1 // SPDX-License-Identifier: GPL-2.0
3 * Infrastructure for profiling code inserted by 'gcc -pg'.
5 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
6 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
8 * Originally ported from the -rt patch by:
9 * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
11 * Based on code in the latency_tracer, that is:
13 * Copyright (C) 2004-2006 Ingo Molnar
14 * Copyright (C) 2004 Nadia Yvette Chambers
17 #include <linux/stop_machine.h>
18 #include <linux/clocksource.h>
19 #include <linux/sched/task.h>
20 #include <linux/kallsyms.h>
21 #include <linux/security.h>
22 #include <linux/seq_file.h>
23 #include <linux/tracefs.h>
24 #include <linux/hardirq.h>
25 #include <linux/kthread.h>
26 #include <linux/uaccess.h>
27 #include <linux/bsearch.h>
28 #include <linux/module.h>
29 #include <linux/ftrace.h>
30 #include <linux/sysctl.h>
31 #include <linux/slab.h>
32 #include <linux/ctype.h>
33 #include <linux/sort.h>
34 #include <linux/list.h>
35 #include <linux/hash.h>
36 #include <linux/rcupdate.h>
37 #include <linux/kprobes.h>
39 #include <trace/events/sched.h>
41 #include <asm/sections.h>
42 #include <asm/setup.h>
44 #include "ftrace_internal.h"
45 #include "trace_output.h"
46 #include "trace_stat.h"
48 #define FTRACE_WARN_ON(cond) \
56 #define FTRACE_WARN_ON_ONCE(cond) \
59 if (WARN_ON_ONCE(___r)) \
64 /* hash bits for specific function selection */
65 #define FTRACE_HASH_DEFAULT_BITS 10
66 #define FTRACE_HASH_MAX_BITS 12
68 #ifdef CONFIG_DYNAMIC_FTRACE
69 #define INIT_OPS_HASH(opsname) \
70 .func_hash = &opsname.local_hash, \
71 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
73 #define INIT_OPS_HASH(opsname)
77 FTRACE_MODIFY_ENABLE_FL = (1 << 0),
78 FTRACE_MODIFY_MAY_SLEEP_FL = (1 << 1),
81 struct ftrace_ops ftrace_list_end __read_mostly = {
83 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
84 INIT_OPS_HASH(ftrace_list_end)
87 /* ftrace_enabled is a method to turn ftrace on or off */
88 int ftrace_enabled __read_mostly;
89 static int last_ftrace_enabled;
91 /* Current function tracing op */
92 struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
93 /* What to set function_trace_op to */
94 static struct ftrace_ops *set_function_trace_op;
96 static bool ftrace_pids_enabled(struct ftrace_ops *ops)
98 struct trace_array *tr;
100 if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
105 return tr->function_pids != NULL;
108 static void ftrace_update_trampoline(struct ftrace_ops *ops);
111 * ftrace_disabled is set when an anomaly is discovered.
112 * ftrace_disabled is much stronger than ftrace_enabled.
114 static int ftrace_disabled __read_mostly;
116 DEFINE_MUTEX(ftrace_lock);
118 struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
119 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
120 struct ftrace_ops global_ops;
122 #if ARCH_SUPPORTS_FTRACE_OPS
123 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
124 struct ftrace_ops *op, struct pt_regs *regs);
126 /* See comment below, where ftrace_ops_list_func is defined */
127 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
128 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
131 static inline void ftrace_ops_init(struct ftrace_ops *ops)
133 #ifdef CONFIG_DYNAMIC_FTRACE
134 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
135 mutex_init(&ops->local_hash.regex_lock);
136 ops->func_hash = &ops->local_hash;
137 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
142 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
143 struct ftrace_ops *op, struct pt_regs *regs)
145 struct trace_array *tr = op->private;
147 if (tr && this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid))
150 op->saved_func(ip, parent_ip, op, regs);
153 static void ftrace_sync(struct work_struct *work)
156 * This function is just a stub to implement a hard force
157 * of synchronize_rcu(). This requires synchronizing
158 * tasks even in userspace and idle.
160 * Yes, function tracing is rude.
164 static void ftrace_sync_ipi(void *data)
166 /* Probably not needed, but do it anyway */
170 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
173 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
174 * then it needs to call the list anyway.
176 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
177 FTRACE_FORCE_LIST_FUNC)
178 return ftrace_ops_list_func;
180 return ftrace_ops_get_func(ops);
183 static void update_ftrace_function(void)
188 * Prepare the ftrace_ops that the arch callback will use.
189 * If there's only one ftrace_ops registered, the ftrace_ops_list
190 * will point to the ops we want.
192 set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
193 lockdep_is_held(&ftrace_lock));
195 /* If there's no ftrace_ops registered, just call the stub function */
196 if (set_function_trace_op == &ftrace_list_end) {
200 * If we are at the end of the list and this ops is
201 * recursion safe and not dynamic and the arch supports passing ops,
202 * then have the mcount trampoline call the function directly.
204 } else if (rcu_dereference_protected(ftrace_ops_list->next,
205 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
206 func = ftrace_ops_get_list_func(ftrace_ops_list);
209 /* Just use the default ftrace_ops */
210 set_function_trace_op = &ftrace_list_end;
211 func = ftrace_ops_list_func;
214 update_function_graph_func();
216 /* If there's no change, then do nothing more here */
217 if (ftrace_trace_function == func)
221 * If we are using the list function, it doesn't care
222 * about the function_trace_ops.
224 if (func == ftrace_ops_list_func) {
225 ftrace_trace_function = func;
227 * Don't even bother setting function_trace_ops,
228 * it would be racy to do so anyway.
233 #ifndef CONFIG_DYNAMIC_FTRACE
235 * For static tracing, we need to be a bit more careful.
236 * The function change takes affect immediately. Thus,
237 * we need to coorditate the setting of the function_trace_ops
238 * with the setting of the ftrace_trace_function.
240 * Set the function to the list ops, which will call the
241 * function we want, albeit indirectly, but it handles the
242 * ftrace_ops and doesn't depend on function_trace_op.
244 ftrace_trace_function = ftrace_ops_list_func;
246 * Make sure all CPUs see this. Yes this is slow, but static
247 * tracing is slow and nasty to have enabled.
249 schedule_on_each_cpu(ftrace_sync);
250 /* Now all cpus are using the list ops. */
251 function_trace_op = set_function_trace_op;
252 /* Make sure the function_trace_op is visible on all CPUs */
254 /* Nasty way to force a rmb on all cpus */
255 smp_call_function(ftrace_sync_ipi, NULL, 1);
256 /* OK, we are all set to update the ftrace_trace_function now! */
257 #endif /* !CONFIG_DYNAMIC_FTRACE */
259 ftrace_trace_function = func;
262 static void add_ftrace_ops(struct ftrace_ops __rcu **list,
263 struct ftrace_ops *ops)
265 rcu_assign_pointer(ops->next, *list);
268 * We are entering ops into the list but another
269 * CPU might be walking that list. We need to make sure
270 * the ops->next pointer is valid before another CPU sees
271 * the ops pointer included into the list.
273 rcu_assign_pointer(*list, ops);
276 static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
277 struct ftrace_ops *ops)
279 struct ftrace_ops **p;
282 * If we are removing the last function, then simply point
283 * to the ftrace_stub.
285 if (rcu_dereference_protected(*list,
286 lockdep_is_held(&ftrace_lock)) == ops &&
287 rcu_dereference_protected(ops->next,
288 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
289 *list = &ftrace_list_end;
293 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
304 static void ftrace_update_trampoline(struct ftrace_ops *ops);
306 int __register_ftrace_function(struct ftrace_ops *ops)
308 if (ops->flags & FTRACE_OPS_FL_DELETED)
311 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
314 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
316 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
317 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
318 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
320 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
321 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
324 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
325 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
327 if (!ftrace_enabled && (ops->flags & FTRACE_OPS_FL_PERMANENT))
330 if (!core_kernel_data((unsigned long)ops))
331 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
333 add_ftrace_ops(&ftrace_ops_list, ops);
335 /* Always save the function, and reset at unregistering */
336 ops->saved_func = ops->func;
338 if (ftrace_pids_enabled(ops))
339 ops->func = ftrace_pid_func;
341 ftrace_update_trampoline(ops);
344 update_ftrace_function();
349 int __unregister_ftrace_function(struct ftrace_ops *ops)
353 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
356 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
362 update_ftrace_function();
364 ops->func = ops->saved_func;
369 static void ftrace_update_pid_func(void)
371 struct ftrace_ops *op;
373 /* Only do something if we are tracing something */
374 if (ftrace_trace_function == ftrace_stub)
377 do_for_each_ftrace_op(op, ftrace_ops_list) {
378 if (op->flags & FTRACE_OPS_FL_PID) {
379 op->func = ftrace_pids_enabled(op) ?
380 ftrace_pid_func : op->saved_func;
381 ftrace_update_trampoline(op);
383 } while_for_each_ftrace_op(op);
385 update_ftrace_function();
388 #ifdef CONFIG_FUNCTION_PROFILER
389 struct ftrace_profile {
390 struct hlist_node node;
392 unsigned long counter;
393 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
394 unsigned long long time;
395 unsigned long long time_squared;
399 struct ftrace_profile_page {
400 struct ftrace_profile_page *next;
402 struct ftrace_profile records[];
405 struct ftrace_profile_stat {
407 struct hlist_head *hash;
408 struct ftrace_profile_page *pages;
409 struct ftrace_profile_page *start;
410 struct tracer_stat stat;
413 #define PROFILE_RECORDS_SIZE \
414 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
416 #define PROFILES_PER_PAGE \
417 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
419 static int ftrace_profile_enabled __read_mostly;
421 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
422 static DEFINE_MUTEX(ftrace_profile_lock);
424 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
426 #define FTRACE_PROFILE_HASH_BITS 10
427 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
430 function_stat_next(void *v, int idx)
432 struct ftrace_profile *rec = v;
433 struct ftrace_profile_page *pg;
435 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
441 if ((void *)rec >= (void *)&pg->records[pg->index]) {
445 rec = &pg->records[0];
453 static void *function_stat_start(struct tracer_stat *trace)
455 struct ftrace_profile_stat *stat =
456 container_of(trace, struct ftrace_profile_stat, stat);
458 if (!stat || !stat->start)
461 return function_stat_next(&stat->start->records[0], 0);
464 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
465 /* function graph compares on total time */
466 static int function_stat_cmp(const void *p1, const void *p2)
468 const struct ftrace_profile *a = p1;
469 const struct ftrace_profile *b = p2;
471 if (a->time < b->time)
473 if (a->time > b->time)
479 /* not function graph compares against hits */
480 static int function_stat_cmp(const void *p1, const void *p2)
482 const struct ftrace_profile *a = p1;
483 const struct ftrace_profile *b = p2;
485 if (a->counter < b->counter)
487 if (a->counter > b->counter)
494 static int function_stat_headers(struct seq_file *m)
496 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
497 seq_puts(m, " Function "
500 "--- ---- --- ---\n");
502 seq_puts(m, " Function Hit\n"
508 static int function_stat_show(struct seq_file *m, void *v)
510 struct ftrace_profile *rec = v;
511 char str[KSYM_SYMBOL_LEN];
513 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
514 static struct trace_seq s;
515 unsigned long long avg;
516 unsigned long long stddev;
518 mutex_lock(&ftrace_profile_lock);
520 /* we raced with function_profile_reset() */
521 if (unlikely(rec->counter == 0)) {
526 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
527 avg = div64_ul(rec->time, 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 stddev = div64_ul(stddev,
554 rec->counter * (rec->counter - 1) * 1000);
558 trace_print_graph_duration(rec->time, &s);
559 trace_seq_puts(&s, " ");
560 trace_print_graph_duration(avg, &s);
561 trace_seq_puts(&s, " ");
562 trace_print_graph_duration(stddev, &s);
563 trace_print_seq(m, &s);
567 mutex_unlock(&ftrace_profile_lock);
572 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
574 struct ftrace_profile_page *pg;
576 pg = stat->pages = stat->start;
579 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
584 memset(stat->hash, 0,
585 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
588 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
590 struct ftrace_profile_page *pg;
595 /* If we already allocated, do nothing */
599 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
603 #ifdef CONFIG_DYNAMIC_FTRACE
604 functions = ftrace_update_tot_cnt;
607 * We do not know the number of functions that exist because
608 * dynamic tracing is what counts them. With past experience
609 * we have around 20K functions. That should be more than enough.
610 * It is highly unlikely we will execute every function in
616 pg = stat->start = stat->pages;
618 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
620 for (i = 1; i < pages; i++) {
621 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
632 unsigned long tmp = (unsigned long)pg;
644 static int ftrace_profile_init_cpu(int cpu)
646 struct ftrace_profile_stat *stat;
649 stat = &per_cpu(ftrace_profile_stats, cpu);
652 /* If the profile is already created, simply reset it */
653 ftrace_profile_reset(stat);
658 * We are profiling all functions, but usually only a few thousand
659 * functions are hit. We'll make a hash of 1024 items.
661 size = FTRACE_PROFILE_HASH_SIZE;
663 stat->hash = kcalloc(size, sizeof(struct hlist_head), GFP_KERNEL);
668 /* Preallocate the function profiling pages */
669 if (ftrace_profile_pages_init(stat) < 0) {
678 static int ftrace_profile_init(void)
683 for_each_possible_cpu(cpu) {
684 ret = ftrace_profile_init_cpu(cpu);
692 /* interrupts must be disabled */
693 static struct ftrace_profile *
694 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
696 struct ftrace_profile *rec;
697 struct hlist_head *hhd;
700 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
701 hhd = &stat->hash[key];
703 if (hlist_empty(hhd))
706 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
714 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
715 struct ftrace_profile *rec)
719 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
720 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
724 * The memory is already allocated, this simply finds a new record to use.
726 static struct ftrace_profile *
727 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
729 struct ftrace_profile *rec = NULL;
731 /* prevent recursion (from NMIs) */
732 if (atomic_inc_return(&stat->disabled) != 1)
736 * Try to find the function again since an NMI
737 * could have added it
739 rec = ftrace_find_profiled_func(stat, ip);
743 if (stat->pages->index == PROFILES_PER_PAGE) {
744 if (!stat->pages->next)
746 stat->pages = stat->pages->next;
749 rec = &stat->pages->records[stat->pages->index++];
751 ftrace_add_profile(stat, rec);
754 atomic_dec(&stat->disabled);
760 function_profile_call(unsigned long ip, unsigned long parent_ip,
761 struct ftrace_ops *ops, struct pt_regs *regs)
763 struct ftrace_profile_stat *stat;
764 struct ftrace_profile *rec;
767 if (!ftrace_profile_enabled)
770 local_irq_save(flags);
772 stat = this_cpu_ptr(&ftrace_profile_stats);
773 if (!stat->hash || !ftrace_profile_enabled)
776 rec = ftrace_find_profiled_func(stat, ip);
778 rec = ftrace_profile_alloc(stat, ip);
785 local_irq_restore(flags);
788 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
789 static bool fgraph_graph_time = true;
791 void ftrace_graph_graph_time_control(bool enable)
793 fgraph_graph_time = enable;
796 static int profile_graph_entry(struct ftrace_graph_ent *trace)
798 struct ftrace_ret_stack *ret_stack;
800 function_profile_call(trace->func, 0, NULL, NULL);
802 /* If function graph is shutting down, ret_stack can be NULL */
803 if (!current->ret_stack)
806 ret_stack = ftrace_graph_get_ret_stack(current, 0);
808 ret_stack->subtime = 0;
813 static void profile_graph_return(struct ftrace_graph_ret *trace)
815 struct ftrace_ret_stack *ret_stack;
816 struct ftrace_profile_stat *stat;
817 unsigned long long calltime;
818 struct ftrace_profile *rec;
821 local_irq_save(flags);
822 stat = this_cpu_ptr(&ftrace_profile_stats);
823 if (!stat->hash || !ftrace_profile_enabled)
826 /* If the calltime was zero'd ignore it */
827 if (!trace->calltime)
830 calltime = trace->rettime - trace->calltime;
832 if (!fgraph_graph_time) {
834 /* Append this call time to the parent time to subtract */
835 ret_stack = ftrace_graph_get_ret_stack(current, 1);
837 ret_stack->subtime += calltime;
839 ret_stack = ftrace_graph_get_ret_stack(current, 0);
840 if (ret_stack && ret_stack->subtime < calltime)
841 calltime -= ret_stack->subtime;
846 rec = ftrace_find_profiled_func(stat, trace->func);
848 rec->time += calltime;
849 rec->time_squared += calltime * calltime;
853 local_irq_restore(flags);
856 static struct fgraph_ops fprofiler_ops = {
857 .entryfunc = &profile_graph_entry,
858 .retfunc = &profile_graph_return,
861 static int register_ftrace_profiler(void)
863 return register_ftrace_graph(&fprofiler_ops);
866 static void unregister_ftrace_profiler(void)
868 unregister_ftrace_graph(&fprofiler_ops);
871 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
872 .func = function_profile_call,
873 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
874 INIT_OPS_HASH(ftrace_profile_ops)
877 static int register_ftrace_profiler(void)
879 return register_ftrace_function(&ftrace_profile_ops);
882 static void unregister_ftrace_profiler(void)
884 unregister_ftrace_function(&ftrace_profile_ops);
886 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
889 ftrace_profile_write(struct file *filp, const char __user *ubuf,
890 size_t cnt, loff_t *ppos)
895 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
901 mutex_lock(&ftrace_profile_lock);
902 if (ftrace_profile_enabled ^ val) {
904 ret = ftrace_profile_init();
910 ret = register_ftrace_profiler();
915 ftrace_profile_enabled = 1;
917 ftrace_profile_enabled = 0;
919 * unregister_ftrace_profiler calls stop_machine
920 * so this acts like an synchronize_rcu.
922 unregister_ftrace_profiler();
926 mutex_unlock(&ftrace_profile_lock);
934 ftrace_profile_read(struct file *filp, char __user *ubuf,
935 size_t cnt, loff_t *ppos)
937 char buf[64]; /* big enough to hold a number */
940 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
941 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
944 static const struct file_operations ftrace_profile_fops = {
945 .open = tracing_open_generic,
946 .read = ftrace_profile_read,
947 .write = ftrace_profile_write,
948 .llseek = default_llseek,
951 /* used to initialize the real stat files */
952 static struct tracer_stat function_stats __initdata = {
954 .stat_start = function_stat_start,
955 .stat_next = function_stat_next,
956 .stat_cmp = function_stat_cmp,
957 .stat_headers = function_stat_headers,
958 .stat_show = function_stat_show
961 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
963 struct ftrace_profile_stat *stat;
964 struct dentry *entry;
969 for_each_possible_cpu(cpu) {
970 stat = &per_cpu(ftrace_profile_stats, cpu);
972 name = kasprintf(GFP_KERNEL, "function%d", cpu);
975 * The files created are permanent, if something happens
976 * we still do not free memory.
979 "Could not allocate stat file for cpu %d\n",
983 stat->stat = function_stats;
984 stat->stat.name = name;
985 ret = register_stat_tracer(&stat->stat);
988 "Could not register function stat for cpu %d\n",
995 entry = tracefs_create_file("function_profile_enabled", 0644,
996 d_tracer, NULL, &ftrace_profile_fops);
998 pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
1001 #else /* CONFIG_FUNCTION_PROFILER */
1002 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1005 #endif /* CONFIG_FUNCTION_PROFILER */
1007 #ifdef CONFIG_DYNAMIC_FTRACE
1009 static struct ftrace_ops *removed_ops;
1012 * Set when doing a global update, like enabling all recs or disabling them.
1013 * It is not set when just updating a single ftrace_ops.
1015 static bool update_all_ops;
1017 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1018 # error Dynamic ftrace depends on MCOUNT_RECORD
1021 struct ftrace_func_probe {
1022 struct ftrace_probe_ops *probe_ops;
1023 struct ftrace_ops ops;
1024 struct trace_array *tr;
1025 struct list_head list;
1031 * We make these constant because no one should touch them,
1032 * but they are used as the default "empty hash", to avoid allocating
1033 * it all the time. These are in a read only section such that if
1034 * anyone does try to modify it, it will cause an exception.
1036 static const struct hlist_head empty_buckets[1];
1037 static const struct ftrace_hash empty_hash = {
1038 .buckets = (struct hlist_head *)empty_buckets,
1040 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1042 struct ftrace_ops global_ops = {
1043 .func = ftrace_stub,
1044 .local_hash.notrace_hash = EMPTY_HASH,
1045 .local_hash.filter_hash = EMPTY_HASH,
1046 INIT_OPS_HASH(global_ops)
1047 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
1048 FTRACE_OPS_FL_INITIALIZED |
1053 * Used by the stack undwinder to know about dynamic ftrace trampolines.
1055 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
1057 struct ftrace_ops *op = NULL;
1060 * Some of the ops may be dynamically allocated,
1061 * they are freed after a synchronize_rcu().
1063 preempt_disable_notrace();
1065 do_for_each_ftrace_op(op, ftrace_ops_list) {
1067 * This is to check for dynamically allocated trampolines.
1068 * Trampolines that are in kernel text will have
1069 * core_kernel_text() return true.
1071 if (op->trampoline && op->trampoline_size)
1072 if (addr >= op->trampoline &&
1073 addr < op->trampoline + op->trampoline_size) {
1074 preempt_enable_notrace();
1077 } while_for_each_ftrace_op(op);
1078 preempt_enable_notrace();
1084 * This is used by __kernel_text_address() to return true if the
1085 * address is on a dynamically allocated trampoline that would
1086 * not return true for either core_kernel_text() or
1087 * is_module_text_address().
1089 bool is_ftrace_trampoline(unsigned long addr)
1091 return ftrace_ops_trampoline(addr) != NULL;
1094 struct ftrace_page {
1095 struct ftrace_page *next;
1096 struct dyn_ftrace *records;
1101 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1102 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1104 static struct ftrace_page *ftrace_pages_start;
1105 static struct ftrace_page *ftrace_pages;
1107 static __always_inline unsigned long
1108 ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1110 if (hash->size_bits > 0)
1111 return hash_long(ip, hash->size_bits);
1116 /* Only use this function if ftrace_hash_empty() has already been tested */
1117 static __always_inline struct ftrace_func_entry *
1118 __ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1121 struct ftrace_func_entry *entry;
1122 struct hlist_head *hhd;
1124 key = ftrace_hash_key(hash, ip);
1125 hhd = &hash->buckets[key];
1127 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1128 if (entry->ip == ip)
1135 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1136 * @hash: The hash to look at
1137 * @ip: The instruction pointer to test
1139 * Search a given @hash to see if a given instruction pointer (@ip)
1142 * Returns the entry that holds the @ip if found. NULL otherwise.
1144 struct ftrace_func_entry *
1145 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1147 if (ftrace_hash_empty(hash))
1150 return __ftrace_lookup_ip(hash, ip);
1153 static void __add_hash_entry(struct ftrace_hash *hash,
1154 struct ftrace_func_entry *entry)
1156 struct hlist_head *hhd;
1159 key = ftrace_hash_key(hash, entry->ip);
1160 hhd = &hash->buckets[key];
1161 hlist_add_head(&entry->hlist, hhd);
1165 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1167 struct ftrace_func_entry *entry;
1169 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1174 __add_hash_entry(hash, entry);
1180 free_hash_entry(struct ftrace_hash *hash,
1181 struct ftrace_func_entry *entry)
1183 hlist_del(&entry->hlist);
1189 remove_hash_entry(struct ftrace_hash *hash,
1190 struct ftrace_func_entry *entry)
1192 hlist_del_rcu(&entry->hlist);
1196 static void ftrace_hash_clear(struct ftrace_hash *hash)
1198 struct hlist_head *hhd;
1199 struct hlist_node *tn;
1200 struct ftrace_func_entry *entry;
1201 int size = 1 << hash->size_bits;
1207 for (i = 0; i < size; i++) {
1208 hhd = &hash->buckets[i];
1209 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1210 free_hash_entry(hash, entry);
1212 FTRACE_WARN_ON(hash->count);
1215 static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1217 list_del(&ftrace_mod->list);
1218 kfree(ftrace_mod->module);
1219 kfree(ftrace_mod->func);
1223 static void clear_ftrace_mod_list(struct list_head *head)
1225 struct ftrace_mod_load *p, *n;
1227 /* stack tracer isn't supported yet */
1231 mutex_lock(&ftrace_lock);
1232 list_for_each_entry_safe(p, n, head, list)
1234 mutex_unlock(&ftrace_lock);
1237 static void free_ftrace_hash(struct ftrace_hash *hash)
1239 if (!hash || hash == EMPTY_HASH)
1241 ftrace_hash_clear(hash);
1242 kfree(hash->buckets);
1246 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1248 struct ftrace_hash *hash;
1250 hash = container_of(rcu, struct ftrace_hash, rcu);
1251 free_ftrace_hash(hash);
1254 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1256 if (!hash || hash == EMPTY_HASH)
1258 call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
1261 void ftrace_free_filter(struct ftrace_ops *ops)
1263 ftrace_ops_init(ops);
1264 free_ftrace_hash(ops->func_hash->filter_hash);
1265 free_ftrace_hash(ops->func_hash->notrace_hash);
1268 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1270 struct ftrace_hash *hash;
1273 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1277 size = 1 << size_bits;
1278 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1280 if (!hash->buckets) {
1285 hash->size_bits = size_bits;
1291 static int ftrace_add_mod(struct trace_array *tr,
1292 const char *func, const char *module,
1295 struct ftrace_mod_load *ftrace_mod;
1296 struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1298 ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1302 ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1303 ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1304 ftrace_mod->enable = enable;
1306 if (!ftrace_mod->func || !ftrace_mod->module)
1309 list_add(&ftrace_mod->list, mod_head);
1314 free_ftrace_mod(ftrace_mod);
1319 static struct ftrace_hash *
1320 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1322 struct ftrace_func_entry *entry;
1323 struct ftrace_hash *new_hash;
1328 new_hash = alloc_ftrace_hash(size_bits);
1333 new_hash->flags = hash->flags;
1336 if (ftrace_hash_empty(hash))
1339 size = 1 << hash->size_bits;
1340 for (i = 0; i < size; i++) {
1341 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1342 ret = add_hash_entry(new_hash, entry->ip);
1348 FTRACE_WARN_ON(new_hash->count != hash->count);
1353 free_ftrace_hash(new_hash);
1358 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1360 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1362 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1363 struct ftrace_hash *new_hash);
1365 static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size)
1367 struct ftrace_func_entry *entry;
1368 struct ftrace_hash *new_hash;
1369 struct hlist_head *hhd;
1370 struct hlist_node *tn;
1375 * Make the hash size about 1/2 the # found
1377 for (size /= 2; size; size >>= 1)
1380 /* Don't allocate too much */
1381 if (bits > FTRACE_HASH_MAX_BITS)
1382 bits = FTRACE_HASH_MAX_BITS;
1384 new_hash = alloc_ftrace_hash(bits);
1388 new_hash->flags = src->flags;
1390 size = 1 << src->size_bits;
1391 for (i = 0; i < size; i++) {
1392 hhd = &src->buckets[i];
1393 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1394 remove_hash_entry(src, entry);
1395 __add_hash_entry(new_hash, entry);
1401 static struct ftrace_hash *
1402 __ftrace_hash_move(struct ftrace_hash *src)
1404 int size = src->count;
1407 * If the new source is empty, just return the empty_hash.
1409 if (ftrace_hash_empty(src))
1412 return dup_hash(src, size);
1416 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1417 struct ftrace_hash **dst, struct ftrace_hash *src)
1419 struct ftrace_hash *new_hash;
1422 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1423 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1426 new_hash = __ftrace_hash_move(src);
1430 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1432 /* IPMODIFY should be updated only when filter_hash updating */
1433 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1435 free_ftrace_hash(new_hash);
1441 * Remove the current set, update the hash and add
1444 ftrace_hash_rec_disable_modify(ops, enable);
1446 rcu_assign_pointer(*dst, new_hash);
1448 ftrace_hash_rec_enable_modify(ops, enable);
1453 static bool hash_contains_ip(unsigned long ip,
1454 struct ftrace_ops_hash *hash)
1457 * The function record is a match if it exists in the filter
1458 * hash and not in the notrace hash. Note, an emty hash is
1459 * considered a match for the filter hash, but an empty
1460 * notrace hash is considered not in the notrace hash.
1462 return (ftrace_hash_empty(hash->filter_hash) ||
1463 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1464 (ftrace_hash_empty(hash->notrace_hash) ||
1465 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1469 * Test the hashes for this ops to see if we want to call
1470 * the ops->func or not.
1472 * It's a match if the ip is in the ops->filter_hash or
1473 * the filter_hash does not exist or is empty,
1475 * the ip is not in the ops->notrace_hash.
1477 * This needs to be called with preemption disabled as
1478 * the hashes are freed with call_rcu().
1481 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1483 struct ftrace_ops_hash hash;
1486 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1488 * There's a small race when adding ops that the ftrace handler
1489 * that wants regs, may be called without them. We can not
1490 * allow that handler to be called if regs is NULL.
1492 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1496 rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1497 rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1499 if (hash_contains_ip(ip, &hash))
1508 * This is a double for. Do not use 'break' to break out of the loop,
1509 * you must use a goto.
1511 #define do_for_each_ftrace_rec(pg, rec) \
1512 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1514 for (_____i = 0; _____i < pg->index; _____i++) { \
1515 rec = &pg->records[_____i];
1517 #define while_for_each_ftrace_rec() \
1522 static int ftrace_cmp_recs(const void *a, const void *b)
1524 const struct dyn_ftrace *key = a;
1525 const struct dyn_ftrace *rec = b;
1527 if (key->flags < rec->ip)
1529 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1534 static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
1536 struct ftrace_page *pg;
1537 struct dyn_ftrace *rec = NULL;
1538 struct dyn_ftrace key;
1541 key.flags = end; /* overload flags, as it is unsigned long */
1543 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1544 if (end < pg->records[0].ip ||
1545 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1547 rec = bsearch(&key, pg->records, pg->index,
1548 sizeof(struct dyn_ftrace),
1557 * ftrace_location_range - return the first address of a traced location
1558 * if it touches the given ip range
1559 * @start: start of range to search.
1560 * @end: end of range to search (inclusive). @end points to the last byte
1563 * Returns rec->ip if the related ftrace location is a least partly within
1564 * the given address range. That is, the first address of the instruction
1565 * that is either a NOP or call to the function tracer. It checks the ftrace
1566 * internal tables to determine if the address belongs or not.
1568 unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1570 struct dyn_ftrace *rec;
1572 rec = lookup_rec(start, end);
1580 * ftrace_location - return true if the ip giving is a traced location
1581 * @ip: the instruction pointer to check
1583 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1584 * That is, the instruction that is either a NOP or call to
1585 * the function tracer. It checks the ftrace internal tables to
1586 * determine if the address belongs or not.
1588 unsigned long ftrace_location(unsigned long ip)
1590 return ftrace_location_range(ip, ip);
1594 * ftrace_text_reserved - return true if range contains an ftrace location
1595 * @start: start of range to search
1596 * @end: end of range to search (inclusive). @end points to the last byte to check.
1598 * Returns 1 if @start and @end contains a ftrace location.
1599 * That is, the instruction that is either a NOP or call to
1600 * the function tracer. It checks the ftrace internal tables to
1601 * determine if the address belongs or not.
1603 int ftrace_text_reserved(const void *start, const void *end)
1607 ret = ftrace_location_range((unsigned long)start,
1608 (unsigned long)end);
1613 /* Test if ops registered to this rec needs regs */
1614 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1616 struct ftrace_ops *ops;
1617 bool keep_regs = false;
1619 for (ops = ftrace_ops_list;
1620 ops != &ftrace_list_end; ops = ops->next) {
1621 /* pass rec in as regs to have non-NULL val */
1622 if (ftrace_ops_test(ops, rec->ip, rec)) {
1623 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1633 static struct ftrace_ops *
1634 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1635 static struct ftrace_ops *
1636 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1638 static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1642 struct ftrace_hash *hash;
1643 struct ftrace_hash *other_hash;
1644 struct ftrace_page *pg;
1645 struct dyn_ftrace *rec;
1646 bool update = false;
1650 /* Only update if the ops has been registered */
1651 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1655 * In the filter_hash case:
1656 * If the count is zero, we update all records.
1657 * Otherwise we just update the items in the hash.
1659 * In the notrace_hash case:
1660 * We enable the update in the hash.
1661 * As disabling notrace means enabling the tracing,
1662 * and enabling notrace means disabling, the inc variable
1666 hash = ops->func_hash->filter_hash;
1667 other_hash = ops->func_hash->notrace_hash;
1668 if (ftrace_hash_empty(hash))
1672 hash = ops->func_hash->notrace_hash;
1673 other_hash = ops->func_hash->filter_hash;
1675 * If the notrace hash has no items,
1676 * then there's nothing to do.
1678 if (ftrace_hash_empty(hash))
1682 do_for_each_ftrace_rec(pg, rec) {
1683 int in_other_hash = 0;
1687 if (rec->flags & FTRACE_FL_DISABLED)
1692 * Only the filter_hash affects all records.
1693 * Update if the record is not in the notrace hash.
1695 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1698 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1699 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1702 * If filter_hash is set, we want to match all functions
1703 * that are in the hash but not in the other hash.
1705 * If filter_hash is not set, then we are decrementing.
1706 * That means we match anything that is in the hash
1707 * and also in the other_hash. That is, we need to turn
1708 * off functions in the other hash because they are disabled
1711 if (filter_hash && in_hash && !in_other_hash)
1713 else if (!filter_hash && in_hash &&
1714 (in_other_hash || ftrace_hash_empty(other_hash)))
1722 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1725 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1726 rec->flags |= FTRACE_FL_DIRECT;
1729 * If there's only a single callback registered to a
1730 * function, and the ops has a trampoline registered
1731 * for it, then we can call it directly.
1733 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1734 rec->flags |= FTRACE_FL_TRAMP;
1737 * If we are adding another function callback
1738 * to this function, and the previous had a
1739 * custom trampoline in use, then we need to go
1740 * back to the default trampoline.
1742 rec->flags &= ~FTRACE_FL_TRAMP;
1745 * If any ops wants regs saved for this function
1746 * then all ops will get saved regs.
1748 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1749 rec->flags |= FTRACE_FL_REGS;
1751 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1756 * Only the internal direct_ops should have the
1757 * DIRECT flag set. Thus, if it is removing a
1758 * function, then that function should no longer
1761 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1762 rec->flags &= ~FTRACE_FL_DIRECT;
1765 * If the rec had REGS enabled and the ops that is
1766 * being removed had REGS set, then see if there is
1767 * still any ops for this record that wants regs.
1768 * If not, we can stop recording them.
1770 if (ftrace_rec_count(rec) > 0 &&
1771 rec->flags & FTRACE_FL_REGS &&
1772 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1773 if (!test_rec_ops_needs_regs(rec))
1774 rec->flags &= ~FTRACE_FL_REGS;
1778 * The TRAMP needs to be set only if rec count
1779 * is decremented to one, and the ops that is
1780 * left has a trampoline. As TRAMP can only be
1781 * enabled if there is only a single ops attached
1784 if (ftrace_rec_count(rec) == 1 &&
1785 ftrace_find_tramp_ops_any(rec))
1786 rec->flags |= FTRACE_FL_TRAMP;
1788 rec->flags &= ~FTRACE_FL_TRAMP;
1791 * flags will be cleared in ftrace_check_record()
1792 * if rec count is zero.
1797 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1798 update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1800 /* Shortcut, if we handled all records, we are done. */
1801 if (!all && count == hash->count)
1803 } while_for_each_ftrace_rec();
1808 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1811 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1814 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1817 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1820 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1821 int filter_hash, int inc)
1823 struct ftrace_ops *op;
1825 __ftrace_hash_rec_update(ops, filter_hash, inc);
1827 if (ops->func_hash != &global_ops.local_hash)
1831 * If the ops shares the global_ops hash, then we need to update
1832 * all ops that are enabled and use this hash.
1834 do_for_each_ftrace_op(op, ftrace_ops_list) {
1838 if (op->func_hash == &global_ops.local_hash)
1839 __ftrace_hash_rec_update(op, filter_hash, inc);
1840 } while_for_each_ftrace_op(op);
1843 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1846 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1849 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1852 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1856 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1857 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1858 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1859 * Note that old_hash and new_hash has below meanings
1860 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1861 * - If the hash is EMPTY_HASH, it hits nothing
1862 * - Anything else hits the recs which match the hash entries.
1864 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1865 struct ftrace_hash *old_hash,
1866 struct ftrace_hash *new_hash)
1868 struct ftrace_page *pg;
1869 struct dyn_ftrace *rec, *end = NULL;
1872 /* Only update if the ops has been registered */
1873 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1876 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1880 * Since the IPMODIFY is a very address sensitive action, we do not
1881 * allow ftrace_ops to set all functions to new hash.
1883 if (!new_hash || !old_hash)
1886 /* Update rec->flags */
1887 do_for_each_ftrace_rec(pg, rec) {
1889 if (rec->flags & FTRACE_FL_DISABLED)
1892 /* We need to update only differences of filter_hash */
1893 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1894 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1895 if (in_old == in_new)
1899 /* New entries must ensure no others are using it */
1900 if (rec->flags & FTRACE_FL_IPMODIFY)
1902 rec->flags |= FTRACE_FL_IPMODIFY;
1903 } else /* Removed entry */
1904 rec->flags &= ~FTRACE_FL_IPMODIFY;
1905 } while_for_each_ftrace_rec();
1912 /* Roll back what we did above */
1913 do_for_each_ftrace_rec(pg, rec) {
1915 if (rec->flags & FTRACE_FL_DISABLED)
1921 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1922 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1923 if (in_old == in_new)
1927 rec->flags &= ~FTRACE_FL_IPMODIFY;
1929 rec->flags |= FTRACE_FL_IPMODIFY;
1930 } while_for_each_ftrace_rec();
1936 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1938 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1940 if (ftrace_hash_empty(hash))
1943 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1946 /* Disabling always succeeds */
1947 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1949 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1951 if (ftrace_hash_empty(hash))
1954 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1957 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1958 struct ftrace_hash *new_hash)
1960 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1962 if (ftrace_hash_empty(old_hash))
1965 if (ftrace_hash_empty(new_hash))
1968 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
1971 static void print_ip_ins(const char *fmt, const unsigned char *p)
1975 printk(KERN_CONT "%s", fmt);
1977 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1978 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1981 enum ftrace_bug_type ftrace_bug_type;
1982 const void *ftrace_expected;
1984 static void print_bug_type(void)
1986 switch (ftrace_bug_type) {
1987 case FTRACE_BUG_UNKNOWN:
1989 case FTRACE_BUG_INIT:
1990 pr_info("Initializing ftrace call sites\n");
1992 case FTRACE_BUG_NOP:
1993 pr_info("Setting ftrace call site to NOP\n");
1995 case FTRACE_BUG_CALL:
1996 pr_info("Setting ftrace call site to call ftrace function\n");
1998 case FTRACE_BUG_UPDATE:
1999 pr_info("Updating ftrace call site to call a different ftrace function\n");
2005 * ftrace_bug - report and shutdown function tracer
2006 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2007 * @rec: The record that failed
2009 * The arch code that enables or disables the function tracing
2010 * can call ftrace_bug() when it has detected a problem in
2011 * modifying the code. @failed should be one of either:
2012 * EFAULT - if the problem happens on reading the @ip address
2013 * EINVAL - if what is read at @ip is not what was expected
2014 * EPERM - if the problem happens on writing to the @ip address
2016 void ftrace_bug(int failed, struct dyn_ftrace *rec)
2018 unsigned long ip = rec ? rec->ip : 0;
2022 FTRACE_WARN_ON_ONCE(1);
2023 pr_info("ftrace faulted on modifying ");
2027 FTRACE_WARN_ON_ONCE(1);
2028 pr_info("ftrace failed to modify ");
2030 print_ip_ins(" actual: ", (unsigned char *)ip);
2032 if (ftrace_expected) {
2033 print_ip_ins(" expected: ", ftrace_expected);
2038 FTRACE_WARN_ON_ONCE(1);
2039 pr_info("ftrace faulted on writing ");
2043 FTRACE_WARN_ON_ONCE(1);
2044 pr_info("ftrace faulted on unknown error ");
2049 struct ftrace_ops *ops = NULL;
2051 pr_info("ftrace record flags: %lx\n", rec->flags);
2052 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2053 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2054 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2055 ops = ftrace_find_tramp_ops_any(rec);
2058 pr_cont("\ttramp: %pS (%pS)",
2059 (void *)ops->trampoline,
2061 ops = ftrace_find_tramp_ops_next(rec, ops);
2064 pr_cont("\ttramp: ERROR!");
2067 ip = ftrace_get_addr_curr(rec);
2068 pr_cont("\n expected tramp: %lx\n", ip);
2072 static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2074 unsigned long flag = 0UL;
2076 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2078 if (rec->flags & FTRACE_FL_DISABLED)
2079 return FTRACE_UPDATE_IGNORE;
2082 * If we are updating calls:
2084 * If the record has a ref count, then we need to enable it
2085 * because someone is using it.
2087 * Otherwise we make sure its disabled.
2089 * If we are disabling calls, then disable all records that
2092 if (enable && ftrace_rec_count(rec))
2093 flag = FTRACE_FL_ENABLED;
2096 * If enabling and the REGS flag does not match the REGS_EN, or
2097 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2098 * this record. Set flags to fail the compare against ENABLED.
2099 * Same for direct calls.
2102 if (!(rec->flags & FTRACE_FL_REGS) !=
2103 !(rec->flags & FTRACE_FL_REGS_EN))
2104 flag |= FTRACE_FL_REGS;
2106 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2107 !(rec->flags & FTRACE_FL_TRAMP_EN))
2108 flag |= FTRACE_FL_TRAMP;
2111 * Direct calls are special, as count matters.
2112 * We must test the record for direct, if the
2113 * DIRECT and DIRECT_EN do not match, but only
2114 * if the count is 1. That's because, if the
2115 * count is something other than one, we do not
2116 * want the direct enabled (it will be done via the
2117 * direct helper). But if DIRECT_EN is set, and
2118 * the count is not one, we need to clear it.
2120 if (ftrace_rec_count(rec) == 1) {
2121 if (!(rec->flags & FTRACE_FL_DIRECT) !=
2122 !(rec->flags & FTRACE_FL_DIRECT_EN))
2123 flag |= FTRACE_FL_DIRECT;
2124 } else if (rec->flags & FTRACE_FL_DIRECT_EN) {
2125 flag |= FTRACE_FL_DIRECT;
2129 /* If the state of this record hasn't changed, then do nothing */
2130 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2131 return FTRACE_UPDATE_IGNORE;
2134 /* Save off if rec is being enabled (for return value) */
2135 flag ^= rec->flags & FTRACE_FL_ENABLED;
2138 rec->flags |= FTRACE_FL_ENABLED;
2139 if (flag & FTRACE_FL_REGS) {
2140 if (rec->flags & FTRACE_FL_REGS)
2141 rec->flags |= FTRACE_FL_REGS_EN;
2143 rec->flags &= ~FTRACE_FL_REGS_EN;
2145 if (flag & FTRACE_FL_TRAMP) {
2146 if (rec->flags & FTRACE_FL_TRAMP)
2147 rec->flags |= FTRACE_FL_TRAMP_EN;
2149 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2151 if (flag & FTRACE_FL_DIRECT) {
2153 * If there's only one user (direct_ops helper)
2154 * then we can call the direct function
2155 * directly (no ftrace trampoline).
2157 if (ftrace_rec_count(rec) == 1) {
2158 if (rec->flags & FTRACE_FL_DIRECT)
2159 rec->flags |= FTRACE_FL_DIRECT_EN;
2161 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2164 * Can only call directly if there's
2165 * only one callback to the function.
2167 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2173 * If this record is being updated from a nop, then
2174 * return UPDATE_MAKE_CALL.
2176 * return UPDATE_MODIFY_CALL to tell the caller to convert
2177 * from the save regs, to a non-save regs function or
2178 * vice versa, or from a trampoline call.
2180 if (flag & FTRACE_FL_ENABLED) {
2181 ftrace_bug_type = FTRACE_BUG_CALL;
2182 return FTRACE_UPDATE_MAKE_CALL;
2185 ftrace_bug_type = FTRACE_BUG_UPDATE;
2186 return FTRACE_UPDATE_MODIFY_CALL;
2190 /* If there's no more users, clear all flags */
2191 if (!ftrace_rec_count(rec))
2195 * Just disable the record, but keep the ops TRAMP
2196 * and REGS states. The _EN flags must be disabled though.
2198 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2199 FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN);
2202 ftrace_bug_type = FTRACE_BUG_NOP;
2203 return FTRACE_UPDATE_MAKE_NOP;
2207 * ftrace_update_record, set a record that now is tracing or not
2208 * @rec: the record to update
2209 * @enable: set to true if the record is tracing, false to force disable
2211 * The records that represent all functions that can be traced need
2212 * to be updated when tracing has been enabled.
2214 int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2216 return ftrace_check_record(rec, enable, true);
2220 * ftrace_test_record, check if the record has been enabled or not
2221 * @rec: the record to test
2222 * @enable: set to true to check if enabled, false if it is disabled
2224 * The arch code may need to test if a record is already set to
2225 * tracing to determine how to modify the function code that it
2228 int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2230 return ftrace_check_record(rec, enable, false);
2233 static struct ftrace_ops *
2234 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2236 struct ftrace_ops *op;
2237 unsigned long ip = rec->ip;
2239 do_for_each_ftrace_op(op, ftrace_ops_list) {
2241 if (!op->trampoline)
2244 if (hash_contains_ip(ip, op->func_hash))
2246 } while_for_each_ftrace_op(op);
2251 static struct ftrace_ops *
2252 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2253 struct ftrace_ops *op)
2255 unsigned long ip = rec->ip;
2257 while_for_each_ftrace_op(op) {
2259 if (!op->trampoline)
2262 if (hash_contains_ip(ip, op->func_hash))
2269 static struct ftrace_ops *
2270 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2272 struct ftrace_ops *op;
2273 unsigned long ip = rec->ip;
2276 * Need to check removed ops first.
2277 * If they are being removed, and this rec has a tramp,
2278 * and this rec is in the ops list, then it would be the
2279 * one with the tramp.
2282 if (hash_contains_ip(ip, &removed_ops->old_hash))
2287 * Need to find the current trampoline for a rec.
2288 * Now, a trampoline is only attached to a rec if there
2289 * was a single 'ops' attached to it. But this can be called
2290 * when we are adding another op to the rec or removing the
2291 * current one. Thus, if the op is being added, we can
2292 * ignore it because it hasn't attached itself to the rec
2295 * If an ops is being modified (hooking to different functions)
2296 * then we don't care about the new functions that are being
2297 * added, just the old ones (that are probably being removed).
2299 * If we are adding an ops to a function that already is using
2300 * a trampoline, it needs to be removed (trampolines are only
2301 * for single ops connected), then an ops that is not being
2302 * modified also needs to be checked.
2304 do_for_each_ftrace_op(op, ftrace_ops_list) {
2306 if (!op->trampoline)
2310 * If the ops is being added, it hasn't gotten to
2311 * the point to be removed from this tree yet.
2313 if (op->flags & FTRACE_OPS_FL_ADDING)
2318 * If the ops is being modified and is in the old
2319 * hash, then it is probably being removed from this
2322 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2323 hash_contains_ip(ip, &op->old_hash))
2326 * If the ops is not being added or modified, and it's
2327 * in its normal filter hash, then this must be the one
2330 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2331 hash_contains_ip(ip, op->func_hash))
2334 } while_for_each_ftrace_op(op);
2339 static struct ftrace_ops *
2340 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2342 struct ftrace_ops *op;
2343 unsigned long ip = rec->ip;
2345 do_for_each_ftrace_op(op, ftrace_ops_list) {
2346 /* pass rec in as regs to have non-NULL val */
2347 if (hash_contains_ip(ip, op->func_hash))
2349 } while_for_each_ftrace_op(op);
2354 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
2355 /* Protected by rcu_tasks for reading, and direct_mutex for writing */
2356 static struct ftrace_hash *direct_functions = EMPTY_HASH;
2357 static DEFINE_MUTEX(direct_mutex);
2358 int ftrace_direct_func_count;
2361 * Search the direct_functions hash to see if the given instruction pointer
2362 * has a direct caller attached to it.
2364 unsigned long ftrace_find_rec_direct(unsigned long ip)
2366 struct ftrace_func_entry *entry;
2368 entry = __ftrace_lookup_ip(direct_functions, ip);
2372 return entry->direct;
2375 static void call_direct_funcs(unsigned long ip, unsigned long pip,
2376 struct ftrace_ops *ops, struct pt_regs *regs)
2380 addr = ftrace_find_rec_direct(ip);
2384 arch_ftrace_set_direct_caller(regs, addr);
2387 struct ftrace_ops direct_ops = {
2388 .func = call_direct_funcs,
2389 .flags = FTRACE_OPS_FL_IPMODIFY | FTRACE_OPS_FL_RECURSION_SAFE
2390 | FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
2391 | FTRACE_OPS_FL_PERMANENT,
2393 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
2396 * ftrace_get_addr_new - Get the call address to set to
2397 * @rec: The ftrace record descriptor
2399 * If the record has the FTRACE_FL_REGS set, that means that it
2400 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2401 * is not not set, then it wants to convert to the normal callback.
2403 * Returns the address of the trampoline to set to
2405 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2407 struct ftrace_ops *ops;
2410 if ((rec->flags & FTRACE_FL_DIRECT) &&
2411 (ftrace_rec_count(rec) == 1)) {
2412 addr = ftrace_find_rec_direct(rec->ip);
2418 /* Trampolines take precedence over regs */
2419 if (rec->flags & FTRACE_FL_TRAMP) {
2420 ops = ftrace_find_tramp_ops_new(rec);
2421 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2422 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2423 (void *)rec->ip, (void *)rec->ip, rec->flags);
2424 /* Ftrace is shutting down, return anything */
2425 return (unsigned long)FTRACE_ADDR;
2427 return ops->trampoline;
2430 if (rec->flags & FTRACE_FL_REGS)
2431 return (unsigned long)FTRACE_REGS_ADDR;
2433 return (unsigned long)FTRACE_ADDR;
2437 * ftrace_get_addr_curr - Get the call address that is already there
2438 * @rec: The ftrace record descriptor
2440 * The FTRACE_FL_REGS_EN is set when the record already points to
2441 * a function that saves all the regs. Basically the '_EN' version
2442 * represents the current state of the function.
2444 * Returns the address of the trampoline that is currently being called
2446 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2448 struct ftrace_ops *ops;
2451 /* Direct calls take precedence over trampolines */
2452 if (rec->flags & FTRACE_FL_DIRECT_EN) {
2453 addr = ftrace_find_rec_direct(rec->ip);
2459 /* Trampolines take precedence over regs */
2460 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2461 ops = ftrace_find_tramp_ops_curr(rec);
2462 if (FTRACE_WARN_ON(!ops)) {
2463 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2464 (void *)rec->ip, (void *)rec->ip);
2465 /* Ftrace is shutting down, return anything */
2466 return (unsigned long)FTRACE_ADDR;
2468 return ops->trampoline;
2471 if (rec->flags & FTRACE_FL_REGS_EN)
2472 return (unsigned long)FTRACE_REGS_ADDR;
2474 return (unsigned long)FTRACE_ADDR;
2478 __ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2480 unsigned long ftrace_old_addr;
2481 unsigned long ftrace_addr;
2484 ftrace_addr = ftrace_get_addr_new(rec);
2486 /* This needs to be done before we call ftrace_update_record */
2487 ftrace_old_addr = ftrace_get_addr_curr(rec);
2489 ret = ftrace_update_record(rec, enable);
2491 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2494 case FTRACE_UPDATE_IGNORE:
2497 case FTRACE_UPDATE_MAKE_CALL:
2498 ftrace_bug_type = FTRACE_BUG_CALL;
2499 return ftrace_make_call(rec, ftrace_addr);
2501 case FTRACE_UPDATE_MAKE_NOP:
2502 ftrace_bug_type = FTRACE_BUG_NOP;
2503 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2505 case FTRACE_UPDATE_MODIFY_CALL:
2506 ftrace_bug_type = FTRACE_BUG_UPDATE;
2507 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2510 return -1; /* unknown ftrace bug */
2513 void __weak ftrace_replace_code(int mod_flags)
2515 struct dyn_ftrace *rec;
2516 struct ftrace_page *pg;
2517 bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2518 int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2521 if (unlikely(ftrace_disabled))
2524 do_for_each_ftrace_rec(pg, rec) {
2526 if (rec->flags & FTRACE_FL_DISABLED)
2529 failed = __ftrace_replace_code(rec, enable);
2531 ftrace_bug(failed, rec);
2532 /* Stop processing */
2537 } while_for_each_ftrace_rec();
2540 struct ftrace_rec_iter {
2541 struct ftrace_page *pg;
2546 * ftrace_rec_iter_start, start up iterating over traced functions
2548 * Returns an iterator handle that is used to iterate over all
2549 * the records that represent address locations where functions
2552 * May return NULL if no records are available.
2554 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2557 * We only use a single iterator.
2558 * Protected by the ftrace_lock mutex.
2560 static struct ftrace_rec_iter ftrace_rec_iter;
2561 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2563 iter->pg = ftrace_pages_start;
2566 /* Could have empty pages */
2567 while (iter->pg && !iter->pg->index)
2568 iter->pg = iter->pg->next;
2577 * ftrace_rec_iter_next, get the next record to process.
2578 * @iter: The handle to the iterator.
2580 * Returns the next iterator after the given iterator @iter.
2582 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2586 if (iter->index >= iter->pg->index) {
2587 iter->pg = iter->pg->next;
2590 /* Could have empty pages */
2591 while (iter->pg && !iter->pg->index)
2592 iter->pg = iter->pg->next;
2602 * ftrace_rec_iter_record, get the record at the iterator location
2603 * @iter: The current iterator location
2605 * Returns the record that the current @iter is at.
2607 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2609 return &iter->pg->records[iter->index];
2613 ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
2617 if (unlikely(ftrace_disabled))
2620 ret = ftrace_init_nop(mod, rec);
2622 ftrace_bug_type = FTRACE_BUG_INIT;
2623 ftrace_bug(ret, rec);
2630 * archs can override this function if they must do something
2631 * before the modifying code is performed.
2633 int __weak ftrace_arch_code_modify_prepare(void)
2639 * archs can override this function if they must do something
2640 * after the modifying code is performed.
2642 int __weak ftrace_arch_code_modify_post_process(void)
2647 void ftrace_modify_all_code(int command)
2649 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2653 if (command & FTRACE_MAY_SLEEP)
2654 mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2657 * If the ftrace_caller calls a ftrace_ops func directly,
2658 * we need to make sure that it only traces functions it
2659 * expects to trace. When doing the switch of functions,
2660 * we need to update to the ftrace_ops_list_func first
2661 * before the transition between old and new calls are set,
2662 * as the ftrace_ops_list_func will check the ops hashes
2663 * to make sure the ops are having the right functions
2667 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2668 if (FTRACE_WARN_ON(err))
2672 if (command & FTRACE_UPDATE_CALLS)
2673 ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2674 else if (command & FTRACE_DISABLE_CALLS)
2675 ftrace_replace_code(mod_flags);
2677 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2678 function_trace_op = set_function_trace_op;
2680 /* If irqs are disabled, we are in stop machine */
2681 if (!irqs_disabled())
2682 smp_call_function(ftrace_sync_ipi, NULL, 1);
2683 err = ftrace_update_ftrace_func(ftrace_trace_function);
2684 if (FTRACE_WARN_ON(err))
2688 if (command & FTRACE_START_FUNC_RET)
2689 err = ftrace_enable_ftrace_graph_caller();
2690 else if (command & FTRACE_STOP_FUNC_RET)
2691 err = ftrace_disable_ftrace_graph_caller();
2692 FTRACE_WARN_ON(err);
2695 static int __ftrace_modify_code(void *data)
2697 int *command = data;
2699 ftrace_modify_all_code(*command);
2705 * ftrace_run_stop_machine, go back to the stop machine method
2706 * @command: The command to tell ftrace what to do
2708 * If an arch needs to fall back to the stop machine method, the
2709 * it can call this function.
2711 void ftrace_run_stop_machine(int command)
2713 stop_machine(__ftrace_modify_code, &command, NULL);
2717 * arch_ftrace_update_code, modify the code to trace or not trace
2718 * @command: The command that needs to be done
2720 * Archs can override this function if it does not need to
2721 * run stop_machine() to modify code.
2723 void __weak arch_ftrace_update_code(int command)
2725 ftrace_run_stop_machine(command);
2728 static void ftrace_run_update_code(int command)
2732 ret = ftrace_arch_code_modify_prepare();
2733 FTRACE_WARN_ON(ret);
2738 * By default we use stop_machine() to modify the code.
2739 * But archs can do what ever they want as long as it
2740 * is safe. The stop_machine() is the safest, but also
2741 * produces the most overhead.
2743 arch_ftrace_update_code(command);
2745 ret = ftrace_arch_code_modify_post_process();
2746 FTRACE_WARN_ON(ret);
2749 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2750 struct ftrace_ops_hash *old_hash)
2752 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2753 ops->old_hash.filter_hash = old_hash->filter_hash;
2754 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2755 ftrace_run_update_code(command);
2756 ops->old_hash.filter_hash = NULL;
2757 ops->old_hash.notrace_hash = NULL;
2758 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2761 static ftrace_func_t saved_ftrace_func;
2762 static int ftrace_start_up;
2764 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2768 static void ftrace_startup_enable(int command)
2770 if (saved_ftrace_func != ftrace_trace_function) {
2771 saved_ftrace_func = ftrace_trace_function;
2772 command |= FTRACE_UPDATE_TRACE_FUNC;
2775 if (!command || !ftrace_enabled)
2778 ftrace_run_update_code(command);
2781 static void ftrace_startup_all(int command)
2783 update_all_ops = true;
2784 ftrace_startup_enable(command);
2785 update_all_ops = false;
2788 int ftrace_startup(struct ftrace_ops *ops, int command)
2792 if (unlikely(ftrace_disabled))
2795 ret = __register_ftrace_function(ops);
2802 * Note that ftrace probes uses this to start up
2803 * and modify functions it will probe. But we still
2804 * set the ADDING flag for modification, as probes
2805 * do not have trampolines. If they add them in the
2806 * future, then the probes will need to distinguish
2807 * between adding and updating probes.
2809 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2811 ret = ftrace_hash_ipmodify_enable(ops);
2813 /* Rollback registration process */
2814 __unregister_ftrace_function(ops);
2816 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2820 if (ftrace_hash_rec_enable(ops, 1))
2821 command |= FTRACE_UPDATE_CALLS;
2823 ftrace_startup_enable(command);
2825 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2830 int ftrace_shutdown(struct ftrace_ops *ops, int command)
2834 if (unlikely(ftrace_disabled))
2837 ret = __unregister_ftrace_function(ops);
2843 * Just warn in case of unbalance, no need to kill ftrace, it's not
2844 * critical but the ftrace_call callers may be never nopped again after
2845 * further ftrace uses.
2847 WARN_ON_ONCE(ftrace_start_up < 0);
2849 /* Disabling ipmodify never fails */
2850 ftrace_hash_ipmodify_disable(ops);
2852 if (ftrace_hash_rec_disable(ops, 1))
2853 command |= FTRACE_UPDATE_CALLS;
2855 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2857 if (saved_ftrace_func != ftrace_trace_function) {
2858 saved_ftrace_func = ftrace_trace_function;
2859 command |= FTRACE_UPDATE_TRACE_FUNC;
2862 if (!command || !ftrace_enabled) {
2864 * If these are dynamic or per_cpu ops, they still
2865 * need their data freed. Since, function tracing is
2866 * not currently active, we can just free them
2867 * without synchronizing all CPUs.
2869 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2876 * If the ops uses a trampoline, then it needs to be
2877 * tested first on update.
2879 ops->flags |= FTRACE_OPS_FL_REMOVING;
2882 /* The trampoline logic checks the old hashes */
2883 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2884 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2886 ftrace_run_update_code(command);
2889 * If there's no more ops registered with ftrace, run a
2890 * sanity check to make sure all rec flags are cleared.
2892 if (rcu_dereference_protected(ftrace_ops_list,
2893 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
2894 struct ftrace_page *pg;
2895 struct dyn_ftrace *rec;
2897 do_for_each_ftrace_rec(pg, rec) {
2898 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
2899 pr_warn(" %pS flags:%lx\n",
2900 (void *)rec->ip, rec->flags);
2901 } while_for_each_ftrace_rec();
2904 ops->old_hash.filter_hash = NULL;
2905 ops->old_hash.notrace_hash = NULL;
2908 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2911 * Dynamic ops may be freed, we must make sure that all
2912 * callers are done before leaving this function.
2913 * The same goes for freeing the per_cpu data of the per_cpu
2916 if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
2918 * We need to do a hard force of sched synchronization.
2919 * This is because we use preempt_disable() to do RCU, but
2920 * the function tracers can be called where RCU is not watching
2921 * (like before user_exit()). We can not rely on the RCU
2922 * infrastructure to do the synchronization, thus we must do it
2925 schedule_on_each_cpu(ftrace_sync);
2928 * When the kernel is preeptive, tasks can be preempted
2929 * while on a ftrace trampoline. Just scheduling a task on
2930 * a CPU is not good enough to flush them. Calling
2931 * synchornize_rcu_tasks() will wait for those tasks to
2932 * execute and either schedule voluntarily or enter user space.
2934 if (IS_ENABLED(CONFIG_PREEMPTION))
2935 synchronize_rcu_tasks();
2938 arch_ftrace_trampoline_free(ops);
2944 static void ftrace_startup_sysctl(void)
2948 if (unlikely(ftrace_disabled))
2951 /* Force update next time */
2952 saved_ftrace_func = NULL;
2953 /* ftrace_start_up is true if we want ftrace running */
2954 if (ftrace_start_up) {
2955 command = FTRACE_UPDATE_CALLS;
2956 if (ftrace_graph_active)
2957 command |= FTRACE_START_FUNC_RET;
2958 ftrace_startup_enable(command);
2962 static void ftrace_shutdown_sysctl(void)
2966 if (unlikely(ftrace_disabled))
2969 /* ftrace_start_up is true if ftrace is running */
2970 if (ftrace_start_up) {
2971 command = FTRACE_DISABLE_CALLS;
2972 if (ftrace_graph_active)
2973 command |= FTRACE_STOP_FUNC_RET;
2974 ftrace_run_update_code(command);
2978 static u64 ftrace_update_time;
2979 unsigned long ftrace_update_tot_cnt;
2980 unsigned long ftrace_number_of_pages;
2981 unsigned long ftrace_number_of_groups;
2983 static inline int ops_traces_mod(struct ftrace_ops *ops)
2986 * Filter_hash being empty will default to trace module.
2987 * But notrace hash requires a test of individual module functions.
2989 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
2990 ftrace_hash_empty(ops->func_hash->notrace_hash);
2994 * Check if the current ops references the record.
2996 * If the ops traces all functions, then it was already accounted for.
2997 * If the ops does not trace the current record function, skip it.
2998 * If the ops ignores the function via notrace filter, skip it.
3001 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3003 /* If ops isn't enabled, ignore it */
3004 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
3007 /* If ops traces all then it includes this function */
3008 if (ops_traces_mod(ops))
3011 /* The function must be in the filter */
3012 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
3013 !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
3016 /* If in notrace hash, we ignore it too */
3017 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
3023 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
3025 struct ftrace_page *pg;
3026 struct dyn_ftrace *p;
3028 unsigned long update_cnt = 0;
3029 unsigned long rec_flags = 0;
3032 start = ftrace_now(raw_smp_processor_id());
3035 * When a module is loaded, this function is called to convert
3036 * the calls to mcount in its text to nops, and also to create
3037 * an entry in the ftrace data. Now, if ftrace is activated
3038 * after this call, but before the module sets its text to
3039 * read-only, the modification of enabling ftrace can fail if
3040 * the read-only is done while ftrace is converting the calls.
3041 * To prevent this, the module's records are set as disabled
3042 * and will be enabled after the call to set the module's text
3046 rec_flags |= FTRACE_FL_DISABLED;
3048 for (pg = new_pgs; pg; pg = pg->next) {
3050 for (i = 0; i < pg->index; i++) {
3052 /* If something went wrong, bail without enabling anything */
3053 if (unlikely(ftrace_disabled))
3056 p = &pg->records[i];
3057 p->flags = rec_flags;
3060 * Do the initial record conversion from mcount jump
3061 * to the NOP instructions.
3063 if (!__is_defined(CC_USING_NOP_MCOUNT) &&
3064 !ftrace_nop_initialize(mod, p))
3071 stop = ftrace_now(raw_smp_processor_id());
3072 ftrace_update_time = stop - start;
3073 ftrace_update_tot_cnt += update_cnt;
3078 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3083 if (WARN_ON(!count))
3086 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
3089 * We want to fill as much as possible. No more than a page
3092 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
3096 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3099 /* if we can't allocate this size, try something smaller */
3106 ftrace_number_of_pages += 1 << order;
3107 ftrace_number_of_groups++;
3109 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3118 static struct ftrace_page *
3119 ftrace_allocate_pages(unsigned long num_to_init)
3121 struct ftrace_page *start_pg;
3122 struct ftrace_page *pg;
3129 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3134 * Try to allocate as much as possible in one continues
3135 * location that fills in all of the space. We want to
3136 * waste as little space as possible.
3139 cnt = ftrace_allocate_records(pg, num_to_init);
3147 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3159 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3160 free_pages((unsigned long)pg->records, order);
3161 start_pg = pg->next;
3164 ftrace_number_of_pages -= 1 << order;
3165 ftrace_number_of_groups--;
3167 pr_info("ftrace: FAILED to allocate memory for functions\n");
3171 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3173 struct ftrace_iterator {
3177 struct ftrace_page *pg;
3178 struct dyn_ftrace *func;
3179 struct ftrace_func_probe *probe;
3180 struct ftrace_func_entry *probe_entry;
3181 struct trace_parser parser;
3182 struct ftrace_hash *hash;
3183 struct ftrace_ops *ops;
3184 struct trace_array *tr;
3185 struct list_head *mod_list;
3192 t_probe_next(struct seq_file *m, loff_t *pos)
3194 struct ftrace_iterator *iter = m->private;
3195 struct trace_array *tr = iter->ops->private;
3196 struct list_head *func_probes;
3197 struct ftrace_hash *hash;
3198 struct list_head *next;
3199 struct hlist_node *hnd = NULL;
3200 struct hlist_head *hhd;
3209 func_probes = &tr->func_probes;
3210 if (list_empty(func_probes))
3214 next = func_probes->next;
3215 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3218 if (iter->probe_entry)
3219 hnd = &iter->probe_entry->hlist;
3221 hash = iter->probe->ops.func_hash->filter_hash;
3224 * A probe being registered may temporarily have an empty hash
3225 * and it's at the end of the func_probes list.
3227 if (!hash || hash == EMPTY_HASH)
3230 size = 1 << hash->size_bits;
3233 if (iter->pidx >= size) {
3234 if (iter->probe->list.next == func_probes)
3236 next = iter->probe->list.next;
3237 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3238 hash = iter->probe->ops.func_hash->filter_hash;
3239 size = 1 << hash->size_bits;
3243 hhd = &hash->buckets[iter->pidx];
3245 if (hlist_empty(hhd)) {
3261 if (WARN_ON_ONCE(!hnd))
3264 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3269 static void *t_probe_start(struct seq_file *m, loff_t *pos)
3271 struct ftrace_iterator *iter = m->private;
3275 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3278 if (iter->mod_pos > *pos)
3282 iter->probe_entry = NULL;
3284 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3285 p = t_probe_next(m, &l);
3292 /* Only set this if we have an item */
3293 iter->flags |= FTRACE_ITER_PROBE;
3299 t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3301 struct ftrace_func_entry *probe_entry;
3302 struct ftrace_probe_ops *probe_ops;
3303 struct ftrace_func_probe *probe;
3305 probe = iter->probe;
3306 probe_entry = iter->probe_entry;
3308 if (WARN_ON_ONCE(!probe || !probe_entry))
3311 probe_ops = probe->probe_ops;
3313 if (probe_ops->print)
3314 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3316 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3317 (void *)probe_ops->func);
3323 t_mod_next(struct seq_file *m, loff_t *pos)
3325 struct ftrace_iterator *iter = m->private;
3326 struct trace_array *tr = iter->tr;
3331 iter->mod_list = iter->mod_list->next;
3333 if (iter->mod_list == &tr->mod_trace ||
3334 iter->mod_list == &tr->mod_notrace) {
3335 iter->flags &= ~FTRACE_ITER_MOD;
3339 iter->mod_pos = *pos;
3344 static void *t_mod_start(struct seq_file *m, loff_t *pos)
3346 struct ftrace_iterator *iter = m->private;
3350 if (iter->func_pos > *pos)
3353 iter->mod_pos = iter->func_pos;
3355 /* probes are only available if tr is set */
3359 for (l = 0; l <= (*pos - iter->func_pos); ) {
3360 p = t_mod_next(m, &l);
3365 iter->flags &= ~FTRACE_ITER_MOD;
3366 return t_probe_start(m, pos);
3369 /* Only set this if we have an item */
3370 iter->flags |= FTRACE_ITER_MOD;
3376 t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3378 struct ftrace_mod_load *ftrace_mod;
3379 struct trace_array *tr = iter->tr;
3381 if (WARN_ON_ONCE(!iter->mod_list) ||
3382 iter->mod_list == &tr->mod_trace ||
3383 iter->mod_list == &tr->mod_notrace)
3386 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3388 if (ftrace_mod->func)
3389 seq_printf(m, "%s", ftrace_mod->func);
3393 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3399 t_func_next(struct seq_file *m, loff_t *pos)
3401 struct ftrace_iterator *iter = m->private;
3402 struct dyn_ftrace *rec = NULL;
3407 if (iter->idx >= iter->pg->index) {
3408 if (iter->pg->next) {
3409 iter->pg = iter->pg->next;
3414 rec = &iter->pg->records[iter->idx++];
3415 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3416 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3418 ((iter->flags & FTRACE_ITER_ENABLED) &&
3419 !(rec->flags & FTRACE_FL_ENABLED))) {
3429 iter->pos = iter->func_pos = *pos;
3436 t_next(struct seq_file *m, void *v, loff_t *pos)
3438 struct ftrace_iterator *iter = m->private;
3439 loff_t l = *pos; /* t_probe_start() must use original pos */
3442 if (unlikely(ftrace_disabled))
3445 if (iter->flags & FTRACE_ITER_PROBE)
3446 return t_probe_next(m, pos);
3448 if (iter->flags & FTRACE_ITER_MOD)
3449 return t_mod_next(m, pos);
3451 if (iter->flags & FTRACE_ITER_PRINTALL) {
3452 /* next must increment pos, and t_probe_start does not */
3454 return t_mod_start(m, &l);
3457 ret = t_func_next(m, pos);
3460 return t_mod_start(m, &l);
3465 static void reset_iter_read(struct ftrace_iterator *iter)
3469 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3472 static void *t_start(struct seq_file *m, loff_t *pos)
3474 struct ftrace_iterator *iter = m->private;
3478 mutex_lock(&ftrace_lock);
3480 if (unlikely(ftrace_disabled))
3484 * If an lseek was done, then reset and start from beginning.
3486 if (*pos < iter->pos)
3487 reset_iter_read(iter);
3490 * For set_ftrace_filter reading, if we have the filter
3491 * off, we can short cut and just print out that all
3492 * functions are enabled.
3494 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3495 ftrace_hash_empty(iter->hash)) {
3496 iter->func_pos = 1; /* Account for the message */
3498 return t_mod_start(m, pos);
3499 iter->flags |= FTRACE_ITER_PRINTALL;
3500 /* reset in case of seek/pread */
3501 iter->flags &= ~FTRACE_ITER_PROBE;
3505 if (iter->flags & FTRACE_ITER_MOD)
3506 return t_mod_start(m, pos);
3509 * Unfortunately, we need to restart at ftrace_pages_start
3510 * every time we let go of the ftrace_mutex. This is because
3511 * those pointers can change without the lock.
3513 iter->pg = ftrace_pages_start;
3515 for (l = 0; l <= *pos; ) {
3516 p = t_func_next(m, &l);
3522 return t_mod_start(m, pos);
3527 static void t_stop(struct seq_file *m, void *p)
3529 mutex_unlock(&ftrace_lock);
3533 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3538 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3539 struct dyn_ftrace *rec)
3543 ptr = arch_ftrace_trampoline_func(ops, rec);
3545 seq_printf(m, " ->%pS", ptr);
3548 static int t_show(struct seq_file *m, void *v)
3550 struct ftrace_iterator *iter = m->private;
3551 struct dyn_ftrace *rec;
3553 if (iter->flags & FTRACE_ITER_PROBE)
3554 return t_probe_show(m, iter);
3556 if (iter->flags & FTRACE_ITER_MOD)
3557 return t_mod_show(m, iter);
3559 if (iter->flags & FTRACE_ITER_PRINTALL) {
3560 if (iter->flags & FTRACE_ITER_NOTRACE)
3561 seq_puts(m, "#### no functions disabled ####\n");
3563 seq_puts(m, "#### all functions enabled ####\n");
3572 seq_printf(m, "%ps", (void *)rec->ip);
3573 if (iter->flags & FTRACE_ITER_ENABLED) {
3574 struct ftrace_ops *ops;
3576 seq_printf(m, " (%ld)%s%s%s",
3577 ftrace_rec_count(rec),
3578 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3579 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ",
3580 rec->flags & FTRACE_FL_DIRECT ? " D" : " ");
3581 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3582 ops = ftrace_find_tramp_ops_any(rec);
3585 seq_printf(m, "\ttramp: %pS (%pS)",
3586 (void *)ops->trampoline,
3588 add_trampoline_func(m, ops, rec);
3589 ops = ftrace_find_tramp_ops_next(rec, ops);
3592 seq_puts(m, "\ttramp: ERROR!");
3594 add_trampoline_func(m, NULL, rec);
3596 if (rec->flags & FTRACE_FL_DIRECT) {
3597 unsigned long direct;
3599 direct = ftrace_find_rec_direct(rec->ip);
3601 seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
3610 static const struct seq_operations show_ftrace_seq_ops = {
3618 ftrace_avail_open(struct inode *inode, struct file *file)
3620 struct ftrace_iterator *iter;
3623 ret = security_locked_down(LOCKDOWN_TRACEFS);
3627 if (unlikely(ftrace_disabled))
3630 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3634 iter->pg = ftrace_pages_start;
3635 iter->ops = &global_ops;
3641 ftrace_enabled_open(struct inode *inode, struct file *file)
3643 struct ftrace_iterator *iter;
3646 * This shows us what functions are currently being
3647 * traced and by what. Not sure if we want lockdown
3648 * to hide such critical information for an admin.
3649 * Although, perhaps it can show information we don't
3650 * want people to see, but if something is tracing
3651 * something, we probably want to know about it.
3654 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3658 iter->pg = ftrace_pages_start;
3659 iter->flags = FTRACE_ITER_ENABLED;
3660 iter->ops = &global_ops;
3666 * ftrace_regex_open - initialize function tracer filter files
3667 * @ops: The ftrace_ops that hold the hash filters
3668 * @flag: The type of filter to process
3669 * @inode: The inode, usually passed in to your open routine
3670 * @file: The file, usually passed in to your open routine
3672 * ftrace_regex_open() initializes the filter files for the
3673 * @ops. Depending on @flag it may process the filter hash or
3674 * the notrace hash of @ops. With this called from the open
3675 * routine, you can use ftrace_filter_write() for the write
3676 * routine if @flag has FTRACE_ITER_FILTER set, or
3677 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3678 * tracing_lseek() should be used as the lseek routine, and
3679 * release must call ftrace_regex_release().
3682 ftrace_regex_open(struct ftrace_ops *ops, int flag,
3683 struct inode *inode, struct file *file)
3685 struct ftrace_iterator *iter;
3686 struct ftrace_hash *hash;
3687 struct list_head *mod_head;
3688 struct trace_array *tr = ops->private;
3691 ftrace_ops_init(ops);
3693 if (unlikely(ftrace_disabled))
3696 if (tracing_check_open_get_tr(tr))
3699 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3703 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
3710 mutex_lock(&ops->func_hash->regex_lock);
3712 if (flag & FTRACE_ITER_NOTRACE) {
3713 hash = ops->func_hash->notrace_hash;
3714 mod_head = tr ? &tr->mod_notrace : NULL;
3716 hash = ops->func_hash->filter_hash;
3717 mod_head = tr ? &tr->mod_trace : NULL;
3720 iter->mod_list = mod_head;
3722 if (file->f_mode & FMODE_WRITE) {
3723 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3725 if (file->f_flags & O_TRUNC) {
3726 iter->hash = alloc_ftrace_hash(size_bits);
3727 clear_ftrace_mod_list(mod_head);
3729 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3733 trace_parser_put(&iter->parser);
3741 if (file->f_mode & FMODE_READ) {
3742 iter->pg = ftrace_pages_start;
3744 ret = seq_open(file, &show_ftrace_seq_ops);
3746 struct seq_file *m = file->private_data;
3750 free_ftrace_hash(iter->hash);
3751 trace_parser_put(&iter->parser);
3754 file->private_data = iter;
3757 mutex_unlock(&ops->func_hash->regex_lock);
3763 trace_array_put(tr);
3770 ftrace_filter_open(struct inode *inode, struct file *file)
3772 struct ftrace_ops *ops = inode->i_private;
3774 /* Checks for tracefs lockdown */
3775 return ftrace_regex_open(ops,
3776 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3781 ftrace_notrace_open(struct inode *inode, struct file *file)
3783 struct ftrace_ops *ops = inode->i_private;
3785 /* Checks for tracefs lockdown */
3786 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3790 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3791 struct ftrace_glob {
3798 * If symbols in an architecture don't correspond exactly to the user-visible
3799 * name of what they represent, it is possible to define this function to
3800 * perform the necessary adjustments.
3802 char * __weak arch_ftrace_match_adjust(char *str, const char *search)
3807 static int ftrace_match(char *str, struct ftrace_glob *g)
3812 str = arch_ftrace_match_adjust(str, g->search);
3816 if (strcmp(str, g->search) == 0)
3819 case MATCH_FRONT_ONLY:
3820 if (strncmp(str, g->search, g->len) == 0)
3823 case MATCH_MIDDLE_ONLY:
3824 if (strstr(str, g->search))
3827 case MATCH_END_ONLY:
3829 if (slen >= g->len &&
3830 memcmp(str + slen - g->len, g->search, g->len) == 0)
3834 if (glob_match(g->search, str))
3843 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3845 struct ftrace_func_entry *entry;
3848 entry = ftrace_lookup_ip(hash, rec->ip);
3850 /* Do nothing if it doesn't exist */
3854 free_hash_entry(hash, entry);
3856 /* Do nothing if it exists */
3860 ret = add_hash_entry(hash, rec->ip);
3866 add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
3869 long index = simple_strtoul(func_g->search, NULL, 0);
3870 struct ftrace_page *pg;
3871 struct dyn_ftrace *rec;
3873 /* The index starts at 1 */
3877 do_for_each_ftrace_rec(pg, rec) {
3878 if (pg->index <= index) {
3880 /* this is a double loop, break goes to the next page */
3883 rec = &pg->records[index];
3884 enter_record(hash, rec, clear_filter);
3886 } while_for_each_ftrace_rec();
3891 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3892 struct ftrace_glob *mod_g, int exclude_mod)
3894 char str[KSYM_SYMBOL_LEN];
3897 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3900 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3902 /* blank module name to match all modules */
3904 /* blank module globbing: modname xor exclude_mod */
3905 if (!exclude_mod != !modname)
3911 * exclude_mod is set to trace everything but the given
3912 * module. If it is set and the module matches, then
3913 * return 0. If it is not set, and the module doesn't match
3914 * also return 0. Otherwise, check the function to see if
3917 if (!mod_matches == !exclude_mod)
3920 /* blank search means to match all funcs in the mod */
3925 return ftrace_match(str, func_g);
3929 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
3931 struct ftrace_page *pg;
3932 struct dyn_ftrace *rec;
3933 struct ftrace_glob func_g = { .type = MATCH_FULL };
3934 struct ftrace_glob mod_g = { .type = MATCH_FULL };
3935 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
3936 int exclude_mod = 0;
3939 int clear_filter = 0;
3942 func_g.type = filter_parse_regex(func, len, &func_g.search,
3944 func_g.len = strlen(func_g.search);
3948 mod_g.type = filter_parse_regex(mod, strlen(mod),
3949 &mod_g.search, &exclude_mod);
3950 mod_g.len = strlen(mod_g.search);
3953 mutex_lock(&ftrace_lock);
3955 if (unlikely(ftrace_disabled))
3958 if (func_g.type == MATCH_INDEX) {
3959 found = add_rec_by_index(hash, &func_g, clear_filter);
3963 do_for_each_ftrace_rec(pg, rec) {
3965 if (rec->flags & FTRACE_FL_DISABLED)
3968 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
3969 ret = enter_record(hash, rec, clear_filter);
3976 } while_for_each_ftrace_rec();
3978 mutex_unlock(&ftrace_lock);
3984 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
3986 return match_records(hash, buff, len, NULL);
3989 static void ftrace_ops_update_code(struct ftrace_ops *ops,
3990 struct ftrace_ops_hash *old_hash)
3992 struct ftrace_ops *op;
3994 if (!ftrace_enabled)
3997 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
3998 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4003 * If this is the shared global_ops filter, then we need to
4004 * check if there is another ops that shares it, is enabled.
4005 * If so, we still need to run the modify code.
4007 if (ops->func_hash != &global_ops.local_hash)
4010 do_for_each_ftrace_op(op, ftrace_ops_list) {
4011 if (op->func_hash == &global_ops.local_hash &&
4012 op->flags & FTRACE_OPS_FL_ENABLED) {
4013 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4014 /* Only need to do this once */
4017 } while_for_each_ftrace_op(op);
4020 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
4021 struct ftrace_hash **orig_hash,
4022 struct ftrace_hash *hash,
4025 struct ftrace_ops_hash old_hash_ops;
4026 struct ftrace_hash *old_hash;
4029 old_hash = *orig_hash;
4030 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4031 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4032 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4034 ftrace_ops_update_code(ops, &old_hash_ops);
4035 free_ftrace_hash_rcu(old_hash);
4040 static bool module_exists(const char *module)
4042 /* All modules have the symbol __this_module */
4043 static const char this_mod[] = "__this_module";
4044 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
4048 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
4050 if (n > sizeof(modname) - 1)
4053 val = module_kallsyms_lookup_name(modname);
4057 static int cache_mod(struct trace_array *tr,
4058 const char *func, char *module, int enable)
4060 struct ftrace_mod_load *ftrace_mod, *n;
4061 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4064 mutex_lock(&ftrace_lock);
4066 /* We do not cache inverse filters */
4067 if (func[0] == '!') {
4071 /* Look to remove this hash */
4072 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4073 if (strcmp(ftrace_mod->module, module) != 0)
4076 /* no func matches all */
4077 if (strcmp(func, "*") == 0 ||
4078 (ftrace_mod->func &&
4079 strcmp(ftrace_mod->func, func) == 0)) {
4081 free_ftrace_mod(ftrace_mod);
4089 /* We only care about modules that have not been loaded yet */
4090 if (module_exists(module))
4093 /* Save this string off, and execute it when the module is loaded */
4094 ret = ftrace_add_mod(tr, func, module, enable);
4096 mutex_unlock(&ftrace_lock);
4102 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4103 int reset, int enable);
4105 #ifdef CONFIG_MODULES
4106 static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4107 char *mod, bool enable)
4109 struct ftrace_mod_load *ftrace_mod, *n;
4110 struct ftrace_hash **orig_hash, *new_hash;
4111 LIST_HEAD(process_mods);
4115 mutex_lock(&ops->func_hash->regex_lock);
4118 orig_hash = &ops->func_hash->filter_hash;
4120 orig_hash = &ops->func_hash->notrace_hash;
4122 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4125 goto out; /* warn? */
4127 mutex_lock(&ftrace_lock);
4129 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4131 if (strcmp(ftrace_mod->module, mod) != 0)
4134 if (ftrace_mod->func)
4135 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4137 func = kstrdup("*", GFP_KERNEL);
4139 if (!func) /* warn? */
4142 list_del(&ftrace_mod->list);
4143 list_add(&ftrace_mod->list, &process_mods);
4145 /* Use the newly allocated func, as it may be "*" */
4146 kfree(ftrace_mod->func);
4147 ftrace_mod->func = func;
4150 mutex_unlock(&ftrace_lock);
4152 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4154 func = ftrace_mod->func;
4156 /* Grabs ftrace_lock, which is why we have this extra step */
4157 match_records(new_hash, func, strlen(func), mod);
4158 free_ftrace_mod(ftrace_mod);
4161 if (enable && list_empty(head))
4162 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4164 mutex_lock(&ftrace_lock);
4166 ret = ftrace_hash_move_and_update_ops(ops, orig_hash,
4168 mutex_unlock(&ftrace_lock);
4171 mutex_unlock(&ops->func_hash->regex_lock);
4173 free_ftrace_hash(new_hash);
4176 static void process_cached_mods(const char *mod_name)
4178 struct trace_array *tr;
4181 mod = kstrdup(mod_name, GFP_KERNEL);
4185 mutex_lock(&trace_types_lock);
4186 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4187 if (!list_empty(&tr->mod_trace))
4188 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4189 if (!list_empty(&tr->mod_notrace))
4190 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4192 mutex_unlock(&trace_types_lock);
4199 * We register the module command as a template to show others how
4200 * to register the a command as well.
4204 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4205 char *func_orig, char *cmd, char *module, int enable)
4210 /* match_records() modifies func, and we need the original */
4211 func = kstrdup(func_orig, GFP_KERNEL);
4216 * cmd == 'mod' because we only registered this func
4217 * for the 'mod' ftrace_func_command.
4218 * But if you register one func with multiple commands,
4219 * you can tell which command was used by the cmd
4222 ret = match_records(hash, func, strlen(func), module);
4226 return cache_mod(tr, func_orig, module, enable);
4232 static struct ftrace_func_command ftrace_mod_cmd = {
4234 .func = ftrace_mod_callback,
4237 static int __init ftrace_mod_cmd_init(void)
4239 return register_ftrace_command(&ftrace_mod_cmd);
4241 core_initcall(ftrace_mod_cmd_init);
4243 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4244 struct ftrace_ops *op, struct pt_regs *pt_regs)
4246 struct ftrace_probe_ops *probe_ops;
4247 struct ftrace_func_probe *probe;
4249 probe = container_of(op, struct ftrace_func_probe, ops);
4250 probe_ops = probe->probe_ops;
4253 * Disable preemption for these calls to prevent a RCU grace
4254 * period. This syncs the hash iteration and freeing of items
4255 * on the hash. rcu_read_lock is too dangerous here.
4257 preempt_disable_notrace();
4258 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4259 preempt_enable_notrace();
4262 struct ftrace_func_map {
4263 struct ftrace_func_entry entry;
4267 struct ftrace_func_mapper {
4268 struct ftrace_hash hash;
4272 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4274 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4276 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4278 struct ftrace_hash *hash;
4281 * The mapper is simply a ftrace_hash, but since the entries
4282 * in the hash are not ftrace_func_entry type, we define it
4283 * as a separate structure.
4285 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4286 return (struct ftrace_func_mapper *)hash;
4290 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4291 * @mapper: The mapper that has the ip maps
4292 * @ip: the instruction pointer to find the data for
4294 * Returns the data mapped to @ip if found otherwise NULL. The return
4295 * is actually the address of the mapper data pointer. The address is
4296 * returned for use cases where the data is no bigger than a long, and
4297 * the user can use the data pointer as its data instead of having to
4298 * allocate more memory for the reference.
4300 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4303 struct ftrace_func_entry *entry;
4304 struct ftrace_func_map *map;
4306 entry = ftrace_lookup_ip(&mapper->hash, ip);
4310 map = (struct ftrace_func_map *)entry;
4315 * ftrace_func_mapper_add_ip - Map some data to an ip
4316 * @mapper: The mapper that has the ip maps
4317 * @ip: The instruction pointer address to map @data to
4318 * @data: The data to map to @ip
4320 * Returns 0 on succes otherwise an error.
4322 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4323 unsigned long ip, void *data)
4325 struct ftrace_func_entry *entry;
4326 struct ftrace_func_map *map;
4328 entry = ftrace_lookup_ip(&mapper->hash, ip);
4332 map = kmalloc(sizeof(*map), GFP_KERNEL);
4339 __add_hash_entry(&mapper->hash, &map->entry);
4345 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4346 * @mapper: The mapper that has the ip maps
4347 * @ip: The instruction pointer address to remove the data from
4349 * Returns the data if it is found, otherwise NULL.
4350 * Note, if the data pointer is used as the data itself, (see
4351 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4352 * if the data pointer was set to zero.
4354 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4357 struct ftrace_func_entry *entry;
4358 struct ftrace_func_map *map;
4361 entry = ftrace_lookup_ip(&mapper->hash, ip);
4365 map = (struct ftrace_func_map *)entry;
4368 remove_hash_entry(&mapper->hash, entry);
4375 * free_ftrace_func_mapper - free a mapping of ips and data
4376 * @mapper: The mapper that has the ip maps
4377 * @free_func: A function to be called on each data item.
4379 * This is used to free the function mapper. The @free_func is optional
4380 * and can be used if the data needs to be freed as well.
4382 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4383 ftrace_mapper_func free_func)
4385 struct ftrace_func_entry *entry;
4386 struct ftrace_func_map *map;
4387 struct hlist_head *hhd;
4393 if (free_func && mapper->hash.count) {
4394 size = 1 << mapper->hash.size_bits;
4395 for (i = 0; i < size; i++) {
4396 hhd = &mapper->hash.buckets[i];
4397 hlist_for_each_entry(entry, hhd, hlist) {
4398 map = (struct ftrace_func_map *)entry;
4403 free_ftrace_hash(&mapper->hash);
4406 static void release_probe(struct ftrace_func_probe *probe)
4408 struct ftrace_probe_ops *probe_ops;
4410 mutex_lock(&ftrace_lock);
4412 WARN_ON(probe->ref <= 0);
4414 /* Subtract the ref that was used to protect this instance */
4418 probe_ops = probe->probe_ops;
4420 * Sending zero as ip tells probe_ops to free
4421 * the probe->data itself
4423 if (probe_ops->free)
4424 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4425 list_del(&probe->list);
4428 mutex_unlock(&ftrace_lock);
4431 static void acquire_probe_locked(struct ftrace_func_probe *probe)
4434 * Add one ref to keep it from being freed when releasing the
4435 * ftrace_lock mutex.
4441 register_ftrace_function_probe(char *glob, struct trace_array *tr,
4442 struct ftrace_probe_ops *probe_ops,
4445 struct ftrace_func_entry *entry;
4446 struct ftrace_func_probe *probe;
4447 struct ftrace_hash **orig_hash;
4448 struct ftrace_hash *old_hash;
4449 struct ftrace_hash *hash;
4458 /* We do not support '!' for function probes */
4459 if (WARN_ON(glob[0] == '!'))
4463 mutex_lock(&ftrace_lock);
4464 /* Check if the probe_ops is already registered */
4465 list_for_each_entry(probe, &tr->func_probes, list) {
4466 if (probe->probe_ops == probe_ops)
4469 if (&probe->list == &tr->func_probes) {
4470 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4472 mutex_unlock(&ftrace_lock);
4475 probe->probe_ops = probe_ops;
4476 probe->ops.func = function_trace_probe_call;
4478 ftrace_ops_init(&probe->ops);
4479 list_add(&probe->list, &tr->func_probes);
4482 acquire_probe_locked(probe);
4484 mutex_unlock(&ftrace_lock);
4487 * Note, there's a small window here that the func_hash->filter_hash
4488 * may be NULL or empty. Need to be carefule when reading the loop.
4490 mutex_lock(&probe->ops.func_hash->regex_lock);
4492 orig_hash = &probe->ops.func_hash->filter_hash;
4493 old_hash = *orig_hash;
4494 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4501 ret = ftrace_match_records(hash, glob, strlen(glob));
4503 /* Nothing found? */
4510 size = 1 << hash->size_bits;
4511 for (i = 0; i < size; i++) {
4512 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4513 if (ftrace_lookup_ip(old_hash, entry->ip))
4516 * The caller might want to do something special
4517 * for each function we find. We call the callback
4518 * to give the caller an opportunity to do so.
4520 if (probe_ops->init) {
4521 ret = probe_ops->init(probe_ops, tr,
4525 if (probe_ops->free && count)
4526 probe_ops->free(probe_ops, tr,
4536 mutex_lock(&ftrace_lock);
4539 /* Nothing was added? */
4544 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4549 /* One ref for each new function traced */
4550 probe->ref += count;
4552 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4553 ret = ftrace_startup(&probe->ops, 0);
4556 mutex_unlock(&ftrace_lock);
4561 mutex_unlock(&probe->ops.func_hash->regex_lock);
4562 free_ftrace_hash(hash);
4564 release_probe(probe);
4569 if (!probe_ops->free || !count)
4572 /* Failed to do the move, need to call the free functions */
4573 for (i = 0; i < size; i++) {
4574 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4575 if (ftrace_lookup_ip(old_hash, entry->ip))
4577 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4584 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4585 struct ftrace_probe_ops *probe_ops)
4587 struct ftrace_ops_hash old_hash_ops;
4588 struct ftrace_func_entry *entry;
4589 struct ftrace_func_probe *probe;
4590 struct ftrace_glob func_g;
4591 struct ftrace_hash **orig_hash;
4592 struct ftrace_hash *old_hash;
4593 struct ftrace_hash *hash = NULL;
4594 struct hlist_node *tmp;
4595 struct hlist_head hhd;
4596 char str[KSYM_SYMBOL_LEN];
4598 int i, ret = -ENODEV;
4601 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4602 func_g.search = NULL;
4606 func_g.type = filter_parse_regex(glob, strlen(glob),
4607 &func_g.search, ¬);
4608 func_g.len = strlen(func_g.search);
4610 /* we do not support '!' for function probes */
4615 mutex_lock(&ftrace_lock);
4616 /* Check if the probe_ops is already registered */
4617 list_for_each_entry(probe, &tr->func_probes, list) {
4618 if (probe->probe_ops == probe_ops)
4621 if (&probe->list == &tr->func_probes)
4622 goto err_unlock_ftrace;
4625 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4626 goto err_unlock_ftrace;
4628 acquire_probe_locked(probe);
4630 mutex_unlock(&ftrace_lock);
4632 mutex_lock(&probe->ops.func_hash->regex_lock);
4634 orig_hash = &probe->ops.func_hash->filter_hash;
4635 old_hash = *orig_hash;
4637 if (ftrace_hash_empty(old_hash))
4640 old_hash_ops.filter_hash = old_hash;
4641 /* Probes only have filters */
4642 old_hash_ops.notrace_hash = NULL;
4645 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4649 INIT_HLIST_HEAD(&hhd);
4651 size = 1 << hash->size_bits;
4652 for (i = 0; i < size; i++) {
4653 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4655 if (func_g.search) {
4656 kallsyms_lookup(entry->ip, NULL, NULL,
4658 if (!ftrace_match(str, &func_g))
4662 remove_hash_entry(hash, entry);
4663 hlist_add_head(&entry->hlist, &hhd);
4667 /* Nothing found? */
4673 mutex_lock(&ftrace_lock);
4675 WARN_ON(probe->ref < count);
4677 probe->ref -= count;
4679 if (ftrace_hash_empty(hash))
4680 ftrace_shutdown(&probe->ops, 0);
4682 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4685 /* still need to update the function call sites */
4686 if (ftrace_enabled && !ftrace_hash_empty(hash))
4687 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4691 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4692 hlist_del(&entry->hlist);
4693 if (probe_ops->free)
4694 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4697 mutex_unlock(&ftrace_lock);
4700 mutex_unlock(&probe->ops.func_hash->regex_lock);
4701 free_ftrace_hash(hash);
4703 release_probe(probe);
4708 mutex_unlock(&ftrace_lock);
4712 void clear_ftrace_function_probes(struct trace_array *tr)
4714 struct ftrace_func_probe *probe, *n;
4716 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4717 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
4720 static LIST_HEAD(ftrace_commands);
4721 static DEFINE_MUTEX(ftrace_cmd_mutex);
4724 * Currently we only register ftrace commands from __init, so mark this
4727 __init int register_ftrace_command(struct ftrace_func_command *cmd)
4729 struct ftrace_func_command *p;
4732 mutex_lock(&ftrace_cmd_mutex);
4733 list_for_each_entry(p, &ftrace_commands, list) {
4734 if (strcmp(cmd->name, p->name) == 0) {
4739 list_add(&cmd->list, &ftrace_commands);
4741 mutex_unlock(&ftrace_cmd_mutex);
4747 * Currently we only unregister ftrace commands from __init, so mark
4750 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4752 struct ftrace_func_command *p, *n;
4755 mutex_lock(&ftrace_cmd_mutex);
4756 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4757 if (strcmp(cmd->name, p->name) == 0) {
4759 list_del_init(&p->list);
4764 mutex_unlock(&ftrace_cmd_mutex);
4769 static int ftrace_process_regex(struct ftrace_iterator *iter,
4770 char *buff, int len, int enable)
4772 struct ftrace_hash *hash = iter->hash;
4773 struct trace_array *tr = iter->ops->private;
4774 char *func, *command, *next = buff;
4775 struct ftrace_func_command *p;
4778 func = strsep(&next, ":");
4781 ret = ftrace_match_records(hash, func, len);
4791 command = strsep(&next, ":");
4793 mutex_lock(&ftrace_cmd_mutex);
4794 list_for_each_entry(p, &ftrace_commands, list) {
4795 if (strcmp(p->name, command) == 0) {
4796 ret = p->func(tr, hash, func, command, next, enable);
4801 mutex_unlock(&ftrace_cmd_mutex);
4807 ftrace_regex_write(struct file *file, const char __user *ubuf,
4808 size_t cnt, loff_t *ppos, int enable)
4810 struct ftrace_iterator *iter;
4811 struct trace_parser *parser;
4817 if (file->f_mode & FMODE_READ) {
4818 struct seq_file *m = file->private_data;
4821 iter = file->private_data;
4823 if (unlikely(ftrace_disabled))
4826 /* iter->hash is a local copy, so we don't need regex_lock */
4828 parser = &iter->parser;
4829 read = trace_get_user(parser, ubuf, cnt, ppos);
4831 if (read >= 0 && trace_parser_loaded(parser) &&
4832 !trace_parser_cont(parser)) {
4833 ret = ftrace_process_regex(iter, parser->buffer,
4834 parser->idx, enable);
4835 trace_parser_clear(parser);
4846 ftrace_filter_write(struct file *file, const char __user *ubuf,
4847 size_t cnt, loff_t *ppos)
4849 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4853 ftrace_notrace_write(struct file *file, const char __user *ubuf,
4854 size_t cnt, loff_t *ppos)
4856 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4860 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4862 struct ftrace_func_entry *entry;
4864 if (!ftrace_location(ip))
4868 entry = ftrace_lookup_ip(hash, ip);
4871 free_hash_entry(hash, entry);
4875 return add_hash_entry(hash, ip);
4879 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4880 unsigned long ip, int remove, int reset, int enable)
4882 struct ftrace_hash **orig_hash;
4883 struct ftrace_hash *hash;
4886 if (unlikely(ftrace_disabled))
4889 mutex_lock(&ops->func_hash->regex_lock);
4892 orig_hash = &ops->func_hash->filter_hash;
4894 orig_hash = &ops->func_hash->notrace_hash;
4897 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4899 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4903 goto out_regex_unlock;
4906 if (buf && !ftrace_match_records(hash, buf, len)) {
4908 goto out_regex_unlock;
4911 ret = ftrace_match_addr(hash, ip, remove);
4913 goto out_regex_unlock;
4916 mutex_lock(&ftrace_lock);
4917 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
4918 mutex_unlock(&ftrace_lock);
4921 mutex_unlock(&ops->func_hash->regex_lock);
4923 free_ftrace_hash(hash);
4928 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
4929 int reset, int enable)
4931 return ftrace_set_hash(ops, NULL, 0, ip, remove, reset, enable);
4934 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
4936 struct ftrace_direct_func {
4937 struct list_head next;
4942 static LIST_HEAD(ftrace_direct_funcs);
4945 * ftrace_find_direct_func - test an address if it is a registered direct caller
4946 * @addr: The address of a registered direct caller
4948 * This searches to see if a ftrace direct caller has been registered
4949 * at a specific address, and if so, it returns a descriptor for it.
4951 * This can be used by architecture code to see if an address is
4952 * a direct caller (trampoline) attached to a fentry/mcount location.
4953 * This is useful for the function_graph tracer, as it may need to
4954 * do adjustments if it traced a location that also has a direct
4955 * trampoline attached to it.
4957 struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
4959 struct ftrace_direct_func *entry;
4962 /* May be called by fgraph trampoline (protected by rcu tasks) */
4963 list_for_each_entry_rcu(entry, &ftrace_direct_funcs, next) {
4964 if (entry->addr == addr) {
4976 * register_ftrace_direct - Call a custom trampoline directly
4977 * @ip: The address of the nop at the beginning of a function
4978 * @addr: The address of the trampoline to call at @ip
4980 * This is used to connect a direct call from the nop location (@ip)
4981 * at the start of ftrace traced functions. The location that it calls
4982 * (@addr) must be able to handle a direct call, and save the parameters
4983 * of the function being traced, and restore them (or inject new ones
4984 * if needed), before returning.
4988 * -EBUSY - Another direct function is already attached (there can be only one)
4989 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
4990 * -ENOMEM - There was an allocation failure.
4992 int register_ftrace_direct(unsigned long ip, unsigned long addr)
4994 struct ftrace_direct_func *direct;
4995 struct ftrace_func_entry *entry;
4996 struct ftrace_hash *free_hash = NULL;
4997 struct dyn_ftrace *rec;
5000 mutex_lock(&direct_mutex);
5002 /* See if there's a direct function at @ip already */
5003 if (ftrace_find_rec_direct(ip))
5007 rec = lookup_rec(ip, ip);
5012 * Check if the rec says it has a direct call but we didn't
5015 if (WARN_ON(rec->flags & FTRACE_FL_DIRECT))
5018 /* Make sure the ip points to the exact record */
5019 if (ip != rec->ip) {
5021 /* Need to check this ip for a direct. */
5022 if (ftrace_find_rec_direct(ip))
5027 if (ftrace_hash_empty(direct_functions) ||
5028 direct_functions->count > 2 * (1 << direct_functions->size_bits)) {
5029 struct ftrace_hash *new_hash;
5030 int size = ftrace_hash_empty(direct_functions) ? 0 :
5031 direct_functions->count + 1;
5036 new_hash = dup_hash(direct_functions, size);
5040 free_hash = direct_functions;
5041 direct_functions = new_hash;
5044 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
5048 direct = ftrace_find_direct_func(addr);
5050 direct = kmalloc(sizeof(*direct), GFP_KERNEL);
5055 direct->addr = addr;
5057 list_add_rcu(&direct->next, &ftrace_direct_funcs);
5058 ftrace_direct_func_count++;
5062 entry->direct = addr;
5063 __add_hash_entry(direct_functions, entry);
5065 ret = ftrace_set_filter_ip(&direct_ops, ip, 0, 0);
5067 remove_hash_entry(direct_functions, entry);
5069 if (!ret && !(direct_ops.flags & FTRACE_OPS_FL_ENABLED)) {
5070 ret = register_ftrace_function(&direct_ops);
5072 ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5077 if (!direct->count) {
5078 list_del_rcu(&direct->next);
5079 synchronize_rcu_tasks();
5082 free_ftrace_hash(free_hash);
5084 ftrace_direct_func_count--;
5090 mutex_unlock(&direct_mutex);
5093 synchronize_rcu_tasks();
5094 free_ftrace_hash(free_hash);
5099 EXPORT_SYMBOL_GPL(register_ftrace_direct);
5101 static struct ftrace_func_entry *find_direct_entry(unsigned long *ip,
5102 struct dyn_ftrace **recp)
5104 struct ftrace_func_entry *entry;
5105 struct dyn_ftrace *rec;
5107 rec = lookup_rec(*ip, *ip);
5111 entry = __ftrace_lookup_ip(direct_functions, rec->ip);
5113 WARN_ON(rec->flags & FTRACE_FL_DIRECT);
5117 WARN_ON(!(rec->flags & FTRACE_FL_DIRECT));
5119 /* Passed in ip just needs to be on the call site */
5128 int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
5130 struct ftrace_direct_func *direct;
5131 struct ftrace_func_entry *entry;
5134 mutex_lock(&direct_mutex);
5136 entry = find_direct_entry(&ip, NULL);
5140 if (direct_functions->count == 1)
5141 unregister_ftrace_function(&direct_ops);
5143 ret = ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5147 remove_hash_entry(direct_functions, entry);
5149 direct = ftrace_find_direct_func(addr);
5150 if (!WARN_ON(!direct)) {
5151 /* This is the good path (see the ! before WARN) */
5153 WARN_ON(direct->count < 0);
5154 if (!direct->count) {
5155 list_del_rcu(&direct->next);
5156 synchronize_rcu_tasks();
5158 ftrace_direct_func_count--;
5162 mutex_unlock(&direct_mutex);
5166 EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
5168 static struct ftrace_ops stub_ops = {
5169 .func = ftrace_stub,
5173 * ftrace_modify_direct_caller - modify ftrace nop directly
5174 * @entry: The ftrace hash entry of the direct helper for @rec
5175 * @rec: The record representing the function site to patch
5176 * @old_addr: The location that the site at @rec->ip currently calls
5177 * @new_addr: The location that the site at @rec->ip should call
5179 * An architecture may overwrite this function to optimize the
5180 * changing of the direct callback on an ftrace nop location.
5181 * This is called with the ftrace_lock mutex held, and no other
5182 * ftrace callbacks are on the associated record (@rec). Thus,
5183 * it is safe to modify the ftrace record, where it should be
5184 * currently calling @old_addr directly, to call @new_addr.
5186 * Safety checks should be made to make sure that the code at
5187 * @rec->ip is currently calling @old_addr. And this must
5188 * also update entry->direct to @new_addr.
5190 int __weak ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
5191 struct dyn_ftrace *rec,
5192 unsigned long old_addr,
5193 unsigned long new_addr)
5195 unsigned long ip = rec->ip;
5199 * The ftrace_lock was used to determine if the record
5200 * had more than one registered user to it. If it did,
5201 * we needed to prevent that from changing to do the quick
5202 * switch. But if it did not (only a direct caller was attached)
5203 * then this function is called. But this function can deal
5204 * with attached callers to the rec that we care about, and
5205 * since this function uses standard ftrace calls that take
5206 * the ftrace_lock mutex, we need to release it.
5208 mutex_unlock(&ftrace_lock);
5211 * By setting a stub function at the same address, we force
5212 * the code to call the iterator and the direct_ops helper.
5213 * This means that @ip does not call the direct call, and
5214 * we can simply modify it.
5216 ret = ftrace_set_filter_ip(&stub_ops, ip, 0, 0);
5220 ret = register_ftrace_function(&stub_ops);
5222 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5226 entry->direct = new_addr;
5229 * By removing the stub, we put back the direct call, calling
5232 unregister_ftrace_function(&stub_ops);
5233 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5236 mutex_lock(&ftrace_lock);
5242 * modify_ftrace_direct - Modify an existing direct call to call something else
5243 * @ip: The instruction pointer to modify
5244 * @old_addr: The address that the current @ip calls directly
5245 * @new_addr: The address that the @ip should call
5247 * This modifies a ftrace direct caller at an instruction pointer without
5248 * having to disable it first. The direct call will switch over to the
5249 * @new_addr without missing anything.
5251 * Returns: zero on success. Non zero on error, which includes:
5252 * -ENODEV : the @ip given has no direct caller attached
5253 * -EINVAL : the @old_addr does not match the current direct caller
5255 int modify_ftrace_direct(unsigned long ip,
5256 unsigned long old_addr, unsigned long new_addr)
5258 struct ftrace_func_entry *entry;
5259 struct dyn_ftrace *rec;
5262 mutex_lock(&direct_mutex);
5264 mutex_lock(&ftrace_lock);
5265 entry = find_direct_entry(&ip, &rec);
5270 if (entry->direct != old_addr)
5274 * If there's no other ftrace callback on the rec->ip location,
5275 * then it can be changed directly by the architecture.
5276 * If there is another caller, then we just need to change the
5277 * direct caller helper to point to @new_addr.
5279 if (ftrace_rec_count(rec) == 1) {
5280 ret = ftrace_modify_direct_caller(entry, rec, old_addr, new_addr);
5282 entry->direct = new_addr;
5287 mutex_unlock(&ftrace_lock);
5288 mutex_unlock(&direct_mutex);
5291 EXPORT_SYMBOL_GPL(modify_ftrace_direct);
5292 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
5295 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
5296 * @ops - the ops to set the filter with
5297 * @ip - the address to add to or remove from the filter.
5298 * @remove - non zero to remove the ip from the filter
5299 * @reset - non zero to reset all filters before applying this filter.
5301 * Filters denote which functions should be enabled when tracing is enabled
5302 * If @ip is NULL, it failes to update filter.
5304 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
5305 int remove, int reset)
5307 ftrace_ops_init(ops);
5308 return ftrace_set_addr(ops, ip, remove, reset, 1);
5310 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
5313 * ftrace_ops_set_global_filter - setup ops to use global filters
5314 * @ops - the ops which will use the global filters
5316 * ftrace users who need global function trace filtering should call this.
5317 * It can set the global filter only if ops were not initialized before.
5319 void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
5321 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
5324 ftrace_ops_init(ops);
5325 ops->func_hash = &global_ops.local_hash;
5327 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
5330 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
5331 int reset, int enable)
5333 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
5337 * ftrace_set_filter - set a function to filter on in ftrace
5338 * @ops - the ops to set the filter with
5339 * @buf - the string that holds the function filter text.
5340 * @len - the length of the string.
5341 * @reset - non zero to reset all filters before applying this filter.
5343 * Filters denote which functions should be enabled when tracing is enabled.
5344 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5346 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
5349 ftrace_ops_init(ops);
5350 return ftrace_set_regex(ops, buf, len, reset, 1);
5352 EXPORT_SYMBOL_GPL(ftrace_set_filter);
5355 * ftrace_set_notrace - set a function to not trace in ftrace
5356 * @ops - the ops to set the notrace filter with
5357 * @buf - the string that holds the function notrace text.
5358 * @len - the length of the string.
5359 * @reset - non zero to reset all filters before applying this filter.
5361 * Notrace Filters denote which functions should not be enabled when tracing
5362 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5365 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
5368 ftrace_ops_init(ops);
5369 return ftrace_set_regex(ops, buf, len, reset, 0);
5371 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
5373 * ftrace_set_global_filter - set a function to filter on with global tracers
5374 * @buf - the string that holds the function filter text.
5375 * @len - the length of the string.
5376 * @reset - non zero to reset all filters before applying this filter.
5378 * Filters denote which functions should be enabled when tracing is enabled.
5379 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5381 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
5383 ftrace_set_regex(&global_ops, buf, len, reset, 1);
5385 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
5388 * ftrace_set_global_notrace - set a function to not trace with global tracers
5389 * @buf - the string that holds the function notrace text.
5390 * @len - the length of the string.
5391 * @reset - non zero to reset all filters before applying this filter.
5393 * Notrace Filters denote which functions should not be enabled when tracing
5394 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5397 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
5399 ftrace_set_regex(&global_ops, buf, len, reset, 0);
5401 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
5404 * command line interface to allow users to set filters on boot up.
5406 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
5407 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5408 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
5410 /* Used by function selftest to not test if filter is set */
5411 bool ftrace_filter_param __initdata;
5413 static int __init set_ftrace_notrace(char *str)
5415 ftrace_filter_param = true;
5416 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
5419 __setup("ftrace_notrace=", set_ftrace_notrace);
5421 static int __init set_ftrace_filter(char *str)
5423 ftrace_filter_param = true;
5424 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
5427 __setup("ftrace_filter=", set_ftrace_filter);
5429 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5430 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
5431 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5432 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
5434 static int __init set_graph_function(char *str)
5436 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
5439 __setup("ftrace_graph_filter=", set_graph_function);
5441 static int __init set_graph_notrace_function(char *str)
5443 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
5446 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
5448 static int __init set_graph_max_depth_function(char *str)
5452 fgraph_max_depth = simple_strtoul(str, NULL, 0);
5455 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
5457 static void __init set_ftrace_early_graph(char *buf, int enable)
5461 struct ftrace_hash *hash;
5463 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5464 if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
5468 func = strsep(&buf, ",");
5469 /* we allow only one expression at a time */
5470 ret = ftrace_graph_set_hash(hash, func);
5472 printk(KERN_DEBUG "ftrace: function %s not "
5473 "traceable\n", func);
5477 ftrace_graph_hash = hash;
5479 ftrace_graph_notrace_hash = hash;
5481 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5484 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
5488 ftrace_ops_init(ops);
5491 func = strsep(&buf, ",");
5492 ftrace_set_regex(ops, func, strlen(func), 0, enable);
5496 static void __init set_ftrace_early_filters(void)
5498 if (ftrace_filter_buf[0])
5499 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
5500 if (ftrace_notrace_buf[0])
5501 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
5502 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5503 if (ftrace_graph_buf[0])
5504 set_ftrace_early_graph(ftrace_graph_buf, 1);
5505 if (ftrace_graph_notrace_buf[0])
5506 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
5507 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5510 int ftrace_regex_release(struct inode *inode, struct file *file)
5512 struct seq_file *m = (struct seq_file *)file->private_data;
5513 struct ftrace_iterator *iter;
5514 struct ftrace_hash **orig_hash;
5515 struct trace_parser *parser;
5519 if (file->f_mode & FMODE_READ) {
5521 seq_release(inode, file);
5523 iter = file->private_data;
5525 parser = &iter->parser;
5526 if (trace_parser_loaded(parser)) {
5527 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
5530 trace_parser_put(parser);
5532 mutex_lock(&iter->ops->func_hash->regex_lock);
5534 if (file->f_mode & FMODE_WRITE) {
5535 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5538 orig_hash = &iter->ops->func_hash->filter_hash;
5539 if (iter->tr && !list_empty(&iter->tr->mod_trace))
5540 iter->hash->flags |= FTRACE_HASH_FL_MOD;
5542 orig_hash = &iter->ops->func_hash->notrace_hash;
5544 mutex_lock(&ftrace_lock);
5545 ret = ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5546 iter->hash, filter_hash);
5547 mutex_unlock(&ftrace_lock);
5549 /* For read only, the hash is the ops hash */
5553 mutex_unlock(&iter->ops->func_hash->regex_lock);
5554 free_ftrace_hash(iter->hash);
5556 trace_array_put(iter->tr);
5562 static const struct file_operations ftrace_avail_fops = {
5563 .open = ftrace_avail_open,
5565 .llseek = seq_lseek,
5566 .release = seq_release_private,
5569 static const struct file_operations ftrace_enabled_fops = {
5570 .open = ftrace_enabled_open,
5572 .llseek = seq_lseek,
5573 .release = seq_release_private,
5576 static const struct file_operations ftrace_filter_fops = {
5577 .open = ftrace_filter_open,
5579 .write = ftrace_filter_write,
5580 .llseek = tracing_lseek,
5581 .release = ftrace_regex_release,
5584 static const struct file_operations ftrace_notrace_fops = {
5585 .open = ftrace_notrace_open,
5587 .write = ftrace_notrace_write,
5588 .llseek = tracing_lseek,
5589 .release = ftrace_regex_release,
5592 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5594 static DEFINE_MUTEX(graph_lock);
5596 struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
5597 struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
5599 enum graph_filter_type {
5600 GRAPH_FILTER_NOTRACE = 0,
5601 GRAPH_FILTER_FUNCTION,
5604 #define FTRACE_GRAPH_EMPTY ((void *)1)
5606 struct ftrace_graph_data {
5607 struct ftrace_hash *hash;
5608 struct ftrace_func_entry *entry;
5609 int idx; /* for hash table iteration */
5610 enum graph_filter_type type;
5611 struct ftrace_hash *new_hash;
5612 const struct seq_operations *seq_ops;
5613 struct trace_parser parser;
5617 __g_next(struct seq_file *m, loff_t *pos)
5619 struct ftrace_graph_data *fgd = m->private;
5620 struct ftrace_func_entry *entry = fgd->entry;
5621 struct hlist_head *head;
5622 int i, idx = fgd->idx;
5624 if (*pos >= fgd->hash->count)
5628 hlist_for_each_entry_continue(entry, hlist) {
5636 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
5637 head = &fgd->hash->buckets[i];
5638 hlist_for_each_entry(entry, head, hlist) {
5648 g_next(struct seq_file *m, void *v, loff_t *pos)
5651 return __g_next(m, pos);
5654 static void *g_start(struct seq_file *m, loff_t *pos)
5656 struct ftrace_graph_data *fgd = m->private;
5658 mutex_lock(&graph_lock);
5660 if (fgd->type == GRAPH_FILTER_FUNCTION)
5661 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5662 lockdep_is_held(&graph_lock));
5664 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5665 lockdep_is_held(&graph_lock));
5667 /* Nothing, tell g_show to print all functions are enabled */
5668 if (ftrace_hash_empty(fgd->hash) && !*pos)
5669 return FTRACE_GRAPH_EMPTY;
5673 return __g_next(m, pos);
5676 static void g_stop(struct seq_file *m, void *p)
5678 mutex_unlock(&graph_lock);
5681 static int g_show(struct seq_file *m, void *v)
5683 struct ftrace_func_entry *entry = v;
5688 if (entry == FTRACE_GRAPH_EMPTY) {
5689 struct ftrace_graph_data *fgd = m->private;
5691 if (fgd->type == GRAPH_FILTER_FUNCTION)
5692 seq_puts(m, "#### all functions enabled ####\n");
5694 seq_puts(m, "#### no functions disabled ####\n");
5698 seq_printf(m, "%ps\n", (void *)entry->ip);
5703 static const struct seq_operations ftrace_graph_seq_ops = {
5711 __ftrace_graph_open(struct inode *inode, struct file *file,
5712 struct ftrace_graph_data *fgd)
5715 struct ftrace_hash *new_hash = NULL;
5717 ret = security_locked_down(LOCKDOWN_TRACEFS);
5721 if (file->f_mode & FMODE_WRITE) {
5722 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
5724 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
5727 if (file->f_flags & O_TRUNC)
5728 new_hash = alloc_ftrace_hash(size_bits);
5730 new_hash = alloc_and_copy_ftrace_hash(size_bits,
5738 if (file->f_mode & FMODE_READ) {
5739 ret = seq_open(file, &ftrace_graph_seq_ops);
5741 struct seq_file *m = file->private_data;
5745 free_ftrace_hash(new_hash);
5749 file->private_data = fgd;
5752 if (ret < 0 && file->f_mode & FMODE_WRITE)
5753 trace_parser_put(&fgd->parser);
5755 fgd->new_hash = new_hash;
5758 * All uses of fgd->hash must be taken with the graph_lock
5759 * held. The graph_lock is going to be released, so force
5760 * fgd->hash to be reinitialized when it is taken again.
5768 ftrace_graph_open(struct inode *inode, struct file *file)
5770 struct ftrace_graph_data *fgd;
5773 if (unlikely(ftrace_disabled))
5776 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5780 mutex_lock(&graph_lock);
5782 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5783 lockdep_is_held(&graph_lock));
5784 fgd->type = GRAPH_FILTER_FUNCTION;
5785 fgd->seq_ops = &ftrace_graph_seq_ops;
5787 ret = __ftrace_graph_open(inode, file, fgd);
5791 mutex_unlock(&graph_lock);
5796 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
5798 struct ftrace_graph_data *fgd;
5801 if (unlikely(ftrace_disabled))
5804 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5808 mutex_lock(&graph_lock);
5810 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5811 lockdep_is_held(&graph_lock));
5812 fgd->type = GRAPH_FILTER_NOTRACE;
5813 fgd->seq_ops = &ftrace_graph_seq_ops;
5815 ret = __ftrace_graph_open(inode, file, fgd);
5819 mutex_unlock(&graph_lock);
5824 ftrace_graph_release(struct inode *inode, struct file *file)
5826 struct ftrace_graph_data *fgd;
5827 struct ftrace_hash *old_hash, *new_hash;
5828 struct trace_parser *parser;
5831 if (file->f_mode & FMODE_READ) {
5832 struct seq_file *m = file->private_data;
5835 seq_release(inode, file);
5837 fgd = file->private_data;
5841 if (file->f_mode & FMODE_WRITE) {
5843 parser = &fgd->parser;
5845 if (trace_parser_loaded((parser))) {
5846 ret = ftrace_graph_set_hash(fgd->new_hash,
5850 trace_parser_put(parser);
5852 new_hash = __ftrace_hash_move(fgd->new_hash);
5858 mutex_lock(&graph_lock);
5860 if (fgd->type == GRAPH_FILTER_FUNCTION) {
5861 old_hash = rcu_dereference_protected(ftrace_graph_hash,
5862 lockdep_is_held(&graph_lock));
5863 rcu_assign_pointer(ftrace_graph_hash, new_hash);
5865 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5866 lockdep_is_held(&graph_lock));
5867 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
5870 mutex_unlock(&graph_lock);
5873 * We need to do a hard force of sched synchronization.
5874 * This is because we use preempt_disable() to do RCU, but
5875 * the function tracers can be called where RCU is not watching
5876 * (like before user_exit()). We can not rely on the RCU
5877 * infrastructure to do the synchronization, thus we must do it
5880 schedule_on_each_cpu(ftrace_sync);
5882 free_ftrace_hash(old_hash);
5886 free_ftrace_hash(fgd->new_hash);
5893 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
5895 struct ftrace_glob func_g;
5896 struct dyn_ftrace *rec;
5897 struct ftrace_page *pg;
5898 struct ftrace_func_entry *entry;
5903 func_g.type = filter_parse_regex(buffer, strlen(buffer),
5904 &func_g.search, ¬);
5906 func_g.len = strlen(func_g.search);
5908 mutex_lock(&ftrace_lock);
5910 if (unlikely(ftrace_disabled)) {
5911 mutex_unlock(&ftrace_lock);
5915 do_for_each_ftrace_rec(pg, rec) {
5917 if (rec->flags & FTRACE_FL_DISABLED)
5920 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
5921 entry = ftrace_lookup_ip(hash, rec->ip);
5928 if (add_hash_entry(hash, rec->ip) < 0)
5932 free_hash_entry(hash, entry);
5937 } while_for_each_ftrace_rec();
5939 mutex_unlock(&ftrace_lock);
5948 ftrace_graph_write(struct file *file, const char __user *ubuf,
5949 size_t cnt, loff_t *ppos)
5951 ssize_t read, ret = 0;
5952 struct ftrace_graph_data *fgd = file->private_data;
5953 struct trace_parser *parser;
5958 /* Read mode uses seq functions */
5959 if (file->f_mode & FMODE_READ) {
5960 struct seq_file *m = file->private_data;
5964 parser = &fgd->parser;
5966 read = trace_get_user(parser, ubuf, cnt, ppos);
5968 if (read >= 0 && trace_parser_loaded(parser) &&
5969 !trace_parser_cont(parser)) {
5971 ret = ftrace_graph_set_hash(fgd->new_hash,
5973 trace_parser_clear(parser);
5982 static const struct file_operations ftrace_graph_fops = {
5983 .open = ftrace_graph_open,
5985 .write = ftrace_graph_write,
5986 .llseek = tracing_lseek,
5987 .release = ftrace_graph_release,
5990 static const struct file_operations ftrace_graph_notrace_fops = {
5991 .open = ftrace_graph_notrace_open,
5993 .write = ftrace_graph_write,
5994 .llseek = tracing_lseek,
5995 .release = ftrace_graph_release,
5997 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5999 void ftrace_create_filter_files(struct ftrace_ops *ops,
6000 struct dentry *parent)
6003 trace_create_file("set_ftrace_filter", 0644, parent,
6004 ops, &ftrace_filter_fops);
6006 trace_create_file("set_ftrace_notrace", 0644, parent,
6007 ops, &ftrace_notrace_fops);
6011 * The name "destroy_filter_files" is really a misnomer. Although
6012 * in the future, it may actually delete the files, but this is
6013 * really intended to make sure the ops passed in are disabled
6014 * and that when this function returns, the caller is free to
6017 * The "destroy" name is only to match the "create" name that this
6018 * should be paired with.
6020 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
6022 mutex_lock(&ftrace_lock);
6023 if (ops->flags & FTRACE_OPS_FL_ENABLED)
6024 ftrace_shutdown(ops, 0);
6025 ops->flags |= FTRACE_OPS_FL_DELETED;
6026 ftrace_free_filter(ops);
6027 mutex_unlock(&ftrace_lock);
6030 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
6033 trace_create_file("available_filter_functions", 0444,
6034 d_tracer, NULL, &ftrace_avail_fops);
6036 trace_create_file("enabled_functions", 0444,
6037 d_tracer, NULL, &ftrace_enabled_fops);
6039 ftrace_create_filter_files(&global_ops, d_tracer);
6041 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
6042 trace_create_file("set_graph_function", 0644, d_tracer,
6044 &ftrace_graph_fops);
6045 trace_create_file("set_graph_notrace", 0644, d_tracer,
6047 &ftrace_graph_notrace_fops);
6048 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6053 static int ftrace_cmp_ips(const void *a, const void *b)
6055 const unsigned long *ipa = a;
6056 const unsigned long *ipb = b;
6065 static int ftrace_process_locs(struct module *mod,
6066 unsigned long *start,
6069 struct ftrace_page *start_pg;
6070 struct ftrace_page *pg;
6071 struct dyn_ftrace *rec;
6072 unsigned long count;
6075 unsigned long flags = 0; /* Shut up gcc */
6078 count = end - start;
6083 sort(start, count, sizeof(*start),
6084 ftrace_cmp_ips, NULL);
6086 start_pg = ftrace_allocate_pages(count);
6090 mutex_lock(&ftrace_lock);
6093 * Core and each module needs their own pages, as
6094 * modules will free them when they are removed.
6095 * Force a new page to be allocated for modules.
6098 WARN_ON(ftrace_pages || ftrace_pages_start);
6099 /* First initialization */
6100 ftrace_pages = ftrace_pages_start = start_pg;
6105 if (WARN_ON(ftrace_pages->next)) {
6106 /* Hmm, we have free pages? */
6107 while (ftrace_pages->next)
6108 ftrace_pages = ftrace_pages->next;
6111 ftrace_pages->next = start_pg;
6117 addr = ftrace_call_adjust(*p++);
6119 * Some architecture linkers will pad between
6120 * the different mcount_loc sections of different
6121 * object files to satisfy alignments.
6122 * Skip any NULL pointers.
6127 if (pg->index == pg->size) {
6128 /* We should have allocated enough */
6129 if (WARN_ON(!pg->next))
6134 rec = &pg->records[pg->index++];
6138 /* We should have used all pages */
6141 /* Assign the last page to ftrace_pages */
6145 * We only need to disable interrupts on start up
6146 * because we are modifying code that an interrupt
6147 * may execute, and the modification is not atomic.
6148 * But for modules, nothing runs the code we modify
6149 * until we are finished with it, and there's no
6150 * reason to cause large interrupt latencies while we do it.
6153 local_irq_save(flags);
6154 ftrace_update_code(mod, start_pg);
6156 local_irq_restore(flags);
6159 mutex_unlock(&ftrace_lock);
6164 struct ftrace_mod_func {
6165 struct list_head list;
6171 struct ftrace_mod_map {
6172 struct rcu_head rcu;
6173 struct list_head list;
6175 unsigned long start_addr;
6176 unsigned long end_addr;
6177 struct list_head funcs;
6178 unsigned int num_funcs;
6181 #ifdef CONFIG_MODULES
6183 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
6185 static LIST_HEAD(ftrace_mod_maps);
6187 static int referenced_filters(struct dyn_ftrace *rec)
6189 struct ftrace_ops *ops;
6192 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
6193 if (ops_references_rec(ops, rec))
6201 clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
6203 struct ftrace_func_entry *entry;
6204 struct dyn_ftrace *rec;
6207 if (ftrace_hash_empty(hash))
6210 for (i = 0; i < pg->index; i++) {
6211 rec = &pg->records[i];
6212 entry = __ftrace_lookup_ip(hash, rec->ip);
6214 * Do not allow this rec to match again.
6215 * Yeah, it may waste some memory, but will be removed
6216 * if/when the hash is modified again.
6223 /* Clear any records from hashs */
6224 static void clear_mod_from_hashes(struct ftrace_page *pg)
6226 struct trace_array *tr;
6228 mutex_lock(&trace_types_lock);
6229 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6230 if (!tr->ops || !tr->ops->func_hash)
6232 mutex_lock(&tr->ops->func_hash->regex_lock);
6233 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
6234 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
6235 mutex_unlock(&tr->ops->func_hash->regex_lock);
6237 mutex_unlock(&trace_types_lock);
6240 static void ftrace_free_mod_map(struct rcu_head *rcu)
6242 struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
6243 struct ftrace_mod_func *mod_func;
6244 struct ftrace_mod_func *n;
6246 /* All the contents of mod_map are now not visible to readers */
6247 list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
6248 kfree(mod_func->name);
6249 list_del(&mod_func->list);
6256 void ftrace_release_mod(struct module *mod)
6258 struct ftrace_mod_map *mod_map;
6259 struct ftrace_mod_map *n;
6260 struct dyn_ftrace *rec;
6261 struct ftrace_page **last_pg;
6262 struct ftrace_page *tmp_page = NULL;
6263 struct ftrace_page *pg;
6266 mutex_lock(&ftrace_lock);
6268 if (ftrace_disabled)
6271 list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
6272 if (mod_map->mod == mod) {
6273 list_del_rcu(&mod_map->list);
6274 call_rcu(&mod_map->rcu, ftrace_free_mod_map);
6280 * Each module has its own ftrace_pages, remove
6281 * them from the list.
6283 last_pg = &ftrace_pages_start;
6284 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
6285 rec = &pg->records[0];
6286 if (within_module_core(rec->ip, mod) ||
6287 within_module_init(rec->ip, mod)) {
6289 * As core pages are first, the first
6290 * page should never be a module page.
6292 if (WARN_ON(pg == ftrace_pages_start))
6295 /* Check if we are deleting the last page */
6296 if (pg == ftrace_pages)
6297 ftrace_pages = next_to_ftrace_page(last_pg);
6299 ftrace_update_tot_cnt -= pg->index;
6300 *last_pg = pg->next;
6302 pg->next = tmp_page;
6305 last_pg = &pg->next;
6308 mutex_unlock(&ftrace_lock);
6310 for (pg = tmp_page; pg; pg = tmp_page) {
6312 /* Needs to be called outside of ftrace_lock */
6313 clear_mod_from_hashes(pg);
6315 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
6316 free_pages((unsigned long)pg->records, order);
6317 tmp_page = pg->next;
6319 ftrace_number_of_pages -= 1 << order;
6320 ftrace_number_of_groups--;
6324 void ftrace_module_enable(struct module *mod)
6326 struct dyn_ftrace *rec;
6327 struct ftrace_page *pg;
6329 mutex_lock(&ftrace_lock);
6331 if (ftrace_disabled)
6335 * If the tracing is enabled, go ahead and enable the record.
6337 * The reason not to enable the record immediately is the
6338 * inherent check of ftrace_make_nop/ftrace_make_call for
6339 * correct previous instructions. Making first the NOP
6340 * conversion puts the module to the correct state, thus
6341 * passing the ftrace_make_call check.
6343 * We also delay this to after the module code already set the
6344 * text to read-only, as we now need to set it back to read-write
6345 * so that we can modify the text.
6347 if (ftrace_start_up)
6348 ftrace_arch_code_modify_prepare();
6350 do_for_each_ftrace_rec(pg, rec) {
6353 * do_for_each_ftrace_rec() is a double loop.
6354 * module text shares the pg. If a record is
6355 * not part of this module, then skip this pg,
6356 * which the "break" will do.
6358 if (!within_module_core(rec->ip, mod) &&
6359 !within_module_init(rec->ip, mod))
6365 * When adding a module, we need to check if tracers are
6366 * currently enabled and if they are, and can trace this record,
6367 * we need to enable the module functions as well as update the
6368 * reference counts for those function records.
6370 if (ftrace_start_up)
6371 cnt += referenced_filters(rec);
6373 /* This clears FTRACE_FL_DISABLED */
6376 if (ftrace_start_up && cnt) {
6377 int failed = __ftrace_replace_code(rec, 1);
6379 ftrace_bug(failed, rec);
6384 } while_for_each_ftrace_rec();
6387 if (ftrace_start_up)
6388 ftrace_arch_code_modify_post_process();
6391 mutex_unlock(&ftrace_lock);
6393 process_cached_mods(mod->name);
6396 void ftrace_module_init(struct module *mod)
6398 if (ftrace_disabled || !mod->num_ftrace_callsites)
6401 ftrace_process_locs(mod, mod->ftrace_callsites,
6402 mod->ftrace_callsites + mod->num_ftrace_callsites);
6405 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6406 struct dyn_ftrace *rec)
6408 struct ftrace_mod_func *mod_func;
6409 unsigned long symsize;
6410 unsigned long offset;
6411 char str[KSYM_SYMBOL_LEN];
6415 ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
6419 mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
6423 mod_func->name = kstrdup(str, GFP_KERNEL);
6424 if (!mod_func->name) {
6429 mod_func->ip = rec->ip - offset;
6430 mod_func->size = symsize;
6432 mod_map->num_funcs++;
6434 list_add_rcu(&mod_func->list, &mod_map->funcs);
6437 static struct ftrace_mod_map *
6438 allocate_ftrace_mod_map(struct module *mod,
6439 unsigned long start, unsigned long end)
6441 struct ftrace_mod_map *mod_map;
6443 mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
6448 mod_map->start_addr = start;
6449 mod_map->end_addr = end;
6450 mod_map->num_funcs = 0;
6452 INIT_LIST_HEAD_RCU(&mod_map->funcs);
6454 list_add_rcu(&mod_map->list, &ftrace_mod_maps);
6460 ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
6461 unsigned long addr, unsigned long *size,
6462 unsigned long *off, char *sym)
6464 struct ftrace_mod_func *found_func = NULL;
6465 struct ftrace_mod_func *mod_func;
6467 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6468 if (addr >= mod_func->ip &&
6469 addr < mod_func->ip + mod_func->size) {
6470 found_func = mod_func;
6477 *size = found_func->size;
6479 *off = addr - found_func->ip;
6481 strlcpy(sym, found_func->name, KSYM_NAME_LEN);
6483 return found_func->name;
6490 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
6491 unsigned long *off, char **modname, char *sym)
6493 struct ftrace_mod_map *mod_map;
6494 const char *ret = NULL;
6496 /* mod_map is freed via call_rcu() */
6498 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6499 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
6502 *modname = mod_map->mod->name;
6511 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
6512 char *type, char *name,
6513 char *module_name, int *exported)
6515 struct ftrace_mod_map *mod_map;
6516 struct ftrace_mod_func *mod_func;
6519 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6521 if (symnum >= mod_map->num_funcs) {
6522 symnum -= mod_map->num_funcs;
6526 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6532 *value = mod_func->ip;
6534 strlcpy(name, mod_func->name, KSYM_NAME_LEN);
6535 strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
6548 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6549 struct dyn_ftrace *rec) { }
6550 static inline struct ftrace_mod_map *
6551 allocate_ftrace_mod_map(struct module *mod,
6552 unsigned long start, unsigned long end)
6556 #endif /* CONFIG_MODULES */
6558 struct ftrace_init_func {
6559 struct list_head list;
6563 /* Clear any init ips from hashes */
6565 clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
6567 struct ftrace_func_entry *entry;
6569 entry = ftrace_lookup_ip(hash, func->ip);
6571 * Do not allow this rec to match again.
6572 * Yeah, it may waste some memory, but will be removed
6573 * if/when the hash is modified again.
6580 clear_func_from_hashes(struct ftrace_init_func *func)
6582 struct trace_array *tr;
6584 mutex_lock(&trace_types_lock);
6585 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6586 if (!tr->ops || !tr->ops->func_hash)
6588 mutex_lock(&tr->ops->func_hash->regex_lock);
6589 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
6590 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
6591 mutex_unlock(&tr->ops->func_hash->regex_lock);
6593 mutex_unlock(&trace_types_lock);
6596 static void add_to_clear_hash_list(struct list_head *clear_list,
6597 struct dyn_ftrace *rec)
6599 struct ftrace_init_func *func;
6601 func = kmalloc(sizeof(*func), GFP_KERNEL);
6603 MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
6608 list_add(&func->list, clear_list);
6611 void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
6613 unsigned long start = (unsigned long)(start_ptr);
6614 unsigned long end = (unsigned long)(end_ptr);
6615 struct ftrace_page **last_pg = &ftrace_pages_start;
6616 struct ftrace_page *pg;
6617 struct dyn_ftrace *rec;
6618 struct dyn_ftrace key;
6619 struct ftrace_mod_map *mod_map = NULL;
6620 struct ftrace_init_func *func, *func_next;
6621 struct list_head clear_hash;
6624 INIT_LIST_HEAD(&clear_hash);
6627 key.flags = end; /* overload flags, as it is unsigned long */
6629 mutex_lock(&ftrace_lock);
6632 * If we are freeing module init memory, then check if
6633 * any tracer is active. If so, we need to save a mapping of
6634 * the module functions being freed with the address.
6636 if (mod && ftrace_ops_list != &ftrace_list_end)
6637 mod_map = allocate_ftrace_mod_map(mod, start, end);
6639 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
6640 if (end < pg->records[0].ip ||
6641 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
6644 rec = bsearch(&key, pg->records, pg->index,
6645 sizeof(struct dyn_ftrace),
6650 /* rec will be cleared from hashes after ftrace_lock unlock */
6651 add_to_clear_hash_list(&clear_hash, rec);
6654 save_ftrace_mod_rec(mod_map, rec);
6657 ftrace_update_tot_cnt--;
6659 *last_pg = pg->next;
6660 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
6661 free_pages((unsigned long)pg->records, order);
6662 ftrace_number_of_pages -= 1 << order;
6663 ftrace_number_of_groups--;
6665 pg = container_of(last_pg, struct ftrace_page, next);
6670 memmove(rec, rec + 1,
6671 (pg->index - (rec - pg->records)) * sizeof(*rec));
6672 /* More than one function may be in this block */
6675 mutex_unlock(&ftrace_lock);
6677 list_for_each_entry_safe(func, func_next, &clear_hash, list) {
6678 clear_func_from_hashes(func);
6683 void __init ftrace_free_init_mem(void)
6685 void *start = (void *)(&__init_begin);
6686 void *end = (void *)(&__init_end);
6688 ftrace_free_mem(NULL, start, end);
6691 void __init ftrace_init(void)
6693 extern unsigned long __start_mcount_loc[];
6694 extern unsigned long __stop_mcount_loc[];
6695 unsigned long count, flags;
6698 local_irq_save(flags);
6699 ret = ftrace_dyn_arch_init();
6700 local_irq_restore(flags);
6704 count = __stop_mcount_loc - __start_mcount_loc;
6706 pr_info("ftrace: No functions to be traced?\n");
6710 pr_info("ftrace: allocating %ld entries in %ld pages\n",
6711 count, count / ENTRIES_PER_PAGE + 1);
6713 last_ftrace_enabled = ftrace_enabled = 1;
6715 ret = ftrace_process_locs(NULL,
6719 pr_info("ftrace: allocated %ld pages with %ld groups\n",
6720 ftrace_number_of_pages, ftrace_number_of_groups);
6722 set_ftrace_early_filters();
6726 ftrace_disabled = 1;
6729 /* Do nothing if arch does not support this */
6730 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
6734 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6736 arch_ftrace_update_trampoline(ops);
6739 void ftrace_init_trace_array(struct trace_array *tr)
6741 INIT_LIST_HEAD(&tr->func_probes);
6742 INIT_LIST_HEAD(&tr->mod_trace);
6743 INIT_LIST_HEAD(&tr->mod_notrace);
6747 struct ftrace_ops global_ops = {
6748 .func = ftrace_stub,
6749 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
6750 FTRACE_OPS_FL_INITIALIZED |
6754 static int __init ftrace_nodyn_init(void)
6759 core_initcall(ftrace_nodyn_init);
6761 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
6762 static inline void ftrace_startup_enable(int command) { }
6763 static inline void ftrace_startup_all(int command) { }
6765 # define ftrace_startup_sysctl() do { } while (0)
6766 # define ftrace_shutdown_sysctl() do { } while (0)
6768 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6772 #endif /* CONFIG_DYNAMIC_FTRACE */
6774 __init void ftrace_init_global_array_ops(struct trace_array *tr)
6776 tr->ops = &global_ops;
6777 tr->ops->private = tr;
6778 ftrace_init_trace_array(tr);
6781 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
6783 /* If we filter on pids, update to use the pid function */
6784 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
6785 if (WARN_ON(tr->ops->func != ftrace_stub))
6786 printk("ftrace ops had %pS for function\n",
6789 tr->ops->func = func;
6790 tr->ops->private = tr;
6793 void ftrace_reset_array_ops(struct trace_array *tr)
6795 tr->ops->func = ftrace_stub;
6798 static nokprobe_inline void
6799 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6800 struct ftrace_ops *ignored, struct pt_regs *regs)
6802 struct ftrace_ops *op;
6805 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
6810 * Some of the ops may be dynamically allocated,
6811 * they must be freed after a synchronize_rcu().
6813 preempt_disable_notrace();
6815 do_for_each_ftrace_op(op, ftrace_ops_list) {
6816 /* Stub functions don't need to be called nor tested */
6817 if (op->flags & FTRACE_OPS_FL_STUB)
6820 * Check the following for each ops before calling their func:
6821 * if RCU flag is set, then rcu_is_watching() must be true
6822 * if PER_CPU is set, then ftrace_function_local_disable()
6824 * Otherwise test if the ip matches the ops filter
6826 * If any of the above fails then the op->func() is not executed.
6828 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
6829 ftrace_ops_test(op, ip, regs)) {
6830 if (FTRACE_WARN_ON(!op->func)) {
6831 pr_warn("op=%p %pS\n", op, op);
6834 op->func(ip, parent_ip, op, regs);
6836 } while_for_each_ftrace_op(op);
6838 preempt_enable_notrace();
6839 trace_clear_recursion(bit);
6843 * Some archs only support passing ip and parent_ip. Even though
6844 * the list function ignores the op parameter, we do not want any
6845 * C side effects, where a function is called without the caller
6846 * sending a third parameter.
6847 * Archs are to support both the regs and ftrace_ops at the same time.
6848 * If they support ftrace_ops, it is assumed they support regs.
6849 * If call backs want to use regs, they must either check for regs
6850 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
6851 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
6852 * An architecture can pass partial regs with ftrace_ops and still
6853 * set the ARCH_SUPPORTS_FTRACE_OPS.
6855 #if ARCH_SUPPORTS_FTRACE_OPS
6856 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6857 struct ftrace_ops *op, struct pt_regs *regs)
6859 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
6861 NOKPROBE_SYMBOL(ftrace_ops_list_func);
6863 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
6865 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
6867 NOKPROBE_SYMBOL(ftrace_ops_no_ops);
6871 * If there's only one function registered but it does not support
6872 * recursion, needs RCU protection and/or requires per cpu handling, then
6873 * this function will be called by the mcount trampoline.
6875 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
6876 struct ftrace_ops *op, struct pt_regs *regs)
6880 if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching())
6883 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
6887 preempt_disable_notrace();
6889 op->func(ip, parent_ip, op, regs);
6891 preempt_enable_notrace();
6892 trace_clear_recursion(bit);
6894 NOKPROBE_SYMBOL(ftrace_ops_assist_func);
6897 * ftrace_ops_get_func - get the function a trampoline should call
6898 * @ops: the ops to get the function for
6900 * Normally the mcount trampoline will call the ops->func, but there
6901 * are times that it should not. For example, if the ops does not
6902 * have its own recursion protection, then it should call the
6903 * ftrace_ops_assist_func() instead.
6905 * Returns the function that the trampoline should call for @ops.
6907 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
6910 * If the function does not handle recursion, needs to be RCU safe,
6911 * or does per cpu logic, then we need to call the assist handler.
6913 if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
6914 ops->flags & FTRACE_OPS_FL_RCU)
6915 return ftrace_ops_assist_func;
6921 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
6922 struct task_struct *prev, struct task_struct *next)
6924 struct trace_array *tr = data;
6925 struct trace_pid_list *pid_list;
6927 pid_list = rcu_dereference_sched(tr->function_pids);
6929 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
6930 trace_ignore_this_task(pid_list, next));
6934 ftrace_pid_follow_sched_process_fork(void *data,
6935 struct task_struct *self,
6936 struct task_struct *task)
6938 struct trace_pid_list *pid_list;
6939 struct trace_array *tr = data;
6941 pid_list = rcu_dereference_sched(tr->function_pids);
6942 trace_filter_add_remove_task(pid_list, self, task);
6946 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
6948 struct trace_pid_list *pid_list;
6949 struct trace_array *tr = data;
6951 pid_list = rcu_dereference_sched(tr->function_pids);
6952 trace_filter_add_remove_task(pid_list, NULL, task);
6955 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
6958 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6960 register_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit,
6963 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6965 unregister_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit,
6970 static void clear_ftrace_pids(struct trace_array *tr)
6972 struct trace_pid_list *pid_list;
6975 pid_list = rcu_dereference_protected(tr->function_pids,
6976 lockdep_is_held(&ftrace_lock));
6980 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
6982 for_each_possible_cpu(cpu)
6983 per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = false;
6985 rcu_assign_pointer(tr->function_pids, NULL);
6987 /* Wait till all users are no longer using pid filtering */
6990 trace_free_pid_list(pid_list);
6993 void ftrace_clear_pids(struct trace_array *tr)
6995 mutex_lock(&ftrace_lock);
6997 clear_ftrace_pids(tr);
6999 mutex_unlock(&ftrace_lock);
7002 static void ftrace_pid_reset(struct trace_array *tr)
7004 mutex_lock(&ftrace_lock);
7005 clear_ftrace_pids(tr);
7007 ftrace_update_pid_func();
7008 ftrace_startup_all(0);
7010 mutex_unlock(&ftrace_lock);
7013 /* Greater than any max PID */
7014 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
7016 static void *fpid_start(struct seq_file *m, loff_t *pos)
7019 struct trace_pid_list *pid_list;
7020 struct trace_array *tr = m->private;
7022 mutex_lock(&ftrace_lock);
7023 rcu_read_lock_sched();
7025 pid_list = rcu_dereference_sched(tr->function_pids);
7028 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7030 return trace_pid_start(pid_list, pos);
7033 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
7035 struct trace_array *tr = m->private;
7036 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
7038 if (v == FTRACE_NO_PIDS) {
7042 return trace_pid_next(pid_list, v, pos);
7045 static void fpid_stop(struct seq_file *m, void *p)
7048 rcu_read_unlock_sched();
7049 mutex_unlock(&ftrace_lock);
7052 static int fpid_show(struct seq_file *m, void *v)
7054 if (v == FTRACE_NO_PIDS) {
7055 seq_puts(m, "no pid\n");
7059 return trace_pid_show(m, v);
7062 static const struct seq_operations ftrace_pid_sops = {
7063 .start = fpid_start,
7070 ftrace_pid_open(struct inode *inode, struct file *file)
7072 struct trace_array *tr = inode->i_private;
7076 ret = tracing_check_open_get_tr(tr);
7080 if ((file->f_mode & FMODE_WRITE) &&
7081 (file->f_flags & O_TRUNC))
7082 ftrace_pid_reset(tr);
7084 ret = seq_open(file, &ftrace_pid_sops);
7086 trace_array_put(tr);
7088 m = file->private_data;
7089 /* copy tr over to seq ops */
7096 static void ignore_task_cpu(void *data)
7098 struct trace_array *tr = data;
7099 struct trace_pid_list *pid_list;
7102 * This function is called by on_each_cpu() while the
7103 * event_mutex is held.
7105 pid_list = rcu_dereference_protected(tr->function_pids,
7106 mutex_is_locked(&ftrace_lock));
7108 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7109 trace_ignore_this_task(pid_list, current));
7113 ftrace_pid_write(struct file *filp, const char __user *ubuf,
7114 size_t cnt, loff_t *ppos)
7116 struct seq_file *m = filp->private_data;
7117 struct trace_array *tr = m->private;
7118 struct trace_pid_list *filtered_pids = NULL;
7119 struct trace_pid_list *pid_list;
7125 mutex_lock(&ftrace_lock);
7127 filtered_pids = rcu_dereference_protected(tr->function_pids,
7128 lockdep_is_held(&ftrace_lock));
7130 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
7134 rcu_assign_pointer(tr->function_pids, pid_list);
7136 if (filtered_pids) {
7138 trace_free_pid_list(filtered_pids);
7139 } else if (pid_list) {
7140 /* Register a probe to set whether to ignore the tracing of a task */
7141 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7145 * Ignoring of pids is done at task switch. But we have to
7146 * check for those tasks that are currently running.
7147 * Always do this in case a pid was appended or removed.
7149 on_each_cpu(ignore_task_cpu, tr, 1);
7151 ftrace_update_pid_func();
7152 ftrace_startup_all(0);
7154 mutex_unlock(&ftrace_lock);
7163 ftrace_pid_release(struct inode *inode, struct file *file)
7165 struct trace_array *tr = inode->i_private;
7167 trace_array_put(tr);
7169 return seq_release(inode, file);
7172 static const struct file_operations ftrace_pid_fops = {
7173 .open = ftrace_pid_open,
7174 .write = ftrace_pid_write,
7176 .llseek = tracing_lseek,
7177 .release = ftrace_pid_release,
7180 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
7182 trace_create_file("set_ftrace_pid", 0644, d_tracer,
7183 tr, &ftrace_pid_fops);
7186 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
7187 struct dentry *d_tracer)
7189 /* Only the top level directory has the dyn_tracefs and profile */
7190 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
7192 ftrace_init_dyn_tracefs(d_tracer);
7193 ftrace_profile_tracefs(d_tracer);
7197 * ftrace_kill - kill ftrace
7199 * This function should be used by panic code. It stops ftrace
7200 * but in a not so nice way. If you need to simply kill ftrace
7201 * from a non-atomic section, use ftrace_kill.
7203 void ftrace_kill(void)
7205 ftrace_disabled = 1;
7207 ftrace_trace_function = ftrace_stub;
7211 * Test if ftrace is dead or not.
7213 int ftrace_is_dead(void)
7215 return ftrace_disabled;
7219 * register_ftrace_function - register a function for profiling
7220 * @ops - ops structure that holds the function for profiling.
7222 * Register a function to be called by all functions in the
7225 * Note: @ops->func and all the functions it calls must be labeled
7226 * with "notrace", otherwise it will go into a
7229 int register_ftrace_function(struct ftrace_ops *ops)
7233 ftrace_ops_init(ops);
7235 mutex_lock(&ftrace_lock);
7237 ret = ftrace_startup(ops, 0);
7239 mutex_unlock(&ftrace_lock);
7243 EXPORT_SYMBOL_GPL(register_ftrace_function);
7246 * unregister_ftrace_function - unregister a function for profiling.
7247 * @ops - ops structure that holds the function to unregister
7249 * Unregister a function that was added to be called by ftrace profiling.
7251 int unregister_ftrace_function(struct ftrace_ops *ops)
7255 mutex_lock(&ftrace_lock);
7256 ret = ftrace_shutdown(ops, 0);
7257 mutex_unlock(&ftrace_lock);
7261 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
7263 static bool is_permanent_ops_registered(void)
7265 struct ftrace_ops *op;
7267 do_for_each_ftrace_op(op, ftrace_ops_list) {
7268 if (op->flags & FTRACE_OPS_FL_PERMANENT)
7270 } while_for_each_ftrace_op(op);
7276 ftrace_enable_sysctl(struct ctl_table *table, int write,
7277 void __user *buffer, size_t *lenp,
7282 mutex_lock(&ftrace_lock);
7284 if (unlikely(ftrace_disabled))
7287 ret = proc_dointvec(table, write, buffer, lenp, ppos);
7289 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
7292 if (ftrace_enabled) {
7294 /* we are starting ftrace again */
7295 if (rcu_dereference_protected(ftrace_ops_list,
7296 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
7297 update_ftrace_function();
7299 ftrace_startup_sysctl();
7302 if (is_permanent_ops_registered()) {
7303 ftrace_enabled = true;
7308 /* stopping ftrace calls (just send to ftrace_stub) */
7309 ftrace_trace_function = ftrace_stub;
7311 ftrace_shutdown_sysctl();
7314 last_ftrace_enabled = !!ftrace_enabled;
7316 mutex_unlock(&ftrace_lock);