2 * Infrastructure for profiling code inserted by 'gcc -pg'.
4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
7 * Originally ported from the -rt patch by:
8 * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
10 * Based on code in the latency_tracer, that is:
12 * Copyright (C) 2004-2006 Ingo Molnar
13 * Copyright (C) 2004 Nadia Yvette Chambers
16 #include <linux/stop_machine.h>
17 #include <linux/clocksource.h>
18 #include <linux/sched/task.h>
19 #include <linux/kallsyms.h>
20 #include <linux/seq_file.h>
21 #include <linux/suspend.h>
22 #include <linux/tracefs.h>
23 #include <linux/hardirq.h>
24 #include <linux/kthread.h>
25 #include <linux/uaccess.h>
26 #include <linux/bsearch.h>
27 #include <linux/module.h>
28 #include <linux/ftrace.h>
29 #include <linux/sysctl.h>
30 #include <linux/slab.h>
31 #include <linux/ctype.h>
32 #include <linux/sort.h>
33 #include <linux/list.h>
34 #include <linux/hash.h>
35 #include <linux/rcupdate.h>
37 #include <trace/events/sched.h>
39 #include <asm/sections.h>
40 #include <asm/setup.h>
42 #include "trace_output.h"
43 #include "trace_stat.h"
45 #define FTRACE_WARN_ON(cond) \
53 #define FTRACE_WARN_ON_ONCE(cond) \
56 if (WARN_ON_ONCE(___r)) \
61 /* hash bits for specific function selection */
62 #define FTRACE_HASH_BITS 7
63 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
64 #define FTRACE_HASH_DEFAULT_BITS 10
65 #define FTRACE_HASH_MAX_BITS 12
67 #ifdef CONFIG_DYNAMIC_FTRACE
68 #define INIT_OPS_HASH(opsname) \
69 .func_hash = &opsname.local_hash, \
70 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
71 #define ASSIGN_OPS_HASH(opsname, val) \
73 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
75 #define INIT_OPS_HASH(opsname)
76 #define ASSIGN_OPS_HASH(opsname, val)
79 static struct ftrace_ops ftrace_list_end __read_mostly = {
81 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
82 INIT_OPS_HASH(ftrace_list_end)
85 /* ftrace_enabled is a method to turn ftrace on or off */
86 int ftrace_enabled __read_mostly;
87 static int last_ftrace_enabled;
89 /* Current function tracing op */
90 struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
91 /* What to set function_trace_op to */
92 static struct ftrace_ops *set_function_trace_op;
94 static bool ftrace_pids_enabled(struct ftrace_ops *ops)
96 struct trace_array *tr;
98 if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
103 return tr->function_pids != NULL;
106 static void ftrace_update_trampoline(struct ftrace_ops *ops);
109 * ftrace_disabled is set when an anomaly is discovered.
110 * ftrace_disabled is much stronger than ftrace_enabled.
112 static int ftrace_disabled __read_mostly;
114 static DEFINE_MUTEX(ftrace_lock);
116 static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
117 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
118 static struct ftrace_ops global_ops;
120 #if ARCH_SUPPORTS_FTRACE_OPS
121 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
122 struct ftrace_ops *op, struct pt_regs *regs);
124 /* See comment below, where ftrace_ops_list_func is defined */
125 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
126 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
130 * Traverse the ftrace_global_list, invoking all entries. The reason that we
131 * can use rcu_dereference_raw_notrace() is that elements removed from this list
132 * are simply leaked, so there is no need to interact with a grace-period
133 * mechanism. The rcu_dereference_raw_notrace() calls are needed to handle
134 * concurrent insertions into the ftrace_global_list.
136 * Silly Alpha and silly pointer-speculation compiler optimizations!
138 #define do_for_each_ftrace_op(op, list) \
139 op = rcu_dereference_raw_notrace(list); \
143 * Optimized for just a single item in the list (as that is the normal case).
145 #define while_for_each_ftrace_op(op) \
146 while (likely(op = rcu_dereference_raw_notrace((op)->next)) && \
147 unlikely((op) != &ftrace_list_end))
149 static inline void ftrace_ops_init(struct ftrace_ops *ops)
151 #ifdef CONFIG_DYNAMIC_FTRACE
152 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
153 mutex_init(&ops->local_hash.regex_lock);
154 ops->func_hash = &ops->local_hash;
155 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
161 * ftrace_nr_registered_ops - return number of ops registered
163 * Returns the number of ftrace_ops registered and tracing functions
165 int ftrace_nr_registered_ops(void)
167 struct ftrace_ops *ops;
170 mutex_lock(&ftrace_lock);
172 for (ops = ftrace_ops_list;
173 ops != &ftrace_list_end; ops = ops->next)
176 mutex_unlock(&ftrace_lock);
181 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
182 struct ftrace_ops *op, struct pt_regs *regs)
184 struct trace_array *tr = op->private;
186 if (tr && this_cpu_read(tr->trace_buffer.data->ftrace_ignore_pid))
189 op->saved_func(ip, parent_ip, op, regs);
193 * clear_ftrace_function - reset the ftrace function
195 * This NULLs the ftrace function and in essence stops
196 * tracing. There may be lag
198 void clear_ftrace_function(void)
200 ftrace_trace_function = ftrace_stub;
203 static void per_cpu_ops_disable_all(struct ftrace_ops *ops)
207 for_each_possible_cpu(cpu)
208 *per_cpu_ptr(ops->disabled, cpu) = 1;
211 static int per_cpu_ops_alloc(struct ftrace_ops *ops)
213 int __percpu *disabled;
215 if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)))
218 disabled = alloc_percpu(int);
222 ops->disabled = disabled;
223 per_cpu_ops_disable_all(ops);
227 static void ftrace_sync(struct work_struct *work)
230 * This function is just a stub to implement a hard force
231 * of synchronize_sched(). This requires synchronizing
232 * tasks even in userspace and idle.
234 * Yes, function tracing is rude.
238 static void ftrace_sync_ipi(void *data)
240 /* Probably not needed, but do it anyway */
244 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
245 static void update_function_graph_func(void);
247 /* Both enabled by default (can be cleared by function_graph tracer flags */
248 static bool fgraph_sleep_time = true;
249 static bool fgraph_graph_time = true;
252 static inline void update_function_graph_func(void) { }
256 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
259 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
260 * then it needs to call the list anyway.
262 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU |
263 FTRACE_OPS_FL_RCU) || FTRACE_FORCE_LIST_FUNC)
264 return ftrace_ops_list_func;
266 return ftrace_ops_get_func(ops);
269 static void update_ftrace_function(void)
274 * Prepare the ftrace_ops that the arch callback will use.
275 * If there's only one ftrace_ops registered, the ftrace_ops_list
276 * will point to the ops we want.
278 set_function_trace_op = ftrace_ops_list;
280 /* If there's no ftrace_ops registered, just call the stub function */
281 if (ftrace_ops_list == &ftrace_list_end) {
285 * If we are at the end of the list and this ops is
286 * recursion safe and not dynamic and the arch supports passing ops,
287 * then have the mcount trampoline call the function directly.
289 } else if (ftrace_ops_list->next == &ftrace_list_end) {
290 func = ftrace_ops_get_list_func(ftrace_ops_list);
293 /* Just use the default ftrace_ops */
294 set_function_trace_op = &ftrace_list_end;
295 func = ftrace_ops_list_func;
298 update_function_graph_func();
300 /* If there's no change, then do nothing more here */
301 if (ftrace_trace_function == func)
305 * If we are using the list function, it doesn't care
306 * about the function_trace_ops.
308 if (func == ftrace_ops_list_func) {
309 ftrace_trace_function = func;
311 * Don't even bother setting function_trace_ops,
312 * it would be racy to do so anyway.
317 #ifndef CONFIG_DYNAMIC_FTRACE
319 * For static tracing, we need to be a bit more careful.
320 * The function change takes affect immediately. Thus,
321 * we need to coorditate the setting of the function_trace_ops
322 * with the setting of the ftrace_trace_function.
324 * Set the function to the list ops, which will call the
325 * function we want, albeit indirectly, but it handles the
326 * ftrace_ops and doesn't depend on function_trace_op.
328 ftrace_trace_function = ftrace_ops_list_func;
330 * Make sure all CPUs see this. Yes this is slow, but static
331 * tracing is slow and nasty to have enabled.
333 schedule_on_each_cpu(ftrace_sync);
334 /* Now all cpus are using the list ops. */
335 function_trace_op = set_function_trace_op;
336 /* Make sure the function_trace_op is visible on all CPUs */
338 /* Nasty way to force a rmb on all cpus */
339 smp_call_function(ftrace_sync_ipi, NULL, 1);
340 /* OK, we are all set to update the ftrace_trace_function now! */
341 #endif /* !CONFIG_DYNAMIC_FTRACE */
343 ftrace_trace_function = func;
346 int using_ftrace_ops_list_func(void)
348 return ftrace_trace_function == ftrace_ops_list_func;
351 static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
355 * We are entering ops into the list but another
356 * CPU might be walking that list. We need to make sure
357 * the ops->next pointer is valid before another CPU sees
358 * the ops pointer included into the list.
360 rcu_assign_pointer(*list, ops);
363 static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
365 struct ftrace_ops **p;
368 * If we are removing the last function, then simply point
369 * to the ftrace_stub.
371 if (*list == ops && ops->next == &ftrace_list_end) {
372 *list = &ftrace_list_end;
376 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
387 static void ftrace_update_trampoline(struct ftrace_ops *ops);
389 static int __register_ftrace_function(struct ftrace_ops *ops)
391 if (ops->flags & FTRACE_OPS_FL_DELETED)
394 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
397 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
399 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
400 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
401 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
403 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
404 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
407 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
408 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
411 if (!core_kernel_data((unsigned long)ops))
412 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
414 if (ops->flags & FTRACE_OPS_FL_PER_CPU) {
415 if (per_cpu_ops_alloc(ops))
419 add_ftrace_ops(&ftrace_ops_list, ops);
421 /* Always save the function, and reset at unregistering */
422 ops->saved_func = ops->func;
424 if (ftrace_pids_enabled(ops))
425 ops->func = ftrace_pid_func;
427 ftrace_update_trampoline(ops);
430 update_ftrace_function();
435 static int __unregister_ftrace_function(struct ftrace_ops *ops)
439 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
442 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
448 update_ftrace_function();
450 ops->func = ops->saved_func;
455 static void ftrace_update_pid_func(void)
457 struct ftrace_ops *op;
459 /* Only do something if we are tracing something */
460 if (ftrace_trace_function == ftrace_stub)
463 do_for_each_ftrace_op(op, ftrace_ops_list) {
464 if (op->flags & FTRACE_OPS_FL_PID) {
465 op->func = ftrace_pids_enabled(op) ?
466 ftrace_pid_func : op->saved_func;
467 ftrace_update_trampoline(op);
469 } while_for_each_ftrace_op(op);
471 update_ftrace_function();
474 #ifdef CONFIG_FUNCTION_PROFILER
475 struct ftrace_profile {
476 struct hlist_node node;
478 unsigned long counter;
479 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
480 unsigned long long time;
481 unsigned long long time_squared;
485 struct ftrace_profile_page {
486 struct ftrace_profile_page *next;
488 struct ftrace_profile records[];
491 struct ftrace_profile_stat {
493 struct hlist_head *hash;
494 struct ftrace_profile_page *pages;
495 struct ftrace_profile_page *start;
496 struct tracer_stat stat;
499 #define PROFILE_RECORDS_SIZE \
500 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
502 #define PROFILES_PER_PAGE \
503 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
505 static int ftrace_profile_enabled __read_mostly;
507 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
508 static DEFINE_MUTEX(ftrace_profile_lock);
510 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
512 #define FTRACE_PROFILE_HASH_BITS 10
513 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
516 function_stat_next(void *v, int idx)
518 struct ftrace_profile *rec = v;
519 struct ftrace_profile_page *pg;
521 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
527 if ((void *)rec >= (void *)&pg->records[pg->index]) {
531 rec = &pg->records[0];
539 static void *function_stat_start(struct tracer_stat *trace)
541 struct ftrace_profile_stat *stat =
542 container_of(trace, struct ftrace_profile_stat, stat);
544 if (!stat || !stat->start)
547 return function_stat_next(&stat->start->records[0], 0);
550 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
551 /* function graph compares on total time */
552 static int function_stat_cmp(void *p1, void *p2)
554 struct ftrace_profile *a = p1;
555 struct ftrace_profile *b = p2;
557 if (a->time < b->time)
559 if (a->time > b->time)
565 /* not function graph compares against hits */
566 static int function_stat_cmp(void *p1, void *p2)
568 struct ftrace_profile *a = p1;
569 struct ftrace_profile *b = p2;
571 if (a->counter < b->counter)
573 if (a->counter > b->counter)
580 static int function_stat_headers(struct seq_file *m)
582 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
583 seq_puts(m, " Function "
586 "--- ---- --- ---\n");
588 seq_puts(m, " Function Hit\n"
594 static int function_stat_show(struct seq_file *m, void *v)
596 struct ftrace_profile *rec = v;
597 char str[KSYM_SYMBOL_LEN];
599 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
600 static struct trace_seq s;
601 unsigned long long avg;
602 unsigned long long stddev;
604 mutex_lock(&ftrace_profile_lock);
606 /* we raced with function_profile_reset() */
607 if (unlikely(rec->counter == 0)) {
612 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
614 do_div(avg, rec->counter);
615 if (tracing_thresh && (avg < tracing_thresh))
619 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
620 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
622 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
625 /* Sample standard deviation (s^2) */
626 if (rec->counter <= 1)
630 * Apply Welford's method:
631 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
633 stddev = rec->counter * rec->time_squared -
634 rec->time * rec->time;
637 * Divide only 1000 for ns^2 -> us^2 conversion.
638 * trace_print_graph_duration will divide 1000 again.
640 do_div(stddev, rec->counter * (rec->counter - 1) * 1000);
644 trace_print_graph_duration(rec->time, &s);
645 trace_seq_puts(&s, " ");
646 trace_print_graph_duration(avg, &s);
647 trace_seq_puts(&s, " ");
648 trace_print_graph_duration(stddev, &s);
649 trace_print_seq(m, &s);
653 mutex_unlock(&ftrace_profile_lock);
658 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
660 struct ftrace_profile_page *pg;
662 pg = stat->pages = stat->start;
665 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
670 memset(stat->hash, 0,
671 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
674 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
676 struct ftrace_profile_page *pg;
681 /* If we already allocated, do nothing */
685 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
689 #ifdef CONFIG_DYNAMIC_FTRACE
690 functions = ftrace_update_tot_cnt;
693 * We do not know the number of functions that exist because
694 * dynamic tracing is what counts them. With past experience
695 * we have around 20K functions. That should be more than enough.
696 * It is highly unlikely we will execute every function in
702 pg = stat->start = stat->pages;
704 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
706 for (i = 1; i < pages; i++) {
707 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
718 unsigned long tmp = (unsigned long)pg;
730 static int ftrace_profile_init_cpu(int cpu)
732 struct ftrace_profile_stat *stat;
735 stat = &per_cpu(ftrace_profile_stats, cpu);
738 /* If the profile is already created, simply reset it */
739 ftrace_profile_reset(stat);
744 * We are profiling all functions, but usually only a few thousand
745 * functions are hit. We'll make a hash of 1024 items.
747 size = FTRACE_PROFILE_HASH_SIZE;
749 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
754 /* Preallocate the function profiling pages */
755 if (ftrace_profile_pages_init(stat) < 0) {
764 static int ftrace_profile_init(void)
769 for_each_possible_cpu(cpu) {
770 ret = ftrace_profile_init_cpu(cpu);
778 /* interrupts must be disabled */
779 static struct ftrace_profile *
780 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
782 struct ftrace_profile *rec;
783 struct hlist_head *hhd;
786 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
787 hhd = &stat->hash[key];
789 if (hlist_empty(hhd))
792 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
800 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
801 struct ftrace_profile *rec)
805 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
806 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
810 * The memory is already allocated, this simply finds a new record to use.
812 static struct ftrace_profile *
813 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
815 struct ftrace_profile *rec = NULL;
817 /* prevent recursion (from NMIs) */
818 if (atomic_inc_return(&stat->disabled) != 1)
822 * Try to find the function again since an NMI
823 * could have added it
825 rec = ftrace_find_profiled_func(stat, ip);
829 if (stat->pages->index == PROFILES_PER_PAGE) {
830 if (!stat->pages->next)
832 stat->pages = stat->pages->next;
835 rec = &stat->pages->records[stat->pages->index++];
837 ftrace_add_profile(stat, rec);
840 atomic_dec(&stat->disabled);
846 function_profile_call(unsigned long ip, unsigned long parent_ip,
847 struct ftrace_ops *ops, struct pt_regs *regs)
849 struct ftrace_profile_stat *stat;
850 struct ftrace_profile *rec;
853 if (!ftrace_profile_enabled)
856 local_irq_save(flags);
858 stat = this_cpu_ptr(&ftrace_profile_stats);
859 if (!stat->hash || !ftrace_profile_enabled)
862 rec = ftrace_find_profiled_func(stat, ip);
864 rec = ftrace_profile_alloc(stat, ip);
871 local_irq_restore(flags);
874 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
875 static int profile_graph_entry(struct ftrace_graph_ent *trace)
877 int index = trace->depth;
879 function_profile_call(trace->func, 0, NULL, NULL);
881 if (index >= 0 && index < FTRACE_RETFUNC_DEPTH)
882 current->ret_stack[index].subtime = 0;
887 static void profile_graph_return(struct ftrace_graph_ret *trace)
889 struct ftrace_profile_stat *stat;
890 unsigned long long calltime;
891 struct ftrace_profile *rec;
894 local_irq_save(flags);
895 stat = this_cpu_ptr(&ftrace_profile_stats);
896 if (!stat->hash || !ftrace_profile_enabled)
899 /* If the calltime was zero'd ignore it */
900 if (!trace->calltime)
903 calltime = trace->rettime - trace->calltime;
905 if (!fgraph_graph_time) {
908 index = trace->depth;
910 /* Append this call time to the parent time to subtract */
912 current->ret_stack[index - 1].subtime += calltime;
914 if (current->ret_stack[index].subtime < calltime)
915 calltime -= current->ret_stack[index].subtime;
920 rec = ftrace_find_profiled_func(stat, trace->func);
922 rec->time += calltime;
923 rec->time_squared += calltime * calltime;
927 local_irq_restore(flags);
930 static int register_ftrace_profiler(void)
932 return register_ftrace_graph(&profile_graph_return,
933 &profile_graph_entry);
936 static void unregister_ftrace_profiler(void)
938 unregister_ftrace_graph();
941 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
942 .func = function_profile_call,
943 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
944 INIT_OPS_HASH(ftrace_profile_ops)
947 static int register_ftrace_profiler(void)
949 return register_ftrace_function(&ftrace_profile_ops);
952 static void unregister_ftrace_profiler(void)
954 unregister_ftrace_function(&ftrace_profile_ops);
956 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
959 ftrace_profile_write(struct file *filp, const char __user *ubuf,
960 size_t cnt, loff_t *ppos)
965 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
971 mutex_lock(&ftrace_profile_lock);
972 if (ftrace_profile_enabled ^ val) {
974 ret = ftrace_profile_init();
980 ret = register_ftrace_profiler();
985 ftrace_profile_enabled = 1;
987 ftrace_profile_enabled = 0;
989 * unregister_ftrace_profiler calls stop_machine
990 * so this acts like an synchronize_sched.
992 unregister_ftrace_profiler();
996 mutex_unlock(&ftrace_profile_lock);
1004 ftrace_profile_read(struct file *filp, char __user *ubuf,
1005 size_t cnt, loff_t *ppos)
1007 char buf[64]; /* big enough to hold a number */
1010 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
1011 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1014 static const struct file_operations ftrace_profile_fops = {
1015 .open = tracing_open_generic,
1016 .read = ftrace_profile_read,
1017 .write = ftrace_profile_write,
1018 .llseek = default_llseek,
1021 /* used to initialize the real stat files */
1022 static struct tracer_stat function_stats __initdata = {
1023 .name = "functions",
1024 .stat_start = function_stat_start,
1025 .stat_next = function_stat_next,
1026 .stat_cmp = function_stat_cmp,
1027 .stat_headers = function_stat_headers,
1028 .stat_show = function_stat_show
1031 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1033 struct ftrace_profile_stat *stat;
1034 struct dentry *entry;
1039 for_each_possible_cpu(cpu) {
1040 stat = &per_cpu(ftrace_profile_stats, cpu);
1042 name = kasprintf(GFP_KERNEL, "function%d", cpu);
1045 * The files created are permanent, if something happens
1046 * we still do not free memory.
1049 "Could not allocate stat file for cpu %d\n",
1053 stat->stat = function_stats;
1054 stat->stat.name = name;
1055 ret = register_stat_tracer(&stat->stat);
1058 "Could not register function stat for cpu %d\n",
1065 entry = tracefs_create_file("function_profile_enabled", 0644,
1066 d_tracer, NULL, &ftrace_profile_fops);
1068 pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
1071 #else /* CONFIG_FUNCTION_PROFILER */
1072 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1075 #endif /* CONFIG_FUNCTION_PROFILER */
1077 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1079 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1080 static int ftrace_graph_active;
1082 # define ftrace_graph_active 0
1085 #ifdef CONFIG_DYNAMIC_FTRACE
1087 static struct ftrace_ops *removed_ops;
1090 * Set when doing a global update, like enabling all recs or disabling them.
1091 * It is not set when just updating a single ftrace_ops.
1093 static bool update_all_ops;
1095 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1096 # error Dynamic ftrace depends on MCOUNT_RECORD
1099 struct ftrace_func_entry {
1100 struct hlist_node hlist;
1104 struct ftrace_func_probe {
1105 struct ftrace_probe_ops *probe_ops;
1106 struct ftrace_ops ops;
1107 struct trace_array *tr;
1108 struct list_head list;
1114 * We make these constant because no one should touch them,
1115 * but they are used as the default "empty hash", to avoid allocating
1116 * it all the time. These are in a read only section such that if
1117 * anyone does try to modify it, it will cause an exception.
1119 static const struct hlist_head empty_buckets[1];
1120 static const struct ftrace_hash empty_hash = {
1121 .buckets = (struct hlist_head *)empty_buckets,
1123 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1125 static struct ftrace_ops global_ops = {
1126 .func = ftrace_stub,
1127 .local_hash.notrace_hash = EMPTY_HASH,
1128 .local_hash.filter_hash = EMPTY_HASH,
1129 INIT_OPS_HASH(global_ops)
1130 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
1131 FTRACE_OPS_FL_INITIALIZED |
1136 * This is used by __kernel_text_address() to return true if the
1137 * address is on a dynamically allocated trampoline that would
1138 * not return true for either core_kernel_text() or
1139 * is_module_text_address().
1141 bool is_ftrace_trampoline(unsigned long addr)
1143 struct ftrace_ops *op;
1147 * Some of the ops may be dynamically allocated,
1148 * they are freed after a synchronize_sched().
1150 preempt_disable_notrace();
1152 do_for_each_ftrace_op(op, ftrace_ops_list) {
1154 * This is to check for dynamically allocated trampolines.
1155 * Trampolines that are in kernel text will have
1156 * core_kernel_text() return true.
1158 if (op->trampoline && op->trampoline_size)
1159 if (addr >= op->trampoline &&
1160 addr < op->trampoline + op->trampoline_size) {
1164 } while_for_each_ftrace_op(op);
1167 preempt_enable_notrace();
1172 struct ftrace_page {
1173 struct ftrace_page *next;
1174 struct dyn_ftrace *records;
1179 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1180 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1182 /* estimate from running different kernels */
1183 #define NR_TO_INIT 10000
1185 static struct ftrace_page *ftrace_pages_start;
1186 static struct ftrace_page *ftrace_pages;
1188 static __always_inline unsigned long
1189 ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1191 if (hash->size_bits > 0)
1192 return hash_long(ip, hash->size_bits);
1197 /* Only use this function if ftrace_hash_empty() has already been tested */
1198 static __always_inline struct ftrace_func_entry *
1199 __ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1202 struct ftrace_func_entry *entry;
1203 struct hlist_head *hhd;
1205 key = ftrace_hash_key(hash, ip);
1206 hhd = &hash->buckets[key];
1208 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1209 if (entry->ip == ip)
1216 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1217 * @hash: The hash to look at
1218 * @ip: The instruction pointer to test
1220 * Search a given @hash to see if a given instruction pointer (@ip)
1223 * Returns the entry that holds the @ip if found. NULL otherwise.
1225 struct ftrace_func_entry *
1226 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1228 if (ftrace_hash_empty(hash))
1231 return __ftrace_lookup_ip(hash, ip);
1234 static void __add_hash_entry(struct ftrace_hash *hash,
1235 struct ftrace_func_entry *entry)
1237 struct hlist_head *hhd;
1240 key = ftrace_hash_key(hash, entry->ip);
1241 hhd = &hash->buckets[key];
1242 hlist_add_head(&entry->hlist, hhd);
1246 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1248 struct ftrace_func_entry *entry;
1250 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1255 __add_hash_entry(hash, entry);
1261 free_hash_entry(struct ftrace_hash *hash,
1262 struct ftrace_func_entry *entry)
1264 hlist_del(&entry->hlist);
1270 remove_hash_entry(struct ftrace_hash *hash,
1271 struct ftrace_func_entry *entry)
1273 hlist_del_rcu(&entry->hlist);
1277 static void ftrace_hash_clear(struct ftrace_hash *hash)
1279 struct hlist_head *hhd;
1280 struct hlist_node *tn;
1281 struct ftrace_func_entry *entry;
1282 int size = 1 << hash->size_bits;
1288 for (i = 0; i < size; i++) {
1289 hhd = &hash->buckets[i];
1290 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1291 free_hash_entry(hash, entry);
1293 FTRACE_WARN_ON(hash->count);
1296 static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1298 list_del(&ftrace_mod->list);
1299 kfree(ftrace_mod->module);
1300 kfree(ftrace_mod->func);
1304 static void clear_ftrace_mod_list(struct list_head *head)
1306 struct ftrace_mod_load *p, *n;
1308 /* stack tracer isn't supported yet */
1312 mutex_lock(&ftrace_lock);
1313 list_for_each_entry_safe(p, n, head, list)
1315 mutex_unlock(&ftrace_lock);
1318 static void free_ftrace_hash(struct ftrace_hash *hash)
1320 if (!hash || hash == EMPTY_HASH)
1322 ftrace_hash_clear(hash);
1323 kfree(hash->buckets);
1327 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1329 struct ftrace_hash *hash;
1331 hash = container_of(rcu, struct ftrace_hash, rcu);
1332 free_ftrace_hash(hash);
1335 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1337 if (!hash || hash == EMPTY_HASH)
1339 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1342 void ftrace_free_filter(struct ftrace_ops *ops)
1344 ftrace_ops_init(ops);
1345 free_ftrace_hash(ops->func_hash->filter_hash);
1346 free_ftrace_hash(ops->func_hash->notrace_hash);
1349 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1351 struct ftrace_hash *hash;
1354 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1358 size = 1 << size_bits;
1359 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1361 if (!hash->buckets) {
1366 hash->size_bits = size_bits;
1372 static int ftrace_add_mod(struct trace_array *tr,
1373 const char *func, const char *module,
1376 struct ftrace_mod_load *ftrace_mod;
1377 struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1379 ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1383 ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1384 ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1385 ftrace_mod->enable = enable;
1387 if (!ftrace_mod->func || !ftrace_mod->module)
1390 list_add(&ftrace_mod->list, mod_head);
1395 free_ftrace_mod(ftrace_mod);
1400 static struct ftrace_hash *
1401 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1403 struct ftrace_func_entry *entry;
1404 struct ftrace_hash *new_hash;
1409 new_hash = alloc_ftrace_hash(size_bits);
1414 new_hash->flags = hash->flags;
1417 if (ftrace_hash_empty(hash))
1420 size = 1 << hash->size_bits;
1421 for (i = 0; i < size; i++) {
1422 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1423 ret = add_hash_entry(new_hash, entry->ip);
1429 FTRACE_WARN_ON(new_hash->count != hash->count);
1434 free_ftrace_hash(new_hash);
1439 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1441 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1443 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1444 struct ftrace_hash *new_hash);
1446 static struct ftrace_hash *
1447 __ftrace_hash_move(struct ftrace_hash *src)
1449 struct ftrace_func_entry *entry;
1450 struct hlist_node *tn;
1451 struct hlist_head *hhd;
1452 struct ftrace_hash *new_hash;
1453 int size = src->count;
1458 * If the new source is empty, just return the empty_hash.
1460 if (ftrace_hash_empty(src))
1464 * Make the hash size about 1/2 the # found
1466 for (size /= 2; size; size >>= 1)
1469 /* Don't allocate too much */
1470 if (bits > FTRACE_HASH_MAX_BITS)
1471 bits = FTRACE_HASH_MAX_BITS;
1473 new_hash = alloc_ftrace_hash(bits);
1477 new_hash->flags = src->flags;
1479 size = 1 << src->size_bits;
1480 for (i = 0; i < size; i++) {
1481 hhd = &src->buckets[i];
1482 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1483 remove_hash_entry(src, entry);
1484 __add_hash_entry(new_hash, entry);
1492 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1493 struct ftrace_hash **dst, struct ftrace_hash *src)
1495 struct ftrace_hash *new_hash;
1498 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1499 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1502 new_hash = __ftrace_hash_move(src);
1506 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1508 /* IPMODIFY should be updated only when filter_hash updating */
1509 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1511 free_ftrace_hash(new_hash);
1517 * Remove the current set, update the hash and add
1520 ftrace_hash_rec_disable_modify(ops, enable);
1522 rcu_assign_pointer(*dst, new_hash);
1524 ftrace_hash_rec_enable_modify(ops, enable);
1529 static bool hash_contains_ip(unsigned long ip,
1530 struct ftrace_ops_hash *hash)
1533 * The function record is a match if it exists in the filter
1534 * hash and not in the notrace hash. Note, an emty hash is
1535 * considered a match for the filter hash, but an empty
1536 * notrace hash is considered not in the notrace hash.
1538 return (ftrace_hash_empty(hash->filter_hash) ||
1539 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1540 (ftrace_hash_empty(hash->notrace_hash) ||
1541 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1545 * Test the hashes for this ops to see if we want to call
1546 * the ops->func or not.
1548 * It's a match if the ip is in the ops->filter_hash or
1549 * the filter_hash does not exist or is empty,
1551 * the ip is not in the ops->notrace_hash.
1553 * This needs to be called with preemption disabled as
1554 * the hashes are freed with call_rcu_sched().
1557 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1559 struct ftrace_ops_hash hash;
1562 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1564 * There's a small race when adding ops that the ftrace handler
1565 * that wants regs, may be called without them. We can not
1566 * allow that handler to be called if regs is NULL.
1568 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1572 hash.filter_hash = rcu_dereference_raw_notrace(ops->func_hash->filter_hash);
1573 hash.notrace_hash = rcu_dereference_raw_notrace(ops->func_hash->notrace_hash);
1575 if (hash_contains_ip(ip, &hash))
1584 * This is a double for. Do not use 'break' to break out of the loop,
1585 * you must use a goto.
1587 #define do_for_each_ftrace_rec(pg, rec) \
1588 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1590 for (_____i = 0; _____i < pg->index; _____i++) { \
1591 rec = &pg->records[_____i];
1593 #define while_for_each_ftrace_rec() \
1598 static int ftrace_cmp_recs(const void *a, const void *b)
1600 const struct dyn_ftrace *key = a;
1601 const struct dyn_ftrace *rec = b;
1603 if (key->flags < rec->ip)
1605 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1611 * ftrace_location_range - return the first address of a traced location
1612 * if it touches the given ip range
1613 * @start: start of range to search.
1614 * @end: end of range to search (inclusive). @end points to the last byte
1617 * Returns rec->ip if the related ftrace location is a least partly within
1618 * the given address range. That is, the first address of the instruction
1619 * that is either a NOP or call to the function tracer. It checks the ftrace
1620 * internal tables to determine if the address belongs or not.
1622 unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1624 struct ftrace_page *pg;
1625 struct dyn_ftrace *rec;
1626 struct dyn_ftrace key;
1629 key.flags = end; /* overload flags, as it is unsigned long */
1631 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1632 if (end < pg->records[0].ip ||
1633 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1635 rec = bsearch(&key, pg->records, pg->index,
1636 sizeof(struct dyn_ftrace),
1646 * ftrace_location - return true if the ip giving is a traced location
1647 * @ip: the instruction pointer to check
1649 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1650 * That is, the instruction that is either a NOP or call to
1651 * the function tracer. It checks the ftrace internal tables to
1652 * determine if the address belongs or not.
1654 unsigned long ftrace_location(unsigned long ip)
1656 return ftrace_location_range(ip, ip);
1660 * ftrace_text_reserved - return true if range contains an ftrace location
1661 * @start: start of range to search
1662 * @end: end of range to search (inclusive). @end points to the last byte to check.
1664 * Returns 1 if @start and @end contains a ftrace location.
1665 * That is, the instruction that is either a NOP or call to
1666 * the function tracer. It checks the ftrace internal tables to
1667 * determine if the address belongs or not.
1669 int ftrace_text_reserved(const void *start, const void *end)
1673 ret = ftrace_location_range((unsigned long)start,
1674 (unsigned long)end);
1679 /* Test if ops registered to this rec needs regs */
1680 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1682 struct ftrace_ops *ops;
1683 bool keep_regs = false;
1685 for (ops = ftrace_ops_list;
1686 ops != &ftrace_list_end; ops = ops->next) {
1687 /* pass rec in as regs to have non-NULL val */
1688 if (ftrace_ops_test(ops, rec->ip, rec)) {
1689 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1699 static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1703 struct ftrace_hash *hash;
1704 struct ftrace_hash *other_hash;
1705 struct ftrace_page *pg;
1706 struct dyn_ftrace *rec;
1707 bool update = false;
1711 /* Only update if the ops has been registered */
1712 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1716 * In the filter_hash case:
1717 * If the count is zero, we update all records.
1718 * Otherwise we just update the items in the hash.
1720 * In the notrace_hash case:
1721 * We enable the update in the hash.
1722 * As disabling notrace means enabling the tracing,
1723 * and enabling notrace means disabling, the inc variable
1727 hash = ops->func_hash->filter_hash;
1728 other_hash = ops->func_hash->notrace_hash;
1729 if (ftrace_hash_empty(hash))
1733 hash = ops->func_hash->notrace_hash;
1734 other_hash = ops->func_hash->filter_hash;
1736 * If the notrace hash has no items,
1737 * then there's nothing to do.
1739 if (ftrace_hash_empty(hash))
1743 do_for_each_ftrace_rec(pg, rec) {
1744 int in_other_hash = 0;
1748 if (rec->flags & FTRACE_FL_DISABLED)
1753 * Only the filter_hash affects all records.
1754 * Update if the record is not in the notrace hash.
1756 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1759 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1760 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1763 * If filter_hash is set, we want to match all functions
1764 * that are in the hash but not in the other hash.
1766 * If filter_hash is not set, then we are decrementing.
1767 * That means we match anything that is in the hash
1768 * and also in the other_hash. That is, we need to turn
1769 * off functions in the other hash because they are disabled
1772 if (filter_hash && in_hash && !in_other_hash)
1774 else if (!filter_hash && in_hash &&
1775 (in_other_hash || ftrace_hash_empty(other_hash)))
1783 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1787 * If there's only a single callback registered to a
1788 * function, and the ops has a trampoline registered
1789 * for it, then we can call it directly.
1791 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1792 rec->flags |= FTRACE_FL_TRAMP;
1795 * If we are adding another function callback
1796 * to this function, and the previous had a
1797 * custom trampoline in use, then we need to go
1798 * back to the default trampoline.
1800 rec->flags &= ~FTRACE_FL_TRAMP;
1803 * If any ops wants regs saved for this function
1804 * then all ops will get saved regs.
1806 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1807 rec->flags |= FTRACE_FL_REGS;
1809 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1814 * If the rec had REGS enabled and the ops that is
1815 * being removed had REGS set, then see if there is
1816 * still any ops for this record that wants regs.
1817 * If not, we can stop recording them.
1819 if (ftrace_rec_count(rec) > 0 &&
1820 rec->flags & FTRACE_FL_REGS &&
1821 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1822 if (!test_rec_ops_needs_regs(rec))
1823 rec->flags &= ~FTRACE_FL_REGS;
1827 * If the rec had TRAMP enabled, then it needs to
1828 * be cleared. As TRAMP can only be enabled iff
1829 * there is only a single ops attached to it.
1830 * In otherwords, always disable it on decrementing.
1831 * In the future, we may set it if rec count is
1832 * decremented to one, and the ops that is left
1835 rec->flags &= ~FTRACE_FL_TRAMP;
1838 * flags will be cleared in ftrace_check_record()
1839 * if rec count is zero.
1844 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1845 update |= ftrace_test_record(rec, 1) != FTRACE_UPDATE_IGNORE;
1847 /* Shortcut, if we handled all records, we are done. */
1848 if (!all && count == hash->count)
1850 } while_for_each_ftrace_rec();
1855 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1858 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1861 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1864 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1867 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1868 int filter_hash, int inc)
1870 struct ftrace_ops *op;
1872 __ftrace_hash_rec_update(ops, filter_hash, inc);
1874 if (ops->func_hash != &global_ops.local_hash)
1878 * If the ops shares the global_ops hash, then we need to update
1879 * all ops that are enabled and use this hash.
1881 do_for_each_ftrace_op(op, ftrace_ops_list) {
1885 if (op->func_hash == &global_ops.local_hash)
1886 __ftrace_hash_rec_update(op, filter_hash, inc);
1887 } while_for_each_ftrace_op(op);
1890 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1893 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1896 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1899 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1903 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1904 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1905 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1906 * Note that old_hash and new_hash has below meanings
1907 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1908 * - If the hash is EMPTY_HASH, it hits nothing
1909 * - Anything else hits the recs which match the hash entries.
1911 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1912 struct ftrace_hash *old_hash,
1913 struct ftrace_hash *new_hash)
1915 struct ftrace_page *pg;
1916 struct dyn_ftrace *rec, *end = NULL;
1919 /* Only update if the ops has been registered */
1920 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1923 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1927 * Since the IPMODIFY is a very address sensitive action, we do not
1928 * allow ftrace_ops to set all functions to new hash.
1930 if (!new_hash || !old_hash)
1933 /* Update rec->flags */
1934 do_for_each_ftrace_rec(pg, rec) {
1936 if (rec->flags & FTRACE_FL_DISABLED)
1939 /* We need to update only differences of filter_hash */
1940 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1941 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1942 if (in_old == in_new)
1946 /* New entries must ensure no others are using it */
1947 if (rec->flags & FTRACE_FL_IPMODIFY)
1949 rec->flags |= FTRACE_FL_IPMODIFY;
1950 } else /* Removed entry */
1951 rec->flags &= ~FTRACE_FL_IPMODIFY;
1952 } while_for_each_ftrace_rec();
1959 /* Roll back what we did above */
1960 do_for_each_ftrace_rec(pg, rec) {
1962 if (rec->flags & FTRACE_FL_DISABLED)
1968 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1969 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1970 if (in_old == in_new)
1974 rec->flags &= ~FTRACE_FL_IPMODIFY;
1976 rec->flags |= FTRACE_FL_IPMODIFY;
1977 } while_for_each_ftrace_rec();
1983 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1985 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1987 if (ftrace_hash_empty(hash))
1990 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1993 /* Disabling always succeeds */
1994 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1996 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1998 if (ftrace_hash_empty(hash))
2001 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
2004 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
2005 struct ftrace_hash *new_hash)
2007 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
2009 if (ftrace_hash_empty(old_hash))
2012 if (ftrace_hash_empty(new_hash))
2015 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
2018 static void print_ip_ins(const char *fmt, const unsigned char *p)
2022 printk(KERN_CONT "%s", fmt);
2024 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
2025 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
2028 static struct ftrace_ops *
2029 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
2030 static struct ftrace_ops *
2031 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
2033 enum ftrace_bug_type ftrace_bug_type;
2034 const void *ftrace_expected;
2036 static void print_bug_type(void)
2038 switch (ftrace_bug_type) {
2039 case FTRACE_BUG_UNKNOWN:
2041 case FTRACE_BUG_INIT:
2042 pr_info("Initializing ftrace call sites\n");
2044 case FTRACE_BUG_NOP:
2045 pr_info("Setting ftrace call site to NOP\n");
2047 case FTRACE_BUG_CALL:
2048 pr_info("Setting ftrace call site to call ftrace function\n");
2050 case FTRACE_BUG_UPDATE:
2051 pr_info("Updating ftrace call site to call a different ftrace function\n");
2057 * ftrace_bug - report and shutdown function tracer
2058 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2059 * @rec: The record that failed
2061 * The arch code that enables or disables the function tracing
2062 * can call ftrace_bug() when it has detected a problem in
2063 * modifying the code. @failed should be one of either:
2064 * EFAULT - if the problem happens on reading the @ip address
2065 * EINVAL - if what is read at @ip is not what was expected
2066 * EPERM - if the problem happens on writting to the @ip address
2068 void ftrace_bug(int failed, struct dyn_ftrace *rec)
2070 unsigned long ip = rec ? rec->ip : 0;
2074 FTRACE_WARN_ON_ONCE(1);
2075 pr_info("ftrace faulted on modifying ");
2079 FTRACE_WARN_ON_ONCE(1);
2080 pr_info("ftrace failed to modify ");
2082 print_ip_ins(" actual: ", (unsigned char *)ip);
2084 if (ftrace_expected) {
2085 print_ip_ins(" expected: ", ftrace_expected);
2090 FTRACE_WARN_ON_ONCE(1);
2091 pr_info("ftrace faulted on writing ");
2095 FTRACE_WARN_ON_ONCE(1);
2096 pr_info("ftrace faulted on unknown error ");
2101 struct ftrace_ops *ops = NULL;
2103 pr_info("ftrace record flags: %lx\n", rec->flags);
2104 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2105 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2106 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2107 ops = ftrace_find_tramp_ops_any(rec);
2110 pr_cont("\ttramp: %pS (%pS)",
2111 (void *)ops->trampoline,
2113 ops = ftrace_find_tramp_ops_next(rec, ops);
2116 pr_cont("\ttramp: ERROR!");
2119 ip = ftrace_get_addr_curr(rec);
2120 pr_cont("\n expected tramp: %lx\n", ip);
2124 static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
2126 unsigned long flag = 0UL;
2128 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2130 if (rec->flags & FTRACE_FL_DISABLED)
2131 return FTRACE_UPDATE_IGNORE;
2134 * If we are updating calls:
2136 * If the record has a ref count, then we need to enable it
2137 * because someone is using it.
2139 * Otherwise we make sure its disabled.
2141 * If we are disabling calls, then disable all records that
2144 if (enable && ftrace_rec_count(rec))
2145 flag = FTRACE_FL_ENABLED;
2148 * If enabling and the REGS flag does not match the REGS_EN, or
2149 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2150 * this record. Set flags to fail the compare against ENABLED.
2153 if (!(rec->flags & FTRACE_FL_REGS) !=
2154 !(rec->flags & FTRACE_FL_REGS_EN))
2155 flag |= FTRACE_FL_REGS;
2157 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2158 !(rec->flags & FTRACE_FL_TRAMP_EN))
2159 flag |= FTRACE_FL_TRAMP;
2162 /* If the state of this record hasn't changed, then do nothing */
2163 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2164 return FTRACE_UPDATE_IGNORE;
2167 /* Save off if rec is being enabled (for return value) */
2168 flag ^= rec->flags & FTRACE_FL_ENABLED;
2171 rec->flags |= FTRACE_FL_ENABLED;
2172 if (flag & FTRACE_FL_REGS) {
2173 if (rec->flags & FTRACE_FL_REGS)
2174 rec->flags |= FTRACE_FL_REGS_EN;
2176 rec->flags &= ~FTRACE_FL_REGS_EN;
2178 if (flag & FTRACE_FL_TRAMP) {
2179 if (rec->flags & FTRACE_FL_TRAMP)
2180 rec->flags |= FTRACE_FL_TRAMP_EN;
2182 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2187 * If this record is being updated from a nop, then
2188 * return UPDATE_MAKE_CALL.
2190 * return UPDATE_MODIFY_CALL to tell the caller to convert
2191 * from the save regs, to a non-save regs function or
2192 * vice versa, or from a trampoline call.
2194 if (flag & FTRACE_FL_ENABLED) {
2195 ftrace_bug_type = FTRACE_BUG_CALL;
2196 return FTRACE_UPDATE_MAKE_CALL;
2199 ftrace_bug_type = FTRACE_BUG_UPDATE;
2200 return FTRACE_UPDATE_MODIFY_CALL;
2204 /* If there's no more users, clear all flags */
2205 if (!ftrace_rec_count(rec))
2209 * Just disable the record, but keep the ops TRAMP
2210 * and REGS states. The _EN flags must be disabled though.
2212 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2216 ftrace_bug_type = FTRACE_BUG_NOP;
2217 return FTRACE_UPDATE_MAKE_NOP;
2221 * ftrace_update_record, set a record that now is tracing or not
2222 * @rec: the record to update
2223 * @enable: set to 1 if the record is tracing, zero to force disable
2225 * The records that represent all functions that can be traced need
2226 * to be updated when tracing has been enabled.
2228 int ftrace_update_record(struct dyn_ftrace *rec, int enable)
2230 return ftrace_check_record(rec, enable, 1);
2234 * ftrace_test_record, check if the record has been enabled or not
2235 * @rec: the record to test
2236 * @enable: set to 1 to check if enabled, 0 if it is disabled
2238 * The arch code may need to test if a record is already set to
2239 * tracing to determine how to modify the function code that it
2242 int ftrace_test_record(struct dyn_ftrace *rec, int enable)
2244 return ftrace_check_record(rec, enable, 0);
2247 static struct ftrace_ops *
2248 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2250 struct ftrace_ops *op;
2251 unsigned long ip = rec->ip;
2253 do_for_each_ftrace_op(op, ftrace_ops_list) {
2255 if (!op->trampoline)
2258 if (hash_contains_ip(ip, op->func_hash))
2260 } while_for_each_ftrace_op(op);
2265 static struct ftrace_ops *
2266 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2267 struct ftrace_ops *op)
2269 unsigned long ip = rec->ip;
2271 while_for_each_ftrace_op(op) {
2273 if (!op->trampoline)
2276 if (hash_contains_ip(ip, op->func_hash))
2283 static struct ftrace_ops *
2284 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2286 struct ftrace_ops *op;
2287 unsigned long ip = rec->ip;
2290 * Need to check removed ops first.
2291 * If they are being removed, and this rec has a tramp,
2292 * and this rec is in the ops list, then it would be the
2293 * one with the tramp.
2296 if (hash_contains_ip(ip, &removed_ops->old_hash))
2301 * Need to find the current trampoline for a rec.
2302 * Now, a trampoline is only attached to a rec if there
2303 * was a single 'ops' attached to it. But this can be called
2304 * when we are adding another op to the rec or removing the
2305 * current one. Thus, if the op is being added, we can
2306 * ignore it because it hasn't attached itself to the rec
2309 * If an ops is being modified (hooking to different functions)
2310 * then we don't care about the new functions that are being
2311 * added, just the old ones (that are probably being removed).
2313 * If we are adding an ops to a function that already is using
2314 * a trampoline, it needs to be removed (trampolines are only
2315 * for single ops connected), then an ops that is not being
2316 * modified also needs to be checked.
2318 do_for_each_ftrace_op(op, ftrace_ops_list) {
2320 if (!op->trampoline)
2324 * If the ops is being added, it hasn't gotten to
2325 * the point to be removed from this tree yet.
2327 if (op->flags & FTRACE_OPS_FL_ADDING)
2332 * If the ops is being modified and is in the old
2333 * hash, then it is probably being removed from this
2336 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2337 hash_contains_ip(ip, &op->old_hash))
2340 * If the ops is not being added or modified, and it's
2341 * in its normal filter hash, then this must be the one
2344 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2345 hash_contains_ip(ip, op->func_hash))
2348 } while_for_each_ftrace_op(op);
2353 static struct ftrace_ops *
2354 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2356 struct ftrace_ops *op;
2357 unsigned long ip = rec->ip;
2359 do_for_each_ftrace_op(op, ftrace_ops_list) {
2360 /* pass rec in as regs to have non-NULL val */
2361 if (hash_contains_ip(ip, op->func_hash))
2363 } while_for_each_ftrace_op(op);
2369 * ftrace_get_addr_new - Get the call address to set to
2370 * @rec: The ftrace record descriptor
2372 * If the record has the FTRACE_FL_REGS set, that means that it
2373 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2374 * is not not set, then it wants to convert to the normal callback.
2376 * Returns the address of the trampoline to set to
2378 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2380 struct ftrace_ops *ops;
2382 /* Trampolines take precedence over regs */
2383 if (rec->flags & FTRACE_FL_TRAMP) {
2384 ops = ftrace_find_tramp_ops_new(rec);
2385 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2386 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2387 (void *)rec->ip, (void *)rec->ip, rec->flags);
2388 /* Ftrace is shutting down, return anything */
2389 return (unsigned long)FTRACE_ADDR;
2391 return ops->trampoline;
2394 if (rec->flags & FTRACE_FL_REGS)
2395 return (unsigned long)FTRACE_REGS_ADDR;
2397 return (unsigned long)FTRACE_ADDR;
2401 * ftrace_get_addr_curr - Get the call address that is already there
2402 * @rec: The ftrace record descriptor
2404 * The FTRACE_FL_REGS_EN is set when the record already points to
2405 * a function that saves all the regs. Basically the '_EN' version
2406 * represents the current state of the function.
2408 * Returns the address of the trampoline that is currently being called
2410 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2412 struct ftrace_ops *ops;
2414 /* Trampolines take precedence over regs */
2415 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2416 ops = ftrace_find_tramp_ops_curr(rec);
2417 if (FTRACE_WARN_ON(!ops)) {
2418 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2419 (void *)rec->ip, (void *)rec->ip);
2420 /* Ftrace is shutting down, return anything */
2421 return (unsigned long)FTRACE_ADDR;
2423 return ops->trampoline;
2426 if (rec->flags & FTRACE_FL_REGS_EN)
2427 return (unsigned long)FTRACE_REGS_ADDR;
2429 return (unsigned long)FTRACE_ADDR;
2433 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
2435 unsigned long ftrace_old_addr;
2436 unsigned long ftrace_addr;
2439 ftrace_addr = ftrace_get_addr_new(rec);
2441 /* This needs to be done before we call ftrace_update_record */
2442 ftrace_old_addr = ftrace_get_addr_curr(rec);
2444 ret = ftrace_update_record(rec, enable);
2446 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2449 case FTRACE_UPDATE_IGNORE:
2452 case FTRACE_UPDATE_MAKE_CALL:
2453 ftrace_bug_type = FTRACE_BUG_CALL;
2454 return ftrace_make_call(rec, ftrace_addr);
2456 case FTRACE_UPDATE_MAKE_NOP:
2457 ftrace_bug_type = FTRACE_BUG_NOP;
2458 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2460 case FTRACE_UPDATE_MODIFY_CALL:
2461 ftrace_bug_type = FTRACE_BUG_UPDATE;
2462 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2465 return -1; /* unknow ftrace bug */
2468 void __weak ftrace_replace_code(int enable)
2470 struct dyn_ftrace *rec;
2471 struct ftrace_page *pg;
2474 if (unlikely(ftrace_disabled))
2477 do_for_each_ftrace_rec(pg, rec) {
2479 if (rec->flags & FTRACE_FL_DISABLED)
2482 failed = __ftrace_replace_code(rec, enable);
2484 ftrace_bug(failed, rec);
2485 /* Stop processing */
2488 } while_for_each_ftrace_rec();
2491 struct ftrace_rec_iter {
2492 struct ftrace_page *pg;
2497 * ftrace_rec_iter_start, start up iterating over traced functions
2499 * Returns an iterator handle that is used to iterate over all
2500 * the records that represent address locations where functions
2503 * May return NULL if no records are available.
2505 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2508 * We only use a single iterator.
2509 * Protected by the ftrace_lock mutex.
2511 static struct ftrace_rec_iter ftrace_rec_iter;
2512 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2514 iter->pg = ftrace_pages_start;
2517 /* Could have empty pages */
2518 while (iter->pg && !iter->pg->index)
2519 iter->pg = iter->pg->next;
2528 * ftrace_rec_iter_next, get the next record to process.
2529 * @iter: The handle to the iterator.
2531 * Returns the next iterator after the given iterator @iter.
2533 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2537 if (iter->index >= iter->pg->index) {
2538 iter->pg = iter->pg->next;
2541 /* Could have empty pages */
2542 while (iter->pg && !iter->pg->index)
2543 iter->pg = iter->pg->next;
2553 * ftrace_rec_iter_record, get the record at the iterator location
2554 * @iter: The current iterator location
2556 * Returns the record that the current @iter is at.
2558 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2560 return &iter->pg->records[iter->index];
2564 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
2568 if (unlikely(ftrace_disabled))
2571 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
2573 ftrace_bug_type = FTRACE_BUG_INIT;
2574 ftrace_bug(ret, rec);
2581 * archs can override this function if they must do something
2582 * before the modifying code is performed.
2584 int __weak ftrace_arch_code_modify_prepare(void)
2590 * archs can override this function if they must do something
2591 * after the modifying code is performed.
2593 int __weak ftrace_arch_code_modify_post_process(void)
2598 void ftrace_modify_all_code(int command)
2600 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2604 * If the ftrace_caller calls a ftrace_ops func directly,
2605 * we need to make sure that it only traces functions it
2606 * expects to trace. When doing the switch of functions,
2607 * we need to update to the ftrace_ops_list_func first
2608 * before the transition between old and new calls are set,
2609 * as the ftrace_ops_list_func will check the ops hashes
2610 * to make sure the ops are having the right functions
2614 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2615 if (FTRACE_WARN_ON(err))
2619 if (command & FTRACE_UPDATE_CALLS)
2620 ftrace_replace_code(1);
2621 else if (command & FTRACE_DISABLE_CALLS)
2622 ftrace_replace_code(0);
2624 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2625 function_trace_op = set_function_trace_op;
2627 /* If irqs are disabled, we are in stop machine */
2628 if (!irqs_disabled())
2629 smp_call_function(ftrace_sync_ipi, NULL, 1);
2630 err = ftrace_update_ftrace_func(ftrace_trace_function);
2631 if (FTRACE_WARN_ON(err))
2635 if (command & FTRACE_START_FUNC_RET)
2636 err = ftrace_enable_ftrace_graph_caller();
2637 else if (command & FTRACE_STOP_FUNC_RET)
2638 err = ftrace_disable_ftrace_graph_caller();
2639 FTRACE_WARN_ON(err);
2642 static int __ftrace_modify_code(void *data)
2644 int *command = data;
2646 ftrace_modify_all_code(*command);
2652 * ftrace_run_stop_machine, go back to the stop machine method
2653 * @command: The command to tell ftrace what to do
2655 * If an arch needs to fall back to the stop machine method, the
2656 * it can call this function.
2658 void ftrace_run_stop_machine(int command)
2660 stop_machine(__ftrace_modify_code, &command, NULL);
2664 * arch_ftrace_update_code, modify the code to trace or not trace
2665 * @command: The command that needs to be done
2667 * Archs can override this function if it does not need to
2668 * run stop_machine() to modify code.
2670 void __weak arch_ftrace_update_code(int command)
2672 ftrace_run_stop_machine(command);
2675 static void ftrace_run_update_code(int command)
2679 ret = ftrace_arch_code_modify_prepare();
2680 FTRACE_WARN_ON(ret);
2685 * By default we use stop_machine() to modify the code.
2686 * But archs can do what ever they want as long as it
2687 * is safe. The stop_machine() is the safest, but also
2688 * produces the most overhead.
2690 arch_ftrace_update_code(command);
2692 ret = ftrace_arch_code_modify_post_process();
2693 FTRACE_WARN_ON(ret);
2696 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2697 struct ftrace_ops_hash *old_hash)
2699 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2700 ops->old_hash.filter_hash = old_hash->filter_hash;
2701 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2702 ftrace_run_update_code(command);
2703 ops->old_hash.filter_hash = NULL;
2704 ops->old_hash.notrace_hash = NULL;
2705 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2708 static ftrace_func_t saved_ftrace_func;
2709 static int ftrace_start_up;
2711 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2715 static void per_cpu_ops_free(struct ftrace_ops *ops)
2717 free_percpu(ops->disabled);
2720 static void ftrace_startup_enable(int command)
2722 if (saved_ftrace_func != ftrace_trace_function) {
2723 saved_ftrace_func = ftrace_trace_function;
2724 command |= FTRACE_UPDATE_TRACE_FUNC;
2727 if (!command || !ftrace_enabled)
2730 ftrace_run_update_code(command);
2733 static void ftrace_startup_all(int command)
2735 update_all_ops = true;
2736 ftrace_startup_enable(command);
2737 update_all_ops = false;
2740 static int ftrace_startup(struct ftrace_ops *ops, int command)
2744 if (unlikely(ftrace_disabled))
2747 ret = __register_ftrace_function(ops);
2754 * Note that ftrace probes uses this to start up
2755 * and modify functions it will probe. But we still
2756 * set the ADDING flag for modification, as probes
2757 * do not have trampolines. If they add them in the
2758 * future, then the probes will need to distinguish
2759 * between adding and updating probes.
2761 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2763 ret = ftrace_hash_ipmodify_enable(ops);
2765 /* Rollback registration process */
2766 __unregister_ftrace_function(ops);
2768 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2772 if (ftrace_hash_rec_enable(ops, 1))
2773 command |= FTRACE_UPDATE_CALLS;
2775 ftrace_startup_enable(command);
2777 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2782 static int ftrace_shutdown(struct ftrace_ops *ops, int command)
2786 if (unlikely(ftrace_disabled))
2789 ret = __unregister_ftrace_function(ops);
2795 * Just warn in case of unbalance, no need to kill ftrace, it's not
2796 * critical but the ftrace_call callers may be never nopped again after
2797 * further ftrace uses.
2799 WARN_ON_ONCE(ftrace_start_up < 0);
2801 /* Disabling ipmodify never fails */
2802 ftrace_hash_ipmodify_disable(ops);
2804 if (ftrace_hash_rec_disable(ops, 1))
2805 command |= FTRACE_UPDATE_CALLS;
2807 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2809 if (saved_ftrace_func != ftrace_trace_function) {
2810 saved_ftrace_func = ftrace_trace_function;
2811 command |= FTRACE_UPDATE_TRACE_FUNC;
2814 if (!command || !ftrace_enabled) {
2816 * If these are per_cpu ops, they still need their
2817 * per_cpu field freed. Since, function tracing is
2818 * not currently active, we can just free them
2819 * without synchronizing all CPUs.
2821 if (ops->flags & FTRACE_OPS_FL_PER_CPU)
2822 per_cpu_ops_free(ops);
2827 * If the ops uses a trampoline, then it needs to be
2828 * tested first on update.
2830 ops->flags |= FTRACE_OPS_FL_REMOVING;
2833 /* The trampoline logic checks the old hashes */
2834 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2835 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2837 ftrace_run_update_code(command);
2840 * If there's no more ops registered with ftrace, run a
2841 * sanity check to make sure all rec flags are cleared.
2843 if (ftrace_ops_list == &ftrace_list_end) {
2844 struct ftrace_page *pg;
2845 struct dyn_ftrace *rec;
2847 do_for_each_ftrace_rec(pg, rec) {
2848 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
2849 pr_warn(" %pS flags:%lx\n",
2850 (void *)rec->ip, rec->flags);
2851 } while_for_each_ftrace_rec();
2854 ops->old_hash.filter_hash = NULL;
2855 ops->old_hash.notrace_hash = NULL;
2858 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2861 * Dynamic ops may be freed, we must make sure that all
2862 * callers are done before leaving this function.
2863 * The same goes for freeing the per_cpu data of the per_cpu
2866 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU)) {
2868 * We need to do a hard force of sched synchronization.
2869 * This is because we use preempt_disable() to do RCU, but
2870 * the function tracers can be called where RCU is not watching
2871 * (like before user_exit()). We can not rely on the RCU
2872 * infrastructure to do the synchronization, thus we must do it
2875 schedule_on_each_cpu(ftrace_sync);
2878 * When the kernel is preeptive, tasks can be preempted
2879 * while on a ftrace trampoline. Just scheduling a task on
2880 * a CPU is not good enough to flush them. Calling
2881 * synchornize_rcu_tasks() will wait for those tasks to
2882 * execute and either schedule voluntarily or enter user space.
2884 if (IS_ENABLED(CONFIG_PREEMPT))
2885 synchronize_rcu_tasks();
2887 arch_ftrace_trampoline_free(ops);
2889 if (ops->flags & FTRACE_OPS_FL_PER_CPU)
2890 per_cpu_ops_free(ops);
2896 static void ftrace_startup_sysctl(void)
2900 if (unlikely(ftrace_disabled))
2903 /* Force update next time */
2904 saved_ftrace_func = NULL;
2905 /* ftrace_start_up is true if we want ftrace running */
2906 if (ftrace_start_up) {
2907 command = FTRACE_UPDATE_CALLS;
2908 if (ftrace_graph_active)
2909 command |= FTRACE_START_FUNC_RET;
2910 ftrace_startup_enable(command);
2914 static void ftrace_shutdown_sysctl(void)
2918 if (unlikely(ftrace_disabled))
2921 /* ftrace_start_up is true if ftrace is running */
2922 if (ftrace_start_up) {
2923 command = FTRACE_DISABLE_CALLS;
2924 if (ftrace_graph_active)
2925 command |= FTRACE_STOP_FUNC_RET;
2926 ftrace_run_update_code(command);
2930 static u64 ftrace_update_time;
2931 unsigned long ftrace_update_tot_cnt;
2933 static inline int ops_traces_mod(struct ftrace_ops *ops)
2936 * Filter_hash being empty will default to trace module.
2937 * But notrace hash requires a test of individual module functions.
2939 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
2940 ftrace_hash_empty(ops->func_hash->notrace_hash);
2944 * Check if the current ops references the record.
2946 * If the ops traces all functions, then it was already accounted for.
2947 * If the ops does not trace the current record function, skip it.
2948 * If the ops ignores the function via notrace filter, skip it.
2951 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2953 /* If ops isn't enabled, ignore it */
2954 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2957 /* If ops traces all then it includes this function */
2958 if (ops_traces_mod(ops))
2961 /* The function must be in the filter */
2962 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
2963 !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
2966 /* If in notrace hash, we ignore it too */
2967 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
2973 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
2975 struct ftrace_page *pg;
2976 struct dyn_ftrace *p;
2978 unsigned long update_cnt = 0;
2979 unsigned long rec_flags = 0;
2982 start = ftrace_now(raw_smp_processor_id());
2985 * When a module is loaded, this function is called to convert
2986 * the calls to mcount in its text to nops, and also to create
2987 * an entry in the ftrace data. Now, if ftrace is activated
2988 * after this call, but before the module sets its text to
2989 * read-only, the modification of enabling ftrace can fail if
2990 * the read-only is done while ftrace is converting the calls.
2991 * To prevent this, the module's records are set as disabled
2992 * and will be enabled after the call to set the module's text
2996 rec_flags |= FTRACE_FL_DISABLED;
2998 for (pg = new_pgs; pg; pg = pg->next) {
3000 for (i = 0; i < pg->index; i++) {
3002 /* If something went wrong, bail without enabling anything */
3003 if (unlikely(ftrace_disabled))
3006 p = &pg->records[i];
3007 p->flags = rec_flags;
3010 * Do the initial record conversion from mcount jump
3011 * to the NOP instructions.
3013 if (!ftrace_code_disable(mod, p))
3020 stop = ftrace_now(raw_smp_processor_id());
3021 ftrace_update_time = stop - start;
3022 ftrace_update_tot_cnt += update_cnt;
3027 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3032 if (WARN_ON(!count))
3035 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
3038 * We want to fill as much as possible. No more than a page
3041 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
3045 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3048 /* if we can't allocate this size, try something smaller */
3055 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3064 static struct ftrace_page *
3065 ftrace_allocate_pages(unsigned long num_to_init)
3067 struct ftrace_page *start_pg;
3068 struct ftrace_page *pg;
3075 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3080 * Try to allocate as much as possible in one continues
3081 * location that fills in all of the space. We want to
3082 * waste as little space as possible.
3085 cnt = ftrace_allocate_records(pg, num_to_init);
3093 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3105 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3106 free_pages((unsigned long)pg->records, order);
3107 start_pg = pg->next;
3111 pr_info("ftrace: FAILED to allocate memory for functions\n");
3115 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3117 struct ftrace_iterator {
3121 struct ftrace_page *pg;
3122 struct dyn_ftrace *func;
3123 struct ftrace_func_probe *probe;
3124 struct ftrace_func_entry *probe_entry;
3125 struct trace_parser parser;
3126 struct ftrace_hash *hash;
3127 struct ftrace_ops *ops;
3128 struct trace_array *tr;
3129 struct list_head *mod_list;
3136 t_probe_next(struct seq_file *m, loff_t *pos)
3138 struct ftrace_iterator *iter = m->private;
3139 struct trace_array *tr = iter->ops->private;
3140 struct list_head *func_probes;
3141 struct ftrace_hash *hash;
3142 struct list_head *next;
3143 struct hlist_node *hnd = NULL;
3144 struct hlist_head *hhd;
3153 func_probes = &tr->func_probes;
3154 if (list_empty(func_probes))
3158 next = func_probes->next;
3159 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3162 if (iter->probe_entry)
3163 hnd = &iter->probe_entry->hlist;
3165 hash = iter->probe->ops.func_hash->filter_hash;
3166 size = 1 << hash->size_bits;
3169 if (iter->pidx >= size) {
3170 if (iter->probe->list.next == func_probes)
3172 next = iter->probe->list.next;
3173 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3174 hash = iter->probe->ops.func_hash->filter_hash;
3175 size = 1 << hash->size_bits;
3179 hhd = &hash->buckets[iter->pidx];
3181 if (hlist_empty(hhd)) {
3197 if (WARN_ON_ONCE(!hnd))
3200 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3205 static void *t_probe_start(struct seq_file *m, loff_t *pos)
3207 struct ftrace_iterator *iter = m->private;
3211 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3214 if (iter->mod_pos > *pos)
3218 iter->probe_entry = NULL;
3220 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3221 p = t_probe_next(m, &l);
3228 /* Only set this if we have an item */
3229 iter->flags |= FTRACE_ITER_PROBE;
3235 t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3237 struct ftrace_func_entry *probe_entry;
3238 struct ftrace_probe_ops *probe_ops;
3239 struct ftrace_func_probe *probe;
3241 probe = iter->probe;
3242 probe_entry = iter->probe_entry;
3244 if (WARN_ON_ONCE(!probe || !probe_entry))
3247 probe_ops = probe->probe_ops;
3249 if (probe_ops->print)
3250 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3252 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3253 (void *)probe_ops->func);
3259 t_mod_next(struct seq_file *m, loff_t *pos)
3261 struct ftrace_iterator *iter = m->private;
3262 struct trace_array *tr = iter->tr;
3267 iter->mod_list = iter->mod_list->next;
3269 if (iter->mod_list == &tr->mod_trace ||
3270 iter->mod_list == &tr->mod_notrace) {
3271 iter->flags &= ~FTRACE_ITER_MOD;
3275 iter->mod_pos = *pos;
3280 static void *t_mod_start(struct seq_file *m, loff_t *pos)
3282 struct ftrace_iterator *iter = m->private;
3286 if (iter->func_pos > *pos)
3289 iter->mod_pos = iter->func_pos;
3291 /* probes are only available if tr is set */
3295 for (l = 0; l <= (*pos - iter->func_pos); ) {
3296 p = t_mod_next(m, &l);
3301 iter->flags &= ~FTRACE_ITER_MOD;
3302 return t_probe_start(m, pos);
3305 /* Only set this if we have an item */
3306 iter->flags |= FTRACE_ITER_MOD;
3312 t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3314 struct ftrace_mod_load *ftrace_mod;
3315 struct trace_array *tr = iter->tr;
3317 if (WARN_ON_ONCE(!iter->mod_list) ||
3318 iter->mod_list == &tr->mod_trace ||
3319 iter->mod_list == &tr->mod_notrace)
3322 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3324 if (ftrace_mod->func)
3325 seq_printf(m, "%s", ftrace_mod->func);
3329 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3335 t_func_next(struct seq_file *m, loff_t *pos)
3337 struct ftrace_iterator *iter = m->private;
3338 struct dyn_ftrace *rec = NULL;
3343 if (iter->idx >= iter->pg->index) {
3344 if (iter->pg->next) {
3345 iter->pg = iter->pg->next;
3350 rec = &iter->pg->records[iter->idx++];
3351 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3352 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3354 ((iter->flags & FTRACE_ITER_ENABLED) &&
3355 !(rec->flags & FTRACE_FL_ENABLED))) {
3365 iter->pos = iter->func_pos = *pos;
3372 t_next(struct seq_file *m, void *v, loff_t *pos)
3374 struct ftrace_iterator *iter = m->private;
3375 loff_t l = *pos; /* t_probe_start() must use original pos */
3378 if (unlikely(ftrace_disabled))
3381 if (iter->flags & FTRACE_ITER_PROBE)
3382 return t_probe_next(m, pos);
3384 if (iter->flags & FTRACE_ITER_MOD)
3385 return t_mod_next(m, pos);
3387 if (iter->flags & FTRACE_ITER_PRINTALL) {
3388 /* next must increment pos, and t_probe_start does not */
3390 return t_mod_start(m, &l);
3393 ret = t_func_next(m, pos);
3396 return t_mod_start(m, &l);
3401 static void reset_iter_read(struct ftrace_iterator *iter)
3405 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3408 static void *t_start(struct seq_file *m, loff_t *pos)
3410 struct ftrace_iterator *iter = m->private;
3414 mutex_lock(&ftrace_lock);
3416 if (unlikely(ftrace_disabled))
3420 * If an lseek was done, then reset and start from beginning.
3422 if (*pos < iter->pos)
3423 reset_iter_read(iter);
3426 * For set_ftrace_filter reading, if we have the filter
3427 * off, we can short cut and just print out that all
3428 * functions are enabled.
3430 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3431 ftrace_hash_empty(iter->hash)) {
3432 iter->func_pos = 1; /* Account for the message */
3434 return t_mod_start(m, pos);
3435 iter->flags |= FTRACE_ITER_PRINTALL;
3436 /* reset in case of seek/pread */
3437 iter->flags &= ~FTRACE_ITER_PROBE;
3441 if (iter->flags & FTRACE_ITER_MOD)
3442 return t_mod_start(m, pos);
3445 * Unfortunately, we need to restart at ftrace_pages_start
3446 * every time we let go of the ftrace_mutex. This is because
3447 * those pointers can change without the lock.
3449 iter->pg = ftrace_pages_start;
3451 for (l = 0; l <= *pos; ) {
3452 p = t_func_next(m, &l);
3458 return t_mod_start(m, pos);
3463 static void t_stop(struct seq_file *m, void *p)
3465 mutex_unlock(&ftrace_lock);
3469 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3474 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3475 struct dyn_ftrace *rec)
3479 ptr = arch_ftrace_trampoline_func(ops, rec);
3481 seq_printf(m, " ->%pS", ptr);
3484 static int t_show(struct seq_file *m, void *v)
3486 struct ftrace_iterator *iter = m->private;
3487 struct dyn_ftrace *rec;
3489 if (iter->flags & FTRACE_ITER_PROBE)
3490 return t_probe_show(m, iter);
3492 if (iter->flags & FTRACE_ITER_MOD)
3493 return t_mod_show(m, iter);
3495 if (iter->flags & FTRACE_ITER_PRINTALL) {
3496 if (iter->flags & FTRACE_ITER_NOTRACE)
3497 seq_puts(m, "#### no functions disabled ####\n");
3499 seq_puts(m, "#### all functions enabled ####\n");
3508 seq_printf(m, "%ps", (void *)rec->ip);
3509 if (iter->flags & FTRACE_ITER_ENABLED) {
3510 struct ftrace_ops *ops;
3512 seq_printf(m, " (%ld)%s%s",
3513 ftrace_rec_count(rec),
3514 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3515 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ");
3516 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3517 ops = ftrace_find_tramp_ops_any(rec);
3520 seq_printf(m, "\ttramp: %pS (%pS)",
3521 (void *)ops->trampoline,
3523 add_trampoline_func(m, ops, rec);
3524 ops = ftrace_find_tramp_ops_next(rec, ops);
3527 seq_puts(m, "\ttramp: ERROR!");
3529 add_trampoline_func(m, NULL, rec);
3538 static const struct seq_operations show_ftrace_seq_ops = {
3546 ftrace_avail_open(struct inode *inode, struct file *file)
3548 struct ftrace_iterator *iter;
3550 if (unlikely(ftrace_disabled))
3553 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3557 iter->pg = ftrace_pages_start;
3558 iter->ops = &global_ops;
3564 ftrace_enabled_open(struct inode *inode, struct file *file)
3566 struct ftrace_iterator *iter;
3568 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3572 iter->pg = ftrace_pages_start;
3573 iter->flags = FTRACE_ITER_ENABLED;
3574 iter->ops = &global_ops;
3580 * ftrace_regex_open - initialize function tracer filter files
3581 * @ops: The ftrace_ops that hold the hash filters
3582 * @flag: The type of filter to process
3583 * @inode: The inode, usually passed in to your open routine
3584 * @file: The file, usually passed in to your open routine
3586 * ftrace_regex_open() initializes the filter files for the
3587 * @ops. Depending on @flag it may process the filter hash or
3588 * the notrace hash of @ops. With this called from the open
3589 * routine, you can use ftrace_filter_write() for the write
3590 * routine if @flag has FTRACE_ITER_FILTER set, or
3591 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3592 * tracing_lseek() should be used as the lseek routine, and
3593 * release must call ftrace_regex_release().
3596 ftrace_regex_open(struct ftrace_ops *ops, int flag,
3597 struct inode *inode, struct file *file)
3599 struct ftrace_iterator *iter;
3600 struct ftrace_hash *hash;
3601 struct list_head *mod_head;
3602 struct trace_array *tr = ops->private;
3605 ftrace_ops_init(ops);
3607 if (unlikely(ftrace_disabled))
3610 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3614 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
3623 mutex_lock(&ops->func_hash->regex_lock);
3625 if (flag & FTRACE_ITER_NOTRACE) {
3626 hash = ops->func_hash->notrace_hash;
3627 mod_head = tr ? &tr->mod_notrace : NULL;
3629 hash = ops->func_hash->filter_hash;
3630 mod_head = tr ? &tr->mod_trace : NULL;
3633 iter->mod_list = mod_head;
3635 if (file->f_mode & FMODE_WRITE) {
3636 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3638 if (file->f_flags & O_TRUNC) {
3639 iter->hash = alloc_ftrace_hash(size_bits);
3640 clear_ftrace_mod_list(mod_head);
3642 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3646 trace_parser_put(&iter->parser);
3654 if (file->f_mode & FMODE_READ) {
3655 iter->pg = ftrace_pages_start;
3657 ret = seq_open(file, &show_ftrace_seq_ops);
3659 struct seq_file *m = file->private_data;
3663 free_ftrace_hash(iter->hash);
3664 trace_parser_put(&iter->parser);
3668 file->private_data = iter;
3671 mutex_unlock(&ops->func_hash->regex_lock);
3677 ftrace_filter_open(struct inode *inode, struct file *file)
3679 struct ftrace_ops *ops = inode->i_private;
3681 return ftrace_regex_open(ops,
3682 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3687 ftrace_notrace_open(struct inode *inode, struct file *file)
3689 struct ftrace_ops *ops = inode->i_private;
3691 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3695 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3696 struct ftrace_glob {
3703 * If symbols in an architecture don't correspond exactly to the user-visible
3704 * name of what they represent, it is possible to define this function to
3705 * perform the necessary adjustments.
3707 char * __weak arch_ftrace_match_adjust(char *str, const char *search)
3712 static int ftrace_match(char *str, struct ftrace_glob *g)
3717 str = arch_ftrace_match_adjust(str, g->search);
3721 if (strcmp(str, g->search) == 0)
3724 case MATCH_FRONT_ONLY:
3725 if (strncmp(str, g->search, g->len) == 0)
3728 case MATCH_MIDDLE_ONLY:
3729 if (strstr(str, g->search))
3732 case MATCH_END_ONLY:
3734 if (slen >= g->len &&
3735 memcmp(str + slen - g->len, g->search, g->len) == 0)
3739 if (glob_match(g->search, str))
3748 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3750 struct ftrace_func_entry *entry;
3753 entry = ftrace_lookup_ip(hash, rec->ip);
3755 /* Do nothing if it doesn't exist */
3759 free_hash_entry(hash, entry);
3761 /* Do nothing if it exists */
3765 ret = add_hash_entry(hash, rec->ip);
3771 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3772 struct ftrace_glob *mod_g, int exclude_mod)
3774 char str[KSYM_SYMBOL_LEN];
3777 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3780 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3782 /* blank module name to match all modules */
3784 /* blank module globbing: modname xor exclude_mod */
3785 if (!exclude_mod != !modname)
3791 * exclude_mod is set to trace everything but the given
3792 * module. If it is set and the module matches, then
3793 * return 0. If it is not set, and the module doesn't match
3794 * also return 0. Otherwise, check the function to see if
3797 if (!mod_matches == !exclude_mod)
3800 /* blank search means to match all funcs in the mod */
3805 return ftrace_match(str, func_g);
3809 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
3811 struct ftrace_page *pg;
3812 struct dyn_ftrace *rec;
3813 struct ftrace_glob func_g = { .type = MATCH_FULL };
3814 struct ftrace_glob mod_g = { .type = MATCH_FULL };
3815 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
3816 int exclude_mod = 0;
3819 int clear_filter = 0;
3822 func_g.type = filter_parse_regex(func, len, &func_g.search,
3824 func_g.len = strlen(func_g.search);
3828 mod_g.type = filter_parse_regex(mod, strlen(mod),
3829 &mod_g.search, &exclude_mod);
3830 mod_g.len = strlen(mod_g.search);
3833 mutex_lock(&ftrace_lock);
3835 if (unlikely(ftrace_disabled))
3838 do_for_each_ftrace_rec(pg, rec) {
3840 if (rec->flags & FTRACE_FL_DISABLED)
3843 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
3844 ret = enter_record(hash, rec, clear_filter);
3851 } while_for_each_ftrace_rec();
3853 mutex_unlock(&ftrace_lock);
3859 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
3861 return match_records(hash, buff, len, NULL);
3864 static void ftrace_ops_update_code(struct ftrace_ops *ops,
3865 struct ftrace_ops_hash *old_hash)
3867 struct ftrace_ops *op;
3869 if (!ftrace_enabled)
3872 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
3873 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
3878 * If this is the shared global_ops filter, then we need to
3879 * check if there is another ops that shares it, is enabled.
3880 * If so, we still need to run the modify code.
3882 if (ops->func_hash != &global_ops.local_hash)
3885 do_for_each_ftrace_op(op, ftrace_ops_list) {
3886 if (op->func_hash == &global_ops.local_hash &&
3887 op->flags & FTRACE_OPS_FL_ENABLED) {
3888 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
3889 /* Only need to do this once */
3892 } while_for_each_ftrace_op(op);
3895 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
3896 struct ftrace_hash **orig_hash,
3897 struct ftrace_hash *hash,
3900 struct ftrace_ops_hash old_hash_ops;
3901 struct ftrace_hash *old_hash;
3904 old_hash = *orig_hash;
3905 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
3906 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
3907 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3909 ftrace_ops_update_code(ops, &old_hash_ops);
3910 free_ftrace_hash_rcu(old_hash);
3915 static bool module_exists(const char *module)
3917 /* All modules have the symbol __this_module */
3918 const char this_mod[] = "__this_module";
3919 const int modname_size = MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 1;
3920 char modname[modname_size + 1];
3924 n = snprintf(modname, modname_size + 1, "%s:%s", module, this_mod);
3926 if (n > modname_size)
3929 val = module_kallsyms_lookup_name(modname);
3933 static int cache_mod(struct trace_array *tr,
3934 const char *func, char *module, int enable)
3936 struct ftrace_mod_load *ftrace_mod, *n;
3937 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
3940 mutex_lock(&ftrace_lock);
3942 /* We do not cache inverse filters */
3943 if (func[0] == '!') {
3947 /* Look to remove this hash */
3948 list_for_each_entry_safe(ftrace_mod, n, head, list) {
3949 if (strcmp(ftrace_mod->module, module) != 0)
3952 /* no func matches all */
3953 if (strcmp(func, "*") == 0 ||
3954 (ftrace_mod->func &&
3955 strcmp(ftrace_mod->func, func) == 0)) {
3957 free_ftrace_mod(ftrace_mod);
3965 /* We only care about modules that have not been loaded yet */
3966 if (module_exists(module))
3969 /* Save this string off, and execute it when the module is loaded */
3970 ret = ftrace_add_mod(tr, func, module, enable);
3972 mutex_unlock(&ftrace_lock);
3978 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
3979 int reset, int enable);
3981 #ifdef CONFIG_MODULES
3982 static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
3983 char *mod, bool enable)
3985 struct ftrace_mod_load *ftrace_mod, *n;
3986 struct ftrace_hash **orig_hash, *new_hash;
3987 LIST_HEAD(process_mods);
3991 mutex_lock(&ops->func_hash->regex_lock);
3994 orig_hash = &ops->func_hash->filter_hash;
3996 orig_hash = &ops->func_hash->notrace_hash;
3998 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4001 goto out; /* warn? */
4003 mutex_lock(&ftrace_lock);
4005 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4007 if (strcmp(ftrace_mod->module, mod) != 0)
4010 if (ftrace_mod->func)
4011 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4013 func = kstrdup("*", GFP_KERNEL);
4015 if (!func) /* warn? */
4018 list_del(&ftrace_mod->list);
4019 list_add(&ftrace_mod->list, &process_mods);
4021 /* Use the newly allocated func, as it may be "*" */
4022 kfree(ftrace_mod->func);
4023 ftrace_mod->func = func;
4026 mutex_unlock(&ftrace_lock);
4028 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4030 func = ftrace_mod->func;
4032 /* Grabs ftrace_lock, which is why we have this extra step */
4033 match_records(new_hash, func, strlen(func), mod);
4034 free_ftrace_mod(ftrace_mod);
4037 if (enable && list_empty(head))
4038 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4040 mutex_lock(&ftrace_lock);
4042 ret = ftrace_hash_move_and_update_ops(ops, orig_hash,
4044 mutex_unlock(&ftrace_lock);
4047 mutex_unlock(&ops->func_hash->regex_lock);
4049 free_ftrace_hash(new_hash);
4052 static void process_cached_mods(const char *mod_name)
4054 struct trace_array *tr;
4057 mod = kstrdup(mod_name, GFP_KERNEL);
4061 mutex_lock(&trace_types_lock);
4062 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4063 if (!list_empty(&tr->mod_trace))
4064 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4065 if (!list_empty(&tr->mod_notrace))
4066 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4068 mutex_unlock(&trace_types_lock);
4075 * We register the module command as a template to show others how
4076 * to register the a command as well.
4080 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4081 char *func_orig, char *cmd, char *module, int enable)
4086 /* match_records() modifies func, and we need the original */
4087 func = kstrdup(func_orig, GFP_KERNEL);
4092 * cmd == 'mod' because we only registered this func
4093 * for the 'mod' ftrace_func_command.
4094 * But if you register one func with multiple commands,
4095 * you can tell which command was used by the cmd
4098 ret = match_records(hash, func, strlen(func), module);
4102 return cache_mod(tr, func_orig, module, enable);
4108 static struct ftrace_func_command ftrace_mod_cmd = {
4110 .func = ftrace_mod_callback,
4113 static int __init ftrace_mod_cmd_init(void)
4115 return register_ftrace_command(&ftrace_mod_cmd);
4117 core_initcall(ftrace_mod_cmd_init);
4119 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4120 struct ftrace_ops *op, struct pt_regs *pt_regs)
4122 struct ftrace_probe_ops *probe_ops;
4123 struct ftrace_func_probe *probe;
4125 probe = container_of(op, struct ftrace_func_probe, ops);
4126 probe_ops = probe->probe_ops;
4129 * Disable preemption for these calls to prevent a RCU grace
4130 * period. This syncs the hash iteration and freeing of items
4131 * on the hash. rcu_read_lock is too dangerous here.
4133 preempt_disable_notrace();
4134 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4135 preempt_enable_notrace();
4138 struct ftrace_func_map {
4139 struct ftrace_func_entry entry;
4143 struct ftrace_func_mapper {
4144 struct ftrace_hash hash;
4148 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4150 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4152 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4154 struct ftrace_hash *hash;
4157 * The mapper is simply a ftrace_hash, but since the entries
4158 * in the hash are not ftrace_func_entry type, we define it
4159 * as a separate structure.
4161 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4162 return (struct ftrace_func_mapper *)hash;
4166 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4167 * @mapper: The mapper that has the ip maps
4168 * @ip: the instruction pointer to find the data for
4170 * Returns the data mapped to @ip if found otherwise NULL. The return
4171 * is actually the address of the mapper data pointer. The address is
4172 * returned for use cases where the data is no bigger than a long, and
4173 * the user can use the data pointer as its data instead of having to
4174 * allocate more memory for the reference.
4176 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4179 struct ftrace_func_entry *entry;
4180 struct ftrace_func_map *map;
4182 entry = ftrace_lookup_ip(&mapper->hash, ip);
4186 map = (struct ftrace_func_map *)entry;
4191 * ftrace_func_mapper_add_ip - Map some data to an ip
4192 * @mapper: The mapper that has the ip maps
4193 * @ip: The instruction pointer address to map @data to
4194 * @data: The data to map to @ip
4196 * Returns 0 on succes otherwise an error.
4198 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4199 unsigned long ip, void *data)
4201 struct ftrace_func_entry *entry;
4202 struct ftrace_func_map *map;
4204 entry = ftrace_lookup_ip(&mapper->hash, ip);
4208 map = kmalloc(sizeof(*map), GFP_KERNEL);
4215 __add_hash_entry(&mapper->hash, &map->entry);
4221 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4222 * @mapper: The mapper that has the ip maps
4223 * @ip: The instruction pointer address to remove the data from
4225 * Returns the data if it is found, otherwise NULL.
4226 * Note, if the data pointer is used as the data itself, (see
4227 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4228 * if the data pointer was set to zero.
4230 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4233 struct ftrace_func_entry *entry;
4234 struct ftrace_func_map *map;
4237 entry = ftrace_lookup_ip(&mapper->hash, ip);
4241 map = (struct ftrace_func_map *)entry;
4244 remove_hash_entry(&mapper->hash, entry);
4251 * free_ftrace_func_mapper - free a mapping of ips and data
4252 * @mapper: The mapper that has the ip maps
4253 * @free_func: A function to be called on each data item.
4255 * This is used to free the function mapper. The @free_func is optional
4256 * and can be used if the data needs to be freed as well.
4258 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4259 ftrace_mapper_func free_func)
4261 struct ftrace_func_entry *entry;
4262 struct ftrace_func_map *map;
4263 struct hlist_head *hhd;
4264 int size = 1 << mapper->hash.size_bits;
4267 if (free_func && mapper->hash.count) {
4268 for (i = 0; i < size; i++) {
4269 hhd = &mapper->hash.buckets[i];
4270 hlist_for_each_entry(entry, hhd, hlist) {
4271 map = (struct ftrace_func_map *)entry;
4276 free_ftrace_hash(&mapper->hash);
4279 static void release_probe(struct ftrace_func_probe *probe)
4281 struct ftrace_probe_ops *probe_ops;
4283 mutex_lock(&ftrace_lock);
4285 WARN_ON(probe->ref <= 0);
4287 /* Subtract the ref that was used to protect this instance */
4291 probe_ops = probe->probe_ops;
4293 * Sending zero as ip tells probe_ops to free
4294 * the probe->data itself
4296 if (probe_ops->free)
4297 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4298 list_del(&probe->list);
4301 mutex_unlock(&ftrace_lock);
4304 static void acquire_probe_locked(struct ftrace_func_probe *probe)
4307 * Add one ref to keep it from being freed when releasing the
4308 * ftrace_lock mutex.
4314 register_ftrace_function_probe(char *glob, struct trace_array *tr,
4315 struct ftrace_probe_ops *probe_ops,
4318 struct ftrace_func_entry *entry;
4319 struct ftrace_func_probe *probe;
4320 struct ftrace_hash **orig_hash;
4321 struct ftrace_hash *old_hash;
4322 struct ftrace_hash *hash;
4331 /* We do not support '!' for function probes */
4332 if (WARN_ON(glob[0] == '!'))
4336 mutex_lock(&ftrace_lock);
4337 /* Check if the probe_ops is already registered */
4338 list_for_each_entry(probe, &tr->func_probes, list) {
4339 if (probe->probe_ops == probe_ops)
4342 if (&probe->list == &tr->func_probes) {
4343 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4345 mutex_unlock(&ftrace_lock);
4348 probe->probe_ops = probe_ops;
4349 probe->ops.func = function_trace_probe_call;
4351 ftrace_ops_init(&probe->ops);
4352 list_add(&probe->list, &tr->func_probes);
4355 acquire_probe_locked(probe);
4357 mutex_unlock(&ftrace_lock);
4359 mutex_lock(&probe->ops.func_hash->regex_lock);
4361 orig_hash = &probe->ops.func_hash->filter_hash;
4362 old_hash = *orig_hash;
4363 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4365 ret = ftrace_match_records(hash, glob, strlen(glob));
4367 /* Nothing found? */
4374 size = 1 << hash->size_bits;
4375 for (i = 0; i < size; i++) {
4376 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4377 if (ftrace_lookup_ip(old_hash, entry->ip))
4380 * The caller might want to do something special
4381 * for each function we find. We call the callback
4382 * to give the caller an opportunity to do so.
4384 if (probe_ops->init) {
4385 ret = probe_ops->init(probe_ops, tr,
4389 if (probe_ops->free && count)
4390 probe_ops->free(probe_ops, tr,
4400 mutex_lock(&ftrace_lock);
4403 /* Nothing was added? */
4408 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4413 /* One ref for each new function traced */
4414 probe->ref += count;
4416 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4417 ret = ftrace_startup(&probe->ops, 0);
4420 mutex_unlock(&ftrace_lock);
4425 mutex_unlock(&probe->ops.func_hash->regex_lock);
4426 free_ftrace_hash(hash);
4428 release_probe(probe);
4433 if (!probe_ops->free || !count)
4436 /* Failed to do the move, need to call the free functions */
4437 for (i = 0; i < size; i++) {
4438 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4439 if (ftrace_lookup_ip(old_hash, entry->ip))
4441 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4448 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4449 struct ftrace_probe_ops *probe_ops)
4451 struct ftrace_ops_hash old_hash_ops;
4452 struct ftrace_func_entry *entry;
4453 struct ftrace_func_probe *probe;
4454 struct ftrace_glob func_g;
4455 struct ftrace_hash **orig_hash;
4456 struct ftrace_hash *old_hash;
4457 struct ftrace_hash *hash = NULL;
4458 struct hlist_node *tmp;
4459 struct hlist_head hhd;
4460 char str[KSYM_SYMBOL_LEN];
4462 int i, ret = -ENODEV;
4465 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4466 func_g.search = NULL;
4470 func_g.type = filter_parse_regex(glob, strlen(glob),
4471 &func_g.search, ¬);
4472 func_g.len = strlen(func_g.search);
4473 func_g.search = glob;
4475 /* we do not support '!' for function probes */
4480 mutex_lock(&ftrace_lock);
4481 /* Check if the probe_ops is already registered */
4482 list_for_each_entry(probe, &tr->func_probes, list) {
4483 if (probe->probe_ops == probe_ops)
4486 if (&probe->list == &tr->func_probes)
4487 goto err_unlock_ftrace;
4490 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4491 goto err_unlock_ftrace;
4493 acquire_probe_locked(probe);
4495 mutex_unlock(&ftrace_lock);
4497 mutex_lock(&probe->ops.func_hash->regex_lock);
4499 orig_hash = &probe->ops.func_hash->filter_hash;
4500 old_hash = *orig_hash;
4502 if (ftrace_hash_empty(old_hash))
4505 old_hash_ops.filter_hash = old_hash;
4506 /* Probes only have filters */
4507 old_hash_ops.notrace_hash = NULL;
4510 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4514 INIT_HLIST_HEAD(&hhd);
4516 size = 1 << hash->size_bits;
4517 for (i = 0; i < size; i++) {
4518 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4520 if (func_g.search) {
4521 kallsyms_lookup(entry->ip, NULL, NULL,
4523 if (!ftrace_match(str, &func_g))
4527 remove_hash_entry(hash, entry);
4528 hlist_add_head(&entry->hlist, &hhd);
4532 /* Nothing found? */
4538 mutex_lock(&ftrace_lock);
4540 WARN_ON(probe->ref < count);
4542 probe->ref -= count;
4544 if (ftrace_hash_empty(hash))
4545 ftrace_shutdown(&probe->ops, 0);
4547 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4550 /* still need to update the function call sites */
4551 if (ftrace_enabled && !ftrace_hash_empty(hash))
4552 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4554 synchronize_sched();
4556 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4557 hlist_del(&entry->hlist);
4558 if (probe_ops->free)
4559 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4562 mutex_unlock(&ftrace_lock);
4565 mutex_unlock(&probe->ops.func_hash->regex_lock);
4566 free_ftrace_hash(hash);
4568 release_probe(probe);
4573 mutex_unlock(&ftrace_lock);
4577 void clear_ftrace_function_probes(struct trace_array *tr)
4579 struct ftrace_func_probe *probe, *n;
4581 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4582 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
4585 static LIST_HEAD(ftrace_commands);
4586 static DEFINE_MUTEX(ftrace_cmd_mutex);
4589 * Currently we only register ftrace commands from __init, so mark this
4592 __init int register_ftrace_command(struct ftrace_func_command *cmd)
4594 struct ftrace_func_command *p;
4597 mutex_lock(&ftrace_cmd_mutex);
4598 list_for_each_entry(p, &ftrace_commands, list) {
4599 if (strcmp(cmd->name, p->name) == 0) {
4604 list_add(&cmd->list, &ftrace_commands);
4606 mutex_unlock(&ftrace_cmd_mutex);
4612 * Currently we only unregister ftrace commands from __init, so mark
4615 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4617 struct ftrace_func_command *p, *n;
4620 mutex_lock(&ftrace_cmd_mutex);
4621 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4622 if (strcmp(cmd->name, p->name) == 0) {
4624 list_del_init(&p->list);
4629 mutex_unlock(&ftrace_cmd_mutex);
4634 static int ftrace_process_regex(struct ftrace_iterator *iter,
4635 char *buff, int len, int enable)
4637 struct ftrace_hash *hash = iter->hash;
4638 struct trace_array *tr = iter->ops->private;
4639 char *func, *command, *next = buff;
4640 struct ftrace_func_command *p;
4643 func = strsep(&next, ":");
4646 ret = ftrace_match_records(hash, func, len);
4656 command = strsep(&next, ":");
4658 mutex_lock(&ftrace_cmd_mutex);
4659 list_for_each_entry(p, &ftrace_commands, list) {
4660 if (strcmp(p->name, command) == 0) {
4661 ret = p->func(tr, hash, func, command, next, enable);
4666 mutex_unlock(&ftrace_cmd_mutex);
4672 ftrace_regex_write(struct file *file, const char __user *ubuf,
4673 size_t cnt, loff_t *ppos, int enable)
4675 struct ftrace_iterator *iter;
4676 struct trace_parser *parser;
4682 if (file->f_mode & FMODE_READ) {
4683 struct seq_file *m = file->private_data;
4686 iter = file->private_data;
4688 if (unlikely(ftrace_disabled))
4691 /* iter->hash is a local copy, so we don't need regex_lock */
4693 parser = &iter->parser;
4694 read = trace_get_user(parser, ubuf, cnt, ppos);
4696 if (read >= 0 && trace_parser_loaded(parser) &&
4697 !trace_parser_cont(parser)) {
4698 ret = ftrace_process_regex(iter, parser->buffer,
4699 parser->idx, enable);
4700 trace_parser_clear(parser);
4711 ftrace_filter_write(struct file *file, const char __user *ubuf,
4712 size_t cnt, loff_t *ppos)
4714 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4718 ftrace_notrace_write(struct file *file, const char __user *ubuf,
4719 size_t cnt, loff_t *ppos)
4721 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4725 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4727 struct ftrace_func_entry *entry;
4729 if (!ftrace_location(ip))
4733 entry = ftrace_lookup_ip(hash, ip);
4736 free_hash_entry(hash, entry);
4740 return add_hash_entry(hash, ip);
4744 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4745 unsigned long ip, int remove, int reset, int enable)
4747 struct ftrace_hash **orig_hash;
4748 struct ftrace_hash *hash;
4751 if (unlikely(ftrace_disabled))
4754 mutex_lock(&ops->func_hash->regex_lock);
4757 orig_hash = &ops->func_hash->filter_hash;
4759 orig_hash = &ops->func_hash->notrace_hash;
4762 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4764 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4768 goto out_regex_unlock;
4771 if (buf && !ftrace_match_records(hash, buf, len)) {
4773 goto out_regex_unlock;
4776 ret = ftrace_match_addr(hash, ip, remove);
4778 goto out_regex_unlock;
4781 mutex_lock(&ftrace_lock);
4782 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
4783 mutex_unlock(&ftrace_lock);
4786 mutex_unlock(&ops->func_hash->regex_lock);
4788 free_ftrace_hash(hash);
4793 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
4794 int reset, int enable)
4796 return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
4800 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
4801 * @ops - the ops to set the filter with
4802 * @ip - the address to add to or remove from the filter.
4803 * @remove - non zero to remove the ip from the filter
4804 * @reset - non zero to reset all filters before applying this filter.
4806 * Filters denote which functions should be enabled when tracing is enabled
4807 * If @ip is NULL, it failes to update filter.
4809 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
4810 int remove, int reset)
4812 ftrace_ops_init(ops);
4813 return ftrace_set_addr(ops, ip, remove, reset, 1);
4815 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
4818 * ftrace_ops_set_global_filter - setup ops to use global filters
4819 * @ops - the ops which will use the global filters
4821 * ftrace users who need global function trace filtering should call this.
4822 * It can set the global filter only if ops were not initialized before.
4824 void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
4826 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
4829 ftrace_ops_init(ops);
4830 ops->func_hash = &global_ops.local_hash;
4832 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
4835 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4836 int reset, int enable)
4838 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
4842 * ftrace_set_filter - set a function to filter on in ftrace
4843 * @ops - the ops to set the filter with
4844 * @buf - the string that holds the function filter text.
4845 * @len - the length of the string.
4846 * @reset - non zero to reset all filters before applying this filter.
4848 * Filters denote which functions should be enabled when tracing is enabled.
4849 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4851 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
4854 ftrace_ops_init(ops);
4855 return ftrace_set_regex(ops, buf, len, reset, 1);
4857 EXPORT_SYMBOL_GPL(ftrace_set_filter);
4860 * ftrace_set_notrace - set a function to not trace in ftrace
4861 * @ops - the ops to set the notrace filter with
4862 * @buf - the string that holds the function notrace text.
4863 * @len - the length of the string.
4864 * @reset - non zero to reset all filters before applying this filter.
4866 * Notrace Filters denote which functions should not be enabled when tracing
4867 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4870 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
4873 ftrace_ops_init(ops);
4874 return ftrace_set_regex(ops, buf, len, reset, 0);
4876 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
4878 * ftrace_set_global_filter - set a function to filter on with global tracers
4879 * @buf - the string that holds the function filter text.
4880 * @len - the length of the string.
4881 * @reset - non zero to reset all filters before applying this filter.
4883 * Filters denote which functions should be enabled when tracing is enabled.
4884 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4886 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
4888 ftrace_set_regex(&global_ops, buf, len, reset, 1);
4890 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
4893 * ftrace_set_global_notrace - set a function to not trace with global tracers
4894 * @buf - the string that holds the function notrace text.
4895 * @len - the length of the string.
4896 * @reset - non zero to reset all filters before applying this filter.
4898 * Notrace Filters denote which functions should not be enabled when tracing
4899 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4902 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
4904 ftrace_set_regex(&global_ops, buf, len, reset, 0);
4906 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
4909 * command line interface to allow users to set filters on boot up.
4911 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
4912 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4913 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
4915 /* Used by function selftest to not test if filter is set */
4916 bool ftrace_filter_param __initdata;
4918 static int __init set_ftrace_notrace(char *str)
4920 ftrace_filter_param = true;
4921 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
4924 __setup("ftrace_notrace=", set_ftrace_notrace);
4926 static int __init set_ftrace_filter(char *str)
4928 ftrace_filter_param = true;
4929 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
4932 __setup("ftrace_filter=", set_ftrace_filter);
4934 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4935 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
4936 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4937 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
4939 static unsigned long save_global_trampoline;
4940 static unsigned long save_global_flags;
4942 static int __init set_graph_function(char *str)
4944 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
4947 __setup("ftrace_graph_filter=", set_graph_function);
4949 static int __init set_graph_notrace_function(char *str)
4951 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
4954 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
4956 static int __init set_graph_max_depth_function(char *str)
4960 fgraph_max_depth = simple_strtoul(str, NULL, 0);
4963 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
4965 static void __init set_ftrace_early_graph(char *buf, int enable)
4969 struct ftrace_hash *hash;
4971 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4976 func = strsep(&buf, ",");
4977 /* we allow only one expression at a time */
4978 ret = ftrace_graph_set_hash(hash, func);
4980 printk(KERN_DEBUG "ftrace: function %s not "
4981 "traceable\n", func);
4985 ftrace_graph_hash = hash;
4987 ftrace_graph_notrace_hash = hash;
4989 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4992 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
4996 ftrace_ops_init(ops);
4999 func = strsep(&buf, ",");
5000 ftrace_set_regex(ops, func, strlen(func), 0, enable);
5004 static void __init set_ftrace_early_filters(void)
5006 if (ftrace_filter_buf[0])
5007 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
5008 if (ftrace_notrace_buf[0])
5009 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
5010 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5011 if (ftrace_graph_buf[0])
5012 set_ftrace_early_graph(ftrace_graph_buf, 1);
5013 if (ftrace_graph_notrace_buf[0])
5014 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
5015 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5018 int ftrace_regex_release(struct inode *inode, struct file *file)
5020 struct seq_file *m = (struct seq_file *)file->private_data;
5021 struct ftrace_iterator *iter;
5022 struct ftrace_hash **orig_hash;
5023 struct trace_parser *parser;
5027 if (file->f_mode & FMODE_READ) {
5029 seq_release(inode, file);
5031 iter = file->private_data;
5033 parser = &iter->parser;
5034 if (trace_parser_loaded(parser)) {
5035 parser->buffer[parser->idx] = 0;
5036 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
5039 trace_parser_put(parser);
5041 mutex_lock(&iter->ops->func_hash->regex_lock);
5043 if (file->f_mode & FMODE_WRITE) {
5044 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5047 orig_hash = &iter->ops->func_hash->filter_hash;
5048 if (iter->tr && !list_empty(&iter->tr->mod_trace))
5049 iter->hash->flags |= FTRACE_HASH_FL_MOD;
5051 orig_hash = &iter->ops->func_hash->notrace_hash;
5053 mutex_lock(&ftrace_lock);
5054 ret = ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5055 iter->hash, filter_hash);
5056 mutex_unlock(&ftrace_lock);
5058 /* For read only, the hash is the ops hash */
5062 mutex_unlock(&iter->ops->func_hash->regex_lock);
5063 free_ftrace_hash(iter->hash);
5069 static const struct file_operations ftrace_avail_fops = {
5070 .open = ftrace_avail_open,
5072 .llseek = seq_lseek,
5073 .release = seq_release_private,
5076 static const struct file_operations ftrace_enabled_fops = {
5077 .open = ftrace_enabled_open,
5079 .llseek = seq_lseek,
5080 .release = seq_release_private,
5083 static const struct file_operations ftrace_filter_fops = {
5084 .open = ftrace_filter_open,
5086 .write = ftrace_filter_write,
5087 .llseek = tracing_lseek,
5088 .release = ftrace_regex_release,
5091 static const struct file_operations ftrace_notrace_fops = {
5092 .open = ftrace_notrace_open,
5094 .write = ftrace_notrace_write,
5095 .llseek = tracing_lseek,
5096 .release = ftrace_regex_release,
5099 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5101 static DEFINE_MUTEX(graph_lock);
5103 struct ftrace_hash *ftrace_graph_hash = EMPTY_HASH;
5104 struct ftrace_hash *ftrace_graph_notrace_hash = EMPTY_HASH;
5106 enum graph_filter_type {
5107 GRAPH_FILTER_NOTRACE = 0,
5108 GRAPH_FILTER_FUNCTION,
5111 #define FTRACE_GRAPH_EMPTY ((void *)1)
5113 struct ftrace_graph_data {
5114 struct ftrace_hash *hash;
5115 struct ftrace_func_entry *entry;
5116 int idx; /* for hash table iteration */
5117 enum graph_filter_type type;
5118 struct ftrace_hash *new_hash;
5119 const struct seq_operations *seq_ops;
5120 struct trace_parser parser;
5124 __g_next(struct seq_file *m, loff_t *pos)
5126 struct ftrace_graph_data *fgd = m->private;
5127 struct ftrace_func_entry *entry = fgd->entry;
5128 struct hlist_head *head;
5129 int i, idx = fgd->idx;
5131 if (*pos >= fgd->hash->count)
5135 hlist_for_each_entry_continue(entry, hlist) {
5143 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
5144 head = &fgd->hash->buckets[i];
5145 hlist_for_each_entry(entry, head, hlist) {
5155 g_next(struct seq_file *m, void *v, loff_t *pos)
5158 return __g_next(m, pos);
5161 static void *g_start(struct seq_file *m, loff_t *pos)
5163 struct ftrace_graph_data *fgd = m->private;
5165 mutex_lock(&graph_lock);
5167 if (fgd->type == GRAPH_FILTER_FUNCTION)
5168 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5169 lockdep_is_held(&graph_lock));
5171 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5172 lockdep_is_held(&graph_lock));
5174 /* Nothing, tell g_show to print all functions are enabled */
5175 if (ftrace_hash_empty(fgd->hash) && !*pos)
5176 return FTRACE_GRAPH_EMPTY;
5180 return __g_next(m, pos);
5183 static void g_stop(struct seq_file *m, void *p)
5185 mutex_unlock(&graph_lock);
5188 static int g_show(struct seq_file *m, void *v)
5190 struct ftrace_func_entry *entry = v;
5195 if (entry == FTRACE_GRAPH_EMPTY) {
5196 struct ftrace_graph_data *fgd = m->private;
5198 if (fgd->type == GRAPH_FILTER_FUNCTION)
5199 seq_puts(m, "#### all functions enabled ####\n");
5201 seq_puts(m, "#### no functions disabled ####\n");
5205 seq_printf(m, "%ps\n", (void *)entry->ip);
5210 static const struct seq_operations ftrace_graph_seq_ops = {
5218 __ftrace_graph_open(struct inode *inode, struct file *file,
5219 struct ftrace_graph_data *fgd)
5222 struct ftrace_hash *new_hash = NULL;
5224 if (file->f_mode & FMODE_WRITE) {
5225 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
5227 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
5230 if (file->f_flags & O_TRUNC)
5231 new_hash = alloc_ftrace_hash(size_bits);
5233 new_hash = alloc_and_copy_ftrace_hash(size_bits,
5241 if (file->f_mode & FMODE_READ) {
5242 ret = seq_open(file, &ftrace_graph_seq_ops);
5244 struct seq_file *m = file->private_data;
5248 free_ftrace_hash(new_hash);
5252 file->private_data = fgd;
5255 if (ret < 0 && file->f_mode & FMODE_WRITE)
5256 trace_parser_put(&fgd->parser);
5258 fgd->new_hash = new_hash;
5261 * All uses of fgd->hash must be taken with the graph_lock
5262 * held. The graph_lock is going to be released, so force
5263 * fgd->hash to be reinitialized when it is taken again.
5271 ftrace_graph_open(struct inode *inode, struct file *file)
5273 struct ftrace_graph_data *fgd;
5276 if (unlikely(ftrace_disabled))
5279 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5283 mutex_lock(&graph_lock);
5285 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5286 lockdep_is_held(&graph_lock));
5287 fgd->type = GRAPH_FILTER_FUNCTION;
5288 fgd->seq_ops = &ftrace_graph_seq_ops;
5290 ret = __ftrace_graph_open(inode, file, fgd);
5294 mutex_unlock(&graph_lock);
5299 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
5301 struct ftrace_graph_data *fgd;
5304 if (unlikely(ftrace_disabled))
5307 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5311 mutex_lock(&graph_lock);
5313 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5314 lockdep_is_held(&graph_lock));
5315 fgd->type = GRAPH_FILTER_NOTRACE;
5316 fgd->seq_ops = &ftrace_graph_seq_ops;
5318 ret = __ftrace_graph_open(inode, file, fgd);
5322 mutex_unlock(&graph_lock);
5327 ftrace_graph_release(struct inode *inode, struct file *file)
5329 struct ftrace_graph_data *fgd;
5330 struct ftrace_hash *old_hash, *new_hash;
5331 struct trace_parser *parser;
5334 if (file->f_mode & FMODE_READ) {
5335 struct seq_file *m = file->private_data;
5338 seq_release(inode, file);
5340 fgd = file->private_data;
5344 if (file->f_mode & FMODE_WRITE) {
5346 parser = &fgd->parser;
5348 if (trace_parser_loaded((parser))) {
5349 parser->buffer[parser->idx] = 0;
5350 ret = ftrace_graph_set_hash(fgd->new_hash,
5354 trace_parser_put(parser);
5356 new_hash = __ftrace_hash_move(fgd->new_hash);
5362 mutex_lock(&graph_lock);
5364 if (fgd->type == GRAPH_FILTER_FUNCTION) {
5365 old_hash = rcu_dereference_protected(ftrace_graph_hash,
5366 lockdep_is_held(&graph_lock));
5367 rcu_assign_pointer(ftrace_graph_hash, new_hash);
5369 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5370 lockdep_is_held(&graph_lock));
5371 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
5374 mutex_unlock(&graph_lock);
5376 /* Wait till all users are no longer using the old hash */
5377 synchronize_sched();
5379 free_ftrace_hash(old_hash);
5383 free_ftrace_hash(fgd->new_hash);
5390 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
5392 struct ftrace_glob func_g;
5393 struct dyn_ftrace *rec;
5394 struct ftrace_page *pg;
5395 struct ftrace_func_entry *entry;
5400 func_g.type = filter_parse_regex(buffer, strlen(buffer),
5401 &func_g.search, ¬);
5403 func_g.len = strlen(func_g.search);
5405 mutex_lock(&ftrace_lock);
5407 if (unlikely(ftrace_disabled)) {
5408 mutex_unlock(&ftrace_lock);
5412 do_for_each_ftrace_rec(pg, rec) {
5414 if (rec->flags & FTRACE_FL_DISABLED)
5417 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
5418 entry = ftrace_lookup_ip(hash, rec->ip);
5425 if (add_hash_entry(hash, rec->ip) < 0)
5429 free_hash_entry(hash, entry);
5434 } while_for_each_ftrace_rec();
5436 mutex_unlock(&ftrace_lock);
5445 ftrace_graph_write(struct file *file, const char __user *ubuf,
5446 size_t cnt, loff_t *ppos)
5448 ssize_t read, ret = 0;
5449 struct ftrace_graph_data *fgd = file->private_data;
5450 struct trace_parser *parser;
5455 /* Read mode uses seq functions */
5456 if (file->f_mode & FMODE_READ) {
5457 struct seq_file *m = file->private_data;
5461 parser = &fgd->parser;
5463 read = trace_get_user(parser, ubuf, cnt, ppos);
5465 if (read >= 0 && trace_parser_loaded(parser) &&
5466 !trace_parser_cont(parser)) {
5468 ret = ftrace_graph_set_hash(fgd->new_hash,
5470 trace_parser_clear(parser);
5479 static const struct file_operations ftrace_graph_fops = {
5480 .open = ftrace_graph_open,
5482 .write = ftrace_graph_write,
5483 .llseek = tracing_lseek,
5484 .release = ftrace_graph_release,
5487 static const struct file_operations ftrace_graph_notrace_fops = {
5488 .open = ftrace_graph_notrace_open,
5490 .write = ftrace_graph_write,
5491 .llseek = tracing_lseek,
5492 .release = ftrace_graph_release,
5494 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5496 void ftrace_create_filter_files(struct ftrace_ops *ops,
5497 struct dentry *parent)
5500 trace_create_file("set_ftrace_filter", 0644, parent,
5501 ops, &ftrace_filter_fops);
5503 trace_create_file("set_ftrace_notrace", 0644, parent,
5504 ops, &ftrace_notrace_fops);
5508 * The name "destroy_filter_files" is really a misnomer. Although
5509 * in the future, it may actualy delete the files, but this is
5510 * really intended to make sure the ops passed in are disabled
5511 * and that when this function returns, the caller is free to
5514 * The "destroy" name is only to match the "create" name that this
5515 * should be paired with.
5517 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
5519 mutex_lock(&ftrace_lock);
5520 if (ops->flags & FTRACE_OPS_FL_ENABLED)
5521 ftrace_shutdown(ops, 0);
5522 ops->flags |= FTRACE_OPS_FL_DELETED;
5523 mutex_unlock(&ftrace_lock);
5526 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
5529 trace_create_file("available_filter_functions", 0444,
5530 d_tracer, NULL, &ftrace_avail_fops);
5532 trace_create_file("enabled_functions", 0444,
5533 d_tracer, NULL, &ftrace_enabled_fops);
5535 ftrace_create_filter_files(&global_ops, d_tracer);
5537 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5538 trace_create_file("set_graph_function", 0444, d_tracer,
5540 &ftrace_graph_fops);
5541 trace_create_file("set_graph_notrace", 0444, d_tracer,
5543 &ftrace_graph_notrace_fops);
5544 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5549 static int ftrace_cmp_ips(const void *a, const void *b)
5551 const unsigned long *ipa = a;
5552 const unsigned long *ipb = b;
5561 static int ftrace_process_locs(struct module *mod,
5562 unsigned long *start,
5565 struct ftrace_page *start_pg;
5566 struct ftrace_page *pg;
5567 struct dyn_ftrace *rec;
5568 unsigned long count;
5571 unsigned long flags = 0; /* Shut up gcc */
5574 count = end - start;
5579 sort(start, count, sizeof(*start),
5580 ftrace_cmp_ips, NULL);
5582 start_pg = ftrace_allocate_pages(count);
5586 mutex_lock(&ftrace_lock);
5589 * Core and each module needs their own pages, as
5590 * modules will free them when they are removed.
5591 * Force a new page to be allocated for modules.
5594 WARN_ON(ftrace_pages || ftrace_pages_start);
5595 /* First initialization */
5596 ftrace_pages = ftrace_pages_start = start_pg;
5601 if (WARN_ON(ftrace_pages->next)) {
5602 /* Hmm, we have free pages? */
5603 while (ftrace_pages->next)
5604 ftrace_pages = ftrace_pages->next;
5607 ftrace_pages->next = start_pg;
5613 addr = ftrace_call_adjust(*p++);
5615 * Some architecture linkers will pad between
5616 * the different mcount_loc sections of different
5617 * object files to satisfy alignments.
5618 * Skip any NULL pointers.
5623 if (pg->index == pg->size) {
5624 /* We should have allocated enough */
5625 if (WARN_ON(!pg->next))
5630 rec = &pg->records[pg->index++];
5634 /* We should have used all pages */
5637 /* Assign the last page to ftrace_pages */
5641 * We only need to disable interrupts on start up
5642 * because we are modifying code that an interrupt
5643 * may execute, and the modification is not atomic.
5644 * But for modules, nothing runs the code we modify
5645 * until we are finished with it, and there's no
5646 * reason to cause large interrupt latencies while we do it.
5649 local_irq_save(flags);
5650 ftrace_update_code(mod, start_pg);
5652 local_irq_restore(flags);
5655 mutex_unlock(&ftrace_lock);
5660 #ifdef CONFIG_MODULES
5662 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
5664 static int referenced_filters(struct dyn_ftrace *rec)
5666 struct ftrace_ops *ops;
5669 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
5670 if (ops_references_rec(ops, rec))
5677 void ftrace_release_mod(struct module *mod)
5679 struct dyn_ftrace *rec;
5680 struct ftrace_page **last_pg;
5681 struct ftrace_page *pg;
5684 mutex_lock(&ftrace_lock);
5686 if (ftrace_disabled)
5690 * Each module has its own ftrace_pages, remove
5691 * them from the list.
5693 last_pg = &ftrace_pages_start;
5694 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
5695 rec = &pg->records[0];
5696 if (within_module_core(rec->ip, mod)) {
5698 * As core pages are first, the first
5699 * page should never be a module page.
5701 if (WARN_ON(pg == ftrace_pages_start))
5704 /* Check if we are deleting the last page */
5705 if (pg == ftrace_pages)
5706 ftrace_pages = next_to_ftrace_page(last_pg);
5708 ftrace_update_tot_cnt -= pg->index;
5709 *last_pg = pg->next;
5710 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
5711 free_pages((unsigned long)pg->records, order);
5714 last_pg = &pg->next;
5717 mutex_unlock(&ftrace_lock);
5720 void ftrace_module_enable(struct module *mod)
5722 struct dyn_ftrace *rec;
5723 struct ftrace_page *pg;
5725 mutex_lock(&ftrace_lock);
5727 if (ftrace_disabled)
5731 * If the tracing is enabled, go ahead and enable the record.
5733 * The reason not to enable the record immediatelly is the
5734 * inherent check of ftrace_make_nop/ftrace_make_call for
5735 * correct previous instructions. Making first the NOP
5736 * conversion puts the module to the correct state, thus
5737 * passing the ftrace_make_call check.
5739 * We also delay this to after the module code already set the
5740 * text to read-only, as we now need to set it back to read-write
5741 * so that we can modify the text.
5743 if (ftrace_start_up)
5744 ftrace_arch_code_modify_prepare();
5746 do_for_each_ftrace_rec(pg, rec) {
5749 * do_for_each_ftrace_rec() is a double loop.
5750 * module text shares the pg. If a record is
5751 * not part of this module, then skip this pg,
5752 * which the "break" will do.
5754 if (!within_module_core(rec->ip, mod))
5760 * When adding a module, we need to check if tracers are
5761 * currently enabled and if they are, and can trace this record,
5762 * we need to enable the module functions as well as update the
5763 * reference counts for those function records.
5765 if (ftrace_start_up)
5766 cnt += referenced_filters(rec);
5768 /* This clears FTRACE_FL_DISABLED */
5771 if (ftrace_start_up && cnt) {
5772 int failed = __ftrace_replace_code(rec, 1);
5774 ftrace_bug(failed, rec);
5779 } while_for_each_ftrace_rec();
5782 if (ftrace_start_up)
5783 ftrace_arch_code_modify_post_process();
5786 mutex_unlock(&ftrace_lock);
5788 process_cached_mods(mod->name);
5791 void ftrace_module_init(struct module *mod)
5793 if (ftrace_disabled || !mod->num_ftrace_callsites)
5796 ftrace_process_locs(mod, mod->ftrace_callsites,
5797 mod->ftrace_callsites + mod->num_ftrace_callsites);
5799 #endif /* CONFIG_MODULES */
5801 void __init ftrace_free_init_mem(void)
5803 unsigned long start = (unsigned long)(&__init_begin);
5804 unsigned long end = (unsigned long)(&__init_end);
5805 struct ftrace_page **last_pg = &ftrace_pages_start;
5806 struct ftrace_page *pg;
5807 struct dyn_ftrace *rec;
5808 struct dyn_ftrace key;
5812 key.flags = end; /* overload flags, as it is unsigned long */
5814 mutex_lock(&ftrace_lock);
5816 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
5817 if (end < pg->records[0].ip ||
5818 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
5821 rec = bsearch(&key, pg->records, pg->index,
5822 sizeof(struct dyn_ftrace),
5827 ftrace_update_tot_cnt--;
5829 *last_pg = pg->next;
5830 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
5831 free_pages((unsigned long)pg->records, order);
5833 pg = container_of(last_pg, struct ftrace_page, next);
5838 memmove(rec, rec + 1,
5839 (pg->index - (rec - pg->records)) * sizeof(*rec));
5840 /* More than one function may be in this block */
5843 mutex_unlock(&ftrace_lock);
5846 void __init ftrace_init(void)
5848 extern unsigned long __start_mcount_loc[];
5849 extern unsigned long __stop_mcount_loc[];
5850 unsigned long count, flags;
5853 local_irq_save(flags);
5854 ret = ftrace_dyn_arch_init();
5855 local_irq_restore(flags);
5859 count = __stop_mcount_loc - __start_mcount_loc;
5861 pr_info("ftrace: No functions to be traced?\n");
5865 pr_info("ftrace: allocating %ld entries in %ld pages\n",
5866 count, count / ENTRIES_PER_PAGE + 1);
5868 last_ftrace_enabled = ftrace_enabled = 1;
5870 ret = ftrace_process_locs(NULL,
5874 set_ftrace_early_filters();
5878 ftrace_disabled = 1;
5881 /* Do nothing if arch does not support this */
5882 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
5886 static void ftrace_update_trampoline(struct ftrace_ops *ops)
5888 arch_ftrace_update_trampoline(ops);
5891 void ftrace_init_trace_array(struct trace_array *tr)
5893 INIT_LIST_HEAD(&tr->func_probes);
5894 INIT_LIST_HEAD(&tr->mod_trace);
5895 INIT_LIST_HEAD(&tr->mod_notrace);
5899 static struct ftrace_ops global_ops = {
5900 .func = ftrace_stub,
5901 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
5902 FTRACE_OPS_FL_INITIALIZED |
5906 static int __init ftrace_nodyn_init(void)
5911 core_initcall(ftrace_nodyn_init);
5913 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
5914 static inline void ftrace_startup_enable(int command) { }
5915 static inline void ftrace_startup_all(int command) { }
5916 /* Keep as macros so we do not need to define the commands */
5917 # define ftrace_startup(ops, command) \
5919 int ___ret = __register_ftrace_function(ops); \
5921 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
5924 # define ftrace_shutdown(ops, command) \
5926 int ___ret = __unregister_ftrace_function(ops); \
5928 (ops)->flags &= ~FTRACE_OPS_FL_ENABLED; \
5932 # define ftrace_startup_sysctl() do { } while (0)
5933 # define ftrace_shutdown_sysctl() do { } while (0)
5936 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
5941 static void ftrace_update_trampoline(struct ftrace_ops *ops)
5945 #endif /* CONFIG_DYNAMIC_FTRACE */
5947 __init void ftrace_init_global_array_ops(struct trace_array *tr)
5949 tr->ops = &global_ops;
5950 tr->ops->private = tr;
5951 ftrace_init_trace_array(tr);
5954 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
5956 /* If we filter on pids, update to use the pid function */
5957 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
5958 if (WARN_ON(tr->ops->func != ftrace_stub))
5959 printk("ftrace ops had %pS for function\n",
5962 tr->ops->func = func;
5963 tr->ops->private = tr;
5966 void ftrace_reset_array_ops(struct trace_array *tr)
5968 tr->ops->func = ftrace_stub;
5972 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
5973 struct ftrace_ops *ignored, struct pt_regs *regs)
5975 struct ftrace_ops *op;
5978 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
5983 * Some of the ops may be dynamically allocated,
5984 * they must be freed after a synchronize_sched().
5986 preempt_disable_notrace();
5988 do_for_each_ftrace_op(op, ftrace_ops_list) {
5990 * Check the following for each ops before calling their func:
5991 * if RCU flag is set, then rcu_is_watching() must be true
5992 * if PER_CPU is set, then ftrace_function_local_disable()
5994 * Otherwise test if the ip matches the ops filter
5996 * If any of the above fails then the op->func() is not executed.
5998 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
5999 (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
6000 !ftrace_function_local_disabled(op)) &&
6001 ftrace_ops_test(op, ip, regs)) {
6003 if (FTRACE_WARN_ON(!op->func)) {
6004 pr_warn("op=%p %pS\n", op, op);
6007 op->func(ip, parent_ip, op, regs);
6009 } while_for_each_ftrace_op(op);
6011 preempt_enable_notrace();
6012 trace_clear_recursion(bit);
6016 * Some archs only support passing ip and parent_ip. Even though
6017 * the list function ignores the op parameter, we do not want any
6018 * C side effects, where a function is called without the caller
6019 * sending a third parameter.
6020 * Archs are to support both the regs and ftrace_ops at the same time.
6021 * If they support ftrace_ops, it is assumed they support regs.
6022 * If call backs want to use regs, they must either check for regs
6023 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
6024 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
6025 * An architecture can pass partial regs with ftrace_ops and still
6026 * set the ARCH_SUPPORTS_FTRACE_OPS.
6028 #if ARCH_SUPPORTS_FTRACE_OPS
6029 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6030 struct ftrace_ops *op, struct pt_regs *regs)
6032 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
6035 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
6037 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
6042 * If there's only one function registered but it does not support
6043 * recursion, needs RCU protection and/or requires per cpu handling, then
6044 * this function will be called by the mcount trampoline.
6046 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
6047 struct ftrace_ops *op, struct pt_regs *regs)
6051 if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching())
6054 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
6058 preempt_disable_notrace();
6060 if (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
6061 !ftrace_function_local_disabled(op)) {
6062 op->func(ip, parent_ip, op, regs);
6065 preempt_enable_notrace();
6066 trace_clear_recursion(bit);
6070 * ftrace_ops_get_func - get the function a trampoline should call
6071 * @ops: the ops to get the function for
6073 * Normally the mcount trampoline will call the ops->func, but there
6074 * are times that it should not. For example, if the ops does not
6075 * have its own recursion protection, then it should call the
6076 * ftrace_ops_assist_func() instead.
6078 * Returns the function that the trampoline should call for @ops.
6080 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
6083 * If the function does not handle recursion, needs to be RCU safe,
6084 * or does per cpu logic, then we need to call the assist handler.
6086 if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
6087 ops->flags & (FTRACE_OPS_FL_RCU | FTRACE_OPS_FL_PER_CPU))
6088 return ftrace_ops_assist_func;
6094 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
6095 struct task_struct *prev, struct task_struct *next)
6097 struct trace_array *tr = data;
6098 struct trace_pid_list *pid_list;
6100 pid_list = rcu_dereference_sched(tr->function_pids);
6102 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
6103 trace_ignore_this_task(pid_list, next));
6107 ftrace_pid_follow_sched_process_fork(void *data,
6108 struct task_struct *self,
6109 struct task_struct *task)
6111 struct trace_pid_list *pid_list;
6112 struct trace_array *tr = data;
6114 pid_list = rcu_dereference_sched(tr->function_pids);
6115 trace_filter_add_remove_task(pid_list, self, task);
6119 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
6121 struct trace_pid_list *pid_list;
6122 struct trace_array *tr = data;
6124 pid_list = rcu_dereference_sched(tr->function_pids);
6125 trace_filter_add_remove_task(pid_list, NULL, task);
6128 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
6131 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6133 register_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit,
6136 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6138 unregister_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit,
6143 static void clear_ftrace_pids(struct trace_array *tr)
6145 struct trace_pid_list *pid_list;
6148 pid_list = rcu_dereference_protected(tr->function_pids,
6149 lockdep_is_held(&ftrace_lock));
6153 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
6155 for_each_possible_cpu(cpu)
6156 per_cpu_ptr(tr->trace_buffer.data, cpu)->ftrace_ignore_pid = false;
6158 rcu_assign_pointer(tr->function_pids, NULL);
6160 /* Wait till all users are no longer using pid filtering */
6161 synchronize_sched();
6163 trace_free_pid_list(pid_list);
6166 void ftrace_clear_pids(struct trace_array *tr)
6168 mutex_lock(&ftrace_lock);
6170 clear_ftrace_pids(tr);
6172 mutex_unlock(&ftrace_lock);
6175 static void ftrace_pid_reset(struct trace_array *tr)
6177 mutex_lock(&ftrace_lock);
6178 clear_ftrace_pids(tr);
6180 ftrace_update_pid_func();
6181 ftrace_startup_all(0);
6183 mutex_unlock(&ftrace_lock);
6186 /* Greater than any max PID */
6187 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
6189 static void *fpid_start(struct seq_file *m, loff_t *pos)
6192 struct trace_pid_list *pid_list;
6193 struct trace_array *tr = m->private;
6195 mutex_lock(&ftrace_lock);
6196 rcu_read_lock_sched();
6198 pid_list = rcu_dereference_sched(tr->function_pids);
6201 return !(*pos) ? FTRACE_NO_PIDS : NULL;
6203 return trace_pid_start(pid_list, pos);
6206 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
6208 struct trace_array *tr = m->private;
6209 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
6211 if (v == FTRACE_NO_PIDS)
6214 return trace_pid_next(pid_list, v, pos);
6217 static void fpid_stop(struct seq_file *m, void *p)
6220 rcu_read_unlock_sched();
6221 mutex_unlock(&ftrace_lock);
6224 static int fpid_show(struct seq_file *m, void *v)
6226 if (v == FTRACE_NO_PIDS) {
6227 seq_puts(m, "no pid\n");
6231 return trace_pid_show(m, v);
6234 static const struct seq_operations ftrace_pid_sops = {
6235 .start = fpid_start,
6242 ftrace_pid_open(struct inode *inode, struct file *file)
6244 struct trace_array *tr = inode->i_private;
6248 if (trace_array_get(tr) < 0)
6251 if ((file->f_mode & FMODE_WRITE) &&
6252 (file->f_flags & O_TRUNC))
6253 ftrace_pid_reset(tr);
6255 ret = seq_open(file, &ftrace_pid_sops);
6257 trace_array_put(tr);
6259 m = file->private_data;
6260 /* copy tr over to seq ops */
6267 static void ignore_task_cpu(void *data)
6269 struct trace_array *tr = data;
6270 struct trace_pid_list *pid_list;
6273 * This function is called by on_each_cpu() while the
6274 * event_mutex is held.
6276 pid_list = rcu_dereference_protected(tr->function_pids,
6277 mutex_is_locked(&ftrace_lock));
6279 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
6280 trace_ignore_this_task(pid_list, current));
6284 ftrace_pid_write(struct file *filp, const char __user *ubuf,
6285 size_t cnt, loff_t *ppos)
6287 struct seq_file *m = filp->private_data;
6288 struct trace_array *tr = m->private;
6289 struct trace_pid_list *filtered_pids = NULL;
6290 struct trace_pid_list *pid_list;
6296 mutex_lock(&ftrace_lock);
6298 filtered_pids = rcu_dereference_protected(tr->function_pids,
6299 lockdep_is_held(&ftrace_lock));
6301 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
6305 rcu_assign_pointer(tr->function_pids, pid_list);
6307 if (filtered_pids) {
6308 synchronize_sched();
6309 trace_free_pid_list(filtered_pids);
6310 } else if (pid_list) {
6311 /* Register a probe to set whether to ignore the tracing of a task */
6312 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
6316 * Ignoring of pids is done at task switch. But we have to
6317 * check for those tasks that are currently running.
6318 * Always do this in case a pid was appended or removed.
6320 on_each_cpu(ignore_task_cpu, tr, 1);
6322 ftrace_update_pid_func();
6323 ftrace_startup_all(0);
6325 mutex_unlock(&ftrace_lock);
6334 ftrace_pid_release(struct inode *inode, struct file *file)
6336 struct trace_array *tr = inode->i_private;
6338 trace_array_put(tr);
6340 return seq_release(inode, file);
6343 static const struct file_operations ftrace_pid_fops = {
6344 .open = ftrace_pid_open,
6345 .write = ftrace_pid_write,
6347 .llseek = tracing_lseek,
6348 .release = ftrace_pid_release,
6351 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
6353 trace_create_file("set_ftrace_pid", 0644, d_tracer,
6354 tr, &ftrace_pid_fops);
6357 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
6358 struct dentry *d_tracer)
6360 /* Only the top level directory has the dyn_tracefs and profile */
6361 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
6363 ftrace_init_dyn_tracefs(d_tracer);
6364 ftrace_profile_tracefs(d_tracer);
6368 * ftrace_kill - kill ftrace
6370 * This function should be used by panic code. It stops ftrace
6371 * but in a not so nice way. If you need to simply kill ftrace
6372 * from a non-atomic section, use ftrace_kill.
6374 void ftrace_kill(void)
6376 ftrace_disabled = 1;
6378 clear_ftrace_function();
6382 * Test if ftrace is dead or not.
6384 int ftrace_is_dead(void)
6386 return ftrace_disabled;
6390 * register_ftrace_function - register a function for profiling
6391 * @ops - ops structure that holds the function for profiling.
6393 * Register a function to be called by all functions in the
6396 * Note: @ops->func and all the functions it calls must be labeled
6397 * with "notrace", otherwise it will go into a
6400 int register_ftrace_function(struct ftrace_ops *ops)
6404 ftrace_ops_init(ops);
6406 mutex_lock(&ftrace_lock);
6408 ret = ftrace_startup(ops, 0);
6410 mutex_unlock(&ftrace_lock);
6414 EXPORT_SYMBOL_GPL(register_ftrace_function);
6417 * unregister_ftrace_function - unregister a function for profiling.
6418 * @ops - ops structure that holds the function to unregister
6420 * Unregister a function that was added to be called by ftrace profiling.
6422 int unregister_ftrace_function(struct ftrace_ops *ops)
6426 mutex_lock(&ftrace_lock);
6427 ret = ftrace_shutdown(ops, 0);
6428 mutex_unlock(&ftrace_lock);
6432 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
6435 ftrace_enable_sysctl(struct ctl_table *table, int write,
6436 void __user *buffer, size_t *lenp,
6441 mutex_lock(&ftrace_lock);
6443 if (unlikely(ftrace_disabled))
6446 ret = proc_dointvec(table, write, buffer, lenp, ppos);
6448 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
6451 last_ftrace_enabled = !!ftrace_enabled;
6453 if (ftrace_enabled) {
6455 /* we are starting ftrace again */
6456 if (ftrace_ops_list != &ftrace_list_end)
6457 update_ftrace_function();
6459 ftrace_startup_sysctl();
6462 /* stopping ftrace calls (just send to ftrace_stub) */
6463 ftrace_trace_function = ftrace_stub;
6465 ftrace_shutdown_sysctl();
6469 mutex_unlock(&ftrace_lock);
6473 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
6475 static struct ftrace_ops graph_ops = {
6476 .func = ftrace_stub,
6477 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
6478 FTRACE_OPS_FL_INITIALIZED |
6481 #ifdef FTRACE_GRAPH_TRAMP_ADDR
6482 .trampoline = FTRACE_GRAPH_TRAMP_ADDR,
6483 /* trampoline_size is only needed for dynamically allocated tramps */
6485 ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash)
6488 void ftrace_graph_sleep_time_control(bool enable)
6490 fgraph_sleep_time = enable;
6493 void ftrace_graph_graph_time_control(bool enable)
6495 fgraph_graph_time = enable;
6498 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
6503 /* The callbacks that hook a function */
6504 trace_func_graph_ret_t ftrace_graph_return =
6505 (trace_func_graph_ret_t)ftrace_stub;
6506 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
6507 static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
6509 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
6510 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
6514 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
6515 struct task_struct *g, *t;
6517 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
6518 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
6519 * sizeof(struct ftrace_ret_stack),
6521 if (!ret_stack_list[i]) {
6529 read_lock(&tasklist_lock);
6530 do_each_thread(g, t) {
6536 if (t->ret_stack == NULL) {
6537 atomic_set(&t->tracing_graph_pause, 0);
6538 atomic_set(&t->trace_overrun, 0);
6539 t->curr_ret_stack = -1;
6540 /* Make sure the tasks see the -1 first: */
6542 t->ret_stack = ret_stack_list[start++];
6544 } while_each_thread(g, t);
6547 read_unlock(&tasklist_lock);
6549 for (i = start; i < end; i++)
6550 kfree(ret_stack_list[i]);
6555 ftrace_graph_probe_sched_switch(void *ignore, bool preempt,
6556 struct task_struct *prev, struct task_struct *next)
6558 unsigned long long timestamp;
6562 * Does the user want to count the time a function was asleep.
6563 * If so, do not update the time stamps.
6565 if (fgraph_sleep_time)
6568 timestamp = trace_clock_local();
6570 prev->ftrace_timestamp = timestamp;
6572 /* only process tasks that we timestamped */
6573 if (!next->ftrace_timestamp)
6577 * Update all the counters in next to make up for the
6578 * time next was sleeping.
6580 timestamp -= next->ftrace_timestamp;
6582 for (index = next->curr_ret_stack; index >= 0; index--)
6583 next->ret_stack[index].calltime += timestamp;
6586 /* Allocate a return stack for each task */
6587 static int start_graph_tracing(void)
6589 struct ftrace_ret_stack **ret_stack_list;
6592 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
6593 sizeof(struct ftrace_ret_stack *),
6596 if (!ret_stack_list)
6599 /* The cpu_boot init_task->ret_stack will never be freed */
6600 for_each_online_cpu(cpu) {
6601 if (!idle_task(cpu)->ret_stack)
6602 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
6606 ret = alloc_retstack_tasklist(ret_stack_list);
6607 } while (ret == -EAGAIN);
6610 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
6612 pr_info("ftrace_graph: Couldn't activate tracepoint"
6613 " probe to kernel_sched_switch\n");
6616 kfree(ret_stack_list);
6621 * Hibernation protection.
6622 * The state of the current task is too much unstable during
6623 * suspend/restore to disk. We want to protect against that.
6626 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
6630 case PM_HIBERNATION_PREPARE:
6631 pause_graph_tracing();
6634 case PM_POST_HIBERNATION:
6635 unpause_graph_tracing();
6641 static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
6643 if (!ftrace_ops_test(&global_ops, trace->func, NULL))
6645 return __ftrace_graph_entry(trace);
6649 * The function graph tracer should only trace the functions defined
6650 * by set_ftrace_filter and set_ftrace_notrace. If another function
6651 * tracer ops is registered, the graph tracer requires testing the
6652 * function against the global ops, and not just trace any function
6653 * that any ftrace_ops registered.
6655 static void update_function_graph_func(void)
6657 struct ftrace_ops *op;
6658 bool do_test = false;
6661 * The graph and global ops share the same set of functions
6662 * to test. If any other ops is on the list, then
6663 * the graph tracing needs to test if its the function
6666 do_for_each_ftrace_op(op, ftrace_ops_list) {
6667 if (op != &global_ops && op != &graph_ops &&
6668 op != &ftrace_list_end) {
6670 /* in double loop, break out with goto */
6673 } while_for_each_ftrace_op(op);
6676 ftrace_graph_entry = ftrace_graph_entry_test;
6678 ftrace_graph_entry = __ftrace_graph_entry;
6681 static struct notifier_block ftrace_suspend_notifier = {
6682 .notifier_call = ftrace_suspend_notifier_call,
6685 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
6686 trace_func_graph_ent_t entryfunc)
6690 mutex_lock(&ftrace_lock);
6692 /* we currently allow only one tracer registered at a time */
6693 if (ftrace_graph_active) {
6698 register_pm_notifier(&ftrace_suspend_notifier);
6700 ftrace_graph_active++;
6701 ret = start_graph_tracing();
6703 ftrace_graph_active--;
6707 ftrace_graph_return = retfunc;
6710 * Update the indirect function to the entryfunc, and the
6711 * function that gets called to the entry_test first. Then
6712 * call the update fgraph entry function to determine if
6713 * the entryfunc should be called directly or not.
6715 __ftrace_graph_entry = entryfunc;
6716 ftrace_graph_entry = ftrace_graph_entry_test;
6717 update_function_graph_func();
6719 ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET);
6721 mutex_unlock(&ftrace_lock);
6725 void unregister_ftrace_graph(void)
6727 mutex_lock(&ftrace_lock);
6729 if (unlikely(!ftrace_graph_active))
6732 ftrace_graph_active--;
6733 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
6734 ftrace_graph_entry = ftrace_graph_entry_stub;
6735 __ftrace_graph_entry = ftrace_graph_entry_stub;
6736 ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET);
6737 unregister_pm_notifier(&ftrace_suspend_notifier);
6738 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
6740 #ifdef CONFIG_DYNAMIC_FTRACE
6742 * Function graph does not allocate the trampoline, but
6743 * other global_ops do. We need to reset the ALLOC_TRAMP flag
6746 global_ops.trampoline = save_global_trampoline;
6747 if (save_global_flags & FTRACE_OPS_FL_ALLOC_TRAMP)
6748 global_ops.flags |= FTRACE_OPS_FL_ALLOC_TRAMP;
6752 mutex_unlock(&ftrace_lock);
6755 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
6758 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
6760 atomic_set(&t->tracing_graph_pause, 0);
6761 atomic_set(&t->trace_overrun, 0);
6762 t->ftrace_timestamp = 0;
6763 /* make curr_ret_stack visible before we add the ret_stack */
6765 t->ret_stack = ret_stack;
6769 * Allocate a return stack for the idle task. May be the first
6770 * time through, or it may be done by CPU hotplug online.
6772 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
6774 t->curr_ret_stack = -1;
6776 * The idle task has no parent, it either has its own
6777 * stack or no stack at all.
6780 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
6782 if (ftrace_graph_active) {
6783 struct ftrace_ret_stack *ret_stack;
6785 ret_stack = per_cpu(idle_ret_stack, cpu);
6787 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
6788 * sizeof(struct ftrace_ret_stack),
6792 per_cpu(idle_ret_stack, cpu) = ret_stack;
6794 graph_init_task(t, ret_stack);
6798 /* Allocate a return stack for newly created task */
6799 void ftrace_graph_init_task(struct task_struct *t)
6801 /* Make sure we do not use the parent ret_stack */
6802 t->ret_stack = NULL;
6803 t->curr_ret_stack = -1;
6805 if (ftrace_graph_active) {
6806 struct ftrace_ret_stack *ret_stack;
6808 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
6809 * sizeof(struct ftrace_ret_stack),
6813 graph_init_task(t, ret_stack);
6817 void ftrace_graph_exit_task(struct task_struct *t)
6819 struct ftrace_ret_stack *ret_stack = t->ret_stack;
6821 t->ret_stack = NULL;
6822 /* NULL must become visible to IRQs before we free it: */