2 * Kprobes-based tracing events
4 * Created by Masami Hiramatsu <mhiramat@redhat.com>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 #include <linux/module.h>
21 #include <linux/uaccess.h>
23 #include "trace_probe.h"
25 #define KPROBE_EVENT_SYSTEM "kprobes"
28 * Kprobe event core functions
31 struct list_head list;
32 struct kretprobe rp; /* Use rp.kp for kprobe use */
34 const char *symbol; /* symbol name */
35 struct trace_probe tp;
38 #define SIZEOF_TRACE_KPROBE(n) \
39 (offsetof(struct trace_kprobe, tp.args) + \
40 (sizeof(struct probe_arg) * (n)))
43 static __kprobes bool trace_kprobe_is_return(struct trace_kprobe *tk)
45 return tk->rp.handler != NULL;
48 static __kprobes const char *trace_kprobe_symbol(struct trace_kprobe *tk)
50 return tk->symbol ? tk->symbol : "unknown";
53 static __kprobes unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
55 return tk->rp.kp.offset;
58 static __kprobes bool trace_kprobe_has_gone(struct trace_kprobe *tk)
60 return !!(kprobe_gone(&tk->rp.kp));
63 static __kprobes bool trace_kprobe_within_module(struct trace_kprobe *tk,
66 int len = strlen(mod->name);
67 const char *name = trace_kprobe_symbol(tk);
68 return strncmp(mod->name, name, len) == 0 && name[len] == ':';
71 static __kprobes bool trace_kprobe_is_on_module(struct trace_kprobe *tk)
73 return !!strchr(trace_kprobe_symbol(tk), ':');
76 static int register_kprobe_event(struct trace_kprobe *tk);
77 static int unregister_kprobe_event(struct trace_kprobe *tk);
79 static DEFINE_MUTEX(probe_lock);
80 static LIST_HEAD(probe_list);
82 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
83 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
84 struct pt_regs *regs);
86 /* Memory fetching by symbol */
93 unsigned long update_symbol_cache(struct symbol_cache *sc)
95 sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
98 sc->addr += sc->offset;
103 void free_symbol_cache(struct symbol_cache *sc)
109 struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
111 struct symbol_cache *sc;
113 if (!sym || strlen(sym) == 0)
116 sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
120 sc->symbol = kstrdup(sym, GFP_KERNEL);
126 update_symbol_cache(sc);
132 * Kprobes-specific fetch functions
134 #define DEFINE_FETCH_stack(type) \
135 static __kprobes void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,\
136 void *offset, void *dest) \
138 *(type *)dest = (type)regs_get_kernel_stack_nth(regs, \
139 (unsigned int)((unsigned long)offset)); \
141 DEFINE_BASIC_FETCH_FUNCS(stack)
142 /* No string on the stack entry */
143 #define fetch_stack_string NULL
144 #define fetch_stack_string_size NULL
146 #define DEFINE_FETCH_memory(type) \
147 static __kprobes void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,\
148 void *addr, void *dest) \
151 if (probe_kernel_address(addr, retval)) \
154 *(type *)dest = retval; \
156 DEFINE_BASIC_FETCH_FUNCS(memory)
158 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
159 * length and relative data location.
161 static __kprobes void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
162 void *addr, void *dest)
165 int maxlen = get_rloc_len(*(u32 *)dest);
166 u8 *dst = get_rloc_data(dest);
168 mm_segment_t old_fs = get_fs();
174 * Try to get string again, since the string can be changed while
181 ret = __copy_from_user_inatomic(dst++, src++, 1);
182 while (dst[-1] && ret == 0 && src - (u8 *)addr < maxlen);
188 if (ret < 0) { /* Failed to fetch string */
189 ((u8 *)get_rloc_data(dest))[0] = '\0';
190 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
192 *(u32 *)dest = make_data_rloc(src - (u8 *)addr,
193 get_rloc_offs(*(u32 *)dest));
197 /* Return the length of string -- including null terminal byte */
198 static __kprobes void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
199 void *addr, void *dest)
210 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
212 } while (c && ret == 0 && len < MAX_STRING_SIZE);
217 if (ret < 0) /* Failed to check the length */
223 #define DEFINE_FETCH_symbol(type) \
224 __kprobes void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs, \
225 void *data, void *dest) \
227 struct symbol_cache *sc = data; \
229 fetch_memory_##type(regs, (void *)sc->addr, dest); \
233 DEFINE_BASIC_FETCH_FUNCS(symbol)
234 DEFINE_FETCH_symbol(string)
235 DEFINE_FETCH_symbol(string_size)
237 /* kprobes don't support file_offset fetch methods */
238 #define fetch_file_offset_u8 NULL
239 #define fetch_file_offset_u16 NULL
240 #define fetch_file_offset_u32 NULL
241 #define fetch_file_offset_u64 NULL
242 #define fetch_file_offset_string NULL
243 #define fetch_file_offset_string_size NULL
245 /* Fetch type information table */
246 const struct fetch_type kprobes_fetch_type_table[] = {
248 [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
249 sizeof(u32), 1, "__data_loc char[]"),
250 [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
251 string_size, sizeof(u32), 0, "u32"),
253 ASSIGN_FETCH_TYPE(u8, u8, 0),
254 ASSIGN_FETCH_TYPE(u16, u16, 0),
255 ASSIGN_FETCH_TYPE(u32, u32, 0),
256 ASSIGN_FETCH_TYPE(u64, u64, 0),
257 ASSIGN_FETCH_TYPE(s8, u8, 1),
258 ASSIGN_FETCH_TYPE(s16, u16, 1),
259 ASSIGN_FETCH_TYPE(s32, u32, 1),
260 ASSIGN_FETCH_TYPE(s64, u64, 1),
262 ASSIGN_FETCH_TYPE_END
266 * Allocate new trace_probe and initialize it (including kprobes).
268 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
273 int nargs, bool is_return)
275 struct trace_kprobe *tk;
278 tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
283 tk->symbol = kstrdup(symbol, GFP_KERNEL);
286 tk->rp.kp.symbol_name = tk->symbol;
287 tk->rp.kp.offset = offs;
289 tk->rp.kp.addr = addr;
292 tk->rp.handler = kretprobe_dispatcher;
294 tk->rp.kp.pre_handler = kprobe_dispatcher;
296 if (!event || !is_good_name(event)) {
301 tk->tp.call.class = &tk->tp.class;
302 tk->tp.call.name = kstrdup(event, GFP_KERNEL);
303 if (!tk->tp.call.name)
306 if (!group || !is_good_name(group)) {
311 tk->tp.class.system = kstrdup(group, GFP_KERNEL);
312 if (!tk->tp.class.system)
315 INIT_LIST_HEAD(&tk->list);
316 INIT_LIST_HEAD(&tk->tp.files);
319 kfree(tk->tp.call.name);
325 static void free_trace_kprobe(struct trace_kprobe *tk)
329 for (i = 0; i < tk->tp.nr_args; i++)
330 traceprobe_free_probe_arg(&tk->tp.args[i]);
332 kfree(tk->tp.call.class->system);
333 kfree(tk->tp.call.name);
338 static struct trace_kprobe *find_trace_kprobe(const char *event,
341 struct trace_kprobe *tk;
343 list_for_each_entry(tk, &probe_list, list)
344 if (strcmp(tk->tp.call.name, event) == 0 &&
345 strcmp(tk->tp.call.class->system, group) == 0)
352 * if the file is NULL, enable "perf" handler, or enable "trace" handler.
355 enable_trace_kprobe(struct trace_kprobe *tk, struct ftrace_event_file *file)
360 struct event_file_link *link;
362 link = kmalloc(sizeof(*link), GFP_KERNEL);
369 list_add_tail_rcu(&link->list, &tk->tp.files);
371 tk->tp.flags |= TP_FLAG_TRACE;
373 tk->tp.flags |= TP_FLAG_PROFILE;
375 if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
376 if (trace_kprobe_is_return(tk))
377 ret = enable_kretprobe(&tk->rp);
379 ret = enable_kprobe(&tk->rp.kp);
386 * Disable trace_probe
387 * if the file is NULL, disable "perf" handler, or disable "trace" handler.
390 disable_trace_kprobe(struct trace_kprobe *tk, struct ftrace_event_file *file)
392 struct event_file_link *link = NULL;
397 link = find_event_file_link(&tk->tp, file);
403 list_del_rcu(&link->list);
405 if (!list_empty(&tk->tp.files))
408 tk->tp.flags &= ~TP_FLAG_TRACE;
410 tk->tp.flags &= ~TP_FLAG_PROFILE;
412 if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) {
413 if (trace_kprobe_is_return(tk))
414 disable_kretprobe(&tk->rp);
416 disable_kprobe(&tk->rp.kp);
422 * Synchronize with kprobe_trace_func/kretprobe_trace_func
423 * to ensure disabled (all running handlers are finished).
424 * This is not only for kfree(), but also the caller,
425 * trace_remove_event_call() supposes it for releasing
426 * event_call related objects, which will be accessed in
427 * the kprobe_trace_func/kretprobe_trace_func.
430 kfree(link); /* Ignored if link == NULL */
436 /* Internal register function - just handle k*probes and flags */
437 static int __register_trace_kprobe(struct trace_kprobe *tk)
441 if (trace_probe_is_registered(&tk->tp))
444 for (i = 0; i < tk->tp.nr_args; i++)
445 traceprobe_update_arg(&tk->tp.args[i]);
447 /* Set/clear disabled flag according to tp->flag */
448 if (trace_probe_is_enabled(&tk->tp))
449 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
451 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
453 if (trace_kprobe_is_return(tk))
454 ret = register_kretprobe(&tk->rp);
456 ret = register_kprobe(&tk->rp.kp);
459 tk->tp.flags |= TP_FLAG_REGISTERED;
461 pr_warning("Could not insert probe at %s+%lu: %d\n",
462 trace_kprobe_symbol(tk), trace_kprobe_offset(tk), ret);
463 if (ret == -ENOENT && trace_kprobe_is_on_module(tk)) {
464 pr_warning("This probe might be able to register after"
465 "target module is loaded. Continue.\n");
467 } else if (ret == -EILSEQ) {
468 pr_warning("Probing address(0x%p) is not an "
469 "instruction boundary.\n",
478 /* Internal unregister function - just handle k*probes and flags */
479 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
481 if (trace_probe_is_registered(&tk->tp)) {
482 if (trace_kprobe_is_return(tk))
483 unregister_kretprobe(&tk->rp);
485 unregister_kprobe(&tk->rp.kp);
486 tk->tp.flags &= ~TP_FLAG_REGISTERED;
487 /* Cleanup kprobe for reuse */
488 if (tk->rp.kp.symbol_name)
489 tk->rp.kp.addr = NULL;
493 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
494 static int unregister_trace_kprobe(struct trace_kprobe *tk)
496 /* Enabled event can not be unregistered */
497 if (trace_probe_is_enabled(&tk->tp))
500 /* Will fail if probe is being used by ftrace or perf */
501 if (unregister_kprobe_event(tk))
504 __unregister_trace_kprobe(tk);
510 /* Register a trace_probe and probe_event */
511 static int register_trace_kprobe(struct trace_kprobe *tk)
513 struct trace_kprobe *old_tk;
516 mutex_lock(&probe_lock);
518 /* Delete old (same name) event if exist */
519 old_tk = find_trace_kprobe(tk->tp.call.name, tk->tp.call.class->system);
521 ret = unregister_trace_kprobe(old_tk);
524 free_trace_kprobe(old_tk);
527 /* Register new event */
528 ret = register_kprobe_event(tk);
530 pr_warning("Failed to register probe event(%d)\n", ret);
534 /* Register k*probe */
535 ret = __register_trace_kprobe(tk);
537 unregister_kprobe_event(tk);
539 list_add_tail(&tk->list, &probe_list);
542 mutex_unlock(&probe_lock);
546 /* Module notifier call back, checking event on the module */
547 static int trace_kprobe_module_callback(struct notifier_block *nb,
548 unsigned long val, void *data)
550 struct module *mod = data;
551 struct trace_kprobe *tk;
554 if (val != MODULE_STATE_COMING)
557 /* Update probes on coming module */
558 mutex_lock(&probe_lock);
559 list_for_each_entry(tk, &probe_list, list) {
560 if (trace_kprobe_within_module(tk, mod)) {
561 /* Don't need to check busy - this should have gone. */
562 __unregister_trace_kprobe(tk);
563 ret = __register_trace_kprobe(tk);
565 pr_warning("Failed to re-register probe %s on"
567 tk->tp.call.name, mod->name, ret);
570 mutex_unlock(&probe_lock);
575 static struct notifier_block trace_kprobe_module_nb = {
576 .notifier_call = trace_kprobe_module_callback,
577 .priority = 1 /* Invoked after kprobe module callback */
580 static int create_trace_kprobe(int argc, char **argv)
584 * - Add kprobe: p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
585 * - Add kretprobe: r[:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
587 * $retval : fetch return value
588 * $stack : fetch stack address
589 * $stackN : fetch Nth of stack (N:0-)
590 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
591 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
592 * %REG : fetch register REG
593 * Dereferencing memory fetch:
594 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
595 * Alias name of args:
596 * NAME=FETCHARG : set NAME as alias of FETCHARG.
598 * FETCHARG:TYPE : use TYPE instead of unsigned long.
600 struct trace_kprobe *tk;
602 bool is_return = false, is_delete = false;
603 char *symbol = NULL, *event = NULL, *group = NULL;
605 unsigned long offset = 0;
607 char buf[MAX_EVENT_NAME_LEN];
609 /* argc must be >= 1 */
610 if (argv[0][0] == 'p')
612 else if (argv[0][0] == 'r')
614 else if (argv[0][0] == '-')
617 pr_info("Probe definition must be started with 'p', 'r' or"
622 if (argv[0][1] == ':') {
624 if (strchr(event, '/')) {
626 event = strchr(group, '/') + 1;
628 if (strlen(group) == 0) {
629 pr_info("Group name is not specified\n");
633 if (strlen(event) == 0) {
634 pr_info("Event name is not specified\n");
639 group = KPROBE_EVENT_SYSTEM;
643 pr_info("Delete command needs an event name.\n");
646 mutex_lock(&probe_lock);
647 tk = find_trace_kprobe(event, group);
649 mutex_unlock(&probe_lock);
650 pr_info("Event %s/%s doesn't exist.\n", group, event);
653 /* delete an event */
654 ret = unregister_trace_kprobe(tk);
656 free_trace_kprobe(tk);
657 mutex_unlock(&probe_lock);
662 pr_info("Probe point is not specified.\n");
665 if (isdigit(argv[1][0])) {
667 pr_info("Return probe point must be a symbol.\n");
670 /* an address specified */
671 ret = kstrtoul(&argv[1][0], 0, (unsigned long *)&addr);
673 pr_info("Failed to parse address.\n");
677 /* a symbol specified */
679 /* TODO: support .init module functions */
680 ret = traceprobe_split_symbol_offset(symbol, &offset);
682 pr_info("Failed to parse symbol.\n");
685 if (offset && is_return) {
686 pr_info("Return probe must be used without offset.\n");
690 argc -= 2; argv += 2;
694 /* Make a new event name */
696 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
697 is_return ? 'r' : 'p', symbol, offset);
699 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
700 is_return ? 'r' : 'p', addr);
703 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, argc,
706 pr_info("Failed to allocate trace_probe.(%d)\n",
711 /* parse arguments */
713 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
714 struct probe_arg *parg = &tk->tp.args[i];
716 /* Increment count for freeing args in error case */
719 /* Parse argument name */
720 arg = strchr(argv[i], '=');
723 parg->name = kstrdup(argv[i], GFP_KERNEL);
726 /* If argument name is omitted, set "argN" */
727 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
728 parg->name = kstrdup(buf, GFP_KERNEL);
732 pr_info("Failed to allocate argument[%d] name.\n", i);
737 if (!is_good_name(parg->name)) {
738 pr_info("Invalid argument[%d] name: %s\n",
744 if (traceprobe_conflict_field_name(parg->name,
746 pr_info("Argument[%d] name '%s' conflicts with "
747 "another field.\n", i, argv[i]);
752 /* Parse fetch argument */
753 ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
756 pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
761 ret = register_trace_kprobe(tk);
767 free_trace_kprobe(tk);
771 static int release_all_trace_kprobes(void)
773 struct trace_kprobe *tk;
776 mutex_lock(&probe_lock);
777 /* Ensure no probe is in use. */
778 list_for_each_entry(tk, &probe_list, list)
779 if (trace_probe_is_enabled(&tk->tp)) {
783 /* TODO: Use batch unregistration */
784 while (!list_empty(&probe_list)) {
785 tk = list_entry(probe_list.next, struct trace_kprobe, list);
786 ret = unregister_trace_kprobe(tk);
789 free_trace_kprobe(tk);
793 mutex_unlock(&probe_lock);
798 /* Probes listing interfaces */
799 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
801 mutex_lock(&probe_lock);
802 return seq_list_start(&probe_list, *pos);
805 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
807 return seq_list_next(v, &probe_list, pos);
810 static void probes_seq_stop(struct seq_file *m, void *v)
812 mutex_unlock(&probe_lock);
815 static int probes_seq_show(struct seq_file *m, void *v)
817 struct trace_kprobe *tk = v;
820 seq_printf(m, "%c", trace_kprobe_is_return(tk) ? 'r' : 'p');
821 seq_printf(m, ":%s/%s", tk->tp.call.class->system, tk->tp.call.name);
824 seq_printf(m, " 0x%p", tk->rp.kp.addr);
825 else if (tk->rp.kp.offset)
826 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
829 seq_printf(m, " %s", trace_kprobe_symbol(tk));
831 for (i = 0; i < tk->tp.nr_args; i++)
832 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
838 static const struct seq_operations probes_seq_op = {
839 .start = probes_seq_start,
840 .next = probes_seq_next,
841 .stop = probes_seq_stop,
842 .show = probes_seq_show
845 static int probes_open(struct inode *inode, struct file *file)
849 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
850 ret = release_all_trace_kprobes();
855 return seq_open(file, &probes_seq_op);
858 static ssize_t probes_write(struct file *file, const char __user *buffer,
859 size_t count, loff_t *ppos)
861 return traceprobe_probes_write(file, buffer, count, ppos,
862 create_trace_kprobe);
865 static const struct file_operations kprobe_events_ops = {
866 .owner = THIS_MODULE,
870 .release = seq_release,
871 .write = probes_write,
874 /* Probes profiling interfaces */
875 static int probes_profile_seq_show(struct seq_file *m, void *v)
877 struct trace_kprobe *tk = v;
879 seq_printf(m, " %-44s %15lu %15lu\n", tk->tp.call.name, tk->nhit,
885 static const struct seq_operations profile_seq_op = {
886 .start = probes_seq_start,
887 .next = probes_seq_next,
888 .stop = probes_seq_stop,
889 .show = probes_profile_seq_show
892 static int profile_open(struct inode *inode, struct file *file)
894 return seq_open(file, &profile_seq_op);
897 static const struct file_operations kprobe_profile_ops = {
898 .owner = THIS_MODULE,
899 .open = profile_open,
902 .release = seq_release,
906 static __kprobes void
907 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
908 struct ftrace_event_file *ftrace_file)
910 struct kprobe_trace_entry_head *entry;
911 struct ring_buffer_event *event;
912 struct ring_buffer *buffer;
914 unsigned long irq_flags;
915 struct ftrace_event_call *call = &tk->tp.call;
917 WARN_ON(call != ftrace_file->event_call);
919 if (ftrace_trigger_soft_disabled(ftrace_file))
922 local_save_flags(irq_flags);
923 pc = preempt_count();
925 dsize = __get_data_size(&tk->tp, regs);
926 size = sizeof(*entry) + tk->tp.size + dsize;
928 event = trace_event_buffer_lock_reserve(&buffer, ftrace_file,
930 size, irq_flags, pc);
934 entry = ring_buffer_event_data(event);
935 entry->ip = (unsigned long)tk->rp.kp.addr;
936 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
938 event_trigger_unlock_commit_regs(ftrace_file, buffer, event,
939 entry, irq_flags, pc, regs);
942 static __kprobes void
943 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
945 struct event_file_link *link;
947 list_for_each_entry_rcu(link, &tk->tp.files, list)
948 __kprobe_trace_func(tk, regs, link->file);
951 /* Kretprobe handler */
952 static __kprobes void
953 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
954 struct pt_regs *regs,
955 struct ftrace_event_file *ftrace_file)
957 struct kretprobe_trace_entry_head *entry;
958 struct ring_buffer_event *event;
959 struct ring_buffer *buffer;
961 unsigned long irq_flags;
962 struct ftrace_event_call *call = &tk->tp.call;
964 WARN_ON(call != ftrace_file->event_call);
966 if (ftrace_trigger_soft_disabled(ftrace_file))
969 local_save_flags(irq_flags);
970 pc = preempt_count();
972 dsize = __get_data_size(&tk->tp, regs);
973 size = sizeof(*entry) + tk->tp.size + dsize;
975 event = trace_event_buffer_lock_reserve(&buffer, ftrace_file,
977 size, irq_flags, pc);
981 entry = ring_buffer_event_data(event);
982 entry->func = (unsigned long)tk->rp.kp.addr;
983 entry->ret_ip = (unsigned long)ri->ret_addr;
984 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
986 event_trigger_unlock_commit_regs(ftrace_file, buffer, event,
987 entry, irq_flags, pc, regs);
990 static __kprobes void
991 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
992 struct pt_regs *regs)
994 struct event_file_link *link;
996 list_for_each_entry_rcu(link, &tk->tp.files, list)
997 __kretprobe_trace_func(tk, ri, regs, link->file);
1000 /* Event entry printers */
1001 static enum print_line_t
1002 print_kprobe_event(struct trace_iterator *iter, int flags,
1003 struct trace_event *event)
1005 struct kprobe_trace_entry_head *field;
1006 struct trace_seq *s = &iter->seq;
1007 struct trace_probe *tp;
1011 field = (struct kprobe_trace_entry_head *)iter->ent;
1012 tp = container_of(event, struct trace_probe, call.event);
1014 if (!trace_seq_printf(s, "%s: (", tp->call.name))
1017 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1020 if (!trace_seq_puts(s, ")"))
1023 data = (u8 *)&field[1];
1024 for (i = 0; i < tp->nr_args; i++)
1025 if (!tp->args[i].type->print(s, tp->args[i].name,
1026 data + tp->args[i].offset, field))
1029 if (!trace_seq_puts(s, "\n"))
1032 return TRACE_TYPE_HANDLED;
1034 return TRACE_TYPE_PARTIAL_LINE;
1037 static enum print_line_t
1038 print_kretprobe_event(struct trace_iterator *iter, int flags,
1039 struct trace_event *event)
1041 struct kretprobe_trace_entry_head *field;
1042 struct trace_seq *s = &iter->seq;
1043 struct trace_probe *tp;
1047 field = (struct kretprobe_trace_entry_head *)iter->ent;
1048 tp = container_of(event, struct trace_probe, call.event);
1050 if (!trace_seq_printf(s, "%s: (", tp->call.name))
1053 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1056 if (!trace_seq_puts(s, " <- "))
1059 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1062 if (!trace_seq_puts(s, ")"))
1065 data = (u8 *)&field[1];
1066 for (i = 0; i < tp->nr_args; i++)
1067 if (!tp->args[i].type->print(s, tp->args[i].name,
1068 data + tp->args[i].offset, field))
1071 if (!trace_seq_puts(s, "\n"))
1074 return TRACE_TYPE_HANDLED;
1076 return TRACE_TYPE_PARTIAL_LINE;
1080 static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
1083 struct kprobe_trace_entry_head field;
1084 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1086 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1087 /* Set argument names as fields */
1088 for (i = 0; i < tk->tp.nr_args; i++) {
1089 struct probe_arg *parg = &tk->tp.args[i];
1091 ret = trace_define_field(event_call, parg->type->fmttype,
1093 sizeof(field) + parg->offset,
1095 parg->type->is_signed,
1103 static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
1106 struct kretprobe_trace_entry_head field;
1107 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1109 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1110 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1111 /* Set argument names as fields */
1112 for (i = 0; i < tk->tp.nr_args; i++) {
1113 struct probe_arg *parg = &tk->tp.args[i];
1115 ret = trace_define_field(event_call, parg->type->fmttype,
1117 sizeof(field) + parg->offset,
1119 parg->type->is_signed,
1127 #ifdef CONFIG_PERF_EVENTS
1129 /* Kprobe profile handler */
1130 static __kprobes void
1131 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1133 struct ftrace_event_call *call = &tk->tp.call;
1134 struct kprobe_trace_entry_head *entry;
1135 struct hlist_head *head;
1136 int size, __size, dsize;
1139 head = this_cpu_ptr(call->perf_events);
1140 if (hlist_empty(head))
1143 dsize = __get_data_size(&tk->tp, regs);
1144 __size = sizeof(*entry) + tk->tp.size + dsize;
1145 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1146 size -= sizeof(u32);
1148 entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1152 entry->ip = (unsigned long)tk->rp.kp.addr;
1153 memset(&entry[1], 0, dsize);
1154 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1155 perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
1158 /* Kretprobe profile handler */
1159 static __kprobes void
1160 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1161 struct pt_regs *regs)
1163 struct ftrace_event_call *call = &tk->tp.call;
1164 struct kretprobe_trace_entry_head *entry;
1165 struct hlist_head *head;
1166 int size, __size, dsize;
1169 head = this_cpu_ptr(call->perf_events);
1170 if (hlist_empty(head))
1173 dsize = __get_data_size(&tk->tp, regs);
1174 __size = sizeof(*entry) + tk->tp.size + dsize;
1175 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1176 size -= sizeof(u32);
1178 entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1182 entry->func = (unsigned long)tk->rp.kp.addr;
1183 entry->ret_ip = (unsigned long)ri->ret_addr;
1184 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1185 perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
1187 #endif /* CONFIG_PERF_EVENTS */
1190 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1192 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1193 * lockless, but we can't race with this __init function.
1196 int kprobe_register(struct ftrace_event_call *event,
1197 enum trace_reg type, void *data)
1199 struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1200 struct ftrace_event_file *file = data;
1203 case TRACE_REG_REGISTER:
1204 return enable_trace_kprobe(tk, file);
1205 case TRACE_REG_UNREGISTER:
1206 return disable_trace_kprobe(tk, file);
1208 #ifdef CONFIG_PERF_EVENTS
1209 case TRACE_REG_PERF_REGISTER:
1210 return enable_trace_kprobe(tk, NULL);
1211 case TRACE_REG_PERF_UNREGISTER:
1212 return disable_trace_kprobe(tk, NULL);
1213 case TRACE_REG_PERF_OPEN:
1214 case TRACE_REG_PERF_CLOSE:
1215 case TRACE_REG_PERF_ADD:
1216 case TRACE_REG_PERF_DEL:
1224 int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1226 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1230 if (tk->tp.flags & TP_FLAG_TRACE)
1231 kprobe_trace_func(tk, regs);
1232 #ifdef CONFIG_PERF_EVENTS
1233 if (tk->tp.flags & TP_FLAG_PROFILE)
1234 kprobe_perf_func(tk, regs);
1236 return 0; /* We don't tweek kernel, so just return 0 */
1240 int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1242 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1246 if (tk->tp.flags & TP_FLAG_TRACE)
1247 kretprobe_trace_func(tk, ri, regs);
1248 #ifdef CONFIG_PERF_EVENTS
1249 if (tk->tp.flags & TP_FLAG_PROFILE)
1250 kretprobe_perf_func(tk, ri, regs);
1252 return 0; /* We don't tweek kernel, so just return 0 */
1255 static struct trace_event_functions kretprobe_funcs = {
1256 .trace = print_kretprobe_event
1259 static struct trace_event_functions kprobe_funcs = {
1260 .trace = print_kprobe_event
1263 static int register_kprobe_event(struct trace_kprobe *tk)
1265 struct ftrace_event_call *call = &tk->tp.call;
1268 /* Initialize ftrace_event_call */
1269 INIT_LIST_HEAD(&call->class->fields);
1270 if (trace_kprobe_is_return(tk)) {
1271 call->event.funcs = &kretprobe_funcs;
1272 call->class->define_fields = kretprobe_event_define_fields;
1274 call->event.funcs = &kprobe_funcs;
1275 call->class->define_fields = kprobe_event_define_fields;
1277 if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1279 ret = register_ftrace_event(&call->event);
1281 kfree(call->print_fmt);
1285 call->class->reg = kprobe_register;
1287 ret = trace_add_event_call(call);
1289 pr_info("Failed to register kprobe event: %s\n", call->name);
1290 kfree(call->print_fmt);
1291 unregister_ftrace_event(&call->event);
1296 static int unregister_kprobe_event(struct trace_kprobe *tk)
1300 /* tp->event is unregistered in trace_remove_event_call() */
1301 ret = trace_remove_event_call(&tk->tp.call);
1303 kfree(tk->tp.call.print_fmt);
1307 /* Make a debugfs interface for controlling probe points */
1308 static __init int init_kprobe_trace(void)
1310 struct dentry *d_tracer;
1311 struct dentry *entry;
1313 if (register_module_notifier(&trace_kprobe_module_nb))
1316 d_tracer = tracing_init_dentry();
1320 entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
1321 NULL, &kprobe_events_ops);
1323 /* Event list interface */
1325 pr_warning("Could not create debugfs "
1326 "'kprobe_events' entry\n");
1328 /* Profile interface */
1329 entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
1330 NULL, &kprobe_profile_ops);
1333 pr_warning("Could not create debugfs "
1334 "'kprobe_profile' entry\n");
1337 fs_initcall(init_kprobe_trace);
1340 #ifdef CONFIG_FTRACE_STARTUP_TEST
1343 * The "__used" keeps gcc from removing the function symbol
1344 * from the kallsyms table.
1346 static __used int kprobe_trace_selftest_target(int a1, int a2, int a3,
1347 int a4, int a5, int a6)
1349 return a1 + a2 + a3 + a4 + a5 + a6;
1352 static struct ftrace_event_file *
1353 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1355 struct ftrace_event_file *file;
1357 list_for_each_entry(file, &tr->events, list)
1358 if (file->event_call == &tk->tp.call)
1365 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1366 * stage, we can do this lockless.
1368 static __init int kprobe_trace_self_tests_init(void)
1371 int (*target)(int, int, int, int, int, int);
1372 struct trace_kprobe *tk;
1373 struct ftrace_event_file *file;
1375 target = kprobe_trace_selftest_target;
1377 pr_info("Testing kprobe tracing: ");
1379 ret = traceprobe_command("p:testprobe kprobe_trace_selftest_target "
1380 "$stack $stack0 +0($stack)",
1381 create_trace_kprobe);
1382 if (WARN_ON_ONCE(ret)) {
1383 pr_warn("error on probing function entry.\n");
1386 /* Enable trace point */
1387 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1388 if (WARN_ON_ONCE(tk == NULL)) {
1389 pr_warn("error on getting new probe.\n");
1392 file = find_trace_probe_file(tk, top_trace_array());
1393 if (WARN_ON_ONCE(file == NULL)) {
1394 pr_warn("error on getting probe file.\n");
1397 enable_trace_kprobe(tk, file);
1401 ret = traceprobe_command("r:testprobe2 kprobe_trace_selftest_target "
1402 "$retval", create_trace_kprobe);
1403 if (WARN_ON_ONCE(ret)) {
1404 pr_warn("error on probing function return.\n");
1407 /* Enable trace point */
1408 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1409 if (WARN_ON_ONCE(tk == NULL)) {
1410 pr_warn("error on getting 2nd new probe.\n");
1413 file = find_trace_probe_file(tk, top_trace_array());
1414 if (WARN_ON_ONCE(file == NULL)) {
1415 pr_warn("error on getting probe file.\n");
1418 enable_trace_kprobe(tk, file);
1425 ret = target(1, 2, 3, 4, 5, 6);
1427 /* Disable trace points before removing it */
1428 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1429 if (WARN_ON_ONCE(tk == NULL)) {
1430 pr_warn("error on getting test probe.\n");
1433 file = find_trace_probe_file(tk, top_trace_array());
1434 if (WARN_ON_ONCE(file == NULL)) {
1435 pr_warn("error on getting probe file.\n");
1438 disable_trace_kprobe(tk, file);
1441 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1442 if (WARN_ON_ONCE(tk == NULL)) {
1443 pr_warn("error on getting 2nd test probe.\n");
1446 file = find_trace_probe_file(tk, top_trace_array());
1447 if (WARN_ON_ONCE(file == NULL)) {
1448 pr_warn("error on getting probe file.\n");
1451 disable_trace_kprobe(tk, file);
1454 ret = traceprobe_command("-:testprobe", create_trace_kprobe);
1455 if (WARN_ON_ONCE(ret)) {
1456 pr_warn("error on deleting a probe.\n");
1460 ret = traceprobe_command("-:testprobe2", create_trace_kprobe);
1461 if (WARN_ON_ONCE(ret)) {
1462 pr_warn("error on deleting a probe.\n");
1467 release_all_trace_kprobes();
1469 pr_cont("NG: Some tests are failed. Please check them.\n");
1475 late_initcall(kprobe_trace_self_tests_init);