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/sched/task.h>
19 #include <linux/kallsyms.h>
20 #include <linux/seq_file.h>
21 #include <linux/suspend.h>
22 #include <linux/tracefs.h>
23 #include <linux/hardirq.h>
24 #include <linux/kthread.h>
25 #include <linux/uaccess.h>
26 #include <linux/bsearch.h>
27 #include <linux/module.h>
28 #include <linux/ftrace.h>
29 #include <linux/sysctl.h>
30 #include <linux/slab.h>
31 #include <linux/ctype.h>
32 #include <linux/sort.h>
33 #include <linux/list.h>
34 #include <linux/hash.h>
35 #include <linux/rcupdate.h>
36 #include <linux/kprobes.h>
38 #include <trace/events/sched.h>
40 #include <asm/sections.h>
41 #include <asm/setup.h>
43 #include "trace_output.h"
44 #include "trace_stat.h"
46 #define FTRACE_WARN_ON(cond) \
54 #define FTRACE_WARN_ON_ONCE(cond) \
57 if (WARN_ON_ONCE(___r)) \
62 /* hash bits for specific function selection */
63 #define FTRACE_HASH_BITS 7
64 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
65 #define FTRACE_HASH_DEFAULT_BITS 10
66 #define FTRACE_HASH_MAX_BITS 12
68 #ifdef CONFIG_DYNAMIC_FTRACE
69 #define INIT_OPS_HASH(opsname) \
70 .func_hash = &opsname.local_hash, \
71 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
72 #define ASSIGN_OPS_HASH(opsname, val) \
74 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
76 #define INIT_OPS_HASH(opsname)
77 #define ASSIGN_OPS_HASH(opsname, val)
80 static struct ftrace_ops ftrace_list_end __read_mostly = {
82 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
83 INIT_OPS_HASH(ftrace_list_end)
86 /* ftrace_enabled is a method to turn ftrace on or off */
87 int ftrace_enabled __read_mostly;
88 static int last_ftrace_enabled;
90 /* Current function tracing op */
91 struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
92 /* What to set function_trace_op to */
93 static struct ftrace_ops *set_function_trace_op;
95 static bool ftrace_pids_enabled(struct ftrace_ops *ops)
97 struct trace_array *tr;
99 if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
104 return tr->function_pids != NULL;
107 static void ftrace_update_trampoline(struct ftrace_ops *ops);
110 * ftrace_disabled is set when an anomaly is discovered.
111 * ftrace_disabled is much stronger than ftrace_enabled.
113 static int ftrace_disabled __read_mostly;
115 static DEFINE_MUTEX(ftrace_lock);
117 static struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
118 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
119 static struct ftrace_ops global_ops;
121 #if ARCH_SUPPORTS_FTRACE_OPS
122 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
123 struct ftrace_ops *op, struct pt_regs *regs);
125 /* See comment below, where ftrace_ops_list_func is defined */
126 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
127 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
131 * Traverse the ftrace_global_list, invoking all entries. The reason that we
132 * can use rcu_dereference_raw_notrace() is that elements removed from this list
133 * are simply leaked, so there is no need to interact with a grace-period
134 * mechanism. The rcu_dereference_raw_notrace() calls are needed to handle
135 * concurrent insertions into the ftrace_global_list.
137 * Silly Alpha and silly pointer-speculation compiler optimizations!
139 #define do_for_each_ftrace_op(op, list) \
140 op = rcu_dereference_raw_notrace(list); \
144 * Optimized for just a single item in the list (as that is the normal case).
146 #define while_for_each_ftrace_op(op) \
147 while (likely(op = rcu_dereference_raw_notrace((op)->next)) && \
148 unlikely((op) != &ftrace_list_end))
150 static inline void ftrace_ops_init(struct ftrace_ops *ops)
152 #ifdef CONFIG_DYNAMIC_FTRACE
153 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
154 mutex_init(&ops->local_hash.regex_lock);
155 ops->func_hash = &ops->local_hash;
156 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
162 * ftrace_nr_registered_ops - return number of ops registered
164 * Returns the number of ftrace_ops registered and tracing functions
166 int ftrace_nr_registered_ops(void)
168 struct ftrace_ops *ops;
171 mutex_lock(&ftrace_lock);
173 for (ops = rcu_dereference_protected(ftrace_ops_list,
174 lockdep_is_held(&ftrace_lock));
175 ops != &ftrace_list_end;
176 ops = rcu_dereference_protected(ops->next,
177 lockdep_is_held(&ftrace_lock)))
180 mutex_unlock(&ftrace_lock);
185 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
186 struct ftrace_ops *op, struct pt_regs *regs)
188 struct trace_array *tr = op->private;
190 if (tr && this_cpu_read(tr->trace_buffer.data->ftrace_ignore_pid))
193 op->saved_func(ip, parent_ip, op, regs);
197 * clear_ftrace_function - reset the ftrace function
199 * This NULLs the ftrace function and in essence stops
200 * tracing. There may be lag
202 void clear_ftrace_function(void)
204 ftrace_trace_function = ftrace_stub;
207 static void per_cpu_ops_disable_all(struct ftrace_ops *ops)
211 for_each_possible_cpu(cpu)
212 *per_cpu_ptr(ops->disabled, cpu) = 1;
215 static int per_cpu_ops_alloc(struct ftrace_ops *ops)
217 int __percpu *disabled;
219 if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)))
222 disabled = alloc_percpu(int);
226 ops->disabled = disabled;
227 per_cpu_ops_disable_all(ops);
231 static void ftrace_sync(struct work_struct *work)
234 * This function is just a stub to implement a hard force
235 * of synchronize_sched(). This requires synchronizing
236 * tasks even in userspace and idle.
238 * Yes, function tracing is rude.
242 static void ftrace_sync_ipi(void *data)
244 /* Probably not needed, but do it anyway */
248 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
249 static void update_function_graph_func(void);
251 /* Both enabled by default (can be cleared by function_graph tracer flags */
252 static bool fgraph_sleep_time = true;
253 static bool fgraph_graph_time = true;
256 static inline void update_function_graph_func(void) { }
260 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
263 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
264 * then it needs to call the list anyway.
266 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU |
267 FTRACE_OPS_FL_RCU) || FTRACE_FORCE_LIST_FUNC)
268 return ftrace_ops_list_func;
270 return ftrace_ops_get_func(ops);
273 static void update_ftrace_function(void)
278 * Prepare the ftrace_ops that the arch callback will use.
279 * If there's only one ftrace_ops registered, the ftrace_ops_list
280 * will point to the ops we want.
282 set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
283 lockdep_is_held(&ftrace_lock));
285 /* If there's no ftrace_ops registered, just call the stub function */
286 if (set_function_trace_op == &ftrace_list_end) {
290 * If we are at the end of the list and this ops is
291 * recursion safe and not dynamic and the arch supports passing ops,
292 * then have the mcount trampoline call the function directly.
294 } else if (rcu_dereference_protected(ftrace_ops_list->next,
295 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
296 func = ftrace_ops_get_list_func(ftrace_ops_list);
299 /* Just use the default ftrace_ops */
300 set_function_trace_op = &ftrace_list_end;
301 func = ftrace_ops_list_func;
304 update_function_graph_func();
306 /* If there's no change, then do nothing more here */
307 if (ftrace_trace_function == func)
311 * If we are using the list function, it doesn't care
312 * about the function_trace_ops.
314 if (func == ftrace_ops_list_func) {
315 ftrace_trace_function = func;
317 * Don't even bother setting function_trace_ops,
318 * it would be racy to do so anyway.
323 #ifndef CONFIG_DYNAMIC_FTRACE
325 * For static tracing, we need to be a bit more careful.
326 * The function change takes affect immediately. Thus,
327 * we need to coorditate the setting of the function_trace_ops
328 * with the setting of the ftrace_trace_function.
330 * Set the function to the list ops, which will call the
331 * function we want, albeit indirectly, but it handles the
332 * ftrace_ops and doesn't depend on function_trace_op.
334 ftrace_trace_function = ftrace_ops_list_func;
336 * Make sure all CPUs see this. Yes this is slow, but static
337 * tracing is slow and nasty to have enabled.
339 schedule_on_each_cpu(ftrace_sync);
340 /* Now all cpus are using the list ops. */
341 function_trace_op = set_function_trace_op;
342 /* Make sure the function_trace_op is visible on all CPUs */
344 /* Nasty way to force a rmb on all cpus */
345 smp_call_function(ftrace_sync_ipi, NULL, 1);
346 /* OK, we are all set to update the ftrace_trace_function now! */
347 #endif /* !CONFIG_DYNAMIC_FTRACE */
349 ftrace_trace_function = func;
352 int using_ftrace_ops_list_func(void)
354 return ftrace_trace_function == ftrace_ops_list_func;
357 static void add_ftrace_ops(struct ftrace_ops __rcu **list,
358 struct ftrace_ops *ops)
360 rcu_assign_pointer(ops->next, *list);
363 * We are entering ops into the list but another
364 * CPU might be walking that list. We need to make sure
365 * the ops->next pointer is valid before another CPU sees
366 * the ops pointer included into the list.
368 rcu_assign_pointer(*list, ops);
371 static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
372 struct ftrace_ops *ops)
374 struct ftrace_ops **p;
377 * If we are removing the last function, then simply point
378 * to the ftrace_stub.
380 if (rcu_dereference_protected(*list,
381 lockdep_is_held(&ftrace_lock)) == ops &&
382 rcu_dereference_protected(ops->next,
383 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
384 *list = &ftrace_list_end;
388 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
399 static void ftrace_update_trampoline(struct ftrace_ops *ops);
401 static int __register_ftrace_function(struct ftrace_ops *ops)
403 if (ops->flags & FTRACE_OPS_FL_DELETED)
406 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
409 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
411 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
412 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
413 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
415 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
416 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
419 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
420 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
423 if (!core_kernel_data((unsigned long)ops))
424 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
426 if (ops->flags & FTRACE_OPS_FL_PER_CPU) {
427 if (per_cpu_ops_alloc(ops))
431 add_ftrace_ops(&ftrace_ops_list, ops);
433 /* Always save the function, and reset at unregistering */
434 ops->saved_func = ops->func;
436 if (ftrace_pids_enabled(ops))
437 ops->func = ftrace_pid_func;
439 ftrace_update_trampoline(ops);
442 update_ftrace_function();
447 static int __unregister_ftrace_function(struct ftrace_ops *ops)
451 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
454 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
460 update_ftrace_function();
462 ops->func = ops->saved_func;
467 static void ftrace_update_pid_func(void)
469 struct ftrace_ops *op;
471 /* Only do something if we are tracing something */
472 if (ftrace_trace_function == ftrace_stub)
475 do_for_each_ftrace_op(op, ftrace_ops_list) {
476 if (op->flags & FTRACE_OPS_FL_PID) {
477 op->func = ftrace_pids_enabled(op) ?
478 ftrace_pid_func : op->saved_func;
479 ftrace_update_trampoline(op);
481 } while_for_each_ftrace_op(op);
483 update_ftrace_function();
486 #ifdef CONFIG_FUNCTION_PROFILER
487 struct ftrace_profile {
488 struct hlist_node node;
490 unsigned long counter;
491 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
492 unsigned long long time;
493 unsigned long long time_squared;
497 struct ftrace_profile_page {
498 struct ftrace_profile_page *next;
500 struct ftrace_profile records[];
503 struct ftrace_profile_stat {
505 struct hlist_head *hash;
506 struct ftrace_profile_page *pages;
507 struct ftrace_profile_page *start;
508 struct tracer_stat stat;
511 #define PROFILE_RECORDS_SIZE \
512 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
514 #define PROFILES_PER_PAGE \
515 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
517 static int ftrace_profile_enabled __read_mostly;
519 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
520 static DEFINE_MUTEX(ftrace_profile_lock);
522 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
524 #define FTRACE_PROFILE_HASH_BITS 10
525 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
528 function_stat_next(void *v, int idx)
530 struct ftrace_profile *rec = v;
531 struct ftrace_profile_page *pg;
533 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
539 if ((void *)rec >= (void *)&pg->records[pg->index]) {
543 rec = &pg->records[0];
551 static void *function_stat_start(struct tracer_stat *trace)
553 struct ftrace_profile_stat *stat =
554 container_of(trace, struct ftrace_profile_stat, stat);
556 if (!stat || !stat->start)
559 return function_stat_next(&stat->start->records[0], 0);
562 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
563 /* function graph compares on total time */
564 static int function_stat_cmp(void *p1, void *p2)
566 struct ftrace_profile *a = p1;
567 struct ftrace_profile *b = p2;
569 if (a->time < b->time)
571 if (a->time > b->time)
577 /* not function graph compares against hits */
578 static int function_stat_cmp(void *p1, void *p2)
580 struct ftrace_profile *a = p1;
581 struct ftrace_profile *b = p2;
583 if (a->counter < b->counter)
585 if (a->counter > b->counter)
592 static int function_stat_headers(struct seq_file *m)
594 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
595 seq_puts(m, " Function "
598 "--- ---- --- ---\n");
600 seq_puts(m, " Function Hit\n"
606 static int function_stat_show(struct seq_file *m, void *v)
608 struct ftrace_profile *rec = v;
609 char str[KSYM_SYMBOL_LEN];
611 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
612 static struct trace_seq s;
613 unsigned long long avg;
614 unsigned long long stddev;
616 mutex_lock(&ftrace_profile_lock);
618 /* we raced with function_profile_reset() */
619 if (unlikely(rec->counter == 0)) {
624 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
625 avg = div64_ul(rec->time, rec->counter);
626 if (tracing_thresh && (avg < tracing_thresh))
630 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
631 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
633 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
636 /* Sample standard deviation (s^2) */
637 if (rec->counter <= 1)
641 * Apply Welford's method:
642 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
644 stddev = rec->counter * rec->time_squared -
645 rec->time * rec->time;
648 * Divide only 1000 for ns^2 -> us^2 conversion.
649 * trace_print_graph_duration will divide 1000 again.
651 stddev = div64_ul(stddev,
652 rec->counter * (rec->counter - 1) * 1000);
656 trace_print_graph_duration(rec->time, &s);
657 trace_seq_puts(&s, " ");
658 trace_print_graph_duration(avg, &s);
659 trace_seq_puts(&s, " ");
660 trace_print_graph_duration(stddev, &s);
661 trace_print_seq(m, &s);
665 mutex_unlock(&ftrace_profile_lock);
670 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
672 struct ftrace_profile_page *pg;
674 pg = stat->pages = stat->start;
677 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
682 memset(stat->hash, 0,
683 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
686 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
688 struct ftrace_profile_page *pg;
693 /* If we already allocated, do nothing */
697 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
701 #ifdef CONFIG_DYNAMIC_FTRACE
702 functions = ftrace_update_tot_cnt;
705 * We do not know the number of functions that exist because
706 * dynamic tracing is what counts them. With past experience
707 * we have around 20K functions. That should be more than enough.
708 * It is highly unlikely we will execute every function in
714 pg = stat->start = stat->pages;
716 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
718 for (i = 1; i < pages; i++) {
719 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
730 unsigned long tmp = (unsigned long)pg;
742 static int ftrace_profile_init_cpu(int cpu)
744 struct ftrace_profile_stat *stat;
747 stat = &per_cpu(ftrace_profile_stats, cpu);
750 /* If the profile is already created, simply reset it */
751 ftrace_profile_reset(stat);
756 * We are profiling all functions, but usually only a few thousand
757 * functions are hit. We'll make a hash of 1024 items.
759 size = FTRACE_PROFILE_HASH_SIZE;
761 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
766 /* Preallocate the function profiling pages */
767 if (ftrace_profile_pages_init(stat) < 0) {
776 static int ftrace_profile_init(void)
781 for_each_possible_cpu(cpu) {
782 ret = ftrace_profile_init_cpu(cpu);
790 /* interrupts must be disabled */
791 static struct ftrace_profile *
792 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
794 struct ftrace_profile *rec;
795 struct hlist_head *hhd;
798 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
799 hhd = &stat->hash[key];
801 if (hlist_empty(hhd))
804 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
812 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
813 struct ftrace_profile *rec)
817 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
818 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
822 * The memory is already allocated, this simply finds a new record to use.
824 static struct ftrace_profile *
825 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
827 struct ftrace_profile *rec = NULL;
829 /* prevent recursion (from NMIs) */
830 if (atomic_inc_return(&stat->disabled) != 1)
834 * Try to find the function again since an NMI
835 * could have added it
837 rec = ftrace_find_profiled_func(stat, ip);
841 if (stat->pages->index == PROFILES_PER_PAGE) {
842 if (!stat->pages->next)
844 stat->pages = stat->pages->next;
847 rec = &stat->pages->records[stat->pages->index++];
849 ftrace_add_profile(stat, rec);
852 atomic_dec(&stat->disabled);
858 function_profile_call(unsigned long ip, unsigned long parent_ip,
859 struct ftrace_ops *ops, struct pt_regs *regs)
861 struct ftrace_profile_stat *stat;
862 struct ftrace_profile *rec;
865 if (!ftrace_profile_enabled)
868 local_irq_save(flags);
870 stat = this_cpu_ptr(&ftrace_profile_stats);
871 if (!stat->hash || !ftrace_profile_enabled)
874 rec = ftrace_find_profiled_func(stat, ip);
876 rec = ftrace_profile_alloc(stat, ip);
883 local_irq_restore(flags);
886 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
887 static int profile_graph_entry(struct ftrace_graph_ent *trace)
889 int index = trace->depth;
891 function_profile_call(trace->func, 0, NULL, NULL);
893 /* If function graph is shutting down, ret_stack can be NULL */
894 if (!current->ret_stack)
897 if (index >= 0 && index < FTRACE_RETFUNC_DEPTH)
898 current->ret_stack[index].subtime = 0;
903 static void profile_graph_return(struct ftrace_graph_ret *trace)
905 struct ftrace_profile_stat *stat;
906 unsigned long long calltime;
907 struct ftrace_profile *rec;
910 local_irq_save(flags);
911 stat = this_cpu_ptr(&ftrace_profile_stats);
912 if (!stat->hash || !ftrace_profile_enabled)
915 /* If the calltime was zero'd ignore it */
916 if (!trace->calltime)
919 calltime = trace->rettime - trace->calltime;
921 if (!fgraph_graph_time) {
924 index = trace->depth;
926 /* Append this call time to the parent time to subtract */
928 current->ret_stack[index - 1].subtime += calltime;
930 if (current->ret_stack[index].subtime < calltime)
931 calltime -= current->ret_stack[index].subtime;
936 rec = ftrace_find_profiled_func(stat, trace->func);
938 rec->time += calltime;
939 rec->time_squared += calltime * calltime;
943 local_irq_restore(flags);
946 static int register_ftrace_profiler(void)
948 return register_ftrace_graph(&profile_graph_return,
949 &profile_graph_entry);
952 static void unregister_ftrace_profiler(void)
954 unregister_ftrace_graph();
957 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
958 .func = function_profile_call,
959 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
960 INIT_OPS_HASH(ftrace_profile_ops)
963 static int register_ftrace_profiler(void)
965 return register_ftrace_function(&ftrace_profile_ops);
968 static void unregister_ftrace_profiler(void)
970 unregister_ftrace_function(&ftrace_profile_ops);
972 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
975 ftrace_profile_write(struct file *filp, const char __user *ubuf,
976 size_t cnt, loff_t *ppos)
981 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
987 mutex_lock(&ftrace_profile_lock);
988 if (ftrace_profile_enabled ^ val) {
990 ret = ftrace_profile_init();
996 ret = register_ftrace_profiler();
1001 ftrace_profile_enabled = 1;
1003 ftrace_profile_enabled = 0;
1005 * unregister_ftrace_profiler calls stop_machine
1006 * so this acts like an synchronize_sched.
1008 unregister_ftrace_profiler();
1012 mutex_unlock(&ftrace_profile_lock);
1020 ftrace_profile_read(struct file *filp, char __user *ubuf,
1021 size_t cnt, loff_t *ppos)
1023 char buf[64]; /* big enough to hold a number */
1026 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
1027 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1030 static const struct file_operations ftrace_profile_fops = {
1031 .open = tracing_open_generic,
1032 .read = ftrace_profile_read,
1033 .write = ftrace_profile_write,
1034 .llseek = default_llseek,
1037 /* used to initialize the real stat files */
1038 static struct tracer_stat function_stats __initdata = {
1039 .name = "functions",
1040 .stat_start = function_stat_start,
1041 .stat_next = function_stat_next,
1042 .stat_cmp = function_stat_cmp,
1043 .stat_headers = function_stat_headers,
1044 .stat_show = function_stat_show
1047 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1049 struct ftrace_profile_stat *stat;
1050 struct dentry *entry;
1055 for_each_possible_cpu(cpu) {
1056 stat = &per_cpu(ftrace_profile_stats, cpu);
1058 name = kasprintf(GFP_KERNEL, "function%d", cpu);
1061 * The files created are permanent, if something happens
1062 * we still do not free memory.
1065 "Could not allocate stat file for cpu %d\n",
1069 stat->stat = function_stats;
1070 stat->stat.name = name;
1071 ret = register_stat_tracer(&stat->stat);
1074 "Could not register function stat for cpu %d\n",
1081 entry = tracefs_create_file("function_profile_enabled", 0644,
1082 d_tracer, NULL, &ftrace_profile_fops);
1084 pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
1087 #else /* CONFIG_FUNCTION_PROFILER */
1088 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1091 #endif /* CONFIG_FUNCTION_PROFILER */
1093 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1095 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1096 static int ftrace_graph_active;
1098 # define ftrace_graph_active 0
1101 #ifdef CONFIG_DYNAMIC_FTRACE
1103 static struct ftrace_ops *removed_ops;
1106 * Set when doing a global update, like enabling all recs or disabling them.
1107 * It is not set when just updating a single ftrace_ops.
1109 static bool update_all_ops;
1111 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1112 # error Dynamic ftrace depends on MCOUNT_RECORD
1115 struct ftrace_func_entry {
1116 struct hlist_node hlist;
1120 struct ftrace_func_probe {
1121 struct ftrace_probe_ops *probe_ops;
1122 struct ftrace_ops ops;
1123 struct trace_array *tr;
1124 struct list_head list;
1130 * We make these constant because no one should touch them,
1131 * but they are used as the default "empty hash", to avoid allocating
1132 * it all the time. These are in a read only section such that if
1133 * anyone does try to modify it, it will cause an exception.
1135 static const struct hlist_head empty_buckets[1];
1136 static const struct ftrace_hash empty_hash = {
1137 .buckets = (struct hlist_head *)empty_buckets,
1139 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1141 static struct ftrace_ops global_ops = {
1142 .func = ftrace_stub,
1143 .local_hash.notrace_hash = EMPTY_HASH,
1144 .local_hash.filter_hash = EMPTY_HASH,
1145 INIT_OPS_HASH(global_ops)
1146 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
1147 FTRACE_OPS_FL_INITIALIZED |
1152 * This is used by __kernel_text_address() to return true if the
1153 * address is on a dynamically allocated trampoline that would
1154 * not return true for either core_kernel_text() or
1155 * is_module_text_address().
1157 bool is_ftrace_trampoline(unsigned long addr)
1159 struct ftrace_ops *op;
1163 * Some of the ops may be dynamically allocated,
1164 * they are freed after a synchronize_sched().
1166 preempt_disable_notrace();
1168 do_for_each_ftrace_op(op, ftrace_ops_list) {
1170 * This is to check for dynamically allocated trampolines.
1171 * Trampolines that are in kernel text will have
1172 * core_kernel_text() return true.
1174 if (op->trampoline && op->trampoline_size)
1175 if (addr >= op->trampoline &&
1176 addr < op->trampoline + op->trampoline_size) {
1180 } while_for_each_ftrace_op(op);
1183 preempt_enable_notrace();
1188 struct ftrace_page {
1189 struct ftrace_page *next;
1190 struct dyn_ftrace *records;
1195 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1196 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1198 /* estimate from running different kernels */
1199 #define NR_TO_INIT 10000
1201 static struct ftrace_page *ftrace_pages_start;
1202 static struct ftrace_page *ftrace_pages;
1204 static __always_inline unsigned long
1205 ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1207 if (hash->size_bits > 0)
1208 return hash_long(ip, hash->size_bits);
1213 /* Only use this function if ftrace_hash_empty() has already been tested */
1214 static __always_inline struct ftrace_func_entry *
1215 __ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1218 struct ftrace_func_entry *entry;
1219 struct hlist_head *hhd;
1221 key = ftrace_hash_key(hash, ip);
1222 hhd = &hash->buckets[key];
1224 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1225 if (entry->ip == ip)
1232 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1233 * @hash: The hash to look at
1234 * @ip: The instruction pointer to test
1236 * Search a given @hash to see if a given instruction pointer (@ip)
1239 * Returns the entry that holds the @ip if found. NULL otherwise.
1241 struct ftrace_func_entry *
1242 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1244 if (ftrace_hash_empty(hash))
1247 return __ftrace_lookup_ip(hash, ip);
1250 static void __add_hash_entry(struct ftrace_hash *hash,
1251 struct ftrace_func_entry *entry)
1253 struct hlist_head *hhd;
1256 key = ftrace_hash_key(hash, entry->ip);
1257 hhd = &hash->buckets[key];
1258 hlist_add_head(&entry->hlist, hhd);
1262 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1264 struct ftrace_func_entry *entry;
1266 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1271 __add_hash_entry(hash, entry);
1277 free_hash_entry(struct ftrace_hash *hash,
1278 struct ftrace_func_entry *entry)
1280 hlist_del(&entry->hlist);
1286 remove_hash_entry(struct ftrace_hash *hash,
1287 struct ftrace_func_entry *entry)
1289 hlist_del_rcu(&entry->hlist);
1293 static void ftrace_hash_clear(struct ftrace_hash *hash)
1295 struct hlist_head *hhd;
1296 struct hlist_node *tn;
1297 struct ftrace_func_entry *entry;
1298 int size = 1 << hash->size_bits;
1304 for (i = 0; i < size; i++) {
1305 hhd = &hash->buckets[i];
1306 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1307 free_hash_entry(hash, entry);
1309 FTRACE_WARN_ON(hash->count);
1312 static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1314 list_del(&ftrace_mod->list);
1315 kfree(ftrace_mod->module);
1316 kfree(ftrace_mod->func);
1320 static void clear_ftrace_mod_list(struct list_head *head)
1322 struct ftrace_mod_load *p, *n;
1324 /* stack tracer isn't supported yet */
1328 mutex_lock(&ftrace_lock);
1329 list_for_each_entry_safe(p, n, head, list)
1331 mutex_unlock(&ftrace_lock);
1334 static void free_ftrace_hash(struct ftrace_hash *hash)
1336 if (!hash || hash == EMPTY_HASH)
1338 ftrace_hash_clear(hash);
1339 kfree(hash->buckets);
1343 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1345 struct ftrace_hash *hash;
1347 hash = container_of(rcu, struct ftrace_hash, rcu);
1348 free_ftrace_hash(hash);
1351 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1353 if (!hash || hash == EMPTY_HASH)
1355 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1358 void ftrace_free_filter(struct ftrace_ops *ops)
1360 ftrace_ops_init(ops);
1361 free_ftrace_hash(ops->func_hash->filter_hash);
1362 free_ftrace_hash(ops->func_hash->notrace_hash);
1365 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1367 struct ftrace_hash *hash;
1370 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1374 size = 1 << size_bits;
1375 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1377 if (!hash->buckets) {
1382 hash->size_bits = size_bits;
1388 static int ftrace_add_mod(struct trace_array *tr,
1389 const char *func, const char *module,
1392 struct ftrace_mod_load *ftrace_mod;
1393 struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1395 ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1399 INIT_LIST_HEAD(&ftrace_mod->list);
1400 ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1401 ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1402 ftrace_mod->enable = enable;
1404 if (!ftrace_mod->func || !ftrace_mod->module)
1407 list_add(&ftrace_mod->list, mod_head);
1412 free_ftrace_mod(ftrace_mod);
1417 static struct ftrace_hash *
1418 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1420 struct ftrace_func_entry *entry;
1421 struct ftrace_hash *new_hash;
1426 new_hash = alloc_ftrace_hash(size_bits);
1431 new_hash->flags = hash->flags;
1434 if (ftrace_hash_empty(hash))
1437 size = 1 << hash->size_bits;
1438 for (i = 0; i < size; i++) {
1439 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1440 ret = add_hash_entry(new_hash, entry->ip);
1446 FTRACE_WARN_ON(new_hash->count != hash->count);
1451 free_ftrace_hash(new_hash);
1456 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1458 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1460 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1461 struct ftrace_hash *new_hash);
1463 static struct ftrace_hash *
1464 __ftrace_hash_move(struct ftrace_hash *src)
1466 struct ftrace_func_entry *entry;
1467 struct hlist_node *tn;
1468 struct hlist_head *hhd;
1469 struct ftrace_hash *new_hash;
1470 int size = src->count;
1475 * If the new source is empty, just return the empty_hash.
1477 if (ftrace_hash_empty(src))
1481 * Make the hash size about 1/2 the # found
1483 for (size /= 2; size; size >>= 1)
1486 /* Don't allocate too much */
1487 if (bits > FTRACE_HASH_MAX_BITS)
1488 bits = FTRACE_HASH_MAX_BITS;
1490 new_hash = alloc_ftrace_hash(bits);
1494 new_hash->flags = src->flags;
1496 size = 1 << src->size_bits;
1497 for (i = 0; i < size; i++) {
1498 hhd = &src->buckets[i];
1499 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1500 remove_hash_entry(src, entry);
1501 __add_hash_entry(new_hash, entry);
1509 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1510 struct ftrace_hash **dst, struct ftrace_hash *src)
1512 struct ftrace_hash *new_hash;
1515 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1516 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1519 new_hash = __ftrace_hash_move(src);
1523 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1525 /* IPMODIFY should be updated only when filter_hash updating */
1526 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1528 free_ftrace_hash(new_hash);
1534 * Remove the current set, update the hash and add
1537 ftrace_hash_rec_disable_modify(ops, enable);
1539 rcu_assign_pointer(*dst, new_hash);
1541 ftrace_hash_rec_enable_modify(ops, enable);
1546 static bool hash_contains_ip(unsigned long ip,
1547 struct ftrace_ops_hash *hash)
1550 * The function record is a match if it exists in the filter
1551 * hash and not in the notrace hash. Note, an emty hash is
1552 * considered a match for the filter hash, but an empty
1553 * notrace hash is considered not in the notrace hash.
1555 return (ftrace_hash_empty(hash->filter_hash) ||
1556 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1557 (ftrace_hash_empty(hash->notrace_hash) ||
1558 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1562 * Test the hashes for this ops to see if we want to call
1563 * the ops->func or not.
1565 * It's a match if the ip is in the ops->filter_hash or
1566 * the filter_hash does not exist or is empty,
1568 * the ip is not in the ops->notrace_hash.
1570 * This needs to be called with preemption disabled as
1571 * the hashes are freed with call_rcu_sched().
1574 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1576 struct ftrace_ops_hash hash;
1579 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1581 * There's a small race when adding ops that the ftrace handler
1582 * that wants regs, may be called without them. We can not
1583 * allow that handler to be called if regs is NULL.
1585 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1589 rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1590 rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1592 if (hash_contains_ip(ip, &hash))
1601 * This is a double for. Do not use 'break' to break out of the loop,
1602 * you must use a goto.
1604 #define do_for_each_ftrace_rec(pg, rec) \
1605 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1607 for (_____i = 0; _____i < pg->index; _____i++) { \
1608 rec = &pg->records[_____i];
1610 #define while_for_each_ftrace_rec() \
1615 static int ftrace_cmp_recs(const void *a, const void *b)
1617 const struct dyn_ftrace *key = a;
1618 const struct dyn_ftrace *rec = b;
1620 if (key->flags < rec->ip)
1622 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1628 * ftrace_location_range - return the first address of a traced location
1629 * if it touches the given ip range
1630 * @start: start of range to search.
1631 * @end: end of range to search (inclusive). @end points to the last byte
1634 * Returns rec->ip if the related ftrace location is a least partly within
1635 * the given address range. That is, the first address of the instruction
1636 * that is either a NOP or call to the function tracer. It checks the ftrace
1637 * internal tables to determine if the address belongs or not.
1639 unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1641 struct ftrace_page *pg;
1642 struct dyn_ftrace *rec;
1643 struct dyn_ftrace key;
1646 key.flags = end; /* overload flags, as it is unsigned long */
1648 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1649 if (pg->index == 0 ||
1650 end < pg->records[0].ip ||
1651 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1653 rec = bsearch(&key, pg->records, pg->index,
1654 sizeof(struct dyn_ftrace),
1664 * ftrace_location - return true if the ip giving is a traced location
1665 * @ip: the instruction pointer to check
1667 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1668 * That is, the instruction that is either a NOP or call to
1669 * the function tracer. It checks the ftrace internal tables to
1670 * determine if the address belongs or not.
1672 unsigned long ftrace_location(unsigned long ip)
1674 return ftrace_location_range(ip, ip);
1678 * ftrace_text_reserved - return true if range contains an ftrace location
1679 * @start: start of range to search
1680 * @end: end of range to search (inclusive). @end points to the last byte to check.
1682 * Returns 1 if @start and @end contains a ftrace location.
1683 * That is, the instruction that is either a NOP or call to
1684 * the function tracer. It checks the ftrace internal tables to
1685 * determine if the address belongs or not.
1687 int ftrace_text_reserved(const void *start, const void *end)
1691 ret = ftrace_location_range((unsigned long)start,
1692 (unsigned long)end);
1697 /* Test if ops registered to this rec needs regs */
1698 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1700 struct ftrace_ops *ops;
1701 bool keep_regs = false;
1703 for (ops = ftrace_ops_list;
1704 ops != &ftrace_list_end; ops = ops->next) {
1705 /* pass rec in as regs to have non-NULL val */
1706 if (ftrace_ops_test(ops, rec->ip, rec)) {
1707 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1717 static struct ftrace_ops *
1718 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1719 static struct ftrace_ops *
1720 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude);
1721 static struct ftrace_ops *
1722 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1724 static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1728 struct ftrace_hash *hash;
1729 struct ftrace_hash *other_hash;
1730 struct ftrace_page *pg;
1731 struct dyn_ftrace *rec;
1732 bool update = false;
1736 /* Only update if the ops has been registered */
1737 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1741 * In the filter_hash case:
1742 * If the count is zero, we update all records.
1743 * Otherwise we just update the items in the hash.
1745 * In the notrace_hash case:
1746 * We enable the update in the hash.
1747 * As disabling notrace means enabling the tracing,
1748 * and enabling notrace means disabling, the inc variable
1752 hash = ops->func_hash->filter_hash;
1753 other_hash = ops->func_hash->notrace_hash;
1754 if (ftrace_hash_empty(hash))
1758 hash = ops->func_hash->notrace_hash;
1759 other_hash = ops->func_hash->filter_hash;
1761 * If the notrace hash has no items,
1762 * then there's nothing to do.
1764 if (ftrace_hash_empty(hash))
1768 do_for_each_ftrace_rec(pg, rec) {
1769 int in_other_hash = 0;
1773 if (rec->flags & FTRACE_FL_DISABLED)
1778 * Only the filter_hash affects all records.
1779 * Update if the record is not in the notrace hash.
1781 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1784 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1785 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1788 * If filter_hash is set, we want to match all functions
1789 * that are in the hash but not in the other hash.
1791 * If filter_hash is not set, then we are decrementing.
1792 * That means we match anything that is in the hash
1793 * and also in the other_hash. That is, we need to turn
1794 * off functions in the other hash because they are disabled
1797 if (filter_hash && in_hash && !in_other_hash)
1799 else if (!filter_hash && in_hash &&
1800 (in_other_hash || ftrace_hash_empty(other_hash)))
1808 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1812 * If there's only a single callback registered to a
1813 * function, and the ops has a trampoline registered
1814 * for it, then we can call it directly.
1816 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1817 rec->flags |= FTRACE_FL_TRAMP;
1820 * If we are adding another function callback
1821 * to this function, and the previous had a
1822 * custom trampoline in use, then we need to go
1823 * back to the default trampoline.
1825 rec->flags &= ~FTRACE_FL_TRAMP;
1828 * If any ops wants regs saved for this function
1829 * then all ops will get saved regs.
1831 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1832 rec->flags |= FTRACE_FL_REGS;
1834 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1839 * If the rec had REGS enabled and the ops that is
1840 * being removed had REGS set, then see if there is
1841 * still any ops for this record that wants regs.
1842 * If not, we can stop recording them.
1844 if (ftrace_rec_count(rec) > 0 &&
1845 rec->flags & FTRACE_FL_REGS &&
1846 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1847 if (!test_rec_ops_needs_regs(rec))
1848 rec->flags &= ~FTRACE_FL_REGS;
1852 * The TRAMP needs to be set only if rec count
1853 * is decremented to one, and the ops that is
1854 * left has a trampoline. As TRAMP can only be
1855 * enabled if there is only a single ops attached
1858 if (ftrace_rec_count(rec) == 1 &&
1859 ftrace_find_tramp_ops_any_other(rec, ops))
1860 rec->flags |= FTRACE_FL_TRAMP;
1862 rec->flags &= ~FTRACE_FL_TRAMP;
1865 * flags will be cleared in ftrace_check_record()
1866 * if rec count is zero.
1871 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1872 update |= ftrace_test_record(rec, 1) != FTRACE_UPDATE_IGNORE;
1874 /* Shortcut, if we handled all records, we are done. */
1875 if (!all && count == hash->count)
1877 } while_for_each_ftrace_rec();
1882 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1885 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1888 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1891 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1894 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1895 int filter_hash, int inc)
1897 struct ftrace_ops *op;
1899 __ftrace_hash_rec_update(ops, filter_hash, inc);
1901 if (ops->func_hash != &global_ops.local_hash)
1905 * If the ops shares the global_ops hash, then we need to update
1906 * all ops that are enabled and use this hash.
1908 do_for_each_ftrace_op(op, ftrace_ops_list) {
1912 if (op->func_hash == &global_ops.local_hash)
1913 __ftrace_hash_rec_update(op, filter_hash, inc);
1914 } while_for_each_ftrace_op(op);
1917 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1920 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1923 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1926 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1930 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1931 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1932 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1933 * Note that old_hash and new_hash has below meanings
1934 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1935 * - If the hash is EMPTY_HASH, it hits nothing
1936 * - Anything else hits the recs which match the hash entries.
1938 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1939 struct ftrace_hash *old_hash,
1940 struct ftrace_hash *new_hash)
1942 struct ftrace_page *pg;
1943 struct dyn_ftrace *rec, *end = NULL;
1946 /* Only update if the ops has been registered */
1947 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1950 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1954 * Since the IPMODIFY is a very address sensitive action, we do not
1955 * allow ftrace_ops to set all functions to new hash.
1957 if (!new_hash || !old_hash)
1960 /* Update rec->flags */
1961 do_for_each_ftrace_rec(pg, rec) {
1963 if (rec->flags & FTRACE_FL_DISABLED)
1966 /* We need to update only differences of filter_hash */
1967 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1968 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1969 if (in_old == in_new)
1973 /* New entries must ensure no others are using it */
1974 if (rec->flags & FTRACE_FL_IPMODIFY)
1976 rec->flags |= FTRACE_FL_IPMODIFY;
1977 } else /* Removed entry */
1978 rec->flags &= ~FTRACE_FL_IPMODIFY;
1979 } while_for_each_ftrace_rec();
1986 /* Roll back what we did above */
1987 do_for_each_ftrace_rec(pg, rec) {
1989 if (rec->flags & FTRACE_FL_DISABLED)
1995 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1996 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1997 if (in_old == in_new)
2001 rec->flags &= ~FTRACE_FL_IPMODIFY;
2003 rec->flags |= FTRACE_FL_IPMODIFY;
2004 } while_for_each_ftrace_rec();
2010 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
2012 struct ftrace_hash *hash = ops->func_hash->filter_hash;
2014 if (ftrace_hash_empty(hash))
2017 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
2020 /* Disabling always succeeds */
2021 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
2023 struct ftrace_hash *hash = ops->func_hash->filter_hash;
2025 if (ftrace_hash_empty(hash))
2028 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
2031 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
2032 struct ftrace_hash *new_hash)
2034 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
2036 if (ftrace_hash_empty(old_hash))
2039 if (ftrace_hash_empty(new_hash))
2042 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
2045 static void print_ip_ins(const char *fmt, const unsigned char *p)
2047 char ins[MCOUNT_INSN_SIZE];
2050 if (probe_kernel_read(ins, p, MCOUNT_INSN_SIZE)) {
2051 printk(KERN_CONT "%s[FAULT] %px\n", fmt, p);
2055 printk(KERN_CONT "%s", fmt);
2057 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
2058 printk(KERN_CONT "%s%02x", i ? ":" : "", ins[i]);
2061 enum ftrace_bug_type ftrace_bug_type;
2062 const void *ftrace_expected;
2064 static void print_bug_type(void)
2066 switch (ftrace_bug_type) {
2067 case FTRACE_BUG_UNKNOWN:
2069 case FTRACE_BUG_INIT:
2070 pr_info("Initializing ftrace call sites\n");
2072 case FTRACE_BUG_NOP:
2073 pr_info("Setting ftrace call site to NOP\n");
2075 case FTRACE_BUG_CALL:
2076 pr_info("Setting ftrace call site to call ftrace function\n");
2078 case FTRACE_BUG_UPDATE:
2079 pr_info("Updating ftrace call site to call a different ftrace function\n");
2085 * ftrace_bug - report and shutdown function tracer
2086 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2087 * @rec: The record that failed
2089 * The arch code that enables or disables the function tracing
2090 * can call ftrace_bug() when it has detected a problem in
2091 * modifying the code. @failed should be one of either:
2092 * EFAULT - if the problem happens on reading the @ip address
2093 * EINVAL - if what is read at @ip is not what was expected
2094 * EPERM - if the problem happens on writting to the @ip address
2096 void ftrace_bug(int failed, struct dyn_ftrace *rec)
2098 unsigned long ip = rec ? rec->ip : 0;
2102 FTRACE_WARN_ON_ONCE(1);
2103 pr_info("ftrace faulted on modifying ");
2107 FTRACE_WARN_ON_ONCE(1);
2108 pr_info("ftrace failed to modify ");
2110 print_ip_ins(" actual: ", (unsigned char *)ip);
2112 if (ftrace_expected) {
2113 print_ip_ins(" expected: ", ftrace_expected);
2118 FTRACE_WARN_ON_ONCE(1);
2119 pr_info("ftrace faulted on writing ");
2123 FTRACE_WARN_ON_ONCE(1);
2124 pr_info("ftrace faulted on unknown error ");
2129 struct ftrace_ops *ops = NULL;
2131 pr_info("ftrace record flags: %lx\n", rec->flags);
2132 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2133 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2134 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2135 ops = ftrace_find_tramp_ops_any(rec);
2138 pr_cont("\ttramp: %pS (%pS)",
2139 (void *)ops->trampoline,
2141 ops = ftrace_find_tramp_ops_next(rec, ops);
2144 pr_cont("\ttramp: ERROR!");
2147 ip = ftrace_get_addr_curr(rec);
2148 pr_cont("\n expected tramp: %lx\n", ip);
2152 static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
2154 unsigned long flag = 0UL;
2156 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2158 if (rec->flags & FTRACE_FL_DISABLED)
2159 return FTRACE_UPDATE_IGNORE;
2162 * If we are updating calls:
2164 * If the record has a ref count, then we need to enable it
2165 * because someone is using it.
2167 * Otherwise we make sure its disabled.
2169 * If we are disabling calls, then disable all records that
2172 if (enable && ftrace_rec_count(rec))
2173 flag = FTRACE_FL_ENABLED;
2176 * If enabling and the REGS flag does not match the REGS_EN, or
2177 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2178 * this record. Set flags to fail the compare against ENABLED.
2181 if (!(rec->flags & FTRACE_FL_REGS) !=
2182 !(rec->flags & FTRACE_FL_REGS_EN))
2183 flag |= FTRACE_FL_REGS;
2185 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2186 !(rec->flags & FTRACE_FL_TRAMP_EN))
2187 flag |= FTRACE_FL_TRAMP;
2190 /* If the state of this record hasn't changed, then do nothing */
2191 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2192 return FTRACE_UPDATE_IGNORE;
2195 /* Save off if rec is being enabled (for return value) */
2196 flag ^= rec->flags & FTRACE_FL_ENABLED;
2199 rec->flags |= FTRACE_FL_ENABLED;
2200 if (flag & FTRACE_FL_REGS) {
2201 if (rec->flags & FTRACE_FL_REGS)
2202 rec->flags |= FTRACE_FL_REGS_EN;
2204 rec->flags &= ~FTRACE_FL_REGS_EN;
2206 if (flag & FTRACE_FL_TRAMP) {
2207 if (rec->flags & FTRACE_FL_TRAMP)
2208 rec->flags |= FTRACE_FL_TRAMP_EN;
2210 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2215 * If this record is being updated from a nop, then
2216 * return UPDATE_MAKE_CALL.
2218 * return UPDATE_MODIFY_CALL to tell the caller to convert
2219 * from the save regs, to a non-save regs function or
2220 * vice versa, or from a trampoline call.
2222 if (flag & FTRACE_FL_ENABLED) {
2223 ftrace_bug_type = FTRACE_BUG_CALL;
2224 return FTRACE_UPDATE_MAKE_CALL;
2227 ftrace_bug_type = FTRACE_BUG_UPDATE;
2228 return FTRACE_UPDATE_MODIFY_CALL;
2232 /* If there's no more users, clear all flags */
2233 if (!ftrace_rec_count(rec))
2237 * Just disable the record, but keep the ops TRAMP
2238 * and REGS states. The _EN flags must be disabled though.
2240 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2244 ftrace_bug_type = FTRACE_BUG_NOP;
2245 return FTRACE_UPDATE_MAKE_NOP;
2249 * ftrace_update_record, set a record that now is tracing or not
2250 * @rec: the record to update
2251 * @enable: set to 1 if the record is tracing, zero to force disable
2253 * The records that represent all functions that can be traced need
2254 * to be updated when tracing has been enabled.
2256 int ftrace_update_record(struct dyn_ftrace *rec, int enable)
2258 return ftrace_check_record(rec, enable, 1);
2262 * ftrace_test_record, check if the record has been enabled or not
2263 * @rec: the record to test
2264 * @enable: set to 1 to check if enabled, 0 if it is disabled
2266 * The arch code may need to test if a record is already set to
2267 * tracing to determine how to modify the function code that it
2270 int ftrace_test_record(struct dyn_ftrace *rec, int enable)
2272 return ftrace_check_record(rec, enable, 0);
2275 static struct ftrace_ops *
2276 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2278 struct ftrace_ops *op;
2279 unsigned long ip = rec->ip;
2281 do_for_each_ftrace_op(op, ftrace_ops_list) {
2283 if (!op->trampoline)
2286 if (hash_contains_ip(ip, op->func_hash))
2288 } while_for_each_ftrace_op(op);
2293 static struct ftrace_ops *
2294 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude)
2296 struct ftrace_ops *op;
2297 unsigned long ip = rec->ip;
2299 do_for_each_ftrace_op(op, ftrace_ops_list) {
2301 if (op == op_exclude || !op->trampoline)
2304 if (hash_contains_ip(ip, op->func_hash))
2306 } while_for_each_ftrace_op(op);
2311 static struct ftrace_ops *
2312 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2313 struct ftrace_ops *op)
2315 unsigned long ip = rec->ip;
2317 while_for_each_ftrace_op(op) {
2319 if (!op->trampoline)
2322 if (hash_contains_ip(ip, op->func_hash))
2329 static struct ftrace_ops *
2330 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2332 struct ftrace_ops *op;
2333 unsigned long ip = rec->ip;
2336 * Need to check removed ops first.
2337 * If they are being removed, and this rec has a tramp,
2338 * and this rec is in the ops list, then it would be the
2339 * one with the tramp.
2342 if (hash_contains_ip(ip, &removed_ops->old_hash))
2347 * Need to find the current trampoline for a rec.
2348 * Now, a trampoline is only attached to a rec if there
2349 * was a single 'ops' attached to it. But this can be called
2350 * when we are adding another op to the rec or removing the
2351 * current one. Thus, if the op is being added, we can
2352 * ignore it because it hasn't attached itself to the rec
2355 * If an ops is being modified (hooking to different functions)
2356 * then we don't care about the new functions that are being
2357 * added, just the old ones (that are probably being removed).
2359 * If we are adding an ops to a function that already is using
2360 * a trampoline, it needs to be removed (trampolines are only
2361 * for single ops connected), then an ops that is not being
2362 * modified also needs to be checked.
2364 do_for_each_ftrace_op(op, ftrace_ops_list) {
2366 if (!op->trampoline)
2370 * If the ops is being added, it hasn't gotten to
2371 * the point to be removed from this tree yet.
2373 if (op->flags & FTRACE_OPS_FL_ADDING)
2378 * If the ops is being modified and is in the old
2379 * hash, then it is probably being removed from this
2382 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2383 hash_contains_ip(ip, &op->old_hash))
2386 * If the ops is not being added or modified, and it's
2387 * in its normal filter hash, then this must be the one
2390 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2391 hash_contains_ip(ip, op->func_hash))
2394 } while_for_each_ftrace_op(op);
2399 static struct ftrace_ops *
2400 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2402 struct ftrace_ops *op;
2403 unsigned long ip = rec->ip;
2405 do_for_each_ftrace_op(op, ftrace_ops_list) {
2406 /* pass rec in as regs to have non-NULL val */
2407 if (hash_contains_ip(ip, op->func_hash))
2409 } while_for_each_ftrace_op(op);
2415 * ftrace_get_addr_new - Get the call address to set to
2416 * @rec: The ftrace record descriptor
2418 * If the record has the FTRACE_FL_REGS set, that means that it
2419 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2420 * is not not set, then it wants to convert to the normal callback.
2422 * Returns the address of the trampoline to set to
2424 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2426 struct ftrace_ops *ops;
2428 /* Trampolines take precedence over regs */
2429 if (rec->flags & FTRACE_FL_TRAMP) {
2430 ops = ftrace_find_tramp_ops_new(rec);
2431 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2432 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2433 (void *)rec->ip, (void *)rec->ip, rec->flags);
2434 /* Ftrace is shutting down, return anything */
2435 return (unsigned long)FTRACE_ADDR;
2437 return ops->trampoline;
2440 if (rec->flags & FTRACE_FL_REGS)
2441 return (unsigned long)FTRACE_REGS_ADDR;
2443 return (unsigned long)FTRACE_ADDR;
2447 * ftrace_get_addr_curr - Get the call address that is already there
2448 * @rec: The ftrace record descriptor
2450 * The FTRACE_FL_REGS_EN is set when the record already points to
2451 * a function that saves all the regs. Basically the '_EN' version
2452 * represents the current state of the function.
2454 * Returns the address of the trampoline that is currently being called
2456 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2458 struct ftrace_ops *ops;
2460 /* Trampolines take precedence over regs */
2461 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2462 ops = ftrace_find_tramp_ops_curr(rec);
2463 if (FTRACE_WARN_ON(!ops)) {
2464 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2465 (void *)rec->ip, (void *)rec->ip);
2466 /* Ftrace is shutting down, return anything */
2467 return (unsigned long)FTRACE_ADDR;
2469 return ops->trampoline;
2472 if (rec->flags & FTRACE_FL_REGS_EN)
2473 return (unsigned long)FTRACE_REGS_ADDR;
2475 return (unsigned long)FTRACE_ADDR;
2479 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
2481 unsigned long ftrace_old_addr;
2482 unsigned long ftrace_addr;
2485 ftrace_addr = ftrace_get_addr_new(rec);
2487 /* This needs to be done before we call ftrace_update_record */
2488 ftrace_old_addr = ftrace_get_addr_curr(rec);
2490 ret = ftrace_update_record(rec, enable);
2492 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2495 case FTRACE_UPDATE_IGNORE:
2498 case FTRACE_UPDATE_MAKE_CALL:
2499 ftrace_bug_type = FTRACE_BUG_CALL;
2500 return ftrace_make_call(rec, ftrace_addr);
2502 case FTRACE_UPDATE_MAKE_NOP:
2503 ftrace_bug_type = FTRACE_BUG_NOP;
2504 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2506 case FTRACE_UPDATE_MODIFY_CALL:
2507 ftrace_bug_type = FTRACE_BUG_UPDATE;
2508 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2511 return -1; /* unknow ftrace bug */
2514 void __weak ftrace_replace_code(int enable)
2516 struct dyn_ftrace *rec;
2517 struct ftrace_page *pg;
2520 if (unlikely(ftrace_disabled))
2523 do_for_each_ftrace_rec(pg, rec) {
2525 if (rec->flags & FTRACE_FL_DISABLED)
2528 failed = __ftrace_replace_code(rec, enable);
2530 ftrace_bug(failed, rec);
2531 /* Stop processing */
2534 } while_for_each_ftrace_rec();
2537 struct ftrace_rec_iter {
2538 struct ftrace_page *pg;
2543 * ftrace_rec_iter_start, start up iterating over traced functions
2545 * Returns an iterator handle that is used to iterate over all
2546 * the records that represent address locations where functions
2549 * May return NULL if no records are available.
2551 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2554 * We only use a single iterator.
2555 * Protected by the ftrace_lock mutex.
2557 static struct ftrace_rec_iter ftrace_rec_iter;
2558 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2560 iter->pg = ftrace_pages_start;
2563 /* Could have empty pages */
2564 while (iter->pg && !iter->pg->index)
2565 iter->pg = iter->pg->next;
2574 * ftrace_rec_iter_next, get the next record to process.
2575 * @iter: The handle to the iterator.
2577 * Returns the next iterator after the given iterator @iter.
2579 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2583 if (iter->index >= iter->pg->index) {
2584 iter->pg = iter->pg->next;
2587 /* Could have empty pages */
2588 while (iter->pg && !iter->pg->index)
2589 iter->pg = iter->pg->next;
2599 * ftrace_rec_iter_record, get the record at the iterator location
2600 * @iter: The current iterator location
2602 * Returns the record that the current @iter is at.
2604 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2606 return &iter->pg->records[iter->index];
2610 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
2614 if (unlikely(ftrace_disabled))
2617 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
2619 ftrace_bug_type = FTRACE_BUG_INIT;
2620 ftrace_bug(ret, rec);
2627 * archs can override this function if they must do something
2628 * before the modifying code is performed.
2630 int __weak ftrace_arch_code_modify_prepare(void)
2636 * archs can override this function if they must do something
2637 * after the modifying code is performed.
2639 int __weak ftrace_arch_code_modify_post_process(void)
2644 void ftrace_modify_all_code(int command)
2646 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2650 * If the ftrace_caller calls a ftrace_ops func directly,
2651 * we need to make sure that it only traces functions it
2652 * expects to trace. When doing the switch of functions,
2653 * we need to update to the ftrace_ops_list_func first
2654 * before the transition between old and new calls are set,
2655 * as the ftrace_ops_list_func will check the ops hashes
2656 * to make sure the ops are having the right functions
2660 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2661 if (FTRACE_WARN_ON(err))
2665 if (command & FTRACE_UPDATE_CALLS)
2666 ftrace_replace_code(1);
2667 else if (command & FTRACE_DISABLE_CALLS)
2668 ftrace_replace_code(0);
2670 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2671 function_trace_op = set_function_trace_op;
2673 /* If irqs are disabled, we are in stop machine */
2674 if (!irqs_disabled())
2675 smp_call_function(ftrace_sync_ipi, NULL, 1);
2676 err = ftrace_update_ftrace_func(ftrace_trace_function);
2677 if (FTRACE_WARN_ON(err))
2681 if (command & FTRACE_START_FUNC_RET)
2682 err = ftrace_enable_ftrace_graph_caller();
2683 else if (command & FTRACE_STOP_FUNC_RET)
2684 err = ftrace_disable_ftrace_graph_caller();
2685 FTRACE_WARN_ON(err);
2688 static int __ftrace_modify_code(void *data)
2690 int *command = data;
2692 ftrace_modify_all_code(*command);
2698 * ftrace_run_stop_machine, go back to the stop machine method
2699 * @command: The command to tell ftrace what to do
2701 * If an arch needs to fall back to the stop machine method, the
2702 * it can call this function.
2704 void ftrace_run_stop_machine(int command)
2706 stop_machine(__ftrace_modify_code, &command, NULL);
2710 * arch_ftrace_update_code, modify the code to trace or not trace
2711 * @command: The command that needs to be done
2713 * Archs can override this function if it does not need to
2714 * run stop_machine() to modify code.
2716 void __weak arch_ftrace_update_code(int command)
2718 ftrace_run_stop_machine(command);
2721 static void ftrace_run_update_code(int command)
2725 ret = ftrace_arch_code_modify_prepare();
2726 FTRACE_WARN_ON(ret);
2731 * By default we use stop_machine() to modify the code.
2732 * But archs can do what ever they want as long as it
2733 * is safe. The stop_machine() is the safest, but also
2734 * produces the most overhead.
2736 arch_ftrace_update_code(command);
2738 ret = ftrace_arch_code_modify_post_process();
2739 FTRACE_WARN_ON(ret);
2742 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2743 struct ftrace_ops_hash *old_hash)
2745 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2746 ops->old_hash.filter_hash = old_hash->filter_hash;
2747 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2748 ftrace_run_update_code(command);
2749 ops->old_hash.filter_hash = NULL;
2750 ops->old_hash.notrace_hash = NULL;
2751 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2754 static ftrace_func_t saved_ftrace_func;
2755 static int ftrace_start_up;
2757 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2761 static void per_cpu_ops_free(struct ftrace_ops *ops)
2763 free_percpu(ops->disabled);
2766 static void ftrace_startup_enable(int command)
2768 if (saved_ftrace_func != ftrace_trace_function) {
2769 saved_ftrace_func = ftrace_trace_function;
2770 command |= FTRACE_UPDATE_TRACE_FUNC;
2773 if (!command || !ftrace_enabled)
2776 ftrace_run_update_code(command);
2779 static void ftrace_startup_all(int command)
2781 update_all_ops = true;
2782 ftrace_startup_enable(command);
2783 update_all_ops = false;
2786 static int ftrace_startup(struct ftrace_ops *ops, int command)
2790 if (unlikely(ftrace_disabled))
2793 ret = __register_ftrace_function(ops);
2800 * Note that ftrace probes uses this to start up
2801 * and modify functions it will probe. But we still
2802 * set the ADDING flag for modification, as probes
2803 * do not have trampolines. If they add them in the
2804 * future, then the probes will need to distinguish
2805 * between adding and updating probes.
2807 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2809 ret = ftrace_hash_ipmodify_enable(ops);
2811 /* Rollback registration process */
2812 __unregister_ftrace_function(ops);
2814 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2818 if (ftrace_hash_rec_enable(ops, 1))
2819 command |= FTRACE_UPDATE_CALLS;
2821 ftrace_startup_enable(command);
2824 * If ftrace is in an undefined state, we just remove ops from list
2825 * to prevent the NULL pointer, instead of totally rolling it back and
2826 * free trampoline, because those actions could cause further damage.
2828 if (unlikely(ftrace_disabled)) {
2829 __unregister_ftrace_function(ops);
2833 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2838 static int ftrace_shutdown(struct ftrace_ops *ops, int command)
2842 if (unlikely(ftrace_disabled))
2845 ret = __unregister_ftrace_function(ops);
2851 * Just warn in case of unbalance, no need to kill ftrace, it's not
2852 * critical but the ftrace_call callers may be never nopped again after
2853 * further ftrace uses.
2855 WARN_ON_ONCE(ftrace_start_up < 0);
2857 /* Disabling ipmodify never fails */
2858 ftrace_hash_ipmodify_disable(ops);
2860 if (ftrace_hash_rec_disable(ops, 1))
2861 command |= FTRACE_UPDATE_CALLS;
2863 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2865 if (saved_ftrace_func != ftrace_trace_function) {
2866 saved_ftrace_func = ftrace_trace_function;
2867 command |= FTRACE_UPDATE_TRACE_FUNC;
2870 if (!command || !ftrace_enabled) {
2872 * If these are dynamic or per_cpu ops, they still
2873 * need their data freed. Since, function tracing is
2874 * not currently active, we can just free them
2875 * without synchronizing all CPUs.
2877 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU))
2884 * If the ops uses a trampoline, then it needs to be
2885 * tested first on update.
2887 ops->flags |= FTRACE_OPS_FL_REMOVING;
2890 /* The trampoline logic checks the old hashes */
2891 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2892 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2894 ftrace_run_update_code(command);
2897 * If there's no more ops registered with ftrace, run a
2898 * sanity check to make sure all rec flags are cleared.
2900 if (rcu_dereference_protected(ftrace_ops_list,
2901 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
2902 struct ftrace_page *pg;
2903 struct dyn_ftrace *rec;
2905 do_for_each_ftrace_rec(pg, rec) {
2906 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
2907 pr_warn(" %pS flags:%lx\n",
2908 (void *)rec->ip, rec->flags);
2909 } while_for_each_ftrace_rec();
2912 ops->old_hash.filter_hash = NULL;
2913 ops->old_hash.notrace_hash = NULL;
2916 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2919 * Dynamic ops may be freed, we must make sure that all
2920 * callers are done before leaving this function.
2921 * The same goes for freeing the per_cpu data of the per_cpu
2924 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU)) {
2926 * We need to do a hard force of sched synchronization.
2927 * This is because we use preempt_disable() to do RCU, but
2928 * the function tracers can be called where RCU is not watching
2929 * (like before user_exit()). We can not rely on the RCU
2930 * infrastructure to do the synchronization, thus we must do it
2933 schedule_on_each_cpu(ftrace_sync);
2936 * When the kernel is preeptive, tasks can be preempted
2937 * while on a ftrace trampoline. Just scheduling a task on
2938 * a CPU is not good enough to flush them. Calling
2939 * synchornize_rcu_tasks() will wait for those tasks to
2940 * execute and either schedule voluntarily or enter user space.
2942 if (IS_ENABLED(CONFIG_PREEMPT))
2943 synchronize_rcu_tasks();
2946 arch_ftrace_trampoline_free(ops);
2948 if (ops->flags & FTRACE_OPS_FL_PER_CPU)
2949 per_cpu_ops_free(ops);
2955 static void ftrace_startup_sysctl(void)
2959 if (unlikely(ftrace_disabled))
2962 /* Force update next time */
2963 saved_ftrace_func = NULL;
2964 /* ftrace_start_up is true if we want ftrace running */
2965 if (ftrace_start_up) {
2966 command = FTRACE_UPDATE_CALLS;
2967 if (ftrace_graph_active)
2968 command |= FTRACE_START_FUNC_RET;
2969 ftrace_startup_enable(command);
2973 static void ftrace_shutdown_sysctl(void)
2977 if (unlikely(ftrace_disabled))
2980 /* ftrace_start_up is true if ftrace is running */
2981 if (ftrace_start_up) {
2982 command = FTRACE_DISABLE_CALLS;
2983 if (ftrace_graph_active)
2984 command |= FTRACE_STOP_FUNC_RET;
2985 ftrace_run_update_code(command);
2989 static u64 ftrace_update_time;
2990 unsigned long ftrace_update_tot_cnt;
2992 static inline int ops_traces_mod(struct ftrace_ops *ops)
2995 * Filter_hash being empty will default to trace module.
2996 * But notrace hash requires a test of individual module functions.
2998 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
2999 ftrace_hash_empty(ops->func_hash->notrace_hash);
3003 * Check if the current ops references the record.
3005 * If the ops traces all functions, then it was already accounted for.
3006 * If the ops does not trace the current record function, skip it.
3007 * If the ops ignores the function via notrace filter, skip it.
3010 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3012 /* If ops isn't enabled, ignore it */
3013 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
3016 /* If ops traces all then it includes this function */
3017 if (ops_traces_mod(ops))
3020 /* The function must be in the filter */
3021 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
3022 !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
3025 /* If in notrace hash, we ignore it too */
3026 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
3032 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
3034 struct ftrace_page *pg;
3035 struct dyn_ftrace *p;
3037 unsigned long update_cnt = 0;
3038 unsigned long rec_flags = 0;
3041 start = ftrace_now(raw_smp_processor_id());
3044 * When a module is loaded, this function is called to convert
3045 * the calls to mcount in its text to nops, and also to create
3046 * an entry in the ftrace data. Now, if ftrace is activated
3047 * after this call, but before the module sets its text to
3048 * read-only, the modification of enabling ftrace can fail if
3049 * the read-only is done while ftrace is converting the calls.
3050 * To prevent this, the module's records are set as disabled
3051 * and will be enabled after the call to set the module's text
3055 rec_flags |= FTRACE_FL_DISABLED;
3057 for (pg = new_pgs; pg; pg = pg->next) {
3059 for (i = 0; i < pg->index; i++) {
3061 /* If something went wrong, bail without enabling anything */
3062 if (unlikely(ftrace_disabled))
3065 p = &pg->records[i];
3066 p->flags = rec_flags;
3069 * Do the initial record conversion from mcount jump
3070 * to the NOP instructions.
3072 if (!ftrace_code_disable(mod, p))
3079 stop = ftrace_now(raw_smp_processor_id());
3080 ftrace_update_time = stop - start;
3081 ftrace_update_tot_cnt += update_cnt;
3086 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3091 if (WARN_ON(!count))
3094 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
3097 * We want to fill as much as possible. No more than a page
3100 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
3104 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3107 /* if we can't allocate this size, try something smaller */
3114 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3123 static struct ftrace_page *
3124 ftrace_allocate_pages(unsigned long num_to_init)
3126 struct ftrace_page *start_pg;
3127 struct ftrace_page *pg;
3134 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3139 * Try to allocate as much as possible in one continues
3140 * location that fills in all of the space. We want to
3141 * waste as little space as possible.
3144 cnt = ftrace_allocate_records(pg, num_to_init);
3152 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3164 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3165 free_pages((unsigned long)pg->records, order);
3166 start_pg = pg->next;
3170 pr_info("ftrace: FAILED to allocate memory for functions\n");
3174 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3176 struct ftrace_iterator {
3180 struct ftrace_page *pg;
3181 struct dyn_ftrace *func;
3182 struct ftrace_func_probe *probe;
3183 struct ftrace_func_entry *probe_entry;
3184 struct trace_parser parser;
3185 struct ftrace_hash *hash;
3186 struct ftrace_ops *ops;
3187 struct trace_array *tr;
3188 struct list_head *mod_list;
3195 t_probe_next(struct seq_file *m, loff_t *pos)
3197 struct ftrace_iterator *iter = m->private;
3198 struct trace_array *tr = iter->ops->private;
3199 struct list_head *func_probes;
3200 struct ftrace_hash *hash;
3201 struct list_head *next;
3202 struct hlist_node *hnd = NULL;
3203 struct hlist_head *hhd;
3212 func_probes = &tr->func_probes;
3213 if (list_empty(func_probes))
3217 next = func_probes->next;
3218 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3221 if (iter->probe_entry)
3222 hnd = &iter->probe_entry->hlist;
3224 hash = iter->probe->ops.func_hash->filter_hash;
3227 * A probe being registered may temporarily have an empty hash
3228 * and it's at the end of the func_probes list.
3230 if (!hash || hash == EMPTY_HASH)
3233 size = 1 << hash->size_bits;
3236 if (iter->pidx >= size) {
3237 if (iter->probe->list.next == func_probes)
3239 next = iter->probe->list.next;
3240 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3241 hash = iter->probe->ops.func_hash->filter_hash;
3242 size = 1 << hash->size_bits;
3246 hhd = &hash->buckets[iter->pidx];
3248 if (hlist_empty(hhd)) {
3264 if (WARN_ON_ONCE(!hnd))
3267 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3272 static void *t_probe_start(struct seq_file *m, loff_t *pos)
3274 struct ftrace_iterator *iter = m->private;
3278 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3281 if (iter->mod_pos > *pos)
3285 iter->probe_entry = NULL;
3287 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3288 p = t_probe_next(m, &l);
3295 /* Only set this if we have an item */
3296 iter->flags |= FTRACE_ITER_PROBE;
3302 t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3304 struct ftrace_func_entry *probe_entry;
3305 struct ftrace_probe_ops *probe_ops;
3306 struct ftrace_func_probe *probe;
3308 probe = iter->probe;
3309 probe_entry = iter->probe_entry;
3311 if (WARN_ON_ONCE(!probe || !probe_entry))
3314 probe_ops = probe->probe_ops;
3316 if (probe_ops->print)
3317 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3319 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3320 (void *)probe_ops->func);
3326 t_mod_next(struct seq_file *m, loff_t *pos)
3328 struct ftrace_iterator *iter = m->private;
3329 struct trace_array *tr = iter->tr;
3334 iter->mod_list = iter->mod_list->next;
3336 if (iter->mod_list == &tr->mod_trace ||
3337 iter->mod_list == &tr->mod_notrace) {
3338 iter->flags &= ~FTRACE_ITER_MOD;
3342 iter->mod_pos = *pos;
3347 static void *t_mod_start(struct seq_file *m, loff_t *pos)
3349 struct ftrace_iterator *iter = m->private;
3353 if (iter->func_pos > *pos)
3356 iter->mod_pos = iter->func_pos;
3358 /* probes are only available if tr is set */
3362 for (l = 0; l <= (*pos - iter->func_pos); ) {
3363 p = t_mod_next(m, &l);
3368 iter->flags &= ~FTRACE_ITER_MOD;
3369 return t_probe_start(m, pos);
3372 /* Only set this if we have an item */
3373 iter->flags |= FTRACE_ITER_MOD;
3379 t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3381 struct ftrace_mod_load *ftrace_mod;
3382 struct trace_array *tr = iter->tr;
3384 if (WARN_ON_ONCE(!iter->mod_list) ||
3385 iter->mod_list == &tr->mod_trace ||
3386 iter->mod_list == &tr->mod_notrace)
3389 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3391 if (ftrace_mod->func)
3392 seq_printf(m, "%s", ftrace_mod->func);
3396 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3402 t_func_next(struct seq_file *m, loff_t *pos)
3404 struct ftrace_iterator *iter = m->private;
3405 struct dyn_ftrace *rec = NULL;
3410 if (iter->idx >= iter->pg->index) {
3411 if (iter->pg->next) {
3412 iter->pg = iter->pg->next;
3417 rec = &iter->pg->records[iter->idx++];
3418 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3419 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3421 ((iter->flags & FTRACE_ITER_ENABLED) &&
3422 !(rec->flags & FTRACE_FL_ENABLED))) {
3432 iter->pos = iter->func_pos = *pos;
3439 t_next(struct seq_file *m, void *v, loff_t *pos)
3441 struct ftrace_iterator *iter = m->private;
3442 loff_t l = *pos; /* t_probe_start() must use original pos */
3445 if (unlikely(ftrace_disabled))
3448 if (iter->flags & FTRACE_ITER_PROBE)
3449 return t_probe_next(m, pos);
3451 if (iter->flags & FTRACE_ITER_MOD)
3452 return t_mod_next(m, pos);
3454 if (iter->flags & FTRACE_ITER_PRINTALL) {
3455 /* next must increment pos, and t_probe_start does not */
3457 return t_mod_start(m, &l);
3460 ret = t_func_next(m, pos);
3463 return t_mod_start(m, &l);
3468 static void reset_iter_read(struct ftrace_iterator *iter)
3472 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3475 static void *t_start(struct seq_file *m, loff_t *pos)
3477 struct ftrace_iterator *iter = m->private;
3481 mutex_lock(&ftrace_lock);
3483 if (unlikely(ftrace_disabled))
3487 * If an lseek was done, then reset and start from beginning.
3489 if (*pos < iter->pos)
3490 reset_iter_read(iter);
3493 * For set_ftrace_filter reading, if we have the filter
3494 * off, we can short cut and just print out that all
3495 * functions are enabled.
3497 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3498 ftrace_hash_empty(iter->hash)) {
3499 iter->func_pos = 1; /* Account for the message */
3501 return t_mod_start(m, pos);
3502 iter->flags |= FTRACE_ITER_PRINTALL;
3503 /* reset in case of seek/pread */
3504 iter->flags &= ~FTRACE_ITER_PROBE;
3508 if (iter->flags & FTRACE_ITER_MOD)
3509 return t_mod_start(m, pos);
3512 * Unfortunately, we need to restart at ftrace_pages_start
3513 * every time we let go of the ftrace_mutex. This is because
3514 * those pointers can change without the lock.
3516 iter->pg = ftrace_pages_start;
3518 for (l = 0; l <= *pos; ) {
3519 p = t_func_next(m, &l);
3525 return t_mod_start(m, pos);
3530 static void t_stop(struct seq_file *m, void *p)
3532 mutex_unlock(&ftrace_lock);
3536 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3541 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3542 struct dyn_ftrace *rec)
3546 ptr = arch_ftrace_trampoline_func(ops, rec);
3548 seq_printf(m, " ->%pS", ptr);
3551 static int t_show(struct seq_file *m, void *v)
3553 struct ftrace_iterator *iter = m->private;
3554 struct dyn_ftrace *rec;
3556 if (iter->flags & FTRACE_ITER_PROBE)
3557 return t_probe_show(m, iter);
3559 if (iter->flags & FTRACE_ITER_MOD)
3560 return t_mod_show(m, iter);
3562 if (iter->flags & FTRACE_ITER_PRINTALL) {
3563 if (iter->flags & FTRACE_ITER_NOTRACE)
3564 seq_puts(m, "#### no functions disabled ####\n");
3566 seq_puts(m, "#### all functions enabled ####\n");
3575 seq_printf(m, "%ps", (void *)rec->ip);
3576 if (iter->flags & FTRACE_ITER_ENABLED) {
3577 struct ftrace_ops *ops;
3579 seq_printf(m, " (%ld)%s%s",
3580 ftrace_rec_count(rec),
3581 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3582 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ");
3583 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3584 ops = ftrace_find_tramp_ops_any(rec);
3587 seq_printf(m, "\ttramp: %pS (%pS)",
3588 (void *)ops->trampoline,
3590 add_trampoline_func(m, ops, rec);
3591 ops = ftrace_find_tramp_ops_next(rec, ops);
3594 seq_puts(m, "\ttramp: ERROR!");
3596 add_trampoline_func(m, NULL, rec);
3605 static const struct seq_operations show_ftrace_seq_ops = {
3613 ftrace_avail_open(struct inode *inode, struct file *file)
3615 struct ftrace_iterator *iter;
3617 if (unlikely(ftrace_disabled))
3620 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3624 iter->pg = ftrace_pages_start;
3625 iter->ops = &global_ops;
3631 ftrace_enabled_open(struct inode *inode, struct file *file)
3633 struct ftrace_iterator *iter;
3635 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3639 iter->pg = ftrace_pages_start;
3640 iter->flags = FTRACE_ITER_ENABLED;
3641 iter->ops = &global_ops;
3647 * ftrace_regex_open - initialize function tracer filter files
3648 * @ops: The ftrace_ops that hold the hash filters
3649 * @flag: The type of filter to process
3650 * @inode: The inode, usually passed in to your open routine
3651 * @file: The file, usually passed in to your open routine
3653 * ftrace_regex_open() initializes the filter files for the
3654 * @ops. Depending on @flag it may process the filter hash or
3655 * the notrace hash of @ops. With this called from the open
3656 * routine, you can use ftrace_filter_write() for the write
3657 * routine if @flag has FTRACE_ITER_FILTER set, or
3658 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3659 * tracing_lseek() should be used as the lseek routine, and
3660 * release must call ftrace_regex_release().
3663 ftrace_regex_open(struct ftrace_ops *ops, int flag,
3664 struct inode *inode, struct file *file)
3666 struct ftrace_iterator *iter;
3667 struct ftrace_hash *hash;
3668 struct list_head *mod_head;
3669 struct trace_array *tr = ops->private;
3672 ftrace_ops_init(ops);
3674 if (unlikely(ftrace_disabled))
3677 if (tr && trace_array_get(tr) < 0)
3680 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3684 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
3691 mutex_lock(&ops->func_hash->regex_lock);
3693 if (flag & FTRACE_ITER_NOTRACE) {
3694 hash = ops->func_hash->notrace_hash;
3695 mod_head = tr ? &tr->mod_notrace : NULL;
3697 hash = ops->func_hash->filter_hash;
3698 mod_head = tr ? &tr->mod_trace : NULL;
3701 iter->mod_list = mod_head;
3703 if (file->f_mode & FMODE_WRITE) {
3704 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3706 if (file->f_flags & O_TRUNC) {
3707 iter->hash = alloc_ftrace_hash(size_bits);
3708 clear_ftrace_mod_list(mod_head);
3710 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3714 trace_parser_put(&iter->parser);
3722 if (file->f_mode & FMODE_READ) {
3723 iter->pg = ftrace_pages_start;
3725 ret = seq_open(file, &show_ftrace_seq_ops);
3727 struct seq_file *m = file->private_data;
3731 free_ftrace_hash(iter->hash);
3732 trace_parser_put(&iter->parser);
3735 file->private_data = iter;
3738 mutex_unlock(&ops->func_hash->regex_lock);
3744 trace_array_put(tr);
3751 ftrace_filter_open(struct inode *inode, struct file *file)
3753 struct ftrace_ops *ops = inode->i_private;
3755 return ftrace_regex_open(ops,
3756 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3761 ftrace_notrace_open(struct inode *inode, struct file *file)
3763 struct ftrace_ops *ops = inode->i_private;
3765 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3769 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3770 struct ftrace_glob {
3777 * If symbols in an architecture don't correspond exactly to the user-visible
3778 * name of what they represent, it is possible to define this function to
3779 * perform the necessary adjustments.
3781 char * __weak arch_ftrace_match_adjust(char *str, const char *search)
3786 static int ftrace_match(char *str, struct ftrace_glob *g)
3791 str = arch_ftrace_match_adjust(str, g->search);
3795 if (strcmp(str, g->search) == 0)
3798 case MATCH_FRONT_ONLY:
3799 if (strncmp(str, g->search, g->len) == 0)
3802 case MATCH_MIDDLE_ONLY:
3803 if (strstr(str, g->search))
3806 case MATCH_END_ONLY:
3808 if (slen >= g->len &&
3809 memcmp(str + slen - g->len, g->search, g->len) == 0)
3813 if (glob_match(g->search, str))
3822 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3824 struct ftrace_func_entry *entry;
3827 entry = ftrace_lookup_ip(hash, rec->ip);
3829 /* Do nothing if it doesn't exist */
3833 free_hash_entry(hash, entry);
3835 /* Do nothing if it exists */
3839 ret = add_hash_entry(hash, rec->ip);
3845 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3846 struct ftrace_glob *mod_g, int exclude_mod)
3848 char str[KSYM_SYMBOL_LEN];
3851 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3854 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3856 /* blank module name to match all modules */
3858 /* blank module globbing: modname xor exclude_mod */
3859 if (!exclude_mod != !modname)
3865 * exclude_mod is set to trace everything but the given
3866 * module. If it is set and the module matches, then
3867 * return 0. If it is not set, and the module doesn't match
3868 * also return 0. Otherwise, check the function to see if
3871 if (!mod_matches == !exclude_mod)
3874 /* blank search means to match all funcs in the mod */
3879 return ftrace_match(str, func_g);
3883 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
3885 struct ftrace_page *pg;
3886 struct dyn_ftrace *rec;
3887 struct ftrace_glob func_g = { .type = MATCH_FULL };
3888 struct ftrace_glob mod_g = { .type = MATCH_FULL };
3889 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
3890 int exclude_mod = 0;
3893 int clear_filter = 0;
3896 func_g.type = filter_parse_regex(func, len, &func_g.search,
3898 func_g.len = strlen(func_g.search);
3902 mod_g.type = filter_parse_regex(mod, strlen(mod),
3903 &mod_g.search, &exclude_mod);
3904 mod_g.len = strlen(mod_g.search);
3907 mutex_lock(&ftrace_lock);
3909 if (unlikely(ftrace_disabled))
3912 do_for_each_ftrace_rec(pg, rec) {
3914 if (rec->flags & FTRACE_FL_DISABLED)
3917 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
3918 ret = enter_record(hash, rec, clear_filter);
3925 } while_for_each_ftrace_rec();
3927 mutex_unlock(&ftrace_lock);
3933 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
3935 return match_records(hash, buff, len, NULL);
3938 static void ftrace_ops_update_code(struct ftrace_ops *ops,
3939 struct ftrace_ops_hash *old_hash)
3941 struct ftrace_ops *op;
3943 if (!ftrace_enabled)
3946 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
3947 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
3952 * If this is the shared global_ops filter, then we need to
3953 * check if there is another ops that shares it, is enabled.
3954 * If so, we still need to run the modify code.
3956 if (ops->func_hash != &global_ops.local_hash)
3959 do_for_each_ftrace_op(op, ftrace_ops_list) {
3960 if (op->func_hash == &global_ops.local_hash &&
3961 op->flags & FTRACE_OPS_FL_ENABLED) {
3962 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
3963 /* Only need to do this once */
3966 } while_for_each_ftrace_op(op);
3969 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
3970 struct ftrace_hash **orig_hash,
3971 struct ftrace_hash *hash,
3974 struct ftrace_ops_hash old_hash_ops;
3975 struct ftrace_hash *old_hash;
3978 old_hash = *orig_hash;
3979 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
3980 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
3981 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3983 ftrace_ops_update_code(ops, &old_hash_ops);
3984 free_ftrace_hash_rcu(old_hash);
3989 static bool module_exists(const char *module)
3991 /* All modules have the symbol __this_module */
3992 const char this_mod[] = "__this_module";
3993 const int modname_size = MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 1;
3994 char modname[modname_size + 1];
3998 n = snprintf(modname, modname_size + 1, "%s:%s", module, this_mod);
4000 if (n > modname_size)
4003 val = module_kallsyms_lookup_name(modname);
4007 static int cache_mod(struct trace_array *tr,
4008 const char *func, char *module, int enable)
4010 struct ftrace_mod_load *ftrace_mod, *n;
4011 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4014 mutex_lock(&ftrace_lock);
4016 /* We do not cache inverse filters */
4017 if (func[0] == '!') {
4021 /* Look to remove this hash */
4022 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4023 if (strcmp(ftrace_mod->module, module) != 0)
4026 /* no func matches all */
4027 if (strcmp(func, "*") == 0 ||
4028 (ftrace_mod->func &&
4029 strcmp(ftrace_mod->func, func) == 0)) {
4031 free_ftrace_mod(ftrace_mod);
4039 /* We only care about modules that have not been loaded yet */
4040 if (module_exists(module))
4043 /* Save this string off, and execute it when the module is loaded */
4044 ret = ftrace_add_mod(tr, func, module, enable);
4046 mutex_unlock(&ftrace_lock);
4052 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4053 int reset, int enable);
4055 #ifdef CONFIG_MODULES
4056 static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4057 char *mod, bool enable)
4059 struct ftrace_mod_load *ftrace_mod, *n;
4060 struct ftrace_hash **orig_hash, *new_hash;
4061 LIST_HEAD(process_mods);
4065 mutex_lock(&ops->func_hash->regex_lock);
4068 orig_hash = &ops->func_hash->filter_hash;
4070 orig_hash = &ops->func_hash->notrace_hash;
4072 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4075 goto out; /* warn? */
4077 mutex_lock(&ftrace_lock);
4079 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4081 if (strcmp(ftrace_mod->module, mod) != 0)
4084 if (ftrace_mod->func)
4085 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4087 func = kstrdup("*", GFP_KERNEL);
4089 if (!func) /* warn? */
4092 list_del(&ftrace_mod->list);
4093 list_add(&ftrace_mod->list, &process_mods);
4095 /* Use the newly allocated func, as it may be "*" */
4096 kfree(ftrace_mod->func);
4097 ftrace_mod->func = func;
4100 mutex_unlock(&ftrace_lock);
4102 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4104 func = ftrace_mod->func;
4106 /* Grabs ftrace_lock, which is why we have this extra step */
4107 match_records(new_hash, func, strlen(func), mod);
4108 free_ftrace_mod(ftrace_mod);
4111 if (enable && list_empty(head))
4112 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4114 mutex_lock(&ftrace_lock);
4116 ret = ftrace_hash_move_and_update_ops(ops, orig_hash,
4118 mutex_unlock(&ftrace_lock);
4121 mutex_unlock(&ops->func_hash->regex_lock);
4123 free_ftrace_hash(new_hash);
4126 static void process_cached_mods(const char *mod_name)
4128 struct trace_array *tr;
4131 mod = kstrdup(mod_name, GFP_KERNEL);
4135 mutex_lock(&trace_types_lock);
4136 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4137 if (!list_empty(&tr->mod_trace))
4138 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4139 if (!list_empty(&tr->mod_notrace))
4140 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4142 mutex_unlock(&trace_types_lock);
4149 * We register the module command as a template to show others how
4150 * to register the a command as well.
4154 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4155 char *func_orig, char *cmd, char *module, int enable)
4160 /* match_records() modifies func, and we need the original */
4161 func = kstrdup(func_orig, GFP_KERNEL);
4166 * cmd == 'mod' because we only registered this func
4167 * for the 'mod' ftrace_func_command.
4168 * But if you register one func with multiple commands,
4169 * you can tell which command was used by the cmd
4172 ret = match_records(hash, func, strlen(func), module);
4176 return cache_mod(tr, func_orig, module, enable);
4182 static struct ftrace_func_command ftrace_mod_cmd = {
4184 .func = ftrace_mod_callback,
4187 static int __init ftrace_mod_cmd_init(void)
4189 return register_ftrace_command(&ftrace_mod_cmd);
4191 core_initcall(ftrace_mod_cmd_init);
4193 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4194 struct ftrace_ops *op, struct pt_regs *pt_regs)
4196 struct ftrace_probe_ops *probe_ops;
4197 struct ftrace_func_probe *probe;
4199 probe = container_of(op, struct ftrace_func_probe, ops);
4200 probe_ops = probe->probe_ops;
4203 * Disable preemption for these calls to prevent a RCU grace
4204 * period. This syncs the hash iteration and freeing of items
4205 * on the hash. rcu_read_lock is too dangerous here.
4207 preempt_disable_notrace();
4208 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4209 preempt_enable_notrace();
4212 struct ftrace_func_map {
4213 struct ftrace_func_entry entry;
4217 struct ftrace_func_mapper {
4218 struct ftrace_hash hash;
4222 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4224 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4226 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4228 struct ftrace_hash *hash;
4231 * The mapper is simply a ftrace_hash, but since the entries
4232 * in the hash are not ftrace_func_entry type, we define it
4233 * as a separate structure.
4235 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4236 return (struct ftrace_func_mapper *)hash;
4240 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4241 * @mapper: The mapper that has the ip maps
4242 * @ip: the instruction pointer to find the data for
4244 * Returns the data mapped to @ip if found otherwise NULL. The return
4245 * is actually the address of the mapper data pointer. The address is
4246 * returned for use cases where the data is no bigger than a long, and
4247 * the user can use the data pointer as its data instead of having to
4248 * allocate more memory for the reference.
4250 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4253 struct ftrace_func_entry *entry;
4254 struct ftrace_func_map *map;
4256 entry = ftrace_lookup_ip(&mapper->hash, ip);
4260 map = (struct ftrace_func_map *)entry;
4265 * ftrace_func_mapper_add_ip - Map some data to an ip
4266 * @mapper: The mapper that has the ip maps
4267 * @ip: The instruction pointer address to map @data to
4268 * @data: The data to map to @ip
4270 * Returns 0 on succes otherwise an error.
4272 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4273 unsigned long ip, void *data)
4275 struct ftrace_func_entry *entry;
4276 struct ftrace_func_map *map;
4278 entry = ftrace_lookup_ip(&mapper->hash, ip);
4282 map = kmalloc(sizeof(*map), GFP_KERNEL);
4289 __add_hash_entry(&mapper->hash, &map->entry);
4295 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4296 * @mapper: The mapper that has the ip maps
4297 * @ip: The instruction pointer address to remove the data from
4299 * Returns the data if it is found, otherwise NULL.
4300 * Note, if the data pointer is used as the data itself, (see
4301 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4302 * if the data pointer was set to zero.
4304 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4307 struct ftrace_func_entry *entry;
4308 struct ftrace_func_map *map;
4311 entry = ftrace_lookup_ip(&mapper->hash, ip);
4315 map = (struct ftrace_func_map *)entry;
4318 remove_hash_entry(&mapper->hash, entry);
4325 * free_ftrace_func_mapper - free a mapping of ips and data
4326 * @mapper: The mapper that has the ip maps
4327 * @free_func: A function to be called on each data item.
4329 * This is used to free the function mapper. The @free_func is optional
4330 * and can be used if the data needs to be freed as well.
4332 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4333 ftrace_mapper_func free_func)
4335 struct ftrace_func_entry *entry;
4336 struct ftrace_func_map *map;
4337 struct hlist_head *hhd;
4343 if (free_func && mapper->hash.count) {
4344 size = 1 << mapper->hash.size_bits;
4345 for (i = 0; i < size; i++) {
4346 hhd = &mapper->hash.buckets[i];
4347 hlist_for_each_entry(entry, hhd, hlist) {
4348 map = (struct ftrace_func_map *)entry;
4353 free_ftrace_hash(&mapper->hash);
4356 static void release_probe(struct ftrace_func_probe *probe)
4358 struct ftrace_probe_ops *probe_ops;
4360 mutex_lock(&ftrace_lock);
4362 WARN_ON(probe->ref <= 0);
4364 /* Subtract the ref that was used to protect this instance */
4368 probe_ops = probe->probe_ops;
4370 * Sending zero as ip tells probe_ops to free
4371 * the probe->data itself
4373 if (probe_ops->free)
4374 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4375 list_del(&probe->list);
4378 mutex_unlock(&ftrace_lock);
4381 static void acquire_probe_locked(struct ftrace_func_probe *probe)
4384 * Add one ref to keep it from being freed when releasing the
4385 * ftrace_lock mutex.
4391 register_ftrace_function_probe(char *glob, struct trace_array *tr,
4392 struct ftrace_probe_ops *probe_ops,
4395 struct ftrace_func_entry *entry;
4396 struct ftrace_func_probe *probe;
4397 struct ftrace_hash **orig_hash;
4398 struct ftrace_hash *old_hash;
4399 struct ftrace_hash *hash;
4408 /* We do not support '!' for function probes */
4409 if (WARN_ON(glob[0] == '!'))
4413 mutex_lock(&ftrace_lock);
4414 /* Check if the probe_ops is already registered */
4415 list_for_each_entry(probe, &tr->func_probes, list) {
4416 if (probe->probe_ops == probe_ops)
4419 if (&probe->list == &tr->func_probes) {
4420 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4422 mutex_unlock(&ftrace_lock);
4425 probe->probe_ops = probe_ops;
4426 probe->ops.func = function_trace_probe_call;
4428 ftrace_ops_init(&probe->ops);
4429 list_add(&probe->list, &tr->func_probes);
4432 acquire_probe_locked(probe);
4434 mutex_unlock(&ftrace_lock);
4437 * Note, there's a small window here that the func_hash->filter_hash
4438 * may be NULL or empty. Need to be carefule when reading the loop.
4440 mutex_lock(&probe->ops.func_hash->regex_lock);
4442 orig_hash = &probe->ops.func_hash->filter_hash;
4443 old_hash = *orig_hash;
4444 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4451 ret = ftrace_match_records(hash, glob, strlen(glob));
4453 /* Nothing found? */
4460 size = 1 << hash->size_bits;
4461 for (i = 0; i < size; i++) {
4462 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4463 if (ftrace_lookup_ip(old_hash, entry->ip))
4466 * The caller might want to do something special
4467 * for each function we find. We call the callback
4468 * to give the caller an opportunity to do so.
4470 if (probe_ops->init) {
4471 ret = probe_ops->init(probe_ops, tr,
4475 if (probe_ops->free && count)
4476 probe_ops->free(probe_ops, tr,
4486 mutex_lock(&ftrace_lock);
4489 /* Nothing was added? */
4494 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4499 /* One ref for each new function traced */
4500 probe->ref += count;
4502 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4503 ret = ftrace_startup(&probe->ops, 0);
4506 mutex_unlock(&ftrace_lock);
4511 mutex_unlock(&probe->ops.func_hash->regex_lock);
4512 free_ftrace_hash(hash);
4514 release_probe(probe);
4519 if (!probe_ops->free || !count)
4522 /* Failed to do the move, need to call the free functions */
4523 for (i = 0; i < size; i++) {
4524 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4525 if (ftrace_lookup_ip(old_hash, entry->ip))
4527 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4534 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4535 struct ftrace_probe_ops *probe_ops)
4537 struct ftrace_ops_hash old_hash_ops;
4538 struct ftrace_func_entry *entry;
4539 struct ftrace_func_probe *probe;
4540 struct ftrace_glob func_g;
4541 struct ftrace_hash **orig_hash;
4542 struct ftrace_hash *old_hash;
4543 struct ftrace_hash *hash = NULL;
4544 struct hlist_node *tmp;
4545 struct hlist_head hhd;
4546 char str[KSYM_SYMBOL_LEN];
4548 int i, ret = -ENODEV;
4551 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4552 func_g.search = NULL;
4556 func_g.type = filter_parse_regex(glob, strlen(glob),
4557 &func_g.search, ¬);
4558 func_g.len = strlen(func_g.search);
4560 /* we do not support '!' for function probes */
4565 mutex_lock(&ftrace_lock);
4566 /* Check if the probe_ops is already registered */
4567 list_for_each_entry(probe, &tr->func_probes, list) {
4568 if (probe->probe_ops == probe_ops)
4571 if (&probe->list == &tr->func_probes)
4572 goto err_unlock_ftrace;
4575 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4576 goto err_unlock_ftrace;
4578 acquire_probe_locked(probe);
4580 mutex_unlock(&ftrace_lock);
4582 mutex_lock(&probe->ops.func_hash->regex_lock);
4584 orig_hash = &probe->ops.func_hash->filter_hash;
4585 old_hash = *orig_hash;
4587 if (ftrace_hash_empty(old_hash))
4590 old_hash_ops.filter_hash = old_hash;
4591 /* Probes only have filters */
4592 old_hash_ops.notrace_hash = NULL;
4595 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4599 INIT_HLIST_HEAD(&hhd);
4601 size = 1 << hash->size_bits;
4602 for (i = 0; i < size; i++) {
4603 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4605 if (func_g.search) {
4606 kallsyms_lookup(entry->ip, NULL, NULL,
4608 if (!ftrace_match(str, &func_g))
4612 remove_hash_entry(hash, entry);
4613 hlist_add_head(&entry->hlist, &hhd);
4617 /* Nothing found? */
4623 mutex_lock(&ftrace_lock);
4625 WARN_ON(probe->ref < count);
4627 probe->ref -= count;
4629 if (ftrace_hash_empty(hash))
4630 ftrace_shutdown(&probe->ops, 0);
4632 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4635 /* still need to update the function call sites */
4636 if (ftrace_enabled && !ftrace_hash_empty(hash))
4637 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4639 synchronize_sched();
4641 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4642 hlist_del(&entry->hlist);
4643 if (probe_ops->free)
4644 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4647 mutex_unlock(&ftrace_lock);
4650 mutex_unlock(&probe->ops.func_hash->regex_lock);
4651 free_ftrace_hash(hash);
4653 release_probe(probe);
4658 mutex_unlock(&ftrace_lock);
4662 void clear_ftrace_function_probes(struct trace_array *tr)
4664 struct ftrace_func_probe *probe, *n;
4666 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4667 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
4670 static LIST_HEAD(ftrace_commands);
4671 static DEFINE_MUTEX(ftrace_cmd_mutex);
4674 * Currently we only register ftrace commands from __init, so mark this
4677 __init int register_ftrace_command(struct ftrace_func_command *cmd)
4679 struct ftrace_func_command *p;
4682 mutex_lock(&ftrace_cmd_mutex);
4683 list_for_each_entry(p, &ftrace_commands, list) {
4684 if (strcmp(cmd->name, p->name) == 0) {
4689 list_add(&cmd->list, &ftrace_commands);
4691 mutex_unlock(&ftrace_cmd_mutex);
4697 * Currently we only unregister ftrace commands from __init, so mark
4700 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4702 struct ftrace_func_command *p, *n;
4705 mutex_lock(&ftrace_cmd_mutex);
4706 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4707 if (strcmp(cmd->name, p->name) == 0) {
4709 list_del_init(&p->list);
4714 mutex_unlock(&ftrace_cmd_mutex);
4719 static int ftrace_process_regex(struct ftrace_iterator *iter,
4720 char *buff, int len, int enable)
4722 struct ftrace_hash *hash = iter->hash;
4723 struct trace_array *tr = iter->ops->private;
4724 char *func, *command, *next = buff;
4725 struct ftrace_func_command *p;
4728 func = strsep(&next, ":");
4731 ret = ftrace_match_records(hash, func, len);
4741 command = strsep(&next, ":");
4743 mutex_lock(&ftrace_cmd_mutex);
4744 list_for_each_entry(p, &ftrace_commands, list) {
4745 if (strcmp(p->name, command) == 0) {
4746 ret = p->func(tr, hash, func, command, next, enable);
4751 mutex_unlock(&ftrace_cmd_mutex);
4757 ftrace_regex_write(struct file *file, const char __user *ubuf,
4758 size_t cnt, loff_t *ppos, int enable)
4760 struct ftrace_iterator *iter;
4761 struct trace_parser *parser;
4767 if (file->f_mode & FMODE_READ) {
4768 struct seq_file *m = file->private_data;
4771 iter = file->private_data;
4773 if (unlikely(ftrace_disabled))
4776 /* iter->hash is a local copy, so we don't need regex_lock */
4778 parser = &iter->parser;
4779 read = trace_get_user(parser, ubuf, cnt, ppos);
4781 if (read >= 0 && trace_parser_loaded(parser) &&
4782 !trace_parser_cont(parser)) {
4783 ret = ftrace_process_regex(iter, parser->buffer,
4784 parser->idx, enable);
4785 trace_parser_clear(parser);
4796 ftrace_filter_write(struct file *file, const char __user *ubuf,
4797 size_t cnt, loff_t *ppos)
4799 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4803 ftrace_notrace_write(struct file *file, const char __user *ubuf,
4804 size_t cnt, loff_t *ppos)
4806 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4810 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4812 struct ftrace_func_entry *entry;
4814 if (!ftrace_location(ip))
4818 entry = ftrace_lookup_ip(hash, ip);
4821 free_hash_entry(hash, entry);
4825 return add_hash_entry(hash, ip);
4829 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4830 unsigned long ip, int remove, int reset, int enable)
4832 struct ftrace_hash **orig_hash;
4833 struct ftrace_hash *hash;
4836 if (unlikely(ftrace_disabled))
4839 mutex_lock(&ops->func_hash->regex_lock);
4842 orig_hash = &ops->func_hash->filter_hash;
4844 orig_hash = &ops->func_hash->notrace_hash;
4847 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4849 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4853 goto out_regex_unlock;
4856 if (buf && !ftrace_match_records(hash, buf, len)) {
4858 goto out_regex_unlock;
4861 ret = ftrace_match_addr(hash, ip, remove);
4863 goto out_regex_unlock;
4866 mutex_lock(&ftrace_lock);
4867 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
4868 mutex_unlock(&ftrace_lock);
4871 mutex_unlock(&ops->func_hash->regex_lock);
4873 free_ftrace_hash(hash);
4878 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
4879 int reset, int enable)
4881 return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
4885 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
4886 * @ops - the ops to set the filter with
4887 * @ip - the address to add to or remove from the filter.
4888 * @remove - non zero to remove the ip from the filter
4889 * @reset - non zero to reset all filters before applying this filter.
4891 * Filters denote which functions should be enabled when tracing is enabled
4892 * If @ip is NULL, it failes to update filter.
4894 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
4895 int remove, int reset)
4897 ftrace_ops_init(ops);
4898 return ftrace_set_addr(ops, ip, remove, reset, 1);
4900 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
4903 * ftrace_ops_set_global_filter - setup ops to use global filters
4904 * @ops - the ops which will use the global filters
4906 * ftrace users who need global function trace filtering should call this.
4907 * It can set the global filter only if ops were not initialized before.
4909 void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
4911 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
4914 ftrace_ops_init(ops);
4915 ops->func_hash = &global_ops.local_hash;
4917 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
4920 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4921 int reset, int enable)
4923 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
4927 * ftrace_set_filter - set a function to filter on in ftrace
4928 * @ops - the ops to set the filter with
4929 * @buf - the string that holds the function filter text.
4930 * @len - the length of the string.
4931 * @reset - non zero to reset all filters before applying this filter.
4933 * Filters denote which functions should be enabled when tracing is enabled.
4934 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4936 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
4939 ftrace_ops_init(ops);
4940 return ftrace_set_regex(ops, buf, len, reset, 1);
4942 EXPORT_SYMBOL_GPL(ftrace_set_filter);
4945 * ftrace_set_notrace - set a function to not trace in ftrace
4946 * @ops - the ops to set the notrace filter with
4947 * @buf - the string that holds the function notrace text.
4948 * @len - the length of the string.
4949 * @reset - non zero to reset all filters before applying this filter.
4951 * Notrace Filters denote which functions should not be enabled when tracing
4952 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4955 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
4958 ftrace_ops_init(ops);
4959 return ftrace_set_regex(ops, buf, len, reset, 0);
4961 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
4963 * ftrace_set_global_filter - set a function to filter on with global tracers
4964 * @buf - the string that holds the function filter text.
4965 * @len - the length of the string.
4966 * @reset - non zero to reset all filters before applying this filter.
4968 * Filters denote which functions should be enabled when tracing is enabled.
4969 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4971 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
4973 ftrace_set_regex(&global_ops, buf, len, reset, 1);
4975 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
4978 * ftrace_set_global_notrace - set a function to not trace with global tracers
4979 * @buf - the string that holds the function notrace text.
4980 * @len - the length of the string.
4981 * @reset - non zero to reset all filters before applying this filter.
4983 * Notrace Filters denote which functions should not be enabled when tracing
4984 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4987 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
4989 ftrace_set_regex(&global_ops, buf, len, reset, 0);
4991 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
4994 * command line interface to allow users to set filters on boot up.
4996 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
4997 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4998 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
5000 /* Used by function selftest to not test if filter is set */
5001 bool ftrace_filter_param __initdata;
5003 static int __init set_ftrace_notrace(char *str)
5005 ftrace_filter_param = true;
5006 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
5009 __setup("ftrace_notrace=", set_ftrace_notrace);
5011 static int __init set_ftrace_filter(char *str)
5013 ftrace_filter_param = true;
5014 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
5017 __setup("ftrace_filter=", set_ftrace_filter);
5019 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5020 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
5021 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5022 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
5024 static int __init set_graph_function(char *str)
5026 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
5029 __setup("ftrace_graph_filter=", set_graph_function);
5031 static int __init set_graph_notrace_function(char *str)
5033 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
5036 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
5038 static int __init set_graph_max_depth_function(char *str)
5042 fgraph_max_depth = simple_strtoul(str, NULL, 0);
5045 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
5047 static void __init set_ftrace_early_graph(char *buf, int enable)
5051 struct ftrace_hash *hash;
5053 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5058 func = strsep(&buf, ",");
5059 /* we allow only one expression at a time */
5060 ret = ftrace_graph_set_hash(hash, func);
5062 printk(KERN_DEBUG "ftrace: function %s not "
5063 "traceable\n", func);
5067 ftrace_graph_hash = hash;
5069 ftrace_graph_notrace_hash = hash;
5071 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5074 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
5078 ftrace_ops_init(ops);
5081 func = strsep(&buf, ",");
5082 ftrace_set_regex(ops, func, strlen(func), 0, enable);
5086 static void __init set_ftrace_early_filters(void)
5088 if (ftrace_filter_buf[0])
5089 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
5090 if (ftrace_notrace_buf[0])
5091 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
5092 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5093 if (ftrace_graph_buf[0])
5094 set_ftrace_early_graph(ftrace_graph_buf, 1);
5095 if (ftrace_graph_notrace_buf[0])
5096 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
5097 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5100 int ftrace_regex_release(struct inode *inode, struct file *file)
5102 struct seq_file *m = (struct seq_file *)file->private_data;
5103 struct ftrace_iterator *iter;
5104 struct ftrace_hash **orig_hash;
5105 struct trace_parser *parser;
5109 if (file->f_mode & FMODE_READ) {
5111 seq_release(inode, file);
5113 iter = file->private_data;
5115 parser = &iter->parser;
5116 if (trace_parser_loaded(parser)) {
5117 int enable = !(iter->flags & FTRACE_ITER_NOTRACE);
5119 parser->buffer[parser->idx] = 0;
5120 ftrace_process_regex(iter, parser->buffer,
5121 parser->idx, enable);
5124 trace_parser_put(parser);
5126 mutex_lock(&iter->ops->func_hash->regex_lock);
5128 if (file->f_mode & FMODE_WRITE) {
5129 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5132 orig_hash = &iter->ops->func_hash->filter_hash;
5134 if (list_empty(&iter->tr->mod_trace))
5135 iter->hash->flags &= ~FTRACE_HASH_FL_MOD;
5137 iter->hash->flags |= FTRACE_HASH_FL_MOD;
5140 orig_hash = &iter->ops->func_hash->notrace_hash;
5142 mutex_lock(&ftrace_lock);
5143 ret = ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5144 iter->hash, filter_hash);
5145 mutex_unlock(&ftrace_lock);
5147 /* For read only, the hash is the ops hash */
5151 mutex_unlock(&iter->ops->func_hash->regex_lock);
5152 free_ftrace_hash(iter->hash);
5154 trace_array_put(iter->tr);
5160 static const struct file_operations ftrace_avail_fops = {
5161 .open = ftrace_avail_open,
5163 .llseek = seq_lseek,
5164 .release = seq_release_private,
5167 static const struct file_operations ftrace_enabled_fops = {
5168 .open = ftrace_enabled_open,
5170 .llseek = seq_lseek,
5171 .release = seq_release_private,
5174 static const struct file_operations ftrace_filter_fops = {
5175 .open = ftrace_filter_open,
5177 .write = ftrace_filter_write,
5178 .llseek = tracing_lseek,
5179 .release = ftrace_regex_release,
5182 static const struct file_operations ftrace_notrace_fops = {
5183 .open = ftrace_notrace_open,
5185 .write = ftrace_notrace_write,
5186 .llseek = tracing_lseek,
5187 .release = ftrace_regex_release,
5190 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5192 static DEFINE_MUTEX(graph_lock);
5194 struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
5195 struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
5197 enum graph_filter_type {
5198 GRAPH_FILTER_NOTRACE = 0,
5199 GRAPH_FILTER_FUNCTION,
5202 #define FTRACE_GRAPH_EMPTY ((void *)1)
5204 struct ftrace_graph_data {
5205 struct ftrace_hash *hash;
5206 struct ftrace_func_entry *entry;
5207 int idx; /* for hash table iteration */
5208 enum graph_filter_type type;
5209 struct ftrace_hash *new_hash;
5210 const struct seq_operations *seq_ops;
5211 struct trace_parser parser;
5215 __g_next(struct seq_file *m, loff_t *pos)
5217 struct ftrace_graph_data *fgd = m->private;
5218 struct ftrace_func_entry *entry = fgd->entry;
5219 struct hlist_head *head;
5220 int i, idx = fgd->idx;
5222 if (*pos >= fgd->hash->count)
5226 hlist_for_each_entry_continue(entry, hlist) {
5234 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
5235 head = &fgd->hash->buckets[i];
5236 hlist_for_each_entry(entry, head, hlist) {
5246 g_next(struct seq_file *m, void *v, loff_t *pos)
5249 return __g_next(m, pos);
5252 static void *g_start(struct seq_file *m, loff_t *pos)
5254 struct ftrace_graph_data *fgd = m->private;
5256 mutex_lock(&graph_lock);
5258 if (fgd->type == GRAPH_FILTER_FUNCTION)
5259 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5260 lockdep_is_held(&graph_lock));
5262 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5263 lockdep_is_held(&graph_lock));
5265 /* Nothing, tell g_show to print all functions are enabled */
5266 if (ftrace_hash_empty(fgd->hash) && !*pos)
5267 return FTRACE_GRAPH_EMPTY;
5271 return __g_next(m, pos);
5274 static void g_stop(struct seq_file *m, void *p)
5276 mutex_unlock(&graph_lock);
5279 static int g_show(struct seq_file *m, void *v)
5281 struct ftrace_func_entry *entry = v;
5286 if (entry == FTRACE_GRAPH_EMPTY) {
5287 struct ftrace_graph_data *fgd = m->private;
5289 if (fgd->type == GRAPH_FILTER_FUNCTION)
5290 seq_puts(m, "#### all functions enabled ####\n");
5292 seq_puts(m, "#### no functions disabled ####\n");
5296 seq_printf(m, "%ps\n", (void *)entry->ip);
5301 static const struct seq_operations ftrace_graph_seq_ops = {
5309 __ftrace_graph_open(struct inode *inode, struct file *file,
5310 struct ftrace_graph_data *fgd)
5313 struct ftrace_hash *new_hash = NULL;
5315 if (file->f_mode & FMODE_WRITE) {
5316 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
5318 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
5321 if (file->f_flags & O_TRUNC)
5322 new_hash = alloc_ftrace_hash(size_bits);
5324 new_hash = alloc_and_copy_ftrace_hash(size_bits,
5332 if (file->f_mode & FMODE_READ) {
5333 ret = seq_open(file, &ftrace_graph_seq_ops);
5335 struct seq_file *m = file->private_data;
5339 free_ftrace_hash(new_hash);
5343 file->private_data = fgd;
5346 if (ret < 0 && file->f_mode & FMODE_WRITE)
5347 trace_parser_put(&fgd->parser);
5349 fgd->new_hash = new_hash;
5352 * All uses of fgd->hash must be taken with the graph_lock
5353 * held. The graph_lock is going to be released, so force
5354 * fgd->hash to be reinitialized when it is taken again.
5362 ftrace_graph_open(struct inode *inode, struct file *file)
5364 struct ftrace_graph_data *fgd;
5367 if (unlikely(ftrace_disabled))
5370 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5374 mutex_lock(&graph_lock);
5376 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5377 lockdep_is_held(&graph_lock));
5378 fgd->type = GRAPH_FILTER_FUNCTION;
5379 fgd->seq_ops = &ftrace_graph_seq_ops;
5381 ret = __ftrace_graph_open(inode, file, fgd);
5385 mutex_unlock(&graph_lock);
5390 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
5392 struct ftrace_graph_data *fgd;
5395 if (unlikely(ftrace_disabled))
5398 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5402 mutex_lock(&graph_lock);
5404 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5405 lockdep_is_held(&graph_lock));
5406 fgd->type = GRAPH_FILTER_NOTRACE;
5407 fgd->seq_ops = &ftrace_graph_seq_ops;
5409 ret = __ftrace_graph_open(inode, file, fgd);
5413 mutex_unlock(&graph_lock);
5418 ftrace_graph_release(struct inode *inode, struct file *file)
5420 struct ftrace_graph_data *fgd;
5421 struct ftrace_hash *old_hash, *new_hash;
5422 struct trace_parser *parser;
5425 if (file->f_mode & FMODE_READ) {
5426 struct seq_file *m = file->private_data;
5429 seq_release(inode, file);
5431 fgd = file->private_data;
5435 if (file->f_mode & FMODE_WRITE) {
5437 parser = &fgd->parser;
5439 if (trace_parser_loaded((parser))) {
5440 parser->buffer[parser->idx] = 0;
5441 ret = ftrace_graph_set_hash(fgd->new_hash,
5445 trace_parser_put(parser);
5447 new_hash = __ftrace_hash_move(fgd->new_hash);
5453 mutex_lock(&graph_lock);
5455 if (fgd->type == GRAPH_FILTER_FUNCTION) {
5456 old_hash = rcu_dereference_protected(ftrace_graph_hash,
5457 lockdep_is_held(&graph_lock));
5458 rcu_assign_pointer(ftrace_graph_hash, new_hash);
5460 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5461 lockdep_is_held(&graph_lock));
5462 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
5465 mutex_unlock(&graph_lock);
5468 * We need to do a hard force of sched synchronization.
5469 * This is because we use preempt_disable() to do RCU, but
5470 * the function tracers can be called where RCU is not watching
5471 * (like before user_exit()). We can not rely on the RCU
5472 * infrastructure to do the synchronization, thus we must do it
5475 schedule_on_each_cpu(ftrace_sync);
5477 free_ftrace_hash(old_hash);
5481 free_ftrace_hash(fgd->new_hash);
5488 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
5490 struct ftrace_glob func_g;
5491 struct dyn_ftrace *rec;
5492 struct ftrace_page *pg;
5493 struct ftrace_func_entry *entry;
5498 func_g.type = filter_parse_regex(buffer, strlen(buffer),
5499 &func_g.search, ¬);
5501 func_g.len = strlen(func_g.search);
5503 mutex_lock(&ftrace_lock);
5505 if (unlikely(ftrace_disabled)) {
5506 mutex_unlock(&ftrace_lock);
5510 do_for_each_ftrace_rec(pg, rec) {
5512 if (rec->flags & FTRACE_FL_DISABLED)
5515 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
5516 entry = ftrace_lookup_ip(hash, rec->ip);
5523 if (add_hash_entry(hash, rec->ip) < 0)
5527 free_hash_entry(hash, entry);
5532 } while_for_each_ftrace_rec();
5534 mutex_unlock(&ftrace_lock);
5543 ftrace_graph_write(struct file *file, const char __user *ubuf,
5544 size_t cnt, loff_t *ppos)
5546 ssize_t read, ret = 0;
5547 struct ftrace_graph_data *fgd = file->private_data;
5548 struct trace_parser *parser;
5553 /* Read mode uses seq functions */
5554 if (file->f_mode & FMODE_READ) {
5555 struct seq_file *m = file->private_data;
5559 parser = &fgd->parser;
5561 read = trace_get_user(parser, ubuf, cnt, ppos);
5563 if (read >= 0 && trace_parser_loaded(parser) &&
5564 !trace_parser_cont(parser)) {
5566 ret = ftrace_graph_set_hash(fgd->new_hash,
5568 trace_parser_clear(parser);
5577 static const struct file_operations ftrace_graph_fops = {
5578 .open = ftrace_graph_open,
5580 .write = ftrace_graph_write,
5581 .llseek = tracing_lseek,
5582 .release = ftrace_graph_release,
5585 static const struct file_operations ftrace_graph_notrace_fops = {
5586 .open = ftrace_graph_notrace_open,
5588 .write = ftrace_graph_write,
5589 .llseek = tracing_lseek,
5590 .release = ftrace_graph_release,
5592 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5594 void ftrace_create_filter_files(struct ftrace_ops *ops,
5595 struct dentry *parent)
5598 trace_create_file("set_ftrace_filter", 0644, parent,
5599 ops, &ftrace_filter_fops);
5601 trace_create_file("set_ftrace_notrace", 0644, parent,
5602 ops, &ftrace_notrace_fops);
5606 * The name "destroy_filter_files" is really a misnomer. Although
5607 * in the future, it may actualy delete the files, but this is
5608 * really intended to make sure the ops passed in are disabled
5609 * and that when this function returns, the caller is free to
5612 * The "destroy" name is only to match the "create" name that this
5613 * should be paired with.
5615 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
5617 mutex_lock(&ftrace_lock);
5618 if (ops->flags & FTRACE_OPS_FL_ENABLED)
5619 ftrace_shutdown(ops, 0);
5620 ops->flags |= FTRACE_OPS_FL_DELETED;
5621 ftrace_free_filter(ops);
5622 mutex_unlock(&ftrace_lock);
5625 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
5628 trace_create_file("available_filter_functions", 0444,
5629 d_tracer, NULL, &ftrace_avail_fops);
5631 trace_create_file("enabled_functions", 0444,
5632 d_tracer, NULL, &ftrace_enabled_fops);
5634 ftrace_create_filter_files(&global_ops, d_tracer);
5636 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5637 trace_create_file("set_graph_function", 0444, d_tracer,
5639 &ftrace_graph_fops);
5640 trace_create_file("set_graph_notrace", 0444, d_tracer,
5642 &ftrace_graph_notrace_fops);
5643 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5648 static int ftrace_cmp_ips(const void *a, const void *b)
5650 const unsigned long *ipa = a;
5651 const unsigned long *ipb = b;
5660 static int ftrace_process_locs(struct module *mod,
5661 unsigned long *start,
5664 struct ftrace_page *start_pg;
5665 struct ftrace_page *pg;
5666 struct dyn_ftrace *rec;
5667 unsigned long count;
5670 unsigned long flags = 0; /* Shut up gcc */
5673 count = end - start;
5678 sort(start, count, sizeof(*start),
5679 ftrace_cmp_ips, NULL);
5681 start_pg = ftrace_allocate_pages(count);
5685 mutex_lock(&ftrace_lock);
5688 * Core and each module needs their own pages, as
5689 * modules will free them when they are removed.
5690 * Force a new page to be allocated for modules.
5693 WARN_ON(ftrace_pages || ftrace_pages_start);
5694 /* First initialization */
5695 ftrace_pages = ftrace_pages_start = start_pg;
5700 if (WARN_ON(ftrace_pages->next)) {
5701 /* Hmm, we have free pages? */
5702 while (ftrace_pages->next)
5703 ftrace_pages = ftrace_pages->next;
5706 ftrace_pages->next = start_pg;
5712 addr = ftrace_call_adjust(*p++);
5714 * Some architecture linkers will pad between
5715 * the different mcount_loc sections of different
5716 * object files to satisfy alignments.
5717 * Skip any NULL pointers.
5722 if (pg->index == pg->size) {
5723 /* We should have allocated enough */
5724 if (WARN_ON(!pg->next))
5729 rec = &pg->records[pg->index++];
5733 /* We should have used all pages */
5736 /* Assign the last page to ftrace_pages */
5740 * We only need to disable interrupts on start up
5741 * because we are modifying code that an interrupt
5742 * may execute, and the modification is not atomic.
5743 * But for modules, nothing runs the code we modify
5744 * until we are finished with it, and there's no
5745 * reason to cause large interrupt latencies while we do it.
5748 local_irq_save(flags);
5749 ftrace_update_code(mod, start_pg);
5751 local_irq_restore(flags);
5754 mutex_unlock(&ftrace_lock);
5759 #ifdef CONFIG_MODULES
5761 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
5763 static int referenced_filters(struct dyn_ftrace *rec)
5765 struct ftrace_ops *ops;
5768 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
5769 if (ops_references_rec(ops, rec)) {
5771 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
5772 rec->flags |= FTRACE_FL_REGS;
5780 clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
5782 struct ftrace_func_entry *entry;
5783 struct dyn_ftrace *rec;
5786 if (ftrace_hash_empty(hash))
5789 for (i = 0; i < pg->index; i++) {
5790 rec = &pg->records[i];
5791 entry = __ftrace_lookup_ip(hash, rec->ip);
5793 * Do not allow this rec to match again.
5794 * Yeah, it may waste some memory, but will be removed
5795 * if/when the hash is modified again.
5802 /* Clear any records from hashs */
5803 static void clear_mod_from_hashes(struct ftrace_page *pg)
5805 struct trace_array *tr;
5807 mutex_lock(&trace_types_lock);
5808 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
5809 if (!tr->ops || !tr->ops->func_hash)
5811 mutex_lock(&tr->ops->func_hash->regex_lock);
5812 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
5813 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
5814 mutex_unlock(&tr->ops->func_hash->regex_lock);
5816 mutex_unlock(&trace_types_lock);
5819 void ftrace_release_mod(struct module *mod)
5821 struct dyn_ftrace *rec;
5822 struct ftrace_page **last_pg;
5823 struct ftrace_page *tmp_page = NULL;
5824 struct ftrace_page *pg;
5827 mutex_lock(&ftrace_lock);
5829 if (ftrace_disabled)
5833 * Each module has its own ftrace_pages, remove
5834 * them from the list.
5836 last_pg = &ftrace_pages_start;
5837 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
5838 rec = &pg->records[0];
5839 if (within_module_core(rec->ip, mod)) {
5841 * As core pages are first, the first
5842 * page should never be a module page.
5844 if (WARN_ON(pg == ftrace_pages_start))
5847 /* Check if we are deleting the last page */
5848 if (pg == ftrace_pages)
5849 ftrace_pages = next_to_ftrace_page(last_pg);
5851 ftrace_update_tot_cnt -= pg->index;
5852 *last_pg = pg->next;
5854 pg->next = tmp_page;
5857 last_pg = &pg->next;
5860 mutex_unlock(&ftrace_lock);
5862 for (pg = tmp_page; pg; pg = tmp_page) {
5864 /* Needs to be called outside of ftrace_lock */
5865 clear_mod_from_hashes(pg);
5867 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
5868 free_pages((unsigned long)pg->records, order);
5869 tmp_page = pg->next;
5874 void ftrace_module_enable(struct module *mod)
5876 struct dyn_ftrace *rec;
5877 struct ftrace_page *pg;
5879 mutex_lock(&ftrace_lock);
5881 if (ftrace_disabled)
5885 * If the tracing is enabled, go ahead and enable the record.
5887 * The reason not to enable the record immediatelly is the
5888 * inherent check of ftrace_make_nop/ftrace_make_call for
5889 * correct previous instructions. Making first the NOP
5890 * conversion puts the module to the correct state, thus
5891 * passing the ftrace_make_call check.
5893 * We also delay this to after the module code already set the
5894 * text to read-only, as we now need to set it back to read-write
5895 * so that we can modify the text.
5897 if (ftrace_start_up)
5898 ftrace_arch_code_modify_prepare();
5900 do_for_each_ftrace_rec(pg, rec) {
5903 * do_for_each_ftrace_rec() is a double loop.
5904 * module text shares the pg. If a record is
5905 * not part of this module, then skip this pg,
5906 * which the "break" will do.
5908 if (!within_module_core(rec->ip, mod))
5914 * When adding a module, we need to check if tracers are
5915 * currently enabled and if they are, and can trace this record,
5916 * we need to enable the module functions as well as update the
5917 * reference counts for those function records.
5919 if (ftrace_start_up)
5920 cnt += referenced_filters(rec);
5922 rec->flags &= ~FTRACE_FL_DISABLED;
5925 if (ftrace_start_up && cnt) {
5926 int failed = __ftrace_replace_code(rec, 1);
5928 ftrace_bug(failed, rec);
5933 } while_for_each_ftrace_rec();
5936 if (ftrace_start_up)
5937 ftrace_arch_code_modify_post_process();
5940 mutex_unlock(&ftrace_lock);
5942 process_cached_mods(mod->name);
5945 void ftrace_module_init(struct module *mod)
5947 if (ftrace_disabled || !mod->num_ftrace_callsites)
5950 ftrace_process_locs(mod, mod->ftrace_callsites,
5951 mod->ftrace_callsites + mod->num_ftrace_callsites);
5953 #endif /* CONFIG_MODULES */
5955 void __init ftrace_free_init_mem(void)
5957 unsigned long start = (unsigned long)(&__init_begin);
5958 unsigned long end = (unsigned long)(&__init_end);
5959 struct ftrace_page **last_pg = &ftrace_pages_start;
5960 struct ftrace_page *pg;
5961 struct dyn_ftrace *rec;
5962 struct dyn_ftrace key;
5966 key.flags = end; /* overload flags, as it is unsigned long */
5968 mutex_lock(&ftrace_lock);
5970 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
5971 if (end < pg->records[0].ip ||
5972 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
5975 rec = bsearch(&key, pg->records, pg->index,
5976 sizeof(struct dyn_ftrace),
5981 ftrace_update_tot_cnt--;
5983 *last_pg = pg->next;
5984 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
5985 free_pages((unsigned long)pg->records, order);
5987 pg = container_of(last_pg, struct ftrace_page, next);
5992 memmove(rec, rec + 1,
5993 (pg->index - (rec - pg->records)) * sizeof(*rec));
5994 /* More than one function may be in this block */
5997 mutex_unlock(&ftrace_lock);
6000 void __init ftrace_init(void)
6002 extern unsigned long __start_mcount_loc[];
6003 extern unsigned long __stop_mcount_loc[];
6004 unsigned long count, flags;
6007 local_irq_save(flags);
6008 ret = ftrace_dyn_arch_init();
6009 local_irq_restore(flags);
6013 count = __stop_mcount_loc - __start_mcount_loc;
6015 pr_info("ftrace: No functions to be traced?\n");
6019 pr_info("ftrace: allocating %ld entries in %ld pages\n",
6020 count, DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
6022 last_ftrace_enabled = ftrace_enabled = 1;
6024 ret = ftrace_process_locs(NULL,
6028 set_ftrace_early_filters();
6032 ftrace_disabled = 1;
6035 /* Do nothing if arch does not support this */
6036 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
6040 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6042 arch_ftrace_update_trampoline(ops);
6045 void ftrace_init_trace_array(struct trace_array *tr)
6047 INIT_LIST_HEAD(&tr->func_probes);
6048 INIT_LIST_HEAD(&tr->mod_trace);
6049 INIT_LIST_HEAD(&tr->mod_notrace);
6053 static struct ftrace_ops global_ops = {
6054 .func = ftrace_stub,
6055 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
6056 FTRACE_OPS_FL_INITIALIZED |
6060 static int __init ftrace_nodyn_init(void)
6065 core_initcall(ftrace_nodyn_init);
6067 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
6068 static inline void ftrace_startup_enable(int command) { }
6069 static inline void ftrace_startup_all(int command) { }
6070 /* Keep as macros so we do not need to define the commands */
6071 # define ftrace_startup(ops, command) \
6073 int ___ret = __register_ftrace_function(ops); \
6075 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
6078 # define ftrace_shutdown(ops, command) \
6080 int ___ret = __unregister_ftrace_function(ops); \
6082 (ops)->flags &= ~FTRACE_OPS_FL_ENABLED; \
6086 # define ftrace_startup_sysctl() do { } while (0)
6087 # define ftrace_shutdown_sysctl() do { } while (0)
6090 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
6095 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6099 #endif /* CONFIG_DYNAMIC_FTRACE */
6101 __init void ftrace_init_global_array_ops(struct trace_array *tr)
6103 tr->ops = &global_ops;
6104 tr->ops->private = tr;
6105 ftrace_init_trace_array(tr);
6108 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
6110 /* If we filter on pids, update to use the pid function */
6111 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
6112 if (WARN_ON(tr->ops->func != ftrace_stub))
6113 printk("ftrace ops had %pS for function\n",
6116 tr->ops->func = func;
6117 tr->ops->private = tr;
6120 void ftrace_reset_array_ops(struct trace_array *tr)
6122 tr->ops->func = ftrace_stub;
6125 static nokprobe_inline void
6126 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6127 struct ftrace_ops *ignored, struct pt_regs *regs)
6129 struct ftrace_ops *op;
6132 bit = trace_test_and_set_recursion(TRACE_LIST_START);
6137 * Some of the ops may be dynamically allocated,
6138 * they must be freed after a synchronize_sched().
6140 preempt_disable_notrace();
6142 do_for_each_ftrace_op(op, ftrace_ops_list) {
6144 * Check the following for each ops before calling their func:
6145 * if RCU flag is set, then rcu_is_watching() must be true
6146 * if PER_CPU is set, then ftrace_function_local_disable()
6148 * Otherwise test if the ip matches the ops filter
6150 * If any of the above fails then the op->func() is not executed.
6152 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
6153 (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
6154 !ftrace_function_local_disabled(op)) &&
6155 ftrace_ops_test(op, ip, regs)) {
6157 if (FTRACE_WARN_ON(!op->func)) {
6158 pr_warn("op=%p %pS\n", op, op);
6161 op->func(ip, parent_ip, op, regs);
6163 } while_for_each_ftrace_op(op);
6165 preempt_enable_notrace();
6166 trace_clear_recursion(bit);
6170 * Some archs only support passing ip and parent_ip. Even though
6171 * the list function ignores the op parameter, we do not want any
6172 * C side effects, where a function is called without the caller
6173 * sending a third parameter.
6174 * Archs are to support both the regs and ftrace_ops at the same time.
6175 * If they support ftrace_ops, it is assumed they support regs.
6176 * If call backs want to use regs, they must either check for regs
6177 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
6178 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
6179 * An architecture can pass partial regs with ftrace_ops and still
6180 * set the ARCH_SUPPORTS_FTRACE_OPS.
6182 #if ARCH_SUPPORTS_FTRACE_OPS
6183 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6184 struct ftrace_ops *op, struct pt_regs *regs)
6186 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
6188 NOKPROBE_SYMBOL(ftrace_ops_list_func);
6190 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
6192 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
6194 NOKPROBE_SYMBOL(ftrace_ops_no_ops);
6198 * If there's only one function registered but it does not support
6199 * recursion, needs RCU protection and/or requires per cpu handling, then
6200 * this function will be called by the mcount trampoline.
6202 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
6203 struct ftrace_ops *op, struct pt_regs *regs)
6207 bit = trace_test_and_set_recursion(TRACE_LIST_START);
6211 preempt_disable_notrace();
6213 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
6214 (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
6215 !ftrace_function_local_disabled(op))) {
6216 op->func(ip, parent_ip, op, regs);
6219 preempt_enable_notrace();
6220 trace_clear_recursion(bit);
6222 NOKPROBE_SYMBOL(ftrace_ops_assist_func);
6225 * ftrace_ops_get_func - get the function a trampoline should call
6226 * @ops: the ops to get the function for
6228 * Normally the mcount trampoline will call the ops->func, but there
6229 * are times that it should not. For example, if the ops does not
6230 * have its own recursion protection, then it should call the
6231 * ftrace_ops_assist_func() instead.
6233 * Returns the function that the trampoline should call for @ops.
6235 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
6238 * If the function does not handle recursion, needs to be RCU safe,
6239 * or does per cpu logic, then we need to call the assist handler.
6241 if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
6242 ops->flags & (FTRACE_OPS_FL_RCU | FTRACE_OPS_FL_PER_CPU))
6243 return ftrace_ops_assist_func;
6249 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
6250 struct task_struct *prev, struct task_struct *next)
6252 struct trace_array *tr = data;
6253 struct trace_pid_list *pid_list;
6255 pid_list = rcu_dereference_sched(tr->function_pids);
6257 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
6258 trace_ignore_this_task(pid_list, next));
6262 ftrace_pid_follow_sched_process_fork(void *data,
6263 struct task_struct *self,
6264 struct task_struct *task)
6266 struct trace_pid_list *pid_list;
6267 struct trace_array *tr = data;
6269 pid_list = rcu_dereference_sched(tr->function_pids);
6270 trace_filter_add_remove_task(pid_list, self, task);
6274 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
6276 struct trace_pid_list *pid_list;
6277 struct trace_array *tr = data;
6279 pid_list = rcu_dereference_sched(tr->function_pids);
6280 trace_filter_add_remove_task(pid_list, NULL, task);
6283 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
6286 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6288 register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
6291 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6293 unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
6298 static void clear_ftrace_pids(struct trace_array *tr)
6300 struct trace_pid_list *pid_list;
6303 pid_list = rcu_dereference_protected(tr->function_pids,
6304 lockdep_is_held(&ftrace_lock));
6308 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
6310 for_each_possible_cpu(cpu)
6311 per_cpu_ptr(tr->trace_buffer.data, cpu)->ftrace_ignore_pid = false;
6313 rcu_assign_pointer(tr->function_pids, NULL);
6315 /* Wait till all users are no longer using pid filtering */
6316 synchronize_sched();
6318 trace_free_pid_list(pid_list);
6321 void ftrace_clear_pids(struct trace_array *tr)
6323 mutex_lock(&ftrace_lock);
6325 clear_ftrace_pids(tr);
6327 mutex_unlock(&ftrace_lock);
6330 static void ftrace_pid_reset(struct trace_array *tr)
6332 mutex_lock(&ftrace_lock);
6333 clear_ftrace_pids(tr);
6335 ftrace_update_pid_func();
6336 ftrace_startup_all(0);
6338 mutex_unlock(&ftrace_lock);
6341 /* Greater than any max PID */
6342 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
6344 static void *fpid_start(struct seq_file *m, loff_t *pos)
6347 struct trace_pid_list *pid_list;
6348 struct trace_array *tr = m->private;
6350 mutex_lock(&ftrace_lock);
6351 rcu_read_lock_sched();
6353 pid_list = rcu_dereference_sched(tr->function_pids);
6356 return !(*pos) ? FTRACE_NO_PIDS : NULL;
6358 return trace_pid_start(pid_list, pos);
6361 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
6363 struct trace_array *tr = m->private;
6364 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
6366 if (v == FTRACE_NO_PIDS) {
6370 return trace_pid_next(pid_list, v, pos);
6373 static void fpid_stop(struct seq_file *m, void *p)
6376 rcu_read_unlock_sched();
6377 mutex_unlock(&ftrace_lock);
6380 static int fpid_show(struct seq_file *m, void *v)
6382 if (v == FTRACE_NO_PIDS) {
6383 seq_puts(m, "no pid\n");
6387 return trace_pid_show(m, v);
6390 static const struct seq_operations ftrace_pid_sops = {
6391 .start = fpid_start,
6398 ftrace_pid_open(struct inode *inode, struct file *file)
6400 struct trace_array *tr = inode->i_private;
6404 if (trace_array_get(tr) < 0)
6407 if ((file->f_mode & FMODE_WRITE) &&
6408 (file->f_flags & O_TRUNC))
6409 ftrace_pid_reset(tr);
6411 ret = seq_open(file, &ftrace_pid_sops);
6413 trace_array_put(tr);
6415 m = file->private_data;
6416 /* copy tr over to seq ops */
6423 static void ignore_task_cpu(void *data)
6425 struct trace_array *tr = data;
6426 struct trace_pid_list *pid_list;
6429 * This function is called by on_each_cpu() while the
6430 * event_mutex is held.
6432 pid_list = rcu_dereference_protected(tr->function_pids,
6433 mutex_is_locked(&ftrace_lock));
6435 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
6436 trace_ignore_this_task(pid_list, current));
6440 ftrace_pid_write(struct file *filp, const char __user *ubuf,
6441 size_t cnt, loff_t *ppos)
6443 struct seq_file *m = filp->private_data;
6444 struct trace_array *tr = m->private;
6445 struct trace_pid_list *filtered_pids = NULL;
6446 struct trace_pid_list *pid_list;
6452 mutex_lock(&ftrace_lock);
6454 filtered_pids = rcu_dereference_protected(tr->function_pids,
6455 lockdep_is_held(&ftrace_lock));
6457 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
6461 rcu_assign_pointer(tr->function_pids, pid_list);
6463 if (filtered_pids) {
6464 synchronize_sched();
6465 trace_free_pid_list(filtered_pids);
6466 } else if (pid_list) {
6467 /* Register a probe to set whether to ignore the tracing of a task */
6468 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
6472 * Ignoring of pids is done at task switch. But we have to
6473 * check for those tasks that are currently running.
6474 * Always do this in case a pid was appended or removed.
6476 on_each_cpu(ignore_task_cpu, tr, 1);
6478 ftrace_update_pid_func();
6479 ftrace_startup_all(0);
6481 mutex_unlock(&ftrace_lock);
6490 ftrace_pid_release(struct inode *inode, struct file *file)
6492 struct trace_array *tr = inode->i_private;
6494 trace_array_put(tr);
6496 return seq_release(inode, file);
6499 static const struct file_operations ftrace_pid_fops = {
6500 .open = ftrace_pid_open,
6501 .write = ftrace_pid_write,
6503 .llseek = tracing_lseek,
6504 .release = ftrace_pid_release,
6507 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
6509 trace_create_file("set_ftrace_pid", 0644, d_tracer,
6510 tr, &ftrace_pid_fops);
6513 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
6514 struct dentry *d_tracer)
6516 /* Only the top level directory has the dyn_tracefs and profile */
6517 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
6519 ftrace_init_dyn_tracefs(d_tracer);
6520 ftrace_profile_tracefs(d_tracer);
6524 * ftrace_kill - kill ftrace
6526 * This function should be used by panic code. It stops ftrace
6527 * but in a not so nice way. If you need to simply kill ftrace
6528 * from a non-atomic section, use ftrace_kill.
6530 void ftrace_kill(void)
6532 ftrace_disabled = 1;
6534 clear_ftrace_function();
6538 * Test if ftrace is dead or not.
6540 int ftrace_is_dead(void)
6542 return ftrace_disabled;
6546 * register_ftrace_function - register a function for profiling
6547 * @ops - ops structure that holds the function for profiling.
6549 * Register a function to be called by all functions in the
6552 * Note: @ops->func and all the functions it calls must be labeled
6553 * with "notrace", otherwise it will go into a
6556 int register_ftrace_function(struct ftrace_ops *ops)
6560 ftrace_ops_init(ops);
6562 mutex_lock(&ftrace_lock);
6564 ret = ftrace_startup(ops, 0);
6566 mutex_unlock(&ftrace_lock);
6570 EXPORT_SYMBOL_GPL(register_ftrace_function);
6573 * unregister_ftrace_function - unregister a function for profiling.
6574 * @ops - ops structure that holds the function to unregister
6576 * Unregister a function that was added to be called by ftrace profiling.
6578 int unregister_ftrace_function(struct ftrace_ops *ops)
6582 mutex_lock(&ftrace_lock);
6583 ret = ftrace_shutdown(ops, 0);
6584 mutex_unlock(&ftrace_lock);
6588 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
6591 ftrace_enable_sysctl(struct ctl_table *table, int write,
6592 void __user *buffer, size_t *lenp,
6597 mutex_lock(&ftrace_lock);
6599 if (unlikely(ftrace_disabled))
6602 ret = proc_dointvec(table, write, buffer, lenp, ppos);
6604 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
6607 last_ftrace_enabled = !!ftrace_enabled;
6609 if (ftrace_enabled) {
6611 /* we are starting ftrace again */
6612 if (rcu_dereference_protected(ftrace_ops_list,
6613 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
6614 update_ftrace_function();
6616 ftrace_startup_sysctl();
6619 /* stopping ftrace calls (just send to ftrace_stub) */
6620 ftrace_trace_function = ftrace_stub;
6622 ftrace_shutdown_sysctl();
6626 mutex_unlock(&ftrace_lock);
6630 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
6632 static struct ftrace_ops graph_ops = {
6633 .func = ftrace_stub,
6634 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
6635 FTRACE_OPS_FL_INITIALIZED |
6638 #ifdef FTRACE_GRAPH_TRAMP_ADDR
6639 .trampoline = FTRACE_GRAPH_TRAMP_ADDR,
6640 /* trampoline_size is only needed for dynamically allocated tramps */
6642 ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash)
6645 void ftrace_graph_sleep_time_control(bool enable)
6647 fgraph_sleep_time = enable;
6650 void ftrace_graph_graph_time_control(bool enable)
6652 fgraph_graph_time = enable;
6655 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
6660 /* The callbacks that hook a function */
6661 trace_func_graph_ret_t ftrace_graph_return =
6662 (trace_func_graph_ret_t)ftrace_stub;
6663 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
6664 static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
6666 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
6667 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
6671 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
6672 struct task_struct *g, *t;
6674 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
6675 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
6676 * sizeof(struct ftrace_ret_stack),
6678 if (!ret_stack_list[i]) {
6686 read_lock(&tasklist_lock);
6687 do_each_thread(g, t) {
6693 if (t->ret_stack == NULL) {
6694 atomic_set(&t->trace_overrun, 0);
6695 t->curr_ret_stack = -1;
6696 /* Make sure the tasks see the -1 first: */
6698 t->ret_stack = ret_stack_list[start++];
6700 } while_each_thread(g, t);
6703 read_unlock(&tasklist_lock);
6705 for (i = start; i < end; i++)
6706 kfree(ret_stack_list[i]);
6711 ftrace_graph_probe_sched_switch(void *ignore, bool preempt,
6712 struct task_struct *prev, struct task_struct *next)
6714 unsigned long long timestamp;
6718 * Does the user want to count the time a function was asleep.
6719 * If so, do not update the time stamps.
6721 if (fgraph_sleep_time)
6724 timestamp = trace_clock_local();
6726 prev->ftrace_timestamp = timestamp;
6728 /* only process tasks that we timestamped */
6729 if (!next->ftrace_timestamp)
6733 * Update all the counters in next to make up for the
6734 * time next was sleeping.
6736 timestamp -= next->ftrace_timestamp;
6738 for (index = next->curr_ret_stack; index >= 0; index--)
6739 next->ret_stack[index].calltime += timestamp;
6742 /* Allocate a return stack for each task */
6743 static int start_graph_tracing(void)
6745 struct ftrace_ret_stack **ret_stack_list;
6748 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
6749 sizeof(struct ftrace_ret_stack *),
6752 if (!ret_stack_list)
6755 /* The cpu_boot init_task->ret_stack will never be freed */
6756 for_each_online_cpu(cpu) {
6757 if (!idle_task(cpu)->ret_stack)
6758 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
6762 ret = alloc_retstack_tasklist(ret_stack_list);
6763 } while (ret == -EAGAIN);
6766 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
6768 pr_info("ftrace_graph: Couldn't activate tracepoint"
6769 " probe to kernel_sched_switch\n");
6772 kfree(ret_stack_list);
6777 * Hibernation protection.
6778 * The state of the current task is too much unstable during
6779 * suspend/restore to disk. We want to protect against that.
6782 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
6786 case PM_HIBERNATION_PREPARE:
6787 pause_graph_tracing();
6790 case PM_POST_HIBERNATION:
6791 unpause_graph_tracing();
6797 static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
6799 if (!ftrace_ops_test(&global_ops, trace->func, NULL))
6801 return __ftrace_graph_entry(trace);
6805 * The function graph tracer should only trace the functions defined
6806 * by set_ftrace_filter and set_ftrace_notrace. If another function
6807 * tracer ops is registered, the graph tracer requires testing the
6808 * function against the global ops, and not just trace any function
6809 * that any ftrace_ops registered.
6811 static void update_function_graph_func(void)
6813 struct ftrace_ops *op;
6814 bool do_test = false;
6817 * The graph and global ops share the same set of functions
6818 * to test. If any other ops is on the list, then
6819 * the graph tracing needs to test if its the function
6822 do_for_each_ftrace_op(op, ftrace_ops_list) {
6823 if (op != &global_ops && op != &graph_ops &&
6824 op != &ftrace_list_end) {
6826 /* in double loop, break out with goto */
6829 } while_for_each_ftrace_op(op);
6832 ftrace_graph_entry = ftrace_graph_entry_test;
6834 ftrace_graph_entry = __ftrace_graph_entry;
6837 static struct notifier_block ftrace_suspend_notifier = {
6838 .notifier_call = ftrace_suspend_notifier_call,
6841 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
6842 trace_func_graph_ent_t entryfunc)
6846 mutex_lock(&ftrace_lock);
6848 /* we currently allow only one tracer registered at a time */
6849 if (ftrace_graph_active) {
6854 register_pm_notifier(&ftrace_suspend_notifier);
6856 ftrace_graph_active++;
6857 ret = start_graph_tracing();
6859 ftrace_graph_active--;
6863 ftrace_graph_return = retfunc;
6866 * Update the indirect function to the entryfunc, and the
6867 * function that gets called to the entry_test first. Then
6868 * call the update fgraph entry function to determine if
6869 * the entryfunc should be called directly or not.
6871 __ftrace_graph_entry = entryfunc;
6872 ftrace_graph_entry = ftrace_graph_entry_test;
6873 update_function_graph_func();
6875 ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET);
6877 mutex_unlock(&ftrace_lock);
6881 void unregister_ftrace_graph(void)
6883 mutex_lock(&ftrace_lock);
6885 if (unlikely(!ftrace_graph_active))
6888 ftrace_graph_active--;
6889 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
6890 ftrace_graph_entry = ftrace_graph_entry_stub;
6891 __ftrace_graph_entry = ftrace_graph_entry_stub;
6892 ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET);
6893 unregister_pm_notifier(&ftrace_suspend_notifier);
6894 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
6897 mutex_unlock(&ftrace_lock);
6900 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
6903 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
6905 atomic_set(&t->trace_overrun, 0);
6906 t->ftrace_timestamp = 0;
6907 /* make curr_ret_stack visible before we add the ret_stack */
6909 t->ret_stack = ret_stack;
6913 * Allocate a return stack for the idle task. May be the first
6914 * time through, or it may be done by CPU hotplug online.
6916 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
6918 t->curr_ret_stack = -1;
6920 * The idle task has no parent, it either has its own
6921 * stack or no stack at all.
6924 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
6926 if (ftrace_graph_active) {
6927 struct ftrace_ret_stack *ret_stack;
6929 ret_stack = per_cpu(idle_ret_stack, cpu);
6931 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
6932 * sizeof(struct ftrace_ret_stack),
6936 per_cpu(idle_ret_stack, cpu) = ret_stack;
6938 graph_init_task(t, ret_stack);
6942 /* Allocate a return stack for newly created task */
6943 void ftrace_graph_init_task(struct task_struct *t)
6945 /* Make sure we do not use the parent ret_stack */
6946 t->ret_stack = NULL;
6947 t->curr_ret_stack = -1;
6949 if (ftrace_graph_active) {
6950 struct ftrace_ret_stack *ret_stack;
6952 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
6953 * sizeof(struct ftrace_ret_stack),
6957 graph_init_task(t, ret_stack);
6961 void ftrace_graph_exit_task(struct task_struct *t)
6963 struct ftrace_ret_stack *ret_stack = t->ret_stack;
6965 t->ret_stack = NULL;
6966 /* NULL must become visible to IRQs before we free it: */