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 __ftrace_hash_rec_update(struct ftrace_ops *ops,
1651 struct ftrace_hash *hash;
1652 struct ftrace_hash *other_hash;
1653 struct ftrace_page *pg;
1654 struct dyn_ftrace *rec;
1655 bool update = false;
1659 /* Only update if the ops has been registered */
1660 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1664 * In the filter_hash case:
1665 * If the count is zero, we update all records.
1666 * Otherwise we just update the items in the hash.
1668 * In the notrace_hash case:
1669 * We enable the update in the hash.
1670 * As disabling notrace means enabling the tracing,
1671 * and enabling notrace means disabling, the inc variable
1675 hash = ops->func_hash->filter_hash;
1676 other_hash = ops->func_hash->notrace_hash;
1677 if (ftrace_hash_empty(hash))
1681 hash = ops->func_hash->notrace_hash;
1682 other_hash = ops->func_hash->filter_hash;
1684 * If the notrace hash has no items,
1685 * then there's nothing to do.
1687 if (ftrace_hash_empty(hash))
1691 do_for_each_ftrace_rec(pg, rec) {
1692 int in_other_hash = 0;
1696 if (rec->flags & FTRACE_FL_DISABLED)
1701 * Only the filter_hash affects all records.
1702 * Update if the record is not in the notrace hash.
1704 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1707 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1708 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1711 * If filter_hash is set, we want to match all functions
1712 * that are in the hash but not in the other hash.
1714 * If filter_hash is not set, then we are decrementing.
1715 * That means we match anything that is in the hash
1716 * and also in the other_hash. That is, we need to turn
1717 * off functions in the other hash because they are disabled
1720 if (filter_hash && in_hash && !in_other_hash)
1722 else if (!filter_hash && in_hash &&
1723 (in_other_hash || ftrace_hash_empty(other_hash)))
1731 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1734 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1735 rec->flags |= FTRACE_FL_DIRECT;
1738 * If there's only a single callback registered to a
1739 * function, and the ops has a trampoline registered
1740 * for it, then we can call it directly.
1742 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1743 rec->flags |= FTRACE_FL_TRAMP;
1746 * If we are adding another function callback
1747 * to this function, and the previous had a
1748 * custom trampoline in use, then we need to go
1749 * back to the default trampoline.
1751 rec->flags &= ~FTRACE_FL_TRAMP;
1754 * If any ops wants regs saved for this function
1755 * then all ops will get saved regs.
1757 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1758 rec->flags |= FTRACE_FL_REGS;
1760 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1765 * Only the internal direct_ops should have the
1766 * DIRECT flag set. Thus, if it is removing a
1767 * function, then that function should no longer
1770 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1771 rec->flags &= ~FTRACE_FL_DIRECT;
1774 * If the rec had REGS enabled and the ops that is
1775 * being removed had REGS set, then see if there is
1776 * still any ops for this record that wants regs.
1777 * If not, we can stop recording them.
1779 if (ftrace_rec_count(rec) > 0 &&
1780 rec->flags & FTRACE_FL_REGS &&
1781 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1782 if (!test_rec_ops_needs_regs(rec))
1783 rec->flags &= ~FTRACE_FL_REGS;
1787 * The TRAMP needs to be set only if rec count
1788 * is decremented to one, and the ops that is
1789 * left has a trampoline. As TRAMP can only be
1790 * enabled if there is only a single ops attached
1793 if (ftrace_rec_count(rec) == 1 &&
1794 ftrace_find_tramp_ops_any_other(rec, ops))
1795 rec->flags |= FTRACE_FL_TRAMP;
1797 rec->flags &= ~FTRACE_FL_TRAMP;
1800 * flags will be cleared in ftrace_check_record()
1801 * if rec count is zero.
1806 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1807 update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1809 /* Shortcut, if we handled all records, we are done. */
1810 if (!all && count == hash->count)
1812 } while_for_each_ftrace_rec();
1817 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1820 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1823 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1826 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1829 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1830 int filter_hash, int inc)
1832 struct ftrace_ops *op;
1834 __ftrace_hash_rec_update(ops, filter_hash, inc);
1836 if (ops->func_hash != &global_ops.local_hash)
1840 * If the ops shares the global_ops hash, then we need to update
1841 * all ops that are enabled and use this hash.
1843 do_for_each_ftrace_op(op, ftrace_ops_list) {
1847 if (op->func_hash == &global_ops.local_hash)
1848 __ftrace_hash_rec_update(op, filter_hash, inc);
1849 } while_for_each_ftrace_op(op);
1852 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1855 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1858 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1861 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1865 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1866 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1867 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1868 * Note that old_hash and new_hash has below meanings
1869 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1870 * - If the hash is EMPTY_HASH, it hits nothing
1871 * - Anything else hits the recs which match the hash entries.
1873 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1874 struct ftrace_hash *old_hash,
1875 struct ftrace_hash *new_hash)
1877 struct ftrace_page *pg;
1878 struct dyn_ftrace *rec, *end = NULL;
1881 /* Only update if the ops has been registered */
1882 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1885 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1889 * Since the IPMODIFY is a very address sensitive action, we do not
1890 * allow ftrace_ops to set all functions to new hash.
1892 if (!new_hash || !old_hash)
1895 /* Update rec->flags */
1896 do_for_each_ftrace_rec(pg, rec) {
1898 if (rec->flags & FTRACE_FL_DISABLED)
1901 /* We need to update only differences of filter_hash */
1902 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1903 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1904 if (in_old == in_new)
1908 /* New entries must ensure no others are using it */
1909 if (rec->flags & FTRACE_FL_IPMODIFY)
1911 rec->flags |= FTRACE_FL_IPMODIFY;
1912 } else /* Removed entry */
1913 rec->flags &= ~FTRACE_FL_IPMODIFY;
1914 } while_for_each_ftrace_rec();
1921 /* Roll back what we did above */
1922 do_for_each_ftrace_rec(pg, rec) {
1924 if (rec->flags & FTRACE_FL_DISABLED)
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 rec->flags &= ~FTRACE_FL_IPMODIFY;
1938 rec->flags |= FTRACE_FL_IPMODIFY;
1939 } while_for_each_ftrace_rec();
1945 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1947 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1949 if (ftrace_hash_empty(hash))
1952 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1955 /* Disabling always succeeds */
1956 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1958 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1960 if (ftrace_hash_empty(hash))
1963 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1966 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1967 struct ftrace_hash *new_hash)
1969 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1971 if (ftrace_hash_empty(old_hash))
1974 if (ftrace_hash_empty(new_hash))
1977 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
1980 static void print_ip_ins(const char *fmt, const unsigned char *p)
1982 char ins[MCOUNT_INSN_SIZE];
1985 if (copy_from_kernel_nofault(ins, p, MCOUNT_INSN_SIZE)) {
1986 printk(KERN_CONT "%s[FAULT] %px\n", fmt, p);
1990 printk(KERN_CONT "%s", fmt);
1992 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1993 printk(KERN_CONT "%s%02x", i ? ":" : "", ins[i]);
1996 enum ftrace_bug_type ftrace_bug_type;
1997 const void *ftrace_expected;
1999 static void print_bug_type(void)
2001 switch (ftrace_bug_type) {
2002 case FTRACE_BUG_UNKNOWN:
2004 case FTRACE_BUG_INIT:
2005 pr_info("Initializing ftrace call sites\n");
2007 case FTRACE_BUG_NOP:
2008 pr_info("Setting ftrace call site to NOP\n");
2010 case FTRACE_BUG_CALL:
2011 pr_info("Setting ftrace call site to call ftrace function\n");
2013 case FTRACE_BUG_UPDATE:
2014 pr_info("Updating ftrace call site to call a different ftrace function\n");
2020 * ftrace_bug - report and shutdown function tracer
2021 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2022 * @rec: The record that failed
2024 * The arch code that enables or disables the function tracing
2025 * can call ftrace_bug() when it has detected a problem in
2026 * modifying the code. @failed should be one of either:
2027 * EFAULT - if the problem happens on reading the @ip address
2028 * EINVAL - if what is read at @ip is not what was expected
2029 * EPERM - if the problem happens on writing to the @ip address
2031 void ftrace_bug(int failed, struct dyn_ftrace *rec)
2033 unsigned long ip = rec ? rec->ip : 0;
2035 pr_info("------------[ ftrace bug ]------------\n");
2039 pr_info("ftrace faulted on modifying ");
2040 print_ip_sym(KERN_INFO, ip);
2043 pr_info("ftrace failed to modify ");
2044 print_ip_sym(KERN_INFO, ip);
2045 print_ip_ins(" actual: ", (unsigned char *)ip);
2047 if (ftrace_expected) {
2048 print_ip_ins(" expected: ", ftrace_expected);
2053 pr_info("ftrace faulted on writing ");
2054 print_ip_sym(KERN_INFO, ip);
2057 pr_info("ftrace faulted on unknown error ");
2058 print_ip_sym(KERN_INFO, ip);
2062 struct ftrace_ops *ops = NULL;
2064 pr_info("ftrace record flags: %lx\n", rec->flags);
2065 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2066 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2067 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2068 ops = ftrace_find_tramp_ops_any(rec);
2071 pr_cont("\ttramp: %pS (%pS)",
2072 (void *)ops->trampoline,
2074 ops = ftrace_find_tramp_ops_next(rec, ops);
2077 pr_cont("\ttramp: ERROR!");
2080 ip = ftrace_get_addr_curr(rec);
2081 pr_cont("\n expected tramp: %lx\n", ip);
2084 FTRACE_WARN_ON_ONCE(1);
2087 static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2089 unsigned long flag = 0UL;
2091 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2093 if (rec->flags & FTRACE_FL_DISABLED)
2094 return FTRACE_UPDATE_IGNORE;
2097 * If we are updating calls:
2099 * If the record has a ref count, then we need to enable it
2100 * because someone is using it.
2102 * Otherwise we make sure its disabled.
2104 * If we are disabling calls, then disable all records that
2107 if (enable && ftrace_rec_count(rec))
2108 flag = FTRACE_FL_ENABLED;
2111 * If enabling and the REGS flag does not match the REGS_EN, or
2112 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2113 * this record. Set flags to fail the compare against ENABLED.
2114 * Same for direct calls.
2117 if (!(rec->flags & FTRACE_FL_REGS) !=
2118 !(rec->flags & FTRACE_FL_REGS_EN))
2119 flag |= FTRACE_FL_REGS;
2121 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2122 !(rec->flags & FTRACE_FL_TRAMP_EN))
2123 flag |= FTRACE_FL_TRAMP;
2126 * Direct calls are special, as count matters.
2127 * We must test the record for direct, if the
2128 * DIRECT and DIRECT_EN do not match, but only
2129 * if the count is 1. That's because, if the
2130 * count is something other than one, we do not
2131 * want the direct enabled (it will be done via the
2132 * direct helper). But if DIRECT_EN is set, and
2133 * the count is not one, we need to clear it.
2135 if (ftrace_rec_count(rec) == 1) {
2136 if (!(rec->flags & FTRACE_FL_DIRECT) !=
2137 !(rec->flags & FTRACE_FL_DIRECT_EN))
2138 flag |= FTRACE_FL_DIRECT;
2139 } else if (rec->flags & FTRACE_FL_DIRECT_EN) {
2140 flag |= FTRACE_FL_DIRECT;
2144 /* If the state of this record hasn't changed, then do nothing */
2145 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2146 return FTRACE_UPDATE_IGNORE;
2149 /* Save off if rec is being enabled (for return value) */
2150 flag ^= rec->flags & FTRACE_FL_ENABLED;
2153 rec->flags |= FTRACE_FL_ENABLED;
2154 if (flag & FTRACE_FL_REGS) {
2155 if (rec->flags & FTRACE_FL_REGS)
2156 rec->flags |= FTRACE_FL_REGS_EN;
2158 rec->flags &= ~FTRACE_FL_REGS_EN;
2160 if (flag & FTRACE_FL_TRAMP) {
2161 if (rec->flags & FTRACE_FL_TRAMP)
2162 rec->flags |= FTRACE_FL_TRAMP_EN;
2164 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2167 if (flag & FTRACE_FL_DIRECT) {
2169 * If there's only one user (direct_ops helper)
2170 * then we can call the direct function
2171 * directly (no ftrace trampoline).
2173 if (ftrace_rec_count(rec) == 1) {
2174 if (rec->flags & FTRACE_FL_DIRECT)
2175 rec->flags |= FTRACE_FL_DIRECT_EN;
2177 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2180 * Can only call directly if there's
2181 * only one callback to the function.
2183 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2189 * If this record is being updated from a nop, then
2190 * return UPDATE_MAKE_CALL.
2192 * return UPDATE_MODIFY_CALL to tell the caller to convert
2193 * from the save regs, to a non-save regs function or
2194 * vice versa, or from a trampoline call.
2196 if (flag & FTRACE_FL_ENABLED) {
2197 ftrace_bug_type = FTRACE_BUG_CALL;
2198 return FTRACE_UPDATE_MAKE_CALL;
2201 ftrace_bug_type = FTRACE_BUG_UPDATE;
2202 return FTRACE_UPDATE_MODIFY_CALL;
2206 /* If there's no more users, clear all flags */
2207 if (!ftrace_rec_count(rec))
2211 * Just disable the record, but keep the ops TRAMP
2212 * and REGS states. The _EN flags must be disabled though.
2214 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2215 FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN);
2218 ftrace_bug_type = FTRACE_BUG_NOP;
2219 return FTRACE_UPDATE_MAKE_NOP;
2223 * ftrace_update_record - set a record that now is tracing or not
2224 * @rec: the record to update
2225 * @enable: set to true if the record is tracing, false to force disable
2227 * The records that represent all functions that can be traced need
2228 * to be updated when tracing has been enabled.
2230 int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2232 return ftrace_check_record(rec, enable, true);
2236 * ftrace_test_record - check if the record has been enabled or not
2237 * @rec: the record to test
2238 * @enable: set to true to check if enabled, false if it is disabled
2240 * The arch code may need to test if a record is already set to
2241 * tracing to determine how to modify the function code that it
2244 int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2246 return ftrace_check_record(rec, enable, false);
2249 static struct ftrace_ops *
2250 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2252 struct ftrace_ops *op;
2253 unsigned long ip = rec->ip;
2255 do_for_each_ftrace_op(op, ftrace_ops_list) {
2257 if (!op->trampoline)
2260 if (hash_contains_ip(ip, op->func_hash))
2262 } while_for_each_ftrace_op(op);
2267 static struct ftrace_ops *
2268 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude)
2270 struct ftrace_ops *op;
2271 unsigned long ip = rec->ip;
2273 do_for_each_ftrace_op(op, ftrace_ops_list) {
2275 if (op == op_exclude || !op->trampoline)
2278 if (hash_contains_ip(ip, op->func_hash))
2280 } while_for_each_ftrace_op(op);
2285 static struct ftrace_ops *
2286 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2287 struct ftrace_ops *op)
2289 unsigned long ip = rec->ip;
2291 while_for_each_ftrace_op(op) {
2293 if (!op->trampoline)
2296 if (hash_contains_ip(ip, op->func_hash))
2303 static struct ftrace_ops *
2304 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2306 struct ftrace_ops *op;
2307 unsigned long ip = rec->ip;
2310 * Need to check removed ops first.
2311 * If they are being removed, and this rec has a tramp,
2312 * and this rec is in the ops list, then it would be the
2313 * one with the tramp.
2316 if (hash_contains_ip(ip, &removed_ops->old_hash))
2321 * Need to find the current trampoline for a rec.
2322 * Now, a trampoline is only attached to a rec if there
2323 * was a single 'ops' attached to it. But this can be called
2324 * when we are adding another op to the rec or removing the
2325 * current one. Thus, if the op is being added, we can
2326 * ignore it because it hasn't attached itself to the rec
2329 * If an ops is being modified (hooking to different functions)
2330 * then we don't care about the new functions that are being
2331 * added, just the old ones (that are probably being removed).
2333 * If we are adding an ops to a function that already is using
2334 * a trampoline, it needs to be removed (trampolines are only
2335 * for single ops connected), then an ops that is not being
2336 * modified also needs to be checked.
2338 do_for_each_ftrace_op(op, ftrace_ops_list) {
2340 if (!op->trampoline)
2344 * If the ops is being added, it hasn't gotten to
2345 * the point to be removed from this tree yet.
2347 if (op->flags & FTRACE_OPS_FL_ADDING)
2352 * If the ops is being modified and is in the old
2353 * hash, then it is probably being removed from this
2356 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2357 hash_contains_ip(ip, &op->old_hash))
2360 * If the ops is not being added or modified, and it's
2361 * in its normal filter hash, then this must be the one
2364 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2365 hash_contains_ip(ip, op->func_hash))
2368 } while_for_each_ftrace_op(op);
2373 static struct ftrace_ops *
2374 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2376 struct ftrace_ops *op;
2377 unsigned long ip = rec->ip;
2379 do_for_each_ftrace_op(op, ftrace_ops_list) {
2380 /* pass rec in as regs to have non-NULL val */
2381 if (hash_contains_ip(ip, op->func_hash))
2383 } while_for_each_ftrace_op(op);
2388 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
2389 /* Protected by rcu_tasks for reading, and direct_mutex for writing */
2390 static struct ftrace_hash *direct_functions = EMPTY_HASH;
2391 static DEFINE_MUTEX(direct_mutex);
2392 int ftrace_direct_func_count;
2395 * Search the direct_functions hash to see if the given instruction pointer
2396 * has a direct caller attached to it.
2398 unsigned long ftrace_find_rec_direct(unsigned long ip)
2400 struct ftrace_func_entry *entry;
2402 entry = __ftrace_lookup_ip(direct_functions, ip);
2406 return entry->direct;
2409 static struct ftrace_func_entry*
2410 ftrace_add_rec_direct(unsigned long ip, unsigned long addr,
2411 struct ftrace_hash **free_hash)
2413 struct ftrace_func_entry *entry;
2415 if (ftrace_hash_empty(direct_functions) ||
2416 direct_functions->count > 2 * (1 << direct_functions->size_bits)) {
2417 struct ftrace_hash *new_hash;
2418 int size = ftrace_hash_empty(direct_functions) ? 0 :
2419 direct_functions->count + 1;
2424 new_hash = dup_hash(direct_functions, size);
2428 *free_hash = direct_functions;
2429 direct_functions = new_hash;
2432 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2437 entry->direct = addr;
2438 __add_hash_entry(direct_functions, entry);
2442 static void call_direct_funcs(unsigned long ip, unsigned long pip,
2443 struct ftrace_ops *ops, struct ftrace_regs *fregs)
2445 struct pt_regs *regs = ftrace_get_regs(fregs);
2448 addr = ftrace_find_rec_direct(ip);
2452 arch_ftrace_set_direct_caller(regs, addr);
2455 struct ftrace_ops direct_ops = {
2456 .func = call_direct_funcs,
2457 .flags = FTRACE_OPS_FL_IPMODIFY
2458 | FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
2459 | FTRACE_OPS_FL_PERMANENT,
2461 * By declaring the main trampoline as this trampoline
2462 * it will never have one allocated for it. Allocated
2463 * trampolines should not call direct functions.
2464 * The direct_ops should only be called by the builtin
2465 * ftrace_regs_caller trampoline.
2467 .trampoline = FTRACE_REGS_ADDR,
2469 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
2472 * ftrace_get_addr_new - Get the call address to set to
2473 * @rec: The ftrace record descriptor
2475 * If the record has the FTRACE_FL_REGS set, that means that it
2476 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2477 * is not set, then it wants to convert to the normal callback.
2479 * Returns the address of the trampoline to set to
2481 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2483 struct ftrace_ops *ops;
2486 if ((rec->flags & FTRACE_FL_DIRECT) &&
2487 (ftrace_rec_count(rec) == 1)) {
2488 addr = ftrace_find_rec_direct(rec->ip);
2494 /* Trampolines take precedence over regs */
2495 if (rec->flags & FTRACE_FL_TRAMP) {
2496 ops = ftrace_find_tramp_ops_new(rec);
2497 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2498 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2499 (void *)rec->ip, (void *)rec->ip, rec->flags);
2500 /* Ftrace is shutting down, return anything */
2501 return (unsigned long)FTRACE_ADDR;
2503 return ops->trampoline;
2506 if (rec->flags & FTRACE_FL_REGS)
2507 return (unsigned long)FTRACE_REGS_ADDR;
2509 return (unsigned long)FTRACE_ADDR;
2513 * ftrace_get_addr_curr - Get the call address that is already there
2514 * @rec: The ftrace record descriptor
2516 * The FTRACE_FL_REGS_EN is set when the record already points to
2517 * a function that saves all the regs. Basically the '_EN' version
2518 * represents the current state of the function.
2520 * Returns the address of the trampoline that is currently being called
2522 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2524 struct ftrace_ops *ops;
2527 /* Direct calls take precedence over trampolines */
2528 if (rec->flags & FTRACE_FL_DIRECT_EN) {
2529 addr = ftrace_find_rec_direct(rec->ip);
2535 /* Trampolines take precedence over regs */
2536 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2537 ops = ftrace_find_tramp_ops_curr(rec);
2538 if (FTRACE_WARN_ON(!ops)) {
2539 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2540 (void *)rec->ip, (void *)rec->ip);
2541 /* Ftrace is shutting down, return anything */
2542 return (unsigned long)FTRACE_ADDR;
2544 return ops->trampoline;
2547 if (rec->flags & FTRACE_FL_REGS_EN)
2548 return (unsigned long)FTRACE_REGS_ADDR;
2550 return (unsigned long)FTRACE_ADDR;
2554 __ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2556 unsigned long ftrace_old_addr;
2557 unsigned long ftrace_addr;
2560 ftrace_addr = ftrace_get_addr_new(rec);
2562 /* This needs to be done before we call ftrace_update_record */
2563 ftrace_old_addr = ftrace_get_addr_curr(rec);
2565 ret = ftrace_update_record(rec, enable);
2567 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2570 case FTRACE_UPDATE_IGNORE:
2573 case FTRACE_UPDATE_MAKE_CALL:
2574 ftrace_bug_type = FTRACE_BUG_CALL;
2575 return ftrace_make_call(rec, ftrace_addr);
2577 case FTRACE_UPDATE_MAKE_NOP:
2578 ftrace_bug_type = FTRACE_BUG_NOP;
2579 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2581 case FTRACE_UPDATE_MODIFY_CALL:
2582 ftrace_bug_type = FTRACE_BUG_UPDATE;
2583 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2586 return -1; /* unknown ftrace bug */
2589 void __weak ftrace_replace_code(int mod_flags)
2591 struct dyn_ftrace *rec;
2592 struct ftrace_page *pg;
2593 bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2594 int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2597 if (unlikely(ftrace_disabled))
2600 do_for_each_ftrace_rec(pg, rec) {
2602 if (rec->flags & FTRACE_FL_DISABLED)
2605 failed = __ftrace_replace_code(rec, enable);
2607 ftrace_bug(failed, rec);
2608 /* Stop processing */
2613 } while_for_each_ftrace_rec();
2616 struct ftrace_rec_iter {
2617 struct ftrace_page *pg;
2622 * ftrace_rec_iter_start - start up iterating over traced functions
2624 * Returns an iterator handle that is used to iterate over all
2625 * the records that represent address locations where functions
2628 * May return NULL if no records are available.
2630 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2633 * We only use a single iterator.
2634 * Protected by the ftrace_lock mutex.
2636 static struct ftrace_rec_iter ftrace_rec_iter;
2637 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2639 iter->pg = ftrace_pages_start;
2642 /* Could have empty pages */
2643 while (iter->pg && !iter->pg->index)
2644 iter->pg = iter->pg->next;
2653 * ftrace_rec_iter_next - get the next record to process.
2654 * @iter: The handle to the iterator.
2656 * Returns the next iterator after the given iterator @iter.
2658 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2662 if (iter->index >= iter->pg->index) {
2663 iter->pg = iter->pg->next;
2666 /* Could have empty pages */
2667 while (iter->pg && !iter->pg->index)
2668 iter->pg = iter->pg->next;
2678 * ftrace_rec_iter_record - get the record at the iterator location
2679 * @iter: The current iterator location
2681 * Returns the record that the current @iter is at.
2683 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2685 return &iter->pg->records[iter->index];
2689 ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
2693 if (unlikely(ftrace_disabled))
2696 ret = ftrace_init_nop(mod, rec);
2698 ftrace_bug_type = FTRACE_BUG_INIT;
2699 ftrace_bug(ret, rec);
2706 * archs can override this function if they must do something
2707 * before the modifying code is performed.
2709 void __weak ftrace_arch_code_modify_prepare(void)
2714 * archs can override this function if they must do something
2715 * after the modifying code is performed.
2717 void __weak ftrace_arch_code_modify_post_process(void)
2721 void ftrace_modify_all_code(int command)
2723 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2727 if (command & FTRACE_MAY_SLEEP)
2728 mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2731 * If the ftrace_caller calls a ftrace_ops func directly,
2732 * we need to make sure that it only traces functions it
2733 * expects to trace. When doing the switch of functions,
2734 * we need to update to the ftrace_ops_list_func first
2735 * before the transition between old and new calls are set,
2736 * as the ftrace_ops_list_func will check the ops hashes
2737 * to make sure the ops are having the right functions
2741 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2742 if (FTRACE_WARN_ON(err))
2746 if (command & FTRACE_UPDATE_CALLS)
2747 ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2748 else if (command & FTRACE_DISABLE_CALLS)
2749 ftrace_replace_code(mod_flags);
2751 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2752 function_trace_op = set_function_trace_op;
2754 /* If irqs are disabled, we are in stop machine */
2755 if (!irqs_disabled())
2756 smp_call_function(ftrace_sync_ipi, NULL, 1);
2757 err = ftrace_update_ftrace_func(ftrace_trace_function);
2758 if (FTRACE_WARN_ON(err))
2762 if (command & FTRACE_START_FUNC_RET)
2763 err = ftrace_enable_ftrace_graph_caller();
2764 else if (command & FTRACE_STOP_FUNC_RET)
2765 err = ftrace_disable_ftrace_graph_caller();
2766 FTRACE_WARN_ON(err);
2769 static int __ftrace_modify_code(void *data)
2771 int *command = data;
2773 ftrace_modify_all_code(*command);
2779 * ftrace_run_stop_machine - go back to the stop machine method
2780 * @command: The command to tell ftrace what to do
2782 * If an arch needs to fall back to the stop machine method, the
2783 * it can call this function.
2785 void ftrace_run_stop_machine(int command)
2787 stop_machine(__ftrace_modify_code, &command, NULL);
2791 * arch_ftrace_update_code - modify the code to trace or not trace
2792 * @command: The command that needs to be done
2794 * Archs can override this function if it does not need to
2795 * run stop_machine() to modify code.
2797 void __weak arch_ftrace_update_code(int command)
2799 ftrace_run_stop_machine(command);
2802 static void ftrace_run_update_code(int command)
2804 ftrace_arch_code_modify_prepare();
2807 * By default we use stop_machine() to modify the code.
2808 * But archs can do what ever they want as long as it
2809 * is safe. The stop_machine() is the safest, but also
2810 * produces the most overhead.
2812 arch_ftrace_update_code(command);
2814 ftrace_arch_code_modify_post_process();
2817 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2818 struct ftrace_ops_hash *old_hash)
2820 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2821 ops->old_hash.filter_hash = old_hash->filter_hash;
2822 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2823 ftrace_run_update_code(command);
2824 ops->old_hash.filter_hash = NULL;
2825 ops->old_hash.notrace_hash = NULL;
2826 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2829 static ftrace_func_t saved_ftrace_func;
2830 static int ftrace_start_up;
2832 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2836 /* List of trace_ops that have allocated trampolines */
2837 static LIST_HEAD(ftrace_ops_trampoline_list);
2839 static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops *ops)
2841 lockdep_assert_held(&ftrace_lock);
2842 list_add_rcu(&ops->list, &ftrace_ops_trampoline_list);
2845 static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops)
2847 lockdep_assert_held(&ftrace_lock);
2848 list_del_rcu(&ops->list);
2853 * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols
2854 * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is
2857 #define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace"
2858 #define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"
2860 static void ftrace_trampoline_free(struct ftrace_ops *ops)
2862 if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
2865 * Record the text poke event before the ksymbol unregister
2868 perf_event_text_poke((void *)ops->trampoline,
2869 (void *)ops->trampoline,
2870 ops->trampoline_size, NULL, 0);
2871 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
2872 ops->trampoline, ops->trampoline_size,
2873 true, FTRACE_TRAMPOLINE_SYM);
2874 /* Remove from kallsyms after the perf events */
2875 ftrace_remove_trampoline_from_kallsyms(ops);
2878 arch_ftrace_trampoline_free(ops);
2881 static void ftrace_startup_enable(int command)
2883 if (saved_ftrace_func != ftrace_trace_function) {
2884 saved_ftrace_func = ftrace_trace_function;
2885 command |= FTRACE_UPDATE_TRACE_FUNC;
2888 if (!command || !ftrace_enabled)
2891 ftrace_run_update_code(command);
2894 static void ftrace_startup_all(int command)
2896 update_all_ops = true;
2897 ftrace_startup_enable(command);
2898 update_all_ops = false;
2901 int ftrace_startup(struct ftrace_ops *ops, int command)
2905 if (unlikely(ftrace_disabled))
2908 ret = __register_ftrace_function(ops);
2915 * Note that ftrace probes uses this to start up
2916 * and modify functions it will probe. But we still
2917 * set the ADDING flag for modification, as probes
2918 * do not have trampolines. If they add them in the
2919 * future, then the probes will need to distinguish
2920 * between adding and updating probes.
2922 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2924 ret = ftrace_hash_ipmodify_enable(ops);
2926 /* Rollback registration process */
2927 __unregister_ftrace_function(ops);
2929 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2930 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2931 ftrace_trampoline_free(ops);
2935 if (ftrace_hash_rec_enable(ops, 1))
2936 command |= FTRACE_UPDATE_CALLS;
2938 ftrace_startup_enable(command);
2940 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2945 int ftrace_shutdown(struct ftrace_ops *ops, int command)
2949 if (unlikely(ftrace_disabled))
2952 ret = __unregister_ftrace_function(ops);
2958 * Just warn in case of unbalance, no need to kill ftrace, it's not
2959 * critical but the ftrace_call callers may be never nopped again after
2960 * further ftrace uses.
2962 WARN_ON_ONCE(ftrace_start_up < 0);
2964 /* Disabling ipmodify never fails */
2965 ftrace_hash_ipmodify_disable(ops);
2967 if (ftrace_hash_rec_disable(ops, 1))
2968 command |= FTRACE_UPDATE_CALLS;
2970 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2972 if (saved_ftrace_func != ftrace_trace_function) {
2973 saved_ftrace_func = ftrace_trace_function;
2974 command |= FTRACE_UPDATE_TRACE_FUNC;
2977 if (!command || !ftrace_enabled) {
2979 * If these are dynamic or per_cpu ops, they still
2980 * need their data freed. Since, function tracing is
2981 * not currently active, we can just free them
2982 * without synchronizing all CPUs.
2984 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2991 * If the ops uses a trampoline, then it needs to be
2992 * tested first on update.
2994 ops->flags |= FTRACE_OPS_FL_REMOVING;
2997 /* The trampoline logic checks the old hashes */
2998 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2999 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
3001 ftrace_run_update_code(command);
3004 * If there's no more ops registered with ftrace, run a
3005 * sanity check to make sure all rec flags are cleared.
3007 if (rcu_dereference_protected(ftrace_ops_list,
3008 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
3009 struct ftrace_page *pg;
3010 struct dyn_ftrace *rec;
3012 do_for_each_ftrace_rec(pg, rec) {
3013 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
3014 pr_warn(" %pS flags:%lx\n",
3015 (void *)rec->ip, rec->flags);
3016 } while_for_each_ftrace_rec();
3019 ops->old_hash.filter_hash = NULL;
3020 ops->old_hash.notrace_hash = NULL;
3023 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
3026 * Dynamic ops may be freed, we must make sure that all
3027 * callers are done before leaving this function.
3028 * The same goes for freeing the per_cpu data of the per_cpu
3031 if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
3033 * We need to do a hard force of sched synchronization.
3034 * This is because we use preempt_disable() to do RCU, but
3035 * the function tracers can be called where RCU is not watching
3036 * (like before user_exit()). We can not rely on the RCU
3037 * infrastructure to do the synchronization, thus we must do it
3040 synchronize_rcu_tasks_rude();
3043 * When the kernel is preemptive, tasks can be preempted
3044 * while on a ftrace trampoline. Just scheduling a task on
3045 * a CPU is not good enough to flush them. Calling
3046 * synchronize_rcu_tasks() will wait for those tasks to
3047 * execute and either schedule voluntarily or enter user space.
3049 if (IS_ENABLED(CONFIG_PREEMPTION))
3050 synchronize_rcu_tasks();
3053 ftrace_trampoline_free(ops);
3059 static u64 ftrace_update_time;
3060 unsigned long ftrace_update_tot_cnt;
3061 unsigned long ftrace_number_of_pages;
3062 unsigned long ftrace_number_of_groups;
3064 static inline int ops_traces_mod(struct ftrace_ops *ops)
3067 * Filter_hash being empty will default to trace module.
3068 * But notrace hash requires a test of individual module functions.
3070 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
3071 ftrace_hash_empty(ops->func_hash->notrace_hash);
3075 * Check if the current ops references the record.
3077 * If the ops traces all functions, then it was already accounted for.
3078 * If the ops does not trace the current record function, skip it.
3079 * If the ops ignores the function via notrace filter, skip it.
3082 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3084 /* If ops isn't enabled, ignore it */
3085 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
3088 /* If ops traces all then it includes this function */
3089 if (ops_traces_mod(ops))
3092 /* The function must be in the filter */
3093 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
3094 !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
3097 /* If in notrace hash, we ignore it too */
3098 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
3104 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
3106 bool init_nop = ftrace_need_init_nop();
3107 struct ftrace_page *pg;
3108 struct dyn_ftrace *p;
3110 unsigned long update_cnt = 0;
3111 unsigned long rec_flags = 0;
3114 start = ftrace_now(raw_smp_processor_id());
3117 * When a module is loaded, this function is called to convert
3118 * the calls to mcount in its text to nops, and also to create
3119 * an entry in the ftrace data. Now, if ftrace is activated
3120 * after this call, but before the module sets its text to
3121 * read-only, the modification of enabling ftrace can fail if
3122 * the read-only is done while ftrace is converting the calls.
3123 * To prevent this, the module's records are set as disabled
3124 * and will be enabled after the call to set the module's text
3128 rec_flags |= FTRACE_FL_DISABLED;
3130 for (pg = new_pgs; pg; pg = pg->next) {
3132 for (i = 0; i < pg->index; i++) {
3134 /* If something went wrong, bail without enabling anything */
3135 if (unlikely(ftrace_disabled))
3138 p = &pg->records[i];
3139 p->flags = rec_flags;
3142 * Do the initial record conversion from mcount jump
3143 * to the NOP instructions.
3145 if (init_nop && !ftrace_nop_initialize(mod, p))
3152 stop = ftrace_now(raw_smp_processor_id());
3153 ftrace_update_time = stop - start;
3154 ftrace_update_tot_cnt += update_cnt;
3159 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3165 if (WARN_ON(!count))
3168 /* We want to fill as much as possible, with no empty pages */
3169 pages = DIV_ROUND_UP(count, ENTRIES_PER_PAGE);
3170 order = fls(pages) - 1;
3173 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3176 /* if we can't allocate this size, try something smaller */
3183 ftrace_number_of_pages += 1 << order;
3184 ftrace_number_of_groups++;
3186 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3195 static struct ftrace_page *
3196 ftrace_allocate_pages(unsigned long num_to_init)
3198 struct ftrace_page *start_pg;
3199 struct ftrace_page *pg;
3205 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3210 * Try to allocate as much as possible in one continues
3211 * location that fills in all of the space. We want to
3212 * waste as little space as possible.
3215 cnt = ftrace_allocate_records(pg, num_to_init);
3223 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3236 free_pages((unsigned long)pg->records, pg->order);
3237 ftrace_number_of_pages -= 1 << pg->order;
3239 start_pg = pg->next;
3242 ftrace_number_of_groups--;
3244 pr_info("ftrace: FAILED to allocate memory for functions\n");
3248 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3250 struct ftrace_iterator {
3254 struct ftrace_page *pg;
3255 struct dyn_ftrace *func;
3256 struct ftrace_func_probe *probe;
3257 struct ftrace_func_entry *probe_entry;
3258 struct trace_parser parser;
3259 struct ftrace_hash *hash;
3260 struct ftrace_ops *ops;
3261 struct trace_array *tr;
3262 struct list_head *mod_list;
3269 t_probe_next(struct seq_file *m, loff_t *pos)
3271 struct ftrace_iterator *iter = m->private;
3272 struct trace_array *tr = iter->ops->private;
3273 struct list_head *func_probes;
3274 struct ftrace_hash *hash;
3275 struct list_head *next;
3276 struct hlist_node *hnd = NULL;
3277 struct hlist_head *hhd;
3286 func_probes = &tr->func_probes;
3287 if (list_empty(func_probes))
3291 next = func_probes->next;
3292 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3295 if (iter->probe_entry)
3296 hnd = &iter->probe_entry->hlist;
3298 hash = iter->probe->ops.func_hash->filter_hash;
3301 * A probe being registered may temporarily have an empty hash
3302 * and it's at the end of the func_probes list.
3304 if (!hash || hash == EMPTY_HASH)
3307 size = 1 << hash->size_bits;
3310 if (iter->pidx >= size) {
3311 if (iter->probe->list.next == func_probes)
3313 next = iter->probe->list.next;
3314 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3315 hash = iter->probe->ops.func_hash->filter_hash;
3316 size = 1 << hash->size_bits;
3320 hhd = &hash->buckets[iter->pidx];
3322 if (hlist_empty(hhd)) {
3338 if (WARN_ON_ONCE(!hnd))
3341 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3346 static void *t_probe_start(struct seq_file *m, loff_t *pos)
3348 struct ftrace_iterator *iter = m->private;
3352 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3355 if (iter->mod_pos > *pos)
3359 iter->probe_entry = NULL;
3361 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3362 p = t_probe_next(m, &l);
3369 /* Only set this if we have an item */
3370 iter->flags |= FTRACE_ITER_PROBE;
3376 t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3378 struct ftrace_func_entry *probe_entry;
3379 struct ftrace_probe_ops *probe_ops;
3380 struct ftrace_func_probe *probe;
3382 probe = iter->probe;
3383 probe_entry = iter->probe_entry;
3385 if (WARN_ON_ONCE(!probe || !probe_entry))
3388 probe_ops = probe->probe_ops;
3390 if (probe_ops->print)
3391 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3393 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3394 (void *)probe_ops->func);
3400 t_mod_next(struct seq_file *m, loff_t *pos)
3402 struct ftrace_iterator *iter = m->private;
3403 struct trace_array *tr = iter->tr;
3408 iter->mod_list = iter->mod_list->next;
3410 if (iter->mod_list == &tr->mod_trace ||
3411 iter->mod_list == &tr->mod_notrace) {
3412 iter->flags &= ~FTRACE_ITER_MOD;
3416 iter->mod_pos = *pos;
3421 static void *t_mod_start(struct seq_file *m, loff_t *pos)
3423 struct ftrace_iterator *iter = m->private;
3427 if (iter->func_pos > *pos)
3430 iter->mod_pos = iter->func_pos;
3432 /* probes are only available if tr is set */
3436 for (l = 0; l <= (*pos - iter->func_pos); ) {
3437 p = t_mod_next(m, &l);
3442 iter->flags &= ~FTRACE_ITER_MOD;
3443 return t_probe_start(m, pos);
3446 /* Only set this if we have an item */
3447 iter->flags |= FTRACE_ITER_MOD;
3453 t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3455 struct ftrace_mod_load *ftrace_mod;
3456 struct trace_array *tr = iter->tr;
3458 if (WARN_ON_ONCE(!iter->mod_list) ||
3459 iter->mod_list == &tr->mod_trace ||
3460 iter->mod_list == &tr->mod_notrace)
3463 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3465 if (ftrace_mod->func)
3466 seq_printf(m, "%s", ftrace_mod->func);
3470 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3476 t_func_next(struct seq_file *m, loff_t *pos)
3478 struct ftrace_iterator *iter = m->private;
3479 struct dyn_ftrace *rec = NULL;
3484 if (iter->idx >= iter->pg->index) {
3485 if (iter->pg->next) {
3486 iter->pg = iter->pg->next;
3491 rec = &iter->pg->records[iter->idx++];
3492 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3493 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3495 ((iter->flags & FTRACE_ITER_ENABLED) &&
3496 !(rec->flags & FTRACE_FL_ENABLED))) {
3506 iter->pos = iter->func_pos = *pos;
3513 t_next(struct seq_file *m, void *v, loff_t *pos)
3515 struct ftrace_iterator *iter = m->private;
3516 loff_t l = *pos; /* t_probe_start() must use original pos */
3519 if (unlikely(ftrace_disabled))
3522 if (iter->flags & FTRACE_ITER_PROBE)
3523 return t_probe_next(m, pos);
3525 if (iter->flags & FTRACE_ITER_MOD)
3526 return t_mod_next(m, pos);
3528 if (iter->flags & FTRACE_ITER_PRINTALL) {
3529 /* next must increment pos, and t_probe_start does not */
3531 return t_mod_start(m, &l);
3534 ret = t_func_next(m, pos);
3537 return t_mod_start(m, &l);
3542 static void reset_iter_read(struct ftrace_iterator *iter)
3546 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3549 static void *t_start(struct seq_file *m, loff_t *pos)
3551 struct ftrace_iterator *iter = m->private;
3555 mutex_lock(&ftrace_lock);
3557 if (unlikely(ftrace_disabled))
3561 * If an lseek was done, then reset and start from beginning.
3563 if (*pos < iter->pos)
3564 reset_iter_read(iter);
3567 * For set_ftrace_filter reading, if we have the filter
3568 * off, we can short cut and just print out that all
3569 * functions are enabled.
3571 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3572 ftrace_hash_empty(iter->hash)) {
3573 iter->func_pos = 1; /* Account for the message */
3575 return t_mod_start(m, pos);
3576 iter->flags |= FTRACE_ITER_PRINTALL;
3577 /* reset in case of seek/pread */
3578 iter->flags &= ~FTRACE_ITER_PROBE;
3582 if (iter->flags & FTRACE_ITER_MOD)
3583 return t_mod_start(m, pos);
3586 * Unfortunately, we need to restart at ftrace_pages_start
3587 * every time we let go of the ftrace_mutex. This is because
3588 * those pointers can change without the lock.
3590 iter->pg = ftrace_pages_start;
3592 for (l = 0; l <= *pos; ) {
3593 p = t_func_next(m, &l);
3599 return t_mod_start(m, pos);
3604 static void t_stop(struct seq_file *m, void *p)
3606 mutex_unlock(&ftrace_lock);
3610 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3615 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3616 struct dyn_ftrace *rec)
3620 ptr = arch_ftrace_trampoline_func(ops, rec);
3622 seq_printf(m, " ->%pS", ptr);
3625 #ifdef FTRACE_MCOUNT_MAX_OFFSET
3627 * Weak functions can still have an mcount/fentry that is saved in
3628 * the __mcount_loc section. These can be detected by having a
3629 * symbol offset of greater than FTRACE_MCOUNT_MAX_OFFSET, as the
3630 * symbol found by kallsyms is not the function that the mcount/fentry
3631 * is part of. The offset is much greater in these cases.
3633 * Test the record to make sure that the ip points to a valid kallsyms
3634 * and if not, mark it disabled.
3636 static int test_for_valid_rec(struct dyn_ftrace *rec)
3638 char str[KSYM_SYMBOL_LEN];
3639 unsigned long offset;
3642 ret = kallsyms_lookup(rec->ip, NULL, &offset, NULL, str);
3644 /* Weak functions can cause invalid addresses */
3645 if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
3646 rec->flags |= FTRACE_FL_DISABLED;
3652 static struct workqueue_struct *ftrace_check_wq __initdata;
3653 static struct work_struct ftrace_check_work __initdata;
3656 * Scan all the mcount/fentry entries to make sure they are valid.
3658 static __init void ftrace_check_work_func(struct work_struct *work)
3660 struct ftrace_page *pg;
3661 struct dyn_ftrace *rec;
3663 mutex_lock(&ftrace_lock);
3664 do_for_each_ftrace_rec(pg, rec) {
3665 test_for_valid_rec(rec);
3666 } while_for_each_ftrace_rec();
3667 mutex_unlock(&ftrace_lock);
3670 static int __init ftrace_check_for_weak_functions(void)
3672 INIT_WORK(&ftrace_check_work, ftrace_check_work_func);
3674 ftrace_check_wq = alloc_workqueue("ftrace_check_wq", WQ_UNBOUND, 0);
3676 queue_work(ftrace_check_wq, &ftrace_check_work);
3680 static int __init ftrace_check_sync(void)
3682 /* Make sure the ftrace_check updates are finished */
3683 if (ftrace_check_wq)
3684 destroy_workqueue(ftrace_check_wq);
3688 late_initcall_sync(ftrace_check_sync);
3689 subsys_initcall(ftrace_check_for_weak_functions);
3691 static int print_rec(struct seq_file *m, unsigned long ip)
3693 unsigned long offset;
3694 char str[KSYM_SYMBOL_LEN];
3698 ret = kallsyms_lookup(ip, NULL, &offset, &modname, str);
3699 /* Weak functions can cause invalid addresses */
3700 if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
3701 snprintf(str, KSYM_SYMBOL_LEN, "%s_%ld",
3702 FTRACE_INVALID_FUNCTION, offset);
3708 seq_printf(m, " [%s]", modname);
3709 return ret == NULL ? -1 : 0;
3712 static inline int test_for_valid_rec(struct dyn_ftrace *rec)
3717 static inline int print_rec(struct seq_file *m, unsigned long ip)
3719 seq_printf(m, "%ps", (void *)ip);
3724 static int t_show(struct seq_file *m, void *v)
3726 struct ftrace_iterator *iter = m->private;
3727 struct dyn_ftrace *rec;
3729 if (iter->flags & FTRACE_ITER_PROBE)
3730 return t_probe_show(m, iter);
3732 if (iter->flags & FTRACE_ITER_MOD)
3733 return t_mod_show(m, iter);
3735 if (iter->flags & FTRACE_ITER_PRINTALL) {
3736 if (iter->flags & FTRACE_ITER_NOTRACE)
3737 seq_puts(m, "#### no functions disabled ####\n");
3739 seq_puts(m, "#### all functions enabled ####\n");
3748 if (print_rec(m, rec->ip)) {
3749 /* This should only happen when a rec is disabled */
3750 WARN_ON_ONCE(!(rec->flags & FTRACE_FL_DISABLED));
3755 if (iter->flags & FTRACE_ITER_ENABLED) {
3756 struct ftrace_ops *ops;
3758 seq_printf(m, " (%ld)%s%s%s",
3759 ftrace_rec_count(rec),
3760 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3761 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ",
3762 rec->flags & FTRACE_FL_DIRECT ? " D" : " ");
3763 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3764 ops = ftrace_find_tramp_ops_any(rec);
3767 seq_printf(m, "\ttramp: %pS (%pS)",
3768 (void *)ops->trampoline,
3770 add_trampoline_func(m, ops, rec);
3771 ops = ftrace_find_tramp_ops_next(rec, ops);
3774 seq_puts(m, "\ttramp: ERROR!");
3776 add_trampoline_func(m, NULL, rec);
3778 if (rec->flags & FTRACE_FL_DIRECT) {
3779 unsigned long direct;
3781 direct = ftrace_find_rec_direct(rec->ip);
3783 seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
3792 static const struct seq_operations show_ftrace_seq_ops = {
3800 ftrace_avail_open(struct inode *inode, struct file *file)
3802 struct ftrace_iterator *iter;
3805 ret = security_locked_down(LOCKDOWN_TRACEFS);
3809 if (unlikely(ftrace_disabled))
3812 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3816 iter->pg = ftrace_pages_start;
3817 iter->ops = &global_ops;
3823 ftrace_enabled_open(struct inode *inode, struct file *file)
3825 struct ftrace_iterator *iter;
3828 * This shows us what functions are currently being
3829 * traced and by what. Not sure if we want lockdown
3830 * to hide such critical information for an admin.
3831 * Although, perhaps it can show information we don't
3832 * want people to see, but if something is tracing
3833 * something, we probably want to know about it.
3836 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3840 iter->pg = ftrace_pages_start;
3841 iter->flags = FTRACE_ITER_ENABLED;
3842 iter->ops = &global_ops;
3848 * ftrace_regex_open - initialize function tracer filter files
3849 * @ops: The ftrace_ops that hold the hash filters
3850 * @flag: The type of filter to process
3851 * @inode: The inode, usually passed in to your open routine
3852 * @file: The file, usually passed in to your open routine
3854 * ftrace_regex_open() initializes the filter files for the
3855 * @ops. Depending on @flag it may process the filter hash or
3856 * the notrace hash of @ops. With this called from the open
3857 * routine, you can use ftrace_filter_write() for the write
3858 * routine if @flag has FTRACE_ITER_FILTER set, or
3859 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3860 * tracing_lseek() should be used as the lseek routine, and
3861 * release must call ftrace_regex_release().
3864 ftrace_regex_open(struct ftrace_ops *ops, int flag,
3865 struct inode *inode, struct file *file)
3867 struct ftrace_iterator *iter;
3868 struct ftrace_hash *hash;
3869 struct list_head *mod_head;
3870 struct trace_array *tr = ops->private;
3873 ftrace_ops_init(ops);
3875 if (unlikely(ftrace_disabled))
3878 if (tracing_check_open_get_tr(tr))
3881 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3885 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
3892 mutex_lock(&ops->func_hash->regex_lock);
3894 if (flag & FTRACE_ITER_NOTRACE) {
3895 hash = ops->func_hash->notrace_hash;
3896 mod_head = tr ? &tr->mod_notrace : NULL;
3898 hash = ops->func_hash->filter_hash;
3899 mod_head = tr ? &tr->mod_trace : NULL;
3902 iter->mod_list = mod_head;
3904 if (file->f_mode & FMODE_WRITE) {
3905 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3907 if (file->f_flags & O_TRUNC) {
3908 iter->hash = alloc_ftrace_hash(size_bits);
3909 clear_ftrace_mod_list(mod_head);
3911 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3915 trace_parser_put(&iter->parser);
3923 if (file->f_mode & FMODE_READ) {
3924 iter->pg = ftrace_pages_start;
3926 ret = seq_open(file, &show_ftrace_seq_ops);
3928 struct seq_file *m = file->private_data;
3932 free_ftrace_hash(iter->hash);
3933 trace_parser_put(&iter->parser);
3936 file->private_data = iter;
3939 mutex_unlock(&ops->func_hash->regex_lock);
3945 trace_array_put(tr);
3952 ftrace_filter_open(struct inode *inode, struct file *file)
3954 struct ftrace_ops *ops = inode->i_private;
3956 /* Checks for tracefs lockdown */
3957 return ftrace_regex_open(ops,
3958 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3963 ftrace_notrace_open(struct inode *inode, struct file *file)
3965 struct ftrace_ops *ops = inode->i_private;
3967 /* Checks for tracefs lockdown */
3968 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3972 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3973 struct ftrace_glob {
3980 * If symbols in an architecture don't correspond exactly to the user-visible
3981 * name of what they represent, it is possible to define this function to
3982 * perform the necessary adjustments.
3984 char * __weak arch_ftrace_match_adjust(char *str, const char *search)
3989 static int ftrace_match(char *str, struct ftrace_glob *g)
3994 str = arch_ftrace_match_adjust(str, g->search);
3998 if (strcmp(str, g->search) == 0)
4001 case MATCH_FRONT_ONLY:
4002 if (strncmp(str, g->search, g->len) == 0)
4005 case MATCH_MIDDLE_ONLY:
4006 if (strstr(str, g->search))
4009 case MATCH_END_ONLY:
4011 if (slen >= g->len &&
4012 memcmp(str + slen - g->len, g->search, g->len) == 0)
4016 if (glob_match(g->search, str))
4025 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
4027 struct ftrace_func_entry *entry;
4030 entry = ftrace_lookup_ip(hash, rec->ip);
4032 /* Do nothing if it doesn't exist */
4036 free_hash_entry(hash, entry);
4038 /* Do nothing if it exists */
4042 ret = add_hash_entry(hash, rec->ip);
4048 add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
4051 long index = simple_strtoul(func_g->search, NULL, 0);
4052 struct ftrace_page *pg;
4053 struct dyn_ftrace *rec;
4055 /* The index starts at 1 */
4059 do_for_each_ftrace_rec(pg, rec) {
4060 if (pg->index <= index) {
4062 /* this is a double loop, break goes to the next page */
4065 rec = &pg->records[index];
4066 enter_record(hash, rec, clear_filter);
4068 } while_for_each_ftrace_rec();
4072 #ifdef FTRACE_MCOUNT_MAX_OFFSET
4073 static int lookup_ip(unsigned long ip, char **modname, char *str)
4075 unsigned long offset;
4077 kallsyms_lookup(ip, NULL, &offset, modname, str);
4078 if (offset > FTRACE_MCOUNT_MAX_OFFSET)
4083 static int lookup_ip(unsigned long ip, char **modname, char *str)
4085 kallsyms_lookup(ip, NULL, NULL, modname, str);
4091 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
4092 struct ftrace_glob *mod_g, int exclude_mod)
4094 char str[KSYM_SYMBOL_LEN];
4097 if (lookup_ip(rec->ip, &modname, str)) {
4098 /* This should only happen when a rec is disabled */
4099 WARN_ON_ONCE(system_state == SYSTEM_RUNNING &&
4100 !(rec->flags & FTRACE_FL_DISABLED));
4105 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
4107 /* blank module name to match all modules */
4109 /* blank module globbing: modname xor exclude_mod */
4110 if (!exclude_mod != !modname)
4116 * exclude_mod is set to trace everything but the given
4117 * module. If it is set and the module matches, then
4118 * return 0. If it is not set, and the module doesn't match
4119 * also return 0. Otherwise, check the function to see if
4122 if (!mod_matches == !exclude_mod)
4125 /* blank search means to match all funcs in the mod */
4130 return ftrace_match(str, func_g);
4134 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
4136 struct ftrace_page *pg;
4137 struct dyn_ftrace *rec;
4138 struct ftrace_glob func_g = { .type = MATCH_FULL };
4139 struct ftrace_glob mod_g = { .type = MATCH_FULL };
4140 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
4141 int exclude_mod = 0;
4144 int clear_filter = 0;
4147 func_g.type = filter_parse_regex(func, len, &func_g.search,
4149 func_g.len = strlen(func_g.search);
4153 mod_g.type = filter_parse_regex(mod, strlen(mod),
4154 &mod_g.search, &exclude_mod);
4155 mod_g.len = strlen(mod_g.search);
4158 mutex_lock(&ftrace_lock);
4160 if (unlikely(ftrace_disabled))
4163 if (func_g.type == MATCH_INDEX) {
4164 found = add_rec_by_index(hash, &func_g, clear_filter);
4168 do_for_each_ftrace_rec(pg, rec) {
4170 if (rec->flags & FTRACE_FL_DISABLED)
4173 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
4174 ret = enter_record(hash, rec, clear_filter);
4181 } while_for_each_ftrace_rec();
4183 mutex_unlock(&ftrace_lock);
4189 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
4191 return match_records(hash, buff, len, NULL);
4194 static void ftrace_ops_update_code(struct ftrace_ops *ops,
4195 struct ftrace_ops_hash *old_hash)
4197 struct ftrace_ops *op;
4199 if (!ftrace_enabled)
4202 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4203 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4208 * If this is the shared global_ops filter, then we need to
4209 * check if there is another ops that shares it, is enabled.
4210 * If so, we still need to run the modify code.
4212 if (ops->func_hash != &global_ops.local_hash)
4215 do_for_each_ftrace_op(op, ftrace_ops_list) {
4216 if (op->func_hash == &global_ops.local_hash &&
4217 op->flags & FTRACE_OPS_FL_ENABLED) {
4218 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4219 /* Only need to do this once */
4222 } while_for_each_ftrace_op(op);
4225 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
4226 struct ftrace_hash **orig_hash,
4227 struct ftrace_hash *hash,
4230 struct ftrace_ops_hash old_hash_ops;
4231 struct ftrace_hash *old_hash;
4234 old_hash = *orig_hash;
4235 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4236 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4237 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4239 ftrace_ops_update_code(ops, &old_hash_ops);
4240 free_ftrace_hash_rcu(old_hash);
4245 static bool module_exists(const char *module)
4247 /* All modules have the symbol __this_module */
4248 static const char this_mod[] = "__this_module";
4249 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
4253 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
4255 if (n > sizeof(modname) - 1)
4258 val = module_kallsyms_lookup_name(modname);
4262 static int cache_mod(struct trace_array *tr,
4263 const char *func, char *module, int enable)
4265 struct ftrace_mod_load *ftrace_mod, *n;
4266 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4269 mutex_lock(&ftrace_lock);
4271 /* We do not cache inverse filters */
4272 if (func[0] == '!') {
4276 /* Look to remove this hash */
4277 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4278 if (strcmp(ftrace_mod->module, module) != 0)
4281 /* no func matches all */
4282 if (strcmp(func, "*") == 0 ||
4283 (ftrace_mod->func &&
4284 strcmp(ftrace_mod->func, func) == 0)) {
4286 free_ftrace_mod(ftrace_mod);
4294 /* We only care about modules that have not been loaded yet */
4295 if (module_exists(module))
4298 /* Save this string off, and execute it when the module is loaded */
4299 ret = ftrace_add_mod(tr, func, module, enable);
4301 mutex_unlock(&ftrace_lock);
4307 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4308 int reset, int enable);
4310 #ifdef CONFIG_MODULES
4311 static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4312 char *mod, bool enable)
4314 struct ftrace_mod_load *ftrace_mod, *n;
4315 struct ftrace_hash **orig_hash, *new_hash;
4316 LIST_HEAD(process_mods);
4319 mutex_lock(&ops->func_hash->regex_lock);
4322 orig_hash = &ops->func_hash->filter_hash;
4324 orig_hash = &ops->func_hash->notrace_hash;
4326 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4329 goto out; /* warn? */
4331 mutex_lock(&ftrace_lock);
4333 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4335 if (strcmp(ftrace_mod->module, mod) != 0)
4338 if (ftrace_mod->func)
4339 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4341 func = kstrdup("*", GFP_KERNEL);
4343 if (!func) /* warn? */
4346 list_move(&ftrace_mod->list, &process_mods);
4348 /* Use the newly allocated func, as it may be "*" */
4349 kfree(ftrace_mod->func);
4350 ftrace_mod->func = func;
4353 mutex_unlock(&ftrace_lock);
4355 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4357 func = ftrace_mod->func;
4359 /* Grabs ftrace_lock, which is why we have this extra step */
4360 match_records(new_hash, func, strlen(func), mod);
4361 free_ftrace_mod(ftrace_mod);
4364 if (enable && list_empty(head))
4365 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4367 mutex_lock(&ftrace_lock);
4369 ftrace_hash_move_and_update_ops(ops, orig_hash,
4371 mutex_unlock(&ftrace_lock);
4374 mutex_unlock(&ops->func_hash->regex_lock);
4376 free_ftrace_hash(new_hash);
4379 static void process_cached_mods(const char *mod_name)
4381 struct trace_array *tr;
4384 mod = kstrdup(mod_name, GFP_KERNEL);
4388 mutex_lock(&trace_types_lock);
4389 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4390 if (!list_empty(&tr->mod_trace))
4391 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4392 if (!list_empty(&tr->mod_notrace))
4393 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4395 mutex_unlock(&trace_types_lock);
4402 * We register the module command as a template to show others how
4403 * to register the a command as well.
4407 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4408 char *func_orig, char *cmd, char *module, int enable)
4413 /* match_records() modifies func, and we need the original */
4414 func = kstrdup(func_orig, GFP_KERNEL);
4419 * cmd == 'mod' because we only registered this func
4420 * for the 'mod' ftrace_func_command.
4421 * But if you register one func with multiple commands,
4422 * you can tell which command was used by the cmd
4425 ret = match_records(hash, func, strlen(func), module);
4429 return cache_mod(tr, func_orig, module, enable);
4435 static struct ftrace_func_command ftrace_mod_cmd = {
4437 .func = ftrace_mod_callback,
4440 static int __init ftrace_mod_cmd_init(void)
4442 return register_ftrace_command(&ftrace_mod_cmd);
4444 core_initcall(ftrace_mod_cmd_init);
4446 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4447 struct ftrace_ops *op, struct ftrace_regs *fregs)
4449 struct ftrace_probe_ops *probe_ops;
4450 struct ftrace_func_probe *probe;
4452 probe = container_of(op, struct ftrace_func_probe, ops);
4453 probe_ops = probe->probe_ops;
4456 * Disable preemption for these calls to prevent a RCU grace
4457 * period. This syncs the hash iteration and freeing of items
4458 * on the hash. rcu_read_lock is too dangerous here.
4460 preempt_disable_notrace();
4461 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4462 preempt_enable_notrace();
4465 struct ftrace_func_map {
4466 struct ftrace_func_entry entry;
4470 struct ftrace_func_mapper {
4471 struct ftrace_hash hash;
4475 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4477 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4479 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4481 struct ftrace_hash *hash;
4484 * The mapper is simply a ftrace_hash, but since the entries
4485 * in the hash are not ftrace_func_entry type, we define it
4486 * as a separate structure.
4488 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4489 return (struct ftrace_func_mapper *)hash;
4493 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4494 * @mapper: The mapper that has the ip maps
4495 * @ip: the instruction pointer to find the data for
4497 * Returns the data mapped to @ip if found otherwise NULL. The return
4498 * is actually the address of the mapper data pointer. The address is
4499 * returned for use cases where the data is no bigger than a long, and
4500 * the user can use the data pointer as its data instead of having to
4501 * allocate more memory for the reference.
4503 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4506 struct ftrace_func_entry *entry;
4507 struct ftrace_func_map *map;
4509 entry = ftrace_lookup_ip(&mapper->hash, ip);
4513 map = (struct ftrace_func_map *)entry;
4518 * ftrace_func_mapper_add_ip - Map some data to an ip
4519 * @mapper: The mapper that has the ip maps
4520 * @ip: The instruction pointer address to map @data to
4521 * @data: The data to map to @ip
4523 * Returns 0 on success otherwise an error.
4525 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4526 unsigned long ip, void *data)
4528 struct ftrace_func_entry *entry;
4529 struct ftrace_func_map *map;
4531 entry = ftrace_lookup_ip(&mapper->hash, ip);
4535 map = kmalloc(sizeof(*map), GFP_KERNEL);
4542 __add_hash_entry(&mapper->hash, &map->entry);
4548 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4549 * @mapper: The mapper that has the ip maps
4550 * @ip: The instruction pointer address to remove the data from
4552 * Returns the data if it is found, otherwise NULL.
4553 * Note, if the data pointer is used as the data itself, (see
4554 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4555 * if the data pointer was set to zero.
4557 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4560 struct ftrace_func_entry *entry;
4561 struct ftrace_func_map *map;
4564 entry = ftrace_lookup_ip(&mapper->hash, ip);
4568 map = (struct ftrace_func_map *)entry;
4571 remove_hash_entry(&mapper->hash, entry);
4578 * free_ftrace_func_mapper - free a mapping of ips and data
4579 * @mapper: The mapper that has the ip maps
4580 * @free_func: A function to be called on each data item.
4582 * This is used to free the function mapper. The @free_func is optional
4583 * and can be used if the data needs to be freed as well.
4585 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4586 ftrace_mapper_func free_func)
4588 struct ftrace_func_entry *entry;
4589 struct ftrace_func_map *map;
4590 struct hlist_head *hhd;
4596 if (free_func && mapper->hash.count) {
4597 size = 1 << mapper->hash.size_bits;
4598 for (i = 0; i < size; i++) {
4599 hhd = &mapper->hash.buckets[i];
4600 hlist_for_each_entry(entry, hhd, hlist) {
4601 map = (struct ftrace_func_map *)entry;
4606 free_ftrace_hash(&mapper->hash);
4609 static void release_probe(struct ftrace_func_probe *probe)
4611 struct ftrace_probe_ops *probe_ops;
4613 mutex_lock(&ftrace_lock);
4615 WARN_ON(probe->ref <= 0);
4617 /* Subtract the ref that was used to protect this instance */
4621 probe_ops = probe->probe_ops;
4623 * Sending zero as ip tells probe_ops to free
4624 * the probe->data itself
4626 if (probe_ops->free)
4627 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4628 list_del(&probe->list);
4631 mutex_unlock(&ftrace_lock);
4634 static void acquire_probe_locked(struct ftrace_func_probe *probe)
4637 * Add one ref to keep it from being freed when releasing the
4638 * ftrace_lock mutex.
4644 register_ftrace_function_probe(char *glob, struct trace_array *tr,
4645 struct ftrace_probe_ops *probe_ops,
4648 struct ftrace_func_probe *probe = NULL, *iter;
4649 struct ftrace_func_entry *entry;
4650 struct ftrace_hash **orig_hash;
4651 struct ftrace_hash *old_hash;
4652 struct ftrace_hash *hash;
4661 /* We do not support '!' for function probes */
4662 if (WARN_ON(glob[0] == '!'))
4666 mutex_lock(&ftrace_lock);
4667 /* Check if the probe_ops is already registered */
4668 list_for_each_entry(iter, &tr->func_probes, list) {
4669 if (iter->probe_ops == probe_ops) {
4675 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4677 mutex_unlock(&ftrace_lock);
4680 probe->probe_ops = probe_ops;
4681 probe->ops.func = function_trace_probe_call;
4683 ftrace_ops_init(&probe->ops);
4684 list_add(&probe->list, &tr->func_probes);
4687 acquire_probe_locked(probe);
4689 mutex_unlock(&ftrace_lock);
4692 * Note, there's a small window here that the func_hash->filter_hash
4693 * may be NULL or empty. Need to be careful when reading the loop.
4695 mutex_lock(&probe->ops.func_hash->regex_lock);
4697 orig_hash = &probe->ops.func_hash->filter_hash;
4698 old_hash = *orig_hash;
4699 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4706 ret = ftrace_match_records(hash, glob, strlen(glob));
4708 /* Nothing found? */
4715 size = 1 << hash->size_bits;
4716 for (i = 0; i < size; i++) {
4717 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4718 if (ftrace_lookup_ip(old_hash, entry->ip))
4721 * The caller might want to do something special
4722 * for each function we find. We call the callback
4723 * to give the caller an opportunity to do so.
4725 if (probe_ops->init) {
4726 ret = probe_ops->init(probe_ops, tr,
4730 if (probe_ops->free && count)
4731 probe_ops->free(probe_ops, tr,
4741 mutex_lock(&ftrace_lock);
4744 /* Nothing was added? */
4749 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4754 /* One ref for each new function traced */
4755 probe->ref += count;
4757 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4758 ret = ftrace_startup(&probe->ops, 0);
4761 mutex_unlock(&ftrace_lock);
4766 mutex_unlock(&probe->ops.func_hash->regex_lock);
4767 free_ftrace_hash(hash);
4769 release_probe(probe);
4774 if (!probe_ops->free || !count)
4777 /* Failed to do the move, need to call the free functions */
4778 for (i = 0; i < size; i++) {
4779 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4780 if (ftrace_lookup_ip(old_hash, entry->ip))
4782 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4789 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4790 struct ftrace_probe_ops *probe_ops)
4792 struct ftrace_func_probe *probe = NULL, *iter;
4793 struct ftrace_ops_hash old_hash_ops;
4794 struct ftrace_func_entry *entry;
4795 struct ftrace_glob func_g;
4796 struct ftrace_hash **orig_hash;
4797 struct ftrace_hash *old_hash;
4798 struct ftrace_hash *hash = NULL;
4799 struct hlist_node *tmp;
4800 struct hlist_head hhd;
4801 char str[KSYM_SYMBOL_LEN];
4803 int i, ret = -ENODEV;
4806 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4807 func_g.search = NULL;
4811 func_g.type = filter_parse_regex(glob, strlen(glob),
4812 &func_g.search, ¬);
4813 func_g.len = strlen(func_g.search);
4815 /* we do not support '!' for function probes */
4820 mutex_lock(&ftrace_lock);
4821 /* Check if the probe_ops is already registered */
4822 list_for_each_entry(iter, &tr->func_probes, list) {
4823 if (iter->probe_ops == probe_ops) {
4829 goto err_unlock_ftrace;
4832 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4833 goto err_unlock_ftrace;
4835 acquire_probe_locked(probe);
4837 mutex_unlock(&ftrace_lock);
4839 mutex_lock(&probe->ops.func_hash->regex_lock);
4841 orig_hash = &probe->ops.func_hash->filter_hash;
4842 old_hash = *orig_hash;
4844 if (ftrace_hash_empty(old_hash))
4847 old_hash_ops.filter_hash = old_hash;
4848 /* Probes only have filters */
4849 old_hash_ops.notrace_hash = NULL;
4852 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4856 INIT_HLIST_HEAD(&hhd);
4858 size = 1 << hash->size_bits;
4859 for (i = 0; i < size; i++) {
4860 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4862 if (func_g.search) {
4863 kallsyms_lookup(entry->ip, NULL, NULL,
4865 if (!ftrace_match(str, &func_g))
4869 remove_hash_entry(hash, entry);
4870 hlist_add_head(&entry->hlist, &hhd);
4874 /* Nothing found? */
4880 mutex_lock(&ftrace_lock);
4882 WARN_ON(probe->ref < count);
4884 probe->ref -= count;
4886 if (ftrace_hash_empty(hash))
4887 ftrace_shutdown(&probe->ops, 0);
4889 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4892 /* still need to update the function call sites */
4893 if (ftrace_enabled && !ftrace_hash_empty(hash))
4894 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4898 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4899 hlist_del(&entry->hlist);
4900 if (probe_ops->free)
4901 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4904 mutex_unlock(&ftrace_lock);
4907 mutex_unlock(&probe->ops.func_hash->regex_lock);
4908 free_ftrace_hash(hash);
4910 release_probe(probe);
4915 mutex_unlock(&ftrace_lock);
4919 void clear_ftrace_function_probes(struct trace_array *tr)
4921 struct ftrace_func_probe *probe, *n;
4923 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4924 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
4927 static LIST_HEAD(ftrace_commands);
4928 static DEFINE_MUTEX(ftrace_cmd_mutex);
4931 * Currently we only register ftrace commands from __init, so mark this
4934 __init int register_ftrace_command(struct ftrace_func_command *cmd)
4936 struct ftrace_func_command *p;
4939 mutex_lock(&ftrace_cmd_mutex);
4940 list_for_each_entry(p, &ftrace_commands, list) {
4941 if (strcmp(cmd->name, p->name) == 0) {
4946 list_add(&cmd->list, &ftrace_commands);
4948 mutex_unlock(&ftrace_cmd_mutex);
4954 * Currently we only unregister ftrace commands from __init, so mark
4957 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4959 struct ftrace_func_command *p, *n;
4962 mutex_lock(&ftrace_cmd_mutex);
4963 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4964 if (strcmp(cmd->name, p->name) == 0) {
4966 list_del_init(&p->list);
4971 mutex_unlock(&ftrace_cmd_mutex);
4976 static int ftrace_process_regex(struct ftrace_iterator *iter,
4977 char *buff, int len, int enable)
4979 struct ftrace_hash *hash = iter->hash;
4980 struct trace_array *tr = iter->ops->private;
4981 char *func, *command, *next = buff;
4982 struct ftrace_func_command *p;
4985 func = strsep(&next, ":");
4988 ret = ftrace_match_records(hash, func, len);
4998 command = strsep(&next, ":");
5000 mutex_lock(&ftrace_cmd_mutex);
5001 list_for_each_entry(p, &ftrace_commands, list) {
5002 if (strcmp(p->name, command) == 0) {
5003 ret = p->func(tr, hash, func, command, next, enable);
5008 mutex_unlock(&ftrace_cmd_mutex);
5014 ftrace_regex_write(struct file *file, const char __user *ubuf,
5015 size_t cnt, loff_t *ppos, int enable)
5017 struct ftrace_iterator *iter;
5018 struct trace_parser *parser;
5024 if (file->f_mode & FMODE_READ) {
5025 struct seq_file *m = file->private_data;
5028 iter = file->private_data;
5030 if (unlikely(ftrace_disabled))
5033 /* iter->hash is a local copy, so we don't need regex_lock */
5035 parser = &iter->parser;
5036 read = trace_get_user(parser, ubuf, cnt, ppos);
5038 if (read >= 0 && trace_parser_loaded(parser) &&
5039 !trace_parser_cont(parser)) {
5040 ret = ftrace_process_regex(iter, parser->buffer,
5041 parser->idx, enable);
5042 trace_parser_clear(parser);
5053 ftrace_filter_write(struct file *file, const char __user *ubuf,
5054 size_t cnt, loff_t *ppos)
5056 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
5060 ftrace_notrace_write(struct file *file, const char __user *ubuf,
5061 size_t cnt, loff_t *ppos)
5063 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
5067 __ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
5069 struct ftrace_func_entry *entry;
5071 ip = ftrace_location(ip);
5076 entry = ftrace_lookup_ip(hash, ip);
5079 free_hash_entry(hash, entry);
5083 return add_hash_entry(hash, ip);
5087 ftrace_match_addr(struct ftrace_hash *hash, unsigned long *ips,
5088 unsigned int cnt, int remove)
5093 for (i = 0; i < cnt; i++) {
5094 err = __ftrace_match_addr(hash, ips[i], remove);
5097 * This expects the @hash is a temporary hash and if this
5098 * fails the caller must free the @hash.
5107 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
5108 unsigned long *ips, unsigned int cnt,
5109 int remove, int reset, int enable)
5111 struct ftrace_hash **orig_hash;
5112 struct ftrace_hash *hash;
5115 if (unlikely(ftrace_disabled))
5118 mutex_lock(&ops->func_hash->regex_lock);
5121 orig_hash = &ops->func_hash->filter_hash;
5123 orig_hash = &ops->func_hash->notrace_hash;
5126 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5128 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
5132 goto out_regex_unlock;
5135 if (buf && !ftrace_match_records(hash, buf, len)) {
5137 goto out_regex_unlock;
5140 ret = ftrace_match_addr(hash, ips, cnt, remove);
5142 goto out_regex_unlock;
5145 mutex_lock(&ftrace_lock);
5146 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
5147 mutex_unlock(&ftrace_lock);
5150 mutex_unlock(&ops->func_hash->regex_lock);
5152 free_ftrace_hash(hash);
5157 ftrace_set_addr(struct ftrace_ops *ops, unsigned long *ips, unsigned int cnt,
5158 int remove, int reset, int enable)
5160 return ftrace_set_hash(ops, NULL, 0, ips, cnt, remove, reset, enable);
5163 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
5165 struct ftrace_direct_func {
5166 struct list_head next;
5171 static LIST_HEAD(ftrace_direct_funcs);
5174 * ftrace_find_direct_func - test an address if it is a registered direct caller
5175 * @addr: The address of a registered direct caller
5177 * This searches to see if a ftrace direct caller has been registered
5178 * at a specific address, and if so, it returns a descriptor for it.
5180 * This can be used by architecture code to see if an address is
5181 * a direct caller (trampoline) attached to a fentry/mcount location.
5182 * This is useful for the function_graph tracer, as it may need to
5183 * do adjustments if it traced a location that also has a direct
5184 * trampoline attached to it.
5186 struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
5188 struct ftrace_direct_func *entry;
5191 /* May be called by fgraph trampoline (protected by rcu tasks) */
5192 list_for_each_entry_rcu(entry, &ftrace_direct_funcs, next) {
5193 if (entry->addr == addr) {
5204 static struct ftrace_direct_func *ftrace_alloc_direct_func(unsigned long addr)
5206 struct ftrace_direct_func *direct;
5208 direct = kmalloc(sizeof(*direct), GFP_KERNEL);
5211 direct->addr = addr;
5213 list_add_rcu(&direct->next, &ftrace_direct_funcs);
5214 ftrace_direct_func_count++;
5219 * register_ftrace_direct - Call a custom trampoline directly
5220 * @ip: The address of the nop at the beginning of a function
5221 * @addr: The address of the trampoline to call at @ip
5223 * This is used to connect a direct call from the nop location (@ip)
5224 * at the start of ftrace traced functions. The location that it calls
5225 * (@addr) must be able to handle a direct call, and save the parameters
5226 * of the function being traced, and restore them (or inject new ones
5227 * if needed), before returning.
5231 * -EBUSY - Another direct function is already attached (there can be only one)
5232 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
5233 * -ENOMEM - There was an allocation failure.
5235 int register_ftrace_direct(unsigned long ip, unsigned long addr)
5237 struct ftrace_direct_func *direct;
5238 struct ftrace_func_entry *entry;
5239 struct ftrace_hash *free_hash = NULL;
5240 struct dyn_ftrace *rec;
5243 mutex_lock(&direct_mutex);
5245 ip = ftrace_location(ip);
5249 /* See if there's a direct function at @ip already */
5251 if (ftrace_find_rec_direct(ip))
5255 rec = lookup_rec(ip, ip);
5260 * Check if the rec says it has a direct call but we didn't
5263 if (WARN_ON(rec->flags & FTRACE_FL_DIRECT))
5266 /* Make sure the ip points to the exact record */
5267 if (ip != rec->ip) {
5269 /* Need to check this ip for a direct. */
5270 if (ftrace_find_rec_direct(ip))
5275 direct = ftrace_find_direct_func(addr);
5277 direct = ftrace_alloc_direct_func(addr);
5282 entry = ftrace_add_rec_direct(ip, addr, &free_hash);
5286 ret = ftrace_set_filter_ip(&direct_ops, ip, 0, 0);
5288 if (!ret && !(direct_ops.flags & FTRACE_OPS_FL_ENABLED)) {
5289 ret = register_ftrace_function(&direct_ops);
5291 ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5295 remove_hash_entry(direct_functions, entry);
5297 if (!direct->count) {
5298 list_del_rcu(&direct->next);
5299 synchronize_rcu_tasks();
5302 free_ftrace_hash(free_hash);
5304 ftrace_direct_func_count--;
5310 mutex_unlock(&direct_mutex);
5313 synchronize_rcu_tasks();
5314 free_ftrace_hash(free_hash);
5319 EXPORT_SYMBOL_GPL(register_ftrace_direct);
5321 static struct ftrace_func_entry *find_direct_entry(unsigned long *ip,
5322 struct dyn_ftrace **recp)
5324 struct ftrace_func_entry *entry;
5325 struct dyn_ftrace *rec;
5327 rec = lookup_rec(*ip, *ip);
5331 entry = __ftrace_lookup_ip(direct_functions, rec->ip);
5333 WARN_ON(rec->flags & FTRACE_FL_DIRECT);
5337 WARN_ON(!(rec->flags & FTRACE_FL_DIRECT));
5339 /* Passed in ip just needs to be on the call site */
5348 int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
5350 struct ftrace_direct_func *direct;
5351 struct ftrace_func_entry *entry;
5352 struct ftrace_hash *hash;
5355 mutex_lock(&direct_mutex);
5357 ip = ftrace_location(ip);
5361 entry = find_direct_entry(&ip, NULL);
5365 hash = direct_ops.func_hash->filter_hash;
5366 if (hash->count == 1)
5367 unregister_ftrace_function(&direct_ops);
5369 ret = ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5373 remove_hash_entry(direct_functions, entry);
5375 direct = ftrace_find_direct_func(addr);
5376 if (!WARN_ON(!direct)) {
5377 /* This is the good path (see the ! before WARN) */
5379 WARN_ON(direct->count < 0);
5380 if (!direct->count) {
5381 list_del_rcu(&direct->next);
5382 synchronize_rcu_tasks();
5385 ftrace_direct_func_count--;
5389 mutex_unlock(&direct_mutex);
5393 EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
5395 static struct ftrace_ops stub_ops = {
5396 .func = ftrace_stub,
5400 * ftrace_modify_direct_caller - modify ftrace nop directly
5401 * @entry: The ftrace hash entry of the direct helper for @rec
5402 * @rec: The record representing the function site to patch
5403 * @old_addr: The location that the site at @rec->ip currently calls
5404 * @new_addr: The location that the site at @rec->ip should call
5406 * An architecture may overwrite this function to optimize the
5407 * changing of the direct callback on an ftrace nop location.
5408 * This is called with the ftrace_lock mutex held, and no other
5409 * ftrace callbacks are on the associated record (@rec). Thus,
5410 * it is safe to modify the ftrace record, where it should be
5411 * currently calling @old_addr directly, to call @new_addr.
5413 * Safety checks should be made to make sure that the code at
5414 * @rec->ip is currently calling @old_addr. And this must
5415 * also update entry->direct to @new_addr.
5417 int __weak ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
5418 struct dyn_ftrace *rec,
5419 unsigned long old_addr,
5420 unsigned long new_addr)
5422 unsigned long ip = rec->ip;
5426 * The ftrace_lock was used to determine if the record
5427 * had more than one registered user to it. If it did,
5428 * we needed to prevent that from changing to do the quick
5429 * switch. But if it did not (only a direct caller was attached)
5430 * then this function is called. But this function can deal
5431 * with attached callers to the rec that we care about, and
5432 * since this function uses standard ftrace calls that take
5433 * the ftrace_lock mutex, we need to release it.
5435 mutex_unlock(&ftrace_lock);
5438 * By setting a stub function at the same address, we force
5439 * the code to call the iterator and the direct_ops helper.
5440 * This means that @ip does not call the direct call, and
5441 * we can simply modify it.
5443 ret = ftrace_set_filter_ip(&stub_ops, ip, 0, 0);
5447 ret = register_ftrace_function(&stub_ops);
5449 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5453 entry->direct = new_addr;
5456 * By removing the stub, we put back the direct call, calling
5459 unregister_ftrace_function(&stub_ops);
5460 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5463 mutex_lock(&ftrace_lock);
5469 * modify_ftrace_direct - Modify an existing direct call to call something else
5470 * @ip: The instruction pointer to modify
5471 * @old_addr: The address that the current @ip calls directly
5472 * @new_addr: The address that the @ip should call
5474 * This modifies a ftrace direct caller at an instruction pointer without
5475 * having to disable it first. The direct call will switch over to the
5476 * @new_addr without missing anything.
5478 * Returns: zero on success. Non zero on error, which includes:
5479 * -ENODEV : the @ip given has no direct caller attached
5480 * -EINVAL : the @old_addr does not match the current direct caller
5482 int modify_ftrace_direct(unsigned long ip,
5483 unsigned long old_addr, unsigned long new_addr)
5485 struct ftrace_direct_func *direct, *new_direct = NULL;
5486 struct ftrace_func_entry *entry;
5487 struct dyn_ftrace *rec;
5490 mutex_lock(&direct_mutex);
5492 mutex_lock(&ftrace_lock);
5494 ip = ftrace_location(ip);
5498 entry = find_direct_entry(&ip, &rec);
5503 if (entry->direct != old_addr)
5506 direct = ftrace_find_direct_func(old_addr);
5507 if (WARN_ON(!direct))
5509 if (direct->count > 1) {
5511 new_direct = ftrace_alloc_direct_func(new_addr);
5515 new_direct->count++;
5517 direct->addr = new_addr;
5521 * If there's no other ftrace callback on the rec->ip location,
5522 * then it can be changed directly by the architecture.
5523 * If there is another caller, then we just need to change the
5524 * direct caller helper to point to @new_addr.
5526 if (ftrace_rec_count(rec) == 1) {
5527 ret = ftrace_modify_direct_caller(entry, rec, old_addr, new_addr);
5529 entry->direct = new_addr;
5533 if (unlikely(ret && new_direct)) {
5535 list_del_rcu(&new_direct->next);
5536 synchronize_rcu_tasks();
5538 ftrace_direct_func_count--;
5542 mutex_unlock(&ftrace_lock);
5543 mutex_unlock(&direct_mutex);
5546 EXPORT_SYMBOL_GPL(modify_ftrace_direct);
5548 #define MULTI_FLAGS (FTRACE_OPS_FL_IPMODIFY | FTRACE_OPS_FL_DIRECT | \
5549 FTRACE_OPS_FL_SAVE_REGS)
5551 static int check_direct_multi(struct ftrace_ops *ops)
5553 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5555 if ((ops->flags & MULTI_FLAGS) != MULTI_FLAGS)
5560 static void remove_direct_functions_hash(struct ftrace_hash *hash, unsigned long addr)
5562 struct ftrace_func_entry *entry, *del;
5565 size = 1 << hash->size_bits;
5566 for (i = 0; i < size; i++) {
5567 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5568 del = __ftrace_lookup_ip(direct_functions, entry->ip);
5569 if (del && del->direct == addr) {
5570 remove_hash_entry(direct_functions, del);
5578 * register_ftrace_direct_multi - Call a custom trampoline directly
5579 * for multiple functions registered in @ops
5580 * @ops: The address of the struct ftrace_ops object
5581 * @addr: The address of the trampoline to call at @ops functions
5583 * This is used to connect a direct calls to @addr from the nop locations
5584 * of the functions registered in @ops (with by ftrace_set_filter_ip
5587 * The location that it calls (@addr) must be able to handle a direct call,
5588 * and save the parameters of the function being traced, and restore them
5589 * (or inject new ones if needed), before returning.
5593 * -EINVAL - The @ops object was already registered with this call or
5594 * when there are no functions in @ops object.
5595 * -EBUSY - Another direct function is already attached (there can be only one)
5596 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
5597 * -ENOMEM - There was an allocation failure.
5599 int register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
5601 struct ftrace_hash *hash, *free_hash = NULL;
5602 struct ftrace_func_entry *entry, *new;
5603 int err = -EBUSY, size, i;
5605 if (ops->func || ops->trampoline)
5607 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5609 if (ops->flags & FTRACE_OPS_FL_ENABLED)
5612 hash = ops->func_hash->filter_hash;
5613 if (ftrace_hash_empty(hash))
5616 mutex_lock(&direct_mutex);
5618 /* Make sure requested entries are not already registered.. */
5619 size = 1 << hash->size_bits;
5620 for (i = 0; i < size; i++) {
5621 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5622 if (ftrace_find_rec_direct(entry->ip))
5627 /* ... and insert them to direct_functions hash. */
5629 for (i = 0; i < size; i++) {
5630 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5631 new = ftrace_add_rec_direct(entry->ip, addr, &free_hash);
5634 entry->direct = addr;
5638 ops->func = call_direct_funcs;
5639 ops->flags = MULTI_FLAGS;
5640 ops->trampoline = FTRACE_REGS_ADDR;
5642 err = register_ftrace_function(ops);
5646 remove_direct_functions_hash(hash, addr);
5649 mutex_unlock(&direct_mutex);
5652 synchronize_rcu_tasks();
5653 free_ftrace_hash(free_hash);
5657 EXPORT_SYMBOL_GPL(register_ftrace_direct_multi);
5660 * unregister_ftrace_direct_multi - Remove calls to custom trampoline
5661 * previously registered by register_ftrace_direct_multi for @ops object.
5662 * @ops: The address of the struct ftrace_ops object
5664 * This is used to remove a direct calls to @addr from the nop locations
5665 * of the functions registered in @ops (with by ftrace_set_filter_ip
5670 * -EINVAL - The @ops object was not properly registered.
5672 int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
5674 struct ftrace_hash *hash = ops->func_hash->filter_hash;
5677 if (check_direct_multi(ops))
5679 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5682 mutex_lock(&direct_mutex);
5683 err = unregister_ftrace_function(ops);
5684 remove_direct_functions_hash(hash, addr);
5685 mutex_unlock(&direct_mutex);
5687 /* cleanup for possible another register call */
5689 ops->trampoline = 0;
5692 EXPORT_SYMBOL_GPL(unregister_ftrace_direct_multi);
5695 * modify_ftrace_direct_multi - Modify an existing direct 'multi' call
5696 * to call something else
5697 * @ops: The address of the struct ftrace_ops object
5698 * @addr: The address of the new trampoline to call at @ops functions
5700 * This is used to unregister currently registered direct caller and
5701 * register new one @addr on functions registered in @ops object.
5703 * Note there's window between ftrace_shutdown and ftrace_startup calls
5704 * where there will be no callbacks called.
5706 * Returns: zero on success. Non zero on error, which includes:
5707 * -EINVAL - The @ops object was not properly registered.
5709 int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
5711 struct ftrace_hash *hash;
5712 struct ftrace_func_entry *entry, *iter;
5713 static struct ftrace_ops tmp_ops = {
5714 .func = ftrace_stub,
5715 .flags = FTRACE_OPS_FL_STUB,
5720 if (check_direct_multi(ops))
5722 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5725 mutex_lock(&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(&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);
5758 mutex_unlock(&direct_mutex);
5761 EXPORT_SYMBOL_GPL(modify_ftrace_direct_multi);
5762 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
5765 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
5766 * @ops - the ops to set the filter with
5767 * @ip - the address to add to or remove from the filter.
5768 * @remove - non zero to remove the ip from the filter
5769 * @reset - non zero to reset all filters before applying this filter.
5771 * Filters denote which functions should be enabled when tracing is enabled
5772 * If @ip is NULL, it fails to update filter.
5774 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
5775 int remove, int reset)
5777 ftrace_ops_init(ops);
5778 return ftrace_set_addr(ops, &ip, 1, remove, reset, 1);
5780 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
5783 * ftrace_set_filter_ips - set functions to filter on in ftrace by addresses
5784 * @ops - the ops to set the filter with
5785 * @ips - the array of addresses to add to or remove from the filter.
5786 * @cnt - the number of addresses in @ips
5787 * @remove - non zero to remove ips from the filter
5788 * @reset - non zero to reset all filters before applying this filter.
5790 * Filters denote which functions should be enabled when tracing is enabled
5791 * If @ips array or any ip specified within is NULL , it fails to update filter.
5793 int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips,
5794 unsigned int cnt, int remove, int reset)
5796 ftrace_ops_init(ops);
5797 return ftrace_set_addr(ops, ips, cnt, remove, reset, 1);
5799 EXPORT_SYMBOL_GPL(ftrace_set_filter_ips);
5802 * ftrace_ops_set_global_filter - setup ops to use global filters
5803 * @ops - the ops which will use the global filters
5805 * ftrace users who need global function trace filtering should call this.
5806 * It can set the global filter only if ops were not initialized before.
5808 void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
5810 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
5813 ftrace_ops_init(ops);
5814 ops->func_hash = &global_ops.local_hash;
5816 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
5819 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
5820 int reset, int enable)
5822 return ftrace_set_hash(ops, buf, len, NULL, 0, 0, reset, enable);
5826 * ftrace_set_filter - set a function to filter on in ftrace
5827 * @ops - the ops to set the filter with
5828 * @buf - the string that holds the function filter text.
5829 * @len - the length of the string.
5830 * @reset - non zero to reset all filters before applying this filter.
5832 * Filters denote which functions should be enabled when tracing is enabled.
5833 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5835 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
5838 ftrace_ops_init(ops);
5839 return ftrace_set_regex(ops, buf, len, reset, 1);
5841 EXPORT_SYMBOL_GPL(ftrace_set_filter);
5844 * ftrace_set_notrace - set a function to not trace in ftrace
5845 * @ops - the ops to set the notrace filter with
5846 * @buf - the string that holds the function notrace text.
5847 * @len - the length of the string.
5848 * @reset - non zero to reset all filters before applying this filter.
5850 * Notrace Filters denote which functions should not be enabled when tracing
5851 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5854 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
5857 ftrace_ops_init(ops);
5858 return ftrace_set_regex(ops, buf, len, reset, 0);
5860 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
5862 * ftrace_set_global_filter - set a function to filter on with global tracers
5863 * @buf - the string that holds the function filter text.
5864 * @len - the length of the string.
5865 * @reset - non zero to reset all filters before applying this filter.
5867 * Filters denote which functions should be enabled when tracing is enabled.
5868 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5870 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
5872 ftrace_set_regex(&global_ops, buf, len, reset, 1);
5874 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
5877 * ftrace_set_global_notrace - set a function to not trace with global tracers
5878 * @buf - the string that holds the function notrace text.
5879 * @len - the length of the string.
5880 * @reset - non zero to reset all filters before applying this filter.
5882 * Notrace Filters denote which functions should not be enabled when tracing
5883 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5886 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
5888 ftrace_set_regex(&global_ops, buf, len, reset, 0);
5890 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
5893 * command line interface to allow users to set filters on boot up.
5895 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
5896 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5897 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
5899 /* Used by function selftest to not test if filter is set */
5900 bool ftrace_filter_param __initdata;
5902 static int __init set_ftrace_notrace(char *str)
5904 ftrace_filter_param = true;
5905 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
5908 __setup("ftrace_notrace=", set_ftrace_notrace);
5910 static int __init set_ftrace_filter(char *str)
5912 ftrace_filter_param = true;
5913 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
5916 __setup("ftrace_filter=", set_ftrace_filter);
5918 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5919 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
5920 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5921 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
5923 static int __init set_graph_function(char *str)
5925 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
5928 __setup("ftrace_graph_filter=", set_graph_function);
5930 static int __init set_graph_notrace_function(char *str)
5932 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
5935 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
5937 static int __init set_graph_max_depth_function(char *str)
5941 fgraph_max_depth = simple_strtoul(str, NULL, 0);
5944 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
5946 static void __init set_ftrace_early_graph(char *buf, int enable)
5950 struct ftrace_hash *hash;
5952 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5953 if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
5957 func = strsep(&buf, ",");
5958 /* we allow only one expression at a time */
5959 ret = ftrace_graph_set_hash(hash, func);
5961 printk(KERN_DEBUG "ftrace: function %s not "
5962 "traceable\n", func);
5966 ftrace_graph_hash = hash;
5968 ftrace_graph_notrace_hash = hash;
5970 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5973 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
5977 ftrace_ops_init(ops);
5980 func = strsep(&buf, ",");
5981 ftrace_set_regex(ops, func, strlen(func), 0, enable);
5985 static void __init set_ftrace_early_filters(void)
5987 if (ftrace_filter_buf[0])
5988 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
5989 if (ftrace_notrace_buf[0])
5990 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
5991 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5992 if (ftrace_graph_buf[0])
5993 set_ftrace_early_graph(ftrace_graph_buf, 1);
5994 if (ftrace_graph_notrace_buf[0])
5995 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
5996 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5999 int ftrace_regex_release(struct inode *inode, struct file *file)
6001 struct seq_file *m = (struct seq_file *)file->private_data;
6002 struct ftrace_iterator *iter;
6003 struct ftrace_hash **orig_hash;
6004 struct trace_parser *parser;
6007 if (file->f_mode & FMODE_READ) {
6009 seq_release(inode, file);
6011 iter = file->private_data;
6013 parser = &iter->parser;
6014 if (trace_parser_loaded(parser)) {
6015 int enable = !(iter->flags & FTRACE_ITER_NOTRACE);
6017 ftrace_process_regex(iter, parser->buffer,
6018 parser->idx, enable);
6021 trace_parser_put(parser);
6023 mutex_lock(&iter->ops->func_hash->regex_lock);
6025 if (file->f_mode & FMODE_WRITE) {
6026 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
6029 orig_hash = &iter->ops->func_hash->filter_hash;
6030 if (iter->tr && !list_empty(&iter->tr->mod_trace))
6031 iter->hash->flags |= FTRACE_HASH_FL_MOD;
6033 orig_hash = &iter->ops->func_hash->notrace_hash;
6035 mutex_lock(&ftrace_lock);
6036 ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
6037 iter->hash, filter_hash);
6038 mutex_unlock(&ftrace_lock);
6040 /* For read only, the hash is the ops hash */
6044 mutex_unlock(&iter->ops->func_hash->regex_lock);
6045 free_ftrace_hash(iter->hash);
6047 trace_array_put(iter->tr);
6053 static const struct file_operations ftrace_avail_fops = {
6054 .open = ftrace_avail_open,
6056 .llseek = seq_lseek,
6057 .release = seq_release_private,
6060 static const struct file_operations ftrace_enabled_fops = {
6061 .open = ftrace_enabled_open,
6063 .llseek = seq_lseek,
6064 .release = seq_release_private,
6067 static const struct file_operations ftrace_filter_fops = {
6068 .open = ftrace_filter_open,
6070 .write = ftrace_filter_write,
6071 .llseek = tracing_lseek,
6072 .release = ftrace_regex_release,
6075 static const struct file_operations ftrace_notrace_fops = {
6076 .open = ftrace_notrace_open,
6078 .write = ftrace_notrace_write,
6079 .llseek = tracing_lseek,
6080 .release = ftrace_regex_release,
6083 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
6085 static DEFINE_MUTEX(graph_lock);
6087 struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
6088 struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
6090 enum graph_filter_type {
6091 GRAPH_FILTER_NOTRACE = 0,
6092 GRAPH_FILTER_FUNCTION,
6095 #define FTRACE_GRAPH_EMPTY ((void *)1)
6097 struct ftrace_graph_data {
6098 struct ftrace_hash *hash;
6099 struct ftrace_func_entry *entry;
6100 int idx; /* for hash table iteration */
6101 enum graph_filter_type type;
6102 struct ftrace_hash *new_hash;
6103 const struct seq_operations *seq_ops;
6104 struct trace_parser parser;
6108 __g_next(struct seq_file *m, loff_t *pos)
6110 struct ftrace_graph_data *fgd = m->private;
6111 struct ftrace_func_entry *entry = fgd->entry;
6112 struct hlist_head *head;
6113 int i, idx = fgd->idx;
6115 if (*pos >= fgd->hash->count)
6119 hlist_for_each_entry_continue(entry, hlist) {
6127 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
6128 head = &fgd->hash->buckets[i];
6129 hlist_for_each_entry(entry, head, hlist) {
6139 g_next(struct seq_file *m, void *v, loff_t *pos)
6142 return __g_next(m, pos);
6145 static void *g_start(struct seq_file *m, loff_t *pos)
6147 struct ftrace_graph_data *fgd = m->private;
6149 mutex_lock(&graph_lock);
6151 if (fgd->type == GRAPH_FILTER_FUNCTION)
6152 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6153 lockdep_is_held(&graph_lock));
6155 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6156 lockdep_is_held(&graph_lock));
6158 /* Nothing, tell g_show to print all functions are enabled */
6159 if (ftrace_hash_empty(fgd->hash) && !*pos)
6160 return FTRACE_GRAPH_EMPTY;
6164 return __g_next(m, pos);
6167 static void g_stop(struct seq_file *m, void *p)
6169 mutex_unlock(&graph_lock);
6172 static int g_show(struct seq_file *m, void *v)
6174 struct ftrace_func_entry *entry = v;
6179 if (entry == FTRACE_GRAPH_EMPTY) {
6180 struct ftrace_graph_data *fgd = m->private;
6182 if (fgd->type == GRAPH_FILTER_FUNCTION)
6183 seq_puts(m, "#### all functions enabled ####\n");
6185 seq_puts(m, "#### no functions disabled ####\n");
6189 seq_printf(m, "%ps\n", (void *)entry->ip);
6194 static const struct seq_operations ftrace_graph_seq_ops = {
6202 __ftrace_graph_open(struct inode *inode, struct file *file,
6203 struct ftrace_graph_data *fgd)
6206 struct ftrace_hash *new_hash = NULL;
6208 ret = security_locked_down(LOCKDOWN_TRACEFS);
6212 if (file->f_mode & FMODE_WRITE) {
6213 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
6215 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
6218 if (file->f_flags & O_TRUNC)
6219 new_hash = alloc_ftrace_hash(size_bits);
6221 new_hash = alloc_and_copy_ftrace_hash(size_bits,
6229 if (file->f_mode & FMODE_READ) {
6230 ret = seq_open(file, &ftrace_graph_seq_ops);
6232 struct seq_file *m = file->private_data;
6236 free_ftrace_hash(new_hash);
6240 file->private_data = fgd;
6243 if (ret < 0 && file->f_mode & FMODE_WRITE)
6244 trace_parser_put(&fgd->parser);
6246 fgd->new_hash = new_hash;
6249 * All uses of fgd->hash must be taken with the graph_lock
6250 * held. The graph_lock is going to be released, so force
6251 * fgd->hash to be reinitialized when it is taken again.
6259 ftrace_graph_open(struct inode *inode, struct file *file)
6261 struct ftrace_graph_data *fgd;
6264 if (unlikely(ftrace_disabled))
6267 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6271 mutex_lock(&graph_lock);
6273 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6274 lockdep_is_held(&graph_lock));
6275 fgd->type = GRAPH_FILTER_FUNCTION;
6276 fgd->seq_ops = &ftrace_graph_seq_ops;
6278 ret = __ftrace_graph_open(inode, file, fgd);
6282 mutex_unlock(&graph_lock);
6287 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
6289 struct ftrace_graph_data *fgd;
6292 if (unlikely(ftrace_disabled))
6295 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6299 mutex_lock(&graph_lock);
6301 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6302 lockdep_is_held(&graph_lock));
6303 fgd->type = GRAPH_FILTER_NOTRACE;
6304 fgd->seq_ops = &ftrace_graph_seq_ops;
6306 ret = __ftrace_graph_open(inode, file, fgd);
6310 mutex_unlock(&graph_lock);
6315 ftrace_graph_release(struct inode *inode, struct file *file)
6317 struct ftrace_graph_data *fgd;
6318 struct ftrace_hash *old_hash, *new_hash;
6319 struct trace_parser *parser;
6322 if (file->f_mode & FMODE_READ) {
6323 struct seq_file *m = file->private_data;
6326 seq_release(inode, file);
6328 fgd = file->private_data;
6332 if (file->f_mode & FMODE_WRITE) {
6334 parser = &fgd->parser;
6336 if (trace_parser_loaded((parser))) {
6337 ret = ftrace_graph_set_hash(fgd->new_hash,
6341 trace_parser_put(parser);
6343 new_hash = __ftrace_hash_move(fgd->new_hash);
6349 mutex_lock(&graph_lock);
6351 if (fgd->type == GRAPH_FILTER_FUNCTION) {
6352 old_hash = rcu_dereference_protected(ftrace_graph_hash,
6353 lockdep_is_held(&graph_lock));
6354 rcu_assign_pointer(ftrace_graph_hash, new_hash);
6356 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6357 lockdep_is_held(&graph_lock));
6358 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
6361 mutex_unlock(&graph_lock);
6364 * We need to do a hard force of sched synchronization.
6365 * This is because we use preempt_disable() to do RCU, but
6366 * the function tracers can be called where RCU is not watching
6367 * (like before user_exit()). We can not rely on the RCU
6368 * infrastructure to do the synchronization, thus we must do it
6371 if (old_hash != EMPTY_HASH)
6372 synchronize_rcu_tasks_rude();
6374 free_ftrace_hash(old_hash);
6378 free_ftrace_hash(fgd->new_hash);
6385 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
6387 struct ftrace_glob func_g;
6388 struct dyn_ftrace *rec;
6389 struct ftrace_page *pg;
6390 struct ftrace_func_entry *entry;
6395 func_g.type = filter_parse_regex(buffer, strlen(buffer),
6396 &func_g.search, ¬);
6398 func_g.len = strlen(func_g.search);
6400 mutex_lock(&ftrace_lock);
6402 if (unlikely(ftrace_disabled)) {
6403 mutex_unlock(&ftrace_lock);
6407 do_for_each_ftrace_rec(pg, rec) {
6409 if (rec->flags & FTRACE_FL_DISABLED)
6412 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
6413 entry = ftrace_lookup_ip(hash, rec->ip);
6420 if (add_hash_entry(hash, rec->ip) < 0)
6424 free_hash_entry(hash, entry);
6429 } while_for_each_ftrace_rec();
6431 mutex_unlock(&ftrace_lock);
6440 ftrace_graph_write(struct file *file, const char __user *ubuf,
6441 size_t cnt, loff_t *ppos)
6443 ssize_t read, ret = 0;
6444 struct ftrace_graph_data *fgd = file->private_data;
6445 struct trace_parser *parser;
6450 /* Read mode uses seq functions */
6451 if (file->f_mode & FMODE_READ) {
6452 struct seq_file *m = file->private_data;
6456 parser = &fgd->parser;
6458 read = trace_get_user(parser, ubuf, cnt, ppos);
6460 if (read >= 0 && trace_parser_loaded(parser) &&
6461 !trace_parser_cont(parser)) {
6463 ret = ftrace_graph_set_hash(fgd->new_hash,
6465 trace_parser_clear(parser);
6474 static const struct file_operations ftrace_graph_fops = {
6475 .open = ftrace_graph_open,
6477 .write = ftrace_graph_write,
6478 .llseek = tracing_lseek,
6479 .release = ftrace_graph_release,
6482 static const struct file_operations ftrace_graph_notrace_fops = {
6483 .open = ftrace_graph_notrace_open,
6485 .write = ftrace_graph_write,
6486 .llseek = tracing_lseek,
6487 .release = ftrace_graph_release,
6489 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6491 void ftrace_create_filter_files(struct ftrace_ops *ops,
6492 struct dentry *parent)
6495 trace_create_file("set_ftrace_filter", TRACE_MODE_WRITE, parent,
6496 ops, &ftrace_filter_fops);
6498 trace_create_file("set_ftrace_notrace", TRACE_MODE_WRITE, parent,
6499 ops, &ftrace_notrace_fops);
6503 * The name "destroy_filter_files" is really a misnomer. Although
6504 * in the future, it may actually delete the files, but this is
6505 * really intended to make sure the ops passed in are disabled
6506 * and that when this function returns, the caller is free to
6509 * The "destroy" name is only to match the "create" name that this
6510 * should be paired with.
6512 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
6514 mutex_lock(&ftrace_lock);
6515 if (ops->flags & FTRACE_OPS_FL_ENABLED)
6516 ftrace_shutdown(ops, 0);
6517 ops->flags |= FTRACE_OPS_FL_DELETED;
6518 ftrace_free_filter(ops);
6519 mutex_unlock(&ftrace_lock);
6522 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
6525 trace_create_file("available_filter_functions", TRACE_MODE_READ,
6526 d_tracer, NULL, &ftrace_avail_fops);
6528 trace_create_file("enabled_functions", TRACE_MODE_READ,
6529 d_tracer, NULL, &ftrace_enabled_fops);
6531 ftrace_create_filter_files(&global_ops, d_tracer);
6533 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
6534 trace_create_file("set_graph_function", TRACE_MODE_WRITE, d_tracer,
6536 &ftrace_graph_fops);
6537 trace_create_file("set_graph_notrace", TRACE_MODE_WRITE, d_tracer,
6539 &ftrace_graph_notrace_fops);
6540 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6545 static int ftrace_cmp_ips(const void *a, const void *b)
6547 const unsigned long *ipa = a;
6548 const unsigned long *ipb = b;
6557 #ifdef CONFIG_FTRACE_SORT_STARTUP_TEST
6558 static void test_is_sorted(unsigned long *start, unsigned long count)
6562 for (i = 1; i < count; i++) {
6563 if (WARN(start[i - 1] > start[i],
6564 "[%d] %pS at %lx is not sorted with %pS at %lx\n", i,
6565 (void *)start[i - 1], start[i - 1],
6566 (void *)start[i], start[i]))
6570 pr_info("ftrace section at %px sorted properly\n", start);
6573 static void test_is_sorted(unsigned long *start, unsigned long count)
6578 static int ftrace_process_locs(struct module *mod,
6579 unsigned long *start,
6582 struct ftrace_page *start_pg;
6583 struct ftrace_page *pg;
6584 struct dyn_ftrace *rec;
6585 unsigned long count;
6588 unsigned long flags = 0; /* Shut up gcc */
6591 count = end - start;
6597 * Sorting mcount in vmlinux at build time depend on
6598 * CONFIG_BUILDTIME_MCOUNT_SORT, while mcount loc in
6599 * modules can not be sorted at build time.
6601 if (!IS_ENABLED(CONFIG_BUILDTIME_MCOUNT_SORT) || mod) {
6602 sort(start, count, sizeof(*start),
6603 ftrace_cmp_ips, NULL);
6605 test_is_sorted(start, count);
6608 start_pg = ftrace_allocate_pages(count);
6612 mutex_lock(&ftrace_lock);
6615 * Core and each module needs their own pages, as
6616 * modules will free them when they are removed.
6617 * Force a new page to be allocated for modules.
6620 WARN_ON(ftrace_pages || ftrace_pages_start);
6621 /* First initialization */
6622 ftrace_pages = ftrace_pages_start = start_pg;
6627 if (WARN_ON(ftrace_pages->next)) {
6628 /* Hmm, we have free pages? */
6629 while (ftrace_pages->next)
6630 ftrace_pages = ftrace_pages->next;
6633 ftrace_pages->next = start_pg;
6639 unsigned long end_offset;
6640 addr = ftrace_call_adjust(*p++);
6642 * Some architecture linkers will pad between
6643 * the different mcount_loc sections of different
6644 * object files to satisfy alignments.
6645 * Skip any NULL pointers.
6650 end_offset = (pg->index+1) * sizeof(pg->records[0]);
6651 if (end_offset > PAGE_SIZE << pg->order) {
6652 /* We should have allocated enough */
6653 if (WARN_ON(!pg->next))
6658 rec = &pg->records[pg->index++];
6662 /* We should have used all pages */
6665 /* Assign the last page to ftrace_pages */
6669 * We only need to disable interrupts on start up
6670 * because we are modifying code that an interrupt
6671 * may execute, and the modification is not atomic.
6672 * But for modules, nothing runs the code we modify
6673 * until we are finished with it, and there's no
6674 * reason to cause large interrupt latencies while we do it.
6677 local_irq_save(flags);
6678 ftrace_update_code(mod, start_pg);
6680 local_irq_restore(flags);
6683 mutex_unlock(&ftrace_lock);
6688 struct ftrace_mod_func {
6689 struct list_head list;
6695 struct ftrace_mod_map {
6696 struct rcu_head rcu;
6697 struct list_head list;
6699 unsigned long start_addr;
6700 unsigned long end_addr;
6701 struct list_head funcs;
6702 unsigned int num_funcs;
6705 static int ftrace_get_trampoline_kallsym(unsigned int symnum,
6706 unsigned long *value, char *type,
6707 char *name, char *module_name,
6710 struct ftrace_ops *op;
6712 list_for_each_entry_rcu(op, &ftrace_ops_trampoline_list, list) {
6713 if (!op->trampoline || symnum--)
6715 *value = op->trampoline;
6717 strlcpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
6718 strlcpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
6726 #ifdef CONFIG_MODULES
6728 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
6730 static LIST_HEAD(ftrace_mod_maps);
6732 static int referenced_filters(struct dyn_ftrace *rec)
6734 struct ftrace_ops *ops;
6737 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
6738 if (ops_references_rec(ops, rec)) {
6739 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_DIRECT))
6741 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_IPMODIFY))
6744 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
6745 rec->flags |= FTRACE_FL_REGS;
6746 if (cnt == 1 && ops->trampoline)
6747 rec->flags |= FTRACE_FL_TRAMP;
6749 rec->flags &= ~FTRACE_FL_TRAMP;
6757 clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
6759 struct ftrace_func_entry *entry;
6760 struct dyn_ftrace *rec;
6763 if (ftrace_hash_empty(hash))
6766 for (i = 0; i < pg->index; i++) {
6767 rec = &pg->records[i];
6768 entry = __ftrace_lookup_ip(hash, rec->ip);
6770 * Do not allow this rec to match again.
6771 * Yeah, it may waste some memory, but will be removed
6772 * if/when the hash is modified again.
6779 /* Clear any records from hashes */
6780 static void clear_mod_from_hashes(struct ftrace_page *pg)
6782 struct trace_array *tr;
6784 mutex_lock(&trace_types_lock);
6785 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6786 if (!tr->ops || !tr->ops->func_hash)
6788 mutex_lock(&tr->ops->func_hash->regex_lock);
6789 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
6790 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
6791 mutex_unlock(&tr->ops->func_hash->regex_lock);
6793 mutex_unlock(&trace_types_lock);
6796 static void ftrace_free_mod_map(struct rcu_head *rcu)
6798 struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
6799 struct ftrace_mod_func *mod_func;
6800 struct ftrace_mod_func *n;
6802 /* All the contents of mod_map are now not visible to readers */
6803 list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
6804 kfree(mod_func->name);
6805 list_del(&mod_func->list);
6812 void ftrace_release_mod(struct module *mod)
6814 struct ftrace_mod_map *mod_map;
6815 struct ftrace_mod_map *n;
6816 struct dyn_ftrace *rec;
6817 struct ftrace_page **last_pg;
6818 struct ftrace_page *tmp_page = NULL;
6819 struct ftrace_page *pg;
6821 mutex_lock(&ftrace_lock);
6823 if (ftrace_disabled)
6826 list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
6827 if (mod_map->mod == mod) {
6828 list_del_rcu(&mod_map->list);
6829 call_rcu(&mod_map->rcu, ftrace_free_mod_map);
6835 * Each module has its own ftrace_pages, remove
6836 * them from the list.
6838 last_pg = &ftrace_pages_start;
6839 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
6840 rec = &pg->records[0];
6841 if (within_module_core(rec->ip, mod) ||
6842 within_module_init(rec->ip, mod)) {
6844 * As core pages are first, the first
6845 * page should never be a module page.
6847 if (WARN_ON(pg == ftrace_pages_start))
6850 /* Check if we are deleting the last page */
6851 if (pg == ftrace_pages)
6852 ftrace_pages = next_to_ftrace_page(last_pg);
6854 ftrace_update_tot_cnt -= pg->index;
6855 *last_pg = pg->next;
6857 pg->next = tmp_page;
6860 last_pg = &pg->next;
6863 mutex_unlock(&ftrace_lock);
6865 for (pg = tmp_page; pg; pg = tmp_page) {
6867 /* Needs to be called outside of ftrace_lock */
6868 clear_mod_from_hashes(pg);
6871 free_pages((unsigned long)pg->records, pg->order);
6872 ftrace_number_of_pages -= 1 << pg->order;
6874 tmp_page = pg->next;
6876 ftrace_number_of_groups--;
6880 void ftrace_module_enable(struct module *mod)
6882 struct dyn_ftrace *rec;
6883 struct ftrace_page *pg;
6885 mutex_lock(&ftrace_lock);
6887 if (ftrace_disabled)
6891 * If the tracing is enabled, go ahead and enable the record.
6893 * The reason not to enable the record immediately is the
6894 * inherent check of ftrace_make_nop/ftrace_make_call for
6895 * correct previous instructions. Making first the NOP
6896 * conversion puts the module to the correct state, thus
6897 * passing the ftrace_make_call check.
6899 * We also delay this to after the module code already set the
6900 * text to read-only, as we now need to set it back to read-write
6901 * so that we can modify the text.
6903 if (ftrace_start_up)
6904 ftrace_arch_code_modify_prepare();
6906 do_for_each_ftrace_rec(pg, rec) {
6909 * do_for_each_ftrace_rec() is a double loop.
6910 * module text shares the pg. If a record is
6911 * not part of this module, then skip this pg,
6912 * which the "break" will do.
6914 if (!within_module_core(rec->ip, mod) &&
6915 !within_module_init(rec->ip, mod))
6918 /* Weak functions should still be ignored */
6919 if (!test_for_valid_rec(rec)) {
6920 /* Clear all other flags. Should not be enabled anyway */
6921 rec->flags = FTRACE_FL_DISABLED;
6928 * When adding a module, we need to check if tracers are
6929 * currently enabled and if they are, and can trace this record,
6930 * we need to enable the module functions as well as update the
6931 * reference counts for those function records.
6933 if (ftrace_start_up)
6934 cnt += referenced_filters(rec);
6936 rec->flags &= ~FTRACE_FL_DISABLED;
6939 if (ftrace_start_up && cnt) {
6940 int failed = __ftrace_replace_code(rec, 1);
6942 ftrace_bug(failed, rec);
6947 } while_for_each_ftrace_rec();
6950 if (ftrace_start_up)
6951 ftrace_arch_code_modify_post_process();
6954 mutex_unlock(&ftrace_lock);
6956 process_cached_mods(mod->name);
6959 void ftrace_module_init(struct module *mod)
6963 if (ftrace_disabled || !mod->num_ftrace_callsites)
6966 ret = ftrace_process_locs(mod, mod->ftrace_callsites,
6967 mod->ftrace_callsites + mod->num_ftrace_callsites);
6969 pr_warn("ftrace: failed to allocate entries for module '%s' functions\n",
6973 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6974 struct dyn_ftrace *rec)
6976 struct ftrace_mod_func *mod_func;
6977 unsigned long symsize;
6978 unsigned long offset;
6979 char str[KSYM_SYMBOL_LEN];
6983 ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
6987 mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
6991 mod_func->name = kstrdup(str, GFP_KERNEL);
6992 if (!mod_func->name) {
6997 mod_func->ip = rec->ip - offset;
6998 mod_func->size = symsize;
7000 mod_map->num_funcs++;
7002 list_add_rcu(&mod_func->list, &mod_map->funcs);
7005 static struct ftrace_mod_map *
7006 allocate_ftrace_mod_map(struct module *mod,
7007 unsigned long start, unsigned long end)
7009 struct ftrace_mod_map *mod_map;
7011 mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
7016 mod_map->start_addr = start;
7017 mod_map->end_addr = end;
7018 mod_map->num_funcs = 0;
7020 INIT_LIST_HEAD_RCU(&mod_map->funcs);
7022 list_add_rcu(&mod_map->list, &ftrace_mod_maps);
7028 ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
7029 unsigned long addr, unsigned long *size,
7030 unsigned long *off, char *sym)
7032 struct ftrace_mod_func *found_func = NULL;
7033 struct ftrace_mod_func *mod_func;
7035 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
7036 if (addr >= mod_func->ip &&
7037 addr < mod_func->ip + mod_func->size) {
7038 found_func = mod_func;
7045 *size = found_func->size;
7047 *off = addr - found_func->ip;
7049 strlcpy(sym, found_func->name, KSYM_NAME_LEN);
7051 return found_func->name;
7058 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
7059 unsigned long *off, char **modname, char *sym)
7061 struct ftrace_mod_map *mod_map;
7062 const char *ret = NULL;
7064 /* mod_map is freed via call_rcu() */
7066 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
7067 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
7070 *modname = mod_map->mod->name;
7079 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7080 char *type, char *name,
7081 char *module_name, int *exported)
7083 struct ftrace_mod_map *mod_map;
7084 struct ftrace_mod_func *mod_func;
7088 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
7090 if (symnum >= mod_map->num_funcs) {
7091 symnum -= mod_map->num_funcs;
7095 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
7101 *value = mod_func->ip;
7103 strlcpy(name, mod_func->name, KSYM_NAME_LEN);
7104 strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
7112 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7113 module_name, exported);
7119 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
7120 struct dyn_ftrace *rec) { }
7121 static inline struct ftrace_mod_map *
7122 allocate_ftrace_mod_map(struct module *mod,
7123 unsigned long start, unsigned long end)
7127 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7128 char *type, char *name, char *module_name,
7134 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7135 module_name, exported);
7139 #endif /* CONFIG_MODULES */
7141 struct ftrace_init_func {
7142 struct list_head list;
7146 /* Clear any init ips from hashes */
7148 clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
7150 struct ftrace_func_entry *entry;
7152 entry = ftrace_lookup_ip(hash, func->ip);
7154 * Do not allow this rec to match again.
7155 * Yeah, it may waste some memory, but will be removed
7156 * if/when the hash is modified again.
7163 clear_func_from_hashes(struct ftrace_init_func *func)
7165 struct trace_array *tr;
7167 mutex_lock(&trace_types_lock);
7168 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
7169 if (!tr->ops || !tr->ops->func_hash)
7171 mutex_lock(&tr->ops->func_hash->regex_lock);
7172 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
7173 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
7174 mutex_unlock(&tr->ops->func_hash->regex_lock);
7176 mutex_unlock(&trace_types_lock);
7179 static void add_to_clear_hash_list(struct list_head *clear_list,
7180 struct dyn_ftrace *rec)
7182 struct ftrace_init_func *func;
7184 func = kmalloc(sizeof(*func), GFP_KERNEL);
7186 MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
7191 list_add(&func->list, clear_list);
7194 void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
7196 unsigned long start = (unsigned long)(start_ptr);
7197 unsigned long end = (unsigned long)(end_ptr);
7198 struct ftrace_page **last_pg = &ftrace_pages_start;
7199 struct ftrace_page *pg;
7200 struct dyn_ftrace *rec;
7201 struct dyn_ftrace key;
7202 struct ftrace_mod_map *mod_map = NULL;
7203 struct ftrace_init_func *func, *func_next;
7204 struct list_head clear_hash;
7206 INIT_LIST_HEAD(&clear_hash);
7209 key.flags = end; /* overload flags, as it is unsigned long */
7211 mutex_lock(&ftrace_lock);
7214 * If we are freeing module init memory, then check if
7215 * any tracer is active. If so, we need to save a mapping of
7216 * the module functions being freed with the address.
7218 if (mod && ftrace_ops_list != &ftrace_list_end)
7219 mod_map = allocate_ftrace_mod_map(mod, start, end);
7221 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
7222 if (end < pg->records[0].ip ||
7223 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
7226 rec = bsearch(&key, pg->records, pg->index,
7227 sizeof(struct dyn_ftrace),
7232 /* rec will be cleared from hashes after ftrace_lock unlock */
7233 add_to_clear_hash_list(&clear_hash, rec);
7236 save_ftrace_mod_rec(mod_map, rec);
7239 ftrace_update_tot_cnt--;
7241 *last_pg = pg->next;
7243 free_pages((unsigned long)pg->records, pg->order);
7244 ftrace_number_of_pages -= 1 << pg->order;
7246 ftrace_number_of_groups--;
7248 pg = container_of(last_pg, struct ftrace_page, next);
7253 memmove(rec, rec + 1,
7254 (pg->index - (rec - pg->records)) * sizeof(*rec));
7255 /* More than one function may be in this block */
7258 mutex_unlock(&ftrace_lock);
7260 list_for_each_entry_safe(func, func_next, &clear_hash, list) {
7261 clear_func_from_hashes(func);
7266 void __init ftrace_free_init_mem(void)
7268 void *start = (void *)(&__init_begin);
7269 void *end = (void *)(&__init_end);
7271 ftrace_boot_snapshot();
7273 ftrace_free_mem(NULL, start, end);
7276 int __init __weak ftrace_dyn_arch_init(void)
7281 void __init ftrace_init(void)
7283 extern unsigned long __start_mcount_loc[];
7284 extern unsigned long __stop_mcount_loc[];
7285 unsigned long count, flags;
7288 local_irq_save(flags);
7289 ret = ftrace_dyn_arch_init();
7290 local_irq_restore(flags);
7294 count = __stop_mcount_loc - __start_mcount_loc;
7296 pr_info("ftrace: No functions to be traced?\n");
7300 pr_info("ftrace: allocating %ld entries in %ld pages\n",
7301 count, count / ENTRIES_PER_PAGE + 1);
7303 ret = ftrace_process_locs(NULL,
7307 pr_warn("ftrace: failed to allocate entries for functions\n");
7311 pr_info("ftrace: allocated %ld pages with %ld groups\n",
7312 ftrace_number_of_pages, ftrace_number_of_groups);
7314 last_ftrace_enabled = ftrace_enabled = 1;
7316 set_ftrace_early_filters();
7320 ftrace_disabled = 1;
7323 /* Do nothing if arch does not support this */
7324 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
7328 static void ftrace_update_trampoline(struct ftrace_ops *ops)
7330 unsigned long trampoline = ops->trampoline;
7332 arch_ftrace_update_trampoline(ops);
7333 if (ops->trampoline && ops->trampoline != trampoline &&
7334 (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) {
7335 /* Add to kallsyms before the perf events */
7336 ftrace_add_trampoline_to_kallsyms(ops);
7337 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
7338 ops->trampoline, ops->trampoline_size, false,
7339 FTRACE_TRAMPOLINE_SYM);
7341 * Record the perf text poke event after the ksymbol register
7344 perf_event_text_poke((void *)ops->trampoline, NULL, 0,
7345 (void *)ops->trampoline,
7346 ops->trampoline_size);
7350 void ftrace_init_trace_array(struct trace_array *tr)
7352 INIT_LIST_HEAD(&tr->func_probes);
7353 INIT_LIST_HEAD(&tr->mod_trace);
7354 INIT_LIST_HEAD(&tr->mod_notrace);
7358 struct ftrace_ops global_ops = {
7359 .func = ftrace_stub,
7360 .flags = FTRACE_OPS_FL_INITIALIZED |
7364 static int __init ftrace_nodyn_init(void)
7369 core_initcall(ftrace_nodyn_init);
7371 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
7372 static inline void ftrace_startup_all(int command) { }
7374 static void ftrace_update_trampoline(struct ftrace_ops *ops)
7378 #endif /* CONFIG_DYNAMIC_FTRACE */
7380 __init void ftrace_init_global_array_ops(struct trace_array *tr)
7382 tr->ops = &global_ops;
7383 tr->ops->private = tr;
7384 ftrace_init_trace_array(tr);
7387 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
7389 /* If we filter on pids, update to use the pid function */
7390 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
7391 if (WARN_ON(tr->ops->func != ftrace_stub))
7392 printk("ftrace ops had %pS for function\n",
7395 tr->ops->func = func;
7396 tr->ops->private = tr;
7399 void ftrace_reset_array_ops(struct trace_array *tr)
7401 tr->ops->func = ftrace_stub;
7404 static nokprobe_inline void
7405 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7406 struct ftrace_ops *ignored, struct ftrace_regs *fregs)
7408 struct pt_regs *regs = ftrace_get_regs(fregs);
7409 struct ftrace_ops *op;
7413 * The ftrace_test_and_set_recursion() will disable preemption,
7414 * which is required since some of the ops may be dynamically
7415 * allocated, they must be freed after a synchronize_rcu().
7417 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7421 do_for_each_ftrace_op(op, ftrace_ops_list) {
7422 /* Stub functions don't need to be called nor tested */
7423 if (op->flags & FTRACE_OPS_FL_STUB)
7426 * Check the following for each ops before calling their func:
7427 * if RCU flag is set, then rcu_is_watching() must be true
7428 * if PER_CPU is set, then ftrace_function_local_disable()
7430 * Otherwise test if the ip matches the ops filter
7432 * If any of the above fails then the op->func() is not executed.
7434 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
7435 ftrace_ops_test(op, ip, regs)) {
7436 if (FTRACE_WARN_ON(!op->func)) {
7437 pr_warn("op=%p %pS\n", op, op);
7440 op->func(ip, parent_ip, op, fregs);
7442 } while_for_each_ftrace_op(op);
7444 trace_clear_recursion(bit);
7448 * Some archs only support passing ip and parent_ip. Even though
7449 * the list function ignores the op parameter, we do not want any
7450 * C side effects, where a function is called without the caller
7451 * sending a third parameter.
7452 * Archs are to support both the regs and ftrace_ops at the same time.
7453 * If they support ftrace_ops, it is assumed they support regs.
7454 * If call backs want to use regs, they must either check for regs
7455 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
7456 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
7457 * An architecture can pass partial regs with ftrace_ops and still
7458 * set the ARCH_SUPPORTS_FTRACE_OPS.
7460 * In vmlinux.lds.h, ftrace_ops_list_func() is defined to be
7461 * arch_ftrace_ops_list_func.
7463 #if ARCH_SUPPORTS_FTRACE_OPS
7464 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7465 struct ftrace_ops *op, struct ftrace_regs *fregs)
7467 __ftrace_ops_list_func(ip, parent_ip, NULL, fregs);
7470 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
7472 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
7475 NOKPROBE_SYMBOL(arch_ftrace_ops_list_func);
7478 * If there's only one function registered but it does not support
7479 * recursion, needs RCU protection and/or requires per cpu handling, then
7480 * this function will be called by the mcount trampoline.
7482 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
7483 struct ftrace_ops *op, struct ftrace_regs *fregs)
7487 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7491 if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
7492 op->func(ip, parent_ip, op, fregs);
7494 trace_clear_recursion(bit);
7496 NOKPROBE_SYMBOL(ftrace_ops_assist_func);
7499 * ftrace_ops_get_func - get the function a trampoline should call
7500 * @ops: the ops to get the function for
7502 * Normally the mcount trampoline will call the ops->func, but there
7503 * are times that it should not. For example, if the ops does not
7504 * have its own recursion protection, then it should call the
7505 * ftrace_ops_assist_func() instead.
7507 * Returns the function that the trampoline should call for @ops.
7509 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
7512 * If the function does not handle recursion or needs to be RCU safe,
7513 * then we need to call the assist handler.
7515 if (ops->flags & (FTRACE_OPS_FL_RECURSION |
7517 return ftrace_ops_assist_func;
7523 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
7524 struct task_struct *prev,
7525 struct task_struct *next,
7526 unsigned int prev_state)
7528 struct trace_array *tr = data;
7529 struct trace_pid_list *pid_list;
7530 struct trace_pid_list *no_pid_list;
7532 pid_list = rcu_dereference_sched(tr->function_pids);
7533 no_pid_list = rcu_dereference_sched(tr->function_no_pids);
7535 if (trace_ignore_this_task(pid_list, no_pid_list, next))
7536 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7539 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7544 ftrace_pid_follow_sched_process_fork(void *data,
7545 struct task_struct *self,
7546 struct task_struct *task)
7548 struct trace_pid_list *pid_list;
7549 struct trace_array *tr = data;
7551 pid_list = rcu_dereference_sched(tr->function_pids);
7552 trace_filter_add_remove_task(pid_list, self, task);
7554 pid_list = rcu_dereference_sched(tr->function_no_pids);
7555 trace_filter_add_remove_task(pid_list, self, task);
7559 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
7561 struct trace_pid_list *pid_list;
7562 struct trace_array *tr = data;
7564 pid_list = rcu_dereference_sched(tr->function_pids);
7565 trace_filter_add_remove_task(pid_list, NULL, task);
7567 pid_list = rcu_dereference_sched(tr->function_no_pids);
7568 trace_filter_add_remove_task(pid_list, NULL, task);
7571 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
7574 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7576 register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7579 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7581 unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7586 static void clear_ftrace_pids(struct trace_array *tr, int type)
7588 struct trace_pid_list *pid_list;
7589 struct trace_pid_list *no_pid_list;
7592 pid_list = rcu_dereference_protected(tr->function_pids,
7593 lockdep_is_held(&ftrace_lock));
7594 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7595 lockdep_is_held(&ftrace_lock));
7597 /* Make sure there's something to do */
7598 if (!pid_type_enabled(type, pid_list, no_pid_list))
7601 /* See if the pids still need to be checked after this */
7602 if (!still_need_pid_events(type, pid_list, no_pid_list)) {
7603 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7604 for_each_possible_cpu(cpu)
7605 per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
7608 if (type & TRACE_PIDS)
7609 rcu_assign_pointer(tr->function_pids, NULL);
7611 if (type & TRACE_NO_PIDS)
7612 rcu_assign_pointer(tr->function_no_pids, NULL);
7614 /* Wait till all users are no longer using pid filtering */
7617 if ((type & TRACE_PIDS) && pid_list)
7618 trace_pid_list_free(pid_list);
7620 if ((type & TRACE_NO_PIDS) && no_pid_list)
7621 trace_pid_list_free(no_pid_list);
7624 void ftrace_clear_pids(struct trace_array *tr)
7626 mutex_lock(&ftrace_lock);
7628 clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
7630 mutex_unlock(&ftrace_lock);
7633 static void ftrace_pid_reset(struct trace_array *tr, int type)
7635 mutex_lock(&ftrace_lock);
7636 clear_ftrace_pids(tr, type);
7638 ftrace_update_pid_func();
7639 ftrace_startup_all(0);
7641 mutex_unlock(&ftrace_lock);
7644 /* Greater than any max PID */
7645 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
7647 static void *fpid_start(struct seq_file *m, loff_t *pos)
7650 struct trace_pid_list *pid_list;
7651 struct trace_array *tr = m->private;
7653 mutex_lock(&ftrace_lock);
7654 rcu_read_lock_sched();
7656 pid_list = rcu_dereference_sched(tr->function_pids);
7659 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7661 return trace_pid_start(pid_list, pos);
7664 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
7666 struct trace_array *tr = m->private;
7667 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
7669 if (v == FTRACE_NO_PIDS) {
7673 return trace_pid_next(pid_list, v, pos);
7676 static void fpid_stop(struct seq_file *m, void *p)
7679 rcu_read_unlock_sched();
7680 mutex_unlock(&ftrace_lock);
7683 static int fpid_show(struct seq_file *m, void *v)
7685 if (v == FTRACE_NO_PIDS) {
7686 seq_puts(m, "no pid\n");
7690 return trace_pid_show(m, v);
7693 static const struct seq_operations ftrace_pid_sops = {
7694 .start = fpid_start,
7700 static void *fnpid_start(struct seq_file *m, loff_t *pos)
7703 struct trace_pid_list *pid_list;
7704 struct trace_array *tr = m->private;
7706 mutex_lock(&ftrace_lock);
7707 rcu_read_lock_sched();
7709 pid_list = rcu_dereference_sched(tr->function_no_pids);
7712 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7714 return trace_pid_start(pid_list, pos);
7717 static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
7719 struct trace_array *tr = m->private;
7720 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
7722 if (v == FTRACE_NO_PIDS) {
7726 return trace_pid_next(pid_list, v, pos);
7729 static const struct seq_operations ftrace_no_pid_sops = {
7730 .start = fnpid_start,
7736 static int pid_open(struct inode *inode, struct file *file, int type)
7738 const struct seq_operations *seq_ops;
7739 struct trace_array *tr = inode->i_private;
7743 ret = tracing_check_open_get_tr(tr);
7747 if ((file->f_mode & FMODE_WRITE) &&
7748 (file->f_flags & O_TRUNC))
7749 ftrace_pid_reset(tr, type);
7753 seq_ops = &ftrace_pid_sops;
7756 seq_ops = &ftrace_no_pid_sops;
7759 trace_array_put(tr);
7764 ret = seq_open(file, seq_ops);
7766 trace_array_put(tr);
7768 m = file->private_data;
7769 /* copy tr over to seq ops */
7777 ftrace_pid_open(struct inode *inode, struct file *file)
7779 return pid_open(inode, file, TRACE_PIDS);
7783 ftrace_no_pid_open(struct inode *inode, struct file *file)
7785 return pid_open(inode, file, TRACE_NO_PIDS);
7788 static void ignore_task_cpu(void *data)
7790 struct trace_array *tr = data;
7791 struct trace_pid_list *pid_list;
7792 struct trace_pid_list *no_pid_list;
7795 * This function is called by on_each_cpu() while the
7796 * event_mutex is held.
7798 pid_list = rcu_dereference_protected(tr->function_pids,
7799 mutex_is_locked(&ftrace_lock));
7800 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7801 mutex_is_locked(&ftrace_lock));
7803 if (trace_ignore_this_task(pid_list, no_pid_list, current))
7804 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7807 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7812 pid_write(struct file *filp, const char __user *ubuf,
7813 size_t cnt, loff_t *ppos, int type)
7815 struct seq_file *m = filp->private_data;
7816 struct trace_array *tr = m->private;
7817 struct trace_pid_list *filtered_pids;
7818 struct trace_pid_list *other_pids;
7819 struct trace_pid_list *pid_list;
7825 mutex_lock(&ftrace_lock);
7829 filtered_pids = rcu_dereference_protected(tr->function_pids,
7830 lockdep_is_held(&ftrace_lock));
7831 other_pids = rcu_dereference_protected(tr->function_no_pids,
7832 lockdep_is_held(&ftrace_lock));
7835 filtered_pids = rcu_dereference_protected(tr->function_no_pids,
7836 lockdep_is_held(&ftrace_lock));
7837 other_pids = rcu_dereference_protected(tr->function_pids,
7838 lockdep_is_held(&ftrace_lock));
7846 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
7852 rcu_assign_pointer(tr->function_pids, pid_list);
7855 rcu_assign_pointer(tr->function_no_pids, pid_list);
7860 if (filtered_pids) {
7862 trace_pid_list_free(filtered_pids);
7863 } else if (pid_list && !other_pids) {
7864 /* Register a probe to set whether to ignore the tracing of a task */
7865 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7869 * Ignoring of pids is done at task switch. But we have to
7870 * check for those tasks that are currently running.
7871 * Always do this in case a pid was appended or removed.
7873 on_each_cpu(ignore_task_cpu, tr, 1);
7875 ftrace_update_pid_func();
7876 ftrace_startup_all(0);
7878 mutex_unlock(&ftrace_lock);
7887 ftrace_pid_write(struct file *filp, const char __user *ubuf,
7888 size_t cnt, loff_t *ppos)
7890 return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
7894 ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
7895 size_t cnt, loff_t *ppos)
7897 return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
7901 ftrace_pid_release(struct inode *inode, struct file *file)
7903 struct trace_array *tr = inode->i_private;
7905 trace_array_put(tr);
7907 return seq_release(inode, file);
7910 static const struct file_operations ftrace_pid_fops = {
7911 .open = ftrace_pid_open,
7912 .write = ftrace_pid_write,
7914 .llseek = tracing_lseek,
7915 .release = ftrace_pid_release,
7918 static const struct file_operations ftrace_no_pid_fops = {
7919 .open = ftrace_no_pid_open,
7920 .write = ftrace_no_pid_write,
7922 .llseek = tracing_lseek,
7923 .release = ftrace_pid_release,
7926 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
7928 trace_create_file("set_ftrace_pid", TRACE_MODE_WRITE, d_tracer,
7929 tr, &ftrace_pid_fops);
7930 trace_create_file("set_ftrace_notrace_pid", TRACE_MODE_WRITE,
7931 d_tracer, tr, &ftrace_no_pid_fops);
7934 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
7935 struct dentry *d_tracer)
7937 /* Only the top level directory has the dyn_tracefs and profile */
7938 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
7940 ftrace_init_dyn_tracefs(d_tracer);
7941 ftrace_profile_tracefs(d_tracer);
7945 * ftrace_kill - kill ftrace
7947 * This function should be used by panic code. It stops ftrace
7948 * but in a not so nice way. If you need to simply kill ftrace
7949 * from a non-atomic section, use ftrace_kill.
7951 void ftrace_kill(void)
7953 ftrace_disabled = 1;
7955 ftrace_trace_function = ftrace_stub;
7959 * ftrace_is_dead - Test if ftrace is dead or not.
7961 * Returns 1 if ftrace is "dead", zero otherwise.
7963 int ftrace_is_dead(void)
7965 return ftrace_disabled;
7969 * register_ftrace_function - register a function for profiling
7970 * @ops: ops structure that holds the function for profiling.
7972 * Register a function to be called by all functions in the
7975 * Note: @ops->func and all the functions it calls must be labeled
7976 * with "notrace", otherwise it will go into a
7979 int register_ftrace_function(struct ftrace_ops *ops)
7983 ftrace_ops_init(ops);
7985 mutex_lock(&ftrace_lock);
7987 ret = ftrace_startup(ops, 0);
7989 mutex_unlock(&ftrace_lock);
7993 EXPORT_SYMBOL_GPL(register_ftrace_function);
7996 * unregister_ftrace_function - unregister a function for profiling.
7997 * @ops: ops structure that holds the function to unregister
7999 * Unregister a function that was added to be called by ftrace profiling.
8001 int unregister_ftrace_function(struct ftrace_ops *ops)
8005 mutex_lock(&ftrace_lock);
8006 ret = ftrace_shutdown(ops, 0);
8007 mutex_unlock(&ftrace_lock);
8011 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
8013 static int symbols_cmp(const void *a, const void *b)
8015 const char **str_a = (const char **) a;
8016 const char **str_b = (const char **) b;
8018 return strcmp(*str_a, *str_b);
8021 struct kallsyms_data {
8022 unsigned long *addrs;
8028 static int kallsyms_callback(void *data, const char *name,
8029 struct module *mod, unsigned long addr)
8031 struct kallsyms_data *args = data;
8035 sym = bsearch(&name, args->syms, args->cnt, sizeof(*args->syms), symbols_cmp);
8039 idx = sym - args->syms;
8040 if (args->addrs[idx])
8043 addr = ftrace_location(addr);
8047 args->addrs[idx] = addr;
8049 return args->found == args->cnt ? 1 : 0;
8053 * ftrace_lookup_symbols - Lookup addresses for array of symbols
8055 * @sorted_syms: array of symbols pointers symbols to resolve,
8056 * must be alphabetically sorted
8057 * @cnt: number of symbols/addresses in @syms/@addrs arrays
8058 * @addrs: array for storing resulting addresses
8060 * This function looks up addresses for array of symbols provided in
8061 * @syms array (must be alphabetically sorted) and stores them in
8062 * @addrs array, which needs to be big enough to store at least @cnt
8065 * This function returns 0 if all provided symbols are found,
8068 int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
8070 struct kallsyms_data args;
8073 memset(addrs, 0, sizeof(*addrs) * cnt);
8075 args.syms = sorted_syms;
8078 err = kallsyms_on_each_symbol(kallsyms_callback, &args);
8081 return args.found == args.cnt ? 0 : -ESRCH;
8084 #ifdef CONFIG_SYSCTL
8086 #ifdef CONFIG_DYNAMIC_FTRACE
8087 static void ftrace_startup_sysctl(void)
8091 if (unlikely(ftrace_disabled))
8094 /* Force update next time */
8095 saved_ftrace_func = NULL;
8096 /* ftrace_start_up is true if we want ftrace running */
8097 if (ftrace_start_up) {
8098 command = FTRACE_UPDATE_CALLS;
8099 if (ftrace_graph_active)
8100 command |= FTRACE_START_FUNC_RET;
8101 ftrace_startup_enable(command);
8105 static void ftrace_shutdown_sysctl(void)
8109 if (unlikely(ftrace_disabled))
8112 /* ftrace_start_up is true if ftrace is running */
8113 if (ftrace_start_up) {
8114 command = FTRACE_DISABLE_CALLS;
8115 if (ftrace_graph_active)
8116 command |= FTRACE_STOP_FUNC_RET;
8117 ftrace_run_update_code(command);
8121 # define ftrace_startup_sysctl() do { } while (0)
8122 # define ftrace_shutdown_sysctl() do { } while (0)
8123 #endif /* CONFIG_DYNAMIC_FTRACE */
8125 static bool is_permanent_ops_registered(void)
8127 struct ftrace_ops *op;
8129 do_for_each_ftrace_op(op, ftrace_ops_list) {
8130 if (op->flags & FTRACE_OPS_FL_PERMANENT)
8132 } while_for_each_ftrace_op(op);
8138 ftrace_enable_sysctl(struct ctl_table *table, int write,
8139 void *buffer, size_t *lenp, loff_t *ppos)
8143 mutex_lock(&ftrace_lock);
8145 if (unlikely(ftrace_disabled))
8148 ret = proc_dointvec(table, write, buffer, lenp, ppos);
8150 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
8153 if (ftrace_enabled) {
8155 /* we are starting ftrace again */
8156 if (rcu_dereference_protected(ftrace_ops_list,
8157 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
8158 update_ftrace_function();
8160 ftrace_startup_sysctl();
8163 if (is_permanent_ops_registered()) {
8164 ftrace_enabled = true;
8169 /* stopping ftrace calls (just send to ftrace_stub) */
8170 ftrace_trace_function = ftrace_stub;
8172 ftrace_shutdown_sysctl();
8175 last_ftrace_enabled = !!ftrace_enabled;
8177 mutex_unlock(&ftrace_lock);
8181 static struct ctl_table ftrace_sysctls[] = {
8183 .procname = "ftrace_enabled",
8184 .data = &ftrace_enabled,
8185 .maxlen = sizeof(int),
8187 .proc_handler = ftrace_enable_sysctl,
8192 static int __init ftrace_sysctl_init(void)
8194 register_sysctl_init("kernel", ftrace_sysctls);
8197 late_initcall(ftrace_sysctl_init);