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 Nadia Yvette Chambers
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/bsearch.h>
26 #include <linux/module.h>
27 #include <linux/ftrace.h>
28 #include <linux/sysctl.h>
29 #include <linux/slab.h>
30 #include <linux/ctype.h>
31 #include <linux/sort.h>
32 #include <linux/list.h>
33 #include <linux/hash.h>
34 #include <linux/rcupdate.h>
36 #include <trace/events/sched.h>
38 #include <asm/setup.h>
40 #include "trace_output.h"
41 #include "trace_stat.h"
43 #define FTRACE_WARN_ON(cond) \
51 #define FTRACE_WARN_ON_ONCE(cond) \
54 if (WARN_ON_ONCE(___r)) \
59 /* hash bits for specific function selection */
60 #define FTRACE_HASH_BITS 7
61 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
62 #define FTRACE_HASH_DEFAULT_BITS 10
63 #define FTRACE_HASH_MAX_BITS 12
65 #define FL_GLOBAL_CONTROL_MASK (FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_CONTROL)
67 #ifdef CONFIG_DYNAMIC_FTRACE
68 #define INIT_REGEX_LOCK(opsname) \
69 .regex_lock = __MUTEX_INITIALIZER(opsname.regex_lock),
71 #define INIT_REGEX_LOCK(opsname)
74 static struct ftrace_ops ftrace_list_end __read_mostly = {
76 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
79 /* ftrace_enabled is a method to turn ftrace on or off */
80 int ftrace_enabled __read_mostly;
81 static int last_ftrace_enabled;
83 /* Quick disabling of function tracer. */
84 int function_trace_stop __read_mostly;
86 /* Current function tracing op */
87 struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
89 /* List for set_ftrace_pid's pids. */
90 LIST_HEAD(ftrace_pids);
92 struct list_head list;
97 * ftrace_disabled is set when an anomaly is discovered.
98 * ftrace_disabled is much stronger than ftrace_enabled.
100 static int ftrace_disabled __read_mostly;
102 static DEFINE_MUTEX(ftrace_lock);
104 static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end;
105 static struct ftrace_ops *ftrace_control_list __read_mostly = &ftrace_list_end;
106 static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
107 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
108 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
109 static struct ftrace_ops global_ops;
110 static struct ftrace_ops control_ops;
112 #if ARCH_SUPPORTS_FTRACE_OPS
113 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
114 struct ftrace_ops *op, struct pt_regs *regs);
116 /* See comment below, where ftrace_ops_list_func is defined */
117 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
118 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
122 * Traverse the ftrace_global_list, invoking all entries. The reason that we
123 * can use rcu_dereference_raw_notrace() is that elements removed from this list
124 * are simply leaked, so there is no need to interact with a grace-period
125 * mechanism. The rcu_dereference_raw_notrace() calls are needed to handle
126 * concurrent insertions into the ftrace_global_list.
128 * Silly Alpha and silly pointer-speculation compiler optimizations!
130 #define do_for_each_ftrace_op(op, list) \
131 op = rcu_dereference_raw_notrace(list); \
135 * Optimized for just a single item in the list (as that is the normal case).
137 #define while_for_each_ftrace_op(op) \
138 while (likely(op = rcu_dereference_raw_notrace((op)->next)) && \
139 unlikely((op) != &ftrace_list_end))
141 static inline void ftrace_ops_init(struct ftrace_ops *ops)
143 #ifdef CONFIG_DYNAMIC_FTRACE
144 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
145 mutex_init(&ops->regex_lock);
146 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
152 * ftrace_nr_registered_ops - return number of ops registered
154 * Returns the number of ftrace_ops registered and tracing functions
156 int ftrace_nr_registered_ops(void)
158 struct ftrace_ops *ops;
161 mutex_lock(&ftrace_lock);
163 for (ops = ftrace_ops_list;
164 ops != &ftrace_list_end; ops = ops->next)
167 mutex_unlock(&ftrace_lock);
173 ftrace_global_list_func(unsigned long ip, unsigned long parent_ip,
174 struct ftrace_ops *op, struct pt_regs *regs)
178 bit = trace_test_and_set_recursion(TRACE_GLOBAL_START, TRACE_GLOBAL_MAX);
182 do_for_each_ftrace_op(op, ftrace_global_list) {
183 op->func(ip, parent_ip, op, regs);
184 } while_for_each_ftrace_op(op);
186 trace_clear_recursion(bit);
189 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
190 struct ftrace_ops *op, struct pt_regs *regs)
192 if (!test_tsk_trace_trace(current))
195 ftrace_pid_function(ip, parent_ip, op, regs);
198 static void set_ftrace_pid_function(ftrace_func_t func)
200 /* do not set ftrace_pid_function to itself! */
201 if (func != ftrace_pid_func)
202 ftrace_pid_function = func;
206 * clear_ftrace_function - reset the ftrace function
208 * This NULLs the ftrace function and in essence stops
209 * tracing. There may be lag
211 void clear_ftrace_function(void)
213 ftrace_trace_function = ftrace_stub;
214 ftrace_pid_function = ftrace_stub;
217 static void control_ops_disable_all(struct ftrace_ops *ops)
221 for_each_possible_cpu(cpu)
222 *per_cpu_ptr(ops->disabled, cpu) = 1;
225 static int control_ops_alloc(struct ftrace_ops *ops)
227 int __percpu *disabled;
229 disabled = alloc_percpu(int);
233 ops->disabled = disabled;
234 control_ops_disable_all(ops);
238 static void control_ops_free(struct ftrace_ops *ops)
240 free_percpu(ops->disabled);
243 static void update_global_ops(void)
248 * If there's only one function registered, then call that
249 * function directly. Otherwise, we need to iterate over the
250 * registered callers.
252 if (ftrace_global_list == &ftrace_list_end ||
253 ftrace_global_list->next == &ftrace_list_end) {
254 func = ftrace_global_list->func;
256 * As we are calling the function directly.
257 * If it does not have recursion protection,
258 * the function_trace_op needs to be updated
261 if (ftrace_global_list->flags & FTRACE_OPS_FL_RECURSION_SAFE)
262 global_ops.flags |= FTRACE_OPS_FL_RECURSION_SAFE;
264 global_ops.flags &= ~FTRACE_OPS_FL_RECURSION_SAFE;
266 func = ftrace_global_list_func;
267 /* The list has its own recursion protection. */
268 global_ops.flags |= FTRACE_OPS_FL_RECURSION_SAFE;
272 /* If we filter on pids, update to use the pid function */
273 if (!list_empty(&ftrace_pids)) {
274 set_ftrace_pid_function(func);
275 func = ftrace_pid_func;
278 global_ops.func = func;
281 static void update_ftrace_function(void)
288 * If we are at the end of the list and this ops is
289 * recursion safe and not dynamic and the arch supports passing ops,
290 * then have the mcount trampoline call the function directly.
292 if (ftrace_ops_list == &ftrace_list_end ||
293 (ftrace_ops_list->next == &ftrace_list_end &&
294 !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC) &&
295 (ftrace_ops_list->flags & FTRACE_OPS_FL_RECURSION_SAFE) &&
296 !FTRACE_FORCE_LIST_FUNC)) {
297 /* Set the ftrace_ops that the arch callback uses */
298 if (ftrace_ops_list == &global_ops)
299 function_trace_op = ftrace_global_list;
301 function_trace_op = ftrace_ops_list;
302 func = ftrace_ops_list->func;
304 /* Just use the default ftrace_ops */
305 function_trace_op = &ftrace_list_end;
306 func = ftrace_ops_list_func;
309 ftrace_trace_function = func;
312 static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
316 * We are entering ops into the list but another
317 * CPU might be walking that list. We need to make sure
318 * the ops->next pointer is valid before another CPU sees
319 * the ops pointer included into the list.
321 rcu_assign_pointer(*list, ops);
324 static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
326 struct ftrace_ops **p;
329 * If we are removing the last function, then simply point
330 * to the ftrace_stub.
332 if (*list == ops && ops->next == &ftrace_list_end) {
333 *list = &ftrace_list_end;
337 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
348 static void add_ftrace_list_ops(struct ftrace_ops **list,
349 struct ftrace_ops *main_ops,
350 struct ftrace_ops *ops)
352 int first = *list == &ftrace_list_end;
353 add_ftrace_ops(list, ops);
355 add_ftrace_ops(&ftrace_ops_list, main_ops);
358 static int remove_ftrace_list_ops(struct ftrace_ops **list,
359 struct ftrace_ops *main_ops,
360 struct ftrace_ops *ops)
362 int ret = remove_ftrace_ops(list, ops);
363 if (!ret && *list == &ftrace_list_end)
364 ret = remove_ftrace_ops(&ftrace_ops_list, main_ops);
368 static int __register_ftrace_function(struct ftrace_ops *ops)
370 if (unlikely(ftrace_disabled))
373 if (FTRACE_WARN_ON(ops == &global_ops))
376 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
379 /* We don't support both control and global flags set. */
380 if ((ops->flags & FL_GLOBAL_CONTROL_MASK) == FL_GLOBAL_CONTROL_MASK)
383 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
385 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
386 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
387 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
389 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
390 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
393 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
394 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
397 if (!core_kernel_data((unsigned long)ops))
398 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
400 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
401 add_ftrace_list_ops(&ftrace_global_list, &global_ops, ops);
402 ops->flags |= FTRACE_OPS_FL_ENABLED;
403 } else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
404 if (control_ops_alloc(ops))
406 add_ftrace_list_ops(&ftrace_control_list, &control_ops, ops);
408 add_ftrace_ops(&ftrace_ops_list, ops);
411 update_ftrace_function();
416 static void ftrace_sync(struct work_struct *work)
419 * This function is just a stub to implement a hard force
420 * of synchronize_sched(). This requires synchronizing
421 * tasks even in userspace and idle.
423 * Yes, function tracing is rude.
427 static int __unregister_ftrace_function(struct ftrace_ops *ops)
434 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
437 if (FTRACE_WARN_ON(ops == &global_ops))
440 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
441 ret = remove_ftrace_list_ops(&ftrace_global_list,
444 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
445 } else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
446 ret = remove_ftrace_list_ops(&ftrace_control_list,
450 * The ftrace_ops is now removed from the list,
451 * so there'll be no new users. We must ensure
452 * all current users are done before we free
454 * Note synchronize_sched() is not enough, as we
455 * use preempt_disable() to do RCU, but the function
456 * tracer can be called where RCU is not active
457 * (before user_exit()).
459 schedule_on_each_cpu(ftrace_sync);
460 control_ops_free(ops);
463 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
469 update_ftrace_function();
472 * Dynamic ops may be freed, we must make sure that all
473 * callers are done before leaving this function.
475 * Again, normal synchronize_sched() is not good enough.
476 * We need to do a hard force of sched synchronization.
478 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
479 schedule_on_each_cpu(ftrace_sync);
485 static void ftrace_update_pid_func(void)
487 /* Only do something if we are tracing something */
488 if (ftrace_trace_function == ftrace_stub)
491 update_ftrace_function();
494 #ifdef CONFIG_FUNCTION_PROFILER
495 struct ftrace_profile {
496 struct hlist_node node;
498 unsigned long counter;
499 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
500 unsigned long long time;
501 unsigned long long time_squared;
505 struct ftrace_profile_page {
506 struct ftrace_profile_page *next;
508 struct ftrace_profile records[];
511 struct ftrace_profile_stat {
513 struct hlist_head *hash;
514 struct ftrace_profile_page *pages;
515 struct ftrace_profile_page *start;
516 struct tracer_stat stat;
519 #define PROFILE_RECORDS_SIZE \
520 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
522 #define PROFILES_PER_PAGE \
523 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
525 static int ftrace_profile_enabled __read_mostly;
527 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
528 static DEFINE_MUTEX(ftrace_profile_lock);
530 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
532 #define FTRACE_PROFILE_HASH_BITS 10
533 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
536 function_stat_next(void *v, int idx)
538 struct ftrace_profile *rec = v;
539 struct ftrace_profile_page *pg;
541 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
547 if ((void *)rec >= (void *)&pg->records[pg->index]) {
551 rec = &pg->records[0];
559 static void *function_stat_start(struct tracer_stat *trace)
561 struct ftrace_profile_stat *stat =
562 container_of(trace, struct ftrace_profile_stat, stat);
564 if (!stat || !stat->start)
567 return function_stat_next(&stat->start->records[0], 0);
570 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
571 /* function graph compares on total time */
572 static int function_stat_cmp(void *p1, void *p2)
574 struct ftrace_profile *a = p1;
575 struct ftrace_profile *b = p2;
577 if (a->time < b->time)
579 if (a->time > b->time)
585 /* not function graph compares against hits */
586 static int function_stat_cmp(void *p1, void *p2)
588 struct ftrace_profile *a = p1;
589 struct ftrace_profile *b = p2;
591 if (a->counter < b->counter)
593 if (a->counter > b->counter)
600 static int function_stat_headers(struct seq_file *m)
602 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
603 seq_printf(m, " Function "
606 "--- ---- --- ---\n");
608 seq_printf(m, " Function Hit\n"
614 static int function_stat_show(struct seq_file *m, void *v)
616 struct ftrace_profile *rec = v;
617 char str[KSYM_SYMBOL_LEN];
619 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
620 static struct trace_seq s;
621 unsigned long long avg;
622 unsigned long long stddev;
624 mutex_lock(&ftrace_profile_lock);
626 /* we raced with function_profile_reset() */
627 if (unlikely(rec->counter == 0)) {
632 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
633 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
635 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
638 do_div(avg, rec->counter);
640 /* Sample standard deviation (s^2) */
641 if (rec->counter <= 1)
645 * Apply Welford's method:
646 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
648 stddev = rec->counter * rec->time_squared -
649 rec->time * rec->time;
652 * Divide only 1000 for ns^2 -> us^2 conversion.
653 * trace_print_graph_duration will divide 1000 again.
655 do_div(stddev, rec->counter * (rec->counter - 1) * 1000);
659 trace_print_graph_duration(rec->time, &s);
660 trace_seq_puts(&s, " ");
661 trace_print_graph_duration(avg, &s);
662 trace_seq_puts(&s, " ");
663 trace_print_graph_duration(stddev, &s);
664 trace_print_seq(m, &s);
668 mutex_unlock(&ftrace_profile_lock);
673 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
675 struct ftrace_profile_page *pg;
677 pg = stat->pages = stat->start;
680 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
685 memset(stat->hash, 0,
686 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
689 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
691 struct ftrace_profile_page *pg;
696 /* If we already allocated, do nothing */
700 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
704 #ifdef CONFIG_DYNAMIC_FTRACE
705 functions = ftrace_update_tot_cnt;
708 * We do not know the number of functions that exist because
709 * dynamic tracing is what counts them. With past experience
710 * we have around 20K functions. That should be more than enough.
711 * It is highly unlikely we will execute every function in
717 pg = stat->start = stat->pages;
719 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
721 for (i = 1; i < pages; i++) {
722 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
733 unsigned long tmp = (unsigned long)pg;
745 static int ftrace_profile_init_cpu(int cpu)
747 struct ftrace_profile_stat *stat;
750 stat = &per_cpu(ftrace_profile_stats, cpu);
753 /* If the profile is already created, simply reset it */
754 ftrace_profile_reset(stat);
759 * We are profiling all functions, but usually only a few thousand
760 * functions are hit. We'll make a hash of 1024 items.
762 size = FTRACE_PROFILE_HASH_SIZE;
764 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
769 /* Preallocate the function profiling pages */
770 if (ftrace_profile_pages_init(stat) < 0) {
779 static int ftrace_profile_init(void)
784 for_each_online_cpu(cpu) {
785 ret = ftrace_profile_init_cpu(cpu);
793 /* interrupts must be disabled */
794 static struct ftrace_profile *
795 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
797 struct ftrace_profile *rec;
798 struct hlist_head *hhd;
801 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
802 hhd = &stat->hash[key];
804 if (hlist_empty(hhd))
807 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
815 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
816 struct ftrace_profile *rec)
820 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
821 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
825 * The memory is already allocated, this simply finds a new record to use.
827 static struct ftrace_profile *
828 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
830 struct ftrace_profile *rec = NULL;
832 /* prevent recursion (from NMIs) */
833 if (atomic_inc_return(&stat->disabled) != 1)
837 * Try to find the function again since an NMI
838 * could have added it
840 rec = ftrace_find_profiled_func(stat, ip);
844 if (stat->pages->index == PROFILES_PER_PAGE) {
845 if (!stat->pages->next)
847 stat->pages = stat->pages->next;
850 rec = &stat->pages->records[stat->pages->index++];
852 ftrace_add_profile(stat, rec);
855 atomic_dec(&stat->disabled);
861 function_profile_call(unsigned long ip, unsigned long parent_ip,
862 struct ftrace_ops *ops, struct pt_regs *regs)
864 struct ftrace_profile_stat *stat;
865 struct ftrace_profile *rec;
868 if (!ftrace_profile_enabled)
871 local_irq_save(flags);
873 stat = &__get_cpu_var(ftrace_profile_stats);
874 if (!stat->hash || !ftrace_profile_enabled)
877 rec = ftrace_find_profiled_func(stat, ip);
879 rec = ftrace_profile_alloc(stat, ip);
886 local_irq_restore(flags);
889 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
890 static int profile_graph_entry(struct ftrace_graph_ent *trace)
892 function_profile_call(trace->func, 0, NULL, NULL);
896 static void profile_graph_return(struct ftrace_graph_ret *trace)
898 struct ftrace_profile_stat *stat;
899 unsigned long long calltime;
900 struct ftrace_profile *rec;
903 local_irq_save(flags);
904 stat = &__get_cpu_var(ftrace_profile_stats);
905 if (!stat->hash || !ftrace_profile_enabled)
908 /* If the calltime was zero'd ignore it */
909 if (!trace->calltime)
912 calltime = trace->rettime - trace->calltime;
914 if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
917 index = trace->depth;
919 /* Append this call time to the parent time to subtract */
921 current->ret_stack[index - 1].subtime += calltime;
923 if (current->ret_stack[index].subtime < calltime)
924 calltime -= current->ret_stack[index].subtime;
929 rec = ftrace_find_profiled_func(stat, trace->func);
931 rec->time += calltime;
932 rec->time_squared += calltime * calltime;
936 local_irq_restore(flags);
939 static int register_ftrace_profiler(void)
941 return register_ftrace_graph(&profile_graph_return,
942 &profile_graph_entry);
945 static void unregister_ftrace_profiler(void)
947 unregister_ftrace_graph();
950 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
951 .func = function_profile_call,
952 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
953 INIT_REGEX_LOCK(ftrace_profile_ops)
956 static int register_ftrace_profiler(void)
958 return register_ftrace_function(&ftrace_profile_ops);
961 static void unregister_ftrace_profiler(void)
963 unregister_ftrace_function(&ftrace_profile_ops);
965 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
968 ftrace_profile_write(struct file *filp, const char __user *ubuf,
969 size_t cnt, loff_t *ppos)
974 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
980 mutex_lock(&ftrace_profile_lock);
981 if (ftrace_profile_enabled ^ val) {
983 ret = ftrace_profile_init();
989 ret = register_ftrace_profiler();
994 ftrace_profile_enabled = 1;
996 ftrace_profile_enabled = 0;
998 * unregister_ftrace_profiler calls stop_machine
999 * so this acts like an synchronize_sched.
1001 unregister_ftrace_profiler();
1005 mutex_unlock(&ftrace_profile_lock);
1013 ftrace_profile_read(struct file *filp, char __user *ubuf,
1014 size_t cnt, loff_t *ppos)
1016 char buf[64]; /* big enough to hold a number */
1019 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
1020 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1023 static const struct file_operations ftrace_profile_fops = {
1024 .open = tracing_open_generic,
1025 .read = ftrace_profile_read,
1026 .write = ftrace_profile_write,
1027 .llseek = default_llseek,
1030 /* used to initialize the real stat files */
1031 static struct tracer_stat function_stats __initdata = {
1032 .name = "functions",
1033 .stat_start = function_stat_start,
1034 .stat_next = function_stat_next,
1035 .stat_cmp = function_stat_cmp,
1036 .stat_headers = function_stat_headers,
1037 .stat_show = function_stat_show
1040 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
1042 struct ftrace_profile_stat *stat;
1043 struct dentry *entry;
1048 for_each_possible_cpu(cpu) {
1049 stat = &per_cpu(ftrace_profile_stats, cpu);
1051 /* allocate enough for function name + cpu number */
1052 name = kmalloc(32, GFP_KERNEL);
1055 * The files created are permanent, if something happens
1056 * we still do not free memory.
1059 "Could not allocate stat file for cpu %d\n",
1063 stat->stat = function_stats;
1064 snprintf(name, 32, "function%d", cpu);
1065 stat->stat.name = name;
1066 ret = register_stat_tracer(&stat->stat);
1069 "Could not register function stat for cpu %d\n",
1076 entry = debugfs_create_file("function_profile_enabled", 0644,
1077 d_tracer, NULL, &ftrace_profile_fops);
1079 pr_warning("Could not create debugfs "
1080 "'function_profile_enabled' entry\n");
1083 #else /* CONFIG_FUNCTION_PROFILER */
1084 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
1087 #endif /* CONFIG_FUNCTION_PROFILER */
1089 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1092 ftrace_filter_lseek(struct file *file, loff_t offset, int whence)
1096 if (file->f_mode & FMODE_READ)
1097 ret = seq_lseek(file, offset, whence);
1099 file->f_pos = ret = 1;
1104 #ifdef CONFIG_DYNAMIC_FTRACE
1106 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1107 # error Dynamic ftrace depends on MCOUNT_RECORD
1110 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
1112 struct ftrace_func_probe {
1113 struct hlist_node node;
1114 struct ftrace_probe_ops *ops;
1115 unsigned long flags;
1118 struct list_head free_list;
1121 struct ftrace_func_entry {
1122 struct hlist_node hlist;
1126 struct ftrace_hash {
1127 unsigned long size_bits;
1128 struct hlist_head *buckets;
1129 unsigned long count;
1130 struct rcu_head rcu;
1134 * We make these constant because no one should touch them,
1135 * but they are used as the default "empty hash", to avoid allocating
1136 * it all the time. These are in a read only section such that if
1137 * anyone does try to modify it, it will cause an exception.
1139 static const struct hlist_head empty_buckets[1];
1140 static const struct ftrace_hash empty_hash = {
1141 .buckets = (struct hlist_head *)empty_buckets,
1143 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1145 static struct ftrace_ops global_ops = {
1146 .func = ftrace_stub,
1147 .notrace_hash = EMPTY_HASH,
1148 .filter_hash = EMPTY_HASH,
1149 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
1150 INIT_REGEX_LOCK(global_ops)
1153 struct ftrace_page {
1154 struct ftrace_page *next;
1155 struct dyn_ftrace *records;
1160 static struct ftrace_page *ftrace_new_pgs;
1162 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1163 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1165 /* estimate from running different kernels */
1166 #define NR_TO_INIT 10000
1168 static struct ftrace_page *ftrace_pages_start;
1169 static struct ftrace_page *ftrace_pages;
1171 static bool ftrace_hash_empty(struct ftrace_hash *hash)
1173 return !hash || !hash->count;
1176 static struct ftrace_func_entry *
1177 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1180 struct ftrace_func_entry *entry;
1181 struct hlist_head *hhd;
1183 if (ftrace_hash_empty(hash))
1186 if (hash->size_bits > 0)
1187 key = hash_long(ip, hash->size_bits);
1191 hhd = &hash->buckets[key];
1193 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1194 if (entry->ip == ip)
1200 static void __add_hash_entry(struct ftrace_hash *hash,
1201 struct ftrace_func_entry *entry)
1203 struct hlist_head *hhd;
1206 if (hash->size_bits)
1207 key = hash_long(entry->ip, hash->size_bits);
1211 hhd = &hash->buckets[key];
1212 hlist_add_head(&entry->hlist, hhd);
1216 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1218 struct ftrace_func_entry *entry;
1220 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1225 __add_hash_entry(hash, entry);
1231 free_hash_entry(struct ftrace_hash *hash,
1232 struct ftrace_func_entry *entry)
1234 hlist_del(&entry->hlist);
1240 remove_hash_entry(struct ftrace_hash *hash,
1241 struct ftrace_func_entry *entry)
1243 hlist_del(&entry->hlist);
1247 static void ftrace_hash_clear(struct ftrace_hash *hash)
1249 struct hlist_head *hhd;
1250 struct hlist_node *tn;
1251 struct ftrace_func_entry *entry;
1252 int size = 1 << hash->size_bits;
1258 for (i = 0; i < size; i++) {
1259 hhd = &hash->buckets[i];
1260 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1261 free_hash_entry(hash, entry);
1263 FTRACE_WARN_ON(hash->count);
1266 static void free_ftrace_hash(struct ftrace_hash *hash)
1268 if (!hash || hash == EMPTY_HASH)
1270 ftrace_hash_clear(hash);
1271 kfree(hash->buckets);
1275 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1277 struct ftrace_hash *hash;
1279 hash = container_of(rcu, struct ftrace_hash, rcu);
1280 free_ftrace_hash(hash);
1283 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1285 if (!hash || hash == EMPTY_HASH)
1287 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1290 void ftrace_free_filter(struct ftrace_ops *ops)
1292 ftrace_ops_init(ops);
1293 free_ftrace_hash(ops->filter_hash);
1294 free_ftrace_hash(ops->notrace_hash);
1297 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1299 struct ftrace_hash *hash;
1302 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1306 size = 1 << size_bits;
1307 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1309 if (!hash->buckets) {
1314 hash->size_bits = size_bits;
1319 static struct ftrace_hash *
1320 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1322 struct ftrace_func_entry *entry;
1323 struct ftrace_hash *new_hash;
1328 new_hash = alloc_ftrace_hash(size_bits);
1333 if (ftrace_hash_empty(hash))
1336 size = 1 << hash->size_bits;
1337 for (i = 0; i < size; i++) {
1338 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1339 ret = add_hash_entry(new_hash, entry->ip);
1345 FTRACE_WARN_ON(new_hash->count != hash->count);
1350 free_ftrace_hash(new_hash);
1355 ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash);
1357 ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash);
1360 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1361 struct ftrace_hash **dst, struct ftrace_hash *src)
1363 struct ftrace_func_entry *entry;
1364 struct hlist_node *tn;
1365 struct hlist_head *hhd;
1366 struct ftrace_hash *old_hash;
1367 struct ftrace_hash *new_hash;
1368 int size = src->count;
1374 * Remove the current set, update the hash and add
1377 ftrace_hash_rec_disable(ops, enable);
1380 * If the new source is empty, just free dst and assign it
1384 free_ftrace_hash_rcu(*dst);
1385 rcu_assign_pointer(*dst, EMPTY_HASH);
1386 /* still need to update the function records */
1392 * Make the hash size about 1/2 the # found
1394 for (size /= 2; size; size >>= 1)
1397 /* Don't allocate too much */
1398 if (bits > FTRACE_HASH_MAX_BITS)
1399 bits = FTRACE_HASH_MAX_BITS;
1402 new_hash = alloc_ftrace_hash(bits);
1406 size = 1 << src->size_bits;
1407 for (i = 0; i < size; i++) {
1408 hhd = &src->buckets[i];
1409 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1410 remove_hash_entry(src, entry);
1411 __add_hash_entry(new_hash, entry);
1416 rcu_assign_pointer(*dst, new_hash);
1417 free_ftrace_hash_rcu(old_hash);
1422 * Enable regardless of ret:
1423 * On success, we enable the new hash.
1424 * On failure, we re-enable the original hash.
1426 ftrace_hash_rec_enable(ops, enable);
1432 * Test the hashes for this ops to see if we want to call
1433 * the ops->func or not.
1435 * It's a match if the ip is in the ops->filter_hash or
1436 * the filter_hash does not exist or is empty,
1438 * the ip is not in the ops->notrace_hash.
1440 * This needs to be called with preemption disabled as
1441 * the hashes are freed with call_rcu_sched().
1444 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1446 struct ftrace_hash *filter_hash;
1447 struct ftrace_hash *notrace_hash;
1450 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1452 * There's a small race when adding ops that the ftrace handler
1453 * that wants regs, may be called without them. We can not
1454 * allow that handler to be called if regs is NULL.
1456 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1460 filter_hash = rcu_dereference_raw_notrace(ops->filter_hash);
1461 notrace_hash = rcu_dereference_raw_notrace(ops->notrace_hash);
1463 if ((ftrace_hash_empty(filter_hash) ||
1464 ftrace_lookup_ip(filter_hash, ip)) &&
1465 (ftrace_hash_empty(notrace_hash) ||
1466 !ftrace_lookup_ip(notrace_hash, ip)))
1475 * This is a double for. Do not use 'break' to break out of the loop,
1476 * you must use a goto.
1478 #define do_for_each_ftrace_rec(pg, rec) \
1479 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1481 for (_____i = 0; _____i < pg->index; _____i++) { \
1482 rec = &pg->records[_____i];
1484 #define while_for_each_ftrace_rec() \
1489 static int ftrace_cmp_recs(const void *a, const void *b)
1491 const struct dyn_ftrace *key = a;
1492 const struct dyn_ftrace *rec = b;
1494 if (key->flags < rec->ip)
1496 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1501 static unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1503 struct ftrace_page *pg;
1504 struct dyn_ftrace *rec;
1505 struct dyn_ftrace key;
1508 key.flags = end; /* overload flags, as it is unsigned long */
1510 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1511 if (end < pg->records[0].ip ||
1512 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1514 rec = bsearch(&key, pg->records, pg->index,
1515 sizeof(struct dyn_ftrace),
1525 * ftrace_location - return true if the ip giving is a traced location
1526 * @ip: the instruction pointer to check
1528 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1529 * That is, the instruction that is either a NOP or call to
1530 * the function tracer. It checks the ftrace internal tables to
1531 * determine if the address belongs or not.
1533 unsigned long ftrace_location(unsigned long ip)
1535 return ftrace_location_range(ip, ip);
1539 * ftrace_text_reserved - return true if range contains an ftrace location
1540 * @start: start of range to search
1541 * @end: end of range to search (inclusive). @end points to the last byte to check.
1543 * Returns 1 if @start and @end contains a ftrace location.
1544 * That is, the instruction that is either a NOP or call to
1545 * the function tracer. It checks the ftrace internal tables to
1546 * determine if the address belongs or not.
1548 int ftrace_text_reserved(void *start, void *end)
1552 ret = ftrace_location_range((unsigned long)start,
1553 (unsigned long)end);
1558 static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
1562 struct ftrace_hash *hash;
1563 struct ftrace_hash *other_hash;
1564 struct ftrace_page *pg;
1565 struct dyn_ftrace *rec;
1569 /* Only update if the ops has been registered */
1570 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1574 * In the filter_hash case:
1575 * If the count is zero, we update all records.
1576 * Otherwise we just update the items in the hash.
1578 * In the notrace_hash case:
1579 * We enable the update in the hash.
1580 * As disabling notrace means enabling the tracing,
1581 * and enabling notrace means disabling, the inc variable
1585 hash = ops->filter_hash;
1586 other_hash = ops->notrace_hash;
1587 if (ftrace_hash_empty(hash))
1591 hash = ops->notrace_hash;
1592 other_hash = ops->filter_hash;
1594 * If the notrace hash has no items,
1595 * then there's nothing to do.
1597 if (ftrace_hash_empty(hash))
1601 do_for_each_ftrace_rec(pg, rec) {
1602 int in_other_hash = 0;
1608 * Only the filter_hash affects all records.
1609 * Update if the record is not in the notrace hash.
1611 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1614 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1615 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1620 if (filter_hash && in_hash && !in_other_hash)
1622 else if (!filter_hash && in_hash &&
1623 (in_other_hash || ftrace_hash_empty(other_hash)))
1631 if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX))
1634 * If any ops wants regs saved for this function
1635 * then all ops will get saved regs.
1637 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1638 rec->flags |= FTRACE_FL_REGS;
1640 if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
1645 /* Shortcut, if we handled all records, we are done. */
1646 if (!all && count == hash->count)
1648 } while_for_each_ftrace_rec();
1651 static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
1654 __ftrace_hash_rec_update(ops, filter_hash, 0);
1657 static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
1660 __ftrace_hash_rec_update(ops, filter_hash, 1);
1663 static void print_ip_ins(const char *fmt, unsigned char *p)
1667 printk(KERN_CONT "%s", fmt);
1669 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1670 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1674 * ftrace_bug - report and shutdown function tracer
1675 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1676 * @ip: The address that failed
1678 * The arch code that enables or disables the function tracing
1679 * can call ftrace_bug() when it has detected a problem in
1680 * modifying the code. @failed should be one of either:
1681 * EFAULT - if the problem happens on reading the @ip address
1682 * EINVAL - if what is read at @ip is not what was expected
1683 * EPERM - if the problem happens on writting to the @ip address
1685 void ftrace_bug(int failed, unsigned long ip)
1689 FTRACE_WARN_ON_ONCE(1);
1690 pr_info("ftrace faulted on modifying ");
1694 FTRACE_WARN_ON_ONCE(1);
1695 pr_info("ftrace failed to modify ");
1697 print_ip_ins(" actual: ", (unsigned char *)ip);
1698 printk(KERN_CONT "\n");
1701 FTRACE_WARN_ON_ONCE(1);
1702 pr_info("ftrace faulted on writing ");
1706 FTRACE_WARN_ON_ONCE(1);
1707 pr_info("ftrace faulted on unknown error ");
1712 static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
1714 unsigned long flag = 0UL;
1717 * If we are updating calls:
1719 * If the record has a ref count, then we need to enable it
1720 * because someone is using it.
1722 * Otherwise we make sure its disabled.
1724 * If we are disabling calls, then disable all records that
1727 if (enable && (rec->flags & ~FTRACE_FL_MASK))
1728 flag = FTRACE_FL_ENABLED;
1731 * If enabling and the REGS flag does not match the REGS_EN, then
1732 * do not ignore this record. Set flags to fail the compare against
1736 (!(rec->flags & FTRACE_FL_REGS) != !(rec->flags & FTRACE_FL_REGS_EN)))
1737 flag |= FTRACE_FL_REGS;
1739 /* If the state of this record hasn't changed, then do nothing */
1740 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1741 return FTRACE_UPDATE_IGNORE;
1744 /* Save off if rec is being enabled (for return value) */
1745 flag ^= rec->flags & FTRACE_FL_ENABLED;
1748 rec->flags |= FTRACE_FL_ENABLED;
1749 if (flag & FTRACE_FL_REGS) {
1750 if (rec->flags & FTRACE_FL_REGS)
1751 rec->flags |= FTRACE_FL_REGS_EN;
1753 rec->flags &= ~FTRACE_FL_REGS_EN;
1758 * If this record is being updated from a nop, then
1759 * return UPDATE_MAKE_CALL.
1760 * Otherwise, if the EN flag is set, then return
1761 * UPDATE_MODIFY_CALL_REGS to tell the caller to convert
1762 * from the non-save regs, to a save regs function.
1764 * return UPDATE_MODIFY_CALL to tell the caller to convert
1765 * from the save regs, to a non-save regs function.
1767 if (flag & FTRACE_FL_ENABLED)
1768 return FTRACE_UPDATE_MAKE_CALL;
1769 else if (rec->flags & FTRACE_FL_REGS_EN)
1770 return FTRACE_UPDATE_MODIFY_CALL_REGS;
1772 return FTRACE_UPDATE_MODIFY_CALL;
1776 /* If there's no more users, clear all flags */
1777 if (!(rec->flags & ~FTRACE_FL_MASK))
1780 /* Just disable the record (keep REGS state) */
1781 rec->flags &= ~FTRACE_FL_ENABLED;
1784 return FTRACE_UPDATE_MAKE_NOP;
1788 * ftrace_update_record, set a record that now is tracing or not
1789 * @rec: the record to update
1790 * @enable: set to 1 if the record is tracing, zero to force disable
1792 * The records that represent all functions that can be traced need
1793 * to be updated when tracing has been enabled.
1795 int ftrace_update_record(struct dyn_ftrace *rec, int enable)
1797 return ftrace_check_record(rec, enable, 1);
1801 * ftrace_test_record, check if the record has been enabled or not
1802 * @rec: the record to test
1803 * @enable: set to 1 to check if enabled, 0 if it is disabled
1805 * The arch code may need to test if a record is already set to
1806 * tracing to determine how to modify the function code that it
1809 int ftrace_test_record(struct dyn_ftrace *rec, int enable)
1811 return ftrace_check_record(rec, enable, 0);
1815 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1817 unsigned long ftrace_old_addr;
1818 unsigned long ftrace_addr;
1821 ret = ftrace_update_record(rec, enable);
1823 if (rec->flags & FTRACE_FL_REGS)
1824 ftrace_addr = (unsigned long)FTRACE_REGS_ADDR;
1826 ftrace_addr = (unsigned long)FTRACE_ADDR;
1829 case FTRACE_UPDATE_IGNORE:
1832 case FTRACE_UPDATE_MAKE_CALL:
1833 return ftrace_make_call(rec, ftrace_addr);
1835 case FTRACE_UPDATE_MAKE_NOP:
1836 return ftrace_make_nop(NULL, rec, ftrace_addr);
1838 case FTRACE_UPDATE_MODIFY_CALL_REGS:
1839 case FTRACE_UPDATE_MODIFY_CALL:
1840 if (rec->flags & FTRACE_FL_REGS)
1841 ftrace_old_addr = (unsigned long)FTRACE_ADDR;
1843 ftrace_old_addr = (unsigned long)FTRACE_REGS_ADDR;
1845 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
1848 return -1; /* unknow ftrace bug */
1851 void __weak ftrace_replace_code(int enable)
1853 struct dyn_ftrace *rec;
1854 struct ftrace_page *pg;
1857 if (unlikely(ftrace_disabled))
1860 do_for_each_ftrace_rec(pg, rec) {
1861 failed = __ftrace_replace_code(rec, enable);
1863 ftrace_bug(failed, rec->ip);
1864 /* Stop processing */
1867 } while_for_each_ftrace_rec();
1870 struct ftrace_rec_iter {
1871 struct ftrace_page *pg;
1876 * ftrace_rec_iter_start, start up iterating over traced functions
1878 * Returns an iterator handle that is used to iterate over all
1879 * the records that represent address locations where functions
1882 * May return NULL if no records are available.
1884 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
1887 * We only use a single iterator.
1888 * Protected by the ftrace_lock mutex.
1890 static struct ftrace_rec_iter ftrace_rec_iter;
1891 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
1893 iter->pg = ftrace_pages_start;
1896 /* Could have empty pages */
1897 while (iter->pg && !iter->pg->index)
1898 iter->pg = iter->pg->next;
1907 * ftrace_rec_iter_next, get the next record to process.
1908 * @iter: The handle to the iterator.
1910 * Returns the next iterator after the given iterator @iter.
1912 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
1916 if (iter->index >= iter->pg->index) {
1917 iter->pg = iter->pg->next;
1920 /* Could have empty pages */
1921 while (iter->pg && !iter->pg->index)
1922 iter->pg = iter->pg->next;
1932 * ftrace_rec_iter_record, get the record at the iterator location
1933 * @iter: The current iterator location
1935 * Returns the record that the current @iter is at.
1937 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
1939 return &iter->pg->records[iter->index];
1943 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1950 if (unlikely(ftrace_disabled))
1953 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1955 ftrace_bug(ret, ip);
1962 * archs can override this function if they must do something
1963 * before the modifying code is performed.
1965 int __weak ftrace_arch_code_modify_prepare(void)
1971 * archs can override this function if they must do something
1972 * after the modifying code is performed.
1974 int __weak ftrace_arch_code_modify_post_process(void)
1979 void ftrace_modify_all_code(int command)
1981 if (command & FTRACE_UPDATE_CALLS)
1982 ftrace_replace_code(1);
1983 else if (command & FTRACE_DISABLE_CALLS)
1984 ftrace_replace_code(0);
1986 if (command & FTRACE_UPDATE_TRACE_FUNC)
1987 ftrace_update_ftrace_func(ftrace_trace_function);
1989 if (command & FTRACE_START_FUNC_RET)
1990 ftrace_enable_ftrace_graph_caller();
1991 else if (command & FTRACE_STOP_FUNC_RET)
1992 ftrace_disable_ftrace_graph_caller();
1995 static int __ftrace_modify_code(void *data)
1997 int *command = data;
1999 ftrace_modify_all_code(*command);
2005 * ftrace_run_stop_machine, go back to the stop machine method
2006 * @command: The command to tell ftrace what to do
2008 * If an arch needs to fall back to the stop machine method, the
2009 * it can call this function.
2011 void ftrace_run_stop_machine(int command)
2013 stop_machine(__ftrace_modify_code, &command, NULL);
2017 * arch_ftrace_update_code, modify the code to trace or not trace
2018 * @command: The command that needs to be done
2020 * Archs can override this function if it does not need to
2021 * run stop_machine() to modify code.
2023 void __weak arch_ftrace_update_code(int command)
2025 ftrace_run_stop_machine(command);
2028 static void ftrace_run_update_code(int command)
2032 ret = ftrace_arch_code_modify_prepare();
2033 FTRACE_WARN_ON(ret);
2037 * Do not call function tracer while we update the code.
2038 * We are in stop machine.
2040 function_trace_stop++;
2043 * By default we use stop_machine() to modify the code.
2044 * But archs can do what ever they want as long as it
2045 * is safe. The stop_machine() is the safest, but also
2046 * produces the most overhead.
2048 arch_ftrace_update_code(command);
2050 function_trace_stop--;
2052 ret = ftrace_arch_code_modify_post_process();
2053 FTRACE_WARN_ON(ret);
2056 static ftrace_func_t saved_ftrace_func;
2057 static int ftrace_start_up;
2058 static int global_start_up;
2060 static void ftrace_startup_enable(int command)
2062 if (saved_ftrace_func != ftrace_trace_function) {
2063 saved_ftrace_func = ftrace_trace_function;
2064 command |= FTRACE_UPDATE_TRACE_FUNC;
2067 if (!command || !ftrace_enabled)
2070 ftrace_run_update_code(command);
2073 static int ftrace_startup(struct ftrace_ops *ops, int command)
2075 bool hash_enable = true;
2077 if (unlikely(ftrace_disabled))
2081 command |= FTRACE_UPDATE_CALLS;
2083 /* ops marked global share the filter hashes */
2084 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
2086 /* Don't update hash if global is already set */
2087 if (global_start_up)
2088 hash_enable = false;
2092 ops->flags |= FTRACE_OPS_FL_ENABLED;
2094 ftrace_hash_rec_enable(ops, 1);
2096 ftrace_startup_enable(command);
2101 static void ftrace_shutdown(struct ftrace_ops *ops, int command)
2103 bool hash_disable = true;
2105 if (unlikely(ftrace_disabled))
2110 * Just warn in case of unbalance, no need to kill ftrace, it's not
2111 * critical but the ftrace_call callers may be never nopped again after
2112 * further ftrace uses.
2114 WARN_ON_ONCE(ftrace_start_up < 0);
2116 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
2119 WARN_ON_ONCE(global_start_up < 0);
2120 /* Don't update hash if global still has users */
2121 if (global_start_up) {
2122 WARN_ON_ONCE(!ftrace_start_up);
2123 hash_disable = false;
2128 ftrace_hash_rec_disable(ops, 1);
2130 if (ops != &global_ops || !global_start_up)
2131 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2133 command |= FTRACE_UPDATE_CALLS;
2135 if (saved_ftrace_func != ftrace_trace_function) {
2136 saved_ftrace_func = ftrace_trace_function;
2137 command |= FTRACE_UPDATE_TRACE_FUNC;
2140 if (!command || !ftrace_enabled)
2143 ftrace_run_update_code(command);
2146 static void ftrace_startup_sysctl(void)
2148 if (unlikely(ftrace_disabled))
2151 /* Force update next time */
2152 saved_ftrace_func = NULL;
2153 /* ftrace_start_up is true if we want ftrace running */
2154 if (ftrace_start_up)
2155 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
2158 static void ftrace_shutdown_sysctl(void)
2160 if (unlikely(ftrace_disabled))
2163 /* ftrace_start_up is true if ftrace is running */
2164 if (ftrace_start_up)
2165 ftrace_run_update_code(FTRACE_DISABLE_CALLS);
2168 static cycle_t ftrace_update_time;
2169 static unsigned long ftrace_update_cnt;
2170 unsigned long ftrace_update_tot_cnt;
2172 static int ops_traces_mod(struct ftrace_ops *ops)
2174 struct ftrace_hash *hash;
2176 hash = ops->filter_hash;
2177 return ftrace_hash_empty(hash);
2180 static int ftrace_update_code(struct module *mod)
2182 struct ftrace_page *pg;
2183 struct dyn_ftrace *p;
2184 cycle_t start, stop;
2185 unsigned long ref = 0;
2189 * When adding a module, we need to check if tracers are
2190 * currently enabled and if they are set to trace all functions.
2191 * If they are, we need to enable the module functions as well
2192 * as update the reference counts for those function records.
2195 struct ftrace_ops *ops;
2197 for (ops = ftrace_ops_list;
2198 ops != &ftrace_list_end; ops = ops->next) {
2199 if (ops->flags & FTRACE_OPS_FL_ENABLED &&
2200 ops_traces_mod(ops))
2205 start = ftrace_now(raw_smp_processor_id());
2206 ftrace_update_cnt = 0;
2208 for (pg = ftrace_new_pgs; pg; pg = pg->next) {
2210 for (i = 0; i < pg->index; i++) {
2211 /* If something went wrong, bail without enabling anything */
2212 if (unlikely(ftrace_disabled))
2215 p = &pg->records[i];
2219 * Do the initial record conversion from mcount jump
2220 * to the NOP instructions.
2222 if (!ftrace_code_disable(mod, p))
2225 ftrace_update_cnt++;
2228 * If the tracing is enabled, go ahead and enable the record.
2230 * The reason not to enable the record immediatelly is the
2231 * inherent check of ftrace_make_nop/ftrace_make_call for
2232 * correct previous instructions. Making first the NOP
2233 * conversion puts the module to the correct state, thus
2234 * passing the ftrace_make_call check.
2236 if (ftrace_start_up && ref) {
2237 int failed = __ftrace_replace_code(p, 1);
2239 ftrace_bug(failed, p->ip);
2244 ftrace_new_pgs = NULL;
2246 stop = ftrace_now(raw_smp_processor_id());
2247 ftrace_update_time = stop - start;
2248 ftrace_update_tot_cnt += ftrace_update_cnt;
2253 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2258 if (WARN_ON(!count))
2261 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2264 * We want to fill as much as possible. No more than a page
2267 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2271 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2274 /* if we can't allocate this size, try something smaller */
2281 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2290 static struct ftrace_page *
2291 ftrace_allocate_pages(unsigned long num_to_init)
2293 struct ftrace_page *start_pg;
2294 struct ftrace_page *pg;
2301 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
2306 * Try to allocate as much as possible in one continues
2307 * location that fills in all of the space. We want to
2308 * waste as little space as possible.
2311 cnt = ftrace_allocate_records(pg, num_to_init);
2319 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
2330 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
2331 free_pages((unsigned long)pg->records, order);
2332 start_pg = pg->next;
2336 pr_info("ftrace: FAILED to allocate memory for functions\n");
2340 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
2345 pr_info("ftrace: No functions to be traced?\n");
2349 cnt = num_to_init / ENTRIES_PER_PAGE;
2350 pr_info("ftrace: allocating %ld entries in %d pages\n",
2351 num_to_init, cnt + 1);
2356 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
2358 struct ftrace_iterator {
2361 struct ftrace_page *pg;
2362 struct dyn_ftrace *func;
2363 struct ftrace_func_probe *probe;
2364 struct trace_parser parser;
2365 struct ftrace_hash *hash;
2366 struct ftrace_ops *ops;
2373 t_hash_next(struct seq_file *m, loff_t *pos)
2375 struct ftrace_iterator *iter = m->private;
2376 struct hlist_node *hnd = NULL;
2377 struct hlist_head *hhd;
2383 hnd = &iter->probe->node;
2385 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
2388 hhd = &ftrace_func_hash[iter->hidx];
2390 if (hlist_empty(hhd)) {
2406 if (WARN_ON_ONCE(!hnd))
2409 iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
2414 static void *t_hash_start(struct seq_file *m, loff_t *pos)
2416 struct ftrace_iterator *iter = m->private;
2420 if (!(iter->flags & FTRACE_ITER_DO_HASH))
2423 if (iter->func_pos > *pos)
2427 for (l = 0; l <= (*pos - iter->func_pos); ) {
2428 p = t_hash_next(m, &l);
2435 /* Only set this if we have an item */
2436 iter->flags |= FTRACE_ITER_HASH;
2442 t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
2444 struct ftrace_func_probe *rec;
2447 if (WARN_ON_ONCE(!rec))
2450 if (rec->ops->print)
2451 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
2453 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
2456 seq_printf(m, ":%p", rec->data);
2463 t_next(struct seq_file *m, void *v, loff_t *pos)
2465 struct ftrace_iterator *iter = m->private;
2466 struct ftrace_ops *ops = iter->ops;
2467 struct dyn_ftrace *rec = NULL;
2469 if (unlikely(ftrace_disabled))
2472 if (iter->flags & FTRACE_ITER_HASH)
2473 return t_hash_next(m, pos);
2476 iter->pos = iter->func_pos = *pos;
2478 if (iter->flags & FTRACE_ITER_PRINTALL)
2479 return t_hash_start(m, pos);
2482 if (iter->idx >= iter->pg->index) {
2483 if (iter->pg->next) {
2484 iter->pg = iter->pg->next;
2489 rec = &iter->pg->records[iter->idx++];
2490 if (((iter->flags & FTRACE_ITER_FILTER) &&
2491 !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||
2493 ((iter->flags & FTRACE_ITER_NOTRACE) &&
2494 !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
2496 ((iter->flags & FTRACE_ITER_ENABLED) &&
2497 !(rec->flags & FTRACE_FL_ENABLED))) {
2505 return t_hash_start(m, pos);
2512 static void reset_iter_read(struct ftrace_iterator *iter)
2516 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_HASH);
2519 static void *t_start(struct seq_file *m, loff_t *pos)
2521 struct ftrace_iterator *iter = m->private;
2522 struct ftrace_ops *ops = iter->ops;
2526 mutex_lock(&ftrace_lock);
2528 if (unlikely(ftrace_disabled))
2532 * If an lseek was done, then reset and start from beginning.
2534 if (*pos < iter->pos)
2535 reset_iter_read(iter);
2538 * For set_ftrace_filter reading, if we have the filter
2539 * off, we can short cut and just print out that all
2540 * functions are enabled.
2542 if (iter->flags & FTRACE_ITER_FILTER &&
2543 ftrace_hash_empty(ops->filter_hash)) {
2545 return t_hash_start(m, pos);
2546 iter->flags |= FTRACE_ITER_PRINTALL;
2547 /* reset in case of seek/pread */
2548 iter->flags &= ~FTRACE_ITER_HASH;
2552 if (iter->flags & FTRACE_ITER_HASH)
2553 return t_hash_start(m, pos);
2556 * Unfortunately, we need to restart at ftrace_pages_start
2557 * every time we let go of the ftrace_mutex. This is because
2558 * those pointers can change without the lock.
2560 iter->pg = ftrace_pages_start;
2562 for (l = 0; l <= *pos; ) {
2563 p = t_next(m, p, &l);
2569 return t_hash_start(m, pos);
2574 static void t_stop(struct seq_file *m, void *p)
2576 mutex_unlock(&ftrace_lock);
2579 static int t_show(struct seq_file *m, void *v)
2581 struct ftrace_iterator *iter = m->private;
2582 struct dyn_ftrace *rec;
2584 if (iter->flags & FTRACE_ITER_HASH)
2585 return t_hash_show(m, iter);
2587 if (iter->flags & FTRACE_ITER_PRINTALL) {
2588 seq_printf(m, "#### all functions enabled ####\n");
2597 seq_printf(m, "%ps", (void *)rec->ip);
2598 if (iter->flags & FTRACE_ITER_ENABLED)
2599 seq_printf(m, " (%ld)%s",
2600 rec->flags & ~FTRACE_FL_MASK,
2601 rec->flags & FTRACE_FL_REGS ? " R" : "");
2602 seq_printf(m, "\n");
2607 static const struct seq_operations show_ftrace_seq_ops = {
2615 ftrace_avail_open(struct inode *inode, struct file *file)
2617 struct ftrace_iterator *iter;
2619 if (unlikely(ftrace_disabled))
2622 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
2624 iter->pg = ftrace_pages_start;
2625 iter->ops = &global_ops;
2628 return iter ? 0 : -ENOMEM;
2632 ftrace_enabled_open(struct inode *inode, struct file *file)
2634 struct ftrace_iterator *iter;
2636 if (unlikely(ftrace_disabled))
2639 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
2641 iter->pg = ftrace_pages_start;
2642 iter->flags = FTRACE_ITER_ENABLED;
2643 iter->ops = &global_ops;
2646 return iter ? 0 : -ENOMEM;
2649 static void ftrace_filter_reset(struct ftrace_hash *hash)
2651 mutex_lock(&ftrace_lock);
2652 ftrace_hash_clear(hash);
2653 mutex_unlock(&ftrace_lock);
2657 * ftrace_regex_open - initialize function tracer filter files
2658 * @ops: The ftrace_ops that hold the hash filters
2659 * @flag: The type of filter to process
2660 * @inode: The inode, usually passed in to your open routine
2661 * @file: The file, usually passed in to your open routine
2663 * ftrace_regex_open() initializes the filter files for the
2664 * @ops. Depending on @flag it may process the filter hash or
2665 * the notrace hash of @ops. With this called from the open
2666 * routine, you can use ftrace_filter_write() for the write
2667 * routine if @flag has FTRACE_ITER_FILTER set, or
2668 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
2669 * ftrace_filter_lseek() should be used as the lseek routine, and
2670 * release must call ftrace_regex_release().
2673 ftrace_regex_open(struct ftrace_ops *ops, int flag,
2674 struct inode *inode, struct file *file)
2676 struct ftrace_iterator *iter;
2677 struct ftrace_hash *hash;
2680 ftrace_ops_init(ops);
2682 if (unlikely(ftrace_disabled))
2685 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2689 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
2697 mutex_lock(&ops->regex_lock);
2699 if (flag & FTRACE_ITER_NOTRACE)
2700 hash = ops->notrace_hash;
2702 hash = ops->filter_hash;
2704 if (file->f_mode & FMODE_WRITE) {
2705 iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
2707 trace_parser_put(&iter->parser);
2714 if ((file->f_mode & FMODE_WRITE) &&
2715 (file->f_flags & O_TRUNC))
2716 ftrace_filter_reset(iter->hash);
2718 if (file->f_mode & FMODE_READ) {
2719 iter->pg = ftrace_pages_start;
2721 ret = seq_open(file, &show_ftrace_seq_ops);
2723 struct seq_file *m = file->private_data;
2727 free_ftrace_hash(iter->hash);
2728 trace_parser_put(&iter->parser);
2732 file->private_data = iter;
2735 mutex_unlock(&ops->regex_lock);
2741 ftrace_filter_open(struct inode *inode, struct file *file)
2743 return ftrace_regex_open(&global_ops,
2744 FTRACE_ITER_FILTER | FTRACE_ITER_DO_HASH,
2749 ftrace_notrace_open(struct inode *inode, struct file *file)
2751 return ftrace_regex_open(&global_ops, FTRACE_ITER_NOTRACE,
2755 static int ftrace_match(char *str, char *regex, int len, int type)
2762 if (strcmp(str, regex) == 0)
2765 case MATCH_FRONT_ONLY:
2766 if (strncmp(str, regex, len) == 0)
2769 case MATCH_MIDDLE_ONLY:
2770 if (strstr(str, regex))
2773 case MATCH_END_ONLY:
2775 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
2784 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
2786 struct ftrace_func_entry *entry;
2789 entry = ftrace_lookup_ip(hash, rec->ip);
2791 /* Do nothing if it doesn't exist */
2795 free_hash_entry(hash, entry);
2797 /* Do nothing if it exists */
2801 ret = add_hash_entry(hash, rec->ip);
2807 ftrace_match_record(struct dyn_ftrace *rec, char *mod,
2808 char *regex, int len, int type)
2810 char str[KSYM_SYMBOL_LEN];
2813 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
2816 /* module lookup requires matching the module */
2817 if (!modname || strcmp(modname, mod))
2820 /* blank search means to match all funcs in the mod */
2825 return ftrace_match(str, regex, len, type);
2829 match_records(struct ftrace_hash *hash, char *buff,
2830 int len, char *mod, int not)
2832 unsigned search_len = 0;
2833 struct ftrace_page *pg;
2834 struct dyn_ftrace *rec;
2835 int type = MATCH_FULL;
2836 char *search = buff;
2841 type = filter_parse_regex(buff, len, &search, ¬);
2842 search_len = strlen(search);
2845 mutex_lock(&ftrace_lock);
2847 if (unlikely(ftrace_disabled))
2850 do_for_each_ftrace_rec(pg, rec) {
2851 if (ftrace_match_record(rec, mod, search, search_len, type)) {
2852 ret = enter_record(hash, rec, not);
2859 } while_for_each_ftrace_rec();
2861 mutex_unlock(&ftrace_lock);
2867 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
2869 return match_records(hash, buff, len, NULL, 0);
2873 ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
2877 /* blank or '*' mean the same */
2878 if (strcmp(buff, "*") == 0)
2881 /* handle the case of 'dont filter this module' */
2882 if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
2887 return match_records(hash, buff, strlen(buff), mod, not);
2891 * We register the module command as a template to show others how
2892 * to register the a command as well.
2896 ftrace_mod_callback(struct ftrace_hash *hash,
2897 char *func, char *cmd, char *param, int enable)
2903 * cmd == 'mod' because we only registered this func
2904 * for the 'mod' ftrace_func_command.
2905 * But if you register one func with multiple commands,
2906 * you can tell which command was used by the cmd
2910 /* we must have a module name */
2914 mod = strsep(¶m, ":");
2918 ret = ftrace_match_module_records(hash, func, mod);
2927 static struct ftrace_func_command ftrace_mod_cmd = {
2929 .func = ftrace_mod_callback,
2932 static int __init ftrace_mod_cmd_init(void)
2934 return register_ftrace_command(&ftrace_mod_cmd);
2936 core_initcall(ftrace_mod_cmd_init);
2938 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
2939 struct ftrace_ops *op, struct pt_regs *pt_regs)
2941 struct ftrace_func_probe *entry;
2942 struct hlist_head *hhd;
2945 key = hash_long(ip, FTRACE_HASH_BITS);
2947 hhd = &ftrace_func_hash[key];
2949 if (hlist_empty(hhd))
2953 * Disable preemption for these calls to prevent a RCU grace
2954 * period. This syncs the hash iteration and freeing of items
2955 * on the hash. rcu_read_lock is too dangerous here.
2957 preempt_disable_notrace();
2958 hlist_for_each_entry_rcu_notrace(entry, hhd, node) {
2959 if (entry->ip == ip)
2960 entry->ops->func(ip, parent_ip, &entry->data);
2962 preempt_enable_notrace();
2965 static struct ftrace_ops trace_probe_ops __read_mostly =
2967 .func = function_trace_probe_call,
2968 .flags = FTRACE_OPS_FL_INITIALIZED,
2969 INIT_REGEX_LOCK(trace_probe_ops)
2972 static int ftrace_probe_registered;
2974 static void __enable_ftrace_function_probe(void)
2979 if (ftrace_probe_registered) {
2980 /* still need to update the function call sites */
2982 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
2986 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2987 struct hlist_head *hhd = &ftrace_func_hash[i];
2991 /* Nothing registered? */
2992 if (i == FTRACE_FUNC_HASHSIZE)
2995 ret = __register_ftrace_function(&trace_probe_ops);
2997 ret = ftrace_startup(&trace_probe_ops, 0);
2999 ftrace_probe_registered = 1;
3002 static void __disable_ftrace_function_probe(void)
3007 if (!ftrace_probe_registered)
3010 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3011 struct hlist_head *hhd = &ftrace_func_hash[i];
3016 /* no more funcs left */
3017 ret = __unregister_ftrace_function(&trace_probe_ops);
3019 ftrace_shutdown(&trace_probe_ops, 0);
3021 ftrace_probe_registered = 0;
3025 static void ftrace_free_entry(struct ftrace_func_probe *entry)
3027 if (entry->ops->free)
3028 entry->ops->free(entry->ops, entry->ip, &entry->data);
3033 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3036 struct ftrace_func_probe *entry;
3037 struct ftrace_hash **orig_hash = &trace_probe_ops.filter_hash;
3038 struct ftrace_hash *hash;
3039 struct ftrace_page *pg;
3040 struct dyn_ftrace *rec;
3047 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
3048 len = strlen(search);
3050 /* we do not support '!' for function probes */
3054 mutex_lock(&trace_probe_ops.regex_lock);
3056 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3062 if (unlikely(ftrace_disabled)) {
3067 mutex_lock(&ftrace_lock);
3069 do_for_each_ftrace_rec(pg, rec) {
3071 if (!ftrace_match_record(rec, NULL, search, len, type))
3074 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
3076 /* If we did not process any, then return error */
3087 * The caller might want to do something special
3088 * for each function we find. We call the callback
3089 * to give the caller an opportunity to do so.
3092 if (ops->init(ops, rec->ip, &entry->data) < 0) {
3093 /* caller does not like this func */
3099 ret = enter_record(hash, rec, 0);
3107 entry->ip = rec->ip;
3109 key = hash_long(entry->ip, FTRACE_HASH_BITS);
3110 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
3112 } while_for_each_ftrace_rec();
3114 ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3118 __enable_ftrace_function_probe();
3121 mutex_unlock(&ftrace_lock);
3123 mutex_unlock(&trace_probe_ops.regex_lock);
3124 free_ftrace_hash(hash);
3130 PROBE_TEST_FUNC = 1,
3135 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3136 void *data, int flags)
3138 struct ftrace_func_entry *rec_entry;
3139 struct ftrace_func_probe *entry;
3140 struct ftrace_func_probe *p;
3141 struct ftrace_hash **orig_hash = &trace_probe_ops.filter_hash;
3142 struct list_head free_list;
3143 struct ftrace_hash *hash;
3144 struct hlist_node *tmp;
3145 char str[KSYM_SYMBOL_LEN];
3146 int type = MATCH_FULL;
3150 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
3155 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
3156 len = strlen(search);
3158 /* we do not support '!' for function probes */
3163 mutex_lock(&trace_probe_ops.regex_lock);
3165 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3167 /* Hmm, should report this somehow */
3170 INIT_LIST_HEAD(&free_list);
3172 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3173 struct hlist_head *hhd = &ftrace_func_hash[i];
3175 hlist_for_each_entry_safe(entry, tmp, hhd, node) {
3177 /* break up if statements for readability */
3178 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
3181 if ((flags & PROBE_TEST_DATA) && entry->data != data)
3184 /* do this last, since it is the most expensive */
3186 kallsyms_lookup(entry->ip, NULL, NULL,
3188 if (!ftrace_match(str, glob, len, type))
3192 rec_entry = ftrace_lookup_ip(hash, entry->ip);
3193 /* It is possible more than one entry had this ip */
3195 free_hash_entry(hash, rec_entry);
3197 hlist_del_rcu(&entry->node);
3198 list_add(&entry->free_list, &free_list);
3201 mutex_lock(&ftrace_lock);
3202 __disable_ftrace_function_probe();
3204 * Remove after the disable is called. Otherwise, if the last
3205 * probe is removed, a null hash means *all enabled*.
3207 ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3208 synchronize_sched();
3209 list_for_each_entry_safe(entry, p, &free_list, free_list) {
3210 list_del(&entry->free_list);
3211 ftrace_free_entry(entry);
3213 mutex_unlock(&ftrace_lock);
3216 mutex_unlock(&trace_probe_ops.regex_lock);
3217 free_ftrace_hash(hash);
3221 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3224 __unregister_ftrace_function_probe(glob, ops, data,
3225 PROBE_TEST_FUNC | PROBE_TEST_DATA);
3229 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
3231 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
3234 void unregister_ftrace_function_probe_all(char *glob)
3236 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
3239 static LIST_HEAD(ftrace_commands);
3240 static DEFINE_MUTEX(ftrace_cmd_mutex);
3242 int register_ftrace_command(struct ftrace_func_command *cmd)
3244 struct ftrace_func_command *p;
3247 mutex_lock(&ftrace_cmd_mutex);
3248 list_for_each_entry(p, &ftrace_commands, list) {
3249 if (strcmp(cmd->name, p->name) == 0) {
3254 list_add(&cmd->list, &ftrace_commands);
3256 mutex_unlock(&ftrace_cmd_mutex);
3261 int unregister_ftrace_command(struct ftrace_func_command *cmd)
3263 struct ftrace_func_command *p, *n;
3266 mutex_lock(&ftrace_cmd_mutex);
3267 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
3268 if (strcmp(cmd->name, p->name) == 0) {
3270 list_del_init(&p->list);
3275 mutex_unlock(&ftrace_cmd_mutex);
3280 static int ftrace_process_regex(struct ftrace_hash *hash,
3281 char *buff, int len, int enable)
3283 char *func, *command, *next = buff;
3284 struct ftrace_func_command *p;
3287 func = strsep(&next, ":");
3290 ret = ftrace_match_records(hash, func, len);
3300 command = strsep(&next, ":");
3302 mutex_lock(&ftrace_cmd_mutex);
3303 list_for_each_entry(p, &ftrace_commands, list) {
3304 if (strcmp(p->name, command) == 0) {
3305 ret = p->func(hash, func, command, next, enable);
3310 mutex_unlock(&ftrace_cmd_mutex);
3316 ftrace_regex_write(struct file *file, const char __user *ubuf,
3317 size_t cnt, loff_t *ppos, int enable)
3319 struct ftrace_iterator *iter;
3320 struct trace_parser *parser;
3326 if (file->f_mode & FMODE_READ) {
3327 struct seq_file *m = file->private_data;
3330 iter = file->private_data;
3332 if (unlikely(ftrace_disabled))
3335 /* iter->hash is a local copy, so we don't need regex_lock */
3337 parser = &iter->parser;
3338 read = trace_get_user(parser, ubuf, cnt, ppos);
3340 if (read >= 0 && trace_parser_loaded(parser) &&
3341 !trace_parser_cont(parser)) {
3342 ret = ftrace_process_regex(iter->hash, parser->buffer,
3343 parser->idx, enable);
3344 trace_parser_clear(parser);
3355 ftrace_filter_write(struct file *file, const char __user *ubuf,
3356 size_t cnt, loff_t *ppos)
3358 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
3362 ftrace_notrace_write(struct file *file, const char __user *ubuf,
3363 size_t cnt, loff_t *ppos)
3365 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
3369 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
3371 struct ftrace_func_entry *entry;
3373 if (!ftrace_location(ip))
3377 entry = ftrace_lookup_ip(hash, ip);
3380 free_hash_entry(hash, entry);
3384 return add_hash_entry(hash, ip);
3388 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
3389 unsigned long ip, int remove, int reset, int enable)
3391 struct ftrace_hash **orig_hash;
3392 struct ftrace_hash *hash;
3395 /* All global ops uses the global ops filters */
3396 if (ops->flags & FTRACE_OPS_FL_GLOBAL)
3399 if (unlikely(ftrace_disabled))
3402 mutex_lock(&ops->regex_lock);
3405 orig_hash = &ops->filter_hash;
3407 orig_hash = &ops->notrace_hash;
3409 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3412 goto out_regex_unlock;
3416 ftrace_filter_reset(hash);
3417 if (buf && !ftrace_match_records(hash, buf, len)) {
3419 goto out_regex_unlock;
3422 ret = ftrace_match_addr(hash, ip, remove);
3424 goto out_regex_unlock;
3427 mutex_lock(&ftrace_lock);
3428 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3429 if (!ret && ops->flags & FTRACE_OPS_FL_ENABLED
3431 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3433 mutex_unlock(&ftrace_lock);
3436 mutex_unlock(&ops->regex_lock);
3438 free_ftrace_hash(hash);
3443 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
3444 int reset, int enable)
3446 return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
3450 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
3451 * @ops - the ops to set the filter with
3452 * @ip - the address to add to or remove from the filter.
3453 * @remove - non zero to remove the ip from the filter
3454 * @reset - non zero to reset all filters before applying this filter.
3456 * Filters denote which functions should be enabled when tracing is enabled
3457 * If @ip is NULL, it failes to update filter.
3459 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
3460 int remove, int reset)
3462 ftrace_ops_init(ops);
3463 return ftrace_set_addr(ops, ip, remove, reset, 1);
3465 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
3468 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
3469 int reset, int enable)
3471 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
3475 * ftrace_set_filter - set a function to filter on in ftrace
3476 * @ops - the ops to set the filter with
3477 * @buf - the string that holds the function filter text.
3478 * @len - the length of the string.
3479 * @reset - non zero to reset all filters before applying this filter.
3481 * Filters denote which functions should be enabled when tracing is enabled.
3482 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3484 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
3487 ftrace_ops_init(ops);
3488 return ftrace_set_regex(ops, buf, len, reset, 1);
3490 EXPORT_SYMBOL_GPL(ftrace_set_filter);
3493 * ftrace_set_notrace - set a function to not trace in ftrace
3494 * @ops - the ops to set the notrace filter with
3495 * @buf - the string that holds the function notrace text.
3496 * @len - the length of the string.
3497 * @reset - non zero to reset all filters before applying this filter.
3499 * Notrace Filters denote which functions should not be enabled when tracing
3500 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3503 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
3506 ftrace_ops_init(ops);
3507 return ftrace_set_regex(ops, buf, len, reset, 0);
3509 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
3511 * ftrace_set_filter - set a function to filter on in ftrace
3512 * @ops - the ops to set the filter with
3513 * @buf - the string that holds the function filter text.
3514 * @len - the length of the string.
3515 * @reset - non zero to reset all filters before applying this filter.
3517 * Filters denote which functions should be enabled when tracing is enabled.
3518 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3520 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
3522 ftrace_set_regex(&global_ops, buf, len, reset, 1);
3524 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
3527 * ftrace_set_notrace - set a function to not trace in ftrace
3528 * @ops - the ops to set the notrace filter with
3529 * @buf - the string that holds the function notrace text.
3530 * @len - the length of the string.
3531 * @reset - non zero to reset all filters before applying this filter.
3533 * Notrace Filters denote which functions should not be enabled when tracing
3534 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3537 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
3539 ftrace_set_regex(&global_ops, buf, len, reset, 0);
3541 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
3544 * command line interface to allow users to set filters on boot up.
3546 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
3547 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
3548 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
3550 /* Used by function selftest to not test if filter is set */
3551 bool ftrace_filter_param __initdata;
3553 static int __init set_ftrace_notrace(char *str)
3555 ftrace_filter_param = true;
3556 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
3559 __setup("ftrace_notrace=", set_ftrace_notrace);
3561 static int __init set_ftrace_filter(char *str)
3563 ftrace_filter_param = true;
3564 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
3567 __setup("ftrace_filter=", set_ftrace_filter);
3569 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3570 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
3571 static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
3573 static int __init set_graph_function(char *str)
3575 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
3578 __setup("ftrace_graph_filter=", set_graph_function);
3580 static void __init set_ftrace_early_graph(char *buf)
3586 func = strsep(&buf, ",");
3587 /* we allow only one expression at a time */
3588 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3591 printk(KERN_DEBUG "ftrace: function %s not "
3592 "traceable\n", func);
3595 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3598 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
3602 ftrace_ops_init(ops);
3605 func = strsep(&buf, ",");
3606 ftrace_set_regex(ops, func, strlen(func), 0, enable);
3610 static void __init set_ftrace_early_filters(void)
3612 if (ftrace_filter_buf[0])
3613 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
3614 if (ftrace_notrace_buf[0])
3615 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
3616 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3617 if (ftrace_graph_buf[0])
3618 set_ftrace_early_graph(ftrace_graph_buf);
3619 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3622 int ftrace_regex_release(struct inode *inode, struct file *file)
3624 struct seq_file *m = (struct seq_file *)file->private_data;
3625 struct ftrace_iterator *iter;
3626 struct ftrace_hash **orig_hash;
3627 struct trace_parser *parser;
3631 if (file->f_mode & FMODE_READ) {
3633 seq_release(inode, file);
3635 iter = file->private_data;
3637 parser = &iter->parser;
3638 if (trace_parser_loaded(parser)) {
3639 parser->buffer[parser->idx] = 0;
3640 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
3643 trace_parser_put(parser);
3645 mutex_lock(&iter->ops->regex_lock);
3647 if (file->f_mode & FMODE_WRITE) {
3648 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
3651 orig_hash = &iter->ops->filter_hash;
3653 orig_hash = &iter->ops->notrace_hash;
3655 mutex_lock(&ftrace_lock);
3656 ret = ftrace_hash_move(iter->ops, filter_hash,
3657 orig_hash, iter->hash);
3658 if (!ret && (iter->ops->flags & FTRACE_OPS_FL_ENABLED)
3660 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3662 mutex_unlock(&ftrace_lock);
3665 mutex_unlock(&iter->ops->regex_lock);
3666 free_ftrace_hash(iter->hash);
3672 static const struct file_operations ftrace_avail_fops = {
3673 .open = ftrace_avail_open,
3675 .llseek = seq_lseek,
3676 .release = seq_release_private,
3679 static const struct file_operations ftrace_enabled_fops = {
3680 .open = ftrace_enabled_open,
3682 .llseek = seq_lseek,
3683 .release = seq_release_private,
3686 static const struct file_operations ftrace_filter_fops = {
3687 .open = ftrace_filter_open,
3689 .write = ftrace_filter_write,
3690 .llseek = ftrace_filter_lseek,
3691 .release = ftrace_regex_release,
3694 static const struct file_operations ftrace_notrace_fops = {
3695 .open = ftrace_notrace_open,
3697 .write = ftrace_notrace_write,
3698 .llseek = ftrace_filter_lseek,
3699 .release = ftrace_regex_release,
3702 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3704 static DEFINE_MUTEX(graph_lock);
3706 int ftrace_graph_count;
3707 int ftrace_graph_filter_enabled;
3708 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
3711 __g_next(struct seq_file *m, loff_t *pos)
3713 if (*pos >= ftrace_graph_count)
3715 return &ftrace_graph_funcs[*pos];
3719 g_next(struct seq_file *m, void *v, loff_t *pos)
3722 return __g_next(m, pos);
3725 static void *g_start(struct seq_file *m, loff_t *pos)
3727 mutex_lock(&graph_lock);
3729 /* Nothing, tell g_show to print all functions are enabled */
3730 if (!ftrace_graph_filter_enabled && !*pos)
3733 return __g_next(m, pos);
3736 static void g_stop(struct seq_file *m, void *p)
3738 mutex_unlock(&graph_lock);
3741 static int g_show(struct seq_file *m, void *v)
3743 unsigned long *ptr = v;
3748 if (ptr == (unsigned long *)1) {
3749 seq_printf(m, "#### all functions enabled ####\n");
3753 seq_printf(m, "%ps\n", (void *)*ptr);
3758 static const struct seq_operations ftrace_graph_seq_ops = {
3766 ftrace_graph_open(struct inode *inode, struct file *file)
3770 if (unlikely(ftrace_disabled))
3773 mutex_lock(&graph_lock);
3774 if ((file->f_mode & FMODE_WRITE) &&
3775 (file->f_flags & O_TRUNC)) {
3776 ftrace_graph_filter_enabled = 0;
3777 ftrace_graph_count = 0;
3778 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
3780 mutex_unlock(&graph_lock);
3782 if (file->f_mode & FMODE_READ)
3783 ret = seq_open(file, &ftrace_graph_seq_ops);
3789 ftrace_graph_release(struct inode *inode, struct file *file)
3791 if (file->f_mode & FMODE_READ)
3792 seq_release(inode, file);
3797 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
3799 struct dyn_ftrace *rec;
3800 struct ftrace_page *pg;
3809 type = filter_parse_regex(buffer, strlen(buffer), &search, ¬);
3810 if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
3813 search_len = strlen(search);
3815 mutex_lock(&ftrace_lock);
3817 if (unlikely(ftrace_disabled)) {
3818 mutex_unlock(&ftrace_lock);
3822 do_for_each_ftrace_rec(pg, rec) {
3824 if (ftrace_match_record(rec, NULL, search, search_len, type)) {
3825 /* if it is in the array */
3827 for (i = 0; i < *idx; i++) {
3828 if (array[i] == rec->ip) {
3837 array[(*idx)++] = rec->ip;
3838 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
3843 array[i] = array[--(*idx)];
3849 } while_for_each_ftrace_rec();
3851 mutex_unlock(&ftrace_lock);
3856 ftrace_graph_filter_enabled = !!(*idx);
3862 ftrace_graph_write(struct file *file, const char __user *ubuf,
3863 size_t cnt, loff_t *ppos)
3865 struct trace_parser parser;
3871 mutex_lock(&graph_lock);
3873 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
3878 read = trace_get_user(&parser, ubuf, cnt, ppos);
3880 if (read >= 0 && trace_parser_loaded((&parser))) {
3881 parser.buffer[parser.idx] = 0;
3883 /* we allow only one expression at a time */
3884 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3893 trace_parser_put(&parser);
3895 mutex_unlock(&graph_lock);
3900 static const struct file_operations ftrace_graph_fops = {
3901 .open = ftrace_graph_open,
3903 .write = ftrace_graph_write,
3904 .llseek = ftrace_filter_lseek,
3905 .release = ftrace_graph_release,
3907 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3909 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
3912 trace_create_file("available_filter_functions", 0444,
3913 d_tracer, NULL, &ftrace_avail_fops);
3915 trace_create_file("enabled_functions", 0444,
3916 d_tracer, NULL, &ftrace_enabled_fops);
3918 trace_create_file("set_ftrace_filter", 0644, d_tracer,
3919 NULL, &ftrace_filter_fops);
3921 trace_create_file("set_ftrace_notrace", 0644, d_tracer,
3922 NULL, &ftrace_notrace_fops);
3924 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3925 trace_create_file("set_graph_function", 0444, d_tracer,
3927 &ftrace_graph_fops);
3928 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3933 static int ftrace_cmp_ips(const void *a, const void *b)
3935 const unsigned long *ipa = a;
3936 const unsigned long *ipb = b;
3945 static void ftrace_swap_ips(void *a, void *b, int size)
3947 unsigned long *ipa = a;
3948 unsigned long *ipb = b;
3956 static int ftrace_process_locs(struct module *mod,
3957 unsigned long *start,
3960 struct ftrace_page *start_pg;
3961 struct ftrace_page *pg;
3962 struct dyn_ftrace *rec;
3963 unsigned long count;
3966 unsigned long flags = 0; /* Shut up gcc */
3969 count = end - start;
3974 sort(start, count, sizeof(*start),
3975 ftrace_cmp_ips, ftrace_swap_ips);
3977 start_pg = ftrace_allocate_pages(count);
3981 mutex_lock(&ftrace_lock);
3984 * Core and each module needs their own pages, as
3985 * modules will free them when they are removed.
3986 * Force a new page to be allocated for modules.
3989 WARN_ON(ftrace_pages || ftrace_pages_start);
3990 /* First initialization */
3991 ftrace_pages = ftrace_pages_start = start_pg;
3996 if (WARN_ON(ftrace_pages->next)) {
3997 /* Hmm, we have free pages? */
3998 while (ftrace_pages->next)
3999 ftrace_pages = ftrace_pages->next;
4002 ftrace_pages->next = start_pg;
4008 addr = ftrace_call_adjust(*p++);
4010 * Some architecture linkers will pad between
4011 * the different mcount_loc sections of different
4012 * object files to satisfy alignments.
4013 * Skip any NULL pointers.
4018 if (pg->index == pg->size) {
4019 /* We should have allocated enough */
4020 if (WARN_ON(!pg->next))
4025 rec = &pg->records[pg->index++];
4029 /* We should have used all pages */
4032 /* Assign the last page to ftrace_pages */
4035 /* These new locations need to be initialized */
4036 ftrace_new_pgs = start_pg;
4039 * We only need to disable interrupts on start up
4040 * because we are modifying code that an interrupt
4041 * may execute, and the modification is not atomic.
4042 * But for modules, nothing runs the code we modify
4043 * until we are finished with it, and there's no
4044 * reason to cause large interrupt latencies while we do it.
4047 local_irq_save(flags);
4048 ftrace_update_code(mod);
4050 local_irq_restore(flags);
4053 mutex_unlock(&ftrace_lock);
4058 #ifdef CONFIG_MODULES
4060 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
4062 void ftrace_release_mod(struct module *mod)
4064 struct dyn_ftrace *rec;
4065 struct ftrace_page **last_pg;
4066 struct ftrace_page *pg;
4069 mutex_lock(&ftrace_lock);
4071 if (ftrace_disabled)
4075 * Each module has its own ftrace_pages, remove
4076 * them from the list.
4078 last_pg = &ftrace_pages_start;
4079 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
4080 rec = &pg->records[0];
4081 if (within_module_core(rec->ip, mod)) {
4083 * As core pages are first, the first
4084 * page should never be a module page.
4086 if (WARN_ON(pg == ftrace_pages_start))
4089 /* Check if we are deleting the last page */
4090 if (pg == ftrace_pages)
4091 ftrace_pages = next_to_ftrace_page(last_pg);
4093 *last_pg = pg->next;
4094 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
4095 free_pages((unsigned long)pg->records, order);
4098 last_pg = &pg->next;
4101 mutex_unlock(&ftrace_lock);
4104 static void ftrace_init_module(struct module *mod,
4105 unsigned long *start, unsigned long *end)
4107 if (ftrace_disabled || start == end)
4109 ftrace_process_locs(mod, start, end);
4112 static int ftrace_module_notify_enter(struct notifier_block *self,
4113 unsigned long val, void *data)
4115 struct module *mod = data;
4117 if (val == MODULE_STATE_COMING)
4118 ftrace_init_module(mod, mod->ftrace_callsites,
4119 mod->ftrace_callsites +
4120 mod->num_ftrace_callsites);
4124 static int ftrace_module_notify_exit(struct notifier_block *self,
4125 unsigned long val, void *data)
4127 struct module *mod = data;
4129 if (val == MODULE_STATE_GOING)
4130 ftrace_release_mod(mod);
4135 static int ftrace_module_notify_enter(struct notifier_block *self,
4136 unsigned long val, void *data)
4140 static int ftrace_module_notify_exit(struct notifier_block *self,
4141 unsigned long val, void *data)
4145 #endif /* CONFIG_MODULES */
4147 struct notifier_block ftrace_module_enter_nb = {
4148 .notifier_call = ftrace_module_notify_enter,
4149 .priority = INT_MAX, /* Run before anything that can use kprobes */
4152 struct notifier_block ftrace_module_exit_nb = {
4153 .notifier_call = ftrace_module_notify_exit,
4154 .priority = INT_MIN, /* Run after anything that can remove kprobes */
4157 extern unsigned long __start_mcount_loc[];
4158 extern unsigned long __stop_mcount_loc[];
4160 void __init ftrace_init(void)
4162 unsigned long count, addr, flags;
4165 /* Keep the ftrace pointer to the stub */
4166 addr = (unsigned long)ftrace_stub;
4168 local_irq_save(flags);
4169 ftrace_dyn_arch_init(&addr);
4170 local_irq_restore(flags);
4172 /* ftrace_dyn_arch_init places the return code in addr */
4176 count = __stop_mcount_loc - __start_mcount_loc;
4178 ret = ftrace_dyn_table_alloc(count);
4182 last_ftrace_enabled = ftrace_enabled = 1;
4184 ret = ftrace_process_locs(NULL,
4188 ret = register_module_notifier(&ftrace_module_enter_nb);
4190 pr_warning("Failed to register trace ftrace module enter notifier\n");
4192 ret = register_module_notifier(&ftrace_module_exit_nb);
4194 pr_warning("Failed to register trace ftrace module exit notifier\n");
4196 set_ftrace_early_filters();
4200 ftrace_disabled = 1;
4205 static struct ftrace_ops global_ops = {
4206 .func = ftrace_stub,
4207 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
4208 INIT_REGEX_LOCK(global_ops)
4211 static int __init ftrace_nodyn_init(void)
4216 core_initcall(ftrace_nodyn_init);
4218 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
4219 static inline void ftrace_startup_enable(int command) { }
4220 /* Keep as macros so we do not need to define the commands */
4221 # define ftrace_startup(ops, command) \
4223 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
4226 # define ftrace_shutdown(ops, command) do { } while (0)
4227 # define ftrace_startup_sysctl() do { } while (0)
4228 # define ftrace_shutdown_sysctl() do { } while (0)
4231 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
4236 #endif /* CONFIG_DYNAMIC_FTRACE */
4239 ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
4240 struct ftrace_ops *op, struct pt_regs *regs)
4242 if (unlikely(trace_recursion_test(TRACE_CONTROL_BIT)))
4246 * Some of the ops may be dynamically allocated,
4247 * they must be freed after a synchronize_sched().
4249 preempt_disable_notrace();
4250 trace_recursion_set(TRACE_CONTROL_BIT);
4251 do_for_each_ftrace_op(op, ftrace_control_list) {
4252 if (!(op->flags & FTRACE_OPS_FL_STUB) &&
4253 !ftrace_function_local_disabled(op) &&
4254 ftrace_ops_test(op, ip, regs))
4255 op->func(ip, parent_ip, op, regs);
4256 } while_for_each_ftrace_op(op);
4257 trace_recursion_clear(TRACE_CONTROL_BIT);
4258 preempt_enable_notrace();
4261 static struct ftrace_ops control_ops = {
4262 .func = ftrace_ops_control_func,
4263 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
4264 INIT_REGEX_LOCK(control_ops)
4268 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
4269 struct ftrace_ops *ignored, struct pt_regs *regs)
4271 struct ftrace_ops *op;
4274 if (function_trace_stop)
4277 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
4282 * Some of the ops may be dynamically allocated,
4283 * they must be freed after a synchronize_sched().
4285 preempt_disable_notrace();
4286 do_for_each_ftrace_op(op, ftrace_ops_list) {
4287 if (ftrace_ops_test(op, ip, regs))
4288 op->func(ip, parent_ip, op, regs);
4289 } while_for_each_ftrace_op(op);
4290 preempt_enable_notrace();
4291 trace_clear_recursion(bit);
4295 * Some archs only support passing ip and parent_ip. Even though
4296 * the list function ignores the op parameter, we do not want any
4297 * C side effects, where a function is called without the caller
4298 * sending a third parameter.
4299 * Archs are to support both the regs and ftrace_ops at the same time.
4300 * If they support ftrace_ops, it is assumed they support regs.
4301 * If call backs want to use regs, they must either check for regs
4302 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
4303 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
4304 * An architecture can pass partial regs with ftrace_ops and still
4305 * set the ARCH_SUPPORT_FTARCE_OPS.
4307 #if ARCH_SUPPORTS_FTRACE_OPS
4308 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
4309 struct ftrace_ops *op, struct pt_regs *regs)
4311 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
4314 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
4316 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
4320 static void clear_ftrace_swapper(void)
4322 struct task_struct *p;
4326 for_each_online_cpu(cpu) {
4328 clear_tsk_trace_trace(p);
4333 static void set_ftrace_swapper(void)
4335 struct task_struct *p;
4339 for_each_online_cpu(cpu) {
4341 set_tsk_trace_trace(p);
4346 static void clear_ftrace_pid(struct pid *pid)
4348 struct task_struct *p;
4351 do_each_pid_task(pid, PIDTYPE_PID, p) {
4352 clear_tsk_trace_trace(p);
4353 } while_each_pid_task(pid, PIDTYPE_PID, p);
4359 static void set_ftrace_pid(struct pid *pid)
4361 struct task_struct *p;
4364 do_each_pid_task(pid, PIDTYPE_PID, p) {
4365 set_tsk_trace_trace(p);
4366 } while_each_pid_task(pid, PIDTYPE_PID, p);
4370 static void clear_ftrace_pid_task(struct pid *pid)
4372 if (pid == ftrace_swapper_pid)
4373 clear_ftrace_swapper();
4375 clear_ftrace_pid(pid);
4378 static void set_ftrace_pid_task(struct pid *pid)
4380 if (pid == ftrace_swapper_pid)
4381 set_ftrace_swapper();
4383 set_ftrace_pid(pid);
4386 static int ftrace_pid_add(int p)
4389 struct ftrace_pid *fpid;
4392 mutex_lock(&ftrace_lock);
4395 pid = ftrace_swapper_pid;
4397 pid = find_get_pid(p);
4404 list_for_each_entry(fpid, &ftrace_pids, list)
4405 if (fpid->pid == pid)
4410 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
4414 list_add(&fpid->list, &ftrace_pids);
4417 set_ftrace_pid_task(pid);
4419 ftrace_update_pid_func();
4420 ftrace_startup_enable(0);
4422 mutex_unlock(&ftrace_lock);
4426 if (pid != ftrace_swapper_pid)
4430 mutex_unlock(&ftrace_lock);
4434 static void ftrace_pid_reset(void)
4436 struct ftrace_pid *fpid, *safe;
4438 mutex_lock(&ftrace_lock);
4439 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
4440 struct pid *pid = fpid->pid;
4442 clear_ftrace_pid_task(pid);
4444 list_del(&fpid->list);
4448 ftrace_update_pid_func();
4449 ftrace_startup_enable(0);
4451 mutex_unlock(&ftrace_lock);
4454 static void *fpid_start(struct seq_file *m, loff_t *pos)
4456 mutex_lock(&ftrace_lock);
4458 if (list_empty(&ftrace_pids) && (!*pos))
4461 return seq_list_start(&ftrace_pids, *pos);
4464 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
4469 return seq_list_next(v, &ftrace_pids, pos);
4472 static void fpid_stop(struct seq_file *m, void *p)
4474 mutex_unlock(&ftrace_lock);
4477 static int fpid_show(struct seq_file *m, void *v)
4479 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
4481 if (v == (void *)1) {
4482 seq_printf(m, "no pid\n");
4486 if (fpid->pid == ftrace_swapper_pid)
4487 seq_printf(m, "swapper tasks\n");
4489 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
4494 static const struct seq_operations ftrace_pid_sops = {
4495 .start = fpid_start,
4502 ftrace_pid_open(struct inode *inode, struct file *file)
4506 if ((file->f_mode & FMODE_WRITE) &&
4507 (file->f_flags & O_TRUNC))
4510 if (file->f_mode & FMODE_READ)
4511 ret = seq_open(file, &ftrace_pid_sops);
4517 ftrace_pid_write(struct file *filp, const char __user *ubuf,
4518 size_t cnt, loff_t *ppos)
4524 if (cnt >= sizeof(buf))
4527 if (copy_from_user(&buf, ubuf, cnt))
4533 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
4534 * to clean the filter quietly.
4536 tmp = strstrip(buf);
4537 if (strlen(tmp) == 0)
4540 ret = kstrtol(tmp, 10, &val);
4544 ret = ftrace_pid_add(val);
4546 return ret ? ret : cnt;
4550 ftrace_pid_release(struct inode *inode, struct file *file)
4552 if (file->f_mode & FMODE_READ)
4553 seq_release(inode, file);
4558 static const struct file_operations ftrace_pid_fops = {
4559 .open = ftrace_pid_open,
4560 .write = ftrace_pid_write,
4562 .llseek = ftrace_filter_lseek,
4563 .release = ftrace_pid_release,
4566 static __init int ftrace_init_debugfs(void)
4568 struct dentry *d_tracer;
4570 d_tracer = tracing_init_dentry();
4574 ftrace_init_dyn_debugfs(d_tracer);
4576 trace_create_file("set_ftrace_pid", 0644, d_tracer,
4577 NULL, &ftrace_pid_fops);
4579 ftrace_profile_debugfs(d_tracer);
4583 fs_initcall(ftrace_init_debugfs);
4586 * ftrace_kill - kill ftrace
4588 * This function should be used by panic code. It stops ftrace
4589 * but in a not so nice way. If you need to simply kill ftrace
4590 * from a non-atomic section, use ftrace_kill.
4592 void ftrace_kill(void)
4594 ftrace_disabled = 1;
4596 clear_ftrace_function();
4600 * Test if ftrace is dead or not.
4602 int ftrace_is_dead(void)
4604 return ftrace_disabled;
4608 * register_ftrace_function - register a function for profiling
4609 * @ops - ops structure that holds the function for profiling.
4611 * Register a function to be called by all functions in the
4614 * Note: @ops->func and all the functions it calls must be labeled
4615 * with "notrace", otherwise it will go into a
4618 int register_ftrace_function(struct ftrace_ops *ops)
4622 ftrace_ops_init(ops);
4624 mutex_lock(&ftrace_lock);
4626 ret = __register_ftrace_function(ops);
4628 ret = ftrace_startup(ops, 0);
4630 mutex_unlock(&ftrace_lock);
4634 EXPORT_SYMBOL_GPL(register_ftrace_function);
4637 * unregister_ftrace_function - unregister a function for profiling.
4638 * @ops - ops structure that holds the function to unregister
4640 * Unregister a function that was added to be called by ftrace profiling.
4642 int unregister_ftrace_function(struct ftrace_ops *ops)
4646 mutex_lock(&ftrace_lock);
4647 ret = __unregister_ftrace_function(ops);
4649 ftrace_shutdown(ops, 0);
4650 mutex_unlock(&ftrace_lock);
4654 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
4657 ftrace_enable_sysctl(struct ctl_table *table, int write,
4658 void __user *buffer, size_t *lenp,
4663 mutex_lock(&ftrace_lock);
4665 if (unlikely(ftrace_disabled))
4668 ret = proc_dointvec(table, write, buffer, lenp, ppos);
4670 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
4673 last_ftrace_enabled = !!ftrace_enabled;
4675 if (ftrace_enabled) {
4677 ftrace_startup_sysctl();
4679 /* we are starting ftrace again */
4680 if (ftrace_ops_list != &ftrace_list_end)
4681 update_ftrace_function();
4684 /* stopping ftrace calls (just send to ftrace_stub) */
4685 ftrace_trace_function = ftrace_stub;
4687 ftrace_shutdown_sysctl();
4691 mutex_unlock(&ftrace_lock);
4695 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4697 static int ftrace_graph_active;
4698 static struct notifier_block ftrace_suspend_notifier;
4700 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
4705 /* The callbacks that hook a function */
4706 trace_func_graph_ret_t ftrace_graph_return =
4707 (trace_func_graph_ret_t)ftrace_stub;
4708 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
4710 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
4711 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
4715 unsigned long flags;
4716 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
4717 struct task_struct *g, *t;
4719 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
4720 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
4721 * sizeof(struct ftrace_ret_stack),
4723 if (!ret_stack_list[i]) {
4731 read_lock_irqsave(&tasklist_lock, flags);
4732 do_each_thread(g, t) {
4738 if (t->ret_stack == NULL) {
4739 atomic_set(&t->tracing_graph_pause, 0);
4740 atomic_set(&t->trace_overrun, 0);
4741 t->curr_ret_stack = -1;
4742 /* Make sure the tasks see the -1 first: */
4744 t->ret_stack = ret_stack_list[start++];
4746 } while_each_thread(g, t);
4749 read_unlock_irqrestore(&tasklist_lock, flags);
4751 for (i = start; i < end; i++)
4752 kfree(ret_stack_list[i]);
4757 ftrace_graph_probe_sched_switch(void *ignore,
4758 struct task_struct *prev, struct task_struct *next)
4760 unsigned long long timestamp;
4764 * Does the user want to count the time a function was asleep.
4765 * If so, do not update the time stamps.
4767 if (trace_flags & TRACE_ITER_SLEEP_TIME)
4770 timestamp = trace_clock_local();
4772 prev->ftrace_timestamp = timestamp;
4774 /* only process tasks that we timestamped */
4775 if (!next->ftrace_timestamp)
4779 * Update all the counters in next to make up for the
4780 * time next was sleeping.
4782 timestamp -= next->ftrace_timestamp;
4784 for (index = next->curr_ret_stack; index >= 0; index--)
4785 next->ret_stack[index].calltime += timestamp;
4788 /* Allocate a return stack for each task */
4789 static int start_graph_tracing(void)
4791 struct ftrace_ret_stack **ret_stack_list;
4794 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
4795 sizeof(struct ftrace_ret_stack *),
4798 if (!ret_stack_list)
4801 /* The cpu_boot init_task->ret_stack will never be freed */
4802 for_each_online_cpu(cpu) {
4803 if (!idle_task(cpu)->ret_stack)
4804 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
4808 ret = alloc_retstack_tasklist(ret_stack_list);
4809 } while (ret == -EAGAIN);
4812 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4814 pr_info("ftrace_graph: Couldn't activate tracepoint"
4815 " probe to kernel_sched_switch\n");
4818 kfree(ret_stack_list);
4823 * Hibernation protection.
4824 * The state of the current task is too much unstable during
4825 * suspend/restore to disk. We want to protect against that.
4828 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
4832 case PM_HIBERNATION_PREPARE:
4833 pause_graph_tracing();
4836 case PM_POST_HIBERNATION:
4837 unpause_graph_tracing();
4843 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
4844 trace_func_graph_ent_t entryfunc)
4848 mutex_lock(&ftrace_lock);
4850 /* we currently allow only one tracer registered at a time */
4851 if (ftrace_graph_active) {
4856 ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
4857 register_pm_notifier(&ftrace_suspend_notifier);
4859 ftrace_graph_active++;
4860 ret = start_graph_tracing();
4862 ftrace_graph_active--;
4866 ftrace_graph_return = retfunc;
4867 ftrace_graph_entry = entryfunc;
4869 ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET);
4872 mutex_unlock(&ftrace_lock);
4876 void unregister_ftrace_graph(void)
4878 mutex_lock(&ftrace_lock);
4880 if (unlikely(!ftrace_graph_active))
4883 ftrace_graph_active--;
4884 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
4885 ftrace_graph_entry = ftrace_graph_entry_stub;
4886 ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET);
4887 unregister_pm_notifier(&ftrace_suspend_notifier);
4888 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4891 mutex_unlock(&ftrace_lock);
4894 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
4897 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
4899 atomic_set(&t->tracing_graph_pause, 0);
4900 atomic_set(&t->trace_overrun, 0);
4901 t->ftrace_timestamp = 0;
4902 /* make curr_ret_stack visible before we add the ret_stack */
4904 t->ret_stack = ret_stack;
4908 * Allocate a return stack for the idle task. May be the first
4909 * time through, or it may be done by CPU hotplug online.
4911 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
4913 t->curr_ret_stack = -1;
4915 * The idle task has no parent, it either has its own
4916 * stack or no stack at all.
4919 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
4921 if (ftrace_graph_active) {
4922 struct ftrace_ret_stack *ret_stack;
4924 ret_stack = per_cpu(idle_ret_stack, cpu);
4926 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4927 * sizeof(struct ftrace_ret_stack),
4931 per_cpu(idle_ret_stack, cpu) = ret_stack;
4933 graph_init_task(t, ret_stack);
4937 /* Allocate a return stack for newly created task */
4938 void ftrace_graph_init_task(struct task_struct *t)
4940 /* Make sure we do not use the parent ret_stack */
4941 t->ret_stack = NULL;
4942 t->curr_ret_stack = -1;
4944 if (ftrace_graph_active) {
4945 struct ftrace_ret_stack *ret_stack;
4947 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4948 * sizeof(struct ftrace_ret_stack),
4952 graph_init_task(t, ret_stack);
4956 void ftrace_graph_exit_task(struct task_struct *t)
4958 struct ftrace_ret_stack *ret_stack = t->ret_stack;
4960 t->ret_stack = NULL;
4961 /* NULL must become visible to IRQs before we free it: */
4967 void ftrace_graph_stop(void)