1 // SPDX-License-Identifier: GPL-2.0
3 * Infrastructure for profiling code inserted by 'gcc -pg'.
5 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
6 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
8 * Originally ported from the -rt patch by:
9 * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
11 * Based on code in the latency_tracer, that is:
13 * Copyright (C) 2004-2006 Ingo Molnar
14 * Copyright (C) 2004 Nadia Yvette Chambers
17 #include <linux/stop_machine.h>
18 #include <linux/clocksource.h>
19 #include <linux/sched/task.h>
20 #include <linux/kallsyms.h>
21 #include <linux/security.h>
22 #include <linux/seq_file.h>
23 #include <linux/tracefs.h>
24 #include <linux/hardirq.h>
25 #include <linux/kthread.h>
26 #include <linux/uaccess.h>
27 #include <linux/bsearch.h>
28 #include <linux/module.h>
29 #include <linux/ftrace.h>
30 #include <linux/sysctl.h>
31 #include <linux/slab.h>
32 #include <linux/ctype.h>
33 #include <linux/sort.h>
34 #include <linux/list.h>
35 #include <linux/hash.h>
36 #include <linux/rcupdate.h>
37 #include <linux/kprobes.h>
39 #include <trace/events/sched.h>
41 #include <asm/sections.h>
42 #include <asm/setup.h>
44 #include "ftrace_internal.h"
45 #include "trace_output.h"
46 #include "trace_stat.h"
48 #define FTRACE_WARN_ON(cond) \
56 #define FTRACE_WARN_ON_ONCE(cond) \
59 if (WARN_ON_ONCE(___r)) \
64 /* hash bits for specific function selection */
65 #define FTRACE_HASH_DEFAULT_BITS 10
66 #define FTRACE_HASH_MAX_BITS 12
68 #ifdef CONFIG_DYNAMIC_FTRACE
69 #define INIT_OPS_HASH(opsname) \
70 .func_hash = &opsname.local_hash, \
71 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
73 #define INIT_OPS_HASH(opsname)
77 FTRACE_MODIFY_ENABLE_FL = (1 << 0),
78 FTRACE_MODIFY_MAY_SLEEP_FL = (1 << 1),
81 struct ftrace_ops ftrace_list_end __read_mostly = {
83 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
84 INIT_OPS_HASH(ftrace_list_end)
87 /* ftrace_enabled is a method to turn ftrace on or off */
88 int ftrace_enabled __read_mostly;
89 static int last_ftrace_enabled;
91 /* Current function tracing op */
92 struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
93 /* What to set function_trace_op to */
94 static struct ftrace_ops *set_function_trace_op;
96 static bool ftrace_pids_enabled(struct ftrace_ops *ops)
98 struct trace_array *tr;
100 if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
105 return tr->function_pids != NULL || tr->function_no_pids != NULL;
108 static void ftrace_update_trampoline(struct ftrace_ops *ops);
111 * ftrace_disabled is set when an anomaly is discovered.
112 * ftrace_disabled is much stronger than ftrace_enabled.
114 static int ftrace_disabled __read_mostly;
116 DEFINE_MUTEX(ftrace_lock);
118 struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
119 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
120 struct ftrace_ops global_ops;
122 #if ARCH_SUPPORTS_FTRACE_OPS
123 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
124 struct ftrace_ops *op, struct pt_regs *regs);
126 /* See comment below, where ftrace_ops_list_func is defined */
127 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
128 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
131 static inline void ftrace_ops_init(struct ftrace_ops *ops)
133 #ifdef CONFIG_DYNAMIC_FTRACE
134 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
135 mutex_init(&ops->local_hash.regex_lock);
136 ops->func_hash = &ops->local_hash;
137 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
142 #define FTRACE_PID_IGNORE -1
143 #define FTRACE_PID_TRACE -2
145 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
146 struct ftrace_ops *op, struct pt_regs *regs)
148 struct trace_array *tr = op->private;
152 pid = this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid);
153 if (pid == FTRACE_PID_IGNORE)
155 if (pid != FTRACE_PID_TRACE &&
160 op->saved_func(ip, parent_ip, op, regs);
163 static void ftrace_sync_ipi(void *data)
165 /* Probably not needed, but do it anyway */
169 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
172 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
173 * then it needs to call the list anyway.
175 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
176 FTRACE_FORCE_LIST_FUNC)
177 return ftrace_ops_list_func;
179 return ftrace_ops_get_func(ops);
182 static void update_ftrace_function(void)
187 * Prepare the ftrace_ops that the arch callback will use.
188 * If there's only one ftrace_ops registered, the ftrace_ops_list
189 * will point to the ops we want.
191 set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
192 lockdep_is_held(&ftrace_lock));
194 /* If there's no ftrace_ops registered, just call the stub function */
195 if (set_function_trace_op == &ftrace_list_end) {
199 * If we are at the end of the list and this ops is
200 * recursion safe and not dynamic and the arch supports passing ops,
201 * then have the mcount trampoline call the function directly.
203 } else if (rcu_dereference_protected(ftrace_ops_list->next,
204 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
205 func = ftrace_ops_get_list_func(ftrace_ops_list);
208 /* Just use the default ftrace_ops */
209 set_function_trace_op = &ftrace_list_end;
210 func = ftrace_ops_list_func;
213 update_function_graph_func();
215 /* If there's no change, then do nothing more here */
216 if (ftrace_trace_function == func)
220 * If we are using the list function, it doesn't care
221 * about the function_trace_ops.
223 if (func == ftrace_ops_list_func) {
224 ftrace_trace_function = func;
226 * Don't even bother setting function_trace_ops,
227 * it would be racy to do so anyway.
232 #ifndef CONFIG_DYNAMIC_FTRACE
234 * For static tracing, we need to be a bit more careful.
235 * The function change takes affect immediately. Thus,
236 * we need to coorditate the setting of the function_trace_ops
237 * with the setting of the ftrace_trace_function.
239 * Set the function to the list ops, which will call the
240 * function we want, albeit indirectly, but it handles the
241 * ftrace_ops and doesn't depend on function_trace_op.
243 ftrace_trace_function = ftrace_ops_list_func;
245 * Make sure all CPUs see this. Yes this is slow, but static
246 * tracing is slow and nasty to have enabled.
248 synchronize_rcu_tasks_rude();
249 /* Now all cpus are using the list ops. */
250 function_trace_op = set_function_trace_op;
251 /* Make sure the function_trace_op is visible on all CPUs */
253 /* Nasty way to force a rmb on all cpus */
254 smp_call_function(ftrace_sync_ipi, NULL, 1);
255 /* OK, we are all set to update the ftrace_trace_function now! */
256 #endif /* !CONFIG_DYNAMIC_FTRACE */
258 ftrace_trace_function = func;
261 static void add_ftrace_ops(struct ftrace_ops __rcu **list,
262 struct ftrace_ops *ops)
264 rcu_assign_pointer(ops->next, *list);
267 * We are entering ops into the list but another
268 * CPU might be walking that list. We need to make sure
269 * the ops->next pointer is valid before another CPU sees
270 * the ops pointer included into the list.
272 rcu_assign_pointer(*list, ops);
275 static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
276 struct ftrace_ops *ops)
278 struct ftrace_ops **p;
281 * If we are removing the last function, then simply point
282 * to the ftrace_stub.
284 if (rcu_dereference_protected(*list,
285 lockdep_is_held(&ftrace_lock)) == ops &&
286 rcu_dereference_protected(ops->next,
287 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
288 *list = &ftrace_list_end;
292 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
303 static void ftrace_update_trampoline(struct ftrace_ops *ops);
305 int __register_ftrace_function(struct ftrace_ops *ops)
307 if (ops->flags & FTRACE_OPS_FL_DELETED)
310 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
313 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
315 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
316 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
317 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
319 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
320 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
323 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
324 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
326 if (!ftrace_enabled && (ops->flags & FTRACE_OPS_FL_PERMANENT))
329 if (!core_kernel_data((unsigned long)ops))
330 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
332 add_ftrace_ops(&ftrace_ops_list, ops);
334 /* Always save the function, and reset at unregistering */
335 ops->saved_func = ops->func;
337 if (ftrace_pids_enabled(ops))
338 ops->func = ftrace_pid_func;
340 ftrace_update_trampoline(ops);
343 update_ftrace_function();
348 int __unregister_ftrace_function(struct ftrace_ops *ops)
352 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
355 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
361 update_ftrace_function();
363 ops->func = ops->saved_func;
368 static void ftrace_update_pid_func(void)
370 struct ftrace_ops *op;
372 /* Only do something if we are tracing something */
373 if (ftrace_trace_function == ftrace_stub)
376 do_for_each_ftrace_op(op, ftrace_ops_list) {
377 if (op->flags & FTRACE_OPS_FL_PID) {
378 op->func = ftrace_pids_enabled(op) ?
379 ftrace_pid_func : op->saved_func;
380 ftrace_update_trampoline(op);
382 } while_for_each_ftrace_op(op);
384 update_ftrace_function();
387 #ifdef CONFIG_FUNCTION_PROFILER
388 struct ftrace_profile {
389 struct hlist_node node;
391 unsigned long counter;
392 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
393 unsigned long long time;
394 unsigned long long time_squared;
398 struct ftrace_profile_page {
399 struct ftrace_profile_page *next;
401 struct ftrace_profile records[];
404 struct ftrace_profile_stat {
406 struct hlist_head *hash;
407 struct ftrace_profile_page *pages;
408 struct ftrace_profile_page *start;
409 struct tracer_stat stat;
412 #define PROFILE_RECORDS_SIZE \
413 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
415 #define PROFILES_PER_PAGE \
416 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
418 static int ftrace_profile_enabled __read_mostly;
420 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
421 static DEFINE_MUTEX(ftrace_profile_lock);
423 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
425 #define FTRACE_PROFILE_HASH_BITS 10
426 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
429 function_stat_next(void *v, int idx)
431 struct ftrace_profile *rec = v;
432 struct ftrace_profile_page *pg;
434 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
440 if ((void *)rec >= (void *)&pg->records[pg->index]) {
444 rec = &pg->records[0];
452 static void *function_stat_start(struct tracer_stat *trace)
454 struct ftrace_profile_stat *stat =
455 container_of(trace, struct ftrace_profile_stat, stat);
457 if (!stat || !stat->start)
460 return function_stat_next(&stat->start->records[0], 0);
463 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
464 /* function graph compares on total time */
465 static int function_stat_cmp(const void *p1, const void *p2)
467 const struct ftrace_profile *a = p1;
468 const struct ftrace_profile *b = p2;
470 if (a->time < b->time)
472 if (a->time > b->time)
478 /* not function graph compares against hits */
479 static int function_stat_cmp(const void *p1, const void *p2)
481 const struct ftrace_profile *a = p1;
482 const struct ftrace_profile *b = p2;
484 if (a->counter < b->counter)
486 if (a->counter > b->counter)
493 static int function_stat_headers(struct seq_file *m)
495 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
496 seq_puts(m, " Function "
499 "--- ---- --- ---\n");
501 seq_puts(m, " Function Hit\n"
507 static int function_stat_show(struct seq_file *m, void *v)
509 struct ftrace_profile *rec = v;
510 char str[KSYM_SYMBOL_LEN];
512 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
513 static struct trace_seq s;
514 unsigned long long avg;
515 unsigned long long stddev;
517 mutex_lock(&ftrace_profile_lock);
519 /* we raced with function_profile_reset() */
520 if (unlikely(rec->counter == 0)) {
525 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
526 avg = div64_ul(rec->time, rec->counter);
527 if (tracing_thresh && (avg < tracing_thresh))
531 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
532 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
534 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
537 /* Sample standard deviation (s^2) */
538 if (rec->counter <= 1)
542 * Apply Welford's method:
543 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
545 stddev = rec->counter * rec->time_squared -
546 rec->time * rec->time;
549 * Divide only 1000 for ns^2 -> us^2 conversion.
550 * trace_print_graph_duration will divide 1000 again.
552 stddev = div64_ul(stddev,
553 rec->counter * (rec->counter - 1) * 1000);
557 trace_print_graph_duration(rec->time, &s);
558 trace_seq_puts(&s, " ");
559 trace_print_graph_duration(avg, &s);
560 trace_seq_puts(&s, " ");
561 trace_print_graph_duration(stddev, &s);
562 trace_print_seq(m, &s);
566 mutex_unlock(&ftrace_profile_lock);
571 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
573 struct ftrace_profile_page *pg;
575 pg = stat->pages = stat->start;
578 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
583 memset(stat->hash, 0,
584 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
587 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
589 struct ftrace_profile_page *pg;
594 /* If we already allocated, do nothing */
598 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
602 #ifdef CONFIG_DYNAMIC_FTRACE
603 functions = ftrace_update_tot_cnt;
606 * We do not know the number of functions that exist because
607 * dynamic tracing is what counts them. With past experience
608 * we have around 20K functions. That should be more than enough.
609 * It is highly unlikely we will execute every function in
615 pg = stat->start = stat->pages;
617 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
619 for (i = 1; i < pages; i++) {
620 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
631 unsigned long tmp = (unsigned long)pg;
643 static int ftrace_profile_init_cpu(int cpu)
645 struct ftrace_profile_stat *stat;
648 stat = &per_cpu(ftrace_profile_stats, cpu);
651 /* If the profile is already created, simply reset it */
652 ftrace_profile_reset(stat);
657 * We are profiling all functions, but usually only a few thousand
658 * functions are hit. We'll make a hash of 1024 items.
660 size = FTRACE_PROFILE_HASH_SIZE;
662 stat->hash = kcalloc(size, sizeof(struct hlist_head), GFP_KERNEL);
667 /* Preallocate the function profiling pages */
668 if (ftrace_profile_pages_init(stat) < 0) {
677 static int ftrace_profile_init(void)
682 for_each_possible_cpu(cpu) {
683 ret = ftrace_profile_init_cpu(cpu);
691 /* interrupts must be disabled */
692 static struct ftrace_profile *
693 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
695 struct ftrace_profile *rec;
696 struct hlist_head *hhd;
699 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
700 hhd = &stat->hash[key];
702 if (hlist_empty(hhd))
705 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
713 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
714 struct ftrace_profile *rec)
718 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
719 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
723 * The memory is already allocated, this simply finds a new record to use.
725 static struct ftrace_profile *
726 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
728 struct ftrace_profile *rec = NULL;
730 /* prevent recursion (from NMIs) */
731 if (atomic_inc_return(&stat->disabled) != 1)
735 * Try to find the function again since an NMI
736 * could have added it
738 rec = ftrace_find_profiled_func(stat, ip);
742 if (stat->pages->index == PROFILES_PER_PAGE) {
743 if (!stat->pages->next)
745 stat->pages = stat->pages->next;
748 rec = &stat->pages->records[stat->pages->index++];
750 ftrace_add_profile(stat, rec);
753 atomic_dec(&stat->disabled);
759 function_profile_call(unsigned long ip, unsigned long parent_ip,
760 struct ftrace_ops *ops, struct pt_regs *regs)
762 struct ftrace_profile_stat *stat;
763 struct ftrace_profile *rec;
766 if (!ftrace_profile_enabled)
769 local_irq_save(flags);
771 stat = this_cpu_ptr(&ftrace_profile_stats);
772 if (!stat->hash || !ftrace_profile_enabled)
775 rec = ftrace_find_profiled_func(stat, ip);
777 rec = ftrace_profile_alloc(stat, ip);
784 local_irq_restore(flags);
787 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
788 static bool fgraph_graph_time = true;
790 void ftrace_graph_graph_time_control(bool enable)
792 fgraph_graph_time = enable;
795 static int profile_graph_entry(struct ftrace_graph_ent *trace)
797 struct ftrace_ret_stack *ret_stack;
799 function_profile_call(trace->func, 0, NULL, NULL);
801 /* If function graph is shutting down, ret_stack can be NULL */
802 if (!current->ret_stack)
805 ret_stack = ftrace_graph_get_ret_stack(current, 0);
807 ret_stack->subtime = 0;
812 static void profile_graph_return(struct ftrace_graph_ret *trace)
814 struct ftrace_ret_stack *ret_stack;
815 struct ftrace_profile_stat *stat;
816 unsigned long long calltime;
817 struct ftrace_profile *rec;
820 local_irq_save(flags);
821 stat = this_cpu_ptr(&ftrace_profile_stats);
822 if (!stat->hash || !ftrace_profile_enabled)
825 /* If the calltime was zero'd ignore it */
826 if (!trace->calltime)
829 calltime = trace->rettime - trace->calltime;
831 if (!fgraph_graph_time) {
833 /* Append this call time to the parent time to subtract */
834 ret_stack = ftrace_graph_get_ret_stack(current, 1);
836 ret_stack->subtime += calltime;
838 ret_stack = ftrace_graph_get_ret_stack(current, 0);
839 if (ret_stack && ret_stack->subtime < calltime)
840 calltime -= ret_stack->subtime;
845 rec = ftrace_find_profiled_func(stat, trace->func);
847 rec->time += calltime;
848 rec->time_squared += calltime * calltime;
852 local_irq_restore(flags);
855 static struct fgraph_ops fprofiler_ops = {
856 .entryfunc = &profile_graph_entry,
857 .retfunc = &profile_graph_return,
860 static int register_ftrace_profiler(void)
862 return register_ftrace_graph(&fprofiler_ops);
865 static void unregister_ftrace_profiler(void)
867 unregister_ftrace_graph(&fprofiler_ops);
870 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
871 .func = function_profile_call,
872 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
873 INIT_OPS_HASH(ftrace_profile_ops)
876 static int register_ftrace_profiler(void)
878 return register_ftrace_function(&ftrace_profile_ops);
881 static void unregister_ftrace_profiler(void)
883 unregister_ftrace_function(&ftrace_profile_ops);
885 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
888 ftrace_profile_write(struct file *filp, const char __user *ubuf,
889 size_t cnt, loff_t *ppos)
894 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
900 mutex_lock(&ftrace_profile_lock);
901 if (ftrace_profile_enabled ^ val) {
903 ret = ftrace_profile_init();
909 ret = register_ftrace_profiler();
914 ftrace_profile_enabled = 1;
916 ftrace_profile_enabled = 0;
918 * unregister_ftrace_profiler calls stop_machine
919 * so this acts like an synchronize_rcu.
921 unregister_ftrace_profiler();
925 mutex_unlock(&ftrace_profile_lock);
933 ftrace_profile_read(struct file *filp, char __user *ubuf,
934 size_t cnt, loff_t *ppos)
936 char buf[64]; /* big enough to hold a number */
939 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
940 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
943 static const struct file_operations ftrace_profile_fops = {
944 .open = tracing_open_generic,
945 .read = ftrace_profile_read,
946 .write = ftrace_profile_write,
947 .llseek = default_llseek,
950 /* used to initialize the real stat files */
951 static struct tracer_stat function_stats __initdata = {
953 .stat_start = function_stat_start,
954 .stat_next = function_stat_next,
955 .stat_cmp = function_stat_cmp,
956 .stat_headers = function_stat_headers,
957 .stat_show = function_stat_show
960 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
962 struct ftrace_profile_stat *stat;
963 struct dentry *entry;
968 for_each_possible_cpu(cpu) {
969 stat = &per_cpu(ftrace_profile_stats, cpu);
971 name = kasprintf(GFP_KERNEL, "function%d", cpu);
974 * The files created are permanent, if something happens
975 * we still do not free memory.
978 "Could not allocate stat file for cpu %d\n",
982 stat->stat = function_stats;
983 stat->stat.name = name;
984 ret = register_stat_tracer(&stat->stat);
987 "Could not register function stat for cpu %d\n",
994 entry = tracefs_create_file("function_profile_enabled", 0644,
995 d_tracer, NULL, &ftrace_profile_fops);
997 pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
1000 #else /* CONFIG_FUNCTION_PROFILER */
1001 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1004 #endif /* CONFIG_FUNCTION_PROFILER */
1006 #ifdef CONFIG_DYNAMIC_FTRACE
1008 static struct ftrace_ops *removed_ops;
1011 * Set when doing a global update, like enabling all recs or disabling them.
1012 * It is not set when just updating a single ftrace_ops.
1014 static bool update_all_ops;
1016 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1017 # error Dynamic ftrace depends on MCOUNT_RECORD
1020 struct ftrace_func_probe {
1021 struct ftrace_probe_ops *probe_ops;
1022 struct ftrace_ops ops;
1023 struct trace_array *tr;
1024 struct list_head list;
1030 * We make these constant because no one should touch them,
1031 * but they are used as the default "empty hash", to avoid allocating
1032 * it all the time. These are in a read only section such that if
1033 * anyone does try to modify it, it will cause an exception.
1035 static const struct hlist_head empty_buckets[1];
1036 static const struct ftrace_hash empty_hash = {
1037 .buckets = (struct hlist_head *)empty_buckets,
1039 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1041 struct ftrace_ops global_ops = {
1042 .func = ftrace_stub,
1043 .local_hash.notrace_hash = EMPTY_HASH,
1044 .local_hash.filter_hash = EMPTY_HASH,
1045 INIT_OPS_HASH(global_ops)
1046 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
1047 FTRACE_OPS_FL_INITIALIZED |
1052 * Used by the stack undwinder to know about dynamic ftrace trampolines.
1054 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
1056 struct ftrace_ops *op = NULL;
1059 * Some of the ops may be dynamically allocated,
1060 * they are freed after a synchronize_rcu().
1062 preempt_disable_notrace();
1064 do_for_each_ftrace_op(op, ftrace_ops_list) {
1066 * This is to check for dynamically allocated trampolines.
1067 * Trampolines that are in kernel text will have
1068 * core_kernel_text() return true.
1070 if (op->trampoline && op->trampoline_size)
1071 if (addr >= op->trampoline &&
1072 addr < op->trampoline + op->trampoline_size) {
1073 preempt_enable_notrace();
1076 } while_for_each_ftrace_op(op);
1077 preempt_enable_notrace();
1083 * This is used by __kernel_text_address() to return true if the
1084 * address is on a dynamically allocated trampoline that would
1085 * not return true for either core_kernel_text() or
1086 * is_module_text_address().
1088 bool is_ftrace_trampoline(unsigned long addr)
1090 return ftrace_ops_trampoline(addr) != NULL;
1093 struct ftrace_page {
1094 struct ftrace_page *next;
1095 struct dyn_ftrace *records;
1100 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1101 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1103 static struct ftrace_page *ftrace_pages_start;
1104 static struct ftrace_page *ftrace_pages;
1106 static __always_inline unsigned long
1107 ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1109 if (hash->size_bits > 0)
1110 return hash_long(ip, hash->size_bits);
1115 /* Only use this function if ftrace_hash_empty() has already been tested */
1116 static __always_inline struct ftrace_func_entry *
1117 __ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1120 struct ftrace_func_entry *entry;
1121 struct hlist_head *hhd;
1123 key = ftrace_hash_key(hash, ip);
1124 hhd = &hash->buckets[key];
1126 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1127 if (entry->ip == ip)
1134 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1135 * @hash: The hash to look at
1136 * @ip: The instruction pointer to test
1138 * Search a given @hash to see if a given instruction pointer (@ip)
1141 * Returns the entry that holds the @ip if found. NULL otherwise.
1143 struct ftrace_func_entry *
1144 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1146 if (ftrace_hash_empty(hash))
1149 return __ftrace_lookup_ip(hash, ip);
1152 static void __add_hash_entry(struct ftrace_hash *hash,
1153 struct ftrace_func_entry *entry)
1155 struct hlist_head *hhd;
1158 key = ftrace_hash_key(hash, entry->ip);
1159 hhd = &hash->buckets[key];
1160 hlist_add_head(&entry->hlist, hhd);
1164 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1166 struct ftrace_func_entry *entry;
1168 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1173 __add_hash_entry(hash, entry);
1179 free_hash_entry(struct ftrace_hash *hash,
1180 struct ftrace_func_entry *entry)
1182 hlist_del(&entry->hlist);
1188 remove_hash_entry(struct ftrace_hash *hash,
1189 struct ftrace_func_entry *entry)
1191 hlist_del_rcu(&entry->hlist);
1195 static void ftrace_hash_clear(struct ftrace_hash *hash)
1197 struct hlist_head *hhd;
1198 struct hlist_node *tn;
1199 struct ftrace_func_entry *entry;
1200 int size = 1 << hash->size_bits;
1206 for (i = 0; i < size; i++) {
1207 hhd = &hash->buckets[i];
1208 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1209 free_hash_entry(hash, entry);
1211 FTRACE_WARN_ON(hash->count);
1214 static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1216 list_del(&ftrace_mod->list);
1217 kfree(ftrace_mod->module);
1218 kfree(ftrace_mod->func);
1222 static void clear_ftrace_mod_list(struct list_head *head)
1224 struct ftrace_mod_load *p, *n;
1226 /* stack tracer isn't supported yet */
1230 mutex_lock(&ftrace_lock);
1231 list_for_each_entry_safe(p, n, head, list)
1233 mutex_unlock(&ftrace_lock);
1236 static void free_ftrace_hash(struct ftrace_hash *hash)
1238 if (!hash || hash == EMPTY_HASH)
1240 ftrace_hash_clear(hash);
1241 kfree(hash->buckets);
1245 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1247 struct ftrace_hash *hash;
1249 hash = container_of(rcu, struct ftrace_hash, rcu);
1250 free_ftrace_hash(hash);
1253 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1255 if (!hash || hash == EMPTY_HASH)
1257 call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
1260 void ftrace_free_filter(struct ftrace_ops *ops)
1262 ftrace_ops_init(ops);
1263 free_ftrace_hash(ops->func_hash->filter_hash);
1264 free_ftrace_hash(ops->func_hash->notrace_hash);
1267 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1269 struct ftrace_hash *hash;
1272 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1276 size = 1 << size_bits;
1277 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1279 if (!hash->buckets) {
1284 hash->size_bits = size_bits;
1290 static int ftrace_add_mod(struct trace_array *tr,
1291 const char *func, const char *module,
1294 struct ftrace_mod_load *ftrace_mod;
1295 struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1297 ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1301 ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1302 ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1303 ftrace_mod->enable = enable;
1305 if (!ftrace_mod->func || !ftrace_mod->module)
1308 list_add(&ftrace_mod->list, mod_head);
1313 free_ftrace_mod(ftrace_mod);
1318 static struct ftrace_hash *
1319 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1321 struct ftrace_func_entry *entry;
1322 struct ftrace_hash *new_hash;
1327 new_hash = alloc_ftrace_hash(size_bits);
1332 new_hash->flags = hash->flags;
1335 if (ftrace_hash_empty(hash))
1338 size = 1 << hash->size_bits;
1339 for (i = 0; i < size; i++) {
1340 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1341 ret = add_hash_entry(new_hash, entry->ip);
1347 FTRACE_WARN_ON(new_hash->count != hash->count);
1352 free_ftrace_hash(new_hash);
1357 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1359 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1361 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1362 struct ftrace_hash *new_hash);
1364 static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size)
1366 struct ftrace_func_entry *entry;
1367 struct ftrace_hash *new_hash;
1368 struct hlist_head *hhd;
1369 struct hlist_node *tn;
1374 * Make the hash size about 1/2 the # found
1376 for (size /= 2; size; size >>= 1)
1379 /* Don't allocate too much */
1380 if (bits > FTRACE_HASH_MAX_BITS)
1381 bits = FTRACE_HASH_MAX_BITS;
1383 new_hash = alloc_ftrace_hash(bits);
1387 new_hash->flags = src->flags;
1389 size = 1 << src->size_bits;
1390 for (i = 0; i < size; i++) {
1391 hhd = &src->buckets[i];
1392 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1393 remove_hash_entry(src, entry);
1394 __add_hash_entry(new_hash, entry);
1400 static struct ftrace_hash *
1401 __ftrace_hash_move(struct ftrace_hash *src)
1403 int size = src->count;
1406 * If the new source is empty, just return the empty_hash.
1408 if (ftrace_hash_empty(src))
1411 return dup_hash(src, size);
1415 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1416 struct ftrace_hash **dst, struct ftrace_hash *src)
1418 struct ftrace_hash *new_hash;
1421 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1422 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1425 new_hash = __ftrace_hash_move(src);
1429 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1431 /* IPMODIFY should be updated only when filter_hash updating */
1432 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1434 free_ftrace_hash(new_hash);
1440 * Remove the current set, update the hash and add
1443 ftrace_hash_rec_disable_modify(ops, enable);
1445 rcu_assign_pointer(*dst, new_hash);
1447 ftrace_hash_rec_enable_modify(ops, enable);
1452 static bool hash_contains_ip(unsigned long ip,
1453 struct ftrace_ops_hash *hash)
1456 * The function record is a match if it exists in the filter
1457 * hash and not in the notrace hash. Note, an emty hash is
1458 * considered a match for the filter hash, but an empty
1459 * notrace hash is considered not in the notrace hash.
1461 return (ftrace_hash_empty(hash->filter_hash) ||
1462 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1463 (ftrace_hash_empty(hash->notrace_hash) ||
1464 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1468 * Test the hashes for this ops to see if we want to call
1469 * the ops->func or not.
1471 * It's a match if the ip is in the ops->filter_hash or
1472 * the filter_hash does not exist or is empty,
1474 * the ip is not in the ops->notrace_hash.
1476 * This needs to be called with preemption disabled as
1477 * the hashes are freed with call_rcu().
1480 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1482 struct ftrace_ops_hash hash;
1485 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1487 * There's a small race when adding ops that the ftrace handler
1488 * that wants regs, may be called without them. We can not
1489 * allow that handler to be called if regs is NULL.
1491 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1495 rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1496 rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1498 if (hash_contains_ip(ip, &hash))
1507 * This is a double for. Do not use 'break' to break out of the loop,
1508 * you must use a goto.
1510 #define do_for_each_ftrace_rec(pg, rec) \
1511 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1513 for (_____i = 0; _____i < pg->index; _____i++) { \
1514 rec = &pg->records[_____i];
1516 #define while_for_each_ftrace_rec() \
1521 static int ftrace_cmp_recs(const void *a, const void *b)
1523 const struct dyn_ftrace *key = a;
1524 const struct dyn_ftrace *rec = b;
1526 if (key->flags < rec->ip)
1528 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1533 static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
1535 struct ftrace_page *pg;
1536 struct dyn_ftrace *rec = NULL;
1537 struct dyn_ftrace key;
1540 key.flags = end; /* overload flags, as it is unsigned long */
1542 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1543 if (end < pg->records[0].ip ||
1544 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1546 rec = bsearch(&key, pg->records, pg->index,
1547 sizeof(struct dyn_ftrace),
1556 * ftrace_location_range - return the first address of a traced location
1557 * if it touches the given ip range
1558 * @start: start of range to search.
1559 * @end: end of range to search (inclusive). @end points to the last byte
1562 * Returns rec->ip if the related ftrace location is a least partly within
1563 * the given address range. That is, the first address of the instruction
1564 * that is either a NOP or call to the function tracer. It checks the ftrace
1565 * internal tables to determine if the address belongs or not.
1567 unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1569 struct dyn_ftrace *rec;
1571 rec = lookup_rec(start, end);
1579 * ftrace_location - return true if the ip giving is a traced location
1580 * @ip: the instruction pointer to check
1582 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1583 * That is, the instruction that is either a NOP or call to
1584 * the function tracer. It checks the ftrace internal tables to
1585 * determine if the address belongs or not.
1587 unsigned long ftrace_location(unsigned long ip)
1589 return ftrace_location_range(ip, ip);
1593 * ftrace_text_reserved - return true if range contains an ftrace location
1594 * @start: start of range to search
1595 * @end: end of range to search (inclusive). @end points to the last byte to check.
1597 * Returns 1 if @start and @end contains a ftrace location.
1598 * That is, the instruction that is either a NOP or call to
1599 * the function tracer. It checks the ftrace internal tables to
1600 * determine if the address belongs or not.
1602 int ftrace_text_reserved(const void *start, const void *end)
1606 ret = ftrace_location_range((unsigned long)start,
1607 (unsigned long)end);
1612 /* Test if ops registered to this rec needs regs */
1613 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1615 struct ftrace_ops *ops;
1616 bool keep_regs = false;
1618 for (ops = ftrace_ops_list;
1619 ops != &ftrace_list_end; ops = ops->next) {
1620 /* pass rec in as regs to have non-NULL val */
1621 if (ftrace_ops_test(ops, rec->ip, rec)) {
1622 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1632 static struct ftrace_ops *
1633 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1634 static struct ftrace_ops *
1635 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1637 static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1641 struct ftrace_hash *hash;
1642 struct ftrace_hash *other_hash;
1643 struct ftrace_page *pg;
1644 struct dyn_ftrace *rec;
1645 bool update = false;
1649 /* Only update if the ops has been registered */
1650 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1654 * In the filter_hash case:
1655 * If the count is zero, we update all records.
1656 * Otherwise we just update the items in the hash.
1658 * In the notrace_hash case:
1659 * We enable the update in the hash.
1660 * As disabling notrace means enabling the tracing,
1661 * and enabling notrace means disabling, the inc variable
1665 hash = ops->func_hash->filter_hash;
1666 other_hash = ops->func_hash->notrace_hash;
1667 if (ftrace_hash_empty(hash))
1671 hash = ops->func_hash->notrace_hash;
1672 other_hash = ops->func_hash->filter_hash;
1674 * If the notrace hash has no items,
1675 * then there's nothing to do.
1677 if (ftrace_hash_empty(hash))
1681 do_for_each_ftrace_rec(pg, rec) {
1682 int in_other_hash = 0;
1686 if (rec->flags & FTRACE_FL_DISABLED)
1691 * Only the filter_hash affects all records.
1692 * Update if the record is not in the notrace hash.
1694 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1697 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1698 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1701 * If filter_hash is set, we want to match all functions
1702 * that are in the hash but not in the other hash.
1704 * If filter_hash is not set, then we are decrementing.
1705 * That means we match anything that is in the hash
1706 * and also in the other_hash. That is, we need to turn
1707 * off functions in the other hash because they are disabled
1710 if (filter_hash && in_hash && !in_other_hash)
1712 else if (!filter_hash && in_hash &&
1713 (in_other_hash || ftrace_hash_empty(other_hash)))
1721 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1724 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1725 rec->flags |= FTRACE_FL_DIRECT;
1728 * If there's only a single callback registered to a
1729 * function, and the ops has a trampoline registered
1730 * for it, then we can call it directly.
1732 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1733 rec->flags |= FTRACE_FL_TRAMP;
1736 * If we are adding another function callback
1737 * to this function, and the previous had a
1738 * custom trampoline in use, then we need to go
1739 * back to the default trampoline.
1741 rec->flags &= ~FTRACE_FL_TRAMP;
1744 * If any ops wants regs saved for this function
1745 * then all ops will get saved regs.
1747 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1748 rec->flags |= FTRACE_FL_REGS;
1750 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1755 * Only the internal direct_ops should have the
1756 * DIRECT flag set. Thus, if it is removing a
1757 * function, then that function should no longer
1760 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1761 rec->flags &= ~FTRACE_FL_DIRECT;
1764 * If the rec had REGS enabled and the ops that is
1765 * being removed had REGS set, then see if there is
1766 * still any ops for this record that wants regs.
1767 * If not, we can stop recording them.
1769 if (ftrace_rec_count(rec) > 0 &&
1770 rec->flags & FTRACE_FL_REGS &&
1771 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1772 if (!test_rec_ops_needs_regs(rec))
1773 rec->flags &= ~FTRACE_FL_REGS;
1777 * The TRAMP needs to be set only if rec count
1778 * is decremented to one, and the ops that is
1779 * left has a trampoline. As TRAMP can only be
1780 * enabled if there is only a single ops attached
1783 if (ftrace_rec_count(rec) == 1 &&
1784 ftrace_find_tramp_ops_any(rec))
1785 rec->flags |= FTRACE_FL_TRAMP;
1787 rec->flags &= ~FTRACE_FL_TRAMP;
1790 * flags will be cleared in ftrace_check_record()
1791 * if rec count is zero.
1796 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1797 update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1799 /* Shortcut, if we handled all records, we are done. */
1800 if (!all && count == hash->count)
1802 } while_for_each_ftrace_rec();
1807 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1810 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1813 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1816 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1819 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1820 int filter_hash, int inc)
1822 struct ftrace_ops *op;
1824 __ftrace_hash_rec_update(ops, filter_hash, inc);
1826 if (ops->func_hash != &global_ops.local_hash)
1830 * If the ops shares the global_ops hash, then we need to update
1831 * all ops that are enabled and use this hash.
1833 do_for_each_ftrace_op(op, ftrace_ops_list) {
1837 if (op->func_hash == &global_ops.local_hash)
1838 __ftrace_hash_rec_update(op, filter_hash, inc);
1839 } while_for_each_ftrace_op(op);
1842 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1845 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1848 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1851 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1855 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1856 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1857 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1858 * Note that old_hash and new_hash has below meanings
1859 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1860 * - If the hash is EMPTY_HASH, it hits nothing
1861 * - Anything else hits the recs which match the hash entries.
1863 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1864 struct ftrace_hash *old_hash,
1865 struct ftrace_hash *new_hash)
1867 struct ftrace_page *pg;
1868 struct dyn_ftrace *rec, *end = NULL;
1871 /* Only update if the ops has been registered */
1872 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1875 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1879 * Since the IPMODIFY is a very address sensitive action, we do not
1880 * allow ftrace_ops to set all functions to new hash.
1882 if (!new_hash || !old_hash)
1885 /* Update rec->flags */
1886 do_for_each_ftrace_rec(pg, rec) {
1888 if (rec->flags & FTRACE_FL_DISABLED)
1891 /* We need to update only differences of filter_hash */
1892 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1893 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1894 if (in_old == in_new)
1898 /* New entries must ensure no others are using it */
1899 if (rec->flags & FTRACE_FL_IPMODIFY)
1901 rec->flags |= FTRACE_FL_IPMODIFY;
1902 } else /* Removed entry */
1903 rec->flags &= ~FTRACE_FL_IPMODIFY;
1904 } while_for_each_ftrace_rec();
1911 /* Roll back what we did above */
1912 do_for_each_ftrace_rec(pg, rec) {
1914 if (rec->flags & FTRACE_FL_DISABLED)
1920 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1921 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1922 if (in_old == in_new)
1926 rec->flags &= ~FTRACE_FL_IPMODIFY;
1928 rec->flags |= FTRACE_FL_IPMODIFY;
1929 } while_for_each_ftrace_rec();
1935 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1937 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1939 if (ftrace_hash_empty(hash))
1942 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1945 /* Disabling always succeeds */
1946 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1948 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1950 if (ftrace_hash_empty(hash))
1953 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1956 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1957 struct ftrace_hash *new_hash)
1959 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1961 if (ftrace_hash_empty(old_hash))
1964 if (ftrace_hash_empty(new_hash))
1967 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
1970 static void print_ip_ins(const char *fmt, const unsigned char *p)
1974 printk(KERN_CONT "%s", fmt);
1976 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1977 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1980 enum ftrace_bug_type ftrace_bug_type;
1981 const void *ftrace_expected;
1983 static void print_bug_type(void)
1985 switch (ftrace_bug_type) {
1986 case FTRACE_BUG_UNKNOWN:
1988 case FTRACE_BUG_INIT:
1989 pr_info("Initializing ftrace call sites\n");
1991 case FTRACE_BUG_NOP:
1992 pr_info("Setting ftrace call site to NOP\n");
1994 case FTRACE_BUG_CALL:
1995 pr_info("Setting ftrace call site to call ftrace function\n");
1997 case FTRACE_BUG_UPDATE:
1998 pr_info("Updating ftrace call site to call a different ftrace function\n");
2004 * ftrace_bug - report and shutdown function tracer
2005 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2006 * @rec: The record that failed
2008 * The arch code that enables or disables the function tracing
2009 * can call ftrace_bug() when it has detected a problem in
2010 * modifying the code. @failed should be one of either:
2011 * EFAULT - if the problem happens on reading the @ip address
2012 * EINVAL - if what is read at @ip is not what was expected
2013 * EPERM - if the problem happens on writing to the @ip address
2015 void ftrace_bug(int failed, struct dyn_ftrace *rec)
2017 unsigned long ip = rec ? rec->ip : 0;
2021 FTRACE_WARN_ON_ONCE(1);
2022 pr_info("ftrace faulted on modifying ");
2026 FTRACE_WARN_ON_ONCE(1);
2027 pr_info("ftrace failed to modify ");
2029 print_ip_ins(" actual: ", (unsigned char *)ip);
2031 if (ftrace_expected) {
2032 print_ip_ins(" expected: ", ftrace_expected);
2037 FTRACE_WARN_ON_ONCE(1);
2038 pr_info("ftrace faulted on writing ");
2042 FTRACE_WARN_ON_ONCE(1);
2043 pr_info("ftrace faulted on unknown error ");
2048 struct ftrace_ops *ops = NULL;
2050 pr_info("ftrace record flags: %lx\n", rec->flags);
2051 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2052 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2053 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2054 ops = ftrace_find_tramp_ops_any(rec);
2057 pr_cont("\ttramp: %pS (%pS)",
2058 (void *)ops->trampoline,
2060 ops = ftrace_find_tramp_ops_next(rec, ops);
2063 pr_cont("\ttramp: ERROR!");
2066 ip = ftrace_get_addr_curr(rec);
2067 pr_cont("\n expected tramp: %lx\n", ip);
2071 static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2073 unsigned long flag = 0UL;
2075 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2077 if (rec->flags & FTRACE_FL_DISABLED)
2078 return FTRACE_UPDATE_IGNORE;
2081 * If we are updating calls:
2083 * If the record has a ref count, then we need to enable it
2084 * because someone is using it.
2086 * Otherwise we make sure its disabled.
2088 * If we are disabling calls, then disable all records that
2091 if (enable && ftrace_rec_count(rec))
2092 flag = FTRACE_FL_ENABLED;
2095 * If enabling and the REGS flag does not match the REGS_EN, or
2096 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2097 * this record. Set flags to fail the compare against ENABLED.
2098 * Same for direct calls.
2101 if (!(rec->flags & FTRACE_FL_REGS) !=
2102 !(rec->flags & FTRACE_FL_REGS_EN))
2103 flag |= FTRACE_FL_REGS;
2105 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2106 !(rec->flags & FTRACE_FL_TRAMP_EN))
2107 flag |= FTRACE_FL_TRAMP;
2110 * Direct calls are special, as count matters.
2111 * We must test the record for direct, if the
2112 * DIRECT and DIRECT_EN do not match, but only
2113 * if the count is 1. That's because, if the
2114 * count is something other than one, we do not
2115 * want the direct enabled (it will be done via the
2116 * direct helper). But if DIRECT_EN is set, and
2117 * the count is not one, we need to clear it.
2119 if (ftrace_rec_count(rec) == 1) {
2120 if (!(rec->flags & FTRACE_FL_DIRECT) !=
2121 !(rec->flags & FTRACE_FL_DIRECT_EN))
2122 flag |= FTRACE_FL_DIRECT;
2123 } else if (rec->flags & FTRACE_FL_DIRECT_EN) {
2124 flag |= FTRACE_FL_DIRECT;
2128 /* If the state of this record hasn't changed, then do nothing */
2129 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2130 return FTRACE_UPDATE_IGNORE;
2133 /* Save off if rec is being enabled (for return value) */
2134 flag ^= rec->flags & FTRACE_FL_ENABLED;
2137 rec->flags |= FTRACE_FL_ENABLED;
2138 if (flag & FTRACE_FL_REGS) {
2139 if (rec->flags & FTRACE_FL_REGS)
2140 rec->flags |= FTRACE_FL_REGS_EN;
2142 rec->flags &= ~FTRACE_FL_REGS_EN;
2144 if (flag & FTRACE_FL_TRAMP) {
2145 if (rec->flags & FTRACE_FL_TRAMP)
2146 rec->flags |= FTRACE_FL_TRAMP_EN;
2148 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2150 if (flag & FTRACE_FL_DIRECT) {
2152 * If there's only one user (direct_ops helper)
2153 * then we can call the direct function
2154 * directly (no ftrace trampoline).
2156 if (ftrace_rec_count(rec) == 1) {
2157 if (rec->flags & FTRACE_FL_DIRECT)
2158 rec->flags |= FTRACE_FL_DIRECT_EN;
2160 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2163 * Can only call directly if there's
2164 * only one callback to the function.
2166 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2172 * If this record is being updated from a nop, then
2173 * return UPDATE_MAKE_CALL.
2175 * return UPDATE_MODIFY_CALL to tell the caller to convert
2176 * from the save regs, to a non-save regs function or
2177 * vice versa, or from a trampoline call.
2179 if (flag & FTRACE_FL_ENABLED) {
2180 ftrace_bug_type = FTRACE_BUG_CALL;
2181 return FTRACE_UPDATE_MAKE_CALL;
2184 ftrace_bug_type = FTRACE_BUG_UPDATE;
2185 return FTRACE_UPDATE_MODIFY_CALL;
2189 /* If there's no more users, clear all flags */
2190 if (!ftrace_rec_count(rec))
2194 * Just disable the record, but keep the ops TRAMP
2195 * and REGS states. The _EN flags must be disabled though.
2197 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2198 FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN);
2201 ftrace_bug_type = FTRACE_BUG_NOP;
2202 return FTRACE_UPDATE_MAKE_NOP;
2206 * ftrace_update_record, set a record that now is tracing or not
2207 * @rec: the record to update
2208 * @enable: set to true if the record is tracing, false to force disable
2210 * The records that represent all functions that can be traced need
2211 * to be updated when tracing has been enabled.
2213 int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2215 return ftrace_check_record(rec, enable, true);
2219 * ftrace_test_record, check if the record has been enabled or not
2220 * @rec: the record to test
2221 * @enable: set to true to check if enabled, false if it is disabled
2223 * The arch code may need to test if a record is already set to
2224 * tracing to determine how to modify the function code that it
2227 int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2229 return ftrace_check_record(rec, enable, false);
2232 static struct ftrace_ops *
2233 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2235 struct ftrace_ops *op;
2236 unsigned long ip = rec->ip;
2238 do_for_each_ftrace_op(op, ftrace_ops_list) {
2240 if (!op->trampoline)
2243 if (hash_contains_ip(ip, op->func_hash))
2245 } while_for_each_ftrace_op(op);
2250 static struct ftrace_ops *
2251 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2252 struct ftrace_ops *op)
2254 unsigned long ip = rec->ip;
2256 while_for_each_ftrace_op(op) {
2258 if (!op->trampoline)
2261 if (hash_contains_ip(ip, op->func_hash))
2268 static struct ftrace_ops *
2269 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2271 struct ftrace_ops *op;
2272 unsigned long ip = rec->ip;
2275 * Need to check removed ops first.
2276 * If they are being removed, and this rec has a tramp,
2277 * and this rec is in the ops list, then it would be the
2278 * one with the tramp.
2281 if (hash_contains_ip(ip, &removed_ops->old_hash))
2286 * Need to find the current trampoline for a rec.
2287 * Now, a trampoline is only attached to a rec if there
2288 * was a single 'ops' attached to it. But this can be called
2289 * when we are adding another op to the rec or removing the
2290 * current one. Thus, if the op is being added, we can
2291 * ignore it because it hasn't attached itself to the rec
2294 * If an ops is being modified (hooking to different functions)
2295 * then we don't care about the new functions that are being
2296 * added, just the old ones (that are probably being removed).
2298 * If we are adding an ops to a function that already is using
2299 * a trampoline, it needs to be removed (trampolines are only
2300 * for single ops connected), then an ops that is not being
2301 * modified also needs to be checked.
2303 do_for_each_ftrace_op(op, ftrace_ops_list) {
2305 if (!op->trampoline)
2309 * If the ops is being added, it hasn't gotten to
2310 * the point to be removed from this tree yet.
2312 if (op->flags & FTRACE_OPS_FL_ADDING)
2317 * If the ops is being modified and is in the old
2318 * hash, then it is probably being removed from this
2321 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2322 hash_contains_ip(ip, &op->old_hash))
2325 * If the ops is not being added or modified, and it's
2326 * in its normal filter hash, then this must be the one
2329 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2330 hash_contains_ip(ip, op->func_hash))
2333 } while_for_each_ftrace_op(op);
2338 static struct ftrace_ops *
2339 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2341 struct ftrace_ops *op;
2342 unsigned long ip = rec->ip;
2344 do_for_each_ftrace_op(op, ftrace_ops_list) {
2345 /* pass rec in as regs to have non-NULL val */
2346 if (hash_contains_ip(ip, op->func_hash))
2348 } while_for_each_ftrace_op(op);
2353 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
2354 /* Protected by rcu_tasks for reading, and direct_mutex for writing */
2355 static struct ftrace_hash *direct_functions = EMPTY_HASH;
2356 static DEFINE_MUTEX(direct_mutex);
2357 int ftrace_direct_func_count;
2360 * Search the direct_functions hash to see if the given instruction pointer
2361 * has a direct caller attached to it.
2363 unsigned long ftrace_find_rec_direct(unsigned long ip)
2365 struct ftrace_func_entry *entry;
2367 entry = __ftrace_lookup_ip(direct_functions, ip);
2371 return entry->direct;
2374 static void call_direct_funcs(unsigned long ip, unsigned long pip,
2375 struct ftrace_ops *ops, struct pt_regs *regs)
2379 addr = ftrace_find_rec_direct(ip);
2383 arch_ftrace_set_direct_caller(regs, addr);
2386 struct ftrace_ops direct_ops = {
2387 .func = call_direct_funcs,
2388 .flags = FTRACE_OPS_FL_IPMODIFY | FTRACE_OPS_FL_RECURSION_SAFE
2389 | FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
2390 | FTRACE_OPS_FL_PERMANENT,
2392 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
2395 * ftrace_get_addr_new - Get the call address to set to
2396 * @rec: The ftrace record descriptor
2398 * If the record has the FTRACE_FL_REGS set, that means that it
2399 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2400 * is not not set, then it wants to convert to the normal callback.
2402 * Returns the address of the trampoline to set to
2404 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2406 struct ftrace_ops *ops;
2409 if ((rec->flags & FTRACE_FL_DIRECT) &&
2410 (ftrace_rec_count(rec) == 1)) {
2411 addr = ftrace_find_rec_direct(rec->ip);
2417 /* Trampolines take precedence over regs */
2418 if (rec->flags & FTRACE_FL_TRAMP) {
2419 ops = ftrace_find_tramp_ops_new(rec);
2420 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2421 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2422 (void *)rec->ip, (void *)rec->ip, rec->flags);
2423 /* Ftrace is shutting down, return anything */
2424 return (unsigned long)FTRACE_ADDR;
2426 return ops->trampoline;
2429 if (rec->flags & FTRACE_FL_REGS)
2430 return (unsigned long)FTRACE_REGS_ADDR;
2432 return (unsigned long)FTRACE_ADDR;
2436 * ftrace_get_addr_curr - Get the call address that is already there
2437 * @rec: The ftrace record descriptor
2439 * The FTRACE_FL_REGS_EN is set when the record already points to
2440 * a function that saves all the regs. Basically the '_EN' version
2441 * represents the current state of the function.
2443 * Returns the address of the trampoline that is currently being called
2445 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2447 struct ftrace_ops *ops;
2450 /* Direct calls take precedence over trampolines */
2451 if (rec->flags & FTRACE_FL_DIRECT_EN) {
2452 addr = ftrace_find_rec_direct(rec->ip);
2458 /* Trampolines take precedence over regs */
2459 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2460 ops = ftrace_find_tramp_ops_curr(rec);
2461 if (FTRACE_WARN_ON(!ops)) {
2462 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2463 (void *)rec->ip, (void *)rec->ip);
2464 /* Ftrace is shutting down, return anything */
2465 return (unsigned long)FTRACE_ADDR;
2467 return ops->trampoline;
2470 if (rec->flags & FTRACE_FL_REGS_EN)
2471 return (unsigned long)FTRACE_REGS_ADDR;
2473 return (unsigned long)FTRACE_ADDR;
2477 __ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2479 unsigned long ftrace_old_addr;
2480 unsigned long ftrace_addr;
2483 ftrace_addr = ftrace_get_addr_new(rec);
2485 /* This needs to be done before we call ftrace_update_record */
2486 ftrace_old_addr = ftrace_get_addr_curr(rec);
2488 ret = ftrace_update_record(rec, enable);
2490 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2493 case FTRACE_UPDATE_IGNORE:
2496 case FTRACE_UPDATE_MAKE_CALL:
2497 ftrace_bug_type = FTRACE_BUG_CALL;
2498 return ftrace_make_call(rec, ftrace_addr);
2500 case FTRACE_UPDATE_MAKE_NOP:
2501 ftrace_bug_type = FTRACE_BUG_NOP;
2502 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2504 case FTRACE_UPDATE_MODIFY_CALL:
2505 ftrace_bug_type = FTRACE_BUG_UPDATE;
2506 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2509 return -1; /* unknown ftrace bug */
2512 void __weak ftrace_replace_code(int mod_flags)
2514 struct dyn_ftrace *rec;
2515 struct ftrace_page *pg;
2516 bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2517 int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2520 if (unlikely(ftrace_disabled))
2523 do_for_each_ftrace_rec(pg, rec) {
2525 if (rec->flags & FTRACE_FL_DISABLED)
2528 failed = __ftrace_replace_code(rec, enable);
2530 ftrace_bug(failed, rec);
2531 /* Stop processing */
2536 } while_for_each_ftrace_rec();
2539 struct ftrace_rec_iter {
2540 struct ftrace_page *pg;
2545 * ftrace_rec_iter_start, start up iterating over traced functions
2547 * Returns an iterator handle that is used to iterate over all
2548 * the records that represent address locations where functions
2551 * May return NULL if no records are available.
2553 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2556 * We only use a single iterator.
2557 * Protected by the ftrace_lock mutex.
2559 static struct ftrace_rec_iter ftrace_rec_iter;
2560 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2562 iter->pg = ftrace_pages_start;
2565 /* Could have empty pages */
2566 while (iter->pg && !iter->pg->index)
2567 iter->pg = iter->pg->next;
2576 * ftrace_rec_iter_next, get the next record to process.
2577 * @iter: The handle to the iterator.
2579 * Returns the next iterator after the given iterator @iter.
2581 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2585 if (iter->index >= iter->pg->index) {
2586 iter->pg = iter->pg->next;
2589 /* Could have empty pages */
2590 while (iter->pg && !iter->pg->index)
2591 iter->pg = iter->pg->next;
2601 * ftrace_rec_iter_record, get the record at the iterator location
2602 * @iter: The current iterator location
2604 * Returns the record that the current @iter is at.
2606 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2608 return &iter->pg->records[iter->index];
2612 ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
2616 if (unlikely(ftrace_disabled))
2619 ret = ftrace_init_nop(mod, rec);
2621 ftrace_bug_type = FTRACE_BUG_INIT;
2622 ftrace_bug(ret, rec);
2629 * archs can override this function if they must do something
2630 * before the modifying code is performed.
2632 int __weak ftrace_arch_code_modify_prepare(void)
2638 * archs can override this function if they must do something
2639 * after the modifying code is performed.
2641 int __weak ftrace_arch_code_modify_post_process(void)
2646 void ftrace_modify_all_code(int command)
2648 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2652 if (command & FTRACE_MAY_SLEEP)
2653 mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2656 * If the ftrace_caller calls a ftrace_ops func directly,
2657 * we need to make sure that it only traces functions it
2658 * expects to trace. When doing the switch of functions,
2659 * we need to update to the ftrace_ops_list_func first
2660 * before the transition between old and new calls are set,
2661 * as the ftrace_ops_list_func will check the ops hashes
2662 * to make sure the ops are having the right functions
2666 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2667 if (FTRACE_WARN_ON(err))
2671 if (command & FTRACE_UPDATE_CALLS)
2672 ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2673 else if (command & FTRACE_DISABLE_CALLS)
2674 ftrace_replace_code(mod_flags);
2676 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2677 function_trace_op = set_function_trace_op;
2679 /* If irqs are disabled, we are in stop machine */
2680 if (!irqs_disabled())
2681 smp_call_function(ftrace_sync_ipi, NULL, 1);
2682 err = ftrace_update_ftrace_func(ftrace_trace_function);
2683 if (FTRACE_WARN_ON(err))
2687 if (command & FTRACE_START_FUNC_RET)
2688 err = ftrace_enable_ftrace_graph_caller();
2689 else if (command & FTRACE_STOP_FUNC_RET)
2690 err = ftrace_disable_ftrace_graph_caller();
2691 FTRACE_WARN_ON(err);
2694 static int __ftrace_modify_code(void *data)
2696 int *command = data;
2698 ftrace_modify_all_code(*command);
2704 * ftrace_run_stop_machine, go back to the stop machine method
2705 * @command: The command to tell ftrace what to do
2707 * If an arch needs to fall back to the stop machine method, the
2708 * it can call this function.
2710 void ftrace_run_stop_machine(int command)
2712 stop_machine(__ftrace_modify_code, &command, NULL);
2716 * arch_ftrace_update_code, modify the code to trace or not trace
2717 * @command: The command that needs to be done
2719 * Archs can override this function if it does not need to
2720 * run stop_machine() to modify code.
2722 void __weak arch_ftrace_update_code(int command)
2724 ftrace_run_stop_machine(command);
2727 static void ftrace_run_update_code(int command)
2731 ret = ftrace_arch_code_modify_prepare();
2732 FTRACE_WARN_ON(ret);
2737 * By default we use stop_machine() to modify the code.
2738 * But archs can do what ever they want as long as it
2739 * is safe. The stop_machine() is the safest, but also
2740 * produces the most overhead.
2742 arch_ftrace_update_code(command);
2744 ret = ftrace_arch_code_modify_post_process();
2745 FTRACE_WARN_ON(ret);
2748 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2749 struct ftrace_ops_hash *old_hash)
2751 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2752 ops->old_hash.filter_hash = old_hash->filter_hash;
2753 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2754 ftrace_run_update_code(command);
2755 ops->old_hash.filter_hash = NULL;
2756 ops->old_hash.notrace_hash = NULL;
2757 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2760 static ftrace_func_t saved_ftrace_func;
2761 static int ftrace_start_up;
2763 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2767 static void ftrace_startup_enable(int command)
2769 if (saved_ftrace_func != ftrace_trace_function) {
2770 saved_ftrace_func = ftrace_trace_function;
2771 command |= FTRACE_UPDATE_TRACE_FUNC;
2774 if (!command || !ftrace_enabled)
2777 ftrace_run_update_code(command);
2780 static void ftrace_startup_all(int command)
2782 update_all_ops = true;
2783 ftrace_startup_enable(command);
2784 update_all_ops = false;
2787 int ftrace_startup(struct ftrace_ops *ops, int command)
2791 if (unlikely(ftrace_disabled))
2794 ret = __register_ftrace_function(ops);
2801 * Note that ftrace probes uses this to start up
2802 * and modify functions it will probe. But we still
2803 * set the ADDING flag for modification, as probes
2804 * do not have trampolines. If they add them in the
2805 * future, then the probes will need to distinguish
2806 * between adding and updating probes.
2808 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2810 ret = ftrace_hash_ipmodify_enable(ops);
2812 /* Rollback registration process */
2813 __unregister_ftrace_function(ops);
2815 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2819 if (ftrace_hash_rec_enable(ops, 1))
2820 command |= FTRACE_UPDATE_CALLS;
2822 ftrace_startup_enable(command);
2824 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2829 int ftrace_shutdown(struct ftrace_ops *ops, int command)
2833 if (unlikely(ftrace_disabled))
2836 ret = __unregister_ftrace_function(ops);
2842 * Just warn in case of unbalance, no need to kill ftrace, it's not
2843 * critical but the ftrace_call callers may be never nopped again after
2844 * further ftrace uses.
2846 WARN_ON_ONCE(ftrace_start_up < 0);
2848 /* Disabling ipmodify never fails */
2849 ftrace_hash_ipmodify_disable(ops);
2851 if (ftrace_hash_rec_disable(ops, 1))
2852 command |= FTRACE_UPDATE_CALLS;
2854 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2856 if (saved_ftrace_func != ftrace_trace_function) {
2857 saved_ftrace_func = ftrace_trace_function;
2858 command |= FTRACE_UPDATE_TRACE_FUNC;
2861 if (!command || !ftrace_enabled) {
2863 * If these are dynamic or per_cpu ops, they still
2864 * need their data freed. Since, function tracing is
2865 * not currently active, we can just free them
2866 * without synchronizing all CPUs.
2868 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2875 * If the ops uses a trampoline, then it needs to be
2876 * tested first on update.
2878 ops->flags |= FTRACE_OPS_FL_REMOVING;
2881 /* The trampoline logic checks the old hashes */
2882 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2883 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2885 ftrace_run_update_code(command);
2888 * If there's no more ops registered with ftrace, run a
2889 * sanity check to make sure all rec flags are cleared.
2891 if (rcu_dereference_protected(ftrace_ops_list,
2892 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
2893 struct ftrace_page *pg;
2894 struct dyn_ftrace *rec;
2896 do_for_each_ftrace_rec(pg, rec) {
2897 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
2898 pr_warn(" %pS flags:%lx\n",
2899 (void *)rec->ip, rec->flags);
2900 } while_for_each_ftrace_rec();
2903 ops->old_hash.filter_hash = NULL;
2904 ops->old_hash.notrace_hash = NULL;
2907 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2910 * Dynamic ops may be freed, we must make sure that all
2911 * callers are done before leaving this function.
2912 * The same goes for freeing the per_cpu data of the per_cpu
2915 if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
2917 * We need to do a hard force of sched synchronization.
2918 * This is because we use preempt_disable() to do RCU, but
2919 * the function tracers can be called where RCU is not watching
2920 * (like before user_exit()). We can not rely on the RCU
2921 * infrastructure to do the synchronization, thus we must do it
2924 synchronize_rcu_tasks_rude();
2927 * When the kernel is preeptive, tasks can be preempted
2928 * while on a ftrace trampoline. Just scheduling a task on
2929 * a CPU is not good enough to flush them. Calling
2930 * synchornize_rcu_tasks() will wait for those tasks to
2931 * execute and either schedule voluntarily or enter user space.
2933 if (IS_ENABLED(CONFIG_PREEMPTION))
2934 synchronize_rcu_tasks();
2937 arch_ftrace_trampoline_free(ops);
2943 static void ftrace_startup_sysctl(void)
2947 if (unlikely(ftrace_disabled))
2950 /* Force update next time */
2951 saved_ftrace_func = NULL;
2952 /* ftrace_start_up is true if we want ftrace running */
2953 if (ftrace_start_up) {
2954 command = FTRACE_UPDATE_CALLS;
2955 if (ftrace_graph_active)
2956 command |= FTRACE_START_FUNC_RET;
2957 ftrace_startup_enable(command);
2961 static void ftrace_shutdown_sysctl(void)
2965 if (unlikely(ftrace_disabled))
2968 /* ftrace_start_up is true if ftrace is running */
2969 if (ftrace_start_up) {
2970 command = FTRACE_DISABLE_CALLS;
2971 if (ftrace_graph_active)
2972 command |= FTRACE_STOP_FUNC_RET;
2973 ftrace_run_update_code(command);
2977 static u64 ftrace_update_time;
2978 unsigned long ftrace_update_tot_cnt;
2979 unsigned long ftrace_number_of_pages;
2980 unsigned long ftrace_number_of_groups;
2982 static inline int ops_traces_mod(struct ftrace_ops *ops)
2985 * Filter_hash being empty will default to trace module.
2986 * But notrace hash requires a test of individual module functions.
2988 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
2989 ftrace_hash_empty(ops->func_hash->notrace_hash);
2993 * Check if the current ops references the record.
2995 * If the ops traces all functions, then it was already accounted for.
2996 * If the ops does not trace the current record function, skip it.
2997 * If the ops ignores the function via notrace filter, skip it.
3000 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3002 /* If ops isn't enabled, ignore it */
3003 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
3006 /* If ops traces all then it includes this function */
3007 if (ops_traces_mod(ops))
3010 /* The function must be in the filter */
3011 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
3012 !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
3015 /* If in notrace hash, we ignore it too */
3016 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
3022 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
3024 struct ftrace_page *pg;
3025 struct dyn_ftrace *p;
3027 unsigned long update_cnt = 0;
3028 unsigned long rec_flags = 0;
3031 start = ftrace_now(raw_smp_processor_id());
3034 * When a module is loaded, this function is called to convert
3035 * the calls to mcount in its text to nops, and also to create
3036 * an entry in the ftrace data. Now, if ftrace is activated
3037 * after this call, but before the module sets its text to
3038 * read-only, the modification of enabling ftrace can fail if
3039 * the read-only is done while ftrace is converting the calls.
3040 * To prevent this, the module's records are set as disabled
3041 * and will be enabled after the call to set the module's text
3045 rec_flags |= FTRACE_FL_DISABLED;
3047 for (pg = new_pgs; pg; pg = pg->next) {
3049 for (i = 0; i < pg->index; i++) {
3051 /* If something went wrong, bail without enabling anything */
3052 if (unlikely(ftrace_disabled))
3055 p = &pg->records[i];
3056 p->flags = rec_flags;
3059 * Do the initial record conversion from mcount jump
3060 * to the NOP instructions.
3062 if (!__is_defined(CC_USING_NOP_MCOUNT) &&
3063 !ftrace_nop_initialize(mod, p))
3070 stop = ftrace_now(raw_smp_processor_id());
3071 ftrace_update_time = stop - start;
3072 ftrace_update_tot_cnt += update_cnt;
3077 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3082 if (WARN_ON(!count))
3085 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
3088 * We want to fill as much as possible. No more than a page
3091 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
3095 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3098 /* if we can't allocate this size, try something smaller */
3105 ftrace_number_of_pages += 1 << order;
3106 ftrace_number_of_groups++;
3108 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3117 static struct ftrace_page *
3118 ftrace_allocate_pages(unsigned long num_to_init)
3120 struct ftrace_page *start_pg;
3121 struct ftrace_page *pg;
3128 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3133 * Try to allocate as much as possible in one continues
3134 * location that fills in all of the space. We want to
3135 * waste as little space as possible.
3138 cnt = ftrace_allocate_records(pg, num_to_init);
3146 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3158 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3159 free_pages((unsigned long)pg->records, order);
3160 start_pg = pg->next;
3163 ftrace_number_of_pages -= 1 << order;
3164 ftrace_number_of_groups--;
3166 pr_info("ftrace: FAILED to allocate memory for functions\n");
3170 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3172 struct ftrace_iterator {
3176 struct ftrace_page *pg;
3177 struct dyn_ftrace *func;
3178 struct ftrace_func_probe *probe;
3179 struct ftrace_func_entry *probe_entry;
3180 struct trace_parser parser;
3181 struct ftrace_hash *hash;
3182 struct ftrace_ops *ops;
3183 struct trace_array *tr;
3184 struct list_head *mod_list;
3191 t_probe_next(struct seq_file *m, loff_t *pos)
3193 struct ftrace_iterator *iter = m->private;
3194 struct trace_array *tr = iter->ops->private;
3195 struct list_head *func_probes;
3196 struct ftrace_hash *hash;
3197 struct list_head *next;
3198 struct hlist_node *hnd = NULL;
3199 struct hlist_head *hhd;
3208 func_probes = &tr->func_probes;
3209 if (list_empty(func_probes))
3213 next = func_probes->next;
3214 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3217 if (iter->probe_entry)
3218 hnd = &iter->probe_entry->hlist;
3220 hash = iter->probe->ops.func_hash->filter_hash;
3223 * A probe being registered may temporarily have an empty hash
3224 * and it's at the end of the func_probes list.
3226 if (!hash || hash == EMPTY_HASH)
3229 size = 1 << hash->size_bits;
3232 if (iter->pidx >= size) {
3233 if (iter->probe->list.next == func_probes)
3235 next = iter->probe->list.next;
3236 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3237 hash = iter->probe->ops.func_hash->filter_hash;
3238 size = 1 << hash->size_bits;
3242 hhd = &hash->buckets[iter->pidx];
3244 if (hlist_empty(hhd)) {
3260 if (WARN_ON_ONCE(!hnd))
3263 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3268 static void *t_probe_start(struct seq_file *m, loff_t *pos)
3270 struct ftrace_iterator *iter = m->private;
3274 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3277 if (iter->mod_pos > *pos)
3281 iter->probe_entry = NULL;
3283 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3284 p = t_probe_next(m, &l);
3291 /* Only set this if we have an item */
3292 iter->flags |= FTRACE_ITER_PROBE;
3298 t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3300 struct ftrace_func_entry *probe_entry;
3301 struct ftrace_probe_ops *probe_ops;
3302 struct ftrace_func_probe *probe;
3304 probe = iter->probe;
3305 probe_entry = iter->probe_entry;
3307 if (WARN_ON_ONCE(!probe || !probe_entry))
3310 probe_ops = probe->probe_ops;
3312 if (probe_ops->print)
3313 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3315 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3316 (void *)probe_ops->func);
3322 t_mod_next(struct seq_file *m, loff_t *pos)
3324 struct ftrace_iterator *iter = m->private;
3325 struct trace_array *tr = iter->tr;
3330 iter->mod_list = iter->mod_list->next;
3332 if (iter->mod_list == &tr->mod_trace ||
3333 iter->mod_list == &tr->mod_notrace) {
3334 iter->flags &= ~FTRACE_ITER_MOD;
3338 iter->mod_pos = *pos;
3343 static void *t_mod_start(struct seq_file *m, loff_t *pos)
3345 struct ftrace_iterator *iter = m->private;
3349 if (iter->func_pos > *pos)
3352 iter->mod_pos = iter->func_pos;
3354 /* probes are only available if tr is set */
3358 for (l = 0; l <= (*pos - iter->func_pos); ) {
3359 p = t_mod_next(m, &l);
3364 iter->flags &= ~FTRACE_ITER_MOD;
3365 return t_probe_start(m, pos);
3368 /* Only set this if we have an item */
3369 iter->flags |= FTRACE_ITER_MOD;
3375 t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3377 struct ftrace_mod_load *ftrace_mod;
3378 struct trace_array *tr = iter->tr;
3380 if (WARN_ON_ONCE(!iter->mod_list) ||
3381 iter->mod_list == &tr->mod_trace ||
3382 iter->mod_list == &tr->mod_notrace)
3385 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3387 if (ftrace_mod->func)
3388 seq_printf(m, "%s", ftrace_mod->func);
3392 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3398 t_func_next(struct seq_file *m, loff_t *pos)
3400 struct ftrace_iterator *iter = m->private;
3401 struct dyn_ftrace *rec = NULL;
3406 if (iter->idx >= iter->pg->index) {
3407 if (iter->pg->next) {
3408 iter->pg = iter->pg->next;
3413 rec = &iter->pg->records[iter->idx++];
3414 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3415 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3417 ((iter->flags & FTRACE_ITER_ENABLED) &&
3418 !(rec->flags & FTRACE_FL_ENABLED))) {
3428 iter->pos = iter->func_pos = *pos;
3435 t_next(struct seq_file *m, void *v, loff_t *pos)
3437 struct ftrace_iterator *iter = m->private;
3438 loff_t l = *pos; /* t_probe_start() must use original pos */
3441 if (unlikely(ftrace_disabled))
3444 if (iter->flags & FTRACE_ITER_PROBE)
3445 return t_probe_next(m, pos);
3447 if (iter->flags & FTRACE_ITER_MOD)
3448 return t_mod_next(m, pos);
3450 if (iter->flags & FTRACE_ITER_PRINTALL) {
3451 /* next must increment pos, and t_probe_start does not */
3453 return t_mod_start(m, &l);
3456 ret = t_func_next(m, pos);
3459 return t_mod_start(m, &l);
3464 static void reset_iter_read(struct ftrace_iterator *iter)
3468 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3471 static void *t_start(struct seq_file *m, loff_t *pos)
3473 struct ftrace_iterator *iter = m->private;
3477 mutex_lock(&ftrace_lock);
3479 if (unlikely(ftrace_disabled))
3483 * If an lseek was done, then reset and start from beginning.
3485 if (*pos < iter->pos)
3486 reset_iter_read(iter);
3489 * For set_ftrace_filter reading, if we have the filter
3490 * off, we can short cut and just print out that all
3491 * functions are enabled.
3493 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3494 ftrace_hash_empty(iter->hash)) {
3495 iter->func_pos = 1; /* Account for the message */
3497 return t_mod_start(m, pos);
3498 iter->flags |= FTRACE_ITER_PRINTALL;
3499 /* reset in case of seek/pread */
3500 iter->flags &= ~FTRACE_ITER_PROBE;
3504 if (iter->flags & FTRACE_ITER_MOD)
3505 return t_mod_start(m, pos);
3508 * Unfortunately, we need to restart at ftrace_pages_start
3509 * every time we let go of the ftrace_mutex. This is because
3510 * those pointers can change without the lock.
3512 iter->pg = ftrace_pages_start;
3514 for (l = 0; l <= *pos; ) {
3515 p = t_func_next(m, &l);
3521 return t_mod_start(m, pos);
3526 static void t_stop(struct seq_file *m, void *p)
3528 mutex_unlock(&ftrace_lock);
3532 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3537 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3538 struct dyn_ftrace *rec)
3542 ptr = arch_ftrace_trampoline_func(ops, rec);
3544 seq_printf(m, " ->%pS", ptr);
3547 static int t_show(struct seq_file *m, void *v)
3549 struct ftrace_iterator *iter = m->private;
3550 struct dyn_ftrace *rec;
3552 if (iter->flags & FTRACE_ITER_PROBE)
3553 return t_probe_show(m, iter);
3555 if (iter->flags & FTRACE_ITER_MOD)
3556 return t_mod_show(m, iter);
3558 if (iter->flags & FTRACE_ITER_PRINTALL) {
3559 if (iter->flags & FTRACE_ITER_NOTRACE)
3560 seq_puts(m, "#### no functions disabled ####\n");
3562 seq_puts(m, "#### all functions enabled ####\n");
3571 seq_printf(m, "%ps", (void *)rec->ip);
3572 if (iter->flags & FTRACE_ITER_ENABLED) {
3573 struct ftrace_ops *ops;
3575 seq_printf(m, " (%ld)%s%s%s",
3576 ftrace_rec_count(rec),
3577 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3578 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ",
3579 rec->flags & FTRACE_FL_DIRECT ? " D" : " ");
3580 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3581 ops = ftrace_find_tramp_ops_any(rec);
3584 seq_printf(m, "\ttramp: %pS (%pS)",
3585 (void *)ops->trampoline,
3587 add_trampoline_func(m, ops, rec);
3588 ops = ftrace_find_tramp_ops_next(rec, ops);
3591 seq_puts(m, "\ttramp: ERROR!");
3593 add_trampoline_func(m, NULL, rec);
3595 if (rec->flags & FTRACE_FL_DIRECT) {
3596 unsigned long direct;
3598 direct = ftrace_find_rec_direct(rec->ip);
3600 seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
3609 static const struct seq_operations show_ftrace_seq_ops = {
3617 ftrace_avail_open(struct inode *inode, struct file *file)
3619 struct ftrace_iterator *iter;
3622 ret = security_locked_down(LOCKDOWN_TRACEFS);
3626 if (unlikely(ftrace_disabled))
3629 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3633 iter->pg = ftrace_pages_start;
3634 iter->ops = &global_ops;
3640 ftrace_enabled_open(struct inode *inode, struct file *file)
3642 struct ftrace_iterator *iter;
3645 * This shows us what functions are currently being
3646 * traced and by what. Not sure if we want lockdown
3647 * to hide such critical information for an admin.
3648 * Although, perhaps it can show information we don't
3649 * want people to see, but if something is tracing
3650 * something, we probably want to know about it.
3653 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3657 iter->pg = ftrace_pages_start;
3658 iter->flags = FTRACE_ITER_ENABLED;
3659 iter->ops = &global_ops;
3665 * ftrace_regex_open - initialize function tracer filter files
3666 * @ops: The ftrace_ops that hold the hash filters
3667 * @flag: The type of filter to process
3668 * @inode: The inode, usually passed in to your open routine
3669 * @file: The file, usually passed in to your open routine
3671 * ftrace_regex_open() initializes the filter files for the
3672 * @ops. Depending on @flag it may process the filter hash or
3673 * the notrace hash of @ops. With this called from the open
3674 * routine, you can use ftrace_filter_write() for the write
3675 * routine if @flag has FTRACE_ITER_FILTER set, or
3676 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3677 * tracing_lseek() should be used as the lseek routine, and
3678 * release must call ftrace_regex_release().
3681 ftrace_regex_open(struct ftrace_ops *ops, int flag,
3682 struct inode *inode, struct file *file)
3684 struct ftrace_iterator *iter;
3685 struct ftrace_hash *hash;
3686 struct list_head *mod_head;
3687 struct trace_array *tr = ops->private;
3690 ftrace_ops_init(ops);
3692 if (unlikely(ftrace_disabled))
3695 if (tracing_check_open_get_tr(tr))
3698 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3702 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
3709 mutex_lock(&ops->func_hash->regex_lock);
3711 if (flag & FTRACE_ITER_NOTRACE) {
3712 hash = ops->func_hash->notrace_hash;
3713 mod_head = tr ? &tr->mod_notrace : NULL;
3715 hash = ops->func_hash->filter_hash;
3716 mod_head = tr ? &tr->mod_trace : NULL;
3719 iter->mod_list = mod_head;
3721 if (file->f_mode & FMODE_WRITE) {
3722 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3724 if (file->f_flags & O_TRUNC) {
3725 iter->hash = alloc_ftrace_hash(size_bits);
3726 clear_ftrace_mod_list(mod_head);
3728 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3732 trace_parser_put(&iter->parser);
3740 if (file->f_mode & FMODE_READ) {
3741 iter->pg = ftrace_pages_start;
3743 ret = seq_open(file, &show_ftrace_seq_ops);
3745 struct seq_file *m = file->private_data;
3749 free_ftrace_hash(iter->hash);
3750 trace_parser_put(&iter->parser);
3753 file->private_data = iter;
3756 mutex_unlock(&ops->func_hash->regex_lock);
3762 trace_array_put(tr);
3769 ftrace_filter_open(struct inode *inode, struct file *file)
3771 struct ftrace_ops *ops = inode->i_private;
3773 /* Checks for tracefs lockdown */
3774 return ftrace_regex_open(ops,
3775 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3780 ftrace_notrace_open(struct inode *inode, struct file *file)
3782 struct ftrace_ops *ops = inode->i_private;
3784 /* Checks for tracefs lockdown */
3785 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3789 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3790 struct ftrace_glob {
3797 * If symbols in an architecture don't correspond exactly to the user-visible
3798 * name of what they represent, it is possible to define this function to
3799 * perform the necessary adjustments.
3801 char * __weak arch_ftrace_match_adjust(char *str, const char *search)
3806 static int ftrace_match(char *str, struct ftrace_glob *g)
3811 str = arch_ftrace_match_adjust(str, g->search);
3815 if (strcmp(str, g->search) == 0)
3818 case MATCH_FRONT_ONLY:
3819 if (strncmp(str, g->search, g->len) == 0)
3822 case MATCH_MIDDLE_ONLY:
3823 if (strstr(str, g->search))
3826 case MATCH_END_ONLY:
3828 if (slen >= g->len &&
3829 memcmp(str + slen - g->len, g->search, g->len) == 0)
3833 if (glob_match(g->search, str))
3842 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3844 struct ftrace_func_entry *entry;
3847 entry = ftrace_lookup_ip(hash, rec->ip);
3849 /* Do nothing if it doesn't exist */
3853 free_hash_entry(hash, entry);
3855 /* Do nothing if it exists */
3859 ret = add_hash_entry(hash, rec->ip);
3865 add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
3868 long index = simple_strtoul(func_g->search, NULL, 0);
3869 struct ftrace_page *pg;
3870 struct dyn_ftrace *rec;
3872 /* The index starts at 1 */
3876 do_for_each_ftrace_rec(pg, rec) {
3877 if (pg->index <= index) {
3879 /* this is a double loop, break goes to the next page */
3882 rec = &pg->records[index];
3883 enter_record(hash, rec, clear_filter);
3885 } while_for_each_ftrace_rec();
3890 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3891 struct ftrace_glob *mod_g, int exclude_mod)
3893 char str[KSYM_SYMBOL_LEN];
3896 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3899 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3901 /* blank module name to match all modules */
3903 /* blank module globbing: modname xor exclude_mod */
3904 if (!exclude_mod != !modname)
3910 * exclude_mod is set to trace everything but the given
3911 * module. If it is set and the module matches, then
3912 * return 0. If it is not set, and the module doesn't match
3913 * also return 0. Otherwise, check the function to see if
3916 if (!mod_matches == !exclude_mod)
3919 /* blank search means to match all funcs in the mod */
3924 return ftrace_match(str, func_g);
3928 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
3930 struct ftrace_page *pg;
3931 struct dyn_ftrace *rec;
3932 struct ftrace_glob func_g = { .type = MATCH_FULL };
3933 struct ftrace_glob mod_g = { .type = MATCH_FULL };
3934 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
3935 int exclude_mod = 0;
3938 int clear_filter = 0;
3941 func_g.type = filter_parse_regex(func, len, &func_g.search,
3943 func_g.len = strlen(func_g.search);
3947 mod_g.type = filter_parse_regex(mod, strlen(mod),
3948 &mod_g.search, &exclude_mod);
3949 mod_g.len = strlen(mod_g.search);
3952 mutex_lock(&ftrace_lock);
3954 if (unlikely(ftrace_disabled))
3957 if (func_g.type == MATCH_INDEX) {
3958 found = add_rec_by_index(hash, &func_g, clear_filter);
3962 do_for_each_ftrace_rec(pg, rec) {
3964 if (rec->flags & FTRACE_FL_DISABLED)
3967 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
3968 ret = enter_record(hash, rec, clear_filter);
3975 } while_for_each_ftrace_rec();
3977 mutex_unlock(&ftrace_lock);
3983 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
3985 return match_records(hash, buff, len, NULL);
3988 static void ftrace_ops_update_code(struct ftrace_ops *ops,
3989 struct ftrace_ops_hash *old_hash)
3991 struct ftrace_ops *op;
3993 if (!ftrace_enabled)
3996 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
3997 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4002 * If this is the shared global_ops filter, then we need to
4003 * check if there is another ops that shares it, is enabled.
4004 * If so, we still need to run the modify code.
4006 if (ops->func_hash != &global_ops.local_hash)
4009 do_for_each_ftrace_op(op, ftrace_ops_list) {
4010 if (op->func_hash == &global_ops.local_hash &&
4011 op->flags & FTRACE_OPS_FL_ENABLED) {
4012 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4013 /* Only need to do this once */
4016 } while_for_each_ftrace_op(op);
4019 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
4020 struct ftrace_hash **orig_hash,
4021 struct ftrace_hash *hash,
4024 struct ftrace_ops_hash old_hash_ops;
4025 struct ftrace_hash *old_hash;
4028 old_hash = *orig_hash;
4029 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4030 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4031 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4033 ftrace_ops_update_code(ops, &old_hash_ops);
4034 free_ftrace_hash_rcu(old_hash);
4039 static bool module_exists(const char *module)
4041 /* All modules have the symbol __this_module */
4042 static const char this_mod[] = "__this_module";
4043 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
4047 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
4049 if (n > sizeof(modname) - 1)
4052 val = module_kallsyms_lookup_name(modname);
4056 static int cache_mod(struct trace_array *tr,
4057 const char *func, char *module, int enable)
4059 struct ftrace_mod_load *ftrace_mod, *n;
4060 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4063 mutex_lock(&ftrace_lock);
4065 /* We do not cache inverse filters */
4066 if (func[0] == '!') {
4070 /* Look to remove this hash */
4071 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4072 if (strcmp(ftrace_mod->module, module) != 0)
4075 /* no func matches all */
4076 if (strcmp(func, "*") == 0 ||
4077 (ftrace_mod->func &&
4078 strcmp(ftrace_mod->func, func) == 0)) {
4080 free_ftrace_mod(ftrace_mod);
4088 /* We only care about modules that have not been loaded yet */
4089 if (module_exists(module))
4092 /* Save this string off, and execute it when the module is loaded */
4093 ret = ftrace_add_mod(tr, func, module, enable);
4095 mutex_unlock(&ftrace_lock);
4101 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4102 int reset, int enable);
4104 #ifdef CONFIG_MODULES
4105 static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4106 char *mod, bool enable)
4108 struct ftrace_mod_load *ftrace_mod, *n;
4109 struct ftrace_hash **orig_hash, *new_hash;
4110 LIST_HEAD(process_mods);
4114 mutex_lock(&ops->func_hash->regex_lock);
4117 orig_hash = &ops->func_hash->filter_hash;
4119 orig_hash = &ops->func_hash->notrace_hash;
4121 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4124 goto out; /* warn? */
4126 mutex_lock(&ftrace_lock);
4128 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4130 if (strcmp(ftrace_mod->module, mod) != 0)
4133 if (ftrace_mod->func)
4134 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4136 func = kstrdup("*", GFP_KERNEL);
4138 if (!func) /* warn? */
4141 list_del(&ftrace_mod->list);
4142 list_add(&ftrace_mod->list, &process_mods);
4144 /* Use the newly allocated func, as it may be "*" */
4145 kfree(ftrace_mod->func);
4146 ftrace_mod->func = func;
4149 mutex_unlock(&ftrace_lock);
4151 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4153 func = ftrace_mod->func;
4155 /* Grabs ftrace_lock, which is why we have this extra step */
4156 match_records(new_hash, func, strlen(func), mod);
4157 free_ftrace_mod(ftrace_mod);
4160 if (enable && list_empty(head))
4161 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4163 mutex_lock(&ftrace_lock);
4165 ret = ftrace_hash_move_and_update_ops(ops, orig_hash,
4167 mutex_unlock(&ftrace_lock);
4170 mutex_unlock(&ops->func_hash->regex_lock);
4172 free_ftrace_hash(new_hash);
4175 static void process_cached_mods(const char *mod_name)
4177 struct trace_array *tr;
4180 mod = kstrdup(mod_name, GFP_KERNEL);
4184 mutex_lock(&trace_types_lock);
4185 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4186 if (!list_empty(&tr->mod_trace))
4187 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4188 if (!list_empty(&tr->mod_notrace))
4189 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4191 mutex_unlock(&trace_types_lock);
4198 * We register the module command as a template to show others how
4199 * to register the a command as well.
4203 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4204 char *func_orig, char *cmd, char *module, int enable)
4209 /* match_records() modifies func, and we need the original */
4210 func = kstrdup(func_orig, GFP_KERNEL);
4215 * cmd == 'mod' because we only registered this func
4216 * for the 'mod' ftrace_func_command.
4217 * But if you register one func with multiple commands,
4218 * you can tell which command was used by the cmd
4221 ret = match_records(hash, func, strlen(func), module);
4225 return cache_mod(tr, func_orig, module, enable);
4231 static struct ftrace_func_command ftrace_mod_cmd = {
4233 .func = ftrace_mod_callback,
4236 static int __init ftrace_mod_cmd_init(void)
4238 return register_ftrace_command(&ftrace_mod_cmd);
4240 core_initcall(ftrace_mod_cmd_init);
4242 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4243 struct ftrace_ops *op, struct pt_regs *pt_regs)
4245 struct ftrace_probe_ops *probe_ops;
4246 struct ftrace_func_probe *probe;
4248 probe = container_of(op, struct ftrace_func_probe, ops);
4249 probe_ops = probe->probe_ops;
4252 * Disable preemption for these calls to prevent a RCU grace
4253 * period. This syncs the hash iteration and freeing of items
4254 * on the hash. rcu_read_lock is too dangerous here.
4256 preempt_disable_notrace();
4257 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4258 preempt_enable_notrace();
4261 struct ftrace_func_map {
4262 struct ftrace_func_entry entry;
4266 struct ftrace_func_mapper {
4267 struct ftrace_hash hash;
4271 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4273 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4275 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4277 struct ftrace_hash *hash;
4280 * The mapper is simply a ftrace_hash, but since the entries
4281 * in the hash are not ftrace_func_entry type, we define it
4282 * as a separate structure.
4284 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4285 return (struct ftrace_func_mapper *)hash;
4289 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4290 * @mapper: The mapper that has the ip maps
4291 * @ip: the instruction pointer to find the data for
4293 * Returns the data mapped to @ip if found otherwise NULL. The return
4294 * is actually the address of the mapper data pointer. The address is
4295 * returned for use cases where the data is no bigger than a long, and
4296 * the user can use the data pointer as its data instead of having to
4297 * allocate more memory for the reference.
4299 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4302 struct ftrace_func_entry *entry;
4303 struct ftrace_func_map *map;
4305 entry = ftrace_lookup_ip(&mapper->hash, ip);
4309 map = (struct ftrace_func_map *)entry;
4314 * ftrace_func_mapper_add_ip - Map some data to an ip
4315 * @mapper: The mapper that has the ip maps
4316 * @ip: The instruction pointer address to map @data to
4317 * @data: The data to map to @ip
4319 * Returns 0 on succes otherwise an error.
4321 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4322 unsigned long ip, void *data)
4324 struct ftrace_func_entry *entry;
4325 struct ftrace_func_map *map;
4327 entry = ftrace_lookup_ip(&mapper->hash, ip);
4331 map = kmalloc(sizeof(*map), GFP_KERNEL);
4338 __add_hash_entry(&mapper->hash, &map->entry);
4344 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4345 * @mapper: The mapper that has the ip maps
4346 * @ip: The instruction pointer address to remove the data from
4348 * Returns the data if it is found, otherwise NULL.
4349 * Note, if the data pointer is used as the data itself, (see
4350 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4351 * if the data pointer was set to zero.
4353 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4356 struct ftrace_func_entry *entry;
4357 struct ftrace_func_map *map;
4360 entry = ftrace_lookup_ip(&mapper->hash, ip);
4364 map = (struct ftrace_func_map *)entry;
4367 remove_hash_entry(&mapper->hash, entry);
4374 * free_ftrace_func_mapper - free a mapping of ips and data
4375 * @mapper: The mapper that has the ip maps
4376 * @free_func: A function to be called on each data item.
4378 * This is used to free the function mapper. The @free_func is optional
4379 * and can be used if the data needs to be freed as well.
4381 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4382 ftrace_mapper_func free_func)
4384 struct ftrace_func_entry *entry;
4385 struct ftrace_func_map *map;
4386 struct hlist_head *hhd;
4392 if (free_func && mapper->hash.count) {
4393 size = 1 << mapper->hash.size_bits;
4394 for (i = 0; i < size; i++) {
4395 hhd = &mapper->hash.buckets[i];
4396 hlist_for_each_entry(entry, hhd, hlist) {
4397 map = (struct ftrace_func_map *)entry;
4402 free_ftrace_hash(&mapper->hash);
4405 static void release_probe(struct ftrace_func_probe *probe)
4407 struct ftrace_probe_ops *probe_ops;
4409 mutex_lock(&ftrace_lock);
4411 WARN_ON(probe->ref <= 0);
4413 /* Subtract the ref that was used to protect this instance */
4417 probe_ops = probe->probe_ops;
4419 * Sending zero as ip tells probe_ops to free
4420 * the probe->data itself
4422 if (probe_ops->free)
4423 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4424 list_del(&probe->list);
4427 mutex_unlock(&ftrace_lock);
4430 static void acquire_probe_locked(struct ftrace_func_probe *probe)
4433 * Add one ref to keep it from being freed when releasing the
4434 * ftrace_lock mutex.
4440 register_ftrace_function_probe(char *glob, struct trace_array *tr,
4441 struct ftrace_probe_ops *probe_ops,
4444 struct ftrace_func_entry *entry;
4445 struct ftrace_func_probe *probe;
4446 struct ftrace_hash **orig_hash;
4447 struct ftrace_hash *old_hash;
4448 struct ftrace_hash *hash;
4457 /* We do not support '!' for function probes */
4458 if (WARN_ON(glob[0] == '!'))
4462 mutex_lock(&ftrace_lock);
4463 /* Check if the probe_ops is already registered */
4464 list_for_each_entry(probe, &tr->func_probes, list) {
4465 if (probe->probe_ops == probe_ops)
4468 if (&probe->list == &tr->func_probes) {
4469 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4471 mutex_unlock(&ftrace_lock);
4474 probe->probe_ops = probe_ops;
4475 probe->ops.func = function_trace_probe_call;
4477 ftrace_ops_init(&probe->ops);
4478 list_add(&probe->list, &tr->func_probes);
4481 acquire_probe_locked(probe);
4483 mutex_unlock(&ftrace_lock);
4486 * Note, there's a small window here that the func_hash->filter_hash
4487 * may be NULL or empty. Need to be carefule when reading the loop.
4489 mutex_lock(&probe->ops.func_hash->regex_lock);
4491 orig_hash = &probe->ops.func_hash->filter_hash;
4492 old_hash = *orig_hash;
4493 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4500 ret = ftrace_match_records(hash, glob, strlen(glob));
4502 /* Nothing found? */
4509 size = 1 << hash->size_bits;
4510 for (i = 0; i < size; i++) {
4511 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4512 if (ftrace_lookup_ip(old_hash, entry->ip))
4515 * The caller might want to do something special
4516 * for each function we find. We call the callback
4517 * to give the caller an opportunity to do so.
4519 if (probe_ops->init) {
4520 ret = probe_ops->init(probe_ops, tr,
4524 if (probe_ops->free && count)
4525 probe_ops->free(probe_ops, tr,
4535 mutex_lock(&ftrace_lock);
4538 /* Nothing was added? */
4543 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4548 /* One ref for each new function traced */
4549 probe->ref += count;
4551 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4552 ret = ftrace_startup(&probe->ops, 0);
4555 mutex_unlock(&ftrace_lock);
4560 mutex_unlock(&probe->ops.func_hash->regex_lock);
4561 free_ftrace_hash(hash);
4563 release_probe(probe);
4568 if (!probe_ops->free || !count)
4571 /* Failed to do the move, need to call the free functions */
4572 for (i = 0; i < size; i++) {
4573 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4574 if (ftrace_lookup_ip(old_hash, entry->ip))
4576 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4583 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4584 struct ftrace_probe_ops *probe_ops)
4586 struct ftrace_ops_hash old_hash_ops;
4587 struct ftrace_func_entry *entry;
4588 struct ftrace_func_probe *probe;
4589 struct ftrace_glob func_g;
4590 struct ftrace_hash **orig_hash;
4591 struct ftrace_hash *old_hash;
4592 struct ftrace_hash *hash = NULL;
4593 struct hlist_node *tmp;
4594 struct hlist_head hhd;
4595 char str[KSYM_SYMBOL_LEN];
4597 int i, ret = -ENODEV;
4600 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4601 func_g.search = NULL;
4605 func_g.type = filter_parse_regex(glob, strlen(glob),
4606 &func_g.search, ¬);
4607 func_g.len = strlen(func_g.search);
4609 /* we do not support '!' for function probes */
4614 mutex_lock(&ftrace_lock);
4615 /* Check if the probe_ops is already registered */
4616 list_for_each_entry(probe, &tr->func_probes, list) {
4617 if (probe->probe_ops == probe_ops)
4620 if (&probe->list == &tr->func_probes)
4621 goto err_unlock_ftrace;
4624 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4625 goto err_unlock_ftrace;
4627 acquire_probe_locked(probe);
4629 mutex_unlock(&ftrace_lock);
4631 mutex_lock(&probe->ops.func_hash->regex_lock);
4633 orig_hash = &probe->ops.func_hash->filter_hash;
4634 old_hash = *orig_hash;
4636 if (ftrace_hash_empty(old_hash))
4639 old_hash_ops.filter_hash = old_hash;
4640 /* Probes only have filters */
4641 old_hash_ops.notrace_hash = NULL;
4644 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4648 INIT_HLIST_HEAD(&hhd);
4650 size = 1 << hash->size_bits;
4651 for (i = 0; i < size; i++) {
4652 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4654 if (func_g.search) {
4655 kallsyms_lookup(entry->ip, NULL, NULL,
4657 if (!ftrace_match(str, &func_g))
4661 remove_hash_entry(hash, entry);
4662 hlist_add_head(&entry->hlist, &hhd);
4666 /* Nothing found? */
4672 mutex_lock(&ftrace_lock);
4674 WARN_ON(probe->ref < count);
4676 probe->ref -= count;
4678 if (ftrace_hash_empty(hash))
4679 ftrace_shutdown(&probe->ops, 0);
4681 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4684 /* still need to update the function call sites */
4685 if (ftrace_enabled && !ftrace_hash_empty(hash))
4686 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4690 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4691 hlist_del(&entry->hlist);
4692 if (probe_ops->free)
4693 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4696 mutex_unlock(&ftrace_lock);
4699 mutex_unlock(&probe->ops.func_hash->regex_lock);
4700 free_ftrace_hash(hash);
4702 release_probe(probe);
4707 mutex_unlock(&ftrace_lock);
4711 void clear_ftrace_function_probes(struct trace_array *tr)
4713 struct ftrace_func_probe *probe, *n;
4715 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4716 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
4719 static LIST_HEAD(ftrace_commands);
4720 static DEFINE_MUTEX(ftrace_cmd_mutex);
4723 * Currently we only register ftrace commands from __init, so mark this
4726 __init int register_ftrace_command(struct ftrace_func_command *cmd)
4728 struct ftrace_func_command *p;
4731 mutex_lock(&ftrace_cmd_mutex);
4732 list_for_each_entry(p, &ftrace_commands, list) {
4733 if (strcmp(cmd->name, p->name) == 0) {
4738 list_add(&cmd->list, &ftrace_commands);
4740 mutex_unlock(&ftrace_cmd_mutex);
4746 * Currently we only unregister ftrace commands from __init, so mark
4749 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4751 struct ftrace_func_command *p, *n;
4754 mutex_lock(&ftrace_cmd_mutex);
4755 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4756 if (strcmp(cmd->name, p->name) == 0) {
4758 list_del_init(&p->list);
4763 mutex_unlock(&ftrace_cmd_mutex);
4768 static int ftrace_process_regex(struct ftrace_iterator *iter,
4769 char *buff, int len, int enable)
4771 struct ftrace_hash *hash = iter->hash;
4772 struct trace_array *tr = iter->ops->private;
4773 char *func, *command, *next = buff;
4774 struct ftrace_func_command *p;
4777 func = strsep(&next, ":");
4780 ret = ftrace_match_records(hash, func, len);
4790 command = strsep(&next, ":");
4792 mutex_lock(&ftrace_cmd_mutex);
4793 list_for_each_entry(p, &ftrace_commands, list) {
4794 if (strcmp(p->name, command) == 0) {
4795 ret = p->func(tr, hash, func, command, next, enable);
4800 mutex_unlock(&ftrace_cmd_mutex);
4806 ftrace_regex_write(struct file *file, const char __user *ubuf,
4807 size_t cnt, loff_t *ppos, int enable)
4809 struct ftrace_iterator *iter;
4810 struct trace_parser *parser;
4816 if (file->f_mode & FMODE_READ) {
4817 struct seq_file *m = file->private_data;
4820 iter = file->private_data;
4822 if (unlikely(ftrace_disabled))
4825 /* iter->hash is a local copy, so we don't need regex_lock */
4827 parser = &iter->parser;
4828 read = trace_get_user(parser, ubuf, cnt, ppos);
4830 if (read >= 0 && trace_parser_loaded(parser) &&
4831 !trace_parser_cont(parser)) {
4832 ret = ftrace_process_regex(iter, parser->buffer,
4833 parser->idx, enable);
4834 trace_parser_clear(parser);
4845 ftrace_filter_write(struct file *file, const char __user *ubuf,
4846 size_t cnt, loff_t *ppos)
4848 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4852 ftrace_notrace_write(struct file *file, const char __user *ubuf,
4853 size_t cnt, loff_t *ppos)
4855 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4859 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4861 struct ftrace_func_entry *entry;
4863 if (!ftrace_location(ip))
4867 entry = ftrace_lookup_ip(hash, ip);
4870 free_hash_entry(hash, entry);
4874 return add_hash_entry(hash, ip);
4878 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4879 unsigned long ip, int remove, int reset, int enable)
4881 struct ftrace_hash **orig_hash;
4882 struct ftrace_hash *hash;
4885 if (unlikely(ftrace_disabled))
4888 mutex_lock(&ops->func_hash->regex_lock);
4891 orig_hash = &ops->func_hash->filter_hash;
4893 orig_hash = &ops->func_hash->notrace_hash;
4896 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4898 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4902 goto out_regex_unlock;
4905 if (buf && !ftrace_match_records(hash, buf, len)) {
4907 goto out_regex_unlock;
4910 ret = ftrace_match_addr(hash, ip, remove);
4912 goto out_regex_unlock;
4915 mutex_lock(&ftrace_lock);
4916 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
4917 mutex_unlock(&ftrace_lock);
4920 mutex_unlock(&ops->func_hash->regex_lock);
4922 free_ftrace_hash(hash);
4927 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
4928 int reset, int enable)
4930 return ftrace_set_hash(ops, NULL, 0, ip, remove, reset, enable);
4933 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
4935 struct ftrace_direct_func {
4936 struct list_head next;
4941 static LIST_HEAD(ftrace_direct_funcs);
4944 * ftrace_find_direct_func - test an address if it is a registered direct caller
4945 * @addr: The address of a registered direct caller
4947 * This searches to see if a ftrace direct caller has been registered
4948 * at a specific address, and if so, it returns a descriptor for it.
4950 * This can be used by architecture code to see if an address is
4951 * a direct caller (trampoline) attached to a fentry/mcount location.
4952 * This is useful for the function_graph tracer, as it may need to
4953 * do adjustments if it traced a location that also has a direct
4954 * trampoline attached to it.
4956 struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
4958 struct ftrace_direct_func *entry;
4961 /* May be called by fgraph trampoline (protected by rcu tasks) */
4962 list_for_each_entry_rcu(entry, &ftrace_direct_funcs, next) {
4963 if (entry->addr == addr) {
4975 * register_ftrace_direct - Call a custom trampoline directly
4976 * @ip: The address of the nop at the beginning of a function
4977 * @addr: The address of the trampoline to call at @ip
4979 * This is used to connect a direct call from the nop location (@ip)
4980 * at the start of ftrace traced functions. The location that it calls
4981 * (@addr) must be able to handle a direct call, and save the parameters
4982 * of the function being traced, and restore them (or inject new ones
4983 * if needed), before returning.
4987 * -EBUSY - Another direct function is already attached (there can be only one)
4988 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
4989 * -ENOMEM - There was an allocation failure.
4991 int register_ftrace_direct(unsigned long ip, unsigned long addr)
4993 struct ftrace_direct_func *direct;
4994 struct ftrace_func_entry *entry;
4995 struct ftrace_hash *free_hash = NULL;
4996 struct dyn_ftrace *rec;
4999 mutex_lock(&direct_mutex);
5001 /* See if there's a direct function at @ip already */
5002 if (ftrace_find_rec_direct(ip))
5006 rec = lookup_rec(ip, ip);
5011 * Check if the rec says it has a direct call but we didn't
5014 if (WARN_ON(rec->flags & FTRACE_FL_DIRECT))
5017 /* Make sure the ip points to the exact record */
5018 if (ip != rec->ip) {
5020 /* Need to check this ip for a direct. */
5021 if (ftrace_find_rec_direct(ip))
5026 if (ftrace_hash_empty(direct_functions) ||
5027 direct_functions->count > 2 * (1 << direct_functions->size_bits)) {
5028 struct ftrace_hash *new_hash;
5029 int size = ftrace_hash_empty(direct_functions) ? 0 :
5030 direct_functions->count + 1;
5035 new_hash = dup_hash(direct_functions, size);
5039 free_hash = direct_functions;
5040 direct_functions = new_hash;
5043 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
5047 direct = ftrace_find_direct_func(addr);
5049 direct = kmalloc(sizeof(*direct), GFP_KERNEL);
5054 direct->addr = addr;
5056 list_add_rcu(&direct->next, &ftrace_direct_funcs);
5057 ftrace_direct_func_count++;
5061 entry->direct = addr;
5062 __add_hash_entry(direct_functions, entry);
5064 ret = ftrace_set_filter_ip(&direct_ops, ip, 0, 0);
5066 remove_hash_entry(direct_functions, entry);
5068 if (!ret && !(direct_ops.flags & FTRACE_OPS_FL_ENABLED)) {
5069 ret = register_ftrace_function(&direct_ops);
5071 ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5076 if (!direct->count) {
5077 list_del_rcu(&direct->next);
5078 synchronize_rcu_tasks();
5081 free_ftrace_hash(free_hash);
5083 ftrace_direct_func_count--;
5089 mutex_unlock(&direct_mutex);
5092 synchronize_rcu_tasks();
5093 free_ftrace_hash(free_hash);
5098 EXPORT_SYMBOL_GPL(register_ftrace_direct);
5100 static struct ftrace_func_entry *find_direct_entry(unsigned long *ip,
5101 struct dyn_ftrace **recp)
5103 struct ftrace_func_entry *entry;
5104 struct dyn_ftrace *rec;
5106 rec = lookup_rec(*ip, *ip);
5110 entry = __ftrace_lookup_ip(direct_functions, rec->ip);
5112 WARN_ON(rec->flags & FTRACE_FL_DIRECT);
5116 WARN_ON(!(rec->flags & FTRACE_FL_DIRECT));
5118 /* Passed in ip just needs to be on the call site */
5127 int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
5129 struct ftrace_direct_func *direct;
5130 struct ftrace_func_entry *entry;
5133 mutex_lock(&direct_mutex);
5135 entry = find_direct_entry(&ip, NULL);
5139 if (direct_functions->count == 1)
5140 unregister_ftrace_function(&direct_ops);
5142 ret = ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5146 remove_hash_entry(direct_functions, entry);
5148 direct = ftrace_find_direct_func(addr);
5149 if (!WARN_ON(!direct)) {
5150 /* This is the good path (see the ! before WARN) */
5152 WARN_ON(direct->count < 0);
5153 if (!direct->count) {
5154 list_del_rcu(&direct->next);
5155 synchronize_rcu_tasks();
5158 ftrace_direct_func_count--;
5162 mutex_unlock(&direct_mutex);
5166 EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
5168 static struct ftrace_ops stub_ops = {
5169 .func = ftrace_stub,
5173 * ftrace_modify_direct_caller - modify ftrace nop directly
5174 * @entry: The ftrace hash entry of the direct helper for @rec
5175 * @rec: The record representing the function site to patch
5176 * @old_addr: The location that the site at @rec->ip currently calls
5177 * @new_addr: The location that the site at @rec->ip should call
5179 * An architecture may overwrite this function to optimize the
5180 * changing of the direct callback on an ftrace nop location.
5181 * This is called with the ftrace_lock mutex held, and no other
5182 * ftrace callbacks are on the associated record (@rec). Thus,
5183 * it is safe to modify the ftrace record, where it should be
5184 * currently calling @old_addr directly, to call @new_addr.
5186 * Safety checks should be made to make sure that the code at
5187 * @rec->ip is currently calling @old_addr. And this must
5188 * also update entry->direct to @new_addr.
5190 int __weak ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
5191 struct dyn_ftrace *rec,
5192 unsigned long old_addr,
5193 unsigned long new_addr)
5195 unsigned long ip = rec->ip;
5199 * The ftrace_lock was used to determine if the record
5200 * had more than one registered user to it. If it did,
5201 * we needed to prevent that from changing to do the quick
5202 * switch. But if it did not (only a direct caller was attached)
5203 * then this function is called. But this function can deal
5204 * with attached callers to the rec that we care about, and
5205 * since this function uses standard ftrace calls that take
5206 * the ftrace_lock mutex, we need to release it.
5208 mutex_unlock(&ftrace_lock);
5211 * By setting a stub function at the same address, we force
5212 * the code to call the iterator and the direct_ops helper.
5213 * This means that @ip does not call the direct call, and
5214 * we can simply modify it.
5216 ret = ftrace_set_filter_ip(&stub_ops, ip, 0, 0);
5220 ret = register_ftrace_function(&stub_ops);
5222 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5226 entry->direct = new_addr;
5229 * By removing the stub, we put back the direct call, calling
5232 unregister_ftrace_function(&stub_ops);
5233 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5236 mutex_lock(&ftrace_lock);
5242 * modify_ftrace_direct - Modify an existing direct call to call something else
5243 * @ip: The instruction pointer to modify
5244 * @old_addr: The address that the current @ip calls directly
5245 * @new_addr: The address that the @ip should call
5247 * This modifies a ftrace direct caller at an instruction pointer without
5248 * having to disable it first. The direct call will switch over to the
5249 * @new_addr without missing anything.
5251 * Returns: zero on success. Non zero on error, which includes:
5252 * -ENODEV : the @ip given has no direct caller attached
5253 * -EINVAL : the @old_addr does not match the current direct caller
5255 int modify_ftrace_direct(unsigned long ip,
5256 unsigned long old_addr, unsigned long new_addr)
5258 struct ftrace_func_entry *entry;
5259 struct dyn_ftrace *rec;
5262 mutex_lock(&direct_mutex);
5264 mutex_lock(&ftrace_lock);
5265 entry = find_direct_entry(&ip, &rec);
5270 if (entry->direct != old_addr)
5274 * If there's no other ftrace callback on the rec->ip location,
5275 * then it can be changed directly by the architecture.
5276 * If there is another caller, then we just need to change the
5277 * direct caller helper to point to @new_addr.
5279 if (ftrace_rec_count(rec) == 1) {
5280 ret = ftrace_modify_direct_caller(entry, rec, old_addr, new_addr);
5282 entry->direct = new_addr;
5287 mutex_unlock(&ftrace_lock);
5288 mutex_unlock(&direct_mutex);
5291 EXPORT_SYMBOL_GPL(modify_ftrace_direct);
5292 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
5295 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
5296 * @ops - the ops to set the filter with
5297 * @ip - the address to add to or remove from the filter.
5298 * @remove - non zero to remove the ip from the filter
5299 * @reset - non zero to reset all filters before applying this filter.
5301 * Filters denote which functions should be enabled when tracing is enabled
5302 * If @ip is NULL, it failes to update filter.
5304 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
5305 int remove, int reset)
5307 ftrace_ops_init(ops);
5308 return ftrace_set_addr(ops, ip, remove, reset, 1);
5310 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
5313 * ftrace_ops_set_global_filter - setup ops to use global filters
5314 * @ops - the ops which will use the global filters
5316 * ftrace users who need global function trace filtering should call this.
5317 * It can set the global filter only if ops were not initialized before.
5319 void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
5321 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
5324 ftrace_ops_init(ops);
5325 ops->func_hash = &global_ops.local_hash;
5327 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
5330 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
5331 int reset, int enable)
5333 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
5337 * ftrace_set_filter - set a function to filter on in ftrace
5338 * @ops - the ops to set the filter with
5339 * @buf - the string that holds the function filter text.
5340 * @len - the length of the string.
5341 * @reset - non zero to reset all filters before applying this filter.
5343 * Filters denote which functions should be enabled when tracing is enabled.
5344 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5346 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
5349 ftrace_ops_init(ops);
5350 return ftrace_set_regex(ops, buf, len, reset, 1);
5352 EXPORT_SYMBOL_GPL(ftrace_set_filter);
5355 * ftrace_set_notrace - set a function to not trace in ftrace
5356 * @ops - the ops to set the notrace filter with
5357 * @buf - the string that holds the function notrace text.
5358 * @len - the length of the string.
5359 * @reset - non zero to reset all filters before applying this filter.
5361 * Notrace Filters denote which functions should not be enabled when tracing
5362 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5365 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
5368 ftrace_ops_init(ops);
5369 return ftrace_set_regex(ops, buf, len, reset, 0);
5371 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
5373 * ftrace_set_global_filter - set a function to filter on with global tracers
5374 * @buf - the string that holds the function filter text.
5375 * @len - the length of the string.
5376 * @reset - non zero to reset all filters before applying this filter.
5378 * Filters denote which functions should be enabled when tracing is enabled.
5379 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5381 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
5383 ftrace_set_regex(&global_ops, buf, len, reset, 1);
5385 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
5388 * ftrace_set_global_notrace - set a function to not trace with global tracers
5389 * @buf - the string that holds the function notrace text.
5390 * @len - the length of the string.
5391 * @reset - non zero to reset all filters before applying this filter.
5393 * Notrace Filters denote which functions should not be enabled when tracing
5394 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5397 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
5399 ftrace_set_regex(&global_ops, buf, len, reset, 0);
5401 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
5404 * command line interface to allow users to set filters on boot up.
5406 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
5407 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5408 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
5410 /* Used by function selftest to not test if filter is set */
5411 bool ftrace_filter_param __initdata;
5413 static int __init set_ftrace_notrace(char *str)
5415 ftrace_filter_param = true;
5416 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
5419 __setup("ftrace_notrace=", set_ftrace_notrace);
5421 static int __init set_ftrace_filter(char *str)
5423 ftrace_filter_param = true;
5424 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
5427 __setup("ftrace_filter=", set_ftrace_filter);
5429 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5430 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
5431 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5432 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
5434 static int __init set_graph_function(char *str)
5436 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
5439 __setup("ftrace_graph_filter=", set_graph_function);
5441 static int __init set_graph_notrace_function(char *str)
5443 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
5446 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
5448 static int __init set_graph_max_depth_function(char *str)
5452 fgraph_max_depth = simple_strtoul(str, NULL, 0);
5455 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
5457 static void __init set_ftrace_early_graph(char *buf, int enable)
5461 struct ftrace_hash *hash;
5463 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5464 if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
5468 func = strsep(&buf, ",");
5469 /* we allow only one expression at a time */
5470 ret = ftrace_graph_set_hash(hash, func);
5472 printk(KERN_DEBUG "ftrace: function %s not "
5473 "traceable\n", func);
5477 ftrace_graph_hash = hash;
5479 ftrace_graph_notrace_hash = hash;
5481 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5484 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
5488 ftrace_ops_init(ops);
5491 func = strsep(&buf, ",");
5492 ftrace_set_regex(ops, func, strlen(func), 0, enable);
5496 static void __init set_ftrace_early_filters(void)
5498 if (ftrace_filter_buf[0])
5499 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
5500 if (ftrace_notrace_buf[0])
5501 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
5502 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5503 if (ftrace_graph_buf[0])
5504 set_ftrace_early_graph(ftrace_graph_buf, 1);
5505 if (ftrace_graph_notrace_buf[0])
5506 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
5507 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5510 int ftrace_regex_release(struct inode *inode, struct file *file)
5512 struct seq_file *m = (struct seq_file *)file->private_data;
5513 struct ftrace_iterator *iter;
5514 struct ftrace_hash **orig_hash;
5515 struct trace_parser *parser;
5519 if (file->f_mode & FMODE_READ) {
5521 seq_release(inode, file);
5523 iter = file->private_data;
5525 parser = &iter->parser;
5526 if (trace_parser_loaded(parser)) {
5527 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
5530 trace_parser_put(parser);
5532 mutex_lock(&iter->ops->func_hash->regex_lock);
5534 if (file->f_mode & FMODE_WRITE) {
5535 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5538 orig_hash = &iter->ops->func_hash->filter_hash;
5539 if (iter->tr && !list_empty(&iter->tr->mod_trace))
5540 iter->hash->flags |= FTRACE_HASH_FL_MOD;
5542 orig_hash = &iter->ops->func_hash->notrace_hash;
5544 mutex_lock(&ftrace_lock);
5545 ret = ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5546 iter->hash, filter_hash);
5547 mutex_unlock(&ftrace_lock);
5549 /* For read only, the hash is the ops hash */
5553 mutex_unlock(&iter->ops->func_hash->regex_lock);
5554 free_ftrace_hash(iter->hash);
5556 trace_array_put(iter->tr);
5562 static const struct file_operations ftrace_avail_fops = {
5563 .open = ftrace_avail_open,
5565 .llseek = seq_lseek,
5566 .release = seq_release_private,
5569 static const struct file_operations ftrace_enabled_fops = {
5570 .open = ftrace_enabled_open,
5572 .llseek = seq_lseek,
5573 .release = seq_release_private,
5576 static const struct file_operations ftrace_filter_fops = {
5577 .open = ftrace_filter_open,
5579 .write = ftrace_filter_write,
5580 .llseek = tracing_lseek,
5581 .release = ftrace_regex_release,
5584 static const struct file_operations ftrace_notrace_fops = {
5585 .open = ftrace_notrace_open,
5587 .write = ftrace_notrace_write,
5588 .llseek = tracing_lseek,
5589 .release = ftrace_regex_release,
5592 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5594 static DEFINE_MUTEX(graph_lock);
5596 struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
5597 struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
5599 enum graph_filter_type {
5600 GRAPH_FILTER_NOTRACE = 0,
5601 GRAPH_FILTER_FUNCTION,
5604 #define FTRACE_GRAPH_EMPTY ((void *)1)
5606 struct ftrace_graph_data {
5607 struct ftrace_hash *hash;
5608 struct ftrace_func_entry *entry;
5609 int idx; /* for hash table iteration */
5610 enum graph_filter_type type;
5611 struct ftrace_hash *new_hash;
5612 const struct seq_operations *seq_ops;
5613 struct trace_parser parser;
5617 __g_next(struct seq_file *m, loff_t *pos)
5619 struct ftrace_graph_data *fgd = m->private;
5620 struct ftrace_func_entry *entry = fgd->entry;
5621 struct hlist_head *head;
5622 int i, idx = fgd->idx;
5624 if (*pos >= fgd->hash->count)
5628 hlist_for_each_entry_continue(entry, hlist) {
5636 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
5637 head = &fgd->hash->buckets[i];
5638 hlist_for_each_entry(entry, head, hlist) {
5648 g_next(struct seq_file *m, void *v, loff_t *pos)
5651 return __g_next(m, pos);
5654 static void *g_start(struct seq_file *m, loff_t *pos)
5656 struct ftrace_graph_data *fgd = m->private;
5658 mutex_lock(&graph_lock);
5660 if (fgd->type == GRAPH_FILTER_FUNCTION)
5661 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5662 lockdep_is_held(&graph_lock));
5664 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5665 lockdep_is_held(&graph_lock));
5667 /* Nothing, tell g_show to print all functions are enabled */
5668 if (ftrace_hash_empty(fgd->hash) && !*pos)
5669 return FTRACE_GRAPH_EMPTY;
5673 return __g_next(m, pos);
5676 static void g_stop(struct seq_file *m, void *p)
5678 mutex_unlock(&graph_lock);
5681 static int g_show(struct seq_file *m, void *v)
5683 struct ftrace_func_entry *entry = v;
5688 if (entry == FTRACE_GRAPH_EMPTY) {
5689 struct ftrace_graph_data *fgd = m->private;
5691 if (fgd->type == GRAPH_FILTER_FUNCTION)
5692 seq_puts(m, "#### all functions enabled ####\n");
5694 seq_puts(m, "#### no functions disabled ####\n");
5698 seq_printf(m, "%ps\n", (void *)entry->ip);
5703 static const struct seq_operations ftrace_graph_seq_ops = {
5711 __ftrace_graph_open(struct inode *inode, struct file *file,
5712 struct ftrace_graph_data *fgd)
5715 struct ftrace_hash *new_hash = NULL;
5717 ret = security_locked_down(LOCKDOWN_TRACEFS);
5721 if (file->f_mode & FMODE_WRITE) {
5722 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
5724 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
5727 if (file->f_flags & O_TRUNC)
5728 new_hash = alloc_ftrace_hash(size_bits);
5730 new_hash = alloc_and_copy_ftrace_hash(size_bits,
5738 if (file->f_mode & FMODE_READ) {
5739 ret = seq_open(file, &ftrace_graph_seq_ops);
5741 struct seq_file *m = file->private_data;
5745 free_ftrace_hash(new_hash);
5749 file->private_data = fgd;
5752 if (ret < 0 && file->f_mode & FMODE_WRITE)
5753 trace_parser_put(&fgd->parser);
5755 fgd->new_hash = new_hash;
5758 * All uses of fgd->hash must be taken with the graph_lock
5759 * held. The graph_lock is going to be released, so force
5760 * fgd->hash to be reinitialized when it is taken again.
5768 ftrace_graph_open(struct inode *inode, struct file *file)
5770 struct ftrace_graph_data *fgd;
5773 if (unlikely(ftrace_disabled))
5776 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5780 mutex_lock(&graph_lock);
5782 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5783 lockdep_is_held(&graph_lock));
5784 fgd->type = GRAPH_FILTER_FUNCTION;
5785 fgd->seq_ops = &ftrace_graph_seq_ops;
5787 ret = __ftrace_graph_open(inode, file, fgd);
5791 mutex_unlock(&graph_lock);
5796 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
5798 struct ftrace_graph_data *fgd;
5801 if (unlikely(ftrace_disabled))
5804 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5808 mutex_lock(&graph_lock);
5810 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5811 lockdep_is_held(&graph_lock));
5812 fgd->type = GRAPH_FILTER_NOTRACE;
5813 fgd->seq_ops = &ftrace_graph_seq_ops;
5815 ret = __ftrace_graph_open(inode, file, fgd);
5819 mutex_unlock(&graph_lock);
5824 ftrace_graph_release(struct inode *inode, struct file *file)
5826 struct ftrace_graph_data *fgd;
5827 struct ftrace_hash *old_hash, *new_hash;
5828 struct trace_parser *parser;
5831 if (file->f_mode & FMODE_READ) {
5832 struct seq_file *m = file->private_data;
5835 seq_release(inode, file);
5837 fgd = file->private_data;
5841 if (file->f_mode & FMODE_WRITE) {
5843 parser = &fgd->parser;
5845 if (trace_parser_loaded((parser))) {
5846 ret = ftrace_graph_set_hash(fgd->new_hash,
5850 trace_parser_put(parser);
5852 new_hash = __ftrace_hash_move(fgd->new_hash);
5858 mutex_lock(&graph_lock);
5860 if (fgd->type == GRAPH_FILTER_FUNCTION) {
5861 old_hash = rcu_dereference_protected(ftrace_graph_hash,
5862 lockdep_is_held(&graph_lock));
5863 rcu_assign_pointer(ftrace_graph_hash, new_hash);
5865 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5866 lockdep_is_held(&graph_lock));
5867 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
5870 mutex_unlock(&graph_lock);
5873 * We need to do a hard force of sched synchronization.
5874 * This is because we use preempt_disable() to do RCU, but
5875 * the function tracers can be called where RCU is not watching
5876 * (like before user_exit()). We can not rely on the RCU
5877 * infrastructure to do the synchronization, thus we must do it
5880 synchronize_rcu_tasks_rude();
5882 free_ftrace_hash(old_hash);
5886 free_ftrace_hash(fgd->new_hash);
5893 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
5895 struct ftrace_glob func_g;
5896 struct dyn_ftrace *rec;
5897 struct ftrace_page *pg;
5898 struct ftrace_func_entry *entry;
5903 func_g.type = filter_parse_regex(buffer, strlen(buffer),
5904 &func_g.search, ¬);
5906 func_g.len = strlen(func_g.search);
5908 mutex_lock(&ftrace_lock);
5910 if (unlikely(ftrace_disabled)) {
5911 mutex_unlock(&ftrace_lock);
5915 do_for_each_ftrace_rec(pg, rec) {
5917 if (rec->flags & FTRACE_FL_DISABLED)
5920 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
5921 entry = ftrace_lookup_ip(hash, rec->ip);
5928 if (add_hash_entry(hash, rec->ip) < 0)
5932 free_hash_entry(hash, entry);
5937 } while_for_each_ftrace_rec();
5939 mutex_unlock(&ftrace_lock);
5948 ftrace_graph_write(struct file *file, const char __user *ubuf,
5949 size_t cnt, loff_t *ppos)
5951 ssize_t read, ret = 0;
5952 struct ftrace_graph_data *fgd = file->private_data;
5953 struct trace_parser *parser;
5958 /* Read mode uses seq functions */
5959 if (file->f_mode & FMODE_READ) {
5960 struct seq_file *m = file->private_data;
5964 parser = &fgd->parser;
5966 read = trace_get_user(parser, ubuf, cnt, ppos);
5968 if (read >= 0 && trace_parser_loaded(parser) &&
5969 !trace_parser_cont(parser)) {
5971 ret = ftrace_graph_set_hash(fgd->new_hash,
5973 trace_parser_clear(parser);
5982 static const struct file_operations ftrace_graph_fops = {
5983 .open = ftrace_graph_open,
5985 .write = ftrace_graph_write,
5986 .llseek = tracing_lseek,
5987 .release = ftrace_graph_release,
5990 static const struct file_operations ftrace_graph_notrace_fops = {
5991 .open = ftrace_graph_notrace_open,
5993 .write = ftrace_graph_write,
5994 .llseek = tracing_lseek,
5995 .release = ftrace_graph_release,
5997 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5999 void ftrace_create_filter_files(struct ftrace_ops *ops,
6000 struct dentry *parent)
6003 trace_create_file("set_ftrace_filter", 0644, parent,
6004 ops, &ftrace_filter_fops);
6006 trace_create_file("set_ftrace_notrace", 0644, parent,
6007 ops, &ftrace_notrace_fops);
6011 * The name "destroy_filter_files" is really a misnomer. Although
6012 * in the future, it may actually delete the files, but this is
6013 * really intended to make sure the ops passed in are disabled
6014 * and that when this function returns, the caller is free to
6017 * The "destroy" name is only to match the "create" name that this
6018 * should be paired with.
6020 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
6022 mutex_lock(&ftrace_lock);
6023 if (ops->flags & FTRACE_OPS_FL_ENABLED)
6024 ftrace_shutdown(ops, 0);
6025 ops->flags |= FTRACE_OPS_FL_DELETED;
6026 ftrace_free_filter(ops);
6027 mutex_unlock(&ftrace_lock);
6030 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
6033 trace_create_file("available_filter_functions", 0444,
6034 d_tracer, NULL, &ftrace_avail_fops);
6036 trace_create_file("enabled_functions", 0444,
6037 d_tracer, NULL, &ftrace_enabled_fops);
6039 ftrace_create_filter_files(&global_ops, d_tracer);
6041 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
6042 trace_create_file("set_graph_function", 0644, d_tracer,
6044 &ftrace_graph_fops);
6045 trace_create_file("set_graph_notrace", 0644, d_tracer,
6047 &ftrace_graph_notrace_fops);
6048 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6053 static int ftrace_cmp_ips(const void *a, const void *b)
6055 const unsigned long *ipa = a;
6056 const unsigned long *ipb = b;
6065 static int ftrace_process_locs(struct module *mod,
6066 unsigned long *start,
6069 struct ftrace_page *start_pg;
6070 struct ftrace_page *pg;
6071 struct dyn_ftrace *rec;
6072 unsigned long count;
6075 unsigned long flags = 0; /* Shut up gcc */
6078 count = end - start;
6083 sort(start, count, sizeof(*start),
6084 ftrace_cmp_ips, NULL);
6086 start_pg = ftrace_allocate_pages(count);
6090 mutex_lock(&ftrace_lock);
6093 * Core and each module needs their own pages, as
6094 * modules will free them when they are removed.
6095 * Force a new page to be allocated for modules.
6098 WARN_ON(ftrace_pages || ftrace_pages_start);
6099 /* First initialization */
6100 ftrace_pages = ftrace_pages_start = start_pg;
6105 if (WARN_ON(ftrace_pages->next)) {
6106 /* Hmm, we have free pages? */
6107 while (ftrace_pages->next)
6108 ftrace_pages = ftrace_pages->next;
6111 ftrace_pages->next = start_pg;
6117 addr = ftrace_call_adjust(*p++);
6119 * Some architecture linkers will pad between
6120 * the different mcount_loc sections of different
6121 * object files to satisfy alignments.
6122 * Skip any NULL pointers.
6127 if (pg->index == pg->size) {
6128 /* We should have allocated enough */
6129 if (WARN_ON(!pg->next))
6134 rec = &pg->records[pg->index++];
6138 /* We should have used all pages */
6141 /* Assign the last page to ftrace_pages */
6145 * We only need to disable interrupts on start up
6146 * because we are modifying code that an interrupt
6147 * may execute, and the modification is not atomic.
6148 * But for modules, nothing runs the code we modify
6149 * until we are finished with it, and there's no
6150 * reason to cause large interrupt latencies while we do it.
6153 local_irq_save(flags);
6154 ftrace_update_code(mod, start_pg);
6156 local_irq_restore(flags);
6159 mutex_unlock(&ftrace_lock);
6164 struct ftrace_mod_func {
6165 struct list_head list;
6171 struct ftrace_mod_map {
6172 struct rcu_head rcu;
6173 struct list_head list;
6175 unsigned long start_addr;
6176 unsigned long end_addr;
6177 struct list_head funcs;
6178 unsigned int num_funcs;
6181 #ifdef CONFIG_MODULES
6183 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
6185 static LIST_HEAD(ftrace_mod_maps);
6187 static int referenced_filters(struct dyn_ftrace *rec)
6189 struct ftrace_ops *ops;
6192 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
6193 if (ops_references_rec(ops, rec))
6201 clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
6203 struct ftrace_func_entry *entry;
6204 struct dyn_ftrace *rec;
6207 if (ftrace_hash_empty(hash))
6210 for (i = 0; i < pg->index; i++) {
6211 rec = &pg->records[i];
6212 entry = __ftrace_lookup_ip(hash, rec->ip);
6214 * Do not allow this rec to match again.
6215 * Yeah, it may waste some memory, but will be removed
6216 * if/when the hash is modified again.
6223 /* Clear any records from hashs */
6224 static void clear_mod_from_hashes(struct ftrace_page *pg)
6226 struct trace_array *tr;
6228 mutex_lock(&trace_types_lock);
6229 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6230 if (!tr->ops || !tr->ops->func_hash)
6232 mutex_lock(&tr->ops->func_hash->regex_lock);
6233 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
6234 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
6235 mutex_unlock(&tr->ops->func_hash->regex_lock);
6237 mutex_unlock(&trace_types_lock);
6240 static void ftrace_free_mod_map(struct rcu_head *rcu)
6242 struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
6243 struct ftrace_mod_func *mod_func;
6244 struct ftrace_mod_func *n;
6246 /* All the contents of mod_map are now not visible to readers */
6247 list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
6248 kfree(mod_func->name);
6249 list_del(&mod_func->list);
6256 void ftrace_release_mod(struct module *mod)
6258 struct ftrace_mod_map *mod_map;
6259 struct ftrace_mod_map *n;
6260 struct dyn_ftrace *rec;
6261 struct ftrace_page **last_pg;
6262 struct ftrace_page *tmp_page = NULL;
6263 struct ftrace_page *pg;
6266 mutex_lock(&ftrace_lock);
6268 if (ftrace_disabled)
6271 list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
6272 if (mod_map->mod == mod) {
6273 list_del_rcu(&mod_map->list);
6274 call_rcu(&mod_map->rcu, ftrace_free_mod_map);
6280 * Each module has its own ftrace_pages, remove
6281 * them from the list.
6283 last_pg = &ftrace_pages_start;
6284 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
6285 rec = &pg->records[0];
6286 if (within_module_core(rec->ip, mod) ||
6287 within_module_init(rec->ip, mod)) {
6289 * As core pages are first, the first
6290 * page should never be a module page.
6292 if (WARN_ON(pg == ftrace_pages_start))
6295 /* Check if we are deleting the last page */
6296 if (pg == ftrace_pages)
6297 ftrace_pages = next_to_ftrace_page(last_pg);
6299 ftrace_update_tot_cnt -= pg->index;
6300 *last_pg = pg->next;
6302 pg->next = tmp_page;
6305 last_pg = &pg->next;
6308 mutex_unlock(&ftrace_lock);
6310 for (pg = tmp_page; pg; pg = tmp_page) {
6312 /* Needs to be called outside of ftrace_lock */
6313 clear_mod_from_hashes(pg);
6315 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
6316 free_pages((unsigned long)pg->records, order);
6317 tmp_page = pg->next;
6319 ftrace_number_of_pages -= 1 << order;
6320 ftrace_number_of_groups--;
6324 void ftrace_module_enable(struct module *mod)
6326 struct dyn_ftrace *rec;
6327 struct ftrace_page *pg;
6329 mutex_lock(&ftrace_lock);
6331 if (ftrace_disabled)
6335 * If the tracing is enabled, go ahead and enable the record.
6337 * The reason not to enable the record immediately is the
6338 * inherent check of ftrace_make_nop/ftrace_make_call for
6339 * correct previous instructions. Making first the NOP
6340 * conversion puts the module to the correct state, thus
6341 * passing the ftrace_make_call check.
6343 * We also delay this to after the module code already set the
6344 * text to read-only, as we now need to set it back to read-write
6345 * so that we can modify the text.
6347 if (ftrace_start_up)
6348 ftrace_arch_code_modify_prepare();
6350 do_for_each_ftrace_rec(pg, rec) {
6353 * do_for_each_ftrace_rec() is a double loop.
6354 * module text shares the pg. If a record is
6355 * not part of this module, then skip this pg,
6356 * which the "break" will do.
6358 if (!within_module_core(rec->ip, mod) &&
6359 !within_module_init(rec->ip, mod))
6365 * When adding a module, we need to check if tracers are
6366 * currently enabled and if they are, and can trace this record,
6367 * we need to enable the module functions as well as update the
6368 * reference counts for those function records.
6370 if (ftrace_start_up)
6371 cnt += referenced_filters(rec);
6373 /* This clears FTRACE_FL_DISABLED */
6376 if (ftrace_start_up && cnt) {
6377 int failed = __ftrace_replace_code(rec, 1);
6379 ftrace_bug(failed, rec);
6384 } while_for_each_ftrace_rec();
6387 if (ftrace_start_up)
6388 ftrace_arch_code_modify_post_process();
6391 mutex_unlock(&ftrace_lock);
6393 process_cached_mods(mod->name);
6396 void ftrace_module_init(struct module *mod)
6398 if (ftrace_disabled || !mod->num_ftrace_callsites)
6401 ftrace_process_locs(mod, mod->ftrace_callsites,
6402 mod->ftrace_callsites + mod->num_ftrace_callsites);
6405 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6406 struct dyn_ftrace *rec)
6408 struct ftrace_mod_func *mod_func;
6409 unsigned long symsize;
6410 unsigned long offset;
6411 char str[KSYM_SYMBOL_LEN];
6415 ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
6419 mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
6423 mod_func->name = kstrdup(str, GFP_KERNEL);
6424 if (!mod_func->name) {
6429 mod_func->ip = rec->ip - offset;
6430 mod_func->size = symsize;
6432 mod_map->num_funcs++;
6434 list_add_rcu(&mod_func->list, &mod_map->funcs);
6437 static struct ftrace_mod_map *
6438 allocate_ftrace_mod_map(struct module *mod,
6439 unsigned long start, unsigned long end)
6441 struct ftrace_mod_map *mod_map;
6443 mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
6448 mod_map->start_addr = start;
6449 mod_map->end_addr = end;
6450 mod_map->num_funcs = 0;
6452 INIT_LIST_HEAD_RCU(&mod_map->funcs);
6454 list_add_rcu(&mod_map->list, &ftrace_mod_maps);
6460 ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
6461 unsigned long addr, unsigned long *size,
6462 unsigned long *off, char *sym)
6464 struct ftrace_mod_func *found_func = NULL;
6465 struct ftrace_mod_func *mod_func;
6467 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6468 if (addr >= mod_func->ip &&
6469 addr < mod_func->ip + mod_func->size) {
6470 found_func = mod_func;
6477 *size = found_func->size;
6479 *off = addr - found_func->ip;
6481 strlcpy(sym, found_func->name, KSYM_NAME_LEN);
6483 return found_func->name;
6490 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
6491 unsigned long *off, char **modname, char *sym)
6493 struct ftrace_mod_map *mod_map;
6494 const char *ret = NULL;
6496 /* mod_map is freed via call_rcu() */
6498 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6499 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
6502 *modname = mod_map->mod->name;
6511 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
6512 char *type, char *name,
6513 char *module_name, int *exported)
6515 struct ftrace_mod_map *mod_map;
6516 struct ftrace_mod_func *mod_func;
6519 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6521 if (symnum >= mod_map->num_funcs) {
6522 symnum -= mod_map->num_funcs;
6526 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6532 *value = mod_func->ip;
6534 strlcpy(name, mod_func->name, KSYM_NAME_LEN);
6535 strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
6548 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6549 struct dyn_ftrace *rec) { }
6550 static inline struct ftrace_mod_map *
6551 allocate_ftrace_mod_map(struct module *mod,
6552 unsigned long start, unsigned long end)
6556 #endif /* CONFIG_MODULES */
6558 struct ftrace_init_func {
6559 struct list_head list;
6563 /* Clear any init ips from hashes */
6565 clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
6567 struct ftrace_func_entry *entry;
6569 entry = ftrace_lookup_ip(hash, func->ip);
6571 * Do not allow this rec to match again.
6572 * Yeah, it may waste some memory, but will be removed
6573 * if/when the hash is modified again.
6580 clear_func_from_hashes(struct ftrace_init_func *func)
6582 struct trace_array *tr;
6584 mutex_lock(&trace_types_lock);
6585 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6586 if (!tr->ops || !tr->ops->func_hash)
6588 mutex_lock(&tr->ops->func_hash->regex_lock);
6589 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
6590 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
6591 mutex_unlock(&tr->ops->func_hash->regex_lock);
6593 mutex_unlock(&trace_types_lock);
6596 static void add_to_clear_hash_list(struct list_head *clear_list,
6597 struct dyn_ftrace *rec)
6599 struct ftrace_init_func *func;
6601 func = kmalloc(sizeof(*func), GFP_KERNEL);
6603 MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
6608 list_add(&func->list, clear_list);
6611 void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
6613 unsigned long start = (unsigned long)(start_ptr);
6614 unsigned long end = (unsigned long)(end_ptr);
6615 struct ftrace_page **last_pg = &ftrace_pages_start;
6616 struct ftrace_page *pg;
6617 struct dyn_ftrace *rec;
6618 struct dyn_ftrace key;
6619 struct ftrace_mod_map *mod_map = NULL;
6620 struct ftrace_init_func *func, *func_next;
6621 struct list_head clear_hash;
6624 INIT_LIST_HEAD(&clear_hash);
6627 key.flags = end; /* overload flags, as it is unsigned long */
6629 mutex_lock(&ftrace_lock);
6632 * If we are freeing module init memory, then check if
6633 * any tracer is active. If so, we need to save a mapping of
6634 * the module functions being freed with the address.
6636 if (mod && ftrace_ops_list != &ftrace_list_end)
6637 mod_map = allocate_ftrace_mod_map(mod, start, end);
6639 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
6640 if (end < pg->records[0].ip ||
6641 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
6644 rec = bsearch(&key, pg->records, pg->index,
6645 sizeof(struct dyn_ftrace),
6650 /* rec will be cleared from hashes after ftrace_lock unlock */
6651 add_to_clear_hash_list(&clear_hash, rec);
6654 save_ftrace_mod_rec(mod_map, rec);
6657 ftrace_update_tot_cnt--;
6659 *last_pg = pg->next;
6660 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
6661 free_pages((unsigned long)pg->records, order);
6662 ftrace_number_of_pages -= 1 << order;
6663 ftrace_number_of_groups--;
6665 pg = container_of(last_pg, struct ftrace_page, next);
6670 memmove(rec, rec + 1,
6671 (pg->index - (rec - pg->records)) * sizeof(*rec));
6672 /* More than one function may be in this block */
6675 mutex_unlock(&ftrace_lock);
6677 list_for_each_entry_safe(func, func_next, &clear_hash, list) {
6678 clear_func_from_hashes(func);
6683 void __init ftrace_free_init_mem(void)
6685 void *start = (void *)(&__init_begin);
6686 void *end = (void *)(&__init_end);
6688 ftrace_free_mem(NULL, start, end);
6691 void __init ftrace_init(void)
6693 extern unsigned long __start_mcount_loc[];
6694 extern unsigned long __stop_mcount_loc[];
6695 unsigned long count, flags;
6698 local_irq_save(flags);
6699 ret = ftrace_dyn_arch_init();
6700 local_irq_restore(flags);
6704 count = __stop_mcount_loc - __start_mcount_loc;
6706 pr_info("ftrace: No functions to be traced?\n");
6710 pr_info("ftrace: allocating %ld entries in %ld pages\n",
6711 count, count / ENTRIES_PER_PAGE + 1);
6713 last_ftrace_enabled = ftrace_enabled = 1;
6715 ret = ftrace_process_locs(NULL,
6719 pr_info("ftrace: allocated %ld pages with %ld groups\n",
6720 ftrace_number_of_pages, ftrace_number_of_groups);
6722 set_ftrace_early_filters();
6726 ftrace_disabled = 1;
6729 /* Do nothing if arch does not support this */
6730 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
6734 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6736 arch_ftrace_update_trampoline(ops);
6739 void ftrace_init_trace_array(struct trace_array *tr)
6741 INIT_LIST_HEAD(&tr->func_probes);
6742 INIT_LIST_HEAD(&tr->mod_trace);
6743 INIT_LIST_HEAD(&tr->mod_notrace);
6747 struct ftrace_ops global_ops = {
6748 .func = ftrace_stub,
6749 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
6750 FTRACE_OPS_FL_INITIALIZED |
6754 static int __init ftrace_nodyn_init(void)
6759 core_initcall(ftrace_nodyn_init);
6761 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
6762 static inline void ftrace_startup_enable(int command) { }
6763 static inline void ftrace_startup_all(int command) { }
6765 # define ftrace_startup_sysctl() do { } while (0)
6766 # define ftrace_shutdown_sysctl() do { } while (0)
6768 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6772 #endif /* CONFIG_DYNAMIC_FTRACE */
6774 __init void ftrace_init_global_array_ops(struct trace_array *tr)
6776 tr->ops = &global_ops;
6777 tr->ops->private = tr;
6778 ftrace_init_trace_array(tr);
6781 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
6783 /* If we filter on pids, update to use the pid function */
6784 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
6785 if (WARN_ON(tr->ops->func != ftrace_stub))
6786 printk("ftrace ops had %pS for function\n",
6789 tr->ops->func = func;
6790 tr->ops->private = tr;
6793 void ftrace_reset_array_ops(struct trace_array *tr)
6795 tr->ops->func = ftrace_stub;
6798 static nokprobe_inline void
6799 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6800 struct ftrace_ops *ignored, struct pt_regs *regs)
6802 struct ftrace_ops *op;
6805 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
6810 * Some of the ops may be dynamically allocated,
6811 * they must be freed after a synchronize_rcu().
6813 preempt_disable_notrace();
6815 do_for_each_ftrace_op(op, ftrace_ops_list) {
6816 /* Stub functions don't need to be called nor tested */
6817 if (op->flags & FTRACE_OPS_FL_STUB)
6820 * Check the following for each ops before calling their func:
6821 * if RCU flag is set, then rcu_is_watching() must be true
6822 * if PER_CPU is set, then ftrace_function_local_disable()
6824 * Otherwise test if the ip matches the ops filter
6826 * If any of the above fails then the op->func() is not executed.
6828 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
6829 ftrace_ops_test(op, ip, regs)) {
6830 if (FTRACE_WARN_ON(!op->func)) {
6831 pr_warn("op=%p %pS\n", op, op);
6834 op->func(ip, parent_ip, op, regs);
6836 } while_for_each_ftrace_op(op);
6838 preempt_enable_notrace();
6839 trace_clear_recursion(bit);
6843 * Some archs only support passing ip and parent_ip. Even though
6844 * the list function ignores the op parameter, we do not want any
6845 * C side effects, where a function is called without the caller
6846 * sending a third parameter.
6847 * Archs are to support both the regs and ftrace_ops at the same time.
6848 * If they support ftrace_ops, it is assumed they support regs.
6849 * If call backs want to use regs, they must either check for regs
6850 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
6851 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
6852 * An architecture can pass partial regs with ftrace_ops and still
6853 * set the ARCH_SUPPORTS_FTRACE_OPS.
6855 #if ARCH_SUPPORTS_FTRACE_OPS
6856 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6857 struct ftrace_ops *op, struct pt_regs *regs)
6859 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
6861 NOKPROBE_SYMBOL(ftrace_ops_list_func);
6863 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
6865 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
6867 NOKPROBE_SYMBOL(ftrace_ops_no_ops);
6871 * If there's only one function registered but it does not support
6872 * recursion, needs RCU protection and/or requires per cpu handling, then
6873 * this function will be called by the mcount trampoline.
6875 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
6876 struct ftrace_ops *op, struct pt_regs *regs)
6880 if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching())
6883 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
6887 preempt_disable_notrace();
6889 op->func(ip, parent_ip, op, regs);
6891 preempt_enable_notrace();
6892 trace_clear_recursion(bit);
6894 NOKPROBE_SYMBOL(ftrace_ops_assist_func);
6897 * ftrace_ops_get_func - get the function a trampoline should call
6898 * @ops: the ops to get the function for
6900 * Normally the mcount trampoline will call the ops->func, but there
6901 * are times that it should not. For example, if the ops does not
6902 * have its own recursion protection, then it should call the
6903 * ftrace_ops_assist_func() instead.
6905 * Returns the function that the trampoline should call for @ops.
6907 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
6910 * If the function does not handle recursion, needs to be RCU safe,
6911 * or does per cpu logic, then we need to call the assist handler.
6913 if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
6914 ops->flags & FTRACE_OPS_FL_RCU)
6915 return ftrace_ops_assist_func;
6921 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
6922 struct task_struct *prev, struct task_struct *next)
6924 struct trace_array *tr = data;
6925 struct trace_pid_list *pid_list;
6926 struct trace_pid_list *no_pid_list;
6928 pid_list = rcu_dereference_sched(tr->function_pids);
6929 no_pid_list = rcu_dereference_sched(tr->function_no_pids);
6931 if (trace_ignore_this_task(pid_list, no_pid_list, next))
6932 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
6935 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
6940 ftrace_pid_follow_sched_process_fork(void *data,
6941 struct task_struct *self,
6942 struct task_struct *task)
6944 struct trace_pid_list *pid_list;
6945 struct trace_array *tr = data;
6947 pid_list = rcu_dereference_sched(tr->function_pids);
6948 trace_filter_add_remove_task(pid_list, self, task);
6950 pid_list = rcu_dereference_sched(tr->function_no_pids);
6951 trace_filter_add_remove_task(pid_list, self, task);
6955 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
6957 struct trace_pid_list *pid_list;
6958 struct trace_array *tr = data;
6960 pid_list = rcu_dereference_sched(tr->function_pids);
6961 trace_filter_add_remove_task(pid_list, NULL, task);
6963 pid_list = rcu_dereference_sched(tr->function_no_pids);
6964 trace_filter_add_remove_task(pid_list, NULL, task);
6967 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
6970 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6972 register_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit,
6975 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6977 unregister_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit,
6982 static void clear_ftrace_pids(struct trace_array *tr, int type)
6984 struct trace_pid_list *pid_list;
6985 struct trace_pid_list *no_pid_list;
6988 pid_list = rcu_dereference_protected(tr->function_pids,
6989 lockdep_is_held(&ftrace_lock));
6990 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
6991 lockdep_is_held(&ftrace_lock));
6993 /* Make sure there's something to do */
6994 if (!pid_type_enabled(type, pid_list, no_pid_list))
6997 /* See if the pids still need to be checked after this */
6998 if (!still_need_pid_events(type, pid_list, no_pid_list)) {
6999 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7000 for_each_possible_cpu(cpu)
7001 per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
7004 if (type & TRACE_PIDS)
7005 rcu_assign_pointer(tr->function_pids, NULL);
7007 if (type & TRACE_NO_PIDS)
7008 rcu_assign_pointer(tr->function_no_pids, NULL);
7010 /* Wait till all users are no longer using pid filtering */
7013 if ((type & TRACE_PIDS) && pid_list)
7014 trace_free_pid_list(pid_list);
7016 if ((type & TRACE_NO_PIDS) && no_pid_list)
7017 trace_free_pid_list(no_pid_list);
7020 void ftrace_clear_pids(struct trace_array *tr)
7022 mutex_lock(&ftrace_lock);
7024 clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
7026 mutex_unlock(&ftrace_lock);
7029 static void ftrace_pid_reset(struct trace_array *tr, int type)
7031 mutex_lock(&ftrace_lock);
7032 clear_ftrace_pids(tr, type);
7034 ftrace_update_pid_func();
7035 ftrace_startup_all(0);
7037 mutex_unlock(&ftrace_lock);
7040 /* Greater than any max PID */
7041 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
7043 static void *fpid_start(struct seq_file *m, loff_t *pos)
7046 struct trace_pid_list *pid_list;
7047 struct trace_array *tr = m->private;
7049 mutex_lock(&ftrace_lock);
7050 rcu_read_lock_sched();
7052 pid_list = rcu_dereference_sched(tr->function_pids);
7055 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7057 return trace_pid_start(pid_list, pos);
7060 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
7062 struct trace_array *tr = m->private;
7063 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
7065 if (v == FTRACE_NO_PIDS) {
7069 return trace_pid_next(pid_list, v, pos);
7072 static void fpid_stop(struct seq_file *m, void *p)
7075 rcu_read_unlock_sched();
7076 mutex_unlock(&ftrace_lock);
7079 static int fpid_show(struct seq_file *m, void *v)
7081 if (v == FTRACE_NO_PIDS) {
7082 seq_puts(m, "no pid\n");
7086 return trace_pid_show(m, v);
7089 static const struct seq_operations ftrace_pid_sops = {
7090 .start = fpid_start,
7096 static void *fnpid_start(struct seq_file *m, loff_t *pos)
7099 struct trace_pid_list *pid_list;
7100 struct trace_array *tr = m->private;
7102 mutex_lock(&ftrace_lock);
7103 rcu_read_lock_sched();
7105 pid_list = rcu_dereference_sched(tr->function_no_pids);
7108 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7110 return trace_pid_start(pid_list, pos);
7113 static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
7115 struct trace_array *tr = m->private;
7116 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
7118 if (v == FTRACE_NO_PIDS) {
7122 return trace_pid_next(pid_list, v, pos);
7125 static const struct seq_operations ftrace_no_pid_sops = {
7126 .start = fnpid_start,
7132 static int pid_open(struct inode *inode, struct file *file, int type)
7134 const struct seq_operations *seq_ops;
7135 struct trace_array *tr = inode->i_private;
7139 ret = tracing_check_open_get_tr(tr);
7143 if ((file->f_mode & FMODE_WRITE) &&
7144 (file->f_flags & O_TRUNC))
7145 ftrace_pid_reset(tr, type);
7149 seq_ops = &ftrace_pid_sops;
7152 seq_ops = &ftrace_no_pid_sops;
7156 ret = seq_open(file, seq_ops);
7158 trace_array_put(tr);
7160 m = file->private_data;
7161 /* copy tr over to seq ops */
7169 ftrace_pid_open(struct inode *inode, struct file *file)
7171 return pid_open(inode, file, TRACE_PIDS);
7175 ftrace_no_pid_open(struct inode *inode, struct file *file)
7177 return pid_open(inode, file, TRACE_NO_PIDS);
7180 static void ignore_task_cpu(void *data)
7182 struct trace_array *tr = data;
7183 struct trace_pid_list *pid_list;
7184 struct trace_pid_list *no_pid_list;
7187 * This function is called by on_each_cpu() while the
7188 * event_mutex is held.
7190 pid_list = rcu_dereference_protected(tr->function_pids,
7191 mutex_is_locked(&ftrace_lock));
7192 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7193 mutex_is_locked(&ftrace_lock));
7195 if (trace_ignore_this_task(pid_list, no_pid_list, current))
7196 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7199 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7204 pid_write(struct file *filp, const char __user *ubuf,
7205 size_t cnt, loff_t *ppos, int type)
7207 struct seq_file *m = filp->private_data;
7208 struct trace_array *tr = m->private;
7209 struct trace_pid_list *filtered_pids;
7210 struct trace_pid_list *other_pids;
7211 struct trace_pid_list *pid_list;
7217 mutex_lock(&ftrace_lock);
7221 filtered_pids = rcu_dereference_protected(tr->function_pids,
7222 lockdep_is_held(&ftrace_lock));
7223 other_pids = rcu_dereference_protected(tr->function_no_pids,
7224 lockdep_is_held(&ftrace_lock));
7227 filtered_pids = rcu_dereference_protected(tr->function_no_pids,
7228 lockdep_is_held(&ftrace_lock));
7229 other_pids = rcu_dereference_protected(tr->function_pids,
7230 lockdep_is_held(&ftrace_lock));
7234 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
7240 rcu_assign_pointer(tr->function_pids, pid_list);
7243 rcu_assign_pointer(tr->function_no_pids, pid_list);
7248 if (filtered_pids) {
7250 trace_free_pid_list(filtered_pids);
7251 } else if (pid_list && !other_pids) {
7252 /* Register a probe to set whether to ignore the tracing of a task */
7253 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7257 * Ignoring of pids is done at task switch. But we have to
7258 * check for those tasks that are currently running.
7259 * Always do this in case a pid was appended or removed.
7261 on_each_cpu(ignore_task_cpu, tr, 1);
7263 ftrace_update_pid_func();
7264 ftrace_startup_all(0);
7266 mutex_unlock(&ftrace_lock);
7275 ftrace_pid_write(struct file *filp, const char __user *ubuf,
7276 size_t cnt, loff_t *ppos)
7278 return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
7282 ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
7283 size_t cnt, loff_t *ppos)
7285 return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
7289 ftrace_pid_release(struct inode *inode, struct file *file)
7291 struct trace_array *tr = inode->i_private;
7293 trace_array_put(tr);
7295 return seq_release(inode, file);
7298 static const struct file_operations ftrace_pid_fops = {
7299 .open = ftrace_pid_open,
7300 .write = ftrace_pid_write,
7302 .llseek = tracing_lseek,
7303 .release = ftrace_pid_release,
7306 static const struct file_operations ftrace_no_pid_fops = {
7307 .open = ftrace_no_pid_open,
7308 .write = ftrace_no_pid_write,
7310 .llseek = tracing_lseek,
7311 .release = ftrace_pid_release,
7314 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
7316 trace_create_file("set_ftrace_pid", 0644, d_tracer,
7317 tr, &ftrace_pid_fops);
7318 trace_create_file("set_ftrace_notrace_pid", 0644, d_tracer,
7319 tr, &ftrace_no_pid_fops);
7322 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
7323 struct dentry *d_tracer)
7325 /* Only the top level directory has the dyn_tracefs and profile */
7326 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
7328 ftrace_init_dyn_tracefs(d_tracer);
7329 ftrace_profile_tracefs(d_tracer);
7333 * ftrace_kill - kill ftrace
7335 * This function should be used by panic code. It stops ftrace
7336 * but in a not so nice way. If you need to simply kill ftrace
7337 * from a non-atomic section, use ftrace_kill.
7339 void ftrace_kill(void)
7341 ftrace_disabled = 1;
7343 ftrace_trace_function = ftrace_stub;
7347 * Test if ftrace is dead or not.
7349 int ftrace_is_dead(void)
7351 return ftrace_disabled;
7355 * register_ftrace_function - register a function for profiling
7356 * @ops - ops structure that holds the function for profiling.
7358 * Register a function to be called by all functions in the
7361 * Note: @ops->func and all the functions it calls must be labeled
7362 * with "notrace", otherwise it will go into a
7365 int register_ftrace_function(struct ftrace_ops *ops)
7369 ftrace_ops_init(ops);
7371 mutex_lock(&ftrace_lock);
7373 ret = ftrace_startup(ops, 0);
7375 mutex_unlock(&ftrace_lock);
7379 EXPORT_SYMBOL_GPL(register_ftrace_function);
7382 * unregister_ftrace_function - unregister a function for profiling.
7383 * @ops - ops structure that holds the function to unregister
7385 * Unregister a function that was added to be called by ftrace profiling.
7387 int unregister_ftrace_function(struct ftrace_ops *ops)
7391 mutex_lock(&ftrace_lock);
7392 ret = ftrace_shutdown(ops, 0);
7393 mutex_unlock(&ftrace_lock);
7397 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
7399 static bool is_permanent_ops_registered(void)
7401 struct ftrace_ops *op;
7403 do_for_each_ftrace_op(op, ftrace_ops_list) {
7404 if (op->flags & FTRACE_OPS_FL_PERMANENT)
7406 } while_for_each_ftrace_op(op);
7412 ftrace_enable_sysctl(struct ctl_table *table, int write,
7413 void __user *buffer, size_t *lenp,
7418 mutex_lock(&ftrace_lock);
7420 if (unlikely(ftrace_disabled))
7423 ret = proc_dointvec(table, write, buffer, lenp, ppos);
7425 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
7428 if (ftrace_enabled) {
7430 /* we are starting ftrace again */
7431 if (rcu_dereference_protected(ftrace_ops_list,
7432 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
7433 update_ftrace_function();
7435 ftrace_startup_sysctl();
7438 if (is_permanent_ops_registered()) {
7439 ftrace_enabled = true;
7444 /* stopping ftrace calls (just send to ftrace_stub) */
7445 ftrace_trace_function = ftrace_stub;
7447 ftrace_shutdown_sysctl();
7450 last_ftrace_enabled = !!ftrace_enabled;
7452 mutex_unlock(&ftrace_lock);