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 #define FTRACE_INVALID_FUNCTION "__ftrace_invalid_address__"
50 #define FTRACE_WARN_ON(cond) \
58 #define FTRACE_WARN_ON_ONCE(cond) \
61 if (WARN_ON_ONCE(___r)) \
66 /* hash bits for specific function selection */
67 #define FTRACE_HASH_DEFAULT_BITS 10
68 #define FTRACE_HASH_MAX_BITS 12
70 #ifdef CONFIG_DYNAMIC_FTRACE
71 #define INIT_OPS_HASH(opsname) \
72 .func_hash = &opsname.local_hash, \
73 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
75 #define INIT_OPS_HASH(opsname)
79 FTRACE_MODIFY_ENABLE_FL = (1 << 0),
80 FTRACE_MODIFY_MAY_SLEEP_FL = (1 << 1),
83 struct ftrace_ops ftrace_list_end __read_mostly = {
85 .flags = FTRACE_OPS_FL_STUB,
86 INIT_OPS_HASH(ftrace_list_end)
89 /* ftrace_enabled is a method to turn ftrace on or off */
90 int ftrace_enabled __read_mostly;
91 static int __maybe_unused last_ftrace_enabled;
93 /* Current function tracing op */
94 struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
95 /* What to set function_trace_op to */
96 static struct ftrace_ops *set_function_trace_op;
98 static bool ftrace_pids_enabled(struct ftrace_ops *ops)
100 struct trace_array *tr;
102 if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
107 return tr->function_pids != NULL || tr->function_no_pids != NULL;
110 static void ftrace_update_trampoline(struct ftrace_ops *ops);
113 * ftrace_disabled is set when an anomaly is discovered.
114 * ftrace_disabled is much stronger than ftrace_enabled.
116 static int ftrace_disabled __read_mostly;
118 DEFINE_MUTEX(ftrace_lock);
120 struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
121 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
122 struct ftrace_ops global_ops;
124 /* Defined by vmlinux.lds.h see the comment above arch_ftrace_ops_list_func for details */
125 void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
126 struct ftrace_ops *op, struct ftrace_regs *fregs);
128 static inline void ftrace_ops_init(struct ftrace_ops *ops)
130 #ifdef CONFIG_DYNAMIC_FTRACE
131 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
132 mutex_init(&ops->local_hash.regex_lock);
133 ops->func_hash = &ops->local_hash;
134 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
139 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
140 struct ftrace_ops *op, struct ftrace_regs *fregs)
142 struct trace_array *tr = op->private;
146 pid = this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid);
147 if (pid == FTRACE_PID_IGNORE)
149 if (pid != FTRACE_PID_TRACE &&
154 op->saved_func(ip, parent_ip, op, fregs);
157 static void ftrace_sync_ipi(void *data)
159 /* Probably not needed, but do it anyway */
163 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
166 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
167 * then it needs to call the list anyway.
169 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
170 FTRACE_FORCE_LIST_FUNC)
171 return ftrace_ops_list_func;
173 return ftrace_ops_get_func(ops);
176 static void update_ftrace_function(void)
181 * Prepare the ftrace_ops that the arch callback will use.
182 * If there's only one ftrace_ops registered, the ftrace_ops_list
183 * will point to the ops we want.
185 set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
186 lockdep_is_held(&ftrace_lock));
188 /* If there's no ftrace_ops registered, just call the stub function */
189 if (set_function_trace_op == &ftrace_list_end) {
193 * If we are at the end of the list and this ops is
194 * recursion safe and not dynamic and the arch supports passing ops,
195 * then have the mcount trampoline call the function directly.
197 } else if (rcu_dereference_protected(ftrace_ops_list->next,
198 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
199 func = ftrace_ops_get_list_func(ftrace_ops_list);
202 /* Just use the default ftrace_ops */
203 set_function_trace_op = &ftrace_list_end;
204 func = ftrace_ops_list_func;
207 update_function_graph_func();
209 /* If there's no change, then do nothing more here */
210 if (ftrace_trace_function == func)
214 * If we are using the list function, it doesn't care
215 * about the function_trace_ops.
217 if (func == ftrace_ops_list_func) {
218 ftrace_trace_function = func;
220 * Don't even bother setting function_trace_ops,
221 * it would be racy to do so anyway.
226 #ifndef CONFIG_DYNAMIC_FTRACE
228 * For static tracing, we need to be a bit more careful.
229 * The function change takes affect immediately. Thus,
230 * we need to coordinate the setting of the function_trace_ops
231 * with the setting of the ftrace_trace_function.
233 * Set the function to the list ops, which will call the
234 * function we want, albeit indirectly, but it handles the
235 * ftrace_ops and doesn't depend on function_trace_op.
237 ftrace_trace_function = ftrace_ops_list_func;
239 * Make sure all CPUs see this. Yes this is slow, but static
240 * tracing is slow and nasty to have enabled.
242 synchronize_rcu_tasks_rude();
243 /* Now all cpus are using the list ops. */
244 function_trace_op = set_function_trace_op;
245 /* Make sure the function_trace_op is visible on all CPUs */
247 /* Nasty way to force a rmb on all cpus */
248 smp_call_function(ftrace_sync_ipi, NULL, 1);
249 /* OK, we are all set to update the ftrace_trace_function now! */
250 #endif /* !CONFIG_DYNAMIC_FTRACE */
252 ftrace_trace_function = func;
255 static void add_ftrace_ops(struct ftrace_ops __rcu **list,
256 struct ftrace_ops *ops)
258 rcu_assign_pointer(ops->next, *list);
261 * We are entering ops into the list but another
262 * CPU might be walking that list. We need to make sure
263 * the ops->next pointer is valid before another CPU sees
264 * the ops pointer included into the list.
266 rcu_assign_pointer(*list, ops);
269 static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
270 struct ftrace_ops *ops)
272 struct ftrace_ops **p;
275 * If we are removing the last function, then simply point
276 * to the ftrace_stub.
278 if (rcu_dereference_protected(*list,
279 lockdep_is_held(&ftrace_lock)) == ops &&
280 rcu_dereference_protected(ops->next,
281 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
282 *list = &ftrace_list_end;
286 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
297 static void ftrace_update_trampoline(struct ftrace_ops *ops);
299 int __register_ftrace_function(struct ftrace_ops *ops)
301 if (ops->flags & FTRACE_OPS_FL_DELETED)
304 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
307 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
309 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
310 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
311 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
313 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
314 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
317 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
318 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
320 if (!ftrace_enabled && (ops->flags & FTRACE_OPS_FL_PERMANENT))
323 if (!is_kernel_core_data((unsigned long)ops))
324 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
326 add_ftrace_ops(&ftrace_ops_list, ops);
328 /* Always save the function, and reset at unregistering */
329 ops->saved_func = ops->func;
331 if (ftrace_pids_enabled(ops))
332 ops->func = ftrace_pid_func;
334 ftrace_update_trampoline(ops);
337 update_ftrace_function();
342 int __unregister_ftrace_function(struct ftrace_ops *ops)
346 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
349 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
355 update_ftrace_function();
357 ops->func = ops->saved_func;
362 static void ftrace_update_pid_func(void)
364 struct ftrace_ops *op;
366 /* Only do something if we are tracing something */
367 if (ftrace_trace_function == ftrace_stub)
370 do_for_each_ftrace_op(op, ftrace_ops_list) {
371 if (op->flags & FTRACE_OPS_FL_PID) {
372 op->func = ftrace_pids_enabled(op) ?
373 ftrace_pid_func : op->saved_func;
374 ftrace_update_trampoline(op);
376 } while_for_each_ftrace_op(op);
378 update_ftrace_function();
381 #ifdef CONFIG_FUNCTION_PROFILER
382 struct ftrace_profile {
383 struct hlist_node node;
385 unsigned long counter;
386 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
387 unsigned long long time;
388 unsigned long long time_squared;
392 struct ftrace_profile_page {
393 struct ftrace_profile_page *next;
395 struct ftrace_profile records[];
398 struct ftrace_profile_stat {
400 struct hlist_head *hash;
401 struct ftrace_profile_page *pages;
402 struct ftrace_profile_page *start;
403 struct tracer_stat stat;
406 #define PROFILE_RECORDS_SIZE \
407 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
409 #define PROFILES_PER_PAGE \
410 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
412 static int ftrace_profile_enabled __read_mostly;
414 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
415 static DEFINE_MUTEX(ftrace_profile_lock);
417 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
419 #define FTRACE_PROFILE_HASH_BITS 10
420 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
423 function_stat_next(void *v, int idx)
425 struct ftrace_profile *rec = v;
426 struct ftrace_profile_page *pg;
428 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
434 if ((void *)rec >= (void *)&pg->records[pg->index]) {
438 rec = &pg->records[0];
446 static void *function_stat_start(struct tracer_stat *trace)
448 struct ftrace_profile_stat *stat =
449 container_of(trace, struct ftrace_profile_stat, stat);
451 if (!stat || !stat->start)
454 return function_stat_next(&stat->start->records[0], 0);
457 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
458 /* function graph compares on total time */
459 static int function_stat_cmp(const void *p1, const void *p2)
461 const struct ftrace_profile *a = p1;
462 const struct ftrace_profile *b = p2;
464 if (a->time < b->time)
466 if (a->time > b->time)
472 /* not function graph compares against hits */
473 static int function_stat_cmp(const void *p1, const void *p2)
475 const struct ftrace_profile *a = p1;
476 const struct ftrace_profile *b = p2;
478 if (a->counter < b->counter)
480 if (a->counter > b->counter)
487 static int function_stat_headers(struct seq_file *m)
489 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
490 seq_puts(m, " Function "
493 "--- ---- --- ---\n");
495 seq_puts(m, " Function Hit\n"
501 static int function_stat_show(struct seq_file *m, void *v)
503 struct ftrace_profile *rec = v;
504 char str[KSYM_SYMBOL_LEN];
506 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
507 static struct trace_seq s;
508 unsigned long long avg;
509 unsigned long long stddev;
511 mutex_lock(&ftrace_profile_lock);
513 /* we raced with function_profile_reset() */
514 if (unlikely(rec->counter == 0)) {
519 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
520 avg = div64_ul(rec->time, rec->counter);
521 if (tracing_thresh && (avg < tracing_thresh))
525 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
526 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
528 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
531 /* Sample standard deviation (s^2) */
532 if (rec->counter <= 1)
536 * Apply Welford's method:
537 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
539 stddev = rec->counter * rec->time_squared -
540 rec->time * rec->time;
543 * Divide only 1000 for ns^2 -> us^2 conversion.
544 * trace_print_graph_duration will divide 1000 again.
546 stddev = div64_ul(stddev,
547 rec->counter * (rec->counter - 1) * 1000);
551 trace_print_graph_duration(rec->time, &s);
552 trace_seq_puts(&s, " ");
553 trace_print_graph_duration(avg, &s);
554 trace_seq_puts(&s, " ");
555 trace_print_graph_duration(stddev, &s);
556 trace_print_seq(m, &s);
560 mutex_unlock(&ftrace_profile_lock);
565 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
567 struct ftrace_profile_page *pg;
569 pg = stat->pages = stat->start;
572 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
577 memset(stat->hash, 0,
578 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
581 static int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
583 struct ftrace_profile_page *pg;
588 /* If we already allocated, do nothing */
592 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
596 #ifdef CONFIG_DYNAMIC_FTRACE
597 functions = ftrace_update_tot_cnt;
600 * We do not know the number of functions that exist because
601 * dynamic tracing is what counts them. With past experience
602 * we have around 20K functions. That should be more than enough.
603 * It is highly unlikely we will execute every function in
609 pg = stat->start = stat->pages;
611 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
613 for (i = 1; i < pages; i++) {
614 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
625 unsigned long tmp = (unsigned long)pg;
637 static int ftrace_profile_init_cpu(int cpu)
639 struct ftrace_profile_stat *stat;
642 stat = &per_cpu(ftrace_profile_stats, cpu);
645 /* If the profile is already created, simply reset it */
646 ftrace_profile_reset(stat);
651 * We are profiling all functions, but usually only a few thousand
652 * functions are hit. We'll make a hash of 1024 items.
654 size = FTRACE_PROFILE_HASH_SIZE;
656 stat->hash = kcalloc(size, sizeof(struct hlist_head), GFP_KERNEL);
661 /* Preallocate the function profiling pages */
662 if (ftrace_profile_pages_init(stat) < 0) {
671 static int ftrace_profile_init(void)
676 for_each_possible_cpu(cpu) {
677 ret = ftrace_profile_init_cpu(cpu);
685 /* interrupts must be disabled */
686 static struct ftrace_profile *
687 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
689 struct ftrace_profile *rec;
690 struct hlist_head *hhd;
693 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
694 hhd = &stat->hash[key];
696 if (hlist_empty(hhd))
699 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
707 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
708 struct ftrace_profile *rec)
712 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
713 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
717 * The memory is already allocated, this simply finds a new record to use.
719 static struct ftrace_profile *
720 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
722 struct ftrace_profile *rec = NULL;
724 /* prevent recursion (from NMIs) */
725 if (atomic_inc_return(&stat->disabled) != 1)
729 * Try to find the function again since an NMI
730 * could have added it
732 rec = ftrace_find_profiled_func(stat, ip);
736 if (stat->pages->index == PROFILES_PER_PAGE) {
737 if (!stat->pages->next)
739 stat->pages = stat->pages->next;
742 rec = &stat->pages->records[stat->pages->index++];
744 ftrace_add_profile(stat, rec);
747 atomic_dec(&stat->disabled);
753 function_profile_call(unsigned long ip, unsigned long parent_ip,
754 struct ftrace_ops *ops, struct ftrace_regs *fregs)
756 struct ftrace_profile_stat *stat;
757 struct ftrace_profile *rec;
760 if (!ftrace_profile_enabled)
763 local_irq_save(flags);
765 stat = this_cpu_ptr(&ftrace_profile_stats);
766 if (!stat->hash || !ftrace_profile_enabled)
769 rec = ftrace_find_profiled_func(stat, ip);
771 rec = ftrace_profile_alloc(stat, ip);
778 local_irq_restore(flags);
781 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
782 static bool fgraph_graph_time = true;
784 void ftrace_graph_graph_time_control(bool enable)
786 fgraph_graph_time = enable;
789 static int profile_graph_entry(struct ftrace_graph_ent *trace)
791 struct ftrace_ret_stack *ret_stack;
793 function_profile_call(trace->func, 0, NULL, NULL);
795 /* If function graph is shutting down, ret_stack can be NULL */
796 if (!current->ret_stack)
799 ret_stack = ftrace_graph_get_ret_stack(current, 0);
801 ret_stack->subtime = 0;
806 static void profile_graph_return(struct ftrace_graph_ret *trace)
808 struct ftrace_ret_stack *ret_stack;
809 struct ftrace_profile_stat *stat;
810 unsigned long long calltime;
811 struct ftrace_profile *rec;
814 local_irq_save(flags);
815 stat = this_cpu_ptr(&ftrace_profile_stats);
816 if (!stat->hash || !ftrace_profile_enabled)
819 /* If the calltime was zero'd ignore it */
820 if (!trace->calltime)
823 calltime = trace->rettime - trace->calltime;
825 if (!fgraph_graph_time) {
827 /* Append this call time to the parent time to subtract */
828 ret_stack = ftrace_graph_get_ret_stack(current, 1);
830 ret_stack->subtime += calltime;
832 ret_stack = ftrace_graph_get_ret_stack(current, 0);
833 if (ret_stack && ret_stack->subtime < calltime)
834 calltime -= ret_stack->subtime;
839 rec = ftrace_find_profiled_func(stat, trace->func);
841 rec->time += calltime;
842 rec->time_squared += calltime * calltime;
846 local_irq_restore(flags);
849 static struct fgraph_ops fprofiler_ops = {
850 .entryfunc = &profile_graph_entry,
851 .retfunc = &profile_graph_return,
854 static int register_ftrace_profiler(void)
856 return register_ftrace_graph(&fprofiler_ops);
859 static void unregister_ftrace_profiler(void)
861 unregister_ftrace_graph(&fprofiler_ops);
864 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
865 .func = function_profile_call,
866 .flags = FTRACE_OPS_FL_INITIALIZED,
867 INIT_OPS_HASH(ftrace_profile_ops)
870 static int register_ftrace_profiler(void)
872 return register_ftrace_function(&ftrace_profile_ops);
875 static void unregister_ftrace_profiler(void)
877 unregister_ftrace_function(&ftrace_profile_ops);
879 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
882 ftrace_profile_write(struct file *filp, const char __user *ubuf,
883 size_t cnt, loff_t *ppos)
888 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
894 mutex_lock(&ftrace_profile_lock);
895 if (ftrace_profile_enabled ^ val) {
897 ret = ftrace_profile_init();
903 ret = register_ftrace_profiler();
908 ftrace_profile_enabled = 1;
910 ftrace_profile_enabled = 0;
912 * unregister_ftrace_profiler calls stop_machine
913 * so this acts like an synchronize_rcu.
915 unregister_ftrace_profiler();
919 mutex_unlock(&ftrace_profile_lock);
927 ftrace_profile_read(struct file *filp, char __user *ubuf,
928 size_t cnt, loff_t *ppos)
930 char buf[64]; /* big enough to hold a number */
933 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
934 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
937 static const struct file_operations ftrace_profile_fops = {
938 .open = tracing_open_generic,
939 .read = ftrace_profile_read,
940 .write = ftrace_profile_write,
941 .llseek = default_llseek,
944 /* used to initialize the real stat files */
945 static struct tracer_stat function_stats __initdata = {
947 .stat_start = function_stat_start,
948 .stat_next = function_stat_next,
949 .stat_cmp = function_stat_cmp,
950 .stat_headers = function_stat_headers,
951 .stat_show = function_stat_show
954 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
956 struct ftrace_profile_stat *stat;
961 for_each_possible_cpu(cpu) {
962 stat = &per_cpu(ftrace_profile_stats, cpu);
964 name = kasprintf(GFP_KERNEL, "function%d", cpu);
967 * The files created are permanent, if something happens
968 * we still do not free memory.
971 "Could not allocate stat file for cpu %d\n",
975 stat->stat = function_stats;
976 stat->stat.name = name;
977 ret = register_stat_tracer(&stat->stat);
980 "Could not register function stat for cpu %d\n",
987 trace_create_file("function_profile_enabled",
988 TRACE_MODE_WRITE, d_tracer, NULL,
989 &ftrace_profile_fops);
992 #else /* CONFIG_FUNCTION_PROFILER */
993 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
996 #endif /* CONFIG_FUNCTION_PROFILER */
998 #ifdef CONFIG_DYNAMIC_FTRACE
1000 static struct ftrace_ops *removed_ops;
1003 * Set when doing a global update, like enabling all recs or disabling them.
1004 * It is not set when just updating a single ftrace_ops.
1006 static bool update_all_ops;
1008 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1009 # error Dynamic ftrace depends on MCOUNT_RECORD
1012 struct ftrace_func_probe {
1013 struct ftrace_probe_ops *probe_ops;
1014 struct ftrace_ops ops;
1015 struct trace_array *tr;
1016 struct list_head list;
1022 * We make these constant because no one should touch them,
1023 * but they are used as the default "empty hash", to avoid allocating
1024 * it all the time. These are in a read only section such that if
1025 * anyone does try to modify it, it will cause an exception.
1027 static const struct hlist_head empty_buckets[1];
1028 static const struct ftrace_hash empty_hash = {
1029 .buckets = (struct hlist_head *)empty_buckets,
1031 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1033 struct ftrace_ops global_ops = {
1034 .func = ftrace_stub,
1035 .local_hash.notrace_hash = EMPTY_HASH,
1036 .local_hash.filter_hash = EMPTY_HASH,
1037 INIT_OPS_HASH(global_ops)
1038 .flags = FTRACE_OPS_FL_INITIALIZED |
1043 * Used by the stack unwinder to know about dynamic ftrace trampolines.
1045 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
1047 struct ftrace_ops *op = NULL;
1050 * Some of the ops may be dynamically allocated,
1051 * they are freed after a synchronize_rcu().
1053 preempt_disable_notrace();
1055 do_for_each_ftrace_op(op, ftrace_ops_list) {
1057 * This is to check for dynamically allocated trampolines.
1058 * Trampolines that are in kernel text will have
1059 * core_kernel_text() return true.
1061 if (op->trampoline && op->trampoline_size)
1062 if (addr >= op->trampoline &&
1063 addr < op->trampoline + op->trampoline_size) {
1064 preempt_enable_notrace();
1067 } while_for_each_ftrace_op(op);
1068 preempt_enable_notrace();
1074 * This is used by __kernel_text_address() to return true if the
1075 * address is on a dynamically allocated trampoline that would
1076 * not return true for either core_kernel_text() or
1077 * is_module_text_address().
1079 bool is_ftrace_trampoline(unsigned long addr)
1081 return ftrace_ops_trampoline(addr) != NULL;
1084 struct ftrace_page {
1085 struct ftrace_page *next;
1086 struct dyn_ftrace *records;
1091 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1092 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1094 static struct ftrace_page *ftrace_pages_start;
1095 static struct ftrace_page *ftrace_pages;
1097 static __always_inline unsigned long
1098 ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1100 if (hash->size_bits > 0)
1101 return hash_long(ip, hash->size_bits);
1106 /* Only use this function if ftrace_hash_empty() has already been tested */
1107 static __always_inline struct ftrace_func_entry *
1108 __ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1111 struct ftrace_func_entry *entry;
1112 struct hlist_head *hhd;
1114 key = ftrace_hash_key(hash, ip);
1115 hhd = &hash->buckets[key];
1117 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1118 if (entry->ip == ip)
1125 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1126 * @hash: The hash to look at
1127 * @ip: The instruction pointer to test
1129 * Search a given @hash to see if a given instruction pointer (@ip)
1132 * Returns the entry that holds the @ip if found. NULL otherwise.
1134 struct ftrace_func_entry *
1135 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1137 if (ftrace_hash_empty(hash))
1140 return __ftrace_lookup_ip(hash, ip);
1143 static void __add_hash_entry(struct ftrace_hash *hash,
1144 struct ftrace_func_entry *entry)
1146 struct hlist_head *hhd;
1149 key = ftrace_hash_key(hash, entry->ip);
1150 hhd = &hash->buckets[key];
1151 hlist_add_head(&entry->hlist, hhd);
1155 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1157 struct ftrace_func_entry *entry;
1159 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1164 __add_hash_entry(hash, entry);
1170 free_hash_entry(struct ftrace_hash *hash,
1171 struct ftrace_func_entry *entry)
1173 hlist_del(&entry->hlist);
1179 remove_hash_entry(struct ftrace_hash *hash,
1180 struct ftrace_func_entry *entry)
1182 hlist_del_rcu(&entry->hlist);
1186 static void ftrace_hash_clear(struct ftrace_hash *hash)
1188 struct hlist_head *hhd;
1189 struct hlist_node *tn;
1190 struct ftrace_func_entry *entry;
1191 int size = 1 << hash->size_bits;
1197 for (i = 0; i < size; i++) {
1198 hhd = &hash->buckets[i];
1199 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1200 free_hash_entry(hash, entry);
1202 FTRACE_WARN_ON(hash->count);
1205 static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1207 list_del(&ftrace_mod->list);
1208 kfree(ftrace_mod->module);
1209 kfree(ftrace_mod->func);
1213 static void clear_ftrace_mod_list(struct list_head *head)
1215 struct ftrace_mod_load *p, *n;
1217 /* stack tracer isn't supported yet */
1221 mutex_lock(&ftrace_lock);
1222 list_for_each_entry_safe(p, n, head, list)
1224 mutex_unlock(&ftrace_lock);
1227 static void free_ftrace_hash(struct ftrace_hash *hash)
1229 if (!hash || hash == EMPTY_HASH)
1231 ftrace_hash_clear(hash);
1232 kfree(hash->buckets);
1236 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1238 struct ftrace_hash *hash;
1240 hash = container_of(rcu, struct ftrace_hash, rcu);
1241 free_ftrace_hash(hash);
1244 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1246 if (!hash || hash == EMPTY_HASH)
1248 call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
1251 void ftrace_free_filter(struct ftrace_ops *ops)
1253 ftrace_ops_init(ops);
1254 free_ftrace_hash(ops->func_hash->filter_hash);
1255 free_ftrace_hash(ops->func_hash->notrace_hash);
1258 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1260 struct ftrace_hash *hash;
1263 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1267 size = 1 << size_bits;
1268 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1270 if (!hash->buckets) {
1275 hash->size_bits = size_bits;
1281 static int ftrace_add_mod(struct trace_array *tr,
1282 const char *func, const char *module,
1285 struct ftrace_mod_load *ftrace_mod;
1286 struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1288 ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1292 ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1293 ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1294 ftrace_mod->enable = enable;
1296 if (!ftrace_mod->func || !ftrace_mod->module)
1299 list_add(&ftrace_mod->list, mod_head);
1304 free_ftrace_mod(ftrace_mod);
1309 static struct ftrace_hash *
1310 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1312 struct ftrace_func_entry *entry;
1313 struct ftrace_hash *new_hash;
1318 new_hash = alloc_ftrace_hash(size_bits);
1323 new_hash->flags = hash->flags;
1326 if (ftrace_hash_empty(hash))
1329 size = 1 << hash->size_bits;
1330 for (i = 0; i < size; i++) {
1331 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1332 ret = add_hash_entry(new_hash, entry->ip);
1338 FTRACE_WARN_ON(new_hash->count != hash->count);
1343 free_ftrace_hash(new_hash);
1348 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1350 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1352 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1353 struct ftrace_hash *new_hash);
1355 static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size)
1357 struct ftrace_func_entry *entry;
1358 struct ftrace_hash *new_hash;
1359 struct hlist_head *hhd;
1360 struct hlist_node *tn;
1365 * Use around half the size (max bit of it), but
1366 * a minimum of 2 is fine (as size of 0 or 1 both give 1 for bits).
1368 bits = fls(size / 2);
1370 /* Don't allocate too much */
1371 if (bits > FTRACE_HASH_MAX_BITS)
1372 bits = FTRACE_HASH_MAX_BITS;
1374 new_hash = alloc_ftrace_hash(bits);
1378 new_hash->flags = src->flags;
1380 size = 1 << src->size_bits;
1381 for (i = 0; i < size; i++) {
1382 hhd = &src->buckets[i];
1383 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1384 remove_hash_entry(src, entry);
1385 __add_hash_entry(new_hash, entry);
1391 static struct ftrace_hash *
1392 __ftrace_hash_move(struct ftrace_hash *src)
1394 int size = src->count;
1397 * If the new source is empty, just return the empty_hash.
1399 if (ftrace_hash_empty(src))
1402 return dup_hash(src, size);
1406 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1407 struct ftrace_hash **dst, struct ftrace_hash *src)
1409 struct ftrace_hash *new_hash;
1412 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1413 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1416 new_hash = __ftrace_hash_move(src);
1420 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1422 /* IPMODIFY should be updated only when filter_hash updating */
1423 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1425 free_ftrace_hash(new_hash);
1431 * Remove the current set, update the hash and add
1434 ftrace_hash_rec_disable_modify(ops, enable);
1436 rcu_assign_pointer(*dst, new_hash);
1438 ftrace_hash_rec_enable_modify(ops, enable);
1443 static bool hash_contains_ip(unsigned long ip,
1444 struct ftrace_ops_hash *hash)
1447 * The function record is a match if it exists in the filter
1448 * hash and not in the notrace hash. Note, an empty hash is
1449 * considered a match for the filter hash, but an empty
1450 * notrace hash is considered not in the notrace hash.
1452 return (ftrace_hash_empty(hash->filter_hash) ||
1453 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1454 (ftrace_hash_empty(hash->notrace_hash) ||
1455 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1459 * Test the hashes for this ops to see if we want to call
1460 * the ops->func or not.
1462 * It's a match if the ip is in the ops->filter_hash or
1463 * the filter_hash does not exist or is empty,
1465 * the ip is not in the ops->notrace_hash.
1467 * This needs to be called with preemption disabled as
1468 * the hashes are freed with call_rcu().
1471 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1473 struct ftrace_ops_hash hash;
1476 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1478 * There's a small race when adding ops that the ftrace handler
1479 * that wants regs, may be called without them. We can not
1480 * allow that handler to be called if regs is NULL.
1482 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1486 rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1487 rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1489 if (hash_contains_ip(ip, &hash))
1498 * This is a double for. Do not use 'break' to break out of the loop,
1499 * you must use a goto.
1501 #define do_for_each_ftrace_rec(pg, rec) \
1502 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1504 for (_____i = 0; _____i < pg->index; _____i++) { \
1505 rec = &pg->records[_____i];
1507 #define while_for_each_ftrace_rec() \
1512 static int ftrace_cmp_recs(const void *a, const void *b)
1514 const struct dyn_ftrace *key = a;
1515 const struct dyn_ftrace *rec = b;
1517 if (key->flags < rec->ip)
1519 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1524 static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
1526 struct ftrace_page *pg;
1527 struct dyn_ftrace *rec = NULL;
1528 struct dyn_ftrace key;
1531 key.flags = end; /* overload flags, as it is unsigned long */
1533 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1534 if (end < pg->records[0].ip ||
1535 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1537 rec = bsearch(&key, pg->records, pg->index,
1538 sizeof(struct dyn_ftrace),
1547 * ftrace_location_range - return the first address of a traced location
1548 * if it touches the given ip range
1549 * @start: start of range to search.
1550 * @end: end of range to search (inclusive). @end points to the last byte
1553 * Returns rec->ip if the related ftrace location is a least partly within
1554 * the given address range. That is, the first address of the instruction
1555 * that is either a NOP or call to the function tracer. It checks the ftrace
1556 * internal tables to determine if the address belongs or not.
1558 unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1560 struct dyn_ftrace *rec;
1562 rec = lookup_rec(start, end);
1570 * ftrace_location - return the ftrace location
1571 * @ip: the instruction pointer to check
1573 * If @ip matches the ftrace location, return @ip.
1574 * If @ip matches sym+0, return sym's ftrace location.
1575 * Otherwise, return 0.
1577 unsigned long ftrace_location(unsigned long ip)
1579 struct dyn_ftrace *rec;
1580 unsigned long offset;
1583 rec = lookup_rec(ip, ip);
1585 if (!kallsyms_lookup_size_offset(ip, &size, &offset))
1588 /* map sym+0 to __fentry__ */
1590 rec = lookup_rec(ip, ip + size - 1);
1601 * ftrace_text_reserved - return true if range contains an ftrace location
1602 * @start: start of range to search
1603 * @end: end of range to search (inclusive). @end points to the last byte to check.
1605 * Returns 1 if @start and @end contains a ftrace location.
1606 * That is, the instruction that is either a NOP or call to
1607 * the function tracer. It checks the ftrace internal tables to
1608 * determine if the address belongs or not.
1610 int ftrace_text_reserved(const void *start, const void *end)
1614 ret = ftrace_location_range((unsigned long)start,
1615 (unsigned long)end);
1620 /* Test if ops registered to this rec needs regs */
1621 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1623 struct ftrace_ops *ops;
1624 bool keep_regs = false;
1626 for (ops = ftrace_ops_list;
1627 ops != &ftrace_list_end; ops = ops->next) {
1628 /* pass rec in as regs to have non-NULL val */
1629 if (ftrace_ops_test(ops, rec->ip, rec)) {
1630 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1640 static struct ftrace_ops *
1641 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1642 static struct ftrace_ops *
1643 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude);
1644 static struct ftrace_ops *
1645 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1647 static bool skip_record(struct dyn_ftrace *rec)
1650 * At boot up, weak functions are set to disable. Function tracing
1651 * can be enabled before they are, and they still need to be disabled now.
1652 * If the record is disabled, still continue if it is marked as already
1653 * enabled (this is needed to keep the accounting working).
1655 return rec->flags & FTRACE_FL_DISABLED &&
1656 !(rec->flags & FTRACE_FL_ENABLED);
1659 static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1663 struct ftrace_hash *hash;
1664 struct ftrace_hash *other_hash;
1665 struct ftrace_page *pg;
1666 struct dyn_ftrace *rec;
1667 bool update = false;
1671 /* Only update if the ops has been registered */
1672 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1676 * In the filter_hash case:
1677 * If the count is zero, we update all records.
1678 * Otherwise we just update the items in the hash.
1680 * In the notrace_hash case:
1681 * We enable the update in the hash.
1682 * As disabling notrace means enabling the tracing,
1683 * and enabling notrace means disabling, the inc variable
1687 hash = ops->func_hash->filter_hash;
1688 other_hash = ops->func_hash->notrace_hash;
1689 if (ftrace_hash_empty(hash))
1693 hash = ops->func_hash->notrace_hash;
1694 other_hash = ops->func_hash->filter_hash;
1696 * If the notrace hash has no items,
1697 * then there's nothing to do.
1699 if (ftrace_hash_empty(hash))
1703 do_for_each_ftrace_rec(pg, rec) {
1704 int in_other_hash = 0;
1708 if (skip_record(rec))
1713 * Only the filter_hash affects all records.
1714 * Update if the record is not in the notrace hash.
1716 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1719 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1720 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1723 * If filter_hash is set, we want to match all functions
1724 * that are in the hash but not in the other hash.
1726 * If filter_hash is not set, then we are decrementing.
1727 * That means we match anything that is in the hash
1728 * and also in the other_hash. That is, we need to turn
1729 * off functions in the other hash because they are disabled
1732 if (filter_hash && in_hash && !in_other_hash)
1734 else if (!filter_hash && in_hash &&
1735 (in_other_hash || ftrace_hash_empty(other_hash)))
1743 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1746 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1747 rec->flags |= FTRACE_FL_DIRECT;
1750 * If there's only a single callback registered to a
1751 * function, and the ops has a trampoline registered
1752 * for it, then we can call it directly.
1754 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1755 rec->flags |= FTRACE_FL_TRAMP;
1758 * If we are adding another function callback
1759 * to this function, and the previous had a
1760 * custom trampoline in use, then we need to go
1761 * back to the default trampoline.
1763 rec->flags &= ~FTRACE_FL_TRAMP;
1766 * If any ops wants regs saved for this function
1767 * then all ops will get saved regs.
1769 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1770 rec->flags |= FTRACE_FL_REGS;
1772 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1777 * Only the internal direct_ops should have the
1778 * DIRECT flag set. Thus, if it is removing a
1779 * function, then that function should no longer
1782 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1783 rec->flags &= ~FTRACE_FL_DIRECT;
1786 * If the rec had REGS enabled and the ops that is
1787 * being removed had REGS set, then see if there is
1788 * still any ops for this record that wants regs.
1789 * If not, we can stop recording them.
1791 if (ftrace_rec_count(rec) > 0 &&
1792 rec->flags & FTRACE_FL_REGS &&
1793 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1794 if (!test_rec_ops_needs_regs(rec))
1795 rec->flags &= ~FTRACE_FL_REGS;
1799 * The TRAMP needs to be set only if rec count
1800 * is decremented to one, and the ops that is
1801 * left has a trampoline. As TRAMP can only be
1802 * enabled if there is only a single ops attached
1805 if (ftrace_rec_count(rec) == 1 &&
1806 ftrace_find_tramp_ops_any_other(rec, ops))
1807 rec->flags |= FTRACE_FL_TRAMP;
1809 rec->flags &= ~FTRACE_FL_TRAMP;
1812 * flags will be cleared in ftrace_check_record()
1813 * if rec count is zero.
1818 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1819 update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1821 /* Shortcut, if we handled all records, we are done. */
1822 if (!all && count == hash->count)
1824 } while_for_each_ftrace_rec();
1829 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1832 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1835 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1838 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1841 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1842 int filter_hash, int inc)
1844 struct ftrace_ops *op;
1846 __ftrace_hash_rec_update(ops, filter_hash, inc);
1848 if (ops->func_hash != &global_ops.local_hash)
1852 * If the ops shares the global_ops hash, then we need to update
1853 * all ops that are enabled and use this hash.
1855 do_for_each_ftrace_op(op, ftrace_ops_list) {
1859 if (op->func_hash == &global_ops.local_hash)
1860 __ftrace_hash_rec_update(op, filter_hash, inc);
1861 } while_for_each_ftrace_op(op);
1864 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1867 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1870 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1873 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1877 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1878 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1879 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1880 * Note that old_hash and new_hash has below meanings
1881 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1882 * - If the hash is EMPTY_HASH, it hits nothing
1883 * - Anything else hits the recs which match the hash entries.
1885 * DIRECT ops does not have IPMODIFY flag, but we still need to check it
1886 * against functions with FTRACE_FL_IPMODIFY. If there is any overlap, call
1887 * ops_func(SHARE_IPMODIFY_SELF) to make sure current ops can share with
1888 * IPMODIFY. If ops_func(SHARE_IPMODIFY_SELF) returns non-zero, propagate
1889 * the return value to the caller and eventually to the owner of the DIRECT
1892 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1893 struct ftrace_hash *old_hash,
1894 struct ftrace_hash *new_hash)
1896 struct ftrace_page *pg;
1897 struct dyn_ftrace *rec, *end = NULL;
1899 bool is_ipmodify, is_direct;
1901 /* Only update if the ops has been registered */
1902 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1905 is_ipmodify = ops->flags & FTRACE_OPS_FL_IPMODIFY;
1906 is_direct = ops->flags & FTRACE_OPS_FL_DIRECT;
1908 /* neither IPMODIFY nor DIRECT, skip */
1909 if (!is_ipmodify && !is_direct)
1912 if (WARN_ON_ONCE(is_ipmodify && is_direct))
1916 * Since the IPMODIFY and DIRECT are very address sensitive
1917 * actions, we do not allow ftrace_ops to set all functions to new
1920 if (!new_hash || !old_hash)
1923 /* Update rec->flags */
1924 do_for_each_ftrace_rec(pg, rec) {
1926 if (rec->flags & FTRACE_FL_DISABLED)
1929 /* We need to update only differences of filter_hash */
1930 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1931 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1932 if (in_old == in_new)
1936 if (rec->flags & FTRACE_FL_IPMODIFY) {
1939 /* Cannot have two ipmodify on same rec */
1943 FTRACE_WARN_ON(rec->flags & FTRACE_FL_DIRECT);
1946 * Another ops with IPMODIFY is already
1947 * attached. We are now attaching a direct
1948 * ops. Run SHARE_IPMODIFY_SELF, to check
1949 * whether sharing is supported.
1953 ret = ops->ops_func(ops, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF);
1956 } else if (is_ipmodify) {
1957 rec->flags |= FTRACE_FL_IPMODIFY;
1959 } else if (is_ipmodify) {
1960 rec->flags &= ~FTRACE_FL_IPMODIFY;
1962 } while_for_each_ftrace_rec();
1969 /* Roll back what we did above */
1970 do_for_each_ftrace_rec(pg, rec) {
1972 if (rec->flags & FTRACE_FL_DISABLED)
1978 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1979 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1980 if (in_old == in_new)
1984 rec->flags &= ~FTRACE_FL_IPMODIFY;
1986 rec->flags |= FTRACE_FL_IPMODIFY;
1987 } while_for_each_ftrace_rec();
1993 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1995 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1997 if (ftrace_hash_empty(hash))
2000 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
2003 /* Disabling always succeeds */
2004 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
2006 struct ftrace_hash *hash = ops->func_hash->filter_hash;
2008 if (ftrace_hash_empty(hash))
2011 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
2014 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
2015 struct ftrace_hash *new_hash)
2017 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
2019 if (ftrace_hash_empty(old_hash))
2022 if (ftrace_hash_empty(new_hash))
2025 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
2028 static void print_ip_ins(const char *fmt, const unsigned char *p)
2030 char ins[MCOUNT_INSN_SIZE];
2032 if (copy_from_kernel_nofault(ins, p, MCOUNT_INSN_SIZE)) {
2033 printk(KERN_CONT "%s[FAULT] %px\n", fmt, p);
2037 printk(KERN_CONT "%s", fmt);
2038 pr_cont("%*phC", MCOUNT_INSN_SIZE, ins);
2041 enum ftrace_bug_type ftrace_bug_type;
2042 const void *ftrace_expected;
2044 static void print_bug_type(void)
2046 switch (ftrace_bug_type) {
2047 case FTRACE_BUG_UNKNOWN:
2049 case FTRACE_BUG_INIT:
2050 pr_info("Initializing ftrace call sites\n");
2052 case FTRACE_BUG_NOP:
2053 pr_info("Setting ftrace call site to NOP\n");
2055 case FTRACE_BUG_CALL:
2056 pr_info("Setting ftrace call site to call ftrace function\n");
2058 case FTRACE_BUG_UPDATE:
2059 pr_info("Updating ftrace call site to call a different ftrace function\n");
2065 * ftrace_bug - report and shutdown function tracer
2066 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2067 * @rec: The record that failed
2069 * The arch code that enables or disables the function tracing
2070 * can call ftrace_bug() when it has detected a problem in
2071 * modifying the code. @failed should be one of either:
2072 * EFAULT - if the problem happens on reading the @ip address
2073 * EINVAL - if what is read at @ip is not what was expected
2074 * EPERM - if the problem happens on writing to the @ip address
2076 void ftrace_bug(int failed, struct dyn_ftrace *rec)
2078 unsigned long ip = rec ? rec->ip : 0;
2080 pr_info("------------[ ftrace bug ]------------\n");
2084 pr_info("ftrace faulted on modifying ");
2085 print_ip_sym(KERN_INFO, ip);
2088 pr_info("ftrace failed to modify ");
2089 print_ip_sym(KERN_INFO, ip);
2090 print_ip_ins(" actual: ", (unsigned char *)ip);
2092 if (ftrace_expected) {
2093 print_ip_ins(" expected: ", ftrace_expected);
2098 pr_info("ftrace faulted on writing ");
2099 print_ip_sym(KERN_INFO, ip);
2102 pr_info("ftrace faulted on unknown error ");
2103 print_ip_sym(KERN_INFO, ip);
2107 struct ftrace_ops *ops = NULL;
2109 pr_info("ftrace record flags: %lx\n", rec->flags);
2110 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2111 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2112 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2113 ops = ftrace_find_tramp_ops_any(rec);
2116 pr_cont("\ttramp: %pS (%pS)",
2117 (void *)ops->trampoline,
2119 ops = ftrace_find_tramp_ops_next(rec, ops);
2122 pr_cont("\ttramp: ERROR!");
2125 ip = ftrace_get_addr_curr(rec);
2126 pr_cont("\n expected tramp: %lx\n", ip);
2129 FTRACE_WARN_ON_ONCE(1);
2132 static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2134 unsigned long flag = 0UL;
2136 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2138 if (skip_record(rec))
2139 return FTRACE_UPDATE_IGNORE;
2142 * If we are updating calls:
2144 * If the record has a ref count, then we need to enable it
2145 * because someone is using it.
2147 * Otherwise we make sure its disabled.
2149 * If we are disabling calls, then disable all records that
2152 if (enable && ftrace_rec_count(rec))
2153 flag = FTRACE_FL_ENABLED;
2156 * If enabling and the REGS flag does not match the REGS_EN, or
2157 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2158 * this record. Set flags to fail the compare against ENABLED.
2159 * Same for direct calls.
2162 if (!(rec->flags & FTRACE_FL_REGS) !=
2163 !(rec->flags & FTRACE_FL_REGS_EN))
2164 flag |= FTRACE_FL_REGS;
2166 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2167 !(rec->flags & FTRACE_FL_TRAMP_EN))
2168 flag |= FTRACE_FL_TRAMP;
2171 * Direct calls are special, as count matters.
2172 * We must test the record for direct, if the
2173 * DIRECT and DIRECT_EN do not match, but only
2174 * if the count is 1. That's because, if the
2175 * count is something other than one, we do not
2176 * want the direct enabled (it will be done via the
2177 * direct helper). But if DIRECT_EN is set, and
2178 * the count is not one, we need to clear it.
2180 if (ftrace_rec_count(rec) == 1) {
2181 if (!(rec->flags & FTRACE_FL_DIRECT) !=
2182 !(rec->flags & FTRACE_FL_DIRECT_EN))
2183 flag |= FTRACE_FL_DIRECT;
2184 } else if (rec->flags & FTRACE_FL_DIRECT_EN) {
2185 flag |= FTRACE_FL_DIRECT;
2189 /* If the state of this record hasn't changed, then do nothing */
2190 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2191 return FTRACE_UPDATE_IGNORE;
2194 /* Save off if rec is being enabled (for return value) */
2195 flag ^= rec->flags & FTRACE_FL_ENABLED;
2198 rec->flags |= FTRACE_FL_ENABLED;
2199 if (flag & FTRACE_FL_REGS) {
2200 if (rec->flags & FTRACE_FL_REGS)
2201 rec->flags |= FTRACE_FL_REGS_EN;
2203 rec->flags &= ~FTRACE_FL_REGS_EN;
2205 if (flag & FTRACE_FL_TRAMP) {
2206 if (rec->flags & FTRACE_FL_TRAMP)
2207 rec->flags |= FTRACE_FL_TRAMP_EN;
2209 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2212 if (flag & FTRACE_FL_DIRECT) {
2214 * If there's only one user (direct_ops helper)
2215 * then we can call the direct function
2216 * directly (no ftrace trampoline).
2218 if (ftrace_rec_count(rec) == 1) {
2219 if (rec->flags & FTRACE_FL_DIRECT)
2220 rec->flags |= FTRACE_FL_DIRECT_EN;
2222 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2225 * Can only call directly if there's
2226 * only one callback to the function.
2228 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2234 * If this record is being updated from a nop, then
2235 * return UPDATE_MAKE_CALL.
2237 * return UPDATE_MODIFY_CALL to tell the caller to convert
2238 * from the save regs, to a non-save regs function or
2239 * vice versa, or from a trampoline call.
2241 if (flag & FTRACE_FL_ENABLED) {
2242 ftrace_bug_type = FTRACE_BUG_CALL;
2243 return FTRACE_UPDATE_MAKE_CALL;
2246 ftrace_bug_type = FTRACE_BUG_UPDATE;
2247 return FTRACE_UPDATE_MODIFY_CALL;
2251 /* If there's no more users, clear all flags */
2252 if (!ftrace_rec_count(rec))
2253 rec->flags &= FTRACE_FL_DISABLED;
2256 * Just disable the record, but keep the ops TRAMP
2257 * and REGS states. The _EN flags must be disabled though.
2259 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2260 FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN);
2263 ftrace_bug_type = FTRACE_BUG_NOP;
2264 return FTRACE_UPDATE_MAKE_NOP;
2268 * ftrace_update_record - set a record that now is tracing or not
2269 * @rec: the record to update
2270 * @enable: set to true if the record is tracing, false to force disable
2272 * The records that represent all functions that can be traced need
2273 * to be updated when tracing has been enabled.
2275 int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2277 return ftrace_check_record(rec, enable, true);
2281 * ftrace_test_record - check if the record has been enabled or not
2282 * @rec: the record to test
2283 * @enable: set to true to check if enabled, false if it is disabled
2285 * The arch code may need to test if a record is already set to
2286 * tracing to determine how to modify the function code that it
2289 int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2291 return ftrace_check_record(rec, enable, false);
2294 static struct ftrace_ops *
2295 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2297 struct ftrace_ops *op;
2298 unsigned long ip = rec->ip;
2300 do_for_each_ftrace_op(op, ftrace_ops_list) {
2302 if (!op->trampoline)
2305 if (hash_contains_ip(ip, op->func_hash))
2307 } while_for_each_ftrace_op(op);
2312 static struct ftrace_ops *
2313 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude)
2315 struct ftrace_ops *op;
2316 unsigned long ip = rec->ip;
2318 do_for_each_ftrace_op(op, ftrace_ops_list) {
2320 if (op == op_exclude || !op->trampoline)
2323 if (hash_contains_ip(ip, op->func_hash))
2325 } while_for_each_ftrace_op(op);
2330 static struct ftrace_ops *
2331 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2332 struct ftrace_ops *op)
2334 unsigned long ip = rec->ip;
2336 while_for_each_ftrace_op(op) {
2338 if (!op->trampoline)
2341 if (hash_contains_ip(ip, op->func_hash))
2348 static struct ftrace_ops *
2349 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2351 struct ftrace_ops *op;
2352 unsigned long ip = rec->ip;
2355 * Need to check removed ops first.
2356 * If they are being removed, and this rec has a tramp,
2357 * and this rec is in the ops list, then it would be the
2358 * one with the tramp.
2361 if (hash_contains_ip(ip, &removed_ops->old_hash))
2366 * Need to find the current trampoline for a rec.
2367 * Now, a trampoline is only attached to a rec if there
2368 * was a single 'ops' attached to it. But this can be called
2369 * when we are adding another op to the rec or removing the
2370 * current one. Thus, if the op is being added, we can
2371 * ignore it because it hasn't attached itself to the rec
2374 * If an ops is being modified (hooking to different functions)
2375 * then we don't care about the new functions that are being
2376 * added, just the old ones (that are probably being removed).
2378 * If we are adding an ops to a function that already is using
2379 * a trampoline, it needs to be removed (trampolines are only
2380 * for single ops connected), then an ops that is not being
2381 * modified also needs to be checked.
2383 do_for_each_ftrace_op(op, ftrace_ops_list) {
2385 if (!op->trampoline)
2389 * If the ops is being added, it hasn't gotten to
2390 * the point to be removed from this tree yet.
2392 if (op->flags & FTRACE_OPS_FL_ADDING)
2397 * If the ops is being modified and is in the old
2398 * hash, then it is probably being removed from this
2401 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2402 hash_contains_ip(ip, &op->old_hash))
2405 * If the ops is not being added or modified, and it's
2406 * in its normal filter hash, then this must be the one
2409 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2410 hash_contains_ip(ip, op->func_hash))
2413 } while_for_each_ftrace_op(op);
2418 static struct ftrace_ops *
2419 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2421 struct ftrace_ops *op;
2422 unsigned long ip = rec->ip;
2424 do_for_each_ftrace_op(op, ftrace_ops_list) {
2425 /* pass rec in as regs to have non-NULL val */
2426 if (hash_contains_ip(ip, op->func_hash))
2428 } while_for_each_ftrace_op(op);
2433 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
2434 /* Protected by rcu_tasks for reading, and direct_mutex for writing */
2435 static struct ftrace_hash *direct_functions = EMPTY_HASH;
2436 static DEFINE_MUTEX(direct_mutex);
2437 int ftrace_direct_func_count;
2440 * Search the direct_functions hash to see if the given instruction pointer
2441 * has a direct caller attached to it.
2443 unsigned long ftrace_find_rec_direct(unsigned long ip)
2445 struct ftrace_func_entry *entry;
2447 entry = __ftrace_lookup_ip(direct_functions, ip);
2451 return entry->direct;
2454 static struct ftrace_func_entry*
2455 ftrace_add_rec_direct(unsigned long ip, unsigned long addr,
2456 struct ftrace_hash **free_hash)
2458 struct ftrace_func_entry *entry;
2460 if (ftrace_hash_empty(direct_functions) ||
2461 direct_functions->count > 2 * (1 << direct_functions->size_bits)) {
2462 struct ftrace_hash *new_hash;
2463 int size = ftrace_hash_empty(direct_functions) ? 0 :
2464 direct_functions->count + 1;
2469 new_hash = dup_hash(direct_functions, size);
2473 *free_hash = direct_functions;
2474 direct_functions = new_hash;
2477 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2482 entry->direct = addr;
2483 __add_hash_entry(direct_functions, entry);
2487 static void call_direct_funcs(unsigned long ip, unsigned long pip,
2488 struct ftrace_ops *ops, struct ftrace_regs *fregs)
2490 struct pt_regs *regs = ftrace_get_regs(fregs);
2493 addr = ftrace_find_rec_direct(ip);
2497 arch_ftrace_set_direct_caller(regs, addr);
2500 struct ftrace_ops direct_ops = {
2501 .func = call_direct_funcs,
2502 .flags = FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
2503 | FTRACE_OPS_FL_PERMANENT,
2505 * By declaring the main trampoline as this trampoline
2506 * it will never have one allocated for it. Allocated
2507 * trampolines should not call direct functions.
2508 * The direct_ops should only be called by the builtin
2509 * ftrace_regs_caller trampoline.
2511 .trampoline = FTRACE_REGS_ADDR,
2513 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
2516 * ftrace_get_addr_new - Get the call address to set to
2517 * @rec: The ftrace record descriptor
2519 * If the record has the FTRACE_FL_REGS set, that means that it
2520 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2521 * is not set, then it wants to convert to the normal callback.
2523 * Returns the address of the trampoline to set to
2525 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2527 struct ftrace_ops *ops;
2530 if ((rec->flags & FTRACE_FL_DIRECT) &&
2531 (ftrace_rec_count(rec) == 1)) {
2532 addr = ftrace_find_rec_direct(rec->ip);
2538 /* Trampolines take precedence over regs */
2539 if (rec->flags & FTRACE_FL_TRAMP) {
2540 ops = ftrace_find_tramp_ops_new(rec);
2541 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2542 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2543 (void *)rec->ip, (void *)rec->ip, rec->flags);
2544 /* Ftrace is shutting down, return anything */
2545 return (unsigned long)FTRACE_ADDR;
2547 return ops->trampoline;
2550 if (rec->flags & FTRACE_FL_REGS)
2551 return (unsigned long)FTRACE_REGS_ADDR;
2553 return (unsigned long)FTRACE_ADDR;
2557 * ftrace_get_addr_curr - Get the call address that is already there
2558 * @rec: The ftrace record descriptor
2560 * The FTRACE_FL_REGS_EN is set when the record already points to
2561 * a function that saves all the regs. Basically the '_EN' version
2562 * represents the current state of the function.
2564 * Returns the address of the trampoline that is currently being called
2566 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2568 struct ftrace_ops *ops;
2571 /* Direct calls take precedence over trampolines */
2572 if (rec->flags & FTRACE_FL_DIRECT_EN) {
2573 addr = ftrace_find_rec_direct(rec->ip);
2579 /* Trampolines take precedence over regs */
2580 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2581 ops = ftrace_find_tramp_ops_curr(rec);
2582 if (FTRACE_WARN_ON(!ops)) {
2583 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2584 (void *)rec->ip, (void *)rec->ip);
2585 /* Ftrace is shutting down, return anything */
2586 return (unsigned long)FTRACE_ADDR;
2588 return ops->trampoline;
2591 if (rec->flags & FTRACE_FL_REGS_EN)
2592 return (unsigned long)FTRACE_REGS_ADDR;
2594 return (unsigned long)FTRACE_ADDR;
2598 __ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2600 unsigned long ftrace_old_addr;
2601 unsigned long ftrace_addr;
2604 ftrace_addr = ftrace_get_addr_new(rec);
2606 /* This needs to be done before we call ftrace_update_record */
2607 ftrace_old_addr = ftrace_get_addr_curr(rec);
2609 ret = ftrace_update_record(rec, enable);
2611 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2614 case FTRACE_UPDATE_IGNORE:
2617 case FTRACE_UPDATE_MAKE_CALL:
2618 ftrace_bug_type = FTRACE_BUG_CALL;
2619 return ftrace_make_call(rec, ftrace_addr);
2621 case FTRACE_UPDATE_MAKE_NOP:
2622 ftrace_bug_type = FTRACE_BUG_NOP;
2623 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2625 case FTRACE_UPDATE_MODIFY_CALL:
2626 ftrace_bug_type = FTRACE_BUG_UPDATE;
2627 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2630 return -1; /* unknown ftrace bug */
2633 void __weak ftrace_replace_code(int mod_flags)
2635 struct dyn_ftrace *rec;
2636 struct ftrace_page *pg;
2637 bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2638 int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2641 if (unlikely(ftrace_disabled))
2644 do_for_each_ftrace_rec(pg, rec) {
2646 if (skip_record(rec))
2649 failed = __ftrace_replace_code(rec, enable);
2651 ftrace_bug(failed, rec);
2652 /* Stop processing */
2657 } while_for_each_ftrace_rec();
2660 struct ftrace_rec_iter {
2661 struct ftrace_page *pg;
2666 * ftrace_rec_iter_start - start up iterating over traced functions
2668 * Returns an iterator handle that is used to iterate over all
2669 * the records that represent address locations where functions
2672 * May return NULL if no records are available.
2674 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2677 * We only use a single iterator.
2678 * Protected by the ftrace_lock mutex.
2680 static struct ftrace_rec_iter ftrace_rec_iter;
2681 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2683 iter->pg = ftrace_pages_start;
2686 /* Could have empty pages */
2687 while (iter->pg && !iter->pg->index)
2688 iter->pg = iter->pg->next;
2697 * ftrace_rec_iter_next - get the next record to process.
2698 * @iter: The handle to the iterator.
2700 * Returns the next iterator after the given iterator @iter.
2702 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2706 if (iter->index >= iter->pg->index) {
2707 iter->pg = iter->pg->next;
2710 /* Could have empty pages */
2711 while (iter->pg && !iter->pg->index)
2712 iter->pg = iter->pg->next;
2722 * ftrace_rec_iter_record - get the record at the iterator location
2723 * @iter: The current iterator location
2725 * Returns the record that the current @iter is at.
2727 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2729 return &iter->pg->records[iter->index];
2733 ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
2737 if (unlikely(ftrace_disabled))
2740 ret = ftrace_init_nop(mod, rec);
2742 ftrace_bug_type = FTRACE_BUG_INIT;
2743 ftrace_bug(ret, rec);
2750 * archs can override this function if they must do something
2751 * before the modifying code is performed.
2753 void __weak ftrace_arch_code_modify_prepare(void)
2758 * archs can override this function if they must do something
2759 * after the modifying code is performed.
2761 void __weak ftrace_arch_code_modify_post_process(void)
2765 void ftrace_modify_all_code(int command)
2767 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2771 if (command & FTRACE_MAY_SLEEP)
2772 mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2775 * If the ftrace_caller calls a ftrace_ops func directly,
2776 * we need to make sure that it only traces functions it
2777 * expects to trace. When doing the switch of functions,
2778 * we need to update to the ftrace_ops_list_func first
2779 * before the transition between old and new calls are set,
2780 * as the ftrace_ops_list_func will check the ops hashes
2781 * to make sure the ops are having the right functions
2785 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2786 if (FTRACE_WARN_ON(err))
2790 if (command & FTRACE_UPDATE_CALLS)
2791 ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2792 else if (command & FTRACE_DISABLE_CALLS)
2793 ftrace_replace_code(mod_flags);
2795 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2796 function_trace_op = set_function_trace_op;
2798 /* If irqs are disabled, we are in stop machine */
2799 if (!irqs_disabled())
2800 smp_call_function(ftrace_sync_ipi, NULL, 1);
2801 err = ftrace_update_ftrace_func(ftrace_trace_function);
2802 if (FTRACE_WARN_ON(err))
2806 if (command & FTRACE_START_FUNC_RET)
2807 err = ftrace_enable_ftrace_graph_caller();
2808 else if (command & FTRACE_STOP_FUNC_RET)
2809 err = ftrace_disable_ftrace_graph_caller();
2810 FTRACE_WARN_ON(err);
2813 static int __ftrace_modify_code(void *data)
2815 int *command = data;
2817 ftrace_modify_all_code(*command);
2823 * ftrace_run_stop_machine - go back to the stop machine method
2824 * @command: The command to tell ftrace what to do
2826 * If an arch needs to fall back to the stop machine method, the
2827 * it can call this function.
2829 void ftrace_run_stop_machine(int command)
2831 stop_machine(__ftrace_modify_code, &command, NULL);
2835 * arch_ftrace_update_code - modify the code to trace or not trace
2836 * @command: The command that needs to be done
2838 * Archs can override this function if it does not need to
2839 * run stop_machine() to modify code.
2841 void __weak arch_ftrace_update_code(int command)
2843 ftrace_run_stop_machine(command);
2846 static void ftrace_run_update_code(int command)
2848 ftrace_arch_code_modify_prepare();
2851 * By default we use stop_machine() to modify the code.
2852 * But archs can do what ever they want as long as it
2853 * is safe. The stop_machine() is the safest, but also
2854 * produces the most overhead.
2856 arch_ftrace_update_code(command);
2858 ftrace_arch_code_modify_post_process();
2861 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2862 struct ftrace_ops_hash *old_hash)
2864 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2865 ops->old_hash.filter_hash = old_hash->filter_hash;
2866 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2867 ftrace_run_update_code(command);
2868 ops->old_hash.filter_hash = NULL;
2869 ops->old_hash.notrace_hash = NULL;
2870 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2873 static ftrace_func_t saved_ftrace_func;
2874 static int ftrace_start_up;
2876 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2880 /* List of trace_ops that have allocated trampolines */
2881 static LIST_HEAD(ftrace_ops_trampoline_list);
2883 static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops *ops)
2885 lockdep_assert_held(&ftrace_lock);
2886 list_add_rcu(&ops->list, &ftrace_ops_trampoline_list);
2889 static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops)
2891 lockdep_assert_held(&ftrace_lock);
2892 list_del_rcu(&ops->list);
2897 * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols
2898 * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is
2901 #define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace"
2902 #define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"
2904 static void ftrace_trampoline_free(struct ftrace_ops *ops)
2906 if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
2909 * Record the text poke event before the ksymbol unregister
2912 perf_event_text_poke((void *)ops->trampoline,
2913 (void *)ops->trampoline,
2914 ops->trampoline_size, NULL, 0);
2915 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
2916 ops->trampoline, ops->trampoline_size,
2917 true, FTRACE_TRAMPOLINE_SYM);
2918 /* Remove from kallsyms after the perf events */
2919 ftrace_remove_trampoline_from_kallsyms(ops);
2922 arch_ftrace_trampoline_free(ops);
2925 static void ftrace_startup_enable(int command)
2927 if (saved_ftrace_func != ftrace_trace_function) {
2928 saved_ftrace_func = ftrace_trace_function;
2929 command |= FTRACE_UPDATE_TRACE_FUNC;
2932 if (!command || !ftrace_enabled)
2935 ftrace_run_update_code(command);
2938 static void ftrace_startup_all(int command)
2940 update_all_ops = true;
2941 ftrace_startup_enable(command);
2942 update_all_ops = false;
2945 int ftrace_startup(struct ftrace_ops *ops, int command)
2949 if (unlikely(ftrace_disabled))
2952 ret = __register_ftrace_function(ops);
2959 * Note that ftrace probes uses this to start up
2960 * and modify functions it will probe. But we still
2961 * set the ADDING flag for modification, as probes
2962 * do not have trampolines. If they add them in the
2963 * future, then the probes will need to distinguish
2964 * between adding and updating probes.
2966 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2968 ret = ftrace_hash_ipmodify_enable(ops);
2970 /* Rollback registration process */
2971 __unregister_ftrace_function(ops);
2973 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2974 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2975 ftrace_trampoline_free(ops);
2979 if (ftrace_hash_rec_enable(ops, 1))
2980 command |= FTRACE_UPDATE_CALLS;
2982 ftrace_startup_enable(command);
2985 * If ftrace is in an undefined state, we just remove ops from list
2986 * to prevent the NULL pointer, instead of totally rolling it back and
2987 * free trampoline, because those actions could cause further damage.
2989 if (unlikely(ftrace_disabled)) {
2990 __unregister_ftrace_function(ops);
2994 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2999 int ftrace_shutdown(struct ftrace_ops *ops, int command)
3003 if (unlikely(ftrace_disabled))
3006 ret = __unregister_ftrace_function(ops);
3012 * Just warn in case of unbalance, no need to kill ftrace, it's not
3013 * critical but the ftrace_call callers may be never nopped again after
3014 * further ftrace uses.
3016 WARN_ON_ONCE(ftrace_start_up < 0);
3018 /* Disabling ipmodify never fails */
3019 ftrace_hash_ipmodify_disable(ops);
3021 if (ftrace_hash_rec_disable(ops, 1))
3022 command |= FTRACE_UPDATE_CALLS;
3024 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
3026 if (saved_ftrace_func != ftrace_trace_function) {
3027 saved_ftrace_func = ftrace_trace_function;
3028 command |= FTRACE_UPDATE_TRACE_FUNC;
3031 if (!command || !ftrace_enabled)
3035 * If the ops uses a trampoline, then it needs to be
3036 * tested first on update.
3038 ops->flags |= FTRACE_OPS_FL_REMOVING;
3041 /* The trampoline logic checks the old hashes */
3042 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
3043 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
3045 ftrace_run_update_code(command);
3048 * If there's no more ops registered with ftrace, run a
3049 * sanity check to make sure all rec flags are cleared.
3051 if (rcu_dereference_protected(ftrace_ops_list,
3052 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
3053 struct ftrace_page *pg;
3054 struct dyn_ftrace *rec;
3056 do_for_each_ftrace_rec(pg, rec) {
3057 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
3058 pr_warn(" %pS flags:%lx\n",
3059 (void *)rec->ip, rec->flags);
3060 } while_for_each_ftrace_rec();
3063 ops->old_hash.filter_hash = NULL;
3064 ops->old_hash.notrace_hash = NULL;
3067 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
3071 * Dynamic ops may be freed, we must make sure that all
3072 * callers are done before leaving this function.
3073 * The same goes for freeing the per_cpu data of the per_cpu
3076 if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
3078 * We need to do a hard force of sched synchronization.
3079 * This is because we use preempt_disable() to do RCU, but
3080 * the function tracers can be called where RCU is not watching
3081 * (like before user_exit()). We can not rely on the RCU
3082 * infrastructure to do the synchronization, thus we must do it
3085 synchronize_rcu_tasks_rude();
3088 * When the kernel is preemptive, tasks can be preempted
3089 * while on a ftrace trampoline. Just scheduling a task on
3090 * a CPU is not good enough to flush them. Calling
3091 * synchronize_rcu_tasks() will wait for those tasks to
3092 * execute and either schedule voluntarily or enter user space.
3094 if (IS_ENABLED(CONFIG_PREEMPTION))
3095 synchronize_rcu_tasks();
3097 ftrace_trampoline_free(ops);
3103 static u64 ftrace_update_time;
3104 unsigned long ftrace_update_tot_cnt;
3105 unsigned long ftrace_number_of_pages;
3106 unsigned long ftrace_number_of_groups;
3108 static inline int ops_traces_mod(struct ftrace_ops *ops)
3111 * Filter_hash being empty will default to trace module.
3112 * But notrace hash requires a test of individual module functions.
3114 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
3115 ftrace_hash_empty(ops->func_hash->notrace_hash);
3118 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
3120 bool init_nop = ftrace_need_init_nop();
3121 struct ftrace_page *pg;
3122 struct dyn_ftrace *p;
3124 unsigned long update_cnt = 0;
3125 unsigned long rec_flags = 0;
3128 start = ftrace_now(raw_smp_processor_id());
3131 * When a module is loaded, this function is called to convert
3132 * the calls to mcount in its text to nops, and also to create
3133 * an entry in the ftrace data. Now, if ftrace is activated
3134 * after this call, but before the module sets its text to
3135 * read-only, the modification of enabling ftrace can fail if
3136 * the read-only is done while ftrace is converting the calls.
3137 * To prevent this, the module's records are set as disabled
3138 * and will be enabled after the call to set the module's text
3142 rec_flags |= FTRACE_FL_DISABLED;
3144 for (pg = new_pgs; pg; pg = pg->next) {
3146 for (i = 0; i < pg->index; i++) {
3148 /* If something went wrong, bail without enabling anything */
3149 if (unlikely(ftrace_disabled))
3152 p = &pg->records[i];
3153 p->flags = rec_flags;
3156 * Do the initial record conversion from mcount jump
3157 * to the NOP instructions.
3159 if (init_nop && !ftrace_nop_initialize(mod, p))
3166 stop = ftrace_now(raw_smp_processor_id());
3167 ftrace_update_time = stop - start;
3168 ftrace_update_tot_cnt += update_cnt;
3173 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3179 if (WARN_ON(!count))
3182 /* We want to fill as much as possible, with no empty pages */
3183 pages = DIV_ROUND_UP(count, ENTRIES_PER_PAGE);
3184 order = fls(pages) - 1;
3187 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3190 /* if we can't allocate this size, try something smaller */
3197 ftrace_number_of_pages += 1 << order;
3198 ftrace_number_of_groups++;
3200 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3209 static struct ftrace_page *
3210 ftrace_allocate_pages(unsigned long num_to_init)
3212 struct ftrace_page *start_pg;
3213 struct ftrace_page *pg;
3219 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3224 * Try to allocate as much as possible in one continues
3225 * location that fills in all of the space. We want to
3226 * waste as little space as possible.
3229 cnt = ftrace_allocate_records(pg, num_to_init);
3237 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3250 free_pages((unsigned long)pg->records, pg->order);
3251 ftrace_number_of_pages -= 1 << pg->order;
3253 start_pg = pg->next;
3256 ftrace_number_of_groups--;
3258 pr_info("ftrace: FAILED to allocate memory for functions\n");
3262 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3264 struct ftrace_iterator {
3268 struct ftrace_page *pg;
3269 struct dyn_ftrace *func;
3270 struct ftrace_func_probe *probe;
3271 struct ftrace_func_entry *probe_entry;
3272 struct trace_parser parser;
3273 struct ftrace_hash *hash;
3274 struct ftrace_ops *ops;
3275 struct trace_array *tr;
3276 struct list_head *mod_list;
3283 t_probe_next(struct seq_file *m, loff_t *pos)
3285 struct ftrace_iterator *iter = m->private;
3286 struct trace_array *tr = iter->ops->private;
3287 struct list_head *func_probes;
3288 struct ftrace_hash *hash;
3289 struct list_head *next;
3290 struct hlist_node *hnd = NULL;
3291 struct hlist_head *hhd;
3300 func_probes = &tr->func_probes;
3301 if (list_empty(func_probes))
3305 next = func_probes->next;
3306 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3309 if (iter->probe_entry)
3310 hnd = &iter->probe_entry->hlist;
3312 hash = iter->probe->ops.func_hash->filter_hash;
3315 * A probe being registered may temporarily have an empty hash
3316 * and it's at the end of the func_probes list.
3318 if (!hash || hash == EMPTY_HASH)
3321 size = 1 << hash->size_bits;
3324 if (iter->pidx >= size) {
3325 if (iter->probe->list.next == func_probes)
3327 next = iter->probe->list.next;
3328 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3329 hash = iter->probe->ops.func_hash->filter_hash;
3330 size = 1 << hash->size_bits;
3334 hhd = &hash->buckets[iter->pidx];
3336 if (hlist_empty(hhd)) {
3352 if (WARN_ON_ONCE(!hnd))
3355 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3360 static void *t_probe_start(struct seq_file *m, loff_t *pos)
3362 struct ftrace_iterator *iter = m->private;
3366 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3369 if (iter->mod_pos > *pos)
3373 iter->probe_entry = NULL;
3375 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3376 p = t_probe_next(m, &l);
3383 /* Only set this if we have an item */
3384 iter->flags |= FTRACE_ITER_PROBE;
3390 t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3392 struct ftrace_func_entry *probe_entry;
3393 struct ftrace_probe_ops *probe_ops;
3394 struct ftrace_func_probe *probe;
3396 probe = iter->probe;
3397 probe_entry = iter->probe_entry;
3399 if (WARN_ON_ONCE(!probe || !probe_entry))
3402 probe_ops = probe->probe_ops;
3404 if (probe_ops->print)
3405 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3407 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3408 (void *)probe_ops->func);
3414 t_mod_next(struct seq_file *m, loff_t *pos)
3416 struct ftrace_iterator *iter = m->private;
3417 struct trace_array *tr = iter->tr;
3422 iter->mod_list = iter->mod_list->next;
3424 if (iter->mod_list == &tr->mod_trace ||
3425 iter->mod_list == &tr->mod_notrace) {
3426 iter->flags &= ~FTRACE_ITER_MOD;
3430 iter->mod_pos = *pos;
3435 static void *t_mod_start(struct seq_file *m, loff_t *pos)
3437 struct ftrace_iterator *iter = m->private;
3441 if (iter->func_pos > *pos)
3444 iter->mod_pos = iter->func_pos;
3446 /* probes are only available if tr is set */
3450 for (l = 0; l <= (*pos - iter->func_pos); ) {
3451 p = t_mod_next(m, &l);
3456 iter->flags &= ~FTRACE_ITER_MOD;
3457 return t_probe_start(m, pos);
3460 /* Only set this if we have an item */
3461 iter->flags |= FTRACE_ITER_MOD;
3467 t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3469 struct ftrace_mod_load *ftrace_mod;
3470 struct trace_array *tr = iter->tr;
3472 if (WARN_ON_ONCE(!iter->mod_list) ||
3473 iter->mod_list == &tr->mod_trace ||
3474 iter->mod_list == &tr->mod_notrace)
3477 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3479 if (ftrace_mod->func)
3480 seq_printf(m, "%s", ftrace_mod->func);
3484 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3490 t_func_next(struct seq_file *m, loff_t *pos)
3492 struct ftrace_iterator *iter = m->private;
3493 struct dyn_ftrace *rec = NULL;
3498 if (iter->idx >= iter->pg->index) {
3499 if (iter->pg->next) {
3500 iter->pg = iter->pg->next;
3505 rec = &iter->pg->records[iter->idx++];
3506 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3507 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3509 ((iter->flags & FTRACE_ITER_ENABLED) &&
3510 !(rec->flags & FTRACE_FL_ENABLED))) {
3520 iter->pos = iter->func_pos = *pos;
3527 t_next(struct seq_file *m, void *v, loff_t *pos)
3529 struct ftrace_iterator *iter = m->private;
3530 loff_t l = *pos; /* t_probe_start() must use original pos */
3533 if (unlikely(ftrace_disabled))
3536 if (iter->flags & FTRACE_ITER_PROBE)
3537 return t_probe_next(m, pos);
3539 if (iter->flags & FTRACE_ITER_MOD)
3540 return t_mod_next(m, pos);
3542 if (iter->flags & FTRACE_ITER_PRINTALL) {
3543 /* next must increment pos, and t_probe_start does not */
3545 return t_mod_start(m, &l);
3548 ret = t_func_next(m, pos);
3551 return t_mod_start(m, &l);
3556 static void reset_iter_read(struct ftrace_iterator *iter)
3560 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3563 static void *t_start(struct seq_file *m, loff_t *pos)
3565 struct ftrace_iterator *iter = m->private;
3569 mutex_lock(&ftrace_lock);
3571 if (unlikely(ftrace_disabled))
3575 * If an lseek was done, then reset and start from beginning.
3577 if (*pos < iter->pos)
3578 reset_iter_read(iter);
3581 * For set_ftrace_filter reading, if we have the filter
3582 * off, we can short cut and just print out that all
3583 * functions are enabled.
3585 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3586 ftrace_hash_empty(iter->hash)) {
3587 iter->func_pos = 1; /* Account for the message */
3589 return t_mod_start(m, pos);
3590 iter->flags |= FTRACE_ITER_PRINTALL;
3591 /* reset in case of seek/pread */
3592 iter->flags &= ~FTRACE_ITER_PROBE;
3596 if (iter->flags & FTRACE_ITER_MOD)
3597 return t_mod_start(m, pos);
3600 * Unfortunately, we need to restart at ftrace_pages_start
3601 * every time we let go of the ftrace_mutex. This is because
3602 * those pointers can change without the lock.
3604 iter->pg = ftrace_pages_start;
3606 for (l = 0; l <= *pos; ) {
3607 p = t_func_next(m, &l);
3613 return t_mod_start(m, pos);
3618 static void t_stop(struct seq_file *m, void *p)
3620 mutex_unlock(&ftrace_lock);
3624 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3629 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3630 struct dyn_ftrace *rec)
3634 ptr = arch_ftrace_trampoline_func(ops, rec);
3636 seq_printf(m, " ->%pS", ptr);
3639 #ifdef FTRACE_MCOUNT_MAX_OFFSET
3641 * Weak functions can still have an mcount/fentry that is saved in
3642 * the __mcount_loc section. These can be detected by having a
3643 * symbol offset of greater than FTRACE_MCOUNT_MAX_OFFSET, as the
3644 * symbol found by kallsyms is not the function that the mcount/fentry
3645 * is part of. The offset is much greater in these cases.
3647 * Test the record to make sure that the ip points to a valid kallsyms
3648 * and if not, mark it disabled.
3650 static int test_for_valid_rec(struct dyn_ftrace *rec)
3652 char str[KSYM_SYMBOL_LEN];
3653 unsigned long offset;
3656 ret = kallsyms_lookup(rec->ip, NULL, &offset, NULL, str);
3658 /* Weak functions can cause invalid addresses */
3659 if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
3660 rec->flags |= FTRACE_FL_DISABLED;
3666 static struct workqueue_struct *ftrace_check_wq __initdata;
3667 static struct work_struct ftrace_check_work __initdata;
3670 * Scan all the mcount/fentry entries to make sure they are valid.
3672 static __init void ftrace_check_work_func(struct work_struct *work)
3674 struct ftrace_page *pg;
3675 struct dyn_ftrace *rec;
3677 mutex_lock(&ftrace_lock);
3678 do_for_each_ftrace_rec(pg, rec) {
3679 test_for_valid_rec(rec);
3680 } while_for_each_ftrace_rec();
3681 mutex_unlock(&ftrace_lock);
3684 static int __init ftrace_check_for_weak_functions(void)
3686 INIT_WORK(&ftrace_check_work, ftrace_check_work_func);
3688 ftrace_check_wq = alloc_workqueue("ftrace_check_wq", WQ_UNBOUND, 0);
3690 queue_work(ftrace_check_wq, &ftrace_check_work);
3694 static int __init ftrace_check_sync(void)
3696 /* Make sure the ftrace_check updates are finished */
3697 if (ftrace_check_wq)
3698 destroy_workqueue(ftrace_check_wq);
3702 late_initcall_sync(ftrace_check_sync);
3703 subsys_initcall(ftrace_check_for_weak_functions);
3705 static int print_rec(struct seq_file *m, unsigned long ip)
3707 unsigned long offset;
3708 char str[KSYM_SYMBOL_LEN];
3712 ret = kallsyms_lookup(ip, NULL, &offset, &modname, str);
3713 /* Weak functions can cause invalid addresses */
3714 if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
3715 snprintf(str, KSYM_SYMBOL_LEN, "%s_%ld",
3716 FTRACE_INVALID_FUNCTION, offset);
3722 seq_printf(m, " [%s]", modname);
3723 return ret == NULL ? -1 : 0;
3726 static inline int test_for_valid_rec(struct dyn_ftrace *rec)
3731 static inline int print_rec(struct seq_file *m, unsigned long ip)
3733 seq_printf(m, "%ps", (void *)ip);
3738 static int t_show(struct seq_file *m, void *v)
3740 struct ftrace_iterator *iter = m->private;
3741 struct dyn_ftrace *rec;
3743 if (iter->flags & FTRACE_ITER_PROBE)
3744 return t_probe_show(m, iter);
3746 if (iter->flags & FTRACE_ITER_MOD)
3747 return t_mod_show(m, iter);
3749 if (iter->flags & FTRACE_ITER_PRINTALL) {
3750 if (iter->flags & FTRACE_ITER_NOTRACE)
3751 seq_puts(m, "#### no functions disabled ####\n");
3753 seq_puts(m, "#### all functions enabled ####\n");
3762 if (print_rec(m, rec->ip)) {
3763 /* This should only happen when a rec is disabled */
3764 WARN_ON_ONCE(!(rec->flags & FTRACE_FL_DISABLED));
3769 if (iter->flags & FTRACE_ITER_ENABLED) {
3770 struct ftrace_ops *ops;
3772 seq_printf(m, " (%ld)%s%s%s",
3773 ftrace_rec_count(rec),
3774 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3775 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ",
3776 rec->flags & FTRACE_FL_DIRECT ? " D" : " ");
3777 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3778 ops = ftrace_find_tramp_ops_any(rec);
3781 seq_printf(m, "\ttramp: %pS (%pS)",
3782 (void *)ops->trampoline,
3784 add_trampoline_func(m, ops, rec);
3785 ops = ftrace_find_tramp_ops_next(rec, ops);
3788 seq_puts(m, "\ttramp: ERROR!");
3790 add_trampoline_func(m, NULL, rec);
3792 if (rec->flags & FTRACE_FL_DIRECT) {
3793 unsigned long direct;
3795 direct = ftrace_find_rec_direct(rec->ip);
3797 seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
3806 static const struct seq_operations show_ftrace_seq_ops = {
3814 ftrace_avail_open(struct inode *inode, struct file *file)
3816 struct ftrace_iterator *iter;
3819 ret = security_locked_down(LOCKDOWN_TRACEFS);
3823 if (unlikely(ftrace_disabled))
3826 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3830 iter->pg = ftrace_pages_start;
3831 iter->ops = &global_ops;
3837 ftrace_enabled_open(struct inode *inode, struct file *file)
3839 struct ftrace_iterator *iter;
3842 * This shows us what functions are currently being
3843 * traced and by what. Not sure if we want lockdown
3844 * to hide such critical information for an admin.
3845 * Although, perhaps it can show information we don't
3846 * want people to see, but if something is tracing
3847 * something, we probably want to know about it.
3850 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3854 iter->pg = ftrace_pages_start;
3855 iter->flags = FTRACE_ITER_ENABLED;
3856 iter->ops = &global_ops;
3862 * ftrace_regex_open - initialize function tracer filter files
3863 * @ops: The ftrace_ops that hold the hash filters
3864 * @flag: The type of filter to process
3865 * @inode: The inode, usually passed in to your open routine
3866 * @file: The file, usually passed in to your open routine
3868 * ftrace_regex_open() initializes the filter files for the
3869 * @ops. Depending on @flag it may process the filter hash or
3870 * the notrace hash of @ops. With this called from the open
3871 * routine, you can use ftrace_filter_write() for the write
3872 * routine if @flag has FTRACE_ITER_FILTER set, or
3873 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3874 * tracing_lseek() should be used as the lseek routine, and
3875 * release must call ftrace_regex_release().
3878 ftrace_regex_open(struct ftrace_ops *ops, int flag,
3879 struct inode *inode, struct file *file)
3881 struct ftrace_iterator *iter;
3882 struct ftrace_hash *hash;
3883 struct list_head *mod_head;
3884 struct trace_array *tr = ops->private;
3887 ftrace_ops_init(ops);
3889 if (unlikely(ftrace_disabled))
3892 if (tracing_check_open_get_tr(tr))
3895 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3899 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
3906 mutex_lock(&ops->func_hash->regex_lock);
3908 if (flag & FTRACE_ITER_NOTRACE) {
3909 hash = ops->func_hash->notrace_hash;
3910 mod_head = tr ? &tr->mod_notrace : NULL;
3912 hash = ops->func_hash->filter_hash;
3913 mod_head = tr ? &tr->mod_trace : NULL;
3916 iter->mod_list = mod_head;
3918 if (file->f_mode & FMODE_WRITE) {
3919 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3921 if (file->f_flags & O_TRUNC) {
3922 iter->hash = alloc_ftrace_hash(size_bits);
3923 clear_ftrace_mod_list(mod_head);
3925 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3929 trace_parser_put(&iter->parser);
3937 if (file->f_mode & FMODE_READ) {
3938 iter->pg = ftrace_pages_start;
3940 ret = seq_open(file, &show_ftrace_seq_ops);
3942 struct seq_file *m = file->private_data;
3946 free_ftrace_hash(iter->hash);
3947 trace_parser_put(&iter->parser);
3950 file->private_data = iter;
3953 mutex_unlock(&ops->func_hash->regex_lock);
3959 trace_array_put(tr);
3966 ftrace_filter_open(struct inode *inode, struct file *file)
3968 struct ftrace_ops *ops = inode->i_private;
3970 /* Checks for tracefs lockdown */
3971 return ftrace_regex_open(ops,
3972 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3977 ftrace_notrace_open(struct inode *inode, struct file *file)
3979 struct ftrace_ops *ops = inode->i_private;
3981 /* Checks for tracefs lockdown */
3982 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3986 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3987 struct ftrace_glob {
3994 * If symbols in an architecture don't correspond exactly to the user-visible
3995 * name of what they represent, it is possible to define this function to
3996 * perform the necessary adjustments.
3998 char * __weak arch_ftrace_match_adjust(char *str, const char *search)
4003 static int ftrace_match(char *str, struct ftrace_glob *g)
4008 str = arch_ftrace_match_adjust(str, g->search);
4012 if (strcmp(str, g->search) == 0)
4015 case MATCH_FRONT_ONLY:
4016 if (strncmp(str, g->search, g->len) == 0)
4019 case MATCH_MIDDLE_ONLY:
4020 if (strstr(str, g->search))
4023 case MATCH_END_ONLY:
4025 if (slen >= g->len &&
4026 memcmp(str + slen - g->len, g->search, g->len) == 0)
4030 if (glob_match(g->search, str))
4039 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
4041 struct ftrace_func_entry *entry;
4044 entry = ftrace_lookup_ip(hash, rec->ip);
4046 /* Do nothing if it doesn't exist */
4050 free_hash_entry(hash, entry);
4052 /* Do nothing if it exists */
4056 ret = add_hash_entry(hash, rec->ip);
4062 add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
4065 long index = simple_strtoul(func_g->search, NULL, 0);
4066 struct ftrace_page *pg;
4067 struct dyn_ftrace *rec;
4069 /* The index starts at 1 */
4073 do_for_each_ftrace_rec(pg, rec) {
4074 if (pg->index <= index) {
4076 /* this is a double loop, break goes to the next page */
4079 rec = &pg->records[index];
4080 enter_record(hash, rec, clear_filter);
4082 } while_for_each_ftrace_rec();
4086 #ifdef FTRACE_MCOUNT_MAX_OFFSET
4087 static int lookup_ip(unsigned long ip, char **modname, char *str)
4089 unsigned long offset;
4091 kallsyms_lookup(ip, NULL, &offset, modname, str);
4092 if (offset > FTRACE_MCOUNT_MAX_OFFSET)
4097 static int lookup_ip(unsigned long ip, char **modname, char *str)
4099 kallsyms_lookup(ip, NULL, NULL, modname, str);
4105 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
4106 struct ftrace_glob *mod_g, int exclude_mod)
4108 char str[KSYM_SYMBOL_LEN];
4111 if (lookup_ip(rec->ip, &modname, str)) {
4112 /* This should only happen when a rec is disabled */
4113 WARN_ON_ONCE(system_state == SYSTEM_RUNNING &&
4114 !(rec->flags & FTRACE_FL_DISABLED));
4119 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
4121 /* blank module name to match all modules */
4123 /* blank module globbing: modname xor exclude_mod */
4124 if (!exclude_mod != !modname)
4130 * exclude_mod is set to trace everything but the given
4131 * module. If it is set and the module matches, then
4132 * return 0. If it is not set, and the module doesn't match
4133 * also return 0. Otherwise, check the function to see if
4136 if (!mod_matches == !exclude_mod)
4139 /* blank search means to match all funcs in the mod */
4144 return ftrace_match(str, func_g);
4148 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
4150 struct ftrace_page *pg;
4151 struct dyn_ftrace *rec;
4152 struct ftrace_glob func_g = { .type = MATCH_FULL };
4153 struct ftrace_glob mod_g = { .type = MATCH_FULL };
4154 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
4155 int exclude_mod = 0;
4158 int clear_filter = 0;
4161 func_g.type = filter_parse_regex(func, len, &func_g.search,
4163 func_g.len = strlen(func_g.search);
4167 mod_g.type = filter_parse_regex(mod, strlen(mod),
4168 &mod_g.search, &exclude_mod);
4169 mod_g.len = strlen(mod_g.search);
4172 mutex_lock(&ftrace_lock);
4174 if (unlikely(ftrace_disabled))
4177 if (func_g.type == MATCH_INDEX) {
4178 found = add_rec_by_index(hash, &func_g, clear_filter);
4182 do_for_each_ftrace_rec(pg, rec) {
4184 if (rec->flags & FTRACE_FL_DISABLED)
4187 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
4188 ret = enter_record(hash, rec, clear_filter);
4195 } while_for_each_ftrace_rec();
4197 mutex_unlock(&ftrace_lock);
4203 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
4205 return match_records(hash, buff, len, NULL);
4208 static void ftrace_ops_update_code(struct ftrace_ops *ops,
4209 struct ftrace_ops_hash *old_hash)
4211 struct ftrace_ops *op;
4213 if (!ftrace_enabled)
4216 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4217 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4222 * If this is the shared global_ops filter, then we need to
4223 * check if there is another ops that shares it, is enabled.
4224 * If so, we still need to run the modify code.
4226 if (ops->func_hash != &global_ops.local_hash)
4229 do_for_each_ftrace_op(op, ftrace_ops_list) {
4230 if (op->func_hash == &global_ops.local_hash &&
4231 op->flags & FTRACE_OPS_FL_ENABLED) {
4232 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4233 /* Only need to do this once */
4236 } while_for_each_ftrace_op(op);
4239 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
4240 struct ftrace_hash **orig_hash,
4241 struct ftrace_hash *hash,
4244 struct ftrace_ops_hash old_hash_ops;
4245 struct ftrace_hash *old_hash;
4248 old_hash = *orig_hash;
4249 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4250 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4251 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4253 ftrace_ops_update_code(ops, &old_hash_ops);
4254 free_ftrace_hash_rcu(old_hash);
4259 static bool module_exists(const char *module)
4261 /* All modules have the symbol __this_module */
4262 static const char this_mod[] = "__this_module";
4263 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
4267 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
4269 if (n > sizeof(modname) - 1)
4272 val = module_kallsyms_lookup_name(modname);
4276 static int cache_mod(struct trace_array *tr,
4277 const char *func, char *module, int enable)
4279 struct ftrace_mod_load *ftrace_mod, *n;
4280 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4283 mutex_lock(&ftrace_lock);
4285 /* We do not cache inverse filters */
4286 if (func[0] == '!') {
4290 /* Look to remove this hash */
4291 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4292 if (strcmp(ftrace_mod->module, module) != 0)
4295 /* no func matches all */
4296 if (strcmp(func, "*") == 0 ||
4297 (ftrace_mod->func &&
4298 strcmp(ftrace_mod->func, func) == 0)) {
4300 free_ftrace_mod(ftrace_mod);
4308 /* We only care about modules that have not been loaded yet */
4309 if (module_exists(module))
4312 /* Save this string off, and execute it when the module is loaded */
4313 ret = ftrace_add_mod(tr, func, module, enable);
4315 mutex_unlock(&ftrace_lock);
4321 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4322 int reset, int enable);
4324 #ifdef CONFIG_MODULES
4325 static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4326 char *mod, bool enable)
4328 struct ftrace_mod_load *ftrace_mod, *n;
4329 struct ftrace_hash **orig_hash, *new_hash;
4330 LIST_HEAD(process_mods);
4333 mutex_lock(&ops->func_hash->regex_lock);
4336 orig_hash = &ops->func_hash->filter_hash;
4338 orig_hash = &ops->func_hash->notrace_hash;
4340 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4343 goto out; /* warn? */
4345 mutex_lock(&ftrace_lock);
4347 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4349 if (strcmp(ftrace_mod->module, mod) != 0)
4352 if (ftrace_mod->func)
4353 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4355 func = kstrdup("*", GFP_KERNEL);
4357 if (!func) /* warn? */
4360 list_move(&ftrace_mod->list, &process_mods);
4362 /* Use the newly allocated func, as it may be "*" */
4363 kfree(ftrace_mod->func);
4364 ftrace_mod->func = func;
4367 mutex_unlock(&ftrace_lock);
4369 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4371 func = ftrace_mod->func;
4373 /* Grabs ftrace_lock, which is why we have this extra step */
4374 match_records(new_hash, func, strlen(func), mod);
4375 free_ftrace_mod(ftrace_mod);
4378 if (enable && list_empty(head))
4379 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4381 mutex_lock(&ftrace_lock);
4383 ftrace_hash_move_and_update_ops(ops, orig_hash,
4385 mutex_unlock(&ftrace_lock);
4388 mutex_unlock(&ops->func_hash->regex_lock);
4390 free_ftrace_hash(new_hash);
4393 static void process_cached_mods(const char *mod_name)
4395 struct trace_array *tr;
4398 mod = kstrdup(mod_name, GFP_KERNEL);
4402 mutex_lock(&trace_types_lock);
4403 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4404 if (!list_empty(&tr->mod_trace))
4405 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4406 if (!list_empty(&tr->mod_notrace))
4407 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4409 mutex_unlock(&trace_types_lock);
4416 * We register the module command as a template to show others how
4417 * to register the a command as well.
4421 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4422 char *func_orig, char *cmd, char *module, int enable)
4427 /* match_records() modifies func, and we need the original */
4428 func = kstrdup(func_orig, GFP_KERNEL);
4433 * cmd == 'mod' because we only registered this func
4434 * for the 'mod' ftrace_func_command.
4435 * But if you register one func with multiple commands,
4436 * you can tell which command was used by the cmd
4439 ret = match_records(hash, func, strlen(func), module);
4443 return cache_mod(tr, func_orig, module, enable);
4449 static struct ftrace_func_command ftrace_mod_cmd = {
4451 .func = ftrace_mod_callback,
4454 static int __init ftrace_mod_cmd_init(void)
4456 return register_ftrace_command(&ftrace_mod_cmd);
4458 core_initcall(ftrace_mod_cmd_init);
4460 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4461 struct ftrace_ops *op, struct ftrace_regs *fregs)
4463 struct ftrace_probe_ops *probe_ops;
4464 struct ftrace_func_probe *probe;
4466 probe = container_of(op, struct ftrace_func_probe, ops);
4467 probe_ops = probe->probe_ops;
4470 * Disable preemption for these calls to prevent a RCU grace
4471 * period. This syncs the hash iteration and freeing of items
4472 * on the hash. rcu_read_lock is too dangerous here.
4474 preempt_disable_notrace();
4475 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4476 preempt_enable_notrace();
4479 struct ftrace_func_map {
4480 struct ftrace_func_entry entry;
4484 struct ftrace_func_mapper {
4485 struct ftrace_hash hash;
4489 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4491 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4493 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4495 struct ftrace_hash *hash;
4498 * The mapper is simply a ftrace_hash, but since the entries
4499 * in the hash are not ftrace_func_entry type, we define it
4500 * as a separate structure.
4502 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4503 return (struct ftrace_func_mapper *)hash;
4507 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4508 * @mapper: The mapper that has the ip maps
4509 * @ip: the instruction pointer to find the data for
4511 * Returns the data mapped to @ip if found otherwise NULL. The return
4512 * is actually the address of the mapper data pointer. The address is
4513 * returned for use cases where the data is no bigger than a long, and
4514 * the user can use the data pointer as its data instead of having to
4515 * allocate more memory for the reference.
4517 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4520 struct ftrace_func_entry *entry;
4521 struct ftrace_func_map *map;
4523 entry = ftrace_lookup_ip(&mapper->hash, ip);
4527 map = (struct ftrace_func_map *)entry;
4532 * ftrace_func_mapper_add_ip - Map some data to an ip
4533 * @mapper: The mapper that has the ip maps
4534 * @ip: The instruction pointer address to map @data to
4535 * @data: The data to map to @ip
4537 * Returns 0 on success otherwise an error.
4539 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4540 unsigned long ip, void *data)
4542 struct ftrace_func_entry *entry;
4543 struct ftrace_func_map *map;
4545 entry = ftrace_lookup_ip(&mapper->hash, ip);
4549 map = kmalloc(sizeof(*map), GFP_KERNEL);
4556 __add_hash_entry(&mapper->hash, &map->entry);
4562 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4563 * @mapper: The mapper that has the ip maps
4564 * @ip: The instruction pointer address to remove the data from
4566 * Returns the data if it is found, otherwise NULL.
4567 * Note, if the data pointer is used as the data itself, (see
4568 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4569 * if the data pointer was set to zero.
4571 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4574 struct ftrace_func_entry *entry;
4575 struct ftrace_func_map *map;
4578 entry = ftrace_lookup_ip(&mapper->hash, ip);
4582 map = (struct ftrace_func_map *)entry;
4585 remove_hash_entry(&mapper->hash, entry);
4592 * free_ftrace_func_mapper - free a mapping of ips and data
4593 * @mapper: The mapper that has the ip maps
4594 * @free_func: A function to be called on each data item.
4596 * This is used to free the function mapper. The @free_func is optional
4597 * and can be used if the data needs to be freed as well.
4599 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4600 ftrace_mapper_func free_func)
4602 struct ftrace_func_entry *entry;
4603 struct ftrace_func_map *map;
4604 struct hlist_head *hhd;
4610 if (free_func && mapper->hash.count) {
4611 size = 1 << mapper->hash.size_bits;
4612 for (i = 0; i < size; i++) {
4613 hhd = &mapper->hash.buckets[i];
4614 hlist_for_each_entry(entry, hhd, hlist) {
4615 map = (struct ftrace_func_map *)entry;
4620 free_ftrace_hash(&mapper->hash);
4623 static void release_probe(struct ftrace_func_probe *probe)
4625 struct ftrace_probe_ops *probe_ops;
4627 mutex_lock(&ftrace_lock);
4629 WARN_ON(probe->ref <= 0);
4631 /* Subtract the ref that was used to protect this instance */
4635 probe_ops = probe->probe_ops;
4637 * Sending zero as ip tells probe_ops to free
4638 * the probe->data itself
4640 if (probe_ops->free)
4641 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4642 list_del(&probe->list);
4645 mutex_unlock(&ftrace_lock);
4648 static void acquire_probe_locked(struct ftrace_func_probe *probe)
4651 * Add one ref to keep it from being freed when releasing the
4652 * ftrace_lock mutex.
4658 register_ftrace_function_probe(char *glob, struct trace_array *tr,
4659 struct ftrace_probe_ops *probe_ops,
4662 struct ftrace_func_probe *probe = NULL, *iter;
4663 struct ftrace_func_entry *entry;
4664 struct ftrace_hash **orig_hash;
4665 struct ftrace_hash *old_hash;
4666 struct ftrace_hash *hash;
4675 /* We do not support '!' for function probes */
4676 if (WARN_ON(glob[0] == '!'))
4680 mutex_lock(&ftrace_lock);
4681 /* Check if the probe_ops is already registered */
4682 list_for_each_entry(iter, &tr->func_probes, list) {
4683 if (iter->probe_ops == probe_ops) {
4689 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4691 mutex_unlock(&ftrace_lock);
4694 probe->probe_ops = probe_ops;
4695 probe->ops.func = function_trace_probe_call;
4697 ftrace_ops_init(&probe->ops);
4698 list_add(&probe->list, &tr->func_probes);
4701 acquire_probe_locked(probe);
4703 mutex_unlock(&ftrace_lock);
4706 * Note, there's a small window here that the func_hash->filter_hash
4707 * may be NULL or empty. Need to be careful when reading the loop.
4709 mutex_lock(&probe->ops.func_hash->regex_lock);
4711 orig_hash = &probe->ops.func_hash->filter_hash;
4712 old_hash = *orig_hash;
4713 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4720 ret = ftrace_match_records(hash, glob, strlen(glob));
4722 /* Nothing found? */
4729 size = 1 << hash->size_bits;
4730 for (i = 0; i < size; i++) {
4731 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4732 if (ftrace_lookup_ip(old_hash, entry->ip))
4735 * The caller might want to do something special
4736 * for each function we find. We call the callback
4737 * to give the caller an opportunity to do so.
4739 if (probe_ops->init) {
4740 ret = probe_ops->init(probe_ops, tr,
4744 if (probe_ops->free && count)
4745 probe_ops->free(probe_ops, tr,
4755 mutex_lock(&ftrace_lock);
4758 /* Nothing was added? */
4763 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4768 /* One ref for each new function traced */
4769 probe->ref += count;
4771 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4772 ret = ftrace_startup(&probe->ops, 0);
4775 mutex_unlock(&ftrace_lock);
4780 mutex_unlock(&probe->ops.func_hash->regex_lock);
4781 free_ftrace_hash(hash);
4783 release_probe(probe);
4788 if (!probe_ops->free || !count)
4791 /* Failed to do the move, need to call the free functions */
4792 for (i = 0; i < size; i++) {
4793 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4794 if (ftrace_lookup_ip(old_hash, entry->ip))
4796 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4803 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4804 struct ftrace_probe_ops *probe_ops)
4806 struct ftrace_func_probe *probe = NULL, *iter;
4807 struct ftrace_ops_hash old_hash_ops;
4808 struct ftrace_func_entry *entry;
4809 struct ftrace_glob func_g;
4810 struct ftrace_hash **orig_hash;
4811 struct ftrace_hash *old_hash;
4812 struct ftrace_hash *hash = NULL;
4813 struct hlist_node *tmp;
4814 struct hlist_head hhd;
4815 char str[KSYM_SYMBOL_LEN];
4817 int i, ret = -ENODEV;
4820 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4821 func_g.search = NULL;
4825 func_g.type = filter_parse_regex(glob, strlen(glob),
4826 &func_g.search, ¬);
4827 func_g.len = strlen(func_g.search);
4829 /* we do not support '!' for function probes */
4834 mutex_lock(&ftrace_lock);
4835 /* Check if the probe_ops is already registered */
4836 list_for_each_entry(iter, &tr->func_probes, list) {
4837 if (iter->probe_ops == probe_ops) {
4843 goto err_unlock_ftrace;
4846 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4847 goto err_unlock_ftrace;
4849 acquire_probe_locked(probe);
4851 mutex_unlock(&ftrace_lock);
4853 mutex_lock(&probe->ops.func_hash->regex_lock);
4855 orig_hash = &probe->ops.func_hash->filter_hash;
4856 old_hash = *orig_hash;
4858 if (ftrace_hash_empty(old_hash))
4861 old_hash_ops.filter_hash = old_hash;
4862 /* Probes only have filters */
4863 old_hash_ops.notrace_hash = NULL;
4866 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4870 INIT_HLIST_HEAD(&hhd);
4872 size = 1 << hash->size_bits;
4873 for (i = 0; i < size; i++) {
4874 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4876 if (func_g.search) {
4877 kallsyms_lookup(entry->ip, NULL, NULL,
4879 if (!ftrace_match(str, &func_g))
4883 remove_hash_entry(hash, entry);
4884 hlist_add_head(&entry->hlist, &hhd);
4888 /* Nothing found? */
4894 mutex_lock(&ftrace_lock);
4896 WARN_ON(probe->ref < count);
4898 probe->ref -= count;
4900 if (ftrace_hash_empty(hash))
4901 ftrace_shutdown(&probe->ops, 0);
4903 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4906 /* still need to update the function call sites */
4907 if (ftrace_enabled && !ftrace_hash_empty(hash))
4908 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4912 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4913 hlist_del(&entry->hlist);
4914 if (probe_ops->free)
4915 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4918 mutex_unlock(&ftrace_lock);
4921 mutex_unlock(&probe->ops.func_hash->regex_lock);
4922 free_ftrace_hash(hash);
4924 release_probe(probe);
4929 mutex_unlock(&ftrace_lock);
4933 void clear_ftrace_function_probes(struct trace_array *tr)
4935 struct ftrace_func_probe *probe, *n;
4937 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4938 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
4941 static LIST_HEAD(ftrace_commands);
4942 static DEFINE_MUTEX(ftrace_cmd_mutex);
4945 * Currently we only register ftrace commands from __init, so mark this
4948 __init int register_ftrace_command(struct ftrace_func_command *cmd)
4950 struct ftrace_func_command *p;
4953 mutex_lock(&ftrace_cmd_mutex);
4954 list_for_each_entry(p, &ftrace_commands, list) {
4955 if (strcmp(cmd->name, p->name) == 0) {
4960 list_add(&cmd->list, &ftrace_commands);
4962 mutex_unlock(&ftrace_cmd_mutex);
4968 * Currently we only unregister ftrace commands from __init, so mark
4971 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4973 struct ftrace_func_command *p, *n;
4976 mutex_lock(&ftrace_cmd_mutex);
4977 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4978 if (strcmp(cmd->name, p->name) == 0) {
4980 list_del_init(&p->list);
4985 mutex_unlock(&ftrace_cmd_mutex);
4990 static int ftrace_process_regex(struct ftrace_iterator *iter,
4991 char *buff, int len, int enable)
4993 struct ftrace_hash *hash = iter->hash;
4994 struct trace_array *tr = iter->ops->private;
4995 char *func, *command, *next = buff;
4996 struct ftrace_func_command *p;
4999 func = strsep(&next, ":");
5002 ret = ftrace_match_records(hash, func, len);
5012 command = strsep(&next, ":");
5014 mutex_lock(&ftrace_cmd_mutex);
5015 list_for_each_entry(p, &ftrace_commands, list) {
5016 if (strcmp(p->name, command) == 0) {
5017 ret = p->func(tr, hash, func, command, next, enable);
5022 mutex_unlock(&ftrace_cmd_mutex);
5028 ftrace_regex_write(struct file *file, const char __user *ubuf,
5029 size_t cnt, loff_t *ppos, int enable)
5031 struct ftrace_iterator *iter;
5032 struct trace_parser *parser;
5038 if (file->f_mode & FMODE_READ) {
5039 struct seq_file *m = file->private_data;
5042 iter = file->private_data;
5044 if (unlikely(ftrace_disabled))
5047 /* iter->hash is a local copy, so we don't need regex_lock */
5049 parser = &iter->parser;
5050 read = trace_get_user(parser, ubuf, cnt, ppos);
5052 if (read >= 0 && trace_parser_loaded(parser) &&
5053 !trace_parser_cont(parser)) {
5054 ret = ftrace_process_regex(iter, parser->buffer,
5055 parser->idx, enable);
5056 trace_parser_clear(parser);
5067 ftrace_filter_write(struct file *file, const char __user *ubuf,
5068 size_t cnt, loff_t *ppos)
5070 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
5074 ftrace_notrace_write(struct file *file, const char __user *ubuf,
5075 size_t cnt, loff_t *ppos)
5077 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
5081 __ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
5083 struct ftrace_func_entry *entry;
5085 ip = ftrace_location(ip);
5090 entry = ftrace_lookup_ip(hash, ip);
5093 free_hash_entry(hash, entry);
5097 return add_hash_entry(hash, ip);
5101 ftrace_match_addr(struct ftrace_hash *hash, unsigned long *ips,
5102 unsigned int cnt, int remove)
5107 for (i = 0; i < cnt; i++) {
5108 err = __ftrace_match_addr(hash, ips[i], remove);
5111 * This expects the @hash is a temporary hash and if this
5112 * fails the caller must free the @hash.
5121 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
5122 unsigned long *ips, unsigned int cnt,
5123 int remove, int reset, int enable)
5125 struct ftrace_hash **orig_hash;
5126 struct ftrace_hash *hash;
5129 if (unlikely(ftrace_disabled))
5132 mutex_lock(&ops->func_hash->regex_lock);
5135 orig_hash = &ops->func_hash->filter_hash;
5137 orig_hash = &ops->func_hash->notrace_hash;
5140 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5142 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
5146 goto out_regex_unlock;
5149 if (buf && !ftrace_match_records(hash, buf, len)) {
5151 goto out_regex_unlock;
5154 ret = ftrace_match_addr(hash, ips, cnt, remove);
5156 goto out_regex_unlock;
5159 mutex_lock(&ftrace_lock);
5160 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
5161 mutex_unlock(&ftrace_lock);
5164 mutex_unlock(&ops->func_hash->regex_lock);
5166 free_ftrace_hash(hash);
5171 ftrace_set_addr(struct ftrace_ops *ops, unsigned long *ips, unsigned int cnt,
5172 int remove, int reset, int enable)
5174 return ftrace_set_hash(ops, NULL, 0, ips, cnt, remove, reset, enable);
5177 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
5179 struct ftrace_direct_func {
5180 struct list_head next;
5185 static LIST_HEAD(ftrace_direct_funcs);
5188 * ftrace_find_direct_func - test an address if it is a registered direct caller
5189 * @addr: The address of a registered direct caller
5191 * This searches to see if a ftrace direct caller has been registered
5192 * at a specific address, and if so, it returns a descriptor for it.
5194 * This can be used by architecture code to see if an address is
5195 * a direct caller (trampoline) attached to a fentry/mcount location.
5196 * This is useful for the function_graph tracer, as it may need to
5197 * do adjustments if it traced a location that also has a direct
5198 * trampoline attached to it.
5200 struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
5202 struct ftrace_direct_func *entry;
5205 /* May be called by fgraph trampoline (protected by rcu tasks) */
5206 list_for_each_entry_rcu(entry, &ftrace_direct_funcs, next) {
5207 if (entry->addr == addr) {
5218 static struct ftrace_direct_func *ftrace_alloc_direct_func(unsigned long addr)
5220 struct ftrace_direct_func *direct;
5222 direct = kmalloc(sizeof(*direct), GFP_KERNEL);
5225 direct->addr = addr;
5227 list_add_rcu(&direct->next, &ftrace_direct_funcs);
5228 ftrace_direct_func_count++;
5232 static int register_ftrace_function_nolock(struct ftrace_ops *ops);
5235 * register_ftrace_direct - Call a custom trampoline directly
5236 * @ip: The address of the nop at the beginning of a function
5237 * @addr: The address of the trampoline to call at @ip
5239 * This is used to connect a direct call from the nop location (@ip)
5240 * at the start of ftrace traced functions. The location that it calls
5241 * (@addr) must be able to handle a direct call, and save the parameters
5242 * of the function being traced, and restore them (or inject new ones
5243 * if needed), before returning.
5247 * -EBUSY - Another direct function is already attached (there can be only one)
5248 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
5249 * -ENOMEM - There was an allocation failure.
5251 int register_ftrace_direct(unsigned long ip, unsigned long addr)
5253 struct ftrace_direct_func *direct;
5254 struct ftrace_func_entry *entry;
5255 struct ftrace_hash *free_hash = NULL;
5256 struct dyn_ftrace *rec;
5259 mutex_lock(&direct_mutex);
5261 ip = ftrace_location(ip);
5265 /* See if there's a direct function at @ip already */
5267 if (ftrace_find_rec_direct(ip))
5271 rec = lookup_rec(ip, ip);
5276 * Check if the rec says it has a direct call but we didn't
5279 if (WARN_ON(rec->flags & FTRACE_FL_DIRECT))
5282 /* Make sure the ip points to the exact record */
5283 if (ip != rec->ip) {
5285 /* Need to check this ip for a direct. */
5286 if (ftrace_find_rec_direct(ip))
5291 direct = ftrace_find_direct_func(addr);
5293 direct = ftrace_alloc_direct_func(addr);
5298 entry = ftrace_add_rec_direct(ip, addr, &free_hash);
5302 ret = ftrace_set_filter_ip(&direct_ops, ip, 0, 0);
5304 if (!ret && !(direct_ops.flags & FTRACE_OPS_FL_ENABLED)) {
5305 ret = register_ftrace_function_nolock(&direct_ops);
5307 ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5311 remove_hash_entry(direct_functions, entry);
5313 if (!direct->count) {
5314 list_del_rcu(&direct->next);
5315 synchronize_rcu_tasks();
5318 free_ftrace_hash(free_hash);
5320 ftrace_direct_func_count--;
5326 mutex_unlock(&direct_mutex);
5329 synchronize_rcu_tasks();
5330 free_ftrace_hash(free_hash);
5335 EXPORT_SYMBOL_GPL(register_ftrace_direct);
5337 static struct ftrace_func_entry *find_direct_entry(unsigned long *ip,
5338 struct dyn_ftrace **recp)
5340 struct ftrace_func_entry *entry;
5341 struct dyn_ftrace *rec;
5343 rec = lookup_rec(*ip, *ip);
5347 entry = __ftrace_lookup_ip(direct_functions, rec->ip);
5349 WARN_ON(rec->flags & FTRACE_FL_DIRECT);
5353 WARN_ON(!(rec->flags & FTRACE_FL_DIRECT));
5355 /* Passed in ip just needs to be on the call site */
5364 int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
5366 struct ftrace_direct_func *direct;
5367 struct ftrace_func_entry *entry;
5368 struct ftrace_hash *hash;
5371 mutex_lock(&direct_mutex);
5373 ip = ftrace_location(ip);
5377 entry = find_direct_entry(&ip, NULL);
5381 hash = direct_ops.func_hash->filter_hash;
5382 if (hash->count == 1)
5383 unregister_ftrace_function(&direct_ops);
5385 ret = ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5389 remove_hash_entry(direct_functions, entry);
5391 direct = ftrace_find_direct_func(addr);
5392 if (!WARN_ON(!direct)) {
5393 /* This is the good path (see the ! before WARN) */
5395 WARN_ON(direct->count < 0);
5396 if (!direct->count) {
5397 list_del_rcu(&direct->next);
5398 synchronize_rcu_tasks();
5401 ftrace_direct_func_count--;
5405 mutex_unlock(&direct_mutex);
5409 EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
5411 static struct ftrace_ops stub_ops = {
5412 .func = ftrace_stub,
5416 * ftrace_modify_direct_caller - modify ftrace nop directly
5417 * @entry: The ftrace hash entry of the direct helper for @rec
5418 * @rec: The record representing the function site to patch
5419 * @old_addr: The location that the site at @rec->ip currently calls
5420 * @new_addr: The location that the site at @rec->ip should call
5422 * An architecture may overwrite this function to optimize the
5423 * changing of the direct callback on an ftrace nop location.
5424 * This is called with the ftrace_lock mutex held, and no other
5425 * ftrace callbacks are on the associated record (@rec). Thus,
5426 * it is safe to modify the ftrace record, where it should be
5427 * currently calling @old_addr directly, to call @new_addr.
5429 * This is called with direct_mutex locked.
5431 * Safety checks should be made to make sure that the code at
5432 * @rec->ip is currently calling @old_addr. And this must
5433 * also update entry->direct to @new_addr.
5435 int __weak ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
5436 struct dyn_ftrace *rec,
5437 unsigned long old_addr,
5438 unsigned long new_addr)
5440 unsigned long ip = rec->ip;
5443 lockdep_assert_held(&direct_mutex);
5446 * The ftrace_lock was used to determine if the record
5447 * had more than one registered user to it. If it did,
5448 * we needed to prevent that from changing to do the quick
5449 * switch. But if it did not (only a direct caller was attached)
5450 * then this function is called. But this function can deal
5451 * with attached callers to the rec that we care about, and
5452 * since this function uses standard ftrace calls that take
5453 * the ftrace_lock mutex, we need to release it.
5455 mutex_unlock(&ftrace_lock);
5458 * By setting a stub function at the same address, we force
5459 * the code to call the iterator and the direct_ops helper.
5460 * This means that @ip does not call the direct call, and
5461 * we can simply modify it.
5463 ret = ftrace_set_filter_ip(&stub_ops, ip, 0, 0);
5467 ret = register_ftrace_function_nolock(&stub_ops);
5469 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5473 entry->direct = new_addr;
5476 * By removing the stub, we put back the direct call, calling
5479 unregister_ftrace_function(&stub_ops);
5480 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5483 mutex_lock(&ftrace_lock);
5489 * modify_ftrace_direct - Modify an existing direct call to call something else
5490 * @ip: The instruction pointer to modify
5491 * @old_addr: The address that the current @ip calls directly
5492 * @new_addr: The address that the @ip should call
5494 * This modifies a ftrace direct caller at an instruction pointer without
5495 * having to disable it first. The direct call will switch over to the
5496 * @new_addr without missing anything.
5498 * Returns: zero on success. Non zero on error, which includes:
5499 * -ENODEV : the @ip given has no direct caller attached
5500 * -EINVAL : the @old_addr does not match the current direct caller
5502 int modify_ftrace_direct(unsigned long ip,
5503 unsigned long old_addr, unsigned long new_addr)
5505 struct ftrace_direct_func *direct, *new_direct = NULL;
5506 struct ftrace_func_entry *entry;
5507 struct dyn_ftrace *rec;
5510 mutex_lock(&direct_mutex);
5512 mutex_lock(&ftrace_lock);
5514 ip = ftrace_location(ip);
5518 entry = find_direct_entry(&ip, &rec);
5523 if (entry->direct != old_addr)
5526 direct = ftrace_find_direct_func(old_addr);
5527 if (WARN_ON(!direct))
5529 if (direct->count > 1) {
5531 new_direct = ftrace_alloc_direct_func(new_addr);
5535 new_direct->count++;
5537 direct->addr = new_addr;
5541 * If there's no other ftrace callback on the rec->ip location,
5542 * then it can be changed directly by the architecture.
5543 * If there is another caller, then we just need to change the
5544 * direct caller helper to point to @new_addr.
5546 if (ftrace_rec_count(rec) == 1) {
5547 ret = ftrace_modify_direct_caller(entry, rec, old_addr, new_addr);
5549 entry->direct = new_addr;
5553 if (unlikely(ret && new_direct)) {
5555 list_del_rcu(&new_direct->next);
5556 synchronize_rcu_tasks();
5558 ftrace_direct_func_count--;
5562 mutex_unlock(&ftrace_lock);
5563 mutex_unlock(&direct_mutex);
5566 EXPORT_SYMBOL_GPL(modify_ftrace_direct);
5568 #define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS)
5570 static int check_direct_multi(struct ftrace_ops *ops)
5572 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5574 if ((ops->flags & MULTI_FLAGS) != MULTI_FLAGS)
5579 static void remove_direct_functions_hash(struct ftrace_hash *hash, unsigned long addr)
5581 struct ftrace_func_entry *entry, *del;
5584 size = 1 << hash->size_bits;
5585 for (i = 0; i < size; i++) {
5586 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5587 del = __ftrace_lookup_ip(direct_functions, entry->ip);
5588 if (del && del->direct == addr) {
5589 remove_hash_entry(direct_functions, del);
5597 * register_ftrace_direct_multi - Call a custom trampoline directly
5598 * for multiple functions registered in @ops
5599 * @ops: The address of the struct ftrace_ops object
5600 * @addr: The address of the trampoline to call at @ops functions
5602 * This is used to connect a direct calls to @addr from the nop locations
5603 * of the functions registered in @ops (with by ftrace_set_filter_ip
5606 * The location that it calls (@addr) must be able to handle a direct call,
5607 * and save the parameters of the function being traced, and restore them
5608 * (or inject new ones if needed), before returning.
5612 * -EINVAL - The @ops object was already registered with this call or
5613 * when there are no functions in @ops object.
5614 * -EBUSY - Another direct function is already attached (there can be only one)
5615 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
5616 * -ENOMEM - There was an allocation failure.
5618 int register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
5620 struct ftrace_hash *hash, *free_hash = NULL;
5621 struct ftrace_func_entry *entry, *new;
5622 int err = -EBUSY, size, i;
5624 if (ops->func || ops->trampoline)
5626 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5628 if (ops->flags & FTRACE_OPS_FL_ENABLED)
5631 hash = ops->func_hash->filter_hash;
5632 if (ftrace_hash_empty(hash))
5635 mutex_lock(&direct_mutex);
5637 /* Make sure requested entries are not already registered.. */
5638 size = 1 << hash->size_bits;
5639 for (i = 0; i < size; i++) {
5640 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5641 if (ftrace_find_rec_direct(entry->ip))
5646 /* ... and insert them to direct_functions hash. */
5648 for (i = 0; i < size; i++) {
5649 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5650 new = ftrace_add_rec_direct(entry->ip, addr, &free_hash);
5653 entry->direct = addr;
5657 ops->func = call_direct_funcs;
5658 ops->flags = MULTI_FLAGS;
5659 ops->trampoline = FTRACE_REGS_ADDR;
5661 err = register_ftrace_function_nolock(ops);
5665 remove_direct_functions_hash(hash, addr);
5668 mutex_unlock(&direct_mutex);
5671 synchronize_rcu_tasks();
5672 free_ftrace_hash(free_hash);
5676 EXPORT_SYMBOL_GPL(register_ftrace_direct_multi);
5679 * unregister_ftrace_direct_multi - Remove calls to custom trampoline
5680 * previously registered by register_ftrace_direct_multi for @ops object.
5681 * @ops: The address of the struct ftrace_ops object
5683 * This is used to remove a direct calls to @addr from the nop locations
5684 * of the functions registered in @ops (with by ftrace_set_filter_ip
5689 * -EINVAL - The @ops object was not properly registered.
5691 int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
5693 struct ftrace_hash *hash = ops->func_hash->filter_hash;
5696 if (check_direct_multi(ops))
5698 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5701 mutex_lock(&direct_mutex);
5702 err = unregister_ftrace_function(ops);
5703 remove_direct_functions_hash(hash, addr);
5704 mutex_unlock(&direct_mutex);
5706 /* cleanup for possible another register call */
5708 ops->trampoline = 0;
5711 EXPORT_SYMBOL_GPL(unregister_ftrace_direct_multi);
5714 __modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
5716 struct ftrace_hash *hash;
5717 struct ftrace_func_entry *entry, *iter;
5718 static struct ftrace_ops tmp_ops = {
5719 .func = ftrace_stub,
5720 .flags = FTRACE_OPS_FL_STUB,
5725 lockdep_assert_held_once(&direct_mutex);
5727 /* Enable the tmp_ops to have the same functions as the direct ops */
5728 ftrace_ops_init(&tmp_ops);
5729 tmp_ops.func_hash = ops->func_hash;
5731 err = register_ftrace_function_nolock(&tmp_ops);
5736 * Now the ftrace_ops_list_func() is called to do the direct callers.
5737 * We can safely change the direct functions attached to each entry.
5739 mutex_lock(&ftrace_lock);
5741 hash = ops->func_hash->filter_hash;
5742 size = 1 << hash->size_bits;
5743 for (i = 0; i < size; i++) {
5744 hlist_for_each_entry(iter, &hash->buckets[i], hlist) {
5745 entry = __ftrace_lookup_ip(direct_functions, iter->ip);
5748 entry->direct = addr;
5752 mutex_unlock(&ftrace_lock);
5754 /* Removing the tmp_ops will add the updated direct callers to the functions */
5755 unregister_ftrace_function(&tmp_ops);
5761 * modify_ftrace_direct_multi_nolock - Modify an existing direct 'multi' call
5762 * to call something else
5763 * @ops: The address of the struct ftrace_ops object
5764 * @addr: The address of the new trampoline to call at @ops functions
5766 * This is used to unregister currently registered direct caller and
5767 * register new one @addr on functions registered in @ops object.
5769 * Note there's window between ftrace_shutdown and ftrace_startup calls
5770 * where there will be no callbacks called.
5772 * Caller should already have direct_mutex locked, so we don't lock
5773 * direct_mutex here.
5775 * Returns: zero on success. Non zero on error, which includes:
5776 * -EINVAL - The @ops object was not properly registered.
5778 int modify_ftrace_direct_multi_nolock(struct ftrace_ops *ops, unsigned long addr)
5780 if (check_direct_multi(ops))
5782 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5785 return __modify_ftrace_direct_multi(ops, addr);
5787 EXPORT_SYMBOL_GPL(modify_ftrace_direct_multi_nolock);
5790 * modify_ftrace_direct_multi - Modify an existing direct 'multi' call
5791 * to call something else
5792 * @ops: The address of the struct ftrace_ops object
5793 * @addr: The address of the new trampoline to call at @ops functions
5795 * This is used to unregister currently registered direct caller and
5796 * register new one @addr on functions registered in @ops object.
5798 * Note there's window between ftrace_shutdown and ftrace_startup calls
5799 * where there will be no callbacks called.
5801 * Returns: zero on success. Non zero on error, which includes:
5802 * -EINVAL - The @ops object was not properly registered.
5804 int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
5808 if (check_direct_multi(ops))
5810 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5813 mutex_lock(&direct_mutex);
5814 err = __modify_ftrace_direct_multi(ops, addr);
5815 mutex_unlock(&direct_mutex);
5818 EXPORT_SYMBOL_GPL(modify_ftrace_direct_multi);
5819 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
5822 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
5823 * @ops - the ops to set the filter with
5824 * @ip - the address to add to or remove from the filter.
5825 * @remove - non zero to remove the ip from the filter
5826 * @reset - non zero to reset all filters before applying this filter.
5828 * Filters denote which functions should be enabled when tracing is enabled
5829 * If @ip is NULL, it fails to update filter.
5831 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
5832 int remove, int reset)
5834 ftrace_ops_init(ops);
5835 return ftrace_set_addr(ops, &ip, 1, remove, reset, 1);
5837 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
5840 * ftrace_set_filter_ips - set functions to filter on in ftrace by addresses
5841 * @ops - the ops to set the filter with
5842 * @ips - the array of addresses to add to or remove from the filter.
5843 * @cnt - the number of addresses in @ips
5844 * @remove - non zero to remove ips from the filter
5845 * @reset - non zero to reset all filters before applying this filter.
5847 * Filters denote which functions should be enabled when tracing is enabled
5848 * If @ips array or any ip specified within is NULL , it fails to update filter.
5850 int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips,
5851 unsigned int cnt, int remove, int reset)
5853 ftrace_ops_init(ops);
5854 return ftrace_set_addr(ops, ips, cnt, remove, reset, 1);
5856 EXPORT_SYMBOL_GPL(ftrace_set_filter_ips);
5859 * ftrace_ops_set_global_filter - setup ops to use global filters
5860 * @ops - the ops which will use the global filters
5862 * ftrace users who need global function trace filtering should call this.
5863 * It can set the global filter only if ops were not initialized before.
5865 void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
5867 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
5870 ftrace_ops_init(ops);
5871 ops->func_hash = &global_ops.local_hash;
5873 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
5876 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
5877 int reset, int enable)
5879 return ftrace_set_hash(ops, buf, len, NULL, 0, 0, reset, enable);
5883 * ftrace_set_filter - set a function to filter on in ftrace
5884 * @ops - the ops to set the filter with
5885 * @buf - the string that holds the function filter text.
5886 * @len - the length of the string.
5887 * @reset - non zero to reset all filters before applying this filter.
5889 * Filters denote which functions should be enabled when tracing is enabled.
5890 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5892 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
5895 ftrace_ops_init(ops);
5896 return ftrace_set_regex(ops, buf, len, reset, 1);
5898 EXPORT_SYMBOL_GPL(ftrace_set_filter);
5901 * ftrace_set_notrace - set a function to not trace in ftrace
5902 * @ops - the ops to set the notrace filter with
5903 * @buf - the string that holds the function notrace text.
5904 * @len - the length of the string.
5905 * @reset - non zero to reset all filters before applying this filter.
5907 * Notrace Filters denote which functions should not be enabled when tracing
5908 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5911 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
5914 ftrace_ops_init(ops);
5915 return ftrace_set_regex(ops, buf, len, reset, 0);
5917 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
5919 * ftrace_set_global_filter - set a function to filter on with global tracers
5920 * @buf - the string that holds the function filter text.
5921 * @len - the length of the string.
5922 * @reset - non zero to reset all filters before applying this filter.
5924 * Filters denote which functions should be enabled when tracing is enabled.
5925 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5927 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
5929 ftrace_set_regex(&global_ops, buf, len, reset, 1);
5931 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
5934 * ftrace_set_global_notrace - set a function to not trace with global tracers
5935 * @buf - the string that holds the function notrace text.
5936 * @len - the length of the string.
5937 * @reset - non zero to reset all filters before applying this filter.
5939 * Notrace Filters denote which functions should not be enabled when tracing
5940 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5943 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
5945 ftrace_set_regex(&global_ops, buf, len, reset, 0);
5947 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
5950 * command line interface to allow users to set filters on boot up.
5952 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
5953 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5954 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
5956 /* Used by function selftest to not test if filter is set */
5957 bool ftrace_filter_param __initdata;
5959 static int __init set_ftrace_notrace(char *str)
5961 ftrace_filter_param = true;
5962 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
5965 __setup("ftrace_notrace=", set_ftrace_notrace);
5967 static int __init set_ftrace_filter(char *str)
5969 ftrace_filter_param = true;
5970 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
5973 __setup("ftrace_filter=", set_ftrace_filter);
5975 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5976 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
5977 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5978 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
5980 static int __init set_graph_function(char *str)
5982 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
5985 __setup("ftrace_graph_filter=", set_graph_function);
5987 static int __init set_graph_notrace_function(char *str)
5989 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
5992 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
5994 static int __init set_graph_max_depth_function(char *str)
5998 fgraph_max_depth = simple_strtoul(str, NULL, 0);
6001 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
6003 static void __init set_ftrace_early_graph(char *buf, int enable)
6007 struct ftrace_hash *hash;
6009 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
6010 if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
6014 func = strsep(&buf, ",");
6015 /* we allow only one expression at a time */
6016 ret = ftrace_graph_set_hash(hash, func);
6018 printk(KERN_DEBUG "ftrace: function %s not "
6019 "traceable\n", func);
6023 ftrace_graph_hash = hash;
6025 ftrace_graph_notrace_hash = hash;
6027 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6030 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
6034 ftrace_ops_init(ops);
6037 func = strsep(&buf, ",");
6038 ftrace_set_regex(ops, func, strlen(func), 0, enable);
6042 static void __init set_ftrace_early_filters(void)
6044 if (ftrace_filter_buf[0])
6045 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
6046 if (ftrace_notrace_buf[0])
6047 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
6048 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
6049 if (ftrace_graph_buf[0])
6050 set_ftrace_early_graph(ftrace_graph_buf, 1);
6051 if (ftrace_graph_notrace_buf[0])
6052 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
6053 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6056 int ftrace_regex_release(struct inode *inode, struct file *file)
6058 struct seq_file *m = (struct seq_file *)file->private_data;
6059 struct ftrace_iterator *iter;
6060 struct ftrace_hash **orig_hash;
6061 struct trace_parser *parser;
6064 if (file->f_mode & FMODE_READ) {
6066 seq_release(inode, file);
6068 iter = file->private_data;
6070 parser = &iter->parser;
6071 if (trace_parser_loaded(parser)) {
6072 int enable = !(iter->flags & FTRACE_ITER_NOTRACE);
6074 ftrace_process_regex(iter, parser->buffer,
6075 parser->idx, enable);
6078 trace_parser_put(parser);
6080 mutex_lock(&iter->ops->func_hash->regex_lock);
6082 if (file->f_mode & FMODE_WRITE) {
6083 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
6086 orig_hash = &iter->ops->func_hash->filter_hash;
6088 if (list_empty(&iter->tr->mod_trace))
6089 iter->hash->flags &= ~FTRACE_HASH_FL_MOD;
6091 iter->hash->flags |= FTRACE_HASH_FL_MOD;
6094 orig_hash = &iter->ops->func_hash->notrace_hash;
6096 mutex_lock(&ftrace_lock);
6097 ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
6098 iter->hash, filter_hash);
6099 mutex_unlock(&ftrace_lock);
6101 /* For read only, the hash is the ops hash */
6105 mutex_unlock(&iter->ops->func_hash->regex_lock);
6106 free_ftrace_hash(iter->hash);
6108 trace_array_put(iter->tr);
6114 static const struct file_operations ftrace_avail_fops = {
6115 .open = ftrace_avail_open,
6117 .llseek = seq_lseek,
6118 .release = seq_release_private,
6121 static const struct file_operations ftrace_enabled_fops = {
6122 .open = ftrace_enabled_open,
6124 .llseek = seq_lseek,
6125 .release = seq_release_private,
6128 static const struct file_operations ftrace_filter_fops = {
6129 .open = ftrace_filter_open,
6131 .write = ftrace_filter_write,
6132 .llseek = tracing_lseek,
6133 .release = ftrace_regex_release,
6136 static const struct file_operations ftrace_notrace_fops = {
6137 .open = ftrace_notrace_open,
6139 .write = ftrace_notrace_write,
6140 .llseek = tracing_lseek,
6141 .release = ftrace_regex_release,
6144 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
6146 static DEFINE_MUTEX(graph_lock);
6148 struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
6149 struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
6151 enum graph_filter_type {
6152 GRAPH_FILTER_NOTRACE = 0,
6153 GRAPH_FILTER_FUNCTION,
6156 #define FTRACE_GRAPH_EMPTY ((void *)1)
6158 struct ftrace_graph_data {
6159 struct ftrace_hash *hash;
6160 struct ftrace_func_entry *entry;
6161 int idx; /* for hash table iteration */
6162 enum graph_filter_type type;
6163 struct ftrace_hash *new_hash;
6164 const struct seq_operations *seq_ops;
6165 struct trace_parser parser;
6169 __g_next(struct seq_file *m, loff_t *pos)
6171 struct ftrace_graph_data *fgd = m->private;
6172 struct ftrace_func_entry *entry = fgd->entry;
6173 struct hlist_head *head;
6174 int i, idx = fgd->idx;
6176 if (*pos >= fgd->hash->count)
6180 hlist_for_each_entry_continue(entry, hlist) {
6188 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
6189 head = &fgd->hash->buckets[i];
6190 hlist_for_each_entry(entry, head, hlist) {
6200 g_next(struct seq_file *m, void *v, loff_t *pos)
6203 return __g_next(m, pos);
6206 static void *g_start(struct seq_file *m, loff_t *pos)
6208 struct ftrace_graph_data *fgd = m->private;
6210 mutex_lock(&graph_lock);
6212 if (fgd->type == GRAPH_FILTER_FUNCTION)
6213 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6214 lockdep_is_held(&graph_lock));
6216 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6217 lockdep_is_held(&graph_lock));
6219 /* Nothing, tell g_show to print all functions are enabled */
6220 if (ftrace_hash_empty(fgd->hash) && !*pos)
6221 return FTRACE_GRAPH_EMPTY;
6225 return __g_next(m, pos);
6228 static void g_stop(struct seq_file *m, void *p)
6230 mutex_unlock(&graph_lock);
6233 static int g_show(struct seq_file *m, void *v)
6235 struct ftrace_func_entry *entry = v;
6240 if (entry == FTRACE_GRAPH_EMPTY) {
6241 struct ftrace_graph_data *fgd = m->private;
6243 if (fgd->type == GRAPH_FILTER_FUNCTION)
6244 seq_puts(m, "#### all functions enabled ####\n");
6246 seq_puts(m, "#### no functions disabled ####\n");
6250 seq_printf(m, "%ps\n", (void *)entry->ip);
6255 static const struct seq_operations ftrace_graph_seq_ops = {
6263 __ftrace_graph_open(struct inode *inode, struct file *file,
6264 struct ftrace_graph_data *fgd)
6267 struct ftrace_hash *new_hash = NULL;
6269 ret = security_locked_down(LOCKDOWN_TRACEFS);
6273 if (file->f_mode & FMODE_WRITE) {
6274 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
6276 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
6279 if (file->f_flags & O_TRUNC)
6280 new_hash = alloc_ftrace_hash(size_bits);
6282 new_hash = alloc_and_copy_ftrace_hash(size_bits,
6290 if (file->f_mode & FMODE_READ) {
6291 ret = seq_open(file, &ftrace_graph_seq_ops);
6293 struct seq_file *m = file->private_data;
6297 free_ftrace_hash(new_hash);
6301 file->private_data = fgd;
6304 if (ret < 0 && file->f_mode & FMODE_WRITE)
6305 trace_parser_put(&fgd->parser);
6307 fgd->new_hash = new_hash;
6310 * All uses of fgd->hash must be taken with the graph_lock
6311 * held. The graph_lock is going to be released, so force
6312 * fgd->hash to be reinitialized when it is taken again.
6320 ftrace_graph_open(struct inode *inode, struct file *file)
6322 struct ftrace_graph_data *fgd;
6325 if (unlikely(ftrace_disabled))
6328 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6332 mutex_lock(&graph_lock);
6334 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6335 lockdep_is_held(&graph_lock));
6336 fgd->type = GRAPH_FILTER_FUNCTION;
6337 fgd->seq_ops = &ftrace_graph_seq_ops;
6339 ret = __ftrace_graph_open(inode, file, fgd);
6343 mutex_unlock(&graph_lock);
6348 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
6350 struct ftrace_graph_data *fgd;
6353 if (unlikely(ftrace_disabled))
6356 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6360 mutex_lock(&graph_lock);
6362 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6363 lockdep_is_held(&graph_lock));
6364 fgd->type = GRAPH_FILTER_NOTRACE;
6365 fgd->seq_ops = &ftrace_graph_seq_ops;
6367 ret = __ftrace_graph_open(inode, file, fgd);
6371 mutex_unlock(&graph_lock);
6376 ftrace_graph_release(struct inode *inode, struct file *file)
6378 struct ftrace_graph_data *fgd;
6379 struct ftrace_hash *old_hash, *new_hash;
6380 struct trace_parser *parser;
6383 if (file->f_mode & FMODE_READ) {
6384 struct seq_file *m = file->private_data;
6387 seq_release(inode, file);
6389 fgd = file->private_data;
6393 if (file->f_mode & FMODE_WRITE) {
6395 parser = &fgd->parser;
6397 if (trace_parser_loaded((parser))) {
6398 ret = ftrace_graph_set_hash(fgd->new_hash,
6402 trace_parser_put(parser);
6404 new_hash = __ftrace_hash_move(fgd->new_hash);
6410 mutex_lock(&graph_lock);
6412 if (fgd->type == GRAPH_FILTER_FUNCTION) {
6413 old_hash = rcu_dereference_protected(ftrace_graph_hash,
6414 lockdep_is_held(&graph_lock));
6415 rcu_assign_pointer(ftrace_graph_hash, new_hash);
6417 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6418 lockdep_is_held(&graph_lock));
6419 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
6422 mutex_unlock(&graph_lock);
6425 * We need to do a hard force of sched synchronization.
6426 * This is because we use preempt_disable() to do RCU, but
6427 * the function tracers can be called where RCU is not watching
6428 * (like before user_exit()). We can not rely on the RCU
6429 * infrastructure to do the synchronization, thus we must do it
6432 if (old_hash != EMPTY_HASH)
6433 synchronize_rcu_tasks_rude();
6435 free_ftrace_hash(old_hash);
6439 free_ftrace_hash(fgd->new_hash);
6446 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
6448 struct ftrace_glob func_g;
6449 struct dyn_ftrace *rec;
6450 struct ftrace_page *pg;
6451 struct ftrace_func_entry *entry;
6456 func_g.type = filter_parse_regex(buffer, strlen(buffer),
6457 &func_g.search, ¬);
6459 func_g.len = strlen(func_g.search);
6461 mutex_lock(&ftrace_lock);
6463 if (unlikely(ftrace_disabled)) {
6464 mutex_unlock(&ftrace_lock);
6468 do_for_each_ftrace_rec(pg, rec) {
6470 if (rec->flags & FTRACE_FL_DISABLED)
6473 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
6474 entry = ftrace_lookup_ip(hash, rec->ip);
6481 if (add_hash_entry(hash, rec->ip) < 0)
6485 free_hash_entry(hash, entry);
6490 } while_for_each_ftrace_rec();
6492 mutex_unlock(&ftrace_lock);
6501 ftrace_graph_write(struct file *file, const char __user *ubuf,
6502 size_t cnt, loff_t *ppos)
6504 ssize_t read, ret = 0;
6505 struct ftrace_graph_data *fgd = file->private_data;
6506 struct trace_parser *parser;
6511 /* Read mode uses seq functions */
6512 if (file->f_mode & FMODE_READ) {
6513 struct seq_file *m = file->private_data;
6517 parser = &fgd->parser;
6519 read = trace_get_user(parser, ubuf, cnt, ppos);
6521 if (read >= 0 && trace_parser_loaded(parser) &&
6522 !trace_parser_cont(parser)) {
6524 ret = ftrace_graph_set_hash(fgd->new_hash,
6526 trace_parser_clear(parser);
6535 static const struct file_operations ftrace_graph_fops = {
6536 .open = ftrace_graph_open,
6538 .write = ftrace_graph_write,
6539 .llseek = tracing_lseek,
6540 .release = ftrace_graph_release,
6543 static const struct file_operations ftrace_graph_notrace_fops = {
6544 .open = ftrace_graph_notrace_open,
6546 .write = ftrace_graph_write,
6547 .llseek = tracing_lseek,
6548 .release = ftrace_graph_release,
6550 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6552 void ftrace_create_filter_files(struct ftrace_ops *ops,
6553 struct dentry *parent)
6556 trace_create_file("set_ftrace_filter", TRACE_MODE_WRITE, parent,
6557 ops, &ftrace_filter_fops);
6559 trace_create_file("set_ftrace_notrace", TRACE_MODE_WRITE, parent,
6560 ops, &ftrace_notrace_fops);
6564 * The name "destroy_filter_files" is really a misnomer. Although
6565 * in the future, it may actually delete the files, but this is
6566 * really intended to make sure the ops passed in are disabled
6567 * and that when this function returns, the caller is free to
6570 * The "destroy" name is only to match the "create" name that this
6571 * should be paired with.
6573 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
6575 mutex_lock(&ftrace_lock);
6576 if (ops->flags & FTRACE_OPS_FL_ENABLED)
6577 ftrace_shutdown(ops, 0);
6578 ops->flags |= FTRACE_OPS_FL_DELETED;
6579 ftrace_free_filter(ops);
6580 mutex_unlock(&ftrace_lock);
6583 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
6586 trace_create_file("available_filter_functions", TRACE_MODE_READ,
6587 d_tracer, NULL, &ftrace_avail_fops);
6589 trace_create_file("enabled_functions", TRACE_MODE_READ,
6590 d_tracer, NULL, &ftrace_enabled_fops);
6592 ftrace_create_filter_files(&global_ops, d_tracer);
6594 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
6595 trace_create_file("set_graph_function", TRACE_MODE_WRITE, d_tracer,
6597 &ftrace_graph_fops);
6598 trace_create_file("set_graph_notrace", TRACE_MODE_WRITE, d_tracer,
6600 &ftrace_graph_notrace_fops);
6601 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6606 static int ftrace_cmp_ips(const void *a, const void *b)
6608 const unsigned long *ipa = a;
6609 const unsigned long *ipb = b;
6618 #ifdef CONFIG_FTRACE_SORT_STARTUP_TEST
6619 static void test_is_sorted(unsigned long *start, unsigned long count)
6623 for (i = 1; i < count; i++) {
6624 if (WARN(start[i - 1] > start[i],
6625 "[%d] %pS at %lx is not sorted with %pS at %lx\n", i,
6626 (void *)start[i - 1], start[i - 1],
6627 (void *)start[i], start[i]))
6631 pr_info("ftrace section at %px sorted properly\n", start);
6634 static void test_is_sorted(unsigned long *start, unsigned long count)
6639 static int ftrace_process_locs(struct module *mod,
6640 unsigned long *start,
6643 struct ftrace_page *start_pg;
6644 struct ftrace_page *pg;
6645 struct dyn_ftrace *rec;
6646 unsigned long count;
6649 unsigned long flags = 0; /* Shut up gcc */
6652 count = end - start;
6658 * Sorting mcount in vmlinux at build time depend on
6659 * CONFIG_BUILDTIME_MCOUNT_SORT, while mcount loc in
6660 * modules can not be sorted at build time.
6662 if (!IS_ENABLED(CONFIG_BUILDTIME_MCOUNT_SORT) || mod) {
6663 sort(start, count, sizeof(*start),
6664 ftrace_cmp_ips, NULL);
6666 test_is_sorted(start, count);
6669 start_pg = ftrace_allocate_pages(count);
6673 mutex_lock(&ftrace_lock);
6676 * Core and each module needs their own pages, as
6677 * modules will free them when they are removed.
6678 * Force a new page to be allocated for modules.
6681 WARN_ON(ftrace_pages || ftrace_pages_start);
6682 /* First initialization */
6683 ftrace_pages = ftrace_pages_start = start_pg;
6688 if (WARN_ON(ftrace_pages->next)) {
6689 /* Hmm, we have free pages? */
6690 while (ftrace_pages->next)
6691 ftrace_pages = ftrace_pages->next;
6694 ftrace_pages->next = start_pg;
6700 unsigned long end_offset;
6701 addr = ftrace_call_adjust(*p++);
6703 * Some architecture linkers will pad between
6704 * the different mcount_loc sections of different
6705 * object files to satisfy alignments.
6706 * Skip any NULL pointers.
6711 end_offset = (pg->index+1) * sizeof(pg->records[0]);
6712 if (end_offset > PAGE_SIZE << pg->order) {
6713 /* We should have allocated enough */
6714 if (WARN_ON(!pg->next))
6719 rec = &pg->records[pg->index++];
6723 /* We should have used all pages */
6726 /* Assign the last page to ftrace_pages */
6730 * We only need to disable interrupts on start up
6731 * because we are modifying code that an interrupt
6732 * may execute, and the modification is not atomic.
6733 * But for modules, nothing runs the code we modify
6734 * until we are finished with it, and there's no
6735 * reason to cause large interrupt latencies while we do it.
6738 local_irq_save(flags);
6739 ftrace_update_code(mod, start_pg);
6741 local_irq_restore(flags);
6744 mutex_unlock(&ftrace_lock);
6749 struct ftrace_mod_func {
6750 struct list_head list;
6756 struct ftrace_mod_map {
6757 struct rcu_head rcu;
6758 struct list_head list;
6760 unsigned long start_addr;
6761 unsigned long end_addr;
6762 struct list_head funcs;
6763 unsigned int num_funcs;
6766 static int ftrace_get_trampoline_kallsym(unsigned int symnum,
6767 unsigned long *value, char *type,
6768 char *name, char *module_name,
6771 struct ftrace_ops *op;
6773 list_for_each_entry_rcu(op, &ftrace_ops_trampoline_list, list) {
6774 if (!op->trampoline || symnum--)
6776 *value = op->trampoline;
6778 strlcpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
6779 strlcpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
6787 #if defined(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS) || defined(CONFIG_MODULES)
6789 * Check if the current ops references the given ip.
6791 * If the ops traces all functions, then it was already accounted for.
6792 * If the ops does not trace the current record function, skip it.
6793 * If the ops ignores the function via notrace filter, skip it.
6796 ops_references_ip(struct ftrace_ops *ops, unsigned long ip)
6798 /* If ops isn't enabled, ignore it */
6799 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
6802 /* If ops traces all then it includes this function */
6803 if (ops_traces_mod(ops))
6806 /* The function must be in the filter */
6807 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
6808 !__ftrace_lookup_ip(ops->func_hash->filter_hash, ip))
6811 /* If in notrace hash, we ignore it too */
6812 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, ip))
6819 #ifdef CONFIG_MODULES
6821 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
6823 static LIST_HEAD(ftrace_mod_maps);
6825 static int referenced_filters(struct dyn_ftrace *rec)
6827 struct ftrace_ops *ops;
6830 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
6831 if (ops_references_ip(ops, rec->ip)) {
6832 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_DIRECT))
6834 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_IPMODIFY))
6837 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
6838 rec->flags |= FTRACE_FL_REGS;
6839 if (cnt == 1 && ops->trampoline)
6840 rec->flags |= FTRACE_FL_TRAMP;
6842 rec->flags &= ~FTRACE_FL_TRAMP;
6850 clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
6852 struct ftrace_func_entry *entry;
6853 struct dyn_ftrace *rec;
6856 if (ftrace_hash_empty(hash))
6859 for (i = 0; i < pg->index; i++) {
6860 rec = &pg->records[i];
6861 entry = __ftrace_lookup_ip(hash, rec->ip);
6863 * Do not allow this rec to match again.
6864 * Yeah, it may waste some memory, but will be removed
6865 * if/when the hash is modified again.
6872 /* Clear any records from hashes */
6873 static void clear_mod_from_hashes(struct ftrace_page *pg)
6875 struct trace_array *tr;
6877 mutex_lock(&trace_types_lock);
6878 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6879 if (!tr->ops || !tr->ops->func_hash)
6881 mutex_lock(&tr->ops->func_hash->regex_lock);
6882 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
6883 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
6884 mutex_unlock(&tr->ops->func_hash->regex_lock);
6886 mutex_unlock(&trace_types_lock);
6889 static void ftrace_free_mod_map(struct rcu_head *rcu)
6891 struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
6892 struct ftrace_mod_func *mod_func;
6893 struct ftrace_mod_func *n;
6895 /* All the contents of mod_map are now not visible to readers */
6896 list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
6897 kfree(mod_func->name);
6898 list_del(&mod_func->list);
6905 void ftrace_release_mod(struct module *mod)
6907 struct ftrace_mod_map *mod_map;
6908 struct ftrace_mod_map *n;
6909 struct dyn_ftrace *rec;
6910 struct ftrace_page **last_pg;
6911 struct ftrace_page *tmp_page = NULL;
6912 struct ftrace_page *pg;
6914 mutex_lock(&ftrace_lock);
6916 if (ftrace_disabled)
6919 list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
6920 if (mod_map->mod == mod) {
6921 list_del_rcu(&mod_map->list);
6922 call_rcu(&mod_map->rcu, ftrace_free_mod_map);
6928 * Each module has its own ftrace_pages, remove
6929 * them from the list.
6931 last_pg = &ftrace_pages_start;
6932 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
6933 rec = &pg->records[0];
6934 if (within_module_core(rec->ip, mod) ||
6935 within_module_init(rec->ip, mod)) {
6937 * As core pages are first, the first
6938 * page should never be a module page.
6940 if (WARN_ON(pg == ftrace_pages_start))
6943 /* Check if we are deleting the last page */
6944 if (pg == ftrace_pages)
6945 ftrace_pages = next_to_ftrace_page(last_pg);
6947 ftrace_update_tot_cnt -= pg->index;
6948 *last_pg = pg->next;
6950 pg->next = tmp_page;
6953 last_pg = &pg->next;
6956 mutex_unlock(&ftrace_lock);
6958 for (pg = tmp_page; pg; pg = tmp_page) {
6960 /* Needs to be called outside of ftrace_lock */
6961 clear_mod_from_hashes(pg);
6964 free_pages((unsigned long)pg->records, pg->order);
6965 ftrace_number_of_pages -= 1 << pg->order;
6967 tmp_page = pg->next;
6969 ftrace_number_of_groups--;
6973 void ftrace_module_enable(struct module *mod)
6975 struct dyn_ftrace *rec;
6976 struct ftrace_page *pg;
6978 mutex_lock(&ftrace_lock);
6980 if (ftrace_disabled)
6984 * If the tracing is enabled, go ahead and enable the record.
6986 * The reason not to enable the record immediately is the
6987 * inherent check of ftrace_make_nop/ftrace_make_call for
6988 * correct previous instructions. Making first the NOP
6989 * conversion puts the module to the correct state, thus
6990 * passing the ftrace_make_call check.
6992 * We also delay this to after the module code already set the
6993 * text to read-only, as we now need to set it back to read-write
6994 * so that we can modify the text.
6996 if (ftrace_start_up)
6997 ftrace_arch_code_modify_prepare();
6999 do_for_each_ftrace_rec(pg, rec) {
7002 * do_for_each_ftrace_rec() is a double loop.
7003 * module text shares the pg. If a record is
7004 * not part of this module, then skip this pg,
7005 * which the "break" will do.
7007 if (!within_module_core(rec->ip, mod) &&
7008 !within_module_init(rec->ip, mod))
7011 /* Weak functions should still be ignored */
7012 if (!test_for_valid_rec(rec)) {
7013 /* Clear all other flags. Should not be enabled anyway */
7014 rec->flags = FTRACE_FL_DISABLED;
7021 * When adding a module, we need to check if tracers are
7022 * currently enabled and if they are, and can trace this record,
7023 * we need to enable the module functions as well as update the
7024 * reference counts for those function records.
7026 if (ftrace_start_up)
7027 cnt += referenced_filters(rec);
7029 rec->flags &= ~FTRACE_FL_DISABLED;
7032 if (ftrace_start_up && cnt) {
7033 int failed = __ftrace_replace_code(rec, 1);
7035 ftrace_bug(failed, rec);
7040 } while_for_each_ftrace_rec();
7043 if (ftrace_start_up)
7044 ftrace_arch_code_modify_post_process();
7047 mutex_unlock(&ftrace_lock);
7049 process_cached_mods(mod->name);
7052 void ftrace_module_init(struct module *mod)
7056 if (ftrace_disabled || !mod->num_ftrace_callsites)
7059 ret = ftrace_process_locs(mod, mod->ftrace_callsites,
7060 mod->ftrace_callsites + mod->num_ftrace_callsites);
7062 pr_warn("ftrace: failed to allocate entries for module '%s' functions\n",
7066 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
7067 struct dyn_ftrace *rec)
7069 struct ftrace_mod_func *mod_func;
7070 unsigned long symsize;
7071 unsigned long offset;
7072 char str[KSYM_SYMBOL_LEN];
7076 ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
7080 mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
7084 mod_func->name = kstrdup(str, GFP_KERNEL);
7085 if (!mod_func->name) {
7090 mod_func->ip = rec->ip - offset;
7091 mod_func->size = symsize;
7093 mod_map->num_funcs++;
7095 list_add_rcu(&mod_func->list, &mod_map->funcs);
7098 static struct ftrace_mod_map *
7099 allocate_ftrace_mod_map(struct module *mod,
7100 unsigned long start, unsigned long end)
7102 struct ftrace_mod_map *mod_map;
7104 mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
7109 mod_map->start_addr = start;
7110 mod_map->end_addr = end;
7111 mod_map->num_funcs = 0;
7113 INIT_LIST_HEAD_RCU(&mod_map->funcs);
7115 list_add_rcu(&mod_map->list, &ftrace_mod_maps);
7121 ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
7122 unsigned long addr, unsigned long *size,
7123 unsigned long *off, char *sym)
7125 struct ftrace_mod_func *found_func = NULL;
7126 struct ftrace_mod_func *mod_func;
7128 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
7129 if (addr >= mod_func->ip &&
7130 addr < mod_func->ip + mod_func->size) {
7131 found_func = mod_func;
7138 *size = found_func->size;
7140 *off = addr - found_func->ip;
7142 strlcpy(sym, found_func->name, KSYM_NAME_LEN);
7144 return found_func->name;
7151 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
7152 unsigned long *off, char **modname, char *sym)
7154 struct ftrace_mod_map *mod_map;
7155 const char *ret = NULL;
7157 /* mod_map is freed via call_rcu() */
7159 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
7160 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
7163 *modname = mod_map->mod->name;
7172 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7173 char *type, char *name,
7174 char *module_name, int *exported)
7176 struct ftrace_mod_map *mod_map;
7177 struct ftrace_mod_func *mod_func;
7181 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
7183 if (symnum >= mod_map->num_funcs) {
7184 symnum -= mod_map->num_funcs;
7188 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
7194 *value = mod_func->ip;
7196 strlcpy(name, mod_func->name, KSYM_NAME_LEN);
7197 strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
7205 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7206 module_name, exported);
7212 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
7213 struct dyn_ftrace *rec) { }
7214 static inline struct ftrace_mod_map *
7215 allocate_ftrace_mod_map(struct module *mod,
7216 unsigned long start, unsigned long end)
7220 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7221 char *type, char *name, char *module_name,
7227 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7228 module_name, exported);
7232 #endif /* CONFIG_MODULES */
7234 struct ftrace_init_func {
7235 struct list_head list;
7239 /* Clear any init ips from hashes */
7241 clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
7243 struct ftrace_func_entry *entry;
7245 entry = ftrace_lookup_ip(hash, func->ip);
7247 * Do not allow this rec to match again.
7248 * Yeah, it may waste some memory, but will be removed
7249 * if/when the hash is modified again.
7256 clear_func_from_hashes(struct ftrace_init_func *func)
7258 struct trace_array *tr;
7260 mutex_lock(&trace_types_lock);
7261 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
7262 if (!tr->ops || !tr->ops->func_hash)
7264 mutex_lock(&tr->ops->func_hash->regex_lock);
7265 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
7266 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
7267 mutex_unlock(&tr->ops->func_hash->regex_lock);
7269 mutex_unlock(&trace_types_lock);
7272 static void add_to_clear_hash_list(struct list_head *clear_list,
7273 struct dyn_ftrace *rec)
7275 struct ftrace_init_func *func;
7277 func = kmalloc(sizeof(*func), GFP_KERNEL);
7279 MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
7284 list_add(&func->list, clear_list);
7287 void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
7289 unsigned long start = (unsigned long)(start_ptr);
7290 unsigned long end = (unsigned long)(end_ptr);
7291 struct ftrace_page **last_pg = &ftrace_pages_start;
7292 struct ftrace_page *pg;
7293 struct dyn_ftrace *rec;
7294 struct dyn_ftrace key;
7295 struct ftrace_mod_map *mod_map = NULL;
7296 struct ftrace_init_func *func, *func_next;
7297 struct list_head clear_hash;
7299 INIT_LIST_HEAD(&clear_hash);
7302 key.flags = end; /* overload flags, as it is unsigned long */
7304 mutex_lock(&ftrace_lock);
7307 * If we are freeing module init memory, then check if
7308 * any tracer is active. If so, we need to save a mapping of
7309 * the module functions being freed with the address.
7311 if (mod && ftrace_ops_list != &ftrace_list_end)
7312 mod_map = allocate_ftrace_mod_map(mod, start, end);
7314 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
7315 if (end < pg->records[0].ip ||
7316 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
7319 rec = bsearch(&key, pg->records, pg->index,
7320 sizeof(struct dyn_ftrace),
7325 /* rec will be cleared from hashes after ftrace_lock unlock */
7326 add_to_clear_hash_list(&clear_hash, rec);
7329 save_ftrace_mod_rec(mod_map, rec);
7332 ftrace_update_tot_cnt--;
7334 *last_pg = pg->next;
7336 free_pages((unsigned long)pg->records, pg->order);
7337 ftrace_number_of_pages -= 1 << pg->order;
7339 ftrace_number_of_groups--;
7341 pg = container_of(last_pg, struct ftrace_page, next);
7346 memmove(rec, rec + 1,
7347 (pg->index - (rec - pg->records)) * sizeof(*rec));
7348 /* More than one function may be in this block */
7351 mutex_unlock(&ftrace_lock);
7353 list_for_each_entry_safe(func, func_next, &clear_hash, list) {
7354 clear_func_from_hashes(func);
7359 void __init ftrace_free_init_mem(void)
7361 void *start = (void *)(&__init_begin);
7362 void *end = (void *)(&__init_end);
7364 ftrace_boot_snapshot();
7366 ftrace_free_mem(NULL, start, end);
7369 int __init __weak ftrace_dyn_arch_init(void)
7374 void __init ftrace_init(void)
7376 extern unsigned long __start_mcount_loc[];
7377 extern unsigned long __stop_mcount_loc[];
7378 unsigned long count, flags;
7381 local_irq_save(flags);
7382 ret = ftrace_dyn_arch_init();
7383 local_irq_restore(flags);
7387 count = __stop_mcount_loc - __start_mcount_loc;
7389 pr_info("ftrace: No functions to be traced?\n");
7393 pr_info("ftrace: allocating %ld entries in %ld pages\n",
7394 count, count / ENTRIES_PER_PAGE + 1);
7396 ret = ftrace_process_locs(NULL,
7400 pr_warn("ftrace: failed to allocate entries for functions\n");
7404 pr_info("ftrace: allocated %ld pages with %ld groups\n",
7405 ftrace_number_of_pages, ftrace_number_of_groups);
7407 last_ftrace_enabled = ftrace_enabled = 1;
7409 set_ftrace_early_filters();
7413 ftrace_disabled = 1;
7416 /* Do nothing if arch does not support this */
7417 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
7421 static void ftrace_update_trampoline(struct ftrace_ops *ops)
7423 unsigned long trampoline = ops->trampoline;
7425 arch_ftrace_update_trampoline(ops);
7426 if (ops->trampoline && ops->trampoline != trampoline &&
7427 (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) {
7428 /* Add to kallsyms before the perf events */
7429 ftrace_add_trampoline_to_kallsyms(ops);
7430 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
7431 ops->trampoline, ops->trampoline_size, false,
7432 FTRACE_TRAMPOLINE_SYM);
7434 * Record the perf text poke event after the ksymbol register
7437 perf_event_text_poke((void *)ops->trampoline, NULL, 0,
7438 (void *)ops->trampoline,
7439 ops->trampoline_size);
7443 void ftrace_init_trace_array(struct trace_array *tr)
7445 INIT_LIST_HEAD(&tr->func_probes);
7446 INIT_LIST_HEAD(&tr->mod_trace);
7447 INIT_LIST_HEAD(&tr->mod_notrace);
7451 struct ftrace_ops global_ops = {
7452 .func = ftrace_stub,
7453 .flags = FTRACE_OPS_FL_INITIALIZED |
7457 static int __init ftrace_nodyn_init(void)
7462 core_initcall(ftrace_nodyn_init);
7464 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
7465 static inline void ftrace_startup_all(int command) { }
7467 static void ftrace_update_trampoline(struct ftrace_ops *ops)
7471 #endif /* CONFIG_DYNAMIC_FTRACE */
7473 __init void ftrace_init_global_array_ops(struct trace_array *tr)
7475 tr->ops = &global_ops;
7476 tr->ops->private = tr;
7477 ftrace_init_trace_array(tr);
7480 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
7482 /* If we filter on pids, update to use the pid function */
7483 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
7484 if (WARN_ON(tr->ops->func != ftrace_stub))
7485 printk("ftrace ops had %pS for function\n",
7488 tr->ops->func = func;
7489 tr->ops->private = tr;
7492 void ftrace_reset_array_ops(struct trace_array *tr)
7494 tr->ops->func = ftrace_stub;
7497 static nokprobe_inline void
7498 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7499 struct ftrace_ops *ignored, struct ftrace_regs *fregs)
7501 struct pt_regs *regs = ftrace_get_regs(fregs);
7502 struct ftrace_ops *op;
7506 * The ftrace_test_and_set_recursion() will disable preemption,
7507 * which is required since some of the ops may be dynamically
7508 * allocated, they must be freed after a synchronize_rcu().
7510 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7514 do_for_each_ftrace_op(op, ftrace_ops_list) {
7515 /* Stub functions don't need to be called nor tested */
7516 if (op->flags & FTRACE_OPS_FL_STUB)
7519 * Check the following for each ops before calling their func:
7520 * if RCU flag is set, then rcu_is_watching() must be true
7521 * if PER_CPU is set, then ftrace_function_local_disable()
7523 * Otherwise test if the ip matches the ops filter
7525 * If any of the above fails then the op->func() is not executed.
7527 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
7528 ftrace_ops_test(op, ip, regs)) {
7529 if (FTRACE_WARN_ON(!op->func)) {
7530 pr_warn("op=%p %pS\n", op, op);
7533 op->func(ip, parent_ip, op, fregs);
7535 } while_for_each_ftrace_op(op);
7537 trace_clear_recursion(bit);
7541 * Some archs only support passing ip and parent_ip. Even though
7542 * the list function ignores the op parameter, we do not want any
7543 * C side effects, where a function is called without the caller
7544 * sending a third parameter.
7545 * Archs are to support both the regs and ftrace_ops at the same time.
7546 * If they support ftrace_ops, it is assumed they support regs.
7547 * If call backs want to use regs, they must either check for regs
7548 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
7549 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
7550 * An architecture can pass partial regs with ftrace_ops and still
7551 * set the ARCH_SUPPORTS_FTRACE_OPS.
7553 * In vmlinux.lds.h, ftrace_ops_list_func() is defined to be
7554 * arch_ftrace_ops_list_func.
7556 #if ARCH_SUPPORTS_FTRACE_OPS
7557 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7558 struct ftrace_ops *op, struct ftrace_regs *fregs)
7560 __ftrace_ops_list_func(ip, parent_ip, NULL, fregs);
7563 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
7565 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
7568 NOKPROBE_SYMBOL(arch_ftrace_ops_list_func);
7571 * If there's only one function registered but it does not support
7572 * recursion, needs RCU protection and/or requires per cpu handling, then
7573 * this function will be called by the mcount trampoline.
7575 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
7576 struct ftrace_ops *op, struct ftrace_regs *fregs)
7580 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7584 if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
7585 op->func(ip, parent_ip, op, fregs);
7587 trace_clear_recursion(bit);
7589 NOKPROBE_SYMBOL(ftrace_ops_assist_func);
7592 * ftrace_ops_get_func - get the function a trampoline should call
7593 * @ops: the ops to get the function for
7595 * Normally the mcount trampoline will call the ops->func, but there
7596 * are times that it should not. For example, if the ops does not
7597 * have its own recursion protection, then it should call the
7598 * ftrace_ops_assist_func() instead.
7600 * Returns the function that the trampoline should call for @ops.
7602 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
7605 * If the function does not handle recursion or needs to be RCU safe,
7606 * then we need to call the assist handler.
7608 if (ops->flags & (FTRACE_OPS_FL_RECURSION |
7610 return ftrace_ops_assist_func;
7616 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
7617 struct task_struct *prev,
7618 struct task_struct *next,
7619 unsigned int prev_state)
7621 struct trace_array *tr = data;
7622 struct trace_pid_list *pid_list;
7623 struct trace_pid_list *no_pid_list;
7625 pid_list = rcu_dereference_sched(tr->function_pids);
7626 no_pid_list = rcu_dereference_sched(tr->function_no_pids);
7628 if (trace_ignore_this_task(pid_list, no_pid_list, next))
7629 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7632 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7637 ftrace_pid_follow_sched_process_fork(void *data,
7638 struct task_struct *self,
7639 struct task_struct *task)
7641 struct trace_pid_list *pid_list;
7642 struct trace_array *tr = data;
7644 pid_list = rcu_dereference_sched(tr->function_pids);
7645 trace_filter_add_remove_task(pid_list, self, task);
7647 pid_list = rcu_dereference_sched(tr->function_no_pids);
7648 trace_filter_add_remove_task(pid_list, self, task);
7652 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
7654 struct trace_pid_list *pid_list;
7655 struct trace_array *tr = data;
7657 pid_list = rcu_dereference_sched(tr->function_pids);
7658 trace_filter_add_remove_task(pid_list, NULL, task);
7660 pid_list = rcu_dereference_sched(tr->function_no_pids);
7661 trace_filter_add_remove_task(pid_list, NULL, task);
7664 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
7667 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7669 register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7672 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7674 unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7679 static void clear_ftrace_pids(struct trace_array *tr, int type)
7681 struct trace_pid_list *pid_list;
7682 struct trace_pid_list *no_pid_list;
7685 pid_list = rcu_dereference_protected(tr->function_pids,
7686 lockdep_is_held(&ftrace_lock));
7687 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7688 lockdep_is_held(&ftrace_lock));
7690 /* Make sure there's something to do */
7691 if (!pid_type_enabled(type, pid_list, no_pid_list))
7694 /* See if the pids still need to be checked after this */
7695 if (!still_need_pid_events(type, pid_list, no_pid_list)) {
7696 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7697 for_each_possible_cpu(cpu)
7698 per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
7701 if (type & TRACE_PIDS)
7702 rcu_assign_pointer(tr->function_pids, NULL);
7704 if (type & TRACE_NO_PIDS)
7705 rcu_assign_pointer(tr->function_no_pids, NULL);
7707 /* Wait till all users are no longer using pid filtering */
7710 if ((type & TRACE_PIDS) && pid_list)
7711 trace_pid_list_free(pid_list);
7713 if ((type & TRACE_NO_PIDS) && no_pid_list)
7714 trace_pid_list_free(no_pid_list);
7717 void ftrace_clear_pids(struct trace_array *tr)
7719 mutex_lock(&ftrace_lock);
7721 clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
7723 mutex_unlock(&ftrace_lock);
7726 static void ftrace_pid_reset(struct trace_array *tr, int type)
7728 mutex_lock(&ftrace_lock);
7729 clear_ftrace_pids(tr, type);
7731 ftrace_update_pid_func();
7732 ftrace_startup_all(0);
7734 mutex_unlock(&ftrace_lock);
7737 /* Greater than any max PID */
7738 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
7740 static void *fpid_start(struct seq_file *m, loff_t *pos)
7743 struct trace_pid_list *pid_list;
7744 struct trace_array *tr = m->private;
7746 mutex_lock(&ftrace_lock);
7747 rcu_read_lock_sched();
7749 pid_list = rcu_dereference_sched(tr->function_pids);
7752 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7754 return trace_pid_start(pid_list, pos);
7757 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
7759 struct trace_array *tr = m->private;
7760 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
7762 if (v == FTRACE_NO_PIDS) {
7766 return trace_pid_next(pid_list, v, pos);
7769 static void fpid_stop(struct seq_file *m, void *p)
7772 rcu_read_unlock_sched();
7773 mutex_unlock(&ftrace_lock);
7776 static int fpid_show(struct seq_file *m, void *v)
7778 if (v == FTRACE_NO_PIDS) {
7779 seq_puts(m, "no pid\n");
7783 return trace_pid_show(m, v);
7786 static const struct seq_operations ftrace_pid_sops = {
7787 .start = fpid_start,
7793 static void *fnpid_start(struct seq_file *m, loff_t *pos)
7796 struct trace_pid_list *pid_list;
7797 struct trace_array *tr = m->private;
7799 mutex_lock(&ftrace_lock);
7800 rcu_read_lock_sched();
7802 pid_list = rcu_dereference_sched(tr->function_no_pids);
7805 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7807 return trace_pid_start(pid_list, pos);
7810 static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
7812 struct trace_array *tr = m->private;
7813 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
7815 if (v == FTRACE_NO_PIDS) {
7819 return trace_pid_next(pid_list, v, pos);
7822 static const struct seq_operations ftrace_no_pid_sops = {
7823 .start = fnpid_start,
7829 static int pid_open(struct inode *inode, struct file *file, int type)
7831 const struct seq_operations *seq_ops;
7832 struct trace_array *tr = inode->i_private;
7836 ret = tracing_check_open_get_tr(tr);
7840 if ((file->f_mode & FMODE_WRITE) &&
7841 (file->f_flags & O_TRUNC))
7842 ftrace_pid_reset(tr, type);
7846 seq_ops = &ftrace_pid_sops;
7849 seq_ops = &ftrace_no_pid_sops;
7852 trace_array_put(tr);
7857 ret = seq_open(file, seq_ops);
7859 trace_array_put(tr);
7861 m = file->private_data;
7862 /* copy tr over to seq ops */
7870 ftrace_pid_open(struct inode *inode, struct file *file)
7872 return pid_open(inode, file, TRACE_PIDS);
7876 ftrace_no_pid_open(struct inode *inode, struct file *file)
7878 return pid_open(inode, file, TRACE_NO_PIDS);
7881 static void ignore_task_cpu(void *data)
7883 struct trace_array *tr = data;
7884 struct trace_pid_list *pid_list;
7885 struct trace_pid_list *no_pid_list;
7888 * This function is called by on_each_cpu() while the
7889 * event_mutex is held.
7891 pid_list = rcu_dereference_protected(tr->function_pids,
7892 mutex_is_locked(&ftrace_lock));
7893 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7894 mutex_is_locked(&ftrace_lock));
7896 if (trace_ignore_this_task(pid_list, no_pid_list, current))
7897 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7900 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7905 pid_write(struct file *filp, const char __user *ubuf,
7906 size_t cnt, loff_t *ppos, int type)
7908 struct seq_file *m = filp->private_data;
7909 struct trace_array *tr = m->private;
7910 struct trace_pid_list *filtered_pids;
7911 struct trace_pid_list *other_pids;
7912 struct trace_pid_list *pid_list;
7918 mutex_lock(&ftrace_lock);
7922 filtered_pids = rcu_dereference_protected(tr->function_pids,
7923 lockdep_is_held(&ftrace_lock));
7924 other_pids = rcu_dereference_protected(tr->function_no_pids,
7925 lockdep_is_held(&ftrace_lock));
7928 filtered_pids = rcu_dereference_protected(tr->function_no_pids,
7929 lockdep_is_held(&ftrace_lock));
7930 other_pids = rcu_dereference_protected(tr->function_pids,
7931 lockdep_is_held(&ftrace_lock));
7939 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
7945 rcu_assign_pointer(tr->function_pids, pid_list);
7948 rcu_assign_pointer(tr->function_no_pids, pid_list);
7953 if (filtered_pids) {
7955 trace_pid_list_free(filtered_pids);
7956 } else if (pid_list && !other_pids) {
7957 /* Register a probe to set whether to ignore the tracing of a task */
7958 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7962 * Ignoring of pids is done at task switch. But we have to
7963 * check for those tasks that are currently running.
7964 * Always do this in case a pid was appended or removed.
7966 on_each_cpu(ignore_task_cpu, tr, 1);
7968 ftrace_update_pid_func();
7969 ftrace_startup_all(0);
7971 mutex_unlock(&ftrace_lock);
7980 ftrace_pid_write(struct file *filp, const char __user *ubuf,
7981 size_t cnt, loff_t *ppos)
7983 return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
7987 ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
7988 size_t cnt, loff_t *ppos)
7990 return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
7994 ftrace_pid_release(struct inode *inode, struct file *file)
7996 struct trace_array *tr = inode->i_private;
7998 trace_array_put(tr);
8000 return seq_release(inode, file);
8003 static const struct file_operations ftrace_pid_fops = {
8004 .open = ftrace_pid_open,
8005 .write = ftrace_pid_write,
8007 .llseek = tracing_lseek,
8008 .release = ftrace_pid_release,
8011 static const struct file_operations ftrace_no_pid_fops = {
8012 .open = ftrace_no_pid_open,
8013 .write = ftrace_no_pid_write,
8015 .llseek = tracing_lseek,
8016 .release = ftrace_pid_release,
8019 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
8021 trace_create_file("set_ftrace_pid", TRACE_MODE_WRITE, d_tracer,
8022 tr, &ftrace_pid_fops);
8023 trace_create_file("set_ftrace_notrace_pid", TRACE_MODE_WRITE,
8024 d_tracer, tr, &ftrace_no_pid_fops);
8027 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
8028 struct dentry *d_tracer)
8030 /* Only the top level directory has the dyn_tracefs and profile */
8031 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
8033 ftrace_init_dyn_tracefs(d_tracer);
8034 ftrace_profile_tracefs(d_tracer);
8038 * ftrace_kill - kill ftrace
8040 * This function should be used by panic code. It stops ftrace
8041 * but in a not so nice way. If you need to simply kill ftrace
8042 * from a non-atomic section, use ftrace_kill.
8044 void ftrace_kill(void)
8046 ftrace_disabled = 1;
8048 ftrace_trace_function = ftrace_stub;
8052 * ftrace_is_dead - Test if ftrace is dead or not.
8054 * Returns 1 if ftrace is "dead", zero otherwise.
8056 int ftrace_is_dead(void)
8058 return ftrace_disabled;
8061 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
8063 * When registering ftrace_ops with IPMODIFY, it is necessary to make sure
8064 * it doesn't conflict with any direct ftrace_ops. If there is existing
8065 * direct ftrace_ops on a kernel function being patched, call
8066 * FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER on it to enable sharing.
8068 * @ops: ftrace_ops being registered.
8072 * Negative on failure.
8074 static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
8076 struct ftrace_func_entry *entry;
8077 struct ftrace_hash *hash;
8078 struct ftrace_ops *op;
8081 lockdep_assert_held_once(&direct_mutex);
8083 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
8086 hash = ops->func_hash->filter_hash;
8087 size = 1 << hash->size_bits;
8088 for (i = 0; i < size; i++) {
8089 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
8090 unsigned long ip = entry->ip;
8091 bool found_op = false;
8093 mutex_lock(&ftrace_lock);
8094 do_for_each_ftrace_op(op, ftrace_ops_list) {
8095 if (!(op->flags & FTRACE_OPS_FL_DIRECT))
8097 if (ops_references_ip(op, ip)) {
8101 } while_for_each_ftrace_op(op);
8102 mutex_unlock(&ftrace_lock);
8108 ret = op->ops_func(op, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER);
8119 * Similar to prepare_direct_functions_for_ipmodify, clean up after ops
8120 * with IPMODIFY is unregistered. The cleanup is optional for most DIRECT
8123 static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
8125 struct ftrace_func_entry *entry;
8126 struct ftrace_hash *hash;
8127 struct ftrace_ops *op;
8130 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
8133 mutex_lock(&direct_mutex);
8135 hash = ops->func_hash->filter_hash;
8136 size = 1 << hash->size_bits;
8137 for (i = 0; i < size; i++) {
8138 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
8139 unsigned long ip = entry->ip;
8140 bool found_op = false;
8142 mutex_lock(&ftrace_lock);
8143 do_for_each_ftrace_op(op, ftrace_ops_list) {
8144 if (!(op->flags & FTRACE_OPS_FL_DIRECT))
8146 if (ops_references_ip(op, ip)) {
8150 } while_for_each_ftrace_op(op);
8151 mutex_unlock(&ftrace_lock);
8153 /* The cleanup is optional, ignore any errors */
8154 if (found_op && op->ops_func)
8155 op->ops_func(op, FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER);
8158 mutex_unlock(&direct_mutex);
8161 #define lock_direct_mutex() mutex_lock(&direct_mutex)
8162 #define unlock_direct_mutex() mutex_unlock(&direct_mutex)
8164 #else /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
8166 static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
8171 static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
8175 #define lock_direct_mutex() do { } while (0)
8176 #define unlock_direct_mutex() do { } while (0)
8178 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
8181 * Similar to register_ftrace_function, except we don't lock direct_mutex.
8183 static int register_ftrace_function_nolock(struct ftrace_ops *ops)
8187 ftrace_ops_init(ops);
8189 mutex_lock(&ftrace_lock);
8191 ret = ftrace_startup(ops, 0);
8193 mutex_unlock(&ftrace_lock);
8199 * register_ftrace_function - register a function for profiling
8200 * @ops: ops structure that holds the function for profiling.
8202 * Register a function to be called by all functions in the
8205 * Note: @ops->func and all the functions it calls must be labeled
8206 * with "notrace", otherwise it will go into a
8209 int register_ftrace_function(struct ftrace_ops *ops)
8213 lock_direct_mutex();
8214 ret = prepare_direct_functions_for_ipmodify(ops);
8218 ret = register_ftrace_function_nolock(ops);
8221 unlock_direct_mutex();
8224 EXPORT_SYMBOL_GPL(register_ftrace_function);
8227 * unregister_ftrace_function - unregister a function for profiling.
8228 * @ops: ops structure that holds the function to unregister
8230 * Unregister a function that was added to be called by ftrace profiling.
8232 int unregister_ftrace_function(struct ftrace_ops *ops)
8236 mutex_lock(&ftrace_lock);
8237 ret = ftrace_shutdown(ops, 0);
8238 mutex_unlock(&ftrace_lock);
8240 cleanup_direct_functions_after_ipmodify(ops);
8243 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
8245 static int symbols_cmp(const void *a, const void *b)
8247 const char **str_a = (const char **) a;
8248 const char **str_b = (const char **) b;
8250 return strcmp(*str_a, *str_b);
8253 struct kallsyms_data {
8254 unsigned long *addrs;
8260 static int kallsyms_callback(void *data, const char *name,
8261 struct module *mod, unsigned long addr)
8263 struct kallsyms_data *args = data;
8267 sym = bsearch(&name, args->syms, args->cnt, sizeof(*args->syms), symbols_cmp);
8271 idx = sym - args->syms;
8272 if (args->addrs[idx])
8275 if (!ftrace_location(addr))
8278 args->addrs[idx] = addr;
8280 return args->found == args->cnt ? 1 : 0;
8284 * ftrace_lookup_symbols - Lookup addresses for array of symbols
8286 * @sorted_syms: array of symbols pointers symbols to resolve,
8287 * must be alphabetically sorted
8288 * @cnt: number of symbols/addresses in @syms/@addrs arrays
8289 * @addrs: array for storing resulting addresses
8291 * This function looks up addresses for array of symbols provided in
8292 * @syms array (must be alphabetically sorted) and stores them in
8293 * @addrs array, which needs to be big enough to store at least @cnt
8296 * This function returns 0 if all provided symbols are found,
8299 int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
8301 struct kallsyms_data args;
8304 memset(addrs, 0, sizeof(*addrs) * cnt);
8306 args.syms = sorted_syms;
8309 err = kallsyms_on_each_symbol(kallsyms_callback, &args);
8312 return args.found == args.cnt ? 0 : -ESRCH;
8315 #ifdef CONFIG_SYSCTL
8317 #ifdef CONFIG_DYNAMIC_FTRACE
8318 static void ftrace_startup_sysctl(void)
8322 if (unlikely(ftrace_disabled))
8325 /* Force update next time */
8326 saved_ftrace_func = NULL;
8327 /* ftrace_start_up is true if we want ftrace running */
8328 if (ftrace_start_up) {
8329 command = FTRACE_UPDATE_CALLS;
8330 if (ftrace_graph_active)
8331 command |= FTRACE_START_FUNC_RET;
8332 ftrace_startup_enable(command);
8336 static void ftrace_shutdown_sysctl(void)
8340 if (unlikely(ftrace_disabled))
8343 /* ftrace_start_up is true if ftrace is running */
8344 if (ftrace_start_up) {
8345 command = FTRACE_DISABLE_CALLS;
8346 if (ftrace_graph_active)
8347 command |= FTRACE_STOP_FUNC_RET;
8348 ftrace_run_update_code(command);
8352 # define ftrace_startup_sysctl() do { } while (0)
8353 # define ftrace_shutdown_sysctl() do { } while (0)
8354 #endif /* CONFIG_DYNAMIC_FTRACE */
8356 static bool is_permanent_ops_registered(void)
8358 struct ftrace_ops *op;
8360 do_for_each_ftrace_op(op, ftrace_ops_list) {
8361 if (op->flags & FTRACE_OPS_FL_PERMANENT)
8363 } while_for_each_ftrace_op(op);
8369 ftrace_enable_sysctl(struct ctl_table *table, int write,
8370 void *buffer, size_t *lenp, loff_t *ppos)
8374 mutex_lock(&ftrace_lock);
8376 if (unlikely(ftrace_disabled))
8379 ret = proc_dointvec(table, write, buffer, lenp, ppos);
8381 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
8384 if (ftrace_enabled) {
8386 /* we are starting ftrace again */
8387 if (rcu_dereference_protected(ftrace_ops_list,
8388 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
8389 update_ftrace_function();
8391 ftrace_startup_sysctl();
8394 if (is_permanent_ops_registered()) {
8395 ftrace_enabled = true;
8400 /* stopping ftrace calls (just send to ftrace_stub) */
8401 ftrace_trace_function = ftrace_stub;
8403 ftrace_shutdown_sysctl();
8406 last_ftrace_enabled = !!ftrace_enabled;
8408 mutex_unlock(&ftrace_lock);
8412 static struct ctl_table ftrace_sysctls[] = {
8414 .procname = "ftrace_enabled",
8415 .data = &ftrace_enabled,
8416 .maxlen = sizeof(int),
8418 .proc_handler = ftrace_enable_sysctl,
8423 static int __init ftrace_sysctl_init(void)
8425 register_sysctl_init("kernel", ftrace_sysctls);
8428 late_initcall(ftrace_sysctl_init);