1 // SPDX-License-Identifier: GPL-2.0
3 * Infrastructure for profiling code inserted by 'gcc -pg'.
5 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
6 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
8 * Originally ported from the -rt patch by:
9 * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
11 * Based on code in the latency_tracer, that is:
13 * Copyright (C) 2004-2006 Ingo Molnar
14 * Copyright (C) 2004 Nadia Yvette Chambers
17 #include <linux/stop_machine.h>
18 #include <linux/clocksource.h>
19 #include <linux/sched/task.h>
20 #include <linux/kallsyms.h>
21 #include <linux/security.h>
22 #include <linux/seq_file.h>
23 #include <linux/tracefs.h>
24 #include <linux/hardirq.h>
25 #include <linux/kthread.h>
26 #include <linux/uaccess.h>
27 #include <linux/bsearch.h>
28 #include <linux/module.h>
29 #include <linux/ftrace.h>
30 #include <linux/sysctl.h>
31 #include <linux/slab.h>
32 #include <linux/ctype.h>
33 #include <linux/sort.h>
34 #include <linux/list.h>
35 #include <linux/hash.h>
36 #include <linux/rcupdate.h>
37 #include <linux/kprobes.h>
39 #include <trace/events/sched.h>
41 #include <asm/sections.h>
42 #include <asm/setup.h>
44 #include "ftrace_internal.h"
45 #include "trace_output.h"
46 #include "trace_stat.h"
48 /* Flags that do not get reset */
49 #define FTRACE_NOCLEAR_FLAGS (FTRACE_FL_DISABLED | FTRACE_FL_TOUCHED | \
52 #define FTRACE_INVALID_FUNCTION "__ftrace_invalid_address__"
54 #define FTRACE_WARN_ON(cond) \
62 #define FTRACE_WARN_ON_ONCE(cond) \
65 if (WARN_ON_ONCE(___r)) \
70 /* hash bits for specific function selection */
71 #define FTRACE_HASH_DEFAULT_BITS 10
72 #define FTRACE_HASH_MAX_BITS 12
74 #ifdef CONFIG_DYNAMIC_FTRACE
75 #define INIT_OPS_HASH(opsname) \
76 .func_hash = &opsname.local_hash, \
77 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
79 #define INIT_OPS_HASH(opsname)
83 FTRACE_MODIFY_ENABLE_FL = (1 << 0),
84 FTRACE_MODIFY_MAY_SLEEP_FL = (1 << 1),
87 struct ftrace_ops ftrace_list_end __read_mostly = {
89 .flags = FTRACE_OPS_FL_STUB,
90 INIT_OPS_HASH(ftrace_list_end)
93 /* ftrace_enabled is a method to turn ftrace on or off */
94 int ftrace_enabled __read_mostly;
95 static int __maybe_unused last_ftrace_enabled;
97 /* Current function tracing op */
98 struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
99 /* What to set function_trace_op to */
100 static struct ftrace_ops *set_function_trace_op;
102 static bool ftrace_pids_enabled(struct ftrace_ops *ops)
104 struct trace_array *tr;
106 if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
111 return tr->function_pids != NULL || tr->function_no_pids != NULL;
114 static void ftrace_update_trampoline(struct ftrace_ops *ops);
117 * ftrace_disabled is set when an anomaly is discovered.
118 * ftrace_disabled is much stronger than ftrace_enabled.
120 static int ftrace_disabled __read_mostly;
122 DEFINE_MUTEX(ftrace_lock);
124 struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
125 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
126 struct ftrace_ops global_ops;
128 /* Defined by vmlinux.lds.h see the comment above arch_ftrace_ops_list_func for details */
129 void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
130 struct ftrace_ops *op, struct ftrace_regs *fregs);
132 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS
134 * Stub used to invoke the list ops without requiring a separate trampoline.
136 const struct ftrace_ops ftrace_list_ops = {
137 .func = ftrace_ops_list_func,
138 .flags = FTRACE_OPS_FL_STUB,
141 static void ftrace_ops_nop_func(unsigned long ip, unsigned long parent_ip,
142 struct ftrace_ops *op,
143 struct ftrace_regs *fregs)
149 * Stub used when a call site is disabled. May be called transiently by threads
150 * which have made it into ftrace_caller but haven't yet recovered the ops at
151 * the point the call site is disabled.
153 const struct ftrace_ops ftrace_nop_ops = {
154 .func = ftrace_ops_nop_func,
155 .flags = FTRACE_OPS_FL_STUB,
159 static inline void ftrace_ops_init(struct ftrace_ops *ops)
161 #ifdef CONFIG_DYNAMIC_FTRACE
162 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
163 mutex_init(&ops->local_hash.regex_lock);
164 ops->func_hash = &ops->local_hash;
165 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
170 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
171 struct ftrace_ops *op, struct ftrace_regs *fregs)
173 struct trace_array *tr = op->private;
177 pid = this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid);
178 if (pid == FTRACE_PID_IGNORE)
180 if (pid != FTRACE_PID_TRACE &&
185 op->saved_func(ip, parent_ip, op, fregs);
188 static void ftrace_sync_ipi(void *data)
190 /* Probably not needed, but do it anyway */
194 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
197 * If this is a dynamic or RCU ops, or we force list func,
198 * then it needs to call the list anyway.
200 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
201 FTRACE_FORCE_LIST_FUNC)
202 return ftrace_ops_list_func;
204 return ftrace_ops_get_func(ops);
207 static void update_ftrace_function(void)
212 * Prepare the ftrace_ops that the arch callback will use.
213 * If there's only one ftrace_ops registered, the ftrace_ops_list
214 * will point to the ops we want.
216 set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
217 lockdep_is_held(&ftrace_lock));
219 /* If there's no ftrace_ops registered, just call the stub function */
220 if (set_function_trace_op == &ftrace_list_end) {
224 * If we are at the end of the list and this ops is
225 * recursion safe and not dynamic and the arch supports passing ops,
226 * then have the mcount trampoline call the function directly.
228 } else if (rcu_dereference_protected(ftrace_ops_list->next,
229 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
230 func = ftrace_ops_get_list_func(ftrace_ops_list);
233 /* Just use the default ftrace_ops */
234 set_function_trace_op = &ftrace_list_end;
235 func = ftrace_ops_list_func;
238 update_function_graph_func();
240 /* If there's no change, then do nothing more here */
241 if (ftrace_trace_function == func)
245 * If we are using the list function, it doesn't care
246 * about the function_trace_ops.
248 if (func == ftrace_ops_list_func) {
249 ftrace_trace_function = func;
251 * Don't even bother setting function_trace_ops,
252 * it would be racy to do so anyway.
257 #ifndef CONFIG_DYNAMIC_FTRACE
259 * For static tracing, we need to be a bit more careful.
260 * The function change takes affect immediately. Thus,
261 * we need to coordinate the setting of the function_trace_ops
262 * with the setting of the ftrace_trace_function.
264 * Set the function to the list ops, which will call the
265 * function we want, albeit indirectly, but it handles the
266 * ftrace_ops and doesn't depend on function_trace_op.
268 ftrace_trace_function = ftrace_ops_list_func;
270 * Make sure all CPUs see this. Yes this is slow, but static
271 * tracing is slow and nasty to have enabled.
273 synchronize_rcu_tasks_rude();
274 /* Now all cpus are using the list ops. */
275 function_trace_op = set_function_trace_op;
276 /* Make sure the function_trace_op is visible on all CPUs */
278 /* Nasty way to force a rmb on all cpus */
279 smp_call_function(ftrace_sync_ipi, NULL, 1);
280 /* OK, we are all set to update the ftrace_trace_function now! */
281 #endif /* !CONFIG_DYNAMIC_FTRACE */
283 ftrace_trace_function = func;
286 static void add_ftrace_ops(struct ftrace_ops __rcu **list,
287 struct ftrace_ops *ops)
289 rcu_assign_pointer(ops->next, *list);
292 * We are entering ops into the list but another
293 * CPU might be walking that list. We need to make sure
294 * the ops->next pointer is valid before another CPU sees
295 * the ops pointer included into the list.
297 rcu_assign_pointer(*list, ops);
300 static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
301 struct ftrace_ops *ops)
303 struct ftrace_ops **p;
306 * If we are removing the last function, then simply point
307 * to the ftrace_stub.
309 if (rcu_dereference_protected(*list,
310 lockdep_is_held(&ftrace_lock)) == ops &&
311 rcu_dereference_protected(ops->next,
312 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
313 *list = &ftrace_list_end;
317 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
328 static void ftrace_update_trampoline(struct ftrace_ops *ops);
330 int __register_ftrace_function(struct ftrace_ops *ops)
332 if (ops->flags & FTRACE_OPS_FL_DELETED)
335 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
338 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
340 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
341 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
342 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
344 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
345 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
348 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
349 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
351 if (!ftrace_enabled && (ops->flags & FTRACE_OPS_FL_PERMANENT))
354 if (!is_kernel_core_data((unsigned long)ops))
355 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
357 add_ftrace_ops(&ftrace_ops_list, ops);
359 /* Always save the function, and reset at unregistering */
360 ops->saved_func = ops->func;
362 if (ftrace_pids_enabled(ops))
363 ops->func = ftrace_pid_func;
365 ftrace_update_trampoline(ops);
368 update_ftrace_function();
373 int __unregister_ftrace_function(struct ftrace_ops *ops)
377 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
380 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
386 update_ftrace_function();
388 ops->func = ops->saved_func;
393 static void ftrace_update_pid_func(void)
395 struct ftrace_ops *op;
397 /* Only do something if we are tracing something */
398 if (ftrace_trace_function == ftrace_stub)
401 do_for_each_ftrace_op(op, ftrace_ops_list) {
402 if (op->flags & FTRACE_OPS_FL_PID) {
403 op->func = ftrace_pids_enabled(op) ?
404 ftrace_pid_func : op->saved_func;
405 ftrace_update_trampoline(op);
407 } while_for_each_ftrace_op(op);
409 update_ftrace_function();
412 #ifdef CONFIG_FUNCTION_PROFILER
413 struct ftrace_profile {
414 struct hlist_node node;
416 unsigned long counter;
417 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
418 unsigned long long time;
419 unsigned long long time_squared;
423 struct ftrace_profile_page {
424 struct ftrace_profile_page *next;
426 struct ftrace_profile records[];
429 struct ftrace_profile_stat {
431 struct hlist_head *hash;
432 struct ftrace_profile_page *pages;
433 struct ftrace_profile_page *start;
434 struct tracer_stat stat;
437 #define PROFILE_RECORDS_SIZE \
438 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
440 #define PROFILES_PER_PAGE \
441 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
443 static int ftrace_profile_enabled __read_mostly;
445 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
446 static DEFINE_MUTEX(ftrace_profile_lock);
448 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
450 #define FTRACE_PROFILE_HASH_BITS 10
451 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
454 function_stat_next(void *v, int idx)
456 struct ftrace_profile *rec = v;
457 struct ftrace_profile_page *pg;
459 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
465 if ((void *)rec >= (void *)&pg->records[pg->index]) {
469 rec = &pg->records[0];
477 static void *function_stat_start(struct tracer_stat *trace)
479 struct ftrace_profile_stat *stat =
480 container_of(trace, struct ftrace_profile_stat, stat);
482 if (!stat || !stat->start)
485 return function_stat_next(&stat->start->records[0], 0);
488 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
489 /* function graph compares on total time */
490 static int function_stat_cmp(const void *p1, const void *p2)
492 const struct ftrace_profile *a = p1;
493 const struct ftrace_profile *b = p2;
495 if (a->time < b->time)
497 if (a->time > b->time)
503 /* not function graph compares against hits */
504 static int function_stat_cmp(const void *p1, const void *p2)
506 const struct ftrace_profile *a = p1;
507 const struct ftrace_profile *b = p2;
509 if (a->counter < b->counter)
511 if (a->counter > b->counter)
518 static int function_stat_headers(struct seq_file *m)
520 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
521 seq_puts(m, " Function "
524 "--- ---- --- ---\n");
526 seq_puts(m, " Function Hit\n"
532 static int function_stat_show(struct seq_file *m, void *v)
534 struct ftrace_profile *rec = v;
535 char str[KSYM_SYMBOL_LEN];
537 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
538 static struct trace_seq s;
539 unsigned long long avg;
540 unsigned long long stddev;
542 mutex_lock(&ftrace_profile_lock);
544 /* we raced with function_profile_reset() */
545 if (unlikely(rec->counter == 0)) {
550 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
551 avg = div64_ul(rec->time, rec->counter);
552 if (tracing_thresh && (avg < tracing_thresh))
556 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
557 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
559 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
562 /* Sample standard deviation (s^2) */
563 if (rec->counter <= 1)
567 * Apply Welford's method:
568 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
570 stddev = rec->counter * rec->time_squared -
571 rec->time * rec->time;
574 * Divide only 1000 for ns^2 -> us^2 conversion.
575 * trace_print_graph_duration will divide 1000 again.
577 stddev = div64_ul(stddev,
578 rec->counter * (rec->counter - 1) * 1000);
582 trace_print_graph_duration(rec->time, &s);
583 trace_seq_puts(&s, " ");
584 trace_print_graph_duration(avg, &s);
585 trace_seq_puts(&s, " ");
586 trace_print_graph_duration(stddev, &s);
587 trace_print_seq(m, &s);
591 mutex_unlock(&ftrace_profile_lock);
596 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
598 struct ftrace_profile_page *pg;
600 pg = stat->pages = stat->start;
603 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
608 memset(stat->hash, 0,
609 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
612 static int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
614 struct ftrace_profile_page *pg;
619 /* If we already allocated, do nothing */
623 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
627 #ifdef CONFIG_DYNAMIC_FTRACE
628 functions = ftrace_update_tot_cnt;
631 * We do not know the number of functions that exist because
632 * dynamic tracing is what counts them. With past experience
633 * we have around 20K functions. That should be more than enough.
634 * It is highly unlikely we will execute every function in
640 pg = stat->start = stat->pages;
642 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
644 for (i = 1; i < pages; i++) {
645 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
656 unsigned long tmp = (unsigned long)pg;
668 static int ftrace_profile_init_cpu(int cpu)
670 struct ftrace_profile_stat *stat;
673 stat = &per_cpu(ftrace_profile_stats, cpu);
676 /* If the profile is already created, simply reset it */
677 ftrace_profile_reset(stat);
682 * We are profiling all functions, but usually only a few thousand
683 * functions are hit. We'll make a hash of 1024 items.
685 size = FTRACE_PROFILE_HASH_SIZE;
687 stat->hash = kcalloc(size, sizeof(struct hlist_head), GFP_KERNEL);
692 /* Preallocate the function profiling pages */
693 if (ftrace_profile_pages_init(stat) < 0) {
702 static int ftrace_profile_init(void)
707 for_each_possible_cpu(cpu) {
708 ret = ftrace_profile_init_cpu(cpu);
716 /* interrupts must be disabled */
717 static struct ftrace_profile *
718 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
720 struct ftrace_profile *rec;
721 struct hlist_head *hhd;
724 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
725 hhd = &stat->hash[key];
727 if (hlist_empty(hhd))
730 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
738 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
739 struct ftrace_profile *rec)
743 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
744 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
748 * The memory is already allocated, this simply finds a new record to use.
750 static struct ftrace_profile *
751 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
753 struct ftrace_profile *rec = NULL;
755 /* prevent recursion (from NMIs) */
756 if (atomic_inc_return(&stat->disabled) != 1)
760 * Try to find the function again since an NMI
761 * could have added it
763 rec = ftrace_find_profiled_func(stat, ip);
767 if (stat->pages->index == PROFILES_PER_PAGE) {
768 if (!stat->pages->next)
770 stat->pages = stat->pages->next;
773 rec = &stat->pages->records[stat->pages->index++];
775 ftrace_add_profile(stat, rec);
778 atomic_dec(&stat->disabled);
784 function_profile_call(unsigned long ip, unsigned long parent_ip,
785 struct ftrace_ops *ops, struct ftrace_regs *fregs)
787 struct ftrace_profile_stat *stat;
788 struct ftrace_profile *rec;
791 if (!ftrace_profile_enabled)
794 local_irq_save(flags);
796 stat = this_cpu_ptr(&ftrace_profile_stats);
797 if (!stat->hash || !ftrace_profile_enabled)
800 rec = ftrace_find_profiled_func(stat, ip);
802 rec = ftrace_profile_alloc(stat, ip);
809 local_irq_restore(flags);
812 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
813 static bool fgraph_graph_time = true;
815 void ftrace_graph_graph_time_control(bool enable)
817 fgraph_graph_time = enable;
820 static int profile_graph_entry(struct ftrace_graph_ent *trace)
822 struct ftrace_ret_stack *ret_stack;
824 function_profile_call(trace->func, 0, NULL, NULL);
826 /* If function graph is shutting down, ret_stack can be NULL */
827 if (!current->ret_stack)
830 ret_stack = ftrace_graph_get_ret_stack(current, 0);
832 ret_stack->subtime = 0;
837 static void profile_graph_return(struct ftrace_graph_ret *trace)
839 struct ftrace_ret_stack *ret_stack;
840 struct ftrace_profile_stat *stat;
841 unsigned long long calltime;
842 struct ftrace_profile *rec;
845 local_irq_save(flags);
846 stat = this_cpu_ptr(&ftrace_profile_stats);
847 if (!stat->hash || !ftrace_profile_enabled)
850 /* If the calltime was zero'd ignore it */
851 if (!trace->calltime)
854 calltime = trace->rettime - trace->calltime;
856 if (!fgraph_graph_time) {
858 /* Append this call time to the parent time to subtract */
859 ret_stack = ftrace_graph_get_ret_stack(current, 1);
861 ret_stack->subtime += calltime;
863 ret_stack = ftrace_graph_get_ret_stack(current, 0);
864 if (ret_stack && ret_stack->subtime < calltime)
865 calltime -= ret_stack->subtime;
870 rec = ftrace_find_profiled_func(stat, trace->func);
872 rec->time += calltime;
873 rec->time_squared += calltime * calltime;
877 local_irq_restore(flags);
880 static struct fgraph_ops fprofiler_ops = {
881 .entryfunc = &profile_graph_entry,
882 .retfunc = &profile_graph_return,
885 static int register_ftrace_profiler(void)
887 return register_ftrace_graph(&fprofiler_ops);
890 static void unregister_ftrace_profiler(void)
892 unregister_ftrace_graph(&fprofiler_ops);
895 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
896 .func = function_profile_call,
897 .flags = FTRACE_OPS_FL_INITIALIZED,
898 INIT_OPS_HASH(ftrace_profile_ops)
901 static int register_ftrace_profiler(void)
903 return register_ftrace_function(&ftrace_profile_ops);
906 static void unregister_ftrace_profiler(void)
908 unregister_ftrace_function(&ftrace_profile_ops);
910 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
913 ftrace_profile_write(struct file *filp, const char __user *ubuf,
914 size_t cnt, loff_t *ppos)
919 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
925 mutex_lock(&ftrace_profile_lock);
926 if (ftrace_profile_enabled ^ val) {
928 ret = ftrace_profile_init();
934 ret = register_ftrace_profiler();
939 ftrace_profile_enabled = 1;
941 ftrace_profile_enabled = 0;
943 * unregister_ftrace_profiler calls stop_machine
944 * so this acts like an synchronize_rcu.
946 unregister_ftrace_profiler();
950 mutex_unlock(&ftrace_profile_lock);
958 ftrace_profile_read(struct file *filp, char __user *ubuf,
959 size_t cnt, loff_t *ppos)
961 char buf[64]; /* big enough to hold a number */
964 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
965 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
968 static const struct file_operations ftrace_profile_fops = {
969 .open = tracing_open_generic,
970 .read = ftrace_profile_read,
971 .write = ftrace_profile_write,
972 .llseek = default_llseek,
975 /* used to initialize the real stat files */
976 static struct tracer_stat function_stats __initdata = {
978 .stat_start = function_stat_start,
979 .stat_next = function_stat_next,
980 .stat_cmp = function_stat_cmp,
981 .stat_headers = function_stat_headers,
982 .stat_show = function_stat_show
985 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
987 struct ftrace_profile_stat *stat;
992 for_each_possible_cpu(cpu) {
993 stat = &per_cpu(ftrace_profile_stats, cpu);
995 name = kasprintf(GFP_KERNEL, "function%d", cpu);
998 * The files created are permanent, if something happens
999 * we still do not free memory.
1002 "Could not allocate stat file for cpu %d\n",
1006 stat->stat = function_stats;
1007 stat->stat.name = name;
1008 ret = register_stat_tracer(&stat->stat);
1011 "Could not register function stat for cpu %d\n",
1018 trace_create_file("function_profile_enabled",
1019 TRACE_MODE_WRITE, d_tracer, NULL,
1020 &ftrace_profile_fops);
1023 #else /* CONFIG_FUNCTION_PROFILER */
1024 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1027 #endif /* CONFIG_FUNCTION_PROFILER */
1029 #ifdef CONFIG_DYNAMIC_FTRACE
1031 static struct ftrace_ops *removed_ops;
1034 * Set when doing a global update, like enabling all recs or disabling them.
1035 * It is not set when just updating a single ftrace_ops.
1037 static bool update_all_ops;
1039 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1040 # error Dynamic ftrace depends on MCOUNT_RECORD
1043 struct ftrace_func_probe {
1044 struct ftrace_probe_ops *probe_ops;
1045 struct ftrace_ops ops;
1046 struct trace_array *tr;
1047 struct list_head list;
1053 * We make these constant because no one should touch them,
1054 * but they are used as the default "empty hash", to avoid allocating
1055 * it all the time. These are in a read only section such that if
1056 * anyone does try to modify it, it will cause an exception.
1058 static const struct hlist_head empty_buckets[1];
1059 static const struct ftrace_hash empty_hash = {
1060 .buckets = (struct hlist_head *)empty_buckets,
1062 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1064 struct ftrace_ops global_ops = {
1065 .func = ftrace_stub,
1066 .local_hash.notrace_hash = EMPTY_HASH,
1067 .local_hash.filter_hash = EMPTY_HASH,
1068 INIT_OPS_HASH(global_ops)
1069 .flags = FTRACE_OPS_FL_INITIALIZED |
1074 * Used by the stack unwinder to know about dynamic ftrace trampolines.
1076 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
1078 struct ftrace_ops *op = NULL;
1081 * Some of the ops may be dynamically allocated,
1082 * they are freed after a synchronize_rcu().
1084 preempt_disable_notrace();
1086 do_for_each_ftrace_op(op, ftrace_ops_list) {
1088 * This is to check for dynamically allocated trampolines.
1089 * Trampolines that are in kernel text will have
1090 * core_kernel_text() return true.
1092 if (op->trampoline && op->trampoline_size)
1093 if (addr >= op->trampoline &&
1094 addr < op->trampoline + op->trampoline_size) {
1095 preempt_enable_notrace();
1098 } while_for_each_ftrace_op(op);
1099 preempt_enable_notrace();
1105 * This is used by __kernel_text_address() to return true if the
1106 * address is on a dynamically allocated trampoline that would
1107 * not return true for either core_kernel_text() or
1108 * is_module_text_address().
1110 bool is_ftrace_trampoline(unsigned long addr)
1112 return ftrace_ops_trampoline(addr) != NULL;
1115 struct ftrace_page {
1116 struct ftrace_page *next;
1117 struct dyn_ftrace *records;
1122 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1123 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1125 static struct ftrace_page *ftrace_pages_start;
1126 static struct ftrace_page *ftrace_pages;
1128 static __always_inline unsigned long
1129 ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1131 if (hash->size_bits > 0)
1132 return hash_long(ip, hash->size_bits);
1137 /* Only use this function if ftrace_hash_empty() has already been tested */
1138 static __always_inline struct ftrace_func_entry *
1139 __ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1142 struct ftrace_func_entry *entry;
1143 struct hlist_head *hhd;
1145 key = ftrace_hash_key(hash, ip);
1146 hhd = &hash->buckets[key];
1148 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1149 if (entry->ip == ip)
1156 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1157 * @hash: The hash to look at
1158 * @ip: The instruction pointer to test
1160 * Search a given @hash to see if a given instruction pointer (@ip)
1163 * Returns the entry that holds the @ip if found. NULL otherwise.
1165 struct ftrace_func_entry *
1166 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1168 if (ftrace_hash_empty(hash))
1171 return __ftrace_lookup_ip(hash, ip);
1174 static void __add_hash_entry(struct ftrace_hash *hash,
1175 struct ftrace_func_entry *entry)
1177 struct hlist_head *hhd;
1180 key = ftrace_hash_key(hash, entry->ip);
1181 hhd = &hash->buckets[key];
1182 hlist_add_head(&entry->hlist, hhd);
1186 static struct ftrace_func_entry *
1187 add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1189 struct ftrace_func_entry *entry;
1191 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1196 __add_hash_entry(hash, entry);
1202 free_hash_entry(struct ftrace_hash *hash,
1203 struct ftrace_func_entry *entry)
1205 hlist_del(&entry->hlist);
1211 remove_hash_entry(struct ftrace_hash *hash,
1212 struct ftrace_func_entry *entry)
1214 hlist_del_rcu(&entry->hlist);
1218 static void ftrace_hash_clear(struct ftrace_hash *hash)
1220 struct hlist_head *hhd;
1221 struct hlist_node *tn;
1222 struct ftrace_func_entry *entry;
1223 int size = 1 << hash->size_bits;
1229 for (i = 0; i < size; i++) {
1230 hhd = &hash->buckets[i];
1231 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1232 free_hash_entry(hash, entry);
1234 FTRACE_WARN_ON(hash->count);
1237 static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1239 list_del(&ftrace_mod->list);
1240 kfree(ftrace_mod->module);
1241 kfree(ftrace_mod->func);
1245 static void clear_ftrace_mod_list(struct list_head *head)
1247 struct ftrace_mod_load *p, *n;
1249 /* stack tracer isn't supported yet */
1253 mutex_lock(&ftrace_lock);
1254 list_for_each_entry_safe(p, n, head, list)
1256 mutex_unlock(&ftrace_lock);
1259 static void free_ftrace_hash(struct ftrace_hash *hash)
1261 if (!hash || hash == EMPTY_HASH)
1263 ftrace_hash_clear(hash);
1264 kfree(hash->buckets);
1268 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1270 struct ftrace_hash *hash;
1272 hash = container_of(rcu, struct ftrace_hash, rcu);
1273 free_ftrace_hash(hash);
1276 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1278 if (!hash || hash == EMPTY_HASH)
1280 call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
1284 * ftrace_free_filter - remove all filters for an ftrace_ops
1285 * @ops - the ops to remove the filters from
1287 void ftrace_free_filter(struct ftrace_ops *ops)
1289 ftrace_ops_init(ops);
1290 free_ftrace_hash(ops->func_hash->filter_hash);
1291 free_ftrace_hash(ops->func_hash->notrace_hash);
1293 EXPORT_SYMBOL_GPL(ftrace_free_filter);
1295 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1297 struct ftrace_hash *hash;
1300 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1304 size = 1 << size_bits;
1305 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1307 if (!hash->buckets) {
1312 hash->size_bits = size_bits;
1318 static int ftrace_add_mod(struct trace_array *tr,
1319 const char *func, const char *module,
1322 struct ftrace_mod_load *ftrace_mod;
1323 struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1325 ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1329 INIT_LIST_HEAD(&ftrace_mod->list);
1330 ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1331 ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1332 ftrace_mod->enable = enable;
1334 if (!ftrace_mod->func || !ftrace_mod->module)
1337 list_add(&ftrace_mod->list, mod_head);
1342 free_ftrace_mod(ftrace_mod);
1347 static struct ftrace_hash *
1348 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1350 struct ftrace_func_entry *entry;
1351 struct ftrace_hash *new_hash;
1355 new_hash = alloc_ftrace_hash(size_bits);
1360 new_hash->flags = hash->flags;
1363 if (ftrace_hash_empty(hash))
1366 size = 1 << hash->size_bits;
1367 for (i = 0; i < size; i++) {
1368 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1369 if (add_hash_entry(new_hash, entry->ip) == NULL)
1374 FTRACE_WARN_ON(new_hash->count != hash->count);
1379 free_ftrace_hash(new_hash);
1384 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1386 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1388 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1389 struct ftrace_hash *new_hash);
1391 static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size)
1393 struct ftrace_func_entry *entry;
1394 struct ftrace_hash *new_hash;
1395 struct hlist_head *hhd;
1396 struct hlist_node *tn;
1401 * Use around half the size (max bit of it), but
1402 * a minimum of 2 is fine (as size of 0 or 1 both give 1 for bits).
1404 bits = fls(size / 2);
1406 /* Don't allocate too much */
1407 if (bits > FTRACE_HASH_MAX_BITS)
1408 bits = FTRACE_HASH_MAX_BITS;
1410 new_hash = alloc_ftrace_hash(bits);
1414 new_hash->flags = src->flags;
1416 size = 1 << src->size_bits;
1417 for (i = 0; i < size; i++) {
1418 hhd = &src->buckets[i];
1419 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1420 remove_hash_entry(src, entry);
1421 __add_hash_entry(new_hash, entry);
1427 static struct ftrace_hash *
1428 __ftrace_hash_move(struct ftrace_hash *src)
1430 int size = src->count;
1433 * If the new source is empty, just return the empty_hash.
1435 if (ftrace_hash_empty(src))
1438 return dup_hash(src, size);
1442 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1443 struct ftrace_hash **dst, struct ftrace_hash *src)
1445 struct ftrace_hash *new_hash;
1448 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1449 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1452 new_hash = __ftrace_hash_move(src);
1456 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1458 /* IPMODIFY should be updated only when filter_hash updating */
1459 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1461 free_ftrace_hash(new_hash);
1467 * Remove the current set, update the hash and add
1470 ftrace_hash_rec_disable_modify(ops, enable);
1472 rcu_assign_pointer(*dst, new_hash);
1474 ftrace_hash_rec_enable_modify(ops, enable);
1479 static bool hash_contains_ip(unsigned long ip,
1480 struct ftrace_ops_hash *hash)
1483 * The function record is a match if it exists in the filter
1484 * hash and not in the notrace hash. Note, an empty hash is
1485 * considered a match for the filter hash, but an empty
1486 * notrace hash is considered not in the notrace hash.
1488 return (ftrace_hash_empty(hash->filter_hash) ||
1489 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1490 (ftrace_hash_empty(hash->notrace_hash) ||
1491 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1495 * Test the hashes for this ops to see if we want to call
1496 * the ops->func or not.
1498 * It's a match if the ip is in the ops->filter_hash or
1499 * the filter_hash does not exist or is empty,
1501 * the ip is not in the ops->notrace_hash.
1503 * This needs to be called with preemption disabled as
1504 * the hashes are freed with call_rcu().
1507 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1509 struct ftrace_ops_hash hash;
1512 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1514 * There's a small race when adding ops that the ftrace handler
1515 * that wants regs, may be called without them. We can not
1516 * allow that handler to be called if regs is NULL.
1518 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1522 rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1523 rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1525 if (hash_contains_ip(ip, &hash))
1534 * This is a double for. Do not use 'break' to break out of the loop,
1535 * you must use a goto.
1537 #define do_for_each_ftrace_rec(pg, rec) \
1538 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1540 for (_____i = 0; _____i < pg->index; _____i++) { \
1541 rec = &pg->records[_____i];
1543 #define while_for_each_ftrace_rec() \
1548 static int ftrace_cmp_recs(const void *a, const void *b)
1550 const struct dyn_ftrace *key = a;
1551 const struct dyn_ftrace *rec = b;
1553 if (key->flags < rec->ip)
1555 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1560 static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
1562 struct ftrace_page *pg;
1563 struct dyn_ftrace *rec = NULL;
1564 struct dyn_ftrace key;
1567 key.flags = end; /* overload flags, as it is unsigned long */
1569 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1570 if (pg->index == 0 ||
1571 end < pg->records[0].ip ||
1572 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1574 rec = bsearch(&key, pg->records, pg->index,
1575 sizeof(struct dyn_ftrace),
1584 * ftrace_location_range - return the first address of a traced location
1585 * if it touches the given ip range
1586 * @start: start of range to search.
1587 * @end: end of range to search (inclusive). @end points to the last byte
1590 * Returns rec->ip if the related ftrace location is a least partly within
1591 * the given address range. That is, the first address of the instruction
1592 * that is either a NOP or call to the function tracer. It checks the ftrace
1593 * internal tables to determine if the address belongs or not.
1595 unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1597 struct dyn_ftrace *rec;
1599 rec = lookup_rec(start, end);
1607 * ftrace_location - return the ftrace location
1608 * @ip: the instruction pointer to check
1610 * If @ip matches the ftrace location, return @ip.
1611 * If @ip matches sym+0, return sym's ftrace location.
1612 * Otherwise, return 0.
1614 unsigned long ftrace_location(unsigned long ip)
1616 struct dyn_ftrace *rec;
1617 unsigned long offset;
1620 rec = lookup_rec(ip, ip);
1622 if (!kallsyms_lookup_size_offset(ip, &size, &offset))
1625 /* map sym+0 to __fentry__ */
1627 rec = lookup_rec(ip, ip + size - 1);
1638 * ftrace_text_reserved - return true if range contains an ftrace location
1639 * @start: start of range to search
1640 * @end: end of range to search (inclusive). @end points to the last byte to check.
1642 * Returns 1 if @start and @end contains a ftrace location.
1643 * That is, the instruction that is either a NOP or call to
1644 * the function tracer. It checks the ftrace internal tables to
1645 * determine if the address belongs or not.
1647 int ftrace_text_reserved(const void *start, const void *end)
1651 ret = ftrace_location_range((unsigned long)start,
1652 (unsigned long)end);
1657 /* Test if ops registered to this rec needs regs */
1658 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1660 struct ftrace_ops *ops;
1661 bool keep_regs = false;
1663 for (ops = ftrace_ops_list;
1664 ops != &ftrace_list_end; ops = ops->next) {
1665 /* pass rec in as regs to have non-NULL val */
1666 if (ftrace_ops_test(ops, rec->ip, rec)) {
1667 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1677 static struct ftrace_ops *
1678 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1679 static struct ftrace_ops *
1680 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude);
1681 static struct ftrace_ops *
1682 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1684 static bool skip_record(struct dyn_ftrace *rec)
1687 * At boot up, weak functions are set to disable. Function tracing
1688 * can be enabled before they are, and they still need to be disabled now.
1689 * If the record is disabled, still continue if it is marked as already
1690 * enabled (this is needed to keep the accounting working).
1692 return rec->flags & FTRACE_FL_DISABLED &&
1693 !(rec->flags & FTRACE_FL_ENABLED);
1696 static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1700 struct ftrace_hash *hash;
1701 struct ftrace_hash *other_hash;
1702 struct ftrace_page *pg;
1703 struct dyn_ftrace *rec;
1704 bool update = false;
1708 /* Only update if the ops has been registered */
1709 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1713 * In the filter_hash case:
1714 * If the count is zero, we update all records.
1715 * Otherwise we just update the items in the hash.
1717 * In the notrace_hash case:
1718 * We enable the update in the hash.
1719 * As disabling notrace means enabling the tracing,
1720 * and enabling notrace means disabling, the inc variable
1724 hash = ops->func_hash->filter_hash;
1725 other_hash = ops->func_hash->notrace_hash;
1726 if (ftrace_hash_empty(hash))
1730 hash = ops->func_hash->notrace_hash;
1731 other_hash = ops->func_hash->filter_hash;
1733 * If the notrace hash has no items,
1734 * then there's nothing to do.
1736 if (ftrace_hash_empty(hash))
1740 do_for_each_ftrace_rec(pg, rec) {
1741 int in_other_hash = 0;
1745 if (skip_record(rec))
1750 * Only the filter_hash affects all records.
1751 * Update if the record is not in the notrace hash.
1753 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1756 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1757 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1760 * If filter_hash is set, we want to match all functions
1761 * that are in the hash but not in the other hash.
1763 * If filter_hash is not set, then we are decrementing.
1764 * That means we match anything that is in the hash
1765 * and also in the other_hash. That is, we need to turn
1766 * off functions in the other hash because they are disabled
1769 if (filter_hash && in_hash && !in_other_hash)
1771 else if (!filter_hash && in_hash &&
1772 (in_other_hash || ftrace_hash_empty(other_hash)))
1780 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1783 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1784 rec->flags |= FTRACE_FL_DIRECT;
1787 * If there's only a single callback registered to a
1788 * function, and the ops has a trampoline registered
1789 * for it, then we can call it directly.
1791 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1792 rec->flags |= FTRACE_FL_TRAMP;
1795 * If we are adding another function callback
1796 * to this function, and the previous had a
1797 * custom trampoline in use, then we need to go
1798 * back to the default trampoline.
1800 rec->flags &= ~FTRACE_FL_TRAMP;
1803 * If any ops wants regs saved for this function
1804 * then all ops will get saved regs.
1806 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1807 rec->flags |= FTRACE_FL_REGS;
1809 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1814 * Only the internal direct_ops should have the
1815 * DIRECT flag set. Thus, if it is removing a
1816 * function, then that function should no longer
1819 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1820 rec->flags &= ~FTRACE_FL_DIRECT;
1823 * If the rec had REGS enabled and the ops that is
1824 * being removed had REGS set, then see if there is
1825 * still any ops for this record that wants regs.
1826 * If not, we can stop recording them.
1828 if (ftrace_rec_count(rec) > 0 &&
1829 rec->flags & FTRACE_FL_REGS &&
1830 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1831 if (!test_rec_ops_needs_regs(rec))
1832 rec->flags &= ~FTRACE_FL_REGS;
1836 * The TRAMP needs to be set only if rec count
1837 * is decremented to one, and the ops that is
1838 * left has a trampoline. As TRAMP can only be
1839 * enabled if there is only a single ops attached
1842 if (ftrace_rec_count(rec) == 1 &&
1843 ftrace_find_tramp_ops_any_other(rec, ops))
1844 rec->flags |= FTRACE_FL_TRAMP;
1846 rec->flags &= ~FTRACE_FL_TRAMP;
1849 * flags will be cleared in ftrace_check_record()
1850 * if rec count is zero.
1855 * If the rec has a single associated ops, and ops->func can be
1856 * called directly, allow the call site to call via the ops.
1858 if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS) &&
1859 ftrace_rec_count(rec) == 1 &&
1860 ftrace_ops_get_func(ops) == ops->func)
1861 rec->flags |= FTRACE_FL_CALL_OPS;
1863 rec->flags &= ~FTRACE_FL_CALL_OPS;
1867 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1868 update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1870 /* Shortcut, if we handled all records, we are done. */
1871 if (!all && count == hash->count)
1873 } while_for_each_ftrace_rec();
1878 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1881 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1884 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1887 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1890 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1891 int filter_hash, int inc)
1893 struct ftrace_ops *op;
1895 __ftrace_hash_rec_update(ops, filter_hash, inc);
1897 if (ops->func_hash != &global_ops.local_hash)
1901 * If the ops shares the global_ops hash, then we need to update
1902 * all ops that are enabled and use this hash.
1904 do_for_each_ftrace_op(op, ftrace_ops_list) {
1908 if (op->func_hash == &global_ops.local_hash)
1909 __ftrace_hash_rec_update(op, filter_hash, inc);
1910 } while_for_each_ftrace_op(op);
1913 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1916 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1919 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1922 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1926 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1927 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1928 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1929 * Note that old_hash and new_hash has below meanings
1930 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1931 * - If the hash is EMPTY_HASH, it hits nothing
1932 * - Anything else hits the recs which match the hash entries.
1934 * DIRECT ops does not have IPMODIFY flag, but we still need to check it
1935 * against functions with FTRACE_FL_IPMODIFY. If there is any overlap, call
1936 * ops_func(SHARE_IPMODIFY_SELF) to make sure current ops can share with
1937 * IPMODIFY. If ops_func(SHARE_IPMODIFY_SELF) returns non-zero, propagate
1938 * the return value to the caller and eventually to the owner of the DIRECT
1941 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1942 struct ftrace_hash *old_hash,
1943 struct ftrace_hash *new_hash)
1945 struct ftrace_page *pg;
1946 struct dyn_ftrace *rec, *end = NULL;
1948 bool is_ipmodify, is_direct;
1950 /* Only update if the ops has been registered */
1951 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1954 is_ipmodify = ops->flags & FTRACE_OPS_FL_IPMODIFY;
1955 is_direct = ops->flags & FTRACE_OPS_FL_DIRECT;
1957 /* neither IPMODIFY nor DIRECT, skip */
1958 if (!is_ipmodify && !is_direct)
1961 if (WARN_ON_ONCE(is_ipmodify && is_direct))
1965 * Since the IPMODIFY and DIRECT are very address sensitive
1966 * actions, we do not allow ftrace_ops to set all functions to new
1969 if (!new_hash || !old_hash)
1972 /* Update rec->flags */
1973 do_for_each_ftrace_rec(pg, rec) {
1975 if (rec->flags & FTRACE_FL_DISABLED)
1978 /* We need to update only differences of filter_hash */
1979 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1980 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1981 if (in_old == in_new)
1985 if (rec->flags & FTRACE_FL_IPMODIFY) {
1988 /* Cannot have two ipmodify on same rec */
1992 FTRACE_WARN_ON(rec->flags & FTRACE_FL_DIRECT);
1995 * Another ops with IPMODIFY is already
1996 * attached. We are now attaching a direct
1997 * ops. Run SHARE_IPMODIFY_SELF, to check
1998 * whether sharing is supported.
2002 ret = ops->ops_func(ops, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF);
2005 } else if (is_ipmodify) {
2006 rec->flags |= FTRACE_FL_IPMODIFY;
2008 } else if (is_ipmodify) {
2009 rec->flags &= ~FTRACE_FL_IPMODIFY;
2011 } while_for_each_ftrace_rec();
2018 /* Roll back what we did above */
2019 do_for_each_ftrace_rec(pg, rec) {
2021 if (rec->flags & FTRACE_FL_DISABLED)
2027 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
2028 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
2029 if (in_old == in_new)
2033 rec->flags &= ~FTRACE_FL_IPMODIFY;
2035 rec->flags |= FTRACE_FL_IPMODIFY;
2036 } while_for_each_ftrace_rec();
2042 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
2044 struct ftrace_hash *hash = ops->func_hash->filter_hash;
2046 if (ftrace_hash_empty(hash))
2049 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
2052 /* Disabling always succeeds */
2053 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
2055 struct ftrace_hash *hash = ops->func_hash->filter_hash;
2057 if (ftrace_hash_empty(hash))
2060 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
2063 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
2064 struct ftrace_hash *new_hash)
2066 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
2068 if (ftrace_hash_empty(old_hash))
2071 if (ftrace_hash_empty(new_hash))
2074 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
2077 static void print_ip_ins(const char *fmt, const unsigned char *p)
2079 char ins[MCOUNT_INSN_SIZE];
2081 if (copy_from_kernel_nofault(ins, p, MCOUNT_INSN_SIZE)) {
2082 printk(KERN_CONT "%s[FAULT] %px\n", fmt, p);
2086 printk(KERN_CONT "%s", fmt);
2087 pr_cont("%*phC", MCOUNT_INSN_SIZE, ins);
2090 enum ftrace_bug_type ftrace_bug_type;
2091 const void *ftrace_expected;
2093 static void print_bug_type(void)
2095 switch (ftrace_bug_type) {
2096 case FTRACE_BUG_UNKNOWN:
2098 case FTRACE_BUG_INIT:
2099 pr_info("Initializing ftrace call sites\n");
2101 case FTRACE_BUG_NOP:
2102 pr_info("Setting ftrace call site to NOP\n");
2104 case FTRACE_BUG_CALL:
2105 pr_info("Setting ftrace call site to call ftrace function\n");
2107 case FTRACE_BUG_UPDATE:
2108 pr_info("Updating ftrace call site to call a different ftrace function\n");
2114 * ftrace_bug - report and shutdown function tracer
2115 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2116 * @rec: The record that failed
2118 * The arch code that enables or disables the function tracing
2119 * can call ftrace_bug() when it has detected a problem in
2120 * modifying the code. @failed should be one of either:
2121 * EFAULT - if the problem happens on reading the @ip address
2122 * EINVAL - if what is read at @ip is not what was expected
2123 * EPERM - if the problem happens on writing to the @ip address
2125 void ftrace_bug(int failed, struct dyn_ftrace *rec)
2127 unsigned long ip = rec ? rec->ip : 0;
2129 pr_info("------------[ ftrace bug ]------------\n");
2133 pr_info("ftrace faulted on modifying ");
2134 print_ip_sym(KERN_INFO, ip);
2137 pr_info("ftrace failed to modify ");
2138 print_ip_sym(KERN_INFO, ip);
2139 print_ip_ins(" actual: ", (unsigned char *)ip);
2141 if (ftrace_expected) {
2142 print_ip_ins(" expected: ", ftrace_expected);
2147 pr_info("ftrace faulted on writing ");
2148 print_ip_sym(KERN_INFO, ip);
2151 pr_info("ftrace faulted on unknown error ");
2152 print_ip_sym(KERN_INFO, ip);
2156 struct ftrace_ops *ops = NULL;
2158 pr_info("ftrace record flags: %lx\n", rec->flags);
2159 pr_cont(" (%ld)%s%s", ftrace_rec_count(rec),
2160 rec->flags & FTRACE_FL_REGS ? " R" : " ",
2161 rec->flags & FTRACE_FL_CALL_OPS ? " O" : " ");
2162 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2163 ops = ftrace_find_tramp_ops_any(rec);
2166 pr_cont("\ttramp: %pS (%pS)",
2167 (void *)ops->trampoline,
2169 ops = ftrace_find_tramp_ops_next(rec, ops);
2172 pr_cont("\ttramp: ERROR!");
2175 ip = ftrace_get_addr_curr(rec);
2176 pr_cont("\n expected tramp: %lx\n", ip);
2179 FTRACE_WARN_ON_ONCE(1);
2182 static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2184 unsigned long flag = 0UL;
2186 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2188 if (skip_record(rec))
2189 return FTRACE_UPDATE_IGNORE;
2192 * If we are updating calls:
2194 * If the record has a ref count, then we need to enable it
2195 * because someone is using it.
2197 * Otherwise we make sure its disabled.
2199 * If we are disabling calls, then disable all records that
2202 if (enable && ftrace_rec_count(rec))
2203 flag = FTRACE_FL_ENABLED;
2206 * If enabling and the REGS flag does not match the REGS_EN, or
2207 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2208 * this record. Set flags to fail the compare against ENABLED.
2209 * Same for direct calls.
2212 if (!(rec->flags & FTRACE_FL_REGS) !=
2213 !(rec->flags & FTRACE_FL_REGS_EN))
2214 flag |= FTRACE_FL_REGS;
2216 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2217 !(rec->flags & FTRACE_FL_TRAMP_EN))
2218 flag |= FTRACE_FL_TRAMP;
2221 * Direct calls are special, as count matters.
2222 * We must test the record for direct, if the
2223 * DIRECT and DIRECT_EN do not match, but only
2224 * if the count is 1. That's because, if the
2225 * count is something other than one, we do not
2226 * want the direct enabled (it will be done via the
2227 * direct helper). But if DIRECT_EN is set, and
2228 * the count is not one, we need to clear it.
2231 if (ftrace_rec_count(rec) == 1) {
2232 if (!(rec->flags & FTRACE_FL_DIRECT) !=
2233 !(rec->flags & FTRACE_FL_DIRECT_EN))
2234 flag |= FTRACE_FL_DIRECT;
2235 } else if (rec->flags & FTRACE_FL_DIRECT_EN) {
2236 flag |= FTRACE_FL_DIRECT;
2240 * Ops calls are special, as count matters.
2241 * As with direct calls, they must only be enabled when count
2242 * is one, otherwise they'll be handled via the list ops.
2244 if (ftrace_rec_count(rec) == 1) {
2245 if (!(rec->flags & FTRACE_FL_CALL_OPS) !=
2246 !(rec->flags & FTRACE_FL_CALL_OPS_EN))
2247 flag |= FTRACE_FL_CALL_OPS;
2248 } else if (rec->flags & FTRACE_FL_CALL_OPS_EN) {
2249 flag |= FTRACE_FL_CALL_OPS;
2253 /* If the state of this record hasn't changed, then do nothing */
2254 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2255 return FTRACE_UPDATE_IGNORE;
2258 /* Save off if rec is being enabled (for return value) */
2259 flag ^= rec->flags & FTRACE_FL_ENABLED;
2262 rec->flags |= FTRACE_FL_ENABLED | FTRACE_FL_TOUCHED;
2263 if (flag & FTRACE_FL_REGS) {
2264 if (rec->flags & FTRACE_FL_REGS)
2265 rec->flags |= FTRACE_FL_REGS_EN;
2267 rec->flags &= ~FTRACE_FL_REGS_EN;
2269 if (flag & FTRACE_FL_TRAMP) {
2270 if (rec->flags & FTRACE_FL_TRAMP)
2271 rec->flags |= FTRACE_FL_TRAMP_EN;
2273 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2276 /* Keep track of anything that modifies the function */
2277 if (rec->flags & (FTRACE_FL_DIRECT | FTRACE_FL_IPMODIFY))
2278 rec->flags |= FTRACE_FL_MODIFIED;
2280 if (flag & FTRACE_FL_DIRECT) {
2282 * If there's only one user (direct_ops helper)
2283 * then we can call the direct function
2284 * directly (no ftrace trampoline).
2286 if (ftrace_rec_count(rec) == 1) {
2287 if (rec->flags & FTRACE_FL_DIRECT)
2288 rec->flags |= FTRACE_FL_DIRECT_EN;
2290 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2293 * Can only call directly if there's
2294 * only one callback to the function.
2296 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2300 if (flag & FTRACE_FL_CALL_OPS) {
2301 if (ftrace_rec_count(rec) == 1) {
2302 if (rec->flags & FTRACE_FL_CALL_OPS)
2303 rec->flags |= FTRACE_FL_CALL_OPS_EN;
2305 rec->flags &= ~FTRACE_FL_CALL_OPS_EN;
2308 * Can only call directly if there's
2309 * only one set of associated ops.
2311 rec->flags &= ~FTRACE_FL_CALL_OPS_EN;
2317 * If this record is being updated from a nop, then
2318 * return UPDATE_MAKE_CALL.
2320 * return UPDATE_MODIFY_CALL to tell the caller to convert
2321 * from the save regs, to a non-save regs function or
2322 * vice versa, or from a trampoline call.
2324 if (flag & FTRACE_FL_ENABLED) {
2325 ftrace_bug_type = FTRACE_BUG_CALL;
2326 return FTRACE_UPDATE_MAKE_CALL;
2329 ftrace_bug_type = FTRACE_BUG_UPDATE;
2330 return FTRACE_UPDATE_MODIFY_CALL;
2334 /* If there's no more users, clear all flags */
2335 if (!ftrace_rec_count(rec))
2336 rec->flags &= FTRACE_NOCLEAR_FLAGS;
2339 * Just disable the record, but keep the ops TRAMP
2340 * and REGS states. The _EN flags must be disabled though.
2342 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2343 FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN |
2344 FTRACE_FL_CALL_OPS_EN);
2347 ftrace_bug_type = FTRACE_BUG_NOP;
2348 return FTRACE_UPDATE_MAKE_NOP;
2352 * ftrace_update_record - set a record that now is tracing or not
2353 * @rec: the record to update
2354 * @enable: set to true if the record is tracing, false to force disable
2356 * The records that represent all functions that can be traced need
2357 * to be updated when tracing has been enabled.
2359 int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2361 return ftrace_check_record(rec, enable, true);
2365 * ftrace_test_record - check if the record has been enabled or not
2366 * @rec: the record to test
2367 * @enable: set to true to check if enabled, false if it is disabled
2369 * The arch code may need to test if a record is already set to
2370 * tracing to determine how to modify the function code that it
2373 int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2375 return ftrace_check_record(rec, enable, false);
2378 static struct ftrace_ops *
2379 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2381 struct ftrace_ops *op;
2382 unsigned long ip = rec->ip;
2384 do_for_each_ftrace_op(op, ftrace_ops_list) {
2386 if (!op->trampoline)
2389 if (hash_contains_ip(ip, op->func_hash))
2391 } while_for_each_ftrace_op(op);
2396 static struct ftrace_ops *
2397 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude)
2399 struct ftrace_ops *op;
2400 unsigned long ip = rec->ip;
2402 do_for_each_ftrace_op(op, ftrace_ops_list) {
2404 if (op == op_exclude || !op->trampoline)
2407 if (hash_contains_ip(ip, op->func_hash))
2409 } while_for_each_ftrace_op(op);
2414 static struct ftrace_ops *
2415 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2416 struct ftrace_ops *op)
2418 unsigned long ip = rec->ip;
2420 while_for_each_ftrace_op(op) {
2422 if (!op->trampoline)
2425 if (hash_contains_ip(ip, op->func_hash))
2432 static struct ftrace_ops *
2433 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2435 struct ftrace_ops *op;
2436 unsigned long ip = rec->ip;
2439 * Need to check removed ops first.
2440 * If they are being removed, and this rec has a tramp,
2441 * and this rec is in the ops list, then it would be the
2442 * one with the tramp.
2445 if (hash_contains_ip(ip, &removed_ops->old_hash))
2450 * Need to find the current trampoline for a rec.
2451 * Now, a trampoline is only attached to a rec if there
2452 * was a single 'ops' attached to it. But this can be called
2453 * when we are adding another op to the rec or removing the
2454 * current one. Thus, if the op is being added, we can
2455 * ignore it because it hasn't attached itself to the rec
2458 * If an ops is being modified (hooking to different functions)
2459 * then we don't care about the new functions that are being
2460 * added, just the old ones (that are probably being removed).
2462 * If we are adding an ops to a function that already is using
2463 * a trampoline, it needs to be removed (trampolines are only
2464 * for single ops connected), then an ops that is not being
2465 * modified also needs to be checked.
2467 do_for_each_ftrace_op(op, ftrace_ops_list) {
2469 if (!op->trampoline)
2473 * If the ops is being added, it hasn't gotten to
2474 * the point to be removed from this tree yet.
2476 if (op->flags & FTRACE_OPS_FL_ADDING)
2481 * If the ops is being modified and is in the old
2482 * hash, then it is probably being removed from this
2485 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2486 hash_contains_ip(ip, &op->old_hash))
2489 * If the ops is not being added or modified, and it's
2490 * in its normal filter hash, then this must be the one
2493 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2494 hash_contains_ip(ip, op->func_hash))
2497 } while_for_each_ftrace_op(op);
2502 static struct ftrace_ops *
2503 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2505 struct ftrace_ops *op;
2506 unsigned long ip = rec->ip;
2508 do_for_each_ftrace_op(op, ftrace_ops_list) {
2509 /* pass rec in as regs to have non-NULL val */
2510 if (hash_contains_ip(ip, op->func_hash))
2512 } while_for_each_ftrace_op(op);
2518 ftrace_find_unique_ops(struct dyn_ftrace *rec)
2520 struct ftrace_ops *op, *found = NULL;
2521 unsigned long ip = rec->ip;
2523 do_for_each_ftrace_op(op, ftrace_ops_list) {
2525 if (hash_contains_ip(ip, op->func_hash)) {
2531 } while_for_each_ftrace_op(op);
2536 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
2537 /* Protected by rcu_tasks for reading, and direct_mutex for writing */
2538 static struct ftrace_hash __rcu *direct_functions = EMPTY_HASH;
2539 static DEFINE_MUTEX(direct_mutex);
2540 int ftrace_direct_func_count;
2543 * Search the direct_functions hash to see if the given instruction pointer
2544 * has a direct caller attached to it.
2546 unsigned long ftrace_find_rec_direct(unsigned long ip)
2548 struct ftrace_func_entry *entry;
2550 entry = __ftrace_lookup_ip(direct_functions, ip);
2554 return entry->direct;
2557 static void call_direct_funcs(unsigned long ip, unsigned long pip,
2558 struct ftrace_ops *ops, struct ftrace_regs *fregs)
2560 unsigned long addr = READ_ONCE(ops->direct_call);
2565 arch_ftrace_set_direct_caller(fregs, addr);
2567 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
2570 * ftrace_get_addr_new - Get the call address to set to
2571 * @rec: The ftrace record descriptor
2573 * If the record has the FTRACE_FL_REGS set, that means that it
2574 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2575 * is not set, then it wants to convert to the normal callback.
2577 * Returns the address of the trampoline to set to
2579 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2581 struct ftrace_ops *ops;
2584 if ((rec->flags & FTRACE_FL_DIRECT) &&
2585 (ftrace_rec_count(rec) == 1)) {
2586 addr = ftrace_find_rec_direct(rec->ip);
2592 /* Trampolines take precedence over regs */
2593 if (rec->flags & FTRACE_FL_TRAMP) {
2594 ops = ftrace_find_tramp_ops_new(rec);
2595 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2596 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2597 (void *)rec->ip, (void *)rec->ip, rec->flags);
2598 /* Ftrace is shutting down, return anything */
2599 return (unsigned long)FTRACE_ADDR;
2601 return ops->trampoline;
2604 if (rec->flags & FTRACE_FL_REGS)
2605 return (unsigned long)FTRACE_REGS_ADDR;
2607 return (unsigned long)FTRACE_ADDR;
2611 * ftrace_get_addr_curr - Get the call address that is already there
2612 * @rec: The ftrace record descriptor
2614 * The FTRACE_FL_REGS_EN is set when the record already points to
2615 * a function that saves all the regs. Basically the '_EN' version
2616 * represents the current state of the function.
2618 * Returns the address of the trampoline that is currently being called
2620 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2622 struct ftrace_ops *ops;
2625 /* Direct calls take precedence over trampolines */
2626 if (rec->flags & FTRACE_FL_DIRECT_EN) {
2627 addr = ftrace_find_rec_direct(rec->ip);
2633 /* Trampolines take precedence over regs */
2634 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2635 ops = ftrace_find_tramp_ops_curr(rec);
2636 if (FTRACE_WARN_ON(!ops)) {
2637 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2638 (void *)rec->ip, (void *)rec->ip);
2639 /* Ftrace is shutting down, return anything */
2640 return (unsigned long)FTRACE_ADDR;
2642 return ops->trampoline;
2645 if (rec->flags & FTRACE_FL_REGS_EN)
2646 return (unsigned long)FTRACE_REGS_ADDR;
2648 return (unsigned long)FTRACE_ADDR;
2652 __ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2654 unsigned long ftrace_old_addr;
2655 unsigned long ftrace_addr;
2658 ftrace_addr = ftrace_get_addr_new(rec);
2660 /* This needs to be done before we call ftrace_update_record */
2661 ftrace_old_addr = ftrace_get_addr_curr(rec);
2663 ret = ftrace_update_record(rec, enable);
2665 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2668 case FTRACE_UPDATE_IGNORE:
2671 case FTRACE_UPDATE_MAKE_CALL:
2672 ftrace_bug_type = FTRACE_BUG_CALL;
2673 return ftrace_make_call(rec, ftrace_addr);
2675 case FTRACE_UPDATE_MAKE_NOP:
2676 ftrace_bug_type = FTRACE_BUG_NOP;
2677 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2679 case FTRACE_UPDATE_MODIFY_CALL:
2680 ftrace_bug_type = FTRACE_BUG_UPDATE;
2681 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2684 return -1; /* unknown ftrace bug */
2687 void __weak ftrace_replace_code(int mod_flags)
2689 struct dyn_ftrace *rec;
2690 struct ftrace_page *pg;
2691 bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2692 int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2695 if (unlikely(ftrace_disabled))
2698 do_for_each_ftrace_rec(pg, rec) {
2700 if (skip_record(rec))
2703 failed = __ftrace_replace_code(rec, enable);
2705 ftrace_bug(failed, rec);
2706 /* Stop processing */
2711 } while_for_each_ftrace_rec();
2714 struct ftrace_rec_iter {
2715 struct ftrace_page *pg;
2720 * ftrace_rec_iter_start - start up iterating over traced functions
2722 * Returns an iterator handle that is used to iterate over all
2723 * the records that represent address locations where functions
2726 * May return NULL if no records are available.
2728 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2731 * We only use a single iterator.
2732 * Protected by the ftrace_lock mutex.
2734 static struct ftrace_rec_iter ftrace_rec_iter;
2735 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2737 iter->pg = ftrace_pages_start;
2740 /* Could have empty pages */
2741 while (iter->pg && !iter->pg->index)
2742 iter->pg = iter->pg->next;
2751 * ftrace_rec_iter_next - get the next record to process.
2752 * @iter: The handle to the iterator.
2754 * Returns the next iterator after the given iterator @iter.
2756 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2760 if (iter->index >= iter->pg->index) {
2761 iter->pg = iter->pg->next;
2764 /* Could have empty pages */
2765 while (iter->pg && !iter->pg->index)
2766 iter->pg = iter->pg->next;
2776 * ftrace_rec_iter_record - get the record at the iterator location
2777 * @iter: The current iterator location
2779 * Returns the record that the current @iter is at.
2781 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2783 return &iter->pg->records[iter->index];
2787 ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
2791 if (unlikely(ftrace_disabled))
2794 ret = ftrace_init_nop(mod, rec);
2796 ftrace_bug_type = FTRACE_BUG_INIT;
2797 ftrace_bug(ret, rec);
2804 * archs can override this function if they must do something
2805 * before the modifying code is performed.
2807 void __weak ftrace_arch_code_modify_prepare(void)
2812 * archs can override this function if they must do something
2813 * after the modifying code is performed.
2815 void __weak ftrace_arch_code_modify_post_process(void)
2819 static int update_ftrace_func(ftrace_func_t func)
2821 static ftrace_func_t save_func;
2823 /* Avoid updating if it hasn't changed */
2824 if (func == save_func)
2829 return ftrace_update_ftrace_func(func);
2832 void ftrace_modify_all_code(int command)
2834 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2838 if (command & FTRACE_MAY_SLEEP)
2839 mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2842 * If the ftrace_caller calls a ftrace_ops func directly,
2843 * we need to make sure that it only traces functions it
2844 * expects to trace. When doing the switch of functions,
2845 * we need to update to the ftrace_ops_list_func first
2846 * before the transition between old and new calls are set,
2847 * as the ftrace_ops_list_func will check the ops hashes
2848 * to make sure the ops are having the right functions
2852 err = update_ftrace_func(ftrace_ops_list_func);
2853 if (FTRACE_WARN_ON(err))
2857 if (command & FTRACE_UPDATE_CALLS)
2858 ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2859 else if (command & FTRACE_DISABLE_CALLS)
2860 ftrace_replace_code(mod_flags);
2862 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2863 function_trace_op = set_function_trace_op;
2865 /* If irqs are disabled, we are in stop machine */
2866 if (!irqs_disabled())
2867 smp_call_function(ftrace_sync_ipi, NULL, 1);
2868 err = update_ftrace_func(ftrace_trace_function);
2869 if (FTRACE_WARN_ON(err))
2873 if (command & FTRACE_START_FUNC_RET)
2874 err = ftrace_enable_ftrace_graph_caller();
2875 else if (command & FTRACE_STOP_FUNC_RET)
2876 err = ftrace_disable_ftrace_graph_caller();
2877 FTRACE_WARN_ON(err);
2880 static int __ftrace_modify_code(void *data)
2882 int *command = data;
2884 ftrace_modify_all_code(*command);
2890 * ftrace_run_stop_machine - go back to the stop machine method
2891 * @command: The command to tell ftrace what to do
2893 * If an arch needs to fall back to the stop machine method, the
2894 * it can call this function.
2896 void ftrace_run_stop_machine(int command)
2898 stop_machine(__ftrace_modify_code, &command, NULL);
2902 * arch_ftrace_update_code - modify the code to trace or not trace
2903 * @command: The command that needs to be done
2905 * Archs can override this function if it does not need to
2906 * run stop_machine() to modify code.
2908 void __weak arch_ftrace_update_code(int command)
2910 ftrace_run_stop_machine(command);
2913 static void ftrace_run_update_code(int command)
2915 ftrace_arch_code_modify_prepare();
2918 * By default we use stop_machine() to modify the code.
2919 * But archs can do what ever they want as long as it
2920 * is safe. The stop_machine() is the safest, but also
2921 * produces the most overhead.
2923 arch_ftrace_update_code(command);
2925 ftrace_arch_code_modify_post_process();
2928 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2929 struct ftrace_ops_hash *old_hash)
2931 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2932 ops->old_hash.filter_hash = old_hash->filter_hash;
2933 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2934 ftrace_run_update_code(command);
2935 ops->old_hash.filter_hash = NULL;
2936 ops->old_hash.notrace_hash = NULL;
2937 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2940 static ftrace_func_t saved_ftrace_func;
2941 static int ftrace_start_up;
2943 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2947 /* List of trace_ops that have allocated trampolines */
2948 static LIST_HEAD(ftrace_ops_trampoline_list);
2950 static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops *ops)
2952 lockdep_assert_held(&ftrace_lock);
2953 list_add_rcu(&ops->list, &ftrace_ops_trampoline_list);
2956 static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops)
2958 lockdep_assert_held(&ftrace_lock);
2959 list_del_rcu(&ops->list);
2964 * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols
2965 * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is
2968 #define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace"
2969 #define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"
2971 static void ftrace_trampoline_free(struct ftrace_ops *ops)
2973 if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
2976 * Record the text poke event before the ksymbol unregister
2979 perf_event_text_poke((void *)ops->trampoline,
2980 (void *)ops->trampoline,
2981 ops->trampoline_size, NULL, 0);
2982 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
2983 ops->trampoline, ops->trampoline_size,
2984 true, FTRACE_TRAMPOLINE_SYM);
2985 /* Remove from kallsyms after the perf events */
2986 ftrace_remove_trampoline_from_kallsyms(ops);
2989 arch_ftrace_trampoline_free(ops);
2992 static void ftrace_startup_enable(int command)
2994 if (saved_ftrace_func != ftrace_trace_function) {
2995 saved_ftrace_func = ftrace_trace_function;
2996 command |= FTRACE_UPDATE_TRACE_FUNC;
2999 if (!command || !ftrace_enabled)
3002 ftrace_run_update_code(command);
3005 static void ftrace_startup_all(int command)
3007 update_all_ops = true;
3008 ftrace_startup_enable(command);
3009 update_all_ops = false;
3012 int ftrace_startup(struct ftrace_ops *ops, int command)
3016 if (unlikely(ftrace_disabled))
3019 ret = __register_ftrace_function(ops);
3026 * Note that ftrace probes uses this to start up
3027 * and modify functions it will probe. But we still
3028 * set the ADDING flag for modification, as probes
3029 * do not have trampolines. If they add them in the
3030 * future, then the probes will need to distinguish
3031 * between adding and updating probes.
3033 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
3035 ret = ftrace_hash_ipmodify_enable(ops);
3037 /* Rollback registration process */
3038 __unregister_ftrace_function(ops);
3040 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
3041 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
3042 ftrace_trampoline_free(ops);
3046 if (ftrace_hash_rec_enable(ops, 1))
3047 command |= FTRACE_UPDATE_CALLS;
3049 ftrace_startup_enable(command);
3052 * If ftrace is in an undefined state, we just remove ops from list
3053 * to prevent the NULL pointer, instead of totally rolling it back and
3054 * free trampoline, because those actions could cause further damage.
3056 if (unlikely(ftrace_disabled)) {
3057 __unregister_ftrace_function(ops);
3061 ops->flags &= ~FTRACE_OPS_FL_ADDING;
3066 int ftrace_shutdown(struct ftrace_ops *ops, int command)
3070 if (unlikely(ftrace_disabled))
3073 ret = __unregister_ftrace_function(ops);
3079 * Just warn in case of unbalance, no need to kill ftrace, it's not
3080 * critical but the ftrace_call callers may be never nopped again after
3081 * further ftrace uses.
3083 WARN_ON_ONCE(ftrace_start_up < 0);
3085 /* Disabling ipmodify never fails */
3086 ftrace_hash_ipmodify_disable(ops);
3088 if (ftrace_hash_rec_disable(ops, 1))
3089 command |= FTRACE_UPDATE_CALLS;
3091 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
3093 if (saved_ftrace_func != ftrace_trace_function) {
3094 saved_ftrace_func = ftrace_trace_function;
3095 command |= FTRACE_UPDATE_TRACE_FUNC;
3098 if (!command || !ftrace_enabled)
3102 * If the ops uses a trampoline, then it needs to be
3103 * tested first on update.
3105 ops->flags |= FTRACE_OPS_FL_REMOVING;
3108 /* The trampoline logic checks the old hashes */
3109 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
3110 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
3112 ftrace_run_update_code(command);
3115 * If there's no more ops registered with ftrace, run a
3116 * sanity check to make sure all rec flags are cleared.
3118 if (rcu_dereference_protected(ftrace_ops_list,
3119 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
3120 struct ftrace_page *pg;
3121 struct dyn_ftrace *rec;
3123 do_for_each_ftrace_rec(pg, rec) {
3124 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_NOCLEAR_FLAGS))
3125 pr_warn(" %pS flags:%lx\n",
3126 (void *)rec->ip, rec->flags);
3127 } while_for_each_ftrace_rec();
3130 ops->old_hash.filter_hash = NULL;
3131 ops->old_hash.notrace_hash = NULL;
3134 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
3138 * Dynamic ops may be freed, we must make sure that all
3139 * callers are done before leaving this function.
3141 if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
3143 * We need to do a hard force of sched synchronization.
3144 * This is because we use preempt_disable() to do RCU, but
3145 * the function tracers can be called where RCU is not watching
3146 * (like before user_exit()). We can not rely on the RCU
3147 * infrastructure to do the synchronization, thus we must do it
3150 synchronize_rcu_tasks_rude();
3153 * When the kernel is preemptive, tasks can be preempted
3154 * while on a ftrace trampoline. Just scheduling a task on
3155 * a CPU is not good enough to flush them. Calling
3156 * synchronize_rcu_tasks() will wait for those tasks to
3157 * execute and either schedule voluntarily or enter user space.
3159 if (IS_ENABLED(CONFIG_PREEMPTION))
3160 synchronize_rcu_tasks();
3162 ftrace_trampoline_free(ops);
3168 static u64 ftrace_update_time;
3169 unsigned long ftrace_update_tot_cnt;
3170 unsigned long ftrace_number_of_pages;
3171 unsigned long ftrace_number_of_groups;
3173 static inline int ops_traces_mod(struct ftrace_ops *ops)
3176 * Filter_hash being empty will default to trace module.
3177 * But notrace hash requires a test of individual module functions.
3179 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
3180 ftrace_hash_empty(ops->func_hash->notrace_hash);
3183 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
3185 bool init_nop = ftrace_need_init_nop();
3186 struct ftrace_page *pg;
3187 struct dyn_ftrace *p;
3189 unsigned long update_cnt = 0;
3190 unsigned long rec_flags = 0;
3193 start = ftrace_now(raw_smp_processor_id());
3196 * When a module is loaded, this function is called to convert
3197 * the calls to mcount in its text to nops, and also to create
3198 * an entry in the ftrace data. Now, if ftrace is activated
3199 * after this call, but before the module sets its text to
3200 * read-only, the modification of enabling ftrace can fail if
3201 * the read-only is done while ftrace is converting the calls.
3202 * To prevent this, the module's records are set as disabled
3203 * and will be enabled after the call to set the module's text
3207 rec_flags |= FTRACE_FL_DISABLED;
3209 for (pg = new_pgs; pg; pg = pg->next) {
3211 for (i = 0; i < pg->index; i++) {
3213 /* If something went wrong, bail without enabling anything */
3214 if (unlikely(ftrace_disabled))
3217 p = &pg->records[i];
3218 p->flags = rec_flags;
3221 * Do the initial record conversion from mcount jump
3222 * to the NOP instructions.
3224 if (init_nop && !ftrace_nop_initialize(mod, p))
3231 stop = ftrace_now(raw_smp_processor_id());
3232 ftrace_update_time = stop - start;
3233 ftrace_update_tot_cnt += update_cnt;
3238 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3244 if (WARN_ON(!count))
3247 /* We want to fill as much as possible, with no empty pages */
3248 pages = DIV_ROUND_UP(count, ENTRIES_PER_PAGE);
3249 order = fls(pages) - 1;
3252 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3255 /* if we can't allocate this size, try something smaller */
3262 ftrace_number_of_pages += 1 << order;
3263 ftrace_number_of_groups++;
3265 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3274 static void ftrace_free_pages(struct ftrace_page *pages)
3276 struct ftrace_page *pg = pages;
3280 free_pages((unsigned long)pg->records, pg->order);
3281 ftrace_number_of_pages -= 1 << pg->order;
3286 ftrace_number_of_groups--;
3290 static struct ftrace_page *
3291 ftrace_allocate_pages(unsigned long num_to_init)
3293 struct ftrace_page *start_pg;
3294 struct ftrace_page *pg;
3300 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3305 * Try to allocate as much as possible in one continues
3306 * location that fills in all of the space. We want to
3307 * waste as little space as possible.
3310 cnt = ftrace_allocate_records(pg, num_to_init);
3318 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3328 ftrace_free_pages(start_pg);
3329 pr_info("ftrace: FAILED to allocate memory for functions\n");
3333 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3335 struct ftrace_iterator {
3339 struct ftrace_page *pg;
3340 struct dyn_ftrace *func;
3341 struct ftrace_func_probe *probe;
3342 struct ftrace_func_entry *probe_entry;
3343 struct trace_parser parser;
3344 struct ftrace_hash *hash;
3345 struct ftrace_ops *ops;
3346 struct trace_array *tr;
3347 struct list_head *mod_list;
3354 t_probe_next(struct seq_file *m, loff_t *pos)
3356 struct ftrace_iterator *iter = m->private;
3357 struct trace_array *tr = iter->ops->private;
3358 struct list_head *func_probes;
3359 struct ftrace_hash *hash;
3360 struct list_head *next;
3361 struct hlist_node *hnd = NULL;
3362 struct hlist_head *hhd;
3371 func_probes = &tr->func_probes;
3372 if (list_empty(func_probes))
3376 next = func_probes->next;
3377 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3380 if (iter->probe_entry)
3381 hnd = &iter->probe_entry->hlist;
3383 hash = iter->probe->ops.func_hash->filter_hash;
3386 * A probe being registered may temporarily have an empty hash
3387 * and it's at the end of the func_probes list.
3389 if (!hash || hash == EMPTY_HASH)
3392 size = 1 << hash->size_bits;
3395 if (iter->pidx >= size) {
3396 if (iter->probe->list.next == func_probes)
3398 next = iter->probe->list.next;
3399 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3400 hash = iter->probe->ops.func_hash->filter_hash;
3401 size = 1 << hash->size_bits;
3405 hhd = &hash->buckets[iter->pidx];
3407 if (hlist_empty(hhd)) {
3423 if (WARN_ON_ONCE(!hnd))
3426 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3431 static void *t_probe_start(struct seq_file *m, loff_t *pos)
3433 struct ftrace_iterator *iter = m->private;
3437 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3440 if (iter->mod_pos > *pos)
3444 iter->probe_entry = NULL;
3446 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3447 p = t_probe_next(m, &l);
3454 /* Only set this if we have an item */
3455 iter->flags |= FTRACE_ITER_PROBE;
3461 t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3463 struct ftrace_func_entry *probe_entry;
3464 struct ftrace_probe_ops *probe_ops;
3465 struct ftrace_func_probe *probe;
3467 probe = iter->probe;
3468 probe_entry = iter->probe_entry;
3470 if (WARN_ON_ONCE(!probe || !probe_entry))
3473 probe_ops = probe->probe_ops;
3475 if (probe_ops->print)
3476 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3478 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3479 (void *)probe_ops->func);
3485 t_mod_next(struct seq_file *m, loff_t *pos)
3487 struct ftrace_iterator *iter = m->private;
3488 struct trace_array *tr = iter->tr;
3493 iter->mod_list = iter->mod_list->next;
3495 if (iter->mod_list == &tr->mod_trace ||
3496 iter->mod_list == &tr->mod_notrace) {
3497 iter->flags &= ~FTRACE_ITER_MOD;
3501 iter->mod_pos = *pos;
3506 static void *t_mod_start(struct seq_file *m, loff_t *pos)
3508 struct ftrace_iterator *iter = m->private;
3512 if (iter->func_pos > *pos)
3515 iter->mod_pos = iter->func_pos;
3517 /* probes are only available if tr is set */
3521 for (l = 0; l <= (*pos - iter->func_pos); ) {
3522 p = t_mod_next(m, &l);
3527 iter->flags &= ~FTRACE_ITER_MOD;
3528 return t_probe_start(m, pos);
3531 /* Only set this if we have an item */
3532 iter->flags |= FTRACE_ITER_MOD;
3538 t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3540 struct ftrace_mod_load *ftrace_mod;
3541 struct trace_array *tr = iter->tr;
3543 if (WARN_ON_ONCE(!iter->mod_list) ||
3544 iter->mod_list == &tr->mod_trace ||
3545 iter->mod_list == &tr->mod_notrace)
3548 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3550 if (ftrace_mod->func)
3551 seq_printf(m, "%s", ftrace_mod->func);
3555 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3561 t_func_next(struct seq_file *m, loff_t *pos)
3563 struct ftrace_iterator *iter = m->private;
3564 struct dyn_ftrace *rec = NULL;
3569 if (iter->idx >= iter->pg->index) {
3570 if (iter->pg->next) {
3571 iter->pg = iter->pg->next;
3576 rec = &iter->pg->records[iter->idx++];
3577 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3578 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3580 ((iter->flags & FTRACE_ITER_ENABLED) &&
3581 !(rec->flags & FTRACE_FL_ENABLED)) ||
3583 ((iter->flags & FTRACE_ITER_TOUCHED) &&
3584 !(rec->flags & FTRACE_FL_TOUCHED))) {
3594 iter->pos = iter->func_pos = *pos;
3601 t_next(struct seq_file *m, void *v, loff_t *pos)
3603 struct ftrace_iterator *iter = m->private;
3604 loff_t l = *pos; /* t_probe_start() must use original pos */
3607 if (unlikely(ftrace_disabled))
3610 if (iter->flags & FTRACE_ITER_PROBE)
3611 return t_probe_next(m, pos);
3613 if (iter->flags & FTRACE_ITER_MOD)
3614 return t_mod_next(m, pos);
3616 if (iter->flags & FTRACE_ITER_PRINTALL) {
3617 /* next must increment pos, and t_probe_start does not */
3619 return t_mod_start(m, &l);
3622 ret = t_func_next(m, pos);
3625 return t_mod_start(m, &l);
3630 static void reset_iter_read(struct ftrace_iterator *iter)
3634 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3637 static void *t_start(struct seq_file *m, loff_t *pos)
3639 struct ftrace_iterator *iter = m->private;
3643 mutex_lock(&ftrace_lock);
3645 if (unlikely(ftrace_disabled))
3649 * If an lseek was done, then reset and start from beginning.
3651 if (*pos < iter->pos)
3652 reset_iter_read(iter);
3655 * For set_ftrace_filter reading, if we have the filter
3656 * off, we can short cut and just print out that all
3657 * functions are enabled.
3659 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3660 ftrace_hash_empty(iter->hash)) {
3661 iter->func_pos = 1; /* Account for the message */
3663 return t_mod_start(m, pos);
3664 iter->flags |= FTRACE_ITER_PRINTALL;
3665 /* reset in case of seek/pread */
3666 iter->flags &= ~FTRACE_ITER_PROBE;
3670 if (iter->flags & FTRACE_ITER_MOD)
3671 return t_mod_start(m, pos);
3674 * Unfortunately, we need to restart at ftrace_pages_start
3675 * every time we let go of the ftrace_mutex. This is because
3676 * those pointers can change without the lock.
3678 iter->pg = ftrace_pages_start;
3680 for (l = 0; l <= *pos; ) {
3681 p = t_func_next(m, &l);
3687 return t_mod_start(m, pos);
3692 static void t_stop(struct seq_file *m, void *p)
3694 mutex_unlock(&ftrace_lock);
3698 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3703 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3704 struct dyn_ftrace *rec)
3708 ptr = arch_ftrace_trampoline_func(ops, rec);
3710 seq_printf(m, " ->%pS", ptr);
3713 #ifdef FTRACE_MCOUNT_MAX_OFFSET
3715 * Weak functions can still have an mcount/fentry that is saved in
3716 * the __mcount_loc section. These can be detected by having a
3717 * symbol offset of greater than FTRACE_MCOUNT_MAX_OFFSET, as the
3718 * symbol found by kallsyms is not the function that the mcount/fentry
3719 * is part of. The offset is much greater in these cases.
3721 * Test the record to make sure that the ip points to a valid kallsyms
3722 * and if not, mark it disabled.
3724 static int test_for_valid_rec(struct dyn_ftrace *rec)
3726 char str[KSYM_SYMBOL_LEN];
3727 unsigned long offset;
3730 ret = kallsyms_lookup(rec->ip, NULL, &offset, NULL, str);
3732 /* Weak functions can cause invalid addresses */
3733 if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
3734 rec->flags |= FTRACE_FL_DISABLED;
3740 static struct workqueue_struct *ftrace_check_wq __initdata;
3741 static struct work_struct ftrace_check_work __initdata;
3744 * Scan all the mcount/fentry entries to make sure they are valid.
3746 static __init void ftrace_check_work_func(struct work_struct *work)
3748 struct ftrace_page *pg;
3749 struct dyn_ftrace *rec;
3751 mutex_lock(&ftrace_lock);
3752 do_for_each_ftrace_rec(pg, rec) {
3753 test_for_valid_rec(rec);
3754 } while_for_each_ftrace_rec();
3755 mutex_unlock(&ftrace_lock);
3758 static int __init ftrace_check_for_weak_functions(void)
3760 INIT_WORK(&ftrace_check_work, ftrace_check_work_func);
3762 ftrace_check_wq = alloc_workqueue("ftrace_check_wq", WQ_UNBOUND, 0);
3764 queue_work(ftrace_check_wq, &ftrace_check_work);
3768 static int __init ftrace_check_sync(void)
3770 /* Make sure the ftrace_check updates are finished */
3771 if (ftrace_check_wq)
3772 destroy_workqueue(ftrace_check_wq);
3776 late_initcall_sync(ftrace_check_sync);
3777 subsys_initcall(ftrace_check_for_weak_functions);
3779 static int print_rec(struct seq_file *m, unsigned long ip)
3781 unsigned long offset;
3782 char str[KSYM_SYMBOL_LEN];
3786 ret = kallsyms_lookup(ip, NULL, &offset, &modname, str);
3787 /* Weak functions can cause invalid addresses */
3788 if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
3789 snprintf(str, KSYM_SYMBOL_LEN, "%s_%ld",
3790 FTRACE_INVALID_FUNCTION, offset);
3796 seq_printf(m, " [%s]", modname);
3797 return ret == NULL ? -1 : 0;
3800 static inline int test_for_valid_rec(struct dyn_ftrace *rec)
3805 static inline int print_rec(struct seq_file *m, unsigned long ip)
3807 seq_printf(m, "%ps", (void *)ip);
3812 static int t_show(struct seq_file *m, void *v)
3814 struct ftrace_iterator *iter = m->private;
3815 struct dyn_ftrace *rec;
3817 if (iter->flags & FTRACE_ITER_PROBE)
3818 return t_probe_show(m, iter);
3820 if (iter->flags & FTRACE_ITER_MOD)
3821 return t_mod_show(m, iter);
3823 if (iter->flags & FTRACE_ITER_PRINTALL) {
3824 if (iter->flags & FTRACE_ITER_NOTRACE)
3825 seq_puts(m, "#### no functions disabled ####\n");
3827 seq_puts(m, "#### all functions enabled ####\n");
3836 if (iter->flags & FTRACE_ITER_ADDRS)
3837 seq_printf(m, "%lx ", rec->ip);
3839 if (print_rec(m, rec->ip)) {
3840 /* This should only happen when a rec is disabled */
3841 WARN_ON_ONCE(!(rec->flags & FTRACE_FL_DISABLED));
3846 if (iter->flags & (FTRACE_ITER_ENABLED | FTRACE_ITER_TOUCHED)) {
3847 struct ftrace_ops *ops;
3849 seq_printf(m, " (%ld)%s%s%s%s%s",
3850 ftrace_rec_count(rec),
3851 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3852 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ",
3853 rec->flags & FTRACE_FL_DIRECT ? " D" : " ",
3854 rec->flags & FTRACE_FL_CALL_OPS ? " O" : " ",
3855 rec->flags & FTRACE_FL_MODIFIED ? " M " : " ");
3856 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3857 ops = ftrace_find_tramp_ops_any(rec);
3860 seq_printf(m, "\ttramp: %pS (%pS)",
3861 (void *)ops->trampoline,
3863 add_trampoline_func(m, ops, rec);
3864 ops = ftrace_find_tramp_ops_next(rec, ops);
3867 seq_puts(m, "\ttramp: ERROR!");
3869 add_trampoline_func(m, NULL, rec);
3871 if (rec->flags & FTRACE_FL_CALL_OPS_EN) {
3872 ops = ftrace_find_unique_ops(rec);
3874 seq_printf(m, "\tops: %pS (%pS)",
3877 seq_puts(m, "\tops: ERROR!");
3880 if (rec->flags & FTRACE_FL_DIRECT) {
3881 unsigned long direct;
3883 direct = ftrace_find_rec_direct(rec->ip);
3885 seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
3894 static const struct seq_operations show_ftrace_seq_ops = {
3902 ftrace_avail_open(struct inode *inode, struct file *file)
3904 struct ftrace_iterator *iter;
3907 ret = security_locked_down(LOCKDOWN_TRACEFS);
3911 if (unlikely(ftrace_disabled))
3914 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3918 iter->pg = ftrace_pages_start;
3919 iter->ops = &global_ops;
3925 ftrace_enabled_open(struct inode *inode, struct file *file)
3927 struct ftrace_iterator *iter;
3930 * This shows us what functions are currently being
3931 * traced and by what. Not sure if we want lockdown
3932 * to hide such critical information for an admin.
3933 * Although, perhaps it can show information we don't
3934 * want people to see, but if something is tracing
3935 * something, we probably want to know about it.
3938 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3942 iter->pg = ftrace_pages_start;
3943 iter->flags = FTRACE_ITER_ENABLED;
3944 iter->ops = &global_ops;
3950 ftrace_touched_open(struct inode *inode, struct file *file)
3952 struct ftrace_iterator *iter;
3955 * This shows us what functions have ever been enabled
3956 * (traced, direct, patched, etc). Not sure if we want lockdown
3957 * to hide such critical information for an admin.
3958 * Although, perhaps it can show information we don't
3959 * want people to see, but if something had traced
3960 * something, we probably want to know about it.
3963 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3967 iter->pg = ftrace_pages_start;
3968 iter->flags = FTRACE_ITER_TOUCHED;
3969 iter->ops = &global_ops;
3975 ftrace_avail_addrs_open(struct inode *inode, struct file *file)
3977 struct ftrace_iterator *iter;
3980 ret = security_locked_down(LOCKDOWN_TRACEFS);
3984 if (unlikely(ftrace_disabled))
3987 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3991 iter->pg = ftrace_pages_start;
3992 iter->flags = FTRACE_ITER_ADDRS;
3993 iter->ops = &global_ops;
3999 * ftrace_regex_open - initialize function tracer filter files
4000 * @ops: The ftrace_ops that hold the hash filters
4001 * @flag: The type of filter to process
4002 * @inode: The inode, usually passed in to your open routine
4003 * @file: The file, usually passed in to your open routine
4005 * ftrace_regex_open() initializes the filter files for the
4006 * @ops. Depending on @flag it may process the filter hash or
4007 * the notrace hash of @ops. With this called from the open
4008 * routine, you can use ftrace_filter_write() for the write
4009 * routine if @flag has FTRACE_ITER_FILTER set, or
4010 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
4011 * tracing_lseek() should be used as the lseek routine, and
4012 * release must call ftrace_regex_release().
4015 ftrace_regex_open(struct ftrace_ops *ops, int flag,
4016 struct inode *inode, struct file *file)
4018 struct ftrace_iterator *iter;
4019 struct ftrace_hash *hash;
4020 struct list_head *mod_head;
4021 struct trace_array *tr = ops->private;
4024 ftrace_ops_init(ops);
4026 if (unlikely(ftrace_disabled))
4029 if (tracing_check_open_get_tr(tr))
4032 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
4036 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
4043 mutex_lock(&ops->func_hash->regex_lock);
4045 if (flag & FTRACE_ITER_NOTRACE) {
4046 hash = ops->func_hash->notrace_hash;
4047 mod_head = tr ? &tr->mod_notrace : NULL;
4049 hash = ops->func_hash->filter_hash;
4050 mod_head = tr ? &tr->mod_trace : NULL;
4053 iter->mod_list = mod_head;
4055 if (file->f_mode & FMODE_WRITE) {
4056 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
4058 if (file->f_flags & O_TRUNC) {
4059 iter->hash = alloc_ftrace_hash(size_bits);
4060 clear_ftrace_mod_list(mod_head);
4062 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
4066 trace_parser_put(&iter->parser);
4074 if (file->f_mode & FMODE_READ) {
4075 iter->pg = ftrace_pages_start;
4077 ret = seq_open(file, &show_ftrace_seq_ops);
4079 struct seq_file *m = file->private_data;
4083 free_ftrace_hash(iter->hash);
4084 trace_parser_put(&iter->parser);
4087 file->private_data = iter;
4090 mutex_unlock(&ops->func_hash->regex_lock);
4096 trace_array_put(tr);
4103 ftrace_filter_open(struct inode *inode, struct file *file)
4105 struct ftrace_ops *ops = inode->i_private;
4107 /* Checks for tracefs lockdown */
4108 return ftrace_regex_open(ops,
4109 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
4114 ftrace_notrace_open(struct inode *inode, struct file *file)
4116 struct ftrace_ops *ops = inode->i_private;
4118 /* Checks for tracefs lockdown */
4119 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
4123 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
4124 struct ftrace_glob {
4131 * If symbols in an architecture don't correspond exactly to the user-visible
4132 * name of what they represent, it is possible to define this function to
4133 * perform the necessary adjustments.
4135 char * __weak arch_ftrace_match_adjust(char *str, const char *search)
4140 static int ftrace_match(char *str, struct ftrace_glob *g)
4145 str = arch_ftrace_match_adjust(str, g->search);
4149 if (strcmp(str, g->search) == 0)
4152 case MATCH_FRONT_ONLY:
4153 if (strncmp(str, g->search, g->len) == 0)
4156 case MATCH_MIDDLE_ONLY:
4157 if (strstr(str, g->search))
4160 case MATCH_END_ONLY:
4162 if (slen >= g->len &&
4163 memcmp(str + slen - g->len, g->search, g->len) == 0)
4167 if (glob_match(g->search, str))
4176 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
4178 struct ftrace_func_entry *entry;
4181 entry = ftrace_lookup_ip(hash, rec->ip);
4183 /* Do nothing if it doesn't exist */
4187 free_hash_entry(hash, entry);
4189 /* Do nothing if it exists */
4192 if (add_hash_entry(hash, rec->ip) == NULL)
4199 add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
4202 long index = simple_strtoul(func_g->search, NULL, 0);
4203 struct ftrace_page *pg;
4204 struct dyn_ftrace *rec;
4206 /* The index starts at 1 */
4210 do_for_each_ftrace_rec(pg, rec) {
4211 if (pg->index <= index) {
4213 /* this is a double loop, break goes to the next page */
4216 rec = &pg->records[index];
4217 enter_record(hash, rec, clear_filter);
4219 } while_for_each_ftrace_rec();
4223 #ifdef FTRACE_MCOUNT_MAX_OFFSET
4224 static int lookup_ip(unsigned long ip, char **modname, char *str)
4226 unsigned long offset;
4228 kallsyms_lookup(ip, NULL, &offset, modname, str);
4229 if (offset > FTRACE_MCOUNT_MAX_OFFSET)
4234 static int lookup_ip(unsigned long ip, char **modname, char *str)
4236 kallsyms_lookup(ip, NULL, NULL, modname, str);
4242 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
4243 struct ftrace_glob *mod_g, int exclude_mod)
4245 char str[KSYM_SYMBOL_LEN];
4248 if (lookup_ip(rec->ip, &modname, str)) {
4249 /* This should only happen when a rec is disabled */
4250 WARN_ON_ONCE(system_state == SYSTEM_RUNNING &&
4251 !(rec->flags & FTRACE_FL_DISABLED));
4256 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
4258 /* blank module name to match all modules */
4260 /* blank module globbing: modname xor exclude_mod */
4261 if (!exclude_mod != !modname)
4267 * exclude_mod is set to trace everything but the given
4268 * module. If it is set and the module matches, then
4269 * return 0. If it is not set, and the module doesn't match
4270 * also return 0. Otherwise, check the function to see if
4273 if (!mod_matches == !exclude_mod)
4276 /* blank search means to match all funcs in the mod */
4281 return ftrace_match(str, func_g);
4285 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
4287 struct ftrace_page *pg;
4288 struct dyn_ftrace *rec;
4289 struct ftrace_glob func_g = { .type = MATCH_FULL };
4290 struct ftrace_glob mod_g = { .type = MATCH_FULL };
4291 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
4292 int exclude_mod = 0;
4295 int clear_filter = 0;
4298 func_g.type = filter_parse_regex(func, len, &func_g.search,
4300 func_g.len = strlen(func_g.search);
4304 mod_g.type = filter_parse_regex(mod, strlen(mod),
4305 &mod_g.search, &exclude_mod);
4306 mod_g.len = strlen(mod_g.search);
4309 mutex_lock(&ftrace_lock);
4311 if (unlikely(ftrace_disabled))
4314 if (func_g.type == MATCH_INDEX) {
4315 found = add_rec_by_index(hash, &func_g, clear_filter);
4319 do_for_each_ftrace_rec(pg, rec) {
4321 if (rec->flags & FTRACE_FL_DISABLED)
4324 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
4325 ret = enter_record(hash, rec, clear_filter);
4333 } while_for_each_ftrace_rec();
4335 mutex_unlock(&ftrace_lock);
4341 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
4343 return match_records(hash, buff, len, NULL);
4346 static void ftrace_ops_update_code(struct ftrace_ops *ops,
4347 struct ftrace_ops_hash *old_hash)
4349 struct ftrace_ops *op;
4351 if (!ftrace_enabled)
4354 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4355 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4360 * If this is the shared global_ops filter, then we need to
4361 * check if there is another ops that shares it, is enabled.
4362 * If so, we still need to run the modify code.
4364 if (ops->func_hash != &global_ops.local_hash)
4367 do_for_each_ftrace_op(op, ftrace_ops_list) {
4368 if (op->func_hash == &global_ops.local_hash &&
4369 op->flags & FTRACE_OPS_FL_ENABLED) {
4370 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4371 /* Only need to do this once */
4374 } while_for_each_ftrace_op(op);
4377 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
4378 struct ftrace_hash **orig_hash,
4379 struct ftrace_hash *hash,
4382 struct ftrace_ops_hash old_hash_ops;
4383 struct ftrace_hash *old_hash;
4386 old_hash = *orig_hash;
4387 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4388 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4389 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4391 ftrace_ops_update_code(ops, &old_hash_ops);
4392 free_ftrace_hash_rcu(old_hash);
4397 static bool module_exists(const char *module)
4399 /* All modules have the symbol __this_module */
4400 static const char this_mod[] = "__this_module";
4401 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
4405 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
4407 if (n > sizeof(modname) - 1)
4410 val = module_kallsyms_lookup_name(modname);
4414 static int cache_mod(struct trace_array *tr,
4415 const char *func, char *module, int enable)
4417 struct ftrace_mod_load *ftrace_mod, *n;
4418 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4421 mutex_lock(&ftrace_lock);
4423 /* We do not cache inverse filters */
4424 if (func[0] == '!') {
4428 /* Look to remove this hash */
4429 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4430 if (strcmp(ftrace_mod->module, module) != 0)
4433 /* no func matches all */
4434 if (strcmp(func, "*") == 0 ||
4435 (ftrace_mod->func &&
4436 strcmp(ftrace_mod->func, func) == 0)) {
4438 free_ftrace_mod(ftrace_mod);
4446 /* We only care about modules that have not been loaded yet */
4447 if (module_exists(module))
4450 /* Save this string off, and execute it when the module is loaded */
4451 ret = ftrace_add_mod(tr, func, module, enable);
4453 mutex_unlock(&ftrace_lock);
4459 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4460 int reset, int enable);
4462 #ifdef CONFIG_MODULES
4463 static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4464 char *mod, bool enable)
4466 struct ftrace_mod_load *ftrace_mod, *n;
4467 struct ftrace_hash **orig_hash, *new_hash;
4468 LIST_HEAD(process_mods);
4471 mutex_lock(&ops->func_hash->regex_lock);
4474 orig_hash = &ops->func_hash->filter_hash;
4476 orig_hash = &ops->func_hash->notrace_hash;
4478 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4481 goto out; /* warn? */
4483 mutex_lock(&ftrace_lock);
4485 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4487 if (strcmp(ftrace_mod->module, mod) != 0)
4490 if (ftrace_mod->func)
4491 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4493 func = kstrdup("*", GFP_KERNEL);
4495 if (!func) /* warn? */
4498 list_move(&ftrace_mod->list, &process_mods);
4500 /* Use the newly allocated func, as it may be "*" */
4501 kfree(ftrace_mod->func);
4502 ftrace_mod->func = func;
4505 mutex_unlock(&ftrace_lock);
4507 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4509 func = ftrace_mod->func;
4511 /* Grabs ftrace_lock, which is why we have this extra step */
4512 match_records(new_hash, func, strlen(func), mod);
4513 free_ftrace_mod(ftrace_mod);
4516 if (enable && list_empty(head))
4517 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4519 mutex_lock(&ftrace_lock);
4521 ftrace_hash_move_and_update_ops(ops, orig_hash,
4523 mutex_unlock(&ftrace_lock);
4526 mutex_unlock(&ops->func_hash->regex_lock);
4528 free_ftrace_hash(new_hash);
4531 static void process_cached_mods(const char *mod_name)
4533 struct trace_array *tr;
4536 mod = kstrdup(mod_name, GFP_KERNEL);
4540 mutex_lock(&trace_types_lock);
4541 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4542 if (!list_empty(&tr->mod_trace))
4543 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4544 if (!list_empty(&tr->mod_notrace))
4545 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4547 mutex_unlock(&trace_types_lock);
4554 * We register the module command as a template to show others how
4555 * to register the a command as well.
4559 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4560 char *func_orig, char *cmd, char *module, int enable)
4565 /* match_records() modifies func, and we need the original */
4566 func = kstrdup(func_orig, GFP_KERNEL);
4571 * cmd == 'mod' because we only registered this func
4572 * for the 'mod' ftrace_func_command.
4573 * But if you register one func with multiple commands,
4574 * you can tell which command was used by the cmd
4577 ret = match_records(hash, func, strlen(func), module);
4581 return cache_mod(tr, func_orig, module, enable);
4587 static struct ftrace_func_command ftrace_mod_cmd = {
4589 .func = ftrace_mod_callback,
4592 static int __init ftrace_mod_cmd_init(void)
4594 return register_ftrace_command(&ftrace_mod_cmd);
4596 core_initcall(ftrace_mod_cmd_init);
4598 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4599 struct ftrace_ops *op, struct ftrace_regs *fregs)
4601 struct ftrace_probe_ops *probe_ops;
4602 struct ftrace_func_probe *probe;
4604 probe = container_of(op, struct ftrace_func_probe, ops);
4605 probe_ops = probe->probe_ops;
4608 * Disable preemption for these calls to prevent a RCU grace
4609 * period. This syncs the hash iteration and freeing of items
4610 * on the hash. rcu_read_lock is too dangerous here.
4612 preempt_disable_notrace();
4613 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4614 preempt_enable_notrace();
4617 struct ftrace_func_map {
4618 struct ftrace_func_entry entry;
4622 struct ftrace_func_mapper {
4623 struct ftrace_hash hash;
4627 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4629 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4631 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4633 struct ftrace_hash *hash;
4636 * The mapper is simply a ftrace_hash, but since the entries
4637 * in the hash are not ftrace_func_entry type, we define it
4638 * as a separate structure.
4640 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4641 return (struct ftrace_func_mapper *)hash;
4645 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4646 * @mapper: The mapper that has the ip maps
4647 * @ip: the instruction pointer to find the data for
4649 * Returns the data mapped to @ip if found otherwise NULL. The return
4650 * is actually the address of the mapper data pointer. The address is
4651 * returned for use cases where the data is no bigger than a long, and
4652 * the user can use the data pointer as its data instead of having to
4653 * allocate more memory for the reference.
4655 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4658 struct ftrace_func_entry *entry;
4659 struct ftrace_func_map *map;
4661 entry = ftrace_lookup_ip(&mapper->hash, ip);
4665 map = (struct ftrace_func_map *)entry;
4670 * ftrace_func_mapper_add_ip - Map some data to an ip
4671 * @mapper: The mapper that has the ip maps
4672 * @ip: The instruction pointer address to map @data to
4673 * @data: The data to map to @ip
4675 * Returns 0 on success otherwise an error.
4677 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4678 unsigned long ip, void *data)
4680 struct ftrace_func_entry *entry;
4681 struct ftrace_func_map *map;
4683 entry = ftrace_lookup_ip(&mapper->hash, ip);
4687 map = kmalloc(sizeof(*map), GFP_KERNEL);
4694 __add_hash_entry(&mapper->hash, &map->entry);
4700 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4701 * @mapper: The mapper that has the ip maps
4702 * @ip: The instruction pointer address to remove the data from
4704 * Returns the data if it is found, otherwise NULL.
4705 * Note, if the data pointer is used as the data itself, (see
4706 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4707 * if the data pointer was set to zero.
4709 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4712 struct ftrace_func_entry *entry;
4713 struct ftrace_func_map *map;
4716 entry = ftrace_lookup_ip(&mapper->hash, ip);
4720 map = (struct ftrace_func_map *)entry;
4723 remove_hash_entry(&mapper->hash, entry);
4730 * free_ftrace_func_mapper - free a mapping of ips and data
4731 * @mapper: The mapper that has the ip maps
4732 * @free_func: A function to be called on each data item.
4734 * This is used to free the function mapper. The @free_func is optional
4735 * and can be used if the data needs to be freed as well.
4737 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4738 ftrace_mapper_func free_func)
4740 struct ftrace_func_entry *entry;
4741 struct ftrace_func_map *map;
4742 struct hlist_head *hhd;
4748 if (free_func && mapper->hash.count) {
4749 size = 1 << mapper->hash.size_bits;
4750 for (i = 0; i < size; i++) {
4751 hhd = &mapper->hash.buckets[i];
4752 hlist_for_each_entry(entry, hhd, hlist) {
4753 map = (struct ftrace_func_map *)entry;
4758 free_ftrace_hash(&mapper->hash);
4761 static void release_probe(struct ftrace_func_probe *probe)
4763 struct ftrace_probe_ops *probe_ops;
4765 mutex_lock(&ftrace_lock);
4767 WARN_ON(probe->ref <= 0);
4769 /* Subtract the ref that was used to protect this instance */
4773 probe_ops = probe->probe_ops;
4775 * Sending zero as ip tells probe_ops to free
4776 * the probe->data itself
4778 if (probe_ops->free)
4779 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4780 list_del(&probe->list);
4783 mutex_unlock(&ftrace_lock);
4786 static void acquire_probe_locked(struct ftrace_func_probe *probe)
4789 * Add one ref to keep it from being freed when releasing the
4790 * ftrace_lock mutex.
4796 register_ftrace_function_probe(char *glob, struct trace_array *tr,
4797 struct ftrace_probe_ops *probe_ops,
4800 struct ftrace_func_probe *probe = NULL, *iter;
4801 struct ftrace_func_entry *entry;
4802 struct ftrace_hash **orig_hash;
4803 struct ftrace_hash *old_hash;
4804 struct ftrace_hash *hash;
4813 /* We do not support '!' for function probes */
4814 if (WARN_ON(glob[0] == '!'))
4818 mutex_lock(&ftrace_lock);
4819 /* Check if the probe_ops is already registered */
4820 list_for_each_entry(iter, &tr->func_probes, list) {
4821 if (iter->probe_ops == probe_ops) {
4827 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4829 mutex_unlock(&ftrace_lock);
4832 probe->probe_ops = probe_ops;
4833 probe->ops.func = function_trace_probe_call;
4835 ftrace_ops_init(&probe->ops);
4836 list_add(&probe->list, &tr->func_probes);
4839 acquire_probe_locked(probe);
4841 mutex_unlock(&ftrace_lock);
4844 * Note, there's a small window here that the func_hash->filter_hash
4845 * may be NULL or empty. Need to be careful when reading the loop.
4847 mutex_lock(&probe->ops.func_hash->regex_lock);
4849 orig_hash = &probe->ops.func_hash->filter_hash;
4850 old_hash = *orig_hash;
4851 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4858 ret = ftrace_match_records(hash, glob, strlen(glob));
4860 /* Nothing found? */
4867 size = 1 << hash->size_bits;
4868 for (i = 0; i < size; i++) {
4869 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4870 if (ftrace_lookup_ip(old_hash, entry->ip))
4873 * The caller might want to do something special
4874 * for each function we find. We call the callback
4875 * to give the caller an opportunity to do so.
4877 if (probe_ops->init) {
4878 ret = probe_ops->init(probe_ops, tr,
4882 if (probe_ops->free && count)
4883 probe_ops->free(probe_ops, tr,
4893 mutex_lock(&ftrace_lock);
4896 /* Nothing was added? */
4901 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4906 /* One ref for each new function traced */
4907 probe->ref += count;
4909 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4910 ret = ftrace_startup(&probe->ops, 0);
4913 mutex_unlock(&ftrace_lock);
4918 mutex_unlock(&probe->ops.func_hash->regex_lock);
4919 free_ftrace_hash(hash);
4921 release_probe(probe);
4926 if (!probe_ops->free || !count)
4929 /* Failed to do the move, need to call the free functions */
4930 for (i = 0; i < size; i++) {
4931 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4932 if (ftrace_lookup_ip(old_hash, entry->ip))
4934 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4941 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4942 struct ftrace_probe_ops *probe_ops)
4944 struct ftrace_func_probe *probe = NULL, *iter;
4945 struct ftrace_ops_hash old_hash_ops;
4946 struct ftrace_func_entry *entry;
4947 struct ftrace_glob func_g;
4948 struct ftrace_hash **orig_hash;
4949 struct ftrace_hash *old_hash;
4950 struct ftrace_hash *hash = NULL;
4951 struct hlist_node *tmp;
4952 struct hlist_head hhd;
4953 char str[KSYM_SYMBOL_LEN];
4955 int i, ret = -ENODEV;
4958 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4959 func_g.search = NULL;
4963 func_g.type = filter_parse_regex(glob, strlen(glob),
4964 &func_g.search, ¬);
4965 func_g.len = strlen(func_g.search);
4967 /* we do not support '!' for function probes */
4972 mutex_lock(&ftrace_lock);
4973 /* Check if the probe_ops is already registered */
4974 list_for_each_entry(iter, &tr->func_probes, list) {
4975 if (iter->probe_ops == probe_ops) {
4981 goto err_unlock_ftrace;
4984 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4985 goto err_unlock_ftrace;
4987 acquire_probe_locked(probe);
4989 mutex_unlock(&ftrace_lock);
4991 mutex_lock(&probe->ops.func_hash->regex_lock);
4993 orig_hash = &probe->ops.func_hash->filter_hash;
4994 old_hash = *orig_hash;
4996 if (ftrace_hash_empty(old_hash))
4999 old_hash_ops.filter_hash = old_hash;
5000 /* Probes only have filters */
5001 old_hash_ops.notrace_hash = NULL;
5004 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
5008 INIT_HLIST_HEAD(&hhd);
5010 size = 1 << hash->size_bits;
5011 for (i = 0; i < size; i++) {
5012 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
5014 if (func_g.search) {
5015 kallsyms_lookup(entry->ip, NULL, NULL,
5017 if (!ftrace_match(str, &func_g))
5021 remove_hash_entry(hash, entry);
5022 hlist_add_head(&entry->hlist, &hhd);
5026 /* Nothing found? */
5032 mutex_lock(&ftrace_lock);
5034 WARN_ON(probe->ref < count);
5036 probe->ref -= count;
5038 if (ftrace_hash_empty(hash))
5039 ftrace_shutdown(&probe->ops, 0);
5041 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
5044 /* still need to update the function call sites */
5045 if (ftrace_enabled && !ftrace_hash_empty(hash))
5046 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
5050 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
5051 hlist_del(&entry->hlist);
5052 if (probe_ops->free)
5053 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
5056 mutex_unlock(&ftrace_lock);
5059 mutex_unlock(&probe->ops.func_hash->regex_lock);
5060 free_ftrace_hash(hash);
5062 release_probe(probe);
5067 mutex_unlock(&ftrace_lock);
5071 void clear_ftrace_function_probes(struct trace_array *tr)
5073 struct ftrace_func_probe *probe, *n;
5075 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
5076 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
5079 static LIST_HEAD(ftrace_commands);
5080 static DEFINE_MUTEX(ftrace_cmd_mutex);
5083 * Currently we only register ftrace commands from __init, so mark this
5086 __init int register_ftrace_command(struct ftrace_func_command *cmd)
5088 struct ftrace_func_command *p;
5091 mutex_lock(&ftrace_cmd_mutex);
5092 list_for_each_entry(p, &ftrace_commands, list) {
5093 if (strcmp(cmd->name, p->name) == 0) {
5098 list_add(&cmd->list, &ftrace_commands);
5100 mutex_unlock(&ftrace_cmd_mutex);
5106 * Currently we only unregister ftrace commands from __init, so mark
5109 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
5111 struct ftrace_func_command *p, *n;
5114 mutex_lock(&ftrace_cmd_mutex);
5115 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
5116 if (strcmp(cmd->name, p->name) == 0) {
5118 list_del_init(&p->list);
5123 mutex_unlock(&ftrace_cmd_mutex);
5128 static int ftrace_process_regex(struct ftrace_iterator *iter,
5129 char *buff, int len, int enable)
5131 struct ftrace_hash *hash = iter->hash;
5132 struct trace_array *tr = iter->ops->private;
5133 char *func, *command, *next = buff;
5134 struct ftrace_func_command *p;
5137 func = strsep(&next, ":");
5140 ret = ftrace_match_records(hash, func, len);
5150 command = strsep(&next, ":");
5152 mutex_lock(&ftrace_cmd_mutex);
5153 list_for_each_entry(p, &ftrace_commands, list) {
5154 if (strcmp(p->name, command) == 0) {
5155 ret = p->func(tr, hash, func, command, next, enable);
5160 mutex_unlock(&ftrace_cmd_mutex);
5166 ftrace_regex_write(struct file *file, const char __user *ubuf,
5167 size_t cnt, loff_t *ppos, int enable)
5169 struct ftrace_iterator *iter;
5170 struct trace_parser *parser;
5176 if (file->f_mode & FMODE_READ) {
5177 struct seq_file *m = file->private_data;
5180 iter = file->private_data;
5182 if (unlikely(ftrace_disabled))
5185 /* iter->hash is a local copy, so we don't need regex_lock */
5187 parser = &iter->parser;
5188 read = trace_get_user(parser, ubuf, cnt, ppos);
5190 if (read >= 0 && trace_parser_loaded(parser) &&
5191 !trace_parser_cont(parser)) {
5192 ret = ftrace_process_regex(iter, parser->buffer,
5193 parser->idx, enable);
5194 trace_parser_clear(parser);
5205 ftrace_filter_write(struct file *file, const char __user *ubuf,
5206 size_t cnt, loff_t *ppos)
5208 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
5212 ftrace_notrace_write(struct file *file, const char __user *ubuf,
5213 size_t cnt, loff_t *ppos)
5215 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
5219 __ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
5221 struct ftrace_func_entry *entry;
5223 ip = ftrace_location(ip);
5228 entry = ftrace_lookup_ip(hash, ip);
5231 free_hash_entry(hash, entry);
5235 entry = add_hash_entry(hash, ip);
5236 return entry ? 0 : -ENOMEM;
5240 ftrace_match_addr(struct ftrace_hash *hash, unsigned long *ips,
5241 unsigned int cnt, int remove)
5246 for (i = 0; i < cnt; i++) {
5247 err = __ftrace_match_addr(hash, ips[i], remove);
5250 * This expects the @hash is a temporary hash and if this
5251 * fails the caller must free the @hash.
5260 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
5261 unsigned long *ips, unsigned int cnt,
5262 int remove, int reset, int enable)
5264 struct ftrace_hash **orig_hash;
5265 struct ftrace_hash *hash;
5268 if (unlikely(ftrace_disabled))
5271 mutex_lock(&ops->func_hash->regex_lock);
5274 orig_hash = &ops->func_hash->filter_hash;
5276 orig_hash = &ops->func_hash->notrace_hash;
5279 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5281 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
5285 goto out_regex_unlock;
5288 if (buf && !ftrace_match_records(hash, buf, len)) {
5290 goto out_regex_unlock;
5293 ret = ftrace_match_addr(hash, ips, cnt, remove);
5295 goto out_regex_unlock;
5298 mutex_lock(&ftrace_lock);
5299 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
5300 mutex_unlock(&ftrace_lock);
5303 mutex_unlock(&ops->func_hash->regex_lock);
5305 free_ftrace_hash(hash);
5310 ftrace_set_addr(struct ftrace_ops *ops, unsigned long *ips, unsigned int cnt,
5311 int remove, int reset, int enable)
5313 return ftrace_set_hash(ops, NULL, 0, ips, cnt, remove, reset, enable);
5316 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
5318 struct ftrace_direct_func {
5319 struct list_head next;
5324 static LIST_HEAD(ftrace_direct_funcs);
5326 static int register_ftrace_function_nolock(struct ftrace_ops *ops);
5329 * If there are multiple ftrace_ops, use SAVE_REGS by default, so that direct
5330 * call will be jumped from ftrace_regs_caller. Only if the architecture does
5331 * not support ftrace_regs_caller but direct_call, use SAVE_ARGS so that it
5332 * jumps from ftrace_caller for multiple ftrace_ops.
5334 #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_REGS
5335 #define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_ARGS)
5337 #define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS)
5340 static int check_direct_multi(struct ftrace_ops *ops)
5342 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5344 if ((ops->flags & MULTI_FLAGS) != MULTI_FLAGS)
5349 static void remove_direct_functions_hash(struct ftrace_hash *hash, unsigned long addr)
5351 struct ftrace_func_entry *entry, *del;
5354 size = 1 << hash->size_bits;
5355 for (i = 0; i < size; i++) {
5356 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5357 del = __ftrace_lookup_ip(direct_functions, entry->ip);
5358 if (del && del->direct == addr) {
5359 remove_hash_entry(direct_functions, del);
5367 * register_ftrace_direct - Call a custom trampoline directly
5368 * for multiple functions registered in @ops
5369 * @ops: The address of the struct ftrace_ops object
5370 * @addr: The address of the trampoline to call at @ops functions
5372 * This is used to connect a direct calls to @addr from the nop locations
5373 * of the functions registered in @ops (with by ftrace_set_filter_ip
5376 * The location that it calls (@addr) must be able to handle a direct call,
5377 * and save the parameters of the function being traced, and restore them
5378 * (or inject new ones if needed), before returning.
5382 * -EINVAL - The @ops object was already registered with this call or
5383 * when there are no functions in @ops object.
5384 * -EBUSY - Another direct function is already attached (there can be only one)
5385 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
5386 * -ENOMEM - There was an allocation failure.
5388 int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
5390 struct ftrace_hash *hash, *new_hash = NULL, *free_hash = NULL;
5391 struct ftrace_func_entry *entry, *new;
5392 int err = -EBUSY, size, i;
5394 if (ops->func || ops->trampoline)
5396 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5398 if (ops->flags & FTRACE_OPS_FL_ENABLED)
5401 hash = ops->func_hash->filter_hash;
5402 if (ftrace_hash_empty(hash))
5405 mutex_lock(&direct_mutex);
5407 /* Make sure requested entries are not already registered.. */
5408 size = 1 << hash->size_bits;
5409 for (i = 0; i < size; i++) {
5410 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5411 if (ftrace_find_rec_direct(entry->ip))
5418 /* Make a copy hash to place the new and the old entries in */
5419 size = hash->count + direct_functions->count;
5422 new_hash = alloc_ftrace_hash(fls(size));
5426 /* Now copy over the existing direct entries */
5427 size = 1 << direct_functions->size_bits;
5428 for (i = 0; i < size; i++) {
5429 hlist_for_each_entry(entry, &direct_functions->buckets[i], hlist) {
5430 new = add_hash_entry(new_hash, entry->ip);
5433 new->direct = entry->direct;
5437 /* ... and add the new entries */
5438 size = 1 << hash->size_bits;
5439 for (i = 0; i < size; i++) {
5440 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5441 new = add_hash_entry(new_hash, entry->ip);
5444 /* Update both the copy and the hash entry */
5446 entry->direct = addr;
5450 free_hash = direct_functions;
5451 rcu_assign_pointer(direct_functions, new_hash);
5454 ops->func = call_direct_funcs;
5455 ops->flags = MULTI_FLAGS;
5456 ops->trampoline = FTRACE_REGS_ADDR;
5457 ops->direct_call = addr;
5459 err = register_ftrace_function_nolock(ops);
5462 mutex_unlock(&direct_mutex);
5464 if (free_hash && free_hash != EMPTY_HASH) {
5465 synchronize_rcu_tasks();
5466 free_ftrace_hash(free_hash);
5470 free_ftrace_hash(new_hash);
5474 EXPORT_SYMBOL_GPL(register_ftrace_direct);
5477 * unregister_ftrace_direct - Remove calls to custom trampoline
5478 * previously registered by register_ftrace_direct for @ops object.
5479 * @ops: The address of the struct ftrace_ops object
5481 * This is used to remove a direct calls to @addr from the nop locations
5482 * of the functions registered in @ops (with by ftrace_set_filter_ip
5487 * -EINVAL - The @ops object was not properly registered.
5489 int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr,
5492 struct ftrace_hash *hash = ops->func_hash->filter_hash;
5495 if (check_direct_multi(ops))
5497 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5500 mutex_lock(&direct_mutex);
5501 err = unregister_ftrace_function(ops);
5502 remove_direct_functions_hash(hash, addr);
5503 mutex_unlock(&direct_mutex);
5505 /* cleanup for possible another register call */
5507 ops->trampoline = 0;
5510 ftrace_free_filter(ops);
5513 EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
5516 __modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
5518 struct ftrace_hash *hash;
5519 struct ftrace_func_entry *entry, *iter;
5520 static struct ftrace_ops tmp_ops = {
5521 .func = ftrace_stub,
5522 .flags = FTRACE_OPS_FL_STUB,
5527 lockdep_assert_held_once(&direct_mutex);
5529 /* Enable the tmp_ops to have the same functions as the direct ops */
5530 ftrace_ops_init(&tmp_ops);
5531 tmp_ops.func_hash = ops->func_hash;
5532 tmp_ops.direct_call = addr;
5534 err = register_ftrace_function_nolock(&tmp_ops);
5539 * Now the ftrace_ops_list_func() is called to do the direct callers.
5540 * We can safely change the direct functions attached to each entry.
5542 mutex_lock(&ftrace_lock);
5544 hash = ops->func_hash->filter_hash;
5545 size = 1 << hash->size_bits;
5546 for (i = 0; i < size; i++) {
5547 hlist_for_each_entry(iter, &hash->buckets[i], hlist) {
5548 entry = __ftrace_lookup_ip(direct_functions, iter->ip);
5551 entry->direct = addr;
5554 /* Prevent store tearing if a trampoline concurrently accesses the value */
5555 WRITE_ONCE(ops->direct_call, addr);
5557 mutex_unlock(&ftrace_lock);
5559 /* Removing the tmp_ops will add the updated direct callers to the functions */
5560 unregister_ftrace_function(&tmp_ops);
5566 * modify_ftrace_direct_nolock - Modify an existing direct 'multi' call
5567 * to call something else
5568 * @ops: The address of the struct ftrace_ops object
5569 * @addr: The address of the new trampoline to call at @ops functions
5571 * This is used to unregister currently registered direct caller and
5572 * register new one @addr on functions registered in @ops object.
5574 * Note there's window between ftrace_shutdown and ftrace_startup calls
5575 * where there will be no callbacks called.
5577 * Caller should already have direct_mutex locked, so we don't lock
5578 * direct_mutex here.
5580 * Returns: zero on success. Non zero on error, which includes:
5581 * -EINVAL - The @ops object was not properly registered.
5583 int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr)
5585 if (check_direct_multi(ops))
5587 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5590 return __modify_ftrace_direct(ops, addr);
5592 EXPORT_SYMBOL_GPL(modify_ftrace_direct_nolock);
5595 * modify_ftrace_direct - Modify an existing direct 'multi' call
5596 * to call something else
5597 * @ops: The address of the struct ftrace_ops object
5598 * @addr: The address of the new trampoline to call at @ops functions
5600 * This is used to unregister currently registered direct caller and
5601 * register new one @addr on functions registered in @ops object.
5603 * Note there's window between ftrace_shutdown and ftrace_startup calls
5604 * where there will be no callbacks called.
5606 * Returns: zero on success. Non zero on error, which includes:
5607 * -EINVAL - The @ops object was not properly registered.
5609 int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
5613 if (check_direct_multi(ops))
5615 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5618 mutex_lock(&direct_mutex);
5619 err = __modify_ftrace_direct(ops, addr);
5620 mutex_unlock(&direct_mutex);
5623 EXPORT_SYMBOL_GPL(modify_ftrace_direct);
5624 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
5627 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
5628 * @ops - the ops to set the filter with
5629 * @ip - the address to add to or remove from the filter.
5630 * @remove - non zero to remove the ip from the filter
5631 * @reset - non zero to reset all filters before applying this filter.
5633 * Filters denote which functions should be enabled when tracing is enabled
5634 * If @ip is NULL, it fails to update filter.
5636 * This can allocate memory which must be freed before @ops can be freed,
5637 * either by removing each filtered addr or by using
5638 * ftrace_free_filter(@ops).
5640 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
5641 int remove, int reset)
5643 ftrace_ops_init(ops);
5644 return ftrace_set_addr(ops, &ip, 1, remove, reset, 1);
5646 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
5649 * ftrace_set_filter_ips - set functions to filter on in ftrace by addresses
5650 * @ops - the ops to set the filter with
5651 * @ips - the array of addresses to add to or remove from the filter.
5652 * @cnt - the number of addresses in @ips
5653 * @remove - non zero to remove ips from the filter
5654 * @reset - non zero to reset all filters before applying this filter.
5656 * Filters denote which functions should be enabled when tracing is enabled
5657 * If @ips array or any ip specified within is NULL , it fails to update filter.
5659 * This can allocate memory which must be freed before @ops can be freed,
5660 * either by removing each filtered addr or by using
5661 * ftrace_free_filter(@ops).
5663 int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips,
5664 unsigned int cnt, int remove, int reset)
5666 ftrace_ops_init(ops);
5667 return ftrace_set_addr(ops, ips, cnt, remove, reset, 1);
5669 EXPORT_SYMBOL_GPL(ftrace_set_filter_ips);
5672 * ftrace_ops_set_global_filter - setup ops to use global filters
5673 * @ops - the ops which will use the global filters
5675 * ftrace users who need global function trace filtering should call this.
5676 * It can set the global filter only if ops were not initialized before.
5678 void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
5680 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
5683 ftrace_ops_init(ops);
5684 ops->func_hash = &global_ops.local_hash;
5686 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
5689 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
5690 int reset, int enable)
5692 return ftrace_set_hash(ops, buf, len, NULL, 0, 0, reset, enable);
5696 * ftrace_set_filter - set a function to filter on in ftrace
5697 * @ops - the ops to set the filter with
5698 * @buf - the string that holds the function filter text.
5699 * @len - the length of the string.
5700 * @reset - non zero to reset all filters before applying this filter.
5702 * Filters denote which functions should be enabled when tracing is enabled.
5703 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5705 * This can allocate memory which must be freed before @ops can be freed,
5706 * either by removing each filtered addr or by using
5707 * ftrace_free_filter(@ops).
5709 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
5712 ftrace_ops_init(ops);
5713 return ftrace_set_regex(ops, buf, len, reset, 1);
5715 EXPORT_SYMBOL_GPL(ftrace_set_filter);
5718 * ftrace_set_notrace - set a function to not trace in ftrace
5719 * @ops - the ops to set the notrace filter with
5720 * @buf - the string that holds the function notrace text.
5721 * @len - the length of the string.
5722 * @reset - non zero to reset all filters before applying this filter.
5724 * Notrace Filters denote which functions should not be enabled when tracing
5725 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5728 * This can allocate memory which must be freed before @ops can be freed,
5729 * either by removing each filtered addr or by using
5730 * ftrace_free_filter(@ops).
5732 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
5735 ftrace_ops_init(ops);
5736 return ftrace_set_regex(ops, buf, len, reset, 0);
5738 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
5740 * ftrace_set_global_filter - set a function to filter on with global tracers
5741 * @buf - the string that holds the function filter text.
5742 * @len - the length of the string.
5743 * @reset - non zero to reset all filters before applying this filter.
5745 * Filters denote which functions should be enabled when tracing is enabled.
5746 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5748 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
5750 ftrace_set_regex(&global_ops, buf, len, reset, 1);
5752 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
5755 * ftrace_set_global_notrace - set a function to not trace with global tracers
5756 * @buf - the string that holds the function notrace text.
5757 * @len - the length of the string.
5758 * @reset - non zero to reset all filters before applying this filter.
5760 * Notrace Filters denote which functions should not be enabled when tracing
5761 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5764 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
5766 ftrace_set_regex(&global_ops, buf, len, reset, 0);
5768 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
5771 * command line interface to allow users to set filters on boot up.
5773 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
5774 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5775 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
5777 /* Used by function selftest to not test if filter is set */
5778 bool ftrace_filter_param __initdata;
5780 static int __init set_ftrace_notrace(char *str)
5782 ftrace_filter_param = true;
5783 strscpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
5786 __setup("ftrace_notrace=", set_ftrace_notrace);
5788 static int __init set_ftrace_filter(char *str)
5790 ftrace_filter_param = true;
5791 strscpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
5794 __setup("ftrace_filter=", set_ftrace_filter);
5796 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5797 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
5798 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5799 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
5801 static int __init set_graph_function(char *str)
5803 strscpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
5806 __setup("ftrace_graph_filter=", set_graph_function);
5808 static int __init set_graph_notrace_function(char *str)
5810 strscpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
5813 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
5815 static int __init set_graph_max_depth_function(char *str)
5819 fgraph_max_depth = simple_strtoul(str, NULL, 0);
5822 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
5824 static void __init set_ftrace_early_graph(char *buf, int enable)
5828 struct ftrace_hash *hash;
5830 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5831 if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
5835 func = strsep(&buf, ",");
5836 /* we allow only one expression at a time */
5837 ret = ftrace_graph_set_hash(hash, func);
5839 printk(KERN_DEBUG "ftrace: function %s not "
5840 "traceable\n", func);
5844 ftrace_graph_hash = hash;
5846 ftrace_graph_notrace_hash = hash;
5848 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5851 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
5855 ftrace_ops_init(ops);
5858 func = strsep(&buf, ",");
5859 ftrace_set_regex(ops, func, strlen(func), 0, enable);
5863 static void __init set_ftrace_early_filters(void)
5865 if (ftrace_filter_buf[0])
5866 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
5867 if (ftrace_notrace_buf[0])
5868 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
5869 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5870 if (ftrace_graph_buf[0])
5871 set_ftrace_early_graph(ftrace_graph_buf, 1);
5872 if (ftrace_graph_notrace_buf[0])
5873 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
5874 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5877 int ftrace_regex_release(struct inode *inode, struct file *file)
5879 struct seq_file *m = (struct seq_file *)file->private_data;
5880 struct ftrace_iterator *iter;
5881 struct ftrace_hash **orig_hash;
5882 struct trace_parser *parser;
5885 if (file->f_mode & FMODE_READ) {
5887 seq_release(inode, file);
5889 iter = file->private_data;
5891 parser = &iter->parser;
5892 if (trace_parser_loaded(parser)) {
5893 int enable = !(iter->flags & FTRACE_ITER_NOTRACE);
5895 ftrace_process_regex(iter, parser->buffer,
5896 parser->idx, enable);
5899 trace_parser_put(parser);
5901 mutex_lock(&iter->ops->func_hash->regex_lock);
5903 if (file->f_mode & FMODE_WRITE) {
5904 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5907 orig_hash = &iter->ops->func_hash->filter_hash;
5909 if (list_empty(&iter->tr->mod_trace))
5910 iter->hash->flags &= ~FTRACE_HASH_FL_MOD;
5912 iter->hash->flags |= FTRACE_HASH_FL_MOD;
5915 orig_hash = &iter->ops->func_hash->notrace_hash;
5917 mutex_lock(&ftrace_lock);
5918 ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5919 iter->hash, filter_hash);
5920 mutex_unlock(&ftrace_lock);
5922 /* For read only, the hash is the ops hash */
5926 mutex_unlock(&iter->ops->func_hash->regex_lock);
5927 free_ftrace_hash(iter->hash);
5929 trace_array_put(iter->tr);
5935 static const struct file_operations ftrace_avail_fops = {
5936 .open = ftrace_avail_open,
5938 .llseek = seq_lseek,
5939 .release = seq_release_private,
5942 static const struct file_operations ftrace_enabled_fops = {
5943 .open = ftrace_enabled_open,
5945 .llseek = seq_lseek,
5946 .release = seq_release_private,
5949 static const struct file_operations ftrace_touched_fops = {
5950 .open = ftrace_touched_open,
5952 .llseek = seq_lseek,
5953 .release = seq_release_private,
5956 static const struct file_operations ftrace_avail_addrs_fops = {
5957 .open = ftrace_avail_addrs_open,
5959 .llseek = seq_lseek,
5960 .release = seq_release_private,
5963 static const struct file_operations ftrace_filter_fops = {
5964 .open = ftrace_filter_open,
5966 .write = ftrace_filter_write,
5967 .llseek = tracing_lseek,
5968 .release = ftrace_regex_release,
5971 static const struct file_operations ftrace_notrace_fops = {
5972 .open = ftrace_notrace_open,
5974 .write = ftrace_notrace_write,
5975 .llseek = tracing_lseek,
5976 .release = ftrace_regex_release,
5979 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5981 static DEFINE_MUTEX(graph_lock);
5983 struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
5984 struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
5986 enum graph_filter_type {
5987 GRAPH_FILTER_NOTRACE = 0,
5988 GRAPH_FILTER_FUNCTION,
5991 #define FTRACE_GRAPH_EMPTY ((void *)1)
5993 struct ftrace_graph_data {
5994 struct ftrace_hash *hash;
5995 struct ftrace_func_entry *entry;
5996 int idx; /* for hash table iteration */
5997 enum graph_filter_type type;
5998 struct ftrace_hash *new_hash;
5999 const struct seq_operations *seq_ops;
6000 struct trace_parser parser;
6004 __g_next(struct seq_file *m, loff_t *pos)
6006 struct ftrace_graph_data *fgd = m->private;
6007 struct ftrace_func_entry *entry = fgd->entry;
6008 struct hlist_head *head;
6009 int i, idx = fgd->idx;
6011 if (*pos >= fgd->hash->count)
6015 hlist_for_each_entry_continue(entry, hlist) {
6023 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
6024 head = &fgd->hash->buckets[i];
6025 hlist_for_each_entry(entry, head, hlist) {
6035 g_next(struct seq_file *m, void *v, loff_t *pos)
6038 return __g_next(m, pos);
6041 static void *g_start(struct seq_file *m, loff_t *pos)
6043 struct ftrace_graph_data *fgd = m->private;
6045 mutex_lock(&graph_lock);
6047 if (fgd->type == GRAPH_FILTER_FUNCTION)
6048 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6049 lockdep_is_held(&graph_lock));
6051 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6052 lockdep_is_held(&graph_lock));
6054 /* Nothing, tell g_show to print all functions are enabled */
6055 if (ftrace_hash_empty(fgd->hash) && !*pos)
6056 return FTRACE_GRAPH_EMPTY;
6060 return __g_next(m, pos);
6063 static void g_stop(struct seq_file *m, void *p)
6065 mutex_unlock(&graph_lock);
6068 static int g_show(struct seq_file *m, void *v)
6070 struct ftrace_func_entry *entry = v;
6075 if (entry == FTRACE_GRAPH_EMPTY) {
6076 struct ftrace_graph_data *fgd = m->private;
6078 if (fgd->type == GRAPH_FILTER_FUNCTION)
6079 seq_puts(m, "#### all functions enabled ####\n");
6081 seq_puts(m, "#### no functions disabled ####\n");
6085 seq_printf(m, "%ps\n", (void *)entry->ip);
6090 static const struct seq_operations ftrace_graph_seq_ops = {
6098 __ftrace_graph_open(struct inode *inode, struct file *file,
6099 struct ftrace_graph_data *fgd)
6102 struct ftrace_hash *new_hash = NULL;
6104 ret = security_locked_down(LOCKDOWN_TRACEFS);
6108 if (file->f_mode & FMODE_WRITE) {
6109 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
6111 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
6114 if (file->f_flags & O_TRUNC)
6115 new_hash = alloc_ftrace_hash(size_bits);
6117 new_hash = alloc_and_copy_ftrace_hash(size_bits,
6125 if (file->f_mode & FMODE_READ) {
6126 ret = seq_open(file, &ftrace_graph_seq_ops);
6128 struct seq_file *m = file->private_data;
6132 free_ftrace_hash(new_hash);
6136 file->private_data = fgd;
6139 if (ret < 0 && file->f_mode & FMODE_WRITE)
6140 trace_parser_put(&fgd->parser);
6142 fgd->new_hash = new_hash;
6145 * All uses of fgd->hash must be taken with the graph_lock
6146 * held. The graph_lock is going to be released, so force
6147 * fgd->hash to be reinitialized when it is taken again.
6155 ftrace_graph_open(struct inode *inode, struct file *file)
6157 struct ftrace_graph_data *fgd;
6160 if (unlikely(ftrace_disabled))
6163 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6167 mutex_lock(&graph_lock);
6169 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6170 lockdep_is_held(&graph_lock));
6171 fgd->type = GRAPH_FILTER_FUNCTION;
6172 fgd->seq_ops = &ftrace_graph_seq_ops;
6174 ret = __ftrace_graph_open(inode, file, fgd);
6178 mutex_unlock(&graph_lock);
6183 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
6185 struct ftrace_graph_data *fgd;
6188 if (unlikely(ftrace_disabled))
6191 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6195 mutex_lock(&graph_lock);
6197 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6198 lockdep_is_held(&graph_lock));
6199 fgd->type = GRAPH_FILTER_NOTRACE;
6200 fgd->seq_ops = &ftrace_graph_seq_ops;
6202 ret = __ftrace_graph_open(inode, file, fgd);
6206 mutex_unlock(&graph_lock);
6211 ftrace_graph_release(struct inode *inode, struct file *file)
6213 struct ftrace_graph_data *fgd;
6214 struct ftrace_hash *old_hash, *new_hash;
6215 struct trace_parser *parser;
6218 if (file->f_mode & FMODE_READ) {
6219 struct seq_file *m = file->private_data;
6222 seq_release(inode, file);
6224 fgd = file->private_data;
6228 if (file->f_mode & FMODE_WRITE) {
6230 parser = &fgd->parser;
6232 if (trace_parser_loaded((parser))) {
6233 ret = ftrace_graph_set_hash(fgd->new_hash,
6237 trace_parser_put(parser);
6239 new_hash = __ftrace_hash_move(fgd->new_hash);
6245 mutex_lock(&graph_lock);
6247 if (fgd->type == GRAPH_FILTER_FUNCTION) {
6248 old_hash = rcu_dereference_protected(ftrace_graph_hash,
6249 lockdep_is_held(&graph_lock));
6250 rcu_assign_pointer(ftrace_graph_hash, new_hash);
6252 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6253 lockdep_is_held(&graph_lock));
6254 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
6257 mutex_unlock(&graph_lock);
6260 * We need to do a hard force of sched synchronization.
6261 * This is because we use preempt_disable() to do RCU, but
6262 * the function tracers can be called where RCU is not watching
6263 * (like before user_exit()). We can not rely on the RCU
6264 * infrastructure to do the synchronization, thus we must do it
6267 if (old_hash != EMPTY_HASH)
6268 synchronize_rcu_tasks_rude();
6270 free_ftrace_hash(old_hash);
6274 free_ftrace_hash(fgd->new_hash);
6281 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
6283 struct ftrace_glob func_g;
6284 struct dyn_ftrace *rec;
6285 struct ftrace_page *pg;
6286 struct ftrace_func_entry *entry;
6291 func_g.type = filter_parse_regex(buffer, strlen(buffer),
6292 &func_g.search, ¬);
6294 func_g.len = strlen(func_g.search);
6296 mutex_lock(&ftrace_lock);
6298 if (unlikely(ftrace_disabled)) {
6299 mutex_unlock(&ftrace_lock);
6303 do_for_each_ftrace_rec(pg, rec) {
6305 if (rec->flags & FTRACE_FL_DISABLED)
6308 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
6309 entry = ftrace_lookup_ip(hash, rec->ip);
6316 if (add_hash_entry(hash, rec->ip) == NULL)
6320 free_hash_entry(hash, entry);
6325 } while_for_each_ftrace_rec();
6327 mutex_unlock(&ftrace_lock);
6336 ftrace_graph_write(struct file *file, const char __user *ubuf,
6337 size_t cnt, loff_t *ppos)
6339 ssize_t read, ret = 0;
6340 struct ftrace_graph_data *fgd = file->private_data;
6341 struct trace_parser *parser;
6346 /* Read mode uses seq functions */
6347 if (file->f_mode & FMODE_READ) {
6348 struct seq_file *m = file->private_data;
6352 parser = &fgd->parser;
6354 read = trace_get_user(parser, ubuf, cnt, ppos);
6356 if (read >= 0 && trace_parser_loaded(parser) &&
6357 !trace_parser_cont(parser)) {
6359 ret = ftrace_graph_set_hash(fgd->new_hash,
6361 trace_parser_clear(parser);
6370 static const struct file_operations ftrace_graph_fops = {
6371 .open = ftrace_graph_open,
6373 .write = ftrace_graph_write,
6374 .llseek = tracing_lseek,
6375 .release = ftrace_graph_release,
6378 static const struct file_operations ftrace_graph_notrace_fops = {
6379 .open = ftrace_graph_notrace_open,
6381 .write = ftrace_graph_write,
6382 .llseek = tracing_lseek,
6383 .release = ftrace_graph_release,
6385 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6387 void ftrace_create_filter_files(struct ftrace_ops *ops,
6388 struct dentry *parent)
6391 trace_create_file("set_ftrace_filter", TRACE_MODE_WRITE, parent,
6392 ops, &ftrace_filter_fops);
6394 trace_create_file("set_ftrace_notrace", TRACE_MODE_WRITE, parent,
6395 ops, &ftrace_notrace_fops);
6399 * The name "destroy_filter_files" is really a misnomer. Although
6400 * in the future, it may actually delete the files, but this is
6401 * really intended to make sure the ops passed in are disabled
6402 * and that when this function returns, the caller is free to
6405 * The "destroy" name is only to match the "create" name that this
6406 * should be paired with.
6408 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
6410 mutex_lock(&ftrace_lock);
6411 if (ops->flags & FTRACE_OPS_FL_ENABLED)
6412 ftrace_shutdown(ops, 0);
6413 ops->flags |= FTRACE_OPS_FL_DELETED;
6414 ftrace_free_filter(ops);
6415 mutex_unlock(&ftrace_lock);
6418 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
6421 trace_create_file("available_filter_functions", TRACE_MODE_READ,
6422 d_tracer, NULL, &ftrace_avail_fops);
6424 trace_create_file("available_filter_functions_addrs", TRACE_MODE_READ,
6425 d_tracer, NULL, &ftrace_avail_addrs_fops);
6427 trace_create_file("enabled_functions", TRACE_MODE_READ,
6428 d_tracer, NULL, &ftrace_enabled_fops);
6430 trace_create_file("touched_functions", TRACE_MODE_READ,
6431 d_tracer, NULL, &ftrace_touched_fops);
6433 ftrace_create_filter_files(&global_ops, d_tracer);
6435 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
6436 trace_create_file("set_graph_function", TRACE_MODE_WRITE, d_tracer,
6438 &ftrace_graph_fops);
6439 trace_create_file("set_graph_notrace", TRACE_MODE_WRITE, d_tracer,
6441 &ftrace_graph_notrace_fops);
6442 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6447 static int ftrace_cmp_ips(const void *a, const void *b)
6449 const unsigned long *ipa = a;
6450 const unsigned long *ipb = b;
6459 #ifdef CONFIG_FTRACE_SORT_STARTUP_TEST
6460 static void test_is_sorted(unsigned long *start, unsigned long count)
6464 for (i = 1; i < count; i++) {
6465 if (WARN(start[i - 1] > start[i],
6466 "[%d] %pS at %lx is not sorted with %pS at %lx\n", i,
6467 (void *)start[i - 1], start[i - 1],
6468 (void *)start[i], start[i]))
6472 pr_info("ftrace section at %px sorted properly\n", start);
6475 static void test_is_sorted(unsigned long *start, unsigned long count)
6480 static int ftrace_process_locs(struct module *mod,
6481 unsigned long *start,
6484 struct ftrace_page *pg_unuse = NULL;
6485 struct ftrace_page *start_pg;
6486 struct ftrace_page *pg;
6487 struct dyn_ftrace *rec;
6488 unsigned long skipped = 0;
6489 unsigned long count;
6492 unsigned long flags = 0; /* Shut up gcc */
6495 count = end - start;
6501 * Sorting mcount in vmlinux at build time depend on
6502 * CONFIG_BUILDTIME_MCOUNT_SORT, while mcount loc in
6503 * modules can not be sorted at build time.
6505 if (!IS_ENABLED(CONFIG_BUILDTIME_MCOUNT_SORT) || mod) {
6506 sort(start, count, sizeof(*start),
6507 ftrace_cmp_ips, NULL);
6509 test_is_sorted(start, count);
6512 start_pg = ftrace_allocate_pages(count);
6516 mutex_lock(&ftrace_lock);
6519 * Core and each module needs their own pages, as
6520 * modules will free them when they are removed.
6521 * Force a new page to be allocated for modules.
6524 WARN_ON(ftrace_pages || ftrace_pages_start);
6525 /* First initialization */
6526 ftrace_pages = ftrace_pages_start = start_pg;
6531 if (WARN_ON(ftrace_pages->next)) {
6532 /* Hmm, we have free pages? */
6533 while (ftrace_pages->next)
6534 ftrace_pages = ftrace_pages->next;
6537 ftrace_pages->next = start_pg;
6543 unsigned long end_offset;
6544 addr = ftrace_call_adjust(*p++);
6546 * Some architecture linkers will pad between
6547 * the different mcount_loc sections of different
6548 * object files to satisfy alignments.
6549 * Skip any NULL pointers.
6556 end_offset = (pg->index+1) * sizeof(pg->records[0]);
6557 if (end_offset > PAGE_SIZE << pg->order) {
6558 /* We should have allocated enough */
6559 if (WARN_ON(!pg->next))
6564 rec = &pg->records[pg->index++];
6569 pg_unuse = pg->next;
6573 /* Assign the last page to ftrace_pages */
6577 * We only need to disable interrupts on start up
6578 * because we are modifying code that an interrupt
6579 * may execute, and the modification is not atomic.
6580 * But for modules, nothing runs the code we modify
6581 * until we are finished with it, and there's no
6582 * reason to cause large interrupt latencies while we do it.
6585 local_irq_save(flags);
6586 ftrace_update_code(mod, start_pg);
6588 local_irq_restore(flags);
6591 mutex_unlock(&ftrace_lock);
6593 /* We should have used all pages unless we skipped some */
6596 ftrace_free_pages(pg_unuse);
6601 struct ftrace_mod_func {
6602 struct list_head list;
6608 struct ftrace_mod_map {
6609 struct rcu_head rcu;
6610 struct list_head list;
6612 unsigned long start_addr;
6613 unsigned long end_addr;
6614 struct list_head funcs;
6615 unsigned int num_funcs;
6618 static int ftrace_get_trampoline_kallsym(unsigned int symnum,
6619 unsigned long *value, char *type,
6620 char *name, char *module_name,
6623 struct ftrace_ops *op;
6625 list_for_each_entry_rcu(op, &ftrace_ops_trampoline_list, list) {
6626 if (!op->trampoline || symnum--)
6628 *value = op->trampoline;
6630 strscpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
6631 strscpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
6639 #if defined(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS) || defined(CONFIG_MODULES)
6641 * Check if the current ops references the given ip.
6643 * If the ops traces all functions, then it was already accounted for.
6644 * If the ops does not trace the current record function, skip it.
6645 * If the ops ignores the function via notrace filter, skip it.
6648 ops_references_ip(struct ftrace_ops *ops, unsigned long ip)
6650 /* If ops isn't enabled, ignore it */
6651 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
6654 /* If ops traces all then it includes this function */
6655 if (ops_traces_mod(ops))
6658 /* The function must be in the filter */
6659 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
6660 !__ftrace_lookup_ip(ops->func_hash->filter_hash, ip))
6663 /* If in notrace hash, we ignore it too */
6664 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, ip))
6671 #ifdef CONFIG_MODULES
6673 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
6675 static LIST_HEAD(ftrace_mod_maps);
6677 static int referenced_filters(struct dyn_ftrace *rec)
6679 struct ftrace_ops *ops;
6682 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
6683 if (ops_references_ip(ops, rec->ip)) {
6684 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_DIRECT))
6686 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_IPMODIFY))
6689 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
6690 rec->flags |= FTRACE_FL_REGS;
6691 if (cnt == 1 && ops->trampoline)
6692 rec->flags |= FTRACE_FL_TRAMP;
6694 rec->flags &= ~FTRACE_FL_TRAMP;
6702 clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
6704 struct ftrace_func_entry *entry;
6705 struct dyn_ftrace *rec;
6708 if (ftrace_hash_empty(hash))
6711 for (i = 0; i < pg->index; i++) {
6712 rec = &pg->records[i];
6713 entry = __ftrace_lookup_ip(hash, rec->ip);
6715 * Do not allow this rec to match again.
6716 * Yeah, it may waste some memory, but will be removed
6717 * if/when the hash is modified again.
6724 /* Clear any records from hashes */
6725 static void clear_mod_from_hashes(struct ftrace_page *pg)
6727 struct trace_array *tr;
6729 mutex_lock(&trace_types_lock);
6730 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6731 if (!tr->ops || !tr->ops->func_hash)
6733 mutex_lock(&tr->ops->func_hash->regex_lock);
6734 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
6735 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
6736 mutex_unlock(&tr->ops->func_hash->regex_lock);
6738 mutex_unlock(&trace_types_lock);
6741 static void ftrace_free_mod_map(struct rcu_head *rcu)
6743 struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
6744 struct ftrace_mod_func *mod_func;
6745 struct ftrace_mod_func *n;
6747 /* All the contents of mod_map are now not visible to readers */
6748 list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
6749 kfree(mod_func->name);
6750 list_del(&mod_func->list);
6757 void ftrace_release_mod(struct module *mod)
6759 struct ftrace_mod_map *mod_map;
6760 struct ftrace_mod_map *n;
6761 struct dyn_ftrace *rec;
6762 struct ftrace_page **last_pg;
6763 struct ftrace_page *tmp_page = NULL;
6764 struct ftrace_page *pg;
6766 mutex_lock(&ftrace_lock);
6768 if (ftrace_disabled)
6771 list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
6772 if (mod_map->mod == mod) {
6773 list_del_rcu(&mod_map->list);
6774 call_rcu(&mod_map->rcu, ftrace_free_mod_map);
6780 * Each module has its own ftrace_pages, remove
6781 * them from the list.
6783 last_pg = &ftrace_pages_start;
6784 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
6785 rec = &pg->records[0];
6786 if (within_module(rec->ip, mod)) {
6788 * As core pages are first, the first
6789 * page should never be a module page.
6791 if (WARN_ON(pg == ftrace_pages_start))
6794 /* Check if we are deleting the last page */
6795 if (pg == ftrace_pages)
6796 ftrace_pages = next_to_ftrace_page(last_pg);
6798 ftrace_update_tot_cnt -= pg->index;
6799 *last_pg = pg->next;
6801 pg->next = tmp_page;
6804 last_pg = &pg->next;
6807 mutex_unlock(&ftrace_lock);
6809 for (pg = tmp_page; pg; pg = tmp_page) {
6811 /* Needs to be called outside of ftrace_lock */
6812 clear_mod_from_hashes(pg);
6815 free_pages((unsigned long)pg->records, pg->order);
6816 ftrace_number_of_pages -= 1 << pg->order;
6818 tmp_page = pg->next;
6820 ftrace_number_of_groups--;
6824 void ftrace_module_enable(struct module *mod)
6826 struct dyn_ftrace *rec;
6827 struct ftrace_page *pg;
6829 mutex_lock(&ftrace_lock);
6831 if (ftrace_disabled)
6835 * If the tracing is enabled, go ahead and enable the record.
6837 * The reason not to enable the record immediately is the
6838 * inherent check of ftrace_make_nop/ftrace_make_call for
6839 * correct previous instructions. Making first the NOP
6840 * conversion puts the module to the correct state, thus
6841 * passing the ftrace_make_call check.
6843 * We also delay this to after the module code already set the
6844 * text to read-only, as we now need to set it back to read-write
6845 * so that we can modify the text.
6847 if (ftrace_start_up)
6848 ftrace_arch_code_modify_prepare();
6850 do_for_each_ftrace_rec(pg, rec) {
6853 * do_for_each_ftrace_rec() is a double loop.
6854 * module text shares the pg. If a record is
6855 * not part of this module, then skip this pg,
6856 * which the "break" will do.
6858 if (!within_module(rec->ip, mod))
6861 /* Weak functions should still be ignored */
6862 if (!test_for_valid_rec(rec)) {
6863 /* Clear all other flags. Should not be enabled anyway */
6864 rec->flags = FTRACE_FL_DISABLED;
6871 * When adding a module, we need to check if tracers are
6872 * currently enabled and if they are, and can trace this record,
6873 * we need to enable the module functions as well as update the
6874 * reference counts for those function records.
6876 if (ftrace_start_up)
6877 cnt += referenced_filters(rec);
6879 rec->flags &= ~FTRACE_FL_DISABLED;
6882 if (ftrace_start_up && cnt) {
6883 int failed = __ftrace_replace_code(rec, 1);
6885 ftrace_bug(failed, rec);
6890 } while_for_each_ftrace_rec();
6893 if (ftrace_start_up)
6894 ftrace_arch_code_modify_post_process();
6897 mutex_unlock(&ftrace_lock);
6899 process_cached_mods(mod->name);
6902 void ftrace_module_init(struct module *mod)
6906 if (ftrace_disabled || !mod->num_ftrace_callsites)
6909 ret = ftrace_process_locs(mod, mod->ftrace_callsites,
6910 mod->ftrace_callsites + mod->num_ftrace_callsites);
6912 pr_warn("ftrace: failed to allocate entries for module '%s' functions\n",
6916 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6917 struct dyn_ftrace *rec)
6919 struct ftrace_mod_func *mod_func;
6920 unsigned long symsize;
6921 unsigned long offset;
6922 char str[KSYM_SYMBOL_LEN];
6926 ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
6930 mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
6934 mod_func->name = kstrdup(str, GFP_KERNEL);
6935 if (!mod_func->name) {
6940 mod_func->ip = rec->ip - offset;
6941 mod_func->size = symsize;
6943 mod_map->num_funcs++;
6945 list_add_rcu(&mod_func->list, &mod_map->funcs);
6948 static struct ftrace_mod_map *
6949 allocate_ftrace_mod_map(struct module *mod,
6950 unsigned long start, unsigned long end)
6952 struct ftrace_mod_map *mod_map;
6954 mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
6959 mod_map->start_addr = start;
6960 mod_map->end_addr = end;
6961 mod_map->num_funcs = 0;
6963 INIT_LIST_HEAD_RCU(&mod_map->funcs);
6965 list_add_rcu(&mod_map->list, &ftrace_mod_maps);
6971 ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
6972 unsigned long addr, unsigned long *size,
6973 unsigned long *off, char *sym)
6975 struct ftrace_mod_func *found_func = NULL;
6976 struct ftrace_mod_func *mod_func;
6978 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6979 if (addr >= mod_func->ip &&
6980 addr < mod_func->ip + mod_func->size) {
6981 found_func = mod_func;
6988 *size = found_func->size;
6990 *off = addr - found_func->ip;
6992 strscpy(sym, found_func->name, KSYM_NAME_LEN);
6994 return found_func->name;
7001 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
7002 unsigned long *off, char **modname, char *sym)
7004 struct ftrace_mod_map *mod_map;
7005 const char *ret = NULL;
7007 /* mod_map is freed via call_rcu() */
7009 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
7010 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
7013 *modname = mod_map->mod->name;
7022 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7023 char *type, char *name,
7024 char *module_name, int *exported)
7026 struct ftrace_mod_map *mod_map;
7027 struct ftrace_mod_func *mod_func;
7031 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
7033 if (symnum >= mod_map->num_funcs) {
7034 symnum -= mod_map->num_funcs;
7038 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
7044 *value = mod_func->ip;
7046 strscpy(name, mod_func->name, KSYM_NAME_LEN);
7047 strscpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
7055 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7056 module_name, exported);
7062 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
7063 struct dyn_ftrace *rec) { }
7064 static inline struct ftrace_mod_map *
7065 allocate_ftrace_mod_map(struct module *mod,
7066 unsigned long start, unsigned long end)
7070 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7071 char *type, char *name, char *module_name,
7077 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7078 module_name, exported);
7082 #endif /* CONFIG_MODULES */
7084 struct ftrace_init_func {
7085 struct list_head list;
7089 /* Clear any init ips from hashes */
7091 clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
7093 struct ftrace_func_entry *entry;
7095 entry = ftrace_lookup_ip(hash, func->ip);
7097 * Do not allow this rec to match again.
7098 * Yeah, it may waste some memory, but will be removed
7099 * if/when the hash is modified again.
7106 clear_func_from_hashes(struct ftrace_init_func *func)
7108 struct trace_array *tr;
7110 mutex_lock(&trace_types_lock);
7111 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
7112 if (!tr->ops || !tr->ops->func_hash)
7114 mutex_lock(&tr->ops->func_hash->regex_lock);
7115 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
7116 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
7117 mutex_unlock(&tr->ops->func_hash->regex_lock);
7119 mutex_unlock(&trace_types_lock);
7122 static void add_to_clear_hash_list(struct list_head *clear_list,
7123 struct dyn_ftrace *rec)
7125 struct ftrace_init_func *func;
7127 func = kmalloc(sizeof(*func), GFP_KERNEL);
7129 MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
7134 list_add(&func->list, clear_list);
7137 void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
7139 unsigned long start = (unsigned long)(start_ptr);
7140 unsigned long end = (unsigned long)(end_ptr);
7141 struct ftrace_page **last_pg = &ftrace_pages_start;
7142 struct ftrace_page *pg;
7143 struct dyn_ftrace *rec;
7144 struct dyn_ftrace key;
7145 struct ftrace_mod_map *mod_map = NULL;
7146 struct ftrace_init_func *func, *func_next;
7147 LIST_HEAD(clear_hash);
7150 key.flags = end; /* overload flags, as it is unsigned long */
7152 mutex_lock(&ftrace_lock);
7155 * If we are freeing module init memory, then check if
7156 * any tracer is active. If so, we need to save a mapping of
7157 * the module functions being freed with the address.
7159 if (mod && ftrace_ops_list != &ftrace_list_end)
7160 mod_map = allocate_ftrace_mod_map(mod, start, end);
7162 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
7163 if (end < pg->records[0].ip ||
7164 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
7167 rec = bsearch(&key, pg->records, pg->index,
7168 sizeof(struct dyn_ftrace),
7173 /* rec will be cleared from hashes after ftrace_lock unlock */
7174 add_to_clear_hash_list(&clear_hash, rec);
7177 save_ftrace_mod_rec(mod_map, rec);
7180 ftrace_update_tot_cnt--;
7182 *last_pg = pg->next;
7184 free_pages((unsigned long)pg->records, pg->order);
7185 ftrace_number_of_pages -= 1 << pg->order;
7187 ftrace_number_of_groups--;
7189 pg = container_of(last_pg, struct ftrace_page, next);
7194 memmove(rec, rec + 1,
7195 (pg->index - (rec - pg->records)) * sizeof(*rec));
7196 /* More than one function may be in this block */
7199 mutex_unlock(&ftrace_lock);
7201 list_for_each_entry_safe(func, func_next, &clear_hash, list) {
7202 clear_func_from_hashes(func);
7207 void __init ftrace_free_init_mem(void)
7209 void *start = (void *)(&__init_begin);
7210 void *end = (void *)(&__init_end);
7212 ftrace_boot_snapshot();
7214 ftrace_free_mem(NULL, start, end);
7217 int __init __weak ftrace_dyn_arch_init(void)
7222 void __init ftrace_init(void)
7224 extern unsigned long __start_mcount_loc[];
7225 extern unsigned long __stop_mcount_loc[];
7226 unsigned long count, flags;
7229 local_irq_save(flags);
7230 ret = ftrace_dyn_arch_init();
7231 local_irq_restore(flags);
7235 count = __stop_mcount_loc - __start_mcount_loc;
7237 pr_info("ftrace: No functions to be traced?\n");
7241 pr_info("ftrace: allocating %ld entries in %ld pages\n",
7242 count, DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
7244 ret = ftrace_process_locs(NULL,
7248 pr_warn("ftrace: failed to allocate entries for functions\n");
7252 pr_info("ftrace: allocated %ld pages with %ld groups\n",
7253 ftrace_number_of_pages, ftrace_number_of_groups);
7255 last_ftrace_enabled = ftrace_enabled = 1;
7257 set_ftrace_early_filters();
7261 ftrace_disabled = 1;
7264 /* Do nothing if arch does not support this */
7265 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
7269 static void ftrace_update_trampoline(struct ftrace_ops *ops)
7271 unsigned long trampoline = ops->trampoline;
7273 arch_ftrace_update_trampoline(ops);
7274 if (ops->trampoline && ops->trampoline != trampoline &&
7275 (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) {
7276 /* Add to kallsyms before the perf events */
7277 ftrace_add_trampoline_to_kallsyms(ops);
7278 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
7279 ops->trampoline, ops->trampoline_size, false,
7280 FTRACE_TRAMPOLINE_SYM);
7282 * Record the perf text poke event after the ksymbol register
7285 perf_event_text_poke((void *)ops->trampoline, NULL, 0,
7286 (void *)ops->trampoline,
7287 ops->trampoline_size);
7291 void ftrace_init_trace_array(struct trace_array *tr)
7293 INIT_LIST_HEAD(&tr->func_probes);
7294 INIT_LIST_HEAD(&tr->mod_trace);
7295 INIT_LIST_HEAD(&tr->mod_notrace);
7299 struct ftrace_ops global_ops = {
7300 .func = ftrace_stub,
7301 .flags = FTRACE_OPS_FL_INITIALIZED |
7305 static int __init ftrace_nodyn_init(void)
7310 core_initcall(ftrace_nodyn_init);
7312 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
7313 static inline void ftrace_startup_all(int command) { }
7315 static void ftrace_update_trampoline(struct ftrace_ops *ops)
7319 #endif /* CONFIG_DYNAMIC_FTRACE */
7321 __init void ftrace_init_global_array_ops(struct trace_array *tr)
7323 tr->ops = &global_ops;
7324 tr->ops->private = tr;
7325 ftrace_init_trace_array(tr);
7328 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
7330 /* If we filter on pids, update to use the pid function */
7331 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
7332 if (WARN_ON(tr->ops->func != ftrace_stub))
7333 printk("ftrace ops had %pS for function\n",
7336 tr->ops->func = func;
7337 tr->ops->private = tr;
7340 void ftrace_reset_array_ops(struct trace_array *tr)
7342 tr->ops->func = ftrace_stub;
7345 static nokprobe_inline void
7346 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7347 struct ftrace_ops *ignored, struct ftrace_regs *fregs)
7349 struct pt_regs *regs = ftrace_get_regs(fregs);
7350 struct ftrace_ops *op;
7354 * The ftrace_test_and_set_recursion() will disable preemption,
7355 * which is required since some of the ops may be dynamically
7356 * allocated, they must be freed after a synchronize_rcu().
7358 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7362 do_for_each_ftrace_op(op, ftrace_ops_list) {
7363 /* Stub functions don't need to be called nor tested */
7364 if (op->flags & FTRACE_OPS_FL_STUB)
7367 * Check the following for each ops before calling their func:
7368 * if RCU flag is set, then rcu_is_watching() must be true
7369 * Otherwise test if the ip matches the ops filter
7371 * If any of the above fails then the op->func() is not executed.
7373 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
7374 ftrace_ops_test(op, ip, regs)) {
7375 if (FTRACE_WARN_ON(!op->func)) {
7376 pr_warn("op=%p %pS\n", op, op);
7379 op->func(ip, parent_ip, op, fregs);
7381 } while_for_each_ftrace_op(op);
7383 trace_clear_recursion(bit);
7387 * Some archs only support passing ip and parent_ip. Even though
7388 * the list function ignores the op parameter, we do not want any
7389 * C side effects, where a function is called without the caller
7390 * sending a third parameter.
7391 * Archs are to support both the regs and ftrace_ops at the same time.
7392 * If they support ftrace_ops, it is assumed they support regs.
7393 * If call backs want to use regs, they must either check for regs
7394 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
7395 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
7396 * An architecture can pass partial regs with ftrace_ops and still
7397 * set the ARCH_SUPPORTS_FTRACE_OPS.
7399 * In vmlinux.lds.h, ftrace_ops_list_func() is defined to be
7400 * arch_ftrace_ops_list_func.
7402 #if ARCH_SUPPORTS_FTRACE_OPS
7403 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7404 struct ftrace_ops *op, struct ftrace_regs *fregs)
7406 __ftrace_ops_list_func(ip, parent_ip, NULL, fregs);
7409 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
7411 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
7414 NOKPROBE_SYMBOL(arch_ftrace_ops_list_func);
7417 * If there's only one function registered but it does not support
7418 * recursion, needs RCU protection, then this function will be called
7419 * by the mcount trampoline.
7421 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
7422 struct ftrace_ops *op, struct ftrace_regs *fregs)
7426 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7430 if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
7431 op->func(ip, parent_ip, op, fregs);
7433 trace_clear_recursion(bit);
7435 NOKPROBE_SYMBOL(ftrace_ops_assist_func);
7438 * ftrace_ops_get_func - get the function a trampoline should call
7439 * @ops: the ops to get the function for
7441 * Normally the mcount trampoline will call the ops->func, but there
7442 * are times that it should not. For example, if the ops does not
7443 * have its own recursion protection, then it should call the
7444 * ftrace_ops_assist_func() instead.
7446 * Returns the function that the trampoline should call for @ops.
7448 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
7451 * If the function does not handle recursion or needs to be RCU safe,
7452 * then we need to call the assist handler.
7454 if (ops->flags & (FTRACE_OPS_FL_RECURSION |
7456 return ftrace_ops_assist_func;
7462 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
7463 struct task_struct *prev,
7464 struct task_struct *next,
7465 unsigned int prev_state)
7467 struct trace_array *tr = data;
7468 struct trace_pid_list *pid_list;
7469 struct trace_pid_list *no_pid_list;
7471 pid_list = rcu_dereference_sched(tr->function_pids);
7472 no_pid_list = rcu_dereference_sched(tr->function_no_pids);
7474 if (trace_ignore_this_task(pid_list, no_pid_list, next))
7475 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7478 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7483 ftrace_pid_follow_sched_process_fork(void *data,
7484 struct task_struct *self,
7485 struct task_struct *task)
7487 struct trace_pid_list *pid_list;
7488 struct trace_array *tr = data;
7490 pid_list = rcu_dereference_sched(tr->function_pids);
7491 trace_filter_add_remove_task(pid_list, self, task);
7493 pid_list = rcu_dereference_sched(tr->function_no_pids);
7494 trace_filter_add_remove_task(pid_list, self, task);
7498 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
7500 struct trace_pid_list *pid_list;
7501 struct trace_array *tr = data;
7503 pid_list = rcu_dereference_sched(tr->function_pids);
7504 trace_filter_add_remove_task(pid_list, NULL, task);
7506 pid_list = rcu_dereference_sched(tr->function_no_pids);
7507 trace_filter_add_remove_task(pid_list, NULL, task);
7510 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
7513 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7515 register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7518 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7520 unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7525 static void clear_ftrace_pids(struct trace_array *tr, int type)
7527 struct trace_pid_list *pid_list;
7528 struct trace_pid_list *no_pid_list;
7531 pid_list = rcu_dereference_protected(tr->function_pids,
7532 lockdep_is_held(&ftrace_lock));
7533 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7534 lockdep_is_held(&ftrace_lock));
7536 /* Make sure there's something to do */
7537 if (!pid_type_enabled(type, pid_list, no_pid_list))
7540 /* See if the pids still need to be checked after this */
7541 if (!still_need_pid_events(type, pid_list, no_pid_list)) {
7542 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7543 for_each_possible_cpu(cpu)
7544 per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
7547 if (type & TRACE_PIDS)
7548 rcu_assign_pointer(tr->function_pids, NULL);
7550 if (type & TRACE_NO_PIDS)
7551 rcu_assign_pointer(tr->function_no_pids, NULL);
7553 /* Wait till all users are no longer using pid filtering */
7556 if ((type & TRACE_PIDS) && pid_list)
7557 trace_pid_list_free(pid_list);
7559 if ((type & TRACE_NO_PIDS) && no_pid_list)
7560 trace_pid_list_free(no_pid_list);
7563 void ftrace_clear_pids(struct trace_array *tr)
7565 mutex_lock(&ftrace_lock);
7567 clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
7569 mutex_unlock(&ftrace_lock);
7572 static void ftrace_pid_reset(struct trace_array *tr, int type)
7574 mutex_lock(&ftrace_lock);
7575 clear_ftrace_pids(tr, type);
7577 ftrace_update_pid_func();
7578 ftrace_startup_all(0);
7580 mutex_unlock(&ftrace_lock);
7583 /* Greater than any max PID */
7584 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
7586 static void *fpid_start(struct seq_file *m, loff_t *pos)
7589 struct trace_pid_list *pid_list;
7590 struct trace_array *tr = m->private;
7592 mutex_lock(&ftrace_lock);
7593 rcu_read_lock_sched();
7595 pid_list = rcu_dereference_sched(tr->function_pids);
7598 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7600 return trace_pid_start(pid_list, pos);
7603 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
7605 struct trace_array *tr = m->private;
7606 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
7608 if (v == FTRACE_NO_PIDS) {
7612 return trace_pid_next(pid_list, v, pos);
7615 static void fpid_stop(struct seq_file *m, void *p)
7618 rcu_read_unlock_sched();
7619 mutex_unlock(&ftrace_lock);
7622 static int fpid_show(struct seq_file *m, void *v)
7624 if (v == FTRACE_NO_PIDS) {
7625 seq_puts(m, "no pid\n");
7629 return trace_pid_show(m, v);
7632 static const struct seq_operations ftrace_pid_sops = {
7633 .start = fpid_start,
7639 static void *fnpid_start(struct seq_file *m, loff_t *pos)
7642 struct trace_pid_list *pid_list;
7643 struct trace_array *tr = m->private;
7645 mutex_lock(&ftrace_lock);
7646 rcu_read_lock_sched();
7648 pid_list = rcu_dereference_sched(tr->function_no_pids);
7651 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7653 return trace_pid_start(pid_list, pos);
7656 static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
7658 struct trace_array *tr = m->private;
7659 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
7661 if (v == FTRACE_NO_PIDS) {
7665 return trace_pid_next(pid_list, v, pos);
7668 static const struct seq_operations ftrace_no_pid_sops = {
7669 .start = fnpid_start,
7675 static int pid_open(struct inode *inode, struct file *file, int type)
7677 const struct seq_operations *seq_ops;
7678 struct trace_array *tr = inode->i_private;
7682 ret = tracing_check_open_get_tr(tr);
7686 if ((file->f_mode & FMODE_WRITE) &&
7687 (file->f_flags & O_TRUNC))
7688 ftrace_pid_reset(tr, type);
7692 seq_ops = &ftrace_pid_sops;
7695 seq_ops = &ftrace_no_pid_sops;
7698 trace_array_put(tr);
7703 ret = seq_open(file, seq_ops);
7705 trace_array_put(tr);
7707 m = file->private_data;
7708 /* copy tr over to seq ops */
7716 ftrace_pid_open(struct inode *inode, struct file *file)
7718 return pid_open(inode, file, TRACE_PIDS);
7722 ftrace_no_pid_open(struct inode *inode, struct file *file)
7724 return pid_open(inode, file, TRACE_NO_PIDS);
7727 static void ignore_task_cpu(void *data)
7729 struct trace_array *tr = data;
7730 struct trace_pid_list *pid_list;
7731 struct trace_pid_list *no_pid_list;
7734 * This function is called by on_each_cpu() while the
7735 * event_mutex is held.
7737 pid_list = rcu_dereference_protected(tr->function_pids,
7738 mutex_is_locked(&ftrace_lock));
7739 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7740 mutex_is_locked(&ftrace_lock));
7742 if (trace_ignore_this_task(pid_list, no_pid_list, current))
7743 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7746 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7751 pid_write(struct file *filp, const char __user *ubuf,
7752 size_t cnt, loff_t *ppos, int type)
7754 struct seq_file *m = filp->private_data;
7755 struct trace_array *tr = m->private;
7756 struct trace_pid_list *filtered_pids;
7757 struct trace_pid_list *other_pids;
7758 struct trace_pid_list *pid_list;
7764 mutex_lock(&ftrace_lock);
7768 filtered_pids = rcu_dereference_protected(tr->function_pids,
7769 lockdep_is_held(&ftrace_lock));
7770 other_pids = rcu_dereference_protected(tr->function_no_pids,
7771 lockdep_is_held(&ftrace_lock));
7774 filtered_pids = rcu_dereference_protected(tr->function_no_pids,
7775 lockdep_is_held(&ftrace_lock));
7776 other_pids = rcu_dereference_protected(tr->function_pids,
7777 lockdep_is_held(&ftrace_lock));
7785 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
7791 rcu_assign_pointer(tr->function_pids, pid_list);
7794 rcu_assign_pointer(tr->function_no_pids, pid_list);
7799 if (filtered_pids) {
7801 trace_pid_list_free(filtered_pids);
7802 } else if (pid_list && !other_pids) {
7803 /* Register a probe to set whether to ignore the tracing of a task */
7804 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7808 * Ignoring of pids is done at task switch. But we have to
7809 * check for those tasks that are currently running.
7810 * Always do this in case a pid was appended or removed.
7812 on_each_cpu(ignore_task_cpu, tr, 1);
7814 ftrace_update_pid_func();
7815 ftrace_startup_all(0);
7817 mutex_unlock(&ftrace_lock);
7826 ftrace_pid_write(struct file *filp, const char __user *ubuf,
7827 size_t cnt, loff_t *ppos)
7829 return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
7833 ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
7834 size_t cnt, loff_t *ppos)
7836 return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
7840 ftrace_pid_release(struct inode *inode, struct file *file)
7842 struct trace_array *tr = inode->i_private;
7844 trace_array_put(tr);
7846 return seq_release(inode, file);
7849 static const struct file_operations ftrace_pid_fops = {
7850 .open = ftrace_pid_open,
7851 .write = ftrace_pid_write,
7853 .llseek = tracing_lseek,
7854 .release = ftrace_pid_release,
7857 static const struct file_operations ftrace_no_pid_fops = {
7858 .open = ftrace_no_pid_open,
7859 .write = ftrace_no_pid_write,
7861 .llseek = tracing_lseek,
7862 .release = ftrace_pid_release,
7865 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
7867 trace_create_file("set_ftrace_pid", TRACE_MODE_WRITE, d_tracer,
7868 tr, &ftrace_pid_fops);
7869 trace_create_file("set_ftrace_notrace_pid", TRACE_MODE_WRITE,
7870 d_tracer, tr, &ftrace_no_pid_fops);
7873 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
7874 struct dentry *d_tracer)
7876 /* Only the top level directory has the dyn_tracefs and profile */
7877 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
7879 ftrace_init_dyn_tracefs(d_tracer);
7880 ftrace_profile_tracefs(d_tracer);
7884 * ftrace_kill - kill ftrace
7886 * This function should be used by panic code. It stops ftrace
7887 * but in a not so nice way. If you need to simply kill ftrace
7888 * from a non-atomic section, use ftrace_kill.
7890 void ftrace_kill(void)
7892 ftrace_disabled = 1;
7894 ftrace_trace_function = ftrace_stub;
7898 * ftrace_is_dead - Test if ftrace is dead or not.
7900 * Returns 1 if ftrace is "dead", zero otherwise.
7902 int ftrace_is_dead(void)
7904 return ftrace_disabled;
7907 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
7909 * When registering ftrace_ops with IPMODIFY, it is necessary to make sure
7910 * it doesn't conflict with any direct ftrace_ops. If there is existing
7911 * direct ftrace_ops on a kernel function being patched, call
7912 * FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER on it to enable sharing.
7914 * @ops: ftrace_ops being registered.
7918 * Negative on failure.
7920 static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
7922 struct ftrace_func_entry *entry;
7923 struct ftrace_hash *hash;
7924 struct ftrace_ops *op;
7927 lockdep_assert_held_once(&direct_mutex);
7929 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
7932 hash = ops->func_hash->filter_hash;
7933 size = 1 << hash->size_bits;
7934 for (i = 0; i < size; i++) {
7935 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
7936 unsigned long ip = entry->ip;
7937 bool found_op = false;
7939 mutex_lock(&ftrace_lock);
7940 do_for_each_ftrace_op(op, ftrace_ops_list) {
7941 if (!(op->flags & FTRACE_OPS_FL_DIRECT))
7943 if (ops_references_ip(op, ip)) {
7947 } while_for_each_ftrace_op(op);
7948 mutex_unlock(&ftrace_lock);
7954 ret = op->ops_func(op, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER);
7965 * Similar to prepare_direct_functions_for_ipmodify, clean up after ops
7966 * with IPMODIFY is unregistered. The cleanup is optional for most DIRECT
7969 static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
7971 struct ftrace_func_entry *entry;
7972 struct ftrace_hash *hash;
7973 struct ftrace_ops *op;
7976 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
7979 mutex_lock(&direct_mutex);
7981 hash = ops->func_hash->filter_hash;
7982 size = 1 << hash->size_bits;
7983 for (i = 0; i < size; i++) {
7984 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
7985 unsigned long ip = entry->ip;
7986 bool found_op = false;
7988 mutex_lock(&ftrace_lock);
7989 do_for_each_ftrace_op(op, ftrace_ops_list) {
7990 if (!(op->flags & FTRACE_OPS_FL_DIRECT))
7992 if (ops_references_ip(op, ip)) {
7996 } while_for_each_ftrace_op(op);
7997 mutex_unlock(&ftrace_lock);
7999 /* The cleanup is optional, ignore any errors */
8000 if (found_op && op->ops_func)
8001 op->ops_func(op, FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER);
8004 mutex_unlock(&direct_mutex);
8007 #define lock_direct_mutex() mutex_lock(&direct_mutex)
8008 #define unlock_direct_mutex() mutex_unlock(&direct_mutex)
8010 #else /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
8012 static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
8017 static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
8021 #define lock_direct_mutex() do { } while (0)
8022 #define unlock_direct_mutex() do { } while (0)
8024 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
8027 * Similar to register_ftrace_function, except we don't lock direct_mutex.
8029 static int register_ftrace_function_nolock(struct ftrace_ops *ops)
8033 ftrace_ops_init(ops);
8035 mutex_lock(&ftrace_lock);
8037 ret = ftrace_startup(ops, 0);
8039 mutex_unlock(&ftrace_lock);
8045 * register_ftrace_function - register a function for profiling
8046 * @ops: ops structure that holds the function for profiling.
8048 * Register a function to be called by all functions in the
8051 * Note: @ops->func and all the functions it calls must be labeled
8052 * with "notrace", otherwise it will go into a
8055 int register_ftrace_function(struct ftrace_ops *ops)
8059 lock_direct_mutex();
8060 ret = prepare_direct_functions_for_ipmodify(ops);
8064 ret = register_ftrace_function_nolock(ops);
8067 unlock_direct_mutex();
8070 EXPORT_SYMBOL_GPL(register_ftrace_function);
8073 * unregister_ftrace_function - unregister a function for profiling.
8074 * @ops: ops structure that holds the function to unregister
8076 * Unregister a function that was added to be called by ftrace profiling.
8078 int unregister_ftrace_function(struct ftrace_ops *ops)
8082 mutex_lock(&ftrace_lock);
8083 ret = ftrace_shutdown(ops, 0);
8084 mutex_unlock(&ftrace_lock);
8086 cleanup_direct_functions_after_ipmodify(ops);
8089 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
8091 static int symbols_cmp(const void *a, const void *b)
8093 const char **str_a = (const char **) a;
8094 const char **str_b = (const char **) b;
8096 return strcmp(*str_a, *str_b);
8099 struct kallsyms_data {
8100 unsigned long *addrs;
8106 /* This function gets called for all kernel and module symbols
8107 * and returns 1 in case we resolved all the requested symbols,
8110 static int kallsyms_callback(void *data, const char *name, unsigned long addr)
8112 struct kallsyms_data *args = data;
8116 sym = bsearch(&name, args->syms, args->cnt, sizeof(*args->syms), symbols_cmp);
8120 idx = sym - args->syms;
8121 if (args->addrs[idx])
8124 if (!ftrace_location(addr))
8127 args->addrs[idx] = addr;
8129 return args->found == args->cnt ? 1 : 0;
8133 * ftrace_lookup_symbols - Lookup addresses for array of symbols
8135 * @sorted_syms: array of symbols pointers symbols to resolve,
8136 * must be alphabetically sorted
8137 * @cnt: number of symbols/addresses in @syms/@addrs arrays
8138 * @addrs: array for storing resulting addresses
8140 * This function looks up addresses for array of symbols provided in
8141 * @syms array (must be alphabetically sorted) and stores them in
8142 * @addrs array, which needs to be big enough to store at least @cnt
8145 * This function returns 0 if all provided symbols are found,
8148 int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
8150 struct kallsyms_data args;
8153 memset(addrs, 0, sizeof(*addrs) * cnt);
8155 args.syms = sorted_syms;
8159 found_all = kallsyms_on_each_symbol(kallsyms_callback, &args);
8162 found_all = module_kallsyms_on_each_symbol(NULL, kallsyms_callback, &args);
8163 return found_all ? 0 : -ESRCH;
8166 #ifdef CONFIG_SYSCTL
8168 #ifdef CONFIG_DYNAMIC_FTRACE
8169 static void ftrace_startup_sysctl(void)
8173 if (unlikely(ftrace_disabled))
8176 /* Force update next time */
8177 saved_ftrace_func = NULL;
8178 /* ftrace_start_up is true if we want ftrace running */
8179 if (ftrace_start_up) {
8180 command = FTRACE_UPDATE_CALLS;
8181 if (ftrace_graph_active)
8182 command |= FTRACE_START_FUNC_RET;
8183 ftrace_startup_enable(command);
8187 static void ftrace_shutdown_sysctl(void)
8191 if (unlikely(ftrace_disabled))
8194 /* ftrace_start_up is true if ftrace is running */
8195 if (ftrace_start_up) {
8196 command = FTRACE_DISABLE_CALLS;
8197 if (ftrace_graph_active)
8198 command |= FTRACE_STOP_FUNC_RET;
8199 ftrace_run_update_code(command);
8203 # define ftrace_startup_sysctl() do { } while (0)
8204 # define ftrace_shutdown_sysctl() do { } while (0)
8205 #endif /* CONFIG_DYNAMIC_FTRACE */
8207 static bool is_permanent_ops_registered(void)
8209 struct ftrace_ops *op;
8211 do_for_each_ftrace_op(op, ftrace_ops_list) {
8212 if (op->flags & FTRACE_OPS_FL_PERMANENT)
8214 } while_for_each_ftrace_op(op);
8220 ftrace_enable_sysctl(struct ctl_table *table, int write,
8221 void *buffer, size_t *lenp, loff_t *ppos)
8225 mutex_lock(&ftrace_lock);
8227 if (unlikely(ftrace_disabled))
8230 ret = proc_dointvec(table, write, buffer, lenp, ppos);
8232 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
8235 if (ftrace_enabled) {
8237 /* we are starting ftrace again */
8238 if (rcu_dereference_protected(ftrace_ops_list,
8239 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
8240 update_ftrace_function();
8242 ftrace_startup_sysctl();
8245 if (is_permanent_ops_registered()) {
8246 ftrace_enabled = true;
8251 /* stopping ftrace calls (just send to ftrace_stub) */
8252 ftrace_trace_function = ftrace_stub;
8254 ftrace_shutdown_sysctl();
8257 last_ftrace_enabled = !!ftrace_enabled;
8259 mutex_unlock(&ftrace_lock);
8263 static struct ctl_table ftrace_sysctls[] = {
8265 .procname = "ftrace_enabled",
8266 .data = &ftrace_enabled,
8267 .maxlen = sizeof(int),
8269 .proc_handler = ftrace_enable_sysctl,
8274 static int __init ftrace_sysctl_init(void)
8276 register_sysctl_init("kernel", ftrace_sysctls);
8279 late_initcall(ftrace_sysctl_init);