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/seq_file.h>
22 #include <linux/tracefs.h>
23 #include <linux/hardirq.h>
24 #include <linux/kthread.h>
25 #include <linux/uaccess.h>
26 #include <linux/bsearch.h>
27 #include <linux/module.h>
28 #include <linux/ftrace.h>
29 #include <linux/sysctl.h>
30 #include <linux/slab.h>
31 #include <linux/ctype.h>
32 #include <linux/sort.h>
33 #include <linux/list.h>
34 #include <linux/hash.h>
35 #include <linux/rcupdate.h>
36 #include <linux/kprobes.h>
38 #include <trace/events/sched.h>
40 #include <asm/sections.h>
41 #include <asm/setup.h>
43 #include "ftrace_internal.h"
44 #include "trace_output.h"
45 #include "trace_stat.h"
47 #define FTRACE_WARN_ON(cond) \
55 #define FTRACE_WARN_ON_ONCE(cond) \
58 if (WARN_ON_ONCE(___r)) \
63 /* hash bits for specific function selection */
64 #define FTRACE_HASH_BITS 7
65 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
66 #define FTRACE_HASH_DEFAULT_BITS 10
67 #define FTRACE_HASH_MAX_BITS 12
69 #ifdef CONFIG_DYNAMIC_FTRACE
70 #define INIT_OPS_HASH(opsname) \
71 .func_hash = &opsname.local_hash, \
72 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
74 #define INIT_OPS_HASH(opsname)
78 FTRACE_MODIFY_ENABLE_FL = (1 << 0),
79 FTRACE_MODIFY_MAY_SLEEP_FL = (1 << 1),
82 struct ftrace_ops ftrace_list_end __read_mostly = {
84 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
85 INIT_OPS_HASH(ftrace_list_end)
88 /* ftrace_enabled is a method to turn ftrace on or off */
89 int ftrace_enabled __read_mostly;
90 static int last_ftrace_enabled;
92 /* Current function tracing op */
93 struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
94 /* What to set function_trace_op to */
95 static struct ftrace_ops *set_function_trace_op;
97 static bool ftrace_pids_enabled(struct ftrace_ops *ops)
99 struct trace_array *tr;
101 if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
106 return tr->function_pids != NULL;
109 static void ftrace_update_trampoline(struct ftrace_ops *ops);
112 * ftrace_disabled is set when an anomaly is discovered.
113 * ftrace_disabled is much stronger than ftrace_enabled.
115 static int ftrace_disabled __read_mostly;
117 DEFINE_MUTEX(ftrace_lock);
119 struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
120 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
121 struct ftrace_ops global_ops;
123 #if ARCH_SUPPORTS_FTRACE_OPS
124 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
125 struct ftrace_ops *op, struct pt_regs *regs);
127 /* See comment below, where ftrace_ops_list_func is defined */
128 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
129 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
132 static inline void ftrace_ops_init(struct ftrace_ops *ops)
134 #ifdef CONFIG_DYNAMIC_FTRACE
135 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
136 mutex_init(&ops->local_hash.regex_lock);
137 ops->func_hash = &ops->local_hash;
138 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
143 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
144 struct ftrace_ops *op, struct pt_regs *regs)
146 struct trace_array *tr = op->private;
148 if (tr && this_cpu_read(tr->trace_buffer.data->ftrace_ignore_pid))
151 op->saved_func(ip, parent_ip, op, regs);
154 static void ftrace_sync(struct work_struct *work)
157 * This function is just a stub to implement a hard force
158 * of synchronize_rcu(). This requires synchronizing
159 * tasks even in userspace and idle.
161 * Yes, function tracing is rude.
165 static void ftrace_sync_ipi(void *data)
167 /* Probably not needed, but do it anyway */
171 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
174 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
175 * then it needs to call the list anyway.
177 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
178 FTRACE_FORCE_LIST_FUNC)
179 return ftrace_ops_list_func;
181 return ftrace_ops_get_func(ops);
184 static void update_ftrace_function(void)
189 * Prepare the ftrace_ops that the arch callback will use.
190 * If there's only one ftrace_ops registered, the ftrace_ops_list
191 * will point to the ops we want.
193 set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
194 lockdep_is_held(&ftrace_lock));
196 /* If there's no ftrace_ops registered, just call the stub function */
197 if (set_function_trace_op == &ftrace_list_end) {
201 * If we are at the end of the list and this ops is
202 * recursion safe and not dynamic and the arch supports passing ops,
203 * then have the mcount trampoline call the function directly.
205 } else if (rcu_dereference_protected(ftrace_ops_list->next,
206 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
207 func = ftrace_ops_get_list_func(ftrace_ops_list);
210 /* Just use the default ftrace_ops */
211 set_function_trace_op = &ftrace_list_end;
212 func = ftrace_ops_list_func;
215 update_function_graph_func();
217 /* If there's no change, then do nothing more here */
218 if (ftrace_trace_function == func)
222 * If we are using the list function, it doesn't care
223 * about the function_trace_ops.
225 if (func == ftrace_ops_list_func) {
226 ftrace_trace_function = func;
228 * Don't even bother setting function_trace_ops,
229 * it would be racy to do so anyway.
234 #ifndef CONFIG_DYNAMIC_FTRACE
236 * For static tracing, we need to be a bit more careful.
237 * The function change takes affect immediately. Thus,
238 * we need to coorditate the setting of the function_trace_ops
239 * with the setting of the ftrace_trace_function.
241 * Set the function to the list ops, which will call the
242 * function we want, albeit indirectly, but it handles the
243 * ftrace_ops and doesn't depend on function_trace_op.
245 ftrace_trace_function = ftrace_ops_list_func;
247 * Make sure all CPUs see this. Yes this is slow, but static
248 * tracing is slow and nasty to have enabled.
250 schedule_on_each_cpu(ftrace_sync);
251 /* Now all cpus are using the list ops. */
252 function_trace_op = set_function_trace_op;
253 /* Make sure the function_trace_op is visible on all CPUs */
255 /* Nasty way to force a rmb on all cpus */
256 smp_call_function(ftrace_sync_ipi, NULL, 1);
257 /* OK, we are all set to update the ftrace_trace_function now! */
258 #endif /* !CONFIG_DYNAMIC_FTRACE */
260 ftrace_trace_function = func;
263 static void add_ftrace_ops(struct ftrace_ops __rcu **list,
264 struct ftrace_ops *ops)
266 rcu_assign_pointer(ops->next, *list);
269 * We are entering ops into the list but another
270 * CPU might be walking that list. We need to make sure
271 * the ops->next pointer is valid before another CPU sees
272 * the ops pointer included into the list.
274 rcu_assign_pointer(*list, ops);
277 static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
278 struct ftrace_ops *ops)
280 struct ftrace_ops **p;
283 * If we are removing the last function, then simply point
284 * to the ftrace_stub.
286 if (rcu_dereference_protected(*list,
287 lockdep_is_held(&ftrace_lock)) == ops &&
288 rcu_dereference_protected(ops->next,
289 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
290 *list = &ftrace_list_end;
294 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
305 static void ftrace_update_trampoline(struct ftrace_ops *ops);
307 int __register_ftrace_function(struct ftrace_ops *ops)
309 if (ops->flags & FTRACE_OPS_FL_DELETED)
312 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
315 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
317 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
318 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
319 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
321 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
322 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
325 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
326 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
329 if (!core_kernel_data((unsigned long)ops))
330 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
332 add_ftrace_ops(&ftrace_ops_list, ops);
334 /* Always save the function, and reset at unregistering */
335 ops->saved_func = ops->func;
337 if (ftrace_pids_enabled(ops))
338 ops->func = ftrace_pid_func;
340 ftrace_update_trampoline(ops);
343 update_ftrace_function();
348 int __unregister_ftrace_function(struct ftrace_ops *ops)
352 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
355 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
361 update_ftrace_function();
363 ops->func = ops->saved_func;
368 static void ftrace_update_pid_func(void)
370 struct ftrace_ops *op;
372 /* Only do something if we are tracing something */
373 if (ftrace_trace_function == ftrace_stub)
376 do_for_each_ftrace_op(op, ftrace_ops_list) {
377 if (op->flags & FTRACE_OPS_FL_PID) {
378 op->func = ftrace_pids_enabled(op) ?
379 ftrace_pid_func : op->saved_func;
380 ftrace_update_trampoline(op);
382 } while_for_each_ftrace_op(op);
384 update_ftrace_function();
387 #ifdef CONFIG_FUNCTION_PROFILER
388 struct ftrace_profile {
389 struct hlist_node node;
391 unsigned long counter;
392 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
393 unsigned long long time;
394 unsigned long long time_squared;
398 struct ftrace_profile_page {
399 struct ftrace_profile_page *next;
401 struct ftrace_profile records[];
404 struct ftrace_profile_stat {
406 struct hlist_head *hash;
407 struct ftrace_profile_page *pages;
408 struct ftrace_profile_page *start;
409 struct tracer_stat stat;
412 #define PROFILE_RECORDS_SIZE \
413 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
415 #define PROFILES_PER_PAGE \
416 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
418 static int ftrace_profile_enabled __read_mostly;
420 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
421 static DEFINE_MUTEX(ftrace_profile_lock);
423 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
425 #define FTRACE_PROFILE_HASH_BITS 10
426 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
429 function_stat_next(void *v, int idx)
431 struct ftrace_profile *rec = v;
432 struct ftrace_profile_page *pg;
434 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
440 if ((void *)rec >= (void *)&pg->records[pg->index]) {
444 rec = &pg->records[0];
452 static void *function_stat_start(struct tracer_stat *trace)
454 struct ftrace_profile_stat *stat =
455 container_of(trace, struct ftrace_profile_stat, stat);
457 if (!stat || !stat->start)
460 return function_stat_next(&stat->start->records[0], 0);
463 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
464 /* function graph compares on total time */
465 static int function_stat_cmp(void *p1, void *p2)
467 struct ftrace_profile *a = p1;
468 struct ftrace_profile *b = p2;
470 if (a->time < b->time)
472 if (a->time > b->time)
478 /* not function graph compares against hits */
479 static int function_stat_cmp(void *p1, void *p2)
481 struct ftrace_profile *a = p1;
482 struct ftrace_profile *b = p2;
484 if (a->counter < b->counter)
486 if (a->counter > b->counter)
493 static int function_stat_headers(struct seq_file *m)
495 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
496 seq_puts(m, " Function "
499 "--- ---- --- ---\n");
501 seq_puts(m, " Function Hit\n"
507 static int function_stat_show(struct seq_file *m, void *v)
509 struct ftrace_profile *rec = v;
510 char str[KSYM_SYMBOL_LEN];
512 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
513 static struct trace_seq s;
514 unsigned long long avg;
515 unsigned long long stddev;
517 mutex_lock(&ftrace_profile_lock);
519 /* we raced with function_profile_reset() */
520 if (unlikely(rec->counter == 0)) {
525 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
527 do_div(avg, rec->counter);
528 if (tracing_thresh && (avg < tracing_thresh))
532 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
533 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
535 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
538 /* Sample standard deviation (s^2) */
539 if (rec->counter <= 1)
543 * Apply Welford's method:
544 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
546 stddev = rec->counter * rec->time_squared -
547 rec->time * rec->time;
550 * Divide only 1000 for ns^2 -> us^2 conversion.
551 * trace_print_graph_duration will divide 1000 again.
553 do_div(stddev, rec->counter * (rec->counter - 1) * 1000);
557 trace_print_graph_duration(rec->time, &s);
558 trace_seq_puts(&s, " ");
559 trace_print_graph_duration(avg, &s);
560 trace_seq_puts(&s, " ");
561 trace_print_graph_duration(stddev, &s);
562 trace_print_seq(m, &s);
566 mutex_unlock(&ftrace_profile_lock);
571 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
573 struct ftrace_profile_page *pg;
575 pg = stat->pages = stat->start;
578 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
583 memset(stat->hash, 0,
584 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
587 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
589 struct ftrace_profile_page *pg;
594 /* If we already allocated, do nothing */
598 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
602 #ifdef CONFIG_DYNAMIC_FTRACE
603 functions = ftrace_update_tot_cnt;
606 * We do not know the number of functions that exist because
607 * dynamic tracing is what counts them. With past experience
608 * we have around 20K functions. That should be more than enough.
609 * It is highly unlikely we will execute every function in
615 pg = stat->start = stat->pages;
617 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
619 for (i = 1; i < pages; i++) {
620 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
631 unsigned long tmp = (unsigned long)pg;
643 static int ftrace_profile_init_cpu(int cpu)
645 struct ftrace_profile_stat *stat;
648 stat = &per_cpu(ftrace_profile_stats, cpu);
651 /* If the profile is already created, simply reset it */
652 ftrace_profile_reset(stat);
657 * We are profiling all functions, but usually only a few thousand
658 * functions are hit. We'll make a hash of 1024 items.
660 size = FTRACE_PROFILE_HASH_SIZE;
662 stat->hash = kcalloc(size, sizeof(struct hlist_head), GFP_KERNEL);
667 /* Preallocate the function profiling pages */
668 if (ftrace_profile_pages_init(stat) < 0) {
677 static int ftrace_profile_init(void)
682 for_each_possible_cpu(cpu) {
683 ret = ftrace_profile_init_cpu(cpu);
691 /* interrupts must be disabled */
692 static struct ftrace_profile *
693 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
695 struct ftrace_profile *rec;
696 struct hlist_head *hhd;
699 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
700 hhd = &stat->hash[key];
702 if (hlist_empty(hhd))
705 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
713 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
714 struct ftrace_profile *rec)
718 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
719 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
723 * The memory is already allocated, this simply finds a new record to use.
725 static struct ftrace_profile *
726 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
728 struct ftrace_profile *rec = NULL;
730 /* prevent recursion (from NMIs) */
731 if (atomic_inc_return(&stat->disabled) != 1)
735 * Try to find the function again since an NMI
736 * could have added it
738 rec = ftrace_find_profiled_func(stat, ip);
742 if (stat->pages->index == PROFILES_PER_PAGE) {
743 if (!stat->pages->next)
745 stat->pages = stat->pages->next;
748 rec = &stat->pages->records[stat->pages->index++];
750 ftrace_add_profile(stat, rec);
753 atomic_dec(&stat->disabled);
759 function_profile_call(unsigned long ip, unsigned long parent_ip,
760 struct ftrace_ops *ops, struct pt_regs *regs)
762 struct ftrace_profile_stat *stat;
763 struct ftrace_profile *rec;
766 if (!ftrace_profile_enabled)
769 local_irq_save(flags);
771 stat = this_cpu_ptr(&ftrace_profile_stats);
772 if (!stat->hash || !ftrace_profile_enabled)
775 rec = ftrace_find_profiled_func(stat, ip);
777 rec = ftrace_profile_alloc(stat, ip);
784 local_irq_restore(flags);
787 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
788 static bool fgraph_graph_time = true;
790 void ftrace_graph_graph_time_control(bool enable)
792 fgraph_graph_time = enable;
795 static int profile_graph_entry(struct ftrace_graph_ent *trace)
797 struct ftrace_ret_stack *ret_stack;
799 function_profile_call(trace->func, 0, NULL, NULL);
801 /* If function graph is shutting down, ret_stack can be NULL */
802 if (!current->ret_stack)
805 ret_stack = ftrace_graph_get_ret_stack(current, 0);
807 ret_stack->subtime = 0;
812 static void profile_graph_return(struct ftrace_graph_ret *trace)
814 struct ftrace_ret_stack *ret_stack;
815 struct ftrace_profile_stat *stat;
816 unsigned long long calltime;
817 struct ftrace_profile *rec;
820 local_irq_save(flags);
821 stat = this_cpu_ptr(&ftrace_profile_stats);
822 if (!stat->hash || !ftrace_profile_enabled)
825 /* If the calltime was zero'd ignore it */
826 if (!trace->calltime)
829 calltime = trace->rettime - trace->calltime;
831 if (!fgraph_graph_time) {
833 /* Append this call time to the parent time to subtract */
834 ret_stack = ftrace_graph_get_ret_stack(current, 1);
836 ret_stack->subtime += calltime;
838 ret_stack = ftrace_graph_get_ret_stack(current, 0);
839 if (ret_stack && ret_stack->subtime < calltime)
840 calltime -= ret_stack->subtime;
845 rec = ftrace_find_profiled_func(stat, trace->func);
847 rec->time += calltime;
848 rec->time_squared += calltime * calltime;
852 local_irq_restore(flags);
855 static struct fgraph_ops fprofiler_ops = {
856 .entryfunc = &profile_graph_entry,
857 .retfunc = &profile_graph_return,
860 static int register_ftrace_profiler(void)
862 return register_ftrace_graph(&fprofiler_ops);
865 static void unregister_ftrace_profiler(void)
867 unregister_ftrace_graph(&fprofiler_ops);
870 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
871 .func = function_profile_call,
872 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
873 INIT_OPS_HASH(ftrace_profile_ops)
876 static int register_ftrace_profiler(void)
878 return register_ftrace_function(&ftrace_profile_ops);
881 static void unregister_ftrace_profiler(void)
883 unregister_ftrace_function(&ftrace_profile_ops);
885 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
888 ftrace_profile_write(struct file *filp, const char __user *ubuf,
889 size_t cnt, loff_t *ppos)
894 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
900 mutex_lock(&ftrace_profile_lock);
901 if (ftrace_profile_enabled ^ val) {
903 ret = ftrace_profile_init();
909 ret = register_ftrace_profiler();
914 ftrace_profile_enabled = 1;
916 ftrace_profile_enabled = 0;
918 * unregister_ftrace_profiler calls stop_machine
919 * so this acts like an synchronize_rcu.
921 unregister_ftrace_profiler();
925 mutex_unlock(&ftrace_profile_lock);
933 ftrace_profile_read(struct file *filp, char __user *ubuf,
934 size_t cnt, loff_t *ppos)
936 char buf[64]; /* big enough to hold a number */
939 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
940 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
943 static const struct file_operations ftrace_profile_fops = {
944 .open = tracing_open_generic,
945 .read = ftrace_profile_read,
946 .write = ftrace_profile_write,
947 .llseek = default_llseek,
950 /* used to initialize the real stat files */
951 static struct tracer_stat function_stats __initdata = {
953 .stat_start = function_stat_start,
954 .stat_next = function_stat_next,
955 .stat_cmp = function_stat_cmp,
956 .stat_headers = function_stat_headers,
957 .stat_show = function_stat_show
960 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
962 struct ftrace_profile_stat *stat;
963 struct dentry *entry;
968 for_each_possible_cpu(cpu) {
969 stat = &per_cpu(ftrace_profile_stats, cpu);
971 name = kasprintf(GFP_KERNEL, "function%d", cpu);
974 * The files created are permanent, if something happens
975 * we still do not free memory.
978 "Could not allocate stat file for cpu %d\n",
982 stat->stat = function_stats;
983 stat->stat.name = name;
984 ret = register_stat_tracer(&stat->stat);
987 "Could not register function stat for cpu %d\n",
994 entry = tracefs_create_file("function_profile_enabled", 0644,
995 d_tracer, NULL, &ftrace_profile_fops);
997 pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
1000 #else /* CONFIG_FUNCTION_PROFILER */
1001 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1004 #endif /* CONFIG_FUNCTION_PROFILER */
1006 #ifdef CONFIG_DYNAMIC_FTRACE
1008 static struct ftrace_ops *removed_ops;
1011 * Set when doing a global update, like enabling all recs or disabling them.
1012 * It is not set when just updating a single ftrace_ops.
1014 static bool update_all_ops;
1016 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1017 # error Dynamic ftrace depends on MCOUNT_RECORD
1020 struct ftrace_func_entry {
1021 struct hlist_node hlist;
1025 struct ftrace_func_probe {
1026 struct ftrace_probe_ops *probe_ops;
1027 struct ftrace_ops ops;
1028 struct trace_array *tr;
1029 struct list_head list;
1035 * We make these constant because no one should touch them,
1036 * but they are used as the default "empty hash", to avoid allocating
1037 * it all the time. These are in a read only section such that if
1038 * anyone does try to modify it, it will cause an exception.
1040 static const struct hlist_head empty_buckets[1];
1041 static const struct ftrace_hash empty_hash = {
1042 .buckets = (struct hlist_head *)empty_buckets,
1044 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1046 struct ftrace_ops global_ops = {
1047 .func = ftrace_stub,
1048 .local_hash.notrace_hash = EMPTY_HASH,
1049 .local_hash.filter_hash = EMPTY_HASH,
1050 INIT_OPS_HASH(global_ops)
1051 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
1052 FTRACE_OPS_FL_INITIALIZED |
1057 * Used by the stack undwinder to know about dynamic ftrace trampolines.
1059 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
1061 struct ftrace_ops *op = NULL;
1064 * Some of the ops may be dynamically allocated,
1065 * they are freed after a synchronize_rcu().
1067 preempt_disable_notrace();
1069 do_for_each_ftrace_op(op, ftrace_ops_list) {
1071 * This is to check for dynamically allocated trampolines.
1072 * Trampolines that are in kernel text will have
1073 * core_kernel_text() return true.
1075 if (op->trampoline && op->trampoline_size)
1076 if (addr >= op->trampoline &&
1077 addr < op->trampoline + op->trampoline_size) {
1078 preempt_enable_notrace();
1081 } while_for_each_ftrace_op(op);
1082 preempt_enable_notrace();
1088 * This is used by __kernel_text_address() to return true if the
1089 * address is on a dynamically allocated trampoline that would
1090 * not return true for either core_kernel_text() or
1091 * is_module_text_address().
1093 bool is_ftrace_trampoline(unsigned long addr)
1095 return ftrace_ops_trampoline(addr) != NULL;
1098 struct ftrace_page {
1099 struct ftrace_page *next;
1100 struct dyn_ftrace *records;
1105 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1106 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1108 /* estimate from running different kernels */
1109 #define NR_TO_INIT 10000
1111 static struct ftrace_page *ftrace_pages_start;
1112 static struct ftrace_page *ftrace_pages;
1114 static __always_inline unsigned long
1115 ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1117 if (hash->size_bits > 0)
1118 return hash_long(ip, hash->size_bits);
1123 /* Only use this function if ftrace_hash_empty() has already been tested */
1124 static __always_inline struct ftrace_func_entry *
1125 __ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1128 struct ftrace_func_entry *entry;
1129 struct hlist_head *hhd;
1131 key = ftrace_hash_key(hash, ip);
1132 hhd = &hash->buckets[key];
1134 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1135 if (entry->ip == ip)
1142 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1143 * @hash: The hash to look at
1144 * @ip: The instruction pointer to test
1146 * Search a given @hash to see if a given instruction pointer (@ip)
1149 * Returns the entry that holds the @ip if found. NULL otherwise.
1151 struct ftrace_func_entry *
1152 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1154 if (ftrace_hash_empty(hash))
1157 return __ftrace_lookup_ip(hash, ip);
1160 static void __add_hash_entry(struct ftrace_hash *hash,
1161 struct ftrace_func_entry *entry)
1163 struct hlist_head *hhd;
1166 key = ftrace_hash_key(hash, entry->ip);
1167 hhd = &hash->buckets[key];
1168 hlist_add_head(&entry->hlist, hhd);
1172 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1174 struct ftrace_func_entry *entry;
1176 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1181 __add_hash_entry(hash, entry);
1187 free_hash_entry(struct ftrace_hash *hash,
1188 struct ftrace_func_entry *entry)
1190 hlist_del(&entry->hlist);
1196 remove_hash_entry(struct ftrace_hash *hash,
1197 struct ftrace_func_entry *entry)
1199 hlist_del_rcu(&entry->hlist);
1203 static void ftrace_hash_clear(struct ftrace_hash *hash)
1205 struct hlist_head *hhd;
1206 struct hlist_node *tn;
1207 struct ftrace_func_entry *entry;
1208 int size = 1 << hash->size_bits;
1214 for (i = 0; i < size; i++) {
1215 hhd = &hash->buckets[i];
1216 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1217 free_hash_entry(hash, entry);
1219 FTRACE_WARN_ON(hash->count);
1222 static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1224 list_del(&ftrace_mod->list);
1225 kfree(ftrace_mod->module);
1226 kfree(ftrace_mod->func);
1230 static void clear_ftrace_mod_list(struct list_head *head)
1232 struct ftrace_mod_load *p, *n;
1234 /* stack tracer isn't supported yet */
1238 mutex_lock(&ftrace_lock);
1239 list_for_each_entry_safe(p, n, head, list)
1241 mutex_unlock(&ftrace_lock);
1244 static void free_ftrace_hash(struct ftrace_hash *hash)
1246 if (!hash || hash == EMPTY_HASH)
1248 ftrace_hash_clear(hash);
1249 kfree(hash->buckets);
1253 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1255 struct ftrace_hash *hash;
1257 hash = container_of(rcu, struct ftrace_hash, rcu);
1258 free_ftrace_hash(hash);
1261 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1263 if (!hash || hash == EMPTY_HASH)
1265 call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
1268 void ftrace_free_filter(struct ftrace_ops *ops)
1270 ftrace_ops_init(ops);
1271 free_ftrace_hash(ops->func_hash->filter_hash);
1272 free_ftrace_hash(ops->func_hash->notrace_hash);
1275 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1277 struct ftrace_hash *hash;
1280 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1284 size = 1 << size_bits;
1285 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1287 if (!hash->buckets) {
1292 hash->size_bits = size_bits;
1298 static int ftrace_add_mod(struct trace_array *tr,
1299 const char *func, const char *module,
1302 struct ftrace_mod_load *ftrace_mod;
1303 struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1305 ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1309 ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1310 ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1311 ftrace_mod->enable = enable;
1313 if (!ftrace_mod->func || !ftrace_mod->module)
1316 list_add(&ftrace_mod->list, mod_head);
1321 free_ftrace_mod(ftrace_mod);
1326 static struct ftrace_hash *
1327 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1329 struct ftrace_func_entry *entry;
1330 struct ftrace_hash *new_hash;
1335 new_hash = alloc_ftrace_hash(size_bits);
1340 new_hash->flags = hash->flags;
1343 if (ftrace_hash_empty(hash))
1346 size = 1 << hash->size_bits;
1347 for (i = 0; i < size; i++) {
1348 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1349 ret = add_hash_entry(new_hash, entry->ip);
1355 FTRACE_WARN_ON(new_hash->count != hash->count);
1360 free_ftrace_hash(new_hash);
1365 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1367 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1369 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1370 struct ftrace_hash *new_hash);
1372 static struct ftrace_hash *
1373 __ftrace_hash_move(struct ftrace_hash *src)
1375 struct ftrace_func_entry *entry;
1376 struct hlist_node *tn;
1377 struct hlist_head *hhd;
1378 struct ftrace_hash *new_hash;
1379 int size = src->count;
1384 * If the new source is empty, just return the empty_hash.
1386 if (ftrace_hash_empty(src))
1390 * Make the hash size about 1/2 the # found
1392 for (size /= 2; size; size >>= 1)
1395 /* Don't allocate too much */
1396 if (bits > FTRACE_HASH_MAX_BITS)
1397 bits = FTRACE_HASH_MAX_BITS;
1399 new_hash = alloc_ftrace_hash(bits);
1403 new_hash->flags = src->flags;
1405 size = 1 << src->size_bits;
1406 for (i = 0; i < size; i++) {
1407 hhd = &src->buckets[i];
1408 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1409 remove_hash_entry(src, entry);
1410 __add_hash_entry(new_hash, entry);
1418 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1419 struct ftrace_hash **dst, struct ftrace_hash *src)
1421 struct ftrace_hash *new_hash;
1424 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1425 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1428 new_hash = __ftrace_hash_move(src);
1432 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1434 /* IPMODIFY should be updated only when filter_hash updating */
1435 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1437 free_ftrace_hash(new_hash);
1443 * Remove the current set, update the hash and add
1446 ftrace_hash_rec_disable_modify(ops, enable);
1448 rcu_assign_pointer(*dst, new_hash);
1450 ftrace_hash_rec_enable_modify(ops, enable);
1455 static bool hash_contains_ip(unsigned long ip,
1456 struct ftrace_ops_hash *hash)
1459 * The function record is a match if it exists in the filter
1460 * hash and not in the notrace hash. Note, an emty hash is
1461 * considered a match for the filter hash, but an empty
1462 * notrace hash is considered not in the notrace hash.
1464 return (ftrace_hash_empty(hash->filter_hash) ||
1465 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1466 (ftrace_hash_empty(hash->notrace_hash) ||
1467 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1471 * Test the hashes for this ops to see if we want to call
1472 * the ops->func or not.
1474 * It's a match if the ip is in the ops->filter_hash or
1475 * the filter_hash does not exist or is empty,
1477 * the ip is not in the ops->notrace_hash.
1479 * This needs to be called with preemption disabled as
1480 * the hashes are freed with call_rcu().
1483 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1485 struct ftrace_ops_hash hash;
1488 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1490 * There's a small race when adding ops that the ftrace handler
1491 * that wants regs, may be called without them. We can not
1492 * allow that handler to be called if regs is NULL.
1494 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1498 rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1499 rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1501 if (hash_contains_ip(ip, &hash))
1510 * This is a double for. Do not use 'break' to break out of the loop,
1511 * you must use a goto.
1513 #define do_for_each_ftrace_rec(pg, rec) \
1514 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1516 for (_____i = 0; _____i < pg->index; _____i++) { \
1517 rec = &pg->records[_____i];
1519 #define while_for_each_ftrace_rec() \
1524 static int ftrace_cmp_recs(const void *a, const void *b)
1526 const struct dyn_ftrace *key = a;
1527 const struct dyn_ftrace *rec = b;
1529 if (key->flags < rec->ip)
1531 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1537 * ftrace_location_range - return the first address of a traced location
1538 * if it touches the given ip range
1539 * @start: start of range to search.
1540 * @end: end of range to search (inclusive). @end points to the last byte
1543 * Returns rec->ip if the related ftrace location is a least partly within
1544 * the given address range. That is, the first address of the instruction
1545 * that is either a NOP or call to the function tracer. It checks the ftrace
1546 * internal tables to determine if the address belongs or not.
1548 unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1550 struct ftrace_page *pg;
1551 struct dyn_ftrace *rec;
1552 struct dyn_ftrace key;
1555 key.flags = end; /* overload flags, as it is unsigned long */
1557 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1558 if (end < pg->records[0].ip ||
1559 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1561 rec = bsearch(&key, pg->records, pg->index,
1562 sizeof(struct dyn_ftrace),
1572 * ftrace_location - return true if the ip giving is a traced location
1573 * @ip: the instruction pointer to check
1575 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1576 * That is, the instruction that is either a NOP or call to
1577 * the function tracer. It checks the ftrace internal tables to
1578 * determine if the address belongs or not.
1580 unsigned long ftrace_location(unsigned long ip)
1582 return ftrace_location_range(ip, ip);
1586 * ftrace_text_reserved - return true if range contains an ftrace location
1587 * @start: start of range to search
1588 * @end: end of range to search (inclusive). @end points to the last byte to check.
1590 * Returns 1 if @start and @end contains a ftrace location.
1591 * That is, the instruction that is either a NOP or call to
1592 * the function tracer. It checks the ftrace internal tables to
1593 * determine if the address belongs or not.
1595 int ftrace_text_reserved(const void *start, const void *end)
1599 ret = ftrace_location_range((unsigned long)start,
1600 (unsigned long)end);
1605 /* Test if ops registered to this rec needs regs */
1606 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1608 struct ftrace_ops *ops;
1609 bool keep_regs = false;
1611 for (ops = ftrace_ops_list;
1612 ops != &ftrace_list_end; ops = ops->next) {
1613 /* pass rec in as regs to have non-NULL val */
1614 if (ftrace_ops_test(ops, rec->ip, rec)) {
1615 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1625 static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1629 struct ftrace_hash *hash;
1630 struct ftrace_hash *other_hash;
1631 struct ftrace_page *pg;
1632 struct dyn_ftrace *rec;
1633 bool update = false;
1637 /* Only update if the ops has been registered */
1638 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1642 * In the filter_hash case:
1643 * If the count is zero, we update all records.
1644 * Otherwise we just update the items in the hash.
1646 * In the notrace_hash case:
1647 * We enable the update in the hash.
1648 * As disabling notrace means enabling the tracing,
1649 * and enabling notrace means disabling, the inc variable
1653 hash = ops->func_hash->filter_hash;
1654 other_hash = ops->func_hash->notrace_hash;
1655 if (ftrace_hash_empty(hash))
1659 hash = ops->func_hash->notrace_hash;
1660 other_hash = ops->func_hash->filter_hash;
1662 * If the notrace hash has no items,
1663 * then there's nothing to do.
1665 if (ftrace_hash_empty(hash))
1669 do_for_each_ftrace_rec(pg, rec) {
1670 int in_other_hash = 0;
1674 if (rec->flags & FTRACE_FL_DISABLED)
1679 * Only the filter_hash affects all records.
1680 * Update if the record is not in the notrace hash.
1682 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1685 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1686 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1689 * If filter_hash is set, we want to match all functions
1690 * that are in the hash but not in the other hash.
1692 * If filter_hash is not set, then we are decrementing.
1693 * That means we match anything that is in the hash
1694 * and also in the other_hash. That is, we need to turn
1695 * off functions in the other hash because they are disabled
1698 if (filter_hash && in_hash && !in_other_hash)
1700 else if (!filter_hash && in_hash &&
1701 (in_other_hash || ftrace_hash_empty(other_hash)))
1709 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1713 * If there's only a single callback registered to a
1714 * function, and the ops has a trampoline registered
1715 * for it, then we can call it directly.
1717 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1718 rec->flags |= FTRACE_FL_TRAMP;
1721 * If we are adding another function callback
1722 * to this function, and the previous had a
1723 * custom trampoline in use, then we need to go
1724 * back to the default trampoline.
1726 rec->flags &= ~FTRACE_FL_TRAMP;
1729 * If any ops wants regs saved for this function
1730 * then all ops will get saved regs.
1732 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1733 rec->flags |= FTRACE_FL_REGS;
1735 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1740 * If the rec had REGS enabled and the ops that is
1741 * being removed had REGS set, then see if there is
1742 * still any ops for this record that wants regs.
1743 * If not, we can stop recording them.
1745 if (ftrace_rec_count(rec) > 0 &&
1746 rec->flags & FTRACE_FL_REGS &&
1747 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1748 if (!test_rec_ops_needs_regs(rec))
1749 rec->flags &= ~FTRACE_FL_REGS;
1753 * If the rec had TRAMP enabled, then it needs to
1754 * be cleared. As TRAMP can only be enabled iff
1755 * there is only a single ops attached to it.
1756 * In otherwords, always disable it on decrementing.
1757 * In the future, we may set it if rec count is
1758 * decremented to one, and the ops that is left
1761 rec->flags &= ~FTRACE_FL_TRAMP;
1764 * flags will be cleared in ftrace_check_record()
1765 * if rec count is zero.
1770 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1771 update |= ftrace_test_record(rec, 1) != FTRACE_UPDATE_IGNORE;
1773 /* Shortcut, if we handled all records, we are done. */
1774 if (!all && count == hash->count)
1776 } while_for_each_ftrace_rec();
1781 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1784 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1787 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1790 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1793 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1794 int filter_hash, int inc)
1796 struct ftrace_ops *op;
1798 __ftrace_hash_rec_update(ops, filter_hash, inc);
1800 if (ops->func_hash != &global_ops.local_hash)
1804 * If the ops shares the global_ops hash, then we need to update
1805 * all ops that are enabled and use this hash.
1807 do_for_each_ftrace_op(op, ftrace_ops_list) {
1811 if (op->func_hash == &global_ops.local_hash)
1812 __ftrace_hash_rec_update(op, filter_hash, inc);
1813 } while_for_each_ftrace_op(op);
1816 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1819 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1822 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1825 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1829 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1830 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1831 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1832 * Note that old_hash and new_hash has below meanings
1833 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1834 * - If the hash is EMPTY_HASH, it hits nothing
1835 * - Anything else hits the recs which match the hash entries.
1837 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1838 struct ftrace_hash *old_hash,
1839 struct ftrace_hash *new_hash)
1841 struct ftrace_page *pg;
1842 struct dyn_ftrace *rec, *end = NULL;
1845 /* Only update if the ops has been registered */
1846 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1849 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1853 * Since the IPMODIFY is a very address sensitive action, we do not
1854 * allow ftrace_ops to set all functions to new hash.
1856 if (!new_hash || !old_hash)
1859 /* Update rec->flags */
1860 do_for_each_ftrace_rec(pg, rec) {
1862 if (rec->flags & FTRACE_FL_DISABLED)
1865 /* We need to update only differences of filter_hash */
1866 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1867 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1868 if (in_old == in_new)
1872 /* New entries must ensure no others are using it */
1873 if (rec->flags & FTRACE_FL_IPMODIFY)
1875 rec->flags |= FTRACE_FL_IPMODIFY;
1876 } else /* Removed entry */
1877 rec->flags &= ~FTRACE_FL_IPMODIFY;
1878 } while_for_each_ftrace_rec();
1885 /* Roll back what we did above */
1886 do_for_each_ftrace_rec(pg, rec) {
1888 if (rec->flags & FTRACE_FL_DISABLED)
1894 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1895 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1896 if (in_old == in_new)
1900 rec->flags &= ~FTRACE_FL_IPMODIFY;
1902 rec->flags |= FTRACE_FL_IPMODIFY;
1903 } while_for_each_ftrace_rec();
1909 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1911 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1913 if (ftrace_hash_empty(hash))
1916 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1919 /* Disabling always succeeds */
1920 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1922 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1924 if (ftrace_hash_empty(hash))
1927 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1930 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1931 struct ftrace_hash *new_hash)
1933 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1935 if (ftrace_hash_empty(old_hash))
1938 if (ftrace_hash_empty(new_hash))
1941 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
1944 static void print_ip_ins(const char *fmt, const unsigned char *p)
1948 printk(KERN_CONT "%s", fmt);
1950 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1951 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1954 static struct ftrace_ops *
1955 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1956 static struct ftrace_ops *
1957 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1959 enum ftrace_bug_type ftrace_bug_type;
1960 const void *ftrace_expected;
1962 static void print_bug_type(void)
1964 switch (ftrace_bug_type) {
1965 case FTRACE_BUG_UNKNOWN:
1967 case FTRACE_BUG_INIT:
1968 pr_info("Initializing ftrace call sites\n");
1970 case FTRACE_BUG_NOP:
1971 pr_info("Setting ftrace call site to NOP\n");
1973 case FTRACE_BUG_CALL:
1974 pr_info("Setting ftrace call site to call ftrace function\n");
1976 case FTRACE_BUG_UPDATE:
1977 pr_info("Updating ftrace call site to call a different ftrace function\n");
1983 * ftrace_bug - report and shutdown function tracer
1984 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1985 * @rec: The record that failed
1987 * The arch code that enables or disables the function tracing
1988 * can call ftrace_bug() when it has detected a problem in
1989 * modifying the code. @failed should be one of either:
1990 * EFAULT - if the problem happens on reading the @ip address
1991 * EINVAL - if what is read at @ip is not what was expected
1992 * EPERM - if the problem happens on writing to the @ip address
1994 void ftrace_bug(int failed, struct dyn_ftrace *rec)
1996 unsigned long ip = rec ? rec->ip : 0;
2000 FTRACE_WARN_ON_ONCE(1);
2001 pr_info("ftrace faulted on modifying ");
2005 FTRACE_WARN_ON_ONCE(1);
2006 pr_info("ftrace failed to modify ");
2008 print_ip_ins(" actual: ", (unsigned char *)ip);
2010 if (ftrace_expected) {
2011 print_ip_ins(" expected: ", ftrace_expected);
2016 FTRACE_WARN_ON_ONCE(1);
2017 pr_info("ftrace faulted on writing ");
2021 FTRACE_WARN_ON_ONCE(1);
2022 pr_info("ftrace faulted on unknown error ");
2027 struct ftrace_ops *ops = NULL;
2029 pr_info("ftrace record flags: %lx\n", rec->flags);
2030 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2031 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2032 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2033 ops = ftrace_find_tramp_ops_any(rec);
2036 pr_cont("\ttramp: %pS (%pS)",
2037 (void *)ops->trampoline,
2039 ops = ftrace_find_tramp_ops_next(rec, ops);
2042 pr_cont("\ttramp: ERROR!");
2045 ip = ftrace_get_addr_curr(rec);
2046 pr_cont("\n expected tramp: %lx\n", ip);
2050 static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
2052 unsigned long flag = 0UL;
2054 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2056 if (rec->flags & FTRACE_FL_DISABLED)
2057 return FTRACE_UPDATE_IGNORE;
2060 * If we are updating calls:
2062 * If the record has a ref count, then we need to enable it
2063 * because someone is using it.
2065 * Otherwise we make sure its disabled.
2067 * If we are disabling calls, then disable all records that
2070 if (enable && ftrace_rec_count(rec))
2071 flag = FTRACE_FL_ENABLED;
2074 * If enabling and the REGS flag does not match the REGS_EN, or
2075 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2076 * this record. Set flags to fail the compare against ENABLED.
2079 if (!(rec->flags & FTRACE_FL_REGS) !=
2080 !(rec->flags & FTRACE_FL_REGS_EN))
2081 flag |= FTRACE_FL_REGS;
2083 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2084 !(rec->flags & FTRACE_FL_TRAMP_EN))
2085 flag |= FTRACE_FL_TRAMP;
2088 /* If the state of this record hasn't changed, then do nothing */
2089 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2090 return FTRACE_UPDATE_IGNORE;
2093 /* Save off if rec is being enabled (for return value) */
2094 flag ^= rec->flags & FTRACE_FL_ENABLED;
2097 rec->flags |= FTRACE_FL_ENABLED;
2098 if (flag & FTRACE_FL_REGS) {
2099 if (rec->flags & FTRACE_FL_REGS)
2100 rec->flags |= FTRACE_FL_REGS_EN;
2102 rec->flags &= ~FTRACE_FL_REGS_EN;
2104 if (flag & FTRACE_FL_TRAMP) {
2105 if (rec->flags & FTRACE_FL_TRAMP)
2106 rec->flags |= FTRACE_FL_TRAMP_EN;
2108 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2113 * If this record is being updated from a nop, then
2114 * return UPDATE_MAKE_CALL.
2116 * return UPDATE_MODIFY_CALL to tell the caller to convert
2117 * from the save regs, to a non-save regs function or
2118 * vice versa, or from a trampoline call.
2120 if (flag & FTRACE_FL_ENABLED) {
2121 ftrace_bug_type = FTRACE_BUG_CALL;
2122 return FTRACE_UPDATE_MAKE_CALL;
2125 ftrace_bug_type = FTRACE_BUG_UPDATE;
2126 return FTRACE_UPDATE_MODIFY_CALL;
2130 /* If there's no more users, clear all flags */
2131 if (!ftrace_rec_count(rec))
2135 * Just disable the record, but keep the ops TRAMP
2136 * and REGS states. The _EN flags must be disabled though.
2138 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2142 ftrace_bug_type = FTRACE_BUG_NOP;
2143 return FTRACE_UPDATE_MAKE_NOP;
2147 * ftrace_update_record, set a record that now is tracing or not
2148 * @rec: the record to update
2149 * @enable: set to 1 if the record is tracing, zero to force disable
2151 * The records that represent all functions that can be traced need
2152 * to be updated when tracing has been enabled.
2154 int ftrace_update_record(struct dyn_ftrace *rec, int enable)
2156 return ftrace_check_record(rec, enable, 1);
2160 * ftrace_test_record, check if the record has been enabled or not
2161 * @rec: the record to test
2162 * @enable: set to 1 to check if enabled, 0 if it is disabled
2164 * The arch code may need to test if a record is already set to
2165 * tracing to determine how to modify the function code that it
2168 int ftrace_test_record(struct dyn_ftrace *rec, int enable)
2170 return ftrace_check_record(rec, enable, 0);
2173 static struct ftrace_ops *
2174 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2176 struct ftrace_ops *op;
2177 unsigned long ip = rec->ip;
2179 do_for_each_ftrace_op(op, ftrace_ops_list) {
2181 if (!op->trampoline)
2184 if (hash_contains_ip(ip, op->func_hash))
2186 } while_for_each_ftrace_op(op);
2191 static struct ftrace_ops *
2192 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2193 struct ftrace_ops *op)
2195 unsigned long ip = rec->ip;
2197 while_for_each_ftrace_op(op) {
2199 if (!op->trampoline)
2202 if (hash_contains_ip(ip, op->func_hash))
2209 static struct ftrace_ops *
2210 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2212 struct ftrace_ops *op;
2213 unsigned long ip = rec->ip;
2216 * Need to check removed ops first.
2217 * If they are being removed, and this rec has a tramp,
2218 * and this rec is in the ops list, then it would be the
2219 * one with the tramp.
2222 if (hash_contains_ip(ip, &removed_ops->old_hash))
2227 * Need to find the current trampoline for a rec.
2228 * Now, a trampoline is only attached to a rec if there
2229 * was a single 'ops' attached to it. But this can be called
2230 * when we are adding another op to the rec or removing the
2231 * current one. Thus, if the op is being added, we can
2232 * ignore it because it hasn't attached itself to the rec
2235 * If an ops is being modified (hooking to different functions)
2236 * then we don't care about the new functions that are being
2237 * added, just the old ones (that are probably being removed).
2239 * If we are adding an ops to a function that already is using
2240 * a trampoline, it needs to be removed (trampolines are only
2241 * for single ops connected), then an ops that is not being
2242 * modified also needs to be checked.
2244 do_for_each_ftrace_op(op, ftrace_ops_list) {
2246 if (!op->trampoline)
2250 * If the ops is being added, it hasn't gotten to
2251 * the point to be removed from this tree yet.
2253 if (op->flags & FTRACE_OPS_FL_ADDING)
2258 * If the ops is being modified and is in the old
2259 * hash, then it is probably being removed from this
2262 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2263 hash_contains_ip(ip, &op->old_hash))
2266 * If the ops is not being added or modified, and it's
2267 * in its normal filter hash, then this must be the one
2270 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2271 hash_contains_ip(ip, op->func_hash))
2274 } while_for_each_ftrace_op(op);
2279 static struct ftrace_ops *
2280 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2282 struct ftrace_ops *op;
2283 unsigned long ip = rec->ip;
2285 do_for_each_ftrace_op(op, ftrace_ops_list) {
2286 /* pass rec in as regs to have non-NULL val */
2287 if (hash_contains_ip(ip, op->func_hash))
2289 } while_for_each_ftrace_op(op);
2295 * ftrace_get_addr_new - Get the call address to set to
2296 * @rec: The ftrace record descriptor
2298 * If the record has the FTRACE_FL_REGS set, that means that it
2299 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2300 * is not not set, then it wants to convert to the normal callback.
2302 * Returns the address of the trampoline to set to
2304 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2306 struct ftrace_ops *ops;
2308 /* Trampolines take precedence over regs */
2309 if (rec->flags & FTRACE_FL_TRAMP) {
2310 ops = ftrace_find_tramp_ops_new(rec);
2311 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2312 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2313 (void *)rec->ip, (void *)rec->ip, rec->flags);
2314 /* Ftrace is shutting down, return anything */
2315 return (unsigned long)FTRACE_ADDR;
2317 return ops->trampoline;
2320 if (rec->flags & FTRACE_FL_REGS)
2321 return (unsigned long)FTRACE_REGS_ADDR;
2323 return (unsigned long)FTRACE_ADDR;
2327 * ftrace_get_addr_curr - Get the call address that is already there
2328 * @rec: The ftrace record descriptor
2330 * The FTRACE_FL_REGS_EN is set when the record already points to
2331 * a function that saves all the regs. Basically the '_EN' version
2332 * represents the current state of the function.
2334 * Returns the address of the trampoline that is currently being called
2336 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2338 struct ftrace_ops *ops;
2340 /* Trampolines take precedence over regs */
2341 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2342 ops = ftrace_find_tramp_ops_curr(rec);
2343 if (FTRACE_WARN_ON(!ops)) {
2344 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2345 (void *)rec->ip, (void *)rec->ip);
2346 /* Ftrace is shutting down, return anything */
2347 return (unsigned long)FTRACE_ADDR;
2349 return ops->trampoline;
2352 if (rec->flags & FTRACE_FL_REGS_EN)
2353 return (unsigned long)FTRACE_REGS_ADDR;
2355 return (unsigned long)FTRACE_ADDR;
2359 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
2361 unsigned long ftrace_old_addr;
2362 unsigned long ftrace_addr;
2365 ftrace_addr = ftrace_get_addr_new(rec);
2367 /* This needs to be done before we call ftrace_update_record */
2368 ftrace_old_addr = ftrace_get_addr_curr(rec);
2370 ret = ftrace_update_record(rec, enable);
2372 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2375 case FTRACE_UPDATE_IGNORE:
2378 case FTRACE_UPDATE_MAKE_CALL:
2379 ftrace_bug_type = FTRACE_BUG_CALL;
2380 return ftrace_make_call(rec, ftrace_addr);
2382 case FTRACE_UPDATE_MAKE_NOP:
2383 ftrace_bug_type = FTRACE_BUG_NOP;
2384 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2386 case FTRACE_UPDATE_MODIFY_CALL:
2387 ftrace_bug_type = FTRACE_BUG_UPDATE;
2388 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2391 return -1; /* unknown ftrace bug */
2394 void __weak ftrace_replace_code(int mod_flags)
2396 struct dyn_ftrace *rec;
2397 struct ftrace_page *pg;
2398 int enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2399 int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2402 if (unlikely(ftrace_disabled))
2405 do_for_each_ftrace_rec(pg, rec) {
2407 if (rec->flags & FTRACE_FL_DISABLED)
2410 failed = __ftrace_replace_code(rec, enable);
2412 ftrace_bug(failed, rec);
2413 /* Stop processing */
2418 } while_for_each_ftrace_rec();
2421 struct ftrace_rec_iter {
2422 struct ftrace_page *pg;
2427 * ftrace_rec_iter_start, start up iterating over traced functions
2429 * Returns an iterator handle that is used to iterate over all
2430 * the records that represent address locations where functions
2433 * May return NULL if no records are available.
2435 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2438 * We only use a single iterator.
2439 * Protected by the ftrace_lock mutex.
2441 static struct ftrace_rec_iter ftrace_rec_iter;
2442 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2444 iter->pg = ftrace_pages_start;
2447 /* Could have empty pages */
2448 while (iter->pg && !iter->pg->index)
2449 iter->pg = iter->pg->next;
2458 * ftrace_rec_iter_next, get the next record to process.
2459 * @iter: The handle to the iterator.
2461 * Returns the next iterator after the given iterator @iter.
2463 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2467 if (iter->index >= iter->pg->index) {
2468 iter->pg = iter->pg->next;
2471 /* Could have empty pages */
2472 while (iter->pg && !iter->pg->index)
2473 iter->pg = iter->pg->next;
2483 * ftrace_rec_iter_record, get the record at the iterator location
2484 * @iter: The current iterator location
2486 * Returns the record that the current @iter is at.
2488 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2490 return &iter->pg->records[iter->index];
2494 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
2498 if (unlikely(ftrace_disabled))
2501 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
2503 ftrace_bug_type = FTRACE_BUG_INIT;
2504 ftrace_bug(ret, rec);
2511 * archs can override this function if they must do something
2512 * before the modifying code is performed.
2514 int __weak ftrace_arch_code_modify_prepare(void)
2520 * archs can override this function if they must do something
2521 * after the modifying code is performed.
2523 int __weak ftrace_arch_code_modify_post_process(void)
2528 void ftrace_modify_all_code(int command)
2530 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2534 if (command & FTRACE_MAY_SLEEP)
2535 mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2538 * If the ftrace_caller calls a ftrace_ops func directly,
2539 * we need to make sure that it only traces functions it
2540 * expects to trace. When doing the switch of functions,
2541 * we need to update to the ftrace_ops_list_func first
2542 * before the transition between old and new calls are set,
2543 * as the ftrace_ops_list_func will check the ops hashes
2544 * to make sure the ops are having the right functions
2548 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2549 if (FTRACE_WARN_ON(err))
2553 if (command & FTRACE_UPDATE_CALLS)
2554 ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2555 else if (command & FTRACE_DISABLE_CALLS)
2556 ftrace_replace_code(mod_flags);
2558 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2559 function_trace_op = set_function_trace_op;
2561 /* If irqs are disabled, we are in stop machine */
2562 if (!irqs_disabled())
2563 smp_call_function(ftrace_sync_ipi, NULL, 1);
2564 err = ftrace_update_ftrace_func(ftrace_trace_function);
2565 if (FTRACE_WARN_ON(err))
2569 if (command & FTRACE_START_FUNC_RET)
2570 err = ftrace_enable_ftrace_graph_caller();
2571 else if (command & FTRACE_STOP_FUNC_RET)
2572 err = ftrace_disable_ftrace_graph_caller();
2573 FTRACE_WARN_ON(err);
2576 static int __ftrace_modify_code(void *data)
2578 int *command = data;
2580 ftrace_modify_all_code(*command);
2586 * ftrace_run_stop_machine, go back to the stop machine method
2587 * @command: The command to tell ftrace what to do
2589 * If an arch needs to fall back to the stop machine method, the
2590 * it can call this function.
2592 void ftrace_run_stop_machine(int command)
2594 stop_machine(__ftrace_modify_code, &command, NULL);
2598 * arch_ftrace_update_code, modify the code to trace or not trace
2599 * @command: The command that needs to be done
2601 * Archs can override this function if it does not need to
2602 * run stop_machine() to modify code.
2604 void __weak arch_ftrace_update_code(int command)
2606 ftrace_run_stop_machine(command);
2609 static void ftrace_run_update_code(int command)
2613 ret = ftrace_arch_code_modify_prepare();
2614 FTRACE_WARN_ON(ret);
2619 * By default we use stop_machine() to modify the code.
2620 * But archs can do what ever they want as long as it
2621 * is safe. The stop_machine() is the safest, but also
2622 * produces the most overhead.
2624 arch_ftrace_update_code(command);
2626 ret = ftrace_arch_code_modify_post_process();
2627 FTRACE_WARN_ON(ret);
2630 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2631 struct ftrace_ops_hash *old_hash)
2633 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2634 ops->old_hash.filter_hash = old_hash->filter_hash;
2635 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2636 ftrace_run_update_code(command);
2637 ops->old_hash.filter_hash = NULL;
2638 ops->old_hash.notrace_hash = NULL;
2639 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2642 static ftrace_func_t saved_ftrace_func;
2643 static int ftrace_start_up;
2645 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2649 static void ftrace_startup_enable(int command)
2651 if (saved_ftrace_func != ftrace_trace_function) {
2652 saved_ftrace_func = ftrace_trace_function;
2653 command |= FTRACE_UPDATE_TRACE_FUNC;
2656 if (!command || !ftrace_enabled)
2659 ftrace_run_update_code(command);
2662 static void ftrace_startup_all(int command)
2664 update_all_ops = true;
2665 ftrace_startup_enable(command);
2666 update_all_ops = false;
2669 int ftrace_startup(struct ftrace_ops *ops, int command)
2673 if (unlikely(ftrace_disabled))
2676 ret = __register_ftrace_function(ops);
2683 * Note that ftrace probes uses this to start up
2684 * and modify functions it will probe. But we still
2685 * set the ADDING flag for modification, as probes
2686 * do not have trampolines. If they add them in the
2687 * future, then the probes will need to distinguish
2688 * between adding and updating probes.
2690 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2692 ret = ftrace_hash_ipmodify_enable(ops);
2694 /* Rollback registration process */
2695 __unregister_ftrace_function(ops);
2697 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2701 if (ftrace_hash_rec_enable(ops, 1))
2702 command |= FTRACE_UPDATE_CALLS;
2704 ftrace_startup_enable(command);
2706 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2711 int ftrace_shutdown(struct ftrace_ops *ops, int command)
2715 if (unlikely(ftrace_disabled))
2718 ret = __unregister_ftrace_function(ops);
2724 * Just warn in case of unbalance, no need to kill ftrace, it's not
2725 * critical but the ftrace_call callers may be never nopped again after
2726 * further ftrace uses.
2728 WARN_ON_ONCE(ftrace_start_up < 0);
2730 /* Disabling ipmodify never fails */
2731 ftrace_hash_ipmodify_disable(ops);
2733 if (ftrace_hash_rec_disable(ops, 1))
2734 command |= FTRACE_UPDATE_CALLS;
2736 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2738 if (saved_ftrace_func != ftrace_trace_function) {
2739 saved_ftrace_func = ftrace_trace_function;
2740 command |= FTRACE_UPDATE_TRACE_FUNC;
2743 if (!command || !ftrace_enabled) {
2745 * If these are dynamic or per_cpu ops, they still
2746 * need their data freed. Since, function tracing is
2747 * not currently active, we can just free them
2748 * without synchronizing all CPUs.
2750 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2757 * If the ops uses a trampoline, then it needs to be
2758 * tested first on update.
2760 ops->flags |= FTRACE_OPS_FL_REMOVING;
2763 /* The trampoline logic checks the old hashes */
2764 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2765 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2767 ftrace_run_update_code(command);
2770 * If there's no more ops registered with ftrace, run a
2771 * sanity check to make sure all rec flags are cleared.
2773 if (rcu_dereference_protected(ftrace_ops_list,
2774 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
2775 struct ftrace_page *pg;
2776 struct dyn_ftrace *rec;
2778 do_for_each_ftrace_rec(pg, rec) {
2779 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
2780 pr_warn(" %pS flags:%lx\n",
2781 (void *)rec->ip, rec->flags);
2782 } while_for_each_ftrace_rec();
2785 ops->old_hash.filter_hash = NULL;
2786 ops->old_hash.notrace_hash = NULL;
2789 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2792 * Dynamic ops may be freed, we must make sure that all
2793 * callers are done before leaving this function.
2794 * The same goes for freeing the per_cpu data of the per_cpu
2797 if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
2799 * We need to do a hard force of sched synchronization.
2800 * This is because we use preempt_disable() to do RCU, but
2801 * the function tracers can be called where RCU is not watching
2802 * (like before user_exit()). We can not rely on the RCU
2803 * infrastructure to do the synchronization, thus we must do it
2806 schedule_on_each_cpu(ftrace_sync);
2809 * When the kernel is preeptive, tasks can be preempted
2810 * while on a ftrace trampoline. Just scheduling a task on
2811 * a CPU is not good enough to flush them. Calling
2812 * synchornize_rcu_tasks() will wait for those tasks to
2813 * execute and either schedule voluntarily or enter user space.
2815 if (IS_ENABLED(CONFIG_PREEMPT))
2816 synchronize_rcu_tasks();
2819 arch_ftrace_trampoline_free(ops);
2825 static void ftrace_startup_sysctl(void)
2829 if (unlikely(ftrace_disabled))
2832 /* Force update next time */
2833 saved_ftrace_func = NULL;
2834 /* ftrace_start_up is true if we want ftrace running */
2835 if (ftrace_start_up) {
2836 command = FTRACE_UPDATE_CALLS;
2837 if (ftrace_graph_active)
2838 command |= FTRACE_START_FUNC_RET;
2839 ftrace_startup_enable(command);
2843 static void ftrace_shutdown_sysctl(void)
2847 if (unlikely(ftrace_disabled))
2850 /* ftrace_start_up is true if ftrace is running */
2851 if (ftrace_start_up) {
2852 command = FTRACE_DISABLE_CALLS;
2853 if (ftrace_graph_active)
2854 command |= FTRACE_STOP_FUNC_RET;
2855 ftrace_run_update_code(command);
2859 static u64 ftrace_update_time;
2860 unsigned long ftrace_update_tot_cnt;
2862 static inline int ops_traces_mod(struct ftrace_ops *ops)
2865 * Filter_hash being empty will default to trace module.
2866 * But notrace hash requires a test of individual module functions.
2868 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
2869 ftrace_hash_empty(ops->func_hash->notrace_hash);
2873 * Check if the current ops references the record.
2875 * If the ops traces all functions, then it was already accounted for.
2876 * If the ops does not trace the current record function, skip it.
2877 * If the ops ignores the function via notrace filter, skip it.
2880 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2882 /* If ops isn't enabled, ignore it */
2883 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2886 /* If ops traces all then it includes this function */
2887 if (ops_traces_mod(ops))
2890 /* The function must be in the filter */
2891 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
2892 !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
2895 /* If in notrace hash, we ignore it too */
2896 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
2902 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
2904 struct ftrace_page *pg;
2905 struct dyn_ftrace *p;
2907 unsigned long update_cnt = 0;
2908 unsigned long rec_flags = 0;
2911 start = ftrace_now(raw_smp_processor_id());
2914 * When a module is loaded, this function is called to convert
2915 * the calls to mcount in its text to nops, and also to create
2916 * an entry in the ftrace data. Now, if ftrace is activated
2917 * after this call, but before the module sets its text to
2918 * read-only, the modification of enabling ftrace can fail if
2919 * the read-only is done while ftrace is converting the calls.
2920 * To prevent this, the module's records are set as disabled
2921 * and will be enabled after the call to set the module's text
2925 rec_flags |= FTRACE_FL_DISABLED;
2927 for (pg = new_pgs; pg; pg = pg->next) {
2929 for (i = 0; i < pg->index; i++) {
2931 /* If something went wrong, bail without enabling anything */
2932 if (unlikely(ftrace_disabled))
2935 p = &pg->records[i];
2936 p->flags = rec_flags;
2939 * Do the initial record conversion from mcount jump
2940 * to the NOP instructions.
2942 if (!__is_defined(CC_USING_NOP_MCOUNT) &&
2943 !ftrace_code_disable(mod, p))
2950 stop = ftrace_now(raw_smp_processor_id());
2951 ftrace_update_time = stop - start;
2952 ftrace_update_tot_cnt += update_cnt;
2957 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2962 if (WARN_ON(!count))
2965 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2968 * We want to fill as much as possible. No more than a page
2971 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2975 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2978 /* if we can't allocate this size, try something smaller */
2985 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2994 static struct ftrace_page *
2995 ftrace_allocate_pages(unsigned long num_to_init)
2997 struct ftrace_page *start_pg;
2998 struct ftrace_page *pg;
3005 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3010 * Try to allocate as much as possible in one continues
3011 * location that fills in all of the space. We want to
3012 * waste as little space as possible.
3015 cnt = ftrace_allocate_records(pg, num_to_init);
3023 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3035 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3036 free_pages((unsigned long)pg->records, order);
3037 start_pg = pg->next;
3041 pr_info("ftrace: FAILED to allocate memory for functions\n");
3045 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3047 struct ftrace_iterator {
3051 struct ftrace_page *pg;
3052 struct dyn_ftrace *func;
3053 struct ftrace_func_probe *probe;
3054 struct ftrace_func_entry *probe_entry;
3055 struct trace_parser parser;
3056 struct ftrace_hash *hash;
3057 struct ftrace_ops *ops;
3058 struct trace_array *tr;
3059 struct list_head *mod_list;
3066 t_probe_next(struct seq_file *m, loff_t *pos)
3068 struct ftrace_iterator *iter = m->private;
3069 struct trace_array *tr = iter->ops->private;
3070 struct list_head *func_probes;
3071 struct ftrace_hash *hash;
3072 struct list_head *next;
3073 struct hlist_node *hnd = NULL;
3074 struct hlist_head *hhd;
3083 func_probes = &tr->func_probes;
3084 if (list_empty(func_probes))
3088 next = func_probes->next;
3089 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3092 if (iter->probe_entry)
3093 hnd = &iter->probe_entry->hlist;
3095 hash = iter->probe->ops.func_hash->filter_hash;
3096 size = 1 << hash->size_bits;
3099 if (iter->pidx >= size) {
3100 if (iter->probe->list.next == func_probes)
3102 next = iter->probe->list.next;
3103 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3104 hash = iter->probe->ops.func_hash->filter_hash;
3105 size = 1 << hash->size_bits;
3109 hhd = &hash->buckets[iter->pidx];
3111 if (hlist_empty(hhd)) {
3127 if (WARN_ON_ONCE(!hnd))
3130 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3135 static void *t_probe_start(struct seq_file *m, loff_t *pos)
3137 struct ftrace_iterator *iter = m->private;
3141 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3144 if (iter->mod_pos > *pos)
3148 iter->probe_entry = NULL;
3150 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3151 p = t_probe_next(m, &l);
3158 /* Only set this if we have an item */
3159 iter->flags |= FTRACE_ITER_PROBE;
3165 t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3167 struct ftrace_func_entry *probe_entry;
3168 struct ftrace_probe_ops *probe_ops;
3169 struct ftrace_func_probe *probe;
3171 probe = iter->probe;
3172 probe_entry = iter->probe_entry;
3174 if (WARN_ON_ONCE(!probe || !probe_entry))
3177 probe_ops = probe->probe_ops;
3179 if (probe_ops->print)
3180 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3182 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3183 (void *)probe_ops->func);
3189 t_mod_next(struct seq_file *m, loff_t *pos)
3191 struct ftrace_iterator *iter = m->private;
3192 struct trace_array *tr = iter->tr;
3197 iter->mod_list = iter->mod_list->next;
3199 if (iter->mod_list == &tr->mod_trace ||
3200 iter->mod_list == &tr->mod_notrace) {
3201 iter->flags &= ~FTRACE_ITER_MOD;
3205 iter->mod_pos = *pos;
3210 static void *t_mod_start(struct seq_file *m, loff_t *pos)
3212 struct ftrace_iterator *iter = m->private;
3216 if (iter->func_pos > *pos)
3219 iter->mod_pos = iter->func_pos;
3221 /* probes are only available if tr is set */
3225 for (l = 0; l <= (*pos - iter->func_pos); ) {
3226 p = t_mod_next(m, &l);
3231 iter->flags &= ~FTRACE_ITER_MOD;
3232 return t_probe_start(m, pos);
3235 /* Only set this if we have an item */
3236 iter->flags |= FTRACE_ITER_MOD;
3242 t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3244 struct ftrace_mod_load *ftrace_mod;
3245 struct trace_array *tr = iter->tr;
3247 if (WARN_ON_ONCE(!iter->mod_list) ||
3248 iter->mod_list == &tr->mod_trace ||
3249 iter->mod_list == &tr->mod_notrace)
3252 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3254 if (ftrace_mod->func)
3255 seq_printf(m, "%s", ftrace_mod->func);
3259 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3265 t_func_next(struct seq_file *m, loff_t *pos)
3267 struct ftrace_iterator *iter = m->private;
3268 struct dyn_ftrace *rec = NULL;
3273 if (iter->idx >= iter->pg->index) {
3274 if (iter->pg->next) {
3275 iter->pg = iter->pg->next;
3280 rec = &iter->pg->records[iter->idx++];
3281 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3282 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3284 ((iter->flags & FTRACE_ITER_ENABLED) &&
3285 !(rec->flags & FTRACE_FL_ENABLED))) {
3295 iter->pos = iter->func_pos = *pos;
3302 t_next(struct seq_file *m, void *v, loff_t *pos)
3304 struct ftrace_iterator *iter = m->private;
3305 loff_t l = *pos; /* t_probe_start() must use original pos */
3308 if (unlikely(ftrace_disabled))
3311 if (iter->flags & FTRACE_ITER_PROBE)
3312 return t_probe_next(m, pos);
3314 if (iter->flags & FTRACE_ITER_MOD)
3315 return t_mod_next(m, pos);
3317 if (iter->flags & FTRACE_ITER_PRINTALL) {
3318 /* next must increment pos, and t_probe_start does not */
3320 return t_mod_start(m, &l);
3323 ret = t_func_next(m, pos);
3326 return t_mod_start(m, &l);
3331 static void reset_iter_read(struct ftrace_iterator *iter)
3335 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3338 static void *t_start(struct seq_file *m, loff_t *pos)
3340 struct ftrace_iterator *iter = m->private;
3344 mutex_lock(&ftrace_lock);
3346 if (unlikely(ftrace_disabled))
3350 * If an lseek was done, then reset and start from beginning.
3352 if (*pos < iter->pos)
3353 reset_iter_read(iter);
3356 * For set_ftrace_filter reading, if we have the filter
3357 * off, we can short cut and just print out that all
3358 * functions are enabled.
3360 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3361 ftrace_hash_empty(iter->hash)) {
3362 iter->func_pos = 1; /* Account for the message */
3364 return t_mod_start(m, pos);
3365 iter->flags |= FTRACE_ITER_PRINTALL;
3366 /* reset in case of seek/pread */
3367 iter->flags &= ~FTRACE_ITER_PROBE;
3371 if (iter->flags & FTRACE_ITER_MOD)
3372 return t_mod_start(m, pos);
3375 * Unfortunately, we need to restart at ftrace_pages_start
3376 * every time we let go of the ftrace_mutex. This is because
3377 * those pointers can change without the lock.
3379 iter->pg = ftrace_pages_start;
3381 for (l = 0; l <= *pos; ) {
3382 p = t_func_next(m, &l);
3388 return t_mod_start(m, pos);
3393 static void t_stop(struct seq_file *m, void *p)
3395 mutex_unlock(&ftrace_lock);
3399 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3404 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3405 struct dyn_ftrace *rec)
3409 ptr = arch_ftrace_trampoline_func(ops, rec);
3411 seq_printf(m, " ->%pS", ptr);
3414 static int t_show(struct seq_file *m, void *v)
3416 struct ftrace_iterator *iter = m->private;
3417 struct dyn_ftrace *rec;
3419 if (iter->flags & FTRACE_ITER_PROBE)
3420 return t_probe_show(m, iter);
3422 if (iter->flags & FTRACE_ITER_MOD)
3423 return t_mod_show(m, iter);
3425 if (iter->flags & FTRACE_ITER_PRINTALL) {
3426 if (iter->flags & FTRACE_ITER_NOTRACE)
3427 seq_puts(m, "#### no functions disabled ####\n");
3429 seq_puts(m, "#### all functions enabled ####\n");
3438 seq_printf(m, "%ps", (void *)rec->ip);
3439 if (iter->flags & FTRACE_ITER_ENABLED) {
3440 struct ftrace_ops *ops;
3442 seq_printf(m, " (%ld)%s%s",
3443 ftrace_rec_count(rec),
3444 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3445 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ");
3446 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3447 ops = ftrace_find_tramp_ops_any(rec);
3450 seq_printf(m, "\ttramp: %pS (%pS)",
3451 (void *)ops->trampoline,
3453 add_trampoline_func(m, ops, rec);
3454 ops = ftrace_find_tramp_ops_next(rec, ops);
3457 seq_puts(m, "\ttramp: ERROR!");
3459 add_trampoline_func(m, NULL, rec);
3468 static const struct seq_operations show_ftrace_seq_ops = {
3476 ftrace_avail_open(struct inode *inode, struct file *file)
3478 struct ftrace_iterator *iter;
3480 if (unlikely(ftrace_disabled))
3483 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3487 iter->pg = ftrace_pages_start;
3488 iter->ops = &global_ops;
3494 ftrace_enabled_open(struct inode *inode, struct file *file)
3496 struct ftrace_iterator *iter;
3498 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3502 iter->pg = ftrace_pages_start;
3503 iter->flags = FTRACE_ITER_ENABLED;
3504 iter->ops = &global_ops;
3510 * ftrace_regex_open - initialize function tracer filter files
3511 * @ops: The ftrace_ops that hold the hash filters
3512 * @flag: The type of filter to process
3513 * @inode: The inode, usually passed in to your open routine
3514 * @file: The file, usually passed in to your open routine
3516 * ftrace_regex_open() initializes the filter files for the
3517 * @ops. Depending on @flag it may process the filter hash or
3518 * the notrace hash of @ops. With this called from the open
3519 * routine, you can use ftrace_filter_write() for the write
3520 * routine if @flag has FTRACE_ITER_FILTER set, or
3521 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3522 * tracing_lseek() should be used as the lseek routine, and
3523 * release must call ftrace_regex_release().
3526 ftrace_regex_open(struct ftrace_ops *ops, int flag,
3527 struct inode *inode, struct file *file)
3529 struct ftrace_iterator *iter;
3530 struct ftrace_hash *hash;
3531 struct list_head *mod_head;
3532 struct trace_array *tr = ops->private;
3535 ftrace_ops_init(ops);
3537 if (unlikely(ftrace_disabled))
3540 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3544 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
3553 mutex_lock(&ops->func_hash->regex_lock);
3555 if (flag & FTRACE_ITER_NOTRACE) {
3556 hash = ops->func_hash->notrace_hash;
3557 mod_head = tr ? &tr->mod_notrace : NULL;
3559 hash = ops->func_hash->filter_hash;
3560 mod_head = tr ? &tr->mod_trace : NULL;
3563 iter->mod_list = mod_head;
3565 if (file->f_mode & FMODE_WRITE) {
3566 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3568 if (file->f_flags & O_TRUNC) {
3569 iter->hash = alloc_ftrace_hash(size_bits);
3570 clear_ftrace_mod_list(mod_head);
3572 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3576 trace_parser_put(&iter->parser);
3584 if (file->f_mode & FMODE_READ) {
3585 iter->pg = ftrace_pages_start;
3587 ret = seq_open(file, &show_ftrace_seq_ops);
3589 struct seq_file *m = file->private_data;
3593 free_ftrace_hash(iter->hash);
3594 trace_parser_put(&iter->parser);
3598 file->private_data = iter;
3601 mutex_unlock(&ops->func_hash->regex_lock);
3607 ftrace_filter_open(struct inode *inode, struct file *file)
3609 struct ftrace_ops *ops = inode->i_private;
3611 return ftrace_regex_open(ops,
3612 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3617 ftrace_notrace_open(struct inode *inode, struct file *file)
3619 struct ftrace_ops *ops = inode->i_private;
3621 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3625 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3626 struct ftrace_glob {
3633 * If symbols in an architecture don't correspond exactly to the user-visible
3634 * name of what they represent, it is possible to define this function to
3635 * perform the necessary adjustments.
3637 char * __weak arch_ftrace_match_adjust(char *str, const char *search)
3642 static int ftrace_match(char *str, struct ftrace_glob *g)
3647 str = arch_ftrace_match_adjust(str, g->search);
3651 if (strcmp(str, g->search) == 0)
3654 case MATCH_FRONT_ONLY:
3655 if (strncmp(str, g->search, g->len) == 0)
3658 case MATCH_MIDDLE_ONLY:
3659 if (strstr(str, g->search))
3662 case MATCH_END_ONLY:
3664 if (slen >= g->len &&
3665 memcmp(str + slen - g->len, g->search, g->len) == 0)
3669 if (glob_match(g->search, str))
3678 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3680 struct ftrace_func_entry *entry;
3683 entry = ftrace_lookup_ip(hash, rec->ip);
3685 /* Do nothing if it doesn't exist */
3689 free_hash_entry(hash, entry);
3691 /* Do nothing if it exists */
3695 ret = add_hash_entry(hash, rec->ip);
3701 add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
3704 long index = simple_strtoul(func_g->search, NULL, 0);
3705 struct ftrace_page *pg;
3706 struct dyn_ftrace *rec;
3708 /* The index starts at 1 */
3712 do_for_each_ftrace_rec(pg, rec) {
3713 if (pg->index <= index) {
3715 /* this is a double loop, break goes to the next page */
3718 rec = &pg->records[index];
3719 enter_record(hash, rec, clear_filter);
3721 } while_for_each_ftrace_rec();
3726 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3727 struct ftrace_glob *mod_g, int exclude_mod)
3729 char str[KSYM_SYMBOL_LEN];
3732 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3735 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3737 /* blank module name to match all modules */
3739 /* blank module globbing: modname xor exclude_mod */
3740 if (!exclude_mod != !modname)
3746 * exclude_mod is set to trace everything but the given
3747 * module. If it is set and the module matches, then
3748 * return 0. If it is not set, and the module doesn't match
3749 * also return 0. Otherwise, check the function to see if
3752 if (!mod_matches == !exclude_mod)
3755 /* blank search means to match all funcs in the mod */
3760 return ftrace_match(str, func_g);
3764 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
3766 struct ftrace_page *pg;
3767 struct dyn_ftrace *rec;
3768 struct ftrace_glob func_g = { .type = MATCH_FULL };
3769 struct ftrace_glob mod_g = { .type = MATCH_FULL };
3770 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
3771 int exclude_mod = 0;
3774 int clear_filter = 0;
3777 func_g.type = filter_parse_regex(func, len, &func_g.search,
3779 func_g.len = strlen(func_g.search);
3783 mod_g.type = filter_parse_regex(mod, strlen(mod),
3784 &mod_g.search, &exclude_mod);
3785 mod_g.len = strlen(mod_g.search);
3788 mutex_lock(&ftrace_lock);
3790 if (unlikely(ftrace_disabled))
3793 if (func_g.type == MATCH_INDEX) {
3794 found = add_rec_by_index(hash, &func_g, clear_filter);
3798 do_for_each_ftrace_rec(pg, rec) {
3800 if (rec->flags & FTRACE_FL_DISABLED)
3803 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
3804 ret = enter_record(hash, rec, clear_filter);
3811 } while_for_each_ftrace_rec();
3813 mutex_unlock(&ftrace_lock);
3819 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
3821 return match_records(hash, buff, len, NULL);
3824 static void ftrace_ops_update_code(struct ftrace_ops *ops,
3825 struct ftrace_ops_hash *old_hash)
3827 struct ftrace_ops *op;
3829 if (!ftrace_enabled)
3832 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
3833 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
3838 * If this is the shared global_ops filter, then we need to
3839 * check if there is another ops that shares it, is enabled.
3840 * If so, we still need to run the modify code.
3842 if (ops->func_hash != &global_ops.local_hash)
3845 do_for_each_ftrace_op(op, ftrace_ops_list) {
3846 if (op->func_hash == &global_ops.local_hash &&
3847 op->flags & FTRACE_OPS_FL_ENABLED) {
3848 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
3849 /* Only need to do this once */
3852 } while_for_each_ftrace_op(op);
3855 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
3856 struct ftrace_hash **orig_hash,
3857 struct ftrace_hash *hash,
3860 struct ftrace_ops_hash old_hash_ops;
3861 struct ftrace_hash *old_hash;
3864 old_hash = *orig_hash;
3865 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
3866 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
3867 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3869 ftrace_ops_update_code(ops, &old_hash_ops);
3870 free_ftrace_hash_rcu(old_hash);
3875 static bool module_exists(const char *module)
3877 /* All modules have the symbol __this_module */
3878 static const char this_mod[] = "__this_module";
3879 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
3883 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
3885 if (n > sizeof(modname) - 1)
3888 val = module_kallsyms_lookup_name(modname);
3892 static int cache_mod(struct trace_array *tr,
3893 const char *func, char *module, int enable)
3895 struct ftrace_mod_load *ftrace_mod, *n;
3896 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
3899 mutex_lock(&ftrace_lock);
3901 /* We do not cache inverse filters */
3902 if (func[0] == '!') {
3906 /* Look to remove this hash */
3907 list_for_each_entry_safe(ftrace_mod, n, head, list) {
3908 if (strcmp(ftrace_mod->module, module) != 0)
3911 /* no func matches all */
3912 if (strcmp(func, "*") == 0 ||
3913 (ftrace_mod->func &&
3914 strcmp(ftrace_mod->func, func) == 0)) {
3916 free_ftrace_mod(ftrace_mod);
3924 /* We only care about modules that have not been loaded yet */
3925 if (module_exists(module))
3928 /* Save this string off, and execute it when the module is loaded */
3929 ret = ftrace_add_mod(tr, func, module, enable);
3931 mutex_unlock(&ftrace_lock);
3937 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
3938 int reset, int enable);
3940 #ifdef CONFIG_MODULES
3941 static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
3942 char *mod, bool enable)
3944 struct ftrace_mod_load *ftrace_mod, *n;
3945 struct ftrace_hash **orig_hash, *new_hash;
3946 LIST_HEAD(process_mods);
3950 mutex_lock(&ops->func_hash->regex_lock);
3953 orig_hash = &ops->func_hash->filter_hash;
3955 orig_hash = &ops->func_hash->notrace_hash;
3957 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
3960 goto out; /* warn? */
3962 mutex_lock(&ftrace_lock);
3964 list_for_each_entry_safe(ftrace_mod, n, head, list) {
3966 if (strcmp(ftrace_mod->module, mod) != 0)
3969 if (ftrace_mod->func)
3970 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
3972 func = kstrdup("*", GFP_KERNEL);
3974 if (!func) /* warn? */
3977 list_del(&ftrace_mod->list);
3978 list_add(&ftrace_mod->list, &process_mods);
3980 /* Use the newly allocated func, as it may be "*" */
3981 kfree(ftrace_mod->func);
3982 ftrace_mod->func = func;
3985 mutex_unlock(&ftrace_lock);
3987 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
3989 func = ftrace_mod->func;
3991 /* Grabs ftrace_lock, which is why we have this extra step */
3992 match_records(new_hash, func, strlen(func), mod);
3993 free_ftrace_mod(ftrace_mod);
3996 if (enable && list_empty(head))
3997 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
3999 mutex_lock(&ftrace_lock);
4001 ret = ftrace_hash_move_and_update_ops(ops, orig_hash,
4003 mutex_unlock(&ftrace_lock);
4006 mutex_unlock(&ops->func_hash->regex_lock);
4008 free_ftrace_hash(new_hash);
4011 static void process_cached_mods(const char *mod_name)
4013 struct trace_array *tr;
4016 mod = kstrdup(mod_name, GFP_KERNEL);
4020 mutex_lock(&trace_types_lock);
4021 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4022 if (!list_empty(&tr->mod_trace))
4023 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4024 if (!list_empty(&tr->mod_notrace))
4025 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4027 mutex_unlock(&trace_types_lock);
4034 * We register the module command as a template to show others how
4035 * to register the a command as well.
4039 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4040 char *func_orig, char *cmd, char *module, int enable)
4045 /* match_records() modifies func, and we need the original */
4046 func = kstrdup(func_orig, GFP_KERNEL);
4051 * cmd == 'mod' because we only registered this func
4052 * for the 'mod' ftrace_func_command.
4053 * But if you register one func with multiple commands,
4054 * you can tell which command was used by the cmd
4057 ret = match_records(hash, func, strlen(func), module);
4061 return cache_mod(tr, func_orig, module, enable);
4067 static struct ftrace_func_command ftrace_mod_cmd = {
4069 .func = ftrace_mod_callback,
4072 static int __init ftrace_mod_cmd_init(void)
4074 return register_ftrace_command(&ftrace_mod_cmd);
4076 core_initcall(ftrace_mod_cmd_init);
4078 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4079 struct ftrace_ops *op, struct pt_regs *pt_regs)
4081 struct ftrace_probe_ops *probe_ops;
4082 struct ftrace_func_probe *probe;
4084 probe = container_of(op, struct ftrace_func_probe, ops);
4085 probe_ops = probe->probe_ops;
4088 * Disable preemption for these calls to prevent a RCU grace
4089 * period. This syncs the hash iteration and freeing of items
4090 * on the hash. rcu_read_lock is too dangerous here.
4092 preempt_disable_notrace();
4093 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4094 preempt_enable_notrace();
4097 struct ftrace_func_map {
4098 struct ftrace_func_entry entry;
4102 struct ftrace_func_mapper {
4103 struct ftrace_hash hash;
4107 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4109 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4111 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4113 struct ftrace_hash *hash;
4116 * The mapper is simply a ftrace_hash, but since the entries
4117 * in the hash are not ftrace_func_entry type, we define it
4118 * as a separate structure.
4120 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4121 return (struct ftrace_func_mapper *)hash;
4125 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4126 * @mapper: The mapper that has the ip maps
4127 * @ip: the instruction pointer to find the data for
4129 * Returns the data mapped to @ip if found otherwise NULL. The return
4130 * is actually the address of the mapper data pointer. The address is
4131 * returned for use cases where the data is no bigger than a long, and
4132 * the user can use the data pointer as its data instead of having to
4133 * allocate more memory for the reference.
4135 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4138 struct ftrace_func_entry *entry;
4139 struct ftrace_func_map *map;
4141 entry = ftrace_lookup_ip(&mapper->hash, ip);
4145 map = (struct ftrace_func_map *)entry;
4150 * ftrace_func_mapper_add_ip - Map some data to an ip
4151 * @mapper: The mapper that has the ip maps
4152 * @ip: The instruction pointer address to map @data to
4153 * @data: The data to map to @ip
4155 * Returns 0 on succes otherwise an error.
4157 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4158 unsigned long ip, void *data)
4160 struct ftrace_func_entry *entry;
4161 struct ftrace_func_map *map;
4163 entry = ftrace_lookup_ip(&mapper->hash, ip);
4167 map = kmalloc(sizeof(*map), GFP_KERNEL);
4174 __add_hash_entry(&mapper->hash, &map->entry);
4180 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4181 * @mapper: The mapper that has the ip maps
4182 * @ip: The instruction pointer address to remove the data from
4184 * Returns the data if it is found, otherwise NULL.
4185 * Note, if the data pointer is used as the data itself, (see
4186 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4187 * if the data pointer was set to zero.
4189 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4192 struct ftrace_func_entry *entry;
4193 struct ftrace_func_map *map;
4196 entry = ftrace_lookup_ip(&mapper->hash, ip);
4200 map = (struct ftrace_func_map *)entry;
4203 remove_hash_entry(&mapper->hash, entry);
4210 * free_ftrace_func_mapper - free a mapping of ips and data
4211 * @mapper: The mapper that has the ip maps
4212 * @free_func: A function to be called on each data item.
4214 * This is used to free the function mapper. The @free_func is optional
4215 * and can be used if the data needs to be freed as well.
4217 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4218 ftrace_mapper_func free_func)
4220 struct ftrace_func_entry *entry;
4221 struct ftrace_func_map *map;
4222 struct hlist_head *hhd;
4228 if (free_func && mapper->hash.count) {
4229 size = 1 << mapper->hash.size_bits;
4230 for (i = 0; i < size; i++) {
4231 hhd = &mapper->hash.buckets[i];
4232 hlist_for_each_entry(entry, hhd, hlist) {
4233 map = (struct ftrace_func_map *)entry;
4238 free_ftrace_hash(&mapper->hash);
4241 static void release_probe(struct ftrace_func_probe *probe)
4243 struct ftrace_probe_ops *probe_ops;
4245 mutex_lock(&ftrace_lock);
4247 WARN_ON(probe->ref <= 0);
4249 /* Subtract the ref that was used to protect this instance */
4253 probe_ops = probe->probe_ops;
4255 * Sending zero as ip tells probe_ops to free
4256 * the probe->data itself
4258 if (probe_ops->free)
4259 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4260 list_del(&probe->list);
4263 mutex_unlock(&ftrace_lock);
4266 static void acquire_probe_locked(struct ftrace_func_probe *probe)
4269 * Add one ref to keep it from being freed when releasing the
4270 * ftrace_lock mutex.
4276 register_ftrace_function_probe(char *glob, struct trace_array *tr,
4277 struct ftrace_probe_ops *probe_ops,
4280 struct ftrace_func_entry *entry;
4281 struct ftrace_func_probe *probe;
4282 struct ftrace_hash **orig_hash;
4283 struct ftrace_hash *old_hash;
4284 struct ftrace_hash *hash;
4293 /* We do not support '!' for function probes */
4294 if (WARN_ON(glob[0] == '!'))
4298 mutex_lock(&ftrace_lock);
4299 /* Check if the probe_ops is already registered */
4300 list_for_each_entry(probe, &tr->func_probes, list) {
4301 if (probe->probe_ops == probe_ops)
4304 if (&probe->list == &tr->func_probes) {
4305 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4307 mutex_unlock(&ftrace_lock);
4310 probe->probe_ops = probe_ops;
4311 probe->ops.func = function_trace_probe_call;
4313 ftrace_ops_init(&probe->ops);
4314 list_add(&probe->list, &tr->func_probes);
4317 acquire_probe_locked(probe);
4319 mutex_unlock(&ftrace_lock);
4321 mutex_lock(&probe->ops.func_hash->regex_lock);
4323 orig_hash = &probe->ops.func_hash->filter_hash;
4324 old_hash = *orig_hash;
4325 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4327 ret = ftrace_match_records(hash, glob, strlen(glob));
4329 /* Nothing found? */
4336 size = 1 << hash->size_bits;
4337 for (i = 0; i < size; i++) {
4338 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4339 if (ftrace_lookup_ip(old_hash, entry->ip))
4342 * The caller might want to do something special
4343 * for each function we find. We call the callback
4344 * to give the caller an opportunity to do so.
4346 if (probe_ops->init) {
4347 ret = probe_ops->init(probe_ops, tr,
4351 if (probe_ops->free && count)
4352 probe_ops->free(probe_ops, tr,
4362 mutex_lock(&ftrace_lock);
4365 /* Nothing was added? */
4370 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4375 /* One ref for each new function traced */
4376 probe->ref += count;
4378 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4379 ret = ftrace_startup(&probe->ops, 0);
4382 mutex_unlock(&ftrace_lock);
4387 mutex_unlock(&probe->ops.func_hash->regex_lock);
4388 free_ftrace_hash(hash);
4390 release_probe(probe);
4395 if (!probe_ops->free || !count)
4398 /* Failed to do the move, need to call the free functions */
4399 for (i = 0; i < size; i++) {
4400 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4401 if (ftrace_lookup_ip(old_hash, entry->ip))
4403 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4410 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4411 struct ftrace_probe_ops *probe_ops)
4413 struct ftrace_ops_hash old_hash_ops;
4414 struct ftrace_func_entry *entry;
4415 struct ftrace_func_probe *probe;
4416 struct ftrace_glob func_g;
4417 struct ftrace_hash **orig_hash;
4418 struct ftrace_hash *old_hash;
4419 struct ftrace_hash *hash = NULL;
4420 struct hlist_node *tmp;
4421 struct hlist_head hhd;
4422 char str[KSYM_SYMBOL_LEN];
4424 int i, ret = -ENODEV;
4427 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4428 func_g.search = NULL;
4432 func_g.type = filter_parse_regex(glob, strlen(glob),
4433 &func_g.search, ¬);
4434 func_g.len = strlen(func_g.search);
4436 /* we do not support '!' for function probes */
4441 mutex_lock(&ftrace_lock);
4442 /* Check if the probe_ops is already registered */
4443 list_for_each_entry(probe, &tr->func_probes, list) {
4444 if (probe->probe_ops == probe_ops)
4447 if (&probe->list == &tr->func_probes)
4448 goto err_unlock_ftrace;
4451 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4452 goto err_unlock_ftrace;
4454 acquire_probe_locked(probe);
4456 mutex_unlock(&ftrace_lock);
4458 mutex_lock(&probe->ops.func_hash->regex_lock);
4460 orig_hash = &probe->ops.func_hash->filter_hash;
4461 old_hash = *orig_hash;
4463 if (ftrace_hash_empty(old_hash))
4466 old_hash_ops.filter_hash = old_hash;
4467 /* Probes only have filters */
4468 old_hash_ops.notrace_hash = NULL;
4471 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4475 INIT_HLIST_HEAD(&hhd);
4477 size = 1 << hash->size_bits;
4478 for (i = 0; i < size; i++) {
4479 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4481 if (func_g.search) {
4482 kallsyms_lookup(entry->ip, NULL, NULL,
4484 if (!ftrace_match(str, &func_g))
4488 remove_hash_entry(hash, entry);
4489 hlist_add_head(&entry->hlist, &hhd);
4493 /* Nothing found? */
4499 mutex_lock(&ftrace_lock);
4501 WARN_ON(probe->ref < count);
4503 probe->ref -= count;
4505 if (ftrace_hash_empty(hash))
4506 ftrace_shutdown(&probe->ops, 0);
4508 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4511 /* still need to update the function call sites */
4512 if (ftrace_enabled && !ftrace_hash_empty(hash))
4513 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4517 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4518 hlist_del(&entry->hlist);
4519 if (probe_ops->free)
4520 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4523 mutex_unlock(&ftrace_lock);
4526 mutex_unlock(&probe->ops.func_hash->regex_lock);
4527 free_ftrace_hash(hash);
4529 release_probe(probe);
4534 mutex_unlock(&ftrace_lock);
4538 void clear_ftrace_function_probes(struct trace_array *tr)
4540 struct ftrace_func_probe *probe, *n;
4542 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4543 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
4546 static LIST_HEAD(ftrace_commands);
4547 static DEFINE_MUTEX(ftrace_cmd_mutex);
4550 * Currently we only register ftrace commands from __init, so mark this
4553 __init int register_ftrace_command(struct ftrace_func_command *cmd)
4555 struct ftrace_func_command *p;
4558 mutex_lock(&ftrace_cmd_mutex);
4559 list_for_each_entry(p, &ftrace_commands, list) {
4560 if (strcmp(cmd->name, p->name) == 0) {
4565 list_add(&cmd->list, &ftrace_commands);
4567 mutex_unlock(&ftrace_cmd_mutex);
4573 * Currently we only unregister ftrace commands from __init, so mark
4576 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4578 struct ftrace_func_command *p, *n;
4581 mutex_lock(&ftrace_cmd_mutex);
4582 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4583 if (strcmp(cmd->name, p->name) == 0) {
4585 list_del_init(&p->list);
4590 mutex_unlock(&ftrace_cmd_mutex);
4595 static int ftrace_process_regex(struct ftrace_iterator *iter,
4596 char *buff, int len, int enable)
4598 struct ftrace_hash *hash = iter->hash;
4599 struct trace_array *tr = iter->ops->private;
4600 char *func, *command, *next = buff;
4601 struct ftrace_func_command *p;
4604 func = strsep(&next, ":");
4607 ret = ftrace_match_records(hash, func, len);
4617 command = strsep(&next, ":");
4619 mutex_lock(&ftrace_cmd_mutex);
4620 list_for_each_entry(p, &ftrace_commands, list) {
4621 if (strcmp(p->name, command) == 0) {
4622 ret = p->func(tr, hash, func, command, next, enable);
4627 mutex_unlock(&ftrace_cmd_mutex);
4633 ftrace_regex_write(struct file *file, const char __user *ubuf,
4634 size_t cnt, loff_t *ppos, int enable)
4636 struct ftrace_iterator *iter;
4637 struct trace_parser *parser;
4643 if (file->f_mode & FMODE_READ) {
4644 struct seq_file *m = file->private_data;
4647 iter = file->private_data;
4649 if (unlikely(ftrace_disabled))
4652 /* iter->hash is a local copy, so we don't need regex_lock */
4654 parser = &iter->parser;
4655 read = trace_get_user(parser, ubuf, cnt, ppos);
4657 if (read >= 0 && trace_parser_loaded(parser) &&
4658 !trace_parser_cont(parser)) {
4659 ret = ftrace_process_regex(iter, parser->buffer,
4660 parser->idx, enable);
4661 trace_parser_clear(parser);
4672 ftrace_filter_write(struct file *file, const char __user *ubuf,
4673 size_t cnt, loff_t *ppos)
4675 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4679 ftrace_notrace_write(struct file *file, const char __user *ubuf,
4680 size_t cnt, loff_t *ppos)
4682 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4686 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4688 struct ftrace_func_entry *entry;
4690 if (!ftrace_location(ip))
4694 entry = ftrace_lookup_ip(hash, ip);
4697 free_hash_entry(hash, entry);
4701 return add_hash_entry(hash, ip);
4705 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4706 unsigned long ip, int remove, int reset, int enable)
4708 struct ftrace_hash **orig_hash;
4709 struct ftrace_hash *hash;
4712 if (unlikely(ftrace_disabled))
4715 mutex_lock(&ops->func_hash->regex_lock);
4718 orig_hash = &ops->func_hash->filter_hash;
4720 orig_hash = &ops->func_hash->notrace_hash;
4723 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4725 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4729 goto out_regex_unlock;
4732 if (buf && !ftrace_match_records(hash, buf, len)) {
4734 goto out_regex_unlock;
4737 ret = ftrace_match_addr(hash, ip, remove);
4739 goto out_regex_unlock;
4742 mutex_lock(&ftrace_lock);
4743 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
4744 mutex_unlock(&ftrace_lock);
4747 mutex_unlock(&ops->func_hash->regex_lock);
4749 free_ftrace_hash(hash);
4754 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
4755 int reset, int enable)
4757 return ftrace_set_hash(ops, NULL, 0, ip, remove, reset, enable);
4761 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
4762 * @ops - the ops to set the filter with
4763 * @ip - the address to add to or remove from the filter.
4764 * @remove - non zero to remove the ip from the filter
4765 * @reset - non zero to reset all filters before applying this filter.
4767 * Filters denote which functions should be enabled when tracing is enabled
4768 * If @ip is NULL, it failes to update filter.
4770 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
4771 int remove, int reset)
4773 ftrace_ops_init(ops);
4774 return ftrace_set_addr(ops, ip, remove, reset, 1);
4776 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
4779 * ftrace_ops_set_global_filter - setup ops to use global filters
4780 * @ops - the ops which will use the global filters
4782 * ftrace users who need global function trace filtering should call this.
4783 * It can set the global filter only if ops were not initialized before.
4785 void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
4787 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
4790 ftrace_ops_init(ops);
4791 ops->func_hash = &global_ops.local_hash;
4793 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
4796 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4797 int reset, int enable)
4799 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
4803 * ftrace_set_filter - set a function to filter on in ftrace
4804 * @ops - the ops to set the filter with
4805 * @buf - the string that holds the function filter text.
4806 * @len - the length of the string.
4807 * @reset - non zero to reset all filters before applying this filter.
4809 * Filters denote which functions should be enabled when tracing is enabled.
4810 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4812 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
4815 ftrace_ops_init(ops);
4816 return ftrace_set_regex(ops, buf, len, reset, 1);
4818 EXPORT_SYMBOL_GPL(ftrace_set_filter);
4821 * ftrace_set_notrace - set a function to not trace in ftrace
4822 * @ops - the ops to set the notrace filter with
4823 * @buf - the string that holds the function notrace text.
4824 * @len - the length of the string.
4825 * @reset - non zero to reset all filters before applying this filter.
4827 * Notrace Filters denote which functions should not be enabled when tracing
4828 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4831 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
4834 ftrace_ops_init(ops);
4835 return ftrace_set_regex(ops, buf, len, reset, 0);
4837 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
4839 * ftrace_set_global_filter - set a function to filter on with global tracers
4840 * @buf - the string that holds the function filter text.
4841 * @len - the length of the string.
4842 * @reset - non zero to reset all filters before applying this filter.
4844 * Filters denote which functions should be enabled when tracing is enabled.
4845 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4847 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
4849 ftrace_set_regex(&global_ops, buf, len, reset, 1);
4851 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
4854 * ftrace_set_global_notrace - set a function to not trace with global tracers
4855 * @buf - the string that holds the function notrace text.
4856 * @len - the length of the string.
4857 * @reset - non zero to reset all filters before applying this filter.
4859 * Notrace Filters denote which functions should not be enabled when tracing
4860 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4863 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
4865 ftrace_set_regex(&global_ops, buf, len, reset, 0);
4867 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
4870 * command line interface to allow users to set filters on boot up.
4872 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
4873 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4874 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
4876 /* Used by function selftest to not test if filter is set */
4877 bool ftrace_filter_param __initdata;
4879 static int __init set_ftrace_notrace(char *str)
4881 ftrace_filter_param = true;
4882 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
4885 __setup("ftrace_notrace=", set_ftrace_notrace);
4887 static int __init set_ftrace_filter(char *str)
4889 ftrace_filter_param = true;
4890 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
4893 __setup("ftrace_filter=", set_ftrace_filter);
4895 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4896 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
4897 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4898 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
4900 static int __init set_graph_function(char *str)
4902 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
4905 __setup("ftrace_graph_filter=", set_graph_function);
4907 static int __init set_graph_notrace_function(char *str)
4909 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
4912 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
4914 static int __init set_graph_max_depth_function(char *str)
4918 fgraph_max_depth = simple_strtoul(str, NULL, 0);
4921 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
4923 static void __init set_ftrace_early_graph(char *buf, int enable)
4927 struct ftrace_hash *hash;
4929 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4934 func = strsep(&buf, ",");
4935 /* we allow only one expression at a time */
4936 ret = ftrace_graph_set_hash(hash, func);
4938 printk(KERN_DEBUG "ftrace: function %s not "
4939 "traceable\n", func);
4943 ftrace_graph_hash = hash;
4945 ftrace_graph_notrace_hash = hash;
4947 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4950 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
4954 ftrace_ops_init(ops);
4957 func = strsep(&buf, ",");
4958 ftrace_set_regex(ops, func, strlen(func), 0, enable);
4962 static void __init set_ftrace_early_filters(void)
4964 if (ftrace_filter_buf[0])
4965 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
4966 if (ftrace_notrace_buf[0])
4967 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
4968 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4969 if (ftrace_graph_buf[0])
4970 set_ftrace_early_graph(ftrace_graph_buf, 1);
4971 if (ftrace_graph_notrace_buf[0])
4972 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
4973 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4976 int ftrace_regex_release(struct inode *inode, struct file *file)
4978 struct seq_file *m = (struct seq_file *)file->private_data;
4979 struct ftrace_iterator *iter;
4980 struct ftrace_hash **orig_hash;
4981 struct trace_parser *parser;
4985 if (file->f_mode & FMODE_READ) {
4987 seq_release(inode, file);
4989 iter = file->private_data;
4991 parser = &iter->parser;
4992 if (trace_parser_loaded(parser)) {
4993 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
4996 trace_parser_put(parser);
4998 mutex_lock(&iter->ops->func_hash->regex_lock);
5000 if (file->f_mode & FMODE_WRITE) {
5001 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5004 orig_hash = &iter->ops->func_hash->filter_hash;
5005 if (iter->tr && !list_empty(&iter->tr->mod_trace))
5006 iter->hash->flags |= FTRACE_HASH_FL_MOD;
5008 orig_hash = &iter->ops->func_hash->notrace_hash;
5010 mutex_lock(&ftrace_lock);
5011 ret = ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5012 iter->hash, filter_hash);
5013 mutex_unlock(&ftrace_lock);
5015 /* For read only, the hash is the ops hash */
5019 mutex_unlock(&iter->ops->func_hash->regex_lock);
5020 free_ftrace_hash(iter->hash);
5026 static const struct file_operations ftrace_avail_fops = {
5027 .open = ftrace_avail_open,
5029 .llseek = seq_lseek,
5030 .release = seq_release_private,
5033 static const struct file_operations ftrace_enabled_fops = {
5034 .open = ftrace_enabled_open,
5036 .llseek = seq_lseek,
5037 .release = seq_release_private,
5040 static const struct file_operations ftrace_filter_fops = {
5041 .open = ftrace_filter_open,
5043 .write = ftrace_filter_write,
5044 .llseek = tracing_lseek,
5045 .release = ftrace_regex_release,
5048 static const struct file_operations ftrace_notrace_fops = {
5049 .open = ftrace_notrace_open,
5051 .write = ftrace_notrace_write,
5052 .llseek = tracing_lseek,
5053 .release = ftrace_regex_release,
5056 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5058 static DEFINE_MUTEX(graph_lock);
5060 struct ftrace_hash *ftrace_graph_hash = EMPTY_HASH;
5061 struct ftrace_hash *ftrace_graph_notrace_hash = EMPTY_HASH;
5063 enum graph_filter_type {
5064 GRAPH_FILTER_NOTRACE = 0,
5065 GRAPH_FILTER_FUNCTION,
5068 #define FTRACE_GRAPH_EMPTY ((void *)1)
5070 struct ftrace_graph_data {
5071 struct ftrace_hash *hash;
5072 struct ftrace_func_entry *entry;
5073 int idx; /* for hash table iteration */
5074 enum graph_filter_type type;
5075 struct ftrace_hash *new_hash;
5076 const struct seq_operations *seq_ops;
5077 struct trace_parser parser;
5081 __g_next(struct seq_file *m, loff_t *pos)
5083 struct ftrace_graph_data *fgd = m->private;
5084 struct ftrace_func_entry *entry = fgd->entry;
5085 struct hlist_head *head;
5086 int i, idx = fgd->idx;
5088 if (*pos >= fgd->hash->count)
5092 hlist_for_each_entry_continue(entry, hlist) {
5100 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
5101 head = &fgd->hash->buckets[i];
5102 hlist_for_each_entry(entry, head, hlist) {
5112 g_next(struct seq_file *m, void *v, loff_t *pos)
5115 return __g_next(m, pos);
5118 static void *g_start(struct seq_file *m, loff_t *pos)
5120 struct ftrace_graph_data *fgd = m->private;
5122 mutex_lock(&graph_lock);
5124 if (fgd->type == GRAPH_FILTER_FUNCTION)
5125 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5126 lockdep_is_held(&graph_lock));
5128 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5129 lockdep_is_held(&graph_lock));
5131 /* Nothing, tell g_show to print all functions are enabled */
5132 if (ftrace_hash_empty(fgd->hash) && !*pos)
5133 return FTRACE_GRAPH_EMPTY;
5137 return __g_next(m, pos);
5140 static void g_stop(struct seq_file *m, void *p)
5142 mutex_unlock(&graph_lock);
5145 static int g_show(struct seq_file *m, void *v)
5147 struct ftrace_func_entry *entry = v;
5152 if (entry == FTRACE_GRAPH_EMPTY) {
5153 struct ftrace_graph_data *fgd = m->private;
5155 if (fgd->type == GRAPH_FILTER_FUNCTION)
5156 seq_puts(m, "#### all functions enabled ####\n");
5158 seq_puts(m, "#### no functions disabled ####\n");
5162 seq_printf(m, "%ps\n", (void *)entry->ip);
5167 static const struct seq_operations ftrace_graph_seq_ops = {
5175 __ftrace_graph_open(struct inode *inode, struct file *file,
5176 struct ftrace_graph_data *fgd)
5179 struct ftrace_hash *new_hash = NULL;
5181 if (file->f_mode & FMODE_WRITE) {
5182 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
5184 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
5187 if (file->f_flags & O_TRUNC)
5188 new_hash = alloc_ftrace_hash(size_bits);
5190 new_hash = alloc_and_copy_ftrace_hash(size_bits,
5198 if (file->f_mode & FMODE_READ) {
5199 ret = seq_open(file, &ftrace_graph_seq_ops);
5201 struct seq_file *m = file->private_data;
5205 free_ftrace_hash(new_hash);
5209 file->private_data = fgd;
5212 if (ret < 0 && file->f_mode & FMODE_WRITE)
5213 trace_parser_put(&fgd->parser);
5215 fgd->new_hash = new_hash;
5218 * All uses of fgd->hash must be taken with the graph_lock
5219 * held. The graph_lock is going to be released, so force
5220 * fgd->hash to be reinitialized when it is taken again.
5228 ftrace_graph_open(struct inode *inode, struct file *file)
5230 struct ftrace_graph_data *fgd;
5233 if (unlikely(ftrace_disabled))
5236 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5240 mutex_lock(&graph_lock);
5242 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5243 lockdep_is_held(&graph_lock));
5244 fgd->type = GRAPH_FILTER_FUNCTION;
5245 fgd->seq_ops = &ftrace_graph_seq_ops;
5247 ret = __ftrace_graph_open(inode, file, fgd);
5251 mutex_unlock(&graph_lock);
5256 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
5258 struct ftrace_graph_data *fgd;
5261 if (unlikely(ftrace_disabled))
5264 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5268 mutex_lock(&graph_lock);
5270 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5271 lockdep_is_held(&graph_lock));
5272 fgd->type = GRAPH_FILTER_NOTRACE;
5273 fgd->seq_ops = &ftrace_graph_seq_ops;
5275 ret = __ftrace_graph_open(inode, file, fgd);
5279 mutex_unlock(&graph_lock);
5284 ftrace_graph_release(struct inode *inode, struct file *file)
5286 struct ftrace_graph_data *fgd;
5287 struct ftrace_hash *old_hash, *new_hash;
5288 struct trace_parser *parser;
5291 if (file->f_mode & FMODE_READ) {
5292 struct seq_file *m = file->private_data;
5295 seq_release(inode, file);
5297 fgd = file->private_data;
5301 if (file->f_mode & FMODE_WRITE) {
5303 parser = &fgd->parser;
5305 if (trace_parser_loaded((parser))) {
5306 ret = ftrace_graph_set_hash(fgd->new_hash,
5310 trace_parser_put(parser);
5312 new_hash = __ftrace_hash_move(fgd->new_hash);
5318 mutex_lock(&graph_lock);
5320 if (fgd->type == GRAPH_FILTER_FUNCTION) {
5321 old_hash = rcu_dereference_protected(ftrace_graph_hash,
5322 lockdep_is_held(&graph_lock));
5323 rcu_assign_pointer(ftrace_graph_hash, new_hash);
5325 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5326 lockdep_is_held(&graph_lock));
5327 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
5330 mutex_unlock(&graph_lock);
5332 /* Wait till all users are no longer using the old hash */
5335 free_ftrace_hash(old_hash);
5339 free_ftrace_hash(fgd->new_hash);
5346 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
5348 struct ftrace_glob func_g;
5349 struct dyn_ftrace *rec;
5350 struct ftrace_page *pg;
5351 struct ftrace_func_entry *entry;
5356 func_g.type = filter_parse_regex(buffer, strlen(buffer),
5357 &func_g.search, ¬);
5359 func_g.len = strlen(func_g.search);
5361 mutex_lock(&ftrace_lock);
5363 if (unlikely(ftrace_disabled)) {
5364 mutex_unlock(&ftrace_lock);
5368 do_for_each_ftrace_rec(pg, rec) {
5370 if (rec->flags & FTRACE_FL_DISABLED)
5373 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
5374 entry = ftrace_lookup_ip(hash, rec->ip);
5381 if (add_hash_entry(hash, rec->ip) < 0)
5385 free_hash_entry(hash, entry);
5390 } while_for_each_ftrace_rec();
5392 mutex_unlock(&ftrace_lock);
5401 ftrace_graph_write(struct file *file, const char __user *ubuf,
5402 size_t cnt, loff_t *ppos)
5404 ssize_t read, ret = 0;
5405 struct ftrace_graph_data *fgd = file->private_data;
5406 struct trace_parser *parser;
5411 /* Read mode uses seq functions */
5412 if (file->f_mode & FMODE_READ) {
5413 struct seq_file *m = file->private_data;
5417 parser = &fgd->parser;
5419 read = trace_get_user(parser, ubuf, cnt, ppos);
5421 if (read >= 0 && trace_parser_loaded(parser) &&
5422 !trace_parser_cont(parser)) {
5424 ret = ftrace_graph_set_hash(fgd->new_hash,
5426 trace_parser_clear(parser);
5435 static const struct file_operations ftrace_graph_fops = {
5436 .open = ftrace_graph_open,
5438 .write = ftrace_graph_write,
5439 .llseek = tracing_lseek,
5440 .release = ftrace_graph_release,
5443 static const struct file_operations ftrace_graph_notrace_fops = {
5444 .open = ftrace_graph_notrace_open,
5446 .write = ftrace_graph_write,
5447 .llseek = tracing_lseek,
5448 .release = ftrace_graph_release,
5450 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5452 void ftrace_create_filter_files(struct ftrace_ops *ops,
5453 struct dentry *parent)
5456 trace_create_file("set_ftrace_filter", 0644, parent,
5457 ops, &ftrace_filter_fops);
5459 trace_create_file("set_ftrace_notrace", 0644, parent,
5460 ops, &ftrace_notrace_fops);
5464 * The name "destroy_filter_files" is really a misnomer. Although
5465 * in the future, it may actually delete the files, but this is
5466 * really intended to make sure the ops passed in are disabled
5467 * and that when this function returns, the caller is free to
5470 * The "destroy" name is only to match the "create" name that this
5471 * should be paired with.
5473 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
5475 mutex_lock(&ftrace_lock);
5476 if (ops->flags & FTRACE_OPS_FL_ENABLED)
5477 ftrace_shutdown(ops, 0);
5478 ops->flags |= FTRACE_OPS_FL_DELETED;
5479 ftrace_free_filter(ops);
5480 mutex_unlock(&ftrace_lock);
5483 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
5486 trace_create_file("available_filter_functions", 0444,
5487 d_tracer, NULL, &ftrace_avail_fops);
5489 trace_create_file("enabled_functions", 0444,
5490 d_tracer, NULL, &ftrace_enabled_fops);
5492 ftrace_create_filter_files(&global_ops, d_tracer);
5494 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5495 trace_create_file("set_graph_function", 0644, d_tracer,
5497 &ftrace_graph_fops);
5498 trace_create_file("set_graph_notrace", 0644, d_tracer,
5500 &ftrace_graph_notrace_fops);
5501 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5506 static int ftrace_cmp_ips(const void *a, const void *b)
5508 const unsigned long *ipa = a;
5509 const unsigned long *ipb = b;
5518 static int ftrace_process_locs(struct module *mod,
5519 unsigned long *start,
5522 struct ftrace_page *start_pg;
5523 struct ftrace_page *pg;
5524 struct dyn_ftrace *rec;
5525 unsigned long count;
5528 unsigned long flags = 0; /* Shut up gcc */
5531 count = end - start;
5536 sort(start, count, sizeof(*start),
5537 ftrace_cmp_ips, NULL);
5539 start_pg = ftrace_allocate_pages(count);
5543 mutex_lock(&ftrace_lock);
5546 * Core and each module needs their own pages, as
5547 * modules will free them when they are removed.
5548 * Force a new page to be allocated for modules.
5551 WARN_ON(ftrace_pages || ftrace_pages_start);
5552 /* First initialization */
5553 ftrace_pages = ftrace_pages_start = start_pg;
5558 if (WARN_ON(ftrace_pages->next)) {
5559 /* Hmm, we have free pages? */
5560 while (ftrace_pages->next)
5561 ftrace_pages = ftrace_pages->next;
5564 ftrace_pages->next = start_pg;
5570 addr = ftrace_call_adjust(*p++);
5572 * Some architecture linkers will pad between
5573 * the different mcount_loc sections of different
5574 * object files to satisfy alignments.
5575 * Skip any NULL pointers.
5580 if (pg->index == pg->size) {
5581 /* We should have allocated enough */
5582 if (WARN_ON(!pg->next))
5587 rec = &pg->records[pg->index++];
5591 /* We should have used all pages */
5594 /* Assign the last page to ftrace_pages */
5598 * We only need to disable interrupts on start up
5599 * because we are modifying code that an interrupt
5600 * may execute, and the modification is not atomic.
5601 * But for modules, nothing runs the code we modify
5602 * until we are finished with it, and there's no
5603 * reason to cause large interrupt latencies while we do it.
5606 local_irq_save(flags);
5607 ftrace_update_code(mod, start_pg);
5609 local_irq_restore(flags);
5612 mutex_unlock(&ftrace_lock);
5617 struct ftrace_mod_func {
5618 struct list_head list;
5624 struct ftrace_mod_map {
5625 struct rcu_head rcu;
5626 struct list_head list;
5628 unsigned long start_addr;
5629 unsigned long end_addr;
5630 struct list_head funcs;
5631 unsigned int num_funcs;
5634 #ifdef CONFIG_MODULES
5636 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
5638 static LIST_HEAD(ftrace_mod_maps);
5640 static int referenced_filters(struct dyn_ftrace *rec)
5642 struct ftrace_ops *ops;
5645 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
5646 if (ops_references_rec(ops, rec))
5654 clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
5656 struct ftrace_func_entry *entry;
5657 struct dyn_ftrace *rec;
5660 if (ftrace_hash_empty(hash))
5663 for (i = 0; i < pg->index; i++) {
5664 rec = &pg->records[i];
5665 entry = __ftrace_lookup_ip(hash, rec->ip);
5667 * Do not allow this rec to match again.
5668 * Yeah, it may waste some memory, but will be removed
5669 * if/when the hash is modified again.
5676 /* Clear any records from hashs */
5677 static void clear_mod_from_hashes(struct ftrace_page *pg)
5679 struct trace_array *tr;
5681 mutex_lock(&trace_types_lock);
5682 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
5683 if (!tr->ops || !tr->ops->func_hash)
5685 mutex_lock(&tr->ops->func_hash->regex_lock);
5686 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
5687 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
5688 mutex_unlock(&tr->ops->func_hash->regex_lock);
5690 mutex_unlock(&trace_types_lock);
5693 static void ftrace_free_mod_map(struct rcu_head *rcu)
5695 struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
5696 struct ftrace_mod_func *mod_func;
5697 struct ftrace_mod_func *n;
5699 /* All the contents of mod_map are now not visible to readers */
5700 list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
5701 kfree(mod_func->name);
5702 list_del(&mod_func->list);
5709 void ftrace_release_mod(struct module *mod)
5711 struct ftrace_mod_map *mod_map;
5712 struct ftrace_mod_map *n;
5713 struct dyn_ftrace *rec;
5714 struct ftrace_page **last_pg;
5715 struct ftrace_page *tmp_page = NULL;
5716 struct ftrace_page *pg;
5719 mutex_lock(&ftrace_lock);
5721 if (ftrace_disabled)
5724 list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
5725 if (mod_map->mod == mod) {
5726 list_del_rcu(&mod_map->list);
5727 call_rcu(&mod_map->rcu, ftrace_free_mod_map);
5733 * Each module has its own ftrace_pages, remove
5734 * them from the list.
5736 last_pg = &ftrace_pages_start;
5737 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
5738 rec = &pg->records[0];
5739 if (within_module_core(rec->ip, mod) ||
5740 within_module_init(rec->ip, mod)) {
5742 * As core pages are first, the first
5743 * page should never be a module page.
5745 if (WARN_ON(pg == ftrace_pages_start))
5748 /* Check if we are deleting the last page */
5749 if (pg == ftrace_pages)
5750 ftrace_pages = next_to_ftrace_page(last_pg);
5752 ftrace_update_tot_cnt -= pg->index;
5753 *last_pg = pg->next;
5755 pg->next = tmp_page;
5758 last_pg = &pg->next;
5761 mutex_unlock(&ftrace_lock);
5763 for (pg = tmp_page; pg; pg = tmp_page) {
5765 /* Needs to be called outside of ftrace_lock */
5766 clear_mod_from_hashes(pg);
5768 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
5769 free_pages((unsigned long)pg->records, order);
5770 tmp_page = pg->next;
5775 void ftrace_module_enable(struct module *mod)
5777 struct dyn_ftrace *rec;
5778 struct ftrace_page *pg;
5780 mutex_lock(&ftrace_lock);
5782 if (ftrace_disabled)
5786 * If the tracing is enabled, go ahead and enable the record.
5788 * The reason not to enable the record immediately is the
5789 * inherent check of ftrace_make_nop/ftrace_make_call for
5790 * correct previous instructions. Making first the NOP
5791 * conversion puts the module to the correct state, thus
5792 * passing the ftrace_make_call check.
5794 * We also delay this to after the module code already set the
5795 * text to read-only, as we now need to set it back to read-write
5796 * so that we can modify the text.
5798 if (ftrace_start_up)
5799 ftrace_arch_code_modify_prepare();
5801 do_for_each_ftrace_rec(pg, rec) {
5804 * do_for_each_ftrace_rec() is a double loop.
5805 * module text shares the pg. If a record is
5806 * not part of this module, then skip this pg,
5807 * which the "break" will do.
5809 if (!within_module_core(rec->ip, mod) &&
5810 !within_module_init(rec->ip, mod))
5816 * When adding a module, we need to check if tracers are
5817 * currently enabled and if they are, and can trace this record,
5818 * we need to enable the module functions as well as update the
5819 * reference counts for those function records.
5821 if (ftrace_start_up)
5822 cnt += referenced_filters(rec);
5824 /* This clears FTRACE_FL_DISABLED */
5827 if (ftrace_start_up && cnt) {
5828 int failed = __ftrace_replace_code(rec, 1);
5830 ftrace_bug(failed, rec);
5835 } while_for_each_ftrace_rec();
5838 if (ftrace_start_up)
5839 ftrace_arch_code_modify_post_process();
5842 mutex_unlock(&ftrace_lock);
5844 process_cached_mods(mod->name);
5847 void ftrace_module_init(struct module *mod)
5849 if (ftrace_disabled || !mod->num_ftrace_callsites)
5852 ftrace_process_locs(mod, mod->ftrace_callsites,
5853 mod->ftrace_callsites + mod->num_ftrace_callsites);
5856 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
5857 struct dyn_ftrace *rec)
5859 struct ftrace_mod_func *mod_func;
5860 unsigned long symsize;
5861 unsigned long offset;
5862 char str[KSYM_SYMBOL_LEN];
5866 ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
5870 mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
5874 mod_func->name = kstrdup(str, GFP_KERNEL);
5875 if (!mod_func->name) {
5880 mod_func->ip = rec->ip - offset;
5881 mod_func->size = symsize;
5883 mod_map->num_funcs++;
5885 list_add_rcu(&mod_func->list, &mod_map->funcs);
5888 static struct ftrace_mod_map *
5889 allocate_ftrace_mod_map(struct module *mod,
5890 unsigned long start, unsigned long end)
5892 struct ftrace_mod_map *mod_map;
5894 mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
5899 mod_map->start_addr = start;
5900 mod_map->end_addr = end;
5901 mod_map->num_funcs = 0;
5903 INIT_LIST_HEAD_RCU(&mod_map->funcs);
5905 list_add_rcu(&mod_map->list, &ftrace_mod_maps);
5911 ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
5912 unsigned long addr, unsigned long *size,
5913 unsigned long *off, char *sym)
5915 struct ftrace_mod_func *found_func = NULL;
5916 struct ftrace_mod_func *mod_func;
5918 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
5919 if (addr >= mod_func->ip &&
5920 addr < mod_func->ip + mod_func->size) {
5921 found_func = mod_func;
5928 *size = found_func->size;
5930 *off = addr - found_func->ip;
5932 strlcpy(sym, found_func->name, KSYM_NAME_LEN);
5934 return found_func->name;
5941 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
5942 unsigned long *off, char **modname, char *sym)
5944 struct ftrace_mod_map *mod_map;
5945 const char *ret = NULL;
5947 /* mod_map is freed via call_rcu() */
5949 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
5950 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
5953 *modname = mod_map->mod->name;
5962 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
5963 char *type, char *name,
5964 char *module_name, int *exported)
5966 struct ftrace_mod_map *mod_map;
5967 struct ftrace_mod_func *mod_func;
5970 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
5972 if (symnum >= mod_map->num_funcs) {
5973 symnum -= mod_map->num_funcs;
5977 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
5983 *value = mod_func->ip;
5985 strlcpy(name, mod_func->name, KSYM_NAME_LEN);
5986 strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
5999 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6000 struct dyn_ftrace *rec) { }
6001 static inline struct ftrace_mod_map *
6002 allocate_ftrace_mod_map(struct module *mod,
6003 unsigned long start, unsigned long end)
6007 #endif /* CONFIG_MODULES */
6009 struct ftrace_init_func {
6010 struct list_head list;
6014 /* Clear any init ips from hashes */
6016 clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
6018 struct ftrace_func_entry *entry;
6020 if (ftrace_hash_empty(hash))
6023 entry = __ftrace_lookup_ip(hash, func->ip);
6026 * Do not allow this rec to match again.
6027 * Yeah, it may waste some memory, but will be removed
6028 * if/when the hash is modified again.
6035 clear_func_from_hashes(struct ftrace_init_func *func)
6037 struct trace_array *tr;
6039 mutex_lock(&trace_types_lock);
6040 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6041 if (!tr->ops || !tr->ops->func_hash)
6043 mutex_lock(&tr->ops->func_hash->regex_lock);
6044 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
6045 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
6046 mutex_unlock(&tr->ops->func_hash->regex_lock);
6048 mutex_unlock(&trace_types_lock);
6051 static void add_to_clear_hash_list(struct list_head *clear_list,
6052 struct dyn_ftrace *rec)
6054 struct ftrace_init_func *func;
6056 func = kmalloc(sizeof(*func), GFP_KERNEL);
6058 WARN_ONCE(1, "alloc failure, ftrace filter could be stale\n");
6063 list_add(&func->list, clear_list);
6066 void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
6068 unsigned long start = (unsigned long)(start_ptr);
6069 unsigned long end = (unsigned long)(end_ptr);
6070 struct ftrace_page **last_pg = &ftrace_pages_start;
6071 struct ftrace_page *pg;
6072 struct dyn_ftrace *rec;
6073 struct dyn_ftrace key;
6074 struct ftrace_mod_map *mod_map = NULL;
6075 struct ftrace_init_func *func, *func_next;
6076 struct list_head clear_hash;
6079 INIT_LIST_HEAD(&clear_hash);
6082 key.flags = end; /* overload flags, as it is unsigned long */
6084 mutex_lock(&ftrace_lock);
6087 * If we are freeing module init memory, then check if
6088 * any tracer is active. If so, we need to save a mapping of
6089 * the module functions being freed with the address.
6091 if (mod && ftrace_ops_list != &ftrace_list_end)
6092 mod_map = allocate_ftrace_mod_map(mod, start, end);
6094 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
6095 if (end < pg->records[0].ip ||
6096 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
6099 rec = bsearch(&key, pg->records, pg->index,
6100 sizeof(struct dyn_ftrace),
6105 /* rec will be cleared from hashes after ftrace_lock unlock */
6106 add_to_clear_hash_list(&clear_hash, rec);
6109 save_ftrace_mod_rec(mod_map, rec);
6112 ftrace_update_tot_cnt--;
6114 *last_pg = pg->next;
6115 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
6116 free_pages((unsigned long)pg->records, order);
6118 pg = container_of(last_pg, struct ftrace_page, next);
6123 memmove(rec, rec + 1,
6124 (pg->index - (rec - pg->records)) * sizeof(*rec));
6125 /* More than one function may be in this block */
6128 mutex_unlock(&ftrace_lock);
6130 list_for_each_entry_safe(func, func_next, &clear_hash, list) {
6131 clear_func_from_hashes(func);
6136 void __init ftrace_free_init_mem(void)
6138 void *start = (void *)(&__init_begin);
6139 void *end = (void *)(&__init_end);
6141 ftrace_free_mem(NULL, start, end);
6144 void __init ftrace_init(void)
6146 extern unsigned long __start_mcount_loc[];
6147 extern unsigned long __stop_mcount_loc[];
6148 unsigned long count, flags;
6151 local_irq_save(flags);
6152 ret = ftrace_dyn_arch_init();
6153 local_irq_restore(flags);
6157 count = __stop_mcount_loc - __start_mcount_loc;
6159 pr_info("ftrace: No functions to be traced?\n");
6163 pr_info("ftrace: allocating %ld entries in %ld pages\n",
6164 count, count / ENTRIES_PER_PAGE + 1);
6166 last_ftrace_enabled = ftrace_enabled = 1;
6168 ret = ftrace_process_locs(NULL,
6172 set_ftrace_early_filters();
6176 ftrace_disabled = 1;
6179 /* Do nothing if arch does not support this */
6180 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
6184 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6186 arch_ftrace_update_trampoline(ops);
6189 void ftrace_init_trace_array(struct trace_array *tr)
6191 INIT_LIST_HEAD(&tr->func_probes);
6192 INIT_LIST_HEAD(&tr->mod_trace);
6193 INIT_LIST_HEAD(&tr->mod_notrace);
6197 struct ftrace_ops global_ops = {
6198 .func = ftrace_stub,
6199 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
6200 FTRACE_OPS_FL_INITIALIZED |
6204 static int __init ftrace_nodyn_init(void)
6209 core_initcall(ftrace_nodyn_init);
6211 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
6212 static inline void ftrace_startup_enable(int command) { }
6213 static inline void ftrace_startup_all(int command) { }
6215 # define ftrace_startup_sysctl() do { } while (0)
6216 # define ftrace_shutdown_sysctl() do { } while (0)
6218 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6222 #endif /* CONFIG_DYNAMIC_FTRACE */
6224 __init void ftrace_init_global_array_ops(struct trace_array *tr)
6226 tr->ops = &global_ops;
6227 tr->ops->private = tr;
6228 ftrace_init_trace_array(tr);
6231 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
6233 /* If we filter on pids, update to use the pid function */
6234 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
6235 if (WARN_ON(tr->ops->func != ftrace_stub))
6236 printk("ftrace ops had %pS for function\n",
6239 tr->ops->func = func;
6240 tr->ops->private = tr;
6243 void ftrace_reset_array_ops(struct trace_array *tr)
6245 tr->ops->func = ftrace_stub;
6248 static nokprobe_inline void
6249 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6250 struct ftrace_ops *ignored, struct pt_regs *regs)
6252 struct ftrace_ops *op;
6255 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
6260 * Some of the ops may be dynamically allocated,
6261 * they must be freed after a synchronize_rcu().
6263 preempt_disable_notrace();
6265 do_for_each_ftrace_op(op, ftrace_ops_list) {
6266 /* Stub functions don't need to be called nor tested */
6267 if (op->flags & FTRACE_OPS_FL_STUB)
6270 * Check the following for each ops before calling their func:
6271 * if RCU flag is set, then rcu_is_watching() must be true
6272 * if PER_CPU is set, then ftrace_function_local_disable()
6274 * Otherwise test if the ip matches the ops filter
6276 * If any of the above fails then the op->func() is not executed.
6278 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
6279 ftrace_ops_test(op, ip, regs)) {
6280 if (FTRACE_WARN_ON(!op->func)) {
6281 pr_warn("op=%p %pS\n", op, op);
6284 op->func(ip, parent_ip, op, regs);
6286 } while_for_each_ftrace_op(op);
6288 preempt_enable_notrace();
6289 trace_clear_recursion(bit);
6293 * Some archs only support passing ip and parent_ip. Even though
6294 * the list function ignores the op parameter, we do not want any
6295 * C side effects, where a function is called without the caller
6296 * sending a third parameter.
6297 * Archs are to support both the regs and ftrace_ops at the same time.
6298 * If they support ftrace_ops, it is assumed they support regs.
6299 * If call backs want to use regs, they must either check for regs
6300 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
6301 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
6302 * An architecture can pass partial regs with ftrace_ops and still
6303 * set the ARCH_SUPPORTS_FTRACE_OPS.
6305 #if ARCH_SUPPORTS_FTRACE_OPS
6306 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6307 struct ftrace_ops *op, struct pt_regs *regs)
6309 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
6311 NOKPROBE_SYMBOL(ftrace_ops_list_func);
6313 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
6315 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
6317 NOKPROBE_SYMBOL(ftrace_ops_no_ops);
6321 * If there's only one function registered but it does not support
6322 * recursion, needs RCU protection and/or requires per cpu handling, then
6323 * this function will be called by the mcount trampoline.
6325 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
6326 struct ftrace_ops *op, struct pt_regs *regs)
6330 if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching())
6333 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
6337 preempt_disable_notrace();
6339 op->func(ip, parent_ip, op, regs);
6341 preempt_enable_notrace();
6342 trace_clear_recursion(bit);
6344 NOKPROBE_SYMBOL(ftrace_ops_assist_func);
6347 * ftrace_ops_get_func - get the function a trampoline should call
6348 * @ops: the ops to get the function for
6350 * Normally the mcount trampoline will call the ops->func, but there
6351 * are times that it should not. For example, if the ops does not
6352 * have its own recursion protection, then it should call the
6353 * ftrace_ops_assist_func() instead.
6355 * Returns the function that the trampoline should call for @ops.
6357 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
6360 * If the function does not handle recursion, needs to be RCU safe,
6361 * or does per cpu logic, then we need to call the assist handler.
6363 if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
6364 ops->flags & FTRACE_OPS_FL_RCU)
6365 return ftrace_ops_assist_func;
6371 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
6372 struct task_struct *prev, struct task_struct *next)
6374 struct trace_array *tr = data;
6375 struct trace_pid_list *pid_list;
6377 pid_list = rcu_dereference_sched(tr->function_pids);
6379 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
6380 trace_ignore_this_task(pid_list, next));
6384 ftrace_pid_follow_sched_process_fork(void *data,
6385 struct task_struct *self,
6386 struct task_struct *task)
6388 struct trace_pid_list *pid_list;
6389 struct trace_array *tr = data;
6391 pid_list = rcu_dereference_sched(tr->function_pids);
6392 trace_filter_add_remove_task(pid_list, self, task);
6396 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
6398 struct trace_pid_list *pid_list;
6399 struct trace_array *tr = data;
6401 pid_list = rcu_dereference_sched(tr->function_pids);
6402 trace_filter_add_remove_task(pid_list, NULL, task);
6405 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
6408 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6410 register_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit,
6413 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6415 unregister_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit,
6420 static void clear_ftrace_pids(struct trace_array *tr)
6422 struct trace_pid_list *pid_list;
6425 pid_list = rcu_dereference_protected(tr->function_pids,
6426 lockdep_is_held(&ftrace_lock));
6430 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
6432 for_each_possible_cpu(cpu)
6433 per_cpu_ptr(tr->trace_buffer.data, cpu)->ftrace_ignore_pid = false;
6435 rcu_assign_pointer(tr->function_pids, NULL);
6437 /* Wait till all users are no longer using pid filtering */
6440 trace_free_pid_list(pid_list);
6443 void ftrace_clear_pids(struct trace_array *tr)
6445 mutex_lock(&ftrace_lock);
6447 clear_ftrace_pids(tr);
6449 mutex_unlock(&ftrace_lock);
6452 static void ftrace_pid_reset(struct trace_array *tr)
6454 mutex_lock(&ftrace_lock);
6455 clear_ftrace_pids(tr);
6457 ftrace_update_pid_func();
6458 ftrace_startup_all(0);
6460 mutex_unlock(&ftrace_lock);
6463 /* Greater than any max PID */
6464 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
6466 static void *fpid_start(struct seq_file *m, loff_t *pos)
6469 struct trace_pid_list *pid_list;
6470 struct trace_array *tr = m->private;
6472 mutex_lock(&ftrace_lock);
6473 rcu_read_lock_sched();
6475 pid_list = rcu_dereference_sched(tr->function_pids);
6478 return !(*pos) ? FTRACE_NO_PIDS : NULL;
6480 return trace_pid_start(pid_list, pos);
6483 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
6485 struct trace_array *tr = m->private;
6486 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
6488 if (v == FTRACE_NO_PIDS)
6491 return trace_pid_next(pid_list, v, pos);
6494 static void fpid_stop(struct seq_file *m, void *p)
6497 rcu_read_unlock_sched();
6498 mutex_unlock(&ftrace_lock);
6501 static int fpid_show(struct seq_file *m, void *v)
6503 if (v == FTRACE_NO_PIDS) {
6504 seq_puts(m, "no pid\n");
6508 return trace_pid_show(m, v);
6511 static const struct seq_operations ftrace_pid_sops = {
6512 .start = fpid_start,
6519 ftrace_pid_open(struct inode *inode, struct file *file)
6521 struct trace_array *tr = inode->i_private;
6525 if (trace_array_get(tr) < 0)
6528 if ((file->f_mode & FMODE_WRITE) &&
6529 (file->f_flags & O_TRUNC))
6530 ftrace_pid_reset(tr);
6532 ret = seq_open(file, &ftrace_pid_sops);
6534 trace_array_put(tr);
6536 m = file->private_data;
6537 /* copy tr over to seq ops */
6544 static void ignore_task_cpu(void *data)
6546 struct trace_array *tr = data;
6547 struct trace_pid_list *pid_list;
6550 * This function is called by on_each_cpu() while the
6551 * event_mutex is held.
6553 pid_list = rcu_dereference_protected(tr->function_pids,
6554 mutex_is_locked(&ftrace_lock));
6556 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
6557 trace_ignore_this_task(pid_list, current));
6561 ftrace_pid_write(struct file *filp, const char __user *ubuf,
6562 size_t cnt, loff_t *ppos)
6564 struct seq_file *m = filp->private_data;
6565 struct trace_array *tr = m->private;
6566 struct trace_pid_list *filtered_pids = NULL;
6567 struct trace_pid_list *pid_list;
6573 mutex_lock(&ftrace_lock);
6575 filtered_pids = rcu_dereference_protected(tr->function_pids,
6576 lockdep_is_held(&ftrace_lock));
6578 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
6582 rcu_assign_pointer(tr->function_pids, pid_list);
6584 if (filtered_pids) {
6586 trace_free_pid_list(filtered_pids);
6587 } else if (pid_list) {
6588 /* Register a probe to set whether to ignore the tracing of a task */
6589 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
6593 * Ignoring of pids is done at task switch. But we have to
6594 * check for those tasks that are currently running.
6595 * Always do this in case a pid was appended or removed.
6597 on_each_cpu(ignore_task_cpu, tr, 1);
6599 ftrace_update_pid_func();
6600 ftrace_startup_all(0);
6602 mutex_unlock(&ftrace_lock);
6611 ftrace_pid_release(struct inode *inode, struct file *file)
6613 struct trace_array *tr = inode->i_private;
6615 trace_array_put(tr);
6617 return seq_release(inode, file);
6620 static const struct file_operations ftrace_pid_fops = {
6621 .open = ftrace_pid_open,
6622 .write = ftrace_pid_write,
6624 .llseek = tracing_lseek,
6625 .release = ftrace_pid_release,
6628 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
6630 trace_create_file("set_ftrace_pid", 0644, d_tracer,
6631 tr, &ftrace_pid_fops);
6634 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
6635 struct dentry *d_tracer)
6637 /* Only the top level directory has the dyn_tracefs and profile */
6638 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
6640 ftrace_init_dyn_tracefs(d_tracer);
6641 ftrace_profile_tracefs(d_tracer);
6645 * ftrace_kill - kill ftrace
6647 * This function should be used by panic code. It stops ftrace
6648 * but in a not so nice way. If you need to simply kill ftrace
6649 * from a non-atomic section, use ftrace_kill.
6651 void ftrace_kill(void)
6653 ftrace_disabled = 1;
6655 ftrace_trace_function = ftrace_stub;
6659 * Test if ftrace is dead or not.
6661 int ftrace_is_dead(void)
6663 return ftrace_disabled;
6667 * register_ftrace_function - register a function for profiling
6668 * @ops - ops structure that holds the function for profiling.
6670 * Register a function to be called by all functions in the
6673 * Note: @ops->func and all the functions it calls must be labeled
6674 * with "notrace", otherwise it will go into a
6677 int register_ftrace_function(struct ftrace_ops *ops)
6681 ftrace_ops_init(ops);
6683 mutex_lock(&ftrace_lock);
6685 ret = ftrace_startup(ops, 0);
6687 mutex_unlock(&ftrace_lock);
6691 EXPORT_SYMBOL_GPL(register_ftrace_function);
6694 * unregister_ftrace_function - unregister a function for profiling.
6695 * @ops - ops structure that holds the function to unregister
6697 * Unregister a function that was added to be called by ftrace profiling.
6699 int unregister_ftrace_function(struct ftrace_ops *ops)
6703 mutex_lock(&ftrace_lock);
6704 ret = ftrace_shutdown(ops, 0);
6705 mutex_unlock(&ftrace_lock);
6709 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
6712 ftrace_enable_sysctl(struct ctl_table *table, int write,
6713 void __user *buffer, size_t *lenp,
6718 mutex_lock(&ftrace_lock);
6720 if (unlikely(ftrace_disabled))
6723 ret = proc_dointvec(table, write, buffer, lenp, ppos);
6725 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
6728 last_ftrace_enabled = !!ftrace_enabled;
6730 if (ftrace_enabled) {
6732 /* we are starting ftrace again */
6733 if (rcu_dereference_protected(ftrace_ops_list,
6734 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
6735 update_ftrace_function();
6737 ftrace_startup_sysctl();
6740 /* stopping ftrace calls (just send to ftrace_stub) */
6741 ftrace_trace_function = ftrace_stub;
6743 ftrace_shutdown_sysctl();
6747 mutex_unlock(&ftrace_lock);