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_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;
88 /* What to set function_trace_op to */
89 static struct ftrace_ops *set_function_trace_op;
91 /* List for set_ftrace_pid's pids. */
92 LIST_HEAD(ftrace_pids);
94 struct list_head list;
99 * ftrace_disabled is set when an anomaly is discovered.
100 * ftrace_disabled is much stronger than ftrace_enabled.
102 static int ftrace_disabled __read_mostly;
104 static DEFINE_MUTEX(ftrace_lock);
106 static struct ftrace_ops *ftrace_control_list __read_mostly = &ftrace_list_end;
107 static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
108 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
109 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
110 static struct ftrace_ops global_ops;
111 static struct ftrace_ops control_ops;
113 #if ARCH_SUPPORTS_FTRACE_OPS
114 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
115 struct ftrace_ops *op, struct pt_regs *regs);
117 /* See comment below, where ftrace_ops_list_func is defined */
118 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
119 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
123 * Traverse the ftrace_global_list, invoking all entries. The reason that we
124 * can use rcu_dereference_raw_notrace() is that elements removed from this list
125 * are simply leaked, so there is no need to interact with a grace-period
126 * mechanism. The rcu_dereference_raw_notrace() calls are needed to handle
127 * concurrent insertions into the ftrace_global_list.
129 * Silly Alpha and silly pointer-speculation compiler optimizations!
131 #define do_for_each_ftrace_op(op, list) \
132 op = rcu_dereference_raw_notrace(list); \
136 * Optimized for just a single item in the list (as that is the normal case).
138 #define while_for_each_ftrace_op(op) \
139 while (likely(op = rcu_dereference_raw_notrace((op)->next)) && \
140 unlikely((op) != &ftrace_list_end))
142 static inline void ftrace_ops_init(struct ftrace_ops *ops)
144 #ifdef CONFIG_DYNAMIC_FTRACE
145 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
146 mutex_init(&ops->regex_lock);
147 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
153 * ftrace_nr_registered_ops - return number of ops registered
155 * Returns the number of ftrace_ops registered and tracing functions
157 int ftrace_nr_registered_ops(void)
159 struct ftrace_ops *ops;
162 mutex_lock(&ftrace_lock);
164 for (ops = ftrace_ops_list;
165 ops != &ftrace_list_end; ops = ops->next)
168 mutex_unlock(&ftrace_lock);
173 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
174 struct ftrace_ops *op, struct pt_regs *regs)
176 if (!test_tsk_trace_trace(current))
179 ftrace_pid_function(ip, parent_ip, op, regs);
182 static void set_ftrace_pid_function(ftrace_func_t func)
184 /* do not set ftrace_pid_function to itself! */
185 if (func != ftrace_pid_func)
186 ftrace_pid_function = func;
190 * clear_ftrace_function - reset the ftrace function
192 * This NULLs the ftrace function and in essence stops
193 * tracing. There may be lag
195 void clear_ftrace_function(void)
197 ftrace_trace_function = ftrace_stub;
198 ftrace_pid_function = ftrace_stub;
201 static void control_ops_disable_all(struct ftrace_ops *ops)
205 for_each_possible_cpu(cpu)
206 *per_cpu_ptr(ops->disabled, cpu) = 1;
209 static int control_ops_alloc(struct ftrace_ops *ops)
211 int __percpu *disabled;
213 disabled = alloc_percpu(int);
217 ops->disabled = disabled;
218 control_ops_disable_all(ops);
222 static void ftrace_sync(struct work_struct *work)
225 * This function is just a stub to implement a hard force
226 * of synchronize_sched(). This requires synchronizing
227 * tasks even in userspace and idle.
229 * Yes, function tracing is rude.
233 static void ftrace_sync_ipi(void *data)
235 /* Probably not needed, but do it anyway */
239 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
240 static void update_function_graph_func(void);
242 static inline void update_function_graph_func(void) { }
245 static void update_ftrace_function(void)
250 * If we are at the end of the list and this ops is
251 * recursion safe and not dynamic and the arch supports passing ops,
252 * then have the mcount trampoline call the function directly.
254 if (ftrace_ops_list == &ftrace_list_end ||
255 (ftrace_ops_list->next == &ftrace_list_end &&
256 !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC) &&
257 (ftrace_ops_list->flags & FTRACE_OPS_FL_RECURSION_SAFE) &&
258 !FTRACE_FORCE_LIST_FUNC)) {
259 /* Set the ftrace_ops that the arch callback uses */
260 set_function_trace_op = ftrace_ops_list;
261 func = ftrace_ops_list->func;
263 /* Just use the default ftrace_ops */
264 set_function_trace_op = &ftrace_list_end;
265 func = ftrace_ops_list_func;
268 /* If there's no change, then do nothing more here */
269 if (ftrace_trace_function == func)
272 update_function_graph_func();
275 * If we are using the list function, it doesn't care
276 * about the function_trace_ops.
278 if (func == ftrace_ops_list_func) {
279 ftrace_trace_function = func;
281 * Don't even bother setting function_trace_ops,
282 * it would be racy to do so anyway.
287 #ifndef CONFIG_DYNAMIC_FTRACE
289 * For static tracing, we need to be a bit more careful.
290 * The function change takes affect immediately. Thus,
291 * we need to coorditate the setting of the function_trace_ops
292 * with the setting of the ftrace_trace_function.
294 * Set the function to the list ops, which will call the
295 * function we want, albeit indirectly, but it handles the
296 * ftrace_ops and doesn't depend on function_trace_op.
298 ftrace_trace_function = ftrace_ops_list_func;
300 * Make sure all CPUs see this. Yes this is slow, but static
301 * tracing is slow and nasty to have enabled.
303 schedule_on_each_cpu(ftrace_sync);
304 /* Now all cpus are using the list ops. */
305 function_trace_op = set_function_trace_op;
306 /* Make sure the function_trace_op is visible on all CPUs */
308 /* Nasty way to force a rmb on all cpus */
309 smp_call_function(ftrace_sync_ipi, NULL, 1);
310 /* OK, we are all set to update the ftrace_trace_function now! */
311 #endif /* !CONFIG_DYNAMIC_FTRACE */
313 ftrace_trace_function = func;
316 static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
320 * We are entering ops into the list but another
321 * CPU might be walking that list. We need to make sure
322 * the ops->next pointer is valid before another CPU sees
323 * the ops pointer included into the list.
325 rcu_assign_pointer(*list, ops);
328 static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
330 struct ftrace_ops **p;
333 * If we are removing the last function, then simply point
334 * to the ftrace_stub.
336 if (*list == ops && ops->next == &ftrace_list_end) {
337 *list = &ftrace_list_end;
341 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
352 static void add_ftrace_list_ops(struct ftrace_ops **list,
353 struct ftrace_ops *main_ops,
354 struct ftrace_ops *ops)
356 int first = *list == &ftrace_list_end;
357 add_ftrace_ops(list, ops);
359 add_ftrace_ops(&ftrace_ops_list, main_ops);
362 static int remove_ftrace_list_ops(struct ftrace_ops **list,
363 struct ftrace_ops *main_ops,
364 struct ftrace_ops *ops)
366 int ret = remove_ftrace_ops(list, ops);
367 if (!ret && *list == &ftrace_list_end)
368 ret = remove_ftrace_ops(&ftrace_ops_list, main_ops);
372 static int __register_ftrace_function(struct ftrace_ops *ops)
374 if (ops->flags & FTRACE_OPS_FL_DELETED)
377 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
380 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
382 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
383 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
384 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
386 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
387 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
390 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
391 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
394 if (!core_kernel_data((unsigned long)ops))
395 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
397 if (ops->flags & FTRACE_OPS_FL_CONTROL) {
398 if (control_ops_alloc(ops))
400 add_ftrace_list_ops(&ftrace_control_list, &control_ops, ops);
402 add_ftrace_ops(&ftrace_ops_list, ops);
405 update_ftrace_function();
410 static int __unregister_ftrace_function(struct ftrace_ops *ops)
414 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
417 if (ops->flags & FTRACE_OPS_FL_CONTROL) {
418 ret = remove_ftrace_list_ops(&ftrace_control_list,
421 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
427 update_ftrace_function();
432 static void ftrace_update_pid_func(void)
434 /* Only do something if we are tracing something */
435 if (ftrace_trace_function == ftrace_stub)
438 update_ftrace_function();
441 #ifdef CONFIG_FUNCTION_PROFILER
442 struct ftrace_profile {
443 struct hlist_node node;
445 unsigned long counter;
446 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
447 unsigned long long time;
448 unsigned long long time_squared;
452 struct ftrace_profile_page {
453 struct ftrace_profile_page *next;
455 struct ftrace_profile records[];
458 struct ftrace_profile_stat {
460 struct hlist_head *hash;
461 struct ftrace_profile_page *pages;
462 struct ftrace_profile_page *start;
463 struct tracer_stat stat;
466 #define PROFILE_RECORDS_SIZE \
467 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
469 #define PROFILES_PER_PAGE \
470 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
472 static int ftrace_profile_enabled __read_mostly;
474 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
475 static DEFINE_MUTEX(ftrace_profile_lock);
477 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
479 #define FTRACE_PROFILE_HASH_BITS 10
480 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
483 function_stat_next(void *v, int idx)
485 struct ftrace_profile *rec = v;
486 struct ftrace_profile_page *pg;
488 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
494 if ((void *)rec >= (void *)&pg->records[pg->index]) {
498 rec = &pg->records[0];
506 static void *function_stat_start(struct tracer_stat *trace)
508 struct ftrace_profile_stat *stat =
509 container_of(trace, struct ftrace_profile_stat, stat);
511 if (!stat || !stat->start)
514 return function_stat_next(&stat->start->records[0], 0);
517 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
518 /* function graph compares on total time */
519 static int function_stat_cmp(void *p1, void *p2)
521 struct ftrace_profile *a = p1;
522 struct ftrace_profile *b = p2;
524 if (a->time < b->time)
526 if (a->time > b->time)
532 /* not function graph compares against hits */
533 static int function_stat_cmp(void *p1, void *p2)
535 struct ftrace_profile *a = p1;
536 struct ftrace_profile *b = p2;
538 if (a->counter < b->counter)
540 if (a->counter > b->counter)
547 static int function_stat_headers(struct seq_file *m)
549 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
550 seq_printf(m, " Function "
553 "--- ---- --- ---\n");
555 seq_printf(m, " Function Hit\n"
561 static int function_stat_show(struct seq_file *m, void *v)
563 struct ftrace_profile *rec = v;
564 char str[KSYM_SYMBOL_LEN];
566 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
567 static struct trace_seq s;
568 unsigned long long avg;
569 unsigned long long stddev;
571 mutex_lock(&ftrace_profile_lock);
573 /* we raced with function_profile_reset() */
574 if (unlikely(rec->counter == 0)) {
579 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
580 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
582 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
585 do_div(avg, rec->counter);
587 /* Sample standard deviation (s^2) */
588 if (rec->counter <= 1)
592 * Apply Welford's method:
593 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
595 stddev = rec->counter * rec->time_squared -
596 rec->time * rec->time;
599 * Divide only 1000 for ns^2 -> us^2 conversion.
600 * trace_print_graph_duration will divide 1000 again.
602 do_div(stddev, rec->counter * (rec->counter - 1) * 1000);
606 trace_print_graph_duration(rec->time, &s);
607 trace_seq_puts(&s, " ");
608 trace_print_graph_duration(avg, &s);
609 trace_seq_puts(&s, " ");
610 trace_print_graph_duration(stddev, &s);
611 trace_print_seq(m, &s);
615 mutex_unlock(&ftrace_profile_lock);
620 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
622 struct ftrace_profile_page *pg;
624 pg = stat->pages = stat->start;
627 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
632 memset(stat->hash, 0,
633 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
636 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
638 struct ftrace_profile_page *pg;
643 /* If we already allocated, do nothing */
647 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
651 #ifdef CONFIG_DYNAMIC_FTRACE
652 functions = ftrace_update_tot_cnt;
655 * We do not know the number of functions that exist because
656 * dynamic tracing is what counts them. With past experience
657 * we have around 20K functions. That should be more than enough.
658 * It is highly unlikely we will execute every function in
664 pg = stat->start = stat->pages;
666 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
668 for (i = 1; i < pages; i++) {
669 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
680 unsigned long tmp = (unsigned long)pg;
692 static int ftrace_profile_init_cpu(int cpu)
694 struct ftrace_profile_stat *stat;
697 stat = &per_cpu(ftrace_profile_stats, cpu);
700 /* If the profile is already created, simply reset it */
701 ftrace_profile_reset(stat);
706 * We are profiling all functions, but usually only a few thousand
707 * functions are hit. We'll make a hash of 1024 items.
709 size = FTRACE_PROFILE_HASH_SIZE;
711 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
716 /* Preallocate the function profiling pages */
717 if (ftrace_profile_pages_init(stat) < 0) {
726 static int ftrace_profile_init(void)
731 for_each_possible_cpu(cpu) {
732 ret = ftrace_profile_init_cpu(cpu);
740 /* interrupts must be disabled */
741 static struct ftrace_profile *
742 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
744 struct ftrace_profile *rec;
745 struct hlist_head *hhd;
748 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
749 hhd = &stat->hash[key];
751 if (hlist_empty(hhd))
754 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
762 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
763 struct ftrace_profile *rec)
767 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
768 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
772 * The memory is already allocated, this simply finds a new record to use.
774 static struct ftrace_profile *
775 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
777 struct ftrace_profile *rec = NULL;
779 /* prevent recursion (from NMIs) */
780 if (atomic_inc_return(&stat->disabled) != 1)
784 * Try to find the function again since an NMI
785 * could have added it
787 rec = ftrace_find_profiled_func(stat, ip);
791 if (stat->pages->index == PROFILES_PER_PAGE) {
792 if (!stat->pages->next)
794 stat->pages = stat->pages->next;
797 rec = &stat->pages->records[stat->pages->index++];
799 ftrace_add_profile(stat, rec);
802 atomic_dec(&stat->disabled);
808 function_profile_call(unsigned long ip, unsigned long parent_ip,
809 struct ftrace_ops *ops, struct pt_regs *regs)
811 struct ftrace_profile_stat *stat;
812 struct ftrace_profile *rec;
815 if (!ftrace_profile_enabled)
818 local_irq_save(flags);
820 stat = &__get_cpu_var(ftrace_profile_stats);
821 if (!stat->hash || !ftrace_profile_enabled)
824 rec = ftrace_find_profiled_func(stat, ip);
826 rec = ftrace_profile_alloc(stat, ip);
833 local_irq_restore(flags);
836 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
837 static int profile_graph_entry(struct ftrace_graph_ent *trace)
839 function_profile_call(trace->func, 0, NULL, NULL);
843 static void profile_graph_return(struct ftrace_graph_ret *trace)
845 struct ftrace_profile_stat *stat;
846 unsigned long long calltime;
847 struct ftrace_profile *rec;
850 local_irq_save(flags);
851 stat = &__get_cpu_var(ftrace_profile_stats);
852 if (!stat->hash || !ftrace_profile_enabled)
855 /* If the calltime was zero'd ignore it */
856 if (!trace->calltime)
859 calltime = trace->rettime - trace->calltime;
861 if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
864 index = trace->depth;
866 /* Append this call time to the parent time to subtract */
868 current->ret_stack[index - 1].subtime += calltime;
870 if (current->ret_stack[index].subtime < calltime)
871 calltime -= current->ret_stack[index].subtime;
876 rec = ftrace_find_profiled_func(stat, trace->func);
878 rec->time += calltime;
879 rec->time_squared += calltime * calltime;
883 local_irq_restore(flags);
886 static int register_ftrace_profiler(void)
888 return register_ftrace_graph(&profile_graph_return,
889 &profile_graph_entry);
892 static void unregister_ftrace_profiler(void)
894 unregister_ftrace_graph();
897 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
898 .func = function_profile_call,
899 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
900 INIT_REGEX_LOCK(ftrace_profile_ops)
903 static int register_ftrace_profiler(void)
905 return register_ftrace_function(&ftrace_profile_ops);
908 static void unregister_ftrace_profiler(void)
910 unregister_ftrace_function(&ftrace_profile_ops);
912 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
915 ftrace_profile_write(struct file *filp, const char __user *ubuf,
916 size_t cnt, loff_t *ppos)
921 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
927 mutex_lock(&ftrace_profile_lock);
928 if (ftrace_profile_enabled ^ val) {
930 ret = ftrace_profile_init();
936 ret = register_ftrace_profiler();
941 ftrace_profile_enabled = 1;
943 ftrace_profile_enabled = 0;
945 * unregister_ftrace_profiler calls stop_machine
946 * so this acts like an synchronize_sched.
948 unregister_ftrace_profiler();
952 mutex_unlock(&ftrace_profile_lock);
960 ftrace_profile_read(struct file *filp, char __user *ubuf,
961 size_t cnt, loff_t *ppos)
963 char buf[64]; /* big enough to hold a number */
966 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
967 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
970 static const struct file_operations ftrace_profile_fops = {
971 .open = tracing_open_generic,
972 .read = ftrace_profile_read,
973 .write = ftrace_profile_write,
974 .llseek = default_llseek,
977 /* used to initialize the real stat files */
978 static struct tracer_stat function_stats __initdata = {
980 .stat_start = function_stat_start,
981 .stat_next = function_stat_next,
982 .stat_cmp = function_stat_cmp,
983 .stat_headers = function_stat_headers,
984 .stat_show = function_stat_show
987 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
989 struct ftrace_profile_stat *stat;
990 struct dentry *entry;
995 for_each_possible_cpu(cpu) {
996 stat = &per_cpu(ftrace_profile_stats, cpu);
998 /* allocate enough for function name + cpu number */
999 name = kmalloc(32, GFP_KERNEL);
1002 * The files created are permanent, if something happens
1003 * we still do not free memory.
1006 "Could not allocate stat file for cpu %d\n",
1010 stat->stat = function_stats;
1011 snprintf(name, 32, "function%d", cpu);
1012 stat->stat.name = name;
1013 ret = register_stat_tracer(&stat->stat);
1016 "Could not register function stat for cpu %d\n",
1023 entry = debugfs_create_file("function_profile_enabled", 0644,
1024 d_tracer, NULL, &ftrace_profile_fops);
1026 pr_warning("Could not create debugfs "
1027 "'function_profile_enabled' entry\n");
1030 #else /* CONFIG_FUNCTION_PROFILER */
1031 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
1034 #endif /* CONFIG_FUNCTION_PROFILER */
1036 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1038 #ifdef CONFIG_DYNAMIC_FTRACE
1040 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1041 # error Dynamic ftrace depends on MCOUNT_RECORD
1044 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
1046 struct ftrace_func_probe {
1047 struct hlist_node node;
1048 struct ftrace_probe_ops *ops;
1049 unsigned long flags;
1052 struct list_head free_list;
1055 struct ftrace_func_entry {
1056 struct hlist_node hlist;
1060 struct ftrace_hash {
1061 unsigned long size_bits;
1062 struct hlist_head *buckets;
1063 unsigned long count;
1064 struct rcu_head rcu;
1068 * We make these constant because no one should touch them,
1069 * but they are used as the default "empty hash", to avoid allocating
1070 * it all the time. These are in a read only section such that if
1071 * anyone does try to modify it, it will cause an exception.
1073 static const struct hlist_head empty_buckets[1];
1074 static const struct ftrace_hash empty_hash = {
1075 .buckets = (struct hlist_head *)empty_buckets,
1077 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1079 static struct ftrace_ops global_ops = {
1080 .func = ftrace_stub,
1081 .notrace_hash = EMPTY_HASH,
1082 .filter_hash = EMPTY_HASH,
1083 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
1084 INIT_REGEX_LOCK(global_ops)
1087 struct ftrace_page {
1088 struct ftrace_page *next;
1089 struct dyn_ftrace *records;
1094 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1095 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1097 /* estimate from running different kernels */
1098 #define NR_TO_INIT 10000
1100 static struct ftrace_page *ftrace_pages_start;
1101 static struct ftrace_page *ftrace_pages;
1103 static bool ftrace_hash_empty(struct ftrace_hash *hash)
1105 return !hash || !hash->count;
1108 static struct ftrace_func_entry *
1109 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1112 struct ftrace_func_entry *entry;
1113 struct hlist_head *hhd;
1115 if (ftrace_hash_empty(hash))
1118 if (hash->size_bits > 0)
1119 key = hash_long(ip, hash->size_bits);
1123 hhd = &hash->buckets[key];
1125 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1126 if (entry->ip == ip)
1132 static void __add_hash_entry(struct ftrace_hash *hash,
1133 struct ftrace_func_entry *entry)
1135 struct hlist_head *hhd;
1138 if (hash->size_bits)
1139 key = hash_long(entry->ip, hash->size_bits);
1143 hhd = &hash->buckets[key];
1144 hlist_add_head(&entry->hlist, hhd);
1148 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1150 struct ftrace_func_entry *entry;
1152 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1157 __add_hash_entry(hash, entry);
1163 free_hash_entry(struct ftrace_hash *hash,
1164 struct ftrace_func_entry *entry)
1166 hlist_del(&entry->hlist);
1172 remove_hash_entry(struct ftrace_hash *hash,
1173 struct ftrace_func_entry *entry)
1175 hlist_del(&entry->hlist);
1179 static void ftrace_hash_clear(struct ftrace_hash *hash)
1181 struct hlist_head *hhd;
1182 struct hlist_node *tn;
1183 struct ftrace_func_entry *entry;
1184 int size = 1 << hash->size_bits;
1190 for (i = 0; i < size; i++) {
1191 hhd = &hash->buckets[i];
1192 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1193 free_hash_entry(hash, entry);
1195 FTRACE_WARN_ON(hash->count);
1198 static void free_ftrace_hash(struct ftrace_hash *hash)
1200 if (!hash || hash == EMPTY_HASH)
1202 ftrace_hash_clear(hash);
1203 kfree(hash->buckets);
1207 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1209 struct ftrace_hash *hash;
1211 hash = container_of(rcu, struct ftrace_hash, rcu);
1212 free_ftrace_hash(hash);
1215 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1217 if (!hash || hash == EMPTY_HASH)
1219 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1222 void ftrace_free_filter(struct ftrace_ops *ops)
1224 ftrace_ops_init(ops);
1225 free_ftrace_hash(ops->filter_hash);
1226 free_ftrace_hash(ops->notrace_hash);
1229 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1231 struct ftrace_hash *hash;
1234 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1238 size = 1 << size_bits;
1239 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1241 if (!hash->buckets) {
1246 hash->size_bits = size_bits;
1251 static struct ftrace_hash *
1252 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1254 struct ftrace_func_entry *entry;
1255 struct ftrace_hash *new_hash;
1260 new_hash = alloc_ftrace_hash(size_bits);
1265 if (ftrace_hash_empty(hash))
1268 size = 1 << hash->size_bits;
1269 for (i = 0; i < size; i++) {
1270 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1271 ret = add_hash_entry(new_hash, entry->ip);
1277 FTRACE_WARN_ON(new_hash->count != hash->count);
1282 free_ftrace_hash(new_hash);
1287 ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash);
1289 ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash);
1292 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1293 struct ftrace_hash **dst, struct ftrace_hash *src)
1295 struct ftrace_func_entry *entry;
1296 struct hlist_node *tn;
1297 struct hlist_head *hhd;
1298 struct ftrace_hash *old_hash;
1299 struct ftrace_hash *new_hash;
1300 int size = src->count;
1306 * Remove the current set, update the hash and add
1309 ftrace_hash_rec_disable(ops, enable);
1312 * If the new source is empty, just free dst and assign it
1316 free_ftrace_hash_rcu(*dst);
1317 rcu_assign_pointer(*dst, EMPTY_HASH);
1318 /* still need to update the function records */
1324 * Make the hash size about 1/2 the # found
1326 for (size /= 2; size; size >>= 1)
1329 /* Don't allocate too much */
1330 if (bits > FTRACE_HASH_MAX_BITS)
1331 bits = FTRACE_HASH_MAX_BITS;
1334 new_hash = alloc_ftrace_hash(bits);
1338 size = 1 << src->size_bits;
1339 for (i = 0; i < size; i++) {
1340 hhd = &src->buckets[i];
1341 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1342 remove_hash_entry(src, entry);
1343 __add_hash_entry(new_hash, entry);
1348 rcu_assign_pointer(*dst, new_hash);
1349 free_ftrace_hash_rcu(old_hash);
1354 * Enable regardless of ret:
1355 * On success, we enable the new hash.
1356 * On failure, we re-enable the original hash.
1358 ftrace_hash_rec_enable(ops, enable);
1364 * Test the hashes for this ops to see if we want to call
1365 * the ops->func or not.
1367 * It's a match if the ip is in the ops->filter_hash or
1368 * the filter_hash does not exist or is empty,
1370 * the ip is not in the ops->notrace_hash.
1372 * This needs to be called with preemption disabled as
1373 * the hashes are freed with call_rcu_sched().
1376 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1378 struct ftrace_hash *filter_hash;
1379 struct ftrace_hash *notrace_hash;
1382 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1384 * There's a small race when adding ops that the ftrace handler
1385 * that wants regs, may be called without them. We can not
1386 * allow that handler to be called if regs is NULL.
1388 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1392 filter_hash = rcu_dereference_raw_notrace(ops->filter_hash);
1393 notrace_hash = rcu_dereference_raw_notrace(ops->notrace_hash);
1395 if ((ftrace_hash_empty(filter_hash) ||
1396 ftrace_lookup_ip(filter_hash, ip)) &&
1397 (ftrace_hash_empty(notrace_hash) ||
1398 !ftrace_lookup_ip(notrace_hash, ip)))
1407 * This is a double for. Do not use 'break' to break out of the loop,
1408 * you must use a goto.
1410 #define do_for_each_ftrace_rec(pg, rec) \
1411 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1413 for (_____i = 0; _____i < pg->index; _____i++) { \
1414 rec = &pg->records[_____i];
1416 #define while_for_each_ftrace_rec() \
1421 static int ftrace_cmp_recs(const void *a, const void *b)
1423 const struct dyn_ftrace *key = a;
1424 const struct dyn_ftrace *rec = b;
1426 if (key->flags < rec->ip)
1428 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1433 static unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1435 struct ftrace_page *pg;
1436 struct dyn_ftrace *rec;
1437 struct dyn_ftrace key;
1440 key.flags = end; /* overload flags, as it is unsigned long */
1442 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1443 if (end < pg->records[0].ip ||
1444 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1446 rec = bsearch(&key, pg->records, pg->index,
1447 sizeof(struct dyn_ftrace),
1457 * ftrace_location - return true if the ip giving is a traced location
1458 * @ip: the instruction pointer to check
1460 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1461 * That is, the instruction that is either a NOP or call to
1462 * the function tracer. It checks the ftrace internal tables to
1463 * determine if the address belongs or not.
1465 unsigned long ftrace_location(unsigned long ip)
1467 return ftrace_location_range(ip, ip);
1471 * ftrace_text_reserved - return true if range contains an ftrace location
1472 * @start: start of range to search
1473 * @end: end of range to search (inclusive). @end points to the last byte to check.
1475 * Returns 1 if @start and @end contains a ftrace location.
1476 * That is, the instruction that is either a NOP or call to
1477 * the function tracer. It checks the ftrace internal tables to
1478 * determine if the address belongs or not.
1480 int ftrace_text_reserved(const void *start, const void *end)
1484 ret = ftrace_location_range((unsigned long)start,
1485 (unsigned long)end);
1490 static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
1494 struct ftrace_hash *hash;
1495 struct ftrace_hash *other_hash;
1496 struct ftrace_page *pg;
1497 struct dyn_ftrace *rec;
1501 /* Only update if the ops has been registered */
1502 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1506 * In the filter_hash case:
1507 * If the count is zero, we update all records.
1508 * Otherwise we just update the items in the hash.
1510 * In the notrace_hash case:
1511 * We enable the update in the hash.
1512 * As disabling notrace means enabling the tracing,
1513 * and enabling notrace means disabling, the inc variable
1517 hash = ops->filter_hash;
1518 other_hash = ops->notrace_hash;
1519 if (ftrace_hash_empty(hash))
1523 hash = ops->notrace_hash;
1524 other_hash = ops->filter_hash;
1526 * If the notrace hash has no items,
1527 * then there's nothing to do.
1529 if (ftrace_hash_empty(hash))
1533 do_for_each_ftrace_rec(pg, rec) {
1534 int in_other_hash = 0;
1540 * Only the filter_hash affects all records.
1541 * Update if the record is not in the notrace hash.
1543 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1546 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1547 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1552 if (filter_hash && in_hash && !in_other_hash)
1554 else if (!filter_hash && in_hash &&
1555 (in_other_hash || ftrace_hash_empty(other_hash)))
1563 if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX))
1566 * If any ops wants regs saved for this function
1567 * then all ops will get saved regs.
1569 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1570 rec->flags |= FTRACE_FL_REGS;
1572 if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
1577 /* Shortcut, if we handled all records, we are done. */
1578 if (!all && count == hash->count)
1580 } while_for_each_ftrace_rec();
1583 static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
1586 __ftrace_hash_rec_update(ops, filter_hash, 0);
1589 static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
1592 __ftrace_hash_rec_update(ops, filter_hash, 1);
1595 static void print_ip_ins(const char *fmt, unsigned char *p)
1599 printk(KERN_CONT "%s", fmt);
1601 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1602 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1606 * ftrace_bug - report and shutdown function tracer
1607 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1608 * @ip: The address that failed
1610 * The arch code that enables or disables the function tracing
1611 * can call ftrace_bug() when it has detected a problem in
1612 * modifying the code. @failed should be one of either:
1613 * EFAULT - if the problem happens on reading the @ip address
1614 * EINVAL - if what is read at @ip is not what was expected
1615 * EPERM - if the problem happens on writting to the @ip address
1617 void ftrace_bug(int failed, unsigned long ip)
1621 FTRACE_WARN_ON_ONCE(1);
1622 pr_info("ftrace faulted on modifying ");
1626 FTRACE_WARN_ON_ONCE(1);
1627 pr_info("ftrace failed to modify ");
1629 print_ip_ins(" actual: ", (unsigned char *)ip);
1630 printk(KERN_CONT "\n");
1633 FTRACE_WARN_ON_ONCE(1);
1634 pr_info("ftrace faulted on writing ");
1638 FTRACE_WARN_ON_ONCE(1);
1639 pr_info("ftrace faulted on unknown error ");
1644 static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
1646 unsigned long flag = 0UL;
1649 * If we are updating calls:
1651 * If the record has a ref count, then we need to enable it
1652 * because someone is using it.
1654 * Otherwise we make sure its disabled.
1656 * If we are disabling calls, then disable all records that
1659 if (enable && (rec->flags & ~FTRACE_FL_MASK))
1660 flag = FTRACE_FL_ENABLED;
1663 * If enabling and the REGS flag does not match the REGS_EN, then
1664 * do not ignore this record. Set flags to fail the compare against
1668 (!(rec->flags & FTRACE_FL_REGS) != !(rec->flags & FTRACE_FL_REGS_EN)))
1669 flag |= FTRACE_FL_REGS;
1671 /* If the state of this record hasn't changed, then do nothing */
1672 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1673 return FTRACE_UPDATE_IGNORE;
1676 /* Save off if rec is being enabled (for return value) */
1677 flag ^= rec->flags & FTRACE_FL_ENABLED;
1680 rec->flags |= FTRACE_FL_ENABLED;
1681 if (flag & FTRACE_FL_REGS) {
1682 if (rec->flags & FTRACE_FL_REGS)
1683 rec->flags |= FTRACE_FL_REGS_EN;
1685 rec->flags &= ~FTRACE_FL_REGS_EN;
1690 * If this record is being updated from a nop, then
1691 * return UPDATE_MAKE_CALL.
1692 * Otherwise, if the EN flag is set, then return
1693 * UPDATE_MODIFY_CALL_REGS to tell the caller to convert
1694 * from the non-save regs, to a save regs function.
1696 * return UPDATE_MODIFY_CALL to tell the caller to convert
1697 * from the save regs, to a non-save regs function.
1699 if (flag & FTRACE_FL_ENABLED)
1700 return FTRACE_UPDATE_MAKE_CALL;
1701 else if (rec->flags & FTRACE_FL_REGS_EN)
1702 return FTRACE_UPDATE_MODIFY_CALL_REGS;
1704 return FTRACE_UPDATE_MODIFY_CALL;
1708 /* If there's no more users, clear all flags */
1709 if (!(rec->flags & ~FTRACE_FL_MASK))
1712 /* Just disable the record (keep REGS state) */
1713 rec->flags &= ~FTRACE_FL_ENABLED;
1716 return FTRACE_UPDATE_MAKE_NOP;
1720 * ftrace_update_record, set a record that now is tracing or not
1721 * @rec: the record to update
1722 * @enable: set to 1 if the record is tracing, zero to force disable
1724 * The records that represent all functions that can be traced need
1725 * to be updated when tracing has been enabled.
1727 int ftrace_update_record(struct dyn_ftrace *rec, int enable)
1729 return ftrace_check_record(rec, enable, 1);
1733 * ftrace_test_record, check if the record has been enabled or not
1734 * @rec: the record to test
1735 * @enable: set to 1 to check if enabled, 0 if it is disabled
1737 * The arch code may need to test if a record is already set to
1738 * tracing to determine how to modify the function code that it
1741 int ftrace_test_record(struct dyn_ftrace *rec, int enable)
1743 return ftrace_check_record(rec, enable, 0);
1747 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1749 unsigned long ftrace_old_addr;
1750 unsigned long ftrace_addr;
1753 ret = ftrace_update_record(rec, enable);
1755 if (rec->flags & FTRACE_FL_REGS)
1756 ftrace_addr = (unsigned long)FTRACE_REGS_ADDR;
1758 ftrace_addr = (unsigned long)FTRACE_ADDR;
1761 case FTRACE_UPDATE_IGNORE:
1764 case FTRACE_UPDATE_MAKE_CALL:
1765 return ftrace_make_call(rec, ftrace_addr);
1767 case FTRACE_UPDATE_MAKE_NOP:
1768 return ftrace_make_nop(NULL, rec, ftrace_addr);
1770 case FTRACE_UPDATE_MODIFY_CALL_REGS:
1771 case FTRACE_UPDATE_MODIFY_CALL:
1772 if (rec->flags & FTRACE_FL_REGS)
1773 ftrace_old_addr = (unsigned long)FTRACE_ADDR;
1775 ftrace_old_addr = (unsigned long)FTRACE_REGS_ADDR;
1777 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
1780 return -1; /* unknow ftrace bug */
1783 void __weak ftrace_replace_code(int enable)
1785 struct dyn_ftrace *rec;
1786 struct ftrace_page *pg;
1789 if (unlikely(ftrace_disabled))
1792 do_for_each_ftrace_rec(pg, rec) {
1793 failed = __ftrace_replace_code(rec, enable);
1795 ftrace_bug(failed, rec->ip);
1796 /* Stop processing */
1799 } while_for_each_ftrace_rec();
1802 struct ftrace_rec_iter {
1803 struct ftrace_page *pg;
1808 * ftrace_rec_iter_start, start up iterating over traced functions
1810 * Returns an iterator handle that is used to iterate over all
1811 * the records that represent address locations where functions
1814 * May return NULL if no records are available.
1816 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
1819 * We only use a single iterator.
1820 * Protected by the ftrace_lock mutex.
1822 static struct ftrace_rec_iter ftrace_rec_iter;
1823 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
1825 iter->pg = ftrace_pages_start;
1828 /* Could have empty pages */
1829 while (iter->pg && !iter->pg->index)
1830 iter->pg = iter->pg->next;
1839 * ftrace_rec_iter_next, get the next record to process.
1840 * @iter: The handle to the iterator.
1842 * Returns the next iterator after the given iterator @iter.
1844 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
1848 if (iter->index >= iter->pg->index) {
1849 iter->pg = iter->pg->next;
1852 /* Could have empty pages */
1853 while (iter->pg && !iter->pg->index)
1854 iter->pg = iter->pg->next;
1864 * ftrace_rec_iter_record, get the record at the iterator location
1865 * @iter: The current iterator location
1867 * Returns the record that the current @iter is at.
1869 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
1871 return &iter->pg->records[iter->index];
1875 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1882 if (unlikely(ftrace_disabled))
1885 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1887 ftrace_bug(ret, ip);
1894 * archs can override this function if they must do something
1895 * before the modifying code is performed.
1897 int __weak ftrace_arch_code_modify_prepare(void)
1903 * archs can override this function if they must do something
1904 * after the modifying code is performed.
1906 int __weak ftrace_arch_code_modify_post_process(void)
1911 void ftrace_modify_all_code(int command)
1913 int update = command & FTRACE_UPDATE_TRACE_FUNC;
1917 * If the ftrace_caller calls a ftrace_ops func directly,
1918 * we need to make sure that it only traces functions it
1919 * expects to trace. When doing the switch of functions,
1920 * we need to update to the ftrace_ops_list_func first
1921 * before the transition between old and new calls are set,
1922 * as the ftrace_ops_list_func will check the ops hashes
1923 * to make sure the ops are having the right functions
1927 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
1928 if (FTRACE_WARN_ON(err))
1932 if (command & FTRACE_UPDATE_CALLS)
1933 ftrace_replace_code(1);
1934 else if (command & FTRACE_DISABLE_CALLS)
1935 ftrace_replace_code(0);
1937 if (update && ftrace_trace_function != ftrace_ops_list_func) {
1938 function_trace_op = set_function_trace_op;
1940 /* If irqs are disabled, we are in stop machine */
1941 if (!irqs_disabled())
1942 smp_call_function(ftrace_sync_ipi, NULL, 1);
1943 err = ftrace_update_ftrace_func(ftrace_trace_function);
1944 if (FTRACE_WARN_ON(err))
1948 if (command & FTRACE_START_FUNC_RET)
1949 err = ftrace_enable_ftrace_graph_caller();
1950 else if (command & FTRACE_STOP_FUNC_RET)
1951 err = ftrace_disable_ftrace_graph_caller();
1952 FTRACE_WARN_ON(err);
1955 static int __ftrace_modify_code(void *data)
1957 int *command = data;
1959 ftrace_modify_all_code(*command);
1965 * ftrace_run_stop_machine, go back to the stop machine method
1966 * @command: The command to tell ftrace what to do
1968 * If an arch needs to fall back to the stop machine method, the
1969 * it can call this function.
1971 void ftrace_run_stop_machine(int command)
1973 stop_machine(__ftrace_modify_code, &command, NULL);
1977 * arch_ftrace_update_code, modify the code to trace or not trace
1978 * @command: The command that needs to be done
1980 * Archs can override this function if it does not need to
1981 * run stop_machine() to modify code.
1983 void __weak arch_ftrace_update_code(int command)
1985 ftrace_run_stop_machine(command);
1988 static void ftrace_run_update_code(int command)
1992 ret = ftrace_arch_code_modify_prepare();
1993 FTRACE_WARN_ON(ret);
1997 * Do not call function tracer while we update the code.
1998 * We are in stop machine.
2000 function_trace_stop++;
2003 * By default we use stop_machine() to modify the code.
2004 * But archs can do what ever they want as long as it
2005 * is safe. The stop_machine() is the safest, but also
2006 * produces the most overhead.
2008 arch_ftrace_update_code(command);
2010 function_trace_stop--;
2012 ret = ftrace_arch_code_modify_post_process();
2013 FTRACE_WARN_ON(ret);
2016 static ftrace_func_t saved_ftrace_func;
2017 static int ftrace_start_up;
2018 static int global_start_up;
2020 static void control_ops_free(struct ftrace_ops *ops)
2022 free_percpu(ops->disabled);
2025 static void ftrace_startup_enable(int command)
2027 if (saved_ftrace_func != ftrace_trace_function) {
2028 saved_ftrace_func = ftrace_trace_function;
2029 command |= FTRACE_UPDATE_TRACE_FUNC;
2032 if (!command || !ftrace_enabled)
2035 ftrace_run_update_code(command);
2038 static int ftrace_startup(struct ftrace_ops *ops, int command)
2040 bool hash_enable = true;
2043 if (unlikely(ftrace_disabled))
2046 ret = __register_ftrace_function(ops);
2051 command |= FTRACE_UPDATE_CALLS;
2053 ops->flags |= FTRACE_OPS_FL_ENABLED;
2055 ftrace_hash_rec_enable(ops, 1);
2057 ftrace_startup_enable(command);
2062 static int ftrace_shutdown(struct ftrace_ops *ops, int command)
2064 bool hash_disable = true;
2067 if (unlikely(ftrace_disabled))
2070 ret = __unregister_ftrace_function(ops);
2076 * Just warn in case of unbalance, no need to kill ftrace, it's not
2077 * critical but the ftrace_call callers may be never nopped again after
2078 * further ftrace uses.
2080 WARN_ON_ONCE(ftrace_start_up < 0);
2083 ftrace_hash_rec_disable(ops, 1);
2085 if (!global_start_up)
2086 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2088 command |= FTRACE_UPDATE_CALLS;
2090 if (saved_ftrace_func != ftrace_trace_function) {
2091 saved_ftrace_func = ftrace_trace_function;
2092 command |= FTRACE_UPDATE_TRACE_FUNC;
2095 if (!command || !ftrace_enabled) {
2097 * If these are control ops, they still need their
2098 * per_cpu field freed. Since, function tracing is
2099 * not currently active, we can just free them
2100 * without synchronizing all CPUs.
2102 if (ops->flags & FTRACE_OPS_FL_CONTROL)
2103 control_ops_free(ops);
2107 ftrace_run_update_code(command);
2110 * Dynamic ops may be freed, we must make sure that all
2111 * callers are done before leaving this function.
2112 * The same goes for freeing the per_cpu data of the control
2115 * Again, normal synchronize_sched() is not good enough.
2116 * We need to do a hard force of sched synchronization.
2117 * This is because we use preempt_disable() to do RCU, but
2118 * the function tracers can be called where RCU is not watching
2119 * (like before user_exit()). We can not rely on the RCU
2120 * infrastructure to do the synchronization, thus we must do it
2123 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_CONTROL)) {
2124 schedule_on_each_cpu(ftrace_sync);
2126 if (ops->flags & FTRACE_OPS_FL_CONTROL)
2127 control_ops_free(ops);
2133 static void ftrace_startup_sysctl(void)
2135 if (unlikely(ftrace_disabled))
2138 /* Force update next time */
2139 saved_ftrace_func = NULL;
2140 /* ftrace_start_up is true if we want ftrace running */
2141 if (ftrace_start_up)
2142 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
2145 static void ftrace_shutdown_sysctl(void)
2147 if (unlikely(ftrace_disabled))
2150 /* ftrace_start_up is true if ftrace is running */
2151 if (ftrace_start_up)
2152 ftrace_run_update_code(FTRACE_DISABLE_CALLS);
2155 static cycle_t ftrace_update_time;
2156 unsigned long ftrace_update_tot_cnt;
2158 static inline int ops_traces_mod(struct ftrace_ops *ops)
2161 * Filter_hash being empty will default to trace module.
2162 * But notrace hash requires a test of individual module functions.
2164 return ftrace_hash_empty(ops->filter_hash) &&
2165 ftrace_hash_empty(ops->notrace_hash);
2169 * Check if the current ops references the record.
2171 * If the ops traces all functions, then it was already accounted for.
2172 * If the ops does not trace the current record function, skip it.
2173 * If the ops ignores the function via notrace filter, skip it.
2176 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2178 /* If ops isn't enabled, ignore it */
2179 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2182 /* If ops traces all mods, we already accounted for it */
2183 if (ops_traces_mod(ops))
2186 /* The function must be in the filter */
2187 if (!ftrace_hash_empty(ops->filter_hash) &&
2188 !ftrace_lookup_ip(ops->filter_hash, rec->ip))
2191 /* If in notrace hash, we ignore it too */
2192 if (ftrace_lookup_ip(ops->notrace_hash, rec->ip))
2198 static int referenced_filters(struct dyn_ftrace *rec)
2200 struct ftrace_ops *ops;
2203 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
2204 if (ops_references_rec(ops, rec))
2211 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
2213 struct ftrace_page *pg;
2214 struct dyn_ftrace *p;
2215 cycle_t start, stop;
2216 unsigned long update_cnt = 0;
2217 unsigned long ref = 0;
2222 * When adding a module, we need to check if tracers are
2223 * currently enabled and if they are set to trace all functions.
2224 * If they are, we need to enable the module functions as well
2225 * as update the reference counts for those function records.
2228 struct ftrace_ops *ops;
2230 for (ops = ftrace_ops_list;
2231 ops != &ftrace_list_end; ops = ops->next) {
2232 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
2233 if (ops_traces_mod(ops))
2241 start = ftrace_now(raw_smp_processor_id());
2243 for (pg = new_pgs; pg; pg = pg->next) {
2245 for (i = 0; i < pg->index; i++) {
2248 /* If something went wrong, bail without enabling anything */
2249 if (unlikely(ftrace_disabled))
2252 p = &pg->records[i];
2254 cnt += referenced_filters(p);
2258 * Do the initial record conversion from mcount jump
2259 * to the NOP instructions.
2261 if (!ftrace_code_disable(mod, p))
2267 * If the tracing is enabled, go ahead and enable the record.
2269 * The reason not to enable the record immediatelly is the
2270 * inherent check of ftrace_make_nop/ftrace_make_call for
2271 * correct previous instructions. Making first the NOP
2272 * conversion puts the module to the correct state, thus
2273 * passing the ftrace_make_call check.
2275 if (ftrace_start_up && cnt) {
2276 int failed = __ftrace_replace_code(p, 1);
2278 ftrace_bug(failed, p->ip);
2283 stop = ftrace_now(raw_smp_processor_id());
2284 ftrace_update_time = stop - start;
2285 ftrace_update_tot_cnt += update_cnt;
2290 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2295 if (WARN_ON(!count))
2298 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2301 * We want to fill as much as possible. No more than a page
2304 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2308 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2311 /* if we can't allocate this size, try something smaller */
2318 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2327 static struct ftrace_page *
2328 ftrace_allocate_pages(unsigned long num_to_init)
2330 struct ftrace_page *start_pg;
2331 struct ftrace_page *pg;
2338 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
2343 * Try to allocate as much as possible in one continues
2344 * location that fills in all of the space. We want to
2345 * waste as little space as possible.
2348 cnt = ftrace_allocate_records(pg, num_to_init);
2356 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
2367 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
2368 free_pages((unsigned long)pg->records, order);
2369 start_pg = pg->next;
2373 pr_info("ftrace: FAILED to allocate memory for functions\n");
2377 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
2379 struct ftrace_iterator {
2382 struct ftrace_page *pg;
2383 struct dyn_ftrace *func;
2384 struct ftrace_func_probe *probe;
2385 struct trace_parser parser;
2386 struct ftrace_hash *hash;
2387 struct ftrace_ops *ops;
2394 t_hash_next(struct seq_file *m, loff_t *pos)
2396 struct ftrace_iterator *iter = m->private;
2397 struct hlist_node *hnd = NULL;
2398 struct hlist_head *hhd;
2404 hnd = &iter->probe->node;
2406 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
2409 hhd = &ftrace_func_hash[iter->hidx];
2411 if (hlist_empty(hhd)) {
2427 if (WARN_ON_ONCE(!hnd))
2430 iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
2435 static void *t_hash_start(struct seq_file *m, loff_t *pos)
2437 struct ftrace_iterator *iter = m->private;
2441 if (!(iter->flags & FTRACE_ITER_DO_HASH))
2444 if (iter->func_pos > *pos)
2448 for (l = 0; l <= (*pos - iter->func_pos); ) {
2449 p = t_hash_next(m, &l);
2456 /* Only set this if we have an item */
2457 iter->flags |= FTRACE_ITER_HASH;
2463 t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
2465 struct ftrace_func_probe *rec;
2468 if (WARN_ON_ONCE(!rec))
2471 if (rec->ops->print)
2472 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
2474 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
2477 seq_printf(m, ":%p", rec->data);
2484 t_next(struct seq_file *m, void *v, loff_t *pos)
2486 struct ftrace_iterator *iter = m->private;
2487 struct ftrace_ops *ops = iter->ops;
2488 struct dyn_ftrace *rec = NULL;
2490 if (unlikely(ftrace_disabled))
2493 if (iter->flags & FTRACE_ITER_HASH)
2494 return t_hash_next(m, pos);
2497 iter->pos = iter->func_pos = *pos;
2499 if (iter->flags & FTRACE_ITER_PRINTALL)
2500 return t_hash_start(m, pos);
2503 if (iter->idx >= iter->pg->index) {
2504 if (iter->pg->next) {
2505 iter->pg = iter->pg->next;
2510 rec = &iter->pg->records[iter->idx++];
2511 if (((iter->flags & FTRACE_ITER_FILTER) &&
2512 !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||
2514 ((iter->flags & FTRACE_ITER_NOTRACE) &&
2515 !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
2517 ((iter->flags & FTRACE_ITER_ENABLED) &&
2518 !(rec->flags & FTRACE_FL_ENABLED))) {
2526 return t_hash_start(m, pos);
2533 static void reset_iter_read(struct ftrace_iterator *iter)
2537 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_HASH);
2540 static void *t_start(struct seq_file *m, loff_t *pos)
2542 struct ftrace_iterator *iter = m->private;
2543 struct ftrace_ops *ops = iter->ops;
2547 mutex_lock(&ftrace_lock);
2549 if (unlikely(ftrace_disabled))
2553 * If an lseek was done, then reset and start from beginning.
2555 if (*pos < iter->pos)
2556 reset_iter_read(iter);
2559 * For set_ftrace_filter reading, if we have the filter
2560 * off, we can short cut and just print out that all
2561 * functions are enabled.
2563 if (iter->flags & FTRACE_ITER_FILTER &&
2564 ftrace_hash_empty(ops->filter_hash)) {
2566 return t_hash_start(m, pos);
2567 iter->flags |= FTRACE_ITER_PRINTALL;
2568 /* reset in case of seek/pread */
2569 iter->flags &= ~FTRACE_ITER_HASH;
2573 if (iter->flags & FTRACE_ITER_HASH)
2574 return t_hash_start(m, pos);
2577 * Unfortunately, we need to restart at ftrace_pages_start
2578 * every time we let go of the ftrace_mutex. This is because
2579 * those pointers can change without the lock.
2581 iter->pg = ftrace_pages_start;
2583 for (l = 0; l <= *pos; ) {
2584 p = t_next(m, p, &l);
2590 return t_hash_start(m, pos);
2595 static void t_stop(struct seq_file *m, void *p)
2597 mutex_unlock(&ftrace_lock);
2600 static int t_show(struct seq_file *m, void *v)
2602 struct ftrace_iterator *iter = m->private;
2603 struct dyn_ftrace *rec;
2605 if (iter->flags & FTRACE_ITER_HASH)
2606 return t_hash_show(m, iter);
2608 if (iter->flags & FTRACE_ITER_PRINTALL) {
2609 seq_printf(m, "#### all functions enabled ####\n");
2618 seq_printf(m, "%ps", (void *)rec->ip);
2619 if (iter->flags & FTRACE_ITER_ENABLED)
2620 seq_printf(m, " (%ld)%s",
2621 rec->flags & ~FTRACE_FL_MASK,
2622 rec->flags & FTRACE_FL_REGS ? " R" : "");
2623 seq_printf(m, "\n");
2628 static const struct seq_operations show_ftrace_seq_ops = {
2636 ftrace_avail_open(struct inode *inode, struct file *file)
2638 struct ftrace_iterator *iter;
2640 if (unlikely(ftrace_disabled))
2643 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
2645 iter->pg = ftrace_pages_start;
2646 iter->ops = &global_ops;
2649 return iter ? 0 : -ENOMEM;
2653 ftrace_enabled_open(struct inode *inode, struct file *file)
2655 struct ftrace_iterator *iter;
2657 if (unlikely(ftrace_disabled))
2660 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
2662 iter->pg = ftrace_pages_start;
2663 iter->flags = FTRACE_ITER_ENABLED;
2664 iter->ops = &global_ops;
2667 return iter ? 0 : -ENOMEM;
2670 static void ftrace_filter_reset(struct ftrace_hash *hash)
2672 mutex_lock(&ftrace_lock);
2673 ftrace_hash_clear(hash);
2674 mutex_unlock(&ftrace_lock);
2678 * ftrace_regex_open - initialize function tracer filter files
2679 * @ops: The ftrace_ops that hold the hash filters
2680 * @flag: The type of filter to process
2681 * @inode: The inode, usually passed in to your open routine
2682 * @file: The file, usually passed in to your open routine
2684 * ftrace_regex_open() initializes the filter files for the
2685 * @ops. Depending on @flag it may process the filter hash or
2686 * the notrace hash of @ops. With this called from the open
2687 * routine, you can use ftrace_filter_write() for the write
2688 * routine if @flag has FTRACE_ITER_FILTER set, or
2689 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
2690 * tracing_lseek() should be used as the lseek routine, and
2691 * release must call ftrace_regex_release().
2694 ftrace_regex_open(struct ftrace_ops *ops, int flag,
2695 struct inode *inode, struct file *file)
2697 struct ftrace_iterator *iter;
2698 struct ftrace_hash *hash;
2701 ftrace_ops_init(ops);
2703 if (unlikely(ftrace_disabled))
2706 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2710 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
2718 mutex_lock(&ops->regex_lock);
2720 if (flag & FTRACE_ITER_NOTRACE)
2721 hash = ops->notrace_hash;
2723 hash = ops->filter_hash;
2725 if (file->f_mode & FMODE_WRITE) {
2726 iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
2728 trace_parser_put(&iter->parser);
2735 if ((file->f_mode & FMODE_WRITE) &&
2736 (file->f_flags & O_TRUNC))
2737 ftrace_filter_reset(iter->hash);
2739 if (file->f_mode & FMODE_READ) {
2740 iter->pg = ftrace_pages_start;
2742 ret = seq_open(file, &show_ftrace_seq_ops);
2744 struct seq_file *m = file->private_data;
2748 free_ftrace_hash(iter->hash);
2749 trace_parser_put(&iter->parser);
2753 file->private_data = iter;
2756 mutex_unlock(&ops->regex_lock);
2762 ftrace_filter_open(struct inode *inode, struct file *file)
2764 struct ftrace_ops *ops = inode->i_private;
2766 return ftrace_regex_open(ops,
2767 FTRACE_ITER_FILTER | FTRACE_ITER_DO_HASH,
2772 ftrace_notrace_open(struct inode *inode, struct file *file)
2774 struct ftrace_ops *ops = inode->i_private;
2776 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
2780 static int ftrace_match(char *str, char *regex, int len, int type)
2787 if (strcmp(str, regex) == 0)
2790 case MATCH_FRONT_ONLY:
2791 if (strncmp(str, regex, len) == 0)
2794 case MATCH_MIDDLE_ONLY:
2795 if (strstr(str, regex))
2798 case MATCH_END_ONLY:
2800 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
2809 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
2811 struct ftrace_func_entry *entry;
2814 entry = ftrace_lookup_ip(hash, rec->ip);
2816 /* Do nothing if it doesn't exist */
2820 free_hash_entry(hash, entry);
2822 /* Do nothing if it exists */
2826 ret = add_hash_entry(hash, rec->ip);
2832 ftrace_match_record(struct dyn_ftrace *rec, char *mod,
2833 char *regex, int len, int type)
2835 char str[KSYM_SYMBOL_LEN];
2838 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
2841 /* module lookup requires matching the module */
2842 if (!modname || strcmp(modname, mod))
2845 /* blank search means to match all funcs in the mod */
2850 return ftrace_match(str, regex, len, type);
2854 match_records(struct ftrace_hash *hash, char *buff,
2855 int len, char *mod, int not)
2857 unsigned search_len = 0;
2858 struct ftrace_page *pg;
2859 struct dyn_ftrace *rec;
2860 int type = MATCH_FULL;
2861 char *search = buff;
2866 type = filter_parse_regex(buff, len, &search, ¬);
2867 search_len = strlen(search);
2870 mutex_lock(&ftrace_lock);
2872 if (unlikely(ftrace_disabled))
2875 do_for_each_ftrace_rec(pg, rec) {
2876 if (ftrace_match_record(rec, mod, search, search_len, type)) {
2877 ret = enter_record(hash, rec, not);
2884 } while_for_each_ftrace_rec();
2886 mutex_unlock(&ftrace_lock);
2892 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
2894 return match_records(hash, buff, len, NULL, 0);
2898 ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
2902 /* blank or '*' mean the same */
2903 if (strcmp(buff, "*") == 0)
2906 /* handle the case of 'dont filter this module' */
2907 if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
2912 return match_records(hash, buff, strlen(buff), mod, not);
2916 * We register the module command as a template to show others how
2917 * to register the a command as well.
2921 ftrace_mod_callback(struct ftrace_hash *hash,
2922 char *func, char *cmd, char *param, int enable)
2928 * cmd == 'mod' because we only registered this func
2929 * for the 'mod' ftrace_func_command.
2930 * But if you register one func with multiple commands,
2931 * you can tell which command was used by the cmd
2935 /* we must have a module name */
2939 mod = strsep(¶m, ":");
2943 ret = ftrace_match_module_records(hash, func, mod);
2952 static struct ftrace_func_command ftrace_mod_cmd = {
2954 .func = ftrace_mod_callback,
2957 static int __init ftrace_mod_cmd_init(void)
2959 return register_ftrace_command(&ftrace_mod_cmd);
2961 core_initcall(ftrace_mod_cmd_init);
2963 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
2964 struct ftrace_ops *op, struct pt_regs *pt_regs)
2966 struct ftrace_func_probe *entry;
2967 struct hlist_head *hhd;
2970 key = hash_long(ip, FTRACE_HASH_BITS);
2972 hhd = &ftrace_func_hash[key];
2974 if (hlist_empty(hhd))
2978 * Disable preemption for these calls to prevent a RCU grace
2979 * period. This syncs the hash iteration and freeing of items
2980 * on the hash. rcu_read_lock is too dangerous here.
2982 preempt_disable_notrace();
2983 hlist_for_each_entry_rcu_notrace(entry, hhd, node) {
2984 if (entry->ip == ip)
2985 entry->ops->func(ip, parent_ip, &entry->data);
2987 preempt_enable_notrace();
2990 static struct ftrace_ops trace_probe_ops __read_mostly =
2992 .func = function_trace_probe_call,
2993 .flags = FTRACE_OPS_FL_INITIALIZED,
2994 INIT_REGEX_LOCK(trace_probe_ops)
2997 static int ftrace_probe_registered;
2999 static void __enable_ftrace_function_probe(void)
3004 if (ftrace_probe_registered) {
3005 /* still need to update the function call sites */
3007 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3011 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3012 struct hlist_head *hhd = &ftrace_func_hash[i];
3016 /* Nothing registered? */
3017 if (i == FTRACE_FUNC_HASHSIZE)
3020 ret = ftrace_startup(&trace_probe_ops, 0);
3022 ftrace_probe_registered = 1;
3025 static void __disable_ftrace_function_probe(void)
3029 if (!ftrace_probe_registered)
3032 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3033 struct hlist_head *hhd = &ftrace_func_hash[i];
3038 /* no more funcs left */
3039 ftrace_shutdown(&trace_probe_ops, 0);
3041 ftrace_probe_registered = 0;
3045 static void ftrace_free_entry(struct ftrace_func_probe *entry)
3047 if (entry->ops->free)
3048 entry->ops->free(entry->ops, entry->ip, &entry->data);
3053 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3056 struct ftrace_func_probe *entry;
3057 struct ftrace_hash **orig_hash = &trace_probe_ops.filter_hash;
3058 struct ftrace_hash *hash;
3059 struct ftrace_page *pg;
3060 struct dyn_ftrace *rec;
3067 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
3068 len = strlen(search);
3070 /* we do not support '!' for function probes */
3074 mutex_lock(&trace_probe_ops.regex_lock);
3076 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3082 if (unlikely(ftrace_disabled)) {
3087 mutex_lock(&ftrace_lock);
3089 do_for_each_ftrace_rec(pg, rec) {
3091 if (!ftrace_match_record(rec, NULL, search, len, type))
3094 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
3096 /* If we did not process any, then return error */
3107 * The caller might want to do something special
3108 * for each function we find. We call the callback
3109 * to give the caller an opportunity to do so.
3112 if (ops->init(ops, rec->ip, &entry->data) < 0) {
3113 /* caller does not like this func */
3119 ret = enter_record(hash, rec, 0);
3127 entry->ip = rec->ip;
3129 key = hash_long(entry->ip, FTRACE_HASH_BITS);
3130 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
3132 } while_for_each_ftrace_rec();
3134 ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3138 __enable_ftrace_function_probe();
3141 mutex_unlock(&ftrace_lock);
3143 mutex_unlock(&trace_probe_ops.regex_lock);
3144 free_ftrace_hash(hash);
3150 PROBE_TEST_FUNC = 1,
3155 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3156 void *data, int flags)
3158 struct ftrace_func_entry *rec_entry;
3159 struct ftrace_func_probe *entry;
3160 struct ftrace_func_probe *p;
3161 struct ftrace_hash **orig_hash = &trace_probe_ops.filter_hash;
3162 struct list_head free_list;
3163 struct ftrace_hash *hash;
3164 struct hlist_node *tmp;
3165 char str[KSYM_SYMBOL_LEN];
3166 int type = MATCH_FULL;
3170 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
3175 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
3176 len = strlen(search);
3178 /* we do not support '!' for function probes */
3183 mutex_lock(&trace_probe_ops.regex_lock);
3185 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3187 /* Hmm, should report this somehow */
3190 INIT_LIST_HEAD(&free_list);
3192 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3193 struct hlist_head *hhd = &ftrace_func_hash[i];
3195 hlist_for_each_entry_safe(entry, tmp, hhd, node) {
3197 /* break up if statements for readability */
3198 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
3201 if ((flags & PROBE_TEST_DATA) && entry->data != data)
3204 /* do this last, since it is the most expensive */
3206 kallsyms_lookup(entry->ip, NULL, NULL,
3208 if (!ftrace_match(str, glob, len, type))
3212 rec_entry = ftrace_lookup_ip(hash, entry->ip);
3213 /* It is possible more than one entry had this ip */
3215 free_hash_entry(hash, rec_entry);
3217 hlist_del_rcu(&entry->node);
3218 list_add(&entry->free_list, &free_list);
3221 mutex_lock(&ftrace_lock);
3222 __disable_ftrace_function_probe();
3224 * Remove after the disable is called. Otherwise, if the last
3225 * probe is removed, a null hash means *all enabled*.
3227 ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3228 synchronize_sched();
3229 list_for_each_entry_safe(entry, p, &free_list, free_list) {
3230 list_del(&entry->free_list);
3231 ftrace_free_entry(entry);
3233 mutex_unlock(&ftrace_lock);
3236 mutex_unlock(&trace_probe_ops.regex_lock);
3237 free_ftrace_hash(hash);
3241 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3244 __unregister_ftrace_function_probe(glob, ops, data,
3245 PROBE_TEST_FUNC | PROBE_TEST_DATA);
3249 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
3251 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
3254 void unregister_ftrace_function_probe_all(char *glob)
3256 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
3259 static LIST_HEAD(ftrace_commands);
3260 static DEFINE_MUTEX(ftrace_cmd_mutex);
3263 * Currently we only register ftrace commands from __init, so mark this
3266 __init int register_ftrace_command(struct ftrace_func_command *cmd)
3268 struct ftrace_func_command *p;
3271 mutex_lock(&ftrace_cmd_mutex);
3272 list_for_each_entry(p, &ftrace_commands, list) {
3273 if (strcmp(cmd->name, p->name) == 0) {
3278 list_add(&cmd->list, &ftrace_commands);
3280 mutex_unlock(&ftrace_cmd_mutex);
3286 * Currently we only unregister ftrace commands from __init, so mark
3289 __init 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);
3415 static void ftrace_ops_update_code(struct ftrace_ops *ops)
3417 if (ops->flags & FTRACE_OPS_FL_ENABLED && ftrace_enabled)
3418 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3422 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
3423 unsigned long ip, int remove, int reset, int enable)
3425 struct ftrace_hash **orig_hash;
3426 struct ftrace_hash *hash;
3429 if (unlikely(ftrace_disabled))
3432 mutex_lock(&ops->regex_lock);
3435 orig_hash = &ops->filter_hash;
3437 orig_hash = &ops->notrace_hash;
3439 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3442 goto out_regex_unlock;
3446 ftrace_filter_reset(hash);
3447 if (buf && !ftrace_match_records(hash, buf, len)) {
3449 goto out_regex_unlock;
3452 ret = ftrace_match_addr(hash, ip, remove);
3454 goto out_regex_unlock;
3457 mutex_lock(&ftrace_lock);
3458 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3460 ftrace_ops_update_code(ops);
3462 mutex_unlock(&ftrace_lock);
3465 mutex_unlock(&ops->regex_lock);
3467 free_ftrace_hash(hash);
3472 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
3473 int reset, int enable)
3475 return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
3479 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
3480 * @ops - the ops to set the filter with
3481 * @ip - the address to add to or remove from the filter.
3482 * @remove - non zero to remove the ip from the filter
3483 * @reset - non zero to reset all filters before applying this filter.
3485 * Filters denote which functions should be enabled when tracing is enabled
3486 * If @ip is NULL, it failes to update filter.
3488 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
3489 int remove, int reset)
3491 ftrace_ops_init(ops);
3492 return ftrace_set_addr(ops, ip, remove, reset, 1);
3494 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
3497 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
3498 int reset, int enable)
3500 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
3504 * ftrace_set_filter - set a function to filter on in ftrace
3505 * @ops - the ops to set the filter with
3506 * @buf - the string that holds the function filter text.
3507 * @len - the length of the string.
3508 * @reset - non zero to reset all filters before applying this filter.
3510 * Filters denote which functions should be enabled when tracing is enabled.
3511 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3513 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
3516 ftrace_ops_init(ops);
3517 return ftrace_set_regex(ops, buf, len, reset, 1);
3519 EXPORT_SYMBOL_GPL(ftrace_set_filter);
3522 * ftrace_set_notrace - set a function to not trace in ftrace
3523 * @ops - the ops to set the notrace filter with
3524 * @buf - the string that holds the function notrace text.
3525 * @len - the length of the string.
3526 * @reset - non zero to reset all filters before applying this filter.
3528 * Notrace Filters denote which functions should not be enabled when tracing
3529 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3532 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
3535 ftrace_ops_init(ops);
3536 return ftrace_set_regex(ops, buf, len, reset, 0);
3538 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
3540 * ftrace_set_filter - set a function to filter on in ftrace
3541 * @ops - the ops to set the filter with
3542 * @buf - the string that holds the function filter text.
3543 * @len - the length of the string.
3544 * @reset - non zero to reset all filters before applying this filter.
3546 * Filters denote which functions should be enabled when tracing is enabled.
3547 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3549 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
3551 ftrace_set_regex(&global_ops, buf, len, reset, 1);
3553 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
3556 * ftrace_set_notrace - set a function to not trace in ftrace
3557 * @ops - the ops to set the notrace filter with
3558 * @buf - the string that holds the function notrace text.
3559 * @len - the length of the string.
3560 * @reset - non zero to reset all filters before applying this filter.
3562 * Notrace Filters denote which functions should not be enabled when tracing
3563 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3566 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
3568 ftrace_set_regex(&global_ops, buf, len, reset, 0);
3570 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
3573 * command line interface to allow users to set filters on boot up.
3575 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
3576 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
3577 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
3579 /* Used by function selftest to not test if filter is set */
3580 bool ftrace_filter_param __initdata;
3582 static int __init set_ftrace_notrace(char *str)
3584 ftrace_filter_param = true;
3585 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
3588 __setup("ftrace_notrace=", set_ftrace_notrace);
3590 static int __init set_ftrace_filter(char *str)
3592 ftrace_filter_param = true;
3593 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
3596 __setup("ftrace_filter=", set_ftrace_filter);
3598 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3599 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
3600 static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer);
3602 static int __init set_graph_function(char *str)
3604 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
3607 __setup("ftrace_graph_filter=", set_graph_function);
3609 static void __init set_ftrace_early_graph(char *buf)
3615 func = strsep(&buf, ",");
3616 /* we allow only one expression at a time */
3617 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3618 FTRACE_GRAPH_MAX_FUNCS, func);
3620 printk(KERN_DEBUG "ftrace: function %s not "
3621 "traceable\n", func);
3624 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3627 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
3631 ftrace_ops_init(ops);
3634 func = strsep(&buf, ",");
3635 ftrace_set_regex(ops, func, strlen(func), 0, enable);
3639 static void __init set_ftrace_early_filters(void)
3641 if (ftrace_filter_buf[0])
3642 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
3643 if (ftrace_notrace_buf[0])
3644 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
3645 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3646 if (ftrace_graph_buf[0])
3647 set_ftrace_early_graph(ftrace_graph_buf);
3648 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3651 int ftrace_regex_release(struct inode *inode, struct file *file)
3653 struct seq_file *m = (struct seq_file *)file->private_data;
3654 struct ftrace_iterator *iter;
3655 struct ftrace_hash **orig_hash;
3656 struct trace_parser *parser;
3660 if (file->f_mode & FMODE_READ) {
3662 seq_release(inode, file);
3664 iter = file->private_data;
3666 parser = &iter->parser;
3667 if (trace_parser_loaded(parser)) {
3668 parser->buffer[parser->idx] = 0;
3669 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
3672 trace_parser_put(parser);
3674 mutex_lock(&iter->ops->regex_lock);
3676 if (file->f_mode & FMODE_WRITE) {
3677 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
3680 orig_hash = &iter->ops->filter_hash;
3682 orig_hash = &iter->ops->notrace_hash;
3684 mutex_lock(&ftrace_lock);
3685 ret = ftrace_hash_move(iter->ops, filter_hash,
3686 orig_hash, iter->hash);
3688 ftrace_ops_update_code(iter->ops);
3690 mutex_unlock(&ftrace_lock);
3693 mutex_unlock(&iter->ops->regex_lock);
3694 free_ftrace_hash(iter->hash);
3700 static const struct file_operations ftrace_avail_fops = {
3701 .open = ftrace_avail_open,
3703 .llseek = seq_lseek,
3704 .release = seq_release_private,
3707 static const struct file_operations ftrace_enabled_fops = {
3708 .open = ftrace_enabled_open,
3710 .llseek = seq_lseek,
3711 .release = seq_release_private,
3714 static const struct file_operations ftrace_filter_fops = {
3715 .open = ftrace_filter_open,
3717 .write = ftrace_filter_write,
3718 .llseek = tracing_lseek,
3719 .release = ftrace_regex_release,
3722 static const struct file_operations ftrace_notrace_fops = {
3723 .open = ftrace_notrace_open,
3725 .write = ftrace_notrace_write,
3726 .llseek = tracing_lseek,
3727 .release = ftrace_regex_release,
3730 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3732 static DEFINE_MUTEX(graph_lock);
3734 int ftrace_graph_count;
3735 int ftrace_graph_notrace_count;
3736 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
3737 unsigned long ftrace_graph_notrace_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
3739 struct ftrace_graph_data {
3740 unsigned long *table;
3743 const struct seq_operations *seq_ops;
3747 __g_next(struct seq_file *m, loff_t *pos)
3749 struct ftrace_graph_data *fgd = m->private;
3751 if (*pos >= *fgd->count)
3753 return &fgd->table[*pos];
3757 g_next(struct seq_file *m, void *v, loff_t *pos)
3760 return __g_next(m, pos);
3763 static void *g_start(struct seq_file *m, loff_t *pos)
3765 struct ftrace_graph_data *fgd = m->private;
3767 mutex_lock(&graph_lock);
3769 /* Nothing, tell g_show to print all functions are enabled */
3770 if (!*fgd->count && !*pos)
3773 return __g_next(m, pos);
3776 static void g_stop(struct seq_file *m, void *p)
3778 mutex_unlock(&graph_lock);
3781 static int g_show(struct seq_file *m, void *v)
3783 unsigned long *ptr = v;
3788 if (ptr == (unsigned long *)1) {
3789 seq_printf(m, "#### all functions enabled ####\n");
3793 seq_printf(m, "%ps\n", (void *)*ptr);
3798 static const struct seq_operations ftrace_graph_seq_ops = {
3806 __ftrace_graph_open(struct inode *inode, struct file *file,
3807 struct ftrace_graph_data *fgd)
3811 mutex_lock(&graph_lock);
3812 if ((file->f_mode & FMODE_WRITE) &&
3813 (file->f_flags & O_TRUNC)) {
3815 memset(fgd->table, 0, fgd->size * sizeof(*fgd->table));
3817 mutex_unlock(&graph_lock);
3819 if (file->f_mode & FMODE_READ) {
3820 ret = seq_open(file, fgd->seq_ops);
3822 struct seq_file *m = file->private_data;
3826 file->private_data = fgd;
3832 ftrace_graph_open(struct inode *inode, struct file *file)
3834 struct ftrace_graph_data *fgd;
3836 if (unlikely(ftrace_disabled))
3839 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
3843 fgd->table = ftrace_graph_funcs;
3844 fgd->size = FTRACE_GRAPH_MAX_FUNCS;
3845 fgd->count = &ftrace_graph_count;
3846 fgd->seq_ops = &ftrace_graph_seq_ops;
3848 return __ftrace_graph_open(inode, file, fgd);
3852 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
3854 struct ftrace_graph_data *fgd;
3856 if (unlikely(ftrace_disabled))
3859 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
3863 fgd->table = ftrace_graph_notrace_funcs;
3864 fgd->size = FTRACE_GRAPH_MAX_FUNCS;
3865 fgd->count = &ftrace_graph_notrace_count;
3866 fgd->seq_ops = &ftrace_graph_seq_ops;
3868 return __ftrace_graph_open(inode, file, fgd);
3872 ftrace_graph_release(struct inode *inode, struct file *file)
3874 if (file->f_mode & FMODE_READ) {
3875 struct seq_file *m = file->private_data;
3878 seq_release(inode, file);
3880 kfree(file->private_data);
3887 ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer)
3889 struct dyn_ftrace *rec;
3890 struct ftrace_page *pg;
3899 type = filter_parse_regex(buffer, strlen(buffer), &search, ¬);
3900 if (!not && *idx >= size)
3903 search_len = strlen(search);
3905 mutex_lock(&ftrace_lock);
3907 if (unlikely(ftrace_disabled)) {
3908 mutex_unlock(&ftrace_lock);
3912 do_for_each_ftrace_rec(pg, rec) {
3914 if (ftrace_match_record(rec, NULL, search, search_len, type)) {
3915 /* if it is in the array */
3917 for (i = 0; i < *idx; i++) {
3918 if (array[i] == rec->ip) {
3927 array[(*idx)++] = rec->ip;
3933 array[i] = array[--(*idx)];
3939 } while_for_each_ftrace_rec();
3941 mutex_unlock(&ftrace_lock);
3950 ftrace_graph_write(struct file *file, const char __user *ubuf,
3951 size_t cnt, loff_t *ppos)
3953 struct trace_parser parser;
3954 ssize_t read, ret = 0;
3955 struct ftrace_graph_data *fgd = file->private_data;
3960 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX))
3963 read = trace_get_user(&parser, ubuf, cnt, ppos);
3965 if (read >= 0 && trace_parser_loaded((&parser))) {
3966 parser.buffer[parser.idx] = 0;
3968 mutex_lock(&graph_lock);
3970 /* we allow only one expression at a time */
3971 ret = ftrace_set_func(fgd->table, fgd->count, fgd->size,
3974 mutex_unlock(&graph_lock);
3980 trace_parser_put(&parser);
3985 static const struct file_operations ftrace_graph_fops = {
3986 .open = ftrace_graph_open,
3988 .write = ftrace_graph_write,
3989 .llseek = tracing_lseek,
3990 .release = ftrace_graph_release,
3993 static const struct file_operations ftrace_graph_notrace_fops = {
3994 .open = ftrace_graph_notrace_open,
3996 .write = ftrace_graph_write,
3997 .llseek = tracing_lseek,
3998 .release = ftrace_graph_release,
4000 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4002 void ftrace_create_filter_files(struct ftrace_ops *ops,
4003 struct dentry *parent)
4006 trace_create_file("set_ftrace_filter", 0644, parent,
4007 ops, &ftrace_filter_fops);
4009 trace_create_file("set_ftrace_notrace", 0644, parent,
4010 ops, &ftrace_notrace_fops);
4014 * The name "destroy_filter_files" is really a misnomer. Although
4015 * in the future, it may actualy delete the files, but this is
4016 * really intended to make sure the ops passed in are disabled
4017 * and that when this function returns, the caller is free to
4020 * The "destroy" name is only to match the "create" name that this
4021 * should be paired with.
4023 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
4025 mutex_lock(&ftrace_lock);
4026 if (ops->flags & FTRACE_OPS_FL_ENABLED)
4027 ftrace_shutdown(ops, 0);
4028 ops->flags |= FTRACE_OPS_FL_DELETED;
4029 mutex_unlock(&ftrace_lock);
4032 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
4035 trace_create_file("available_filter_functions", 0444,
4036 d_tracer, NULL, &ftrace_avail_fops);
4038 trace_create_file("enabled_functions", 0444,
4039 d_tracer, NULL, &ftrace_enabled_fops);
4041 ftrace_create_filter_files(&global_ops, d_tracer);
4043 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4044 trace_create_file("set_graph_function", 0444, d_tracer,
4046 &ftrace_graph_fops);
4047 trace_create_file("set_graph_notrace", 0444, d_tracer,
4049 &ftrace_graph_notrace_fops);
4050 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4055 static int ftrace_cmp_ips(const void *a, const void *b)
4057 const unsigned long *ipa = a;
4058 const unsigned long *ipb = b;
4067 static void ftrace_swap_ips(void *a, void *b, int size)
4069 unsigned long *ipa = a;
4070 unsigned long *ipb = b;
4078 static int ftrace_process_locs(struct module *mod,
4079 unsigned long *start,
4082 struct ftrace_page *start_pg;
4083 struct ftrace_page *pg;
4084 struct dyn_ftrace *rec;
4085 unsigned long count;
4088 unsigned long flags = 0; /* Shut up gcc */
4091 count = end - start;
4096 sort(start, count, sizeof(*start),
4097 ftrace_cmp_ips, ftrace_swap_ips);
4099 start_pg = ftrace_allocate_pages(count);
4103 mutex_lock(&ftrace_lock);
4106 * Core and each module needs their own pages, as
4107 * modules will free them when they are removed.
4108 * Force a new page to be allocated for modules.
4111 WARN_ON(ftrace_pages || ftrace_pages_start);
4112 /* First initialization */
4113 ftrace_pages = ftrace_pages_start = start_pg;
4118 if (WARN_ON(ftrace_pages->next)) {
4119 /* Hmm, we have free pages? */
4120 while (ftrace_pages->next)
4121 ftrace_pages = ftrace_pages->next;
4124 ftrace_pages->next = start_pg;
4130 addr = ftrace_call_adjust(*p++);
4132 * Some architecture linkers will pad between
4133 * the different mcount_loc sections of different
4134 * object files to satisfy alignments.
4135 * Skip any NULL pointers.
4140 if (pg->index == pg->size) {
4141 /* We should have allocated enough */
4142 if (WARN_ON(!pg->next))
4147 rec = &pg->records[pg->index++];
4151 /* We should have used all pages */
4154 /* Assign the last page to ftrace_pages */
4158 * We only need to disable interrupts on start up
4159 * because we are modifying code that an interrupt
4160 * may execute, and the modification is not atomic.
4161 * But for modules, nothing runs the code we modify
4162 * until we are finished with it, and there's no
4163 * reason to cause large interrupt latencies while we do it.
4166 local_irq_save(flags);
4167 ftrace_update_code(mod, start_pg);
4169 local_irq_restore(flags);
4172 mutex_unlock(&ftrace_lock);
4177 #ifdef CONFIG_MODULES
4179 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
4181 void ftrace_release_mod(struct module *mod)
4183 struct dyn_ftrace *rec;
4184 struct ftrace_page **last_pg;
4185 struct ftrace_page *pg;
4188 mutex_lock(&ftrace_lock);
4190 if (ftrace_disabled)
4194 * Each module has its own ftrace_pages, remove
4195 * them from the list.
4197 last_pg = &ftrace_pages_start;
4198 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
4199 rec = &pg->records[0];
4200 if (within_module_core(rec->ip, mod)) {
4202 * As core pages are first, the first
4203 * page should never be a module page.
4205 if (WARN_ON(pg == ftrace_pages_start))
4208 /* Check if we are deleting the last page */
4209 if (pg == ftrace_pages)
4210 ftrace_pages = next_to_ftrace_page(last_pg);
4212 *last_pg = pg->next;
4213 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
4214 free_pages((unsigned long)pg->records, order);
4217 last_pg = &pg->next;
4220 mutex_unlock(&ftrace_lock);
4223 static void ftrace_init_module(struct module *mod,
4224 unsigned long *start, unsigned long *end)
4226 if (ftrace_disabled || start == end)
4228 ftrace_process_locs(mod, start, end);
4231 static int ftrace_module_notify_enter(struct notifier_block *self,
4232 unsigned long val, void *data)
4234 struct module *mod = data;
4236 if (val == MODULE_STATE_COMING)
4237 ftrace_init_module(mod, mod->ftrace_callsites,
4238 mod->ftrace_callsites +
4239 mod->num_ftrace_callsites);
4243 static int ftrace_module_notify_exit(struct notifier_block *self,
4244 unsigned long val, void *data)
4246 struct module *mod = data;
4248 if (val == MODULE_STATE_GOING)
4249 ftrace_release_mod(mod);
4254 static int ftrace_module_notify_enter(struct notifier_block *self,
4255 unsigned long val, void *data)
4259 static int ftrace_module_notify_exit(struct notifier_block *self,
4260 unsigned long val, void *data)
4264 #endif /* CONFIG_MODULES */
4266 struct notifier_block ftrace_module_enter_nb = {
4267 .notifier_call = ftrace_module_notify_enter,
4268 .priority = INT_MAX, /* Run before anything that can use kprobes */
4271 struct notifier_block ftrace_module_exit_nb = {
4272 .notifier_call = ftrace_module_notify_exit,
4273 .priority = INT_MIN, /* Run after anything that can remove kprobes */
4276 void __init ftrace_init(void)
4278 extern unsigned long __start_mcount_loc[];
4279 extern unsigned long __stop_mcount_loc[];
4280 unsigned long count, flags;
4283 local_irq_save(flags);
4284 ret = ftrace_dyn_arch_init();
4285 local_irq_restore(flags);
4289 count = __stop_mcount_loc - __start_mcount_loc;
4291 pr_info("ftrace: No functions to be traced?\n");
4295 pr_info("ftrace: allocating %ld entries in %ld pages\n",
4296 count, count / ENTRIES_PER_PAGE + 1);
4298 last_ftrace_enabled = ftrace_enabled = 1;
4300 ret = ftrace_process_locs(NULL,
4304 ret = register_module_notifier(&ftrace_module_enter_nb);
4306 pr_warning("Failed to register trace ftrace module enter notifier\n");
4308 ret = register_module_notifier(&ftrace_module_exit_nb);
4310 pr_warning("Failed to register trace ftrace module exit notifier\n");
4312 set_ftrace_early_filters();
4316 ftrace_disabled = 1;
4321 static struct ftrace_ops global_ops = {
4322 .func = ftrace_stub,
4323 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
4324 INIT_REGEX_LOCK(global_ops)
4327 static int __init ftrace_nodyn_init(void)
4332 core_initcall(ftrace_nodyn_init);
4334 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
4335 static inline void ftrace_startup_enable(int command) { }
4336 /* Keep as macros so we do not need to define the commands */
4337 # define ftrace_startup(ops, command) \
4339 int ___ret = __register_ftrace_function(ops); \
4341 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
4344 # define ftrace_shutdown(ops, command) \
4346 int ___ret = __unregister_ftrace_function(ops); \
4348 (ops)->flags &= ~FTRACE_OPS_FL_ENABLED; \
4352 # define ftrace_startup_sysctl() do { } while (0)
4353 # define ftrace_shutdown_sysctl() do { } while (0)
4356 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
4361 #endif /* CONFIG_DYNAMIC_FTRACE */
4363 __init void ftrace_init_global_array_ops(struct trace_array *tr)
4365 tr->ops = &global_ops;
4366 tr->ops->private = tr;
4369 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
4371 /* If we filter on pids, update to use the pid function */
4372 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
4373 if (WARN_ON(tr->ops->func != ftrace_stub))
4374 printk("ftrace ops had %pS for function\n",
4376 /* Only the top level instance does pid tracing */
4377 if (!list_empty(&ftrace_pids)) {
4378 set_ftrace_pid_function(func);
4379 func = ftrace_pid_func;
4382 tr->ops->func = func;
4383 tr->ops->private = tr;
4386 void ftrace_reset_array_ops(struct trace_array *tr)
4388 tr->ops->func = ftrace_stub;
4392 ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
4393 struct ftrace_ops *op, struct pt_regs *regs)
4395 if (unlikely(trace_recursion_test(TRACE_CONTROL_BIT)))
4399 * Some of the ops may be dynamically allocated,
4400 * they must be freed after a synchronize_sched().
4402 preempt_disable_notrace();
4403 trace_recursion_set(TRACE_CONTROL_BIT);
4406 * Control funcs (perf) uses RCU. Only trace if
4407 * RCU is currently active.
4409 if (!rcu_is_watching())
4412 do_for_each_ftrace_op(op, ftrace_control_list) {
4413 if (!(op->flags & FTRACE_OPS_FL_STUB) &&
4414 !ftrace_function_local_disabled(op) &&
4415 ftrace_ops_test(op, ip, regs))
4416 op->func(ip, parent_ip, op, regs);
4417 } while_for_each_ftrace_op(op);
4419 trace_recursion_clear(TRACE_CONTROL_BIT);
4420 preempt_enable_notrace();
4423 static struct ftrace_ops control_ops = {
4424 .func = ftrace_ops_control_func,
4425 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
4426 INIT_REGEX_LOCK(control_ops)
4430 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
4431 struct ftrace_ops *ignored, struct pt_regs *regs)
4433 struct ftrace_ops *op;
4436 if (function_trace_stop)
4439 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
4444 * Some of the ops may be dynamically allocated,
4445 * they must be freed after a synchronize_sched().
4447 preempt_disable_notrace();
4448 do_for_each_ftrace_op(op, ftrace_ops_list) {
4449 if (ftrace_ops_test(op, ip, regs)) {
4450 if (WARN_ON(!op->func)) {
4451 function_trace_stop = 1;
4452 printk("op=%p %pS\n", op, op);
4455 op->func(ip, parent_ip, op, regs);
4457 } while_for_each_ftrace_op(op);
4459 preempt_enable_notrace();
4460 trace_clear_recursion(bit);
4464 * Some archs only support passing ip and parent_ip. Even though
4465 * the list function ignores the op parameter, we do not want any
4466 * C side effects, where a function is called without the caller
4467 * sending a third parameter.
4468 * Archs are to support both the regs and ftrace_ops at the same time.
4469 * If they support ftrace_ops, it is assumed they support regs.
4470 * If call backs want to use regs, they must either check for regs
4471 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
4472 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
4473 * An architecture can pass partial regs with ftrace_ops and still
4474 * set the ARCH_SUPPORT_FTARCE_OPS.
4476 #if ARCH_SUPPORTS_FTRACE_OPS
4477 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
4478 struct ftrace_ops *op, struct pt_regs *regs)
4480 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
4483 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
4485 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
4489 static void clear_ftrace_swapper(void)
4491 struct task_struct *p;
4495 for_each_online_cpu(cpu) {
4497 clear_tsk_trace_trace(p);
4502 static void set_ftrace_swapper(void)
4504 struct task_struct *p;
4508 for_each_online_cpu(cpu) {
4510 set_tsk_trace_trace(p);
4515 static void clear_ftrace_pid(struct pid *pid)
4517 struct task_struct *p;
4520 do_each_pid_task(pid, PIDTYPE_PID, p) {
4521 clear_tsk_trace_trace(p);
4522 } while_each_pid_task(pid, PIDTYPE_PID, p);
4528 static void set_ftrace_pid(struct pid *pid)
4530 struct task_struct *p;
4533 do_each_pid_task(pid, PIDTYPE_PID, p) {
4534 set_tsk_trace_trace(p);
4535 } while_each_pid_task(pid, PIDTYPE_PID, p);
4539 static void clear_ftrace_pid_task(struct pid *pid)
4541 if (pid == ftrace_swapper_pid)
4542 clear_ftrace_swapper();
4544 clear_ftrace_pid(pid);
4547 static void set_ftrace_pid_task(struct pid *pid)
4549 if (pid == ftrace_swapper_pid)
4550 set_ftrace_swapper();
4552 set_ftrace_pid(pid);
4555 static int ftrace_pid_add(int p)
4558 struct ftrace_pid *fpid;
4561 mutex_lock(&ftrace_lock);
4564 pid = ftrace_swapper_pid;
4566 pid = find_get_pid(p);
4573 list_for_each_entry(fpid, &ftrace_pids, list)
4574 if (fpid->pid == pid)
4579 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
4583 list_add(&fpid->list, &ftrace_pids);
4586 set_ftrace_pid_task(pid);
4588 ftrace_update_pid_func();
4589 ftrace_startup_enable(0);
4591 mutex_unlock(&ftrace_lock);
4595 if (pid != ftrace_swapper_pid)
4599 mutex_unlock(&ftrace_lock);
4603 static void ftrace_pid_reset(void)
4605 struct ftrace_pid *fpid, *safe;
4607 mutex_lock(&ftrace_lock);
4608 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
4609 struct pid *pid = fpid->pid;
4611 clear_ftrace_pid_task(pid);
4613 list_del(&fpid->list);
4617 ftrace_update_pid_func();
4618 ftrace_startup_enable(0);
4620 mutex_unlock(&ftrace_lock);
4623 static void *fpid_start(struct seq_file *m, loff_t *pos)
4625 mutex_lock(&ftrace_lock);
4627 if (list_empty(&ftrace_pids) && (!*pos))
4630 return seq_list_start(&ftrace_pids, *pos);
4633 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
4638 return seq_list_next(v, &ftrace_pids, pos);
4641 static void fpid_stop(struct seq_file *m, void *p)
4643 mutex_unlock(&ftrace_lock);
4646 static int fpid_show(struct seq_file *m, void *v)
4648 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
4650 if (v == (void *)1) {
4651 seq_printf(m, "no pid\n");
4655 if (fpid->pid == ftrace_swapper_pid)
4656 seq_printf(m, "swapper tasks\n");
4658 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
4663 static const struct seq_operations ftrace_pid_sops = {
4664 .start = fpid_start,
4671 ftrace_pid_open(struct inode *inode, struct file *file)
4675 if ((file->f_mode & FMODE_WRITE) &&
4676 (file->f_flags & O_TRUNC))
4679 if (file->f_mode & FMODE_READ)
4680 ret = seq_open(file, &ftrace_pid_sops);
4686 ftrace_pid_write(struct file *filp, const char __user *ubuf,
4687 size_t cnt, loff_t *ppos)
4693 if (cnt >= sizeof(buf))
4696 if (copy_from_user(&buf, ubuf, cnt))
4702 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
4703 * to clean the filter quietly.
4705 tmp = strstrip(buf);
4706 if (strlen(tmp) == 0)
4709 ret = kstrtol(tmp, 10, &val);
4713 ret = ftrace_pid_add(val);
4715 return ret ? ret : cnt;
4719 ftrace_pid_release(struct inode *inode, struct file *file)
4721 if (file->f_mode & FMODE_READ)
4722 seq_release(inode, file);
4727 static const struct file_operations ftrace_pid_fops = {
4728 .open = ftrace_pid_open,
4729 .write = ftrace_pid_write,
4731 .llseek = tracing_lseek,
4732 .release = ftrace_pid_release,
4735 static __init int ftrace_init_debugfs(void)
4737 struct dentry *d_tracer;
4739 d_tracer = tracing_init_dentry();
4743 ftrace_init_dyn_debugfs(d_tracer);
4745 trace_create_file("set_ftrace_pid", 0644, d_tracer,
4746 NULL, &ftrace_pid_fops);
4748 ftrace_profile_debugfs(d_tracer);
4752 fs_initcall(ftrace_init_debugfs);
4755 * ftrace_kill - kill ftrace
4757 * This function should be used by panic code. It stops ftrace
4758 * but in a not so nice way. If you need to simply kill ftrace
4759 * from a non-atomic section, use ftrace_kill.
4761 void ftrace_kill(void)
4763 ftrace_disabled = 1;
4765 clear_ftrace_function();
4769 * Test if ftrace is dead or not.
4771 int ftrace_is_dead(void)
4773 return ftrace_disabled;
4777 * register_ftrace_function - register a function for profiling
4778 * @ops - ops structure that holds the function for profiling.
4780 * Register a function to be called by all functions in the
4783 * Note: @ops->func and all the functions it calls must be labeled
4784 * with "notrace", otherwise it will go into a
4787 int register_ftrace_function(struct ftrace_ops *ops)
4791 ftrace_ops_init(ops);
4793 mutex_lock(&ftrace_lock);
4795 ret = ftrace_startup(ops, 0);
4797 mutex_unlock(&ftrace_lock);
4801 EXPORT_SYMBOL_GPL(register_ftrace_function);
4804 * unregister_ftrace_function - unregister a function for profiling.
4805 * @ops - ops structure that holds the function to unregister
4807 * Unregister a function that was added to be called by ftrace profiling.
4809 int unregister_ftrace_function(struct ftrace_ops *ops)
4813 mutex_lock(&ftrace_lock);
4814 ret = ftrace_shutdown(ops, 0);
4815 mutex_unlock(&ftrace_lock);
4819 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
4822 ftrace_enable_sysctl(struct ctl_table *table, int write,
4823 void __user *buffer, size_t *lenp,
4828 mutex_lock(&ftrace_lock);
4830 if (unlikely(ftrace_disabled))
4833 ret = proc_dointvec(table, write, buffer, lenp, ppos);
4835 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
4838 last_ftrace_enabled = !!ftrace_enabled;
4840 if (ftrace_enabled) {
4842 ftrace_startup_sysctl();
4844 /* we are starting ftrace again */
4845 if (ftrace_ops_list != &ftrace_list_end)
4846 update_ftrace_function();
4849 /* stopping ftrace calls (just send to ftrace_stub) */
4850 ftrace_trace_function = ftrace_stub;
4852 ftrace_shutdown_sysctl();
4856 mutex_unlock(&ftrace_lock);
4860 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4862 static int ftrace_graph_active;
4863 static struct notifier_block ftrace_suspend_notifier;
4865 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
4870 /* The callbacks that hook a function */
4871 trace_func_graph_ret_t ftrace_graph_return =
4872 (trace_func_graph_ret_t)ftrace_stub;
4873 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
4874 static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
4876 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
4877 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
4881 unsigned long flags;
4882 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
4883 struct task_struct *g, *t;
4885 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
4886 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
4887 * sizeof(struct ftrace_ret_stack),
4889 if (!ret_stack_list[i]) {
4897 read_lock_irqsave(&tasklist_lock, flags);
4898 do_each_thread(g, t) {
4904 if (t->ret_stack == NULL) {
4905 atomic_set(&t->tracing_graph_pause, 0);
4906 atomic_set(&t->trace_overrun, 0);
4907 t->curr_ret_stack = -1;
4908 /* Make sure the tasks see the -1 first: */
4910 t->ret_stack = ret_stack_list[start++];
4912 } while_each_thread(g, t);
4915 read_unlock_irqrestore(&tasklist_lock, flags);
4917 for (i = start; i < end; i++)
4918 kfree(ret_stack_list[i]);
4923 ftrace_graph_probe_sched_switch(void *ignore,
4924 struct task_struct *prev, struct task_struct *next)
4926 unsigned long long timestamp;
4930 * Does the user want to count the time a function was asleep.
4931 * If so, do not update the time stamps.
4933 if (trace_flags & TRACE_ITER_SLEEP_TIME)
4936 timestamp = trace_clock_local();
4938 prev->ftrace_timestamp = timestamp;
4940 /* only process tasks that we timestamped */
4941 if (!next->ftrace_timestamp)
4945 * Update all the counters in next to make up for the
4946 * time next was sleeping.
4948 timestamp -= next->ftrace_timestamp;
4950 for (index = next->curr_ret_stack; index >= 0; index--)
4951 next->ret_stack[index].calltime += timestamp;
4954 /* Allocate a return stack for each task */
4955 static int start_graph_tracing(void)
4957 struct ftrace_ret_stack **ret_stack_list;
4960 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
4961 sizeof(struct ftrace_ret_stack *),
4964 if (!ret_stack_list)
4967 /* The cpu_boot init_task->ret_stack will never be freed */
4968 for_each_online_cpu(cpu) {
4969 if (!idle_task(cpu)->ret_stack)
4970 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
4974 ret = alloc_retstack_tasklist(ret_stack_list);
4975 } while (ret == -EAGAIN);
4978 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4980 pr_info("ftrace_graph: Couldn't activate tracepoint"
4981 " probe to kernel_sched_switch\n");
4984 kfree(ret_stack_list);
4989 * Hibernation protection.
4990 * The state of the current task is too much unstable during
4991 * suspend/restore to disk. We want to protect against that.
4994 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
4998 case PM_HIBERNATION_PREPARE:
4999 pause_graph_tracing();
5002 case PM_POST_HIBERNATION:
5003 unpause_graph_tracing();
5009 /* Just a place holder for function graph */
5010 static struct ftrace_ops fgraph_ops __read_mostly = {
5011 .func = ftrace_stub,
5012 .flags = FTRACE_OPS_FL_STUB | FTRACE_OPS_FL_RECURSION_SAFE,
5015 static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
5017 if (!ftrace_ops_test(&global_ops, trace->func, NULL))
5019 return __ftrace_graph_entry(trace);
5023 * The function graph tracer should only trace the functions defined
5024 * by set_ftrace_filter and set_ftrace_notrace. If another function
5025 * tracer ops is registered, the graph tracer requires testing the
5026 * function against the global ops, and not just trace any function
5027 * that any ftrace_ops registered.
5029 static void update_function_graph_func(void)
5031 if (ftrace_ops_list == &ftrace_list_end ||
5032 (ftrace_ops_list == &global_ops &&
5033 global_ops.next == &ftrace_list_end))
5034 ftrace_graph_entry = __ftrace_graph_entry;
5036 ftrace_graph_entry = ftrace_graph_entry_test;
5039 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
5040 trace_func_graph_ent_t entryfunc)
5044 mutex_lock(&ftrace_lock);
5046 /* we currently allow only one tracer registered at a time */
5047 if (ftrace_graph_active) {
5052 ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
5053 register_pm_notifier(&ftrace_suspend_notifier);
5055 ftrace_graph_active++;
5056 ret = start_graph_tracing();
5058 ftrace_graph_active--;
5062 ftrace_graph_return = retfunc;
5065 * Update the indirect function to the entryfunc, and the
5066 * function that gets called to the entry_test first. Then
5067 * call the update fgraph entry function to determine if
5068 * the entryfunc should be called directly or not.
5070 __ftrace_graph_entry = entryfunc;
5071 ftrace_graph_entry = ftrace_graph_entry_test;
5072 update_function_graph_func();
5074 ret = ftrace_startup(&fgraph_ops, FTRACE_START_FUNC_RET);
5077 mutex_unlock(&ftrace_lock);
5081 void unregister_ftrace_graph(void)
5083 mutex_lock(&ftrace_lock);
5085 if (unlikely(!ftrace_graph_active))
5088 ftrace_graph_active--;
5089 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
5090 ftrace_graph_entry = ftrace_graph_entry_stub;
5091 __ftrace_graph_entry = ftrace_graph_entry_stub;
5092 ftrace_shutdown(&fgraph_ops, FTRACE_STOP_FUNC_RET);
5093 unregister_pm_notifier(&ftrace_suspend_notifier);
5094 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5097 mutex_unlock(&ftrace_lock);
5100 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
5103 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
5105 atomic_set(&t->tracing_graph_pause, 0);
5106 atomic_set(&t->trace_overrun, 0);
5107 t->ftrace_timestamp = 0;
5108 /* make curr_ret_stack visible before we add the ret_stack */
5110 t->ret_stack = ret_stack;
5114 * Allocate a return stack for the idle task. May be the first
5115 * time through, or it may be done by CPU hotplug online.
5117 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
5119 t->curr_ret_stack = -1;
5121 * The idle task has no parent, it either has its own
5122 * stack or no stack at all.
5125 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
5127 if (ftrace_graph_active) {
5128 struct ftrace_ret_stack *ret_stack;
5130 ret_stack = per_cpu(idle_ret_stack, cpu);
5132 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
5133 * sizeof(struct ftrace_ret_stack),
5137 per_cpu(idle_ret_stack, cpu) = ret_stack;
5139 graph_init_task(t, ret_stack);
5143 /* Allocate a return stack for newly created task */
5144 void ftrace_graph_init_task(struct task_struct *t)
5146 /* Make sure we do not use the parent ret_stack */
5147 t->ret_stack = NULL;
5148 t->curr_ret_stack = -1;
5150 if (ftrace_graph_active) {
5151 struct ftrace_ret_stack *ret_stack;
5153 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
5154 * sizeof(struct ftrace_ret_stack),
5158 graph_init_task(t, ret_stack);
5162 void ftrace_graph_exit_task(struct task_struct *t)
5164 struct ftrace_ret_stack *ret_stack = t->ret_stack;
5166 t->ret_stack = NULL;
5167 /* NULL must become visible to IRQs before we free it: */
5173 void ftrace_graph_stop(void)