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_BITS 7
66 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
67 #define FTRACE_HASH_DEFAULT_BITS 10
68 #define FTRACE_HASH_MAX_BITS 12
70 #ifdef CONFIG_DYNAMIC_FTRACE
71 #define INIT_OPS_HASH(opsname) \
72 .func_hash = &opsname.local_hash, \
73 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
75 #define INIT_OPS_HASH(opsname)
79 FTRACE_MODIFY_ENABLE_FL = (1 << 0),
80 FTRACE_MODIFY_MAY_SLEEP_FL = (1 << 1),
83 struct ftrace_ops ftrace_list_end __read_mostly = {
85 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
86 INIT_OPS_HASH(ftrace_list_end)
89 /* ftrace_enabled is a method to turn ftrace on or off */
90 int ftrace_enabled __read_mostly;
91 static int last_ftrace_enabled;
93 /* Current function tracing op */
94 struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
95 /* What to set function_trace_op to */
96 static struct ftrace_ops *set_function_trace_op;
98 static bool ftrace_pids_enabled(struct ftrace_ops *ops)
100 struct trace_array *tr;
102 if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
107 return tr->function_pids != NULL;
110 static void ftrace_update_trampoline(struct ftrace_ops *ops);
113 * ftrace_disabled is set when an anomaly is discovered.
114 * ftrace_disabled is much stronger than ftrace_enabled.
116 static int ftrace_disabled __read_mostly;
118 DEFINE_MUTEX(ftrace_lock);
120 struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
121 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
122 struct ftrace_ops global_ops;
124 #if ARCH_SUPPORTS_FTRACE_OPS
125 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
126 struct ftrace_ops *op, struct pt_regs *regs);
128 /* See comment below, where ftrace_ops_list_func is defined */
129 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
130 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
133 static inline void ftrace_ops_init(struct ftrace_ops *ops)
135 #ifdef CONFIG_DYNAMIC_FTRACE
136 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
137 mutex_init(&ops->local_hash.regex_lock);
138 ops->func_hash = &ops->local_hash;
139 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
144 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
145 struct ftrace_ops *op, struct pt_regs *regs)
147 struct trace_array *tr = op->private;
149 if (tr && this_cpu_read(tr->trace_buffer.data->ftrace_ignore_pid))
152 op->saved_func(ip, parent_ip, op, regs);
155 static void ftrace_sync(struct work_struct *work)
158 * This function is just a stub to implement a hard force
159 * of synchronize_rcu(). This requires synchronizing
160 * tasks even in userspace and idle.
162 * Yes, function tracing is rude.
166 static void ftrace_sync_ipi(void *data)
168 /* Probably not needed, but do it anyway */
172 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
175 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
176 * then it needs to call the list anyway.
178 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
179 FTRACE_FORCE_LIST_FUNC)
180 return ftrace_ops_list_func;
182 return ftrace_ops_get_func(ops);
185 static void update_ftrace_function(void)
190 * Prepare the ftrace_ops that the arch callback will use.
191 * If there's only one ftrace_ops registered, the ftrace_ops_list
192 * will point to the ops we want.
194 set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
195 lockdep_is_held(&ftrace_lock));
197 /* If there's no ftrace_ops registered, just call the stub function */
198 if (set_function_trace_op == &ftrace_list_end) {
202 * If we are at the end of the list and this ops is
203 * recursion safe and not dynamic and the arch supports passing ops,
204 * then have the mcount trampoline call the function directly.
206 } else if (rcu_dereference_protected(ftrace_ops_list->next,
207 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
208 func = ftrace_ops_get_list_func(ftrace_ops_list);
211 /* Just use the default ftrace_ops */
212 set_function_trace_op = &ftrace_list_end;
213 func = ftrace_ops_list_func;
216 update_function_graph_func();
218 /* If there's no change, then do nothing more here */
219 if (ftrace_trace_function == func)
223 * If we are using the list function, it doesn't care
224 * about the function_trace_ops.
226 if (func == ftrace_ops_list_func) {
227 ftrace_trace_function = func;
229 * Don't even bother setting function_trace_ops,
230 * it would be racy to do so anyway.
235 #ifndef CONFIG_DYNAMIC_FTRACE
237 * For static tracing, we need to be a bit more careful.
238 * The function change takes affect immediately. Thus,
239 * we need to coorditate the setting of the function_trace_ops
240 * with the setting of the ftrace_trace_function.
242 * Set the function to the list ops, which will call the
243 * function we want, albeit indirectly, but it handles the
244 * ftrace_ops and doesn't depend on function_trace_op.
246 ftrace_trace_function = ftrace_ops_list_func;
248 * Make sure all CPUs see this. Yes this is slow, but static
249 * tracing is slow and nasty to have enabled.
251 schedule_on_each_cpu(ftrace_sync);
252 /* Now all cpus are using the list ops. */
253 function_trace_op = set_function_trace_op;
254 /* Make sure the function_trace_op is visible on all CPUs */
256 /* Nasty way to force a rmb on all cpus */
257 smp_call_function(ftrace_sync_ipi, NULL, 1);
258 /* OK, we are all set to update the ftrace_trace_function now! */
259 #endif /* !CONFIG_DYNAMIC_FTRACE */
261 ftrace_trace_function = func;
264 static void add_ftrace_ops(struct ftrace_ops __rcu **list,
265 struct ftrace_ops *ops)
267 rcu_assign_pointer(ops->next, *list);
270 * We are entering ops into the list but another
271 * CPU might be walking that list. We need to make sure
272 * the ops->next pointer is valid before another CPU sees
273 * the ops pointer included into the list.
275 rcu_assign_pointer(*list, ops);
278 static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
279 struct ftrace_ops *ops)
281 struct ftrace_ops **p;
284 * If we are removing the last function, then simply point
285 * to the ftrace_stub.
287 if (rcu_dereference_protected(*list,
288 lockdep_is_held(&ftrace_lock)) == ops &&
289 rcu_dereference_protected(ops->next,
290 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
291 *list = &ftrace_list_end;
295 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
306 static void ftrace_update_trampoline(struct ftrace_ops *ops);
308 int __register_ftrace_function(struct ftrace_ops *ops)
310 if (ops->flags & FTRACE_OPS_FL_DELETED)
313 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
316 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
318 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
319 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
320 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
322 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
323 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
326 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
327 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
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(void *p1, void *p2)
468 struct ftrace_profile *a = p1;
469 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(void *p1, void *p2)
482 struct ftrace_profile *a = p1;
483 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_entry {
1022 struct hlist_node hlist;
1026 struct ftrace_func_probe {
1027 struct ftrace_probe_ops *probe_ops;
1028 struct ftrace_ops ops;
1029 struct trace_array *tr;
1030 struct list_head list;
1036 * We make these constant because no one should touch them,
1037 * but they are used as the default "empty hash", to avoid allocating
1038 * it all the time. These are in a read only section such that if
1039 * anyone does try to modify it, it will cause an exception.
1041 static const struct hlist_head empty_buckets[1];
1042 static const struct ftrace_hash empty_hash = {
1043 .buckets = (struct hlist_head *)empty_buckets,
1045 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1047 struct ftrace_ops global_ops = {
1048 .func = ftrace_stub,
1049 .local_hash.notrace_hash = EMPTY_HASH,
1050 .local_hash.filter_hash = EMPTY_HASH,
1051 INIT_OPS_HASH(global_ops)
1052 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
1053 FTRACE_OPS_FL_INITIALIZED |
1058 * Used by the stack undwinder to know about dynamic ftrace trampolines.
1060 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
1062 struct ftrace_ops *op = NULL;
1065 * Some of the ops may be dynamically allocated,
1066 * they are freed after a synchronize_rcu().
1068 preempt_disable_notrace();
1070 do_for_each_ftrace_op(op, ftrace_ops_list) {
1072 * This is to check for dynamically allocated trampolines.
1073 * Trampolines that are in kernel text will have
1074 * core_kernel_text() return true.
1076 if (op->trampoline && op->trampoline_size)
1077 if (addr >= op->trampoline &&
1078 addr < op->trampoline + op->trampoline_size) {
1079 preempt_enable_notrace();
1082 } while_for_each_ftrace_op(op);
1083 preempt_enable_notrace();
1089 * This is used by __kernel_text_address() to return true if the
1090 * address is on a dynamically allocated trampoline that would
1091 * not return true for either core_kernel_text() or
1092 * is_module_text_address().
1094 bool is_ftrace_trampoline(unsigned long addr)
1096 return ftrace_ops_trampoline(addr) != NULL;
1099 struct ftrace_page {
1100 struct ftrace_page *next;
1101 struct dyn_ftrace *records;
1106 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1107 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1109 /* estimate from running different kernels */
1110 #define NR_TO_INIT 10000
1112 static struct ftrace_page *ftrace_pages_start;
1113 static struct ftrace_page *ftrace_pages;
1115 static __always_inline unsigned long
1116 ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1118 if (hash->size_bits > 0)
1119 return hash_long(ip, hash->size_bits);
1124 /* Only use this function if ftrace_hash_empty() has already been tested */
1125 static __always_inline struct ftrace_func_entry *
1126 __ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1129 struct ftrace_func_entry *entry;
1130 struct hlist_head *hhd;
1132 key = ftrace_hash_key(hash, ip);
1133 hhd = &hash->buckets[key];
1135 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1136 if (entry->ip == ip)
1143 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1144 * @hash: The hash to look at
1145 * @ip: The instruction pointer to test
1147 * Search a given @hash to see if a given instruction pointer (@ip)
1150 * Returns the entry that holds the @ip if found. NULL otherwise.
1152 struct ftrace_func_entry *
1153 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1155 if (ftrace_hash_empty(hash))
1158 return __ftrace_lookup_ip(hash, ip);
1161 static void __add_hash_entry(struct ftrace_hash *hash,
1162 struct ftrace_func_entry *entry)
1164 struct hlist_head *hhd;
1167 key = ftrace_hash_key(hash, entry->ip);
1168 hhd = &hash->buckets[key];
1169 hlist_add_head(&entry->hlist, hhd);
1173 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1175 struct ftrace_func_entry *entry;
1177 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1182 __add_hash_entry(hash, entry);
1188 free_hash_entry(struct ftrace_hash *hash,
1189 struct ftrace_func_entry *entry)
1191 hlist_del(&entry->hlist);
1197 remove_hash_entry(struct ftrace_hash *hash,
1198 struct ftrace_func_entry *entry)
1200 hlist_del_rcu(&entry->hlist);
1204 static void ftrace_hash_clear(struct ftrace_hash *hash)
1206 struct hlist_head *hhd;
1207 struct hlist_node *tn;
1208 struct ftrace_func_entry *entry;
1209 int size = 1 << hash->size_bits;
1215 for (i = 0; i < size; i++) {
1216 hhd = &hash->buckets[i];
1217 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1218 free_hash_entry(hash, entry);
1220 FTRACE_WARN_ON(hash->count);
1223 static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1225 list_del(&ftrace_mod->list);
1226 kfree(ftrace_mod->module);
1227 kfree(ftrace_mod->func);
1231 static void clear_ftrace_mod_list(struct list_head *head)
1233 struct ftrace_mod_load *p, *n;
1235 /* stack tracer isn't supported yet */
1239 mutex_lock(&ftrace_lock);
1240 list_for_each_entry_safe(p, n, head, list)
1242 mutex_unlock(&ftrace_lock);
1245 static void free_ftrace_hash(struct ftrace_hash *hash)
1247 if (!hash || hash == EMPTY_HASH)
1249 ftrace_hash_clear(hash);
1250 kfree(hash->buckets);
1254 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1256 struct ftrace_hash *hash;
1258 hash = container_of(rcu, struct ftrace_hash, rcu);
1259 free_ftrace_hash(hash);
1262 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1264 if (!hash || hash == EMPTY_HASH)
1266 call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
1269 void ftrace_free_filter(struct ftrace_ops *ops)
1271 ftrace_ops_init(ops);
1272 free_ftrace_hash(ops->func_hash->filter_hash);
1273 free_ftrace_hash(ops->func_hash->notrace_hash);
1276 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1278 struct ftrace_hash *hash;
1281 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1285 size = 1 << size_bits;
1286 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1288 if (!hash->buckets) {
1293 hash->size_bits = size_bits;
1299 static int ftrace_add_mod(struct trace_array *tr,
1300 const char *func, const char *module,
1303 struct ftrace_mod_load *ftrace_mod;
1304 struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1306 ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1310 INIT_LIST_HEAD(&ftrace_mod->list);
1311 ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1312 ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1313 ftrace_mod->enable = enable;
1315 if (!ftrace_mod->func || !ftrace_mod->module)
1318 list_add(&ftrace_mod->list, mod_head);
1323 free_ftrace_mod(ftrace_mod);
1328 static struct ftrace_hash *
1329 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1331 struct ftrace_func_entry *entry;
1332 struct ftrace_hash *new_hash;
1337 new_hash = alloc_ftrace_hash(size_bits);
1342 new_hash->flags = hash->flags;
1345 if (ftrace_hash_empty(hash))
1348 size = 1 << hash->size_bits;
1349 for (i = 0; i < size; i++) {
1350 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1351 ret = add_hash_entry(new_hash, entry->ip);
1357 FTRACE_WARN_ON(new_hash->count != hash->count);
1362 free_ftrace_hash(new_hash);
1367 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1369 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1371 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1372 struct ftrace_hash *new_hash);
1374 static struct ftrace_hash *
1375 __ftrace_hash_move(struct ftrace_hash *src)
1377 struct ftrace_func_entry *entry;
1378 struct hlist_node *tn;
1379 struct hlist_head *hhd;
1380 struct ftrace_hash *new_hash;
1381 int size = src->count;
1386 * If the new source is empty, just return the empty_hash.
1388 if (ftrace_hash_empty(src))
1392 * Make the hash size about 1/2 the # found
1394 for (size /= 2; size; size >>= 1)
1397 /* Don't allocate too much */
1398 if (bits > FTRACE_HASH_MAX_BITS)
1399 bits = FTRACE_HASH_MAX_BITS;
1401 new_hash = alloc_ftrace_hash(bits);
1405 new_hash->flags = src->flags;
1407 size = 1 << src->size_bits;
1408 for (i = 0; i < size; i++) {
1409 hhd = &src->buckets[i];
1410 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1411 remove_hash_entry(src, entry);
1412 __add_hash_entry(new_hash, entry);
1420 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1421 struct ftrace_hash **dst, struct ftrace_hash *src)
1423 struct ftrace_hash *new_hash;
1426 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1427 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1430 new_hash = __ftrace_hash_move(src);
1434 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1436 /* IPMODIFY should be updated only when filter_hash updating */
1437 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1439 free_ftrace_hash(new_hash);
1445 * Remove the current set, update the hash and add
1448 ftrace_hash_rec_disable_modify(ops, enable);
1450 rcu_assign_pointer(*dst, new_hash);
1452 ftrace_hash_rec_enable_modify(ops, enable);
1457 static bool hash_contains_ip(unsigned long ip,
1458 struct ftrace_ops_hash *hash)
1461 * The function record is a match if it exists in the filter
1462 * hash and not in the notrace hash. Note, an emty hash is
1463 * considered a match for the filter hash, but an empty
1464 * notrace hash is considered not in the notrace hash.
1466 return (ftrace_hash_empty(hash->filter_hash) ||
1467 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1468 (ftrace_hash_empty(hash->notrace_hash) ||
1469 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1473 * Test the hashes for this ops to see if we want to call
1474 * the ops->func or not.
1476 * It's a match if the ip is in the ops->filter_hash or
1477 * the filter_hash does not exist or is empty,
1479 * the ip is not in the ops->notrace_hash.
1481 * This needs to be called with preemption disabled as
1482 * the hashes are freed with call_rcu().
1485 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1487 struct ftrace_ops_hash hash;
1490 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1492 * There's a small race when adding ops that the ftrace handler
1493 * that wants regs, may be called without them. We can not
1494 * allow that handler to be called if regs is NULL.
1496 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1500 rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1501 rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1503 if (hash_contains_ip(ip, &hash))
1512 * This is a double for. Do not use 'break' to break out of the loop,
1513 * you must use a goto.
1515 #define do_for_each_ftrace_rec(pg, rec) \
1516 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1518 for (_____i = 0; _____i < pg->index; _____i++) { \
1519 rec = &pg->records[_____i];
1521 #define while_for_each_ftrace_rec() \
1526 static int ftrace_cmp_recs(const void *a, const void *b)
1528 const struct dyn_ftrace *key = a;
1529 const struct dyn_ftrace *rec = b;
1531 if (key->flags < rec->ip)
1533 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1539 * ftrace_location_range - return the first address of a traced location
1540 * if it touches the given ip range
1541 * @start: start of range to search.
1542 * @end: end of range to search (inclusive). @end points to the last byte
1545 * Returns rec->ip if the related ftrace location is a least partly within
1546 * the given address range. That is, the first address of the instruction
1547 * that is either a NOP or call to the function tracer. It checks the ftrace
1548 * internal tables to determine if the address belongs or not.
1550 unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1552 struct ftrace_page *pg;
1553 struct dyn_ftrace *rec;
1554 struct dyn_ftrace key;
1557 key.flags = end; /* overload flags, as it is unsigned long */
1559 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1560 if (pg->index == 0 ||
1561 end < pg->records[0].ip ||
1562 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1564 rec = bsearch(&key, pg->records, pg->index,
1565 sizeof(struct dyn_ftrace),
1575 * ftrace_location - return true if the ip giving is a traced location
1576 * @ip: the instruction pointer to check
1578 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1579 * That is, the instruction that is either a NOP or call to
1580 * the function tracer. It checks the ftrace internal tables to
1581 * determine if the address belongs or not.
1583 unsigned long ftrace_location(unsigned long ip)
1585 return ftrace_location_range(ip, ip);
1589 * ftrace_text_reserved - return true if range contains an ftrace location
1590 * @start: start of range to search
1591 * @end: end of range to search (inclusive). @end points to the last byte to check.
1593 * Returns 1 if @start and @end contains a ftrace location.
1594 * That is, the instruction that is either a NOP or call to
1595 * the function tracer. It checks the ftrace internal tables to
1596 * determine if the address belongs or not.
1598 int ftrace_text_reserved(const void *start, const void *end)
1602 ret = ftrace_location_range((unsigned long)start,
1603 (unsigned long)end);
1608 /* Test if ops registered to this rec needs regs */
1609 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1611 struct ftrace_ops *ops;
1612 bool keep_regs = false;
1614 for (ops = ftrace_ops_list;
1615 ops != &ftrace_list_end; ops = ops->next) {
1616 /* pass rec in as regs to have non-NULL val */
1617 if (ftrace_ops_test(ops, rec->ip, rec)) {
1618 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1628 static struct ftrace_ops *
1629 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1630 static struct ftrace_ops *
1631 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude);
1632 static struct ftrace_ops *
1633 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1635 static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1639 struct ftrace_hash *hash;
1640 struct ftrace_hash *other_hash;
1641 struct ftrace_page *pg;
1642 struct dyn_ftrace *rec;
1643 bool update = false;
1647 /* Only update if the ops has been registered */
1648 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1652 * In the filter_hash case:
1653 * If the count is zero, we update all records.
1654 * Otherwise we just update the items in the hash.
1656 * In the notrace_hash case:
1657 * We enable the update in the hash.
1658 * As disabling notrace means enabling the tracing,
1659 * and enabling notrace means disabling, the inc variable
1663 hash = ops->func_hash->filter_hash;
1664 other_hash = ops->func_hash->notrace_hash;
1665 if (ftrace_hash_empty(hash))
1669 hash = ops->func_hash->notrace_hash;
1670 other_hash = ops->func_hash->filter_hash;
1672 * If the notrace hash has no items,
1673 * then there's nothing to do.
1675 if (ftrace_hash_empty(hash))
1679 do_for_each_ftrace_rec(pg, rec) {
1680 int in_other_hash = 0;
1684 if (rec->flags & FTRACE_FL_DISABLED)
1689 * Only the filter_hash affects all records.
1690 * Update if the record is not in the notrace hash.
1692 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1695 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1696 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1699 * If filter_hash is set, we want to match all functions
1700 * that are in the hash but not in the other hash.
1702 * If filter_hash is not set, then we are decrementing.
1703 * That means we match anything that is in the hash
1704 * and also in the other_hash. That is, we need to turn
1705 * off functions in the other hash because they are disabled
1708 if (filter_hash && in_hash && !in_other_hash)
1710 else if (!filter_hash && in_hash &&
1711 (in_other_hash || ftrace_hash_empty(other_hash)))
1719 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1723 * If there's only a single callback registered to a
1724 * function, and the ops has a trampoline registered
1725 * for it, then we can call it directly.
1727 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1728 rec->flags |= FTRACE_FL_TRAMP;
1731 * If we are adding another function callback
1732 * to this function, and the previous had a
1733 * custom trampoline in use, then we need to go
1734 * back to the default trampoline.
1736 rec->flags &= ~FTRACE_FL_TRAMP;
1739 * If any ops wants regs saved for this function
1740 * then all ops will get saved regs.
1742 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1743 rec->flags |= FTRACE_FL_REGS;
1745 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1750 * If the rec had REGS enabled and the ops that is
1751 * being removed had REGS set, then see if there is
1752 * still any ops for this record that wants regs.
1753 * If not, we can stop recording them.
1755 if (ftrace_rec_count(rec) > 0 &&
1756 rec->flags & FTRACE_FL_REGS &&
1757 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1758 if (!test_rec_ops_needs_regs(rec))
1759 rec->flags &= ~FTRACE_FL_REGS;
1763 * The TRAMP needs to be set only if rec count
1764 * is decremented to one, and the ops that is
1765 * left has a trampoline. As TRAMP can only be
1766 * enabled if there is only a single ops attached
1769 if (ftrace_rec_count(rec) == 1 &&
1770 ftrace_find_tramp_ops_any_other(rec, ops))
1771 rec->flags |= FTRACE_FL_TRAMP;
1773 rec->flags &= ~FTRACE_FL_TRAMP;
1776 * flags will be cleared in ftrace_check_record()
1777 * if rec count is zero.
1782 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1783 update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1785 /* Shortcut, if we handled all records, we are done. */
1786 if (!all && count == hash->count)
1788 } while_for_each_ftrace_rec();
1793 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1796 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1799 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1802 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1805 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1806 int filter_hash, int inc)
1808 struct ftrace_ops *op;
1810 __ftrace_hash_rec_update(ops, filter_hash, inc);
1812 if (ops->func_hash != &global_ops.local_hash)
1816 * If the ops shares the global_ops hash, then we need to update
1817 * all ops that are enabled and use this hash.
1819 do_for_each_ftrace_op(op, ftrace_ops_list) {
1823 if (op->func_hash == &global_ops.local_hash)
1824 __ftrace_hash_rec_update(op, filter_hash, inc);
1825 } while_for_each_ftrace_op(op);
1828 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1831 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1834 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1837 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1841 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1842 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1843 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1844 * Note that old_hash and new_hash has below meanings
1845 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1846 * - If the hash is EMPTY_HASH, it hits nothing
1847 * - Anything else hits the recs which match the hash entries.
1849 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1850 struct ftrace_hash *old_hash,
1851 struct ftrace_hash *new_hash)
1853 struct ftrace_page *pg;
1854 struct dyn_ftrace *rec, *end = NULL;
1857 /* Only update if the ops has been registered */
1858 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1861 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1865 * Since the IPMODIFY is a very address sensitive action, we do not
1866 * allow ftrace_ops to set all functions to new hash.
1868 if (!new_hash || !old_hash)
1871 /* Update rec->flags */
1872 do_for_each_ftrace_rec(pg, rec) {
1874 if (rec->flags & FTRACE_FL_DISABLED)
1877 /* We need to update only differences of filter_hash */
1878 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1879 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1880 if (in_old == in_new)
1884 /* New entries must ensure no others are using it */
1885 if (rec->flags & FTRACE_FL_IPMODIFY)
1887 rec->flags |= FTRACE_FL_IPMODIFY;
1888 } else /* Removed entry */
1889 rec->flags &= ~FTRACE_FL_IPMODIFY;
1890 } while_for_each_ftrace_rec();
1897 /* Roll back what we did above */
1898 do_for_each_ftrace_rec(pg, rec) {
1900 if (rec->flags & FTRACE_FL_DISABLED)
1906 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1907 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1908 if (in_old == in_new)
1912 rec->flags &= ~FTRACE_FL_IPMODIFY;
1914 rec->flags |= FTRACE_FL_IPMODIFY;
1915 } while_for_each_ftrace_rec();
1921 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1923 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1925 if (ftrace_hash_empty(hash))
1928 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1931 /* Disabling always succeeds */
1932 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1934 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1936 if (ftrace_hash_empty(hash))
1939 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1942 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1943 struct ftrace_hash *new_hash)
1945 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1947 if (ftrace_hash_empty(old_hash))
1950 if (ftrace_hash_empty(new_hash))
1953 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
1956 static void print_ip_ins(const char *fmt, const unsigned char *p)
1958 char ins[MCOUNT_INSN_SIZE];
1961 if (probe_kernel_read(ins, p, MCOUNT_INSN_SIZE)) {
1962 printk(KERN_CONT "%s[FAULT] %px\n", fmt, p);
1966 printk(KERN_CONT "%s", fmt);
1968 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1969 printk(KERN_CONT "%s%02x", i ? ":" : "", ins[i]);
1972 enum ftrace_bug_type ftrace_bug_type;
1973 const void *ftrace_expected;
1975 static void print_bug_type(void)
1977 switch (ftrace_bug_type) {
1978 case FTRACE_BUG_UNKNOWN:
1980 case FTRACE_BUG_INIT:
1981 pr_info("Initializing ftrace call sites\n");
1983 case FTRACE_BUG_NOP:
1984 pr_info("Setting ftrace call site to NOP\n");
1986 case FTRACE_BUG_CALL:
1987 pr_info("Setting ftrace call site to call ftrace function\n");
1989 case FTRACE_BUG_UPDATE:
1990 pr_info("Updating ftrace call site to call a different ftrace function\n");
1996 * ftrace_bug - report and shutdown function tracer
1997 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1998 * @rec: The record that failed
2000 * The arch code that enables or disables the function tracing
2001 * can call ftrace_bug() when it has detected a problem in
2002 * modifying the code. @failed should be one of either:
2003 * EFAULT - if the problem happens on reading the @ip address
2004 * EINVAL - if what is read at @ip is not what was expected
2005 * EPERM - if the problem happens on writing to the @ip address
2007 void ftrace_bug(int failed, struct dyn_ftrace *rec)
2009 unsigned long ip = rec ? rec->ip : 0;
2013 FTRACE_WARN_ON_ONCE(1);
2014 pr_info("ftrace faulted on modifying ");
2018 FTRACE_WARN_ON_ONCE(1);
2019 pr_info("ftrace failed to modify ");
2021 print_ip_ins(" actual: ", (unsigned char *)ip);
2023 if (ftrace_expected) {
2024 print_ip_ins(" expected: ", ftrace_expected);
2029 FTRACE_WARN_ON_ONCE(1);
2030 pr_info("ftrace faulted on writing ");
2034 FTRACE_WARN_ON_ONCE(1);
2035 pr_info("ftrace faulted on unknown error ");
2040 struct ftrace_ops *ops = NULL;
2042 pr_info("ftrace record flags: %lx\n", rec->flags);
2043 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2044 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2045 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2046 ops = ftrace_find_tramp_ops_any(rec);
2049 pr_cont("\ttramp: %pS (%pS)",
2050 (void *)ops->trampoline,
2052 ops = ftrace_find_tramp_ops_next(rec, ops);
2055 pr_cont("\ttramp: ERROR!");
2058 ip = ftrace_get_addr_curr(rec);
2059 pr_cont("\n expected tramp: %lx\n", ip);
2063 static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2065 unsigned long flag = 0UL;
2067 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2069 if (rec->flags & FTRACE_FL_DISABLED)
2070 return FTRACE_UPDATE_IGNORE;
2073 * If we are updating calls:
2075 * If the record has a ref count, then we need to enable it
2076 * because someone is using it.
2078 * Otherwise we make sure its disabled.
2080 * If we are disabling calls, then disable all records that
2083 if (enable && ftrace_rec_count(rec))
2084 flag = FTRACE_FL_ENABLED;
2087 * If enabling and the REGS flag does not match the REGS_EN, or
2088 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2089 * this record. Set flags to fail the compare against ENABLED.
2092 if (!(rec->flags & FTRACE_FL_REGS) !=
2093 !(rec->flags & FTRACE_FL_REGS_EN))
2094 flag |= FTRACE_FL_REGS;
2096 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2097 !(rec->flags & FTRACE_FL_TRAMP_EN))
2098 flag |= FTRACE_FL_TRAMP;
2101 /* If the state of this record hasn't changed, then do nothing */
2102 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2103 return FTRACE_UPDATE_IGNORE;
2106 /* Save off if rec is being enabled (for return value) */
2107 flag ^= rec->flags & FTRACE_FL_ENABLED;
2110 rec->flags |= FTRACE_FL_ENABLED;
2111 if (flag & FTRACE_FL_REGS) {
2112 if (rec->flags & FTRACE_FL_REGS)
2113 rec->flags |= FTRACE_FL_REGS_EN;
2115 rec->flags &= ~FTRACE_FL_REGS_EN;
2117 if (flag & FTRACE_FL_TRAMP) {
2118 if (rec->flags & FTRACE_FL_TRAMP)
2119 rec->flags |= FTRACE_FL_TRAMP_EN;
2121 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2126 * If this record is being updated from a nop, then
2127 * return UPDATE_MAKE_CALL.
2129 * return UPDATE_MODIFY_CALL to tell the caller to convert
2130 * from the save regs, to a non-save regs function or
2131 * vice versa, or from a trampoline call.
2133 if (flag & FTRACE_FL_ENABLED) {
2134 ftrace_bug_type = FTRACE_BUG_CALL;
2135 return FTRACE_UPDATE_MAKE_CALL;
2138 ftrace_bug_type = FTRACE_BUG_UPDATE;
2139 return FTRACE_UPDATE_MODIFY_CALL;
2143 /* If there's no more users, clear all flags */
2144 if (!ftrace_rec_count(rec))
2148 * Just disable the record, but keep the ops TRAMP
2149 * and REGS states. The _EN flags must be disabled though.
2151 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2155 ftrace_bug_type = FTRACE_BUG_NOP;
2156 return FTRACE_UPDATE_MAKE_NOP;
2160 * ftrace_update_record, set a record that now is tracing or not
2161 * @rec: the record to update
2162 * @enable: set to true if the record is tracing, false to force disable
2164 * The records that represent all functions that can be traced need
2165 * to be updated when tracing has been enabled.
2167 int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2169 return ftrace_check_record(rec, enable, true);
2173 * ftrace_test_record, check if the record has been enabled or not
2174 * @rec: the record to test
2175 * @enable: set to true to check if enabled, false if it is disabled
2177 * The arch code may need to test if a record is already set to
2178 * tracing to determine how to modify the function code that it
2181 int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2183 return ftrace_check_record(rec, enable, false);
2186 static struct ftrace_ops *
2187 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2189 struct ftrace_ops *op;
2190 unsigned long ip = rec->ip;
2192 do_for_each_ftrace_op(op, ftrace_ops_list) {
2194 if (!op->trampoline)
2197 if (hash_contains_ip(ip, op->func_hash))
2199 } while_for_each_ftrace_op(op);
2204 static struct ftrace_ops *
2205 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude)
2207 struct ftrace_ops *op;
2208 unsigned long ip = rec->ip;
2210 do_for_each_ftrace_op(op, ftrace_ops_list) {
2212 if (op == op_exclude || !op->trampoline)
2215 if (hash_contains_ip(ip, op->func_hash))
2217 } while_for_each_ftrace_op(op);
2222 static struct ftrace_ops *
2223 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2224 struct ftrace_ops *op)
2226 unsigned long ip = rec->ip;
2228 while_for_each_ftrace_op(op) {
2230 if (!op->trampoline)
2233 if (hash_contains_ip(ip, op->func_hash))
2240 static struct ftrace_ops *
2241 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2243 struct ftrace_ops *op;
2244 unsigned long ip = rec->ip;
2247 * Need to check removed ops first.
2248 * If they are being removed, and this rec has a tramp,
2249 * and this rec is in the ops list, then it would be the
2250 * one with the tramp.
2253 if (hash_contains_ip(ip, &removed_ops->old_hash))
2258 * Need to find the current trampoline for a rec.
2259 * Now, a trampoline is only attached to a rec if there
2260 * was a single 'ops' attached to it. But this can be called
2261 * when we are adding another op to the rec or removing the
2262 * current one. Thus, if the op is being added, we can
2263 * ignore it because it hasn't attached itself to the rec
2266 * If an ops is being modified (hooking to different functions)
2267 * then we don't care about the new functions that are being
2268 * added, just the old ones (that are probably being removed).
2270 * If we are adding an ops to a function that already is using
2271 * a trampoline, it needs to be removed (trampolines are only
2272 * for single ops connected), then an ops that is not being
2273 * modified also needs to be checked.
2275 do_for_each_ftrace_op(op, ftrace_ops_list) {
2277 if (!op->trampoline)
2281 * If the ops is being added, it hasn't gotten to
2282 * the point to be removed from this tree yet.
2284 if (op->flags & FTRACE_OPS_FL_ADDING)
2289 * If the ops is being modified and is in the old
2290 * hash, then it is probably being removed from this
2293 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2294 hash_contains_ip(ip, &op->old_hash))
2297 * If the ops is not being added or modified, and it's
2298 * in its normal filter hash, then this must be the one
2301 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2302 hash_contains_ip(ip, op->func_hash))
2305 } while_for_each_ftrace_op(op);
2310 static struct ftrace_ops *
2311 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2313 struct ftrace_ops *op;
2314 unsigned long ip = rec->ip;
2316 do_for_each_ftrace_op(op, ftrace_ops_list) {
2317 /* pass rec in as regs to have non-NULL val */
2318 if (hash_contains_ip(ip, op->func_hash))
2320 } while_for_each_ftrace_op(op);
2326 * ftrace_get_addr_new - Get the call address to set to
2327 * @rec: The ftrace record descriptor
2329 * If the record has the FTRACE_FL_REGS set, that means that it
2330 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2331 * is not not set, then it wants to convert to the normal callback.
2333 * Returns the address of the trampoline to set to
2335 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2337 struct ftrace_ops *ops;
2339 /* Trampolines take precedence over regs */
2340 if (rec->flags & FTRACE_FL_TRAMP) {
2341 ops = ftrace_find_tramp_ops_new(rec);
2342 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2343 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2344 (void *)rec->ip, (void *)rec->ip, rec->flags);
2345 /* Ftrace is shutting down, return anything */
2346 return (unsigned long)FTRACE_ADDR;
2348 return ops->trampoline;
2351 if (rec->flags & FTRACE_FL_REGS)
2352 return (unsigned long)FTRACE_REGS_ADDR;
2354 return (unsigned long)FTRACE_ADDR;
2358 * ftrace_get_addr_curr - Get the call address that is already there
2359 * @rec: The ftrace record descriptor
2361 * The FTRACE_FL_REGS_EN is set when the record already points to
2362 * a function that saves all the regs. Basically the '_EN' version
2363 * represents the current state of the function.
2365 * Returns the address of the trampoline that is currently being called
2367 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2369 struct ftrace_ops *ops;
2371 /* Trampolines take precedence over regs */
2372 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2373 ops = ftrace_find_tramp_ops_curr(rec);
2374 if (FTRACE_WARN_ON(!ops)) {
2375 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2376 (void *)rec->ip, (void *)rec->ip);
2377 /* Ftrace is shutting down, return anything */
2378 return (unsigned long)FTRACE_ADDR;
2380 return ops->trampoline;
2383 if (rec->flags & FTRACE_FL_REGS_EN)
2384 return (unsigned long)FTRACE_REGS_ADDR;
2386 return (unsigned long)FTRACE_ADDR;
2390 __ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2392 unsigned long ftrace_old_addr;
2393 unsigned long ftrace_addr;
2396 ftrace_addr = ftrace_get_addr_new(rec);
2398 /* This needs to be done before we call ftrace_update_record */
2399 ftrace_old_addr = ftrace_get_addr_curr(rec);
2401 ret = ftrace_update_record(rec, enable);
2403 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2406 case FTRACE_UPDATE_IGNORE:
2409 case FTRACE_UPDATE_MAKE_CALL:
2410 ftrace_bug_type = FTRACE_BUG_CALL;
2411 return ftrace_make_call(rec, ftrace_addr);
2413 case FTRACE_UPDATE_MAKE_NOP:
2414 ftrace_bug_type = FTRACE_BUG_NOP;
2415 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2417 case FTRACE_UPDATE_MODIFY_CALL:
2418 ftrace_bug_type = FTRACE_BUG_UPDATE;
2419 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2422 return -1; /* unknown ftrace bug */
2425 void __weak ftrace_replace_code(int mod_flags)
2427 struct dyn_ftrace *rec;
2428 struct ftrace_page *pg;
2429 bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2430 int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2433 if (unlikely(ftrace_disabled))
2436 do_for_each_ftrace_rec(pg, rec) {
2438 if (rec->flags & FTRACE_FL_DISABLED)
2441 failed = __ftrace_replace_code(rec, enable);
2443 ftrace_bug(failed, rec);
2444 /* Stop processing */
2449 } while_for_each_ftrace_rec();
2452 struct ftrace_rec_iter {
2453 struct ftrace_page *pg;
2458 * ftrace_rec_iter_start, start up iterating over traced functions
2460 * Returns an iterator handle that is used to iterate over all
2461 * the records that represent address locations where functions
2464 * May return NULL if no records are available.
2466 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2469 * We only use a single iterator.
2470 * Protected by the ftrace_lock mutex.
2472 static struct ftrace_rec_iter ftrace_rec_iter;
2473 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2475 iter->pg = ftrace_pages_start;
2478 /* Could have empty pages */
2479 while (iter->pg && !iter->pg->index)
2480 iter->pg = iter->pg->next;
2489 * ftrace_rec_iter_next, get the next record to process.
2490 * @iter: The handle to the iterator.
2492 * Returns the next iterator after the given iterator @iter.
2494 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2498 if (iter->index >= iter->pg->index) {
2499 iter->pg = iter->pg->next;
2502 /* Could have empty pages */
2503 while (iter->pg && !iter->pg->index)
2504 iter->pg = iter->pg->next;
2514 * ftrace_rec_iter_record, get the record at the iterator location
2515 * @iter: The current iterator location
2517 * Returns the record that the current @iter is at.
2519 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2521 return &iter->pg->records[iter->index];
2525 ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
2529 if (unlikely(ftrace_disabled))
2532 ret = ftrace_init_nop(mod, rec);
2534 ftrace_bug_type = FTRACE_BUG_INIT;
2535 ftrace_bug(ret, rec);
2542 * archs can override this function if they must do something
2543 * before the modifying code is performed.
2545 int __weak ftrace_arch_code_modify_prepare(void)
2551 * archs can override this function if they must do something
2552 * after the modifying code is performed.
2554 int __weak ftrace_arch_code_modify_post_process(void)
2559 void ftrace_modify_all_code(int command)
2561 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2565 if (command & FTRACE_MAY_SLEEP)
2566 mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2569 * If the ftrace_caller calls a ftrace_ops func directly,
2570 * we need to make sure that it only traces functions it
2571 * expects to trace. When doing the switch of functions,
2572 * we need to update to the ftrace_ops_list_func first
2573 * before the transition between old and new calls are set,
2574 * as the ftrace_ops_list_func will check the ops hashes
2575 * to make sure the ops are having the right functions
2579 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2580 if (FTRACE_WARN_ON(err))
2584 if (command & FTRACE_UPDATE_CALLS)
2585 ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2586 else if (command & FTRACE_DISABLE_CALLS)
2587 ftrace_replace_code(mod_flags);
2589 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2590 function_trace_op = set_function_trace_op;
2592 /* If irqs are disabled, we are in stop machine */
2593 if (!irqs_disabled())
2594 smp_call_function(ftrace_sync_ipi, NULL, 1);
2595 err = ftrace_update_ftrace_func(ftrace_trace_function);
2596 if (FTRACE_WARN_ON(err))
2600 if (command & FTRACE_START_FUNC_RET)
2601 err = ftrace_enable_ftrace_graph_caller();
2602 else if (command & FTRACE_STOP_FUNC_RET)
2603 err = ftrace_disable_ftrace_graph_caller();
2604 FTRACE_WARN_ON(err);
2607 static int __ftrace_modify_code(void *data)
2609 int *command = data;
2611 ftrace_modify_all_code(*command);
2617 * ftrace_run_stop_machine, go back to the stop machine method
2618 * @command: The command to tell ftrace what to do
2620 * If an arch needs to fall back to the stop machine method, the
2621 * it can call this function.
2623 void ftrace_run_stop_machine(int command)
2625 stop_machine(__ftrace_modify_code, &command, NULL);
2629 * arch_ftrace_update_code, modify the code to trace or not trace
2630 * @command: The command that needs to be done
2632 * Archs can override this function if it does not need to
2633 * run stop_machine() to modify code.
2635 void __weak arch_ftrace_update_code(int command)
2637 ftrace_run_stop_machine(command);
2640 static void ftrace_run_update_code(int command)
2644 ret = ftrace_arch_code_modify_prepare();
2645 FTRACE_WARN_ON(ret);
2650 * By default we use stop_machine() to modify the code.
2651 * But archs can do what ever they want as long as it
2652 * is safe. The stop_machine() is the safest, but also
2653 * produces the most overhead.
2655 arch_ftrace_update_code(command);
2657 ret = ftrace_arch_code_modify_post_process();
2658 FTRACE_WARN_ON(ret);
2661 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2662 struct ftrace_ops_hash *old_hash)
2664 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2665 ops->old_hash.filter_hash = old_hash->filter_hash;
2666 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2667 ftrace_run_update_code(command);
2668 ops->old_hash.filter_hash = NULL;
2669 ops->old_hash.notrace_hash = NULL;
2670 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2673 static ftrace_func_t saved_ftrace_func;
2674 static int ftrace_start_up;
2676 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2680 static void ftrace_startup_enable(int command)
2682 if (saved_ftrace_func != ftrace_trace_function) {
2683 saved_ftrace_func = ftrace_trace_function;
2684 command |= FTRACE_UPDATE_TRACE_FUNC;
2687 if (!command || !ftrace_enabled)
2690 ftrace_run_update_code(command);
2693 static void ftrace_startup_all(int command)
2695 update_all_ops = true;
2696 ftrace_startup_enable(command);
2697 update_all_ops = false;
2700 int ftrace_startup(struct ftrace_ops *ops, int command)
2704 if (unlikely(ftrace_disabled))
2707 ret = __register_ftrace_function(ops);
2714 * Note that ftrace probes uses this to start up
2715 * and modify functions it will probe. But we still
2716 * set the ADDING flag for modification, as probes
2717 * do not have trampolines. If they add them in the
2718 * future, then the probes will need to distinguish
2719 * between adding and updating probes.
2721 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2723 ret = ftrace_hash_ipmodify_enable(ops);
2725 /* Rollback registration process */
2726 __unregister_ftrace_function(ops);
2728 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2732 if (ftrace_hash_rec_enable(ops, 1))
2733 command |= FTRACE_UPDATE_CALLS;
2735 ftrace_startup_enable(command);
2738 * If ftrace is in an undefined state, we just remove ops from list
2739 * to prevent the NULL pointer, instead of totally rolling it back and
2740 * free trampoline, because those actions could cause further damage.
2742 if (unlikely(ftrace_disabled)) {
2743 __unregister_ftrace_function(ops);
2747 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2752 int ftrace_shutdown(struct ftrace_ops *ops, int command)
2756 if (unlikely(ftrace_disabled))
2759 ret = __unregister_ftrace_function(ops);
2765 * Just warn in case of unbalance, no need to kill ftrace, it's not
2766 * critical but the ftrace_call callers may be never nopped again after
2767 * further ftrace uses.
2769 WARN_ON_ONCE(ftrace_start_up < 0);
2771 /* Disabling ipmodify never fails */
2772 ftrace_hash_ipmodify_disable(ops);
2774 if (ftrace_hash_rec_disable(ops, 1))
2775 command |= FTRACE_UPDATE_CALLS;
2777 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2779 if (saved_ftrace_func != ftrace_trace_function) {
2780 saved_ftrace_func = ftrace_trace_function;
2781 command |= FTRACE_UPDATE_TRACE_FUNC;
2784 if (!command || !ftrace_enabled) {
2786 * If these are dynamic or per_cpu ops, they still
2787 * need their data freed. Since, function tracing is
2788 * not currently active, we can just free them
2789 * without synchronizing all CPUs.
2791 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2798 * If the ops uses a trampoline, then it needs to be
2799 * tested first on update.
2801 ops->flags |= FTRACE_OPS_FL_REMOVING;
2804 /* The trampoline logic checks the old hashes */
2805 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2806 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2808 ftrace_run_update_code(command);
2811 * If there's no more ops registered with ftrace, run a
2812 * sanity check to make sure all rec flags are cleared.
2814 if (rcu_dereference_protected(ftrace_ops_list,
2815 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
2816 struct ftrace_page *pg;
2817 struct dyn_ftrace *rec;
2819 do_for_each_ftrace_rec(pg, rec) {
2820 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
2821 pr_warn(" %pS flags:%lx\n",
2822 (void *)rec->ip, rec->flags);
2823 } while_for_each_ftrace_rec();
2826 ops->old_hash.filter_hash = NULL;
2827 ops->old_hash.notrace_hash = NULL;
2830 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2833 * Dynamic ops may be freed, we must make sure that all
2834 * callers are done before leaving this function.
2835 * The same goes for freeing the per_cpu data of the per_cpu
2838 if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
2840 * We need to do a hard force of sched synchronization.
2841 * This is because we use preempt_disable() to do RCU, but
2842 * the function tracers can be called where RCU is not watching
2843 * (like before user_exit()). We can not rely on the RCU
2844 * infrastructure to do the synchronization, thus we must do it
2847 schedule_on_each_cpu(ftrace_sync);
2850 * When the kernel is preeptive, tasks can be preempted
2851 * while on a ftrace trampoline. Just scheduling a task on
2852 * a CPU is not good enough to flush them. Calling
2853 * synchornize_rcu_tasks() will wait for those tasks to
2854 * execute and either schedule voluntarily or enter user space.
2856 if (IS_ENABLED(CONFIG_PREEMPTION))
2857 synchronize_rcu_tasks();
2860 arch_ftrace_trampoline_free(ops);
2866 static void ftrace_startup_sysctl(void)
2870 if (unlikely(ftrace_disabled))
2873 /* Force update next time */
2874 saved_ftrace_func = NULL;
2875 /* ftrace_start_up is true if we want ftrace running */
2876 if (ftrace_start_up) {
2877 command = FTRACE_UPDATE_CALLS;
2878 if (ftrace_graph_active)
2879 command |= FTRACE_START_FUNC_RET;
2880 ftrace_startup_enable(command);
2884 static void ftrace_shutdown_sysctl(void)
2888 if (unlikely(ftrace_disabled))
2891 /* ftrace_start_up is true if ftrace is running */
2892 if (ftrace_start_up) {
2893 command = FTRACE_DISABLE_CALLS;
2894 if (ftrace_graph_active)
2895 command |= FTRACE_STOP_FUNC_RET;
2896 ftrace_run_update_code(command);
2900 static u64 ftrace_update_time;
2901 unsigned long ftrace_update_tot_cnt;
2902 unsigned long ftrace_number_of_pages;
2903 unsigned long ftrace_number_of_groups;
2905 static inline int ops_traces_mod(struct ftrace_ops *ops)
2908 * Filter_hash being empty will default to trace module.
2909 * But notrace hash requires a test of individual module functions.
2911 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
2912 ftrace_hash_empty(ops->func_hash->notrace_hash);
2916 * Check if the current ops references the record.
2918 * If the ops traces all functions, then it was already accounted for.
2919 * If the ops does not trace the current record function, skip it.
2920 * If the ops ignores the function via notrace filter, skip it.
2923 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2925 /* If ops isn't enabled, ignore it */
2926 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2929 /* If ops traces all then it includes this function */
2930 if (ops_traces_mod(ops))
2933 /* The function must be in the filter */
2934 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
2935 !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
2938 /* If in notrace hash, we ignore it too */
2939 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
2945 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
2947 struct ftrace_page *pg;
2948 struct dyn_ftrace *p;
2950 unsigned long update_cnt = 0;
2951 unsigned long rec_flags = 0;
2954 start = ftrace_now(raw_smp_processor_id());
2957 * When a module is loaded, this function is called to convert
2958 * the calls to mcount in its text to nops, and also to create
2959 * an entry in the ftrace data. Now, if ftrace is activated
2960 * after this call, but before the module sets its text to
2961 * read-only, the modification of enabling ftrace can fail if
2962 * the read-only is done while ftrace is converting the calls.
2963 * To prevent this, the module's records are set as disabled
2964 * and will be enabled after the call to set the module's text
2968 rec_flags |= FTRACE_FL_DISABLED;
2970 for (pg = new_pgs; pg; pg = pg->next) {
2972 for (i = 0; i < pg->index; i++) {
2974 /* If something went wrong, bail without enabling anything */
2975 if (unlikely(ftrace_disabled))
2978 p = &pg->records[i];
2979 p->flags = rec_flags;
2982 * Do the initial record conversion from mcount jump
2983 * to the NOP instructions.
2985 if (!__is_defined(CC_USING_NOP_MCOUNT) &&
2986 !ftrace_nop_initialize(mod, p))
2993 stop = ftrace_now(raw_smp_processor_id());
2994 ftrace_update_time = stop - start;
2995 ftrace_update_tot_cnt += update_cnt;
3000 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3005 if (WARN_ON(!count))
3008 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
3011 * We want to fill as much as possible. No more than a page
3014 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
3018 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3021 /* if we can't allocate this size, try something smaller */
3028 ftrace_number_of_pages += 1 << order;
3029 ftrace_number_of_groups++;
3031 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3040 static void ftrace_free_pages(struct ftrace_page *pages)
3042 struct ftrace_page *pg = pages;
3046 free_pages((unsigned long)pg->records, pg->order);
3047 ftrace_number_of_pages -= 1 << pg->order;
3052 ftrace_number_of_groups--;
3056 static struct ftrace_page *
3057 ftrace_allocate_pages(unsigned long num_to_init)
3059 struct ftrace_page *start_pg;
3060 struct ftrace_page *pg;
3066 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3071 * Try to allocate as much as possible in one continues
3072 * location that fills in all of the space. We want to
3073 * waste as little space as possible.
3076 cnt = ftrace_allocate_records(pg, num_to_init);
3084 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3094 ftrace_free_pages(start_pg);
3095 pr_info("ftrace: FAILED to allocate memory for functions\n");
3099 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3101 struct ftrace_iterator {
3105 struct ftrace_page *pg;
3106 struct dyn_ftrace *func;
3107 struct ftrace_func_probe *probe;
3108 struct ftrace_func_entry *probe_entry;
3109 struct trace_parser parser;
3110 struct ftrace_hash *hash;
3111 struct ftrace_ops *ops;
3112 struct trace_array *tr;
3113 struct list_head *mod_list;
3120 t_probe_next(struct seq_file *m, loff_t *pos)
3122 struct ftrace_iterator *iter = m->private;
3123 struct trace_array *tr = iter->ops->private;
3124 struct list_head *func_probes;
3125 struct ftrace_hash *hash;
3126 struct list_head *next;
3127 struct hlist_node *hnd = NULL;
3128 struct hlist_head *hhd;
3137 func_probes = &tr->func_probes;
3138 if (list_empty(func_probes))
3142 next = func_probes->next;
3143 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3146 if (iter->probe_entry)
3147 hnd = &iter->probe_entry->hlist;
3149 hash = iter->probe->ops.func_hash->filter_hash;
3152 * A probe being registered may temporarily have an empty hash
3153 * and it's at the end of the func_probes list.
3155 if (!hash || hash == EMPTY_HASH)
3158 size = 1 << hash->size_bits;
3161 if (iter->pidx >= size) {
3162 if (iter->probe->list.next == func_probes)
3164 next = iter->probe->list.next;
3165 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3166 hash = iter->probe->ops.func_hash->filter_hash;
3167 size = 1 << hash->size_bits;
3171 hhd = &hash->buckets[iter->pidx];
3173 if (hlist_empty(hhd)) {
3189 if (WARN_ON_ONCE(!hnd))
3192 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3197 static void *t_probe_start(struct seq_file *m, loff_t *pos)
3199 struct ftrace_iterator *iter = m->private;
3203 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3206 if (iter->mod_pos > *pos)
3210 iter->probe_entry = NULL;
3212 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3213 p = t_probe_next(m, &l);
3220 /* Only set this if we have an item */
3221 iter->flags |= FTRACE_ITER_PROBE;
3227 t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3229 struct ftrace_func_entry *probe_entry;
3230 struct ftrace_probe_ops *probe_ops;
3231 struct ftrace_func_probe *probe;
3233 probe = iter->probe;
3234 probe_entry = iter->probe_entry;
3236 if (WARN_ON_ONCE(!probe || !probe_entry))
3239 probe_ops = probe->probe_ops;
3241 if (probe_ops->print)
3242 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3244 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3245 (void *)probe_ops->func);
3251 t_mod_next(struct seq_file *m, loff_t *pos)
3253 struct ftrace_iterator *iter = m->private;
3254 struct trace_array *tr = iter->tr;
3259 iter->mod_list = iter->mod_list->next;
3261 if (iter->mod_list == &tr->mod_trace ||
3262 iter->mod_list == &tr->mod_notrace) {
3263 iter->flags &= ~FTRACE_ITER_MOD;
3267 iter->mod_pos = *pos;
3272 static void *t_mod_start(struct seq_file *m, loff_t *pos)
3274 struct ftrace_iterator *iter = m->private;
3278 if (iter->func_pos > *pos)
3281 iter->mod_pos = iter->func_pos;
3283 /* probes are only available if tr is set */
3287 for (l = 0; l <= (*pos - iter->func_pos); ) {
3288 p = t_mod_next(m, &l);
3293 iter->flags &= ~FTRACE_ITER_MOD;
3294 return t_probe_start(m, pos);
3297 /* Only set this if we have an item */
3298 iter->flags |= FTRACE_ITER_MOD;
3304 t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3306 struct ftrace_mod_load *ftrace_mod;
3307 struct trace_array *tr = iter->tr;
3309 if (WARN_ON_ONCE(!iter->mod_list) ||
3310 iter->mod_list == &tr->mod_trace ||
3311 iter->mod_list == &tr->mod_notrace)
3314 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3316 if (ftrace_mod->func)
3317 seq_printf(m, "%s", ftrace_mod->func);
3321 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3327 t_func_next(struct seq_file *m, loff_t *pos)
3329 struct ftrace_iterator *iter = m->private;
3330 struct dyn_ftrace *rec = NULL;
3335 if (iter->idx >= iter->pg->index) {
3336 if (iter->pg->next) {
3337 iter->pg = iter->pg->next;
3342 rec = &iter->pg->records[iter->idx++];
3343 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3344 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3346 ((iter->flags & FTRACE_ITER_ENABLED) &&
3347 !(rec->flags & FTRACE_FL_ENABLED))) {
3357 iter->pos = iter->func_pos = *pos;
3364 t_next(struct seq_file *m, void *v, loff_t *pos)
3366 struct ftrace_iterator *iter = m->private;
3367 loff_t l = *pos; /* t_probe_start() must use original pos */
3370 if (unlikely(ftrace_disabled))
3373 if (iter->flags & FTRACE_ITER_PROBE)
3374 return t_probe_next(m, pos);
3376 if (iter->flags & FTRACE_ITER_MOD)
3377 return t_mod_next(m, pos);
3379 if (iter->flags & FTRACE_ITER_PRINTALL) {
3380 /* next must increment pos, and t_probe_start does not */
3382 return t_mod_start(m, &l);
3385 ret = t_func_next(m, pos);
3388 return t_mod_start(m, &l);
3393 static void reset_iter_read(struct ftrace_iterator *iter)
3397 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3400 static void *t_start(struct seq_file *m, loff_t *pos)
3402 struct ftrace_iterator *iter = m->private;
3406 mutex_lock(&ftrace_lock);
3408 if (unlikely(ftrace_disabled))
3412 * If an lseek was done, then reset and start from beginning.
3414 if (*pos < iter->pos)
3415 reset_iter_read(iter);
3418 * For set_ftrace_filter reading, if we have the filter
3419 * off, we can short cut and just print out that all
3420 * functions are enabled.
3422 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3423 ftrace_hash_empty(iter->hash)) {
3424 iter->func_pos = 1; /* Account for the message */
3426 return t_mod_start(m, pos);
3427 iter->flags |= FTRACE_ITER_PRINTALL;
3428 /* reset in case of seek/pread */
3429 iter->flags &= ~FTRACE_ITER_PROBE;
3433 if (iter->flags & FTRACE_ITER_MOD)
3434 return t_mod_start(m, pos);
3437 * Unfortunately, we need to restart at ftrace_pages_start
3438 * every time we let go of the ftrace_mutex. This is because
3439 * those pointers can change without the lock.
3441 iter->pg = ftrace_pages_start;
3443 for (l = 0; l <= *pos; ) {
3444 p = t_func_next(m, &l);
3450 return t_mod_start(m, pos);
3455 static void t_stop(struct seq_file *m, void *p)
3457 mutex_unlock(&ftrace_lock);
3461 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3466 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3467 struct dyn_ftrace *rec)
3471 ptr = arch_ftrace_trampoline_func(ops, rec);
3473 seq_printf(m, " ->%pS", ptr);
3476 static int t_show(struct seq_file *m, void *v)
3478 struct ftrace_iterator *iter = m->private;
3479 struct dyn_ftrace *rec;
3481 if (iter->flags & FTRACE_ITER_PROBE)
3482 return t_probe_show(m, iter);
3484 if (iter->flags & FTRACE_ITER_MOD)
3485 return t_mod_show(m, iter);
3487 if (iter->flags & FTRACE_ITER_PRINTALL) {
3488 if (iter->flags & FTRACE_ITER_NOTRACE)
3489 seq_puts(m, "#### no functions disabled ####\n");
3491 seq_puts(m, "#### all functions enabled ####\n");
3500 seq_printf(m, "%ps", (void *)rec->ip);
3501 if (iter->flags & FTRACE_ITER_ENABLED) {
3502 struct ftrace_ops *ops;
3504 seq_printf(m, " (%ld)%s%s",
3505 ftrace_rec_count(rec),
3506 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3507 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ");
3508 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3509 ops = ftrace_find_tramp_ops_any(rec);
3512 seq_printf(m, "\ttramp: %pS (%pS)",
3513 (void *)ops->trampoline,
3515 add_trampoline_func(m, ops, rec);
3516 ops = ftrace_find_tramp_ops_next(rec, ops);
3519 seq_puts(m, "\ttramp: ERROR!");
3521 add_trampoline_func(m, NULL, rec);
3530 static const struct seq_operations show_ftrace_seq_ops = {
3538 ftrace_avail_open(struct inode *inode, struct file *file)
3540 struct ftrace_iterator *iter;
3543 ret = security_locked_down(LOCKDOWN_TRACEFS);
3547 if (unlikely(ftrace_disabled))
3550 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3554 iter->pg = ftrace_pages_start;
3555 iter->ops = &global_ops;
3561 ftrace_enabled_open(struct inode *inode, struct file *file)
3563 struct ftrace_iterator *iter;
3566 * This shows us what functions are currently being
3567 * traced and by what. Not sure if we want lockdown
3568 * to hide such critical information for an admin.
3569 * Although, perhaps it can show information we don't
3570 * want people to see, but if something is tracing
3571 * something, we probably want to know about it.
3574 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3578 iter->pg = ftrace_pages_start;
3579 iter->flags = FTRACE_ITER_ENABLED;
3580 iter->ops = &global_ops;
3586 * ftrace_regex_open - initialize function tracer filter files
3587 * @ops: The ftrace_ops that hold the hash filters
3588 * @flag: The type of filter to process
3589 * @inode: The inode, usually passed in to your open routine
3590 * @file: The file, usually passed in to your open routine
3592 * ftrace_regex_open() initializes the filter files for the
3593 * @ops. Depending on @flag it may process the filter hash or
3594 * the notrace hash of @ops. With this called from the open
3595 * routine, you can use ftrace_filter_write() for the write
3596 * routine if @flag has FTRACE_ITER_FILTER set, or
3597 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3598 * tracing_lseek() should be used as the lseek routine, and
3599 * release must call ftrace_regex_release().
3602 ftrace_regex_open(struct ftrace_ops *ops, int flag,
3603 struct inode *inode, struct file *file)
3605 struct ftrace_iterator *iter;
3606 struct ftrace_hash *hash;
3607 struct list_head *mod_head;
3608 struct trace_array *tr = ops->private;
3611 ftrace_ops_init(ops);
3613 if (unlikely(ftrace_disabled))
3616 if (tracing_check_open_get_tr(tr))
3619 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3623 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
3630 mutex_lock(&ops->func_hash->regex_lock);
3632 if (flag & FTRACE_ITER_NOTRACE) {
3633 hash = ops->func_hash->notrace_hash;
3634 mod_head = tr ? &tr->mod_notrace : NULL;
3636 hash = ops->func_hash->filter_hash;
3637 mod_head = tr ? &tr->mod_trace : NULL;
3640 iter->mod_list = mod_head;
3642 if (file->f_mode & FMODE_WRITE) {
3643 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3645 if (file->f_flags & O_TRUNC) {
3646 iter->hash = alloc_ftrace_hash(size_bits);
3647 clear_ftrace_mod_list(mod_head);
3649 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3653 trace_parser_put(&iter->parser);
3661 if (file->f_mode & FMODE_READ) {
3662 iter->pg = ftrace_pages_start;
3664 ret = seq_open(file, &show_ftrace_seq_ops);
3666 struct seq_file *m = file->private_data;
3670 free_ftrace_hash(iter->hash);
3671 trace_parser_put(&iter->parser);
3674 file->private_data = iter;
3677 mutex_unlock(&ops->func_hash->regex_lock);
3683 trace_array_put(tr);
3690 ftrace_filter_open(struct inode *inode, struct file *file)
3692 struct ftrace_ops *ops = inode->i_private;
3694 /* Checks for tracefs lockdown */
3695 return ftrace_regex_open(ops,
3696 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3701 ftrace_notrace_open(struct inode *inode, struct file *file)
3703 struct ftrace_ops *ops = inode->i_private;
3705 /* Checks for tracefs lockdown */
3706 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3710 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3711 struct ftrace_glob {
3718 * If symbols in an architecture don't correspond exactly to the user-visible
3719 * name of what they represent, it is possible to define this function to
3720 * perform the necessary adjustments.
3722 char * __weak arch_ftrace_match_adjust(char *str, const char *search)
3727 static int ftrace_match(char *str, struct ftrace_glob *g)
3732 str = arch_ftrace_match_adjust(str, g->search);
3736 if (strcmp(str, g->search) == 0)
3739 case MATCH_FRONT_ONLY:
3740 if (strncmp(str, g->search, g->len) == 0)
3743 case MATCH_MIDDLE_ONLY:
3744 if (strstr(str, g->search))
3747 case MATCH_END_ONLY:
3749 if (slen >= g->len &&
3750 memcmp(str + slen - g->len, g->search, g->len) == 0)
3754 if (glob_match(g->search, str))
3763 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3765 struct ftrace_func_entry *entry;
3768 entry = ftrace_lookup_ip(hash, rec->ip);
3770 /* Do nothing if it doesn't exist */
3774 free_hash_entry(hash, entry);
3776 /* Do nothing if it exists */
3780 ret = add_hash_entry(hash, rec->ip);
3786 add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
3789 long index = simple_strtoul(func_g->search, NULL, 0);
3790 struct ftrace_page *pg;
3791 struct dyn_ftrace *rec;
3793 /* The index starts at 1 */
3797 do_for_each_ftrace_rec(pg, rec) {
3798 if (pg->index <= index) {
3800 /* this is a double loop, break goes to the next page */
3803 rec = &pg->records[index];
3804 enter_record(hash, rec, clear_filter);
3806 } while_for_each_ftrace_rec();
3811 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3812 struct ftrace_glob *mod_g, int exclude_mod)
3814 char str[KSYM_SYMBOL_LEN];
3817 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3820 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3822 /* blank module name to match all modules */
3824 /* blank module globbing: modname xor exclude_mod */
3825 if (!exclude_mod != !modname)
3831 * exclude_mod is set to trace everything but the given
3832 * module. If it is set and the module matches, then
3833 * return 0. If it is not set, and the module doesn't match
3834 * also return 0. Otherwise, check the function to see if
3837 if (!mod_matches == !exclude_mod)
3840 /* blank search means to match all funcs in the mod */
3845 return ftrace_match(str, func_g);
3849 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
3851 struct ftrace_page *pg;
3852 struct dyn_ftrace *rec;
3853 struct ftrace_glob func_g = { .type = MATCH_FULL };
3854 struct ftrace_glob mod_g = { .type = MATCH_FULL };
3855 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
3856 int exclude_mod = 0;
3859 int clear_filter = 0;
3862 func_g.type = filter_parse_regex(func, len, &func_g.search,
3864 func_g.len = strlen(func_g.search);
3868 mod_g.type = filter_parse_regex(mod, strlen(mod),
3869 &mod_g.search, &exclude_mod);
3870 mod_g.len = strlen(mod_g.search);
3873 mutex_lock(&ftrace_lock);
3875 if (unlikely(ftrace_disabled))
3878 if (func_g.type == MATCH_INDEX) {
3879 found = add_rec_by_index(hash, &func_g, clear_filter);
3883 do_for_each_ftrace_rec(pg, rec) {
3885 if (rec->flags & FTRACE_FL_DISABLED)
3888 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
3889 ret = enter_record(hash, rec, clear_filter);
3896 } while_for_each_ftrace_rec();
3898 mutex_unlock(&ftrace_lock);
3904 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
3906 return match_records(hash, buff, len, NULL);
3909 static void ftrace_ops_update_code(struct ftrace_ops *ops,
3910 struct ftrace_ops_hash *old_hash)
3912 struct ftrace_ops *op;
3914 if (!ftrace_enabled)
3917 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
3918 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
3923 * If this is the shared global_ops filter, then we need to
3924 * check if there is another ops that shares it, is enabled.
3925 * If so, we still need to run the modify code.
3927 if (ops->func_hash != &global_ops.local_hash)
3930 do_for_each_ftrace_op(op, ftrace_ops_list) {
3931 if (op->func_hash == &global_ops.local_hash &&
3932 op->flags & FTRACE_OPS_FL_ENABLED) {
3933 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
3934 /* Only need to do this once */
3937 } while_for_each_ftrace_op(op);
3940 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
3941 struct ftrace_hash **orig_hash,
3942 struct ftrace_hash *hash,
3945 struct ftrace_ops_hash old_hash_ops;
3946 struct ftrace_hash *old_hash;
3949 old_hash = *orig_hash;
3950 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
3951 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
3952 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3954 ftrace_ops_update_code(ops, &old_hash_ops);
3955 free_ftrace_hash_rcu(old_hash);
3960 static bool module_exists(const char *module)
3962 /* All modules have the symbol __this_module */
3963 static const char this_mod[] = "__this_module";
3964 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
3968 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
3970 if (n > sizeof(modname) - 1)
3973 val = module_kallsyms_lookup_name(modname);
3977 static int cache_mod(struct trace_array *tr,
3978 const char *func, char *module, int enable)
3980 struct ftrace_mod_load *ftrace_mod, *n;
3981 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
3984 mutex_lock(&ftrace_lock);
3986 /* We do not cache inverse filters */
3987 if (func[0] == '!') {
3991 /* Look to remove this hash */
3992 list_for_each_entry_safe(ftrace_mod, n, head, list) {
3993 if (strcmp(ftrace_mod->module, module) != 0)
3996 /* no func matches all */
3997 if (strcmp(func, "*") == 0 ||
3998 (ftrace_mod->func &&
3999 strcmp(ftrace_mod->func, func) == 0)) {
4001 free_ftrace_mod(ftrace_mod);
4009 /* We only care about modules that have not been loaded yet */
4010 if (module_exists(module))
4013 /* Save this string off, and execute it when the module is loaded */
4014 ret = ftrace_add_mod(tr, func, module, enable);
4016 mutex_unlock(&ftrace_lock);
4022 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4023 int reset, int enable);
4025 #ifdef CONFIG_MODULES
4026 static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4027 char *mod, bool enable)
4029 struct ftrace_mod_load *ftrace_mod, *n;
4030 struct ftrace_hash **orig_hash, *new_hash;
4031 LIST_HEAD(process_mods);
4035 mutex_lock(&ops->func_hash->regex_lock);
4038 orig_hash = &ops->func_hash->filter_hash;
4040 orig_hash = &ops->func_hash->notrace_hash;
4042 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4045 goto out; /* warn? */
4047 mutex_lock(&ftrace_lock);
4049 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4051 if (strcmp(ftrace_mod->module, mod) != 0)
4054 if (ftrace_mod->func)
4055 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4057 func = kstrdup("*", GFP_KERNEL);
4059 if (!func) /* warn? */
4062 list_del(&ftrace_mod->list);
4063 list_add(&ftrace_mod->list, &process_mods);
4065 /* Use the newly allocated func, as it may be "*" */
4066 kfree(ftrace_mod->func);
4067 ftrace_mod->func = func;
4070 mutex_unlock(&ftrace_lock);
4072 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4074 func = ftrace_mod->func;
4076 /* Grabs ftrace_lock, which is why we have this extra step */
4077 match_records(new_hash, func, strlen(func), mod);
4078 free_ftrace_mod(ftrace_mod);
4081 if (enable && list_empty(head))
4082 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4084 mutex_lock(&ftrace_lock);
4086 ret = ftrace_hash_move_and_update_ops(ops, orig_hash,
4088 mutex_unlock(&ftrace_lock);
4091 mutex_unlock(&ops->func_hash->regex_lock);
4093 free_ftrace_hash(new_hash);
4096 static void process_cached_mods(const char *mod_name)
4098 struct trace_array *tr;
4101 mod = kstrdup(mod_name, GFP_KERNEL);
4105 mutex_lock(&trace_types_lock);
4106 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4107 if (!list_empty(&tr->mod_trace))
4108 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4109 if (!list_empty(&tr->mod_notrace))
4110 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4112 mutex_unlock(&trace_types_lock);
4119 * We register the module command as a template to show others how
4120 * to register the a command as well.
4124 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4125 char *func_orig, char *cmd, char *module, int enable)
4130 /* match_records() modifies func, and we need the original */
4131 func = kstrdup(func_orig, GFP_KERNEL);
4136 * cmd == 'mod' because we only registered this func
4137 * for the 'mod' ftrace_func_command.
4138 * But if you register one func with multiple commands,
4139 * you can tell which command was used by the cmd
4142 ret = match_records(hash, func, strlen(func), module);
4146 return cache_mod(tr, func_orig, module, enable);
4152 static struct ftrace_func_command ftrace_mod_cmd = {
4154 .func = ftrace_mod_callback,
4157 static int __init ftrace_mod_cmd_init(void)
4159 return register_ftrace_command(&ftrace_mod_cmd);
4161 core_initcall(ftrace_mod_cmd_init);
4163 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4164 struct ftrace_ops *op, struct pt_regs *pt_regs)
4166 struct ftrace_probe_ops *probe_ops;
4167 struct ftrace_func_probe *probe;
4169 probe = container_of(op, struct ftrace_func_probe, ops);
4170 probe_ops = probe->probe_ops;
4173 * Disable preemption for these calls to prevent a RCU grace
4174 * period. This syncs the hash iteration and freeing of items
4175 * on the hash. rcu_read_lock is too dangerous here.
4177 preempt_disable_notrace();
4178 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4179 preempt_enable_notrace();
4182 struct ftrace_func_map {
4183 struct ftrace_func_entry entry;
4187 struct ftrace_func_mapper {
4188 struct ftrace_hash hash;
4192 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4194 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4196 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4198 struct ftrace_hash *hash;
4201 * The mapper is simply a ftrace_hash, but since the entries
4202 * in the hash are not ftrace_func_entry type, we define it
4203 * as a separate structure.
4205 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4206 return (struct ftrace_func_mapper *)hash;
4210 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4211 * @mapper: The mapper that has the ip maps
4212 * @ip: the instruction pointer to find the data for
4214 * Returns the data mapped to @ip if found otherwise NULL. The return
4215 * is actually the address of the mapper data pointer. The address is
4216 * returned for use cases where the data is no bigger than a long, and
4217 * the user can use the data pointer as its data instead of having to
4218 * allocate more memory for the reference.
4220 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4223 struct ftrace_func_entry *entry;
4224 struct ftrace_func_map *map;
4226 entry = ftrace_lookup_ip(&mapper->hash, ip);
4230 map = (struct ftrace_func_map *)entry;
4235 * ftrace_func_mapper_add_ip - Map some data to an ip
4236 * @mapper: The mapper that has the ip maps
4237 * @ip: The instruction pointer address to map @data to
4238 * @data: The data to map to @ip
4240 * Returns 0 on succes otherwise an error.
4242 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4243 unsigned long ip, void *data)
4245 struct ftrace_func_entry *entry;
4246 struct ftrace_func_map *map;
4248 entry = ftrace_lookup_ip(&mapper->hash, ip);
4252 map = kmalloc(sizeof(*map), GFP_KERNEL);
4259 __add_hash_entry(&mapper->hash, &map->entry);
4265 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4266 * @mapper: The mapper that has the ip maps
4267 * @ip: The instruction pointer address to remove the data from
4269 * Returns the data if it is found, otherwise NULL.
4270 * Note, if the data pointer is used as the data itself, (see
4271 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4272 * if the data pointer was set to zero.
4274 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4277 struct ftrace_func_entry *entry;
4278 struct ftrace_func_map *map;
4281 entry = ftrace_lookup_ip(&mapper->hash, ip);
4285 map = (struct ftrace_func_map *)entry;
4288 remove_hash_entry(&mapper->hash, entry);
4295 * free_ftrace_func_mapper - free a mapping of ips and data
4296 * @mapper: The mapper that has the ip maps
4297 * @free_func: A function to be called on each data item.
4299 * This is used to free the function mapper. The @free_func is optional
4300 * and can be used if the data needs to be freed as well.
4302 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4303 ftrace_mapper_func free_func)
4305 struct ftrace_func_entry *entry;
4306 struct ftrace_func_map *map;
4307 struct hlist_head *hhd;
4313 if (free_func && mapper->hash.count) {
4314 size = 1 << mapper->hash.size_bits;
4315 for (i = 0; i < size; i++) {
4316 hhd = &mapper->hash.buckets[i];
4317 hlist_for_each_entry(entry, hhd, hlist) {
4318 map = (struct ftrace_func_map *)entry;
4323 free_ftrace_hash(&mapper->hash);
4326 static void release_probe(struct ftrace_func_probe *probe)
4328 struct ftrace_probe_ops *probe_ops;
4330 mutex_lock(&ftrace_lock);
4332 WARN_ON(probe->ref <= 0);
4334 /* Subtract the ref that was used to protect this instance */
4338 probe_ops = probe->probe_ops;
4340 * Sending zero as ip tells probe_ops to free
4341 * the probe->data itself
4343 if (probe_ops->free)
4344 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4345 list_del(&probe->list);
4348 mutex_unlock(&ftrace_lock);
4351 static void acquire_probe_locked(struct ftrace_func_probe *probe)
4354 * Add one ref to keep it from being freed when releasing the
4355 * ftrace_lock mutex.
4361 register_ftrace_function_probe(char *glob, struct trace_array *tr,
4362 struct ftrace_probe_ops *probe_ops,
4365 struct ftrace_func_entry *entry;
4366 struct ftrace_func_probe *probe;
4367 struct ftrace_hash **orig_hash;
4368 struct ftrace_hash *old_hash;
4369 struct ftrace_hash *hash;
4378 /* We do not support '!' for function probes */
4379 if (WARN_ON(glob[0] == '!'))
4383 mutex_lock(&ftrace_lock);
4384 /* Check if the probe_ops is already registered */
4385 list_for_each_entry(probe, &tr->func_probes, list) {
4386 if (probe->probe_ops == probe_ops)
4389 if (&probe->list == &tr->func_probes) {
4390 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4392 mutex_unlock(&ftrace_lock);
4395 probe->probe_ops = probe_ops;
4396 probe->ops.func = function_trace_probe_call;
4398 ftrace_ops_init(&probe->ops);
4399 list_add(&probe->list, &tr->func_probes);
4402 acquire_probe_locked(probe);
4404 mutex_unlock(&ftrace_lock);
4407 * Note, there's a small window here that the func_hash->filter_hash
4408 * may be NULL or empty. Need to be carefule when reading the loop.
4410 mutex_lock(&probe->ops.func_hash->regex_lock);
4412 orig_hash = &probe->ops.func_hash->filter_hash;
4413 old_hash = *orig_hash;
4414 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4421 ret = ftrace_match_records(hash, glob, strlen(glob));
4423 /* Nothing found? */
4430 size = 1 << hash->size_bits;
4431 for (i = 0; i < size; i++) {
4432 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4433 if (ftrace_lookup_ip(old_hash, entry->ip))
4436 * The caller might want to do something special
4437 * for each function we find. We call the callback
4438 * to give the caller an opportunity to do so.
4440 if (probe_ops->init) {
4441 ret = probe_ops->init(probe_ops, tr,
4445 if (probe_ops->free && count)
4446 probe_ops->free(probe_ops, tr,
4456 mutex_lock(&ftrace_lock);
4459 /* Nothing was added? */
4464 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4469 /* One ref for each new function traced */
4470 probe->ref += count;
4472 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4473 ret = ftrace_startup(&probe->ops, 0);
4476 mutex_unlock(&ftrace_lock);
4481 mutex_unlock(&probe->ops.func_hash->regex_lock);
4482 free_ftrace_hash(hash);
4484 release_probe(probe);
4489 if (!probe_ops->free || !count)
4492 /* Failed to do the move, need to call the free functions */
4493 for (i = 0; i < size; i++) {
4494 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4495 if (ftrace_lookup_ip(old_hash, entry->ip))
4497 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4504 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4505 struct ftrace_probe_ops *probe_ops)
4507 struct ftrace_ops_hash old_hash_ops;
4508 struct ftrace_func_entry *entry;
4509 struct ftrace_func_probe *probe;
4510 struct ftrace_glob func_g;
4511 struct ftrace_hash **orig_hash;
4512 struct ftrace_hash *old_hash;
4513 struct ftrace_hash *hash = NULL;
4514 struct hlist_node *tmp;
4515 struct hlist_head hhd;
4516 char str[KSYM_SYMBOL_LEN];
4518 int i, ret = -ENODEV;
4521 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4522 func_g.search = NULL;
4526 func_g.type = filter_parse_regex(glob, strlen(glob),
4527 &func_g.search, ¬);
4528 func_g.len = strlen(func_g.search);
4530 /* we do not support '!' for function probes */
4535 mutex_lock(&ftrace_lock);
4536 /* Check if the probe_ops is already registered */
4537 list_for_each_entry(probe, &tr->func_probes, list) {
4538 if (probe->probe_ops == probe_ops)
4541 if (&probe->list == &tr->func_probes)
4542 goto err_unlock_ftrace;
4545 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4546 goto err_unlock_ftrace;
4548 acquire_probe_locked(probe);
4550 mutex_unlock(&ftrace_lock);
4552 mutex_lock(&probe->ops.func_hash->regex_lock);
4554 orig_hash = &probe->ops.func_hash->filter_hash;
4555 old_hash = *orig_hash;
4557 if (ftrace_hash_empty(old_hash))
4560 old_hash_ops.filter_hash = old_hash;
4561 /* Probes only have filters */
4562 old_hash_ops.notrace_hash = NULL;
4565 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4569 INIT_HLIST_HEAD(&hhd);
4571 size = 1 << hash->size_bits;
4572 for (i = 0; i < size; i++) {
4573 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4575 if (func_g.search) {
4576 kallsyms_lookup(entry->ip, NULL, NULL,
4578 if (!ftrace_match(str, &func_g))
4582 remove_hash_entry(hash, entry);
4583 hlist_add_head(&entry->hlist, &hhd);
4587 /* Nothing found? */
4593 mutex_lock(&ftrace_lock);
4595 WARN_ON(probe->ref < count);
4597 probe->ref -= count;
4599 if (ftrace_hash_empty(hash))
4600 ftrace_shutdown(&probe->ops, 0);
4602 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4605 /* still need to update the function call sites */
4606 if (ftrace_enabled && !ftrace_hash_empty(hash))
4607 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4611 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4612 hlist_del(&entry->hlist);
4613 if (probe_ops->free)
4614 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4617 mutex_unlock(&ftrace_lock);
4620 mutex_unlock(&probe->ops.func_hash->regex_lock);
4621 free_ftrace_hash(hash);
4623 release_probe(probe);
4628 mutex_unlock(&ftrace_lock);
4632 void clear_ftrace_function_probes(struct trace_array *tr)
4634 struct ftrace_func_probe *probe, *n;
4636 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4637 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
4640 static LIST_HEAD(ftrace_commands);
4641 static DEFINE_MUTEX(ftrace_cmd_mutex);
4644 * Currently we only register ftrace commands from __init, so mark this
4647 __init int register_ftrace_command(struct ftrace_func_command *cmd)
4649 struct ftrace_func_command *p;
4652 mutex_lock(&ftrace_cmd_mutex);
4653 list_for_each_entry(p, &ftrace_commands, list) {
4654 if (strcmp(cmd->name, p->name) == 0) {
4659 list_add(&cmd->list, &ftrace_commands);
4661 mutex_unlock(&ftrace_cmd_mutex);
4667 * Currently we only unregister ftrace commands from __init, so mark
4670 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4672 struct ftrace_func_command *p, *n;
4675 mutex_lock(&ftrace_cmd_mutex);
4676 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4677 if (strcmp(cmd->name, p->name) == 0) {
4679 list_del_init(&p->list);
4684 mutex_unlock(&ftrace_cmd_mutex);
4689 static int ftrace_process_regex(struct ftrace_iterator *iter,
4690 char *buff, int len, int enable)
4692 struct ftrace_hash *hash = iter->hash;
4693 struct trace_array *tr = iter->ops->private;
4694 char *func, *command, *next = buff;
4695 struct ftrace_func_command *p;
4698 func = strsep(&next, ":");
4701 ret = ftrace_match_records(hash, func, len);
4711 command = strsep(&next, ":");
4713 mutex_lock(&ftrace_cmd_mutex);
4714 list_for_each_entry(p, &ftrace_commands, list) {
4715 if (strcmp(p->name, command) == 0) {
4716 ret = p->func(tr, hash, func, command, next, enable);
4721 mutex_unlock(&ftrace_cmd_mutex);
4727 ftrace_regex_write(struct file *file, const char __user *ubuf,
4728 size_t cnt, loff_t *ppos, int enable)
4730 struct ftrace_iterator *iter;
4731 struct trace_parser *parser;
4737 if (file->f_mode & FMODE_READ) {
4738 struct seq_file *m = file->private_data;
4741 iter = file->private_data;
4743 if (unlikely(ftrace_disabled))
4746 /* iter->hash is a local copy, so we don't need regex_lock */
4748 parser = &iter->parser;
4749 read = trace_get_user(parser, ubuf, cnt, ppos);
4751 if (read >= 0 && trace_parser_loaded(parser) &&
4752 !trace_parser_cont(parser)) {
4753 ret = ftrace_process_regex(iter, parser->buffer,
4754 parser->idx, enable);
4755 trace_parser_clear(parser);
4766 ftrace_filter_write(struct file *file, const char __user *ubuf,
4767 size_t cnt, loff_t *ppos)
4769 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4773 ftrace_notrace_write(struct file *file, const char __user *ubuf,
4774 size_t cnt, loff_t *ppos)
4776 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4780 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4782 struct ftrace_func_entry *entry;
4784 if (!ftrace_location(ip))
4788 entry = ftrace_lookup_ip(hash, ip);
4791 free_hash_entry(hash, entry);
4795 return add_hash_entry(hash, ip);
4799 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4800 unsigned long ip, int remove, int reset, int enable)
4802 struct ftrace_hash **orig_hash;
4803 struct ftrace_hash *hash;
4806 if (unlikely(ftrace_disabled))
4809 mutex_lock(&ops->func_hash->regex_lock);
4812 orig_hash = &ops->func_hash->filter_hash;
4814 orig_hash = &ops->func_hash->notrace_hash;
4817 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4819 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4823 goto out_regex_unlock;
4826 if (buf && !ftrace_match_records(hash, buf, len)) {
4828 goto out_regex_unlock;
4831 ret = ftrace_match_addr(hash, ip, remove);
4833 goto out_regex_unlock;
4836 mutex_lock(&ftrace_lock);
4837 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
4838 mutex_unlock(&ftrace_lock);
4841 mutex_unlock(&ops->func_hash->regex_lock);
4843 free_ftrace_hash(hash);
4848 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
4849 int reset, int enable)
4851 return ftrace_set_hash(ops, NULL, 0, ip, remove, reset, enable);
4855 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
4856 * @ops - the ops to set the filter with
4857 * @ip - the address to add to or remove from the filter.
4858 * @remove - non zero to remove the ip from the filter
4859 * @reset - non zero to reset all filters before applying this filter.
4861 * Filters denote which functions should be enabled when tracing is enabled
4862 * If @ip is NULL, it failes to update filter.
4864 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
4865 int remove, int reset)
4867 ftrace_ops_init(ops);
4868 return ftrace_set_addr(ops, ip, remove, reset, 1);
4870 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
4873 * ftrace_ops_set_global_filter - setup ops to use global filters
4874 * @ops - the ops which will use the global filters
4876 * ftrace users who need global function trace filtering should call this.
4877 * It can set the global filter only if ops were not initialized before.
4879 void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
4881 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
4884 ftrace_ops_init(ops);
4885 ops->func_hash = &global_ops.local_hash;
4887 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
4890 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4891 int reset, int enable)
4893 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
4897 * ftrace_set_filter - set a function to filter on in ftrace
4898 * @ops - the ops to set the filter with
4899 * @buf - the string that holds the function filter text.
4900 * @len - the length of the string.
4901 * @reset - non zero to reset all filters before applying this filter.
4903 * Filters denote which functions should be enabled when tracing is enabled.
4904 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4906 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
4909 ftrace_ops_init(ops);
4910 return ftrace_set_regex(ops, buf, len, reset, 1);
4912 EXPORT_SYMBOL_GPL(ftrace_set_filter);
4915 * ftrace_set_notrace - set a function to not trace in ftrace
4916 * @ops - the ops to set the notrace filter with
4917 * @buf - the string that holds the function notrace text.
4918 * @len - the length of the string.
4919 * @reset - non zero to reset all filters before applying this filter.
4921 * Notrace Filters denote which functions should not be enabled when tracing
4922 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4925 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
4928 ftrace_ops_init(ops);
4929 return ftrace_set_regex(ops, buf, len, reset, 0);
4931 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
4933 * ftrace_set_global_filter - set a function to filter on with global tracers
4934 * @buf - the string that holds the function filter text.
4935 * @len - the length of the string.
4936 * @reset - non zero to reset all filters before applying this filter.
4938 * Filters denote which functions should be enabled when tracing is enabled.
4939 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4941 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
4943 ftrace_set_regex(&global_ops, buf, len, reset, 1);
4945 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
4948 * ftrace_set_global_notrace - set a function to not trace with global tracers
4949 * @buf - the string that holds the function notrace text.
4950 * @len - the length of the string.
4951 * @reset - non zero to reset all filters before applying this filter.
4953 * Notrace Filters denote which functions should not be enabled when tracing
4954 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4957 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
4959 ftrace_set_regex(&global_ops, buf, len, reset, 0);
4961 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
4964 * command line interface to allow users to set filters on boot up.
4966 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
4967 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4968 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
4970 /* Used by function selftest to not test if filter is set */
4971 bool ftrace_filter_param __initdata;
4973 static int __init set_ftrace_notrace(char *str)
4975 ftrace_filter_param = true;
4976 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
4979 __setup("ftrace_notrace=", set_ftrace_notrace);
4981 static int __init set_ftrace_filter(char *str)
4983 ftrace_filter_param = true;
4984 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
4987 __setup("ftrace_filter=", set_ftrace_filter);
4989 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4990 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
4991 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4992 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
4994 static int __init set_graph_function(char *str)
4996 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
4999 __setup("ftrace_graph_filter=", set_graph_function);
5001 static int __init set_graph_notrace_function(char *str)
5003 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
5006 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
5008 static int __init set_graph_max_depth_function(char *str)
5012 fgraph_max_depth = simple_strtoul(str, NULL, 0);
5015 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
5017 static void __init set_ftrace_early_graph(char *buf, int enable)
5021 struct ftrace_hash *hash;
5023 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5028 func = strsep(&buf, ",");
5029 /* we allow only one expression at a time */
5030 ret = ftrace_graph_set_hash(hash, func);
5032 printk(KERN_DEBUG "ftrace: function %s not "
5033 "traceable\n", func);
5037 ftrace_graph_hash = hash;
5039 ftrace_graph_notrace_hash = hash;
5041 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5044 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
5048 ftrace_ops_init(ops);
5051 func = strsep(&buf, ",");
5052 ftrace_set_regex(ops, func, strlen(func), 0, enable);
5056 static void __init set_ftrace_early_filters(void)
5058 if (ftrace_filter_buf[0])
5059 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
5060 if (ftrace_notrace_buf[0])
5061 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
5062 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5063 if (ftrace_graph_buf[0])
5064 set_ftrace_early_graph(ftrace_graph_buf, 1);
5065 if (ftrace_graph_notrace_buf[0])
5066 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
5067 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5070 int ftrace_regex_release(struct inode *inode, struct file *file)
5072 struct seq_file *m = (struct seq_file *)file->private_data;
5073 struct ftrace_iterator *iter;
5074 struct ftrace_hash **orig_hash;
5075 struct trace_parser *parser;
5079 if (file->f_mode & FMODE_READ) {
5081 seq_release(inode, file);
5083 iter = file->private_data;
5085 parser = &iter->parser;
5086 if (trace_parser_loaded(parser)) {
5087 int enable = !(iter->flags & FTRACE_ITER_NOTRACE);
5089 ftrace_process_regex(iter, parser->buffer,
5090 parser->idx, enable);
5093 trace_parser_put(parser);
5095 mutex_lock(&iter->ops->func_hash->regex_lock);
5097 if (file->f_mode & FMODE_WRITE) {
5098 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5101 orig_hash = &iter->ops->func_hash->filter_hash;
5103 if (list_empty(&iter->tr->mod_trace))
5104 iter->hash->flags &= ~FTRACE_HASH_FL_MOD;
5106 iter->hash->flags |= FTRACE_HASH_FL_MOD;
5109 orig_hash = &iter->ops->func_hash->notrace_hash;
5111 mutex_lock(&ftrace_lock);
5112 ret = ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5113 iter->hash, filter_hash);
5114 mutex_unlock(&ftrace_lock);
5116 /* For read only, the hash is the ops hash */
5120 mutex_unlock(&iter->ops->func_hash->regex_lock);
5121 free_ftrace_hash(iter->hash);
5123 trace_array_put(iter->tr);
5129 static const struct file_operations ftrace_avail_fops = {
5130 .open = ftrace_avail_open,
5132 .llseek = seq_lseek,
5133 .release = seq_release_private,
5136 static const struct file_operations ftrace_enabled_fops = {
5137 .open = ftrace_enabled_open,
5139 .llseek = seq_lseek,
5140 .release = seq_release_private,
5143 static const struct file_operations ftrace_filter_fops = {
5144 .open = ftrace_filter_open,
5146 .write = ftrace_filter_write,
5147 .llseek = tracing_lseek,
5148 .release = ftrace_regex_release,
5151 static const struct file_operations ftrace_notrace_fops = {
5152 .open = ftrace_notrace_open,
5154 .write = ftrace_notrace_write,
5155 .llseek = tracing_lseek,
5156 .release = ftrace_regex_release,
5159 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5161 static DEFINE_MUTEX(graph_lock);
5163 struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
5164 struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
5166 enum graph_filter_type {
5167 GRAPH_FILTER_NOTRACE = 0,
5168 GRAPH_FILTER_FUNCTION,
5171 #define FTRACE_GRAPH_EMPTY ((void *)1)
5173 struct ftrace_graph_data {
5174 struct ftrace_hash *hash;
5175 struct ftrace_func_entry *entry;
5176 int idx; /* for hash table iteration */
5177 enum graph_filter_type type;
5178 struct ftrace_hash *new_hash;
5179 const struct seq_operations *seq_ops;
5180 struct trace_parser parser;
5184 __g_next(struct seq_file *m, loff_t *pos)
5186 struct ftrace_graph_data *fgd = m->private;
5187 struct ftrace_func_entry *entry = fgd->entry;
5188 struct hlist_head *head;
5189 int i, idx = fgd->idx;
5191 if (*pos >= fgd->hash->count)
5195 hlist_for_each_entry_continue(entry, hlist) {
5203 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
5204 head = &fgd->hash->buckets[i];
5205 hlist_for_each_entry(entry, head, hlist) {
5215 g_next(struct seq_file *m, void *v, loff_t *pos)
5218 return __g_next(m, pos);
5221 static void *g_start(struct seq_file *m, loff_t *pos)
5223 struct ftrace_graph_data *fgd = m->private;
5225 mutex_lock(&graph_lock);
5227 if (fgd->type == GRAPH_FILTER_FUNCTION)
5228 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5229 lockdep_is_held(&graph_lock));
5231 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5232 lockdep_is_held(&graph_lock));
5234 /* Nothing, tell g_show to print all functions are enabled */
5235 if (ftrace_hash_empty(fgd->hash) && !*pos)
5236 return FTRACE_GRAPH_EMPTY;
5240 return __g_next(m, pos);
5243 static void g_stop(struct seq_file *m, void *p)
5245 mutex_unlock(&graph_lock);
5248 static int g_show(struct seq_file *m, void *v)
5250 struct ftrace_func_entry *entry = v;
5255 if (entry == FTRACE_GRAPH_EMPTY) {
5256 struct ftrace_graph_data *fgd = m->private;
5258 if (fgd->type == GRAPH_FILTER_FUNCTION)
5259 seq_puts(m, "#### all functions enabled ####\n");
5261 seq_puts(m, "#### no functions disabled ####\n");
5265 seq_printf(m, "%ps\n", (void *)entry->ip);
5270 static const struct seq_operations ftrace_graph_seq_ops = {
5278 __ftrace_graph_open(struct inode *inode, struct file *file,
5279 struct ftrace_graph_data *fgd)
5282 struct ftrace_hash *new_hash = NULL;
5284 ret = security_locked_down(LOCKDOWN_TRACEFS);
5288 if (file->f_mode & FMODE_WRITE) {
5289 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
5291 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
5294 if (file->f_flags & O_TRUNC)
5295 new_hash = alloc_ftrace_hash(size_bits);
5297 new_hash = alloc_and_copy_ftrace_hash(size_bits,
5305 if (file->f_mode & FMODE_READ) {
5306 ret = seq_open(file, &ftrace_graph_seq_ops);
5308 struct seq_file *m = file->private_data;
5312 free_ftrace_hash(new_hash);
5316 file->private_data = fgd;
5319 if (ret < 0 && file->f_mode & FMODE_WRITE)
5320 trace_parser_put(&fgd->parser);
5322 fgd->new_hash = new_hash;
5325 * All uses of fgd->hash must be taken with the graph_lock
5326 * held. The graph_lock is going to be released, so force
5327 * fgd->hash to be reinitialized when it is taken again.
5335 ftrace_graph_open(struct inode *inode, struct file *file)
5337 struct ftrace_graph_data *fgd;
5340 if (unlikely(ftrace_disabled))
5343 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5347 mutex_lock(&graph_lock);
5349 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5350 lockdep_is_held(&graph_lock));
5351 fgd->type = GRAPH_FILTER_FUNCTION;
5352 fgd->seq_ops = &ftrace_graph_seq_ops;
5354 ret = __ftrace_graph_open(inode, file, fgd);
5358 mutex_unlock(&graph_lock);
5363 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
5365 struct ftrace_graph_data *fgd;
5368 if (unlikely(ftrace_disabled))
5371 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5375 mutex_lock(&graph_lock);
5377 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5378 lockdep_is_held(&graph_lock));
5379 fgd->type = GRAPH_FILTER_NOTRACE;
5380 fgd->seq_ops = &ftrace_graph_seq_ops;
5382 ret = __ftrace_graph_open(inode, file, fgd);
5386 mutex_unlock(&graph_lock);
5391 ftrace_graph_release(struct inode *inode, struct file *file)
5393 struct ftrace_graph_data *fgd;
5394 struct ftrace_hash *old_hash, *new_hash;
5395 struct trace_parser *parser;
5398 if (file->f_mode & FMODE_READ) {
5399 struct seq_file *m = file->private_data;
5402 seq_release(inode, file);
5404 fgd = file->private_data;
5408 if (file->f_mode & FMODE_WRITE) {
5410 parser = &fgd->parser;
5412 if (trace_parser_loaded((parser))) {
5413 ret = ftrace_graph_set_hash(fgd->new_hash,
5417 trace_parser_put(parser);
5419 new_hash = __ftrace_hash_move(fgd->new_hash);
5425 mutex_lock(&graph_lock);
5427 if (fgd->type == GRAPH_FILTER_FUNCTION) {
5428 old_hash = rcu_dereference_protected(ftrace_graph_hash,
5429 lockdep_is_held(&graph_lock));
5430 rcu_assign_pointer(ftrace_graph_hash, new_hash);
5432 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5433 lockdep_is_held(&graph_lock));
5434 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
5437 mutex_unlock(&graph_lock);
5440 * We need to do a hard force of sched synchronization.
5441 * This is because we use preempt_disable() to do RCU, but
5442 * the function tracers can be called where RCU is not watching
5443 * (like before user_exit()). We can not rely on the RCU
5444 * infrastructure to do the synchronization, thus we must do it
5447 schedule_on_each_cpu(ftrace_sync);
5449 free_ftrace_hash(old_hash);
5453 free_ftrace_hash(fgd->new_hash);
5460 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
5462 struct ftrace_glob func_g;
5463 struct dyn_ftrace *rec;
5464 struct ftrace_page *pg;
5465 struct ftrace_func_entry *entry;
5470 func_g.type = filter_parse_regex(buffer, strlen(buffer),
5471 &func_g.search, ¬);
5473 func_g.len = strlen(func_g.search);
5475 mutex_lock(&ftrace_lock);
5477 if (unlikely(ftrace_disabled)) {
5478 mutex_unlock(&ftrace_lock);
5482 do_for_each_ftrace_rec(pg, rec) {
5484 if (rec->flags & FTRACE_FL_DISABLED)
5487 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
5488 entry = ftrace_lookup_ip(hash, rec->ip);
5495 if (add_hash_entry(hash, rec->ip) < 0)
5499 free_hash_entry(hash, entry);
5504 } while_for_each_ftrace_rec();
5506 mutex_unlock(&ftrace_lock);
5515 ftrace_graph_write(struct file *file, const char __user *ubuf,
5516 size_t cnt, loff_t *ppos)
5518 ssize_t read, ret = 0;
5519 struct ftrace_graph_data *fgd = file->private_data;
5520 struct trace_parser *parser;
5525 /* Read mode uses seq functions */
5526 if (file->f_mode & FMODE_READ) {
5527 struct seq_file *m = file->private_data;
5531 parser = &fgd->parser;
5533 read = trace_get_user(parser, ubuf, cnt, ppos);
5535 if (read >= 0 && trace_parser_loaded(parser) &&
5536 !trace_parser_cont(parser)) {
5538 ret = ftrace_graph_set_hash(fgd->new_hash,
5540 trace_parser_clear(parser);
5549 static const struct file_operations ftrace_graph_fops = {
5550 .open = ftrace_graph_open,
5552 .write = ftrace_graph_write,
5553 .llseek = tracing_lseek,
5554 .release = ftrace_graph_release,
5557 static const struct file_operations ftrace_graph_notrace_fops = {
5558 .open = ftrace_graph_notrace_open,
5560 .write = ftrace_graph_write,
5561 .llseek = tracing_lseek,
5562 .release = ftrace_graph_release,
5564 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5566 void ftrace_create_filter_files(struct ftrace_ops *ops,
5567 struct dentry *parent)
5570 trace_create_file("set_ftrace_filter", 0644, parent,
5571 ops, &ftrace_filter_fops);
5573 trace_create_file("set_ftrace_notrace", 0644, parent,
5574 ops, &ftrace_notrace_fops);
5578 * The name "destroy_filter_files" is really a misnomer. Although
5579 * in the future, it may actually delete the files, but this is
5580 * really intended to make sure the ops passed in are disabled
5581 * and that when this function returns, the caller is free to
5584 * The "destroy" name is only to match the "create" name that this
5585 * should be paired with.
5587 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
5589 mutex_lock(&ftrace_lock);
5590 if (ops->flags & FTRACE_OPS_FL_ENABLED)
5591 ftrace_shutdown(ops, 0);
5592 ops->flags |= FTRACE_OPS_FL_DELETED;
5593 ftrace_free_filter(ops);
5594 mutex_unlock(&ftrace_lock);
5597 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
5600 trace_create_file("available_filter_functions", 0444,
5601 d_tracer, NULL, &ftrace_avail_fops);
5603 trace_create_file("enabled_functions", 0444,
5604 d_tracer, NULL, &ftrace_enabled_fops);
5606 ftrace_create_filter_files(&global_ops, d_tracer);
5608 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5609 trace_create_file("set_graph_function", 0644, d_tracer,
5611 &ftrace_graph_fops);
5612 trace_create_file("set_graph_notrace", 0644, d_tracer,
5614 &ftrace_graph_notrace_fops);
5615 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5620 static int ftrace_cmp_ips(const void *a, const void *b)
5622 const unsigned long *ipa = a;
5623 const unsigned long *ipb = b;
5632 static int ftrace_process_locs(struct module *mod,
5633 unsigned long *start,
5636 struct ftrace_page *pg_unuse = NULL;
5637 struct ftrace_page *start_pg;
5638 struct ftrace_page *pg;
5639 struct dyn_ftrace *rec;
5640 unsigned long skipped = 0;
5641 unsigned long count;
5644 unsigned long flags = 0; /* Shut up gcc */
5647 count = end - start;
5652 sort(start, count, sizeof(*start),
5653 ftrace_cmp_ips, NULL);
5655 start_pg = ftrace_allocate_pages(count);
5659 mutex_lock(&ftrace_lock);
5662 * Core and each module needs their own pages, as
5663 * modules will free them when they are removed.
5664 * Force a new page to be allocated for modules.
5667 WARN_ON(ftrace_pages || ftrace_pages_start);
5668 /* First initialization */
5669 ftrace_pages = ftrace_pages_start = start_pg;
5674 if (WARN_ON(ftrace_pages->next)) {
5675 /* Hmm, we have free pages? */
5676 while (ftrace_pages->next)
5677 ftrace_pages = ftrace_pages->next;
5680 ftrace_pages->next = start_pg;
5686 unsigned long end_offset;
5687 addr = ftrace_call_adjust(*p++);
5689 * Some architecture linkers will pad between
5690 * the different mcount_loc sections of different
5691 * object files to satisfy alignments.
5692 * Skip any NULL pointers.
5699 end_offset = (pg->index+1) * sizeof(pg->records[0]);
5700 if (end_offset > PAGE_SIZE << pg->order) {
5701 /* We should have allocated enough */
5702 if (WARN_ON(!pg->next))
5707 rec = &pg->records[pg->index++];
5712 pg_unuse = pg->next;
5716 /* Assign the last page to ftrace_pages */
5720 * We only need to disable interrupts on start up
5721 * because we are modifying code that an interrupt
5722 * may execute, and the modification is not atomic.
5723 * But for modules, nothing runs the code we modify
5724 * until we are finished with it, and there's no
5725 * reason to cause large interrupt latencies while we do it.
5728 local_irq_save(flags);
5729 ftrace_update_code(mod, start_pg);
5731 local_irq_restore(flags);
5734 mutex_unlock(&ftrace_lock);
5736 /* We should have used all pages unless we skipped some */
5739 ftrace_free_pages(pg_unuse);
5744 struct ftrace_mod_func {
5745 struct list_head list;
5751 struct ftrace_mod_map {
5752 struct rcu_head rcu;
5753 struct list_head list;
5755 unsigned long start_addr;
5756 unsigned long end_addr;
5757 struct list_head funcs;
5758 unsigned int num_funcs;
5761 #ifdef CONFIG_MODULES
5763 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
5765 static LIST_HEAD(ftrace_mod_maps);
5767 static int referenced_filters(struct dyn_ftrace *rec)
5769 struct ftrace_ops *ops;
5772 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
5773 if (ops_references_rec(ops, rec)) {
5775 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
5776 rec->flags |= FTRACE_FL_REGS;
5784 clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
5786 struct ftrace_func_entry *entry;
5787 struct dyn_ftrace *rec;
5790 if (ftrace_hash_empty(hash))
5793 for (i = 0; i < pg->index; i++) {
5794 rec = &pg->records[i];
5795 entry = __ftrace_lookup_ip(hash, rec->ip);
5797 * Do not allow this rec to match again.
5798 * Yeah, it may waste some memory, but will be removed
5799 * if/when the hash is modified again.
5806 /* Clear any records from hashs */
5807 static void clear_mod_from_hashes(struct ftrace_page *pg)
5809 struct trace_array *tr;
5811 mutex_lock(&trace_types_lock);
5812 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
5813 if (!tr->ops || !tr->ops->func_hash)
5815 mutex_lock(&tr->ops->func_hash->regex_lock);
5816 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
5817 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
5818 mutex_unlock(&tr->ops->func_hash->regex_lock);
5820 mutex_unlock(&trace_types_lock);
5823 static void ftrace_free_mod_map(struct rcu_head *rcu)
5825 struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
5826 struct ftrace_mod_func *mod_func;
5827 struct ftrace_mod_func *n;
5829 /* All the contents of mod_map are now not visible to readers */
5830 list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
5831 kfree(mod_func->name);
5832 list_del(&mod_func->list);
5839 void ftrace_release_mod(struct module *mod)
5841 struct ftrace_mod_map *mod_map;
5842 struct ftrace_mod_map *n;
5843 struct dyn_ftrace *rec;
5844 struct ftrace_page **last_pg;
5845 struct ftrace_page *tmp_page = NULL;
5846 struct ftrace_page *pg;
5848 mutex_lock(&ftrace_lock);
5850 if (ftrace_disabled)
5853 list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
5854 if (mod_map->mod == mod) {
5855 list_del_rcu(&mod_map->list);
5856 call_rcu(&mod_map->rcu, ftrace_free_mod_map);
5862 * Each module has its own ftrace_pages, remove
5863 * them from the list.
5865 last_pg = &ftrace_pages_start;
5866 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
5867 rec = &pg->records[0];
5868 if (within_module_core(rec->ip, mod) ||
5869 within_module_init(rec->ip, mod)) {
5871 * As core pages are first, the first
5872 * page should never be a module page.
5874 if (WARN_ON(pg == ftrace_pages_start))
5877 /* Check if we are deleting the last page */
5878 if (pg == ftrace_pages)
5879 ftrace_pages = next_to_ftrace_page(last_pg);
5881 ftrace_update_tot_cnt -= pg->index;
5882 *last_pg = pg->next;
5884 pg->next = tmp_page;
5887 last_pg = &pg->next;
5890 mutex_unlock(&ftrace_lock);
5892 for (pg = tmp_page; pg; pg = tmp_page) {
5894 /* Needs to be called outside of ftrace_lock */
5895 clear_mod_from_hashes(pg);
5898 free_pages((unsigned long)pg->records, pg->order);
5899 ftrace_number_of_pages -= 1 << pg->order;
5901 tmp_page = pg->next;
5903 ftrace_number_of_groups--;
5907 void ftrace_module_enable(struct module *mod)
5909 struct dyn_ftrace *rec;
5910 struct ftrace_page *pg;
5912 mutex_lock(&ftrace_lock);
5914 if (ftrace_disabled)
5918 * If the tracing is enabled, go ahead and enable the record.
5920 * The reason not to enable the record immediately is the
5921 * inherent check of ftrace_make_nop/ftrace_make_call for
5922 * correct previous instructions. Making first the NOP
5923 * conversion puts the module to the correct state, thus
5924 * passing the ftrace_make_call check.
5926 * We also delay this to after the module code already set the
5927 * text to read-only, as we now need to set it back to read-write
5928 * so that we can modify the text.
5930 if (ftrace_start_up)
5931 ftrace_arch_code_modify_prepare();
5933 do_for_each_ftrace_rec(pg, rec) {
5936 * do_for_each_ftrace_rec() is a double loop.
5937 * module text shares the pg. If a record is
5938 * not part of this module, then skip this pg,
5939 * which the "break" will do.
5941 if (!within_module_core(rec->ip, mod) &&
5942 !within_module_init(rec->ip, mod))
5948 * When adding a module, we need to check if tracers are
5949 * currently enabled and if they are, and can trace this record,
5950 * we need to enable the module functions as well as update the
5951 * reference counts for those function records.
5953 if (ftrace_start_up)
5954 cnt += referenced_filters(rec);
5956 rec->flags &= ~FTRACE_FL_DISABLED;
5959 if (ftrace_start_up && cnt) {
5960 int failed = __ftrace_replace_code(rec, 1);
5962 ftrace_bug(failed, rec);
5967 } while_for_each_ftrace_rec();
5970 if (ftrace_start_up)
5971 ftrace_arch_code_modify_post_process();
5974 mutex_unlock(&ftrace_lock);
5976 process_cached_mods(mod->name);
5979 void ftrace_module_init(struct module *mod)
5981 if (ftrace_disabled || !mod->num_ftrace_callsites)
5984 ftrace_process_locs(mod, mod->ftrace_callsites,
5985 mod->ftrace_callsites + mod->num_ftrace_callsites);
5988 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
5989 struct dyn_ftrace *rec)
5991 struct ftrace_mod_func *mod_func;
5992 unsigned long symsize;
5993 unsigned long offset;
5994 char str[KSYM_SYMBOL_LEN];
5998 ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
6002 mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
6006 mod_func->name = kstrdup(str, GFP_KERNEL);
6007 if (!mod_func->name) {
6012 mod_func->ip = rec->ip - offset;
6013 mod_func->size = symsize;
6015 mod_map->num_funcs++;
6017 list_add_rcu(&mod_func->list, &mod_map->funcs);
6020 static struct ftrace_mod_map *
6021 allocate_ftrace_mod_map(struct module *mod,
6022 unsigned long start, unsigned long end)
6024 struct ftrace_mod_map *mod_map;
6026 mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
6031 mod_map->start_addr = start;
6032 mod_map->end_addr = end;
6033 mod_map->num_funcs = 0;
6035 INIT_LIST_HEAD_RCU(&mod_map->funcs);
6037 list_add_rcu(&mod_map->list, &ftrace_mod_maps);
6043 ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
6044 unsigned long addr, unsigned long *size,
6045 unsigned long *off, char *sym)
6047 struct ftrace_mod_func *found_func = NULL;
6048 struct ftrace_mod_func *mod_func;
6050 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6051 if (addr >= mod_func->ip &&
6052 addr < mod_func->ip + mod_func->size) {
6053 found_func = mod_func;
6060 *size = found_func->size;
6062 *off = addr - found_func->ip;
6064 strlcpy(sym, found_func->name, KSYM_NAME_LEN);
6066 return found_func->name;
6073 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
6074 unsigned long *off, char **modname, char *sym)
6076 struct ftrace_mod_map *mod_map;
6077 const char *ret = NULL;
6079 /* mod_map is freed via call_rcu() */
6081 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6082 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
6085 *modname = mod_map->mod->name;
6094 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
6095 char *type, char *name,
6096 char *module_name, int *exported)
6098 struct ftrace_mod_map *mod_map;
6099 struct ftrace_mod_func *mod_func;
6102 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6104 if (symnum >= mod_map->num_funcs) {
6105 symnum -= mod_map->num_funcs;
6109 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6115 *value = mod_func->ip;
6117 strlcpy(name, mod_func->name, KSYM_NAME_LEN);
6118 strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
6131 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6132 struct dyn_ftrace *rec) { }
6133 static inline struct ftrace_mod_map *
6134 allocate_ftrace_mod_map(struct module *mod,
6135 unsigned long start, unsigned long end)
6139 #endif /* CONFIG_MODULES */
6141 struct ftrace_init_func {
6142 struct list_head list;
6146 /* Clear any init ips from hashes */
6148 clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
6150 struct ftrace_func_entry *entry;
6152 entry = ftrace_lookup_ip(hash, func->ip);
6154 * Do not allow this rec to match again.
6155 * Yeah, it may waste some memory, but will be removed
6156 * if/when the hash is modified again.
6163 clear_func_from_hashes(struct ftrace_init_func *func)
6165 struct trace_array *tr;
6167 mutex_lock(&trace_types_lock);
6168 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6169 if (!tr->ops || !tr->ops->func_hash)
6171 mutex_lock(&tr->ops->func_hash->regex_lock);
6172 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
6173 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
6174 mutex_unlock(&tr->ops->func_hash->regex_lock);
6176 mutex_unlock(&trace_types_lock);
6179 static void add_to_clear_hash_list(struct list_head *clear_list,
6180 struct dyn_ftrace *rec)
6182 struct ftrace_init_func *func;
6184 func = kmalloc(sizeof(*func), GFP_KERNEL);
6186 WARN_ONCE(1, "alloc failure, ftrace filter could be stale\n");
6191 list_add(&func->list, clear_list);
6194 void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
6196 unsigned long start = (unsigned long)(start_ptr);
6197 unsigned long end = (unsigned long)(end_ptr);
6198 struct ftrace_page **last_pg = &ftrace_pages_start;
6199 struct ftrace_page *pg;
6200 struct dyn_ftrace *rec;
6201 struct dyn_ftrace key;
6202 struct ftrace_mod_map *mod_map = NULL;
6203 struct ftrace_init_func *func, *func_next;
6204 struct list_head clear_hash;
6206 INIT_LIST_HEAD(&clear_hash);
6209 key.flags = end; /* overload flags, as it is unsigned long */
6211 mutex_lock(&ftrace_lock);
6214 * If we are freeing module init memory, then check if
6215 * any tracer is active. If so, we need to save a mapping of
6216 * the module functions being freed with the address.
6218 if (mod && ftrace_ops_list != &ftrace_list_end)
6219 mod_map = allocate_ftrace_mod_map(mod, start, end);
6221 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
6222 if (end < pg->records[0].ip ||
6223 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
6226 rec = bsearch(&key, pg->records, pg->index,
6227 sizeof(struct dyn_ftrace),
6232 /* rec will be cleared from hashes after ftrace_lock unlock */
6233 add_to_clear_hash_list(&clear_hash, rec);
6236 save_ftrace_mod_rec(mod_map, rec);
6239 ftrace_update_tot_cnt--;
6241 *last_pg = pg->next;
6243 free_pages((unsigned long)pg->records, pg->order);
6244 ftrace_number_of_pages -= 1 << pg->order;
6246 ftrace_number_of_groups--;
6248 pg = container_of(last_pg, struct ftrace_page, next);
6253 memmove(rec, rec + 1,
6254 (pg->index - (rec - pg->records)) * sizeof(*rec));
6255 /* More than one function may be in this block */
6258 mutex_unlock(&ftrace_lock);
6260 list_for_each_entry_safe(func, func_next, &clear_hash, list) {
6261 clear_func_from_hashes(func);
6266 void __init ftrace_free_init_mem(void)
6268 void *start = (void *)(&__init_begin);
6269 void *end = (void *)(&__init_end);
6271 ftrace_free_mem(NULL, start, end);
6274 void __init ftrace_init(void)
6276 extern unsigned long __start_mcount_loc[];
6277 extern unsigned long __stop_mcount_loc[];
6278 unsigned long count, flags;
6281 local_irq_save(flags);
6282 ret = ftrace_dyn_arch_init();
6283 local_irq_restore(flags);
6287 count = __stop_mcount_loc - __start_mcount_loc;
6289 pr_info("ftrace: No functions to be traced?\n");
6293 pr_info("ftrace: allocating %ld entries in %ld pages\n",
6294 count, DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
6296 last_ftrace_enabled = ftrace_enabled = 1;
6298 ret = ftrace_process_locs(NULL,
6302 pr_info("ftrace: allocated %ld pages with %ld groups\n",
6303 ftrace_number_of_pages, ftrace_number_of_groups);
6305 set_ftrace_early_filters();
6309 ftrace_disabled = 1;
6312 /* Do nothing if arch does not support this */
6313 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
6317 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6319 arch_ftrace_update_trampoline(ops);
6322 void ftrace_init_trace_array(struct trace_array *tr)
6324 INIT_LIST_HEAD(&tr->func_probes);
6325 INIT_LIST_HEAD(&tr->mod_trace);
6326 INIT_LIST_HEAD(&tr->mod_notrace);
6330 struct ftrace_ops global_ops = {
6331 .func = ftrace_stub,
6332 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
6333 FTRACE_OPS_FL_INITIALIZED |
6337 static int __init ftrace_nodyn_init(void)
6342 core_initcall(ftrace_nodyn_init);
6344 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
6345 static inline void ftrace_startup_enable(int command) { }
6346 static inline void ftrace_startup_all(int command) { }
6348 # define ftrace_startup_sysctl() do { } while (0)
6349 # define ftrace_shutdown_sysctl() do { } while (0)
6351 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6355 #endif /* CONFIG_DYNAMIC_FTRACE */
6357 __init void ftrace_init_global_array_ops(struct trace_array *tr)
6359 tr->ops = &global_ops;
6360 tr->ops->private = tr;
6361 ftrace_init_trace_array(tr);
6364 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
6366 /* If we filter on pids, update to use the pid function */
6367 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
6368 if (WARN_ON(tr->ops->func != ftrace_stub))
6369 printk("ftrace ops had %pS for function\n",
6372 tr->ops->func = func;
6373 tr->ops->private = tr;
6376 void ftrace_reset_array_ops(struct trace_array *tr)
6378 tr->ops->func = ftrace_stub;
6381 static nokprobe_inline void
6382 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6383 struct ftrace_ops *ignored, struct pt_regs *regs)
6385 struct ftrace_ops *op;
6388 bit = trace_test_and_set_recursion(TRACE_LIST_START);
6393 * Some of the ops may be dynamically allocated,
6394 * they must be freed after a synchronize_rcu().
6396 preempt_disable_notrace();
6398 do_for_each_ftrace_op(op, ftrace_ops_list) {
6399 /* Stub functions don't need to be called nor tested */
6400 if (op->flags & FTRACE_OPS_FL_STUB)
6403 * Check the following for each ops before calling their func:
6404 * if RCU flag is set, then rcu_is_watching() must be true
6405 * if PER_CPU is set, then ftrace_function_local_disable()
6407 * Otherwise test if the ip matches the ops filter
6409 * If any of the above fails then the op->func() is not executed.
6411 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
6412 ftrace_ops_test(op, ip, regs)) {
6413 if (FTRACE_WARN_ON(!op->func)) {
6414 pr_warn("op=%p %pS\n", op, op);
6417 op->func(ip, parent_ip, op, regs);
6419 } while_for_each_ftrace_op(op);
6421 preempt_enable_notrace();
6422 trace_clear_recursion(bit);
6426 * Some archs only support passing ip and parent_ip. Even though
6427 * the list function ignores the op parameter, we do not want any
6428 * C side effects, where a function is called without the caller
6429 * sending a third parameter.
6430 * Archs are to support both the regs and ftrace_ops at the same time.
6431 * If they support ftrace_ops, it is assumed they support regs.
6432 * If call backs want to use regs, they must either check for regs
6433 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
6434 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
6435 * An architecture can pass partial regs with ftrace_ops and still
6436 * set the ARCH_SUPPORTS_FTRACE_OPS.
6438 #if ARCH_SUPPORTS_FTRACE_OPS
6439 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6440 struct ftrace_ops *op, struct pt_regs *regs)
6442 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
6444 NOKPROBE_SYMBOL(ftrace_ops_list_func);
6446 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
6448 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
6450 NOKPROBE_SYMBOL(ftrace_ops_no_ops);
6454 * If there's only one function registered but it does not support
6455 * recursion, needs RCU protection and/or requires per cpu handling, then
6456 * this function will be called by the mcount trampoline.
6458 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
6459 struct ftrace_ops *op, struct pt_regs *regs)
6463 bit = trace_test_and_set_recursion(TRACE_LIST_START);
6467 preempt_disable_notrace();
6469 if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
6470 op->func(ip, parent_ip, op, regs);
6472 preempt_enable_notrace();
6473 trace_clear_recursion(bit);
6475 NOKPROBE_SYMBOL(ftrace_ops_assist_func);
6478 * ftrace_ops_get_func - get the function a trampoline should call
6479 * @ops: the ops to get the function for
6481 * Normally the mcount trampoline will call the ops->func, but there
6482 * are times that it should not. For example, if the ops does not
6483 * have its own recursion protection, then it should call the
6484 * ftrace_ops_assist_func() instead.
6486 * Returns the function that the trampoline should call for @ops.
6488 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
6491 * If the function does not handle recursion, needs to be RCU safe,
6492 * or does per cpu logic, then we need to call the assist handler.
6494 if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
6495 ops->flags & FTRACE_OPS_FL_RCU)
6496 return ftrace_ops_assist_func;
6502 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
6503 struct task_struct *prev, struct task_struct *next)
6505 struct trace_array *tr = data;
6506 struct trace_pid_list *pid_list;
6508 pid_list = rcu_dereference_sched(tr->function_pids);
6510 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
6511 trace_ignore_this_task(pid_list, next));
6515 ftrace_pid_follow_sched_process_fork(void *data,
6516 struct task_struct *self,
6517 struct task_struct *task)
6519 struct trace_pid_list *pid_list;
6520 struct trace_array *tr = data;
6522 pid_list = rcu_dereference_sched(tr->function_pids);
6523 trace_filter_add_remove_task(pid_list, self, task);
6527 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
6529 struct trace_pid_list *pid_list;
6530 struct trace_array *tr = data;
6532 pid_list = rcu_dereference_sched(tr->function_pids);
6533 trace_filter_add_remove_task(pid_list, NULL, task);
6536 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
6539 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6541 register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
6544 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6546 unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
6551 static void clear_ftrace_pids(struct trace_array *tr)
6553 struct trace_pid_list *pid_list;
6556 pid_list = rcu_dereference_protected(tr->function_pids,
6557 lockdep_is_held(&ftrace_lock));
6561 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
6563 for_each_possible_cpu(cpu)
6564 per_cpu_ptr(tr->trace_buffer.data, cpu)->ftrace_ignore_pid = false;
6566 rcu_assign_pointer(tr->function_pids, NULL);
6568 /* Wait till all users are no longer using pid filtering */
6571 trace_free_pid_list(pid_list);
6574 void ftrace_clear_pids(struct trace_array *tr)
6576 mutex_lock(&ftrace_lock);
6578 clear_ftrace_pids(tr);
6580 mutex_unlock(&ftrace_lock);
6583 static void ftrace_pid_reset(struct trace_array *tr)
6585 mutex_lock(&ftrace_lock);
6586 clear_ftrace_pids(tr);
6588 ftrace_update_pid_func();
6589 ftrace_startup_all(0);
6591 mutex_unlock(&ftrace_lock);
6594 /* Greater than any max PID */
6595 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
6597 static void *fpid_start(struct seq_file *m, loff_t *pos)
6600 struct trace_pid_list *pid_list;
6601 struct trace_array *tr = m->private;
6603 mutex_lock(&ftrace_lock);
6604 rcu_read_lock_sched();
6606 pid_list = rcu_dereference_sched(tr->function_pids);
6609 return !(*pos) ? FTRACE_NO_PIDS : NULL;
6611 return trace_pid_start(pid_list, pos);
6614 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
6616 struct trace_array *tr = m->private;
6617 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
6619 if (v == FTRACE_NO_PIDS) {
6623 return trace_pid_next(pid_list, v, pos);
6626 static void fpid_stop(struct seq_file *m, void *p)
6629 rcu_read_unlock_sched();
6630 mutex_unlock(&ftrace_lock);
6633 static int fpid_show(struct seq_file *m, void *v)
6635 if (v == FTRACE_NO_PIDS) {
6636 seq_puts(m, "no pid\n");
6640 return trace_pid_show(m, v);
6643 static const struct seq_operations ftrace_pid_sops = {
6644 .start = fpid_start,
6651 ftrace_pid_open(struct inode *inode, struct file *file)
6653 struct trace_array *tr = inode->i_private;
6657 ret = tracing_check_open_get_tr(tr);
6661 if ((file->f_mode & FMODE_WRITE) &&
6662 (file->f_flags & O_TRUNC))
6663 ftrace_pid_reset(tr);
6665 ret = seq_open(file, &ftrace_pid_sops);
6667 trace_array_put(tr);
6669 m = file->private_data;
6670 /* copy tr over to seq ops */
6677 static void ignore_task_cpu(void *data)
6679 struct trace_array *tr = data;
6680 struct trace_pid_list *pid_list;
6683 * This function is called by on_each_cpu() while the
6684 * event_mutex is held.
6686 pid_list = rcu_dereference_protected(tr->function_pids,
6687 mutex_is_locked(&ftrace_lock));
6689 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
6690 trace_ignore_this_task(pid_list, current));
6694 ftrace_pid_write(struct file *filp, const char __user *ubuf,
6695 size_t cnt, loff_t *ppos)
6697 struct seq_file *m = filp->private_data;
6698 struct trace_array *tr = m->private;
6699 struct trace_pid_list *filtered_pids = NULL;
6700 struct trace_pid_list *pid_list;
6706 mutex_lock(&ftrace_lock);
6708 filtered_pids = rcu_dereference_protected(tr->function_pids,
6709 lockdep_is_held(&ftrace_lock));
6711 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
6715 rcu_assign_pointer(tr->function_pids, pid_list);
6717 if (filtered_pids) {
6719 trace_free_pid_list(filtered_pids);
6720 } else if (pid_list) {
6721 /* Register a probe to set whether to ignore the tracing of a task */
6722 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
6726 * Ignoring of pids is done at task switch. But we have to
6727 * check for those tasks that are currently running.
6728 * Always do this in case a pid was appended or removed.
6730 on_each_cpu(ignore_task_cpu, tr, 1);
6732 ftrace_update_pid_func();
6733 ftrace_startup_all(0);
6735 mutex_unlock(&ftrace_lock);
6744 ftrace_pid_release(struct inode *inode, struct file *file)
6746 struct trace_array *tr = inode->i_private;
6748 trace_array_put(tr);
6750 return seq_release(inode, file);
6753 static const struct file_operations ftrace_pid_fops = {
6754 .open = ftrace_pid_open,
6755 .write = ftrace_pid_write,
6757 .llseek = tracing_lseek,
6758 .release = ftrace_pid_release,
6761 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
6763 trace_create_file("set_ftrace_pid", 0644, d_tracer,
6764 tr, &ftrace_pid_fops);
6767 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
6768 struct dentry *d_tracer)
6770 /* Only the top level directory has the dyn_tracefs and profile */
6771 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
6773 ftrace_init_dyn_tracefs(d_tracer);
6774 ftrace_profile_tracefs(d_tracer);
6778 * ftrace_kill - kill ftrace
6780 * This function should be used by panic code. It stops ftrace
6781 * but in a not so nice way. If you need to simply kill ftrace
6782 * from a non-atomic section, use ftrace_kill.
6784 void ftrace_kill(void)
6786 ftrace_disabled = 1;
6788 ftrace_trace_function = ftrace_stub;
6792 * Test if ftrace is dead or not.
6794 int ftrace_is_dead(void)
6796 return ftrace_disabled;
6800 * register_ftrace_function - register a function for profiling
6801 * @ops - ops structure that holds the function for profiling.
6803 * Register a function to be called by all functions in the
6806 * Note: @ops->func and all the functions it calls must be labeled
6807 * with "notrace", otherwise it will go into a
6810 int register_ftrace_function(struct ftrace_ops *ops)
6814 ftrace_ops_init(ops);
6816 mutex_lock(&ftrace_lock);
6818 ret = ftrace_startup(ops, 0);
6820 mutex_unlock(&ftrace_lock);
6824 EXPORT_SYMBOL_GPL(register_ftrace_function);
6827 * unregister_ftrace_function - unregister a function for profiling.
6828 * @ops - ops structure that holds the function to unregister
6830 * Unregister a function that was added to be called by ftrace profiling.
6832 int unregister_ftrace_function(struct ftrace_ops *ops)
6836 mutex_lock(&ftrace_lock);
6837 ret = ftrace_shutdown(ops, 0);
6838 mutex_unlock(&ftrace_lock);
6842 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
6845 ftrace_enable_sysctl(struct ctl_table *table, int write,
6846 void __user *buffer, size_t *lenp,
6851 mutex_lock(&ftrace_lock);
6853 if (unlikely(ftrace_disabled))
6856 ret = proc_dointvec(table, write, buffer, lenp, ppos);
6858 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
6861 last_ftrace_enabled = !!ftrace_enabled;
6863 if (ftrace_enabled) {
6865 /* we are starting ftrace again */
6866 if (rcu_dereference_protected(ftrace_ops_list,
6867 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
6868 update_ftrace_function();
6870 ftrace_startup_sysctl();
6873 /* stopping ftrace calls (just send to ftrace_stub) */
6874 ftrace_trace_function = ftrace_stub;
6876 ftrace_shutdown_sysctl();
6880 mutex_unlock(&ftrace_lock);