static struct ftrace_ops trace_probe_ops __read_mostly =
1406 .func = function_trace_probe_call,
1409 static int ftrace_probe_registered;
1411 static void __enable_ftrace_function_probe(void)
1415 if (ftrace_probe_registered)
1418 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1419 struct hlist_head *hhd = &ftrace_func_hash[i];
1423 /* Nothing registered? */
1424 if (i == FTRACE_FUNC_HASHSIZE)
1427 __register_ftrace_function(&trace_probe_ops);
1429 ftrace_probe_registered = 1;
1432 static void __disable_ftrace_function_probe(void)
1436 if (!ftrace_probe_registered)
1439 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1440 struct hlist_head *hhd = &ftrace_func_hash[i];
1445 /* no more funcs left */
1446 __unregister_ftrace_function(&trace_probe_ops);
1448 ftrace_probe_registered = 0;
1452 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
1454 struct ftrace_func_probe *entry =
1455 container_of(rhp, struct ftrace_func_probe, rcu);
1457 if (entry->ops->free)
1458 entry->ops->free(&entry->data);
1464 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
1467 struct ftrace_func_probe *entry;
1468 struct ftrace_page *pg;
1469 struct dyn_ftrace *rec;
1475 type = ftrace_setup_glob(glob, strlen(glob), &search, ¬);
1476 len = strlen(search);
1478 /* we do not support '!' for function probes */
1482 mutex_lock(&ftrace_lock);
1483 do_for_each_ftrace_rec(pg, rec) {
1485 if (rec->flags & FTRACE_FL_FAILED)
1488 if (!ftrace_match_record(rec, search, len, type))
1491 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1493 /* If we did not process any, then return error */
1504 * The caller might want to do something special
1505 * for each function we find. We call the callback
1506 * to give the caller an opportunity to do so.
1508 if (ops->callback) {
1509 if (ops->callback(rec->ip, &entry->data) < 0) {
1510 /* caller does not like this func */
1517 entry->ip = rec->ip;
1519 key = hash_long(entry->ip, FTRACE_HASH_BITS);
1520 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
1522 } while_for_each_ftrace_rec();
1523 __enable_ftrace_function_probe();
1526 mutex_unlock(&ftrace_lock);
1532 PROBE_TEST_FUNC = 1,
1537 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
1538 void *data, int flags)
1540 struct ftrace_func_probe *entry;
1541 struct hlist_node *n, *tmp;
1542 char str[KSYM_SYMBOL_LEN];
1543 int type = MATCH_FULL;
1547 if (glob && (strcmp(glob, "*") || !strlen(glob)))
1552 type = ftrace_setup_glob(glob, strlen(glob), &search, ¬);
1553 len = strlen(search);
1555 /* we do not support '!' for function probes */
1560 mutex_lock(&ftrace_lock);
1561 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1562 struct hlist_head *hhd = &ftrace_func_hash[i];
1564 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
1566 /* break up if statements for readability */
1567 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
1570 if ((flags & PROBE_TEST_DATA) && entry->data != data)
1573 /* do this last, since it is the most expensive */
1575 kallsyms_lookup(entry->ip, NULL, NULL,
1577 if (!ftrace_match(str, glob, len, type))
1581 hlist_del(&entry->node);
1582 call_rcu(&entry->rcu, ftrace_free_entry_rcu);
1585 __disable_ftrace_function_probe();
1586 mutex_unlock(&ftrace_lock);
1590 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
1593 __unregister_ftrace_function_probe(glob, ops, data,
1594 PROBE_TEST_FUNC | PROBE_TEST_DATA);
1598 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
1600 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
1603 void unregister_ftrace_function_probe_all(char *glob)
1605 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
1608 static LIST_HEAD(ftrace_commands);
1609 static DEFINE_MUTEX(ftrace_cmd_mutex);
1611 int register_ftrace_command(struct ftrace_func_command *cmd)
1613 struct ftrace_func_command *p;
1616 mutex_lock(&ftrace_cmd_mutex);
1617 list_for_each_entry(p, &ftrace_commands, list) {
1618 if (strcmp(cmd->name, p->name) == 0) {
1623 list_add(&cmd->list, &ftrace_commands);
1625 mutex_unlock(&ftrace_cmd_mutex);
1630 int unregister_ftrace_command(struct ftrace_func_command *cmd)
1632 struct ftrace_func_command *p, *n;
1635 mutex_lock(&ftrace_cmd_mutex);
1636 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
1637 if (strcmp(cmd->name, p->name) == 0) {
1639 list_del_init(&p->list);
1644 mutex_unlock(&ftrace_cmd_mutex);
1649 static int ftrace_process_regex(char *buff, int len, int enable)
1651 char *func, *command, *next = buff;
1652 struct ftrace_func_command *p;
1655 func = strsep(&next, ":");
1658 ftrace_match_records(func, len, enable);
1664 command = strsep(&next, ":");
1666 mutex_lock(&ftrace_cmd_mutex);
1667 list_for_each_entry(p, &ftrace_commands, list) {
1668 if (strcmp(p->name, command) == 0) {
1669 ret = p->func(func, command, next, enable);
1674 mutex_unlock(&ftrace_cmd_mutex);
1680 ftrace_regex_write(struct file *file, const char __user *ubuf,
1681 size_t cnt, loff_t *ppos, int enable)
1683 struct ftrace_iterator *iter;
1688 if (!cnt || cnt < 0)
1691 mutex_lock(&ftrace_regex_lock);
1693 if (file->f_mode & FMODE_READ) {
1694 struct seq_file *m = file->private_data;
1697 iter = file->private_data;
1700 iter->flags &= ~FTRACE_ITER_CONT;
1701 iter->buffer_idx = 0;
1704 ret = get_user(ch, ubuf++);
1710 if (!(iter->flags & ~FTRACE_ITER_CONT)) {
1711 /* skip white space */
1712 while (cnt && isspace(ch)) {
1713 ret = get_user(ch, ubuf++);
1721 file->f_pos += read;
1726 iter->buffer_idx = 0;
1729 while (cnt && !isspace(ch)) {
1730 if (iter->buffer_idx < FTRACE_BUFF_MAX)
1731 iter->buffer[iter->buffer_idx++] = ch;
1736 ret = get_user(ch, ubuf++);
1745 iter->buffer[iter->buffer_idx] = 0;
1746 ret = ftrace_process_regex(iter->buffer,
1747 iter->buffer_idx, enable);
1750 iter->buffer_idx = 0;
1752 iter->flags |= FTRACE_ITER_CONT;
1755 file->f_pos += read;
1759 mutex_unlock(&ftrace_regex_lock);
1765 ftrace_filter_write(struct file *file, const char __user *ubuf,
1766 size_t cnt, loff_t *ppos)
1768 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
1772 ftrace_notrace_write(struct file *file, const char __user *ubuf,
1773 size_t cnt, loff_t *ppos)
1775 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
1779 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
1781 if (unlikely(ftrace_disabled))
1784 mutex_lock(&ftrace_regex_lock);
1786 ftrace_filter_reset(enable);
1788 ftrace_match_records(buf, len, enable);
1789 mutex_unlock(&ftrace_regex_lock);
1793 * ftrace_set_filter - set a function to filter on in ftrace
1794 * @buf - the string that holds the function filter text.
1795 * @len - the length of the string.
1796 * @reset - non zero to reset all filters before applying this filter.
1798 * Filters denote which functions should be enabled when tracing is enabled.
1799 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
1801 void ftrace_set_filter(unsigned char *buf, int len, int reset)
1803 ftrace_set_regex(buf, len, reset, 1);
1807 * ftrace_set_notrace - set a function to not trace in ftrace
1808 * @buf - the string that holds the function notrace text.
1809 * @len - the length of the string.
1810 * @reset - non zero to reset all filters before applying this filter.
1812 * Notrace Filters denote which functions should not be enabled when tracing
1813 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
1816 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
1818 ftrace_set_regex(buf, len, reset, 0);
1822 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
1824 struct seq_file *m = (struct seq_file *)file->private_data;
1825 struct ftrace_iterator *iter;
1827 mutex_lock(&ftrace_regex_lock);
1828 if (file->f_mode & FMODE_READ) {
1831 seq_release(inode, file);
1833 iter = file->private_data;
1835 if (iter->buffer_idx) {
1837 iter->buffer[iter->buffer_idx] = 0;
1838 ftrace_match_records(iter->buffer, iter->buffer_idx, enable);
1841 mutex_lock(&ftrace_lock);
1842 if (ftrace_start_up && ftrace_enabled)
1843 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
1844 mutex_unlock(&ftrace_lock);
1847 mutex_unlock(&ftrace_regex_lock);
1852 ftrace_filter_release(struct inode *inode, struct file *file)
1854 return ftrace_regex_release(inode, file, 1);
1858 ftrace_notrace_release(struct inode *inode, struct file *file)
1860 return ftrace_regex_release(inode, file, 0);
1863 static const struct file_operations ftrace_avail_fops = {
1864 .open = ftrace_avail_open,
1866 .llseek = seq_lseek,
1867 .release = ftrace_avail_release,
1870 static const struct file_operations ftrace_failures_fops = {
1871 .open = ftrace_failures_open,
1873 .llseek = seq_lseek,
1874 .release = ftrace_avail_release,
1877 static const struct file_operations ftrace_filter_fops = {
1878 .open = ftrace_filter_open,
1880 .write = ftrace_filter_write,
1881 .llseek = ftrace_regex_lseek,
1882 .release = ftrace_filter_release,
1885 static const struct file_operations ftrace_notrace_fops = {
1886 .open = ftrace_notrace_open,
1888 .write = ftrace_notrace_write,
1889 .llseek = ftrace_regex_lseek,
1890 .release = ftrace_notrace_release,
1893 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1895 static DEFINE_MUTEX(graph_lock);
1897 int ftrace_graph_count;
1898 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
1901 g_next(struct seq_file *m, void *v, loff_t *pos)
1903 unsigned long *array = m->private;
1908 if (index >= ftrace_graph_count)
1911 return &array[index];
1914 static void *g_start(struct seq_file *m, loff_t *pos)
1918 mutex_lock(&graph_lock);
1920 /* Nothing, tell g_show to print all functions are enabled */
1921 if (!ftrace_graph_count && !*pos)
1924 p = g_next(m, p, pos);
1929 static void g_stop(struct seq_file *m, void *p)
1931 mutex_unlock(&graph_lock);
1934 static int g_show(struct seq_file *m, void *v)
1936 unsigned long *ptr = v;
1937 char str[KSYM_SYMBOL_LEN];
1942 if (ptr == (unsigned long *)1) {
1943 seq_printf(m, "#### all functions enabled ####\n");
1947 kallsyms_lookup(*ptr, NULL, NULL, NULL, str);
1949 seq_printf(m, "%s\n", str);
1954 static struct seq_operations ftrace_graph_seq_ops = {
1962 ftrace_graph_open(struct inode *inode, struct file *file)
1966 if (unlikely(ftrace_disabled))
1969 mutex_lock(&graph_lock);
1970 if ((file->f_mode & FMODE_WRITE) &&
1971 !(file->f_flags & O_APPEND)) {
1972 ftrace_graph_count = 0;
1973 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
1976 if (file->f_mode & FMODE_READ) {
1977 ret = seq_open(file, &ftrace_graph_seq_ops);
1979 struct seq_file *m = file->private_data;
1980 m->private = ftrace_graph_funcs;
1983 file->private_data = ftrace_graph_funcs;
1984 mutex_unlock(&graph_lock);
1990 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
1992 struct dyn_ftrace *rec;
1993 struct ftrace_page *pg;
2001 if (ftrace_disabled)
2005 type = ftrace_setup_glob(buffer, strlen(buffer), &search, ¬);
2009 search_len = strlen(search);
2011 mutex_lock(&ftrace_lock);
2012 do_for_each_ftrace_rec(pg, rec) {
2014 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
2017 if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
2020 if (ftrace_match_record(rec, search, search_len, type)) {
2021 /* ensure it is not already in the array */
2023 for (i = 0; i < *idx; i++)
2024 if (array[i] == rec->ip) {
2029 array[(*idx)++] = rec->ip;
2033 } while_for_each_ftrace_rec();
2035 mutex_unlock(&ftrace_lock);
2037 return found ? 0 : -EINVAL;
2041 ftrace_graph_write(struct file *file, const char __user *ubuf,
2042 size_t cnt, loff_t *ppos)
2044 unsigned char buffer[FTRACE_BUFF_MAX+1];
2045 unsigned long *array;
2051 if (!cnt || cnt < 0)
2054 mutex_lock(&graph_lock);
2056 if (ftrace_graph_count >= FTRACE_GRAPH_MAX_FUNCS) {
2061 if (file->f_mode & FMODE_READ) {
2062 struct seq_file *m = file->private_data;
2065 array = file->private_data;
2067 ret = get_user(ch, ubuf++);
2073 /* skip white space */
2074 while (cnt && isspace(ch)) {
2075 ret = get_user(ch, ubuf++);
2088 while (cnt && !isspace(ch)) {
2089 if (index < FTRACE_BUFF_MAX)
2090 buffer[index++] = ch;
2095 ret = get_user(ch, ubuf++);
2103 /* we allow only one expression at a time */
2104 ret = ftrace_set_func(array, &ftrace_graph_count, buffer);
2108 file->f_pos += read;
2112 mutex_unlock(&graph_lock);
2117 static const struct file_operations ftrace_graph_fops = {
2118 .open = ftrace_graph_open,
2120 .write = ftrace_graph_write,
2122 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2124 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
2126 struct dentry *entry;
2128 entry = debugfs_create_file("available_filter_functions", 0444,
2129 d_tracer, NULL, &ftrace_avail_fops);
2131 pr_warning("Could not create debugfs "
2132 "'available_filter_functions' entry\n");
2134 entry = debugfs_create_file("failures", 0444,
2135 d_tracer, NULL, &ftrace_failures_fops);
2137 pr_warning("Could not create debugfs 'failures' entry\n");
2139 entry = debugfs_create_file("set_ftrace_filter", 0644, d_tracer,
2140 NULL, &ftrace_filter_fops);
2142 pr_warning("Could not create debugfs "
2143 "'set_ftrace_filter' entry\n");
2145 entry = debugfs_create_file("set_ftrace_notrace", 0644, d_tracer,
2146 NULL, &ftrace_notrace_fops);
2148 pr_warning("Could not create debugfs "
2149 "'set_ftrace_notrace' entry\n");
2151 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2152 entry = debugfs_create_file("set_graph_function", 0444, d_tracer,
2154 &ftrace_graph_fops);
2156 pr_warning("Could not create debugfs "
2157 "'set_graph_function' entry\n");
2158 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2163 static int ftrace_convert_nops(struct module *mod,
2164 unsigned long *start,
2169 unsigned long flags;
2171 mutex_lock(&ftrace_lock);
2174 addr = ftrace_call_adjust(*p++);
2176 * Some architecture linkers will pad between
2177 * the different mcount_loc sections of different
2178 * object files to satisfy alignments.
2179 * Skip any NULL pointers.
2183 ftrace_record_ip(addr);
2186 /* disable interrupts to prevent kstop machine */
2187 local_irq_save(flags);
2188 ftrace_update_code(mod);
2189 local_irq_restore(flags);
2190 mutex_unlock(&ftrace_lock);
2195 void ftrace_init_module(struct module *mod,
2196 unsigned long *start, unsigned long *end)
2198 if (ftrace_disabled || start == end)
2200 ftrace_convert_nops(mod, start, end);
2203 extern unsigned long __start_mcount_loc[];
2204 extern unsigned long __stop_mcount_loc[];
2206 void __init ftrace_init(void)
2208 unsigned long count, addr, flags;
2211 /* Keep the ftrace pointer to the stub */
2212 addr = (unsigned long)ftrace_stub;
2214 local_irq_save(flags);
2215 ftrace_dyn_arch_init(&addr);
2216 local_irq_restore(flags);
2218 /* ftrace_dyn_arch_init places the return code in addr */
2222 count = __stop_mcount_loc - __start_mcount_loc;
2224 ret = ftrace_dyn_table_alloc(count);
2228 last_ftrace_enabled = ftrace_enabled = 1;
2230 ret = ftrace_convert_nops(NULL,
2236 ftrace_disabled = 1;
2241 static int __init ftrace_nodyn_init(void)
2246 device_initcall(ftrace_nodyn_init);
2248 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
2249 static inline void ftrace_startup_enable(int command) { }
2250 /* Keep as macros so we do not need to define the commands */
2251 # define ftrace_startup(command) do { } while (0)
2252 # define ftrace_shutdown(command) do { } while (0)
2253 # define ftrace_startup_sysctl() do { } while (0)
2254 # define ftrace_shutdown_sysctl() do { } while (0)
2255 #endif /* CONFIG_DYNAMIC_FTRACE */
2258 ftrace_pid_read(struct file *file, char __user *ubuf,
2259 size_t cnt, loff_t *ppos)
2264 if (ftrace_pid_trace == ftrace_swapper_pid)
2265 r = sprintf(buf, "swapper tasks\n");
2266 else if (ftrace_pid_trace)
2267 r = sprintf(buf, "%u\n", pid_nr(ftrace_pid_trace));
2269 r = sprintf(buf, "no pid\n");
2271 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2274 static void clear_ftrace_swapper(void)
2276 struct task_struct *p;
2280 for_each_online_cpu(cpu) {
2282 clear_tsk_trace_trace(p);
2287 static void set_ftrace_swapper(void)
2289 struct task_struct *p;
2293 for_each_online_cpu(cpu) {
2295 set_tsk_trace_trace(p);
2300 static void clear_ftrace_pid(struct pid *pid)
2302 struct task_struct *p;
2305 do_each_pid_task(pid, PIDTYPE_PID, p) {
2306 clear_tsk_trace_trace(p);
2307 } while_each_pid_task(pid, PIDTYPE_PID, p);
2313 static void set_ftrace_pid(struct pid *pid)
2315 struct task_struct *p;
2318 do_each_pid_task(pid, PIDTYPE_PID, p) {
2319 set_tsk_trace_trace(p);
2320 } while_each_pid_task(pid, PIDTYPE_PID, p);
2324 static void clear_ftrace_pid_task(struct pid **pid)
2326 if (*pid == ftrace_swapper_pid)
2327 clear_ftrace_swapper();
2329 clear_ftrace_pid(*pid);
2334 static void set_ftrace_pid_task(struct pid *pid)
2336 if (pid == ftrace_swapper_pid)
2337 set_ftrace_swapper();
2339 set_ftrace_pid(pid);
2343 ftrace_pid_write(struct file *filp, const char __user *ubuf,
2344 size_t cnt, loff_t *ppos)
2351 if (cnt >= sizeof(buf))
2354 if (copy_from_user(&buf, ubuf, cnt))
2359 ret = strict_strtol(buf, 10, &val);
2363 mutex_lock(&ftrace_lock);
2365 /* disable pid tracing */
2366 if (!ftrace_pid_trace)
2369 clear_ftrace_pid_task(&ftrace_pid_trace);
2372 /* swapper task is special */
2374 pid = ftrace_swapper_pid;
2375 if (pid == ftrace_pid_trace)
2378 pid = find_get_pid(val);
2380 if (pid == ftrace_pid_trace) {
2386 if (ftrace_pid_trace)
2387 clear_ftrace_pid_task(&ftrace_pid_trace);
2392 ftrace_pid_trace = pid;
2394 set_ftrace_pid_task(ftrace_pid_trace);
2397 /* update the function call */
2398 ftrace_update_pid_func();
2399 ftrace_startup_enable(0);
2402 mutex_unlock(&ftrace_lock);
2407 static const struct file_operations ftrace_pid_fops = {
2408 .read = ftrace_pid_read,
2409 .write = ftrace_pid_write,
2412 static __init int ftrace_init_debugfs(void)
2414 struct dentry *d_tracer;
2415 struct dentry *entry;
2417 d_tracer = tracing_init_dentry();
2421 ftrace_init_dyn_debugfs(d_tracer);
2423 entry = debugfs_create_file("set_ftrace_pid", 0644, d_tracer,
2424 NULL, &ftrace_pid_fops);
2426 pr_warning("Could not create debugfs "
2427 "'set_ftrace_pid' entry\n");
2430 fs_initcall(ftrace_init_debugfs);
2433 * ftrace_kill - kill ftrace
2435 * This function should be used by panic code. It stops ftrace
2436 * but in a not so nice way. If you need to simply kill ftrace
2437 * from a non-atomic section, use ftrace_kill.
2439 void ftrace_kill(void)
2441 ftrace_disabled = 1;
2443 clear_ftrace_function();
2447 * register_ftrace_function - register a function for profiling
2448 * @ops - ops structure that holds the function for profiling.
2450 * Register a function to be called by all functions in the
2453 * Note: @ops->func and all the functions it calls must be labeled
2454 * with "notrace", otherwise it will go into a
2457 int register_ftrace_function(struct ftrace_ops *ops)
2461 if (unlikely(ftrace_disabled))
2464 mutex_lock(&ftrace_lock);
2466 ret = __register_ftrace_function(ops);
2469 mutex_unlock(&ftrace_lock);
2474 * unregister_ftrace_function - unregister a function for profiling.
2475 * @ops - ops structure that holds the function to unregister
2477 * Unregister a function that was added to be called by ftrace profiling.
2479 int unregister_ftrace_function(struct ftrace_ops *ops)
2483 mutex_lock(&ftrace_lock);
2484 ret = __unregister_ftrace_function(ops);
2486 mutex_unlock(&ftrace_lock);
2492 ftrace_enable_sysctl(struct ctl_table *table, int write,
2493 struct file *file, void __user *buffer, size_t *lenp,
2498 if (unlikely(ftrace_disabled))
2501 mutex_lock(&ftrace_lock);
2503 ret = proc_dointvec(table, write, file, buffer, lenp, ppos);
2505 if (ret || !write || (last_ftrace_enabled == ftrace_enabled))
2508 last_ftrace_enabled = ftrace_enabled;
2510 if (ftrace_enabled) {
2512 ftrace_startup_sysctl();
2514 /* we are starting ftrace again */
2515 if (ftrace_list != &ftrace_list_end) {
2516 if (ftrace_list->next == &ftrace_list_end)
2517 ftrace_trace_function = ftrace_list->func;
2519 ftrace_trace_function = ftrace_list_func;
2523 /* stopping ftrace calls (just send to ftrace_stub) */
2524 ftrace_trace_function = ftrace_stub;
2526 ftrace_shutdown_sysctl();
2530 mutex_unlock(&ftrace_lock);
2534 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2536 static atomic_t ftrace_graph_active;
2537 static struct notifier_block ftrace_suspend_notifier;
2539 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
2544 /* The callbacks that hook a function */
2545 trace_func_graph_ret_t ftrace_graph_return =
2546 (trace_func_graph_ret_t)ftrace_stub;
2547 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
2549 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
2550 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
2554 unsigned long flags;
2555 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
2556 struct task_struct *g, *t;
2558 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
2559 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
2560 * sizeof(struct ftrace_ret_stack),
2562 if (!ret_stack_list[i]) {
2570 read_lock_irqsave(&tasklist_lock, flags);
2571 do_each_thread(g, t) {
2577 if (t->ret_stack == NULL) {
2578 t->curr_ret_stack = -1;
2579 /* Make sure IRQs see the -1 first: */
2581 t->ret_stack = ret_stack_list[start++];
2582 atomic_set(&t->tracing_graph_pause, 0);
2583 atomic_set(&t->trace_overrun, 0);
2585 } while_each_thread(g, t);
2588 read_unlock_irqrestore(&tasklist_lock, flags);
2590 for (i = start; i < end; i++)
2591 kfree(ret_stack_list[i]);
2596 ftrace_graph_probe_sched_switch(struct rq *__rq, struct task_struct *prev,
2597 struct task_struct *next)
2599 unsigned long long timestamp;
2603 * Does the user want to count the time a function was asleep.
2604 * If so, do not update the time stamps.
2606 if (trace_flags & TRACE_ITER_SLEEP_TIME)
2609 timestamp = trace_clock_local();
2611 prev->ftrace_timestamp = timestamp;
2613 /* only process tasks that we timestamped */
2614 if (!next->ftrace_timestamp)
2618 * Update all the counters in next to make up for the
2619 * time next was sleeping.
2621 timestamp -= next->ftrace_timestamp;
2623 for (index = next->curr_ret_stack; index >= 0; index--)
2624 next->ret_stack[index].calltime += timestamp;
2627 /* Allocate a return stack for each task */
2628 static int start_graph_tracing(void)
2630 struct ftrace_ret_stack **ret_stack_list;
2633 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
2634 sizeof(struct ftrace_ret_stack *),
2637 if (!ret_stack_list)
2640 /* The cpu_boot init_task->ret_stack will never be freed */
2641 for_each_online_cpu(cpu)
2642 ftrace_graph_init_task(idle_task(cpu));
2645 ret = alloc_retstack_tasklist(ret_stack_list);
2646 } while (ret == -EAGAIN);
2649 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch);
2651 pr_info("ftrace_graph: Couldn't activate tracepoint"
2652 " probe to kernel_sched_switch\n");
2655 kfree(ret_stack_list);
2660 * Hibernation protection.
2661 * The state of the current task is too much unstable during
2662 * suspend/restore to disk. We want to protect against that.
2665 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
2669 case PM_HIBERNATION_PREPARE:
2670 pause_graph_tracing();
2673 case PM_POST_HIBERNATION:
2674 unpause_graph_tracing();
2680 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
2681 trace_func_graph_ent_t entryfunc)
2685 mutex_lock(&ftrace_lock);
2687 /* we currently allow only one tracer registered at a time */
2688 if (atomic_read(&ftrace_graph_active)) {
2693 ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
2694 register_pm_notifier(&ftrace_suspend_notifier);
2696 atomic_inc(&ftrace_graph_active);
2697 ret = start_graph_tracing();
2699 atomic_dec(&ftrace_graph_active);
2703 ftrace_graph_return = retfunc;
2704 ftrace_graph_entry = entryfunc;
2706 ftrace_startup(FTRACE_START_FUNC_RET);
2709 mutex_unlock(&ftrace_lock);
2713 void unregister_ftrace_graph(void)
2715 mutex_lock(&ftrace_lock);
2717 atomic_dec(&ftrace_graph_active);
2718 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch);
2719 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
2720 ftrace_graph_entry = ftrace_graph_entry_stub;
2721 ftrace_shutdown(FTRACE_STOP_FUNC_RET);
2722 unregister_pm_notifier(&ftrace_suspend_notifier);
2724 mutex_unlock(&ftrace_lock);
2727 /* Allocate a return stack for newly created task */
2728 void ftrace_graph_init_task(struct task_struct *t)
2730 if (atomic_read(&ftrace_graph_active)) {
2731 t->ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
2732 * sizeof(struct ftrace_ret_stack),
2736 t->curr_ret_stack = -1;
2737 atomic_set(&t->tracing_graph_pause, 0);
2738 atomic_set(&t->trace_overrun, 0);
2739 t->ftrace_timestamp = 0;
2741 t->ret_stack = NULL;
2744 void ftrace_graph_exit_task(struct task_struct *t)
2746 struct ftrace_ret_stack *ret_stack = t->ret_stack;
2748 t->ret_stack = NULL;
2749 /* NULL must become visible to IRQs before we free it: */
2755 void ftrace_graph_stop(void)