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/kallsyms.h>
19 #include <linux/seq_file.h>
20 #include <linux/suspend.h>
21 #include <linux/tracefs.h>
22 #include <linux/hardirq.h>
23 #include <linux/kthread.h>
24 #include <linux/uaccess.h>
25 #include <linux/bsearch.h>
26 #include <linux/module.h>
27 #include <linux/ftrace.h>
28 #include <linux/sysctl.h>
29 #include <linux/slab.h>
30 #include <linux/ctype.h>
31 #include <linux/sort.h>
32 #include <linux/list.h>
33 #include <linux/hash.h>
34 #include <linux/rcupdate.h>
36 #include <trace/events/sched.h>
38 #include <asm/setup.h>
40 #include "trace_output.h"
41 #include "trace_stat.h"
43 #define FTRACE_WARN_ON(cond) \
51 #define FTRACE_WARN_ON_ONCE(cond) \
54 if (WARN_ON_ONCE(___r)) \
59 /* hash bits for specific function selection */
60 #define FTRACE_HASH_BITS 7
61 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
62 #define FTRACE_HASH_DEFAULT_BITS 10
63 #define FTRACE_HASH_MAX_BITS 12
65 #define FL_GLOBAL_CONTROL_MASK (FTRACE_OPS_FL_CONTROL)
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 /* List for set_ftrace_pid's pids. */
95 LIST_HEAD(ftrace_pids);
97 struct list_head list;
101 static bool ftrace_pids_enabled(void)
103 return !list_empty(&ftrace_pids);
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_control_list __read_mostly = &ftrace_list_end;
117 static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
118 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
119 static struct ftrace_ops global_ops;
120 static struct ftrace_ops control_ops;
122 static void ftrace_ops_recurs_func(unsigned long ip, unsigned long parent_ip,
123 struct ftrace_ops *op, struct pt_regs *regs);
125 #if ARCH_SUPPORTS_FTRACE_OPS
126 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
127 struct ftrace_ops *op, struct pt_regs *regs);
129 /* See comment below, where ftrace_ops_list_func is defined */
130 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
131 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
135 * Traverse the ftrace_global_list, invoking all entries. The reason that we
136 * can use rcu_dereference_raw_notrace() is that elements removed from this list
137 * are simply leaked, so there is no need to interact with a grace-period
138 * mechanism. The rcu_dereference_raw_notrace() calls are needed to handle
139 * concurrent insertions into the ftrace_global_list.
141 * Silly Alpha and silly pointer-speculation compiler optimizations!
143 #define do_for_each_ftrace_op(op, list) \
144 op = rcu_dereference_raw_notrace(list); \
148 * Optimized for just a single item in the list (as that is the normal case).
150 #define while_for_each_ftrace_op(op) \
151 while (likely(op = rcu_dereference_raw_notrace((op)->next)) && \
152 unlikely((op) != &ftrace_list_end))
154 static inline void ftrace_ops_init(struct ftrace_ops *ops)
156 #ifdef CONFIG_DYNAMIC_FTRACE
157 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
158 mutex_init(&ops->local_hash.regex_lock);
159 ops->func_hash = &ops->local_hash;
160 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
166 * ftrace_nr_registered_ops - return number of ops registered
168 * Returns the number of ftrace_ops registered and tracing functions
170 int ftrace_nr_registered_ops(void)
172 struct ftrace_ops *ops;
175 mutex_lock(&ftrace_lock);
177 for (ops = ftrace_ops_list;
178 ops != &ftrace_list_end; ops = ops->next)
181 mutex_unlock(&ftrace_lock);
186 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
187 struct ftrace_ops *op, struct pt_regs *regs)
189 if (!test_tsk_trace_trace(current))
192 op->saved_func(ip, parent_ip, op, regs);
196 * clear_ftrace_function - reset the ftrace function
198 * This NULLs the ftrace function and in essence stops
199 * tracing. There may be lag
201 void clear_ftrace_function(void)
203 ftrace_trace_function = ftrace_stub;
206 static void control_ops_disable_all(struct ftrace_ops *ops)
210 for_each_possible_cpu(cpu)
211 *per_cpu_ptr(ops->disabled, cpu) = 1;
214 static int control_ops_alloc(struct ftrace_ops *ops)
216 int __percpu *disabled;
218 disabled = alloc_percpu(int);
222 ops->disabled = disabled;
223 control_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 ops or we force list func,
260 * then it needs to call the list anyway.
262 if (ops->flags & FTRACE_OPS_FL_DYNAMIC || FTRACE_FORCE_LIST_FUNC)
263 return ftrace_ops_list_func;
265 return ftrace_ops_get_func(ops);
268 static void update_ftrace_function(void)
273 * Prepare the ftrace_ops that the arch callback will use.
274 * If there's only one ftrace_ops registered, the ftrace_ops_list
275 * will point to the ops we want.
277 set_function_trace_op = ftrace_ops_list;
279 /* If there's no ftrace_ops registered, just call the stub function */
280 if (ftrace_ops_list == &ftrace_list_end) {
284 * If we are at the end of the list and this ops is
285 * recursion safe and not dynamic and the arch supports passing ops,
286 * then have the mcount trampoline call the function directly.
288 } else if (ftrace_ops_list->next == &ftrace_list_end) {
289 func = ftrace_ops_get_list_func(ftrace_ops_list);
292 /* Just use the default ftrace_ops */
293 set_function_trace_op = &ftrace_list_end;
294 func = ftrace_ops_list_func;
297 update_function_graph_func();
299 /* If there's no change, then do nothing more here */
300 if (ftrace_trace_function == func)
304 * If we are using the list function, it doesn't care
305 * about the function_trace_ops.
307 if (func == ftrace_ops_list_func) {
308 ftrace_trace_function = func;
310 * Don't even bother setting function_trace_ops,
311 * it would be racy to do so anyway.
316 #ifndef CONFIG_DYNAMIC_FTRACE
318 * For static tracing, we need to be a bit more careful.
319 * The function change takes affect immediately. Thus,
320 * we need to coorditate the setting of the function_trace_ops
321 * with the setting of the ftrace_trace_function.
323 * Set the function to the list ops, which will call the
324 * function we want, albeit indirectly, but it handles the
325 * ftrace_ops and doesn't depend on function_trace_op.
327 ftrace_trace_function = ftrace_ops_list_func;
329 * Make sure all CPUs see this. Yes this is slow, but static
330 * tracing is slow and nasty to have enabled.
332 schedule_on_each_cpu(ftrace_sync);
333 /* Now all cpus are using the list ops. */
334 function_trace_op = set_function_trace_op;
335 /* Make sure the function_trace_op is visible on all CPUs */
337 /* Nasty way to force a rmb on all cpus */
338 smp_call_function(ftrace_sync_ipi, NULL, 1);
339 /* OK, we are all set to update the ftrace_trace_function now! */
340 #endif /* !CONFIG_DYNAMIC_FTRACE */
342 ftrace_trace_function = func;
345 int using_ftrace_ops_list_func(void)
347 return ftrace_trace_function == ftrace_ops_list_func;
350 static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
354 * We are entering ops into the list but another
355 * CPU might be walking that list. We need to make sure
356 * the ops->next pointer is valid before another CPU sees
357 * the ops pointer included into the list.
359 rcu_assign_pointer(*list, ops);
362 static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
364 struct ftrace_ops **p;
367 * If we are removing the last function, then simply point
368 * to the ftrace_stub.
370 if (*list == ops && ops->next == &ftrace_list_end) {
371 *list = &ftrace_list_end;
375 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
386 static void add_ftrace_list_ops(struct ftrace_ops **list,
387 struct ftrace_ops *main_ops,
388 struct ftrace_ops *ops)
390 int first = *list == &ftrace_list_end;
391 add_ftrace_ops(list, ops);
393 add_ftrace_ops(&ftrace_ops_list, main_ops);
396 static int remove_ftrace_list_ops(struct ftrace_ops **list,
397 struct ftrace_ops *main_ops,
398 struct ftrace_ops *ops)
400 int ret = remove_ftrace_ops(list, ops);
401 if (!ret && *list == &ftrace_list_end)
402 ret = remove_ftrace_ops(&ftrace_ops_list, main_ops);
406 static void ftrace_update_trampoline(struct ftrace_ops *ops);
408 static int __register_ftrace_function(struct ftrace_ops *ops)
410 if (ops->flags & FTRACE_OPS_FL_DELETED)
413 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
416 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
418 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
419 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
420 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
422 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
423 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
426 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
427 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
430 if (!core_kernel_data((unsigned long)ops))
431 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
433 if (ops->flags & FTRACE_OPS_FL_CONTROL) {
434 if (control_ops_alloc(ops))
436 add_ftrace_list_ops(&ftrace_control_list, &control_ops, ops);
437 /* The control_ops needs the trampoline update */
440 add_ftrace_ops(&ftrace_ops_list, ops);
442 /* Always save the function, and reset at unregistering */
443 ops->saved_func = ops->func;
445 if (ops->flags & FTRACE_OPS_FL_PID && ftrace_pids_enabled())
446 ops->func = ftrace_pid_func;
448 ftrace_update_trampoline(ops);
451 update_ftrace_function();
456 static int __unregister_ftrace_function(struct ftrace_ops *ops)
460 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
463 if (ops->flags & FTRACE_OPS_FL_CONTROL) {
464 ret = remove_ftrace_list_ops(&ftrace_control_list,
467 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
473 update_ftrace_function();
475 ops->func = ops->saved_func;
480 static void ftrace_update_pid_func(void)
482 bool enabled = ftrace_pids_enabled();
483 struct ftrace_ops *op;
485 /* Only do something if we are tracing something */
486 if (ftrace_trace_function == ftrace_stub)
489 do_for_each_ftrace_op(op, ftrace_ops_list) {
490 if (op->flags & FTRACE_OPS_FL_PID) {
491 op->func = enabled ? ftrace_pid_func :
493 ftrace_update_trampoline(op);
495 } while_for_each_ftrace_op(op);
497 update_ftrace_function();
500 #ifdef CONFIG_FUNCTION_PROFILER
501 struct ftrace_profile {
502 struct hlist_node node;
504 unsigned long counter;
505 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
506 unsigned long long time;
507 unsigned long long time_squared;
511 struct ftrace_profile_page {
512 struct ftrace_profile_page *next;
514 struct ftrace_profile records[];
517 struct ftrace_profile_stat {
519 struct hlist_head *hash;
520 struct ftrace_profile_page *pages;
521 struct ftrace_profile_page *start;
522 struct tracer_stat stat;
525 #define PROFILE_RECORDS_SIZE \
526 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
528 #define PROFILES_PER_PAGE \
529 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
531 static int ftrace_profile_enabled __read_mostly;
533 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
534 static DEFINE_MUTEX(ftrace_profile_lock);
536 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
538 #define FTRACE_PROFILE_HASH_BITS 10
539 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
542 function_stat_next(void *v, int idx)
544 struct ftrace_profile *rec = v;
545 struct ftrace_profile_page *pg;
547 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
553 if ((void *)rec >= (void *)&pg->records[pg->index]) {
557 rec = &pg->records[0];
565 static void *function_stat_start(struct tracer_stat *trace)
567 struct ftrace_profile_stat *stat =
568 container_of(trace, struct ftrace_profile_stat, stat);
570 if (!stat || !stat->start)
573 return function_stat_next(&stat->start->records[0], 0);
576 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
577 /* function graph compares on total time */
578 static int function_stat_cmp(void *p1, void *p2)
580 struct ftrace_profile *a = p1;
581 struct ftrace_profile *b = p2;
583 if (a->time < b->time)
585 if (a->time > b->time)
591 /* not function graph compares against hits */
592 static int function_stat_cmp(void *p1, void *p2)
594 struct ftrace_profile *a = p1;
595 struct ftrace_profile *b = p2;
597 if (a->counter < b->counter)
599 if (a->counter > b->counter)
606 static int function_stat_headers(struct seq_file *m)
608 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
609 seq_puts(m, " Function "
612 "--- ---- --- ---\n");
614 seq_puts(m, " Function Hit\n"
620 static int function_stat_show(struct seq_file *m, void *v)
622 struct ftrace_profile *rec = v;
623 char str[KSYM_SYMBOL_LEN];
625 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
626 static struct trace_seq s;
627 unsigned long long avg;
628 unsigned long long stddev;
630 mutex_lock(&ftrace_profile_lock);
632 /* we raced with function_profile_reset() */
633 if (unlikely(rec->counter == 0)) {
638 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
640 do_div(avg, rec->counter);
641 if (tracing_thresh && (avg < tracing_thresh))
645 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
646 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
648 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
651 /* Sample standard deviation (s^2) */
652 if (rec->counter <= 1)
656 * Apply Welford's method:
657 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
659 stddev = rec->counter * rec->time_squared -
660 rec->time * rec->time;
663 * Divide only 1000 for ns^2 -> us^2 conversion.
664 * trace_print_graph_duration will divide 1000 again.
666 do_div(stddev, rec->counter * (rec->counter - 1) * 1000);
670 trace_print_graph_duration(rec->time, &s);
671 trace_seq_puts(&s, " ");
672 trace_print_graph_duration(avg, &s);
673 trace_seq_puts(&s, " ");
674 trace_print_graph_duration(stddev, &s);
675 trace_print_seq(m, &s);
679 mutex_unlock(&ftrace_profile_lock);
684 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
686 struct ftrace_profile_page *pg;
688 pg = stat->pages = stat->start;
691 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
696 memset(stat->hash, 0,
697 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
700 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
702 struct ftrace_profile_page *pg;
707 /* If we already allocated, do nothing */
711 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
715 #ifdef CONFIG_DYNAMIC_FTRACE
716 functions = ftrace_update_tot_cnt;
719 * We do not know the number of functions that exist because
720 * dynamic tracing is what counts them. With past experience
721 * we have around 20K functions. That should be more than enough.
722 * It is highly unlikely we will execute every function in
728 pg = stat->start = stat->pages;
730 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
732 for (i = 1; i < pages; i++) {
733 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
744 unsigned long tmp = (unsigned long)pg;
756 static int ftrace_profile_init_cpu(int cpu)
758 struct ftrace_profile_stat *stat;
761 stat = &per_cpu(ftrace_profile_stats, cpu);
764 /* If the profile is already created, simply reset it */
765 ftrace_profile_reset(stat);
770 * We are profiling all functions, but usually only a few thousand
771 * functions are hit. We'll make a hash of 1024 items.
773 size = FTRACE_PROFILE_HASH_SIZE;
775 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
780 /* Preallocate the function profiling pages */
781 if (ftrace_profile_pages_init(stat) < 0) {
790 static int ftrace_profile_init(void)
795 for_each_possible_cpu(cpu) {
796 ret = ftrace_profile_init_cpu(cpu);
804 /* interrupts must be disabled */
805 static struct ftrace_profile *
806 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
808 struct ftrace_profile *rec;
809 struct hlist_head *hhd;
812 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
813 hhd = &stat->hash[key];
815 if (hlist_empty(hhd))
818 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
826 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
827 struct ftrace_profile *rec)
831 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
832 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
836 * The memory is already allocated, this simply finds a new record to use.
838 static struct ftrace_profile *
839 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
841 struct ftrace_profile *rec = NULL;
843 /* prevent recursion (from NMIs) */
844 if (atomic_inc_return(&stat->disabled) != 1)
848 * Try to find the function again since an NMI
849 * could have added it
851 rec = ftrace_find_profiled_func(stat, ip);
855 if (stat->pages->index == PROFILES_PER_PAGE) {
856 if (!stat->pages->next)
858 stat->pages = stat->pages->next;
861 rec = &stat->pages->records[stat->pages->index++];
863 ftrace_add_profile(stat, rec);
866 atomic_dec(&stat->disabled);
872 function_profile_call(unsigned long ip, unsigned long parent_ip,
873 struct ftrace_ops *ops, struct pt_regs *regs)
875 struct ftrace_profile_stat *stat;
876 struct ftrace_profile *rec;
879 if (!ftrace_profile_enabled)
882 local_irq_save(flags);
884 stat = this_cpu_ptr(&ftrace_profile_stats);
885 if (!stat->hash || !ftrace_profile_enabled)
888 rec = ftrace_find_profiled_func(stat, ip);
890 rec = ftrace_profile_alloc(stat, ip);
897 local_irq_restore(flags);
900 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
901 static int profile_graph_entry(struct ftrace_graph_ent *trace)
903 function_profile_call(trace->func, 0, NULL, NULL);
907 static void profile_graph_return(struct ftrace_graph_ret *trace)
909 struct ftrace_profile_stat *stat;
910 unsigned long long calltime;
911 struct ftrace_profile *rec;
914 local_irq_save(flags);
915 stat = this_cpu_ptr(&ftrace_profile_stats);
916 if (!stat->hash || !ftrace_profile_enabled)
919 /* If the calltime was zero'd ignore it */
920 if (!trace->calltime)
923 calltime = trace->rettime - trace->calltime;
925 if (!fgraph_graph_time) {
928 index = trace->depth;
930 /* Append this call time to the parent time to subtract */
932 current->ret_stack[index - 1].subtime += calltime;
934 if (current->ret_stack[index].subtime < calltime)
935 calltime -= current->ret_stack[index].subtime;
940 rec = ftrace_find_profiled_func(stat, trace->func);
942 rec->time += calltime;
943 rec->time_squared += calltime * calltime;
947 local_irq_restore(flags);
950 static int register_ftrace_profiler(void)
952 return register_ftrace_graph(&profile_graph_return,
953 &profile_graph_entry);
956 static void unregister_ftrace_profiler(void)
958 unregister_ftrace_graph();
961 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
962 .func = function_profile_call,
963 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
964 INIT_OPS_HASH(ftrace_profile_ops)
967 static int register_ftrace_profiler(void)
969 return register_ftrace_function(&ftrace_profile_ops);
972 static void unregister_ftrace_profiler(void)
974 unregister_ftrace_function(&ftrace_profile_ops);
976 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
979 ftrace_profile_write(struct file *filp, const char __user *ubuf,
980 size_t cnt, loff_t *ppos)
985 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
991 mutex_lock(&ftrace_profile_lock);
992 if (ftrace_profile_enabled ^ val) {
994 ret = ftrace_profile_init();
1000 ret = register_ftrace_profiler();
1005 ftrace_profile_enabled = 1;
1007 ftrace_profile_enabled = 0;
1009 * unregister_ftrace_profiler calls stop_machine
1010 * so this acts like an synchronize_sched.
1012 unregister_ftrace_profiler();
1016 mutex_unlock(&ftrace_profile_lock);
1024 ftrace_profile_read(struct file *filp, char __user *ubuf,
1025 size_t cnt, loff_t *ppos)
1027 char buf[64]; /* big enough to hold a number */
1030 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
1031 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1034 static const struct file_operations ftrace_profile_fops = {
1035 .open = tracing_open_generic,
1036 .read = ftrace_profile_read,
1037 .write = ftrace_profile_write,
1038 .llseek = default_llseek,
1041 /* used to initialize the real stat files */
1042 static struct tracer_stat function_stats __initdata = {
1043 .name = "functions",
1044 .stat_start = function_stat_start,
1045 .stat_next = function_stat_next,
1046 .stat_cmp = function_stat_cmp,
1047 .stat_headers = function_stat_headers,
1048 .stat_show = function_stat_show
1051 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1053 struct ftrace_profile_stat *stat;
1054 struct dentry *entry;
1059 for_each_possible_cpu(cpu) {
1060 stat = &per_cpu(ftrace_profile_stats, cpu);
1062 /* allocate enough for function name + cpu number */
1063 name = kmalloc(32, GFP_KERNEL);
1066 * The files created are permanent, if something happens
1067 * we still do not free memory.
1070 "Could not allocate stat file for cpu %d\n",
1074 stat->stat = function_stats;
1075 snprintf(name, 32, "function%d", cpu);
1076 stat->stat.name = name;
1077 ret = register_stat_tracer(&stat->stat);
1080 "Could not register function stat for cpu %d\n",
1087 entry = tracefs_create_file("function_profile_enabled", 0644,
1088 d_tracer, NULL, &ftrace_profile_fops);
1090 pr_warning("Could not create tracefs "
1091 "'function_profile_enabled' entry\n");
1094 #else /* CONFIG_FUNCTION_PROFILER */
1095 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1098 #endif /* CONFIG_FUNCTION_PROFILER */
1100 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1102 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1103 static int ftrace_graph_active;
1105 # define ftrace_graph_active 0
1108 #ifdef CONFIG_DYNAMIC_FTRACE
1110 static struct ftrace_ops *removed_ops;
1113 * Set when doing a global update, like enabling all recs or disabling them.
1114 * It is not set when just updating a single ftrace_ops.
1116 static bool update_all_ops;
1118 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1119 # error Dynamic ftrace depends on MCOUNT_RECORD
1122 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
1124 struct ftrace_func_probe {
1125 struct hlist_node node;
1126 struct ftrace_probe_ops *ops;
1127 unsigned long flags;
1130 struct list_head free_list;
1133 struct ftrace_func_entry {
1134 struct hlist_node hlist;
1138 struct ftrace_hash {
1139 unsigned long size_bits;
1140 struct hlist_head *buckets;
1141 unsigned long count;
1142 struct rcu_head rcu;
1146 * We make these constant because no one should touch them,
1147 * but they are used as the default "empty hash", to avoid allocating
1148 * it all the time. These are in a read only section such that if
1149 * anyone does try to modify it, it will cause an exception.
1151 static const struct hlist_head empty_buckets[1];
1152 static const struct ftrace_hash empty_hash = {
1153 .buckets = (struct hlist_head *)empty_buckets,
1155 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1157 static struct ftrace_ops global_ops = {
1158 .func = ftrace_stub,
1159 .local_hash.notrace_hash = EMPTY_HASH,
1160 .local_hash.filter_hash = EMPTY_HASH,
1161 INIT_OPS_HASH(global_ops)
1162 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
1163 FTRACE_OPS_FL_INITIALIZED |
1168 * This is used by __kernel_text_address() to return true if the
1169 * address is on a dynamically allocated trampoline that would
1170 * not return true for either core_kernel_text() or
1171 * is_module_text_address().
1173 bool is_ftrace_trampoline(unsigned long addr)
1175 struct ftrace_ops *op;
1179 * Some of the ops may be dynamically allocated,
1180 * they are freed after a synchronize_sched().
1182 preempt_disable_notrace();
1184 do_for_each_ftrace_op(op, ftrace_ops_list) {
1186 * This is to check for dynamically allocated trampolines.
1187 * Trampolines that are in kernel text will have
1188 * core_kernel_text() return true.
1190 if (op->trampoline && op->trampoline_size)
1191 if (addr >= op->trampoline &&
1192 addr < op->trampoline + op->trampoline_size) {
1196 } while_for_each_ftrace_op(op);
1199 preempt_enable_notrace();
1204 struct ftrace_page {
1205 struct ftrace_page *next;
1206 struct dyn_ftrace *records;
1211 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1212 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1214 /* estimate from running different kernels */
1215 #define NR_TO_INIT 10000
1217 static struct ftrace_page *ftrace_pages_start;
1218 static struct ftrace_page *ftrace_pages;
1220 static bool __always_inline ftrace_hash_empty(struct ftrace_hash *hash)
1222 return !hash || !hash->count;
1225 static struct ftrace_func_entry *
1226 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1229 struct ftrace_func_entry *entry;
1230 struct hlist_head *hhd;
1232 if (ftrace_hash_empty(hash))
1235 if (hash->size_bits > 0)
1236 key = hash_long(ip, hash->size_bits);
1240 hhd = &hash->buckets[key];
1242 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1243 if (entry->ip == ip)
1249 static void __add_hash_entry(struct ftrace_hash *hash,
1250 struct ftrace_func_entry *entry)
1252 struct hlist_head *hhd;
1255 if (hash->size_bits)
1256 key = hash_long(entry->ip, hash->size_bits);
1260 hhd = &hash->buckets[key];
1261 hlist_add_head(&entry->hlist, hhd);
1265 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1267 struct ftrace_func_entry *entry;
1269 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1274 __add_hash_entry(hash, entry);
1280 free_hash_entry(struct ftrace_hash *hash,
1281 struct ftrace_func_entry *entry)
1283 hlist_del(&entry->hlist);
1289 remove_hash_entry(struct ftrace_hash *hash,
1290 struct ftrace_func_entry *entry)
1292 hlist_del(&entry->hlist);
1296 static void ftrace_hash_clear(struct ftrace_hash *hash)
1298 struct hlist_head *hhd;
1299 struct hlist_node *tn;
1300 struct ftrace_func_entry *entry;
1301 int size = 1 << hash->size_bits;
1307 for (i = 0; i < size; i++) {
1308 hhd = &hash->buckets[i];
1309 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1310 free_hash_entry(hash, entry);
1312 FTRACE_WARN_ON(hash->count);
1315 static void free_ftrace_hash(struct ftrace_hash *hash)
1317 if (!hash || hash == EMPTY_HASH)
1319 ftrace_hash_clear(hash);
1320 kfree(hash->buckets);
1324 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1326 struct ftrace_hash *hash;
1328 hash = container_of(rcu, struct ftrace_hash, rcu);
1329 free_ftrace_hash(hash);
1332 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1334 if (!hash || hash == EMPTY_HASH)
1336 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1339 void ftrace_free_filter(struct ftrace_ops *ops)
1341 ftrace_ops_init(ops);
1342 free_ftrace_hash(ops->func_hash->filter_hash);
1343 free_ftrace_hash(ops->func_hash->notrace_hash);
1346 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1348 struct ftrace_hash *hash;
1351 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1355 size = 1 << size_bits;
1356 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1358 if (!hash->buckets) {
1363 hash->size_bits = size_bits;
1368 static struct ftrace_hash *
1369 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1371 struct ftrace_func_entry *entry;
1372 struct ftrace_hash *new_hash;
1377 new_hash = alloc_ftrace_hash(size_bits);
1382 if (ftrace_hash_empty(hash))
1385 size = 1 << hash->size_bits;
1386 for (i = 0; i < size; i++) {
1387 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1388 ret = add_hash_entry(new_hash, entry->ip);
1394 FTRACE_WARN_ON(new_hash->count != hash->count);
1399 free_ftrace_hash(new_hash);
1404 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1406 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1408 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1409 struct ftrace_hash *new_hash);
1412 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1413 struct ftrace_hash **dst, struct ftrace_hash *src)
1415 struct ftrace_func_entry *entry;
1416 struct hlist_node *tn;
1417 struct hlist_head *hhd;
1418 struct ftrace_hash *new_hash;
1419 int size = src->count;
1424 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1425 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1429 * If the new source is empty, just free dst and assign it
1433 new_hash = EMPTY_HASH;
1438 * Make the hash size about 1/2 the # found
1440 for (size /= 2; size; size >>= 1)
1443 /* Don't allocate too much */
1444 if (bits > FTRACE_HASH_MAX_BITS)
1445 bits = FTRACE_HASH_MAX_BITS;
1447 new_hash = alloc_ftrace_hash(bits);
1451 size = 1 << src->size_bits;
1452 for (i = 0; i < size; i++) {
1453 hhd = &src->buckets[i];
1454 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1455 remove_hash_entry(src, entry);
1456 __add_hash_entry(new_hash, entry);
1461 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1463 /* IPMODIFY should be updated only when filter_hash updating */
1464 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1466 free_ftrace_hash(new_hash);
1472 * Remove the current set, update the hash and add
1475 ftrace_hash_rec_disable_modify(ops, enable);
1477 rcu_assign_pointer(*dst, new_hash);
1479 ftrace_hash_rec_enable_modify(ops, enable);
1484 static bool hash_contains_ip(unsigned long ip,
1485 struct ftrace_ops_hash *hash)
1488 * The function record is a match if it exists in the filter
1489 * hash and not in the notrace hash. Note, an emty hash is
1490 * considered a match for the filter hash, but an empty
1491 * notrace hash is considered not in the notrace hash.
1493 return (ftrace_hash_empty(hash->filter_hash) ||
1494 ftrace_lookup_ip(hash->filter_hash, ip)) &&
1495 (ftrace_hash_empty(hash->notrace_hash) ||
1496 !ftrace_lookup_ip(hash->notrace_hash, ip));
1500 * Test the hashes for this ops to see if we want to call
1501 * the ops->func or not.
1503 * It's a match if the ip is in the ops->filter_hash or
1504 * the filter_hash does not exist or is empty,
1506 * the ip is not in the ops->notrace_hash.
1508 * This needs to be called with preemption disabled as
1509 * the hashes are freed with call_rcu_sched().
1512 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1514 struct ftrace_ops_hash hash;
1517 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1519 * There's a small race when adding ops that the ftrace handler
1520 * that wants regs, may be called without them. We can not
1521 * allow that handler to be called if regs is NULL.
1523 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1527 hash.filter_hash = rcu_dereference_raw_notrace(ops->func_hash->filter_hash);
1528 hash.notrace_hash = rcu_dereference_raw_notrace(ops->func_hash->notrace_hash);
1530 if (hash_contains_ip(ip, &hash))
1539 * This is a double for. Do not use 'break' to break out of the loop,
1540 * you must use a goto.
1542 #define do_for_each_ftrace_rec(pg, rec) \
1543 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1545 for (_____i = 0; _____i < pg->index; _____i++) { \
1546 rec = &pg->records[_____i];
1548 #define while_for_each_ftrace_rec() \
1553 static int ftrace_cmp_recs(const void *a, const void *b)
1555 const struct dyn_ftrace *key = a;
1556 const struct dyn_ftrace *rec = b;
1558 if (key->flags < rec->ip)
1560 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1565 static unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1567 struct ftrace_page *pg;
1568 struct dyn_ftrace *rec;
1569 struct dyn_ftrace key;
1572 key.flags = end; /* overload flags, as it is unsigned long */
1574 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1575 if (end < pg->records[0].ip ||
1576 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1578 rec = bsearch(&key, pg->records, pg->index,
1579 sizeof(struct dyn_ftrace),
1589 * ftrace_location - return true if the ip giving is a traced location
1590 * @ip: the instruction pointer to check
1592 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1593 * That is, the instruction that is either a NOP or call to
1594 * the function tracer. It checks the ftrace internal tables to
1595 * determine if the address belongs or not.
1597 unsigned long ftrace_location(unsigned long ip)
1599 return ftrace_location_range(ip, ip);
1603 * ftrace_text_reserved - return true if range contains an ftrace location
1604 * @start: start of range to search
1605 * @end: end of range to search (inclusive). @end points to the last byte to check.
1607 * Returns 1 if @start and @end contains a ftrace location.
1608 * That is, the instruction that is either a NOP or call to
1609 * the function tracer. It checks the ftrace internal tables to
1610 * determine if the address belongs or not.
1612 int ftrace_text_reserved(const void *start, const void *end)
1616 ret = ftrace_location_range((unsigned long)start,
1617 (unsigned long)end);
1622 /* Test if ops registered to this rec needs regs */
1623 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1625 struct ftrace_ops *ops;
1626 bool keep_regs = false;
1628 for (ops = ftrace_ops_list;
1629 ops != &ftrace_list_end; ops = ops->next) {
1630 /* pass rec in as regs to have non-NULL val */
1631 if (ftrace_ops_test(ops, rec->ip, rec)) {
1632 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1642 static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
1646 struct ftrace_hash *hash;
1647 struct ftrace_hash *other_hash;
1648 struct ftrace_page *pg;
1649 struct dyn_ftrace *rec;
1653 /* Only update if the ops has been registered */
1654 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1658 * In the filter_hash case:
1659 * If the count is zero, we update all records.
1660 * Otherwise we just update the items in the hash.
1662 * In the notrace_hash case:
1663 * We enable the update in the hash.
1664 * As disabling notrace means enabling the tracing,
1665 * and enabling notrace means disabling, the inc variable
1669 hash = ops->func_hash->filter_hash;
1670 other_hash = ops->func_hash->notrace_hash;
1671 if (ftrace_hash_empty(hash))
1675 hash = ops->func_hash->notrace_hash;
1676 other_hash = ops->func_hash->filter_hash;
1678 * If the notrace hash has no items,
1679 * then there's nothing to do.
1681 if (ftrace_hash_empty(hash))
1685 do_for_each_ftrace_rec(pg, rec) {
1686 int in_other_hash = 0;
1692 * Only the filter_hash affects all records.
1693 * Update if the record is not in the notrace hash.
1695 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1698 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1699 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1702 * If filter_hash is set, we want to match all functions
1703 * that are in the hash but not in the other hash.
1705 * If filter_hash is not set, then we are decrementing.
1706 * That means we match anything that is in the hash
1707 * and also in the other_hash. That is, we need to turn
1708 * off functions in the other hash because they are disabled
1711 if (filter_hash && in_hash && !in_other_hash)
1713 else if (!filter_hash && in_hash &&
1714 (in_other_hash || ftrace_hash_empty(other_hash)))
1722 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1726 * If there's only a single callback registered to a
1727 * function, and the ops has a trampoline registered
1728 * for it, then we can call it directly.
1730 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1731 rec->flags |= FTRACE_FL_TRAMP;
1734 * If we are adding another function callback
1735 * to this function, and the previous had a
1736 * custom trampoline in use, then we need to go
1737 * back to the default trampoline.
1739 rec->flags &= ~FTRACE_FL_TRAMP;
1742 * If any ops wants regs saved for this function
1743 * then all ops will get saved regs.
1745 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1746 rec->flags |= FTRACE_FL_REGS;
1748 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1753 * If the rec had REGS enabled and the ops that is
1754 * being removed had REGS set, then see if there is
1755 * still any ops for this record that wants regs.
1756 * If not, we can stop recording them.
1758 if (ftrace_rec_count(rec) > 0 &&
1759 rec->flags & FTRACE_FL_REGS &&
1760 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1761 if (!test_rec_ops_needs_regs(rec))
1762 rec->flags &= ~FTRACE_FL_REGS;
1766 * If the rec had TRAMP enabled, then it needs to
1767 * be cleared. As TRAMP can only be enabled iff
1768 * there is only a single ops attached to it.
1769 * In otherwords, always disable it on decrementing.
1770 * In the future, we may set it if rec count is
1771 * decremented to one, and the ops that is left
1774 rec->flags &= ~FTRACE_FL_TRAMP;
1777 * flags will be cleared in ftrace_check_record()
1778 * if rec count is zero.
1782 /* Shortcut, if we handled all records, we are done. */
1783 if (!all && count == hash->count)
1785 } while_for_each_ftrace_rec();
1788 static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
1791 __ftrace_hash_rec_update(ops, filter_hash, 0);
1794 static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
1797 __ftrace_hash_rec_update(ops, filter_hash, 1);
1800 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1801 int filter_hash, int inc)
1803 struct ftrace_ops *op;
1805 __ftrace_hash_rec_update(ops, filter_hash, inc);
1807 if (ops->func_hash != &global_ops.local_hash)
1811 * If the ops shares the global_ops hash, then we need to update
1812 * all ops that are enabled and use this hash.
1814 do_for_each_ftrace_op(op, ftrace_ops_list) {
1818 if (op->func_hash == &global_ops.local_hash)
1819 __ftrace_hash_rec_update(op, filter_hash, inc);
1820 } while_for_each_ftrace_op(op);
1823 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1826 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1829 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1832 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1836 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1837 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1838 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1839 * Note that old_hash and new_hash has below meanings
1840 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1841 * - If the hash is EMPTY_HASH, it hits nothing
1842 * - Anything else hits the recs which match the hash entries.
1844 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1845 struct ftrace_hash *old_hash,
1846 struct ftrace_hash *new_hash)
1848 struct ftrace_page *pg;
1849 struct dyn_ftrace *rec, *end = NULL;
1852 /* Only update if the ops has been registered */
1853 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1856 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1860 * Since the IPMODIFY is a very address sensitive action, we do not
1861 * allow ftrace_ops to set all functions to new hash.
1863 if (!new_hash || !old_hash)
1866 /* Update rec->flags */
1867 do_for_each_ftrace_rec(pg, rec) {
1868 /* We need to update only differences of filter_hash */
1869 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1870 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1871 if (in_old == in_new)
1875 /* New entries must ensure no others are using it */
1876 if (rec->flags & FTRACE_FL_IPMODIFY)
1878 rec->flags |= FTRACE_FL_IPMODIFY;
1879 } else /* Removed entry */
1880 rec->flags &= ~FTRACE_FL_IPMODIFY;
1881 } while_for_each_ftrace_rec();
1888 /* Roll back what we did above */
1889 do_for_each_ftrace_rec(pg, rec) {
1893 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1894 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1895 if (in_old == in_new)
1899 rec->flags &= ~FTRACE_FL_IPMODIFY;
1901 rec->flags |= FTRACE_FL_IPMODIFY;
1902 } while_for_each_ftrace_rec();
1908 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1910 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1912 if (ftrace_hash_empty(hash))
1915 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1918 /* Disabling always succeeds */
1919 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1921 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1923 if (ftrace_hash_empty(hash))
1926 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1929 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1930 struct ftrace_hash *new_hash)
1932 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1934 if (ftrace_hash_empty(old_hash))
1937 if (ftrace_hash_empty(new_hash))
1940 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
1943 static void print_ip_ins(const char *fmt, const unsigned char *p)
1947 printk(KERN_CONT "%s", fmt);
1949 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1950 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1953 static struct ftrace_ops *
1954 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1956 enum ftrace_bug_type ftrace_bug_type;
1957 const void *ftrace_expected;
1959 static void print_bug_type(void)
1961 switch (ftrace_bug_type) {
1962 case FTRACE_BUG_UNKNOWN:
1964 case FTRACE_BUG_INIT:
1965 pr_info("Initializing ftrace call sites\n");
1967 case FTRACE_BUG_NOP:
1968 pr_info("Setting ftrace call site to NOP\n");
1970 case FTRACE_BUG_CALL:
1971 pr_info("Setting ftrace call site to call ftrace function\n");
1973 case FTRACE_BUG_UPDATE:
1974 pr_info("Updating ftrace call site to call a different ftrace function\n");
1980 * ftrace_bug - report and shutdown function tracer
1981 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1982 * @rec: The record that failed
1984 * The arch code that enables or disables the function tracing
1985 * can call ftrace_bug() when it has detected a problem in
1986 * modifying the code. @failed should be one of either:
1987 * EFAULT - if the problem happens on reading the @ip address
1988 * EINVAL - if what is read at @ip is not what was expected
1989 * EPERM - if the problem happens on writting to the @ip address
1991 void ftrace_bug(int failed, struct dyn_ftrace *rec)
1993 unsigned long ip = rec ? rec->ip : 0;
1997 FTRACE_WARN_ON_ONCE(1);
1998 pr_info("ftrace faulted on modifying ");
2002 FTRACE_WARN_ON_ONCE(1);
2003 pr_info("ftrace failed to modify ");
2005 print_ip_ins(" actual: ", (unsigned char *)ip);
2007 if (ftrace_expected) {
2008 print_ip_ins(" expected: ", ftrace_expected);
2013 FTRACE_WARN_ON_ONCE(1);
2014 pr_info("ftrace faulted on writing ");
2018 FTRACE_WARN_ON_ONCE(1);
2019 pr_info("ftrace faulted on unknown error ");
2024 struct ftrace_ops *ops = NULL;
2026 pr_info("ftrace record flags: %lx\n", rec->flags);
2027 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2028 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2029 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2030 ops = ftrace_find_tramp_ops_any(rec);
2032 pr_cont("\ttramp: %pS",
2033 (void *)ops->trampoline);
2035 pr_cont("\ttramp: ERROR!");
2038 ip = ftrace_get_addr_curr(rec);
2039 pr_cont(" expected tramp: %lx\n", ip);
2043 static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
2045 unsigned long flag = 0UL;
2047 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2050 * If we are updating calls:
2052 * If the record has a ref count, then we need to enable it
2053 * because someone is using it.
2055 * Otherwise we make sure its disabled.
2057 * If we are disabling calls, then disable all records that
2060 if (enable && ftrace_rec_count(rec))
2061 flag = FTRACE_FL_ENABLED;
2064 * If enabling and the REGS flag does not match the REGS_EN, or
2065 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2066 * this record. Set flags to fail the compare against ENABLED.
2069 if (!(rec->flags & FTRACE_FL_REGS) !=
2070 !(rec->flags & FTRACE_FL_REGS_EN))
2071 flag |= FTRACE_FL_REGS;
2073 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2074 !(rec->flags & FTRACE_FL_TRAMP_EN))
2075 flag |= FTRACE_FL_TRAMP;
2078 /* If the state of this record hasn't changed, then do nothing */
2079 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2080 return FTRACE_UPDATE_IGNORE;
2083 /* Save off if rec is being enabled (for return value) */
2084 flag ^= rec->flags & FTRACE_FL_ENABLED;
2087 rec->flags |= FTRACE_FL_ENABLED;
2088 if (flag & FTRACE_FL_REGS) {
2089 if (rec->flags & FTRACE_FL_REGS)
2090 rec->flags |= FTRACE_FL_REGS_EN;
2092 rec->flags &= ~FTRACE_FL_REGS_EN;
2094 if (flag & FTRACE_FL_TRAMP) {
2095 if (rec->flags & FTRACE_FL_TRAMP)
2096 rec->flags |= FTRACE_FL_TRAMP_EN;
2098 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2103 * If this record is being updated from a nop, then
2104 * return UPDATE_MAKE_CALL.
2106 * return UPDATE_MODIFY_CALL to tell the caller to convert
2107 * from the save regs, to a non-save regs function or
2108 * vice versa, or from a trampoline call.
2110 if (flag & FTRACE_FL_ENABLED) {
2111 ftrace_bug_type = FTRACE_BUG_CALL;
2112 return FTRACE_UPDATE_MAKE_CALL;
2115 ftrace_bug_type = FTRACE_BUG_UPDATE;
2116 return FTRACE_UPDATE_MODIFY_CALL;
2120 /* If there's no more users, clear all flags */
2121 if (!ftrace_rec_count(rec))
2125 * Just disable the record, but keep the ops TRAMP
2126 * and REGS states. The _EN flags must be disabled though.
2128 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2132 ftrace_bug_type = FTRACE_BUG_NOP;
2133 return FTRACE_UPDATE_MAKE_NOP;
2137 * ftrace_update_record, set a record that now is tracing or not
2138 * @rec: the record to update
2139 * @enable: set to 1 if the record is tracing, zero to force disable
2141 * The records that represent all functions that can be traced need
2142 * to be updated when tracing has been enabled.
2144 int ftrace_update_record(struct dyn_ftrace *rec, int enable)
2146 return ftrace_check_record(rec, enable, 1);
2150 * ftrace_test_record, check if the record has been enabled or not
2151 * @rec: the record to test
2152 * @enable: set to 1 to check if enabled, 0 if it is disabled
2154 * The arch code may need to test if a record is already set to
2155 * tracing to determine how to modify the function code that it
2158 int ftrace_test_record(struct dyn_ftrace *rec, int enable)
2160 return ftrace_check_record(rec, enable, 0);
2163 static struct ftrace_ops *
2164 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2166 struct ftrace_ops *op;
2167 unsigned long ip = rec->ip;
2169 do_for_each_ftrace_op(op, ftrace_ops_list) {
2171 if (!op->trampoline)
2174 if (hash_contains_ip(ip, op->func_hash))
2176 } while_for_each_ftrace_op(op);
2181 static struct ftrace_ops *
2182 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2184 struct ftrace_ops *op;
2185 unsigned long ip = rec->ip;
2188 * Need to check removed ops first.
2189 * If they are being removed, and this rec has a tramp,
2190 * and this rec is in the ops list, then it would be the
2191 * one with the tramp.
2194 if (hash_contains_ip(ip, &removed_ops->old_hash))
2199 * Need to find the current trampoline for a rec.
2200 * Now, a trampoline is only attached to a rec if there
2201 * was a single 'ops' attached to it. But this can be called
2202 * when we are adding another op to the rec or removing the
2203 * current one. Thus, if the op is being added, we can
2204 * ignore it because it hasn't attached itself to the rec
2207 * If an ops is being modified (hooking to different functions)
2208 * then we don't care about the new functions that are being
2209 * added, just the old ones (that are probably being removed).
2211 * If we are adding an ops to a function that already is using
2212 * a trampoline, it needs to be removed (trampolines are only
2213 * for single ops connected), then an ops that is not being
2214 * modified also needs to be checked.
2216 do_for_each_ftrace_op(op, ftrace_ops_list) {
2218 if (!op->trampoline)
2222 * If the ops is being added, it hasn't gotten to
2223 * the point to be removed from this tree yet.
2225 if (op->flags & FTRACE_OPS_FL_ADDING)
2230 * If the ops is being modified and is in the old
2231 * hash, then it is probably being removed from this
2234 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2235 hash_contains_ip(ip, &op->old_hash))
2238 * If the ops is not being added or modified, and it's
2239 * in its normal filter hash, then this must be the one
2242 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2243 hash_contains_ip(ip, op->func_hash))
2246 } while_for_each_ftrace_op(op);
2251 static struct ftrace_ops *
2252 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2254 struct ftrace_ops *op;
2255 unsigned long ip = rec->ip;
2257 do_for_each_ftrace_op(op, ftrace_ops_list) {
2258 /* pass rec in as regs to have non-NULL val */
2259 if (hash_contains_ip(ip, op->func_hash))
2261 } while_for_each_ftrace_op(op);
2267 * ftrace_get_addr_new - Get the call address to set to
2268 * @rec: The ftrace record descriptor
2270 * If the record has the FTRACE_FL_REGS set, that means that it
2271 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2272 * is not not set, then it wants to convert to the normal callback.
2274 * Returns the address of the trampoline to set to
2276 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2278 struct ftrace_ops *ops;
2280 /* Trampolines take precedence over regs */
2281 if (rec->flags & FTRACE_FL_TRAMP) {
2282 ops = ftrace_find_tramp_ops_new(rec);
2283 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2284 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2285 (void *)rec->ip, (void *)rec->ip, rec->flags);
2286 /* Ftrace is shutting down, return anything */
2287 return (unsigned long)FTRACE_ADDR;
2289 return ops->trampoline;
2292 if (rec->flags & FTRACE_FL_REGS)
2293 return (unsigned long)FTRACE_REGS_ADDR;
2295 return (unsigned long)FTRACE_ADDR;
2299 * ftrace_get_addr_curr - Get the call address that is already there
2300 * @rec: The ftrace record descriptor
2302 * The FTRACE_FL_REGS_EN is set when the record already points to
2303 * a function that saves all the regs. Basically the '_EN' version
2304 * represents the current state of the function.
2306 * Returns the address of the trampoline that is currently being called
2308 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2310 struct ftrace_ops *ops;
2312 /* Trampolines take precedence over regs */
2313 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2314 ops = ftrace_find_tramp_ops_curr(rec);
2315 if (FTRACE_WARN_ON(!ops)) {
2316 pr_warning("Bad trampoline accounting at: %p (%pS)\n",
2317 (void *)rec->ip, (void *)rec->ip);
2318 /* Ftrace is shutting down, return anything */
2319 return (unsigned long)FTRACE_ADDR;
2321 return ops->trampoline;
2324 if (rec->flags & FTRACE_FL_REGS_EN)
2325 return (unsigned long)FTRACE_REGS_ADDR;
2327 return (unsigned long)FTRACE_ADDR;
2331 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
2333 unsigned long ftrace_old_addr;
2334 unsigned long ftrace_addr;
2337 ftrace_addr = ftrace_get_addr_new(rec);
2339 /* This needs to be done before we call ftrace_update_record */
2340 ftrace_old_addr = ftrace_get_addr_curr(rec);
2342 ret = ftrace_update_record(rec, enable);
2344 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2347 case FTRACE_UPDATE_IGNORE:
2350 case FTRACE_UPDATE_MAKE_CALL:
2351 ftrace_bug_type = FTRACE_BUG_CALL;
2352 return ftrace_make_call(rec, ftrace_addr);
2354 case FTRACE_UPDATE_MAKE_NOP:
2355 ftrace_bug_type = FTRACE_BUG_NOP;
2356 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2358 case FTRACE_UPDATE_MODIFY_CALL:
2359 ftrace_bug_type = FTRACE_BUG_UPDATE;
2360 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2363 return -1; /* unknow ftrace bug */
2366 void __weak ftrace_replace_code(int enable)
2368 struct dyn_ftrace *rec;
2369 struct ftrace_page *pg;
2372 if (unlikely(ftrace_disabled))
2375 do_for_each_ftrace_rec(pg, rec) {
2376 failed = __ftrace_replace_code(rec, enable);
2378 ftrace_bug(failed, rec);
2379 /* Stop processing */
2382 } while_for_each_ftrace_rec();
2385 struct ftrace_rec_iter {
2386 struct ftrace_page *pg;
2391 * ftrace_rec_iter_start, start up iterating over traced functions
2393 * Returns an iterator handle that is used to iterate over all
2394 * the records that represent address locations where functions
2397 * May return NULL if no records are available.
2399 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2402 * We only use a single iterator.
2403 * Protected by the ftrace_lock mutex.
2405 static struct ftrace_rec_iter ftrace_rec_iter;
2406 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2408 iter->pg = ftrace_pages_start;
2411 /* Could have empty pages */
2412 while (iter->pg && !iter->pg->index)
2413 iter->pg = iter->pg->next;
2422 * ftrace_rec_iter_next, get the next record to process.
2423 * @iter: The handle to the iterator.
2425 * Returns the next iterator after the given iterator @iter.
2427 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2431 if (iter->index >= iter->pg->index) {
2432 iter->pg = iter->pg->next;
2435 /* Could have empty pages */
2436 while (iter->pg && !iter->pg->index)
2437 iter->pg = iter->pg->next;
2447 * ftrace_rec_iter_record, get the record at the iterator location
2448 * @iter: The current iterator location
2450 * Returns the record that the current @iter is at.
2452 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2454 return &iter->pg->records[iter->index];
2458 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
2462 if (unlikely(ftrace_disabled))
2465 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
2467 ftrace_bug_type = FTRACE_BUG_INIT;
2468 ftrace_bug(ret, rec);
2475 * archs can override this function if they must do something
2476 * before the modifying code is performed.
2478 int __weak ftrace_arch_code_modify_prepare(void)
2484 * archs can override this function if they must do something
2485 * after the modifying code is performed.
2487 int __weak ftrace_arch_code_modify_post_process(void)
2492 void ftrace_modify_all_code(int command)
2494 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2498 * If the ftrace_caller calls a ftrace_ops func directly,
2499 * we need to make sure that it only traces functions it
2500 * expects to trace. When doing the switch of functions,
2501 * we need to update to the ftrace_ops_list_func first
2502 * before the transition between old and new calls are set,
2503 * as the ftrace_ops_list_func will check the ops hashes
2504 * to make sure the ops are having the right functions
2508 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2509 if (FTRACE_WARN_ON(err))
2513 if (command & FTRACE_UPDATE_CALLS)
2514 ftrace_replace_code(1);
2515 else if (command & FTRACE_DISABLE_CALLS)
2516 ftrace_replace_code(0);
2518 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2519 function_trace_op = set_function_trace_op;
2521 /* If irqs are disabled, we are in stop machine */
2522 if (!irqs_disabled())
2523 smp_call_function(ftrace_sync_ipi, NULL, 1);
2524 err = ftrace_update_ftrace_func(ftrace_trace_function);
2525 if (FTRACE_WARN_ON(err))
2529 if (command & FTRACE_START_FUNC_RET)
2530 err = ftrace_enable_ftrace_graph_caller();
2531 else if (command & FTRACE_STOP_FUNC_RET)
2532 err = ftrace_disable_ftrace_graph_caller();
2533 FTRACE_WARN_ON(err);
2536 static int __ftrace_modify_code(void *data)
2538 int *command = data;
2540 ftrace_modify_all_code(*command);
2546 * ftrace_run_stop_machine, go back to the stop machine method
2547 * @command: The command to tell ftrace what to do
2549 * If an arch needs to fall back to the stop machine method, the
2550 * it can call this function.
2552 void ftrace_run_stop_machine(int command)
2554 stop_machine(__ftrace_modify_code, &command, NULL);
2558 * arch_ftrace_update_code, modify the code to trace or not trace
2559 * @command: The command that needs to be done
2561 * Archs can override this function if it does not need to
2562 * run stop_machine() to modify code.
2564 void __weak arch_ftrace_update_code(int command)
2566 ftrace_run_stop_machine(command);
2569 static void ftrace_run_update_code(int command)
2573 ret = ftrace_arch_code_modify_prepare();
2574 FTRACE_WARN_ON(ret);
2579 * By default we use stop_machine() to modify the code.
2580 * But archs can do what ever they want as long as it
2581 * is safe. The stop_machine() is the safest, but also
2582 * produces the most overhead.
2584 arch_ftrace_update_code(command);
2586 ret = ftrace_arch_code_modify_post_process();
2587 FTRACE_WARN_ON(ret);
2590 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2591 struct ftrace_ops_hash *old_hash)
2593 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2594 ops->old_hash.filter_hash = old_hash->filter_hash;
2595 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2596 ftrace_run_update_code(command);
2597 ops->old_hash.filter_hash = NULL;
2598 ops->old_hash.notrace_hash = NULL;
2599 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2602 static ftrace_func_t saved_ftrace_func;
2603 static int ftrace_start_up;
2605 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2609 static void control_ops_free(struct ftrace_ops *ops)
2611 free_percpu(ops->disabled);
2614 static void ftrace_startup_enable(int command)
2616 if (saved_ftrace_func != ftrace_trace_function) {
2617 saved_ftrace_func = ftrace_trace_function;
2618 command |= FTRACE_UPDATE_TRACE_FUNC;
2621 if (!command || !ftrace_enabled)
2624 ftrace_run_update_code(command);
2627 static void ftrace_startup_all(int command)
2629 update_all_ops = true;
2630 ftrace_startup_enable(command);
2631 update_all_ops = false;
2634 static int ftrace_startup(struct ftrace_ops *ops, int command)
2638 if (unlikely(ftrace_disabled))
2641 ret = __register_ftrace_function(ops);
2646 command |= FTRACE_UPDATE_CALLS;
2649 * Note that ftrace probes uses this to start up
2650 * and modify functions it will probe. But we still
2651 * set the ADDING flag for modification, as probes
2652 * do not have trampolines. If they add them in the
2653 * future, then the probes will need to distinguish
2654 * between adding and updating probes.
2656 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2658 ret = ftrace_hash_ipmodify_enable(ops);
2660 /* Rollback registration process */
2661 __unregister_ftrace_function(ops);
2663 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2667 ftrace_hash_rec_enable(ops, 1);
2669 ftrace_startup_enable(command);
2671 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2676 static int ftrace_shutdown(struct ftrace_ops *ops, int command)
2680 if (unlikely(ftrace_disabled))
2683 ret = __unregister_ftrace_function(ops);
2689 * Just warn in case of unbalance, no need to kill ftrace, it's not
2690 * critical but the ftrace_call callers may be never nopped again after
2691 * further ftrace uses.
2693 WARN_ON_ONCE(ftrace_start_up < 0);
2695 /* Disabling ipmodify never fails */
2696 ftrace_hash_ipmodify_disable(ops);
2697 ftrace_hash_rec_disable(ops, 1);
2699 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2701 command |= FTRACE_UPDATE_CALLS;
2703 if (saved_ftrace_func != ftrace_trace_function) {
2704 saved_ftrace_func = ftrace_trace_function;
2705 command |= FTRACE_UPDATE_TRACE_FUNC;
2708 if (!command || !ftrace_enabled) {
2710 * If these are control ops, they still need their
2711 * per_cpu field freed. Since, function tracing is
2712 * not currently active, we can just free them
2713 * without synchronizing all CPUs.
2715 if (ops->flags & FTRACE_OPS_FL_CONTROL)
2716 control_ops_free(ops);
2721 * If the ops uses a trampoline, then it needs to be
2722 * tested first on update.
2724 ops->flags |= FTRACE_OPS_FL_REMOVING;
2727 /* The trampoline logic checks the old hashes */
2728 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2729 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2731 ftrace_run_update_code(command);
2734 * If there's no more ops registered with ftrace, run a
2735 * sanity check to make sure all rec flags are cleared.
2737 if (ftrace_ops_list == &ftrace_list_end) {
2738 struct ftrace_page *pg;
2739 struct dyn_ftrace *rec;
2741 do_for_each_ftrace_rec(pg, rec) {
2742 if (FTRACE_WARN_ON_ONCE(rec->flags))
2743 pr_warn(" %pS flags:%lx\n",
2744 (void *)rec->ip, rec->flags);
2745 } while_for_each_ftrace_rec();
2748 ops->old_hash.filter_hash = NULL;
2749 ops->old_hash.notrace_hash = NULL;
2752 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2755 * Dynamic ops may be freed, we must make sure that all
2756 * callers are done before leaving this function.
2757 * The same goes for freeing the per_cpu data of the control
2760 * Again, normal synchronize_sched() is not good enough.
2761 * We need to do a hard force of sched synchronization.
2762 * This is because we use preempt_disable() to do RCU, but
2763 * the function tracers can be called where RCU is not watching
2764 * (like before user_exit()). We can not rely on the RCU
2765 * infrastructure to do the synchronization, thus we must do it
2768 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_CONTROL)) {
2769 schedule_on_each_cpu(ftrace_sync);
2771 arch_ftrace_trampoline_free(ops);
2773 if (ops->flags & FTRACE_OPS_FL_CONTROL)
2774 control_ops_free(ops);
2780 static void ftrace_startup_sysctl(void)
2784 if (unlikely(ftrace_disabled))
2787 /* Force update next time */
2788 saved_ftrace_func = NULL;
2789 /* ftrace_start_up is true if we want ftrace running */
2790 if (ftrace_start_up) {
2791 command = FTRACE_UPDATE_CALLS;
2792 if (ftrace_graph_active)
2793 command |= FTRACE_START_FUNC_RET;
2794 ftrace_startup_enable(command);
2798 static void ftrace_shutdown_sysctl(void)
2802 if (unlikely(ftrace_disabled))
2805 /* ftrace_start_up is true if ftrace is running */
2806 if (ftrace_start_up) {
2807 command = FTRACE_DISABLE_CALLS;
2808 if (ftrace_graph_active)
2809 command |= FTRACE_STOP_FUNC_RET;
2810 ftrace_run_update_code(command);
2814 static cycle_t ftrace_update_time;
2815 unsigned long ftrace_update_tot_cnt;
2817 static inline int ops_traces_mod(struct ftrace_ops *ops)
2820 * Filter_hash being empty will default to trace module.
2821 * But notrace hash requires a test of individual module functions.
2823 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
2824 ftrace_hash_empty(ops->func_hash->notrace_hash);
2828 * Check if the current ops references the record.
2830 * If the ops traces all functions, then it was already accounted for.
2831 * If the ops does not trace the current record function, skip it.
2832 * If the ops ignores the function via notrace filter, skip it.
2835 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2837 /* If ops isn't enabled, ignore it */
2838 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2841 /* If ops traces all mods, we already accounted for it */
2842 if (ops_traces_mod(ops))
2845 /* The function must be in the filter */
2846 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
2847 !ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
2850 /* If in notrace hash, we ignore it too */
2851 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
2857 static int referenced_filters(struct dyn_ftrace *rec)
2859 struct ftrace_ops *ops;
2862 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
2863 if (ops_references_rec(ops, rec))
2870 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
2872 struct ftrace_page *pg;
2873 struct dyn_ftrace *p;
2874 cycle_t start, stop;
2875 unsigned long update_cnt = 0;
2876 unsigned long ref = 0;
2881 * When adding a module, we need to check if tracers are
2882 * currently enabled and if they are set to trace all functions.
2883 * If they are, we need to enable the module functions as well
2884 * as update the reference counts for those function records.
2887 struct ftrace_ops *ops;
2889 for (ops = ftrace_ops_list;
2890 ops != &ftrace_list_end; ops = ops->next) {
2891 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
2892 if (ops_traces_mod(ops))
2900 start = ftrace_now(raw_smp_processor_id());
2902 for (pg = new_pgs; pg; pg = pg->next) {
2904 for (i = 0; i < pg->index; i++) {
2907 /* If something went wrong, bail without enabling anything */
2908 if (unlikely(ftrace_disabled))
2911 p = &pg->records[i];
2913 cnt += referenced_filters(p);
2917 * Do the initial record conversion from mcount jump
2918 * to the NOP instructions.
2920 if (!ftrace_code_disable(mod, p))
2926 * If the tracing is enabled, go ahead and enable the record.
2928 * The reason not to enable the record immediatelly is the
2929 * inherent check of ftrace_make_nop/ftrace_make_call for
2930 * correct previous instructions. Making first the NOP
2931 * conversion puts the module to the correct state, thus
2932 * passing the ftrace_make_call check.
2934 if (ftrace_start_up && cnt) {
2935 int failed = __ftrace_replace_code(p, 1);
2937 ftrace_bug(failed, p);
2942 stop = ftrace_now(raw_smp_processor_id());
2943 ftrace_update_time = stop - start;
2944 ftrace_update_tot_cnt += update_cnt;
2949 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2954 if (WARN_ON(!count))
2957 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2960 * We want to fill as much as possible. No more than a page
2963 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2967 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2970 /* if we can't allocate this size, try something smaller */
2977 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2986 static struct ftrace_page *
2987 ftrace_allocate_pages(unsigned long num_to_init)
2989 struct ftrace_page *start_pg;
2990 struct ftrace_page *pg;
2997 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3002 * Try to allocate as much as possible in one continues
3003 * location that fills in all of the space. We want to
3004 * waste as little space as possible.
3007 cnt = ftrace_allocate_records(pg, num_to_init);
3015 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3027 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3028 free_pages((unsigned long)pg->records, order);
3029 start_pg = pg->next;
3033 pr_info("ftrace: FAILED to allocate memory for functions\n");
3037 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3039 struct ftrace_iterator {
3042 struct ftrace_page *pg;
3043 struct dyn_ftrace *func;
3044 struct ftrace_func_probe *probe;
3045 struct trace_parser parser;
3046 struct ftrace_hash *hash;
3047 struct ftrace_ops *ops;
3054 t_hash_next(struct seq_file *m, loff_t *pos)
3056 struct ftrace_iterator *iter = m->private;
3057 struct hlist_node *hnd = NULL;
3058 struct hlist_head *hhd;
3064 hnd = &iter->probe->node;
3066 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
3069 hhd = &ftrace_func_hash[iter->hidx];
3071 if (hlist_empty(hhd)) {
3087 if (WARN_ON_ONCE(!hnd))
3090 iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
3095 static void *t_hash_start(struct seq_file *m, loff_t *pos)
3097 struct ftrace_iterator *iter = m->private;
3101 if (!(iter->flags & FTRACE_ITER_DO_HASH))
3104 if (iter->func_pos > *pos)
3108 for (l = 0; l <= (*pos - iter->func_pos); ) {
3109 p = t_hash_next(m, &l);
3116 /* Only set this if we have an item */
3117 iter->flags |= FTRACE_ITER_HASH;
3123 t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
3125 struct ftrace_func_probe *rec;
3128 if (WARN_ON_ONCE(!rec))
3131 if (rec->ops->print)
3132 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
3134 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
3137 seq_printf(m, ":%p", rec->data);
3144 t_next(struct seq_file *m, void *v, loff_t *pos)
3146 struct ftrace_iterator *iter = m->private;
3147 struct ftrace_ops *ops = iter->ops;
3148 struct dyn_ftrace *rec = NULL;
3150 if (unlikely(ftrace_disabled))
3153 if (iter->flags & FTRACE_ITER_HASH)
3154 return t_hash_next(m, pos);
3157 iter->pos = iter->func_pos = *pos;
3159 if (iter->flags & FTRACE_ITER_PRINTALL)
3160 return t_hash_start(m, pos);
3163 if (iter->idx >= iter->pg->index) {
3164 if (iter->pg->next) {
3165 iter->pg = iter->pg->next;
3170 rec = &iter->pg->records[iter->idx++];
3171 if (((iter->flags & FTRACE_ITER_FILTER) &&
3172 !(ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))) ||
3174 ((iter->flags & FTRACE_ITER_NOTRACE) &&
3175 !ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip)) ||
3177 ((iter->flags & FTRACE_ITER_ENABLED) &&
3178 !(rec->flags & FTRACE_FL_ENABLED))) {
3186 return t_hash_start(m, pos);
3193 static void reset_iter_read(struct ftrace_iterator *iter)
3197 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_HASH);
3200 static void *t_start(struct seq_file *m, loff_t *pos)
3202 struct ftrace_iterator *iter = m->private;
3203 struct ftrace_ops *ops = iter->ops;
3207 mutex_lock(&ftrace_lock);
3209 if (unlikely(ftrace_disabled))
3213 * If an lseek was done, then reset and start from beginning.
3215 if (*pos < iter->pos)
3216 reset_iter_read(iter);
3219 * For set_ftrace_filter reading, if we have the filter
3220 * off, we can short cut and just print out that all
3221 * functions are enabled.
3223 if ((iter->flags & FTRACE_ITER_FILTER &&
3224 ftrace_hash_empty(ops->func_hash->filter_hash)) ||
3225 (iter->flags & FTRACE_ITER_NOTRACE &&
3226 ftrace_hash_empty(ops->func_hash->notrace_hash))) {
3228 return t_hash_start(m, pos);
3229 iter->flags |= FTRACE_ITER_PRINTALL;
3230 /* reset in case of seek/pread */
3231 iter->flags &= ~FTRACE_ITER_HASH;
3235 if (iter->flags & FTRACE_ITER_HASH)
3236 return t_hash_start(m, pos);
3239 * Unfortunately, we need to restart at ftrace_pages_start
3240 * every time we let go of the ftrace_mutex. This is because
3241 * those pointers can change without the lock.
3243 iter->pg = ftrace_pages_start;
3245 for (l = 0; l <= *pos; ) {
3246 p = t_next(m, p, &l);
3252 return t_hash_start(m, pos);
3257 static void t_stop(struct seq_file *m, void *p)
3259 mutex_unlock(&ftrace_lock);
3263 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3268 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3269 struct dyn_ftrace *rec)
3273 ptr = arch_ftrace_trampoline_func(ops, rec);
3275 seq_printf(m, " ->%pS", ptr);
3278 static int t_show(struct seq_file *m, void *v)
3280 struct ftrace_iterator *iter = m->private;
3281 struct dyn_ftrace *rec;
3283 if (iter->flags & FTRACE_ITER_HASH)
3284 return t_hash_show(m, iter);
3286 if (iter->flags & FTRACE_ITER_PRINTALL) {
3287 if (iter->flags & FTRACE_ITER_NOTRACE)
3288 seq_puts(m, "#### no functions disabled ####\n");
3290 seq_puts(m, "#### all functions enabled ####\n");
3299 seq_printf(m, "%ps", (void *)rec->ip);
3300 if (iter->flags & FTRACE_ITER_ENABLED) {
3301 struct ftrace_ops *ops = NULL;
3303 seq_printf(m, " (%ld)%s%s",
3304 ftrace_rec_count(rec),
3305 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3306 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ");
3307 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3308 ops = ftrace_find_tramp_ops_any(rec);
3310 seq_printf(m, "\ttramp: %pS",
3311 (void *)ops->trampoline);
3313 seq_puts(m, "\ttramp: ERROR!");
3316 add_trampoline_func(m, ops, rec);
3324 static const struct seq_operations show_ftrace_seq_ops = {
3332 ftrace_avail_open(struct inode *inode, struct file *file)
3334 struct ftrace_iterator *iter;
3336 if (unlikely(ftrace_disabled))
3339 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3341 iter->pg = ftrace_pages_start;
3342 iter->ops = &global_ops;
3345 return iter ? 0 : -ENOMEM;
3349 ftrace_enabled_open(struct inode *inode, struct file *file)
3351 struct ftrace_iterator *iter;
3353 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3355 iter->pg = ftrace_pages_start;
3356 iter->flags = FTRACE_ITER_ENABLED;
3357 iter->ops = &global_ops;
3360 return iter ? 0 : -ENOMEM;
3364 * ftrace_regex_open - initialize function tracer filter files
3365 * @ops: The ftrace_ops that hold the hash filters
3366 * @flag: The type of filter to process
3367 * @inode: The inode, usually passed in to your open routine
3368 * @file: The file, usually passed in to your open routine
3370 * ftrace_regex_open() initializes the filter files for the
3371 * @ops. Depending on @flag it may process the filter hash or
3372 * the notrace hash of @ops. With this called from the open
3373 * routine, you can use ftrace_filter_write() for the write
3374 * routine if @flag has FTRACE_ITER_FILTER set, or
3375 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3376 * tracing_lseek() should be used as the lseek routine, and
3377 * release must call ftrace_regex_release().
3380 ftrace_regex_open(struct ftrace_ops *ops, int flag,
3381 struct inode *inode, struct file *file)
3383 struct ftrace_iterator *iter;
3384 struct ftrace_hash *hash;
3387 ftrace_ops_init(ops);
3389 if (unlikely(ftrace_disabled))
3392 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3396 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
3404 mutex_lock(&ops->func_hash->regex_lock);
3406 if (flag & FTRACE_ITER_NOTRACE)
3407 hash = ops->func_hash->notrace_hash;
3409 hash = ops->func_hash->filter_hash;
3411 if (file->f_mode & FMODE_WRITE) {
3412 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3414 if (file->f_flags & O_TRUNC)
3415 iter->hash = alloc_ftrace_hash(size_bits);
3417 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3420 trace_parser_put(&iter->parser);
3427 if (file->f_mode & FMODE_READ) {
3428 iter->pg = ftrace_pages_start;
3430 ret = seq_open(file, &show_ftrace_seq_ops);
3432 struct seq_file *m = file->private_data;
3436 free_ftrace_hash(iter->hash);
3437 trace_parser_put(&iter->parser);
3441 file->private_data = iter;
3444 mutex_unlock(&ops->func_hash->regex_lock);
3450 ftrace_filter_open(struct inode *inode, struct file *file)
3452 struct ftrace_ops *ops = inode->i_private;
3454 return ftrace_regex_open(ops,
3455 FTRACE_ITER_FILTER | FTRACE_ITER_DO_HASH,
3460 ftrace_notrace_open(struct inode *inode, struct file *file)
3462 struct ftrace_ops *ops = inode->i_private;
3464 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3468 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3469 struct ftrace_glob {
3475 static int ftrace_match(char *str, struct ftrace_glob *g)
3482 if (strcmp(str, g->search) == 0)
3485 case MATCH_FRONT_ONLY:
3486 if (strncmp(str, g->search, g->len) == 0)
3489 case MATCH_MIDDLE_ONLY:
3490 if (strstr(str, g->search))
3493 case MATCH_END_ONLY:
3495 if (slen >= g->len &&
3496 memcmp(str + slen - g->len, g->search, g->len) == 0)
3505 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3507 struct ftrace_func_entry *entry;
3510 entry = ftrace_lookup_ip(hash, rec->ip);
3512 /* Do nothing if it doesn't exist */
3516 free_hash_entry(hash, entry);
3518 /* Do nothing if it exists */
3522 ret = add_hash_entry(hash, rec->ip);
3528 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3529 struct ftrace_glob *mod_g, int exclude_mod)
3531 char str[KSYM_SYMBOL_LEN];
3534 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3537 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3539 /* blank module name to match all modules */
3541 /* blank module globbing: modname xor exclude_mod */
3542 if ((!exclude_mod) != (!modname))
3547 /* not matching the module */
3548 if (!modname || !mod_matches) {
3555 if (mod_matches && exclude_mod)
3559 /* blank search means to match all funcs in the mod */
3564 return ftrace_match(str, func_g);
3568 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
3570 struct ftrace_page *pg;
3571 struct dyn_ftrace *rec;
3572 struct ftrace_glob func_g = { .type = MATCH_FULL };
3573 struct ftrace_glob mod_g = { .type = MATCH_FULL };
3574 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
3575 int exclude_mod = 0;
3581 func_g.type = filter_parse_regex(func, len, &func_g.search,
3583 func_g.len = strlen(func_g.search);
3587 mod_g.type = filter_parse_regex(mod, strlen(mod),
3588 &mod_g.search, &exclude_mod);
3589 mod_g.len = strlen(mod_g.search);
3592 mutex_lock(&ftrace_lock);
3594 if (unlikely(ftrace_disabled))
3597 do_for_each_ftrace_rec(pg, rec) {
3598 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
3599 ret = enter_record(hash, rec, clear_filter);
3606 } while_for_each_ftrace_rec();
3608 mutex_unlock(&ftrace_lock);
3614 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
3616 return match_records(hash, buff, len, NULL);
3621 * We register the module command as a template to show others how
3622 * to register the a command as well.
3626 ftrace_mod_callback(struct ftrace_hash *hash,
3627 char *func, char *cmd, char *module, int enable)
3632 * cmd == 'mod' because we only registered this func
3633 * for the 'mod' ftrace_func_command.
3634 * But if you register one func with multiple commands,
3635 * you can tell which command was used by the cmd
3638 ret = match_records(hash, func, strlen(func), module);
3646 static struct ftrace_func_command ftrace_mod_cmd = {
3648 .func = ftrace_mod_callback,
3651 static int __init ftrace_mod_cmd_init(void)
3653 return register_ftrace_command(&ftrace_mod_cmd);
3655 core_initcall(ftrace_mod_cmd_init);
3657 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
3658 struct ftrace_ops *op, struct pt_regs *pt_regs)
3660 struct ftrace_func_probe *entry;
3661 struct hlist_head *hhd;
3664 key = hash_long(ip, FTRACE_HASH_BITS);
3666 hhd = &ftrace_func_hash[key];
3668 if (hlist_empty(hhd))
3672 * Disable preemption for these calls to prevent a RCU grace
3673 * period. This syncs the hash iteration and freeing of items
3674 * on the hash. rcu_read_lock is too dangerous here.
3676 preempt_disable_notrace();
3677 hlist_for_each_entry_rcu_notrace(entry, hhd, node) {
3678 if (entry->ip == ip)
3679 entry->ops->func(ip, parent_ip, &entry->data);
3681 preempt_enable_notrace();
3684 static struct ftrace_ops trace_probe_ops __read_mostly =
3686 .func = function_trace_probe_call,
3687 .flags = FTRACE_OPS_FL_INITIALIZED,
3688 INIT_OPS_HASH(trace_probe_ops)
3691 static int ftrace_probe_registered;
3693 static void __enable_ftrace_function_probe(struct ftrace_ops_hash *old_hash)
3698 if (ftrace_probe_registered) {
3699 /* still need to update the function call sites */
3701 ftrace_run_modify_code(&trace_probe_ops, FTRACE_UPDATE_CALLS,
3706 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3707 struct hlist_head *hhd = &ftrace_func_hash[i];
3711 /* Nothing registered? */
3712 if (i == FTRACE_FUNC_HASHSIZE)
3715 ret = ftrace_startup(&trace_probe_ops, 0);
3717 ftrace_probe_registered = 1;
3720 static void __disable_ftrace_function_probe(void)
3724 if (!ftrace_probe_registered)
3727 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3728 struct hlist_head *hhd = &ftrace_func_hash[i];
3733 /* no more funcs left */
3734 ftrace_shutdown(&trace_probe_ops, 0);
3736 ftrace_probe_registered = 0;
3740 static void ftrace_free_entry(struct ftrace_func_probe *entry)
3742 if (entry->ops->free)
3743 entry->ops->free(entry->ops, entry->ip, &entry->data);
3748 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3751 struct ftrace_ops_hash old_hash_ops;
3752 struct ftrace_func_probe *entry;
3753 struct ftrace_glob func_g;
3754 struct ftrace_hash **orig_hash = &trace_probe_ops.func_hash->filter_hash;
3755 struct ftrace_hash *old_hash = *orig_hash;
3756 struct ftrace_hash *hash;
3757 struct ftrace_page *pg;
3758 struct dyn_ftrace *rec;
3764 func_g.type = filter_parse_regex(glob, strlen(glob),
3765 &func_g.search, ¬);
3766 func_g.len = strlen(func_g.search);
3768 /* we do not support '!' for function probes */
3772 mutex_lock(&trace_probe_ops.func_hash->regex_lock);
3774 old_hash_ops.filter_hash = old_hash;
3775 /* Probes only have filters */
3776 old_hash_ops.notrace_hash = NULL;
3778 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
3784 if (unlikely(ftrace_disabled)) {
3789 mutex_lock(&ftrace_lock);
3791 do_for_each_ftrace_rec(pg, rec) {
3793 if (!ftrace_match_record(rec, &func_g, NULL, 0))
3796 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
3798 /* If we did not process any, then return error */
3809 * The caller might want to do something special
3810 * for each function we find. We call the callback
3811 * to give the caller an opportunity to do so.
3814 if (ops->init(ops, rec->ip, &entry->data) < 0) {
3815 /* caller does not like this func */
3821 ret = enter_record(hash, rec, 0);
3829 entry->ip = rec->ip;
3831 key = hash_long(entry->ip, FTRACE_HASH_BITS);
3832 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
3834 } while_for_each_ftrace_rec();
3836 ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3838 __enable_ftrace_function_probe(&old_hash_ops);
3841 free_ftrace_hash_rcu(old_hash);
3846 mutex_unlock(&ftrace_lock);
3848 mutex_unlock(&trace_probe_ops.func_hash->regex_lock);
3849 free_ftrace_hash(hash);
3855 PROBE_TEST_FUNC = 1,
3860 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3861 void *data, int flags)
3863 struct ftrace_func_entry *rec_entry;
3864 struct ftrace_func_probe *entry;
3865 struct ftrace_func_probe *p;
3866 struct ftrace_glob func_g;
3867 struct ftrace_hash **orig_hash = &trace_probe_ops.func_hash->filter_hash;
3868 struct ftrace_hash *old_hash = *orig_hash;
3869 struct list_head free_list;
3870 struct ftrace_hash *hash;
3871 struct hlist_node *tmp;
3872 char str[KSYM_SYMBOL_LEN];
3875 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
3876 func_g.search = NULL;
3880 func_g.type = filter_parse_regex(glob, strlen(glob),
3881 &func_g.search, ¬);
3882 func_g.len = strlen(func_g.search);
3883 func_g.search = glob;
3885 /* we do not support '!' for function probes */
3890 mutex_lock(&trace_probe_ops.func_hash->regex_lock);
3892 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3894 /* Hmm, should report this somehow */
3897 INIT_LIST_HEAD(&free_list);
3899 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3900 struct hlist_head *hhd = &ftrace_func_hash[i];
3902 hlist_for_each_entry_safe(entry, tmp, hhd, node) {
3904 /* break up if statements for readability */
3905 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
3908 if ((flags & PROBE_TEST_DATA) && entry->data != data)
3911 /* do this last, since it is the most expensive */
3912 if (func_g.search) {
3913 kallsyms_lookup(entry->ip, NULL, NULL,
3915 if (!ftrace_match(str, &func_g))
3919 rec_entry = ftrace_lookup_ip(hash, entry->ip);
3920 /* It is possible more than one entry had this ip */
3922 free_hash_entry(hash, rec_entry);
3924 hlist_del_rcu(&entry->node);
3925 list_add(&entry->free_list, &free_list);
3928 mutex_lock(&ftrace_lock);
3929 __disable_ftrace_function_probe();
3931 * Remove after the disable is called. Otherwise, if the last
3932 * probe is removed, a null hash means *all enabled*.
3934 ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3935 synchronize_sched();
3937 free_ftrace_hash_rcu(old_hash);
3939 list_for_each_entry_safe(entry, p, &free_list, free_list) {
3940 list_del(&entry->free_list);
3941 ftrace_free_entry(entry);
3943 mutex_unlock(&ftrace_lock);
3946 mutex_unlock(&trace_probe_ops.func_hash->regex_lock);
3947 free_ftrace_hash(hash);
3951 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3954 __unregister_ftrace_function_probe(glob, ops, data,
3955 PROBE_TEST_FUNC | PROBE_TEST_DATA);
3959 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
3961 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
3964 void unregister_ftrace_function_probe_all(char *glob)
3966 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
3969 static LIST_HEAD(ftrace_commands);
3970 static DEFINE_MUTEX(ftrace_cmd_mutex);
3973 * Currently we only register ftrace commands from __init, so mark this
3976 __init int register_ftrace_command(struct ftrace_func_command *cmd)
3978 struct ftrace_func_command *p;
3981 mutex_lock(&ftrace_cmd_mutex);
3982 list_for_each_entry(p, &ftrace_commands, list) {
3983 if (strcmp(cmd->name, p->name) == 0) {
3988 list_add(&cmd->list, &ftrace_commands);
3990 mutex_unlock(&ftrace_cmd_mutex);
3996 * Currently we only unregister ftrace commands from __init, so mark
3999 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4001 struct ftrace_func_command *p, *n;
4004 mutex_lock(&ftrace_cmd_mutex);
4005 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4006 if (strcmp(cmd->name, p->name) == 0) {
4008 list_del_init(&p->list);
4013 mutex_unlock(&ftrace_cmd_mutex);
4018 static int ftrace_process_regex(struct ftrace_hash *hash,
4019 char *buff, int len, int enable)
4021 char *func, *command, *next = buff;
4022 struct ftrace_func_command *p;
4025 func = strsep(&next, ":");
4028 ret = ftrace_match_records(hash, func, len);
4038 command = strsep(&next, ":");
4040 mutex_lock(&ftrace_cmd_mutex);
4041 list_for_each_entry(p, &ftrace_commands, list) {
4042 if (strcmp(p->name, command) == 0) {
4043 ret = p->func(hash, func, command, next, enable);
4048 mutex_unlock(&ftrace_cmd_mutex);
4054 ftrace_regex_write(struct file *file, const char __user *ubuf,
4055 size_t cnt, loff_t *ppos, int enable)
4057 struct ftrace_iterator *iter;
4058 struct trace_parser *parser;
4064 if (file->f_mode & FMODE_READ) {
4065 struct seq_file *m = file->private_data;
4068 iter = file->private_data;
4070 if (unlikely(ftrace_disabled))
4073 /* iter->hash is a local copy, so we don't need regex_lock */
4075 parser = &iter->parser;
4076 read = trace_get_user(parser, ubuf, cnt, ppos);
4078 if (read >= 0 && trace_parser_loaded(parser) &&
4079 !trace_parser_cont(parser)) {
4080 ret = ftrace_process_regex(iter->hash, parser->buffer,
4081 parser->idx, enable);
4082 trace_parser_clear(parser);
4093 ftrace_filter_write(struct file *file, const char __user *ubuf,
4094 size_t cnt, loff_t *ppos)
4096 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4100 ftrace_notrace_write(struct file *file, const char __user *ubuf,
4101 size_t cnt, loff_t *ppos)
4103 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4107 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4109 struct ftrace_func_entry *entry;
4111 if (!ftrace_location(ip))
4115 entry = ftrace_lookup_ip(hash, ip);
4118 free_hash_entry(hash, entry);
4122 return add_hash_entry(hash, ip);
4125 static void ftrace_ops_update_code(struct ftrace_ops *ops,
4126 struct ftrace_ops_hash *old_hash)
4128 struct ftrace_ops *op;
4130 if (!ftrace_enabled)
4133 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4134 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4139 * If this is the shared global_ops filter, then we need to
4140 * check if there is another ops that shares it, is enabled.
4141 * If so, we still need to run the modify code.
4143 if (ops->func_hash != &global_ops.local_hash)
4146 do_for_each_ftrace_op(op, ftrace_ops_list) {
4147 if (op->func_hash == &global_ops.local_hash &&
4148 op->flags & FTRACE_OPS_FL_ENABLED) {
4149 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4150 /* Only need to do this once */
4153 } while_for_each_ftrace_op(op);
4157 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4158 unsigned long ip, int remove, int reset, int enable)
4160 struct ftrace_hash **orig_hash;
4161 struct ftrace_ops_hash old_hash_ops;
4162 struct ftrace_hash *old_hash;
4163 struct ftrace_hash *hash;
4166 if (unlikely(ftrace_disabled))
4169 mutex_lock(&ops->func_hash->regex_lock);
4172 orig_hash = &ops->func_hash->filter_hash;
4174 orig_hash = &ops->func_hash->notrace_hash;
4177 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4179 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4183 goto out_regex_unlock;
4186 if (buf && !ftrace_match_records(hash, buf, len)) {
4188 goto out_regex_unlock;
4191 ret = ftrace_match_addr(hash, ip, remove);
4193 goto out_regex_unlock;
4196 mutex_lock(&ftrace_lock);
4197 old_hash = *orig_hash;
4198 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4199 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4200 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4202 ftrace_ops_update_code(ops, &old_hash_ops);
4203 free_ftrace_hash_rcu(old_hash);
4205 mutex_unlock(&ftrace_lock);
4208 mutex_unlock(&ops->func_hash->regex_lock);
4210 free_ftrace_hash(hash);
4215 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
4216 int reset, int enable)
4218 return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
4222 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
4223 * @ops - the ops to set the filter with
4224 * @ip - the address to add to or remove from the filter.
4225 * @remove - non zero to remove the ip from the filter
4226 * @reset - non zero to reset all filters before applying this filter.
4228 * Filters denote which functions should be enabled when tracing is enabled
4229 * If @ip is NULL, it failes to update filter.
4231 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
4232 int remove, int reset)
4234 ftrace_ops_init(ops);
4235 return ftrace_set_addr(ops, ip, remove, reset, 1);
4237 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
4240 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4241 int reset, int enable)
4243 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
4247 * ftrace_set_filter - set a function to filter on in ftrace
4248 * @ops - the ops to set the filter with
4249 * @buf - the string that holds the function filter text.
4250 * @len - the length of the string.
4251 * @reset - non zero to reset all filters before applying this filter.
4253 * Filters denote which functions should be enabled when tracing is enabled.
4254 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4256 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
4259 ftrace_ops_init(ops);
4260 return ftrace_set_regex(ops, buf, len, reset, 1);
4262 EXPORT_SYMBOL_GPL(ftrace_set_filter);
4265 * ftrace_set_notrace - set a function to not trace in ftrace
4266 * @ops - the ops to set the notrace filter with
4267 * @buf - the string that holds the function notrace text.
4268 * @len - the length of the string.
4269 * @reset - non zero to reset all filters before applying this filter.
4271 * Notrace Filters denote which functions should not be enabled when tracing
4272 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4275 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
4278 ftrace_ops_init(ops);
4279 return ftrace_set_regex(ops, buf, len, reset, 0);
4281 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
4283 * ftrace_set_global_filter - set a function to filter on with global tracers
4284 * @buf - the string that holds the function filter text.
4285 * @len - the length of the string.
4286 * @reset - non zero to reset all filters before applying this filter.
4288 * Filters denote which functions should be enabled when tracing is enabled.
4289 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4291 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
4293 ftrace_set_regex(&global_ops, buf, len, reset, 1);
4295 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
4298 * ftrace_set_global_notrace - set a function to not trace with global tracers
4299 * @buf - the string that holds the function notrace text.
4300 * @len - the length of the string.
4301 * @reset - non zero to reset all filters before applying this filter.
4303 * Notrace Filters denote which functions should not be enabled when tracing
4304 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4307 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
4309 ftrace_set_regex(&global_ops, buf, len, reset, 0);
4311 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
4314 * command line interface to allow users to set filters on boot up.
4316 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
4317 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4318 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
4320 /* Used by function selftest to not test if filter is set */
4321 bool ftrace_filter_param __initdata;
4323 static int __init set_ftrace_notrace(char *str)
4325 ftrace_filter_param = true;
4326 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
4329 __setup("ftrace_notrace=", set_ftrace_notrace);
4331 static int __init set_ftrace_filter(char *str)
4333 ftrace_filter_param = true;
4334 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
4337 __setup("ftrace_filter=", set_ftrace_filter);
4339 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4340 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
4341 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4342 static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer);
4344 static unsigned long save_global_trampoline;
4345 static unsigned long save_global_flags;
4347 static int __init set_graph_function(char *str)
4349 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
4352 __setup("ftrace_graph_filter=", set_graph_function);
4354 static int __init set_graph_notrace_function(char *str)
4356 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
4359 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
4361 static void __init set_ftrace_early_graph(char *buf, int enable)
4365 unsigned long *table = ftrace_graph_funcs;
4366 int *count = &ftrace_graph_count;
4369 table = ftrace_graph_notrace_funcs;
4370 count = &ftrace_graph_notrace_count;
4374 func = strsep(&buf, ",");
4375 /* we allow only one expression at a time */
4376 ret = ftrace_set_func(table, count, FTRACE_GRAPH_MAX_FUNCS, func);
4378 printk(KERN_DEBUG "ftrace: function %s not "
4379 "traceable\n", func);
4382 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4385 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
4389 ftrace_ops_init(ops);
4392 func = strsep(&buf, ",");
4393 ftrace_set_regex(ops, func, strlen(func), 0, enable);
4397 static void __init set_ftrace_early_filters(void)
4399 if (ftrace_filter_buf[0])
4400 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
4401 if (ftrace_notrace_buf[0])
4402 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
4403 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4404 if (ftrace_graph_buf[0])
4405 set_ftrace_early_graph(ftrace_graph_buf, 1);
4406 if (ftrace_graph_notrace_buf[0])
4407 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
4408 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4411 int ftrace_regex_release(struct inode *inode, struct file *file)
4413 struct seq_file *m = (struct seq_file *)file->private_data;
4414 struct ftrace_ops_hash old_hash_ops;
4415 struct ftrace_iterator *iter;
4416 struct ftrace_hash **orig_hash;
4417 struct ftrace_hash *old_hash;
4418 struct trace_parser *parser;
4422 if (file->f_mode & FMODE_READ) {
4424 seq_release(inode, file);
4426 iter = file->private_data;
4428 parser = &iter->parser;
4429 if (trace_parser_loaded(parser)) {
4430 parser->buffer[parser->idx] = 0;
4431 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
4434 trace_parser_put(parser);
4436 mutex_lock(&iter->ops->func_hash->regex_lock);
4438 if (file->f_mode & FMODE_WRITE) {
4439 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
4442 orig_hash = &iter->ops->func_hash->filter_hash;
4444 orig_hash = &iter->ops->func_hash->notrace_hash;
4446 mutex_lock(&ftrace_lock);
4447 old_hash = *orig_hash;
4448 old_hash_ops.filter_hash = iter->ops->func_hash->filter_hash;
4449 old_hash_ops.notrace_hash = iter->ops->func_hash->notrace_hash;
4450 ret = ftrace_hash_move(iter->ops, filter_hash,
4451 orig_hash, iter->hash);
4453 ftrace_ops_update_code(iter->ops, &old_hash_ops);
4454 free_ftrace_hash_rcu(old_hash);
4456 mutex_unlock(&ftrace_lock);
4459 mutex_unlock(&iter->ops->func_hash->regex_lock);
4460 free_ftrace_hash(iter->hash);
4466 static const struct file_operations ftrace_avail_fops = {
4467 .open = ftrace_avail_open,
4469 .llseek = seq_lseek,
4470 .release = seq_release_private,
4473 static const struct file_operations ftrace_enabled_fops = {
4474 .open = ftrace_enabled_open,
4476 .llseek = seq_lseek,
4477 .release = seq_release_private,
4480 static const struct file_operations ftrace_filter_fops = {
4481 .open = ftrace_filter_open,
4483 .write = ftrace_filter_write,
4484 .llseek = tracing_lseek,
4485 .release = ftrace_regex_release,
4488 static const struct file_operations ftrace_notrace_fops = {
4489 .open = ftrace_notrace_open,
4491 .write = ftrace_notrace_write,
4492 .llseek = tracing_lseek,
4493 .release = ftrace_regex_release,
4496 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4498 static DEFINE_MUTEX(graph_lock);
4500 int ftrace_graph_count;
4501 int ftrace_graph_notrace_count;
4502 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
4503 unsigned long ftrace_graph_notrace_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
4505 struct ftrace_graph_data {
4506 unsigned long *table;
4509 const struct seq_operations *seq_ops;
4513 __g_next(struct seq_file *m, loff_t *pos)
4515 struct ftrace_graph_data *fgd = m->private;
4517 if (*pos >= *fgd->count)
4519 return &fgd->table[*pos];
4523 g_next(struct seq_file *m, void *v, loff_t *pos)
4526 return __g_next(m, pos);
4529 static void *g_start(struct seq_file *m, loff_t *pos)
4531 struct ftrace_graph_data *fgd = m->private;
4533 mutex_lock(&graph_lock);
4535 /* Nothing, tell g_show to print all functions are enabled */
4536 if (!*fgd->count && !*pos)
4539 return __g_next(m, pos);
4542 static void g_stop(struct seq_file *m, void *p)
4544 mutex_unlock(&graph_lock);
4547 static int g_show(struct seq_file *m, void *v)
4549 unsigned long *ptr = v;
4554 if (ptr == (unsigned long *)1) {
4555 struct ftrace_graph_data *fgd = m->private;
4557 if (fgd->table == ftrace_graph_funcs)
4558 seq_puts(m, "#### all functions enabled ####\n");
4560 seq_puts(m, "#### no functions disabled ####\n");
4564 seq_printf(m, "%ps\n", (void *)*ptr);
4569 static const struct seq_operations ftrace_graph_seq_ops = {
4577 __ftrace_graph_open(struct inode *inode, struct file *file,
4578 struct ftrace_graph_data *fgd)
4582 mutex_lock(&graph_lock);
4583 if ((file->f_mode & FMODE_WRITE) &&
4584 (file->f_flags & O_TRUNC)) {
4586 memset(fgd->table, 0, fgd->size * sizeof(*fgd->table));
4588 mutex_unlock(&graph_lock);
4590 if (file->f_mode & FMODE_READ) {
4591 ret = seq_open(file, fgd->seq_ops);
4593 struct seq_file *m = file->private_data;
4597 file->private_data = fgd;
4603 ftrace_graph_open(struct inode *inode, struct file *file)
4605 struct ftrace_graph_data *fgd;
4607 if (unlikely(ftrace_disabled))
4610 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
4614 fgd->table = ftrace_graph_funcs;
4615 fgd->size = FTRACE_GRAPH_MAX_FUNCS;
4616 fgd->count = &ftrace_graph_count;
4617 fgd->seq_ops = &ftrace_graph_seq_ops;
4619 return __ftrace_graph_open(inode, file, fgd);
4623 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
4625 struct ftrace_graph_data *fgd;
4627 if (unlikely(ftrace_disabled))
4630 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
4634 fgd->table = ftrace_graph_notrace_funcs;
4635 fgd->size = FTRACE_GRAPH_MAX_FUNCS;
4636 fgd->count = &ftrace_graph_notrace_count;
4637 fgd->seq_ops = &ftrace_graph_seq_ops;
4639 return __ftrace_graph_open(inode, file, fgd);
4643 ftrace_graph_release(struct inode *inode, struct file *file)
4645 if (file->f_mode & FMODE_READ) {
4646 struct seq_file *m = file->private_data;
4649 seq_release(inode, file);
4651 kfree(file->private_data);
4658 ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer)
4660 struct ftrace_glob func_g;
4661 struct dyn_ftrace *rec;
4662 struct ftrace_page *pg;
4669 func_g.type = filter_parse_regex(buffer, strlen(buffer),
4670 &func_g.search, ¬);
4671 if (!not && *idx >= size)
4674 func_g.len = strlen(func_g.search);
4676 mutex_lock(&ftrace_lock);
4678 if (unlikely(ftrace_disabled)) {
4679 mutex_unlock(&ftrace_lock);
4683 do_for_each_ftrace_rec(pg, rec) {
4685 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
4686 /* if it is in the array */
4688 for (i = 0; i < *idx; i++) {
4689 if (array[i] == rec->ip) {
4698 array[(*idx)++] = rec->ip;
4704 array[i] = array[--(*idx)];
4710 } while_for_each_ftrace_rec();
4712 mutex_unlock(&ftrace_lock);
4721 ftrace_graph_write(struct file *file, const char __user *ubuf,
4722 size_t cnt, loff_t *ppos)
4724 struct trace_parser parser;
4725 ssize_t read, ret = 0;
4726 struct ftrace_graph_data *fgd = file->private_data;
4731 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX))
4734 read = trace_get_user(&parser, ubuf, cnt, ppos);
4736 if (read >= 0 && trace_parser_loaded((&parser))) {
4737 parser.buffer[parser.idx] = 0;
4739 mutex_lock(&graph_lock);
4741 /* we allow only one expression at a time */
4742 ret = ftrace_set_func(fgd->table, fgd->count, fgd->size,
4745 mutex_unlock(&graph_lock);
4751 trace_parser_put(&parser);
4756 static const struct file_operations ftrace_graph_fops = {
4757 .open = ftrace_graph_open,
4759 .write = ftrace_graph_write,
4760 .llseek = tracing_lseek,
4761 .release = ftrace_graph_release,
4764 static const struct file_operations ftrace_graph_notrace_fops = {
4765 .open = ftrace_graph_notrace_open,
4767 .write = ftrace_graph_write,
4768 .llseek = tracing_lseek,
4769 .release = ftrace_graph_release,
4771 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4773 void ftrace_create_filter_files(struct ftrace_ops *ops,
4774 struct dentry *parent)
4777 trace_create_file("set_ftrace_filter", 0644, parent,
4778 ops, &ftrace_filter_fops);
4780 trace_create_file("set_ftrace_notrace", 0644, parent,
4781 ops, &ftrace_notrace_fops);
4785 * The name "destroy_filter_files" is really a misnomer. Although
4786 * in the future, it may actualy delete the files, but this is
4787 * really intended to make sure the ops passed in are disabled
4788 * and that when this function returns, the caller is free to
4791 * The "destroy" name is only to match the "create" name that this
4792 * should be paired with.
4794 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
4796 mutex_lock(&ftrace_lock);
4797 if (ops->flags & FTRACE_OPS_FL_ENABLED)
4798 ftrace_shutdown(ops, 0);
4799 ops->flags |= FTRACE_OPS_FL_DELETED;
4800 mutex_unlock(&ftrace_lock);
4803 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
4806 trace_create_file("available_filter_functions", 0444,
4807 d_tracer, NULL, &ftrace_avail_fops);
4809 trace_create_file("enabled_functions", 0444,
4810 d_tracer, NULL, &ftrace_enabled_fops);
4812 ftrace_create_filter_files(&global_ops, d_tracer);
4814 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4815 trace_create_file("set_graph_function", 0444, d_tracer,
4817 &ftrace_graph_fops);
4818 trace_create_file("set_graph_notrace", 0444, d_tracer,
4820 &ftrace_graph_notrace_fops);
4821 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4826 static int ftrace_cmp_ips(const void *a, const void *b)
4828 const unsigned long *ipa = a;
4829 const unsigned long *ipb = b;
4838 static int ftrace_process_locs(struct module *mod,
4839 unsigned long *start,
4842 struct ftrace_page *start_pg;
4843 struct ftrace_page *pg;
4844 struct dyn_ftrace *rec;
4845 unsigned long count;
4848 unsigned long flags = 0; /* Shut up gcc */
4851 count = end - start;
4856 sort(start, count, sizeof(*start),
4857 ftrace_cmp_ips, NULL);
4859 start_pg = ftrace_allocate_pages(count);
4863 mutex_lock(&ftrace_lock);
4866 * Core and each module needs their own pages, as
4867 * modules will free them when they are removed.
4868 * Force a new page to be allocated for modules.
4871 WARN_ON(ftrace_pages || ftrace_pages_start);
4872 /* First initialization */
4873 ftrace_pages = ftrace_pages_start = start_pg;
4878 if (WARN_ON(ftrace_pages->next)) {
4879 /* Hmm, we have free pages? */
4880 while (ftrace_pages->next)
4881 ftrace_pages = ftrace_pages->next;
4884 ftrace_pages->next = start_pg;
4890 addr = ftrace_call_adjust(*p++);
4892 * Some architecture linkers will pad between
4893 * the different mcount_loc sections of different
4894 * object files to satisfy alignments.
4895 * Skip any NULL pointers.
4900 if (pg->index == pg->size) {
4901 /* We should have allocated enough */
4902 if (WARN_ON(!pg->next))
4907 rec = &pg->records[pg->index++];
4911 /* We should have used all pages */
4914 /* Assign the last page to ftrace_pages */
4918 * We only need to disable interrupts on start up
4919 * because we are modifying code that an interrupt
4920 * may execute, and the modification is not atomic.
4921 * But for modules, nothing runs the code we modify
4922 * until we are finished with it, and there's no
4923 * reason to cause large interrupt latencies while we do it.
4926 local_irq_save(flags);
4927 ftrace_update_code(mod, start_pg);
4929 local_irq_restore(flags);
4932 mutex_unlock(&ftrace_lock);
4937 #ifdef CONFIG_MODULES
4939 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
4941 void ftrace_release_mod(struct module *mod)
4943 struct dyn_ftrace *rec;
4944 struct ftrace_page **last_pg;
4945 struct ftrace_page *pg;
4948 mutex_lock(&ftrace_lock);
4950 if (ftrace_disabled)
4954 * Each module has its own ftrace_pages, remove
4955 * them from the list.
4957 last_pg = &ftrace_pages_start;
4958 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
4959 rec = &pg->records[0];
4960 if (within_module_core(rec->ip, mod)) {
4962 * As core pages are first, the first
4963 * page should never be a module page.
4965 if (WARN_ON(pg == ftrace_pages_start))
4968 /* Check if we are deleting the last page */
4969 if (pg == ftrace_pages)
4970 ftrace_pages = next_to_ftrace_page(last_pg);
4972 *last_pg = pg->next;
4973 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
4974 free_pages((unsigned long)pg->records, order);
4977 last_pg = &pg->next;
4980 mutex_unlock(&ftrace_lock);
4983 static void ftrace_init_module(struct module *mod,
4984 unsigned long *start, unsigned long *end)
4986 if (ftrace_disabled || start == end)
4988 ftrace_process_locs(mod, start, end);
4991 void ftrace_module_init(struct module *mod)
4993 ftrace_init_module(mod, mod->ftrace_callsites,
4994 mod->ftrace_callsites +
4995 mod->num_ftrace_callsites);
4998 static int ftrace_module_notify_exit(struct notifier_block *self,
4999 unsigned long val, void *data)
5001 struct module *mod = data;
5003 if (val == MODULE_STATE_GOING)
5004 ftrace_release_mod(mod);
5009 static int ftrace_module_notify_exit(struct notifier_block *self,
5010 unsigned long val, void *data)
5014 #endif /* CONFIG_MODULES */
5016 struct notifier_block ftrace_module_exit_nb = {
5017 .notifier_call = ftrace_module_notify_exit,
5018 .priority = INT_MIN, /* Run after anything that can remove kprobes */
5021 void __init ftrace_init(void)
5023 extern unsigned long __start_mcount_loc[];
5024 extern unsigned long __stop_mcount_loc[];
5025 unsigned long count, flags;
5028 local_irq_save(flags);
5029 ret = ftrace_dyn_arch_init();
5030 local_irq_restore(flags);
5034 count = __stop_mcount_loc - __start_mcount_loc;
5036 pr_info("ftrace: No functions to be traced?\n");
5040 pr_info("ftrace: allocating %ld entries in %ld pages\n",
5041 count, count / ENTRIES_PER_PAGE + 1);
5043 last_ftrace_enabled = ftrace_enabled = 1;
5045 ret = ftrace_process_locs(NULL,
5049 ret = register_module_notifier(&ftrace_module_exit_nb);
5051 pr_warning("Failed to register trace ftrace module exit notifier\n");
5053 set_ftrace_early_filters();
5057 ftrace_disabled = 1;
5060 /* Do nothing if arch does not support this */
5061 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
5065 static void ftrace_update_trampoline(struct ftrace_ops *ops)
5069 * Currently there's no safe way to free a trampoline when the kernel
5070 * is configured with PREEMPT. That is because a task could be preempted
5071 * when it jumped to the trampoline, it may be preempted for a long time
5072 * depending on the system load, and currently there's no way to know
5073 * when it will be off the trampoline. If the trampoline is freed
5074 * too early, when the task runs again, it will be executing on freed
5077 #ifdef CONFIG_PREEMPT
5078 /* Currently, only non dynamic ops can have a trampoline */
5079 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
5083 arch_ftrace_update_trampoline(ops);
5088 static struct ftrace_ops global_ops = {
5089 .func = ftrace_stub,
5090 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
5091 FTRACE_OPS_FL_INITIALIZED |
5095 static int __init ftrace_nodyn_init(void)
5100 core_initcall(ftrace_nodyn_init);
5102 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
5103 static inline void ftrace_startup_enable(int command) { }
5104 static inline void ftrace_startup_all(int command) { }
5105 /* Keep as macros so we do not need to define the commands */
5106 # define ftrace_startup(ops, command) \
5108 int ___ret = __register_ftrace_function(ops); \
5110 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
5113 # define ftrace_shutdown(ops, command) \
5115 int ___ret = __unregister_ftrace_function(ops); \
5117 (ops)->flags &= ~FTRACE_OPS_FL_ENABLED; \
5121 # define ftrace_startup_sysctl() do { } while (0)
5122 # define ftrace_shutdown_sysctl() do { } while (0)
5125 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
5130 static void ftrace_update_trampoline(struct ftrace_ops *ops)
5134 #endif /* CONFIG_DYNAMIC_FTRACE */
5136 __init void ftrace_init_global_array_ops(struct trace_array *tr)
5138 tr->ops = &global_ops;
5139 tr->ops->private = tr;
5142 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
5144 /* If we filter on pids, update to use the pid function */
5145 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
5146 if (WARN_ON(tr->ops->func != ftrace_stub))
5147 printk("ftrace ops had %pS for function\n",
5150 tr->ops->func = func;
5151 tr->ops->private = tr;
5154 void ftrace_reset_array_ops(struct trace_array *tr)
5156 tr->ops->func = ftrace_stub;
5160 ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
5161 struct ftrace_ops *op, struct pt_regs *regs)
5163 if (unlikely(trace_recursion_test(TRACE_CONTROL_BIT)))
5167 * Some of the ops may be dynamically allocated,
5168 * they must be freed after a synchronize_sched().
5170 preempt_disable_notrace();
5171 trace_recursion_set(TRACE_CONTROL_BIT);
5174 * Control funcs (perf) uses RCU. Only trace if
5175 * RCU is currently active.
5177 if (!rcu_is_watching())
5180 do_for_each_ftrace_op(op, ftrace_control_list) {
5181 if (!(op->flags & FTRACE_OPS_FL_STUB) &&
5182 !ftrace_function_local_disabled(op) &&
5183 ftrace_ops_test(op, ip, regs))
5184 op->func(ip, parent_ip, op, regs);
5185 } while_for_each_ftrace_op(op);
5187 trace_recursion_clear(TRACE_CONTROL_BIT);
5188 preempt_enable_notrace();
5191 static struct ftrace_ops control_ops = {
5192 .func = ftrace_ops_control_func,
5193 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
5194 INIT_OPS_HASH(control_ops)
5198 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
5199 struct ftrace_ops *ignored, struct pt_regs *regs)
5201 struct ftrace_ops *op;
5204 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
5209 * Some of the ops may be dynamically allocated,
5210 * they must be freed after a synchronize_sched().
5212 preempt_disable_notrace();
5213 do_for_each_ftrace_op(op, ftrace_ops_list) {
5214 if (ftrace_ops_test(op, ip, regs)) {
5215 if (FTRACE_WARN_ON(!op->func)) {
5216 pr_warn("op=%p %pS\n", op, op);
5219 op->func(ip, parent_ip, op, regs);
5221 } while_for_each_ftrace_op(op);
5223 preempt_enable_notrace();
5224 trace_clear_recursion(bit);
5228 * Some archs only support passing ip and parent_ip. Even though
5229 * the list function ignores the op parameter, we do not want any
5230 * C side effects, where a function is called without the caller
5231 * sending a third parameter.
5232 * Archs are to support both the regs and ftrace_ops at the same time.
5233 * If they support ftrace_ops, it is assumed they support regs.
5234 * If call backs want to use regs, they must either check for regs
5235 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
5236 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
5237 * An architecture can pass partial regs with ftrace_ops and still
5238 * set the ARCH_SUPPORT_FTARCE_OPS.
5240 #if ARCH_SUPPORTS_FTRACE_OPS
5241 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
5242 struct ftrace_ops *op, struct pt_regs *regs)
5244 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
5247 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
5249 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
5254 * If there's only one function registered but it does not support
5255 * recursion, this function will be called by the mcount trampoline.
5256 * This function will handle recursion protection.
5258 static void ftrace_ops_recurs_func(unsigned long ip, unsigned long parent_ip,
5259 struct ftrace_ops *op, struct pt_regs *regs)
5263 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
5267 op->func(ip, parent_ip, op, regs);
5269 trace_clear_recursion(bit);
5273 * ftrace_ops_get_func - get the function a trampoline should call
5274 * @ops: the ops to get the function for
5276 * Normally the mcount trampoline will call the ops->func, but there
5277 * are times that it should not. For example, if the ops does not
5278 * have its own recursion protection, then it should call the
5279 * ftrace_ops_recurs_func() instead.
5281 * Returns the function that the trampoline should call for @ops.
5283 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
5286 * If the func handles its own recursion, call it directly.
5287 * Otherwise call the recursion protected function that
5288 * will call the ftrace ops function.
5290 if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE))
5291 return ftrace_ops_recurs_func;
5296 static void clear_ftrace_swapper(void)
5298 struct task_struct *p;
5302 for_each_online_cpu(cpu) {
5304 clear_tsk_trace_trace(p);
5309 static void set_ftrace_swapper(void)
5311 struct task_struct *p;
5315 for_each_online_cpu(cpu) {
5317 set_tsk_trace_trace(p);
5322 static void clear_ftrace_pid(struct pid *pid)
5324 struct task_struct *p;
5327 do_each_pid_task(pid, PIDTYPE_PID, p) {
5328 clear_tsk_trace_trace(p);
5329 } while_each_pid_task(pid, PIDTYPE_PID, p);
5335 static void set_ftrace_pid(struct pid *pid)
5337 struct task_struct *p;
5340 do_each_pid_task(pid, PIDTYPE_PID, p) {
5341 set_tsk_trace_trace(p);
5342 } while_each_pid_task(pid, PIDTYPE_PID, p);
5346 static void clear_ftrace_pid_task(struct pid *pid)
5348 if (pid == ftrace_swapper_pid)
5349 clear_ftrace_swapper();
5351 clear_ftrace_pid(pid);
5354 static void set_ftrace_pid_task(struct pid *pid)
5356 if (pid == ftrace_swapper_pid)
5357 set_ftrace_swapper();
5359 set_ftrace_pid(pid);
5362 static int ftrace_pid_add(int p)
5365 struct ftrace_pid *fpid;
5368 mutex_lock(&ftrace_lock);
5371 pid = ftrace_swapper_pid;
5373 pid = find_get_pid(p);
5380 list_for_each_entry(fpid, &ftrace_pids, list)
5381 if (fpid->pid == pid)
5386 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
5390 list_add(&fpid->list, &ftrace_pids);
5393 set_ftrace_pid_task(pid);
5395 ftrace_update_pid_func();
5397 ftrace_startup_all(0);
5399 mutex_unlock(&ftrace_lock);
5403 if (pid != ftrace_swapper_pid)
5407 mutex_unlock(&ftrace_lock);
5411 static void ftrace_pid_reset(void)
5413 struct ftrace_pid *fpid, *safe;
5415 mutex_lock(&ftrace_lock);
5416 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
5417 struct pid *pid = fpid->pid;
5419 clear_ftrace_pid_task(pid);
5421 list_del(&fpid->list);
5425 ftrace_update_pid_func();
5426 ftrace_startup_all(0);
5428 mutex_unlock(&ftrace_lock);
5431 static void *fpid_start(struct seq_file *m, loff_t *pos)
5433 mutex_lock(&ftrace_lock);
5435 if (!ftrace_pids_enabled() && (!*pos))
5438 return seq_list_start(&ftrace_pids, *pos);
5441 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
5446 return seq_list_next(v, &ftrace_pids, pos);
5449 static void fpid_stop(struct seq_file *m, void *p)
5451 mutex_unlock(&ftrace_lock);
5454 static int fpid_show(struct seq_file *m, void *v)
5456 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
5458 if (v == (void *)1) {
5459 seq_puts(m, "no pid\n");
5463 if (fpid->pid == ftrace_swapper_pid)
5464 seq_puts(m, "swapper tasks\n");
5466 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
5471 static const struct seq_operations ftrace_pid_sops = {
5472 .start = fpid_start,
5479 ftrace_pid_open(struct inode *inode, struct file *file)
5483 if ((file->f_mode & FMODE_WRITE) &&
5484 (file->f_flags & O_TRUNC))
5487 if (file->f_mode & FMODE_READ)
5488 ret = seq_open(file, &ftrace_pid_sops);
5494 ftrace_pid_write(struct file *filp, const char __user *ubuf,
5495 size_t cnt, loff_t *ppos)
5501 if (cnt >= sizeof(buf))
5504 if (copy_from_user(&buf, ubuf, cnt))
5510 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
5511 * to clean the filter quietly.
5513 tmp = strstrip(buf);
5514 if (strlen(tmp) == 0)
5517 ret = kstrtol(tmp, 10, &val);
5521 ret = ftrace_pid_add(val);
5523 return ret ? ret : cnt;
5527 ftrace_pid_release(struct inode *inode, struct file *file)
5529 if (file->f_mode & FMODE_READ)
5530 seq_release(inode, file);
5535 static const struct file_operations ftrace_pid_fops = {
5536 .open = ftrace_pid_open,
5537 .write = ftrace_pid_write,
5539 .llseek = tracing_lseek,
5540 .release = ftrace_pid_release,
5543 static __init int ftrace_init_tracefs(void)
5545 struct dentry *d_tracer;
5547 d_tracer = tracing_init_dentry();
5548 if (IS_ERR(d_tracer))
5551 ftrace_init_dyn_tracefs(d_tracer);
5553 trace_create_file("set_ftrace_pid", 0644, d_tracer,
5554 NULL, &ftrace_pid_fops);
5556 ftrace_profile_tracefs(d_tracer);
5560 fs_initcall(ftrace_init_tracefs);
5563 * ftrace_kill - kill ftrace
5565 * This function should be used by panic code. It stops ftrace
5566 * but in a not so nice way. If you need to simply kill ftrace
5567 * from a non-atomic section, use ftrace_kill.
5569 void ftrace_kill(void)
5571 ftrace_disabled = 1;
5573 clear_ftrace_function();
5577 * Test if ftrace is dead or not.
5579 int ftrace_is_dead(void)
5581 return ftrace_disabled;
5585 * register_ftrace_function - register a function for profiling
5586 * @ops - ops structure that holds the function for profiling.
5588 * Register a function to be called by all functions in the
5591 * Note: @ops->func and all the functions it calls must be labeled
5592 * with "notrace", otherwise it will go into a
5595 int register_ftrace_function(struct ftrace_ops *ops)
5599 ftrace_ops_init(ops);
5601 mutex_lock(&ftrace_lock);
5603 ret = ftrace_startup(ops, 0);
5605 mutex_unlock(&ftrace_lock);
5609 EXPORT_SYMBOL_GPL(register_ftrace_function);
5612 * unregister_ftrace_function - unregister a function for profiling.
5613 * @ops - ops structure that holds the function to unregister
5615 * Unregister a function that was added to be called by ftrace profiling.
5617 int unregister_ftrace_function(struct ftrace_ops *ops)
5621 mutex_lock(&ftrace_lock);
5622 ret = ftrace_shutdown(ops, 0);
5623 mutex_unlock(&ftrace_lock);
5627 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
5630 ftrace_enable_sysctl(struct ctl_table *table, int write,
5631 void __user *buffer, size_t *lenp,
5636 mutex_lock(&ftrace_lock);
5638 if (unlikely(ftrace_disabled))
5641 ret = proc_dointvec(table, write, buffer, lenp, ppos);
5643 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
5646 last_ftrace_enabled = !!ftrace_enabled;
5648 if (ftrace_enabled) {
5650 /* we are starting ftrace again */
5651 if (ftrace_ops_list != &ftrace_list_end)
5652 update_ftrace_function();
5654 ftrace_startup_sysctl();
5657 /* stopping ftrace calls (just send to ftrace_stub) */
5658 ftrace_trace_function = ftrace_stub;
5660 ftrace_shutdown_sysctl();
5664 mutex_unlock(&ftrace_lock);
5668 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5670 static struct ftrace_ops graph_ops = {
5671 .func = ftrace_stub,
5672 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
5673 FTRACE_OPS_FL_INITIALIZED |
5676 #ifdef FTRACE_GRAPH_TRAMP_ADDR
5677 .trampoline = FTRACE_GRAPH_TRAMP_ADDR,
5678 /* trampoline_size is only needed for dynamically allocated tramps */
5680 ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash)
5683 void ftrace_graph_sleep_time_control(bool enable)
5685 fgraph_sleep_time = enable;
5688 void ftrace_graph_graph_time_control(bool enable)
5690 fgraph_graph_time = enable;
5693 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
5698 /* The callbacks that hook a function */
5699 trace_func_graph_ret_t ftrace_graph_return =
5700 (trace_func_graph_ret_t)ftrace_stub;
5701 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
5702 static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
5704 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
5705 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
5709 unsigned long flags;
5710 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
5711 struct task_struct *g, *t;
5713 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
5714 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
5715 * sizeof(struct ftrace_ret_stack),
5717 if (!ret_stack_list[i]) {
5725 read_lock_irqsave(&tasklist_lock, flags);
5726 do_each_thread(g, t) {
5732 if (t->ret_stack == NULL) {
5733 atomic_set(&t->tracing_graph_pause, 0);
5734 atomic_set(&t->trace_overrun, 0);
5735 t->curr_ret_stack = -1;
5736 /* Make sure the tasks see the -1 first: */
5738 t->ret_stack = ret_stack_list[start++];
5740 } while_each_thread(g, t);
5743 read_unlock_irqrestore(&tasklist_lock, flags);
5745 for (i = start; i < end; i++)
5746 kfree(ret_stack_list[i]);
5751 ftrace_graph_probe_sched_switch(void *ignore, bool preempt,
5752 struct task_struct *prev, struct task_struct *next)
5754 unsigned long long timestamp;
5758 * Does the user want to count the time a function was asleep.
5759 * If so, do not update the time stamps.
5761 if (fgraph_sleep_time)
5764 timestamp = trace_clock_local();
5766 prev->ftrace_timestamp = timestamp;
5768 /* only process tasks that we timestamped */
5769 if (!next->ftrace_timestamp)
5773 * Update all the counters in next to make up for the
5774 * time next was sleeping.
5776 timestamp -= next->ftrace_timestamp;
5778 for (index = next->curr_ret_stack; index >= 0; index--)
5779 next->ret_stack[index].calltime += timestamp;
5782 /* Allocate a return stack for each task */
5783 static int start_graph_tracing(void)
5785 struct ftrace_ret_stack **ret_stack_list;
5788 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
5789 sizeof(struct ftrace_ret_stack *),
5792 if (!ret_stack_list)
5795 /* The cpu_boot init_task->ret_stack will never be freed */
5796 for_each_online_cpu(cpu) {
5797 if (!idle_task(cpu)->ret_stack)
5798 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
5802 ret = alloc_retstack_tasklist(ret_stack_list);
5803 } while (ret == -EAGAIN);
5806 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5808 pr_info("ftrace_graph: Couldn't activate tracepoint"
5809 " probe to kernel_sched_switch\n");
5812 kfree(ret_stack_list);
5817 * Hibernation protection.
5818 * The state of the current task is too much unstable during
5819 * suspend/restore to disk. We want to protect against that.
5822 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
5826 case PM_HIBERNATION_PREPARE:
5827 pause_graph_tracing();
5830 case PM_POST_HIBERNATION:
5831 unpause_graph_tracing();
5837 static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
5839 if (!ftrace_ops_test(&global_ops, trace->func, NULL))
5841 return __ftrace_graph_entry(trace);
5845 * The function graph tracer should only trace the functions defined
5846 * by set_ftrace_filter and set_ftrace_notrace. If another function
5847 * tracer ops is registered, the graph tracer requires testing the
5848 * function against the global ops, and not just trace any function
5849 * that any ftrace_ops registered.
5851 static void update_function_graph_func(void)
5853 struct ftrace_ops *op;
5854 bool do_test = false;
5857 * The graph and global ops share the same set of functions
5858 * to test. If any other ops is on the list, then
5859 * the graph tracing needs to test if its the function
5862 do_for_each_ftrace_op(op, ftrace_ops_list) {
5863 if (op != &global_ops && op != &graph_ops &&
5864 op != &ftrace_list_end) {
5866 /* in double loop, break out with goto */
5869 } while_for_each_ftrace_op(op);
5872 ftrace_graph_entry = ftrace_graph_entry_test;
5874 ftrace_graph_entry = __ftrace_graph_entry;
5877 static struct notifier_block ftrace_suspend_notifier = {
5878 .notifier_call = ftrace_suspend_notifier_call,
5881 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
5882 trace_func_graph_ent_t entryfunc)
5886 mutex_lock(&ftrace_lock);
5888 /* we currently allow only one tracer registered at a time */
5889 if (ftrace_graph_active) {
5894 register_pm_notifier(&ftrace_suspend_notifier);
5896 ftrace_graph_active++;
5897 ret = start_graph_tracing();
5899 ftrace_graph_active--;
5903 ftrace_graph_return = retfunc;
5906 * Update the indirect function to the entryfunc, and the
5907 * function that gets called to the entry_test first. Then
5908 * call the update fgraph entry function to determine if
5909 * the entryfunc should be called directly or not.
5911 __ftrace_graph_entry = entryfunc;
5912 ftrace_graph_entry = ftrace_graph_entry_test;
5913 update_function_graph_func();
5915 ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET);
5917 mutex_unlock(&ftrace_lock);
5921 void unregister_ftrace_graph(void)
5923 mutex_lock(&ftrace_lock);
5925 if (unlikely(!ftrace_graph_active))
5928 ftrace_graph_active--;
5929 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
5930 ftrace_graph_entry = ftrace_graph_entry_stub;
5931 __ftrace_graph_entry = ftrace_graph_entry_stub;
5932 ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET);
5933 unregister_pm_notifier(&ftrace_suspend_notifier);
5934 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5936 #ifdef CONFIG_DYNAMIC_FTRACE
5938 * Function graph does not allocate the trampoline, but
5939 * other global_ops do. We need to reset the ALLOC_TRAMP flag
5942 global_ops.trampoline = save_global_trampoline;
5943 if (save_global_flags & FTRACE_OPS_FL_ALLOC_TRAMP)
5944 global_ops.flags |= FTRACE_OPS_FL_ALLOC_TRAMP;
5948 mutex_unlock(&ftrace_lock);
5951 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
5954 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
5956 atomic_set(&t->tracing_graph_pause, 0);
5957 atomic_set(&t->trace_overrun, 0);
5958 t->ftrace_timestamp = 0;
5959 /* make curr_ret_stack visible before we add the ret_stack */
5961 t->ret_stack = ret_stack;
5965 * Allocate a return stack for the idle task. May be the first
5966 * time through, or it may be done by CPU hotplug online.
5968 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
5970 t->curr_ret_stack = -1;
5972 * The idle task has no parent, it either has its own
5973 * stack or no stack at all.
5976 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
5978 if (ftrace_graph_active) {
5979 struct ftrace_ret_stack *ret_stack;
5981 ret_stack = per_cpu(idle_ret_stack, cpu);
5983 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
5984 * sizeof(struct ftrace_ret_stack),
5988 per_cpu(idle_ret_stack, cpu) = ret_stack;
5990 graph_init_task(t, ret_stack);
5994 /* Allocate a return stack for newly created task */
5995 void ftrace_graph_init_task(struct task_struct *t)
5997 /* Make sure we do not use the parent ret_stack */
5998 t->ret_stack = NULL;
5999 t->curr_ret_stack = -1;
6001 if (ftrace_graph_active) {
6002 struct ftrace_ret_stack *ret_stack;
6004 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
6005 * sizeof(struct ftrace_ret_stack),
6009 graph_init_task(t, ret_stack);
6013 void ftrace_graph_exit_task(struct task_struct *t)
6015 struct ftrace_ret_stack *ret_stack = t->ret_stack;
6017 t->ret_stack = NULL;
6018 /* NULL must become visible to IRQs before we free it: */