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 int __unregister_ftrace_function(struct ftrace_ops *ops)
423 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
426 if (FTRACE_WARN_ON(ops == &global_ops))
429 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
430 ret = remove_ftrace_list_ops(&ftrace_global_list,
433 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
434 } else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
435 ret = remove_ftrace_list_ops(&ftrace_control_list,
439 * The ftrace_ops is now removed from the list,
440 * so there'll be no new users. We must ensure
441 * all current users are done before we free
445 control_ops_free(ops);
448 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
454 update_ftrace_function();
457 * Dynamic ops may be freed, we must make sure that all
458 * callers are done before leaving this function.
460 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
466 static void ftrace_update_pid_func(void)
468 /* Only do something if we are tracing something */
469 if (ftrace_trace_function == ftrace_stub)
472 update_ftrace_function();
475 #ifdef CONFIG_FUNCTION_PROFILER
476 struct ftrace_profile {
477 struct hlist_node node;
479 unsigned long counter;
480 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
481 unsigned long long time;
482 unsigned long long time_squared;
486 struct ftrace_profile_page {
487 struct ftrace_profile_page *next;
489 struct ftrace_profile records[];
492 struct ftrace_profile_stat {
494 struct hlist_head *hash;
495 struct ftrace_profile_page *pages;
496 struct ftrace_profile_page *start;
497 struct tracer_stat stat;
500 #define PROFILE_RECORDS_SIZE \
501 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
503 #define PROFILES_PER_PAGE \
504 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
506 static int ftrace_profile_enabled __read_mostly;
508 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
509 static DEFINE_MUTEX(ftrace_profile_lock);
511 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
513 #define FTRACE_PROFILE_HASH_BITS 10
514 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
517 function_stat_next(void *v, int idx)
519 struct ftrace_profile *rec = v;
520 struct ftrace_profile_page *pg;
522 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
528 if ((void *)rec >= (void *)&pg->records[pg->index]) {
532 rec = &pg->records[0];
540 static void *function_stat_start(struct tracer_stat *trace)
542 struct ftrace_profile_stat *stat =
543 container_of(trace, struct ftrace_profile_stat, stat);
545 if (!stat || !stat->start)
548 return function_stat_next(&stat->start->records[0], 0);
551 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
552 /* function graph compares on total time */
553 static int function_stat_cmp(void *p1, void *p2)
555 struct ftrace_profile *a = p1;
556 struct ftrace_profile *b = p2;
558 if (a->time < b->time)
560 if (a->time > b->time)
566 /* not function graph compares against hits */
567 static int function_stat_cmp(void *p1, void *p2)
569 struct ftrace_profile *a = p1;
570 struct ftrace_profile *b = p2;
572 if (a->counter < b->counter)
574 if (a->counter > b->counter)
581 static int function_stat_headers(struct seq_file *m)
583 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
584 seq_printf(m, " Function "
587 "--- ---- --- ---\n");
589 seq_printf(m, " Function Hit\n"
595 static int function_stat_show(struct seq_file *m, void *v)
597 struct ftrace_profile *rec = v;
598 char str[KSYM_SYMBOL_LEN];
600 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
601 static struct trace_seq s;
602 unsigned long long avg;
603 unsigned long long stddev;
605 mutex_lock(&ftrace_profile_lock);
607 /* we raced with function_profile_reset() */
608 if (unlikely(rec->counter == 0)) {
613 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
614 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
616 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
619 do_div(avg, rec->counter);
621 /* Sample standard deviation (s^2) */
622 if (rec->counter <= 1)
625 stddev = rec->time_squared - rec->counter * avg * avg;
627 * Divide only 1000 for ns^2 -> us^2 conversion.
628 * trace_print_graph_duration will divide 1000 again.
630 do_div(stddev, (rec->counter - 1) * 1000);
634 trace_print_graph_duration(rec->time, &s);
635 trace_seq_puts(&s, " ");
636 trace_print_graph_duration(avg, &s);
637 trace_seq_puts(&s, " ");
638 trace_print_graph_duration(stddev, &s);
639 trace_print_seq(m, &s);
643 mutex_unlock(&ftrace_profile_lock);
648 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
650 struct ftrace_profile_page *pg;
652 pg = stat->pages = stat->start;
655 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
660 memset(stat->hash, 0,
661 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
664 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
666 struct ftrace_profile_page *pg;
671 /* If we already allocated, do nothing */
675 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
679 #ifdef CONFIG_DYNAMIC_FTRACE
680 functions = ftrace_update_tot_cnt;
683 * We do not know the number of functions that exist because
684 * dynamic tracing is what counts them. With past experience
685 * we have around 20K functions. That should be more than enough.
686 * It is highly unlikely we will execute every function in
692 pg = stat->start = stat->pages;
694 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
696 for (i = 1; i < pages; i++) {
697 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
708 unsigned long tmp = (unsigned long)pg;
720 static int ftrace_profile_init_cpu(int cpu)
722 struct ftrace_profile_stat *stat;
725 stat = &per_cpu(ftrace_profile_stats, cpu);
728 /* If the profile is already created, simply reset it */
729 ftrace_profile_reset(stat);
734 * We are profiling all functions, but usually only a few thousand
735 * functions are hit. We'll make a hash of 1024 items.
737 size = FTRACE_PROFILE_HASH_SIZE;
739 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
744 /* Preallocate the function profiling pages */
745 if (ftrace_profile_pages_init(stat) < 0) {
754 static int ftrace_profile_init(void)
759 for_each_online_cpu(cpu) {
760 ret = ftrace_profile_init_cpu(cpu);
768 /* interrupts must be disabled */
769 static struct ftrace_profile *
770 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
772 struct ftrace_profile *rec;
773 struct hlist_head *hhd;
776 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
777 hhd = &stat->hash[key];
779 if (hlist_empty(hhd))
782 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
790 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
791 struct ftrace_profile *rec)
795 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
796 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
800 * The memory is already allocated, this simply finds a new record to use.
802 static struct ftrace_profile *
803 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
805 struct ftrace_profile *rec = NULL;
807 /* prevent recursion (from NMIs) */
808 if (atomic_inc_return(&stat->disabled) != 1)
812 * Try to find the function again since an NMI
813 * could have added it
815 rec = ftrace_find_profiled_func(stat, ip);
819 if (stat->pages->index == PROFILES_PER_PAGE) {
820 if (!stat->pages->next)
822 stat->pages = stat->pages->next;
825 rec = &stat->pages->records[stat->pages->index++];
827 ftrace_add_profile(stat, rec);
830 atomic_dec(&stat->disabled);
836 function_profile_call(unsigned long ip, unsigned long parent_ip,
837 struct ftrace_ops *ops, struct pt_regs *regs)
839 struct ftrace_profile_stat *stat;
840 struct ftrace_profile *rec;
843 if (!ftrace_profile_enabled)
846 local_irq_save(flags);
848 stat = &__get_cpu_var(ftrace_profile_stats);
849 if (!stat->hash || !ftrace_profile_enabled)
852 rec = ftrace_find_profiled_func(stat, ip);
854 rec = ftrace_profile_alloc(stat, ip);
861 local_irq_restore(flags);
864 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
865 static int profile_graph_entry(struct ftrace_graph_ent *trace)
867 function_profile_call(trace->func, 0, NULL, NULL);
871 static void profile_graph_return(struct ftrace_graph_ret *trace)
873 struct ftrace_profile_stat *stat;
874 unsigned long long calltime;
875 struct ftrace_profile *rec;
878 local_irq_save(flags);
879 stat = &__get_cpu_var(ftrace_profile_stats);
880 if (!stat->hash || !ftrace_profile_enabled)
883 /* If the calltime was zero'd ignore it */
884 if (!trace->calltime)
887 calltime = trace->rettime - trace->calltime;
889 if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
892 index = trace->depth;
894 /* Append this call time to the parent time to subtract */
896 current->ret_stack[index - 1].subtime += calltime;
898 if (current->ret_stack[index].subtime < calltime)
899 calltime -= current->ret_stack[index].subtime;
904 rec = ftrace_find_profiled_func(stat, trace->func);
906 rec->time += calltime;
907 rec->time_squared += calltime * calltime;
911 local_irq_restore(flags);
914 static int register_ftrace_profiler(void)
916 return register_ftrace_graph(&profile_graph_return,
917 &profile_graph_entry);
920 static void unregister_ftrace_profiler(void)
922 unregister_ftrace_graph();
925 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
926 .func = function_profile_call,
927 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
928 INIT_REGEX_LOCK(ftrace_profile_ops)
931 static int register_ftrace_profiler(void)
933 return register_ftrace_function(&ftrace_profile_ops);
936 static void unregister_ftrace_profiler(void)
938 unregister_ftrace_function(&ftrace_profile_ops);
940 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
943 ftrace_profile_write(struct file *filp, const char __user *ubuf,
944 size_t cnt, loff_t *ppos)
949 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
955 mutex_lock(&ftrace_profile_lock);
956 if (ftrace_profile_enabled ^ val) {
958 ret = ftrace_profile_init();
964 ret = register_ftrace_profiler();
969 ftrace_profile_enabled = 1;
971 ftrace_profile_enabled = 0;
973 * unregister_ftrace_profiler calls stop_machine
974 * so this acts like an synchronize_sched.
976 unregister_ftrace_profiler();
980 mutex_unlock(&ftrace_profile_lock);
988 ftrace_profile_read(struct file *filp, char __user *ubuf,
989 size_t cnt, loff_t *ppos)
991 char buf[64]; /* big enough to hold a number */
994 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
995 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
998 static const struct file_operations ftrace_profile_fops = {
999 .open = tracing_open_generic,
1000 .read = ftrace_profile_read,
1001 .write = ftrace_profile_write,
1002 .llseek = default_llseek,
1005 /* used to initialize the real stat files */
1006 static struct tracer_stat function_stats __initdata = {
1007 .name = "functions",
1008 .stat_start = function_stat_start,
1009 .stat_next = function_stat_next,
1010 .stat_cmp = function_stat_cmp,
1011 .stat_headers = function_stat_headers,
1012 .stat_show = function_stat_show
1015 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
1017 struct ftrace_profile_stat *stat;
1018 struct dentry *entry;
1023 for_each_possible_cpu(cpu) {
1024 stat = &per_cpu(ftrace_profile_stats, cpu);
1026 /* allocate enough for function name + cpu number */
1027 name = kmalloc(32, GFP_KERNEL);
1030 * The files created are permanent, if something happens
1031 * we still do not free memory.
1034 "Could not allocate stat file for cpu %d\n",
1038 stat->stat = function_stats;
1039 snprintf(name, 32, "function%d", cpu);
1040 stat->stat.name = name;
1041 ret = register_stat_tracer(&stat->stat);
1044 "Could not register function stat for cpu %d\n",
1051 entry = debugfs_create_file("function_profile_enabled", 0644,
1052 d_tracer, NULL, &ftrace_profile_fops);
1054 pr_warning("Could not create debugfs "
1055 "'function_profile_enabled' entry\n");
1058 #else /* CONFIG_FUNCTION_PROFILER */
1059 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
1062 #endif /* CONFIG_FUNCTION_PROFILER */
1064 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1067 ftrace_filter_lseek(struct file *file, loff_t offset, int whence)
1071 if (file->f_mode & FMODE_READ)
1072 ret = seq_lseek(file, offset, whence);
1074 file->f_pos = ret = 1;
1079 #ifdef CONFIG_DYNAMIC_FTRACE
1081 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1082 # error Dynamic ftrace depends on MCOUNT_RECORD
1085 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
1087 struct ftrace_func_probe {
1088 struct hlist_node node;
1089 struct ftrace_probe_ops *ops;
1090 unsigned long flags;
1093 struct list_head free_list;
1096 struct ftrace_func_entry {
1097 struct hlist_node hlist;
1101 struct ftrace_hash {
1102 unsigned long size_bits;
1103 struct hlist_head *buckets;
1104 unsigned long count;
1105 struct rcu_head rcu;
1109 * We make these constant because no one should touch them,
1110 * but they are used as the default "empty hash", to avoid allocating
1111 * it all the time. These are in a read only section such that if
1112 * anyone does try to modify it, it will cause an exception.
1114 static const struct hlist_head empty_buckets[1];
1115 static const struct ftrace_hash empty_hash = {
1116 .buckets = (struct hlist_head *)empty_buckets,
1118 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1120 static struct ftrace_ops global_ops = {
1121 .func = ftrace_stub,
1122 .notrace_hash = EMPTY_HASH,
1123 .filter_hash = EMPTY_HASH,
1124 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
1125 INIT_REGEX_LOCK(global_ops)
1128 struct ftrace_page {
1129 struct ftrace_page *next;
1130 struct dyn_ftrace *records;
1135 static struct ftrace_page *ftrace_new_pgs;
1137 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1138 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1140 /* estimate from running different kernels */
1141 #define NR_TO_INIT 10000
1143 static struct ftrace_page *ftrace_pages_start;
1144 static struct ftrace_page *ftrace_pages;
1146 static bool ftrace_hash_empty(struct ftrace_hash *hash)
1148 return !hash || !hash->count;
1151 static struct ftrace_func_entry *
1152 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1155 struct ftrace_func_entry *entry;
1156 struct hlist_head *hhd;
1158 if (ftrace_hash_empty(hash))
1161 if (hash->size_bits > 0)
1162 key = hash_long(ip, hash->size_bits);
1166 hhd = &hash->buckets[key];
1168 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1169 if (entry->ip == ip)
1175 static void __add_hash_entry(struct ftrace_hash *hash,
1176 struct ftrace_func_entry *entry)
1178 struct hlist_head *hhd;
1181 if (hash->size_bits)
1182 key = hash_long(entry->ip, hash->size_bits);
1186 hhd = &hash->buckets[key];
1187 hlist_add_head(&entry->hlist, hhd);
1191 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1193 struct ftrace_func_entry *entry;
1195 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1200 __add_hash_entry(hash, entry);
1206 free_hash_entry(struct ftrace_hash *hash,
1207 struct ftrace_func_entry *entry)
1209 hlist_del(&entry->hlist);
1215 remove_hash_entry(struct ftrace_hash *hash,
1216 struct ftrace_func_entry *entry)
1218 hlist_del(&entry->hlist);
1222 static void ftrace_hash_clear(struct ftrace_hash *hash)
1224 struct hlist_head *hhd;
1225 struct hlist_node *tn;
1226 struct ftrace_func_entry *entry;
1227 int size = 1 << hash->size_bits;
1233 for (i = 0; i < size; i++) {
1234 hhd = &hash->buckets[i];
1235 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1236 free_hash_entry(hash, entry);
1238 FTRACE_WARN_ON(hash->count);
1241 static void free_ftrace_hash(struct ftrace_hash *hash)
1243 if (!hash || hash == EMPTY_HASH)
1245 ftrace_hash_clear(hash);
1246 kfree(hash->buckets);
1250 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1252 struct ftrace_hash *hash;
1254 hash = container_of(rcu, struct ftrace_hash, rcu);
1255 free_ftrace_hash(hash);
1258 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1260 if (!hash || hash == EMPTY_HASH)
1262 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1265 void ftrace_free_filter(struct ftrace_ops *ops)
1267 ftrace_ops_init(ops);
1268 free_ftrace_hash(ops->filter_hash);
1269 free_ftrace_hash(ops->notrace_hash);
1272 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1274 struct ftrace_hash *hash;
1277 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1281 size = 1 << size_bits;
1282 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1284 if (!hash->buckets) {
1289 hash->size_bits = size_bits;
1294 static struct ftrace_hash *
1295 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1297 struct ftrace_func_entry *entry;
1298 struct ftrace_hash *new_hash;
1303 new_hash = alloc_ftrace_hash(size_bits);
1308 if (ftrace_hash_empty(hash))
1311 size = 1 << hash->size_bits;
1312 for (i = 0; i < size; i++) {
1313 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1314 ret = add_hash_entry(new_hash, entry->ip);
1320 FTRACE_WARN_ON(new_hash->count != hash->count);
1325 free_ftrace_hash(new_hash);
1330 ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash);
1332 ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash);
1335 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1336 struct ftrace_hash **dst, struct ftrace_hash *src)
1338 struct ftrace_func_entry *entry;
1339 struct hlist_node *tn;
1340 struct hlist_head *hhd;
1341 struct ftrace_hash *old_hash;
1342 struct ftrace_hash *new_hash;
1343 int size = src->count;
1349 * Remove the current set, update the hash and add
1352 ftrace_hash_rec_disable(ops, enable);
1355 * If the new source is empty, just free dst and assign it
1359 free_ftrace_hash_rcu(*dst);
1360 rcu_assign_pointer(*dst, EMPTY_HASH);
1361 /* still need to update the function records */
1367 * Make the hash size about 1/2 the # found
1369 for (size /= 2; size; size >>= 1)
1372 /* Don't allocate too much */
1373 if (bits > FTRACE_HASH_MAX_BITS)
1374 bits = FTRACE_HASH_MAX_BITS;
1377 new_hash = alloc_ftrace_hash(bits);
1381 size = 1 << src->size_bits;
1382 for (i = 0; i < size; i++) {
1383 hhd = &src->buckets[i];
1384 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1385 remove_hash_entry(src, entry);
1386 __add_hash_entry(new_hash, entry);
1391 rcu_assign_pointer(*dst, new_hash);
1392 free_ftrace_hash_rcu(old_hash);
1397 * Enable regardless of ret:
1398 * On success, we enable the new hash.
1399 * On failure, we re-enable the original hash.
1401 ftrace_hash_rec_enable(ops, enable);
1407 * Test the hashes for this ops to see if we want to call
1408 * the ops->func or not.
1410 * It's a match if the ip is in the ops->filter_hash or
1411 * the filter_hash does not exist or is empty,
1413 * the ip is not in the ops->notrace_hash.
1415 * This needs to be called with preemption disabled as
1416 * the hashes are freed with call_rcu_sched().
1419 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1421 struct ftrace_hash *filter_hash;
1422 struct ftrace_hash *notrace_hash;
1425 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1427 * There's a small race when adding ops that the ftrace handler
1428 * that wants regs, may be called without them. We can not
1429 * allow that handler to be called if regs is NULL.
1431 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1435 filter_hash = rcu_dereference_raw_notrace(ops->filter_hash);
1436 notrace_hash = rcu_dereference_raw_notrace(ops->notrace_hash);
1438 if ((ftrace_hash_empty(filter_hash) ||
1439 ftrace_lookup_ip(filter_hash, ip)) &&
1440 (ftrace_hash_empty(notrace_hash) ||
1441 !ftrace_lookup_ip(notrace_hash, ip)))
1450 * This is a double for. Do not use 'break' to break out of the loop,
1451 * you must use a goto.
1453 #define do_for_each_ftrace_rec(pg, rec) \
1454 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1456 for (_____i = 0; _____i < pg->index; _____i++) { \
1457 rec = &pg->records[_____i];
1459 #define while_for_each_ftrace_rec() \
1464 static int ftrace_cmp_recs(const void *a, const void *b)
1466 const struct dyn_ftrace *key = a;
1467 const struct dyn_ftrace *rec = b;
1469 if (key->flags < rec->ip)
1471 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1476 static unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1478 struct ftrace_page *pg;
1479 struct dyn_ftrace *rec;
1480 struct dyn_ftrace key;
1483 key.flags = end; /* overload flags, as it is unsigned long */
1485 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1486 if (end < pg->records[0].ip ||
1487 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1489 rec = bsearch(&key, pg->records, pg->index,
1490 sizeof(struct dyn_ftrace),
1500 * ftrace_location - return true if the ip giving is a traced location
1501 * @ip: the instruction pointer to check
1503 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1504 * That is, the instruction that is either a NOP or call to
1505 * the function tracer. It checks the ftrace internal tables to
1506 * determine if the address belongs or not.
1508 unsigned long ftrace_location(unsigned long ip)
1510 return ftrace_location_range(ip, ip);
1514 * ftrace_text_reserved - return true if range contains an ftrace location
1515 * @start: start of range to search
1516 * @end: end of range to search (inclusive). @end points to the last byte to check.
1518 * Returns 1 if @start and @end contains a ftrace location.
1519 * That is, the instruction that is either a NOP or call to
1520 * the function tracer. It checks the ftrace internal tables to
1521 * determine if the address belongs or not.
1523 int ftrace_text_reserved(void *start, void *end)
1527 ret = ftrace_location_range((unsigned long)start,
1528 (unsigned long)end);
1533 static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
1537 struct ftrace_hash *hash;
1538 struct ftrace_hash *other_hash;
1539 struct ftrace_page *pg;
1540 struct dyn_ftrace *rec;
1544 /* Only update if the ops has been registered */
1545 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1549 * In the filter_hash case:
1550 * If the count is zero, we update all records.
1551 * Otherwise we just update the items in the hash.
1553 * In the notrace_hash case:
1554 * We enable the update in the hash.
1555 * As disabling notrace means enabling the tracing,
1556 * and enabling notrace means disabling, the inc variable
1560 hash = ops->filter_hash;
1561 other_hash = ops->notrace_hash;
1562 if (ftrace_hash_empty(hash))
1566 hash = ops->notrace_hash;
1567 other_hash = ops->filter_hash;
1569 * If the notrace hash has no items,
1570 * then there's nothing to do.
1572 if (ftrace_hash_empty(hash))
1576 do_for_each_ftrace_rec(pg, rec) {
1577 int in_other_hash = 0;
1583 * Only the filter_hash affects all records.
1584 * Update if the record is not in the notrace hash.
1586 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1589 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1590 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1595 if (filter_hash && in_hash && !in_other_hash)
1597 else if (!filter_hash && in_hash &&
1598 (in_other_hash || ftrace_hash_empty(other_hash)))
1606 if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX))
1609 * If any ops wants regs saved for this function
1610 * then all ops will get saved regs.
1612 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1613 rec->flags |= FTRACE_FL_REGS;
1615 if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
1620 /* Shortcut, if we handled all records, we are done. */
1621 if (!all && count == hash->count)
1623 } while_for_each_ftrace_rec();
1626 static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
1629 __ftrace_hash_rec_update(ops, filter_hash, 0);
1632 static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
1635 __ftrace_hash_rec_update(ops, filter_hash, 1);
1638 static void print_ip_ins(const char *fmt, unsigned char *p)
1642 printk(KERN_CONT "%s", fmt);
1644 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1645 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1649 * ftrace_bug - report and shutdown function tracer
1650 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1651 * @ip: The address that failed
1653 * The arch code that enables or disables the function tracing
1654 * can call ftrace_bug() when it has detected a problem in
1655 * modifying the code. @failed should be one of either:
1656 * EFAULT - if the problem happens on reading the @ip address
1657 * EINVAL - if what is read at @ip is not what was expected
1658 * EPERM - if the problem happens on writting to the @ip address
1660 void ftrace_bug(int failed, unsigned long ip)
1664 FTRACE_WARN_ON_ONCE(1);
1665 pr_info("ftrace faulted on modifying ");
1669 FTRACE_WARN_ON_ONCE(1);
1670 pr_info("ftrace failed to modify ");
1672 print_ip_ins(" actual: ", (unsigned char *)ip);
1673 printk(KERN_CONT "\n");
1676 FTRACE_WARN_ON_ONCE(1);
1677 pr_info("ftrace faulted on writing ");
1681 FTRACE_WARN_ON_ONCE(1);
1682 pr_info("ftrace faulted on unknown error ");
1687 static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
1689 unsigned long flag = 0UL;
1692 * If we are updating calls:
1694 * If the record has a ref count, then we need to enable it
1695 * because someone is using it.
1697 * Otherwise we make sure its disabled.
1699 * If we are disabling calls, then disable all records that
1702 if (enable && (rec->flags & ~FTRACE_FL_MASK))
1703 flag = FTRACE_FL_ENABLED;
1706 * If enabling and the REGS flag does not match the REGS_EN, then
1707 * do not ignore this record. Set flags to fail the compare against
1711 (!(rec->flags & FTRACE_FL_REGS) != !(rec->flags & FTRACE_FL_REGS_EN)))
1712 flag |= FTRACE_FL_REGS;
1714 /* If the state of this record hasn't changed, then do nothing */
1715 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1716 return FTRACE_UPDATE_IGNORE;
1719 /* Save off if rec is being enabled (for return value) */
1720 flag ^= rec->flags & FTRACE_FL_ENABLED;
1723 rec->flags |= FTRACE_FL_ENABLED;
1724 if (flag & FTRACE_FL_REGS) {
1725 if (rec->flags & FTRACE_FL_REGS)
1726 rec->flags |= FTRACE_FL_REGS_EN;
1728 rec->flags &= ~FTRACE_FL_REGS_EN;
1733 * If this record is being updated from a nop, then
1734 * return UPDATE_MAKE_CALL.
1735 * Otherwise, if the EN flag is set, then return
1736 * UPDATE_MODIFY_CALL_REGS to tell the caller to convert
1737 * from the non-save regs, to a save regs function.
1739 * return UPDATE_MODIFY_CALL to tell the caller to convert
1740 * from the save regs, to a non-save regs function.
1742 if (flag & FTRACE_FL_ENABLED)
1743 return FTRACE_UPDATE_MAKE_CALL;
1744 else if (rec->flags & FTRACE_FL_REGS_EN)
1745 return FTRACE_UPDATE_MODIFY_CALL_REGS;
1747 return FTRACE_UPDATE_MODIFY_CALL;
1751 /* If there's no more users, clear all flags */
1752 if (!(rec->flags & ~FTRACE_FL_MASK))
1755 /* Just disable the record (keep REGS state) */
1756 rec->flags &= ~FTRACE_FL_ENABLED;
1759 return FTRACE_UPDATE_MAKE_NOP;
1763 * ftrace_update_record, set a record that now is tracing or not
1764 * @rec: the record to update
1765 * @enable: set to 1 if the record is tracing, zero to force disable
1767 * The records that represent all functions that can be traced need
1768 * to be updated when tracing has been enabled.
1770 int ftrace_update_record(struct dyn_ftrace *rec, int enable)
1772 return ftrace_check_record(rec, enable, 1);
1776 * ftrace_test_record, check if the record has been enabled or not
1777 * @rec: the record to test
1778 * @enable: set to 1 to check if enabled, 0 if it is disabled
1780 * The arch code may need to test if a record is already set to
1781 * tracing to determine how to modify the function code that it
1784 int ftrace_test_record(struct dyn_ftrace *rec, int enable)
1786 return ftrace_check_record(rec, enable, 0);
1790 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1792 unsigned long ftrace_old_addr;
1793 unsigned long ftrace_addr;
1796 ret = ftrace_update_record(rec, enable);
1798 if (rec->flags & FTRACE_FL_REGS)
1799 ftrace_addr = (unsigned long)FTRACE_REGS_ADDR;
1801 ftrace_addr = (unsigned long)FTRACE_ADDR;
1804 case FTRACE_UPDATE_IGNORE:
1807 case FTRACE_UPDATE_MAKE_CALL:
1808 return ftrace_make_call(rec, ftrace_addr);
1810 case FTRACE_UPDATE_MAKE_NOP:
1811 return ftrace_make_nop(NULL, rec, ftrace_addr);
1813 case FTRACE_UPDATE_MODIFY_CALL_REGS:
1814 case FTRACE_UPDATE_MODIFY_CALL:
1815 if (rec->flags & FTRACE_FL_REGS)
1816 ftrace_old_addr = (unsigned long)FTRACE_ADDR;
1818 ftrace_old_addr = (unsigned long)FTRACE_REGS_ADDR;
1820 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
1823 return -1; /* unknow ftrace bug */
1826 void __weak ftrace_replace_code(int enable)
1828 struct dyn_ftrace *rec;
1829 struct ftrace_page *pg;
1832 if (unlikely(ftrace_disabled))
1835 do_for_each_ftrace_rec(pg, rec) {
1836 failed = __ftrace_replace_code(rec, enable);
1838 ftrace_bug(failed, rec->ip);
1839 /* Stop processing */
1842 } while_for_each_ftrace_rec();
1845 struct ftrace_rec_iter {
1846 struct ftrace_page *pg;
1851 * ftrace_rec_iter_start, start up iterating over traced functions
1853 * Returns an iterator handle that is used to iterate over all
1854 * the records that represent address locations where functions
1857 * May return NULL if no records are available.
1859 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
1862 * We only use a single iterator.
1863 * Protected by the ftrace_lock mutex.
1865 static struct ftrace_rec_iter ftrace_rec_iter;
1866 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
1868 iter->pg = ftrace_pages_start;
1871 /* Could have empty pages */
1872 while (iter->pg && !iter->pg->index)
1873 iter->pg = iter->pg->next;
1882 * ftrace_rec_iter_next, get the next record to process.
1883 * @iter: The handle to the iterator.
1885 * Returns the next iterator after the given iterator @iter.
1887 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
1891 if (iter->index >= iter->pg->index) {
1892 iter->pg = iter->pg->next;
1895 /* Could have empty pages */
1896 while (iter->pg && !iter->pg->index)
1897 iter->pg = iter->pg->next;
1907 * ftrace_rec_iter_record, get the record at the iterator location
1908 * @iter: The current iterator location
1910 * Returns the record that the current @iter is at.
1912 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
1914 return &iter->pg->records[iter->index];
1918 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1925 if (unlikely(ftrace_disabled))
1928 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1930 ftrace_bug(ret, ip);
1937 * archs can override this function if they must do something
1938 * before the modifying code is performed.
1940 int __weak ftrace_arch_code_modify_prepare(void)
1946 * archs can override this function if they must do something
1947 * after the modifying code is performed.
1949 int __weak ftrace_arch_code_modify_post_process(void)
1954 void ftrace_modify_all_code(int command)
1956 if (command & FTRACE_UPDATE_CALLS)
1957 ftrace_replace_code(1);
1958 else if (command & FTRACE_DISABLE_CALLS)
1959 ftrace_replace_code(0);
1961 if (command & FTRACE_UPDATE_TRACE_FUNC)
1962 ftrace_update_ftrace_func(ftrace_trace_function);
1964 if (command & FTRACE_START_FUNC_RET)
1965 ftrace_enable_ftrace_graph_caller();
1966 else if (command & FTRACE_STOP_FUNC_RET)
1967 ftrace_disable_ftrace_graph_caller();
1970 static int __ftrace_modify_code(void *data)
1972 int *command = data;
1974 ftrace_modify_all_code(*command);
1980 * ftrace_run_stop_machine, go back to the stop machine method
1981 * @command: The command to tell ftrace what to do
1983 * If an arch needs to fall back to the stop machine method, the
1984 * it can call this function.
1986 void ftrace_run_stop_machine(int command)
1988 stop_machine(__ftrace_modify_code, &command, NULL);
1992 * arch_ftrace_update_code, modify the code to trace or not trace
1993 * @command: The command that needs to be done
1995 * Archs can override this function if it does not need to
1996 * run stop_machine() to modify code.
1998 void __weak arch_ftrace_update_code(int command)
2000 ftrace_run_stop_machine(command);
2003 static void ftrace_run_update_code(int command)
2007 ret = ftrace_arch_code_modify_prepare();
2008 FTRACE_WARN_ON(ret);
2012 * Do not call function tracer while we update the code.
2013 * We are in stop machine.
2015 function_trace_stop++;
2018 * By default we use stop_machine() to modify the code.
2019 * But archs can do what ever they want as long as it
2020 * is safe. The stop_machine() is the safest, but also
2021 * produces the most overhead.
2023 arch_ftrace_update_code(command);
2025 function_trace_stop--;
2027 ret = ftrace_arch_code_modify_post_process();
2028 FTRACE_WARN_ON(ret);
2031 static ftrace_func_t saved_ftrace_func;
2032 static int ftrace_start_up;
2033 static int global_start_up;
2035 static void ftrace_startup_enable(int command)
2037 if (saved_ftrace_func != ftrace_trace_function) {
2038 saved_ftrace_func = ftrace_trace_function;
2039 command |= FTRACE_UPDATE_TRACE_FUNC;
2042 if (!command || !ftrace_enabled)
2045 ftrace_run_update_code(command);
2048 static int ftrace_startup(struct ftrace_ops *ops, int command)
2050 bool hash_enable = true;
2052 if (unlikely(ftrace_disabled))
2056 command |= FTRACE_UPDATE_CALLS;
2058 /* ops marked global share the filter hashes */
2059 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
2061 /* Don't update hash if global is already set */
2062 if (global_start_up)
2063 hash_enable = false;
2067 ops->flags |= FTRACE_OPS_FL_ENABLED;
2069 ftrace_hash_rec_enable(ops, 1);
2071 ftrace_startup_enable(command);
2076 static void ftrace_shutdown(struct ftrace_ops *ops, int command)
2078 bool hash_disable = true;
2080 if (unlikely(ftrace_disabled))
2085 * Just warn in case of unbalance, no need to kill ftrace, it's not
2086 * critical but the ftrace_call callers may be never nopped again after
2087 * further ftrace uses.
2089 WARN_ON_ONCE(ftrace_start_up < 0);
2091 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
2094 WARN_ON_ONCE(global_start_up < 0);
2095 /* Don't update hash if global still has users */
2096 if (global_start_up) {
2097 WARN_ON_ONCE(!ftrace_start_up);
2098 hash_disable = false;
2103 ftrace_hash_rec_disable(ops, 1);
2105 if (ops != &global_ops || !global_start_up)
2106 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2108 command |= FTRACE_UPDATE_CALLS;
2110 if (saved_ftrace_func != ftrace_trace_function) {
2111 saved_ftrace_func = ftrace_trace_function;
2112 command |= FTRACE_UPDATE_TRACE_FUNC;
2115 if (!command || !ftrace_enabled)
2118 ftrace_run_update_code(command);
2121 static void ftrace_startup_sysctl(void)
2123 if (unlikely(ftrace_disabled))
2126 /* Force update next time */
2127 saved_ftrace_func = NULL;
2128 /* ftrace_start_up is true if we want ftrace running */
2129 if (ftrace_start_up)
2130 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
2133 static void ftrace_shutdown_sysctl(void)
2135 if (unlikely(ftrace_disabled))
2138 /* ftrace_start_up is true if ftrace is running */
2139 if (ftrace_start_up)
2140 ftrace_run_update_code(FTRACE_DISABLE_CALLS);
2143 static cycle_t ftrace_update_time;
2144 static unsigned long ftrace_update_cnt;
2145 unsigned long ftrace_update_tot_cnt;
2147 static inline int ops_traces_mod(struct ftrace_ops *ops)
2150 * Filter_hash being empty will default to trace module.
2151 * But notrace hash requires a test of individual module functions.
2153 return ftrace_hash_empty(ops->filter_hash) &&
2154 ftrace_hash_empty(ops->notrace_hash);
2158 * Check if the current ops references the record.
2160 * If the ops traces all functions, then it was already accounted for.
2161 * If the ops does not trace the current record function, skip it.
2162 * If the ops ignores the function via notrace filter, skip it.
2165 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2167 /* If ops isn't enabled, ignore it */
2168 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2171 /* If ops traces all mods, we already accounted for it */
2172 if (ops_traces_mod(ops))
2175 /* The function must be in the filter */
2176 if (!ftrace_hash_empty(ops->filter_hash) &&
2177 !ftrace_lookup_ip(ops->filter_hash, rec->ip))
2180 /* If in notrace hash, we ignore it too */
2181 if (ftrace_lookup_ip(ops->notrace_hash, rec->ip))
2187 static int referenced_filters(struct dyn_ftrace *rec)
2189 struct ftrace_ops *ops;
2192 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
2193 if (ops_references_rec(ops, rec))
2200 static int ftrace_update_code(struct module *mod)
2202 struct ftrace_page *pg;
2203 struct dyn_ftrace *p;
2204 cycle_t start, stop;
2205 unsigned long ref = 0;
2210 * When adding a module, we need to check if tracers are
2211 * currently enabled and if they are set to trace all functions.
2212 * If they are, we need to enable the module functions as well
2213 * as update the reference counts for those function records.
2216 struct ftrace_ops *ops;
2218 for (ops = ftrace_ops_list;
2219 ops != &ftrace_list_end; ops = ops->next) {
2220 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
2221 if (ops_traces_mod(ops))
2229 start = ftrace_now(raw_smp_processor_id());
2230 ftrace_update_cnt = 0;
2232 for (pg = ftrace_new_pgs; pg; pg = pg->next) {
2234 for (i = 0; i < pg->index; i++) {
2237 /* If something went wrong, bail without enabling anything */
2238 if (unlikely(ftrace_disabled))
2241 p = &pg->records[i];
2243 cnt += referenced_filters(p);
2247 * Do the initial record conversion from mcount jump
2248 * to the NOP instructions.
2250 if (!ftrace_code_disable(mod, p))
2253 ftrace_update_cnt++;
2256 * If the tracing is enabled, go ahead and enable the record.
2258 * The reason not to enable the record immediatelly is the
2259 * inherent check of ftrace_make_nop/ftrace_make_call for
2260 * correct previous instructions. Making first the NOP
2261 * conversion puts the module to the correct state, thus
2262 * passing the ftrace_make_call check.
2264 if (ftrace_start_up && cnt) {
2265 int failed = __ftrace_replace_code(p, 1);
2267 ftrace_bug(failed, p->ip);
2272 ftrace_new_pgs = NULL;
2274 stop = ftrace_now(raw_smp_processor_id());
2275 ftrace_update_time = stop - start;
2276 ftrace_update_tot_cnt += ftrace_update_cnt;
2281 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2286 if (WARN_ON(!count))
2289 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2292 * We want to fill as much as possible. No more than a page
2295 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2299 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2302 /* if we can't allocate this size, try something smaller */
2309 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2318 static struct ftrace_page *
2319 ftrace_allocate_pages(unsigned long num_to_init)
2321 struct ftrace_page *start_pg;
2322 struct ftrace_page *pg;
2329 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
2334 * Try to allocate as much as possible in one continues
2335 * location that fills in all of the space. We want to
2336 * waste as little space as possible.
2339 cnt = ftrace_allocate_records(pg, num_to_init);
2347 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
2358 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
2359 free_pages((unsigned long)pg->records, order);
2360 start_pg = pg->next;
2364 pr_info("ftrace: FAILED to allocate memory for functions\n");
2368 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
2373 pr_info("ftrace: No functions to be traced?\n");
2377 cnt = num_to_init / ENTRIES_PER_PAGE;
2378 pr_info("ftrace: allocating %ld entries in %d pages\n",
2379 num_to_init, cnt + 1);
2384 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
2386 struct ftrace_iterator {
2389 struct ftrace_page *pg;
2390 struct dyn_ftrace *func;
2391 struct ftrace_func_probe *probe;
2392 struct trace_parser parser;
2393 struct ftrace_hash *hash;
2394 struct ftrace_ops *ops;
2401 t_hash_next(struct seq_file *m, loff_t *pos)
2403 struct ftrace_iterator *iter = m->private;
2404 struct hlist_node *hnd = NULL;
2405 struct hlist_head *hhd;
2411 hnd = &iter->probe->node;
2413 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
2416 hhd = &ftrace_func_hash[iter->hidx];
2418 if (hlist_empty(hhd)) {
2434 if (WARN_ON_ONCE(!hnd))
2437 iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
2442 static void *t_hash_start(struct seq_file *m, loff_t *pos)
2444 struct ftrace_iterator *iter = m->private;
2448 if (!(iter->flags & FTRACE_ITER_DO_HASH))
2451 if (iter->func_pos > *pos)
2455 for (l = 0; l <= (*pos - iter->func_pos); ) {
2456 p = t_hash_next(m, &l);
2463 /* Only set this if we have an item */
2464 iter->flags |= FTRACE_ITER_HASH;
2470 t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
2472 struct ftrace_func_probe *rec;
2475 if (WARN_ON_ONCE(!rec))
2478 if (rec->ops->print)
2479 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
2481 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
2484 seq_printf(m, ":%p", rec->data);
2491 t_next(struct seq_file *m, void *v, loff_t *pos)
2493 struct ftrace_iterator *iter = m->private;
2494 struct ftrace_ops *ops = iter->ops;
2495 struct dyn_ftrace *rec = NULL;
2497 if (unlikely(ftrace_disabled))
2500 if (iter->flags & FTRACE_ITER_HASH)
2501 return t_hash_next(m, pos);
2504 iter->pos = iter->func_pos = *pos;
2506 if (iter->flags & FTRACE_ITER_PRINTALL)
2507 return t_hash_start(m, pos);
2510 if (iter->idx >= iter->pg->index) {
2511 if (iter->pg->next) {
2512 iter->pg = iter->pg->next;
2517 rec = &iter->pg->records[iter->idx++];
2518 if (((iter->flags & FTRACE_ITER_FILTER) &&
2519 !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||
2521 ((iter->flags & FTRACE_ITER_NOTRACE) &&
2522 !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
2524 ((iter->flags & FTRACE_ITER_ENABLED) &&
2525 !(rec->flags & FTRACE_FL_ENABLED))) {
2533 return t_hash_start(m, pos);
2540 static void reset_iter_read(struct ftrace_iterator *iter)
2544 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_HASH);
2547 static void *t_start(struct seq_file *m, loff_t *pos)
2549 struct ftrace_iterator *iter = m->private;
2550 struct ftrace_ops *ops = iter->ops;
2554 mutex_lock(&ftrace_lock);
2556 if (unlikely(ftrace_disabled))
2560 * If an lseek was done, then reset and start from beginning.
2562 if (*pos < iter->pos)
2563 reset_iter_read(iter);
2566 * For set_ftrace_filter reading, if we have the filter
2567 * off, we can short cut and just print out that all
2568 * functions are enabled.
2570 if (iter->flags & FTRACE_ITER_FILTER &&
2571 ftrace_hash_empty(ops->filter_hash)) {
2573 return t_hash_start(m, pos);
2574 iter->flags |= FTRACE_ITER_PRINTALL;
2575 /* reset in case of seek/pread */
2576 iter->flags &= ~FTRACE_ITER_HASH;
2580 if (iter->flags & FTRACE_ITER_HASH)
2581 return t_hash_start(m, pos);
2584 * Unfortunately, we need to restart at ftrace_pages_start
2585 * every time we let go of the ftrace_mutex. This is because
2586 * those pointers can change without the lock.
2588 iter->pg = ftrace_pages_start;
2590 for (l = 0; l <= *pos; ) {
2591 p = t_next(m, p, &l);
2597 return t_hash_start(m, pos);
2602 static void t_stop(struct seq_file *m, void *p)
2604 mutex_unlock(&ftrace_lock);
2607 static int t_show(struct seq_file *m, void *v)
2609 struct ftrace_iterator *iter = m->private;
2610 struct dyn_ftrace *rec;
2612 if (iter->flags & FTRACE_ITER_HASH)
2613 return t_hash_show(m, iter);
2615 if (iter->flags & FTRACE_ITER_PRINTALL) {
2616 seq_printf(m, "#### all functions enabled ####\n");
2625 seq_printf(m, "%ps", (void *)rec->ip);
2626 if (iter->flags & FTRACE_ITER_ENABLED)
2627 seq_printf(m, " (%ld)%s",
2628 rec->flags & ~FTRACE_FL_MASK,
2629 rec->flags & FTRACE_FL_REGS ? " R" : "");
2630 seq_printf(m, "\n");
2635 static const struct seq_operations show_ftrace_seq_ops = {
2643 ftrace_avail_open(struct inode *inode, struct file *file)
2645 struct ftrace_iterator *iter;
2647 if (unlikely(ftrace_disabled))
2650 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
2652 iter->pg = ftrace_pages_start;
2653 iter->ops = &global_ops;
2656 return iter ? 0 : -ENOMEM;
2660 ftrace_enabled_open(struct inode *inode, struct file *file)
2662 struct ftrace_iterator *iter;
2664 if (unlikely(ftrace_disabled))
2667 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
2669 iter->pg = ftrace_pages_start;
2670 iter->flags = FTRACE_ITER_ENABLED;
2671 iter->ops = &global_ops;
2674 return iter ? 0 : -ENOMEM;
2677 static void ftrace_filter_reset(struct ftrace_hash *hash)
2679 mutex_lock(&ftrace_lock);
2680 ftrace_hash_clear(hash);
2681 mutex_unlock(&ftrace_lock);
2685 * ftrace_regex_open - initialize function tracer filter files
2686 * @ops: The ftrace_ops that hold the hash filters
2687 * @flag: The type of filter to process
2688 * @inode: The inode, usually passed in to your open routine
2689 * @file: The file, usually passed in to your open routine
2691 * ftrace_regex_open() initializes the filter files for the
2692 * @ops. Depending on @flag it may process the filter hash or
2693 * the notrace hash of @ops. With this called from the open
2694 * routine, you can use ftrace_filter_write() for the write
2695 * routine if @flag has FTRACE_ITER_FILTER set, or
2696 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
2697 * ftrace_filter_lseek() should be used as the lseek routine, and
2698 * release must call ftrace_regex_release().
2701 ftrace_regex_open(struct ftrace_ops *ops, int flag,
2702 struct inode *inode, struct file *file)
2704 struct ftrace_iterator *iter;
2705 struct ftrace_hash *hash;
2708 ftrace_ops_init(ops);
2710 if (unlikely(ftrace_disabled))
2713 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2717 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
2725 mutex_lock(&ops->regex_lock);
2727 if (flag & FTRACE_ITER_NOTRACE)
2728 hash = ops->notrace_hash;
2730 hash = ops->filter_hash;
2732 if (file->f_mode & FMODE_WRITE) {
2733 iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
2735 trace_parser_put(&iter->parser);
2742 if ((file->f_mode & FMODE_WRITE) &&
2743 (file->f_flags & O_TRUNC))
2744 ftrace_filter_reset(iter->hash);
2746 if (file->f_mode & FMODE_READ) {
2747 iter->pg = ftrace_pages_start;
2749 ret = seq_open(file, &show_ftrace_seq_ops);
2751 struct seq_file *m = file->private_data;
2755 free_ftrace_hash(iter->hash);
2756 trace_parser_put(&iter->parser);
2760 file->private_data = iter;
2763 mutex_unlock(&ops->regex_lock);
2769 ftrace_filter_open(struct inode *inode, struct file *file)
2771 return ftrace_regex_open(&global_ops,
2772 FTRACE_ITER_FILTER | FTRACE_ITER_DO_HASH,
2777 ftrace_notrace_open(struct inode *inode, struct file *file)
2779 return ftrace_regex_open(&global_ops, FTRACE_ITER_NOTRACE,
2783 static int ftrace_match(char *str, char *regex, int len, int type)
2790 if (strcmp(str, regex) == 0)
2793 case MATCH_FRONT_ONLY:
2794 if (strncmp(str, regex, len) == 0)
2797 case MATCH_MIDDLE_ONLY:
2798 if (strstr(str, regex))
2801 case MATCH_END_ONLY:
2803 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
2812 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
2814 struct ftrace_func_entry *entry;
2817 entry = ftrace_lookup_ip(hash, rec->ip);
2819 /* Do nothing if it doesn't exist */
2823 free_hash_entry(hash, entry);
2825 /* Do nothing if it exists */
2829 ret = add_hash_entry(hash, rec->ip);
2835 ftrace_match_record(struct dyn_ftrace *rec, char *mod,
2836 char *regex, int len, int type)
2838 char str[KSYM_SYMBOL_LEN];
2841 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
2844 /* module lookup requires matching the module */
2845 if (!modname || strcmp(modname, mod))
2848 /* blank search means to match all funcs in the mod */
2853 return ftrace_match(str, regex, len, type);
2857 match_records(struct ftrace_hash *hash, char *buff,
2858 int len, char *mod, int not)
2860 unsigned search_len = 0;
2861 struct ftrace_page *pg;
2862 struct dyn_ftrace *rec;
2863 int type = MATCH_FULL;
2864 char *search = buff;
2869 type = filter_parse_regex(buff, len, &search, ¬);
2870 search_len = strlen(search);
2873 mutex_lock(&ftrace_lock);
2875 if (unlikely(ftrace_disabled))
2878 do_for_each_ftrace_rec(pg, rec) {
2879 if (ftrace_match_record(rec, mod, search, search_len, type)) {
2880 ret = enter_record(hash, rec, not);
2887 } while_for_each_ftrace_rec();
2889 mutex_unlock(&ftrace_lock);
2895 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
2897 return match_records(hash, buff, len, NULL, 0);
2901 ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
2905 /* blank or '*' mean the same */
2906 if (strcmp(buff, "*") == 0)
2909 /* handle the case of 'dont filter this module' */
2910 if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
2915 return match_records(hash, buff, strlen(buff), mod, not);
2919 * We register the module command as a template to show others how
2920 * to register the a command as well.
2924 ftrace_mod_callback(struct ftrace_hash *hash,
2925 char *func, char *cmd, char *param, int enable)
2931 * cmd == 'mod' because we only registered this func
2932 * for the 'mod' ftrace_func_command.
2933 * But if you register one func with multiple commands,
2934 * you can tell which command was used by the cmd
2938 /* we must have a module name */
2942 mod = strsep(¶m, ":");
2946 ret = ftrace_match_module_records(hash, func, mod);
2955 static struct ftrace_func_command ftrace_mod_cmd = {
2957 .func = ftrace_mod_callback,
2960 static int __init ftrace_mod_cmd_init(void)
2962 return register_ftrace_command(&ftrace_mod_cmd);
2964 core_initcall(ftrace_mod_cmd_init);
2966 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
2967 struct ftrace_ops *op, struct pt_regs *pt_regs)
2969 struct ftrace_func_probe *entry;
2970 struct hlist_head *hhd;
2973 key = hash_long(ip, FTRACE_HASH_BITS);
2975 hhd = &ftrace_func_hash[key];
2977 if (hlist_empty(hhd))
2981 * Disable preemption for these calls to prevent a RCU grace
2982 * period. This syncs the hash iteration and freeing of items
2983 * on the hash. rcu_read_lock is too dangerous here.
2985 preempt_disable_notrace();
2986 hlist_for_each_entry_rcu_notrace(entry, hhd, node) {
2987 if (entry->ip == ip)
2988 entry->ops->func(ip, parent_ip, &entry->data);
2990 preempt_enable_notrace();
2993 static struct ftrace_ops trace_probe_ops __read_mostly =
2995 .func = function_trace_probe_call,
2996 .flags = FTRACE_OPS_FL_INITIALIZED,
2997 INIT_REGEX_LOCK(trace_probe_ops)
3000 static int ftrace_probe_registered;
3002 static void __enable_ftrace_function_probe(void)
3007 if (ftrace_probe_registered) {
3008 /* still need to update the function call sites */
3010 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3014 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3015 struct hlist_head *hhd = &ftrace_func_hash[i];
3019 /* Nothing registered? */
3020 if (i == FTRACE_FUNC_HASHSIZE)
3023 ret = __register_ftrace_function(&trace_probe_ops);
3025 ret = ftrace_startup(&trace_probe_ops, 0);
3027 ftrace_probe_registered = 1;
3030 static void __disable_ftrace_function_probe(void)
3035 if (!ftrace_probe_registered)
3038 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3039 struct hlist_head *hhd = &ftrace_func_hash[i];
3044 /* no more funcs left */
3045 ret = __unregister_ftrace_function(&trace_probe_ops);
3047 ftrace_shutdown(&trace_probe_ops, 0);
3049 ftrace_probe_registered = 0;
3053 static void ftrace_free_entry(struct ftrace_func_probe *entry)
3055 if (entry->ops->free)
3056 entry->ops->free(entry->ops, entry->ip, &entry->data);
3061 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3064 struct ftrace_func_probe *entry;
3065 struct ftrace_hash **orig_hash = &trace_probe_ops.filter_hash;
3066 struct ftrace_hash *hash;
3067 struct ftrace_page *pg;
3068 struct dyn_ftrace *rec;
3075 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
3076 len = strlen(search);
3078 /* we do not support '!' for function probes */
3082 mutex_lock(&trace_probe_ops.regex_lock);
3084 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3090 if (unlikely(ftrace_disabled)) {
3095 mutex_lock(&ftrace_lock);
3097 do_for_each_ftrace_rec(pg, rec) {
3099 if (!ftrace_match_record(rec, NULL, search, len, type))
3102 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
3104 /* If we did not process any, then return error */
3115 * The caller might want to do something special
3116 * for each function we find. We call the callback
3117 * to give the caller an opportunity to do so.
3120 if (ops->init(ops, rec->ip, &entry->data) < 0) {
3121 /* caller does not like this func */
3127 ret = enter_record(hash, rec, 0);
3135 entry->ip = rec->ip;
3137 key = hash_long(entry->ip, FTRACE_HASH_BITS);
3138 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
3140 } while_for_each_ftrace_rec();
3142 ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3146 __enable_ftrace_function_probe();
3149 mutex_unlock(&ftrace_lock);
3151 mutex_unlock(&trace_probe_ops.regex_lock);
3152 free_ftrace_hash(hash);
3158 PROBE_TEST_FUNC = 1,
3163 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3164 void *data, int flags)
3166 struct ftrace_func_entry *rec_entry;
3167 struct ftrace_func_probe *entry;
3168 struct ftrace_func_probe *p;
3169 struct ftrace_hash **orig_hash = &trace_probe_ops.filter_hash;
3170 struct list_head free_list;
3171 struct ftrace_hash *hash;
3172 struct hlist_node *tmp;
3173 char str[KSYM_SYMBOL_LEN];
3174 int type = MATCH_FULL;
3178 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
3183 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
3184 len = strlen(search);
3186 /* we do not support '!' for function probes */
3191 mutex_lock(&trace_probe_ops.regex_lock);
3193 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3195 /* Hmm, should report this somehow */
3198 INIT_LIST_HEAD(&free_list);
3200 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3201 struct hlist_head *hhd = &ftrace_func_hash[i];
3203 hlist_for_each_entry_safe(entry, tmp, hhd, node) {
3205 /* break up if statements for readability */
3206 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
3209 if ((flags & PROBE_TEST_DATA) && entry->data != data)
3212 /* do this last, since it is the most expensive */
3214 kallsyms_lookup(entry->ip, NULL, NULL,
3216 if (!ftrace_match(str, glob, len, type))
3220 rec_entry = ftrace_lookup_ip(hash, entry->ip);
3221 /* It is possible more than one entry had this ip */
3223 free_hash_entry(hash, rec_entry);
3225 hlist_del_rcu(&entry->node);
3226 list_add(&entry->free_list, &free_list);
3229 mutex_lock(&ftrace_lock);
3230 __disable_ftrace_function_probe();
3232 * Remove after the disable is called. Otherwise, if the last
3233 * probe is removed, a null hash means *all enabled*.
3235 ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3236 synchronize_sched();
3237 list_for_each_entry_safe(entry, p, &free_list, free_list) {
3238 list_del(&entry->free_list);
3239 ftrace_free_entry(entry);
3241 mutex_unlock(&ftrace_lock);
3244 mutex_unlock(&trace_probe_ops.regex_lock);
3245 free_ftrace_hash(hash);
3249 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3252 __unregister_ftrace_function_probe(glob, ops, data,
3253 PROBE_TEST_FUNC | PROBE_TEST_DATA);
3257 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
3259 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
3262 void unregister_ftrace_function_probe_all(char *glob)
3264 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
3267 static LIST_HEAD(ftrace_commands);
3268 static DEFINE_MUTEX(ftrace_cmd_mutex);
3270 int register_ftrace_command(struct ftrace_func_command *cmd)
3272 struct ftrace_func_command *p;
3275 mutex_lock(&ftrace_cmd_mutex);
3276 list_for_each_entry(p, &ftrace_commands, list) {
3277 if (strcmp(cmd->name, p->name) == 0) {
3282 list_add(&cmd->list, &ftrace_commands);
3284 mutex_unlock(&ftrace_cmd_mutex);
3289 int unregister_ftrace_command(struct ftrace_func_command *cmd)
3291 struct ftrace_func_command *p, *n;
3294 mutex_lock(&ftrace_cmd_mutex);
3295 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
3296 if (strcmp(cmd->name, p->name) == 0) {
3298 list_del_init(&p->list);
3303 mutex_unlock(&ftrace_cmd_mutex);
3308 static int ftrace_process_regex(struct ftrace_hash *hash,
3309 char *buff, int len, int enable)
3311 char *func, *command, *next = buff;
3312 struct ftrace_func_command *p;
3315 func = strsep(&next, ":");
3318 ret = ftrace_match_records(hash, func, len);
3328 command = strsep(&next, ":");
3330 mutex_lock(&ftrace_cmd_mutex);
3331 list_for_each_entry(p, &ftrace_commands, list) {
3332 if (strcmp(p->name, command) == 0) {
3333 ret = p->func(hash, func, command, next, enable);
3338 mutex_unlock(&ftrace_cmd_mutex);
3344 ftrace_regex_write(struct file *file, const char __user *ubuf,
3345 size_t cnt, loff_t *ppos, int enable)
3347 struct ftrace_iterator *iter;
3348 struct trace_parser *parser;
3354 if (file->f_mode & FMODE_READ) {
3355 struct seq_file *m = file->private_data;
3358 iter = file->private_data;
3360 if (unlikely(ftrace_disabled))
3363 /* iter->hash is a local copy, so we don't need regex_lock */
3365 parser = &iter->parser;
3366 read = trace_get_user(parser, ubuf, cnt, ppos);
3368 if (read >= 0 && trace_parser_loaded(parser) &&
3369 !trace_parser_cont(parser)) {
3370 ret = ftrace_process_regex(iter->hash, parser->buffer,
3371 parser->idx, enable);
3372 trace_parser_clear(parser);
3383 ftrace_filter_write(struct file *file, const char __user *ubuf,
3384 size_t cnt, loff_t *ppos)
3386 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
3390 ftrace_notrace_write(struct file *file, const char __user *ubuf,
3391 size_t cnt, loff_t *ppos)
3393 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
3397 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
3399 struct ftrace_func_entry *entry;
3401 if (!ftrace_location(ip))
3405 entry = ftrace_lookup_ip(hash, ip);
3408 free_hash_entry(hash, entry);
3412 return add_hash_entry(hash, ip);
3416 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
3417 unsigned long ip, int remove, int reset, int enable)
3419 struct ftrace_hash **orig_hash;
3420 struct ftrace_hash *hash;
3423 /* All global ops uses the global ops filters */
3424 if (ops->flags & FTRACE_OPS_FL_GLOBAL)
3427 if (unlikely(ftrace_disabled))
3430 mutex_lock(&ops->regex_lock);
3433 orig_hash = &ops->filter_hash;
3435 orig_hash = &ops->notrace_hash;
3437 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3440 goto out_regex_unlock;
3444 ftrace_filter_reset(hash);
3445 if (buf && !ftrace_match_records(hash, buf, len)) {
3447 goto out_regex_unlock;
3450 ret = ftrace_match_addr(hash, ip, remove);
3452 goto out_regex_unlock;
3455 mutex_lock(&ftrace_lock);
3456 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3457 if (!ret && ops->flags & FTRACE_OPS_FL_ENABLED
3459 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3461 mutex_unlock(&ftrace_lock);
3464 mutex_unlock(&ops->regex_lock);
3466 free_ftrace_hash(hash);
3471 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
3472 int reset, int enable)
3474 return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
3478 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
3479 * @ops - the ops to set the filter with
3480 * @ip - the address to add to or remove from the filter.
3481 * @remove - non zero to remove the ip from the filter
3482 * @reset - non zero to reset all filters before applying this filter.
3484 * Filters denote which functions should be enabled when tracing is enabled
3485 * If @ip is NULL, it failes to update filter.
3487 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
3488 int remove, int reset)
3490 ftrace_ops_init(ops);
3491 return ftrace_set_addr(ops, ip, remove, reset, 1);
3493 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
3496 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
3497 int reset, int enable)
3499 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
3503 * ftrace_set_filter - set a function to filter on in ftrace
3504 * @ops - the ops to set the filter with
3505 * @buf - the string that holds the function filter text.
3506 * @len - the length of the string.
3507 * @reset - non zero to reset all filters before applying this filter.
3509 * Filters denote which functions should be enabled when tracing is enabled.
3510 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3512 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
3515 ftrace_ops_init(ops);
3516 return ftrace_set_regex(ops, buf, len, reset, 1);
3518 EXPORT_SYMBOL_GPL(ftrace_set_filter);
3521 * ftrace_set_notrace - set a function to not trace in ftrace
3522 * @ops - the ops to set the notrace filter with
3523 * @buf - the string that holds the function notrace text.
3524 * @len - the length of the string.
3525 * @reset - non zero to reset all filters before applying this filter.
3527 * Notrace Filters denote which functions should not be enabled when tracing
3528 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3531 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
3534 ftrace_ops_init(ops);
3535 return ftrace_set_regex(ops, buf, len, reset, 0);
3537 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
3539 * ftrace_set_filter - set a function to filter on in ftrace
3540 * @ops - the ops to set the filter with
3541 * @buf - the string that holds the function filter text.
3542 * @len - the length of the string.
3543 * @reset - non zero to reset all filters before applying this filter.
3545 * Filters denote which functions should be enabled when tracing is enabled.
3546 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3548 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
3550 ftrace_set_regex(&global_ops, buf, len, reset, 1);
3552 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
3555 * ftrace_set_notrace - set a function to not trace in ftrace
3556 * @ops - the ops to set the notrace filter with
3557 * @buf - the string that holds the function notrace text.
3558 * @len - the length of the string.
3559 * @reset - non zero to reset all filters before applying this filter.
3561 * Notrace Filters denote which functions should not be enabled when tracing
3562 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3565 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
3567 ftrace_set_regex(&global_ops, buf, len, reset, 0);
3569 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
3572 * command line interface to allow users to set filters on boot up.
3574 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
3575 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
3576 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
3578 static int __init set_ftrace_notrace(char *str)
3580 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
3583 __setup("ftrace_notrace=", set_ftrace_notrace);
3585 static int __init set_ftrace_filter(char *str)
3587 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
3590 __setup("ftrace_filter=", set_ftrace_filter);
3592 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3593 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
3594 static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
3596 static int __init set_graph_function(char *str)
3598 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
3601 __setup("ftrace_graph_filter=", set_graph_function);
3603 static void __init set_ftrace_early_graph(char *buf)
3609 func = strsep(&buf, ",");
3610 /* we allow only one expression at a time */
3611 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3614 printk(KERN_DEBUG "ftrace: function %s not "
3615 "traceable\n", func);
3618 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3621 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
3625 ftrace_ops_init(ops);
3628 func = strsep(&buf, ",");
3629 ftrace_set_regex(ops, func, strlen(func), 0, enable);
3633 static void __init set_ftrace_early_filters(void)
3635 if (ftrace_filter_buf[0])
3636 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
3637 if (ftrace_notrace_buf[0])
3638 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
3639 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3640 if (ftrace_graph_buf[0])
3641 set_ftrace_early_graph(ftrace_graph_buf);
3642 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3645 int ftrace_regex_release(struct inode *inode, struct file *file)
3647 struct seq_file *m = (struct seq_file *)file->private_data;
3648 struct ftrace_iterator *iter;
3649 struct ftrace_hash **orig_hash;
3650 struct trace_parser *parser;
3654 if (file->f_mode & FMODE_READ) {
3656 seq_release(inode, file);
3658 iter = file->private_data;
3660 parser = &iter->parser;
3661 if (trace_parser_loaded(parser)) {
3662 parser->buffer[parser->idx] = 0;
3663 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
3666 trace_parser_put(parser);
3668 mutex_lock(&iter->ops->regex_lock);
3670 if (file->f_mode & FMODE_WRITE) {
3671 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
3674 orig_hash = &iter->ops->filter_hash;
3676 orig_hash = &iter->ops->notrace_hash;
3678 mutex_lock(&ftrace_lock);
3679 ret = ftrace_hash_move(iter->ops, filter_hash,
3680 orig_hash, iter->hash);
3681 if (!ret && (iter->ops->flags & FTRACE_OPS_FL_ENABLED)
3683 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3685 mutex_unlock(&ftrace_lock);
3688 mutex_unlock(&iter->ops->regex_lock);
3689 free_ftrace_hash(iter->hash);
3695 static const struct file_operations ftrace_avail_fops = {
3696 .open = ftrace_avail_open,
3698 .llseek = seq_lseek,
3699 .release = seq_release_private,
3702 static const struct file_operations ftrace_enabled_fops = {
3703 .open = ftrace_enabled_open,
3705 .llseek = seq_lseek,
3706 .release = seq_release_private,
3709 static const struct file_operations ftrace_filter_fops = {
3710 .open = ftrace_filter_open,
3712 .write = ftrace_filter_write,
3713 .llseek = ftrace_filter_lseek,
3714 .release = ftrace_regex_release,
3717 static const struct file_operations ftrace_notrace_fops = {
3718 .open = ftrace_notrace_open,
3720 .write = ftrace_notrace_write,
3721 .llseek = ftrace_filter_lseek,
3722 .release = ftrace_regex_release,
3725 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3727 static DEFINE_MUTEX(graph_lock);
3729 int ftrace_graph_count;
3730 int ftrace_graph_filter_enabled;
3731 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
3734 __g_next(struct seq_file *m, loff_t *pos)
3736 if (*pos >= ftrace_graph_count)
3738 return &ftrace_graph_funcs[*pos];
3742 g_next(struct seq_file *m, void *v, loff_t *pos)
3745 return __g_next(m, pos);
3748 static void *g_start(struct seq_file *m, loff_t *pos)
3750 mutex_lock(&graph_lock);
3752 /* Nothing, tell g_show to print all functions are enabled */
3753 if (!ftrace_graph_filter_enabled && !*pos)
3756 return __g_next(m, pos);
3759 static void g_stop(struct seq_file *m, void *p)
3761 mutex_unlock(&graph_lock);
3764 static int g_show(struct seq_file *m, void *v)
3766 unsigned long *ptr = v;
3771 if (ptr == (unsigned long *)1) {
3772 seq_printf(m, "#### all functions enabled ####\n");
3776 seq_printf(m, "%ps\n", (void *)*ptr);
3781 static const struct seq_operations ftrace_graph_seq_ops = {
3789 ftrace_graph_open(struct inode *inode, struct file *file)
3793 if (unlikely(ftrace_disabled))
3796 mutex_lock(&graph_lock);
3797 if ((file->f_mode & FMODE_WRITE) &&
3798 (file->f_flags & O_TRUNC)) {
3799 ftrace_graph_filter_enabled = 0;
3800 ftrace_graph_count = 0;
3801 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
3803 mutex_unlock(&graph_lock);
3805 if (file->f_mode & FMODE_READ)
3806 ret = seq_open(file, &ftrace_graph_seq_ops);
3812 ftrace_graph_release(struct inode *inode, struct file *file)
3814 if (file->f_mode & FMODE_READ)
3815 seq_release(inode, file);
3820 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
3822 struct dyn_ftrace *rec;
3823 struct ftrace_page *pg;
3832 type = filter_parse_regex(buffer, strlen(buffer), &search, ¬);
3833 if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
3836 search_len = strlen(search);
3838 mutex_lock(&ftrace_lock);
3840 if (unlikely(ftrace_disabled)) {
3841 mutex_unlock(&ftrace_lock);
3845 do_for_each_ftrace_rec(pg, rec) {
3847 if (ftrace_match_record(rec, NULL, search, search_len, type)) {
3848 /* if it is in the array */
3850 for (i = 0; i < *idx; i++) {
3851 if (array[i] == rec->ip) {
3860 array[(*idx)++] = rec->ip;
3861 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
3866 array[i] = array[--(*idx)];
3872 } while_for_each_ftrace_rec();
3874 mutex_unlock(&ftrace_lock);
3879 ftrace_graph_filter_enabled = !!(*idx);
3885 ftrace_graph_write(struct file *file, const char __user *ubuf,
3886 size_t cnt, loff_t *ppos)
3888 struct trace_parser parser;
3894 mutex_lock(&graph_lock);
3896 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
3901 read = trace_get_user(&parser, ubuf, cnt, ppos);
3903 if (read >= 0 && trace_parser_loaded((&parser))) {
3904 parser.buffer[parser.idx] = 0;
3906 /* we allow only one expression at a time */
3907 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3916 trace_parser_put(&parser);
3918 mutex_unlock(&graph_lock);
3923 static const struct file_operations ftrace_graph_fops = {
3924 .open = ftrace_graph_open,
3926 .write = ftrace_graph_write,
3927 .llseek = ftrace_filter_lseek,
3928 .release = ftrace_graph_release,
3930 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3932 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
3935 trace_create_file("available_filter_functions", 0444,
3936 d_tracer, NULL, &ftrace_avail_fops);
3938 trace_create_file("enabled_functions", 0444,
3939 d_tracer, NULL, &ftrace_enabled_fops);
3941 trace_create_file("set_ftrace_filter", 0644, d_tracer,
3942 NULL, &ftrace_filter_fops);
3944 trace_create_file("set_ftrace_notrace", 0644, d_tracer,
3945 NULL, &ftrace_notrace_fops);
3947 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3948 trace_create_file("set_graph_function", 0444, d_tracer,
3950 &ftrace_graph_fops);
3951 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3956 static int ftrace_cmp_ips(const void *a, const void *b)
3958 const unsigned long *ipa = a;
3959 const unsigned long *ipb = b;
3968 static void ftrace_swap_ips(void *a, void *b, int size)
3970 unsigned long *ipa = a;
3971 unsigned long *ipb = b;
3979 static int ftrace_process_locs(struct module *mod,
3980 unsigned long *start,
3983 struct ftrace_page *start_pg;
3984 struct ftrace_page *pg;
3985 struct dyn_ftrace *rec;
3986 unsigned long count;
3989 unsigned long flags = 0; /* Shut up gcc */
3992 count = end - start;
3997 sort(start, count, sizeof(*start),
3998 ftrace_cmp_ips, ftrace_swap_ips);
4000 start_pg = ftrace_allocate_pages(count);
4004 mutex_lock(&ftrace_lock);
4007 * Core and each module needs their own pages, as
4008 * modules will free them when they are removed.
4009 * Force a new page to be allocated for modules.
4012 WARN_ON(ftrace_pages || ftrace_pages_start);
4013 /* First initialization */
4014 ftrace_pages = ftrace_pages_start = start_pg;
4019 if (WARN_ON(ftrace_pages->next)) {
4020 /* Hmm, we have free pages? */
4021 while (ftrace_pages->next)
4022 ftrace_pages = ftrace_pages->next;
4025 ftrace_pages->next = start_pg;
4031 addr = ftrace_call_adjust(*p++);
4033 * Some architecture linkers will pad between
4034 * the different mcount_loc sections of different
4035 * object files to satisfy alignments.
4036 * Skip any NULL pointers.
4041 if (pg->index == pg->size) {
4042 /* We should have allocated enough */
4043 if (WARN_ON(!pg->next))
4048 rec = &pg->records[pg->index++];
4052 /* We should have used all pages */
4055 /* Assign the last page to ftrace_pages */
4058 /* These new locations need to be initialized */
4059 ftrace_new_pgs = start_pg;
4062 * We only need to disable interrupts on start up
4063 * because we are modifying code that an interrupt
4064 * may execute, and the modification is not atomic.
4065 * But for modules, nothing runs the code we modify
4066 * until we are finished with it, and there's no
4067 * reason to cause large interrupt latencies while we do it.
4070 local_irq_save(flags);
4071 ftrace_update_code(mod);
4073 local_irq_restore(flags);
4076 mutex_unlock(&ftrace_lock);
4081 #ifdef CONFIG_MODULES
4083 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
4085 void ftrace_release_mod(struct module *mod)
4087 struct dyn_ftrace *rec;
4088 struct ftrace_page **last_pg;
4089 struct ftrace_page *pg;
4092 mutex_lock(&ftrace_lock);
4094 if (ftrace_disabled)
4098 * Each module has its own ftrace_pages, remove
4099 * them from the list.
4101 last_pg = &ftrace_pages_start;
4102 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
4103 rec = &pg->records[0];
4104 if (within_module_core(rec->ip, mod)) {
4106 * As core pages are first, the first
4107 * page should never be a module page.
4109 if (WARN_ON(pg == ftrace_pages_start))
4112 /* Check if we are deleting the last page */
4113 if (pg == ftrace_pages)
4114 ftrace_pages = next_to_ftrace_page(last_pg);
4116 *last_pg = pg->next;
4117 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
4118 free_pages((unsigned long)pg->records, order);
4121 last_pg = &pg->next;
4124 mutex_unlock(&ftrace_lock);
4127 static void ftrace_init_module(struct module *mod,
4128 unsigned long *start, unsigned long *end)
4130 if (ftrace_disabled || start == end)
4132 ftrace_process_locs(mod, start, end);
4135 static int ftrace_module_notify_enter(struct notifier_block *self,
4136 unsigned long val, void *data)
4138 struct module *mod = data;
4140 if (val == MODULE_STATE_COMING)
4141 ftrace_init_module(mod, mod->ftrace_callsites,
4142 mod->ftrace_callsites +
4143 mod->num_ftrace_callsites);
4147 static int ftrace_module_notify_exit(struct notifier_block *self,
4148 unsigned long val, void *data)
4150 struct module *mod = data;
4152 if (val == MODULE_STATE_GOING)
4153 ftrace_release_mod(mod);
4158 static int ftrace_module_notify_enter(struct notifier_block *self,
4159 unsigned long val, void *data)
4163 static int ftrace_module_notify_exit(struct notifier_block *self,
4164 unsigned long val, void *data)
4168 #endif /* CONFIG_MODULES */
4170 struct notifier_block ftrace_module_enter_nb = {
4171 .notifier_call = ftrace_module_notify_enter,
4172 .priority = INT_MAX, /* Run before anything that can use kprobes */
4175 struct notifier_block ftrace_module_exit_nb = {
4176 .notifier_call = ftrace_module_notify_exit,
4177 .priority = INT_MIN, /* Run after anything that can remove kprobes */
4180 extern unsigned long __start_mcount_loc[];
4181 extern unsigned long __stop_mcount_loc[];
4183 void __init ftrace_init(void)
4185 unsigned long count, addr, flags;
4188 /* Keep the ftrace pointer to the stub */
4189 addr = (unsigned long)ftrace_stub;
4191 local_irq_save(flags);
4192 ftrace_dyn_arch_init(&addr);
4193 local_irq_restore(flags);
4195 /* ftrace_dyn_arch_init places the return code in addr */
4199 count = __stop_mcount_loc - __start_mcount_loc;
4201 ret = ftrace_dyn_table_alloc(count);
4205 last_ftrace_enabled = ftrace_enabled = 1;
4207 ret = ftrace_process_locs(NULL,
4211 ret = register_module_notifier(&ftrace_module_enter_nb);
4213 pr_warning("Failed to register trace ftrace module enter notifier\n");
4215 ret = register_module_notifier(&ftrace_module_exit_nb);
4217 pr_warning("Failed to register trace ftrace module exit notifier\n");
4219 set_ftrace_early_filters();
4223 ftrace_disabled = 1;
4228 static struct ftrace_ops global_ops = {
4229 .func = ftrace_stub,
4230 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
4231 INIT_REGEX_LOCK(global_ops)
4234 static int __init ftrace_nodyn_init(void)
4239 core_initcall(ftrace_nodyn_init);
4241 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
4242 static inline void ftrace_startup_enable(int command) { }
4243 /* Keep as macros so we do not need to define the commands */
4244 # define ftrace_startup(ops, command) \
4246 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
4249 # define ftrace_shutdown(ops, command) do { } while (0)
4250 # define ftrace_startup_sysctl() do { } while (0)
4251 # define ftrace_shutdown_sysctl() do { } while (0)
4254 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
4259 #endif /* CONFIG_DYNAMIC_FTRACE */
4262 ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
4263 struct ftrace_ops *op, struct pt_regs *regs)
4265 if (unlikely(trace_recursion_test(TRACE_CONTROL_BIT)))
4269 * Some of the ops may be dynamically allocated,
4270 * they must be freed after a synchronize_sched().
4272 preempt_disable_notrace();
4273 trace_recursion_set(TRACE_CONTROL_BIT);
4274 do_for_each_ftrace_op(op, ftrace_control_list) {
4275 if (!(op->flags & FTRACE_OPS_FL_STUB) &&
4276 !ftrace_function_local_disabled(op) &&
4277 ftrace_ops_test(op, ip, regs))
4278 op->func(ip, parent_ip, op, regs);
4279 } while_for_each_ftrace_op(op);
4280 trace_recursion_clear(TRACE_CONTROL_BIT);
4281 preempt_enable_notrace();
4284 static struct ftrace_ops control_ops = {
4285 .func = ftrace_ops_control_func,
4286 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
4287 INIT_REGEX_LOCK(control_ops)
4291 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
4292 struct ftrace_ops *ignored, struct pt_regs *regs)
4294 struct ftrace_ops *op;
4297 if (function_trace_stop)
4300 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
4305 * Some of the ops may be dynamically allocated,
4306 * they must be freed after a synchronize_sched().
4308 preempt_disable_notrace();
4309 do_for_each_ftrace_op(op, ftrace_ops_list) {
4310 if (ftrace_ops_test(op, ip, regs))
4311 op->func(ip, parent_ip, op, regs);
4312 } while_for_each_ftrace_op(op);
4313 preempt_enable_notrace();
4314 trace_clear_recursion(bit);
4318 * Some archs only support passing ip and parent_ip. Even though
4319 * the list function ignores the op parameter, we do not want any
4320 * C side effects, where a function is called without the caller
4321 * sending a third parameter.
4322 * Archs are to support both the regs and ftrace_ops at the same time.
4323 * If they support ftrace_ops, it is assumed they support regs.
4324 * If call backs want to use regs, they must either check for regs
4325 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
4326 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
4327 * An architecture can pass partial regs with ftrace_ops and still
4328 * set the ARCH_SUPPORT_FTARCE_OPS.
4330 #if ARCH_SUPPORTS_FTRACE_OPS
4331 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
4332 struct ftrace_ops *op, struct pt_regs *regs)
4334 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
4337 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
4339 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
4343 static void clear_ftrace_swapper(void)
4345 struct task_struct *p;
4349 for_each_online_cpu(cpu) {
4351 clear_tsk_trace_trace(p);
4356 static void set_ftrace_swapper(void)
4358 struct task_struct *p;
4362 for_each_online_cpu(cpu) {
4364 set_tsk_trace_trace(p);
4369 static void clear_ftrace_pid(struct pid *pid)
4371 struct task_struct *p;
4374 do_each_pid_task(pid, PIDTYPE_PID, p) {
4375 clear_tsk_trace_trace(p);
4376 } while_each_pid_task(pid, PIDTYPE_PID, p);
4382 static void set_ftrace_pid(struct pid *pid)
4384 struct task_struct *p;
4387 do_each_pid_task(pid, PIDTYPE_PID, p) {
4388 set_tsk_trace_trace(p);
4389 } while_each_pid_task(pid, PIDTYPE_PID, p);
4393 static void clear_ftrace_pid_task(struct pid *pid)
4395 if (pid == ftrace_swapper_pid)
4396 clear_ftrace_swapper();
4398 clear_ftrace_pid(pid);
4401 static void set_ftrace_pid_task(struct pid *pid)
4403 if (pid == ftrace_swapper_pid)
4404 set_ftrace_swapper();
4406 set_ftrace_pid(pid);
4409 static int ftrace_pid_add(int p)
4412 struct ftrace_pid *fpid;
4415 mutex_lock(&ftrace_lock);
4418 pid = ftrace_swapper_pid;
4420 pid = find_get_pid(p);
4427 list_for_each_entry(fpid, &ftrace_pids, list)
4428 if (fpid->pid == pid)
4433 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
4437 list_add(&fpid->list, &ftrace_pids);
4440 set_ftrace_pid_task(pid);
4442 ftrace_update_pid_func();
4443 ftrace_startup_enable(0);
4445 mutex_unlock(&ftrace_lock);
4449 if (pid != ftrace_swapper_pid)
4453 mutex_unlock(&ftrace_lock);
4457 static void ftrace_pid_reset(void)
4459 struct ftrace_pid *fpid, *safe;
4461 mutex_lock(&ftrace_lock);
4462 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
4463 struct pid *pid = fpid->pid;
4465 clear_ftrace_pid_task(pid);
4467 list_del(&fpid->list);
4471 ftrace_update_pid_func();
4472 ftrace_startup_enable(0);
4474 mutex_unlock(&ftrace_lock);
4477 static void *fpid_start(struct seq_file *m, loff_t *pos)
4479 mutex_lock(&ftrace_lock);
4481 if (list_empty(&ftrace_pids) && (!*pos))
4484 return seq_list_start(&ftrace_pids, *pos);
4487 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
4492 return seq_list_next(v, &ftrace_pids, pos);
4495 static void fpid_stop(struct seq_file *m, void *p)
4497 mutex_unlock(&ftrace_lock);
4500 static int fpid_show(struct seq_file *m, void *v)
4502 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
4504 if (v == (void *)1) {
4505 seq_printf(m, "no pid\n");
4509 if (fpid->pid == ftrace_swapper_pid)
4510 seq_printf(m, "swapper tasks\n");
4512 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
4517 static const struct seq_operations ftrace_pid_sops = {
4518 .start = fpid_start,
4525 ftrace_pid_open(struct inode *inode, struct file *file)
4529 if ((file->f_mode & FMODE_WRITE) &&
4530 (file->f_flags & O_TRUNC))
4533 if (file->f_mode & FMODE_READ)
4534 ret = seq_open(file, &ftrace_pid_sops);
4540 ftrace_pid_write(struct file *filp, const char __user *ubuf,
4541 size_t cnt, loff_t *ppos)
4547 if (cnt >= sizeof(buf))
4550 if (copy_from_user(&buf, ubuf, cnt))
4556 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
4557 * to clean the filter quietly.
4559 tmp = strstrip(buf);
4560 if (strlen(tmp) == 0)
4563 ret = kstrtol(tmp, 10, &val);
4567 ret = ftrace_pid_add(val);
4569 return ret ? ret : cnt;
4573 ftrace_pid_release(struct inode *inode, struct file *file)
4575 if (file->f_mode & FMODE_READ)
4576 seq_release(inode, file);
4581 static const struct file_operations ftrace_pid_fops = {
4582 .open = ftrace_pid_open,
4583 .write = ftrace_pid_write,
4585 .llseek = ftrace_filter_lseek,
4586 .release = ftrace_pid_release,
4589 static __init int ftrace_init_debugfs(void)
4591 struct dentry *d_tracer;
4593 d_tracer = tracing_init_dentry();
4597 ftrace_init_dyn_debugfs(d_tracer);
4599 trace_create_file("set_ftrace_pid", 0644, d_tracer,
4600 NULL, &ftrace_pid_fops);
4602 ftrace_profile_debugfs(d_tracer);
4606 fs_initcall(ftrace_init_debugfs);
4609 * ftrace_kill - kill ftrace
4611 * This function should be used by panic code. It stops ftrace
4612 * but in a not so nice way. If you need to simply kill ftrace
4613 * from a non-atomic section, use ftrace_kill.
4615 void ftrace_kill(void)
4617 ftrace_disabled = 1;
4619 clear_ftrace_function();
4623 * Test if ftrace is dead or not.
4625 int ftrace_is_dead(void)
4627 return ftrace_disabled;
4631 * register_ftrace_function - register a function for profiling
4632 * @ops - ops structure that holds the function for profiling.
4634 * Register a function to be called by all functions in the
4637 * Note: @ops->func and all the functions it calls must be labeled
4638 * with "notrace", otherwise it will go into a
4641 int register_ftrace_function(struct ftrace_ops *ops)
4645 ftrace_ops_init(ops);
4647 mutex_lock(&ftrace_lock);
4649 ret = __register_ftrace_function(ops);
4651 ret = ftrace_startup(ops, 0);
4653 mutex_unlock(&ftrace_lock);
4657 EXPORT_SYMBOL_GPL(register_ftrace_function);
4660 * unregister_ftrace_function - unregister a function for profiling.
4661 * @ops - ops structure that holds the function to unregister
4663 * Unregister a function that was added to be called by ftrace profiling.
4665 int unregister_ftrace_function(struct ftrace_ops *ops)
4669 mutex_lock(&ftrace_lock);
4670 ret = __unregister_ftrace_function(ops);
4672 ftrace_shutdown(ops, 0);
4673 mutex_unlock(&ftrace_lock);
4677 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
4680 ftrace_enable_sysctl(struct ctl_table *table, int write,
4681 void __user *buffer, size_t *lenp,
4686 mutex_lock(&ftrace_lock);
4688 if (unlikely(ftrace_disabled))
4691 ret = proc_dointvec(table, write, buffer, lenp, ppos);
4693 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
4696 last_ftrace_enabled = !!ftrace_enabled;
4698 if (ftrace_enabled) {
4700 ftrace_startup_sysctl();
4702 /* we are starting ftrace again */
4703 if (ftrace_ops_list != &ftrace_list_end)
4704 update_ftrace_function();
4707 /* stopping ftrace calls (just send to ftrace_stub) */
4708 ftrace_trace_function = ftrace_stub;
4710 ftrace_shutdown_sysctl();
4714 mutex_unlock(&ftrace_lock);
4718 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4720 static int ftrace_graph_active;
4721 static struct notifier_block ftrace_suspend_notifier;
4723 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
4728 /* The callbacks that hook a function */
4729 trace_func_graph_ret_t ftrace_graph_return =
4730 (trace_func_graph_ret_t)ftrace_stub;
4731 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
4733 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
4734 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
4738 unsigned long flags;
4739 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
4740 struct task_struct *g, *t;
4742 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
4743 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
4744 * sizeof(struct ftrace_ret_stack),
4746 if (!ret_stack_list[i]) {
4754 read_lock_irqsave(&tasklist_lock, flags);
4755 do_each_thread(g, t) {
4761 if (t->ret_stack == NULL) {
4762 atomic_set(&t->tracing_graph_pause, 0);
4763 atomic_set(&t->trace_overrun, 0);
4764 t->curr_ret_stack = -1;
4765 /* Make sure the tasks see the -1 first: */
4767 t->ret_stack = ret_stack_list[start++];
4769 } while_each_thread(g, t);
4772 read_unlock_irqrestore(&tasklist_lock, flags);
4774 for (i = start; i < end; i++)
4775 kfree(ret_stack_list[i]);
4780 ftrace_graph_probe_sched_switch(void *ignore,
4781 struct task_struct *prev, struct task_struct *next)
4783 unsigned long long timestamp;
4787 * Does the user want to count the time a function was asleep.
4788 * If so, do not update the time stamps.
4790 if (trace_flags & TRACE_ITER_SLEEP_TIME)
4793 timestamp = trace_clock_local();
4795 prev->ftrace_timestamp = timestamp;
4797 /* only process tasks that we timestamped */
4798 if (!next->ftrace_timestamp)
4802 * Update all the counters in next to make up for the
4803 * time next was sleeping.
4805 timestamp -= next->ftrace_timestamp;
4807 for (index = next->curr_ret_stack; index >= 0; index--)
4808 next->ret_stack[index].calltime += timestamp;
4811 /* Allocate a return stack for each task */
4812 static int start_graph_tracing(void)
4814 struct ftrace_ret_stack **ret_stack_list;
4817 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
4818 sizeof(struct ftrace_ret_stack *),
4821 if (!ret_stack_list)
4824 /* The cpu_boot init_task->ret_stack will never be freed */
4825 for_each_online_cpu(cpu) {
4826 if (!idle_task(cpu)->ret_stack)
4827 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
4831 ret = alloc_retstack_tasklist(ret_stack_list);
4832 } while (ret == -EAGAIN);
4835 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4837 pr_info("ftrace_graph: Couldn't activate tracepoint"
4838 " probe to kernel_sched_switch\n");
4841 kfree(ret_stack_list);
4846 * Hibernation protection.
4847 * The state of the current task is too much unstable during
4848 * suspend/restore to disk. We want to protect against that.
4851 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
4855 case PM_HIBERNATION_PREPARE:
4856 pause_graph_tracing();
4859 case PM_POST_HIBERNATION:
4860 unpause_graph_tracing();
4866 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
4867 trace_func_graph_ent_t entryfunc)
4871 mutex_lock(&ftrace_lock);
4873 /* we currently allow only one tracer registered at a time */
4874 if (ftrace_graph_active) {
4879 ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
4880 register_pm_notifier(&ftrace_suspend_notifier);
4882 ftrace_graph_active++;
4883 ret = start_graph_tracing();
4885 ftrace_graph_active--;
4889 ftrace_graph_return = retfunc;
4890 ftrace_graph_entry = entryfunc;
4892 ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET);
4895 mutex_unlock(&ftrace_lock);
4899 void unregister_ftrace_graph(void)
4901 mutex_lock(&ftrace_lock);
4903 if (unlikely(!ftrace_graph_active))
4906 ftrace_graph_active--;
4907 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
4908 ftrace_graph_entry = ftrace_graph_entry_stub;
4909 ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET);
4910 unregister_pm_notifier(&ftrace_suspend_notifier);
4911 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4914 mutex_unlock(&ftrace_lock);
4917 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
4920 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
4922 atomic_set(&t->tracing_graph_pause, 0);
4923 atomic_set(&t->trace_overrun, 0);
4924 t->ftrace_timestamp = 0;
4925 /* make curr_ret_stack visible before we add the ret_stack */
4927 t->ret_stack = ret_stack;
4931 * Allocate a return stack for the idle task. May be the first
4932 * time through, or it may be done by CPU hotplug online.
4934 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
4936 t->curr_ret_stack = -1;
4938 * The idle task has no parent, it either has its own
4939 * stack or no stack at all.
4942 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
4944 if (ftrace_graph_active) {
4945 struct ftrace_ret_stack *ret_stack;
4947 ret_stack = per_cpu(idle_ret_stack, cpu);
4949 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4950 * sizeof(struct ftrace_ret_stack),
4954 per_cpu(idle_ret_stack, cpu) = ret_stack;
4956 graph_init_task(t, ret_stack);
4960 /* Allocate a return stack for newly created task */
4961 void ftrace_graph_init_task(struct task_struct *t)
4963 /* Make sure we do not use the parent ret_stack */
4964 t->ret_stack = NULL;
4965 t->curr_ret_stack = -1;
4967 if (ftrace_graph_active) {
4968 struct ftrace_ret_stack *ret_stack;
4970 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4971 * sizeof(struct ftrace_ret_stack),
4975 graph_init_task(t, ret_stack);
4979 void ftrace_graph_exit_task(struct task_struct *t)
4981 struct ftrace_ret_stack *ret_stack = t->ret_stack;
4983 t->ret_stack = NULL;
4984 /* NULL must become visible to IRQs before we free it: */
4990 void ftrace_graph_stop(void)