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/ftrace.h>
26 #include <linux/sysctl.h>
27 #include <linux/slab.h>
28 #include <linux/ctype.h>
29 #include <linux/list.h>
30 #include <linux/hash.h>
31 #include <linux/rcupdate.h>
33 #include <trace/events/sched.h>
35 #include <asm/ftrace.h>
36 #include <asm/setup.h>
38 #include "trace_output.h"
39 #include "trace_stat.h"
41 #define FTRACE_WARN_ON(cond) \
47 #define FTRACE_WARN_ON_ONCE(cond) \
49 if (WARN_ON_ONCE(cond)) \
53 /* hash bits for specific function selection */
54 #define FTRACE_HASH_BITS 7
55 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
57 /* ftrace_enabled is a method to turn ftrace on or off */
58 int ftrace_enabled __read_mostly;
59 static int last_ftrace_enabled;
61 /* Quick disabling of function tracer. */
62 int function_trace_stop;
64 /* List for set_ftrace_pid's pids. */
65 LIST_HEAD(ftrace_pids);
67 struct list_head list;
72 * ftrace_disabled is set when an anomaly is discovered.
73 * ftrace_disabled is much stronger than ftrace_enabled.
75 static int ftrace_disabled __read_mostly;
77 static DEFINE_MUTEX(ftrace_lock);
79 static struct ftrace_ops ftrace_list_end __read_mostly =
84 static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
85 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
86 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
87 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
90 * Traverse the ftrace_list, invoking all entries. The reason that we
91 * can use rcu_dereference_raw() is that elements removed from this list
92 * are simply leaked, so there is no need to interact with a grace-period
93 * mechanism. The rcu_dereference_raw() calls are needed to handle
94 * concurrent insertions into the ftrace_list.
96 * Silly Alpha and silly pointer-speculation compiler optimizations!
98 static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
100 struct ftrace_ops *op = rcu_dereference_raw(ftrace_list); /*see above*/
102 while (op != &ftrace_list_end) {
103 op->func(ip, parent_ip);
104 op = rcu_dereference_raw(op->next); /*see above*/
108 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
110 if (!test_tsk_trace_trace(current))
113 ftrace_pid_function(ip, parent_ip);
116 static void set_ftrace_pid_function(ftrace_func_t func)
118 /* do not set ftrace_pid_function to itself! */
119 if (func != ftrace_pid_func)
120 ftrace_pid_function = func;
124 * clear_ftrace_function - reset the ftrace function
126 * This NULLs the ftrace function and in essence stops
127 * tracing. There may be lag
129 void clear_ftrace_function(void)
131 ftrace_trace_function = ftrace_stub;
132 __ftrace_trace_function = ftrace_stub;
133 ftrace_pid_function = ftrace_stub;
136 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
138 * For those archs that do not test ftrace_trace_stop in their
139 * mcount call site, we need to do it from C.
141 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
143 if (function_trace_stop)
146 __ftrace_trace_function(ip, parent_ip);
150 static int __register_ftrace_function(struct ftrace_ops *ops)
152 ops->next = ftrace_list;
154 * We are entering ops into the ftrace_list but another
155 * CPU might be walking that list. We need to make sure
156 * the ops->next pointer is valid before another CPU sees
157 * the ops pointer included into the ftrace_list.
159 rcu_assign_pointer(ftrace_list, ops);
161 if (ftrace_enabled) {
164 if (ops->next == &ftrace_list_end)
167 func = ftrace_list_func;
169 if (!list_empty(&ftrace_pids)) {
170 set_ftrace_pid_function(func);
171 func = ftrace_pid_func;
175 * For one func, simply call it directly.
176 * For more than one func, call the chain.
178 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
179 ftrace_trace_function = func;
181 __ftrace_trace_function = func;
182 ftrace_trace_function = ftrace_test_stop_func;
189 static int __unregister_ftrace_function(struct ftrace_ops *ops)
191 struct ftrace_ops **p;
194 * If we are removing the last function, then simply point
195 * to the ftrace_stub.
197 if (ftrace_list == ops && ops->next == &ftrace_list_end) {
198 ftrace_trace_function = ftrace_stub;
199 ftrace_list = &ftrace_list_end;
203 for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
212 if (ftrace_enabled) {
213 /* If we only have one func left, then call that directly */
214 if (ftrace_list->next == &ftrace_list_end) {
215 ftrace_func_t func = ftrace_list->func;
217 if (!list_empty(&ftrace_pids)) {
218 set_ftrace_pid_function(func);
219 func = ftrace_pid_func;
221 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
222 ftrace_trace_function = func;
224 __ftrace_trace_function = func;
232 static void ftrace_update_pid_func(void)
236 if (ftrace_trace_function == ftrace_stub)
239 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
240 func = ftrace_trace_function;
242 func = __ftrace_trace_function;
245 if (!list_empty(&ftrace_pids)) {
246 set_ftrace_pid_function(func);
247 func = ftrace_pid_func;
249 if (func == ftrace_pid_func)
250 func = ftrace_pid_function;
253 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
254 ftrace_trace_function = func;
256 __ftrace_trace_function = func;
260 #ifdef CONFIG_FUNCTION_PROFILER
261 struct ftrace_profile {
262 struct hlist_node node;
264 unsigned long counter;
265 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
266 unsigned long long time;
267 unsigned long long time_squared;
271 struct ftrace_profile_page {
272 struct ftrace_profile_page *next;
274 struct ftrace_profile records[];
277 struct ftrace_profile_stat {
279 struct hlist_head *hash;
280 struct ftrace_profile_page *pages;
281 struct ftrace_profile_page *start;
282 struct tracer_stat stat;
285 #define PROFILE_RECORDS_SIZE \
286 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
288 #define PROFILES_PER_PAGE \
289 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
291 static int ftrace_profile_bits __read_mostly;
292 static int ftrace_profile_enabled __read_mostly;
294 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
295 static DEFINE_MUTEX(ftrace_profile_lock);
297 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
299 #define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
302 function_stat_next(void *v, int idx)
304 struct ftrace_profile *rec = v;
305 struct ftrace_profile_page *pg;
307 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
313 if ((void *)rec >= (void *)&pg->records[pg->index]) {
317 rec = &pg->records[0];
325 static void *function_stat_start(struct tracer_stat *trace)
327 struct ftrace_profile_stat *stat =
328 container_of(trace, struct ftrace_profile_stat, stat);
330 if (!stat || !stat->start)
333 return function_stat_next(&stat->start->records[0], 0);
336 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
337 /* function graph compares on total time */
338 static int function_stat_cmp(void *p1, void *p2)
340 struct ftrace_profile *a = p1;
341 struct ftrace_profile *b = p2;
343 if (a->time < b->time)
345 if (a->time > b->time)
351 /* not function graph compares against hits */
352 static int function_stat_cmp(void *p1, void *p2)
354 struct ftrace_profile *a = p1;
355 struct ftrace_profile *b = p2;
357 if (a->counter < b->counter)
359 if (a->counter > b->counter)
366 static int function_stat_headers(struct seq_file *m)
368 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
369 seq_printf(m, " Function "
372 "--- ---- --- ---\n");
374 seq_printf(m, " Function Hit\n"
380 static int function_stat_show(struct seq_file *m, void *v)
382 struct ftrace_profile *rec = v;
383 char str[KSYM_SYMBOL_LEN];
385 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
386 static struct trace_seq s;
387 unsigned long long avg;
388 unsigned long long stddev;
390 mutex_lock(&ftrace_profile_lock);
392 /* we raced with function_profile_reset() */
393 if (unlikely(rec->counter == 0)) {
398 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
399 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
401 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
404 do_div(avg, rec->counter);
406 /* Sample standard deviation (s^2) */
407 if (rec->counter <= 1)
410 stddev = rec->time_squared - rec->counter * avg * avg;
412 * Divide only 1000 for ns^2 -> us^2 conversion.
413 * trace_print_graph_duration will divide 1000 again.
415 do_div(stddev, (rec->counter - 1) * 1000);
419 trace_print_graph_duration(rec->time, &s);
420 trace_seq_puts(&s, " ");
421 trace_print_graph_duration(avg, &s);
422 trace_seq_puts(&s, " ");
423 trace_print_graph_duration(stddev, &s);
424 trace_print_seq(m, &s);
428 mutex_unlock(&ftrace_profile_lock);
433 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
435 struct ftrace_profile_page *pg;
437 pg = stat->pages = stat->start;
440 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
445 memset(stat->hash, 0,
446 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
449 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
451 struct ftrace_profile_page *pg;
456 /* If we already allocated, do nothing */
460 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
464 #ifdef CONFIG_DYNAMIC_FTRACE
465 functions = ftrace_update_tot_cnt;
468 * We do not know the number of functions that exist because
469 * dynamic tracing is what counts them. With past experience
470 * we have around 20K functions. That should be more than enough.
471 * It is highly unlikely we will execute every function in
477 pg = stat->start = stat->pages;
479 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
481 for (i = 0; i < pages; i++) {
482 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
493 unsigned long tmp = (unsigned long)pg;
499 free_page((unsigned long)stat->pages);
506 static int ftrace_profile_init_cpu(int cpu)
508 struct ftrace_profile_stat *stat;
511 stat = &per_cpu(ftrace_profile_stats, cpu);
514 /* If the profile is already created, simply reset it */
515 ftrace_profile_reset(stat);
520 * We are profiling all functions, but usually only a few thousand
521 * functions are hit. We'll make a hash of 1024 items.
523 size = FTRACE_PROFILE_HASH_SIZE;
525 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
530 if (!ftrace_profile_bits) {
533 for (; size; size >>= 1)
534 ftrace_profile_bits++;
537 /* Preallocate the function profiling pages */
538 if (ftrace_profile_pages_init(stat) < 0) {
547 static int ftrace_profile_init(void)
552 for_each_online_cpu(cpu) {
553 ret = ftrace_profile_init_cpu(cpu);
561 /* interrupts must be disabled */
562 static struct ftrace_profile *
563 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
565 struct ftrace_profile *rec;
566 struct hlist_head *hhd;
567 struct hlist_node *n;
570 key = hash_long(ip, ftrace_profile_bits);
571 hhd = &stat->hash[key];
573 if (hlist_empty(hhd))
576 hlist_for_each_entry_rcu(rec, n, hhd, node) {
584 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
585 struct ftrace_profile *rec)
589 key = hash_long(rec->ip, ftrace_profile_bits);
590 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
594 * The memory is already allocated, this simply finds a new record to use.
596 static struct ftrace_profile *
597 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
599 struct ftrace_profile *rec = NULL;
601 /* prevent recursion (from NMIs) */
602 if (atomic_inc_return(&stat->disabled) != 1)
606 * Try to find the function again since an NMI
607 * could have added it
609 rec = ftrace_find_profiled_func(stat, ip);
613 if (stat->pages->index == PROFILES_PER_PAGE) {
614 if (!stat->pages->next)
616 stat->pages = stat->pages->next;
619 rec = &stat->pages->records[stat->pages->index++];
621 ftrace_add_profile(stat, rec);
624 atomic_dec(&stat->disabled);
630 function_profile_call(unsigned long ip, unsigned long parent_ip)
632 struct ftrace_profile_stat *stat;
633 struct ftrace_profile *rec;
636 if (!ftrace_profile_enabled)
639 local_irq_save(flags);
641 stat = &__get_cpu_var(ftrace_profile_stats);
642 if (!stat->hash || !ftrace_profile_enabled)
645 rec = ftrace_find_profiled_func(stat, ip);
647 rec = ftrace_profile_alloc(stat, ip);
654 local_irq_restore(flags);
657 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
658 static int profile_graph_entry(struct ftrace_graph_ent *trace)
660 function_profile_call(trace->func, 0);
664 static void profile_graph_return(struct ftrace_graph_ret *trace)
666 struct ftrace_profile_stat *stat;
667 unsigned long long calltime;
668 struct ftrace_profile *rec;
671 local_irq_save(flags);
672 stat = &__get_cpu_var(ftrace_profile_stats);
673 if (!stat->hash || !ftrace_profile_enabled)
676 /* If the calltime was zero'd ignore it */
677 if (!trace->calltime)
680 calltime = trace->rettime - trace->calltime;
682 if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
685 index = trace->depth;
687 /* Append this call time to the parent time to subtract */
689 current->ret_stack[index - 1].subtime += calltime;
691 if (current->ret_stack[index].subtime < calltime)
692 calltime -= current->ret_stack[index].subtime;
697 rec = ftrace_find_profiled_func(stat, trace->func);
699 rec->time += calltime;
700 rec->time_squared += calltime * calltime;
704 local_irq_restore(flags);
707 static int register_ftrace_profiler(void)
709 return register_ftrace_graph(&profile_graph_return,
710 &profile_graph_entry);
713 static void unregister_ftrace_profiler(void)
715 unregister_ftrace_graph();
718 static struct ftrace_ops ftrace_profile_ops __read_mostly =
720 .func = function_profile_call,
723 static int register_ftrace_profiler(void)
725 return register_ftrace_function(&ftrace_profile_ops);
728 static void unregister_ftrace_profiler(void)
730 unregister_ftrace_function(&ftrace_profile_ops);
732 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
735 ftrace_profile_write(struct file *filp, const char __user *ubuf,
736 size_t cnt, loff_t *ppos)
739 char buf[64]; /* big enough to hold a number */
742 if (cnt >= sizeof(buf))
745 if (copy_from_user(&buf, ubuf, cnt))
750 ret = strict_strtoul(buf, 10, &val);
756 mutex_lock(&ftrace_profile_lock);
757 if (ftrace_profile_enabled ^ val) {
759 ret = ftrace_profile_init();
765 ret = register_ftrace_profiler();
770 ftrace_profile_enabled = 1;
772 ftrace_profile_enabled = 0;
774 * unregister_ftrace_profiler calls stop_machine
775 * so this acts like an synchronize_sched.
777 unregister_ftrace_profiler();
781 mutex_unlock(&ftrace_profile_lock);
789 ftrace_profile_read(struct file *filp, char __user *ubuf,
790 size_t cnt, loff_t *ppos)
792 char buf[64]; /* big enough to hold a number */
795 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
796 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
799 static const struct file_operations ftrace_profile_fops = {
800 .open = tracing_open_generic,
801 .read = ftrace_profile_read,
802 .write = ftrace_profile_write,
803 .llseek = default_llseek,
806 /* used to initialize the real stat files */
807 static struct tracer_stat function_stats __initdata = {
809 .stat_start = function_stat_start,
810 .stat_next = function_stat_next,
811 .stat_cmp = function_stat_cmp,
812 .stat_headers = function_stat_headers,
813 .stat_show = function_stat_show
816 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
818 struct ftrace_profile_stat *stat;
819 struct dentry *entry;
824 for_each_possible_cpu(cpu) {
825 stat = &per_cpu(ftrace_profile_stats, cpu);
827 /* allocate enough for function name + cpu number */
828 name = kmalloc(32, GFP_KERNEL);
831 * The files created are permanent, if something happens
832 * we still do not free memory.
835 "Could not allocate stat file for cpu %d\n",
839 stat->stat = function_stats;
840 snprintf(name, 32, "function%d", cpu);
841 stat->stat.name = name;
842 ret = register_stat_tracer(&stat->stat);
845 "Could not register function stat for cpu %d\n",
852 entry = debugfs_create_file("function_profile_enabled", 0644,
853 d_tracer, NULL, &ftrace_profile_fops);
855 pr_warning("Could not create debugfs "
856 "'function_profile_enabled' entry\n");
859 #else /* CONFIG_FUNCTION_PROFILER */
860 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
863 #endif /* CONFIG_FUNCTION_PROFILER */
865 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
867 #ifdef CONFIG_DYNAMIC_FTRACE
869 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
870 # error Dynamic ftrace depends on MCOUNT_RECORD
873 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
875 struct ftrace_func_probe {
876 struct hlist_node node;
877 struct ftrace_probe_ops *ops;
885 FTRACE_ENABLE_CALLS = (1 << 0),
886 FTRACE_DISABLE_CALLS = (1 << 1),
887 FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
888 FTRACE_START_FUNC_RET = (1 << 3),
889 FTRACE_STOP_FUNC_RET = (1 << 4),
892 static int ftrace_filtered;
894 static struct dyn_ftrace *ftrace_new_addrs;
896 static DEFINE_MUTEX(ftrace_regex_lock);
899 struct ftrace_page *next;
901 struct dyn_ftrace records[];
904 #define ENTRIES_PER_PAGE \
905 ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
907 /* estimate from running different kernels */
908 #define NR_TO_INIT 10000
910 static struct ftrace_page *ftrace_pages_start;
911 static struct ftrace_page *ftrace_pages;
913 static struct dyn_ftrace *ftrace_free_records;
916 * This is a double for. Do not use 'break' to break out of the loop,
917 * you must use a goto.
919 #define do_for_each_ftrace_rec(pg, rec) \
920 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
922 for (_____i = 0; _____i < pg->index; _____i++) { \
923 rec = &pg->records[_____i];
925 #define while_for_each_ftrace_rec() \
929 static void ftrace_free_rec(struct dyn_ftrace *rec)
931 rec->freelist = ftrace_free_records;
932 ftrace_free_records = rec;
933 rec->flags |= FTRACE_FL_FREE;
936 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
938 struct dyn_ftrace *rec;
940 /* First check for freed records */
941 if (ftrace_free_records) {
942 rec = ftrace_free_records;
944 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
945 FTRACE_WARN_ON_ONCE(1);
946 ftrace_free_records = NULL;
950 ftrace_free_records = rec->freelist;
951 memset(rec, 0, sizeof(*rec));
955 if (ftrace_pages->index == ENTRIES_PER_PAGE) {
956 if (!ftrace_pages->next) {
957 /* allocate another page */
959 (void *)get_zeroed_page(GFP_KERNEL);
960 if (!ftrace_pages->next)
963 ftrace_pages = ftrace_pages->next;
966 return &ftrace_pages->records[ftrace_pages->index++];
969 static struct dyn_ftrace *
970 ftrace_record_ip(unsigned long ip)
972 struct dyn_ftrace *rec;
977 rec = ftrace_alloc_dyn_node(ip);
982 rec->newlist = ftrace_new_addrs;
983 ftrace_new_addrs = rec;
988 static void print_ip_ins(const char *fmt, unsigned char *p)
992 printk(KERN_CONT "%s", fmt);
994 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
995 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
998 static void ftrace_bug(int failed, unsigned long ip)
1002 FTRACE_WARN_ON_ONCE(1);
1003 pr_info("ftrace faulted on modifying ");
1007 FTRACE_WARN_ON_ONCE(1);
1008 pr_info("ftrace failed to modify ");
1010 print_ip_ins(" actual: ", (unsigned char *)ip);
1011 printk(KERN_CONT "\n");
1014 FTRACE_WARN_ON_ONCE(1);
1015 pr_info("ftrace faulted on writing ");
1019 FTRACE_WARN_ON_ONCE(1);
1020 pr_info("ftrace faulted on unknown error ");
1026 /* Return 1 if the address range is reserved for ftrace */
1027 int ftrace_text_reserved(void *start, void *end)
1029 struct dyn_ftrace *rec;
1030 struct ftrace_page *pg;
1032 do_for_each_ftrace_rec(pg, rec) {
1033 if (rec->ip <= (unsigned long)end &&
1034 rec->ip + MCOUNT_INSN_SIZE > (unsigned long)start)
1036 } while_for_each_ftrace_rec();
1042 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1044 unsigned long ftrace_addr;
1045 unsigned long flag = 0UL;
1047 ftrace_addr = (unsigned long)FTRACE_ADDR;
1050 * If this record is not to be traced or we want to disable it,
1053 * If we want to enable it and filtering is off, then enable it.
1055 * If we want to enable it and filtering is on, enable it only if
1058 if (enable && !(rec->flags & FTRACE_FL_NOTRACE)) {
1059 if (!ftrace_filtered || (rec->flags & FTRACE_FL_FILTER))
1060 flag = FTRACE_FL_ENABLED;
1063 /* If the state of this record hasn't changed, then do nothing */
1064 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1068 rec->flags |= FTRACE_FL_ENABLED;
1069 return ftrace_make_call(rec, ftrace_addr);
1072 rec->flags &= ~FTRACE_FL_ENABLED;
1073 return ftrace_make_nop(NULL, rec, ftrace_addr);
1076 static void ftrace_replace_code(int enable)
1078 struct dyn_ftrace *rec;
1079 struct ftrace_page *pg;
1082 do_for_each_ftrace_rec(pg, rec) {
1084 * Skip over free records, records that have
1085 * failed and not converted.
1087 if (rec->flags & FTRACE_FL_FREE ||
1088 rec->flags & FTRACE_FL_FAILED ||
1089 !(rec->flags & FTRACE_FL_CONVERTED))
1092 failed = __ftrace_replace_code(rec, enable);
1094 rec->flags |= FTRACE_FL_FAILED;
1095 ftrace_bug(failed, rec->ip);
1096 /* Stop processing */
1099 } while_for_each_ftrace_rec();
1103 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1110 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1112 ftrace_bug(ret, ip);
1113 rec->flags |= FTRACE_FL_FAILED;
1120 * archs can override this function if they must do something
1121 * before the modifying code is performed.
1123 int __weak ftrace_arch_code_modify_prepare(void)
1129 * archs can override this function if they must do something
1130 * after the modifying code is performed.
1132 int __weak ftrace_arch_code_modify_post_process(void)
1137 static int __ftrace_modify_code(void *data)
1139 int *command = data;
1141 if (*command & FTRACE_ENABLE_CALLS)
1142 ftrace_replace_code(1);
1143 else if (*command & FTRACE_DISABLE_CALLS)
1144 ftrace_replace_code(0);
1146 if (*command & FTRACE_UPDATE_TRACE_FUNC)
1147 ftrace_update_ftrace_func(ftrace_trace_function);
1149 if (*command & FTRACE_START_FUNC_RET)
1150 ftrace_enable_ftrace_graph_caller();
1151 else if (*command & FTRACE_STOP_FUNC_RET)
1152 ftrace_disable_ftrace_graph_caller();
1157 static void ftrace_run_update_code(int command)
1161 ret = ftrace_arch_code_modify_prepare();
1162 FTRACE_WARN_ON(ret);
1166 stop_machine(__ftrace_modify_code, &command, NULL);
1168 ret = ftrace_arch_code_modify_post_process();
1169 FTRACE_WARN_ON(ret);
1172 static ftrace_func_t saved_ftrace_func;
1173 static int ftrace_start_up;
1175 static void ftrace_startup_enable(int command)
1177 if (saved_ftrace_func != ftrace_trace_function) {
1178 saved_ftrace_func = ftrace_trace_function;
1179 command |= FTRACE_UPDATE_TRACE_FUNC;
1182 if (!command || !ftrace_enabled)
1185 ftrace_run_update_code(command);
1188 static void ftrace_startup(int command)
1190 if (unlikely(ftrace_disabled))
1194 command |= FTRACE_ENABLE_CALLS;
1196 ftrace_startup_enable(command);
1199 static void ftrace_shutdown(int command)
1201 if (unlikely(ftrace_disabled))
1206 * Just warn in case of unbalance, no need to kill ftrace, it's not
1207 * critical but the ftrace_call callers may be never nopped again after
1208 * further ftrace uses.
1210 WARN_ON_ONCE(ftrace_start_up < 0);
1212 if (!ftrace_start_up)
1213 command |= FTRACE_DISABLE_CALLS;
1215 if (saved_ftrace_func != ftrace_trace_function) {
1216 saved_ftrace_func = ftrace_trace_function;
1217 command |= FTRACE_UPDATE_TRACE_FUNC;
1220 if (!command || !ftrace_enabled)
1223 ftrace_run_update_code(command);
1226 static void ftrace_startup_sysctl(void)
1228 if (unlikely(ftrace_disabled))
1231 /* Force update next time */
1232 saved_ftrace_func = NULL;
1233 /* ftrace_start_up is true if we want ftrace running */
1234 if (ftrace_start_up)
1235 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
1238 static void ftrace_shutdown_sysctl(void)
1240 if (unlikely(ftrace_disabled))
1243 /* ftrace_start_up is true if ftrace is running */
1244 if (ftrace_start_up)
1245 ftrace_run_update_code(FTRACE_DISABLE_CALLS);
1248 static cycle_t ftrace_update_time;
1249 static unsigned long ftrace_update_cnt;
1250 unsigned long ftrace_update_tot_cnt;
1252 static int ftrace_update_code(struct module *mod)
1254 struct dyn_ftrace *p;
1255 cycle_t start, stop;
1257 start = ftrace_now(raw_smp_processor_id());
1258 ftrace_update_cnt = 0;
1260 while (ftrace_new_addrs) {
1262 /* If something went wrong, bail without enabling anything */
1263 if (unlikely(ftrace_disabled))
1266 p = ftrace_new_addrs;
1267 ftrace_new_addrs = p->newlist;
1271 * Do the initial record convertion from mcount jump
1272 * to the NOP instructions.
1274 if (!ftrace_code_disable(mod, p)) {
1279 p->flags |= FTRACE_FL_CONVERTED;
1280 ftrace_update_cnt++;
1283 * If the tracing is enabled, go ahead and enable the record.
1285 * The reason not to enable the record immediatelly is the
1286 * inherent check of ftrace_make_nop/ftrace_make_call for
1287 * correct previous instructions. Making first the NOP
1288 * conversion puts the module to the correct state, thus
1289 * passing the ftrace_make_call check.
1291 if (ftrace_start_up) {
1292 int failed = __ftrace_replace_code(p, 1);
1294 ftrace_bug(failed, p->ip);
1300 stop = ftrace_now(raw_smp_processor_id());
1301 ftrace_update_time = stop - start;
1302 ftrace_update_tot_cnt += ftrace_update_cnt;
1307 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
1309 struct ftrace_page *pg;
1313 /* allocate a few pages */
1314 ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
1315 if (!ftrace_pages_start)
1319 * Allocate a few more pages.
1321 * TODO: have some parser search vmlinux before
1322 * final linking to find all calls to ftrace.
1324 * a) know how many pages to allocate.
1326 * b) set up the table then.
1328 * The dynamic code is still necessary for
1332 pg = ftrace_pages = ftrace_pages_start;
1334 cnt = num_to_init / ENTRIES_PER_PAGE;
1335 pr_info("ftrace: allocating %ld entries in %d pages\n",
1336 num_to_init, cnt + 1);
1338 for (i = 0; i < cnt; i++) {
1339 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
1341 /* If we fail, we'll try later anyway */
1352 FTRACE_ITER_FILTER = (1 << 0),
1353 FTRACE_ITER_NOTRACE = (1 << 1),
1354 FTRACE_ITER_FAILURES = (1 << 2),
1355 FTRACE_ITER_PRINTALL = (1 << 3),
1356 FTRACE_ITER_HASH = (1 << 4),
1359 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
1361 struct ftrace_iterator {
1364 struct ftrace_page *pg;
1365 struct dyn_ftrace *func;
1366 struct ftrace_func_probe *probe;
1367 struct trace_parser parser;
1374 t_hash_next(struct seq_file *m, loff_t *pos)
1376 struct ftrace_iterator *iter = m->private;
1377 struct hlist_node *hnd = NULL;
1378 struct hlist_head *hhd;
1384 hnd = &iter->probe->node;
1386 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
1389 hhd = &ftrace_func_hash[iter->hidx];
1391 if (hlist_empty(hhd)) {
1407 if (WARN_ON_ONCE(!hnd))
1410 iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
1415 static void *t_hash_start(struct seq_file *m, loff_t *pos)
1417 struct ftrace_iterator *iter = m->private;
1421 if (iter->func_pos > *pos)
1425 for (l = 0; l <= (*pos - iter->func_pos); ) {
1426 p = t_hash_next(m, &l);
1433 /* Only set this if we have an item */
1434 iter->flags |= FTRACE_ITER_HASH;
1440 t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
1442 struct ftrace_func_probe *rec;
1445 if (WARN_ON_ONCE(!rec))
1448 if (rec->ops->print)
1449 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
1451 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
1454 seq_printf(m, ":%p", rec->data);
1461 t_next(struct seq_file *m, void *v, loff_t *pos)
1463 struct ftrace_iterator *iter = m->private;
1464 struct dyn_ftrace *rec = NULL;
1466 if (iter->flags & FTRACE_ITER_HASH)
1467 return t_hash_next(m, pos);
1470 iter->pos = iter->func_pos = *pos;
1472 if (iter->flags & FTRACE_ITER_PRINTALL)
1473 return t_hash_start(m, pos);
1476 if (iter->idx >= iter->pg->index) {
1477 if (iter->pg->next) {
1478 iter->pg = iter->pg->next;
1483 rec = &iter->pg->records[iter->idx++];
1484 if ((rec->flags & FTRACE_FL_FREE) ||
1486 (!(iter->flags & FTRACE_ITER_FAILURES) &&
1487 (rec->flags & FTRACE_FL_FAILED)) ||
1489 ((iter->flags & FTRACE_ITER_FAILURES) &&
1490 !(rec->flags & FTRACE_FL_FAILED)) ||
1492 ((iter->flags & FTRACE_ITER_FILTER) &&
1493 !(rec->flags & FTRACE_FL_FILTER)) ||
1495 ((iter->flags & FTRACE_ITER_NOTRACE) &&
1496 !(rec->flags & FTRACE_FL_NOTRACE))) {
1503 return t_hash_start(m, pos);
1510 static void reset_iter_read(struct ftrace_iterator *iter)
1514 iter->flags &= ~(FTRACE_ITER_PRINTALL & FTRACE_ITER_HASH);
1517 static void *t_start(struct seq_file *m, loff_t *pos)
1519 struct ftrace_iterator *iter = m->private;
1523 mutex_lock(&ftrace_lock);
1525 * If an lseek was done, then reset and start from beginning.
1527 if (*pos < iter->pos)
1528 reset_iter_read(iter);
1531 * For set_ftrace_filter reading, if we have the filter
1532 * off, we can short cut and just print out that all
1533 * functions are enabled.
1535 if (iter->flags & FTRACE_ITER_FILTER && !ftrace_filtered) {
1537 return t_hash_start(m, pos);
1538 iter->flags |= FTRACE_ITER_PRINTALL;
1539 /* reset in case of seek/pread */
1540 iter->flags &= ~FTRACE_ITER_HASH;
1544 if (iter->flags & FTRACE_ITER_HASH)
1545 return t_hash_start(m, pos);
1548 * Unfortunately, we need to restart at ftrace_pages_start
1549 * every time we let go of the ftrace_mutex. This is because
1550 * those pointers can change without the lock.
1552 iter->pg = ftrace_pages_start;
1554 for (l = 0; l <= *pos; ) {
1555 p = t_next(m, p, &l);
1561 if (iter->flags & FTRACE_ITER_FILTER)
1562 return t_hash_start(m, pos);
1570 static void t_stop(struct seq_file *m, void *p)
1572 mutex_unlock(&ftrace_lock);
1575 static int t_show(struct seq_file *m, void *v)
1577 struct ftrace_iterator *iter = m->private;
1578 struct dyn_ftrace *rec;
1580 if (iter->flags & FTRACE_ITER_HASH)
1581 return t_hash_show(m, iter);
1583 if (iter->flags & FTRACE_ITER_PRINTALL) {
1584 seq_printf(m, "#### all functions enabled ####\n");
1593 seq_printf(m, "%ps\n", (void *)rec->ip);
1598 static const struct seq_operations show_ftrace_seq_ops = {
1606 ftrace_avail_open(struct inode *inode, struct file *file)
1608 struct ftrace_iterator *iter;
1611 if (unlikely(ftrace_disabled))
1614 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1618 iter->pg = ftrace_pages_start;
1620 ret = seq_open(file, &show_ftrace_seq_ops);
1622 struct seq_file *m = file->private_data;
1633 ftrace_failures_open(struct inode *inode, struct file *file)
1637 struct ftrace_iterator *iter;
1639 ret = ftrace_avail_open(inode, file);
1641 m = file->private_data;
1643 iter->flags = FTRACE_ITER_FAILURES;
1650 static void ftrace_filter_reset(int enable)
1652 struct ftrace_page *pg;
1653 struct dyn_ftrace *rec;
1654 unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1656 mutex_lock(&ftrace_lock);
1658 ftrace_filtered = 0;
1659 do_for_each_ftrace_rec(pg, rec) {
1660 if (rec->flags & FTRACE_FL_FAILED)
1662 rec->flags &= ~type;
1663 } while_for_each_ftrace_rec();
1664 mutex_unlock(&ftrace_lock);
1668 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
1670 struct ftrace_iterator *iter;
1673 if (unlikely(ftrace_disabled))
1676 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1680 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
1685 mutex_lock(&ftrace_regex_lock);
1686 if ((file->f_mode & FMODE_WRITE) &&
1687 (file->f_flags & O_TRUNC))
1688 ftrace_filter_reset(enable);
1690 if (file->f_mode & FMODE_READ) {
1691 iter->pg = ftrace_pages_start;
1692 iter->flags = enable ? FTRACE_ITER_FILTER :
1693 FTRACE_ITER_NOTRACE;
1695 ret = seq_open(file, &show_ftrace_seq_ops);
1697 struct seq_file *m = file->private_data;
1700 trace_parser_put(&iter->parser);
1704 file->private_data = iter;
1705 mutex_unlock(&ftrace_regex_lock);
1711 ftrace_filter_open(struct inode *inode, struct file *file)
1713 return ftrace_regex_open(inode, file, 1);
1717 ftrace_notrace_open(struct inode *inode, struct file *file)
1719 return ftrace_regex_open(inode, file, 0);
1723 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1727 if (file->f_mode & FMODE_READ)
1728 ret = seq_lseek(file, offset, origin);
1730 file->f_pos = ret = 1;
1735 static int ftrace_match(char *str, char *regex, int len, int type)
1742 if (strcmp(str, regex) == 0)
1745 case MATCH_FRONT_ONLY:
1746 if (strncmp(str, regex, len) == 0)
1749 case MATCH_MIDDLE_ONLY:
1750 if (strstr(str, regex))
1753 case MATCH_END_ONLY:
1755 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
1764 ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
1766 char str[KSYM_SYMBOL_LEN];
1768 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1769 return ftrace_match(str, regex, len, type);
1772 static int ftrace_match_records(char *buff, int len, int enable)
1774 unsigned int search_len;
1775 struct ftrace_page *pg;
1776 struct dyn_ftrace *rec;
1783 flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1784 type = filter_parse_regex(buff, len, &search, ¬);
1786 search_len = strlen(search);
1788 mutex_lock(&ftrace_lock);
1789 do_for_each_ftrace_rec(pg, rec) {
1791 if (rec->flags & FTRACE_FL_FAILED)
1794 if (ftrace_match_record(rec, search, search_len, type)) {
1796 rec->flags &= ~flag;
1802 * Only enable filtering if we have a function that
1805 if (enable && (rec->flags & FTRACE_FL_FILTER))
1806 ftrace_filtered = 1;
1807 } while_for_each_ftrace_rec();
1808 mutex_unlock(&ftrace_lock);
1814 ftrace_match_module_record(struct dyn_ftrace *rec, char *mod,
1815 char *regex, int len, int type)
1817 char str[KSYM_SYMBOL_LEN];
1820 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
1822 if (!modname || strcmp(modname, mod))
1825 /* blank search means to match all funcs in the mod */
1827 return ftrace_match(str, regex, len, type);
1832 static int ftrace_match_module_records(char *buff, char *mod, int enable)
1834 unsigned search_len = 0;
1835 struct ftrace_page *pg;
1836 struct dyn_ftrace *rec;
1837 int type = MATCH_FULL;
1838 char *search = buff;
1843 flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1845 /* blank or '*' mean the same */
1846 if (strcmp(buff, "*") == 0)
1849 /* handle the case of 'dont filter this module' */
1850 if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
1856 type = filter_parse_regex(buff, strlen(buff), &search, ¬);
1857 search_len = strlen(search);
1860 mutex_lock(&ftrace_lock);
1861 do_for_each_ftrace_rec(pg, rec) {
1863 if (rec->flags & FTRACE_FL_FAILED)
1866 if (ftrace_match_module_record(rec, mod,
1867 search, search_len, type)) {
1869 rec->flags &= ~flag;
1874 if (enable && (rec->flags & FTRACE_FL_FILTER))
1875 ftrace_filtered = 1;
1877 } while_for_each_ftrace_rec();
1878 mutex_unlock(&ftrace_lock);
1884 * We register the module command as a template to show others how
1885 * to register the a command as well.
1889 ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
1894 * cmd == 'mod' because we only registered this func
1895 * for the 'mod' ftrace_func_command.
1896 * But if you register one func with multiple commands,
1897 * you can tell which command was used by the cmd
1901 /* we must have a module name */
1905 mod = strsep(¶m, ":");
1909 if (ftrace_match_module_records(func, mod, enable))
1914 static struct ftrace_func_command ftrace_mod_cmd = {
1916 .func = ftrace_mod_callback,
1919 static int __init ftrace_mod_cmd_init(void)
1921 return register_ftrace_command(&ftrace_mod_cmd);
1923 device_initcall(ftrace_mod_cmd_init);
1926 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
1928 struct ftrace_func_probe *entry;
1929 struct hlist_head *hhd;
1930 struct hlist_node *n;
1933 key = hash_long(ip, FTRACE_HASH_BITS);
1935 hhd = &ftrace_func_hash[key];
1937 if (hlist_empty(hhd))
1941 * Disable preemption for these calls to prevent a RCU grace
1942 * period. This syncs the hash iteration and freeing of items
1943 * on the hash. rcu_read_lock is too dangerous here.
1945 preempt_disable_notrace();
1946 hlist_for_each_entry_rcu(entry, n, hhd, node) {
1947 if (entry->ip == ip)
1948 entry->ops->func(ip, parent_ip, &entry->data);
1950 preempt_enable_notrace();
1953 static struct ftrace_ops trace_probe_ops __read_mostly =
1955 .func = function_trace_probe_call,
1958 static int ftrace_probe_registered;
1960 static void __enable_ftrace_function_probe(void)
1964 if (ftrace_probe_registered)
1967 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1968 struct hlist_head *hhd = &ftrace_func_hash[i];
1972 /* Nothing registered? */
1973 if (i == FTRACE_FUNC_HASHSIZE)
1976 __register_ftrace_function(&trace_probe_ops);
1978 ftrace_probe_registered = 1;
1981 static void __disable_ftrace_function_probe(void)
1985 if (!ftrace_probe_registered)
1988 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1989 struct hlist_head *hhd = &ftrace_func_hash[i];
1994 /* no more funcs left */
1995 __unregister_ftrace_function(&trace_probe_ops);
1997 ftrace_probe_registered = 0;
2001 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
2003 struct ftrace_func_probe *entry =
2004 container_of(rhp, struct ftrace_func_probe, rcu);
2006 if (entry->ops->free)
2007 entry->ops->free(&entry->data);
2013 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2016 struct ftrace_func_probe *entry;
2017 struct ftrace_page *pg;
2018 struct dyn_ftrace *rec;
2024 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
2025 len = strlen(search);
2027 /* we do not support '!' for function probes */
2031 mutex_lock(&ftrace_lock);
2032 do_for_each_ftrace_rec(pg, rec) {
2034 if (rec->flags & FTRACE_FL_FAILED)
2037 if (!ftrace_match_record(rec, search, len, type))
2040 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2042 /* If we did not process any, then return error */
2053 * The caller might want to do something special
2054 * for each function we find. We call the callback
2055 * to give the caller an opportunity to do so.
2057 if (ops->callback) {
2058 if (ops->callback(rec->ip, &entry->data) < 0) {
2059 /* caller does not like this func */
2066 entry->ip = rec->ip;
2068 key = hash_long(entry->ip, FTRACE_HASH_BITS);
2069 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
2071 } while_for_each_ftrace_rec();
2072 __enable_ftrace_function_probe();
2075 mutex_unlock(&ftrace_lock);
2081 PROBE_TEST_FUNC = 1,
2086 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2087 void *data, int flags)
2089 struct ftrace_func_probe *entry;
2090 struct hlist_node *n, *tmp;
2091 char str[KSYM_SYMBOL_LEN];
2092 int type = MATCH_FULL;
2096 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
2101 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
2102 len = strlen(search);
2104 /* we do not support '!' for function probes */
2109 mutex_lock(&ftrace_lock);
2110 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2111 struct hlist_head *hhd = &ftrace_func_hash[i];
2113 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
2115 /* break up if statements for readability */
2116 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
2119 if ((flags & PROBE_TEST_DATA) && entry->data != data)
2122 /* do this last, since it is the most expensive */
2124 kallsyms_lookup(entry->ip, NULL, NULL,
2126 if (!ftrace_match(str, glob, len, type))
2130 hlist_del(&entry->node);
2131 call_rcu(&entry->rcu, ftrace_free_entry_rcu);
2134 __disable_ftrace_function_probe();
2135 mutex_unlock(&ftrace_lock);
2139 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2142 __unregister_ftrace_function_probe(glob, ops, data,
2143 PROBE_TEST_FUNC | PROBE_TEST_DATA);
2147 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
2149 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
2152 void unregister_ftrace_function_probe_all(char *glob)
2154 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
2157 static LIST_HEAD(ftrace_commands);
2158 static DEFINE_MUTEX(ftrace_cmd_mutex);
2160 int register_ftrace_command(struct ftrace_func_command *cmd)
2162 struct ftrace_func_command *p;
2165 mutex_lock(&ftrace_cmd_mutex);
2166 list_for_each_entry(p, &ftrace_commands, list) {
2167 if (strcmp(cmd->name, p->name) == 0) {
2172 list_add(&cmd->list, &ftrace_commands);
2174 mutex_unlock(&ftrace_cmd_mutex);
2179 int unregister_ftrace_command(struct ftrace_func_command *cmd)
2181 struct ftrace_func_command *p, *n;
2184 mutex_lock(&ftrace_cmd_mutex);
2185 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
2186 if (strcmp(cmd->name, p->name) == 0) {
2188 list_del_init(&p->list);
2193 mutex_unlock(&ftrace_cmd_mutex);
2198 static int ftrace_process_regex(char *buff, int len, int enable)
2200 char *func, *command, *next = buff;
2201 struct ftrace_func_command *p;
2204 func = strsep(&next, ":");
2207 if (ftrace_match_records(func, len, enable))
2214 command = strsep(&next, ":");
2216 mutex_lock(&ftrace_cmd_mutex);
2217 list_for_each_entry(p, &ftrace_commands, list) {
2218 if (strcmp(p->name, command) == 0) {
2219 ret = p->func(func, command, next, enable);
2224 mutex_unlock(&ftrace_cmd_mutex);
2230 ftrace_regex_write(struct file *file, const char __user *ubuf,
2231 size_t cnt, loff_t *ppos, int enable)
2233 struct ftrace_iterator *iter;
2234 struct trace_parser *parser;
2240 mutex_lock(&ftrace_regex_lock);
2242 if (file->f_mode & FMODE_READ) {
2243 struct seq_file *m = file->private_data;
2246 iter = file->private_data;
2248 parser = &iter->parser;
2249 read = trace_get_user(parser, ubuf, cnt, ppos);
2251 if (read >= 0 && trace_parser_loaded(parser) &&
2252 !trace_parser_cont(parser)) {
2253 ret = ftrace_process_regex(parser->buffer,
2254 parser->idx, enable);
2255 trace_parser_clear(parser);
2262 mutex_unlock(&ftrace_regex_lock);
2268 ftrace_filter_write(struct file *file, const char __user *ubuf,
2269 size_t cnt, loff_t *ppos)
2271 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
2275 ftrace_notrace_write(struct file *file, const char __user *ubuf,
2276 size_t cnt, loff_t *ppos)
2278 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
2282 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
2284 if (unlikely(ftrace_disabled))
2287 mutex_lock(&ftrace_regex_lock);
2289 ftrace_filter_reset(enable);
2291 ftrace_match_records(buf, len, enable);
2292 mutex_unlock(&ftrace_regex_lock);
2296 * ftrace_set_filter - set a function to filter on in ftrace
2297 * @buf - the string that holds the function filter text.
2298 * @len - the length of the string.
2299 * @reset - non zero to reset all filters before applying this filter.
2301 * Filters denote which functions should be enabled when tracing is enabled.
2302 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2304 void ftrace_set_filter(unsigned char *buf, int len, int reset)
2306 ftrace_set_regex(buf, len, reset, 1);
2310 * ftrace_set_notrace - set a function to not trace in ftrace
2311 * @buf - the string that holds the function notrace text.
2312 * @len - the length of the string.
2313 * @reset - non zero to reset all filters before applying this filter.
2315 * Notrace Filters denote which functions should not be enabled when tracing
2316 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2319 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
2321 ftrace_set_regex(buf, len, reset, 0);
2325 * command line interface to allow users to set filters on boot up.
2327 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
2328 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
2329 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
2331 static int __init set_ftrace_notrace(char *str)
2333 strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
2336 __setup("ftrace_notrace=", set_ftrace_notrace);
2338 static int __init set_ftrace_filter(char *str)
2340 strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
2343 __setup("ftrace_filter=", set_ftrace_filter);
2345 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2346 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
2347 static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
2349 static int __init set_graph_function(char *str)
2351 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
2354 __setup("ftrace_graph_filter=", set_graph_function);
2356 static void __init set_ftrace_early_graph(char *buf)
2362 func = strsep(&buf, ",");
2363 /* we allow only one expression at a time */
2364 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
2367 printk(KERN_DEBUG "ftrace: function %s not "
2368 "traceable\n", func);
2371 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2373 static void __init set_ftrace_early_filter(char *buf, int enable)
2378 func = strsep(&buf, ",");
2379 ftrace_set_regex(func, strlen(func), 0, enable);
2383 static void __init set_ftrace_early_filters(void)
2385 if (ftrace_filter_buf[0])
2386 set_ftrace_early_filter(ftrace_filter_buf, 1);
2387 if (ftrace_notrace_buf[0])
2388 set_ftrace_early_filter(ftrace_notrace_buf, 0);
2389 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2390 if (ftrace_graph_buf[0])
2391 set_ftrace_early_graph(ftrace_graph_buf);
2392 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2396 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
2398 struct seq_file *m = (struct seq_file *)file->private_data;
2399 struct ftrace_iterator *iter;
2400 struct trace_parser *parser;
2402 mutex_lock(&ftrace_regex_lock);
2403 if (file->f_mode & FMODE_READ) {
2406 seq_release(inode, file);
2408 iter = file->private_data;
2410 parser = &iter->parser;
2411 if (trace_parser_loaded(parser)) {
2412 parser->buffer[parser->idx] = 0;
2413 ftrace_match_records(parser->buffer, parser->idx, enable);
2416 mutex_lock(&ftrace_lock);
2417 if (ftrace_start_up && ftrace_enabled)
2418 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
2419 mutex_unlock(&ftrace_lock);
2421 trace_parser_put(parser);
2424 mutex_unlock(&ftrace_regex_lock);
2429 ftrace_filter_release(struct inode *inode, struct file *file)
2431 return ftrace_regex_release(inode, file, 1);
2435 ftrace_notrace_release(struct inode *inode, struct file *file)
2437 return ftrace_regex_release(inode, file, 0);
2440 static const struct file_operations ftrace_avail_fops = {
2441 .open = ftrace_avail_open,
2443 .llseek = seq_lseek,
2444 .release = seq_release_private,
2447 static const struct file_operations ftrace_failures_fops = {
2448 .open = ftrace_failures_open,
2450 .llseek = seq_lseek,
2451 .release = seq_release_private,
2454 static const struct file_operations ftrace_filter_fops = {
2455 .open = ftrace_filter_open,
2457 .write = ftrace_filter_write,
2458 .llseek = ftrace_regex_lseek,
2459 .release = ftrace_filter_release,
2462 static const struct file_operations ftrace_notrace_fops = {
2463 .open = ftrace_notrace_open,
2465 .write = ftrace_notrace_write,
2466 .llseek = ftrace_regex_lseek,
2467 .release = ftrace_notrace_release,
2470 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2472 static DEFINE_MUTEX(graph_lock);
2474 int ftrace_graph_count;
2475 int ftrace_graph_filter_enabled;
2476 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
2479 __g_next(struct seq_file *m, loff_t *pos)
2481 if (*pos >= ftrace_graph_count)
2483 return &ftrace_graph_funcs[*pos];
2487 g_next(struct seq_file *m, void *v, loff_t *pos)
2490 return __g_next(m, pos);
2493 static void *g_start(struct seq_file *m, loff_t *pos)
2495 mutex_lock(&graph_lock);
2497 /* Nothing, tell g_show to print all functions are enabled */
2498 if (!ftrace_graph_filter_enabled && !*pos)
2501 return __g_next(m, pos);
2504 static void g_stop(struct seq_file *m, void *p)
2506 mutex_unlock(&graph_lock);
2509 static int g_show(struct seq_file *m, void *v)
2511 unsigned long *ptr = v;
2516 if (ptr == (unsigned long *)1) {
2517 seq_printf(m, "#### all functions enabled ####\n");
2521 seq_printf(m, "%ps\n", (void *)*ptr);
2526 static const struct seq_operations ftrace_graph_seq_ops = {
2534 ftrace_graph_open(struct inode *inode, struct file *file)
2538 if (unlikely(ftrace_disabled))
2541 mutex_lock(&graph_lock);
2542 if ((file->f_mode & FMODE_WRITE) &&
2543 (file->f_flags & O_TRUNC)) {
2544 ftrace_graph_filter_enabled = 0;
2545 ftrace_graph_count = 0;
2546 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
2548 mutex_unlock(&graph_lock);
2550 if (file->f_mode & FMODE_READ)
2551 ret = seq_open(file, &ftrace_graph_seq_ops);
2557 ftrace_graph_release(struct inode *inode, struct file *file)
2559 if (file->f_mode & FMODE_READ)
2560 seq_release(inode, file);
2565 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
2567 struct dyn_ftrace *rec;
2568 struct ftrace_page *pg;
2576 if (ftrace_disabled)
2580 type = filter_parse_regex(buffer, strlen(buffer), &search, ¬);
2581 if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
2584 search_len = strlen(search);
2586 mutex_lock(&ftrace_lock);
2587 do_for_each_ftrace_rec(pg, rec) {
2589 if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
2592 if (ftrace_match_record(rec, search, search_len, type)) {
2593 /* if it is in the array */
2595 for (i = 0; i < *idx; i++) {
2596 if (array[i] == rec->ip) {
2605 array[(*idx)++] = rec->ip;
2606 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
2611 array[i] = array[--(*idx)];
2617 } while_for_each_ftrace_rec();
2619 mutex_unlock(&ftrace_lock);
2624 ftrace_graph_filter_enabled = 1;
2629 ftrace_graph_write(struct file *file, const char __user *ubuf,
2630 size_t cnt, loff_t *ppos)
2632 struct trace_parser parser;
2638 mutex_lock(&graph_lock);
2640 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
2645 read = trace_get_user(&parser, ubuf, cnt, ppos);
2647 if (read >= 0 && trace_parser_loaded((&parser))) {
2648 parser.buffer[parser.idx] = 0;
2650 /* we allow only one expression at a time */
2651 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
2660 trace_parser_put(&parser);
2662 mutex_unlock(&graph_lock);
2667 static const struct file_operations ftrace_graph_fops = {
2668 .open = ftrace_graph_open,
2670 .write = ftrace_graph_write,
2671 .release = ftrace_graph_release,
2672 .llseek = seq_lseek,
2674 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2676 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
2679 trace_create_file("available_filter_functions", 0444,
2680 d_tracer, NULL, &ftrace_avail_fops);
2682 trace_create_file("failures", 0444,
2683 d_tracer, NULL, &ftrace_failures_fops);
2685 trace_create_file("set_ftrace_filter", 0644, d_tracer,
2686 NULL, &ftrace_filter_fops);
2688 trace_create_file("set_ftrace_notrace", 0644, d_tracer,
2689 NULL, &ftrace_notrace_fops);
2691 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2692 trace_create_file("set_graph_function", 0444, d_tracer,
2694 &ftrace_graph_fops);
2695 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2700 static int ftrace_process_locs(struct module *mod,
2701 unsigned long *start,
2706 unsigned long flags;
2708 mutex_lock(&ftrace_lock);
2711 addr = ftrace_call_adjust(*p++);
2713 * Some architecture linkers will pad between
2714 * the different mcount_loc sections of different
2715 * object files to satisfy alignments.
2716 * Skip any NULL pointers.
2720 ftrace_record_ip(addr);
2723 /* disable interrupts to prevent kstop machine */
2724 local_irq_save(flags);
2725 ftrace_update_code(mod);
2726 local_irq_restore(flags);
2727 mutex_unlock(&ftrace_lock);
2732 #ifdef CONFIG_MODULES
2733 void ftrace_release_mod(struct module *mod)
2735 struct dyn_ftrace *rec;
2736 struct ftrace_page *pg;
2738 if (ftrace_disabled)
2741 mutex_lock(&ftrace_lock);
2742 do_for_each_ftrace_rec(pg, rec) {
2743 if (within_module_core(rec->ip, mod)) {
2745 * rec->ip is changed in ftrace_free_rec()
2746 * It should not between s and e if record was freed.
2748 FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE);
2749 ftrace_free_rec(rec);
2751 } while_for_each_ftrace_rec();
2752 mutex_unlock(&ftrace_lock);
2755 static void ftrace_init_module(struct module *mod,
2756 unsigned long *start, unsigned long *end)
2758 if (ftrace_disabled || start == end)
2760 ftrace_process_locs(mod, start, end);
2763 static int ftrace_module_notify(struct notifier_block *self,
2764 unsigned long val, void *data)
2766 struct module *mod = data;
2769 case MODULE_STATE_COMING:
2770 ftrace_init_module(mod, mod->ftrace_callsites,
2771 mod->ftrace_callsites +
2772 mod->num_ftrace_callsites);
2774 case MODULE_STATE_GOING:
2775 ftrace_release_mod(mod);
2782 static int ftrace_module_notify(struct notifier_block *self,
2783 unsigned long val, void *data)
2787 #endif /* CONFIG_MODULES */
2789 struct notifier_block ftrace_module_nb = {
2790 .notifier_call = ftrace_module_notify,
2794 extern unsigned long __start_mcount_loc[];
2795 extern unsigned long __stop_mcount_loc[];
2797 void __init ftrace_init(void)
2799 unsigned long count, addr, flags;
2802 /* Keep the ftrace pointer to the stub */
2803 addr = (unsigned long)ftrace_stub;
2805 local_irq_save(flags);
2806 ftrace_dyn_arch_init(&addr);
2807 local_irq_restore(flags);
2809 /* ftrace_dyn_arch_init places the return code in addr */
2813 count = __stop_mcount_loc - __start_mcount_loc;
2815 ret = ftrace_dyn_table_alloc(count);
2819 last_ftrace_enabled = ftrace_enabled = 1;
2821 ret = ftrace_process_locs(NULL,
2825 ret = register_module_notifier(&ftrace_module_nb);
2827 pr_warning("Failed to register trace ftrace module notifier\n");
2829 set_ftrace_early_filters();
2833 ftrace_disabled = 1;
2838 static int __init ftrace_nodyn_init(void)
2843 device_initcall(ftrace_nodyn_init);
2845 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
2846 static inline void ftrace_startup_enable(int command) { }
2847 /* Keep as macros so we do not need to define the commands */
2848 # define ftrace_startup(command) do { } while (0)
2849 # define ftrace_shutdown(command) do { } while (0)
2850 # define ftrace_startup_sysctl() do { } while (0)
2851 # define ftrace_shutdown_sysctl() do { } while (0)
2852 #endif /* CONFIG_DYNAMIC_FTRACE */
2854 static void clear_ftrace_swapper(void)
2856 struct task_struct *p;
2860 for_each_online_cpu(cpu) {
2862 clear_tsk_trace_trace(p);
2867 static void set_ftrace_swapper(void)
2869 struct task_struct *p;
2873 for_each_online_cpu(cpu) {
2875 set_tsk_trace_trace(p);
2880 static void clear_ftrace_pid(struct pid *pid)
2882 struct task_struct *p;
2885 do_each_pid_task(pid, PIDTYPE_PID, p) {
2886 clear_tsk_trace_trace(p);
2887 } while_each_pid_task(pid, PIDTYPE_PID, p);
2893 static void set_ftrace_pid(struct pid *pid)
2895 struct task_struct *p;
2898 do_each_pid_task(pid, PIDTYPE_PID, p) {
2899 set_tsk_trace_trace(p);
2900 } while_each_pid_task(pid, PIDTYPE_PID, p);
2904 static void clear_ftrace_pid_task(struct pid *pid)
2906 if (pid == ftrace_swapper_pid)
2907 clear_ftrace_swapper();
2909 clear_ftrace_pid(pid);
2912 static void set_ftrace_pid_task(struct pid *pid)
2914 if (pid == ftrace_swapper_pid)
2915 set_ftrace_swapper();
2917 set_ftrace_pid(pid);
2920 static int ftrace_pid_add(int p)
2923 struct ftrace_pid *fpid;
2926 mutex_lock(&ftrace_lock);
2929 pid = ftrace_swapper_pid;
2931 pid = find_get_pid(p);
2938 list_for_each_entry(fpid, &ftrace_pids, list)
2939 if (fpid->pid == pid)
2944 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
2948 list_add(&fpid->list, &ftrace_pids);
2951 set_ftrace_pid_task(pid);
2953 ftrace_update_pid_func();
2954 ftrace_startup_enable(0);
2956 mutex_unlock(&ftrace_lock);
2960 if (pid != ftrace_swapper_pid)
2964 mutex_unlock(&ftrace_lock);
2968 static void ftrace_pid_reset(void)
2970 struct ftrace_pid *fpid, *safe;
2972 mutex_lock(&ftrace_lock);
2973 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
2974 struct pid *pid = fpid->pid;
2976 clear_ftrace_pid_task(pid);
2978 list_del(&fpid->list);
2982 ftrace_update_pid_func();
2983 ftrace_startup_enable(0);
2985 mutex_unlock(&ftrace_lock);
2988 static void *fpid_start(struct seq_file *m, loff_t *pos)
2990 mutex_lock(&ftrace_lock);
2992 if (list_empty(&ftrace_pids) && (!*pos))
2995 return seq_list_start(&ftrace_pids, *pos);
2998 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
3003 return seq_list_next(v, &ftrace_pids, pos);
3006 static void fpid_stop(struct seq_file *m, void *p)
3008 mutex_unlock(&ftrace_lock);
3011 static int fpid_show(struct seq_file *m, void *v)
3013 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
3015 if (v == (void *)1) {
3016 seq_printf(m, "no pid\n");
3020 if (fpid->pid == ftrace_swapper_pid)
3021 seq_printf(m, "swapper tasks\n");
3023 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
3028 static const struct seq_operations ftrace_pid_sops = {
3029 .start = fpid_start,
3036 ftrace_pid_open(struct inode *inode, struct file *file)
3040 if ((file->f_mode & FMODE_WRITE) &&
3041 (file->f_flags & O_TRUNC))
3044 if (file->f_mode & FMODE_READ)
3045 ret = seq_open(file, &ftrace_pid_sops);
3051 ftrace_pid_write(struct file *filp, const char __user *ubuf,
3052 size_t cnt, loff_t *ppos)
3058 if (cnt >= sizeof(buf))
3061 if (copy_from_user(&buf, ubuf, cnt))
3067 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
3068 * to clean the filter quietly.
3070 tmp = strstrip(buf);
3071 if (strlen(tmp) == 0)
3074 ret = strict_strtol(tmp, 10, &val);
3078 ret = ftrace_pid_add(val);
3080 return ret ? ret : cnt;
3084 ftrace_pid_release(struct inode *inode, struct file *file)
3086 if (file->f_mode & FMODE_READ)
3087 seq_release(inode, file);
3092 static const struct file_operations ftrace_pid_fops = {
3093 .open = ftrace_pid_open,
3094 .write = ftrace_pid_write,
3096 .llseek = seq_lseek,
3097 .release = ftrace_pid_release,
3100 static __init int ftrace_init_debugfs(void)
3102 struct dentry *d_tracer;
3104 d_tracer = tracing_init_dentry();
3108 ftrace_init_dyn_debugfs(d_tracer);
3110 trace_create_file("set_ftrace_pid", 0644, d_tracer,
3111 NULL, &ftrace_pid_fops);
3113 ftrace_profile_debugfs(d_tracer);
3117 fs_initcall(ftrace_init_debugfs);
3120 * ftrace_kill - kill ftrace
3122 * This function should be used by panic code. It stops ftrace
3123 * but in a not so nice way. If you need to simply kill ftrace
3124 * from a non-atomic section, use ftrace_kill.
3126 void ftrace_kill(void)
3128 ftrace_disabled = 1;
3130 clear_ftrace_function();
3134 * register_ftrace_function - register a function for profiling
3135 * @ops - ops structure that holds the function for profiling.
3137 * Register a function to be called by all functions in the
3140 * Note: @ops->func and all the functions it calls must be labeled
3141 * with "notrace", otherwise it will go into a
3144 int register_ftrace_function(struct ftrace_ops *ops)
3148 if (unlikely(ftrace_disabled))
3151 mutex_lock(&ftrace_lock);
3153 ret = __register_ftrace_function(ops);
3156 mutex_unlock(&ftrace_lock);
3161 * unregister_ftrace_function - unregister a function for profiling.
3162 * @ops - ops structure that holds the function to unregister
3164 * Unregister a function that was added to be called by ftrace profiling.
3166 int unregister_ftrace_function(struct ftrace_ops *ops)
3170 mutex_lock(&ftrace_lock);
3171 ret = __unregister_ftrace_function(ops);
3173 mutex_unlock(&ftrace_lock);
3179 ftrace_enable_sysctl(struct ctl_table *table, int write,
3180 void __user *buffer, size_t *lenp,
3185 if (unlikely(ftrace_disabled))
3188 mutex_lock(&ftrace_lock);
3190 ret = proc_dointvec(table, write, buffer, lenp, ppos);
3192 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
3195 last_ftrace_enabled = !!ftrace_enabled;
3197 if (ftrace_enabled) {
3199 ftrace_startup_sysctl();
3201 /* we are starting ftrace again */
3202 if (ftrace_list != &ftrace_list_end) {
3203 if (ftrace_list->next == &ftrace_list_end)
3204 ftrace_trace_function = ftrace_list->func;
3206 ftrace_trace_function = ftrace_list_func;
3210 /* stopping ftrace calls (just send to ftrace_stub) */
3211 ftrace_trace_function = ftrace_stub;
3213 ftrace_shutdown_sysctl();
3217 mutex_unlock(&ftrace_lock);
3221 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3223 static int ftrace_graph_active;
3224 static struct notifier_block ftrace_suspend_notifier;
3226 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
3231 /* The callbacks that hook a function */
3232 trace_func_graph_ret_t ftrace_graph_return =
3233 (trace_func_graph_ret_t)ftrace_stub;
3234 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
3236 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
3237 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
3241 unsigned long flags;
3242 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
3243 struct task_struct *g, *t;
3245 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
3246 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
3247 * sizeof(struct ftrace_ret_stack),
3249 if (!ret_stack_list[i]) {
3257 read_lock_irqsave(&tasklist_lock, flags);
3258 do_each_thread(g, t) {
3264 if (t->ret_stack == NULL) {
3265 atomic_set(&t->tracing_graph_pause, 0);
3266 atomic_set(&t->trace_overrun, 0);
3267 t->curr_ret_stack = -1;
3268 /* Make sure the tasks see the -1 first: */
3270 t->ret_stack = ret_stack_list[start++];
3272 } while_each_thread(g, t);
3275 read_unlock_irqrestore(&tasklist_lock, flags);
3277 for (i = start; i < end; i++)
3278 kfree(ret_stack_list[i]);
3283 ftrace_graph_probe_sched_switch(void *ignore,
3284 struct task_struct *prev, struct task_struct *next)
3286 unsigned long long timestamp;
3290 * Does the user want to count the time a function was asleep.
3291 * If so, do not update the time stamps.
3293 if (trace_flags & TRACE_ITER_SLEEP_TIME)
3296 timestamp = trace_clock_local();
3298 prev->ftrace_timestamp = timestamp;
3300 /* only process tasks that we timestamped */
3301 if (!next->ftrace_timestamp)
3305 * Update all the counters in next to make up for the
3306 * time next was sleeping.
3308 timestamp -= next->ftrace_timestamp;
3310 for (index = next->curr_ret_stack; index >= 0; index--)
3311 next->ret_stack[index].calltime += timestamp;
3314 /* Allocate a return stack for each task */
3315 static int start_graph_tracing(void)
3317 struct ftrace_ret_stack **ret_stack_list;
3320 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
3321 sizeof(struct ftrace_ret_stack *),
3324 if (!ret_stack_list)
3327 /* The cpu_boot init_task->ret_stack will never be freed */
3328 for_each_online_cpu(cpu) {
3329 if (!idle_task(cpu)->ret_stack)
3330 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
3334 ret = alloc_retstack_tasklist(ret_stack_list);
3335 } while (ret == -EAGAIN);
3338 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
3340 pr_info("ftrace_graph: Couldn't activate tracepoint"
3341 " probe to kernel_sched_switch\n");
3344 kfree(ret_stack_list);
3349 * Hibernation protection.
3350 * The state of the current task is too much unstable during
3351 * suspend/restore to disk. We want to protect against that.
3354 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
3358 case PM_HIBERNATION_PREPARE:
3359 pause_graph_tracing();
3362 case PM_POST_HIBERNATION:
3363 unpause_graph_tracing();
3369 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
3370 trace_func_graph_ent_t entryfunc)
3374 mutex_lock(&ftrace_lock);
3376 /* we currently allow only one tracer registered at a time */
3377 if (ftrace_graph_active) {
3382 ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
3383 register_pm_notifier(&ftrace_suspend_notifier);
3385 ftrace_graph_active++;
3386 ret = start_graph_tracing();
3388 ftrace_graph_active--;
3392 ftrace_graph_return = retfunc;
3393 ftrace_graph_entry = entryfunc;
3395 ftrace_startup(FTRACE_START_FUNC_RET);
3398 mutex_unlock(&ftrace_lock);
3402 void unregister_ftrace_graph(void)
3404 mutex_lock(&ftrace_lock);
3406 if (unlikely(!ftrace_graph_active))
3409 ftrace_graph_active--;
3410 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
3411 ftrace_graph_entry = ftrace_graph_entry_stub;
3412 ftrace_shutdown(FTRACE_STOP_FUNC_RET);
3413 unregister_pm_notifier(&ftrace_suspend_notifier);
3414 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
3417 mutex_unlock(&ftrace_lock);
3420 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
3423 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
3425 atomic_set(&t->tracing_graph_pause, 0);
3426 atomic_set(&t->trace_overrun, 0);
3427 t->ftrace_timestamp = 0;
3428 /* make curr_ret_stack visable before we add the ret_stack */
3430 t->ret_stack = ret_stack;
3434 * Allocate a return stack for the idle task. May be the first
3435 * time through, or it may be done by CPU hotplug online.
3437 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
3439 t->curr_ret_stack = -1;
3441 * The idle task has no parent, it either has its own
3442 * stack or no stack at all.
3445 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
3447 if (ftrace_graph_active) {
3448 struct ftrace_ret_stack *ret_stack;
3450 ret_stack = per_cpu(idle_ret_stack, cpu);
3452 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
3453 * sizeof(struct ftrace_ret_stack),
3457 per_cpu(idle_ret_stack, cpu) = ret_stack;
3459 graph_init_task(t, ret_stack);
3463 /* Allocate a return stack for newly created task */
3464 void ftrace_graph_init_task(struct task_struct *t)
3466 /* Make sure we do not use the parent ret_stack */
3467 t->ret_stack = NULL;
3468 t->curr_ret_stack = -1;
3470 if (ftrace_graph_active) {
3471 struct ftrace_ret_stack *ret_stack;
3473 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
3474 * sizeof(struct ftrace_ret_stack),
3478 graph_init_task(t, ret_stack);
3482 void ftrace_graph_exit_task(struct task_struct *t)
3484 struct ftrace_ret_stack *ret_stack = t->ret_stack;
3486 t->ret_stack = NULL;
3487 /* NULL must become visible to IRQs before we free it: */
3493 void ftrace_graph_stop(void)