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_WARN_ON(cond) \
56 #define FTRACE_WARN_ON_ONCE(cond) \
59 if (WARN_ON_ONCE(___r)) \
64 /* hash bits for specific function selection */
65 #define FTRACE_HASH_DEFAULT_BITS 10
66 #define FTRACE_HASH_MAX_BITS 12
68 #ifdef CONFIG_DYNAMIC_FTRACE
69 #define INIT_OPS_HASH(opsname) \
70 .func_hash = &opsname.local_hash, \
71 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
73 #define INIT_OPS_HASH(opsname)
77 FTRACE_MODIFY_ENABLE_FL = (1 << 0),
78 FTRACE_MODIFY_MAY_SLEEP_FL = (1 << 1),
81 struct ftrace_ops ftrace_list_end __read_mostly = {
83 .flags = FTRACE_OPS_FL_STUB,
84 INIT_OPS_HASH(ftrace_list_end)
87 /* ftrace_enabled is a method to turn ftrace on or off */
88 int ftrace_enabled __read_mostly;
89 static int last_ftrace_enabled;
91 /* Current function tracing op */
92 struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
93 /* What to set function_trace_op to */
94 static struct ftrace_ops *set_function_trace_op;
96 static bool ftrace_pids_enabled(struct ftrace_ops *ops)
98 struct trace_array *tr;
100 if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
105 return tr->function_pids != NULL || tr->function_no_pids != NULL;
108 static void ftrace_update_trampoline(struct ftrace_ops *ops);
111 * ftrace_disabled is set when an anomaly is discovered.
112 * ftrace_disabled is much stronger than ftrace_enabled.
114 static int ftrace_disabled __read_mostly;
116 DEFINE_MUTEX(ftrace_lock);
118 struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
119 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
120 struct ftrace_ops global_ops;
122 #if ARCH_SUPPORTS_FTRACE_OPS
123 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
124 struct ftrace_ops *op, struct ftrace_regs *fregs);
126 /* See comment below, where ftrace_ops_list_func is defined */
127 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
128 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
131 static inline void ftrace_ops_init(struct ftrace_ops *ops)
133 #ifdef CONFIG_DYNAMIC_FTRACE
134 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
135 mutex_init(&ops->local_hash.regex_lock);
136 ops->func_hash = &ops->local_hash;
137 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
142 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
143 struct ftrace_ops *op, struct ftrace_regs *fregs)
145 struct trace_array *tr = op->private;
149 pid = this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid);
150 if (pid == FTRACE_PID_IGNORE)
152 if (pid != FTRACE_PID_TRACE &&
157 op->saved_func(ip, parent_ip, op, fregs);
160 static void ftrace_sync_ipi(void *data)
162 /* Probably not needed, but do it anyway */
166 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
169 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
170 * then it needs to call the list anyway.
172 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
173 FTRACE_FORCE_LIST_FUNC)
174 return ftrace_ops_list_func;
176 return ftrace_ops_get_func(ops);
179 static void update_ftrace_function(void)
184 * Prepare the ftrace_ops that the arch callback will use.
185 * If there's only one ftrace_ops registered, the ftrace_ops_list
186 * will point to the ops we want.
188 set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
189 lockdep_is_held(&ftrace_lock));
191 /* If there's no ftrace_ops registered, just call the stub function */
192 if (set_function_trace_op == &ftrace_list_end) {
196 * If we are at the end of the list and this ops is
197 * recursion safe and not dynamic and the arch supports passing ops,
198 * then have the mcount trampoline call the function directly.
200 } else if (rcu_dereference_protected(ftrace_ops_list->next,
201 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
202 func = ftrace_ops_get_list_func(ftrace_ops_list);
205 /* Just use the default ftrace_ops */
206 set_function_trace_op = &ftrace_list_end;
207 func = ftrace_ops_list_func;
210 update_function_graph_func();
212 /* If there's no change, then do nothing more here */
213 if (ftrace_trace_function == func)
217 * If we are using the list function, it doesn't care
218 * about the function_trace_ops.
220 if (func == ftrace_ops_list_func) {
221 ftrace_trace_function = func;
223 * Don't even bother setting function_trace_ops,
224 * it would be racy to do so anyway.
229 #ifndef CONFIG_DYNAMIC_FTRACE
231 * For static tracing, we need to be a bit more careful.
232 * The function change takes affect immediately. Thus,
233 * we need to coordinate the setting of the function_trace_ops
234 * with the setting of the ftrace_trace_function.
236 * Set the function to the list ops, which will call the
237 * function we want, albeit indirectly, but it handles the
238 * ftrace_ops and doesn't depend on function_trace_op.
240 ftrace_trace_function = ftrace_ops_list_func;
242 * Make sure all CPUs see this. Yes this is slow, but static
243 * tracing is slow and nasty to have enabled.
245 synchronize_rcu_tasks_rude();
246 /* Now all cpus are using the list ops. */
247 function_trace_op = set_function_trace_op;
248 /* Make sure the function_trace_op is visible on all CPUs */
250 /* Nasty way to force a rmb on all cpus */
251 smp_call_function(ftrace_sync_ipi, NULL, 1);
252 /* OK, we are all set to update the ftrace_trace_function now! */
253 #endif /* !CONFIG_DYNAMIC_FTRACE */
255 ftrace_trace_function = func;
258 static void add_ftrace_ops(struct ftrace_ops __rcu **list,
259 struct ftrace_ops *ops)
261 rcu_assign_pointer(ops->next, *list);
264 * We are entering ops into the list but another
265 * CPU might be walking that list. We need to make sure
266 * the ops->next pointer is valid before another CPU sees
267 * the ops pointer included into the list.
269 rcu_assign_pointer(*list, ops);
272 static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
273 struct ftrace_ops *ops)
275 struct ftrace_ops **p;
278 * If we are removing the last function, then simply point
279 * to the ftrace_stub.
281 if (rcu_dereference_protected(*list,
282 lockdep_is_held(&ftrace_lock)) == ops &&
283 rcu_dereference_protected(ops->next,
284 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
285 *list = &ftrace_list_end;
289 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
300 static void ftrace_update_trampoline(struct ftrace_ops *ops);
302 int __register_ftrace_function(struct ftrace_ops *ops)
304 if (ops->flags & FTRACE_OPS_FL_DELETED)
307 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
310 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
312 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
313 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
314 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
316 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
317 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
320 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
321 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
323 if (!ftrace_enabled && (ops->flags & FTRACE_OPS_FL_PERMANENT))
326 if (!core_kernel_data((unsigned long)ops))
327 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
329 add_ftrace_ops(&ftrace_ops_list, ops);
331 /* Always save the function, and reset at unregistering */
332 ops->saved_func = ops->func;
334 if (ftrace_pids_enabled(ops))
335 ops->func = ftrace_pid_func;
337 ftrace_update_trampoline(ops);
340 update_ftrace_function();
345 int __unregister_ftrace_function(struct ftrace_ops *ops)
349 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
352 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
358 update_ftrace_function();
360 ops->func = ops->saved_func;
365 static void ftrace_update_pid_func(void)
367 struct ftrace_ops *op;
369 /* Only do something if we are tracing something */
370 if (ftrace_trace_function == ftrace_stub)
373 do_for_each_ftrace_op(op, ftrace_ops_list) {
374 if (op->flags & FTRACE_OPS_FL_PID) {
375 op->func = ftrace_pids_enabled(op) ?
376 ftrace_pid_func : op->saved_func;
377 ftrace_update_trampoline(op);
379 } while_for_each_ftrace_op(op);
381 update_ftrace_function();
384 #ifdef CONFIG_FUNCTION_PROFILER
385 struct ftrace_profile {
386 struct hlist_node node;
388 unsigned long counter;
389 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
390 unsigned long long time;
391 unsigned long long time_squared;
395 struct ftrace_profile_page {
396 struct ftrace_profile_page *next;
398 struct ftrace_profile records[];
401 struct ftrace_profile_stat {
403 struct hlist_head *hash;
404 struct ftrace_profile_page *pages;
405 struct ftrace_profile_page *start;
406 struct tracer_stat stat;
409 #define PROFILE_RECORDS_SIZE \
410 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
412 #define PROFILES_PER_PAGE \
413 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
415 static int ftrace_profile_enabled __read_mostly;
417 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
418 static DEFINE_MUTEX(ftrace_profile_lock);
420 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
422 #define FTRACE_PROFILE_HASH_BITS 10
423 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
426 function_stat_next(void *v, int idx)
428 struct ftrace_profile *rec = v;
429 struct ftrace_profile_page *pg;
431 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
437 if ((void *)rec >= (void *)&pg->records[pg->index]) {
441 rec = &pg->records[0];
449 static void *function_stat_start(struct tracer_stat *trace)
451 struct ftrace_profile_stat *stat =
452 container_of(trace, struct ftrace_profile_stat, stat);
454 if (!stat || !stat->start)
457 return function_stat_next(&stat->start->records[0], 0);
460 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
461 /* function graph compares on total time */
462 static int function_stat_cmp(const void *p1, const void *p2)
464 const struct ftrace_profile *a = p1;
465 const struct ftrace_profile *b = p2;
467 if (a->time < b->time)
469 if (a->time > b->time)
475 /* not function graph compares against hits */
476 static int function_stat_cmp(const void *p1, const void *p2)
478 const struct ftrace_profile *a = p1;
479 const struct ftrace_profile *b = p2;
481 if (a->counter < b->counter)
483 if (a->counter > b->counter)
490 static int function_stat_headers(struct seq_file *m)
492 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
493 seq_puts(m, " Function "
496 "--- ---- --- ---\n");
498 seq_puts(m, " Function Hit\n"
504 static int function_stat_show(struct seq_file *m, void *v)
506 struct ftrace_profile *rec = v;
507 char str[KSYM_SYMBOL_LEN];
509 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
510 static struct trace_seq s;
511 unsigned long long avg;
512 unsigned long long stddev;
514 mutex_lock(&ftrace_profile_lock);
516 /* we raced with function_profile_reset() */
517 if (unlikely(rec->counter == 0)) {
522 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
523 avg = div64_ul(rec->time, rec->counter);
524 if (tracing_thresh && (avg < tracing_thresh))
528 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
529 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
531 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
534 /* Sample standard deviation (s^2) */
535 if (rec->counter <= 1)
539 * Apply Welford's method:
540 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
542 stddev = rec->counter * rec->time_squared -
543 rec->time * rec->time;
546 * Divide only 1000 for ns^2 -> us^2 conversion.
547 * trace_print_graph_duration will divide 1000 again.
549 stddev = div64_ul(stddev,
550 rec->counter * (rec->counter - 1) * 1000);
554 trace_print_graph_duration(rec->time, &s);
555 trace_seq_puts(&s, " ");
556 trace_print_graph_duration(avg, &s);
557 trace_seq_puts(&s, " ");
558 trace_print_graph_duration(stddev, &s);
559 trace_print_seq(m, &s);
563 mutex_unlock(&ftrace_profile_lock);
568 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
570 struct ftrace_profile_page *pg;
572 pg = stat->pages = stat->start;
575 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
580 memset(stat->hash, 0,
581 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
584 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
586 struct ftrace_profile_page *pg;
591 /* If we already allocated, do nothing */
595 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
599 #ifdef CONFIG_DYNAMIC_FTRACE
600 functions = ftrace_update_tot_cnt;
603 * We do not know the number of functions that exist because
604 * dynamic tracing is what counts them. With past experience
605 * we have around 20K functions. That should be more than enough.
606 * It is highly unlikely we will execute every function in
612 pg = stat->start = stat->pages;
614 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
616 for (i = 1; i < pages; i++) {
617 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
628 unsigned long tmp = (unsigned long)pg;
640 static int ftrace_profile_init_cpu(int cpu)
642 struct ftrace_profile_stat *stat;
645 stat = &per_cpu(ftrace_profile_stats, cpu);
648 /* If the profile is already created, simply reset it */
649 ftrace_profile_reset(stat);
654 * We are profiling all functions, but usually only a few thousand
655 * functions are hit. We'll make a hash of 1024 items.
657 size = FTRACE_PROFILE_HASH_SIZE;
659 stat->hash = kcalloc(size, sizeof(struct hlist_head), GFP_KERNEL);
664 /* Preallocate the function profiling pages */
665 if (ftrace_profile_pages_init(stat) < 0) {
674 static int ftrace_profile_init(void)
679 for_each_possible_cpu(cpu) {
680 ret = ftrace_profile_init_cpu(cpu);
688 /* interrupts must be disabled */
689 static struct ftrace_profile *
690 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
692 struct ftrace_profile *rec;
693 struct hlist_head *hhd;
696 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
697 hhd = &stat->hash[key];
699 if (hlist_empty(hhd))
702 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
710 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
711 struct ftrace_profile *rec)
715 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
716 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
720 * The memory is already allocated, this simply finds a new record to use.
722 static struct ftrace_profile *
723 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
725 struct ftrace_profile *rec = NULL;
727 /* prevent recursion (from NMIs) */
728 if (atomic_inc_return(&stat->disabled) != 1)
732 * Try to find the function again since an NMI
733 * could have added it
735 rec = ftrace_find_profiled_func(stat, ip);
739 if (stat->pages->index == PROFILES_PER_PAGE) {
740 if (!stat->pages->next)
742 stat->pages = stat->pages->next;
745 rec = &stat->pages->records[stat->pages->index++];
747 ftrace_add_profile(stat, rec);
750 atomic_dec(&stat->disabled);
756 function_profile_call(unsigned long ip, unsigned long parent_ip,
757 struct ftrace_ops *ops, struct ftrace_regs *fregs)
759 struct ftrace_profile_stat *stat;
760 struct ftrace_profile *rec;
763 if (!ftrace_profile_enabled)
766 local_irq_save(flags);
768 stat = this_cpu_ptr(&ftrace_profile_stats);
769 if (!stat->hash || !ftrace_profile_enabled)
772 rec = ftrace_find_profiled_func(stat, ip);
774 rec = ftrace_profile_alloc(stat, ip);
781 local_irq_restore(flags);
784 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
785 static bool fgraph_graph_time = true;
787 void ftrace_graph_graph_time_control(bool enable)
789 fgraph_graph_time = enable;
792 static int profile_graph_entry(struct ftrace_graph_ent *trace)
794 struct ftrace_ret_stack *ret_stack;
796 function_profile_call(trace->func, 0, NULL, NULL);
798 /* If function graph is shutting down, ret_stack can be NULL */
799 if (!current->ret_stack)
802 ret_stack = ftrace_graph_get_ret_stack(current, 0);
804 ret_stack->subtime = 0;
809 static void profile_graph_return(struct ftrace_graph_ret *trace)
811 struct ftrace_ret_stack *ret_stack;
812 struct ftrace_profile_stat *stat;
813 unsigned long long calltime;
814 struct ftrace_profile *rec;
817 local_irq_save(flags);
818 stat = this_cpu_ptr(&ftrace_profile_stats);
819 if (!stat->hash || !ftrace_profile_enabled)
822 /* If the calltime was zero'd ignore it */
823 if (!trace->calltime)
826 calltime = trace->rettime - trace->calltime;
828 if (!fgraph_graph_time) {
830 /* Append this call time to the parent time to subtract */
831 ret_stack = ftrace_graph_get_ret_stack(current, 1);
833 ret_stack->subtime += calltime;
835 ret_stack = ftrace_graph_get_ret_stack(current, 0);
836 if (ret_stack && ret_stack->subtime < calltime)
837 calltime -= ret_stack->subtime;
842 rec = ftrace_find_profiled_func(stat, trace->func);
844 rec->time += calltime;
845 rec->time_squared += calltime * calltime;
849 local_irq_restore(flags);
852 static struct fgraph_ops fprofiler_ops = {
853 .entryfunc = &profile_graph_entry,
854 .retfunc = &profile_graph_return,
857 static int register_ftrace_profiler(void)
859 return register_ftrace_graph(&fprofiler_ops);
862 static void unregister_ftrace_profiler(void)
864 unregister_ftrace_graph(&fprofiler_ops);
867 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
868 .func = function_profile_call,
869 .flags = FTRACE_OPS_FL_INITIALIZED,
870 INIT_OPS_HASH(ftrace_profile_ops)
873 static int register_ftrace_profiler(void)
875 return register_ftrace_function(&ftrace_profile_ops);
878 static void unregister_ftrace_profiler(void)
880 unregister_ftrace_function(&ftrace_profile_ops);
882 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
885 ftrace_profile_write(struct file *filp, const char __user *ubuf,
886 size_t cnt, loff_t *ppos)
891 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
897 mutex_lock(&ftrace_profile_lock);
898 if (ftrace_profile_enabled ^ val) {
900 ret = ftrace_profile_init();
906 ret = register_ftrace_profiler();
911 ftrace_profile_enabled = 1;
913 ftrace_profile_enabled = 0;
915 * unregister_ftrace_profiler calls stop_machine
916 * so this acts like an synchronize_rcu.
918 unregister_ftrace_profiler();
922 mutex_unlock(&ftrace_profile_lock);
930 ftrace_profile_read(struct file *filp, char __user *ubuf,
931 size_t cnt, loff_t *ppos)
933 char buf[64]; /* big enough to hold a number */
936 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
937 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
940 static const struct file_operations ftrace_profile_fops = {
941 .open = tracing_open_generic,
942 .read = ftrace_profile_read,
943 .write = ftrace_profile_write,
944 .llseek = default_llseek,
947 /* used to initialize the real stat files */
948 static struct tracer_stat function_stats __initdata = {
950 .stat_start = function_stat_start,
951 .stat_next = function_stat_next,
952 .stat_cmp = function_stat_cmp,
953 .stat_headers = function_stat_headers,
954 .stat_show = function_stat_show
957 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
959 struct ftrace_profile_stat *stat;
960 struct dentry *entry;
965 for_each_possible_cpu(cpu) {
966 stat = &per_cpu(ftrace_profile_stats, cpu);
968 name = kasprintf(GFP_KERNEL, "function%d", cpu);
971 * The files created are permanent, if something happens
972 * we still do not free memory.
975 "Could not allocate stat file for cpu %d\n",
979 stat->stat = function_stats;
980 stat->stat.name = name;
981 ret = register_stat_tracer(&stat->stat);
984 "Could not register function stat for cpu %d\n",
991 entry = tracefs_create_file("function_profile_enabled", 0644,
992 d_tracer, NULL, &ftrace_profile_fops);
994 pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
997 #else /* CONFIG_FUNCTION_PROFILER */
998 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1001 #endif /* CONFIG_FUNCTION_PROFILER */
1003 #ifdef CONFIG_DYNAMIC_FTRACE
1005 static struct ftrace_ops *removed_ops;
1008 * Set when doing a global update, like enabling all recs or disabling them.
1009 * It is not set when just updating a single ftrace_ops.
1011 static bool update_all_ops;
1013 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1014 # error Dynamic ftrace depends on MCOUNT_RECORD
1017 struct ftrace_func_probe {
1018 struct ftrace_probe_ops *probe_ops;
1019 struct ftrace_ops ops;
1020 struct trace_array *tr;
1021 struct list_head list;
1027 * We make these constant because no one should touch them,
1028 * but they are used as the default "empty hash", to avoid allocating
1029 * it all the time. These are in a read only section such that if
1030 * anyone does try to modify it, it will cause an exception.
1032 static const struct hlist_head empty_buckets[1];
1033 static const struct ftrace_hash empty_hash = {
1034 .buckets = (struct hlist_head *)empty_buckets,
1036 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1038 struct ftrace_ops global_ops = {
1039 .func = ftrace_stub,
1040 .local_hash.notrace_hash = EMPTY_HASH,
1041 .local_hash.filter_hash = EMPTY_HASH,
1042 INIT_OPS_HASH(global_ops)
1043 .flags = FTRACE_OPS_FL_INITIALIZED |
1048 * Used by the stack unwinder to know about dynamic ftrace trampolines.
1050 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
1052 struct ftrace_ops *op = NULL;
1055 * Some of the ops may be dynamically allocated,
1056 * they are freed after a synchronize_rcu().
1058 preempt_disable_notrace();
1060 do_for_each_ftrace_op(op, ftrace_ops_list) {
1062 * This is to check for dynamically allocated trampolines.
1063 * Trampolines that are in kernel text will have
1064 * core_kernel_text() return true.
1066 if (op->trampoline && op->trampoline_size)
1067 if (addr >= op->trampoline &&
1068 addr < op->trampoline + op->trampoline_size) {
1069 preempt_enable_notrace();
1072 } while_for_each_ftrace_op(op);
1073 preempt_enable_notrace();
1079 * This is used by __kernel_text_address() to return true if the
1080 * address is on a dynamically allocated trampoline that would
1081 * not return true for either core_kernel_text() or
1082 * is_module_text_address().
1084 bool is_ftrace_trampoline(unsigned long addr)
1086 return ftrace_ops_trampoline(addr) != NULL;
1089 struct ftrace_page {
1090 struct ftrace_page *next;
1091 struct dyn_ftrace *records;
1096 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1097 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1099 static struct ftrace_page *ftrace_pages_start;
1100 static struct ftrace_page *ftrace_pages;
1102 static __always_inline unsigned long
1103 ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1105 if (hash->size_bits > 0)
1106 return hash_long(ip, hash->size_bits);
1111 /* Only use this function if ftrace_hash_empty() has already been tested */
1112 static __always_inline struct ftrace_func_entry *
1113 __ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1116 struct ftrace_func_entry *entry;
1117 struct hlist_head *hhd;
1119 key = ftrace_hash_key(hash, ip);
1120 hhd = &hash->buckets[key];
1122 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1123 if (entry->ip == ip)
1130 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1131 * @hash: The hash to look at
1132 * @ip: The instruction pointer to test
1134 * Search a given @hash to see if a given instruction pointer (@ip)
1137 * Returns the entry that holds the @ip if found. NULL otherwise.
1139 struct ftrace_func_entry *
1140 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1142 if (ftrace_hash_empty(hash))
1145 return __ftrace_lookup_ip(hash, ip);
1148 static void __add_hash_entry(struct ftrace_hash *hash,
1149 struct ftrace_func_entry *entry)
1151 struct hlist_head *hhd;
1154 key = ftrace_hash_key(hash, entry->ip);
1155 hhd = &hash->buckets[key];
1156 hlist_add_head(&entry->hlist, hhd);
1160 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1162 struct ftrace_func_entry *entry;
1164 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1169 __add_hash_entry(hash, entry);
1175 free_hash_entry(struct ftrace_hash *hash,
1176 struct ftrace_func_entry *entry)
1178 hlist_del(&entry->hlist);
1184 remove_hash_entry(struct ftrace_hash *hash,
1185 struct ftrace_func_entry *entry)
1187 hlist_del_rcu(&entry->hlist);
1191 static void ftrace_hash_clear(struct ftrace_hash *hash)
1193 struct hlist_head *hhd;
1194 struct hlist_node *tn;
1195 struct ftrace_func_entry *entry;
1196 int size = 1 << hash->size_bits;
1202 for (i = 0; i < size; i++) {
1203 hhd = &hash->buckets[i];
1204 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1205 free_hash_entry(hash, entry);
1207 FTRACE_WARN_ON(hash->count);
1210 static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1212 list_del(&ftrace_mod->list);
1213 kfree(ftrace_mod->module);
1214 kfree(ftrace_mod->func);
1218 static void clear_ftrace_mod_list(struct list_head *head)
1220 struct ftrace_mod_load *p, *n;
1222 /* stack tracer isn't supported yet */
1226 mutex_lock(&ftrace_lock);
1227 list_for_each_entry_safe(p, n, head, list)
1229 mutex_unlock(&ftrace_lock);
1232 static void free_ftrace_hash(struct ftrace_hash *hash)
1234 if (!hash || hash == EMPTY_HASH)
1236 ftrace_hash_clear(hash);
1237 kfree(hash->buckets);
1241 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1243 struct ftrace_hash *hash;
1245 hash = container_of(rcu, struct ftrace_hash, rcu);
1246 free_ftrace_hash(hash);
1249 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1251 if (!hash || hash == EMPTY_HASH)
1253 call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
1256 void ftrace_free_filter(struct ftrace_ops *ops)
1258 ftrace_ops_init(ops);
1259 free_ftrace_hash(ops->func_hash->filter_hash);
1260 free_ftrace_hash(ops->func_hash->notrace_hash);
1263 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1265 struct ftrace_hash *hash;
1268 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1272 size = 1 << size_bits;
1273 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1275 if (!hash->buckets) {
1280 hash->size_bits = size_bits;
1286 static int ftrace_add_mod(struct trace_array *tr,
1287 const char *func, const char *module,
1290 struct ftrace_mod_load *ftrace_mod;
1291 struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1293 ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1297 ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1298 ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1299 ftrace_mod->enable = enable;
1301 if (!ftrace_mod->func || !ftrace_mod->module)
1304 list_add(&ftrace_mod->list, mod_head);
1309 free_ftrace_mod(ftrace_mod);
1314 static struct ftrace_hash *
1315 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1317 struct ftrace_func_entry *entry;
1318 struct ftrace_hash *new_hash;
1323 new_hash = alloc_ftrace_hash(size_bits);
1328 new_hash->flags = hash->flags;
1331 if (ftrace_hash_empty(hash))
1334 size = 1 << hash->size_bits;
1335 for (i = 0; i < size; i++) {
1336 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1337 ret = add_hash_entry(new_hash, entry->ip);
1343 FTRACE_WARN_ON(new_hash->count != hash->count);
1348 free_ftrace_hash(new_hash);
1353 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1355 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1357 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1358 struct ftrace_hash *new_hash);
1360 static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size)
1362 struct ftrace_func_entry *entry;
1363 struct ftrace_hash *new_hash;
1364 struct hlist_head *hhd;
1365 struct hlist_node *tn;
1370 * Use around half the size (max bit of it), but
1371 * a minimum of 2 is fine (as size of 0 or 1 both give 1 for bits).
1373 bits = fls(size / 2);
1375 /* Don't allocate too much */
1376 if (bits > FTRACE_HASH_MAX_BITS)
1377 bits = FTRACE_HASH_MAX_BITS;
1379 new_hash = alloc_ftrace_hash(bits);
1383 new_hash->flags = src->flags;
1385 size = 1 << src->size_bits;
1386 for (i = 0; i < size; i++) {
1387 hhd = &src->buckets[i];
1388 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1389 remove_hash_entry(src, entry);
1390 __add_hash_entry(new_hash, entry);
1396 static struct ftrace_hash *
1397 __ftrace_hash_move(struct ftrace_hash *src)
1399 int size = src->count;
1402 * If the new source is empty, just return the empty_hash.
1404 if (ftrace_hash_empty(src))
1407 return dup_hash(src, size);
1411 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1412 struct ftrace_hash **dst, struct ftrace_hash *src)
1414 struct ftrace_hash *new_hash;
1417 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1418 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1421 new_hash = __ftrace_hash_move(src);
1425 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1427 /* IPMODIFY should be updated only when filter_hash updating */
1428 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1430 free_ftrace_hash(new_hash);
1436 * Remove the current set, update the hash and add
1439 ftrace_hash_rec_disable_modify(ops, enable);
1441 rcu_assign_pointer(*dst, new_hash);
1443 ftrace_hash_rec_enable_modify(ops, enable);
1448 static bool hash_contains_ip(unsigned long ip,
1449 struct ftrace_ops_hash *hash)
1452 * The function record is a match if it exists in the filter
1453 * hash and not in the notrace hash. Note, an empty hash is
1454 * considered a match for the filter hash, but an empty
1455 * notrace hash is considered not in the notrace hash.
1457 return (ftrace_hash_empty(hash->filter_hash) ||
1458 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1459 (ftrace_hash_empty(hash->notrace_hash) ||
1460 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1464 * Test the hashes for this ops to see if we want to call
1465 * the ops->func or not.
1467 * It's a match if the ip is in the ops->filter_hash or
1468 * the filter_hash does not exist or is empty,
1470 * the ip is not in the ops->notrace_hash.
1472 * This needs to be called with preemption disabled as
1473 * the hashes are freed with call_rcu().
1476 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1478 struct ftrace_ops_hash hash;
1481 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1483 * There's a small race when adding ops that the ftrace handler
1484 * that wants regs, may be called without them. We can not
1485 * allow that handler to be called if regs is NULL.
1487 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1491 rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1492 rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1494 if (hash_contains_ip(ip, &hash))
1503 * This is a double for. Do not use 'break' to break out of the loop,
1504 * you must use a goto.
1506 #define do_for_each_ftrace_rec(pg, rec) \
1507 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1509 for (_____i = 0; _____i < pg->index; _____i++) { \
1510 rec = &pg->records[_____i];
1512 #define while_for_each_ftrace_rec() \
1517 static int ftrace_cmp_recs(const void *a, const void *b)
1519 const struct dyn_ftrace *key = a;
1520 const struct dyn_ftrace *rec = b;
1522 if (key->flags < rec->ip)
1524 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1529 static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
1531 struct ftrace_page *pg;
1532 struct dyn_ftrace *rec = NULL;
1533 struct dyn_ftrace key;
1536 key.flags = end; /* overload flags, as it is unsigned long */
1538 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1539 if (end < pg->records[0].ip ||
1540 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1542 rec = bsearch(&key, pg->records, pg->index,
1543 sizeof(struct dyn_ftrace),
1552 * ftrace_location_range - return the first address of a traced location
1553 * if it touches the given ip range
1554 * @start: start of range to search.
1555 * @end: end of range to search (inclusive). @end points to the last byte
1558 * Returns rec->ip if the related ftrace location is a least partly within
1559 * the given address range. That is, the first address of the instruction
1560 * that is either a NOP or call to the function tracer. It checks the ftrace
1561 * internal tables to determine if the address belongs or not.
1563 unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1565 struct dyn_ftrace *rec;
1567 rec = lookup_rec(start, end);
1575 * ftrace_location - return true if the ip giving is a traced location
1576 * @ip: the instruction pointer to check
1578 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1579 * That is, the instruction that is either a NOP or call to
1580 * the function tracer. It checks the ftrace internal tables to
1581 * determine if the address belongs or not.
1583 unsigned long ftrace_location(unsigned long ip)
1585 return ftrace_location_range(ip, ip);
1589 * ftrace_text_reserved - return true if range contains an ftrace location
1590 * @start: start of range to search
1591 * @end: end of range to search (inclusive). @end points to the last byte to check.
1593 * Returns 1 if @start and @end contains a ftrace location.
1594 * That is, the instruction that is either a NOP or call to
1595 * the function tracer. It checks the ftrace internal tables to
1596 * determine if the address belongs or not.
1598 int ftrace_text_reserved(const void *start, const void *end)
1602 ret = ftrace_location_range((unsigned long)start,
1603 (unsigned long)end);
1608 /* Test if ops registered to this rec needs regs */
1609 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1611 struct ftrace_ops *ops;
1612 bool keep_regs = false;
1614 for (ops = ftrace_ops_list;
1615 ops != &ftrace_list_end; ops = ops->next) {
1616 /* pass rec in as regs to have non-NULL val */
1617 if (ftrace_ops_test(ops, rec->ip, rec)) {
1618 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1628 static struct ftrace_ops *
1629 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1630 static struct ftrace_ops *
1631 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude);
1632 static struct ftrace_ops *
1633 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1635 static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1639 struct ftrace_hash *hash;
1640 struct ftrace_hash *other_hash;
1641 struct ftrace_page *pg;
1642 struct dyn_ftrace *rec;
1643 bool update = false;
1647 /* Only update if the ops has been registered */
1648 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1652 * In the filter_hash case:
1653 * If the count is zero, we update all records.
1654 * Otherwise we just update the items in the hash.
1656 * In the notrace_hash case:
1657 * We enable the update in the hash.
1658 * As disabling notrace means enabling the tracing,
1659 * and enabling notrace means disabling, the inc variable
1663 hash = ops->func_hash->filter_hash;
1664 other_hash = ops->func_hash->notrace_hash;
1665 if (ftrace_hash_empty(hash))
1669 hash = ops->func_hash->notrace_hash;
1670 other_hash = ops->func_hash->filter_hash;
1672 * If the notrace hash has no items,
1673 * then there's nothing to do.
1675 if (ftrace_hash_empty(hash))
1679 do_for_each_ftrace_rec(pg, rec) {
1680 int in_other_hash = 0;
1684 if (rec->flags & FTRACE_FL_DISABLED)
1689 * Only the filter_hash affects all records.
1690 * Update if the record is not in the notrace hash.
1692 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1695 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1696 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1699 * If filter_hash is set, we want to match all functions
1700 * that are in the hash but not in the other hash.
1702 * If filter_hash is not set, then we are decrementing.
1703 * That means we match anything that is in the hash
1704 * and also in the other_hash. That is, we need to turn
1705 * off functions in the other hash because they are disabled
1708 if (filter_hash && in_hash && !in_other_hash)
1710 else if (!filter_hash && in_hash &&
1711 (in_other_hash || ftrace_hash_empty(other_hash)))
1719 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1722 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1723 rec->flags |= FTRACE_FL_DIRECT;
1726 * If there's only a single callback registered to a
1727 * function, and the ops has a trampoline registered
1728 * for it, then we can call it directly.
1730 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1731 rec->flags |= FTRACE_FL_TRAMP;
1734 * If we are adding another function callback
1735 * to this function, and the previous had a
1736 * custom trampoline in use, then we need to go
1737 * back to the default trampoline.
1739 rec->flags &= ~FTRACE_FL_TRAMP;
1742 * If any ops wants regs saved for this function
1743 * then all ops will get saved regs.
1745 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1746 rec->flags |= FTRACE_FL_REGS;
1748 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1753 * Only the internal direct_ops should have the
1754 * DIRECT flag set. Thus, if it is removing a
1755 * function, then that function should no longer
1758 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1759 rec->flags &= ~FTRACE_FL_DIRECT;
1762 * If the rec had REGS enabled and the ops that is
1763 * being removed had REGS set, then see if there is
1764 * still any ops for this record that wants regs.
1765 * If not, we can stop recording them.
1767 if (ftrace_rec_count(rec) > 0 &&
1768 rec->flags & FTRACE_FL_REGS &&
1769 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1770 if (!test_rec_ops_needs_regs(rec))
1771 rec->flags &= ~FTRACE_FL_REGS;
1775 * The TRAMP needs to be set only if rec count
1776 * is decremented to one, and the ops that is
1777 * left has a trampoline. As TRAMP can only be
1778 * enabled if there is only a single ops attached
1781 if (ftrace_rec_count(rec) == 1 &&
1782 ftrace_find_tramp_ops_any_other(rec, ops))
1783 rec->flags |= FTRACE_FL_TRAMP;
1785 rec->flags &= ~FTRACE_FL_TRAMP;
1788 * flags will be cleared in ftrace_check_record()
1789 * if rec count is zero.
1794 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1795 update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1797 /* Shortcut, if we handled all records, we are done. */
1798 if (!all && count == hash->count)
1800 } while_for_each_ftrace_rec();
1805 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1808 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1811 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1814 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1817 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1818 int filter_hash, int inc)
1820 struct ftrace_ops *op;
1822 __ftrace_hash_rec_update(ops, filter_hash, inc);
1824 if (ops->func_hash != &global_ops.local_hash)
1828 * If the ops shares the global_ops hash, then we need to update
1829 * all ops that are enabled and use this hash.
1831 do_for_each_ftrace_op(op, ftrace_ops_list) {
1835 if (op->func_hash == &global_ops.local_hash)
1836 __ftrace_hash_rec_update(op, filter_hash, inc);
1837 } while_for_each_ftrace_op(op);
1840 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1843 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1846 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1849 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1853 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1854 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1855 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1856 * Note that old_hash and new_hash has below meanings
1857 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1858 * - If the hash is EMPTY_HASH, it hits nothing
1859 * - Anything else hits the recs which match the hash entries.
1861 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1862 struct ftrace_hash *old_hash,
1863 struct ftrace_hash *new_hash)
1865 struct ftrace_page *pg;
1866 struct dyn_ftrace *rec, *end = NULL;
1869 /* Only update if the ops has been registered */
1870 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1873 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1877 * Since the IPMODIFY is a very address sensitive action, we do not
1878 * allow ftrace_ops to set all functions to new hash.
1880 if (!new_hash || !old_hash)
1883 /* Update rec->flags */
1884 do_for_each_ftrace_rec(pg, rec) {
1886 if (rec->flags & FTRACE_FL_DISABLED)
1889 /* We need to update only differences of filter_hash */
1890 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1891 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1892 if (in_old == in_new)
1896 /* New entries must ensure no others are using it */
1897 if (rec->flags & FTRACE_FL_IPMODIFY)
1899 rec->flags |= FTRACE_FL_IPMODIFY;
1900 } else /* Removed entry */
1901 rec->flags &= ~FTRACE_FL_IPMODIFY;
1902 } while_for_each_ftrace_rec();
1909 /* Roll back what we did above */
1910 do_for_each_ftrace_rec(pg, rec) {
1912 if (rec->flags & FTRACE_FL_DISABLED)
1918 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1919 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1920 if (in_old == in_new)
1924 rec->flags &= ~FTRACE_FL_IPMODIFY;
1926 rec->flags |= FTRACE_FL_IPMODIFY;
1927 } while_for_each_ftrace_rec();
1933 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1935 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1937 if (ftrace_hash_empty(hash))
1940 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1943 /* Disabling always succeeds */
1944 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1946 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1948 if (ftrace_hash_empty(hash))
1951 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1954 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1955 struct ftrace_hash *new_hash)
1957 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1959 if (ftrace_hash_empty(old_hash))
1962 if (ftrace_hash_empty(new_hash))
1965 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
1968 static void print_ip_ins(const char *fmt, const unsigned char *p)
1970 char ins[MCOUNT_INSN_SIZE];
1973 if (copy_from_kernel_nofault(ins, p, MCOUNT_INSN_SIZE)) {
1974 printk(KERN_CONT "%s[FAULT] %px\n", fmt, p);
1978 printk(KERN_CONT "%s", fmt);
1980 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1981 printk(KERN_CONT "%s%02x", i ? ":" : "", ins[i]);
1984 enum ftrace_bug_type ftrace_bug_type;
1985 const void *ftrace_expected;
1987 static void print_bug_type(void)
1989 switch (ftrace_bug_type) {
1990 case FTRACE_BUG_UNKNOWN:
1992 case FTRACE_BUG_INIT:
1993 pr_info("Initializing ftrace call sites\n");
1995 case FTRACE_BUG_NOP:
1996 pr_info("Setting ftrace call site to NOP\n");
1998 case FTRACE_BUG_CALL:
1999 pr_info("Setting ftrace call site to call ftrace function\n");
2001 case FTRACE_BUG_UPDATE:
2002 pr_info("Updating ftrace call site to call a different ftrace function\n");
2008 * ftrace_bug - report and shutdown function tracer
2009 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2010 * @rec: The record that failed
2012 * The arch code that enables or disables the function tracing
2013 * can call ftrace_bug() when it has detected a problem in
2014 * modifying the code. @failed should be one of either:
2015 * EFAULT - if the problem happens on reading the @ip address
2016 * EINVAL - if what is read at @ip is not what was expected
2017 * EPERM - if the problem happens on writing to the @ip address
2019 void ftrace_bug(int failed, struct dyn_ftrace *rec)
2021 unsigned long ip = rec ? rec->ip : 0;
2023 pr_info("------------[ ftrace bug ]------------\n");
2027 pr_info("ftrace faulted on modifying ");
2028 print_ip_sym(KERN_INFO, ip);
2031 pr_info("ftrace failed to modify ");
2032 print_ip_sym(KERN_INFO, ip);
2033 print_ip_ins(" actual: ", (unsigned char *)ip);
2035 if (ftrace_expected) {
2036 print_ip_ins(" expected: ", ftrace_expected);
2041 pr_info("ftrace faulted on writing ");
2042 print_ip_sym(KERN_INFO, ip);
2045 pr_info("ftrace faulted on unknown error ");
2046 print_ip_sym(KERN_INFO, ip);
2050 struct ftrace_ops *ops = NULL;
2052 pr_info("ftrace record flags: %lx\n", rec->flags);
2053 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2054 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2055 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2056 ops = ftrace_find_tramp_ops_any(rec);
2059 pr_cont("\ttramp: %pS (%pS)",
2060 (void *)ops->trampoline,
2062 ops = ftrace_find_tramp_ops_next(rec, ops);
2065 pr_cont("\ttramp: ERROR!");
2068 ip = ftrace_get_addr_curr(rec);
2069 pr_cont("\n expected tramp: %lx\n", ip);
2072 FTRACE_WARN_ON_ONCE(1);
2075 static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2077 unsigned long flag = 0UL;
2079 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2081 if (rec->flags & FTRACE_FL_DISABLED)
2082 return FTRACE_UPDATE_IGNORE;
2085 * If we are updating calls:
2087 * If the record has a ref count, then we need to enable it
2088 * because someone is using it.
2090 * Otherwise we make sure its disabled.
2092 * If we are disabling calls, then disable all records that
2095 if (enable && ftrace_rec_count(rec))
2096 flag = FTRACE_FL_ENABLED;
2099 * If enabling and the REGS flag does not match the REGS_EN, or
2100 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2101 * this record. Set flags to fail the compare against ENABLED.
2102 * Same for direct calls.
2105 if (!(rec->flags & FTRACE_FL_REGS) !=
2106 !(rec->flags & FTRACE_FL_REGS_EN))
2107 flag |= FTRACE_FL_REGS;
2109 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2110 !(rec->flags & FTRACE_FL_TRAMP_EN))
2111 flag |= FTRACE_FL_TRAMP;
2114 * Direct calls are special, as count matters.
2115 * We must test the record for direct, if the
2116 * DIRECT and DIRECT_EN do not match, but only
2117 * if the count is 1. That's because, if the
2118 * count is something other than one, we do not
2119 * want the direct enabled (it will be done via the
2120 * direct helper). But if DIRECT_EN is set, and
2121 * the count is not one, we need to clear it.
2123 if (ftrace_rec_count(rec) == 1) {
2124 if (!(rec->flags & FTRACE_FL_DIRECT) !=
2125 !(rec->flags & FTRACE_FL_DIRECT_EN))
2126 flag |= FTRACE_FL_DIRECT;
2127 } else if (rec->flags & FTRACE_FL_DIRECT_EN) {
2128 flag |= FTRACE_FL_DIRECT;
2132 /* If the state of this record hasn't changed, then do nothing */
2133 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2134 return FTRACE_UPDATE_IGNORE;
2137 /* Save off if rec is being enabled (for return value) */
2138 flag ^= rec->flags & FTRACE_FL_ENABLED;
2141 rec->flags |= FTRACE_FL_ENABLED;
2142 if (flag & FTRACE_FL_REGS) {
2143 if (rec->flags & FTRACE_FL_REGS)
2144 rec->flags |= FTRACE_FL_REGS_EN;
2146 rec->flags &= ~FTRACE_FL_REGS_EN;
2148 if (flag & FTRACE_FL_TRAMP) {
2149 if (rec->flags & FTRACE_FL_TRAMP)
2150 rec->flags |= FTRACE_FL_TRAMP_EN;
2152 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2155 if (flag & FTRACE_FL_DIRECT) {
2157 * If there's only one user (direct_ops helper)
2158 * then we can call the direct function
2159 * directly (no ftrace trampoline).
2161 if (ftrace_rec_count(rec) == 1) {
2162 if (rec->flags & FTRACE_FL_DIRECT)
2163 rec->flags |= FTRACE_FL_DIRECT_EN;
2165 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2168 * Can only call directly if there's
2169 * only one callback to the function.
2171 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2177 * If this record is being updated from a nop, then
2178 * return UPDATE_MAKE_CALL.
2180 * return UPDATE_MODIFY_CALL to tell the caller to convert
2181 * from the save regs, to a non-save regs function or
2182 * vice versa, or from a trampoline call.
2184 if (flag & FTRACE_FL_ENABLED) {
2185 ftrace_bug_type = FTRACE_BUG_CALL;
2186 return FTRACE_UPDATE_MAKE_CALL;
2189 ftrace_bug_type = FTRACE_BUG_UPDATE;
2190 return FTRACE_UPDATE_MODIFY_CALL;
2194 /* If there's no more users, clear all flags */
2195 if (!ftrace_rec_count(rec))
2199 * Just disable the record, but keep the ops TRAMP
2200 * and REGS states. The _EN flags must be disabled though.
2202 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2203 FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN);
2206 ftrace_bug_type = FTRACE_BUG_NOP;
2207 return FTRACE_UPDATE_MAKE_NOP;
2211 * ftrace_update_record, set a record that now is tracing or not
2212 * @rec: the record to update
2213 * @enable: set to true if the record is tracing, false to force disable
2215 * The records that represent all functions that can be traced need
2216 * to be updated when tracing has been enabled.
2218 int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2220 return ftrace_check_record(rec, enable, true);
2224 * ftrace_test_record, check if the record has been enabled or not
2225 * @rec: the record to test
2226 * @enable: set to true to check if enabled, false if it is disabled
2228 * The arch code may need to test if a record is already set to
2229 * tracing to determine how to modify the function code that it
2232 int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2234 return ftrace_check_record(rec, enable, false);
2237 static struct ftrace_ops *
2238 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2240 struct ftrace_ops *op;
2241 unsigned long ip = rec->ip;
2243 do_for_each_ftrace_op(op, ftrace_ops_list) {
2245 if (!op->trampoline)
2248 if (hash_contains_ip(ip, op->func_hash))
2250 } while_for_each_ftrace_op(op);
2255 static struct ftrace_ops *
2256 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude)
2258 struct ftrace_ops *op;
2259 unsigned long ip = rec->ip;
2261 do_for_each_ftrace_op(op, ftrace_ops_list) {
2263 if (op == op_exclude || !op->trampoline)
2266 if (hash_contains_ip(ip, op->func_hash))
2268 } while_for_each_ftrace_op(op);
2273 static struct ftrace_ops *
2274 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2275 struct ftrace_ops *op)
2277 unsigned long ip = rec->ip;
2279 while_for_each_ftrace_op(op) {
2281 if (!op->trampoline)
2284 if (hash_contains_ip(ip, op->func_hash))
2291 static struct ftrace_ops *
2292 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2294 struct ftrace_ops *op;
2295 unsigned long ip = rec->ip;
2298 * Need to check removed ops first.
2299 * If they are being removed, and this rec has a tramp,
2300 * and this rec is in the ops list, then it would be the
2301 * one with the tramp.
2304 if (hash_contains_ip(ip, &removed_ops->old_hash))
2309 * Need to find the current trampoline for a rec.
2310 * Now, a trampoline is only attached to a rec if there
2311 * was a single 'ops' attached to it. But this can be called
2312 * when we are adding another op to the rec or removing the
2313 * current one. Thus, if the op is being added, we can
2314 * ignore it because it hasn't attached itself to the rec
2317 * If an ops is being modified (hooking to different functions)
2318 * then we don't care about the new functions that are being
2319 * added, just the old ones (that are probably being removed).
2321 * If we are adding an ops to a function that already is using
2322 * a trampoline, it needs to be removed (trampolines are only
2323 * for single ops connected), then an ops that is not being
2324 * modified also needs to be checked.
2326 do_for_each_ftrace_op(op, ftrace_ops_list) {
2328 if (!op->trampoline)
2332 * If the ops is being added, it hasn't gotten to
2333 * the point to be removed from this tree yet.
2335 if (op->flags & FTRACE_OPS_FL_ADDING)
2340 * If the ops is being modified and is in the old
2341 * hash, then it is probably being removed from this
2344 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2345 hash_contains_ip(ip, &op->old_hash))
2348 * If the ops is not being added or modified, and it's
2349 * in its normal filter hash, then this must be the one
2352 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2353 hash_contains_ip(ip, op->func_hash))
2356 } while_for_each_ftrace_op(op);
2361 static struct ftrace_ops *
2362 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2364 struct ftrace_ops *op;
2365 unsigned long ip = rec->ip;
2367 do_for_each_ftrace_op(op, ftrace_ops_list) {
2368 /* pass rec in as regs to have non-NULL val */
2369 if (hash_contains_ip(ip, op->func_hash))
2371 } while_for_each_ftrace_op(op);
2376 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
2377 /* Protected by rcu_tasks for reading, and direct_mutex for writing */
2378 static struct ftrace_hash *direct_functions = EMPTY_HASH;
2379 static DEFINE_MUTEX(direct_mutex);
2380 int ftrace_direct_func_count;
2383 * Search the direct_functions hash to see if the given instruction pointer
2384 * has a direct caller attached to it.
2386 unsigned long ftrace_find_rec_direct(unsigned long ip)
2388 struct ftrace_func_entry *entry;
2390 entry = __ftrace_lookup_ip(direct_functions, ip);
2394 return entry->direct;
2397 static void call_direct_funcs(unsigned long ip, unsigned long pip,
2398 struct ftrace_ops *ops, struct ftrace_regs *fregs)
2400 struct pt_regs *regs = ftrace_get_regs(fregs);
2403 addr = ftrace_find_rec_direct(ip);
2407 arch_ftrace_set_direct_caller(regs, addr);
2410 struct ftrace_ops direct_ops = {
2411 .func = call_direct_funcs,
2412 .flags = FTRACE_OPS_FL_IPMODIFY
2413 | FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
2414 | FTRACE_OPS_FL_PERMANENT,
2416 * By declaring the main trampoline as this trampoline
2417 * it will never have one allocated for it. Allocated
2418 * trampolines should not call direct functions.
2419 * The direct_ops should only be called by the builtin
2420 * ftrace_regs_caller trampoline.
2422 .trampoline = FTRACE_REGS_ADDR,
2424 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
2427 * ftrace_get_addr_new - Get the call address to set to
2428 * @rec: The ftrace record descriptor
2430 * If the record has the FTRACE_FL_REGS set, that means that it
2431 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2432 * is not set, then it wants to convert to the normal callback.
2434 * Returns the address of the trampoline to set to
2436 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2438 struct ftrace_ops *ops;
2441 if ((rec->flags & FTRACE_FL_DIRECT) &&
2442 (ftrace_rec_count(rec) == 1)) {
2443 addr = ftrace_find_rec_direct(rec->ip);
2449 /* Trampolines take precedence over regs */
2450 if (rec->flags & FTRACE_FL_TRAMP) {
2451 ops = ftrace_find_tramp_ops_new(rec);
2452 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2453 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2454 (void *)rec->ip, (void *)rec->ip, rec->flags);
2455 /* Ftrace is shutting down, return anything */
2456 return (unsigned long)FTRACE_ADDR;
2458 return ops->trampoline;
2461 if (rec->flags & FTRACE_FL_REGS)
2462 return (unsigned long)FTRACE_REGS_ADDR;
2464 return (unsigned long)FTRACE_ADDR;
2468 * ftrace_get_addr_curr - Get the call address that is already there
2469 * @rec: The ftrace record descriptor
2471 * The FTRACE_FL_REGS_EN is set when the record already points to
2472 * a function that saves all the regs. Basically the '_EN' version
2473 * represents the current state of the function.
2475 * Returns the address of the trampoline that is currently being called
2477 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2479 struct ftrace_ops *ops;
2482 /* Direct calls take precedence over trampolines */
2483 if (rec->flags & FTRACE_FL_DIRECT_EN) {
2484 addr = ftrace_find_rec_direct(rec->ip);
2490 /* Trampolines take precedence over regs */
2491 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2492 ops = ftrace_find_tramp_ops_curr(rec);
2493 if (FTRACE_WARN_ON(!ops)) {
2494 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2495 (void *)rec->ip, (void *)rec->ip);
2496 /* Ftrace is shutting down, return anything */
2497 return (unsigned long)FTRACE_ADDR;
2499 return ops->trampoline;
2502 if (rec->flags & FTRACE_FL_REGS_EN)
2503 return (unsigned long)FTRACE_REGS_ADDR;
2505 return (unsigned long)FTRACE_ADDR;
2509 __ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2511 unsigned long ftrace_old_addr;
2512 unsigned long ftrace_addr;
2515 ftrace_addr = ftrace_get_addr_new(rec);
2517 /* This needs to be done before we call ftrace_update_record */
2518 ftrace_old_addr = ftrace_get_addr_curr(rec);
2520 ret = ftrace_update_record(rec, enable);
2522 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2525 case FTRACE_UPDATE_IGNORE:
2528 case FTRACE_UPDATE_MAKE_CALL:
2529 ftrace_bug_type = FTRACE_BUG_CALL;
2530 return ftrace_make_call(rec, ftrace_addr);
2532 case FTRACE_UPDATE_MAKE_NOP:
2533 ftrace_bug_type = FTRACE_BUG_NOP;
2534 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2536 case FTRACE_UPDATE_MODIFY_CALL:
2537 ftrace_bug_type = FTRACE_BUG_UPDATE;
2538 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2541 return -1; /* unknown ftrace bug */
2544 void __weak ftrace_replace_code(int mod_flags)
2546 struct dyn_ftrace *rec;
2547 struct ftrace_page *pg;
2548 bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2549 int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2552 if (unlikely(ftrace_disabled))
2555 do_for_each_ftrace_rec(pg, rec) {
2557 if (rec->flags & FTRACE_FL_DISABLED)
2560 failed = __ftrace_replace_code(rec, enable);
2562 ftrace_bug(failed, rec);
2563 /* Stop processing */
2568 } while_for_each_ftrace_rec();
2571 struct ftrace_rec_iter {
2572 struct ftrace_page *pg;
2577 * ftrace_rec_iter_start, start up iterating over traced functions
2579 * Returns an iterator handle that is used to iterate over all
2580 * the records that represent address locations where functions
2583 * May return NULL if no records are available.
2585 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2588 * We only use a single iterator.
2589 * Protected by the ftrace_lock mutex.
2591 static struct ftrace_rec_iter ftrace_rec_iter;
2592 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2594 iter->pg = ftrace_pages_start;
2597 /* Could have empty pages */
2598 while (iter->pg && !iter->pg->index)
2599 iter->pg = iter->pg->next;
2608 * ftrace_rec_iter_next, get the next record to process.
2609 * @iter: The handle to the iterator.
2611 * Returns the next iterator after the given iterator @iter.
2613 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2617 if (iter->index >= iter->pg->index) {
2618 iter->pg = iter->pg->next;
2621 /* Could have empty pages */
2622 while (iter->pg && !iter->pg->index)
2623 iter->pg = iter->pg->next;
2633 * ftrace_rec_iter_record, get the record at the iterator location
2634 * @iter: The current iterator location
2636 * Returns the record that the current @iter is at.
2638 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2640 return &iter->pg->records[iter->index];
2644 ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
2648 if (unlikely(ftrace_disabled))
2651 ret = ftrace_init_nop(mod, rec);
2653 ftrace_bug_type = FTRACE_BUG_INIT;
2654 ftrace_bug(ret, rec);
2661 * archs can override this function if they must do something
2662 * before the modifying code is performed.
2664 int __weak ftrace_arch_code_modify_prepare(void)
2670 * archs can override this function if they must do something
2671 * after the modifying code is performed.
2673 int __weak ftrace_arch_code_modify_post_process(void)
2678 void ftrace_modify_all_code(int command)
2680 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2684 if (command & FTRACE_MAY_SLEEP)
2685 mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2688 * If the ftrace_caller calls a ftrace_ops func directly,
2689 * we need to make sure that it only traces functions it
2690 * expects to trace. When doing the switch of functions,
2691 * we need to update to the ftrace_ops_list_func first
2692 * before the transition between old and new calls are set,
2693 * as the ftrace_ops_list_func will check the ops hashes
2694 * to make sure the ops are having the right functions
2698 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2699 if (FTRACE_WARN_ON(err))
2703 if (command & FTRACE_UPDATE_CALLS)
2704 ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2705 else if (command & FTRACE_DISABLE_CALLS)
2706 ftrace_replace_code(mod_flags);
2708 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2709 function_trace_op = set_function_trace_op;
2711 /* If irqs are disabled, we are in stop machine */
2712 if (!irqs_disabled())
2713 smp_call_function(ftrace_sync_ipi, NULL, 1);
2714 err = ftrace_update_ftrace_func(ftrace_trace_function);
2715 if (FTRACE_WARN_ON(err))
2719 if (command & FTRACE_START_FUNC_RET)
2720 err = ftrace_enable_ftrace_graph_caller();
2721 else if (command & FTRACE_STOP_FUNC_RET)
2722 err = ftrace_disable_ftrace_graph_caller();
2723 FTRACE_WARN_ON(err);
2726 static int __ftrace_modify_code(void *data)
2728 int *command = data;
2730 ftrace_modify_all_code(*command);
2736 * ftrace_run_stop_machine, go back to the stop machine method
2737 * @command: The command to tell ftrace what to do
2739 * If an arch needs to fall back to the stop machine method, the
2740 * it can call this function.
2742 void ftrace_run_stop_machine(int command)
2744 stop_machine(__ftrace_modify_code, &command, NULL);
2748 * arch_ftrace_update_code, modify the code to trace or not trace
2749 * @command: The command that needs to be done
2751 * Archs can override this function if it does not need to
2752 * run stop_machine() to modify code.
2754 void __weak arch_ftrace_update_code(int command)
2756 ftrace_run_stop_machine(command);
2759 static void ftrace_run_update_code(int command)
2763 ret = ftrace_arch_code_modify_prepare();
2764 FTRACE_WARN_ON(ret);
2769 * By default we use stop_machine() to modify the code.
2770 * But archs can do what ever they want as long as it
2771 * is safe. The stop_machine() is the safest, but also
2772 * produces the most overhead.
2774 arch_ftrace_update_code(command);
2776 ret = ftrace_arch_code_modify_post_process();
2777 FTRACE_WARN_ON(ret);
2780 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2781 struct ftrace_ops_hash *old_hash)
2783 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2784 ops->old_hash.filter_hash = old_hash->filter_hash;
2785 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2786 ftrace_run_update_code(command);
2787 ops->old_hash.filter_hash = NULL;
2788 ops->old_hash.notrace_hash = NULL;
2789 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2792 static ftrace_func_t saved_ftrace_func;
2793 static int ftrace_start_up;
2795 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2799 /* List of trace_ops that have allocated trampolines */
2800 static LIST_HEAD(ftrace_ops_trampoline_list);
2802 static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops *ops)
2804 lockdep_assert_held(&ftrace_lock);
2805 list_add_rcu(&ops->list, &ftrace_ops_trampoline_list);
2808 static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops)
2810 lockdep_assert_held(&ftrace_lock);
2811 list_del_rcu(&ops->list);
2816 * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols
2817 * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is
2820 #define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace"
2821 #define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"
2823 static void ftrace_trampoline_free(struct ftrace_ops *ops)
2825 if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
2828 * Record the text poke event before the ksymbol unregister
2831 perf_event_text_poke((void *)ops->trampoline,
2832 (void *)ops->trampoline,
2833 ops->trampoline_size, NULL, 0);
2834 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
2835 ops->trampoline, ops->trampoline_size,
2836 true, FTRACE_TRAMPOLINE_SYM);
2837 /* Remove from kallsyms after the perf events */
2838 ftrace_remove_trampoline_from_kallsyms(ops);
2841 arch_ftrace_trampoline_free(ops);
2844 static void ftrace_startup_enable(int command)
2846 if (saved_ftrace_func != ftrace_trace_function) {
2847 saved_ftrace_func = ftrace_trace_function;
2848 command |= FTRACE_UPDATE_TRACE_FUNC;
2851 if (!command || !ftrace_enabled)
2854 ftrace_run_update_code(command);
2857 static void ftrace_startup_all(int command)
2859 update_all_ops = true;
2860 ftrace_startup_enable(command);
2861 update_all_ops = false;
2864 int ftrace_startup(struct ftrace_ops *ops, int command)
2868 if (unlikely(ftrace_disabled))
2871 ret = __register_ftrace_function(ops);
2878 * Note that ftrace probes uses this to start up
2879 * and modify functions it will probe. But we still
2880 * set the ADDING flag for modification, as probes
2881 * do not have trampolines. If they add them in the
2882 * future, then the probes will need to distinguish
2883 * between adding and updating probes.
2885 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2887 ret = ftrace_hash_ipmodify_enable(ops);
2889 /* Rollback registration process */
2890 __unregister_ftrace_function(ops);
2892 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2893 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2894 ftrace_trampoline_free(ops);
2898 if (ftrace_hash_rec_enable(ops, 1))
2899 command |= FTRACE_UPDATE_CALLS;
2901 ftrace_startup_enable(command);
2903 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2908 int ftrace_shutdown(struct ftrace_ops *ops, int command)
2912 if (unlikely(ftrace_disabled))
2915 ret = __unregister_ftrace_function(ops);
2921 * Just warn in case of unbalance, no need to kill ftrace, it's not
2922 * critical but the ftrace_call callers may be never nopped again after
2923 * further ftrace uses.
2925 WARN_ON_ONCE(ftrace_start_up < 0);
2927 /* Disabling ipmodify never fails */
2928 ftrace_hash_ipmodify_disable(ops);
2930 if (ftrace_hash_rec_disable(ops, 1))
2931 command |= FTRACE_UPDATE_CALLS;
2933 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2935 if (saved_ftrace_func != ftrace_trace_function) {
2936 saved_ftrace_func = ftrace_trace_function;
2937 command |= FTRACE_UPDATE_TRACE_FUNC;
2940 if (!command || !ftrace_enabled) {
2942 * If these are dynamic or per_cpu ops, they still
2943 * need their data freed. Since, function tracing is
2944 * not currently active, we can just free them
2945 * without synchronizing all CPUs.
2947 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2954 * If the ops uses a trampoline, then it needs to be
2955 * tested first on update.
2957 ops->flags |= FTRACE_OPS_FL_REMOVING;
2960 /* The trampoline logic checks the old hashes */
2961 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2962 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2964 ftrace_run_update_code(command);
2967 * If there's no more ops registered with ftrace, run a
2968 * sanity check to make sure all rec flags are cleared.
2970 if (rcu_dereference_protected(ftrace_ops_list,
2971 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
2972 struct ftrace_page *pg;
2973 struct dyn_ftrace *rec;
2975 do_for_each_ftrace_rec(pg, rec) {
2976 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
2977 pr_warn(" %pS flags:%lx\n",
2978 (void *)rec->ip, rec->flags);
2979 } while_for_each_ftrace_rec();
2982 ops->old_hash.filter_hash = NULL;
2983 ops->old_hash.notrace_hash = NULL;
2986 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2989 * Dynamic ops may be freed, we must make sure that all
2990 * callers are done before leaving this function.
2991 * The same goes for freeing the per_cpu data of the per_cpu
2994 if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
2996 * We need to do a hard force of sched synchronization.
2997 * This is because we use preempt_disable() to do RCU, but
2998 * the function tracers can be called where RCU is not watching
2999 * (like before user_exit()). We can not rely on the RCU
3000 * infrastructure to do the synchronization, thus we must do it
3003 synchronize_rcu_tasks_rude();
3006 * When the kernel is preemptive, tasks can be preempted
3007 * while on a ftrace trampoline. Just scheduling a task on
3008 * a CPU is not good enough to flush them. Calling
3009 * synchronize_rcu_tasks() will wait for those tasks to
3010 * execute and either schedule voluntarily or enter user space.
3012 if (IS_ENABLED(CONFIG_PREEMPTION))
3013 synchronize_rcu_tasks();
3016 ftrace_trampoline_free(ops);
3022 static void ftrace_startup_sysctl(void)
3026 if (unlikely(ftrace_disabled))
3029 /* Force update next time */
3030 saved_ftrace_func = NULL;
3031 /* ftrace_start_up is true if we want ftrace running */
3032 if (ftrace_start_up) {
3033 command = FTRACE_UPDATE_CALLS;
3034 if (ftrace_graph_active)
3035 command |= FTRACE_START_FUNC_RET;
3036 ftrace_startup_enable(command);
3040 static void ftrace_shutdown_sysctl(void)
3044 if (unlikely(ftrace_disabled))
3047 /* ftrace_start_up is true if ftrace is running */
3048 if (ftrace_start_up) {
3049 command = FTRACE_DISABLE_CALLS;
3050 if (ftrace_graph_active)
3051 command |= FTRACE_STOP_FUNC_RET;
3052 ftrace_run_update_code(command);
3056 static u64 ftrace_update_time;
3057 unsigned long ftrace_update_tot_cnt;
3058 unsigned long ftrace_number_of_pages;
3059 unsigned long ftrace_number_of_groups;
3061 static inline int ops_traces_mod(struct ftrace_ops *ops)
3064 * Filter_hash being empty will default to trace module.
3065 * But notrace hash requires a test of individual module functions.
3067 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
3068 ftrace_hash_empty(ops->func_hash->notrace_hash);
3072 * Check if the current ops references the record.
3074 * If the ops traces all functions, then it was already accounted for.
3075 * If the ops does not trace the current record function, skip it.
3076 * If the ops ignores the function via notrace filter, skip it.
3079 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3081 /* If ops isn't enabled, ignore it */
3082 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
3085 /* If ops traces all then it includes this function */
3086 if (ops_traces_mod(ops))
3089 /* The function must be in the filter */
3090 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
3091 !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
3094 /* If in notrace hash, we ignore it too */
3095 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
3101 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
3103 bool init_nop = ftrace_need_init_nop();
3104 struct ftrace_page *pg;
3105 struct dyn_ftrace *p;
3107 unsigned long update_cnt = 0;
3108 unsigned long rec_flags = 0;
3111 start = ftrace_now(raw_smp_processor_id());
3114 * When a module is loaded, this function is called to convert
3115 * the calls to mcount in its text to nops, and also to create
3116 * an entry in the ftrace data. Now, if ftrace is activated
3117 * after this call, but before the module sets its text to
3118 * read-only, the modification of enabling ftrace can fail if
3119 * the read-only is done while ftrace is converting the calls.
3120 * To prevent this, the module's records are set as disabled
3121 * and will be enabled after the call to set the module's text
3125 rec_flags |= FTRACE_FL_DISABLED;
3127 for (pg = new_pgs; pg; pg = pg->next) {
3129 for (i = 0; i < pg->index; i++) {
3131 /* If something went wrong, bail without enabling anything */
3132 if (unlikely(ftrace_disabled))
3135 p = &pg->records[i];
3136 p->flags = rec_flags;
3139 * Do the initial record conversion from mcount jump
3140 * to the NOP instructions.
3142 if (init_nop && !ftrace_nop_initialize(mod, p))
3149 stop = ftrace_now(raw_smp_processor_id());
3150 ftrace_update_time = stop - start;
3151 ftrace_update_tot_cnt += update_cnt;
3156 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3162 if (WARN_ON(!count))
3165 /* We want to fill as much as possible, with no empty pages */
3166 pages = DIV_ROUND_UP(count, ENTRIES_PER_PAGE);
3167 order = fls(pages) - 1;
3170 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3173 /* if we can't allocate this size, try something smaller */
3180 ftrace_number_of_pages += 1 << order;
3181 ftrace_number_of_groups++;
3183 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3192 static struct ftrace_page *
3193 ftrace_allocate_pages(unsigned long num_to_init)
3195 struct ftrace_page *start_pg;
3196 struct ftrace_page *pg;
3202 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3207 * Try to allocate as much as possible in one continues
3208 * location that fills in all of the space. We want to
3209 * waste as little space as possible.
3212 cnt = ftrace_allocate_records(pg, num_to_init);
3220 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3233 free_pages((unsigned long)pg->records, pg->order);
3234 ftrace_number_of_pages -= 1 << pg->order;
3236 start_pg = pg->next;
3239 ftrace_number_of_groups--;
3241 pr_info("ftrace: FAILED to allocate memory for functions\n");
3245 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3247 struct ftrace_iterator {
3251 struct ftrace_page *pg;
3252 struct dyn_ftrace *func;
3253 struct ftrace_func_probe *probe;
3254 struct ftrace_func_entry *probe_entry;
3255 struct trace_parser parser;
3256 struct ftrace_hash *hash;
3257 struct ftrace_ops *ops;
3258 struct trace_array *tr;
3259 struct list_head *mod_list;
3266 t_probe_next(struct seq_file *m, loff_t *pos)
3268 struct ftrace_iterator *iter = m->private;
3269 struct trace_array *tr = iter->ops->private;
3270 struct list_head *func_probes;
3271 struct ftrace_hash *hash;
3272 struct list_head *next;
3273 struct hlist_node *hnd = NULL;
3274 struct hlist_head *hhd;
3283 func_probes = &tr->func_probes;
3284 if (list_empty(func_probes))
3288 next = func_probes->next;
3289 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3292 if (iter->probe_entry)
3293 hnd = &iter->probe_entry->hlist;
3295 hash = iter->probe->ops.func_hash->filter_hash;
3298 * A probe being registered may temporarily have an empty hash
3299 * and it's at the end of the func_probes list.
3301 if (!hash || hash == EMPTY_HASH)
3304 size = 1 << hash->size_bits;
3307 if (iter->pidx >= size) {
3308 if (iter->probe->list.next == func_probes)
3310 next = iter->probe->list.next;
3311 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3312 hash = iter->probe->ops.func_hash->filter_hash;
3313 size = 1 << hash->size_bits;
3317 hhd = &hash->buckets[iter->pidx];
3319 if (hlist_empty(hhd)) {
3335 if (WARN_ON_ONCE(!hnd))
3338 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3343 static void *t_probe_start(struct seq_file *m, loff_t *pos)
3345 struct ftrace_iterator *iter = m->private;
3349 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3352 if (iter->mod_pos > *pos)
3356 iter->probe_entry = NULL;
3358 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3359 p = t_probe_next(m, &l);
3366 /* Only set this if we have an item */
3367 iter->flags |= FTRACE_ITER_PROBE;
3373 t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3375 struct ftrace_func_entry *probe_entry;
3376 struct ftrace_probe_ops *probe_ops;
3377 struct ftrace_func_probe *probe;
3379 probe = iter->probe;
3380 probe_entry = iter->probe_entry;
3382 if (WARN_ON_ONCE(!probe || !probe_entry))
3385 probe_ops = probe->probe_ops;
3387 if (probe_ops->print)
3388 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3390 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3391 (void *)probe_ops->func);
3397 t_mod_next(struct seq_file *m, loff_t *pos)
3399 struct ftrace_iterator *iter = m->private;
3400 struct trace_array *tr = iter->tr;
3405 iter->mod_list = iter->mod_list->next;
3407 if (iter->mod_list == &tr->mod_trace ||
3408 iter->mod_list == &tr->mod_notrace) {
3409 iter->flags &= ~FTRACE_ITER_MOD;
3413 iter->mod_pos = *pos;
3418 static void *t_mod_start(struct seq_file *m, loff_t *pos)
3420 struct ftrace_iterator *iter = m->private;
3424 if (iter->func_pos > *pos)
3427 iter->mod_pos = iter->func_pos;
3429 /* probes are only available if tr is set */
3433 for (l = 0; l <= (*pos - iter->func_pos); ) {
3434 p = t_mod_next(m, &l);
3439 iter->flags &= ~FTRACE_ITER_MOD;
3440 return t_probe_start(m, pos);
3443 /* Only set this if we have an item */
3444 iter->flags |= FTRACE_ITER_MOD;
3450 t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3452 struct ftrace_mod_load *ftrace_mod;
3453 struct trace_array *tr = iter->tr;
3455 if (WARN_ON_ONCE(!iter->mod_list) ||
3456 iter->mod_list == &tr->mod_trace ||
3457 iter->mod_list == &tr->mod_notrace)
3460 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3462 if (ftrace_mod->func)
3463 seq_printf(m, "%s", ftrace_mod->func);
3467 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3473 t_func_next(struct seq_file *m, loff_t *pos)
3475 struct ftrace_iterator *iter = m->private;
3476 struct dyn_ftrace *rec = NULL;
3481 if (iter->idx >= iter->pg->index) {
3482 if (iter->pg->next) {
3483 iter->pg = iter->pg->next;
3488 rec = &iter->pg->records[iter->idx++];
3489 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3490 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3492 ((iter->flags & FTRACE_ITER_ENABLED) &&
3493 !(rec->flags & FTRACE_FL_ENABLED))) {
3503 iter->pos = iter->func_pos = *pos;
3510 t_next(struct seq_file *m, void *v, loff_t *pos)
3512 struct ftrace_iterator *iter = m->private;
3513 loff_t l = *pos; /* t_probe_start() must use original pos */
3516 if (unlikely(ftrace_disabled))
3519 if (iter->flags & FTRACE_ITER_PROBE)
3520 return t_probe_next(m, pos);
3522 if (iter->flags & FTRACE_ITER_MOD)
3523 return t_mod_next(m, pos);
3525 if (iter->flags & FTRACE_ITER_PRINTALL) {
3526 /* next must increment pos, and t_probe_start does not */
3528 return t_mod_start(m, &l);
3531 ret = t_func_next(m, pos);
3534 return t_mod_start(m, &l);
3539 static void reset_iter_read(struct ftrace_iterator *iter)
3543 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3546 static void *t_start(struct seq_file *m, loff_t *pos)
3548 struct ftrace_iterator *iter = m->private;
3552 mutex_lock(&ftrace_lock);
3554 if (unlikely(ftrace_disabled))
3558 * If an lseek was done, then reset and start from beginning.
3560 if (*pos < iter->pos)
3561 reset_iter_read(iter);
3564 * For set_ftrace_filter reading, if we have the filter
3565 * off, we can short cut and just print out that all
3566 * functions are enabled.
3568 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3569 ftrace_hash_empty(iter->hash)) {
3570 iter->func_pos = 1; /* Account for the message */
3572 return t_mod_start(m, pos);
3573 iter->flags |= FTRACE_ITER_PRINTALL;
3574 /* reset in case of seek/pread */
3575 iter->flags &= ~FTRACE_ITER_PROBE;
3579 if (iter->flags & FTRACE_ITER_MOD)
3580 return t_mod_start(m, pos);
3583 * Unfortunately, we need to restart at ftrace_pages_start
3584 * every time we let go of the ftrace_mutex. This is because
3585 * those pointers can change without the lock.
3587 iter->pg = ftrace_pages_start;
3589 for (l = 0; l <= *pos; ) {
3590 p = t_func_next(m, &l);
3596 return t_mod_start(m, pos);
3601 static void t_stop(struct seq_file *m, void *p)
3603 mutex_unlock(&ftrace_lock);
3607 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3612 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3613 struct dyn_ftrace *rec)
3617 ptr = arch_ftrace_trampoline_func(ops, rec);
3619 seq_printf(m, " ->%pS", ptr);
3622 static int t_show(struct seq_file *m, void *v)
3624 struct ftrace_iterator *iter = m->private;
3625 struct dyn_ftrace *rec;
3627 if (iter->flags & FTRACE_ITER_PROBE)
3628 return t_probe_show(m, iter);
3630 if (iter->flags & FTRACE_ITER_MOD)
3631 return t_mod_show(m, iter);
3633 if (iter->flags & FTRACE_ITER_PRINTALL) {
3634 if (iter->flags & FTRACE_ITER_NOTRACE)
3635 seq_puts(m, "#### no functions disabled ####\n");
3637 seq_puts(m, "#### all functions enabled ####\n");
3646 seq_printf(m, "%ps", (void *)rec->ip);
3647 if (iter->flags & FTRACE_ITER_ENABLED) {
3648 struct ftrace_ops *ops;
3650 seq_printf(m, " (%ld)%s%s%s",
3651 ftrace_rec_count(rec),
3652 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3653 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ",
3654 rec->flags & FTRACE_FL_DIRECT ? " D" : " ");
3655 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3656 ops = ftrace_find_tramp_ops_any(rec);
3659 seq_printf(m, "\ttramp: %pS (%pS)",
3660 (void *)ops->trampoline,
3662 add_trampoline_func(m, ops, rec);
3663 ops = ftrace_find_tramp_ops_next(rec, ops);
3666 seq_puts(m, "\ttramp: ERROR!");
3668 add_trampoline_func(m, NULL, rec);
3670 if (rec->flags & FTRACE_FL_DIRECT) {
3671 unsigned long direct;
3673 direct = ftrace_find_rec_direct(rec->ip);
3675 seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
3684 static const struct seq_operations show_ftrace_seq_ops = {
3692 ftrace_avail_open(struct inode *inode, struct file *file)
3694 struct ftrace_iterator *iter;
3697 ret = security_locked_down(LOCKDOWN_TRACEFS);
3701 if (unlikely(ftrace_disabled))
3704 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3708 iter->pg = ftrace_pages_start;
3709 iter->ops = &global_ops;
3715 ftrace_enabled_open(struct inode *inode, struct file *file)
3717 struct ftrace_iterator *iter;
3720 * This shows us what functions are currently being
3721 * traced and by what. Not sure if we want lockdown
3722 * to hide such critical information for an admin.
3723 * Although, perhaps it can show information we don't
3724 * want people to see, but if something is tracing
3725 * something, we probably want to know about it.
3728 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3732 iter->pg = ftrace_pages_start;
3733 iter->flags = FTRACE_ITER_ENABLED;
3734 iter->ops = &global_ops;
3740 * ftrace_regex_open - initialize function tracer filter files
3741 * @ops: The ftrace_ops that hold the hash filters
3742 * @flag: The type of filter to process
3743 * @inode: The inode, usually passed in to your open routine
3744 * @file: The file, usually passed in to your open routine
3746 * ftrace_regex_open() initializes the filter files for the
3747 * @ops. Depending on @flag it may process the filter hash or
3748 * the notrace hash of @ops. With this called from the open
3749 * routine, you can use ftrace_filter_write() for the write
3750 * routine if @flag has FTRACE_ITER_FILTER set, or
3751 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3752 * tracing_lseek() should be used as the lseek routine, and
3753 * release must call ftrace_regex_release().
3756 ftrace_regex_open(struct ftrace_ops *ops, int flag,
3757 struct inode *inode, struct file *file)
3759 struct ftrace_iterator *iter;
3760 struct ftrace_hash *hash;
3761 struct list_head *mod_head;
3762 struct trace_array *tr = ops->private;
3765 ftrace_ops_init(ops);
3767 if (unlikely(ftrace_disabled))
3770 if (tracing_check_open_get_tr(tr))
3773 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3777 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
3784 mutex_lock(&ops->func_hash->regex_lock);
3786 if (flag & FTRACE_ITER_NOTRACE) {
3787 hash = ops->func_hash->notrace_hash;
3788 mod_head = tr ? &tr->mod_notrace : NULL;
3790 hash = ops->func_hash->filter_hash;
3791 mod_head = tr ? &tr->mod_trace : NULL;
3794 iter->mod_list = mod_head;
3796 if (file->f_mode & FMODE_WRITE) {
3797 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3799 if (file->f_flags & O_TRUNC) {
3800 iter->hash = alloc_ftrace_hash(size_bits);
3801 clear_ftrace_mod_list(mod_head);
3803 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3807 trace_parser_put(&iter->parser);
3815 if (file->f_mode & FMODE_READ) {
3816 iter->pg = ftrace_pages_start;
3818 ret = seq_open(file, &show_ftrace_seq_ops);
3820 struct seq_file *m = file->private_data;
3824 free_ftrace_hash(iter->hash);
3825 trace_parser_put(&iter->parser);
3828 file->private_data = iter;
3831 mutex_unlock(&ops->func_hash->regex_lock);
3837 trace_array_put(tr);
3844 ftrace_filter_open(struct inode *inode, struct file *file)
3846 struct ftrace_ops *ops = inode->i_private;
3848 /* Checks for tracefs lockdown */
3849 return ftrace_regex_open(ops,
3850 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3855 ftrace_notrace_open(struct inode *inode, struct file *file)
3857 struct ftrace_ops *ops = inode->i_private;
3859 /* Checks for tracefs lockdown */
3860 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3864 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3865 struct ftrace_glob {
3872 * If symbols in an architecture don't correspond exactly to the user-visible
3873 * name of what they represent, it is possible to define this function to
3874 * perform the necessary adjustments.
3876 char * __weak arch_ftrace_match_adjust(char *str, const char *search)
3881 static int ftrace_match(char *str, struct ftrace_glob *g)
3886 str = arch_ftrace_match_adjust(str, g->search);
3890 if (strcmp(str, g->search) == 0)
3893 case MATCH_FRONT_ONLY:
3894 if (strncmp(str, g->search, g->len) == 0)
3897 case MATCH_MIDDLE_ONLY:
3898 if (strstr(str, g->search))
3901 case MATCH_END_ONLY:
3903 if (slen >= g->len &&
3904 memcmp(str + slen - g->len, g->search, g->len) == 0)
3908 if (glob_match(g->search, str))
3917 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3919 struct ftrace_func_entry *entry;
3922 entry = ftrace_lookup_ip(hash, rec->ip);
3924 /* Do nothing if it doesn't exist */
3928 free_hash_entry(hash, entry);
3930 /* Do nothing if it exists */
3934 ret = add_hash_entry(hash, rec->ip);
3940 add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
3943 long index = simple_strtoul(func_g->search, NULL, 0);
3944 struct ftrace_page *pg;
3945 struct dyn_ftrace *rec;
3947 /* The index starts at 1 */
3951 do_for_each_ftrace_rec(pg, rec) {
3952 if (pg->index <= index) {
3954 /* this is a double loop, break goes to the next page */
3957 rec = &pg->records[index];
3958 enter_record(hash, rec, clear_filter);
3960 } while_for_each_ftrace_rec();
3965 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3966 struct ftrace_glob *mod_g, int exclude_mod)
3968 char str[KSYM_SYMBOL_LEN];
3971 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3974 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3976 /* blank module name to match all modules */
3978 /* blank module globbing: modname xor exclude_mod */
3979 if (!exclude_mod != !modname)
3985 * exclude_mod is set to trace everything but the given
3986 * module. If it is set and the module matches, then
3987 * return 0. If it is not set, and the module doesn't match
3988 * also return 0. Otherwise, check the function to see if
3991 if (!mod_matches == !exclude_mod)
3994 /* blank search means to match all funcs in the mod */
3999 return ftrace_match(str, func_g);
4003 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
4005 struct ftrace_page *pg;
4006 struct dyn_ftrace *rec;
4007 struct ftrace_glob func_g = { .type = MATCH_FULL };
4008 struct ftrace_glob mod_g = { .type = MATCH_FULL };
4009 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
4010 int exclude_mod = 0;
4013 int clear_filter = 0;
4016 func_g.type = filter_parse_regex(func, len, &func_g.search,
4018 func_g.len = strlen(func_g.search);
4022 mod_g.type = filter_parse_regex(mod, strlen(mod),
4023 &mod_g.search, &exclude_mod);
4024 mod_g.len = strlen(mod_g.search);
4027 mutex_lock(&ftrace_lock);
4029 if (unlikely(ftrace_disabled))
4032 if (func_g.type == MATCH_INDEX) {
4033 found = add_rec_by_index(hash, &func_g, clear_filter);
4037 do_for_each_ftrace_rec(pg, rec) {
4039 if (rec->flags & FTRACE_FL_DISABLED)
4042 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
4043 ret = enter_record(hash, rec, clear_filter);
4050 } while_for_each_ftrace_rec();
4052 mutex_unlock(&ftrace_lock);
4058 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
4060 return match_records(hash, buff, len, NULL);
4063 static void ftrace_ops_update_code(struct ftrace_ops *ops,
4064 struct ftrace_ops_hash *old_hash)
4066 struct ftrace_ops *op;
4068 if (!ftrace_enabled)
4071 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4072 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4077 * If this is the shared global_ops filter, then we need to
4078 * check if there is another ops that shares it, is enabled.
4079 * If so, we still need to run the modify code.
4081 if (ops->func_hash != &global_ops.local_hash)
4084 do_for_each_ftrace_op(op, ftrace_ops_list) {
4085 if (op->func_hash == &global_ops.local_hash &&
4086 op->flags & FTRACE_OPS_FL_ENABLED) {
4087 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4088 /* Only need to do this once */
4091 } while_for_each_ftrace_op(op);
4094 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
4095 struct ftrace_hash **orig_hash,
4096 struct ftrace_hash *hash,
4099 struct ftrace_ops_hash old_hash_ops;
4100 struct ftrace_hash *old_hash;
4103 old_hash = *orig_hash;
4104 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4105 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4106 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4108 ftrace_ops_update_code(ops, &old_hash_ops);
4109 free_ftrace_hash_rcu(old_hash);
4114 static bool module_exists(const char *module)
4116 /* All modules have the symbol __this_module */
4117 static const char this_mod[] = "__this_module";
4118 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
4122 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
4124 if (n > sizeof(modname) - 1)
4127 val = module_kallsyms_lookup_name(modname);
4131 static int cache_mod(struct trace_array *tr,
4132 const char *func, char *module, int enable)
4134 struct ftrace_mod_load *ftrace_mod, *n;
4135 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4138 mutex_lock(&ftrace_lock);
4140 /* We do not cache inverse filters */
4141 if (func[0] == '!') {
4145 /* Look to remove this hash */
4146 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4147 if (strcmp(ftrace_mod->module, module) != 0)
4150 /* no func matches all */
4151 if (strcmp(func, "*") == 0 ||
4152 (ftrace_mod->func &&
4153 strcmp(ftrace_mod->func, func) == 0)) {
4155 free_ftrace_mod(ftrace_mod);
4163 /* We only care about modules that have not been loaded yet */
4164 if (module_exists(module))
4167 /* Save this string off, and execute it when the module is loaded */
4168 ret = ftrace_add_mod(tr, func, module, enable);
4170 mutex_unlock(&ftrace_lock);
4176 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4177 int reset, int enable);
4179 #ifdef CONFIG_MODULES
4180 static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4181 char *mod, bool enable)
4183 struct ftrace_mod_load *ftrace_mod, *n;
4184 struct ftrace_hash **orig_hash, *new_hash;
4185 LIST_HEAD(process_mods);
4188 mutex_lock(&ops->func_hash->regex_lock);
4191 orig_hash = &ops->func_hash->filter_hash;
4193 orig_hash = &ops->func_hash->notrace_hash;
4195 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4198 goto out; /* warn? */
4200 mutex_lock(&ftrace_lock);
4202 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4204 if (strcmp(ftrace_mod->module, mod) != 0)
4207 if (ftrace_mod->func)
4208 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4210 func = kstrdup("*", GFP_KERNEL);
4212 if (!func) /* warn? */
4215 list_move(&ftrace_mod->list, &process_mods);
4217 /* Use the newly allocated func, as it may be "*" */
4218 kfree(ftrace_mod->func);
4219 ftrace_mod->func = func;
4222 mutex_unlock(&ftrace_lock);
4224 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4226 func = ftrace_mod->func;
4228 /* Grabs ftrace_lock, which is why we have this extra step */
4229 match_records(new_hash, func, strlen(func), mod);
4230 free_ftrace_mod(ftrace_mod);
4233 if (enable && list_empty(head))
4234 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4236 mutex_lock(&ftrace_lock);
4238 ftrace_hash_move_and_update_ops(ops, orig_hash,
4240 mutex_unlock(&ftrace_lock);
4243 mutex_unlock(&ops->func_hash->regex_lock);
4245 free_ftrace_hash(new_hash);
4248 static void process_cached_mods(const char *mod_name)
4250 struct trace_array *tr;
4253 mod = kstrdup(mod_name, GFP_KERNEL);
4257 mutex_lock(&trace_types_lock);
4258 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4259 if (!list_empty(&tr->mod_trace))
4260 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4261 if (!list_empty(&tr->mod_notrace))
4262 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4264 mutex_unlock(&trace_types_lock);
4271 * We register the module command as a template to show others how
4272 * to register the a command as well.
4276 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4277 char *func_orig, char *cmd, char *module, int enable)
4282 /* match_records() modifies func, and we need the original */
4283 func = kstrdup(func_orig, GFP_KERNEL);
4288 * cmd == 'mod' because we only registered this func
4289 * for the 'mod' ftrace_func_command.
4290 * But if you register one func with multiple commands,
4291 * you can tell which command was used by the cmd
4294 ret = match_records(hash, func, strlen(func), module);
4298 return cache_mod(tr, func_orig, module, enable);
4304 static struct ftrace_func_command ftrace_mod_cmd = {
4306 .func = ftrace_mod_callback,
4309 static int __init ftrace_mod_cmd_init(void)
4311 return register_ftrace_command(&ftrace_mod_cmd);
4313 core_initcall(ftrace_mod_cmd_init);
4315 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4316 struct ftrace_ops *op, struct ftrace_regs *fregs)
4318 struct ftrace_probe_ops *probe_ops;
4319 struct ftrace_func_probe *probe;
4321 probe = container_of(op, struct ftrace_func_probe, ops);
4322 probe_ops = probe->probe_ops;
4325 * Disable preemption for these calls to prevent a RCU grace
4326 * period. This syncs the hash iteration and freeing of items
4327 * on the hash. rcu_read_lock is too dangerous here.
4329 preempt_disable_notrace();
4330 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4331 preempt_enable_notrace();
4334 struct ftrace_func_map {
4335 struct ftrace_func_entry entry;
4339 struct ftrace_func_mapper {
4340 struct ftrace_hash hash;
4344 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4346 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4348 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4350 struct ftrace_hash *hash;
4353 * The mapper is simply a ftrace_hash, but since the entries
4354 * in the hash are not ftrace_func_entry type, we define it
4355 * as a separate structure.
4357 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4358 return (struct ftrace_func_mapper *)hash;
4362 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4363 * @mapper: The mapper that has the ip maps
4364 * @ip: the instruction pointer to find the data for
4366 * Returns the data mapped to @ip if found otherwise NULL. The return
4367 * is actually the address of the mapper data pointer. The address is
4368 * returned for use cases where the data is no bigger than a long, and
4369 * the user can use the data pointer as its data instead of having to
4370 * allocate more memory for the reference.
4372 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4375 struct ftrace_func_entry *entry;
4376 struct ftrace_func_map *map;
4378 entry = ftrace_lookup_ip(&mapper->hash, ip);
4382 map = (struct ftrace_func_map *)entry;
4387 * ftrace_func_mapper_add_ip - Map some data to an ip
4388 * @mapper: The mapper that has the ip maps
4389 * @ip: The instruction pointer address to map @data to
4390 * @data: The data to map to @ip
4392 * Returns 0 on success otherwise an error.
4394 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4395 unsigned long ip, void *data)
4397 struct ftrace_func_entry *entry;
4398 struct ftrace_func_map *map;
4400 entry = ftrace_lookup_ip(&mapper->hash, ip);
4404 map = kmalloc(sizeof(*map), GFP_KERNEL);
4411 __add_hash_entry(&mapper->hash, &map->entry);
4417 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4418 * @mapper: The mapper that has the ip maps
4419 * @ip: The instruction pointer address to remove the data from
4421 * Returns the data if it is found, otherwise NULL.
4422 * Note, if the data pointer is used as the data itself, (see
4423 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4424 * if the data pointer was set to zero.
4426 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4429 struct ftrace_func_entry *entry;
4430 struct ftrace_func_map *map;
4433 entry = ftrace_lookup_ip(&mapper->hash, ip);
4437 map = (struct ftrace_func_map *)entry;
4440 remove_hash_entry(&mapper->hash, entry);
4447 * free_ftrace_func_mapper - free a mapping of ips and data
4448 * @mapper: The mapper that has the ip maps
4449 * @free_func: A function to be called on each data item.
4451 * This is used to free the function mapper. The @free_func is optional
4452 * and can be used if the data needs to be freed as well.
4454 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4455 ftrace_mapper_func free_func)
4457 struct ftrace_func_entry *entry;
4458 struct ftrace_func_map *map;
4459 struct hlist_head *hhd;
4465 if (free_func && mapper->hash.count) {
4466 size = 1 << mapper->hash.size_bits;
4467 for (i = 0; i < size; i++) {
4468 hhd = &mapper->hash.buckets[i];
4469 hlist_for_each_entry(entry, hhd, hlist) {
4470 map = (struct ftrace_func_map *)entry;
4475 free_ftrace_hash(&mapper->hash);
4478 static void release_probe(struct ftrace_func_probe *probe)
4480 struct ftrace_probe_ops *probe_ops;
4482 mutex_lock(&ftrace_lock);
4484 WARN_ON(probe->ref <= 0);
4486 /* Subtract the ref that was used to protect this instance */
4490 probe_ops = probe->probe_ops;
4492 * Sending zero as ip tells probe_ops to free
4493 * the probe->data itself
4495 if (probe_ops->free)
4496 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4497 list_del(&probe->list);
4500 mutex_unlock(&ftrace_lock);
4503 static void acquire_probe_locked(struct ftrace_func_probe *probe)
4506 * Add one ref to keep it from being freed when releasing the
4507 * ftrace_lock mutex.
4513 register_ftrace_function_probe(char *glob, struct trace_array *tr,
4514 struct ftrace_probe_ops *probe_ops,
4517 struct ftrace_func_entry *entry;
4518 struct ftrace_func_probe *probe;
4519 struct ftrace_hash **orig_hash;
4520 struct ftrace_hash *old_hash;
4521 struct ftrace_hash *hash;
4530 /* We do not support '!' for function probes */
4531 if (WARN_ON(glob[0] == '!'))
4535 mutex_lock(&ftrace_lock);
4536 /* Check if the probe_ops is already registered */
4537 list_for_each_entry(probe, &tr->func_probes, list) {
4538 if (probe->probe_ops == probe_ops)
4541 if (&probe->list == &tr->func_probes) {
4542 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4544 mutex_unlock(&ftrace_lock);
4547 probe->probe_ops = probe_ops;
4548 probe->ops.func = function_trace_probe_call;
4550 ftrace_ops_init(&probe->ops);
4551 list_add(&probe->list, &tr->func_probes);
4554 acquire_probe_locked(probe);
4556 mutex_unlock(&ftrace_lock);
4559 * Note, there's a small window here that the func_hash->filter_hash
4560 * may be NULL or empty. Need to be careful when reading the loop.
4562 mutex_lock(&probe->ops.func_hash->regex_lock);
4564 orig_hash = &probe->ops.func_hash->filter_hash;
4565 old_hash = *orig_hash;
4566 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4573 ret = ftrace_match_records(hash, glob, strlen(glob));
4575 /* Nothing found? */
4582 size = 1 << hash->size_bits;
4583 for (i = 0; i < size; i++) {
4584 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4585 if (ftrace_lookup_ip(old_hash, entry->ip))
4588 * The caller might want to do something special
4589 * for each function we find. We call the callback
4590 * to give the caller an opportunity to do so.
4592 if (probe_ops->init) {
4593 ret = probe_ops->init(probe_ops, tr,
4597 if (probe_ops->free && count)
4598 probe_ops->free(probe_ops, tr,
4608 mutex_lock(&ftrace_lock);
4611 /* Nothing was added? */
4616 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4621 /* One ref for each new function traced */
4622 probe->ref += count;
4624 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4625 ret = ftrace_startup(&probe->ops, 0);
4628 mutex_unlock(&ftrace_lock);
4633 mutex_unlock(&probe->ops.func_hash->regex_lock);
4634 free_ftrace_hash(hash);
4636 release_probe(probe);
4641 if (!probe_ops->free || !count)
4644 /* Failed to do the move, need to call the free functions */
4645 for (i = 0; i < size; i++) {
4646 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4647 if (ftrace_lookup_ip(old_hash, entry->ip))
4649 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4656 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4657 struct ftrace_probe_ops *probe_ops)
4659 struct ftrace_ops_hash old_hash_ops;
4660 struct ftrace_func_entry *entry;
4661 struct ftrace_func_probe *probe;
4662 struct ftrace_glob func_g;
4663 struct ftrace_hash **orig_hash;
4664 struct ftrace_hash *old_hash;
4665 struct ftrace_hash *hash = NULL;
4666 struct hlist_node *tmp;
4667 struct hlist_head hhd;
4668 char str[KSYM_SYMBOL_LEN];
4670 int i, ret = -ENODEV;
4673 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4674 func_g.search = NULL;
4678 func_g.type = filter_parse_regex(glob, strlen(glob),
4679 &func_g.search, ¬);
4680 func_g.len = strlen(func_g.search);
4682 /* we do not support '!' for function probes */
4687 mutex_lock(&ftrace_lock);
4688 /* Check if the probe_ops is already registered */
4689 list_for_each_entry(probe, &tr->func_probes, list) {
4690 if (probe->probe_ops == probe_ops)
4693 if (&probe->list == &tr->func_probes)
4694 goto err_unlock_ftrace;
4697 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4698 goto err_unlock_ftrace;
4700 acquire_probe_locked(probe);
4702 mutex_unlock(&ftrace_lock);
4704 mutex_lock(&probe->ops.func_hash->regex_lock);
4706 orig_hash = &probe->ops.func_hash->filter_hash;
4707 old_hash = *orig_hash;
4709 if (ftrace_hash_empty(old_hash))
4712 old_hash_ops.filter_hash = old_hash;
4713 /* Probes only have filters */
4714 old_hash_ops.notrace_hash = NULL;
4717 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4721 INIT_HLIST_HEAD(&hhd);
4723 size = 1 << hash->size_bits;
4724 for (i = 0; i < size; i++) {
4725 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4727 if (func_g.search) {
4728 kallsyms_lookup(entry->ip, NULL, NULL,
4730 if (!ftrace_match(str, &func_g))
4734 remove_hash_entry(hash, entry);
4735 hlist_add_head(&entry->hlist, &hhd);
4739 /* Nothing found? */
4745 mutex_lock(&ftrace_lock);
4747 WARN_ON(probe->ref < count);
4749 probe->ref -= count;
4751 if (ftrace_hash_empty(hash))
4752 ftrace_shutdown(&probe->ops, 0);
4754 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4757 /* still need to update the function call sites */
4758 if (ftrace_enabled && !ftrace_hash_empty(hash))
4759 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4763 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4764 hlist_del(&entry->hlist);
4765 if (probe_ops->free)
4766 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4769 mutex_unlock(&ftrace_lock);
4772 mutex_unlock(&probe->ops.func_hash->regex_lock);
4773 free_ftrace_hash(hash);
4775 release_probe(probe);
4780 mutex_unlock(&ftrace_lock);
4784 void clear_ftrace_function_probes(struct trace_array *tr)
4786 struct ftrace_func_probe *probe, *n;
4788 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4789 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
4792 static LIST_HEAD(ftrace_commands);
4793 static DEFINE_MUTEX(ftrace_cmd_mutex);
4796 * Currently we only register ftrace commands from __init, so mark this
4799 __init int register_ftrace_command(struct ftrace_func_command *cmd)
4801 struct ftrace_func_command *p;
4804 mutex_lock(&ftrace_cmd_mutex);
4805 list_for_each_entry(p, &ftrace_commands, list) {
4806 if (strcmp(cmd->name, p->name) == 0) {
4811 list_add(&cmd->list, &ftrace_commands);
4813 mutex_unlock(&ftrace_cmd_mutex);
4819 * Currently we only unregister ftrace commands from __init, so mark
4822 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4824 struct ftrace_func_command *p, *n;
4827 mutex_lock(&ftrace_cmd_mutex);
4828 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4829 if (strcmp(cmd->name, p->name) == 0) {
4831 list_del_init(&p->list);
4836 mutex_unlock(&ftrace_cmd_mutex);
4841 static int ftrace_process_regex(struct ftrace_iterator *iter,
4842 char *buff, int len, int enable)
4844 struct ftrace_hash *hash = iter->hash;
4845 struct trace_array *tr = iter->ops->private;
4846 char *func, *command, *next = buff;
4847 struct ftrace_func_command *p;
4850 func = strsep(&next, ":");
4853 ret = ftrace_match_records(hash, func, len);
4863 command = strsep(&next, ":");
4865 mutex_lock(&ftrace_cmd_mutex);
4866 list_for_each_entry(p, &ftrace_commands, list) {
4867 if (strcmp(p->name, command) == 0) {
4868 ret = p->func(tr, hash, func, command, next, enable);
4873 mutex_unlock(&ftrace_cmd_mutex);
4879 ftrace_regex_write(struct file *file, const char __user *ubuf,
4880 size_t cnt, loff_t *ppos, int enable)
4882 struct ftrace_iterator *iter;
4883 struct trace_parser *parser;
4889 if (file->f_mode & FMODE_READ) {
4890 struct seq_file *m = file->private_data;
4893 iter = file->private_data;
4895 if (unlikely(ftrace_disabled))
4898 /* iter->hash is a local copy, so we don't need regex_lock */
4900 parser = &iter->parser;
4901 read = trace_get_user(parser, ubuf, cnt, ppos);
4903 if (read >= 0 && trace_parser_loaded(parser) &&
4904 !trace_parser_cont(parser)) {
4905 ret = ftrace_process_regex(iter, parser->buffer,
4906 parser->idx, enable);
4907 trace_parser_clear(parser);
4918 ftrace_filter_write(struct file *file, const char __user *ubuf,
4919 size_t cnt, loff_t *ppos)
4921 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4925 ftrace_notrace_write(struct file *file, const char __user *ubuf,
4926 size_t cnt, loff_t *ppos)
4928 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4932 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4934 struct ftrace_func_entry *entry;
4936 if (!ftrace_location(ip))
4940 entry = ftrace_lookup_ip(hash, ip);
4943 free_hash_entry(hash, entry);
4947 return add_hash_entry(hash, ip);
4951 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4952 unsigned long ip, int remove, int reset, int enable)
4954 struct ftrace_hash **orig_hash;
4955 struct ftrace_hash *hash;
4958 if (unlikely(ftrace_disabled))
4961 mutex_lock(&ops->func_hash->regex_lock);
4964 orig_hash = &ops->func_hash->filter_hash;
4966 orig_hash = &ops->func_hash->notrace_hash;
4969 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4971 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4975 goto out_regex_unlock;
4978 if (buf && !ftrace_match_records(hash, buf, len)) {
4980 goto out_regex_unlock;
4983 ret = ftrace_match_addr(hash, ip, remove);
4985 goto out_regex_unlock;
4988 mutex_lock(&ftrace_lock);
4989 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
4990 mutex_unlock(&ftrace_lock);
4993 mutex_unlock(&ops->func_hash->regex_lock);
4995 free_ftrace_hash(hash);
5000 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
5001 int reset, int enable)
5003 return ftrace_set_hash(ops, NULL, 0, ip, remove, reset, enable);
5006 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
5008 struct ftrace_direct_func {
5009 struct list_head next;
5014 static LIST_HEAD(ftrace_direct_funcs);
5017 * ftrace_find_direct_func - test an address if it is a registered direct caller
5018 * @addr: The address of a registered direct caller
5020 * This searches to see if a ftrace direct caller has been registered
5021 * at a specific address, and if so, it returns a descriptor for it.
5023 * This can be used by architecture code to see if an address is
5024 * a direct caller (trampoline) attached to a fentry/mcount location.
5025 * This is useful for the function_graph tracer, as it may need to
5026 * do adjustments if it traced a location that also has a direct
5027 * trampoline attached to it.
5029 struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
5031 struct ftrace_direct_func *entry;
5034 /* May be called by fgraph trampoline (protected by rcu tasks) */
5035 list_for_each_entry_rcu(entry, &ftrace_direct_funcs, next) {
5036 if (entry->addr == addr) {
5047 static struct ftrace_direct_func *ftrace_alloc_direct_func(unsigned long addr)
5049 struct ftrace_direct_func *direct;
5051 direct = kmalloc(sizeof(*direct), GFP_KERNEL);
5054 direct->addr = addr;
5056 list_add_rcu(&direct->next, &ftrace_direct_funcs);
5057 ftrace_direct_func_count++;
5062 * register_ftrace_direct - Call a custom trampoline directly
5063 * @ip: The address of the nop at the beginning of a function
5064 * @addr: The address of the trampoline to call at @ip
5066 * This is used to connect a direct call from the nop location (@ip)
5067 * at the start of ftrace traced functions. The location that it calls
5068 * (@addr) must be able to handle a direct call, and save the parameters
5069 * of the function being traced, and restore them (or inject new ones
5070 * if needed), before returning.
5074 * -EBUSY - Another direct function is already attached (there can be only one)
5075 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
5076 * -ENOMEM - There was an allocation failure.
5078 int register_ftrace_direct(unsigned long ip, unsigned long addr)
5080 struct ftrace_direct_func *direct;
5081 struct ftrace_func_entry *entry;
5082 struct ftrace_hash *free_hash = NULL;
5083 struct dyn_ftrace *rec;
5086 mutex_lock(&direct_mutex);
5088 /* See if there's a direct function at @ip already */
5089 if (ftrace_find_rec_direct(ip))
5093 rec = lookup_rec(ip, ip);
5098 * Check if the rec says it has a direct call but we didn't
5101 if (WARN_ON(rec->flags & FTRACE_FL_DIRECT))
5104 /* Make sure the ip points to the exact record */
5105 if (ip != rec->ip) {
5107 /* Need to check this ip for a direct. */
5108 if (ftrace_find_rec_direct(ip))
5113 if (ftrace_hash_empty(direct_functions) ||
5114 direct_functions->count > 2 * (1 << direct_functions->size_bits)) {
5115 struct ftrace_hash *new_hash;
5116 int size = ftrace_hash_empty(direct_functions) ? 0 :
5117 direct_functions->count + 1;
5122 new_hash = dup_hash(direct_functions, size);
5126 free_hash = direct_functions;
5127 direct_functions = new_hash;
5130 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
5134 direct = ftrace_find_direct_func(addr);
5136 direct = ftrace_alloc_direct_func(addr);
5144 entry->direct = addr;
5145 __add_hash_entry(direct_functions, entry);
5147 ret = ftrace_set_filter_ip(&direct_ops, ip, 0, 0);
5149 remove_hash_entry(direct_functions, entry);
5151 if (!ret && !(direct_ops.flags & FTRACE_OPS_FL_ENABLED)) {
5152 ret = register_ftrace_function(&direct_ops);
5154 ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5159 if (!direct->count) {
5160 list_del_rcu(&direct->next);
5161 synchronize_rcu_tasks();
5164 free_ftrace_hash(free_hash);
5166 ftrace_direct_func_count--;
5172 mutex_unlock(&direct_mutex);
5175 synchronize_rcu_tasks();
5176 free_ftrace_hash(free_hash);
5181 EXPORT_SYMBOL_GPL(register_ftrace_direct);
5183 static struct ftrace_func_entry *find_direct_entry(unsigned long *ip,
5184 struct dyn_ftrace **recp)
5186 struct ftrace_func_entry *entry;
5187 struct dyn_ftrace *rec;
5189 rec = lookup_rec(*ip, *ip);
5193 entry = __ftrace_lookup_ip(direct_functions, rec->ip);
5195 WARN_ON(rec->flags & FTRACE_FL_DIRECT);
5199 WARN_ON(!(rec->flags & FTRACE_FL_DIRECT));
5201 /* Passed in ip just needs to be on the call site */
5210 int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
5212 struct ftrace_direct_func *direct;
5213 struct ftrace_func_entry *entry;
5216 mutex_lock(&direct_mutex);
5218 entry = find_direct_entry(&ip, NULL);
5222 if (direct_functions->count == 1)
5223 unregister_ftrace_function(&direct_ops);
5225 ret = ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5229 remove_hash_entry(direct_functions, entry);
5231 direct = ftrace_find_direct_func(addr);
5232 if (!WARN_ON(!direct)) {
5233 /* This is the good path (see the ! before WARN) */
5235 WARN_ON(direct->count < 0);
5236 if (!direct->count) {
5237 list_del_rcu(&direct->next);
5238 synchronize_rcu_tasks();
5241 ftrace_direct_func_count--;
5245 mutex_unlock(&direct_mutex);
5249 EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
5251 static struct ftrace_ops stub_ops = {
5252 .func = ftrace_stub,
5256 * ftrace_modify_direct_caller - modify ftrace nop directly
5257 * @entry: The ftrace hash entry of the direct helper for @rec
5258 * @rec: The record representing the function site to patch
5259 * @old_addr: The location that the site at @rec->ip currently calls
5260 * @new_addr: The location that the site at @rec->ip should call
5262 * An architecture may overwrite this function to optimize the
5263 * changing of the direct callback on an ftrace nop location.
5264 * This is called with the ftrace_lock mutex held, and no other
5265 * ftrace callbacks are on the associated record (@rec). Thus,
5266 * it is safe to modify the ftrace record, where it should be
5267 * currently calling @old_addr directly, to call @new_addr.
5269 * Safety checks should be made to make sure that the code at
5270 * @rec->ip is currently calling @old_addr. And this must
5271 * also update entry->direct to @new_addr.
5273 int __weak ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
5274 struct dyn_ftrace *rec,
5275 unsigned long old_addr,
5276 unsigned long new_addr)
5278 unsigned long ip = rec->ip;
5282 * The ftrace_lock was used to determine if the record
5283 * had more than one registered user to it. If it did,
5284 * we needed to prevent that from changing to do the quick
5285 * switch. But if it did not (only a direct caller was attached)
5286 * then this function is called. But this function can deal
5287 * with attached callers to the rec that we care about, and
5288 * since this function uses standard ftrace calls that take
5289 * the ftrace_lock mutex, we need to release it.
5291 mutex_unlock(&ftrace_lock);
5294 * By setting a stub function at the same address, we force
5295 * the code to call the iterator and the direct_ops helper.
5296 * This means that @ip does not call the direct call, and
5297 * we can simply modify it.
5299 ret = ftrace_set_filter_ip(&stub_ops, ip, 0, 0);
5303 ret = register_ftrace_function(&stub_ops);
5305 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5309 entry->direct = new_addr;
5312 * By removing the stub, we put back the direct call, calling
5315 unregister_ftrace_function(&stub_ops);
5316 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5319 mutex_lock(&ftrace_lock);
5325 * modify_ftrace_direct - Modify an existing direct call to call something else
5326 * @ip: The instruction pointer to modify
5327 * @old_addr: The address that the current @ip calls directly
5328 * @new_addr: The address that the @ip should call
5330 * This modifies a ftrace direct caller at an instruction pointer without
5331 * having to disable it first. The direct call will switch over to the
5332 * @new_addr without missing anything.
5334 * Returns: zero on success. Non zero on error, which includes:
5335 * -ENODEV : the @ip given has no direct caller attached
5336 * -EINVAL : the @old_addr does not match the current direct caller
5338 int modify_ftrace_direct(unsigned long ip,
5339 unsigned long old_addr, unsigned long new_addr)
5341 struct ftrace_direct_func *direct, *new_direct = NULL;
5342 struct ftrace_func_entry *entry;
5343 struct dyn_ftrace *rec;
5346 mutex_lock(&direct_mutex);
5348 mutex_lock(&ftrace_lock);
5349 entry = find_direct_entry(&ip, &rec);
5354 if (entry->direct != old_addr)
5357 direct = ftrace_find_direct_func(old_addr);
5358 if (WARN_ON(!direct))
5360 if (direct->count > 1) {
5362 new_direct = ftrace_alloc_direct_func(new_addr);
5366 new_direct->count++;
5368 direct->addr = new_addr;
5372 * If there's no other ftrace callback on the rec->ip location,
5373 * then it can be changed directly by the architecture.
5374 * If there is another caller, then we just need to change the
5375 * direct caller helper to point to @new_addr.
5377 if (ftrace_rec_count(rec) == 1) {
5378 ret = ftrace_modify_direct_caller(entry, rec, old_addr, new_addr);
5380 entry->direct = new_addr;
5384 if (unlikely(ret && new_direct)) {
5386 list_del_rcu(&new_direct->next);
5387 synchronize_rcu_tasks();
5389 ftrace_direct_func_count--;
5393 mutex_unlock(&ftrace_lock);
5394 mutex_unlock(&direct_mutex);
5397 EXPORT_SYMBOL_GPL(modify_ftrace_direct);
5398 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
5401 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
5402 * @ops - the ops to set the filter with
5403 * @ip - the address to add to or remove from the filter.
5404 * @remove - non zero to remove the ip from the filter
5405 * @reset - non zero to reset all filters before applying this filter.
5407 * Filters denote which functions should be enabled when tracing is enabled
5408 * If @ip is NULL, it fails to update filter.
5410 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
5411 int remove, int reset)
5413 ftrace_ops_init(ops);
5414 return ftrace_set_addr(ops, ip, remove, reset, 1);
5416 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
5419 * ftrace_ops_set_global_filter - setup ops to use global filters
5420 * @ops - the ops which will use the global filters
5422 * ftrace users who need global function trace filtering should call this.
5423 * It can set the global filter only if ops were not initialized before.
5425 void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
5427 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
5430 ftrace_ops_init(ops);
5431 ops->func_hash = &global_ops.local_hash;
5433 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
5436 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
5437 int reset, int enable)
5439 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
5443 * ftrace_set_filter - set a function to filter on in ftrace
5444 * @ops - the ops to set the filter with
5445 * @buf - the string that holds the function filter text.
5446 * @len - the length of the string.
5447 * @reset - non zero to reset all filters before applying this filter.
5449 * Filters denote which functions should be enabled when tracing is enabled.
5450 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5452 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
5455 ftrace_ops_init(ops);
5456 return ftrace_set_regex(ops, buf, len, reset, 1);
5458 EXPORT_SYMBOL_GPL(ftrace_set_filter);
5461 * ftrace_set_notrace - set a function to not trace in ftrace
5462 * @ops - the ops to set the notrace filter with
5463 * @buf - the string that holds the function notrace text.
5464 * @len - the length of the string.
5465 * @reset - non zero to reset all filters before applying this filter.
5467 * Notrace Filters denote which functions should not be enabled when tracing
5468 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5471 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
5474 ftrace_ops_init(ops);
5475 return ftrace_set_regex(ops, buf, len, reset, 0);
5477 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
5479 * ftrace_set_global_filter - set a function to filter on with global tracers
5480 * @buf - the string that holds the function filter text.
5481 * @len - the length of the string.
5482 * @reset - non zero to reset all filters before applying this filter.
5484 * Filters denote which functions should be enabled when tracing is enabled.
5485 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5487 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
5489 ftrace_set_regex(&global_ops, buf, len, reset, 1);
5491 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
5494 * ftrace_set_global_notrace - set a function to not trace with global tracers
5495 * @buf - the string that holds the function notrace text.
5496 * @len - the length of the string.
5497 * @reset - non zero to reset all filters before applying this filter.
5499 * Notrace Filters denote which functions should not be enabled when tracing
5500 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5503 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
5505 ftrace_set_regex(&global_ops, buf, len, reset, 0);
5507 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
5510 * command line interface to allow users to set filters on boot up.
5512 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
5513 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5514 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
5516 /* Used by function selftest to not test if filter is set */
5517 bool ftrace_filter_param __initdata;
5519 static int __init set_ftrace_notrace(char *str)
5521 ftrace_filter_param = true;
5522 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
5525 __setup("ftrace_notrace=", set_ftrace_notrace);
5527 static int __init set_ftrace_filter(char *str)
5529 ftrace_filter_param = true;
5530 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
5533 __setup("ftrace_filter=", set_ftrace_filter);
5535 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5536 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
5537 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5538 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
5540 static int __init set_graph_function(char *str)
5542 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
5545 __setup("ftrace_graph_filter=", set_graph_function);
5547 static int __init set_graph_notrace_function(char *str)
5549 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
5552 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
5554 static int __init set_graph_max_depth_function(char *str)
5558 fgraph_max_depth = simple_strtoul(str, NULL, 0);
5561 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
5563 static void __init set_ftrace_early_graph(char *buf, int enable)
5567 struct ftrace_hash *hash;
5569 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5570 if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
5574 func = strsep(&buf, ",");
5575 /* we allow only one expression at a time */
5576 ret = ftrace_graph_set_hash(hash, func);
5578 printk(KERN_DEBUG "ftrace: function %s not "
5579 "traceable\n", func);
5583 ftrace_graph_hash = hash;
5585 ftrace_graph_notrace_hash = hash;
5587 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5590 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
5594 ftrace_ops_init(ops);
5597 func = strsep(&buf, ",");
5598 ftrace_set_regex(ops, func, strlen(func), 0, enable);
5602 static void __init set_ftrace_early_filters(void)
5604 if (ftrace_filter_buf[0])
5605 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
5606 if (ftrace_notrace_buf[0])
5607 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
5608 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5609 if (ftrace_graph_buf[0])
5610 set_ftrace_early_graph(ftrace_graph_buf, 1);
5611 if (ftrace_graph_notrace_buf[0])
5612 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
5613 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5616 int ftrace_regex_release(struct inode *inode, struct file *file)
5618 struct seq_file *m = (struct seq_file *)file->private_data;
5619 struct ftrace_iterator *iter;
5620 struct ftrace_hash **orig_hash;
5621 struct trace_parser *parser;
5624 if (file->f_mode & FMODE_READ) {
5626 seq_release(inode, file);
5628 iter = file->private_data;
5630 parser = &iter->parser;
5631 if (trace_parser_loaded(parser)) {
5632 int enable = !(iter->flags & FTRACE_ITER_NOTRACE);
5634 ftrace_process_regex(iter, parser->buffer,
5635 parser->idx, enable);
5638 trace_parser_put(parser);
5640 mutex_lock(&iter->ops->func_hash->regex_lock);
5642 if (file->f_mode & FMODE_WRITE) {
5643 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5646 orig_hash = &iter->ops->func_hash->filter_hash;
5647 if (iter->tr && !list_empty(&iter->tr->mod_trace))
5648 iter->hash->flags |= FTRACE_HASH_FL_MOD;
5650 orig_hash = &iter->ops->func_hash->notrace_hash;
5652 mutex_lock(&ftrace_lock);
5653 ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5654 iter->hash, filter_hash);
5655 mutex_unlock(&ftrace_lock);
5657 /* For read only, the hash is the ops hash */
5661 mutex_unlock(&iter->ops->func_hash->regex_lock);
5662 free_ftrace_hash(iter->hash);
5664 trace_array_put(iter->tr);
5670 static const struct file_operations ftrace_avail_fops = {
5671 .open = ftrace_avail_open,
5673 .llseek = seq_lseek,
5674 .release = seq_release_private,
5677 static const struct file_operations ftrace_enabled_fops = {
5678 .open = ftrace_enabled_open,
5680 .llseek = seq_lseek,
5681 .release = seq_release_private,
5684 static const struct file_operations ftrace_filter_fops = {
5685 .open = ftrace_filter_open,
5687 .write = ftrace_filter_write,
5688 .llseek = tracing_lseek,
5689 .release = ftrace_regex_release,
5692 static const struct file_operations ftrace_notrace_fops = {
5693 .open = ftrace_notrace_open,
5695 .write = ftrace_notrace_write,
5696 .llseek = tracing_lseek,
5697 .release = ftrace_regex_release,
5700 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5702 static DEFINE_MUTEX(graph_lock);
5704 struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
5705 struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
5707 enum graph_filter_type {
5708 GRAPH_FILTER_NOTRACE = 0,
5709 GRAPH_FILTER_FUNCTION,
5712 #define FTRACE_GRAPH_EMPTY ((void *)1)
5714 struct ftrace_graph_data {
5715 struct ftrace_hash *hash;
5716 struct ftrace_func_entry *entry;
5717 int idx; /* for hash table iteration */
5718 enum graph_filter_type type;
5719 struct ftrace_hash *new_hash;
5720 const struct seq_operations *seq_ops;
5721 struct trace_parser parser;
5725 __g_next(struct seq_file *m, loff_t *pos)
5727 struct ftrace_graph_data *fgd = m->private;
5728 struct ftrace_func_entry *entry = fgd->entry;
5729 struct hlist_head *head;
5730 int i, idx = fgd->idx;
5732 if (*pos >= fgd->hash->count)
5736 hlist_for_each_entry_continue(entry, hlist) {
5744 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
5745 head = &fgd->hash->buckets[i];
5746 hlist_for_each_entry(entry, head, hlist) {
5756 g_next(struct seq_file *m, void *v, loff_t *pos)
5759 return __g_next(m, pos);
5762 static void *g_start(struct seq_file *m, loff_t *pos)
5764 struct ftrace_graph_data *fgd = m->private;
5766 mutex_lock(&graph_lock);
5768 if (fgd->type == GRAPH_FILTER_FUNCTION)
5769 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5770 lockdep_is_held(&graph_lock));
5772 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5773 lockdep_is_held(&graph_lock));
5775 /* Nothing, tell g_show to print all functions are enabled */
5776 if (ftrace_hash_empty(fgd->hash) && !*pos)
5777 return FTRACE_GRAPH_EMPTY;
5781 return __g_next(m, pos);
5784 static void g_stop(struct seq_file *m, void *p)
5786 mutex_unlock(&graph_lock);
5789 static int g_show(struct seq_file *m, void *v)
5791 struct ftrace_func_entry *entry = v;
5796 if (entry == FTRACE_GRAPH_EMPTY) {
5797 struct ftrace_graph_data *fgd = m->private;
5799 if (fgd->type == GRAPH_FILTER_FUNCTION)
5800 seq_puts(m, "#### all functions enabled ####\n");
5802 seq_puts(m, "#### no functions disabled ####\n");
5806 seq_printf(m, "%ps\n", (void *)entry->ip);
5811 static const struct seq_operations ftrace_graph_seq_ops = {
5819 __ftrace_graph_open(struct inode *inode, struct file *file,
5820 struct ftrace_graph_data *fgd)
5823 struct ftrace_hash *new_hash = NULL;
5825 ret = security_locked_down(LOCKDOWN_TRACEFS);
5829 if (file->f_mode & FMODE_WRITE) {
5830 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
5832 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
5835 if (file->f_flags & O_TRUNC)
5836 new_hash = alloc_ftrace_hash(size_bits);
5838 new_hash = alloc_and_copy_ftrace_hash(size_bits,
5846 if (file->f_mode & FMODE_READ) {
5847 ret = seq_open(file, &ftrace_graph_seq_ops);
5849 struct seq_file *m = file->private_data;
5853 free_ftrace_hash(new_hash);
5857 file->private_data = fgd;
5860 if (ret < 0 && file->f_mode & FMODE_WRITE)
5861 trace_parser_put(&fgd->parser);
5863 fgd->new_hash = new_hash;
5866 * All uses of fgd->hash must be taken with the graph_lock
5867 * held. The graph_lock is going to be released, so force
5868 * fgd->hash to be reinitialized when it is taken again.
5876 ftrace_graph_open(struct inode *inode, struct file *file)
5878 struct ftrace_graph_data *fgd;
5881 if (unlikely(ftrace_disabled))
5884 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5888 mutex_lock(&graph_lock);
5890 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5891 lockdep_is_held(&graph_lock));
5892 fgd->type = GRAPH_FILTER_FUNCTION;
5893 fgd->seq_ops = &ftrace_graph_seq_ops;
5895 ret = __ftrace_graph_open(inode, file, fgd);
5899 mutex_unlock(&graph_lock);
5904 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
5906 struct ftrace_graph_data *fgd;
5909 if (unlikely(ftrace_disabled))
5912 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5916 mutex_lock(&graph_lock);
5918 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5919 lockdep_is_held(&graph_lock));
5920 fgd->type = GRAPH_FILTER_NOTRACE;
5921 fgd->seq_ops = &ftrace_graph_seq_ops;
5923 ret = __ftrace_graph_open(inode, file, fgd);
5927 mutex_unlock(&graph_lock);
5932 ftrace_graph_release(struct inode *inode, struct file *file)
5934 struct ftrace_graph_data *fgd;
5935 struct ftrace_hash *old_hash, *new_hash;
5936 struct trace_parser *parser;
5939 if (file->f_mode & FMODE_READ) {
5940 struct seq_file *m = file->private_data;
5943 seq_release(inode, file);
5945 fgd = file->private_data;
5949 if (file->f_mode & FMODE_WRITE) {
5951 parser = &fgd->parser;
5953 if (trace_parser_loaded((parser))) {
5954 ret = ftrace_graph_set_hash(fgd->new_hash,
5958 trace_parser_put(parser);
5960 new_hash = __ftrace_hash_move(fgd->new_hash);
5966 mutex_lock(&graph_lock);
5968 if (fgd->type == GRAPH_FILTER_FUNCTION) {
5969 old_hash = rcu_dereference_protected(ftrace_graph_hash,
5970 lockdep_is_held(&graph_lock));
5971 rcu_assign_pointer(ftrace_graph_hash, new_hash);
5973 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5974 lockdep_is_held(&graph_lock));
5975 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
5978 mutex_unlock(&graph_lock);
5981 * We need to do a hard force of sched synchronization.
5982 * This is because we use preempt_disable() to do RCU, but
5983 * the function tracers can be called where RCU is not watching
5984 * (like before user_exit()). We can not rely on the RCU
5985 * infrastructure to do the synchronization, thus we must do it
5988 if (old_hash != EMPTY_HASH)
5989 synchronize_rcu_tasks_rude();
5991 free_ftrace_hash(old_hash);
5995 free_ftrace_hash(fgd->new_hash);
6002 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
6004 struct ftrace_glob func_g;
6005 struct dyn_ftrace *rec;
6006 struct ftrace_page *pg;
6007 struct ftrace_func_entry *entry;
6012 func_g.type = filter_parse_regex(buffer, strlen(buffer),
6013 &func_g.search, ¬);
6015 func_g.len = strlen(func_g.search);
6017 mutex_lock(&ftrace_lock);
6019 if (unlikely(ftrace_disabled)) {
6020 mutex_unlock(&ftrace_lock);
6024 do_for_each_ftrace_rec(pg, rec) {
6026 if (rec->flags & FTRACE_FL_DISABLED)
6029 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
6030 entry = ftrace_lookup_ip(hash, rec->ip);
6037 if (add_hash_entry(hash, rec->ip) < 0)
6041 free_hash_entry(hash, entry);
6046 } while_for_each_ftrace_rec();
6048 mutex_unlock(&ftrace_lock);
6057 ftrace_graph_write(struct file *file, const char __user *ubuf,
6058 size_t cnt, loff_t *ppos)
6060 ssize_t read, ret = 0;
6061 struct ftrace_graph_data *fgd = file->private_data;
6062 struct trace_parser *parser;
6067 /* Read mode uses seq functions */
6068 if (file->f_mode & FMODE_READ) {
6069 struct seq_file *m = file->private_data;
6073 parser = &fgd->parser;
6075 read = trace_get_user(parser, ubuf, cnt, ppos);
6077 if (read >= 0 && trace_parser_loaded(parser) &&
6078 !trace_parser_cont(parser)) {
6080 ret = ftrace_graph_set_hash(fgd->new_hash,
6082 trace_parser_clear(parser);
6091 static const struct file_operations ftrace_graph_fops = {
6092 .open = ftrace_graph_open,
6094 .write = ftrace_graph_write,
6095 .llseek = tracing_lseek,
6096 .release = ftrace_graph_release,
6099 static const struct file_operations ftrace_graph_notrace_fops = {
6100 .open = ftrace_graph_notrace_open,
6102 .write = ftrace_graph_write,
6103 .llseek = tracing_lseek,
6104 .release = ftrace_graph_release,
6106 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6108 void ftrace_create_filter_files(struct ftrace_ops *ops,
6109 struct dentry *parent)
6112 trace_create_file("set_ftrace_filter", 0644, parent,
6113 ops, &ftrace_filter_fops);
6115 trace_create_file("set_ftrace_notrace", 0644, parent,
6116 ops, &ftrace_notrace_fops);
6120 * The name "destroy_filter_files" is really a misnomer. Although
6121 * in the future, it may actually delete the files, but this is
6122 * really intended to make sure the ops passed in are disabled
6123 * and that when this function returns, the caller is free to
6126 * The "destroy" name is only to match the "create" name that this
6127 * should be paired with.
6129 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
6131 mutex_lock(&ftrace_lock);
6132 if (ops->flags & FTRACE_OPS_FL_ENABLED)
6133 ftrace_shutdown(ops, 0);
6134 ops->flags |= FTRACE_OPS_FL_DELETED;
6135 ftrace_free_filter(ops);
6136 mutex_unlock(&ftrace_lock);
6139 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
6142 trace_create_file("available_filter_functions", 0444,
6143 d_tracer, NULL, &ftrace_avail_fops);
6145 trace_create_file("enabled_functions", 0444,
6146 d_tracer, NULL, &ftrace_enabled_fops);
6148 ftrace_create_filter_files(&global_ops, d_tracer);
6150 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
6151 trace_create_file("set_graph_function", 0644, d_tracer,
6153 &ftrace_graph_fops);
6154 trace_create_file("set_graph_notrace", 0644, d_tracer,
6156 &ftrace_graph_notrace_fops);
6157 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6162 static int ftrace_cmp_ips(const void *a, const void *b)
6164 const unsigned long *ipa = a;
6165 const unsigned long *ipb = b;
6174 static int ftrace_process_locs(struct module *mod,
6175 unsigned long *start,
6178 struct ftrace_page *start_pg;
6179 struct ftrace_page *pg;
6180 struct dyn_ftrace *rec;
6181 unsigned long count;
6184 unsigned long flags = 0; /* Shut up gcc */
6187 count = end - start;
6192 sort(start, count, sizeof(*start),
6193 ftrace_cmp_ips, NULL);
6195 start_pg = ftrace_allocate_pages(count);
6199 mutex_lock(&ftrace_lock);
6202 * Core and each module needs their own pages, as
6203 * modules will free them when they are removed.
6204 * Force a new page to be allocated for modules.
6207 WARN_ON(ftrace_pages || ftrace_pages_start);
6208 /* First initialization */
6209 ftrace_pages = ftrace_pages_start = start_pg;
6214 if (WARN_ON(ftrace_pages->next)) {
6215 /* Hmm, we have free pages? */
6216 while (ftrace_pages->next)
6217 ftrace_pages = ftrace_pages->next;
6220 ftrace_pages->next = start_pg;
6226 unsigned long end_offset;
6227 addr = ftrace_call_adjust(*p++);
6229 * Some architecture linkers will pad between
6230 * the different mcount_loc sections of different
6231 * object files to satisfy alignments.
6232 * Skip any NULL pointers.
6237 end_offset = (pg->index+1) * sizeof(pg->records[0]);
6238 if (end_offset > PAGE_SIZE << pg->order) {
6239 /* We should have allocated enough */
6240 if (WARN_ON(!pg->next))
6245 rec = &pg->records[pg->index++];
6249 /* We should have used all pages */
6252 /* Assign the last page to ftrace_pages */
6256 * We only need to disable interrupts on start up
6257 * because we are modifying code that an interrupt
6258 * may execute, and the modification is not atomic.
6259 * But for modules, nothing runs the code we modify
6260 * until we are finished with it, and there's no
6261 * reason to cause large interrupt latencies while we do it.
6264 local_irq_save(flags);
6265 ftrace_update_code(mod, start_pg);
6267 local_irq_restore(flags);
6270 mutex_unlock(&ftrace_lock);
6275 struct ftrace_mod_func {
6276 struct list_head list;
6282 struct ftrace_mod_map {
6283 struct rcu_head rcu;
6284 struct list_head list;
6286 unsigned long start_addr;
6287 unsigned long end_addr;
6288 struct list_head funcs;
6289 unsigned int num_funcs;
6292 static int ftrace_get_trampoline_kallsym(unsigned int symnum,
6293 unsigned long *value, char *type,
6294 char *name, char *module_name,
6297 struct ftrace_ops *op;
6299 list_for_each_entry_rcu(op, &ftrace_ops_trampoline_list, list) {
6300 if (!op->trampoline || symnum--)
6302 *value = op->trampoline;
6304 strlcpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
6305 strlcpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
6313 #ifdef CONFIG_MODULES
6315 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
6317 static LIST_HEAD(ftrace_mod_maps);
6319 static int referenced_filters(struct dyn_ftrace *rec)
6321 struct ftrace_ops *ops;
6324 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
6325 if (ops_references_rec(ops, rec)) {
6326 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_DIRECT))
6328 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_IPMODIFY))
6331 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
6332 rec->flags |= FTRACE_FL_REGS;
6333 if (cnt == 1 && ops->trampoline)
6334 rec->flags |= FTRACE_FL_TRAMP;
6336 rec->flags &= ~FTRACE_FL_TRAMP;
6344 clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
6346 struct ftrace_func_entry *entry;
6347 struct dyn_ftrace *rec;
6350 if (ftrace_hash_empty(hash))
6353 for (i = 0; i < pg->index; i++) {
6354 rec = &pg->records[i];
6355 entry = __ftrace_lookup_ip(hash, rec->ip);
6357 * Do not allow this rec to match again.
6358 * Yeah, it may waste some memory, but will be removed
6359 * if/when the hash is modified again.
6366 /* Clear any records from hashes */
6367 static void clear_mod_from_hashes(struct ftrace_page *pg)
6369 struct trace_array *tr;
6371 mutex_lock(&trace_types_lock);
6372 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6373 if (!tr->ops || !tr->ops->func_hash)
6375 mutex_lock(&tr->ops->func_hash->regex_lock);
6376 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
6377 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
6378 mutex_unlock(&tr->ops->func_hash->regex_lock);
6380 mutex_unlock(&trace_types_lock);
6383 static void ftrace_free_mod_map(struct rcu_head *rcu)
6385 struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
6386 struct ftrace_mod_func *mod_func;
6387 struct ftrace_mod_func *n;
6389 /* All the contents of mod_map are now not visible to readers */
6390 list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
6391 kfree(mod_func->name);
6392 list_del(&mod_func->list);
6399 void ftrace_release_mod(struct module *mod)
6401 struct ftrace_mod_map *mod_map;
6402 struct ftrace_mod_map *n;
6403 struct dyn_ftrace *rec;
6404 struct ftrace_page **last_pg;
6405 struct ftrace_page *tmp_page = NULL;
6406 struct ftrace_page *pg;
6408 mutex_lock(&ftrace_lock);
6410 if (ftrace_disabled)
6413 list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
6414 if (mod_map->mod == mod) {
6415 list_del_rcu(&mod_map->list);
6416 call_rcu(&mod_map->rcu, ftrace_free_mod_map);
6422 * Each module has its own ftrace_pages, remove
6423 * them from the list.
6425 last_pg = &ftrace_pages_start;
6426 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
6427 rec = &pg->records[0];
6428 if (within_module_core(rec->ip, mod) ||
6429 within_module_init(rec->ip, mod)) {
6431 * As core pages are first, the first
6432 * page should never be a module page.
6434 if (WARN_ON(pg == ftrace_pages_start))
6437 /* Check if we are deleting the last page */
6438 if (pg == ftrace_pages)
6439 ftrace_pages = next_to_ftrace_page(last_pg);
6441 ftrace_update_tot_cnt -= pg->index;
6442 *last_pg = pg->next;
6444 pg->next = tmp_page;
6447 last_pg = &pg->next;
6450 mutex_unlock(&ftrace_lock);
6452 for (pg = tmp_page; pg; pg = tmp_page) {
6454 /* Needs to be called outside of ftrace_lock */
6455 clear_mod_from_hashes(pg);
6458 free_pages((unsigned long)pg->records, pg->order);
6459 ftrace_number_of_pages -= 1 << pg->order;
6461 tmp_page = pg->next;
6463 ftrace_number_of_groups--;
6467 void ftrace_module_enable(struct module *mod)
6469 struct dyn_ftrace *rec;
6470 struct ftrace_page *pg;
6472 mutex_lock(&ftrace_lock);
6474 if (ftrace_disabled)
6478 * If the tracing is enabled, go ahead and enable the record.
6480 * The reason not to enable the record immediately is the
6481 * inherent check of ftrace_make_nop/ftrace_make_call for
6482 * correct previous instructions. Making first the NOP
6483 * conversion puts the module to the correct state, thus
6484 * passing the ftrace_make_call check.
6486 * We also delay this to after the module code already set the
6487 * text to read-only, as we now need to set it back to read-write
6488 * so that we can modify the text.
6490 if (ftrace_start_up)
6491 ftrace_arch_code_modify_prepare();
6493 do_for_each_ftrace_rec(pg, rec) {
6496 * do_for_each_ftrace_rec() is a double loop.
6497 * module text shares the pg. If a record is
6498 * not part of this module, then skip this pg,
6499 * which the "break" will do.
6501 if (!within_module_core(rec->ip, mod) &&
6502 !within_module_init(rec->ip, mod))
6508 * When adding a module, we need to check if tracers are
6509 * currently enabled and if they are, and can trace this record,
6510 * we need to enable the module functions as well as update the
6511 * reference counts for those function records.
6513 if (ftrace_start_up)
6514 cnt += referenced_filters(rec);
6516 rec->flags &= ~FTRACE_FL_DISABLED;
6519 if (ftrace_start_up && cnt) {
6520 int failed = __ftrace_replace_code(rec, 1);
6522 ftrace_bug(failed, rec);
6527 } while_for_each_ftrace_rec();
6530 if (ftrace_start_up)
6531 ftrace_arch_code_modify_post_process();
6534 mutex_unlock(&ftrace_lock);
6536 process_cached_mods(mod->name);
6539 void ftrace_module_init(struct module *mod)
6541 if (ftrace_disabled || !mod->num_ftrace_callsites)
6544 ftrace_process_locs(mod, mod->ftrace_callsites,
6545 mod->ftrace_callsites + mod->num_ftrace_callsites);
6548 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6549 struct dyn_ftrace *rec)
6551 struct ftrace_mod_func *mod_func;
6552 unsigned long symsize;
6553 unsigned long offset;
6554 char str[KSYM_SYMBOL_LEN];
6558 ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
6562 mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
6566 mod_func->name = kstrdup(str, GFP_KERNEL);
6567 if (!mod_func->name) {
6572 mod_func->ip = rec->ip - offset;
6573 mod_func->size = symsize;
6575 mod_map->num_funcs++;
6577 list_add_rcu(&mod_func->list, &mod_map->funcs);
6580 static struct ftrace_mod_map *
6581 allocate_ftrace_mod_map(struct module *mod,
6582 unsigned long start, unsigned long end)
6584 struct ftrace_mod_map *mod_map;
6586 mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
6591 mod_map->start_addr = start;
6592 mod_map->end_addr = end;
6593 mod_map->num_funcs = 0;
6595 INIT_LIST_HEAD_RCU(&mod_map->funcs);
6597 list_add_rcu(&mod_map->list, &ftrace_mod_maps);
6603 ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
6604 unsigned long addr, unsigned long *size,
6605 unsigned long *off, char *sym)
6607 struct ftrace_mod_func *found_func = NULL;
6608 struct ftrace_mod_func *mod_func;
6610 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6611 if (addr >= mod_func->ip &&
6612 addr < mod_func->ip + mod_func->size) {
6613 found_func = mod_func;
6620 *size = found_func->size;
6622 *off = addr - found_func->ip;
6624 strlcpy(sym, found_func->name, KSYM_NAME_LEN);
6626 return found_func->name;
6633 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
6634 unsigned long *off, char **modname, char *sym)
6636 struct ftrace_mod_map *mod_map;
6637 const char *ret = NULL;
6639 /* mod_map is freed via call_rcu() */
6641 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6642 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
6645 *modname = mod_map->mod->name;
6654 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
6655 char *type, char *name,
6656 char *module_name, int *exported)
6658 struct ftrace_mod_map *mod_map;
6659 struct ftrace_mod_func *mod_func;
6663 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6665 if (symnum >= mod_map->num_funcs) {
6666 symnum -= mod_map->num_funcs;
6670 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6676 *value = mod_func->ip;
6678 strlcpy(name, mod_func->name, KSYM_NAME_LEN);
6679 strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
6687 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
6688 module_name, exported);
6694 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6695 struct dyn_ftrace *rec) { }
6696 static inline struct ftrace_mod_map *
6697 allocate_ftrace_mod_map(struct module *mod,
6698 unsigned long start, unsigned long end)
6702 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
6703 char *type, char *name, char *module_name,
6709 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
6710 module_name, exported);
6714 #endif /* CONFIG_MODULES */
6716 struct ftrace_init_func {
6717 struct list_head list;
6721 /* Clear any init ips from hashes */
6723 clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
6725 struct ftrace_func_entry *entry;
6727 entry = ftrace_lookup_ip(hash, func->ip);
6729 * Do not allow this rec to match again.
6730 * Yeah, it may waste some memory, but will be removed
6731 * if/when the hash is modified again.
6738 clear_func_from_hashes(struct ftrace_init_func *func)
6740 struct trace_array *tr;
6742 mutex_lock(&trace_types_lock);
6743 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6744 if (!tr->ops || !tr->ops->func_hash)
6746 mutex_lock(&tr->ops->func_hash->regex_lock);
6747 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
6748 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
6749 mutex_unlock(&tr->ops->func_hash->regex_lock);
6751 mutex_unlock(&trace_types_lock);
6754 static void add_to_clear_hash_list(struct list_head *clear_list,
6755 struct dyn_ftrace *rec)
6757 struct ftrace_init_func *func;
6759 func = kmalloc(sizeof(*func), GFP_KERNEL);
6761 MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
6766 list_add(&func->list, clear_list);
6769 void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
6771 unsigned long start = (unsigned long)(start_ptr);
6772 unsigned long end = (unsigned long)(end_ptr);
6773 struct ftrace_page **last_pg = &ftrace_pages_start;
6774 struct ftrace_page *pg;
6775 struct dyn_ftrace *rec;
6776 struct dyn_ftrace key;
6777 struct ftrace_mod_map *mod_map = NULL;
6778 struct ftrace_init_func *func, *func_next;
6779 struct list_head clear_hash;
6781 INIT_LIST_HEAD(&clear_hash);
6784 key.flags = end; /* overload flags, as it is unsigned long */
6786 mutex_lock(&ftrace_lock);
6789 * If we are freeing module init memory, then check if
6790 * any tracer is active. If so, we need to save a mapping of
6791 * the module functions being freed with the address.
6793 if (mod && ftrace_ops_list != &ftrace_list_end)
6794 mod_map = allocate_ftrace_mod_map(mod, start, end);
6796 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
6797 if (end < pg->records[0].ip ||
6798 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
6801 rec = bsearch(&key, pg->records, pg->index,
6802 sizeof(struct dyn_ftrace),
6807 /* rec will be cleared from hashes after ftrace_lock unlock */
6808 add_to_clear_hash_list(&clear_hash, rec);
6811 save_ftrace_mod_rec(mod_map, rec);
6814 ftrace_update_tot_cnt--;
6816 *last_pg = pg->next;
6818 free_pages((unsigned long)pg->records, pg->order);
6819 ftrace_number_of_pages -= 1 << pg->order;
6821 ftrace_number_of_groups--;
6823 pg = container_of(last_pg, struct ftrace_page, next);
6828 memmove(rec, rec + 1,
6829 (pg->index - (rec - pg->records)) * sizeof(*rec));
6830 /* More than one function may be in this block */
6833 mutex_unlock(&ftrace_lock);
6835 list_for_each_entry_safe(func, func_next, &clear_hash, list) {
6836 clear_func_from_hashes(func);
6841 void __init ftrace_free_init_mem(void)
6843 void *start = (void *)(&__init_begin);
6844 void *end = (void *)(&__init_end);
6846 ftrace_free_mem(NULL, start, end);
6849 void __init ftrace_init(void)
6851 extern unsigned long __start_mcount_loc[];
6852 extern unsigned long __stop_mcount_loc[];
6853 unsigned long count, flags;
6856 local_irq_save(flags);
6857 ret = ftrace_dyn_arch_init();
6858 local_irq_restore(flags);
6862 count = __stop_mcount_loc - __start_mcount_loc;
6864 pr_info("ftrace: No functions to be traced?\n");
6868 pr_info("ftrace: allocating %ld entries in %ld pages\n",
6869 count, count / ENTRIES_PER_PAGE + 1);
6871 last_ftrace_enabled = ftrace_enabled = 1;
6873 ret = ftrace_process_locs(NULL,
6877 pr_info("ftrace: allocated %ld pages with %ld groups\n",
6878 ftrace_number_of_pages, ftrace_number_of_groups);
6880 set_ftrace_early_filters();
6884 ftrace_disabled = 1;
6887 /* Do nothing if arch does not support this */
6888 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
6892 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6894 unsigned long trampoline = ops->trampoline;
6896 arch_ftrace_update_trampoline(ops);
6897 if (ops->trampoline && ops->trampoline != trampoline &&
6898 (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) {
6899 /* Add to kallsyms before the perf events */
6900 ftrace_add_trampoline_to_kallsyms(ops);
6901 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
6902 ops->trampoline, ops->trampoline_size, false,
6903 FTRACE_TRAMPOLINE_SYM);
6905 * Record the perf text poke event after the ksymbol register
6908 perf_event_text_poke((void *)ops->trampoline, NULL, 0,
6909 (void *)ops->trampoline,
6910 ops->trampoline_size);
6914 void ftrace_init_trace_array(struct trace_array *tr)
6916 INIT_LIST_HEAD(&tr->func_probes);
6917 INIT_LIST_HEAD(&tr->mod_trace);
6918 INIT_LIST_HEAD(&tr->mod_notrace);
6922 struct ftrace_ops global_ops = {
6923 .func = ftrace_stub,
6924 .flags = FTRACE_OPS_FL_INITIALIZED |
6928 static int __init ftrace_nodyn_init(void)
6933 core_initcall(ftrace_nodyn_init);
6935 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
6936 static inline void ftrace_startup_enable(int command) { }
6937 static inline void ftrace_startup_all(int command) { }
6939 # define ftrace_startup_sysctl() do { } while (0)
6940 # define ftrace_shutdown_sysctl() do { } while (0)
6942 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6946 #endif /* CONFIG_DYNAMIC_FTRACE */
6948 __init void ftrace_init_global_array_ops(struct trace_array *tr)
6950 tr->ops = &global_ops;
6951 tr->ops->private = tr;
6952 ftrace_init_trace_array(tr);
6955 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
6957 /* If we filter on pids, update to use the pid function */
6958 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
6959 if (WARN_ON(tr->ops->func != ftrace_stub))
6960 printk("ftrace ops had %pS for function\n",
6963 tr->ops->func = func;
6964 tr->ops->private = tr;
6967 void ftrace_reset_array_ops(struct trace_array *tr)
6969 tr->ops->func = ftrace_stub;
6972 static nokprobe_inline void
6973 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6974 struct ftrace_ops *ignored, struct ftrace_regs *fregs)
6976 struct pt_regs *regs = ftrace_get_regs(fregs);
6977 struct ftrace_ops *op;
6980 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
6985 * Some of the ops may be dynamically allocated,
6986 * they must be freed after a synchronize_rcu().
6988 preempt_disable_notrace();
6990 do_for_each_ftrace_op(op, ftrace_ops_list) {
6991 /* Stub functions don't need to be called nor tested */
6992 if (op->flags & FTRACE_OPS_FL_STUB)
6995 * Check the following for each ops before calling their func:
6996 * if RCU flag is set, then rcu_is_watching() must be true
6997 * if PER_CPU is set, then ftrace_function_local_disable()
6999 * Otherwise test if the ip matches the ops filter
7001 * If any of the above fails then the op->func() is not executed.
7003 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
7004 ftrace_ops_test(op, ip, regs)) {
7005 if (FTRACE_WARN_ON(!op->func)) {
7006 pr_warn("op=%p %pS\n", op, op);
7009 op->func(ip, parent_ip, op, fregs);
7011 } while_for_each_ftrace_op(op);
7013 preempt_enable_notrace();
7014 trace_clear_recursion(bit);
7018 * Some archs only support passing ip and parent_ip. Even though
7019 * the list function ignores the op parameter, we do not want any
7020 * C side effects, where a function is called without the caller
7021 * sending a third parameter.
7022 * Archs are to support both the regs and ftrace_ops at the same time.
7023 * If they support ftrace_ops, it is assumed they support regs.
7024 * If call backs want to use regs, they must either check for regs
7025 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
7026 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
7027 * An architecture can pass partial regs with ftrace_ops and still
7028 * set the ARCH_SUPPORTS_FTRACE_OPS.
7030 #if ARCH_SUPPORTS_FTRACE_OPS
7031 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7032 struct ftrace_ops *op, struct ftrace_regs *fregs)
7034 __ftrace_ops_list_func(ip, parent_ip, NULL, fregs);
7036 NOKPROBE_SYMBOL(ftrace_ops_list_func);
7038 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
7040 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
7042 NOKPROBE_SYMBOL(ftrace_ops_no_ops);
7046 * If there's only one function registered but it does not support
7047 * recursion, needs RCU protection and/or requires per cpu handling, then
7048 * this function will be called by the mcount trampoline.
7050 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
7051 struct ftrace_ops *op, struct ftrace_regs *fregs)
7055 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7059 preempt_disable_notrace();
7061 if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
7062 op->func(ip, parent_ip, op, fregs);
7064 preempt_enable_notrace();
7065 trace_clear_recursion(bit);
7067 NOKPROBE_SYMBOL(ftrace_ops_assist_func);
7070 * ftrace_ops_get_func - get the function a trampoline should call
7071 * @ops: the ops to get the function for
7073 * Normally the mcount trampoline will call the ops->func, but there
7074 * are times that it should not. For example, if the ops does not
7075 * have its own recursion protection, then it should call the
7076 * ftrace_ops_assist_func() instead.
7078 * Returns the function that the trampoline should call for @ops.
7080 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
7083 * If the function does not handle recursion or needs to be RCU safe,
7084 * then we need to call the assist handler.
7086 if (ops->flags & (FTRACE_OPS_FL_RECURSION |
7088 return ftrace_ops_assist_func;
7094 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
7095 struct task_struct *prev, struct task_struct *next)
7097 struct trace_array *tr = data;
7098 struct trace_pid_list *pid_list;
7099 struct trace_pid_list *no_pid_list;
7101 pid_list = rcu_dereference_sched(tr->function_pids);
7102 no_pid_list = rcu_dereference_sched(tr->function_no_pids);
7104 if (trace_ignore_this_task(pid_list, no_pid_list, next))
7105 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7108 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7113 ftrace_pid_follow_sched_process_fork(void *data,
7114 struct task_struct *self,
7115 struct task_struct *task)
7117 struct trace_pid_list *pid_list;
7118 struct trace_array *tr = data;
7120 pid_list = rcu_dereference_sched(tr->function_pids);
7121 trace_filter_add_remove_task(pid_list, self, task);
7123 pid_list = rcu_dereference_sched(tr->function_no_pids);
7124 trace_filter_add_remove_task(pid_list, self, task);
7128 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
7130 struct trace_pid_list *pid_list;
7131 struct trace_array *tr = data;
7133 pid_list = rcu_dereference_sched(tr->function_pids);
7134 trace_filter_add_remove_task(pid_list, NULL, task);
7136 pid_list = rcu_dereference_sched(tr->function_no_pids);
7137 trace_filter_add_remove_task(pid_list, NULL, task);
7140 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
7143 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7145 register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7148 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7150 unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7155 static void clear_ftrace_pids(struct trace_array *tr, int type)
7157 struct trace_pid_list *pid_list;
7158 struct trace_pid_list *no_pid_list;
7161 pid_list = rcu_dereference_protected(tr->function_pids,
7162 lockdep_is_held(&ftrace_lock));
7163 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7164 lockdep_is_held(&ftrace_lock));
7166 /* Make sure there's something to do */
7167 if (!pid_type_enabled(type, pid_list, no_pid_list))
7170 /* See if the pids still need to be checked after this */
7171 if (!still_need_pid_events(type, pid_list, no_pid_list)) {
7172 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7173 for_each_possible_cpu(cpu)
7174 per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
7177 if (type & TRACE_PIDS)
7178 rcu_assign_pointer(tr->function_pids, NULL);
7180 if (type & TRACE_NO_PIDS)
7181 rcu_assign_pointer(tr->function_no_pids, NULL);
7183 /* Wait till all users are no longer using pid filtering */
7186 if ((type & TRACE_PIDS) && pid_list)
7187 trace_free_pid_list(pid_list);
7189 if ((type & TRACE_NO_PIDS) && no_pid_list)
7190 trace_free_pid_list(no_pid_list);
7193 void ftrace_clear_pids(struct trace_array *tr)
7195 mutex_lock(&ftrace_lock);
7197 clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
7199 mutex_unlock(&ftrace_lock);
7202 static void ftrace_pid_reset(struct trace_array *tr, int type)
7204 mutex_lock(&ftrace_lock);
7205 clear_ftrace_pids(tr, type);
7207 ftrace_update_pid_func();
7208 ftrace_startup_all(0);
7210 mutex_unlock(&ftrace_lock);
7213 /* Greater than any max PID */
7214 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
7216 static void *fpid_start(struct seq_file *m, loff_t *pos)
7219 struct trace_pid_list *pid_list;
7220 struct trace_array *tr = m->private;
7222 mutex_lock(&ftrace_lock);
7223 rcu_read_lock_sched();
7225 pid_list = rcu_dereference_sched(tr->function_pids);
7228 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7230 return trace_pid_start(pid_list, pos);
7233 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
7235 struct trace_array *tr = m->private;
7236 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
7238 if (v == FTRACE_NO_PIDS) {
7242 return trace_pid_next(pid_list, v, pos);
7245 static void fpid_stop(struct seq_file *m, void *p)
7248 rcu_read_unlock_sched();
7249 mutex_unlock(&ftrace_lock);
7252 static int fpid_show(struct seq_file *m, void *v)
7254 if (v == FTRACE_NO_PIDS) {
7255 seq_puts(m, "no pid\n");
7259 return trace_pid_show(m, v);
7262 static const struct seq_operations ftrace_pid_sops = {
7263 .start = fpid_start,
7269 static void *fnpid_start(struct seq_file *m, loff_t *pos)
7272 struct trace_pid_list *pid_list;
7273 struct trace_array *tr = m->private;
7275 mutex_lock(&ftrace_lock);
7276 rcu_read_lock_sched();
7278 pid_list = rcu_dereference_sched(tr->function_no_pids);
7281 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7283 return trace_pid_start(pid_list, pos);
7286 static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
7288 struct trace_array *tr = m->private;
7289 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
7291 if (v == FTRACE_NO_PIDS) {
7295 return trace_pid_next(pid_list, v, pos);
7298 static const struct seq_operations ftrace_no_pid_sops = {
7299 .start = fnpid_start,
7305 static int pid_open(struct inode *inode, struct file *file, int type)
7307 const struct seq_operations *seq_ops;
7308 struct trace_array *tr = inode->i_private;
7312 ret = tracing_check_open_get_tr(tr);
7316 if ((file->f_mode & FMODE_WRITE) &&
7317 (file->f_flags & O_TRUNC))
7318 ftrace_pid_reset(tr, type);
7322 seq_ops = &ftrace_pid_sops;
7325 seq_ops = &ftrace_no_pid_sops;
7328 trace_array_put(tr);
7333 ret = seq_open(file, seq_ops);
7335 trace_array_put(tr);
7337 m = file->private_data;
7338 /* copy tr over to seq ops */
7346 ftrace_pid_open(struct inode *inode, struct file *file)
7348 return pid_open(inode, file, TRACE_PIDS);
7352 ftrace_no_pid_open(struct inode *inode, struct file *file)
7354 return pid_open(inode, file, TRACE_NO_PIDS);
7357 static void ignore_task_cpu(void *data)
7359 struct trace_array *tr = data;
7360 struct trace_pid_list *pid_list;
7361 struct trace_pid_list *no_pid_list;
7364 * This function is called by on_each_cpu() while the
7365 * event_mutex is held.
7367 pid_list = rcu_dereference_protected(tr->function_pids,
7368 mutex_is_locked(&ftrace_lock));
7369 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7370 mutex_is_locked(&ftrace_lock));
7372 if (trace_ignore_this_task(pid_list, no_pid_list, current))
7373 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7376 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7381 pid_write(struct file *filp, const char __user *ubuf,
7382 size_t cnt, loff_t *ppos, int type)
7384 struct seq_file *m = filp->private_data;
7385 struct trace_array *tr = m->private;
7386 struct trace_pid_list *filtered_pids;
7387 struct trace_pid_list *other_pids;
7388 struct trace_pid_list *pid_list;
7394 mutex_lock(&ftrace_lock);
7398 filtered_pids = rcu_dereference_protected(tr->function_pids,
7399 lockdep_is_held(&ftrace_lock));
7400 other_pids = rcu_dereference_protected(tr->function_no_pids,
7401 lockdep_is_held(&ftrace_lock));
7404 filtered_pids = rcu_dereference_protected(tr->function_no_pids,
7405 lockdep_is_held(&ftrace_lock));
7406 other_pids = rcu_dereference_protected(tr->function_pids,
7407 lockdep_is_held(&ftrace_lock));
7415 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
7421 rcu_assign_pointer(tr->function_pids, pid_list);
7424 rcu_assign_pointer(tr->function_no_pids, pid_list);
7429 if (filtered_pids) {
7431 trace_free_pid_list(filtered_pids);
7432 } else if (pid_list && !other_pids) {
7433 /* Register a probe to set whether to ignore the tracing of a task */
7434 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7438 * Ignoring of pids is done at task switch. But we have to
7439 * check for those tasks that are currently running.
7440 * Always do this in case a pid was appended or removed.
7442 on_each_cpu(ignore_task_cpu, tr, 1);
7444 ftrace_update_pid_func();
7445 ftrace_startup_all(0);
7447 mutex_unlock(&ftrace_lock);
7456 ftrace_pid_write(struct file *filp, const char __user *ubuf,
7457 size_t cnt, loff_t *ppos)
7459 return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
7463 ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
7464 size_t cnt, loff_t *ppos)
7466 return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
7470 ftrace_pid_release(struct inode *inode, struct file *file)
7472 struct trace_array *tr = inode->i_private;
7474 trace_array_put(tr);
7476 return seq_release(inode, file);
7479 static const struct file_operations ftrace_pid_fops = {
7480 .open = ftrace_pid_open,
7481 .write = ftrace_pid_write,
7483 .llseek = tracing_lseek,
7484 .release = ftrace_pid_release,
7487 static const struct file_operations ftrace_no_pid_fops = {
7488 .open = ftrace_no_pid_open,
7489 .write = ftrace_no_pid_write,
7491 .llseek = tracing_lseek,
7492 .release = ftrace_pid_release,
7495 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
7497 trace_create_file("set_ftrace_pid", 0644, d_tracer,
7498 tr, &ftrace_pid_fops);
7499 trace_create_file("set_ftrace_notrace_pid", 0644, d_tracer,
7500 tr, &ftrace_no_pid_fops);
7503 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
7504 struct dentry *d_tracer)
7506 /* Only the top level directory has the dyn_tracefs and profile */
7507 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
7509 ftrace_init_dyn_tracefs(d_tracer);
7510 ftrace_profile_tracefs(d_tracer);
7514 * ftrace_kill - kill ftrace
7516 * This function should be used by panic code. It stops ftrace
7517 * but in a not so nice way. If you need to simply kill ftrace
7518 * from a non-atomic section, use ftrace_kill.
7520 void ftrace_kill(void)
7522 ftrace_disabled = 1;
7524 ftrace_trace_function = ftrace_stub;
7528 * Test if ftrace is dead or not.
7530 int ftrace_is_dead(void)
7532 return ftrace_disabled;
7536 * register_ftrace_function - register a function for profiling
7537 * @ops - ops structure that holds the function for profiling.
7539 * Register a function to be called by all functions in the
7542 * Note: @ops->func and all the functions it calls must be labeled
7543 * with "notrace", otherwise it will go into a
7546 int register_ftrace_function(struct ftrace_ops *ops)
7550 ftrace_ops_init(ops);
7552 mutex_lock(&ftrace_lock);
7554 ret = ftrace_startup(ops, 0);
7556 mutex_unlock(&ftrace_lock);
7560 EXPORT_SYMBOL_GPL(register_ftrace_function);
7563 * unregister_ftrace_function - unregister a function for profiling.
7564 * @ops - ops structure that holds the function to unregister
7566 * Unregister a function that was added to be called by ftrace profiling.
7568 int unregister_ftrace_function(struct ftrace_ops *ops)
7572 mutex_lock(&ftrace_lock);
7573 ret = ftrace_shutdown(ops, 0);
7574 mutex_unlock(&ftrace_lock);
7578 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
7580 static bool is_permanent_ops_registered(void)
7582 struct ftrace_ops *op;
7584 do_for_each_ftrace_op(op, ftrace_ops_list) {
7585 if (op->flags & FTRACE_OPS_FL_PERMANENT)
7587 } while_for_each_ftrace_op(op);
7593 ftrace_enable_sysctl(struct ctl_table *table, int write,
7594 void *buffer, size_t *lenp, loff_t *ppos)
7598 mutex_lock(&ftrace_lock);
7600 if (unlikely(ftrace_disabled))
7603 ret = proc_dointvec(table, write, buffer, lenp, ppos);
7605 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
7608 if (ftrace_enabled) {
7610 /* we are starting ftrace again */
7611 if (rcu_dereference_protected(ftrace_ops_list,
7612 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
7613 update_ftrace_function();
7615 ftrace_startup_sysctl();
7618 if (is_permanent_ops_registered()) {
7619 ftrace_enabled = true;
7624 /* stopping ftrace calls (just send to ftrace_stub) */
7625 ftrace_trace_function = ftrace_stub;
7627 ftrace_shutdown_sysctl();
7630 last_ftrace_enabled = !!ftrace_enabled;
7632 mutex_unlock(&ftrace_lock);